Crosslinked body, its manufacturing method and use

Abstract

To provide a crosslinked body having mechanical strength and elasticity suitable for a covering material for a wire and a skin material for an automobile, and has high crosslinking density, a method for manufacturing a crosslinked body which enables reduction in an irradiation amount and shortage of irradiation time of an electron beam, and use of a crosslinked body such as a covering material for a wire which is excellent in a balance between elongation and strength.SOLUTION: A crosslinked body is obtained by crosslinking an ethylene-1-butene copolymer (A) satisfying all the following requirements (i) to (v), or a resin composition containing the ethylene-1-butene copolymer (A). (i) Content of a structural unit derived from ethylene of 70-99.9 mol%; (ii) 0.1-5.0 pieces of unsaturated bonds per 1,000 carbon atoms; (iii) MFR10 / MFR2.16 of 7-20; (iv) density of 0.850-0.910 g / cm3; and (v) melt flow rate (MFR2.16) of 0.01-200 g / 10 min.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a crosslinked product of an olefin resin suitable for use as a covering material or skin material for electric wires or cables, and to a method for producing the same and uses thereof. [Background technology]

[0002] Coating materials for electric wires or cables, skin materials for automobiles, and the like are required to have flexibility and heat resistance suitable for use at high temperatures. Crosslinked resins such as olefin-based resins have excellent heat resistance and are therefore suitable as coating materials for electric wires or cables (hereinafter also simply referred to as "coating materials for electric wires"). As a means for obtaining an electric wire coated with a crosslinked material, a method is known in which a coating layer is formed with a resin and the coating layer is irradiated with an electron beam to crosslink the resin in the coating layer.

[0003] When crosslinking the coating layer by irradiation with electron beams, a large amount of crosslinking agent has been added to increase crosslinking efficiency, and a large amount of antioxidant has been added to prevent oxidation due to electron beam irradiation, but there is a problem that the added components bleed out over time. There is also a problem that the crosslinking on the surface becomes insufficient due to oxidation by oxygen in the air, and that the crosslinking inside becomes insufficient. To solve these problems, a method of adding a specific antioxidant, a method of blocking oxygen, a method of irradiating electron beams in stages, and the like have been proposed (see Patent Documents 1 to 4).

[0004] However, conventional crosslinking by electron beam irradiation has problems such as the need for a high-energy electron beam irradiation device to perform sufficient electron beam irradiation, which increases the size of the equipment, and the need to spend a sufficient irradiation time, which limits the production speed. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Unexamined Patent Publication No. 58-145743 [Patent Document 2] JP 2006-19417 A [Patent Document 3] JP 2009-218035 A [Patent Document 4] Japanese Patent Application Publication No. 54-139686 Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present invention is to provide a crosslinked product having a high crosslink density as well as mechanical strength and elasticity suitable for use in, for example, covering materials for electric wires and skin materials for automobiles; to provide a method for producing a crosslinked product that allows for a reduction in the amount of electron beam irradiation and a shortened irradiation time; and to provide uses of the crosslinked product, such as covering materials for electric wires, that have an excellent balance of elongation and strength. [Means for solving the problem]

[0007] The present invention relates to, for example, the following [1] to

[11] . [1] An ethylene / 1-butene copolymer (A) satisfying all of the following requirements (i) to (v), or a crosslinked body obtained by crosslinking a resin composition containing the ethylene / 1-butene copolymer (A): (i) When the total of the structural unit (i) derived from ethylene and the structural unit (ii) derived from 1-butene is taken as 100 mol %, the content of the structural unit (i) is 70 to 99.9 mol %, and the content of the structural unit (ii) is 0.1 to 30 mol %. (ii) 1 The total number of vinyl double bonds, vinylidene double bonds, di-substituted olefin double bonds and tri-substituted olefin double bonds per 1000 carbon atoms as determined by H-NMR is in the range of 0.1 to 5.0. (iii) MFR 10 / MFR 2.16 is in the range of 7 to 20. (However, MFR 10 is the melt flow rate measured at 190°C under a load of 10 kg according to the method of ASTM D1238, and MFR 2.16is the melt flow rate measured at 190°C under a load of 2.16 kg according to the method of ASTM D1238. (iv) Density is 0.850 to 0.910 g / cm 3 is in the range. (v) Melt flow rate (MFR) measured at 190°C under a load of 2.16 kg according to the method of ASTM D1238 2.16 ) is in the range of 0.01 to 200 g / 10 min. [2] A molded article containing the crosslinked body described in [1] above. [3] A crosslinked foam containing the crosslinked product described in [1] above. [4] A covering material for an electric wire or cable, comprising the crosslinked product according to [1] above. [5] An electric wire or cable having a coating layer made of the crosslinked product described in [1] above. [6] The electric wire or cable according to [5], wherein the coating layer is an outer layer of the electric wire or cable. [7] An automobile skin material containing the crosslinked product according to [1] above. [8] A heat-shrinkable tube containing the crosslinked product described in [1] above. [9] A heat shrinkable film containing the crosslinked product described in [1] above.

[10] A method for producing a crosslinked product, comprising a step of crosslinking, by electron beam, an ethylene / 1-butene copolymer (A) which satisfies all of the following requirements (i) to (v), or a resin composition containing the ethylene / 1-butene copolymer (A): (i) When the total of the structural unit (i) derived from ethylene and the structural unit (ii) derived from 1-butene is taken as 100 mol %, the content of the structural unit (i) is 70 to 99.9 mol %, and the content of the structural unit (ii) is 0.1 to 30 mol %. (ii) 1 The total number of vinyl double bonds, vinylidene double bonds, di-substituted olefin double bonds and tri-substituted olefin double bonds per 1000 carbon atoms as determined by H-NMR is in the range of 0.1 to 5.0. (iii) MFR 10 / MFR 2.16 is in the range of 7 to 20. (However, MFR 10is the melt flow rate measured at 190°C under a load of 10 kg according to the method of ASTM D1238, and MFR 2.16 is the melt flow rate measured at 190°C under a load of 2.16 kg according to the method of ASTM D1238. (iv) Density is 0.850 to 0.910 g / cm 3 is in the range. (v) Melt flow rate (MFR) measured at 190°C under a load of 2.16 kg according to the method of ASTM D1238 2.16 ) is in the range of 0.01 to 200 g / 10 min.

[11] A method for producing an electric wire or cable, comprising a step of forming a coating layer of an electric wire or cable by the method for producing a crosslinked body according to

[10] above. Effect of the Invention

[0008] According to the present invention, it is possible to provide a crosslinked product having a high crosslinking density as well as mechanical strength and elasticity suitable for use as a covering material for electric wires, a skin material for automobiles, etc. Furthermore, according to the present invention, it is possible to provide a method for producing a crosslinked product that allows a reduction in the amount of electron beam irradiation and a shortening of the irradiation time, and uses of the crosslinked product such as a covering material for electric wires having an excellent balance between elongation and strength. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The present invention will now be described. [Crosslinked body] The crosslinked product of the present invention is a crosslinked product obtained by crosslinking the ethylene / 1-butene copolymer (A) or a resin composition containing the ethylene / 1-butene copolymer (A).

[0010] Ethylene-1-butene copolymer (A) The ethylene-1-butene copolymer (A) is a copolymer having structural units derived from ethylene and structural units derived from 1-butene, and satisfies all of the requirements (i) to (v) described below. The ethylene / 1-butene copolymer (A) may contain structural units derived from other than structural units derived from ethylene and 1-butene, such as structural units derived from propylene and an α-olefin having 5 to 20 carbon atoms, and structural units derived from a non-conjugated diene having a vinyl group. In the present invention, it is preferred that the ethylene / 1-butene copolymer (A) is composed only of structural units derived from ethylene and structural units derived from 1-butene, since the polymer can be easily produced and there is less gel in the polymer.

