Document pBmbrMoVK6L7pwBVbERno5JGw

United States Patent [19] Kusumgar et al. [li] Patent Numben. [45] Date of Patent: 4,795,477 Jan. 3,1989 [54] PRESTABLE POLYACETAL COMPOSITIONS [75] Inventors: Rsjal Kusumgar, Livingston; K. M. Natarajan, N. Brunswick; Carl A. Amond, Berkeley Heights, all of N.J. [73] Assignee: Celanese Corporation, Bridgewater, N.J. [21] Appl. No.: 886^75 [22] Filed: Jul. 16,1986 [51] IntCL4.............................................. D06P1/16 [52] U.S. CL......................................... 8/471; 8/467; 427/256 [58] Field of Search......................... 8/467, 471, 506; 525/154; 428/207, 156, 914; 427/256 [56] References Cited U.S. PATENT DOCUMENTS 3,476,832 11/1969 Pritchard ............................. 525/154 3,536,673 4,277,577 4,406,662 4,465,728 4,587,155 10/1970 Parrim...................................... 264/78 7/1981 Burg et al.............................. 525/154 9/1983 Beran et al.................................. 8/471 8/1984 Haigh..................................... 428/156 5/1986 Durand...................................... 8/467 OTHER PUBLICATIONS "Hot Stamping Shows A World of Versatility", by George Smoluk, Modem Plastics, Dec. 1985, pp. 52-55. Primary Examiner--Paul Lieberman Assistant Examiner--John F. McNally Attorney, Agent, or Firm--Depaoli & O'Brien [57] ABSTRACT The printability of oxymethylene polymers such as by the heat transfer of sublimable dyes is improved by the addition of an amorphous or partially crystalline poly mer to the oxymethylene polymer molding composi: tion. 19 Claims, No Drawings 4,795,477 12 ene dimethacrylates and alkylene diacrylates) by pre PRINTABLE POLYACETAL COMPOSITIONS heating the articles. While not directed specifically to heat transfer print BACKGROUND OF THE INVENTION ing, U.S. Pat No. 3,536,673 is directed to improving the The present invention relates to a process of heat 5 dyeing of synthetic textiles, more particularly polyole transfer printing the surface of shaped articles of poly fin textile fibers with disperse or metallized dye stuffs. acetals with sublimable dyes. In this particular patent, polyolefin textile fibers, in Heat transfer printing is a process for transferring particular, polypropylene fibers are modified to en sublimable disperse dyes to a receiving substrate by hance the dye-receptivity thereof by mixing the poly sublimation of the dye from a printed intermediate or 10 olefin with 5-25% by weight of polyoxymethylene. auxiliary carrier and diffusion of the gaseous dye into Commercially, only a few thermoplastic resins have the surface of the receiving substrate. The intermediate been printed by the heat transfer technique. These are carrier may be of any of several appropriate materials polybutylene terephthalate such as marketed under the including paper, metal, such as aluminum or steel, plas tradename Celanex from Celanese Corporatio as well as tic, or fabrics optionally coated with various resins such 15 polycarbonate and polybutylene terephthalate and as vinyl, polyurethane, polytetrafluoroethylene, or the polycarbonate blends. A discussion of hot stamping like. All paper printing techniques, including gravure, plastic materials is given in "Hot Stamping Shows a lithography, rotary screen, and flexography, with their World of Versatility", George Smoluk, Modem Plastics, respective advantages and limitations have been used to December 1985, page 52. print the carrier with the ink containing the sublimable 20 One particular engineering thermoplastic which has disperse dyes. The dye is transferred by pressing the not previously been printed satisfactorily by the heat printed surface of the intermediate carrier into intimate transfer process is polyacetal or oxymethylene polymer contact with the substrate surface to be printed and resin. Oxymethylene polymers, having recurring --CH- applying sufficient heat and pressure to sublime the dye 2O-- units have been known for many years. They may and cause diffusion of the dye into the substrate. Upon 25 be prepared by the polymerization of anhydrous form cooling, the dye condenses and is permanently adhered aldehyde or by the polymerization of trioxane which is to the substrate. It is commercial practice to print textile materials by sublimation printing from carriers printed or coated with disperse dyes in the form or an ink or paste. In the heat transfer printing of textiles, a wide variety of re ceiving substrates have been used including such syn 30 a cyclic trimer of formaldehyde. The oxymethylene polymers are highly crystalline in nature and thus when molded or otherwise shaped into articles do not allow sufficiently deep penetration of the printing inks. Conse quently, oxymethylene polymers have not been accept thetic polymers as polyacrylonitrile, polymers of vinyl compounds such as acrylic esters, acrylic amides, vinyl able materials as substrates for the sublimation printing process. pyridine, vinyl chloride, vinylidene chloride, etc.; co 35 It is widely known to modify the properties of oxy polymers of dicyanoethylene and vinyl acetate; poly methylene polymers by incorporating additives therein. urethane; polyolefins; cellulose acetates; polyamides; Thus, use of various additives have been suggested for and aromatic polyesters such as those from terephthalic improving the mechanical and physical properties such acid and ethylene glycol or l,4-di(hydroxymethyCy as the impact strength of oxymethylene polymers. The clohexane. 