JP4633366B2 - Rubber composition for belt and rubber belt - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a rubber composition for a belt and a rubber belt, and more particularly to a belt rubber composition using a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt and having high workability such as rolling and the like. Articles and rubber belts.

  In recent years, with the increase in engine output and rotation, the operating environment temperature of the belt for transmitting power has increased, and the load required for the belt has increased. Conventional belts are mainly made of chloroprene rubber. However, chloroprene rubber is easy to cure under high atmosphere, and cracks due to curing occur early, or the belt falls into the pulley due to insufficient side pressure rigidity under high temperature atmosphere. This causes a buckling deformation called dishing, which makes it impossible to transmit power, or causes a failure such as pop-out where the core wire pops out due to the separation of the core wire and adhesive rubber, leading to the belt life There was a thing.

  Therefore, as disclosed in Patent Document 1, a rubber in which an unsaturated carboxylic acid metal salt such as zinc methacrylate is dispersed in hydrogenated nitrile rubber (H-NBR) as a belt excellent in wear resistance and heat resistance. Used belts have been proposed.

  Patent Document 2 also states that silica and triallyl isocyanurate may be blended with rubber obtained by dispersing unsaturated carboxylic acid metal salt such as zinc methacrylate in hydrogenated nitrile rubber to improve strength. It is disclosed.

JP-A-5-271472 JP-A-5-39364

  However, the demand for high load transmission is further increased. Also, simply using a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt has the disadvantage that the viscosity of the unvulcanized rubber becomes high and the processability is inferior. The present invention provides a rubber composition for a belt and a rubber belt that are higher than those described above, and that can increase the hardness without degrading workability such as rollability.

The present invention relates to a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt in a rubber composition for belts used for transmission or conveyance comprising a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt and a hydrogenated nitrile rubber. And hydrogenated nitrile rubber as a matrix rubber, 10 to 60 parts by mass of silica are added to 100 parts by mass of the matrix rubber, 1 to 10 parts by mass of trimethylolpropane methacrylate and 0% of an organic peroxide as a co-crosslinking agent. The rubber composition for a belt is characterized by adding 0.2 to 10 parts by mass.

  According to a second aspect of the present invention, the matrix rubber is a mixture 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. The rubber composition for a belt described.

Invention of Claim 3 exists in the rubber composition for belts of Claim 1 or 2 whose compounding quantity of a silica is 30-60 mass parts with respect to 100 mass parts of this matrix rubber .

The invention according to claim 4 is a hydrogenation nitrile rubber containing an unsaturated carboxylic acid metal salt and a hydrogenation containing an unsaturated carboxylic acid metal salt in a belt used for power transmission or transportation comprising the hydrogenated nitrile rubber . Nitrile rubber and hydrogenated nitrile rubber are used as matrix rubber, 10 to 60 parts by mass of silica are added to 100 parts by mass of the matrix rubber, 1 to 10 parts by mass of trimethylolpropane methacrylate as a co-crosslinking agent, and organic peroxidation It is in a rubber belt made of rubber crosslinked with a product.

According to a fifth aspect of the present invention, the matrix rubber is a mixture 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. It is in the rubber belt of description.

The invention according to claim 6 is the rubber belt according to claim 4 or 5, wherein the addition amount of silica is 30 to 60 parts by mass with respect to 100 parts by mass of the matrix rubber .

According to the present invention, a hydrogenated nitrile containing an unsaturated carboxylic acid metal salt is used in a rubber composition for belts used for transmission or transportation comprising a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt and a hydrogenated nitrile rubber. A rubber and a hydrogenated nitrile rubber are used as a matrix rubber, 10 to 60 parts by mass of silica is added to 100 parts by mass of the matrix rubber, 1 to 10 parts by mass of trimethylolpropane methacrylate and an organic peroxide are added as a co-crosslinking agent. Since it is a rubber composition for belts characterized by adding 0.2 to 10 parts by mass, hydrogenated nitrile rubber (H-NBR) containing an unsaturated carboxylic acid metal salt and silica and a specific co-crosslinking agent When blended in large quantities, the viscosity does not increase when uncrosslinked, and processing such as rolling and molding is easy. A belt with very high hardness and high strength can be obtained. In addition, trimethylolpropane trimethacrylate has higher elongation after crosslinking than other co-crosslinking agents, and is excellent in tear resistance.

