JP2023148493A - Copolymer composition for conveyor belts and applications thereof - Google Patents

Abstract

To provide a copolymer composition for conveyor belts that is suitable for obtaining a conveyor belt having excellent workability, mechanical properties, thermal aging resistance and wear resistance.SOLUTION: A copolymer composition for conveyor belts includes an ethylene α-olefin nonconjugated polyene copolymer (S), an ethylene α-olefin copolymer (F), a modified ethylene α-olefin copolymer (K), a nonpolar hydrocarbon-based oil (E), carbon black (G) and an aging resister (H).SELECTED DRAWING: None

Description

The present invention relates to a copolymer composition for conveyor belts that has excellent processability, mechanical properties, heat aging resistance, and abrasion resistance.

In various industrial fields such as steel, coal, and cement, belt conveyor equipment is used as a means of transporting goods, and in particular, high-temperature goods of about 150 to 250°C, such as clinker, are transported by belt conveyor equipment. There are many cases. Under these circumstances, there is a need for conveyor belts with excellent heat aging resistance and wear resistance in order to minimize maintenance work and extend the service life.

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

Japanese Patent Application Publication No. 11-246017

However, in recent years, there has been an increasing demand for higher abrasion resistance for conveyor belts, and a rubber composition for heat-resistant conveyor belts that replaces conventional products maintains the same heat resistance, mechanical properties, and processability as conventional products. It is desired that the performance be as high as 100% or higher.

An object of the present invention is to obtain a copolymer composition for a conveyor belt that is suitable for obtaining a conveyor belt that has excellent processability, mechanical properties, heat aging resistance, and abrasion resistance.

As a result of studies to solve the above-mentioned problems, the present inventors discovered that the above-mentioned problems could be solved by a composition having the following structure, and completed the present invention.
The present invention relates to a copolymer composition for conveyor belts, characterized by containing the following components (S), (F), (K), (E), (G), and (H).
(S) Ethylene (A), α-olefin having 3 to 20 carbon atoms (B), and a total of two partial structures selected from the group consisting of the following general formulas (I) and (II) in the molecule. An ethylene/α-olefin/non-conjugated polyene copolymer that has a structural unit derived from the above-mentioned non-conjugated polyene (C) and satisfies the following requirements (i) to (v);
(F) an ethylene/α-olefin copolymer containing ethylene and an α-olefin having 3 to 20 carbon atoms;
(K) modified ethylene/α-olefin copolymer;
(E) non-polar hydrocarbon oil;
(G) carbon black;
(H) Anti-aging agent;
Ethylene/α-olefin/non-conjugated polyene copolymer (S);
(i) The molar ratio of ethylene/α-olefin is 40/60 to 99.9/0.1.
(ii) The weight fraction of the structural unit derived from the non-conjugated polyene (C) is 0.07% by weight to 10% by weight based on 100% by weight of the ethylene/α-olefin/non-conjugated polyene copolymer.
(iii) Weight average molecular weight (Mw) of the ethylene/α-olefin/non-conjugated polyene copolymer and the weight fraction of structural units derived from the non-conjugated polyene (C) (weight fraction of (C) (wt%) )) and the molecular weight of the non-conjugated polyene (C) (molecular weight of (C)) satisfy the following formula (1).
4.5≦Mw×weight fraction of (C)/100/molecular weight of (C)≦40...Formula (1)
(iv) Complex viscosity η ^* ₍ ω _=0.1) (Pa sec) at frequency ω = 0.1 rad/s obtained by linear viscoelasticity measurement (190°C) using a rheometer, and frequency ω = The ratio P (η ^* ₍ ω _=0.1) /η ^* ₍ ω ₌₁₀₀₎ ) to the complex viscosity η ^* ₍ ω ₌₁₀₀₎ (Pa・sec) at 100 rad/s, the limiting viscosity [η], and the above The weight fraction of the structural unit derived from the non-conjugated polyene (C) (the weight fraction of (C)) satisfies the following formula (2).
P/([η] ^2.9 )≦weight fraction of (C)×6...Formula (2)
(v) The number of long chain branches per 1000 carbon atoms (LCB _1000C ) obtained using 3D-GPC and the natural logarithm [Ln (Mw)] of the weight average molecular weight (Mw) are expressed by the following formula (3) satisfy.
LCB _1000C ≦1-0.07×Ln(Mw)...Formula (3)

The copolymer composition for a heat-resistant conveyor belt of the present invention can be made into a heat-resistant conveyor belt having high wear resistance while maintaining processability, mechanical properties, and heat aging resistance.

<Ethylene/α-olefin/non-conjugated polyene copolymer (S)>
Ethylene/α-olefin/non-conjugated polyene copolymer (S), which is one of the components contained in the copolymer composition for conveyor belts of the present invention [hereinafter may be abbreviated as "component (S)"] . ] has a total of two partial structures selected from the group consisting of ethylene (A), an α-olefin having 3 to 20 carbon atoms (B), and the following general formulas (I) and (II) in the molecule. It has a structural unit derived from the above-mentioned non-conjugated polyene (C).

In addition to the structural units derived from the above (A), (B), and (C), the component (S) according to the present invention further has a partial structure selected from the group consisting of the above general formulas (I) and (II). It may have a structural unit derived from a non-conjugated polyene (D) containing only one in the molecule.

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- Examples include decene, 1-dodecene, 1-tetradecene, 1-hexadecene, and 1-eicosene. Among these, α-olefins having 3 to 8 carbon atoms such as propylene, 1-butene, 1-hexene, and 1-octene are preferred, and propylene is particularly preferred. Such α-olefins have relatively low raw material costs, the resulting copolymer composition for conveyor belts exhibits excellent mechanical properties, and conveyor belts with rubber elasticity can be obtained. preferable. These α-olefins may be used alone or in combination of two or more.

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

Examples of the non-conjugated polyene (C) containing a total of two or more partial structures selected from the group consisting of general formulas (I) and (II) in the molecule include 5-vinyl-2-norbornene (VNB), norbornadiene, Examples include 1,4-hexadiene and dicyclopentadiene. Among these, non-conjugated polyene (C ) preferably contains VNB, and more preferably the non-conjugated polyene (C) is VNB. The non-conjugated polyene (C) may be used alone or in combination of two or more.

In addition to the structural units derived from ethylene (A), the α-olefin having 3 to 20 carbon atoms (B), and the non-conjugated polyene (C), the component (S) according to the present invention further contains the structural units derived from the general formula It may contain a structural unit derived from a non-conjugated polyene (D) containing only one partial structure selected from the group consisting of (I) and (II) in the molecule. Examples of such non-conjugated polyenes (D) include 5-ethylidene-2-norbornene (ENB), 5-methylene-2-norbornene, 5-(2-propenyl)-2-norbornene, and 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) Examples include -2-norbornene. Among these, ENB is preferred because it is easily available, has high reactivity with sulfur and vulcanization accelerator during the crosslinking reaction after polymerization, is easy to control the crosslinking rate, and is easy to obtain good mechanical properties. . The non-conjugated polyene (D) may be used alone or in combination of two or more.

The ethylene/α-olefin/non-conjugated polyene copolymer (S) according to the present invention is a non-conjugated polyene containing only one partial structure selected from the group consisting of general formulas (I) and (II) in the molecule. When a structural unit derived from (D) is included, its proportion is not particularly limited as long as it does not impair the purpose of the present invention, but is usually 0 to 20% by weight, preferably 0 to 8% by weight, more preferably 0 to 8% by weight. It is preferably included in a weight fraction of about 0.01 to 8% by weight (provided that the total weight fraction of (A), (B), (C), and (D) is 100% by weight).

As mentioned above, the component (S) according to the present invention includes ethylene (A), an α-olefin having 3 to 20 carbon atoms (B), the above non-conjugated polyene (C), and optionally the above non-conjugated polyene (C). A copolymer having a structural unit derived from a conjugated polyene (D), which satisfies the following requirements (i) to (v).

