JPH08157783A - Preparation of removable pressure-sensitive tape - Google Patents

Abstract

PURPOSE: To enable a pressure-sensitive adhesive tape to be easily and completely removed, upon moistening, without damage to an adherend by providing a particular pressure-sensitive adhesive layer on one or both sides of a substrate. CONSTITUTION: Water in an amount of 50 to 20000 pts.wt. is absorbed into 100 pts.wt. water-absorptive polymer to prepare a water-absorptive polymer with water absorbed thereinto. 0.1 to 100 pts.wt. water-absorptive polymer with water absorbed thereinto is dispersed in 100 pts.wt. pressure-sensitive adhesive, and the dispersion is applied onto one or both sides of a substrate, and the coating is dried to form a pressure-sensitive adhesive layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a removable pressure-sensitive adhesive tape.

[0002]

2. Description of the Related Art An adhesive tape is attached to an article or other adherend for the purpose of display or protection. When the adhesive tape is peeled off after the purpose is achieved, the article or other adherend is damaged. There is a problem such as so-called adhesive residue, in which a part of the adhesive tape is left on the article or the like.

As an attempt to solve these problems, for example, JP-A-56-61468 discloses a pressure-sensitive adhesive tape containing expandable microspheres which expand by heating as an adhesive component. It is said that by irradiating infrared rays at 120 ° C. for about 2 minutes, the adhesive property can be easily lost and peeling can be performed. However, the pressure-sensitive adhesive tape cannot be used for articles or other adherends that are destroyed or deteriorated by heat.

Further, even if the portion where the adhesive tape is adhered is moistened with water, there is no change when the substrate film is a hydrophobic plastic film, and even when it is hydrophilic paper or cellophane, Only the film peels off, leaving the adhesive layer as it is on the article or other adherend.

The present invention has been made in view of the above facts, and an object thereof is to easily peel off by humidification and to give no damage to articles or other adherends. Another object of the present invention is to provide a method for producing a removable pressure-sensitive adhesive tape, which can cleanly remove the adhesive tape.

[0006]

The present invention is characterized in that a pressure-sensitive adhesive layer obtained by dispersing a water-absorbing water-absorbing polymer in a pressure-sensitive adhesive, coating and drying it is provided on one side or both sides of a substrate. The gist of the invention is a method for producing a removable pressure-sensitive adhesive tape.

The substrate used in the present invention includes
It is not particularly limited as long as it is a film-like one,
Used as an adhesive tape, for example, plasticized vinyl chloride resin, polyolefin resin made of polyethylene or polypropylene, plastic film made of polyester resin, paper made of craft paper or Japanese paper,
Examples include cloths made of woven cloth, non-woven cloth and the like, or various base materials in which two or more kinds of the above materials are combined. In particular, a film having a hygroscopic, water-absorbing or water-permeable coating can be preferably used. When the base material used does not have the above performance sufficiently, pores may be provided so as to have hygroscopicity, water absorption or water permeability.

The water-absorbent polymer used in the present invention absorbs water and swells when it comes into contact with water to change into a gel state. At the same time, the once-absorbed gel has a strong water-holding power that does not release water even if some pressure is applied. A water-soluble polymer having a large number of hydrophilic groups is structurally and slightly crosslinked (three-dimensional reticulation) to be insoluble in water.

Examples of these water-absorbent polymers include polyvinyl alcohol, polyhydroxyethyl methacrylate,
Crosslinked water-soluble resin such as polyethylene oxide,
Examples include polymers obtained by graft-polymerizing acrylonitrile on starch and hydrolyzing the polymer, carboxymethylated starch-based starch, starch / acrylate graft-based, isobutylene / maleate-grafted, and the like.

These water-absorbing polymers are available from Arakawa Chemical Industries (trade name: ALASORP) and Kao (trade name: Poise S).
A), Kuraray (trade name: KI gel, aqua beads), Sanyo Chemical Industry (trade name: Sunwet), Sumitomo Chemical (trade name: Sumika Gel), Sekisui Chemical Co., Ltd. (trade name: Aquamate), Toagosei Chemical Industry (Product Name: Alon Zap), Toyobo (Product Name: Lanseal), Nippon Synthetic Chemical Industry (Product Name: Aqua Reserve), Nippon Shokubai (Product Name: Aquaric), Mitsubishi Chemical (Product Name: Dia Wet) It is commercially available from each company.

In the present invention, the blending amount of the above water-absorbing polymer is appropriately set depending on its use and the performance of the water-absorbing polymer used, but is preferably 0 based on 100 parts by weight of the pressure-sensitive adhesive. 0.1 to 100 parts by weight. Even if the blending amount of the water-absorbent polymer is too large, the effect is saturated and rather the adhesive force of the pressure-sensitive adhesive layer is reduced.

Further, the water-absorbent polymer may absorb water before the step of applying and drying the pressure-sensitive adhesive. For example, when the water-absorbent polymer is mixed and dispersed in the pressure-sensitive adhesive, the water-absorbent polymer and water are mixed in advance. Then, the water-absorbent polymer is swollen, and after that, it may be mixed and dispersed with the pressure-sensitive adhesive, but when the pressure-sensitive adhesive is a water-emulsion type, it is added to a water-emulsion type pressure-sensitive adhesive together with a necessary amount of water, The water-absorbent polymer may be swollen with water by stirring and mixing and then dispersed in the pressure-sensitive adhesive.