[0011] <Requirement (i)> (i) When the total of the structural unit (i) derived from ethylene and the structural unit (ii) derived from 1-butene is taken as 100 mol%, the content of the structural unit (i) derived from ethylene is 70 to 99.9 mol%, and the content of the structural unit (ii) derived from 1-butene is 0.1 to 30 mol%. The upper limit of the content of the structural unit (i) derived from ethylene is usually 99.9 mol%, preferably 98 mol%, more preferably 95 mol%, and the lower limit is usually 70 mol%, preferably 75 mol%, more preferably 78 mol%. The upper limit of the content of the structural unit (ii) derived from 1-butene is usually 30 mol%, preferably 25 mol%, more preferably 22 mol%, and the lower limit is usually 0.1 mol%, preferably 2 mol%, more preferably 5 mol%. When the structural unit (i) and the structural unit (ii) satisfy the above range, a crosslinked body having an excellent balance between elongation and strength is easily obtained, which is preferable.

[0012] <Requirement (ii)> (ii) 1 The total number of vinyl double bonds, vinylidene double bonds, di-substituted olefin double bonds and tri-substituted olefin double bonds (hereinafter also referred to as the total number of double bonds or the amount of unsaturated bonds) per 1000 carbon atoms as determined by H-NMR is 0.1 to 5.0.

[0013] The lower limit of the total of the double bonds is usually 0.1, preferably 0.15, more preferably 0.2, even more preferably 0.3, and particularly preferably 0.4. When the total of the double bonds is equal to or more than the above lower limit, the crosslinking properties are excellent when irradiated with electron beams, and a sufficient crosslinking fraction can be achieved with a small amount of electron beam irradiation, which is preferable. On the other hand, the upper limit of the total of the double bonds is usually 5.0, preferably 4.0, more preferably 3.0, even more preferably 2.5, and particularly preferably 2.0. When the total of the double bonds is equal to or less than the above upper limit, it is preferable because it can prevent excessive crosslinking or cleavage of the polymer main chain in the process before electron beam irradiation, and can suppress deterioration due to heat, light, etc. when the crosslinked product is formed.

[0014] The amount of unsaturated bonds, which is the total amount of vinyl double bonds, vinylidene double bonds, di-substituted olefin double bonds, and tri-substituted olefin double bonds, can be measured by the method described in detail in the measurement and evaluation methods described in the Examples below.

[0015] <Requirement (iii)> (iii) MFR 10 / MFR 2.16 is in the range of 7 to 20, preferably 7.2 to 15, and more preferably 7.5 to 12. 10 is the melt flow rate (g / 10 min) measured at 190°C under a load of 10 kg according to the method of ASTM D1238, and MFR2.16 is the melt flow rate (g / 10 min) measured at 190°C under a load of 2.16 kg according to the method of ASTM D1238.

[0016] MFR 10 / MFR 2.16 is a value that is considered to be one of the indicators of the degree of long chain branching of a copolymer, and MFR 10 / MFR 2.16 A value in the above range is specified as having long chain branching. 10 / MFR 2.16 A lower value indicates less long chain branching. 10 / MFR 2.16When the value is 7 or more, the moldability and the shape stability of the crosslinked product are excellent. 10 / MFR 2.16 When the value is 20 or less, the resulting crosslinked body has excellent physical properties such as strength.

[0017] <Requirement (iv)> (iv) Density is 0.850 to 0.910 g / cm 3 The density of the ethylene-1-butene copolymer (A) is preferably in the range of 0.855 g / cm 3 More preferably, 0.857 g / cm 3 More preferably, 0.858 g / cm 3 or more, and preferably 0.909 g / cm 3 Less than or equal to 0.908 g / cm 3 More preferably, 0.907 g / cm 3 The density of the ethylene-1-butene copolymer (A) is a value measured at 23°C in accordance with ASTM D1505. When the density satisfies such a range, the resulting crosslinked product, molded product, and crosslinked foam are preferred because they have excellent physical properties such as a balance between flexibility and strength, and a balance between rigidity and impact strength.

[0018] <Requirement(v)> (v) Melt flow rate (MFR) measured at 190°C under a load of 2.16 kg according to the method of ASTM D1238 2.16 The melt flow rate (MFR 2.16 ) is preferably 0.05 g / 10 min or more, more preferably 0.08 g / 10 min or more, even more preferably 0.1 g / 10 min or more, particularly preferably 0.2 g / 10 min, and is preferably 100 g / 10 min or less, more preferably 40 g / 10 min or less, even more preferably 25 g / 10 min or less, particularly preferably 5 g / 10 min or less.

[0019] Melt flow rate (MFR 2.16The larger the molecular weight, the smaller the MFR. The method for adjusting the molecular weight will be described later in the section on the production of ethylene-1-butene copolymer (A). 2.16 It is preferable that the MFR is equal to or less than the above upper limit in that the strength of the obtained molded article or crosslinked foam is improved. 2.16 It is preferable that the above lower limit value or more is in terms of improving the fluidity when the ethylene / 1-butene copolymer (A) or a resin composition containing the ethylene / 1-butene copolymer (A) is melt-molded.

[0020] <Other characteristics> The ethylene / 1-butene copolymer (A) according to the present invention satisfies the above-mentioned requirements (i) to (v) and, although not particularly limited thereto, preferably also satisfies the following properties:

[0021] Mw / Mn The ethylene-1-butene copolymer (A) according to the present invention is not particularly limited, but the molecular weight distribution (Mw / Mn) calculated as the ratio of the weight average molecular weight Mw to the number average molecular weight Mn measured by gel permeation chromatography (GPC) is preferably 1.5 to 3.5, more preferably 1.5 to 3.0. Mw / Mn can be adjusted to the above range by appropriately selecting a polymerization catalyst as described in the section on olefin polymerization catalysts. In addition, it is preferable that Mw / Mn is within the above range in terms of improving the melt moldability and the strength of the resulting molded product or crosslinked foam.

[0022] Melting point (Tm) The ethylene / 1-butene copolymer (A) according to the present invention has, but is not particularly limited to, a melting point (Tm) determined from a DSC endothermic curve of preferably 40° C. or higher, more preferably 50° C. or higher, even more preferably 55° C. or higher, and preferably 130° C. or lower, more preferably 120° C. or lower, even more preferably 110° C. or lower. The melting point of the ethylene / 1-butene copolymer (A) within the above range is preferred in terms of the balance between rebound resilience and heat shrinkage.

[0023] Method for producing ethylene-1-butene copolymer (A) The ethylene / 1-butene copolymer (A) according to the present invention may be any copolymer as long as it satisfies the above-mentioned requirements (i) to (v), and its production method is not particularly limited. For example, the copolymer can be suitably produced by copolymerizing ethylene and 1-butene in the presence of an olefin polymerization catalyst.

[0024] <Olefin polymerization catalyst> The ethylene-1-butene copolymer (A) according to the present invention has the above-mentioned properties. There is no limitation on the production method thereof. For example, it can be produced by copolymerizing ethylene and 1-butene in the presence of an olefin polymerization catalyst comprising the following catalytic components [A] and [B]: [A] A bridged metallocene compound represented by the following general formula [I]:

[0025] [ka] In formula [I], M represents a transition metal, p represents the valence of the transition metal, X may be the same or different, and each represents a hydrogen atom, a halogen atom, or a hydrocarbon group, R 1 and R 2 represents a π-electron conjugated ligand coordinated to M, which may be the same or different, and Q represents R 1 and R 2 represents a divalent group that crosslinks [B] (b-1) organoaluminum oxy compound, (b-2) a compound that reacts with the metallocene compound [A] to form an ion pair, and (b-3) Organoaluminum compounds At least one compound selected from the group consisting of:

[0026] The copolymerization can be carried out, for example, by solution polymerization of monomers containing ethylene and 1-butene in the presence of such an olefin polymerization catalyst at a temperature of 0 to 200° C. in the coexistence of a solvent.

[0027] However, the ethylene-1-butene copolymer (A) according to the present invention is not limited to the above-mentioned production method as long as it satisfies the above-mentioned properties. For example, a metallocene compound having a structure different from that of the above formula [I] may be used in the copolymerization, a co-catalyst other than the catalyst component [B] may be used, or two or more known types of ethylene copolymers may be used to prepare the copolymer by a technique such as reactor blending or physical blending.

