JPH07278401A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To produce the subject composition improved in heat resistance by mixing a specified p-methoxyphenylmaleimide copolymer with a specified styrene/acrylonitrile graft copolymer and a specified styrene/acrylonitrile copolymer. CONSTITUTION:This resin composition is prepared by mixing 1-70wt.% maleimide copolymer comprising 35-65wt.% styrene units, 35-65wt.% p- methoxyphenylmaleimide units and 0-10wt.% units of another vinyl monomer such as acrylic acid with 20-60 wt. % graft copolymer prepared by grafting 35-65 wt. % mixture comprising 60-80wt.% styrene monomer, 20-40wt.% acrylonitrile monomer and 0-10wt.% other vinyl monomers onto 35-65wt.% rubbery polymer and 0-70wt.% styrene/acrylonitrile copolymer comprising 60-80wt.% styrene units, 20-40wt.% acrylonitrile units and 0-10wt.% other vinyl monomer units.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a thermoplastic resin composition having excellent heat resistance, impact resistance and improved chemical resistance. The composition of the present invention is an automobile interior. It can be suitably used for parts, home electric appliances parts, various heat appliance parts, and the like.

[0002]

2. Description of the Related Art Conventionally, a blend composition of a styrene-maleimide copolymer and an ABS resin (maleimide AB
The S resin composition) is known to have excellent thermal stability and good heat resistance (USP 365117).
No. 1, USP 3652726, JP-A-5
7-98536, JP-A-57-125242, JP-A-58-101141 and JP-A-58-1.
29043).

Generally, a maleimide-based ABS resin composition is a blend composition of an α-methylstyrene-acrylonitrile copolymer and an ABS resin (α-methylstyrene-based ABS resin composition) in terms of heat stability, heat resistance and moldability. However, it was inferior in impact resistance. However, a maleimide-based ABS resin composition having improved impact resistance has also become known (JP-A-59-23).
2138, JP-A-61-73755, JP-A-61-101547).

Further, the maleimide-based ABS resin composition is
It is also known that it is superior in gasoline resistance to conventional ABS resins and modified PPO resins (JP-A-60-21).
2449). However, the conventionally proposed maleimide-based ABS resin composition has insufficient chemical resistance depending on the molded product used, and often causes cracking when the molded product comes into contact with a chemical. was there.

Therefore, a composition in which a partially crystalline resin such as a polyamide resin or a polyester resin is blended with a maleimide-based ABS resin composition to improve chemical resistance is also known (Japanese Patent Laid-Open No. 62-22844). Publication, JP-A-6
3-17949). However, since these compositions contain a partially crystalline resin, the performance of obtaining a molded product free from dimensional stability and warpage, which is one of the excellent features of the maleimide-based ABS resin composition, is lost. There was a problem that it would end up.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to maintain the excellent performance of the maleimide-based ABS resin composition as described above and to solve the problems. That is, it is intended to improve the chemical resistance while maintaining the excellent heat resistance, heat stability, moldability, dimensional stability, low warpage and impact resistance of the maleimide-based ABS resin composition.

[0007]

Means for Solving the Problems The present invention uses a specific maleimide-based copolymer to prevent the heat resistance, the compatibility with the ABS graft copolymer and the AS resin from being impaired.
It is intended to provide a maleimide-based ABS resin composition having excellent impact resistance and improved chemical resistance. That is, the present invention is the component (A); styrene unit 35 to 65% by weight,
Paramethoxyphenylmaleimide unit 35-65% by weight
And 10 to 70% by weight of a copolymer consisting of 0 to 10% by weight of a copolymerizable vinyl monomer unit, and component (B);
Rubbery polymer 35 to 65% by weight to styrene monomer 60 to
80% by weight, acrylonitrile monomer 20-40% by weight
And 20 to 60% by weight of a graft copolymer obtained by copolymerizing 35 to 65% by weight of a monomer mixture consisting of 0 to 10% by weight of a copolymerizable vinyl monomer, and (C) component; a styrene unit 60. ~ 80 wt%, acrylonitrile unit 2
0 to 70% by weight of a copolymer consisting of 0 to 40% by weight and 0 to 10% by weight of another copolymerizable vinyl monomer unit,
Is a thermoplastic resin composition.

The present invention will be described in detail below. First, the copolymer of the component (A) of the present invention and the production method thereof will be described.
As a first production method, after copolymerizing a styrene monomer, a maleic anhydride monomer and another copolymerizable vinyl monomer mixture, paramethoxyaniline is reacted to convert the maleic anhydride group to paramethoxyphenyl. As a second method, a styrene monomer,
Examples thereof include a method in which a para-methoxyphenylmaleimide monomer and another copolymerizable vinyl monomer mixture are copolymerized, and a maleimide copolymer can be obtained by any method.