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

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

[Requirement (iii)]
The weight average molecular weight (Mw) of the ethylene/α-olefin/non-conjugated polyene copolymer (S) and the weight fraction of the structural unit derived from the non-conjugated polyene (C) (the weight fraction of (C) (wt%) )) and the molecular weight of the non-conjugated polyene (C) (molecular weight of (C)) satisfy the following formula (1).
4.5≦Mw×weight fraction of (C)/100/molecular weight of (C)≦40...Formula (1)

[Requirement (iv)]
Complex viscosity η ^* ₍ ω _=0.1) (Pa sec) at frequency ω = 0.1 rad/s and frequency ω = 100 rad/s obtained by linear viscoelasticity measurement (190°C) using a rheometer The ratio P (η ^* ₍ ω = _{0.1 )} /η ^* ₍ ω _{=100) ) to the complex viscosity η * ( ω =100)} (Pa・_sec ⁾ at The weight fraction of the structural unit derived from (C) (the weight fraction of (C)) satisfies the following formula (2).
P/([η] ^2.9 )≦weight fraction of (C)×6...Formula (2)

[Requirement (v)]
The number of long chain branches per 1000 carbon atoms (LCB _1000C ) obtained using 3D-GPC and the natural logarithm [Ln (Mw)] of the weight average molecular weight (Mw) satisfy the following formula (3).
LCB _1000C ≦1-0.07×Ln(Mw)...Formula (3)
In this specification, "α-olefin having 3 to 20 carbon atoms" is also simply referred to as "α-olefin."

[Requirement (i)]
Requirement (i) is that the molar ratio of ethylene/α-olefin in the ethylene/α-olefin/non-conjugated polyene copolymer (S) according to the present invention satisfies 40/60 to 99.9/0.1. This molar ratio preferably satisfies 50/50 to 90/10, more preferably 55/45 to 85/15, and even more preferably 55/45 to 78/22. When the ethylene/α-olefin/nonconjugated polyene copolymer (S) according to the present invention is used as a raw material for a crosslinked molded product, the resulting crosslinked molded product exhibits excellent rubber elasticity and mechanical properties. This is preferable because it provides excellent strength and flexibility.

In addition, the amount of ethylene (content of structural units derived from ethylene (A)) and the amount of α-olefin (structure derived from α-olefin (B)) in the ethylene/α-olefin/non-conjugated polyene copolymer (S) The unit content) can be determined by ¹³ C-NMR.

[Requirement (ii)]
Requirement (ii) is that the component (S) according to the present invention has a weight fraction of structural units derived from the non-conjugated polyene (C) that is higher than the ethylene/α-olefin/non-conjugated polyene copolymer (S). ) in 100% by weight (ie, in the total 100% by weight of the weight fractions of all structural units), it specifies that it is in the range of 0.07% by weight to 10% by weight. The weight fraction of the structural units derived from this non-conjugated polyene (C) is preferably 0.1% to 8.0% by weight, more preferably 0.5% to 5.0% by weight. desirable.

When the component (S) according to the present invention satisfies the requirement (ii), the component (S) according to the present invention has sufficient hardness and has excellent mechanical properties, which is preferable. When crosslinked, the crosslinking rate is high, and the component (S) according to the present invention is preferable because it is suitable for producing a crosslinked molded product.
The amount of non-conjugated polyene (C) (content of structural units derived from non-conjugated polyene (C)) in the ethylene/α-olefin/non-conjugated polyene copolymer (S) can be determined by ¹³ C-NMR. I can do it.

[Requirement (iii)]
Requirement (iii) is the weight average molecular weight (Mw) of the ethylene/α-olefin/non-conjugated polyene copolymer (S) of the ethylene/α-olefin/non-conjugated polyene copolymer (S) according to the present invention; The weight fraction of the structural unit derived from the non-conjugated polyene (C) during coalescence (weight fraction of (C): weight %) and the molecular weight of the non-conjugated polyene (C) (molecular weight of (C)) are This specifies that the following relational expression (1) is satisfied.
4.5≦Mw×weight fraction of (C)/100/molecular weight of (C)≦40...Formula (1)

When the ethylene/α-olefin/non-conjugated polyene copolymer (S) according to the present invention satisfies requirement (iii), the content of structural units derived from the non-conjugated polyene (C) such as VNB is appropriate. In addition to exhibiting sufficient crosslinking performance, when a crosslinked molded product is produced using the ethylene/α-olefin/nonconjugated polyene copolymer of the present invention, the crosslinking rate is excellent, and the molded product after crosslinking is excellent. This is preferable because it exhibits good mechanical properties.

The ethylene/α-olefin/nonconjugated polyene copolymer (S) according to the present invention more preferably satisfies the following relational formula (1').
4.5≦Mw×weight fraction of (C)/100/molecular weight of (C)≦35...Formula (1')
The weight average molecular weight (Mw) of the ethylene/α-olefin/nonconjugated polyene copolymer (S) can be determined as a polystyrene-equivalent value measured by gel permeation chromatography (GPC).

The ethylene/α-olefin/non-conjugated polyene copolymer (S) according to the present invention has the formula (1) or (1' ), the degree of crosslinking is appropriate, and by using this it is possible to produce molded products with well-balanced mechanical properties and heat aging resistance. If "Mw x weight fraction of (C)/100/molecular weight of (C)" is too small, the crosslinking property may be insufficient and the crosslinking speed may be slow; if it is too large, the crosslinking rate may be slow. may occur, resulting in deterioration of mechanical properties.

[Requirement (iv)]
Requirement (iv) is the frequency ω=0.1 rad/s obtained by linear viscoelasticity measurement (190°C) of the ethylene/α-olefin/nonconjugated polyene copolymer according to the present invention using a rheometer. ^The _{ratio P ( η} ^{* (} _{ω = 0.1)} /η ^* ₍ ω ₌₁₀₀₎ ), the intrinsic viscosity [η], and the weight fraction of the structural unit derived from the non-conjugated polyene (C) (weight fraction of (C): weight %) are , which specifies that the following formula (2) is satisfied.
P/([η] ^2.9 )≦weight fraction of (C)×6...Formula (2)

_Here ^, _{the ratio} P( ^{η *} _{( ω =0.1)} /η ^* ₍ ω ₌₁₀₀₎ ) represents the frequency dependence of viscosity, and P/([η] ^2.9 ), which is the left side of equation (2), represents short chain branching, molecular weight, etc. Although there is an influence, it tends to show a high value when there are many long chain branches. In general, ethylene/α-olefin/non-conjugated polyene copolymers tend to contain more long chain branches as they contain more structural units derived from non-conjugated polyenes. It is thought that the non-conjugated polyene copolymer (S) can satisfy the above formula (2) because it has fewer long chain branches than conventionally known ethylene/α-olefin/non-conjugated polyene copolymers. In the present invention, the P value is the complex viscosity at 0.1 rad/s obtained by measuring using a viscoelasticity measuring device Ares (manufactured by Rheometric Scientific) at 190°C, 1.0% strain, and varying frequencies. The ratio (η* ratio) was calculated from the complex viscosity at 100 rad/s.

The ethylene/α-olefin/nonconjugated polyene copolymer (S) according to the present invention preferably satisfies the following formula (2').
P/([η] ^2.9 )≦Weight fraction of (C)×5.7...Formula (2')
Note that the intrinsic viscosity [η] means a value measured in decalin at 135°C.

[Requirement (v)]
Requirement (v) is the number of long chain branches per 1000 carbon atoms (LCB _1000C ) obtained using 3D-GPC and the weight average molecular weight of the ethylene/α-olefin/nonconjugated polyene copolymer (S). This specifies that the natural logarithm [Ln(Mw)] of (Mw) satisfies the following formula (3).
LCB _1000C ≦1-0.07×Ln(Mw)...Formula (3)

The above formula (3) specifies the upper limit of the long chain branching content per unit carbon number of the ethylene/α-olefin/nonconjugated polyene copolymer (S).

Such an ethylene/α-olefin/nonconjugated polyene copolymer (S) contains a small proportion of long chain branches, and has excellent curing properties when crosslinking with peroxide. This is preferable because the molded product obtained by this process has excellent heat aging resistance.

The ethylene/α-olefin/nonconjugated polyene copolymer (S) according to the present invention preferably satisfies the following formula (3').
LCB _1000C ≦1-0.071×Ln(Mw)...Formula (3')
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.

The absolute molecular weight distribution was determined using a 3D-high temperature GPC device PL-GPC220 (manufactured by Polymer Laboratories), and at the same time, the intrinsic viscosity was determined using a viscometer. The main measurement conditions are as follows.
Detector: Differential refractometer/GPC device built-in 2-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 x 2 + TSKgel GMH _HR -M(S) x 1 (inner diameter 7.8mmφ x length 300mm per column)
Temperature: 140℃
Mobile phase: 1,2,4-trichlorobenzene (containing 0.025% BHT)
Injection volume: 0.5mL
Sample concentration: ca 1.5mg/mL
Sample filtration: Filtered with a sintered filter with a pore size of 1.0 μm The dn/dc value required to determine the absolute molecular weight is based on the dn/dc value of standard polystyrene (molecular weight 190000) of 0.053 and the response intensity of the differential refractometer per unit injection mass. , determined for each sample.

