JPH04198250A - Thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide a permanent antistatic property by compounding a rubber- reinforced styrene resin, an ethylene oxide-propylene oxide copolymer, and a metal salt of an org. sulfonic acid. CONSTITUTION:100 pts.wt. the sum of 97-80 pts.wt. rubber-reinforced styrene resin (e.g. ABS resin) and 3-20 pts.wt. copolymer comprising 99-50mol% ethylene oxide and 1-50mol% propylene oxide and having an average mol.wt. of 10000-5000000 is compounded with 0.1-5 pts.wt. metal salt of an org. sulfonic acid (e.g. sodium dodecylbenzenesulfonate).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to thermoplastic rubber reinforced styrenic resin compositions having permanent antistatic properties.

[Conventional technology and problems]

Rubber-reinforced styrene resins such as ABS resin and I (IPS (high impact polystyrene)) have excellent moldability, balance between impact strength and rigidity, and appearance of molded products, and are widely used as materials for automobile parts, electrical products, office equipment, etc. It's being used.

However, like other plastics, rubber-reinforced styrene resin is easily charged with electricity, and dirt and dust can be attracted to the surface of the molded product, damaging the appearance of the molded product, and in the case of electronic devices, the charged electricity can cause problems. was there.

Conventionally, a method of adding an antistatic agent to a rubber-reinforced styrene resin has been commonly used as an antistatic method, but this method has a problem in that the antistatic effect is insufficiently durable.

[Means for solving problems]

The present inventors investigated methods for imparting permanent antistatic properties to rubber-reinforced styrenic resins, and found that a copolymer of ethylene oxide and propylene oxide and an organic sulfonic acid metal salt were added to rubber-reinforced styrenic resins. It has been discovered that the above object can be achieved by blending in a specific ratio, and the present invention has been achieved.

That is, the present invention provides rubber-reinforced styrenic resin (A) 97-
A total of 100 parts by weight of 80 parts by weight and 3 to 20 parts by weight of a copolymer of ethylene oxide and propylene oxide (B) is mixed with 0.1 to 5 parts by weight of an organic sulfonic acid metal salt (C). It is a thermoplastic resin composition.

The rubber reinforced styrenic resin (A) used in the present invention is composed of a rubber component and a styrene resin component, and is generally composed of a styrene monomer and other copolymerizable monomers in the presence of the rubber component. A graft polymer formed by polymerizing monomers (i
), a mixture (i) of the graft polymer (i) and a styrenic monomer or a (co)polymer obtained by polymerizing a styrene monomer and another copolymerizable monomer, or a rubber component. It consists of a mixture (ii) with the above-mentioned (co)polymer.

ABS resin (acrylonitrile-butadiene rubber-styrene copolymer), MBS resin (methyl methacrylate-butadiene rubber-styrene copolymer), ABS resin (acrylonitrile-ethylene/propylene rubber-styrene copolymer), AAS resin (acrylonitrile-acrylic rubber-styrene copolymer), H-KPS (butadiene rubber-styrene copolymer), etc. are exemplified as the rubber reinforcing layer styrene resin (A). .

Rubber components include polybutadiene, polyisofrene,
Ethylene-propylene rubbers such as butadiene-styrene copolymer, isoprene-styrene copolymer, butadiene-acrylogom, ethylene-propylene copolymer, ethylene-propylene-diene copolymer, acrylic rubber such as polybutyl acrylate, etc. can be mentioned.

Further, examples of the styrene monomer used in the above-mentioned graft polymer and (co)polymer include styrene, α-methylstyrene, paramethylstyrene, etc., and one or more types can be used. Particularly preferred are styrene and a-methylstyrene.

Other copolymerizable monomers that can be used with the styrenic monomer include vinyl cyanide compounds such as acrylonitrile and methacrylate; (meth)acrylic acid ester compounds such as methyl methacrylate and methyl acrylate; Examples include maleimide compounds such as N-phenylmaleimide and N-cyclohexylmaleimide, and one or more types of each can be used.

