Document V3vyJnqNGQnyQjk9mLnQX6GwN

United States Patent [19] Morikawa et al. [U] 4,070,332 [45] Jan. 24,1978 [54] FLAME RETARDANT, NON-DRIPPING, SHAPE-RETAINING POLYESTER MOLDING COMPOSITION [75] Inventors: Masanobu Morikawa; Toshikazu Aoyama; Miyoji Yada, all of Nagoya, Japan [73] Assignee: Toray Industries, Inc., Tokyo, Japan [21] Appl. No.: 740,534 [22] Filed: Not. 10,1976 [30] Foreign Application Priority Data Nov. 18, 1975 Japan ..................................... 50-37758 [51] InL C1.2...........................C08K 3/22; C08K 5/03 [52] U.S. Q............................ 260/40 R; 260/45.75 R; 260/DIG. 24 [58] Field of Search............... 260/45.75 R, DIG. 24, 260/40 R [56] References Cited U.S. PATENT DOCUMENTS 3,676,362 3,751,396 3,824,209 3,833,685 3,869,420 7/1972 Yates...................... 260/45.75 R X 8/1973 Gall.................................... 260/40R 7/1974 Anderson.......................... 260/45.9R 9/1974 Wambach.................. 260/DIG. 24 3/1975 Mathis et al...................... 260/45.75R Primary Examiner--Sandra M. Person Attorney, Agent, or Firm--Miller & Prestia [57] ABSTRACT A flame retardant, non-dripping, shape-retaining ther moplastic polyester resin is disclosed comprising (a) a linear polyester, (b) a halogenated aromatic compound, (c) a zirconium compound, preferably in combination with antimony trioxide, and (d) a fibrous reinforcing agent. 12 Claims, No Drawings / 4,070,332 12 Thermoplastic polyester molding resins of the pres FLAME RETARDANT, NON-DRIPPING, ent invention are prepared by blending about 5-25 SHAPE-RETAINING POLYESTER MOLDING parts by weight of a halogenated aromatic compound COMPOSITION and about 1 - 20 parts by weight and preferably about 3 BRIEF SUMMARY OF THE INVENTION 5 - 15 parts by weight of a zirconium compound with about 100 parts by weight of a high molecular weight The present invention relates to a moldable thermo linear polyester, preferably in combination with anti plastic polyester resin having flame-retardant, non-drip mony trioxide, to improve the flame-retarding proper ping and shape-retention properties, which may be ties of the polyester resin, and preferably with the addi molded by conventional molding methods such as ex 10 tion of reinforcing fibers such as glass fibers or asbestos trusion molding, injection molding and press molding. to enhance the non-dripping properties of the product Thermoplastic polyesters, such as polyethylene tere- during burning. The linear aromatic polyester in accor phthalate and polybutylene terephthalate, are highly dance with this invention comprises at least one dicar- desirable for use as engineering plastics and as raw boxylic acid component selected from the group con materials for mechanical parts for various machines, 15 sisting of terephthalic acid; 2,6-naphthalene dicarbox- electrical equipment and parts for automobiles, for ex ylic acid; and l,2-bis(4~carboxyphenoxy)ethane, and at ample. Because of their excellent heat-resistance and least one diol component containing an aliphatic diol their high durability under thermal degradation, these having 2 to 6 carbon atoms. Examples of thermoplastic synthetic resins are highly suitable for such uses. How polyesters utilized in the present invention are polyeth ever, if these polyesters could be provided with effec 20 ylene terephthalate, polyhexamethylene terephthalate, tive flame-proofing properties, the practical usage of polyethylene-2, 6-naphthalate; polybutylene-2, 6-naph- such thermoplastic polyester resins would be greatly thalate; polyhexamethylene-2, 6-naphthalate; poly-1, extended. 4-cyclohexylene dimethylene terephthalate; poly-1, In applying a flame-retarding agent to a base polyes 4-cyclohexylene dimethylene terephthalate/isophtha- ter polymer, the original physical properties (such as 25 late copolymer; and copolyesters derived from biphenol shape retention) of the base polymer generally deterio A, terephthalic acid or isophalic acid, polyethylene rate, thus interfering with the desirability and use of the benzoate or polyethylene-bis (a-/?