Document k3kx6K8p6aKG9g7w5x3XNdLD

United States Patent no] Wainer mi 3,889,039 [45] June 10, 1975 [541 NUCLEATION AND ORIENTATION OF LINEAR POLYMERS [75] Inventor: Eugene Wainer, Shaker Heights, Ohio [73] Assignee: Horizons Incorporated, Cleveland, Ohio [22] Filed: Apr. 26, 1973 [21] Appl. No.: 354,594 [52] U.S. Cl............ 428/404; 252/62.54; 260/40 R; 260/DIG. 35; 264/108; 428/331; 428/443; 428/446; 428/458; 428/469; 428/900; 428/910 [51] Int. Cl......... B32b 5/16; HOlf 1/11; HOlf 1/30 [581 Field of Search.......... 161/168, 231,402, 411, 161/162, 205, 225, 214, 206; 252/62.54. 252/62.55; 260/40 R, DIG. 35 [56] References Cited UNITED STATES PATENTS 2,400,099 2,999,275 3.024,392 3.051,988 3.070,841 3,359,152 3,515,625 3.673.139 5/1946 9/1961 3/1962 9/1962 1/1963 12/1967 6/1970 6/1972 Brubaker........................... 252/62.54 Blume................................. 252/62.54 Baermann............................. 264/108 Baermann................................ 264/22 Schornstheimer................ 252/62.54 Blume.................................... 161/168 Sedlak................................... 161/160 Hrach................................. 260/40 R FOREIGN PATENTS OR APPLICATIONS 1,284,531 781,128 1,104,089 1,102,844 12/1968 8/1957 2/1968 2/1968 Germany........................... 252/62.54 United Kingdom............... 252/62.54 United Kingdom United Kingdom Primary Examiner--George F. Lesmes Assistant Examiner--Ellis P. Robinson Attorney, Agent, or Firm--Lawrence I. Field [57] ABSTRACT Additions of small amounts of fine particle size spe cialized monoclinic inorganic crystals to otherwise rel atively pure polyalkylene terephthalate molding com pounds increases the rate and extent of crystallization and the specific gravity of the polyalkylene terephthal ate molded part. Both low and high molecular weight polyalkylene terephthalates are improved with regard to physical properties and dimensional stability through addition of these small quantities of these spe cialized monoclinic materials. Under controlled condi tions of injection and forming, anisotropic properties may be obtained as a consequence of the effect and extent of the crystallization of the polyalkylene ter ephthalates which has been promoted by these strongly active nucleating agents. In addition to the improvement of the physical properties of the molded article, the use of these specialized nucleating agents in suitable particle size yields a significant shortening of the retention time of the injection molded material in the mold, this being an item of economic significance. An important aspect of the invention is the added capability of polyalkylene terephthalate crystal orientation by controlled application of magnetic forces to these nucleated compositions, and particularly (a) when such nucleating agents are ferromagnetic in themselves and (b) whether ferromagnetic or not, the preferred nucleating agents are more forcibly aligned into a desired direction (thus promoting crystallization of the polyalkylene terephthalate also in the desired direction) by the action of magnetic fields of force applied to the composition in the molding cycle in the presence of sweeping agents of fibrous and/or acicular nature taken from the class of non-metallic and/or metallic ferromagnetic materials. Not only are the specialized monoclinic nucleating agents useful for promoting crystallization of polyalkylene terephthalates when such nucleating agents are useful in small percentage, but in much larger percentages they can be used as mineral fillers to yield high strength, dimensionally stable, clean surface parts obtained with a molding cycle time of short duration. 17 Claims, 9 Drawing Figures CEL-1338 PATENTED JUNTO 1975 SHEET 1 FIG. I. 3.889.039 FIG. 2. PATENTED JUNTO 1975 SHEET OL. FIG. 4. 3,889,039 PATENTED JUN10 1975 SHEET 0o 3,889,039 FIG. 6. r-T-_6Q-^--.____________________ -- IN S 50 I- - I_____ 1 7n 60 FIG. 7. tl0 50 NS J FIG. 8. FIG. 9. 3,889,039 12 NUCLEATION AND ORIENTATION OF LINEAR force of such strength so that the combination of rea POLYMERS gents not only cause the crystal growth of the polymer BACKGROUND to take place in a desired direction but at the same time orient the fibrous fillers in an identical direction. This invention relates to the improvement of syn 5 It is a fifth object of this invention to permit the poly thetic resins and particularly to the improvement in alkylene terephthalates, and particularly the polyethyl physical properties of both homopolymers such as ene terephthalates, to be molded, nucleated and ori polyalkylene (e.g. polyethylene) terephthalates, poly ented in temperature ranges extending from as low as olefins, polyamides, polymethylmethacrylates, polysul- 100 up to 250 F. (38 to 121 C.) while still retaining fones, polyvinyl resins such as PVC and polystyrenes 10 the fully obtainable strength of the molded part, irre and copolymers such as the ABS family of plastic mate spective of molding temperature, through a combina rials of which acrylonitrile-butadiene-styrene is a typi tion of addition of outside orienting forces in the mold cal member and the thermoplastic elastomers, such as ing cycle with or without subsequent annealing at tem the styrene-butadiene or styrene-isoprene copolymers, peratures well below the glass transition temperature. this improvement resulting from the incorporation of a 15 It is a sixth object of this invention to produce contin specialized class of inorganic crystalline materials as uously extruded sheets, films or foils in any desired ori nucleating agents, into the polymer and the shaping of entation without the need for monaxial or biaxial the polymer by extrusion or injection molding or other stretching and still achieve the type of crystal growth suitable techniques. and orientation which yields strength in ranges equiva The properties and molding may be further improved 20 lent to that available from stretching through the me by the addition of specialized materials which influence dium of a combination of nUcleation, with or without the crystallization of the polymer in a desired manner. sweeping agents in which such orientation is accom The use of nucleating agents to modify the crystalline plished by the application of an outside force. structure of crystallizable polymers is known and is de It is a seventh object of this invention, in the absence scribed in U.S. Pat. No. 3,367,926 (Vocks), U.S. Pat. 25 of the nucleating agents described for the polyalkylene No. 3,585,264 (Thomas) and in British Specifications terephthalate, to orient deliberately added fibrous rein Nos. 1,104,089 and 1,102,844 (both AKU) and else forcing agents in relatively short length in any desired where in the published literature. It has been found that direction by use of a combination of the aforemen the use of such agents is often unsatisfactory, especially tioned "sweeping agents" plus high strength, short fi when they are incorporated in polyalkylene terephthal 30 bers commonly utilized for the reinforcement of engi ates such as polyethylene terephthalates. neering plastics. The engineering plastics include the It has been further found that only when the nucleat polyalkylene terephthalates defined above and at least ing agent is an inorganic crystalline nucleating agent the following: (1) the ABS family of plastic materials with specific properties, is the desired improvement in of which acrylonitrile-butadiene-styrene is a typical sured. 35 member; (2) polyethylenes; (3) polypropylenes; (4) OBJECTS OF THE INVENTION polycarbonates; (5) polyamides; (6) thermoplastic elastomers, such as the styrene-butadiene or styrene- It is a first object of this invention to provide crystal isoprene copolymers; (7) polyvinyl halides; and (8) line nucleating agents of specialized form and unit di polysulfones. mensions for rapid initiation, catalysis and rapid growth 40 It is an eighth object of this invention to provide of the crystallization of the polyalkylene terephthalates molds for injection molding procedures which make taken from the class of polymethylene, polyethylene, possible the application of outside forces in which the polybutylene and polypropylene polyalkylene tereph body of the mold is made of a non-magnetic metal and thalates with special attention to*the polyethylene ter space is provided in such molds for the insertion of ephthalates. 45 magnetic materials to permit the application of mag It is a second object of the invention to provide, netic forces to the mold and its contents in a predeter among these nucleating agents, a type of agent which mined and desired direction. can be oriented in the desired direction by outside It is a ninth object of this invention to provide devices forces so that nucleated and catalyzed crystal growth of in followon equipment utilized for the extrusion of film the base polymer can be caused to take place in a con 50 and sheet which position magnetic forces in a desired trolled direction for ensuring the maximum desired direction in order to achieve orientation of crystalliza strength. It is a third object of this invention to provide addi tion in such film not only in the case where nucleating agents are present but also where such nucleating tional orienting agents which may more properly be agents are absent but magnetizable sweeping agents called "sweeping agents" to the nucleating agents 55 and reinforcement materials are present which materi which will facilitate the orientation of the nucleating als may be lined up in a desired direction for the agents and the attendant crystalline growth of the poly achievement of maximum strength. alkylene terephthalate in a shorter space of time and It is a further object of this invention to provide con with more certainty than if dependence is made totally on the effect of these outside forces on the nucleating 60 trollable means for a desired directional reinforcement of thermoplastic materials by application of mangetic agents themselves. forces to obtain the best advantage of such directional It is a fourth object of this invention to use a combi reinforcment, whether such reinforcement is nucleated nation of the nucleating agents for accelerating the or non-nucleated for crystal growth of the thermoplas crystal growth of the polyalkylene terephthalates, the 65 tic itself through use of magnetizable fibrous reinforce "sweeping agents," fibrous fillers which are known to ment materials added to the composition. add to the strength of formed thermoplastics, such fi Finally, in the case of the polyalkylene terephthal brous fillers being in chopped form, adding an outside ates, it is an object of this invention to provide these 3,889,039 .^eeialized nucleating agents to the composition in suf quired. As may be seen from the figures substantially ficiently high concentration so that with or without ap any direction of lines of magnetic lines of force can be plication of outside forces, they may act as nucleating obtained by suitable positioning of such permanent mineral fillers to yield high strength and mechanical magnetic inserts. It will be readily apparent that the properties, ease of molding, superior surface finish in number, strength and arrangement of such inserts may simplified molds without the need for addition of the be varied according to the magnetic field which is de fibrous reinforcement materials normally used for sired. these purposes. FIG. 5 is a depiction of a magnetized mold defining These and other objects will become apprent from the cross section of a tubulature such as an automobile the description which follows taken in conjunction with the drawings forming a part of this specification, in which: FIG. 1 is a longitudial view, partly in section, of one 10 tire. It is seen that the lines of force shown in FIG. 5 are at right angles to the direction which the tire moves when in use, this being the desired condition which can form of apparatus for accomlishing the present inven be utilized for orientation in the manner described in tion; 15 this invention for obtaining maximum reinforcement in FIG. 2 is a view similar to FIG. 1 or a modification a manner effectively identical with the direction of re thereof; inforcement used for the now well known radial ply FIGS. 3 and 4 are longitudinal views in section show tire. The numbers used for defining various parts of ing an alternative means for obtaining desired magnetic FIG. 5 are identical with those used in the previous fig fields in the apparatus; 20 ures. The embodiment shown in FIG. 5 can be modified FIG. 5 is a view of an apparatus for forming a tubular by the placement of permanent magnets in the same product such as an automobile tire; and manner as in FIGS. 3 and 4. FIGS. 6, 7, 8 and 9 are schematic views intended to FIGS. 6, 7, 8 and 9 show a grossly distorted picture illustrate the orientation of the several contituents in of the structure of the engineering thermoplastic which the Finished product. 