JP2003343658A - Toothed belt - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toothed belt with a low impact on the environment. <P>SOLUTION: In the toothed belt 10, a belt tooth side surface of a toothed belt body 11 made of ethylene propylene rubber is covered with reinforcing cloth 13. The reinforcing cloth 13 comprises cloth applied with a treatment where the surface on the toothed belt body 11 side is coated with rubber paste made of ethylene propylene rubber and dried. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toothed belt in which a belt tooth side surface of a toothed belt main body is covered with a reinforcing cloth.

[0002]

2. Description of the Related Art Small precision toothed belts made of rubber are used in precision equipment such as OA (office automation) equipment. As such a toothed belt, one made of chloroprene rubber is most widely used.

[0003]

However, in recent years,
There is an increasing demand for products with a low environmental load such as dehalogenation, and the toothed belt is also changed from one made of chloroprene rubber containing chlorine atoms that are halogens in the molecule to one made of non-halogen polymer rubber. Is desired.

The present invention has been made in view of the above points, and an object of the present invention is to provide a toothed belt having a small load on the environment.

[0005]

According to the present invention, both the toothed belt main body and the rubber glue adhered to the surface of the reinforcing cloth on the toothed belt main body side are ethylene / propylene rubbers.

Specifically, the present invention is a toothed belt in which a belt tooth side surface of a toothed belt main body made of ethylene / propylene rubber is covered with a reinforcing cloth, and the reinforcing cloth is the toothed belt. With ethylene on the surface corresponding to the belt body side
It is characterized in that it is made of a cloth which is coated with a rubber paste made of propylene rubber and then dried.

According to the above construction, the toothed belt main body is made of ethylene / propylene rubber, and the rubber glue coated on the surface of the cloth constituting the reinforcing cloth corresponding to the toothed belt main body side is also ethylene. -Made of propylene rubber, all of which are the same type of ethylene-propylene rubber, so the adhesiveness between the toothed belt body and the reinforcing cloth is excellent, and
Since at least the toothed belt body and the rubber paste are dehalogenated, the load on the environment is small.

Here, the ethylene propylene rubber is a copolymer rubber of ethylene and propylene, specifically, EPDM and EPM.

[0009] Further, the rubber glue is a predetermined mixture of ethylene
It refers to a propylene rubber composition dissolved in a solvent such as toluene or methyl ethyl ketone (MEK).

In the present invention, the above-mentioned rubber paste may be white or light-colored.

In a precision instrument application, since it is a bad image to stain the surroundings, it is disliked that the black rubber exuded from the grain of the reinforcing cloth falls off as rubber powder. In addition, the rubber paste attached to the cloth constituting the reinforcing cloth suppresses the exudation of rubber, and even if the rubber exudes from the grain of the cloth, it is mainly of a white to light color type, so it is used as rubber powder. It doesn't give a bad image of polluting the surroundings even if it falls.

In the present invention, the cloth constituting the above-mentioned reinforcing cloth is dipped in an aqueous solution of resorcin-formalin latex (hereinafter referred to as "RFL") whose latex component is an epoxidized polyethylene latex before the treatment with the rubber paste. It may be subjected to a treatment of heating after heating.

According to the above constitution, the epoxidized polyethylene latex having the polyethylene component is used as the latex of the RFL aqueous solution, the polyethylene component is highly compatible with the ethylene / propylene rubber having a low polarity, and the epoxy component is the rubber. Since it easily reacts with chemicals,
The adhesiveness between the toothed belt body and the reinforcing cloth can be further enhanced.

In this case, in the present invention, the solid content concentration of the RFL aqueous solution may be 10% by mass or more and 40% by mass or less.

