Guide rail

Abstract

To provide a guide rail which has a smooth surface, has excellent wear resistance, has excellent dimensional accuracy as well and can be utilized in a wide range to guide various bodies to be conveyed while sliding in contact therewith.SOLUTION: Provided is a guide rail in which at least a part of a sliding contact part is composed of an ethylene polymer composition including an ethylene polymer (A) and a carbon filler (B). The guide rail guides bodies to be conveyed which are conveyed by conveyance means, and at least a part of the sliding contact face of the guide rail in slide-contact with the bodies to be conveyed is composed of the ethylene polymer composition including the ethylene polymer (A) and the carbon filler (B).SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a guide rail, and more particularly to a guide rail made of ultra-high molecular weight polyethylene, which has excellent wear resistance and dimensional accuracy. [Background technology]

[0002] Guide rails that guide the moving object in the direction of travel are susceptible to wear at the sliding surface with the object, and are therefore required to be made from a material with excellent wear resistance. For example, guide rails that guide objects to be conveyed, such as products conveyed by conveying means such as a belt conveyor, are often made of polyethylene resin or the like with excellent wear resistance at the sliding surface with which the object to be conveyed slides. It has also been proposed to make them from a material with excellent wear resistance, such as ultra-high molecular weight polyethylene (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-289610 A Summary of the Invention [Problem to be solved by the invention]

[0004] Guide rails are required to have a smooth surface, excellent wear resistance, and excellent dimensional accuracy. Polyethylene resin and ultra-high molecular weight polyethylene have excellent smoothness and wear resistance, but the dimensional accuracy of guide rails molded from them may not be sufficient depending on the application of the guide rail.

[0005] In view of these problems, it has been found that by forming at least a part of the sliding contact portion of a guide rail from an ethylene-based polymer composition containing an ethylene-based polymer (A) and a carbon-based filler (B), a guide rail having excellent smoothness, wear resistance and dimensional accuracy can be obtained, and thus the present invention has been completed. [Means for solving the problem]

[0006] The outline of the present invention is as follows. (1) A guide rail, at least a part of a sliding contact portion of the guide rail being made of an ethylene-based polymer composition containing an ethylene-based polymer (A) and a carbon-based filler (B). (2) A guide rail for guiding an object to be transported by a transport means, A guide rail, at least a part of a sliding contact surface of the guide rail with which a transported object slides is made of an ethylene-based polymer composition containing an ethylene-based polymer (A) and a carbon-based filler (B). (3) Ethylene-based polymer composition The content of the ethylene polymer (A) is 70 to 99.9% by mass, The content of the carbon-based filler (B) is 0.1 to 30 mass%. (wherein the total amount of the ethylene-based polymer (A) and the carbon-based filler (B) is 100 mass %). (4) The guide rail according to any one of (1) to (3), wherein the carbon-based filler (B) is a carbon nanotube. (5) The ethylene polymer (A) is The intrinsic viscosity [η] measured in decalin solvent at 135°C is 1.5 to 10 dl / g, and the density is 930 to 980 kg / m 3 The guide rail according to any one of (1) to (4), (6) The ethylene polymer (A) is 10 to 90% by mass of an ethylene polymer component (AI) and 90 to 10% by mass of an ethylene polymer component (AII) (wherein the total amount of the ethylene-based polymer component (AI) and the ethylene-based polymer component (AII) is taken as 100 mass %). The guide rail according to any one of (1) to (5). (7) The ethylene polymer component (AI) is an ultra-high molecular weight ethylene polymer (a1) having an intrinsic viscosity [η] of 10 to 40 dl / g measured in a decalin solvent at 135° C., which is more than 35% by mass and not more than 90% by mass; A low-molecular-weight or high-molecular-weight ethylene polymer (a2) having an intrinsic viscosity [η] of 0.1 to 9 dl / g measured in decalin solvent at 135° C. is contained in an amount of 10% by mass or more and less than 65% by mass. (wherein the total amount of the ultra-high molecular weight ethylene polymer (a1) and the low- to high-molecular weight ethylene polymer (a2) is 100 mass %), The ethylene polymer component (AII) is The guide rail according to (6), comprising an ethylene polymer (a3) ​​having an intrinsic viscosity [η] of 0.1 to 2.9 dl / g as measured in decalin solvent at 135°C. (8) The ethylene polymer composition further contains 30% by mass or less of a polyamide. (wherein the total amount of the ethylene-based polymer (A), the carbon-based filler (B) and the polyamide is taken as 100 mass %). A guide rail according to any one of (1) to (7). (9) The guide rail according to any one of (1) to (8), which is obtained by injection molding. Effect of the Invention

[0007] The guide rail of the present invention uses a composition containing an ethylene-based polymer (A) and a carbon-based filler (B) in at least a part of its sliding contact portion, and has excellent smoothness, wear resistance, and dimensional accuracy. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Examples of situations in which guide rails are used include the following: When a large number of machine parts slide down an inclined plane as a group, guide rails are provided to squeeze the multiple machine parts together from both sides in order to control the number of parts and regulate the direction in which they slide down. When various products are placed on a belt conveyor and transported, guide rails are provided on both sides of the belt conveyor to keep the products on the conveyor belt and prevent the products from falling off the conveyor belt. When various products are placed on the spiral conveyor and transported, the spiral conveyor itself on which the products are placed runs in sliding contact with guide rails. In this manner, the object being conveyed comes into sliding contact with the sliding contact portion of the guide rail, and wears out due to friction caused by long-term use.

