JP2005272725A - Leather and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an extremely soft leather having a good skin touch and also without having detectable formalin, and a method for producing the same. <P>SOLUTION: This method for tanning is performed by using glutaraldehyde in a formalin-free tanning process SP3 on raw hides housed in a rotating drum. Then, a process SP4 is performed by putting cod liver oil into the drum as tanning oil and elevating temperature while rotating. Since the drum 1 is rotated while heating, the hides are completely oxidized without having unevenness, and the treatment is quickly performed in several hours. Since the formalin is not used, it is not detected in the leather completing the process, and problems such as becoming inflamed on directly touching with a skin, etc., do not occur. Further, by heating in the process of the oil-tanning process, the tanning oil is completely spread over the fibers of the leather and hardly released to make the skin touch feeling of the leather as extremely soft and smooth. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a tanned leather having no formaldehyde detected and having flexibility, and a method for producing the same.

Tanned leather is used for a variety of purposes, but formaldehyde is produced from the product, and may cause problems such as irritation if it directly touches the human skin.
On the other hand, a method for producing tanned leather in which formaldehyde is not detected from a product by performing formalin-free tanning without using formalin as a tanning agent has been proposed. In this case, for example, glutaraldehyde is used.
For example, Patent Document 1 discloses a method for producing leather that performs formalin-free tanning using glutaraldehyde or the like.
JP 2000-119700 A

  However, for example, when formalin-free tanning is performed using deer skin, the touch is firm and, for example, it cannot be used as a cosmetic cloth or a cosmetic puff. On the other hand, the moisturizing property of the skin is suitable for makeup and the like, and it has been desired to develop a method for producing tanned leather in order to make use of its characteristics.

  The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a tanned leather that is extremely soft and soft to the touch, and in which formalin is not detected, and a method for manufacturing the same.

  In order to solve the above-mentioned problems, the present invention provides a method for producing tanned leather including an oil tanning step, a first step of performing formalin-free tanning on a skin to be processed, and a rotating drum on the leather after the first step. And a second step of promoting oxidation in the rotating drum while raising the temperature in the drum.

  Moreover, the tanned leather manufactured by the said manufacturing method is suitable.

  According to the present invention, formalin is not detected from tanned leather that is a product, and tanned leather that is extremely soft and has a good touch can be manufactured. Therefore, even if it is used for a cosmetic cloth or the like, there is no fear of skin irritation or the like, and the moisture retention property of leather can be effectively utilized.

FIG. 1 is a process diagram showing a machining process according to an embodiment of the present invention, and the process includes a preparation process S1, a tanning process S2, and a finishing process S3. FIG. 2 is a schematic diagram showing a schematic configuration of the drum 1 used in the present embodiment. In the present embodiment, the raw material skin is placed in the drum 1 to perform various processes.
The drum 1 is formed in a hollow cylindrical shape, and shafts 2a and 2b are attached to both end faces, and the drum 1 rotates in the direction of arrow A when the shafts 2a and 2b rotate.
Inside the drum 1, there are provided protrusions and shelves (not shown) that protrude in the axial direction from the side surfaces, whereby the raw material skin is agitated.

  In addition, a tube is coaxially provided in the shaft 2b so that various liquids can be injected into the drum 1. In this case, liquid can be injected even when the drum 1 is rotating. In the drum 1, a heating device 5 and a temperature sensor 6 shown in FIG. 3 are provided. Reference numeral 8 denotes an operation unit on which an operator performs various operations, and includes a switch, a control knob, a display unit, and the like. A control unit 7 controls the amount of heat generated by the heating device 5 based on the operation of the operation unit 8. The output signal of the temperature sensor 6 is supplied to the operation unit 8 via the control unit 7, and the temperature is displayed on the display unit of the operation unit 8. In this case, the wiring between the heating device 5 and the temperature sensor 6 and the control unit 7 is connected via a rotary contact or the like in the shaft 2a (or 2b), and the drum 1 is in a rotating state. Power supply and signal exchange can be performed. The drum 1 has a lid structure for taking in and out the raw material skin, but the illustration is omitted for the sake of simplicity.

  The preparation step S1 shown in FIG. 1 is a step of removing unnecessary portions from the raw material leather when performing leather processing. In the present embodiment, the surface neutralization treatment SP1 and the refreshing SP2 are performed. The surface neutralization treatment SP1 is a treatment for neutralizing the skin surface. The raw material skin is put in the drum 1, and a predetermined amount of water and salt is added, and the drum 1 is rotated for about 10 minutes. Add sodium bicarbonate water and rotate drum 1 for about 15 minutes. Thereafter, the raw material skin is taken out from the drum 1 and subjected to a refreshing process. The refreshing process is a process of stripping off meat chunks, fat chunks, connective tissue and the like on the inner surface of the skin.

  After the above processing, the process proceeds to the tanning step S2 shown in FIG. In the tanning step S2 in the present embodiment, a formalin-free tanning step SP3 not using formalin and an oil tanning step SP4 performed thereafter are performed.

