Copolymer composition for conveyor belt and use thereof

Abstract

To obtain a copolymer composition for a conveyor belt, preferable for obtaining a conveyor belt having high wear resistance, furthermore having high thermal aging resistance.SOLUTION: A copolymer composition for a conveyor belt is provided, including: copolymer composition comprising a specific ethylene-α-olefin-non-conjugated polyene copolymer (S) that has constitutional units derived from ethylene (A), constitutional units derived from α-olefins with a carbon atom number of 3 to 20 (B), and constitutional units derived from specific non-conjugated polyenes (C); an ethylene-α-olefin copolymer (F) that contains constitutional units derived from ethylene (A) and constitutional units derived from α-olefins with a carbon number of 3 to 20 (B'); and an onium salt (K), wherein the content of the onium salt (K) is in the range of 0.2 to 80 pts.mass with respect to the total of 100 pts.mass of the ethylene-α-olefin-non-conjugated polyene copolymer (S) and the ethylene-α-olefin copolymer (F).SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a copolymer composition for a conveyor belt and its uses.

Background Art

[0002] In various industrial fields such as steel, coal, and cement, belt conveyor devices are used as means for transporting articles. In particular, there are many cases where high-temperature articles of about 150 to 250 ° C, such as clinker, are transported by a belt conveyor device. In response to such a situation, in order to minimize maintenance work and extend the service life, a conveyor belt having excellent heat aging resistance and abrasion resistance is required.

[0003] As a method for improving the heat aging resistance, abrasion resistance, etc. of a conveyor belt, it has been proposed to use a rubber composition containing an ethylene-1-octene copolymer and an ethylene-propylene copolymer (Patent Document 1).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in recent years, the requirements for higher abrasion resistance of conveyor belts have been increasing, and it is desired that a rubber composition for a heat-resistant conveyor belt that replaces conventional products has heat resistance, mechanical properties, and processability equivalent to or better than those of conventional products. Regarding this, even in the prior art, although attempts have been made to improve the abrasion resistance of conveyor belts, there is still room for improvement in heat aging resistance. An object of the present invention is to obtain a copolymer composition for a conveyor belt suitable for obtaining a conveyor belt having high abrasion resistance and high heat aging resistance.

Means for Solving the Problems

[0006] As a result of investigations to solve the above problems, the present inventors have found that the above problems can be solved by a specific composition containing an onium salt, and have completed the present invention. Further, the present inventors have also found that the composition is excellent in tear resistance. The present invention relates to the following [1] to

[13] . [1] An ethylene·α-olefin·non-conjugated polyene copolymer (S), An ethylene·α-olefin copolymer (F), An onium salt (K) and the ethylene·α-olefin·non-conjugated polyene copolymer (S) has structural units derived from ethylene (A), structural units derived from an α-olefin (B) having 3 to 20 carbon atoms, and structural units derived from a non-conjugated polyene (C) containing two or more partial structures selected from the group consisting of the following general formulas (I) and (II) in total in the molecule, and

Chemical formula

[10] The conveyor belt copolymer composition according to any one of [1] to [9], which further contains the following component (J). Component (J): Organic peroxide crosslinking agent (J)

[11] The ethylene·α-olefin·non-conjugated polyene copolymer (S) has an intrinsic viscosity [η] of 0.1 to 5.0 dL / g and a weight average molecular weight (Mw) of 100,000 to 800,000. The conveyor belt copolymer composition according to any one of [1] to

[10] .

[12] The conveyor belt copolymer composition according to any one of [1] to

[11] , wherein the non-conjugated polyene (C) is 5-vinyl-2-norbornene (VNB).

[13] A heat-resistant conveyor belt made using the conveyor belt copolymer composition according to any one of [1] to

[12] .

Advantages of the Invention

[0007] The rubber composition for conveyor belts of the present invention has high abrasion resistance while also having high heat aging resistance and excellent tear resistance. Therefore, it is useful as a raw material for conveyor belts, and a heat-resistant conveyor belt can be obtained from this composition.

Embodiments for Carrying Out the Invention

[0008] Hereinafter, the present invention will be described in more detail. Here, in this specification, "~" indicating a numerical range means a numerical range including the lower limit value and the upper limit value unless otherwise specified. For example, when expressed as "M~N" (where M and N are numerical values satisfying M < N), it means "M or more and N or less" unless otherwise specified. In addition, in this specification, the "structural unit derived from ethylene" means a structural unit corresponding to ethylene, that is, -CH 2 -CH 2 -. The "structural unit derived from α-olefin" is similarly interpreted to mean a structural unit corresponding to α-olefin, that is, -CH 2 -CRR'-(where R and R' are each independently a hydrogen atom or an alkyl group). Further, the "structural unit derived from non-conjugated polyene" means a structural unit corresponding to non-conjugated polyene, that is, a structural unit having one or more pairs of bonds formed by cleavage of the π bond constituting the double bond among one or more of the double bonds of non-conjugated polyene.

[0009] [Copolymer Composition for Conveyor Belt] The copolymer composition for conveyor belt according to the present invention [hereinafter may be abbreviated as "copolymer composition".] is an ethylene·α-olefin·non-conjugated polyene copolymer (S), an ethylene·α-olefin copolymer (F), an onium salt (K) and contains.

[0010] [Ethylene·α-Olefin·Non-Conjugated Polyene Copolymer (S)] The ethylene·α-olefin·non-conjugated polyene copolymer (S) [hereinafter may be abbreviated as "component (S)" or "copolymer (S)".], which is one of the components contained in the copolymer composition for conveyor belt of the present invention, has a structural unit derived from ethylene (A), a structural unit derived from an α-olefin (B) having 3 to 20 carbon atoms [hereinafter may be abbreviated as "α-olefin (B)"], and a structural unit derived from a non-conjugated polyene (C) [hereinafter may be abbreviated as "non-conjugated polyene (C)".] containing two or more substructures selected from the group consisting of the following general formulas (I) and (II) in total in the molecule.

[0011] [Chemical Formula]

[0012] The component (S) used in the present invention may be a single species or a combination of two or more species.

[0013] In addition to the structural units derived from the above (A), (B), and (C), the component (S) used in the present invention may further have a structural unit derived from a non-conjugated polyene (D) that does not correspond to the above non-conjugated polyene (C) (hereinafter may be abbreviated as "non-conjugated polyene (D)").

[0014] Examples of the α-olefin (B) having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1-hexadecene, 1-eicosene, and the like. Among these, α-olefins having 3 to 8 carbon atoms such as propylene, 1-butene, 1-hexene, and 1-octene are preferable, and propylene is particularly preferable. Such α-olefins are preferable because the raw material cost is relatively low, the resulting copolymer composition for conveyor belts exhibits excellent mechanical properties, and a conveyor belt having rubber elasticity can be obtained. The α-olefin (B) may be a single species or a combination of two or more species.

[0015] The component (S) used in the present invention contains a structural unit derived from at least one α-olefin (B) having 3 to 20 carbon atoms, and may contain structural units derived from two or more α-olefins (B) having 3 to 20 carbon atoms.

[0016] The non-conjugated polyene (C) containing two or more partial structures selected from the group consisting of the above general formulas (I) and (II) in total in the molecule usually contains two or more partial structures selected from the group consisting of the partial structure represented by the above general formula (I) and the partial structure represented by the following general formula (II-1) in total in the molecule. [CH 2 =CH-C *H<] …(II-1) (In the general formula (II-1), C * is a carbon atom constituting a hydrocarbon ring.) Here, the non-conjugated polyene (C) may have two or more partial structures represented by the general formula (I), may have one or more partial structures represented by the general formula (I) and one or more partial structures represented by the general formula (II-1), or may have two or more partial structures represented by the general formula (II-1). Specific examples of such non-conjugated polyene (C) include 5-vinyl-2-norbornene (VNB), norbornadiene, 1,4-hexadiene, dicyclopentadiene, and the like. Among these, since the non-conjugated polyene (C) is preferably VNB because it is easily available, has good reactivity with peroxides during the cross-linking reaction after polymerization, and the heat resistance of the copolymer composition for conveyor belts is easily improved, and more preferably the non-conjugated polyene (C) is VNB. The non-conjugated polyene (C) may be a single species or a combination of two or more species.)

[0017] The component (S) used in the present invention contains a structural unit derived from ethylene (A), a structural unit derived from the α-olefin (B) having 3 to 20 carbon atoms, and a structural unit derived from the non-conjugated polyene (C). Here, in one aspect of the present invention, the component (S) used in the present invention consists only of a structural unit derived from ethylene (A), a structural unit derived from the α-olefin (B) having 3 to 20 carbon atoms, and a structural unit derived from the non-conjugated polyene (C). On the other hand, in another aspect of the present invention, the component (S) used in the present invention, in addition to a structural unit derived from ethylene (A), a structural unit derived from the α-olefin (B) having 3 to 20 carbon atoms, and a structural unit derived from the non-conjugated polyene (C), may further contain a structural unit derived from a non-conjugated polyene (D) that does not correspond to the non-conjugated polyene (C). Specifically, the non-conjugated polyene (D) is a non-conjugated polyene that contains only one partial structure selected from the group consisting of the partial structure represented by the general formula (I) and the partial structure represented by the general formula (II-1) in the molecule. For example, a non-conjugated polyene that contains only one partial structure represented by the general formula (I) in the molecule and does not contain the partial structure represented by the general formula (II-1) can be mentioned.Specific examples of such non-conjugated polyene (D) include 5-ethylidene-2-norbornene (ENB), 5-methylene-2-norbornene, 5-(2-propenyl)-2-norbornene, 5-(3-butenyl)-2-norbornene, 5-(1-methyl-2-propenyl)-2-norbornene, 5-(4-pentenyl)-2-norbornene, 5-(1-methyl-3-butenyl)-2-norbornene, 5-(5-hexenyl)-2-norbornene, 5-(1-methyl-4-pentenyl)-2-norbornene, 5-(2,3-dimethyl-3-butenyl)-2-norbornene, 5-(2-ethyl-3-butenyl)-2-norbornene, 5-(6-heptenyl)-2-norbornene, 5-(3-methyl-5-hexenyl)-2-norbornene, 5-(3,4-dimethyl-4-pentenyl)-2-norbornene, 5-(3-ethyl-4-pentenyl)-2-norbornene, 5-(7-octenyl)-2-norbornene, 5-(2-methyl-6-heptenyl)-2-norbornene, 5-(1,2-dimethyl-5-hexenyl)-2-norbornene, 5-(5-ethyl-5-hexenyl)-2-norbornene, 5-(1,2,3-trimethyl-4-pentenyl)-2-norbornene and the like. Among these, 5-ethylidene-2-norbornene (ENB) is preferred as the non-conjugated polyene (D) because it is easily available, has high reactivity with crosslinking agents and crosslinking accelerators such as organic peroxides and sulfur during the crosslinking reaction after polymerization, is easy to control the crosslinking rate, and good mechanical properties can be easily obtained. The non-conjugated polyene (D) may be used alone or in combination of two or more.

[0018] When the component (S) used in the present invention contains a structural unit derived from the non-conjugated polyene (D), its content ratio is not particularly limited as long as it does not impair the object of the present invention, but usually, it is contained in a mass fraction of more than 0% by mass and 20% by mass or less, preferably more than 0% by mass and 8% by mass or less, more preferably about 0.01% by mass or more and 8% by mass or less (however, the total of the mass fraction of the structural unit derived from (A), the mass fraction of the structural unit derived from (B), the mass fraction of the structural unit derived from (C), and the mass fraction of the structural unit derived from (D) is 100% by mass).

