JP3389933B2 - Polyacetal resin composition - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyacetal resin composition having excellent self-lubricating properties without impairing the original properties of the polyacetal resin. More specifically, in the present invention, a specific acryl derivative is added to and blended with the polyacetal resin, and the mixture is uniformly melt-kneaded. Alternatively, the present invention relates to a polyacetal resin composition having improved self-lubricating properties, which is obtained by adding and blending a specific acryl derivative and a radical initiator to a polyacetal resin, and uniformly melting and mixing them.

[0002]

2. Description of the Related Art Polyacetal resins are widely used in the fields of electricity / electronics, construction, automobiles, etc. because of their excellent mechanical properties, abrasion / wear resistance, fatigue resistance, chemical resistance, and electrical properties. In addition, since polyacetal resin is also excellent in self-lubricating property, there are many applications that make use of its characteristics, and in particular, it has the high self-lubricating property required for electric / electronic equipment, office equipment, automobiles, industrial equipment, etc. It is used as a material for sliding parts such as intended bearings, gears, rollers, sliding plates, levers and guides.

However, the required characteristics in such fields are becoming more and more sophisticated, and for example, it is not always sufficient in applications where sliding characteristics are required, and further improvement of self-lubricating characteristics is desired. Conventionally, in order to further improve the lubricating properties of polyacetal resins, for example, Japanese Patent Publication No. 46-5321 discloses a method in which polyacetal is impregnated with oil. However, this method has a drawback in that oil retention is poor and moldability is poor.

Further, Japanese Patent Publication No. 62-253650 discloses a method of adding polyethylene having a melt index of 10 or more to a polyacetal resin, and Japanese Laid-Open Patent Publication No. 57-5714 discloses a polyacetal containing an ester lubricant and a low density polyethylene. Method of combining, JP-A-2-1383
No. 57 discloses a method of combining a polyacetal with a graft copolymer having polyolefin as a main chain polyacrylate as a side chain and a fatty acid or fatty acid ester having a total carbon number of 12 or more. Even in this case, since the compatibility of polyethylene or an olefin-based graft copolymer with polyacetal is poor, delamination is likely to occur, and general physical properties such as mechanical properties are significantly deteriorated.

[0005]

The present invention solves the above problems and impairs the excellent mechanical properties, electrical properties, fatigue resistance, chemical resistance, etc. of the inherent polyacetal resin. It is an object of the present invention to provide a polyacetal resin composition having excellent self-lubricating properties.

[0006]

That is, according to the present invention, a specific acryl derivative is added to and blended with a polyacetal resin, and the mixture is uniformly melt-kneaded. Alternatively, the present invention relates to a polyacetal resin composition having improved self-lubricating properties, which is obtained by adding and blending a specific acryl derivative and a radical initiator to a polyacetal resin and uniformly melt-kneading the mixture. More specifically, the present invention relates to a polyacetal resin (A)
For 100 parts by weight, the following formula

[0007]

[Chemical 3]

By adding and blending 0.10 to 10.0 parts by weight of an acrylic derivative (B) represented by [R1 is hydrogen or a methyl group, and R2 is an aliphatic alkyl group having 8 or more carbon atoms]. , Uniformly melt-kneaded, or based on 100 parts by weight of the polyacetal resin (A), the following formula

[0009]

[Chemical 4]

0.10 to 10.0 parts by weight of an acrylic derivative (B) represented by [R1 is hydrogen or a methyl group, and R2 is an aliphatic alkyl group having 8 or more carbon atoms], and
Add 0.01 to 1.0 parts by weight of radical initiator (C).
The present invention relates to a polyacetal resin composition having improved self-lubricating properties, which is obtained by blending and uniformly kneading.

In the present invention, the polyacetal resin (A) means a polyacetal (polyoxymethylene) and a polyacetal copolymer which are already commercially available. More specifically, for example, formaldehyde or its trimer (trioxane),
And an oxymethylene homopolymer substantially composed of an oxymethylene unit structure produced from the tetramer (tetraoxane) as a raw material, and / or formaldehyde, or a trimer thereof (trioxane), and its quaternary amount Body (tetraoxane) and ethylene oxide, epichlorohydrin, 1,3-dioxolane, 1,
Oxygen containing 0.10 to 20% by weight of an oxyalkylene unit structure produced from a cyclic ether having 2 to 8 carbon atoms, such as 3,5-trioxepane, glycol formal, diglycol formal, and diglycol formal. Methylene copolymer, and / or oxymethylene homopolymer, or block structure other than oxymethylene unit structure having oxymethylene copolymer as a main structure, or oxymethylene block copolymer having a terminal structure, or oxymethylene graft polymer, or It means a known oxymethylene crosslinked polymer having a crosslinked structure.

