JPH06158555A - Production of releasing sheet - Google Patents

Abstract

PURPOSE:To provide a process for producing a releasing sheet for the production a synthetic leather, having excellent transferability of the surface pattern of a mold to the releasing sheet, free from coating defect and repeatedly usable in the production of a synthetic leather. CONSTITUTION:An inside coating liquid layer 12 curable by electron ray is formed on a substrate. Separately, an outside coating liquid layer 7a curable by electron ray or ultraviolet ray is formed on a forming surface. The outside coating liquid layer is cured by electron or ultraviolet irradiation 6 to form an outside releasing layer 7. The releasing layer 7 is pressed to the inside coating liquid layer 12 and the formed laminate is irradiated with electron ray 14 to cure the inside coating liquid layer and obtain an inside resin layer bonded to the substrate and the outside releasing layer. The obtained laminate is peeled off from the forming surface to obtain a releasing sheet.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a release sheet. More specifically, the present invention relates to a method for producing a release sheet suitable for producing synthetic leather.

[0002]

2. Description of the Related Art A release sheet is used in a process for producing synthetic leather from materials such as polyvinyl chloride and polyurethane by a casting method or the like, and is obtained by laminating a polypropylene film on a paper substrate.
It is known that a base material is coated with a silicone compound, an aminoalkyd resin, a chromium compound or the like and heat-cured. However, these conventional release sheets have drawbacks in any one of surface workability, surface gloss, chemical resistance, heat resistance, reusability, etc. Therefore, they are used properly according to the application.

On the other hand, an electron beam curable coating material is applied onto a sheet-like support, and this coating material layer is pressure-bonded to the molding surface, and either during or after being pressure-bonded to the molding surface, or after peeling from the molding surface. It is known that a release sheet having a surface pattern can be produced by irradiating an electron beam on the resin to cure it and transferring the surface pattern of the molding surface. The release sheet produced by using the electron beam as described above has a solid content of 100%.
In the state of having fluidity, the release layer coating composition of (1) is pressure-bonded onto a molding surface having a pattern, and thereafter, to cure this,
Compared to those applying a surface pattern by mechanical means, it has good transferability of the surface pattern of the molding surface to the release sheet, there are no surface defects such as pits, and further curability depending on the selection of the release layer coating material, Surface tension, flexibility, etc. are relatively easy to control, so mold releasability, chemical resistance in synthetic leather manufacturing process,
It has been considered that the abrasion resistance, the reusability, and the like are improved, and a release sheet which has never been obtained can be obtained.

However, the method described in Japanese Examined Patent Publication No. 63-2780, that is, an electron beam curable coating material is applied onto a paper base material and pressed onto a molding surface, and an electron beam is applied while being pressed onto the molding surface. In the method for producing a release sheet, in which the composition is irradiated with to cure the composition and the surface pattern on the molding surface is transferred,
When crimping the electron beam curable paint on the paper base to the molding surface,
When the paint viscosity is high, air bubbles remain between the paint and the molding surface,
The good transferability of the surface pattern of the molding surface to the release sheet, which should be exhibited by using the electron beam curable paint, is impaired. When the viscosity of the paint is low, air bubbles that exist between the paint and the molding surface penetrate into the paint, and as a result, air bubbles remain in the cured coating film after curing and coating defects occur, or when paint is applied by pressure bonding. Is easy to flow, and uneven coating occurs on the release sheet.

Further, since the electron beam is irradiated from the side of the paper base material opposite to the coated surface, the strength of the paper base material is lowered when the electron beam curable coating is sufficiently cured, and especially the heat and folding endurance is improved. Remarkably deteriorated, it becomes impossible to repeatedly use the release sheet in the synthetic leather manufacturing process, and if cured insufficiently, the releasability required for the release sheet surface during the production of synthetic leather,
The chemical resistance and abrasion resistance are lowered, and further the reusability is remarkably deteriorated. That is, when the electron beam irradiation is performed by this method, the problem that the usability is repeatedly lowered occurs in either the base material of the release sheet or the release layer.