40 following patents are illustrative of such art. With the wide spread use of plastic articles in business U.S. Pat No. 3,281,499 discloees improving the ther and in the home, there is an obvious need for suitably mal stability and melting range of polyacetal polymers decorating these articles. Such articles include tables, by reacting a polyacetal prepolymer having polymeric counter-tops, wall paneling, furniture, and the like. One chains consisting essentially of a major proportion of particular important commercial application in business 45 recurring oxymethylene units and a monoethylenically has been the sublimation printing or marking of busi unsaturated compound in the presence of a free radical ness-machine keyboards. The sublimation dying or yielding compound. printing of plastic materials, however, has not been as U.S. Pat. No. 3,476,832 discloses an oxymethylene readily accomplished as the heat transfer printing of polymer composition with improved impact resistance textile materials. Among the problems which have been 50 and superior flex resistance comprising a blend of a solid found is that the plastics do not readily absorb the dye, oxymethylene polymer and a rubbery polymeric mate the heat required to sublime the dyes also is sufficient to rial such as derived from diolefin-nitrile copolymers, soften the plastic receptor surface, as well as the dye lower alkyl acrylate homopolymers, and copolymers of adhesives on the transfer paper, and the paper and plas lower alkyl acrylates with butadiene, ethylene, vin- tic fuse together. 55 ylethers, acrylonitrile, and the like. U.S. Pat. No. 4,465,728 discloses a heat transfer pro U.S. Pat. No. 3,526,680 discloses improving the im cess which attempts to alleviate some of these problems pact strength of oxymethylene polymers by blending for heat transfer printing thermoplastics which will therewith a copolymer of alpha-olefins and unsaturated absorb sublimable dyes including polycarbonates, vi carboxylic acids, which copolymer contains ions of nyls, acrylics, polystyrene, ABS (acrylonitrile-butadi 60 mono to trivalent metals. Thus, copolymers of ethylene ene-styrene) and like extrudable polymers. and acrylic acid or methacrylic acid which contain U.S. Pat. No. 4,406,662 discloses a process for im alkali metal ions can be used. proving the heat transfer printing of articles molded U.S. Pat. No. 3,704,275 modifies the properties of from filled methyl methacrylate homopolymers and polyoxymethyienes by incorporating therein an inor copolymers of methyl methacrylate with other ethyl- 65 ganic nucleating agent and a polymer which is dis enically unsaturated compounds (e.g., vinyl acetate, persed in the molding composition in the form of parti styrene, alkylacrylates, acrylonitrile, alkylmethacry- cles having a diameter in the range of from 0.1 to 5 lates, multifunctional acrylic monomers such as alkyl- microns. Various modifying polymers are disclosed 4,795,477 34 including numerous olefinically unsaturated com about 5 to about 50 wt. % of an amorphous or partially pounds including alpha-olefins such as polyethylene crystalline polymer. The addition of the amorphous or and ethylene/acrylic acid copolymers among numerous partially crystalline polymer to the oxymethylene poly others. mer improves the penetration of various color inks into U.S. Pat No. 3,850,873 discloses glass fiber-rein- 5 molded articles formed from the composition compared forced polyoxymethylenes exhibiting improved me to molded articles formed from a wholly oxymethylene chanical properties by blending therewith a high molec polymer. Moreover, the modified oxymethylene poly ular weight polyurethane. Polyurethane-modified oxy- mer compositions of this invention can be heat transfer methylene polymer compositions are known to increase printed to yield brighter and sharper printed surfaces the impact strength relative to oxymethylene composi tions without the polyurethane addition. U.S. Pat No. 4,201,849 discloses acetal resin compo sitions which exhibit very small mold shrinkage and 10 compared to unmodified oxymethylene polymers. The compositions are easily moldable and extrudable into articles and maintain the desired physical and mechani mold warping by blending the acetal resin with a petro cal properties of unmodified oxymethylene polymers. leum resin which has been prepared by polymerizing a 15 Thus, while the compositions of the present invention cracked petroleum fraction boiling between --15 and are not novel as compositions, per se, the modified 200 C. and containing unsaturated hydrocarbons. oxymethylene polymer compositions of this invention U.S. Pat. No. 4,277,577 discloses an oxymethylene have unexpectedly improved ability to be printed by the polymer molding composition of improved impact sublimation printing process and thus extend the use of strength comprising a blend of an oxymethylene poly 20 polyacetal resins in various home and business environ mer, an elastomer, and a segmented thermoplastic co- ments where decorated engineering plastics have found polyester or a polyurethane. use. U.S. Pat. No. 4,424,307 discloses an oxymethylene polymer which is modified with 1,2-polybutadiene to enhance the physical properties, including tensile im 25 DESCRIPTION OF PREFERRED EMBODIMENTS pact, elongation and work to break of the oxymethylene The oxymethylene polymer used in the printable polymer. molding composition of the present invention is well Accordingly, while it has been suggested to modify known in the art. The polymers are characterized as oxymethylene polymers by adding thereto various pol having recurring oxymethylene groups or units, i.e., ymeric materials, up until the present time, it has not 30 --CH2O--. The term oxymethylene polymer as used been recognized that polymer additions to oxymethy herein is intended to include any oxymethylene polymer lene polymers can yield thermoplastic molding compo sitions which can be satisfactorily printed by the heat transfer printing process from otherwise substantially unprintable highly crystalline oxymethylene polymer. 35 having --CH2O-- groups comprising at least about 50 percent of the recurring units, for example, homopoly mer, copolymers, terpolymers and the like. Inasmuch as oxymethylene polymers have desirable Typically, the homopolymers are prepared by the physical and mechanical properties including good im polymerization of anhydrous formaldehyde or by the pact strength it would be advantageous to print molded polymerization of trioxane which is a cyclic trimer of articles formed therefrom and increase the use of this formaldehyde. For example, high molecular weight plastic in the home and in the business environment. 