JPH07118700A - Production of decorative natural leather - Google Patents

Abstract

PURPOSE:To readily produce a leather useful, e.g. for a leather good such as a bag or a purse by bringing a decorative-treatment agent containing an alkaline protease and a disulfide reducing agent into contact with the grain of an alkaline leather which is subjected to liming treatment and allowing the treatment agent to stay thereon so as to apply a decorative treatment. CONSTITUTION:An alkaline leather such as a naked cowhide already subjected to a liming process or a reliming process and having >=pH 10 is spread on a stainless flat plate directing the grain upward and a foamed polystyrene form cut into a pattern and having 1cm thickness is put on the grain in a close contact state. A decorative-treatment agent containing an alkaline protease derived from Bacillus subtilis and a disulfide reducing agent is subsequently poured into the above polystyrene pattern. After keeping this contacting state for 10hr, the polystyrene form is removed and the naked conwhide is washed with running water in a drum for 10min. A back-, suede- or velour-like decoration is given thereto and treatments such as deliming, acid treatment, tanning, neutralization, dyeing and stuffing are then applied thereto. The obtained decorative natural leather is useful for a leather product such as a bag, a purse, shoes, a furniture or clothing.

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 decorative natural leather, and more specifically, it uses alkaline protease to produce a nubuck-like, suede-like or velor-like character, pattern or pattern on the silver surface of natural leather. The present invention relates to a method for producing decorative natural leather with decoration.

[0002]

2. Description of the Related Art Leather products such as bags, wallets, shoes, furniture, and clothes have various decorations in order to arouse the purchasing power of consumers, and various decoration methods have heretofore been known. ing.

For example, a method of buffing a desired portion of the silver surface of leather to give a fine fluff, and processing it into a suede-like or velor-like leather floor surface, or by making the silver surface of the leather contract and bulge The method of emphasizing the silver surface pattern of, the method of applying pressure and heat to the coated surface of the leather with a plate or a roller to give a silver surface pattern of some animals or a pattern unrelated to the silver surface, cutting the leather, A method of sewing a silver surface and a floor surface together to form a desired decorative surface is generally practiced.

However, most of the conventional methods are physical treatments, and there is no known biochemical method for treating only the desired portion of the silver surface of natural leather with a protease to decorate it. is the current situation.

[0005]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to easily apply a nubuck-like, suede-like or velor-like character, figure, pattern or the like to a desired portion of a silver surface of natural leather. It is to provide a manufacturing method of decorative natural leather.

[0006]

According to the present invention, in a natural leather manufacturing process, an alkaline protease and a disulfide reducing agent are contained on a silver surface of alkaline leather having a pH of 10 or more after a lime picking step or a re-lime picking step. There is provided a method for producing a decorative natural leather, which is characterized in that a decorative treatment agent is brought into contact with and held to make a nubuck-like, suede-like, or velor-like decoration.

The present invention will be described in more detail below.

In the production method of the present invention, cow leather, pig leather, sheep leather,
In the process of manufacturing natural leather such as horse leather, the silver surface of alkaline leather having a pH of 10 or more after the lime picking step or the re-lime picking step is treated with a specific decorative treatment agent to obtain desired characters, figures, patterns, etc. Is applied to a desired portion of the silver surface.

The specific decorative treating agent used in the production method of the present invention contains an alkaline protease and a disulfide reducing agent as essential components. The decorative treating agent usually shows a liquid state, but it may be in a gel state so as to easily contact and hold the silver surface of the natural leather described later.

The alkaline protease contained in the decorative treating agent may be one that exhibits activity under alkaline conditions and biochemically decomposes the silver surface of natural leather, for example, B. subtilis, Genus Bacillus such as B. amyloliquefaciens; Streptomyces grisea
seus) and the like; Streptomyces genus; Aspergillus oryzae (Asp. oryzae) and other Aspergillus-produced proteases, as well as papain, plant proteases such as bromelain, and the like can be preferably mentioned, and when used alone or as a mixture. Can be used.

On the other hand, the disulfide reducing agent contained in the decorative treating agent may be alkaline as long as it softens the fibers of the natural leather and accelerates the activity of the alkaline protease. For example, thioglycolic acid or its calcium salt. In addition to ammonium salts, potassium salts, sodium salts and the like, mercaptoethanol and the like can be preferably mentioned.

