JPS61127776A - Release sheet - Google Patents

Abstract

PURPOSE:The titled sheet, obtained by forming a release agent layer through an undercoating layer consisting essentially of a crosslinking reaction product of an epoxide with an alkylated melamine, and having improved adhesivity of the release agent and heat resistance. CONSTITUTION:A release sheet obtained by applying (A) a coating solution containing a bisphenol based epoxide having 300-3,000mol.wt., polyglycol based epoxide and butylated melamine in combination onto (B) a sheetlike support, e.g. a laminate of a paper base material on a metal foil, drying and curing the resultant coat, and forming a release agent layer through the resultant undercoating layer.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a release sheet comprising a sheet-like support and a release agent layer provided on at least one side of the support via an undercoat layer.

(Prior art) Currently, a wide variety of release sheets are used for adhesive products such as adhesive tapes and Lyle, as well as for manufacturing processes of synthetic leather, molded products, etc., such as polyvinyl chloride synthetic leather and carbon fiber prepreg. . The main performance required of a release sheet is that in the case of an adhesive product, it must protect the adhesive surface of the adhesive sheet and have good releasability during use.
In addition, when used in manufacturing processes, it has good peelability and good workability.
The sheet should have strength and heat resistance suitable for various processes. Such a release sheet has a release agent layer provided on at least one side of a sheet-like support via an undercoat layer.

The sheet-like support may be an inert polymer film, metal foil, etc. Among these sheet-like supports, it is difficult to obtain arbitrary releasability with a polymer film having an inactive surface, and its use when used alone is limited. Moreover,
Polymer films and metal foils do not have any undercoating agent that has good adhesion with the release agent, so corona discharge treatment is mainly used to improve adhesion, but other than polyethylene film, the adhesion is sufficiently satisfactory. Sex is not obtained.

In addition, release sheets are repeatedly exposed to various kinds of heat during processing and use, and in this case, the undercoating agent must have heat resistance that does not cause any change in the strength of the sheet or its adhesion to the release agent.

On the other hand, paper-based release sheets are currently used in many fields;
) Those coated with clay-based pigments, (2) those coated with a water-soluble polymer such as polyvinyl alcohol, and (3) those coated with extrusion polyethylene are widely used. However, (1) has poor adhesion with the release agent, and (2)
The film becomes soft due to moisture absorption, and the heat resistance of (3) is poor.

Therefore, the undercoat layer used in a paper-based release sheet cannot be applied to a polymer film or metal foil release sheet used in applications requiring release agent adhesion and heat resistance.

As mentioned above, conventional release sheets have various drawbacks, but an undercoat that satisfies all of the performances required for a wide variety of adhesive products and for release sheets through advanced processing in the manufacturing process. There is no release sheet with a layer, and such a release sheet is strongly desired.

(Problems to be Solved by the Invention) An object of the present invention is to improve the above-mentioned drawbacks and to provide a base material for a release sheet that has excellent release agent adhesion and heat resistance.

(Means for Solving the Problems) In the release sheet of the present invention, the undercoat layer formed on at least one side of the sheet-like support is formed mainly of a crosslinking reaction product of epoxide and alkylated melamine. It is characterized by being something.

That is, by applying a coating solution of a mixture of epoxide and alkylated melamine to one or both sides of a sheet-like support and drying to form a release agent layer, a release sheet with excellent release agent adhesion and heat resistance can be obtained. can do.

As the sheet-like support constituting the release sheet of the present invention, polymer films and metal foils are suitable. These may be used alone or in the form of a stack of these. Further, it may be used in the form of a laminate with a porous base material such as paper or nonwoven fabric.

Examples of polymer films include polyolefin films such as polyethylene, polypropylene, polypuden, polymethylpentene, and methyl pentene copolymers with a thickness of 3 to 150 μm, polyethylene terephthalate films, polyvinyl chloride films, polyvinylidene chloride films, and fluororesin films. film, polyhexamethylene adipamide film, and the like.

As the metal foil, copper foil, aluminum foil, iron foil, tin foil, etc. with a thickness of 3 to 100 μm are used.

The epoxide used in the present invention includes glycidyl type epoxide, bispheno-ρ type, novolac type, alkylphenol type, resorcin type, polyglycol type, and the like.

The alkyl group of the alkylated melamine includes methyl group, ethyl group, propyl group, butyl group, and the like.

A preferred combination of monomers has a molecular weight of 300 to 3.000.
It is a combination of bisphenol-based epoxide, polyglycol-based epoxide, and butylated melamine.

When a coating solution of a mixture of epoxide and alkylated melamine is applied onto a sheet-like support, dried and cured, a film with good release agent adhesion and heat resistance is formed.

In addition, for the purpose of improving the suitability for processing into a sheet-like support and other properties of the crosslinking reaction product of epoxide and alkylated melamine, as long as the purpose of the present invention is not impaired,
Addition of a diluting solvent, curing accelerator, etc. is optional.

To form an undercoat layer with a crosslinking reaction product of epoxide and alkylated melamine on a sheet-like support, apply a coating solution of a mixture of epoxide and alkylated melamine using a roll coater or the like according to a conventional method. Then dry and harden. The release agent used is not particularly limited, and any known release agent such as silicone resins and non-silicone resins such as long-chain alkyl acrylate polymer resins can be used. Further, the formation of the release agent layer can also be performed according to a conventional method.

The release sheet according to the present invention has excellent release agent adhesion and heat resistance.

(Example) The details will be explained in the following example, but the present invention is not limited thereto in any way.