40 polyoxymethylenes have been prepared by polymeriz Accordingly, a principle object of the present invention ing trioxane in the presence of certain fluoride catalysts is to improve the printability of oxymethylene polymers such as antimony fluoride and may also be prepared in by the sublimation printing process. Another object of high yields and at rapid reaction rates by the use of the invention is to extend the use of polyacetal resins in catalysts comprising boron fluoride coordinate com various home and business environments where deco 45 plexes with organic compounds, as described in applica rated engineering plastics have found use. tion Ser. No. 691,143, filed Oct. 21, 1957, by Hudgin These and other objects, as well as the scope, nature, and Berardinelli. and utilization of the present invention, will be apparent The homopolymers are usually stabilized against to those skilled in the art from the following description thermal degradation by end-capping or the incorpora and appended claims. 50 tion therein of stabilizer compounds such as described SUMMARY OF THE INVENTION in U.S. Pat. No. 3,133,896 to Dolce and Berardinelli. Oxymethylene polymers that are particularly adapted In accordance with the present invention, there is provided an oxymethylene polymer molding composi tion which is capable of being molded to form articles exhibiting enhanced ability to be printed by the sublima tion printing process. The molding composition of this 55 for use in the molding compositions of the present in vention are oxymethylene copolymers, which may be prepared as described in U.S. Pat. No. 3,027,352 of Walling et al by copolymerizing, for example, trioxane invention comprises an intimate blend of about 50 to with any of various cyclic ethers having at least two about 95 wt. % based upon the total weight of the com adjacent carbon atoms, e.g., ethylene oxide, dioxolane, position of an oxymethylene polymer and from about 5 60 and the like. to about 50 wt. % based upon the total weight of the Especially suitable oxymethylene copolymers which composition of an amorphous or partially crystalline may be used in the molding compositions of the present polymer. invention usually possess a relatively high level of poly Thus, in accordance with the present invention there mer crystallinity, i.e., about 70 to 80 percent. These is provided a process for the sublimation printing of 65 preferred oxymethylene copolymers have repeating molded articles formed from an oxymethylene polymer units which consist essentially of (a) --OCH2-- groups molding composition comprising a blend of about 50 to interspersed with (b) groups represented by the general about 95 wt. % of an oxymethylene polymer and from formula: 4,795,477 56 stantially of oxymethylene and oxyethylene groups in a ratio of from about 6 to 1 to about 1000 to 1. Il O C C (R3)n The oxymethylene copolymers that are preferably present in the molding compositions of the present in Ri Ri 5 vention are thermoplastic materials having a melting point of at least 150* C., and normally are millable or wherein each Ri and R2 is selected from the group processable at a temperature of from about 180* G to consisting of hydrogen, lower alkyl and halogen-sub about 200* G They have a number average molecular stituted lower alkyl radicals, each R3 is selected from weight of at least 10,000. The preferred oxymethylene the group consisting of methylene, oxymethylene, 10 copolymers have an inherent viscosity of at least 1.0 lower alkyl and haloalkyl-substituted methylene, and (measured at 60* G in a 0.1 weight percent solution in lower alkyl and haloalkyl-substituted oxymethylene p-chlorophenol containing 2 weight percent of alphapi- radicals, and n is an integer from zero to three inclusive. nene). Each lower alkyl radical preferably has from one to The oxymethylene copolymer component of the two carbon atoms, inclusive. The --OCH2-- units of (a) 15 molding composition of this invention preferably is an constitute from about 85 to about 99.9 percent of the oxymethylene copolymer that has been preliminarily recurring units. The units of (b) may be incorporated stabilized to a substantial degree. Such stabilizing tech into the copolymer during the step of copolymerization nique may take the form of stabilization by degradation to produce the copolymer by the opening of the ring of of the molecular ends of the polymer chain to a point a cyclic ether having adjacent carbon atoms, i.e., by the 20 where a relatively stable carbon-to-carbon linkage ex breaking of an oxygen-to-carbon linkage. ists at each end. For example, such degradation may be Copolymers of the desired structure may be prepared effected by hydrolysis as disclosed in U.S. Pat. No. by polymerizing trioxane together with from about 0.1 3,219,623 to Berardinelli. to about 15 mole percent of a cyclic ether having at least two adjacent carbon atoms, preferably in the pres 25 If desired, the oxymethylene copolymer may be endcapped by techniques known to those skilled in the art. ence of a catalyst such as a Lewis acid (e.g, BF3, PF5, and the like) or other acids (e.g., HCIO4, 1% H2SO4, and the like). In general, the cyclic ethers employed in making the preferred oxymethylene copolymers are those repre sented by the general formula: 30 A preferred end-capping technique is accomplished by acetylation with acetic anhydride in the presence of sodium acetate catalyst. A preferred oxymethylene copolymer is commercially available from Celanese Corporation under the designation CELCON (ft) acetal copolymer, and especially preferred is CELCON M90 which has a melt index of about 9.0 g/10 min, when tested in accordance with ASTM D1238-82. R1CR2 -- o With respect to the oxymethylene terpolymer, it may R1CR2--(R3)n 35 be prepared, for example, by reacting trioxane and a cyclic ether and/or cyclic acetal such as in the prepara wherein each Ri and R2 is selected from the group consisting of hydrogen, lower alkyl and halogen-sub tion