JPS5971353A - thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide a thermoplastic resin composition having excellent impact resistance, heat-deformation resistance and weather resistance, by mixing a vinyl chloride resin with an EPDM-based impact modifier and an alpha-methylstyrene/ acrylonitrile copolymer. CONSTITUTION:The objective composition (100pts.wt.) is prepared by mixing (A) 55-90pts.wt. of a vinyl chloride resin having an average polymerization degree of 400-2,000, (B) 5-40pts.wt. of an impact modifier obtained by the graft polymerization of an aromatic vinyl compound, a vinyl cyanide, a methacrylic acid ester, etc. to an ethylene/propylene/non-conjugated diene copolymer (the amount of the rubber component is usually 5-60wt% based on 95-40wt% of the vinyl compound), and (C) 5-40pts.wt. of an alpha-methylstyrene/acrylonitrile copolymer composed of 60-90wt% of alpha-methylstyrene and 10-40wt% of acrylonitrile.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a vinyl chloride resin composition that has excellent impact resistance, heat deformation resistance, and weather resistance.

Although vinyl chloride resins have excellent properties such as weather resistance, chemical resistance, and flame retardancy, they have drawbacks such as impact resistance and heat deformation resistance. In order to improve these drawbacks, various proposals have been made in the past. For example, a typical method to improve impact resistance is to blend ABS resin or MBS resin, but this method has a major drawback in weather resistance. be.

On the other hand, in consideration of weather resistance, chlorinated polyethylene, graft copolymer obtained by grafting vinyl chloride onto ethylene/vinyl acetate copolymer, acrylic rubber, ethylene-propylene-nonconjugated diene copolymer rubber (hereinafter referred to as EPDM) There is a method of blending impact modifiers such as those of the above-mentioned type, but although satisfactory impact resistance and weather resistance can be obtained, the heat deformation resistance decreases.

In general, there is no known polymer blend system that improves the impact resistance and at the same time greatly improves the heat deformation resistance of vinyl chloride resins without impairing their weather resistance.

As a result of intensive study, the present inventors found that vinyl chloride resin and
It has been discovered that a resin composition with excellent impact resistance, weather resistance, and heat deformation resistance can be obtained by creating a ternary mixture system of an EPDM-based impact modifier and an α-methylstyrene-acrylonitrile copolymer. Ta.

That is, the composition of the present invention comprises 55 to 90 parts by weight of a vinyl chloride resin, 5 to 40 parts by weight of an EP6M impact modifier, and 5 to 40 parts by weight of α-methylstyrene-acrylonitrile copolymer. By mixing, cross-wiring, and molding the composition, a molded article with good impact resistance, weather resistance, and heat deformation resistance can be obtained.

Furthermore, the composition of the present invention has excellent chemical resistance and flame retardancy,
Moreover, it is characterized by excellent moldability such as vacuum moldability, injection moldability, and extrusion moldability.

The vinyl chloride resin used in the present invention may be a copolymer of vinyl chloride homopolymer containing a small amount of vinyl chloride (at least 75% by weight and ta).

Furthermore, the average degree of polymerization of the vinyl chloride resin varies depending on the molding method, but is generally used to have an average degree of polymerization of about 400 to 2,000.

EPDM-based impact modifiers include EPDM, aromatic vinyl,
It is a graft copolymer obtained by graft polymerizing compounds such as vinyl cyanide and methacrylic acid ester.

Note that vinyl chloride, vinylidene chloride, etc. may be used instead of aromatic vinyl, vinyl cyanide, and methacrylic acid ester.

EPDM is a copolymer rubber of ethylene, propylene-non-conjugated diene, and contains 5-methylene-2-norbornene, 5-ethythelene-2-norbornene, 5-impropylidene-2-norbornene, 5-impropylidene-2-norbornene, and 5-impropylidene-2-norbornene. −
Norbornenes such as vinyl-2-norbornene, cyclopentadienes such as cyclopentadiene and dicyclopentadiene, and chain dienes such as 1,4-hexadiene are used. As the aromatic vinyl compound, styrene, α-methylstyrene, α-chlorostyrene, dimethylstyrene, etc. can be used.

As the vinyl cyanide compound, acrylonitrile, methacrylonitrile, etc. are used.

Examples of the methacrylic acid ester compound include methacrylic acid alkyl esters in which the alkyl group has 1 to 8 carbon atoms.

The polymerization ratio of these vinyl compounds and rubber can be selected within an appropriate range depending on the purpose, but usually a rubber content of 5 to 60% by weight is used based on 95% by weight of the vinyl compound.

σ-methylstyrene-acrylonitrile copolymer is 90
10 to 60% by weight of methyl styrene;
A copolymer of 40% acrylonitrile is used.

In molding the composition of the present invention, known stabilizers and lubricants commonly used in processing vinyl chloride resins,
Ultraviolet absorbers, antioxidants, etc. can be added as appropriate, and fillers can also be used if necessary.

In order to fully exhibit the physical properties of the composition, it is desirable to knead it as uniformly as possible, and kneading methods include well-known methods such as roll kneading, Banbury kneading, and extruder kneading, and direct extrusion molding from powder. It is also possible.

The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited thereto.

Example 1 Polyvinyl chloride with an average degree of polymerization of 1.100 (Sumitomo Chemical Co., Ltd., Sumilit ■5x-11), EPDM/acrylonitrile/styrene copolymer (rubber content M52%), thorn-methylstyrene/acrylonitrile copolymer (synthetic Mass ratio 7
o: 30) in the proportions shown in Table 1, add the 5-layer lead stabilizer and 23 parts by weight of TlO, knead for 7 minutes with two rolls at 200°C, and then knead at 205°C for 10 minutes. Compression molding was performed to obtain a sheet for physical property testing.

As is clear from Table 1, the composition of the present invention has greater impact strength, heat deformation resistance, and elongation properties at high temperatures than a vinyl chloride resin or a two-component mixture of a vinyl chloride resin and an impact modifier. It has improved significantly.

Example 2 Table 2 shows the results of measuring the Charpy impact strength of the composition used in Example 1 after weathering.

Claims (1)

[Claims] 100 parts by weight of the resin composition contains (a) 55 to 90 parts by weight of a vinyl chloride resin, (b) 5 to 40 parts by weight of an ethylene-propylene-nonconjugated diene copolymer rubber-based face impact modifier, and (C) A thermoplastic resin composition comprising 5 to 40 parts by weight of an α-methylstyrene-acrylonitrile copolymer.