JP5961476B2 - Rubber composition for conveyor belt, conveyor belt and belt conveyor - Google Patents

Description

  The present invention relates to a rubber composition for a conveyor belt, a conveyor belt obtained using the rubber composition for a conveyor belt, and a belt conveyor equipped with the conveyor belt.

The belt conveyor is used as a means for conveying various kinds of luggage such as materials and foods. In recent years, large-sized ones have been used in order to increase the transportation amount and improve transportation efficiency, and those having a total length of several kilometers have also appeared. For this reason, higher durability is required and reduction in power consumption is required.
The belt (conveyor belt) to be mounted on the belt conveyor usually has a core body as a reinforcing material therein, and a cover rubber on the upper side of the core body (a surface that becomes an outer periphery when used as a conveyor belt). Hereinafter, the outer peripheral cover rubber is referred to. ] And cover rubber of the inner periphery (back surface when used for a conveyor belt, lower side) [hereinafter referred to as inner cover rubber. ]. The required physical properties are different between the outer peripheral cover rubber and the inner peripheral cover rubber located on the back surface thereof, and the inner peripheral cover rubber reduces not only tear resistance but also energy loss due to contact between the conveyor belt and a large number of rollers. That is, it is necessary to reduce power consumption by reducing the loss.
To date, rubber compositions for conveyor belts having excellent tear resistance include rubber compositions containing natural rubber (NR) and butadiene rubber (BR) or styrene butadiene rubber (SBR) in various combinations. (See Patent Documents 1 and 2). However, the rubber compositions described in Patent Documents 1 and 2 contain styrene butadiene rubber (SBR), so that the tear resistance is good, but the internal loss is large, so the energy saving performance is It was scarce.
Therefore, the present inventor has (A) 100 parts by mass of a diene polymer, and (B) a carbon black (b-) having a nitrogen adsorption specific surface area of 60 to 100 m ² / g and a dibutyl phthalate (DBP) oil absorption of less than 110 ml / 100 g. 1) and a rubber composition for conveyor belts containing 25 to 55 parts by mass of carbon black (b-2) containing a nitrogen adsorption specific surface area of less than 60 m ² / g and a DBP oil absorption of 110 ml / 100 g or more. Was developed, and it was found that the rubber composition can achieve both energy saving and durability, and a patent application (Japanese Patent Application No. 2011-271378) was filed first.

JP-A-11-139523 JP 2004-346220 A

However, the rubber composition for conveyor belts described in Japanese Patent Application No. 2011-271378 certainly has a high level of balance between energy saving and durability compared to conventional rubber compositions for conveyor belts. It has been found that durability may not always be high. Therefore, development of the rubber composition for conveyor belts which is excellent in energy saving property and has durability stably at a high level is desired.
Therefore, the object of the present invention is to provide a rubber composition for a conveyor belt that can achieve both energy saving and extremely high durability, and to provide a conveyor belt that has both energy saving and extremely high durability. Is to provide a belt conveyor equipped with the conveyor belt.

  As a result of intensive studies to solve the above problems, the present inventors can solve the above problems as long as the rubber composition contains a diene polymer and two specific carbon blacks in a specific ratio. I found out. The present invention has been completed based on such findings.

That is, the present invention relates to the following [1] to [6].
[1] (A) 100 parts by mass of a diene polymer,
(B) the nitrogen adsorption specific surface area 60~100m ² / g and dibutyl phthalate oil absorption of 110 ml / 100 g than the carbon black (b-1) and a nitrogen adsorption specific than surface area 60 m ² / g and dibutyl phthalate oil absorption of 110 ml / 100 g or more Carbon black (b-2) containing 25 to 55 parts by mass of carbon black,
(C) The rubber composition for conveyor belts containing 1-15 mass parts of silicas, and (D) 0.1-1.5 mass parts of silane coupling agents.
[2] The rubber composition for a conveyor belt according to the above [1], wherein the component (A) comprises at least one 15-65% by mass selected from natural rubber and isoprene rubber and 85-35% by mass of butadiene rubber. .
[3] The rubber composition for a conveyor belt according to the above [2], wherein the cis-1,4 bond content of the butadiene rubber is 90% or more.
[4] The rubber composition for conveyor belts according to any one of the above [1] to [3], further comprising 0.1 to 10 parts by mass of an antioxidant.
[5] A conveyor belt obtained using the rubber composition according to [1].
[6] A belt conveyor equipped with the conveyor belt according to [5].

  According to the present invention, there are provided a rubber composition for a conveyor belt that achieves both energy saving and extremely high durability, a conveyor belt having both energy saving and extremely high durability, and a belt conveyor equipped with the conveyor belt. Can do. In particular, the rubber composition for conveyor belts of the present invention has a great merit in that it has extremely high durability stably regardless of subtle differences in production conditions and kneading conditions.

[Rubber composition for conveyor belt]
The rubber composition for conveyor belts of the present invention,
(A) 100 parts by mass of a diene polymer,
(B) Carbon black (b-1) having a nitrogen adsorption specific surface area of 60 to 100 m ² / g and dibutyl phthalate (DBP) oil absorption of less than 110 ml / 100 g; a nitrogen adsorption specific surface area of less than 60 m ² / g and a DBP oil absorption of 110 ml / 25 to 55 parts by mass of carbon black containing 100 g or more of carbon black (b-2),
(C) 1 to 15 parts by mass of silica, and (D) 0.1 to 1.5 parts by mass of a silane coupling agent, and a conveyor belt obtained using the rubber composition is energy-saving. Combined with extremely high durability.
Hereinafter, the component of the rubber composition for conveyor belts of this invention is demonstrated.

