JP4792053B2 - Aqueous treatment agent applied to reinforcing fibers - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based treatment agent capable of forming a toothed belt excellent in heat resistance and bending fatigue resistance and imparting good working circumstance in a film forming process. <P>SOLUTION: The water-based treatment agent is applied to reinforcing fibers and comprises a rubber latex and a vulcanization agent as main ingredients. The amount of the vulcanization agent is in the range of 10-100 pts.mass based on 100 pts.mass rubber and the rubber is a carboxyl modified one. <P>COPYRIGHT: (C)2008,JPO&amp;INPIT

Description

  The present invention relates to an aqueous treatment agent applied to reinforcing fibers.

In order to improve the durability and wear resistance of the toothed belt, generally, a fiber called a tooth cloth is embedded on the surface of the tooth portion. The use of the tooth cloth improves the durability of the teeth and the wear resistance of the rubber surface. For the tooth cloth, a fiber woven in a sheet shape is usually used. And in order to improve adhesiveness with the matrix rubber | gum of a belt main body, the surface of a tooth cloth is normally processed with various processing agents. For example, a tooth cloth is disclosed that is treated with a mixed solution of a condensate of resorcinol and formaldehyde and a latex and then impregnated with a rubber paste containing a filler such as carbon (Patent Document 1). Further, a tooth cloth treated with a rubber composition in which hydrogenated nitrile rubber is mixed with N, N′-m-phenylene dimaleimide is disclosed (Patent Document 2).
JP 7-217705 A JP-A-7-259928

  However, the conventional tooth cloth treated with the above treatment agent has relatively high adhesion in a static test, but when running as a belt for a long time, the integrity of the tooth cloth and the belt portion is poor, Cracks are likely to occur between the matrix rubber. As a result, there is a problem that defects such as chipping of the tooth portion are liable to occur. Moreover, when processing a tooth cloth using the conventional processing agent which uses an organic solvent as a solvent, the environmental measure in a manufacturing process was required.

  In consideration of such a situation, the present invention has an object to provide an aqueous treatment agent that can form a toothed belt excellent in heat resistance and bending fatigue resistance and has a good working environment in the film forming process. To do.

In order to achieve the above object, the aqueous treatment agent of the present invention is an aqueous treatment agent applied to a reinforcing fiber, and is mainly composed of a carboxyl-modified hydrogenated nitrile rubber latex and a maleimide vulcanizing agent. And the amount of the maleimide vulcanizing agent is in the range of 10 to 100 parts by mass with respect to 100 parts by mass of the carboxyl-modified hydrogenated nitrile rubber, and the components of the aqueous treatment agent are dispersed or dissolved in an aqueous solvent. The aqueous solvent contains water in a proportion of 50% by mass or more, and the carboxyl-modified hydrogenated nitrile rubber and the maleimide vulcanizing agent are added in total, and the aqueous treatment removes the solvent and the dispersion medium. It is 50 mass% or more of the total components of the agent, and does not contain resorcin-formaldehyde condensate.

  According to the present invention, a reinforcing sheet capable of forming a toothed belt excellent in heat resistance and bending fatigue resistance can be obtained. Since the aqueous treatment agent of the present invention usually does not contain substances with a large environmental load such as organic solvents, formaldehyde and ammonia, the working environment in the film forming process is good.

  Hereinafter, embodiments of the present invention will be described in detail.

(Toothed belt reinforcing sheet)
A toothed belt reinforcing sheet (tooth cloth) formed using the aqueous treatment agent of the present invention includes a fiber sheet and a coating film formed on the fiber sheet. The film is a film formed by applying an aqueous treatment agent (aqueous adhesive) containing a first rubber latex and a vulcanizing agent as main components to a fiber sheet and drying it. An aqueous processing agent contains a vulcanizing agent in the range of 10-100 mass parts with respect to 100 mass parts of 1st rubber | gum (solid content).

  The aqueous treatment agent preferably further contains carbon black. By adding carbon black, the manufacturing cost of the reinforcing sheet can be reduced. Moreover, the cohesive force of the coating component can be increased by carbon black, and the heat resistant adhesion between the reinforcing sheet and the tooth rubber can be effectively increased. In addition to carbon black, organic / inorganic fillers such as silica and talc may be blended, but carbon black is preferred in terms of reinforcing effect and stability.

