JPS61272259A - Heat-resistant thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide a composition containing uniformly dispersed N-substituted maleimide and having excellent heat-resistance and impact-resistance, by compounding a copolymer containing N-substituted maleimide with a copolymer of an aromatic vinyl compound and a vinyl cyanide compound. CONSTITUTION:The objective resin composition can be produced by compounding (A) 15-85(wt)% heat-resistant resin obtained by mixing (i) 5-60% latex of a copolymer composed of 15-70% N-substituted maleimide and 30-85% aromatic vinyl compound and (ii) 40-95% latex of a copolymer composed of 50-82% aromatic vinyl compound, 18-50% vinyl cyanide compound and 0-10% other copolymerizable vinyl monomer with (B) 85-15% copolymer obtained by the graft-polymerization of 20-50% vinyl aromatic compound and 5-20% vinyl cyanide compound to 30-65% rubbery polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention relates to a thermoplastic resin having excellent heat resistance and impact resistance. More specifically, the present invention relates to a resin composition containing an N-substituted maleimide.

b. Prior Art A commonly used method for improving the heat resistance of styrene-acrylonitrile copolymers is to replace part or all of styrene with α-methylstyrene. In addition, in order to improve the heat resistance of rubber-modified thermoplastic resins such as ABS resin, some of the graft monomers are
- A method using methylstyrene or a method of mixing an α-methylstyrene-acrylonitrile copolymer and an acrylonitrile-butadiene-styrene copolymer are known. These thermoplastic resins are used as interior materials for automobiles and light electrical equipment, but their heat resistance is still insufficient. Therefore, a method has been proposed to increase the heat resistance by further increasing the content of α-methylstyrene, but when the content of α-methylstyrene increases, many triple chains of α-methylstyrene are generated in the polymer molecule.
Thermal stability during molding deteriorates. As a result, systems using α-methylstyrene naturally have a limit in their heat resistance. Therefore, various studies were conducted to further increase the heat resistance, and it was discovered that the heat resistance could be increased by using N-substituted maleimide.

That is, by mixing a copolymer of an N-substituted maleimide and an aromatic vinyl compound and a copolymer of an aromatic vinyl compound and a vinyl cyanide compound, a thermoplastic resin having excellent heat resistance can be obtained.

Problems to be Solved by the C0 Invention However, in the case of the conventionally known method of mixing both in powder form, it was difficult to uniformly disperse them.

Furthermore, since the copolymer containing N-substituted maleimide has a high glass transition temperature, it is not easy to uniformly disperse the copolymer even when kneaded at a high temperature.

The present inventors have studied to solve the above problems, and have developed a copolymer (A) of an N-substituted maleimide and an aromatic vinyl compound, and a copolymer (B) of an aromatic vinyl compound and a vinyl cyan compound. By mixing in latex state,
It is possible to obtain a resin in which N-substituted maleimide is uniformly dispersed and has excellent heat resistance, and furthermore, by mixing it with a rubber graft, it is possible to obtain a resin with excellent impact resistance and processability. Heading, we arrived at the present invention.

d3 Means for Solving Problems In order to solve the above problems, the present invention provides (i) (a)
Copolymer latex (A) consisting of 15-70% by weight of N-substituted maleimide and 30-85% by weight of aromatic vinyl compound; Copolymer latex (B) consisting of 0 to 10% by weight of other copolymerizable vinyl monomers (A) 5 to 60% by weight, (B) 4
Heat-resistant resin (I) mixed in a proportion of 0 to 95% by weight
(ii) 20-50% by weight of an aromatic vinyl compound, 5-20% by weight of a vinyl cyanide compound, and 30-6% by weight of a rubbery polymer.
Copolymer (II) 1 obtained by graft polymerization of 5% by weight
The object of the present invention is to provide a heat-resistant thermoplastic resin composition containing 5 to 85% by weight.

First, the heat-resistant resin (I) will be described.

