JPH0283044A - Manufacture of skin powder - Google Patents

Abstract

PURPOSE:To permit the pulverization of skin by swelling and an efficient manufacture of the powder therefrom by placing the small pieces of natural skin soaked fully with water in a pressure container, exerting, after being sealed therein, heat and pressure thereon for a predetermined time and instantaneously reducing the pressure. CONSTITUTION:When the small pieces of the natural skin soaked fully with water are placed in a pressure container and heated, after being sealed therein, to a temperature not less than the evaporation point of the water, the small pieces thereof make contact with the hot water and vapor produced therein and are made swollen thereby, whereby the interwined collagen fibers in the skin texture become disentangled. Upon the subsequent instantaneous reduction of the container pressure, the small pieces of the natural skin are pulverized by the swelling action into an aggregate of the small particles, whereby the intertwined collagen fibers are broken to facilitate the next finely dividing process by a crusher, resulting in an easy and energy-efficient manufacture of the powder of the natural skin.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for producing natural leather powder by cutting natural leather into strips and pulverizing the leather strips.

Natural leather powder is used for various purposes, such as mixing it with resin and molding it into synthetic leather, or mixing it with liquid paint and using it as a coating material. It can be made to have the same properties as natural leather in terms of flexibility, natural texture, moisture absorption and desorption properties, non-static properties, etc., and is superior to natural leather in terms of water resistance, durability, and antibacterial properties. It is a useful new material that can be endowed with specific properties.

(Prior art) Conventionally, natural leather is cut into strips, washed with water, steamed with heated steam for a predetermined period of time, dried, degreased, and then subjected to a drying process again. It was pulverized in a grinder to produce natural leather powder.

(Problems to be Solved by the Invention) As described above, in the conventional treatment process, the washed natural leather pieces are subjected to a steaming process before being sent to a crusher. The purpose of this method is to loosen the entanglements of collagen fibers, which are the main component, to facilitate and effectively crush the next step, and to efficiently manufacture high-quality products. However, this steaming process requires a considerable amount of time, and it is not possible to immediately apply it to a dry pulverizer after steaming; instead, it must be taken out of the container, dried, and then reapplied to a pulverizer. Therefore, a separate drying process is required for this purpose. Moreover, in this drying process, the collagen fibers in the leather tissue were untangled by the previous steaming process, but the fibers were contracted again, and the crushing effect by the crusher in the next process could not be obtained sufficiently. . For example, the particle size of the leather powder obtained by the pulverization process is about 40 μm at the most, and it is passed through a classifier to obtain a product powder with an average particle size of about 20 μm. However, as a result, the product yield is low at around 30%, and fine pulverization is still insufficient for mixing with synthetic resins to produce high-quality synthetic leather, and even finer pulverization has been desired. In other words, in order to produce high-quality synthetic leather that has the texture of natural leather, it is necessary to uniformly mix natural leather powder with resin and increase the content of natural leather powder, but fine pulverization is necessary. If it is insufficient, it will be extremely difficult to mix uniformly, and the distribution of natural leather powder will become quite uneven when observed microscopically using a microscope. Furthermore, the gaps between natural leather powders will become large and the amount of resin to fill the gaps will increase. increases, and the content of natural leather powder decreases in terms of volume.

The purpose of the present invention is to effectively disentangle the collagen fibers of natural leather, thereby allowing the next step of fine pulverization to be carried out sufficiently, thereby making it possible to provide high-quality synthetic leather that has the texture of natural leather. At the point.

(Means for Solving the Problems) The characteristic means of the present invention is to put a strip of natural leather sufficiently moistened with water into a sealed pressure vessel, heat it for a certain period of time to pressurize the inside of the vessel, and then pressurize the inside of the vessel. The purpose of this method is to instantly open the container and reduce the pressure to swell and crush the leather pieces in the container, and its operation is as follows.

(Function) First, we conducted various experiments to find out what method is suitable for completing the process of disentangling the collagen fibers of natural leather more effectively and in a shorter time using the conventional steaming process. The leather is simply heated by steam by contacting it with steam for a certain period of time in a pressure vessel, then instantly opening the vessel, and rapidly reducing the pressure inside the vessel to cause the leather pieces to expand and be crushed. We have discovered that compared to conventional methods that only involve the use of collagen fibers, it is possible to shorten the time and more effectively loosen collagen fibers.

In other words, when a strip of natural leather moistened with water is placed in a sealed pressure vessel and heated above the vaporization temperature of water, the strip of leather comes into contact with the high-temperature moisture contained inside and the generated steam. The whole body is swollen and the collagen fibers in the leather tissue of the natural leather are loosened. and,
As the inside of the pressure vessel becomes pressurized as it heats up, it is caused by instantly releasing the vessel and causing a rapid depressurization.
Pieces of natural leather can be crushed by the so-called swelling effect. In other words, the water contained inside the leather vaporizes and expands due to the sudden pressure change in which the inside of the container is instantaneously reduced in pressure, thereby crushing the leather tissue from the inside.

In this way, the pieces of leather become like small grains that aggregate and cut off the intertwined collagen fibers in the leather tissue.
Fine pulverization by a pulverizer in the next step can be carried out very effectively. That is, this pulverized product can be easily pulverized by applying it to a pulverizer, and a fine powder of natural leather can be efficiently produced. Then, if necessary, the particles are subjected to sieving or classification treatment to obtain a desired particle size and a product.