  The aqueous treatment agent contains a first rubber latex and a vulcanizing agent as main components. The total amount of the first rubber (solid content) and the vulcanizing agent is 50% by mass or more (for example, 70% by mass or more) of the total components (excluding the solvent and dispersion medium) of the aqueous treatment agent.

  Examples of the vulcanizing agent include quinone dioxime vulcanizing agents such as p-quinonedioxime, methacrylate vulcanizing agents such as lauryl methacrylate and methyl methacrylate, DAF (diallyl fumarate), DAP (diallyl phthalate), and TAC ( Allyl vulcanizing agents such as triallyl cyanurate) and TAIC (triallyl isocyanurate), bismaleimide, phenylmaleimide and diphenylmethane-4,4′-bismaleimide (N, N ′-(4,4′-diphenylmethane) And maleimide vulcanizing agents such as bismaleimide), aromatic or aliphatic organic diisocyanates, aromatic nitroso compounds, or sulfur. These vulcanizing agents may be used alone or in combination of two or more. These vulcanizing agents are selected in consideration of the type of rubber.

  Among these, it is preferable to use at least one vulcanizing agent selected from maleimide vulcanizing agents, organic diisocyanates, and aromatic nitroso compounds. By using these, the adhesiveness between the reinforcing sheet and the matrix rubber can be specifically increased. In particular, diphenylmethane-4,4'-bismaleimide has good stability when dispersed in water, has a high crosslinking effect, and has high heat resistance after vulcanization.

  The first rubber is a carboxyl-modified rubber. By using a carboxyl-modified rubber, the adhesiveness can be enhanced. There is no particular limitation on the carboxyl-modified rubber, and for example, the following rubbers can be used. Examples of the first rubber latex contained in the aqueous treatment agent include carboxyl-modified butadiene / styrene copolymer latex, dicarboxylated butadiene / styrene copolymer latex, and carboxyl-modified vinylpyridine / butadiene.・ Styrene terpolymer latex, carboxyl-modified chloroprene latex, carboxyl-modified butadiene rubber latex, carboxyl-modified chlorosulfonated polyethylene latex, carboxyl-modified nitrile rubber latex (carboxyl-modified acrylonitrile Butadiene copolymer latex), carboxyl-modified hydrogenated nitrile rubber latex, and the like can be used. These rubber latexes can be used alone or in combination.

  The aqueous treatment agent may contain other substances such as peroxides, plasticizers, anti-aging agents, metal oxides, and stabilizers.

  In the aqueous treatment agent, the above components are dispersed or dissolved in an aqueous solvent. If it is an aqueous solvent, it is easy to handle, the concentration control of the above components is easy, and the environmental load is significantly reduced compared to organic solvents. The aqueous solvent contains water as a main component (50% by mass or more and preferably 65% or more), for example, substantially consisting of water, but may contain a lower alcohol or the like. The aqueous solvent preferably contains substantially no organic solvent other than lower alcohol, formaldehyde, and ammonia.

  An aqueous processing agent contains a vulcanizing agent in the ratio of 10-100 mass parts with respect to 100 mass parts of 1st rubber | gum. In this case, it is preferable that an aqueous processing agent contains carbon black in the ratio of 5-70 mass parts with respect to 100 mass parts of 1st rubber | gum. The aqueous treatment agent preferably contains the vulcanizing agent in the range of 20 to 75 parts by mass, and more preferably in the range of 30 to 75 parts by mass with respect to 100 parts by mass of the first rubber. By using such an aqueous treatment agent, high adhesive force can be obtained even with a single layer coating. In this case, it is preferable that an aqueous processing agent contains carbon black in 10-30 mass parts with respect to 100 mass parts of 1st rubber | gum.