((A) Diene polymer)
Examples of the diene polymer as the component (A) include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), ethylene-propylene rubber (EPR), and ethylene. -Propylene-diene rubber (EPDM), butyl rubber (IIR), halogenated butyl rubber, chloroprene rubber and the like. These may be used individually by 1 type and may use 2 or more types together. In the present invention, from the viewpoint of achieving both energy saving and durability, it is preferable to use two or more types together, more preferably at least two types selected from natural rubber, isoprene rubber and butadiene rubber are used in combination. It is more preferable to use butadiene rubber in combination with at least one selected from rubber and isoprene rubber, and it is particularly preferable to use butadiene rubber in combination with natural rubber or isoprene rubber.
In addition, the component (A) is preferably composed of at least one type selected from natural rubber and isoprene rubber, 15 to 65% by mass and butadiene rubber 85 to 35% by mass from the viewpoint of achieving both energy saving and durability. More preferably, it consists of 20 to 60% by mass of at least one selected from natural rubber and isoprene rubber and 80 to 40% by mass of butadiene rubber.
The butadiene rubber is preferably a high-cis butadiene rubber from the viewpoint of achieving both energy saving and durability. The high cis butadiene rubber is a high cis butadiene rubber having a cis-1,4 bond content in a 1,3-butadiene unit of 90% or more and less than 98% as measured by FT-IR. The cis-1,4 bond content in the 1,3-butadiene unit of the high cis-butadiene rubber is preferably 95% or more and less than 98%. There is no restriction | limiting in particular in the manufacturing method of high cis-butadiene rubber, It can manufacture by a well-known method. For example, it can be produced by polymerizing butadiene using a neodymium catalyst. High-cis butadiene rubber is commercially available, and for example, “BR01” and “T700” manufactured by JSR Corporation can also be used.

((B) Carbon black)
The carbon black (B) is a carbon black (b-1) having a nitrogen adsorption specific surface area of 60 to 100 m ² / g and a DBP oil absorption of less than 110 ml / 100 g from the viewpoint of achieving both energy saving and durability. Carbon black (b-2) having a nitrogen adsorption specific surface area of less than 60 m ² / g and a DBP oil absorption of 110 ml / 100 g or more is used in combination.
The carbon black as the component (b-1) is preferably a nitrogen adsorption specific surface area of 70 to 90 m ² / g and a DBP oil absorption of 60 to 108 ml / 100 g from the viewpoint of durability, and a nitrogen adsorption specific surface area of 70 to 90 m. ² / g and DBP oil absorption of 65 to 108 ml / 100 g are more preferable. In addition, although only the said (b-1) component has an effect which improves durability, it exists in the tendency for energy saving property to become low. (B-1) A component may be used individually by 1 type and may use 2 or more types together.
The carbon black (b-2) is preferably a nitrogen adsorption specific surface area of 30 to 55 m ² / g and a DBP oil absorption of 110 to 140 ml / 100 g from the viewpoint of energy saving, and a nitrogen adsorption specific surface area of 35 to 50 m. ² / g and DBP oil absorption of 115 to 130 ml / 100 g are more preferable. In addition, although only the said (b-2) component has an effect which improves energy saving property, it exists in the tendency for durability to become low. (B-2) A component may be used individually by 1 type and may use 2 or more types together.
In the present specification, the nitrogen adsorption specific surface area and the DBP oil absorption of carbon black are values measured according to JIS K 6217 (1997).
The content ratio [(b-1) :( b-2)] of the component (b-1) and the component (b-2) is a mass ratio, preferably 10:90 to 90:10, more preferably 15: It is 85-90: 10, More preferably, it is 20: 80-80: 20, More preferably, it is 40: 60-80: 20, Most preferably, it is 50: 50-70: 30. If it is said content ratio, both energy-saving property and durability can be improved.
Carbon black may be produced by any method such as the furnace method, channel method, acetylene method, thermal method, etc., and those produced by the furnace method are particularly preferred. Specific examples of carbon black include standard varieties such as SAF, ISAF, HAF, FEF, GPF, SRF (hereinafter, rubber furnace), MT carbon black (pyrolytic carbon), and the like. Among these, carbon black that meets the above-mentioned regulations may be appropriately selected and used. Among these, the furnace for rubber is preferable, and HAF and FEF are more preferable.

The rubber composition for conveyor belts of the present invention also includes a component (B) [carbon black other than the components (b-1) and (b-2) (hereinafter referred to as carbon black (b-3)). ] Is 25-55 mass parts with respect to 100 mass parts of (A) component. If it is less than 25 parts by mass, the durability is poor. On the other hand, when it exceeds 55 parts by mass, the energy saving property becomes insufficient. From the same viewpoint, the content of the component (B) is preferably 25 to 50 parts by mass, more preferably 30 to 50 parts by mass, and further preferably 35 to 50 parts by mass with respect to 100 parts by mass of the component (A). It is.
In the component (B), the total content ratio of the component (b-1) and the component (b-2) is preferably 85% by mass or more, more preferably 90% by mass or more, further preferably 95% by mass or more, particularly preferably. Is substantially 100% by mass.
The rubber composition for conveyor belts of the present invention contains carbon black (b-3) not corresponding to the above components (b-1) and (b-2) as long as the effects of the present invention are not significantly impaired. May be. When the carbon black (b-3) is contained, the content is preferably such that the total content ratio of the components (b-1) and (b-2) in the component (B) is within the above range. .

