JPH10310648A - Fiber-reinforced rubber article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fiber-reinforced rubber article that has an improved flex fatigue resistance and can be a thin-gauge lightweight article, by embedding fibrous reinforcement composed of flat braids having a specified braiding angle in the body of a rubber article. SOLUTION: This article contains a fibrous reinforcement composed of flat braids and embedded in the body of the article. The flat braid used is one prepd. by braiding at least three strands into a flat form with a braider at a braiding angle α (of three strands 1-a, 1-b, and 1-c) of 10-40 deg.. Generally, org. fibers of 200-5,000 denier are used as the materials of the strands used for peparing flat braids. The use of the flat braids as the reinforcement can give a reinforced article which has an esp. improved flex fatigue resistance in comparison with an article reinforced with double-twist-yarn cords conventionally used and which can be thin-gauged and lightweight more than an article reinforced with double-twistyarn cords or circular braids.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fiber reinforced rubber product, and more particularly to a rubber product having a fiber main body buried in a product body and having improved bending fatigue resistance and capable of being thinned. .

[0002]

2. Description of the Related Art Conventionally, tires, conveyor belts,
Rubber industrial products such as hoses and air springs are required to have properties such as high strength, high elastic modulus, high dimensional stability, and high adhesiveness. Therefore, a reinforcing body is usually embedded in the rubber product body. ing. As the reinforcing member, an organic fiber cord generally having characteristics such as high strength, high elastic modulus, high bending fatigue resistance, and heat resistance is used. Conventionally, as the reinforcing member, a twisted cord obtained by twisting a plurality of yarns is used, and the twisted yarn can be classified into a type such as a twin twisted yarn and a single twisted yarn depending on the twisting method. As the above-mentioned twisted cord material, usually twin twisted yarn is most often used. By the way, in the case of tires and the like, recently, it has been attempted to reduce the amount of fibers used to reduce the thickness of a thin gauge by using a reinforcing member having particularly high strength and a high elastic modulus. There is a need for a reinforcement having excellent bending fatigue properties.

[0003] However, when a twin-twisted cord generally used in the past is used as a reinforcing member, the filaments in the interior of the yarn are intensely contacted with each other on the upper-twisted intersecting surface and are worn. It is inevitable that abrasion, breakage or reduction in strength occurs, and the bending fatigue resistance deteriorates. It has been proposed to use a round braid as a rubber reinforcement having improved flex fatigue resistance (Japanese Patent Publication No. 6-9 / 1994).
In the case of this round-twisted yarn, since the center becomes a hollow cylindrical shape (see FIG. 4), there is a problem that the whole becomes thick, which does not meet the purpose of the present application and is difficult to put to practical use.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a fiber reinforced rubber product having improved bending fatigue resistance and capable of reducing the weight of a thin gauge under such circumstances. is there.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to develop a fiber reinforced rubber product having the above-mentioned preferable properties, and as a result, it has been found that a fiber formed from a flat braid having a specific braiding angle is obtained. It has been found that the object can be achieved by embedding a reinforcing member made of a rubber product body. The present invention has been completed based on such findings.

That is, the present invention relates to a rubber product in which a reinforcing body made of fiber is embedded in a rubber product main body,
3 so that the reinforcing body has an assembling angle of 10 to 40 degrees.
It is intended to provide a fiber reinforced rubber product characterized by being constituted by a flat braided braid composed of at least one thread.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The fiber reinforced rubber product of the present invention is a product in which a fiber reinforced body composed of a flat braid is embedded in a rubber product body. The braid is a kind of cloth in which yarns are slanted and intersected with the cloth because of the movement of rotating several to several tens of bobbins in a figure eight shape on a horizontal plane and the movement of winding the made cloth in the vertical direction. It is. In the present invention, as the braid, a flat braid that is woven by a braiding machine in a plane using three or more yarns is used. In the case of three flat braids, a so-called "braid" is used.

FIG. 1 is an enlarged view showing an example of the flat-braided braid used in the present invention, and shows three yarns 1-a, 1-b and 1-c. Shows a structure assembled so that the assembly angle becomes α degrees.
FIG. 2 is a cross-sectional view of the flat strung braid in FIG.
In the present invention, the braiding angle (α degree in FIG. 1) is 10 to 4 by three or more yarns as the flat braid.
Those assembled so as to be in the range of 0 degrees are used. If the assembling angle is less than 10 degrees, the assembling angle is too shallow, so that the convergence between the filaments is reduced and the bending fatigue resistance is deteriorated. On the other hand, when it exceeds 40 degrees, the assembling angle is too deep, so that the contact wear between filaments is apt to occur, and the bending fatigue resistance is reduced, and the elongation is too high, and the dimensional stability is also reduced.

