Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L23/00—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers
  • C08L23/02—Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers not modified by chemical after-treatment
  • C08L23/04—Homopolymers or copolymers of ethene
  • C08L23/06—Polyethylene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
  • C08F110/00—Homopolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond
  • C08F110/02—Ethene
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
  • C08K3/00—Use of inorganic substances as compounding ingredients
  • C08K3/02—Elements
  • C08K3/04—Carbon
  • C08K3/041—Carbon nanotubes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2205/00—Polymer mixtures characterised by other features
  • C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
  • C08L2205/025—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
  • C08L2207/00—Properties characterising the ingredient of the composition
  • C08L2207/06—Properties of polyethylene
  • C08L2207/068—Ultra high molecular weight polyethylene

Definitions

• One embodiment of the present invention relates to an ethylene-based resin composition or a molded article using the composition.
• Ethylene polymers with extremely high molecular weights are superior to general-purpose ethylene polymers in impact resistance, abrasion resistance, chemical resistance, and strength, and have excellent characteristics as engineering plastics.
• Such ultra-high molecular weight ethylene polymers are known to be obtained using known catalysts such as so-called Ziegler catalysts consisting of halogen-containing transition metal compounds and organometallic compounds, and magnesium compound-supported catalysts.
• Patent Document 2 As a method for improving the sliding properties and mechanical properties of an ethylene-based polymer, dispersion of cellulose fibers in the ethylene-based polymer has been proposed (Patent Document 2).
• Patent Document 3 As a composition containing an ultra-high molecular weight ethylene polymer and with improved electrical conductivity, a composition containing an ethylene polymer and a carbon-based filler and having a melt flow rate (MFR, measured at 230° C. and under a load of 10 kg) in the range of 0.1 to 20 g/10 min has been proposed (Patent Document 3).
• MFR melt flow rate
• Patent Document 3 has excellent electrical conductivity and, furthermore, has the excellent feature of being moldable by injection molding despite containing an ultra-high molecular weight ethylene polymer, but depending on the application, there may be cases where improved abrasion resistance is required.
• One embodiment of the present invention provides a composition that is excellent in both electrical conductivity and injection moldability, as well as in abrasion resistance.
• a molded article comprising the ethylene-based resin composition (X) described in any one of [1] to [5].
• One embodiment of the present invention provides a composition that is excellent in both electrical conductivity and injection moldability, as well as in abrasion resistance.
• the ethylene-based resin composition (X) (hereinafter also referred to as “resin composition (X)”) contains 100 parts by mass of an ethylene-based polymer composition (A) and 1 to 30 parts by mass of a carbon-based filler (B).
• the ethylene polymer composition (A) preferably contains a specific ultra-high molecular weight ethylene polymer (a1) and a specific low- to high-molecular weight ethylene polymer (a2) (hereinafter also referred to as "ethylene polymer (a2)").
• the ultra-high molecular weight ethylene polymer (a1) preferably satisfies the following requirement (a1-a).
• the ultra-high molecular weight ethylene polymer (a1) has an intrinsic viscosity [ ⁇ ] measured in a decalin solvent at 135° C. of preferably 10 to 40 dl/g, more preferably 15 to 35 dl/g, and further preferably 20 to 40 dl/g. 35 dl/g. Details of the measurement conditions and the like are as described in the Examples section below.
• the wear resistance of the ethylene polymer composition (A) tends to be good.
• the wear resistance, self-lubrication, impact strength, and chemical resistance of the resin composition (X) containing the ethylene polymer composition (A) and the molded product obtained from the resin composition (X) tend to be good.
• the melt fluidity of the ethylene polymer composition (A) and the resin composition (X) containing the ultra-high molecular weight ethylene polymer (a1) tends to be high.
• the ethylene polymer composition (A) and the resin composition (X) containing the ultra-high molecular weight ethylene polymer (a1) can achieve both wear resistance and moldability.
• the ultra-high molecular weight ethylene polymer (a1) is a homopolymer of ethylene or a copolymer of ethylene and an ⁇ -olefin such as propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 4-methyl-1-pentene, or 3-methyl-1-pentene.
• the ultra-high molecular weight ethylene polymer (a1) is preferably a homopolymer of ethylene or a copolymer of ethylene and the above-mentioned ⁇ -olefin, a copolymer composed of ethylene as the main component, and more preferably a homopolymer of ethylene.
• the main component means the component with the highest content (mol %) among the structural units contained in the polymer.
• the ethylene polymer (a2) preferably satisfies one or more of the following requirements (a2-a) and (a2-b).
• the intrinsic viscosity [ ⁇ ] of the ethylene polymer (a2) measured in decalin solvent at 135° C. is preferably 0.1 to 9.0 dl/g, more preferably 0.1 to 5.0 dl/g. , more preferably 0.5 to 3.0 dl/g, and particularly preferably 1.0 to 2.5 dl/g. Details of the measurement conditions and the like are as described in the Examples section below.
• the intrinsic viscosity [ ⁇ ] of the ethylene-based polymer (a2) measured in a decalin solvent at 135°C is 0.1 dl/g or more
• the abrasion resistance of the ethylene-based polymer composition (A) tends to be good.
• the abrasion resistance of the resin composition (X) containing the ethylene-based polymer composition (A) and the molded article obtained from the resin composition (X) tends to be good.
• the melt fluidity of the ethylene-based polymer composition (A) and the resin composition (X) containing the ethylene-based polymer composition (A) tends to be high.