Other copolymerizable vinyl monomers include vinyl cyanide monomers such as acrylonitrile and methacrylonitrile, acrylic acid ester monomers such as methylacrylic acid ester and ethylacrylic acid ester, and methylmethacrylic acid. Esters, methacrylic acid ester monomers such as ethyl methacrylic acid ester, vinylcarboxylic acid monomers such as acrylic acid and methacrylic acid, unsaturated dicarboxylic acid imide derivative compounds such as N-phenylmaleimide and N-methylmaleimide, and acrylic acid Examples thereof include amide and methacrylic acid amide. Further, in the second production method, maleic anhydride is further included in the above-mentioned monomers. In the first production method, the maleic anhydride group remaining without being converted into the para-methoxyphenylmaleimide group can be introduced into the copolymer. Of course, these monomers are 1
One kind or two or more kinds can be used.

The copolymer can also be copolymerized in the presence and absence of a rubbery polymer. Examples of the rubber-like polymer include a butadiene polymer, a butadiene-styrene copolymer, an ethylene-propylene copolymer, an ethylene-propylene-gen copolymer, and an acrylic acid ester polymer.

In the case of the first production method, bulk-suspension polymerization, solution polymerization and bulk polymerization, and in the case of the second production method, suspension polymerization,
Known polymerization methods such as emulsion polymerization, solution polymerization and bulk polymerization can be used.

The copolymer of the component (A) has a styrene unit of 3
5 to 65% by weight, p-methoxyphenylmaleimide units 35 to 65% by weight and other copolymerizable vinyl monomer units 0 to 10% by weight. More preferably, it is a copolymer composed of 40 to 60% by weight of a styrene unit, 40 to 60% by weight of a paramethoxyphenylmaleimide unit, and 0 to 10% by weight of another copolymerizable vinyl monomer unit.

If the amount of styrene units is less than 35% by weight, moldability is poor, and if it exceeds 65% by weight, heat resistance is impaired. The amount of paramethoxyphenylmaleimide units was 35.
If it is less than 5% by weight, heat resistance and chemical resistance are poor, and if it exceeds 65% by weight, moldability and impact strength are impaired. On the other hand, if the amount is out of these ranges, the compatibility with the component (B) and the component (C) becomes poor, the impact strength is extremely lowered, a peeling phenomenon occurs, and the chemical resistance is lowered.

Other copolymerizable vinyl monomer units are
An amount of 10% by weight or less can be copolymerized as long as the compatibility with the components (B) and (C) is not impaired.

Next, the graft copolymer of the component (B) of the present invention and the method for producing the same will be described. Examples of the rubbery polymer used as the component (B) include a butadiene polymer, a butadiene-styrene copolymer, an ethylene-propylene copolymer, an ethylene-propylene-gen copolymer, and an acrylic acid ester polymer. .

Other copolymerizable vinyl monomers include vinyl cyanide monomers such as methacrylonitrile, acrylic acid ester monomers such as methyl acrylic acid ester and ethyl acrylic acid ester, and methylmethacrylic acid ester. Methacrylic acid ester monomers such as ethyl methacrylic acid ester, vinylcarboxylic acid monomers such as acrylic acid and methacrylic acid, unsaturated dicarboxylic acid imide derivative compounds such as N-phenylmaleimide and N-methylmaleimide, and acrylic acid amides, Examples thereof include methacrylic acid amide and maleic anhydride.

For the polymerization, any known polymerization technique can be adopted, for example, aqueous heterogeneous polymerization such as suspension polymerization and emulsion polymerization, bulk polymerization, solution polymerization and precipitation polymerization of the produced polymer in a poor solvent. There is. Emulsion polymerization is preferred from the viewpoint of easy control of the rubber particle size.

The method for producing the graft copolymer of the component (B) is as follows:
Styrene monomer 60 to 80% by weight, acrylonitrile monomer 20 to 4 in the presence of the rubbery polymer 35 to 65% by weight.
0% by weight and 0 to 10 other copolymerizable vinyl monomers
It is obtained by graft-copolymerizing 35 to 65 wt% of a monomer mixture consisting of wt%. More preferably, the styrene monomer 65 to 7 in the presence of 40 to 60% by weight of the rubber-like polymer.
A graft copolymer is a monomer mixture consisting of 8% by weight, 22 to 35% by weight of acrylonitrile monomer, and 0 to 10% by weight of other copolymerizable vinyl monomer.