The acrylic derivative (B) to be added / blended in the present invention means the following general formula

[0013]

[Chemical 5]

An ester compound of an aliphatic alkyl having 8 or more carbon atoms derived from acrylic acid or methacrylic acid, wherein R1 is hydrogen or a methyl group, and R2 is an aliphatic alkyl group having 8 or more carbon atoms. Means that. More specifically, for example, lauryl methacrylate, dodecyl pentadecyl methacrylate, 2-ethylhexyl methacrylate, behenyl methacrylate, cetyl methacrylate, stearyl methacrylate, stearyl acrylate and the like can be mentioned.

The acrylic derivative according to the present invention may be in any physical state such as liquid, powder, flakes and lumps, and it is included in the present invention.

When carrying out the present invention, the amount of the acrylic derivative (B) compounded is 0.10 to 10.0 parts by weight, preferably 0.5 parts by weight, based on 100 parts by weight of the polyacetal resin.
0 to 5.0 parts by weight. When an amount exceeding 10.0 parts by weight is used, the molding characteristics of the polyacetal deteriorate, and
If it is 10 or less, the effect of the present invention is small.

When carrying out the present invention, the acrylic derivative (B) may be used alone or in a combination of two or more as long as it is in the range of 0.10 to 10.0 parts by weight. May be used.

In the present invention, the radical initiator (C) to be added / blended means a peroxide or an azo compound which generates radicals when the polyacetal is melted / kneaded. More specifically, for example, t-butyl hydroperoxide, diisopropylbenzene hydroperoxide, α, α′-bis (t-butylperoxide-m-isoperopyr) benzene, di-t-butylperoxide, t-butylclucene. Mill peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di (t
-Butylperoxy) hexane, 2,5-dimethyl-
2,5-di (t-butylperoxy) -3-hexane,
1,1-bis (t-butyl peroxide) -3,3,5
-Peroxides such as trimethylcyclohexane, 4,4-bis- (t-butylperoxide) valerate-n-butyl, or azobisisobutyronitrile, 1,1'-
Azo compounds such as azobisformamide can be mentioned.

When carrying out the present invention, the content of the radical initiator (C) is 0.01 to 1.0 parts by weight, preferably 0.03 parts by weight, based on 100 parts by weight of the polyacetal resin.
~ 0.3 parts by weight. The amount of radical initiator compounded is
If it is less than 0.01 parts by weight, the desired effects of the present invention cannot be sufficiently achieved. On the other hand, if the amount exceeds 1.0 part by weight, excessive decomposition of the polyacetal resin may occur depending on the type of radical initiator used, which is not preferable.

When carrying out the present invention, it is not necessary to select a polyacetal resin having a special quality, and a powder, a flake, or a powder to which a stabilizer, an antioxidant or the like is added is usually used.
The purpose can be sufficiently achieved by appropriately selecting from commercially available polyacetal resins such as pellets in consideration of the application.

When carrying out the present invention, the polyacetal resin composition of the present invention may further contain, if desired, carbon black, known fillers, pigments, antioxidants, antistatic agents, light stabilizers, nucleating agents and the like. One or more conventionally known additives can be appropriately added.

When carrying out the present invention, the method of mixing and kneading the polyacetal resin composition of the present invention will be described.
There is no particular limitation, and it can be easily produced by a generally known mixing / kneading device.

The polyacetal composition of the present invention can be easily molded by a generally known molding method, that is, an injection molding method, an extrusion molding method, a compression molding method, a blow molding method, a vacuum molding method, a foam molding method, or the like. be able to.

Hereinafter, the present invention will be described more specifically by way of examples, but is not intended to limit the embodiments of the present invention or the scope of the invention.

[0025]

【Example】

Example 1 Polyacetal resin [Mitsubishi Gas Chemical, Iupital F2
0-01] 100 parts by weight, stearyl methacrylate [Mitsubishi Gas Chemical Co., SMA] 3.0 parts by weight, and 2,5
-Dimethyl-2,5-di (t-butyl peroxide) hexane [Nippon Oil & Fats, Perhexa 25B-40] 0.0
5 parts by weight [see Table 1] were weighed and uniformly mixed using a super mixer [Kawata Seisakusho], and then 2
Axial extruder [Ikegai Tekko, PCM-30, screw diameter 3
0 mm], and after melt-kneading under the conditions of a screw rotation speed of 50 rpm and a cylinder set temperature of 200 ° C.,
Pelletized. Then, after drying the pellets for 4 hours using a hot air dryer at a temperature of 80 ° C., using an in-line screw type injection molding machine [PS-40 manufactured by Nissei Jushi Kogyo], a cylinder temperature of 200 ° C. and a mold temperature of A cylindrical thrust test piece was molded under the operating conditions of 80 ° C. and a molding cycle of 30 seconds. The two cylindrical thrust test pieces obtained here were combined and a thrust type friction and wear tester manufactured by Orientec was used to increase the load by 5 Kgf / cm ^{2 at} a linear velocity of 10 cm / sec and a running time of 5 minutes. Then, the sliding characteristics such as the melting surface pressure, the squeaking sound generating surface pressure, and the dynamic friction coefficient were measured. The results are shown in Table 2.