Formalin-free tanning SP3 is performed in the following procedure. First, the raw material skin after the preparation step S1 is put in the drum 1, and water, a small amount of salt, an activator, and sulfuric acid, which are about 1.5 to 2 times the raw material skin, are injected from the tube and rotated for about 1 hour. After that, a small amount of sodium chlorite is injected (about 2 to 10% of the raw material skin weight, and in the following, when the amount is displayed as a percentage, the ratio to the skin weight in the drum), and the drum 1 is rotated for about 15 hours. to bleach. The reason why the bleaching is performed before adding the tanning agent in this way is that the color of the hair root portion still remains even if the bleaching is performed in the previous step. The root of hair is bleached by this chlorine bleaching treatment.
Then, after neutralizing by adding several percent of sodium thiosulfate content, the solution in the drum 1 is drained from a drain pipe (not shown).

Next, a predetermined amount of water and about 10 to 30% of salt are poured into the drum 1 and rotated for about 30 minutes. The reason for using salt is to prevent the raw material skin from expanding and wiping. After this treatment, the solution in the drum 1 is drained.
Then, 15 to 40% of water and several to 20% of anhydrous bow glass are injected to rotate the drum 1 for about 20 minutes. Further, several to 10% of formic acid is added and the rotation is continued for about 30 minutes. Thereafter, the solution in the drum 1 is drained.

  Next, about several to 10% of glutaraldehyde is poured into the drum 1 and rotated for about 3 hours. That is, gluta tanning using glutaraldehyde is performed. After that, the tanning is progressed in the drum 1 almost overnight.

  Thereafter, the drum 1 is rotated for about 30 minutes, a small amount of sodium acetate is added, and the drum 1 is rotated for about 1 hour. Further, a process of injecting a small amount of baking soda and rotating the drum 1 for about 30 minutes is performed three times in succession, and finally, baking soda is injected again and the drum 1 is rotated for about 3 hours. By this treatment, neutralization proceeds. After the neutralization treatment, it is allowed to pass overnight, and the drum 1 is rotated again for about 30 minutes and then washed with water. Washing with water is performed twice with water of a predetermined temperature. The rotation time of the drum 1 is about 1 hour for the first time and about 30 minutes for the second time. By the above processing, tanning without using formalin, that is, formalin-free tanning step SP3 is completed.

Next, in order to soften the skin, a small amount of a greasing agent is put into the drum 1 and rotated for about 1 hour, and then formic acid is added and rotated for about 30 minutes. After this process, the process proceeds to the oil tanning process SP4.
First, add water to the drum 1 to condition the skin. That is, the state of the skin is adjusted so that the tanning oil can easily penetrate. Then, the drum 1 is rotated until the water becomes familiar with the skin. Next, cod oil is added and rotated while raising the temperature in the drum 1. The temperature adjustment is performed by the operator operating the adjustment knobs and switches of the operation unit 8 while watching the temperature displayed on the operation unit 8 shown in FIG. In this case, the temperature is raised in consideration of the temperature of the outside air. In this way, by rotating the drum 1 at a higher temperature, the skin in the drum 1 is forcibly promoted to be oxidized. Also, by this treatment, the cod oil is uniformly infiltrated into the leather fibers, and the cod oil is less likely to be detached from the leather fibers. In addition, the surface of the skin is moist.

  In the above process, the maximum temperature of the drum 1 is determined in advance (for example, a predetermined value is determined in the range of 55 to 70 °) and adjusted so as not to exceed that temperature. After rotating the drum 1 for a predetermined time, when the temperature is gradually lowered to a predetermined temperature (for example, a predetermined temperature is determined in a range of 45 ° to 60 °), the degreasing / greasing step SP5 is performed. Transition.

  First, in a state where the solution in the drum 1 is drained, a solvent degreasing detergent of several to 15% is put and rotated for about 30 minutes for cleaning. Thereafter, 150 to 200% water, several percent caustic soda and several percent activator are added and rotated for about 1 hour for washing. This treatment is performed three times with water washing. After the final water washing, a small amount of formic acid is injected and the drum 1 is rotated for about 20 minutes. Furthermore, the process which adds a small amount of formic acid and rotates for 20 minutes is performed 3 times. This process lowers the ph value of the skin. After that, about several to 15% of a greasing agent is added to the drum 1 and rotated for about 1 hour, and a small amount of formic acid is added and rotated for about 20 minutes. Then, the skin is taken out from the drum 1 and dried. Gara drying is a process of naturally drying the skin. The natural drying is performed, for example, as a so-called hanging drying in which a skin is hung on a predetermined bag or the like.

  Next, the process proceeds to the blanking / staking process SP6. First, as the blanking process, the empty drum 1 is peeled with a peeled leather and rotated. The dried skin is hard, but it is put into a drum and rotated to give action, and it becomes softer. After the blanking process is completed, staking is performed. Staking is a process of softening one piece of skin, and a known staking machine is used. The above is the blanking / staking process SP6.