[0009] In addition, guide rails made of ultra-high molecular weight polyethylene with a weight-average molecular weight Mw of more than 1 million have excellent abrasion resistance, but may not be easy to thermoform. For this reason, molded guide rails have excellent smoothness and abrasion resistance, but are prone to sink marks and warping, and guide rails with excellent dimensional accuracy are required. The present invention is characterized in that at least a part of the sliding contact portion of the guide rail is made of an ethylene-based polymer composition containing an ethylene-based polymer (A) and a carbon-based filler (B).

[0010] <Ethylene-based polymer (A)> The ethylene-based polymer (A) used in the present invention is a homopolymer of ethylene or a copolymer of ethylene and an α-olefin, and is a polymer mainly composed of ethylene, generally called high-pressure low-density polyethylene (HP-LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), or ultra-high molecular weight polyethylene. Here, a polymer mainly composed of ethylene means a polymer in which the content ratio (mol %) of structural units derived from ethylene is the highest among all structural units contained in the polymer, and is usually a polymer in which the content ratio of structural units derived from ethylene is 50 mol % or more.

[0011] When the ethylene polymer (A) used in the present invention is a copolymer, it may be a random copolymer or a block copolymer. The α-olefin copolymerized with ethylene is preferably an α-olefin having 3 to 20 carbon atoms, specifically, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-nonadecene, 1-eicosene, 9-methyl-1-decene, 11-methyl-1-dodecene, and 12-ethyl-1-tetradecene, etc. These α-olefins are used alone or in combination of two or more kinds.

[0012] The ethylene polymer (A) may be a single polymer or a composition (mixture) of two or more kinds of ethylene polymers. The ethylene polymer (A) may be a polymer in which a part of the ethylene polymer (A) is modified with a polar compound, or may contain an ethylene polymer modified with a polar compound.

[0013] As a method for modifying the ethylene polymer (A), various known methods can be adopted. For example, a method can be mentioned in which the ethylene polymer (A) is dissolved in an organic solvent, and then a polar compound such as an unsaturated carboxylic acid or its derivative and a radical initiator such as an organic peroxide are added to the obtained solution, and the solution is reacted for 0.5 to 15 hours, preferably 1 to 10 hours, at a temperature of usually 60 to 350 ° C, preferably 80 to 190 ° C. Alternatively, a method can be mentioned in which the ethylene polymer (A), an unsaturated carboxylic acid or its derivative and a radical initiator such as an organic peroxide are added without a solvent, using an extruder or the like, and the mixture is reacted for 0.5 to 10 minutes at a temperature above the melting point of the ethylene polymer (A), preferably 160 to 350 ° C.

[0014] When the ethylene polymer (A) contains a modified ethylene polymer, the amount thereof is usually in the range of 0.5 to 6 mass%, and preferably in the range of 0.5 to 4 mass% based on the total ethylene polymer composition described below.

[0015] When the ethylene-based polymer composition contains a modified ethylene-based polymer, the wettability between the ethylene-based polymer (A) and the carbon-based filler (B) is improved, and the tensile strength at break, flexural strength, flexural modulus, dynamic friction coefficient, and specific wear rate are further improved.

[0016] The ethylene polymer (A) is preferably an ultra-high molecular weight polyethylene having an intrinsic viscosity [η] measured in decalin solvent at 135° C. (hereinafter, sometimes simply referred to as “intrinsic viscosity [η]”) of 10 to 40 dl / g.

[0017] When the above-mentioned ultra-high molecular weight polyethylene is used as the ethylene polymer (A), it is also preferable to prepare a composition of two or more kinds of ethylene polymers containing a low-molecular-weight to high-molecular-weight ethylene polymer having an intrinsic viscosity [η] of 0.1 to 9 dl / g, which is one of the preferred embodiments of the present invention.

[0018] Further, in one preferred embodiment of the present invention, the ethylene polymer (A) is a composition (mixture) containing two or more of the following ethylene polymers. That is, the ethylene polymer (A) is 10 to 90% by mass of an ethylene-based polymer component (AI) and 90 to 10% by mass of an ethylene-based polymer component (AII) (The total amount of the ethylene polymer component (AI) and the ethylene polymer component (AII) is 100 mass %). The ethylene polymer component (AI) is The composition comprises an ultra-high molecular weight ethylene polymer (component (a1)) having an intrinsic viscosity [η] of 10 to 40 dl / g and a low- to high-molecular weight ethylene polymer (component (a2)) having an intrinsic viscosity [η] of 0.1 to 9 dl / g, Based on the total mass of components (a1) and (a2), component (a1) is more than 35 mass% and 90 mass% or less, and component (a2) is 10 mass% or more and less than 65 mass%, Furthermore, the density of the ethylene polymer component (AI) is 930 to 980 kg / m 3 and the intrinsic viscosity [η] is 3.0 to 10.0 dl / g; In a preferred embodiment of the present invention, the other ethylene polymer component (AII) contains at least an ethylene (co)polymer having an intrinsic viscosity [η] of 0.1 to 2.9 dl / g.

