JPH06218873A - Thermal recovery shield tube - Google Patents

Abstract

PURPOSE:To obtain a thermal recovery shield tube having high shield properties and high slide bending resistance by providing layers composed of a thermoplastic resin to the inner surface of a layer composed of rubber or resin having thermal recovery properties and providing a metal layer between thermoplastic layers. CONSTITUTION:Thermoplastic resin layers 2 and a shield layer 3 composed of a metal, for example, aluminum are provided to the inner surface of a layer composed of rubber or resin having thermal recovery properties, that is, a thermal recovery tube 1. The layer 1 composed of the rubber or resin having thermal recovery properties is mainly formed from a thermal recovery resin crosslinked if necessary by the irradiation with electron beam and subjected to heat expanding processing. A conductive filler may be added to a thermal resin layer 2. By this method, the thermal recovery tube is closely bonded to the metal layer and has good appearance before and after shrinkage.

Description

Detailed Description of the Invention

[0001]

[Industrial application] The present invention relates to a heat-recoverable shield tube which exhibits an excellent effect in shielding electromagnetic waves such as electric wires and cables.

[0002]

2. Description of the Related Art In recent years, light and thin electric and electronic devices
With the shortening of the size and the increasing frequency, an electromagnetic wave shielding layer in a small space, that is, an electromagnetic wave shielding tube is required. An electric wire or a shield heat recovery article that already has a thermoplastic resin having heat recovery as an outer layer and an electromagnetic wave shield layer containing a conductive filler on the inner peripheral surface (Japanese Patent Laid-Open No. Sho 6-62).
No. 3-245998), and the outer layer is the same,
A structure having a metal layer on the inner surface has also been proposed.

However, the electromagnetic wave shield layer containing only the conductive filler is not sufficiently effective and is hardly used. Further, in the structure having the metal layer, the metal layer needs to be sufficiently thin to have heat recovery. However, even if it is sufficiently thin, the metal itself does not shrink, so that at the end of shrinkage, the resin layer having heat recoverability and the metal layer portion do not adhere to each other. For this reason, there is a problem that the metal layer portion is broken during sliding, and it is not used much in practice.

[0004]

Means for Solving the Problems As a result of extensive studies on such problems, the present inventor has found that a layer made of a thermoplastic resin is provided on the inner surface of a layer made of rubber or resin having heat recoverability, and The present invention has been completed by finding that it is possible to provide a heat-recoverable shield tube in which the above problems are solved by providing a structure having a metal layer between the thermoplastic resin layers, and completed the present invention.

That is, the present invention is: a heat-recoverable rubber having a layer made of a thermoplastic resin on the inner surface of a layer made of a rubber or a resin having a heat-recoverable property, and having a metal layer between the thermoplastic resin layers. Provide a shield tube. It is also characterized in that the layer made of a thermoplastic resin contains a conductive filler. Further, there is also provided a heat-recoverable shield tube having a cross-linked resin or rubber layer on the inner surface of the thermoplastic resin layer, and either or both of the resin or rubber forming the innermost layer and the outermost layer has heat recoverability. To do.

The present invention will be described below in detail with reference to the drawings. FIG. 1 shows a layer made of rubber or resin having a heat recovery property, that is, a thermoplastic resin layer 2 and a shield layer 3 made of a metal such as an aluminum layer on the inner surface of a heat recovery tube 1.
FIG. 3 is a schematic diagram showing before and after contraction of the heat-recoverable shield tube made of.

In the present invention, the layer 1 made of rubber or resin having heat recoverability means that the resin having heat recoverability is mainly crosslinked by electron beam irradiation or the like, if necessary, and processed by heat expansion or the like. It means that it has a heat recovery property.

[0008] Moreover, the layer made of rubber having heat recovery property means that rubber, that is, elastomer does not originally have a melting point and does not show heat recovery property, but a laminated metal layer is spread by heating. Then, it is extended following it, which means that it encloses the metal layer and exhibits pseudo heat recovery.

Examples of the heat-recoverable resin include crosslinkable polyethylene, ethylene-vinyl acetate copolymer, ethylene-methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-methacrylic acid copolymer. Examples thereof include coalesce and fluororesin such as polyvinylidene fluoride.