If the composition of the component (B) deviates from the above range, the compatibility with the component (A) becomes poor, and the impact strength and the chemical resistance decrease.

Next, the copolymer of the component (C) of the present invention and the method for producing the same will be described. As the other copolymerizable vinyl monomer as the component (C), the same monomer as used for obtaining the graft copolymer as the component (B) can be used. Polymerization methods include suspension polymerization, emulsion polymerization, solution polymerization,
A known polymerization method such as bulk polymerization can be used.

The copolymer of the component (C) is composed of 6 styrene units.
0 to 80% by weight, acrylonitrile units 20 to 40% by weight, and other copolymerizable vinyl monomer units 0 to 10% by weight. More preferably, styrene units 65-7
It is a copolymer composed of 8% by weight, 22 to 35% by weight of acrylonitrile unit, and 0 to 10% by weight of other copolymerizable vinyl monomer unit. If it deviates from this range, the compatibility with the component (A) becomes poor, and impact strength and chemical resistance decrease.

Next, in the thermoplastic resin composition of the present invention, the respective components are mixed in proportions of 10 to 70% by weight of the component (A), 20 to 60% by weight of the component (B) and of the component (C). It is 0 to 70% by weight. Component (A) is preferably 20-
50% by weight, the component (B) is 30 to 50% by weight, and the component (C) is 0 to 50% by weight. The mixing ratio is selected according to the required heat resistance, impact strength, moldability and chemical resistance, but if the amount of the component (A) is less than 10% by weight, the heat resistance is insufficient and the chemical resistance is low. Is not seen. Also,
If it is more than 70% by weight, the impact strength is significantly lowered.

The thermoplastic resin composition of the present invention is a mixture of the above-mentioned component (A), component (B) and component (C), but the mixing method is not particularly limited, and known means may be used. Can be used. As a means thereof, known devices such as a Henschel mixer and a tumbler mixer can be used for premixing before kneading with an extruder, and further, a Banbury mixer, a mixing roll, a kneader, a single-screw / multi-screw extruder. Examples of the method include melt mixing using the above. Further, a single-screw or twin-screw extruder equipped with a devolatilization device can be preferably used for the purpose of reducing volatile components in the resin composition.

In addition to the thermoplastic resin composition of the present invention, antioxidants, ultraviolet absorbers, flame retardants, plasticizers, lubricants, colorants, glass fibers, carbon fibers, calcium carbonate, talc, mica, and other fillers. Can be added according to the purpose.

The thermoplastic resin composition of the present invention is extruded,
It can be molded by molding methods such as injection molding and compression molding, and the resulting molded article has excellent heat resistance, impact resistance and chemical resistance, so it can be used for household electrical appliances, automobile parts, food containers, etc. It is useful.

[0026]

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. All parts and% in the examples are expressed by weight.

Experimental Example 1 Component (A): Preparation of Maleimide Copolymer-1 In a reaction can equipped with a stirrer, 100 parts of styrene and 0.1 part of α-methylstyrene dimer were charged, and the inside of the reaction can was replaced with nitrogen. Then, after raising the temperature to 83 ° C., maleic anhydride 6
A solution prepared by dissolving 7 parts and 0.2 part of benzoyl peroxide in 400 parts of methyl ethyl ketone was added over 8 hours.
After the addition, the temperature was kept at 83 ° C. for another 3 hours to complete the polymerization. Subsequently, 235 parts of a solution prepared by dissolving 84 parts of paramethoxyaniline in 150 parts of methyl ethyl ketone and 2 parts of triethylamine were added, and the temperature was raised to 140 ° C. and the reaction was carried out for 7 hours. The reaction solution was devolatilized with an extruder equipped with a devolatilizer to obtain a maleimide copolymer A-1.

Experimental Example 2 Component (A): Production of Maleimide Copolymer-2 A reaction vessel equipped with a stirrer was charged with 50 parts of styrene, 5 parts of acrylonitrile and 0.1 part of α-methylstyrene dimer. After substituting the inside with nitrogen and raising the temperature to 83 ° C., a solution of 40 parts of paramethoxymaleimide, 5 parts of N-phenylmaleimide and 0.2 part of benzoyl peroxide dissolved in 400 parts of methyl ethyl ketone was added in 8 hours. . After the addition, the temperature was kept at 83 ° C. for another 3 hours to complete the polymerization. Subsequently, the reaction liquid was subjected to a devolatilization treatment with an extruder equipped with a devolatilization device to obtain a maleimide copolymer A-2.

