JPH10310669A - Heat-resistant resin composition and heat-resistant molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat-resistant resin compsn. that is excellent in optical properties (e.g. clarity), heat resistance, and moldability, and has low water absorption properties. SOLUTION: This compsn. comprises an arom. vinyl/maleimide copolymer (1) which is formed by at least copolymerizing arom vinyl monomer (A) and maleimide monomers, (B) and prepf. comprises 50-97 wt.% units derived from the monomer A, 3-50 wt.% units derived from the monomer B, and 0-20 wt.% units derived from another monomer (C) copolymerizable with the foregoing two monomers and an arom. vinyl polymer (2) obtd. by polymerizing a monomer component contg. 85 wt.% or higher monomer A, provided polymer (1) and polymer (2) are thermodynamically compatible with each other.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an aromatic vinyl-maleimide copolymer and an aromatic vinyl polymer, which are excellent in optical properties such as transparency, heat resistance, moldability and low water absorption. The present invention relates to a heat-resistant resin composition having excellent heat resistance and a heat-resistant molded article formed from the heat-resistant resin composition.

[0002]

2. Description of the Related Art Conventionally, aromatic vinyl resins represented by polystyrene (PS) resins are colorless and transparent and have excellent properties such as resistance to acids and alkalis. Above all, general-purpose polystyrene resin (GPPS) has excellent moldability and low water absorption, so that the molded product after molding has excellent dimensional accuracy. In addition, since it is colorless and its transparency is close to that of glass, GPP
Since S can obtain a molded article having an appearance close to that of glass and can be colored vividly, the appearance of the obtained molded article can be made beautiful. For this reason, GPPS is suitably used in many fields such as automobile parts, electric equipment parts, decorative resin plates, and miscellaneous goods.

The impact resistance of a polystyrene resin can be improved by compounding a rubber. Although the impact-resistant polystyrene resin (HIPS) thus obtained is inferior in transparency as compared with GPPS, the impact resistance can be improved with an increase in the rubber content. It is suitably used in a wide range of fields such as equipment parts.

[0004] However, the above-mentioned aromatic vinyl resins generally have low heat resistance, and thus have a problem of being restricted in use. Therefore, as a method for improving the heat resistance of an aromatic vinyl resin, for example, a method of copolymerizing α-methylstyrene, methyl methacrylate, and maleic anhydride (Japanese Patent Publication No. 45-3)
1953) or a method of copolymerizing an aromatic vinyl monomer and a maleimide monomer (JP-A-61-2).
No. 78509).

As another method for improving the heat resistance of a polystyrene resin, a method of polymer blending a polystyrene resin with another resin is known. For example, polystyrene and polyphenylene ether (PPE)
A polystyrene-based resin having improved heat resistance can be obtained by combining them with each other.

Further, the AS resin, which is a copolymer of styrene and acrylonitrile, maintains transparency, which is a characteristic of polystyrene resin, and has improved heat resistance and impact resistance.

[0007]

However, according to the methods described in the above publications, the heat resistance of the obtained polystyrene resin is improved to some extent, but it is still not sufficient, and the method is not suitable for high temperature. However, there is a problem in that the stability of the resin is insufficient, and the moldability is also reduced.

In the above-mentioned polymer blending method, although the heat resistance is improved, the resulting polystyrene resin is colored by PPE. For this reason, there is a problem that the polystyrene resin cannot be used in a field of application of a polystyrene resin that requires colorlessness and transparency, such as an optical application.

Further, the above AS resin is excellent in transparency and heat resistance, but has low moldability and, in addition, has a problem that the dimensional accuracy of the molded article is inferior due to a slight water absorption. .

The present invention has been made in view of the above-mentioned conventional problems, and an object of the present invention is to provide a heat-resistant resin composition which is excellent in optical properties such as transparency, heat resistance, moldability, and low water absorption. It is to provide things.

[0011]

In order to solve the above-mentioned problems, the heat-resistant resin composition of the present invention comprises at least an aromatic vinyl monomer (A) and a maleimide monomer (B). An aromatic vinyl-maleimide copolymer obtained by copolymerization and an aromatic vinyl-based polymer obtained by polymerizing a monomer mixture containing at least 85% by weight or more of the aromatic vinyl monomer (A) ( 2) is included.

According to the above construction, heat resistance and moldability can be improved while maintaining high optical properties such as transparency of the aromatic vinyl polymer, and a heat-resistant resin composition having low water absorption. Things can be provided.

In the above aromatic vinyl-maleimide copolymer (1), the composition of the aromatic vinyl monomer (A) is preferably 50% by weight to 97% by weight, and more preferably 65% by weight to 9% by weight.
7% by weight is more preferred. Further, the composition of the maleimide monomer (B) is preferably 3% by weight to 50% by weight, and more preferably 3% by weight to 35% by weight. In addition, it is copolymerizable with the above-mentioned two kinds of monomers (aromatic vinyl monomer (A) and maleimide monomer (B)).
0% by weight of another monomer (C) which is different from the type of monomer
More preferably, it is contained in a composition of about 20% by weight. Further, in the aromatic vinyl polymer (2), the composition of the aromatic vinyl monomer (A) is more preferably 90% by weight. In the present invention, the aromatic vinyl-maleimide copolymer (1) and the aromatic vinyl copolymer (2) are preferably thermodynamically compatible with each other. Further, the content of the maleimide unit in the entire composition is preferably 13% by weight or less. In addition, the turbidity of the heat-resistant molded article obtained by molding the heat-resistant resin composition is 1
It is preferably 0.0 or less.

