JP2000319600A - Bonding method enabling easy re-separation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the re-separation of a bonded material easily in a short time even at home. SOLUTION: Tacky adhesive layers 1, 1a are formed on both surfaces of a substrate 2 composed of a thermally shrinkable film and adherends A, B are bonded with each other by using the adhesive layers 1, 1a. When the bonded layer of the adherends A, B bonded by the above method is heated, the thermally shrinkable film constituting the substrate 2 is shrunk while peeling the tacky adhesive layers 1, 1a from the bonding face to enable easy re-separation of the bonded material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bonding method that allows an adherend to be re-separated so that a product assembled by bonding a plurality of parts can be easily separated again by material even in a general household after use.

[0002]

2. Description of the Related Art In recent years, there has been an increasing trend to separate and collect waste by material from the viewpoint of resource reuse, and products formed by bonding parts made of different materials are generally used for disposal after use. It is desired that it can be easily re-separated by material even at home.

[0003] For example, a cosmetic mirror made of glass is firmly adhered to a compact cosmetic container using a double-sided adhesive tape or an adhesive. Is difficult to remove unless the adhesive or the adhesive is melted by pouring. Therefore, it is almost impossible to re-separate an adherend such as a makeup mirror in an ordinary household because a solvent that is not always provided must be used.

[0004] As a conventional example, a container constructed by bonding parts made of different materials can be re-separated by material is disclosed in Japanese Patent Laid-Open No.
The technology of 72035 is proposed.

[0005] This container is configured to be adhered with a fixing agent whose adhesive strength is reduced by placing the container in a debonding environment (for example, 60 to 150 ° C) different from a normal use environment. As a specific example of the fixing agent, an adhesive obtained by mixing a foaming agent which foams by heating into an adhesive such as a low molecular olefin adhesive having a certain degree of flexibility even after solidification, a rubber adhesive, or peeling. The use of an adhesive in which microcapsules that dissolve by heating and encapsulating the agent are mixed, or an adhesive that melts when heated is disclosed.

In this conventional example, no matter which fixing agent is used, the mechanical strength and adhesive strength of the adhesive itself are reduced by heating the container body to 60 to 150 ° C. with a drier or the like. Can be removed from the container.

[0007]

According to the above-described bonding method using an adhesive, parts made of different materials can be bonded and re-separated. However, since it is an adhesive method in which an adhesive is applied and solidified, it takes a long time to fix the adhesive, and there is a problem in workability in assembly. In addition, when the adherend is re-separated, the method of expanding bubbles by foaming in the adhesive solidified by heating, or the method of dissolving microcapsules and allowing the release agent to penetrate the bonding surface is considered to be possible to peel off after starting heating. It is anticipated that it will take a considerable amount of time to complete the process, and the method of heating and softening the adhesive is inconvenient because it must be removed while it is hot because it will re-harden if cooled. Also in the case of the above, it is hard to say that it is an easy bonding method to re-separate in a general household.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a bonding method which can be easily re-separated even in a general household without impairing the workability of assembling a product.

[0009]

According to the present invention, there is provided means for solving the above-mentioned problems by forming an adhesive layer on both surfaces of a substrate made of a heat-shrinkable film and bonding an adherend with the adhesive layer. did. When the adherend adhered by such a method is heated, the heat-shrinkable film of the substrate shrinks while peeling the adhesive layer from the adhesive surface, and can be easily separated again.

Further, by using a double-sided pressure-sensitive adhesive tape as the pressure-sensitive adhesive layer, a double-sided pressure-sensitive adhesive layer having a heat-shrinkable film sandwiched between adherends in the bonding step can be formed.

Further, by providing a water-soluble layer made of polyvinyl alcohol between the base material and the adhesive layer, the base material is shrunk with hot water and the water-soluble layer is dissolved to further facilitate the re-separation. Can be.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a preferred embodiment of the present invention will be described. An adhesive layer is formed on both surfaces of a substrate made of a heat-shrinkable film, and an adherend is bonded with the adhesive layer. There is a heat shrinkable film used as a substrate,
One axis of polyethylene, polypropylene, polyester, polyvinyl chloride, polystyrene, polyvinylidene chloride
Alternatively, a biaxially stretched film is used.

The range of the shrinkage temperature of these heat-shrinkable films is generally from 65 to 175 ° C. In order to facilitate the re-separation of the adherend, a film having a high shrinkage rate at 100 ° C. or lower must be used. It is preferred to use.

For the pressure-sensitive adhesive layer of the present embodiment, a rubber-based or acrylic-based pressure-sensitive adhesive conventionally used for a double-sided pressure-sensitive adhesive tape is used. In addition, a water-soluble polyvinyl ether-based pressure-sensitive adhesive can be suitably used. In addition, a conventionally known double-sided adhesive tape is used as it is as an adhesive layer.

In the bonding method according to the present embodiment, an adhesive is applied to both sides of a heat-shrinkable film as a base material in advance, or an adhesive is first applied to release paper and dried, and then the adhesive is heated. Adhesion is performed using a double-sided pressure-sensitive adhesive tape formed with a pressure-sensitive adhesive layer by a transfer method of transferring to a shrink film.

A well-known double-sided pressure-sensitive adhesive tape may be attached to both sides of the heat-shrinkable film to form a pressure-sensitive adhesive layer with a double-sided pressure-sensitive adhesive tape, and this may be used.

