JPS6173755A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide the titled compsn. having excellent processability and resistance to impact and heat, consisting of a maleimide copolymer and a graft polymer obtd. by polymerizing an arom. vinyl compd. and a rubbery polymer. CONSTITUTION:30-90wt% maleimide copolymer having an intrinsic viscosity of 0.4-1.3 and a Q value (weight-average MW/number-average MW) of 4.0 or below, obtd. by copolymerizing 1-75wt% maleimide (derivative) (a) (e.g. N-phenylmaleimide), 99-25wt% arom. vinyl compd. (b) (e.g. styrene) and 0-50wt% unsaturated carboxylic acid (c) (e.g. acrylonitrile and/or methyl methacrylate) is mixed with 70-10wt% graft polymer having an average parti cle size of 0.05-2mum, a graft ratio of 20-100% and a gel fraction content of 80% or above (ungrafted polymer has an intrinsic viscosity of 0.3-1.3), obtd. by polymerizing 90-20wt% monomer mixture consisting of 40-80wt% compo nent (b) and 60-20wt% component (c) in the presence of 10-80wt% rubbery polymer.

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Object of the Invention The present invention relates to a thermoplastic resin composition having an excellent balance of impact resistance, processability and heat resistance.

α-
Heat-resistant ABS resins containing methylstyrene polymers or maleic anhydride copolymers have been known for a long time (for example, “ABS resins” published by the Society of Polymer Science and Technology in 1971).
Although it is widely used in automobile parts and electrical equipment parts, such heat-resistant ABS resins have the disadvantage of being susceptible to thermal decomposition during molding. Furthermore, as the field of use expands, compositions with even better heat resistance are required.

In recent years, maleimide-based copolymers, which are excellent in heat resistance and thermal decomposition resistance, have attracted attention, but maleimide-based copolymers are significantly inferior in impact resistance and processability. For this reason,
Compositions with improved impact resistance have been proposed by polymerizing maleimide with other vinyl compounds in the presence of a rubbery polymer or by mixing a maleimide copolymer with a graft polymer of rubber and a vinyl compound. However, it still has the problem of poor processability. (Unexamined Japanese Patent Publication No. 57
-167341, JP-A-58-206657, JP-A-5
9-1132'2) On the other hand, compositions with improved processability by mixing a maleimide copolymer with a styrene-acrylonitrile copolymer have been proposed, but they still have problems such as poor impact resistance. are doing. (Unexamined Japanese Patent Publication No. 58-21
7535, Japanese Unexamined Patent Publication No. 58-21.753.7) ■ Structure of the Invention As a result of intensive research in view of the above-mentioned problems, the present inventors have found that:
A composition consisting of a maleimide copolymer and a graft polymer that has excellent impact resistance, processability, and heat resistance by using a maleimide copolymer that has an intrinsic viscosity and a Q value within a specific range. The present invention was achieved by discovering that the following can be obtained.The present invention will be described in detail below.

Maleimide and/or its derivatives constituting the maleimide copolymer include maleimide, methylmaleimide, ethylmaleimide, N-phenylmaleimide, diphenylmaleimide, chlorphenylmaleimide, etc. Kind of-! Or two or more types can be used. Particularly preferred is N-phenylmaleimide alone or a mixture of N-phenylmaleimide and other tumareimides in which N-phenylmaleimide accounts for 50% or more by weight.

one! In addition, aromatic vinyl compounds include styrene, α-
Examples include methylstyrene, P-methylstyrene, and halogenated styrene, and one or more types can be used.

% styrene is preferred.

In addition, examples of unsaturated nitrile compounds and unsaturated carboxylic acid alkyl ester compounds that can be used with the above-mentioned compounds include acrylonitrile, methacrylaterile, fumaronitrile, maleonitrile, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, etc. One type or two or more types can be used. Acrylonitrile and methyl methacrylate are particularly preferred.

The maleimide copolymer used in the present invention includes the above-mentioned maleimide and/or its derivative in a weight range of 1 to 75, an aromatic vinyl compound in a weight range of 99 to 25, and an unsaturated nitrile compound and/or an unsaturated alkyl carboxylate. Consists of 0 to 50% by weight of ester compound. If the composition ratio is outside this range, the object of the present invention cannot be achieved.

The maleimide copolymer can be produced by direct copolymerization of a maleimide compound and a vinyl compound, or by imidization of a copolymer of maleic anhydride and a vinyl compound. Examples of polymerization methods include bulk polymerization, solution polymerization, bulk-suspension polymerization, suspension polymerization, and emulsion polymerization.

Furthermore, what is important in the present invention is the intrinsic viscosity of the copolymer (measured at 30°C in a dimethylformamide solution).
is from 04 to 13, and the Q value (weight average molecular weight/number average molecular weight) is 4.0 or less.

If the intrinsic viscosity is less than 0.4, the mechanical strength will decrease, and if it exceeds 1 or 3, the processability will be markedly poor and the material will not be suitable for molding. 1
However, when the Q value exceeds 40, the mechanical strength decreases.

In terms of mechanical strength, processability, and ease of polymerization, the copolymer preferably has an intrinsic viscosity of 05 to 0.9 and a Q value of 15 to 3.5.

In terms of intrinsic viscosity, methods for obtaining a copolymer with a UKQ value within this range include changing the type and addition of the polymerization catalyst and molecular weight modifier used during copolymerization, or their addition method, polymerization temperature, etc. It will be done.

Note that the Q value can be determined by Kel permeation chromatography.

0 graft polymer (B) The graft fff polymer (B) used in the present invention is a group consisting of an aromatic vinyl compound, an unsaturated nitrile compound, and an unsaturated carboxylic acid alkyl ester compound in the presence of a rubbery polymer. One or more compounds selected from f: This is a Kraft i combination formed by polymerization.

