WO2013146825A1

WO2013146825A1 - Ethylene-based polymer for producing abrasion-resistant resin molding, ethylene-based resin composition for producing abrasion-resistant resin molding, abrasion-resistant resin molding, and method for producing same

Info

Publication number: WO2013146825A1
Application number: PCT/JP2013/058873
Authority: WO
Inventors: 丹那　晃央; 清水　史彦; 佐藤　直正; 書佳山田
Original assignee: 日本ポリエチレン株式会社
Priority date: 2012-03-26
Filing date: 2013-03-26
Publication date: 2013-10-03
Also published as: JP2013227539A

Abstract

An ethylene-based polymer for producing an abrasion-resistant resin molding, the polymer satisfying (1) to (5). (1) Is either an ethylene homopolymer or a copolymer of ethylene and a C_3-20 α-olefin. (2) Is polymerized using a single-site catalyst. (3) Has a weight-average molecular weight Mw that is 300,000 to less than 1,000,000. (4) Has a melting point Tm 130°C to less than 135°C. (5) Has a sand/rubber wheel abrasion test performance of 0.035-0.24 cm³ as measured for a sample fabricated from the ethylene-based polymer.

Description

Ethylene polymer for production of wear-resistant resin molded body, ethylene-based resin composition for production of wear-resistant resin molded body, wear-resistant resin molded body and method for producing the same

The present invention relates to an ethylene-based polymer for producing a wear-resistant resin molded product and an abrasion-resistant product capable of producing a wear-resistant resin molded product having a sand / rubber wheel wear performance of 0.035 cm ³ or more and 0.24 cm ³ or less. The present invention relates to an ethylene-based resin composition for producing an adhesive resin molded article, an abrasion-resistant resin molded article obtained by molding the composition, and a method for producing the same.

Ultra high molecular weight polyethylene is a polyethylene resin having a very high molecular weight with a viscosity average molecular weight exceeding 1 million. Ultra high molecular weight polyethylene is known as a resin having excellent wear resistance and a low friction coefficient, and is used in industrial fields where high wear resistance is required by utilizing this property (for example, non-patented). Reference 1).
The high wear resistance of ultra high molecular weight polyethylene has been attributed to its very high molecular weight.
On the other hand, ultra-high molecular weight polyethylene has a very high molecular weight, so even when heated above the melting point of polyethylene, the melt viscosity is very high and the relaxation time is extremely long, so the time scale of molding conditions used industrially Is known not to melt and flow. For example, the melt viscosity of ultra high molecular weight polyethylene is higher than 10 ⁶ Pa · sec at 180 ° C. For this reason, even if it is more than the melting | fusing point, ultra high molecular weight polyethylene shows the behavior like a rubber-like solid instead of the melted liquid (for example, patent document 1). Therefore, ultra high molecular weight polyethylene has a problem that it is extremely difficult to mold using a melt processing method widely used for molding ordinary polyethylene, for example, injection molding, extrusion molding, blow molding and the like.

Therefore, conventionally, in the molding of ultra-high molecular weight polyethylene, a molding method different from the melt processing method, for example, ram extrusion, compression molding, sintering, machining, skiving, high hydrostatic pressure processing, Complex molding methods such as a solution method and a gel method are used. However, these molding methods are much less productive than the melt processing methods described above. For this reason, this improvement in productivity has been a major issue in the industrial practical application of ultrahigh molecular weight polyethylene.

In addition, it has been reported that grain boundaries (melting defects) of raw material powder are observed even after molding in a molded body of ultra-high molecular weight polyethylene obtained by a molding method different from the melt processing method (Patent Document 2). Non-Patent Document 1). Such grain boundaries are thought to be generated because ultra high molecular weight polyethylene does not melt and flow during molding, and the grain boundaries that are generated adversely affect the mechanical properties of the molded product, in particular the fracture characteristics. It was.

Under such circumstances, attempts have been made to improve the moldability of ultra-high molecular weight polyethylene. Specifically, a technique for improving the moldability of ultrahigh molecular weight polyethylene by adding a solvent, a plasticizer, a processing aid, low molecular weight polyethylene or the like to ultrahigh molecular weight polyethylene has been proposed. However, these methods have problems in that the moldability is not sufficiently improved, and when these methods are used, the wear resistance of the finally obtained molded body is greatly impaired.

For this reason, ultra high molecular weight polyethylene has not yet been widely applied to general uses requiring wear resistance, despite having excellent wear resistance. It is.

In contrast, wear-resistant polyethylene that can be melt-molded has been proposed. In Patent Document 2, the weight average molecular weight Mw is in the range of 150,000 to 1,000,000, the number average molecular weight Mn is at least 25000, Mw / Mn is in the range of 1.3 to 10, and the wear coefficient is 3 Polyethylene has been proposed that satisfies the requirement of less than 2 × 10 ⁻⁴ mm ³ / mN.
Patent Document 3 proposes an ethylene polymer having excellent wear characteristics and a composition thereof. Here, polyethylene having a viscosity average molecular weight Mv of 100,000 or more and a melting point peak of 135 ° C. or more is proposed.
In Patent Document 2, a special evaluation method proposed by Hutchings et al. (Hereinafter referred to as “Hutchings method”, specifically, see Non-Patent Document 2) is used as a method for evaluating wear resistance of a molded body. In Patent Document 3, a sand slurry wear test is used as a method for evaluating wear resistance.

There are various methods for evaluating the wear resistance of a material depending on the material to be evaluated. In general, the results of wear tests, which are the criteria for determining wear resistance of materials, are highly dependent on the test method, and in evaluating the wear resistance of materials from a practical point of view, It is necessary to select an optimum wear test method in consideration of the type of wear that is used.
That is, if an inappropriate test method is used for a certain material, the wear resistance of the material may not be accurately evaluated.

Typical test methods used to evaluate the wear resistance of ultra-high molecular weight polyethylene molded products include “sand slurry wear test (American Testing Materials Association Standard ASTM D4020)” and “sand / rubber wheel wear test (US Test Material Association Standard ASTM G65) ”.
Any of these test methods or the evaluation method employed in Patent Document 2 is a method for measuring the amount of resin lost due to wear due to contact with sand or inorganic particles. The wear resistance will be evaluated as high.

U.S. Pat. No. 4,281,070 Japanese National Table 2004-515591 Japanese Unexamined Patent Publication No. 11-106417

However, these wear test methods have been developed for the purpose of evaluating the wear resistance of ultra-high molecular weight polyethylene moldings. When applying these test methods to molded products of non-ultra high molecular weight polyethylene, that is, relatively low molecular weight polyethylene, it is confirmed that the test method is an appropriate evaluation method for molded products of low molecular weight polyethylene. It is necessary to.

However, in the prior art, the test method developed for the ultra-high molecular weight polyethylene molded body was applied to the molded body of low molecular weight polyethylene as it was without sufficiently confirming this.
As a result, when evaluating a polyethylene molded article having a molecular weight lower than that of ultra-high molecular weight polyethylene using a test method for ultra-high molecular weight polyethylene, the evaluation result is that it has wear resistance comparable to that of ultra-high molecular weight polyethylene. Although it may be obtained, there is a problem in that it does not actually have wear resistance that can withstand practical use and may not be used in applications that require wear resistance. In particular, among the test methods for ultra-high molecular weight polyethylene, the test method described in Patent Document 2 and the sand slurry wear test are resins that are insufficiently suitable for applications that actually require wear resistance. In spite of the fact, there was an excessive evaluation result.

Specifically, Patent Document 2 discloses a copolymer of ethylene and 1-hexene as a preferable resin having abrasion resistance. However, this copolymer has not actually been used in a field where high wear resistance is required, and it can be considered that the copolymer actually lacks wear resistance. Patent Document 3 describes a low molecular weight resin having a viscosity average molecular weight Mv of 100,000 or more. However, in fact, this polymer has not been used in a field where high wear resistance is required, and it may be considered that the wear resistance is actually insufficient.

The reason why the resin moldings described in Patent Documents 2 and 3 cannot withstand practical use is considered to be due to the heat resistance of the resin. That is, in an environment where the wear-resistant resin molded body is actually used, the temperature of the material rises due to collision and friction of sand, gravel, various particles, various objects, and the like. In particular, when sand or the like collides with the molded body, the temperature may locally rise to the vicinity of the melting point of polyethylene. Moreover, it is often used not only in collision and friction but also in an environment that comes into contact with a high-temperature fluid such as high-temperature waste water or exhaust gas. Therefore, in the development of a wear-resistant resin molded product suitable for actual use, it is considered that the property required for the material must have heat resistance in addition to wear resistance.

Examining the heat resistance, the resin described as having the abrasion resistance described in Patent Document 2 has a melting point (the peak temperature of the endothermic peak of the differential scanning calorimeter DSC) of about 127 ° C. from its physical property values. This is considered to be inferior in heat resistance, so that it cannot be applied to actual wear resistance.
In addition, since the resin described in Patent Document 3 that has abrasion resistance has a low viscosity average molecular weight, it contains a relatively large amount of a lower molecular weight wax-like component, and this acts as a plasticizer. It is thought that heat resistance is impaired, and it cannot be applied to actual wear-resistant applications.

Thus, conventionally, when designing a relatively low molecular weight polyethylene having wear resistance comparable to that of ultra-high molecular weight polyethylene, it is appropriate to determine what test method should be used to evaluate the wear resistance of the material. The wear test method was not clarified.
And, as described above, the reason why the resin described in Patent Documents 2 and 3 cannot be applied to applications that actually require wear resistance is that of polyethylene having a relatively low molecular weight as described above. Since the wear test method for evaluating the property is not appropriate, it is suggested that the wear resistance of the appropriate resin has not been evaluated. In other words, it cannot be said that a test method for evaluating wear resistance is appropriate, and that no consideration has been given to materials and molded bodies that have heat resistance in addition to melt moldability and wear resistance. It is done.

For this reason, in the past, despite the need to provide polyethylene that can be melt-molded while having wear resistance that can withstand practical use comparable to ultra-high molecular weight polyethylene, Nothing that fully satisfies this requirement has been realized.

It should be noted that the investigation by the present inventors confirmed that the sand / rubber wheel wear test is a test method that can appropriately evaluate the wear resistance performance of a material regardless of the molecular weight range. In other words, the sand / rubber wheel abrasion test is an evaluation method that appropriately shows the wear resistance performance of materials in both the molecular weight region used for ultra-high molecular weight polyethylene and lower molecular weight polyethylene. It was confirmed that the evaluation method was consistent with the correlation with wear. This is presumed to be because the sand / rubber wheel abrasion test also takes heat to some extent on the resin to be evaluated, and therefore the evaluation also incorporates heat resistance.

In such a situation, the problem to be solved by the present invention is to produce a wear-resistant resin molded article having excellent wear resistance as measured by a sand / rubber wheel wear test and having a good balance between moldability and heat resistance. An object of the present invention is to provide an ethylene polymer, an ethylene resin composition for producing an abrasion-resistant resin molded article, an abrasion-resistant resin molded article, and a method for producing the same.

As a result of diligent studies to solve the above problems, the inventors of the present invention manufactured an ethylene polymer using a single site catalyst, and controlled the molecular weight and melting point of the ethylene polymer to a specific range. As a result, the present inventors have found that the above problems can be solved, and have reached the present invention.

That is, the gist of the present invention is as follows.

[1] An ethylene-based polymer for producing an abrasion-resistant resin molded article that satisfies the following (1) to (5)
(1) An ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms (2) Polymerized using a single site catalyst (3) Weight average molecular weight Mw (4) Melting point Tm is 130 ° C. or higher and lower than 135 ° C. (5) Sand / rubber wheel produced from a press piece obtained by press molding the ethylene-based polymer The sand / rubber wheel wear performance measured for the test specimen for wear test is 0.035 cm ³ or more and 0.24 cm ³ or less.

[2] An ethylene resin composition for producing an abrasion-resistant resin molded article, which contains an ethylene polymer satisfying the following (1) to (4) and satisfies the following (6).
(1) An ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms (2) Polymerized using a single site catalyst (3) Weight average molecular weight Mw (4) Melting point Tm is 130 ° C. or higher and lower than 135 ° C. (6) Sand / rubber made from a press piece obtained by press-molding the ethylene-based resin composition Sand / rubber wheel wear performance measured on a test piece for wheel wear test is 0.035 cm ³ or more and 0.24 cm ³ or less.

[3] A method for producing a wear-resistant resin molded product having a sand / rubber wheel wear performance of 0.035 cm ³ or more and 0.24 cm ³ or less, wherein the wear-resistant resin molded product according to [1] is produced. A method for producing an abrasion-resistant resin molded article, wherein the ethylene-based polymer or the ethylene-based resin composition for producing an abrasion-resistant resin molded article according to [2] is molded in a melt-flowable state.

[4] A wear-resistant resin molded product obtained by the method for producing a wear-resistant resin molded product according to [3].
[5] A wear-resistant resin member comprising the wear-resistant resin molded article according to [4].
[6] The wear-resistant resin member is a gear, cam, slider, lever, arm, clutch, pulley, roller, roller, key stem, key top, shutter, reel, washer, piston, cylinder, guide rail, ball bearing, The wear-resistant resin member according to [5], which is a mechanical component represented by a nut, a bolt, a screw, a shaft, a bearing, and the like.
[7] The wear-resistant resin member according to [5], wherein the wear-resistant resin member is a coating material represented by a lining material, a steel pipe coating material, a coating material, a ski sole, a snowboard sole, and the like. .
[8] The wear-resistant resin member is a member for an artificial graft tissue represented by an artificial hip joint, an artificial shoulder joint, an artificial spine, an artificial knee joint, an artificial elbow joint, an artificial ankle joint, an artificial finger joint, and the like. The wear-resistant resin member according to [5].
[9] The wear-resistant resin member is a liquid or gas continuity represented by tubes, hoses, pipes, valves, joints, seals, gaskets, O-rings, columns, tanks, containers, bags, bottles, etc. The wear-resistant resin member according to [5], which is a route member.
[10] The wear-resistant resin member according to [5], wherein the wear-resistant resin member is an intermediate processed product for a wear-resistant resin member represented by a sheet, a plate, a rod, a block, a round bar, and the like. .