The content ratio of the alkaline protease and the disulfide reducing agent is preferably in the range of 1: 1 to 1: 2 by weight ratio. Further, the content ratio of the alkaline protease or the disulfide reducing agent in the decorative treating agent is preferably 1% by weight or more, and the upper limit is not particularly limited, but it is 2 from the economical point of view.
Weight% or less is sufficient. When the content ratio of the alkaline protease is less than 1% by weight, the enzyme titer is insufficient and the desired decoration cannot be obtained, which is not preferable.

In addition to the above-mentioned essential components, a gelling agent such as starch paste such as potato starch that gels the decoration treating agent and preferably improves the stability of alkaline protease is added to the above-mentioned decoration treating agent. can do.
When the gelling agent is used, it is preferably contained in the treating agent for decoration in an amount of 2 to 10% by weight, particularly 3.5 to 5% by weight. Further, it is also possible to add a surfactant, a stabilizer, a thickener which usually improves the stability of alkaline protease, and a neutral salt such as sodium sulfate which improves the ability to decompose alkaline protease. Further, when the silver surface to be treated with a decorative treatment agent is dyed, the desired dye may be contained in an amount of preferably 0.05 to 5.0% by weight, particularly preferably 0.1 to 2.0% by weight. . By including a dye in this way, the silver surface to be treated can be decorated in a nubuck, suede or velor shape and at the same time dyed in a desired color.

The treatment agent for decoration can be prepared by, for example, a method of dispersing each component in water in the case of a liquid material, and a gelling agent in the case of a gel material. A method in which an alkaline protease and optionally a dye are dissolved in water, an alkaline agent such as sodium hydroxide is added to form a gel, and then a disulfide reducing agent and other components are added and mixed. Can be obtained by

In the production method of the present invention, the term "lime pickling" means that the leather, which is usually lined, is dipped in lime milk and the natural leather is swollen with alkali to loosen the collagen fibers of the leather, and the hair, fat, The step of decomposing and removing the surface leather layer, and the re-lime picking step usually means that after the lime picking step, after performing the dividing step and the removing step, etc., it is re-immersed in lime milk and further the collagen of the leather. It is a process to loosen the entanglement of fibers.

In the production method of the present invention, after such a lime picking step or a re-lime picking step, the decorative treatment agent is contacted with a desired portion (a portion to be decorated) of the silver surface of natural leather.
The reason for retaining is that the alkaline protease and the disulfide reducing agent, which are the essential components of the decorative treating agent, must be alkaline such that the pH is 10 or more, preferably 12 or more, which effectively acts on the silver surface of the natural leather. Therefore, after the lime picking step or the re-lime picking step, the pH of the natural leather silver surface is 10 or more, preferably pH 1
If it is 2 or more, it is not always necessary to perform the contact / holding immediately after the lime picking step or the re-lime picking step.

In order to carry out the contacting / holding, for example, a partition die for characters, figures, patterns, etc. to be decorated is set at a desired position on the silver surface of the natural leather, and the decorative treatment agent is poured into the partition die. It can be carried out by a method of holding it, a method of making the decorative treatment agent into a gel, and placing it on a desired portion of the silver surface of the natural leather to be decorated. At this time, the holding time varies depending on the types and contents of the alkaline protease and the disulfide reducing agent in the decorative treatment agent,
It is preferably 3 to 20 hours, particularly preferably 5 to 10 hours. If the holding time is less than 3 hours, the desired nubuck-like, suede-like or velor-like decoration cannot be obtained, while if it exceeds 20 hours, the natural leather thickness becomes thin,
Furthermore, it is not preferable because holes may be formed. The processing temperature can be about room temperature.

In the manufacturing method of the present invention, after the treatment agent for decoration is brought into contact with and held, a deashing step, a soaking step, a tanning step,
A natural leather having a desired decoration can be obtained by performing a normal natural leather manufacturing process such as a neutralization process and a dyeing / greasing process.