  Next, the process proceeds to the stain removal / retane processing SP7. First, the skin that has been subjected to the blanking and staking treatment SP6 is put into the drum 1, and 400 to 600% water, several percent to ten percent of a solvent-based degreasing agent and several percent of activator are injected, Rotate drum 1 for about 2 hours. Furthermore, 700 to 900% of water is added and rotated for 90 minutes for washing with water. Then, 90 to 120% salt and a small amount of sulfuric acid are added and rotated for about 30 minutes, and 10 to 20% chlorous acid is added and rotated for about 15 minutes. Then, add several percent sodium thiosulfate and rotate for about 1 hour, add several percent baking soda and rotate for about 30 minutes, add several percent baking soda and rotate for about 90 minutes. Then, the water temperature is changed and washing is performed twice. Washing with water is, for example, about 60 minutes for the first time and about 20 minutes for the second time. The above is the stain removal process.

Next, 150 to 200% of water and a small amount of formic acid are put into the drum 1 and rotated for about 30 minutes, and then, glutaraldehyde, which is a tanning agent, is added to the drum 1 for several minutes to several tens of% and rotated for about 60 minutes. That is, another gluta tanning is performed. This is to compensate for the fact that the tanning oil may come off excessively in the stain removal process. After gluta tanning, several percent soda ash is put into the drum 1 and rotated for about 30 minutes, and further several percent soda ash is added and rotated for about three hours. Then let it pass overnight.
Then, about 500 to 600% of water is added into the drum 1 and rotated for about 30 minutes, and a few percent to 15% of a greasing agent is added and rotated for about 1 hour. After that, a small amount of formic acid is added and rotated for about 30 minutes to complete the ethane treatment.

  Next, the blanking / staking process SP8 is performed again. The empty drum 1 is filled with the skin after the stain removal / retane treatment SP7 and rotated, and then the skin is removed from the drum 1 and staking is performed by a staking machine. In addition, the leather is transported onto the rubber roll, and the paper roll is passed through in a pressurized state. This is done on the front and back of the skin.

Next, the process proceeds to the washing / softening process SP9, and the drum 1 is filled with leather and about 1000% of water and rotated for 20 minutes. Then, after draining, about 400 to 500% water, about 10 to 20% soap and several percent caustic soda are added and rotated for 40 minutes. Then, a small amount of caustic soda is added and rotated for about 1 hour to drain. Next, about 600 to 700% of water is put into the drum 1 and rotated for 15 minutes. After draining, about 600 to 700% of water is added again and rotated for about 20 minutes to drain.
Then, about 400 to 500% of water and several percent of softening agent are put in a drum and rotated for several minutes, and a slight amount of formic acid is added and rotated for about 30 minutes. Then, a small amount of formic acid is added and rotated for about 30 minutes, and further a small amount of formic acid is added and rotated for about 1 hour. Next, the skin is taken out from the drum and dried. Thus, the washing / softening process SP9 ends.

  Thereafter, the blanking process SP10 is performed, and a predetermined net is peeled and dried to complete the tanned leather.

(Effect of embodiment)
In the above-described embodiment, since the drum 1 is rotated while being heated in the oil tanning step SP4, the skin is completely oxidized without unevenness, and the processing is as fast as several hours.
On the other hand, conventionally, after oil tanning, the skin is removed from the drum and dried naturally, so it takes about half a day in summer and three days in winter, and the process time is not stable. In addition, it is difficult to completely oxidize the leather, and the tanning oil is easily detached from the fiber. In the above embodiment, there is no seasonal variation in the working time, and the quality can be stabilized.

  Further, in the above embodiment, formalin is not used, so formalin is not detected from the finished skin, and there is no problem of causing inflammation even if the skin is directly touched. Moreover, by heating in the oil tanning step, the tanning oil is completely spread over the fibers of the skin, making it difficult to separate, and the skin feel is extremely soft and smooth.

(Modification)
In the above-described embodiment, the temperature management of the drum 1 in oil tanning is performed by the operator looking at the temperature display. As shown in FIG. 3, a temperature sensor 10 for detecting the temperature of the outside air is provided, and a temperature control program is provided. A computer to be executed may be incorporated in the control unit 7 and automatically controlled while detecting the outside air temperature and the temperature inside the drum (the temperature detected by the temperature sensor 6).

It is process drawing which shows the process of one Embodiment of this invention. It is the schematic which shows schematic structure of the drum 1 used in the embodiment. It is a block diagram which shows the structure of the apparatus which heat-processes the drum 1 in the embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Drum, 5 ... Heating device, 6 ... Temperature sensor, 7 ... Control part, 8 ... Operation part, SP3 ... Formalin free tanning, SP4 ... Oil tanning

Claims (2)

In a method for producing tanned leather including an oil tanning process,
A first step of performing formalin-free tanning on the skin to be processed;
After the first step, there is provided a second step of performing oil tanning on the leather in the rotary drum and promoting oxidation in the rotary drum while raising the temperature in the drum. Production method.   A leather produced by the method for producing a leather according to claim 1.

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