JPH0598104A - Heat-resistant impact-resistant resin composition - Google Patents

Abstract

PURPOSE:To obtain a resin composition having excellent heat resistance and impact resistance by blending a styrene-maleimide copolymer with a specific graft copolymer having high compatibility with the copolymer and high entanglement density. CONSTITUTION:A resin composition having heat resistance and impact resistance consisting of (A) 10-90 pts.wt. copolymer comprising 90-30mol% vinyl aromatic compound, 10-70mol%, preferably 15-55mol% maleimide compound and 0-30mol% another copolymerizable vinyl compound (e.g. maleic anhydride), (B) 0-50 pts.wt. copolymer (e.g. AS resin) comprising 90-40mol% vinyl aromatic compound and 10-60mol%, preferably 20-55mol% vinyl cyanide compound and (C) 10-50 pts.wt. graft copolymer (e.g. MBS resin) obtained by subjecting C1: 10-90mol%, preferably 10-70mol% butadiene-based rubber elastomer to graft copolymerization with C2: 90-10mol% monomer composed of 0-20mol% vinyl aromatic compound and 100-80mol% methacrylic acid ester.

Description

Detailed Description of the Invention

<Background of the Invention>

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat resistant resin composition having excellent impact resistance. More specifically, the present invention is
Maleimide polymer, so-called AS resin (resin whose typical comonomer is acrylonitrile and styrene) and so-called M
It relates to a blend of a BS resin (a resin whose typical comonomer is methyl methacrylate, butadiene and styrene).

[0002]

2. Description of the Related Art Conventionally, a blend of a styrene-maleimide copolymer and an ABS resin (a resin having acrylonitrile, butadiene and styrene as typical comonomers) has excellent thermal stability and excellent heat resistance. It has impact resistance and workability, and is used for home electric appliances, automobile interior parts and the like which require heat resistance of 100 to 130 ° C. (see Japanese Patent Laid-Open No. 232138/1984).

This blend can obtain high heat resistance by increasing the ratio of the styrene-maleimide copolymer, but on the contrary, it has a drawback of lowering impact resistance. Therefore, the blend of the styrene-maleimide-based copolymer and the ABS resin has a high heat resistance but lacks an impact resistance, so that its application in the market may be limited. This is because the styrene-maleimide copolymer has a larger inter-entanglement molecular weight than the acrylonitrile-styrene copolymer (AS resin) (References 1 and 2), and thus the entanglement density of the blend decreases. Conceivable. It is considered that this is due to the same reason that the impact resistance of the rubber-reinforced polystyrene resin (HIPS) is inferior to that of the ABS resin. References. 1: Y. Aoki, Macromolecules, Vol.23, P.2
309-2312, April 1990 References. 2: S. Wu, Poly. Eng. Sci., Vol.30, No.1
3, P.753-761, 1990

<Outline of the Invention>

DISCLOSURE OF THE INVENTION The present invention aims to solve the problem of insufficient impact resistance found in blends of styrene-maleimide copolymer and AS resin having excellent innate properties. It is intended.

[0005]

The present inventors have found that they have good compatibility with styrene-maleimide copolymers.
Further, by using a graft copolymer obtained by graft-polymerizing a copolymer having a higher entanglement density than the AS resin on the butadiene rubber elastic body instead of the ABS resin or in addition to the AS resin, the above problems are solved. The present invention has been found out and the present invention has been completed. That is, it is intended to increase the entanglement density of the blend by using a copolymer having a higher entanglement density than the AS resin, and to improve impact resistance while maintaining high heat resistance. However, any resin may be used as long as the entanglement density is high, and it is essential that it has good compatibility with the styrene-maleimide copolymer. The present invention selects a specific MBS resin as the resin having a high entanglement density.