25 contains therein, in various configurations, the nucleat FIG. 1 is a view similar to the views in U.S. Pat. No. ing agents 60, the oriented polymer crystals 70 grown 2,849,312 issued Aug. 26, 1958. As shown in the Fig in a preferred direction as a result of the orientation of ure, the apparatus comprises a mold 10 the walls of the nucleating agents, the sweeping agents 80 of non- which define a hollow cylinder, or any other appropri ate shape. The mold is provided with an inlet nozzle 12 30 metallic material which aid in the orientation of the de sired nucleating agents, the combination of magnetic and an outlet orifice 13 through which excess mold contents are discharged in the event of overfilling. Means to fill the mold are shown as an extrusion die 14, provided with a screw 15 for forcing a mixture of poly metallic reinforcing orientation 90, sweeping agents 80, and nucleating agents 60 which make the desired orientation of the nucleating agents and its attendent mer and selected additives through a port 16 which 35 orientation and growth of the polymer crystal itself a matches the inlet opening 12 of the mold 10. Means 18 more positive action whether the nucleating agent ex are provided for bringing the extrusion device into co hibits ferromagnetic properties or not. FIG. 9 not only operation with the filling opening 12. Mold 10 is made defines a situation where both the nucleating agents of either non-magnetic material or of an alloy covered and the polymer crystal which grow therefrom can be with an electrically insulating layer. 40 oriented in a desired direction but also defines the sig Means for creating a magnetic field of suitable nificant advantage of added reinforcement exclusive of strength and intensity for the mold and its contents, the orientation of the polymer crystal by virtue of using such means comprising a source of potential 20 con a combination of magnetic fibers 100 and non nected to an induction coil 22, disposed about mold 10. magnetic fibers 100' in which such magnetic fibers are The coil 22 is constructed in a manner which permits 45 oriented in the proper direction as a function of the im the mold to open along a longitudinal axis for rapid re posed magnetic field acting on fibrous magnetic mate moval of the molded part. This electrical coil contains rials which thus push or sweep the non-ferromagnetic in each turn an automatic connect-disconnect mecha fibers into a desired oriented position. This combina nism so the coil may be opened at right angles to the direction of winding on demand, such connect- 50 tion effect takes place whether nucleating agents are present or not, and also takes place whether such nu disconnect mechanism being readily available as state cleating agents are magnetizable or not. of the art components, thus permitting easy separation The magnetic lines of force in FIGS. 6 through 9 are of the mold from the coil. The magnetic lines of force are shown schematically as the broken lines 30. 55 applied in the directions indicated in these figures and define how nucleating agents may be oriented in a de FIG. 2 is a modification of FIG. 1 showing one man sired direction whether such nucleating agents are fer ner in which these magnetic lines of force may be con romagnetic or not. trolled. The magnetic fields shown ameliorate stresses From examination of FIGS. 2, 4 and 5, it is evident inherent for example, in the region of 40 where the two arms of the T intersect. 60 that the desired changes and directions of these lines of force, the growth of the polymer crystal and the direc FIGS. 3 and 4 illustrate the placing of permanent tion of alignment of various fiber reinforcing agents can magnets 50 as inserts at appropriate places in the mold be made to occur in any desired direction through the wall. The use of the permanent magnets exhibits an ad controlled application of the magnetic field. vantage over the use of an energized electrical coil in that a non-magnetic metal can be utilized for the mold 65 THE DESCRIPTION OF THE INVENTION components and no need for an insulating material Each of the components of the invention will be de such as a ceramic coating or ceramic body is then re scribed separately. 3,889,039 56 A. NUCLEATING AGENTS AND CRYSTAL GROWTH PROMOTERS FOR POLYALKYLENE opment of crystallinity in the polymer. As a generalized example and with identical methods of processing, the TEREPHTHALATES usual polyethylene terephthalate may show a degree of crystallinity substantially less than 20 percent. Such 5 material exhibits a low tensile strength and an extreme The crystal structure of a polymer (generally a func elongation. When the crystallinity is increased into the tion of its chemical makeup) usually defines whether range of 20 to 50 percent, the tensile strength is drasti the physical properties of the polymer can be enhanced cally increased, the degree of elongation is reduced and by increasing the amount of crystallinity in such poly the physical properties generally are improved. In addi mers by mechanical orientation and/or by accelerating 10 tion, the specific gravity of the polyethylene terephthal the growth of crystals during the processing. Usually ate is generally increased from a range normally of the the crystalline structure of the material can be defined order of 1.31 to 1.34 into a range of 1.39 to 1.44. When approximately by measurement of its various cell di an otherwise identical sample of polyethylene tere mensions, such as the length of the crystal axes and the phthalate, irrespective of the source of the material, ex angles which certain of these crystal planes defined by 15 hibiting this low specific gravity, low tensile strength the crystal axes make with each other. Crystalline poly and extreme elongation is processed in exactly the mers which exhibit at least one axis much longer than same manner except that it contains a small percentage the other axes of the crystal are most susceptible to the of a suitable nucleating agent, crystallinity is extended improvement of their physical properties by an orienta into the 30 percent and higher range, the specific grav tion process. Crystalline polymers falling in this class 20 ity is raised into the 1.39 to 1.45 range, the tensile are generally triclinic or exhibit a closely associated strength is drastically increased and the elongation is morphology designated as monoclinic. These systems reduced. Other physical properties, such as flexural usually exhibit one cell dimension which is grossly dif strength and notch resistance are also improved. ferent than the other two. In addition, the angles deter I have found that nucleating agents taken from the mined by the different lengths of the various crystal 25 monoclinic class of crystals exhibiting a c-axis within 10 axes between each of the planes of the crystal are also percent of the length of the c-axis of the polyalkylene usually substantially different from each other in the terephthalate, a beta angle within at least 20 percent of monoclinic-triclinic system. the beta angle exhibited by the polyalkylene tere The polyalkylene terephthalates and particularly phthalate, and preferably one of the other axes within polyethylene terephthalate fall in this category. As will 30 20 percent of the length of either the a or 6-axis invari be seen from Table 1, the length of the c axis in poly ably act as powerful initiators of crystallization (i.e. nu- ethylene terephthalate is approximately twice that of cleation) and additionally powerful promoters of ex the a and b axis, whereas the beta angle in this essen tended crystallization of this class of polymers. This tially triclinic crystal is larger than either the alpha or equivalence of cell dimension and cell angles appears gamma angles of the crystal. The monoclinic and tri 35 to be a requirement for the material to act as a nuclea- clinic crystallographic systems are closely related to tor and promoter of crystalline growth in the polyalkyl each other and are sometimes indistinguishable from ene terephthalate family of plastics and particularly the each other. The monoclinic system includes all forms degree of concordance in dimension and angle also ap containing three unequal axes, having one of their axial pears to be necessary as listed previously. As will be de inclinations oblique. Triclinic systems include all forms 40 fined in later portions of this specification, this im containing three unequal axes in which all intersections provement in crystallinity is exhibited whether or not are oblique. The vertical axes in both systems is gener the material is mechanically deformed in a specific di ally designated as the c-axis. In both crystal systems, the rection which is the usual procedure for orientation angle between the axes a and c is represented by the and improvement of crystallinity normally used in the word beta. In both systems the relative length of the 45 absence of such nucleating agents. axes a and b may be either the same or different but in Nucleating agents which meet the morphological and variably in both systems the length of axis c is greater crystal dimension characteristics provided in the fore than that of either a or b. While this type of non- going description are listed in Table 1 and all of these uniform crystalline structure is common to all of the have been found to be effective for nucleation of crys polyalkylene terephthalates taken from the class of 50 tallization and the propagation of crystalline growth. polymethylene, polyethylene, polypropylene and poly This propagation of crystalline growth takes place butylene terephthalates, the extension of the c-axis is along the c-axis of the polyalkylene terephthalate. most pronounced in polyethylene terephthalate. Thus, Examination of crystals in the preferred particle size while orientation processes polyethylene terephthalate are most effective for the member of this class of 55 ranges which differ radically from the aforelisted re quirements do not show any significant effect on either polymers, similar effects are obtained with all of the initiation of crystallization or propagation of the other members, but to a lesser degree. growth of crystallization beyond that which would nor I have found that certain crystals in the monoclinic mally be obtained through mechanical orientation. In system showing certain similarities to the dimensions and angles of the polyalkylene terephthalates, and par 60 some class, cases, these crystals outside of the described actually interfere not only with orientation but ticularly polyethylene terephthalate, act not only as with the propagation of crystalline growth. very powerful nucleators of crystalline growth in these All of the nucleating agents listed in Table 1 occur polymers under preferred processing conditions, but in naturally or may be made synthetically by either ther addition to very rapid initiation of crystal growth, they also accelerate equally rapidly the extent of the devel 65 mal or hydrothermal techniques, or thereof, by presently known techniques. combinations 3,889,039 7 TABLE 1 8 CRYSTAL DIMENSION CHARACTERISTIC - NUCLEATING AGENTS FOR INITIATION AND CATALYSIS OF CRYSTALLIZATION OF POLYALKYLENE TEREPHTHALATES CELL AXES BETA - ANGLE No. NAME COMPOSITION ab c 1. Polyethyleneterephthalate 2. Lamite 3. Epidote 4. Piedmontite 5. Phlogopite 6. Fluoro- phlogopite 7. Annite 8. Ferri- annite 9. Ftuoro- annite 10. Fluoro- ferriannite 11. Clinohumite 12. Clinozoisite 13. Mangano- Piedmontite _ Beta - calcium ortho silicate /3 - CajSiO, Ca3Al1.sFeu,(SiO<)3OH CajAl, 5Fe,ji(Si04)a0H KMgaCAISiiO.oKOH), KMg3(AISi3O,0)F2 KFe3(AlSi3O10XOH)2 KFe3(FeSi3O,0)(OH)2 KFejfAISijO.olF, KFe3(FeSi3O10)F2 4 Mg^iO, Mg F2 CajAIXSiO,) OH CajAl, jMn, 3(Si04 )3OH 4.56 5.48 8.89 8.95 5.3 5.3 5.4 5.4 5.4 5.4 13.68 8.89 8.95 5.94 6.76 5.63 5.70 9.2 9.2 9.4 9.4 9.4 9.4 4.75 5.58 5.70 10.75 9.28 10.19 9.41 10.3 10.14 10.30 10.34 10.21 10.30 10.27 10.14 9.4 118 (alpha =98.5) (gamma = 112.0) 94.6 115.4 115.4 100.2 100.0 100.0 101.0 99.7 100.2 100.8 115.9 115.7 In all cases, the most effective particle size range for " in both the ferrous and ferric condition. Those that these kinds of crystals is between 0.1 and 3.0 microns. contain iron only in the ferric condition are weakly fer Known procedures are available for griding these mate romagnetic, whereas those that contain iron in both the