JPS6324022B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a thermoplastic polyester composition that has excellent chemical resistance, particularly resistance to alcohol-mixed gasoline, and good moldability. Thermoplastic polyesters, represented by polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycyclohexane dimethylene terephthalate, etc., are used in mechanical parts, electrical parts, automobile parts, etc. due to their excellent properties. There is. On the other hand, due to the deterioration of the crude oil situation in recent years, there is a growing trend to use alcohol such as methanol and ethanol as an energy source, and in particular, research is being carried out around the world on the technology of using alcohol-mixed gasoline, in which alcohol is added to gasoline, as automobile fuel. has been done. However, although thermoplastic polyester has excellent properties, it has poor chemical resistance, especially resistance to alcohol-mixed gasoline, so when it is applied to applications that come into contact with alcohol-mixed gasoline, such as in automobiles, various properties may deteriorate. This tendency is particularly remarkable at high temperatures. Further, thermoplastic polyester has poor moldability due to its crystallinity, and there are problems with dimensional accuracy, surface appearance, warpage, etc. of molded products. Therefore, the present inventors have conducted intensive studies to improve the chemical resistance of thermoplastic polyester, typified by its resistance to alcohol-mixed gasoline, and to obtain a thermoplastic polyester with excellent chemical resistance and moldability. The inventors have discovered that the above object can be effectively achieved by incorporating a carbodiimide compound and a specific additive system into polyester, and have thus arrived at the present invention. That is, the present invention uses thermoplastic polyester 100
(A) 0.01 to 5 parts by weight of at least one carbodiimide compound, (B) 0.005 to 5 parts by weight of at least one selected from amides, esters, metal salts of higher fatty acids, polyalkylene waxes, and polyorganosiloxanes based on parts by weight. 5 parts by weight and (C) talc 0.01~
A thermoplastic polyester composition containing 5 parts by weight is provided. The thermoplastic polyester used in the present invention essentially contains at least one acid component selected from terephthalic acid, 2,6-naphthalene dicarboxylic acid, isophthalic acid, etc., and ethylene glycol, propylene glycol, butylene glycol, hexylene glycol. Alternatively, it can be obtained by polycondensation with at least one diol component selected from polyalkylene glycols such as polyethylene glycol and polytetramethylene glycol. Specifically, polyethylene terephthalate (PET), polypropylene terephthalate ( PPT), polybutylene terephthalate (PBT),
In addition to polyhexylene terephthalate (PHT), polyethylene naphthalate (PBN), polybutylene naphthalate (PBN), etc., polyethylene isophthalate/terephthalate (PET/I), polybutylene terephthalate/isophthalate (PBT/I), etc. Examples include copolymerized polyesters such as Of course, these polyesters also contain other third components within 30 mol%, such as sulfoisophthalic acid, adipic acid,
Sebacic acid, phthalic acid, etc. may be copolymerized. The carbodiimide compound (A) used in the present invention is a compound having a carbodiimide group (-N=C=N-) in the molecule, and specifically includes diisopropylcarbodiimide, dicyclohexylcarbodiimide, di-O-triylcarbodiimide. , diphenylcarbodiimide, dioctyldecylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, N-triyl-N'-cyclohexylcarbodiimide, N-triyl-N'-phenylcarbodiimide, di-P-nitrophenylcarbodiimide, Di-P-aminophenylcarbodiimide, di-P-hydroxyphenylcarbodiimide, di-P-tolylcarbodiimide, di-P-
Chlorphenylcarbodiimide, di-P-methoxyphenylcarbodiimide, di-3,4-dichlorophenylcarbodiimide, di-2,5-dichlorophenylcarbodiimide, di-O-chlorophenylcarbodiimide, P-phenylene-bis -di-O-triylcarbodiimide, P-phenylene-bis-dicyclohexylcarbodiimide, P-
Mono- or dicarbodiimide compounds such as phenylene-bis-di-P-chlorophenylcarbodiimide, hexamethylene-bis-dicyclohexylcarbodiimide, ethylene-bis-dicyclohexylcarbodiimide, ethylene-bis-diphenylcarbodiimide, and poly(4,4'- diphenylmethanecarbodiimide), poly(3,3'-dimethyl-
