JPS61127779A - Release sheet - Google Patents

Abstract

PURPOSE:The titled sheet, obtained by forming an undercoating layer formed from mainly a crosslinking reaction product of an epoxide with a polyvinylphenol based resin, and having improved adhesivity of release agents, heat resistance, etc. CONSTITUTION:A release sheet obtained by forming an undercoating layer consisting essentially of a crosslinking reaction product of (A) an epoxide, e.g., bisphenol based epoxide, with (B) a polyvinylphenol, e.g., poly-p-vinylphenol, on a least one side of a sheetlike support, e.g., a laminate of a paper base material on a metal foil, and forming a release agent layer through the above- mentioned undercoating layer. Preferably, the compounding ratio of the component (B) is as follows; 0.5-5 hydroxyl equivalent component (B) based on one epoxy equivalent component (A).

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 through nine layers of undercoat.

(Prior art) Currently, a wide variety of release sheets are used for adhesive products such as adhesive tapes and labels, as well as for manufacturing processes for synthetic leather, molded products, etc.1, such as polyvinyl chloride synthetic leather and carbon fiber prepreg. There is. The performance required of a release sheet here is that in the case of an adhesive product, it must protect the adhesive surface of the adhesive sheet and have good peelability during use, and in the case of a manufacturing process, it must have good workability. It must have good peelability, sheet strength suitable for various processes, and heat resistance. Such a release sheet has a release agent layer provided on at least one side of a sheet-like support via an undercoat layer.

Examples of sheet-like supports include inert polymer films, metal foils, and the like. Among these sheet-like supports, it is difficult to obtain desired releasability with a polymer film whose surface is inert, and its use when used alone is limited. Moreover,
Polymer films and metal foils do not have any undercoat 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. has not been obtained.

Furthermore, 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 adhesion between the sheet support and the release agent.

On the other hand, paper-based release sheets are currently used in many fields;
) Those coated with a mainly gray pigment, (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, (2)
3) The film becomes soft due to moisture absorption, and 3) has poor heat resistance.

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 their drawbacks, and it is difficult to satisfy all the performance requirements of a wide variety of adhesive products and advanced processing in the manufacturing process. There is no release sheet with an undercoat 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 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 polyvinylphenol resin. It is characterized by being something.

That is, by coating a coating solution of a mixture of epoxide and polyvinylphenol resin on one or both sides of a sheet support, drying and curing to form a release agent layer, a release agent with excellent adhesion and heat resistance can be obtained. You can get a seat.

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 films of polyolefins such as polyethylene, polypropylene, polybutene, polymethylintene, and methyl atenthene 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 is of the glycidyl type, such as ali, bisphenol, novolac, alkylphenol, resorcinol, or holiclinyl, and has a molecular weight of 3.
00 to 4000. Preferably, the molecular weight is 3
20 to 900 bisphenols.

The polyvinylphenol resin used in the present invention is a polymerizable phenol resin with a linear structure, also known as a hydroxystyrene polymer, and has the following general formula (wherein R represents hydrogen or a halogen atom). )
A hydroxystyrene homopolymer containing at least 65% (mol) of hydroxystyrene units represented by, for example, polyhydroxystyrene, polyhydroxychlorostyrene, or polyhydroxybromostyrene; It is obtained from polymers. This homopolymer or copolymer has an average molecular weight of Looo to 2α000, preferably 4000 to aO00, and a water dispersion equivalent weight of 50 to 50.
0° is preferably 100-250.

In addition, the hydroxystyrene unit can be used as another polymerized unit example, t
C. Styrene, α-methylstyrene, chloromethylstyrene, various vinyl ethers, vinyl ketones, acrolein, acrylonitrile, acrylic acid, acrylic esters, methacrylic esters, acrylamide, N,N-dimethylacrylamide, N- Morfoylacrylamide r1 may be copolymerized with at least one of various diene compounds such as divinyl, noin, isoprene, butadiene, cyclontadiene, and maleic anhydride.