• the intrinsic viscosity [ ⁇ ] of the ethylene-based polymer (a2) measured in a decalin solvent at 135°C is 0.1 to 9.0 dl/g, it is easy to obtain an ethylene-based polymer composition (A) and a resin composition (X) having excellent abrasion resistance and moldability.
• the carbon-based filler (B) used to prepare the resin composition (X) is easily dispersed, and a sufficient amount of the carbon-based filler (B) can be contained to give the resin composition (X) the desired electrical conductivity.
• the density of the ethylene polymer (a2) is preferably 920 to 985 kg/m 3 , more preferably 940 to 985 kg/m 3 , further preferably 950 to 980 kg/m 3 , and more preferably 950. up to 975 kg/ m3 , and more preferably 960 to 975 kg/ m3 . Details of the measurement conditions and the like are as described in the Examples section below. When the density of the ethylene polymer (a2) is 920 kg/ m3 or more, the crystallinity of the ethylene polymer (a2) is high enough not to impair the slipperiness of the surface of the ethylene polymer (a2).
• the obtained ethylene-based polymer composition (A) and the resin composition (X) containing the ethylene-based polymer composition (A) tend to have excellent abrasion resistance. Since the density of polyethylene is usually 985 kg/m 3 or less, a polyethylene having a density of 985 kg/m 3 or less is used as the ethylene polymer (a2).
• the ethylene polymer (a2) is a homopolymer of ethylene or a copolymer of ethylene and an ⁇ -olefin, and preferably is a homopolymer of ethylene.
• the ⁇ -olefin constituting the copolymer includes linear or branched ⁇ -olefins having 3 to 20 carbon atoms, specifically propylene, 1-butene, 1-pentene, 3-methyl-1-butene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 3,4-dimethyl-1-pentene, 4-methyl-1-hexene, 3-ethyl-1-pentene, 3-ethyl-4-methyl-1-pentene, 3,4-dimethyl-1-hexene, 4-methyl-1-heptene, 3,4-dimethyl-1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene
• the copolymer of ethylene and ⁇ -olefin preferably contains 90 mol% or more of structural units derived from ethylene, and more preferably contains 95 mol% or more of structural units derived from ethylene.
• the copolymer of ethylene and ⁇ -olefin preferably contains 10 mol% or less of structural units derived from ⁇ -olefin, and more preferably contains 5 mol% or less of structural units derived from ⁇ -olefin.
• the ethylene-based polymer (a2) is a copolymer of ethylene and ⁇ -olefin, the greater the amount of structural units derived from ethylene, the more preferable.
• the ethylene-based polymer (a2) may be a wax.
• the content of the ultra-high molecular weight ethylene polymer (a1) in the ethylene polymer composition (A) is preferably 20 to 60 parts by mass, and more preferably 30 to 50 parts by mass (wherein the total amount of the ultra-high molecular weight ethylene polymer (a1) and the ethylene polymer (a2) is 100 parts by mass).
• the content of the ethylene polymer (a2) in the ethylene polymer composition (A) is preferably 40 to 80 parts by mass, and more preferably 50 to 70 parts by mass (wherein the total amount of the ultra-high molecular weight ethylene polymer (a1) and the ethylene polymer (a2) is 100 parts by mass).
• the melt fluidity of the ethylene-based polymer composition (A) can be made relatively high. Therefore, the moldability of the ethylene-based polymer composition (A) and the resin composition (X) containing the ethylene-based polymer composition (A) tends to be good.
• the ethylene-based polymer composition (A) and the resin composition (X) containing the ethylene-based polymer composition (A) can sufficiently obtain the wear resistance derived from the ultra-high molecular weight ethylene polymer (a1).
• the wear resistance of the ethylene-based polymer composition (A) and the resin composition (X) containing the ethylene-based polymer composition (A) tends to be good, and the wear resistance of the molded product obtained from the resin composition (X) tends to be excellent.
• the ethylene-based polymer composition (A) preferably satisfies one or more of the requirements (A-a) and (A-b).
• the ethylene polymer composition (A) has an intrinsic viscosity [ ⁇ ] of preferably 3.0 to 15 dl/g, more preferably 3.0 to 10 dl/g, and further preferably 5.0 to 10 dl/g, measured in decalin solvent at 135° C. Details of the method for measuring the intrinsic viscosity [ ⁇ ] of the ethylene polymer composition (A) are as described in the Examples. When the intrinsic viscosity [ ⁇ ] in a decalin solvent at 135 ° C. is 3.0 dl / g or more, the wear resistance of the ethylene polymer composition (A) and the resin composition (X) containing the ethylene polymer composition (A) is good.
• the molded article obtained from the resin composition (X) also tends to have excellent wear resistance.
• the intrinsic viscosity [ ⁇ ] in a decalin solvent at 135 ° C. is 15 dl / g or less, the fluidity of the ethylene polymer composition (A) does not decrease, so the moldability of the resin composition (X) containing the ethylene polymer composition (A) tends to be good. That is, when the intrinsic viscosity [ ⁇ ] of the ethylene polymer composition (A) in a decalin solvent at 135 ° C. satisfies the above range, the resin composition (X) has high melt fluidity to such an extent that molding processing is easy, while also having good wear resistance.
• the density of the ethylene-based polymer composition (A) is preferably 930 to 980 kg/m 3 , more preferably 940 to 980 kg/m 3.
• the density of the ethylene-based polymer composition (A) is 930 kg/m 3 or more, the crystallinity of the ethylene-based polymer (a2) tends to be high enough to prevent the surface slippage of the ethylene-based polymer (a2) from being impaired. Therefore, the obtained ethylene-based polymer composition (A) and the resin composition (X) containing the ethylene-based polymer composition (A) tend to have excellent abrasion resistance.