((C) Silica)
In the present invention, by containing silica as the component (C) in the rubber composition, while maintaining the energy saving property of the rubber composition containing the component (A) and the component (B) at a specific blending ratio, The effect of further improving the good durability can be obtained. By blending the component (C), a rubber composition having a very high durability can be obtained stably regardless of the blending order, blending method, kneading conditions and the like. Although the exact reason why such an effect appears is unknown, it is presumed as follows. In other words, silica does not have the ability to convert the energy generated by the small deformation strain necessary for the conveyor belt into heat, so that energy saving is maintained or not significantly reduced, but the energy generated by the large deformation strain is converted into heat. It has the ability to convert and dissipate, so it is speculated that durability will be greatly increased.
Any commercially available silica can be used. Of these, wet silica, dry silica, and colloidal silica are preferably used, and wet silica is particularly preferably used.
The BET specific surface area (measured according to ISO 5794/1) of silica is preferably 40 to 350 m ² / g. Silica having a BET surface area in this range has good dispersibility in the rubber component, and is excellent in durability improvement effect of the rubber composition while maintaining good energy saving. From this viewpoint, the BET surface area of silica is more preferably 80 to 350 m ² / g, further preferably 120 to 350 m ² / g, and particularly preferably 150 to 300 m ² / g.
Examples of such silica include Tosoh Silica Co., Ltd., trade name “Nipsil AQ” (BET specific surface area = 220 m ² / g), “Nipsil KQ”, Degussa Corporation, trade name “Ultra Gil VN3” (BET ratio). There are commercially available products such as surface area = 175 m ² / g), which can be used.
Silica may be used alone or in combination of two or more.
In the rubber composition for conveyor belts of the present invention, the content of silica as component (C) is 1 to 15 parts by mass with respect to 100 parts by mass of component (A). If the amount is less than 1 part by mass, the effect of improving the durability is poor. On the other hand, if the amount exceeds 15 parts by mass, the composition becomes stiff and difficult to form into a sheet, that is, the moldability is lowered. From this viewpoint, the amount is preferably 1 to 10 parts by mass, more preferably 2 to 8 parts by mass, and further preferably 2 to 6 parts by mass with respect to 100 parts by mass of the component (A).
Moreover, although the total content of (B) component and (C) component will be 26-70 mass parts with respect to 100 mass parts of (A) component, from a viewpoint of making energy saving and extremely high durability compatible, Preferably it is 30-60 mass parts, More preferably, it is 35-55 mass parts, More preferably, it is 40-50 mass parts.

((D) Silane coupling agent)
In the rubber composition of the present invention, a silane coupling agent is contained as the component (D) in order to maintain the energy saving property that tends to be lowered by the component (C) at a high level.
The silane coupling agent is preferably at least one selected from the group consisting of compounds represented by the following general formulas (I) to (IV). By using such a silane coupling agent, the rubber composition of the present invention is further excellent in workability at the time of rubber processing and further improves the durability.
Hereinafter, the following general formulas (I) to (IV) will be described in order.

式中、複数のＲ¹は同一でも異なっていてもよく、各々炭素数１〜８の直鎖、環状もしくは分枝のアルキル基又は炭素数２〜８の直鎖もしくは分枝のアルコキシアルキル基を表す。複数のＲ²は同一でも異なっていてもよく、各々炭素数１〜８の直鎖、環状もしくは分枝のアルキル基を表す。複数のＲ³は同一でも異なっていてもよく、各々炭素数１〜８の直鎖もしくは分枝のアルキレン基を表す。ａは平均値として２〜６であり、ｐ及びｒは同一でも異なっていてもよく、各々平均値として０〜３である。但し、ｐ及びｒの双方が３であることはない。

In the formula, a plurality of R ^{1 s} may be the same or different, and each represents a linear, cyclic or branched alkyl group having 1 to 8 carbon atoms or a linear or branched alkoxyalkyl group having 2 to 8 carbon atoms. Represent. A plurality of R ² may be the same or different and each represents a linear, cyclic or branched alkyl group having 1 to 8 carbon atoms. Several R < ³ > may be same or different and each represents a C1-C8 linear or branched alkylene group. a is an average value of 2 to 6, and p and r may be the same or different, and are each an average value of 0 to 3. However, both p and r are not 3.

  Specific examples of the silane coupling agent represented by the general formula (I) include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-trimethoxysilylpropyl) tetrasulfide, and bis (3-methyldimethoxysilylpropyl). ) Tetrasulfide, bis (2-triethoxysilylethyl) tetrasulfide, bis (3-triethoxysilylpropyl) disulfide, bis (3-trimethoxysilylpropyl) disulfide, bis (3-methyldimethoxysilylpropyl) disulfide, bis (2-triethoxysilylethyl) disulfide, bis (3-triethoxysilylpropyl) trisulfide, bis (3-trimethoxysilylpropyl) trisulfide, bis (3-methyldimethoxysilylpropyl) trisulfide, (2-triethoxysilylethyl) trisulfide, bis (3-monoethoxydimethylsilylpropyl) tetrasulfide, bis (3-monoethoxydimethylsilylpropyl) trisulfide, bis (3-monoethoxydimethylsilylpropyl) disulfide, Bis (3-monomethoxydimethylsilylpropyl) tetrasulfide, bis (3-monomethoxydimethylsilylpropyl) trisulfide, bis (3-monomethoxydimethylsilylpropyl) disulfide, bis (2-monoethoxydimethylsilylethyl) tetrasulfide Bis (2-monoethoxydimethylsilylethyl) trisulfide, bis (2-monoethoxydimethylsilylethyl) disulfide, and the like.