In particular, when the maleimide monomer (B) is N-cyclohexylmaleimide, the aromatic vinyl-maleimide copolymer (1) and the aromatic vinyl polymer (2) are compatible with each other. Further, a heat-resistant resin composition having excellent transparency, low coloring property and heat resistance can be obtained. In this case, the aromatic vinyl monomer (A) is preferably styrene, and the maleimide monomer (B) is N-
By using cyclohexylmaleimide, it is possible to obtain a heat-resistant resin composition which is more excellent in optical properties such as transparency, heat resistance, moldability and low water absorption.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below. The heat-resistant resin composition of the present invention comprises an aromatic vinyl-maleimide copolymer (1) obtained by copolymerizing at least an aromatic vinyl monomer (A) and a maleimide monomer (B). Hereinafter, the copolymer (1)) and the aromatic vinyl monomer (A) are at least 85.
An aromatic vinyl-based polymer (2) (hereinafter, referred to as polymer (2)) obtained by polymerizing a monomer mixture containing not less than% by weight.

In the copolymer (1), the composition of the aromatic vinyl monomer (A) is from 50% by weight to 97% by weight, and the composition of the maleimide monomer (B) is 3% by weight. ~ 5
0% by weight, and can be copolymerized with the above two kinds of monomers (aromatic vinyl monomer (A) and maleimide monomer (B)). 0% to 20% by weight of another monomer (C) different from the monomer
Is preferably contained in the composition.

As the optical properties of the heat-resistant resin composition of the present invention, the total light transmittance of the obtained heat-resistant molded article is preferably at least 85.0%, more preferably at least 88.0%. The turbidity (Haze) of the heat-resistant molded article is preferably 10.0 or less, more preferably 5.0 or less, and particularly preferably 3.0 or less. Further, the yellowing degree (YI) of the heat-resistant molded article is preferably 10.0 or less, more preferably 5.0 or less, and particularly preferably 3.0 or less.

In order for the heat-resistant resin composition of the present invention to exhibit excellent optical properties such as high total light transmittance, low turbidity (Haze) and low yellowing degree (YI), the above-mentioned copolymer must be used. It is preferable that (1) and the polymer (2) be thermodynamically compatible with each other.

The heat-resistant resin composition of the present invention contains the above-mentioned aromatic vinyl-maleimide copolymer (1) and the aromatic vinyl polymer (2). The content of the maleimide unit in the total composition is 13
It is preferably at most 10% by weight, more preferably at most 10% by weight.

When the content of the maleimide unit is within the above range, the heat resistance and the fluidity of the heat-resistant resin composition are improved, and the aromatic vinyl-maleimide copolymer (1) and the aromatic vinyl-maleimide copolymer (1) are mixed. The molded article has excellent transparency while maintaining compatibility with the vinyl polymer (2). on the other hand,
The content of the maleimide unit is out of the above range (that is, the content of the maleimide unit exceeds 13% by weight).
This is not preferred because the fluidity of the heat-resistant resin composition is reduced and the transparency of the molded article is reduced.

The lower limit of the content of the maleimide unit is not particularly limited. However, if the content of the maleimide unit is 0% by weight, the heat-resistant resin composition may be an aromatic vinyl-maleimide copolymer. It does not contain the coalescence (1), which deviates from the structure of the heat-resistant resin composition of the present invention. Therefore, the maleimide unit must always be contained at least in the aromatic vinyl-maleimide copolymer (1).

In the present invention, the thermodynamic compatibility between the copolymer (1) and the polymer (2) can be confirmed by measuring the glass transition point (Tg). Specifically, the glass transition point measured by a differential scanning calorimeter is determined by copolymer (1) and polymer (2).
Is observed at only one point in a mixture of two types of copolymers obtained by mixing the compounds, whereby thermodynamic compatibility is confirmed.

In the present invention, the aromatic vinyl monomer (A) used as a raw material of the copolymer (1) and the polymer (2) includes, for example, styrene, α-methylstyrene and paramethylstyrene. , Vinyl toluene, chlorostyrene and the like. Among these aromatic vinyl monomers (A), it is easy to obtain, and the reactivity with the maleimide monomers (B) and the copolymer (1) and the polymer (2) Styrene is particularly preferred from the viewpoint of the compatibility of the styrene. One of the above-described aromatic vinyl monomers may be used alone, or two or more of them may be used as an appropriate mixture.

The maleimide monomer (B) used as a raw material of the copolymer (1) includes, for example, N-cyclohexylmaleimide, N-phenylmaleimide, N-methylmaleimide, N-ethylmaleimide, Examples thereof include N-isopropylmaleimide, Nt-butylmaleimide, N-tribromophenylmaleimide, N-laurylmaleimide, and N-benzylmaleimide.

