JP2013122018A - Rubber composition for conveyor belt, conveyor belt, and belt conveyor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for conveyor belts which is capable of exhibiting both energy efficiency and durability, a conveyor belt in which energy efficiency and durability are both achieved, and a belt conveyer having the conveyer belt mounted thereon.SOLUTION: The rubber composition for conveyor belts includes: (A) 100 pts.mass of a diene polymer; and (B) 25-55 pts.mass of carbon black including carbon black (b-1) having a nitrogen-adsorbing specific surface area in the range of 60-100 m/g and a dibutyl phthalate oil absorption of less than 110 ml/100 g, and carbon black (b-2) having a nitrogen-adsorbing specific surface area of less than 60 m/g and a dibutyl phthalate oil absorption of at least 110 ml/100 g. Furthermore, the conveyor belt obtained using the rubber composition for conveyor belts and a belt conveyor having the conveyor belt mounted thereon are provided.

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).

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

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 is poor. .
Then, the subject of this invention is providing the rubber composition for conveyor belts which can make energy-saving property and durability compatible, and providing the conveyor belt with which energy-saving property and durability were compatible, The object is to provide a belt conveyor equipped with a 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, and (B) carbon black (b-1) having a nitrogen adsorption specific surface area of 60 to 100 m ² / g and a dibutyl phthalate oil absorption of less than 110 ml / 100 g, and a nitrogen adsorption ratio A rubber composition for conveyor belts containing 25 to 55 parts by mass of carbon black (b-2) containing a surface area of less than 60 m ² / g and a dibutyl phthalate oil absorption of 110 ml / 100 g or more.
[2] The rubber composition for a conveyor belt according to the above [1], wherein the component (A) comprises 15 to 65% by mass of natural rubber or isoprene rubber and 85 to 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].

  ADVANTAGE OF THE INVENTION According to this invention, the rubber composition for conveyor belts which can make energy-saving property and durability compatible, the conveyor belt with which energy-saving property and durability were compatible, and the belt conveyor equipped with this conveyor belt can be provided. .

[Rubber composition for conveyor belt]
The rubber composition for conveyor belts of the present invention,
(A) 100 parts by mass of a diene polymer, and (B) carbon black (b-1) having a nitrogen adsorption specific surface area of 60 to 100 m ² / g and a dibutyl phthalate oil absorption of less than 110 ml / 100 g, and a nitrogen adsorption specific surface area of 60 m ^2. / G and carbon black (b-2) having a dibutyl phthalate oil absorption of 110 ml / 100 g or more is contained, and a conveyor belt obtained by using the rubber composition contains It has both energy saving and durability.
Hereinafter, the component of the rubber composition for conveyor belts of this invention is demonstrated.

((A) Diene polymer)
Examples of the diene polymer of component (A) include natural rubber (NR), isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), ethylene-propylene rubber (EPR), ethylene- Examples include propylene-diene rubber (EPDM), butyl rubber (IIR), halogenated butyl rubber, and chloroprene rubber. 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. More preferably, rubber or isoprene rubber and butadiene rubber are used in combination.
In addition, the component (A) is preferably composed of 15 to 65% by mass of natural rubber or isoprene rubber and 85 to 35% by mass of butadiene rubber from the viewpoint of achieving both energy saving and durability, and natural rubber or isoprene rubber 20 It is more preferably composed of ˜60 mass% and butadiene rubber 80˜40 mass%, further preferably composed of natural rubber or isoprene rubber 25˜55 mass% and butadiene rubber 75˜45 mass%, natural rubber or isoprene rubber 30 It is particularly preferred that it consists of ˜45 mass% and butadiene rubber 70-55 mass%.
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 as component (B) is a carbon black (b-1) having a nitrogen adsorption specific surface area of 60 to 100 m ² / g and a dibutyl phthalate oil absorption of less than 110 ml / 100 g from the viewpoint of achieving both energy saving and durability. And carbon black (b-2) having a nitrogen adsorption specific surface area of less than 60 m ² / g and a dibutyl phthalate oil absorption of 110 ml / 100 g or more.
From the viewpoint of durability, 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 dibutyl phthalate oil absorption of 60 to 108 ml / 100 g. It is more preferable that they are 90 m < ² > / g and dibutyl phthalate oil absorption 65-108 ml / 100g.
The carbon black (b-2) is preferably a nitrogen adsorption specific surface area of 30 to 55 m ² / g and a dibutyl phthalate oil absorption of 110 to 140 ml / 100 g from the viewpoint of energy saving. It is more preferable that they are 50 m < ² > / g and dibutyl phthalate oil absorption 115-130 ml / 100g.
In the present specification, the nitrogen adsorption specific surface area and dibutyl phthalate 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 15: 85-85: 15, Most preferably, it is 20: 80-80: 20. If it is said content ratio, both durability and low-loss property 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 (above, furnace for rubber), MT carbon black (pyrolytic carbon) and the like. A rubber furnace is preferred. Among these, carbon black that meets the above-mentioned regulations may be appropriately selected and used.

In the rubber composition for a conveyor belt of the present invention, the content of the component (B) [(b-1) component + (b-2) component] is 25 to 55 parts by mass with respect to 100 parts by mass of the component (A). It is. 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.
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. It may be. When the carbon black (b-3) is contained, the content thereof is preferably 10 parts by mass or less, more preferably 5 parts by mass or less, further preferably 3 with respect to 100 parts by mass of the component (A). It is 1 part by mass or less, particularly preferably 1 part by mass or less.