Experimental Example 3 Component (A): Production of Maleimide Copolymer-3 A reaction vessel equipped with a stirrer was charged with 50 parts of styrene, 5 parts of acrylonitrile and 0.1 part of α-methylstyrene dimer. After substituting the inside with nitrogen and raising the temperature to 83 ° C., a solution prepared by dissolving 10 parts of paramethoxymaleimide, 35 parts of N-phenylmaleimide and 0.2 part of benzoyl peroxide in 400 parts of methyl ethyl ketone was added over 8 hours. . After the addition, the temperature was maintained at 83 ° C. for 3 hours to complete the polymerization. Subsequently, the reaction liquid was subjected to a devolatilization treatment with an extruder equipped with a devolatilization device to obtain a maleimide copolymer A-3.

Experimental Example 4 Component (A): Production of Maleimide Copolymer-4 In a reaction can equipped with a stirrer, 80 parts of styrene was charged, the inside of the reaction can was replaced with nitrogen, and the temperature was raised to 83 ° C. Then, a solution prepared by dissolving 20 parts of paramethoxymaleimide and 0.3 part of benzoyl peroxide in 400 parts of methyl ethyl ketone was added over 8 hours. After the addition, the temperature was maintained at 83 ° C. for 3 hours to complete the polymerization. Subsequently, the reaction liquid was subjected to a devolatilization treatment with an extruder equipped with a devolatilization device to obtain a maleimide copolymer A-4. Table 1 shows composition analysis by C-13 NMR analysis of A-1 to A-4, weight average molecular weight by gel permeation chromatography (GPC) using standard polystyrene as a calibration curve, and glass transition temperature by DSC measurement. showed that.

Experimental Example 5 Component (B): Preparation of graft copolymer Polybutadiene latex 8 was placed in a reactor equipped with a stirrer.
0 part (solid content 50%, average particle size 0.35 μm), sodium stearate 1 part, sodium formaldehyde sulfoxylate 0.1 part, tetrasodium ethylenediamine tetraacetic acid 0.03 part, ferrous sulfate 0.0
03 parts and 200 parts of pure water were charged and heated to 65 ° C., and 40 parts of a monomer mixture consisting of 25% acrylonitrile and 75% styrene, t-dodecyl mercaptan 0.
4 parts of 3 parts and 0.2 parts of tertiary peroxyacetate
Polymerization was carried out at 65 ° C. for 2 hours after the addition was completed. After adding an antioxidant to the obtained reaction solution, it was coagulated with calcium chloride, washed with water and dried to obtain a white powdery graft copolymer B-1. Table 2 shows the graft ratio of B-1, the compositional analysis and the weight average molecular weight of the ungrafted component.

In order to measure the grafting ratio of B-1 and the molecular weight of the ungrafted copolymer, a certain amount of B-1 was swollen in a methyl ethyl ketone (MEK) solution, and the supernatant solution obtained by centrifugation was used to prepare the ungrafted copolymer. Styrene
An acrylonitrile copolymer was used, and its composition was analyzed by GPC weight average molecular weight and Kjeldahl nitrogen quantitative analysis. Further, the weight of the rubber component was determined by the halogen addition method using the MEK insoluble matter settled by centrifugation, and the graft ratio was determined by the following formula. Graft ratio = [(MEK insoluble content weight-rubber content weight) / rubber content weight)] x 100 (%)

Experimental Example 6 Component (C): Production of Copolymer-1 In a reaction can equipped with a stirrer, 100 parts of pure water and 2 parts of tricalcium phosphate were charged, followed by 75 parts of styrene and 25 parts of acrylonitrile. Benzoyl peroxide 0.2
After a portion was charged and the inside of the reaction vessel was replaced with nitrogen, the temperature was raised to 80 ° C. and polymerization was carried out for 8 hours. The obtained reaction liquid was neutralized with hydrochloric acid, dehydrated and dried to obtain a copolymer C-1.

Experimental Example 7 Component (C): Production of Copolymer-2 The same operation as in Experimental Example 6 was carried out except that 80 parts of styrene and 20 parts of acrylonitrile were used in the production of Experimental Example 6,
The copolymer C-2 was obtained. Table 3 shows the compositional analysis of C-1 and C-2 by the Kjeldahl nitrogen analysis and the weight average molecular weight value by GPC.