  According to the invention described in claim 2, the matrix rubber is a mixture 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. Therefore, it is necessary to blend H-NBR containing an unsaturated carboxylic acid metal salt and H-NBR not containing an unsaturated carboxylic acid metal salt, if necessary. It becomes possible.

According to the invention described in claim 3, the amount of silica is 30 to 60 parts by mass with respect to 100 parts by mass of the matrix rubber. By limiting the blending amount to a larger range, a belt with higher hardness can be obtained.

According to the invention described in claim 4, hydrogenated nitrile rubber and hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt are used as a matrix rubber, and 10 to 60 parts by mass of silica is added to 100 parts by mass of the matrix rubber. And 1 to 10 parts by mass of trimethylolpropane methacrylate as a co-crosslinking agent, and since it is in a rubber belt made of rubber crosslinked with an organic peroxide, hydrogenated nitrile rubber containing unsaturated carboxylic acid metal salt and silica By blending a large amount of a specific co-crosslinking agent, it is easy to process such as rolling and molding without increasing the viscosity when not cross-linked. In addition, there is an effect that a belt having high hardness, strength and tear resistance can be obtained.

  According to the invention described in claim 5, the matrix rubber is a mixture 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. Therefore, it is possible to blend a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt and a hydrogenated nitrile rubber not containing an unsaturated carboxylic acid metal salt as necessary. There is an effect.

According to the invention described in claim 6, since the amount of silica added is 30 to 60 parts by mass with respect to 100 parts by mass of the matrix rubber, since the rubber belt according to claim 4 or 5 is present, the amount of silica added is By limiting to a larger range, a belt with higher hardness can be obtained.

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

  Here, in the toothed belt 1, a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt is used as a matrix rubber as a raw material rubber for the adhesive rubber layer 3, the tooth rubber layer 6, and the back rubber layer 2. Silica is added in an amount of 10 to 60 parts by mass, more preferably 30 to 60 parts by mass, and 1 to 10 parts by mass of trimethylolpropane trimethacrylate and 0.2 to 10 parts of organic peroxide as a co-crosslinking agent. It consists of a rubber cross-linked product with parts by mass.

  The hydrogenated nitrile rubber used for the raw rubber is not particularly limited, but the hydrogenation rate is 80% or more, and particularly 90% or more is preferable in order to exhibit heat resistance and ozone resistance characteristics. Hydrogenated nitrile rubber having a hydrogenation rate of less than 80% is not preferable because the heat resistance and ozone resistance are extremely lowered. In consideration of heat resistance, the iodine value is preferably 5 to 35, and further oil resistance and cold resistance. From the viewpoint of properties, the amount of bound acrylonitrile is preferably in the range of 20 to 40%. Further, it is preferable that the Mooney viscosity (ML1 + 4 (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 of an unsaturated carboxylic acid having a carboxyl group and a metal. Examples of the unsaturated carboxylic acid include monocarboxylic acids such as acrylic acid and methacrylic acid, maleic acid, fumaric acid, and itacone. Dicarboxylic acids such as acids are preferred, and the metals include beryllium, magnesium, calcium, strontium, barium, titanium, chromium, molybdenum, manganese, iron, cobalt, nickel, copper, silver, zinc, cadmium, aluminum, tin, lead, Antimony or the like can be used.

  And the composition ratio of hydrogenated nitrile rubber and unsaturated carboxylic acid metal salt shall be 98: 2-55: 45. If the proportion of hydrogenated nitrile rubber is greater than 98, the wear resistance will be insufficient, and if it is less than 55, the wear resistance will be good, but the flexibility of the belt will be poor, which is not preferable. In order to adjust the composition ratio, a hydrogenated nitrile rubber containing an unsaturated carboxylic acid metal salt and a normal hydrogenated nitrile rubber can be blended to form a matrix rubber.

