JPH0940841A - Sliding resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a sliding resin composition generating slight creak sound by a contacting, having excellent mechanical strength, processability and a surface appearance, and useful for automobile interior members, etc., by blending a rubber-reinforcing styrene-based resin and a specific silicone rubber-grafted polymer in a specific ratio. SOLUTION: This sliding resin composition is composed of (A) 100 pts.wt. of a rubber-reinforcing styrene-based resin such as polybutadiene and (B) 0.2-50 pts.wt. of a silicone rubber-grafted polymer graft-polymerized with 0.3-50 pts.wt. of a silicone rubber based on 100 pts.wt. of a polymer comprising an aromatic vinyl compound such as styrene, or a copolymer of the aromatic vinyl compound and another compound copolymerizable with the compound, e.g. an ethylenic unsaturated compound such as acrylonitrile.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a slidable resin composition. More specifically, the present invention relates to a slidable resin composition obtained by blending a rubber-reinforced styrene-based resin with a specific graft polymer, which has an excellent surface appearance and has less squeaking noise due to contact.

[0002]

2. Description of the Related Art Rubber-reinforced styrene resins represented by ABS resin, AES resin and AAS resin are excellent in mechanical properties such as impact resistance and rigidity and workability, and have excellent surface appearance such as surface gloss. It is used in a wide range of applications such as vehicles, light electric power, and office equipment. However, rubber reinforced styrenic resin can be used for mechanical properties where abrasion resistance is required and for applications where squeaking noise generated by contact with other resin parts is a problem. It is currently rarely used because it is inferior to

A method of generally adding polyorganosiloxane to impart slidability (Japanese Patent Publication No. 217254/1985).
Japanese Patent Publication No. 6-23291) is proposed, but the polyorganosiloxane to be added is liquid at 25 ° C., and the added amount is contained in a small amount in terms of silicon content, and the slidability effect is obtained. The expression is insufficient. Further, the addition of a small amount of polyorganosiloxane does not show any effect as a countermeasure against the squeaking noise generated by the contact between resin parts. on the other hand,
If the amount of polyorganosiloxane added is increased, fatal problems such as flow marks, silver, and layer delamination occur, making it difficult to use as a resin product. In addition, a method of adding polyorganosiloxane to a rubber-reinforced styrene resin to improve impact resistance and workability (Japanese Patent Publication No. 6-2
3294) have been proposed, but none of them are intended for slidability, and such effects cannot be expected. As described above, a material having improved slidability by utilizing the original characteristics of the rubber-reinforced styrene resin has not been developed.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The inventors of the present invention have earnestly studied a sliding rubber-reinforced styrene resin having an excellent surface appearance and less squeaking noise. By adding a specific amount of a silicone gum graft polymer obtained by graft polymerization to a rubber-reinforced styrene-based resin, it was found that a sliding resin composition having an excellent surface appearance and less squeaking sound can be obtained. The invention was reached.

[0005]

[Means for Solving the Problems] That is, the present invention relates to 100 parts by weight of a rubber-reinforced styrenic resin (a), an aromatic vinyl compound, or an aromatic vinyl compound and another ethylenically unsaturated copolymerizable therewith. Polymer composed of compound 10
Silicon gum graft polymer (b) 0.2-by graft polymerization of 0.1 to 30 parts by weight of silicon gum per 0 part by weight
It is intended to provide a slidable resin composition containing 50 parts by weight and having an excellent surface appearance and less squeaking noise. Hereinafter, the sliding resin composition of the present invention will be described in detail.

The rubber-reinforced styrene resin in the present invention is a graft obtained by polymerizing an aromatic vinyl compound or an aromatic vinyl compound and another ethylenically unsaturated compound copolymerizable therewith in the presence of rubber. A polymer, or a mixture of the graft polymer and an aromatic vinyl compound or an aromatic vinyl polymer obtained by copolymerizing an aromatic vinyl compound or another ethylenically unsaturated compound copolymerizable with the aromatic vinyl compound.

