JPS597058B2 - General purpose belt - Google Patents

Description

[Detailed Description of the Invention] The present invention has a woven fabric layer as a core and elasticity.
The present invention relates to a belt whose basic material is a thermoplastic elastomer that softens when heated above a certain temperature, and in particular to a general-purpose belt suitable for transmitting light power and transporting medium-light objects.

Conventionally, general-purpose belts made of a laminate of thermoplastic resin such as polyvinyl chloride resin and canvas are generally known, but the canvas core of this type of belt is designed to avoid increasing the overall thickness of the belt. The two options were to use the minimum required number of laminated cores or to use a single-layer canvas core.

However, when used for conveying or transmitting medium-weight objects, permanent elongation occurs in the belt due to insufficient strength, which may eventually lead to problems such as belt breakage.

For this reason, it is conceivable to use a laminated core made of many layers of canvas as the belt core, but in this case, not only would the manufacturing process become complicated, but the belt would inevitably become thicker, making it unsuitable for small-diameter pulleys. Even if it could be used, the flexibility of the belt body would be impaired and it would break at the short diameter, which would cause problems.

On the other hand, a belt whose core is a rubber short fiber composite material in which reinforcing short fibers are kneaded into natural rubber or synthetic rubber and rolled into a sheet shape so that the reinforcing short fibers are oriented in the rolling direction. It is also generally known that in this type of belt, the short rubber fiber composite material is used as the core of the belt, and the thickness of the composite material serving as the core is 2 to 3% thick. This causes problems with the strength of the belt, and if it exceeds a few percent, the belt's longitudinal flexibility is inhibited, and since the matrix is rubber, it requires a vulcanization operation. .

The main purpose of the present invention is to eliminate the conventional belt as mentioned above.

The purpose is to improve the existing drawbacks, and to provide a belt that is strong, thin, and highly flexible. In the belt of the present invention, a hot melt adhesive layer made of a thermoplastic elastomer is provided between the upper and lower woven fabric core layers, and this thermoplastic elastomer layer contains reinforcing short fibers substantially oriented in the longitudinal direction of the belt. This general-purpose belt is characterized in that a thermoplastic elastomer layer is provided as a cover layer on both upper and lower surfaces or on one side of the laminate of the reinforcing short fiber-containing thermoplastic elastomer layer and the woven fabric core layer.

The present invention includes a belt in which a reinforcing short fiber-containing thermoplastic elastomer layer forming a hot melt adhesive layer is subjected to a stretching treatment. As mentioned above, the most important feature of the belt of the present invention lies in the thermoplastic elastomer layer containing short reinforcing fibers forming the hot melt adhesive layer.

That is, this layer utilizes its thermoplastic property to act as a hot melt adhesive between the two upper and lower woven fabric core layers, and also contains short fibers as reinforcing fibers to strengthen the woven fabric core. It also functions as an auxiliary core for the layer. The effect of this auxiliary core is that the auxiliary fibers are oriented or arranged in the longitudinal direction of the belt, that the reinforcing fiber-containing thermoplastic elastomer layer is subjected to stretching treatment, and that the elastomer material is made of high-strength thermoplastic elastomer. This can be further enhanced by using .

As a result, although the belt according to the present invention has a two-layer woven core belt, its strength is comparable to that of a three- to four-layer woven core belt, and its thickness is comparable to that of a conventional three- to four-layer woven core belt. The belt is innovative in that it is thinner than cloth core belts and has greater flexibility in both the longitudinal and width directions.

In the present invention, any polymer that can be processed as a thermoplastic material and has rubber-like elasticity can be used as the thermoplastic elastomer forming the pot-melt adhesive layer.

For example, thermoplastic polyester elastomer,
Thermoplastic polyurethane elastomer, thermoplastic styrene-butadiene elastomer, thermoplastic polyolefin elastomer, trans 1.4-polyisoprene, 1.2
-Although there are polybutadiene and the like, thermoplastic polyester elastomers have better properties required for belt materials such as abrasion resistance, bending fatigue resistance, oil resistance, chemical resistance, heat resistance and cold resistance, and preferably have a hardness of 70 to 98 ( JISK63O
1A).