式中、Ｒ⁴は、−Ｃｌ、−Ｂｒ、Ｒ⁹Ｏ−、Ｒ⁹Ｃ（＝Ｏ）Ｏ−、Ｒ⁹Ｒ¹⁰Ｃ＝ＮＯ−、Ｒ⁹Ｒ¹⁰ＣＮＯ−、Ｒ⁹Ｒ¹⁰Ｎ−及び−（ＯＳｉＲ⁹Ｒ¹⁰）_h（ＯＳｉＲ⁹Ｒ¹⁰Ｒ¹¹）から選択される一価の基（Ｒ⁹、Ｒ¹⁰及びＲ¹¹は、それぞれ独立して、水素原子又は炭素数１〜１８の一価の炭化水素基であり、それぞれ同一でもよいし、異なっていてもよい。また、ｈは、平均値として１〜４である。）であり、Ｒ⁵はＲ⁴、水素原子又は炭素数１〜１８の一価の炭化水素基であり、Ｒ⁶は、Ｒ⁴、Ｒ⁵、水素原子又は−[Ｏ（Ｒ¹²Ｏ）_j]_0.5 −基（Ｒ¹²は炭素数１〜１８のアルキレン基である。ｊは、１〜４の整数である。）であり、Ｒ⁷は、炭素数１〜１８の二価の炭化水素基であり、Ｒ⁸は、炭素数１〜１８の一価の炭化水素基である。また、ｘ、ｙ及びｚは、ｘ＋ｙ＋２ｚ＝３、０≦ｘ≦３、０≦ｙ≦２、０≦ｚ≦１の関係を満たす数である。

Wherein, R ^{4 is, -Cl, -Br, R 9 O-} , R 9 C (= O) O-, R 9 R 10 C = NO-, R 9 R 10 CNO-, R 9 R 10 N- And-(OSiR ⁹ R ¹⁰ ) _h (OSiR ⁹ R ¹⁰ R ¹¹ ) each independently represents a monovalent group (R ⁹ , R ^{10, or} R ¹¹⁾ is independently a hydrogen atom or a C 1-18 carbon atom. A monovalent hydrocarbon group, which may be the same or different, and h is 1 to 4 on average, and R ⁵ is R ⁴ , a hydrogen atom or a carbon number. 1 to 18 monovalent hydrocarbon groups, R ⁶ is R ⁴ , R ⁵ , a hydrogen atom or — [O (R ¹² O) _j ] _0.5 — group (R ¹² is an alkylene having 1 to 18 carbon atoms). J is an integer of 1 to 4), R ⁷ is a divalent hydrocarbon group having 1 to 18 carbon atoms, and R ⁸ is a monovalent group having 1 to 18 carbon atoms. It is a hydrocarbon group. X, y, and z are numbers satisfying the relationship of x + y + 2z = 3, 0 ≦ x ≦ 3, 0 ≦ y ≦ 2, and 0 ≦ z ≦ 1.

In the general formula (II), R ^{8 to} R ¹¹ may be the same or different from each other, and are each a straight-chain, cyclic or branched alkyl group, alkenyl group, aryl group and aralkyl group having 1 to 18 carbon atoms. A group selected from the group consisting of
When R ⁵ is a monovalent hydrocarbon group having 1 to 18 carbon atoms, it is a group selected from the group consisting of a linear, cyclic or branched alkyl group, alkenyl group, aryl group and aralkyl group. Preferably there is. R ¹² is preferably a linear, cyclic or branched alkylene group, particularly preferably a linear one. Examples of the divalent hydrocarbon group having 1 to 18 carbon atoms represented by R ⁷ include an alkylene group having 1 to 18 carbon atoms, an alkenylene group having 2 to 18 carbon atoms, a cycloalkylene group having 5 to 18 carbon atoms, and 6 carbon atoms. A cycloalkylalkylene group having 18 to 18 carbon atoms, an arylene group having 6 to 18 carbon atoms, and an aralkylene group having 7 to 18 carbon atoms. The alkylene group and alkenylene group may be linear or branched, and the cycloalkylene group, cycloalkylalkylene group, arylene group, and aralkylene group have a substituent such as a lower alkyl group on the ring. You may have. R ⁷ is preferably an alkylene group having 1 to 6 carbon atoms, particularly preferably a linear alkylene group such as a methylene group, an ethylene group, a trimethylene group, a tetramethylene group, a pentamethylene group, or a hexamethylene group. it can.

Specific examples of the monovalent hydrocarbon group having 1 to 18 carbon atoms of R ⁵ and R ^{8 to} R ¹¹ in the general formula (II) include methyl group, ethyl group, n-propyl group, isopropyl group, n- Butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl, octyl, decyl, dodecyl, cyclopentyl, cyclohexyl, vinyl, propenyl, allyl, hexenyl, octenyl Group, cyclopentenyl group, cyclohexenyl group, phenyl group, tolyl group, xylyl group, naphthyl group, benzyl group, phenethyl group, naphthylmethyl group and the like.
Examples of R ¹² in the general formula (II) include methylene group, ethylene group, trimethylene group, tetramethylene group, pentamethylene group, hexamethylene group, octamethylene group, decamethylene group, dodecamethylene group and the like.

