JPS6228176B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an aromatic polyester resin composition having excellent thermal stability, particularly stability against hot water. Aromatic polyester (hereinafter referred to as APC) obtained from aromatic dicarboxylic acids or their ester-forming derivatives and bisphenols or their ester-forming derivatives has a high heat distortion temperature and excellent mechanical and electrical properties. It is a transparent resin that has many properties, and its usefulness is widely known, but
One of the drawbacks of APC is that if it is left in liquids such as hot water or steam for a long time, crazes or microcracks occur in the molded product, resulting in turbidity and a decrease in strength. For this reason APC
The development of applications for these products has been restricted in the field of tableware and medical containers, which are repeatedly sterilized and sterilized with hot water or steam, and there is a strong demand from the consumer side for improvements in these properties. As a method for improving this property, there is a method of blending polyethylene terephthalate with APC (Japanese Patent Application Laid-open No.
50-15834), a method of blending polybutylene terephthalate (see JP-A-50-23447), a method of blending trialkyl phosphite or triaryl phosphite (JP-A-49-1988), 61244) have been proposed. However, although the above method is effective to some extent in preventing the occurrence of crazes or microcracks in hot water or steam, it is not effective in maintaining impact strength, and the thermal stability during processing is extremely low. Unfortunately, the molecular weight is significantly reduced and the physical properties are significantly deteriorated, making it extremely unsatisfactory for practical use. There has been a strong demand for a method that prevents the occurrence of crazes or microcracks in hot water or steam, and suppresses a decrease in impact strength. In view of the above-mentioned circumstances, the inventors of the present invention continued their intensive research and found that the above object could be achieved only when APC was blended with a specific amount of a copolymer having a specific structure. That is, in the present invention, 100 parts by weight of an aromatic polyester obtained from an aromatic dicarboxylic acid or an ester-forming derivative thereof and a bisphenol or an ester-forming derivative thereof, (a) the general formula (In the formula, R ₁ is H or CH ₃ , and R ₂ is an alkyl group having 1 to 14 carbon atoms.) 30% by weight or more of the monomer represented by (b) General formula (In the formula, R ₁ is H or CH _3. ) 3 to 40% by weight of a monomer represented by (c) general formula (In the formula, R ₁ and R ₃ are H or CH _3. ) Styrenic monomer represented by the general formula (In the formula, R ₁ is H or CH ₃ , and R ₄ is a hydroxyalkyl group having 2 to 3 carbon atoms.) This is a stabilized aromatic polyester resin composition containing 0.1 to 10 parts by weight of a copolymer obtained by copolymerizing a monomer mixture containing 67% by weight or less. The copolymer used in the present invention has the following formula: (a) General formula (In the formula, R ₁ is H or CH ₃ , and R ₂ is an alkyl group having 1 to 14 carbon atoms.) 30% by weight or more of a monomer represented by (b) general formula (In the formula, R ₁ is H or CH _3. ) 3 to 40% by weight of a monomer represented by (c) general formula (In the formula, R ₁ and R ₃ are H or CH _3. ) Styrenic monomer represented by the general formula (In the formula, R ₁ is H or CH ₃ , and R ₄ is a hydroxyalkyl group having 2 to 3 carbon atoms.) It is a copolymer obtained by copolymerizing a monomer mixture containing 67% by weight or less of monomer. Examples of monomers having the structure (a) include methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, Isobutyl methacrylate, methacrylic acid 2-
Ethylhexyl, lauryl methacrylate, tridecyl methacrylate, etc. are commonly used. If the amount of these monomers used is less than 30% by weight of the total monomers,
Since the compatibility with APC is not sufficient, it does not exhibit a sufficient effect in improving the hot water resistance of APC, which is a feature of the present invention. If the amount of the monomer having the structure (b) is less than 3% by weight of the total monomers, the reaction with APC will not occur sufficiently, so the effect of improving hot water resistance will not be increased, and
If it exceeds 40% by weight, the reaction will be excessive and the smoothness and impact strength of the APC molded product will be impaired. Examples of monomers having the structure (c) include β-
Hydroxyethyl acrylate, β-hydroxypropyl methacrylate, styrene, α-methylstyrene, vinyltoluene, etc. can be mentioned, and for the purpose of imparting appropriate melt viscosity to the copolymer, it is 67% by weight or less, preferably 5 to 50% by weight. Copolymerize within a range of % by weight. The secondary transition point of the copolymer containing (a), (b) and (c) is preferably 5°C to 60°C in order to provide APC with an appropriate melting viscosity. The secondary transition point is a value measured by determining the inflection point of temperature change in specific volume using the dilatometric method. In addition, the average molecular weight is
