JP2832739B2 - Release sheet having an uneven surface and method for producing the release sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial applications]

The present invention relates to a release sheet having an uneven surface and a method for producing the release sheet, and particularly as a transfer sheet for producing a synthetic leather made of polyurethane, polyvinyl chloride, or the like. Provided are a release sheet that can be suitably used and a method for producing the release sheet.

[Prior art]

In a method of obtaining a synthetic leather made of polyurethane or polyvinyl chloride by a casting method, a resin liquid of polyurethane or polyvinyl chloride is applied to a release surface of the release sheet, and Manufactures synthetic leather made of a resin sheet in which the state of the release surface is faithfully transferred to the surface of the molded product. The release sheet used in this molding step includes:
For example, the surface of a base sheet made of paper or the like is released with a thermosetting resin or the like such as a polyolefin resin such as polypropylene or poly (4-methylpentene-1), an organic silicon compound, an alkyd resin, or a modified alkyd resin. Laminated sheets formed with layers are used.

[Problems to be solved by the invention]

In the above-mentioned conventional release sheet, those having a release layer of a polyolefin-based resin cannot be used at a temperature higher than the softening point of the polyolefin-based resin forming the release layer, and its use range is narrow. In addition, those having a release layer made of an organic silicon compound have no surface gloss in the obtained molded body, and those having a release layer made of a thermosetting resin can be used as a release layer having an uneven surface. It has drawbacks such as inability to do so. On the other hand, in the present invention, it is possible to use at a molding temperature of 200 ° C. or more, and furthermore, even if used repeatedly, there is no drop of the release layer, no decrease in the surface gloss of the obtained molded body, and the like. The present invention also provides a release sheet having a concave-convex surface exhibiting an excellent action in durability, and a method for producing the release sheet.

[Means for Solving the Problems]