[0019] Furthermore, the ethylene polymer component (AII) has a density of 820 to 980 kg / m 3 and more preferably, the intrinsic viscosity [η] is 0.1 to 2.9 dl / g.

[0020] The blending ratio of the ethylene-based polymer component (AI) to the ethylene-based polymer component (AII) is preferably 15 to 90 mass% of the ethylene-based polymer component (AI) and 85 to 10 mass% of the ethylene-based polymer component (AII), more preferably 20 to 80 mass% of the ethylene-based polymer component (AI) and 80 to 20 mass% of the ethylene-based polymer component (AII), and even more preferably 26.7 to 49 mass% of the ethylene-based polymer component (AI) and 73.3 to 51 mass% of the ethylene-based polymer component (AII).

[0021] <Ethylene-based polymer component (AI)> When the present invention is one of the above-mentioned preferred embodiments, the ultra-high molecular weight ethylene polymer (component (a1)) constituting the ethylene polymer component (AI) has an intrinsic viscosity [η] measured in decalin solvent at 135° C. within the range of preferably 10 to 40 dl / g, more preferably 15 to 35 dl / g, and even more preferably 20 to 35 dl / g, and such a component can be obtained, for example, by the first-stage polymerization.

[0022] On the other hand, the low-molecular-weight to high-molecular-weight ethylene polymer (component (a2)), which is the other component constituting the ethylene polymer component (AI), has an intrinsic viscosity [η] measured in a decalin solvent at 135° C. in the range of preferably 0.1 to 9 dl / g, more preferably 0.1 to 5 dl / g, even more preferably 0.5 to 3 dl / g, and even more preferably 1.0 to 2.5 dl / g. Such a component can be obtained, for example, by a second-stage polymerization after polymerization of an ultra-high molecular weight ethylene polymer. The ethylene polymer component (AI) containing the components (a1) and (a2) can be produced by polymerizing ethylene and, if desired, an α-olefin in multiple stages in the presence of a catalyst. The method of polymerization in multiple stages can be performed in the same manner as the polymerization method described in JP-A-2-289636.

[0023] By using an ultra-high molecular weight ethylene polymer (component (a1)) having an intrinsic viscosity [η] within the above range, a guide rail having excellent abrasion resistance, self-lubrication, impact strength, chemical resistance, etc. can be obtained.

[0024] In addition, the ethylene polymer component (AI) obtained by post-polymerizing a low-molecular-weight to high-molecular-weight ethylene polymer (component (a2)) having an intrinsic viscosity [η] within the above range together with such an ultra-high molecular weight ethylene polymer (component (a1)) has improved compatibility with the ethylene polymer component (AII). As a result, the ultra-high molecular weight ethylene polymer is uniformly dispersed and bonded, and an ethylene polymer composition having an excellent balance of properties such as abrasion resistance, self-lubrication, impact strength, chemical resistance, appearance and moldability, and particularly an excellent balance of abrasion resistance, appearance and moldability, can be obtained.

[0025] In addition, by using a low- or high-molecular-weight ethylene polymer (component (a2)) having an intrinsic viscosity [η] within the above range in combination with an ultrahigh molecular weight ethylene polymer (component (a1)) having an intrinsic viscosity [η] within the above range, the carbon-based filler (B) becomes more easily dispersed.

[0026] When the present invention is one of the above-mentioned preferred embodiments of the present invention, the ethylene polymer composition preferably contains an ultra-high molecular weight ethylene polymer (component (a1)) in an amount of more than 35 mass % and not more than 90 mass % and a low- to high-molecular weight ethylene polymer (component (a2)) in an amount of 10 mass % or more and less than 65 mass %.

[0027] By setting the ratio of the ultra-high molecular weight ethylene polymer (component (a1)) to the low to high molecular weight ethylene polymer (component (a2)) within the above range, an ultra-high molecular weight ethylene polymer having a larger particle shape can be obtained. Also, the compatibility with the ethylene polymer component (AII) is improved, and an ethylene polymer composition having excellent abrasion resistance, appearance and moldability can be obtained.

[0028] The ethylene polymer component (AI) contains the component (a1) in an amount more preferably greater than 40 mass% and not greater than 80 mass%, and even more preferably from 41 to 75 mass%, and contains the component (a2) in an amount more preferably from 20 mass% to less than 60 mass%, and even more preferably from 25 to 59 mass%.

