JP2002038034A - Thermoplastic resin composition and resin molded product thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To achieve excellent sliding performance without using a lubricant while maintaining physical properties such as excellent mechanical properties of a thermoplastic resin, and to provide a good appearance. Provided are a thermoplastic resin composition and a resin molded product thereof. SOLUTION: The thermoplastic resin composition comprises (1) 50 to 99% by weight of a thermoplastic resin and (2) a graft copolymer 1 to 5%.
Contains 50% by weight. (1) Thermoplastic resins include polyolefin, polyoxymethylene, polyamide, aromatic polyester, polyphenylene sulfide, polyphenylene ether resin, and acrylonitrile-butadiene-
It is at least one selected from styrene copolymers. (2) The graft copolymer is an ultra-low density polyethylene polymer having a weight average molecular weight of 1,000 to 1,000.
000 segments and a weight average molecular weight of 1,000
~ 1,000,000 vinyl polymer segments.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermoplastic resin composition excellent in slidability without using a lubricant while maintaining mechanical properties, and a resin molded product thereof.

[0002]

2. Description of the Related Art Polyoxymethylene, polyamide, aromatic polyester and polyphenylene sulfide have excellent mechanical properties, electrical properties, moldability and dimensional accuracy of molded products, and also have excellent sliding properties. Widely used as sliding members such as gears.

[0003] In recent years, with the expansion of the field of use, even higher performance has been required for slidability, and various improvements have been made. For example, resin compositions for improving the sliding properties of polyoxymethylene and molded articles thereof are disclosed in JP-A-62-253650 and JP-A-63-253650.
Japanese Patent No. 37198 discloses a method in which a polyethylene resin having a specific MI (melt index) is added to polyoxymethylene so as to eliminate a decrease in friction coefficient and a squeal phenomenon during sliding.

Japanese Patent Application Laid-Open No. 63-33465 discloses a polyoxymethylene resin composition in which ultra-high-molecular-weight polyethylene fine powder is uniformly dispersed in polyoxymethylene to provide excellent moldability, friction resistance and abrasion resistance. Is disclosed.

Further, JP-A-2-138357 discloses that a graft copolymer of polyethylene and an acrylonitrile-styrene copolymer is dispersed in polyoxymethylene to provide excellent moldability, friction resistance and abrasion resistance. A polyoxymethylene resin composition is disclosed.

[0006]

However, Japanese Patent Application Laid-Open Nos. Sho 62-253650 and 63-37198 are known.
In the case where the slidability is improved by dispersing polyethylene in polyoxymethylene, as in the resin composition of JP-A No. 5-2, the mechanical strength is greatly reduced due to poor compatibility between polyethylene and polyoxymethylene. There was a problem. In addition, there has been a problem that the obtained molded article causes a delamination phenomenon and the appearance is deteriorated.

Further, when ultra-high molecular weight polyethylene fine powder is dispersed in polyoxymethylene as in the resin composition disclosed in JP-A-63-33465, the ultra-high molecular weight polyethylene is dispersed in large particles, so that the friction coefficient is increased. However, there is a problem that the effect cannot be sufficiently improved in the reduction of the temperature.

Further, in the resin composition disclosed in JP-A-2-138357, since the graft copolymer of polyethylene and acrylonitrile-styrene copolymer uses ordinary low density polyethylene (LDPE), the graft copolymer When synthesizing a coalesced product, there is a drawback that a large amount of a gel component is generated and the mechanical properties of the molded product are reduced.

Further, since the resin compositions described in these prior arts do not have sufficient sliding performance, they are actually used by adding a lubricant or the like. There was a problem in appearance and the like.

The present invention has been made by paying attention to the problems existing in the above prior art. Its purpose is to maintain excellent physical properties such as mechanical properties of thermoplastic resin, and to exhibit excellent sliding performance without using a lubricant, and to improve appearance. It is an object of the present invention to provide a thermoplastic resin composition and a resin molded product thereof.

[0011]

In order to achieve the above object, the thermoplastic resin composition of the first invention comprises (1) a polyolefin, polyoxymethylene, polyamide, aromatic polyester, polyphenylene sulfide, or polyphenylene ether resin. And acrylonitrile-butadiene-
50 to 99% by weight of at least one thermoplastic resin selected from the group of styrene copolymers, and (2) a density of 0.
In 92 g / cm ³ or less of very low density polyethylene polymer, segments 5-95% weight-average molecular weight of 1,000 to 1,000,000 and a weight average molecular weight which is formed from a vinyl monomer Is 1,000-1,000,000
95 to 5% by weight of a segment of the vinyl polymer which is 00
Wherein one segment contains 1 to 50% by weight of a multiphase structure graft copolymer in which the other segment forms a dispersed phase as particles having a particle diameter of 0.001 to 10 μm. It is.

