JPH0858010A - Heat-shrinkable tube - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To provide a heat-shrinkable tube having a metal layer in which deformation of a metal layer is absorbed by a thermoplastic resin layer and has no void, and the surface of the shrinkable tube at the time of heat shrinkage has no wavy state. [Structure] A laminated structure including an inner layer, a heat shrink layer, a thermoplastic resin layer, a metal composite layer, a thermoplastic resin layer, and a heat shrink layer,
The MI value of the resin forming the thermoplastic resin layer is 10 g / 10
min (JIS K6730) or more, the thickness of the thermoplastic resin layer is 0.1 mm or more and 1 mm or less, and the metal thickness of the metal composite layer is
A heat-shrinkable tube having a shrinkage temperature of 0.001 mm or more and 0.1 mm or less and a shrinkage temperature of the inner heat-shrinkable layer higher than that of the outer heat-shrinkable layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat-shrinkable tube having a metal layer in the middle, which is used for waterproof protection of a connecting portion such as a cable and for electric shield.

[0002]

2. Description of the Related Art Conventionally, the problems to be solved by the invention
For the waterproof protection of the cable connection part, a metal tape is wound around the connection part and then a heat shrinkable tube is coated on the metal tape, but there is a problem that work efficiency is poor. Therefore, a heat-shrinkable tube having a metal layer as an intermediate layer has been proposed (see, for example, Japanese Patent Publication No. 1-18862). But with this structure,
Since the metal layer does not shrink due to heating, the heat shrink layer of the inner layer shrinks first and a gap is created between it and the metal layer, and then the outer shrink layer shrinks and the stress also shrinks the metal layer. There is a problem in that a gap is generated, and the surface of the shrink tube after the heat shrink is in a wavy state.

[0003]

SUMMARY OF THE INVENTION The present invention solves the above problems and provides a heat-shrinkable tube having a metal layer which has no voids due to deformation of the metal layer and has no wavy state on the surface of the shrinkable tube after heat shrinking. The first feature of the present invention is to provide a laminated structure of an inner layer to a heat shrinkable layer, a thermoplastic resin layer, a metal composite layer, a thermoplastic resin layer, and a heat shrinkable layer, and a resin constituting the thermoplastic resin layer. MI value of 10g / 10min (JIS K
6730) or more, the thickness of the thermoplastic resin layer is 0.1 mm or more and 1 mm or less, the metal thickness of the metal composite layer is 0.001 mm or more and 0.1 mm or less, and the shrinkage temperature of the inner heat-shrinking layer is less than that of the outer layer. It is higher than the shrink temperature of the heat shrink layer.

The second feature of the present invention is that it comprises a laminated structure of an inner layer, a heat shrink layer, a thermoplastic resin layer, a metal composite layer, a thermoplastic resin layer and a heat shrink layer, and constitutes the thermoplastic resin layer. The MI value of the resin is 10 g / 10 min (JIS K6730) or more, and the thickness of the thermoplastic resin layer is 0.1 mm or more and 1 mm or less,
The metal composite layer has a metal thickness of 0.001 mm or more and 0.1 mm or less, and the metal composite layer is a heat-shrinkable tube composed of a laminated resin film and a metal.

[0005]

The function of the heat shrinkable tube of the present invention is from the inner layer to the heat shrinkable layer,
Since it has a laminated structure of a thermoplastic resin layer, a metal composite layer, a thermoplastic resin layer, and a heat-shrinkable layer, the thermoplastic resin is in a state of being melted and confined in the inner and outer heat-shrinkable layers during heat shrinkage, and the metal is bent. However, since the thickness of the upper and lower thermoplastic resin layers is absorbed, the wavy state does not occur on the surfaces of the inner and outer layers.

Examples of the thermoplastic resin include polyolefins such as polyethylene, ethylene vinyl acetate copolymer, ethylene ethyl acrylate copolymer, ethylene methyl acrylate copolymer and the like, acid anhydrides thereof, polyamide, polyester and the like. It is necessary that it can be used, is melted during heat shrinkage, makes the metal easily bent, and is not crosslinked to fill the gap. In order to fill the gap, the MI value of the thermoplastic resin should be 10g / 10min or more.
Below this, it is difficult to bend the metal during heat shrinkage, and it is difficult to completely fill the gap. further,
It is desirable that the thickness of the thermoplastic resin layer is 0.1 mm or more and 1 mm or less. If it is less than 0.1 mm, it is not enough to absorb the bending of the metal, and if it exceeds 1 mm, the heat shrinking layer is sufficiently melted during heat shrinkage. It is difficult to completely fill the gap without entering the state.

The heat-shrinkable layer is formed by crosslinking polyolefin such as polyethylene, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, and ethylene-acryl-methyl acetate copolymer by electron beam or chemical crosslinking. The thickness of each heat-shrinkable layer is not particularly limited, but it is necessary that the surface does not wavy during heat shrinkage, and a thickness of 0.1 mm or more is preferable. However, if it is 5 mm or more, it becomes too thick and the time required for heat shrinkage becomes long.

