JPH1149900A - Lubricant resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition that maintains the mechanical properties intrinsic to this resin, can manifest excellent moldability, abrasive resistance and low friction, thus is useful for precision instrument. SOLUTION: (A) To a polyolefin resin as polyethylene resin, are formulated (B) 1-15 wt.% of a dimethylsilicon bearing no functional group [for example, a compound of the formula (n is a polymerization degree that reveals a specific kinetic viscosity) with a kinetic viscosity of 100-100,000 mm<2> /sec (cSt) at 25 deg.C] and, when necessary, (C) 0.05-15 wt.% of a 5-32C fatty acid as caproic, melissic, oleic or ricinioleic acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a lubricating resin composition, and more particularly, to a lubricating resin composition used for a sliding member.

[0002]

2. Description of the Related Art As OA equipment, mainly copiers, and porcelain recording devices, such as video tape recorders (VTRs), have become lighter and more compact, stricter sliding has been applied to sliding members such as bearings. Dynamic characteristics have been required. To solve this, as resins conventionally used for sliding members such as the above bearings, polyethylene, polyacetal, polyamide,
So-called engineering plastics such as polybutylene terephthalate are widely used. Such engineering plastics are excellent in self-lubricating properties, so that they perform well even without lubrication under low-load conditions, but may not withstand use due to insufficient sliding characteristics under high-load conditions. For this reason, in order to obtain sufficient sliding characteristics even under a high load state, attempts have been made to improve friction characteristics and wear characteristics by blending a lubricating oil or the like with the above resin.

For example, as a guide roller material, a resin composition in which a thermoplastic resin such as polyethylene is mixed with an organopolysiloxane having a functional group (JP-A-63-1462)
No. 61), and lubrication mixed with silicone oil which does not have amino group, epoxy group, alcoholic hydroxyl group, mercapto group, carboxyl group, etc., which are reactive groups to polyethylene, as a guide roller material for magnetic tape. Resin composition (see JP-A-6-195821),
Lubricating resin composition comprising alkyl-modified silicone oil mixed with polyethylene (Japanese Patent Application Laid-Open No. 8-269255)
Etc. are known.

[0004]

However, when a resin composition in which an organopolysiloxane having a functional group is blended with the above-mentioned thermoplastic resin such as polyethylene is used, when the thermoplastic resin is heat-molded, this resin is used. The functional groups react, and voids and cracks are likely to occur in the formed roller. Therefore, it is difficult to obtain stable sliding characteristics and moldability. In addition, when a lubricating resin composition containing a silicone oil having no reactive functional groups such as amino group, epoxy group, alcoholic hydroxyl group, mercapto group, and carboxyl group in polyethylene is used, it is added. The dispersion state and dispersion unit in polyethylene are greatly affected by the viscosity and chemical structure of the silicone oil, and properties such as sliding characteristics, moldability, and bleeding during use are greatly affected.

[0005] Therefore, an object of the present invention is to solve the above-mentioned problems and to provide a resin composition having excellent sliding properties, particularly excellent self-lubricating properties.

[0006]

In order to solve the above-mentioned problems, the present invention comprises 1 to 15% by weight of dimethyl silicone oil having no functional group in a polyolefin resin.

Further, dimethyl silicone oil having no functional group can be used as a dimethylsiloxane polymer, and the side chain portion and the polymer terminal portion of the dimethylsiloxane can be used as a methyl group. Further, the polyolefin resin can be a polyethylene resin. Furthermore, the kinematic viscosity at 25 ° C. of the dimethyl silicone oil having no functional group can be set to 100 to 100,000 mm ² / sec (cSt).

Further, the lubricating resin composition described above may further comprise:
A fatty acid having 5 to 32 carbon atoms may be added to the polyolefin resin contained in the lubricating resin composition in an amount of 0.05 to 15% by weight.

A dimethyl silicone oil having no functional group in the polyolefin resin, for example, a polymer of dimethyl siloxane, wherein a dimethyl silicone oil having a methyl group at a side chain portion and a polymer terminal portion of the dimethyl siloxane is blended. Therefore, without impairing moldability and mechanical properties,
The sliding characteristics of dimethyl silicone oil are stably exhibited on the sliding surface, and excellent friction and wear characteristics are exhibited. Further, by blending a fatty acid having 5 to 32 carbon atoms, the sliding characteristics can be further improved.

[0010]

Embodiments of the present invention will be described below. The lubricating resin composition according to the present invention comprises 1 to 15% by weight of a dimethyl silicone oil having no functional group in a polyolefin resin.