[0028] The above-mentioned method for producing an ethylene-1-butene copolymer (A), which comprises copolymerizing a monomer containing ethylene and 1-butene in the presence of an olefin polymerization catalyst containing the catalyst components [A] and [B], will be further described below.

[0029] Catalyst component [A] The catalyst component [A] is a bridged metallocene compound represented by the above formula [I]. In the above formula [I], examples of the transition metal represented by M include Zr, Ti, Hf, V, Nb, Ta and Cr, and the preferred transition metal is Zr, Ti or Hf, and the more preferred transition metal is Zr or Hf.

[0030] In general formula [I], R 1 and R 2 Examples of the π-electron conjugated ligand represented by the formula (1) include ligands having an η-cyclopentadienyl structure, an η-benzene structure, an η-cycloheptatrienyl structure, and an η-cyclooctatetraene structure, and particularly preferred ligands are those having an η-cyclopentadienyl structure. Examples of the ligand having an η-cyclopentadienyl structure include a cyclopentadienyl group, an indenyl group, a hydrogenated indenyl group, and a fluorenyl group. These groups may be further substituted with a halogen atom, a hydrocarbon group such as an alkyl, an aryl, an aralkyl, an alkoxy, or an aryloxy, a hydrocarbon group-containing silyl group such as a trialkylsilyl group, a linear or cyclic alkylene group, or the like.

[0031] In the general formula [I], R represented by Q 1 and R 2The group bridging the two is not particularly limited as long as it is a divalent group, and examples thereof include a straight-chain or branched-chain alkylene group, an unsubstituted or substituted cycloalkylene group, an alkylidene group, an unsubstituted or substituted cycloalkylidene group, an unsubstituted or substituted phenylene group, a silylene group, a dialkyl-substituted silylene group, a germyl group, and a dialkyl-substituted germyl group.

[0032] Specific examples of catalyst component [A] include the metallocene complexes used in the examples described below, but the catalyst component [A] is not limited to these compounds. Such a catalyst component [A] is preferably used together with a catalyst component [B] as a catalyst for olefin polymerization.

[0033] ·Catalyst component [B] When the above-mentioned catalyst component [A] is used as a component of an olefin polymerization catalyst for producing an ethylene-1-butene copolymer (A), the olefin polymerization catalyst preferably contains a catalyst component [B] composed of at least one compound selected from (b-1) an organoaluminum oxy compound, (b-2) a compound that reacts with the catalyst component [A] to form an ion pair, and (b-3) an organoaluminum compound. Here, from the viewpoints of polymerization activity and properties of the ethylene-1-butene copolymer produced, the catalyst component [B] is preferably used in any one of the following embodiments [c1] to [c4]. [c1] (b-1) Organoaluminum oxy compounds only [c2] (b-1) organoaluminum oxy compounds and (b-3) organoaluminum compounds, [c3] (b-2) a compound that reacts with the catalyst component [A] to form an ion pair, and (b-3) an organoaluminum compound, [c4] (b-1) an organoaluminum oxy compound and (b-2) a compound which reacts with the catalyst component [A] to form an ion pair.

[0034] However, when a metallocene compound in which Q in the general formula [I] is a silylene group is used as the catalyst component [A], (b-2) a compound that reacts with the catalyst component [A] to form an ion pair is not used as the [B] component, and only [c1] and [c2] are used in the above-mentioned preferred [B] components; [c1] to [c4].

[0035] Each component that may constitute the catalyst component [B] will be specifically described below. (b-1) Organoaluminum oxy compounds As the organoaluminum oxy compound (b-1), a conventionally known aluminoxane can be used as it is. Specific examples include compounds represented by the following general formula [II] and / or general formula [III].

[0036] [ka] (In formula [II] or [III], R is a hydrocarbon group having 1 to 10 carbon atoms, and n is an integer of 2 or more.) In particular, methylaluminoxanes in which R is a methyl group and n is 3 or more, preferably 10 or more, are used. (An organoaluminumoxy compound in which R is a methyl group in general formula [II] or [III] may be referred to as "methylaluminoxane" hereinafter.)

[0037] As the organoaluminum oxy compound (b-1), it is also preferable to use a methylaluminoxane analogue that is soluble in a saturated hydrocarbon, such as a modified methylaluminoxane represented by the following general formula [IV].

[0038] [ka] (In formula [IV], R represents a hydrocarbon group having 2 to 20 carbon atoms, and m and n represent integers of 2 or more.) The modified methylaluminoxane represented by the general formula [IV] is prepared using trimethylaluminum and an alkylaluminum other than trimethylaluminum (the manufacturing method is disclosed in, for example, US4960878, US5041584, etc.), and is commercially produced by manufacturers such as Tosoh Finechem Corporation under the trade names MMAO and TMAO, which are prepared using trimethylaluminum and triisobutylaluminum, where R is an isobutyl group (see, for example, "Tosoh Research and Technology Report," Vol. 47, p. 55 (2003)).

[0039] Furthermore, as the organoaluminum oxy compound (b-1), a benzene-insoluble organoaluminum oxy compound exemplified in JP-A-2-78687 may be used, or a boron-containing organoaluminum oxy compound represented by the following general formula [V] may be used.

[0040] [ka] (In formula [V], R c R represents a hydrocarbon group having 1 to 10 carbon atoms. d may be the same or different and represent a hydrogen atom, a halogen atom, or a hydrocarbon group having 1 to 10 carbon atoms.) Incidentally, there is no problem if a small amount of an organoaluminum compound is mixed into the above-mentioned (b-1) organoaluminum oxy-compound.

[0041] (b-2) A compound that reacts with the catalyst component [A] to form an ion pair Examples of the compound (b-2) that reacts with the catalyst component [A] to form an ion pair (hereinafter, sometimes abbreviated as "ionic compound (b-2)") include Lewis acids, ionic compounds, borane compounds, and carborane compounds described in JP-T-1-501950, JP-T-1-502036, JP-A-3-179005, JP-A-3-179006, JP-A-3-207703, JP-A-3-207704, and USP 5321106. Furthermore, examples of the ionic compound (b-2) include heteropoly compounds and isopoly compounds.

[0042] In the present invention, the ionic compound (b-2) preferably used is a compound represented by the following general formula [VI].

[0043] [ka] In formula [VI], R e+ As for H + , carbenium cation, oxonium cation, ammonium cation, phosphonium cation, cycloheptyltrienyl cation, ferrocenium cation having a transition metal, etc. f ~R i may be the same or different and are organic groups, preferably aryl groups.

[0044] Specific examples of the carbenium cation include tri-substituted carbenium cations such as triphenylcarbenium cation, tris(methylphenyl)carbenium cation, and tris(dimethylphenyl)carbenium cation.

[0045] Specific examples of the ammonium cation include trialkylammonium cations such as trimethylammonium cation, triethylammonium cation, tri(n-propyl)ammonium cation, triisopropylammonium cation, tri(n-butyl)ammonium cation, and triisobutylammonium cation; N,N-dialkylanilinium cations such as N,N-dimethylanilinium cation, N,N-diethylanilinium cation, and N,N-2,4,6-pentamethylanilinium cation; and dialkylammonium cations such as diisopropylammonium cation and dicyclohexylammonium cation.

[0046] Specific examples of the phosphonium cation include triarylphosphonium cations such as triphenylphosphonium cation, tris(methylphenyl)phosphonium cation, and tris(dimethylphenyl)phosphonium cation.

[0047] Of the above, R e+ As the cation, a carbenium cation, an ammonium cation, etc. are preferred, and in particular, a triphenylcarbenium cation, an N,N-dimethylanilinium cation, and an N,N-diethylanilinium cation are preferred.

[0048] Specific examples of the ionic compound (b-2) which is a carbenium salt include triphenylcarbenium tetraphenylborate, triphenylcarbenium tetrakis(pentafluorophenyl)borate, triphenylcarbenium tetrakis(3,5-ditrifluoromethylphenyl)borate, tris(4-methylphenyl)carbenium tetrakis(pentafluorophenyl)borate, and tris(3,5-dimethylphenyl)carbenium tetrakis(pentafluorophenyl)borate.

[0049] Examples of the ionic compound (b-2) which is an ammonium salt include trialkyl-substituted ammonium salts, N,N-dialkylanilinium salts, and dialkylammonium salts.