  The relationship between the amount of rubber and the amount of vulcanizing agent in the aqueous treatment agent is particularly important. The vulcanizing agent in the treatment agent diffuses to the matrix rubber side when both the first rubber and the matrix rubber are vulcanized, and reinforces not only the coating but also the vulcanization of the matrix rubber. As a result, high adhesive strength and integrity can be obtained. Therefore, if the amount of the vulcanizing agent is too small, vulcanization of the coating itself can be achieved to some extent, but since the reinforcing effect on the matrix rubber side cannot be obtained, the integrity between the reinforcing sheet and the matrix rubber becomes insufficient, Sufficient adhesive strength cannot be obtained. On the other hand, when there are too many vulcanizing agents, the hardness of the coating increases and the strength of the belt when the toothed belt is bent tends to decrease.

  Examples of preferable combinations of the first rubber and the vulcanizing agent include combinations such as carboxyl-modified nitrile rubber and maleimide vulcanizing agent, carboxyl-modified hydrogenated nitrile rubber and maleimide vulcanizing agent. By using these combinations, the adhesion between the reinforcing sheet and the matrix rubber can be particularly enhanced.

  The fiber sheet is a sheet composed of reinforcing fibers. The reinforcing fiber is not particularly limited as long as it enhances the shape stability and strength of the reinforcing sheet. For example, polyvinyl alcohol fibers such as glass fibers and vinylon fibers, polyester fibers, polyamide fibers such as nylon and aramid (aromatic polyamide), carbon fibers, or polyparaphenylenebenzoxazole (PBO) fibers can be used. A preferable example of the fiber sheet is a nylon fiber knitted into a sheet shape. These fibers may be used alone or in combination of two or more. The form of the fiber sheet is not limited as long as it is sheet-like, and may be a woven fabric or a non-woven fabric.

  The coating on the fiber sheet contains unvulcanized rubber and a vulcanizing agent. The amount of the coating is not particularly limited, and in one example, the ratio of the coating to the entire reinforcing sheet may be in the range of 5 to 30% by mass (for example, 6 to 15% by mass).

  The reinforcing sheet of the present invention includes a coating for covering the fiber sheet, and the coating contains a vulcanizing agent in a high ratio. When the reinforcing sheet and the matrix rubber of the toothed belt are integrated, the vulcanizing agent diffuses into the matrix rubber and enhances the integrity of the reinforcing sheet and the matrix rubber. Therefore, according to the reinforcing sheet of the present invention, it is possible to obtain a toothed belt with little damage to the teeth even when used for a long time. Moreover, since the processing agent used for manufacture of this reinforcing sheet uses an aqueous solvent, environmental load is small and handling at the time of manufacture is easy. In addition, the reinforcing sheet of the present invention is usually easy to manufacture because the coating is a single layer. A method for manufacturing the reinforcing sheet will be described below.

(Manufacturing method of toothed belt)
The manufacturing method of this invention is a manufacturing method of a toothed belt provided with a belt part and the tooth part protruded from this belt part. The toothed belt manufactured by this method is the toothed belt of the present invention.

  In this manufacturing method, an aqueous treatment agent containing a first rubber latex and a first vulcanizing agent is applied to a fiber sheet and dried to obtain a fiber sheet and a film formed on the fiber sheet. A step (first step) of forming a reinforcing sheet. By this step, the reinforcing sheet of the present invention is obtained. Since the material of the reinforcing sheet such as the fiber sheet and the aqueous treatment agent and the composition ratio of the material have been described above, redundant description will be omitted. For example, the vulcanizing agent described above can be applied to the first vulcanizing agent.

  The method for forming the film is not particularly limited. For example, a film can be formed by immersing a fiber sheet in a bath containing an aqueous treatment agent, pulling it up, and then removing the solvent through a drying furnace. There is no particular limitation on the drying method, and for example, drying by heating can be applied. However, in the first step, drying is performed under conditions where the vulcanization of the first rubber in the aqueous treatment agent does not proceed easily. For example, drying may be performed by exposure for 0.1 to 2 minutes in an atmosphere of 80 to 160 ° C. The coating film formed in the first step contains unvulcanized rubber and a vulcanizing agent.