-phenoxy) ethane-4, polymer. Also, the resulting flame-retardant polyester 4'-carboxylate. Among these, polyethylene terephthal resin usually has a tendency to drip while burning, and ate and polybutylene terephthalate are preferred. this is difficult to prevent even with fibrous reinforce 30 The above polyesters may be modified for purposes ment. of this invention by replacing a maximum of about 30 Shape retention of a molded article during burning is mol% of the main dicarboxylic acid or diol components necessary, particularly when used, for example, to en with other copolymerizable dicarboxylic acids or diols close a high energy system such as the high voltage respectively, and a blend containing more than about section of a television receiver in order to prevent any 35 70% by weight of these polyesters and not more than spread of fire. Reduction of dripping is needed to pre about 30% by weight of other organic polyesters may vent the ignition of other molded articles by the flaming be used in accordance with the present invention. particles within the molded article. The incorporation into the polyester of a halogenated Several methods have been proposed with reference aromatic compound together with a zirconium com to glass reinforced polyester resins. For example, in 40 pound as a flame retarding agent is essential in the prac U.S. Pat. No. 3,833,535 the use of fumed colloidal silica tice of the present invention, with the aromatic com is disclosed. In U.S. Pat. No. 3,833,396, a blend of sup pound being selected from the following groups: plementary reinforcing agent such as asbestos fiber or whiskers is disclosed. These methods, however, are limited to the concept of preventing dripping of the 45 flaming particles. In these methods, the structural integ rity of the burning articles is not satisfactorily enhanced and the fine fibers and powder are difficult to handle in production. (X),, (X),, Accoringly, it is an object of the present invention to provide a non-dripping, flame-retardant thermoplastic polyester resin for use in molding, which resin has ex cellent shape retention properties during burning, and which resin may be safely and easily handled during the production process. Other objects and advantages of the present invention will become more readily apparent from the following 50 55 wherein R represents oxygen, sulfur dioxide, carbon dioxide, methylene, or phosphonates; X represents hy drogen, chlorine, or bromine with at least one chlorine or bromine; and n is 1 - 5 For example, hexabromobiphenyl ether, hexabromobiphenylsulfone, or decarbromobiphenyl ether and the like may be used, detailed description and examples, which are intended to be illustrative and are not intended to limit the scope of the invention as defined in the appended claims. 60 DETAILED DESCRIPTION OF THE INVENTION P0,, (X), The term "zirconium compound" as used herein is defined as a mixture or compound containing zirconium 65 wherein X represents hydrogen, chlorine, or bromine oxide components, a typical example of which is zirco with at least one chlorine or bromine; and n is 1 - 5 nium dioxide. The content of the zirconium dioxide in For example, hexachlorobiphenyl, hexabromobiphe the zirconium oxides is about 60 to 100% by weight. nyl, or decarbromobiphenyl may be used. 4 Antimony trioxide may be used independently in com bination with the zirconium compound or they may be simply mixed in the form of a mixed powder; however, a solid-solution of zirconium oxide with antimony oxide 5 commercially available as "Fire DTC" or "Fire DTA" (X),, (X), (trade name of Daiichi Kigenso Co., Japan) powder comprising about 40-80% by weight zirconium oxide wherein R represents hydrogen, acetate, or alkyl; X represents hyrogen, chlorine, or bromine with at least one chlorine or bromine; and n is I - 5 For example, 2,2-bis(3,5-dibromo 4-hydroxyphenol)propane, 2,2-bis(3,5-dichloro 4-hydroxyphenyl)propane, 2,2-bis(3,5-dibromo 4-acetoxyphenyl)propane may be used. An oligomer obtained from the reaction of epi- chlorohydorin, phosgene or diacidachloride with a compound from group III above, wherein at least one of R is hydrogene, may also be used in the