• the obtained ethylene-based polymer composition (A) is excellent in lightness and processability.
• the obtained resin composition (X) also tends to have excellent lightness and processability.
• the method for measuring the density of the ethylene-based polymer composition (A) is as described in the Examples.
• the method for producing the ethylene polymer composition (A) is not particularly limited as long as it is a production method that can contain the ultrahigh molecular weight ethylene polymer (a1) and the ethylene polymer (a2) in a predetermined ratio.
• Preferred methods include the following methods (M-1) to (M-5).
• Method (M-1) A method of producing an ultra-high molecular weight ethylene polymer (a1) and an ethylene polymer (a2) in advance in the presence of an olefin polymerization catalyst, and then blending the ultra-high molecular weight ethylene polymer (a1) and the ethylene polymer (a2).
• Method (M-2) A method for producing an ethylene polymer by a multi-stage polymerization method including at least two steps, namely, a first step of producing an ultra-high molecular weight ethylene polymer (a1) in the presence of an olefin polymerization catalyst, and a second step of producing an ethylene polymer (a2).
• Method (M-3) A method for producing an ethylene polymer by a multi-stage polymerization method including at least two steps, namely, a first step of producing an ethylene polymer (a2) in the presence of an olefin polymerization catalyst, and a second step of producing an ultra-high molecular weight ethylene polymer (a1). Note that the second step is carried out in the presence of the ethylene polymer (a2) produced in the first step.
• Method (M-5) One or more selected from ultra-high molecular weight ethylene polymers (a1) and ethylene polymers (a2) are blended with the ethylene polymer composition (A) obtained by the methods (M-2), (M-3) and (M-4).
• the ultra-high molecular weight ethylene polymer (a1) and the ethylene polymer (a2) can be produced by polymerizing a monomer containing ethylene in the presence of a known olefin polymerization catalyst described in, for example, WO2008/013144 or WO2010/074073 under polymerization conditions such that the ethylene polymer composition (A) has desired physical properties.
• the methods (M-1) to (M-3) are more preferred, and the methods (M-2) and (M-3) using a multi-stage polymerization method are more preferred, and the method (M-2) in which the ultra-high molecular weight ethylene polymer (a1) is produced in the first step is even more preferred.
• the multi-stage polymerization method is used, the ultra-high molecular weight ethylene polymer (a1) and the ethylene polymer (a2) contained in the ethylene polymer composition (A) are compatible with each other, and dispersibility is improved, so that it is easy to achieve both abrasion resistance and moldability, which is preferable.
• the compatibility between the ultra-high molecular weight ethylene polymer (a1) and the ethylene polymer (a2) is improved, so the methods (M-4) and (M-5) are more preferred than the method (M-1).
• the olefin such as ethylene used in the polymerization can be any of the various olefins described in the sections on ultra-high molecular weight ethylene polymer (a1) and ethylene polymer (a2) without any restrictions.
• the resin composition (X), the ethylene-based polymer composition (A), the ultrahigh molecular weight ethylene-based polymer (a1), and the ethylene-based polymer (a2) (referred to as a resin composition, a polymer, etc. according to one embodiment of the present invention) may use, as a raw material (e.g., monomers such as ethylene and ⁇ -olefin), only raw materials derived from biomass, only raw materials derived from fossil fuel, or both raw materials derived from biomass and raw materials derived from fossil fuel.
• the biomass-derived raw material is a raw material made from any (renewable) natural raw material or its residue, such as plant-derived or animal-derived raw material including fungi, yeast, algae, and bacteria.
• a raw material containing about 1 ⁇ 10 ⁇ 12 of 14 C isotope as carbon and having a biomass carbon concentration (unit: pMC) of about 100 pMC measured in accordance with ASTM D6866 can be mentioned.
• Biomass-derived raw materials e.g., monomers such as ethylene and ⁇ -olefin
• the resin composition and polymer according to one embodiment of the present invention contain a structural unit derived from a raw material derived from biomass.
• the present invention contain a biomass-derived raw material, and so long as the production conditions, such as the polymerization catalyst, polymerization process, polymerization temperature, and kneading method, are equivalent, the molecular structure and physical properties, etc., other than the inclusion of 14C isotopes at a ratio of about 1 ⁇ 10 -12 to 1 ⁇ 10 -14 , are equivalent to those of a resin composition and polymer, etc. made from a fossil fuel-derived raw material. Therefore, it is considered that the performance of a resin composition and polymer, etc. containing a biomass-derived raw material is the same as that of a resin composition and polymer, etc. made from a fossil fuel-derived raw material.
• Carbon-based filler (B) which is one of the components constituting the resin composition (X), 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 molded body.
• 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 ⁇ m or more, more preferably 0.6 ⁇ m, and preferably 50 ⁇ m or less, more preferably 30 ⁇ m or less, and even more preferably 15 ⁇ m or less.
• the average diameter is 1 nm or more, it is possible to make the carbon nanotubes less likely to break during kneading, and if it is 20 nm or less, it is likely to be possible to increase the conductivity. If the average length is 0.5 ⁇ m or more, it is possible to increase the conductivity, and if it is 50 ⁇ m or less, it is likely to suppress the increase in viscosity during kneading, and to make kneading and molding easier.
• 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), a laser ablation method, etc. Commercially available carbon nanotubes may also be used.
• Carbon nanotubes tend to exhibit high conductivity in relatively small amounts compared to, for example, carbon black, but are expensive, so it is advantageous from a cost perspective if they can be used in smaller amounts.
