JPH03220300A - Manufacture of nonporous moisture-permeable waterproof coating leather for, e.g. the upper of shoes - Google Patents

Abstract

PURPOSE: To inexpensively obtain a leather excellent in moisture permeability and waterproofness and suitable for uppers of shoes by forming a void-free coating layer composed of polyurethane resins of water-soluble glycols on the surface of a natural split leather or a general leather having a silver surface layer.

CONSTITUTION: The natural split leather obtained by removing a surface layer of leather subjected to rubbing treatment and scarfing 23 inside skin layers or general leather having a silver surface layer is prepared and a void free coating layer 3 composed of polyurethane resins derived from water-soluble glycols is applied to the surface of the leather 1 through an adhesive layer 2 to obtain the void-free moisture permeable waterproof coating leather. By this method, the surface of the split leather can be brought to an outer shape well similar to general leather having a silver surface and the water absorbability of the general leather having the silver surface layer can be effectively removed.

COPYRIGHT: (C)1991,JPO

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for manufacturing leather, and in particular, it can be widely used as a material for the uppers of shoes such as athletic shoes, and requires special processing. The present invention relates to a method for manufacturing leather treated with.

[Prior art] A grain layer (Gr layer) generally used as a material for the upper of shoes.
The disadvantage of leather having ain) is that it is expensive since it has a surface layer on its upper surface. Therefore, it is difficult to widely use this leather as a popular shoe upper for athletic shoes and the like. Therefore, we developed split leather that satisfies both economic efficiency and practicality.
The reality is that chamois leather has become popular.

However, split leather is obtained by removing the epidermal layer of the leather that has been subjected to the shaving process, and then scabbing the inner skin layer for two to three layers. Therefore, its structure is not dense like the epidermis, but rather a porous reticular layer, and no waterproof properties can be expected. Therefore, products are manufactured by forming a waterproof coating layer or a microporous moisture permeable coating layer on the surface.

[Problem to be solved by the invention] However, the conventional polyurethane coating (hereinafter referred to as PU
In the case of split leather with fine pores formed through processing such as co-coating, when manufacturing shoes using this leather as the upper, moisture wicking and other moisture permeability can be expected, but moisture permeability is The method is microporous (POROUS)
TYPE), it has the drawback of allowing moisture to flow back into the shoe from the outside and permeate into the shoe, and as a result, it cannot be expected to have commercial value as a waterproof shoe.

The properties required for the upper of a shoe are that it has enough moisture permeability to allow sweat and bad odors to escape from the inside of the shoe to the outside, but that moisture, or water molecules, from the outside can penetrate into the inside of the shoe. It is most desirable to be able to guarantee a one-way water flow state in which the backflow phenomenon is blocked.

However, as mentioned above, conventional shoe uppers that are designed to be waterproof cannot be expected to be breathable at all, and those that are designed to be breathable cannot be expected to be waterproof. It did not have desirable marketability as a shoe upper.

[Means for Solving the Problems] The present invention provides a non-porous coating by applying a coating layer made of water-soluble glycol polyurethane resin to the surface of natural split leather or general leather having a grain layer. This is a method for producing non-porous, moisture-permeable, waterproof coated leather for shoe uppers, etc., by forming a coating layer.

[Work] The operation of this invention is as follows.

(1) Vapor-type microscopic moisture such as foot odor and sweat is treated as it is, and evaporates smoothly.

(2) When water with large particles, that is, water in a liquid state, tries to penetrate from the outside, the dense structure of molecules in the adhesive layer can effectively suppress the penetration of water.

(8) That is, the present invention provides a non-porous, moisture-permeable, waterproof polyurethane-coated leather that can exhibit the good commercial properties of one-way water passage required for the upper of shoes. It is.

[Example] Next, a method for preparing raw materials necessary in the present invention and a method for forming a coating layer of the present invention will be specifically described.

1. Preparation of the raw material of the present invention 1) Using natural leather with a base grain layer or split leather with the grain layer separated from natural leather as a material, physicochemical toughness processing appropriate for PU cocoing. administer.

