JPS6054854B2 - Adhesion method - Google Patents

Description

[Detailed description of the invention] The present invention relates to a novel bonding method.

In recent years, foams such as polyether urethane, polyester urethane, and polyethylene have been used for earthquake and sound insulation inside coolers, air conditioners, etc., and these foams are made of various resins such as ABS resin, polystyrene, and polyolefin. It is used by adhering it to molded products. Various double-sided adhesive tapes have been used to bond the foam and the molded product, but recently, double-sided adhesive tapes having a water-dispersible adhesive layer have been attracting attention.

However, double-sided adhesive tapes with such water-dispersed adhesive layers lack water resistance and are subject to unfavorable conditions such as moisture from outside air being supplied through the interface between the tape and the foam or through the foam. There is a problem that the oral foam easily peels off because it is used under the skin, and there is a desire to improve this problem.

In view of the state of the prior art, the present inventors have conducted intensive research and found that the problem can be solved by providing a moisture barrier layer made of a specific system at the interface between the tape and the foam.
This led to the present invention. That is, in the present invention, when adhering a foam to an application surface with a double-sided adhesive tape (or sheet) having a water-dispersed pressure-sensitive adhesive layer, a lipophilic heavy-duty polymer having adhesive properties is preliminarily applied to the foam adhesion side of the tape. The present invention provides an adhesive method characterized by providing a coalescing layer.

The water-dispersible pressure-sensitive adhesive used in carrying out the present invention is a dispersion type in which rubber and/or synthetic resin is dispersed, and/or an emulsion type in which synthetic resin is emulsified using an emulsifier. Dispersed pressure sensitive adhesive compositions. Furthermore, the lipophilic polymer used in the practice of the present invention has good adhesion to both the water-dispersed pressure-sensitive adhesive layer and the foam and substantially prevents moisture from entering. There is no particular restriction as long as it can be blocked, but examples include acrylic copolymers, ethylene copolymers, block copolymer rubbers, or crosslinking agents, adhesion-imparting resins, etc. Examples include those containing additives that improve the adhesive strength and cohesive strength of the polymer.

These polymers, such as low molecular weight acrylic oligomers, are mixed with a crosslinking agent, and ethylene copolymers 5, such as ethylene-vinyl acetate copolymer, are heated and melted.
It is preferable to coat the surface of the water-dispersed pressure-sensitive adhesive layer because the treatment can be performed without using an organic solvent or the like. In the double-sided adhesive tape having the water-dispersed pressure-sensitive adhesive layer, it is preferable to use a porous base material such as nonwoven fabric, woven fabric, Japanese paper, or foamed film as a core material, but it is not necessary. When bonding a foam using a double-sided adhesive tape having a water-dispersed pressure-sensitive adhesive layer, a method for forming a lipophilic polymer layer that is provided in advance on the foam adhesion side of the tape is as follows: There is a method in which a layer coating is formed on a release liner, for example, and the coating is transferred to the tape surface when the foam is bonded using the tape, but there is also a method in which the tape is manufactured. Immediately after the tape is produced, a coating can be formed on one of the tapes by coating or laminating a solution of a lipophilic polymer. The thickness ratio between the tape and the lipophilic polymer layer is 1:1 to 0.0.
The thickness of the polymer layer is preferably at least 3 μm (preferably 100 μm or less). If the thickness is less than 3 μm, the tape and the foam will not adhere to each other reliably at the interface, and the polymer layer will not exhibit any significant effects.

The bonding method of the present invention involves bonding a foam using a double-sided adhesive tape having a water-dispersed pressure-sensitive adhesive layer on the application surface.
Since a lipophilic polymer layer is interposed between the tape and the foam that can adhere well to the tape and the foam and substantially block the ingress of moisture, the foam will not peel off from the tape surface over time. It has the following characteristics.

Examples of the present invention will be shown below.

The words "part of the text" indicate parts by weight. Example 1 Polyterpene resin 10 (2) is dissolved in 3 (1) parts of toluene, and then 40 parts of water and 5 parts of an emulsifier are added and stirred to obtain a resin emulsion.

This emulsion is added to and mixed with 20 g of natural rubber latex (low! ammonia type, same type content: 62% by weight) to obtain a natural rubber-based water-dispersed pressure-sensitive adhesive composition.

A rayon nonwoven fabric having a thickness of 40 μm is immersed in this composition bath and dried to obtain a double-sided adhesive tape having a water-dispersed pressure-sensitive adhesive layer having a total thickness of 295 μm.

A commercially available acrylic pressure-sensitive adhesive polymer was coated on one side of this tape to a dry thickness of 5 pm and dried to obtain a two-layer double-sided adhesive tape. Example 2 A commercially available acrylic emulsion type pressure-sensitive adhesive composition was applied to one side of a 40 pm thick rayon non-woven fabric so that the thickness after drying was 40 μm and it showed through. The thickness of the natural rubber pressure-sensitive adhesive polymer after drying is 20 pm.
The mixture was coated and dried to obtain a two-layer double-sided adhesive tape.

Next, apply a thickness of 6Tn! to the polymer layer surface of each of the above tapes. N polyester urethane foams were pasted together and reciprocated with a 2 kg rubber roller to form a sheet with a width of 15 TIfm and a length of 1007 r.
Prepare a sample of fR. This sample has an outer diameter of 50
In order to perform a test to accelerate the interfacial peeling state at the end of the foam and the polymer layer by pasting it in the circumferential direction on the surface of the ABS resin cylinder of T1r1n via a water-dispersed pressure-sensitive adhesive layer, It was stored in a constant temperature room at 50° C., and the lifting distance of the foam terminal was measured.

The results are shown in Table 1.

The comparative example in Table 1 is the measurement result of an acrylic emulsion type pressure sensitive adhesive composition coated on both sides of a rayon nonwoven fabric having a thickness of 40P7TL.

Claims (1)

[Claims] 1 When adhering the foam to the application surface with a double-sided adhesive tape (or sheet) having a water-dispersed pressure-sensitive adhesive layer, a lipophilic polymer layer having adhesive properties is provided in advance on the foam adhesion side of the tape. An adhesion method characterized by: