Molded body

Abstract

To provide a polyethylene-based molded article that suppresses metal leaching without containing fluororesin, and exhibits excellent sliding properties and wear resistance. [Solution] A molded article containing an ultra-high molecular weight polyethylene composition with low metal leaching.

Description

[Technical Field]

[0001] The present invention relates to a molded article, and more particularly to a molded article formed from a polyethylene-based material. [Background technology]

[0002] Molded articles formed from polyethylene-based materials, for example when used as containers for pharmaceuticals, may require low metal leaching and a good surface condition. As a technology to meet such demands, for example, Patent Document 1 discloses a polyethylene resin composition containing 99.90 to 99.99% by weight of polyethylene resin with a metal content of 20 ppm or less, and 0.01 to 0.10 parts by weight of vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene copolymer, as well as a high-purity chemical container made from this polyethylene resin composition.

[0003] On the other hand, organofluorine compounds such as fluororesins have been used in various industries due to their high heat resistance, chemical resistance, and other properties resulting from CF bonds. However, because they are persistent in the environment, bioaccumulative, and potentially harmful to human health, alternatives are needed. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-195436 [Overview of the project] [Problems that the invention aims to solve]

[0005] The present invention aims to provide a polyethylene-based molded article that does not contain fluororesin, has suppressed metal elution, and exhibits excellent sliding properties and wear resistance. [Means for solving the problem]

[0006] The present invention relates, for example, to the following [1] to [7]. [1] The daily metal elution rate determined according to the following steps (1) to (4) is 200 ppb / cm³. 2 A molded article comprising the following ultra-high molecular weight polyethylene composition. Procedure (1): Prepare a test specimen measuring 50 mm × 20 mm × 10 mm from the ultra-high molecular weight polyethylene composition. Procedure (2): The test specimen is immersed in 102 g of 3.6 mass% hydrochloric acid at 23°C for 1 hour, then removed from the hydrochloric acid, and then immersed in 102 g of separately prepared 3.6 mass% hydrochloric acid at 23°C for 24 hours to obtain eluate a. Procedure (3): Take 10 g from eluate a and measure the mass reference concentration A (ppb) of each metal element Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ag, Cd, Sn, and Pb in eluate a by ICP mass spectrometry. Procedure (4): The daily elution amount of each metal element is calculated using the following formula (ppb / cm³). 2 Calculate ). Daily elution amount = above concentration A (ppb) / 34 (cm 2 ) Next, the daily leaching amounts of each metal element are totaled to obtain the daily metal leaching amount (ppb / cm³). 2 Calculate ).

[0007] [2] The 1-week metal elution amount of the aforementioned ultra-high molecular weight polyethylene composition, determined according to the following steps (5) to (7), is 500 ppb / cm³. 2 The molded body of [1] described above is as follows: Procedure (5): Add 10 g of 3.6% by mass hydrochloric acid to the remaining eluate a after 10 g has been collected in procedure (4), and immerse the test piece at 23°C for 144 hours to obtain eluate b. Procedure (6): The mass reference concentration B (ppb) of each metal element Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ag, Cd, Sn, and Pb in the eluate b is measured by ICP mass spectrometry. Procedure (7): The one-week elution amount (ppb / cm 2 ) of each of the above metal elements is calculated according to the following formula. One-week elution amount = the above concentration B (ppb) / 34 (cm 2 ) Next, the one-week elution amounts of each of the above metal elements are summed to calculate the one-week metal elution amount (ppb / cm 2 ).

[0008] [3] The molded body of the above [1] or [2], wherein the ultra-high molecular weight polyethylene composition contains a conductive filler.

[0009] [4] The molded body of the above [3], wherein the conductive filler is a carbon nanotube. [5] The molded body of any one of the above [1] to [4], wherein the ultra-high molecular weight polyethylene composition does not contain a fluororesin.

[0010] [6] The molded body of any one of the above [1] to [5], which is an injection molded body. [7] The molded body of any one of the above [1] to [6], which is a sliding material.

Advantages of the Invention

[0011] The molded body of the present invention has a suppressed metal elution amount without containing a fluororesin, and is excellent in slidability and wear resistance.