[0019] Component (S) used in the present invention is a copolymer having a structural unit derived from ethylene (A), a structural unit derived from the α-olefin (B) having 3 to 20 carbon atoms, a structural unit derived from the non-conjugated polyene (C), and, if necessary, a structural unit derived from the non-conjugated polyene (D), and satisfies the following requirements (i) to (v).

[0020] [Requirement (i)] The molar ratio of ethylene / α-olefin is 40 / 60 to 99.9 / 0.1.

[0021] [Requirement (ii)] The mass fraction of the structural unit derived from the non-conjugated polyene (C) is 0.07% by mass to 10% by mass.

[0022] [Requirement (iii)] The weight average molecular weight (Mw) of the ethylene·α-olefin·non-conjugated polyene copolymer (S), the mass fraction of the structural unit derived from the non-conjugated polyene (C) ((mass fraction of (C) (% by mass))), and the molecular weight of the non-conjugated polyene (C) ((molecular weight of (C))) satisfy the following formula (1). 4.5 ≦ Mw × (mass fraction of (C)) / 100 / (molecular weight of (C)) ≦ 80 ··· Formula (1)

[0023] [Requirement (iv)] The ratio P (η * (ω=0.1) (Pa·sec) at a frequency ω = 0.1 rad / s and the complex viscosity η * (ω=100) (Pa·sec) at a frequency ω = 100 rad / s, the ratio P(η * (ω=0.1) / η * (ω=100) ) and the intrinsic viscosity [η], and the mass fraction of the structural unit derived from the non-conjugated polyene (C) ((mass fraction of (C))) satisfy the following formula (2). P / ([η] 2.9 ) ≦ (mass fraction of (C)) × 6 ··· Formula (2)

[0024] Requirement (v) The number of long-chain branches per 1000 carbon atoms (LCB 1000C ) and the natural logarithm of the weight-average molecular weight [Ln(Mw)] obtained using 3D-GPC satisfy the following formula (3). LCB 1000C ≤ 1 - 0.07 × Ln(Mw) ··· Formula (3) In the present specification, "α-olefin having 3 to 20 carbon atoms" is also simply referred to as "α-olefin".

[0025] Regarding Requirement (i) Requirement (i) specifies that the molar ratio of ethylene / α-olefin in the component (S) used in the present invention (i.e., the molar ratio of the structural unit derived from ethylene (A) constituting the component (S) and the structural unit derived from α-olefin (B) having 3 to 20 carbon atoms) satisfies 40 / 60 to 99.9 / 0.1, and this molar ratio preferably satisfies 50 / 50 to 90 / 10, more preferably 55 / 45 to 85 / 15, still more preferably 60 / 40 to 80 / 20, and particularly preferably 65 / 35 to 75 / 25. Such a component (S) is preferable because when used as a raw material for a crosslinked molded body, the resulting crosslinked molded body exhibits excellent rubber elasticity and is excellent in mechanical strength and flexibility.

[0026] In addition, the amount of ethylene in the component (S) (the content of the structural unit derived from ethylene (A)) and the amount of α-olefin (the content of the structural unit derived from α-olefin (B)) can be determined by 13 C-NMR.

[0027] Regarding Requirement (ii) Requirement (ii) specifies that the mass fraction of the structural unit derived from the non-conjugated polyene (C) in the component (S) used in the present invention is in the range of 0.07% by mass to 10% by mass in 100% by mass of the ethylene·α-olefin·non-conjugated polyene copolymer (S) (that is, in the total mass fraction of all structural units of 100% by mass). The mass fraction of the structural unit derived from this non-conjugated polyene (C) is preferably 0.1% by mass to 8.0% by mass, more preferably 0.5% by mass to 5.0% by mass, still more preferably 1.0% by mass to 3.0% by mass, and particularly preferably 1.2% by mass to 2.0% by mass.

[0028] When the component (S) used in the present invention satisfies requirement (ii), the component (S) used in the present invention has sufficient hardness and excellent mechanical properties, which is preferable. When crosslinked using a peroxide, it will show a fast crosslinking rate, and the component (S) used in the present invention is suitable for the production of a crosslinked molded body, which is preferable. Incidentally, the amount of the non-conjugated polyene (C) (the content of the structural unit derived from the non-conjugated polyene (C)) in the component (S) 13 can be determined by C-NMR.

[0029] 〔Regarding requirement (iii)〕 Requirement (iii) specifies that in the component (S) used in the present invention, the weight average molecular weight (Mw) of the ethylene·α-olefin·non-conjugated polyene copolymer, the mass fraction of the structural unit derived from the non-conjugated polyene (C) in the copolymer ((C) mass fraction: % by mass), and the molecular weight of the non-conjugated polyene (C) ((C) molecular weight) satisfy the following relational expression (1). 4.5 ≦ Mw × (C) mass fraction / 100 / (C) molecular weight ≦ 80 ··· Formula (1)

[0030] When the component (S) used in the present invention satisfies the requirement (iii), the content of the structural unit derived from the non-conjugated polyene (C) such as VNB is appropriate, showing sufficient crosslinking performance. When a conveyor belt is manufactured using the copolymer composition containing the component (S) used in the present invention, it is preferable because it has excellent crosslinking speed and the conveyor belt after crosslinking exhibits excellent mechanical properties.

[0031] More preferably, the component (S) used in the present invention desirably satisfies the following relational expression (1'). 45 ≦ Mw × mass fraction of (C) / 100 / molecular weight of (C) ≦ 80 ··· Formula (1') Note that the weight average molecular weight (Mw) of the ethylene·α-olefin·non-conjugated polyene copolymer (S) means the value measured by 3D-GPC.

[0032] When the component (S) used in the present invention satisfies the formula (1) or (1') for "Mw × mass fraction of (C) / 100 / molecular weight of (C)", the degree of crosslinking becomes appropriate, and by using this, a molded article excellent in mechanical properties and heat aging resistance can be manufactured with good balance. When "Mw × mass fraction of (C) / 100 / molecular weight of (C)" is too small, the crosslinkability may be insufficient and the crosslinking speed may become slow. When it is too large, excessive crosslinking may occur and the mechanical properties may deteriorate.

[0033] 〔Regarding Requirement (iv)〕 Requirement (iv) is the ratio P (η * (ω=0.1) (Pa·sec) at a frequency ω = 0.1 rad / s and the complex viscosity η * (ω=100) (Pa·sec) at a frequency ω = 100 rad / s obtained by linear viscoelastic measurement (190°C) of the component (S) used in the present invention using a rheometer * (ω=0.1) / η * (ω=100)and the limiting viscosity [η] and the mass fraction of the structural unit derived from the non-conjugated polyene (C) ((mass fraction of (C): mass %) satisfy the following formula (2). P / ([η] 2.9 ) ≤ mass fraction of (C) × 6 ··· Formula (2)

[0034] Here, the complex viscosity η * (ω=0.1) at a frequency ω = 0.1 rad / s and the complex viscosity η * (ω=100) at a frequency ω = 100 rad / s, and the ratio P(η * (ω=0.1) / η * (ω=100) ) represents the frequency dependence of the viscosity, and P / ([η] 2.9 ), which corresponds to the left side of Formula (2), shows a tendency to have a high value when there are many long-chain branches, although it is affected by short-chain branches and molecular weight. Generally, in an ethylene·α-olefin·non-conjugated polyene copolymer, the more the structural unit derived from the non-conjugated polyene is contained, the more likely it is to contain many long-chain branches. However, the component (S) used in the present invention is considered to be able to satisfy the above Formula (2) because it has fewer long-chain branches than a conventionally known ethylene·α-olefin·non-conjugated polyene copolymer. In the present invention, the P value was determined by measuring with a viscoelasticity measuring device Ares (manufactured by Rheometric Scientific) at 190 °C, a strain of 1.0%, and varying the frequency, and calculating the ratio (η * ratio) from the complex viscosity at 0.1 rad / s and the complex viscosity at 100 rad / s.

[0035] The component (S) used in the present invention preferably satisfies the following formula (2'). P / ([η] 2.9 ) ≤ mass fraction of (C) × 5.7 ··· Formula (2') The limiting viscosity [η] means the value measured in decalin at 135 °C.

[0036] [Regarding requirement (v)] Requirement (v) specifies that the number of long-chain branches per 1000 carbon atoms (LCB 1000C ) of component (S) obtained using 3D-GPC and the natural logarithm of the weight-average molecular weight [Ln(Mw)] satisfy the following formula (3). LCB 1000C ≦1 - 0.07 × Ln(Mw) ··· Formula (3)

[0037] The upper limit value of the long-chain branch content per carbon atom of component (S) is specified by the above formula (3). Such a component (S) has a low proportion of long-chain branches contained therein, is excellent in curing characteristics when crosslinked using a peroxide, and is preferable because the conveyor belt obtained using the same has excellent heat aging resistance.

[0038] Component (S) used in the present invention preferably satisfies the following formula (3'). LCB 1000C ≦1 - 0.071 × Ln(Mw) ··· Formula (3')[[]END] Here, Mw and the number of long-chain branches per 1000 carbon atoms (LCB 1000C ) can be determined by a structural analysis method using 3D-GPC. In this specification, specifically, it was determined as follows.

[0039] Using a 3D-high temperature GPC device (PL-GPC220 type, manufactured by Polymer Laboratories), the absolute molecular weight distribution of the ethylene·α-olefin·non-conjugated polyene copolymer (S) was determined, and at the same time, the intrinsic viscosity was determined using a viscometer. The main measurement conditions are as follows. Detector: Differential refractometer built into the GPC device Two-angle light scattering photometer PD2040 type (manufactured by Precison Detectors) Bridge type viscometer PL-BV400 type (manufactured by Polymer Laboratories) Column: TSKgel GMH HR -H(S)HT × 2 pieces + TSKgel GMH HR -M(S) × 1 piece (All have an inner diameter of 7.8 mmφ per piece × length of 300 mm) Temperature: 140 °C Mobile phase: 1,2,4-trichlorobenzene (containing 0.025% BHT) Injection volume: 0.5 mL Sample concentration: ca 1.5 mg / mL Sample filtration: Filtered through a sintered filter with a pore size of 1.0 μm The dn / dc value (the differential value of the refractive index n with respect to the concentration c) required for the determination of the absolute molecular weight was determined for each sample from the dn / dc value of standard polystyrene (molecular weight 190,000) of 0.053 and the response intensity of the differential refractometer per unit injection mass.

[0040] The long-chain branching parameter g'i for each eluted component was calculated from equation (v-1) based on the relationship between the intrinsic viscosity measured in decalin at 135 °C and the absolute molecular weight obtained from the light scattering photometer.

[0041] [Number]

[0042] Here, [η] = KM v ; The relational expression of v = 0.725 was applied. This equation is called the Mark-Houwink-Sakurada equation, where K is the viscosity coefficient, M is the absolute molecular weight obtained from 3D-GPC, and v represents the form of the polymer chain at the measurement temperature in the measurement solvent (i.e., for example, the way the molecule spreads such as the shape of the molecule and the degree of bending). Also, each average value of g' was calculated from the following equations (v-2), (v-3), and (v-4). The Trendline assuming only short-chain branches was determined for each sample.