of the oxymethylene copolymer, with a third mon omer which is a bifunctional compound such as a diglycide of the formula: stituted lower alkyl radicals, and each R3 is selected 40 from the group consisting of methylene, oxymethylene, lower alkyl and haloalkyl-substituted methylene, and CH2------ CH--CH2--Z--CH2--CH-------CH2 lower alkyl and haloalkyl-substituted oxymethylene radicals, and n is an integer from zero to three inclusive. o o Each lower alkyl radical preferably has from one to two 45 wherein Z represents a carbon-to-carbon bond, an oxy carbon atoms, inclusive. gen atom, an oxy-alkoxy of 1 to 8 carbon atoms, prefera The preferred cyclic ethers used in the preparation of bly 2 to 4 carbon atoms, and which may be an oxycy- the preferred oxymethylene copolymers are ethylene cloalkoxy of 4 to 8 carbon atoms, or an oxy-poly(lower oxide and 1,3-dioxolane, which may be represented by alkoxy), preferably of 2 to 4 recurring groups each with the formula: 50 1 to 2 carbon atoms, for example, ethylene diglycide, diglycidyl ether and diethers of 2 mols of glycide and 1 Ch2 O mol of formaldehyde, dioxane or trioxane, or diethers of 2 mols of glycide and 1 mol of an aliphatic diol with 2 CH2-(OCH2),, to 8 carbon atoms, advantageously 2 to 4 carbon atoms, 55 or a cycloaliphatic diol with 4 to 8 carbon atoms. wherein n represents an integer from zero to two, inclu Examples of suitable bifunctional compounds include sive. Other cyclic ethers that may be employed are the diglycidyl ethers of ethylene glycol, 1,4-butanediol, 1,3-dioxane, trimethylene oxide, 1,2-propylene oxide, 1,3-butanediol, cyclobutane-1,3-diol, 1,2-propane-diol, 1,2-butylene oxide, 1,3-butylene oxide and 2,2-di- cyclohexane-1, 4-diol and 2-dimethyl-4-dimethyl- (chloromethyl)-1,3-propylene oxide. 60 cyclobutanel,3-diol, with butanediol diglycidyl ethers The preferred catalyst used in preparing the desired being most preferred. oxymethylene copolymers is the aforementioned boron Generally, in preparing the terpolymer of trioxane, trifluoride as discussed in the previously identified cyclic ether and/or cyclic acetal and at least one bifunc Walling et al patent. Reference is made to this patent for tional diglycide compound, a ratio of from 99.89 to 89.0 further information concerning the polymerization con 65 weight percent trioxane, 0.1 to 10 weight percent of the ditions, amount of catalyst employed, and the like. cyclic ether and/or cyclic acetal, and 0.01 to 1 weight The oxymethylene copolymers produced from the percent of the bifunctional compound is preferred, with preferred cyclic ethers have a structure composed sub the percentage figures being based on the total weight 4,795,477 78 of monomers used in forming the terpolymer. The ter- C. for a specified period of time, and then washed with polymers thus obtained are characterized as being es water and dried or centrifuged. sentially white and having a particularly good extrud- A preferred oxymethylene terpolymer is commer ability. cially available from Celanese Corporation under the The polymerization of the terpolymer may be carried 5 designation U10, and is a butanediol diglycidyl ether- out according to known methods, that is in substance, /ethylene oxide/trioxane terpolymer containing about solution or suspension, while using the above-men 0.05 weight percent, 20. weight percent, and 97.95 tioned quantitative proportions of the termonomers. As weight percent of each component, respectively. solvents, there may advantageously be used inert ali It is within the ambit of the present invention to use phatic or aromatic hydrocarbons, halogenated hydro 10 oxymethylene polymers that include, if desired, plasti carbons or ethers. cizers, formaldehyde scavengers, mold lubricants, anti In some cases, it may be advantageous to use the following quantitative proportions: 99.85 to 89.5 weight oxidants, fillers, colorants, reinforcing agents, light sta bilizers, pigments, other stabilizers, and the like, so long percent of trioxane, 0.1 to 10 weight percent of cyclic as such additives do not materially affect the desired ether or cyclic acetal, and 0.05 to O.S weight percent of 15 properties including enhancement of printability of the diglycidyl ether, the percentage figures being calcu resulting molding composition and the articles molded lated on the total weight of the monomer mixture used therefrom. for preparing the terpolymer. Suitable formaldehyde scavengers include cyano- The trioxane-based terpolymer polymerization is guanidine, melamines, polyamides, amine-substituted advantageously carried out at temperatures at which 20 triazines, amidines, ureas, hydroxyl salts of calcium, trioxane does not crystallize out, that is, at a tempera magnesium, and the like, salts of carboxylic acids, and ture within the range of --50* C. to +100* C., depen- metal oxides and hydroxides. Cyanoguanidine is the digg on the solvent used, and in the absence of a solvent preferred formaldehyde scavenger. Suitable mold lubri at a temperature within the range of +20" C. to +100* cants include alkylene bisstearamide, long-chain am C. 25 ides, waxes, oils, and polyether glycides. The preferred As trioxane-based terpolymer polymerization cata mold lubricant is commercially available from Glyco lyst, all substances may be used which are capable of Chemical, Inc. under the designation Acrawax C and is initiating a cationic polymerization, for example, or alkylene bisstearamide. The preferred antioxidants are ganic or inorganic acids, acid halides and, preferably, hindered bisphenols. Especially preferred is 1,6-hex- Lewis acids. Of the latter, boron fluoride and its com 30 amethylene bis-(3,5-di-t-butyl-4-hydroxyhydrocinna- plex compounds, for example, etherates of boron fluo mate), commercially available from Ciba-Geigy Corp. ride, are advantageously used. Diazonium fluoroborates under the designation Irganox 259. are particularly advantageous. The oxymethylene polymer as described hereinabove The concentration of the catalyst may vary within is modified to improve the printability of articles the limits depending on the nature of the catalyst and on 35 molded therefrom by incorporating amorphous or par the intended molecular weight of the terpolymer. The tially crystalline polymers. By the term partially crys concentration of the catalyst may be within the range of talline, it is meant that the polymer have a crystallinity 0.0001 to 1 weight percent, calculated on the total mon which does not exceed 30%. omer mixture, and is advantageously within the range Although, as will be seen, the amorphous or partially of 0.001 to 0.1 weight percent. 