JP2001089724A - Pressure-sensitive adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a pressure-sensitive adhesive tape comprising a substrate and a pressure-sensitive adhesive layer formed on the substrate capable of exhibiting a proper adhesive strength in the case of using a halogen free flame retardant resin composition comprising a polyolefin-based polymer as a substrate. SOLUTION: This tape used a silicone based pressure-sensitive adhesive as the pressure-sensitive adhesive layer 2 and the thickness of the layer 2 is 0.05-0.3 mm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive tape used for wiring work of electric wires and cables and the like, which does not generate harmful gas during combustion and has good adhesiveness.

[0002]

2. Description of the Related Art Conventionally, this kind of adhesive tape has a thickness of 0.1 to 0.2 mm made of soft polyvinyl chloride,
A tape-shaped base material having a width of 15 to 30 mm and having an adhesive layer made of a butyl rubber-based adhesive or the like formed on one surface (hereinafter referred to as a PVC adhesive tape) is widely used.

[0003] Meanwhile, there is a movement to stop using vinyl chloride-based plastic, which is a source of dioxin, since environmental issues are now considered important. For this reason, vinyl chloride is also being used for coating materials such as electric wires and cables, and vinyl chloride is being demanded for adhesive tapes used for connection of electric wires and cables.

[0004] In order to satisfy this demand, a resin composition forming a base material of an adhesive tape, a mixture of a polyolefin polymer and a flame retardant of a metal hydroxide such as magnesium hydroxide, is used. A proposal has been made to impart the same level of flame retardancy so that dioxin and halogen-containing gas are not generated during combustion.

However, such a pressure-sensitive adhesive tape made of a polyolefin-based polymer has a problem in that the feeling of use is inferior to that of a pressure-sensitive adhesive tape made of PVC. In particular, the type and thickness of a pressure-sensitive adhesive layer suitable for a substrate made of a polyolefin-based polymer are not known, and the pressure-sensitive adhesive force could not be adjusted to an appropriate range.

[0006]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to determine the type and thickness of a pressure-sensitive adhesive layer suitable for a substrate comprising a flame-retardant resin composition containing a polyolefin-based polymer as a base polymer. It is in.

[0007]

The object of the present invention is to use a polyolefin-based polymer as a base polymer and a specific gravity of 1.14.
Hereinafter, a silicone-based pressure-sensitive adhesive layer having a thickness of 0.05 to 0.3 mm with respect to a substrate made of a halogen-free flame-retardant resin composition having an oxygen index of 24 or more and a heavy metal content of 0.1% by weight or less. Is solved by combining

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
FIG. 1 shows an example of the pressure-sensitive adhesive tape of the present invention. In the figure, reference numeral 1 denotes a base material, and 2 denotes a pressure-sensitive adhesive layer. The base material 1 is obtained by extrusion molding, inflation molding, and calender molding of the flame-retardant resin composition, and has a width of 15 to 30 mm and a thickness of 0.1.
It has a tape shape of about 0.3 mm. The flame-retardant resin composition uses a polyolefin-based polymer as a base polymer and has a specific gravity of 1.14 or less, an oxygen index of 24 or more,
A composition not containing a halogen element such as chlorine, fluorine and bromine having a heavy metal content of 0.1% by weight or less is used.

Specific examples of polyolefin polymers include polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butene-
One or more blended polymers such as one copolymer are used. Among them, ethylene-ethyl acrylate copolymer (50 to 70% by weight) and ethylene-vinyl acetate copolymer (30 to 50% by weight) A polymer blended with the above is preferable because the feeling of hand-cutting of the obtained pressure-sensitive adhesive tape is improved, and a feeling of use equivalent to that of a conventional PVC pressure-sensitive adhesive tape is obtained. Further, in order to obtain an oxygen index of 24 or more, a non-halogen flame retardant is added. As the non-halogen flame retardant, a metal hydroxide such as magnesium hydroxide, aluminum hydroxide, or calcium hydroxide, or a flame retardant auxiliary such as gum-like silicone or silicone resin powder is used.

The amount of the metal hydroxide is from 40 to 50 parts based on 100 parts (parts by weight, hereinafter the same) of the base polymer. If the amount is less than 40 parts, the improvement in flame retardancy is insufficient, and the amount exceeds 50 parts. And the specific gravity exceeds 1.14, and the mechanical strength decreases.
The compounding amount of the flame retardant aid is 5 to 10 parts with respect to 100 parts of the base polymer. When the amount is less than 5 parts, the effect of the addition is not exhibited, and when the amount exceeds 10 parts, the specific gravity increases, which is not preferable.

When the flame retardant resin composition has an oxygen index of less than 24, the flame retardancy is inferior to that of a pressure-sensitive adhesive tape made of PVC and cannot be used as a substitute. In addition, by setting the specific gravity to 1.14 or less, it is possible to perform separation based on the specific gravity from a conventional PVC product. Further, by setting the heavy metal content to 0.1% by weight or less, cadmium, lead, and the like, which are detrimental to the combustion ash, are reduced to the regulated values or less, thereby facilitating disposal. The composition may optionally further contain an antioxidant, a coloring agent, an inorganic filler, an ultraviolet absorber, and the like, if necessary.