[0043] [Number]

[0044] Furthermore, using the weight-average long-chain branching parameter: g'w represented by the above equation (v-3), the number of branch points per molecular chain BrNo, and the number of long-chain branches per 1000 carbons LCB 1000C, the branching degree λ per unit molecular weight was calculated. The BrNo calculation uses the Zimm-Stockmayer equation (v-5), and the calculation of LCB 1000C and λ uses the following equations (v-6) and (v-7). g is the long-chain branching parameter obtained from the radius of gyration Rg, and the following simple correlation is made with g' obtained from the intrinsic viscosity. g = g' (1 / ε) Here, ε (structure factor) = 0.5 to 1.5 (usually 0.75) Various values of ε in the above equation have been proposed according to the molecular shape. Here, the calculation was performed assuming ε = 1 (i.e., g' = g).

[0045]

Equation

[0046] λ = BrNo / M ··· (v-6) LCB 1000C = λ × 14000 ··· (v-7) *In equation (v-7), 14000 represents the molecular weight of 1000 methylene (CH 2 ) units.

[0047] The intrinsic viscosity [η] of the component (S) used in the present invention is preferably 0.1 to 5.0 dL / g, more preferably 0.5 to 4.0 dL / g, still more preferably 1.0 to 3.8 dL / g, and particularly preferably 2.0 to 3.5 dL / g. Here, the intrinsic viscosity [η] is the same as that described above in the above requirement (iv), that is, the value measured in decalin at 135°C.

[0048] Also, the component (S) used in the present invention desirably has a weight average molecular weight (Mw) of preferably 100,000 to 800,000, more preferably 200,000 to 700,000, still more preferably 250,000 to 650,000, and particularly preferably 300,000 to 600,000.

[0049] Component (S) used in the present invention preferably satisfies both the above-mentioned intrinsic viscosity [η] and weight-average molecular weight (Mw). In component (S) used in the present invention, the non-conjugated polyene (C) preferably contains VNB, and more preferably is VNB. That is, in the above-mentioned formula (1), formula (2), and formula (4) described later, etc., the "mass fraction of (C)" is preferably the "mass fraction of VNB" (mass%).

[0050] As described above, component (S) used in the present invention, in addition to the structural units derived from the above (A), (B), and (C), further contains the structural units derived from the above non-conjugated polyene (D) in a mass fraction of 0 mass% to 20 mass% (however, the total of the mass fraction of the structural units derived from (A), the mass fraction of the structural units derived from (B), the mass fraction of the structural units derived from (C), and the mass fraction of the structural units derived from (D) is 100 mass%). In this case, it is preferable to satisfy requirement (vi) described later in "Other Requirements" below.

[0051] 〔Regarding Other Requirements〕 Component (S) used in the present invention preferably satisfies at least one of the following requirement (vi) and the following requirement (vii) in addition to the above requirements (i) to (v), and more preferably satisfies both the following requirement (vi) and the following requirement (vii).

[0052] Requirement (vi) The weight-average molecular weight (Mw) of the ethylene·α-olefin·non-conjugated polyene copolymer, the mass fraction of the structural units derived from the non-conjugated polyene (C) ((mass fraction of (C)) (mass%)), the mass fraction of the structural units derived from the non-conjugated polyene (D) ((mass fraction of (D)) (mass%)), the molecular weight of the non-conjugated polyene (C) ((molecular weight of (C))), and the molecular weight of the non-conjugated polyene (D) ((molecular weight of (D))) satisfy the following formula (4).

[0053] 4.5 ≤ Mw × {((mass fraction of (C)) / 100 / molecular weight of (C)) + ((mass fraction of (D)) / 100 / molecular weight of (D))} ≤ 85 ··· Formula (4) In Formula (4), the content of non-conjugated diene ((total of (C) and (D))) in one molecule of the copolymer is specified.

[0054] When the ethylene·α-olefin·non-conjugated polyene copolymer containing the structural unit derived from the above (D) satisfies Formula (4), it is preferable because the conveyor belt obtained from the ethylene·α-olefin·non-conjugated polyene copolymer exhibits excellent mechanical properties and heat aging resistance.

[0055] If requirement (vi) is not satisfied and "Mw × {((mass fraction of (C)) / 100 / molecular weight of (C)) + ((mass fraction of (D)) / 100 / molecular weight of (D))}" in Formula (4) is too small, that is, if the content of non-conjugated diene is too small, sufficient cross-linking may not occur and appropriate mechanical properties may not be obtained. If it is too large, cross-linking may be excessive, mechanical properties may deteriorate, and heat aging resistance may also deteriorate.

[0056] Requirement (vii) Component (S) used in the present invention is not particularly limited, but the complex viscosity η * (ω=0.01) (Pa·sec) at a frequency ω = 0.01 rad / s and the complex viscosity η * (ω=10) (Pa·sec) at a frequency ω = 10 rad / s, and the apparent iodine value derived from non-conjugated polyene (C) preferably satisfy the following formula (5).

[0057] Log{η * (ω=0.01)} / Log{η * (ω=10)} ≤ 0.0753 × {apparent iodine value derived from non-conjugated polyene (C)} + 1.42 ··· Formula (5) Here, the complex viscosity η * (ω=0.01) and the complex viscosity η *(ω=10) is the complex viscosity η in requirement (iv) except for the measurement frequency * (ω=0.1) and the complex viscosity η * (ω=100) are determined in the same manner.

[0058] Also, the apparent iodine value derived from the non-conjugated polyene (C) is determined by the following formula. Apparent iodine value derived from (C) = mass fraction of (C) × 253.81 / molecular weight of (C) In the above formula (5), the left side represents the shear rate dependence that is an index of the long-chain branching amount, and the right side represents an index of the content of the non-conjugated polyene (C) that has not been consumed as long-chain branches during polymerization. When requirement (vii) is satisfied and the above formula (5) is satisfied, it is preferable because the degree of long-chain branching is not too high. On the other hand, when the above formula (5) is not satisfied, it can be seen that the proportion of the copolymerized non-conjugated polyene (C) consumed for the formation of long-chain branches is large.

[0059] Others In addition to the above requirement (vi) and / or the above requirement (vii), or instead of the above requirement (vi) and / or the above requirement (vii), it is also preferable that the component (S) used in the present invention satisfies the following requirements. The component (S) used in the present invention preferably contains a sufficient amount of structural units derived from the non-conjugated polyene (C), and the mass fraction of the structural units derived from the non-conjugated polyene (C) in the copolymer ((mass fraction of (C) (mass%))) and the weight average molecular weight (Mw) of the copolymer preferably satisfy the following formula (6). 6 - 0.45 × Ln(Mw) ≤ mass fraction of (C) ≤ 10 ··· formula (6)

[0060] Also, the component (S) used in the present invention has the number (n C ) of structural units derived from the non-conjugated polyene (C) per weight average molecular weight (Mw) is preferably 6 or more, more preferably 6 or more and 80 or less, still more preferably 7 or more and 79 or less, and even more preferably 10 or more and 78 or less.

[0061] Component (S) used in the present invention contains a sufficient amount of structural units derived from non-conjugated polyene (C) such as VNB, has a low long-chain branching content, is excellent in curing characteristics when crosslinked using peroxides, has good moldability, is excellent in the balance of physical properties such as mechanical properties, and is particularly excellent in heat aging resistance.

[0062] Furthermore, in component (S) used in the present invention, the number (n D ) of structural units derived from non-conjugated polyene (D) per weight average molecular weight (Mw) is preferably 29 or less, more preferably 10 or less, and even more preferably less than 1.

[0063] Component (S) used in the present invention is preferably such that the content of structural units derived from non-conjugated polyene (D) such as ENB is suppressed within a range not impairing the object of the present invention, is less likely to cause post-crosslinking, and has sufficient heat aging resistance.

[0064] Here, the number (n C ) of structural units derived from non-conjugated polyene (C) or the number (n D ) of structural units derived from non-conjugated polyene (D) per weight average molecular weight (Mw) of component (S) can be determined by the following formula from the molecular weight of non-conjugated polyene (C) or (D), the mass fraction of the structural units derived from non-conjugated polyene (C) or (D) in the copolymer ((C) or (D) mass fraction (mass%)), and the weight average molecular weight (Mw) of the copolymer. (n C ) = (Mw) × {(mass fraction of (C) / 100)} / molecular weight of non-conjugated polyene (C) (n D ) = (Mw) × {(mass fraction of (D) / 100)} / molecular weight of non-conjugated polyene (D)

[0065] In the ethylene·α-olefin·non-conjugated polyene copolymer (S) used in the present invention, the number (n C ) and (nD ) all meet the above ranges, the ethylene-α-olefin-non-conjugated polyene copolymer has a low long-chain branch content, and when crosslinked using a peroxide, it has excellent curing characteristics, good moldability, excellent physical property balance such as mechanical properties, and is less likely to cause post-crosslinking, especially excellent in heat aging resistance, which is preferable.

[0066] <Production of Ethylene-α-Olefin-Non-Conjugated Polyene Copolymer (S)> The ethylene-α-olefin-non-conjugated polyene copolymer (S) used in the present invention is a copolymer obtained by copolymerizing a monomer composed of ethylene (A), the above α-olefin (B) having 3 to 20 carbon atoms, the above non-conjugated polyene (C), and, if necessary, the above non-conjugated polyene (D).

[0067] The component (S) used in the present invention may be prepared by any production method as long as the above requirements (i) to (v) are satisfied, but it is preferably obtained by copolymerizing a monomer (that is, ethylene (A), the above α-olefin (B), the above non-conjugated polyene (C), and the optional above non-conjugated polyene (D)) in the presence of a metallocene compound, and more preferably obtained by copolymerizing a monomer in the presence of a catalyst system containing a metallocene compound.

[0068] As a specific production method of the above component (S) used in the present invention, for example, it can be produced by adopting the production method using a metallocene catalyst described in JP-A No. 2018-119096 and WO 2015 / 122495 pamphlet. At that time, ethylene (A), α-olefin (B), non-conjugated polyene (C), and the optional above non-conjugated polyene (D) may each be derived from biomass. Here, the monomer derived from biomass contains 14 C isotope at a ratio of about 10 -12 ~10 -14 while the corresponding monomer derived from fossil fuel is 14 due to the radioactive decay of 14It is known that it does not contain C. Therefore, the biomass-derived monomer and the fossil fuel-derived monomer can be distinguished by whether or not they contain 14 C isotope. It is preferable from the viewpoint of reducing the environmental load that the component (S) contains a structural unit derived from a biomass-derived monomer. 14 Moreover, ethylene (A), α-olefin (B), non-conjugated polyene (C), and optional non-conjugated polyene (D) may each be derived from chemical recycling. Here, "derived from chemical recycling" means that it can be obtained by depolymerizing, thermally decomposing, etc. a polymer such as waste plastic, or once converted into an intermediate by depolymerizing, thermally decomposing, etc. a polymer such as waste plastic, and obtained by manufacturing using this intermediate as a raw material. Monomers derived from chemical recycling can be obtained by known methods. It is preferable from the viewpoint of reducing the environmental load (mainly reducing waste) that the component (S) contains a structural unit derived from a monomer derived from chemical recycling.