  The organic oxide is used as a crosslinking agent and is 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 (benzoylperoxy) hexane, t-butylperoxybenzoate, t-butylperoxy-2-ethyl-hexyl carbonate, etc. it can. The blending amount is 0.2 to 10 parts by mass with respect to 100 parts by mass of the matrix rubber. If the amount is less than 0.2 parts by mass, crosslinking is not sufficiently performed, and if it exceeds 10 parts by mass, sufficient elasticity cannot be obtained.

  Silica is blended in an amount of 10 to 60 parts by mass, more preferably 30 to 60 parts by mass with respect to 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 failure such as popping out of the core wire, and if it exceeds 60 parts by mass, the unvulcanized viscosity will increase. Is not preferable because it cannot be molded. Moreover, it is preferable that it is 30 mass parts or more from the viewpoint that a belt with higher hardness can be obtained.

  Generally, co-crosslinking agents include sulfur compounds, oxime nitroso compounds, monomers, polymers, and other NN'-m-phenylene bismaleimides. In the present invention, monomers trimethylolpropane trimethacrylate are used. Use. By using trimethylolpropane trimethacrylate, the viscosity of the uncrosslinked rubber is not increased too much, so that processing and moldability are not deteriorated. Moreover, compared with other co-crosslinking agents, the elongation of the vulcanizate is increased and the tear resistance is excellent. The amount of the co-crosslinking agent is in the range of 1 to 10 parts by mass. If it is less than 1 part by mass, the hardness of the belt cannot be sufficiently increased, and if it exceeds 10 parts by mass, the degree of crosslinking becomes too large and the tear resistance is reduced, which is not preferable.

  Besides the above, fillers such as carbon black, calcium carbonate, talc, etc., which are usually blended in rubber, improve wear resistance, crosslinking aids, plasticizers, stabilizers, processing aids, anti-aging agents, coloring agents. It is possible to add additives such as according to the purpose of use. The method of mixing these compounding agents also includes a method of kneading using a commonly used means such as a Banbury mixer or a kneader.

  As the core wire 4, a low-stretch high-strength rope is used, and organic fibers such as aramid fibers, polyamide fibers, polyethylene terephthalate fibers, polyester fibers mainly composed of ethylene-2,6-naphthalate, and glass fibers. And twisted ropes made of inorganic fibers and metal fibers. As the core 4, a surface treated with resorcin-formalin-latex and further coated with rubber paste or the like is generally used.

  As such an adhesion treatment, it is common to immerse the fiber in resorcin-formalin-latex (RFL solution) and then heat-dry to form a uniform adhesion layer on the surface. However, the present invention is not limited to this, and there is a method of performing a pretreatment with an epoxy or isocyanate compound and then treating with an RFL solution.

  The RFL liquid is obtained by mixing an initial condensate of resorcin and formalin into a latex. Examples of the latex used here include chloroprene, styrene / butadiene / vinylpyridine ternary polymers, hydrogenated nitriles, NBR, and the like. However, hydrogenated nitrile rubber is preferred from the constituent raw materials of the adhesive rubber layer and the back rubber layer.

  As the tooth cloth 5, a cloth woven or knitted into plain weave, twill weave, satin weave, or the like using a filament or spun yarn made of cotton, polyamide, polyethylene terephthalate, or aramid fiber is used. These are then bonded by RFL to harden the thickness and prevent wrinkling of the cylindrical belt canvas in the spinning process. The RFL treatment is immersed in the RFL solution for 0.1 to 20 seconds and then dried at 100 to 200 ° C. for 30 to 600 seconds.

  The RFL solution used in this RFL treatment is a mixture of resorcin and formalin initial condensate and rubber latex, similar to that of the core wire. In this case, the molar ratio of resorcin to formalin is 1: 0.5. It is suitable to increase the adhesive strength to 3. The initial condensate of resorcin and formalin is mixed with latex so that the resin content is 10 to 100 parts by mass with respect to 100 parts by mass of latex rubber, and the total solid concentration is 5 to 40. % Adjusted.

  In some cases, the RFL solution is mixed with a carbon black solution as appropriate to black the process. In the case of cotton fabric, 0.1 to 13.0% by mass of a known surfactant may be added to the RFL solution.