By using at least one of the ethylene-based polymer for producing an abrasion-resistant resin molded body of the present invention and the ethylene-based resin composition for producing an abrasion-resistant resin molded body, an ethylene-based resin molded body having excellent abrasion resistance. Can be obtained by a general resin molding method such as a melt molding method.
The wear-resistant resin molded article provided by the present invention can be applied to an application field in which ultrahigh molecular weight polyethylene has been used, and this wear-resistant resin molded article is highly productive by a melt molding method. Therefore, it is extremely useful industrially.
Further, the wear-resistant resin molded article of the present invention has relatively high crystallinity and can be used in fields or environments where heat resistance is required. From this viewpoint, it is extremely useful industrially.

DESCRIPTION OF EMBODIMENTS Embodiments of the present invention will be described in detail below. However, the description of constituent elements described below is an example (representative example) of embodiments of the present invention, and the present invention is specified by these contents. It is not a thing.

In the following description, the term “polymerization” is a collective term for homopolymerization by one type of monomer and copolymerization by a plurality of types of monomers, and it is not particularly necessary to distinguish between the two. Collectively, it is simply described as “polymerization”.

[Abrasion resistance evaluation]
There are several methods for evaluating the wear resistance of a molded product obtained by molding a polymer. As in the present invention, in the field where high wear resistance is required such that ultra high molecular weight polyethylene is used, the following sand / rubber wheel abrasion test (Sand Wheel Absorption Test) and sand slurry abrasion test (Sand) Two of the Slurry Abrasion Tests are widely used.
In addition, Hutchings et al. Evaluate the wear resistance of a material by the following method (see Non-Patent Document 2).

However, the results of the wear test are highly dependent on the test method, and when evaluating the wear resistance of a material from a practical point of view, the material is actually used in any environment and exposed to any wear. Therefore, it is necessary to select an optimal wear test method.
As will be clarified in the section of Examples below, the present inventors have examined each wear test, and as a result, the sand slurry wear test cannot be used in a field that actually requires wear resistance. In order to lead to almost the same evaluation results for polyethylene having a relatively low molecular weight, specifically, a molecular weight of less than 1 million, particularly 300,000 or less, and ultra-high molecular weight polyethylene, the low molecular weight polyethylene tends to be overestimated. I found it. That is, it was found that the sand / slurry wear test is not suitable as a method for evaluating wear resistance.
On the other hand, the sand / rubber wheel abrasion test can clearly distinguish between the abrasion resistance of the relatively low molecular weight polyethylene and the abrasion resistance of the ultra high molecular weight polyethylene as described above. It was judged that it was suitable for evaluation of a molded article having properties.

<Sand / rubber wheel wear test>
The sand / rubber wheel abrasion test is a test method defined by ASTM G65, and a sand / rubber wheel abrasion tester that satisfies the standard is used.
Specifically, a test piece of 0.25 inch × 1.00 inch × 3.00 inch is prepared using a band saw, and the mass (g) of the test piece is measured. The test sand (22.7 kg) is then placed in the hopper of a sand / rubber foil wear tester. The test piece is fixed to a fixing jig of a sand / rubber wheel abrasion tester, and the rubber wheel is rotated at 200 rpm while flowing the test sand at 300 g / min. At room temperature, the test piece is applied to the rubber wheel at a load of 30 pounds. Press. The test is terminated when the rubber wheel rotates 3200 times. Remove the specimen from the fixture and wipe off the sand adhering to the specimen surface. Next, the mass (g) of the test piece is measured. The mass reduction amount (g) of the test piece due to wear is calculated, and the loss volume (cm ³ ) due to wear is determined by dividing the mass reduction amount (g) by the density (g / cm ³ ) of the test piece. In this specification, the loss volume (cm ³ ) obtained by this method is referred to as sand / rubber wheel wear performance (SWA, Sand Wheel Ablation).

As the sand used in the test, 50-70 test sand manufactured by American Foundry Sand is used. This sand is prepared by a sieve so that the particle size is approximately in the range of 50 mesh (300 μm) to 70 mesh (212 μm). More precisely, the particle size distribution satisfies the following specifications.
Specifications: 95% by weight or more of sand having a particle size of 212 μm or more and less than 300 μm, and 5% by weight or less of sand having a particle size of 300 μm or more and less than 425 μm

<Sand slurry wear test>
The sand slurry test is performed as follows based on ASTM D4020.
Specifically, a test piece of 0.250 inch × 1.000 inch × 2.750 inch is prepared by cutting from a pressed piece of material used for the test. A 11/32 inch hole is drilled in the center of the resulting specimen, and another 9/64 inch hole is drilled about 1/8 inch away from the hole.
The weight (g) of the test piece is measured, and the test piece is fixed to the apparatus with a bolt through a 11/32 inch hole drilled in the center with the cut surface of the test piece facing up. Next, the pin protruding from the shaft is passed through a 9/64 inch hole to determine the mounting angle of the test piece.
Weigh 50-70 test alumina (450 g) from American Foundry Sand and pour into a cup. The particle size distribution of the alumina is prepared in the same manner as the 50-70 test sand made by American Foundry Sand. Then 300 g of water is weighed and added to the cup. The cup containing the water / alumina slurry is fixed to the apparatus, and the specimen is completely immersed in the slurry.
The shaft and the test piece are rotated at 1750 rpm for 120 minutes while the chiller unit is operated and the temperature is maintained at 23 ° C. ± 2 ° C. After completion, the test piece is removed from the apparatus, and water and alumina remaining on the surface of the test piece are wiped off and dried. After confirming that the water has completely dried, the mass (g) of the test piece is measured, and the mass reduction amount (g) of the test piece due to wear is calculated. Finally, the mass loss (g) is divided by the density (g / cm ³ ) of the test piece to determine the loss volume (cm ³ ) due to wear. In the present specification, the loss volume (cm ³ ) obtained by this method is referred to as sand slurry abrasion performance (Sand Slurry Ablation).

<Method of Hutchings>
A 1-inch tungsten carbide sphere (made by Atlas Ball & Bearing Co. Ltd., surface roughness: 400 nm) clamped between two coaxial drive shafts was rotated at a constant speed of 150 rpm, and the test piece was adjusted to a diameter of 0. Pressing with a normal force F of 27 N, an aqueous slurry of silicon carbide (average particle size: 4 to 5 μm, concentration: 0.75 g / cm ³ ) is dropped onto the sphere at a supply rate of 5 cm ³ / min. From the start to the end of the test, the rotation speed of the sphere is 9000 rotations. This corresponds to 718 m as the sliding distance S over which the sphere slipped on the test piece. After the test, the wear crater generated by polishing the test piece is measured using an optical microscope, and the wear volume V (mm ³ ) is measured. The wear resistance performance of the material is evaluated by a wear coefficient k (mm ³ / Nm) defined by V = kSF, and the smaller k is, the better the wear resistance of the material is.

[Ethylene polymer for production of wear-resistant resin moldings]
The ethylene-based polymer for producing an abrasion-resistant resin molded body of the present invention (hereinafter sometimes referred to as “the ethylene-based polymer of the present invention”) satisfies the following (1) to (5): To do.
(1) An ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms.
(2) Polymerized using a single site catalyst.
(3) The weight average molecular weight Mw is 300,000 or more and less than 1 million.
(4) Melting | fusing point Tm is 130 degreeC or more and less than 135 degreeC.
(5) Sand / rubber wheel wear performance measured on a test piece for sand / rubber wheel wear test prepared from a press piece obtained by press-molding the ethylene-based polymer is 0.035 cm ³ or more and 0.24 cm. ³ or less.

1. Ethylene polymer The ethylene polymer in the present invention is a homopolymer of ethylene or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms.

1.1 Monomer 1.1.1 Ethylene Ethylene, which is a raw material monomer of the ethylene polymer of the present invention, is represented by the formula CH ₂ = CH ₂ and is the main raw material monomer in the ethylene polymer of the present invention.

1.1.2 α-Olefin An α-olefin that can be used as a copolymerization component with ethylene in the ethylene polymer of the present invention is specifically represented by the general formula CH ₂ ═CH—R. Monomer. Here, R is a hydrocarbon group having 1 to 18 carbon atoms, and may have at least one of a branch, a ring, and an unsaturated bond.
If the carbon number of R is greater than 18, sufficient polymerization activity may not be exhibited. Preferred α-olefins are α-olefins in which R has 10 or less carbon atoms, that is, α-olefins having 3 to 12 carbon atoms.

Specific preferred α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 3-methyl-1-butene, 4-methyl-1-pentene, vinylcyclohexene. And styrene. One kind of these α-olefins may be used, or two or more kinds of α-olefins may be used in combination.

1.2 Composition The ethylene polymer of the present invention is an ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms. That is, the ethylene polymer of the present invention may be either a homopolymer or a copolymer as long as the characteristics of the present invention are satisfied, and is not particularly limited. The ethylene homopolymer here refers to a polymer obtained by polymerizing only ethylene as a raw material monomer.
When the ethylene-based polymer of the present invention is a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, the content of the α-olefin as a copolymerization component is not particularly limited, but a smaller one is preferable. .

Specifically, the amount of the copolymer component contained in the ethylene polymer is not particularly limited, but is usually 5% by weight or less, preferably 2% by weight or less, based on the total weight of the ethylene polymer. More preferably, it is 1% by weight or less, particularly preferably 0.5% by weight or less.
If the content of the copolymer component in the ethylene polymer exceeds the above upper limit, the crystallinity of the ethylene polymer is lowered, the wear resistance is lowered, or practical physical properties such as rigidity and heat resistance are impaired. There is a case. The lower limit of the content of the copolymer component is not particularly limited, and is preferably as small as possible, and more preferably contains a trace amount that does not deteriorate the practical physical properties of the present invention.
The ethylene polymer is most preferably an ethylene homopolymer because of its high crystallinity, easy physical property adjustment, and high productivity.

The ethylene polymer of the present invention may be a single ethylene polymer or a mixture of two or more ethylene polymers. When two or more types of ethylene polymers are used, two or more types of ethylene polymers polymerized by changing the monomer and polymerization conditions using the same catalyst may be used, or polymerization is performed using different catalysts. Two or more types of ethylene polymers may be used. In addition, a different catalyst means here that the kind and ratio of arbitrary components, such as a polymerization active seed | species in a below-mentioned single site catalyst, a support | carrier, a cocatalyst, and a promoter, differ. In addition, the two or more types of ethylene-based polymers may have different types and contents of copolymerization components, and may have different molecular weights and melting points.

1.3 Molecular Weight The weight average molecular weight Mw of the ethylene polymer of the present invention is 300,000 or more and less than 1 million. When the weight average molecular weight Mw of the ethylene polymer exceeds the above upper limit, the melt viscosity becomes high, and even when heated to the melting point or higher, it behaves like a rubber-like solid and fluidity at the time of melting cannot be obtained. On the other hand, when the weight average molecular weight Mw is less than the above lower limit, the sand / rubber wheel wear performance of the obtained molded article is deteriorated and the wear resistance is lowered.
As long as the weight average molecular weight Mw of the ethylene polymer satisfies the object of the present invention, the lower one is preferable in terms of improving the fluidity at the time of melting. It is. Moreover, the higher lower limit of the weight average molecular weight Mw is preferable from the viewpoint of improving the wear resistance, specifically preferably 350,000 or more, more preferably 400,000 or more.

Further, the molecular weight distribution (Mw / Mn) of the ethylene-based polymer of the present invention is not particularly limited, but is preferably smaller, specifically 5.0 or less, particularly 4.5 or less. preferable.

The number average molecular weight Mn of the ethylene polymer of the present invention is not particularly limited, but is usually 80,000 or more, preferably 100,000 or more, more preferably 150,000 or more, and usually 500,000 or less, preferably It is 400,000 or less, more preferably 350,000 or less.
If the number average molecular weight Mn of the ethylene-based polymer is less than the lower limit, the molecular weight distribution (Mw / Mn) increases, the number of structural defects tends to increase, and the wear resistance tends to decrease. In general, the higher the number average molecular weight Mn, the less carbon-carbon bonds in the polyethylene chain, and the fewer structural defects based on it, so the higher the number average molecular weight, the better the wear resistance. I think that.

The weight average molecular weight Mw and the number average molecular weight Mn of the ethylene polymer are measured by the methods described in the Examples section below.
When the ethylene polymer of the present invention is composed of two or more ethylene polymers, the weight average molecular weight Mw and number average molecular weight Mn of the ethylene polymer are relative to the mixture of these two or more ethylene polymers. Measured. Therefore, the weight average molecular weight Mw and the number average molecular weight Mn of the mixture of the ethylene polymers may be in the above ranges, and the weight average molecular weight Mw and the number average molecular weight Mn of each ethylene polymer are not necessarily in the above ranges. May be.

1.4 Melting | fusing point Melting | fusing point Tm of the ethylene-type polymer of this invention is 130 degreeC or more and less than 135 degreeC. When the melting point Tm of the ethylene polymer is less than the above lower limit, the sand / rubber wheel wear performance intended in the present invention cannot be obtained. When the melting point Tm exceeds the above upper limit, there may be a problem that the plasticization rate decreases, the productivity decreases, and the impact resistance deteriorates.
For the reasons described above, the ethylene polymer of the present invention preferably has higher heat resistance. That is, as a physical property, a higher melting point is preferable. And since the melting point of polyolefin generally represents the crystallinity of the polyolefin, the higher the crystallinity is preferable.

The melting point Tm of the ethylene polymer is measured by the method described in the Examples section below.
When the ethylene polymer of the present invention comprises two or more ethylene polymers, the melting point Tm of the ethylene polymer is measured with respect to a mixture of these two or more ethylene polymers. Therefore, the melting point Tm of the mixture of ethylene polymers only needs to be in the above range, and the melting point Tm of each ethylene polymer does not necessarily have to be in the above range.