Modes for Carrying Out the Invention

[0012] Hereinafter, the present invention will be described in more detail. The molded body of the present invention contains an ultra-high molecular weight polyethylene composition having a small amount of metal impurities.

[0013] [Ultra-high molecular weight polyethylene composition] <Metal elution amount> The amount of metal impurities in the ultra-high molecular weight polyethylene composition is small, and the amount of metal eluted from the composition by immersing the ultra-high molecular weight polyethylene composition in dilute hydrochloric acid is within a specific range.

[0014] Specifically, the amount of metal eluted from the ultra-high molecular weight polyethylene composition by immersion in dilute hydrochloric acid for one day, that is, the one-day metal elution amount determined according to the following procedures (1) to (4), is 200 ppb / cm 2 Hereinafter, preferably 120 ppb / cm 2 Hereinafter, more preferably 100 ppb / cm 2 Hereinafter, even more preferably 50 ppb / cm 2 is within the following range. The lower limit value may be, for example, 0 ppb / cm 2 and may be. Procedure (1): Prepare a test piece with a size of 50 mm × 20 mm × 10 mm made of the ultra-high molecular weight polyethylene composition. Procedure (2): Immerse the test piece in 102 g of 3.6 mass% hydrochloric acid at 23°C for 1 hour, then take it out of the hydrochloric acid, and then immerse it in 102 g of separately prepared 3.6 mass% hydrochloric acid at 23°C for 24 hours to obtain an eluate a. Procedure (3): Collect 10 g from the eluate a, and measure the mass-based concentration A (ppb) of each metal element of Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ag, Cd, Sn, and Pb in the eluate a by ICP mass spectrometry. Procedure (4): Calculate the one-day elution amount (ppb / cm 2 ) of each metal element according to the following formula. One-day elution amount = the concentration A (ppb) / the surface area of the test piece (that is, 34 (cm 2 )) Then, sum up the one-day elution amounts of each metal element to calculate the one-day metal elution amount (ppb / cm 2 ).

[0015] Furthermore, the amount of metal leached from the ultra-high molecular weight polyethylene composition by immersion in dilute hydrochloric acid for one week, i.e., the amount of metal leached over one week determined according to the following steps (5) to (7), is preferably 500 ppb / cm³. 2 More preferably, 200 ppb / cm² 2 More preferably, 160 ppb / cm² 2 The following is particularly preferred: 120 ppb / cm² 2 The range is as follows. The lower limit is, for example, 5 ppb / cm². 2 That's fine. Procedure (5): Add 10 g of 3.6% by mass hydrochloric acid to the remaining eluate a after 10 g has been collected in procedure (4), and immerse the test piece at 23°C for 144 hours to obtain eluate b. Procedure (6): The mass reference concentration B (ppb) of each metal element Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ag, Cd, Sn, and Pb in the eluate b is measured by ICP mass spectrometry. Procedure (7): The weekly elution amount of each metal element (ppb / cm³) is calculated using the following formula. 2 Calculate ). Weekly elution amount = Concentration B (ppb) / Surface area of ​​the test specimen (i.e., 34 cm²) 2 )) Next, the weekly leaching amounts of each metal element are totaled to obtain the weekly metal leaching amount (ppb / cm³). 2 Calculate ).

[0016] <Ultra-high molecular weight polyethylene> The ultra-high molecular weight polyethylene composition contains ultra-high molecular weight polyethylene. In this invention, for convenience, not only mixtures of ultra-high molecular weight polyethylene and other components, but also ultra-high molecular weight polyethylene alone may be referred to as an "ultra-high molecular weight polyethylene composition."

[0017] Ultra-high molecular weight polyethylene is polyethylene with a particularly large molecular weight compared to general polyethylene (for example, high-density polyethylene or low-density polyethylene with a weight-average molecular weight of 20,000 to 300,000).

[0018] Ultra-high molecular weight polyethylene is, for example, a homopolymer of ethylene or a copolymer of ethylene and α-olefins. Examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, and 3-methyl-1-pentene, which are α-olefins having 3 to 20 carbon atoms. The above copolymers are copolymers that have ethylene-derived structural units as their main component. The main component refers to the structural unit that has the highest content ratio (mol%) among the structural units contained in the copolymer.

