JP2016098236A - Ethylene-glycidyl methacrylate copolymer resin composition, ethylene-glycidyl methacrylate copolymer/terminal carboxylic acid modified styrene copolymer composition, graft copolymer, and polyacetal resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for improving slidability of a polyacetal resin while maintaining its mechanical properties.SOLUTION: An ethylene-glycidyl methacrylate copolymer resin composition comprises (A) an ethylene-glycidyl methacrylate copolymer, and (B) a vinyl monomer composition. The (B) vinyl monomer composition is impregnated into the (A) ethylene-glycidyl methacrylate copolymer. The (B) vinyl monomer composition comprises (b-1) a vinyl monomer comprising styrene, (b-3) a polymerization initiator, and (b-4) 3-mercaptopropionic acid.SELECTED DRAWING: None

Description

  The present invention relates to an ethylene-glycidyl methacrylate copolymer resin composition, an ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified styrene copolymer composition, a graft copolymer, and a polyacetal resin composition.

  Polyacetal resin is excellent in slidability in addition to mechanical properties, electrical properties, moldability, and dimensional accuracy of molded products. For this reason, polyacetal resin is used in a wide field as sliding members such as bearings and gears.

  However, in recent years, with the development of the above fields, higher demands have been made on sliding members. In particular, the sliding member is required to further improve slidability such as a friction coefficient, a wear amount, a sliding sound (squeak noise), and the like.

  Techniques for improving the sliding characteristics of polyacetal resin are disclosed in Patent Documents 1 and 2. In the techniques described in Patent Documents 1 and 2, the sliding property of the polyacetal resin is improved by mixing an additive with the polyacetal resin.

  In the technique described in Patent Document 1, a polyolefin copolymer and a branched ester oil are used as additives. In the technique described in Patent Document 2, polyether ester amide resin, modified vinyl compound polymer, polyvalent carbodiimide, and polyvalent epoxy compound are used as additives.

JP 07-133403 A JP 2003-192871 A

  However, the polyacetal resin composition described in Patent Document 1 has a large amount of wear in a sliding test, and sufficient sliding properties cannot be obtained. Moreover, in the polyacetal resin composition described in Patent Document 2, although sufficient slidability is obtained in the sliding test, a decrease in mechanical properties is observed.

  In view of the circumstances as described above, an object of the present invention is to provide a technique for improving slidability while maintaining mechanical properties of a polyacetal resin.

In order to achieve the above object, an ethylene-glycidyl methacrylate copolymer resin composition according to an embodiment of the present invention includes (A) an ethylene-glycidyl methacrylate copolymer, (B) a vinyl monomer composition, and , Containing.
The (B) vinyl monomer composition is impregnated with the (A) ethylene-glycidyl methacrylate copolymer.
The (B) vinyl monomer composition includes (b-1) a vinyl monomer containing styrene, (b-3) a polymerization initiator, and (b-4) 3-mercaptopropionic acid. .

  By adding the graft copolymer obtained from the ethylene-glycidyl methacrylate copolymer resin composition having this configuration to the polyacetal resin, a polyacetal resin composition having excellent mechanical properties and slidability can be obtained.

The (B) vinyl monomer composition may further contain (b-2) acrylonitrile.
According to this configuration, the compatibility of the obtained graft copolymer with the polyacetal resin can be improved. Thereby, the polyacetal resin composition excellent in slidability is obtained.

When the total of the content of the (A) ethylene-glycidyl methacrylate copolymer and the content of the (B) vinyl monomer composition is 100 parts by weight,
The content of the (A) ethylene-glycidyl methacrylate copolymer may be 50 to 90 parts by weight, and the content of the (B) vinyl monomer composition may be 10 to 50 parts by weight.

  By using the ethylene-glycidyl methacrylate copolymer resin composition having this configuration, a polyacetal resin composition further excellent in mechanical properties and sliding properties can be obtained.

The (A) ethylene-glycidyl methacrylate copolymer may contain 2 to 20% by weight of glycidyl methacrylate.
By using the ethylene-glycidyl methacrylate copolymer resin composition having this configuration, a polyacetal resin composition having further excellent slidability can be obtained.