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 obtained from the viscometer and the absolute molecular weight obtained from the light scattering photometer.

Here, the relational expression [η]=KM ^v ;v=0.725 was applied.
In addition, each average value of g' was calculated from the following formulas (v-2), (v-3), and (v-4). Note that the Trendline, which was assumed to have only short chain branches, was determined for each sample.

Furthermore, using g'w, the number of branching points BrNo per molecular chain, the number of long chain branches LCB _1000C per 1000 carbons, and the degree of branching λ per unit molecular weight were calculated. The Zimm-Stockmayer formula (v-5) was used to calculate BrNo, and the formulas (v-6) and (v-7) were used to calculate LCB _1000C and λ. g is a long chain branching parameter determined from the radius of inertia Rg, and the following simple correlation is made between it and g' determined from the intrinsic viscosity. Various values have been proposed for ε in the formula depending on the shape of the molecule. Here, calculations were performed on the assumption that ε=1 (ie, g'=g).

λ=BrNo/M...(V-6)
LCB _1000C = λ×14000...(V-7)
*In formula (V-7), 14,000 represents the molecular weight of 1,000 methylene (CH ² ) units.

The ethylene/α-olefin/nonconjugated polyene copolymer (S) according to the present invention preferably has an intrinsic viscosity [η] of 0.1 to 5 dL/g, more preferably 0.5 to 5.0 dL/g, More preferably, it is 0.9 to 4.0 dL/g.

Further, the ethylene/α-olefin/non-conjugated polyene copolymer (S) according to the present invention preferably has a weight average molecular weight (Mw) of 10,000 to 600,000, more preferably 30,000 to 500,000, More preferably, it is 50,000 to 400,000.

It is preferable that the component (S) according to the present invention satisfies both the above intrinsic viscosity [η] and weight average molecular weight (Mw).
In the component (S) according to the present invention, the nonconjugated polyene (C) preferably contains VNB, more preferably VNB. That is, in the above-mentioned formulas (1) and (2), as well as the formula (4) described later, etc., it is preferable that "weight fraction of (C)" is "weight fraction of VNB" (weight %).

As mentioned above, the component (S) according to the present invention further consists of the above general formulas (I) and (II) in addition to the structural units derived from the above (A), (B) and (C). The structural unit derived from the non-conjugated polyene (D) containing only one partial structure selected from the group in the molecule is added at a weight fraction of 0% to 20% by weight (provided that (A), (B), ( It is also preferable that the total weight fraction of C) and (D) be 100% by weight. In this case, it is preferable to satisfy the following requirement (vi).

[Requirement (vi)]
The weight average molecular weight (Mw) of the ethylene/α-olefin/non-conjugated polyene copolymer, the weight fraction of the structural unit derived from the non-conjugated polyene (C) (the weight fraction (weight %) of (C)), and , the weight fraction of the structural unit derived from the conjugated polyene (D) (the weight fraction (weight %) of (D)), the molecular weight of the non-conjugated polyene (C) (the molecular weight of (C)), and the conjugated polyene ( The molecular weight of D) (the molecular weight of (D)) satisfies the following formula (4).
4.5≦Mw×{(weight fraction of (C)/100/molecular weight of (C))+(weight fraction of (D)/100/molecular weight of (D))}≦45...Formula ( 4)
Formula (4) specifies the content of non-conjugated diene (total of (C) and (D)) in one molecule of the copolymer.

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

Requirement (vi) is not met and "Mw x {(weight fraction of (C)/100/molecular weight of (C)) + (weight fraction of (D)/100/(D)" in formula (4) If the amount of molecular weight (molecular weight of Mechanical properties may deteriorate, and heat aging resistance may also deteriorate.

[Requirement (vii)]
The component (S) according to the present invention is not particularly limited, but the complex viscosity η ^* at frequency ω = 0.01 rad/s obtained by linear viscoelasticity measurement (190°C) using a rheometer ₍ ω _=0.01) (Pa・sec), the complex viscosity η ^* ₍ ω ₌₁₀₎ (Pa・sec) at frequency ω=10 rad/s, and the apparent iodine value derived from the nonconjugated polyene (c). preferably satisfies the following formula (5).
Log{η ^* ₍ ω _=0.01) }/Log{η ^* ₍ ω ₌₁₀₎ }≦0.0753×{apparent iodine value derived from non-conjugated polyene (C)}+1.42...Equation (5 )
Here, complex viscosity η ^* ₍ ω _=0.01) and complex viscosity η * ₍ ω ₌₁₀₎ are measured as complex viscosity ^{η * (} _{ω =0.1)} and complex viscosity η ^* ₍ ω ₌₁₀₀₎ in requirement (vi). Everything except the frequency can be found in the same way.

Further, the apparent iodine value derived from the non-conjugated polyene (C) is determined by the following formula.
Apparent iodine value derived from (C) = weight fraction of (C) x 253.81/molecular weight of (C) In the above formula (5), the left side represents the shear rate dependence, which is an indicator of the amount of long chain branching, The right side represents an index of the content of non-conjugated polyene (C) that is not consumed as long chain branches during polymerization. When requirement (vii) is satisfied and the above formula (5) is satisfied, the degree of long chain branching is not too high, which is preferable. On the other hand, if the above formula (5) is not satisfied, it can be seen that a large proportion of the copolymerized non-conjugated polyene (C) is consumed in the formation of long chain branches.

Furthermore, the ethylene/α-olefin/non-conjugated polyene copolymer (S) according to the present invention preferably contains a sufficient amount of structural units derived from the non-conjugated polyene (C). The weight fraction of the structural unit derived from polyene (C) (weight fraction (weight %) of (C)) and the weight average molecular weight (Mw) of the copolymer satisfy the following formula (6). preferable.
6-0.45×Ln(Mw)≦Weight fraction of (C)≦10...Formula (6)

Furthermore, the ethylene/α-olefin/non-conjugated polyene copolymer (S) according to the present invention has a number (n _C ) of structural units derived from the non-conjugated polyene (C) per weight average molecular weight (Mw). The number is preferably 6 or more, more preferably 6 or more and 40 or less, still more preferably 7 or more and 39 or less, and even more preferably 10 or more and 38 or less.

Such an ethylene/α-olefin/non-conjugated polyene copolymer (S) according to the present invention contains a sufficient amount of structural units derived from a non-conjugated polyene (C) such as VNB, and contains long chain branches. It is small in amount, has excellent curing properties when crosslinked using peroxide, has good moldability, has an excellent balance of physical properties such as mechanical properties, and is particularly excellent in heat aging resistance.

Furthermore, the ethylene/α-olefin/non-conjugated polyene copolymer (S) according to the present invention has a number (n _D ) of structural units derived from the non-conjugated polyene (D) per weight average molecular weight (Mw). The number is preferably 29 or less, more preferably 10 or less, and even more preferably less than 1.

The ethylene/α-olefin/non-conjugated polyene copolymer (S) according to the present invention has a content of structural units derived from the non-conjugated polyene (D) such as ENB within a range that does not impair the purpose of the present invention. It is preferable because it is suppressed to 20%, is less likely to cause post-crosslinking, and has sufficient heat aging resistance.

Here, the number of structural units derived from the non-conjugated polyene (C) per weight average molecular weight (Mw) of the ethylene/α-olefin/non-conjugated polyene copolymer (n _C ) or the non-conjugated polyene (C) The number of derived structural units (n _D ) is determined by the molecular weight of the non-conjugated polyene (C) or (D) and the weight fraction of the structural units derived from the non-conjugated polyene (C) or (D) in the copolymer. (weight fraction (weight %) of (C) or (D))) and the weight average molecular weight (Mw) of the copolymer, it can be determined by the following formula.
(n _C )=(Mw)×{weight fraction of (C)/100}/molecular weight of non-conjugated polyene (C) (n _D )=(Mw)×{weight fraction of (D)/100}/ Molecular weight of non-conjugated polyene (D)

The ethylene/α-olefin/non-conjugated polyene copolymer (S) according to the present invention has a number of constituent units derived from the non-conjugated polyenes (C) and (D) per weight average molecular weight (Mw) ( When both n _c ) and n _D satisfy the above ranges, the ethylene/α-olefin/non-conjugated polyene copolymer has a low long chain branching content and the peroxide is used. It is preferable because it has excellent curing properties when crosslinked, has good moldability, and has an excellent balance of physical properties such as mechanical properties, is less likely to cause post-crosslinking, and has particularly excellent heat aging resistance.