• excellent conductivity can be obtained by using a resin composition (X) containing a carbon-based filler (B) and an ethylene-based polymer composition (A).
• resin composition (X) tends to provide high conductivity even with a small amount of carbon nanotubes.
• Conductive carbon black includes, for example, 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.
• the primary particle diameter of the conductive carbon black is preferably 0.005 ⁇ m or more, more preferably 0.01 ⁇ m or more, and preferably 1 ⁇ m or less, more preferably 0.2 ⁇ m or less.
• the primary particle diameter is the number-average particle diameter (Heywood diameter: diameter of a circle having the same area as the projected area of the primary particle) measured with an electron microscope or the like.
• Carbon fibers can be used as the carbon fiber, including, for example, polyacrylonitrile-based, rayon-based, pitch-based, polyvinyl alcohol-based, regenerated cellulose-based, and pitch-based carbon fibers made from mesophase pitch.
• Carbon fiber has an excellent specific strength, making it advantageous in applications where light weight and strength are important, such as for aircraft.
• the carbon fibers may be general-purpose fibers or high-strength fibers, and may be long fibers, short fibers, chopped fibers, or recycled fibers.
• a sizing agent (sizing agent) for carbon fibers for example, any of urethane-based emulsion, epoxy-based emulsion, nylon-based emulsion, and olefin-based emulsion can be used.
• the average length of the carbon fibers i.e., the average fiber length
• the average length of the carbon fibers 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.
• the average fiber length is 0.1 mm or more, the reinforcing effect of the carbon fibers on the mechanical properties tends to be fully expressed.
• the average fiber length is 15.0 mm or less, the dispersion of the carbon fibers in the ethylene-based polymer composition (A) tends to be good.
• the appearance of the molded product obtained by molding the resin composition (X) containing the ethylene-based polymer composition (A) and the carbon fibers tends to be good.
• the average diameter of the carbon fibers is preferably 3 ⁇ m or more, more preferably 5 ⁇ m or more, and preferably 30 ⁇ m or less, more preferably 21 ⁇ m or less, and even more preferably 19 ⁇ m or less.
• the average diameter of the carbon fibers is 3 ⁇ m or more, the carbon fibers are less likely to break during molding, and the impact strength of the resulting molded article tends to be high.
• the average diameter of the carbon fibers is 30 ⁇ m or less, the appearance of the molded article tends to be good, the aspect ratio of the carbon fibers does not decrease, and a sufficient reinforcing effect tends to be obtained in the mechanical properties such as rigidity and heat resistance of the molded article obtained from the resin composition (X).
• Carbon-based filler (B) can be used in one or more types.
• the resin composition (X) may contain other thermoplastic resins such as polyolefin-based resins, and resin additives (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 other than the ethylene-based polymer (a2), and the like) within the scope of the present invention.
• the total amount of the other components in the resin composition (X) is usually 5% by mass or less, preferably 2% by mass or less, and more preferably 1% by mass or less.
• the ratio of the total mass of the ultra-high molecular weight ethylene polymer (a1), the ethylene polymer (a2), and the carbon-based filler (B) in the resin composition (X) to the mass of the resin composition (X) is usually 95% by mass or more, preferably 98% by mass or more, and more preferably 99% by mass or more.
• the resin composition (X) satisfies the requirements (X-a) and (X-b).
• the resin composition (X) satisfies the requirements (X-a) and (X-b) and also satisfies one or more of the requirements (X-c) to (X-f).
• the resin composition (X) contains 100 parts by mass of the ethylene-based polymer composition (A) and 1 to 30 parts by mass of a carbon-based filler (B).
• the amount of the carbon-based filler (B) per 100 parts by mass of the ethylene-based polymer composition (A) is preferably 5 to 25 parts by mass, more preferably 5 to 15 parts by mass.
• the resin composition (X) contains the carbon-based filler (B) in the above range, it has high electrical conductivity, and the molded article obtained from the resin composition (X) also has high electrical conductivity. Furthermore, since the resin composition (X) contains the ethylene-based polymer composition (A) in the above range, it has high sliding properties, abrasion resistance, rigidity, and chemical resistance, and the molded article obtained from the resin composition (X) also has sliding properties, abrasion resistance, rigidity, and chemical resistance.
• the ratio ( ⁇ 1330 / ⁇ 13.3 ) is preferably 0.005 to 0.0265, more preferably 0.005 to 0.026, and even more preferably 0.010 to 0.0255. When the ratio ( ⁇ 1330 / ⁇ 13.3 ) is within the above range, it is easy to achieve a balance between the abrasion resistance and the injection moldability of the resin composition (X).
• the shear viscosity ⁇ 1330 of the resin composition (X) measured at a temperature of 250°C and a shear rate of 1330s -1 is preferably 100 to 300 Pa ⁇ s, more preferably 120 to 280 Pa ⁇ s, and even more preferably 150 to 250 Pa ⁇ s. Since the shear rate applied to the molten resin during injection molding may be relatively close to 1330s -1 , the shear viscosity ⁇ 1330 can be said to be an index of the injection moldability of the resin composition (X) in a temperature range around 250°C. In other words, when the shear viscosity ⁇ 1330 of the resin composition (X) is in the above range, the resin composition (X) is easily injection molded in a temperature range around 250°C.
• the shear viscosity ⁇ 13.3 of the resin composition (X) measured at a temperature of 250° C. and a shear rate of 13.3 s ⁇ 1 is preferably 5000 to 20000 Pa ⁇ s, more preferably 5500 to 18000 Pa ⁇ s, and even more preferably 6000 to 17000 Pa ⁇ s.
