JPH0369943B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to polyester resin compositions. Specifically, the present invention relates to a polyester resin composition with improved hydrolysis resistance. Although polyester resin has excellent mechanical properties, it has the disadvantage that its mechanical properties deteriorate due to hydrolysis under high temperature and high humidity conditions. Conventionally, in order to suppress heat aging of polyester resin, compositions containing an ester represented by the above general formula [] in polyester resin (Japanese Patent Laid-Open No. 1983-1999) have been proposed.
210958) and compositions in which an epoxy compound is blended with polyester resin to improve the mechanical properties of polyester resin containing inorganic fillers (Tokuko Showa).
48-6175) is known. However, this composition also did not have sufficient hydrolysis resistance. As a result of extensive research into improving the hydrolysis resistance of polyester resins, the present inventors found that when using the ester represented by the above general formula [] together with an epoxy compound that does not contain halogen, The present invention was completed by discovering that the properties can be greatly improved. That is, the purpose of the present invention is to provide a polyester resin composition of great industrial value, and the gist of the present invention is to provide a polyester resin composition with the general formula ₂ −) _n COOCH ₂ ] _o C(CH ₂ OH) _4-o ... [] (In the formula, R is an alkyl group having 5 to 30 carbon atoms, and n is 1
The number ˜4, m indicates the number 1-3. ) Pentaerythritol ester
This is a polyester resin composition consisting of 0.01 to 5 parts by weight and 0.01 to 5 parts by weight of an epoxy compound that does not contain halogen. The present invention will be explained in detail below. The thermoplastic polyester used in the present invention is polyalkylene terephthalate obtained by the polycondensation reaction of terephthalic acid or its dialkyl ester with aliphatic glycols, or a copolymer mainly composed of this, and representative examples thereof as,
Examples include polyethylene terephthalate and polybutylene terephthalate. Examples of the aliphatic glycols mentioned above include ethylene glycol, propylene glycol, tetramethylene glycol, hexamethylene glycol, etc.; 30% by weight or less of cyclohexanediol, cyclohexanedimethanol, xylene glycol, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)propane,
-Hydroxy-3,5-dibromophenyl)propane, 2,2-bis(4-hydroxyethoxyphenyl)propane, 2,2-bis(4-hydroxyethoxy-3,5-dibromophenyl)propane, glycerin, pentaerythritol, etc. may be used in combination. In addition, together with terephthalic acid or its dialkyl ester, other dibasic acids, polybasic acids, or their alkyl esters, such as phthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphthalic acid, diphthalic acid, isophthalic acid, naphthalene dicarboxylic acid, diphthalic acid, etc. Enyldicarboxylic acid, adipic acid, sebacic acid, trimesic acid, trimellitic acid, alkyl esters thereof, and the like may be used in combination. General formula [RS(-CH ₂ -) _n COOCH ₂ ] _o C(CH ₂ OH) _4-o ...[] (In the formula, R is an alkyl group having 5 to 30 carbon atoms, and n is 1
The number ˜4, m indicates the number 1-3. ) In the ester of pentaerythritol represented by R, the alkyl group represented by R is a pentyl group, hexyl group, octyl group, 2-ethylhexyl group, nonyl group, decyl group, dodecyl group, tetradecyl group, hexadecyl group, octadecyl group. , eicosyl group, etc. If the number of carbon atoms in the alkyl group represented by R is too small,
When the polyester resin composition is molded, it tends to sublime, which inconveniently contaminates the molded product and the molding machine. Conversely, if the number of carbon atoms in the alkyl group is too large, the effect of preventing coloring due to heat will be reduced. Preferred alkyl groups have about 8 to 20 carbon atoms. Although n is a number from 1 to 4, a number from 3 to 4 is preferred, particularly a number from 4 because of the effect of preventing coloring due to heat. Further, n is preferably 2. Specific examples of pentaerythritol esters represented by the above general formula [] include pentaerythritol tetrakis (dodecylthiopropionate), pentaerythritol tetrakis (dodecylthioacetate), pentaerythritol tetrakis (dodecylthiobutyrate), and pentaerythritol tetrakis (dodecylthiobutyrate). Examples include tetrakis (octadecylthiopropionate), pentaerythritol tetrakis (2-ethylhexylthiopropionate), pentaerythritol tris (dodecylthiopropionate), pentaethritol bis(dodecylthiopropionate), etc. Pentaerythritol tetrakis (dodecylthiopropionate) is a trademark from Mitsubishi Yuka Co., Ltd.
It is also commercially available as Senox 412S, and is one of the preferred products. The content of the pentaerythritol ester represented by the above general formula [] is about 0.01 to 5 parts by weight, preferably about 0.05 to 2 parts by weight, based on 100 parts by weight of the thermoplastic polyester resin. If it is too small, no effect can be expected. On the other hand, if the amount is too high, it will adversely affect the physical properties of the molded product, such as a decrease in impact resistance and tensile elongation. Furthermore, during molding, pentaerythritol ester sublimes and adheres to the mold, causing other inconveniences. Epoxy compounds that do not contain halogens include allyl glycidyl ether, bisepoxy dicyclopentadienyl ether of ethylene glycol, epoxidized soybean oil, epoxidized linseed oil,