The above-mentioned polyolefin resin is not particularly restricted but includes, for example, polyethylene resin, polypropylene resin, propylene-ethylene block copolymer,
Propylene-ethylene random copolymer, ethylene-propylene elastomer, ethylene-propylene-dicyclopentadiene elastomer, ethylene-acrylate copolymer, ethylene-vinyl acetate copolymer, chlorinated polyolefin resin, modified polyolefin resin, cross-linked polyolefin Resins.

The polyethylene resin is -CH ₂ -CH _2-
It consists of a main chain containing (ethylene group), and is classified into low density, linear low density, medium density, high density, and ultra-high molecular weight polyethylene resins depending on the degree of crystallinity. It may be employed, and may be a linear one or a branched one containing a branch of a methyl group. For such a polyethylene resin, a molding method such as injection molding or extrusion molding applied to a thermoplastic resin, such as melt molding or compression molding, can be employed.

Specifically, low-density polyethylene is about 2
Manufactured under high pressure and high temperature of about 000-3000 atm, about 150-300 ° C, specific gravity is about 0.91-0.925, smaller than other polyethylene resins, crystallinity is 45-55%, and melting point is about 100-120 ° C. It is sometimes called high-pressure polyethylene or soft polyethylene. Medium and high density polyethylene is manufactured at a low temperature and low pressure of 0 to 100 atm and about 50 to 200 ° C, specific gravity of about 0.926 to 0.94, crystallinity of about 50 to 60%, and melting point of about 120 to 125 ° C. And medium
It is sometimes called low-pressure polyethylene or hard polyethylene. In addition, the thing whose specific gravity is 0.926-0.94 may be called medium density polyethylene. Also, among high-density polyethylenes, about 10 to 60 atm, about 100 to 17 atm.
Some are manufactured at 0 ° C medium to low temperature and medium pressure. Specific gravity is about 0.941 to 0.97, crystallinity is about 65 to 85%, and melting point is about 65 to 85 ° C. Also called.

High-pressure polyethylene has many branches in long linear molecules and is resistant to heat and ultraviolet rays. Medium- and low-pressure polyethylene has some branching, double bonds, good molecular orientation, moderately hard, and its feasibility as a molded product during molding, moldability and abrasion resistance. Etc. are excellent. High pressure polyethylene has a viscosity average molecular weight of about 1
It can be set to 500,000, and among them, those having 10,000 to 150,000 and those having 100,000 to 400,000 are preferable.

On the other hand, the ultra-high molecular weight polyethylene has a limiting viscosity by melt viscosity method of 8 to 40 dl · g, an average viscosity of 1 × 10 ⁶ to 8 × 10 ⁶ and a density of 0.9.
2 to 0.94 g / cm ³ . The degree of crystallinity is almost the same as in the case of the high-density polyethylene described above.

By increasing the density and the molecular weight as described above, various properties such as abrasion resistance, self-lubricating property, impact resistance, chemical resistance, light weight that is lighter than the specific gravity of water, dimensional stability due to low water absorption, etc. Excellent in various properties. In addition, a material containing an ultrahigh molecular weight component and adding injection molding performance with low molecular weight polyethylene is also preferable.

Examples of the polyethylene resin include low-molecular-weight polyethylene, modified polyethylene comprising a graft copolymer, chlorinated polyethylene, cross-linked polyethylene, foamed polyethylene and the like, in addition to the above-mentioned ones. Further, as the above-mentioned polyethylene resin, two or more types of each polyethylene can be used in addition to a single resin. The blending ratio is not particularly limited, but is, for example, 1 to 80 parts by weight, preferably 5 to 50 parts by weight, more preferably 25 to 40 parts by weight, based on 100 parts by weight of the predetermined polyethylene as the main component. can do.

Examples of commercially available polyethylene resins include HIZEX, HIZEX Million, Lubmar, manufactured by Mitsui Petrochemical Industries, Ltd., and Hostalen, manufactured by Hoechst.

The above-mentioned dimethyl silicone oil having no functional group in the polyolefin resin is a polymer of dimethyl siloxane, and the side chain portion and the polymer terminal portion of the dimethyl siloxane are methyl groups. Moreover, kinematic viscosity at 25 ° C. of dimethyl silicone oil without the functional group is from 100 to 100,000 mm ² / sec (cSt) is preferred, 1,000 to 60,000 mm ² / sec (cSt) is preferred. If it is less than 100 mm ² / sec (cSt), the dynamic characteristics are not good, and 100,000 mm ² / sec (cS
If t) is exceeded, the mixing and dispersibility in the resin will deteriorate. Examples of such dimethyl silicone oil include:
A compound represented by the following chemical formula [1] is exemplified.