• the shear rate applied to the molten resin tends to be relatively close to 13.3 s ⁇ 1 . Therefore, the shear viscosity ⁇ 13.3 can be used as an index of the MFR of the resin composition (X).
• the resin composition (X) has an MFR, measured in accordance with JIS K 7210-1:2014 at 190°C under a load of 10 kg, of preferably 0.1 g/10 min or less, more preferably less than 0.1 g/10 min, even more preferably 0.001 g/10 min or more and less than 0.1 g/10 min, and particularly preferably in the range of 0.005 to 0.09 g/10 min.
• MFR measured in accordance with JIS K 7210-1:2014 at 190°C under a load of 10 kg
• the density of the resin composition (X) is preferably 990 to 1020 kg/m 3 , more preferably 995 to 1015 kg/m 3.
• the density of the resin composition (X) is 990 kg/m 3 or more, a molded article having excellent abrasion resistance can be obtained.
• the density of the resin composition (X) is 1020 kg/m 3 or less, a molded article having excellent light weight can be obtained.
• the method for measuring the density of the resin composition (X) is as described in the Examples.
• the resin composition (X) can be obtained by a conventionally known production method, for example, by dry blending the ethylene-based polymer composition (A), the carbon-based filler (B), and, if necessary, the other components. After dry blending, the mixture can be melt-kneaded in a single-screw or twin-screw extruder, extruded into a strand shape, and granulated into pellets to obtain pellets of the resin composition (X).
• the carbon-based filler (B) and the other components can be premixed with a polymer component such as the ethylene-based polymer composition (A) and added to the ethylene-based polymer composition (A) in the form of a master batch.
• the molded article according to one embodiment of the present invention includes the resin composition (X).
• a method for producing a molded article i.e., a method for molding the resin composition (X)
• a conventionally known molding method for polyolefins such as extrusion molding, injection molding, film molding, inflation molding, blow molding, extrusion blow molding, injection blow molding, press molding, vacuum molding, powder slush molding, calendar molding, foam molding, etc.
• the molded article containing the resin composition (X) is preferably obtained by molding the resin composition (X) by injection molding.
• a molded article containing a resin composition (X) containing carbon nanotubes as the carbon-based filler (B) is preferable.
• the molded article may be a molded article formed from resin composition (X), or may be a molded article having a portion, such as a surface layer, formed from resin composition (X).
• injection molded bodies tend to have lower electrical conductivity (higher volume resistivity) than press molded bodies, but molded bodies obtained by injection molding resin composition (X) tend to exhibit high electrical conductivity.
• resin composition (X) can form molded bodies with excellent electrical conductivity regardless of the molding method used.
• the volume resistivity is preferably 1 x 10 8 ⁇ cm or less, more preferably 1 x 10 6 ⁇ cm or less.
• molded articles made from resin composition (X) also have excellent mechanical properties.
• the specific abrasion rate (unit: 10-3 mm3 /(kgf.km)) is preferably 200 or less, more preferably 160 or less, even more preferably 150 or less, and particularly preferably 140 or less.
• molded articles include household products for daily necessities and recreational use, general industrial products, industrial products, etc. Examples include home appliance material parts, communication device parts, electric parts, electronic parts, automobile parts, other vehicle parts, ship and aircraft materials, machine mechanism parts, building materials, civil engineering materials, agricultural materials, power tool parts, food containers, films, sheets, and fibers.
• the molded article according to one embodiment of the present invention can be widely used in conventional polyethylene applications, but since it has an excellent balance of properties such as wear resistance, self-lubrication, impact strength, and thin-wall molding, it can be used in applications where these properties are required, such as metal coating materials (laminates) for steel pipes, electric wires, and automobile sliding door rails, pressure-resistant rubber hoses, gaskets for automobile doors, gaskets for clean room doors, automobile glass run channels, automobile weather strips, and various other rubber coating materials (laminates), linings for hoppers and chutes, and sliding materials for gears, bearings, rollers, tape reels, various guide rails, elevator rail guides, and various protective liner materials.
• metal coating materials laminates
• laminates for steel pipes, electric wires, and automobile sliding door rails
• pressure-resistant rubber hoses gaskets for automobile doors, gaskets for clean room doors, automobile glass run channels, automobile weather strips, and various other rubber coating materials (laminates)
• the molded article according to one embodiment of the present invention has excellent electrical conductivity, making it possible to suppress the electrostatic charge of various machine parts and sliding members, and is suitable for use in applications requiring antistatic properties.
• the density of the ethylene polymer composition (A) before the addition of the carbon-based filler was measured by a density gradient method in accordance with ASTM D 1505.
• the density of the ethylene polymer (a2) was also measured by the same method.
• Catalyst Preparation Example 1 Preparation of solid titanium catalyst component In a 10 L reactor equipped with a stirrer that had been thoroughly purged with nitrogen, 4.0 L of purified hexane and 95 g of anhydrous magnesium chloride were added, and 350 ml of ethanol was added dropwise at room temperature over a period of 2 hours while stirring, followed by mixing at room temperature for about 1 hour. Next, 330 ml of diethylaluminum chloride was added dropwise over a period of 2 hours, and the mixture was mixed at room temperature for about 1 hour after the dropwise addition, followed by dropping 1.3 L of titanium tetrachloride over a period of 1 hour, and the reaction was carried out at 80°C for 1 hour.
