JPS6151049A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide a polyamide having improved heat distortion temp., mechanical strength and hygroscopicity, by blending a copolymer of p-methylstyrene and maleic anhydride with a polyamide. CONSTITUTION:A thermoplastic resin compsn. consists of 5-60wt% copolymer of p-methylstyrene with maleic anhydride and 95-40wt% polyamide. The p- methylstyrene/maleic anhydride copolymer (PMSM) is a copolymer of methylstyrene containing at least 80% p-methylstyrene with maleic anhydride, and composed of 60-99wt% p-methylstyrene and 40-1wt% maleic anhydride. PMSM can be obtd. by mixing p-methylstyrene with maleic anhydride by stirring under heating. Pref. the copolymerization is carried out in a solvent such as a hydrocarbon or a ketone to obtain a copolymer having good physical properties.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to thermoplastic resin compositions, and more specifically to p.
- A thermoplastic resin composition comprising a methylstyrene copolymer and a polyamide.

Conventional technology Polyamide has excellent chemical resistance, heat resistance, abrasion resistance, etc.
Although it is used in various molded products, it has drawbacks such as large shrinkage during molding, large deterioration of physical properties due to moisture absorption, and low heat distortion temperature during high loading.

In order to improve these drawbacks, copolymers with other polymers and compositions with other polymers are known. For example, a copolymer of a styrene compound which is essentially styrene, an α,β-unsaturated carboxylic acid anhydride which is essentially maleic anhydride, and a polyamide (JP-A-56-5
No. 0931), a composition comprising a styrene-maleic anhydride copolymer resin and a polyamide resin (Japanese Unexamined Patent Publication No. 57
-25355) etc. have been attempted.

Although some of the physical properties such as hygroscopicity, melt viscosity, and molding shrinkage properties have been improved through the above-mentioned attempts, they are still not sufficient when considering the balance with mechanical strength, heat resistance, etc.

Problems to be Solved by the Invention The object of the present invention is to improve the heat distortion temperature, mechanical strength, and hygroscopicity of polyamide.

Means for Solving the Problems Summary of the Invention The summary of the present invention is to provide a thermoplastic resin comprising 5 to 60% by weight of a copolymer of p-methylstyrene and maleic anhydride and 95 to 40% by weight of polyamide. In the composition.

Composition component (1) Copolymer of p-methylstyrene and maleic anhydride The copolymer of p-methylstyrene and maleic anhydride (hereinafter referred to as PMSM) used in the present invention has at least a para-position. It is a copolymer of 80%, preferably 90% or more, more preferably 95% or more methylstyrene and maleic anhydride, and the proportion of p-methylstyrene and maleic anhydride in this copolymer is less than p-methylstyrene and maleic anhydride. 60-99
% by weight, preferably 80-95% by weight, maleic anhydride from 4% to 1% by weight, preferably 20-5% by weight.

FMSM has a weight average molecular weight (My) of approximately 1.0.
00 to about 1 million, preferably about 10,000 to about 300,000, and the molecular weight distribution (MY/Mn) is 1.5 to 40.

Such FMSM can be obtained by mixing and stirring p-methylstyrene and maleic anhydride under heating, but in order to obtain a copolymer with favorable properties, radicals can be prepared in a solvent such as a hydrocarbon or ketone. A method of copolymerization in the presence or absence of a generator is desirable.

Furthermore, PMSM modified with a rubber component may also be used. Rubber component-modified PM8M is produced using butadiene rubber, butadiene-styrene rubber, butadiene-acrylonitrile rubber, isoprene rubber, butyl rubber, isoprene-styrene rubber, inoprene-acrylonitrile rubber, ethylene-propylene copolymer rubber (E
PR), ethylene-propylene-nonconjugated diene ternary 2
It is obtained by copolymerizing in the presence of a rubber component such as synthetic rubber (EPDM).

The proportion of the rubber component in the rubber-modified PM8M is preferably 1 to 20% by weight.

(2) Polyamide Examples of the polyamide used in the present invention include nylon-6, nylon-6,6, and nylon-6,10. These polyamides have a number average molecular weight M (Mn), which is generally about 4. OOO to about so, ooo, but higher values may also be used.

Composition The composition of the present invention comprises 5-60% PMBM, preferably 10-40% by weight, and 95-40% nylon.
, preferably 90 to 601 cm. PMSM is 5
If the amount is less than ft% by weight or less than nylon 40 weight, the object of the present invention cannot be achieved.

The composition is obtained by mixing PMSM and polyamide in the above ratio, but by dispersing both evenly,
In order to make a composition with good properties, melt mixing using a mixing machine such as a Brabender, an extruder, a Panbalimi stamp, or a mixing roll, or a solution kneading method using a solvent that can dissolve both components is possible. desirable.