  The ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified styrene copolymer composition according to one embodiment of the present invention is the above-mentioned (B) vinyl monomer impregnated in the ethylene-glycidyl methacrylate copolymer resin composition. It is obtained by polymerizing the body composition.

  By adding a graft copolymer obtained from the ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified styrene copolymer composition of this configuration to the polyacetal resin, a polyacetal resin having excellent mechanical properties and sliding properties A composition is obtained.

The graft copolymer according to one embodiment of the present invention is obtained by melt-kneading the ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified styrene copolymer composition.
The graft copolymer has a main chain composed of the (A) ethylene-glycidyl methacrylate copolymer and a side chain composed of the vinyl copolymer obtained by polymerizing the vinyl monomer composition (B). .

  By adding the graft copolymer having this configuration to the polyacetal resin, a polyacetal resin composition having excellent mechanical properties and sliding properties can be obtained.

The polyacetal resin composition which concerns on one form of this invention contains (X) polyacetal resin and the said graft copolymer ((Y) graft copolymer).
When the content of the (X) polyacetal resin is 100 parts by weight, the content of the (Y) graft copolymer is 3 to 20 parts by weight.

  According to this structure, the polyacetal resin composition excellent in mechanical properties and slidability can be provided.

The polyacetal resin composition may further contain (Z) a polyvalent carboxylic acid.
When the content of the (X) polyacetal resin is 100 parts by weight, the content of the (Z) polyvalent carboxylic acid is 0.1 to 1 part by weight.

  According to this structure, the polyacetal resin composition excellent in slidability can be provided.

  A technique for improving the slidability while maintaining the mechanical properties of the polyacetal resin can be provided.

  Hereinafter, an embodiment of the present invention will be described.

<Overview>
In this embodiment, the (Y) graft copolymer comprising a specific main chain and a side chain and further selectively crosslinking the main chain by a ring-opening reaction of an epoxy group of the main chain is converted into (X) a polyacetal resin. By blending, a polyacetal resin composition in which the (Y) graft copolymer is well dispersed in the (X) polyacetal resin is produced.

  In the polyacetal resin composition according to the present embodiment, the excellent mechanical properties inherent in the polyacetal resin are maintained, and excellent slidability is obtained regardless of the type of the counterpart material and the magnitude of the load. This polyacetal resin composition can be used in a wide range of fields such as electrical parts, electronic parts, machine parts, precision equipment parts, and automobile parts.

  The (Y) graft copolymer according to this embodiment is obtained by melt-kneading an ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified styrene copolymer composition. Further, the ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified styrene copolymer composition polymerizes the vinyl monomer composition (B) impregnated in the ethylene-glycidyl methacrylate copolymer resin composition. Can be obtained. Hereafter, each said composition is demonstrated.

<Ethylene-glycidyl methacrylate copolymer resin composition>
The ethylene-glycidyl methacrylate copolymer resin composition according to this embodiment contains (A) an ethylene-glycidyl methacrylate copolymer (EGMA) and (B) a vinyl monomer composition. (B) The vinyl monomer composition is impregnated with (A) an ethylene-glycidyl methacrylate copolymer.

[(A) Ethylene-glycidyl methacrylate copolymer (EGMA)]
The content of glycidyl methacrylate in the structural unit of (A) ethylene-glycidyl methacrylate copolymer according to this embodiment is preferably 2 to 20% by weight.

  (A) In ethylene-glycidyl methacrylate copolymer, by making content of glycidyl methacrylate 2% by weight or more, (B) vinyl copolymer obtained by polymerizing vinyl monomer composition and good Can be graft copolymerized.

  Moreover, in the (A) ethylene-glycidyl methacrylate copolymer, the slidability of the polyacetal resin composition is improved by setting the content of glycidyl methacrylate to 20% by weight or less.