Furthermore, in view of the physical property balance of the final composition, a styrene monomer (2) is added in the presence of one or more rubbers (1) selected from the group consisting of diene rubber, ethylene-propylene rubber, and acrylic rubber. and a graft polymer obtained by polymerizing one or more other copolymerizable monomers (8) selected from the group consisting of vinyl cyanide compounds, (meth)acrylic acid ester compounds, and maleimide compounds, and the above monomers. Body (2
) and a copolymer obtained by polymerizing (3), a rubber-reinforced styrenic resin is preferred.

The copolymer (B) of ethylene oxide and propylene oxide used in the present invention may be a block copolymer, a graft copolymer, a random copolymer, or an alternating copolymer. A random copolymer is preferable.

Although there is no particular restriction on the composition ratio of ethylene oxide and propylene oxide, it is preferable that the molar ratio of ethylene oxide/propylene oxide is 99/l to 50,150 in terms of the antistatic properties of the final composition and the appearance of the molded product. If the ratio of propylene oxide is less than 1, the antistatic property will be lowered to 1/30.

The average molecular weight of the copolymer (A) is also not particularly limited, but is preferably from 10,000 to 5,000,000, more preferably from 20,000 to 40,000,000. If the average molecular weight is less than 10,000, the antistatic effect will not be sufficient and the impact strength of the final composition will tend to decrease.

The average molecular weight is 100,000 or more in terms of antistatic properties and impact strength.
3 million is most preferred.

The blending composition of the rubber-reinforced styrene resin (A) and the copolymer of ethylene oxide and propylene oxide (B) is (
A) 97 to 80 parts by weight, and (B) 3 to 20 parts by weight. However, the total amount of (A) and (B) is 100 parts by weight. If the amount of the copolymer is less than 3 parts by weight, the antistatic properties after washing will be poor, and if it exceeds 20 parts by weight, flow marks will become noticeable and the appearance will be impaired, and the flexural modulus will decrease, which is not preferable. The amount of this copolymer used is preferably 5 to 20
Parts by weight, more preferably 7 to 15 parts by weight.

Examples of the organic sulfonic acid metal salt (C) of the present invention include nuclear-substituted or non-nuclear-substituted benzenesulfonic acid metal salts, alkyl sulfonic acid metal salts, etc., and one or more types can be used. Preferred are alkali metal salts of nuclear-substituted benzenesulfonic acids, such as L i , K , and N a salts of dodecylbenzenesulfonic acid.

The amount of the organic sulfonic acid metal salt used is 0.1 to 5 parts by weight per 100 parts by weight of rubber reinforcement. If the amount of the organic sulfonic acid metal salt used is less than 0.1 part by weight, the antistatic properties of the composition will be poor. Furthermore, even if the amount of the organic sulfonic acid metal salt exceeds 5 parts by weight, the antistatic properties of the composition will not improve any further;
On the other hand, it is undesirable because the dispersibility deteriorates and it precipitates on the surface of the molded product, impairing its appearance and making the surface sticky.

The amount of organic sulfonic acid metal salt used is preferably 0.5 to 3
Parts by weight.

The antistatic thermoplastic resin composition of the present invention contains an antioxidant [
For example, 2,6-di-t-butyl-4-methylphenol, 2-(1-methylcyclohexyl')-4,6-dimethylphenol, 2,2-methylene-bis-(4-ethyl-6-t- methylphenol), 4,4'-thiobis-(6-t-butyl-3-methylphenol), dilaurylthiodipropionate, tris(di-nonylphenyl)phosphite, wax], ultraviolet absorbers [e.g. p-t-butylphenylsalicyle), 2,2'-dihydroxy-4-methoxybenzophenone, 2-(2'
-hydroxy-4'-n-octoxyphenyl)benzotriazole], lubricants [e.g. paraffin wax, stearic acid, hydrogenated oil, stearamide, methylene bis stearamide, ethylene bis stearamide, n-butyl stearate, ketone wax , octyl alcohol, lauryl alcohol, hydroxystearic acid triglyceride], flame retardants [e.g., antimony oxide, fluminiram hydroxide, zinc oxalate, tricresyl phosphate, tris(dichloropropyl) phosphate, chlorinated paraffin, tetrabromobutane, Hexabromobenzene, tetrabromobisphenol A], colorants [e.g. titanium oxide, carbon black], fillers [e.g. calcium carbonate, clay, silica, glass fiber, glass spheres, carbon fiber], pigments, etc. are added as necessary. I can do that.

