JPH0544173A - Synthetic leather - Google Patents

Abstract

PURPOSE:To obtain a soft synthetic leather with appearance and touch feeling both closely resembling those of natural leather by providing a fibrous base material with a polyurethane wet fine porous layer followed by abrading and removing the surface film and then laminating the resultant surface with a polyurethane surface layer. CONSTITUTION:A fibrous base material is impregnated with a polyurethane resin solution followed by wet solidification to monolithically form a wet fine porous layer on the base material. Thence, the surface film on said fine porous layer is abraded and removed using e.g. sand paper, and the resulting surface is provided, through an adhesive, with a polyurethane surface layer, thus obtaining the objective synthetic leather with monolithic feeling and soft touch, excellent in smoothness, closely resembling natural leather, having surface with natural leather-like wrinkles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synthetic leather having a fine and dense wrinkled surface similar to natural leather, and having a soft touch with a sense of unity and an excellent appearance and feel.

[0002]

2. Description of the Related Art Synthetic leather is widely used for clothing, furniture, bags, bags, shoes and the like. This kind of synthetic leather is woven fabric,
A polyurethane resin solution is applied to the surface of a fibrous base material such as a non-woven fabric or knitted fabric, and then wet-solidified to form a wet microporous layer of polyurethane integrally with the fibrous base material. A polyurethane skin layer is formed. A fibrous base material is impregnated with a polyurethane resin solution, and then wet solidified to form a wet microporous layer integrally with the fibrous base material, and a polyurethane skin layer is further formed on this surface. Or the surface of a wet microporous layer formed by wet coagulating a polyurethane resin solution impregnated into a fibrous base material, the polyurethane resin solution is applied and wet coagulated to form a wet microporous layer, It is known that a polyurethane skin layer is formed on this surface.

[0003]

SUMMARY OF THE INVENTION Synthetic leather having a surface layer of polyurethane resin formed on the surface of a wet microporous layer of polyurethane resin integrally formed with the above-mentioned fibrous base material has a wet microporous layer to provide a tactile sensation. Although it is excellent and looks similar to natural leather in appearance, in order to make the appearance and feel more closely resemble those of natural leather, the polyurethane resin used is modified, or in the wet microporous layer. Various studies such as adding an additive have been made.

However, in all conventional synthetic leathers, the wrinkle pattern formed on the polyurethane skin layer is large and boned, which is far from the fine and fine wrinkle pattern formed on the surface of the natural leather. .. There is still room for improvement in terms of unity and softness.

The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, formed a polyurethane skin layer on the surface of the wet microporous layer of the polyurethane resin from which the coating film had been removed, whereby the appearance and texture were improved. The inventors have found that the above can be further improved and have completed the present invention.

[0006]

Means for Solving the Problems That is, the synthetic leather of the present invention comprises a polyurethane skin layer laminated on the surface of the wet microporous layer of the polyurethane resin formed integrally with the fibrous base material from which the film has been removed. Characterized by

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. The synthetic leather 1 shown in FIG. 1 is a synthetic leather in which a polyurethane resin solution is applied to the surface of a fibrous base material 2 and then wet solidified to form a wet microporous layer 3 of polyurethane resin integrally with the fibrous base material 2. And a polyurethane skin layer 6 laminated on the wet microporous layer 3 side of the synthetic leather substrate 4 via an adhesive layer 5.

As the fibrous base material 2, those used for ordinary synthetic leather can be used. For example, use of natural fibers such as cotton and hemp, regenerated fibers such as rayon, acetate and suf, synthetic fibers such as polyamide, polyester and polyacrylonitrile, or woven fabrics, non-woven fabrics, knitted fabrics or the like made of blended fibers thereof. You can
Further, as the fibrous base material 2, it is possible to use one on which both sides or one side has been raised, but from the viewpoint of improving the texture of the surface of the synthetic leather, one on which at least the surface side is raised is used. Preferably.