Among the above-mentioned maleimide monomers (B), N-phenylmaleimide and N-cyclohexylmaleimide are preferred from the viewpoints of transparency, low coloring property and heat resistance of the resulting heat-resistant resin. Cyclohexylmaleimide is particularly preferred. By using N-cyclohexylmaleimide, the composition range in which the copolymer (1) and the polymer (2) are compatible with each other is widened, whereby the transparency and low colorability of the resulting heat-resistant resin composition are obtained. , Heat resistance is further improved.

When N-tribromophenylmaleimide is used as a maleimide monomer, flame resistance can be imparted to the resulting heat-resistant resin composition in addition to transparency and heat resistance. As the maleimide monomers exemplified above, only one kind may be used, or two or more kinds may be appropriately mixed and used.

Further, as a raw material of the copolymer (1), another monomer (C) optionally used, that is, the above two types of monomers (aromatic vinyl monomers (A )
And the other monomer (C) which is copolymerizable with the maleimide monomer (B)) and is different from the above two monomers, for example, methacrylic esters; unsaturated nitriles; Acrylic acid esters; olefins; dienes; vinyl ethers; vinyl esters; vinyl fluorides; allyl esters or methacrylic esters of saturated fatty acid monocarboxylic acids such as allyl propionate; Polyvalent arylates;
Glycidyl compounds; unsaturated carboxylic acids and the like are particularly preferred.

As the methacrylic acid ester, a methacrylic acid ester having any one of an alkyl group having 1 to 18 carbon atoms, a cyclohexyl group and a benzyl group is preferable. As the methacrylic acid ester,
Specifically, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, amyl methacrylate, isoamyl methacrylate, octyl methacrylate, methacrylic acid 2 -Ethylhexyl, decyl methacrylate, lauryl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, 2-phenoxyethyl methacrylate, 3-phenylpropyl methacrylate, 2-hydroxyethyl methacrylate, and the like. Of these, methyl methacrylate is particularly preferred. One of these methacrylates may be used alone, or two or more of them may be appropriately mixed and used.

Examples of the unsaturated nitriles include acrylonitrile, methacrylonitrile, ethacrylonitrile, phenylacrylonitrile and the like. As the acrylate, an acrylate having at least one selected from the group consisting of an alkyl group having 1 to 18 carbon atoms, a cyclohexyl group, and a benzyl group is preferable.

Examples of the unsaturated carboxylic acids include acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid, and half-ester compounds and anhydrides thereof. One of the compounds exemplified as the other monomer (C) may be used alone, or two or more of them may be appropriately mixed and used.

In the present invention, the total of the aromatic vinyl monomer (A), the maleimide monomer (B) and the other monomer (C), that is, the copolymer (1) The proportion of the aromatic vinyl monomer (A) in all the monomer components used as the raw material (hereinafter, referred to as all monomer components) is as follows:
It is preferably in the range of 50% by weight to 97% by weight, more preferably in the range of 65% by weight to 95% by weight, and more preferably in the range of 70% by weight.
95% by weight is particularly preferred. When the proportion of the aromatic vinyl monomer (A) is less than 50% by weight, the compatibility and moldability of the heat-resistant resin composition are reduced. On the other hand, when the proportion of the aromatic vinyl monomer (A) exceeds 97% by weight, the heat resistance of the obtained copolymer (1) and the heat-resistant resin composition becomes insufficient.

The proportion of the maleimide monomer (B) in the total monomer components is preferably in the range of 3% by weight to 50% by weight, and more preferably in the range of 5% by weight to 35% by weight. . When the proportion of the maleimide monomer (B) is less than 3% by weight, a sufficient effect of improving heat resistance cannot be obtained, which is not preferable. On the other hand, when the ratio of the maleimide monomer (B) exceeds 35% by weight, the mechanical strength and moldability of the obtained copolymer (1) are reduced, and the copolymer (1) and the polymer ( Compatibility with 2) is reduced. Therefore, a heat-resistant resin composition excellent in optical properties such as transparency, mechanical strength, and moldability cannot be obtained.

The proportion of the other monomer (C) in the total monomer components is not particularly limited as long as the properties required for the obtained heat-resistant resin composition are not impaired. Not something. That is, the composition range of the copolymer (1) used in the present invention is 50% by weight to 97% by weight of the aromatic vinyl monomer (A) and 3% by weight to 50% by weight of the maleimide monomer (B). % By weight, and other monomers (C)
It is preferably 0% by weight to 20% by weight, and 65% to 95% by weight of an aromatic vinyl monomer (A), 5% to 35% by weight of a maleimide monomer (B), and others. Is more preferably in the range of 0 to 20% by weight of the monomer (C), 70 to 95% by weight of the aromatic vinyl monomer (A), and 70% to 95% by weight of the maleimide monomer (B). 5% by weight or more
It is particularly preferred that it is in the range of 35% by weight, and 0% to 20% by weight of the other monomer (C). However, the total amount of the aromatic vinyl monomer (A), the maleimide monomer (B), and the other monomer (C) is always 1
It is set to be 00% by weight.

The proportion of the aromatic vinyl monomer (A) in the monomer mixture used as a raw material of the polymer (2) is not particularly limited as long as it is at least 85% by weight. However, it is preferably 90% by weight or more, and more preferably 99% by weight or more. If the proportion of the aromatic vinyl monomer (A) in the monomer mixture is less than 85% by weight, the compatibility and moldability of the obtained polymer (2) and the heat-resistant resin composition will be reduced. It is not preferable.