Example: A polypropylene film (thickness 5
Using a roll coater, a coating solution of a mixture of epoxide and butylated melamine (hereinafter referred to as epoxide mixture) (trade name 5F-410J, manufactured by Dainippon Ink and Chemicals) was applied onto the support using III/rrL (solid content) was coated at 1501:' and dried for 30 seconds to cure.Furthermore, a silicone release agent coating solution diluted with toluene (concentration: 5% by weight) was coated on top of the coating at 130C. So 3
It was dried for 0 seconds and cured to obtain a release sheet.

The release sheet thus obtained was measured for adhesion to a substrate, adhesion to a release agent, heat resistance, and moisture resistance. The adhesion to the substrate, heat resistance, and moisture resistance were measured on the sample before forming the release agent layer, and the adhesion to the release agent was measured by performing the following operations after forming the release agent layer.

(1.) Adhesion to substrate After a cellophane tape for office use was sufficiently pressed onto the film of the undercoating agent, the cellophane tape was peeled off and the state of the film of the undercoating agent was visually observed.

○ (Good)〉Δ〉×(Unacceptable) ○: No change in coating Δ: Slight adhesion to the tape ×: Much adhesion to the tape (2) Adhesion to release agent Apply toluene on the release agent coated surface and remove silicone. The state of the release agent coming off was visually observed.

○(Good)〉Δ〉×(Not good) ○: No falling off.

Δ: Slightly falling off x 2 A lot of falling off (3) Heat resistance The sample was left in a hot air dryer at 150C for 1 minute and the condition of the undercoat film was visually observed.

○ (Good)〉Δ〉× (Unacceptable) ○: No change Δ: Slight melting or discoloration ×: Melting, discoloration, or deterioration After a cellophane tape for office use was sufficiently pressed onto the film, the tape was peeled off and the condition of the primer film was visually observed.

○(Good)〉Δ〉×(Unsatisfactory) O: No change in film Δ: Slight adhesion to tape ×: A lot of adhesion to tape The measurement results are shown in Table 1. Adhesion to substrate , adhesion to release agents, heat resistance, and heat-humidity were all good.

Comparative Example 1-3 The 50μ thick polypropylene film of Example 1 was used as a support, and (1) pigment coating liquid (clay/5BR-
Latex weight ratio = 100/20. concentration 48%),
(2) Coating polyvinyl alcohol and <S>Z-lyethylene, respectively, and performing the same operation as in Example 1 for Kugai,
Prepare comparative sample 1-3.

Regarding these samples, various properties were measured in the same manner as in Example 1, and the results are shown in Table 4.

As is clear from Table 1, appropriate results were not obtained for the samples of Comparative Examples 1-3 compared to the release sheet of Example 1.

Table 1 Example 2 An aluminum foil with a thickness of 30μ was used as a support, and an epoxy resin mixture (trade name 1'-81'
-410J: manufactured by Dainippon Ink & Chemicals Co., Ltd.) was applied with a roll coater to 1117 m2 (solid content).
It was dried and cured at 50C for 30 seconds. Furthermore, a silicone release agent coating solution diluted with toluene (concentration: 5% by weight) was applied and dried and cured at 130C for 130 seconds to obtain a release sheet.

Regarding this release sheet, various properties were measured in the same manner as in Example 1. The results are shown in Table 2. Adhesion to substrates, adhesion to release agents, heat resistance, and moisture resistance were all good.

Comparative Example 4-6 Using the 30μ thick aluminum foil of Example 2 as a support,
On top of that, (1) pigment coating liquid (clay/5BR-latex weight ratio = 100/20. concentration 48es), (2) polyvinyl alcohol, and (3) polyethylene were respectively coated. Comparative sample 4-6 was prepared by performing the same operation as in 2.

Regarding these samples, various properties were measured in the same manner as in Example 2, and the results are shown in Table 2.

Compared to the release sheet of Example 2, appropriate results were not obtained in each of the comparative examples.

Table 2 Example 3 A laminated base material (hereinafter referred to as A! foil laminated paper) of aluminum foil with a thickness of 10 μm and high-quality paper weighing 6417 m2 was used, and on the l foil side of this base material. Epoxide (product name "5"
F-410J: manufactured by Dainippon Ink & Chemicals Co., Ltd.) coating liquid was applied with a roll coater at 11/rrt" (solid content),
It was dried and cured at 150G for 30 seconds. Furthermore, a silicone release agent coating solution diluted with toluene (concentration: 5% by weight) was applied and dried and cured at 130C for 130 seconds to obtain a release sheet.

Regarding this release sheet, various properties were measured in the same manner as in Example 1. The results are shown in Table 3. Adhesion to substrates, adhesion to release agents, heat resistance, and moisture resistance were all good.

Comparative Example 7-9 A of Example 3! Using foil laminated paper as a support, K(1)
Pigment coating liquid (clay/5BR-latex weight ratio = 1
00/20. Concentration 481 (2) Polyvinyl Flu: 2-
(3) Comparative samples 7-9 were prepared in the same manner as in Example 3, except that polyethylene (PE) was applied.

Regarding these samples, various properties were measured in the same manner as in Example 3, and the results are shown in Table 3.

In comparison with the release sheet of Example 3, appropriate results were not obtained in each of the comparative examples.

Table 3 (Effects of the invention) As is clear from Table 1-3,
The release sheet of the present invention has particularly excellent release agent adhesion and heat resistance.

Therefore, the release sheet of the present invention is extremely useful for adhesive products such as adhesive tapes and labels, and process release paper used in the manufacturing process of polyvinyl synthetic leather, carbon fiber prepreg, and the like.

Claims (1)

[Scope of Claims] 1. A release sheet comprising a release agent layer provided on at least one side of a sheet-like support via an undercoat layer, wherein the undercoat layer is formed mainly of a crosslinking reaction product of epoxide and alkylated melamine. A release sheet characterized by being 2. The release sheet according to claim 1, wherein the sheet-like support is a laminate of a paper base material and a metal foil.