A preferred combination of coating fluids is bisphenol epoxide and poly-P-vinylphenol (1), with the epoxy equivalent of the epoxide being 1 and the hydroxyl equivalent of the poly-P-vinylphenol being 0.1 to 10. Preferably it is 0.5 to 5.

When a coating solution of a mixture of these epoxides and polyvinylphenol resin is applied to a sheet-like support, dried and cured, a film having good release agent, adhesion and heat resistance is formed.

Here, in order to form a crosslinking reaction product film between epoxide and Zerivinylphenol resin, if no catalyst is added, it is necessary to heat cure at 200°C or higher.
Not suitable for processing polymer films. harden 15
When K is carried out quickly at 0°C or lower, it is necessary to add a catalyst. As a catalyst, an inorganic base such as potassium hydroxide or an organic base such as amines can be used, and the solid content of the catalyst is 1 to 1 part by weight, preferably 3 to 101 L, per 100 parts by weight of epoxide solid content. It is necessary to add some amount.

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 polyvinylphenol resin, as long as it does not impair the purpose of the present invention, diluting solvents, curing accelerators, etc. It is optional to add agents and the like.

To form an undercoat layer with a crosslinking reaction product of x4 oxide and polyvinylphenol resin on a sheet-like support, a mixture of epoxide 9 and polyvinylphenol resin is coated according to a conventional method. Roll coater the liquid
It can be applied, dried and cured.

The release agent to be used is not particularly limited, and any known release agent such as silicone resin and non-silicone resin such as long-chain alkyl acrylate polymer resin can be used. Formation can also be carried out according to conventional methods.

(Example) The release sheet according to the present invention has excellent release agent adhesion and heat resistance. This will be explained with reference to the following example.
The present invention is not limited thereby.

Example L A polypropylene film (thickness: 50 μm) was used as a sheet-like support, and a mixture (trade name: "Araldai) 6
071": manufactured by Ciba Co., Ltd., and product name "Regi/M": manufactured by Maruzen Sekiyu Co., Ltd.) using a roll coater. /n? (solid content) was applied, dried at 150°C for 30 seconds, and cured. Furthermore, a silicone release agent coating liquid (@R: 5% by weight) diluted with toluene was applied thereon, and dried and cured at 130° C. for 30 seconds to obtain a release sheet.

Adhesion to the base material of the release sheet obtained in this way,
We carefully measured adhesion to release agents, heat resistance, and moisture resistance. The adhesion to the substrate, heat resistance, and moisture resistance were measured on the sample before the release agent layer was formed, and the adhesion to the release agent was measured after the release agent layer was formed by performing the following operations.

(1) Adhesion to substrate After a cellophane tape for office use was sufficiently pressed onto the film of the undercoat, the cellophane tape '11 was separated and the condition of the film of the undercoat was visually observed.

To O (good)〉 × (unacceptable) O: No change in film, Δ: Slight adhesion to tape ×: Much adhesion to tape (2) Adhesion to release agent Apply toluene on the release agent coated surface, The state of the silicone release agent coming off was visually observed.

O (Good)〉△〉×(Unacceptable) ○: No falling off △: Slightly falling off ×: A lot of falling off (3) Heat resistant sample t1 Leave in a hot air dryer at 150°C for 1 minute and then test.
Visually observe the condition of the agent coating.

O (Good)〉Δ〉×(Unsatisfactory) O: No change △: Slight melting or discoloration After applying office cellophane tape to the coating, peel off the tape to reveal the appearance of the primer coating! Visual observation was made.

O (Good)〉Δ〉×(Unsatisfactory) O: No change in film Δ: Slight adhesion to the tape ×: Measurement results with a lot of adhesion to the tape are shown in the first thorn, and the adhesion to the substrate is poor. , adhesion to release agents, heat resistance, and moisture resistance were all good.