The monomer other than the aromatic vinyl monomer (A) optionally contained in the monomer mixture is not particularly limited. The same monomer as the monomer (C) can be used.

The method for producing the copolymer (1) and the polymer (2) is not particularly limited.
Methods such as bulk polymerization, solution polymerization, suspension polymerization, and emulsion polymerization can be used. However, when the suspension polymerization or the emulsion polymerization is used, if the copolymer (1) and the polymer (2) are melt-mixed, the compatibility of each heat-resistant resin composition may be lowered, which is not preferable.

Specific examples of the solvent used in the solution polymerization method include, but are not particularly limited to, organic solvents such as toluene, xylene, ethylbenzene, methyl isobutyl ketone, and methyl ethyl ketone. Furthermore, specific examples of the polymerization initiator used in the above polymerization reaction include cumene hydroperoxide, diisopropylbenzene hydroperoxide, di-t-butyl peroxide, lauroyl peroxide, benzoyl peroxide, and t Radical polymerization initiators such as organic peroxides such as -butylperoxyisopropyl carbonate; azo compounds such as 2,2-azobisisobutyronitrile. One type of these polymerization initiators may be used alone.
More than one type may be used in combination. The amount of the polymerization initiator to be used may be appropriately set according to the combination of the monomers used, the reaction conditions, and the like, and is not particularly limited.

The other production conditions for producing the copolymer (1) and the polymer (2), for example, the reaction temperature and the reaction time are appropriately set according to the type of the monomer used. What is necessary is just, and it does not specifically limit. In the above polymerization reaction, respectively, a chain transfer agent such as an alkyl mercaptan or α-methylstyrene dimer, a hindered amine-based or benzotriazole-based weather resistance stabilizer, a hindered phenol-based antioxidant, as necessary. Additives such as a molecular weight modifier, a plasticizer, a heat stabilizer, and a light stabilizer may be added.

The weight average molecular weight of the copolymer (1) is
It is preferable that it is in the range of 30,000 to 300,000. The weight average molecular weight of the copolymer (1) is 300,0
If it exceeds 00, the molding processability of the obtained heat-resistant resin composition may deteriorate, which is not preferred. On the other hand, when the weight average molecular weight of the copolymer (1) is less than 30,000, many disadvantages such as deterioration of heat resistance and mechanical properties of the obtained heat resistant resin composition are caused, which is preferable. Absent.

The weight average molecular weight of the copolymer (2) is not particularly limited, but may be 50,000 to 500,
It is preferably in the range of 000. Copolymer (1)
If the weight-average molecular weight is within this range, the balance between fluidity and mechanical properties of the resulting heat-resistant resin composition will be extremely excellent.

When solution polymerization is employed as the method for producing the copolymer (1), the method for removing the copolymer (1) from the reaction solution (polymerization liquid) is not particularly limited.
(I) The reaction solution is introduced into a so-called volatile separation / removal device such as a twin-screw extruder equipped with a vent, and the polymer is separated from unreacted monomers and a solvent by removing volatile components from the reaction solution. Method and (ii) a solvent (poor solvent) that does not dissolve the polymer (eg, the aromatic vinyl polymer)
Various methods can be adopted, such as a method in which the above-mentioned polymer is precipitated (precipitated) by adding a reaction solution to the resulting mixture, and the obtained precipitate, that is, the above-mentioned polymer is separated by filtration and dried. Among these methods, the method (i) is preferred because it is simple and industrially advantageous.

The heat-resistant resin composition according to the present invention can be easily obtained by mixing the copolymer (1) and the polymer (2).

The blending ratio (weight ratio) of the copolymer (1) and the polymer (2) in the heat-resistant resin composition is 1/9.
Preferred is a range from 9 to 99/1, from 5/95 to 9
A range up to 5/5 is more preferred.

According to the present invention, the heat-resistant resin composition is copolymerized with the copolymer (1) containing the aromatic vinyl monomer (A) and the maleimide monomer (B) in the above-mentioned ratio. By containing the compound (2), heat resistance and moldability can be improved while maintaining optical properties such as high transparency of an aromatic vinyl copolymer represented by a polystyrene resin, and Low water absorption can be realized.

In particular, by using N-cyclohexylmaleimide as the maleimide monomer (B), the copolymer (1) and the polymer (2) can be mixed with each other without using a compatibilizer. Can be dissolved,
Further, a heat-resistant resin composition having excellent transparency, low coloring property and heat resistance can be obtained. In this case, by setting the aromatic vinyl monomer (A) to styrene, a heat-resistant resin composition having more excellent moldability and low water absorption can be obtained.

In the present invention, the method of mixing the copolymer (1) and the polymer (2) is not particularly limited. For example, the copolymer (1) and the polymer (2) may be mixed with an omni mixer or the like. After pre-blending with a mixer, the obtained mixture can be easily obtained by extrusion kneading.
The kneader used for the above-mentioned extrusion kneading is not particularly limited. For example, extruders such as a single-screw extruder and a twin-screw extruder; various known kneaders such as a pressure kneader may be used. Can be.