[0019] Ultra-high molecular weight polyethylene may have only constituent units derived from fossil fuel-derived raw material monomers, or only constituent units derived from biomass-derived raw material monomers, or it may have both constituent units derived from fossil fuel-derived raw material monomers and constituent units derived from biomass-derived raw material monomers. Examples of the above raw material monomers include ethylene and α-olefins.

[0020] Biomass-derived raw material monomers are raw material monomers made from any (renewable) natural raw materials and their residues, including fungi, yeasts, algae, and bacteria, which are of plant or animal origin. Examples of biomass-derived raw material monomers include carbon... 14 1.0 × 10¹¹ C isotopes -14 ~1.0×10 -12 Examples of raw material monomers include those containing a certain proportion and having a biomass carbon concentration (unit: pMC) of approximately 100 pMC, as measured in accordance with ASTM D6866. Biomass-derived raw material monomers can be obtained, for example, by conventionally known methods.

[0021] Ultra-high molecular weight polyethylene having constituent units derived from biomass-derived raw material monomers is preferable from the viewpoint of reducing environmental impact (mainly reducing greenhouse gases). If the manufacturing conditions such as polymerization catalyst, polymerization process, and polymerization temperature are equivalent, polyethylene having constituent units derived from biomass-derived raw materials, 14 1.0 × 10¹¹ C isotopes -14 ~1.0×10 -12 Aside from the proportion of other components present, the molecular structure and physical properties are equivalent to those of polyethylene containing only constituent units derived from fossil fuel-derived raw material monomers. Therefore, the performance of polyethylene containing constituent units derived from biomass-derived raw material monomers is considered to be equivalent to that of polyethylene containing only constituent units derived from fossil fuel-derived raw material monomers.

[0022] Ultra-high molecular weight polyethylene can be produced, for example, by polymerizing monomers containing at least ethylene in the presence of a known olefin polymerization catalyst. The ultra-high molecular weight polyethylene composition may contain one type of ultra-high molecular weight polyethylene, or it may contain two or more types of ultra-high molecular weight polyethylene.

[0023] <Conductive filler> The ultra-high molecular weight polyethylene composition may contain a conductive filler. When the ultra-high molecular weight polyethylene composition contains a conductive filler, for example, a molded article with high conductivity can be formed.

[0024] Examples of conductive fillers include conductive carbon. Examples of conductive carbon include carbon nanotubes, carbon powder, carbon fibers, and fullerenes, and among these, carbon nanotubes are preferred from the viewpoint of being able to effectively reduce the surface resistivity and volume resistivity of the molded article.

[0025] The average diameter of carbon nanotubes may be, for example, 0.5 to 300 nm or 1 to 200 nm. The average fiber length of carbon nanotubes may be, for example, 0.01 to 100 μm or 1 to 10 μm. The average diameter of carbon nanotubes is determined by observing the carbon nanotubes with a scanning electron microscope (SEM) and taking the arithmetic mean of the individual diameters. The average fiber length of carbon nanotubes is determined by observing the carbon nanotubes with an SEM and taking the arithmetic mean of the individual fiber lengths.

[0026] The secondary particle shape of carbon nanotubes is not particularly limited. For example, it may be a complex arrangement of carbon nanotubes of a common shape, or it may be an aggregate of easily unraveled, linearly shaped carbon nanotubes.

[0027] The carbon nanotubes may be surface-treated. The carbon nanotubes may have functional groups, such as carboxyl groups. The carbon nanotubes may be multi-walled or single-walled.

[0028] Carbon nanotubes can be produced, for example, by laser ablation, arc discharge, thermochemical vapor deposition (CVD), plasma CVD, or combustion. Commercially available carbon nanotubes may also be used.

[0029] Examples of carbon powder include carbon black. Examples of carbon black include furnace black, acetylene black, and Ketjen black. Carbon black can be produced by decomposition methods such as the thermal black method and the acetylene black method, and by incomplete combustion methods such as the channel black method, gas furnace black method, oil furnace black method, pine soot method, and lamp black method.