<Summary> That is, the heat-resistant and impact-resistant resin composition according to the present invention has the following copolymers A, B and C.
Are each contained in a predetermined amount ratio (provided that the amount ratio of each copolymer is a total amount of 100 parts by weight). .. Copolymer (A): Copolymer 10 to 90 consisting of vinyl aromatic compound residue 90 to 30%, maleimide compound residue 10 to 70% and vinyl compound residue 0 to 30% copolymerizable therewith. Parts by weight Copolymer (B): Copolymer consisting of 90 to 40% of vinyl aromatic compound residue and 10 to 60% of vinyl cyanide compound residue 0 to 50 parts by weight Copolymer (C): butadiene-based Graft copolymer obtained by graft-polymerizing 90 to 10% by weight of a monomer composed of 0 to 20% of vinyl aromatic compound residue and 100 to 80% of methacrylic acid ester compound residue with respect to 10 to 90% by weight of rubber elastic body. Polymer 10 to 50 parts by weight.

<Effect> Instead of AS resin or AS
By using a specific MBS resin with the resin,
In addition to the heat resistance inherently possessed by the styrene-maleimide copolymer, a resin composition having sufficient impact resistance can be obtained.

<Detailed Description of the Invention> The resin composition according to the present invention comprises the copolymers A, B and C in predetermined amounts.

<Copolymer (A)> The copolymer (A) is a copolymer composed of a vinyl aromatic compound, a maleimide compound and a vinyl compound which is optionally used. As vinyl aromatic compounds used in the present invention, styrene and / or side chain-substituted styrene (substituents include lower alkyl, halogen, trihalomethyl, etc.) are generally targeted. Of these, unsubstituted styrene is most common, but α-methylstyrene, p-methylstyrene, t-butylstyrene, halogenated styrene or mixtures thereof can also be used.

As the maleimide compound, substituted or unsubstituted maleimide (substituent is lower alkyl, substituted or unsubstituted phenyl (substituent is lower alkyl, halogen,
Other), halogen, etc.) are generally applicable. N-phenylmaleimide is the most common,
Maleimides, N-alkylmaleimides, N-aromatic derivative maleimides, halogenated maleimide compounds or mixtures thereof can also be used.

As the vinyl aromatic compound and the maleimide compound-copolymerizable vinyl compound used in the copolymer (A), acrylonitrile, acrylic acid esters, methacrylic acid esters, maleic anhydride or a mixture thereof are generally used. Target.

The amount of the maleimide compound residue contained in the copolymer (A) is 10 to 70 mol%, preferably 15 to 55.
Mol% is suitable. If it is less than 10 mol%, the heat resistance is not sufficient, and if it exceeds 70 mol%, the production becomes difficult. The balance of the copolymer (A) is composed of vinyl aromatic compound residues and, if necessary, 30 mol% or less of vinyl compound residues copolymerizable therewith.

The maleimide compound residue may have an imide bond in the monomer state, or may be copolymerized in the form of its precursor (for example, maleic anhydride), and then the imide bond. A bond may be formed.

<Copolymer (B)> The copolymer (B) is a copolymer of a vinyl aromatic compound and a vinyl cyanide compound.

Specific examples of the vinyl aromatic compound used in this copolymer can be found in the examples mentioned above in relation to the copolymer (A). The same or different vinyl aromatic compounds as used for copolymer (A) can be used, but the most common one for copolymer (B) is again styrene.

Acrylonitrile is generally used as the vinyl cyanide compound used in the copolymer (B), but methacrylonitrile or a mixture thereof can also be used.

The content of the vinyl cyanide compound residue in the copolymer (B) is 10 to 60 mol%, preferably 20 to 55.
Mol% is suitable. When the content of the vinyl cyanide compound residue is less than 10 mol% or more than 60 mol%, the compatibility with the copolymer (A) is decreased, and the heat resistance and resistance of the final composition are reduced. Both the impact resistance decreases.

<Copolymer (C)> The copolymer (C) is a graft copolymer obtained by graft-copolymerizing a methacrylic acid ester and optionally a vinyl aromatic compound to a butadiene rubber elastic body. ..

