JP2801052B2 - Method of manufacturing air-permeable adhesive tape or sheet - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing a gas-permeable pressure-sensitive adhesive tape or sheet used for, for example, a treatment tape or the like, and more specifically, to form pores in a pressure-sensitive adhesive layer. The method relates to an improved process.

[Conventional technology]

The pressure-sensitive adhesive tape used for treatment or the like is required to have appropriate air permeability. If not breathable,
This causes skin irritation and the like.

Therefore, various production methods have conventionally been proposed in order to impart air permeability to the adhesive tape.

For example, Japanese Patent Publication No. 51-8653 discloses a production method using a dispersion liquid in which a gas or liquid having no compatibility with an adhesive is dispersed in the form of fine bubbles or liquid bubbles in an adhesive liquid. ing. In this method, a dispersion liquid is applied to the surface of a release paper so as to have a thickness of 1.2 times or less the diameter of bubbles or liquid bubbles, and heated and dried to form bubbles by causing bubbles or liquid bubbles to form bubbles. ing.

In addition, Japanese Patent Publication No. 58-13116 discloses that an adhesive composition using an organic solvent that can be extracted at room temperature with an aqueous coagulation extract is coated on a gas-permeable support, and then immersed in the extract to remove the organic solvent. A method of extracting and coagulating the pressure-sensitive adhesive composition is disclosed.

Furthermore, Japanese Patent Publication No. 63-41585 discloses a release sheet prepared by uniformly dispersing water or water and a water-absorbing polymer substance in an organic solvent solution of a rubber-based or acrylic pressure-sensitive adhesive. A method of applying, drying and then laminating the porous substrate is disclosed. In this method, by drying the pressure-sensitive adhesive layer in which water is dispersed, water prevents fusion of the adhesive, and an opening is formed in a portion where the water was present.

However, in the method disclosed in JP-B-51-8653 and the method disclosed in JP-B-63-41585,
A dispersion liquid in which a gas or liquid that is not compatible with the pressure-sensitive adhesive is uniformly dispersed to form pores, or a dispersion liquid in which water or water and a water-absorbing polymer substance are uniformly dispersed must be prepared. Must. In addition, in this dispersion, a gas-permeable pressure-sensitive adhesive tape in which pores are uniformly dispersed cannot be obtained unless a state in which bubbles, liquid bubbles, water, and the like are uniformly dispersed is maintained.

As described above, in the conventional method for producing a breathable pressure-sensitive adhesive tape or sheet, preparation of a dispersion liquid and control of the dispersion state were complicated. Further, in terms of air permeability, more excellent ones are required.

[Problems to be solved by the invention]

Accordingly, an object of the present invention is to provide a production method capable of obtaining a pressure-sensitive adhesive tape or sheet having more excellent air permeability by a relatively simple process.

[Means for solving the problem]

As satisfying the above-mentioned problem, the present inventors apply an adhesive solution obtained by dissolving an adhesive in an organic solvent onto a release sheet, and then, while the adhesive solution is in an undried state, water is removed. A method of forming pores in the pressure-sensitive adhesive layer by spraying on the surface and drying was proposed. According to this method, a pressure-sensitive adhesive tape or sheet having air permeability can be obtained by a relatively simple process.

The present inventors studied using the above-described method for producing a novel air-permeable pressure-sensitive adhesive tape or sheet to further enhance air permeability, and dissolved or dispersed a crosslinking agent for crosslinking an adhesive in water to be sprayed. It has been found that excellent results can be obtained if they are set in advance, and the present invention has been accomplished.

That is, the present invention provides a step of preparing a release sheet coated with an adhesive solution in which the adhesive is dissolved in a solvent,
While the pressure-sensitive adhesive solution layer is in an undried state, a step of spraying water in which a crosslinking agent for crosslinking the pressure-sensitive adhesive is dissolved or dispersed on the surface of the pressure-sensitive adhesive solution layer, and then the water is sprayed. A step of drying the pressure-sensitive adhesive solution layer to obtain a pressure-sensitive adhesive layer, and a step of laminating the dried pressure-sensitive adhesive layer with a gas-permeable base material. It is.

