JPH03249449A - Fiber reinforced rubber product - Google Patents

Abstract

PURPOSE:To improve both bending fatigue resistance and dimensional stability by making up reinforcing material with flat braid in combination of multiple threads. CONSTITUTION:A toothed belt A is provided with a belt mainframe 4 as a product mainframe which is made up of an extension-portion rubber layer 1, a reinforcement 2 consisting of fiber buried in the rubber layer 1 in parallel and plural tooth portions 3 integrally formed on one side of the rubber layer 1 with rubber of the same material as that of the rubber layer 1, and a tooth cloth 5 is integrally attached to the surface of the tooth portions 3 of the mainframe 4. The reinforcement 2 is made of flat braid 7 in combination of multiple threads and the braid 7 is arrayed in spiral to avoid torsion. There are the kinds of thread, in use such as nonorganic fiber, organic fiber and metallic fiber etc. The braid 7 is given adhesion treatment and drawing treatment in combination of adhesives of epoxy resin or etc. prior to the process that it is buried in the rubber layer 1.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to fiber-reinforced rubber products, and particularly to improvements in reinforcing bodies embedded in the product body.

(Prior Art) Conventionally, rubber products such as belts, tires, and hoses have been required to have properties such as high strength, high modulus of elasticity, high dimensional stability, and high adhesiveness. In order to satisfy this requirement, reinforcing bodies such as reinforcing cords made of fibers and cloth-like materials are embedded in the rubber product body. As this reinforcing body, a twisted yarn formed by twisting a plurality of threads is generally used, and the types thereof can be divided into plied yarn, single twisted yarn, rung twisted yarn, etc. depending on the twisting method. Currently, among the above-mentioned twisted threads, plied threads are most often used for reinforcing bodies of the above-mentioned rubber products.

However, in rubber products whose reinforcement is made of plied yarn, there are parts where the monofilaments strongly contact each other at deep angles within the plied yarn, so this strong contact area can cause premature wear, breakage, or a decrease in strength. However, there was a problem that the bending fatigue resistance deteriorated.

Therefore, as a fiber-reinforced rubber product that has improved the above-mentioned problem (bending fatigue resistance), a product in which the reinforcing body is composed of single-twisted yarn or rung-twisted yarn has been proposed (Japanese Patent Laid-Open No. 59-1
(See Publication No. 9744).

(Problem to be Solved by the Invention) However, as mentioned above, rubber products in which the reinforcing body is composed of single-twisted yarn or rung-twisted yarn have a structure that requires less stretching and dip treatment compared to rubber products in which the reinforcing body is composed of plied yarn. The tensile modulus of elasticity decreases, resulting in a decrease in dimensional stability.

By the way, braided cords have been used since ancient times. Among these braids, round braids have particularly excellent bending fatigue resistance due to their structural characteristics, and are also better than twisted threads in terms of dimensional stability, so they are used in rubber products. It is preferable to use it as a reinforcing body because it can improve both the physical properties of bending fatigue resistance and dimensional stability. However, since the above-mentioned round braided cord is braided into a cylindrical shape and has a hollow part formed inside, the diameter increases, and the amount of bending strain of the rubber product increases when bent, reducing the bending fatigue resistance. There is a tendency to force people to do something. Further, due to its structure, round braided cords have a small modulus of elasticity in the transverse direction, and therefore, there is a problem that deformation becomes large when lateral pressure is applied.

The present invention has been made in view of these points, and its purpose is to improve the bending fatigue resistance and dimensional stability of rubber products by using flat braids among the traditional braids instead of twisted threads. The object of the present invention is to improve both of these aspects, and also to improve non-deformability against lateral pressure.

(Means for Solving the Problem) In order to achieve the above object, the solution of the present invention as set forth in claim (1) is directed to a rubber product in which a reinforcing body made of fibers is embedded in a rubber product body. In this case, the reinforcing body is constituted by a flat braid made of a plurality of threads.

Moreover, in the solution means of the present invention as set forth in claim (2), the flat braids constituting the reinforcing body are arranged in a spiral so that no twisted portion occurs.

(Function) With the above configuration, in the present invention as set forth in claim (1), the reinforcing body made of fibers embedded in the rubber product body is made of a flat braid made of a plurality of threads. Because of its structure, the structural characteristics of flat braided cords are that uniform stress is applied to the monofilaments that make up the yarn.
Flat braided cords have a flat shape without hollow parts like round braided cords, so the amount of bending strain of the rubber product when bent is reduced compared to the case of round braided cords, and therefore the bending fatigue resistance is greatly improved. can be improved. In addition, dimensional stability is also ensured as a structural characteristic of the flat braid. Furthermore, since the flat braided cord after the adhesive dip treatment has a higher modulus of elasticity in the transverse direction than the round braided cord due to its structure, non-deformability against lateral pressure can be improved.