For the purpose of appropriately dispersing and dissolving APC, it is preferably 1,500 to 30,000. The appropriate amount of the copolymer to be added to APC is 0.1 to 10 parts by weight per 100 parts by weight of APC. If it is less than 0.1 part by weight, the reaction with APC will be insufficient and the effect of improving hot water resistance will not be sufficient, and if it exceeds 10 parts by weight, the reaction will be excessive and the surface of the molded product will become rough, and the impact strength and softening point will decrease. A blending amount of 0.3 to 5 parts by weight is more preferable. The actual amount to be blended is selected depending on the structure of the copolymer and the balance between the improvement effect obtained and the properties deteriorated. The APC used in the present invention is an aromatic polyester obtained from an aromatic dicarboxylic acid or an ester-forming derivative thereof and a bisphenol or an ester-forming derivative thereof. Specific examples of aromatic dicarboxylic acids used in the present invention include terephthalic acid, isophthalic acid, naphthalene dicarboxylic acid, and nuclear alkyl-substituted and nuclear halogenated derivatives thereof. Further, examples of ester-forming derivatives of aromatic dicarboxylic acids include acid chlorides, phenyl esters, alkyl esters, and the like of these aromatic dicarboxylic acids. Preferred are terephthalic acid, isophthalic acid and ester-forming derivatives thereof. More preferably,
It is a mixture of terephthalic acid and isophthalic acid or a mixture of their ester-forming derivatives. The bisphenols used in the present invention are represented by the following general formula. In the above formula, Ar ¹ represents an aromatic nucleus such as a phenylene nucleus, a biphenylene nucleus or a naphthylene nucleus, and R represents a hydrogen atom, an alkyl group (such as a methyl group and an ethyl group), a halogenated alkyl group, an aryl group (such as a phenyl group and (naphthyl group), halogenated aryl group, aralkyl group (e.g. benzyl group and phenylethyl group), halogenated aralkyl group, alkyl-substituted aryl group, halogenated alkyl-substituted aryl group, alicyclic group or halogenated alicyclic group, is an alkylene group or alkylidene group such as methylene group, ethylene group, propylene group, ethylidene group, propylidene group and isopropylidene group, aromatic group, tertiary amino group (-N
(alk)-), ether group (-O-), carbonyl group (-CO-) or sulfur-containing group, such as sulfide (-S-), sulfoxide (-SO-) or sulfonyl (-SO ₂ -) Indicates two or more alkylene or alkylidene groups interconnected by a group. X may also be an alicyclic group or a sulfur-containing group, such as a sulfide, sulfoxide or sulfonyl group, an ether group, a carbonyl group or a tertiary amino group. Y is a halogen atom, a nitro group, or a group represented by R' or OR'(R' has the same meaning as R described above), m is from 0 to the number of substitutable hydrogen atoms on X n is an integer from 0 to the number of substitutable hydrogen atoms on aromatic Ar ¹ , p is at least 1
, q is an integer from 0 to 1, and r is an integer (however, when q is 0, r may be 0). When there is one or more substituents Y in the bisphenol shown in the above formula, these substituents may be the same or different. The same is true for R and R'. The substituent Y and the hydroxyl group on the aromatic nucleus may be in the ortho-, meta- or para-position. Moreover, you may use these mixtures. Examples of bisphenols represented by the above general formula and suitable for carrying out the method of the present invention are as follows. Bis(4-hydroxyphenyl)-methane, bis(4-hydroxy-3-methylphenyl)-methane, bis(4-hydroxy-3,5-
dichlorophenyl)-methane, bis(4-hydroxy-3,5-dibromophenyl)-methane, bis(4-hydroxy-3,5-difluorophenyl)-methane, bis(4-hydroxyphenyl)-
Ketone, bis(4-hydroxyphenyl)-salafuide, bis(4-hydroxyphenyl)-sulfone, 4,4'-dihydroxydiphenyl ether, 1,1-bis(4-hydroxyphenyl)
-ethane, 2,2-bis(4-hydroxyphenyl)-propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl) enyl)−
Propane, 2,2-bis(4-hydroxy-3,
5-dibromophenyl)-propane, 2,2-bis(4-hydroxy-3-chlorophenyl)-propane, 2,2-bis(4-hydroxy-3,5
-dichlorophenyl)-propane, 2,2-bis(4-hydroxynaphthyl)propane, bis(4
-hydroxyphenyl)-phenylmethane, bis(4-hydroxyphenyl)-phenylmethane, bis(4-hydroxyphenyl)-4'-methylphenylmethane, 1,1-bis(4-hydroxyphenyl)2. 2,2-trichloroethane, bis(4
-hydroxyphenyl)-(4'-chlorophenyl)
-methane, 1,1-bis(4-hydroxyphenyl)-cyclohexane, bis(4-hydroxyphenyl)-cyclohexylmethane, 4,4'-dihydroxydiphenyl, 2,2'-dihydroxydiphenyl, 2. Dihydroxynaphthalenes such as 6-dihydroxynaphthalene, hydroquinone, resorcinol, 2,6-dihydroxytoluene, 2.