rials into this particle size range with good efficiency. ferrous and ferric condition are more strongly ferro The amount of nucleating reagent utilized will gener magnetic. For these types of acicular nucleating agents ally fall into a range of 0.01 percent up to about 5 per 0 which contain both divalent elements, particularly cent, unless the nucleating agent is used as a reinforc magnesium, and trivalent elements, such as aluminum, ing mineral filler in which case weight percent addi some or all of the magnesium can be replaced with fer tions up to 50 percent may be used. It is found that the rous iron in the structure without disturbing the crystal- finer the particle size range of the nucleating agent, the 35 line morphology and a significant proportion of the tri- more effective the nucleating agent and the lower the 0 valent element, usually aluminum, can be replaced with percentages which need to be used. For example, if all of the nucleating agent 0.1 to 0.5 micron size range, an amount of nucleating agent in the range of 0.01 to 0.1 ferric iron, again without disturbing the crystalline morphology. Through such replacements, the ferro magnetic properties of these acicular materials, gener- percent is sufficient to yield the maximum of crystalli ally along the c-axis, are strongly increased. Again, a zation available from its presence. If the nucleating ma small but significant portion of the divalent calcium can terial falls in a particle size range of between 0.5 and be replaced with divalent iron and if the mineral also 1 micron, generally at least 0.5 percent of the nucleat ing agent is required to produce the maximum of crys tallization, whereas if the nucleating material has the majority of its particle sizes in a range of 1 to 3 microns up to 3 percent and in a few cases up to 5 percent of the nucleating agent is required in order to yield the maximum benefit from its presence. As indicated, these contains the trivalent aluminum ion, a portion of this can also be replaced with the trivalent iron ion again increasing the ferromagnetic properties. A further im provement in ferromagnetic properties, when both di and trivalent ions are present, is the possibility of re placing part of the divalent ion with the cobalt ion, a possibility which has been established mineralogically ranges indicate the minimum weight percentages re 50 and through the manufacture of synthetic crystals while quired for adequate nucleation. Much higher percent at the same time replacing part of a trivalent aluminum ages are required for mineral filling. with trivalent iron. To some extent, manganese also In summary, and in order to define the effect of the presence of this relatively small quantity of nucleating falls in this beneficial category and as a single element it may be included in the nucleating agents as a partial agent on the crystalline content of the polyalkylene ter- 55 replacement for both di and trivalent ions in the agent, ephthalates and particularly polyethylene terephthalate thereby incorporating a good measure of ferromagne which has been produced without any major degree of tism. Of the nucleating agents which are listed in Table orientation due to mechanical stretching, such non- 1, all of these with the exception of two, namely, item nucleated polymers will generally exhibit or contain 2 (Lamite) and item 12 (Clinozoisite) exhibit this facil- less than 10 percent crystalline material and will usu 60 ity for replacement with the ferro-ferric iron for im ally exhibit a specific gravity in range of 1.30 to 1.34. provement of its ferromagnetism, a property which will With otherwise identical processing, the addition of the preferred nucleating agents described in Table 1 in the particle sizes and ranges given above as preferred will be shown in later discussion to be exceptionally impor tant for the purposes of this invention. increase the crystallinity into the 30 percent range and higher, and will range of 1.39 to increase 1.48. the specific gravity into a 65 B. POLYMERIC MATERIALS SUITABLE FOR THE PURPOSE OF THIS INVENTION It is noted that many of the nucleating agents given For convenience, the raw materials suitable for the in Table 1 contain iron and some of these contain iron overall purposes of this invention may be divided into 3,889,039 9 10 two classes. The first class is the polyalkylene tereph- poses of this invention, coloring agents, and the like, thalates available from a variety of sources and in a va are always mixed into the polymer in molten form. The riety of types to be described hereinafter, and the sec polymer is provided in the form of chips of small diam ond class is the general group of engineering plastics eter or as powder and mixed with the various agents in which include but is not necessarily limited to the ABS 5 dicated in previous sentences in dry form and then series of plastics (acrylonitrile-butadiene-styrene), passed into a melting and mixing chamber which con polyethylene, polypropylene, polycarbonate, polyam sists primarily of a reciprocating screw mechanism ides, thermoplastic elastomers of which the styrene- which may be single or double. Advantageously, the ex butadiene copolymers are an example, the polyvinyl truded mixture is chilled quickly after being expelled chlorides, and the polysulfones. 10 from the body of the chamber, chopped into pellets The polyalkylene terephthalates are usually made by a condensation reaction between the appropriate gly which are of the order of V* inch to V4 inch in length and passed back through the molten stage in the single or col and either terephthalic acid or dimethylterephtha- double reciprocating screw device to ensure perfect late. The reaction is normally continued until a molecu mixing of all the ingredients. The manner in which this lar weight in the region of at least 15,000 is reached. 15 material is manipulated in subsequent processing will Polymerization aids, such as compounds of antimony, depend on the application and shape of the article de usually the acetate, with or without the addition of sired by the consumer. compounds of zinc, again usually the acetate, in small As indicated, in this first mixing step the materials percentages are generally included, along with agents which are normally added to the plastic material in ac for preventing degradation of the fully formed polymer 20 cordance with the state of the art techniques for pro as a consequence of its exposure to high temperatures. tection against thermal and ultraviolet degradation of These agents are usually materials such as the aryl and the polymer are added in this stage along with the vari alkyl phosphites, such as triethylphosphite and/or tri- ous other ingredients which might be utilized for nucle- cresylphosphite. The desired end form is then' pro ation of crystal growth, extension of such crystal duced directly from the reactor to yield sheet, film, foil, 25 growth, and other purposes. fiber, or pellet material which last form may be used for injection molding purposes. When manufactured di D. METHOD OF ORIENTATION rectly into a sheet or fiber, the sheet may be biaxially Orientation of the crystal structure and of the delib oriented to improve specific gravity, crystallization and erately added crystal materials to the molded parts is tensile properties, whereas in the case of the fiber, it 30 accomplished by the controlled application of mag may be stretched in the direction of extrusion so as to yield the maximum tensile strength along the length of netic fields during the process of molding. Not only can the nucleating agents of ferromagnetic type described the fiber as a consequence of crystal orientation. In in Table I be oriented in a desired crystallographic di other cases, the material is extruded without mechani rection by this technique but the polymer crystals cal stretching (this is usually the case for the methylene 35 which are formed and grow as a consequence of the and butylene varieties) into a film form for use as a presence of such nucleating agents are then automati packaging material. In all cases, the molecular weights cally oriented in the direction of orientation of the fer are relatively low, the degree of crystallinity seldom ex romagnetic nucleating agent which has been positioned ceeds 20 percent and is generally quite substantially in the forming piece in the desired direction by the ap below this figure and the product obtained is transpar 40 plied magnetic field. ent. A huge amount of scrap material is available either By artifices involving additions of other crystalline materials, nucleating agents which are not in them in-plant or in the hands of the consumer and particu selves ferromagnetic may be placed in the desired larly in the form of fiber, whether used for spinning alignment and location by the addition of specially de yarns or for the manufacture of tire cord, and in the 45 signed "magnetic sweeping agents" which thus permits form of the polyethylene terephthalate film base which the crystalline growth of the polymer in a nucleated is now commonly used as the standard for photo condition to take place again in the desired direction graphic film. All of these scrap forms may be recovered and alignment. Finally, by further modification of these in relatively pure form by removing extraneous materi "sweeping agents" not only can the direction of crystal als, such as the gelatin emulsion and subbing layers 50 growth of linear polymer itself be controlled but also which appear on photographic film, buttons, zippers, the alignment of fibrous reinforcement materials of ei and other foreign objects which appear in the scrap ther a non-magnetic or magnetic nature can also be yarn and woven cloth and the like. controlled in the desired direction by the application of In general, the higher the molecular weight and the magnetic fields. higher the specific gravity of the polyethylene tere 55 The nature of the various "sweeping agents" their phthalate raw material, the greater the tendency to combinations, and of the various types of non-magnetic crystallize and the easier it is to produce articles of reinforcing agents which may be aligned readily by the good mechanical properties and particularly high tem application of suitably disposed magnetic fields will be perature strength. 60 described in later sections of this specification. In this portion, the generalized techniques for applying the de C. METHOD OF INCORPORATING AND MIXING sired magnetic fields will be described. INGREDIENTS In order to accomplish the desired alignment by the Irrespective of the nature of the polymer or its application of magnetic forces, the throat of the part of source, mixing of the polymer with the various ingredi ents, such as stabilizers against thermal and untraviolet 65 the mold leading directly from the ejection nozzle which contains the molten material used for injection degradation, the nucleating agents of Table 1, reinforc molding or other type of forming, such as the manufac ing agents in fibrous form, sweeping agents for the pur ture of fiber or sheet or when a non-uniform dimen- 3,889,039 11 12 sioi ; piece, such as an injection molded part is being and then leads to the entrance of the injection mold it mao~ and a non-uniform directional part is being made self. This entrance to the injection mold itself is again the sites for application of magnetic forces are so de a ring other suitably shaped enclosure, again produced signed so that the desired magnetic forces can be ap of magnet material which has been magnetized in a di- plied in the desired amount and direction. 