Sliding member

Abstract

To provide a sliding member which is formed into a composition of polyethylene and an ethylenic resin of a high molecular weight having a bimodal molecular weight, and thereby is excellent in workability, and has slidability and abrasion resistance equivalent to that of engineering plastic such as ultrahigh-molecular-weight polyethylene.SOLUTION: A sliding member is made of a polyethylene composition containing an ethylenic resin having HLMFR at a temperature of 190°C and a load of 21.6 kg of 0.01 to 100 g / 10 min, and a bimodal elution curve measured by GPC, and polyethylene having MFR at a temperature of 190°C and a load of 2.16 kg of 0.01 to 10 g / 10 min, and density of 930 to 980 kg / m3.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a specific molded member, and more specifically, to a sliding member which is excellent in processability, slidability, wear resistance, and slipperiness (low friction) and is therefore expected to be used as bearing parts, lining materials, rail materials, gears, artificial joints, sheet materials, film materials, plate materials, rod materials, and the like. [Background technology]

[0002] Polyethylene is a resin used in a wide range of applications, and in order to make it suitable for each application, technologies have been proposed to control the molecular weight distribution and composition by combining two or more resin components, thereby improving various physical properties and appearance. For example, an increase in higher molecular weight components improves mechanical strength but decreases moldability, while an increase in lower molecular weight components decreases mechanical strength but improves moldability.

[0003] As a method for combining two or more types of polyethylene components, there have been proposed a method in which each component is polymerized and then blended by melt kneading or dry blending, a method in which multi-stage polymerization is carried out continuously, a method in which two or more types of polyethylene components are simultaneously produced by adding a plurality of transition metal catalysts to a polymerization system, a method in which a combination of these is carried out, etc. In addition, a resin modifier has also been proposed (see, for example, Patent Document 1) that is blended with a target material to modify the physical properties, appearance, etc. of the target material.

[0004] In the drawing, spinning, blow molding, injection molding, inflation molding, and extrusion molding of polyethylene, materials with good moldability and physical properties are generally required. In recent years, there has been a demand for lighter weight and thinner walls to reduce costs, but at the same time, there is a demand for excellent mechanical strength.

[0005] Ultra-high molecular weight polyethylene, which has attracted attention in recent years (see, for example, Patent Documents 2 and 3), has an extremely high molecular weight equivalent to a viscosity average molecular weight (hereinafter sometimes referred to as Mv) of 1 million or more, and therefore has excellent impact resistance, self-lubrication, abrasion resistance, weather resistance, chemical resistance, dimensional stability, etc., and has high physical properties comparable to those of engineering plastics. For this reason, attempts have been made to apply it to uses such as sheets, films, high-strength fibers, sliding members, lining materials, line parts in the food industry, machine parts, artificial joints, sporting goods, microporous membranes, and separators by various molding methods.

[0006] However, because of its high molecular weight, ultra-high molecular weight polyethylene has extremely low fluidity when melted, and it is difficult to mold it by kneading and extrusion like ordinary polyethylene, which has a molecular weight in the range of several tens of thousands to about 300,000.Therefore, ultra-high molecular weight polyethylene is molded by various methods, such as direct sintering of the polymer powder obtained by polymerization, compression molding, molding using a ram extruder in which extrusion molding is performed while intermittently compressing, and extrusion molding into a sheet, film, or fiber shape in a state where it is uniformly mixed with a plasticizer, and in some cases, stretching it and then removing the solvent.

[0007] In order to improve the moldability of ultra-high molecular weight polyethylene and its mixability with other resins, a method of adding low molecular weight polyethylene has been proposed (see, for example, Patent Documents 4 and 5), and an ultra-high molecular weight polyethylene exhibiting a specific melting behavior has been proposed (see, for example, Patent Document 6). [Prior art documents] [Patent documents]

[0008] [Patent Document 1] JP 2017-179304 A [Patent Document 2] Patent No. 4868853 [Patent Document 3] Patent No. 6405888 [Patent Document 4] Patent No. 4173444 [Patent Document 5] Patent No. 7071966 [Patent Document 6] JP 2021-172716 A Summary of the Invention [Problem to be solved by the invention]

[0009] However, although the modified material proposed in Patent Document 1 was effective in improving processability to a certain extent, further improvements were required in terms of improving mechanical strength, particularly wear resistance and sliding properties.

[0010] Moreover, Patent Documents 2 and 3 merely propose ultra-high molecular weight polyethylene, and have problems with moldability. The proposals in Patent Documents 4 to 6 also only improve the processability of ultra-high molecular weight polyethylene, and still have problems with versatility.

[0011] Therefore, there has been a demand for a sliding member that has excellent mechanical properties, particularly excellent wear resistance and good sliding properties (low friction), without impairing the processability of general-purpose resins. [Means for solving the problem]

[0012] Means for Solving the Problems The present inventors conducted extensive research to solve the above problems and discovered that a composition of an ethylene-based resin and polyethylene having specific melting characteristics and molecular weight configuration can be used as a material having excellent processability and also having sliding properties, abrasion resistance and smooth sliding properties equal to or superior to those of engineering plastics such as ultra-high molecular weight polyethylene, thereby completing the present invention.

[0013] That is, the present invention relates to: (1) an ethylene-based resin having a high melt flow rate (HLMFR) of 0.01 to 100 g / 10 min at a temperature of 190° C. and a load of 21.6 kg in accordance with JIS 6922-2:1997 and a bimodal elution curve measured by gel permeation chromatography; and (2) an ethylene-based resin having a melt flow rate (MFR) of 0.01 to 10 g / 10 min at a temperature of 190° C. and a load of 2.16 kg in accordance with JIS 6922-2:1997 and a density of 930 to 980 kg / m as measured according to JIS K6922-1 (1997). 3 The present invention relates to a sliding member which is made of a polyethylene composition containing a polyethylene of the formula:

[0014] The present invention will be described in detail below.

[0015] The sliding member of the present invention comprises: (1) an ethylene-based resin (C) having a melt flow rate (hereinafter sometimes referred to as HLMFR) of 0.01 to 100 g / 10 min at a temperature of 190° C. and a load of 21.6 kg in accordance with JIS 6922-2:1997 and a bimodal elution curve measured by gel permeation chromatography (hereinafter sometimes referred to as GPC); and (2) an ethylene-based resin (C) having a melt flow rate (hereinafter sometimes referred to as MFR) of 0.01 to 10 g / 10 min at a temperature of 190° C. and a load of 2.16 kg in accordance with JIS 6922-2:1997 and a density of 930 to 980 kg / m as measured according to JIS K6922-1 (1997). 3The molded part is made of a polyethylene composition (e) containing a polyethylene (d) of the formula: The ethylene resin (c) may be a bimodal ethylene resin having a relatively high molecular weight that exhibits melting behavior and a bimodal elution curve measured by GPC that exhibits two peaks, and examples of the ethylene homopolymer and ethylene-α-olefin copolymer are available. Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, etc., and ethylene homopolymer is preferable because it is a member having excellent mechanical properties. Similarly, examples of the polyethylene (d) include ethylene homopolymer and ethylene-α-olefin copolymer, and examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, etc., and ethylene homopolymer is preferable because it is a sliding member having excellent mechanical properties, wear resistance, and slipperiness.