6-dihydroxychlorobenzene, 3,6-dihydroxytoluene. Ester-forming derivatives of bisphenol include diesters such as diacetate and dibenzoate, and mixtures thereof may also be used. Preferred bisphenols are 2,2-bis(4-hydroxyphenyl)-propane and its nuclear halogen-substituted products and nuclear alkyl-substituted products. In addition, branched aromatic polyesters synthesized by adding a small amount of trihydric or higher alcohol or its ester-forming derivative as a branching agent,
APC with polyester such as polycarbonate, polyethylene terephthalate, and nylon 6,
It can also be applied to systems blended with thermoplastic resins such as polyamides such as nylon 66. The method of compounding the copolymer into APC is by solution blending or by homogeneous compounding in a two roll, Banbury mixer, extruder or other mixing machine known in the art. It may also contain commonly used additives such as ultraviolet absorbers, colorants, and lubricants. The present invention will be explained below with reference to Examples, but these are merely illustrative and can be modified as appropriate within the scope of the present invention. In the examples, the heat distortion temperature was measured at a load of 18.6 kg/cm ² in accordance with ASTM D569-59. Mechanical properties are
Shown as Izot impact strength (with V-notch) according to ASTM D256. Hot water resistance was indicated by the change in appearance (presence or absence of craze generation) and the change in Izot impact strength when the molded product was immersed in hot water at 80°C for 300 hours. Example 1 As a basic structure

In [Formula], p-substitution is 50 mol%, m-substitution is 50 mol%, and ηsp/c measured at 25°C at a concentration of 0.5% in chloroform is 0.65.
dl/g. ) Aromatic polyester (abbreviated as APC)
20% by weight of methyl methacrylate, 35% n-butyl acrylate, 25% styrene, 25% β-hydroxyethyl acrylate, 2% glycidyl methacrylate, 18% secondary transition point obtained by copolymerizing the following monomers:
A solid copolymer (abbreviated as GM-1) with a number average molecular weight of 7800 is mixed in a Henschel mixer in the proportions shown in Table 1, and the mixture is melt-kneaded in a vented extruder to devolatilize the volatile components and form granules. A composition was obtained. The obtained composition was injection molded, and its processability was evaluated and various physical properties were measured. The results are shown in Table 1. Example 2 APC used in Example 1 was copolymerized with the following monomers: 20% by weight of ethyl acrylate, 15% lauryl methacrylate, 50% styrene, and 15% glycidyl acrylate.
A solid copolymer (abbreviated as GM-2) having a number average molecular weight of 5500 was mixed in a Henschel mixer in the proportions shown in Table 1, and evaluated in the same manner as in Example 1. The results are shown in Table 1. Comparative Example 1 A similar experiment was conducted using APC used in Example 1 alone and a system containing 15 parts by weight of GM-1. The results are shown in Table 1. Comparative Example 2 A similar experiment was conducted using a system in which 15 parts by weight of GM-2 was mixed with the APC used in Example 1. The results are shown in Table 1.

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Claims (1)

[Scope of Claims] 1. To 100 parts by weight of an aromatic polyester obtained from an aromatic dicarboxylic acid or its ester-forming derivative and bisphenols or its ester-forming derivative, (a) the general formula (In the formula, R ₁ is H or CH ₃ , and R ₂ is an alkyl group having 1 to 14 carbon atoms.) 30% by weight or more of a monomer represented by (b) general formula (In the formula, R ₁ is H or CH _3. ) 3 to 40% by weight of a monomer represented by (c) general formula (In the formula, R ₁ and R ₃ are H or CH _3. ) Styrenic monomer represented by the general formula (In the formula, R ₁ is H or CH ₃ , and R ₄ is a hydroxyalkyl group having 2 to 3 carbon atoms.) 1. A stabilized aromatic polyester resin composition comprising 0.1 to 10 parts by weight of a copolymer obtained by copolymerizing a monomer mixture containing 67% by weight or less of a monomer.