1.5 Other Structural Features The ethylene polymer of the present invention is not particularly limited with respect to branching in the structure, but it is preferable that the number of short chain branches is small. This is because the smaller the number of short chain branches, the lowering of the melting point Tm can be suppressed, and the wear resistance can be improved.
The method for controlling the number of short chain branches is not particularly limited,
(1) A method of controlling the number of short-chain branches by controlling the amount of α-olefin used as a copolymerization component,
(2) A method of controlling short chain branching by selecting a catalyst used for polymerization,
(3) A method of controlling the number of short chain branches by controlling the polymerization temperature and the polymerization pressure can be mentioned.

The ethylene polymer of the present invention may have a carbon-carbon unsaturated bond in the main chain of the polymer. Specific examples of the carbon-carbon unsaturated bond include a vinylene group, a vinylidene group, a vinyl group, and the like, and a vinylene group is preferable. Due to the presence of such a carbon-carbon unsaturated bond, the crosslinking proceeds efficiently when the ethylene polymer is crosslinked using an organic peroxide or radiation.
In order to introduce such a carbon-carbon unsaturated bond into the main chain of the ethylene-based polymer, a catalyst that releases hydrogen molecules from the growth terminal during the polymerization reaction may be used. If it is a single site catalyst, as an example, Organometallics 1999, 18, 3781. There are some examples.

1.6 Physical Properties Of the mechanical strength of the ethylene polymer of the present invention, higher impact resistance is preferred. This is particularly important for resisting wear that is subject to strong external forces in a short time. Although there are a plurality of methods for evaluating impact resistance, in the Izod impact test (JIS K7110) which is the most representative measurement method, although not particularly limited, it is usually preferably 60 kJ / m ² or more. In particular, it is preferably 80 kJ / m ² . In addition, the test piece of this Izod impact test was produced by compression molding.
When the ethylene polymer of the present invention comprises two or more ethylene polymers, the Izod impact test of the ethylene polymer is measured on a mixture of these two or more ethylene polymers. . Accordingly, the Izod impact test of the ethylene polymer mixture may be within the above range, and the Izod impact test of each ethylene polymer may not necessarily be within the above range.
The ethylene polymer of the present invention usually has melt fluidity. Having melt fluidity means having fluidity to the extent that it can be applied to normal resin melt processing, etc. by heating, specifically, among the evaluation conditions for resin fluidity described below, A state in which at least one of a melt flow rate (MFR) and a flow ratio melt flow rate (HLMFR) can be measured.

The ethylene-based polymer of the present invention exhibits a wear resistance of 0.035 cm ³ or more and 0.24 cm ³ or less in a sand / rubber hole wear test (ASTM G65). The lower limit of the sand / rubber wheel wear performance is preferably 0.04 cm ³ and the upper limit is preferably 0.20 cm ³ . If the sand / rubber wheel wear performance exceeds the above upper limit, it does not have sufficient wear resistance for practical use in an application field where ultra-high molecular weight polyethylene is actually used. May be difficult to manufacture.
In addition, the sand / rubber wheel wear performance of the ethylene-based polymer is specifically measured by the method described in the Examples section below.
When the ethylene polymer of the present invention is composed of two or more ethylene polymers, the sand / rubber wheel wear performance of the ethylene polymer is also a value measured for the mixture of ethylene polymers. It is only necessary that the mixture of the base polymer satisfies the above sand / rubber wheel wear performance range.

2. Production Method of Ethylene Polymer In the production of the ethylene polymer of the present invention, various known polymerization reactions and production methods can be used without departing from the object of the present invention.

2.1 Raw Material, etc. In the production of the ethylene polymer of the present invention, ethylene and, if necessary, an α-olefin having 3 to 20 carbon atoms are used as a raw material monomer. The composition ratio, purity, and the like of each raw material are not particularly limited as long as the performance of the obtained polyethylene polymer satisfies the object of the present invention, and is appropriately selected for producing a desired ethylene polymer. Can be adjusted.
Moreover, about the reaction agents, such as a solvent, or polymerization reaction conditions, the desired polyethylene-type polymer can be manufactured combining suitably the conditions mentioned later.

2.2 Single-site catalyst A single-site catalyst is used in the production of the ethylene-based polymer of the present invention. Here, the single site catalyst means a catalyst having a transition metal complex as a polymerization active species. The single-site catalyst is a transition metal complex as the polymerization active species, so the active site is highly uniform, and the polymer (polymer) obtained by polymerization using the single-site catalyst is, for example, a Ziegler-Natta catalyst. Compared with a polymer obtained by polymerization, the molecular weight distribution and composition distribution of the polymer described above are narrow, and in particular, there is an advantage that the amount of low molecular weight components produced is small. When the amount of low molecular weight components in the polymer increases, sand / rubber wheel wear performance deteriorates and mechanical properties such as impact resistance deteriorate, which is not preferable.

Since the ethylene-based polymer of the present invention is produced by polymerization using a single site catalyst, the amount of low molecular weight components that cause such adverse effects is small, and the sand / rubber wheel wear performance and mechanical properties are improved. Is advantageous.

As the single site catalyst used for the production of the ethylene polymer of the present invention, any one can be used without departing from the object of the present invention. Typical examples include metallocene catalysts and nonmetallocene catalysts.

The metallocene catalyst means an olefin polymerization catalyst using as a catalyst component a complex in which one or more optionally substituted cyclopentadienyl groups are coordinated to a metal ion. In contrast, non-metallocene single-site catalysts, also called post-metallocene catalysts, generally do not have a cyclopentadienyl group and are coordinated to metal ions by heteroatoms such as nitrogen, oxygen, and phosphorus. It means a catalyst for olefin polymerization using a complex having a child as a catalyst component.

Hereinafter, in the present specification, Cp, Ind, Azu, BenzInd, H4Ind, H4Azu, Flu, and H8Flu are respectively cyclopentadienyl group, indenyl group, azulenyl group, benzoindenyl group, 4, 5, 6, 7 -Represents a tetrahydroindenyl group, a 5,6,7,8-tetrahydroazurenyl group, a fluorenyl group, a 1,2,3,4,5,6,7,8-octahydrofluorenyl group. In addition, Me, Et, nPr, iPr, nBu, iBu, tBu, Ph, and Cy are methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, respectively. Represents a phenyl group and a cyclohexyl group. Si, Ge, C, O, N, P, Ti, Zr, Hf, and Al are silicon atom, germanium atom, carbon atom, oxygen atom, nitrogen atom, phosphorus atom, titanium atom, zirconium atom, and hafnium atom, respectively. Represents an aluminum atom.

2.2.1 Metallocene Catalyst The metallocene catalyst used in the present invention includes a metallocene complex represented by any one of the following general formulas (1) to (3) and a cocatalyst (also referred to as an activator described later). And a catalyst comprising a combination thereof.

(Y) _m ((R ¹ ) _n Cp) ₂ MX ₂ (1)
Y ((R ¹ ) _n Cp) (Z) MX ₂ (2)
((R ¹ ) _n Cp) ₃ MX (3)

In the general formulas (1) to (3), M represents a metal ion belonging to Group 4 of the periodic table, preferably a metal ion selected from titanium, zirconium and hafnium, more preferably a zirconium ion or a hafnium ion. .
In the production of the ethylene polymer of the present invention, it is necessary to control the weight average molecular weight Mw to a relatively high value of 300,000 or more. The metal is preferable for controlling to a high molecular weight. The valence of the metal is not particularly limited and is usually tetravalent, but rarely trivalent, and rarely divalent.

X represents a ligand coordinated to the metal ion M. Specifically, a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, an alkoxy group having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms, 1 to 20 carbon atoms, preferably An alkylamide group having 1 to 10 carbon atoms, a phosphorus atom-containing hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, or a silicon atom-containing hydrocarbon group having 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms. . When a plurality of Xs are included, the plurality of Xs may be the same as or different from each other. Of the X, a halogen atom, a hydrocarbon group and an alkylamide group are preferably used.

Y represents a bridging group in the metallocene complex. In the metallocene complex of the general formula (1), it represents a crosslinking group that bridges two (R ¹ ) _n Cp. In the metallocene complex of the general formula (2), it is a bridging group that crosslinks (R ¹ ) _n Cp and Z. m represents an integer of 0-2.

Preferred bridging groups Y include (R ² ) ₂ Si, (R ² ) ₂ Ge, and (R ² ) ₂ C. Here, R ² is a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms which may contain a silicon atom or a germanium atom, and adjacent R ² may form a ring with each other. Two R ² may be the same or different from each other.

Specific examples of the bridging group Y include the following. That is, an alkylene group such as a methylene group, an ethylene group, an ethylidene group, a propylidene group, an isopropylidene group, a phenylmethylidene group, an alkylidene group such as a diphenylmethylidene group, a dimethylsilylene group, a diethylsilylene group, a dipropylsilylene group A silicon atom-containing cross-linking group such as a diphenylsilylene group, a methylethylsilylene group, a methylphenylsilylene group, a methyl-t-butylsilylene group, a disilylene group or a tetramethyldisylylene group, a dimethylgermylene group, a diethylgermylene group, Examples thereof include a germanium atom-containing crosslinking group such as a diphenylgermylene group and a methylphenylgermylene group, an alkylphosphine, and an amine group. Among these, an alkylene group, an alkylidene group, a silicon atom-containing crosslinking group, and a germanium atom-containing crosslinking group are particularly preferably used.

Z is a group that binds to Y and can coordinate to the metal ion M. In general, Z is a heteroatom selected from an oxygen atom, a nitrogen atom, and a phosphorus atom, or a group containing these heteroatoms. Specifically, Z is O, R′N, R′P (the meaning of R ′ is the same as R ¹ described later).

((R ¹ ) _n Cp) represents a substituted or unsubstituted cyclopentadienyl group. R ¹ is a hydrogen atom or a hydrocarbon group, and the hydrocarbon group may be substituted with an oxygen atom, a nitrogen atom, a phosphorus atom, a silicon atom, or a germanium atom, and adjacent R ¹ forms a ring with each other May be. When R ¹ is a hydrocarbon group, R ¹ preferably has 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, and most preferably 1 to 15 carbon atoms. Specifically, R ¹ is preferably a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, phenyl group, cyclohexyl group or the like. The n R ^{1 s} may be the same as or different from each other.
n represents an integer of 0 to 4, preferably 0 or 1.

Specific examples of (R ¹ ) _n Cp include the following (i) to (iv).
(I) having one ^{R 1} ^(R 1) Cp
(Ii) having two ^{R ₁ ^(R 1)} 2 Cp
And (iii) a two adjacent having ^{R 1} ^(R ₁₎ 2 Cp, two ^{R 1} has those that form a ring (iv) 4 pieces of ^{R 1} ^(R _{1) 4} Cp, in which two R ^1's are adjacent to form a ring, and the remaining two R ^1's are adjacent to form a ring

Specific examples of (i) include MeCp, EtCp, nPrCp, iPrCp, nBuCp, iBuCp, tBuCp, PhCp, CyCp and the like.

Specific examples of (ii), if the 1-position and 2-position of the cyclopentadienyl group to have been substituents substituted with a substituent ^{R 1,} expressed and 1,2- ^(R ₁₎ 2 Cp, 1,2- (R ¹ ) ₂ Cp and 1,3- (R ¹ ) ₂ Cp are preferable, and R ¹ is more preferably a methyl group, an ethyl group, an n-propyl group, an i-propyl group, or n-butyl. Group, i-butyl group, t-butyl group, and the like. Specifically, 1,2-Me ₂ Cp, 1,3-Me ₂ Cp, 1-Me-2-EtCp, 1- Me-2-nPrCp, 1-Me-2-nBuCp, 1-Me-3-EtCp, 1-Me-3-nPrCp, 1-Me-3-nBuCp, 1,2-Et ₂ Cp, 1,3- Et ₂ Cp, 1-Me-3-iPrCp, 1-Me-3-tBuCp and the like can be mentioned.

Specific examples of (iii) include those in which (R ¹ ) ₂ Cp is an indenyl group, an azulenyl group, a benzoindenyl group, a tetrahydroindenyl group, or a tetrahydroazurenyl group. These may further have a substituent.

Specific examples of (iv) include those in which (R ¹ ) ₄ Cp is a fluorenyl group or an octahydrofluorenyl group. These may further have a substituent.

Among the metallocene complexes represented by the general formulas (1) to (3), in the present invention, the molecular weight and melting point of the obtained ethylene polymer can be easily controlled within an appropriate range, A metallocene catalyst containing the metallocene complex represented by the general formula (1) is preferable from the viewpoint that a simple ethylene polymer can be obtained.
In addition, said metallocene complex may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and ratios.

2.2.2 Non-metallocene catalyst In the present invention, a non-metallocene catalyst, that is, an organic ligand that does not have a cyclopentadienyl group and coordinates to a metal ion with a heteroatom such as nitrogen, oxygen, or phosphorus. A single site catalyst having the complex as a catalyst component can also be used.

Specific examples of the metal complex used for such a nonmetallocene catalyst include the following (i) to (x).
(I) A ligand described in Japanese National Patent Publication No. 10-513289, that is, a nickel or palladium complex having α-diimine as a ligand (ii) Coordination described in Japanese Special Table 2001-512522 A nickel or palladium complex (iii) having an α-diimine ligand (iii) Grubbs et al. , Organomet. , 1998, 17, 3149, ie a nickel or palladium complex having phenoxyimine as a ligand (iv) a ligand described in Japanese Patent Application Laid-Open No. 11-315109, ie, phenoxyimine. Titanium, zirconium or hafnium complex (v) as ligand W. Coates et al. , J. et al. Am. Chem. Soc. , 2004, 126, 16326, that is, titanium, zirconium, hafnium, nickel, palladium complex (vi) having phenoxyketimine as a ligand (vi) C. Bazan et al. , Organomet. , 2005, 24, 5644, that is, a nickel or palladium complex having a ligand of α-iminocarboxamide (vii), a ligand described in US Patent Application Publication No. 2004/0220050, That is, a hafnium complex having pyridylamide as a ligand (viii) A ligand described in US Patent Application Publication No. 2007/0049712, that is, a nickel or palladium complex having phosphinosulfonic acid as a ligand ( ix) nickel or palladium complex having a ligand chelating with phosphorus and oxygen described in US Pat. No. 4,698,403 (x) chelating with phosphorus and oxygen described in Japanese Patent No. 45524335 Or palladium complexes with ligands located

Among these complexes, the complexes of (iv), (v), (vi), (vii), (viii), and (x) have relatively little short-chain branching represented by methyl branching, This is preferable because a highly crystalline ethylene polymer is easily obtained.
In addition, said metal complex may be used individually by 1 type, and may use 2 or more types together by arbitrary combinations and a ratio.