As the metal of the metal composite layer, lead, aluminum, copper or the like can be used. The thickness needs to be easily bent in the thermoplastic resin during heat shrinkage,
If it is 0.1 mm or less, 0.001 mm or more is preferable so that the shield can be completely realized even if wrinkles occur after contraction. As a material to be laminated on these metals, an unstretched film or stretched film of polyethylene, vinyl chloride, polyester or the like is used.

When a laminate of unstretched films is used as the metal composite layer, the heat shrinkable layer must have a shrinkage temperature of the inner layer higher than that of the outer layer. When the shrinkage temperature of the inner layer is the same as or lower than the shrinkage temperature of the outer layer, the shrinkage of the heat shrinkage layer of the outer layer is delayed due to the resistance of the metal layer during heat shrinkage, during which heat is transferred to the heat shrinkage layer of the inner layer and the inner layer shrinks faster. However, peeling occurs at the interface between the metal layer and the inner shrink layer, and large wrinkles occur at the peeled portion.

When a metal laminated with a stretched film is used as the metal composite layer, the stretched film easily shrinks during heat shrinkage, and the metal also bends following it, so that the shrinkage stress of the heat shrinkable layer is particularly large. The shrinkage temperature of the inner heat shrinkable layer and the outer heat shrinkable layer is not particularly limited.

The heat-shrinkable layer can be formed from a stretched sheet other than a stretched tube. In the case of a tube, a thermoplastic resin layer and a metal composite layer are wrapped. In the case of a sheet, a known method can be used for forming a tube such as laminating the layers necessary for the constitution and then laminating the ends to form a tube. The heat-shrinkable tube of the present invention can be adhered to an adherend by providing a thermoplastic resin layer that adheres to the adherend inside the inner heat-shrinkable layer.

[0012]

EXAMPLE FIG. 1 is a cross-sectional view of a specific example of the heat-shrinkable tube of the present invention, FIGS. 2A and 2B are cross-sectional views of the metal composite layer of the present invention, and FIG. 3 is a heat-shrinkable tube of the present invention. It is a transverse cross-sectional view of the contraction of. In the drawings, 1 is an inner heat shrink layer,
Reference numeral 2 is an inner layer thermoplastic resin layer, 3 is a metal composite layer, 4 is an outer layer thermoplastic resin layer, and 5 is an outer layer heat shrink layer. As shown in FIG. 2, the metal composite layer 3 has an unstretched film or stretched film of polyethylene, vinyl chloride, polyester or the like on one or both sides of the metal foil 31 of lead, aluminum, copper or the like.
32 is laminated, and when the unstretched film is laminated as described above, the shrinkage temperature of the inner heat-shrinkable layer 1 needs to be higher than that of the outer heat-shrinkable layer 5, When the stretched film is laminated, the shrinkage temperature of the heat shrinkable layer of the inner and outer layers is not particularly specified. Further, as described above, the heat-shrinkable tube of the present invention can be bonded to the adherend by providing the inner heat-shrinkable layer 1 and the thermoplastic resin layer on the inner side for adhering to the adherend.

When the heat-shrinkable tube of the present invention is shrunk as described above, the thermoplastic resin layer is melted and confined in the inner and outer heat-shrinkable layers as shown in FIG. The thickness of the thermoplastic resin layer absorbs this,
There is no gap and no waviness on the inner and outer surfaces.

[0014]

[Prototype example]

(Example 1) A metal rod having an outer diameter of 135 mm wound with Teflon tape and having an inner diameter doubled to have an inner diameter of 140 mm and an outer diameter of 1
After inserting a 44 mm polyethylene heat-shrinkable tube and heat-shrinking it, a 0.3 mm-thick sheet of thermoplastic ethylene-vinyl acetate copolymer is wound around the surface of the heat-shrinkable tube once in the circumferential direction. Similarly, a laminated film of 0.05 mm thick lead foil and 0.05 mm thick polyethylene is wound so as to be overlapped by 10 mm, and the above-mentioned thermoplastic ethylene vinyl acetate copolymer sheet is further wound thereon. And the inner diameter
Insert an outer layer heat-shrink tube of ethylene vinyl acetate copolymer with an inner diameter of 150 mm and an outer diameter of 155 mm stretched 2.5 times,
A heat-shrinkable tube of the present invention having a continuous laminated structure was produced by heat-shrinking at a temperature of 1 ° C (claim 1). This heat-shrinkable tube was inserted into the outer circumference of a pipe having an outer diameter of 100 mm and heat-shrinked at 120 ° C. The surface of the shrink tube after heat shrink is smooth,
It was confirmed that the wavy state due to the deformation of the lead foil was absorbed by the thermoplastic resin layer.

