Document J3r8M6M45rvLe93ek7GEMm3vX

United States Patent [19] Takahashi [ii] Patent Number: [45] Date of Patent: 4,966,935 Oct. 30, 1990 [54] NON-FLAMMABLE POLYBUTYLENE THEREPHTHALATE COMPOSITION [75] Inventor: Katsnhiko Takahashi, Fuji, Japan [73] Assignee: Polyplastics Co.,Ltd., Osaka, Japan [21] Appl. No.: 364,514 [22] Filed: Jun. 9,1989 Related U.S. Application Data [63] Continuation ofSer. No. 106,967, Oct 13, 1987, aban doned, which is a continuation of Ser. No. 774,259, Sep. 10, 1985, abandoned. [30] Foreign Application Priority Data Sep. 10, 1984 [JP] Japan ........................... 59-189249 [51] Int Cl.5..............................................C08K 3/22 [52] U.S. CL.................................. 524/412; 524/411; 524/605 [58] Field of Search............... 524/410, 411, 412, 605 [56] References Cited U.S. PATENT DOCUMENTS 3,560,441 2/1971 Schwarcz et al......... ....... 524/411 3,751,396 8/1973 Gall....................... ....... 524/371 3,855,277 12/1974 Fox........................ ....... 524/410 3,898,194 8/1975 Sanroma ................ ....... 524/411 4,044,073 8/1977 Baron et al............... ....... 524/412 4,257,937 3/1981 Cohen et al.............. ....... 525/439 FOREIGN PATENT DOCUMENTS 1494929 3/1969 Fed. Rep. of Germany . 2417663 10/1974 Fed. Rep. of Germany . 2512504 10/1976 Fed. Rep. of Germany . 1373774 11/1974 United Kingdom . 2108969 5/1983 United Kingdom . OTHER PUBLICATIONS Fillers for Plastics-pp. 8 and 9, (1971)--William Wake, editor, ILIFFE Books, London. Patent Abstracts of Japan, vol. 8, No. 34, Feb. 15,1984, Appln. No. 58-198543, (Kanegafuchi Kagaku Kogyo KK, 11/18/83). Patent Abstracts ofJapan, vol. 8, No. 212, Sep. 27,1984, Appln. No. 57-205396, (Teijin KK, 6/2/84). Primary Examiner--Veronica P. Hoke Attorney, Agent, or Firm--Bums, Doane, Swecker & Mathis [57] ABSTRACT A polybutylene terephthalate composition comprises (A) polybutylene terephthalate, (B) a flame retardant and (C) a flame-retarding assistant of antimony trioxide having an average particle size of 1 micron or larger and eventually is improved in the flame-retarding property and stability when it melts. 7 Claims, No Drawings 4,966,935 12 ene terephthalate compound having polycarbonate NON-FLAMMABLE POLYBUTYLENE blended therein, however, it has been found that its melt THEREPHTHALATE COMPOSITION stability is remarkably low due to the effect of the anti mony trioxide used therein as a flame retarding assis This application is a continuation of application Ser. 5 tant. No. 106,967, filed Oct. 13, 1987, now abandoned, which is a continuation of application Ser. No. 774,259, filed Solution to the Problem, and Effect Thereof Sept. 10, 1985, now abandoned. Various experiments were made by the present inven The present invention relates to a nonflammable tors in order to improve the melt stability of such non polybutylene terephthalate compound having im 10 flammable polybutylene terephthalate compound as proved melt stability characteristics. More specifically, aforementioned wherein antimony trioxide is used as a the invention relates to a flame-retarded polybutylene flame retarding assistant, and more particularly of such terephthalate compound having antimony trioxide used nonflammable polybutylene terephthalate compound as a flame retarding assistant, wherein the compound less liable to deformation and having a reinforcer, such has improved melt stability without detriment to its 15 as glass fiber or the like, and polycarbonate blended flame retardancy and other properties, and in particular therein. As a consequence, it was found that the use of to a polyblend compound of polybutylene terephthalate antimony trioxide particles having a mean diameter of 1 having polycarbonate and the like blended therein. pm or more, instead of such finer antimony trioxide Prior Art particles having a mean diameter of less than 1 pm, e.g. 20 0.5 pm, as conventionally used, would result in remark Thermoplastic polyalkylene terephthalate resins, as able improvement of the melt stability of a nonflamma engineering plastics, are used in a wide range of applica ble polybutylene terephthalate compound of the afore tions because of their excellent mechanical and electri cal properties and good molding characteristics. Above all, polybutylene terephthalate is widely used at present, since it is able to crystallize at a faster rate and does not particularly require any nucleating agent for accelerat ing its crystallization. Because of the fact that polybutylene terephthalate is 25 said type without detriment to other properties thereof. This finding led to the present invention. Accordingly, the invention provides a nonflammable polybutylene terephthalate compound having a flame retardant and a flame retarding assistant blended with polybutylene terephthalate, characterized in that an flammable, however, flame retardation thereof is strongly demanded where the material is used for elec 30 antimony trioxide having a mean particle diameter of 1 pm or more is used as a flame retarding assistant. trical parts or the like. Therefore, in the production of a In the invention, the term "polybutylene