JPS6334918Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a release sheet that is mainly used when forming polymer films or when forming the surface of synthetic resin decorative laminates, and has a uniform matte surface that is unprecedented in the past. It is.

Conventionally, polyurethane resin films and polyvinyl chloride films used for synthetic leather and other industrial materials have generally been formed by a casting method using a release sheet. That is, a resin solution is applied onto a release sheet, dried, and then the release sheet is peeled off to obtain a film.

In addition, decorative laminates made of unsaturated polyester, phenol, epoxy, melamine, etc. are often manufactured by temporarily bonding a release sheet to the surface of the decorative laminate, heating and forming it, and then peeling off the release sheet. .

In addition, in the case of either a casting film or a decorative board, the mattness of the surface can be adjusted by transferring the gloss of the release surface of a release sheet having a desired matte surface in advance during casting or molding. Often.

Conventionally, release sheets with a matte surface such as these have been produced by coating a base material with a solution consisting of a matting agent made of inorganic powder such as silica or calcium carbonate, and a release agent to form a release layer. type is well known. However, this release sheet has a problem in that a stable and uniform matte surface cannot be obtained. That is, in a release agent coating solution containing the above-mentioned inorganic powder, it is difficult to uniformly disperse the inorganic powder, and the inorganic powder settles over time. Therefore,
The coating solution becomes unstable and non-uniform, and the surface of the resulting release sheet also becomes unstable and non-uniform. Furthermore, with the above coating liquid, coating streaks occur during coating, making it difficult to obtain a uniform release treated surface.

As a result of various studies to solve the above problems, the inventor of the present invention found that a stable coating solution could be obtained by using a granular olefin polymer instead of an inorganic powder as a matting agent. We have devised a release sheet with an erasable surface.

That is, the present invention is a release sheet characterized in that the release layer is composed of a release agent and a granular olefin polymer, and is a novel release sheet that has not existed in the past.

The present invention will be explained in more detail below.

1 to 3 are cross-sectional configuration diagrams of typical release sheets of the present invention, in which 1 is a base material, 2 is a release layer consisting of a granular olefin polymer and a release agent, and 3 is a release layer made of a particulate olefin polymer and a release agent. Showing the sealing layer.

As the release layer in the present invention, a release agent containing a granular olefin polymer is used. Ethylene polymers and/or propylene polymers having an average particle size of 1 to 40 microns are suitable as particulate olefin polymers. The granular olefin polymer is preferably wax-like and has a molecular weight of 1,000 or more, preferably 2,000 to 5,000. As the mold release agent, known ones such as silicone, alkyd resin, and alkyd/silicone copolymer can be used. The blending ratio of the granular olefin polymer can be appropriately selected depending on the degree of matteness, but it is preferably 1 to 60 parts by weight based on 100 parts by weight of the mold release agent in terms of solid content. In coating, it is preferable to dilute and disperse a mold release agent containing a particulate olefin polymer in a solvent such as toluene, xylene, or ethyl acetate. Coating density is 5-40
% is good. The thickness of the release layer is preferably 1 μm or more, preferably 3 to 10 μm.

Next, as the base material in the present invention, a single or composite system such as paper, polymer film, metal foil, cloth, etc. can be used.

In addition, in the case of paper, etc., before applying the release layer,
It is desirable to provide a sealing layer. Examples of sealants include polyvinyl alcohol, starch, and clay.

A more detailed explanation will be given below with reference to Examples.

Example 1 Coating in which 10 parts by weight of granular ethylene polymer (molecular weight 4000) with an average particle size of 11 μm was blended as a matting agent with 100 parts by weight of alkyd silicone copolymer, and the concentration was adjusted to 30% using toluene as a solvent. Pour the liquid onto a sheet of paper.
A mold release sheet was prepared by applying 6 g/m ² to the polyvinyl alcohol filler layer 3 prepared in advance and drying at 150° C. for 1 minute to form a mold release layer 2.

The release sheet had a medium level of matteness (surface gloss of 60%), and had a uniform matte surface without coating streaks.

A urethane film was produced by a casting method using this release sheet, and as a result, the release property was good and the matte surface of the obtained urethane film was also good. In addition, similar results were obtained in the case of melamine decorative board.

Example 2 Particulate ethylene polymer (molecular weight
A release sheet was prepared according to Example 1 except that 50 parts by weight of 4000) were added. The release sheet had a high level of matteness (surface gloss level 5%), and had a uniform matte surface without coating streaks. A urethane film was produced by a casting method using this release sheet, and as a result, the release property was good and the matte surface of the obtained urethane film was also good. In addition, similar results were obtained in the case of melamine decorative board.

Comparative Example 1 50 parts by weight of calcium carbonate powder was added as a matting agent to 100 parts by weight of alkyd-silicone copolymer, 0.5 parts by weight of sodium phosphate was added to prevent the matting agent from settling, and toluene was used as a solvent. It was prepared at a concentration of 30%. This coating solution was unstable and the matting agent settled out over time. Using this coating liquid, a release sheet was prepared in the same manner as in Example 1 except for the above. This release sheet had many coating streaks and the matte surface was uneven.

Example 3 Average particle size for 100 parts by weight of silicone resin
A release sheet was prepared in the same manner as in Example 1 except for using a coating solution containing 30 parts by weight of 11μ granular ethylene polymer (molecular weight 4000) and adjusting the concentration to 5% using toluene as a solvent. The release sheet had a high level of matteness (surface gloss level 6%), and had a uniform matte surface without coating streaks. A urethane film was produced by a casting method using this release sheet, and as a result, the release property was good and the matte surface of the urethane film was also good.

[Brief explanation of the drawing]

FIGS. 1 to 3 are cross-sectional configuration diagrams of typical release sheets in the present invention. In the figure, 1... base material, 2... mold release layer, 3... sealing layer.

Claims (1)

[Claims for Utility Model Registration] 1. A release sheet characterized in that the release layer contains a granular olefin polymer of ethylene polymer and/or propylene polymer having an average particle diameter of 1 to 40 μm. 2. The release sheet according to claim 1, wherein the release agent is silicone. 3. The release sheet according to claim 1, wherein the release agent is an alkyd resin. 4. The release sheet according to claim 1, wherein the release agent is an alkyd silicone copolymer.