According to the above construction, it is possible to obtain a sufficient amount of adhesion of RFL to the cloth constituting the reinforcing cloth so as to obtain a high adhesive force between the toothed belt body and the reinforcing cloth. Here, when the solid content concentration is lower than 10% by mass, the amount of RFL attached to the cloth constituting the reinforcing cloth is small, and the adhesive force between the toothed belt body and the reinforcing cloth is slightly inferior. When the solid content concentration is higher than 40% by mass, RFL is applied to the fabric constituting the reinforcing fabric.
Becomes too hard to form the belt teeth by pressing the cloth with rubber at the time of forming the belt, and the rubber easily exudes from the cloth at that time.

Further, in the toothed belt of the present invention, the cloth treated with the rubber glue and the resorcin / formalin / latex aqueous solution constituting the above-mentioned reinforcing cloth has a direction corresponding to the longitudinal direction of the belt in an atmosphere of 100 ° C. The force required to generate 50% tensile strain may be 5 N or less per 3 cm of cloth width.

According to the above construction, when the belt teeth are formed at the time of forming the belt, the cloth serving as the reinforcing cloth easily extends in the longitudinal direction of the belt, so that the resistance against the pressing of the rubber is small and the formability of the belt teeth is improved. In addition to being excellent, it is possible to effectively suppress the exudation of rubber from the texture.

[0018]

As described above, according to the present invention,
The toothed belt body also constitutes the reinforcing cloth.The rubber glue attached to the surface corresponding to the toothed belt body side of the cloth is also made of ethylene / propylene rubber, so the adhesiveness between the toothed belt body and the reinforcing cloth is excellent, Moreover, since at least the toothed belt body and the rubber paste can be dehalogenated, the load on the environment is small.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a toothed belt 10 according to an embodiment of the present invention. This toothed belt 10 has a belt width of about 5 mm and a belt circumferential length of 250 mm incorporated in precision equipment.
It is small in size.

This toothed belt 10 is a toothed belt body 1
1, a tooth rubber portion 11a forming belt teeth, which is provided inside the belt at a predetermined pitch in the longitudinal direction, and a back rubber portion 11b outside the belt are integrally formed. Further, the tooth rubber portion 11a and the back rubber portion 1 of the toothed belt main body 11
Between the cords 1b and 1b, the cords 12 are provided in a spiral shape with a pitch formed in the belt width direction so as to extend substantially in the belt longitudinal direction. Further, a reinforcing cloth 13 that covers the surface of the toothed belt main body 11 on the belt tooth side, which is the inner peripheral side of the belt, is provided via a rubber glue layer 13a.

The toothed belt body 11 is formed of ethylene-propylene rubber (EPM, EDDM) mixed with a rubber chemical such as carbon black.

The core wire 12 is obtained by gathering a plurality of strands which have been heated after being immersed in an RFL aqueous solution whose latex component is a non-halogen latex component in a glass fiber bundle and twisted them. It is composed of.

The reinforcing cloth 13 is made of a twill fabric.
In this twill fabric, the yarn extending in the longitudinal direction of the belt is a stretchable yarn in which stretchable fibers such as urethane fibers are wound with 6,6-nylon fibers, and the yarn extending in the belt width direction is a twisted yarn such as 6,6-nylon fibers. And has extensibility in the direction corresponding to the longitudinal direction of the belt. Further, this twill fabric is subjected to a treatment of being heated after being immersed in an RFL aqueous solution in which the latex is an epoxidized polyethylene latex and having a solid content concentration of 10 to 40% by mass. The surface of the belt main body 11 is coated with a white or light-colored rubber paste made of ethylene / propylene rubber and then dried to form a layer of the rubber paste. Twill fabrics that have been subjected to these treatments are 100
The force required to generate 50% tensile strain in the direction corresponding to the longitudinal direction of the belt in an atmosphere of ° C is 5 N or less per 3 cm of cloth width.

Next, a method of manufacturing the toothed belt 10 will be described.