terephthal nonflammable polybutylene terephthalate, it is a general ate" means a polyester obtained by condensation of practice that a flame retardant and a flame retarding 1,4-butanediol and terephthalic acid, which may be a assistant are added to and blended with polybutylene 35 copolymer or mixture consisting principally of polybu terephthalate. Antimony trioxide is most commonly tylene terephthalate. used as a flame retarding assistant. Where such flame A flame retardant used for the purpose of the inven retardant and such flame retarding assistant are so tion is any organic halogen compound or phosphorus added and blended, it is conventionally required that, in compound generally used as such. More specifically, order to prevent the additives from affecting the prop 40 any aromatic bromine compound is preferred, which erties of a molded part, such as tensile strength, impact more concretely may be such low-molecular weight resistance, and the like mechanical strength, their parti compound as bromine 5--10 substituted compound of cle size should be as small as possible so that their com diphenyl ether or bromine 5--10 substituted compound patibility and dispersibility in the resin may be en of aromatic ring of ethylene glycol diphenyl ether, or a hanced. For this reason, any antimony trioxide conven 45 bromide of a monomer or polymer of any aromatic tionally used as a flame retarding assistant is of such fine carbonate or epoxy compound derived from bisphenol particle diameter as less than 1 fim, e.g. 0.5 pun. A or the like, or a bromide of any polystyrene oligomer, or a brominated cyanurate compound. Problem to be Solved by the Invention For the purpose of the present invention, one or more However, any known nonflammable polybutylene 50 kinds of such flame retardants may be used for blending terephthalate compound in which antimony trioxide is with other component materials. used as a flame retarding assistant has a difficulty that The addition of a flame retardant is preferably limited the greater its antimony trioxide content, the less satis to as small a quantity as possible, because an excessive factory is its melt stability, which means reduced me addition thereof may have an unfavorable effect on the chanical strength where a long-time detention in a 55 mechanical properties of the compound of the inven molder is involved. tion. The quantity of such addition is generally 1 -- 30% Where polybutylene terephthalate is used in those by weight relative to the compound as a whole, and areas of application in which high mechanical strength preferably 2--20% by weight and rigidity are required, it is used in the form of a Any antimony trioxide used for the purpose of the compound containing a reinforcer such as glass fiber or 60 invention must have a mean particle diameter of 1 pun the like. Generally, a polybutylene terephthalate com or more, and preferably of 2 fim or more. A mean parti pound containing a fibrous reinforcer such as glass fiber cle diameter range of 5--7 pun is most preferred. or the like is quite anisotropic and, therefore, it has a A system in which antimony trioxide and polycar drawback that a molding of the compound is liable to bonate are present together is generally subject to no deformation while in process of molding or when an 65 ticeable deterioration through heating and melting. It is nealed. It is known to use polycarbonate in combination assumed that this may be attributable to the fact that with polybutylene terephthalate in order to prevent catalytic effect of the antimony trioxide accelerates the such deformation. With such nonflammable polybutyl decomposition of the polycarbonate and further causes 4,966,935 34 ester exchange reactions thereof with the polybutylene strength and impact strength in particular, and to pro terephthalate. vide good dimensional accuracy, with less possibility of The present inventors assumed that these reactions warping, it is more advantageous to use such filler in should take place on solid surfaces of the antimony combination with a fibrous reinforcing filler. However, trioxide, and in order to reduce the surface area thereof, 5 an excessive addition of reinforcing fillers may have an they considered the use of an antimony trioxide having unfavorable effect on the moldability of the compound. a larger particle diameter. As a result, it was found that From a practical point of view, therefore, the upper by using antimony trioxide particles having a mean limit of such addition, as a total quantity of lamellar and diameter of 1 /xm or more, in place of such finer anti fibrous reinforcing fillers, should be 60% by weight. mony troxide particles having a mean diameter of less 10 More preferably, such limit is 20~50% by weight. than 1 fim, e.g. 0.5 ^im, as conventionally used, would it Among the various reinforcing fillers, specifically be possible to improve the melt stability significantly, or preferred are one or more kinds of reinforcing fillers to a level where it may involve practically no problem, selected from the group consisting of glass fiber, glass in a system in which polycarbonate is present