The release sheet having an uneven surface according to the first invention is composed of a laminated sheet of a base sheet and a release layer formed on the surface of the base sheet, wherein the release layer is ,
It is formed by a cured resin film of a curable phosphazene compound, and the surface of the cured resin film has
An uneven pattern is formed. Further, the release sheet having an uneven surface according to the second invention is the release sheet according to the first invention, wherein neutral paper is used as the base sheet. Further, the method for producing a release sheet having an uneven surface according to the third aspect of the present invention comprises a step of forming a coating layer with a coating agent containing a curable phosphazene compound as a main component on the surface of the substrate sheet, A step of partially polymerizing the curable phosphazene compound in the coating layer, a step of embossing the surface of the coating layer in a partially polymerized state, and a step of completely polymerizing the curable phosphazene compound in the coating layer Thus, a release sheet having an uneven surface by embossing is obtained. In the present invention having the above constitution, the coating agent for forming the coating layer is mainly composed of a curable phosphazene compound, and other curable compounds added as a minor component to the curable phosphazene compound. A compound composition to which a compound, a polymerization initiator, an organic or inorganic filler, a diluting solvent, and other additives are added as required is used. The curable phosphazene compound, which is a main component in the coating agent, has a general formula [NP (X) _p (Y) _q ] _n (where X and Y are reactive with ultraviolet irradiation, electron beam irradiation, or heating). A group having a saturated bond, for example, an acryl group, a methacryl group, a vinyl group, an allyl group, a group containing these groups, p ≧ 0, q ≧ 0, p + q =
2, n is usually a polymerization degree of 3 to 18), and typical examples thereof are 1,1,3,3,
5,5-hexa (methacryloylethylenedioxy) cyclotriphosphazene, 1,1,3,3,5,5,7,7-octa (methacryloylethylenedioxy) cyclotetraphosphazene and the like are used. Most of the curable phosphazene compounds are in a liquid state. The curable phosphazene compound used as a main component in the coating agent may, of course, be a mixture of two or more. Curing of the curable phosphazene compound, as described above,
UV irradiation, electron beam irradiation, or heating is performed. When UV irradiation is used, for example, acetophenone, benzophenone, azobisisobutyronitrile, 1-hydroxycyclohexyl phenyl ketone, dibenzoyl, dibenzoyl A photopolymerization initiator, such as benzoylmethyl ether, p-chlorobenzophenone, p-methoxybenzophenone, benzoyl peroxide, di-t-butyl peroxide, is added in an amount of about 0.05 to 5 parts by weight based on 100 parts by weight of the curable phosphazene compound. Is done. When the amount of the photopolymerization initiator added to 100 parts by weight of the curable phosphazene compound is less than 0.05 part by weight, the polymerization reaction of the phosphazene compound is not uniform, and when the amount exceeds 5 parts by weight, the polymerization is performed. Since the amount of radicals generated during the reaction becomes large and the molecular weight of the polymer formed by the polymerization reaction becomes too small, a release layer of good quality cannot be obtained in any case. When the curing of the curable phosphazene compound is performed by heating, for example, in the coating agent,
Methyl ethyl ketone peroxide, benzoyl peroxide, t-butyl hydroperoxide, cyclohexanone peroxide, lauroyl peroxide, p-
Chlorobenzoyl peroxide, di-t-butyl peroxide, di-t-butylperoxybenzoate,
Polymerization initiators such as organic peroxides such as diacetate, and amine compounds such as N, N-diethanol-p-toluidine, methylethylamine, diphenylamine, t-butylamine, dimethyl-p-toluidine, and the like are used as curable phosphazene compounds It is preferable to add a small amount of 1 part by weight or less based on 100 parts by weight. Substrate sheet to apply a coating agent composed mainly of a curable phosphazene compound is a sheet which is usually used as a substrate sheet of release sheet, mainly basis weight 50 to 300 g / m ² about paper Or synthetic paper is used,
Particularly, neutral paper having excellent properties in heat resistance strength is preferable. Further, as the base sheet, not only uncoated paper but also coated paper having a coating layer formed of an inorganic material such as clay or an organic material such as polyvinyl alcohol can be used. When using a coated paper having an organic coating layer such as polyvinyl alcohol, it is desirable that the surface of the coating layer to which the coating agent is applied be subjected to corona discharge treatment. The coating layer formed of a coating agent containing a curable phosphazene compound as a main component has a thickness of about 0.1 to 100 g (solid component) / m ² , preferably about 0.5 to 50 g (solid component) / m ² . The surface is formed by, for example, roll coating, gravure coating, knife coating, bar coating, comma coating, spray coating, dipping coating, rod coating, curtain flow coating, kiss coating, extrusion coating, or the like. Coating layer formed on the surface of the base sheet, that is, a coating layer with a coating agent containing a curable phosphazene compound as a main component, a pre-curing step of partially polymerizing the curable phosphazene compound in the coating layer. Is cured by a post-curing step of completely polymerizing the curable phosphazene compound in the coating layer, and between the pre-curing step and the post-curing step, the surface between the coatings is subjected to embossing. . The curing step of polymerizing the curable phosphazene compound in the coating layer is performed by ultraviolet irradiation, electron beam irradiation, or heating. For example, when curing by ultraviolet irradiation, a light beam having a wavelength of 180 to 550 nm is emitted. An ultraviolet irradiation device equipped with a quartz mercury lamp, ultraviolet curing carbon arc, high flash lamp, etc. as a light source, and an electron beam irradiation device having an energy of 50 to 2000 KeV should be used for curing with an electron beam. It is suitable. Adjustment of the degree of curing of the phosphazene compound in the pre-curing step of partially polymerizing the curable phosphazene compound in the coating layer, for example, by adjusting the irradiation dose when ultraviolet irradiation, and in the case of electron beam irradiation A coating material containing two or more catalysts having different reaction temperatures for catalysis, by changing the irradiation dose or the oxygen concentration in the atmosphere, and further, in the case of heat treatment, by changing the heating temperature. In the first curing step, the curable phosphazene compound in the coating layer is partially polymerized so as not to be completely cured but to exhibit a dry state. After the curable phosphazene compound in the coating layer is partially polymerized, embossing applied to the coating layer surface is most commonly transferred by an embossing roll having an uneven surface, but a belt method or a pattern is used. A pressing method using an attached die or the like can also be used. The curing means in the former curing step of partially polymerizing the curable phosphazene compound in the coating layer formed on the surface of the base sheet and the latter curing step of further completely polymerizing the same are as described above. The curing step and the post-curing step may be the same type of curing means or different types of curing means. .