[0030] The ultra-high molecular weight polyethylene composition may contain one conductive filler, or it may contain two or more conductive fillers. The content of the conductive filler in the ultra-high molecular weight polyethylene composition is preferably 1 to 30 parts by mass, more preferably 5 to 25 parts by mass, and even more preferably 7 to 15 parts by mass, per 100 parts by mass of ultra-high molecular weight polyethylene. Such an ultra-high molecular weight polyethylene composition can, for example, form a molded article that has high conductivity and excellent sliding properties and wear resistance.

[0031] The total content of ultra-high molecular weight polyethylene and conductive filler in the ultra-high molecular weight polyethylene composition is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 1.4% or 70% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, 95% by mass or more, 98% by mass or more, or 99% by mass or more, based on 100% by mass of the ultra-high molecular weight polyethylene composition.

[0032] <Other ingredients> The ultra-high molecular weight polyethylene composition may further contain thermoplastic resins other than ultra-high molecular weight polyethylene, such as polyolefins.

[0033] The ultra-high molecular weight polyethylene composition may contain additives. Examples of additives include heat stabilizers, antioxidants, ultraviolet absorbers, weathering agents, colorants (dyes, pigments, etc.), antistatic agents, fillers other than conductive fillers, flame retardants, flame retardant enhancers, anti-fogging agents, lubricants, anti-blocking agents, flow improvers, plasticizers, dispersants, antibacterial agents, mold release agents, foaming agents, tackifiers, sealant improvers, crosslinking agents, coupling agents, and surfactants. The ultra-high molecular weight polyethylene composition may contain one additive or two or more additives.

[0034] <Fluororesin> On the other hand, the ultra-high molecular weight polyethylene composition preferably does not contain fluororesin, i.e., fluorine-containing resin. By using a polyethylene-based material that does not contain fluorine-containing resin and contains ultra-high molecular weight polyethylene as polyethylene (i.e., the ultra-high molecular weight polyethylene composition) instead of a polyethylene-based material containing fluorine-containing resin, it is possible to manufacture molded articles with excellent abrasion resistance and reduced environmental impact.

[0035] <Preparation of ultra-high molecular weight polyethylene composition> The ultra-high molecular weight polyethylene composition can be prepared, for example, by mixing ultra-high molecular weight polyethylene with other components (e.g., carbon nanotubes) by, for example, melt kneading. Alternatively, the ultra-high molecular weight polyethylene composition can be prepared, for example, by dry blending ultra-high molecular weight polyethylene with other components (e.g., carbon nanotubes) and then melt kneading. Examples of melt kneading methods include using a single-screw extruder, a multi-screw extruder, or a tandem extruder.

[0036] Commercially available products may be used as the ultra-high molecular weight polyethylene composition. Examples of commercially available products include Lubmer® L3000, L4000, and L5000 manufactured by Mitsui Chemicals, Inc.

[0037] [Molded body] The molded article of the present invention comprises the ultra-high molecular weight polyethylene composition. The molded article can be manufactured, for example, by conventionally known methods for molding polyolefins, except that an ultra-high molecular weight polyethylene composition is used as the molding material. Examples of methods for molding polyolefins include injection molding, injection compression molding, extrusion molding, press molding, calendering, foam molding, pipe molding, inflation molding, and injection blow molding. The molded article of the present invention is preferably obtained by molding an ultra-high molecular weight polyethylene composition by injection molding. That is, the molded article of the present invention is preferably an injection-molded article.

[0038] The molded article of the present invention may be a molded article formed from the above-mentioned ultra-high molecular weight polyethylene composition. The molded article of the present invention may also be a molded article having a portion formed from the ultra-high molecular weight polyethylene composition, for example, a surface layer.

[0039] [Applications of molded products] Examples of molded articles of the present invention include household goods, general industrial goods, and industrial products. Examples of such molded articles include communication equipment parts, electrical components, electronic components, semiconductor equipment parts, flat panel display manufacturing equipment parts, semiconductor transport containers, automobile parts, other vehicle parts, home appliance material parts, ship parts, aircraft parts, mechanical mechanism parts, building material parts, civil engineering materials, agricultural materials, power tool parts, food containers, films, sheets, and fibers.