The butadiene rubber elastic material constituting the "stem" of the graft copolymer is butadiene or substituted butadiene (substituent is lower alkyl, especially methyl, halogen,
In particular, a homopolymer of chlorine, etc.) or a predominant amount of the butadiene-based monomer and a copolymerizable vinyl compound (for example, a vinyl aromatic compound, a vinyl cyanide compound, etc. as exemplified above) It is a polymer. Specific examples include polybutadiene, polyisoprene, polylychloroprene, poly (butadiene-styrene), poly (butadiene-acrylonitrile), and others.

The copolymer (C) is formed by grafting "branches" on the above "trunk", and the essential monomer for forming the "branched" polymers is a methacrylic acid ester.

As the methacrylic acid ester compound used for the copolymer (C), a lower alkyl (C1-6, preferably about 1-4) ester of methacrylic acid is generally targeted. Methyl methacrylate is the most common, but ethyl methacrylate, propyl methacrylate, butyl methacrylate or mixtures thereof can also be used.

A vinyl aromatic compound can be used in combination with the above-mentioned methacrylic acid ester as a monomer to form the "branched" polymer of the copolymer (C). Specific examples of the vinyl aromatic compound that can be used can be found in the above-mentioned examples of the copolymer (A). Copolymer (A)
The same or different vinyl aromatic compounds as used in (B) and can be used, but the most common one in copolymer (C) is again styrene.

The amount of the methacrylic acid ester compound residue contained in the graft portion of the graft copolymer (C) is 80.
It is suitable to be at least mol%. If it is less than that, the entanglement density of the copolymer (C) (details described later) becomes less than or equal to the AS resin, and the compatibility with the copolymer (A) decreases, so that the heat resistance and impact resistance of the final composition are reduced. Is reduced.

The content of the butadiene rubber elastic material in the graft copolymer (C) is 10 to 90% by weight, preferably 1
0 to 70% by weight is suitable. When the content of the butadiene-based rubber elastic body in the graft copolymer (C) is less than 10% by weight, the content of the butadiene-based rubber elastic body in the final composition becomes small and sufficient impact resistance can be obtained. Can not be. On the contrary, when the content of the butadiene rubber elastic body in the graft copolymer (C) is more than 90% by weight,
Since the amount of the copolymer grafted on the butadiene rubber elastic body is reduced, the butadiene rubber elastic body is aggregated,
It becomes impossible to obtain sufficient impact resistance.

The graft copolymer as the copolymer (C) is obtained by polymerizing a "branch" polymer monomer in an emulsion of a butadiene rubber elastic body which becomes a "stem" according to a conventional method. Although it is usually produced by such a method, by such a production method, it is unavoidable that a polymer not grafted as a branch is by-produced. Therefore, also in the present invention, the "copolymer (C)" includes the case where such a polymer of a methacrylic acid ester compound and a vinyl aromatic compound which are not grafted coexist.

<Entanglement> One of the features of the present invention is AS.
Since the entanglement density observed in the resin (copolymer (B) in the composition of the present invention) is too low, specifically, the entanglement density is too low, the composition has low impact resistance. As described above, it is a solution to the problem.

In the present invention, the copolymer (C) is selected as a polymer having a high entanglement density in the matrix portion. The copolymer (C) used in the present invention has a matrix entanglement density of 0. .12 mmol / cc or more, preferably 0.13 mmol / cc or more (the upper limit is 0.1.
3 mmol / cc).

Entanglement Density νe (mmol /
cc) is shown by the following formula. Here, G _N is a rubber-like region elastic modulus R is a gas constant T is an absolute temperature (° K) when G _N is measured.

<Composition> The resin composition excellent in heat resistance and impact resistance according to the present invention includes the above-mentioned copolymer (A),
It comprises (B) and (C) in the following quantitative ratios. However, this amount ratio is a value when the total amount of the copolymers (A) to (C) is 100 parts by weight.

