JP2002180099A - Method for producing colored leather - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for coloring a leather to yellowish brown by using persimmon juice which is conventionally performed in dyeing or coloring Japanese papers, cloths, woods, etc., to yellowish brown or yellowish dark brown but is not achieved in coloring the leather because the leather can not be colored with the persimmon juice due to causing a remarkable discoloring when washed in water after colored without fixing the color. SOLUTION: This method for producing the leather colored with the persimmon juice comprises tanning the leather by using a vegetable tannin in a tanning step, then repeating a step of impregnate or applying the persimmon juice thereinto and drying several times, carrying out staking after washing in water and drying and then polishing by a glass bead to finish.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing colored leather. More specifically, the present invention relates to a method for producing a colored leather having a colorful and glossy surface by tanning a raw leather and then coloring it using persimmon astringent.

[0002]

2. Description of the Related Art Conventionally, persimmon astringent has been obtained by crushing blue persimmon persimmon, adding water to extract persimmon astringent, and squeezing and filtering the solution for fermentation and aging under sealed storage for about six months to five years. It is known as a traditional paint and dye in Japan, and has been used as a coloring agent for base paper, lacquer base, etc. and a base coating agent since ancient times. In addition, persimmon astringency contains components that have insect repellent, bactericidal and antiseptic properties,
It also works as a preservative for the above products, traditional crafts and woodwork. The color is persimmon and persimmon astringent, which has been widely used in Japanese life since ancient times, and is also a beloved color.

However, coloring a leather product with persimmon astringent does not permeate it like paper, fiber or wood, but only colors the surface of the leather. It hardly remained on the surface, and fading easily occurred, and it was impossible to color the leather surface in persimmon color.

[0004] In the tanning process of raw leather, chrome tanning and tannin tanning have conventionally been performed, but chrome tanning is now mainstream worldwide. However, since chrome tanning uses chromium metal salt, the contamination of wastewater with hexavalent chromium causes environmental pollution and the leather comes into contact with the human skin, causing allergies. There is a problem that harmful hexavalent chromium may be generated when incinerating a discarded leather product or the like. Moreover,
From the viewpoint of protection of animals, chrome-tanned leather cannot be used for leather products such as harnesses and collars of dogs, and must be made of vegetable-tanned leather.

[0005] In contrast to chrome tanning which has the above-mentioned problems, vegetable tannin tanning which is excellent in water absorbability and which can provide leather which is safe for the skin and the like has been reviewed. However, most of the vegetable tannins are extracted from the woody part of the tree, bark, fruits, roots and leaves,
The problem is that cutting down trees causes environmental destruction. In contrast, some countries have established and managed afforestation systems, but generally in the less developed countries,
Management is too late, and in some countries the country is falling hard. As a result, it is necessary to review the dependence of raw materials on trees as well as to establish a system for raising and managing them.

[0006] In addition, for the above-described tree felling, a method is known in which fruits and pods are used without cutting down the tree.
Myrobalans have been conventionally known as fruits, but there is a problem that the skin is not tight and lacks hardness. Cod pods can be used as pods. The use of these nuts and pods does not cause problems such as environmental destruction due to the overcutting of trees.

Further, in the leather surface finishing step, the surface of the conventionally-leathered and softened leather is mechanically stretched and polished with a roller (often made of brass) to tighten the silver surface, thereby improving the hardness and luster. Finished out, but with mechanical stretching and polishing with metal rollers, gloss can be obtained but not enough hardness, and color appearance is poor and color fixation is poor There was a problem.

To solve the above problems, the present inventors have
As a result of the examination, the raw leather is tanned using vegetable tannins, washed and dried, and then the leather colored using persimmon astringent is repeatedly sun-dried several times to fix the persimmon astringent, and then After removing excess persimmon astringency by washing with water, the leather is stretched and dried. After that, apply a spatula to soften the leather, then polish the surface with a glass ball and tighten the silver surface firmly to finish it, giving it a clear persimmon color,
It has been found that leather colored in a fixed color without fading can be obtained.

The persimmon astringently colored leather obtained by the above method is colored deep persimmon, without fading.
The more you use it, the deeper the color will become and the more lovable it will become.The more it is treated with persimmon astringent, the more it will be given germicidal, insecticidal and antifungal properties to the leather. An object of the present invention is to provide such a leather product and a method for producing a colored leather used for producing the leather product.

[0010]

Means for Solving the Problems The method for producing colored leather according to the present invention comprises the steps of (1) tanning the raw leather with vegetable tannins, coloring with persimmon astringent, using a spatula hook and glass beads. And (2) in the step of tanning using the vegetable tannin, wherein the tannin is obtained by extracting from cod pods. (1) The method for producing colored leather described in (1) is a gist.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

The raw hide used in the method for producing colored leather of the present invention is a raw hide from which a leather that can be colored by persimmon astringency can be obtained.
Goats for goats, such as kip, cow, steer, ox, etc.
Mammals such as kid, sheep sheep, lamb, deer, horse, crocodile,
It can be obtained by slaughtering reptiles such as lizards and snakes, and then subjecting the peeled skin to watering, lining, liming, hair removal, and the like.