[0040] The molded articles of the present invention have excellent sliding properties and wear resistance, making them suitable for use as sliding materials. Furthermore, when the molded articles of the present invention contain carbon fibers, they have excellent conductivity, making them suitable for use in applications requiring antistatic properties, for example.

[0041] Examples of the sliding materials include oil-less bearings, joints, bearings, gears, silling pistons, rollers, valves, tubes, packings, chuck pins; metal coatings (laminated) such as steel pipes, electric wires, and automobile sliding door rails; various rubber coatings (laminated) such as pressure-resistant rubber hoses, automobile door gaskets, cleanroom door gaskets, automobile glass run channels, and automobile weatherstrips; and various protective liner materials for lining hoppers, chutes, etc. [Examples]

[0042] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0043] [Raw materials] The raw materials used in each example are as follows: L5000 Lubmer L5000, manufactured by Mitsui Chemicals, Inc. Ultra-high molecular weight polyethylene composition LF4820 Lubmer LF4820, manufactured by Mitsui Chemicals, Inc. Ultra-high molecular weight polyethylene composition LF4840 Lubmer LF4840, manufactured by Mitsui Chemicals, Inc. Ultra-high molecular weight polyethylene composition · LK4920 Lubmer LK4920, manufactured by Mitsui Chemicals, Inc. Conductive filler-containing ultra-high molecular weight polyethylene composition

[0044] [Example 1] Ultra-high molecular weight polyethylene composition (L5000) was melted at 270°C using an injection molding machine EC75SX-III manufactured by Shibaura Machine Co., Ltd., and molded at an injection pressure of 100 MPa and a holding pressure of 40 MPa to produce molded articles in the form of rectangular parallelepipeds measuring 120 mm × 130 mm × 3 mm thick and rectangular parallelepipeds measuring 50 mm × 20 mm × 10 mm thick.

[0045] [Examples 2-4] A molded article was prepared in the same manner as in Example 1, except that the ultra-high molecular weight polyethylene composition (L5000) was changed to the ultra-high molecular weight polyethylene composition listed in Table 1.

[0046] [Evaluation Method] [Quantitative determination of metal elution] <Pre-washing> The 50mm x 20mm x 10mm thick (surface area 34cm²) fabricated in each example 2 The molded body was pre-cleaned. Specifically, the molded body, as a test specimen, was immersed in 102 g (100 mL) of 3.6% by mass hydrochloric acid (commercially available ultra-high purity hydrochloric acid diluted with ultrapure water) in a clean container at room temperature (23°C) for 1 hour.

[0047] <Immersion test (measurement of metal leaching amount over 1 day)> After pre-washing, the test specimens removed from the hydrochloric acid were immersed in 102 g (100 mL) of 3.6% by mass hydrochloric acid (commercially available ultra-high purity hydrochloric acid diluted with ultrapure water) in a clean container at room temperature (23°C) for 24 hours to obtain eluate a.

[0048] Ten g of the obtained eluate a (i.e., hydrochloric acid after immersion of the test specimen for 24 hours) was taken, and quantitative analysis of Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ag, Cd, Sn, and Pb was performed by ICP mass spectrometry using an Agilent 8900 ICP-MS / MS measuring instrument. Based on the measured mass reference concentration of each metal element (mass of each metal element / mass of eluate a) (ppb), the daily elution amount of each metal element was determined using the following formula. Daily elution amount (ppb / cm 2 ) = Concentration A (ppb) / Surface area of ​​the test specimen (i.e., 34 cm²) 2 ) Next, the daily leaching amounts of each metal element are totaled to obtain the daily metal leaching amount (ppb / cm³). 2 The result was calculated. The results are shown in Table 1.

[0049] <Immersion test (measurement of metal leaching amount over 1 week)> In the immersion test (measurement of metal leaching amount per day), 10 g was taken and 10 g of 3.6 mass% hydrochloric acid was added to the remaining eluate a. The test specimen was then immersed at room temperature (23°C) for a further 144 hours (6 days) to obtain eluate b.