The heat-resistant resin composition of the present invention may contain, if necessary, a hindered phenol-based, phosphorus-based, or sulfur-based antioxidant; a reinforcing material such as glass fiber; phenyl salicylate, 2 (2'- UV absorbers such as (hydroxy-5-methylphenyl) benzotriazole and 2-hydroxybenzophenone; flame retardants such as tris (dibromopropyl) phosphate, ethylene tetrabromide, antimony oxide and zinc borate; anionic, cationic and non-flammable Ionic,
It may contain an antistatic agent such as an amphoteric surfactant; and a coloring agent such as an inorganic pigment, an organic pigment and a dye.

The heat-resistant resin composition of the present invention may contain a rubbery polymer as a third component other than the above-mentioned copolymer (1) and polymer (2). For example,
As the polymer (2), impact-resistant polystyrene (HIPS) containing a polybutadiene rubber may be used. Further, the third component other than the copolymer (1) and the polymer (2) may include polyphenylene ether and the like.

As described above, the heat-resistant resin composition according to the present invention is excellent not only in optical properties such as transparency, heat resistance and moldability but also in low water absorption. For this reason, the heat-resistant resin composition of the present invention is excellent in dimensional accuracy in a heat-resistant molded article after molding, and is required to have optical properties such as high transparency and heat resistance, moldability, and physical properties such as low water absorption. It can be suitably used in various application fields. For example, the heat-resistant resin composition can be suitably used for materials such as automotive parts for optics and electric equipment parts, which require high dimensional accuracy, transparency, heat resistance and the like.

[0050]

EXAMPLES Examples of the present invention will be described below as examples and comparative examples. Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition,
In each of the following Examples and Comparative Examples, the description of “parts” indicates “parts by weight”, and the description of “%” indicates “% by weight”.

Example 1 A solution polymerization was carried out using 58 parts of styrene, 8 parts of N-cyclohexylmaleimide, 34 parts of toluene and 0.05 part of t-butyl peroxoisopropyl carbonate. The mixture was introduced into a twin-screw extruder to remove volatile components, thereby obtaining a copolymer (1-1) as an aromatic vinyl-maleimide copolymer (1). Further, as a result of measuring the polymerization average molecular weight (Mw), glass transition temperature (Tg) and copolymer composition of the copolymer (1-1) by the following measurement methods, Mw was 15
000, Tg was 123 ° C., and the copolymer composition was 15.6% for N-cyclohexylmaleimide units and 84.4% for styrene units.

Next, 25% of the copolymer (1-1) as the copolymer (1) and “Estyrene G-20” (trade name; manufactured by Nippon Steel Chemical Co., Ltd.) as the polymer (2) were used. After pre-blending with an omni mixer so that the composition is 75%,
The mixture was charged into a 30 mmφ single screw extruder set at a cylinder temperature of 220 ° C., extruded and kneaded, and the resulting strand was pelletized to obtain a heat-resistant resin composition (1) of the present invention.
Using this heat-resistant resin composition (1), the glass transition temperature (Tg), the melt flow rate (MFR), and the content of the maleimide unit in the entire composition of the heat-resistant resin composition were measured. ℃, MFR 8.7
g / 10 minutes, the content of maleimide units was 4.2%.

The heat-resistant resin composition (1) was molded using an injection molding machine controlled at a cylinder temperature of 240.degree. C. and a mold temperature of 60.degree. ). Each physical property of this test piece was evaluated by the following evaluation methods. The results are shown in Table 1.

[0054]

[Table 1]

Glass Transition Temperature (Tg) The glass transition temperature was measured using a differential scanning calorimeter (trade name: DSC-8203, manufactured by Rigaku Corporation) under a nitrogen gas atmosphere using α-alumina as a reference. It was calculated by the midpoint method from a DSC (Differential Scanning Calorimetry) curve measured at a heating rate of 10 ° C./min from normal temperature to 220 ° C.

Maleimide Unit Content in Copolymer Composition and Total Composition As a result of elemental analysis, the maleimide content was calculated from the obtained nitrogen content.

Weight average molecular weight (Mw) The weight average molecular weight (Mw) was determined by GPC (Gel Permeation C
The weight average molecular weight was calculated by standard chromatographic method for molecular weight measurement using a chromatographic method.

Deflection temperature under load (HDT) The HDT of the above test piece was determined according to JIS K7207.
It was measured under the condition of a load of 18.5 kgf / cm ² .

Melt flow rate (MFR) The MFR of the test piece was determined according to JIS K7210.
It was measured at 200 ° C. under a load of 5 kgf.

Optical Properties The total light transmittance and turbidity (Haze) of the above test pieces were determined by AS
The yellowing degree (YI) of the test piece was measured according to JIS K7103 according to TM D1003.

Water absorption The water absorption of the test piece was determined according to JIS K7209.
It was measured under the condition of 23 ° C./water.

Example 2 The above copolymer (1-1) was treated with 5
Pellets of the heat-resistant resin composition (2) of the present invention were obtained under the same operating conditions as in Example 1 except that 0% and "Estyrene G-20" were blended so as to have a composition of 50%. Using this heat-resistant resin composition (2) and measuring the Tg, MFR and the content of maleimide units in the entire composition in the same manner as in Example 1, the Tg was 110 ° C. and the MFR was 6.8 g. / 10 minutes, the content of maleimide units is 7.6%
Met.