  Next, in a state where the rubber composition and the reinforcing sheet that are the material of the tooth portion are in close contact with each other, by simultaneously vulcanizing the first rubber and the second rubber (rubber in the rubber composition), The surface of the tooth portion is reinforced with a reinforcing sheet (second step). The rubber composition contains a second rubber and a second vulcanizing agent as main components. The heating conditions for vulcanization are selected according to the type and amount of rubber and vulcanizing agent. In the second step, usually, the first rubber and the second rubber are heated and applied in a state where the rubber composition, which is the material of the belt main body (belt portion and tooth portion), and the reinforcing sheet are in close contact with each other. Sulfurate. The rubber composition may be molded into a predetermined shape before vulcanization or may be molded during vulcanization.

  The second rubber (matrix rubber) is selected according to the characteristics required for the toothed belt. As the second rubber, for example, the rubber described for the first rubber can be applied. The first rubber and the second rubber may be the same or different, but by making them the same rubber, the integrity of the reinforcing sheet and the belt body can be enhanced. The rubber composition is a rubber that is unvulcanized or not completely vulcanized, and includes additives such as a vulcanizing agent. There is no limitation in particular in a vulcanizing agent, The vulcanizing agent mentioned above and a well-known vulcanizing agent are applicable.

  The reinforcing sheet is usually formed on the surface of the belt main body (belt portion and tooth portion) on the entire side where the tooth portion is formed, that is, the surface of the convex portion including the tooth portion and the tooth portion. Placed to cover the surface of no recesses and reinforce those surfaces. There is no particular limitation on the method for integrating the reinforcing sheet and the toothed belt, and a known method can be applied. In an example method, a reinforcing sheet, a reinforcing cord, and a sheet of a rubber composition, which is a material of the belt body, are wound around a cylindrical mold in which a recess is formed at a position corresponding to a tooth part, Heat and pressurize. In this method, a sheet of a rubber composition is molded to form a tooth portion and a belt portion, and a reinforcing sheet is disposed on the surfaces thereof. During the heating and pressurization, the first rubber and the second rubber are vulcanized simultaneously. Even if a reinforcing sheet is further arranged on the surface opposite to the tooth portion, the rubber composition sheet has a two-layer structure, or a reinforcing sheet is further arranged between the two-layer structures. Good.

  A sectional view of an example of a toothed belt manufactured by the manufacturing method of the present invention is schematically shown in FIG. The toothed belt 10 of FIG. 1 includes a belt body 11 and a reinforcing sheet 12. The belt body 11 includes a belt portion 13 and a plurality of tooth portions 14 protruding from the belt portion 13 at regular intervals. The reinforcing sheet 12 is disposed so as to cover the surface of the belt body 11 on the side where the tooth portions 14 are formed. A reinforcing cord 15 is embedded in the belt portion 13. For example, a strand covered with a film containing rubber can be applied to the reinforcing cord 15. The strand can be formed of reinforcing fibers such as glass fibers and resin fibers. The coating of the reinforcing cord 15 can be formed, for example, with the above-described aqueous adhesive. The rubber in the coating of the reinforcing cord 15 is also preferably vulcanized simultaneously with the first rubber and the matrix rubber.

  In the manufacturing method of the present invention, since the first rubber of the reinforcing sheet and the second rubber constituting the tooth portion are simultaneously vulcanized, the integrity of the reinforcing sheet and the belt main body can be dramatically increased. it can. In this method, since the vulcanizing agent contained in the coating on the reinforcing sheet diffuses into the second rubber, the integrity between the reinforcing sheet and the belt body can be particularly enhanced. This effect is particularly high when the aqueous treatment agent contains a vulcanizing agent in the range of 30 to 75 parts by mass with respect to 100 parts by mass of the first rubber.

  According to the method of the present invention, a toothed belt having high heat resistance, high integrity even when running for a long time, and excellent bending fatigue resistance can be obtained.

  Examples of the present invention will be described below.

Example 1
An aqueous treatment agent shown in (1) of Table 1 was applied to the nylon fiber knitted into a sheet, and dried at 120 ° C. for 1 minute to form a toothed belt reinforcing sheet.