4,4'-diphenylmethanecarbodiimide), poly(tolylcarbodiimide), poly(p-phenylenecarbodiimide), poly(m-phenylenecarbodiimide), poly(3,3'-dimethyl-4,
4'-diphenylmethanecarbodiimide), poly(naphthylenecarbodiimide), poly(1,6-hexamethylenecarbodiimide), poly(4,4'-
methylenebiscyclohexylcarbodiimide),
Poly(1,3 and 1,4-cyclohexylenecarbodiimide), poly(1,3-diisopropylphenylenecarbodiimide), poly(1-methyl-
Examples include polycarbodiimide compounds such as 3,5-diisopropylphenylenecarbodiimide), poly(1,3,5-triethylphenylenecarbodiimide), and poly(triisopropylphenylenecarbodiimide), and two or more of these may be used in combination. You can also do it. Among these, dicyclohexylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, O-triylcarbodiimide, poly(4,4'-diphenylmethanecarbodiimide), poly(tolylcarbodiimide), poly(phenylenecarbodiimide), The use of poly(triisopropylphenylenecarbodiimide) is preferred. The amount of these carbodiimide compounds added is 0.01 to 5 parts by weight, preferably 0.05 to 2 parts by weight, per 100 parts by weight of the thermoplastic polyester. If it is more than 5 parts by weight, the composition will be colored and its commercial value will be reduced, and if it is less than 0.01 part by weight, the effect of improving the alcohol resistance of mixed gasoline cannot be obtained, which is not preferable. By incorporating the above-mentioned carbodiimide compound, the chemical resistance of thermoplastic polyester, typified by its resistance to alcohol-mixed gasoline, is dramatically improved, but on the other hand, there is a problem in that the moldability of the thermoplastic polyester itself is further deteriorated than originally. There is. Therefore, it is necessary for the composition of the present invention to further contain a shape-retardant agent and a nucleating agent. However, it is not possible to improve the moldability uniformly, and only when a specific additive system consisting of (B) and (C) is used, excellent alcohol resistance and moldability can be achieved. A thermoplastic polyester composition can be obtained. Compounds (B) used as mold release agents in the present invention include amides, esters, and metal salts of higher fatty acids such as lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, and montanic acid, and polyalkylene compounds such as polyethylene wax. It is at least one selected from polyorganic waxes and polyorganosiloxanes such as polydimethylsiloxane. Specific examples of higher fatty acid compounds include higher fatty acid amides such as ethylene bisstearamide, methylene bisstearamide, and ethylene bis-3(3,5-di-tert-butyl-4-hydroxyphenol)propanamide. , higher fatty acid esters (and partially saponified products thereof) such as butyl stearate, stearic acid monoglyceride, stearic acid sorbitan ester, montanic acid aliphatic dihydric alcohol ester, and sodium stearate, barium stearate, calcium stearate, magnesium stearate, Examples include fatty acid metal salts such as aluminum stearate, calcium palmitate, magnesium palmitate, calcium dodecanedicarboxylate, calcium montanate, and calcium sebacate. Among these compound group (B), it is particularly preferable to use ethylene bisstearamide, barium stearate, magnesium stearate, partially saponified calcium of montanic acid ester, and polyethylene wax having a molecular weight of 2,000 to 4,000. The amount of mold release agent selected from the above compound (B) group is 0.005 to 100 parts by weight of thermoplastic polyester.
The amount added is 5 parts by weight, preferably 0.01 to 2 parts by weight. If the amount added is less than 0.005 parts by weight, the improvement in mold releasability is insufficient, while if it exceeds 5 parts by weight, the mechanical properties of the thermoplastic polyester itself It is not preferred because the properties tend to be impaired. The compound (C) used as a nucleating agent in the present invention is talc. Other known nucleating agents include clay, wollastenite, mica, asbestos, kaolin, alumina, etc., but in the composition of the present invention, only when talc is used, the above compound (B) group and the like are used. They act synergistically to provide the effect of specifically improving the moldability of a particular composition comprising a thermoplastic polyester and a carbodiimide compound. The amount of talc added is 0.01 to 5 parts by weight, preferably 0.1 to 5 parts by weight, per 100 parts by weight of thermoplastic polyester.