[0069] <Ethylene·α-olefin copolymer (F)> The ethylene·α-olefin copolymer (F) [hereinafter, may be abbreviated as "component (F)" or "copolymer (F)"] which is one of the components contained in the copolymer composition for conveyor belt of the present invention is a copolymer of ethylene (A) and an α-olefin (B') having 3 to 20 carbon atoms. That is, the ethylene·α-olefin copolymer (F) has a structural unit derived from ethylene (A) and a structural unit derived from an α-olefin (B') having 3 to 20 carbon atoms [hereinafter, may be abbreviated as "α-olefin (B')"].

[0070] The component (F) used in the present invention may be a single type or a combination of two or more types.

[0071] As the α-olefin (B'), an α-olefin having 3 to 12 carbon atoms, more preferably 3 to 8 carbon atoms, is desirable from the viewpoint of obtaining a conveyor belt having excellent mechanical strength. Specific examples of such α-olefins (B') include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 9-methyl-1-decene, 11-methyl-1-dodecene, 12-ethyl-1-tetradecene, and the like. Among them, propylene, 1-butene, 1-hexene, 1-octene, etc. are preferably used, and among these, propylene and 1-butene are more preferred, and 1-butene is even more preferred. These α-olefins may be used alone or in combination of two or more.

[0072] Here, in one of the exemplary embodiments of the present invention, the α-olefin (B') is an α-olefin (B'1) having 4 to 20 carbon atoms [hereinafter, may be abbreviated as "α-olefin (B'1)"]. In this embodiment, the α-olefin (B'1) is preferably an α-olefin having 4 to 12 carbon atoms, more preferably an α-olefin having 4 to 8 carbon atoms. Specific examples of the α-olefin (B'1) include those other than propylene among the specific examples of the α-olefin (B') shown above. Among these, 1-butene, 1-hexene, 1-octene, etc. are preferred, and 1-butene is more preferred. Further, the α-olefin (B') may be an α-olefin (B'2) having 3 carbon atoms [hereinafter, may be abbreviated as "α-olefin (B'2)"], that is, propylene. In a typical embodiment of the present invention, component (F) includes an ethylene-α-olefin copolymer (F1) having a structural unit derived from ethylene (A) and a structural unit derived from an α-olefin (B'1) having 4 to 20 carbon atoms [hereinafter, may be abbreviated as "component (F1)", "ethylene-α-olefin copolymer (F1)", or "copolymer (F1)"]. Here, when the copolymer composition for a conveyor belt of the present invention contains component (F) alone, the component (F) is preferably component (F1). In one of the preferred and exemplary embodiments of the present invention, the component (F1) is an ethylene-1-butene copolymer. On the other hand, when the copolymer composition for a conveyor belt of the present invention contains two or more components (F), in addition to the component (F1), the component (F) may further include an ethylene-α-olefin copolymer (F2) having a structural unit derived from ethylene (A) and a structural unit derived from an α-olefin (B'2) having 3 carbon atoms [hereinafter, may be abbreviated as "component (F2)", "ethylene-α-olefin copolymer (F2)", or "copolymer (F2)"], that is, an ethylene-propylene copolymer. That is, the copolymer composition for a conveyor belt of the present invention may contain two or more of the above-mentioned components (F1), or may contain the component (F1) and the component (F2). Here, in the copolymer composition for a conveyor belt of the present invention, the component (F2) may be included in a form that partially replaces the above-mentioned component (S). When the copolymer composition for a conveyor belt of the present invention contains the component (F1) as the component (F), particularly when it contains the component (F1) and the component (F2) as the component (F), it tends to have excellent tear resistance.

[0073] In the component (F) used in the present invention, the content of the structural unit derived from ethylene is preferably 50 to 85 mol% (however, the total of the structural unit derived from ethylene and the structural unit derived from an α-olefin having 3 to 20 carbon atoms is 100 mol%). Here, it is more preferable that the content is 50 to 83 mol%. When the content of the structural unit derived from ethylene in the component (F) is within the above range, a copolymer composition for a conveyor belt excellent in compatibility with the component (S) can be obtained. The same applies to the content of the structural unit derived from ethylene in the component (F1) (in this case, the total of the structural unit derived from ethylene and the structural unit derived from an α-olefin having 4 to 20 carbon atoms is 100 mol%), and the content of the structural unit derived from ethylene in the component (F2) (in this case, the total of the structural unit derived from ethylene and the structural unit derived from propylene is 100 mol%).

[0074] The component (F) used in the present invention preferably satisfies the following requirement (f-i), and more preferably satisfies one or more of the following requirements (f-ii) to (f-iv) in addition to the following requirement (f-i) (for example, it is preferable to satisfy the following requirement (f-i) and the following requirement (f-ii)). It is even more preferable to satisfy two or more of the following requirements (f-ii) to (f-iv) in addition to the following requirement (f-i), and it is particularly preferable to satisfy all of the following requirements (f-i) to (f-iv). Further, the component (F) may satisfy the following requirement (f-v) in addition to the following requirement (f-i). In this case, it is preferable to satisfy the following requirement (f-i), one or more of the following requirements (f-ii) to (f-iv), and the following requirement (f-v), and it is more preferable to satisfy the following requirement (f-i), two or more of the following requirements (f-ii) to (f-iv), and the following requirement (f-v). The component (F) may satisfy all of the following requirements (f-i) to (f-v). The same applies to the component (F1) and the component (F2) which are components corresponding to the component (F). In one preferred and exemplary embodiment of the present invention, the component (F1) satisfies the following requirements (f-i) to (f-iii) and the following requirement (f-v), and the component (F2) satisfies the following requirements (f-i) to (f-ii) and the following requirement (f-v). In this embodiment, the component (F1) may further satisfy the following requirement (f-iv), and the component (F2) may further satisfy the following requirement (f-iii) and / or the following requirement (f-iv).

[0075] (f-i) Melting point The melting point of the component (F) used in the present invention is preferably 150°C or lower, more preferably 120°C or lower, still more preferably 100°C or lower, even more preferably 90°C or lower, particularly preferably 70°C or lower, and especially preferably 60°C or lower. When the melting point of the component (F) is within the above range, the unmelted component (F) does not remain even at a low kneading temperature. In particular, a conveyor belt with a small molding shrinkage rate and excellent wear resistance can be obtained. Here, among the components corresponding to the component (F), the melting point of the component (F1) is preferably 100°C or lower, more preferably 90°C or lower, still more preferably 70°C or lower, and particularly preferably 60°C or lower. On the other hand, among the components corresponding to the component (F), the melting point of the component (F2) is preferably 150°C or lower, more preferably 120°C or lower. Note that the melting point of the component (F2) may exceed 100°C. The melting point of the component (F) used in the present invention can be measured by the method described in JIS K 7121.

[0076] (f-ii) Density The density of the component (F) used in the present invention is preferably 840 to 920 kg / m 3 and more preferably 850 to 910 kg / m 3 and still more preferably 855 to 900 kg / m 3 and particularly preferably 860 to 890 kg / m 3When the density of the component (F) is within the above range, a conveyor belt with a small molding shrinkage rate and excellent strength characteristics and wear resistance can be obtained. The same applies to the density of the component (F1) and the density of the component (F2). The density of the component (F) used in the present invention can be measured by the method described in ASTM D1505.

[0077] (f-iii) MFR The MFR of the component (F) used in the present invention at 190 °C and a load of 2.16 kgf is preferably 0.1 to 50 g / 10 min, more preferably 0.5 to 30.0 g / 10 min, still more preferably 1.0 to 10 g / 10 min, and particularly preferably 1.1 to 5.0 g / 10 min. Here, in one of the preferred and exemplary embodiments of the present invention, the MFR is 2.0 to 5.0 g / 10 min. However, this does not prevent the MFR from being less than 2.0 g / 10 min. When the MFR of the component (F) is within the above range, a copolymer composition for a conveyor belt with a small molding shrinkage rate and excellent processability can be obtained. The same applies to the MFR of the component (F1) and the MFR of the component (F2). The MFR of the component (F) used in the present invention can be measured by the method described in ASTM D1238.

[0078] (f-iv) Mw / Mn The component (F) used in the present invention preferably has a ratio Mw / Mn of the weight average molecular weight Mw to the number average molecular weight Mn, determined by GPC analysis, in the range of 1.5 to 10.0. The same applies to the Mw / Mn of the component (F1) and the Mw / Mn of the component (F2).

[0079] Component (F) used in the present invention preferably has a weight average molecular weight (Mw) determined by gel permeation chromatography (GPC) in the range of 10,000 to 500,000, more preferably 20,000 to 300,000, and still more preferably 20,000 to 200,000. The same applies to the Mw of the component (F1) and the Mw of the component (F2).

[0080] Also, the component (F) used in the present invention is preferably solid at room temperature to about 100 °C, preferably at a temperature around 90 °C. When the weight average molecular weight of the component (F) used in the present invention is within the above range, a conveyor belt with a small molding shrinkage rate and excellent abrasion resistance can be obtained. Also, since there are few low molecular weight components, volatilization and protrusion of the low molecular weight components are less likely to occur in the obtained conveyor belt, which is preferable.

[0081] The Mw, Mn, and Mw / Mn of the component (F) used in the present invention can be measured by the same method as the method for measuring the molecular weight of the ethylene·α-olefin·non-conjugated polyene copolymer (S) described in the following examples.

[0082] The component (F) used in the present invention preferably satisfies the following requirement (f-v). (f-v) Mooney viscosity ML (1+4) 100 °C The Mooney viscosity ML of the component (F) used in the present invention at 100 °C (1+4) at 100 °C is preferably in the range of 1 to 100, more preferably 5 to 80, still more preferably 10 to 60, and particularly preferably 12 to 50. The Mooney viscosity ML of the component (F) (1+4) at 100 °C being within the above range enables the obtainment of a copolymer composition for a conveyor belt with a small molding shrinkage rate and excellent processability. The Mooney viscosity ML of the component (F1) (1+4) at 100 °C and the Mooney viscosity ML of the component (F2) (1+4) at 100 °C are the same. Mooney viscosity ML (1+4)100 °C can be measured in accordance with JIS K 6300-1 (2013).

[0083] Component (F) used in the present invention can be produced, for example, by copolymerizing ethylene and an α-olefin by a conventionally known method using a vanadium-based catalyst, a Ziegler-Natta catalyst, or a metallocene catalyst. From the viewpoint of easily obtaining a copolymer that satisfies the above physical properties, a method of synthesis using a metallocene catalyst is preferred. Specifically, a catalyst containing a metallocene compound and an aluminum-containing compound described in International Publication No. 2008 / 152935, or a catalyst composed of a metallocene compound and an organoaluminum oxy compound or an ionizing ionic compound described in JP-A-9-40586 is more preferred for synthesis. In addition, when producing component (F) used in the present invention, ethylene and α-olefin may each be derived from biomass. Further, when producing component (F) used in the present invention, ethylene and α-olefin may each be derived from chemical recycling.

[0084] <onium salt (K)> The copolymer composition for a conveyor belt of the present invention includes, in addition to the above components (S) and (F), an onium salt (K) [hereinafter, may be abbreviated as "component (K)"]. By including the onium salt (K), the copolymer composition for a conveyor belt of the present invention has high heat aging resistance while having high wear resistance when used for a conveyor belt. Examples of the onium salt (K) include quaternary ammonium salts, quaternary phosphonium salts, oxonium salts, sulfonium salts, cyclic amines, monofunctional amine compounds, etc. Among these, quaternary ammonium salts and quaternary phosphonium salts are preferred.