The composition ratio of the rubbery 1 polymer and the polymerization compound is 4! Although there is no limit to the
~80]i' amount ratio, compound (one or more types of maxim 1) 90~2ON amount ratio is preferable. Further, there is no particular restriction on the composition ratio of such compounds, but the ratio of aromatic vinyl compounds to 40 to 8 ON, unsaturated nitrile compounds and /-! , or an unsaturated carboxylic acid alkyl ester compound in an amount of 60 to 20 i.

In addition, in graft polymerization, it is usually difficult to bond (graft) the entire amount of the compound onto the rubbery polymer;
An amount of ungrafted copolymer is produced as a by-product.

In the present invention, not only a true graft polymer in which the ungrafted copolymer is actively separated and removed, but also a single graft polymer containing an ungrafted copolymer may be used. ).

Examples of rubbery polymers include diene rubbers such as polybutadiene, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer, ethylene-propylene copolymer, and ethylene-propylene rubber such as ethylene-propylene-nonconjugated diene copolymer. Rubber, chlorinated polyethylene, acrylic rubber, ethylene-vinyl acetate copolymer, ethylene-
Examples include methyl acrylate copolymers.

Examples of the aromatic vinyl compound include styrene, α-methylstyrene, vinyltoluene, and halogenated styrene, with styrene being preferred. Examples of the unsaturated nitrile compound include acrylonitrile, methacrylaterile, fufuronitrile, 7-rheonitrile, etc., with acrylonitrile being preferred. Examples of the unsaturated carboxylic acid alkyl ester compound include acrylic acid or methacrylic acid ester having a C1-8 alkyl group such as methyl, ethyl, butyl, and methyl methacrylate is preferred.

Craft polymer (B)'! Methods for obtaining i= include known emulsion polymerization methods, suspension polymerization methods, bulk polymerization methods, solution polymerization methods, emulsion-suspension polymerization methods, bulk-suspension polymerization methods, emulsion-bulk polymerization methods, and the like.

There is no restriction on the structure of the kraft polymer (B), but the average particle diameter of the graft M combination is 0.05 to 2 μm.
m1 Craft rate 20-100 cm, gel 80% or more, intrinsic viscosity of ungrafted polymer (dimethylformamide solution,
The composition of the present invention preferably contains a maleimide copolymer (N
and a graft polymer (B), and there are no particular restrictions on their composition ratio, but the balance between impact resistance, processability, and heat resistance is important. ~
It is preferable that the weight ratio is 90 and the graft polymer (B) is 70 to 10 weight ratio.

The zero-mix maleimide copolymer (A) and the graft polymer (B) can be mixed using a known mixer such as a Banbury mixer single-screw extruder.

They can also be mixed in latex form and recovered as a composition.

In addition, known stabilizers, antistatic agents, lubricants,
Additives such as dyes and pigments may be added as appropriate.

In addition, other thermoplastic resins such as polycarbonate, polyester, polyamide, polyphenylene oxide, polyether ether ketone, polyether sulfone, polysulfone, polyoxymethylene, etc. may be blended into the composition of the present invention as appropriate depending on the purpose of use. can do.

Examples will be described below, but the present invention is not limited to these in any way.

Examples 1 to 4 and Comparative Examples 1 to 3 Maleimide copolymer (A) - In an autoclave with a stirrer, 12 Oi parts of deionized water, 2 parts by weight of lauryl sulfate, 2 parts by weight of potassium persulfate, and 2.8 parts by weight of potassium persulfate. After charging 1 part, the compound shown in Table-IVC (
A total of 10% by weight of the mixture) was added, and polymerization was started at 70°C. After the start of polymerization, the remaining compound (mixture) was continuously added over 5 hours.

However, in X-2, the entire amount of n-dodecylmercaptan was added at once at the initial stage of polymerization.

Table 1 shows the intrinsic viscosity and Q value of the obtained copolymer.

Table-1 /=L.

- Graft polymer (B) - In an autoclave with a stirrer, 100 parts by weight of deionized water, polybutadiene (85% gel, weight average particle size 04μ) 5
0 parts by weight (solid content), 35 parts by weight of styrene, 15 parts by weight of acrylonitrile, 2 parts by weight of sodium lauryl sulfate, 0.3 parts by weight of potassium persulfate and 02 parts by weight of t-dodecylmercaptan, and the mixture was heated to 8 parts by weight at 70°C. Time graft polymerization was performed.

The obtained graft polymer had a graft ratio of 48% and a weight average particle diameter of 0.42 μm.

After mixing 70% by weight (solid content) of the maleimide copolymer latex obtained by the above method and 30% by weight (solid content) of the graft polymer latex, the composition was recovered by salting out using magnesium sulfate. The properties of the obtained composition are shown in Table-2.

Table 2 Effects of the invention Among compositions consisting of a maleimide copolymer and a graft polymer, the composition using a copolymer having a specific intrinsic viscosity and Q value has excellent impact resistance, processability, and 0 with heat resistance

Claims (1)

[Claims] 1) Consisting of 1 to 75% by weight of maleimide and/or its derivative, 99 to 25% by weight of aromatic vinyl compound, and 0 to 50% by weight of unsaturated nitrile compound and/or unsaturated carboxylic acid alkyl ester compound, and has an intrinsic viscosity of 0.
．． 4 to 13 and a Q value (weight average molecular weight/number average molecular weight) of 4.0 or less (A
) and a graft polymer (B) obtained by polymerizing a rubbery polymer with one or more selected from the group consisting of an aromatic vinyl compound, an unsaturated nitrile compound, and an unsaturated carboxylic acid alkyl ester compound. Characteristic thermoplastic resin composition.