[0012] The thermoplastic resin composition of the second invention comprises a first resin.
In the above invention, the vinyl polymer constituting the graft copolymer (2) is a styrene polymer. A thermoplastic resin composition according to a third aspect of the present invention is the thermoplastic resin composition according to the second aspect, wherein the styrene-based polymer is a copolymer obtained by copolymerizing styrene and a hydroxyl-containing vinyl-based monomer.

[0013] The thermoplastic resin composition of the fourth invention is characterized in that
In the above invention, the styrene-based polymer is a copolymer obtained by copolymerizing styrene and acrylonitrile.

According to a fifth aspect of the present invention, there is provided a resin molded product comprising:
The thermoplastic resin composition of any one of the inventions is formed into a predetermined shape.

[0015]

Embodiments of the present invention will be described below in detail. The thermoplastic resin composition includes (1) polyolefin, polyoxymethylene, polyamide, aromatic polyester, polyphenylene sulfide, polyphenylene ether resin, and acrylonitrile-butadiene-styrene copolymer (hereinafter abbreviated as ABS resin).
At least one thermoplastic resin 50 selected from the group of
To 99% by weight and (2) 1 to 50% by weight of a specific multiphase structure graft copolymer.

First, (1) the thermoplastic resin will be described. The polyolefin is a homopolymer of a non-polar olefin monomer or a copolymer formed from two or more non-polar olefin monomers. Specifically, ultra low density, low density, medium density, high density polyethylene, polypropylene,
It refers to homopolymers such as polybutene-1, poly-4-methylpentene, etc., ethylene-based polymers and propylene-based polymers, and particularly demands for improvement of propylene-based polymers are high. In addition, these polyolefins may be used as a mixture.

The propylene-based polymer is a crystalline polypropylene, and refers to a propylene homopolymer and a copolymer mainly composed of propylene and another α-olefin. It is desirable that these homopolymers or copolymers contain propylene in an amount of 75% by weight or more.

Specifically, for example, isotactic polypropylene, crystalline propylene-ethylene random copolymer, crystalline propylene-ethylene block copolymer,
A typical example is a crystalline propylene-butene-1 random copolymer. These propylene-based polymers can be used as a mixture. Further, other polymers can be mixed and used as long as the properties of the propylene-based polymer are not impaired.

The polyoxymethylene, which includes all known polyoxymethylenes, is obtained by, for example, polyaddition of formaldehyde or ring-opening polymerization of trioxane, a cyclic trimer of formaldehyde, or tetraoxane of a tetramer. It is something that can be done. For the purpose of improving the heat resistance, for example, a polyoxymethylene terminal which is acetylated with acetic anhydride or copolymerized with a cyclic ether to prevent thermal decomposition from the polymer terminal can be used.

The polyoxymethylene preferably has a weight-average molecular weight of 10,000-150,000.
Those of 5,000 to 70,000 are more preferred. If the weight average molecular weight is less than 10,000, sufficient mechanical properties cannot be obtained, and if it exceeds 150,000, moldability becomes poor, and both are not preferred.

Subsequently, as the polyamide, for example, nylon 6, nylon 6.6, nylon 6.10, nylon 6.12, nylon 11, nylon 12, nylon 4.
Aliphatic polyamides such as No. 6; aromatic polyamides such as polyhexamethylene diamine terephthalamide, polyhexamethylene diamine isophthalamide, and xylene group-containing polyamides; modified products thereof; and mixtures thereof. Particularly preferred polyamides are nylon 6, nylon 6.6, and the like.

The above-mentioned aromatic polyester is a polyester having an aromatic ring in a polymer chain unit, and mainly comprises an aromatic dicarboxylic acid (or an ester-forming derivative thereof) and a diol (or an ester-forming derivative thereof). It is a polymer or copolymer obtained by a condensation reaction as a component.

The aromatic dicarboxylic acids mentioned here include:
Terephthalic acid; isophthalic acid; phthalic acid; 2,6-naphthalenedicarboxylic acid; 1,5-naphthalenedicarboxylic acid; bis (p-carboxyphenyl) methane; anthracenedicarboxylic acid; 4,4'-diphenylcarboxylic acid;
4,4'-diphenyletherdicarboxylic acid; 1,2-
Bis (phenoxy) ethane-4,4'-dicarboxylic acid or an ester-forming derivative thereof may, for example, be mentioned.

The diol component is, for example, an aliphatic diol having 2 to 10 carbon atoms, that is, ethylene glycol.
1, propylene glycol; 1,4-butanediol;
Neopentyl glycol; 1,5-pentaneddiol;
1,6-hexanediol; decamethylene diglycol
Cyclohexanediol, molecular weight 400-6000
Polyethylene glycol; poly-1,3-propylene glycol; polytetramethylene glycol and mixtures thereof.