The N-substituted maleimide which is a copolymerization component in the copolymer (A) is 15% to 70% by weight, preferably 56 to 70% by weight.
% by weight used. If it is less than 15% by weight, the heat resistance will be lowered, which is not preferable, and if it exceeds 70% by weight, the fluidity will be lowered, which is not preferable.

When the content is in the range of 56 to 70% by weight, products with excellent heat resistance and impact resistance can be obtained. On the other hand, aromatic vinyl compounds have 30
~85% by weight, preferably 30-44% by weight is used. If the aromatic vinyl compound is less than 30% by weight, fluidity will decrease, and if it exceeds 85% by weight, heat resistance will decrease, which is not preferable.

The latex (A) is produced, for example, by emulsion polymerization, in which the aromatic vinyl compound and the N-substituted maleimide are charged into a reactor all at once, and then polymerization is started. After charging the compound, N-
A method of continuously adding part or all of the substituted maleimide, or conversely, a method of continuously adding part or all of the aromatic vinyl compound, or a part of both the aromatic vinyl compound and the N-substituted maleimide. Alternatively, there is a method of continuously preparing all of the ingredients, and any method may be used. The emulsifier used in emulsion polymerization is preferably one that is stable at pH 7 or lower in order to suppress hydrolysis of maleimide. Specifically, anionic emulsifiers such as sodium dodecylbenzenesulfonate and sodium lauryl sulfate are preferably used.

Aromatic vinyl compounds used in the present invention include styrene, ○-methylstyrene, m-methylstyrene, P-methylstyrene,
Methylstyrene, chlorstyrene, dichlorostyrene,
Examples include bromustyrene, dibromustyrene, α-methylstyrene, α-ethylstyrene, methyl-α-methylstyrene, dimethylstyrene, vinylnaphthalene, and the like. Among these, styrene, P-methylstyrene, and ζ-methylstyrene are preferred, and styrene and α-methylstyrene are more preferred.
- methylstyrene or mixtures thereof.

The N-substituted maleimide used in the present invention includes N-
These include phenylmaleimide, N-methylmaleimide, N-ethylmaleimide, Nt-butylmaleimide, N-cyclohexylmaleimide, N-P-chlorophenylmaleimide, N-naphthylmaleimide, and the like. Especially N-
Phenylmaleimide, N-cyclohexylmaleimide,
N-0-methylphenylmaleimide and the like are preferably used.

As a polymerization initiator when producing latex (A),
Ordinary emulsion polymerization initiators are used.For example, persulfate-based polymerization initiators such as potassium persulfate and ammonium persulfate, hydrogen peroxide-based polymerization initiators, and hydroperoxide-based polymerization initiators such as cumene hydroperoxide and diisopropylbenzene hydroperoxide are used. It can be used. As the reducing agent, sulfoxylate formulations, dextrose formulations, etc. can be used.

In the production of latex (A), methods other than the emulsion method include a solution of an N-substituted maleimide copolymer dissolved in a solvent, or a polymer solution obtained by solution polymerization.
For example, latex (A) can be produced by emulsifying using the above-mentioned emulsifier or the like. Among these, it is preferable to manufacture by emulsion polymerization method.

The intrinsic viscosity [η] of the copolymer in the latex (A) is 0
．． 05-0.5 (30℃ in methyl ethyl ketone) d
Preferably, it is 117 g. If it is less than 0.05, impact strength will decrease, and if it exceeds 0.5, fluidity will decrease. Further, the particle size of latex (A) is preferably 5000 Å or less from the viewpoint of uniform mixing and dispersion with latex (B).

The copolymerization components in the latex (B) include an aromatic vinyl compound of 50 to 82% by weight, preferably 70.5 to 82% by weight, and a vinyl cyanide compound of 18 to 50% by weight, preferably 18 to 29.5% by weight. % and 0 to 10% by weight of other copolymerizable vinyl monomers are used. Outside these ranges, physical properties deteriorate, which is not preferable.