When the amount of the copolymer (A) is less than 10 parts by weight, the heat resistance is insufficient, and when it exceeds 90 parts by weight, the impact resistance is lowered. When the copolymers (B) and (C) exceed the above upper limit values, the heat resistance decreases, and when the copolymer (C) is less than the above upper limit values, the impact resistance decreases.

The resin composition according to the present invention falls within the category of thermoplastic resins. Therefore, various auxiliary materials can be blended in a conventional manner for this type of resin composition. Such auxiliary materials include, for example, antioxidants, light stabilizers, antistatic agents, colorants and the like.
If necessary, the copolymers (A) and (C) to the resin composition of the present invention and optionally the copolymer (B)
A compatible thermoplastic resin may be compounded (usually in a small amount) as long as the contribution of (1) is not unduly impaired.

[0032]

【Example】

Example 1 (1) Production of Copolymer (A) and Copolymer (B) 69 kg of styrene and 1.9 kg of maleic anhydride were charged into an autoclave having an internal volume of 300 L, and the temperature was raised to 95 ° C. with nitrogen substitution with stirring. Warmed. To this system, 10 kg of liquid maleic anhydride kept at 70 ° C. was continuously added at a constant addition rate, and bulk polymerization was carried out at 95 ° C. for 460 minutes. Upon completion of continuous addition, the polymerization rate was 44% by weight, and the content of maleic anhydride in the produced polymer was 31 mol%. 21 Kg of acrylonitrile was added to this system over 20 minutes, followed by stirring for another 20 minutes while maintaining the temperature of the system at 90 ° C. At this point, the concentration of maleic anhydride in the monomer was 0.1% or less.

Polyvinyl alcohol suspension 3 is added to this system.
0 g, 30 g of a polyacrylic ester type suspension agent and 70 kg of water containing 300 g of sodium sulfate were added to make a suspension. The temperature of this suspension system is raised to 110 ° C.
After stripping for 0 minutes, 8 kg of acrylonitrile was added. After the temperature was raised to 150 ° C. over 60 minutes, stripping was performed again at this temperature for 120 minutes. Furthermore, 7 kg of aniline and 2 kg of 25% ammonia water.
Was added to carry out an imidization reaction at 155 ° C. for 120 minutes. The obtained bead-like polymer was washed with water, dried, and then pelletized with an extruder. As a result of analyzing the pellets, 76% by weight of a copolymer (A) consisting of 27% by mole of N-phenylmaleimide, 4% by mole of maleimide and 69% by mole of styrene.
And acrylonitrile 41 mol%, styrene 59 mol%
It was found that the copolymer (B) was a mixture of 24% by weight.

(2) Preparation of Copolymer (C) A monomer mixture having a methacrylic acid methyl ester / styrene ratio as shown in Table 1 was added to a styrene-butadiene rubber having an average particle size of 0.4 μm (styrene content: 10% by weight). )
Copolymers C1 and C2 were produced by adding them to the latex and performing emulsion polymerization. The average particle size here is Coulter
The measurement was performed using a Coulter Nanosizer manufactured by Electronics Limited.

Table 1 Copolymer (C) Copolymer C1 Copolymer C2 Composition of rubber elastic body butadiene / styrene butadiene / styrene = 90/10 wt% = 90/10 wt% rubber elastic body content 70 wt% 70 wt% rubber Elastic body dispersed phase _{0.4 μm 0.4 μm} average particle size Methyl methacrylate ester _{81/19 mol% 90/10 mol%} Lu / styrene (weight ratio) Entanglement density νe _{0.13 0.15} (mmol / cc)

(3) Measurement of Entanglement Density The graft copolymer (C) was dissolved in acetone and the matrix component was extracted using a centrifuge. Re-precipitate this in methanol and dry it thoroughly before press molding.