• the solid portion was separated using a filter and washed twice with refined hexane to obtain a solid titanium catalyst component having a titanium content of 6.8% by weight, a magnesium content of 15% by weight, and a chlorine content of 60% by weight.
• Example 1 Production of ethylene-based polymer composition (A-1)] (First stage polymerization: polymerization of ultra-high molecular weight ethylene polymer (a1-1)) 12 L of purified n-decane was added to a 24 L autoclave that had been fully substituted with nitrogen, and the temperature was then raised to 50° C. 12 mmol of triethylaluminum and the solid titanium catalyst component (0.12 mmol in terms of titanium atoms) prepared in Catalyst Preparation Example 1 were added to the autoclave at 50° C.
• the catalyst inlet was then closed, and ethylene was introduced so that the internal pressure of the autoclave became 4.3 kg/cm 2 ⁇ G, and the first stage of polymerization was carried out at 45 to 46° C. After 45 minutes of ethylene introduction, the pressure was released and the temperature was lowered to room temperature. A part of the solid white polymer produced was separated and dried, and the intrinsic viscosity [ ⁇ ] was measured, which was 28.0 dl/g. This value is the intrinsic viscosity [ ⁇ ] (135° C., in decalin) of the ultra-high molecular weight ethylene polymer (a1-1) contained in the ethylene polymer (A-1).
• the weight of the obtained ethylene polymer composition (A-1) was 3460 g, and the intrinsic viscosity [ ⁇ ] (135°C, in decalin) of the ethylene polymer composition (A-1) was 7.4 dl/g, and the density was 966 kg/ m3 .
• the ethylene-based polymer (a2-1') corresponds to the polymer produced in the second-stage polymerization of the ethylene-based polymer composition (A-1), and therefore the intrinsic viscosity, density, and production amount of the ethylene-based polymer (a2-1') are the same as those of the ethylene-based polymer (a2-1).
• Carbon nanotubes manufactured by Nanosil, product name: Carbon Nanotube NC7000, average diameter: 9.5 nm, average length: 1.5 ⁇ m
• a master batch (C1) was prepared by kneading 15% by mass of the carbon-based filler (B-1) and 85% by mass of the ethylene polymer composition (A-1) obtained in Production Example 1 in a twin-screw extruder.
• Preparation Example 1 Production of Ethylene-Based Resin Composition (X-1)] 40% by mass of the ethylene polymer composition (A-1) obtained in Production Example 1 and 60% by mass of the master batch (C1) were mixed and kneaded in a twin-screw extruder to produce an ethylene resin composition (X-1).
• the ethylene resin composition (X-1) was extruded into a strand shape and granulated into pellets. Furthermore, various physical properties of the obtained pellets were measured.
• the shear viscosity of the ethylene resin composition (X-1) was measured using a capillary rheometer: Capillograph 1D manufactured by Toyo Seiki Seisakusho, Ltd. The conditions were a resin temperature of 250°C, a preheating time of 6 minutes, a barrel diameter of ⁇ 10 mm, and shear viscosities were measured at shear rates of 13.3 sec -1 and 1330 sec -1 . The results are shown in Table 1.
• Example 2 Production of ethylene polymer composition (A-2)] The first and second polymerization stages and measurements were carried out under the same conditions as in Production Example 1, except that the internal pressure of the first autoclave was 4.6 kg/ cm2 ⁇ G, and the solid white polymer produced was separated and dried. The weight of the resulting ethylene-based polymer composition (A-2) was 3,550 g, and the intrinsic viscosity [ ⁇ ] (135° C., in decalin) of the ethylene-based polymer composition (A-2) was 8.3 dl/g and the density was 966 kg/ m3 .
• the intrinsic viscosity [ ⁇ ] of the solid white polymer produced in the first stage i.e., the intrinsic viscosity of the ultra-high molecular weight ethylene polymer (a1-2), 135° C., in decalin
• the weight of the obtained ethylene-based polymer (a2-2') was 2156 g
• the intrinsic viscosity [ ⁇ ] (135°C, in decalin) was 1.1 dl/g
• the density was 970 kg/ m3 .
• the intrinsic viscosity, density, and production amount of the ethylene-based polymer (a2-2') were the same as those of the ethylene-based polymer (a2-2) contained in the ethylene-based polymer composition (A-2). From the mass ratio of the polymers, the content of the ultra-high molecular weight ethylene polymer (a1-2) in the ethylene polymer composition (A-2) was calculated to be 39 mass %.
• a master batch (C2) containing carbon-based filler (B-1) A master batch (C2) was prepared in the same manner as in the preparation of the master batch (C1), except that the ethylene polymer composition (A-2) was used instead of the ethylene polymer composition (A-1).
• Preparation Example 2 Production of ethylene-based resin composition (X-2)] Except for using 40% by mass of the ethylene polymer composition (A-2) and 60% by mass of the master batch (C2), a composition was produced, and an injection molded article was produced and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 1.
• Example 3 Production of ethylene polymer composition (A-3)
• the first and second polymerization stages and measurements were carried out under the same conditions as in Production Example 1, except that the internal pressure of the first autoclave was set to 4.1 kg/ cm2 ⁇ G, and the solid white polymer produced was separated and dried.
• the weight of the resulting ethylene-based polymer composition (A-3) was 3,650 g, and the intrinsic viscosity [ ⁇ ] (135° C., in decalin) of the ethylene-based polymer composition (A-3) was 6.9 dl/g and the density was 966 kg/ m3 .