(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. Examples of the additive include fatty acids such as stearic acid, zinc oxide (zinc white), anti-aging agent, sulfur, vulcanization accelerator, vulcanization retarder (scorch inhibitor), oil, resin, wax, silica, Silica coupling agents, peptizers, ozone cracking inhibitors, antioxidants, clays, calcium carbonate and the like can be mentioned. 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.

The rubber composition for conveyor belts of the present invention can be obtained by kneading the (A) component and the (B) component with appropriate additives as appropriate. The kneading method may be in accordance with a method usually carried out by those skilled in the art. For example, all components other than sulfur and a vulcanization accelerator are kneaded at 80 to 200 ° C. (preferably 10 to 180 ° C.) using a mixer such as a Banbury mixer, Brabender, kneader, or high shear mixer (A kneading). ) And then adding sulfur and a vulcanization accelerator (kneading B) and kneading at 80 to 200 ° C. (preferably 10 to 180 ° C.) with a kneading roll machine, etc. The method of kneading | mixing at 80-200 degreeC (preferably 10-180 degreeC) is mentioned.
By molding the rubber composition thus obtained with a heating mold, the conveyor belt (outer peripheral cover rubber or inner peripheral cover rubber) of the present invention 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 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 Example 1 was defined 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) under the measurement conditions of a distance between chucks of 10 mm, a dynamic strain of 2%, and a frequency of 10 Hz. 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, relative values are shown when the reciprocal of the tearing force in Example 1 is used as a reference (100). It shows that it is excellent in energy saving property, so that a value is large.

Examples 1-11 and Comparative Examples 1-5
Each component excluding sulfur and the vulcanization accelerator is kneaded (A kneading) with a Banbury mixer in the compounding amount (unit: parts by mass) shown in Table 1, and then sulfur and the vulcanization accelerator are added and mixed (B The rubber composition for conveyor belts was obtained by kneading, 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), manufactured by Cabot Japan Co., Ltd., nitrogen adsorption specific surface area of 82 m ² / g and dibutyl phthalate oil absorption 102 ml / 100 g, (b-1) component 4) Seast 300 (HAFLS), manufactured by Tokai Carbon Co., Ltd., nitrogen adsorption specific surface area 84 m ² / g and dibutyl phthalate oil absorption 72 ml / 100 g, (b -1) Component 5) Asahi # 65 (FEF), manufactured by Asahi Carbon Co., Ltd., nitrogen adsorption specific surface area 42 m ² / g and dibutyl phthalate oil absorption 121 ml / 100 g, (b-2) component 6) seast 6, nitrogen adsorption Specific surface area of 119m ² / g and dibutyl phthalate oil absorption of 114ml / 100g, Tokai Carbon Co., Ltd. 7) Asahi # 55-HP, Nitrogen adsorption specific surface area 30 m ² / g and dibutyl phthalate oil absorption 90 ml / 100 g, Asahi Carbon Co., Ltd. 8) Stearic acid 300 (trade name), Shin Nippon Rika Co., Ltd. 9 ) Zinc Hana, Toho Zinc Co., Ltd. 10) Nocrack 6C (trade name), Ouchi Shinsei Chemical Co., Ltd. 11) Ordinary sulfur, Sulfax Z, Tsurumi Chemical Co., Ltd. 12) Noxeller NS-F, Ouchi Eshin Made by Chemical Industry 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 durability are compatible.
On the other hand, only the component (b-1) is contained as the component (B) as in Comparative Examples 1 and 2, and only the component (b-2) is used as the component (B) as in Comparative Example 3. When it contained only, durability fell significantly. In addition, as in Comparative Example 4, when the total content of the component (B) with respect to 100 parts by mass of the component (A) was less than 25 parts by mass, the durability was remarkably reduced. As in Comparative Example 5, when a combination of carbon blacks not corresponding to any of the components (b-1) and (b-2) defined in the present invention was used, the durability was remarkably reduced. Further, as in Comparative Examples 6 to 8, although either one of the component (b-1) and the component (b-2) is used, the carbon black to be combined is the component (b-1) defined in the present invention and When the component does not correspond to any of the components (b-2), it was impossible to achieve both durability and energy saving. And like Comparative Example 9, when content of (B) component exceeded 55 mass parts with respect to 100 mass parts of (A) component, durability fell remarkably.

  Since the rubber composition of the present invention is excellent in both energy saving and durability, it can be used for a conveyor belt, particularly an inner cover belt of the conveyor belt.

Claims (6)

(A) 100 parts by mass of a diene polymer, and (B) carbon black (b-1) having a nitrogen adsorption specific surface area of 60 to 100 m ² / g and a dibutyl phthalate oil absorption of less than 110 ml / 100 g, and a nitrogen adsorption specific surface area of 60 m ^2. / G and a rubber composition for conveyor belts containing 25 to 55 parts by mass of carbon black (b-2) containing dibutyl phthalate oil absorption of 110 ml / 100 g or more.   The rubber composition for conveyor belts according to claim 1, wherein the component (A) comprises 15 to 65 mass% of natural rubber or isoprene rubber and 85 to 35 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.