(Embodiment 2) A metal rod having an outer diameter of 135 mm wound with Teflon tape and having an inner diameter doubled 1
Insert a heat-shrinkable tube of 40 mm in outer diameter and 144 mm in inner diameter of ethylene-vinyl acetate copolymer to shrink heat, and then wrap a 0.3 mm-thick sheet of thermoplastic ethylene-vinyl acetate copolymer on the surface of the heat-shrinkable tube. Wind once in the direction. Thickness on this
A laminated film of an aluminum foil of 0.05 mm and a vinyl chloride stretched 1.5 times the thickness of 0.05 mm is wound in the same manner so as to be overlapped by 10 mm, and further, the above-mentioned thermoplastic ethylene vinyl acetate copolymer sheet is wound thereon. Then, insert a heat-shrink tube of an outer layer of ethylene-vinyl acetate copolymer of the same material as the inner layer with an inner diameter of 150 mm and an outer diameter of 155 mm with the inner diameter stretched 2.5 times, and heat-shrink at 100 ° C to continuously A heat-shrinkable tube of the present invention having a laminated structure was produced (claim 2). This heat-shrinkable tube was inserted into the outer circumference of a pipe having an outer diameter of 100 mm and heat-shrinked at 120 ° C. It was confirmed that the surface of the shrinkable tube after the heat shrinkage was smooth, and the wavy state due to the deformation of the aluminum foil was absorbed by the thermoplastic resin layer.

(Comparative Example) A metal rod having an outer diameter of 135 mm wound with Teflon tape and having an inner diameter doubled to have an inner diameter of 140 mm.
After inserting a heat-shrinkable tube of the inner layer of ethylene-vinyl acetate copolymer having an outer diameter of 144 mm and an outer diameter of 144 mm to cause heat-shrinkage, the surface of the heat-shrinkable tube was wrapped around a 0.3 mm-thick sheet of thermoplastic ethylene-vinyl acetate copolymer. Wind once in the direction. On top of this, the thickness
Similarly, a laminated sheet of 0.05 mm lead foil and 0.05 mm thick polyethylene is wound so as to be overlapped by 10 mm, and the above-mentioned thermoplastic ethylene vinyl acetate copolymer sheet is further wound thereon. Then, insert a heat-shrink tube of an outer layer of the same ethylene vinyl acetate copolymer as the inner layer with an inner diameter of 150 mm and an outer diameter of 155 mm with the inner diameter stretched 2.5 times, and heat-shrink at 100 ° C to form a continuous laminated structure. A heat-shrinkable tube was prepared. This heat-shrinkable tube was inserted into the outer circumference of a pipe having an outer diameter of 100 mm and heat-shrinked at 110 ° C. At this time, after the heat-shrinkable layer of the inner layer shrinks first to form a large gap with the metal layer,
The heat-shrinkable layer as the outer layer contracted together with the metal layer, and a large gap was partially formed. Therefore, the surface of the shrinkable tube after the heat shrinkage was wavy.

[0017]

As described above, according to the heat-shrinkable tube of the present invention, the deformation of the metal layer is absorbed by the thermoplastic resin layer and there is no void, and the surface of the heat-shrinkable shrinkable tube has a wavy state. A heat shrink tube with no metal layer can be realized. Therefore, it is effective when it is used for waterproof protection of a connecting portion such as a cable or electrical shield, and is extremely effective especially when connecting a cable which is required to be waterproof.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a specific example of a heat-shrinkable tube of the present invention.

2A and 2B are cross-sectional views of a metal composite layer according to the present invention.

FIG. 3 is a cross-sectional view of the heat-shrinkable tube of the present invention at the time of shrinking.

[Explanation of symbols]

 1 Inner layer heat shrink layer 2 Inner layer thermoplastic resin layer 3 Metal composite layer 4 Outer layer thermoplastic resin layer 5 Outer layer heat shrink layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location F16L 11/12 H02G 15/18

Claims (3)

[Claims] 1. A laminate structure comprising an inner layer, a heat-shrinkable layer, a thermoplastic resin layer, a metal composite layer, a thermoplastic resin layer, and a heat-shrinkable layer. The MI value of the resin constituting the thermoplastic resin layer is 10 g.
/ 10 min (JIS K6730) or more, the thickness of the thermoplastic resin layer is 0.1 mm or more and 1 mm or less, the thickness of the metal of the metal composite layer is 0.001 mm or more and 0.1 mm or less, and the shrinkage of the inner heat-shrinkable layer A heat-shrinkable tube characterized in that the temperature is higher than the shrinkage temperature of the outer heat-shrinkable layer. 2. A laminate structure comprising an inner layer, a heat shrink layer, a thermoplastic resin layer, a metal composite layer, a thermoplastic resin layer and a heat shrink layer, wherein the MI value of the resin constituting the thermoplastic resin layer is 10 g.
/ 10 min (JIS K6730) or more, the thickness of the thermoplastic resin layer was 0.1 mm or more and 1 mm or less, the metal thickness of the metal composite layer was 0.001 mm or more and 0.1 mm or less, and the metal composite layer was stretched. A heat-shrinkable tube, which is made of a laminate of a resin film and a metal. 3. The heat-shrinkable tube according to claim 1, wherein the innermost layer is provided with a thermoplastic resin layer.