The company's method uses a well-known company rule that reacts with the active groups of the leather protein collagen to form ladder bonds between its molecules, thereby stabilizing the molecular structure. Company regulations include inorganic regulations such as chromium salts, aluminum salts, and iron salts, and organic regulations such as aldehydes and unsaturated oils. Depending on the type of leather, a known U-character processing method suitable for the properties required for the present invention, ie, PU coating, may be used.

2) A? A known special paper is prepared by coating a patterned polyurethane film with polyethylene, polypropylene, silicone, etc. for expressing an embossed pattern, and is used as the release paper of the present invention.

3) Solvent type polyurethane MO using hydrophilic glycols for coating layer
Prepared with NO and two-component resins.

4) Crosslinking agent Use any crosslinking agent such as polyisocyanates or melamine resins.

5) Solvent Any polar organic solvent may be used as long as it is a solvent corresponding to polyurethane resin which is naturally volatilized and removed after the coating process is completed.

2. Manufacturing method for coating solution (polyurethane compound) Polyurethane, crosslinking agent, and solvent at a weight ratio of 80%:5%, respectively.
A viscous coating solution is prepared by placing the mixture in a mixing tank at a preparation ratio of 15% and stirring at room temperature for about 20 minutes at 400-120 ORPM.

3. Method for producing moisture-permeable waterproof coated leather of the present invention According to the process example of FIG. 2, the process is as follows.

(1) A polyurethane compound for leather (sk
Apply in resin) 5 uniformly and dry smoke 6 to 80
Dry for about 1-2 minutes at a temperature of ~160℃ for 10-30 minutes.
A dry film 4a having a thickness of μ is made and transported.

(2) The coating solution 7, ie, the adhesive polyurethane compound, is uniformly applied onto the dry film 4a to form a wet coating film 7a having a coating thickness of 10 to 50 μm.

(3) Split leather or general leather 8 is placed on this coating film 7a and bonded under pressure, and dried in a drying platform 10 at a temperature of 70 to 150° C. for 2 minutes or more.

(4) The dry leather 8 and release paper 4 are placed on the release roller 11
Divide by.

At this time, the PU co-coating solution forms a firm coating layer on the leather, and at the same time, the embossed pattern is transferred as it is by pressure with the release paper 4, forming a pattern on the surface, and the finished product. Become.

The product thus obtained is as shown in Figure 1.
It consists of a leather l, an adhesive layer 2, and a polyurethane coating layer 3.

The leather of the present invention completed as described above has moisture permeability (1
000, /go, 24HR8 or higher), it has a good waterproof effect against moisture that permeates from the outside, while odor and water vapor inside the shoes are easily disposed of to the outside, making it comfortable. Not only does it have the characteristics of a shoe relic, it also has a beautiful appearance and good feel due to the ease of processing that is unique to polyurethane, and it is durable due to its high coating strength.
The longevity of the shoes is guaranteed in terms of weather resistance, and they have high quality commercial value.

Table 1 shows the leather treated with known PU cocoing (
- Compare the properties of Master Craftsman Leather) and that of the present invention.

(Leaving space below) Table 1 When applying the moisture-permeable waterproof coating of the present invention to split leather, the surface coating film has an external shape very similar to that of leather with a general grain layer. Product quality can be greatly improved. In addition, when the coating layer of the present invention is applied to the surface layer of general leather with a grain layer, water absorption from the outside, which is a drawback of the existing grain layer, is effectively removed. It can also greatly contribute to quality improvement.

The main purpose of the present invention is to apply it to the upper of shoes.
This can also be applied to other uses, such as furniture and clothing.

[Effects of the invention As described above, the present invention has an extremely simple manufacturing process,
The cost of raw materials for coating is low, and the resulting product has both moisture permeability and waterproof properties, and is extremely effective in improving the quality of various products including bags that use leather as the upper material. It is.

[Brief explanation of drawings]

FIG. 1 is an enlarged sectional view showing the structure of the leather of the present invention, and FIG. 2 is a process diagram showing the method of manufacturing the leather of the present invention. [Explanation of codes...Leather 2...Adhesive layer 3...Coating layer and 1 other person

Claims (1)

[Claims] 1. A shoe upper made by applying a coating layer made of water-soluble glycol polyurethane resin to the surface of natural split leather or general leather with a grain layer to form a non-porous coating layer. A method for manufacturing non-porous, moisture-permeable, waterproof coated leather for use, etc.