Therefore, in the method of Japanese Patent Laid-Open No. 59-1029, a method of irradiating an electron beam twice, that is, an electron beam curable coating material on a substrate is pressure-bonded to a molding surface, and the first electron beam irradiation is performed. Describes a method of curing the surface pattern so that the surface pattern can be transferred, peeling the surface pattern from the molding surface, and then irradiating the electron beam again to sufficiently cure the electron beam curable coating material. However, even in this method, the paper base material is greatly damaged by the double irradiation of the electron beam, and the strength of the paper base material is lowered, and as a result, the reusability in the synthetic leather manufacturing process is deteriorated.

On the other hand, an electron beam curable coating material on a paper base material is pressure-bonded to a molding surface having a surface pattern to transfer the pattern on the molding surface to a paint layer, which is peeled off from the molding surface and then irradiated with an electron beam. The method of curing by means of this method is also described in JP-B-64-10626. However, in order to transfer the surface pattern of the molding surface to the paint layer and keep this transferred pattern until it is cured by electron beam, the condition is that the paint does not have fluidity, and therefore, from the molding surface. The surface transferability of is not much different from that by mechanical means.

[0008]

SUMMARY OF THE INVENTION The present invention solves the above problems of a release sheet obtained by transferring the surface pattern of the molding surface using a conventional electron beam or ultraviolet curable coating material, An object of the present invention is to provide a method for producing a release sheet, which has excellent transferability of the above surface pattern to a release sheet, has no coating defects, and has good repeatability in the synthetic leather production process.

[0009]

DISCLOSURE OF THE INVENTION The present invention is intended to solve the above-mentioned drawbacks of the prior art, and as a result of intensive studies by the present inventors, electron beam or ultraviolet ray curing on a molding surface having a surface pattern. To form an outer coating liquid layer
By subjecting this to electron beam or ultraviolet irradiation to cure sufficiently, no air bubbles remain between the outer cured coating film and the molding surface and in the coating film, and good transferability without coating defects is realized, Furthermore, by fully curing the sheet-like support without damaging it, it has excellent releasability, chemical resistance, and abrasion resistance required for a release sheet, and therefore has an outer release layer that can be used repeatedly. It succeeded in obtaining a release sheet.

Further, an inner coating liquid layer containing an electron beam curable coating material, which is separately formed on a support, as a main component is pressure-bonded to the outer release layer on the molding surface to form a multi-layer body thus formed. Minimize damage to the sheet-like support by electron beams by applying the electron beam necessary for curing the inner coating liquid layer and bonding the resulting inner resin layer to the outer release layer and the support. Thus, the present invention has been completed by succeeding in obtaining a release sheet which has good reusability and fully exhibits the characteristics of an electron beam or ultraviolet ray curable coating.

The release sheet manufacturing method according to the present invention comprises a sheet-like support, an inner resin layer formed on the sheet-like support, and an outer release layer formed on the inner coating layer. When manufacturing a release sheet consisting of, a coating solution containing an unsaturated compound which is hardened by electron beam irradiation as a main component is applied on one surface of a sheet-like support to form an inner coating solution layer, and a separate surface pattern is formed. On the molding surface having, an outer coating solution layer is formed by applying a coating solution containing an unsaturated compound as a main component that is cured by electron beam or ultraviolet irradiation, and an electron beam is applied to the outer coating solution layer on the molding surface. Alternatively, by irradiating ultraviolet rays, to cure it to form an outer release layer, on the outer release layer on the molding surface, superimpose the inner coating liquid layer on the support,
The multilayer body thus formed is irradiated with an electron beam and irradiated to cure the inner coating liquid layer, and the inner resin layer formed thereby is bonded to the support and the outer release layer to form a laminate. And peeling the laminate from the molding surface.

The method of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a coating solution coating and curing facility 1 using a metal drum as a molding surface. The electron beam curable coating material 3 for the outer release layer is formed by using the coater 4 of the container 2.
It is applied on the molding surface of the metal drum 5 to form the outer coating liquid layer 7a, and then the outer coating liquid layer 7a is irradiated with an electron beam from the first electron beam irradiation device 6 to cure the outer coating liquid layer 7a. The release layer 7 is formed. On the other hand, the electron beam curable coating material 9 for the inner resin layer in the container 8 is applied on the sheet-shaped support 11 using the coater 10 to form the inner coating liquid layer 12. The support 11 and the inner coating liquid layer 12 are the guide roll 1
3, the inner coating liquid layer 12 is pressure-bonded onto the outer release layer 7 on the metal drum molding surface 5, and the multilayer body thus formed is irradiated with an electron beam from the second electron beam irradiation device 14, The inner coating liquid layer is cured to form an inner resin layer, and the inner resin layer is joined to the support 11 and the outer release layer 7 to form a laminate 16, and the guide roll 15 forms the laminate 16 into a metal drum. A release sheet can be obtained by peeling from the surface 5. To form the outer coating liquid layer,
When an ultraviolet curable coating material is used, an ultraviolet irradiation device is installed instead of the first electron beam irradiation device 6.