2.2.3 Cocatalyst The metallocene complex or nonmetallocene complex that can be used in the production of the ethylene polymer of the present invention may or may not have a polymerization catalyst function. When the complex does not have a polymerization catalyst function with respect to ethylene or α-olefin, a cocatalyst (sometimes referred to as an activator) for expressing the polymerization catalyst function can be used.

The cocatalyst is a catalyst that imparts a polymerization catalyst function for ethylene or α-olefin to the metallocene complex or nonmetallocene complex used in the production of the ethylene polymer of the present invention, that is, activates the complex. Although there is no particular limitation as long as it is present, specifically, it is preferable to use one or more substances selected from the group consisting of the following (A) to (D).
(A) Organoaluminum oxy compound (B) An ionic compound capable of reacting with the complex to exchange the component with a cation (C) Lewis acid (D) Ion exchange layered compound or inorganic except silicate Silicates Any of the above-mentioned cocatalysts (A) to (D) may be used alone, or two or more may be used in any combination and in any ratio. Two or more cocatalysts of (A) to (D) may be used in combination.

(A) Organoaluminum oxy compound In the present invention, an organoaluminum oxy compound can be used as a cocatalyst of a metallocene complex or a nonmetallocene complex. The organoaluminum oxy compound has Al—O—Al bonds in the molecule, and the number of bonds is usually in the range of 1 to 100, preferably 1 to 50.

Specific examples of the organoaluminum oxy compound include compounds represented by the following general formulas (4), (5), and (6).

In the general formulas (4) to (6), R ²² represents a hydrogen atom or a hydrocarbon group, preferably a hydrocarbon group having 1 to 10 carbon atoms, particularly preferably a hydrocarbon group having 1 to 6 carbon atoms. The plurality of R ²² may be the same or different. P represents an integer of 0 to 40, preferably 2 to 30.

The compounds represented by the general formulas (4) and (5) are also called aluminoxanes, and are obtained by reaction of one type of trialkylaluminum or two or more types of trialkylaluminum with water. In particular,
(A-1) methylaluminoxane, ethylaluminoxane, propylaluminoxane, butylaluminoxane, isobutylaluminoxane, obtained from one kind of trialkylaluminum and water,
(A-2) Methyl ethyl aluminoxane, methyl butyl aluminoxane, methyl isobutyl aluminoxane, etc. obtained from two types of trialkylaluminum and water.
Of these, methylaluminoxane and methylisobutylaluminoxane are preferred. A plurality of the above aluminoxanes can be used in combination. And said aluminoxane can be prepared on various conditions as well-known.

The compound represented by the general formula (6) is 10: 1 to 1: 1 (one type of trialkylaluminum or two or more types of trialkylaluminum and an alkylboronic acid represented by the following general formula (7). (Molar ratio) reaction. In the general formulas (6) and (7), R ²³ represents a hydrocarbon group or halogenated hydrocarbon group having 1 to 10 carbon atoms, preferably 1 to 6 carbon atoms.

R ²³ B (OH) ₂ (7)

Specifically, the following reaction product, that is,
(B-1) 2: 1 reaction product of trimethylaluminum and methylboronic acid,
(B-2) 2: 1 reaction product of triisobutylaluminum and methylboronic acid,
(B-3) a 1: 1: 1 reaction product of trimethylaluminum, triisobutylaluminum and methylboronic acid,
(B-4) 2: 1 reaction product of trimethylaluminum and ethylboronic acid,
(B-5) 2: 1 reaction product of triethylaluminum and butylboronic acid,
And so on.

Such an organoaluminum oxy compound is usually obtained by reacting an organoaluminum compound with water.
As the organoaluminum compound used for the preparation of the organoaluminum oxy compound, any of the compounds represented by the following general formula (8) can be used, but trialkylaluminum is preferably used.

(R ²⁴ ) _q Al (Q) _3-q (8)
Here, R ²⁴ represents a hydrocarbon group having 1 to 18 carbon atoms, preferably 1 to 12 carbon atoms, such as an alkyl group, an alkenyl group, an aryl group, or an aralkyl group. Q represents a hydrogen atom or a halogen atom, and q represents an integer of 1 to 3.

Specific examples of R ²⁴ include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, n-pentyl group, n-hexyl group, cyclohexyl group, n-octyl group, Examples thereof include an n-decyl group and an n-dodecyl group, and a methyl group or an isobutyl group is preferable, and a methyl group is particularly preferable.

Two or more of the above organoaluminum compounds can be mixed and used. The reaction ratio of water and the organoaluminum compound (water / Al molar ratio) is not particularly limited, but is usually 0.25 / 1 or more, preferably 0.5 / 1 or more, and usually 1.2 / 1. Hereinafter, it is preferably selected within a range of 1/1 or less.
The reaction temperature is not particularly limited, but is usually −70 ° C. or higher, preferably −20 ° C. or higher, and is usually selected within a range of 100 ° C. or lower, preferably 20 ° C. or lower.
Although reaction time is not specifically limited, Usually, 5 minutes or more, Preferably it is 10 minutes or more, and is 24 hours or less normally, Preferably it is chosen in 5 hours or less.

As water required for the reaction, not only mere water but also crystal water contained in copper sulfate hydrate, aluminum sulfate hydrate and the like, and components capable of generating water in the reaction system can be used.

An organoaluminum oxy compound obtained by reacting an alkylaluminum with water is usually called an alumoxane or an aluminoxane, and methylalumoxane (methylaluminoxane) is particularly suitable as the organoaluminum oxy compound. Furthermore, modified alumoxane in which a part of the methyl group of methylalumoxane is replaced with a different alkyl group such as isobutyl group, and modified alumoxane produced by reacting a modifying agent such as alcohol or phenol with methylalumoxane are also preferably used. Can do.

In addition, although alumoxane generally contains alkylaluminum used as a raw material as an impurity, alumoxane from which such alkylaluminum has been removed under reduced pressure can also be suitably used.

In the present invention, two or more of the above-described organoaluminum oxy compounds can be used in combination, and a solution in which the organoaluminum oxy compound is dissolved in the aforementioned inert hydrocarbon solvent or a dispersed dispersion is used. It can also be used. Furthermore, an organoaluminum compound can be brought into contact with or supported on a carrier usually used for an olefin polymerization catalyst such as silica, clay, or polymer carrier.

(B) An ionic compound capable of reacting with the complex to convert the component into a cation. Examples of such an ionic compound include compounds represented by the following general formula (9).
[CA] ^{e +} [AN] ^e- (9)

In the general formula (9), [CA] ^{e +} is a cation component, and examples thereof include a carbonium cation, a tropylium cation, an ammonium cation, an oxonium cation, a sulfonium cation, and a phosphonium cation. In addition, metal cations that are easily reduced by themselves, organic metal cations, and the like are also included.

Specific examples of the cation include triphenylcarbonium, diphenylcarbonium, cycloheptatrienium, indenium, triethylammonium, tripropylammonium, tributylammonium, N, N-dimethylanilinium, dipropylammonium, dicyclohexylammonium, Triphenylphosphonium, trimethylphosphonium, tris (dimethylphenyl) phosphonium, tris (dimethylphenyl) phosphonium, tris (methylphenyl) phosphonium, triphenylsulfonium, triphenylsulfonium, triphenyloxonium, triethyloxonium, pyrylium, silver ion, Gold ion, platinum ion, copper ion, palladium ion, mercury ion, ferrocenium ion, etc. That.

In the above general formula (9), [AN] ^e− is an anion component, which is a component (generally a non-coordinating component) that becomes a counter anion with respect to the cation species into which the transition metal compound is converted. Specific examples of the anion include an organic boron compound anion, an organic aluminum compound anion, an organic gallium compound anion, an organic arsenic compound anion, and an organic antimony compound anion.

Specific examples of the ionic compound capable of reacting with the complex and converting the component into a cation include the following compounds.

Tetraphenylboron, tetrakis (3,4,5-trifluorophenyl) boron, tetrakis {3,5-bis (trifluoromethyl) phenyl} boron, tetrakis {3,5-di (t-butyl) phenyl} boron, Boron compounds such as tetrakis (pentafluorophenyl) boron Tetraphenylaluminum, tetrakis (3,4,5-trifluorophenyl) aluminum, tetrakis {3,5-bis (trifluoromethyl) phenyl} aluminum, tetrakis {3,5 -Aluminum compounds such as di (t-butyl) phenyl} aluminum and tetrakis (pentafluorophenyl) aluminum Tetraphenylgallium, tetrakis (3,4,5-trifluorophenyl) gallium, tetrakis {3,5-bis (trifluoro) Methyl Phenyl} gallium, tetrakis {3,5-di (t-butyl) phenyl} gallium, gallium compounds such as tetrakis (pentafluorophenyl) gallium phosphorus compounds such as tetraphenylphosphorus, tetrakis (pentafluorophenyl) phosphorus tetraphenyl arsenic, Arsenic compounds such as tetrakis (pentafluorophenyl) arsenic Antimony compounds such as tetraphenylantimony and tetrakis (pentafluorophenyl) antimony Furthermore, decaborate, undecaborate, carbadodecaborate, decachlorodecaborate and the like can be mentioned.

(C) Lewis acid Examples of the Lewis acid capable of converting the complex into a cation include various organic boron compounds, metal halogen compounds, solid acids, and the like, and specific examples thereof include the following compounds.
Organoboron compounds such as triphenylboron, tris (3,5-difluorophenyl) boron, tris (pentafluorophenyl) boron Aluminum chloride, aluminum bromide, aluminum iodide, magnesium chloride, magnesium bromide, magnesium iodide, chloride Metal halides such as magnesium bromide, magnesium chloroiodide, magnesium bromoiodide, magnesium chloride hydride, magnesium chloride hydroxide, magnesium bromide hydroxide, magnesium chloride alkoxide, magnesium bromide alkoxide such as alumina, silica / alumina, etc. Solid acid etc.

(D) Ion exchange layered compound excluding silicate or inorganic silicate Ion exchange layered compound excluding silicate has a crystal structure in which planes formed by ionic bonds and the like are stacked in parallel with weak bonding force Is a compound that can exchange ions contained therein.

Examples of the ion-exchangeable layered compound excluding silicate include ion-crystalline compounds having a layered crystal structure such as hexagonal close-packed type, antimony type, CdCl ₂ type, CdI ₂ type, and the like. Specifically, α-Zr (HAsO ₄ ) · H ₂ O, α-Zr (HPO ₄ ) ₂ , α-Zr (KPO ₄ ) · 3H ₂ O, α-Ti (HPO ₄ ) ₂ , α-Ti (HAsO ₄ ) ₂ .H ₂ O, α-Sn (HPO ₄ ) ₂ .H ₂ O, γ-Zr (HPO ₄ ) ₂ , γ-Ti (HPO ₄ ) ₂ , γ-Ti (NH ₄ PO ₄ ) Examples thereof include crystalline acidic salts of polyvalent metals such as ₂ · H ₂ O.

Examples of the inorganic silicate include clay, clay mineral, zeolite, and diatomaceous earth. A synthetic product may be used for these, and the mineral produced naturally may be used.
Specific examples of clays and clay minerals include allophanes such as allophane, kaolins such as dickite, nacrite, kaolinite and anorcite, halloysites such as metahalloysite and halloysite, and serpentine such as chrysotile, lizardite and antigolite. Stone group, Montmorillonite, Sauconite, Beidellite, Nontronite, Saponite, Hectorite, etc. Examples include clay, gyrome clay, hysingelite, pyrophyllite, and ryokdeite group. These may form a mixed layer.

Examples of the artificial compound include synthetic mica, synthetic hectorite, synthetic saponite, and synthetic teniolite.
Among these specific examples, preferably, kaolins such as dickite, nacrite, kaolinite, anorcite, halosites such as metahalosite, halosite, chrysotile, lizardite, serpentine such as antigolite, montmorillonite, Smectites such as soconite, beidellite, nontronite, saponite, hectorite, vermiculite minerals such as vermiculite, mica minerals such as illite, sericite, sea chlorophyll, synthetic mica, synthetic hectorite, synthetic saponite, synthetic teniolite Particularly preferred are montmorillonite, sauconite, beidellite, nontronite, saponite, smectite such as hectorite, vermiculite mineral such as vermiculite, synthetic mica, synthetic hectorite, synthetic saponite, synthetic Taeniolite.

These ion-exchange layered compounds excluding silicates or inorganic silicates may be used as they are, but acid treatment with hydrochloric acid, nitric acid, sulfuric acid, etc., and LiCl, NaCl, KCl, CaCl ₂ , MgCl ₂ , Li ₂ SO ₄ , MgSO ₄ , ZnSO ₄ , Ti (SO ₄ ) ₂ , Zr (SO ₄ ) ₂ , Al ₂ (SO ₄ ) _3, etc. are preferably used after performing at least one treatment. . In the treatment, the corresponding acid and base may be mixed to produce a salt in the reaction system. In addition, shape control such as pulverization and granulation may be performed, and granulation is preferable in order to obtain a solid catalyst component having excellent particle fluidity. The above components are usually used after being dehydrated and dried.