<Production of ethylene/α-olefin/nonconjugated polyene copolymer (S)>
The ethylene/α-olefin/non-conjugated polyene copolymer (S) according to the present invention comprises ethylene (A), an α-olefin (B) having 3 to 20 carbon atoms, and the general formula (I) and ( A non-conjugated polyene (C) containing a total of two or more partial structures selected from the group consisting of II) in the molecule, and optionally a partial structure selected from the group consisting of the general formulas (I) and (II) above. It is a copolymer obtained by copolymerizing a monomer consisting of a non-conjugated polyene (D) containing only one 2 in the molecule in total.

The ethylene/α-olefin/nonconjugated polyene copolymer (S) according to the present invention may be prepared by any method as long as the above requirements (i) to (v) are met, but metallocene compounds It is preferably obtained by copolymerizing monomers in the presence of a metallocene compound, and more preferably it is obtained by copolymerizing monomers in the presence of a catalyst system containing a metallocene compound.

As a specific method for producing the above-mentioned copolymer (A) according to the present invention, for example, a production method using a metallocene catalyst described in JP 2018-119096 A and International Publication No. 2015/122495 pamphlet is adopted. It can be manufactured by

<Ethylene/α-olefin copolymer (F)>
Ethylene/α-olefin copolymer (F), which is one of the components contained in the copolymer composition for conveyor belts of the present invention [hereinafter may be abbreviated as "component (F)". ] is a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms.

As the α-olefin, an α-olefin having preferably 3 to 12 carbon atoms, more preferably 4 to 8 carbon atoms is desirable, since a conveyor belt with excellent mechanical strength can be obtained.
Specifically, such α-olefins 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, Examples include 11-methyl-1-dodecene and 12-ethyl-1-tetradecene. Among them, propylene, 1-butene, 1-hexene, 1-octene and the like are preferably used. These α-olefins may be used alone or in combination of two or more.

In component (F) according to the present invention, the content of structural units derived from ethylene is preferably 50 to 85 mol%, more preferably 50 to 80 mol% (however, the content of structural units derived from ethylene and carbon The total amount with the structural unit derived from an α-olefin having 3 to 20 atoms is 100 mol%). When the content of the structural unit derived from ethylene is within the above range, a copolymer composition for conveyor belts that has excellent compatibility with component (S) can be obtained.

Component (F) according to the present invention preferably satisfies the following requirements (i) to (iv).
(i) Melting point The melting point of component (F) according to the present invention is preferably 110°C or lower, more preferably 0 to 105°C, and even more preferably 0 to 100°C. Since the melting point of component (F) is within the above range, unmelted component (F) does not remain even at low kneading temperatures, and a conveyor belt with especially low molding shrinkage and excellent wear resistance can be obtained. .
The melting point of component (F) according to the present invention can be measured by the method described in JIS K 7121.

(ii) Density The density of component (F) according to the present invention is preferably 840 to 920 kg/m ³ , more preferably 850 to 915 kg/m ³ , and still more preferably 860 to 915 kg/m ³ . When the density is within the above range, a conveyor belt with low molding shrinkage and excellent strength and wear resistance can be obtained.
The density of component (F) according to the present invention can be measured by the method described in ASTM D1505.

(iii) MFR
The MFR of component (F) according to the present invention at 190°C and 2.16 kg is preferably 0.1 to 50 g/10 min, more preferably 0.2 to 30.0 g/10 min, and even more preferably 0 .3 to 10g/10min. When the MFR is within the above range, it is possible to obtain a copolymer composition for a conveyor belt that has a small mold shrinkage rate and is excellent in processability.
The MFR of component (F) according to the present invention can be measured by the method described in ASTM D1238.

(iv) Mw/Mn
Component (F) according to the present invention preferably has a ratio Mw/Mn of weight average molecular weight Mw to number average molecular weight Mn determined by GPC analysis in the range of 1.5 to 10.0.
The weight average molecular weight (Mw) of the component (F) according to the present invention determined by gel permeation chromatography (GPC) is preferably 10,000 to 500,000, more preferably 20,000 to 300, 000, more preferably in the range of 20,000 to 200,000.

The weight average molecular weight (Mn) of component (F) according to the present invention determined by GPC is preferably 1,000 to 250,000, more preferably 2,000 to 150,000, even more preferably 2 ,000 to 100,000.
Furthermore, component (F) according to the present invention is preferably solid at temperatures from room temperature to about 100°C, preferably around 90°C.

When the weight average molecular weight of component (F) according to the present invention is within the above range, a conveyor belt with a small molding shrinkage rate and excellent abrasion resistance can be obtained. Further, since the low molecular weight component is small, it is difficult for the low molecular weight component to volatilize or stand out in the resulting conveyor belt, which is preferable.

Specifically, the Mw, Mn, and Mw/Mn of the component (F) according to the present invention can be measured by the same method as the method for measuring the molecular weight of the copolymer (S) described in the following examples.
Component (F) according to the present invention can be produced by copolymerizing ethylene and α-olefin by a conventionally known method using, for example, a vanadium catalyst, a Ziegler-Natta catalyst, or a metallocene catalyst. . A method of synthesis using a metallocene catalyst is preferred from the viewpoint of easily obtaining a copolymer that satisfies the above-mentioned physical properties. More preferred is a synthesis method using a catalyst containing a compound or the like or a catalyst consisting of a metallocene compound and an organoaluminumoxy compound or an ionizable ionic compound described in JP-A-9-40586.

《Modified ethylene/α-olefin copolymer (K)》
A modified ethylene/α-olefin copolymer (K) which is one of the components contained in the copolymer composition for conveyor belts of the present invention [hereinafter may be abbreviated as "component (K)". ] is a polymer obtained by grafting an ethylene/α-olefin copolymer with an unsaturated carboxylic acid or a derivative thereof.

In component (K) according to the present invention, the grafting amount of the unsaturated carboxylic acid or its derivative is usually 0.1 to 10% by mass, preferably 1 to 10% by mass based on 100% by mass of component (K). %, more preferably 2 to 9% by mass.
Component (K) according to the present invention preferably ^has a density of 860 kg/m ³ or more and less than 880 kg/m 3 , more preferably 860 to 875 kg/m ³ , and even more preferably 865 to 875 kg/m ³ . When the density of component (K) is within the above range, the belt conveyor obtained from the copolymer composition of the present invention has excellent wear resistance.

Component (K) according to the present invention has a melting point of 20°C or more and less than 60°C as measured by differential scanning calorimetry (DSC), or a peak indicating the melting point is not observed by differential scanning calorimetry (DSC). is preferred. When component (K) satisfies this condition, it has excellent dispersibility in copolymer (A) during kneading and molding. When a peak indicating a melting point is observed by differential scanning calorimetry (DSC), the melting point is more preferably 30°C or more and less than 60°C, and even more preferably 40°C or more and less than 60°C.

The unsaturated carboxylic acids and/or derivatives thereof according to the present invention include unsaturated compounds having one or more carboxylic acid groups, esters of compounds having carboxylic acid groups and alkyl alcohol, or having one or more carboxylic anhydride groups. Examples of the unsaturated group include a vinyl group, a vinylene group, and an unsaturated cyclic hydrocarbon group. Specific compounds include, for example, acrylic acid, maleic acid, fumaric acid, tetrahydrophthalic acid, itaconic acid, citraconic acid, crotonic acid, isocrotonic acid, nadic acid [trademark] (endocys-bicyclo[2.2.1] or derivatives thereof, such as acid halides, amides, imides, anhydrides, esters, etc. Specific examples of such derivatives include maleyl chloride, maleimide, maleic anhydride, citraconic anhydride, monomethyl maleate, dimethyl maleate, glycidyl maleate, and the like. These unsaturated carboxylic acids and/or derivatives thereof can be used alone or in combination of two or more. Among these, unsaturated dicarboxylic acids or their acid anhydrides are preferred, and maleic acid, nadic acid, or their acid anhydrides are particularly preferred. The content of the unsaturated carboxylic acid and/or its derivative can be easily controlled, for example, by appropriately selecting the grafting conditions.