  The latex is a latex of styrene-butadiene-vinylpyridine terpolymer, chlorosulfonated polyethylene, hydrogenated nitrile rubber, shrimp chlorohydrin, natural rubber, SBR, chloroprene rubber, olefin-vinyl ester copolymer, etc. Like the above, hydrogenated nitrile rubber is preferable in relation to the constituent raw materials of the adhesive rubber layer and the back rubber layer.

  In the above description, an example in which the present invention is applied to a toothed belt has been described. However, the type of belt is not limited to a toothed belt, and an adhesive rubber layer 24 in which a core wire 23 is embedded as shown in FIG. Further, a cut edge type V-belt 21 having a rubber canvas 22 laminated on each surface layer of the adhesive rubber layer 24 and the compressed rubber layer 26, a belt such as a V-ribbed belt (not shown), or a belt. The application can be applied to various belts for power transmission and conveyance.

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

  Further, a toothed belt having 132 teeth, a tooth pitch of 13 mm, and a belt width of 20 mm was prepared, and a running test was performed with a layout as shown in FIG. Table 3 shows the results of the running test.

As can be seen from the results in Table 2, since Comparative Example 1 was a carbon black reinforcement, the adhesive strength was low, and peeling occurred from the root portion of the tooth, resulting in a lifetime. In Comparative Example 3, the hardness was low and the tooth strength was insufficient, and the tooth was missing, resulting in a life. In Comparative Example 5, since maleimide was used as a co-crosslinking agent, tearing was reduced, teeth were missing, and life was reached. In Examples 3 and 6, trimethylolpropane trimethacrylate was used for silica reinforcement, so that the adhesiveness to the core and the strength of the teeth were good, and the tear resistance was high, and it was possible to run for 150 hours.

  INDUSTRIAL APPLICABILITY The present invention can be used to improve the transmission force of a V-belt, a V-ribbed belt, a toothed belt, etc. and maintain workability when the transmission force is improved.

It is an example of sectional drawing of the metal mold | die of an example used for the manufacturing method of the urethane belt which is an example of this invention. It is sectional drawing of the belt of a cut edge type which is another example of this invention. It is a conceptual diagram which shows the layout of a running test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Toothed belt 2 Back rubber 3 Adhesive rubber 4 Core wire 5 Tooth cloth 6 Tooth rubber 21 V belt 31 Belt 32 Drive side pulley (Dr pulley)
33 Driven pulley (Dn pulley)

Claims (6)

Hydrogenated nitrile rubber containing unsaturated carboxylic acid metal salt and hydrogenated nitrile rubber and hydrogenated nitrile containing unsaturated carboxylic acid metal salt in rubber composition for belts used for transmission or conveyance comprising hydrogenated nitrile rubber and hydrogenated nitrile rubber The rubber is a matrix rubber, 10 to 60 parts by mass of silica is added to 100 parts by mass of the matrix rubber, 1 to 10 parts by mass of trimethylolpropane methacrylate and 0.2 to 10 parts of organic peroxide as a co-crosslinking agent. A rubber composition for belts, characterized in that a part by mass is added.   The rubber composition for a belt according to claim 1, wherein the matrix rubber is a mixture 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. The rubber composition for a belt according to claim 1 or 2, wherein the amount of silica is 30 to 60 parts by mass with respect to 100 parts by mass of the matrix rubber . In belts used for power transmission or conveyance, consisting of hydrogenated nitrile rubber containing unsaturated carboxylic acid metal salt and hydrogenated nitrile rubber , hydrogenated nitrile rubber and hydrogenated nitrile rubber containing unsaturated carboxylic acid metal salt as matrix It is made of rubber, 10 to 60 parts by mass of silica is added to 100 parts by mass of the matrix rubber, 1 to 10 parts by mass of trimethylolpropane methacrylate is used as a co-crosslinking agent, and the rubber is crosslinked with an organic peroxide. A characteristic rubber belt.   The rubber belt according to claim 4, wherein the matrix rubber is obtained by mixing 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. The rubber belt according to claim 4 or 5, wherein the addition amount of silica is 30 to 60 parts by mass with respect to 100 parts by mass of the matrix rubber .

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