JPS6128000Y2 - - Google Patents

Description

[Detailed description of the invention] This invention relates to a release paper used in the production of synthetic leather, and is particularly concerned with a protective film that can provide a synthetic leather surface with a surface that is free from scratches, uneven gloss, or uneven patterning. A release paper containing the same material is provided.

Normally, when producing synthetic leather, a release paper is used on which a synthetic resin layer that has no affinity for the synthetic resin for synthetic leather is formed on the base paper surface, and the release surface condition is transferred to the surface of the synthetic leather. The desired gloss, matte, or grained leather surface is obtained.

This release paper is generally made by providing a clay coat layer or a subbing layer such as a polyethylene resin layer on the base paper surface, and forming a release resin layer such as silicone resin, polypropylene resin, or polymethylpentene resin thereon. If necessary, the surface of the releasable resin layer is embossed.

The undercoat layer may be omitted depending on the quality of the base paper and the synthetic resin used.

Among the above-mentioned conventional release papers, those using silicone resin generally have a drawback that it is difficult to control the gloss of the surface, and the gloss of the synthetic leather surface becomes monotonous.

In addition, those using polypropylene or polymethylpentene resin are preferable because the gloss of the cooling roll surface can be changed relatively easily during extrusion coating of the resin. The surface hardness of the layer was low, and it was easily susceptible to scratches, scratches, or uneven gloss, and required extremely careful handling.

The present invention provides a release paper that eliminates the above-mentioned drawbacks, and the base paper is coated with a release resin by extrusion, and at the same time as lamination, the desired surface condition such as gloss, matte, fine unevenness pattern, etc. is created in advance. The surfaces of the protective film provided with are brought into contact and bonded together.

Hereinafter, the present invention will be explained in detail with reference to drawings of embodiments.

The drawing shows a partial sectional view of an embodiment of the release paper of the present invention, 1 is a base paper, 2 is a release resin layer, 3 is a protective film, and the base paper 1 is kraft paper, coated paper, or high-quality paper. Paper or synthetic paper having appropriate supporting properties such as the like is used, and the releasable resin layer 2 is formed by extruding polypropylene resin or polymethylpentene resin to cover and laminate the upper surface of the base paper 1. The protective film 3 is made of polyethylene, polyester, nylon, cellulose film (cellophane), or ethylene, which has a smooth glossy surface, a matte surface with minute irregularities, or a textured surface that matches the grained surface of the leather. A resin film selected from vinyl acetate copolymer, polypropylene, etc. is used.

The polypropylene resin used for the mold release resin layer 2 has no affinity with polyurethane resins used in the production of synthetic leather, and has poor releasability, as well as poor heat resistance, film properties, and extrusion suitability. A commercially available extrusion coating suitable for forming a releasable resin layer is used, and the resin layer usually has a thickness of 20 to 40 μm.
The thickness is appropriate.

In addition, the protective film 3 is selected from a material with good temporary adhesion to the above-mentioned mold release resin, and when the mold release resin is polypropylene, the protective film 3
If the mold release resin is polymethylpentene resin, a polypropylene resin film is suitable, and this protective film 3
The thickness of is preferably in the range of 5 to 20μ, and the thickness is 5μ
If the thickness is less than 20 μm, tearing will occur due to the external force of peeling, making peeling difficult, which is not preferable, and if the thickness is 20 μm or more, the strength will be higher than necessary and it will be uneconomical.

The protective film 3 is laminated simultaneously with the extrusion coating of the release resin layer 2 onto the base paper 1. For this reason, the temporary adhesion of both layers is performed well, and the surface condition of the protective film 3 is accurately imparted to the upper surface of the releasable resin layer 2.

Since the release paper of the present invention has the above structure, in the synthetic leather manufacturing process, for example, the protective film can be peeled off immediately before applying a polyurethane resin solution onto the release paper, and the surface condition of the protective film can be accurately transferred. A coating film of a polyurethane resin solution, which will become the surface layer of the synthetic leather, is formed on the surface of the imparted mold release resin layer, and after appropriate drying and curing, a two-component curing polyurethane resin adhesive, for example, is applied, and the raised base fabric is immediately pressed and heated. After sufficient adhesion, the base paper having the releasable resin layer is peeled off.
Synthetic leather having a surface directly transferred from the surface state of the protective film is obtained.

Therefore, the release paper of the present invention completely maintains the release resin layer in the necessary surface condition with the protective film until immediately before use, and eliminates the scuffs, scratches, and scratches that are seen in conventional release paper. The practical effect is extremely large in that the occurrence of uneven gloss and uneven molding can be prevented.

[Brief explanation of the drawing]

The drawing is a partial sectional view of an embodiment of the release paper of the present invention. 1... Base paper, 2... Release resin layer, 3... Protective film.

Claims (1)

[Scope of utility model registration request] A release paper having a protective film in which a polypropylene or polymethylpentene resin is extrusion coated and laminated onto a base paper, and at the same time a protective film surface provided with a desired gloss or a fine uneven pattern is bonded to the upper surface of the protective film.