[(B) Vinyl monomer composition]
The (B) vinyl monomer composition according to this embodiment includes (b-1) a vinyl monomer containing styrene, (b-3) a polymerization initiator, and (b-4) 3-mercaptopropionic acid. And containing.

  The (B) vinyl monomer composition may further contain (b-2) acrylonitrile. When the (B) vinyl monomer composition contains (b-2) acrylonitrile, the compatibility of the obtained (Y) graft copolymer with the (X) polyacetal resin can be improved. Thereby, the polyacetal resin composition excellent in slidability is obtained.

  (B) Content of each monomer (b-1), (b-2), (b-3), (b-4) in a vinyl monomer composition can be determined suitably. However, if the total of (A) the content of the ethylene-glycidyl methacrylate copolymer and (B) the content of the vinyl monomer composition is 100 parts by weight, (A) the ethylene-glycidyl methacrylate copolymer The content of the polymer is preferably 50 to 90 parts by weight, and the content of the (B) vinyl monomer composition is preferably 10 to 50 parts by weight. As a result, a polyacetal resin composition having particularly excellent sliding properties and mechanical properties can be obtained.

  (B) In the vinyl monomer composition (b-1) As the vinyl monomer containing styrene, in addition to styrene, for example, methyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate 2-ethylhexyl acrylate, lauryl acrylate, stearyl acrylate, behenyl acrylate, methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, methacryl Vinyl monomers such as α, β-unsaturated carboxylic acid esters such as stearyl acid and behenyl methacrylate may be included.

  (B) The polymerization initiator (b-3) in the vinyl monomer composition is not limited to a specific type, and known ones such as organic peroxides and azo initiators can be used.

  (B-3) Examples of the organic peroxide that can be used as a polymerization initiator include t-butyl peroxyneoheptanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, di (3 , 5,5-trimethylhexanoyl) peroxide, dilauroyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, 2,5-dimethyl-2,5-di ( 2-ethylhexanoylperoxy) hexane, t-hexylperoxy-2-ethylhexylhexanoate, di (4-methylbenzoyl) peroxide, t-butylperoxy-2-ethylhexanoate, dibenzoyl peroxide Etc.

  (B-3) Examples of the azo compound that can be used as a polymerization initiator include 2,2-azobis (2,4-dimethylvaleronitrile), 2,2-azobis (isobutyronitrile), 2,2- And azobis (2-methylbutyronitrile).

  (B-4) 3-Mercaptopropionic acid in the (B) vinyl monomer composition plays a role as a chain transfer agent in the polymerization of the (B) vinyl monomer composition. Specifically, (b-1) at the time of the polymerization reaction of the vinyl monomer containing styrene, (b-1) the terminal radical of the polymer composed of the vinyl monomer containing styrene, 3-mercaptopropionic acid, Reacts to produce free radicals containing carboxylic acid. The free radical undergoes a polymerization reaction with the vinyl monomer containing (b-1) styrene, whereby a terminal carboxylic acid-modified styrene copolymer is obtained.

<Ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified styrene copolymer composition>
The ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified styrene copolymer composition according to the present embodiment comprises (B) a vinyl monomer composition impregnated in an ethylene-glycidyl methacrylate copolymer resin composition. Obtained by polymerization. (B) The vinyl monomer composition is polymerized by the reaction mechanism described above, and becomes (A) a terminal carboxylic acid-modified styrene copolymer impregnated in the ethylene-glycidyl methacrylate copolymer. In addition, (b-1) When the vinyl monomer containing styrene is only styrene, an ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified polystyrene composition is obtained.

<Polyacetal resin composition>
The polyacetal resin composition according to the present embodiment contains (X) a polyacetal resin and (Y) a graft copolymer.

[(X) Polyacetal resin]
(X) The polyacetal resin can be produced by a known production method. (X) Either a polyacetal homopolymer or a polyacetal copolymer may be used for the polyacetal resin. As the base resin of (X) polyacetal resin, a polyacetal modified by crosslinking or graft copolymerization by a known method can be used. (X) The degree of polymerization of the polyacetal resin and the structure of the terminal group are not limited to specific ones.