2.2.4 Optional component 2.2.4.1 Fine particle carrier A fine particle carrier may coexist as an optional component of the single site catalyst.
The fine particle carrier is composed of an inorganic or organic compound, and its size is not particularly limited, but is usually 5 μm or more, preferably 10 μm or more, and a fine particle carrier having a particle size of usually 5 mm or less, preferably 2 mm or less. It is.

Examples of inorganic carriers include metal oxides such as SiO ₂ , Al ₂ O ₃ , MgO, ZrO, TiO ₂ , B ₂ O ₃ , ZnO, SiO ₂ —MgO, SiO ₂ —Al ₂ O ₃ , SiO ₂ —. Examples thereof include composite metal oxides such as TiO ₂ , SiO ₂ —Cr ₂ O ₃ , SiO ₂ —Al ₂ O ₃ —MgO.

The specific surface area of these carriers is not particularly limited, but is usually 20 m ³ / g or more, preferably 50 m ³ / g or more, and usually 1,000 m ³ / g or less, preferably 700 m ³ / g or less.
The pore volume of the carrier is not particularly limited, but is usually 0.1 cm ² / g or more, preferably 0.3 cm ² / g or more, more preferably 0.8 cm ² / g or more.

Examples of the organic carrier include polymers of α-olefins having 2 to 14 carbon atoms such as ethylene, propylene, 1-butene, 4-methyl-1-pentene (including polymers and copolymers), styrene, divinyl Examples include porous polymer fine particle carriers made of polymers such as benzene and other aromatic unsaturated hydrocarbons (including polymers and copolymers).

2.2.4.2 Organoaluminum compound In the present invention, an organoaluminum compound may also be present as a co-catalyst for the single site catalyst.
The co-catalyst organoaluminum compound is AlR ²⁵ _r Z _3-r (wherein R ²⁵ represents a hydrocarbon group having 1 to 20 carbon atoms, Z represents a hydrogen atom, a halogen atom, an alkoxy group or an aryloxy group) , R is an integer of 1 ≦ r ≦ 3).

Specifically, trialkylaluminum such as trimethylaluminum, triethylaluminum, tripropylaluminum, triisobutylaluminum, halogen aluminum or alkoxy group-containing alkylaluminum such as diethylaluminum monochloride, diethylaluminum ethoxide, diethylaluminum hydride, diisobutylaluminum Examples include hydrogen atom-containing organoaluminum compounds such as hydride. In addition, aluminoxane such as methylaluminoxane can also be used. Of these, trialkylaluminum is particularly preferred.

These optional components may be used in combination of two or more. Moreover, you may add this arbitrary component newly after superposition | polymerization start.

3. Method for Producing Olefin Polymerization Catalyst The single site catalyst used in the production of the ethylene polymer in the present invention comprises a transition metal compound constituting the single site catalyst, and optional components such as a cocatalyst and / or a cocatalyst as necessary. Although it is obtained by contacting, there is no particular limitation on the contact method. This contact may be performed not only during the catalyst preparation but also during the prepolymerization or polymerization of the monomer.

Further, the fine particle carrier may be allowed to coexist or contact when the catalyst components are in contact with each other or after the contact.

The above contact may be carried out in an inert gas such as nitrogen or in an inert hydrocarbon solvent such as pentane, hexane, heptane, toluene, xylene. These solvents are preferably used after an operation for removing poisoning substances such as water and sulfur compounds. The contact temperature is usually −20 ° C. or higher and not higher than the boiling point of the solvent to be used, and it is particularly preferably performed between room temperature (about 20 ° C.) and the boiling point of the solvent to be used.

There are no particular restrictions on the ratio of each catalyst component used, but there is no particular limitation when using an ion-exchange layered compound or inorganic silicate excluding silicate as the cocatalyst component or when using the above-mentioned fine particle carrier. However, the transition metal compound is usually 0.0001 mmol or more, preferably 0.001 mmol or more, usually 10 mmol or less, preferably 5 mmol or less per 1 g of the cocatalyst component or fine particle support. When an organoaluminum compound as an optional component or an organoaluminum oxy compound as a cocatalyst is used, the transition metal compound is usually 0 mmol or more, preferably 0.01 mmol or more, usually 10, per gram of these components. By setting it to be 000 mmol or less, preferably 100 mmol or less, a favorable result can be obtained in terms of polymerization activity.

Further, although not particularly limited, the atomic ratio of the transition metal in the transition metal compound and the aluminum in the organoaluminum compound as an optional component or the organoaluminum oxy compound as a cocatalyst is usually 1: 0 or more, preferably 1: 0. .1 or more, usually 1: 1,000,000 or less, preferably 1: 100,000 or less, similarly from the viewpoint of polymerization activity and the like.

The catalyst thus obtained may be used after washing with an inert hydrocarbon solvent such as n-pentane, n-hexane, n-heptane, toluene, xylene, or may be used without washing. Good.
At the time of washing, a new combination of the above-described organoaluminum compound or organoaluminum oxy compound may be used as necessary. The amount of the organoaluminum compound or organoaluminum oxy compound used at this time is 1: 0 to 10,000 in terms of the atomic ratio of the aluminum in the organoaluminum compound or the organoaluminum oxy compound to the transition metal in the transition metal compound. Is preferable.

4). 4. Polymerization reaction 4.1 Solvent The polymerization reaction for producing the ethylene polymer of the present invention includes hydrocarbons such as propane, n-butane, isobutane, n-hexane, n-heptane, toluene, xylene, cyclohexane and methylcyclohexane. Liquid such as solvent or liquefied α-olefin, or polar solvent such as diethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, dioxane, ethyl acetate, methyl benzoate, acetone, methyl ethyl ketone, formamide, acetonitrile, methanol, isopropyl alcohol, ethylene glycol Performed in the presence or absence. Moreover, you may use the mixture of the liquid compound described here as a solvent. In order to obtain an ethylene polymer having a high polymerization activity and a high molecular weight, it is preferable to use the above hydrocarbon solvent.

4.2 Amount of catalyst used The amount of the single-site catalyst used in the production of the ethylene polymer of the present invention is not particularly limited as long as the desired polymerization reaction proceeds smoothly. The catalyst-derived metal content is preferably 10,000 to 0.1 ppm by weight, particularly 1,000 to 0.1 ppm by weight, based on the polymer weight.

4.3 Polymerization format There is no particular limitation on the polymerization format when producing the ethylene-based polymer of the present invention, and slurry polymerization in which at least a part of the produced polymer in the medium becomes a slurry, and the liquefied monomer itself is used as the medium. Bulk polymerization, gas phase polymerization performed in a vaporized monomer, or high pressure ion polymerization in which at least a part of the produced polymer is dissolved in a monomer liquefied at high temperature and high pressure are preferably used. Further, any of batch polymerization, semi-batch polymerization, and continuous polymerization may be used. Moreover, living polymerization may be sufficient and superposition | polymerization may be performed, combining chain transfer.

There are no particular restrictions on the supply of catalyst and monomer to the polymerization reactor, and various supply methods can be used depending on the purpose. For example, in the case of batch polymerization, it is possible to take a technique in which a predetermined amount of monomer is supplied to a polymerization reactor in advance and a catalyst is supplied thereto. In this case, an additional monomer or an additional catalyst may be supplied to the polymerization reactor. In the case of continuous polymerization, a method in which a predetermined amount of monomer and catalyst are continuously or intermittently supplied to the polymerization reactor to continuously perform the polymerization reaction may be employed.

The unreacted monomer and medium may be separated from the produced polymer and recycled. In recycling, these monomers and media may be purified and reused, or may be reused without purification. A conventionally known method can be used for separating the produced polymer from the unreacted monomer and the medium. For example, methods such as filtration, centrifugation, solvent extraction, and reprecipitation using a poor solvent can be used.

4.4 Polymerization Conditions There are no particular restrictions on the polymerization temperature, polymerization pressure and polymerization time when producing the ethylene polymer of the present invention, but usually considering the productivity and process capability from the following ranges, Optimal settings can be made.
The polymerization temperature is not particularly limited, but is usually −20 ° C. or higher, preferably 0 ° C. or higher, usually 290 ° C. or lower, preferably 250 ° C. or lower.
The polymerization pressure is not particularly limited, but is usually 0.1 MPa or more, preferably 0.3 MPa or more, usually 100 MPa or less, preferably 90 MPa or less.
The polymerization time is not particularly limited, but is usually 0.1 minutes or more, preferably 0.5 minutes or more, more preferably 1 minute or more, usually 10 hours or less, preferably 7 hours or less, more preferably 6 hours or less. You can choose.

In the present invention, the polymerization is usually carried out in an inert gas atmosphere. As the inert gas, for example, nitrogen, argon, carbon dioxide atmosphere can be used, and nitrogen atmosphere is preferably used. Note that a small amount of oxygen or air may be mixed in the atmosphere.

4.5 Composition Control Regarding the control of the copolymer composition of the resulting ethylene-based polymer, a method of controlling by supplying a plurality of monomers to the reactor and changing the supply ratio can be generally used. In addition, there are a method of controlling the copolymer composition using the difference in the monomer reactivity ratio due to the difference in the structure of the catalyst, and a method of controlling the copolymer composition using the polymerization temperature dependence of the monomer reactivity ratio. .

4.6 Molecular Weight Adjustment Method Conventionally known methods can be used to control the molecular weight of the resulting ethylene polymer. That is, a method for controlling the molecular weight by controlling the polymerization temperature, a method for controlling the molecular weight by controlling the monomer concentration, a method for controlling the molecular weight by using a chain transfer agent, and a ligand structure in a transition metal complex of a single site catalyst. And a method of controlling the molecular weight by controlling. When a chain transfer agent is used, a conventionally known chain transfer agent can be used. For example, hydrogen, metal alkyl, etc. can be used.

Also, various cross-linking reactions are known as methods for increasing the molecular weight of the polymer in the molding process. For example, it is known that when a peroxide is used or various types of radiation are applied, a crosslinking reaction by a radical mechanism proceeds and the molecular weight of the resulting polymer increases.

4.7 Adjustment Method of Melting Point Conventionally known methods can be used to control the melting point of the resulting ethylene polymer. That is, a method for controlling the polymerization temperature, a method for controlling the monomer concentration, a method for controlling the amount of short chain branching by controlling the ligand structure in the transition metal complex of the single site catalyst, and the like.

4.8 Method for adjusting sand / rubber wheel wear performance The sand / rubber wheel wear performance of the resulting ethylene polymer is closely related to the weight average molecular weight, molecular weight distribution, melting point, and crystallinity of the ethylene polymer. Yes. In order to exhibit excellent wear resistance, it is preferable that the weight average molecular weight is high, the molecular weight distribution is desirably narrow, the melting point is desirably high, and the crystallinity is preferably high. Among these factors, the weight average molecular weight, molecular weight distribution, and melting point of the ethylene polymer are mainly determined in the polymerization process, and the control method thereof is as described above. Crystallinity is determined in the molding process. Generally, it is possible to increase the crystallinity by slowing the heat removal rate after thermoforming. Similarly, a technique for increasing the crystallinity by performing an annealing treatment after molding is also known.

[Ethylene-based resin composition for producing wear-resistant resin molded article]
The ethylene-based resin composition for producing an abrasion-resistant resin molded body of the present invention (hereinafter sometimes referred to as “the ethylene-based resin composition of the present invention”) is one kind of the above-described ethylene-based polymer of the present invention. Or it manufactures by mix | blending various additives with two or more types as needed.

That is, in the present invention, an antistatic agent, an antioxidant, and an antioxidant according to the use of the molded body, within a range that does not impair the object of the present invention to achieve both the melt fluidity and the sand / rubber wheel wear performance. Known additives such as neutralizers, lubricants, anti-blocking agents, anti-fogging agents, organic or inorganic pigments, fillers, inorganic fillers, UV degradation inhibitors, dispersants, weathering agents, crosslinking agents, foaming agents, flame retardants, etc. An agent can be blended.
Further, a nucleating agent, glass fiber, aramid fiber, carbon fiber, cellulose fiber, carbon black, rubber, other resin other than the ethylene polymer of the present invention may be blended.

In particular, the ethylene resin composition of the present invention contains a long-chain fatty acid metal salt such as calcium stearate, magnesium stearate, zinc stearate, barium stearate, calcium laurate, barium laurate, zinc laurate, calcium ricinoleate, etc. It is preferable to blend as a lubricant or a release agent. One of these lubricants or mold release agents may be used alone, or two or more thereof may be used in any combination and ratio.

When the ethylene resin composition of the present invention contains a lubricant or mold release agent such as calcium stearate, the content thereof is 10 to 0.01 parts by weight, particularly 5 parts per 100 parts by weight of the ethylene polymer of the present invention. The amount is preferably 0.01 parts by weight. If the amount used is too small, the above-mentioned effect due to the use of a lubricant or mold release agent cannot be obtained sufficiently, and if it is too large, the mechanical properties of the resin may be impaired.

In addition, when the ethylene polymer and the ethylene resin composition of the present invention are melt-processed in the presence of an organic peroxide, the cross-linking reaction is advanced to increase the molecular weight of the ethylene polymer, and sand / rubber wheel wear Since performance can be improved, the ethylene-based resin composition of the present invention may contain an organic peroxide.

The organic peroxide that can be contained in the ethylene-based resin composition of the present invention is not particularly limited, and examples thereof include di-t-butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, 2,5 -Dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2,5-di (t-butylperoxy) hexyne-3,1,3-bis (t-butylperoxy) Isopropyl) benzene, dialkyl peroxides such as 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, t-butylperoxybenzoate, t-butylperoxyisopropyl carbonate, 2,5 -Dimethyl-2,5-di (benzoylperoxy) hexane, 2,5-dimethyl-2,5-di (benzoylperoxy) hexyne-3, etc. Peroxyesters, acetyl peroxide, lauroyl peroxide, benzoyl peroxide, p-chlorobenzoyl peroxide, diacyl peroxides such as 2,4-dichlorobenzoyl peroxide, hydroperoxides such as diisopropylbenzene hydroperoxide Etc. Of these, those having a one-minute half-life temperature of 140 ° C. or more are preferred, for example, 2,5-dimethyl-2,5-di (t-butylperoxy) hexane, 2,5-dimethyl-2 , 5-di (t-butylperoxy) hexyne-3 and the like are preferable. These organic peroxides may be used alone or in combination of two or more in any combination and ratio.

