JPH0751654B2 - Composition for sliding materials - Google Patents

Description

The present invention relates to a composition for a sliding material containing an aromatic vinyl-unsaturated dicarboxylic acid imide copolymer.

Conventionally, a sliding material composition containing a fixed lubricant has been known (Japanese Patent Publication No. S50-5748, Japanese Patent Publication No. S60-6024, and Japanese Patent Publication No. S54-8775).
2).

However, since these sliding material compositions have low heat resistance, their applications are limited.

The present invention has conducted extensive studies to improve this drawback, and as a result, a copolymer containing 35 to 75% by weight of an aromatic vinyl monomer residue and 25 to 65% by weight of an unsaturated dicarboxylic acid imide derivative residue ( Hereinafter often referred to as "aromatic vinyl-unsaturated dicarboxylic acid imide copolymer") 100 parts by weight of a thermoplastic resin containing 15% by weight or more, 0.1 to 100 parts by weight of a solid lubricant and higher fatty acid, higher fatty acid ester, It has been found that a composition containing at least 10 parts by weight (however, not 0 parts by weight) of at least one selected from the group of higher fatty acid amides and silicone oil is superior in friction and wear characteristics and heat resistance than expected, The present invention has been reached.

The thermoplastic resin used in the present invention may be composed of only an aromatic vinyl-unsaturated dicarboxylic acid imide copolymer, but if it contains at least 15% by weight of this copolymer, further acrylonitrile- Butadiene-styrene copolymer, acrylonitrile-butadiene-styrene-α-methylstyrene copolymer, acrylonitrile-
Styrene copolymer, acrylonitrile-α-methylstyrene copolymer, acrylonitrile-acrylic rubber-styrene copolymer, acrylonitrile-ethylene / propylene rubber-styrene copolymer, methyl methacrylate-
It may be a mixture of thermoplastic resins such as butadiene-styrene copolymer, aromatic polycarbonate, polybutylene terephthalate, polyethylene terephthalate, nylon-6, nylon-6.6, polyphenylene sulfide and polysulfone.

Here, the aromatic vinyl-unsaturated dicarboxylic acid imide copolymer and a method for producing the same will be described. Examples of the aromatic vinyl monomer constituting the copolymer include styrene monomers such as styrene, α-methylstyrene, vinyltoluene, t-butylstyrene, chlorostyrene and their substitution products. Among them, styrene is Particularly preferred. The aromatic vinyl-unsaturated dicarboxylic acid imide copolymer is an imide derivative obtained by copolymerizing an unsaturated dicarboxylic acid anhydride with an aromatic vinyl monomer and then reacting it with ammonia and / or a primary amine. Alternatively, an imide monomer such as maleimide, N-methylmaleimide, N-ethylmaleimide, N-cycloxylmaleimide, N-phenylmaleimide, or N-naphthylmaleimide may be directly copolymerized with an aromatic vinyl monomer. Good. However, as the method for producing these copolymers, the former method, that is, the method of copolymerizing an unsaturated dicarboxylic acid anhydride with an aromatic vinyl monomer and then imidizing the same, is more preferable in terms of copolymerizability and economy.

Examples of unsaturated dicarboxylic acid anhydrides include anhydrides such as maleic acid, itaconic acid, citraconic acid, and aconitic acid.
Maleic anhydride is especially preferred. Ammonia and primary amines used in the imidization reaction may be in an anhydrous or aqueous state, and examples of primary amines include alkylamines such as methylamine, ethylamine, propylamine, cyclohexylamine and the like. Aromatic amines such as chloro- or bromo-substituted alkylamines, aniline, tolylamine and naphthylamine, and chloro- or bromo-substituted aromatic amines are mentioned, and among them, aniline is particularly preferable.

When the imidization reaction of the copolymer of the aromatic vinyl monomer and the unsaturated dicarboxylic acid anhydride is carried out in a solution state or in a suspension state, it is preferable to use an ordinary reaction vessel, for example, an autoclave, etc. When carrying out in the state, an extruder equipped with a devolatilization device may be used. The temperature of the imidization reaction is about 80 to 350 ° C, preferably 100 to 300 ° C. If the temperature is lower than 80 ° C, the reaction rate is slow and the reaction takes a long time, which is not practical. On the other hand, when the temperature exceeds 350 ° C, the physical properties are deteriorated due to thermal decomposition of the polymer.

