JPH0374202A - Static electricity neutralizing tire - Google Patents

Abstract

PURPOSE:To restrict generation of static electricity in a solid tire made of polyurethane, synthetic rubber, and natural rubber by mixing a prescribed amount of carbon fibers having a prescribed fiber length in such a manner that the fibers contact with each other and that tips of a part of the fibers face the outer peripheral surface of the tire. CONSTITUTION:0.005 to 10weight% of acrylic carbon fibers each having a length of 1 to 10mm are mixed into base rubber. These carbon fibers 2 are mixed in such a manner that they are brought in contact with each other and that tips of a part of carbon fibers face the outer peripheral surface of a tire. With this contrivance, since electricity is conducted via a carbon fiber, static electricity is discharged into the air from the tire surface. Accordingly, generation of static electricity can be prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a static electricity neutralizing tire, which is used, for example, as a tire for automatic guided vehicles at work sites where static electricity generation causes electromagnetic interference and tends to cause malfunctions. It is something that

[Conventional technology]

In recent years, automatic guided vehicles have come into widespread use in factories to improve work efficiency.

This automatic guided vehicle performs predetermined operations based on electrical commands from a command center built into the vehicle or from a remote location, but static electricity is generated due to friction between the tires and the floor surface.

Tires for automatic guided vehicles are usually solid tires, but in factories that carry out precision processing, for example, it is necessary to prevent dust and germs from getting in, so tires that do not contain carbon are used to avoid contaminating the floor surface. It is often made of polyurethane or the like.

However, non-carbon tires generate a particularly large amount of static electricity, which can cause electromagnetic interference in electrical systems, often causing malfunctions.

[Problem to be solved by the invention]

Some methods of removing static electricity generated from the tires of automatic guided vehicles include grounding or installing static electricity removal brushes, but these methods are based on the idea of removing the generated static electricity afterward. The drawback is that electromagnetic interference may occur if removal is not complete.

The method of grounding is difficult because the transport vehicle itself moves = 1-2, and the effectiveness of the static elimination brush varies depending on the performance of the brush and the position of the installation.
It was still not satisfactory.

Therefore, an object of the present invention is to provide a tire that suppresses the generation of static electricity itself, that is, a static electricity neutralizing tire.

[Means to solve the problem]

Means for solving the problems of the present invention are as follows.

That is, the static electricity neutralizing tire according to the present invention is made of polyurethane,
In a tire made of base rubber or natural rubber, carbon fibers with a fiber length of 1 to 1.0+nn+ are mixed in a range of 0.005 to ]-0% by weight, and the carbon fibers are in contact with each other, and the tips are It is characterized by being blended so that the outer circumferential surface of the tire faces the outer circumferential surface of the tire.

The present invention will be explained in more detail below.

The base rubber of the tire used in the present invention is polyurethane, sole rubber or natural rubber, and the type of polyurethane is not particularly limited, but thermosetting ones with high load resistance are preferred. The bottom rubber may be diene-based, olefin-based, silicone-based, or other elastomer. Natural rubber can also be used, but since adding carbon will stain the floor surface, rubber is used by mixing fillers and reinforcing agents such as silicon oxide (white carbon).

The carbon fiber mixed into the base rubber is commercially available acrylic,
Pitch-based materials can be used, but the average fiber length is 1 to 1.
It must be 01m+. This fiber length is the length when the fiber is mixed into a tire. These fibers must be mixed into the tire in such a way that they are in contact with each other.

If the average length of the fibers is shorter than 1 mm, contact between the carbon fibers becomes difficult, and the antistatic effect (static neutralization effect) decreases.
Moreover, if it exceeds 10 mm, excessive entanglement of fibers will occur, which is not preferable. The preferred range is 3 to 6 m. Further, the fineness of the fibers is preferably 1 to 5 deniers and is uncrimped and straight.

On the other hand, it is necessary that some of the carbon fibers be blended in the outer circumferential direction 4 of the tire, and that some of the fibers should have their tips facing the outer circumferential surface of the tire. In other words, each fiber must be properly intertwined and in contact with each other, and if they are mixed completely randomly or if each fiber is bent, the antistatic effect (static neutralization effect) will be reduced. I can't get it.

There are no particular limitations on the method of blending carbon fibers in the circumferential direction of the tire, with a portion of the tips facing the outer circumferential surface of the tire, but if the fibers are mixed in with a large shear, the fibers may break and become short. Therefore, it is preferable that the viscosity of the rubber or resin before molding is low to some extent and has fluidity.

By mixing carbon fibers and injecting them into a mold without causing too much crosstalk, the carbon fibers can be brought into contact with each other as described above, and a portion of their tips can be exposed to the outer peripheral surface of the tire.

Further, although carbon fibers can be mixed alone, it is preferable to mix carbon fibers with other synthetic fibers to form a static electricity neutralizing material into the shape of sheet 1, for example, because it is easy to handle.

The amount of carbon fiber mixed is 0.00 based on the total composition of the tire.
The amount is 5 to 10% by weight, but according to the inventor's experiments, the optimum range tends to vary depending on the pace polymer used. For example, in the case of polyurethane, it is 0.005 to 5% by weight.
is preferable, and in the case of rubber, 3 to 10% by weight is preferable.

This is thought to be originally due to the difference in electrical resistance of the resin and rubber, as well as the way the carbon fibers are bent when mixed and the degree of blending.

In addition, ordinary fillers, reinforcing agents, etc. may be mixed into the tire of the present invention.

[For production]

It is well known that carbon fibers are conductive, but in the present invention, the mixed carbon fibers have a certain length, most of them are in contact with each other, and a part of their tips are Since it is formulated so that it faces the outer circumferential surface of the tire, the generated static electricity is not transferred to the base rubber and is directly discharged from the surface into the atmosphere, so it is possible to maintain a state in which so-called static electricity does not occur. it is conceivable that.

〔Example〕

Tires with and without carbon fibers were formed using polyurethane and natural rubber and their electrical performance was measured, with the results shown in the following table.

Shown in the table. It can be observed that the carbon fibers 2 are in contact with each other in the tire made of polyurethane and are blended so that a part of their tips face the outer peripheral surface of the tire.

[Brief explanation of drawings]

The first drawing is a partially cutaway front view of a solid tire according to the present invention. Engineering: solid tire, 2: carbon fiber.

Claims (1)

[Claims] (1) In a solid tire made of polyurethane, synthetic rubber, or natural rubber, carbon fibers with a fiber length of 1 to 10 mm are mixed in a range of 0.005 to 10% by weight, and the carbon fibers are in contact with each other and at the tip. A static electricity neutralizing tire characterized in that a part of the compound is blended so as to face the outer circumferential surface of the tire.