Further, a crosslinking aid may be used together with the organic peroxide as necessary. Examples of the crosslinking aid that can be used in combination with the organic peroxide include sulfur, p-quinonedioxime, and p-dinitrosobenzene. , Peroxide crosslinking aids such as 1,3-diphenylguanidine and m-phenylenebismaleimide, polyfunctional vinyl compounds such as divinylbenzene, triallyl cyanurate, triallyl isocyanurate and diallyl phthalate, ethylene glycol di (meth) Examples thereof include polyfunctional (meth) acrylate compounds such as acrylate, diethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, and allyl (meth) acrylate.
These crosslinking aids may be used alone or in combination of two or more in any combination and ratio.

In order to prevent oxidative degradation during melt processing, an antioxidant may be present. Examples of the antioxidant include 2,4-dimethyl-6-tert-butylphenol, 2,6-di- t-butylphenol, 2,6-di-t-butyl-p-cresol, 2,6-di-t-butyl-4-ethylphenol, 2,4,6-tri-t-butylphenol, 2,5-di -T-butylhydroquinone, butylated hydroxyanisole, n-octadecyl-3- (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate, stearyl-β- (3,5-di-t Monophenols such as -butyl-4-hydroxyphenyl) propionate, 4,4'-dihydroxydiphenyl, 2,2'-methylenebis (4-methyl-6-t-butylphenone) ), 2,2′-methylenebis (4-ethyl-6-tert-butylphenol), 4,4′-methylenebis (2,6-di-tert-butylphenol), 4,4′-butylidenebis (3-methyl-6) -T-butylphenol), 2,6-bis (2′-hydroxy-3′-t-butyl-5′-methylbenzyl) -4-methylphenol, and the like, 1,1,3-tris (2 ′ -Methyl-4'-hydroxy-5'-t-butylphenyl) butane, 1,3,5-trimethyl-2,4,6-tris (3 ', 5'-di-t-butyl-4'-hydroxy Benzyl) benzene, tris (3,5-di-t-butyl-4-hydroxyphenyl) isocyanurate, tris [β- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxyethyl] Tri- or higher polyphenols such as socyanurate, tetrakis [methylene-3- (3 ′, 5′-di-t-butyl-4′-hydroxyphenyl) propionate] methane, 2,2′-thiobis (4-methyl-6) -T-butylphenol), 4,4'-thiobis (2-methyl-6-t-butylphenol), 4,4'-thiobis (3-methyl-6-t-butylphenol) and the like, aldol-α Naphthylamines such as naphthylamine, phenyl-α-naphthylamine and phenyl-β-naphthylamine, diphenylamines such as p-isopropoxydiphenylamine, N, N′-diphenyl-p-phenylenediamine, N, N′-di-β- Naphthyl-p-phenylenediamine, N-cyclohexyl-N′-phenyl-p-phen Examples thereof include phenylenediamine-based compounds such as nylenediamine, N-isopropyl-N′-phenyl-p-phenylenediamine, and the like, among which monophenol-based, bisphenol-based, tri- or higher polyphenol-based, thiobisphenol-based, and the like are preferable. These antioxidants may be used alone or in combination of two or more in any combination and ratio.

When the above-described organic peroxide is used, the organic peroxide is preferably used in an amount of 0.1 to 10 parts by weight, particularly 0.1 to 2 parts by weight, based on 100 parts by weight of the ethylene polymer of the present invention. If the amount of the organic peroxide used is too small, it will not be possible to sufficiently obtain a high molecular weight due to the use of the organic peroxide. The appearance of the molded product may be adversely affected.

Further, when the above-mentioned crosslinking aid is used, the crosslinking aid is preferably used in an amount of 1 to 200 parts by weight, particularly 10 to 100 parts by weight, per 100 parts by weight of the organic peroxide. If the amount of the crosslinking aid used is too small, the effect of promoting the crosslinking reaction due to the use of the crosslinking aid cannot be sufficiently obtained, and if too much, resin molding such as coloring or odor due to the remaining unreacted crosslinking aid. Body quality defects may be unacceptable.

Further, when the above-mentioned antioxidant is used, the antioxidant is preferably used in an amount of 10 to 0.01 parts by weight, particularly 5 to 0.01 parts by weight, based on 100 parts by weight of the ethylene polymer of the present invention. If the amount of antioxidant used is too small, the effect of preventing oxidative deterioration due to the use of antioxidant cannot be obtained sufficiently, and if too much, bleeding out causes deterioration of the appearance of processing molding machines and resin moldings. Connected.

In the ethylene resin composition of the present invention, one type of the ethylene polymer of the present invention may be used, or two or more types of the ethylene polymer of the present invention may be mixed and used. When two or more types of ethylene polymers are used, two or more types of ethylene polymers polymerized by changing the monomer and polymerization conditions using the same catalyst may be used, or polymerization is performed using different catalysts. Two or more types of ethylene polymers may be used. Two or more ethylene polymers having different molecular weights, melting points, presence / absence of copolymerization components, and copolymerization compositions may be used.
When the ethylene resin composition of the present invention contains two or more kinds of the ethylene polymer of the present invention, the physical properties of the ethylene polymer in the ethylene resin composition of the present invention are those two or more kinds. The ethylene polymer in the ethylene resin composition contains an ethylene polymer that does not satisfy the physical properties of the ethylene polymer of the present invention. However, the ethylene polymer as a mixture may satisfy the physical properties of the ethylene polymer of the present invention.

When blending an additive into an ethylene polymer, it is usual to physically blend the additive with the ethylene polymer using a mixer, mill, extruder, etc. A solution blend in which a polymer is dissolved and an additive is added to the ethylene polymer solution may be used. In addition, you may make it mix | blend an additive by manufacturing an ethylene-type polymer in presence of an additive.

In the present invention, since the ethylene-based polymer of the present invention has melt fluidity, the blending of the additive is extremely easy as compared with the conventional ultrahigh molecular weight polyethylene, and it was obtained by blending the additive. One of the advantages of the present invention is that a desired function can be easily imparted to the ethylene-based resin composition.

The ethylene resin composition of the present invention may be a powder maintaining the powder shape of the original ethylene polymer, or may be a pulverized powder, or using an extruder. Pellets produced using a granulation step may be used.

The ethylene-based resin composition of the present invention exhibits a wear resistance of 0.035 cm ³ or more and 0.24 cm ³ or less in a sand / rubber hole wear test. When the sand / rubber wheel wear performance exceeds the above upper limit, the wear resistance is not sufficient for practical use, and when it is less than the lower limit, the workability may be lowered. The lower limit of the sand / rubber wheel wear performance of the ethylene-based resin composition of the present invention is preferably 0.04 cm ³ and the upper limit is preferably 0.20 cm ³ .

The sand / rubber wheel wear performance of the ethylene resin composition of the present invention is described in the Examples section below from a press piece obtained by press molding using the ethylene resin composition of the present invention. The test piece for the sand / rubber wheel wear test is prepared by the following method, and the test is performed by performing a sand / rubber wheel wear test on the test piece by the method described in the example section below. it can.

The other physical properties of the ethylene resin composition of the present invention usually have physical properties similar to the physical properties of the ethylene polymer of the present invention, but can be appropriately adjusted depending on the components added depending on the purpose of use and the like.

[Manufacture of wear-resistant resin moldings]
Since the ethylene-based polymer of the present invention and the ethylene-based resin composition of the present invention in which an additive is blended with the ethylene-based polymer of the present invention have melt fluidity, a conventionally known molding method used for thermoplastic polymers is used. It can be used to produce a molded body. In these molding methods, the ethylene polymer or ethylene resin composition is heated to a temperature equal to or higher than the melting point of the ethylene polymer, and after the ethylene polymer or ethylene resin composition is in a molten state, a desired state is obtained. Mold to shape. As for the molding method, an optimal molding method is selected from the viewpoint of the purpose of using the molded body and the productivity.

Specific molding methods include injection molding, transfer molding, blow molding, injection blow molding, extrusion blow molding, melt compression molding, melt extrusion molding, melt spinning molding, melt coating, melt bonding, melt rotation molding, foam molding, and the like. Is mentioned.

In particular, in the melt molding of the ethylene polymer or the ethylene resin composition of the present invention, as described above, the presence of an organic peroxide increases the molecular weight of the ethylene polymer to further increase the sand / rubber wheel. A molded article having excellent wear performance can be obtained, which is preferable.

A feature of the present invention is that a molded body having excellent sand / rubber wheel wear performance is obtained by a conventionally known melt molding method, and thus is excellent in productivity. A molding method for polyethylene may be applied. Specifically, ram extrusion, compression molding, sintering, machining, skiving, high hydrostatic pressure processing, solution method, gel method and the like may be used.

Further, the molded body obtained by such a molding method may be subjected to secondary processing by a molding method such as vacuum molding, uniaxial stretching, biaxial stretching, polishing, and cutting. Furthermore, treatments such as annealing, heat treatment, rapid cooling, and chemical treatment may be added.

Thus, by molding the ethylene-based polymer of the present invention or the ethylene-based resin composition of the present invention, the sand / rubber measured by the sand / rubber wheel abrasion test described in the section of Examples below. wheel wear performance 0.035Cm ³ or 0.24 cm ³ or less, preferably to obtain a wear-resistant resin molded article of the present invention which is a 0.040 cm ³ or more 0.16 cm ³ or less.

[Uses of wear-resistant resin moldings]
The wear-resistant resin molded article of the present invention obtained from the ethylene polymer of the present invention or the ethylene resin composition of the present invention can be applied to applications where commercially available ultra-high molecular weight polyethylene is used, Specifically, wires, cables, printed circuit boards, semiconductors, automotive parts, outdoor products, food industry products, biomedical intermediates or products such as artificial hip joints, artificial shoulder joints, artificial spines, artificial knee joints, artificial elbows Artificial graft tissue members such as joints, artificial ankle joints, artificial finger joints, artificial graft tissue pieces, orthopedic graft tissue pieces, composite materials, monofilament fibers, multifilament fibers, oriented or non-oriented fibers, hollow, woven or non-woven fabrics, Filter, membrane, film, sheet, plate, block, rod, round bar, multilayer film, multi-component film, barrier film, primary or secondary Battery separator films for ponds (eg lithium ion batteries), containers, bags, bottles, containers, tubes, hoses, pipes, valves, O-rings, columns, tanks, fittings, gaskets, heat exchangers, injection molded products, The present invention can be applied to T-die molded products, heat-sealable packing profiles, heat-shrinkable films, thermoplastic joint parts, blow-molded parts, ram extruded parts, screw extruded profiles, and the like.

Examples of applications for various other intermediates and wear-resistant products for end users include gas house filtration bags, doctor blades, profiles, ski soles, snowboard soles, snowmobile runners, particulate additives for coating, Hose lining, hopper lining, chute lining, steel pipe coating, protective coating, electrostatic coating, wire coating, optical fiber coating, container lining and internal components, tanks, columns, pipes, fittings, pumps, pump housings, Valves, valve seats, beverage dispenser tubes and fittings, fittings, seals, containers, bags, bottles, hoses, tubes, industrial parts, gears, cams, sliders, levers, arms, clutches, pulleys, rollers, rollers, key stems ,Key , Shutters, reels, washers, pistons, cylinders, guide rails, shafts, bearings, ball bearings, screws, nails, nuts, bolts, heat exchangers, tape guides, sliding parts (mechanical parts) in printing equipment, home appliances Examples include sliding parts in products, sliding parts in automobile steering devices and steel cable guides, sliding parts in conveyor devices, and sliding parts in elevators and escalators.

Hereinafter, the present invention will be described in more detail with reference to synthesis examples, examples and comparative examples. However, the present invention is not limited by the following examples unless it exceeds the gist.

[Method of measuring weight average molecular weight Mw, number average molecular weight Mn]
Mw and Mn were measured by the following method using gel permeation chromatography (GPC).
・ Measuring device: GPCV2000 (with detector RI detector) (manufactured by Waters)
・ Detection wavelength: 598nm
・ Column: TSKgelGMH-HT (30cm x 4) (manufactured by Tosoh Corporation)
・ Pretreatment equipment: Pretreatment equipment for high temperature GPC PL-SP260VS (manufactured by Polymer Laboratory)
Measurement conditions: Sample solution injection amount: about 520 ml
Column temperature: 135 ° C
Solvent: o-dichlorobenzene Flow rate: 1.0 ml / min
Sample pretreatment conditions About 20 mg of sample was collected in the vial for the pretreatment device, and o-dichlorobenzene (BHT concentration = 0.5 g / L) containing BHT (butylhydroxytoluene) as a stabilizer was added. The polymer concentration was adjusted to 0.1% by weight. The polymer was dissolved by heating to 135 ° C. in the pretreatment apparatus, and then filtered using a glass filter to prepare a sample.
・ Molecular weight calculation method Using a commercially available monodispersed polystyrene as a standard sample, create a calibration curve for retention time and molecular weight from the viscosity formula of the polystyrene standard sample and ethylene polymer, and calculate the molecular weight based on the calibration curve. Calculation was performed.
As the viscosity formula used for the calculation, [η] = K × Mα is used, and for polystyrene, K = 1.38 × 10 ⁻⁴ and α = 0.70 are used. For this, K = 4.77 × 10 ⁻⁴ and α = 0.70 were used.

[Measurement method of fluidity (MFR, HMFR)]
It measured based on JIS specification and JIS7210 (1999).
・ Measuring equipment: MX-101-B manufactured by Takara Kogyo Co., Ltd.
・ Load: MFR 2.16kg, HMFR 21.6kg

[Measuring method of melting point Tm]
The melting point Tm was determined by the following DSC measurement.
-Measuring device: PYRIS Diamond DSC differential scanning calorimeter (manufactured by PerkinElmer)
·Measurement condition:
About 5 mg of sample was melted at 210 ° C. for 5 minutes, cooled to −20 ° C. at a cooling rate of 10 ° C./minute, held at −20 ° C. for 5 minutes, and then heated to 210 ° C. at a heating rate of 10 ° C./minute. To obtain a melting curve. The peak top temperature of the main endothermic peak in the final temperature increase stage performed to obtain the melting curve was defined as the melting point Tm.

