JPH0142984B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a releasable treatment agent that exhibits excellent adhesion even to polyvinyl acetate-long chain alkyl glycidyl ether-based hydrophilic substrates. PRIOR TECHNOLOGY When an adhesive tape is stored in the form of a roll, such as an adhesive tape with an adhesive layer on one side of a base material, and is unwound when used, it is easy to unwind it from its own back side. In order to do this, a releasable treatment layer made of a releasable treatment agent is provided on the back side of the base material. Among the various general performances required of this releasable treatment agent, in particular, the releasable treatment layer does not fall off from the base material (adhesion), and the components in the treatment layer migrate to the adhesive side. It does not contaminate the adhesive surface (prevents reduction in adhesive strength on the adhesive surface), and has a suitable balance between adhesion and peelability to the adhesive surface, preventing deformation such as bamboo shoot phenomenon of rolled tape and adhesive. It is important that no migration phenomenon occurs to the back side of the base material. Conventionally, the releasable treatment agents used are heat-curing silicone-based ones and octadecyl acrylate.
Acrylic acid copolymer-based products (Japanese Patent Publication No. 29-3144), polyvinyl alcohol-octadecyl isocyanate-based products (Japanese Patent Publication No. 7333-1987),
Polyvinyl alcohol-octadecyl isocyanate-polyfunctional isocyanate type (JP-A-Sho
54-56638) were known. Problems to be Solved by the Invention However, heat-curable silicone-based products have problems such as the treatment layer having too much releasability, making it impossible to apply multiple layers and deforming rolled products.Octadecyl acrylate-acrylic Acid copolymer-based materials and polyvinyl alcohol-octadecyl isocyanate-based materials have a problem in that they have poor adhesion to hydrophilic substrates such as cellulose films, resulting in the treated layer falling off from the substrate. On the other hand, polyvinyl alcohol-octadecyl isocyanate-polyfunctional isocyanate-based products, which have been proposed to improve the poor adhesion of the octadecyl isocyanate-based products to the hydrophilic substrate, overcome the adhesion and have the force required for peeling. The problem was that it was large. Means for Solving the Problems The present inventors have overcome the above problems, have satisfactory adhesion even to hydrophilic substrates, and have peeling-adhesion between the back surface of the substrate and the surface of the adhesive. As a result of extensive research in order to develop a releasable treatment agent that can form a well-balanced treatment layer, it was discovered that the objective could be achieved with a polyvinyl acetate-long chain alkyl glycidyl ether type agent, and the present invention was developed. I was able to accomplish this. That is, the present invention provides a stripping treatment agent comprising a reaction product of saponified polyvinyl acetate and a long-chain alkyl glycidyl ether. The saponified polyvinyl acetate used in the present invention preferably has a degree of saponification of 30 to 90%. If the degree of saponification is too low, the layer treated with the releasable treatment agent obtained will have poor releasability, while if it is too high, the reaction completion will be poor and it will be difficult to obtain a uniform reaction product. In addition, as saponified polyvinyl acetate, the average degree of polymerization is 100~
3000 is preferred. If the average degree of polymerization is too low, the resulting layer treated with the release treatment agent will have poor heat resistance, while if it is too high, the reactivity and solubility will be poor, which is not preferred in practice. Used in the present invention, the general formula