Further, in the present invention, there is no preclude the use of other antistatic agents in combination.

Furthermore, other thermoplastic resins such as polymethyl methacrylate, polyvinyl chloride, polyamide, polybutylene terephthalate, polyethylene terephthalate, polyphenylene oxide, polyoxymethylene, etc. may be mixed into the composition of the present invention, if necessary. can.

Next, the present invention will be explained based on Examples, but the present invention is not limited to these Examples.

It should be noted that all parts in the formulations represent parts by weight.

Examples and Comparative Examples Rubber-reinforced styrenic resin with ethylene oxide 40
After mixing and pelletizing using a single-screw extruder (temperature set at 220"C), various test pieces were prepared using a 3.5 oz horizontal injection molding machine (temperature set at 220"C).

Rubber reinforced styrenic resin (A) ABS: Rubber content 11 consisting of a graft polymer formed by polymerizing styrene and acrylonitrile in the presence of polybutadiene and a copolymer formed by polymerizing styrene and acrylonitrile.
% ABS resin AES: AES resin with a rubber content of 17%, consisting of a graft polymer formed by polymerizing styrene and acrylonitrile in the presence of ethylene propylene ethylidene norbornene rubber and a copolymer formed by polymerizing styrene and acrylonitrile. Copolymer (B-1 to 3, X-1 to 2) B-1: Ethylene oxide (E
O)-propylene oxide (PO) copolymer (molar ratio; EO/PO=75/25') * Average molecular weight in terms of polystyrene, measured using GPC at 40°C in tetrahydrofuran. same as below.

B-2: EO-PO copolymer with an average molecular weight of 1.1 million (molar ratio: EO/PO=50150) B-3, EO-PO copolymer with an average molecular weight of 100,000-100,000; EO/PO =25/75) not dissolved.

) X-2: PO homopolymer organic sulfonic acid metal salt with average molecular weight of 1 million (C) DBS sodium nidodecylbenzenesulfonate LAs
: Linear sodium alkyl sulfonate (measurement conditions) (i) Notched Izot impact strength A, STM
Based on D-256 (1/4 inch thickness) 23°C (11) Flexural modulus Based on ASTM D-790 23°C (iii) Measured under the following conditions using a flat plate with surface resistance 90X4QX3- ) The specimen was heated at 23°C and 155% relative humidity for 24 hours.
After thoroughly washing the surface of the test piece with pure water, 23°C
The surface resistance was measured after conditioning for 24 hours under the condition of 155% relative humidity using a high resistance meter 5M-10E manufactured by Toa Denpa Kogyo ■.

(iv) A plate with an external appearance of 50 + w x 50 tax x 8 m was molded and visually checked for flow marks and coloring. The degree of conspicuousness of the flow mark and the degree of coloring were each expressed in three levels: "Good (○)", 1 "Slightly good" (△), and 1 "Poor"(#).

The rubber-reinforced styrenic resin composition of the present invention exhibits better antistatic properties even after washing with water, and its durability is excellent, compared to a composition containing an ordinary antistatic agent (Comparative Example 2). There is.

In addition, mechanical strengths such as Izot impact strength and flexural modulus are also good. On the other hand, when sulfonic acid metal salt (C) ■footwear layer- is not added, the antistatic property is decreased (Comparative Example 3), and when the amount added exceeds 5 parts (Comparative Example 4), the surface appearance is changed due to discoloration. This is a significant decrease and is not desirable. Furthermore, the flow marks of ethylene oxide-propylene oxide copolymer (B) Example 6) are noticeable and impair the appearance, and the flexural modulus is lowered. 1 is not preferable because flow marks on the molded product impair the appearance of the medachi.

Claims (1)

[Claims] 97 to 80 parts by weight of rubber-reinforced styrene resin (A) and a copolymer of ethylene oxide and propylene oxide (
B) A thermoplastic resin composition containing 0.1 to 5 parts by weight of an organic sulfonic acid metal salt (C) to 100 parts by weight in total of 3 to 20 parts by weight.