JPH01193399A - Production of fine natural leather powder, fine powder of natural leather obtained thereby, synthetic leather composition, coating material and molded product of synthetic leather - Google Patents

Abstract

PURPOSE:To obtain a novel leather fine powder having natural leathery feeling, touch, moisture absorbing and desorbing and antistatic properties in a large amount at a low cost, by heat-treating small pieces of natural leather while applying ultrasonic waves, disentangling collagen and finely pulverizing the resultant small pieces. CONSTITUTION:Leather, such as scrap leather, obtained as a production waste of leather products, such as cattle, pig, goat, sheep or horse, is formed into small pieces of size normally <=30 mm (preferably <=5 mm). The resultant small pieces are subsequently heat-treated while applying ultrasonic waves by piezoelectric, electrostriction, magnetostriction vibrator, etc., to disentangle collagen which is a principal component of the leather. The obtained small pieces of the leather are then subjected to fine pulverization treatment to afford a natural leather fine powder mostly having normally <=40mum size. The above-mentioned fine powder has better characteristics of resistance to water and microorganisms, durability and processability than those of natural leather.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention involves cutting natural leather into strips, heat-treating the strips of leather, loosening the entanglements of collagen, which is the main component of leather, and releasing the collagen. A method for producing a fine leather powder by finely pulverizing disentangled leather pieces, a natural leather fine powder obtained by the method, and a synthetic leather composition, coating material, and synthetic leather obtained from the fine powder. Regarding leather molded products.

The above-mentioned fine powder of natural leather can be mixed with resin and molded into synthetic leather, mixed with liquid paint and used for painting, etc.
It is used for a variety of purposes, and can be used to give synthetic leather and paint the same properties as natural leather in terms of feel, suppleness, natural texture, moisture absorption and release properties, non-static properties, etc. It is a useful new material that has properties superior to natural leather in terms of water resistance, durability, workability, and antibacterial properties.

[Conventional technology]

Collagen, which is the main component of leather, has a spiral fiber structure and is intertwined with each other. It is necessary to heat-treat the leather to sufficiently disentangle the collagen by swelling the collagen, but conventionally, the heat treatment of strips of leather has been carried out simply by steam-cooking.

[Problem to be solved by the invention]

However, heat treatment of leather strips using only steam steaming requires a considerable amount of time to sufficiently disentangle the collagen, which is a serious drawback in terms of mass production.

The purpose of the present invention is to enable heat treatment of strips of leather to sufficiently loosen the entanglements of collagen to be completed in a short time, and also to provide fine powders of natural leather, synthetic leather compositions, and coating materials. The purpose of this invention is to reduce the manufacturing cost and to supply large quantities of synthetic leather molded products at low cost.

[Means to solve the problem]

The characteristic means of the present invention is to apply ultrasonic waves to the leather strips during the heat treatment of the leather strips in order to loosen collagen entanglements, and the functions and effects thereof are as follows.

[For production]

In other words, we conducted various experiments to find out what method is best for completing the process of fully disentangling collagen in the shortest possible time by heat treating thin pieces of leather. It has been discovered that applying ultrasonic waves to a piece can effectively shorten the time compared to the conventional technique of simply heating the piece with steam.

Based on the above-mentioned new knowledge, the purpose of mass-producing natural leather fine powder with good production efficiency was fully achieved by adding a simple means of simply applying ultrasonic waves.

〔Effect of the invention〕

As a result, products with properties equivalent to or better than natural leather can be obtained, including natural leather fine powder, as well as synthetic leather compositions, coating materials, synthetic leather molded products, etc. that utilize the natural leather fine powder. It has become possible to supply large quantities of products that provide the same benefits at a sufficiently low price.

〔Example〕

Next, examples will be shown with reference to drawings.

Natural skins of animals such as cows, pigs, goats, sheep, and horses are soaked in water.
After pre-treatment such as lining, liming, and hair removal, leather obtained through tanning processes such as tanning, chrome tanning, oil tanning, alum tanning, and iron tanning, preferably from the production of various leather products. The resulting leather scraps are processed into pieces by coarse crushing, shaving, cutting, etc., to produce leather strips that are generally 3Q 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 leather strips are heat-treated using an appropriate heating device, and at the same time, during the heat treatment, an ultrasonic generator is used to apply ultrasonic waves to the leather strips at an appropriate frequency and intensity. The spiral fibrous collagen is swollen and vibrated to quickly loosen the entanglements between the collagens.

The method of heat treatment of the leather strips can be selected freely; for example, direct or indirect heating with steam or immersion in heated water are advantageous in terms of initial cost and running cost. Further, the heating temperature is generally 100 to 120°C, and heat treatment may be performed under pressurized conditions.

To apply ultrasonic waves, piezoelectric vibrators such as crystal, BaTi
Appropriate ultrasonic transmitting means can be used, such as an electrostrictive vibrator such as O3, a magnetostrictive vibrator such as nickel or ferrite.