[0016] The ethylene-based resin (iii) has (1) an HLMFR of 0.01 to 100 g / 10 min and exhibits melt fluidity. If the HLMFR is less than 0.01 g / 10 min, the melt fluidity is poor and the processability is poor. On the other hand, if the HLMFR is more than 100 g / 10 min, the mechanical properties are poor.

[0017] The ethylene resin (iii) constituting the sliding member of the present invention is an ethylene polymer having a bimodal molecular weight distribution, and preferably contains a specific ultra-high molecular weight polyethylene component (i) as a specific component, since it results in a sliding member having an excellent balance between processability and mechanical properties. In this case, the bimodal molecular weight distribution is preferably one in which the elution curve measured by GPC has two peaks, and when the elution curve is expressed as a differential molecular weight distribution (x-axis: Log[M], y-axis: differential distribution value) and the peaks are divided into two normal distributions (normal distribution of ultra-high molecular weight polyethylene component (i) and normal distribution of polyethylene component (ii)) according to the following formula (i), it satisfies (2-1) to (2-3). f(x)=a×(1 / (2π(σ 2 )) (1 / 2) ) exp(-((x-μ) 2 ) / (2(σ 2 ))) Formula (i) (Here, a is the peak intensity, σ is the standard deviation, x is the variable, and μ is the mean.) (2-1) The ultra-high molecular weight polyethylene component (a) (hereinafter may be referred to as component (a)) represented as a high molecular weight peak component has a weight average molecular weight (hereinafter may be referred to as Mw) of 900,000 to 5,000,000 and a molecular weight distribution expressed as Mw / number average molecular weight (hereinafter may be referred to as Mn) of 2.0 to 5.0, (2-2) The polyethylene component (b) (hereinafter may be referred to as component (b)) represented as a low molecular weight peak component has an Mw of 10,000 to 500,000 and an Mw / Mn of 2.0 to 5.0, and (2-3) the component (a) / component (b) (weight ratio) is greater than 5 / 95 and less than 80 / 20, and it is particularly preferable that the component (a) / component (b) (weight ratio) is 10 / 90 to 50 / 50.

[0018] When the ethylene-based resin (III) is one in which the ultra-high molecular weight component (III) and the low molecular weight component (III) coexist in a specific ratio, the component (III) can be highly dispersed when blended with polyethylene, and the wear resistance and smooth sliding properties of the sliding member can be improved without impairing the appearance.

[0019] In order to provide a sliding member having an excellent balance between dispersibility in polyethylene and improvement in mechanical properties, the ethylene-based resin (C) preferably has (3) Mw / Mn, calculated as linear polyethylene as measured by GPC, of ​​4.0 or more and less than 50, and particularly preferably 4.0 or more and 30 or less.

[0020] In addition, since the components (A) and (B) are different from a simple blend in which each component is independently dispersed, the ethylene-based resin (C) is (4) measured using a differential scanning calorimeter (hereinafter sometimes referred to as DSC) by heating from 0°C to 230°C at a heating rate of 10°C / min (hereinafter sometimes referred to as 1st scan) at a crystal melting peak (hereinafter referred to as Tm 1 It is preferable that the peak intensity distribution is unimodal.

[0021] The ethylene-based resin (C) constituting the sliding member of the present invention is preferably one produced using a metallocene-based catalyst, since it is easy to control the molecular weight and molecular weight distribution and to produce an (ultra)high molecular weight. Among them, examples of a method for producing the ethylene-based resin (C) having both the component (A) and the component (B) include a method using a co-supported catalyst in which two or more kinds of metallocene complexes are supported on a carrier as a catalyst system, and a method using multi-stage polymerization of two or more stages.

[0022] The polymerization method of the ethylene-based resin (iii) may be, for example, a solution polymerization method, a bulk polymerization method, a gas phase polymerization method, a slurry polymerization method, etc., among which, the slurry polymerization method is preferable since it enables the production of an ethylene-based resin with a regular particle shape. The solvent used in the slurry polymerization method may be any organic solvent that is generally used, for example, benzene, toluene, xylene, pentane, hexane, heptane, etc., and liquefied gases such as isobutane and propane, and olefins such as 1-butene and 1-hexene can also be used as the solvent.

[0023] In addition, examples of the production catalyst used to produce the ethylene-based resin (iii) include, for example, in the case of multi-stage polymerization, a metallocene-based catalyst obtained from at least a transition metal compound (A-1), an organically modified clay modified with an aliphatic salt (B), and an organoaluminum compound (C); and, for example, in the case of a co-supported catalyst method, a metallocene-based catalyst obtained from at least a transition metal compound (A-1), a transition metal compound (A-2), an organically modified clay modified with an aliphatic salt (B), and an organoaluminum compound (C).

[0024] Examples of the transition metal compound (A-1) include a transition metal compound having a (substituted) cyclopentadienyl group and a (substituted) fluorenyl group, a transition metal compound having a (substituted) cyclopentadienyl group and a (substituted) indenyl group, and a transition metal compound having a (substituted) indenyl group and a (substituted) fluorenyl group. In this case, examples of the transition metal include zirconium and hafnium. Among these, a zirconium compound having a (substituted) cyclopentadienyl group and an amino group-substituted fluorenyl group and a hafnium compound having a (substituted) cyclopentadienyl group and an amino group-substituted fluorenyl group are preferred, as they enable efficient production of an ethylene-based resin suitable for use as a sliding member.

[0025] More specifically, for example, diphenylmethylene(1-indenyl)(9-fluorenyl)zirconium dichloride, diphenylmethylene(1-indenyl)(2,7-di-t-butyl-9-fluorenyl)zirconium dichloride, diphenylmethylene(4-phenyl-1-indenyl)(2,7-di-t-butyl-9-fluorenyl)zirconium dichloride, diphenylsilanediyl(cyclopentadienyl)(2-(dimethylamino)-9-fluorenyl)zirconium dichloride, diphenylsilanediyl(cyclopentadienyl)(2-(dimethylamino)-9-fluorenyl)zirconium dichloride, diphenylsilanediyl(cyclopentadienyl)(2-(dibenzylamino)-9-fluorenyl)zirconium dichloride, diphenylsilanediyl(cyclopentadienyl)(2,7-bis(dimethylamino)-9-fluorenyl)zirconium dichloride, diphenylsilanediyl(cyclopentadienyl)(2,7-bis(diethylamino)-9-fluorenyl)zirconium dichloride, diphenylsilanediyl(cyclopentadienyl)(2,7-bis(dibenzylamino)-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2-(dimethylamino)-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2-(diethylamino)-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2-(diisopropylamino)-9-fluorenyl)zirconium dichloride, Diphenylmethylene(cyclopentadienyl)(2-(dibenzylamino)-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2-(diethylamino)-7-ethyl-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2-(diisopropylamino)-7-ethyl-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2- Examples of zirconium compounds include (dibenzylamino)-7-ethyl-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2-(dimethylamino)-7-isopropyl-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2-(dimethylamino)-7-n-butyl-9-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2-(diisopropylamino)-7-t-butyl-9-fluorenyl)zirconium dichloride, and diphenylmethylene(cyclopentadienyl)(2-(dibenzylamino)-7-t-butyl-9-fluorenyl)zirconium dichloride; zirconium compounds in which the dichloro form of these compounds is replaced with a dimethyl form, a diethyl form, a dihydro form, a diphenyl form, or a dibenzyl form, and hafnium compounds in which the zirconium of these compounds is replaced with hafnium.