Almost all fibers such as natural fibers, synthetic fibers, inorganic fibers, recycled fibers, and semi-synthetic fibers can be used as reinforcing fibers, but as described later, a heat fusion method is used as part of the manufacturing method of the belt of the present invention. Therefore, it is preferable that the fiber has a heat resistance higher than the softening strength of the thermoplastic elastomer used as the base material.

Examples include glass fiber, metal fiber, carbon fiber,
Examples include potassium titanate fiber and aromatic polyamide fiber.

When the type of reinforcing fiber is carbon fiber or special fiber whose surface is coated with metal, the hot melt adhesive layer can serve as an auxiliary core layer and an antistatic layer.

In the form of reinforcing short fibers, the fiber length is 0.1 to 1.
It is preferable that it is 5 or more.

If the fiber length is 15 or more, it becomes difficult to uniformly disperse the fibers in the matrix, and if the fiber length is less than 0.1', the reinforcing effect of the short fibers may be lost.

The amount of short fibers mixed is preferably 2 to 30 parts by weight per 100 parts by weight of the thermoplastic elastomer as a matrix.

When the amount of fibers mixed exceeds 30 parts by weight, workability decreases,
Moreover, the rubber-like elasticity of the matrix is lost, and if the amount is less than 2 parts by weight, hardly any reinforcing effect can be expected.

These reinforcing short fibers are manipulated so as to be oriented or arranged in the longitudinal direction of the belt for their effectiveness as an auxiliary core layer.

The reinforcing short fibers are subjected to adhesive treatment before being mixed in to ensure adhesion with the matrix.

Instead of bonding the fibers, a suitable adhesive may be added to the matrix in advance. In the belt of the present invention, various types of woven fabric can be used to form the core layer.

That is, the types of fibers constituting the woven fabric include natural fibers, synthetic fibers, inorganic fibers, recycled fibers, semi-synthetic fibers, etc.
As for the weave, plain weave, twill weave, and special weaves based on these can be used. In addition, monofilament and multifilament woven fabrics, silver thread-containing woven fabrics for electrical conductivity, etc. can also be used.

It is preferable that the woven fabric forming the core layer has a heat resistance higher than that of the softening thermoplastic elastomer used as the base material, and that it has been subjected to an adhesive treatment. As the thermoplastic elastomer forming the cover layer, any material that can be processed as a thermoplastic and has rubber-like elasticity can be used, and various materials can be used depending on the purpose of the belt.

For example, when the conveyed object is food, especially when the food comes into direct contact with the belt surface, it is preferable to use thermoplastic polyester elastomer as the material for the surface cover layer, and its hardness is 70 to 98 ( J[SK63Ol
A) is appropriate.

Moreover, it is of course possible to use different thermoplastic materials or materials with different grades of performance as the front cover layer and the back cover layer. Next, a method for manufacturing a belt according to the present invention will be explained.

First, a reinforcing short fiber-containing thermoplastic elastomer layer that will become a hot melt adhesive layer is formed.

A mixture of short fibers and thermoplastic elastomer is formed into a film or sheet using an extruder or the like, and in this step, the short fibers are oriented substantially in the longitudinal direction. A woven fabric layer as a core layer is overlaid on both the upper and lower surfaces of the film or sheet-like hot melt adhesive layer made in this way.
Furthermore, by laminating a thermoplastic elastomer layer as a cover layer on both sides or one side, and heating this laminate, only the thermoplastic elastomer forming the hot melt adhesive layer and the thermoplastic elastomer forming the cover layer are softened or The laminate is integrated into a belt by partially melting and then cooling.

Pressure may be applied as necessary during heating, softening and melting, and in order to prevent the cover layer from flowing or losing its shape, a release paper, etc. may be placed on the outside of the cover layer, and heating, softening and melting and pressing may be performed. Good too. When stretching the reinforcing short fiber-containing thermoplastic elastomer layer that forms the hot melt adhesive layer, a mixture of the short fibers and thermoplastic elastomer should be formed into a film or sheet using an extruder, etc., and then stretched. Bye.