Preferred aromatic polyesters include, for example, polyethylene terephthalate; polypropylene terephthalate; polybutylene terephthalate; polyhexamethylene terephthalate; polyethylene-2,6-naphthalate; 1,2-bis (phenoxy)
Ethane-4,4'-dicarboxylate and the like. More preferred are polyethylene terephthalate and polybutylene terephthalate.

Polyphenylene sulfide is represented by the following chemical formula (1) and is generally obtained by reacting p-dichlorobenzene and sodium sulfide in a polar solvent such as N-methylpyrrolidone at 175 to 350 ° C. , But is not limited to this.

[0027]

Embedded image Next, the polyphenylene ether-based resin is represented by the following formula (2)
Is a polymer obtained by oxidatively polymerizing a phenol compound represented by the formula (1) with oxygen or an oxygen-containing gas using a coupling catalyst.

[0028]

Embedded image (Wherein, R _{11 to} R ₁₅ are selected from the group consisting of hydrogen, a halogen atom, a hydrocarbon group and a substituted hydrocarbon group;
One of them is always a hydrogen atom. Specific examples of R _{11 to} R ₁₅ in the above general formula include hydrogen, chlorine, fluorine, bromine, iodine, methyl, ethyl, propyl, butyl, chloroethyl, hydroxyethyl, phenylethyl, benzyl, hydroxymethyl, carboxyethyl, Examples include cyanoethyl, phenyl, methylphenyl, dimethylphenyl, ethylphenyl and the like.

Specific examples of the phenol compound of the general formula (2) include phenol, o-, m- or p-cresol, 2,6-, 2,5-, 2,4- or 3,5- Examples thereof include dimethylphenol, 2-methyl-6-ethylphenol, 2,3,5-, 2,3,6- and 2,4,6-trimethylphenol. Two or more of these phenol compounds can be used.

Further, a phenol compound other than the above general formula, for example, a copolymer of a dihydric phenol such as bisphenol A, resorcin, hydroquinone and the phenol compound of the above general formula may be used.

Further, homopolymers such as polystyrene, poly (α-methylstyrene) and poly (p-methylstyrene) or copolymers thereof, butadiene rubber, styrene-butadiene copolymer, ethylene-propylene copolymer High impact polystyrene, styrene-maleic anhydride copolymer, styrene-acrylonitrile copolymer, styrene-acrylonitrile-butadiene copolymer, styrene-methyl It is preferable to mix a styrene-based polymer such as a methacrylate copolymer in a range of 0 to 95% by weight based on the polyphenylene ether-based resin.

Next, the ABS resin is obtained by polymerizing two or more compounds selected from a vinyl cyanide compound, an aromatic vinyl compound and an unsaturated carboxylic acid alkyl ester compound in the presence of a conjugated diene rubber. Graft copolymer. In addition, if necessary, a copolymer obtained by polymerizing two or more compounds selected from a vinyl cyanide compound, an aromatic vinyl compound and an unsaturated carboxylic acid alkyl ester compound can be contained.

Examples of the conjugated diene rubber include polybutadiene, butadiene-styrene copolymer and butadiene-acrylonitrile copolymer. Acrylonitrile, methacrylonitrile, etc. as the vinyl cyanide compound, styrene, α-methylstyrene, vinyltoluene, dimethylstyrene, chlorostyrene, etc. as the aromatic vinyl compound, and methyl ester as the unsaturated carboxylic acid alkyl ester compound Acrylate,
Examples thereof include ethyl acrylate, butyl acrylate, methyl methacrylate, and hydroxyethyl acrylate.

Examples of the method for producing the ABS resin include an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, a bulk polymerization method, an emulsion-suspension polymerization method, and a bulk-suspension polymerization method. Among the above thermoplastic resins, polyoxymethylene is most preferable because it has excellent sliding performance. In addition, polyoxymethylene has a very high crystallinity, and is therefore preferable because it is often used in resins that are close to metals, such as gears and bearings where mechanical strength is required.

The polyolefin, polyoxymethylene, polyamide, aromatic polyester, polyphenylene sulfide, polyphenylene ether resin and AB
The proportion of at least one type of thermoplastic resin selected from the group of S resins (hereinafter, abbreviated as “resin to be modified”) in the thermoplastic resin composition is 50 to 99% by weight, preferably 60 to 95% by weight. %.

If the proportion is less than 50% by weight, the mechanical strength and heat resistance decrease. If it exceeds 99% by weight, the proportion of the specific multiphase graft copolymer described below decreases. Therefore, the effect of improving the sliding performance, which is the object of the present invention, is reduced.

Next, (2) the multiphase graft copolymer will be described. The graft copolymer has 5 to 95% by weight of an ultra-low density polyethylene polymer segment (hereinafter abbreviated as A segment) and 95 to 5% by weight of a vinyl polymer segment (hereinafter abbreviated as B segment). % By weight. The A segment usually becomes the main chain of the graft copolymer, and the B segment becomes the side chain of the graft copolymer. One segment has a multiphase structure in which the other segment forms a dispersed phase as particles having a particle diameter of 0.001 to 10 μm.

The polyethylene polymer constituting the A segment means a homopolymer of ethylene and a copolymer of ethylene as a main component and an α-olefin copolymerizable therewith. That is, in the polyethylene-based polymer, structural units derived from ethylene are preferably 50 to 10
0% by weight, more preferably 70% to 100% by weight, particularly preferably 80% to 100% by weight, having 3 to 3 carbon atoms.
20 to 50% by weight, more preferably 0 to 30% by weight of structural units derived from 20 α-olefins,
Particularly preferably, the amount is from 0 to 20% by weight.

The α-olefin having 3 to 20 carbon atoms includes propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, Examples thereof include 1-dodecene, 1-tetradecene, 1-hexadecene, 1-octadecene, and 1-eicosene.

The ultra-low density of the polyethylene polymer constituting the A segment means that the density is 0.92 g / cm ³ or less. This density is between 0.85 and 0.92
The range of g / cm ³ is more preferable.

In general, the higher the density of polyethylene, the lower the coefficient of kinetic friction tends to be. However, when polyethylene is used as a slidability modifier, it is hardly compatible with the resin to be modified, so that the amount of wear increases. It has the disadvantage of lacking performance persistence. Further, since high-density polyethylene is linear and has high crystallinity, even when a grafting reaction is performed, the reaction efficiency is low, and it is difficult to synthesize a modifier having good compatibility. For the above-mentioned reasons, the polyethylene polymer used in the present invention is inappropriate when the density exceeds 0.92 g / cm ³ , because the effect of improving the slidability is insufficient.

Conversely, when the density of the polyethylene is lowered, it is preferable from the viewpoint of the synthesis of the graft copolymer and the durability of the sliding performance, but it becomes difficult to obtain the ultra low density polyethylene polymer itself. Because of the tendency, the density is 0.
It is preferably at least 85 g / cm ³ .

The weight average molecular weight of the polyethylene polymer is 1,000 to 1,000,000, preferably 5,000 to 600,000. If the weight average molecular weight is less than 1,000, the durability of the effect of improving the slidability is insufficient, which is not suitable. Conversely, if the weight average molecular weight exceeds 1,000,000, the moldability is lowered, which is not suitable.

Next, the vinyl polymer forming the B segment of the graft copolymer is obtained by polymerizing one or more of the following vinyl monomers.
Specific examples of the vinyl monomer include (meth) acrylic esters such as hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, and 3-hydroxypropyl (meth) acrylate, acrylic acid, and methacryl. Acid, fumaric acid, maleic anhydride,
Itaconic acid, itaconic anhydride, bicyclo (2,2,1)
Α, β-unsaturated carboxylic acids such as -5-heptene-2,3-dicarboxylic acid and metal salts thereof, methyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-acrylate Ethylhexyl, methyl methacrylate, ethyl methacrylate, n-methacrylic acid
Butyl, α, β-unsaturated carboxylic acid esters such as isobutyl methacrylate, vinyl acetate, vinyl propionate,
Vinyl esters such as vinyl caproate, vinyl caprylate, vinyl laurate, vinyl stearate, and vinyl trifluoroacetate; unsaturated glycidyl group-containing monomers such as glycidyl acrylate, glycidyl methacrylate, and monoglycidyl itaconate; (Meth) alkyl ester derivatives such as aminoethyl (meth) acrylate, propylaminoethyl (meth) acrylate, dimethylaminoethyl methacrylate, aminopropyl (meth) acrylate, allylamine, methacrylamine,
Allylamine derivatives such as N, N-dimethylacrylamide, vinyl aromatic monomers, for example, styrene; nuclear-substituted styrene, for example, methylstyrene, dimethylstyrene, ethylstyrene, isopropylstyrene, chlorostyrene; α-substituted styrene, for example, α- Methylstyrene, α
Monomers such as ethylstyrene and (meth) acrylonitrile.

