JPS61271373A - Strippable treating agent - Google Patents

Abstract

PURPOSE:To provide the titled treating agent having excellent heat resistance and adhesion to hydrophilic substrates and well-balanced properties between stripping and bonding, by reacting a saponified polyvinyl acetate with a long- chain alkylaldehyde. CONSTITUTION:A long-chain 16-20C alkyl-aldehyde (e.g. octadecylaldehyde) is grafted onto a saponified polyvinyl acetate having a degree of saponification of 30-90% and an average degree of polymn. of 100-3,000 by heating in an org. solvent (e.g. xylene) in the presence of an acid (e.g. HCl) to obtain a strippable treating agent. The agent is dissolved in an org. solvent and applied to a substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention provides a releasable treatment agent that has excellent adhesion to polyvinyl acetate-long chain alkyl aldehyde-based hydrophilic substrates and has excellent heat resistance. It is related to.

Conventional technology: For products that are stored in the form of rolls, such as adhesive tags, which are made by providing an adhesive layer on one side of a base material, and are unwound when used, it is easy to unwind the self-back side. In order to achieve this, a releasable treatment layer made of a releasable treatment agent is provided on the back side of the base material.

Among the general properties 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 (ability to prevent adhesive strength from decreasing on the adhesive surface), maintains smooth unwinding performance over time (removability maintenance), and maintains adhesiveness to the adhesive surface. The peelability is moderately balanced, and there is no deformation of the rolled tape such as bamboo shoot phenomenon, no migration of the adhesive to the back side of the base material, and there is little change in performance even when subjected to thermal history. (heat resistance) etc. are important.

Conventionally, the release treatment agents used include heat-curing silicone-based agents, polyvinyl alcohol-octadecyl isocyanate-based agents (Japanese Patent Publication No. 7333-1983), and polyethyleneimine-octadecyl isocyanate-based agents (No. 17661-1973). Publications), active hydrogen-containing polymers based on octadecyl isocyanate (Japanese Patent Publication No. 34
-3382), etc. were known.

Problems to be Solved by the Invention However, heat-curing silicone-based products have a treatment layer that is too strong in releasability, resulting in problems such as overlapping cine performance and deformation of rolled products. −
Others such as octadecyl isocyanate type K
It has poor heat resistance, such as the force required for unwinding greatly increases when subjected to thermal history such as high temperature storage, and has poor adhesion to hydrophilic substrates such as cellophane-based substrates, making it easy to remove from the substrate. There was a problem with it falling off.

Means for Solving the Problems The present inventors have overcome the problems described above, and have achieved satisfactory adhesion even to hydrophilic substrates, heat resistance, and adhesive properties on the back side of the substrate.
As a result of repeated research on the amount of lead in order to develop a releasable treatment agent that can form a treatment layer with excellent peel-adhesion balance between adhesive surfaces, we found that a polyvinyl acetate-long chain alkyl aldehyde-based agent was used for its purpose. The inventors have discovered how to achieve these goals and have come up with the present invention.

That is, the present invention provides a stripping treatment agent comprising a reaction product of Ken-based polyvinyl acetate and a long-chain alkyl aldehyde.

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 the resulting reaction product will vary. growing.

Furthermore, the Ken-based polyvinyl acetate preferably has an average degree of polymerization of 100 to aooo. 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.

Examples of the long-chain alkyl aldehyde used in the present invention and represented by the general formula R-CHO (R is an alkyl group) include hexadecyl aldehyde, heptadecyl aldehyde, octadecyl aldehyde, nonadecyl aldehyde, eicosyl aldehyde, etc. It is preferable that the representative alkyl group has 16 to 20 carbon atoms.The stripping agent of the present invention is produced by heating a long-chain alkyl aldehyde to a carbon-based polyvinyl acetate in an organic solvent, for example, by heating in the presence of an acid. It consists of a reaction product of Ken-based polyvinyl acetate and a long-chain alkyl aldehyde, which is obtained by a grafting reaction via the aldahyde group. The releasability of the treated layer by this releasable treatment agent, and ultimately the release-adhesion balance, is controlled by the ratio of long-chain alkyl aldehyde introduced into the reaction product.