As the rubber having the heat recovery property, for example, ethylene-propylene rubber, ethylene-propylene-diene rubber, butyl rubber, styrene-butadiene copolymer rubber, trans polyisoprene, acrylic rubber, fluororubber, polyurethane and the like are molded. Examples include rubber and polynorbornene used in products.

In the case of the present invention, in order to further enhance the shielding effect, the layer 2 made of a thermoplastic resin may contain a conductive filler. Examples of the conductive filler include metal powders such as nickel, copper and silver, alloy powders such as solder, metal whiskers, glass fibers plated with metal, and carbon.

The blending ratio of the conductive filler to the thermoplastic resin layer 2'is not particularly limited as long as the electromagnetic wave shield formed by these works effectively. In particular,
The amount is 20 to 300 parts by weight, preferably 100 to 200 parts by weight, based on 100 parts by weight of the thermoplastic resin, although it is determined in consideration of the type, shape, size, specific gravity and the like of the conductive filler.

The above thermoplastic resin is not particularly limited,
A layer that is easily bonded to the rubber or resin layer 1 having heat recovery and the metal layer 3, particularly a hot-melt adhesive layer is preferable, and examples thereof include polyethylene, ethylene-based copolymer, polypropylene, polyamide, polystyrene, and ABS resin. it can.

In the present invention, by providing the metal shield layer 3 between the thermoplastic resin layers 2, the heat recovery tube 1 and the metal layer 3 are in close contact with each other even after the contraction is completed,
When the metal layer 3 is in close contact with the thermoplastic resin layer 2, the metal layer 3 such as a metal foil bends with a relatively large radius of curvature during sliding, which makes it difficult for the metal foil to break, and causes the metal layer to shrink when contracted. Since the wrinkles are also dispersed in the thermoplastic resin, it is possible to obtain a heat-recoverable shield tube which has a good appearance both before and after shrinkage and which has excellent flexibility and a high shielding effect.

Also, when mounting the earth, it is possible to surely contact the metal layer 3 during the contraction work only by roughly setting it on the thermoplastic resin layer 2. Further, as shown in FIG. 4, by providing a crosslinked rubber or resin layer 4 such as a crosslinked tube on the inner surface of the thermoplastic resin layer 2,
The metal layer 3 is prevented from protruding from the thermoplastic resin layer 2 during shrinking work.

That is, even in the shrinking temperature range, since the innermost layer is crosslinked, the crosslinked resin or rubber layer (crosslinked tube layer) 4 is less deformed even when an external force is applied during heating. Therefore, in the structure of the heat-recoverable shield tube of the present invention, the metal layer 3 such as the metal foil does not penetrate the cross-linked tube layer 4 at the time of heat shrinkage, and always stays in the thermoplastic resin layer 2, so that the sliding is further improved. Bending resistance is improved.

The rubber or resin constituting the crosslinked resin or the rubber layer 4 is not particularly limited, but the same rubber or resin having heat recoverability as that used for the resin layer 1 can be used. In order to cross-link the resin or rubber, electron beam cross-linking can be carried out, or a cross-linking agent such as dicumylperoxide can be preliminarily blended to carry out heating partial cross-linking.

Further, as shown in FIG. 5, both or one of the outermost layer and the innermost layer may be composed of a rubber or resin layer 1 having a heat recovery property. A conductive filler may be added to the innermost crosslinked resin layer 4 in order to further enhance the shielding effect.

The heat-recoverable rubber or resin layer 1, thermoplastic resin layer 2, cross-linked rubber or resin layer 4 of the innermost and outermost layers of the present invention may be mixed with conventional flame retardants, flame retardant aids, and fillers. , Antioxidants, light stabilizers, lubricants, carbon black, pigments and the like can be blended according to the purpose of use.

The production method of the heat-recoverable shield tube of the present invention is not particularly limited, but in general, (a) a rubber or resin layer 1 having a heat-recovery property and a thermoplastic resin layer 2 are coextruded. It is molded into a tube and electron-beam cross-linked if necessary, or a cross-linking agent such as dicumyl peroxide is preliminarily blended and partially cross-linked by heating to produce a heat-recoverable tube. (B) The metal layer 3 having the thermoplastic resin layer 2 on its inner surface is wound into a tube by tape winding or molding.
(C) Insert the tube (b) into the heat-recoverable tube (b), crosslink the electron beam as necessary, heat and expand the diameter, and then cool. (D) If necessary, it is preferable to dispose the mold metal tube in the tube (b), heat-shrink it, and pull out the metal tube.