[Operation]

The release sheet of the present invention comprises a substrate sheet and a cured resin film of a curable phosphazene compound formed on the surface of the substrate sheet, and the surface of the cured resin film has an uneven pattern. It is formed and has good adhesive strength between the release layer made of the cured resin film and the base sheet, and also has excellent action in heat resistance, weather resistance, chemical resistance, abrasion resistance, etc. It plays and exhibits a moderate release property. Further, the method for producing a release sheet of the present invention comprises the steps of: forming a coating layer of a coating agent containing a curable phosphazene compound as a main component on the surface of a base sheet; and then curing the curable phosphazene compound in the coating layer. Is partially polymerized, in such a state, the embossing process is performed on the coating layer surface, and thereafter, the curable phosphazene compound in the coating layer is completely polymerized, and the curable phosphazene compound in the coating layer is used. The coating layer in a so-called semi-cured state where the polymer is partially polymerized, that is, since the coating layer is to be embossed on the coating layer surface in a state where the plasticity still remains, the coating layer is broken by the emboss. There is no problem and the coating layer does not flow out due to the heating during the embossing, so that a high quality embossed product can be obtained.

【Example】

Hereinafter, the specific configuration of the release sheet having the uneven surface of the present invention and the method for producing the release sheet will be described based on production examples. Example 1 To 150 parts by weight of methyl isobutyl ketone, the formula Was dissolved in 100 parts by weight of the curable phosphazene compound represented by the formula, and 0.3 parts by weight of benzoyl peroxide was further added to prepare a coating agent mainly containing the curable phosphazene compound. The coating agent, a neutral paper having a basis weight of 135 g / m ² with a coating layer of polyvinyl alcohol with respect to the coated layer surface,
Coating and drying were performed using a roll coating method to form a coating layer having a thickness of 4 μm. Next, a linear filament type electron beam accelerator is used to irradiate an electron beam of 1 Mrad in an atmosphere having an oxygen concentration of 1% to partially polymerize the curable phosphazene compound in the coating layer, and to obtain a semi-cured coating layer. Was formed. Subsequently, a sheet having a coating layer in the semi-cured state,
After passing through a heating embossing roll at 120 ° C. having an embossed pattern composed of a leather pattern, heating was further performed at 150 ° C. for 30 seconds to completely polymerize the curable phosphazene compound in the coating layer. A release sheet [1] having an uneven surface was obtained. Example 2 In the manufacturing process of the release sheet in Example 1, a basis weight of 135 g / m having a coating layer of polyvinyl alcohol was used.
^In all the steps other than using acidic paper having a basis weight of 135 g / m ² having a polyvinyl alcohol coating layer instead of the neutral paper, the same steps as those in Example 1 were performed. Thus, a release sheet [2] having an uneven surface, which is the target product of the present invention, was obtained. Experiment 50 g (solid component) of polyvinyl chloride sol was applied to the release surface of each release sheet obtained in Examples 1 and 2 above.
After coating at a rate of m ² and foaming by heating at 210 ° C. for 2 minutes, the release sheet was peeled off. Further, using the release sheet that has been peeled off in the above step, the same steps as described above are repeated for the release surface of the sheet, and foam molding of polyvinyl chloride sol is performed. For [1], foam molding is repeated four times using the same release sheet,
For the release sheet [2], foam molding was repeated three times using the same release sheet. After each foam molding, the peel strength when peeling the release sheet and the polyvinyl chloride sol foam molded article, and the state of the surface of the polyvinyl chloride sol foam sheet obtained by peeling the release sheet are shown. , Will be described in a table. In the foam molding of the polyvinyl chloride sol using the release sheet [2], the paper strength of the base sheet (acidic paper) is reduced after the third use, and the deterioration is remarkable. For use, the possibility of running out of paper was predicted.

【The invention's effect】

The release sheet of the present invention can be used at a molding temperature of 200 ° C. or higher, can be applied in a wide range of molding temperature ranges, and a molded article molded using this release sheet can be used as a mold. A high-quality molded article with a faithful reproduction of the uneven pattern on the surface of the mold sheet and a glossy surface is obtained. The release sheet of the second aspect of the present invention, in addition to the above-mentioned properties, can withstand sufficient repeated use in heat molding and has excellent durability. Further, according to the method for producing a release sheet of the present invention, a release sheet having the above-mentioned various properties can be easily and reliably obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI // B32B 5/30 B32B 5/30

Claims (3)

(57) [Claims] 1. A substrate sheet and a cured resin film of a curable phosphazene compound formed on the surface of the substrate sheet, and an irregular pattern is formed on the surface of the cured resin film. A release sheet having a concave-convex surface. 2. The release sheet according to claim 1, wherein the base sheet is neutral paper. 3. After forming a coating layer of a coating agent containing a curable phosphazene compound as a main component on the surface of a base sheet, the curable phosphazene compound in the coating layer is partially polymerized. A method for producing a release sheet having an uneven surface, wherein embossing is performed on the surface of a coating layer, and the curable phosphazene compound in the coating layer is completely polymerized.