present in vention. In the present invention a zirconium compound, pref erably a powdered zirconium dioxide is employed. Other zirconium compounds which contain a signifi cant zirconium oxide content may be used. These in clude calcined products obtained by calcination of zir conium hydroxide, ammonium zirconate, titanium zirconate, calcium zirconate, and/or zinc or other metallic zirconates. Such calcination products are deemed to be solid solutions of metal oxide (such as titanium dioxide, calcium oxide or zinc oxide, for example) mutually dissolved with zirconium dioxide mixtures of powders of the oxides may be substituted for such solid solutions, but in any event the percentage of zirconium dioxide should be about 60-100% by weight. The amount of the zirconium compound is about 1-20% by weight, preferably 3-15% by weight, based on the weight of the thermoplastic polyester. When the 15 20 25 30 35 and about 60-20% by weight antimony oxide is pre ferred. Referring to the matter of fibrous reinforcement, it has been found that improved non-dripping and shaperetaining properties are obtained when the fibrous rein forcement is present in an amount of about 5 to 70 parts, preferably 5 to 50 parts by weight per 100 parts by weight of thermoplastic polyester. The fibrous reinforc ing agent may be selected from the group consisting of glass fibers, asbestos, fibers, and gypsum fibers, silicate fibers and whiskers. Glass fibers and asbestos fibers are preferred. The combination of these is effective for improving the non-drip properties of the composition. Flame-retarding polyester resins of this invention may further contain coloring agents such as dyes or pigments, or both, crystallizing agents, fillers, reinforc ing agents, lubricants, plasticizers, heat-resistance agents, absorbers of ultraviolet rays, mold release agents, expanding agents, thickeners and coupling agents. Blending of a zirconium compound, a halogenated aromatic compound and antimony trioxide with a thermoplastic polyester may be carried out by conventional methods at any time before molding. The following examples are further illustrative of the present invention. As stated, the present invention is not intended to be limited to any of the specific features described in the examples, or other than as set forth in the appended claimed. amount of zirconium compound is less, the composition EXAMPLE 1 does not adequately control the dripping of the flaming particles during burning. On the other hand, when the amount of zirconium compound is above the indicated upper limit, the mechanical properties of the composi tion have been found to deteriorate. For use in the present invention, antimony trioxide is preferably used as an auxiliary flame retarding agent in combination with the aforementioned zirconium com pound. The antimony compound is preferably provided in an amount of about 1 - 20 parts by weight per 100 parts polyester by weight. To give sufficient flame retardance to the thermoplastic polyester composition, the use of more than about 1 part by weight of antimony trioxide is preferable. The use of more than the indi cated upper limit of antimony trioxide results in deterio 40 45 50 Polybutylene terephthalate (PBT) having an intrinsic viscosity of 1.26(o-chlorophenol sol. at 25 C) was mixed in a ratio as shown in Table 1 with decabromobiphenyl ether (DBE), antimony trioxide, zirco nium oxide and 2 mm in length of chopped strand glass fiber. The blend was extruded at 250' C on a cylinder and nozzle, and at 40 C in a mold. The molded speci mens were tested for tensile properties and flammability according to ASTM specification D-638 and UL-94 methods, respectively. The results, summarized in Table 1, show that zirconium oxide when added to the flame-retardant composition of glass reinforced PBT, prevents dripping of flaming particles, and that excel lent mechanical properties are retained. ration of the mechanical properties of the composition. Run No. Composition (parts by weight) PBT Glass Fiber DBE Antimony trioxide Zirconium dioxide Flammability 1/16" 1/8" Mechanical Properties Tensile Strength (kg/cm2) Tensile Elongation i 100 40 12 5 3 V-0(ND) V-OCND) 1867 Table 1 2 100 40 14 3 8 V-OCND) V-0(ND) 1865 3 100 40 5 12 6 V-0(ND) V-0(ND) 1980 4 100 45 12 3 8 V-0{ND) V-0(ND) 2059 5 100 50 12 0 10 V-1(ND) V-0(ND) 2230 3.2 4.1 3.0 2.8 3.1 6* 100 40 12 5 0 V-O(D) V-0(D) 1780 3.2 4,070,332 56 Table 1-continued___________________________________ Run No. 1 2 3 4 5 6* _________ (%)_________________________ Wherein*: is comparison V*0(ND): Fulfillod rating V-O of UL Standards without any dripping V-0(ND): Fulfilled rating V-O of UL Standards with dripping EXAMPLE 2 Table 3. The dry blends were extruded into pellets in the same manner as Example 1. The pellets were One hundred parts of PBT having an intrinsic viscos- 10 molded into 8 cm X 8 cm X 2 mm test pieces and were ity of 1.30(o-chlorophenol sol. at 25* C) were blended subjected to the flaming test for flyback transformers, with 40 parts of glass fiber, 20 parts of tetrabromobis- described in Denki Seihin Torishimari Ho of Japan phenol A and 5 parts of an additive as shown in Table 2. (Law for Regulation of Electric Products), a testing Following the procedure of example 1, the molded method quite similar to the 94-5V rating test of UL specimens for UL-94 flammability tests were molded. 15 Standards. The results, shown in Table 3, demonstrate The results, as shown in Table 2, demonstrate that the that zirconium oxide has a surprisingly beneficial, coop addition of zirconium oxide to glass-reinforced flame- erative effect on shape retention of the molded articles retardant PBT is particularly effective to prevent the during burning in combination with fibrous reinforce dripping of flaming particles during burning. ment. Table 3 Run No. Composition (Parts by weight) Flammability PBT Glass Fiber Asbestos Fiber Polytetrafluor ethylene DBE Antimony oxide Zirconium dioxide Flaming (sec) Shape Retention 12 13 14 15* 16* 100 100 100 100 100 40 30 40 40 30 05005 00 5 00 14 14 14 14 14 44444 5 5 5 0 0. 101 ND ND ND 5 D 3 D 17* 100 40 0 5 14 4 0 3 D Wherein *: Compared example Flaming: avenge flaming time for one application of flame ND: No deformation of specimens was observed while burning D: Deformation or dripping out of specimens was observed while burning Table 2 EXAMPLE 4 Run No. 7* s 9* 10* 11* Additive none Zirconium dioxide Zinc oxide Talc Titanium oxide Wherein *: control example Flammability (1/16" thick sample) V-2 V-0(ND) V-0(D) V-2 V-2 The compositions described in Table 4 were meltblended and molded into test specimens for tensile prop erties and flammability in a manner similar to Example 1. The results, shown in Table 4, indicate zirconium 40 oxide to be surprisingly effective in preventing dripping of flaming particles. Table 4 Run No. 18 19 20 21 22 23 24* Composition (Parts by Weight) PBT Glass Fiber DBE Antimony oxide "Fire DTC-100"** "Fire DTC-200"** 100 100 100 100 100 100 100 40 40 40 40 0 00 12 12 12 12 14 14 12 3 0 0 2 0 42 0 10 0 5 0 0 0 0 0 8 0 8 40 Flammability 1/16" 1/8" V-0(ND) V-0(ND) V-0(ND) V-0(ND) V-0(D) V-0(D) V-0(ND) V-0(ND) V-0(ND) V-0(ND) V-0(ND) V-0(ND) V-2 V-2 Mechanical Property Tensile Strength 1750 1810 1805 1765 523 603 615 (kg/cm2) Tensile Elongation 3.0 2.8 3.2 3.3 8.9 23 10 ________________ (%)______________________________ Wherein "Flame Cut": Calcination product from soluble zirconate "Fire DTC-100*': A solid solution of zirconium oxide and antimony oxide (80 to 20) by weight "Fire DTC-200": A solid solution of zirconium oxide and antimony oxide (70 to 30) by weight : as control Trade name of Dai Ichi Kigenso Co. V-2: Fulfilled rating V-2 of UL Standards V-0(NO): Fulfilled rating V-O of UL Standards without any dripping V-0(D): Fulfilled rating of UL Standards with dripping EXAMPLE 3 EXAMPLE 5 One hundred parts of PBT having intrinsic viscosity 65 The same runs as in Example 1 were carried out of 1.32(o-chlorophenol) were mixed with 40 parts of except various halogenated aromatic compounds were glass fiber, 20 parts of DBE, 4 parts of antimony triox used instead of decabromobiphenyl ether. The composi ide and various amounts of additives, as described in tions were prepared as follows: