JP2003221470A - Rubber composition for power transmission belt and power transmission belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rubber composition which is easily processed in the uncrosslinked state such as rolling and molding, without the viscosity rising, and a belt which has a very high hardness and high strengths after crosslinking. <P>SOLUTION: In the belt comprising as a major component a hydrogenated nitrile rubber containing a metal salt of an unsaturated carboxylic acid, the hydrogenated nitrile rubber comprises the metal salt of the unsaturated carboxylic acid as a matrix rubber, 10-60 parts by mass of silica added to 100 parts by mass of the matrix rubber, and 5-20 parts by mass of triallylisocyanurate or triallycyanurate formulated as the co-crosslinker, and is crosslinked with an organic peroxide. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition for a power transmission belt and a belt, and more particularly to a belt using hydrogenated nitrile rubber containing an unsaturated metal salt of a carboxylic acid, which is used for increasing hardness and processing such as rolling. TECHNICAL FIELD The present invention relates to a rubber composition for a transmission belt having excellent properties and a transmission belt.

[0002]

2. Description of the Related Art In recent years, the operating environment temperature of a belt for transmitting power has risen with the increase in output and rotation of an engine, and the load required on the belt has also increased. Conventionally, chloroprene rubber was mainly used as a material for conventional belts, but chloroprene rubber easily cures in a high temperature atmosphere, causing early cracking due to curing, and the belt falls into the pulley due to insufficient lateral pressure rigidity in a high temperature atmosphere. It deforms like this and causes buckling deformation called dishing, which makes it impossible to transmit power, or peeling between the core wire and the adhesive rubber causes pop-outs such as pop-out of the core wire, leading to belt life. There was an occasion.

Therefore, as disclosed in Patent Document 1, a belt having excellent wear resistance and heat resistance is prepared by dispersing an unsaturated carboxylic acid metal salt such as zinc methacrylate in hydrogenated nitrile rubber (H-NBR). Belts using rubber have been proposed.

Further, in Patent Document 2, silica and triallyl isocyanurate may be blended with a rubber in which an unsaturated carboxylic acid metal salt such as zinc methacrylate is dispersed in hydrogenated nitrile rubber to improve strength. That is disclosed.

[0005]

[Patent Document 1] Japanese Unexamined Patent Publication No. 5-271472

[Patent Document 2] Japanese Unexamined Patent Publication No. 5-39364

[0006]

However, the demand for high load transmission is further increasing. In addition, simply using a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt,
Since the unvulcanized rubber has a high viscosity and is inferior in workability, it is possible to provide a rubber that has a higher hardness than before and has excellent workability such as rollability. It was wanted.

Therefore, in the present invention, a belt made of a rubber containing a hydrogenated nitrile rubber containing an unsaturated metal salt of a carboxylic acid as a main component is required to have an extremely high hardness without deteriorating workability such as rolling property. An object of the present invention is to provide a rubber composition for a transmission belt and a transmission belt that can be manufactured.

[0008]

In order to achieve the above-mentioned object, in claim 1 of the present invention, a rubber composition for a power transmission belt containing a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt as a main component. In the above, a hydrogenated nitrile rubber (H-NBR) containing an unsaturated carboxylic acid metal salt is used as a matrix rubber, 10 to 60 parts by mass of silica is added to 100 parts by mass of the matrix rubber, and triallyl is used as a co-crosslinking agent. It is characterized by comprising 5 to 20 parts by mass of isocyanurate (TAIC) or triallyl cyanurate (TAC) and comprising a rubber crosslinked with an organic peroxide.

As described above, by adding a large amount of silica and a specific co-crosslinking agent to H-NBR containing an unsaturated carboxylic acid metal salt, the viscosity does not increase during non-crosslinking, and processing such as rolling or molding is possible. It is easy, and after crosslinking, a belt having very high hardness and high strength can be obtained.

In the second aspect, the matrix rubber is a rubber composition for a power transmission belt, which is a blend of hydrogenated nitrile rubber containing unsaturated carboxylic acid metal salt and hydrogenated nitrile rubber in a ratio of 1: 1 to 1: 9. It is supposed to be a thing.

It is possible to blend H-NBR containing an unsaturated carboxylic acid metal salt and H-NBR containing no unsaturated carboxylic acid metal salt, if necessary.

In the third aspect, the amount of silica is 30 to 60.
This is a rubber composition for a power transmission belt, which is part by mass, and a belt with higher hardness can be obtained by limiting the compounding amount of silica to a larger range.

According to a fourth aspect of the present invention, in a transmission belt having a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt as a main component and used for transmission or conveyance, the hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt is used. As a matrix rubber, 10 to 60 parts by mass of silica is added to 100 parts by mass of the matrix rubber, 5 to 20 parts by mass of triallyl isocyanurate or triallyl cyanurate and 0. 2-10
It is characterized in that a mass part is added.

As described above, by adding a large amount of silica and a specific co-crosslinking agent to H-NBR containing an unsaturated carboxylic acid metal salt, the viscosity does not increase during non-crosslinking and processing such as rolling or molding is possible. It is easy, and after crosslinking, a belt having very high hardness and high strength can be obtained.

In the fifth aspect, the matrix rubber is a transmission belt which is a blend of hydrogenated nitrile rubber containing unsaturated carboxylic acid metal salt and hydrogenated nitrile rubber in a ratio of 1: 1 to 1: 9.

If desired, it is possible to blend and use H-NBR containing an unsaturated carboxylic acid metal salt and H-NBR containing no unsaturated carboxylic acid metal salt.

In the sixth aspect, the silica content is 30 to 60.
The transmission belt, which is a mass part, is used, and a belt having higher hardness can be obtained by limiting the compounding amount of silica to a larger range.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a cross-sectional perspective view of a main part of a toothed belt showing an example of the belt of the present invention.

FIG. 1 is an example of a toothed belt according to the present invention. The toothed belt 1 of the present invention is made of a rope having a low elongation and a high strength such as a glass fiber cord or an aramid cord along the longitudinal direction of the belt. A tooth rubber 6 having a tooth cloth 5 laminated on the outer surface is arranged below the adhesive rubber 3 in which the core wire 4 is embedded,
It is configured by layering the back rubber 2 on top of the adhesive rubber 3.

Here, the above toothed belt 1 uses, as a raw material rubber for the adhesive rubber layer 3, the tooth rubber layer 6 and the back rubber layer 2, hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt as a matrix rubber, Silica is contained in an amount of 10 to 60 parts by mass, preferably 30 to 100 parts by mass of the matrix rubber.
To 60 parts by mass, and 5 to 20 parts by mass of triallyl isocyanurate (TAIC) or triallyl cyanurate (TAC) as a co-crosslinking agent and 0.2 to 10 parts by mass of organic peroxide are crosslinked. It consists of things.

The hydrogenated nitrile rubber used as the raw rubber is not particularly limited, but the hydrogenation rate is 80%.
It is above, and 90% or more is particularly preferable in order to exhibit the characteristics of heat resistance and ozone resistance. Hydrogenated nitrile rubbers with a hydrogenation rate of less than 80% are not preferable because they have extremely low heat resistance and ozone resistance. Considering the heat resistance, the iodine value is preferably 5 to 35, and the oil resistance and cold resistance are further improved. From the viewpoint of sex, the amount of bound acrylonitrile is 20-40%
Is preferred. In addition, Mooney viscosity (ML1 + 4
It is preferable that (100 ° C.)) is 70 to 85 in order to improve the mechanical strength and lateral pressure rigidity and to improve the flexibility and workability.

The unsaturated carboxylic acid metal salt is an ionic bond between an unsaturated carboxylic acid having a carboxyl group and a metal, and examples of the unsaturated carboxylic acid include monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid and fumaric acid. acid,
Dicarboxylic acids such as itaconic acid are preferable, and as the metal, beryllium, magnesium, calcium, strontium, barium, titanium, chromium, molybdenum, manganese, iron, cobalt, nickel, copper, silver, zinc, cadmium, aluminum, tin, lead. , Antimony, etc. can be used.

The composition ratio of the hydrogenated nitrile rubber to the unsaturated carboxylic acid metal salt is 98: 2 to 55:45.
If the proportion of hydrogenated nitrile rubber is more than 98, the abrasion resistance becomes insufficient, and if it is less than 55, the abrasion resistance is good, but the flexibility of the belt is deteriorated, which is not preferable. Further, in order to adjust this composition ratio, it is also possible to blend a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt with a usual hydrogenated nitrile rubber to obtain a matrix rubber.