40 crystalline polymer can be either normally solid or Since the catalysts tend to decompose the terpoly normally rubbery, the compositions of this invention mer, the catalyst is advantageously neutralized immedi are all normally rigid. Therefore, if the additive poly ately after the polymerization, for example, with ammo mer is rubbery, the maximum amount used is that which nia or methanolic or acetonic amine solutions. ensures that the final composition will be rigid at ordi The unstable terminal hemiacetal groups may be 45 nary temperatures, e.g., about 75*-90" F. removed from the terpolymer in the same manner as The following examples of useful additive polymers known for other oxymethylene polymers. Advanta may be cited: geously, the terpolymer is suspended in aqueous ammo (1) Homo- and copolymers of alpha-olefins, for exam nia at temperature within the range of 100* to 200" C., ple polyethylene, ethylene/propylene copolymers, and if desired, in the presence of a swelling agent such 50 ethylene/acrylic ester copolymers, ethylene/methacry- as methanol or n-propanol. Alternatively, the terpoly lic ester copolymers, ethylene/acrylic acid copolymers. mer is dissolved in an alkaline medium at temperatures Especially suitable are polyethylene or copolymers of above 100* C. and subsequently reprecipitated. Exam ethylene with vinyl acetate, or copolymers of ethylene ples of suitable solvents are benzyl alcohol, ethylene with acrylic esters, preferably the methylacrylic, glycol monoethyl ether or a mixture of 60 weihht per 55 ethylacrylic, butylacrylic or 2-ethylhexylacrylic ester, cent methanol and 40 weight percent water. Examples where the amount of ethylene is from 40 to 90, prefera of suitable compounds having an alkaline reaction are bly 50 to 80 weight %. ammonia and aliphatic amines. (2) Homo- and copolymers of 1,3-dienes having 4 to It is also possible to thermally stabilize the terminal 5 carbon atoms, for example polybutadiene, polyiso- groups of the terpolymers in the absence of a solvent in 60 prene, butadiene/styrene copolymers, butadiene/a the melt in the presence of a stabilizer. crylonitrile copolymers, EPDM rubbers. Alternatively, the terpolymer can be subjected to (3) Homo- and copolymers of vinyl esters, for exam heterogeneous hydrolysis wherein water, with or with ple polyvinyl acetate, polyvinyl propionate, polyvinyl out a catalyst, e.g., an aliphatic or aromatic amine, is butyrate. added to a melt of the terpolymer in an amount ranging 65 (4) Homo- and copolymers of acrylic and meth- from about 1 to about 50 percent based on the weight of acrylic esters, for example polyethylacrylate, the terpolymer. The terpolymer mixture is maintained polybutylacrylate, poly-2-ethylhexylmethacrylate, po- at a temperature in the range of from about 170" to 250 lyoctylmethacrylate. 4,795,477 9 10 (5) Polyurethanes, for example polyester and poly- 2,914,556. A particularly preferred polyester diol is that ether types. obtained by initiating the polymerization of e-caprolac- (6) Polyphenylene ethers, such as poly(2,6-dimethyl- tone with 1,4-butanediol. 1,4-phenylene)ether. The polyether polyols employed in the preparation of (7) Polysulfones, such as the condensation product of 5 the polyurethane elastomers of the invention include bisphenol-A and 4,4'-dichlorodiphenyl sulfone. the polyether glycols having molecular weights in the (8) Polyamides, such as polycaprolactam, or the above defined range and prepared by reacting ethylene product of hexamethylenediamine and adipic acid. oxide, propylene oxide, butylene oxide, or mixtures (9) Polyimides, e.g., the product of bismaleimido thereof with water or with diols such as ethylene gly diphenyl methane and methylene dianiline. 10 col, 1,2-propylene glycol, 1,3-propanediol 1,4- (10) Normally solid or normally rubbery polyor- butanediol, 2,3-butanediol, 1,5-pentanediol, 1,2-hex- ganosiloxanes, such as polyalkyl or aryl-siloxanes, or anediol, diethanolamine, resorcinol, catechol, bis(p- combinations of the two, and copolymers of polyor- hydroxyphenyl) methane, diethylene glycol, dipropyl ganosiloxanes with vinyl aromatics, e.g. styrene; acrylic ene glycol, and the like. monomers, e.g., methyl methacrylate; or aromatic es 15 The extenders which are employed in preparing the ters, e.g., the reaction products of bisphenol-A and iso polyurethane elastomers of the invention can be any of or terephthaloyl chloride; as well as siloxane-nitrogen the diol extenders commonly employed in the art. illus copolymers containing amido, amide-imido and imide trative of diol extenders are aliphatic diols, advanta groups. geously containing from 2 to 6 carbon atoms, inclusive, All such polymers are either commercially available 20 such as ethylene glycol, 1,3-propylene glycol, 1,2-pro- or can be made in ways known to those skilled in the pylene glycol, 1,4-butanediol, 1,2-hexanediol, neopentyl art. glycol, and the like; and dihydroxyalkylated aromatic A particularly preferred amorphous polymer for compounds such as the bis(2-hydroxyethyl)ethers of modifying the printability oxymethylene polymer is an hydroquinone and resorcinol; p-xylene-a,a'-diol; the elastic polyurethane. Useful elastomeric polyurethane 25 bis(2-hydroxyethyl)ether of p-xylene-a,a'-diol; m- are those which have been prepared from polyester xylene-a,a'-diol and the bis(2-hydroxyethyl)ether polyols, polyether polyols such as polyethylene-glycol thereof. ethers, polypropyleneglycol ethers or polyacetals hav