[0029] The sum of the content of the ultra-high molecular weight ethylene polymer (component (a1)) and the content of the low- to high molecular weight ethylene polymer (component (a2)) in the ethylene polymer component (AI) is usually 100 mass %, but in addition to these, so long as the object of the present invention is not impaired, additives that are usually added to polyolefins (for example, stabilizers such as heat stabilizers and weather stabilizers, crosslinking agents, crosslinking assistants, antistatic agents, slip agents, antiblocking agents, antifogging agents, lubricants, dyes, pigments, fillers, mineral oil-based softeners, petroleum resins, waxes, compatibilizers, etc.) may be contained.

[0030] The ethylene polymer component (AI) containing the component (a1) and the component (a2), which are substantially composed of an ultra-high molecular weight ethylene polymer and a low to high molecular weight ethylene polymer, preferably has a density of 930 to 980 kg / m as measured in accordance with ASTM D1505. 3 , more preferably 940 to 980 kg / m 3The range is.

[0031] By having a density within the above range, the dynamic friction coefficient of the guide rail is reduced, and therefore a guide rail with excellent self-lubricating properties can be obtained.

[0032] The ethylene polymer component (AI) has an intrinsic viscosity [η] measured in decalin solvent at 135° C. in the range of preferably 3.0 to 10.0 dl / g, more preferably 3.0 to 8.0 dl / g, and further preferably 3.0 to 7.0 dl / g.

[0033] By having the intrinsic viscosity [η] within the above range, the ethylene polymer component (AI) and the ethylene polymer component (AII) are well dispersed.

[0034] That is, the low-molecular-weight to high-molecular-weight ethylene polymer contained in the ethylene polymer component (AI) and the ethylene polymer component (AII) melt-blended in an extruder or the like are finely dispersed in each other, resulting in a uniform dispersion state. Therefore, by using the above ethylene polymer composition, a guide rail excellent in abrasion resistance, self-lubrication, impact strength, chemical resistance, appearance, moldability, etc. can be obtained.

[0035] The ethylene polymer component (AI) can be blended with other polymers to improve wear resistance, self-lubrication, etc., and is preferably used as a resin modifier. There is no limitation on the polymer to be modified, but the ethylene polymer component (AII) is preferred.

[0036] <Ethylene-based polymer component (AII)> The ethylene polymer component (AII) is not particularly limited as long as it is a composition containing at least an ethylene polymer having an intrinsic viscosity [η] of 0.1 to 2.9 dl / g. Examples of the ethylene polymer include high-pressure low-density polyethylene (HP-LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), high-density polyethylene (HDPE), ethylene-α-olefin copolymer, ethylene-vinyl alcohol copolymer, ethylene-vinyl acetate copolymer, saponified ethylene-vinyl acetate copolymer, ethylene-(meth)acrylic acid copolymer, and ethylene-α-olefin-diene (triene, polyene) terpolymer. Examples of the α-olefin include those having 3 to 20 carbon atoms, such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 3-methyl-1-pentene. Examples of the diene (triene, polyene) include 5-ethylidene-2-norbornene, vinylnorbornene, and conjugated or non-conjugated dienes, trienes, and polyenes.

[0037] The ethylene polymer component (AII) may be the above-mentioned ethylene polymer alone or a composition of two or more ethylene polymers, or a composition of an ethylene polymer with another polyolefin such as polypropylene or polybutene.

[0038] The density of the ethylene polymer component (AII) is 820 to 980 kg / m 3 , preferably 850 to 970 kg / m 3 , more preferably 860 to 960 kg / m 3 and the intrinsic viscosity [η] is 0.1 to 2.9 dl / g, preferably 0.3 to 2.8 dl / g, and more preferably 0.5 to 2.5 dl / g.

[0039] Preferred polymers contained in the ethylene polymer component (AII) are those having a density of 820 to 980 kg / m 3Examples of the polymers include ethylene polymers having an intrinsic viscosity [η] of 0.1 to 2.9 dl / g, compositions of polypropylene and ethylene-α-olefin-diene copolymers, and ethylene-vinyl alcohol copolymers.

[0040] Since the ethylene polymer component (AII) is a composition containing at least an ethylene polymer having an intrinsic viscosity [η] of 0.1 to 2.9 dl / g, the dispersion state with the ethylene polymer component (AI) is improved. That is, during melt blending in an extruder, the ethylene polymer component (AII) and the low-molecular-weight or high-molecular-weight ethylene polymer contained in the ethylene polymer component (AI) are finely dispersed with each other, resulting in a uniform dispersion state. Therefore, by using this composition, a guide rail excellent in wear resistance, self-lubrication, impact strength, chemical resistance, appearance, flexibility, moldability, etc. can be obtained.

[0041] The ethylene polymer component (AII) may contain additives that are typically added to polyolefins (for example, stabilizers such as heat stabilizers and weather stabilizers, crosslinking agents, crosslinking assistants, antistatic agents, slip agents, antiblocking agents, antifogging agents, lubricants, dyes, pigments, fillers, mineral oil-based softeners, petroleum resins, waxes, compatibilizers, etc.) within the range that does not impair the object of the present invention.