[0085] The onium salt (K) may be used alone or in combination of two or more. The quaternary ammonium salt is not particularly limited. For example, it includes dialkyl (C14-18) dimethylammonium chloride, 1,8-diazabicyclo[5,4,0]-7-undecenium salt, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium iodide, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-methyl-1,8-diazabicyclo[5,4,0]-7-undecenium methyl sulfate, 8-ethyl-1,8-diazabicyclo[5,4,0]-7-undecenium bromide, 8-propyl-1,8-diazabicyclo[5,4,0]-7-undecenium bromide, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-dodecyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-eicosyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-tetracosyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride (hereinafter referred to as DBU-B), 8-benzyl-1,8-diazabicyclo[5,4,0]-7-undecenium hydroxide, 8-phenethyl-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, 8-(3-phenylpropyl)-1,8-diazabicyclo[5,4,0]-7-undecenium chloride, and the like. Among these, dialkyl (C14-18) dimethylammonium chloride is preferred.

[0086] The quaternary phosphonium salt is not particularly limited. For example, tetrabutylphosphonium chloride, benzyltriphenylphosphonium chloride (hereinafter referred to as BTPPC), benzyltrimethylphosphonium chloride, benzyltributylphosphonium chloride, tributylallylphosphonium chloride, tributyl-2-methoxypropylphosphonium chloride, benzylphenyl(dimethylamino)phosphonium chloride, etc. can be mentioned. Among these, benzyltriphenylphosphonium chloride (BTPPC) is preferable from the viewpoints of vulcanization properties and physical properties of the vulcanizate.

[0087] A solid solution of the quaternary ammonium salt, quaternary phosphonium salt and bisphenol AF, or a compound disclosed in JP-A-11-147891 can also be used. Examples of the amine compound include hexamethylenediamine carbamate, N,N'-dicinnylidene-1,6-hexamethylenediamine, 4,4'-bis(aminocyclohexyl)methane carbamate, etc. Among these, N,N'-dicinnylidene-1,6-hexamethylenediamine is preferable.

[0088] As the onium salt (K), a commercially available product may be used. For example, "Lipocard 2HT Flake" (manufactured by Lion Specialty Chemicals Co., Ltd., dialkyl (C14-18) dimethylammonium chloride, also referred to as "Lipocard 2HTF" in the present invention) can be used.

[0089] <Carbon black (G)> In addition to the above components (S), (F) and (K), the conveyor belt copolymer composition of the present invention may further contain carbon black (G) [hereinafter may be abbreviated as "component (G)"]. Carbon black (G) is a kind of known rubber reinforcing agent that can be compounded into a general rubber composition and is usually an inorganic substance called carbon black. Carbon black (G) may be a single type or a combination of two or more types.

[0090] Specific examples of the carbon black (G) that can be used in the present invention include Asahi #55G, Asahi #60G, Asahi #60UG1, Asahi #70 (above, manufactured by Asahi Carbon Co., Ltd.), carbon blacks such as VULCAN 3D, STERLING (SO, V, VH, 142, etc.) (above, manufactured by Cabot Corporation), and carbon blacks such as Seast (V, SO, 116, 3, 6, 9, SP, TA, etc.) (manufactured by Tokai Carbon Co., Ltd.), and those obtained by surface-treating these carbon blacks with a silane coupling agent or the like.

[0091] <Antioxidant (H)> The copolymer composition for a conveyor belt of the present invention may further contain an antioxidant (H) [hereinafter, may be abbreviated as "component (H)" in some cases]. The antioxidant (H) may be a conventionally known antioxidant, and examples of such antioxidants include amine-based antioxidants, phenol-based antioxidants, sulfur-based antioxidants, and the like.

[0092] Furthermore, examples of the antioxidant (H) include aromatic secondary amine-based antioxidants such as phenylbutylamine and N,N-di-2-naphthyl-p-phenylenediamine; phenol-based antioxidants such as dibutylhydroxytoluene and tetrakis[methylene(3,5-di-t-butyl-4-hydroxy)hydrocinnamate]methane (trade name: Irganox 1010, manufactured by BASF); thioether-based antioxidants such as bis[2-methyl-4-(3-n-alkylthiopropionyloxy)-5-t-butylphenyl]sulfide; dithiocarbamate-based antioxidants such as nickel dibutyldithiocarbamate; sulfur-based antioxidants such as 2-mercaptobenzoyl imidazole (trade name: Sandant MB, manufactured by Sanshin Chemical Industry Co., Ltd.), 2-mercaptobenzimidazole, zinc salt of 2-mercaptobenzimidazole, dilauryl thiodipropionate, and distearyl thiodipropionate. These antioxidants (H) may be used alone or in combination of two or more.

[0093] <Plasticizer (R)> The copolymer composition for a conveyor belt of the present invention may further contain a plasticizer (R) [hereinafter, may be abbreviated as "component (R)"] according to its use. Specifically, the plasticizer (R) may be a known plasticizer generally used as a softening agent in the field of rubber.

[0094] Specific examples of such plasticizers (R) include petroleum-based softening agents such as process oil, lubricating oil, paraffin oil, liquid paraffin, petroleum asphalt, and petrolatum; coal tar-based softening agents such as coal tar and coal tar pitch; fatty oil-based softening agents such as castor oil, linseed oil, rapeseed oil, soybean oil, and coconut oil; waxes such as beeswax, carnauba wax, and lanolin; fatty acids or their salts such as ricinoleic acid, palmitic acid, stearic acid, barium stearate, calcium stearate, and zinc laurate; naphthenic acid, pine oil, and rosin or its derivatives; synthetic polymer substances such as terpene resin, petroleum resin, atactic polypropylene, and coumarone-indene resin; ester-based softening agents such as dioctyl phthalate, dioctyl adipate, and dioctyl sebacate; and others such as microcrystalline wax, liquid polybutadiene, modified liquid polybutadiene, liquid thiocol, hydrocarbon-based synthetic lubricating oil, tall oil, and factice. Among them, petroleum-based softening agents and hydrocarbon-based synthetic lubricating oils are preferred, and hydrocarbon-based synthetic lubricating oils are more preferred. An example of the hydrocarbon-based synthetic lubricating oil is ethylene·α-olefin co-oligomer. These plasticizers (R) may be used alone or in combination of two or more.

[0095] <Organic peroxide-based crosslinking agent (J)> The organic peroxide crosslinking agent (J) [hereinafter may be abbreviated as "component (J)"] which is one of the components that may be contained in the copolymer composition for conveyor belts of the present invention is a kind of crosslinking agent. Specifically, dicumyl peroxide (DCP), di-tert-butyl peroxide, 2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexyne-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate, benzoyl peroxide, p-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, tert-butyl peroxybenzoate, ert-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tert-butyl cumyl peroxide, etc. may be mentioned.

[0096] Among these, organic peroxide crosslinking agents such as dicumyl peroxide (DCP), 2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexane, 2,5-dimethyl-2,5-di-(tert-butylperoxy)hexyne-3, 1,3-bis(tert-butylperoxyisopropyl)benzene, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl-4,4-bis(tert-butylperoxy)valerate are preferred.

[0097] <Copolymer composition for conveyor belt> The copolymer composition for conveyor belts of the present invention contains the above components (S), (F), and (K), and may further contain the above components (G), (H), and / or (R) according to the application. That is, the copolymer composition for conveyor belts of the present invention may further contain any one or more selected from the group consisting of the above components (G), (H), and (R) in addition to the above components (S), (F), and (K). For example, it may further contain the above components (G), (H), and (R). The copolymer composition for conveyor belts of the present invention preferably further contains the above component (J).

[0098] By containing the above components, the copolymer composition for conveyor belts of the present invention has excellent processability, and the conveyor belt obtained from the copolymer composition for conveyor belts is excellent in mechanical properties, heat aging resistance, wear resistance, and oil bleed resistance.

[0099] In the copolymer composition for conveyor belts of the present invention, with the total amount of the above component (S) and the above component (F) being 100 parts by mass, the component (S) is preferably more than 0 parts by mass and 70 parts by mass or less, more preferably 10 parts by mass or more and 60 parts by mass or less, and the component (F) is preferably 30 parts by mass or more and less than 100 parts by mass, more preferably 40 parts by mass or more and 90 parts by mass or less. Here, when the copolymer composition for conveyor belts of the present invention contains two or more kinds of the component (S), the total amount of the two or more kinds of the component (S) is taken as the amount of the component (S). Also, when the copolymer composition for conveyor belts of the present invention contains two or more kinds of the component (F), the total amount of the two or more kinds of the component (F) is taken as the amount of the component (F). Here, when the copolymer composition for conveyor belts of the present invention contains the above component (F2) in addition to the above component (F1), for example, the total of the amount of the above component (S) and the amount of the above component (F2) may be in the range of 30 parts by mass or more and 50 parts by mass or less, and the amount of the above component (F1) may be in the range of 50 parts by mass or more and 70 parts by mass or less. And the copolymer composition for the conveyor belt contains the component (K) in the range of 0.2 to 80 parts by mass, preferably 0.5 to 50 parts by mass, more preferably 1.0 to 30 parts by mass, still more preferably 2.0 to 20 parts by mass, and particularly preferably 3.0 to 12 parts by mass, per 100 parts by mass of the total amount of the component (S) and the component (F). When the content of the component (K) is within the above range, it tends to be excellent in abrasion resistance and tear resistance and is suitable.

[0100] When the copolymer composition for the conveyor belt contains the optional components (G), (H) and / or (R), the copolymer composition for the conveyor belt preferably contains the component (G) in the range of 5 to 120 parts by mass, more preferably 10 to 100 parts by mass, still more preferably 30 to 80 parts by mass, and particularly preferably 40 to 70 parts by mass, per 100 parts by mass of the total amount of the component (S) and the component (F), can contain the component (H) in the range of preferably 0.1 to 20 parts by mass, more preferably 2.0 to 15 parts by mass, still more preferably 5 to 12 parts by mass, and particularly preferably 8 to 10 parts by mass, and can contain the component (R) in the range of preferably 0.1 to 30 parts by mass, more preferably 2.0 to 25 parts by mass. The amount of the component (R) is more preferably 5 to 25 parts by mass, and particularly preferably 8 to 25 parts by mass. Here, in one exemplary embodiment of the present invention, the amount of the component (R) is 8 to 25 parts by mass. However, this does not prevent the amount of the component (R) from exceeding 25 parts by mass.

[0101] Furthermore, when the copolymer composition for the conveyor belt contains the component (J), the copolymer composition contains the component (J) in the range of preferably 0.1 to 30 parts by mass, more preferably 0.2 to 25 parts by mass, still more preferably 1 to 10 parts by mass, and particularly preferably 3 to 8 parts by mass, per 100 parts by mass of the total amount of the component (S) and the component (F). When two or more of the above components (G) are used in combination, the total amount of the two or more components (G) is within the range described above as the amount of the component (G), and the same applies to each of the above components (H), (R) and (J).

[0102] The copolymer composition for conveyor belts of the present invention may, according to the purpose, contain, in addition to the above components, other compounding agents, for example, at least one selected from co-crosslinking agents, crosslinking aids, anti-aging agents, processing aids, activators, heat stabilizers, weather stabilizers, antistatic agents, colorants, lubricants, thickeners, anti-foaming agents, foaming agents and foaming aids. Also, each additive may be used alone or in combination of two or more kinds.