[(Y) Graft copolymer]
The (Y) graft copolymer which concerns on this embodiment is obtained by melt-kneading said ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid modified styrene copolymer composition. In the ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified styrene copolymer composition, (B) vinyl monomer composition is impregnated in (A) ethylene-glycidyl methacrylate copolymer, In the (Y) graft copolymer after kneading, a structure in which a fine resin is uniformly dispersed is obtained.

  As a specific reaction, (A) the epoxy group of ethylene-glycidyl methacrylate copolymer and the carboxyl group of terminal carboxylic acid-modified styrene copolymer react by melt kneading, and (Y) graft copolymer Is obtained.

  (Y) The main chain of the graft copolymer comprises (A) an ethylene-glycidyl methacrylate copolymer. The side chain of (Y) graft copolymer consists of (B) vinyl copolymer obtained by superposing | polymerizing a vinyl monomer composition.

  By adding the (Y) graft copolymer to the (X) polyacetal resin, the slidability of the polyacetal resin composition is improved. On the other hand, the mechanical properties and appearance quality of the polyacetal resin composition are improved by keeping the content of the (Y) graft copolymer at a constant amount. For this reason, the content of the (Y) graft copolymer can be appropriately determined depending on the desired slidability, mechanical properties, and appearance quality.

  The content of the (Y) graft copolymer is preferably 3 to 20 parts by weight when the content of the (X) polyacetal resin is 100 parts by weight.

[Polycarboxylic acid]
The polyacetal resin composition according to this embodiment may contain a polyvalent carboxylic acid. Thereby, the slidability of the polyacetal resin composition is improved.

  The polyvalent carboxylic acid is not limited to a specific type, and examples thereof include adipic acid, oxalic acid, succinic acid, and butanetetracarboxylic acid.

  The content of the polyvalent carboxylic acid is preferably 0.1 to 1 part by weight when the content of the (X) polyacetal resin is 100 parts by weight.

[Other additives]
The polyacetal resin composition according to the present embodiment may contain additives other than the above as necessary. Examples of such additives include mineral oils, hydrocarbons, fatty acids, alcohols, fatty acid esters, fatty acid amides, lubricants such as metal soaps, natural waxes, silicones, inorganic flame retardants such as magnesium hydroxide and aluminum hydroxide, Organic flame retardants such as halogen and phosphorus, metal powder, talc, glass fiber, carbon fiber, wood powder and other organic or inorganic fillers, antioxidants, UV inhibitors, lubricants, dispersants, coupling agents, Examples thereof include additives such as a foaming agent, a crosslinking agent, and a colorant, and engineering plastics such as other polyolefin resins, polyesters, polycarbonates, ABS resins, and polyphenylene ethers.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

<Graft copolymer>
[Production of graft copolymer]
For Examples 1-1 to 1-4, 2-1 to 2-5, and Comparative Examples 1-1 to 1-4, graft copolymers were produced with the compositions shown in Table 1. As an example of this, the production process of the graft copolymer according to Example 1-1 is shown below. In addition, the graft copolymer which concerns on another Example and a comparative example was also manufactured by the process similar to Example 1-1.

[Example 1-1]
(Production of ethylene-glycidyl methacrylate copolymer resin composition)
In a 5 L stainless steel autoclave, 2500 g of pure water was added, and 2.5 g of polyvinyl alcohol was dissolved as a suspending agent. 700 g of ethylene-glycidyl methacrylate copolymer (trade name “Bond First E”, manufactured by Sumitomo Chemical Co., Ltd., GMA content 12%, MFR = 3 (g / 10 min)) is added to this, and dispersed by stirring. I let you.

  Separately from this, 1.5 g of di (3,5,5-trimethylhexanoyl) peroxide (trade name “Perroyl 355”, manufactured by NOF Corporation), which is a radical polymerization initiator, and 3 which is a chain transfer agent. -A solution was prepared by dissolving 1.5 g of mercaptopropionic acid in 300 g of styrene (St), and this solution was put into an autoclave and stirred.