The vegetable tannin used in the step of tanning the raw hide of the present invention includes xylem, bark, fruit, and the like of the plant.
Vegetable tannins extracted from roots and leaves and the like are used, and as main vegetable tannins, wattle, quebracho, chestnut, myrobalan, mangrove, and the like,
By appropriately mixing these, the hardness and the like of the leather can be adjusted and used.

Among the vegetable tannins used in the present invention, tannins extracted from cod pods are well colored when the leather is colored with persimmon astringent, and light-colored leather with high light fastness is obtained. Therefore, it is preferable because a deep and calm persimmon or persimmon astringent leather product is obtained without fading.

Cod is a leguminous plant produced in Peru and the like in South America. Conventionally, as a tannin raw material, the woody part of the tree or the bark is often used, and since the tree is cut down and used as a raw material, the environmental destruction of the tropical rain forest is promoted, which is one of the causes of flood. Using cod pods as a raw material, on the other hand, has the advantage of helping to protect forest resources and preventing environmental destruction, since it is only necessary to collect and collect pods without cutting down the trees. ing.

In order to collect tannin from cod pods, cod pods are crushed, heated, mixed with water and further crushed, and a tannin-containing liquid is extracted by natural filtration or pressure filtration. The extraction operation may be repeated, and the collected extract is concentrated and imported in liquid or solid form.

The tannin tanning is performed using the vegetable tannin. As a conventional method, a tannin solution whose concentration is changed in 2 to 5 steps is used sequentially from a low concentration to a high concentration,
After immersing the raw leather in each of them and allowing the liquid to fully penetrate, pH
Is adjusted and heated so that the tannin adheres to the skin. Since one tannin treatment takes about 10 to 15 days, it takes one to two months to complete two to five tannin treatments. After the last treatment, wash with water, alkali, neutralize with acid (bleach)
To remove excess tannin, dehydrate and finish the tanning step.

Also, recently, instead of the above-mentioned tanning method, a raw leather (skin after lime pickling) and 20 to 30 weights of the raw leather are put on a drum.
A fast tanning method has been practiced in which a tannin solution having a constant concentration of% is added and tanning is performed by rotating the tannin solution for 24 to 30 hours.

Next, the leather thus treated is immersed in a persimmon juice solution to impregnate the persimmon juice, and then dried under the sun for 2-3 days. Next, the leather is immersed in the persimmon juice, or the persimmon juice is applied to the surface of the leather two to three times, followed by drying in the sun. The coloring and sun-drying operations using the persimmon juice solution described above are further performed for 1 to 5
Repeat several times. By doing so, persimmon astringency can be fixed on the surface of the leather, and a desired persimmon color can be obtained. When the last operation is completed, wash with water to remove excess persimmon juice. The color may be slightly discolored by washing with water. After washing with water, the leather is stretched by stretching and dried.

The above-mentioned sun-drying is desirably performed under sunlight, and it is preferable that the sun-drying is carried out on cloudy and rainy days. Since sunlight is affected by the weather and the intensity of light changes yearly, it is necessary to change the conditions for drying the sun in accordance with the daylight hours depending on the season. It is preferable to irradiate in sunlight under 4 to 5 days for winter days, compared to 2 to 3 days in summer day. The sunshine time of the sun-dried day is 5
It is preferable to adjust so as to be 7 hours.

In the case of using sunlight as described above, since the production conditions change yearly, it is difficult to carry out constant production. Therefore, an artificial ceiling using a light source containing ultraviolet rays and infrared rays is used instead. Setting sun-dry conditions and performing sun-drying under that condition is to obtain conditions close to sun-drying throughout the year for 24 hours without worrying about the weather, and to reliably produce colored leather within a fixed time Will be able to As a result, the time required for the production becomes constant, the production can be performed as planned, and leather of a constant quality can be obtained, which is preferable. As the device, an ultraviolet irradiation device that is usually used for ultraviolet irradiation is used.

By performing the above sun drying, the color adheres to the surface of the leather, and by repeating the sun drying, the color becomes darker, and a desirable persimmon color can be obtained. If you want a light persimmon color, dry it two or three times, and if you want a dark persimmon color, dry it three to six times.
The desired color is obtained. If a deeper persimmon color is desired, the sun drying can be performed more times than the above.