The organic diisocyanate employed in the process of ing free hydroxyl end groups and polyisocyanates, in the invention can be any of those commonly employed particular diisocyanates, using chain-extending agents 30 in the preparation of polyurethane elastomers. Illustra such as low molecular weight polyols, preferably gly tive of said diisocyanates are 2,4-tolylenediisocyanate, cols. 2,6-tolylene diisocyanate, 4,4'-methylenebis(phenyl iso The polymeric polyols and polyol extenders which cyanate), 3,3'-dimethyl-4,4'-diisocyanatodiphenyl, 3,3'- can be used are those conventionally employed in the dimethoxy-4,4'-diisocyanatodiphenyl, 3,3'-dichloro- art for the preparation of such elastomers. The poly 35 4,4'-diisocyanatodiphenyl, /3,/3'-diisocyanato-1,4-dieth- meric polyols are preferably polymeric diols which ylbenzene, 1,5-naphthalene diisocyanate, 1,4-phenylene advantageously have molecular weights in the range of diisocyanate, and the like, including mixtures of two or 400 to 4000 and preferably within the range of about 500 more of the above diisocyanates. The preferred diisocy to about 3000. Illustrative of polymeric diols are polyes anate is 4,4'-methylenebis(phenyl isocyanate). ter diols and polyether diols and mixtures thereof hav 40 The elastomeric polyurethanes which are useful in ing molecular weights within the above range. The the present invention can be prepared by processes polyester diols include the essentially linear polymeric which are conventional in the art for the synthesis of diols which are obtained by esterification of an aliphatic thermoplastic polyurethanes. Illustrative of such pro or aromatic dibasic acid or anhydride with a glycol. cesses are those described in U.S. Pat. Nos. 3,493,364; Preferably the glycol is employed in excess of the stoi 45 4,169,196; 4,202,957; and 3,642,964. Such processes in chiometric proportion with respect to the acid or anhy clude the one-shot procedure in which all of the reac dride in order to ensure that the polyesters are hydrox tants are brought together simultaneously, and the pre yl-terminated. Representative dicarboxylic acids (or polymer procedure in which the isocyanate is reacted their anhydrides) employed in the preparation of the with the polyester or polyether glycol in a first-step and polyester diols are adipic, succinic, pimelic, suberic, 50 the isocyanate-terminated prepolymer so produced is azelaic, sebacic, terephthalic, phthalic, and the like subsequently reacted with the diol extender. The one- acids or their anhydrides or mixtures of two or more of shot process also includes the process in which the said acids or anhydrides. Adipic acid is the preferred diisocyanate has been converted to a quasiprepolymer acid. Representative glycols employed in the prepara by reaction with a minor amount (i.e., less than about tion of the polyester diols are the straight chain aliphatic 55 10% on an equivalent basis) of the glycol prior to carry glycols containing from 2 to 10 carbon atoms, inclusive, ing out the polyurethane-forming reaction. such as ethylene glycol, propane-1,3-diol, butane-1,4- If desired, the elastomeric polyurethanes or any of diol, 2-butene- 1,4-diol, hexane-1,6-diol, octane-1,8-diol, amorphous or partially crystalline polymers of the pres decane-1,10-diol, and the like, or mixtures of two or ent invention can have incorporated in them, at any more such glycols. 60 appropriate stage of preparation, additives such as pig In addition to the above type of polyester diols, there ments, fillers, lubricants, stabilizers, antioxidants, color can also be used the polycaprolactone diols which are ing agents, fire retardants, and the like, which are com prepared by polymerizing the appropriate caprolactone monly used in conjunction with such polymers. with the appropriate difunctional initiator, such as an The printable oxymethylene polymer molding com aliphatic glycol as exemplified above or an alkanola- 65 position of the present invention comprise from about 5 mine such as ethanolamine, propanolamine, butanola- to about 50 weight percent, preferably from about 10 to mine, and the like. Such procedures and products are about 50 weight percent, and most preferably from well-known in the art; see, for example, U.S. Pat. No. about 10 to about 40 weight percent of the amorphous 4,795,477 11 12 or partially crystalline polymeric additive. Correspond of printing the molded articles formed from the compo ingly, from about 50 to about 95 weight percent, prefer sition of the present invention. ably from about 50 to about 90 weight percent, and Thus, the dye transfer or carrier sheet can be any of most preferably from about 60 to about 90 weight per the numerous dye imprinted webs including paper, cent of the oxymethylene polymer is present. The above metal foil, or plastic film, including those numerous weight percents are based on the total weight of the molding composition. papers in use in transferring dyes and dye patterns in the fabric and textile industry. The molding compositions may suitably be prepared The dyes can be of various dyes, including disperse by any conventional procedure that will result in an dyes, capable of sublimation of 200 F. and up, includ intimate blend or mixture of the components. Prefera 10 ing those dyes in use on heat transfer papers on dye bly, dry or melt blending procedures and equipment are transfer in the textile industry. used. For example, the amorphous polymer (in the form The temperatures necessary to effect dye transfer and of pellets, chips, or granules) can be dry mixed with the absorption in the present invention have been found to oxymethylene polymer (in the form of pellets, chips, be governed by the temperatures required for dye subli granules or powder) typically at room temperatures, 15 mation and the temperatures at which the dye receptor and the resulting mixture melt blended in any conven surface energy level rises to become susceptible to dye tional type extrusion equipment, which is heated to a penetration, which can be at or below the softening