JP2756612B2 - Thermoplastic resin composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermoplastic rubber-reinforced styrene resin composition having permanent antistatic performance.

[Conventional technology and problems]

ABS resin and HIPS (high impact polystyrene)
Are excellent in moldability, balance between impact strength and rigidity, and excellent appearance of molded products, and are widely used as materials for automobile parts, electric products, office equipment and the like.

However, rubber-reinforced styrenic resins are easily charged like other plastics, and dust and dirt are attracted to the surface of the molded product to impair the appearance of the molded product. In the case of electronic equipment, the problem is that the charged electricity causes damage. was there.

Conventionally, a method of adding an antistatic agent to a rubber-reinforced styrenic resin has been generally used as an antistatic method, but this method has a problem that the durability of the antistatic effect is insufficient.

[Means for solving the problem]

The present inventors have studied a method of imparting permanent antistatic performance to a rubber-reinforced styrene-based resin, and found that a copolymer of ethylene oxide and propylene oxide and an organic sulfonic acid metal salt were added to the rubber-reinforced styrene-based resin. It has been found that the above objects can be achieved by blending at a specific ratio, and the present invention has been achieved.

That is, the present invention relates to a rubber-reinforced styrene resin (A)
80 parts by weight of the copolymer of ethylene oxide and propylene oxide (B) and 3 to 20 parts by weight of the total amount of 100 parts by weight, and 0.1 to 5 parts by weight of the metal salt of dodecylbenzenesulfonic acid (C)
It is a thermoplastic resin composition containing parts by weight.

The rubber-reinforced styrene resin (A) used in the present invention is:
A graft polymer (i) comprising a rubber component and a styrene-based resin component, and generally obtained by polymerizing a styrene-based monomer and another copolymerizable monomer in the presence of the rubber component; A mixture of a graft polymer (i) and a styrene monomer or a (co) polymer obtained by polymerizing a styrene monomer and another copolymerizable monomer, or a rubber component and (Iii) with a (co) polymer of

ABS resin (acrylonitrile-butadiene rubber-styrene copolymer), MBS resin (methyl methacrylate-
Butadiene rubber-styrene copolymer, AES resin (acrylonitrile-ethylene-propylene rubber-styrene copolymer), AAS resin (acrylonitrile-acrylic rubber-styrene copolymer), HIPS (butadiene rubber-styrene copolymer) Those traded under the name of (polymer) are exemplified as the rubber-reinforced styrene resin (A).

As the rubber component, polybutadiene, polyisoprene, butadiene-styrene copolymer, isoprene-styrene copolymer, butadiene-acrylonitrile copolymer, butadiene-isoprene-styrene copolymer, diene rubber such as polychloroprene, ethylene- Examples include ethylene-propylene rubbers such as propylene copolymers and ethylene-propylene-diene copolymers, and acrylic rubbers such as polybutyl acrylate.

In addition, examples of the styrene monomer used in the above-mentioned graft polymer and (co) polymer include styrene, α-methylstyrene, paramethylstyrene, and the like, and one or more kinds can be used. Especially styrene, α-
Methylstyrene is preferred.

Other copolymerizable monomers that can be used together with the styrene monomer include vinyl cyanide compounds such as acrylonitrile and methacrylonitrile, and (meth) acrylate compounds such as methyl methacrylate and methyl acrylate. And maleimide compounds such as N-phenylmaleimide and N-cyclohexylmaleimide, each of which can be used alone or in combination.

Further, from the viewpoint of balance of physical properties of the final composition, in the presence of one or more rubbers (1) selected from the group consisting of diene rubber, ethylene-propylene rubber, and acrylic rubber,
Polymerizing a styrene monomer (2) and one or more other copolymerizable monomers (3) selected from the group consisting of vinyl cyanide compounds, (meth) acrylate compounds, and maleimide compounds; Rubber-reinforced styrene-based resin, which is a mixture of the graft polymer obtained and a copolymer obtained by polymerizing the monomers (2) and (3), is preferable.

