JPH0452299B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermoplastic polyester composition that can provide a molded article with an excellent balance of impact resistance, high-temperature rigidity, and surface gloss. Thermoplastic polyesters, such as polybutylene terephthalate and polyethylene terephthalate, have excellent mechanical properties and heat resistance, and are widely used in applications such as automobile parts and other mechanical parts, as well as electrical and electronic equipment parts. The thermal deformation temperature, which indicates impact resistance and rigidity at high temperatures, is still insufficient, and various improvement measures are being considered. As a means to improve the impact resistance of thermoplastic polyester, it is common to blend fibrous reinforcing agents such as glass fibers and various elastic rubber polymers. Even if the impact resistance can be improved, there is a problem in that the reinforcing agent is prominently embossed on the surface of the molded product, resulting in a molded product with poor surface gloss and appearance. The applicant has searched for an optimal elastic rubber polymer to improve the impact resistance of thermoplastic polyester. It is effective to use a polymer and an ethylene copolymer consisting of ethylene and an α-olefin having 3 or more carbon atoms, either alone or in combination, or (2) to combine these copolymers with a fibrous reinforcing agent. I discovered something and suggested it first. However, the above method (1) has insufficient rigidity at high temperatures, and the above method (2) improves the stiffness at high temperatures, but the fibrous reinforcing agent stands out and only molded products with poor appearance can be obtained. The disadvantage is that it cannot be used. Therefore, the present inventors investigated with the aim of obtaining a thermoplastic polyester composition that can provide excellent molded products with a balance of impact resistance, rigidity at high temperatures, and surface gloss, and found that α-olefin, α, β - Thermoplastic polyester produced by using a specific amount of potassium titanate whiskers in combination with a glycidyl group-containing copolymer consisting of a glycidyl ester of an unsaturated acid and/or an ethylene copolymer consisting of ethylene and an α-olefin having 3 or more carbon atoms. The present invention was accomplished by discovering that the above object can be effectively achieved by blending with That is, the present invention uses (A) a glycidyl group-containing copolymer consisting of an α-olefin and a glycidyl ester of an α,β-unsaturated acid, and (B) a glycidyl group-containing copolymer consisting of ethylene and an α-olefin having 3 or more carbon atoms, based on 100 parts by weight of a thermoplastic polyester.
- Provides a thermoplastic polyester composition comprising 0.1 to 40 parts by weight of at least one selected from olefin ethylene copolymers and 1 to 70 parts by weight of potassium titanate whiskers. Although it is already known to use potassium titanate whiskers as a white coloring agent for thermoplastic polyester (Japanese Patent Publication No. 3499/1983), the effect of improving the mechanical properties of the composition is negligible.
However, the composition of the present invention in which potassium titanate whiskers are blended with the above-mentioned copolymers (A) and/or (B) into a thermoplastic polyester, shows that when the copolymer and potassium titanate whiskers are each added alone, In contrast, the synergistic effect of the two dramatically improves impact resistance, and it is possible to provide a molded product with excellent rigidity and surface appearance at high temperatures, typified by heat distortion temperatures. The thermoplastic polyester used in the present invention is dicarboxylic acid (or its ester-forming derivative)
It is a polymer or copolymer obtained by a condensation reaction mainly consisting of diol and diol (or its ester-forming derivative). Examples of dicarboxylic acids include terephthalic acid, isophthalic acid, orthophthalic acid, 2,6-naphthalene dicarboxylic acid, 1,5-naphthalene dicarboxylic acid, bis-benzoic acid, and bis(P-carboxyphenyl).