• the intrinsic viscosity [ ⁇ ] of the solid white polymer produced in the first stage i.e., the intrinsic viscosity of the ultra-high molecular weight ethylene polymer (a1-3), 135° C., in decalin
• the weight of the obtained ethylene-based polymer (a2-3') was 2313 g
• the intrinsic viscosity [ ⁇ ] (135°C, in decalin) was 1.1 dl/g
• the density was 970 kg/ m3 .
• the intrinsic viscosity, density, and production amount of the ethylene-based polymer (a2-3') were the same as those of the ethylene-based polymer (a2-3) contained in the ethylene-based polymer composition (A-3). From the mass ratio of the polymers, the content of the ultra-high molecular weight ethylene polymer (a1-3) in the ethylene polymer composition (A-3) was calculated to be 37 mass %.
• a master batch (C3) was prepared in the same manner as in the preparation of the master batch (C1), except that the ethylene polymer composition (A-3) was used instead of the ethylene polymer composition (A-1).
• Preparation Example 3 Production of ethylene-based resin composition (X-3)] Except for using 40% by mass of the ethylene polymer composition (A-3) and 60% by mass of the master batch (C3), a composition was produced, and an injection-molded article was produced and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 1.
• Example 4 Production of ethylene polymer composition (A-4)
• the first and second polymerization stages and measurements were carried out under the same conditions as in Production Example 1, except that the internal pressure of the first autoclave was 3.6 kg/ cm2 ⁇ G, and the solid white polymer produced was separated and dried.
• the weight of the resulting ethylene-based polymer composition (A-4) was 3,170 g, and the intrinsic viscosity [ ⁇ ] (135° C., in decalin) of the ethylene-based polymer composition (A-4) was 5.2 dl/g and the density was 967 kg/ m3 .
• the intrinsic viscosity [ ⁇ ] of the solid white polymer produced in the first stage i.e., the intrinsic viscosity of the ultra-high molecular weight ethylene polymer (a1-4), 135° C., in decalin
• the weight of the obtained ethylene-based polymer (a2-4') was 2148 g
• the intrinsic viscosity [ ⁇ ] (135°C, in decalin) was 1.1 dl/g
• the density was 970 kg/ m3 .
• the intrinsic viscosity, density, and production amount of the ethylene-based polymer (a2-4') were the same as those of the ethylene-based polymer (a2-4) contained in the ethylene-based polymer composition (A-4). From the mass ratio of the polymers, the content of the ultra-high molecular weight ethylene polymer (a1-4) in the ethylene polymer composition (A-4) was calculated to be 32 mass %.
• a master batch (C4) was prepared in the same manner as in the preparation of the master batch (C1), except that the ethylene polymer composition (A-4) was used instead of the ethylene polymer composition (A-1).
• Preparation Example 4 Production of ethylene-based resin composition (X-4)] Except for using 40% by mass of the ethylene polymer composition (A-4) and 60% by mass of the master batch (C4), a composition was produced, and an injection-molded article was produced and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 1.
• Example 5 Production of ethylene polymer composition (A-5)]
• the first and second polymerization stages and measurements were carried out under the same conditions as in Production Example 1, except that the internal pressure of the first autoclave was 5.0 kg/ cm2 ⁇ G, and the solid white polymer produced was separated and dried.
• the weight of the resulting ethylene-based polymer composition (A-5) was 3,660 g, and the intrinsic viscosity [ ⁇ ] (135° C., in decalin) of the ethylene-based polymer composition (A-5) was 9.3 dl/g and the density was 965 kg/ m3 .
• the intrinsic viscosity [ ⁇ ] of the solid white polymer produced in the first stage i.e., the intrinsic viscosity of the ultra-high molecular weight ethylene polymer (a1-5), 135° C., in decalin
• the weight of the obtained ethylene-based polymer (a2-5') was 2158 g
• the intrinsic viscosity [ ⁇ ] (135°C, in decalin) was 1.1 dl/g
• the density was 970 kg/ m3 .
• the intrinsic viscosity, density, and production amount of the ethylene-based polymer (a2-5') were the same as those of the ethylene-based polymer (a2-5) contained in the ethylene-based polymer composition (A-5). From the mass ratio of the polymers, the content of the ultra-high molecular weight ethylene polymer (a1-5) in the ethylene polymer composition (A-5) was calculated to be 41 mass %.
• a master batch (C5) was prepared in the same manner as in the preparation of the master batch (C1), except that the ethylene polymer composition (A-5) was used instead of the ethylene polymer composition (A-1).
• Preparation Example 5 Production of ethylene-based resin composition (X-5)] Except for using 40% by mass of the ethylene polymer composition (A-5) and 60% by mass of the master batch (C5), a composition was produced, and an injection-molded article was produced and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 1.
• the intrinsic viscosity [ ⁇ ] of the solid white polymer produced in the first stage i.e., the intrinsic viscosity of the ultra-high molecular weight ethylene polymer (a1-6), 135° C., in decalin
• the weight of the obtained ethylene-based polymer (a2-6') was 2468 g
• the intrinsic viscosity [ ⁇ ] (135°C, in decalin) was 1.1 dl/g
• the density was 970 kg/ m3 .
• the intrinsic viscosity, density, and production amount of the ethylene-based polymer (a2-6') were the same as those of the ethylene-based polymer (a2-6) contained in the ethylene-based polymer composition (A-6). From the mass ratio of the polymers, the content of the ultra-high molecular weight ethylene polymer (a1-6) in the ethylene polymer composition (A-6) was calculated to be 27 mass %.
• a master batch (C6) was prepared in the same manner as in the preparation of the master batch (C1), except that the ethylene polymer composition (A-6) was used instead of the ethylene polymer composition (A-1).