The organic peroxide is used as a cross-linking agent, and includes di-t-butyl peroxide, dicumyl peroxide, t-butyl cumyl peroxide,
1,1-t-butylperoxy-3,3,5-trimethylcyclohexane, 2,5-di-methyl-2,5-di (t
-Butylperoxy) hexane-3, bis (t-butylpoeroxy-di-isopropyl) benzene, 2,5-di-
Methyl-2,5-di (benzoylperoxy) hexane,
Examples thereof include t-butylperoxybenzoate and t-butylperoxy-2-ethyl-hexyl carbonate. Matrix rubber 100
0.2 to 10 parts by mass with respect to parts by mass. If it is less than 0.2 parts by mass, crosslinking will not be sufficiently carried out, and if it exceeds 10 parts by mass, sufficient elasticity will not be obtained.

Silica is added in an amount of 10 to 60 parts by mass, more preferably 30 to 60 parts by mass, based on 100 parts by mass of the matrix rubber. If it is less than 10 parts by mass, the adhesive force between the rubber and the core wire will be poor, leading to a failure such as popping out due to the separation of the core wire, and if it exceeds 60 parts by mass, the viscosity in the unvulcanized state will increase and the belt will It is not preferable because it cannot be molded. Further, it is preferable that the amount is 30 parts by mass or more because a belt having higher hardness can be obtained.

Generally, as the co-crosslinking agent, TAIC, T
AC, 1,2 polybutadiene, a metal salt of an unsaturated carboxylic acid, oximes, guanidine, trimethylolpropane trimethacrylate, ethylene glycol dimethacrylate, N-N'-m-phenylene bismaleimide, and TAIC are used in the present invention. At least one of TAC and TAC is used. By using TAIC or TAC, the hardness of the rubber after crosslinking can be made higher than when other co-crosslinking agents are used, and since the viscosity of the uncrosslinked rubber is not raised too much, processing and moldability are deteriorated. Never. Moreover, the compounding quantity of these co-crosslinking agents shall be 5-20 mass parts. If the amount is less than 5 parts by mass, the hardness of the belt cannot be sufficiently cited, and if the amount is more than 20 parts by mass, the degree of crosslinking becomes too large and the tear resistance becomes small, which is not preferable.

In addition to the above, fillers such as carbon black, calcium carbonate, and talc, which are usually compounded in rubber, for improving abrasion resistance, crosslinking aids, crosslinking accelerators, plasticizers, stabilizers, processing aids. It is possible to add additives such as anti-aging agent and colorant according to the purpose of use.
Means commonly used for mixing these compounding agents,
For example, a method of kneading using a Banbury mixer or a kneader can be mentioned.

As the core wire 4, a rope having a low elongation and a high strength is used, and an organic material such as aramid fiber, polyamide fiber, polyethylene terephthalate fiber, polyester fiber having ethylene-2,6-naphthalate as a main constituent unit is used. Examples include a twisted rope made of fibers, inorganic fibers such as glass fibers, and metal fibers. The core wire 4 is generally bonded to the adhesive rubber 3 by a resorcin-formalin-latex treatment. Further, a surface treated with resorcin-formalin-latex and further coated with rubber paste may be used.

As such an adhesion treatment, the fiber is immersed in resorcin-formalin-latex (RFL solution),
Generally, it is dried by heating to uniformly form an adhesive layer on the surface. However, the method is not limited to this, and there is also a method of performing pretreatment with an epoxy or isocyanate compound and then treating with an RFL solution.

The RFL solution is a mixture of latex with an initial condensate of resorcin and formalin. As the latex used here, chloroprene, styrene / butadiene / vinyl pyridine ternary polymer, hydrogenated nitrile, NBR, etc. are used. However, hydrogenated nitrile rubber is preferable as a constituent raw material for the adhesive rubber layer and the back rubber layer.

As the tooth cloth 5, a cloth woven or knitted into a plain weave, a twill weave, a satin weave, or the like is used by using a filamentous or spun yarn made of cotton, polyamide, polyethylene terephthalate, or aramid fiber. These are then subjected to an RFL treatment for adhesion treatment to make the thickness harder, and to prevent wrinkles from being formed on the tubular belt canvas during the spinning process. RFL processing is RF
After immersing in L liquid for 0.1 to 20 seconds, 100 to 200 ° C
And dry for 30 to 600 seconds.