[0103] <Co-crosslinking agent (L)> The copolymer composition for conveyor belts of the present invention may contain a co-crosslinking agent (L). Here, examples of the co-crosslinking agent (L) that can be used in the present invention include metal salts of α,β-unsaturated carboxylic acids. Examples of the metal salt of α,β-unsaturated carboxylic acid preferably include at least one compound selected from metal salts of acrylic acid, metal salts of methacrylic acid and metal salts of maleic acid.

[0104] Examples of the above acrylic acid metal salts, methacrylic acid metal salts and maleic acid metal salts include alkali metal salts (e.g., lithium salts, sodium salts, potassium salts), alkaline earth metal salts (e.g., magnesium salts, calcium salts), heavy metal salts (e.g., zinc salts), and aluminum salts of acrylic acid, methacrylic acid and maleic acid. Specifically, lithium acrylate, sodium acrylate, potassium acrylate, magnesium diacrylate, calcium diacrylate, zinc diacrylate, aluminum triacrylate, lithium methacrylate, sodium methacrylate, potassium methacrylate, zinc methacrylate, magnesium dimethacrylate, calcium dimethacrylate, zinc dimethacrylate, aluminum trimethacrylate, lithium maleate, sodium maleate, potassium maleate, magnesium maleate, zinc maleate, and aluminum maleate can be mentioned. As the α,β-unsaturated carboxylic acid metal salt, zinc methacrylate and zinc dimethacrylate are particularly preferred, and zinc methacrylate is most preferred. Also, magnesium dimethacrylate is also one of the particularly preferred examples of the α,β-unsaturated carboxylic acid metal salt. The α,β-unsaturated carboxylic acid metal salt may be used alone or in combination of two or more.

[0105] Such α,β-unsaturated carboxylic acid metal salts are optionally included in the copolymer composition for conveyor belts of the present invention. Based on 100 parts by mass of the total amount of the above component (S) and the above component (F), the total amount of all α,β-unsaturated carboxylic acid metal salts is usually 0.1 to 20 parts by mass, preferably 0.5 to 15 parts by mass, more preferably 1 to 10 parts by mass, and even more preferably 2 to 6 parts by mass. The copolymer composition for conveyor belts of the present invention preferably contains an α,β-unsaturated carboxylic acid metal salt as the co-crosslinking agent (L) because it improves the vulcanization rate and the physical properties of the resulting molded article are good. In addition, the copolymer composition for conveyor belts of the present invention may contain, as the co-crosslinking agent (L), in addition to the above-mentioned α,β-unsaturated carboxylic acid metal salts, crosslinking aids used in general rubber compositions.

[0106] <Crosslinking Aid> Examples of the crosslinking aid include sulfur; quinone dioxime-based crosslinking aids such as p-quinone dioxime; acrylic crosslinking aids such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; allyl crosslinking aids such as diallyl phthalate and triallyl isocyanurate; maleimide-based crosslinking aids; divinylbenzene; metal oxides such as zinc oxide (for example, two types of zinc oxide (JIS standard (K-1410)), zinc oxide manufactured by Hakusuitech Co., Ltd.), magnesium oxide, and zinc white (for example, zinc oxide such as "META-Z102" (trade name; manufactured by Inoue Lime Industry Co., Ltd.)).

[0107] When using a crosslinking aid, the compounding amount of the crosslinking aid in the copolymer composition for the conveyor belt is usually 0.5 to 10 moles, preferably 0.5 to 7 moles, more preferably 1 to 6 moles, per 1 mole of the organic peroxide-based crosslinking agent.

[0108] 〈Processing Aid〉 As the processing aid, those generally compounded with rubber as a processing aid can be widely used. Specifically, examples include ricinoleic acid, stearic acid, palmitic acid, lauric acid, barium stearate, zinc stearate, calcium stearate, zinc laurate, or esters. Among these, stearic acid is preferred.

[0109] When the copolymer composition for the conveyor belt contains a processing aid, it can be appropriately compounded in an amount of usually 0.1 to 3 parts by mass, preferably 0.2 to 2.5 parts by mass, more preferably 0.5 to 2.0 parts by mass, and still more preferably 0.8 to 1.5 parts by mass, based on 100 parts by mass of the total amount of component (S) and component (F). When the compounding amount of the processing aid is within the above range, it is suitable because it has excellent processability such as kneading processability, extrusion processability, and injection moldability. The processing aid may be used alone or in combination of two or more.

[0110] 〈Activator〉 Examples of the activator include amines such as di-n-butylamine, dicyclohexylamine, and monoethanolamine; activators such as diethylene glycol, polyethylene glycol, lecithin, triallyl trimellitate, and zinc compounds of aliphatic carboxylic acids or aromatic carboxylic acids; zinc peroxide preparations; and synthetic hydrotalcite.

[0111] When the copolymer composition for a conveyor belt contains an activator, the blending amount of the activator is usually 0.2 to 10 parts by mass, preferably 0.3 to 5 parts by mass, based on 100 parts by mass of the total amount of component (S) and component (F).

[0112] 〈Foaming agent and foaming aid〉 The molded body formed using the copolymer composition for a conveyor belt of the present invention may be a non-foamed body or a foamed body. When the conveyor belt is a foamed body, it is preferable that the copolymer composition for a conveyor belt contains a foaming agent.

[0113] As the foaming agent, any commercially available foaming agent can be preferably used. Examples of such foaming agents include inorganic foaming agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, and ammonium nitrite; nitroso compounds such as N,N'-dinitrosoterephthalamide and N,N'-dinitrosopentamethylenetetramine; azo compounds such as azodicarbonamide, azobisisobutyronitrile, azocyclohexylnitrile, azodiaminobenzene, and barium azodicarboxylate; sulfonylhydrazide compounds such as benzenesulfonylhydrazide, toluenesulfonylhydrazide, p,p'-oxybis(benzenesulfonylhydrazide), diphenylsulfone-3,3'-disulfonylhydrazide; and azide compounds such as calcium azide, 4,4'-diphenyldisulfonyl azide, and paratoluenemalonyl azide. Among them, azo compounds, sulfonylhydrazide compounds, and azide compounds are preferably used.

[0114] When the copolymer composition for the conveyor belt contains a foaming agent, the blending amount of the foaming agent is appropriately selected according to the performance required for the molded body produced from the copolymer composition. However, it is usually used in a proportion of 0.5 to 30 parts by mass, preferably 1 to 20 parts by mass, based on 100 parts by mass of the total amount of component (S) and component (F).

[0115] Also, a foaming aid may be used in combination with the foaming agent as necessary. The addition of the foaming aid is effective in adjusting the decomposition temperature of the foaming agent and making the bubbles uniform. Specific examples of the foaming aid include organic acids such as salicylic acid, phthalic acid, stearic acid, and oxalic acid, urea, and its derivatives.

[0116] When the copolymer composition for the conveyor belt contains a foaming aid, the blending amount of the foaming aid is usually used in a proportion of 1 to 100 parts by mass, preferably 2 to 80 parts by mass, based on 100 parts by mass of the foaming agent.

[0117] <Manufacturing method of the copolymer composition for the conveyor belt> The copolymer composition for a conveyor belt of the present invention can be obtained by a production method including a step of kneading the above component (S), the above component (F), the above component (K), the optional above component (G), the optional above component (H), and the optional above component (R), and, if necessary, processing aids, crosslinking aids, etc. with an internal mixer (closed mixer) such as a Banbury mixer, a kneader, or an intermix at a temperature of usually 80 to 170°C for 1 to 20 minutes, preferably at a temperature of 100 to 160°C for 1 to 10 minutes, more preferably at a temperature of 110 to 155°C for 1 to 5 minutes, and still more preferably at a temperature of 120 to 150°C for 1 to 3 minutes. Here, the copolymer composition for a conveyor belt containing the above component (J) is obtained by adding additives such as the above component (J), the co-crosslinking agent (L), a softening agent, and a vulcanization accelerator to the blend obtained by the above kneading step using rolls such as an open roll or a kneader, and, if necessary, additionally mixing a vulcanization accelerator and a crosslinking aid, and usually kneading at a roll temperature of 40 to 80°C for 5 to 30 minutes, preferably at a temperature of 40 to 70°C for 6 to 25 minutes, more preferably at a temperature of 45 to 65°C for 7 to 20 minutes, and still more preferably at a temperature of 45 to 60°C for 8 to 15 minutes, and then further performing a step of separating out.

[0118] Also, when the kneading temperature in the internal mixers is low, the component (J) may be kneaded simultaneously with components other than the component (J) such as the above component (S), the above component (F), the above component (K), the optional above component (G), the optional above component (H), and the optional above component (R).

[0119] <Conveyor Belt> The conveyor belt of the present invention is manufactured using the copolymer composition for a conveyor belt of the present invention. Here, since the copolymer composition for a conveyor belt of the present invention has both high wear resistance and high heat aging resistance while maintaining high wear resistance, the conveyor belt of the present invention can be used as a heat-resistant conveyor belt. The conveyor belt of the present invention includes the copolymer composition for a conveyor belt of the present invention, and specific configurations thereof include the following.

[0120] (CB1) A conveyor belt comprising a canvas as a core material and having an outer periphery coated with a copolymer composition for conveyor belts (that is, a conveyor belt including a core material made of canvas and a coating layer made of the copolymer composition for conveyor belts, wherein the coating layer covers the outer periphery of the core material). (CB2) A conveyor belt in which a steel cord is embedded as a core material in a copolymer composition for conveyor belts (that is, a conveyor belt including a core material made of a steel cord and a coating layer made of the copolymer composition for conveyor belts, wherein the coating layer covers the outer periphery of the core material).

[0121] The canvas is, for example, a canvas made of a woven fabric of synthetic fibers such as nylon, vinylon, and polyester. The number of laminated sheets of the canvas, the thickness of the copolymer composition for conveyor belts, the belt width, etc. are appropriately determined according to the intended use. However, the thickness of the copolymer composition for conveyor belts is usually about 1.5 to 20 mm.

[0122] The core material made of a steel cord is a steel cord formed by twisting a plurality of plain wires having a diameter of about 0.2 to 0.4 mm into a wire rope having a diameter of about 2.0 to 9.5 mm, and about 50 to 230 of such steel cords are arranged in parallel to form the core material. Generally, the total thickness of the conveyor belt is about 10 to 50 mm.

[0123] The conveyor belt of the present invention can be easily manufactured by interposing a canvas or a steel cord as a core material between uncrosslinked sheets formed from the copolymer composition for conveyor belts of the present invention according to a conventional method, and heating and pressurizing to effect crosslinking. The crosslinking conditions are usually 120 to 200 °C, more preferably 150 to 190 °C, 10 to 200 kg / cm 2 , more preferably 30 to 190 kg / cm 2 , still more preferably 50 to 190 kg / cm 2 for 5 to 90 minutes, more preferably 6 to 60 minutes, still more preferably 7 to 30 minutes, and particularly preferably 8 to 10 minutes.

Examples

[0124] Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples. In the following description, unless otherwise specified, "part" means "part by mass". Hereinafter, the present invention will be described more specifically based on examples, but the present invention is not limited to these examples at all.

[0125] [Measurement and Evaluation Methods] In the following examples and comparative examples, the measurement methods and evaluation methods for each physical property and characteristic are as follows.