  Specific examples of the silane coupling agent represented by the general formula (II) include 3-hexanoylthiopropyltriethoxysilane, 3-octanoylthiopropyltriethoxysilane, 3-decanoylthiopropyltriethoxysilane, 3-lauroylthiopropyltriethoxysilane, 2-hexanoylthioethyltriethoxysilane, 2-octanoylthioethyltriethoxysilane, 2-decanoylthioethyltriethoxysilane, 2-lauroylthioethyltriethoxysilane, 3- Hexanoylthiopropyltrimethoxysilane, 3-octanoylthiopropyltrimethoxysilane, 3-decanoylthiopropyltrimethoxysilane, 3-lauroylthiopropyltrimethoxysilane, 2-hexanoylthioethyltrimethoxysilane, - it can be exemplified octanoylthiopropyl ethyltrimethoxysilane, 2- deca Neu thio ethyltrimethoxysilane, 2-lauroyl thio ethyl trimethoxysilane. Among these, 3-octanoylthiopropyltriethoxysilane (manufactured by General Electric Silicones, “NXT silane”) is particularly preferable.

式中、Ｒ¹³は、炭素数１〜８の直鎖、環状もしくは分枝のアルキル基又は炭素数２〜８の直鎖もしくは分枝のアルコキシアルキル基であり、複数のＲ¹³は、同一でも異なっていてもよい。Ｒ¹⁴は、炭素数１〜８の直鎖、環状もしくは分枝のアルキル基であり、複数のＲ¹⁴は、同一でも異なっていてもよい。Ｒ¹⁵は、炭素数１〜８の直鎖もしくは分枝のアルキレン基であり、複数のＲ¹⁵は、同一でも異なっていてもよい。Ｒ¹⁶は、一般式（−Ｓ−Ｒ¹⁷−Ｓ−）、（−Ｒ¹⁸−Ｓ_m1−Ｒ¹⁹−）及び（−Ｒ²⁰−Ｓ_m2−Ｒ²¹−Ｓ_m3−Ｒ²²−）のいずれかの二価の基（Ｒ¹⁷〜Ｒ²²は同一でも異なっていてもよく、各々炭素数１〜２０の二価の炭化水素基、二価の芳香族基又は硫黄及び酸素以外のヘテロ元素を含む二価の有機基であり、ｍ１、ｍ２、ｍ３は同一でも異なっていてもよく、各々平均値として１以上４未満である。）である。
また、ｋは、平均値として１〜６であり、ｓ及びｔは、それぞれ独立して、平均値として０〜３であり、それぞれ同一でも異なっていてもよい。但し、ｓ及びｔの双方が３であることはない。

In the formula, R ¹³ is a linear, cyclic or branched alkyl group having 1 to 8 carbon atoms or a linear or branched alkoxyalkyl group having 2 to 8 carbon atoms, and a plurality of R ¹³ may be the same. May be different. R ¹⁴ is a linear, cyclic or branched alkyl group having 1 to 8 carbon atoms, and a plurality of R ¹⁴ may be the same or different. R ¹⁵ is a linear or branched alkylene group having 1 to 8 carbon atoms, and a plurality of R ¹⁵ may be the same or different. R ¹⁶ is any one of the general formulas (—S—R ¹⁷ —S—), (—R ¹⁸ —S _m1 —R ¹⁹ —) and (—R ²⁰ —S _m2 —R ²¹ —S _m3 —R ²² —). These divalent groups (R ^{17 to} R ²² may be the same or different and each represents a divalent hydrocarbon group having 1 to 20 carbon atoms, a divalent aromatic group, or a hetero element other than sulfur and oxygen. And m1, m2, and m3 may be the same or different, and each has an average value of 1 or more and less than 4.
Further, k is 1 to 6 as an average value, and s and t are independently 0 to 3 as an average value, and may be the same or different. However, both s and t are not 3.

As a specific example of the silane coupling agent represented by the general formula (III),
Average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S 2 - (CH 2) 6 -S 2 - (CH 2) 3 -Si (OCH 2 CH 3) 3,
Average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S 2 - (CH 2) 10 -S 2 - (CH 2) 3 -Si (OCH 2 CH 3) 3,
Average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S 3 - (CH 2) 6 -S 3 - (CH 2) 3 -Si (OCH 2 CH 3) 3,
Average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S 4 - (CH 2) 6 -S 4 - (CH 2) 3 -Si (OCH 2 CH 3) 3,
Average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S- (CH 2) 6 -S 2 - (CH 2) 6 -S- (CH 2) 3 -Si (OCH 2 CH 3 ₃
Average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S- (CH 2) 6 -S 2.5 - (CH 2) 6 -S- (CH 2) 3 -Si (OCH 2 CH 3 ) _3,
Average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S- (CH 2) 6 -S 3 - (CH 2) 6 -S- (CH 2) 3 -Si (OCH 2 CH 3 ₃
Average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S- (CH 2) 6 -S 4 - (CH 2) 6 -S- (CH 2) 3 -Si (OCH 2 CH 3 ₃
Average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S- (CH 2) 10 -S 2 - (CH 2) 10 -S- (CH 2) 3 -Si (OCH 2 CH 3 ₃
Average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S 4 - (CH 2) 6 -S 4 - (CH 2) 6 -S 4 - (CH 2) 3 -Si (OCH 2 CH _{3) 3,}
Average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S 2 - (CH 2) 6 -S 2 - (CH 2) 6 -S 2 - (CH 2) 3 -Si (OCH 2 CH _{3) 3,}
Average composition formula _{(CH 3 CH 2 O) 3} Si- (CH 2) 3 -S- (CH 2) 6 -S 2 - (CH 2) 6 -S 2 - (CH 2) 6 -S- (CH 2 ) ₃ -Si (OCH ₂ CH ₃ ) ₃
The compound etc. which are represented by these are mentioned preferably.