The wet microporous layer 3 of polyurethane resin formed on the surface of the fibrous base material 2 is formed by applying a water-miscible organic solvent solution of polyurethane resin on the surface of the fibrous base material 2 and then immersing it in water. Can be formed by dissolving and removing the water-miscible organic solvent in water to solidify the polyurethane resin. As the polyurethane resin, polyethylene adipate, polybutylene adipate, polypropylene adipate, polyhexamethylene adipate, polycaprolactone, polyglycol valerolactone, etc. as a polyol component polyester glycol polyurethane, polypropylene glycol polyurethane, polytetramethylene glycol polyurethane, Polycarbonate polyurethane, polytetramethylene glycol-
Polycarbonate copolymer type polyurethane or the like can be used. It is preferable to use these polyurethane resins properly according to the intended use, and the 100% modulus is selected according to the purpose from the range of about 15 to 150 kg / cm ² . As the water-miscible organic solvent used as the solvent for the polyurethane resin, an organic solvent that dissolves the polyurethane resin and is miscible with water is used, and examples thereof include dimethylformamide (DMF), dimethylacetamide (DMA), and tetrahydrofuran ( THF),
Examples include dioxane (DOX) and the like, and a mixture thereof, but DMF is usually used. The wet microporous layer 3 preferably has a thickness of 100 to 1000 μm.

On the surface of the wet microporous layer 3 formed as described above, there is a film in which bubbles are extremely fine and the surface is smooth. In the synthetic leather 1 of the present invention, the film on the surface of the wet microporous layer is removed, and then the polyurethane skin layer 6 is provided on the surface 7 from which the film is removed. Examples of the method of removing the film include a method of polishing the surface with sandpaper, sand cloth, a wire brush, a grindstone, a sand net, a brush containing sand, etc., or a method of cutting the surface with a slicing machine, a skiving machine, etc. A particularly preferred method is polishing with sandpaper, which has excellent processability. When polishing the surface with sandpaper, it is preferable to use sandpaper of meshes 120 to 600.

As the polyurethane skin layer 6, a transfer sheet in which a layer serving as a polyurethane skin layer and a layer serving as an adhesive layer are sequentially provided on a release paper, and the layer side serving as the adhesive layer of the transfer sheet is wet microporous. It can be formed by a method in which the film of the layer 3 is superposed on the surface 7 from which the coating has been removed and heated and transferred. As the adhesive in the adhesive layer 5, one-component type or two-component type polyurethane adhesives can be used. In addition, a transfer sheet in which only a layer to be a polyurethane skin layer is provided on the release paper without using an adhesive is used, and the polyurethane skin layer 6 and the synthetic leather substrate 4 are laminated and integrated by thermal lamination, and then the release paper. It can also be formed by a method of peeling. As the polyurethane resin forming the polyurethane skin layer 6, the same polyurethane resin as the wet microporous layer 3 can be used. The thickness of the polyurethane skin layer 6 is 10 to 100 when the adhesive layer is not provided.
μ is preferred. When the adhesive layer 5 is provided, the thickness of the polyurethane skin layer 6 may be 10 μm or less, and the thickness of the adhesive layer 5 is preferably 10 to 100 μm.

In the case of the synthetic leather 1 having the structure shown in FIG. 1, the fibrous base material 2 is exposed on the back side of the synthetic leather base material 4, but the wet microporous layer 3 surface When the synthetic leather substrate 4 is wound and stored after the synthetic leather substrate 4 is manufactured by removing the film until the polyurethane skin layer 6 is provided on the surface side of the substrate 4. However, the fibrous material dropped from the fibrous base material 2 is unlikely to adhere to the surface of the wet microporous layer 3. As a result, as in the case where the polyurethane skin layer is provided on the surface of the wet microporous layer to which the fibrous substance is attached,
Without impairing the smoothness of the polyurethane skin layer surface,
Even when enamel-like synthetic leather is used, it is possible to easily obtain a synthetic leather having a beautiful enamel-like surface with a smooth surface.

The synthetic leather 1 shown in FIG. 2 is formed by wet-coagulating a polyurethane resin solution impregnated in a fibrous base material to form a wet microporous layer integrally with the fibrous base material, in the wet-type synthetic leather base material 4. It has a structure in which a polyurethane skin layer 6 is provided on a surface 7 from which the film on the surface of the microporous layer has been removed, with an adhesive layer 5 interposed therebetween. The amount of the polyurethane resin solution impregnated into the fibrous base material 2 is preferably 15 to 60% by weight as the solid content weight of the polyurethane resin with respect to the weight of the fibrous base material 2.