Furthermore, in the present invention as set forth in claim 2, the flat braided cords constituting the reinforcing body are arranged in a spiral so that no twisted portion occurs, so that the above-mentioned effects are reliably maintained.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 shows a toothed belt A as a fiber-reinforced rubber product according to an embodiment of the present invention, and FIG. 3 shows a low-edge V-belt A' also as a fiber-reinforced rubber product. The toothed belt A has an extension rubber layer 1 and an extension rubber layer 1.
A reinforcing body 2 made of fibers embedded in parallel in the above, and a plurality (first Teeth 3.3. (only two shown in the figure). . . . comprises a belt main body 4 as a product main body consisting of the belt main body 4.
A canvas 5 is integrally attached to the surface side of the tooth portion 3.

As a feature of the present invention, the reinforcing body 2 includes a plurality of (three or more) threads 6, 6 . It is composed of a flat braided cord 7 braided with..., and the flat braided cord 7 is
They are arranged in a spiral to avoid twisting.

The yarns 6 may be made of inorganic fibers, organic fibers, metal fibers, etc., and may also be spun yarns made of long fibers and short fibers, or mixed yarns thereof. It may be selected as appropriate depending on the required performance of the attached belt A. Moreover, the number of yarns 6 that constitute the flat braided cord structure is not limited as long as it is three or more. Furthermore, the total denier number of the yarn 6, the monofilament denier number, etc. may be appropriately selected according to the required performance of the toothed bell I-A.

Further, the flat braided cord 7 assembled as described above is made of, for example, epoxy resin, before being embedded in the extension rubber layer 1.
Adhesive treatment and stretching treatment are performed using a combination of adhesives such as isocyanate compounds, ethylene urea compounds, and resorcinol formalin latex (RFL). Note that the adhesive treatment method is to apply the adhesive to the reinforcing body 2.
The dipping method is preferable because it is necessary to uniformly impregnate the flat braided cord 7 constituting the braid.

On the other hand, the above-mentioned low edge V bell) A- is the extended rubber layer]
and a reinforcing body 2 made of fibers embedded in the elongated rubber layer, and a belt main body 4 as a product main body. The components constituting this low edge V-belt A', including the reinforcing body 2, are the same as those for the toothed belt A, so a detailed explanation thereof will be omitted. do.

Next, a bending fatigue test was conducted on the toothed belt A according to the present example configured as described above, together with a comparative example, under the following conditions and procedures, and the results are shown in Table 1 below. In addition, in the numerical values in Table 1, the upper column represents the belt strength maintenance rate, and the lower column represents the belt elongation, for both the present example and the comparative example.

[Configuration of the toothed bell of this example) A] The flat braid 7 constituting the reinforcing body 2 is made of three strands of Kevlar (trade name, manufactured by DuPont) 1500 de (
Total denier number: 4500 de) was used. This flat braid 7 is first dipped in an isocyanate compound adhesive to form a subcoat layer, and then resorcinol.
A second coat layer was formed by dipping in formalin latex (RFL) adhesive, and then a top coat layer was formed by dipping in CR glue rubber, and then a stretching process was performed. These stretched plural flat braids 7, 7.
... were arranged in a spiral on the extension rubber layer 1 made of CR rubber so as not to create a twisted part, and the teeth 3 made of CR rubber were formed so as to bury each of the above-mentioned flat braids 7 thereon. After that, a nylon 5 is applied to the surface of the toothed portion 3 and molded and vulcanized to form the plurality of flat braids 7, 7.
... A toothed belt A was obtained in which the reinforcing body 2 constructed with the above was embedded in the belt main body 4. In addition, during the adhesive treatment, the adhesive is uniformly impregnated from the surface to the inside of the flat braided cord 7.

[Structure of toothed belt of comparative example] The reinforcing body was composed of four circular braided cords. Note that nothing was placed in the hollow part of the round braid. The rest is the same as in this embodiment.

[Procedure of bending fatigue test] As shown in Fig. 2, four large pulleys 8, 8°... and four small pulleys 9, 9... arranged between adjacent large pulleys 8, 8. Prepare a belt bending tester equipped with...
The toothed belt is attached to the large and small pulleys 8 and 9 of the belt bending tester.
The hook was passed and the toothed belt was run with a weight 10 and a predetermined tension applied. The diameter of each of the small pulleys 9 is 30 mm. Also, the toothed belt goes around and the above four small pulleys 9.9. . . . once each, that is, the number of times the belt is bent by each small pulley 9 four times is defined as one cycle.

Table 1 As is clear from the test data in Table 1, the belt strength retention rate of this example was significantly superior to that of the comparative example. In addition, in belt elongation, the present example had less change than the comparative example and had excellent dimensional stability.

Further, a non-deformability test against lateral pressure of the low edge V-belt A' was conducted under the following conditions and procedure along with a comparative example, and the results are shown in FIG.

[Reinforcing body 2 of the low edge V-belt 8 of this embodiment]
As the flat braid 7 constituting the braid, three strands of Kevlar (trade name, manufactured by DuPont) 1500 de (total denier: 4500 de) was used. This flat braided cord 7 is first dipped in an adhesive of isocyanate compound to form a sub-coat layer, then dipped in an adhesive of resorcinol formalin latex (RFL) to form a second coat layer, and then A top coat layer was formed by immersing the sample in a CR paste rubber, and then a stretching process was performed.

These stretched plural flat braids 7, 7. . . . are arranged in a spiral manner so that no twisted part occurs in the extension rubber layer 1 made of CR rubber, and cotton canvas 5-
．． 5- and molded and vulcanized, the plurality of flat braids 7, 7. ... A low edge V-belt A' in which the reinforcing body 2 constructed with the above is embedded in the belt body 4.
I got it. In the adhesive treatment described above, the adhesive is uniformly impregnated from the surface to the inside of the flat braided cord 7, as in the case of the toothed belt A.

[Construction of the low edge V-belt of the comparative example] The reinforcing body was constructed with four round braided cords. Note that nothing was placed in the hollow part of the round braid. The rest is the same as in this embodiment.

[Procedure for non-deformability test against lateral pressure] As shown in FIG. 4, a two-axis running test machine equipped with two pulleys 11 and 11 is prepared, and the low edge V-belt is attached to pulley 11. The tension applied to the low edge V-belt was changed in stages in step 2, and the belt was run for 5 minutes at 2000 r, p, m for each step. The amount of sinking of the V-belt was measured.

As a result, as shown in FIG. 5, in this example, even when the load of weight [2] increased from 60) cgr to 140 kgf, the amount of belt sinkage was relatively small at about 11;
In the comparative example, as the weight load increases, the amount of belt sinkage increases rapidly, and the load of weight 12 is 140 kg.
By the time it reached r, it had exceeded 2 stages and was more than twice that of this example. Therefore, it can be seen that the present example has much better non-deformability against belt side pressure than the comparative example.

In this way, in this embodiment, the reinforcing body 2 embedded in the belt main body 4 has a plurality of threads 6, 6, 6, 6, 6, Since it is composed of flat braids 7 strung with Since it has a flat shape without a hollow part like a braided cord, the amount of bending strain of the belt during bending is reduced compared to the case of a round braided cord, thereby making it possible to significantly improve the bending fatigue resistance. Furthermore, dimensional stability can also be ensured due to the structural characteristics of the flat braided cord 7.

Furthermore, in the above embodiment, since the flat braided cord 7 has a higher modulus of elasticity in the transverse direction than the round braided cord due to its structure, non-deformability against belt side pressure can be improved.

In addition, in the above embodiment, the flat braids 7 constituting the reinforcing body 2 are arranged in a spiral so that no twisted portion occurs, so that they do not twist even when external pressure is applied, and the above effect is reliably maintained. be able to.

In the above embodiment, the toothed belt A and the low-edge V belt A' are shown as rubber products, but the rubber products are not limited thereto, and may be used as power transmission belts or transportation belts such as other V belts, flat belts, and ribbed belts. may be, and furthermore,
Needless to say, the present invention can also be applied to rubber products other than belts, such as tires and hoses.

(Effects of the Invention) As explained above, according to the present invention as set forth in claim (1), since the reinforcing body is composed of a flat braid made of a plurality of threads, it is resistant to bending fatigue. It is possible to improve both the properties and the dimensional stability, and furthermore, it is possible to improve the non-deformability against lateral pressure.

Further, according to the present invention as set forth in claim (2), the flat braided cords constituting the reinforcing body are arranged in a spiral so that no twisted portion occurs, so that the above effect can be reliably maintained.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, and FIG. 1 is a longitudinal sectional front view of a toothed belt, and FIG. 2 is a schematic configuration diagram of a belt bending tester. Figure 3 is a perspective view of the low edge V-belt, Figure 4 is the 2
FIG. 5, which is a schematic diagram of the shaft running test machine, shows data showing the relationship between weight load and belt sinkage amount. Part 2...Reinforcement body 4...Belt body (product body) 6...Thread 7...Flat braided cord A...Toothed belt (fiber reinforced rubber product) A-...Row edge V belt ( Fiber-reinforced rubber products) 2...Reinforcement body 4 Belt body (product body) 6. Thread 7...Flat braided cord A...Toothed belt (fiber-reinforced rubber products) A'...Row edge V-belt (fiber Reinforced rubber products: Fig.) Fig. 1F Load v (kgf) Fig. 5 A' Fig. 4 Fig. 2

Claims (2)

[Claims] (1) A rubber product in which a reinforcing body made of fiber is embedded in the main body of the rubber product, and the reinforcing body is composed of a flat braid made of multiple threads. Characteristic fiber-reinforced rubber products. (2) The fiber-reinforced rubber product according to claim (1), wherein the flat braided cords constituting the reinforcing body are arranged in a spiral manner so that no twisted portion occurs.