in con flake, and mica. junction with the antimony tiioxide. Furthermore, it 15 The compound according to the invention may con was found that the use of an antimony trioxide having tain a particulate additive to the extent that such content such large particle diameter caused practically no dete is not so detrimental to the moldability of the com rioration in the mechanical properties. In addition, it pound. The term "particulate additive" used herein was found equal in flame retarding effect to the conven means any of the following: glass bead, calcium carbon tional type. 20 ate, ground quartz, silica, magnesium carbonate, cal The quantity of antimony trioxide used in accordance cium sulfate, clay, diatomaceous earth, alumina, silica with the invention, is 1 --15% by weight relative to the compound as a whole, and preferably it is 2~10% by weight. Polycarbonate as used for the purpose of the inven tion refers to a bisphenol-type polycarbonate, which may be obtained, for example, by causing bisphenol with carbonate or by causing phosgene to act on bisphe nol in the presence of alkali. For the purpose of the 25 sand, glass power, metallic particle, and graphite. These particulate materials may be added for reducing the usage of lamellar reinforcing fillers, and also for provid ing any additional function. The aforesaid reinforcing fillers and additives may be advantageously used after they are surface-treated with a suitable surface treating agent, whereby further im invention, polycarbonate is preferably of highflow type 30 provement in mechanical properties can be effected. wherever possible, and the addition thereof is 0.5 ~ 40% Various known surface treating agents may be used for by weight relative to the polybutylene terephthalate. the purpose of the present invention. Among such More particularly, an addition of 1--20% by weight is agents are, for example, silane-based, titanate-based, and preferred. Any excessive addition thereof may have an epoxy-based ones. unfavorable effect on the heat resistance of the com 35 In order to provide the compound of the invention pound. with different characteristics according as required for According to the invention, by using an antimony each specific purpose, it is also possible to incorporate trioxide having a large particle diameter as a flame retarding assistant in such nonflammable polybutylene by addition into the compound one or more of the fol lowing: known additives such as lubricant, nucleating compound having polycarbonate blended therein and 40 agent, release agent, antistatic agent, other surface-ac less liable to deformation, it is possible to improve the tive agent, plasticizer, pigment, dye, heat stabilizer, and melt stability of a system with which the polycarbonate ultraviolet stabilizer; high-polymeric organic sub is present, and to reduce possible deterioration of the stances, such as vinyl compounds and their copolymers, resin compound due to the detention thereof in a mold including aforesaid polycarbonate, low-molecular ing machine. 45 weight polyethylene, polypropylene, polyethylene tere Into the compound of the invention may be incorpo phthalate, polyurethane, fluoroplastics, ethylene-vinyl rated by blending one or more kinds of the following as acetate copolymer, ethylene-alkyl alkylate copolymer, reinforcing fillers: fibrous reinforcing fillers, including styrene-butadiene-acrylonitrile copolymer, and styrene- various inorganic fibers, such as glass fiber, carbon acrylonitrile copolymer, polyphase graft copolymer fiber, graphite fiber, metallic fiber, silicon carbide fiber, 50 consisting of polyacrylate, and thermoplastic segment- asbestos, woliastonite, and fibrous potassium titanate, type copolyester. whisker, and various organic fibers; and lamellar rein The compound in accordance with the invention can forcing fillers, such as micas (musovite, phlogopite, easily be prepared by any known method generally sericite, and the like), lamellar glass (glass flake), talc, employed in preparing a similar resin compound of the and metallic foil. 55 conventional type. Among the methods available for These reinforcing fillers may be used according as the purpose are, for example, one in which components, required for various purposes, such as reinforcement of after blended, are incorporated and extruded by an mechanical properties, provision of electrical conduc extruder into pellets, which are then molded into shape, tivity, prevention of deformation, improvement of fric one such that pellets of different compositions are first tion characteristics, and improvement of flame retard- 60 prepared, which are then blended in the predetermined ancy. proportions, the blend being molded into a part having Especially for the purpose of preventing deformation the desired composition, and one wherein one or more through blending of a reinforcing filler, it is desirable to components are loaded directly into the molding ma use a lamellar reinforcing filler, such as mica or glass chine. flake. 