The compositions of the present invention contain various additives, such as heat stabilizers,
Ultraviolet absorbers, nucleating agents, antistatic agents, coloring agents, and various fillers such as inorganic fillers and plasticizers can be mixed. These additives and the like may be mixed during or after the preparation of the composition.

Effects of the Invention The composition of the present invention has superior mechanical strength and heat resistance compared to polyamide, has a lower water absorption rate, and has better heat resistance than a composition consisting of a styrene-maleic anhydride copolymer and boria 5. and has excellent ductility.

The composition of the present invention has the above-mentioned excellent properties and can be used as a molding material for various industrial products such as automobiles and electrical appliances. It can be easily molded.

Example Hereinafter, the present invention will be explained in detail by way of examples.

Note that "chi" and "part" in the examples are based on weight.

Example 1 Synthesis of PMfilM 100 parts of para-methylstyrene with a purity of 97.04 (the remainder being meta-methylstyrene) was placed in a polymerization vessel equipped with a stirrer and heated to 100°C. To this, 5 parts of maleic anhydride,
2 parts of azobisinobutyronitrile cL and 20 parts of methyl ethyl ketone were continuously added over 8 hours with stirring, and the copolymerization reaction was carried out while maintaining the temperature at 100°C. After the addition of maleic anhydride was completed, stirring was continued at the same temperature for an additional 2 hours. Next, 200 parts of methyl ethyl ketone was added and the mixture was cooled, and the entire solution was poured into 20 times the volume of methanol and alcohol to separate the polymer.

The polymer was dried to have a maleic anhydride portion of 8%, a weight average molecular weight of 224.000, and a number average molecular weight of 9.000.
PM8M of (MY/Mll = 2.29')
i synthesized.

Preparation of Composition 80 parts of PM8M obtained above and 20 parts of nylon-6 (manufactured by Ube Industries, Ltd., Ube Nylon-1013B) were heated at 250°C for 10 minutes in an Uboplasto mill manufactured by Toyo Seiki Seisakusho ■.
The mixture was kneaded for 4 minutes under the conditions of 0 r, p, m to obtain a composition. A test piece was molded from the nine compositions obtained using a hot press, and the physical properties were measured using the following test method, and the results are shown in the table.

MFR (Melt Flow Rate): ASTM D
-1z58 (230°C, 2160r load) Tensile modulus: ASTM D-638 Tensile yield strength 2m STM D-638 Tensile elongation at break: ASTM D-658 Heat distortion temperature l! f
,: ASTM D-648 (1 & 6 kg7cm”
Weight increase rate after immersion in hot water at 80°C for 40 minutes Examples 2 to 5, Comparative Example 1 Same as Example 1 except that the blending ratio of PM8M and nylon-6 was changed. Composition t-Prepared.

Their physical properties were measured and shown in the table.

Comparative Example 2 The physical properties of nylon-6 used in Example 1 were measured and shown in the table.

In place of PM8M obtained in Example 1, styrene-maleic anhydride copolymer (manufactured by Sessui Co., Ltd., Dailarc-232) was used.
, maleic anhydride content: 8%, MW 222,000, M
n92. A composition was prepared in the same manner as in Example 1 or Example 2, except that OOO) (8MA) was used. The physical properties of these compositions were measured and shown in the table.

Example 6 In the same manner as in Example 1, anhydrous maleic fraction 15%, M
W99,000, Mn5? , 000 PM8M t-synthesized.

A composition t- was prepared in the same manner as in Example 1 except that this PM8M t- was used, and its physical properties are shown in the table.

Comparative example 2 100 0 0
37.0 14,800 Example 3 95
5 0 3Q, 4 15,20
0#4 90 10
0 1&6 17,600〃1
8(12001(LO19,70On 2
60 40 0
12.0 2 to 600/15
40 60' Oz
5 24.300 Comparative Example 1 20
80 0 &0 27,000
tr 380 0 2
0 1t7 19,600# 4
60 0 4
G 1 year old 9 201600 Example 6
80 20 0 12.0
19,500 Tensile yield strength Tensile elongation at break Heat deformation temperature Water absorption rate (kg//rn”) (忤)
(℃) (chi) 570 220
64 2.0570 240
70 1.6580 27
0 76 1.2580 24
0 B5 1.0510
35 107 0.5500
1B 108 α25309801,
0

Claims (1)

[Claims] Copolymer of p-methylstyrene and maleic anhydride 5~
A thermoplastic resin composition comprising 60% by weight of polyamide and 95-40% by weight of polyamide.