As described above, by setting the braiding angle in the range of 10 to 40 degrees, the flat braid used in the present invention has a shallower angle at which the filaments come into contact with each other than the conventional twin-twisted cord, and has a contact abrasion. Can be suppressed, and the bending fatigue resistance is improved. The material of the thread used in the flat braid is not particularly limited, and is appropriately selected from inorganic fibers, organic fibers, metal fibers, and the like, which are conventionally used in a reinforcing body of a rubber product, depending on the application. Of these, organic fibers are commonly used. As the organic fibers, for example, polyester fibers, nylon fibers, rayon fibers, and aramid fibers are mainly used. The thickness of the yarn to be used is not particularly limited, but when the yarn is made of an organic fiber, the thickness is usually 200 to 200.
Those having a range of 5000 denier are used.

The number of yarns constituting the flat braid used in the present invention may be three or more, and is not particularly limited and may be appropriately selected depending on the application. The three minimum units are also advantageous in that they are easy to handle. In the fiber-reinforced rubber product of the present invention, a reinforcing body composed of a plurality of flat braids is embedded in a rubber product body, but before the embedding,
The flat braid is usually subjected to an adhesive treatment or a stretching heat treatment. Here, the method of treating the adhesive is not particularly limited, and may be appropriately selected from various methods conventionally applied to a reinforcing body of a rubber product according to the application. For example, a method in which resorcin-formalin resin latex (RFL) is used as an adhesive,
Alternatively, a method of treating by using a combination of an epoxy resin, an isocyanate compound, an ethylene urea compound, and an adhesive such as RFL can be adopted. In this adhesive treatment, a dipping method is desirable in order to uniformly impregnate the adhesive from the surface to the inside of the braid.

Such an adhesive treatment is carried out, if necessary, by a conventionally used method in combination with a stretching treatment (tensing treatment). There is no particular limitation on the method of manufacturing the fiber reinforced rubber product by embedding the reinforcing body composed of the flat braid in the rubber product main body, from the methods conventionally used in the manufacture of fiber reinforced rubber products. It can be appropriately selected and used depending on the use. For example, when the fiber-reinforced rubber product is a tire, as a reinforcing material for a carcass, a flat cloth braided warp woven fabric of the present invention can be used instead of a normal flat cloth.

The fiber-reinforced rubber product of the present invention obtained as described above has a particularly excellent bending fatigue resistance as compared with a product using a conventional twin-twisted yarn cord as a reinforcing body, and further has a twin-twisted yarn cord or a rounded It is possible to reduce the weight of the thin gauge as compared with the one using the braid. There are various fiber-reinforced rubber products of the present invention, and typical examples thereof include the above-mentioned tires, conveyor belts, hoses, and air springs.

[0013]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 As a yarn, three bundles of high-density polyester filaments of 1500 denier were assembled in a plane at an angle of 10 degrees to produce a flat braid shown in FIGS. 1 and 2. Next, the flat braid was immersed in an adhesive (dip liquid) composed of resorcinol-formalin resin latex, dipped, and then wound up after drying and tensioning.
With respect to the cord made of the flat braid treated with the adhesive, the strength retention after bending fatigue and the elongation at break were measured by the following methods. Table 2 shows the results. Table 2 also shows the thickness and width of the cord before the adhesive treatment.