[0050] Specific examples of the ionic compound (b-2) which is a trialkyl-substituted ammonium salt include triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri(n-butyl)ammonium tetraphenylborate, trimethylammonium tetrakis(p-tolyl)borate, trimethylammonium tetrakis(o-tolyl)borate, tri(n-butyl)ammonium tetrakis(pentafluorophenyl)borate, triethylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(pentafluorophenyl)borate, tripropylammonium tetrakis(2,4-dimethylphenyl)borate, tri(n-butyl)ammonium tetrakis(3,5-dimethylphenyl)borate, tri(n-butyl)ammonium tetrakis(4-trifluoromethylphenyl)borate, tri( n-butyl)ammonium tetrakis(3,5-ditrifluoromethylphenyl)borate, tri(n-butyl)ammonium tetrakis(o-tolyl)borate, dioctadecylmethylammonium tetraphenylborate, dioctadecylmethylammonium tetrakis(p-tolyl)borate, dioctadecylmethylammonium tetrakis(o-tolyl)borate, dioctadecylmethylammonium tetrakis(pentafluorophenyl)borate, dioctadecylmethylammonium tetrakis(2,4-dimethylphenyl)borate, dioctadecylmethylammonium tetrakis(3,5-dimethylphenyl)borate, dioctadecylmethylammonium tetrakis(4-trifluoromethylphenyl)borate, dioctadecylmethylammonium tetrakis(3,5-ditrifluoromethylphenyl)borate, dioctadecylmethylammonium and the like.

[0051] Specific examples of the ionic compound (b-2) which is an N,N-dialkylanilinium salt include N,N-dimethylanilinium tetraphenylborate, N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, N,N-dimethylanilinium tetrakis(3,5-ditrifluoromethylphenyl)borate, N,N-diethylanilinium tetraphenylborate, N,N-diethylanilinium tetrakis(pentafluorophenyl)borate, N,N-diethylanilinium tetrakis(3,5-ditrifluoromethylphenyl)borate, N,N-2,4,6-pentamethylanilinium tetraphenylborate, and N,N-2,4,6-pentamethylanilinium tetrakis(pentafluorophenyl)borate.

[0052] Specific examples of dialkylammonium salts include di(1-propyl)ammonium tetrakis(pentafluorophenyl)borate, dicyclohexylammonium tetraphenylborate, and the like.

[0053] As other ionic compounds (b-2), ionic compounds disclosed by the present applicant (JP-A-2004-51676) can also be used without any restrictions. The above ionic compounds (b-2) may be used alone or in combination of two or more.

[0054] (b-3) Organoaluminum compounds Examples of the organoaluminum compound (b-3) include an organoaluminum compound represented by the following general formula [VII] and an alkyl complex of a Group 1 metal and aluminum represented by the following general formula [VIII].

[0055] R a m Al(OR b ) n H p X q … [VII] (In formula [VII], R a and Rb may be the same as or different from each other, and represents a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms. X represents a halogen atom, m is a number where 0 < m ≦ 3, n is a number where 0 ≦ n < 3, p is a number where 0 ≦ p < 3, q is a number where 0 ≦ q < 3, and m + n + p + q = 3.)

[0056] Specific examples of the organoaluminum compound represented by the general formula [VII] include tri-n-alkylaluminum such as trimethylaluminum, triethylaluminum, tri-n-butylaluminum, trihexylaluminum, trioctylaluminum; tri-branched chain alkylaluminum such as triisopropylaluminum, triisobutylaluminum, tri-sec-butylaluminum, tri-tert-butylaluminum, tri-2-methylbutylaluminum, tri-3-methylhexylaluminum, tri-2-ethylhexylaluminum; tricycloalkylaluminum such as tricyclohexylaluminum, tricyclooctylaluminum; triarylaluminum such as triphenylaluminum, tritolylaluminum; dialkylaluminum hydride such as diisopropylaluminum hydride, diisobutylaluminum hydride; General formula (i-C4H9) x Al y (C5H 10 ) z (wherein x, y, and z are positive numbers, and z ≦ 2x.) and alkenylaluminum such as isoprenylaluminum represented by the formula; alkylaluminum alkoxide such as isobutylaluminum methoxide, isobutylaluminum ethoxide; dialkylaluminum alkoxide such as dimethylaluminum methoxide, diethylaluminum ethoxide, dibutylaluminum butoxide; alkylaluminum sesquialkoxide such as ethylaluminum sesquiethoxide, butylaluminum sesquibutoxide; General formula Ra 2.5 Al(OR b ) 0.5 Partially alkoxylated alkylaluminum having an average composition represented by the formula: Alkylaluminum aryloxides such as diethylaluminum phenoxide and diethylaluminum (2,6-di-t-butyl-4-methylphenoxide); Dialkylaluminum halides such as dimethylaluminum chloride, diethylaluminum chloride, dibutylaluminum chloride, diethylaluminum bromide, and diisobutylaluminum chloride; Alkyl aluminum sesquihalides such as ethyl aluminum sesquichloride, butyl aluminum sesquichloride, and ethyl aluminum sesquibromide; partially halogenated alkylaluminums, such as alkylaluminum dihalides, such as ethylaluminum dichloride; Dialkylaluminum hydrides such as diethylaluminum hydride and dibutylaluminum hydride; Other partially hydrogenated alkylaluminums, such as alkylaluminum dihydrides, such as ethylaluminum dihydride, propylaluminum dihydride, etc.; Examples of the aluminum compounds include partially alkoxylated and halogenated alkylaluminum compounds such as ethylaluminum ethoxy chloride, butylaluminum butoxy chloride, and ethylaluminum ethoxy bromide.

[0057] M 2 AlR a 4. [VIII] (In formula [VIII], M 2 indicates Li, Na or K, and R a represents a hydrocarbon group having 1 to 15 carbon atoms, preferably 1 to 4 carbon atoms.) and aluminum alkyl complexes of metals in Group 1 of the Periodic Table. Examples of such compounds include LiAl(C2H5)4, LiAl(C7H 15 ) 4 can be given as an example.

[0058] Compounds similar to the compound represented by the above general formula [VII] can also be used, such as organoaluminum compounds in which two or more aluminum compounds are bonded via nitrogen atoms, such as (C2H5)2AlN(C2H5)Al(C2H5)2.

[0059] As the (b-3) organoaluminum compound, trimethylaluminum and triisobutylaluminum are preferably used from the viewpoint of easy availability.

[0060] <Production of ethylene-1-butene copolymer (A)> The ethylene-1-butene copolymer (A) according to the present invention can be suitably produced by copolymerizing a monomer component containing ethylene and 1-butene in the presence of the above-mentioned olefin polymerization catalyst. The copolymerization can be carried out, for example, by solution polymerization in the presence of a solvent. The polymerization temperature is not particularly limited, but can be, for example, 140°C or higher, preferably 150°C or higher. When the copolymerization reaction is carried out at such a temperature, the MFR of the obtained ethylene-1-butene copolymer (A) is 10 / MFR 2.16 This is preferable because it is possible to increase the vinyl group content.

[0061] In the polymerization, the method of using each component and the order of addition may be selected arbitrarily. For example, the catalyst component [A] and the catalyst component [B] may be added to the polymerization vessel in any order. In the above process, two or more of each catalyst component may be pre-contacted.

[0062] When the ethylene-1-butene copolymer (A) according to the present invention is produced by copolymerizing a monomer component containing ethylene and 1-butene using the above-mentioned olefin polymerization catalyst, the catalyst component [A] is usually used in an amount of 10 -9 ~10 -1 Molar, preferably 10 -8 ~10-2 It is used in molar amounts.

[0063] Component (b-1) is used in an amount such that the molar ratio [(b-1) / (M)] of component (b-1) to the total transition metal atoms (M) in component [A] is usually 1 to 10,000, preferably 10 to 5,000. Component (b-2) is used in an amount such that the molar ratio [(b-2) / (M)] of component (b-2) to the total transition metal atoms (M) in component [A] is usually 0.5 to 50, preferably 1 to 20. Component (b-3) is used in an amount such that the amount is usually 0 to 5 mmol, preferably about 0 to 2 mmol, per liter of polymerization volume.