[0026] Examples of the transition metal compound (A-2) include a transition metal compound having a (substituted) cyclopentadienyl group and a (substituted) fluorenyl group, a transition metal compound having a (substituted) cyclopentadienyl group and a (substituted) indenyl group, and a transition metal compound having a (substituted) indenyl group and a (substituted) indenyl group.

[0027] More specifically, dimethylsilanediylbis(cyclopentadienyl)zirconium dichloride, diethylsilanediylbis(cyclopentadienyl)zirconium dichloride, dicyclohexylsilanediylbis(cyclopentadienyl)zirconium dichloride, dimethylsilanediyl[(cyclopentadienyl)(indenyl)]zirconium dichloride, diethylsilanediyl[(cyclopentadienyl)(indenyl)]zirconium dichloride, dicyclohexylsilanediyl[(cyclopentadienyl)(indenyl)]zirconium dichloride, diphenylsilanediyl[(cyclopentadienyl)(indenyl)]zirconium dichloride, dimethylsilanediyl[(cyclopentadienyl)(4,7-dimethylindenyl)]zirconium dichloride, di Ethylsilanediyl[(cyclopentadienyl)(4,7-dimethylindenyl)]zirconium dichloride, dicyclohexylsilanediyl[(cyclopentadienyl)(4,7-dimethylindenyl)]zirconium dichloride, diphenylsilanediyl[(cyclopentadienyl)(4,7-dimethylindenyl)]zirconium dichloride, dimethylsilanediyl[(cyclopentadienyl)(2,4,7-trimethylindenyl)]zirconium dichloride, diethylsilanediyl[(cyclopentadienyl)(2,4,7-trimethylindenyl)]zirconium dichloride, dicyclohexylsilanediyl[(cyclopentadienyl)(2,4,7-trimethylindenyl)]zirconium dichloride, diphenylsilanediyl[(cyclopentadienyl)(2,4,7-trimethylindenyl)]zirconium dichloride, bis(indenyl)zirconium dichloride, bis(cyclopentadienyl)zirconium dichloride, isopropylidene bis(indenyl)zirconium dichloride, (methyl)(phenyl)methylene bis(indenyl)zirconium dichloride, diphenylmethylene bis(indenyl)zirconium dichloride, ethylene bis(indenyl)zirconium dichloride, isopropylidene bis(2-methylindenyl)zirconium dichloride, diphenylmethylene bis(tetrahydroindenyl)zirconium dichloride, ethylene bis(tetrahydroindenyl)zirconium dichloride, isopropylidene(cyclopentadienyl)(fluorenyl)zirconium dichloride, (methyl)(phenyl)methylene(cyclopentadienyl)(fluorenyl)zirconium dichloride, diphenylmethylene Examples of zirconium compounds include (cyclopentadienyl)(fluorenyl)zirconium dichloride, ethylene(cyclopentadienyl)(fluorenyl)zirconium dichloride, isopropylidene(cyclopentadienyl)(2,7-di-t-butyl-fluorenyl)zirconium dichloride, (methyl)(phenyl)methylene(cyclopentadienyl)(2,7-di-t-butyl-fluorenyl)zirconium dichloride, diphenylmethylene(cyclopentadienyl)(2,7-di-t-butyl-fluorenyl)zirconium dichloride, and ethylene(cyclopentadienyl)(2,7-di-t-butyl-fluorenyl)zirconium dichloride; zirconium compounds in which the dichloro form of these compounds is replaced with a dimethyl form, a diethyl form, a dihydro form, a diphenyl form, or a dibenzyl form; and hafnium compounds in which the zirconium of these compounds is replaced with hafnium.

[0028] Examples of the organically modified clay (B) modified with an aliphatic salt include N,N-dimethyl-behenylamine hydrochloride, N-methyl-N-ethyl-behenylamine hydrochloride, N-methyl-Nn-propyl-behenylamine hydrochloride, N,N-dioleyl-methylamine hydrochloride, N,N-dimethyl-behenylamine hydrofluoride, N-methyl-N-ethyl-behenylamine hydrofluoride, N-methyl-Nn-propyl-behenylamine hydrofluoride, N,N-dioleyl-methylamine hydrofluoride, N,N-dimethyl-behenyl ... behenylamine hydrobromide, N-methyl-N-ethyl-behenylamine hydrobromide, N-methyl-Nn-propyl-behenylamine hydrobromide, N,N-dioleyl-methylamine hydrobromide, N,N-dimethyl-behenylamine hydroiodide, N-methyl-N-ethyl-behenylamine hydroiodide, N-methyl-Nn-propyl-behenylamine hydroiodide, N,N-dioleyl-methylamine hydroiodide, N,N-dimethyl-behenylamine sulfate, N-methyl-N-ethyl-behenylamine sulfate aliphatic amine salts such as N-methyl-Nn-propyl-behenylamine sulfate and N,N-dioleyl-methylamine sulfate; P,P-dimethyl-behenylphosphine hydrochloride, P,P-diethyl-behenylphosphine hydrochloride, P,P-dipropyl-behenylphosphine hydrochloride, P,P-dimethyl-behenylphosphine hydrofluoride, P,P-diethyl-behenylphosphine hydrofluoride, P,P-dipropyl-behenylphosphine hydrofluoride, P,P-dimethyl-behenylphosphine hydrobromide, P,P- Examples of the clay modified with an aliphatic salt include aliphatic phosphonium salts such as diethyl-behenylphosphine hydrobromide, P,P-dipropyl-behenylphosphine hydrobromide, P,P-dimethyl-behenylphosphine hydroiodide, P,P-diethyl-behenylphosphine hydroiodide, P,P-dipropyl-behenylphosphine hydroiodide, P,P-dimethyl-behenylphosphine sulfate, P,P-diethyl-behenylphosphine sulfate, and P,P-dipropyl-behenylphosphine sulfate.