Next, the colored leather is dried and then spatulated. In spatula hanging, leather is pulled one by one against the colored surface in the horizontal direction, the surface is squeezed using a spatula, and the leather fibers are rubbed and softened. Spatula hanging, in the case of handwork, for example, about 30 cm square leather, about 2
It is preferable to stretch the leather in four directions from the center of the leather for up to 3 minutes. To mechanically apply a spatula, for example, use the “One Roll Staking Machine”
Using [Watanabe Seisakusho Co., Ltd.], a spatula can be hung at a speed of 40 to 70 pieces of leather per hour at a size of 30 to 50 cm square.

Examples of the spatula include a bamboo spatula, a wooden spatula, a plastic spatula and the like, and a bamboo spatula is most preferable.
Further, a spoon-shaped one can be used instead of the spatula. The shape can be a shape with a handle attached to a dish like a scoop, a spoon, a rice scoop, etc., but since a considerable force is applied when hanging with a spatula, it does not break or bend, and has elasticity Are preferred.

After applying a spatula, the surface of the leather is polished and finished using a glass ball. For finishing with a glass ball, the surface of the leather is lightly polished with a glass ball in a certain direction. After polishing the surface of the leather in a certain direction, it may be polished in a certain direction perpendicular to the direction. Polishing conditions are as follows: a single piece of leather should be polished for 1 to 2 minutes under a pressure of 5 to 7 kg / cm ^2. become. In polishing, it is preferable to polish the leather so as to have a uniform thickness so that the surface of the leather does not become uneven or wavy.

A glass ball used for polishing is usually a circular spherical glass ball. The material of the glass is not particularly limited, but quartz glass, agate, and the like are preferable. Also,
The shape is preferably spherical because any surface can be used in the polishing step, but a hemispherical or elliptical shape can also be used.

By polishing the surface of the leather with a glass ball as described above, the surface softened by the spatula is firmly tightened, and at the same time, the heat generated by the friction during the polishing with the glass ball is colored. By adding to the leather, the color changes to a darker color, and a deeper persimmon color or persimmon astringent color can be obtained. It is thought that the color is burned by the frictional heat and changes to a deep color. The color increased by the polishing of the glass ball as described above can maintain a calm persimmon color or persimmon astringent color for many months without fading.

As described above, the method for producing colored leather of the present invention can produce leather colored by persimmon astringency. The obtained colored leather is colored deep persimmon or persimmon astringent without fading by passing through a tannin tanning process, a coloring process with persimmon astringent and a finishing process by polishing with a spatula and a glass ball. Its color does not change over the years, and the more you use it, the more you will get a leather product that will become more attached. Examples of the leather products include bags, bags, shoes, and the like.

[0029]

[Example] Example 1 100 kg of calfskin after lime pickling
Into a drum-rotating leather tanning machine, and add 20 kg of tannin agent (trade name "Granofin TA" manufactured by Clariant, 50% tannin concentration) extracted from cod pods at 25-30 ° C.
Rotate the drum for hours to perform tanning. Next, the calfskin after tanning is dried by sequentially washing with water, lime, acid neutralization and washing with water. Put the dried leather into persimmon juice solution (5% concentration) 2
Soak for a while, lift up and dry in the sun for 3 days on a summer day. Next, the persimmon juice liquid is applied twice to the colored surface of the dried leather (hereinafter, referred to as a colored surface) and dried in the same manner as above. The above persimmon juice is applied twice to the colored surface again, dried in the same manner as above, then washed with water and dried.

Animal oils and vegetable oils are added to colored and dried leather to rub it and soften, then mechanically pulled and dried, and then a staking machine equipped with a bamboo spatula (Co., Ltd.)
(Watanabe Manufacturing Co., Ltd.) for 1 minute. Then, the surface of the leather was polished and finished for 2 minutes using a finishing machine equipped with spherical glass balls to obtain light-colored persimmon-colored leather. The calf leather bag obtained from the leather,
The product was finished in a deep perishable persimmon color, and after 5 years of use, the color hardly changed, and the color fastness was extremely high.

[0031]

The method for producing colored leather according to the present invention comprises the steps of tanning raw leather with vegetable tannins, coloring with persimmon astringent, finishing with a spatula hook and polishing using glass balls. By doing so, leather colored in persimmon color or persimmon astringent color that could not be obtained conventionally can be obtained, and the leather products obtained using that leather will express the deep, calm persimmon color of ancient Japan, on the surface, Moreover, there is an effect that it is possible to provide a leather product which can maintain a constant color for many months without fading.

Further, in the above-mentioned tannin tanning step, by using tannin obtained from cod pods, persimmon color with further depth is obtained, colored leather with less fading is obtained, and the tree is not cut down further. Therefore, an effect that environmental destruction can be prevented can be obtained.

Claims (2)

[Claims] 1. A method for producing colored leather, comprising sequentially performing a step of tanning a raw hide with vegetable tannin, a step of coloring with persimmon astringent, a finishing step with a spatula and polishing using a glass ball. Method. 2. The method for producing colored leather according to claim 1, wherein in the step of tanning with the vegetable tannin, tannin obtained by extracting from cod pods is used.