The flame-retardant resin composition desirably has a volume resistivity of 10 ¹³ Ω · cm or more, and the resulting adhesive tape has a sufficient electric insulation property and is made of PVC adhesive. It can be used for electrical insulation as well as tape.

The pressure-sensitive adhesive layer 2 has a thickness of 0.05 to
0. mm of a silicone-based pressure-sensitive adhesive. The silicone-based pressure-sensitive adhesive used herein is mainly composed of a mixture of a rubbery polysiloxane and a resinous polysiloxane. In order to further increase the cohesive force, a crosslinked peroxide may be used. . When a silicone adhesive is used, the thickness of the adhesive layer 2 is 0.05 to 0.3.
mm. If it is less than 0.05 mm, the adhesive strength is insufficient,
If it exceeds 0.3 mm, the adhesive strength becomes excessive and the workability is reduced.

The method for producing such a pressure-sensitive adhesive tape is not particularly limited, but the above-described flame-retardant resin composition is kneaded, and the thickness is adjusted to 0.1 to 0.1 mm by extrusion molding, inflation molding, calendar molding, or the like. There is a method in which a 3 mm wide film is manufactured, and the above-mentioned various adhesives are applied to one side of the film to a predetermined thickness by a coating device, and then cut into a width of 10 to 30 mm by a slitter and wound. In this case, by performing a corona treatment, a primer treatment, and the like on the surface of the substrate 1 on which the adhesive is applied,
It is also possible to adopt a method of improving the adhesive strength between the pressure-sensitive adhesive layer 2 and the substrate 1.

In such an adhesive tape, the base material 1 is a resin composition having a polyolefin-based polymer as a base polymer, an oxygen index of 24 or more, a specific gravity of 1.14 or less, and a heavy metal content of 0.1% by weight or less. Since it is made of a material, it exhibits flame retardancy equal to or higher than that of an adhesive tape made of PVC, can be separated from specific polyvinyl chloride products with specific gravity, does not generate harmful substances during combustion, and emits no smoke. Also PVC
Significantly less than adhesive tape. Further, as the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer 2, a silicone pressure-sensitive adhesive is adopted and its film thickness is set to 0.05 to 0.3 mm, so that the self-back surface pressure per 10 mm width of the tape is obtained as described later. The force is 100 gf to 300 gf, showing an adhesive force in a range that is appropriate for use in actual wiring work, etc., it adheres well to electric wires, cables, etc., and the tape can be easily peeled off, resulting in good workability. Become. Furthermore, since the silicone-based pressure-sensitive adhesive itself has good heat resistance, there is no decrease in the adhesive strength of the pressure-sensitive adhesive tape at high temperatures,
It is suitable for use in a high temperature environment up to about 150 ° C.

The following is a specific example. A flame-retardant resin composition having the following composition was prepared, and was blown formed into a film having a thickness of 0.2 mm. Ethylene-ethyl acrylate copolymer 60 parts Ethylene-vinyl acetate copolymer 40 parts Magnesium hydroxide 40 parts Silicone resin powder 5 parts Phenolic antioxidant 0.5 part This resin composition has an oxygen index of 30 and a specific gravity of 1 .14, the heavy metal content was 0% by weight.

On one side of this film, a silicone-based pressure-sensitive adhesive is applied with varying thickness, cut by a slitter,
An adhesive tape having a width of 20 mm was used. The adhesive force of this adhesive tape was measured by a self-back surface adhesive force test. Table 1 shows the results
Shown in

[0018]

[Table 1]

From the results shown in Table 1, it can be seen that when the silicone-based pressure-sensitive adhesive is used, an appropriate pressure-sensitive adhesive strength can be obtained by setting the film thickness to 0.05 to 0.3 mm.

[0020]

As described above, according to the pressure-sensitive adhesive tape of the present invention, it has a flame-retardant performance equal to or higher than that of a conventional PVC pressure-sensitive adhesive tape, and generates harmful substances such as dioxin and halogen-containing gas during combustion. And the amount of smoke generated is small. Further, specific gravity separation from conventional polyvinyl chloride products becomes possible, and waste disposal becomes easy. Further, there are obtained effects such as having an appropriate adhesive force in actual use and improving workability. Also, it has good heat resistance and can be used in a high temperature environment.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an example of an adhesive tape of the present invention.

[Explanation of symbols]

 1. Base material 2. Adhesive layer

Claims (1)

[Claims] 1. A surface of a base material comprising a halogen-free flame-retardant resin composition having a polyolefin-based polymer as a base polymer and a specific gravity of 1.14 or less, an oxygen index of 24 or more, and a heavy metal content of 0.1% by weight or less. And a film thickness of 0.05 to
An adhesive tape provided with a 0.3 mm silicone adhesive layer.