Therefore, a disk-shaped sample having a thickness of 1 mm and a diameter of 25 mm was prepared. Rheometrics, DYNAMIC ANALYZERRDA
Using II, in a 160 ° C atmosphere, frequency 0.01-10
Dynamic viscoelasticity was measured in the range of 00 rad / s. The entanglement density νe was calculated by using the dynamic storage elastic modulus G ′ at the frequency where the loss tangent tan δ is the minimum in the rubber-like region as the rubber-like region elastic modulus G _N. The calculation method was according to the above-mentioned formula.

Examples 1 to 4 Copolymers (A), (B) and (C) were blended at the compounding ratios shown in Table 2 by an extruder and kneaded into pellets. Table 2 shows the physical properties of the obtained mixture.

[0039]

[Table 1]

Comparative Examples 1 to 6 Instead of the copolymer (C), a monomer mixture as shown in Table 3 was added to the same rubber latex as the copolymer (C) to produce a copolymer (D). did. The copolymer D1 is a general ABS resin, and the copolymers D2 and D3 are copolymers different from the copolymer (C) only in the ratio of methacrylic acid methyl ester / styrene. Entanglement Density νe of Copolymer (D)
Was also measured in the same manner as the copolymer (C).

[0041] Table 3 copolymer (D) a copolymer D1 copolymer D2 copolymer D3 rubber elastic body composition butadiene / styrene butadiene / styrene butadiene / styrene Len = 90/10 wt% Len = 90/10 wt% Len = 90/10 wt% rubber elastomer content 70wt% 70wt% 70wt% composition of the rubber elastic body dispersed phase _{0.4 .mu.m 0.4 .mu.m 0.4 .mu.m} average particle diameter monomers styrene / acrylate methacrylate methylol methacrylic acid methylate adding the Ronitoriru glycol ester / Styl ester / Sti = 54 / 46mol% Ren = 47 / 53mol% Ren = 61 / 39mol% Entanglement density νe _{0.12 0.10 0.11} (mmol / cc) Copolymer (at the compounding ratio shown in Table 4 ) A), (B) and D) were kneaded and pelletized by an extruder. The physical properties of the obtained mixture are shown in Table 4 as a comparative example.

[0042]

[Table 2]

Example 2 and Comparative Example 1, Example 4 and Comparative Example 4
As can be seen by comparing with, the resin composition of the present invention has the same heat resistance and moldability as that of the conventional blend of the styrene-maleimide copolymer and the ABS resin, but the impact resistance can be improved. it can. Further, comparing Examples 1 and 2 with Comparative Examples 2 and 3 and Examples 3 and 4 with Comparative Examples 5 and 6, the content of the methacrylic acid ester compound residue in the graft copolymer (C) was small and the entanglement density was low. Of low
It can be seen that the impact resistance is also low.

[0044]

EFFECTS OF THE INVENTION The fact that a resin composition having the heat resistance inherently possessed by a styrene-maleimide copolymer and also having excellent impact resistance can be obtained means that "means for solving the problem" is mentioned. As described above in.

Claims (1)

[Claims] 1. A heat-resistant and impact-resistant resin composition characterized by comprising the following copolymers A, B and C in a predetermined amount ratio (provided that each copolymer is used). The amount ratio of is based on a total amount of 100 parts by weight). Copolymer (A): Copolymer 10 to 90 consisting of vinyl aromatic compound residue 90 to 30%, maleimide compound residue 10 to 70% and vinyl compound residue 0 to 30% copolymerizable therewith. Parts by weight Copolymer (B): Copolymer consisting of 90 to 40% of vinyl aromatic compound residue and 10 to 60% of vinyl cyanide compound residue 0 to 50 parts by weight Copolymer (C): butadiene-based Graft copolymer obtained by graft polymerizing 90 to 10% by weight of a monomer composed of 0 to 20% of vinyl aromatic compound residue and 100 to 80% of methacrylic acid ester compound residue with respect to 10 to 90% by weight of rubber elastic body. Polymer 10 to 50 parts by weight.