5 rection opposite to that utilized for the first magnet so For fiber and sheet, usually suitably positioned per that the appropriate north-south pole requirements are manent magnets are sufficient for the application of maintained. Similar principles will apply to the design such forces, whereas for an injection molded part ei and construction of the mold itself particularly if the ther suitably positioned permanent magnets or the ap part being made is relatively small. To accommodate plication of relative powerful electromagnetic fields are 10 these conditions, the non-magnetic portions of the required. throat and of the mold are made of non-magnetic met Dealing with the injection molding processes specifi als, such as those based on aluminum and its alloys, cally, the molding process involving forming the molten copper and its alloys, zinc and its alloys, and other non material by ejection from the chamber which contains magnetic alloys. Slots are placed in the mold to accom- such a molten material through an opening, generally 15 modate preformed permanent magnets in such slots for designated as the throat of the mold, which may take suitable application of the desired magnetic field. The many shapes depending on the speed with which it is strength and direction of the desired magnetic field desired to have the molten material move into the mold may be determined easily by techniques in which cavity and further the complication required by the dic mock-ups of the mold design are made, generally in a tates of this specification involving orientation and 20 soft plastic material, places for insertion of various per alignment of the crystal structure. manent magnets provided and the direction and In earlier portions of this description, it was pointed strength of the desired magnetic field then determined out that incipient crystals may already exist in linear by the patterns made by iron filings placed inside the polymer compositions even when these linear polymers mold. These simulations are generally sufficient for are in a fairly molten or liquid state, and such incipient 25 substantially all practical purposes but in addition, crystals may have lengths in the range of 10 to 150 A. mathematical computation of both the strength and the When this material is cooled even into the supercooled direction of the magnetic forces which are applied as liquid state, crystal growth beings and progresses rap a consequence of the known characteristics of either idly particularly if proper nucleating agents are present. the permanent magnets used or the strength of applied The speed at which such crystals grow is a combination 30 magnetic fields may be utilized. of the presence of these crystal promoting agents, such Permanent magnets which are suitable for the pur as the nucleating agents described and the temperature poses of this specification are generally those which ex conditions which permit the crystals to grow more rap hibit a coercive force in oersteds, normally symbolized idly, and generally the speed of growth bears some rela by the phrase Hc of a value of 1,000 or greater or more tionship to the glass transition temperature and the 35 generally in which the product of the remanence (gen time intervals during which the material passes through erally designated by the phrase Br is at least in the these various states of matter. As explained earlier, range of 1,000,000 or more and preferably at least providing nucleating forces are present, rapid crystalli 2,000,000. The usual method of designation of this zation generally takes place at or near the glass transi product is generally in the form (BH)mox or equiva- tion temperature though in some cases this can be ac lently (Gauss-Oersteds x 10-6). This product is nor complished at temperatures substantially above this mally designated as the maximum energy product and level. Each of the various linear polymer compositions as a figure of merit for the determination of the behav may operate differently in this respect. For polyethyl ior of the permanent magnet. By mutiplying this prod ene, which has an extremely low glass transition tem uct by the factor of 10-6, manageable numbers are then perature, it is almost impossible to achieve the amor available which indicate that a number of at least 1 and phous state in injection molding no matter how rapidly preferably above 2.0 for this maximum energy product such a material is formed and cooled. Such material defines the preferred series of permanent magnet mate passes directly from the completely liquid state to an rials. almost completely crystalline state in extremely short ( Compositions which fall in this category of usable periods of time without showing any particular evi permanent magnet materials are the "Alnicos" which dence of the formation of a supercooled condition are usually alloys of aluminum, nickel and cobalt with where the material exhibits all the characteristics of the minor amounts of other metals such as copper, tita solid but still shows no evidence of crystallinity. nium and niobium, the "Vicalloys" which are alloys of Advantage of this type of situation is taken in the ,;5 cobalt and vanadium; and ceramic magnets designated throat design. Usually, it is desired to have the crystals by the tradename "Ferroxdur" which are barium fer aligned in a direction parallel to the movement of the rites. Cobalt rare earth magnets are particularly power material through the throat for most purposes though ful. there are rare occasions where directions at right an A somewhat permanent magnet which does not meet gles to the direction of movement may be desired. The fiq the restrictions imposed by previous paragraphs, but imposition of this desired direction may be obtained which requires a frequent polarization in view of its rel easily by the proper positioning of magnets. In the case atively low remanence is the alloy designated in the where the desired direction or orientation is parallel to trade as "Silmanol" which is an alloy of aluminum, sil the direction of movement of the fluid out of the ejec ver and manganese. This material is of interest because tion nozzle, the magnets are placed advantageously as g 5 of the extremely high coercive force it exhibits once it a ring comprising the ejection nozzle itself of the device containing the molten plastic. This ring is then attached to the body of the throat which in itself if non-magnetic is properly magnetized in the proper direction. For these and any other magnetic materials or mag netic fields which are described in this portion of the 3,889,039 13 14 specification, the Curie point must be substantially sections to be lined up in a direction parallel to a longi above the highest temperature to which the magnet is tudinal direction of the fiber. Normally, the fiber is also subjected. All of the materials which are described in this section are in this category. The Curie point is the mechanically strained again in a direction parallel to the length of the fiber to further accentuate the growth temperature at which the material starts to lose its mag- 5 and orientation of the crystal portions of the plastic it netism very rapidly and becomes essentially non self. magnetic or incapable of accepting a magnetic field. In the formation of sheet, monaxial or biaxial stretch When the mold is relatively large or relatively long ing is usually imparted to the sheet in order to develop distances of applied magnetic force are desired, then a oriented properties in the direction of stretching so as preferred practice is the use of magnetic circuits in- 10 to improve the mechanical properties of the sheet. By volving modifications of transformer technology in utilization of suitably imposed magnetic forces in the which magnetic materials with high magnetic permea presence of the desired nucleating agents, or a combi bility are utilized to define the fields of force once a proper electrical field is applied to these high magnetic nation of these nucleating agents and the sweeping agents to be described hereinafter, even in the absence permeability materials in a proper circuit. 15 of such nucleating agents but in the presence of the The advantage of the use of transformer circuits in sweeping agents to be described hereinafter, orienta volving high magnetic permeability materials with ap tion can be accomplished readily by the application of plicable electrical circuits applied thereto is that not magnetic forces alone. When orientation plus nucle- only may these circuits be turned on and off at will but ation is utilized, the superior mechanical properties are very high coercive forces (i.e. high magnetic forces due 20 obtained without the need for the very complicated bi to the exceptionally high saturation flux density which axial stretching techniques normally used on such ma can be imposed on these materials) are available. Ma terials as polyethylene terephthalate sheet or generally terials falling in this category are generally alloys of for the polyalkylene terephthalates and in those cases iron and nickel such as silicon, manganese, chromium, where the crystalline structure of the linear polymer is copper, vanadium, and/or molybdenum. Purified iron 25 highly anisotropic. in the form of alpha iron or ferritic iron is especially An important consequence of the method of mag useful. All of these materials have Curie points substan netic orientation is the ability to apply the magnetic tially above the highest temperature to which would be fields in such a manner that the orientation can take applied to them in the forming of molded process in place in a direction at right angles to the flow of the ma volving the thermoplastics described in this specifica- 30 terial going into the mold. This provides the possibility tion. for orientation at right angles to the direction of the The strength of magnetic fields useful for purposes of flow of materials which is particularly important in this invention fall generally in the broad range between many devices such as the injection molding of elasto 1 and 10,000 gauss. mers for the manufacture of tires and other types of The generalized techniques for control and orienta- 35 tubulatures. tion of injection molded parts have bbeen defined with some degree of particularity. The methods used for E. THE FIRST CLASS OF SWEEPING AGENTS producing oriented fiber and sheet in specific direc In the section dealing with nucleating agents, it was tions need to be further defined. pointed out that the weight percent range in which In the case of fiber where the desire is to obtain the ^ these nucleating agents were effective was a function of maximum of mechanical strength properties in a direc the particle size the smaller the particle size, the less tion parallel to the length of the fiber, the usual process the amount which was needed. A preferred range of for orientation and accelerated growth of the crystal particle size is in the region of 1 micron or less in which involves the application of the magnetic field not only the maximum amount of nucleating agent needed to in the condition where the fiber is still in semi-liquid produce the desired result is of the order of 1 weight form but also when it is still in the supercooled form be percent. When these nucleating agents are ferromag fore it has reached the maximum degree of crystallin netic and susceptible to orientation by magnetic fields ity. Thus, in the case of the formation of polyethylene as described in the previous section, a slight tendency terephthalate a distance is provided between the outlet ^ will be exhibited for these materials to gather close to of a spinnerette nozzle and the point at which mechani the source of the magnetic field. This tendency can be cal elongation techniques are applied with a design sim eliminated or reduced by the speed with which the ma ilar to that previously described in which the "throat" terial is injected into the mold and through the throat of the spinnerette nozzle is composed of a permanent leading to the mold. This question of gathering close to magnet or the high permeability magnetic material with ^ the seat of the magnetic influence versus the degree of an applied magnetic field due to the presence of an ferromagnetism of the materials being placed in the electrical force followed by a section of non-magnetic structure becomes increasingly important as the degree material at the end of which is imposed another mag of ferromagnetism of the materials added is increased. netic field either through the presence of a permanent The class of sweeping agents to be described are non- magnet or a high permeability magnet with associated ^ metallic, high magnetic susceptibility materials in acic- electrical field of opposite sign so as to permit not only ular form, all of which exhibit amply high Curie points. the nucleating materials but the crystals themselves as These materials are used to accelerate or force the ori a consequence of the aligned nucleating materials pres entation of the nucleating agents in the desired direc ent or other "sweeping agents" as defined in further tion. These are listed in Table 2. TABLE 2__________________________________________________ CLASS 1 - SWEEPING AGENTS - MAGNETIC SUSCEPTIBILITY AND CRYSTAL STRUCTURE Susceptibility Crystal 10"^ ergs Morphology Acicular Cr203 CrOj 1,960 22,000 Hexagonal Monoclinic Yes Yes 3,889,039 15 TABLE 2 --Continued 16 CLASS I - SWEEPING AGENTS - MAGNETIC SUSCEPTIBILITY AND CRYSTAL STRUCTURE Susceptibility Crystal 1CH ergs Morphology Acicular CoO CojOj Co30, COj( PO<), Rare Earth Oxides] except La, Y and > Ce J Rare Earth Phosphates] except La, Y, and Ce 1 Fe20, Fe,0,(ac) FePO,, MnO Mn,Oj Mn,0( 18,000 