JPH09278910A - Heat shrinkage tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a heat shrinkage tube capable of drawing in high magnification such as fourfold-drawing. SOLUTION: This heat shrinkage tube is prepared by drawing a tube in high magnification which comprises a composition blending 100 pts.wt of a ethylene-α-olefin copolymer allowed to react using a single site catalyst with at least 100-400 pts.wt of an inorganic filler, a carbon black of less than 70 pts.wt. and a softener of less than 100 pts.wt. By blending as the above composition, it is possible to draw in high magnification.

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 which can be stretched at a high draw ratio such as 4 times.

[0002]

2. Description of the Related Art Conventionally, heat-shrinkable tubes include cross-linked polyethylene (PE) and ethylene-propylene rubber (EP
M), ethylene-propylene-gen terpolymer (E
PDM), ethylene-vinyl acetate copolymer (EVA),
Ethylene-ethyl acrylate (EEA) and the like are used. Among them, as a material when electrical insulation and flexible functions are required, due to its excellent physical properties,
The above EPM and EPDM are widely used.

[0003]

However, when the conventional heat-shrinkable tube is stretched, it is usually 100 to 14
Since the heating is performed at about 0 ° C., the above EPM and EPDM have a problem that the elongation at a high temperature is low and it is difficult to stretch at a high magnification (for example, about 4 times).

The present invention has been made in view of such conventional circumstances, and is characterized in that an ethylene-α-olefin copolymer reacted using a single-site catalyst is used as a tube base material. Used by this
It is intended to provide a heat-shrinkable tube stretched at a high ratio.

[0005]

According to the present invention, at least 10 to 400 parts by weight of an inorganic filler and carbon are added to 100 parts by weight of an ethylene-α-olefin copolymer reacted using a single site catalyst. It is a heat-shrinkable tube obtained by stretching a tube made of a composition containing 70 parts by weight or less of black and 100 parts by weight or less of a softening agent at a high ratio.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION As the ethylene-α olefin copolymer (density 0.88 or less) which is used as a base material for a tube in the present invention and which is reacted using a single site catalyst, the above-mentioned EPM, EPDM or the like is used. Can be mentioned. Here, the single-site catalyst means a catalyst having only one active site for promoting the reaction in one catalyst molecule,
As a concrete example, there is a catalyst which is currently called Kaminsky catalyst. This Kaminsky catalyst is composed of a combination of a metallocene compound and methylalumoxane, and it is considered that the metal elements (titanium, zirconium, hafnium, etc.) contained therein have catalytic activity.

In the conventional catalysts for the above-mentioned copolymers, one catalyst molecule usually has a large number of active sites, and the environment around each active site is different, and the active sites are non-uniform (multi-site). It is considered that copolymers having different molecular weights and compositions are produced from the respective active sites, and the obtained copolymers also have a broad molecular weight distribution and composition distribution. On the other hand, in the above single-site catalyst, as compared with the case of this multi-site catalyst, since there is only one active site in one catalyst molecule, the periphery of each active site is made uniform,
Along with this, there is a strong tendency that copolymers having almost the same molecular weight and composition are produced. In other words, a high quality ethylene-α olefin copolymer having a narrow molecular weight distribution and a narrow composition distribution can be obtained.

Examples of the inorganic filler used in the present invention include calcium carbonate and talc, and their blending amount is 10 to 400 parts by weight based on 100 parts by weight of the ethylene-α-olefin copolymer. If the amount is less than 10 parts by weight, the viscosity at the time of extrusion processing is too low, which makes the processing difficult and leads to an increase in cost. On the other hand, if it exceeds 400 parts by weight, the elongation at a high temperature decreases, and it becomes impossible to stretch at a high magnification such as 4 times. In the present invention, in addition to this inorganic filler, 70 parts by weight or less of carbon black is added to reinforce the strength,
Further, in order to ensure the flexibility of the tube, 100 parts by weight or less of a softening agent such as paraffin oil is added. Further, in order to prevent the deterioration of the tube, 0.5 parts by weight or more of an antioxidant such as a phenol type is added, and an organic peroxide (DCP = dicumylperoyside) as a vulcanizing agent is added. . If necessary, a vulcanization acceleration aid (ZnO), an activator (stearic acid), a processing aid and the like may be added.

That is, when an ethylene-α-olefin copolymer reacted using a single-site catalyst was blended with an inorganic filler, carbon black, a softening agent, etc. in such a blending range, the flexibility was improved. Without compromising
A composition capable of being stretched at a high ratio was obtained.

Next, according to the formulation of Table 1, for Examples 1 to 3 of the present invention and Comparative Examples 1 to 3 lacking the conditions of the present invention, elongation at high temperature (120 ° C.), elongation at room temperature, and workability. The test was conducted on the possibility of stretching at high magnification. In Table 1, when stretchable, it is indicated as ◯, and when stretchable is not indicated as x.

[0011]

[Table 1]

From Table 1 above, it is understood that in Examples 1 to 3 of the present invention, the elongation at a high temperature is large and the stretching at a high magnification (4 times) is possible. On the other hand, in Comparative Examples 1 to 3, the elongation at high temperature is small, and it is understood that stretching at a high magnification (4 times) is impossible.

[0013]

As is apparent from the above description, according to the heat shrinkable tube of the present invention, the ethylene-α-olefin copolymer reacted using the single-site catalyst is used as the base material of the tube, and is suitable for this. Since the inorganic filler, the carbon black, the softening agent and the like are blended with the blending ratio of, a heat shrinkable tube stretched at a high ratio can be obtained.

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Claims (1)

[Claims] 1. At least 10 to 400 parts by weight of an inorganic filler, 70 parts by weight or less of carbon black, and 100 parts by weight of a softening agent with respect to 100 parts by weight of an ethylene-α-olefin copolymer reacted with a single-site catalyst. A heat-shrinkable tube obtained by stretching a tube made of a composition containing the following at a high ratio.