The synthetic leather 1 shown in FIG. 3 is obtained by wet coagulating a polyurethane resin solution impregnated into a fibrous base material to form a wet microporous layer integrally with the fibrous base material. 4, a polyurethane resin solution is further applied and wet-coagulated to form a second wet microporous layer 8, and after removing the film on the surface of the second wet microporous layer 8, this film is removed. Polyurethane skin layer 6 with adhesive layer 5 on the exposed surface 7
It has a laminated structure. The thickness of the second wet microporous layer 8 is preferably about 100 to 1000 μm.

The synthetic leather 1 shown in FIGS. 2 and 3 also has a polyurethane skin layer 6 as in the synthetic leather shown in FIG.
Is not limited to the case of bonding via the adhesive layer 5, but may be bonded and integrated by thermal lamination.

The present invention will be described in more detail with reference to specific examples and comparative examples. Example 1 A solution for forming a wet microporous layer having a 100% modulus of 20 kg / cm ² as a main component and a polyester-based polyurethane as a main component was prepared, and this solution was formed from a mixed fiber of nylon fiber and rayon fiber to a thickness of 0. A 0.65 mm knitted fabric was applied to a thickness of 0.9 mm. Wet microporous layer forming solution formulation-Polyester-based polyurethane DMF solution (solid content 30%) 100 parts by weight-Cellulose fine powder 5 parts by weight-Colorant 5 parts by weight-Castor oil-based surfactant 1.5 parts by weight-DMF 170 parts by weight After coating, the solvent is removed in water at 20 ° C. to solidify the polyurethane, and dehydration is followed by drying with hot air at 120 ° C. to obtain a synthetic leather substrate having a wet microporous layer having a thickness of 0.9 mm. It was Then
From the wet microporous layer surface of this synthetic leather substrate,
The film on the surface of the wet microporous layer was removed by polishing with 180 mesh sandpaper. On the other hand, 1 on the enamel release paper
A polyester polyurethane solution with a 00% modulus of 60 kg / cm ² was applied with a knife coater so that the thickness after drying was 5 μ, and dried at 100 ° C. for 2 minutes to form a film, on which 100% modulus was applied. Is applied with a knife coater so that the thickness after drying is 20 μ, and a two-pack type polyester-based polyurethane adhesive of 15 kg / cm ² is applied.
It was dried with hot air at 00 ° C to form an adhesive layer to obtain a transfer sheet. After the adhesive layer side of this transfer sheet was superposed on the polished surface of the base material for synthetic leather, thermocompression-bonded at 100 ° C. for 5 minutes, and further heated at 70 ° C. for 48 hours to cure the adhesive by reaction. Then, the release paper was peeled off to obtain a synthetic leather. The obtained synthetic leather had a soft texture with a sense of unity, fine fine and fine wrinkles like natural leather were formed on the surface, and it was excellent in surface smoothness and good in appearance.

Comparative Example 1 A synthetic leather was obtained in the same manner as in Example 1 except that the film on the surface of the wet microporous layer of the synthetic leather substrate was not removed. The obtained synthetic leather lacked in unity and softness, and was also inferior in surface smoothness, and the wrinkles formed on the surface were large-scaled and wrinkled wrinkles.

[0018]

As described above, the synthetic leather of the present invention is formed by laminating the polyurethane skin layer on the surface of the wet microporous layer of polyurethane integrally formed with the fibrous base material from which the film has been removed. It is a synthetic leather that has a soft texture with a feeling of touch and has a fine, finely wrinkled surface similar to natural leather with a good appearance. Further, since the surface of the polyurethane skin layer is excellent in smoothness, there is an effect that a synthetic leather having a good enamel appearance can be obtained.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of one embodiment of the synthetic leather of the present invention.

FIG. 2 is a vertical cross-sectional view of another embodiment of the synthetic leather of the present invention.

FIG. 3 is a vertical sectional view of still another embodiment of the synthetic leather of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Synthetic leather 2 Fibrous base material 3 Wet microporous layer 6 Polyurethane surface layer 7 Wet microporous layer Surface from which the film has been removed 8 Wet microporous layer

Claims (1)

[Claims] 1. Synthetic leather, characterized in that a polyurethane skin layer is laminated on the surface of the wet microporous layer surface of a polyurethane resin integrally formed with a fibrous base material from which the film has been removed.