4,900 4,560 7,380 28,110 10,000 to 100,000 25,000 to 150,000 3,586 8,600 11,500 4,580 14,100 12,400 Monoclinic Tetragonal Hexagonal Cubic Monoclinic Hexagonal Monoclinic or rhombohedron hexagonal - tetragonal Hexagonal Cubic Rhombohedron Hexagonal Tetragonal Tetragonal Yes Yes Yes Yes* Yes Yes Yes Yes Yes* Yes Yes Yes Yes In view of their high degree of ferromagnetism and high relative to the paramagnetism of the material, then magnetic susceptibility, these kinds of sweeping agents 20 the use of alternating fields of magnetism are generally are much more readily aligned in a magnetic field than preferred by the application of an external source the relatively weakly ferromagnetic nucleating agents through the medium of a high permeability insert. This which are defined in Table I. As a consequence of this leads to a significant decrease in the amount of material speedly alignment, they tend to sweep other solid mate which will tend to gather around the area of highest rials into the same general alignment as they them 25 magnetization. In addition, the speed with which the selves exhibit as a consequence of the influence of the material flows into the mold also is beneficial in aiding magnetic field. In order to obtain the maximum effect a sweeping action to take place so as to push these ma of this kind of sweeping agent I have found that the vol ume of these sweeping agents should be at least twice terials that tend to congregate around the areas of high est magnetization away from these areas and place the volume of the nucleating agent. Since the specific 30 ^em jn their proportions in the piece to be prepared. gravity of these sweeping agents is generally in the This is automatically the case when a continuously range of equal to and up to twice the specific gravity of moving fiber or shape is being prepared since the speed the nucleating agent, a general figure for maximum ef of production of these fibers and sheet is so high that fectiveness is to use approximately four times the the tendency for the magnetic particles to congregate weight of this type of sweeping agent of that of the nu 35 at the areas of greatest magnetization is sharply re cleating agent normally used. duced. This becomes a more serious problem when in Thus, if the nucleating agent having a particle size in jection molded parts are utilized and here a combina the range of 0.1 to 0.5 microns is utilized in well crys tion of alternating fields and rapid filling of the mold is tallized condition, a proper amount of nucleating agent in this particle size range would be in the range of 0.01 40 sufficient to eliminate the problem. In summary of this section, the use of these sweeping to 1 percent, then the amount of acicular high magnetic agents facilitates the alignment of the nucleating agents susceptibility sweeping agent which is added to acceler which in turn facilitates the alignment of the linear ate the positioning of these nucleating agents and the crystals available from the crystallizing polymer and polymeric crystals which grow in the proper direction as a result would be approximately four times the 45 substantial increases in physical properties sired direction are thereby obtained. in the de weight or in the region of at least 0.04 to 4 percent by weight of the polymer. F. THE SECOND CLASS OF SWEEPING AGENTS In examining the materials and properties of the The second class of sweeping agents to be used as an sweeping agents listed in Table 2, a distinction can be aid in alignment of both the first class of sweeping made between the ferromagnetic and paramagnetic 50 agents and the nucleating crystals themselves but also properties of these materials. The ferromagnetic mate eventually for the alignment of non-magnetic reinforc rials generally exhibit a quite high susceptibility and a ing material are taken from the class of brass plated significant portion of the magnetic force remains after high permeability ferromagnetic materials in short wire the magnetic field is removed varying with each mate form. Such wires will have diameters of the order of 10 rial and depending on the relative degree of paramag 55 microns or less and lengths up to 100 to 2,000 microns. netism versus ferromagnetism. Generally speaking, cer State of the art techniques are available for producing tain oxides of metals, such as iron, chromiun, manga wire in these diameters. Materials in this class are nese and cobalt tend to be more ferromagnetic than chosen which have the highest possible permeability paramagnetic, whereas the phosphates of these ele ments, and the oxides and phosphates of the rare earths 60 with the lowest possible remanence. They are difficult to use with permanent magnets which exhibit very high then to show a high degree of paramagnetism. remanence unless the speed of the flow of material is Materials which exhibit a high degree of paramagne extremely high. If the speed is not extremely high, then tism, however, even though they may show very high a large tendency exists for these high permeability fer magnetic susceptibilities and can be aligned readily in romagnetic materials to congregate at the source of a magnetic field, lose practically all of the magnetism 65 highest magnetism and block the flow and the orienta once the magnetic field is removed. This defines the tion of the desired product. Thus, oscillating or alter manner in which these sweeping agents may be used in nating electric fields are utilized in which the field a practical sense. If the degree of ferromagnetism is moves rapidly from the highest intensity to zero inten- 3,889,039 17 18 sity and then back. Good results are obtained when the out as rapidly as possible and, if the throat design is alternation takes place at no more than 2 to 3 times per proper, this mold filling can be completed in less than second. With materials exhibiting low remanence these 1 second for specimens which weigh less than about 5 high permeability wires will lose sufficient of their mag or 6 ozs. As a consequence of contact of the molten netism so that they can be swept out of the area of high 5 material with the good heat conducting metallic sur est magnetic forces by the speed with which the mate face of the interior portion of the mold a solid skin rial is being injected or moving in a particular cavity forms almost immediately as a consequence of such and then reassume their proper alignment once they contact even though such solid skin may still be in the are inside the cavity without the tendency for collecting supercooled state. Then, immediately the mold is filled around the areas of highest magnetism. Situations of 10 the external magnetic field is applied which is capable this type are much easier to control when a continuous of aligning the most strongly magnetic materials pres form is being prepared such as a fiber or sheet and ent very easily which in turn have their desired action more difficult to control when a fixed injection molded on the weakly magnetic material as a consequence of part is being made. Under these conditions, extremely the sweeping action developed thereon and also in turn high speeds of injection are required. 15 line up the nucleating agents, all accomplished in a very One method of accomplishing this procedure is to short space of time in view of the presence of this solid use a throat which is divided into two sections. The first skin while the interior of the part is still semi-liquid. section is relatively narrow and permanent magnets can Thus, nucleation, orientation and alignment takes be used in this narrow section because through this nar place in the body of the piece in the desired direction row section the flow of the material is extremely high. 20 and amount without the danger for aggregation at the The throat then opens up very substantially, weaker pole pieces which might seriously hinder the proper magnetic forces of oscillating or alternating nature are flow of materials into the cavity. Relatively cold molds then applied thereby reducing the tendency toward ag can be used to accomplish the same purpose except gregation at the points of highest magnetization. that even shorter times between filling the mold and ap From the combination of speed of flow, strengths of 25 plication of the magnetic field are required to obtain magnetic field, and oscillation, a uniform distribution the desired degree of alignment. In this case of films of magnetic materials can then be accomplished in the and fibers, the magnetic field can be applied after the molded article. material has been ejected from the proper forming ori In proper use of these sweeping agents relative to ori fice and since air gaps exist and the solid skin forms al entation of crystal growth, it has been found that many 30 most immediately after ejection providing ejection is thermoplastics, particularly those in the linear homo- into an atmosphere or a fluid which has a temperature polymer class or in the linear class generally have a ten substantially below the melting point, the desired align dency to crystallize with extreme rapidity and conse ment can be forced to take place in the presence of quently nucleation for initiation of the crystallization in even the most strongly ferromagnetic fibrous materials accelerating the growth of such crystallization is not 35 without any possibility of these fibrous materials gath usually required. It has been further found that the use ering at a particular portion of the piece particularly in of the sweeping agents for these types of linear homo view of the fact that during forming the fiber or sheet polymers, and particularly the polyolefins and to a material is moving past the magnetic field at a very somewhat lesser extent the polyamides, exhibit a sur rapid rate so that the dwell time is extremely short. prising degree of orientation as manifested by improve 40 This sweeping action develops a greater significance ment in their physical properties in the direction of ori in accordance with the description of the portion of the entation through the use of either the materials listed invention included in the next section. in Table 2 or combinations of these materials and the high magnetic permeability with relatively low rema nence characteristics of the metallic wires described in 45 G. FIBROUS REINFORCING AGENTS Through, in many cases, a variety of ground up min this section. These materials or the combinations de erals can be utilized for reinforcing a thermoplastic, or scribed apparently exhibit a mechanical sweeping ac for that matter, even a thermosetting material, com tion which acts on the direction of crystallization of the monly used reinforcing agents are fibrous in nature, polymer to force the direction of crystallization along comprised of glass, asbestos, wollastonite and/or syn the lines of force as imposed by the magnetic field. 50 thetic ceramic fibers. These synthetic ceramic fibers It has been pointed out that one of the problems asso are sometimes called glass wool since they are made of ciated with using highly ferromagnetic materials such compositions which are normally not utilized in the as iron wires as an aid to the sweeping action is the ten manufacture of ordinary glass. In many cases, they are dency for these highly ferromagnetic materials to con more refractory variations of high temperature glasses gregate in the area of the source of the magnetic field 55 and the usual technique for their manufacture is to turn which either may block continued movement of the them into fibrous form by blowing high pressure steam material to be formed or may yield non-uniform prop or air through the molten stream that is produced while erties. Under these situations, a somewhat different the materia! is being poured out of the crucible in method of molding and application of the magnetic field is utilized which eliminates the problem. In injec 60 which the material is initially melted. The advantage of the use of these ceramic fibers for tion molding, the polyethylene terephthalate material the purposes of this invention is that iron compounds is injected rapidly into a cavity preferably at or consid can be incorporated in these ceramic fibers to a minor erably above the glass transition temperature which is extent without experiencing a marked decrease in their approximately 120 C. (248 F.) and below the fluid melting point of the material which is in the region of 65 tensile strength, the amount of iron compounds being incorporated being sufficient to make them ferromag 250 to 290 C. (480 to 555 F.). No magnetic field is netic so that they themselves can act as sweeping applied during the filling of the mold which is carried agents. 