Among the vinyl polymers formed from these vinyl monomers, styrene is preferred because it has high compatibility with the resin to be modified, particularly polyoxymethylene or polyamide, and has a small amount of wear. Based polymer is preferred,
Particularly, styrene-hydroxyethyl (meth) acrylate copolymer, styrene-hydroxypropyl (meth) acrylate copolymer and styrene-acrylonitrile copolymer are most preferred.

The vinyl polymer has a weight average molecular weight of 1,000 to 1,000,000, preferably 5,000.
0 to 500,000. Weight average molecular weight of 1,000
If it is less than 0, the compatibility with the resin to be modified becomes poor, and the durability of the effect of improving the slidability is insufficient.
Conversely, if it exceeds 1,000,000, it is inappropriate for the same reason.

The proportion of the A segment in the multiphase graft copolymer is 5 to 95% by weight, preferably 20 to 95% by weight.
90% by weight. Therefore, the proportion of the B segment in the multiphase graft copolymer is 95 to 5% by weight, preferably 80 to 10% by weight.

If the proportion of the A segment is less than 5% by weight, the effect of improving the slidability is insufficient. On the other hand, if the content of the A segment exceeds 95% by weight, the compatibility with the slidability-improving resin decreases, and the mechanical properties and the continuity of the sliding performance decrease.

The multiphase graft copolymer referred to in the present invention is obtained by dispersing, in a matrix of A segment or B segment, B segment or A segment, which is a different segment, generally spherically and uniformly. Say.

The dispersed polymer has a particle size of 0.001.
10 to 10 μm, preferably 0.01 to 5 μm. When the dispersed particle diameter is less than 0.001 μm or more than 10 μm, the dispersibility is low, for example, the appearance of the obtained molded article is deteriorated or the mechanical properties are reduced.

The proportion of the multiphase graft copolymer in the thermoplastic resin composition is 1 to 50% by weight, preferably 5 to 40% by weight. When this proportion is less than 1% by weight, the proportion of the multi-phase structured graft copolymer is reduced, and the effect of improving the desired sliding performance is reduced.
If it exceeds, mechanical strength and heat resistance are reduced.

The grafting method for producing the graft copolymer having a multiphase structure may be any of generally known methods such as a chain transfer method and an ionizing radiation irradiation method. By the way. Because
This is because the grafting efficiency is high and secondary aggregation due to heat does not occur, so that the expression of performance is more effective and the production method is simple.

Next, the method for producing the multiphase graft copolymer will be specifically described. First, 100 parts by weight of an ultra-low density polyethylene polymer is suspended in water. Then, 1 to 400 parts by weight of at least one vinyl monomer is mixed with one or a mixture of two or more radically polymerizable organic peroxides represented by the following chemical formula (3) or (4). 0.1 to 20 parts by weight per 100 parts by weight of the vinyl monomer, 10
A polymerization initiator having a decomposition temperature of 40 to 90 ° C. for obtaining a half-life of time is 0.01 to 5 parts by weight based on 100 parts by weight of the total of the vinyl monomer and the radically polymerizable organic peroxide. And a mixed solution in which is dissolved.

Then, heating is carried out under the condition that decomposition of the polymerization initiator does not substantially occur, and the vinyl monomer, the radical polymerizable organic peroxide and the polymerization initiator are impregnated into the ultra-low density polyethylene polymer, When the impregnation reaches the initial 50% by weight or more, the temperature of the aqueous suspension is raised. Then, the vinyl monomer and the radical polymerizable organic peroxide are copolymerized in the ultra low density polyethylene polymer to obtain a graft precursor.

By kneading the grafting precursor while melting, a multiphase graft copolymer can be obtained. At this time, a polyethylene-based polymer or a vinyl-based polymer is mixed with the grafting precursor, and the mixture is kneaded under melting to obtain a multi-phase structure graft copolymer.

The radically polymerizable organic peroxide represented by the chemical formula (3) is the following compound.

[0057]

Embedded image In the formula, R ₁ is a hydrogen atom or an alkyl group having 1 to 2 carbon atoms,
R ₂ is a hydrogen atom or a methyl group; R ₃ and R ₄ are each an alkyl group having 1 to 4 carbon atoms; R ₅ is an alkyl group having 1 to 12 carbon atoms, phenyl group, alkyl-substituted phenyl group or 3 to 12 carbon atoms. Represents a cycloalkyl group. m is 1 or 2.

The radically polymerizable organic peroxide represented by the chemical formula (4) is the following compound.

[0059]

Embedded image In the formula, R ₆ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms,
R ₇ is a hydrogen atom or a methyl group; R ₈ and R ₉ are each an alkyl group having 1 to 4 carbon atoms; R ₁₀ is an alkyl group having 1 to 12 carbon atoms, a phenyl group, an alkyl-substituted phenyl group or a 3 to 12 carbon atoms. Represents a cycloalkyl group. n is 0, 1 or 2.