FIG. 2 shows a coating liquid coating and curing facility 1 when the film 17 is used as a molding surface. In this case, the irradiation from the second electron beam irradiation device 14 may be performed through the molding surface film 17 as shown in FIG. 2, or the sheet-shaped support on the side opposite to the molding surface film may be provided. You may give from the back. However, in the former case, the damage to the sheet-shaped support 11 can be further suppressed, and thus it is more preferable as the method for producing the release sheet. Although this molding film can be repeatedly used after being wound up, it may be formed into an endless belt. The molding film is not necessarily a plastic film, and a belt-shaped metal film may be used.

As the unsaturated organic compound which is hardened by an electron beam and is used for forming each of the inner coating liquid layer and the outer coating liquid layer of the present invention, an acrylate having one or more ethylenically unsaturated bonds or Methacrylate-based monomers or oligomers can be used, but are not limited to these. Among such electron beam curable monomers, for example, as a monomer having one ethylenically unsaturated bond, N-vinylpyrrolidone, acrylonitrile or a derivative thereof, styrene or a derivative thereof, an amide group-containing monomer such as acrylamide, lauryl ( Acrylate of fatty acid such as (meth) acrylate, or methacrylate, benzyl acrylate, 2-ethylhexyl acrylate,
2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, tetrahydrofurfuryl acrylate, phenoxyethyl acrylate, nonylphenoxyethyl acrylate, ε-caprolactone adduct acrylate, butoxyethyl (meth) acrylate, 2-hydroxy -3-phenoxypropyl acrylate, cyclohexyl (meth) acrylate, N, N-dimethylamino (meth) acrylate,
N, N-dimethylaminoethyl (meth) acrylate,
An acrylate such as 3-phenoxypropyl acrylate and 2-methoxyethyl (meth) acrylate or a methacrylate is used.

Examples of the monomer having two or more ethylenically unsaturated bonds include hexanediol diacrylate, nonanediol diacrylate, neopentyl glycol diacrylate, diethylene glycol diacrylate, tripropylene glycol diacrylate and tetraethylene glycol diacrylate. , Tricyclodecane dimethylol diacrylate, trimethylol propane triacrylate, ditrimethylol propane tetraacrylate, ethylene oxide modified bisphenol A diacrylate, and the like.
These monomers having one or more ethylenically unsaturated bonds may be used alone or as a mixture of two or more, if necessary.

The above ethylenically unsaturated monomer composition is blended with at least one acrylate or methacrylate oligomer having two or more ethylenically unsaturated bonds in the molecule, such as urethane acrylate oligomer or butadiene modified acrylate oligomer. The thing is
It is effective from the viewpoint of adjusting the viscosity of the obtained paint and the flexibility of the obtained cured film.

As a performance required for the inner coating liquid layer or the inner resin layer, the outer release layer cured on the molding surface can be smoothly peeled off from the molding surface and completely adhered to the sheet-like support. What is possible, and after press-bonding the outer release layer and the inner coating liquid layer, when being irradiated with an electron beam through the sheet-shaped support, it can be cured with a dose that minimizes damage to the sheet-shaped support, And so on. Therefore, for example, a compound containing two or more ethylenically unsaturated bonds and having good adhesiveness and curability as a main component is preferable.

As described above, it is possible to use an ultraviolet curable coating material for the outer coating liquid layer and to use curing by ultraviolet irradiation. In this case, the outer coating liquid layer is used together with the unsaturated organic compound in a predetermined amount. It is necessary to include a photoinitiator and the like. As the molding surface on which the outer coating liquid layer is applied, it is possible to use a metal drum, a metal roll, a metal film, a plastic film or the like having high dimensional stability as described above. A surface pattern such as embossing may be applied to the molding surface to be pressure-bonded to, or it may have a mirror gloss. In order to facilitate peeling from the molding surface, higher fatty acid-based mold release agents such as calcium stearate, zinc stearate, etc. on the molding surface, if necessary,
Polyethylene type release agent such as polyethylene emulsion,
A release agent such as wax or silicone may be applied.