[0064] The molar ratio of ethylene to 1-butene charged here may be appropriately selected depending on the properties of the desired ethylene-1-butene copolymer (A) and is not particularly limited. Generally, the molar ratio of ethylene:1-butene is 10:90 to 99.9:0.1, preferably ethylene:1-butene is 30:70 to 99.9:0.1, and more preferably ethylene:1-butene is 50:50 to 95.0:5.0.

[0065] The ethylene-1-butene copolymer (A) according to the present invention is preferably composed only of structural units derived from ethylene and 1-butene, and it is desirable to use a monomer component consisting of only ethylene and 1-butene as a monomer component serving as a copolymerization raw material, but the monomer component may contain other copolymerization components within a range in which the resulting copolymer satisfies the above-mentioned requirements (i) to (v). Examples of the other monomer components include one or more α-olefins selected from propylene and α-olefins having 5 to 20 carbon atoms, and non-conjugated dienes having a vinyl group.

[0066] "Solution polymerization" preferably used for producing the ethylene-1-butene copolymer (A) is a general term for a method in which polymerization is carried out in a state where the polymer is dissolved in a hydrocarbon solvent inert to the copolymerization reaction. The polymerization temperature in the solution polymerization according to the present invention can usually be in the range of about 0 to 200°C, but is preferably 140°C or higher, more preferably 150°C or higher.

[0067] In the solution polymerization of the present invention, if the polymerization temperature is less than 0°C, the polymerization activity drops drastically, making it impractical in terms of productivity, and furthermore, the vinyl group content of the ethylene-1-butene copolymer (A) may drop. In addition, in the polymerization temperature range of 0°C or higher, as the temperature increases, the solution viscosity during polymerization drops, the heat of polymerization is easily removed, and furthermore, the vinyl group content of the ethylene-1-butene copolymer (A) increases. However, if the polymerization temperature exceeds 200°C, the polymerization activity may drop drastically. The ethylene-1-butene copolymer (A) of the present invention has a relatively high MFR 10 / MFR 2.16 Since the copolymerization is carried out at a relatively high temperature of 140° C. or higher, preferably 150° C. or higher, it is preferable to carry out the copolymerization at a relatively high temperature of 140° C. or higher, and more preferably 150° C. or higher.

[0068] The polymerization pressure is usually normal pressure to 10 MPa gauge pressure, preferably normal pressure to 8 MPa gauge pressure, and the copolymerization can be carried out by any of batch, semi-continuous, and continuous methods. The reaction time (average residence time when the copolymerization reaction is carried out by a continuous method) varies depending on conditions such as catalyst concentration and polymerization temperature and can be appropriately selected, but is usually 1 minute to 3 hours, preferably 10 minutes to 2.5 hours. It is also possible to carry out the polymerization in two or more stages with different reaction conditions. The molecular weight of the obtained ethylene-1-butene copolymer (A) can be adjusted by changing the hydrogen concentration in the polymerization system or the polymerization temperature. It can also be adjusted by the amount of the catalyst component [B] used. When hydrogen is added to the polymerization system, the amount is appropriately about 0.001 to 5,000 NL per kg of the ethylene-1-butene copolymer produced. The vinyl group amount of the obtained ethylene-1-butene copolymer (A) can be increased by increasing the polymerization temperature and minimizing the amount of hydrogen added.

[0069] In addition, the MFR of the obtained ethylene-1-butene copolymer (A) 10 / MFR 2.16is an index that indicates that the larger the value, the more the long-chain branched structure is contained, but in the case of coordination polymerization such as in the examples described later, it is believed that the long-chain branched structure in the ethylene-1-butene copolymer (A) is formed by the reinsertion of molecular chains (macromonomers) with terminal vinyl groups generated by β-hydrogen elimination reactions. Therefore, the MFR of the ethylene-1-butene copolymer (A) can be adjusted by increasing or decreasing the ratio of the macromonomer concentration to the ethylene concentration in the solution ([macromonomer] / [ethylene]). 10 / MFR 2.16 The value of can be controlled. In general, when the [macromonomer] / [ethylene] ratio is high, the amount of long chain branches in the ethylene polymer increases, and when the [macromonomer] / [ethylene] ratio is low, the amount of long chain branches in the ethylene polymer decreases. Specific methods for increasing or decreasing the [macromonomer] / [ethylene] ratio in the solution include the following methods [1] to [4].

[0070] [1] Polymerization temperature The higher the polymerization temperature, the easier the β-hydrogen elimination reaction occurs. Therefore, by increasing the polymerization temperature, the ratio of [macromonomer] / [ethylene] increases, and the amount of long chain branches in the ethylene copolymer increases. [2] Polymer concentration If the polymer concentration in the solution is increased, the macromonomer concentration also increases relatively, so that the ratio [macromonomer] / [ethylene] increases and the amount of long chain branches in the ethylene copolymer increases. [3] Ethylene conversion rate If the ethylene conversion rate is increased, the ethylene concentration in the solution decreases, so that the ratio [macromonomer] / [ethylene] increases and the amount of long chain branches in the ethylene copolymer increases. [4] Solvent type When the polymerization solvent is changed to a low boiling point solvent, the ethylene concentration in the solution decreases, so that the ratio [macromonomer] / [ethylene] increases and the amount of long chain branches in the ethylene-1-butene copolymer increases.

[0071] In addition, by controlling the chain transfer reaction to Al in addition to controlling the β-hydrogen elimination reaction, it is possible to increase or decrease the ratio (macromonomer / ethylene) and change the amount of long chain branches in the ethylene polymer.

[0072] The solvent used in the solution polymerization is usually an inert hydrocarbon solvent, preferably a saturated hydrocarbon having a boiling point of 50°C to 200°C under normal pressure. Specific examples include aliphatic hydrocarbons such as pentane, hexane, heptane, octane, decane, dodecane, and kerosene; and alicyclic hydrocarbons such as cyclopentane, cyclohexane, and methylcyclopentane. Aromatic hydrocarbons such as benzene, toluene, and xylene, and halogenated hydrocarbons such as ethylene chloride, chlorobenzene, and dichloromethane, are also included in the category of "inert hydrocarbon solvents" related to the high-temperature solution polymerization of the present invention, and the use of these is not limited thereto. As described above, in the high-temperature solution polymerization suitably employed in the production of the ethylene-1-butene copolymer (A) according to the present invention, not only the conventionally used organic aluminum oxy compounds that dissolve in aromatic hydrocarbons, but also modified methylaluminoxanes such as MMAO that dissolve in aliphatic and alicyclic hydrocarbons can be used. As a result, by using aliphatic and alicyclic hydrocarbons as the solvent for solution polymerization, it is possible to almost completely eliminate the possibility of aromatic hydrocarbons being mixed into the polymerization system or the ethylene-based polymer produced. In other words, the high-temperature solution polymerization method preferably employed for producing the ethylene-1-butene copolymer (A) according to the present invention has the characteristics of reducing the environmental load and minimizing the impact on human health.

[0073] In order to suppress the variation in physical properties, the ethylene / 1-butene copolymer (A) obtained by the polymerization reaction and other components added as desired are preferably melted by any method and kneaded, granulated, or the like.

[0074] resin composition The crosslinked product of the present invention may be a crosslinked product obtained by crosslinking only the above-mentioned ethylene / 1-butene copolymer (A), or may be a crosslinked product obtained by crosslinking a resin composition containing the ethylene / 1-butene copolymer (A) and other components. Components other than the ethylene / 1-butene copolymer (A) that may be contained in the resin composition according to the present invention are not particularly limited, and examples thereof include resin components other than the ethylene / 1-butene copolymer (A) and additives.

[0075] Examples of the resin component other than the ethylene-1-butene copolymer (A) include polyolefins other than the ethylene-1-butene copolymer (A), polystyrene, acrylic resins, polyesters, polyamides, styrene-based elastomers, (meth)acrylic elastomers, polyester-based elastomers, polyamide-based elastomers, etc. These resin components may be modified resins grafted to improve compatibility with the ethylene-1-butene copolymer (A), or may be used with the addition of a compatibilizer.