Further, after the conventional double-sided pressure-sensitive adhesive tape is attached to each of the adherends, the adherends are bonded with the heat-shrinkable film interposed therebetween, and the double-sided pressure-sensitive adhesive layer is directly applied between the adherends in the bonding step. It may be formed. Alternatively, the adhesive layer may be formed by using the above methods in combination.

Further, a water-soluble layer made of polyvinyl alcohol may be provided between the base material and the adhesive layer. When heated with hot water, the base material shrinks and the water-soluble layer dissolves to further separate the material. Can be easier.

According to the above-mentioned bonding method, the adherend can be assembled by simply pressing the adherend through the three layers of the adhesive layer, the base material and the adhesive layer. It is the same and does not impair workability. Also, when the adherend and the adhesive layer bonded by the present bonding method are heated with a drier or hot water, the heat-shrinkable film of the base material peels off the adhesive layer from the bonding surface and generates wrinkles from the periphery to the center. Shrink toward.

Therefore, when the shrinkage of the base material progresses sufficiently,
The adhesive layer of the base material is linearly adhered at the top of the wrinkles on the shrinking surface, and the adherend can be easily separated again.

In addition, when hot water is used as the heating means, moisture penetrates through gaps between wrinkles generated on the bonding surface between the base material and the adhesive layer due to shrinkage of the base material. It is possible to reduce the adhesive force until the adherends are separated by a slight impact on the body.

When a water-soluble pressure-sensitive adhesive is used or when a water-soluble layer is provided, it is preferable to use boiling water as a heating means.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to a specific embodiment.

Example 1 As shown in FIG. 1, a double-sided pressure-sensitive adhesive tape impregnated with an acrylic pressure-sensitive adhesive and having a thickness of 0.16 mm (manufactured by Sumitomo 3M Limited; No. RTU-2)
5) Adhesive layers 1 and 1a are bonded to both surfaces of a base material 2 made of a heat-shrinkable film having a thickness of 0.05 mm obtained by uniaxially stretching polystyrene, and cut into 25 mm × 25 mm square to form a double-sided adhesive tape. Using this, the adherend A made of a transparent acrylic plate with a thickness of 2 mm (30 mm x 30 mm square)
After adhering adherend B (60 mm x 60 mm square),
The test piece S was obtained by pressurizing with kgf.

(Comparative Example 1) The same adherends A and B as described above were adhered using only a double-sided adhesive tape (manufactured by Sumitomo 3M Limited; No. RTU-25), and then pressurized at 10 kgf. Obtained.

(Comparative Test) Test results obtained by using the test pieces of Example 1 and Comparative Example 1 are shown in Table 1, and reseparability is evaluated.

Each test piece was immersed in a hot water temperature of 96 ° C. and about 1 liter.
The substrates A and B were taken out every minute and manufactured by Imada Seisakusho. F
Type push-pull scale (maximum measured value 10kg, minimum scale 0.1k
In g), the tensile adhesive strength was measured vertically. Note that the adhesive strength before immersion is a reference value because the suction cups adsorbed on the adherends A and B are peeled off first (for example, if the adhesive strength of the mirror of the compact container is 5 kg or more, it can withstand practical use).

[0028]

[Table 1]

(Evaluation) As is apparent from Table 1, the adhesive strength of the test piece S of the example was reduced to 0.3 kg in 5 minutes after immersion. This value is such a strength that the adherends A and B can be lightly pryed open using nails in the re-separation work. During the test, the adhesive layers 1 and 1a partially peeled off from the adherends A and B with the shrinkage of the substrate 2, and the adherends A and B floated apart due to the twist of the substrate 2. The phenomenon of going was confirmed visually from 4 min after immersion. 5 minutes after immersion, the adherends A and B
Was almost peeled off, and it was easy to separate again.

[0030]

The present invention is embodied in the form described above and has the following effects.

According to the bonding method of the present invention, as in the conventional bonding method using a double-sided pressure-sensitive adhesive tape, the assembling work can be performed without impairing the bonding workability. Thus, the adhesive strength can be reduced, and the re-separation work is easily performed.

In addition, since the heat-shrinkable film is used as the base material for the adhesive layer, the heat-shrinkable film is peeled off so that the adhesive surface is reduced due to the shrinkage of the base material, and the adherends are separated from each other. In addition, even if the temperature returns to room temperature, re-adhesion does not occur, and re-separation can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a main part of a test piece bonded by a re-separable bonding method of the present invention.

[Explanation of symbols]

 1, 1a adhesive layer, 2 base material, A, B adherend,

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4F100 AK12A AK25B AK25C AK69E AT00A AT00D BA05 BA06 BA07 BA10B BA10C EJ37 GB71 JA03A JB09E JL05 JL13B JL13C JL14 JL14B JL14C 4J004 AB01 CE01 EA05 4J040

Claims (3)

[Claims] 1. A re-separable adhesion method, comprising: forming an adhesive layer on both surfaces of a substrate made of a heat-shrinkable film; and bonding an adherend with the adhesive layer. 2. The method according to claim 1, wherein said adhesive layer is a double-sided adhesive tape. 3. The bonding method according to claim 1, wherein a water-soluble layer made of polyvinyl alcohol is provided between the base material and the adhesive layer.