(1) Tensile strength retention after bending fatigue Thirty adhesive-treated cords are arranged in a width of 5 cm,
A sheet of unvulcanized compounded rubber having the composition shown in the table and having a thickness of 0.4 mm was adhered from both sides to produce a rubber topping sheet having a width of 5 cm and a length of 60 cm. Then, an unvulcanized compounded rubber sheet having a composition shown in Table 1 having a thickness of 3 mm is sandwiched between the two topping sheets obtained in this manner. An unvulcanized compounded rubber sheet having the composition shown in Table 1 is adhered so that both ends of the cord are fixed, and heat treatment is performed at 145 ° C. for 40 minutes under a constant length under a pressure of 20 kg / cm ² to perform vulcanization. Then, a sample for bending fatigue resistance test was prepared. next,
This sample was placed on a pulley having a diameter of 60 mm, and a load of 150 kg was applied from both ends to bend 5000 times per hour under an atmosphere temperature of 100 ° C. After bending 500,000 times, the sample was removed, and the cord on the side in contact with the pulley (the side subjected to repeated compressive strain) was taken out of the two polyester fiber cord layers, and the breaking strength was measured. The retention rate (%) with respect to the breaking strength of the cord was calculated, and the bending fatigue resistance of the cord was evaluated.

(2) Elongation at break The adhesive-treated cord was embedded in the unvulcanized compounded rubber composition shown in Table 1, and both ends of the cord were fixed.
Vulcanization treatment was performed for 0 minutes in a constant length state. Then, after allowing to cool naturally in the fixed length state, take out the vulcanized sample, cut out the cord with scissors while the rubber is around, and remove the rubber on the surface to avoid fluffing when peeling the cord. I scraped as much as I could. In accordance with JIS L1017, the cord was subjected to a tensile test with an autograph manufactured by Shimadzu Corporation while the rubber was still attached to the surface, and the elongation at break (%) was measured. The elongation was indicated by an index when the test was performed.

Examples 2 to 4 and Comparative Examples 1 and 2 Flat braided braids were prepared and bonded in the same manner as in Example 1 except that the assembling angle was changed as shown in Table 1. After the agent treatment, the cord was measured for the strength retention after bending fatigue and the elongation at break. The results, together with the thickness and width of the cord before adhesive treatment, are
It is shown in the table.

Comparative Example 3 As a yarn, a high-density polyester filament bundle of 1500 denier was used.
The twin-twisted cord having the cross-sectional shape shown in FIG. After that, the cord was treated with an adhesive in the same manner as in Example 1, and then the cord was measured for the strength retention after bending fatigue and the elongation at break. The results are shown in Table 2 together with the thickness and width of the cord before bonding.

Comparative Example 4 As a yarn, four bundles of high-density 1500 filament polyester filaments were assembled at an assembly angle of 30 degrees.
The round braid having the cross-sectional shape shown in FIG. After that, the cord was treated with an adhesive in the same manner as in Example 1, and then the cord was measured for the strength retention after bending fatigue and the elongation at break. The results are shown in Table 2 together with the thickness and width of the cord before the adhesive treatment.

[0019]

[Table 1]

[0020]

[Table 2]

[0021]

[Table 3]

As can be seen from Table 2, Comparative Examples 1 and 2 are flat braided braids as in the example, but since the braiding angle is out of the range of 10 to 40 degrees, the bending fatigue The subsequent strength retention is considerably lower than in the examples. Also, the twin-twisted cord of Comparative Example 3 has a considerably lower strength retention after bending fatigue than the Example. On the other hand, although the round braid of Comparative Example 4 has a high strength retention after bending fatigue, the cord is thick and it is difficult to form a Pu gauge.

[0023]

The fiber reinforced rubber product of the present invention uses a flat braid having a specific braiding angle as a reinforcing body, and therefore, has a higher quality than a conventional twin stranded cord.
In particular, since the bending braid resistance is improved and the cross section of the flat braid is flattened, the weight of the thin gauge can be reduced as compared with a twin-twisted cord or a round braid. Also,
When a twin-twisted yarn cord is used as a reinforcing body, this requires two twisting steps of a top twist and a bottom twist,
In the case of a flat braid, the cord can be produced in one step, so that the twisting process can be simplified.

[Brief description of the drawings]

FIG. 1 is an enlarged view showing an example of a flat braid used in the present invention.

FIG. 2 is a sectional view of the flat braid in FIG. 1;

FIG. 3 is a cross-sectional view of an example of a twin-twisted yarn cord.

FIG. 4 is a cross-sectional view of an example of a round braid.

[Explanation of symbols]

 1-a: Yarn 1-b: Yarn 1-c: Yarn

Claims (1)

[Claims] 1. A rubber product in which a reinforcing member made of fiber is embedded in a rubber product main body, wherein the reinforcing member is formed by three or more yarns so that a setting angle is 10 to 40 degrees. A fiber-reinforced rubber product comprising a flat braid.