The heat-resistant resin composition (2) was molded under the same operating conditions as in Example 1 to obtain a test piece similar to that of Example 1. Each physical property of this test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 3 An aromatic vinyl-maleimide copolymer was prepared under the same operating conditions as in Example 1 except that 54 parts of styrene, 13 parts of N-cyclohexylmaleimide and 33 parts of toluene were used. Pellets of the copolymer (1-2) as the polymer (1) were obtained. The polymerization average molecular weight (Mw), glass transition temperature (Tg), and copolymer composition of the copolymer (1-2) were measured by the same measurement methods as in Example 1, and as a result, Mw was 170,000. , Tg is 145 ° C., and the copolymer composition is as follows: N-cyclohexylmaleimide unit 25.8%, styrene unit 7
4.2%.

Next, the copolymer (1-2) was added in an amount of 25%,
Pellets of the heat-resistant resin composition (3) of the present invention were obtained under the same operating conditions as in Example 1 except that “Estyrene G-20” was blended so as to have a composition of 75%. Using the heat-resistant resin composition (3), Tg was obtained in the same manner as in Example 1.
When the MFR and the content of the maleimide unit in the entire composition were measured, the Tg was 108 ° C., and the MFR was 7.2.
g / 10 minutes, the content of the maleimide unit was 6.3%.

The heat-resistant resin composition (3) was molded under the same operating conditions as in Example 1 to obtain a test piece similar to that of Example 1. Each physical property of this test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 4 The above copolymer (1-2) was treated with 5
Pellets of the heat-resistant resin composition (4) of the present invention were obtained under the same operating conditions as in Example 1 except that 0% and “Estyrene G-20” were blended so as to have a composition of 50%. Using this heat-resistant resin composition (4), the Tg, MFR and the content of the maleimide unit in the entire composition were measured in the same manner as in Example 1, and the Tg was 117 ° C. and the MFR was 6.0.
g / 10 minutes, the content of maleimide units was 12.8%.

The heat-resistant resin composition (4) was molded under the same operating conditions as in Example 1 to obtain a test piece similar to that of Example 1. Each physical property of this test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 5 The procedure of Example 1 was repeated, except that the copolymer (1) was replaced with 8 parts of N-phenylmaleimide instead of 8 parts of N-cyclohexylmaleimide. Under the operating conditions, pellets of the copolymer (1-3) as the aromatic vinyl-maleimide copolymer (1) were obtained. As a result of measuring the polymerization average molecular weight (Mw), glass transition temperature (Tg), and copolymer composition of the copolymer (1-3) by the same measurement method as in Example 1,
Mw is 150,000, Tg is 135 ° C.,
The copolymer composition was N-phenylmaleimide unit 16.3.
%, And styrene unit was 83.7%.

Next, 50% of the above copolymer (1-3) was added.
Pellets of the heat-resistant resin composition (5) of the present invention were obtained under the same operating conditions as in Example 1 except that “Estyrene G-20” was blended so as to have a composition of 50%. Using the heat-resistant resin composition (5), Tg was obtained in the same manner as in Example 1.
When the MFR and the content of the maleimide unit in the whole composition were measured, the Tg was 106 ° C. and 133 ° C.
Is 4.8 g / 10 min, and the content of the maleimide unit is 8.3.
%Met.

The heat-resistant resin composition (5) was molded under the same operating conditions as in Example 1 to obtain a test piece similar to that of Example 1. Each physical property of this test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 6 An aromatic vinyl-maleimide copolymer was prepared under the same operating conditions as in Example 1 except that 44 parts of styrene, 15 parts of N-cyclohexylmaleimide and 41 parts of toluene were used. Pellets of the copolymer (1-4) as the polymer (1) were obtained. As a result of measuring the polymerization average molecular weight (Mw), glass transition temperature (Tg), and copolymer composition of the copolymer (1-4) by the same measurement method as in Example 1, the polymerization average molecular weight Mw was 19.
000, Tg was 155 ° C., and the copolymer composition was 33.0% of N-cyclohexylmaleimide units and 67.0% of styrene units.

Next, 10% of the above copolymer (1-4) was added.
Pellets of the heat-resistant resin composition (6) of the present invention were obtained under the same operating conditions as in Example 1 except that “Estyrene G-20” was blended so as to have a composition of 90%. Using the heat-resistant resin composition (6), Tg was obtained in the same manner as in Example 1.
When the MFR and the content of the maleimide unit in the entire composition were measured, Tg was 105 ° C., and MFR was 7.0.
g / 10 minutes, the content of the maleimide unit was 3.5%.

The heat-resistant resin composition (6) was molded under the same operating conditions as in Example 1 to obtain a test piece similar to that of Example 1. Each physical property of this test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 7 The above copolymer (1-4) was replaced with 5
Pellets of the heat-resistant resin composition (7) of the present invention were obtained under the same operating conditions as in Example 1 except that 0% and "Estyrene G-20" were blended so as to have a composition of 50%. Using this heat-resistant resin composition (7), the Tg, MFR, and the content of maleimide units in the entire composition were measured in the same manner as in Example 1.
At 0 ° C., the MFR was 5.8 g / 10 min, and the content of maleimide units was 16.1%.