In addition, since the water contained inside the pulverized material obtained by this method is vaporized, the amount of water contained in the pulverized material is considerably small, so that the drying process can be performed in a short time and with less energy for drying.

(Effect of the invention) As described above, according to the present invention, natural leather powder can be easily
and can be manufactured with energy efficiency.

In addition, it is possible to obtain extremely fine powder compared to conventional methods.
Moreover, the obtained leather powder has a swollen interior and has excellent moisture absorption and desorption properties.

Therefore, when mixing this leather powder with resin to make synthetic leather, since the natural leather powder is sufficiently fine, mixing is easy and quick, and the fine powder is uniformly dispersed without agglomeration. The amount of natural leather powder can be increased in terms of capacity.
We are now able to provide high-quality synthetic leather that has the texture of natural leather and excellent moisture absorption and desorption properties. Furthermore, when a coating material is produced by mixing with an appropriate liquid or thermoplastic paint, it can be mixed easily, quickly, and uniformly, and a coating material that does not clog a spray gun or the like can be obtained. As a result, it has become possible to mass-produce fine powder of natural leather, which can produce products with properties equal to or better than natural leather, with greater advantages in terms of initial cost, running cost, and production rate. . It has now become possible to supply large quantities of natural leather compositions, synthetic leather molded products, and other products that have all the benefits of natural leather at a sufficiently low cost.

(Example) Next, an example will be shown with reference to drawings. Leather obtained by pre-processing the natural hides of animals such as cows, pigs, goats, sheep, and horses, such as soaking, lining, liming, and hair removal, and then subjecting them to alum tanning, iron tanning, etc. Preferably, cut leather produced as waste from the manufacture of various leather products is crushed, cut, etc. into pieces to produce leather strips generally 30 mm or less, preferably 5 mm or less. The shredding process may be performed in one step or in multiple steps, and in the case of multiple steps, it is desirable to combine different types of shredding treatments.

The natural leather strips thus produced are washed and, if necessary, subjected to degreasing treatment, and then subjected to a hydrolysis treatment to impregnate the strips with a predetermined amount of moisture. Note that the moisture content varies somewhat depending on the raw material, but as a guide, it should be 30 to 70%. In this example, cowhide shaving waste was used, and the moisture content was approximately 60%. This strip of leather was placed in a pressure vessel equipped with a heating device and heated at 120 to 130° C. for about 1 hour to sufficiently swell the inside of the leather. Next, the container whose pressure has increased due to the heating is instantaneously opened to cause an expansion effect due to rapid pressure reduction. The pressure inside the container at this time was approximately 2 to 3 kg/crAG.

Due to this swelling action, the leather pieces inside the container were crushed from inside and ejected from the opening, which was collected using a cyclone. This collected product has a moisture content of 50%.Next, it is put into a dry media agitation type pulverizer and stirred while blowing in dry air.The average particle size is about 30 μm and the water content is about 8%. A dry leather powder was obtained.

In addition to using dry air or heated air in this drying process, it is also possible to speed up the drying time by equipping the media agitation type pulverizer with a jacket or incorporating a microwave generator.

The leather powder dried in this manner was subsequently pulverized in a media agitation type pulverizer, and a fine powder with an average particle size of about 2.5 μm could be obtained in a pulverization time of about 30 minutes. This leather powder has a 5.5
It has a large specific surface area of about 100%, and therefore has excellent moisture absorption and desorption properties.

Furthermore, when heating the inside of the pressure vessel, heated steam may be directly introduced.

(Another Embodiment) The pulverizer may be a dry pulverizer of a different type from the media agitation type pulverizer, in which case a drying device may be incorporated to perform closed circuit pulverization, or a drying means may be provided separately. There is a method of drying the pulverized material taken out from the pressure vessel and then applying it to a pulverizer.

In addition, when the above-mentioned media agitation type crusher is used as a wet crusher and the natural leather powder is used directly as a liquid or paste resin or paint, or as a material for other leather products, the natural leather powder can be used as a wet crusher. There is no need to make it into a dry powder after pulverization, and it can be mixed and used as a raw material for synthetic leather as it is, and the drying process can be omitted, resulting in significant energy savings.

[Brief explanation of the drawing]

FIG. 1 is a flow sheet showing an embodiment of the present invention. Below Up

Claims (7)

[Claims] (1) Coarsely crush natural leather into small pieces, add water to the leather pieces, heat and simultaneously pressurize for a predetermined period of time in a closed pressure vessel, then instantly open the pressure vessel to reduce the pressure to create leather fine pieces. A method for producing leather powder, characterized in that the pieces are crushed. (2) Coarsely crush natural leather into small pieces, add water to the leather pieces, heat and simultaneously pressurize for a predetermined period of time in a closed pressure vessel, then instantly open the pressure vessel and depressurize it to make leather fine pieces. A method for producing leather powder, which comprises pulverizing pieces and further pulverizing them using a dry or wet pulverizer. (3) The method for producing leather powder according to claims 1 and 2, wherein the pressure vessel is heated by introducing heated steam. (4) The method for producing leather powder according to Claims 1 and 2, wherein the pressure vessel is heated by being equipped with a jacket. (5) The method for producing leather powder according to Claims 1 and 2, wherein the pressure vessel is heated by being equipped with a microwave generator. (6) A dry medium agitation type pulverizer is used as the pulverizer,
3. The method for producing leather powder according to claim 2, wherein drying and pulverization are carried out simultaneously in the pulverizer. (7) The method for producing leather powder according to claim 2, characterized in that the crusher is a wet media agitation type crusher.