As the rubber, butadiene rubber (1) such as polybutadiene, butadiene-styrene copolymer, butadiene-acrylonitrile copolymer, etc., binary copolymer (EPR) consisting of ethylene and propylene or butene, ethylene, propylene. Alternatively, an ethylene-α olefin rubber (2) such as a terpolymer (EPDM) composed of butene and a non-conjugated diene (ethylidene norbornene, dicyclopentadiene, etc.), and an alkyl group having 1 carbon atom
~ 16 alkyl acrylates (methyl acrylate,
Acrylic rubber obtained by copolymerizing one or two or more of (ethyl acrylate, 2-ethylhexyl acrylate, butyl acrylate, etc.), and further, one or more of other copolymerizable monomers as necessary. (3),
Examples thereof include ethylene-vinyl acetate copolymer (4) and chlorinated polyethylene (5), which may be used alone or in combination of two or more.

As the aromatic vinyl compound, styrene,
α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, t-butylstyrene,
Examples include α-methylvinyltoluene, dimethylstyrene, chlorostyrene, dichlorostyrene, bromstyrene, dibromostyrene, vinylnaphthalene, and the like, or one or more of them can be used. Particularly, styrene and α-methylstyrene are preferable.

Other copolymerizable ethylenically unsaturated compounds which can be used together with the aromatic vinyl compound include vinyl cyanide compounds (1) such as acrylonylyl, methacrylonitrile, ethacrylonitrile and fumaronitrile, methyl acrylate, Ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate,
Unsaturated carboxylic acid alkyl ester compound (2) such as methyl methacrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, 2-ethylhexyl methacrylate, maleimide, N-phenylmaleimide, N-methylmaleimide, N-cyclohexylmaleimide And the like, and unsaturated amide compounds (4) such as acrylamide and methacrylamide, etc., and one kind or two or more kinds can be used. Especially acrylonitrile, methyl acrylate, methyl methacrylate, N-
Phenylmaleimide is preferred.

Specific examples of the rubber-reinforced styrene resin include the following resins. However, it is not limited to the following resins. Butadiene rubber-reinforced acrylonitrile-styrene polymer (ABS), butadiene rubber-reinforced methyl methacrylate-styrene polymer (MBS), ethylene-propylene rubber-reinforced acrylonitrile-styrene polymer (AEA), acrylic rubber-reinforced acrylonitrile-styrene polymer Combined (ASA), chlorinated polyethylene reinforced acrylonitrile-styrene polymer (ACS),
And one or more of those polymers, acrylonitrile-styrene copolymer, α-methylstyrene-acrylonitrile copolymer, α-methylstyrene-acrylonitrile-methylmethacrylate copolymer, maleic anhydride-styrene copolymer, N -Phenylmaleimide-styrene copolymer, α-methylstyrene-N-phenylmaleimide-acrylonitrile copolymer, N-phenylmaleimide-methylmethacrylate copolymer or mixture with N-phenylmaleimide-methylmethacrylate-styrene copolymer Is.

The above-mentioned various polymers and copolymers can be produced by emulsion polymerization method, suspension polymerization method, solution polymerization method,
A bulk polymerization method or a method combining these methods may be mentioned.

Next, the silicone gum graft polymer used in the present invention means an aromatic vinyl compound, or an aromatic vinyl compound comprising an aromatic vinyl compound and another ethylenically unsaturated compound copolymerizable therewith. It is a graft polymer obtained by graft polymerizing 0.1 to 30 parts by weight of silicon gum per 100 parts by weight.

Examples of the aromatic vinyl compound constituting the aromatic vinyl polymer and the other copolymerizable ethylenically unsaturated compound include those exemplified in the above section of the rubber-reinforced styrene resin. Styrene is preferable as the aromatic vinyl compound, and acrylonitrile, methacrylate, methyl methacrylate, glycidyl methacrylate and the like are preferable as the other copolymerizable ethylenically unsaturated compound. Specifically, polystyrene, acrylonitrile-styrene copolymer, α-methylstyrene-acrylonitrile copolymer, α-methylstyrene-acrylonitrile-methyl methacrylate copolymer, glycidyl methacrylate-acrylonitrile-styrene copolymer, glycidyl methacrylate- N-phenylmaleimide-styrene copolymer, maleic anhydride-
Styrene copolymer, N-phenylmaleimide-styrene copolymer, α-methylstyrene-N-phenylmaleimide-acrylonitrile copolymer, N-phenylmaleimide-methylmethacrylate copolymer or N-phenylmaleimide-methylmethacrylate-styrene Copolymers and mixtures thereof.