The aromatic vinyl compound used in latex (B) is the same monomer as latex (A).

Further, as the vinyl cyanide compound, acrylonitrile, methacrylonitrile, chloroacrylonitrile, etc. are used.

The latex (B) can be produced by a method of emulsifying a copolymer solution obtained by solution polymerization with, for example, the above-mentioned emulsifier, a method of emulsifying a copolymer obtained by suspension polymerization with, for example, the above-mentioned emulsifier, There are methods of producing latex by emulsion polymerization, and any method may be used, but emulsion polymerization is particularly preferred. In order to further improve heat resistance, it is also possible, and particularly preferred, to change the entire amount of aromatic vinyl to α-methylstyrene.

The intrinsic viscosity [η] of the copolymer in latex (B) is 0
．． It is preferably 2 to 0.8 dlt/g, more preferably 0.25 to 0.6 d1/g.

If [η] is too small, the impact strength will be low, and if it is too large, the fluidity will be reduced.

The emulsifier used in the emulsion polymerization of latex (B) is not particularly limited. Further, a common polymerization initiator may be used, and there are no particular restrictions, and the same initiator as used for producing latex (A) may be used.

Latex (A) and latex (B) are mixed until they form a latex state. Even if each latex is solidified and then mixed, the desired effect cannot be obtained.

The amount of latex (A) mixed with latex (B) is 5 to 60% by weight in terms of solid content. If it is less than 5% by weight, heat resistance will be impaired, and if it exceeds 60% by weight, fluidity will be reduced, which is not preferable.

The graft copolymer constituting copolymer (II) is obtained by graft polymerizing 20 to 50% by weight of an aromatic vinyl compound and 5 to 20% by weight of a vinyl cyanide compound to 30 to 65% by weight of a rubbery polymer. be. If the mixing ratio of the monomer mixture to be graft-polymerized is outside the above range, the physical properties of the thermoplastic resin will be impaired, which is not preferable. Further, if the content of the rubbery polymer is less than 30% by weight, the heat resistance will decrease, and if it exceeds 65% by weight, the impact resistance will decrease, which is not preferable.

The aromatic vinyl compound used in copolymer (II) is
The aromatic vinyl compounds mentioned above are used. Further, as the vinyl cyanide compound, the above-mentioned vinyl cyanide compound is also used.

As the rubbery polymer, butadiene rubber, styrene-butadiene copolymer rubber, chloroprene rubber, natural rubber, acrylic rubber, ethylene-propylene copolymer rubber, etc. are used.

The copolymer (II) can be produced by emulsion polymerization in which the monomer mixture is grafted onto a latex of a rubbery polymer, or by a solution polymerization method in which the monomers are grafted in a solution of a rubbery polymer. Any method may be used.

The method of mixing the heat-resistant resin (1) and the copolymer (II) is a method of mixing the heat-resistant resin (I) recovered by the above method and the latex-like copolymer (II) in a latex state;
Alternatively, there is a method of coagulating and recovering (I) and (I[), respectively, and then mixing them in powder form. Either method may be used. (
The mixing ratio of 1) and (If) is 15 to 15% of the heat-resistant resin (1).
85% by weight, and 85-15% by weight of copolymer (II). If the content of (I) is less than 15% by weight, the heat resistance will be low, which is not preferable, and if it exceeds 85% by weight, the processability will be reduced, which is not preferable. In addition, the content of (II) is 15% by weight
If it is less than 85% by weight, the impact resistance will decrease, which is not preferable, and if it exceeds 85% by weight, the heat resistance will decrease, which is not preferable.

In addition to the heat resistant thermoplastic resin of the present invention thus obtained, a thermoplastic resin having further heat resistance, such as polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyacetal, polyamide,
Styrene-maleic anhydride copolymer, polycarbonate, etc. may be mixed.

The present invention will be specifically explained below using Examples.

e. Example Example 1 Heat-resistant resin (1) was synthesized as follows.