The outer release layer obtained by curing the outer coating liquid layer is surface curable from the viewpoints of releasability, chemical resistance, abrasion resistance, and reusability required for manufacturing synthetic leather. Is good and the surface tension is 35 d
It is preferably yn / cm or less. Therefore, as the coating material used for the outer coating liquid layer, a mixture containing as a main component a monomer and / or an oligomer having two or more ethylenically unsaturated bonds, for example, a polyethylene-modified or polybutanediene-modified urethane acrylate oligomer, A compound containing, as a main component, an acrylate monomer having a long-chain alkyl group is preferable. In addition, soluble or reactive or non-reactive silicone may be added to the outer release layer coating material for the purpose of controlling the surface tension within the range where the surface curability is not impaired. If the amount of the additive compounded is too large, the curability of the obtained coating liquid layer will decrease, which is not preferable.

When an ultraviolet-curable coating material is used in the outer coating liquid layer, the photoinitiator is added to 100 parts by weight of an unsaturated organic compound having one or more ethylenically unsaturated bonds.
Acetophenone, benzophenone, benzoin alkyl ether, azobisisobutyl nitrile etc. 0.1-5
Mix in a proportion of about 1 part.

As described above, in the method of the present invention, the inner coating liquid layer and the outer coating liquid layer are formed of a coating material containing an unsaturated organic compound as a main component, and if necessary, required for the release sheet. It is possible to mix auxiliaries such as colored dyes, colored pigments, lubricants, antistatic agents, etc. within a range that does not impair the performance of
Titanium dioxide, zinc oxide, kaolin clay, talc, aluminum hydroxide, magnesium oxide, diatomaceous earth, satin white, barium sulfate, basic calcium carbonate,
It is also possible to add a white pigment such as silicon dioxide or aluminum oxide.

In the method of the present invention, the coating composition for the inner coating liquid layer is coated on a support, and the inner coating liquid layer is pressure-bonded onto the outer release layer cured on the molding surface. Irradiate electron beam to cure instantly. In this case, the coating amount of the inner coating liquid layer is preferably controlled in the range of 1 to 30 g / m ² , more preferably 5 to 20 g.
/ M ² . If it is less than 1 g / m ² , it may be difficult to firmly adhere the cured outer release layer to the sheet-like support, and the resulting laminate may be smoothly separated from the molding surface. If it is more than 30 g / m ^2, it may be difficult to obtain a sufficiently cured inner resin layer by electron beam irradiation with a low dose.

The separately prepared coating material for the outer coating liquid layer is applied to the molding surface before pressure bonding with the inner coating liquid layer on the support, and is irradiated with electron rays or ultraviolet rays to be cured. . The coating amount in this case depends on the depth and shape of the surface pattern on the molding surface, but the releasability required for the release sheet,
It is important not to affect chemical resistance, heat resistance, and reusability, and it is preferably 1.0 g / m ² or more, more preferably 2.0 g / m ² or more.

As the coating method for forming the inner coating liquid layer and the outer coating liquid layer, all the usual coating methods using a roll coater, a Mayer bar, a slit die coater, a curtain coater, etc. can be used. In particular, when the surface of the metal drum is used as the molding surface, a roll coating method using a rubber roll, an offset gravure method or the like is preferable from the viewpoint of not damaging the molding surface.

The electron beam accelerator used for electron beam irradiation is not particularly limited in its system, and for example, an electron beam irradiation device of scanning system, electron curtain system or the like can be used. Among them, the electron curtain type, which is relatively inexpensive and can obtain a large output, is effectively used. Accelerating voltage during electron beam irradiation is 100
It is preferably KV or more, and the absorbed dose is preferably as small as possible from the viewpoint of minimizing damage to the substrate.

As an ultraviolet irradiation device used for ultraviolet irradiation, a low pressure emitting a light ray having a wavelength of 180 to 400 nm,
A light source such as a high pressure mercury lamp or a short arc discharge lamp can be applied.

As the sheet-like support constituting the release sheet, paper, synthetic paper, synthetic resin film, or a laminated sheet combining them can be used.
Further, a surface-treated support may be used for the purpose of improving the adhesiveness and the barrier property. The thickness of such a support is not particularly limited, but it is preferably 20 to 250 μm from the viewpoint of strength, workability, electron beam permeability, and the basis weight is 20 to 250 g / m ² . Preferably there is.