[0029] In addition, as the clay compound constituting the organically modified clay (B), any clay compound belonging to the category of clay compounds may be used. Generally, a layer called a silicate layer formed by combining a tetrahedral sheet in which silica tetrahedra are continuous two-dimensionally and an octahedral sheet in which alumina octahedra, magnesia octahedra, etc. are continuous two-dimensionally in a ratio of 1:1 or 2:1 is stacked in multiple layers. Some of the Si in the silica tetrahedra is isomorphously substituted with Al, the Al in the alumina octahedra is substituted with Mg, the Mg in the magnesia octahedra is substituted with Li, etc., resulting in a deficiency of positive charge inside the layer, and the entire layer is negatively charged. To compensate for this negative charge, Na + or Ca 2+ and other cations are known to be present. As the clay compound, there are natural products or synthetic kaolinite, talc, smectite, vermiculite, mica, brittle mica, chlorite, etc., and these can be used. Among them, smectite is preferred because of its easy availability and ease of organic modification. Among smectites, hectorite or montmorillonite is even more preferred.

[0030] The organically modified clay (B) can be obtained by introducing the aliphatic salt between the layers of the clay compound to form an ion complex. When preparing the organically modified clay (B), it is preferable to select conditions of a clay compound concentration of 0.1 to 30% by weight and a treatment temperature of 0 to 150°C. The aliphatic salt may be prepared as a solid and dissolved in a solvent for use, or a solution of the aliphatic salt may be prepared by chemical reaction in a solvent and used as is. As for the reaction ratio of the clay compound and the aliphatic salt, it is preferable to use an equivalent or greater amount of aliphatic salt relative to the exchangeable cations of the clay compound. Examples of the treatment solvent that can be used include aliphatic hydrocarbons such as pentane, hexane, and heptane; aromatic hydrocarbons such as benzene and toluene; alcohols such as ethyl alcohol and methyl alcohol; ethers such as ethyl ether and n-butyl ether; halogenated hydrocarbons such as methylene chloride and chloroform; acetone; 1,4-dioxane; tetrahydrofuran; water, and the like. It is preferable to use alcohols or water alone or as one component of the solvent.

[0031] In addition, the particle size of the organically modified clay (B) constituting the production catalyst is not limited, and is preferably 1 to 100 μm, since it is excellent in efficiency during catalyst preparation and efficiency during ethylene-based resin production. There is also no limit to the method of adjusting the particle size, and large particles may be crushed to an appropriate particle size, small particles may be granulated to an appropriate particle size, or crushing and granulation may be combined. In addition, the particle size may be adjusted either on the clay before organic modification or on the organically modified clay after modification.

[0032] As the organoaluminum compound (C), any compound that belongs to the category called an organoaluminum compound can be used, and examples thereof include alkylaluminum such as trimethylaluminum, triethylaluminum, and triisobutylaluminum.

[0033] The proportions of the transition metal compounds (A-1) and (A-2) (hereinafter, the transition metal compounds (A-1) and (A-2) may be collectively referred to as component (A)), the organic modified clay (B) (hereinafter, also referred to as component (B)), and the organoaluminum compound (C) (hereinafter, also referred to as component (C)) that constitute the production catalyst are not subject to any restrictions so long as they can be used as a catalyst for producing polyethylene. In particular, in order to provide a production catalyst that can efficiently produce the ethylene-based resin (C), the molar ratio per metal atom of component (A) to component (C) is preferably in the range of component (A):component (C)=100:1 to 1:100,000, and more preferably in the range of 1:1 to 1:10,000. Furthermore, the weight ratio of component (A) to component (B) is preferably component (A):component (B)=10:1 to 1:10000, and more preferably in the range of 3:1 to 1:1000.

[0034] Regarding the preparation method of the production catalyst, any method may be used as long as it is possible to prepare a production catalyst containing the (A) component, the (B) component, and the (C) component, and for example, a method of mixing the (A), (B), and (C) components in a solvent inert to the respective components, or using the monomer to be polymerized as a solvent, can be mentioned. In addition, there is no restriction on the order in which these components are reacted, and there is no restriction on the temperature and time of this treatment. In addition, it is also possible to prepare a production catalyst using two or more kinds of each of the (A), (B), and (C) components.

[0035] The polymerization conditions such as polymerization temperature, polymerization time, polymerization pressure, and monomer concentration when producing the ethylene resin (iii) can be arbitrarily selected, and among them, it is preferable to carry out the polymerization at a polymerization temperature of 0 to 100°C, for a polymerization time of 10 seconds to 20 hours, and at a polymerization pressure of normal pressure to 100 MPa. It is also possible to adjust the molecular weight by using hydrogen or the like during the polymerization. The polymerization can be carried out by any method such as a batch method, a semi-continuous method, or a continuous method, and it is also possible to carry out the polymerization in two or more stages by changing the polymerization conditions. The polymer particles obtained after the polymerization is completed can be separated and recovered from the polymerization solvent by a conventionally known method, and dried to obtain the product.

[0036] The polyethylene (IV) constituting the sliding member of the present invention has an MFR of 0.01 to 10 g / 10 min and a density of 930 to 980 kg / m 3 Examples of such polyethylene include those mentioned above, and among them, high density polyethylene is preferable, and an example of such polyethylene is Nipolon Hard (trade name, manufactured by Tosoh Corporation). 3 On the other hand, if the MFR exceeds 20 g / 10 min, the abrasion resistance and mechanical properties will be poor.

[0037] The blending amount when blending into the polyethylene composition (E) constituting the sliding member of the present invention is arbitrary as long as excellent sliding properties and abrasion resistance as a sliding member are exhibited. In particular, in order to achieve an excellent balance between the abrasion resistance, good sliding properties and processability, it is preferable for the polyethylene composition (E) to contain 1 to 200 parts by weight of the ethylene resin (C) per 100 parts by weight of the polyethylene (D), and particularly preferably 10 to 100 parts by weight.

[0038] The polyethylene composition (e) constituting the sliding member of the present invention can be prepared by any method, and examples of the method include a method in which 1 to 200 parts by weight of ethylene-based resin (c) is mixed with 100 parts by weight of polyethylene (d), and further, if necessary, additives usually used in polyolefins, such as weather resistance stabilizers, heat resistance stabilizers, antistatic agents, antislip agents, antiblocking agents, antifogging agents, lubricants, pigments, nucleating agents, plasticizers, antiaging agents, antioxidants, UV absorbers, neutralizing agents, surfactants, slip agents, and inorganic or organic fillers, and then mixed and kneaded by a kneading machine or the like. The conditions for this step are not limited as long as they allow the polyethylene composition (e), and examples of the method include a method in which the ethylene-based resin (c) and polyethylene (d), and optionally other additives, are heated, melted, and kneaded at a temperature in the range of 190°C to 250°C for about 20 to 30 seconds using a single-screw or twin-screw melt kneader or the like, and further cut into pellets to be used as a molding material for compression, extrusion, etc.