  Then, the autoclave is heated to 60 to 65 ° C. and stirred for 2 hours, whereby a monomer composition containing a radical polymerization initiator, 3-mercaptopropionic acid and styrene is added to the ethylene-glycidyl methacrylate copolymer. By impregnating, an ethylene-glycidyl methacrylate copolymer resin composition was obtained.

(Production of ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified polystyrene composition)
Next, the temperature of the autoclave is raised to 80 to 85 ° C., and the ethylene-glycidyl methacrylate copolymer resin composition is polymerized while being held at that temperature for 7 hours. The pellet of the ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid modified polystyrene composition impregnated in the ethylene-glycidyl methacrylate copolymer was obtained.

  The terminal carboxylic acid-modified polystyrene was extracted with ethyl acetate from the pellets of the obtained ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified polystyrene composition. As a result of measurement by gel permeation chromatography (GPC), it was found that the weight average molecular weight of the terminal carboxylic acid-modified polystyrene was 380,000.

(Production of graft copolymer)
The resulting ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified polystyrene composition pellets are melt-kneaded at 200 ° C. with a Laboplast mill single screw extruder (manufactured by Toyo Seiki Seisakusho) and grafted. As a result, white pellets of a graft copolymer having a main chain composed of an ethylene-glycidyl methacrylate copolymer and a side chain composed of polystyrene were obtained.

  When the obtained graft copolymer was observed with a scanning electron microscope (“JEOL JSM T300”, manufactured by JEOL Ltd.), a true spherical resin having a particle size of 0.1 to 0.2 μm was uniformly dispersed. It was confirmed.

[Description of Examples 2-1 to 2-5]
In the graft copolymers according to Examples 2-1 to 2-5, (b-2) acrylonitrile (AN) is contained in the (B) vinyl monomer composition which is a raw material. Thus, in the graft copolymers according to Examples 2-1 to 2-5, the main chain is composed of an ethylene-glycidyl methacrylate copolymer, and the side chain is composed of a vinyl copolymer (styrene acrylonitrile copolymer). .

[Description of Comparative Examples 1-1 to 1-4]
In the graft copolymer according to Comparative Example 1-1, unlike the above embodiment, (b-4) 3-mercaptopropionic acid is not included in the raw material (B) vinyl monomer composition.

  In the graft copolymer according to Comparative Example 1-2, unlike the above embodiment, (b-4) n-dodecyl mercaptan is used instead of 3-mercaptopropionic acid.

  In the graft copolymer according to Comparative Example 1-3, unlike the above embodiment, (b-4) 2-mercaptoacetic acid is used instead of 3-mercaptopropionic acid.

In the graft copolymer according to Comparative Example 1-4, instead of (A) the ethylene-vinyl acetate copolymer, low-density polyethylene (LDPE) (“SUMIKAcene G401”, manufactured by Sumitomo Chemical Co., Ltd., density = 0.926 g / cm ³ ) is used.

The meaning of each abbreviation in Table 1 is as follows.
EGMA: ethylene-glycidyl methacrylate copolymer GMA: glycidyl methacrylate LDPE: low density polyethylene St: styrene AN: acrylonitrile R355: di (3,5,5-trimethylhexanoyl) peroxide 3-MPA: 3-mercaptopropion Acid NDM: n-dodecyl mercaptan 2-MAA: 2-mercaptoacetic acid

<Polyacetal resin composition>
[Production of polyacetal resin composition]
About Examples 3-1 to 3-10, 4-1, 4-2 and Comparative Examples 2-1 to 2-5, polyacetal resin (trade name “Duracon M90-44”, poly The above-mentioned graft copolymer was appropriately dry blended with Plastics Co., Ltd. and melt-kneaded with a twin screw extruder set at 190 ° C. to obtain pellets of a polyacetal resin composition. In Table 2, polyacetal resin is abbreviated as “POM”.

  In Examples 3-1 to 3-10, the graft copolymers obtained in Examples 1-1 to 1-4 and 2-1 to 2-5 were used, respectively, and in Comparative Examples 2-2 to 2-5, respectively. The graft copolymers according to Comparative Examples 1-1 to 1-4 were used.

