JP2001240818A - Nonhalogen flame-retardant adhesive tape - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a nonhalogen flame-retardant adhesive tape having reliable heat resistance. SOLUTION: This nonhalogen flame-retardant adhesive tape has a heat insulating layer installed on the front side of a nonhalogen flame-retardant film in the nonhalogen flame-retardant adhesive tape obtained by arranging an adhesive layer on the back side of the nonhalogen flame-retardant film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a halogen-free flame-retardant pressure-sensitive adhesive tape used for bundling and terminating electric wires.

[0002]

2. Description of the Related Art Conventionally, PVC resin has been used as a flame-retardant pressure-sensitive adhesive tape which is required to be particularly flame-retardant for use in automobiles. However, non-halogenation has been promoted so that no harmful gas is generated at the time of final treatment. Have been

As such a non-halogen flame-retardant adhesive tape, an ethylene-ethyl acrylate copolymer (EE)
A), a film made of a resin mixture obtained by adding a large amount of an inorganic flame retardant such as magnesium hydroxide using an ethylene-vinyl acetate copolymer (EVA) or the like, and then forming a tape after providing an adhesive layer. Is common.

[0004] However, when an ethylene-vinyl acetate copolymer or an ethylene-ethyl acrylate copolymer is used, the vinyl acetate component or the ethyl acrylate component has low heat resistance and is easily deformed. Therefore, when it is used in a place where relatively high heat is likely to occur (for example, in an engine room or a trunk room of an automobile), it has been difficult to apply it to a field requiring particularly high reliability, such as a binding tape of a bundled electric wire. .

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems, that is, a highly reliable non-halogen flame-retardant adhesive which has excellent heat resistance and does not cause inconvenience such as deformation even at a relatively high temperature. It is intended to provide a tape.

[0006]

According to the present invention, there is provided a non-halogen flame-retardant pressure-sensitive adhesive tape having an adhesive layer disposed on the back side of a non-halogen flame-retardant film. In the burning adhesive tape,
This is a halogen-free flame-retardant pressure-sensitive adhesive tape in which a heat insulating layer is provided on the surface side of the halogen-free flame-retardant film.

That is, the structure in which the heat-insulating layer is provided on a surface different from the side of the adhesive layer in the non-halogen flame-retardant film allows the non-halogen flame-retardant adhesive tape to be wound around the surface of an electric wire bundle or the like. Since the high temperature does not reach the halogen-free flame-retardant film, the deformation of the halogen-free flame-retardant film is prevented, and the viscosity of the pressure-sensitive adhesive of the pressure-sensitive adhesive layer is also prevented from extremely lowering, so that the adhered state is maintained.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the halogen-free flame-retardant pressure-sensitive adhesive tape of the present invention, the base film must be a film made of a halogen-free flame-retardant resin. Here, a halogen-containing resin such as a PVC resin may generate harmful substances such as dioxin at the time of final disposal.

Such a film is, for example, an ethylene-ethyl acrylate copolymer 10 which is an olefin resin.
An inorganic flame retardant (such as magnesium hydroxide) is usually added in an amount of 50 to 150 parts by weight with respect to 0 parts by weight so that sufficient flame retardancy can be obtained.
Parts by weight, preferably 100 parts by weight, are uniformly kneaded by a twin-screw kneader or the like, and then granulated as necessary.

Using the obtained halogen-free flame retardant resin, T
Extrusion molding is performed by a die method or an inflation method to form a halogen-free flame-retardant resin film. At this time, the thickness of the film is 0.100 mm or more and 0.130 mm or less,
Preferably, it is set to about 0.115 mm. That is, if it is too thick than 0.130 mm, it is hard and hard to break off, and it is too soft than 0.100 mm and hard to break off.

The heat-insulating layer in the present invention is formed on one surface of the film made of the non-halogen flame-retardant resin, that is, on a surface different from the adhesive layer, and on the surface side in normal use. Here, when formed on the same surface as the adhesive layer, the heat resistance is poor, and as a result, the effects of the present invention cannot be obtained.