[0039] The sliding member of the present invention can be prepared by any method, for example, a method in which the above-mentioned polyethylene composition (e) is prepared and then molded into a sliding member, or a method in which polyethylene (d), an ethylene-based resin (c) and other additives are blended and molded as is by extrusion molding, etc. Also, various molding methods such as compression molding, extrusion molding such as ram extrusion, injection molding, blow molding and the like can be used to make various sliding members.

[0040] Since the sliding member of the present invention is expected to have high wear resistance because the ethylene-based resin (c) and polyethylene (d), which have a relatively high molecular weight, are more uniformly dispersed, and since it exhibits high durability with little deformation even under high load and high speed environments, the limit PV value measured by a ring-on-disk test is preferably 350 kPa·m / s or more, and particularly preferably 400 kPa·m / s or more. Here, the limit PV value can be measured, for example, by a ring-on-disk test at 25°C, a speed (V) of 30 m / min, and a load (P) increased in increments of 20 N.

[0041] In addition, since this prevents the generation of abnormal noise due to friction in the usage environment and provides excellent quietness, and also prevents melting and seizing of components and provides excellent safety and durability, the kinetic friction coefficient is preferably less than 0.20, and more preferably less than 0.15. Here, the kinetic friction coefficient can be, for example, the average value of the kinetic friction coefficient calculated from the following (ii) when the torque is stable for about 10 minutes from the start 30 minutes in a ring-on-disk test at 25°C, a speed of 30 m / min, and a load of 0.5 MPa. Dynamic friction coefficient (μ)=T(N m) / (W(N)×Rm(m)) (ii) (Here, T is the torque, W is the normal load, and Rm is the mean ring radius.) Furthermore, since the sliding member of the present invention has excellent abrasion resistance against roughness, for example, when the surface of the mating material is rough and in an environment where sand and gravel collide, when a reciprocating flat abrasion test is carried out under conditions of abrasive paper CP320 (manufactured by Sankyo Rikagaku Co., Ltd.), a pressing force of 3.9 N±0.1 N, and a double stroke count of 400 ds, the mass loss before and after the test is preferably less than 10 mg, and more preferably less than 5 mg.

[0042] The sliding member of the present invention has an excellent balance between processability, sliding property, and abrasion resistance, and can be used as various members and structural materials, such as lining materials, sheet materials, pipes, bars, film materials, rails, line parts in the food industry, machine parts such as gears, artificial joint parts, and sporting goods. Effect of the Invention

[0043] This sliding component has excellent processability and is expected to have a thinner wall and longer life with sliding properties and abrasion resistance comparable to engineering plastics, and is expected to be used in a variety of applications. EXAMPLES

[0044] The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to these examples as long as the gist of the present invention is not exceeded.

[0045] Unless otherwise specified, the reagents used were either commercially available or synthesized according to known methods.

[0046] The organically modified clay was pulverized using a jet mill (product name: CO-JET SYSTEM α MARK III, manufactured by Seishin Enterprise Co., Ltd.), and the particle size after pulverization was measured using a Microtrack particle size distribution measuring device (product name: MT3000, manufactured by Nikkiso Co., Ltd.) using ethanol as a dispersant.

[0047] The preparation of the catalyst for production, the production of the ethylene resin, and the purification of the solvent were all carried out under an inert gas atmosphere. The hexane solution (20 wt%) of triisobutylaluminum manufactured by Toso Finechem Co., Ltd. was used.

[0048] Furthermore, various physical properties of the ethylene resin and polyethylene were measured by the methods shown below.

[0049] ~Measurement of intrinsic viscosity ([η])~ The measurements were performed using an Ubbelohde viscometer, decahydronaphthalene as a solvent, at 135° C., and an ethylene resin concentration of 0.005 wt %.

[0050] ~Measurement of weight average molecular weight (Mw) and number average molecular weight (Mn)~ Measurements were performed using an ultra-high temperature GPC (Senshu Scientific, product name SSC-7110) equipped with a column (Tosoh, product name TSKgel GMHHR-H(S)HT) with 1-chloronaphthalene as the eluent at a column temperature of 210°C, a sample concentration of 0.5mg / ml, and an injection volume of 0.2ml. The molecular weight calibration curve was calibrated using a standard polystyrene sample, and Mw and Mn were converted to linear polyethylene.

[0051] ~MFR measurement~ The melt flow rate was measured at a temperature of 190° C. under a load of 2.16 kg in accordance with JIS 6922-2:1997.

[0052] ~Measurement of HLMFR~ The melt flow rate was measured at a temperature of 190° C. under a load of 21.6 kg in accordance with JIS 6922-2:1997.

[0053] ~Thermal melting measurement of ethylene resin~ Using a DSC (manufactured by SII NanoTechnology, Inc., product name: DSC6220), the temperature was raised from 0°C to 230°C at a heating rate of 10°C / min (1st scan), and the crystal melting peak (Tm 1 ), heat of fusion (ΔH 1 ) measurements were carried out.

[0054] Furthermore, various physical properties of the members were measured by the methods shown below.

[0055] ~Wear time measurement~ A ring-on-disk test was performed using a multi-function friction and wear tester (manufactured by Bruker, (product name) UMT TriboLab). The measurement conditions were 25°C, speed 30 m / min, load 0.5 MPa, mating material S45C, and maximum test time 360 ​​minutes, and the time (min) until a wear depth of 1.5 mm was measured.

[0056] ~Measurement of limit PV value~ A ring-on-disk test was carried out using a multi-function friction and wear tester (manufactured by Bruker, (product name) UMT TriboLab). The measurement conditions were 25°C, counter material S45C, speed (V) constant at 30 m / min, load (P) was increased in 20 N increments every 30 minutes, and the load at which the friction temperature rose sharply and the sample began to melt was measured, and the limit PV value (kPa m / s) was measured.

[0057] A limiting PV value of 350 kPa·m / s or more was determined to be particularly excellent in durability under high load and friction.

[0058] ~Dynamic friction coefficient~ A ring-on-disk test was conducted using a multi-function friction and wear tester (manufactured by Bruker, (product name) UMT TriboLab). The measurement conditions were 25°C, speed 30 m / min, load 0.5 MPa, and counter material S45C. The average value of the dynamic friction coefficient was calculated from the formula (friction coefficient (μ) = T (N m) / (W (N) × Rm (m)) (where T is the torque, W is the normal load, and Rm is the average radius of the ring) in the range where torque fluctuation was small and stable for about 10 minutes from 30 minutes after the start of the test.

[0059] When the dynamic friction coefficient is 0.20 or more, it is determined that the friction-induced abnormal noise generated in the usage environment is minimal, the product is excellent in quietness, durability, and slipperiness.