[How to make a specimen for wear test]
The mass of the ethylene polymer to be evaluated was 100 parts, 0.05 part of calcium stearate was added as an additive, and a resin composition was prepared by dry blending. A press piece was prepared by press molding using the obtained resin composition. During pressing, after heating at 165.5 ° C. for 45 minutes, it was cooled for 35 minutes. The press pressure was 3.24 MPa. Using the obtained press pieces, the following test pieces for sand / rubber wheel wear test and, if necessary, test pieces for sand slurry wear test were prepared, and the wear test was performed.

[Sand / Wheel Abrasion Test]
The sand / rubber wheel abrasion test was performed in accordance with ASTM (American Society For Testing and Materials) standard, ASTM G65. That is, the sand / rubber wheel wear test is a test method defined by ASTM G65, and a sand / rubber wheel wear tester that satisfies the standard is used.
Measuring device: CSI- # 227 manufactured by Custom Scientific Instruments
・ Test sand: 50-70 sand size made by American Foundry Sand Co., Ltd. Adjusted to a particle size distribution ranging from about 50 mesh (300 μm) to 70 mesh (212 μm), and satisfying the following specifications. .
Specification of sand: 95% by weight or more of sand having a particle size of 212 μm or more and less than 300 μm, and 5% by weight or less of sand having a particle size of 300 μm or more and less than 425 μm.
・ Measurement sample:
A test piece of 0.25 inch × 1.00 inch × 3.00 inch was prepared from the above-mentioned press piece using a band saw.
· Measuring method:
Test sand (22.7 kg) was placed in the hopper of a sand / rubber wheel abrasion tester. After measuring the mass (g) of the test piece, the test piece was fixed to a fixing jig of a sand / rubber wheel abrasion tester, and the rubber wheel was rotated at 200 rpm while flowing the test sand at 300 g / min. Was pressed against the rubber wheel with a load of 30 pounds. The test was terminated when the rubber wheel rotated 3200 times.
The test piece was removed from the fixing jig, and the sand adhering to the test piece surface was wiped off. Subsequently, the mass (g) of the test piece was measured. The mass reduction amount (g) of the test piece due to wear was calculated, and the loss volume (cm ³ ) due to wear was obtained by dividing the mass reduction amount (g) by the density (g / cm ³ ) of the test piece.
In the present invention, the loss volume (cm ³ ) obtained by this method is referred to as sand / rubber wheel wear performance (SWA, Sand Wheel Ablation).

[Sand Slurry Abrasion Test]
The sand slurry wear test was performed using a measuring device conforming to ASTM D4020 in accordance with ASTM standards and ASTM D4020.
・ Test Alumina: Made by American Foundry Sand Co., Ltd. 50-70 Test alumina particle size is adjusted in the range of about 50 mesh (300 μm) to 70 mesh (212 μm) and adjusted to a particle size distribution satisfying the following specifications. .
・ Specifications of alumina: Alumina with a particle size of 212 μm or more and less than 300 μm is 95% by weight or more, and alumina with a particle size of 300 μm or more and less than 425 μm is 5% or less.
A test piece of 0.250 inch × 1.000 inch × 2.750 inch was prepared by cutting from the above-mentioned press piece. Drill a 11/32 inch hole in the center of the resulting specimen and drill another 9/64 inch hole about 1/8 inch away from the hole. did.
· Measuring method:
The mass (g) of the test piece was measured, the cut surface of the test piece was turned up, and the test piece was fixed to the apparatus with a bolt through a 11/32 inch hole opened in the center. Next, the pin protruding from the shaft was passed through a 9/64 inch hole to determine the mounting angle of the test piece.
Test alumina (450 g) was weighed and poured into a cup. Next, 300 g of water was measured and added to the cup to form a water / alumina slurry. The cup containing the water / alumina slurry was fixed to the apparatus, and the test piece was completely immersed in the slurry.
The shaft and the test piece were rotated at 1750 rpm for 120 minutes while operating the chiller unit and maintaining the temperature at 23 ° C. ± 2 ° C. After completion, the test piece was removed from the apparatus, and water and alumina remaining on the surface of the test piece were wiped off and then dried. After confirming that the water was completely dried, the mass (g) of the test piece was measured, and the mass reduction amount (g) of the test piece due to wear was calculated. Finally, the mass loss (g) was divided by the density (g / cm ³ ) of the test piece to determine the loss volume (cm ³ ) due to wear.
In the present invention, the loss volume (cm ³ ) obtained by this method is referred to as sand slurry abrasion resistance (Sand Slurry Ablation).

[Catalyst synthesis, ethylene polymer production]
In the following catalyst synthesis and ethylene polymer production, unless otherwise specified, the operation was performed in a purified nitrogen atmosphere, and the solvent and polymerization monomer were dehydrated and deoxygenated.
Further, ethylene polymerization or ethylene / 1-hexene copolymerization was performed according to the following procedure.
An autoclave with an induction stirring blade having an internal volume of 2 L was charged with n-hexane as a solvent and an organoaluminum compound as a scavenger. When copolymerizing with 1-hexene, a predetermined amount of 1-hexene was charged into the autoclave at this point. Next, the catalyst was charged into the catalyst feeder attached to the autoclave. The gas phase part of the autoclave was replaced with ethylene three times, and the temperature was raised to a predetermined polymerization temperature. When the temperature reached a predetermined temperature, the catalyst was supplied into the autoclave, and ethylene was continuously supplied up to the predetermined pressure. The time when the internal pressure reached the predetermined pressure was set as the polymerization start time, and polymerization was carried out for a predetermined time under the constant temperature and pressure conditions. In some cases, hydrogen was fed to the autoclave for molecular weight control. In that case, a predetermined amount of hydrogen was supplied to the autoclave before supplying the catalyst so that a predetermined hydrogen concentration was maintained during the polymerization, and further, ethylene containing a predetermined concentration of hydrogen was supplied during the polymerization. After polymerization for a predetermined time, the unreacted monomer was purged to terminate the polymerization. The ethylene polymer slurry was collected, the organic solvent was filtered off, and the resulting ethylene polymer powder was dried. Details are shown in each synthesis example.

<Synthesis Example 1>
In a 500 mL three-necked flask, silica gel (2 g) having an average particle size of 50 microns as a carrier, toluene (10 mL) as a solvent, and dichlorobis (n-butylcyclopentadienyl) hafnium (hereinafter abbreviated as BCH) as a metallocene complex ( 0.05 mmol, manufactured by Aldrich) and methylaluminoxane (hereinafter abbreviated as MAO) (PMAO manufactured by Tosoh Finechem) (10 mmol) were sequentially added as a cocatalyst and stirred at 60 ° C. for 1 hour. All the solvents were removed under reduced pressure to obtain silica gel-supported metallocene catalyst A.

<Synthesis Example 2>
A catalyst B was obtained in the same manner as in Synthesis Example 1 except that the metallocene complex was changed from BCH to dichlorobis (n-butylcyclopentadienyl) zirconium (hereinafter abbreviated as BCZ) (manufactured by Aldrich).

<Synthesis Example 3>
A montmorillonite clay carrier treated with sulfuric acid (hereinafter abbreviated as Clay) (100 mg) as a carrier was washed with triethylaluminum, and dichlorobis (cyclopentadienyl) zirconium (hereinafter abbreviated as CZ) (0.003 mmol) as a metallocene complex. Then, it was brought into contact with a toluene solution of triethylaluminum (0.006 mmol) to obtain a toluene slurry of catalyst C (concentration: 0.1 g / mL).

<Synthesis Example 4>
Except having used BCH (0.003 mmol) as a metallocene complex, it implemented similarly to the synthesis example 3, and the toluene slurry of the catalyst D was obtained.

<Synthesis Example 5>
A catalyst E was obtained in the same manner as in Synthesis Example 2 except that RMAO (10 mmol) manufactured by Akzo was used as MAO.

<Synthesis Example 6>
Non-patent literature Organometallics 2007, 26, 5339. [N- (2,6-diisopropylphenyl) -2- (2,6-diisopropylphenylimino) propaneamidato-κ2N, O (η1-benzyl)] nickel (2,6-lutidine), (Hereinafter referred to as BL complex) was synthesized. This BL complex (10 mmol) was stirred in an acid-treated montmorillonite clay carrier (5 g) and a toluene solution for 10 minutes to obtain a toluene slurry of catalyst F.

<Synthesis Example 7>
Non-patent literature Am. Chem. Soc. 2001, 123, 5352. [N- (2,6-diisopropylphenyl) -2- (2,6-diisopropylphenylimino) propaneamidato-κ2N, O (η1-benzyl)] nickel (trimethylphosphine), (hereinafter referred to as BP complex) Was synthesized. This complex (1 mmol) was reacted with an equal amount of nickel bis (1,5-cyclopentadiene) in toluene to obtain a toluene slurry of catalyst G.

<Synthesis Example 8>
Catalyst H was prepared in the same manner as in Synthesis Example 1 except that silica gel having an average particle diameter of 11 microns was used.

The structures of the catalysts A to H produced in Synthesis Examples 1 to 8 are summarized in Table 1 below.

In addition, about the symbol used in Table 1, the following meaning is represented.
BCH: Dichlorobis (n-butylcyclopentadienyl) hafnium BCZ: Dichlorobis (n-butylcyclopentadienyl) zirconium CZ: Dichlorobis (cyclopentadienyl) zirconium BL: [N- (2,6-diisopropylphenyl)- 2- (2,6-Diisopropylphenylimino) propaneamidato-κ2N, O (η1-benzyl)] nickel (2,6-lutidine)
BP: [N- (2,6-diisopropylphenyl) -2- (2,6-diisopropylphenylimino) propaneamidato-κ2N, O (η1-benzyl)] nickel (trimethylphosphine)
SiO ₂ : Silica support Clay: Montmorillonite support MAO: Methylaluminoxane The expression “BCH / MAO” indicates that the catalyst is a catalyst in which BCH and MAO are co-supported.

<Example 1>
An autoclave with an induction stirring blade having an internal volume of 2 L was charged with n-hexane (1000 mL) as a solvent and triethylaluminum (0.5 mmol) as a scavenger. Next, catalyst A (150 mg) was charged into a catalyst feeder attached to the autoclave. After replacing the gas phase part of the autoclave with ethylene three times, heating was started, and when the temperature reached 80 ° C., the catalyst A was supplied into the autoclave, and then ethylene was supplied up to 2.5 MPa. The time when the internal pressure reached a predetermined pressure (2.5 MPa) was set as the polymerization start time, polymerization was performed for 60 minutes under a constant temperature and pressure condition, and then the unreacted monomer was purged to stop the polymerization. The polyethylene slurry was recovered, n-hexane was filtered off, and the resulting polymer powder was dried to obtain 298 g of polymer 1 which is an ethylene homopolymer.
The physical properties of this polymer 1 were measured, and the results are shown in Table 2.
Moreover, the obtained polymer 1 was used, the press piece was created based on the said test piece preparation method, and the abrasion test was done. The results are shown in Table 2.

<Example 2>
Instead of catalyst A, the catalyst B (150 mg) was used, the polymerization temperature was changed to 45 ° C., and the ethylene polymerization was carried out in the same manner as in Example 1 except that the ethylene pressure was changed to 3.0 MPa. As a result, 222 g of the polymer 2 was obtained. The evaluation results of Polymer 2 are shown in Table 2.

<Example 3>
Polymerization of ethylene was carried out in the same manner as in Example 1 except that the catalyst C (150 mg) was used in place of the catalyst A and the polymerization time was 90 minutes, to obtain 309 g of a polymer 3 which was an ethylene homopolymer. The evaluation results of the polymer 3 are shown in Table 2.

<Example 4>
Except that catalyst D (150 mg) was used instead of catalyst A, the organoaluminum added to the reactor was changed to triisobutylaluminum (0.5 mmol), and the polymerization time was 90 minutes, ethylene was the same as in Example 1. Then, 363 g of polymer 4 which is an ethylene homopolymer was obtained. The evaluation results of the polymer 4 are shown in Table 3.

<Example 5>
Ethylene was polymerized in the same manner as in Example 4 except that the polymerization temperature was 60 ° C., to obtain 403 g of polymer 5 which was an ethylene homopolymer. The evaluation results of the polymer 5 are shown in Table 3.

<Comparative Example 6>
Except that the polymerization temperature was 95 ° C. and the ethylene pressure was 1.2 MPa, ethylene was polymerized in the same manner as in Example 4 to obtain 257 g of polymer 6 which was an ethylene homopolymer. The evaluation results of the polymer 6 are shown in Table 3.

<Comparative Example 7>
An autoclave with an induction stirring blade having an internal volume of 2 L was charged with n-hexane (1000 mL) as a solvent, 70 mL of 1-hexene as a comonomer, and triethylaluminum (0.5 mmol) as a scavenger. Next, catalyst D (100 mg) was charged into a catalyst feeder attached to the autoclave. After replacing the gas phase part of the autoclave with ethylene three times, heating was started. When the temperature reached 65 ° C., the catalyst D was supplied into the autoclave, and then ethylene was supplied up to 2.5 MPa. The time when the internal pressure reached a predetermined pressure (2.5 MPa) was set as the polymerization start time, polymerization was performed for 60 minutes under a constant temperature and pressure condition, and then the unreacted monomer was purged to stop the polymerization. The polymer slurry was collected, n-hexane was filtered off, and the resulting polymer powder was dried to obtain 296 g of polymer 7 which is an ethylene / 1-hexene copolymer. The evaluation results of the polymer 7 are shown in Table 3.