65 A lamellar reinforcing filler will serve effectively to Examples prevent deformation if it is added alone. Yet, in order to To further illustrate the invention, the following ex secure a high level of mechanical properties tensile amples are given. It is to be understood, however, that 4,966,935 56 the scope of the invention is not limited by these exam blender, and then the blend was melted and kneaded by ples. employing a 40 mm single-screw extruder, being thus Methods employed in measuring various properties made into a pellet-form compound. The pellet was referred to in the examples are as follows: molded into a test specimen by using an injection (1) Method of measurement for mean particle diame- 5 molder. The specimen was tested for measurement of its ter of antimony trioxide heat stability and mechanical properties. Measurement was made first of a specific surface area For comparison purposes, a specimen using a conven by gas permeability tests and adsorption method (BET tional antimony trioxide with a mean particle diameter method). From the specific surface area value was cal of 0.5 pm was prepared in similar manner, and tested for culated a specific surface diameter, which was taken as 10 measurement. Test results are shown in Tables 1 and 2. a mean particle diameter. TABLE-1 Component/Property Polybutylene terephthalate Polycarbonate Polycarbonate bromide (flame retardant) Antimony trioxide Particle diameter of antimony trioxide Glass fiber Asbestos Glass flake Mica Tensile strength Tensile elongation Izod impact strength (notched) Hot stability Tensile strength (retention) Tensile elongation (retention) Method of measurement ASTM D 638 " ASTM D 256 Unit wt % " " fxm wt % " Kg/cm2 % Kg cm/cm Example 1 46 4 10 4.3 1 12 4 20 -- 1135 2.0 4.6 Example 2 46 4 10 4.1 6 12 4 20 -- 1105 2.0 4.4 Comp. Example 1 46 4 10 4*2 0.5 12 4 20 -- 1123 2.0 4.9 Example 3 46 4 10 4.1 6 12 4 -- 20 1052 1.7 4.2 Comp. Example 2 46 4 10 4*2 0.5 12 4 -- 20 1063 1.7 4.3 ASTM D 638 Kg/cm2, (%) " %, (%) 908 (80) 1.2 (60) 970 (88) 1.3 (65) 784 (70) 1.0 (50) 968 (92) 1.2 (68) 765 (72) 0.90(53) l Produced by Nihon Mining A Concentrating Co.; trade name "PATOX L" 2CooventjooaJ ^Produced by Nihon Mining A Concentrating Co.; trade name "PATOX M" TABLE-2 Component/Property Method of measurement Unit Example 4 Polybutylene terephthalate Polycarbonate Polycarbonate bromide (flame retardant) Antimony trioxide Particle diameter of antimony trioxide Glass fiber Asbestos Glass flake Mica Tensile strength Tensile elongation Izod impact strength (notched) Hot stability Tensile strength (retention) Tensile elongation (retention) wt % " " ASTM D 638 " ASTM D 256 wt % " " " Kg/cm2 % Kg cm/cm 70 4 15 7*1 6 _ 4 -- -- 610 65 3.1 ASTM D 638 Kg/cm2, (%) 580 (95) " % , (%) 42 (65) *'Produced by Nihon Mining A Concentrating Co.; trade name "PATOX-L" ^Conventional Comp. Example 3 70 4 15 7*2 0.5 _ 4 -- -- 615 67 3.0 418 (68) 35 (52) Example 5 48 4 10 4*1 6 30 4 -- -- 1340 2.5 7.5 Comp. Example 4 48 4 10 4*2 0.5 30 4 -- -- 1335 2.5 7.5 1206 (90) 988 (74) 1.6 (63) 1.3 (52) (2) Heat stability 55 After detained in a molding machine (250 C. X30 The embodiments of the invention in which an exclu min), pellets representing individual compounds were sive property or privilege is claimed are defined as molded into tensile specimens by conventional proce follows: dure. The specimens were tested for measurement of 1. A polybutylene terephthalate composition which their tensile elongation (ASTM D 638). 60 comprises (A) polybutylene terephthalate, (B) a flame Examples 1 -- 5, and Comparative Examples 1~4 retardant, (C) a flame-retarding assistant of antimony trioxide having an average particle size of 1-7 microns Polybutylene terephthalate (produced by polyplas (D) polycarbonate, and (E) a reinforcing filler selected tics Co.; trade name "Juranex 2002") was added with a from the group consisting of glass flake, glass fiber and fire retardant, an antimony trioxide having a mean parti 65 mica. cle diameter of 1 pm or 6 pm, polycarbonate, and vari 2. A polybutylene terephthalate composition as ous reinforcing fillers, as indicated in Tables 1 and 2. claimed in claim 1, in which (B) the flame retardant is an The components were blended by means of a ribbon aromatic bromine compound. 4,966,935 78 3. A polybutylene terephthalate composition as claimed in claim 1, which comprises (B) 1 to 30 percent 5. A polybutylene terephthalate composition as claimed in claim 1, in which (C) the antimony trioxide has an average particle size of 5 to 7 microns. by weight, per polybutylene terephthalate, of the flame 6. A polybutylene terephthalate composition as retardant and (C) 1 to 15 percent by weight, based on 5 claimed in claim 1, which further comprises (D) 0.5 to 40 percent by weight of polycarbonate. polybutylene terephthalate, of the antimony trioxide. 7. A polybutylene terephthalate composition as 4. A polybutylene terephthalate composition as claimed in claim 1, which further comprises (E) 1 to 60 percent by weight of a reinforcing filler selected from claimed in claim 1, in which (C) the antimony trioxide 10 the group consisting of glass flake, glass fiber and mica. has an average particle size of 2 microns or larger. ***** 15 20 25 30 35 40 45 50 55 60 65