[0042] <Carbon-based filler (B)> Examples of the carbon-based filler (B) include carbon nanotubes (CNT), conductive carbon black (CB), and carbon fibers. The carbon-based filler (B) is not particularly limited as long as it is a material having electrical conductivity, but among these, carbon nanotubes are preferred because they have an excellent effect of reducing the surface electrical resistivity of the guide rail.

[0043] Carbon nanotubes are cylindrical hollow fibrous substances made of carbon, and may be either multi-walled or single-walled carbon nanotubes. The average diameter of the carbon nanotubes is preferably 1 nm or more, more preferably 5 nm or more, even more preferably 7 nm or more, and preferably 20 nm or less. The average length of the carbon nanotubes is preferably 0.5 μm or more, more preferably 0.6 μm or more, and preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 15 μm or less. If the average diameter is 1 nm or more, it is possible to make the nanotubes less likely to break during kneading, and if it is 20 nm or less, it is likely to increase the electrical conductivity. If the average length is 0.5 μm or more, it is possible to increase the electrical conductivity, and if it is 50 μm or less, it is likely to suppress the increase in viscosity during kneading, and to facilitate kneading and molding.

[0044] The average diameter and average length of the carbon nanotubes can be determined by observing the carbon nanotubes under an electron microscope (SEM, TEM) and calculating the arithmetic average. Carbon nanotubes can be produced by, for example, an arc discharge method, a chemical vapor deposition method (CVD method), or a laser ablation method. Commercially available carbon nanotubes may also be used.

[0045] Carbon nanotubes tend to exhibit high electrical conductivity in a relatively small amount compared to, for example, carbon black, but are expensive, so it is advantageous from the viewpoint of cost if they can be used in a smaller amount. In this embodiment, since excellent electrical conductivity can be obtained by using an ethylene polymer composition containing a specific ethylene polymer (A), high electrical conductivity tends to be obtained even with a small amount of carbon nanotubes.

[0046] Examples of conductive carbon black include furnace black, ketjen black, channel black, lamp black, thermal black, and acetylene black. Specific examples include HAF-LS, HAF, HAF-HS, FEF, GPF, APF, SRF-LM, SRF-HM, and MT.

[0047] The primary particle diameter of the conductive carbon black is preferably 0.005 μm or more, more preferably 0.01 μm or more, and is preferably 1 μm or less, more preferably 0.2 μm or less. The primary particle diameter is the average particle diameter measured with an electron microscope or the like.

[0048] As the carbon fiber, various known carbon fibers can be used, for example, polyacrylonitrile-based, rayon-based, pitch-based, polyvinyl alcohol-based, regenerated cellulose-based, pitch-based produced from mesophase pitch, etc. Carbon fibers are advantageous in applications where light weight and strength are important, such as for aircraft, because of their excellent specific strength.

[0049] The carbon fibers may be general-purpose fibers or high-strength fibers, and may be long fibers, short fibers, chopped fibers, or recycled fibers. As a sizing agent for carbon fibers, for example, any of urethane-based emulsions, epoxy-based emulsions, nylon-based emulsions, and olefin-based emulsions can be used.

[0050] The average length of the carbon fibers, i.e., the average fiber length, is preferably 0.1 mm or more, more preferably 0.3 mm or more, even more preferably 0.5 mm or more, and is preferably 15.0 mm or less, more preferably 13.0 mm or less. When the average fiber length is 0.1 mm or more, the reinforcing effect of the mechanical properties due to the carbon fibers tends to be fully exhibited. When the average fiber length is 15.0 mm or less, the dispersibility of the carbon fibers in the ethylene polymer composition is excellent, and thus the appearance tends to be good.

[0051] The average diameter of the carbon fibers is preferably 3 μm or more, more preferably 5 μm or more, and preferably 30 μm or less, more preferably 21 μm or less, and even more preferably 19 μm or less. When the average diameter of the carbon fibers is 3 μm or more, the carbon fibers are less likely to break during molding, and the impact strength of the resulting guide rail tends to be high. When the average diameter of the carbon fibers is 30 μm or less, the appearance of the guide rail tends to be good, and the aspect ratio of the carbon fibers does not decrease, and sufficient reinforcing effect tends to be obtained in the mechanical properties such as the rigidity and heat resistance of the guide rail.

[0052] The carbon-based filler (B) can be used alone or in combination. <Ethylene-Based Polymer Composition> The ethylene-based polymer composition used in the present invention is a composition containing the above ethylene-based polymer (A) and the above carbon-based filler (B). The content of the above ethylene-based polymer (A) is preferably 70 to 99.9 mass%, more preferably 85.0 to 99.9 mass%, and the content of the above carbon-based filler (B) is preferably in the range of 0.1 to 30 mass%, more preferably 0.1 to 15.0 mass%. (The total amount of the ethylene-based polymer (A) and the carbon-based filler (B) is 100 mass %).

[0053] The ethylene polymer composition usually has an MFR measured in accordance with JIS K 7210-1:2014 at 230° C. under a load of 10 kg in the range of preferably 0.01 to 20 g / 10 min, more preferably 0.1 to 20 g / 10 min. The ethylene-based polymer composition may further contain a polyamide, if necessary, in addition to the carbon-based filler (B).