<Comparative Example 8>
An autoclave with an induction stirring blade having an internal volume of 2 L was charged with n-hexane (1000 mL) as a solvent, 220 mL of 1-hexene as a comonomer, and triethylaluminum (0.2 mmol) as a scavenger. Next, ethylene containing hydrogen was supplied to the autoclave, and then catalyst E (100 mg) was charged into a catalyst feeder attached to the autoclave. After replacing the gas phase part of the autoclave with ethylene three times, heating was started, and when the temperature reached 40 ° C., the catalyst E was supplied into the autoclave and subsequently ethylene containing hydrogen was supplied up to 2.5 MPa. . The time when the internal pressure reached a predetermined pressure (2.5 MPa) is set as the polymerization start time, the average hydrogen concentration in the gas phase part of the reactor is maintained at 70 ppm, and after performing polymerization for 60 minutes under a constant temperature and pressure condition, Unreacted monomer was purged to stop the polymerization. The polymer slurry was recovered, n-hexane was filtered off, and the resulting polymer powder was dried to obtain 296 g of polymer 8 which is an ethylene / 1-hexene copolymer. The evaluation results of the polymer 8 are shown in Table 3.

<Comparative Example 9>
In the same manner as in Comparative Example 8, except that catalyst B (100 mg) was used in place of catalyst E, the polymerization temperature was 50 ° C., and the average hydrogen concentration in the gas phase of the reactor was maintained at 120 ppm, ethylene and 1-hexene Polymerization was performed to obtain 120 g of polymer 9 which was an ethylene / 1-hexene copolymer. The evaluation results of the polymer 9 are shown in Table 3.

<Comparative Example 10>
The amount of 1-hexene used was 30 mL, the polymerization temperature was 55 ° C., the ethylene pressure was 1.4 MPa, and the average hydrogen concentration in the reactor gas phase was 170 ppm. -Hexene copolymerization was carried out to obtain 215 g of polymer 10 which was an ethylene / 1-hexene copolymer. The evaluation results of the polymer 10 are shown in Table 3.

<Comparative Example 11>
Polymerization of ethylene in the same manner as in Example 1 except that catalyst F (0.5 g) was used instead of catalyst A, triethylaluminum was not used during the polymerization, the polymerization temperature was 43 ° C., and the ethylene pressure was 2.0 MPa. And 154 g of polymer 11 which is an ethylene homopolymer was obtained. The evaluation results of the polymer 11 are shown in Table 3.

<Comparative Example 12>
Example 1 except that catalyst G (450 mg) was used instead of catalyst A, triethylaluminum was not used during the polymerization, the polymerization temperature was 25 ° C., the ethylene pressure was 0.7 MPa, and the polymerization time was 50 minutes. Similarly, ethylene was polymerized to obtain 127 g of polymer 12 which is an ethylene homopolymer. The evaluation results of the polymer 12 are shown in Table 3.

<Example 6>
An autoclave with an induction stirring blade having an internal volume of 24 L was charged with n-hexane (10 L) as a solvent and triethylaluminum (5 mmol) as a scavenger. Next, catalyst H (330 mg) was charged into a catalyst feeder attached to the autoclave. After replacing the gas phase part of the autoclave with ethylene three times, heating was started, and when the temperature reached 85 ° C., the catalyst H was supplied into the autoclave, and then ethylene was supplied up to 2.0 MPa. The time when the internal pressure reached a predetermined pressure (2.0 MPa) was set as the polymerization start time, and after performing the polymerization for 180 minutes under the constant temperature and pressure conditions, the unreacted monomer was purged to terminate the polymerization. The polyethylene slurry was recovered, n-hexane was filtered off, and the resulting polymer powder was dried to obtain 1250 g of polymer 13 which was an ethylene homopolymer. The evaluation results of the polymer 13 are shown in Table 3.

<Example 7>
Polymerization of ethylene was carried out in the same manner as in Example 6 except that the catalyst H (1 g) was used, the polymerization temperature was 80 ° C., and the reaction time was 240 minutes, to obtain 4000 g of polymer 14 as an ethylene homopolymer. . The evaluation results of the polymer 14 are shown in Table 3.

<Comparative Example 1>
Ultra-high molecular weight polyethylene (Gicon 4150 Mw = 7.7 million manufactured by Ticona) was evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Comparative example 2>
Ultra-high molecular weight polyethylene (Gicon 4120 Mw = 5 million manufactured by Ticona) was evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Comparative Example 3>
A wear test was conducted in the same manner as in Example 1 using polyethylene (Lupolen 5261Z manufactured by Basell) manufactured using a commercially available Ziegler-Natta catalyst. In addition, the physical property value etc. of this polyethylene are described in the product database of Basell. The results are shown in Table 2.

<Comparative Example 4>
A commercially available polyethylene (HY320 manufactured by Nippon Polyethylene Co., Ltd.) was evaluated in the same manner as in Example 1. The results are shown in Table 2.

<Comparative Example 5>
Evaluation was performed in the same manner as in Example 1 for commercially available polyethylene (LM776031 manufactured by Equistar). The results are shown in Table 2.

In addition, about the symbol used in Table 2, Table 3, and Table 4 of the postscript, the following meaning is represented.
Mw: weight average molecular weight Mn: number average molecular weight Tm: melting point MFR: melt flow rate HLMFR: flow ratio melt flow rate SWA: sand / rubber wheel wear performance Sand Slurry: sand slurry wear performance

<Example 8>
Each powder of polymer 1 (300 g) and polymer 2 (700 g) was dry blended with a Henschel mixer. About the obtained polymer composition, while evaluating physical properties, the press piece was created based on the said test piece preparation method, and the abrasion test was done. The evaluation results are shown in Table 4.

<Example 9>
Each powder of polymer 1 (550 g) and polymer 2 (450 g) was dry blended with a Henschel mixer. About the obtained polymer composition, while evaluating physical properties, the press piece was created based on the said test piece preparation method, and the abrasion test was done. The evaluation results are shown in Table 4.

<Example 10>
Each powder of polymer 1 (550 g) and polymer 3 (450 g) was dry blended with a Henschel mixer. About the obtained polymer composition, while evaluating physical properties, the press piece was created based on the said test piece preparation method, and the abrasion test was done. The evaluation results are shown in Table 4.

<Example 11>
Each powder of polymer 1 (300 g) and polymer 12 (700 g) was dry blended with a Henschel mixer. About the obtained polymer composition, while evaluating physical properties, the press piece was created based on the said test piece preparation method, and the abrasion test was done. The evaluation results are shown in Table 4.

<Example 12>
Each powder of polymer 1 (550 g) and polymer 6 (450 g) was dry blended with a Henschel mixer. About the obtained polymer composition, while evaluating physical properties, the press piece was created based on the said test piece preparation method, and the abrasion test was done. The evaluation results are shown in Table 4.

<Example 13>
Each powder of polymer 2 (550 g) and polymer 5 (450 g) was dry blended with a Henschel mixer. About the obtained polymer composition, while evaluating physical properties, the press piece was created based on the said test piece preparation method, and the abrasion test was done. The evaluation results are shown in Table 4.

[Discussion]
From the results of the above examples and comparative examples, the following conclusions can be obtained.

(1) Melt fluidity In Comparative Examples 1 and 2, Mw exceeds 1 million. For this reason, even if it heats more than melting | fusing point, melt viscosity is too high and resin does not flow. Since the resin does not flow, MFR and HLMFR cannot be measured. On the other hand, in Examples 1 to 7, since Mw is less than 1 million, the resin flows when heated to the melting point or higher, and MFR and HLMFR can be measured.

(2) Wear test method and sand / rubber wheel wear performance When the ultra-high molecular weight polyethylene (Comparative Examples 1 and 2) commercially used for wear resistance is evaluated by the sand slurry wear test, the wear amount is 0 for each. .17Cm ^3, showed 0.19 cm ³ (see Table 2, Comparative examples 1 and 2).
On the other hand, even with ordinary polyethylene having a Mw of about 150,000 to 500,000 that cannot be used commercially for wear resistance, the amount of wear by the sand slurry wear test is about 0.29 to 0.59 cm ^3, which is extremely high. Good values comparable to molecular weight polyethylene are shown (Comparative Examples 3 to 5).
This result shows that the sand slurry wear test is not an appropriate evaluation method for relatively low molecular weight polyethylene, which is not ultra-high molecular weight.
In contrast, the sand / rubber wheel wear test clearly shows the wear resistance performance of the material over a wide molecular weight range. For example, when the wear amount of the ultrahigh molecular weight polyethylene used in Comparative Examples 1 and 2 is determined by a sand / rubber wheel abrasion test, both are about 0.04 (cm ³ ) (Comparative Examples 1 and 2). Similarly, in the case of low molecular weight polyethylene having Mw = 150,000 to 500,000, it is about 0.25 to 1.7 (cm ³ ) (Comparative Examples 3 to 5), and the difference between ultra high molecular weight polyethylene and low molecular weight polyethylene is It is clear. Further, as will be described later, when the molecular weight Mw of polyethylene is changed by determining the type of catalyst, the wear amount by the sand / rubber wheel wear test and the molecular weight Mw show a good correlation, and when the Mw is increased, the wear amount decreases. . This correlation is consistent with the relationship between wear resistance and molecular weight that has been conventionally considered. Again, the sand / rubber wheel wear test is not just a wear resistance assessment for ultra high molecular weight polyethylene, but is also an appropriate method for assessing the wear resistance of materials over a wide molecular weight range including low molecular weight polyethylene. It is shown that. As a result, the subsequent evaluation of wear resistance was performed mainly using the evaluation by the “sand / rubber wheel friction test”.

(3) Evaluation of the Invention In Examples 1 to 7, the ethylene-based polymer is produced by a single site catalyst, and the Mw is controlled in the range of 300,000 to less than 1 million. For this reason, a test piece obtained by molding a resin composition formed by adding an additive to the polymer exhibits good wear resistance of less than 0.13 cm ³ as sand / rubber wheel wear performance.
Examples 1 to 7 show that a metallocene catalyst alone or a blend of ethylene polymers using a plurality of metallocene catalysts may be used as the single site catalyst. It can also be seen that a silica carrier or a montmorillonite carrier may be used as the carrier. Furthermore, it turns out that an ethylene-type polymer may be formed using a nonmetallocene catalyst.
From Examples 8 to 10 and 13, it can be seen that even if a blend of a plurality of ethylene polymers is used, it is sufficient that the Mw is controlled within the range of 300,000 to less than 1,000,000. In addition, when blending a plurality of ethylene polymers from Examples 11 and 12, even if the Mw of each ethylene polymer resin is not controlled within the range of 300,000 to less than 1,000,000, It can be seen that the composition only needs to satisfy the conditions.

Although the present invention has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention. This application is based on a Japanese patent application filed on March 26, 2012 (Japanese Patent Application No. 2012-069395), the contents of which are incorporated herein by reference.

The wear-resistant resin molded body of the present invention can be applied to application fields where ultrahigh molecular weight polyethylene has been used, and the molded body can be manufactured with high productivity by a melt molding method. Is extremely useful. In addition, the wear-resistant resin molded article of the present invention has a relatively high crystallinity and can be used in fields and environments where heat resistance is required, and is extremely useful industrially.

Claims

An ethylene polymer for producing a wear-resistant resin molded article that satisfies the following (1) to (5).
(1) An ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms (2) Polymerized using a single site catalyst (3) Weight average molecular weight Mw (4) Melting point Tm is 130 ° C. or higher and lower than 135 ° C. (5) Sand / rubber wheel produced from a press piece obtained by press molding the ethylene-based polymer The sand / rubber wheel wear performance measured for the test specimen for wear test is 0.035 cm 3 or more and 0.24 cm 3 or less.
An ethylene resin composition for producing an abrasion-resistant resin molded article, which contains an ethylene polymer satisfying the following (1) to (4) and satisfies the following (6).
(1) An ethylene homopolymer or a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms (2) Polymerized using a single site catalyst (3) Weight average molecular weight Mw (4) Melting point Tm is 130 ° C. or higher and lower than 135 ° C. (6) Sand / rubber made from a press piece obtained by press-molding the ethylene-based resin composition Sand / rubber wheel wear performance measured on a test piece for wheel wear test is 0.035 cm 3 or more and 0.24 cm 3 or less.
The method for producing a wear-resistant resin molded product having a sand / rubber wheel wear performance of 0.035 cm 3 or more and 0.24 cm 3 or less, wherein the ethylene-based heavy for producing the wear-resistant resin molded product according to claim 1 is used. A method for producing a wear-resistant resin molded article, wherein the coalescence or the ethylene resin composition for producing a wear-resistant resin molded article according to claim 2 is molded in a melt-flowable state.
A wear-resistant resin molded article obtained by the method for producing a wear-resistant resin molded article according to claim 3.
A wear-resistant resin member comprising the wear-resistant resin molded product according to claim 4.
The wear-resistant resin member is a gear, cam, slider, lever, arm, clutch, pulley, roller, roller, key stem, key top, shutter, reel, washer, piston, cylinder, guide rail, ball bearing, nut, bolt The wear-resistant resin member according to claim 5, which is a mechanical component represented by a screw, a shaft, a bearing, and the like.
The wear-resistant resin member according to claim 5, wherein the wear-resistant resin member is a coating material represented by a lining material, a steel pipe coating material, a coating material, a ski sole, a snowboard sole, and the like.
6. The wear-resistant resin member is a member for an artificial graft tissue represented by an artificial hip joint, an artificial shoulder joint, an artificial spine, an artificial knee joint, an artificial elbow joint, an artificial ankle joint, an artificial finger joint, and the like. The wear-resistant resin member according to 1.
The wear-resistant resin member is a member for a liquid or gas conduction path represented by tubes, hoses, pipes, valves, joints, seals, gaskets, O-rings, columns, tanks, containers, bags, bottles, etc. The wear-resistant resin member according to claim 5.
The wear-resistant resin member according to claim 5, wherein the wear-resistant resin member is an intermediate processed product for a wear-resistant resin member represented by a sheet, a plate, a rod, a block, a round bar, and the like.