3,889,039 19 20 The base glasses which may be made by this tech ing this standing period, the fiber bundle breaks down nique are derived from fundamental formulations such to smaller and smaller fibrils to a point where a fiber as calcium aluminum silicate, calcium magnesium alu- which was originally tens of microns in diameter is now minum silicate, aluminum phosphate and the like. As composed of many thousands of fibers which are min- a consequence of modifying these glasses, magnetic 5 ute fractions of a micron in diameter with the length re materials of the type given in Table 2 can be incorpo maining the same. The water is removed by successive rated in these ceramic fibers to yield a degree of ferro washings in alcohol which may or may not be followed, magnetism and/or paramagnetism so that they can op depending on the types of surface active agents which erate not only as reinforcing agents but also can be have to be added at a later time, with combinations of aligned in a desired direction for improvement of physi 10 alcohol and toluene and followed finally by pure tolu cal properties in such direction by themselves. Thus, ene. Surface active agents are added in the last stages such magnetically modified synthetically made ceramic which will adsorb on the surface of the asbestos fiber fibers not only act as sweeping agents in themselves for so as to make these materials compatible with the poly aid in lining up non-magnetic nucleating agents, but at meric system and promote the adherence of the asbes- the same time can in themselves act as fibrous rein 15 tos to the polymer components. For example, if the forcements which are lined up in the proper direction. These kinds of ceramic fibers are particularly useful polymer contains substantial amounts of hydroxyl end groups, a small percentage of citric acid or other or since the degree of ferromagnetism and/or paramagne ganic acid is added in the final washing stages to de tism can be modified to a good extent by the amount velop the bond between the asbestos and the polymer of high magnetic susceptibility oxides that can be incor 3 itself. If a polymer contains acid end groups such as porated in them and all of the materials listed in Table carboxyls, then a slightly basic material such as an or 2 in oxide and/or phosphate form fall in this category. ganic amine is added for surfacing of the asbestos. However, a second and much more important effect These surface active agents for promoting adhesion are is obtained if one is required to use non-magnetic rein generally added in an amount of about 1 percent of the forcements entirely. 5 total amount of fluffed asbestos. Fibrous reinforcments which fall in the category of To serve as an indication of the degree of fluffing completely non-magnetic materials may be taken from the glass, asbestos, wollastonite, and synthetic ceramic which takes place one needs only to measure the bulk specific gravity and the relative increase in bulk spe fibers which do not contain elements or portions of the cific gravity as a consequence of the fluffing action compounds as listed in Table 2. Of these a particular 3 after the asbestos has been thoroughly dried. For exam variety of asbestos which may be designated as "fluffed ple, if one starts with 100 cubic centimeters of normally chrysotile asbestos" is preferred. chopped chrysotile asbestos, after suitable fluffing and Amphibole asbestos is somewhat superior to chryso treatment as described in previous paragraphs, the tile asbestos in its utility but in view of its scarcity and same 100 centimeters will then occupy a volume of the high cost, it it much less commonly used than chryso 1 order of 1,000 to 3,000 cubic centimeters. An exami tile. While most varieties of asbestos are available in nation under the microscope, especially at the highest very long lengths, the most commonly used form for re levels of fluffing indicates that the diameter of the indi inforcement of plastic systems is chopped asbestos gen vidual fibers are now in the range of either fractions of erally in lenghts varying from Vsinch up to %inch. In the microns or in diameters which are below the limit of chopping process the widths of the individual fiber bun resolution of an optical microscope. dles which are obtained as a result may vary in widths The reasons for carrying out this fluffing operation is from as low as 10 microns up to 200 microns or more that a product is obtained which exhibits an exception in width. ally low mass relative to its original length which is re Careful examination of these bundles of chopped fi tained in the fluffing operation and as a consequence bers has established that each presumably individual of this extremely low mass it is easily moved by the type fiber or asbestos is actually made up of many thousands or more still smaller diameter fibrils and such examina of mechanical force which can be imparted to the parti cle through the use of the various sweeping agents tions have indicated that theoretically, that at least, the which had been moved in the direction of desired align width of the individual fibril is no more than a few mol- ( ment by magnetic forces. In addition, in view of the ex ecules. ceptionally high surface area which has been exhibited Since the efficiency of reinforcement of a fibrous ma by this fluffed asbetos an exceptional amount of rein teria) in a plastic matrix is a function of the surface area forcement is achieved with relatively low concentra of the fibrous material exposed it would be of great ad tions of fiber. Consequently, when fiber in the unfluffed vantage to have the choppd fibrous asbestos reduced to , condition, as is normally used, normally will require a its smallest reasonable diameter. This can be accom loading of the order of 20 to 50 percent in order to plished, in the case of asbestos, by transforming the achieve the maximum of reinforcement which one can chopped fiber asbestos into a so-called "fluffed" form. expect by the combination of reinforcing fibers and This involves immersing the fiber in at least 10 and thermoplastic base. Equal or even better results are preferably 100 times its volume of distilled or deionized g achieved from the fluffed material with weight loadings water which contains approximately 1 percent of a wet of 10 percent or less. ting agent such as aerosol OT which is a complex so Thus, in summary of this section, fibrous reinforce dium salt of an organic acid. A variety of cationic wet ments of both non-magnetic and magnetic types may ting agents which contain alkalis as the cation are suit be used to increase the directional properties of the able for the purpose. The mixture of asbestos, cationic 6 thermoplastic being produced. Not only can those fi wetting agent and deionized distilled water is stirred thoroughly and then allowed to stand quietly for at lest bers, synthetically made, which show a combination of ferromagnetism and paramagnetism be aligned in a 24 hours and generally for periods up to 96 hours. Dur- proper direction for a maximum reinforcement but also 3,889,039 21 22 a non-magnetic fiber such as the fluffed asbestos de can be modified broadly by the application of mechani scribed in this secion can be swept into a proper align cal stress while these materials are in the supercooled ment by the imposition of magnetic forces on other fi liquid form and appear to be much more susceptible to brous magnetic materials which are present in the com variations in heat treatment, though a combination of position. 5 suitable heat treatment and mechanical stress comple H. THE DEVELOPMENT OF VARIOUS PHYSICAL ment each other. PROPERTIES OF POLYALKYLENE Probably the most important parameter defining the TEREPHTHALATES AS A CONSEQUENCE OF nature of the physical properties which can be obtained VARIATION IN MOLDING AND FORMING is a measure of the degree of crystallinity, which sub- CONDITIONS 10 ject has been discussed in some detail in prior portions It can be determined that linear relationships exist of this specification. between such easily measured parameters as specific On method for increasing the crystallinity of the gravity and relative viscosity and the properties which polyalkylene terephthalates and again particularly the determine the physical characteristics of a molded polyethylene terephthalates is the use of post- polyethylene terephthalate such as crystallinity and condensation in the solid state which usually involves molecular weight, there appearing to be a direct rela heat treatment at temperatures of the order of 230 to tionship also between crystallinity and molecular 25 0 C. in a vacuum of 0.1 to 10 millimeters for periods weight. In addition, all of the physical properties of the up to 60 hours. Depending on the molecular weight and various polyalkylene terephthalates and other polymers crystallinity of the original polyethylene terephthalate can be modified substantially by such devices as the na 20 which is subsequently subjected to post-condensation, ture of the heat treatment after polymerization, the ef this vacuum treatment can change a substantially fectiveness of nucleating agents for promotion of crys amorphous non-crystalline material into a much higher tallization and the increasing of molecular weight, the specific gravity material showing varying degrees of temperature of molding and similar factors. While the crystallinity. TABLE 3 PHYSICAL PROPERTIES OF VARIOUS POLYALKYLENE TEREPHTHALATES UNDER VARIOUS CONDITIONS PBT1 PMT* PET" PET Com. Grade3 PET 6 PET 6 PET PET PET 666 Tensile Strength Elongation Flexural Strength Mold Temperature Starting Specific Gravity Time in Mold (Seconds) Crystallinity Percent Finish Specific Gravity 8,000 300 12,000 125F 8,200 250 12,000 100F 1.31 20 <10% 1.30 1.31 20 <10% 1.30 8,500 200 14,500 195F 1.40 20 28% 1.375 *Com Graded'5-"' 10,000 75 16,500 275F 8,000 300 12,500 150F 1.40 20 37% 1.40 1.355 20 15% 1.355 10,500 50 17,500 150F 1.3551 20 37% 1.40 8,500 300 12,000 150F 9,000 750 13,500 200F 10,000 250 16,500 255F 1.40 20 15% 1.35 1.40 20 23% 1.37 1.40 20 34% 1.38 'Polybuiylenc Terephthalate 'Polymethylene Terephthalate 'Polyethylene Terephthalate `Netherlands Application No. 6.608,999; February 27, 1967 'Netherlands Application No. 6.5)5.106: February 27. 1967 Prepared as described in this specification. TAnnealcd specimen - see specification. 'Netherlands Application No. 6.617,992, February 27. 1967 All the above contain tricresyl phosphite for thermal s'abilization in molten state prior to injection. PET 6 10,500 250 17,000 325F 1.40 20 37% 1.40 degree of variations in comparing the various polyal 50 Examination of the data given in Table 3 exhibits kylene terephthalates differ in rate and extent, in gen some of the effects of varying kinds of heat treatments eral the variations that may be anticipated as a conse on the crystallinity and physical properties. In these quence of applying a particular treatment, specifically cases, not only is the prior heat treatment important those involving heat treatment, nucleation and pre but also the temperature at which the material is ferred and controlled orientation proceed in the same 55 molded. Thus, for example, polyethylene terephthalate general direction and extent with such similarity that which has not been subjected to post-condensation each member of the group of polyalkylene terephthal treatment is essentially amorphous, will exhibit a spe ates can be expected to be varied similarly with similar cific gravity of approximately 1.335 and will generally treatments. show a crystallinity of less than 5 percent. By utilizing Probably the most important single parameter with 60 the vacuum treatment heretofore described, both the regard to the development of desired physical proper specific gravity and the crystallinity can be regularly ties in this group of materials is the percentage of crys increased as a function of the time of treatment in the tallinity. post-condensation step in the solid state under vacuum 1. THE PHYSICAL PROPERTIES OF THE POLYALKYLENE TEREPHTHALATES AS A FUNCTION OF HEAT TREATMENT conditions. Through such post-condensation steps crys65 tallinities up to close to 100 percent can be achieved, providing, however, sufficient stabilizers are present to prevent thermal degradation. By varying the conditions The physical properties of the polyalkylene tereph of post-condensation, followed by injection molding, thalates and particularly th polyethylene terephthaltes, percent or greater. 