First, an unvulcanized rubber sheet of ethylene / propylene rubber to be the toothed belt body 11, a core wire 12 and a twill fabric to be the reinforcing cloth 13 are prepared. Here, as described above, the core wire 12 is produced by collecting a plurality of strands obtained by subjecting the glass fiber bundle to the immersion in the RFL aqueous solution and then heating it, and twisting them together. Further, the twill fabric is subjected to a heating treatment after being immersed in an RFL aqueous solution whose latex is an epoxidized polyethylene latex and has a solid content concentration of 10 to 40% by mass. The surface is coated with a white or light-colored rubber paste made of ethylene / propylene rubber and then dried.

Next, a cylindrical mold in which concave grooves extending in the axial direction are formed on the peripheral surface of the mold at equal intervals in the circumferential direction is covered with a twill fabric. At this time, the extending direction of the twill fabric is made to coincide with the circumferential direction of the cylindrical mold (belt longitudinal direction).

Then, the core wire 1 is placed on the twill fabric on the cylindrical mold.
2 is spirally wound, and an unvulcanized rubber sheet is further wound on it.

Subsequently, the cylindrical mold set with the twill fabric, the core wire 12 and the unvulcanized rubber sheet is placed in a vulcanizing pot and heated and pressed. At this time, the rubber flows toward the cylindrical mold by heating and pressing, and particularly in the groove portion, the twill fabric is stretched along the surface of the groove by the pressing of the rubber to form the belt teeth. Further, the toothed belt main body 11 is formed, and a cylindrical slab in which the cored wire 12 and the twill fabric (reinforcing cloth 13) are integrated is formed. In the twill fabric, a layer of rubber glue formed on the surface of the twill fabric is interdiffused with the rubber forming the toothed belt body 11 at the interface to form a rubber glue layer 13 a between the toothed belt body 11 and the reinforcing cloth 13. To do.

Then, the cylindrical mold is taken out from the vulcanization kettle,
Remove the slab from the cylindrical mold.

Finally, the back surface of the slab is polished to make it uniform in thickness, and then sliced into a predetermined width.

According to the toothed belt 10 having the above structure, the toothed belt main body 11 is formed of ethylene / propylene rubber, and the surface of the twill fabric constituting the reinforcing cloth 13 corresponding to the toothed belt main body 11 side. The rubber paste layer 13a formed by the rubber paste coated on the base is also formed of ethylene / propylene rubber, and the core wire 12 is treated with a non-halogen latex RFL aqueous solution, and the entire belt is Since it is dehalogenated, the load on the environment is extremely small.

The toothed belt body 11 also includes the rubber glue layer 1
3a is also formed of ethylene / propylene rubber, and the twill fabric constituting the reinforcing cloth 13 is subjected to a heating treatment after being immersed in an RFL aqueous solution whose latex component is an epoxidized polyethylene latex. The component is highly compatible with ethylene / propylene rubber having low polarity, the epoxy component easily reacts with rubber chemicals, etc. Furthermore, the solid content concentration of the RFL aqueous solution is 10 to 40% by mass, which is suitable for twill fabric. Therefore, it is possible to obtain an extremely high adhesive force between the toothed belt main body 11 and the reinforcing cloth 13.

Further, in precision equipment applications, since it is a bad image to stain the surroundings, it is disliked that the black rubber exuded from the grain of the reinforcing cloth 13 falls off as rubber powder. Since a light-colored material is used, the rubber glue layer 13a basically suppresses the exudation of rubber, but even if the rubber exudes from the texture, it is mainly of a white or light-colored type. For,
Even if it falls off as rubber powder, it does not give a bad image of polluting the surrounding area.

Further, in the twill fabric treated with the rubber paste and the resorcin / formalin / latex aqueous solution constituting the reinforcing cloth 13, a tensile strain of 50% is generated in a direction corresponding to the longitudinal direction of the belt under 100 ° C. atmosphere. The force required for is 5 N or less per cloth width of 3 cm, and when forming the belt teeth at the time of forming the belt, the twill fabric that serves as the reinforcing cloth 13 easily extends in the longitudinal direction of the belt, so that the resistance against the pressing of the rubber is small, The belt teeth are excellent in moldability, and the exudation of rubber from the texture can be effectively suppressed.