[0076] The additives include those known to be added to olefin resins, such as crosslinking agents, chemical foaming agents, flame retardant agents (flame retardants, flame retardant assistants), antioxidants, heat stabilizers, ultraviolet absorbers, weather stabilizers, antistatic agents, slip agents, antiblocking agents, crystal nucleating agents, pigments, dyes, lubricants, hydrochloric acid absorbers, and copper damage inhibitors.

[0077] As the crosslinking agent, any radical generator that acts as a crosslinking agent can be used without particular limitation, and organic peroxides are preferably used. Specific examples of organic peroxides include dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(t-butylperoxy)hexyne-3, 1,3-bis(t-butylperoxyisopropyl)benzene, 1,1-bis(t-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(t-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, t-butyl peroxybenzoate, t-butyl perbenzoate, t-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, and t-butylcumyl peroxide. Among these, dicumyl peroxide is preferred.

[0078] When the resin composition according to the present invention contains a crosslinking agent, the content thereof is preferably in the range of 0.1 to 2.0 parts by mass, more preferably 0.3 to 1.8 parts by mass, and even more preferably 0.6 to 1.6 parts by mass, based on 100 parts by mass of the ethylene-1-butene copolymer (A). When a resin composition containing such an amount of crosslinking agent is used, a crosslinked product having an appropriate crosslinked structure can be obtained even by a crosslinking method other than electron beam crosslinking. In the present invention, since the ethylene-1-butene copolymer (A) satisfying all of the above requirements (i) to (v) is subjected to crosslinking, a sufficient crosslink density can be obtained even when a resin composition containing a reduced amount of crosslinking agent is used.

[0079] When the resin composition contains a crosslinking agent, it is also preferable to contain a crosslinking assistant as necessary together with the crosslinking agent. Examples of the crosslinking assistant include peroxy crosslinking assistants such as sulfur, p-quinone dioxime, p,p'-dibenzoylquinone dioxime, N-methyl-N-4-dinitrosoaniline, nitrosobenzene, diphenyl guanidine, and trimethylolpropane-N,N'-m-phenylenedimaleimide; polyfunctional methacrylate monomers such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, and allyl methacrylate; polyfunctional vinyl monomers such as vinyl butyrate and vinyl stearate; divinylbenzene, triallyl cyanurate (TAC), and triallyl isocyanurate (TAIC). Among them, triallyl cyanurate (TAC) and triallyl isocyanurate (TAIC) are preferred.

[0080] In the resin composition, the crosslinking aid is desirably used in an amount such that the mass ratio of the crosslinking aid to the crosslinking agent [crosslinking aid / crosslinking agent] is 1 / 30 to 5 / 1, preferably 1 / 20 to 3 / 1, more preferably 1 / 15 to 2 / 1, and particularly preferably 1 / 10 to 1 / 1. When the crosslinked product of the present invention is obtained by electron beam crosslinking, it is also preferable that the resin composition does not contain a crosslinking agent or a crosslinking assistant.

[0081] The content of components other than the ethylene / 1-butene copolymer (A) in the resin composition is not particularly limited as long as it is within a range that does not impair the object of the present invention. However, it is generally 1,000 parts by mass or less, preferably 800 parts by mass or less, and more preferably in the range of 1 to 700 parts by mass, per 100 parts by mass of the ethylene / 1-butene copolymer (A).

[0082] The resin composition according to the present invention can be produced by a known method. For example, the ethylene-1-butene copolymer (A) and each of the other components are simultaneously or successively charged into a mixer such as a Henschel mixer, a V-type blender, a tumbler mixer, or a ribbon blender, mixed, and melt-kneaded with a multi-screw extruder such as a single-screw extruder or a twin-screw extruder, or a kneader, a Banbury mixer, or the like, to obtain the resin composition. In particular, when an apparatus having excellent kneading performance such as a multi-screw extruder, a kneader, or a Banbury mixer is used, a high-quality resin composition in which each component is more uniformly dispersed can be obtained.

[0083] crosslinked body The crosslinked body of the present invention is obtained by crosslinking the above-mentioned ethylene / 1-butene copolymer (A) or a resin composition containing the ethylene / 1-butene copolymer (A). The crosslinked body of the present invention can usually be obtained by premolding the above-mentioned ethylene / 1-butene copolymer (A) or a resin composition containing the ethylene / 1-butene copolymer (A) and then crosslinking the premolded product. Examples of the premolding method include known molding methods for molding into a desired shape, such as extrusion molding, injection molding, inflation molding, injection molding, blow molding, extrusion blow molding, press molding, vacuum molding, calendar molding, roll processing, bead foam molding, batch foam molding, press foam molding, atmospheric secondary foam molding, injection foam molding, extrusion foam molding, foam blow molding, core-back foam molding, and pressure foam molding.

[0084] The method for crosslinking the above-mentioned ethylene-1-butene copolymer (A) or the resin composition containing the ethylene-1-butene copolymer (A) is not particularly limited, and may be performed by heating using a crosslinking agent, or by radiation crosslinking in which crosslinking is performed by irradiating with radiation such as electron beams, X-rays, γ-rays, α-rays and β-rays. Among radiation crosslinking, electron beam crosslinking is preferred. The crosslinked product according to the present invention is preferably produced by radiation crosslinking, particularly electron beam crosslinking, and in this case, the ethylene-1-butene copolymer (A) or the resin composition containing the ethylene-1-butene copolymer (A) to be crosslinked may not contain a crosslinking agent. When producing a crosslinked product by electron beam crosslinking, an example of the method is to preform the ethylene-1-butene copolymer (A) or the ethylene-1-butene copolymer (A) as described above, and then irradiate it with an electron beam. The electron beam irradiation can be carried out so that the ethylene / 1-butene copolymer (A) or the ethylene / 1-butene copolymer (A) has an absorbed dose of usually 0.5 to 36 Mrad, preferably 0.5 to 20 Mrad, and more preferably 1 to 10 Mrad.

[0085] The crosslinked product according to the present invention has excellent mechanical strength and elasticity, and is well balanced between elongation and strength, and can therefore be suitably used for applications such as various molded products, crosslinked foams, covering materials for electric wires or cables, automotive skin materials, automotive interior materials, heat insulating materials, heat shrinkable tubes, heat shrinkable films, etc. The covering material for electric wires or cables is preferably a covering material that forms a covering layer that becomes the outer layer of an electric wire or cable.

[0086] [Method of manufacturing crosslinked body] The method for producing a crosslinked body of the present invention includes a step of subjecting an ethylene / 1-butene copolymer (A) satisfying all of the above-mentioned requirements (i) to (v) or a resin composition containing the ethylene / 1-butene copolymer (A) to an electron beam crosslinking. Preferably, the method for producing a crosslinked body of the present invention includes a step of premolding an ethylene / 1-butene copolymer (A) satisfying all of the above-mentioned requirements (i) to (v) or a resin composition containing the ethylene / 1-butene copolymer (A) by a known method, and irradiating the obtained premolded body with an electron beam to perform electron beam crosslinking. The electron beam crosslinking step may be performed without performing premolding, may be performed simultaneously with premolding, or may be performed after premolding.

[0087] In the step of electron beam crosslinking, the electron beam can be irradiated so that the absorbed dose is usually 0.5 to 36 Mrad, preferably 0.5 to 20 Mrad, and more preferably 1 to 10 Mrad.

[0088] In the method for producing a crosslinked product of the present invention, the ethylene-1-butene copolymer (A) satisfying all of the requirements (i) to (v) or a resin composition containing the copolymer is subjected to electron beam crosslinking, so that the crosslinking efficiency by electron beam crosslinking is good and sufficient crosslink density can be achieved even with a smaller amount of electron beam irradiation than before. Therefore, in the method for producing a crosslinked product of the present invention, it is possible to produce a crosslinked product by reducing the amount of electron beam irradiation and energy consumption, and to shorten the time spent on crosslinking by electron beam irradiation (irradiation time). This also makes it possible to obtain effects such as crosslinking without using a large-capacity facility for electron beam irradiation, thereby making it possible to miniaturize the crosslinking facility, and shortening the crosslinking time to increase the production rate of the crosslinked product. EXAMPLES

[0089] The present invention will be described in more detail below based on examples, but the present invention is not limited to these examples.