A woven fabric serving as a core layer is layered on both the upper and lower surfaces of the hot melt adhesive layer thus formed, and a thermoplastic elastomer layer serving as a cover layer is layered on both or one side of the woven fabric, and the laminate is rolled under tension. By heating to an appropriate temperature, the stretched reinforcing short fiber-containing thermoplastic elastomer is heat-set, and a surface portion of the reinforcing fiber-containing thermoplastic elastomer layer and a cover layer are formed. Only the thermoplastic elastomer layer is softened or partially melted, and then cooled to integrate the laminate to form a belt.

Pressure may be applied as necessary during this heating, softening and melting process.In order to prevent the cover layer from flowing or losing its shape, release paper or the like is placed on the outside of the cover layer, and the heating, softening and pressing operations are performed. It's okay to get old.

Examples will be described below. Example 1 Pelprene 8P150M manufactured by Toyobo Co., Ltd. was used as the thermoplastic elastomer forming the hot melt adhesive layer, and aromatic polyamide fiber (poly-P-phenylene terephthalamide fiber) with a fiber length of about 5% that was adhesively treated was used as the reinforcing fiber. ,
Using Kevlar 8) manufactured by Du, POnt Co., Ltd., the blended amount of fibers was 15 parts by weight based on the matritas, and these were extruded using an extruder to form a sheet with a thickness of about 1 to 100 ml. Polyethylene terephthalate fiber woven fabric and a thermoplastic elastomer sheet with a thickness of about 1% (Toyobo Pelprene 8P40H) forming the cover layer
) were superimposed, release paper was placed on both sides of the laminate, and the laminate was integrated by heating (160 to 170° C.) and pressing with a pair of rollers to obtain a belt with a thickness of about 2.5%.

This belt had a tensile strength of 245 kg/Cml and a 3% modulus of 52 kg/CTfl.

Separately, when we made a belt of almost the same size from the same material without using the reinforcing fiber Kevlar and examined its strength, we found that the tensile strength was 1101<9/? , 3% modulus 21k
g/CI! It was l.

Example 2 The raw materials used, their shapes and blending ratios are the same as in Example 1.

Pelprene 8P150 forming hot melt adhesive layer
M and Kevlar 8 as reinforcing fibers are extruded into a sheet using an extruder, and then stretched approximately three times at a temperature of 130°C to form a sheet approximately 1' thick. Polyethylene as a core layer is coated on both sides of the sheet. A terephthalate fiber woven fabric and a sheet of Pelprene 8P40H having a thickness of about 1 to 100 ml as a cover layer are superimposed and led to a heat-setting step.

In this process, the temperature of most of the stretched sheet material is set at 150°C from the entrance to perform heat-setting treatment, and near the exit of the process, it is heated to 160 to 170°C and pressurized with a roller pair. The laminate is integrated with a thickness of about 2
．． 5~ belts were obtained.

The tensile strength of this belt is 310k9/C7ll3% modulus 701<9/? It was hot. Separately, the same treatment was carried out using the same material without using the reinforcing fiber KevIar, and belts of approximately the same size were created.

The tensile strength of this belt was 205 kg/C7!13% modulus 45 kg/Cfn.

[Brief explanation of the drawing]

FIG. 1 shows a belt according to the present invention, in which short fibers are used as reinforcing fibers. FIG. 2 is a sectional view taken along the line A-X in FIG. 1. 1,5・
...Front and back cover layers, 2, 4... Woven fabric core layer, 3... Hot melt adhesive layer, 6...
・Reinforcement fiber.

Claims (1)

[Claims] 1. In a belt having a woven fabric laminated core, a hot melt adhesive layer made of a thermoplastic elastomer is provided between the upper and lower woven fabric core layers, and this thermoplastic elastomer layer substantially covers the belt. Containing reinforcing short fibers oriented in the longitudinal direction, a thermoplastic elastomer layer as a cover layer is provided on both the upper and lower surfaces or on one side of the laminate of the reinforcing short fiber-containing thermoplastic elastomer layer and the woven fabric core. A general-purpose belt that is characterized by the ability to 2. The general-purpose belt according to claim 1, wherein the reinforcing short fiber-containing thermoplastic elastomer layer forming the hot melt adhesive layer has been subjected to a stretching treatment. 3. Claims 1 and 2, characterized in that the thermoplastic elastomer containing reinforcing short fibers forming the hot melt adhesive layer and the thermoplastic elastomer forming the cover layer are thermoplastic polyester elastomers. General purpose belt as described.