[0054] <Polyamide> Examples of polyamides that can be used in the present invention include polyamide 6, polyamide 66, polyamide 11, polyamide 12, polyamide 610, polyamide 612, polyamide 614, polyamide 6T, polyamide 6I, polyamide 9T, polyamide M5T, polyamide 1010, polyamide 1012, polyamide 10T, polyamide MXD6, polyamide 6T / 66, polyamide 6T / 6I, polyamide 6T / 6I / 66, polyamide 6T / 2M-5T, and polyamide 9T / 2M-8T.

[0055] The polyamide may be a block copolymer containing a polyamide component. Examples of the block copolymer containing a polyamide component include polyamide elastomers, which are block copolymers using polyether diols and polyester diols. Examples of the polyether diols include polytetramethylene ether glycol and polyoxypropylene glycol.

[0056] One or more kinds of polyamides can be used. When the ethylene polymer composition contains a polyamide, the carbon-based filler (B) is easily dispersed in the ethylene polymer (A), and the abrasion resistance and electrical conductivity are further improved.

[0057] When the ethylene polymer composition contains a polyamide, the amount thereof is preferably 30% by mass or less, more preferably 1.0 to 30% by mass, further preferably 5 to 30% by mass, and particularly preferably 5 to 20% by mass. (The total amount of the ethylene polymer (A), the carbon-based filler (B) and the polyamide is 100 mass %.)

[0058] The ethylene polymer composition may contain, as necessary, various additives usually used in polyolefins, such as heat stabilizers, weather stabilizers, ultraviolet absorbers, light stabilizers, talc, calcium carbonate, metal powder, titanium oxide, and zinc oxide (excluding the carbon-based filler (B)), wax, lubricants, slipping agents, nucleating agents, antiblocking agents, antistatic agents, antifogging agents, pigments, dyes, dispersants, flame retardants, flame retardant assistants, plasticizers, and compatibilizers, or other polymers, such as impact strength modifiers (elastomers), within the range that does not impair the object of the present invention.

[0059] When the ethylene polymer composition contains the above additives or polymers, the amount thereof is not particularly limited, but is usually in the range of 0.01 to 30% by mass. The ethylene-based polymer composition preferably contains a wax as another component. The type of wax is not particularly limited, but polyethylene-based wax and polypropylene-based wax are preferred.

[0060] It is considered that when the ethylene-based polymer composition contains a wax, the aggregation of the carbon-based filler (B) in the ethylene-based polymer (A) is suppressed, making kneading easier and dispersing the carbon-based filler in the ethylene-based polymer (A). Therefore, an ethylene-based polymer composition having high electrical conductivity is obtained. It is also considered that it becomes easier to knead a high content of the carbon-based filler (B) into the ethylene-based polymer (A). When the ethylene polymer composition contains a wax, the amount thereof is usually in the range of 0.01 to 10% by mass.

[0061] <Method of producing ethylene polymer composition> The ethylene polymer composition can be obtained by a conventionally known production method, for example, by dry blending an ethylene polymer (A), a carbon-based filler (B), and, if necessary, a polyamide or the above-mentioned various additives, followed by melt kneading in a single-screw or twin-screw extruder, extruding the mixture in a strand shape, and granulating the mixture into pellets. Note that components such as the carbon-based filler (B) and inorganic filler may be previously mixed with a polymer component such as the ethylene polymer (A) to form a master batch.

[0062] The monomers constituting the polymers such as the ethylene-based polymer composition and each of the ethylene-based polymers constituting the ethylene-based polymer composition (the ethylene-based polymer component (AI), the ethylene-based polymer component (AII), the ultra-high molecular weight ethylene-based polymer (a1), the low- to high-molecular weight ethylene-based polymer (a2), and the ethylene-based polymer (a3)) may at least partially contain a biomass-derived monomer (another monomer such as ethylene or an α-olefin). The same type of monomers constituting the polymer may be only biomass-derived monomers, may be only fossil fuel-derived monomers, or may contain both biomass-derived monomers and fossil fuel-derived monomers. The biomass-derived monomer is a monomer obtained by using any renewable natural raw material and its residue, such as a plant-derived or animal-derived material including fungi, yeast, algae, and bacteria, as a raw material, and contains carbon as the raw material. 14 C isotope 1×10 -12 The biomass carbon concentration (unit: pMC) measured in accordance with ASTM D6866 is about 100 pMC. The biomass-derived monomers (ethylene, α-olefins, and other monomers) can be obtained, for example, by a conventionally known method.

[0063] It is preferable from the viewpoint of reducing the environmental load (mainly reducing greenhouse gases) that the monomer constituting the polymer such as the ethylene-based polymer composition contains a structural unit derived from a biomass-derived monomer. If the polymer production conditions such as the polymerization catalyst, polymerization process, and polymerization temperature are the same, even if the raw material monomer is a (co)polymer containing a biomass-derived monomer, 14 C isotope 1×10 -12 ~10 -14 Other than the proportion of fossil fuel-derived monomers, the molecular structure is the same as that of (co)polymers made from fossil fuel-derived monomers. Therefore, the performance is said to be the same.