[Formula] (R is an alkyl group) Long chain alkyl glycidyl ethers include, for example, hexadecyl glycidyl ether, heptadecyl glycidyl ether, octadecyl glycidyl ether, nonadecyl glycidyl ether, eicosyl glycidyl ether, etc. It is desirable that the alkyl group has 16 to 20 carbon atoms. The strippable treatment agent of the present invention can be used, for example, in an organic solvent.
Saponified polyvinyl acetate and long chain alkyl glycidyl ether obtained by heating in the presence of an alkali to graft a long chain alkyl glycidyl ether onto saponified polyvinyl acetate via its glycidyl group. It consists of the reaction product of The releasability of the treated layer using this releasable treatment agent, and ultimately the release-adhesion balance, is controlled by the proportion of long-chain alkyl glycidyl ether introduced. On the other hand, the introduction ratio of the long-chain alkyl glycidyl ether is determined by the degree of saponification of the saponified polyvinyl acetate and the blending ratio of the long-chain alkyl glycidyl ether to the polyvinyl acetate during the reaction. In the present invention, the ether is used in an equivalent amount to the saponification group of the polyvinyl acetate, and the treatment with a stripping agent provides a reaction method in which the introduction ratio of the ether is controlled by the degree of saponification of the polyvinyl acetate. It is desirable in terms of physical properties and performance such as adhesion of the layer to the hydrophilic base material. From this point of view, it is appropriate that the degree of saponification of the polyvinyl acetate used in the reaction is from 30 to 90%. Application of the releasable treatment agent of the present invention to a base material is as follows:
For example, it is carried out as an organic solvent solution. Effects of the Invention According to the polyvinyl acetate-long chain alkyl glycidyl ether-based releasable treatment agent of the present invention, adhesiveness ( It is possible to form a releasable treated layer that has excellent anchoring properties), is difficult to fall off from the base material, and has excellent peel-adhesion balance. Examples Example 1 In a three-necked flask equipped with a reflux condenser, 20 parts of polyvinyl acetate (parts by weight, hereinafter the same) with a degree of saponification of 88% and an average degree of polymerization of 500 and 205 parts of xylene were placed.
After heating to 120°C, a small amount of xylene solution of potassium hydroxide was added to make the system alkaline, and 117 parts of octadecyl glycidyl ether was added to make the system alkaline.
The reaction was carried out for a period of time to obtain a stripping treatment agent as the desired product. Examples 2 to 5 20 parts of polyvinyl acetate with a degree of saponification of 88% and an average degree of polymerization of 1400 and 117 parts of octadecyl glycidyl ether (Example 2), 20 parts of polyvinyl acetate with a degree of saponification of 88% and an average degree of polymerization of 2300 117 parts of octadecyl glycidyl ether (3), 20 parts of polyvinyl acetate with a degree of saponification of 80% and an average degree of polymerization of 500, and 105 parts of eicosyl glycidyl ether (4), a polyvinyl acetate with a degree of saponification of 80% and an average degree of polymerization of 1400. A stripping agent was obtained in the same manner as in Example 1, except that 20 parts of vinyl acetate and 38 parts of eicosyl glycidyl ether (5 parts) were used. Comparative Examples 1 and 2 20 parts of polyvinyl acetate with a degree of saponification of 88% and an average degree of polymerization of 500 and 105 parts of octadecyl isocyanate (Comparative Example 1), 20 parts of polyvinyl acetate with a degree of saponification of 88% and an average degree of polymerization of 1400 and octadecyl A stripping agent was obtained in the same manner as in Example 1, except that 105 parts of isocyanate (same as 2) was used. Evaluation test Toluene was added to the reaction solution containing the strippable treatment agent obtained in the Examples and Comparative Examples to make a solution with a solid content of 1% by weight, and 0.05 g/g of this was applied to one side of a cellophane film.
A releasable treated film was obtained by applying the coating to a coating amount of m ² and drying it. Next, polyester adhesive tape (manufactured by Nitto Electric Industry Co., Ltd., No.
31B) was pressed by making one reciprocation with a 2 kg roller, and then the adhesive tape was peeled off in a normal state using a 180 degree peel method, and the peeling force at that time was measured. On the other hand, the ability of the treated layer to fall off from the base material was examined by rubbing the treated surface of the film with a finger. The case where there was no falling off was evaluated as ○, and the case where there was some falling off was evaluated as ×. The results are shown in the table.

[Table] It can be seen from the table that the layer treated with the releasable treatment agent of the present invention in Examples has excellent adhesion to the substrate and excellent release-adhesion balance.

Claims (1)

[Scope of Claims] 1. A stripping treatment agent comprising a reaction product of saponified polyvinyl acetate and long-chain alkyl glycidyl ether. 2 Saponified polyvinyl acetate has a saponification degree of 30-90%
The processing agent according to claim 1, which is a treatment agent according to claim 1. 3 Saponified polyvinyl acetate has an average degree of polymerization of 100~
3000. The processing agent according to claim 1. 4. The processing agent according to claim 1, wherein the alkyl group in the long-chain alkyl glycidyl ether has 16 to 20 carbon atoms.