[0126] (1) Physical Properties of Ethylene·α-Olefin·Non-Conjugated Polyene Copolymer (S) <Composition of Ethylene·α-Olefin·Non-Conjugated Polyene Copolymer (S)> For the ethylene·α-olefin·non-conjugated polyene copolymer (S), the molar ratio and mass fraction (mass %) of each structural unit are 13 determined by the measured values obtained by C-NMR. The measured values were obtained by using an ECX400P type nuclear magnetic resonance apparatus (manufactured by JEOL Ltd.) at a measurement temperature of 120 °C, a measurement solvent of orthodichlorobenzene / deuterated benzene = 4 / 1, and an integration number of 8000 times, and measuring the 13 C-NMR spectrum of the copolymer.

[0127] <Limiting Viscosity> The limiting viscosity [η] was measured at a temperature of 135 °C and a measurement solvent of decalin using an automatic limiting viscometer manufactured by Kureha Corporation.

[0128] <Complex Viscosity η * and P Value> As a rheometer, a viscoelasticity measuring device Ares (manufactured by Rheometric Scientific) was used, and at 190 °C and a strain of 1.0%, the complex viscosity η at a frequency ω = 0.01 rad / s * (ω=0.01) the complex viscosity η at a frequency ω = 0.1 rad / s * (ω=0.1) the complex viscosity η at a frequency ω = 10 rad / s *(ω=10) and the complex viscosity η at a frequency ω = 100 rad / s * (ω=100) (both in units of Pa·sec) were measured. Also, from the obtained results, η * (ω=0.1) and η * (ω=100) The ratio of the complex viscosities of η * ratio), the P value (η * (ω=0.1) / η * (ω=100) ) was calculated.

[0129] <Weight-average molecular weight (Mw) and the number of long-chain branches per 1000 carbon atoms (LCB 1000C )> were determined by the structural analysis method using the above-mentioned 3D-GPC.

[0130] (2) Physical properties of the copolymer composition for conveyor belts (unvulcanized rubber properties) <Mooney viscosity (ML (1+4) 125 °C)> The Mooney viscosity (ML (1+4) 125 °C) at 125 °C was measured using a Mooney viscometer (Model SMV202 manufactured by Shimadzu Corporation) in accordance with JIS K6300 under the condition of 125 °C.

[0131] <Vulcanization rate test> Using a vulcanization measuring device: MDR2000 (manufactured by ALPHATECHNOLOGIES), the vulcanization rate (tc90) of the copolymer composition for conveyor belts at 180 °C was measured under the measurement conditions of a temperature of 180 °C and a time of 20 minutes as follows. The torque change obtained under the conditions of a constant temperature and a constant shear rate was measured. The difference between the maximum value of torque (S'Max) and the minimum value of torque (S'Min): S'max - S'min [dNm], the time when the torque increased by 1 [dNm] after the torque of the measurement sample reached the lowest value S'min: TS1 [min], with the lowest value of torque S'min being 0% and the highest value S'max being 100%, the time [min] when the torque of the measurement sample reached 90%: tc90, and MCR [dNm / min] were determined. The smaller the tc90, the faster the vulcanization rate (crosslinking rate).

[0132] (3) Physical properties of the copolymer composition for conveyor belt (crosslinked product) (vulcanized rubber physical properties) <Modulus (MPa), tensile break stress (MPa), tensile break elongation (%)> The sheet was punched out to prepare a No. 3 dumbbell test piece described in JIS K 6251 (1993). Using this test piece, a tensile test was conducted according to the method specified in Paragraph 3 of JIS K6251 under the conditions of a measurement temperature of 25°C and a tensile speed of 500 mm / min, and the modulus (M 100 ) at 100% elongation, the tensile break stress (T B ) and the tensile break elongation (E B ) were measured.

[0133] <Durometer A hardness> According to JIS K 6253, the hardness measurement of the sheet (Type A durometer, HA) was carried out using six crosslinked sheets with a thickness of 2 mm having a smooth surface, stacking the flat parts to a thickness of about 12 mm. However, those with foreign matter mixed in the test piece, those with air bubbles, and those with scratches were not used. Also, the dimensions of the measurement surface of the test piece were set to a size where the tip of the pressing needle could be measured at a position more than 12 mm away from the edge of the test piece.

[0134] <Heat aging test> The sheet was subjected to a heat aging test in accordance with JIS K 6257 by holding it at 180 °C for 168 hours. The hardness, tensile breaking point stress (MPa), and tensile breaking point elongation (%) of the sheet after the heat aging test were measured in the same manner as in the items of <Durometer A hardness> and <Modulus (MPa), Tensile Breaking Point Stress (MPa), Tensile Breaking Point Elongation (%)>. From the difference in hardness before and after the heat aging test, AH (Duro - A) was determined, and from the tensile breaking point stress (T B ) and tensile breaking point elongation (E B ) before and after the heat aging test, the change rates after the test with respect to the values before the heat aging test were determined as Ac (T B ) and Ac (E B ), respectively.

[0135] <DIN Friction Test (Wear Amount)> In accordance with JIS - K6264 - 2:2005, three cross - linked sheets with a thickness of 2 mm were stacked to prepare a disc - shaped test piece with a diameter of 16.0 ± 0.2 mm and a thickness of 6 mm. For this test piece, using a DIN wear test machine, a drum with a diameter of 150.0 ± 0.2 mm and a length of 500 mm was rotated at 40 revolutions per minute, and the wear amount (DIN wear amount: unit mm 3 ) was measured with a load of 1 kgf and a wear distance of 40.0 ± 0.2 m.

[0136] <Tear Resistance Test> The tear resistance test was carried out by measuring the tear strength in accordance with JIS K6252:2007. A crescent - shaped test piece was cut out from a cross - linked sheet with a thickness of 2 mm, and a 1 - mm cut was made at the center of the concave part of the test piece. Then, for this test piece, using a tensile test machine, the tear strength was measured at a measurement environmental temperature of 23 °C and a tensile speed of 500 mm / min.

[0137] [Copolymer] In the examples and comparative examples, the following copolymers were used. (1) Ethylene·α - olefin·non - conjugated polyene copolymer (S) [Production Example 1] Production of Ethylene·α - olefin·non - conjugated polyene copolymer (S) Using a continuous polymerization apparatus, an ethylene-propylene-5-vinyl-2-norbornene (VNB) copolymer (S-1) was produced as follows.

[0138] Into a polymerization reactor with a volume of 300 liters, 58.3 L / hr of dehydrated and purified hexane solvent was continuously supplied from line 1, 4.5 mmol / hr of triisobutylaluminum (TiBA) was continuously supplied from line 2, and 6 H 5 ) 3 CB(C 6 F 5 ) 4 was continuously supplied at 0.150 mmol / hr, and di(p-tolyl)methylene(cyclopentadienyl)(octamethyl octahydrodibenzofluorenyl)zirconium dichloride was continuously supplied at 0.030 mmol / hr. At the same time, ethylene was continuously supplied into the polymerization reactor at 6.6 kg / hr, propylene at 9.3 kg / hr, hydrogen at 18 liters / hr, and VNB at 340 g / hr, each from separate lines, and copolymerization was carried out under the conditions of a polymerization temperature of 87°C, a total pressure of 1.6 MPaG, and a residence time of 1.0 hour.

[0139] The solution of the ethylene-propylene-VNB copolymer produced in the polymerization reactor was continuously discharged at a flow rate of 88.0 liters / hr, heated to 170°C (the pressure increased to 4.1 MPaG), and supplied to a phase separator. At this time, ethanol, which is a polymerization inhibitor, was continuously introduced into the discharge line in an amount 0.1 mol times that of TiBA in the liquid component withdrawn from the polymerization reactor.

[0140] In the phase separator, the solution of the ethylene-propylene-VNB copolymer was separated into a concentrated phase (lower phase part) containing most of the ethylene-propylene-VNB copolymer and a dilute phase (upper phase part) containing a small amount of polymer.

[0141] The separated concentrated phase was led to a heat exchanger at 85.4 liters / hr and further led into a hopper, where the solvent was evaporated and separated, and an ethylene-propylene-VNB copolymer was obtained in an amount of 7.8 kg / hr.

[0142] The composition and physical properties of the ethylene·propylene·VNB copolymer (S-1) obtained by the above Production Example 1 are as follows.

[0143] [Table 1]

[0144] (2) Ethylene·α-olefin copolymer (F) (2-1) Ethylene·1-butene copolymer (F1-1) Density: 864 kg / m 3 , Melting point: <50 °C, MFR: 3.6 g / 10 min, Mooney viscosity ML (1+4) 100 °C: 16 [Trade name: Toughmer TM DF640, manufactured by Mitsui Chemicals] (2-2) Ethylene·1-butene copolymer (F1-2) Density: 864 kg / m 3 , Melting point: <50 °C, MFR: 1.2 g / 10 min, Mooney viscosity ML (1+4) 100 °C: 40 [Trade name: Toughmer TM DF610, manufactured by Mitsui Chemicals] (2-3) Ethylene·propylene copolymer (F2-1) Density: 870 kg / m 3 , Melting point: 102 °C, Mooney viscosity ML (1+4) 100 °C: 40 [Trade name: Mitsui EPT TM 0045, manufactured by Mitsui Chemicals]

[0145] [Example 1] As a first step, using a BB-4 type Banbury mixer (manufactured by Kobe Steel, Ltd.), 40 parts by mass of the ethylene·α-olefin·non-conjugated polyene copolymer (S-1) obtained in Production Example 1 and 60 parts by mass of the ethylene·1-butene copolymer (F1-1) were kneaded for 1 minute, and then to this, 5 parts by mass of zinc white (ZnO#1, manufactured by Hakusuitec Co., Ltd.), 50 parts by mass of carbon black (G-1) (VULCAN 3D, manufactured by Cabot), 3 parts by mass of a phenolic antioxidant (trade name Irganox 1010, manufactured by BASF) as an antioxidant (H-1), 6 parts by mass of an imidazole-based antioxidant (trade name Sandant MB, manufactured by Sanshin Chemical Industry Co., Ltd.) as an antioxidant (H-2), 1 part by mass of stearic acid, 10 parts by mass of a dialkyl (C14 - C18) dimethylammonium chloride (trade name Lipcard 2HT, manufactured by Lion Specialty Chemicals) as an onium salt (K-1), and 10 parts by mass of a hydrocarbon-based lubricating oil (ethylene·α-olefin co-oligomer, trade name Lucant HC-3000X, manufactured by Mitsui Chemicals, Inc.) as a plasticizer (R-2) were added and kneaded at 140°C for 2 minutes. Then, the ram was raised for cleaning, and further kneaded for 1 minute, and the kneaded product was discharged at about 150°C to obtain the first-stage formulation.

[0146] Next, as a second step, the formulation obtained in the first step was wound around a 6-inch roll (manufactured by Nippon Roll Co., Ltd., surface temperature of the front roll 50°C, surface temperature of the rear roll 50°C, rotational speed of the front roll 16 rpm, rotational speed of the rear roll 18 rpm), and to this, 3.4 parts by mass of dicumyl peroxide (DCP) (trade name Perkyl (registered trademark) D-40, manufactured by NOF Corporation, diluted product with an inert filler (DCP purity 40%)) as an organic peroxide-based crosslinking agent (J-1) and 2.4 parts by mass of magnesium dimethacrylate (trade name Hicross GT, manufactured by Seiko Chemical Co., Ltd.) as a co-crosslinking agent (L-2) were added and kneaded for 10 minutes to obtain an uncrosslinked copolymer composition for a conveyor belt. The physical properties of this copolymer composition were evaluated.