temperature of from about 180* C. to about 230 C., and temperatures therefore. These temperatures have been preferably from about 185 C. to about 205 C. found to be above about 250 F. for the compositions of Preferably, the polymeric additive and oxymethylene 20 the present invention, with te'mperatures above 300 F. polymer are dried (either alone or together) before bebg preferred. After the dye transfer is completed, the being subjected to the intimate blending procedure. The materials are cooled below the plastic softening temper drying can be done in desiccated air having a dew point atures, if necessary, and the applied pressure released of about --30 C. to --40* C. or lower, at a temperature of from about 70 C. to about 110 C., and preferably above 80 C. The drying can also be accomplished in a vacuum oven, for example, at a temperature above about 90 C. The drying time will depend primarily on the moisture content, drying temperature, and particu lar equipment employed, but typically is from about 2 to 25 30 and the intermediate carrier separated from the printed surface. The applied pressures necessary to effect dye transfer and absorption will generally be above about 25 psi, but, typically will range from about 50 to 3,000 psi, with about 50 to 500 psi being preferred. The duration of the application of heat and pressure about 6 hours or more. If the drying is conducted for while the printed transfer sheet is an intimate contact longer period of time, such as overnight, the drying with the article to be printed will vary, although, times temperature should preferably be about 70 C. to about of between 30 and 50 seconds are typical. 85 C. In general, any conventional drying procedure The following examples are given to illustrate the can be used to reduce the moisture content to below 35 present invention in more detail. It should be noted that about 0.1 weight percent, based on the total weight of the molding composition, preferably below about 0.05 the invention is in no way to be construed as being strictly limited to these examples. weight percent, and most preferably below about 0.01 EXAMPLE 1 weight percent or lower. As is well known to those skilled in the art, water will react with polyurethanes 40 Two disks formed from oxymethylene polymer com upon processing the polyurethanes at elevated tempera positions were printed with color patterns and the depth tures and, thus, the water content of the composition of dye penetration was measured. The control disk was must be extremely small where polyurethane polymers formed from Celcon M90-04 which is a stabilized are used. acetal copolymer having a melt index of about 9.0 g/10 The oxymethylene molding composition resulting 45 min. marketed by Celanese Corporation. A second disk from the intimate blending procedure is then commi was molded from the same acetal copolymer containing nuted mechanically, for example by chopping, pelletiz an additional 20% by weight of an elastomeric polyes ing or grinding, into granules, pellets, chips, flakes or ter-based polyurethane. The compositions were molded powders, and processed in the thermoplastic state, for into two inch disks. The disks were printed by transfer example by injection molding or extrusion molding, 50 ring the color patterns from paper by intimately con into shaped articles, for example, bars, rods, plates, tacting the paper transfer sheet and the polyacetal disks sheets, films, ribbons, tubes and the like. at a temperature of 350 F., a pressure of 85 psi for a Preferably, the comminuted oxymethylene molding dwell time of 40 seconds. Portions of the disk contain composition is dried (as discussed above) prior to being ing the dye area were cut, embedded in epoxy and pol molded. 55 ished down to 1 micron with AI2O3 powder paste. The In general, molded articles formed from the molding polished cross sections were examined in an optical composition of the present invention can be decorated, microscope with oblique incidental light. Representa printed, dyed, etc. by any conventional heat transfer tive micrographs at 100X were taken from red and process technique. Typically, such process involves green dye areas. printing an intermediate or carrier sheet with the de 60 Dye penetrations were found to be deeper and more sired pattern with a sublimable disperse dye and bring uniform in the sample containing the 20% by wt. poly ing into intimate contact the printed surface of the car urethane. The average depth was around 80 microns. rier and the surface of the molded article which is to Dye penetration was less uniform in the control. Al receive the dye. Sufficient heat and pressure are applied though the dyes were found to penetrate to a depth of to sublime the dye and cause diffusion of the gaseous 65 70 microns, the higher concentration region extends to dye into the substrate wherein the decorative pattern or around 40 microns. The measurements of dye penetra the like is permanently adhered. Any of the known dye tion in the samples are estimations made from the micro carriers and sublimable dyes can be used in the process graphs. The estimations were made difficult because of 4,795,477 13 14 the nature of diffuse boundaries between the dyed and undyed areas. EXAMPLE 2 II -0-C-C-(R3),, Eight disks formed from oxymethylene polymer 5 R, Rj compositions were printed with black letters and the depth of black dye penetration was measured. Three control disks comprising various oxymethylene copoly mers without polymeric addition were tested. Control 10 A was the same acetal copolymer utilized in Example 1. Control B is a similar acetal copolymer having a melt index of 9.0 g/10 min. but containing a different stabi lizer than Control A. Control C comprises the same acetal copolymer as Control A but also containing 0.5 15 wt. % of a branched acetal terpolymer. The composi tions were molded into disks, printed and the dye pene tration measured as in Example 1. Again the measure ments are estimations made from the micrographs in 20 which diffuse boundaries