The melting and kneading temperature is 150 to 350 ° C.
Is preferred. When the temperature is lower than 150 ° C., the melting is incomplete, the melt viscosity is high, the mixing becomes insufficient, and phase separation or delamination appears in the molded product, which is not preferable. On the other hand, when the temperature exceeds 350 ° C., decomposition or gelation of the mixed resin occurs, which is not preferable.

The method of melting and mixing can be performed by a commonly used kneading machine such as a Banbury mixer, a pressure kneader, a kneading extruder, a twin screw extruder or a roll. Although the thermoplastic resin composition of the present invention and its molded product can exhibit excellent sliding performance without using a lubricant, there is no particular problem even when a lubricant is used in combination.

Usually used lubricants are added to improve the sliding performance of the resin, and include, for example, spindle oil, refrigerating machine oil, turbine oil, machine oil,
Mineral oils such as cylinder oil and gear oil, liquid paraffin, paraffin wax, hydrocarbons such as polyethylene wax, fatty acids such as lauric acid, myristic acid, palmitic acid and stearic acid, hexyl alcohol, octyl alcohol, cetyl alcohol, stearyl alcohol, etc. Other examples include alcohol and the like, and dimethylsiloxane and the like.

The proportion of the lubricant in the thermoplastic resin is usually not more than 20% by weight, preferably 0.1 to 15%.
%, More preferably 0.5 to 10% by weight.
In the present invention, within the scope not departing from the gist, furthermore, inorganic flame retardants such as magnesium hydroxide and aluminum hydroxide, halogen-based, organic flame retardants such as phosphorus-based, metal powder, antioxidant, ultraviolet ray inhibitor, lubricant, Dispersants, coupling agents, foaming agents, crosslinking agents, coloring agents, additives such as carbon black, and other polyolefin-based resins; aromatic polyesters, polyphenylene ethers, polycarbonates, polyoxymethylene, Engineering plastics such as polyphenylene sulfide; vinyl resins such as polystyrene, ABS resin and polyvinyl chloride may be added.

The functions and effects exerted by the above embodiment will be described below. -The polyethylene polymer constituting the A segment of the graft copolymer is excellent in the effect of improving the sliding performance.
The density of the polyethylene polymer is 0.92 g /
Since it has an ultra-low density of not more than ³ cm ³ , it has good compatibility with the thermoplastic resin as the resin to be modified, and has excellent durability of the sliding performance of the obtained molded article. For this reason, excellent sliding performance and its durability can be exhibited without using a low molecular weight lubricant.

Further, the reaction efficiency in obtaining the graft copolymer is improved, and the desired graft copolymer can be easily obtained. In addition, since the vinyl polymer constituting the B segment has good compatibility with the thermoplastic resin as the resin to be modified, it can maintain sliding performance and mechanical properties and prevent delamination. The appearance can be improved.

Further, since the degree of the sliding performance is determined by the mixing ratio of the multi-phase structured graft copolymer to be mixed, it is possible to easily produce many kinds and small quantities.

[0067]

The above embodiment will be described more specifically with reference to reference examples, examples and comparative examples.

Reference Example 1, Production of Multiphase Graft Copolymer Into a stainless steel autoclave having a volume of 5 liters, 2500 g of pure water was added, and 2.5 g of polyvinyl alcohol was further dissolved as a suspending agent. Was. Among them, 700 g of ultra-low density polyethylene "Naflex DFDB1088" (trade name, manufactured by Nippon Unicar Co., Ltd.) (hereinafter abbreviated as VLDPE) 700 g, styrene (abbreviated as St)
190 g and 100 g of 2-hydroxyethyl methacrylate (hereinafter abbreviated as HEMA) were added and dispersed by stirring. Next, the temperature of the autoclave was raised to 75 ° C., and the mixture was stirred for 2 hours to impregnate St and HEMA into VLDPE.

Next, the temperature of the autoclave was lowered to 70 ° C., 1.5 g of 3,5,5-trimethylhexanoyl peroxide as a polymerization initiator, and t-butylperoxymethacryloyloxyethyl as a radical polymerizable organic peroxide. 4 g of carbonate was dissolved in a mixed solution of 10 g of St, and this solution was poured into the autoclave and stirred. Then, the temperature of the autoclave was maintained at 70 ° C., and the temperature was maintained for 4 hours to complete the polymerization, followed by washing with water and drying to obtain a graft precursor. The St and HEMA copolymer of the grafted precursor was extracted with toluene, and the weight average molecular weight was measured by gel permeation chromatography (hereinafter abbreviated as GPC) to be 110,000.