As the adhesive used in the present invention, various rubber-based or synthetic resin-based adhesives can be used. For example, an acrylic resin-based pressure-sensitive adhesive containing a carboxylic acid such as acrylic acid or methacrylic acid in a copolymer composition,
An adhesive having a hydroxyl group such as hydroxyethyl methacrylate may be used.

In the present invention, a pressure-sensitive adhesive solution obtained by dissolving the above-mentioned pressure-sensitive adhesive in an appropriate organic solvent is applied on a release sheet. Any release sheet can be used as long as the release sheet has a release property with respect to the pressure-sensitive adhesive. For example, release paper or a release film whose surface is treated with silicone is preferably used.

Spraying water while the pressure-sensitive adhesive solution layer is in an undried state means that water particles enter the pressure-sensitive adhesive solution layer until drying, and water is dispersed by drying the dispersed water. This is because pores are formed in existing portions. Spraying of water can be performed using an appropriate spraying device such as a spray gun. At the time of spraying, water droplets having a particle size of about 10 to 1000 μm
It is sprayed at the rate of to 200 g / m ^2.

The feature of the present invention resides in that a crosslinking agent for crosslinking an adhesive is dissolved or dispersed in water to be sprayed. The cross-linking agent functions to cross-link the surface of the pores formed by drying the water and to keep the shape of the pores stable. That is, it plays a role in preventing the formed pores from being blocked by the fluidity of the adhesive.

Further, when the crosslinking agent is mixed or dispersed in the adhesive solution, the entire adhesive layer is crosslinked and the adhesive strength is reduced. However, in the method of the present invention, the crosslinking agent is dissolved or dispersed only in water. Therefore, there is no danger of lowering the adhesive strength.

Examples of Crosslinking Agent As the above crosslinking agent, various compounds as described below are used.

For example, for an acrylic adhesive containing a carboxylic acid such as acrylic acid or methacrylic acid in its copolymer composition, dimethylol phenol formaldehyde resin, trimethylol melamine, or diamine or polyamine is effective as a crosslinking agent. It is. As the diamine or polyamine that can be used, compounds represented by the following numbers (1) to (12) are considered.

(1) H ₂ N (CH ₂ ) ₂ NH (CH ₂ ) ₂ NH ₂ Further, instead of the crosslinking agent as described above, isocyanate compounds shown in Table 1 below are also effective.

Further, an epoxy compound shown in Table 2 below can be used as a crosslinking agent using a tertiary amine or a quaternary ammonium salt as a catalyst. Further, metal oxides and metal peroxides typified by zinc oxide and zinc peroxide can be used.

It is also possible to use a dicyclopentadiene metal dihalide represented by a general formula of MeCP ₂ Cl ₂ (a metal such as Me: Ti, Zr or Hf, Cp: cyclopentadiene). Further, an organic metal compound represented by a chromium salt of trifluoroacetic acid can be used as a crosslinking agent.

On the other hand, the following compounds are effective as crosslinking agents for pressure-sensitive adhesives having a hydroxyl group such as 2-hydroxyethyl methacrylate. That is, amino resin, RC
l ₂ PO (wherein, R: C ₆ H ₅ −, Cl—CH ₂ −, C ₆ H ₅ O − or C ₂ H ₅
-), An isocyanate compound as shown in Table 1 described above, an acid anhydride such as tetracarboxylic acid anhydride of tetrahydrofuran, pyromellitic anhydride or benzophenonetetracarboxylic acid, glyoxal or Examples include dialdehydes such as terephthalaldehyde, epoxy compounds as shown in Table 2 above, boric acid, various phosphites, and alkoxides of Ti, Zr or Al.