The heat-resistant resin composition (7) was molded under the same operating conditions as in Example 1 to obtain a test piece similar to that of Example 1. Each physical property of this test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Example 8 An aromatic vinyl-maleimide copolymer was prepared under the same operating conditions as in Example 1 except that 25 parts of styrene, 23 parts of N-cyclohexylmaleimide and 52 parts of toluene were used. Pellets of the copolymer (1-5) were obtained as the polymer (1). As a result of measuring the polymerization average molecular weight (Mw), glass transition temperature (Tg), and copolymer composition of the copolymer (1-5) by the same measurement method as in Example 1, Mw was 250,000. , Tg is 196 ° C., and the copolymer composition is as follows: N-cyclohexylmaleimide unit 52.8%, styrene unit 4
7.2%.

Next, 50% of the above copolymer (1-5) was added.
Pellets of the heat-resistant resin composition (8) of the present invention were obtained under the same operating conditions as in Example 1 except that “Estyrene G-20” was blended so as to have a composition of 50%. Using the heat-resistant resin composition (8), Tg was obtained in the same manner as in Example 1.
When the MFR and the content of the maleimide unit in the whole composition were measured, Tg was 106 ° C. and 194 ° C.,
MFR was 2.5 g / 10 minutes, and the content of maleimide units was 25.8%.

The heat-resistant resin composition (8) was molded under the same operating conditions as in Example 1 to obtain a test piece similar to that of Example 1. Each physical property of this test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

Next, comparative examples for illustrating the features of the present invention will be described as Comparative Examples 1 and 2, as follows.

Comparative Example 1 As a comparative heat-resistant resin composition, pellets of the copolymer (1-1) obtained in Example 1 were subjected to Tg, MFR, The content of the maleimide unit in the composition was measured.
As a result, Tg was 123 ° C. and MFR was 3.0 g / 10
The content of the maleimide unit was 15.6%.

The copolymer (1-1) was molded under the same operating conditions as in Example 1 to obtain a test piece similar to that of Example 1. Each physical property of this test piece was evaluated in the same manner as in Example 1. Table 1 shows these results together.
It was shown to.

Comparative Example 2 "Estyrene G-20" was used as a comparative heat-resistant resin in the same manner as in Example 1
g and MFR were measured. As a result, Tg is 100
C., MFR was 9.5 g / 10 min.

Further, the above-mentioned “Estyrene G-20” was molded under the same operating conditions as in Example 1 to obtain a test piece similar to that of Example 1. Each physical property of this test piece was evaluated in the same manner as in Example 1. The results are shown in Table 1.

As shown in Table 1, Examples 1-4 and 6
No. 8 to No. 8 are disclosed in JP-A-61-278509.
As compared with the resin composition of Comparative Example 1 corresponding to the heat-resistant polystyrene-based resin described in Japanese Patent Laid-Open Publication No. H10-210, while maintaining optical properties and heat resistance such as transparency, and having improved moldability and low water absorption. Has become.

Further, as compared with the resin composition of Comparative Example 2 corresponding to the conventional polystyrene resin, the heat-resistant resin compositions of Examples 1 to 4 showed optical properties such as transparency of polystyrene resin and moldability. , While improving heat resistance.

Copolymer Composition of Copolymer (1) and Table 1
As is clear from the results of Examples 1 to 4 and 6 to 8 shown in the above, the content of the maleimide monomer in each monomer component for obtaining the copolymer (1) is 35% or less. Is preferable.

Further, as is apparent from the comparison between the results of Example 5 and Comparative Examples, when N-phenylmaleimide was used as the maleimide monomer, the Tg was 10%.
Since two values of 6 ° C. and 133 ° C. are observed, no sufficient compatibility is observed between the copolymer (1) and the polymer (2), but a significant decrease in optical properties and moldability. Is avoided,
And it turns out that heat resistance has improved.

Further, as is apparent from the comparison between the results of Examples 1 to 6 and the results of Comparative Examples, the content of the maleimide unit in the entire composition of the heat-resistant resin composition is preferably 13% or less. .

In particular, as is apparent from the results of Examples 7 and 8, the content of the maleimide unit in the total composition was 13%.
%, Two values are observed as Tg (108 ° C. and 160 ° C. in Example 7, and 106 ° C. in Example 8).
And 194 ° C.), there is no sufficient compatibility between the copolymer (1) and the polymer (2). Therefore, it is found that the content of the maleimide unit is preferably 13% or less, but if other conditions are within a predetermined range,
It can be seen that a significant decrease in optical properties and moldability is avoided and the heat resistance is improved.

In addition, the heat-resistant resin composition of each Example was
As is evident from the results of the water absorption test, it has lower water absorption than the AS resin and the like, and the resulting heat-resistant molded article has excellent dimensional accuracy.

[0092]

As described above, the heat-resistant resin composition according to claim 1 of the present invention is obtained by copolymerizing at least the aromatic vinyl monomer (A) and the maleimide monomer (B). Vinyl polymer obtained by polymerizing an aromatic vinyl-maleimide copolymer (1) and a monomer mixture containing at least 85% by weight or more of the aromatic vinyl monomer (A) ( 2).