[0020]

Embedded image

(In the formula, n represents a degree of polymerization sufficient for the dimethyl silicone oil represented by the formula to exhibit the above kinematic viscosity.)

The blending amount of the dimethyl silicone oil with respect to the polyolefin resin is 1 to 15% by weight,
It is preferably from 3 to 12% by weight, more preferably from 5 to 10% by weight. If the amount is less than 1% by weight, the sliding characteristics cannot be sufficiently improved. If the amount exceeds 15% by weight, the resin may slip on the screw of the extruder at the time of kneading or the mechanical characteristics may be impaired. It is.

The method of mixing the polyolefin resin and the dimethyl silicone oil may be a conventionally known method. For example, the polyolefin resin and the dimethyl silicone oil, which are base materials, are each individually or appropriately dissolved in a solvent such as fluorochlorohydrocarbon, and mixed by a Henschel mixer, a ball mill, a tumbler mixer or the like, and then mixed. The solvent is removed and supplied to a melt extruder such as an injection molding machine or a twin screw extruder with good melt mixing properties, or melt mixed in advance using a heat roller, kneader, Banbury mixer, melt extruder, etc. You may. Also, if the medium / high-density polyethylene or ultra-high molecular weight polyethylene is granulated once to form a pellet and then melt-extruded, a molded body having good physical properties can be obtained efficiently.

As a method for molding the lubricating resinous composition according to the present invention, any of extrusion molding, injection molding, compression molding, vacuum molding, blow molding and foam molding can be employed. Among these, injection molding and extrusion molding are preferred.

Further, the lubricating resin composition may contain 0.05 to 15% by weight of a fatty acid having 5 to 32 carbon atoms relative to the polyolefin resin contained in the lubricating resin composition. By adding the above fatty acid to form a fatty acid-containing lubricating resinous composition, the sliding characteristics can be further improved.

The fatty acids having 5 to 32 carbon atoms include:
For example, caproic acid, caprylic acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, palmitic acid,
Saturated fatty acids such as stearic acid, behenic acid, lignoceric acid, sorotic acid, montanic acid, and melicic acid, and unsaturated fatty acids such as oleic acid, elaidic acid, linoleic acid, linolenic acid, arachidonic acid, prasidic acid, erucic acid, and ricinoleic acid Etc. can be given.

The amount of the fatty acid to be added to the polyolefin resin is preferably 0.05 to 20% by weight. 3
-8% by weight is more preferred. If the amount is less than 0.05 part by weight, the sliding characteristics cannot be further improved. If the amount exceeds 20% by weight, resin sliding on the screw of the extruder may occur during kneading, The characteristics may be impaired.

[0028]

Embodiments of the present invention will be described below. Raw materials used in the following Examples and Comparative Examples are collectively shown below. Abbreviations are shown in parentheses.

(1) Polyethylene (PE1) Manufactured by Mitsui Petrochemical Co., Ltd .: HIZEX 1300J (high molecular weight), density 0.965 g / cm ³ (2) Polyethylene (PE2) Manufactured by Mitsui Petrochemical Industry: Lubmer L5000 (high molecular weight) ), Density 0.965 g / cm ³ (3) Polyethylene (PE3) Hoechst, Germany: Hostalen GUR212 (ultra high molecular weight), density 0.935 g / cm ³ (4) Polyacetal (POM) Polyplastic: Duracon M90 (5) Dimethyl silicone (silicone oil 1) manufactured by Shin-Etsu Chemical Co., Ltd .: KF96H-6000 mm ² / sec
c (cSt) (6) Dimethyl silicone (silicone oil 2) manufactured by Shin-Etsu Chemical Co., Ltd .: KF96-500 mm ² / sec
(CSt) (7) Dimethyl silicone (silicone oil 3) manufactured by Shin-Etsu Chemical Co., Ltd .: KF96-100,000 mm ² / s
ec (cSt) (8) Fluorine-modified silicone (Silicone oil 4) Shin-Etsu Chemical Co., Ltd.: FL100-1000mm ² / se
c (cSt) (9) Alkyl-modified silicone (silicone oil 5) manufactured by Shin-Etsu Chemical Co., Ltd .: KF412-500 mm ² / sec
(CSt) (10) Carboxyl-modified silicone (silicone oil 6) manufactured by Shin-Etsu Chemical Co., Ltd .: X22-3701E-3000 mm
² / sec (cSt) (11) Amino and polyether-modified silicone (silicone oil 7) Shin-Etsu Chemical Co., Ltd .: X22-3939A-3300 mm
² / sec (cSt) (12) Higher fatty acid ester-modified silicone (silicone oil 8) manufactured by Shin-Etsu Chemical Co., Ltd .: X22-715-14800 mm ²
/ Sec (cSt) (13) Hydrophilic specially modified silicone (silicone oil 9) Shin-Etsu Chemical Co., Ltd .: KF905-700 mm ² / sec
(CSt) (14) Methylphenyl-modified silicone (silicone oil 10) manufactured by Shin-Etsu Chemical Co., Ltd .: KF50-3000 mm ² / sec
(CSt) (15) Polyether-modified silicone (silicone oil 1
1) Shin-Etsu Chemical Co., Ltd.: KF352-1500mm ² / se
c (cSt) (16) Stearic acid Wako Pure Chemical Industries, Ltd .: Reagent [Examples 1-4, 6-9, Comparative Examples 1-11] Table 1 or Table 2 as polyolefin resin, dimethyl silicone oil, and fatty acid Table 1 or Table 2
After thoroughly mixing with a Henschel mixer with the composition shown in
It was supplied to a twin screw extruder, extruded under the melt extrusion conditions shown in Table 1 or Table 2, and granulated. Using the obtained pellets, a cylinder temperature of 170 ° C., a mold temperature of 140 ° C. (extruder side), 90 ° C. (tip side), a screw rotation speed of 1 with a single-screw extruder having a screw outer diameter of 32 mm.
A bar having an outer diameter of 5.8 mm was formed under the condition of 0 rpm. Further, the bar was cut into a bar of φ3 × L13.

For the polyacetal resin of Comparative Example 11, pellets melt-mixed under the conditions shown in Table 2 were used.
Under the injection molding conditions shown in Table 2, outer diameter 8 mm, length 15 m
m was molded, and the molded body was cut in the same manner as above to produce a bar.

Each of the obtained bars was subjected to surface pressure of 3 kgf / cm ² and speed of 40 using a pin-on-disk friction and wear tester.
A friction and wear test was performed under the conditions of m / min and the mating material SUS420J2. Table 3 shows the results.

Example 5 The polyolefin resin and dimethyl silicone oil shown in Table 1 were thoroughly mixed with the composition shown in Table 1 using a Henschel mixer.
Heat and pressure molding was performed at a temperature of 500 ° C. and a pressure of 500 kgf / cm ² to obtain a molded body having an outer diameter of 20 mm and a length of 50 mm. This compact was cut to produce a bar having the same shape as in Example 1. The bar thus obtained was subjected to a friction and wear test according to the method described above. Table 3 shows the results.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

Results As is evident from the results in Table 3, the coefficient of friction was large in Comparative Example 11 in which the substrate was other than polyethylene. On the other hand, in Examples 1 to 9, the friction coefficient was stably low and no tendency to increase was observed.

In Comparative Example 2, the resin material penetrated (bitten) into the screw of the extruder, and was not able to be melt-mixed. On the other hand, in Examples 1 to 9, the specific wear amount was small, the friction coefficient was low and stable, and the moldability was good.

Therefore, the sliding members using the lubricating resin compositions of Examples 1 to 9 can realize low friction and low wear.

[0039]

According to the present invention, since dimethyl silicone oil having no functional group is blended, stable moldability is exhibited without delamination, and excellent mechanical properties of the polyolefin resin are impaired. It is possible to obtain an excellent lubricating resin which has no wear, has excellent abrasion resistance, and has no change in friction coefficient over time.

When the obtained lubricating resin is used for precision equipment such as VTR and DAT or general equipment, the weight, cost and torque of these equipment can be reduced.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI // (C08L 23/00 83:04) C10N 40:02

Claims (5)

[Claims] 1. A lubricating resin composition comprising 1 to 15% by weight of dimethyl silicone oil having no functional group in a polyolefin resin. 2. The lubricating resin according to claim 1, wherein the dimethyl silicone oil having no functional group is a polymer of dimethyl siloxane, and the side chain portion and the terminal portion of the dimethyl siloxane are methyl groups. Composition. 3. The lubricating resin composition according to claim 1, wherein the polyolefin resin is a polyethylene resin. 4. A dimethyl silicone oil having no functional group having a kinematic viscosity at 25 ° C. of 100 to 100,000 mm ² / sec.
The lubricating resin composition according to any one of claims 1 to 3, which is (cSt). 5. The lubricating resin composition according to claim 1, wherein a fatty acid having 5 to 32 carbon atoms is added to the polyolefin resin contained in the lubricating resin composition in an amount of 0.05 to 5%. A fatty acid-containing lubricating resinous composition containing 15% by weight.