[0060] ~Reciprocating motion flat surface wear test~ The test was carried out using a Suga abrasion tester NUS-ISO-3 (manufactured by Suga Test Instruments Co., Ltd.) with abrasive paper CP320 (manufactured by Sankyo Rikagaku Co., Ltd.) under conditions of a pressing force of 3.9 N ± 0.1 N and a double stroke count of 400 ds, and the abrasion resistance was evaluated based on the mass loss (mg) before and after the test.

[0061] When the mass loss was 10 mg or less, it was determined that the abrasion resistance was particularly excellent.

[0062] Preparation Example 1 (1) Preparation of organically modified clay 300 ml of industrial alcohol (manufactured by Japan Alcohol Sales Co., Ltd., (trade name) Ekinen F-3) and 300 ml of distilled water were placed in a 1-liter flask, 15.0 g of concentrated hydrochloric acid and 42.4 g (120 mmol) of dimethylbehenylamine (manufactured by Lion Specialty Chemicals, (trade name) Lipomin DM22D) were added, and the mixture was heated to 45°C to disperse 100 g of synthetic hectorite (manufactured by BYK Additives Limited, (trade name) Laponite RDS), and then the mixture was heated to 60°C and stirred for 1 hour while maintaining the temperature. After filtering the slurry, it was washed twice with 600 ml of hot water at 60°C and dried in a dryer at 85°C for 12 hours to obtain 125 g of organically modified clay. This organically modified clay was pulverized in a jet mill to a median diameter of 10 μm.

[0063] (2) Preparation of catalyst suspension for production After replacing the air in a 300 ml flask equipped with a thermometer and a reflux condenser with nitrogen, 25.0 g of the organically modified clay obtained in (1) and 108 ml of hexane were added, followed by 0.669 g of diphenylmethylene(cyclopentadienyl)(2,7-di-t-butyl-9-fluorenyl)zirconium dichloride and 142 ml of a hexane solution of 20 wt% triisobutylaluminum, and the mixture was stirred at 60°C for 3 hours. After cooling to 45°C, the supernatant was removed and washed twice with 200 ml of hexane, and then 200 ml of hexane was added to obtain a suspension of a catalyst for production (solid weight content: 12.5 wt%).

[0064] Preparation Example 2 (1) Preparation of organically modified clay The same procedure as in Preparation Example 1 was followed.

[0065] (2) Preparation of catalyst suspension for production After replacing the air in a 300 ml flask equipped with a thermometer and reflux condenser with nitrogen, 25.0 g of the organically modified clay obtained in (1) and 108 ml of hexane were added, followed by 0.628 g of diphenylmethylene(cyclopentadienyl)(2-diethylamino-9-fluorenyl)zirconium dichloride and 142 ml of a hexane solution of 20 wt% triisobutylaluminum, and the mixture was stirred at 60°C for 3 hours. After cooling to 45°C, the supernatant was removed and washed twice with 200 ml of hexane, and then 200 ml of hexane was added to obtain a suspension of a catalyst for production (solid weight content: 12.5 wt%).

[0066] Preparation Example 3 (1) Preparation of organically modified clay In a 1-liter flask, 300 ml of industrial alcohol (product name Ekinen F-3, manufactured by Japan Alcohol Sales Co., Ltd.) and 300 ml of distilled water were added, and 15.0 g of concentrated hydrochloric acid and dioleylmethylamine ((C 18 H 35 ) 2 (CH 3 )N, 63.7g (120mmol) of (trade name) Lipomin MO (manufactured by Lion Specialty Chemicals Co., Ltd.) was added and heated to 45℃, after which 100g of synthetic hectorite (trade name Laponite RD, manufactured by BYK) was dispersed, and the temperature was raised to 60℃ and stirred for 1 hour while maintaining the temperature. After filtering the slurry, it was washed twice with 600ml of water at 60℃ and dried in a dryer at 85℃ for 12 hours to obtain 130g of organically modified clay. This organically modified clay was pulverized in a jet mill to a median diameter of 15μm.

[0067] (2) Preparation of catalyst suspension for production After replacing the air in a 300 ml flask equipped with a thermometer and a reflux condenser with nitrogen, 25.0 g of the organically modified clay obtained in (1) and 108 ml of hexane were added, followed by the addition of 0.392 g (1 mmol) of bis(indenyl)zirconium dichloride and 142 ml of a 20 wt% hexane solution of triisobutylaluminum, and stirring for 3 hours at 60°C. After cooling to room temperature, the supernatant was removed and washed twice with 220 ml of hexane, followed by the addition of 220 ml of hexane to obtain a suspension of a catalyst for production (solid weight content: 12.0 wt%).

[0068] Manufacturing Example 1 As described below, a bimodal polyethylene ethylene resin (III-1) was produced by two-stage polymerization in which the polymerization of component (III-1) was successively carried out after the polymerization of component (III-1). The ethylene resin (III-1) had an HLMFR of 3.1 g / 10 min and an [η] of 4.1 dl / g.

[0069] Manufacturing of component (A-1) In a 10-liter autoclave, 6 liters of hexane, 5.5 ml of a hexane solution of 20 wt% triisobutylaluminum, and 2.50 g (equivalent to 310 mg of solid content) of the suspension of the production catalyst obtained in Preparation Example 1 were added, and the temperature was raised to 70°C. Ethylene was continuously fed so that the ethylene partial pressure could be maintained at 0.80 MPa, and slurry polymerization was carried out for 1 hour. During the polymerization, 200 g of ethylene was consumed in terms of polyethylene, and the [η] of component (A-1) calculated from the relationship with the hydrogen concentration in the system during the polymerization reaction was 10 dl / g.

[0070] Manufacture of component (B-1) and ethylene resin (C-1) After polymerizing component (a-1), ethylene was continuously fed so that the ethylene partial pressure was maintained at 0.87MPa at 60°C, and hydrogen was intermittently added so that the hydrogen concentration in the gas phase of the autoclave was 4500ppm, and slurry polymerization was carried out for 4 hours to polymerize component (b-1), thereby producing ethylene-based resin (c-1), which is an ethylene homopolymer. During the polymerization, 800g of ethylene was consumed in terms of polyethylene, and the [η] of component (b-1) calculated from the relationship with the hydrogen concentration in the system during the polymerization reaction was 2.0dl / g.

[0071] Manufacturing Example 2 As described below, an ethylene resin (III-2), which is a bimodal polyethylene, was produced by two-stage polymerization in which the polymerization of component (III-2) was successively carried out after the polymerization of component (III-2). The ethylene polymer (III-2) had an HLMFR of 0.23 g / 10 min and an [η] of 6.6 dl / g.

[0072] Manufacturing of component (A-2) In a 10-liter autoclave, 6 liters of hexane, 5.5 ml of a hexane solution of 20 wt% triisobutylaluminum, and 2.50 g (equivalent to 310 mg of solid content) of the suspension of the production catalyst obtained in Preparation Example 1 were added, and the temperature was raised to 70°C. Ethylene was continuously fed so that the ethylene partial pressure could be maintained at 0.80 MPa, and slurry polymerization was carried out for 2.5 hours. During the polymerization, 500 g of ethylene was consumed in terms of polyethylene, and the [η] of component (A-2) calculated from the relationship with the hydrogen concentration in the system during the polymerization reaction was 10 dl / g.