Then, the grafted precursor was subjected to a Labo Plastomill single screw extruder (manufactured by Toyo Seiki Seisaku-sho, Ltd.) for 20 minutes.
It was extruded at 0 ° C. and subjected to a grafting reaction to obtain a multiphase graft copolymer.

When this was analyzed by pyrolysis gas chromatography, the weight ratio of each polymerized unit of polyethylene: styrene: 2-hydroxyethyl methacrylate was 70:20:10.

At this time, the graft efficiency of the styrene / 2-hydroxyethyl methacrylate polymer segment was 70% by weight. This multiphase structure graft copolymer is scanned with a scanning electron microscope “JEOL JSM T300”.
Observation by [JEOL Ltd.] revealed that a multiphase structure in which spherical resins having a particle diameter of 0.3 to 0.4 μm were uniformly dispersed was observed.

(Reference Examples 2 to 11) In the same manner as in Reference Example 1, the composition and the like were changed to the ratios shown in Tables 1 to 4 to synthesize a multiphase graft copolymer. The compositions and results are shown in Tables 1-4.
It was shown to.

REFERENCE EXAMPLE 12 A composition was prepared in the same manner as in Reference Example 1, except that t-butylperoxymethacryloyloxyethyl carbonate was not used. Table 4 shows the results.

[0075]

[Table 1]

[0076]

[Table 2]

[0077]

[Table 3]

[0078]

[Table 4] The abbreviations in the table represent the following. VLDPE: Polyethylene "Naflex DFDB10"
88 "[trade name, manufactured by Nippon Unicar Co., Ltd.] LDPE: polyethylene" Sumikacene G401 "[trade name, manufactured by Sumitomo Chemical Co., Ltd.] St: styrene AN: acrylonitrile HEMA: 2-hydroxyethyl methacrylate HPMA: hydroxypropyl methacrylate ( Example 1) Polyoxymethylene "Delrin 100"
[Trade name, manufactured by DuPont Co., Ltd.] 900 g and 100 g of the multi-phase structure graft copolymer (A) synthesized in Reference Example 1 were dry blended, and a twin screw extruder [PCM set at 210 ° C.
30, Ikegai Iron and Steel Co., Ltd.]. Next, 21
Inline screw injection molding machine set at 0 ° C [T
S-35-FV25, manufactured by Tabata Machine Industry Co., Ltd.], and the Izod impact value, deflection temperature under load, dynamic friction coefficient, specific wear amount, and appearance were measured. Table 5 shows the results.

The test method is as follows. (1) Izod impact value (with notch): JIS K7110 (2) Deflection temperature under load: JIS K7207 (3) Pin plate type friction test: Load 9.8 N (1 kg)
f), sliding speed 10 cm / sec, measuring time 1 hour, partner material, carbon steel S45C (4) Thrust type friction and wear test: JIS K7218, load 392 N (40 kgf), sliding speed 15 cm /
sec, partner material, carbon steel S45C (5) Appearance: Visually evaluated according to the following criteria.

；: Good appearance, Δ: slightly silvery,
×: With laminar peeling (Examples 2 to 18) The polyoxymethylene, the multi-phase structure graft copolymer, etc. were changed to another resin, and the mixture was melt-kneaded in the same manner as in Example 1, and each test piece was used. Created. The kneading compositions and test results are shown in Tables 5 to 10.

[0081]

[Table 5]

[0082]

[Table 6]

[0083]

[Table 7]

[0084]

[Table 8]

[0085]

[Table 9]

[0086]

[Table 10] The abbreviations in the table represent the following. PP: Polypropylene "J-Aroma PM671A"
[Trade name, manufactured by Nippon Polyolefin Co., Ltd.] POM: polyoxymethylene "Delrin 100" [trade name, manufactured by DuPont] PA: Nylon 6 "MC100L" [trade name, manufactured by Kanebo Co., Ltd.] PBT: poly Butylene terephthalate “UBEPBT1
000 "(trade name, manufactured by Ube Industries, Ltd.) PPS: Polyphenylene sulfide" Sumicon FM
MK104 "[trade name, manufactured by Sumitomo Bakelite Co., Ltd.] ABS: ABS resin" Styrac ABS121 "[trade name, manufactured by Asahi Kasei Corporation] PPE: polyphenylene ether resin" Noryl 731 "
J "(trade name, manufactured by Nippon GE Plastics Co., Ltd.) (Comparative Example 1) Using the multiphase structure graft copolymer synthesized in Reference Example 1, melted with polyoxymethylene in the same manner as in Example 1. After kneading, the same test as in Example 1 was performed. The results are shown in Table 11.

(Comparative Examples 2 to 6) Melt kneading was performed in the same manner as in Comparative Example 1 except that the type and amount of the multi-phase structure graft copolymer were changed, and respective test pieces were prepared. The kneading compositions and test results are shown in Tables 11 and 12.