[0019]

INDUSTRIAL APPLICABILITY In the production method of the present invention, a decorative treating agent containing an alkaline protease and a disulfide reducing agent is used, so that the treating agent is simply brought into contact with and held on the silver surface of the leather to be decorated, and a nubuck state is formed. , Suede-like or velor-like decorations can be applied. Further, by incorporating a dye into the decorative treatment agent, it is possible to perform dyeing simultaneously with the decoration.

[0020]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.

[0021]

[Example 1] A bare cowhide having a pH of 12 after the re-liming process in the production process of natural leather was spread on a stainless steel plate with the silver side up, and a 1 cm-thick layer was cut into a checkerboard pattern on the silver surface. The styrene foam type was closely attached. Then, 2 parts by weight of Bacillus subtilis (trade name "Pro Leather", manufactured by Amano Pharmaceutical Co., Ltd.) and 1 part by weight of sodium sulfate were added to 100 parts of water.
After dissolved in 1 part by weight, 1 part by weight of thioglycolic acid was added and mixed, and the decorative treatment agent A prepared in advance was poured into the foamed polystyrene mold and left as it was for 10 hours. After standing, the styrene foam mold was removed and the cow hide was washed with running water in a drum for 10 minutes. Next, when the cowhide was manufactured by performing the natural leather manufacturing process below the conventional deashing process,
The silver surface of the cowhide had a nubuck checkerboard pattern.

[0022]

[Example 2] Bare kangaroo skin having a pH of 12 after the re-liming process in the manufacturing process of natural leather was spread on a stainless steel plate with the silver side facing up, and the word "natural leather" was hollowed out on this silver surface. A waterproof cardboard mold was brought into close contact. Then, 2 parts by weight of Bacillus tin butyris (trade name "Pyrase", manufactured by Novo Co.) and 1 part by weight of the red reactive dye (trade name "Drimarene" Sand Co., Ltd.) were dissolved in 100 parts by weight of water.
The decorative treatment agent B prepared in advance by adding and mixing 1 part by weight of mercaptoethanol was poured into the cardboard mold. Cover the entire bare skin of kangaroo with vinyl and leave it as it is.
It was left for 5 hours. After standing, the cardboard mold was removed, and the bare kangaroo skin was washed with running water in a drum for 10 minutes. Next, when the kangaroo leather was manufactured by performing the natural leather manufacturing process below the usual deashing process, the suede-like red "natural leather" was applied to the kangaroo leather silver surface.

[0023]

[Example 3] Naked pig skin having a pH of 11.5 after the lime picking step in the natural leather manufacturing step was spread on a stainless flat plate with the silver side up. Next, 2 parts by weight of Bacillus tin butyris (trade name "Pyrase", manufactured by Novo Co.), 1 part by weight of sodium sulfate, and 4 parts by weight of potato starch were dissolved in 80 parts by weight of water, and then 10 parts by weight of 4N-sodium hydroxide. Was added and mixed to form a paste, and then 2 parts by weight of thioglycolic acid was added and mixed to prepare a gel-like decorative treatment agent C,
It was filled in a squeezing bag and the treatment liquid C for decoration was squeezed out so as to draw a flower pattern on a part of the silver surface of the naked pig skin. Since the squeezed decorative treatment liquid C was in the form of gel, it was held on the silver surface in a floral pattern. After 3 hours, the decorative treatment liquid C was squeezed out so as to draw a flower pattern on the silver surface where the decorative treatment liquid C was not retained. After leaving it as it was for 3 hours, the naked pig skin was washed with running water in a drum for 10 minutes. Next, when the pig leather was manufactured by performing the natural leather manufacturing process below the conventional deashing process, two kinds of flower patterns of nubuck and suede were provided on the silver surface of the pig leather.

Claims (3)

[Claims] 1. In the process of producing natural leather, a treatment agent for decoration containing an alkaline protease and a disulfide reducing agent is brought into contact with and held on the silver surface of alkaline leather having a pH of 10 or more after the lime-pickling step or the re-lime-picking step. A method for producing a decorative natural leather, characterized by providing a nubuck-like, suede-like or velor-like decoration. 2. The method for producing decorative natural leather, wherein the decorative treating agent further contains a dye. 3. The method for producing decorative natural leather, wherein the decorative treating agent is in the form of gel.