The method of grafting the graft monomer selected from unsaturated carboxylic acids and/or their derivatives onto the ethylene/α-olefin copolymer is not particularly limited, and conventionally known graft polymerization methods such as solution method and melt kneading method can be used. Can be adopted. For example, a method of melting an ethylene/α-olefin copolymer and adding a graft monomer thereto to cause a graft reaction, or a method of dissolving an ethylene/α-olefin copolymer in a solvent to form a solution, and then grafting the ethylene/α-olefin copolymer to a solution There are methods such as adding a monomer and causing a graft reaction.

In these methods, when graft polymerization is carried out in the presence of a radical initiator, the graft monomer such as the unsaturated carboxylic acid can be efficiently graft polymerized. In this case, the radical initiator is usually used in an amount of 0.001 to 1 part by weight per 100 parts by weight of the ethylene/α-olefin copolymer.

As such radical initiators, organic peroxides, azo compounds, etc. are used. As such radical initiators, organic peroxides, azo compounds, etc. are used. Examples of such radical initiators include benzoyl peroxide, dichlorobenzoyl peroxide, dicumyl peroxide, di-t-butyl peroxide, and 2,5-dimethyl-2,5-di(peroxide benzoate) hexyne. 3,1,4-bis(t-butylperoxyisopropyl)benzene, lauroylperoxide, t-butylperacetate, 2,5-dimethyl-2,5-di-(t-butylperoxide)hexyne-3,2,5 -dimethyl-2,5- di(t-butylperoxide)hexane, t-butyl perbenzoate, t-butyl perphenylacetate, t-butyl perisobutyrate, t-butyl per-sec-octoate, t-butyl perpi Barate, cumyl perpivalate, t-butyl perdiethyl acetate; azobisisobutyronitrile, dimethyl azoisobutyrate, and the like.
Among these, dicumyl peroxide, di-t-butyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexyne-3, 2,5-dimethyl-2,5-di(t Dialkyl peroxides such as -butylperoxy)hexane and 1,4-bis(t-butylperoxyisopropyl)benzene are preferably used.

The reaction temperature of the graft polymerization reaction using a radical initiator or the graft polymerization reaction conducted without using a radical initiator is usually set within the range of 60 to 350°C, preferably 150 to 300°C.

The ethylene/α-olefin copolymer (b) used for producing component (K) according to the present invention contains a unit derived from ethylene and an α-olefin having 3 or more carbon atoms, preferably 3 to 20 carbon atoms. It is a copolymer containing units derived from , and may be a random copolymer or a block copolymer.

Specifically, the α-olefins include propylene, 1-butene, 4-methyl-1-pentene-1, 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene. , 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-nonadecene, 1-eicosene, 9-methyl-1-decene, 11-methyl-1-dodecene and 12 -ethyl-1-tetradecene and the like. Among these, propylene, 1-butene, 4-methyl-1-pentene, 1-hexene and 1-octene are preferred, with propylene being particularly preferred. These α-olefins may be used alone or in combination of two or more.
The content of structural units derived from ethylene in the ethylene/α-olefin copolymer (b) according to the present invention is usually 50.0 mol based on the total structural units contained in the ethylene/α-olefin copolymer. % or more and less than 100 mol%, preferably 80.0 to 99.5 mol%, more preferably 90.0 to 99.0 mol%.
The density of the ethylene/α-olefin copolymer (b) according to the present invention is such that the density of the graft-modified ethylene/α-olefin copolymer (B) obtained by graft-modifying this is within the above range. The density is preferably 850 to 880 kg/m ³ , more preferably 855 to 875 kg/m ³ .
Regarding the melting point of the ethylene/α-olefin copolymer (b) according to the present invention, the melting point of the graft-modified ethylene/α-olefin copolymer [component (K)] obtained by graft modification thereof satisfies the above-mentioned conditions. Specifically, the melting point measured by differential scanning calorimetry (DSC) is 20 to 70°C, or a peak indicating the melting point is observed by differential scanning calorimetry (DSC). More preferably, the melting point measured by differential scanning calorimetry (DSC) is 30 to 60°C, or no peak indicating the melting point is observed by differential scanning calorimetry (DSC).
The melt flow rate (MFR; ASTM D 1238, 190°C, 2.16 kg load) of the ethylene/α-olefin copolymer (b) according to the present invention is preferably 0.1 to 100 g/10 minutes, more preferably The rate is 0.2 to 50 g/10 minutes, more preferably 0.3 to 20 g/10 minutes.
By using component (K) whose density, ethylene content, and MFR are within the above ranges, it is possible to improve both wear resistance and heat aging resistance.

<Non-polar hydrocarbon oil (E)>
A non-polar hydrocarbon oil (E) which is one of the components contained in the copolymer composition for conveyor belts of the present invention [hereinafter may be abbreviated as "component (E)". ] preferably has a dynamic viscosity of 1 to 80,000 mm ² /s at 40°C.

Oils with a kinematic viscosity of less than 1 mm ² /s at 40° C. have a large amount of low molecular weight components that easily volatilize, and therefore may have poor heat resistance. On the other hand, if it exceeds 80,000 mm ² /s, the amount of high molecular weight components increases and the viscosity becomes insufficient, reducing the effect of improving processability.

As the component (E) according to the present invention, a component (E) consisting of an ethylene copolymer is particularly suitable because it has good compatibility with the component (S) according to the present invention.

Such a non-polar hydrocarbon oil made of an ethylene copolymer is a copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, and examples of the α-olefin include propylene, 1-butene, 1- Pentene, 4-methyl-1-pentene, 1-hexene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, Linear α-olefins such as 1-heptadecene, 1-octadecene, 1-nonadecene, 1-eicosene, 4-methyl-pentene, 8-methyl-1-nonene, 7-methyl-1-decene, 6-methyl -1-Undecene, 6,8-dimethyl-1-decene and other branched α-olefins can be mentioned, but linear α-olefins are preferred, and one or more of these are preferred. Used as needed. In addition, such an ethylene-based copolymer is particularly preferably a random copolymer, and generally contains 5 to 95 mol% of ethylene constitutional units and 95 to 5 mol% of α-olefin constitutional units. mol% (the total of ethylene and α-olefin is 100 mol%).

Further, such ethylene copolymers generally have a number average molecular weight (Mn) of 100 to 30,000, preferably 100 to 20,000.
When the number average molecular weight (Mn) is less than 100, the amount of easily volatile low molecular weight components increases, and there is a possibility that heat resistance may deteriorate. On the other hand, if the number average molecular weight (Mn) exceeds 30,000, the amount of high molecular weight components increases and the effect of improving processability decreases.

Furthermore, the content of unsaturated groups at the terminals of molecules in such ethylene copolymers is 10% or less, preferably 5% or less, and more preferably 1% or less.
Methods for producing these ethylene copolymers include JP-A-3-179005, JP-A-3-193796, JP-A-6-122718, JP-A-8-239414, and JP-A-10-087716. There is a method using a catalyst used in producing α-olefin polymers, as described in Japanese Patent Publication No. 2000-212194.

<Carbon black (G)>
Carbon black (G) is one of the components contained in the copolymer composition for conveyor belts of the present invention [hereinafter may be abbreviated as "component (G)". ] is a type of known rubber reinforcing agent that is blended into rubber compositions, and is an inorganic substance usually called carbon black.

Specifically, the carbon black (G) according to the present invention includes Asahi #55G, Asahi #60G, Asahi #60UG (manufactured by Asahi Carbon Co., Ltd.), Seast (V, SO, 116, 3, 6). , 9, SP, TA, etc.) (manufactured by Tokai Carbon Co., Ltd.), and these carbon blacks are surface-treated with a silane coupling agent or the like.

<Anti-aging agent (H)>
The anti-aging agent (H) is one of the components contained in the copolymer composition for conveyor belts of the present invention [hereinafter may be abbreviated as "component (H)". ] is a conventionally known anti-aging agent, such as an amine-based anti-aging agent, a phenol-based anti-aging agent, a sulfur-based anti-aging agent, etc.

Further, as anti-aging agents, aromatic secondary amine anti-aging agents such as phenylbutylamine and N,N-di-2-naphthyl-p-phenylene diamine; dibutylhydroxytoluene, tetrakis [methylene (3,5-di- Phenolic anti-aging agents such as t-butyl-4-hydroxy)hydrocinnamate]methane (trade name: Irganox 1010, manufactured by BASF); bis[2-methyl-4-(3-n-alkylthiopropionyloxy)- Thioether-based anti-aging agents such as 5-t-butylphenyl] sulfide; dithiocarbamate-based anti-aging agents such as nickel dibutyldithiocarbamate; 2-mercaptobenzoylimidazole (trade name: Sandant MB, manufactured by Sanshin Kagaku Kogyo Co., Ltd.) , 2-mercaptobenzimidazole, zinc salt of 2-mercaptobenzimidazole, dilaurylthiodipropionate, distearylthiodipropionate, and other sulfur-based anti-aging agents.
These anti-aging agents can be used alone or in combination of two or more.