The copolymer (B) of ethylene oxide and propylene oxide used in the present invention may be any of a block copolymer, a graft copolymer, a random copolymer or an alternating copolymer, but the antistatic properties of the final composition Desirably, it is a random copolymer from the aspect.

Although the composition ratio of ethylene oxide and propylene oxide is not particularly limited, the molar ratio of ethylene oxide / propylene oxide is preferably 99/1 to 50/50 from the viewpoint of the antistatic property of the final composition and the appearance of the molded article. . If the ratio of propylene oxide is less than 1, the antistatic property is reduced, and if it exceeds 50, flow marks tend to appear on the molded article. More preferably, it is from 97/3 to 70/30.

The average molecular weight of the copolymer (A) is not particularly limited, but is preferably 10,000 to 5,000,000, and more preferably 20,000 to 4,000,000. If the average molecular weight is less than 10,000, the antistatic effect is not sufficient, and the impact strength of the final composition tends to decrease. The average molecular weight is most preferably 100,000 to 3,000,000 in terms of antistatic properties and impact strength.

The composition of the rubber-reinforced styrene resin (A) and the copolymer (B) of ethylene oxide and propylene oxide is 3 to 20 parts by weight of (B) based on 97 to 80 parts by weight of (A). 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 property after washing is inferior. The use amount of this copolymer is preferably 5 to 20 parts by weight, more preferably 7 to 15 parts by weight.

Examples of the metal salt of dodecylbenzenesulfonic acid (C) of the present invention include lithium, potassium and sodium salts of dodecylbenzenesulfonic acid.

The use amount of the metal salt of dodecylbenzenesulfonic acid is 0.1 to 5 parts by weight based on 100 parts by weight of the total amount of the rubber-reinforced styrene resin (A), ethylene oxide and propylene oxide copolymer (B). When the amount of the metal salt of dodecylbenzenesulfonic acid is less than 0.1 part by weight, the antistatic property of the composition is poor. Further, even if the content of the metal salt of dodecylbenzenesulfonic acid exceeds 5 parts by weight, the antistatic property of the composition is not further improved, and on the other hand, the dispersibility is deteriorated, and the appearance is impaired by depositing on the surface of the molded article, Further, the surface is sticky, which is not preferable. The amount of the metal salt of dodecylbenzenesulfonic acid is preferably 0.5 to 3 parts by weight.

The antistatic thermoplastic resin composition of the present invention includes 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], an ultraviolet absorber [for example, pt
-Butylphenyl salicylate, 2,2'-dihydroxy-4-methoxybenzophenone, 2- (2'-hydroxy-4'-n-octoxyphenyl) benzotriazole], a lubricant (for example, paraffin wax, stearic acid, hardened oil, Stearoamide, methylene bis-stearamide, ethylene bis-stearamide, n-butyl stearate, ketone wax, octyl alcohol, lauryl alcohol, hydroxystearic acid triglyceride), flame retardant (e.g., antimony oxide, aluminum hydroxide, zinc borate, Tricresyl phosphate, tris (dichloropropyl) phosphate, chlorinated paraffin, tetrabromobutane, hexabromobenzene, tetrabromobisphenol A], coloring agent [for example, titanium oxide, carbon black] Fillers [such as calcium carbonate, clay, silica, glass fibers, glass beads, carbon fibers], can be added as required pigments.

Further, in the present invention, the use of other antistatic agents is not hindered at all.

The composition of the present invention may further contain other thermoplastic resins such as polymethyl methacrylate, polyvinyl chloride, polyamide, polybutylene terephthalate, polyethylene terephthalate, polyphenylene oxide, and polyoxymethylene, if necessary. it can.

Next, the present invention will be described based on examples, but the present invention is not limited to only these examples.

It should be noted that all parts in the composition are parts by weight.

Examples and Comparative Examples A rubber-reinforced styrene resin, an ethylene oxide-propylene oxide copolymer and a metal salt of dodecylbenzene sulfonic acid were mixed with a vent according to the composition shown in Table 1 to 40.
mm Kneading and pelletizing with a single-screw extruder (set temperature 220 ° C), 3.5 oz horizontal injection molding machine (set temperature 220
° C) to prepare various test pieces.