Breathable base material The dried pressure-sensitive adhesive layer is laminated on a breathable base material to form a breathable pressure-sensitive adhesive tape or sheet. As the air-permeable base material, an appropriate one which has been conventionally used for the production of an air-permeable pressure-sensitive adhesive tape or sheet, for example, a synthetic resin nonwoven fabric or the like can be used.

[Function and Effect of the Invention] In the present invention, by a simple process of spraying and drying water on the adhesive solution layer formed on the release sheet,
Pores are formed where water was present. Therefore, a breathable pressure-sensitive adhesive tape or sheet can be obtained by a relatively simple process.

Further, since the crosslinking agent for crosslinking the adhesive is dissolved or dispersed in the water to be sprayed, the vicinity of the surface portion of the pore formed by drying the water is crosslinked by the crosslinking agent. Therefore, the shape of the formed pores is kept stable, and there is no possibility that the pores are closed due to the fluidity of the adhesive layer. Therefore, the air permeability can be effectively increased as compared with the conventional air-permeable pressure-sensitive adhesive tape or sheet.

Moreover, since the crosslinking agent is not dispersed in the entire pressure-sensitive adhesive solution layer, the crosslinking agent does not impair the adhesiveness.

It is pointed out that the production method of the present invention can be suitably used for, for example, a method for producing a medical pressure-sensitive adhesive tape or sheet, but can be generally applied to a method for producing a pressure-sensitive adhesive tape or sheet requiring good air permeability.

〔Example〕

 Hereinafter, non-limiting examples of the present invention will be described.

Example 1 A monomer composition consisting of 90 parts by weight of 2-ethylhexyl acrylate, 4 parts by weight of acrylic acid, 1 part by weight of 2-hydroxyethyl methacrylate, and 5 parts by weight of methyl methacrylate was polymerized with cyclohexane to obtain a solid content.
Adjusted to 40%. The viscosity of this solution is 8000 cp
s.

An adhesive solution obtained by adding 1 part by weight of Coronate L (produced by Nippon Polyurethane Industry Co., Ltd., isocyanate-based crosslinking agent) to the resulting solution was applied onto release paper at a rate of 100 g / m ² , and the adhesive solution was applied. A layer was formed. While the adhesive solution layer was not dried, a 2% by weight aqueous solution of N, N'-hexamethylene-1,6-bis (aziridinecarboxamide) was added at 100 g / m ^2.
And then dried to form an adhesive layer. This pressure-sensitive adhesive layer was transferred to a gas-permeable base material to obtain a gas-permeable pressure-sensitive adhesive tape.

When the air permeability of the obtained air permeable pressure-sensitive adhesive tape was measured using a densometer, it was found that 300 cc of air passed.
It took 1.0 seconds. In addition, when the air permeability was measured in the same manner for one that had been left at 60 ° C for one week, the air permeation time was 1.0
Seconds.

Comparative Example 1 A permeable pressure-sensitive adhesive tape was produced in the same manner as in Example 1. However, in Comparative Example 1, N, N'-hexamethylene-1,6
- instead of the aqueous solution of bis (aziridine carboxyamide), pure water was sprayed at a rate of 100 g / m ^2.

When the air permeability of the obtained air permeable pressure-sensitive adhesive tape was measured with a densometer, it took 1.0 second for 300 cc of air to pass. The air-permeable pressure-sensitive adhesive tape of Comparative Example 1 was heated to 60 ° C.
After one week at a temperature of, the regenerated air permeability was measured, and it took 10 seconds for 300 cc of air to pass.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C09J 7/00-7/04 A61L 15/00-15/64

Claims (1)

(57) [Claims] A step of preparing a release sheet to which an adhesive solution in which an adhesive is dissolved in a solvent is applied; and a step of preparing a release sheet while the adhesive solution layer is in an undried state. Spraying water in which a cross-linking agent that crosslinks the adhesive is dissolved or dispersed; and then drying the pressure-sensitive adhesive solution layer in which the water has been sprayed to obtain a pressure-sensitive adhesive layer. Laminating the agent layer with a gas-permeable base material.