Aliphatic epoxy compounds such as butadiene diepoxide, octyl epoxytalate, epoxidized polybutadiene, aromatic epoxy compounds such as bisphenol A diglycidyl ether, tetraphenyl ethylene epoxide, diglycidyl ester of phthalic acid, 3,4 -Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3,4-epoxy-6
-methylcyclohexanecarboxylate, 2,
3-Epoxycyclohexylmethyl-3,4-epoxycyclohexanecarboxylate, 4-
(3,4-epoxy-5-methylcyclohexyl)
Butyl-3,4-epoxycyclohexanecarboxylate, 3,4-epoxycyclohexylethylene oxide, cyclohexylmethyl-3,
4-epoxycyclohexane carboxylate,
3,4-epoxy-6-methylcyclohexylmethyl-6-methylcyclohexanecarboxylate, vinylcyclohexene oxide, bis(3,
4-epoxycyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, 2-(3,4-epoxycyclohexyl-5,5-spiro-3,4
Examples include alicyclic epoxy compounds such as (epoxy) cyclohexane and metadioxane. The content of the epoxy compound is 0.01 to 5 parts by weight, preferably 0.02 to 2 parts by weight, per 100 parts by weight of the thermoplastic polyester resin. If it is too small, the expected effect will not be achieved. On the other hand, if the amount is too large, coloring will occur, which is not preferable. General formula shown above for thermoplastic polyester resin
In order to blend the ester of pentaerythritol and the epoxy compound represented by A well-known method such as preparing a master pellet containing a large amount of and mixing this with pellets for dilution can be employed. The polyester resin composition of the present invention includes reinforcing agents such as glass fiber and carbon fiber, fillers such as silica, alumina, silica alumina, silica magnesia, calcium carbonate, gypsum, and clays, halogen-containing aromatic compounds, Flame retardants such as halogen-containing acrylic resins or halogen-containing resins such as polycarbonate resins, flame retardant aids such as antimony trioxide, and other well-known additives may be included. The polyester resin composition of the present invention can be molded into various shapes such as three-dimensional molded products, sheets, tubes, and monofilaments by various molding methods such as injection molding, extrusion molding, compression molding, and blow molding. Because it has improved hydrolysis resistance, it is of great value as a material for electrical and electronic parts, automobile parts, and other industrial applications. EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to the following Examples unless the gist of the invention is exceeded. In addition, "parts" in the examples indicate "parts by weight." The tensile strength and tensile elongation rate are ASTM
According to D638 and bending strength is ASTM D790
Indicates the value measured according to. Example 1 and Comparative Examples 1 to 3 100 parts of polybutylene terephthalate with an intrinsic viscosity of 1.1 dl/g was added with an amount of pentaerythritol ester (pentaerythritol tetrakis (dodecylthiopropionate), Mitsubishi Yuka Co., Ltd., trademark: Senox 412S) and an epoxy compound (bisphenol A-diglycidyl ether, manufactured by Adeka Argus Chemical Co., Ltd., trademark: EP-17) were mixed and heated to 250°C using a 40 mm extruder.
The mixture was melt-kneaded and extruded into pellets. This pellet was molded using a 39-ounce injection molding machine (manufactured by Japan Steel Works, Model N-100B) and a test piece mold specified by ASTM, at a resin temperature of 258°C, a mold temperature of 80°C, and an injection time of 10°C. Injection molding was performed with a cooling time of 20 seconds. The obtained molded product was heated at 90℃ using a programmable broadband temperature and humidity tank (manufactured by Chino Chemical Electric Industry Co., Ltd.).
A hydrolysis test was conducted under conditions of RH 100%, and the tensile strength, tensile elongation, and bending strength of the molded product immediately after molding and after the 500-hour test were measured. The results were as shown in Table 1 below. For comparison, the results are also shown for the case where only the polyester resin was added (Comparative Example 1), the case where only the epoxy compound was added (Comparative Example 3), and the case where only the ester of pentaerythritol was added (Comparative Example 2).

[Table] Examples 2 to 4 and Comparative Examples 4 to 6 100 parts of the same polybutylene terephthalate used in Example 1, 15 parts of glass fiber, and the following
The pentaerythritol ester and epoxy compound shown in the table were mixed and molded in the same manner as in Example 1, followed by a hydrolysis test. The results were as shown in Table 2 below. For comparison, the results for the case where only pentaerythritol ester was added (Comparative Example 4), the case where only epoxy compound was added (Comparative Example 5), and the case where only glass fiber-containing polyester resin was added (Comparative Example 6) are also shown.

【table】

Claims (1)

[Claims] 1. For 100 parts by weight of thermoplastic polyester resin,
General formula [RS(-CH ₂ -) _n COOCH ₂ ] _o C(CH ₂ OH) _4-o ... [] (In the formula, R is an alkyl group having 5 to 30 carbon atoms, and n is 1
The number ˜4, m indicates the number 1-3. 0.01 to 5 parts by weight of pentaerythritol ester represented by ) and a halogen-free epoxy compound
A polyester resin composition comprising 0.01 to 5 parts by weight.