In the present invention, the heat insulating layer is made of a mixture of an inorganic heat insulating material and a resin. The resin used here is appropriately selected from those that function as a paint, but the acrylic emulsion resin is available in the form of an aqueous emulsion, and therefore is very easy to mix with ceramic bubbles, and after mixing. There is an advantage that handling such as dilution is easy. Further, applying a mixture of an acrylic emulsion resin and an inorganic heat insulating material to a film does not require large-scale equipment.
Further, acrylic emulsion resins are excellent in light resistance, chemical resistance, water resistance, and moisture resistance. Furthermore, since it has no halogen, final disposal is easy. Therefore, the halogen-free flame-retardant pressure-sensitive adhesive tape of the present invention can have these properties.

The inorganic heat insulating material is preferably a ceramic bubble (small sphere) having a hollow structure. A ceramic bubble is a very fine ceramic sphere and is hollow. In addition, when such a ceramic bubble is used, a particularly high heat resistance can be obtained by using a ceramic bubble having a vacuum in the hollow portion.

Here, a paint in which about 60% of the volume is a hollow portion and a ceramic bubble having a vacuum in the hollow portion is previously mixed with an acrylic aqueous emulsion resin is commercially available. It is available from special paints.

The above-mentioned vacuum in the hollow portion means that the pressure is lower than that of a normal environment, and it is desirable that the pressure be about 200 to 400 hpa or less in order to have sufficiently high heat insulation. .

On the other hand, as the pressure-sensitive adhesive forming the pressure-sensitive adhesive layer, a conventionally used pressure-sensitive adhesive can be used as it is, as long as it has the required heat resistance, non-halogenity, and the like. For example, nitrile rubber, styrene-butadiene rubber, acrylate ester and rosin ester are mixed at an appropriate mixing ratio, and the surface opposite to the heat-insulating layer of the film made of non-halogen flame-retardant resin, the back surface in normal use. The final coating thickness is 0.02-
Coating is performed so as to be 0.04 mm, preferably 0.03 mm. At this time, if the coating thickness is too large, peeling, cracks and the like are likely to occur, while if too thin, the effect as a heat insulating layer cannot be obtained.

After the heat-insulating layer is formed on the front side of the non-halogen flame-retardant film and the pressure-sensitive adhesive layer is formed on the rear side, the film is cut into a required width (for example, about 19 mm) to obtain a non-halogen flame-retardant pressure-sensitive adhesive tape.

Here, a cross section of the non-halogen flame-retardant pressure-sensitive adhesive tape of the present invention and a cross section of a conventional non-halogen flame-retardant pressure-sensitive adhesive tape are modeled in FIGS. 1 and 2, respectively. As apparent from these figures, the non-halogen flame-retardant pressure-sensitive adhesive tape of the present invention, when used, has a non-halogen flame-retardant film serving as a base, which is thermally insulated by the heat insulating layer disposed on the surface opposite to the adhesive layer, that is, on the surface side. It has extremely excellent heat resistance because it is protected.

[0019]

The non-halogen flame-retardant adhesive tape of the present invention is described below.
Will be specifically described. Halogen-free flame retardant of the present invention
The film used for the adhesive tape is non-halogen
Ethylene-ethyl ac
Related copolymer A1150 (melt index (M
I): 0.75, ethyl acrylate unit content
(EAcont): 15% by weight) (hereinafter also referred to as "EEA")
100 parts by weight and magnesium hydroxide (Kyowa Chemical)
Manufactured by Kisuma 5A) (hereinafter “Mg (OH) _Two")
100 parts by weight with a twin-screw kneader to mix and knead
Extrusion molding of halogen flame-retardant resin using T-die,
A halogen-free flame-retardant film with a thickness of 0.115 mm was obtained.
Was.

A heat insulating layer was provided on one side (front side) of the non-halogen flame-retardant film. An acrylic water-based emulsion paint (Nagashima special paint acid-coated thermoshield) in which 60% of the volume is a hollow portion and a ceramic bubble whose vacuum portion is evacuated is added as an inorganic heat insulating material (hereinafter referred to as an "acid-coated thermoshield") Paint α) as it is or diluted with the same volume or 9 times the volume of water to form three types of coating liquids, uniformly applied, and a non-halogen flame-retardant adhesive film (three types) having a heat insulating layer. Obtained.