3,889,039 23 24 parts can be made which exhibit a tensile strength of the order of 8,000 lbs. p.s.i. with an accompanying elongation of around 300 percent, this being equivalent to a specific gravity in the range of 1.35 to 1.36 and obtained by injection molding of materials exhibiting a specific gravity of around 1.36 into a mold that is at 150 F. or cooler. If such materials are then annealed to 150 C. as indicated previously, the specific gravity a crystallinity in the region of 15 percent and up to a 5 increases, the degree of crystallinity increases, the ten tensile strength of 10,500 to 11,000 lbs. p.s.i., elonga sile strength increases and the elongation is decreased tions of 250 percent with crystallinities in the range of somewhat. 34 to 37 percent. Thus, as defined in this section and to some extent Starting with the material exhibiting a specific gravity summarized in Table 3, heat treatment of various types in the range of 1.335 (essentially an amorphous non 10 may have a profound effect on the mechanical and crystalline material) and subjecting this material to a physical properties of a shaped article produced from post-condensation for 30 hours at 230 C. at a vacuum the polyalkylene terephthalates and particularly the of 0.1 millimeters, a specific gravity in the range of 1.40 polyethylene terephthalate. to 1.42 is achieved and the crystallinity obtained as a The figure of merit which represents the clearest def- consequence is claimed to be 28 percent. This material 15 inition of the combined effect of these various heat was originally polymerized using antimony oxide as the catalyst without any specialized materials added delib treatments is the degree of crystallinity which in turn appears to be a function not only of specific gravity but erately to prevent thermal degradation on post also of relative viscosity which again in turn appears to condensation. Contrarywise, a material containing a be a function of molecular weight. mixture of zinc and antimony compounds as a polymer 20 The description in this section and the data given in ization catalyst and utilizing triaryl phosphites as a sta Table 3 are introduced at this juncture to serve as a bilizer against thermal degradation was polymerized in basis for establishing the nature of the improvements the normal manner using the same degree of post which are imparted to molded polyethylenecondensation as defined in reference 4 and 5 of Table terephthalate parts as a function of the novel materials 3. Again, using the identical post-condensation cycle, 25 and procedures defined in the present specification. this type of polyester exhibited a crystallinity of 34 per cent as against the 28 percent shown for the references EXAMPLES of record. Having described my invention and the platform on The degree of crystallinity and the nature of the phys which the invention is based, such platform being de ical properties as a function of heat treatments utilizing 30 tailed in Table 3, following are examples of my method the type of polyethylene terephthalate which was poly of practice. merized originally with a combination of zinc and anti mony salts as catalysts in the presence of aryl phosphite Examples 1 through 10 are summarized in Table 4. In this particular set of examples the polymer of the stabilizers has been described earlier in this specifica starting specific gravity listed was mixed with the nucle tion. If this material is post-condensed in accordance 35 ating agent and tricresyl phosphite under a nitrogen with the heretofore described conditions for about 5 blanket while the polymer was maintained in the mol hours, a gravity of 1.355 is obtained with a crystallinity ten state. The melting temperature used for this pur of 15 percent as shown in the tables, when the material pose was in a range of 500 to 535 F. (260 to 280 C.) is injection molded into a mold having a temperature and the mixer utilized was a high intensity sigma type of 150 F. When this same material is again injected 40 mixer. A period of 3 to 5 minutes mixing in the molten molded into a mold having a temperature of 150 F. state was sufficient to obtain the desired degree of uni (65 C.) and then annealed at approximately 300 F. formity. The mixer is fitted with a heremetically sealed (150 C.) for 5 minutes after it has been ejected from top with seals capable of withstanding pressures up to the mold, the specific gravity is increased from 1.355 1,000 p.s.i. After mixing is completed, the molten mix to 1.40, the tensile strength is increased, and the 45 ture was transferred by ejection and transferred di degree of crystallinity is increased to 37 percent. rectly to the barrel of a reciprocating screw injection If polymerized PET is abruptly cooled after extrusion molding machine. an amorphous and transparent material is obtained, The results obtained as a function of various starting this being the desired requirement for the formation of transparent sheet. Such materials will have tensile 50 conditions such as starting specific gravity and molding temperature are defined in Table 4. Not only is the pro strengths in the range of 7,000 to 8,000 p.s.i. and gen found action of the nucleating agent established but erally will exhibit an elongation in the region of 300 also the effect of starting specific gravity and molding percent. If this material is annealed for a short period temperature on the physical properties of the finished of time at 150 C., as indicated previously the object becomes opaque, the specific gravity is increased, the 55 products, such variations being in accordance with the effect of similar type variables as defined in Table 3. crystallinity is increased, and the tensile strength ob Physical data not defined in Table 4 is of particular tained will be in the region of 10,000 to 11,000 p.s.i., interest. The physical properties of the injected molded with an elongation varying between 50 and 300 percent structure are approximately equivalent irrespective of depending on the temperature at which this material is annealed and also the specific gravity and crystallinity 60 direction indicating that no specific orientation has taken place. The notch resistance of a non-nucleated which is available in the starting materials. These ef specimen and particularly one which shows a crystallin fects are much more pronounced with relatively high ity of 30 percent or less is generally in the range of 1.0 gravity starting materials than with low gravity starting to 1.2 foot pounds. However, it is interesting to note materials although the same general trends are exhib 65 that as the crystallinity increases in these non-oriented ited in either case. Thus, transparent, essentially amor specimens the notch resistance rises steadily to a point phous, relatively low tensile strength (about 8,000 where it reaches a figure of approximately 3 foot p.s.i.) and high elongation (about 300 percent) can be pounds and a crystallinity level of about 65 3,889,039 25 26 Most important, however, is the very substantial im Table 3. More important, however, is te pronounced provement exhibited over the prior art. For example, improvement in crystallinity which is exhibited by the Netherlands Application No. 6,515,106 (reference 5 presence of a properly chosen nucleating agent utiliz from Table 3 of this specification) claims that the crys ing a sutiable thermally stabilized polyalkylene teretallinity of a post-condensed polyethylene terephthal- 5 phthalate. These improved results are particularly no ate under similar post-condensation conditions are table on examination of the crystallinity data reported used in this description was apaproximately 28 percent in Table 4. TABLE 4 EFFECT OF NUCLEATING AGENT (BETA-CALCIUM-ORTHOSILICATE) ON PHYSICAL PROPERTIES OF POLYALKYLENE TEREPHTHALATES'-2 EXAMPLE NO. i 2 345 678 9 10 Type polyalkyleneterephthalate Molding Temperature Starting Specific Gravity Finish Specific Gravity Starting Crystallinity Finish Crystallinity Tensile Strength p.S.l. Elongation (%) PBT PBT 125F 250F 1.31 1.31 1.34 1.37 <10% <10% 22% . 32% 9.300 10.400 170 80 PMT I00F 1.31 1.34 <10% 20% 9,500 150 PMT 250F 1.31 1.37 <10% 30% 11,000 60 PET 100F 1.355 1.385 15% 30% 10,000 200 PET 150F 1.355 1.395 15% 35% 1 1,000 150 PET 255F 1.355 1.410 15% 43% 12,500 100 PET 100F 1.400 1.420 37% 48% 14,000 150 PET 150F 1.400 1.450 37% 65% 16,000 100 PET 255F 1.400 1.480 37% 84% 19,000 60 Mixed into polymer in molten state under nitrogen before injection molding. Also add 1% tricresylphosphite for stabilization purposes prior to melting. Particle sue of nucleating agent is 0.3 microns; amount of nucleating agent for each example is 0.1% by weight of the polymer. and after the addition of crystalline accelerating liquids Examples 11 through 25 are shown in summarized and nucleating agents, the crystallinity obtained was 34 30 form in Table 5. These materials were mixed in the percent, indicating that in accordance with the prior art molten state with the nucleating agents defined in the addition of crystalline promoting liquids and the Table 1 and with the addition of the tricresyl phosphite nucleating agents described in the prior art had a rela for stabilizing purposes in the manner described for the tively slight effect on the crystallinity and the physical examples shown in Table 4 and injection molded also properties of the finished specimens. These references 33 in the manner previously described. In general, the evi from the prior art, however, do not define the use of a dence indicates that all of the nucleating agents of the thermal stabilizer in remelting as utilized in these speci generic description given in previous portions of this fications so that strictly speaking the data are not to specification are effective for purposes of improving tally comparable. Nevertheless, through the addition of crystallinity and physical properties. However, there is these stabilizing agents, coupled with a proper choice a trend, not too well defined, which indicates that the of molding conditions, crystallinities of same order of similarity of the beta angles of the nucleating agent and magnitude as defined in Netherlands Application No. the beta angle of the base polymer is probably a more 6,515,106 can be obtained without the use of crystal important concomitant variable for improvement of line promoting liquids or the nucleating agents defined crystallinity and physical properties than the required in the referred to Netherlands application as shown in 43 similarities between various cell axes. ^BLE 5 EFFECT OF NUCLEATING AGENTS LISTED IN TABLE I ON PHYSICAL PROPERTIES OF PET (SPECIMENS MOLDED AT 325F. AND 20 SECONDS HOLDING TIME) Example Number 1I 12 13 14 15 16 17 18 19 20 21 22 23 24 25 Nucleating Agent Name Table 1 2 2 2 2 4 4 5 6 7 8 9 10 11 12 13 Particle Size-microns 0.1 0.5 1.0 2.0 1.0 0.5 0.3 0.5 1.5 1.5 0.5 0,3 0.2 0.5 0.5 Percent Agent 0.2 0.5 2.0 3.0 0.5 1.0 1.5 1.0 2.0 3.0 1.0 1.0 3.0 1.0 1.0 Starting Specific Gravity 1.400 1.400 1.400 1.400 1.400 1.400 1.400 1.400 1.400 1.400 1.400 1.400 1.400 1.400 1.400 Finish Specific Gravity 1.445 1.442 1.440 1.433 1.420 1.430 1.440 1.425 1.410 1.405 1.471 1.456 1.416 1.475 1.445 Starting Crys. % 37 37 37 37 37 37 37 37 37 37 37 37 37 37 37 Finish Crys. % 63 59 56 53 48 51 56 50 44 39 77 68 46 54 63 Tensile Strength p.s.i. 16,000 15,500 15,000 14,500 14,000 14,200 15,000 14,100 12,500 11,000 18,000 16,500 13,600 14,500 15,800 Elongation Percent no 125 135 140 150 150 100 125 200 250 75 100 160 135 125 I Vacuum treated at 230C.. 10 microns pressure, for 30 hours before admixture in molten state with nucleating agents (polyethylene terephthalate) and 1% tricresyl phosphite as j thermal stabilizing agent. Mixing in molten state carried out for 3 to 5 minutes under a nitrogen blanket. 3,889,039 27 28 Examples 26 through 34 are summarized in Table 6 gation is increased by a factor of 20 to 50 percent, thus and define the effect of a combination of nucleating establishing the strongly directional aspects imposed by agents, plus the non-metallic magnetic sweeping agents the nature of combinations and conditions defined for with and without the presence of the magnetic field. Examples 3 I through 34. TABLE 6 EFFECT OF NUCLEATING AGENTS PLUS NONMETALLIC SWEEPING AGENTS (TABLE 2) ON PHYSICAL PROPERTIES OF PET (POLYETHYLENETEREPHTHALATE) Example Number Nucleating Agent Name Table 1 26* None 2V 10 28s 10 293 None 301 None 31* 10 32! 10 33= 10 34* 10 Particle Size Microns 0.3 0.3 None None 0.3 0.3 0.3 0.3 Percent Agent _ 1.0 1.0 None None 1.0 1.0 1.0 1.0 Sweeping Agent None None None Acicular iron oxide Acicular iron oxide Acicular iron oxide Co3(PO<)2 Gd PO, Particle Size Microns _ -- -- 1.0 1.0 1.0 0.5 1.0 0.5 Percent Agent _ -- -- 5.0 5.0 5.0 4.0 6.0 4.0 Molding Temp. Molding Temp. I5QF.