[0028]

The present invention will be described in detail with reference to the following examples, but the scope of the present invention is not limited to these examples. In each example, "part" means "part by weight" unless otherwise specified.

Example 1 A coating composition for the outer coating liquid layer (composition 1) having the following composition was prepared by uniformly dispersing it in a Cowles mixer. On the surface of an embossed chrome-plated metal plate used as a molding surface, the above coating composition (composition 1) was applied using a Meyer bar so that the coating amount was 7.0 g / m ² . This coating layer is irradiated with an electron beam by an electron curtain electron beam accelerator (manufactured by ESI) under the conditions of an acceleration voltage of 170 KV and an absorbed dose of 4.0 Mrad on the surface of the outer coating liquid layer, and the coating liquid layer is cured to the outside. A release layer was formed.

Composition 1 (for forming outer release layer) Component amount Nonanediol diacrylate 70 parts Hydrogenated butadiene modified acrylate oligomer (Nippon Soda, trademark: TEAI1000) 30 parts

A separately prepared coating composition for inner coating liquid layer (composition 2) having the following composition was prepared by mixing and dispersing with a Cowles mixer. The above coating composition (composition 2) was applied onto cast-coated paper (127.9 g / m ² , manufactured by Oji Paper Co., Ltd., trademark: OK enamel coat) at a coating amount of 10 g /
m ² and then the inner coating liquid layer is pressure-bonded onto the outer release layer cured on the above-mentioned metal plate molding surface,
From the back surface of the cast coated paper support, an acceleration voltage of 200 KV and an absorbed dose of 1.5 Mrad under the support were applied to the obtained multilayer body.
The inner coating liquid layer is cured by irradiating an electron beam under the conditions of 1., the inner resin layer thus formed is bonded to the outer release layer and the support to form a laminated body, and the laminated body is Then, it was peeled off to obtain a release sheet.

Composition 2 (for forming inner resin layer) Component amount Tetraethylene glycol diacrylate 45 parts Urethane acrylate oligomer (trade name: Beamset 551B, manufactured by Arakawa Chemical Co., Ltd.) 55 parts

(Example of use) A polyvinyl chloride sol having the following composition was coated on the obtained embossed release sheet using an applicator bar so that the solid coating amount was 30 g / m ^2. The foamed polyvinyl chloride sheet layer was molded by heating and curing at -3 ° C. for 3 minutes, and this was peeled from the release sheet to obtain a foamed polyvinyl chloride sheet.

Composition 3 (for forming foamed polyvinyl chloride sheet) Component amount Polyvinyl chloride 100 parts (Nippon Zeon Co., Ltd., trademark: Zeon 121) Dioctyl phthalate 50 parts Foaming agent (azodicarbonamide) 5 parts Stabilizer Part 3 (Katsuda Kako Co., Ltd., trademark: BZ-100CJ)

Example 2 A coating material for the outer release layer (composition 4) having the following composition was prepared by uniformly dispersing it in a Cowles mixer. On the surface of an embossed aluminum plate used as a molding surface, the above-mentioned coating composition (Composition 4) is applied using a Mayer bar.
Was applied to give a coating amount of 15 g / m ² , and the coating liquid layer was applied with an accelerating voltage of 1 by the same electron beam accelerator as in Example 1.
70KV, absorbed dose 3.5Mrad on the surface of outer coating liquid layer
The coating solution layer was cured by irradiating with an electron beam under the conditions described above to form an outer release layer.

Composition 4 (for forming outer release layer) Component amount Bifunctional acrylate monomer 25 parts (Toagosei, trade name: M233) Nonanediol diacrylate 30 parts Hydrogenated butadiene modified acrylate oligomer 45 parts (Nippon Soda, Trademark: TEAI1000)

An inner resin layer coating composition (composition 5) having the following composition prepared separately was mixed and dispersed in a Cowles mixer to prepare a mixture. On the coated paper (127.9 g / m ² , manufactured by Oji Paper Co., Ltd., trademark: OK coat), the above coating composition (composition 5) was applied using an applicator bar so that the coating amount was 15 g / m ² The coating liquid layer is pressure-bonded to the outer release layer on the above-mentioned aluminum plate molding surface to form a multilayer body,
An inner resin layer is formed by simultaneously irradiating an electron beam from the back surface of the coated paper support with an accelerating voltage of 200 KV and an absorbed dose of 1.5 Mrad under the support to cure the inner coating liquid layer, and at the same time, to form the inner resin. The layer was joined to the support and the outer release layer to form a laminate, and then the laminate was peeled from the molding surface to obtain a release sheet.