[0090] [Evaluation of copolymer properties] The physical properties of the ethylene-1-butene copolymer were evaluated as follows. <Content of each constituent unit> 13 It was determined by C-NMR spectrum analysis. 13 C-NMR measurements were performed under the following conditions: Apparatus: Bruker Biospin AVANCEIII500 CryoProbe Prodigy type nuclear magnetic resonance apparatus, measurement nucleus: 13C (125MHz), measurement mode: single pulse proton broadband decoupling, pulse width: 45° (5.00μsec), number of points: 64k, measurement range: 250ppm (-55~195ppm), repetition time: 5.5sec, number of accumulations: 512, measurement solvent: orthodichlorobenzene / benzene-d6 (4 / 1 v / v), sample concentration: ca. 60mg / 0.6mL, measurement temperature: 120°C, window function: exponential (BF: 1.0Hz), chemical shift reference: benzene-d6 (128.0ppm).

[0091] <density> The value was determined at 23°C in accordance with ASTM D1505. <mfr> Measured at 190°C in accordance with ASTM D1238. The measured value under a load of 2.16 kg is the MFR. 2.16 , the measured value with a 10 kg load is MFR 10 It was decided.

[0092] <Unsaturated bond amount> 1 The amount of unsaturated bonds (double bonds) was quantified by H-NMR spectrum analysis as the total amount of vinyl double bonds, vinylidene double bonds, di-substituted olefin double bonds, and tri-substituted olefin double bonds per 1,000 carbon atoms. 1 H-NMR measurements were performed under the following conditions. Apparatus: Bruker Biospin AVANCEIII cryo-500 magnetic resonance apparatus, measurement interval: 1H (500MHz), measurement mode: single pulse, pulse width: 45° (5.00μsec), number of points: 32k, measurement range: 20ppm (-6ppm~14ppm), repetition time: 7.0sec, number of accumulations: 64, measurement solvent: orthodichlorobenzene-d4, sample concentration: ca. 20mg / 0.6mL, measurement temperature: 120°C, window function: exponential (BF: 0.15Hz), chemical shift reference: main chain methylene signal (1.20ppm). Here, vinyl double bonds, vinylidene double bonds, disubstituted olefin double bonds and trisubstituted olefin double bonds are observed as signals derived from double bonds. From the integrated intensity of each signal, the amount of unsaturated bonds was quantified as the total amount of vinylidene double bonds, di-substituted olefinic double bonds, and tri-substituted olefinic double bonds.

[0093] [ka]

[0094] In each formula, * indicates a bond to an atom other than a hydrogen atom. The peaks of the hydrogen atoms a to e are observed near the following positions. Hydrogen atom a peak: 4.60 ppm Hydrogen atom b peak: 4.85 ppm Hydrogen atom c peak: 5.10 ppm Hydrogen atom d peak: 5.25 ppm Hydrogen atom e peak: 5.70 ppm The quantitative formula for the amount of double bonds is as follows: Amount of vinyl double bonds = {(integral intensity of signal b) + (integral intensity of signal e)} / 3 Amount of vinylidene double bonds = (integral intensity of signal a) / 2 Amount of disubstituted olefinic double bonds = (integral intensity of signal d) / 2 Amount of trisubstituted olefinic double bonds = (integral intensity of signal c)

[0095] From these results, the total number of double bond units (amount of unsaturated bonds) per 1000 carbon atoms (1000C) was calculated as the total amount of vinylidene double bonds, di-substituted olefin double bonds, and tri-substituted olefin double bonds.

[0096] <Molecular weight distribution (Mw / Mn)> The chromatographic properties were determined by gel permeation chromatography (GPC) in an orthodichlorobenzene solvent at 140°C. A gel permeation chromatograph Alliance GPC-2000 manufactured by Waters was used, and the measurements were performed as follows. The separation columns were two TSKgel GNH6-HT and two TSKgel GNH6-HTL, each with a diameter of 7.5 mm and a length of 300 mm, the column temperature was 140°C, the mobile phase was o-dichlorobenzene (Wako Pure Chemical Industries) and 0.025 mass% BHT (Takeda Pharmaceuticals) as an antioxidant, and the mobile phase was moved at 1.0 ml / min, the sample concentration was 15 mg / 10 ml, the sample injection amount was 500 μl, and a differential refractometer was used as the detector. The standard polystyrene had molecular weights of Mw<1000 and Mw>4×10 6 For the 1000≦Mw≦4×10 6 The material used was manufactured by Pressure Chemical Company.

[0097] <Melting point (Tm)> Using a differential scanning calorimeter (SII DSC220), approximately 5.0 mg of the sample was heated from 30°C to 200°C at a heating rate of 10°C / min under a nitrogen atmosphere and held at that temperature for 10 minutes. It was then cooled to 30°C at a heating rate of 10°C / min, held at that temperature for 5 minutes, and then heated to 200°C at a heating rate of 10°C / min. The endothermic peak observed during this second heating was taken as the melting peak, and the temperature at which the melting peak appeared was determined as the melting point (Tm).

[0098] [Evaluation of crosslinked bodies] <Gel fraction> Approximately 1 g of sample was cut out and precisely weighed. It was immersed in 100 cc of xylene and treated at 110°C for 24 hours, filtered, and the residue was dried and precisely weighed. The gel fraction was calculated by dividing the weight by the weight before treatment. <Hardness> Type D durometer hardness (duro hardness) was measured in accordance with JIS K6253. <Breaking stress, grip elongation, gauge elongation, elastic modulus> In accordance with ASTM D638, the sample shape was a No. 4 dumbbell and the measurement was performed at a tensile speed of 200 mm / min.

[0099] [Production Example 1] <Preparation of ethylene-1-butene copolymer (A-1)> Copolymerization of ethylene and 1-butene was carried out continuously at a polymerization temperature of 135°C and a polymerization pressure of 2.5MPaG in a 100L stainless steel polymerization vessel equipped with an impeller (agitation speed: 250 rpm). Dehydrated and purified hexane was continuously fed from the side of the polymerization vessel at a rate of 53L, ethylene at 9kg, 1-butene at 8kg per hour, hydrogen at 10NL, di(p-tolyl)methylene(cyclopentadienyl)(octamethyloctahydrodibenzofluorenyl)zirconium dichloride at 0.018mmol, methylaluminoxane at 9mmol in terms of aluminum, and triisobutylaluminum at 4mmol per hour. The hexane solution of the ethylene-1-butene copolymer thus produced was continuously discharged through an outlet provided on the side wall of the polymerization vessel while adjusting the opening of the liquid level control valve to maintain the amount of solution in the polymerization vessel at 28L. The resulting hexane solution of ethylene / 1-butene copolymer was introduced into a heater and heated to 180°C. 80 mL of methanol was added every hour as a catalyst deactivator to terminate the polymerization. The solution was then continuously transferred to a degassing process under reduced pressure and dried to obtain ethylene / 1-butene copolymer (A-1).

[0100] The ethylene-1-butene copolymer (A-1) obtained as above has a density d of 885 kg / m 3 , M.F.R. 2.16 0.5g / 10min, MFR 10 The polymerization rate was 4.6 g / 10 min, the amount of unsaturated bonds was 0.53 / 1000 C, Mw / Mn was 2.0, the melting point was 66° C., and the yield was 18 kg per hour. The physical properties are shown in Table 1.

[0101] [Production Example 2] <Preparation of catalyst solution> 18.4 mg of triphenylcarbenium(tetrakispentafluorophenyl)borate was taken and dissolved in 5 ml of toluene to prepare a toluene solution with a concentration of 0.004 mM / ml.

[0102] 1.8 mg of [dimethyl(t-butylamido)(tetramethyl-η5-cyclopentadienyl)silane]titanium dichloride was dissolved in 5 ml of toluene to prepare a toluene solution with a concentration of 0.001 mM / ml.