  The polyacetal resin composition according to Examples 4-1 and 4-2 contains adipic acid as a polyvalent carboxylic acid.

  In addition, the polyacetal resin composition which concerns on Comparative Example 2-1 was manufactured only by polyacetal resin, without using a graft copolymer.

[Evaluation method]
-Tensile strength Based on JIS K-7113, it carried out as test speed 50mm / min.

-Flexural modulus Based on JIS K-7203, it carried out as test speed 2mm / min.

・ Slidability evaluation 1 (Thrust-type friction and wear test)
Testing machine: Friction and abrasion testing machine EFM-III-F manufactured by Orientec Co., Ltd.
Evaluation material: Cylindrical material having an inner diameter of 20 mm and an outer diameter of 25.6 mm Evaluation material material: Polyacetal resin composition having the composition shown in Table 2 Partner material: Cylindrical material having an inner diameter of 20 mm and an outer diameter of 25.6 mm Counterpart material: (1) Carbon Steel (S45C), (2) Same material as the evaluation material Test conditions (when the mating material is (1)): Load 50N, linear velocity 50cm / sec
Test conditions (when the mating material is (2)): Load 20N, linear velocity 50cm / sec
Test time: 100 minutes In this test, the wear amount (mg) and the dynamic friction coefficient of each evaluation material were determined for each counterpart material (1) and (2).

・ Slidability evaluation 2 (reciprocating sliding test)
Testing machine: Rubbing tester 1566-A manufactured by Imoto Seisakusho Co., Ltd.
Evaluation material: flat plate having a length of 80 mm, a width of 10 mm, and a height of 4 mm Evaluation material: Polyacetal resin composition having the composition shown in Table 2 Counter material: Column material having a diameter of 10 mm Counter material: Duracon M90-44 (polyplastics stock) Company-made)
Test conditions: Load 3 kgf, linear velocity 100 mm / sec, 5000 reciprocations In this test, the wear amount (mg) of each evaluation material was determined.

[Production of evaluation materials]
Examples 3-1 to 3-10, 4-1 and 4-2 and Examples 3-1 to 3 by molding the polyacetal resin compositions according to Comparative Examples 2-1 to 2-5 with an injection molding machine Evaluation materials according to -10, 4-1, 4-2 and Comparative Examples 2-1 to 2-5 were produced. The injection molding conditions were a barrel temperature of 200 ° C. and a mold temperature of 90 ° C.

  Table 2 shows the evaluation results of the evaluation materials according to Examples 3-1 to 3-10, 4-1, 4-2, and Comparative Examples 2-1 to 2-5.

[Evaluation results]
-Mechanical properties In all of the evaluation materials according to Examples 3-1 to 3-10, 4-1, and 4-2, a large value of 50 MPa or more was obtained as the tensile strength, and the bending elastic modulus was 1.5 GPa or more. A high value was obtained. On the other hand, (b-4) Evaluation material according to Comparative Example 2-4 using 2-mercaptoacetic acid instead of 3-mercaptopropionic acid, and (A) Low density instead of ethylene-vinyl acetate copolymer In the evaluation material according to Comparative Example 2-5 using polyethylene (LDPE), the tensile strength was a small value of less than 50 MPa.

-Sliding evaluation In the evaluation materials according to Examples 3-1 to 3-10, 4-1, and 4-2, in the thrust type frictional wear test in which the counterpart material is (1) carbon steel (S45C), A small value of 2.0 mg or less was obtained as the wear amount, and a low value of 0.25 or less was obtained as the dynamic friction coefficient. In particular, in the evaluation materials according to Examples 4-1 and 4-2 containing adipic acid as the polyvalent carboxylic acid, the wear amount was a smaller value.

  Moreover, in all of the evaluation materials according to Examples 3-1 to 3-10, 4-1, and 4-2, the counterpart material is the same as the evaluation material, that is, a thrust type frictional wear test between the evaluation materials. The wear amount was as small as 2.0 mg or less, and the dynamic friction coefficient was as low as 0.25 or less.