The RFL solution used in this RFL treatment is a mixture of an initial condensate of resorcin and formalin and rubber latex as in the case of the above-mentioned core wire. In this case, the molar ratio of resorcin and formalin is 1: 0. .5-3
It is suitable to increase the adhesive strength. The initial condensate of resorcin and formalin has a resin content of 10 to 1 with respect to 100 parts by weight of rubber content of latex.
It is mixed with latex so that the amount thereof is 00 parts by weight, and the total solid content is adjusted to be 5 to 40%.

In some cases, the RFL solution may be mixed with a carbon black solution to blacken the treated product. In the case of cotton fabric, a known surfactant is added to the RFL solution in an amount of 0.1 to 1
It is advisable to add 3.0% by weight.

The above latex is styrene-butadiene-
Hynyl pyridine is also a latex of a polymer, chlorosulphonated polyethylene, hydrogenated nitrile rubber, shrimp chlorohydrin, natural rubber, SBR, chloroprene rubber, olefin-vinyl ester copolymer, etc., and an adhesive rubber layer as before, Hydrogenated nitrile rubber is preferable in relation to the constituent raw material of the back rubber layer.

In the above description, the example in which the present invention is applied to the toothed belt has been described, but the kind of the belt is not limited to the toothed belt, and the adhesive rubber layer in which the core wire 23 is embedded as shown in FIG. 24 and a compressed rubber 26, and a cut edge type V belt 2 in which a canvas 22 with rubber is laminated on each surface layer of the adhesive rubber layer 24 and the compressed rubber layer 26.
No. 1 or a belt such as a V-ribbed belt (not shown), and various belts for power transmission and transportation can be applied.

[0036]

EXAMPLES Next, rubber was kneaded in the composition shown in Table 1 to prepare each rubber sheet, and its physical properties were measured. The results are shown in Table 2.
Shown in.

[0037]

[Table 1]

[0038]

[Table 2]

The number of teeth: 120, tooth pitch: 9.5
A toothed belt having a width of 25 mm and a belt width of 30 mm was prepared, and a running test was conducted with the layout shown in FIG. In the running test, the thrust force and the degree of end face damage were evaluated. The degree of end face damage was evaluated as follows. Marks were placed on the entire tooth portions with white ink on both tooth portions of the running test belt, and the running belt was run at 4000 rpm for 200 hours, and damage to the end surface was evaluated according to the disappearance of the marks after running as shown in Table 3 below. The results of the running test are shown in Table 4.

[0040]

[Table 3]

[0041]

[Table 4]

As can be seen from the results of Tables 2 and 4,
In Comparative Example 1, since the amount of TAIC is as small as 2 parts by mass, sufficient hardness cannot be obtained, slippage on the back surface is reduced, and thrust force is also increased. In Comparative Examples 2 to 3, since silica was not added, the adhesive force to the core wire was not obtained and interfacial peeling occurred. In Comparative Example 4, since H-NBR alone containing no unsaturated carboxylic acid was used, the degree of end face damage was large because the hardness was not so high and slippage was small. Comparative Example 5 is N-N'-m as a co-crosslinking agent.
-Example of using phenylene bismaleimide,
In the uncrosslinked state, the viscosity of the rubber was too high, and the tooth mold could not be molded.

On the other hand, in Examples 1 to 5, due to the interaction between TAIC or TAC and the increase in the amount of silica, the hardness was greatly increased and the adhesion state with the core wire was also good, and a failure phenomenon such as peeling occurred. There wasn't. Example 6
As for the above, it is understood that when the amount of H-NBR containing the unsaturated metal carboxylic acid salt is too large, although it is within the range of Examples, the adhesive strength is reduced although the rubber has high hardness.

In Comparative Examples 7 and 8, the amount of silica is 40 to 60 parts by mass, which is particularly large, and the shape of the stress-strain curve is different from that in the case of adding carbon. The value of is low and the value of EB is high. However, the adhesive strength and the physical properties of the belt were good.

[0045]

As described above, according to claim 1 of the present invention, in the rubber composition for a power transmission belt which is mainly composed of a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt and is used for power transmission or transportation, the unsaturated Hydrogenated nitrile rubber (H-NBR) containing a carboxylic acid metal salt was used as a matrix rubber, and 10 to 60 parts by mass of silica was added to 100 parts by mass of the matrix rubber, and triallyl isocyanurate (TAIC) as a co-crosslinking agent. ) Or triallyl cyanurate (TAC) in an amount of 5 to 20 parts by mass and crosslinked with an organic peroxide.

As described above, by adding a large amount of silica and a specific co-crosslinking agent to H-NBR containing an unsaturated carboxylic acid metal salt, the viscosity does not increase during non-crosslinking and processing such as rolling or molding is possible. It is easy, and after crosslinking, a belt having very high hardness and high strength can be obtained.

In the second aspect, the matrix rubber is a rubber composition for a power transmission belt, which is a blend of hydrogenated nitrile rubber containing unsaturated carboxylic acid metal salt and hydrogenated nitrile rubber in a ratio of 1: 1 to 1: 9. It is supposed to be a thing.

If necessary, it is possible to blend and use H-NBR containing an unsaturated carboxylic acid metal salt and H-NBR containing no unsaturated carboxylic acid metal salt.

In the third aspect, the amount of silica is 30 to 60.
This is a rubber composition for a power transmission belt, which is part by mass, and a belt with higher hardness can be obtained by limiting the compounding amount of silica to a larger range.

In a fourth aspect of the present invention, in a transmission belt mainly composed of hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt and used for transmission or conveyance, the hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt is used. As a matrix rubber, 10 to 60 parts by mass of silica is added to 100 parts by mass of the matrix rubber, 5 to 20 parts by mass of triallyl isocyanurate or triallyl cyanurate and 0. 2-10
It is characterized in that a mass part is added.

As described above, by adding a large amount of silica and a specific co-crosslinking agent to H-NBR containing an unsaturated carboxylic acid metal salt, the viscosity does not increase during non-crosslinking and processing such as rolling or molding is possible. It is easy, and after crosslinking, a belt having very high hardness and high strength can be obtained.

According to a fifth aspect of the present invention, the matrix rubber is a transmission belt which is a blend of a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt and a hydrogenated nitrile rubber in a ratio of 1: 1 to 1: 9.

If necessary, it is possible to blend and use H-NBR containing an unsaturated carboxylic acid metal salt and H-NBR containing no unsaturated carboxylic acid metal salt.

In the sixth aspect, the amount of silica blended is 30 to 60.
The belt is a mass part, and a belt having higher hardness can be obtained by limiting the blending amount of silica to a larger range.

[Brief description of drawings]

FIG. 1 is a cross-sectional perspective view of essential parts of a toothed belt that is an example of the present invention.

FIG. 2 is a cross-sectional view of a cut edge type belt that is another example of the present invention.

FIG. 3 is a schematic diagram showing a layout of a running test.

[Explanation of symbols]

1 toothed belt 2 back rubber 3 adhesive rubber 4 cores 5 tooth cloth 6 tooth rubber 21 V belt 31 belt 32 cam pulley 33 Water pump drive pulley 34 crank pulley 35 Tensioner pulley 36 idler

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F16G 1/06 F16G 1/06

Claims (6)

[Claims] 1. A rubber composition for a belt, comprising a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt as a main component, which is used for transmission or conveyance, and which comprises a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt. As a matrix rubber, 10 to 60 parts by mass of silica is added to 100 parts by mass of the matrix rubber, 5 to 20 parts by mass of triallyl isocyanurate or triallyl cyanurate and 0. A rubber composition for a power transmission belt, which is added in an amount of 2 to 10 parts by mass. 2. The power transmission belt according to claim 1, wherein the matrix rubber is a blend of hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt and hydrogenated nitrile rubber in a ratio of 1: 1 to 1: 9. Rubber composition. 3. The rubber composition for a power transmission belt according to claim 1, wherein the compounding amount of silica is 30 to 60 parts by mass. 4. A belt, which is mainly composed of a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt and is used for transmission or conveyance, uses the hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt as a matrix rubber, Silica is added in an amount of 10 to 6 with respect to 100 parts by mass of the matrix rubber.
A transmission belt comprising 0 part by mass of rubber, and 5 to 20 parts by mass of triallyl isocyanurate or triallyl cyanurate as a co-crosslinking agent, and a rubber crosslinked with an organic peroxide. 5. The transmission belt according to claim 4, wherein the matrix rubber is a blend of a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt and a hydrogenated nitrile rubber in a ratio of 1: 1 to 1: 9. 6. The power transmission belt according to claim 4, wherein the compounding amount of silica is 30 to 60 parts by mass.