<Organic peroxide crosslinking agent (J)>
Organic peroxide crosslinking agent (J), which is one of the components that may be included in the copolymer composition for conveyor belts of the present invention [hereinafter may be abbreviated as "component (J)". ] is a type 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-chlorobenzoylperoxide, 2,4- Examples include dichlorobenzoyl peroxide, tert-butyl peroxybenzoate, ert-butyl peroxyisopropyl carbonate, diacetyl peroxide, lauroyl peroxide, tert-butyl cumyl peroxide and the like.

Among these, 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-trimethyl Organic peroxide-based crosslinking agents such as cyclohexane and n-butyl-4,4-bis(tert-butylperoxy)valerate are preferred.

<Copolymer composition for conveyor belt>
The copolymer composition for conveyor belts of the present invention comprises the above ethylene/α-olefin/non-conjugated polyene copolymer (S), the above ethylene/α-olefin copolymer (F), the above modified ethylene/α-olefin A composition comprising the copolymer (K), the non-polar hydrocarbon oil (E), the carbon black (G) and the anti-aging agent (H), preferably further comprising the organic peroxide cross-linking agent (J). ).

The copolymer composition for conveyor belts of the present invention has excellent processability by containing the above-mentioned components, and the conveyor belt obtained from the copolymer composition for conveyor belts has good mechanical properties, heat aging resistance, and resistance to heat aging. Excellent abrasion resistance.

The copolymer composition for conveyor belts of the present invention preferably contains 95 to 5 parts by mass of the component (S), preferably 95 to 5 parts by mass, based on a total of 100 parts by mass of the component (S) and the component (F). contains 90 to 10 parts by weight, more preferably 80 to 20 parts by weight, the above component (F) in a range of 5 to 95 parts by weight, preferably 10 to 90, more preferably 20 to 80 parts by weight, and the above component) and the above component (F) in a total amount of 100 parts by mass, the above component (K) is 1 to 20 parts by mass, more preferably 2 to 10 parts by mass, and the above component (E) is 1 to 80 parts by mass. , more preferably 5 to 30 parts by weight, the above component (G) 5 to 120 parts by weight, even more preferably 10 to 100 parts by weight, and the above component (H) 0.1 to 20 parts by weight, even more preferably 0 .2 to 15 parts by mass, and when the copolymer composition for conveyor belts further contains the above component (J), 0.1 to 30 parts by mass, more preferably 0.2 to 25 parts by mass. Included in the range.

Depending on the purpose, the copolymer composition for conveyor belts may contain, in addition to the above-mentioned components, other additives such as crosslinking aids, softeners, anti-aging agents, processing aids, activators, It may contain at least one selected from heat stabilizers, weather stabilizers, antistatic agents, colorants, lubricants, thickeners, antifoam agents, foaming agents, and foaming aids. Also. Each additive may be used alone or in combination of two or more.

<Crosslinking aid>
Examples of crosslinking aids include sulfur; quinonedioxime crosslinking aids such as p-quinonedioxime; acrylic crosslinking aids such as ethylene glycol dimethacrylate and trimethylolpropane trimethacrylate; diallyl phthalate and triallyl isocyanurate. Allyl crosslinking aids such as; maleimide crosslinking aids; divinylbenzene; zinc oxide (for example, ZnO #1, zinc oxide 2 types (JIS standard (K-1410)), manufactured by Hakusuitec Co., Ltd.), magnesium oxide, Examples include metal oxides such as activated zinc white (for example, zinc oxide such as "META-Z102" (trade name; manufactured by Inoue Lime Industry Co., Ltd.)).

When using a crosslinking aid, the amount of the crosslinking aid in the copolymer composition for a conveyor belt is usually 0.5 to 10 mol, preferably 0.5 to 10 mol, per 1 mol of the organic peroxide crosslinking agent. The amount is 5 to 7 mol, more preferably 1 to 6 mol.

<Other softeners>
Other softeners include, for example, process oil, lubricating oil, paraffin oil, liquid paraffin, petroleum asphalt, petroleum softeners such as petrolatum; coal tar softeners such as coal tar; castor oil, linseed oil, rapeseed oil. , fatty oil-based softeners such as soybean oil and coconut oil; waxes such as beeswax and carnauba wax; naphthenic acid, pine oil, rosin or its derivatives; synthetic polymer substances such as terpene resin, petroleum resin, coumaron indene resin, etc. ; Ester softeners such as dioctyl phthalate and dioctyl adipate; Others include microcrystalline wax, liquid polybutadiene, modified liquid polybutadiene, hydrocarbon-based synthetic lubricating oil, tall oil, and sub(factice); Preferred are softeners, and process oils are particularly preferred.

When the copolymer composition for conveyor belts contains other softeners, the total blending amount of the non-polar hydrocarbon oil (E) and other softeners is equal to Component (S) and Component (F). ): generally 3 to 200 parts by weight, preferably 10 to 100 parts by weight, based on 100 parts by weight.

<Processing aid>
As the processing aid, a wide variety of processing aids that are generally blended into rubber can be used. Specific examples include ricinoleic acid, stearic acid, palmitic acid, lauric acid, barium stearate, zinc stearate, calcium stearate, zinc laurate, and esters. Among these, stearic acid is preferred.

When the copolymer composition for conveyor belts contains a processing aid, it is usually blended in an amount of 1 to 3 parts by mass based on the total amount of component (S) and component (F): 100 parts by mass. be able to. It is preferable that the blending amount of the processing aid is within the above range because it provides excellent processability such as kneading processability, extrusion processability, and injection moldability.
The processing aids may be used alone or in combination of two or more.

<Activator>
Examples of the activator include amines such as di-n-butylamine, dicyclohexylamine, and monoelanolamine; diethylene glycol, polyethylene glycol, lecithin, triaryl utmerate, and zinc compounds of aliphatic carboxylic acids or aromatic carboxylic acids. Activators; zinc peroxide preparations; tadecyltrimethylammonium bromide, synthetic hydrotalcites, special quaternary ammonium compounds.

When the copolymer composition for conveyor belts contains an activator, the amount of the activator is usually 0.2 parts per 100 parts by mass of the total amount of component (S) and component (F). ~10 parts by weight, preferably 0.3 to 5 parts by weight.

<Foaming agents and foaming aids>
The molded article formed using the copolymer composition for conveyor belts of the present invention may be a non-foamed article or a foamed article. When the conveyor belt is a foam, the copolymer composition for the conveyor belt preferably contains a foaming agent.

As the blowing agent, any commercially available blowing agent can be suitably used. Examples of such blowing agents include inorganic blowing agents such as sodium bicarbonate, sodium carbonate, ammonium bicarbonate, ammonium carbonate, and ammonium nitrite; N,N'-dinitrosoterephthalamide, N,N'-dinitrosoterephthalamide, Nitroso compounds such as pentamethylenetetramine; azo compounds such as azodicarbonamide, azobisisobutyronitrile, azocyclohexylnitrile, azodiaminobenzene, barium azodicarboxylate; benzenesulfonyl hydrazide, toluenesulfonylhydrazide, p, p'- Examples include sulfonyl hydrazide compounds such as oxybis(benzenesulfonylhydrazide) diphenylsulfone-3,3'-disulfonylhydrazide; azide compounds such as calcium azide, 4,4'-diphenyldisulfonyl azide, and para-toluene malphonyl azide. Among these, azo compounds, sulfonyl hydrazide compounds, and azide compounds are preferably used.

When the copolymer composition for conveyor belts contains a blowing agent, the amount of the blowing agent to be blended is appropriately selected depending on the performance required of the molded article produced from the copolymer composition. The total amount of (S) and component (F) is usually 0.5 to 30 parts by weight, preferably 1 to 20 parts by weight, based on 100 parts by weight.

Further, if necessary, a foaming aid may be used in combination with the foaming agent. Addition of a foaming aid is effective in controlling 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 derivatives thereof.