Comparative Example 1-5 The 50μ thick polypropylene film of Example 1 was used as a support, and K(1) epoxide (trade name: Araldite 6071J) coating liquid (21 polyvinylphenol (trade name: Resin MJ) was coated on it. Liquid (3) Pigment coating liquid (clay/5BR-9 tex weight ratio -100/20
Comparative sample 1-5 was prepared in the same manner as in Example 1, except that (4) polyvinyl alcohol and (5) polyethylene were applied.

The results of measuring various properties of these samples are also shown in Table 1. As is clear from Part 1, appropriate results were not obtained compared to the release sheet of Example 1.

Table 1 Example 2 An aluminum foil with a thickness of 30 μm was used as a sheet-like support, and an epoxy fi amount I of epoxide 9 was placed on the support.
A mixture of K and 1 hydroxyl equivalent of poly-P-vinylphenol (trade name: Araldai) 6071J
A coating solution of "Resin M" (trade name: manufactured by Chipa Co., Ltd., and "Resin M" (trade name: manufactured by Maruzen Sekiyu Co., Ltd.) was applied with a roll coater to a solid content of 111/nlc), and was dried and cured at 150'C for 30 seconds. Furthermore, silicone release agent coating solution diluted with toluene (concentration 5% by weight)
) was applied thereon and dried and cured at 130° C. for 30 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 1. Good results were obtained in all aspects of adhesion to substrates, adhesion to release agents, heat resistance, and moisture resistance.9.

Comparison Example 6-10 Using the 30μ thick aluminum foil of Example 2 as a support,
Furthermore, K(1) epoxide (product name: acyldite 6)
071J) Coating fi (211F Rivinylphenol (product name: Resin MJ) Coating liquid (3) Pigment coating liquid (Riv-/5BR-Latex Weight ratio -Zoo/20
, concentration 48%) (4) Poly<nyl alcohol (5) 1 t
Comparative samples 6-10 were prepared in the same manner as in Example 2, except that each sample was coated with triethylene.

The results of measuring various properties of these samples are shown in the second section.
Appropriate results were not obtained in each of the comparative examples compared to the release sheet of Example 2 shown here.

Second Example 3 A laminated base material (hereinafter referred to as AJ foil laminated paper) of aluminum foil with a thickness of 10μ and high-quality paper with a basis weight of 64 I/- was used, and the aluminum foil of this base material was used. A mixture of epoxy equivalent IK of epoxide and hydroxyl equivalent of poly P-vinylphenol 1 on the surface (trade name "Araldai" 6071J: Ciba Exhibition, and trade name "Resin M": manufactured by Maruzen Sekiyu Co., Ltd.) 1117tr of coating liquid with a roll coater
? <Solid content> was applied and dried at 150°C for 30 seconds. Furthermore, silicone release agent coating solution diluted with toluene (fI
It was applied thereon in an amount of 5% by weight and dried and cured at 130° C. for 30 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 the third thorn. We were able to obtain good results in all aspects of adhesion to substrates, adhesion to release agents, heat resistance, and moisture resistance.

Comparative Example 11-15 Ad foil laminated paper of Example 3 was used as a support, and K(1)
Epoxide 4 (product name "Araldite 6071J")
Coating liquid (2) Polyvinylphenol (product name “Regi/
M'') Coating liquid (3) Pigment coating liquid (clay/5BR-latex weight ratio ■ 100/20. Concentration 48 inches) (4)
Comparative samples 11-15 were prepared in the same manner as in Example 3, except that polyvinyl alcohol (5) polyethylene was applied to each case.

Table 3 shows the results of measuring various properties of these samples. Compared to the release sheet of Example 3, appropriate results were not obtained in each of the comparative examples.

Table 3 (Effects of the Invention) As shown in Tables 1-3, the release sheet of the present invention has excellent release agent adhesion and heat resistance.

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

(1 other person)

Claims (1)

[Claims] 1. In a release sheet comprising a release agent layer provided on at least one side of a sheet-like support via an undercoat layer, the undercoat layer is formed mainly of a crosslinking reaction product of epoxide and polyvinylphenol resin. 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.