Composition 5 (for forming inner resin layer) Component amount Tetrapropylene glycol diacrylate 50 parts Urethane acrylate oligomer 50 parts (Arakawa Chemical Co., Ltd., trademark: BS505B)

(Example of use) Example 1 was placed on this release sheet.
A foamed polyvinyl chloride sheet was molded in the same manner as in 1. and peeled from the release sheet to obtain a foamed polyvinyl chloride sheet.

Example 3 An outer release layer coating composition (composition 6) having the following composition was prepared by uniformly dispersing with a Cowles mixer. The above coating composition (composition 6) is applied to the surface of an embossed and chrome-plated metal plate used as a forming surface by using a Meyer bar so that the coating amount is 7.0 g / m ^2. Then, the outer coating liquid layer was irradiated with ultraviolet rays by an ultraviolet irradiation device (manufactured by Eye Graphic Co.) to cure the outer coating liquid layer to form an outer release layer. Others are Example 1
A release sheet was prepared in the same manner as in.

Composition 6 (for forming outer release layer) Component amount Nonanediol diacrylate 70 parts Hydrogenated butadiene modified acrylate oligomer 30 parts (Nippon Soda, trademark: TEAI1000) Benzoin ethyl ether 3 parts

A foamed polyvinyl chloride sheet was molded on this release sheet in the same manner as in Example 1 and peeled from the release sheet to obtain a foamed polyvinyl chloride sheet.

Comparative Example 1 A release sheet was prepared in the same manner as in Example 1. However, an embossed chrome-plated metal plate which is used as a molding surface by coating the outer release layer coating composition (composition 1) on the surface of a cast-coated paper support without providing an inner resin layer After the outer coating liquid layer was pressure-bonded onto the molding surface of the, the outer release layer was cured by irradiating with an electron beam from the back of the cast coated paper support under the conditions of an acceleration voltage of 200 KV and an absorbed dose of 2 Mrad under the support. Was formed, and the obtained laminate was peeled from the molding surface to prepare a release sheet. Further, in the same manner as in Example 1, a foamed polyvinyl chloride sheet layer was molded on this release sheet, and the release sheet was peeled off to obtain a foamed polyvinyl chloride sheet.

Comparative Example 2 A release sheet was prepared in the same manner as in Example 1. However, without providing the inner resin layer, the outer coating liquid layer is formed on the surface of the cast coated paper support, and the outer coating liquid layer is formed on the metal plate molding surface which is embossed and used as a molding surface and which is plated with chrome. After press-bonding, an outer release layer is formed by irradiating an electron beam from the back surface of the cast coated paper support with an accelerating voltage of 200 KV and an absorbed dose of 4 Mrad under the support to cure it, thereby forming an outer release layer. The body was peeled from the molding surface to prepare a release sheet. Further, in the same manner as in Example 1, a foamed polyvinyl chloride sheet layer was molded on the release sheet, and the release sheet was peeled off to obtain a foamed polyvinyl chloride sheet.

Comparative Example 3 A release sheet was prepared in the same manner as in Example 1. However, without providing the inner resin layer, the outer coating liquid layer is applied to the surface of the cast-coated paper support, and the outer coating liquid layer is used as a molding surface. An embossed chrome-plated metal plate is used. After press-bonding to the surface of the cast coated paper, electron beam is irradiated from the back surface of the cast coated paper support under the conditions of an acceleration voltage of 200 KV and an absorbed dose of 1.5 Mrad under the support to partially cure it, An accelerating voltage of 175 was applied to the outer coating liquid layer which was peeled off and then partially cured, from the outer coating liquid layer side.
An electron beam was irradiated under the conditions of KV and an absorbed dose of 2.0 Mrad on the surface of the outer coating liquid layer, and this was completely cured to form an outer release layer to prepare a release sheet. Further, in the same manner as in Example 1, a foamed polyvinyl chloride sheet layer was molded on the release sheet, and this was peeled from the release sheet to obtain a foamed polyvinyl chloride sheet.