  On the other hand, the reinforcing cord was formed by treating the glass fiber with the RFL treatment liquid of (2) in Table 2, that is, a mixture of resorcin-formaldehyde condensate and hydrogenated nitrile rubber latex. The reinforcing sheet and the reinforcing cord were heat-treated at 170 ° C. for 30 minutes together with the rubber composition (matrix rubber) having the composition shown in Table 3 to vulcanize the reinforcing sheet rubber and the matrix rubber simultaneously.

  In this manner, a toothed belt in which the reinforcing sheet is disposed on the tooth side surface and the reinforcing cord is embedded in the belt portion was manufactured.

( Reference Example 1 )
A toothed belt was produced under the same conditions as in Example 1 except that the aqueous treatment agent shown in (2) of Table 1 was used instead of the aqueous treatment agent of (1) in Table 1.

( Reference Example 2 )
A toothed belt was produced under the same conditions as in Example 1 except that the aqueous treatment agent shown in (1) of Table 1 was used instead of the aqueous treatment agent of (1) in Table 1.

(Comparative Example 1)
Instead of the carboxylated hydrogenated nitrile rubber latex, an aqueous treatment agent was prepared which was the same as the aqueous treatment agent of (1) in Table 1 except that a non-carboxylized hydrogenated nitrile rubber latex was used. And the toothed belt was produced on the same conditions as Example 1 except having used this aqueous processing agent instead of the aqueous processing agent of (1) of Table 1.

(Comparative Example 2)
A toothed belt was produced under the same conditions as Example 1 except that the aqueous treatment agent shown in (1) of Table 2 was used instead of the aqueous treatment agent of (1) in Table 1.

(Comparative Example 3)
A toothed belt was produced under the same conditions as in Example 1 except that the RFL treatment solution shown in (2) of Table 2 was used instead of the aqueous treatment agent of (1) in Table 1.

For the toothed belts of Examples , Reference Examples and Comparative Examples, a peel test between the reinforcing sheet and the matrix rubber was performed, and the adhesive strength between them was measured and the fracture mode was observed. Further, these toothed belts were subjected to a bending running test for 100 hours under an atmosphere of 140 ° C., and it was confirmed whether or not the reinforcing sheet was peeled off after running. Further, the strength of the toothed belt before and after the running test was measured, and the ratio of the strength after the running test to the strength before the running test, that is, the strength retention rate was calculated. The evaluation results are shown in Table 4.

  As shown in Table 4, the toothed belt of the example had high adhesive strength between the reinforcing sheet and the matrix rubber. Further, the toothed belt of the example did not generate cracks in the running test and had a high strength retention. In addition, when the carboxyl-modified rubber latex was used, the adhesive strength between the reinforcing sheet and the matrix rubber was particularly high.

  The embodiments of the present invention have been described above by way of examples, but the present invention is not limited to the above-described embodiments, and can be applied to other embodiments based on the technical idea of the present invention.

  The present invention can be applied to an aqueous treatment agent applied to reinforcing fibers.

It is sectional drawing which shows typically an example of the toothed belt manufactured with the manufacturing method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Toothed belt 11 Belt main body 12 Reinforcing sheet 13 Belt part 14 Tooth part 15 Reinforcing cord

Claims (4)

An aqueous treatment agent applied to the reinforcing fiber,
Containing a carboxyl-modified hydrogenated nitrile rubber latex and a maleimide vulcanizing agent as main components,
The amount of the maleimide vulcanizing agent with respect to 100 parts by mass of the carboxyl-modified hydrogenated nitrile rubber is in the range of 10 to 100 parts by mass,
The constituents of the aqueous treatment agent are dispersed or dissolved in an aqueous solvent,
The aqueous solvent contains water in a proportion of 50% by mass or more,
The total amount of the carboxyl-modified hydrogenated nitrile rubber and the maleimide vulcanizing agent is 50% by mass or more of the total components of the aqueous treatment agent excluding the solvent and the dispersion medium,
An aqueous treatment agent that does not contain resorcin-formaldehyde condensate.   The aqueous treatment agent according to claim 1, further comprising carbon black.   The aqueous treating agent according to claim 1, wherein the vulcanizing agent is diphenylmethane-4,4'-bismaleimide. The aqueous processing agent of any one of Claims 1-3 whose said aqueous solvent is water.

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