A catalyst may be used during the imidization reaction, and in that case, a tertiary amine such as triethylamine is preferably used.

The aromatic vinyl monomer residue in the aromatic vinyl-unsaturated dicarboxylic acid imide copolymer in the present invention is 35 to 75% by weight, and the content of the aromatic vinyl monomer residue is less than 35% by weight. If so, the moldability and dimensional stability characteristic of the aromatic vinyl compound are lost. If the unsaturated dicarboxylic acid imide derivative residue is less than 25% by weight, the heat resistance, hot water resistance and chemical resistance of the molded article will be insufficient. On the other hand, when the amount of the imide derivative residue exceeds 65% by weight, the mechanical strength of the molded product becomes insufficient and the moldability is significantly deteriorated.

The copolymer containing an aromatic vinyl monomer residue and an unsaturated dicarboxylic acid imide derivative residue used in the present invention contains 0 to 40% by weight of a rubber-like polymer and / or an aromatic vinyl monomer,
It may contain 0 to 40% by weight of a monomer residue copolymerizable with the unsaturated dicarboxylic acid anhydride and / or the unsaturated dicarboxylic acid imide derivative. As the rubber-like polymer, a butadiene polymer, a copolymer of a vinyl monomer copolymerizable with butadiene, an ethylene-propylene copolymer, an ethylene-propylene-diene copolymer, a block of butadiene and aromatic vinyl A copolymer, an acrylic acid ester polymer, a copolymer of an acrylic acid ester and a vinyl monomer copolymerizable therewith, and the like are used. As a monomer copolymerizable with an aromatic vinyl monomer, an unsaturated dicarboxylic acid anhydride and / or an unsaturated dicarboxylic acid imide derivative, a vinyl cyanide monomer such as acrylonitrile, methacrylonitrile or α-chloroacrylonitrile Acrylic acid ester monomers such as methyl acrylate, ethyl acrylate, butyl acrylate, methacrylic acid ester monomers such as methyl methacrylic acid and ethyl methacrylic acid, vinyl such as acrylic acid and methacrylic acid Examples include carboxylic acid monomers, acrylic acid amides, and methacrylic acid amides.

Examples of the solid lubricant used in the present invention include MoS ₂ , graphite, asbestos, fluorinated graphite, boron nitride and the like.

The amount of the solid lubricant used in the present invention is 0.1 part by weight in consideration of the effect of improving the friction and wear properties, relative to 100 parts by weight of the thermoplastic resin containing the aromatic vinyl-unsaturated dicarboxylic acid imide copolymer. 100 and above considering the mechanical strength of the resin
It is not more than 0.5 parts by weight, preferably 0.5 to 20 parts by weight.

Examples of the higher fatty acid used in the present invention include myristic acid, palmitic acid, stearic acid, montanic acid, oleic acid, erucic acid, linoleic acid, linolenic acid and the like.

The higher fatty acid ester is a compound obtained by condensation of a higher fatty acid and an alcohol. For example, regarding derivatives of stearic acid, polyoxyethylene distearate, glycerol monostearate, sorbitan stearate, propylene glycol monostearate, polyoxypropylene. Examples include glycol monostearate and polyoxyethylene sorbitan monostearate. Similarly, esters such as myristic acid, palmitic acid, montanic acid, oleic acid, erucic acid, linoleic acid, and linolenic acid are also included.

Examples of the higher fatty acid amide include palmitic acid amide,
Examples include stearic acid amide, oleic acid amide, linoleic acid amide, linolenic acid amide, and erucic acid amide.

In the composition for a sliding material of the present invention, the addition of a higher fatty acid, a higher fatty acid ester, a higher fatty acid amide or a silicone oil is observed to improve friction and wear characteristics, but an aromatic vinyl-unsaturated dicarboxylic acid imide copolymer is used. Considering adverse effects such as heat resistance of the resin, smoke emission during processing, and bleed-out on the surface of the molded product, the added amount is limited to 10 parts by weight or less, preferably 3 parts by weight or less, relative to 100 parts by weight of the thermoplastic resin contained. .

The composition for a sliding material of the present invention includes a stabilizer, a flame retardant, a plasticizer, a lubricant, an ultraviolet absorber, a coloring agent, talc, clay, silica, alumina, mica, a filler such as calcium carbonate,
A fluorine resin, an antistatic agent, etc. may be contained.