The composition, constitution and production method of the aromatic vinyl polymer are not particularly limited, but the aromatic vinyl compound 3
0-100% by weight, other copolymerizable ethylenically unsaturated compound 0-70% by weight, especially aromatic vinyl compound 50-
70% by weight and 30 to 50% by weight of another copolymerizable ethylenically unsaturated compound are preferable. The intrinsic viscosity (dimethylformamide, 30 ° C) of the aromatic vinyl polymer is not particularly limited, but is preferably 0.35 to 1.3. If it is less than 0.35, mechanical properties such as impact strength tend to be inferior, while if it exceeds 1.3, the processability of the composition is inferior and it becomes difficult to obtain a good surface appearance.

As the silicone gum, 1) a high molecular weight dimethylpolysiloxane, 2) a high molecular weight dimethylpolysiloxane having a functional group such as an amino group or an epoxy group in the side chain, or 3). A terminal group also having a functional group such as an amino group and an epoxy group, and further,
4) Silanol having a hydroxyl group (R-Si-OH) or 5) Siloxane bound to oxygen (R-Si-)
O) and the like.

Silicon gum can be obtained by dehydrating dimethylsilanol or the like by heating to obtain a linear polymer by condensation fusion, or by polymerizing octamethylcyclotetrasiloxane or octaethylcyclotetrasiloxane in the presence of a peroxide. It can be produced by a method of polymerizing dimethyl silicon, methylphenyl silicon, methyl vinyl silicon or the like to obtain a highly viscous material.

Silicon gum is a rubber-like ultra-high viscosity material. 5000-100 like used as silicone oil
It is not a polymer having a low viscosity of 00 centistokes, that is, a low degree of polymerization. The viscosity of the silicone gum is not particularly limited, but is preferably 500,000 centistokes or more at 23 ° C., and particularly preferably 1 million or more. If it is less than 500,000 centistokes, the slidability improvement and the squeak noise reduction effect are poor. The graft ratio to the aromatic vinyl polymer is insufficient, and a composition having good physical properties and appearance cannot be obtained. Furthermore, in the case of a polymer having a crosslinked structure such as silicone rubber and having a remarkable rubber elasticity or an ultrahigh molecular weight polymer which is difficult to melt, the graft ratio to an aromatic vinyl polymer is insufficient, and the obtained graft polymer Since the compatibility of the rubber-reinforced styrenic resin is poor, a composition having good physical properties and appearance cannot be obtained.

In the present invention, it is important that the silicone gum is graft-polymerized with the aromatic vinyl polymer. Even if the silicone gum is not graft-polymerized and mixed alone into the rubber-reinforced styrene resin, the dispersion is poor and streaky streaks are observed in the molded product, and a good surface appearance cannot be obtained. During the polymerization, the above-mentioned side chain or the functional group at the terminal works effectively, and the aromatic vinyl compound-based polymer is surely graft-polymerized. As a method of graft-polymerizing a silicone gum onto an aromatic vinyl polymer, for example,
A silicone gum graft polymer can be obtained by introducing the aromatic vinyl polymer into the hopper of the extruder, and then introducing the silicone gum together with the polymerization initiator in the molten state from the middle.

The amount of silicone gum in the silicone gum graft polymer is 100 parts by weight of the aromatic vinyl polymer,
It is 0.3 to 50 parts by weight, preferably 1.0 to 30 parts by weight. If the amount of silicone gum is less than 0.3 parts by weight, the effect of improving the slidability is not exhibited, and if it exceeds 50 parts by weight, it is difficult to mix with the rubber-reinforced styrene resin, and the slidability of the obtained product is good. However, the surface appearance is remarkably inferior, flow marks and layer peeling occur, and a product that can withstand practical use cannot be obtained.

The amount of silicone gum graft polymer added is
0.2 to 100 parts by weight of rubber-reinforced styrene resin
It is 50 parts by weight, preferably 1.0 to 40 parts by weight. If the addition amount of the silicone gum graft body is less than 0.2 parts by weight, there is no effect in improving slidability and squeaking noise,
Further, if it exceeds 50 parts by weight, it is difficult to mix it with the rubber-reinforced styrene resin, and if the obtained mixture is molded, silver and flow marks are generated, and a product having a good appearance cannot be obtained.

The rubber-reinforced styrenic resin and the silicone gum graft are mixed with a Banbury mixer, a kneader or a melt kneader such as a single-screw or twin-screw extruder,
A homogeneous composition can be obtained.