[0035]

[Table 1]

[0036]

[Table 2]

[0037]

[Table 3]

The copolymers obtained in Experimental Examples 1 to 7 were mixed in a tumbler mixer for 10 minutes at the ratios shown in Table-4, Table-5 and Table-6, and then the two copolymers with a vent having a diameter of 35 mm were used. The mixture was melt-kneaded with a shaft extruder at a temperature of 270 ° C. to prepare pellets. The pellets were injection molded at a temperature of 260 ° C. to prepare test pieces, and the physical properties were evaluated according to the following evaluation methods. The test piece for the chemical resistance test was prepared by press-molding pellets at a temperature of 270 ° C. in order to eliminate the influence of molding strain. The evaluation results are shown in Table-4, Table-5 and Table-6.

[0039]

[Table 4]

[0040]

[Table 5]

[0041]

[Table 6]

The evaluation method is as follows. (1) Heat resistance; Vicat softening point (VSP) according to JIS K
According to 6874, it was measured with a load of 5 kg. (2) Impact resistance; Izod impact strength (IZOD) is A
According to STM D256, a notched test piece having a thickness of 1/8 inch was measured at a temperature of 23 ° C. (3) Chemical resistance: A test piece of 330 × 20 × 2 mm was measured by the Bergen 1/4 ellipse method with a long radius of 248 mm and a short radius of 148 mm, using salad oil and kerosene as chemicals, and the criticality after 24 hours at a temperature of 23 ° C. The amount of strain was measured. Incidentally, if the critical strain amount is generally 0.6% or more, it can be judged that the molded article of the resin composition of the present invention has good chemical resistance. (4) Presence / absence of warpage: A 200 × 200 × 2 mm square plate was injection-molded and then placed on a flat test bench for one day and the state of the warpage of the square plate was observed.

As is clear from the results shown in Table 4, the compositions of Examples 1 to 3 had a large amount of critical strain with respect to chemicals,
It has excellent chemical resistance, as well as excellent heat resistance and impact resistance.

On the other hand, as shown in Table 5 and Table 6, in the composition of Comparative Example 1, the composition of the maleimide copolymer as the component (A) was out of the range of the present invention (paramethoxyphenylmaleimide). The number of units is less than specified, and other copolymerizable vinyl monomer units are many), and the chemical resistance is poor.

In the composition of Comparative Example 2, the composition of the maleimide copolymer as the component (A) was outside the range of the present invention (the styrene unit was more than the specified amount, and the paramethoxyphenylmaleimide unit was less than the specified amount). Poor heat resistance, impact strength and chemical resistance.

In the composition of Comparative Example 3, the composition of the styrene-acrylonitrile copolymer as the component (C) was outside the scope of the present invention (more styrene units and less acrylonitrile units than specified), impact strength, Poor chemical resistance.

In the composition of Comparative Example 4, the amount of the maleimide copolymer as the component (A) is larger than the range of the present invention, and the impact strength is poor.

The composition of Comparative Example 5 contained less amount of the maleimide copolymer as the component (A) than the range of the present invention, and was inferior in heat resistance and chemical resistance.

The composition of Comparative Example 6 is a composition containing polyamide 6, and warpage occurs in the molded product.

[0050]

EFFECT OF THE INVENTION The thermoplastic resin composition of the present invention contains a specific maleimide copolymer and a graft copolymer having a specific composition compatible with the maleimide copolymer, and a styrene-acrylonitrile copolymer, in combination with a chemical resistance. The sex is improved. Moreover, it has excellent heat resistance and impact resistance, and is suitable for automobile interior parts, home electric appliance parts, various heat appliance parts, etc., which require these performances, and has an extremely great industrial value.

Claims (1)

[Claims] 1. Component (A): 35 to 65% by weight of styrene unit and 35 to 65 of paramethoxyphenylmaleimide unit.
% By weight and other copolymerizable vinyl monomer units 0 to 1
10 to 70% by weight of a copolymer consisting of 0% by weight, (B)
Ingredients: 35 to 65% by weight of rubber-like polymer, 60 to 80% by weight of styrene monomer, and 20 to 40 of acrylonitrile monomer
20 to 60% by weight of a graft copolymer obtained by copolymerizing 35 to 65% by weight of a monomer mixture consisting of 0 to 10% by weight and 0 to 10% by weight of another copolymerizable vinyl monomer, and (C) component: styrene. A thermoplastic resin composition comprising 60 to 80% by weight of a unit, 20 to 40% by weight of an acrylonitrile unit, and 0 to 70% by weight of a copolymer comprising 0 to 10% by weight of another copolymerizable vinyl monomer unit.