20 parts by weight of solid N-phenylmaleimide, 15.0 parts by weight of α-methylstyrene and 0.4 parts by weight of t-dodecylmercaptan were added to 150 parts by weight of ion-exchanged water and 2.0 parts by weight of sodium dodecylbenzenesulfonate. After charging and raising the internal temperature of the flask to 60°C, 0.1 part by weight of sodium ethylenediaminetetraacetate, 0.003 part by weight of ferrous sulfate heptahydrate, and 0.0 parts by weight of IJ formaldehyde sulfoxylate were added. 2 parts by weight of ion-exchanged water 2
0 parts by weight of the solution was added, and 0.1 parts by weight of diisopropylbenzene hydroperoxide was added to start polymerization, and the water bath temperature was maintained at 60° C. for 2 hours. The polymerization conversion rate was 98%. This is latex (A)
shall be.

Separately, 220 parts by weight of ion-exchanged water, 3 parts by weight of sodium dodecylbenzenesulfonate, 71 parts by weight of α-methylstyrene, 29 parts by weight of acrylonitrile, and 0.4 parts by weight of t-dodecylmercaptan were added to adjust the flask internal temperature. After raising the temperature to 60°C, 0.1 part by weight of sodium ethylenediaminetetraacetate, 0.003 part by weight of ferrous sulfate heptahydrate, and 0 part by weight of sodium formaldehyde sulfoxylate.
．． Add a solution of 2 parts by weight dissolved in 20 parts by weight of ion-exchanged water, and add 0 parts by weight of diisopropylbenzene hydroperoxide.
．． 1 part by weight was added to start polymerization, and the water bath temperature was maintained at 60° C. for 3 hours. The polymerization conversion rate was 99%.

This is called latex (B).

Both latexes (^) and (B) thus obtained were mixed at a mixing ratio of (A)/(B) = 35/65 in terms of solid weight, and then subjected to pressure coagulation using calcium chloride. It was solidified, washed with water, dried, and collected. This is referred to as heat-resistant resin (1).

Separately, 60 parts by weight of polybutadiene rubber latex (calculated as solid weight) was added to a flask, 150 parts by weight of ion-exchanged water, 7 parts by weight of styrene, and 3 parts by weight of acrylonitrile were added, and the internal temperature of the flask was raised to 60°C. , sodium birophosphate 0.2 parts by weight, ferrous sulfate heptahydrate 0.01
A solution prepared by dissolving 0.4 parts by weight of Grape II in 20 parts by weight of ion-exchanged water was added, and 0.05 parts by weight of cumene hydroperoxide was added to start polymerization, and the bath temperature was maintained at 70°C. After polymerizing for 1 hour, styrene 21
parts by weight, 9 parts by weight of acrylonitrile, and 0.05 parts by weight of cumene hydroperoxide were continuously added over a period of 3 hours, and polymerization was further carried out for 1 hour to terminate the reaction. The obtained copolymer was coagulated using calcium chloride, washed with water, and dried. This is referred to as copolymer (II).

Heat-resistant resin (I)/copolymer (II) was mixed at a weight ratio of 75/25, pelletized, and then molded by injection. The results of measuring the physical properties of the molded product are shown in Table-■.

Example 2 Latex (8) obtained in Example 1 and latex (B
) mixing ratio (A)/(B) =24.8/75.2(
The procedure was the same as in Example 1 except that the weight of the solid content was changed.

Example 3 Latex (A) and latex (B) obtained in Example 1
) The mixing weight ratio of (A)/(B) = 12.8/87.
The procedure was the same as in Example 1 except that the number was changed to 2.

Example 4 α-methylstyrene 1 in latex (A) of Example 1
The procedure of Example 1 was repeated except that 7.5 parts by weight of α-methylstyrene and 7.5 parts by weight of styrene were used instead of 5 parts by weight.