[0073] Manufacture of component (B-2) and ethylene resin (B-2) After polymerization of component (a-2), ethylene was continuously fed so that the ethylene partial pressure was maintained at 0.87MPa at 60°C, and hydrogen was intermittently added so that the hydrogen concentration in the gas phase of the autoclave was 4500ppm, and slurry polymerization was carried out for 2.5 hours to polymerize component (b-2), thereby producing ethylene-based resin (c-2), which is an ethylene homopolymer. During the polymerization, 500g of ethylene was consumed in terms of polyethylene, and the [η] of component (b-2) calculated from the relationship with the hydrogen concentration in the system during the polymerization reaction was 2.0dl / g.

[0074] Production Example 3 As described below, a bimodal polyethylene ethylene-based resin (III-3) was produced by two-stage polymerization in which the polymerization of component (III-3) was successively carried out after the polymerization of component (III-3). The ethylene-based resin (III-3) had an HLMFR of 0.08 g / 10 min and an [η] of 7.5 dl / g.

[0075] Manufacturing of component (A-3) 6 liters of hexane, 5.5 ml of a hexane solution of 20 wt% triisobutylaluminum, and 2.50 g (equivalent to 310 mg of solid content) of the suspension of the production catalyst obtained in Preparation Example 2 were added to a 10-liter autoclave, and the temperature was raised to 60°C. Ethylene was continuously fed so that the ethylene partial pressure could be maintained at 0.80 MPa, and slurry polymerization was carried out for 2 hours. During the polymerization, 200 g of ethylene was consumed in terms of polyethylene, and the [η] of component (A-3) calculated from the relationship with the hydrogen concentration in the system during the polymerization reaction was 22 dl / g.

[0076] Manufacture of component (B-3) and ethylene resin (B-3) After polymerization of component (a-3), ethylene was continuously fed so that the ethylene partial pressure was maintained at 0.50MPa at 60°C, and hydrogen was intermittently added so that the hydrogen concentration in the gas phase of the autoclave was 4500ppm, and slurry polymerization was carried out for 8 hours to polymerize component (b-3), thereby producing ethylene-based resin (c-3), which is an ethylene homopolymer. During the polymerization, 800g of ethylene was consumed in terms of polyethylene, and the [η] of component (b-3) calculated from the relationship with the hydrogen concentration in the system during the polymerization reaction was 2.0dl / g.

[0077] Production Example 4 A high density polyethylene (H-4) was produced as follows.

[0078] Manufacturing of component (Ha-4) 6 liters of hexane, 5.5 ml of a hexane solution of 20 wt% triisobutylaluminum, and 2.50 g (equivalent to 310 mg of solid content) of the suspension of the production catalyst obtained in Preparation Example 3 were added to a 10-liter autoclave, and the temperature was raised to 60°C. Ethylene was continuously fed so that the ethylene partial pressure could be maintained at 0.8 MPa, and hydrogen was intermittently added so that the hydrogen concentration in the gas phase of the autoclave was 2500 ppm, and slurry polymerization was carried out for 1 hour. 100 g of ethylene was consumed in terms of polyethylene during the polymerization, and the MFR of the obtained (Ha-4) was 20 g / 10 min.

[0079] [Table 1]

[0080] Example 1 250 g of the ethylene-based resin (H-1) obtained in Production Example 1, polyethylene (manufactured by Tosoh Corporation, (product name) Nipolon Hard 5110 (MFR = 0.9 g / 10 min, density = 961 kg / m 3), 750 g of which may be referred to as NH5110 below) were dry-blended in a pellet state, and then melt-kneaded using a single-screw extruder (manufactured by Toyo Seiki Seisakusho, (trade name) Labo Plastomill Single-screw Extruder D2025N) at 200°C, 50 rpm, and a discharge rate of 1.3 kg / h to obtain composition (E-1). The MFR of composition (E-1) was 0.38 g / 10 min.

[0081] 40 g of the obtained composition (E-1) was press-molded at 180°C and 10 MPa for 10 minutes using a precision heating and pressing device (manufactured by Shinto Kogyo Co., Ltd.), and then cooled to 40°C at 10 MPa to obtain a sheet-like sliding member having a thickness of 5.0 mm. A test sample for ring-on-disk testing was prepared by cutting a piece of 30 mm x 30 mm x 3.5 mm from the obtained sliding member.

[0082] The obtained composition (E-1) was press molded at 180°C and 10 MPa for 10 minutes using a high-temperature 50t automatic press (manufactured by Shinto Metal Industries Co., Ltd.), and then cooled at 25°C and 10 MPa for 5 minutes to obtain a sliding member of 150 mm x 150 mm x 0.5 mm. The obtained sliding member was used as a test sample for a reciprocating flat wear test.

[0083] The obtained sliding member exhibited a limit PV value of 470 kPa·m / s, a dynamic friction coefficient of 0.14, and a mass loss of 5.2 mg in a reciprocating flat wear test.

[0084] Example 2 100g of the ethylene resin (H-2) obtained in Production Example 2, 900g of polyethylene (NH5110) and 2g of an antioxidant (manufactured by BASF, (trade name) Irganox B225) were dry-blended in powder form, and then melt-kneaded using a twin-screw extruder (manufactured by Toyo Seiki Seisakusho, (trade name) Labo Plastomill Parallel Twin-screw Extruder 2D25S) at 220°C, 30 rpm and a discharge rate of 0.8 kg / h to obtain a composition (H-2). The MFR of the composition (H-2) was 0.36 g / 10 min.

[0085] The obtained composition (E-2) was subjected to the same method as in Example 1 to obtain a sliding member.

[0086] The obtained sliding member exhibited a limit PV value of 400 kPa·m / s, a dynamic friction coefficient of 0.17, and a mass loss of 5.4 mg in a reciprocating flat wear test.

[0087] Example 3 A composition (E-3) was obtained in the same manner as in Example 2, except that the ethylene resin (E-3) obtained in Production Example 3 was 250 g and the polyethylene was 750 g. A sliding member was obtained in the same manner as in Example 1.

[0088] The obtained sliding member exhibited a limit PV value of 470 kPa·m / s, a dynamic friction coefficient of 0.15, and a mass loss of 5.2 mg in a reciprocating flat wear test.

[0089] Example 4 A composition (E-4) was obtained in the same manner as in Example 2, except that 500 g of the ethylene resin (E-3) obtained in Production Example 3 and 500 g of polyethylene were used.

[0090] The obtained composition (E-4) was subjected to the same method as in Example 1 to obtain a sliding member.

[0091] The obtained sliding member exhibited a limit PV value of 350 kPa·m / s, a dynamic friction coefficient of 0.16, and a mass loss of 4.4 mg in a reciprocating flat wear test.