[0021]

The present invention is illustrated by the following examples, which do not limit the scope of the invention. It will be described with reference to FIG. As the resin 1 having heat recoverability, crosslinkable polyethylene was used. Aluminum was used for the shield metal layer 3> Polyamide hot melt adhesive was used for the thermoplastic resin layer 2. A polyamide hot melt adhesive was extruded into a tube having an inner diameter of 10 mm and a wall thickness of 0.5 mm, and a 0.1 mm aluminum tape was wrapped around the surface by half wrap. Further, polyethylene 1 and a polyamide hot melt adhesive containing methylhydroquinone as a crosslinking inhibitor are coextruded into a tube shape, irradiated with 24 Mrad of an electron beam, heated to 150 ° C., and doubled in diameter and cooled. Inner diameter 12 mm, wall thickness (polyethylene layer;
A heat shrinkable tube having a thickness of 0.5 mm and a polyamide layer of 0.2 mm was prepared.

A metal tube of 9.5 mm was placed on the inner surface of the aluminum tape-wrapped tube, and a heat-shrinkable tube was placed on the outer surface of the aluminum tape-wound tube. After heat-shrinking, the metal tube was pulled out, and as shown in FIG. A heat-recoverable shield tube having the shape shown in was prepared. When the heat-recoverable shield tube shown in FIG. 1 was heated and shrunk, it shrank as shown in the right part of FIG.

In FIG. 2, a polyamide hot melt adhesive 2 mixed with carbon was used. In FIG. 3, a resin layer 1 (cross-linked polyethylene) having further heat recoverability is arranged on the inner layer of the heat recoverable shield tube shown in FIG. In FIG. 4, a crosslinked tube 4 is further arranged in the inner layer of the heat recovery shield tube of FIG. In FIG. 5, the heat-recoverable shield tube of FIG. 2 has a heat-recoverable resin layer 1 as the innermost layer and a crosslinked tube 4 as the outermost layer.

[0024]

EFFECTS OF THE INVENTION According to the present invention, in a shielded product of electric wires and cables, a heat-recoverable shield tube having a high shielding property and a high sliding bending resistance and having a beautiful appearance even after shrinkage can be relatively easily obtained. It has been obtained and is widely used.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing before and after contraction of a heat-recoverable shield tube showing one embodiment of the present invention.

FIG. 2 is a schematic diagram showing before and after contraction of a heat-recoverable shield tube showing another embodiment of the present invention in which a conductive resin-containing thermoplastic resin layer is used.

FIG. 3 is a schematic diagram showing before and after shrinkage of a heat-recoverable shield tube showing another embodiment of the present invention, in which a resin layer 1 having a heat-recovery property is arranged in the inner layer of the heat-recoverable shield tube of FIG. is there.

FIG. 4 is a schematic diagram showing a heat-recoverable shield tube according to another embodiment of the present invention in which a cross-linking tube 4 is further arranged in the inner layer of the heat-recoverable shield tube before and after contraction.

FIG. 5 is a heat-recoverable shield tube according to another embodiment of the present invention, in which a heat-recoverable resin layer 1 is arranged in the innermost layer of the heat-recoverable shield tube of FIG. 2 and a cross-linking tube 4 is arranged in the outermost layer. It is a schematic diagram which shows before and behind contraction.

[Explanation of symbols]

 1 Resin layer having heat recovery (heat recovery tube) 2 Thermoplastic resin layer (hot melt adhesive layer) 3 Shield metal layer (aluminum) 4 Crosslinked resin or rubber layer (crosslinked tube)

Claims (3)

[Claims] 1. A heat recovery, characterized in that a layer made of a thermoplastic resin is provided on the inner surface of a layer made of a rubber or a resin having a heat recovery property, and a metal layer is provided between the thermoplastic resin layers. Sex shield tube. 2. The heat-recoverable shield tube according to claim 1, wherein the layer made of a thermoplastic resin contains a conductive filler. 3. A thermoplastic resin layer having a crosslinked resin or rubber layer on its inner surface, and at least one of the resin and / or rubber constituting the innermost layer and the outermost layer has heat recoverability. Heat-recoverable shield tube.