When the copolymer composition for a conveyor belt contains a foaming aid, the amount of the foaming aid added is usually 1 to 100 parts by mass, preferably 2 to 80 parts by mass, per 100 parts by mass of the foaming agent. Used as a percentage.

<Method for producing copolymer composition for conveyor belt>
The copolymer composition for conveyor belts of the present invention can be prepared using an internal mixer (internal mixer) such as a Banbury mixer, a kneader, or an intermix. K), the above component (E), the above component (G), and the above component (H), if necessary, a softener, a processing aid, a crosslinking aid, etc., at a temperature of 80 to 170°C for 2 to 20 minutes. Knead for a minute. Next, additives such as a crosslinking agent, a softener, a crosslinking aid, and a vulcanization accelerator are added to the obtained blend using rolls such as open rolls or a vulcanization accelerator, if necessary. It can be prepared by additionally mixing a crosslinking aid, kneading for 5 to 30 minutes at a roll temperature of 40 to 80°C, and then dispensing.

In addition, when the kneading temperature in internal mixers is low, the above-mentioned components (S), (F), (K), the above-mentioned components (E), (G), and (H), etc. Component (J) may be kneaded at the same time.

<Conveyor belt>
The conveyor belt of the present invention is manufactured using the copolymer composition for conveyor belts of the present invention, and its specific structure includes the following.
A conveyor belt whose core material is canvas and whose outer periphery is coated with a copolymer composition for conveyor belts.
A conveyor belt made by embedding a steel cord as a core material in a copolymer composition for conveyor belts.

The canvas is, for example, a canvas made of woven fabric of synthetic fibers such as nylon, vinylon, polyester, etc. The number of layers of canvas, the thickness of the copolymer composition for conveyor belt, the belt width, etc. are determined as appropriate depending on the purpose of use. However, the thickness of the copolymer composition for conveyor belt is usually about 1.5 to 20 mm.

The core material made of steel cord is made by twisting multiple wires with a diameter of about 0.2 to 0.4 mm to form a wire rope with a diameter of about 2.0 to 9.5 mm. Approximately 50 to 230 steel cords are arranged in parallel. The conveyor belt is generally used as a core material, and the total thickness of the conveyor belt is generally about 10 to 50 mm.

The conveyor belt of the present invention can be produced by interposing canvas or steel cord serving as a core material between uncrosslinked sheets formed from the copolymer composition for conveyor belts of the present invention, and crosslinking the conveyor belt by heating and pressing in accordance with a conventional method. It can be easily manufactured by The crosslinking conditions are usually 120 to 180°C, 10 to 50 kg/cm ² , and 10 to 90 minutes.

Hereinafter, the present invention will be explained in more detail based on Examples, but the present invention is not limited to these Examples. In the following description, "parts" indicate "parts by mass" unless otherwise specified.
EXAMPLES Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to these Examples at all.

In the Examples and Comparative Examples, the following copolymers were used.
(1) Ethylene/α-olefin/nonconjugated polyene copolymer (S)
[Composition of ethylene/α-olefin/non-conjugated polyene copolymer (S)]
The molar ratio of each structural unit and the mass fraction (mass %) of the ethylene/α-olefin/nonconjugated polyene copolymer (S) were determined by ¹³ C-NMR measurements. Measured values were measured using an ECX400P 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 a number of integrations of 8000 times. The ¹³ C-NMR spectrum of the polymer was obtained.

As the ethylene/α-olefin/nonconjugated polyene copolymer (S), the ethylene/propylene/vinylnorbornene copolymer (S-1) obtained in Production Example 1 was used.

[Production Example 1] Production of ethylene-propylene-vinylnorbornene copolymer (S-1) Ethylene, propylene, and 5-vinyl-2-norbornene were continuously produced using a 300 L polymerization vessel equipped with stirring blades. The polymerization reaction of (VNB) was carried out at 87°C. Using hexane (feed amount: 32.6 L/h) as the polymerization solvent, the ethylene feed amount was 3.6 kg/h, the propylene amount was 6.1 kg/h, the VNB feed amount was 290 g/h, and Hydrogen was continuously supplied to the polymerization vessel so that the amount of hydrogen fed was 6.3 NL/h. While maintaining the polymerization pressure at 1.6 MPaG and the polymerization temperature at 87°C, using di(p-tolyl)methylene(cyclopentadienyl)(octamethyloctahydrodibenzofluorenyl)zirconium dichloride as the main catalyst, the feed amount was It was continuously supplied to the polymerization vessel at a rate of 0.0015 mmol/h. In addition, (C ₆ H ₅ ) ₃ CB(C ₆ F ₅ ) ₄ was fed as a cocatalyst at a feed rate of 0.0075 mmol/h, and triisobutylaluminum (TIBA) was fed as an organic aluminum compound at a feed rate of 20 mmol/h. Each was continuously supplied to the polymerization vessel.

In this way, a solution containing 15.2% by weight of an ethylene-propylene-VNB copolymer formed from ethylene, propylene and VNB was obtained. A small amount of methanol was added to the polymerization reaction solution taken out from the bottom of the polymerization vessel to stop the polymerization reaction, and after separating the ethylene/propylene/VNB copolymer from the solvent by steam stripping treatment, the pressure was reduced at 80°C overnight. Dry.

Through the above operations, an ethylene-propylene-VNB copolymer (S-1) formed from ethylene, propylene and VNB was obtained at a rate of 4.7 kg/hour. The physical properties of the obtained copolymer (S-1) were measured by the method described above. The results are shown in Table 1.

(2) Ethylene/α-olefin copolymer (F)
(2-1) Ethylene/1-butene copolymer (F-1)
Density: 864 kg/m ³ , melting point <50° C., MFR: 3.6 g/10 min [manufactured by Mitsui Chemicals, trade name: ^TAFMERTM DF640].

(2-2) Ethylene/1-butene copolymer (F-2)
Density: 862 kg/m ³ , melting point <50° C., MFR: 0.5 g/10 min [manufactured by Mitsui Chemicals, trade name: ^TAFMERTM DF605].

(2-3) Ethylene-propylene copolymer (F-3) (description of Mitsui EPT0045)
Mooney viscosity (ML (1+4) 100°C): 40, ethylene content: 51% by weight [manufactured by Mitsui Chemicals, trade name: Mitsui EPT 0045].

(2-4) Modified ethylene copolymer (K-1) (maleic anhydride modified ethylene/1-butene copolymer)
Density: 873 kg/m ³ , MFR: 0.7 g/10 min [manufactured by Mitsui Chemicals, trade name ^{: TAFMERTM} MH7020].

(3) Non-polar hydrocarbon oil (E)
As component (E-1), an ethylene/α-olefin oligomer having a molecular weight (Mw) of 16,000 and a kinematic viscosity of >50,000: trade name Lucant LX900Z (manufactured by Mitsui Chemicals) was used.

[Physical properties of copolymer composition for conveyor belt]
[Mooney viscosity (ML(1+4)100℃)]
Mooney viscosity at 100°C (ML(1+4) 100°C) was measured at 100°C using a Mooney viscometer (Model SMV202, manufactured by Shimadzu Corporation) in accordance with JIS K6300.

<Physical properties of copolymer composition (crosslinked product) for conveyor belts>
[Modulus (MPa), tensile stress at break (MPa), tensile elongation at break (%)]
A No. 3 dumbbell test piece as described in JIS K 6251 (1993) was prepared by punching out the sheet, and using this test piece, the measurement temperature was 25°C, according to the method specified in JIS K6251 Section 3. A tensile test was conducted at a tensile speed of 500 mm/min, and the modulus at 100% extension (M100), modulus at 200% extension (M200), tensile stress at break (TB), and tensile elongation at break (EB) were measured. .

[Durometer A hardness]
In accordance with JIS K 6253, the hardness (type A durometer, HA) of the sheet was measured by using six 2 mm thick crosslinked sheets with smooth surfaces, stacking the flat parts to a thickness of about 12 mm. However, test pieces with foreign matter mixed in, bubbles, or scratches were not used. In addition, the dimensions of the measurement surface of the test piece were such that measurements could be made at a position where the indenter tip was 12 mm or more away from the end of the test piece.

[Heat aging resistance]
The sheet was subjected to a heat aging test in accordance with JIS K 6257, in which the sheet was held at 180° C. for 72 hours (hrs) and 168 hours (hrs). The hardness, tensile stress at break (MPa), and elongation at tensile break (%) of the sheet after the heat aging test are determined from the above [Hardness (Durometer-A)] item, the above [modulus, tensile stress at break, tensile break point It was measured in the same manner as in the item ``Elongation''.