between dyed and undyed wherein each Ri and R2 is selected from the group consisting of hydrogen, lower alkyl and halogensubstituted lower alkyl radicals, each R3 is selected from the group consisting of methylene, oxymethy lene, lower alkyl and halo-alkyl-substituted methy lene, and lower alkyl and haloalkyl-substituted oxymethylene radicals and n is an integer from 0 to 3, inclusive, each lower alkyl radical having from 1 to 2 carbon atoms, inclusive, said copolymer hav ing a number average molecular weight of at least 10,000 and a melting point of at least 150* C., and (iii) oxymethylene terpolymer, which is the reaction product of trioxane, a cyclic ether and/or cyclic acetal, and a diglycide of the formula: areas made exact determinations of dye penetrations impractical. Table 1 summarizes the results which were CHj----- CH--CH2--Z--CH2--CH------CH2 obtained. oo As can be seen, the polyacetal molding composition 25 containing the polyethylene ethylacrylate copolymer wherein Z is selected from the group consisting of and the EPDM rubber additives improve the dye pene a carbon-to-carbon bond, oxygen, an oxyalkoxy of tration relative to Control C. The multiphase interpoly mer did not improve dye penetration. 30 1 to 8 carbon atoms, and an oxypoly (lower alkoxy). 3. The process of claim 1 wherein said dye is a dis TABLE 1 persed sublimable dye. Depth of dve penetration in Celcon Disks 4. The process of claim 2 wherein said oxymethylene Sample I.D. Description Penetration Depth of Black Dye polymer is said oxymethylene copolymer. 5. The process of claim 4 wherein said oxymethylene A Stabilized acetal copolymer B Stabilized acetal copolymer 90 microns 100 microns 35 copolymer has a melt index of 9.0 g/10 min. 6. The process of claim 1 wherein said polymer addi C Stabilized acetal copolymer 90 microns tive is an elastomeric polyurethane. containing 0.S wt. % branched 7. The process of claim 6 wherein said molding com acetal terpolymer position contains 10% by wt of said elastomeric poly D C plus 5 wt. % polyethylene 105 microns 40 urethane. ethylacrylate E C plus 10 wt % polyethylene ethylacrylate F C plus 5 wt % KM3301 G C plus 10 wt % KM330 H C plus 5 wt. % EPDM-b&sed 110 microns 90 microns 65 microns 100 microns 8. The process of claim 6 wherein said molding com position contains 20% by wt. of said elastomeric poly urethane. 9. The process of claim 1 wherein said polymer addi 45 tive is a copolymer of ethylene and alkylacrylate. rubber2 10. The process of claim 9 wherein said polymer 'A multiphase interpolymer comprising an acrylic elastomeric phase and a rigid IbermopUitic phase manufactured by Rohm and Haas, Philadelphia, Pa. additive comprises at least about 40 to 90 wt % ethyl ene. ^Ethylene propylene-diene terpolymer end capped with maleic anhydride. 11. The process of claim 10 wherein said alkylacry 50 late is ethylacrylate. What is claimed is: 12. The process of claim 10 wherein said alkylacry 1. A process for transferring a dye from a intermedi late is butylacrylate. ate transfer surface to an article molded from an oxy 13. The process of claim 1 wherein said polymer methylene polymer, comprising; intimately contacting additive is a 1,3-diene rubber. said intermediate transfer surface with said molded 55 14. The process of claim 13 wherein said rubber is an article and applying sufficient heat and pressure to ethylene-propylene-diene terpolymer end-capped with transfer the dye from said transfer surface to said maleic anhydride. molded article, said molded article being formed from a 15. A process for transferring a dye from a intermedi blend of about 50 to 90 wt. % of an oxymethylene poly ate transfer surface to an article molded from an oxy mer and from about 10 to 50 wt. % of an amorphous or partially crystalline polymer additive. 60 methylene polymer, comprising; intimately contacting said intermediate transfer surface with said molded article and applying sufficient heat and pressure to 2. The process of claim 1 wherein the oxymethylene transfer the dye from said transfer surface to said polymer is selected from the group consisting of: molded article, said molded article being formed from a (i) oxymethylene homopolymer, 65 blend of a major amount of oxymethylene polymer and (ii) oxymethylene copolymer comprising about 85 to at least about a sufficient minor amount of an amor about 99.9 percent recurring --OCHz-- groups phous or partially crystalline polymer additive to im interspersed with groups of the formula: prove dye penetration. 4,795,477 15 16 16. The process of claim 15 wherein the oxymethy- ing a number average molecular weight of at least lene polymer is selected from the group consisting of: 10,000 and a melting point of at least 150* C., and 0) oxymethylene homopolymer, (iii) oxymethylene terpolymer, which is the reaction (ii) oxymethylene copolymer comprising about 85 to about 99.9 percent recurring --OCH2-- groups 5 product of trioxane, a cyclic ether and/or cyclic acetal, and a diglycide of the formula: interspersed with groups of the formula: ch2--ch--ch2--z--ch2--ch--ch2 \/ o \/ o Ri Ri 10 wherein Z is selected from the group consisting of a carbon-to-carbon bond, oxygen, an oxyalkoxy of 1 to 8 carbon atoms, and an oxypoly (lower alk- wherein each Ri and R2 is selected from the group oxy). consisting of hydrogen, lower alkyl and halogen- 15 17. The process of claim 15 wherein said polymer substituted lower alkyl radicals, each R3 is selected additive is an elastomeric polyurethane. from the group consisting of methylene, oxymethy 18. The process of claim 15 wherein said polymer lene, lower alkyl and halo-alkyl-substituted methy additive is a copolymer of ethylene and alkylacrylate. lene, and lower alkyl and haloalkyl-substituted 19. The process of claim 15 wherein said polymer is oxymethylene radicals and n is an integer from 0 to 20 an ethylene-propylene-diene terpolymer end-capped 3, inclusive, each lower alkyl radical having from 1 to 2 carbon atoms, inclusive, said copolymer hav- with maleic anhydrid*e.**** 25 30 35 40 45 50 55 60 65