A pressure-sensitive adhesive tape having a pressure-sensitive adhesive layer obtained from a pressure-sensitive adhesive in which a dried water-absorbent polymer is dispersed in an organic solvent-based pressure-sensitive adhesive is provided on the surface of a base material used in the present invention. Even if it is humidified in the state of being adhered to, the pressure-sensitive adhesive layer does not absorb moisture rapidly and the pressure-sensitive adhesive layer does not substantially expand. Therefore, it is often difficult to easily peel off the adherend.

Based on the above findings, the present inventor investigated the relationship between the water content of the water-absorbent polymer in the pressure-sensitive adhesive layer, the state of swelling of the pressure-sensitive adhesive layer due to humidification, and the pressure-sensitive adhesive force of the pressure-sensitive adhesive layer. It was revealed that it can be used in the range of 50 to 20,000 parts by weight of water based on 100 parts by weight of the polymer.

Since the water-absorbent polymer in the pressure-sensitive adhesive layer is preliminarily absorbed by water and dispersed in the pressure-sensitive adhesive layer, it absorbs water very quickly when immersed in water or humidified by spraying with water. The volume increases, but it is presumed that this is due to the fact that the water absorbability of the water-absorbent polymer increases the wettability of the pressure-sensitive adhesive layer.

In the present invention, the pressure-sensitive adhesive layer may optionally contain a heat stabilizer, a UV absorber, a surfactant, a lubricant,
Coloring agents and other additives may be added without departing from the spirit of the present invention.

In the present invention, the method of providing the pressure-sensitive adhesive layer on the air-permeable base material is not particularly limited, and it may be applied directly to the base material, or applied to a release sheet. Alternatively, the formed pressure-sensitive adhesive layer may be transferred to the base material by a transfer method. The coating device is not particularly limited, and examples thereof include a coater such as a comma coater, a lip coater, a die coater, a doctor blade coater, a bar coater, and a roll coater.

[0018]

The function of the removable pressure-sensitive adhesive tape of the present invention is as follows.
The water-absorbent polymer that has absorbed water is dispersed in a pressure-sensitive adhesive, and the pressure-sensitive adhesive layer obtained by coating and drying is provided on one side or both sides of the substrate, so that the pressure-sensitive adhesive layer expands in volume by humidification, Since the adhesion area at the interface between the layer and the article or other adherend is reduced, the adhesive force at that portion is reduced, and the article can be easily peeled off from the surface of the adherend and no damage is caused to the article or other adherend. The adhesive tape can be peeled off neatly without giving.

[0019]

Embodiments of the present invention will be described below with reference to the drawings.

(Example 1) A water-absorbent polymer (manufactured by Sekisui Plastics Co., Ltd., trade name: Aquamate), which had been previously absorbed under the conditions shown in Table 1, was a solvent-type acrylic adhesive (manufactured by Soken Kagaku Co., Ltd., trade name). : SK-1720) with stirring and dispersion, and applied to the release surface of the peelable sheet so as to have a thickness of 40 μm after drying, and dried to form a pressure-sensitive adhesive layer. Non-woven fabric (made by Hirose Paper Co., Ltd., product name: HO
P30H) to obtain a removable pressure-sensitive adhesive tape.

(Example 2) A water-absorbent polymer (manufactured by Sekisui Plastics Co., Ltd., trade name: Aquamate) which had been previously absorbed under the conditions shown in Table 1 was used as an emulsion type acrylic pressure-sensitive adhesive (manufactured by Soken Kagaku Co., Ltd., trade name). : E-3073) with stirring and dispersion, and applied to the release surface of the release sheet so as to have a thickness of 40 μm after drying, and dried to form a pressure-sensitive adhesive layer. Non-woven fabric (manufactured by Nippon Paper Industries, product name: SS
It was laminated on T) to obtain a removable pressure-sensitive adhesive tape.

Comparative Example 1 The acrylic pressure-sensitive adhesive of Example 1 was applied to the release surface of the peelable sheet in the same manner as in Example 1 and dried to obtain a polyolefin-based nonwoven fabric pressure-sensitive adhesive tape.

Comparative Example 2 The acrylic pressure-sensitive adhesive of Example 2 was applied to the release surface of the peelable sheet in the same manner as in Example 2 and dried to obtain a cellulose nonwoven fabric pressure-sensitive adhesive tape.

The adhesive strength of the pressure-sensitive adhesive tapes obtained in the above Examples 1 and 2 and Comparative Examples 1 and 2 to the stainless steel plate in the normal state and in the wet state is JIS Z 0237.
It measured according to. The condition of moistening and wetting was measured after the test piece was immersed in water for 5 minutes. The measurement results are shown in Table 1.

[0025]

[Table 1]

[0026]

EFFECTS OF THE INVENTION Since the present invention is constructed as described above, the adhesive tape can be peeled off very easily by humidification and without damaging any article or other adherend. A method for manufacturing a peelable adhesive tape can be provided.

Claims (1)

[Claims] 1. A method for producing a removable pressure-sensitive adhesive tape, which comprises providing a pressure-sensitive adhesive layer obtained by dispersing a water-absorbent water-absorbing polymer in a pressure-sensitive adhesive, applying and drying the same on one side or both sides of a substrate. .