Since the composition for a sliding material of the present invention has remarkably excellent heat resistance as compared with a conventional composition for a sliding material, it can be used particularly advantageously in a field requiring a high degree of heat resistance.

Hereinafter, the present invention will be described with reference to examples, but the invention is not limited to the examples. In the examples,
All percentages are expressed by weight.

Experimental Example (1) 60 parts of styrene and 100 parts of methyl ethyl ketone were charged into an autoclave equipped with a stirrer, the system was replaced with nitrogen gas, the temperature was raised to 83 ° C, and 40 parts of maleic anhydride and benzoylper were added. 0.15 parts of oxide to 20 methyl ethyl ketone
A solution dissolved in 0 part was continuously added in 8 hours. The temperature was maintained at 83 ° C for a further 3 hours after the addition. A part of the viscous reaction liquid was sampled and the amount of unreacted monomer was quantified by gas chromatography.
It was 4.5% and 99% maleic anhydride. The non-polymeric solution obtained here contains 38 equivalents of aniline to maleic anhydride.
And 0.3 part of triethylamine were added, and the mixture was reacted at 140 ° C. for 7 hours. 200 parts of methyl ethyl ketone was added to the reaction solution, cooled to room temperature, poured into 1500 parts of vigorously stirred methanol, precipitated, separated and dried to obtain an imidized polymer. C-13
98% conversion of acid anhydride groups to imide groups by NMR analysis
It was. This imidized polymer contained 54.6 N-phenylmaleimide units as unsaturated dicarboxylic acid imide derivatives.
% Copolymer, and this was designated as Polymer A.

Experimental Example (2) Styrene 60 was added to the same Ooclave as in Experimental Example (1).
Parts, 100 parts of methyl ethyl ketone, and 10 parts of polybutadiene cut into small pieces were charged and stirred at room temperature for one day to dissolve the rubber, and then the system was replaced with nitrogen gas and the temperature was raised to 83 ° C. 40 parts maleic anhydride and benzoyl peroxide
A solution of 0.075 parts and 0.075 parts of azobisisobutyronitrile in 200 parts of methyl ethyl ketone was continuously added over 8 hours. After that, the same operation as in Experimental Example (1) was performed. Polymerization rate is styrene 96%, maleic anhydride 99
It was in%. This imidized polymer has four N-phenylmaleimide units as unsaturated dicarboxylic acid imide derivatives.
It was a copolymer containing 9.9% and was designated as Polymer B.

Experimental Example (3) Styrene 50 was added to the same autoclave as in Experimental Example (1).
And 10 parts of acrylonitrile were charged, and 0.15 parts of benzoyl peroxide in Experimental Example (1) was replaced with 0.15 parts of azobisisobutyronitrile, and 38 parts of aniline was replaced with 30 parts of aniline and 2.67 parts of methylamine. The same operation as (1) was performed. The polymerization rate was 98% styrene, 91% acrylonitrile, and 98% maleic anhydride. The conversion rate of acid anhydride groups to imide groups was 99%. This imidized polymer was a copolymer containing 52.5% of N-phenylmaleimide and N-methylmaleimide units as unsaturated dicarboxylic acid imide derivatives, and this was designated as Polymer C.

Experimental Example (4) Polybutadiene latex 143 parts (solid content 35%, weight average particle size 0.35μ, gel content 90%), potassium stearate 1 part, sodium formaldehyde sulfoxylate 0.1
Parts, tetrasodium ethylenediamine tetraacetate 0.03 parts, ferrous sulfate 0.003 parts and water 150 parts 50 parts
After heating to ℃, 50 parts of a monomer mixture consisting of 70% styrene and 30% acrylonitrile, 0.2 part of t-dodecyl mercaptan, 0.15 part of kyumen hydroperoxide are continuously added over 6 hours, and after addition, 65 ° C. The temperature was raised to 0 and polymerization was carried out for 2 hours. The polymerization rate was 98% styrene and 97% acrylonitrile by gas chromatography analysis. An antioxidant was added to the obtained latex, coagulated with calcium chloride, washed with water and dried to obtain a graft copolymer as a white powder. This was designated as Polymer D.