As described above, the heat-resistant resin composition according to claim 2 of the present invention comprises 50% to 97% by weight of the aromatic vinyl monomer (A) and the maleimide monomer (B). An aromatic vinyl-maleimide copolymer obtained by copolymerizing 3% by weight to 50% by weight and 0% by weight to 20% by weight of another monomer (C) copolymerizable with the above two types of monomers. The composition includes a polymer (1) and an aromatic vinyl polymer (2) obtained by polymerizing a monomer mixture containing at least 85% by weight or more of the aromatic vinyl monomer (A).

As described above, the heat-resistant resin composition according to claim 3 of the present invention has, in addition to the constitution of claim 1 or 2,
The maleimide monomer (B) is N-cyclohexylmaleimide.

As described above, the heat-resistant resin composition according to the fourth aspect of the present invention has an aromatic vinyl-maleimide copolymer (1) and an aromatic vinyl-maleimide copolymer in addition to the constitution of the first, second or third aspect. The group vinyl polymer (2) has a configuration that is thermodynamically compatible with each other.

As described above, the heat-resistant resin composition according to the fifth aspect of the present invention has a maleimide unit content of 1 in the total composition in addition to the constitution according to the first, second or third aspect.
It is configured to be 3% by weight or less.

As described above, the heat-resistant resin composition according to the sixth aspect of the present invention has a turbidity of 10 in the molded article of the heat-resistant resin composition in addition to the constitution of the first, second or third aspect. .
The configuration is 0 or less.

The heat-resistant molded article according to claim 7 of the present invention is
As described above, a molded article obtained by molding the heat-resistant resin composition according to claim 1, 2 or 3, wherein the turbidity is 1
The configuration is 0.0 or less.

Therefore, in the above configuration, heat resistance and moldability can be improved while maintaining high optical properties such as transparency of the aromatic vinyl polymer, and a heat-resistant resin having low water absorption. A composition can be provided. In addition, since the aromatic vinyl-maleimide copolymer (1) and the aromatic vinyl copolymer (2) are thermodynamically compatible with each other, a heat-resistant resin composition having more excellent optical properties is provided. Things can be provided. Moreover, since the content of the maleimide unit in the entire composition is 13% by weight or less, a heat-resistant resin composition having good heat resistance and fluidity and excellent transparency of a molded article is provided. Can be. Furthermore, since the turbidity of the heat-resistant molded article obtained by molding the heat-resistant resin composition is 10.0 or less, it is possible to provide a heat-resistant resin composition more suitable for optical use.

In particular, when the maleimide monomer (B) is N-cyclohexylmaleimide, the aromatic vinyl-maleimide copolymer (1) and the aromatic vinyl polymer (2) are compatible. Further, a heat-resistant resin composition having excellent transparency, low coloring property and heat resistance can be obtained. In this case, the aromatic vinyl monomer (A) is preferably styrene, and by using the maleimide monomer as N-cyclohexylmaleimide, optical properties such as transparency, heat resistance, and moldability. Further, a more excellent heat-resistant resin composition can be obtained due to low water absorption.

As a result, a heat-resistant resin composition having excellent optical properties, heat resistance, moldability and low water absorption can be obtained with the above structure. Therefore, the heat-resistant resin composition of the present invention has an effect that high dimensional accuracy, transparency, heat resistance, and the like are required, and it can be suitably used as a material for automobile parts for optics and the like, and electrical equipment parts. .

Claims (7)

[Claims] 1. An aromatic vinyl-maleimide copolymer (1) obtained by copolymerizing at least an aromatic vinyl monomer (A) and a maleimide monomer (B), and an aromatic vinyl A heat-resistant resin composition comprising: an aromatic vinyl polymer (2) obtained by polymerizing a monomer mixture containing at least 85% by weight of the monomer (A). 2. An aromatic vinyl monomer (A) having a content of 50% by weight or less.
97% by weight, and 3% by weight to 5% of maleimide monomer (B)
Aromatic vinyl-maleimide copolymer (1) obtained by copolymerizing 0% by weight and 0% by weight to 20% by weight of another monomer (C) copolymerizable with the above two types of monomers. ) And an aromatic vinyl polymer (2) obtained by polymerizing a monomer mixture containing at least 85% by weight or more of the aromatic vinyl monomer (A). Stuff. 3. The method according to claim 1, wherein the maleimide monomer (B) is N-cyclohexylmaleimide.
Or the heat-resistant resin composition according to 2. 4. An aromatic vinyl-maleimide copolymer (1) and an aromatic vinyl polymer (2) are thermodynamically compatible with each other. 2
Or the heat-resistant resin composition according to 3. 5. The heat-resistant resin composition according to claim 1, wherein the content of the maleimide unit in the whole composition is 13% by weight or less. 6. The turbidity of a molded article of the heat-resistant resin composition is 10.0 or less.
Or the heat-resistant resin composition according to 3. 7. A molded product obtained by molding the heat resistant resin composition according to claim 1, 2 or 3, wherein the turbidity is 10.
A heat-resistant molded article characterized by being 0 or less.