[0147] After extruding the uncrosslinked copolymer composition for a conveyor belt into a sheet shape, using a 100-ton press, 150 kg / cm 2At a pressure of , it was pressed at 180 °C for 10 minutes to prepare a crosslinked sheet with a thickness of 2 mm. Using this, the physical properties of the crosslinked sheet were measured. The results are shown in Tables 2A and 3A. Note that in this example, the tear resistance test of the crosslinked sheet was not conducted.

[0148] [Comparative Example 1] In the first stage, without adding the onium salt (K-1), instead of the plasticizer (R-2), 10 parts by mass of process oil (trade name Diana Process PW-380, manufactured by Idemitsu Kosan Co., Ltd.) was added as the plasticizer (R-1), and in the second stage, instead of the co-crosslinking agent (L-2), 1.3 parts by mass of triallyl isocyanurate (TAIC) [trade name Tike, manufactured by Shinryo Corporation] was added as the co-crosslinking agent (L-1), and the same procedure as in Example 1 was carried out. The physical properties of the obtained uncrosslinked copolymer composition for conveyor belts and the crosslinked sheet were measured. The results are shown in Tables 2A and 3A. Note that in this comparative example, the tear resistance test of the crosslinked sheet was not conducted.

[0149] [Example 2] In the first stage, the blending amount of the ethylene·α-olefin·non-conjugated polyene copolymer (S-1) was changed to 20 parts by mass, in addition to 60 parts by mass of the ethylene·1-butene copolymer (F1-1), 20 parts by mass of the ethylene·propylene copolymer (F2-1) was added, the blending amount of the onium salt (K) was changed to 5 parts by mass, the blending amount of the plasticizer (R-2) was changed to 16 parts by mass, and in the second stage, the blending amount of the organic peroxide-based crosslinking agent (J-1) was changed to 4.4 parts by mass, and the blending amount of the co-crosslinking agent (L-2) was changed to 3.0 parts by mass, and the same procedure as in Example 1 was carried out. The physical properties of the obtained uncrosslinked copolymer composition for conveyor belts and the crosslinked sheet were measured. The results are shown in Tables 2A and 3A.

[0150] [Example 3] In the first stage, the same procedure as in Example 2 was carried out except that the ethylene·1-butene copolymer (F1-2) was used instead of the ethylene·1-butene copolymer (F1-1). The physical properties of the obtained uncrosslinked copolymer composition for conveyor belts and the crosslinked sheet were measured. The results are shown in Tables 2A and 3A.

[0151] [Example 4] In the second stage, the same procedure as in Example 3 was carried out except that 3.6 parts by mass of zinc methacrylate [trade name: Sunester SK-30, manufactured by Sanshin Chemical Industry Co., Ltd.] was added as the co-crosslinking agent (L-3) instead of the co-crosslinking agent (L-2). The physical properties of the obtained uncrosslinked copolymer composition for conveyor belts and the crosslinked sheet were measured. The results are shown in Tables 2A and 3A.

[0152] [Example 5] In the second stage, the same procedure as in Example 2 was carried out except that 3.6 parts by mass of zinc methacrylate [trade name: Sunester SK-30, manufactured by Sanshin Chemical Industry Co., Ltd.] was added as the co-crosslinking agent (L-3) instead of the co-crosslinking agent (L-2). The physical properties of the obtained uncrosslinked copolymer composition for conveyor belts and the crosslinked sheet were measured. The results are shown in Tables 2A and 3A.

[0153] [Example 6] In the second stage, the same procedure as in Example 5 was carried out except that the blending amount of the organic peroxide crosslinking agent (J-1) was changed to 4.0 parts by mass. The physical properties of the obtained uncrosslinked copolymer composition for conveyor belts and the crosslinked sheet were measured. The results are shown in Tables 2B and 3B.

[0154] [Example 7] In the second stage, the same procedure as in Example 5 was carried out except that the blending amount of the organic peroxide crosslinking agent (J-1) was changed to 3.6 parts by mass and the blending amount of the co-crosslinking agent (L-3) was changed to 5.0 parts by mass. The physical properties of the obtained uncrosslinked copolymer composition for conveyor belts and the crosslinked sheet were measured. The results are shown in Tables 2B and 3B.

[0155] [Example 8] In the second stage, the same procedure as in Example 4 was carried out except that the blending amount of the organic peroxide crosslinking agent (J-1) was changed to 4.0 parts by mass. The physical properties of the obtained uncrosslinked copolymer composition for conveyor belts and the crosslinked sheet were measured. The results are shown in Tables 2B and 3B.

[0156] [Example 9] In the first stage, the compounding amount of carbon black (G-1) was changed to 46 parts by mass, and in the second stage, the compounding amount of the co-crosslinking agent (L-3) was changed to 5.0 parts by mass, and the procedure was the same as in Example 8. The physical properties of the obtained uncrosslinked copolymer composition for conveyor belts and the crosslinked sheet were measured. The results are shown in Table 2B and Table 3B.

[0157] [Example 10] In the second stage, the procedure was the same as in Example 9 except that the compounding amount of the organic peroxide crosslinking agent (J-1) was changed to 3.6 parts by mass. The physical properties of the obtained uncrosslinked copolymer composition for conveyor belts and the crosslinked sheet were measured. The results are shown in Table 2B and Table 3B.

[0158] [Table 2A]

[0159] [Table 2B]

[0160] [Table 3A]

[0161] [Table 3B] [Industrial Applicability]

[0162] The heat-resistant conveyor belt made of the copolymer composition for conveyor belts of the present invention is suitable as a conveyor belt for transporting sintered products and returned ore, coke, cement clinker, raw coal, special chemicals, various high-temperature powdery substances, etc. in sintering plants, coke plants, cement plants, and chemical plants.

Claims

1. an ethylene / α-olefin / non-conjugated polyene copolymer (S); An ethylene / α-olefin copolymer (F); Onium salt (K) Including, The ethylene / α-olefin / non-conjugated polyene copolymer (S) The polymer has a structural unit derived from ethylene (A), a structural unit derived from an α-olefin (B) having 3 to 20 carbon atoms, and a structural unit derived from a non-conjugated polyene (C) containing, in the molecule, two or more partial structures selected from the group consisting of the following general formulae (I) and (II), and 【Chemistry 1】 The following requirements (i) to (v) are satisfied: The ethylene / α-olefin copolymer (F) has a structural unit derived from ethylene (A) and a structural unit derived from an α-olefin (B') having 3 to 20 carbon atoms, The content of the onium salt (K) is 0.2 to 80 parts by mass per 100 parts by mass of the total content of the ethylene / α-olefin / non-conjugated polyene copolymer (S) and the ethylene / α-olefin copolymer (F). Copolymer composition for conveyor belt: (i) The molar ratio of ethylene to α-olefin is from 40 / 60 to 99.9 / 0.

1. (ii) The mass fraction of the structural units derived from the non-conjugated polyene (C) is 0.07% by mass to 10% by mass in 100% by mass of the ethylene / α-olefin / non-conjugated polyene copolymer. (iii) The weight average molecular weight (Mw) of the ethylene-α-olefin-non-conjugated polyene copolymer, the mass fraction of the constituent unit derived from the non-conjugated polyene (C) (mass fraction (mass %) of (C)), and the molecular weight of the non-conjugated polyene (C) (molecular weight of (C)) satisfy the following formula (1): 4.5≦Mw×mass fraction of (C) / 100 / molecular weight of (C)≦80...Equation (1) (iv) Complex viscosity η at frequency ω = 0.1 rad / s obtained by linear viscoelastic measurement (190°C) using a rheometer * (ω=0.1) (Pa sec) and the complex viscosity η at a frequency ω = 100 rad / s * (ω=100) (Pa sec) P(η * (ω=0.1) / * (ω=100) ), the intrinsic viscosity [η], and the mass fraction of the structural unit derived from the non-conjugated polyene (C) (mass fraction of (C)) satisfy the following formula (2). P / ([η] 2.9 ) ≦ mass fraction of (C) × 6 ... formula (2) (v) Long Chain Branches (LCB) per 1000 carbon atoms obtained using 3D-GPC 1000C ) and the natural logarithm of the weight average molecular weight (Mw) [Ln(Mw)] satisfy the following formula (3). LCB 1000C ≦1-0.07×Ln(Mw)・・・Formula (3)

2. The copolymer composition for a conveyor belt according to claim 1, wherein the ethylene-α-olefin-non-conjugated polyene copolymer (S) satisfies the following formula (1'): 45≦Mw×mass fraction of (C) / 100 / molecular weight of (C)≦80...formula (1′)

3. 2. The copolymer composition for a conveyor belt according to claim 1, wherein the ethylene / α-olefin copolymer (F) has a melting point of 150° C. or lower.

4. 2. The copolymer composition for a conveyor belt according to claim 1, wherein a content ratio of the ethylene-α-olefin-non-conjugated polyene copolymer (S) relative to a total of 100 parts by mass of the ethylene-α-olefin-non-conjugated polyene copolymer (S) and the ethylene-α-olefin copolymer (F) is more than 0 parts by mass and 70 parts by mass or less.

5. 2. The copolymer composition for a conveyor belt according to claim 1, wherein the ethylene / α-olefin copolymer (F) comprises an ethylene / α-olefin copolymer (F1) having a constitutional unit derived from ethylene (A) and a constitutional unit derived from an α-olefin (B′1) having 4 to 20 carbon atoms.

6. 6. The copolymer composition for a conveyor belt according to claim 5, wherein the ethylene / α-olefin copolymer (F) further comprises an ethylene / α-olefin copolymer (F2) having a constitutional unit derived from ethylene (A) and a constitutional unit derived from an α-olefin (B'2) having 3 carbon atoms.

7. 2. The copolymer composition for a conveyor belt according to claim 1, further comprising at least one selected from the group consisting of the following components (G), (H) and (R): Component (G): Carbon black (G) Component (H): Antiaging Agent (H) Component (R): Plasticizer (R)

8. 8. The copolymer composition for a conveyor belt according to claim 7, wherein the plasticizer (R) is a hydrocarbon-based synthetic lubricating oil.

9. Total amount of ethylene / α-olefin / non-conjugated polyene copolymer (S) and ethylene / α-olefin copolymer (F): per 100 parts by mass The ethylene / α-olefin / non-conjugated polyene copolymer (S) is more than 0 parts by mass and 70 parts by mass or less, The ethylene / α-olefin copolymer (F) is 30 parts by mass or more and less than 100 parts by mass, 5 to 120 parts by mass of the component (G), 0.1 to 20 parts by mass of the component (H), and 0.1 to 30 parts by mass of the component (R) The copolymer composition for a conveyor belt according to claim 7, comprising

10. The copolymer composition for a conveyor belt according to claim 1, further comprising the following component (J): Component (J): Organic peroxide-based crosslinking agent (J)

11. The copolymer composition for a conveyor belt according to claim 1, wherein the ethylene-α-olefin-non-conjugated polyene copolymer (S) further has an intrinsic viscosity [η] of 0.1 to 5.0 dL / g and a weight average molecular weight (Mw) of 100,000 to 800,000.

12. 2. The copolymer composition for a conveyor belt according to claim 1, wherein the non-conjugated polyene (C) is 5-vinyl-2-norbornene (VNB).

13. A heat-resistant conveyor belt obtained by using the copolymer composition for conveyor belts according to any one of claims 1 to 12.

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