[0064] <Guide rail> The guide rail of the present invention is molded by a conventionally known polyolefin molding method, for example, a thermoforming method such as extrusion molding, injection molding, press molding, calendar molding, etc. Since the guide rail of the present invention can be injection molded, the injection molding method is preferred from the viewpoint of ease of molding. The guide rail of the present invention has excellent surface smoothness, wear resistance, and dimensional accuracy.

[0065] The present invention will now be described with reference to examples, but the present invention is not limited to these examples. <Example> [Raw materials] The raw materials used in the examples are as follows: (Ethylene-based polymer component (AI)) <Production of ethylene polymer component (AI)> By a conventional method, an ultra-high molecular weight ethylene polymer (polymer (a1)) having an intrinsic viscosity [η] of 30 dl / g was produced in a first polymerization stage, and then a low molecular weight ethylene polymer (polymer (a2)) having an intrinsic viscosity [η] of 1.5 dl / g was produced in a second polymerization stage in a mass ratio (polymer (a1) / polymer (a2)) of 41 / 59 to obtain an ethylene polymer component (AI-1) having an intrinsic viscosity [η] of 4.4 dl / g.

[0066] (Ethylene-based polymer component (AII)) The following ethylene polymer components were used: Ethylene-based polymer component (AII-1): Intrinsic viscosity [η] is 1.1 dl / g, density is 965 kg / m 3 High density, low molecular weight polyethylene (manufactured by Prime Polymer Co., Ltd., product name Hi-Zex 1700J)

[0067] (Ethylene-based polymer (A)) <Production of ethylene polymer (A)> The ethylene polymer component (AI-1) and the ethylene polymer component (AII-1) obtained above were mixed in a mass ratio ((AI) / (AII)) of 49 / 51, and melt blended using an Ikegai Iron Works PCM twin-screw extruder to obtain a pellet-shaped ethylene polymer (A-1) having an intrinsic viscosity [η] of 3.0 dl / g. The content of the ultra-high molecular weight ethylene polymer (polymer (a1)) in the ethylene polymer (A-1) was 20 mass %.

[0068] (Carbon-based filler (B)) The following carbon-based fillers were used: Carbon-based filler (B-1): Carbon nanotubes (average diameter: 9.5 nm, average length: 1.5 μm, Nanosil NC7000)

[0069] (Master batch (MB) containing carbon-based filler) 《Manufacturing master batches (MB) containing carbon-based fillers》 A carbon-based filler-containing master batch (MB-1) was produced by mixing 15 mass % of a carbon-based filler (B-1), 75 mass % of an ethylene-based polymer (A-1), and 10 mass % of a wax (polyethylene-based wax).

[0070] In the following examples, the ethylene-based polymer composition was prepared from the above-mentioned ethylene-based polymer (A-1) and the carbon-based filler-containing master batch (MB-1) and used.

[0071] Example 1 <Preparation of Ethylene-Based Polymer Composition> The ethylene polymer (A-1) was dry-blended at 60% by mass with the carbon-based filler-containing master batch (MB-1) at 40% by mass, and then the mixture was charged into the hopper of a BT30 twin-screw extruder manufactured by Plastics Engineering Research Institute Co., Ltd., and melt-kneaded at 230° C. to obtain a pellet-shaped ethylene polymer composition. The proportions of each component are shown in Table 1. The physical properties of the ethylene polymer composition were measured by the methods described below, and the results are shown in Table 1.

[0072] <Manufacturing guide rail components> The ethylene polymer composition obtained above was placed in the hopper of a Toshiba 75-ton injection molding machine manufactured by Toshiba Machine Co., Ltd., melted at 230°C, and injection molded into a mold at 30°C under an injection pressure of 100 MPa and a holding pressure of 60 MPa to produce a guide rail member measuring 10 mm x 150 mm x 2 mm in thickness. The results obtained by the measurement method described below are shown in Table 1.

[0073] [Examples 2 to 5] An ethylene-based polymer composition was produced in the same manner as in Example 1, except that the ethylene-based polymer (A-1) and the carbon-based filler-containing master batch (MB-1) were prepared in the amounts shown in Table 1, and a guide rail member was produced by injection molding. Table 1 shows the physical properties of the ethylene polymer composition and the evaluation results of the guide rail member.

[0074] [Examples 6 and 7] An ethylene-based polymer composition was produced in the same manner as in Example 1, except that polyamide (polyamide 6, manufactured by Toray Industries, Inc., product name Amilan CM1007) was used, and the ethylene-based polymer (A-1), carbon-based filler-containing master batch (MB-1), and polyamide were prepared in the amounts shown in Table 1, and a guide rail member was produced by injection molding. The physical properties of the ethylene-based polymer composition and the evaluation results of the guide rail member are shown in Table 1.