式中、Ｒ²³は、炭素数１〜２０の直鎖、分岐又は環状のアルキル基である。Ｇは、炭素数１〜９のアルカンジイル基又はアルケンジイル基である。
Ｚ^aは、二つの珪素原子と結合することのできる基で、且つ [−０−]_0.5、[−０−Ｇ−]_0.5又は[−Ｏ−Ｇ−Ｏ−] _0.5から選ばれる基であり、複数のＺ^aは、同一でも異なっていてもよい。Ｚ^bは、二つの珪素原子と結合することのできる基で、且つ [−Ｏ−Ｇ−Ｏ−] _0.5で表される官能基であり、複数のＺ^bは、同一でも異なっていてもよい。Ｚ^cは、−Ｃｌ、−Ｂｒ、−ＯＲ^a、Ｒ^aＣ(＝Ｏ)Ｏ−、Ｒ^aＲ^bＣ＝ＮＯ−、Ｒ^aＲ^bＮ−、Ｒ^a−、ＨＯ−Ｇ−Ｏ−（Ｇは上記表記と一致する。）で表される官能基であり、複数のＺ^cは、同一でも異なっていてもよい。
また、Ｒ^aとＲ^bはそれぞれ独立して、炭素数１〜２０の直鎖、分岐又は環状のアルキル基であり、それぞれ同一でも異なっていてもよい。
ｍ、ｎ、ｕ、ｖ、ｗは、１≦ｍ≦２０、０≦ｎ≦２０、０≦ｕ≦３、０≦ｖ≦２、０≦ｗ≦１であり、且つ（ｕ／２）＋ｖ＋２ｗ＝２又は３である。ｍ、ｎ、ｕ、ｖ、ｗは、それぞれ同一でも異なっていてもよい。Ａ部が複数である場合、複数のＡ部におけるＺ^a _u、Ｚ^b _v及びＺ^c _wそれぞれは、同一でも異なっていてもよく、Ｂ部が複数である場合、複数のＢ部におけるＺ^a _u、Ｚ^b _v及びＺ^c _wそれぞれにおいは、同一でも異なってもよい。

In the formula, R ²³ is a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms. G is an alkanediyl group or alkenediyl group having 1 to 9 carbon atoms.
Z ^a is a group capable of bonding to two silicon atoms, and is a group selected from [−0−] _0.5 , [−0−G−] _0.5 or [−O—G—O—] _0.5 . , a plurality of Z ^a may be the same or different. Z ^b is a group capable of bonding to two silicon atoms and is a functional group represented by [—O—G—O—] _0.5 , and a plurality of Z ^b may be the same or different. . Z ^c is —Cl, —Br, —OR ^a , R ^a C (═O) O—, R ^a R ^b C═NO—, R ^a R ^b N—, R ^a —, HO—G—O—. (G is the same as the above notation), and the plurality of Z ^c may be the same or different.
R ^a and R ^b are each independently a linear, branched or cyclic alkyl group having 1 to 20 carbon atoms, and may be the same or different.
m, n, u, v, and w are 1 ≦ m ≦ 20, 0 ≦ n ≦ 20, 0 ≦ u ≦ 3, 0 ≦ v ≦ 2, 0 ≦ w ≦ 1, and (u / 2) + v + 2w. = 2 or 3. m, n, u, v, and w may be the same or different. When there are a plurality of A parts, Z ^a _u , Z ^b _v and Z ^c _w in the plurality of A parts may be the same or different, and when there are a plurality of B parts, Z ^a in the plurality of B parts Each of _u , Z ^b _v and Z ^c _w may be the same or different.

式中、Ｌはそれぞれ独立して炭素数１〜９のアルカンジイル基又はアルケンジイル基であり、ｘ＝ｍ、ｙ＝ｎである。 Examples of the silane coupling agent represented by the general formula (IV) include silane coupling agents represented by the formula (V), the formula (VI), and the formula (VII).

In the formula, each L is independently an alkanediyl group or alkenediyl group having 1 to 9 carbon atoms, and x = m and y = n.

As the silane coupling agent represented by the formula (V), “NXT Low-V Silane” manufactured by Momentive Performance Materials can be obtained as a commercial product.
Moreover, as a silane coupling agent represented by the formula (VI), “NXT Ultra Low-V Silane” manufactured by Momentive Performance Materials can be obtained as a commercial product.
Furthermore, as a silane coupling agent represented by the formula (VII), “NXT-Z” manufactured by Momentive Performance Materials can be obtained as a commercial product.
Since the silane coupling agent obtained by the general formula (II), formula (V) or formula (VI) has a protected mercapto group, the initial vulcanization is performed during the processing in the process before the vulcanization process. The occurrence of (scorch) can be prevented, and therefore the workability is improved.
Moreover, since the silane coupling agent obtained by Formula (V), Formula (VI), or Formula (VII) has a large number of carbon atoms in alkoxysilane, the generation of volatile organic compounds (VOC) such as alcohol is small, Environmentally preferable. Moreover, the silane coupling agent of the formula (VII) is preferable from the viewpoint of energy saving.

