JPH0243872Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in heat-recoverable articles.

Conventionally, heat-shrinkable articles have been used to protect the external surfaces of steel pipes for transporting oil, gas, etc., or to protect the external surfaces of welded joints of steel pipes. Additionally, thermally expandable articles are used for inner lining of steel pipes.

These conventional heat-shrinkable or heat-expandable articles are heated with a burner or the like before use, and are caused to shrink or expand to make them adhere tightly to the surface of the steel pipe. In some cases, the heat-shrinkable or heat-expandable articles did not come into close contact with each other at the sections and stepped sections, resulting in the formation of booth gaps.
When such a booth is formed, the surface of the steel pipe is exposed to the air, which tends to cause rust, but no effective means for preventing this has yet been found.

The present invention relates to a heat-recoverable article that solves the above-mentioned problems of the prior art, and is comprised of a heat-recoverable base material and a vaporizable rust preventive agent arranged in a layered manner.

Hereinafter, examples of the present invention will be explained with reference to the drawings. Figure 1 shows a tube-shaped heat-shrinkable article, in which 1 is a heat-shrinkable base material made of thermoplastics such as polyethylene, polypropylene, polyvinyl chloride, ethylene-vinyl acetate copolymer, natural rubber, silicone rubber, etc. , butyl rubber, ethylene-propylene copolymer rubber, etc., or a mixture thereof, with appropriate amounts of additives such as anti-aging agents, fillers, and colorants, as desired. A method in which the mixture is mixed and formed into a tube shape, then cross-linked as necessary, then heat-stretched in the radial direction to expand its diameter, and further maintained in this expanded state and cooled to impart heat-shrinkability. It is obtained by

2 is a volatile rust preventive agent arranged in a layered manner in the heat-shrinkable base material 1. To arrange a vaporizable rust preventive agent in a layered manner in a base material, apply the vaporizable rust preventive agent in a layered manner to the outer peripheral surface of the inner heat-shrinkable base material, and then apply another heat-shrinkable rust preventive agent on top of the rust preventive agent. It can be obtained by arranging a heat-shrinkable base material and integrating them, or by mixing a volatile rust preventive agent and a thermoplastic plastic on the outer circumferential surface of an inner heat-shrinkable base material and forming it into a tube shape, sheet shape, etc. A method may be employed in which a rust preventive-containing material is placed, another heat-shrinkable base material is further placed on the rust-preventive material, and then these are integrated.

Volatile rust inhibitors can be selected depending on the material of the adherend. For example, when the adherend is iron or iron alloy, organic amines such as cyclohexylamine, dicyclohexylamine, isopropylamine, etc. Salts of benzoic acid, nitrous acid, or various fatty acids are used, and when the adherend is copper or copper alloy, benzotriazole, benzotriazole derivatives, or salts of benzotriazole and organic amines are used.

Note that 3 is an adhesive layer provided on the inner surface of the heat-shrinkable base material 1 if desired, and a pressure-sensitive adhesive, a mastic agent, a hot melt adhesive, etc. can be used.

In order to use the heat-shrinkable article shown in FIG. 1, for example, to protect the outer surface of a welded joint of steel pipes, it is sufficient to place the article on the welded joint of steel pipes, heat it with a burner, etc., and cause the heat-shrinkable article to shrink. The heat-shrinkable article is bonded to the steel pipe weld, and volatilization of the volatile rust inhibitor begins. Therefore, even if a booth is formed between the heat-shrinkable article and the steel pipe, the volatile rust preventive agent remains in the booth, thereby preventing rust from forming on the steel pipe.

FIG. 2 shows a tube-shaped heat-expandable article, with 4
is a heat-expandable base material, which is made of the same components as the heat-shrinkable base material, and the components are mixed uniformly and formed into a tube shape, and then crosslinked as necessary, and then the diameter of the base material is increased under heating conditions. It can be obtained by a method in which thermal expandability is imparted by reducing the size of the material and then cooling it while maintaining this reduced state. An adhesive layer 3 is provided on the outer surface of the heat-expandable base material 4, and a vaporizable rust preventive agent is further disposed in the base material 4 in two layers.

This heat-expandable article can be used, for example, for lining the inner surface of a metal pipe, and even if a booth is formed between the heat-expandable article and the inner surface of the metal tube during lining work, the vaporizable rust preventive effect on the booth By retaining the agent, rusting of the metal pipe can be prevented.

FIG. 3 shows a sheet-like heat-shrinkable article, in which a vaporizable rust preventive agent 2 is arranged partially in a layered manner in a heat-shrinkable base material 1. These heat-shrinkable articles can be used, for example, to partially remove the anti-corrosion lining of a metal pipe to expose the metal surface, perform welding on this area, and then cover the welded area, and provide vapor protection. Since the rust agent 2 is arranged in a partially layered manner, the amount of rust preventive agent used can be saved. In addition, in the present invention, the volatile rust preventive agent can also be formed partially and in a layered manner only at the ends or only at the center of the base material.

The present invention is constructed as described above, and since a vaporizable rust preventive layer is formed in a heat-recoverable base material, it can be tightly adhered to a metal adherend by heat shrinking or thermal expansion on the adherend. Since the volatile rust preventive agent is gradually volatilized, it is possible to prevent rust from forming on the adherend.

[Brief explanation of drawings]

1 to 3 are sectional views showing examples of heat-recoverable articles according to the present invention. 1... Heat-shrinkable base material, 2... Volatile rust preventive agent, 3
...adhesive layer, 4...thermally expandable base material.

Claims (1)

[Scope of utility model registration request] A heat-recoverable article comprising a heat-recoverable base material and a vaporizable rust preventive agent arranged in a layered manner.