[0075] Measurement method The methods for measuring and evaluating the physical properties of the compositions obtained in the examples are as follows. [Intrinsic viscosity [η] (unit: dl / g)] In accordance with ASTM D4020, the above ethylene polymer (A) was dissolved in decalin, and the intrinsic viscosity measured at 135° C. was taken as [η].

[0076] [Density (unit: kg / m 3 )〕 The density of the ethylene polymer (A) was measured by a density gradient method in accordance with ASTM D1505. The density of the ethylene polymer compositions obtained in the examples was measured in water at 23° C. by a liquid weighing method in accordance with JIS Z8807:2012.

[0077] [Appearance of guide rail component] The appearance of the obtained guide rail member was visually inspected and evaluated according to the following criteria. Yes: uneven molding marks are observed on the surface of the guide rail component. None: No uneven molding sink marks are observed on the surface of the guide rail component.

[0078] [Warpage of guide rail components (unit: mm)] The guide rail member obtained above, measuring 10 mm x 150 mm x 2 mm in thickness, was used. The 10 mm x 150 mm surface of the guide rail member was placed on a flat surface, and one end of the 10 mm long part was pressed against the flat surface. The height (unit: mm) by which the 10 mm long end on the opposite side to the pressed side rose above the flat surface was measured. If there is no floating, the value is 0 mm.

[0079] [Surface resistivity (unit: Ω / □)] [Volume resistivity (unit: Ω cm)] The above-obtained guide rail member having dimensions of 10 mm x 150 mm x 2 mm (thickness) was used. Using an ADC Corporation digital ultra-high resistance / microcurrent meter 8340A, the surface resistivity (unit: Ω / □) and volume resistivity (unit: Ω·cm) were measured by the double ring method under the following conditions: temperature: 23°C, humidity: 50%, applied voltage: 500V, and application time: 60 seconds. The surface resistivity in the above measurement is 1.0×10 7 In the following cases, measurements were performed in accordance with JIS K7194:1994 using a low resistance resistivity meter Loresta-GX-MCP-T700 manufactured by Nitto Seiko Analytech Co., Ltd., using a four-probe method under the conditions of applied current: 0.1 μA to 10 mA, application time: 10 seconds, temperature: 23° C., and humidity: 50%.

[0080] [Table 1] [Industrial Applicability]

[0081] The guide rail of the present invention has a smooth surface, excellent wear resistance, and excellent dimensional accuracy, and can be widely used as various guide rails that guide various transport objects while making sliding contact with them.

Claims

1. A guide rail, at least a part of a sliding contact portion of the guide rail being made of an ethylene-based polymer composition containing an ethylene-based polymer (A) and a carbon-based filler (B).

2. A guide rail for guiding an object to be transported by a transport means, A guide rail, at least a part of a sliding contact surface of the guide rail with which a transported object slides is made of an ethylene-based polymer composition containing an ethylene-based polymer (A) and a carbon-based filler (B).

3. Ethylene-based polymer composition The content of the ethylene polymer (A) is 70 to 99.9% by mass, The content of the carbon-based filler (B) is 0.1 to 30 mass%.

3. The guide rail according to claim 1 or 2, wherein the total amount of the ethylene-based polymer (A) and the carbon-based filler (B) is 100 mass %.

4. 3. The guide rail according to claim 1 or 2, wherein the carbon-based filler (B) is a carbon nanotube.

5. The ethylene polymer (A) is The intrinsic viscosity [η] measured in decalin solvent at 135° C. is 1.5 to 10 dl / g, and the density is 930 to 980 kg / m ３ The guide rail according to claim 1 or 2,

6. The ethylene polymer (A) is 10 to 90% by mass of the ethylene polymer component (AI) and 90 to 10% by mass of the ethylene polymer component (AII) 3. The guide rail according to claim 1 or 2, wherein the total amount of the ethylene-based polymer component (AI) and the ethylene-based polymer component (AII) is 100 mass %.

7. The ethylene polymer component (AI) is an ultra-high molecular weight ethylene polymer (a1) having an intrinsic viscosity [η] of 10 to 40 dl / g measured in decalin solvent at 135° C., and A low-molecular-weight to high-molecular-weight ethylene polymer (a2) having an intrinsic viscosity [η] of 0.1 to 9 dl / g measured in decalin solvent at 135° C. is contained in an amount of 10% by mass or more and less than 65% by mass. (wherein the total amount of the ultra-high molecular weight ethylene polymer (a1) and the low- to high-molecular weight ethylene polymer (a2) is 100 mass%.) The ethylene polymer component (AII) is The guide rail according to claim 6, comprising an ethylene polymer (a3) ​​having an intrinsic viscosity [η] of 0.1 to 2.9 dl / g measured in a decalin solvent at 135 ° C.

8. The ethylene polymer composition further contains 30% by mass or less of a polyamide. (The total amount of the ethylene polymer (A), the carbon-based filler (B), and the polyamide is 100 mass%.) The guide rail according to claim 1 or 2.

9. 3. A guide rail according to claim 1 or 2, obtained by injection molding.