JP3088831B2 - Method for producing a breathable breathable leather-like sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a leather-like sheet having excellent breathability and moisture permeability.

[0002]

2. Description of the Related Art As a leather-like sheet, a sheet-like material made of a non-woven fabric filled with a polymer elastic material and made into a porous material, or a sheet made by embossing the same, has been well known. However, this is a sheet having poor air permeability and moisture permeability because a thin film layer having a dense structure is formed on the surface.

[0003] As a method of imparting air permeability and moisture permeability to a leather-like sheet, there are, for example, a method of piercing the surface with a needle to form a hole, a method of forming a hole by pulse discharge treatment, and a method of irradiating an electron beam. Attempts have been made and various proposals have been made, such as those based on surface finishing methods. However, all of these methods require expensive equipment or complicated steps.

[0004]

As a result of extensive studies, the present inventors have found that a sheet having good air permeability and moisture permeability can be obtained by an extremely simple method such as sanding of a film layer, and completed the present invention. That
An object of the present invention is to provide a method for efficiently producing a leather-like sheet having excellent air permeability and moisture permeability.

[0005]

An object of the present invention is to provide a polymer elastic material.
This is achieved by a method for producing a breathable and breathable leather-like sheet, which comprises sanding both sides of a porous flexible sheet having a body filled in a nonwoven fabric, and then forming embossments on at least one side thereof by embossing.

The porous flexible sheet referred to in the present invention is a non-woven fabric obtained by applying an organic solvent solution or emulsion of a polymer elastic material to a non-woven fabric, coagulating the non-woven fabric and filling the non-woven fabric with the polymer elastic material. A known appropriate method may be used.

Examples of the above polymer elastic body include polymers such as polyurethane resin, vinyl chloride resin, acrylate / styrene copolymer, styrene / butadiene copolymer, urethane / vinyl chloride copolymer, and mixtures thereof. Can be mentioned. Above all, polyurethane resin is preferred in that it is close to the flexibility, texture, and feel of natural leather, and is excellent in flexibility. Mixtures are more preferred.

In the present invention, the porous flexible sheet is subjected to a sanding treatment on both front and back surfaces thereof by a belt sander or the like. By performing the sanding treatment, the coating layer having a dense structure formed on the surface is removed. The thickness of the surface removed by the sanding treatment is preferably 0.1 mm or more, and more preferably 0.1 to 0.2 mm.

Next, a leather-like grain is given to at least one of the sanded surfaces by embossing. The method of embossing is not particularly limited, and may be a known appropriate method.
In the present invention, it is preferable to color the entire sheet or the surface thereof before or after embossing. Coloring may be performed by a known appropriate method such as a method in which the sheet is dipped in a dye bath and then dried, and a method in which gravure coating is used.

[0010]

By sanding both sides of the porous flexible sheet, the skin layer having a dense structure, which hinders ventilation and moisture permeability, is removed, so that the permeability and moisture permeability are improved. The embossing gives a natural leather-like appearance.

[0011]

The present invention will be described below in detail with reference to examples. The air permeability was measured according to JIS L-1096, and the moisture permeability was measured according to JIS K-6559.
In Examples and Comparative Examples, “parts” means “parts by weight”.

Example 1 Nylon 6 short fiber (denier 1.5 denier, length 50 m)
m) non-woven fabric (basis weight 180 g / m ² , thickness 1.2)
mm) polyurethane elastomer 22 synthesized from polybutylene adipate glycol, diphenylmethane-4,4'-diisocyanate and ethylene glycol
Parts, iron oxide brown 1.5 parts, dimethylformamide 7
After impregnating with a solution consisting of 6.5 parts and performing wet coagulation, it was thoroughly washed with water and dried to obtain a thickness of 1.1 mm and an apparent density of 0.3.
A porous flexible sheet of ² g / cm ² was obtained.

Next, both sides of the obtained porous flexible sheet are sanded with a 320 mesh sandpaper, and both sides are removed by 0.15 mm, and the thickness is 0.8 m.
m was obtained.

The obtained sheet was immersed in a 0.6% by weight of a brownish gold-containing dye bath, dyed at 80 ° C. for 30 minutes, washed with water and dried. Subsequently, a leather-like grain was embossed on one side of the obtained dyed sheet using an embossing roll at a temperature of 160 ° C. and a pressure of 1 ton to obtain a leather-like sheet.

The properties of the obtained leather-like sheet are as shown in Table 1, and were excellent in air permeability and moisture permeability.

Example 2 Both sides of the porous flexible sheet obtained in the same manner as in Example 1 were sanded with a 320 mesh sandpaper, and each side was removed by 0.15 mm to a thickness of 0.8.
mm sheet material was obtained.

A leather-like grain was embossed on one surface of the obtained sheet using an embossing roll at a temperature of 160 ° C. and a pressure of 1 ton. Subsequently, 10 parts of a polyurethane resin and a reddish brown pigment 5
Parts, dimethylformamide 35 parts and methyl ethyl ketone 50 parts were colored twice with a gravure roll.

The properties of the obtained leather-like sheet are as shown in Table 1 and were excellent in air permeability and moisture permeability.

Comparative Example 1 Nylon 6 short fiber (fineness 1.5 denier, length 50 m)
m) non-woven fabric (basis weight 130 g / m ² , thickness 0.9)
mm), a polyurethane elastomer 2 synthesized from polybutylene adipate glycol, diphenylmethane-4,4'-diisocyanate and ethylene glycol
2 parts, 1.5 parts of iron oxide brown and 76.5 parts of dimethylformamide were impregnated and wet-coagulated.
Thoroughly washed with water and dried, thickness 0.8 mm, apparent density 0.
A porous flexible sheet of 32 g / cm ² was obtained.

The resulting sheet was immersed in a dye bath containing 0.6% by weight of a brownish gold-containing dye, dyed at 80 ° C. for 30 minutes, washed with water and dried. Subsequently, a leather-like grain was embossed on one surface of the obtained dyed sheet-like material at a temperature of 160 ° C. and a pressure of 1 ton using an embossing roll to obtain a leather-like sheet.

The properties of the obtained leather-like sheet are as shown in Table 1 and were poor in air permeability and moisture permeability.

[0022]

[Table 1]

[0023]

The leather-like sheet obtained by the method of the present invention has a very excellent breathability and moisture permeability and a natural leather-like appearance, since the skin layer having a dense structure is removed. I have. Since the production method of the present invention does not have complicated steps and has high production efficiency, it is extremely useful industrially.

Claims (1)

(57) [Claims] 1. A porous material in which a non-woven fabric is filled with an elastic polymer.
A method for producing a breathable and breathable leather-like sheet, which comprises sanding both sides of a flexible sheet and then forming embossments on at least one side thereof by embossing.