Examples 2 to 6 In Example 1, in place of 3.0 parts by weight of stearyl methacrylate, 2-ethylhexyl methacrylate [Mitsubishi Gas Chemical Co., Ltd., EHMA], lauryl methacrylate [Mitsubishi Gas Chemical Co., Ltd., LMA] , S-lauryl methacrylate [Mitsubishi Gas Chemical Co., Ltd. SLMA], dodecyl pentadecyl methacrylate [Mitsubishi Gas Chemical Co., Ltd. DPMA], and behenyl methacrylate [Nippon Oil & Fats Co., Ltd. Bremmer VMA], 3.0 parts by weight respectively [Table 1 Reference] The same treatment as in Example 1 was carried out except that it was used, and the results shown in Table 2 were obtained.

Examples 7 to 10 In Example 1, stearyl methacrylate and 2,5-
Except that the compounding amount of dimethyl-2,5-di (t-butylperoxide) hexane was changed to the parts by weight shown in Table 1, the same treatment as in Example 1 was carried out, and the results shown in Table 2 were obtained. Obtained.

Example 11 In Example 1, 2,5-dimethyl-2,5-di (t
-Butyl peroxide) hexane 0.05 parts by weight instead of dicumyl peroxide [NOF, Perkmill D
-40] The same treatment as in Example 1 was carried out except that 0.05 part by weight (see Table 1) was used, and the results shown in Table 2 were obtained.

Example 12 Polyacetal resin [Mitsubishi Petrochemical, Iupital F2
0-01] 100 parts by weight, stearyl methacrylate 3.
The same procedure as in Example 1 was carried out using 0 parts by weight (see Table 1), and the results shown in Table 2 were obtained.

Example 13 The same procedure as in Example 1 was repeated except that the amount of stearyl methacrylate was changed to 5.0 parts by weight (see Table 1) in Example 12, and the results are shown in Table 2. I got the result.

Examples 14 and 15 In Example 12, 3.0 parts by weight of stearyl methacrylate were added to 3.0 parts by weight of lauryl methacrylate, respectively.
Further, the same treatment as in Example 1 was carried out except that the amount of behenyl methacrylate was changed to 3.0 parts by weight (see Table 1), and the results shown in Table 2 were obtained.

Comparative Example 1 Polyacetal resin [Iupital F2 manufactured by Mitsubishi Gas Chemical Co., Inc.
0-01] 100 parts by weight was used and treated in the same manner as in Example 1 to obtain the results shown in Table 2.

Comparative Example 2 Polyacetal resin [Iupital F2 manufactured by Mitsubishi Gas Chemical Co., Inc.
0-03] 100 parts by weight was used and treated in the same manner as in Example 1 to obtain the results shown in Table 2.

[0034]

The polyacetal resin composition of the present invention is obtained by adding and blending a specific acryl derivative to the polyacetal resin and uniformly melt-kneading. Alternatively, a specific acryl derivative and a radical initiator are added to and blended with a polyacetal resin, and the mixture is uniformly melt-kneaded, and the mechanical properties, electrical properties, and fatigue resistance of the polyacetal resin are inherent. It can be suitably used as a material for various sliding parts that have excellent self-lubricating properties without impairing chemical resistance and are required to have high self-lubricating properties and high mechanical strength.

[0035]

[Table 1]

[0036]

[Table 2]

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-50-44286 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C08L 59/00-59/04

Claims (2)

(57) [Claims] Claims: (A) 100 parts by weight of polyacetal resin, (B) the following formula: 0.10 to 10.0 parts by weight of an acrylic derivative represented by [R1 is hydrogen or a methyl group and R2 is an aliphatic alkyl group having 8 or more carbon atoms] is added and blended, and the mixture is uniformly melt-kneaded. A polyacetal resin composition comprising: 2. With respect to 100 parts by weight of (A) polyacetal resin, (B) the following formula: [R1 is hydrogen or a methyl group, R2 is an aliphatic alkyl group having 8 or more carbon atoms] 0.10 to 10.0 parts by weight, and (C) a radical initiator 0.01 A polyacetal resin composition obtained by adding and blending up to 1.0 parts by weight and uniformly melt-kneading.