In the above embodiment, the core wire 12 is made of glass fiber, but it is not limited to this and may be aramid fiber core or polyester fiber core.

Further, in the above embodiment, the twill fabric is used as the fabric to be the reinforcing fabric 13, but the fabric is not particularly limited to this, and other woven fabric such as plain fabric, knitted fabric or non-woven fabric may be used. Good.

[0038]

Examples (Adhesion test) <Test sample> -Example 1-The yarn extending in one direction is a stretchable yarn in which 6,6-nylon fiber is wound around urethane fiber, and the yarn extending in the other direction is 6,6. -A twill fabric, which is a twisted yarn of nylon fiber, is dipped in an RFL aqueous solution having a latex component of epoxidized polyethylene latex and a solid content concentration of 40% by mass, and then subjected to a heating treatment, which is then unvulcanized. EPD
Example 1 was a block-shaped test piece for a peel test having a width of 2.54 cm which was placed on the surface of M and press-molded.

Example 2-Example 2 has the same structure as Example 1 except that the solid content concentration of the RFL aqueous solution was 10% by mass.

Example 3-Example 3 has the same structure as in Example 1 except that the solid content concentration of the RFL aqueous solution was 5% by mass.

Example 4-Example 4 has the same structure as in Example 2 except that the latex component of the RFL aqueous solution is based on vinyl pyridine-styrene-butadiene rubber (SBR).

Example 5-A twill fabric in which the yarn extending in one direction is a stretchable yarn in which 6,6-nylon fibers are wound around urethane fibers and the yarn extending in the other direction is a twisted yarn of 6,6-nylon fibers. On the other hand, after immersing in a resorcin-formalin (RF) aqueous solution having a solid content concentration of 2.6 mass% and then heating it, it is placed on the surface of unvulcanized chloroprene rubber (CR). A block-shaped test piece for a peel test having a width of 2.54 cm was used as Example 5.

Example 6-A twill fabric in which the yarn extending in one direction is a stretchable yarn in which 6,6-nylon fibers are wound around urethane fibers and the yarn extending in the other direction is a twisted yarn of 6,6-nylon fibers. On the other hand, the width of the resin is immersed in a resorcinol-formalin (RF) aqueous solution having a solid concentration of 2.0% by mass and then heated, and then placed on the surface of unvulcanized EPDM and press-formed. A 2.54 cm block test piece for peeling test was used as Example 6.

<Test Method> Peel Test of Examples 1 to 6 The force required for peeling the woven fabric from the rubber in the longitudinal direction at room temperature was measured for the melting test pieces.

<Test Results> The test results are shown in Table 1.

[0046]

[Table 1]

According to a comparison between Example 2 and Example 4, when the adherend rubber is EPDM, it is preferable that the latex component of the RFL aqueous solution is an epoxidized polyethylene latex and the latex component of the RFL aqueous solution is a vinylpyridine-SBR latex. It can be seen that the adhesive force is more than twice as high as
It is considered that this is because the polyethylene component of the epoxidized polyethylene latex is highly compatible with ethylene / propylene rubber having a low polarity, and the epoxy component easily reacts with a rubber chemical or the like.

According to the comparison of Examples 1 to 3, the higher the solid content concentration of the RFL aqueous solution in which the latex component is the epoxidized polyethylene latex, that is, the R on the twill fabric is
It can be seen that the greater the amount of FL attached, the higher the adhesive strength. Example 5 assumes that a twill fabric serving as a reinforcing cloth is dipped in an RF aqueous solution and heated, and a conventional toothed belt in which the toothed belt main body is formed of CR is assumed. RFL for higher adhesive strength
It is sufficient if the solid content concentration of the aqueous solution is 10% by mass or more.