AH (Duro-A) is determined from the difference in hardness before and after the heat aging test, and from the tensile stress at break (TB) and tensile elongation at break (EB) before and after the heat aging test, the value after the test relative to the value before the heat aging test is determined. The rates of change were determined as Ac(TB) and Ac(EB), respectively.

[DIN friction test (amount of wear)]
In accordance with JIS-K6264-2:2005, a disk-shaped test piece with a diameter of 16.0 ± 0.2 mm and a thickness of 6 mm was prepared by stacking three cross-linked sheets with a thickness of 2 mm, and the test piece was subjected to DIN abrasion. Using a testing machine, a drum with a diameter of 150.0 ± 0.2 mm and a length of 500 mm is rotated at a rate of 40 times/min, the load is 1 kgf, and the abrasion distance is 40.0 ± 0.2 m. DIN wear amount (unit: mg) was measured.

[Example 1]
In the first step, 50 parts by mass of the copolymer (S-1) obtained in Production Example 1 and ethylene/1-butene copolymer (F -1): 45 parts by weight and modified ethylene copolymer (K-1): 5 parts by weight were masticated for 1 minute, and then 5 parts by weight of zinc white (ZnO #1, manufactured by Hakusui Tech Co., Ltd.) was added to this. , carbon black (G-1) (Asahi #70, manufactured by Asahi Carbon Co., Ltd.) 50 parts by weight, non-polar hydrocarbon oil (E-1): 15 parts by weight, as anti-aging agent (H-1), 3 parts by mass of a phenolic antioxidant (trade name Irganox 1010, manufactured by BASF), 2 parts by mass of an imidazole antioxidant (trade name Sandant MB, manufactured by Sanshin Kagaku Kogyo Co., Ltd.) as the antioxidant (H-2) Parts by mass and 6 parts by mass of stearic acid were added and kneaded at 140°C for 2 minutes. Thereafter, the ram was raised and cleaned, and kneading was further performed for 1 minute, and the kneaded material was discharged at about 150° C. to obtain a first-stage blend.

Next, in the second step, the mixture obtained in the first step was rolled onto a 6-inch roll (manufactured by Nippon Roll Co., Ltd., the surface temperature of the front roll was 50°C, the surface temperature of the back roll was 50°C, the front roll The rotation speed of the rear roll is 16 rpm, and the rotation speed of the rear roll is 18 rpm. Add 3.3 parts by weight of PARKADOX 14-40 (trade name, manufactured by Kayaku Akzo) and 1.8 parts by weight of zinc dimethacrylate (Actor ZMA, manufactured by Kawaguchi Chemical Industry Co., Ltd.) as a crosslinking aid, and mix for 10 minutes. The mixture was kneaded to obtain an uncrosslinked copolymer composition for conveyor belts. Using this copolymer composition, its physical properties were evaluated.

This uncrosslinked conveyor belt copolymer composition was extruded into a sheet shape, and then pressed at 170° C. for 15 minutes using a 100-ton press molding machine 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 Table 2.

[Comparative example 1]
Copolymer (S-1), copolymer (F-1), and ethylene/1-butene copolymer (F-2) used in Example 1 were used without using copolymer (K-1). ) and 70 parts by weight of the ethylene-propylene copolymer (F-3), and the same procedure as in Example 1 was performed except that the amounts of other additives were as shown in Table 1. The physical properties of the obtained uncrosslinked conveyor belt copolymer composition and crosslinked sheet were measured. The results are shown in Table 2.

[Comparative example 2]
Example 1 except that a softener (SpectraSyn10, manufactured by ExxonMobil) was used instead of the modified ethylene copolymer (K-1) and non-polar hydrocarbon oil (E-1) used in Example 1. I did the same. The physical properties of the obtained uncrosslinked conveyor belt copolymer composition and crosslinked sheet were measured. The results are shown in Table 2.

Claims (7)

A copolymer composition for a conveyor belt, comprising the following components (S), (F), (K), (E), (G) and (H);
(S) Ethylene (A), α-olefin having 3 to 20 carbon atoms (B), and a total of two partial structures selected from the group consisting of the following general formulas (I) and (II) in the molecule. An ethylene/α-olefin/non-conjugated polyene copolymer that has a structural unit derived from the above-mentioned non-conjugated polyene (C) and satisfies the following requirements (i) to (v);
(F) an ethylene/α-olefin copolymer containing ethylene and an α-olefin having 3 to 20 carbon atoms;
(K) modified ethylene/α-olefin copolymer;
(E) non-polar hydrocarbon oil;
(G) carbon black;
(H) Anti-aging agent;
Ethylene/α-olefin/non-conjugated polyene copolymer (S);
(i) The molar ratio of ethylene/α-olefin is 40/60 to 99.9/0.1.
(ii) The weight fraction of the structural unit derived from the non-conjugated polyene (C) is 0.07% by weight to 10% by weight based on 100% by weight of the ethylene/α-olefin/non-conjugated polyene copolymer.
(iii) Weight average molecular weight (Mw) of the ethylene/α-olefin/non-conjugated polyene copolymer and the weight fraction of structural units derived from the non-conjugated polyene (C) (weight fraction of (C) (wt%) )) and the molecular weight of the non-conjugated polyene (C) (molecular weight of (C)) satisfy the following formula (1).
4.5≦Mw×weight fraction of (C)/100/molecular weight of (C)≦40...Formula (1)
(iv) Complex viscosity η ^* ₍ ω _=0.1) (Pa sec) at frequency ω = 0.1 rad/s obtained by linear viscoelasticity measurement (190°C) using a rheometer, and frequency ω = The ratio P (η ^* ₍ ω _=0.1) /η ^* ₍ ω ₌₁₀₀₎ ) to the complex viscosity η ^* ₍ ω ₌₁₀₀₎ (Pa・sec) at 100 rad/s, the limiting viscosity [η], and the above The weight fraction of the structural unit derived from the non-conjugated polyene (C) (the weight fraction of (C)) satisfies the following formula (2).
P/([η] ^2.9 )≦weight fraction of (C)×6...Formula (2)
(v) The number of long chain branches per 1000 carbon atoms (LCB _1000C ) obtained using 3D-GPC and the natural logarithm [Ln (Mw)] of the weight average molecular weight (Mw) are expressed by the following formula (3) satisfy.
LCB _1000C ≦1-0.07×Ln(Mw)...Formula (3) The copolymer composition for a conveyor belt according to claim 1, further comprising the following (J). (J) organic peroxide crosslinking agent; Claim 1 or 2, wherein the ethylene/α-olefin/nonconjugated polyene copolymer (S) has an intrinsic viscosity [η] of 0.1 to 5 dL/g and a weight average molecular weight (Mw) of 10,000 to 600,000. A copolymer composition for a conveyor belt as described in . The non-conjugated polyene (C) constituting the ethylene/α-olefin/non-conjugated polyene copolymer (S) is 5-vinyl-2-norbornene (VNB) according to any one of claims 1 to 3. Copolymer composition for conveyor belts. A non-conjugated polyene (D) in which the ethylene/α-olefin/non-conjugated polyene copolymer (S) further contains only one partial structure selected from the group consisting of formulas (I) and (II) in the molecule. The structural unit derived from is used in a weight fraction of 0% to 20% by weight (however, the sum of the weight fractions of (A), (B), (C), and (D) is 100% by weight). The copolymer composition for a conveyor belt according to any one of claims 1 to 4, which comprises:
(vi) Weight average molecular weight (Mw) of the ethylene/α-olefin/non-conjugated polyene copolymer and the weight fraction of the structural unit derived from the non-conjugated polyene (C) (weight fraction of (C) (wt%) )), the weight fraction of the structural unit derived from the conjugated polyene (D) (the weight fraction (weight %) of (D)), the molecular weight of the non-conjugated polyene (C) (the molecular weight of (C)), The molecular weight of the conjugated polyene (D) (the molecular weight of (D)) satisfies the following formula (4). ;
4.5≦Mw×{(weight fraction of (C)/100/molecular weight of (C))+(weight fraction of (D)/100/molecular weight of (D))}≦45...Formula ( 4) According to any one of claims 1 to 5, the non-conjugated polyene (D) constituting the ethylene/α-olefin/non-conjugated polyene copolymer (S) is 5-ethylidene-2-norbornene (ENB). A copolymer composition for a conveyor belt as described. A conveyor belt using the copolymer composition for conveyor belts according to any one of claims 1 to 6.