Example 5 α-methylstyrene 7 in latex (B) of Example 1
The procedure of Example 1 was repeated except that 36 parts by weight of α-methylstyrene and 35 parts by weight of styrene were used instead of 1 part by weight.

Example 6 An AES polymer was produced by the following method.

A homogeneous solution of 5-ethylidene-2- with an iodine value of 15, a Mooney viscosity of 42, and 5-ethylidene-2- as the diene component was prepared in advance into a stainless steel autoclave with an internal volume of 5 i equipped with a ribbon stirring blade.
EPDM containing norbornene (JS manufactured by Japan Synthetic Rubber Co., Ltd.)
REP22) 35 parts by weight, 45.5 parts by weight of styrene, 120 parts by weight of toluene, 0.1 parts by weight of t-dodecylmercaptan
19.5 parts by weight of acrylonitrile, 0.5 parts by weight of benzoyl peroxide, and 0.1 parts by weight of dicumyl peroxide were added, and the temperature was raised to 80°C while stirring. After reaching ℃, the reaction temperature was increased to 8℃.
The polymerization reaction was carried out at a stirring rotation speed of 100 rpm+ while controlling the temperature to be constant at 0°C.

The temperature was raised to 120° C. over 1 hour from 6 hours after the start of the reaction, and the reaction was continued for an additional 2 hours to complete the reaction. The polymerization conversion rate was 97%. After cooling to 100°C, 0.2 parts by weight of 2,2'-methylene-bis(4-methyl-6-t-butylphenol) was added and mixed. The reaction mixture was extracted from the autoclave and evaporated by steam distillation. After distilling off a portion of the unreacted monomer and solvent and finely pulverizing, a 40 mφ vented extruder (220°C, 77
The volatiles were substantially distilled off (00 mHg vacuum) and the polymer was recovered as pellets.

The above graft body (copolymer (■)) and the heat-resistant resin (I) in Example 1 were combined into I/II-57,1/
After mixing at a ratio of 42.9, the mixture was pelletized and molded, and its physical properties were measured.

Comparative Example 1 Latex (A) and latex CB) of Example 1 were coagulated separately, and these and copolymer (II) were mixed at the mixing ratio of Example 1, pelletized, and then molded. Physical properties were evaluated. The results are shown in Table-1. In this way, when powders are mixed together, the impact strength decreases significantly,
It cannot be put to practical use.

10 Effects of the Invention The heat-resistant thermoplastic resin obtained by the present invention can be used in fields requiring heat resistance such as interior parts of automobiles and electrical products.

Claims (4)

[Claims] (1) (i) Copolymer latex (A) consisting of (a) 15-70% by weight of N-substituted maleimide and 30-85% by weight of aromatic vinyl compound and (b) 50-82% by weight of aromatic vinyl compound , a copolymer latex (B) consisting of 18 to 50% by weight of a vinyl cyanide compound and 0 to 10% by weight of other copolymerizable vinyl monomers (A) 5 to 60% by weight, (B) in terms of solid content weight. )4
Heat-resistant resin (I) mixed in a proportion of 0 to 95% by weight
) 15 to 85% by weight and (ii) 20 to 50% by weight of an aromatic vinyl compound and 5 to 20% by weight of a vinyl cyanide compound to 30 to 65% by weight of a rubbery polymer.
Copolymer (II) obtained by graft polymerization to 85% by weight
15% by weight of a heat-resistant thermoplastic resin composition. (2) Claim No. 1, wherein the aromatic vinyl compound is styrene, α-methylstyrene, or a mixture thereof.
The heat-resistant thermoplastic resin composition described in 1. (3) The heat-resistant thermoplastic resin composition according to claim (1), wherein the N-substituted maleimide is N-phenylmaleimide. (4) Latex (A) is N-substituted maleimide 56-
70% by weight and 30-44% by weight of aromatic vinyl compounds
The heat-resistant thermoplastic resin composition according to claim (1), which is a copolymer obtained by copolymerizing.