[0092] Example 5 250 g of the ethylene resin (H-1) obtained in Production Example 1, polyethylene (manufactured by Tosoh Corporation, (product name) Nipolon Hard 4010 (MFR = 5.4 g / 10 min, density = 964 kg / m 3 ), 750 g of NH4010 (hereinafter sometimes referred to as NH4010) and 750 g of NH4025N were dry-blended in the form of pellets, and then melt-kneaded at 200°C, 50 rpm, and a discharge rate of 1.3 kg / h using a single-screw extruder (manufactured by Toyo Seiki Seisakusho, (product name) Labo Plastomill Single-screw Extruder D2025N) to obtain composition (E-5). The MFR of composition (E-5) was 2.5 g / 10 min.

[0093] The obtained composition (E-5) was subjected to the same method as in Example 1 to obtain a sliding member.

[0094] The obtained sliding member exhibited a limit PV value of 400 kPa·m / s, a dynamic friction coefficient of 0.18, and a mass loss of 7.5 mg in a reciprocating flat wear test.

[0095] [Table 2]

[0096] Comparative Example 1 A composition (E-6) was obtained in the same manner as in Example 2, except that 100 g of Million 030S (trade name, manufactured by Mitsui Chemicals, Inc.) was used instead of the ethylene-based resin (E-2).

[0097] The resulting composition (E-6) was subjected to the same method as in Example 1 to obtain a member.

[0098] The obtained material had a limit PV value of 300 kPa·m / s, a dynamic friction coefficient of 0.22, and a mass loss of 7.0 mg in a reciprocating flat wear test. The limit PV value was low, the material was prone to melting due to friction, and it had poor sliding properties.

[0099] Comparative Example 2 A composition (E-7) was obtained in the same manner as in Example 2, except that 250 g of the ethylene resin (E-1) obtained in Production Example 1 and 750 g of the polyethylene (E-4) obtained in Production Example 4 were used.

[0100] The resulting composition (E-7) was subjected to the same method as in Example 1 to obtain a member.

[0101] The obtained material had a limit PV value of 300 kPa·m / s, a dynamic friction coefficient of 0.25, and a mass loss of 25.0 mg in a reciprocating flat wear test, and was therefore poor in wear resistance and slipperiness.

[0102] Comparative Example 3 An attempt was made to extrude 40 g of ultra-high molecular weight polyethylene (product name GUR4150, manufactured by Celanese Corp.) and 0.08 g of an antioxidant (product name Irganox B225, manufactured by BASF). However, this was difficult, so a part was produced from the powder in the same manner as in Example 1.

[0103] The obtained material had a limit PV value of 250 kPa·m / s, a dynamic friction coefficient of 0.28, and a mass loss of 4.0 mg in a reciprocating flat abrasion test. The limit PV value was low, the material was prone to melting due to friction, and it also had poor slipperiness.

[0104] Comparative Example 4 A commercially available PTFE sheet (purchased from AS ONE Corporation) was adjusted to the dimensions of 30 mm x 30 mm x 3.5 mm and 150 mm x 150 mm x 0.5 mm, and these were used as test samples for the abrasion test and the reciprocating motion planar abrasion test, respectively.

[0105] The evaluation results of the commercially available PTFE sheet are shown in Table 3. It was inferior in abrasion resistance.

[0106] Comparative Example 5 Commercially available POM sheets (manufactured by Mitsubishi Chemical Advanced Materials Co., Ltd.) were cut to sizes of 30 mm x 30 mm x 3.5 mm and 150 mm x 150 mm x 0.5 mm, and used as test samples for the abrasion test and the reciprocating motion planar abrasion test, respectively.

[0107] The evaluation results of the commercially available POM sheet are shown in Table 3. It was inferior in sliding properties and abrasion resistance.

[0108] [Table 3] [Industrial Applicability]

[0109] INDUSTRIAL APPLICABILITY The sliding member of the present invention is excellent in moldability, slidability, wear resistance and good sliding properties, and therefore can be used in a variety of applications, including lining materials, bearing parts for industrial machinery and the like, line parts for the food industry, rotating parts such as gears, medical parts such as artificial joint parts, sheet materials, film materials, rods, pipes and rails, and is expected to improve the productivity and extend the life of the members.

Claims

1. (1) An ethylene-based resin having a melt flow rate (HLMFR) of 0.01 to 100 g / 10 min at a temperature of 190° C. and a load of 21.6 kg in accordance with JIS 6922-2:1997 and a bimodal elution curve measured by gel permeation chromatography; and a melt flow rate (MFR) of 0.01 to 10 g / 10 min at a temperature of 190° C. and a load of 2.16 kg in accordance with JIS 6922-2:1997 and a density of 930 to 980 kg / m as measured according to JIS K6922-1 (1997). ３ A sliding member, characterized in that it is a member made of a polyethylene composition containing a polyethylene represented by the formula:

2. 2. The sliding member according to claim 1, wherein the ethylene-based resin satisfies the following characteristic (2): (2) The elution curve measured by gel permeation chromatography has two peaks, and when the elution curve is expressed as a differential molecular weight distribution (x-axis: Log [M], y-axis: differential distribution value) and the peak is divided into two normal distributions according to the following formula (i), the following (2-1) to (2-3) are satisfied: f(x)=a×(1 / (2π(σ ２ )) （１／２） ) x ２ ) / (2(s ２ ))) formula (i) (Here, a is the peak intensity, σ is the standard deviation, x is the variable, and μ is the average.) (2-1): The weight average molecular weight, calculated as linear polyethylene, based on the peak on the high molecular weight side is 900,000 to 5,000,000, and the molecular weight distribution, expressed as weight average molecular weight / number average molecular weight, is 2.0 to 5.

0. (2-2): The weight average molecular weight, calculated based on the peak on the low molecular weight side, is 50,000 to 500,000, and the molecular weight distribution is 2.0 to 5.0, calculated based on linear polyethylene. (2-3): The weight ratio of the high molecular weight peak to the weight ratio of the low molecular weight peak is greater than 5 / 95 and smaller than 80 / 20.

3. 3. The sliding member according to claim 1, wherein the ethylene resin also satisfies the following characteristic (3): (3) The molecular weight distribution, calculated as standard polyethylene, measured by gel permeation chromatography is 4.0 or more and less than 50.

4. 3. The sliding member according to claim 1, wherein the limit PV value is 350 kPa·m / s or more.

5. 3. The sliding member according to claim 1, wherein the dynamic friction coefficient is less than 0.

20.

6. 3. The sliding member according to claim 1, which is a wear-resistant sliding member having a mass loss of less than 10 mg in a reciprocating flat wear test.

7. 3. The sliding member according to claim 1, wherein the ethylene-based resin is an ethylene homopolymer.

8. 3. The sliding member according to claim 1, which is a sheet-like sliding member.

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