If the amount added is 0.01 part by weight or less, the effect of improving moldability is small, and if it exceeds 5 parts by weight, the mechanical properties of the thermoplastic polyester itself tend to be impaired, so it is preferable. do not have. The composition of the present invention may contain conventional additives, such as antioxidants, ultraviolet absorbers, heat stabilizers, plasticizers, dyes, pigments, and granular and fibrous reinforcing agents, to the extent that the object of the present invention is not impaired. , a flame retardant, and the like. In addition, small amounts of other thermoplastic resins (e.g. polyethylene, polypropylene, acrylic resins, fluorine resins, polyamides, polyacetals, polycarbonates, polysulfones, polyphenylene oxides, etc.), thermosetting resins (e.g. phenolic resins,
melamine resin, polyester resin, silicone resin, epoxy resin, etc.), soft thermoplastic resin (for example, ethylene/vinyl acetate copolymer, polyester elastomer, ethylene/propylene terpolymer, etc.). The method for producing the composition of the present invention is not particularly limited, but preferably, the thermoplastic polyester, the carbodiimide compound, the compound (B), and the talc are uniformly mixed using an extruder at a temperature equal to or higher than the melting point of the thermoplastic polyester. Examples include a method of melt-kneading a mixture. The obtained composition can be molded by any commonly known method such as injection molding or extrusion molding. Molded articles obtained from the composition of the present invention have excellent chemical resistance and moldability, and can be used for various purposes such as electrical/electronic parts, automobile parts, and precision equipment parts such as watches. However, it is particularly useful for automotive parts applications that take advantage of its alcohol-resistant mixed gasoline properties. The present invention will be explained in detail below with reference to Examples. In addition, the amount added in the examples is parts by weight, and the relative viscosity is 0.5% orthochlorophenol solution at 25°C.
This is the value measured at Examples 1 to 4, Comparative Examples 1 to 6 Polybutylene terephthalate with a relative viscosity of 1.58
100 parts by weight were dry blended with various polycarbodiimide compounds shown in Table 1, a mold release agent (ethylene bisstearamide) and talc, and an extruder with a 40 mmφ screw set at 250°C was used. The mixture was melt mixed and pelletized.
Next, the obtained pellets are molded using a screw in-line type injection molding machine with a 10 oz injection capacity set at 250°C at a mold temperature of 80°C to transform a square plate with a thickness of 1mm and 100mm square. The minimum molding time required to release the mold from the mold without any problems was measured. Also, ASTM type V dumbbells were obtained by punching and pressing a square plate having a good appearance.
This test piece was placed in an autoclave filled with alcohol mixed gasoline (gasoline/ethanol = 85/15, volume ratio), and the temperature was adjusted to 80°C.
Test pieces were taken out at various times and subjected to a tensile test (ASTM D638) to determine the processing time at which the strength reached 50% of the initial tensile strength (strength retention rate 50%). The results are shown in Table 1.

[Table] As is clear from the results in Table 1, it is only by adding a polycarbodiimide compound, a mold release agent, and talc to polybutylene terephthalate that excellent alcohol resistance and good moldability can be achieved. It can be seen that a thermoplastic polyester composition having the following properties can be obtained. Examples 5 to 8, Comparative Examples 7 to 14 Polybutylene terephthalate with a relative viscosity of 1.42
Dicyclohexylcarbodiimide, various mold release agents shown in Table 2, and talc were dry blended to 100 parts by weight, and the mixture was melt mixed and pelletized using a 40 mmφ screw extruder set at 250°C. Next, the obtained pellets were molded in the same manner as in Example 1, and the minimum molding time was measured. In addition, an alcohol resistance mixed gasoline test was conducted in the same manner as in Example 1, and the number of days at which the strength retention rate reached 50% was determined. The results are shown in Table 2.

[Table] As is clear from the results in Table 2, adding a polycarbodiimide compound, a mold release agent, and a nucleating agent to polybutylene terephthalate results in excellent alcohol resistance and good mixed gasoline properties. It can be seen that a thermoplastic polyester composition having moldability is obtained.

Claims (1)

[Claims] 1 For 100 parts by weight of thermoplastic polyester, (A)
At least one carbodiimide compound 0.01-5
Part by weight, (B) At least one selected from amides, esters, metal salts of higher fatty acids, polyalkylene waxes, and polyorganosiloxanes, 0.005 to 5
A thermoplastic polyester composition containing parts by weight and (C) 0.01 to 5 parts by weight of talc.