[0103] At the start of polymerization, 0.38 ml of a toluene solution of triphenylcarbenium (tetrakispentafluorophenyl) borate and 0.38 ml of a toluene solution of [dimethyl(t-butylamido) (tetramethyl-η5-cyclopentadienyl) silane] titanium dichloride were taken, and 4.24 ml of toluene for dilution was added to prepare 5 ml of a toluene solution in which triphenylcarbenium (tetrakispentafluorophenyl) borate was 0.002 mM / L in terms of B and [dimethyl(t-butylamido) (tetramethyl-η5-cyclopentadienyl) silane] titanium dichloride was 0.0005 mM / L in terms of Ti.

[0104] <Preparation of ethylene-1-butene copolymer (A'-2)> 750 ml of heptane was added to a 1.5-liter SUS autoclave equipped with an agitator, which had been thoroughly substituted with nitrogen, at 23°C, and then 10 g of 1-butene and 250 ml of hydrogen were added while rotating the agitator and cooling with ice. Next, the autoclave was heated to 100°C, and further pressurized with ethylene so that the total pressure was 6 kg. When the internal pressure of the autoclave reached 6 kg, 1.0 ml of a 1.0 mM / ml hexane solution of triisobutylaluminum (TIBA) was added with nitrogen. Then, 5 ml of the catalyst solution prepared as described above was added with nitrogen to start polymerization. After that, the temperature of the autoclave was adjusted to 100°C for 5 minutes, and ethylene was directly supplied so that the pressure was 6 kg. Five minutes after the start of polymerization, 5 ml of methanol was added to the autoclave with a pump to stop the polymerization, and the autoclave was depressurized to atmospheric pressure. 3 liters of methanol was poured into the reaction solution while stirring. The resulting polymer containing the solvent was dried at 130°C for 13 hours at 600 torr to obtain 10 g of ethylene-1-butene copolymer (A'-2).

[0105] The ethylene-1-butene copolymer (A'-2) obtained as above has a density d of 885 kg / m 3 , M.F.R. 2.16 1.2g / 10min, MFR 10 The viscosity was 7.9 g / 10 min, the amount of unsaturated bonds was 0.07 / 1000 C, Mw / Mn was 2.4, and the melting point was 66° C. The physical properties are shown in Table 1.

[0106] [Table 1]

[0107] [Example 1] The ethylene / 1-butene copolymer (A-1) obtained in Production Example 1 was heated and molded for 7 minutes in a press molding machine set at 190° C. to obtain a pressed sheet having a thickness of 2 mm.

[0108] Next, the prepared press sheet was subjected to electron beam crosslinking using a scanning electron beam irradiation device (EPS-750 manufactured by Nissin High Voltage Co., Ltd.). The crosslinking conditions were a voltage of 650 kV, a temperature of 10 to 40°C, and an electron beam irradiation dose of 10 kGy on both sides of the press sheet. The physical properties were evaluated using the obtained crosslinked sheet. The results are shown in Table 2.

[0109] [Examples 2 to 4] A crosslinked sheet was produced and evaluated in the same manner as in Example 1, except that the crosslinking step by electron beam crosslinking was carried out at the electron beam irradiation dose shown in Table 2. The results are shown in Table 2.

[0110] [Reference examples 1~4] A crosslinked sheet was produced and evaluated in the same manner as in Example 1, except that the ethylene / 1-butene copolymer (A-1) in Example 1 was replaced with the ethylene / 1-butene copolymer (A'-2) obtained in Production Example 2, and the crosslinking step by electron beam crosslinking was carried out at the electron beam irradiation dose shown in Table 2. The results are shown in Table 2.

[0111] [Table 2]

[0112] The results of the above examples and reference examples (see Table 2) show that the ethylene-1-butene copolymer (A-1) satisfying all of the requirements (i) to (v) can achieve sufficient crosslinking even with a small dose of electron beam irradiation without using a crosslinking agent, and can give a crosslinked product having mechanical properties with an excellent balance between hardness and elasticity. [Industrial Applicability]

[0113] The crosslinked product according to the present invention can be used as various molded products, and is suitable as a covering material for electric wires or cables, a skin material for automobiles, a heat-shrinkable tube, a heat-shrinkable film, etc.< / mfr>

Claims

1. An ethylene / 1-butene copolymer (A) which satisfies all of the following requirements (i) to (v), or a crosslinked product obtained by crosslinking, with an electron beam, a resin composition which contains the ethylene / 1-butene copolymer (A) and does not contain a crosslinking agent or a crosslinking aid: (i) When the total of the structural unit (i) derived from ethylene and the structural unit (ii) derived from 1-butene is taken as 100 mol %, the content of the structural unit (i) is 70 to 99.9 mol %, and the content of the structural unit (ii) is 0.1 to 30 mol %. (ii) 1 The total number of vinyl double bonds, vinylidene double bonds, di-substituted olefin double bonds and tri-substituted olefin double bonds per 1000 carbon atoms as determined by H-NMR is in the range of 0.1 to 5.

0. (iii) MFR 10 / M.F.R. 2.16 is in the range of 7 to 20. (However, MFR 10 is the melt flow rate measured at 190°C under a load of 10 kg according to the method of ASTM D1238, and MFR 2.16 is the melt flow rate measured at 190°C under a load of 2.16 kg according to the method of ASTM D1238. (iv) density is 0.850 to 0.910 g / cm 3 is in the range. (v) Melt flow rate (MFR) measured at 190° C. under a load of 2.16 kg according to the method of ASTM D1238. 2.16 ) is in the range of 0.01 to 200 g / 10 min.

2. A molded article comprising the crosslinked article according to claim 1.

3. A crosslinked foam comprising the crosslinked product according to claim 1.

4. A covering material for electric wire or cable, comprising the crosslinked product according to claim 1.

5. An electric wire or cable having a covering layer made of the crosslinked product according to claim 1.

6. The wire or cable according to claim 5 , wherein the coating layer is an outer layer of the wire or cable.

7. A skin material for an automobile, comprising the crosslinked product according to claim 1.

8. A heat-shrinkable tube comprising the crosslinked product according to claim 1.

9. A heat shrinkable film comprising the crosslinked product according to claim 1.

10. A method for producing a crosslinked product, comprising the step of crosslinking, with an electron beam, an ethylene / 1-butene copolymer (A) that satisfies all of the following requirements (i) to (v), or a resin composition that contains the ethylene / 1-butene copolymer (A) but does not contain a crosslinking agent or a crosslinking aid: (i) When the total of the structural unit (i) derived from ethylene and the structural unit (ii) derived from 1-butene is taken as 100 mol %, the content of the structural unit (i) is 70 to 99.9 mol %, and the content of the structural unit (ii) is 0.1 to 30 mol %. (ii) 1 The total number of vinyl double bonds, vinylidene double bonds, di-substituted olefin double bonds and tri-substituted olefin double bonds per 1000 carbon atoms as determined by H-NMR is in the range of 0.1 to 5.

0. (iii) MFR 10 / M.F.R. 2.16 is in the range of 7 to 20. (However, MFR 10 is the melt flow rate measured at 190°C under a load of 10 kg according to the method of ASTM D1238, and MFR 2.16 is the melt flow rate measured at 190°C under a load of 2.16 kg according to the method of ASTM D1238. (iv) density is 0.850 to 0.910 g / cm 3 is in the range. (v) Melt flow rate (MFR) measured at 190° C. under a load of 2.16 kg according to the method of ASTM D1238. 2.16 ) is in the range of 0.01 to 200 g / 10 min.

11. The method for producing a crosslinked body described in claim 10, wherein the electron beam crosslinking step is a step of irradiating with an electron beam at an electron beam exposure dose of 100 kGy or less.

12. The method for producing a crosslinked body described in claim 10, wherein the electron beam crosslinking step is a step of irradiating with an electron beam at an electron beam dose of 50 to 100 kGy.

13. The method for producing a crosslinked body described in claim 10, wherein the electron beam crosslinking step is a step of irradiating with an electron beam so that the absorbed dose is 0.5 to 36 Mrad.

14. A method for producing an electric wire or cable, comprising a step of forming a coating layer of the electric wire or cable by the method for producing a crosslinked body according to any one of claims 10 to 13.

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