Comparative Example 4 A release sheet was prepared in the same manner as in Example 2. However, after coating the outer coating liquid layer on the surface of the coated paper support without providing the inner resin layer and using this outer coating liquid layer as the molding surface, after pressure bonding to the surface of the embossed aluminum plate , 200K acceleration voltage from the back of coated paper support
V, an electron beam was applied under the condition of an absorbed dose of 3.5 Mrad under the support to cure the electron beam to form an outer release layer, which was peeled from the molding surface to prepare a release sheet. Further, in the same manner as in Example 2, a foamed polyvinyl chloride sheet layer was molded on the release sheet, and this was peeled from the release sheet to obtain a foamed polyvinyl chloride sheet.

Performance Test The release sheet and the expanded polyvinyl chloride sheet were measured for surface pattern transferability, coating property, peeling strength, folding endurance, and reusability by the following methods. (1) Transferability of Surface Pattern Using an optical microscope, sensory evaluation was performed in the following three stages depending on whether the embossed pattern was completely transferred to the surface of the release sheet. (○: good, △: normal, ×: bad)

(2) Coating Property The number of coating defects such as pits on the release sheet was counted using an optical microscope, and sensory evaluation was performed in three stages (○: good, Δ: normal,
X: defective). (3) Peeling force The peeling force when peeling the expanded polyvinyl chloride sheet from the release sheet was measured according to JIS-K-6555. (4) Folding endurance The release sheet after molding a polyvinyl chloride film once was measured according to JIS-P-8115.

(5) Repeatability The procedure of coating polyvinyl chloride sol on a release sheet, heating and curing it, molding the film and releasing the mold was repeated 4 times, and then the 5th time, the foamed polychlorinated foam was released from the release sheet. The peeling force at the time of peeling the vinyl film, the folding endurance of the release sheet, the image clarity of the release sheet and the foamed polyvinyl chloride sheet, and the surface shape were measured and observed, and a sensory evaluation was performed on the following three levels. (○: good, △: normal, ×: bad)

The test results are shown in Table 1.

[Table 1]

[0051]

As is clear from Table 1, the release sheet produced by the method of the present invention is excellent in transferability of the surface pattern on the molding surface to the release sheet and has no coating defects. It has good reusability in the synthetic leather production process and is extremely useful in practice in the production of synthetic leather.

[Brief description of drawings]

FIG. 1 is a process explanatory view of a method of the present invention when a release sheet is formed by using a metal drum as a molding surface.

FIG. 2 is a process explanatory view of the method of the present invention when a plastic film is used as a forming surface.

[Explanation of symbols]

 1 ... Coating liquid coating and curing equipment 2 ... Paint container 3 ... Coating material for outer release layer 4 ... Coater 5 ... Molding surface drum 6 ... First electron beam irradiation device 7a ... Outer coating liquid layer (before curing) 7 ... Outer release Layer 8 ... Paint container 9 ... Inner resin layer paint 10 ... Coater 11 ... Sheet support 12 ... Inner coating liquid layer 13 ... Guide roll 14 ... Second electron beam irradiation device 15 ... Guide roll 16 ... Support / inner resin Layer / outer release layer laminate 17 ... Molding film

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Claims (1)

[Claims] 1. When manufacturing a release sheet comprising a sheet-shaped support, an inner resin layer formed on the sheet-shaped support, and an outer release layer formed on the inner coating layer, On one surface of the sheet-shaped support, a coating liquid containing an unsaturated compound as a main component that is cured by electron beam irradiation is applied to form an inner coating liquid layer, and separately on a molding surface having a surface pattern, an electron beam, Alternatively, an outer coating liquid layer is formed by applying a coating liquid containing an unsaturated compound as a main component that is cured by ultraviolet irradiation, and the outer coating liquid layer on the molding surface is irradiated with an electron beam or ultraviolet rays and cured. Then, an outer release layer is formed, and an inner coating liquid layer on the support is superposed on the outer release layer on the molding surface, and an electron beam and irradiation are applied to the multilayer body formed thereby. , While curing the inner coating liquid layer, The inner resin layer formed Te, support, and joined together to form a laminate to the outer release layer is peeled off the laminate from the molding surface includes method for producing a release sheet.