___________________325F. T.S. p.s.i. Elong. % T.S. p.s.i. Elong. % 8,500 300 10,500 11,500 200 16.500 13,500 180 21,000 7,800 210 9,500 8,900 300 10,900 16,000 170 25,000 17,500 150 27,000 15,500 180 23,000 17,000 150 24,000 250 100 80 180 250 70 60 70 70 'Vacuum treated polyethylencterephihalate for 30 hours at 230 C. at 10 microns. Mixed in molten state with above plus 1% tricresyl phosphite. 'Applied magnetic field; 5,000 gauss, alternated. 'No magnetic field applied. Again, the starting raw materials were mixed and in Examples 35 through 44 are given in Table 7 and de jected in the manner as described for the examples cov fine the effect of various fibrous reinforcing agents ered by Table 4. under various conditions, these conditions being the In examining these data, it should be pointed out that absence of nucleating agents without a magnetic field, in the absence of nucleating agents and non-metallic 35 the presence of nucleating agents in the presence of a magnetic sweeping agents relative to the normal poly magnetic field and in combination with the Table 2 ethylene terephthalate as defined in this specification, class of sweeping agents, the presence of nucleating that the application of a magnetic field has relatively no agents combined with Table 2 class of sweeping agents, effect on the physical properties of the finished prod plus brass plated wire in the alpha ferrite condition with uct. The application of a magnetic field on a nucleating 40 or without the presence of fluffed asbestos. agent which exhibits magnetic properties and its bene The data given in these tables indicate that brass ficial effect is defined by comparison of examples 27 plated iron wire even though present in an amount as and 28. Example 29 shows that relatively little, if any, improvement in physical properties is shown by the low as approximately 2 volume percent exhibits distinct reinforcing properties and that asbestos unquestionably presence of the acicular sweeping agent in the absence 45 does. However, the most important pieces of data in of a nucleating agent and while some improvement is this table indicates that even though the class of mag obtained under these conditions as shown in Example 30 on the application of a magnetic field the improve ment is relatively minor, indicating that these acicular netic sweeping agents given in Table 2 are effective for improving the degree of reinforcement in the presence of nucleating agents, that much stronger sweeping sweeping agents are reinforcing agents under the best 50 agents such as the alpha iron and more effective in this of conditions only to a minor extent. However, when regard and notable in their improvement of the one combines nucleating agents with the non-metallic strength made available by asbestos. Again, as before, magnetic sweeping agents as shown in Examples 31 the presence of the magnetic field make these physical through 34, in the presence of a magnetic field, the im properties highly directional. In the absence of the provements obtained are pronounced. 55 magnetic field the properties are roughly the same in all In addition to the foregoing, it has been found that directions but at lower levels than those listed in Table the properties are strongly directional. The properties 7, since these values are the values which are given in listed in Table 6 are parallel not only to the direction a direction parallel to the direction of extrusion and of application of the magnetic field, but also parallel to parallel to the direction of the application of the mag the direction of molding. The notch resistance under 60 netic field. One of the more important determinations these conditions is increased when measured at right listed in this table is the effect which the presence of angles to the direction of the magnetic field in the di the highly magnetic type of sweeping agent has on the rection of molding over that obtained from a non- physical properties in the specimen with regard to rein nucleated, non-swept similar raw material such as de forcement outside of that obtained from nucleation in fined in Example 26. In addition, both tensile strength 65 a specific direction, this being the reinforcement which at right angles to the direction of molding is reduced most evidently takes place by forcing the asbestos fi generally by a factor of 10 to 25 percent whereas elon- bers to line up in a particular desired direction. 29 TABLE 7 3,889,039 30 EFFECT OF REINFORCING AGENTS UNDER VARIOUS CONDITIONS ADDITIVES (1) + (3) Iron Wire Asbestos121 Molding at Molding at Example Weight Weight 150 F. 325 F. Number Base % % T.S. T.S. p.s.i. Elong. p.s.i. Elong. 35 Ex. 29 10 36 Ex. 30 10 37 Ex. 31 10 38 Ex. 29 10 39 Ex. 29 10 40 Ex. 30 10 41 Ex. 30 10 42 Ex. 31 10 43 Ex. 31 10 44 Ex. 29 -- _ 8,700 200 10,000 160 -- 9,800 250 12,000 200 -- 19,500 160 29,000 70 10 9,600 110 12,000 140 30 15,400 40 26,000 20 10 12,800 140 18,000 80 30 19,800 110 29,000 60 10 24,000 70 36,000 30 30 30.000 50 42,000 15 30 14,200 80 24,000 20 "'Alpha ferrite brass plated iron wire - 3/16" to 'A" length, 10 microns diameter. a>Fluffed asbestos - 1/16" to lA" length. '"When magnetic field is applied, the flux density is 10 gauss. The effects of magnetically oriented and swept rein the respective plastic indicated in the talbe, the physi forcement of polymers outside of the field of the poly- cal properties obtained in the absence of a magnetic alkylene terephthalates are shown in Examples 45 field are only slightly better than that when asbestos through 65 and summarized in Table 8. The two types alone is used in the absence of the magnetic wire and of fibrous reinforcements were brass coated ferritic 25 in the absence of the magnetic field. iron and fluffed asbestos. However, magnetic wires, Of particular interest are the examples encompassed stronger than ferritic iron, also brass plated can be used in Nos. 61 through 65. This material is a thermoplastic in the place of the ferritic iron, if desired. Again, the elastomer and after the various types of reinforcements significant reinforcement characteristics of the brass are applied, not only are the tensile properties im plated ferritic iron may be seen from examination in 30 proved, but the materials still exhibit elastomeric prop the table, remembering again that the volume percent erties. In other words, if a stress is applied so as to is less than 2 percent of the base plastic. Thermally sta change the dimensions of the piece, the piece returns bilized base plastics were used throughout. The most to its original dimension once the stress is relieved. notable effect is the combination of the magnetic metal When a very high percentage of the magnetic wire is wires and fluffed asbestos in a magnetic field in which 35 used in combination with the asbestos with the rela the combination of the two yields a result superior than tively weak thermoplastic elastomer given in Table 8, either of the two used alone or better than when the namely, the styrene-butadiene, a very high strength two are used together in combination in the absence of elastomer is obtained with excellent tensile strength a magnetic field. Thus, when the mixture of the mag properties and good elongation as defined in the table netic wire and the asbestos are injection molded with 40 while still retaining elastomeric properties. TABLE 8 Example Number 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 EFFECT OF MAGNETIC ORIENTATION REINFORCEMENT OF VARIOUS POLYMERS Polymer Type Mixing and Injection Mold Temperature Temperature Additives by weight Iron Wire2 Asbestos3 V Tensile Strength Elong. % ABS' " " Nylon 6/6 " " Polycarbonate " Polypropylene " " Styrenebutadiene4 " " " " 450F. " " " 560F. " " 600F. " " " 500F. " " " 375F. '' " " 250F. " " " 250F. " " 250F. " 250F. " 200F. " " " _ 10% 10% -- -- 10% 10% -- -- 10% 10% -- -- 10% 10% -- 10% 10% 60% 20% -- 20% -- 20% -- 20% -- 20% -- 20% -- 20% -- 20% 20% -- 20% 20% p.s.i. 7,000 16,000 8,000 21,000 12,000 24,000 13,000 29,000 9,000 25,000 11,000 33,000 5,000 12,000 6,500 20,000 2,000 7,000 2,800 12,000 36,000 15 4.0 15 10 60 3.0 50 30 120 2.0 80 60 600 80 250 80 1,000 50 800 400 80 `AeryIon it n!e-butadiene-styrene *Same as described in Table 7 (magnetic field, 10 gauss). ^Same as described in Table 7 (magnetic field, 10 gauss). Thermoplastic Elastomer 3,889,039 31 32 polyethylene terephthalate, polypropylene terephthal EXAMPLE 66 ate, polymethyleneterephthalate and polybutylene terephthalate. Same as Example 8, except that 20 percent beta cal 4. The article of claim 1 wherein the amount of nu- cium ortho silicate (Larnite) of 0.5 micron average size 5 cleating agent is between 0.01 percent and about 5 per was added as a mineral filler. In this case, a tensile strength after molding of 26,000 p.s.i. was achieved cent by weight of the polymer. 5. The article of claim 1 wherein the particle size of with an elongation of 30 percent. the nucleating agent is 0.1 to 0.5 microns. EXAMPLE 67 6. The article of claim 1 wherein the nucleating agent 10 is an acicular inorganic silicate material capable of Same as Example 10, except that 20 percent of Lar being aligned by magnetic forces. nite of 0.5 microns average size was added yielding a 7. The article of claim 1 wherein the nucleating agent tensile strength of 34,000 p.s.i. and an elongation of 5 is a silicate containing both ferric iron and ferrous iron. percent. 8. The article of claim 1 wherein the polymer is a EXAMPLE 68 15 polyethylene terephthalate and the solid inorganic ma terial is beta calcium orthosilicate. Same as Example 8, except that 35 percent of 0.5 mi cron average size Larnite was added yielding a tensile strength of 34,000 p.s.i. and an elongation of 8 percent. 9. The article of claim 1 additionally containing up to about 20 percent by weight of at least one magnetic non-metallic sweeping agent selected from the group EXAMPLE 69 20 consisting of oxide and phosphate compounds of Cr, Co, Fe, Mn or rare earth elements other than La, Y and Same as Example 10, except that 35 percent Larnite Ce. of average particle size of 0.5 microns was added yield 10. The article of claim 1 which has been subjected ing a tensile strength of 42,000 p.s.i. and an elongation to a magnetic field of between 1 and 1000 gauss during of 3 percent. 25 at least a part of the molding of the article. I claim: 11. The article of claim 1 additionally containing 1. A shaped synthetic polyalkylene terephthalate short pieces of high permeability ferromagnetic metal polymer article with enhanced physical properties con sisting essentially of the following: lic materials which act as magnetic sweeping agents during the molding of said article, or as reinforcements a body of liner polymer consisting of amorphous and 30 for said article. crystalline segments and up to 50 percent by 12. The article of claim 9 additionally short pieces of weight of a nucleating agent consisting of particles of a solid inorganic acicular silicate material dis high permeability ferromagnetic metallic materials which act as magnetic sweeping agents during the tributed uniformly throughout said body and ori molding of said article, or as reinforcements for said ar- ented in a preferred direction, said inorganic mate 35 tide. rial consisting of crystals with A, B, and C-axes, the 13. The article of claim 12 containing brass plated length of the C-axis of said crystals being within 10 iron or steel wires having diameters less than about 10 percent of the length of the C-axis of the crystalline microns and lengths from about 100-2000 microns said polymer, and the lengths of either the A or B axis wires being oriented in the same sense as said polymer. of said crystals being within 20 percent of the 40 14. The article of claim 13 additionally containing up lengths of the A or B-axis of the crystalline poly to 20 percent by weight of a fibrous reinforcing agent mer, and the angle between the A-axis and the C- selected from the group consisting of glass fibers, as axis of said inorganic crystalline material being bestos fibers, wollastonite fibers and glass wool fibers. within 20 percent of the angle between the A-axis 15. The article of claim 14 wherein the reinforcing and the C-axis of said crystalline polymer. 45 agent is amphibole asbestos. 2. The article of claim 1 wherein the particle size of 16. The article of claim 1 shaped by injection mold said particles of solid inorganic material is between 0.1 ing. and 3 microns. 17. The article of claim 1 which has been subjected 3. The article of claim 1 wherein the polyalkylene to a heat treatment after molding. terephthalate is selected from the group consisting of :rf\ ***** 55 60 65