• the intrinsic viscosity [ ⁇ ] of the solid white polymer produced in the first stage i.e., the intrinsic viscosity of the ultra-high molecular weight ethylene polymer (a1-7), 135° C., in decalin
• the weight of the obtained ethylene-based polymer (a2-7') was 2394 g
• the intrinsic viscosity [ ⁇ ] (135°C, in decalin) was 1.1 dl/g
• the density was 970 kg/ m3 .
• the intrinsic viscosity, density, and production amount of the ethylene-based polymer (a2-7') were the same as those of the ethylene-based polymer (a2-7) contained in the ethylene-based polymer composition (A-7). From the mass ratio of the polymers, the content of the ultra-high molecular weight ethylene polymer (a1-7) in the ethylene polymer composition (A-7) was calculated to be 26 mass %.
• a master batch (C7) was prepared in the same manner as in the preparation of the master batch (C1), except that the ethylene polymer composition (A-7) was used instead of the ethylene polymer composition (A-1).
• Preparation Example 7 Production of ethylene-based resin composition (CX-7)] Except for using 40% by mass of the ethylene polymer composition (A-7) and 60% by mass of the master batch (C7), a composition was produced, and an injection-molded article was produced and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 1.
• the intrinsic viscosity [ ⁇ ] of the solid white polymer produced in the first stage i.e., the intrinsic viscosity of the ultra-high molecular weight ethylene polymer (a1-8), 135° C., in decalin
• the weight of the obtained ethylene-based polymer (a2-8') was 2526 g
• the intrinsic viscosity [ ⁇ ] (135°C, in decalin) was 1.1 dl/g
• the density was 970 kg/ m3 .
• the intrinsic viscosity, density, and production amount of the ethylene-based polymer (a2-8') were the same as those of the ethylene-based polymer (a2-8) contained in the ethylene-based polymer composition (A-8). From the mass ratio of the polymers, the content of the ultra-high molecular weight ethylene polymer (a1-8) in the ethylene polymer composition (A-8) was calculated to be 23 mass %.
• a master batch (C8) was prepared in the same manner as in the preparation of the master batch (C1), except that the ethylene polymer composition (A-8) was used instead of the ethylene polymer composition (A-1).
• Preparation Example 8 Production of ethylene-based resin composition (CX-8)] Except for using 40% by mass of the ethylene polymer composition (A-8) and 60% by mass of the master batch (C8), a composition was produced, and an injection-molded article was produced and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 1.
• the intrinsic viscosity [ ⁇ ] of the solid white polymer produced in the first stage i.e., the intrinsic viscosity of the ultra-high molecular weight ethylene polymer (a1-9), 135° C., in decalin
• the weight of the obtained ethylene-based polymer (a2-9') was 2224 g
• the intrinsic viscosity [ ⁇ ] (135°C, in decalin) was 1.1 dl/g
• the density was 970 kg/ m3 .
• the intrinsic viscosity, density, and production amount of the ethylene-based polymer (a2-9') were the same as those of the ethylene-based polymer (a2-9) contained in the ethylene-based polymer composition (A-9). From the mass ratio of the polymers, the content of the ultra-high molecular weight ethylene polymer (a1-9) in the ethylene polymer composition (A-9) was calculated to be 30 mass %.
• a master batch (C9) was prepared in the same manner as in the preparation of the master batch (C1), except that the ethylene polymer composition (A-9) was used instead of the ethylene polymer composition (A-1) and the kneading temperature was set to 270°C.
• the intrinsic viscosity [ ⁇ ] of the solid white polymer produced in the first stage i.e., the intrinsic viscosity of the ultra-high molecular weight ethylene polymer (a1-10), 135° C., in decalin
• the weight of the obtained ethylene-based polymer (a2-10') was 2438 g
• the intrinsic viscosity [ ⁇ ] (135°C, in decalin) was 1.1 dl/g
• the density was 970 kg/ m3 .
• the intrinsic viscosity, density, and production amount of the ethylene-based polymer (a2-10') were the same as those of the ethylene-based polymer (a2-10) contained in the ethylene-based polymer composition (A-10). From the mass ratio of the polymers, the content of the ultra-high molecular weight ethylene polymer (a1-10) in the ethylene polymer composition (A-10) was calculated to be 28 mass %.
• a master batch (C10) was prepared in the same manner as in the preparation of the master batch (C1), except that the ethylene polymer composition (A-10) was used instead of the ethylene polymer composition (A-1).
• Preparation Example 10 Production of ethylene-based resin composition (CX-10)] Except for using 40% by mass of the ethylene polymer composition (A-10) and 60% by mass of the master batch (C10), a composition was produced, and an injection-molded article was produced and various physical properties were measured in the same manner as in Example 1. The results are shown in Table 1.
• the ethylene polymer composition (A-11') and an ethylene polymer (manufactured by Prime Polymer Co., Ltd., product name Hi-Zex 1700JP) (a2-11-2) having an intrinsic viscosity [ ⁇ ] of 1.1 dl/g (135°C, in decalin) and a density of 965 kg/ m3 were melt-blended in a ratio of 49/51 to obtain pellets of the ethylene polymer composition (A-11).
• a master batch (C11) was prepared in the same manner as in the preparation of the master batch (C1), except that 75 mass% of the ethylene-based polymer composition (A-11) was used instead of the ethylene-based polymer composition (A-1), and 10 mass% of a wax (polyethylene wax, corresponding to the ethylene-based polymer (a2)) was additionally used.

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