The composition of the present invention may contain antioxidants, heat stabilizers, light stabilizers, lubricants, plasticizers, antistatic agents, inorganic and organic colorants, foaming agents, inorganic and Organic colorants, foaming agents, inorganic and organic fillers and the like can be added.

Hereinafter, the composition of the present invention will be described in more detail by way of examples, but the present invention is not limited thereto.

Reference Example 1 Silicone gum (viscosity at 23 ° C. is 1 million centistokes polydimethylsiloxane)
And a glycidyl methacrylate-acrylonitrile-styrene copolymer (5% by weight of glycidyl methacrylate, 65% by weight of styrene, 30% by weight of acrylonitrile polymerized by an emulsion polymerization, an intrinsic viscosity of 0.55) are reacted and kneaded by using a twin-screw extruder. Let By changing the compounding ratio of the silicone gum and the copolymer, three kinds of silicone gum graft polymers having different composition ratios were obtained. Graft A: 100 parts by weight of copolymer, 30 parts by weight of polydimethylsiloxane Graft Y: 100 parts by weight of copolymer, 60 parts by weight of polydimethylsiloxane Graft Z: 100 parts by weight of copolymer, 0.1 part by weight of polydimethylsiloxane

[Reference Example 2] Silicon gum (raw rubber of methyl vinyl silicon having a viscosity at 23 ° C. of 1 million centistokes or more) and acrylonitrile-styrene copolymer (70% by weight of styrene, 30% by weight of acrylonitrile) were subjected to a bulk polymerization method. The polymerized intrinsic viscosity 0.58) and a small amount of peroxide are reacted and kneaded by using a twin-screw extruder to graft 35 parts by weight of silicone gum per 100 parts by weight of the copolymer. Graft B) was obtained.

Examples and Comparative Examples Silicon gum graft polymers (A, Y, X, B) obtained in Reference Examples 1 and 2, the silicone gum or silicone oil used in Reference Examples 1 and 2 (23 ° C., 6000 centistokes, ABS resin (polybutadiene 40 wt%,
40% by weight of a graft polymer composed of 45% by weight of styrene and 15% by weight of acrylonitrile, and 73% by weight of styrene,
Various compositions were obtained by melt-kneading with a mixture of 60% by weight of a copolymer consisting of 27% by weight of acrylonitrile). The blended composition and the performance of the obtained composition are shown in Tables 1 and 2. The evaluation method is as follows.

Impact resistance: According to ASTM D-256.
23 ° C, 4/1 inch thick, notched Izod impact strength. "Kg / cm / cm"

Workability: According to ASTM D-1238.
220 ° C, 10 Kg. "G / 10 minutes"

Sliding property: A 90 × 90 × 3 mm test piece was molded from the composition. A steel ball with a diameter of 11 mm is placed at a point 41 mm from the center of the molded product, and a wear test (72 rotations / minute, 70 minutes) is performed with a load of 200 g. Measures the wear amount "mg", flaw depth "μ", and width "μ" after the wear test.

Squeaking sound: 150 × 120 × 3 from the composition
mm test piece was molded, and the side surface (30 × 50 mm) of the soft vinyl chloride molded product was rubbed by hand, and the presence or absence of a squeaking sound generated at that time was evaluated. "Yes / No"

Appearance: A 150 × 120 three-step thickness (3, 2, 1 mm) test piece was molded from the composition, and the surface of the molded product was visually observed to evaluate the presence or absence of flow marks. "No-good / Yes-bad"

[0032]

[Table 1]

[0033]

[Table 2]

[0034]

The composition of the present invention has not only general physical properties such as mechanical strength and workability but also excellent surface appearance and slidability, and squeaks when contacted with other parts such as vinyl chloride. It is extremely useful as a material for automobile interior parts and a material for office machine internal parts because it does not generate.

Claims (1)

[Claims] 1. Silicon per 100 parts by weight of a polymer comprising an aromatic vinyl compound, or an aromatic vinyl compound and another ethylenically unsaturated compound copolymerizable therewith, in 100 parts by weight of a rubber-reinforced styrene resin (a). Gum 0.3-50
A sliding resin composition comprising 0.2 to 50 parts by weight of a silicone gum graft polymer (b) obtained by graft-polymerizing parts by weight.