Example 1 46 parts of Polymer A obtained in Experimental Example (1), Experimental Example (2)
30 parts of the polymer B obtained in 4., 24 parts of ABS resin (GR-2000 manufactured by Denki Kagaku Kogyo Co., Ltd.), 10 parts of scaly natural graphite having an average particle size of 10 μ, and glycerol monostearate 0.5.
Part, octadecyl 3- (3,5-ditersiaributyl-4
After mixing 0.5 part of -hydroxyphenyl) -propionate with a Henschel mixer, it was extruded with an extruder with a vent to be pelletized, and a test piece was prepared with an injection molding machine. The physical properties of the molded article thus prepared were tested and the results are shown in Table 1.

Example 2 Instead of 10 parts of scale-like natural graphite having an average particle size of 10 μ,
Mixing, pelletization, and molding were carried out in the same manner as in Example 1 except that 10 parts of MoS _{2 having an} average particle size of 5 μm was used, and the physical property test was conducted. The results are shown in Table 1.

Example 3 60 parts of Polymer B obtained in Experimental Example (2), 40 parts of Polymer D obtained in Experimental Example (4), 5 parts of scaly natural graphite having an average particle size of 10 μ, and 0.5 part of stearic acid. The same procedure as in Example 1 was carried out except that The results are shown in Table 1.

Example 4 Instead of 5 parts of scale-like natural graphite having an average particle size of 10 μ,
The same procedure as in Example 3 was carried out except that 5 parts of MoS _{2 having an} average particle size of 5 μ was used. The results are shown in Table 1.

Example 5 70 parts of the polymer C obtained in the experimental example (3), 30 parts of the polymer D obtained in the experimental example (4), 5 parts of scaly natural graphite having an average particle size of 10 μ, and erucic acid amide 1 The same procedure as in Example 1 was carried out except that the parts were used. The results are shown in Table 1.

Example 6 70 parts of the polymer C obtained in the experimental example (3), 30 parts of the polymer D obtained in the experimental example (4), 1 part of boron nitride having an average particle size of 5 μ, and 0.5 part of silicon oil. The procedure was the same as in Example 1 except for the above. The results are shown in Table 1.

Comparative Example 1 From the mixture of Example 1, glycerol monostearate was removed, 1 part of tristearyl phosphite was added, and the same procedure as in Example 1 was carried out. The results are shown in Table 1.

Comparative Example 2 The procedure of Example 2 was repeated except that glycerol monostearate was removed from the mixture of Example 2 and 1 part of tristearyl phosphite was added. The results are shown in Table 1.

Comparative Example 3 The procedure of Example 3 was repeated except that the mixture of Example 3 was used, the amount of scaly natural graphite having an average particle size of 10 μ was adjusted to 10 parts, stearic acid was removed, and 1 part of tristearyl phosphite was added. The results are shown in Table 1.

Comparative Example 4 In the same manner as in Example 5, except that the mixture of Example 5 contained 10 parts of scaly natural graphite having an average particle size of 10 μ, erucic acid amide was removed, and 1 part of tristearyl phosphite was added. The results are shown in Table 1.

Comparative Example 5 From the mixture of Example 1, scaly natural graphite and glycerol monostearate were removed, 1 part of tristearyl phosphite was added, and the same procedure as in Example 1 was carried out. The results are shown in Table 1. .

Comparative Examples 6 to 8 Polystyrene (MW-2 manufactured by Denki Kagaku Kogyo Co., Ltd.), Nylon-6 (product of Toray Industries, Inc., CM1026), average particle size 10 μ
Scale natural graphite and MoS _{2 with an} average particle size of 5μ
Were mixed, pelletized and molded in the same manner as in Example 1 in the proportions shown in Table 1, and the respective physical property tests were carried out. The results are shown in Table 1.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display part C08K 5:10) (C08K 13/02 3:30 5:20) (56) References 59-27943 (JP, A) JP 58-71952 (JP, A) JP 50-100451 (JP, A) JP 50-50748 (JP, B1)

Claims (1)

[Claims] 1. A thermoplastic resin 100 containing 15% by weight or more of a copolymer containing 35 to 75% by weight of an aromatic vinyl monomer residue and 25 to 65% by weight of an unsaturated dicarboxylic acid imide derivative residue.
Parts by weight and solid lubricant 0.1 to 100 parts by weight and higher fatty acid,
A composition for a sliding material, which comprises at least 10 parts by weight (however, not 0 parts by weight) of at least one selected from the group of higher fatty acid esters, higher fatty acid amides and silicone oil.