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[Table 11]

[0089]

[Table 12] From the above results, the molded articles of the thermoplastic resin compositions of Examples 1 to 18 have excellent sliding performance without using a lubricant, and have good mechanical and thermal properties, and also have excellent appearance. I understood that. On the other hand, the resin compositions exemplified in Comparative Examples cannot exhibit any of the sliding performance, mechanical properties, and appearance. For example, in Comparative Example 5, since the graft copolymer polyethylene is not very low in density, the sliding performance is insufficient. In Comparative Example 6, the low-density polyethylene and the vinyl polymer were not graft-copolymerized, so that the compatibility with polyoxymethylene was poor.
As a result, there are disadvantages that the specific wear amount is large and the appearance is poor. Therefore, the thermoplastic resin compositions and molded articles of the respective examples can be used for a wide range of applications such as automobile parts, home electric appliance parts, and precision machine parts.

The technical ideas grasped from the above embodiment will be described below. The polyethylene polymer of the ultra-low density polyethylene polymer is a homopolymer of ethylene or a copolymer of ethylene as a main component and an α-olefin copolymerizable therewith. The thermoplastic resin composition according to any one of the above. With this configuration, the sliding performance of the obtained resin molded product can be reliably improved.

The ultra low density polyethylene polymer has a density of 0.85 to 0.92 g / cm ^3.
The thermoplastic resin composition according to any one of claims 1 to 4.
In such a configuration, an ultra-low density polyethylene-based polymer can be easily obtained while exhibiting the durability of sliding performance.

The thermoplastic resin composition according to any one of claims 1 to 4, wherein the thermoplastic resin (1) is polyoxymethylene. According to this configuration, the obtained resin molded product has excellent sliding performance and mechanical strength.

The thermoplastic resin composition according to any one of claims 1 to 4, wherein the polyolefin is a propylene-based polymer. With this configuration, it is possible to satisfy the demand for improvement shown in the effects of any of the first to fourth aspects of the invention.

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As described above, according to the present invention, the following effects can be obtained.

According to the thermoplastic resin composition of the first invention, excellent sliding performance can be exhibited without using a lubricant while maintaining physical properties such as excellent mechanical properties of the thermoplastic resin. And a good appearance can be obtained.

According to the thermoplastic resin composition of any one of the second to fourth inventions, in addition to the effects of the first invention, the compatibility with the resin to be modified, particularly polyoxymethylene or polyamide, is increased. , The amount of wear can be reduced.

According to the resin molded product of the fifth invention, the effect of the thermoplastic resin composition of any one of the first to fourth inventions can be effectively exerted. It can be used for a wide range of applications such as machine parts.

Continued on front page F-term (reference) 4F071 AA14 AA34 AA40 AA45 AA51 AA54 AA63 AA75 AA77 AA81 AA82 AH17 AH18 BC07 EA00 4J002 BB03W BB12W BB15W BB17W BN03X BN06X BN15W CB00W CF04W03 CB00W CF04W 03 CB00W CF04W BA25 BA27 BA29 BA31 BA32 BA34 BA35 DB03 DB15 EA03 FA02 GA09

Claims (5)

[Claims] 1. A thermoplastic resin of at least one selected from the group consisting of (1) polyolefin, polyoxymethylene, polyamide, aromatic polyester, polyphenylene sulfide, polyphenylene ether resin, and acrylonitrile-butadiene-styrene copolymer. (2) an ultra-low density polyethylene polymer having a density of 0.92 g / cm ³ or less and a weight average molecular weight of 1.0
5 to 95% by weight of a segment having a weight average molecular weight of 1,000 to 1,000,000 and a segment 95 to 5 of a vinyl polymer having a weight average molecular weight of 1,000 to 1,000,000 formed from a vinyl monomer. % Of a graft copolymer, wherein one segment forms a dispersed phase as particles having a particle diameter of 0.001 to 10 μm in the other segment and contains 1 to 50% by weight of a multiphase structure graft copolymer. Thermoplastic resin composition. 2. The thermoplastic resin composition according to claim 1, wherein the vinyl polymer constituting the graft copolymer (2) is a styrene polymer. 3. The thermoplastic resin composition according to claim 2, wherein the styrene polymer is a copolymer obtained by copolymerizing styrene and a hydroxyl group-containing vinyl monomer. 4. The thermoplastic resin composition according to claim 2, wherein the styrene-based polymer is a copolymer obtained by copolymerizing styrene and acrylonitrile. 5. A resin molded product obtained by molding the thermoplastic resin composition according to any one of claims 1 to 4 into a predetermined shape.