The polymers and compounds used are as follows. Table 1 shows the physical properties of the obtained composition.

Rubber-reinforced styrene-based resin (A) ABS: Rubber content of a graft polymer obtained by polymerizing styrene and acrylonitrile in the presence of polybutadiene and a copolymer obtained by polymerizing styrene and acrylonitrile 11
% ABS resin AES: AES resin with a rubber content of 17% consisting of a graft polymer obtained by polymerizing styrene and acrylonitrile in the presence of ethylene / propylene / ethylidene norbornene rubber and a copolymer obtained by polymerizing styrene and acrylonitrile Copolymer (B-1-3, X-1-2) B-1: Ethylene oxide (EO) with an average molecular weight of 800,000 *
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 below.

B-2: EO-PO copolymer having an average molecular weight of 1.1 million (molar ratio; EO / PO = 50/50) B-3: EO-PO copolymer having an average molecular weight of 1,000,000 (molar ratio; EO / PO = X-1: EO homopolymer (Molecular weight cannot be measured; it does not dissolve in tetrahydrofuran.) X-2: PO homopolymer having an average molecular weight of 1,000,000 Metal salt of organic sulfonic acid (C) DBS: Dodecyl Sodium benzenesulfonate LAS: Sodium linear alkyl sulfonate (Measurement conditions) (i) Notched Izod impact strength Conforms to ASTM D-256 (1/4 inch thickness) 23 ° C (ii) Flexural modulus ASTM D-790 Compliant 23 ° C (iii) Surface resistance Measured using a flat plate of 90 × 40 × 3 mm under the following conditions. (A) Test specimens were tested at 23 ° C and 55% relative humidity for 24 hours.
Measure after adjusting the time condition (b) After thoroughly washing the surface of the test piece with pure water,
Surface resistance is measured after conditioning for 24 hours at 23 ° C and 55% relative humidity. Surface resistance is measured by a high resistance meter SM manufactured by Toa Denpa Kogyo.
Performed using -10E.

(Iv) Appearance A 50 mm x 50 mm x 3 mm plate is molded and visually checked for flow marks and coloring. The appearance of the flow mark and the degree of coloring are “good (○)”,
"Slightly good (△)" and "poor (x)"

The rubber-reinforced styrene-based resin composition of the present invention shows good antistatic properties even after washing with water and is excellent in durability, as compared with the composition (Comparative Example 2) to which an ordinary antistatic agent is added. Also, mechanical strength such as Izod impact strength and flexural modulus is good. On the other hand, when the metal sulfonate (C) was not added, the antistatic property was reduced (Comparative Example 3), and when the added amount exceeded 5 parts (Comparative Example 4), the surface appearance was significantly reduced due to discoloration. But not preferred. On the other hand, when the amount of the ethylene oxide-propylene oxide copolymer (B) is less than 3 parts (Comparative Example 5), the antistatic property after washing is reduced, and
If the amount exceeds 20 parts (Comparative Example 6), the flow mark becomes conspicuous, the appearance is impaired, and the flexural modulus decreases. When the homopolymer of ethylene oxide is used (Comparative Example 7), the antistatic property is reduced. When the homopolymer of propylene oxide is used (Comparative Examples 8 and 9), the flow mark of the molded product is noticeable. It is not preferable because the appearance is impaired.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ identification code FI C08L 71:02) (58) Investigated field (Int.Cl. ⁶ , DB name) C08L 55/02 C08L 51/04 C08K 5 / 42 C08L 71/02

Claims (1)

(57) [Claims] A metal dodecylbenzenesulfonate based on 100 parts by weight of a total of 97 to 80 parts by weight of a rubber-reinforced styrene resin (A) and 3 to 20 parts by weight of a copolymer of ethylene oxide and propylene oxide (B). A thermoplastic resin composition comprising 0.1 to 5 parts by weight of a salt (C).