[0050] Ten g was taken from the obtained eluate b (i.e., hydrochloric acid after immersing the test specimens for a total of 168 hours), and quantitative analysis of Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ag, Cd, Sn, and Pb was performed by ICP mass spectrometry under the following conditions. The mass reference concentration B (mass of each metal element / mass of eluate b) (ppb) of each measured metal element was calculated, and the amount of metal eluted over one week was determined from the following formula. Weekly elution (ppb / cm³) 2 ) = Concentration B (ppb) / Surface area of ​​the test specimen (i.e., 34 cm²)2 ) Next, the weekly leaching amounts of each metal element are totaled to obtain the weekly metal leaching amount (ppb / cm³). 2 The result was calculated. The results are shown in Table 1.

[0051] [Sliding properties (coefficient of dynamic friction) and wear resistance (specific wear rate)] A 120mm x 130mm x 3mmt molded body was punched out from each example to create a 30mm x 30mm x 3mmt test specimen. Using this test specimen, the dynamic friction coefficient and specific wear amount were measured using a Matsubara friction wear tester in accordance with JIS K7218 "Sliding wear test method A for plastics". The results are shown in Table 1.

[0052] The test conditions are as follows: Countering material: Carbon steel (S45C) Speed: 50cm / sec, Distance: 3km Load: 15kgf Measurement environment temperature: 23℃

[0053] [Table 1]

Claims

1. The daily metal elution rate determined according to the following steps (1) to (4) is 200 ppb / cm³. 2 A molded article comprising the following ultra-high molecular weight polyethylene composition. Procedure (1): Prepare a test specimen measuring 50 mm × 20 mm × 10 mm from the ultra-high molecular weight polyethylene composition. Procedure (2): The test specimen is immersed in 102 g of 3.6 mass% hydrochloric acid at 23°C for 1 hour, then removed from the hydrochloric acid, and then immersed in 102 g of separately prepared 3.6 mass% hydrochloric acid at 23°C for 24 hours to obtain eluate a. Procedure (3): Take 10 g from eluate a and measure the mass reference concentration A (ppb) of each metal element Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ag, Cd, Sn, and Pb in eluate a by ICP mass spectrometry. Procedure (4): The daily elution rate of each metal element (ppb / cm³) is calculated using the following formula. 2 Calculate the result. Daily dissolution amount = Previous concentration A (ppb) / 34 (cm³) 2 ) Next, the daily elution amounts of each metal element are totaled to obtain the daily metal elution amount (ppb / cm³). 2 Calculate the result.

2. The weekly metal elution rate of the ultra-high molecular weight polyethylene composition, determined according to the following steps (5) to (7), is 500 ppb / cm³. 2 The molded article according to claim 1, which is as follows: Procedure (5): Add 10 g of 3.6% by mass hydrochloric acid to the eluate a remaining after 10 g was taken in procedure (4), and immerse the test piece at 23°C for 144 hours to obtain eluate b. Procedure (6): The mass reference concentration B (ppb) of each metal element Li, Na, Mg, Al, K, Ca, Ti, Cr, Mn, Fe, Ni, Cu, Zn, Mo, Ag, Cd, Sn, and Pb in the eluate b is measured by ICP mass spectrometry. Procedure (7): The weekly elution amount of each metal element (ppb / cm³) is calculated using the following formula. 2 Calculate the result. Weekly elution amount = Concentration B (ppb) / 34 (cm³) 2 ) Next, the weekly leaching amounts of each metal element are totaled to obtain the weekly metal leaching amount (ppb / cm²). 2 Calculate the result.

3. The molded article according to claim 1, wherein the ultra-high molecular weight polyethylene composition comprises a conductive filler.

4. The molded article according to claim 3, wherein the conductive filler is a carbon nanotube.

5. The molded article according to claim 1, wherein the ultra-high molecular weight polyethylene composition does not contain fluororesin.

6. The molded article according to any one of claims 1 to 5, which is an injection-molded article.

7. A molded article according to any one of claims 1 to 5, which is a sliding material.

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