On the other hand, the introduction ratio of the long-chain alkyl aldehyde is determined by the degree of saponification of the polyvinyl acetate and the blending ratio of the long-chain alkyl aldehyde to the polyvinyl acetate during the reaction. In the present invention, the introduction ratio of the long-chain alkyl aldehyde is determined from the viewpoint of physical properties and performance such as the homogeneity of the target reaction product, the heat resistance of the layer treated with the release treatment agent, and the adhesion to hydrophilic substrates. It is preferable to control the degree of saponification in the polyvinyl acetate, and use the aldehyde in an equivalent amount to the saponification group in the polyvinyl acetate μ to react. 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 substrate is carried out, for example, as an organic solvent solution.

Effects of the Invention According to the polyvinyl acetate-long chain alkyl aldehyde releasable treatment agent of the present invention, it has excellent adhesion (anchoring) even to hydrophilic substrates such as cellophane-based substrates and polyvinyl alcohol-based substrates. Forms a releasable treated layer that has excellent properties (resistance) and does not easily fall off from the base material, has an excellent release-adhesion balance, and has excellent heat resistance so that its releasability does not deteriorate even when stored at high temperatures. be able to.

Examples Example 1 Saponification degree of 88% in a Mitsuro flask equipped with a reflux condenser
, 20 parts of polyvinyl acetate with an average degree of polymerization of 500 (parts by weight,
) and 182 parts of xylene were added and heated to 120°C, and 5 ml of 1/2N hydrochloric acid was added to acidify the system. 121 parts of octadecyl aldehyde was added and reacted for 10 hours to produce the desired product. A releasable treatment agent was obtained.

Examples 2 to 5 100 parts of polyvinyl acetate/l with a degree of saponification of 8896 and an average degree of polymerization of 1700 and 506 parts of octadecyl aldehyde (
Example 2) Polyvinyl acetate A with a degree of saponification of 88% and an average degree of polymerization of 1400
/100 parts and 506 parts of octadecyl aldehyde (same as 3)
% Polyvinyl acetate with saponification degree of 80% and average polymerization degree of SOO 1
00 parts and 474 parts of eicosyl aldeced (4), polyvinyl acetate A with a saponification degree of 38% and an average degree of polymerization of 1400/
A stripping agent was obtained in the same manner as in Example 1, except that 100 parts and 229 parts of eicosylaldehyde (5) were used.

Comparative Example 1.2 Polyvinyl acetate A/with a degree of saponification of 88% and an average degree of polymerization of 500
100 parts of polyvinyl acetate with a degree of saponification of 88% and an average degree of polymerization of 1400 and 530 parts of octadecyl isocyanate (Comparative Example 1). I got it.

Toluene was added to the reaction solution containing the release treatment agent obtained in the evaluation test examples and comparative examples to make a solution with a solid content of 1% by weight, and this was applied to one side of a cellophane film at a coating amount of o, ospz♀. It was dried to obtain a peelable treated film.

Next, a polypropylene adhesive tape (manufactured by Nitto 1!IF Denko Kogyo Co., Ltd., 7L31D) was applied to the treated surface of the obtained film.
were crimped by moving a 2 kq loaf back and forth once, and then a 180 degree beer test was performed on the normal condition or the condition after being left at 70° C. for 24 hours to return to the normal condition, and the peeling force was measured.

On the other hand, by rubbing the treated surface of the film with your fingers,
Check the ability of the treated layer to fall off from the base material, and if there is no falling off, mark it as ○.
, Cases where there was some falling off were evaluated as ×.

The results are shown in the table.

The layer treated with the releasable treatment agent of the present invention in the examples shown in the table is as follows:
It can be seen that the adhesiveness to the substrate, the peel-adhesion balance, and the heat resistance are excellent.

Claims (1)

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