As the silane coupling agent, among the compounds represented by the general formulas (I) to (IV), the compound represented by the general formula (I) is preferable. This is because a polysulfide bond site that reacts with the diene polymer as the component (A) can be easily activated by a vulcanization accelerator to be added as appropriate.
In this invention, a silane coupling agent may be used individually by 1 type, and may use 2 or more types together.
When the rubber composition for conveyor belts of the present invention contains a silane coupling agent, the content is 0.1 to 1.5 parts by mass with respect to the component (A), and the value is (C) It is calculated | required from the reference | standard of 10 mass% with respect to a component. If it is this range, the energy-saving property which tends to fall with (C) component can be maintained at a high level, maintaining durability high. From this viewpoint, the amount is preferably 0.1 to 1 part by weight, more preferably 0.2 to 0.8 part by weight, and still more preferably 0.2 to 0.6 part by weight with respect to 100 parts by weight of the component (A). It is.

(Other ingredients)
To the rubber composition for conveyor belts of the present invention, other additives may be added as long as the effects of the present invention are not significantly impaired. The additive is not particularly limited as long as it is usually contained in the cover rubber of the conveyor belt. Such additives include, for example, fatty acids such as stearic acid, zinc oxide (zinc white), anti-aging agents, sulfur, vulcanization accelerators, vulcanization retarders (scorch prevention agents), oils, resins, waxes, and cracking. Agents, ozone cracking inhibitors, antioxidants, clays, calcium carbonate and the like. A commercial item can be used for these.
When using a fatty acid, the usage-amount is preferable 0.1-10 mass parts with respect to 100 mass parts of (A) component, and 1-5 mass parts is more preferable.
When using zinc oxide, the usage-amount is preferable 0.5-10 mass parts with respect to 100 mass parts of (A) component, and 1-5 mass parts is more preferable.
As the anti-aging agent, a known anti-aging agent can be selected and used. For example, N-phenyl-N ′-(1,3-dimethylbutyl) -p-phenylenediamine (6C), N-phenyl-N′-isopropyl-p-phenylenediamine (3C), 2,2,4-trimethyl -1,2-dihydroquinoline polymer (RD) and the like. When using an anti-aging agent, the amount used is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight, and 1 to 5 parts by weight with respect to 100 parts by weight of component (A). Is more preferable.

When using sulfur, the usage-amount is 0.5-10 mass parts as a sulfur content with respect to 100 mass parts of (A) component, and 0.5-4 mass parts is more preferable.
The vulcanization accelerator is not particularly limited. For example, M (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), CZ (N-cyclohexyl-2-benzothiazylsulfenamide) And guanidine vulcanization accelerators such as DPG (diphenylguanidine). When using a vulcanization accelerator, its use amount is preferably 0.1 to 5 parts by mass, more preferably 0.1 to 2 parts by mass with respect to 100 parts by mass of component (A).
The addition amount of other additives can be appropriately selected by those skilled in the art as long as the object of the present invention is not impaired.

(Method for producing rubber composition for conveyor belt)
The rubber composition for conveyor belts of the present invention is prepared by blending (A) component with (B) component, (C) component, (D) component as required, and further kneading the necessary additives as appropriate. Is obtained.
The kneading method may be in accordance with a method usually carried out by those skilled in the art. For example, using a mixer such as a Banbury mixer, Brabender, kneader, or high shear mixer, all components other than sulfur and a vulcanization accelerator are preferably 80 to 200 ° C., more preferably 100 to 180 ° C. Preferably, after kneading (A kneading) at 120 to 180 ° C., particularly preferably 130 to 170 ° C., sulfur and a vulcanization accelerator are added, and preferably 0 to 50 ° C., more preferably 0 to 0 ° C. in a kneading roll machine. A method of kneading (B kneading) at 40 ° C., more preferably 0 to 30 ° C. is preferred. If the kneading temperature during kneading A is too low, the reaction rate becomes low, while if too high, the reaction goes too far and the rubber becomes hard.
By vulcanizing the rubber composition thus obtained with a heating mold, preferably at 80 to 200 ° C., more preferably at 100 to 180 ° C., and even more preferably at 140 to 180 ° C. (both are mold temperatures), The inventive conveyor belt (outer peripheral cover rubber or inner peripheral cover rubber) can be obtained. Usually, the outer peripheral cover rubber and the inner peripheral cover rubber form a single conveyor belt with a core as a reinforcing material interposed therebetween and are attached to the belt conveyor. Since the rubber composition for conveyor belts of the present invention has both energy saving and extremely high durability, it is useful as a conveyor belt, particularly as an inner peripheral cover rubber.

EXAMPLES Next, although an Example demonstrates this invention still in detail, this invention is not limited at all by these examples.
In addition, durability and energy saving property were evaluated according to the method shown below using the rubber composition for conveyor belts obtained in each example.
(Durability-Tear resistance)
According to JIS K6252, the tearing force (N / mm) was measured using a trouser-shaped test piece, and used as an index of durability. In Table 1, it was expressed as a relative value when the tear force in Reference Example 1 was used as a reference (100). It shows that it is excellent in durability, so that a value is large.
(Energy saving-low loss)
From the rubber composition for conveyor belts obtained in each example, a sheet having a length of 40 mm, a width of 5 mm, and a thickness of 2 mm was prepared. Using such a sheet, a dynamic viscoelasticity measurement was performed with a viscoelasticity spectrometer (manufactured by Toyo Seiki Seisakusho Co., Ltd.) under the measurement conditions of a distance between chucks of 10 mm, a dynamic strain of 2%, and a frequency of 10 Hz. Tangent (tan δ) was measured. When the dynamic elastic modulus was E ′ (N / mm), tan δ / E ′ ^0.32 was obtained to obtain a low loss index. In Table 1, the values in Reference Example 1 are expressed as relative values when the reference (100) is used. It shows that it is excellent in energy saving property, so that a value is small.