Aromatic dicarboxylic acids such as methane, anthracene dicarboxylic acid, and 4,4'-diphenyl ether dicarboxylic acid; aliphatic dicarboxylic acids such as adipic acid, sebacic acid, azelaic acid, and dodecanedioic acid; 1,3-cyclohexane dicarboxylic acid; 1,
Alicyclic dicarboxylic acids such as 4-cyclohexanedicarboxylic acid or their ester-forming derivatives may be used alone or in mixtures, and the diol component may include aliphatic glycols having 2 to 20 carbon atoms, such as ethylene glycol, propylene glycol, 1 , 4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,
6-hexanediol, decamethylene glycol, cyclohexanedimethanol, cyclohexanediol, etc., or long chain glycols with a molecular weight of 400 to 6000, such as polyethylene glycol, poly-1,3-propylene glycol, polytetramethylene glycol, etc., and mixtures thereof. can be mentioned. Specific thermoplastic polyesters include polyethylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, polypropylene terephthalate, polybutylene terephthalate,
Examples include polyhexamethylene terephthalate, polycyclohexane dimethylene terephthalate, and among these, particularly preferred are polybutylene terephthalate and polyethylene terephthalate, which have good mechanical properties. The α-olefin in the glycidyl group-containing copolymer (A) consisting of an α-olefin and a glycidyl ester of an α,β-unsaturated acid used in the present invention is ethylene, propylene, butene-1, etc., and ethylene is preferable. Can be used. Also,
Glycidyl esters of α,β-unsaturated acids have the general formula (In the formula, R is a hydrogen atom, a lower alkyl group, or a lower alkyl group substituted with a glycidyl ester group.) Specifically, glycidyl acrylate, glycidyl methacrylate, glycidyl ethacrylate, These include glycidyl itaconate, among which glycidyl methacrylate is preferably used. The amount of copolymerized glycidyl ester of α,β-unsaturated acid in the glycidyl group-containing copolymer is 1 to 10% by weight, particularly 3 to 9% by weight.
A range of weight percent is suitable. Furthermore, if it is 8% by weight or less, unsaturated monomers copolymerizable with the above copolymers, such as vinyl ethers, vinyl ester acids such as vinyl acetate and vinyl propionate, and acrylic acids such as methyl, ethyl, propyl, butyl, etc. Alternatively, one or more of methacrylic acid esters, acrylonitrile, styrene, carbon monoxide, etc. may be copolymerized. Preferred examples of the glycidyl group-containing copolymer (A) in the present invention include ethylene/glycidyl methacrylate copolymer, ethylene/vinyl acetate/glycidyl methacrylate copolymer, and ethylene/carbon monoxide/glycidyl methacrylate copolymer. Coalescence, ethylene/glycidyl acrylate copolymer, ethylene/
Examples include glycidyl acrylate/vinyl acetate copolymer. Next, α-olefins having 3 or more carbon atoms in the ethylene copolymer (B) consisting of ethylene and α-olefin having 3 or more carbon atoms used in the present invention are propylene, butene-1, pentene-1,3-
Examples include methylpentene-1 and octacene-1, and propylene and butene-1 are preferably used. The copolymerization ratio of ethylene and α-olefin having 3 or more carbon atoms is 40/60 to 99/1 (molar ratio), especially 70/
30 to 95/5 (molar ratio) is preferred. These copolymers (A) and (B) may be used alone or in combination, and the blending amount is 1 to 40 parts by weight, particularly 5 to 30 parts by weight, based on 100 parts by weight of thermoplastic polyester. Department. If the blending amount is less than 1 part by weight, the effect of improving impact resistance will not be sufficient, and 40
If the amount exceeds 1 part by weight, the moldability of the composition decreases, which is not preferable. In particular, when using the above copolymer (A),
If a compound that promotes the reaction between the epoxy compound and the carboxylic acid is further added to the composition of the present invention, the impact resistance can be further improved. These compounds include triphenylamine, tertiary amines such as 2,4,6-tris(dimethylaminomethyl)phenol, phosphorous esters such as triphenylphosphite and triisodecylphosphite,
Examples include phosphonium compounds such as triphenylallylphosphonium bromide, and tertiary phosphides such as triphenylphosphine. It refers to white needle-like crystals consisting of potassium titanate whiskers and single-crystalline fibers of potassium titanate used in the present invention. When this potassium titanate whisker is blended alone into a thermoplastic polyester, the heat distortion temperature is improved and a molded article with an excellent surface appearance can be obtained, but the reinforcing effect such as impact resistance is small. However, when this potassium titanate whisker and the above copolymer (A) and/or (B) are combined in a thermoplastic polyester, the effect of synergistically improving impact resistance and heat distortion temperature can be obtained. It will be done. The amount of potassium titanate whiskers is 1 to 70 parts by weight per 100 parts by weight of thermoplastic polyester.