According to the comparison between Example 5 and Example 6, the twill fabric is R
It can be seen that the adhesive force is reduced to half or less when the adhered rubber is changed from CR to EPDM simply by immersing it in the F aqueous solution and heating it.

(Bleeding Test) <Test Sample> A yarn extending in one direction is a stretchable yarn in which 6,6-nylon fibers are wound around urethane fibers, and a yarn extending in the other direction is a twisted yarn of 6,6-nylon fibers. RF in which the latex component is epoxidized polyethylene latex and the solid content concentration is 10 mass% for the twill fabric
After being immersed in the L aqueous solution and then subjected to a heating treatment, four types were prepared in which the surface corresponding to the belt body side was coated with a rubber paste composed of ethylene / propylene rubber. The four kinds of twill fabrics have different treatment conditions from each other, and the force required to generate 50% tensile strain in the direction corresponding to the belt longitudinal direction in an atmosphere of 100 ° C. is 4. 2N, 5.3N, 7.0N and 14.2N.

Toothed belts formed by using the respective twill fabrics were made Examples 7 to 10 in order.

<Test Method> The exudation of rubber on the belt tooth side surface of each toothed belt of Examples 7 to 10 was visually evaluated.
In the evaluation, "◎" indicates that there is no exudation, "○" indicates that the exudation is inconspicuous, "△" indicates that the exudation can be confirmed with the naked eye, and "X" indicates that the exudation is clear. There are many,

<Test Results> Table 2 shows the test results.

[0054]

[Table 2]

According to the table, it can be seen that the exudation is suppressed as the force required to generate 50% tensile strain in the direction corresponding to the longitudinal direction of the belt in the atmosphere of 100 ° C. is smaller. This is because when the belt teeth are formed at the time of belt molding, the twill fabric that becomes the reinforcing fabric is pressed by the flow of rubber and easily extends in the belt longitudinal direction, but if the force required to extend the twill fabric is large, While the rubber receives resistance from the twill fabric and tries to exude from the texture, when the force required to stretch the twill fabric is small, the twill weave becomes a reinforcing fabric when forming belt teeth during belt molding. It is considered that this is because the object easily extends in the longitudinal direction of the belt, so that the resistance against the pressing of the rubber is small, which effectively suppresses the exudation of the rubber from the texture.

[Brief description of drawings]

FIG. 1 is a side view of a toothed belt according to an embodiment of the present invention.

[Explanation of symbols]

10 toothed belt 11 Toothed belt body 11a Tooth rubber part 11b Back rubber part 12 cores 13 Reinforcement cloth 13a rubber glue layer

Claims (5)

[Claims] 1. A toothed belt in which a belt tooth side surface of a toothed belt main body made of ethylene / propylene rubber is covered with a reinforcing cloth, wherein the reinforcing cloth corresponds to the toothed belt main body side. A toothed belt comprising a cloth coated with a rubber paste made of ethylene / propylene rubber and then dried. 2. The toothed belt according to claim 1, wherein the rubber paste is white to light colored. 3. The toothed belt according to claim 1, wherein the cloth constituting the reinforcing cloth is a resorcin / formalin / latex aqueous solution whose latex component is an epoxidized polyethylene latex before the treatment with the rubber paste. A toothed belt, characterized in that it is subjected to a treatment of being dipped in and then heated. 4. The toothed belt according to claim 3, wherein the resorcin / formalin / latex aqueous solution has a solid content concentration of 10 to 40% by mass. 5. The toothed belt according to claim 3, wherein the reinforcing cloth is treated with a rubber paste and a resorcin / formalin / latex aqueous solution to form 10
50% in the direction corresponding to the longitudinal direction of the belt under 0 ° C atmosphere
The toothed belt is characterized in that the force required to generate the tensile strain is 5 N or less per 3 cm of cloth width.