Reference Example 1, Examples 1-6 and Comparative Examples 1-10
Each component excluding sulfur and vulcanization accelerator in the blending amount (unit: part by mass) shown in Table 1 is kneaded (A kneaded) at 150 ° C. with a Banbury mixer, and subsequently sulfur and vulcanization accelerator are added. A rubber composition for a conveyor belt was obtained by mixing (kneading with B), and the rubber composition was vulcanized at a mold temperature of 160 ° C. for 15 minutes to obtain a cover rubber used for the conveyor belt. The durability and energy saving property of the obtained cover rubber were evaluated. The results are shown in Table 1.

Below, each component in Table 1 is demonstrated in detail.
1) Natural rubber, grade: RSS-3 No. 2) T0700 (trade name), high cis butadiene rubber, manufactured by JSR Corporation 3) Show black N330 (HAF), nitrogen adsorption specific surface area 82 m ² / g and DBP oil absorption 102 ml / 100 g, manufactured by Cabot Japan Co., Ltd., (b-1) component 4) seast 300 (HAF-LS), nitrogen adsorption specific surface area 84 m ² / g and DBP oil absorption 72 ml / 100 g, manufactured by Tokai Carbon Co., Ltd. (b- 1) Component 5) Asahi # 65 (FEF), nitrogen adsorption specific surface area 42 m ² / g and DBP oil absorption 121 ml / 100 g, manufactured by Asahi Carbon Co., Ltd., (b-2) component 6) seast 6, nitrogen adsorption specific surface area 119 m ² / g and DBP oil absorption 114 ml / 100 g, manufactured by Tokai Carbon Co., Ltd., (b-3) component 7) Asahi # 55-HP, nitrogen adsorption ratio Surface area 30 m ² / g and DBP oil absorption 90 ml / 100 g, manufactured by Asahi Carbon Co., Ltd. (b-3) component 8) Nip seal AQ (trade name), BET surface area 220 m ² / g, manufactured by Tosoh Silica Co., Ltd. 9) Si69 ( Product name), bis (3-triethoxysilylpropyl) tetrasulfide, manufactured by Evonik Degussa Japan Co., Ltd. 10) stearic acid 300 (trade name), manufactured by Shin Nippon Rika Co., Ltd. 11) zinc white, manufactured by Toho Zinc Co., Ltd. 12) NOCRACK 6C (trade name), manufactured by Ouchi Shinsei Chemical Co., Ltd. 13) Ordinary sulfur, Sulfax Z, manufactured by Tsurumi Chemical Co., Ltd. 14) Noxeller NS-F, manufactured by Ouchi Shinsei Chemical Co., Ltd.

From Table 1, in the case of the rubber composition for belt conveyors of this invention, it turns out that energy saving property and very high durability are compatible.
On the other hand, when only the component (b-1) was contained as the component (B) and the silica of the component (C) was not contained as in the comparative example 1, the energy saving property was poor. As in Comparative Example 2, when only the component (b-2) was contained as the component (B) and the silica of the component (C) was not contained, the durability was greatly reduced.
Moreover, like Comparative Example 3, when there was too much content of silica, only durability was improved significantly and energy-saving property fell significantly.
As in Comparative Example 4, when silica was only included and the silane coupling agent (D) component was not included, the durability was high but the energy saving property was poor. It turns out that it is important to contain the silane coupling agent of (C) component with the silica of (C) component.
As in Comparative Example 5, as component (B), neither component (b-1) nor component (b-2) was used, and component (b-3), carbon black 4 and carbon black 5, were used. In this case, the durability was greatly lowered and the energy saving property was poor. When the carbon black 4 which is the component (b-3) is used instead of the component (b-2) as in the comparative example 6, the energy saving performance is greatly reduced. When carbon black 5 as the component (b-3) was used instead of the component b-2), the durability was greatly reduced. Further, as in Comparative Example 8, when the carbon black 4 as the component (b-3) was used instead of the component (b-1), the energy saving performance was greatly reduced.
As in Comparative Example 9, when the content of the component (B) was small, the durability was greatly reduced. When the total content of the component (B) was large as in Comparative Example 10, the durability was poor and the energy saving performance was reduced.

  Since the rubber composition of the present invention is excellent in energy saving and has extremely high durability, it is useful as a conveyor belt, particularly as an inner peripheral cover rubber of the conveyor belt.

Claims (6)

(A) 100 parts by mass of a diene polymer,
(B) the nitrogen adsorption specific surface area 60~100m ² / g and dibutyl phthalate oil absorption of 110 ml / 100 g than the carbon black (b-1) and a nitrogen adsorption specific than surface area 60 m ² / g and dibutyl phthalate oil absorption of 110 ml / 100 g or more Carbon black (b-2) containing 25 to 55 parts by mass of carbon black,
(C) The rubber composition for conveyor belts containing 1-15 mass parts of silicas, and (D) 0.1-1.5 mass parts of silane coupling agents.   The rubber composition for a conveyor belt according to claim 1, wherein the component (A) comprises at least one 15-65% by mass selected from natural rubber and isoprene rubber and 85-35% by mass of butadiene rubber.   The rubber composition for conveyor belts according to claim 2, wherein the cis-1,4 bond content of the butadiene rubber is 90% or more.   Furthermore, the rubber composition for conveyor belts in any one of Claims 1-3 containing 0.1-10 mass parts of anti-aging agent.   A conveyor belt obtained using the rubber composition according to claim 1.   A belt conveyor equipped with the conveyor belt according to claim 5.