In particular, 3 to 20 parts by weight is appropriate; if it is less than 1 part by weight, the effect of improving impact resistance is small, and if it exceeds 70 parts by weight, the bulk specific gravity of the potassium titanate whisker is small, so that the composition cannot be easily processed by an extruder. This is not preferable because the melt-kneading properties deteriorate. The composition of the present invention may contain reinforcing agents such as glass beads, talc, wollastenite, and glass fibers, lubricants such as stearate and silicone oil, potassium titanate whiskers, and thermoplastic polyester to the extent that the expression of the effect is not impaired. Known additives such as adhesives such as epoxies, dyes, pigments, plasticizers, UV absorbers, blowing agents and thickeners can be added to increase adhesion. The composition of the present invention can be produced by a generally known method, for example, by mixing the thermoplastic polyester, copolymer, potassium titanate whiskers, and other desired additives, feeding the mixture to an extruder or kneader, and melt-mixing the mixture. and a method of mechanically premixing and then directly mixing and molding using an injection molding machine. The composition of the present invention can be made into a molded product by extrusion molding, injection molding, compression molding, etc., and the molded product obtained has an excellent balance of impact resistance, rigidity at high temperatures, and surface appearance. , it can be expected to be applied to a variety of uses that take advantage of its characteristics. The effects of the present invention will be further explained below with reference to Examples. Example 1 For 100 parts by weight of polybutylene terephthalate (PBT1200L manufactured by Toray Industries, Inc.) with a melt viscosity of 6000 poise,
Ethylene/glycidyl methacrylate copolymer with copolymer composition shown in Table 1 and average fiber length
Potassium titanate whiskers with a fiber diameter of 15 μm and a fiber diameter of 0.3 μm were blended in the proportions shown in Table 1, and melt-mixed using an extruder.
Pelletized. Each pellet was placed in a 3-ounce screw in-line injection molding machine, and test pieces were prepared under conditions of a cylinder temperature of 250°C and a mold temperature of 70°C. Table 1 shows the results of evaluating the characteristics of each test piece obtained. The characteristics were evaluated in accordance with the following criteria. Tensile strength ASTM D638 Izot impact strength 〃 D256 Heat distortion temperature 〃 D648 Surface appearance Macroscopic observation ◎……Very good ○…Good ×…Poor Formability ◎…Very good fluidity ○… …Good ×…Poor molding

[Table] As is clear from the results in Table 1, the compositions of the present invention (Nos. 1 to 5) produce molded products with a balance of impact resistance, rigidity at high temperatures, surface appearance, and moldability. give. On the other hand, when blending only ethylene/glycidyl methacrylate copolymer (No. 7), the impact resistance and heat resistance are insufficient, and when blending only potassium titanate whiskers (No. 8), the effect of improving impact resistance is low. small. Also, if the blended amounts of ethylene/glycidyl methacrylate copolymer and potassium titanate whiskers exceed the respective specified amounts (No. 9, 10),
This makes molding difficult and makes it impossible to obtain a molded product with an excellent surface appearance. When glass fiber is added as a reinforcing agent (No. 11,
12) Although the mechanical properties are excellent, the glass fibers protrude on the surface of the molded product and the surface appearance is not good. Example 2 Compounds were pelletized using the same method as in Example 1 at the ratios shown in Table 2, and evaluated using the same method.
The results are shown in Table 2.

[Table] As is clear from the results in Table 2, the compositions of the present invention (Nos. 13 to 16) produce molded products with a balance of impact resistance, rigidity at high temperatures, surface appearance, and moldability. give. In particular, an example in which a glycidyl group-containing copolymer and an ethylene copolymer were combined (No. 15,
16) provides a molded product with particularly excellent impact strength. On the other hand, even when used in combination, if the total amount exceeds 40 parts by weight, moldability will deteriorate.

Claims (1)

[Claims] 1 For 100 parts by weight of thermoplastic polyester,
Selected from (A) a glycidyl group-containing copolymer consisting of an α-olefin and a glycidyl ester of an α,β-unsaturated acid, and (B) an ethylene-based copolymer consisting of ethylene and an α-olefin having 3 or more carbon atoms. A thermoplastic polyester composition comprising 0.1 to 40 parts by weight of at least one kind and 1 to 70 parts by weight of potassium titanate whiskers.