In the non-halogen flame-retardant pressure-sensitive adhesive films (three kinds) having the heat-insulating layer, the surface opposite to the heat-insulating layer, that is, the back surface side, is used as an adhesive layer for nitrile rubber, styrene-styrene.
A butadiene rubber, an acrylate ester and a rosin ester are blended at a weight ratio of 30, 30, 20, and 20, respectively, and a mixed pressure-sensitive adhesive is applied so as to have a thickness of about 0.04 mm. This was cut to obtain a halogen-free flame-retardant pressure-sensitive adhesive tape (Examples 1 to 3) according to the present invention.

In addition, an adhesive was similarly applied to one side of the non-halogen flame-retardant pressure-sensitive adhesive film having no heat-insulating layer to obtain a non-halogen flame-retardant pressure-sensitive adhesive film having no heat-insulating layer (Comparative Example 1).

With respect to these four types of non-halogen flame-retardant pressure-sensitive adhesive tapes (Examples 1 to 3 and Comparative Example 1), two types of heat resistance A and B were evaluated. As the heat resistance A, a sample was prepared by winding a tape around a steel rod having a diameter of 10 mm so that the width directions of the tape overlap each other by １ ／, and the shape of the tape after being kept in air at 120 ° C. for 96 hours was examined. In addition, this winding binds automobile electric wires (manufacture of harness)
It was performed assuming that

As the heat resistance B, similarly to the heat resistance A evaluation, the width direction of the tape was 1/1 /
The sample was wound by overlapping two by two, and the shape of the tape after being exposed to Bunsen burner flame for 30 seconds was examined.

In the evaluation, the heat resistance A and the heat resistance B were evaluated as “「 ”when there was no change in the shape,“ ○ ”when the shape was slightly changed, and“ を ”when the shape was clearly changed. “△”, a case where the shape changed significantly and the shape as a tape was not maintained was evaluated as “×”. Table 1 shows the evaluation results.

[0026]

[Table 1]

Table 1 shows that the halogen-free flame-retardant pressure-sensitive adhesive tape according to the present invention has extremely high heat resistance, and sufficient reliability can be obtained even when used for applications such as binding electric wires. The non-halogen flame-retardant pressure-sensitive adhesive tape according to the present invention did not cause any trouble such as peeling of the heat-insulating layer at normal handling, rubbing strongly with the fingers of the hand, or peeling off the pressure-sensitive adhesive surface.

[0028]

When the non-halogen flame-retardant pressure-sensitive adhesive tape of the present invention is used, the base non-halogen flame-retardant film is thermally protected by the heat-insulating layer disposed on the surface opposite to the adhesive layer, that is, on the surface side. Therefore, it has extremely excellent heat resistance. Therefore, it is an excellent non-halogen flame-retardant pressure-sensitive adhesive tape which can be sufficiently applied in fields requiring extremely high reliability, such as bundling of electric wire bundles in an engine room of an automobile or terminal treatment of electric wires.

[Brief description of the drawings]

FIG. 1 is a model sectional view of a halogen-free flame-retardant adhesive tape of the present invention.

FIG. 2 is a model sectional view of a conventional halogen-free flame-retardant adhesive tape.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4J002 BG001 DM006 FA106 FD206 GJ01 GQ00 HA07 4J004 AA05 AA07 AA10 AB01 CA04 CA07 CC05 CD05 FA05 4J038 CG141 HA566 KA12 KA21 MA10 NA15 PB09 PC08

Claims (4)

[Claims] 1. A non-halogen flame-retardant pressure-sensitive adhesive tape having an adhesive layer disposed on the back side of a non-halogen flame-retardant film, wherein a heat insulating layer is provided on the front side of the non-halogen flame-retardant film. Adhesive tape. 2. The non-halogen flame-retardant pressure-sensitive adhesive tape according to claim 1, wherein the heat-insulating layer comprises an acrylic water-based emulsion resin and a granular inorganic heat-insulating material having a hollow structure. 3. The non-halogen flame-retardant pressure-sensitive adhesive tape according to claim 2, wherein the granular inorganic heat insulating material having a hollow structure is made of ceramic. 4. The non-halogen flame-retardant pressure-sensitive adhesive tape according to claim 2, wherein the inside of the granular inorganic heat insulating material having a hollow structure is evacuated.