  Furthermore, in the evaluation materials according to Examples 3-1 to 3-10, 4-1, and 4-2, in the reciprocating sliding test, a small value of 10.0 mg or less was obtained as the wear amount. In particular, in the evaluation materials according to Examples 4-1 and 4-2 containing adipic acid as the polyvalent carboxylic acid, the wear amount was a smaller value.

  On the other hand, in the evaluation materials according to Comparative Examples 2-1 to 2-5, in the thrust type frictional wear test in which the counterpart material is (1) carbon steel (S45C), the wear amount is greater than 2.0 mg. Met. In addition, in the evaluation material according to Comparative Example 2-1, which does not include the (Y) graft copolymer, the coefficient of dynamic friction was higher than 0.25.

  Moreover, in the evaluation materials according to Comparative Examples 2-1 to 2-5, the wear amount is 2. even in the thrust type frictional wear test between the evaluation materials, in which the counterpart material is the same as the evaluation material. The value was greater than 0 mg. In addition, in the evaluation material according to Comparative Example 2-1, which does not include the (Y) graft copolymer, the coefficient of dynamic friction was also higher than 0.25.

  Furthermore, in the evaluation materials according to Comparative Examples 2-1 to 2-5, the wear amount was a value larger than 10.0 mg in the reciprocating sliding test.

  The embodiment of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention.

Claims (8)

(A) an ethylene-glycidyl methacrylate copolymer and (B) a vinyl monomer composition,
The (B) vinyl monomer composition includes (b-1) a vinyl monomer containing styrene, (b-3) a polymerization initiator, and (b-4) 3-mercaptopropionic acid. The (A) ethylene-glycidyl methacrylate copolymer is impregnated with the ethylene-glycidyl methacrylate copolymer resin composition. The ethylene-glycidyl methacrylate copolymer resin composition according to claim 1,
The (B) vinyl monomer composition further comprises (b-2) acrylonitrile. An ethylene-glycidyl methacrylate copolymer resin composition. The ethylene-glycidyl methacrylate copolymer resin composition according to claim 1 or 2,
When the total of the content of the (A) ethylene-glycidyl methacrylate copolymer and the content of the (B) vinyl monomer composition is 100 parts by weight,
The content of the (A) ethylene-glycidyl methacrylate copolymer is 50 to 90 parts by weight,
The ethylene-glycidyl methacrylate copolymer resin composition, wherein the content of the (B) vinyl monomer composition is 10 to 50 parts by weight. The ethylene-glycidyl methacrylate copolymer resin composition according to any one of claims 1 to 3,
The (A) ethylene-glycidyl methacrylate copolymer contains 2 to 20% by weight of glycidyl methacrylate. An ethylene-glycidyl methacrylate copolymer resin composition. An ethylene-glycidyl methacrylate copolymer / obtained by polymerizing the (B) vinyl monomer composition impregnated in the ethylene-glycidyl methacrylate copolymer resin composition according to any one of claims 1 to 4. Terminal carboxylic acid-modified styrene copolymer composition. It is obtained by melt-kneading the ethylene-glycidyl methacrylate copolymer / terminal carboxylic acid-modified styrene copolymer composition according to claim 5,
The main chain is composed of the (A) ethylene-glycidyl methacrylate copolymer,
A graft copolymer comprising a vinyl copolymer whose side chain is obtained by polymerizing the vinyl monomer composition (B). (X) a polyacetal resin and (Y) the graft copolymer according to claim 6,
When the content of the (X) polyacetal resin is 100 parts by weight, the polyacetal resin composition in which the content of the graft copolymer according to (Y) is 6 to 20 parts by weight. The polyacetal resin composition according to claim 7,
(Z) further containing a polyvalent carboxylic acid,
A polyacetal resin composition in which the content of the (Z) polyvalent carboxylic acid is 0.1 to 1 part by weight when the content of the (X) polyacetal resin is 100 parts by weight.