The temperature and time of heat treatment, the frequency and intensity of ultrasonic waves, pressure conditions, etc. should be adjusted to suit the properties of the leather strips, amount of processing, and other conditions, and to ensure that fine pulverization in the post-process is sufficient and reliable. Set the settings appropriately so that it can be performed.

Leather strips with sufficiently loosened collagen are dried in a dryer on a suitable dryer to reduce the amount of collagen to 5% or less, preferably 3%.
Dry until the moisture content reaches the following.

The drying process may be one step or multiple steps.

The dried leather strips are sufficiently pulverized in a suitable pulverizer to produce a fine powder of natural leather, generally with a size of mostly 40 μm or less.

The fine powder obtained by the pulverization process is subjected to post-treatment as described in (a) or (c) below, as necessary, to obtain a natural leather fine powder as a product.

(b) The sieved material is processed through a sieve of 45 mesh or less,
The subsieve components are made into a fine powder product.

(b) Color it with an appropriate paint and dry it in an appropriate dryer to make a colored fine powder product.

(c) Classify with a suitable classifier to produce ultra-fine powder products.

Items (a) to c) below for the above natural leather fine powder:
Manufacture various products through processing.

(a) A synthetic leather composition is produced by mixing various thermoplastic resins such as vinyl chloride, various thermosetting resins such as polyurethane, and other appropriate synthetic resins with fine powder. At this time,
Since the fine powder is sufficiently fine, mixing can be carried out easily and quickly and in a uniformly dispersed state without agglomeration of the fine powder.

(b) The synthetic leather composition of item (a) above is molded using a suitable molding machine to produce a synthetic leather molded product such as a sheet.

At this time, since the fine powder is sufficiently fine, wear and tear on the molding machine can be sufficiently prevented, and a molded product with a smooth surface can be obtained.

(C) Produce a liquid or powder coating material by mixing a suitable liquid or thermoplastic paint with fine powder. At this time, the above (a
Similar to item ), mixing can be carried out easily, quickly and uniformly, and a coating material that does not clog the spray gun can be obtained.

These products can be used, for example, to provide car seats, steering wheels, wall materials, furniture, and other various uses with characteristics such as the texture of natural leather.

[Another example]

Next, another example will be shown.

Using tanned leather as a raw material has advantages such as easier pulverization and improved bacterial resistance of the product, but leather that has not been tanned but has undergone some or all pretreatment or It is also possible to use untreated skin as raw material.

The drying process before the pulverization process can be omitted, for example, when the leather pieces after heat treatment have a sufficiently low moisture content, or when the moisture content becomes sufficiently low due to natural drying during storage.

The type of product to be made from the leather fine powder obtained through the pulverization treatment and subsequent treatment can be appropriately selected. For example, it is possible to make a product by adhering the fine powder to a film, cloth, paper, or other sheet.

The surface of the molded product can be suitably finished by, for example, embossing, enameling, surface grinding, etc.

It is desirable to degrease the leather in order to improve the grinding efficiency and prevent color change of the product, and degrease the leather at an appropriate time, such as before or after heat treatment, or before or after fine grinding. Apply to leather. The degreasing treatment is carried out by immersing the leather in a solvent for fats and oils such as benzine, methyl chloride, methyl acetone, and ethyl acetate, or in warm water.

Particularly preferably, a strip of leather is immersed in a heated solvent for degreasing and ultrasonic waves are applied to the strip of leather,
To efficiently perform heat treatment and degreasing treatment simultaneously.

The use and form of use of the natural leather fine powder, synthetic leather composition, coating material, and synthetic leather molded product according to the present invention are not limited.

[Brief explanation of the drawing]

The drawing is a flow sheet showing an embodiment of the invention.

Claims (1)

[Scope of Claims] 1. Natural leather is cut into strips, and the leather strips are heat-treated to loosen the entanglements of collagen, which is the main component of leather, and the leather strips have the collagen loosened. A method for producing fine leather powder by pulverizing a natural leather powder, the method comprising applying ultrasonic waves to the leather strips during heat treatment of the leather strips. 2. The method for producing fine powder of natural leather according to claim 1, wherein the heat treatment of the leather strips is performed by steam heating. 3. The method for producing fine powder of natural leather according to claim 1, wherein the heating of the leather strips is carried out by immersing them in heated water. 4. The method for producing fine powder of natural leather according to claim 1, wherein the heating of the leather strips is carried out by immersing the leather in a heated solvent for degreasing the leather. 5. Heat-treat strips of natural leather under ultrasonic waves,
Fine natural leather powder is made by disentangling collagen, the main component of leather, and then finely pulverizing the disentangled pieces of leather. 6. Heat treating strips of natural leather under ultrasonic waves,
This synthetic leather composition is a mixture of natural leather fine powder, which is made by disentangling collagen, which is the main component of leather, and finely pulverizing the disentangled leather pieces, and a resin. 7. Heat treating strips of natural leather under ultrasonic waves,
A coating material that is a mixture of fine natural leather powder, which is made by disentangling collagen, the main component of leather, and finely pulverizing the disentangled pieces of leather, and paint. 8. Heat treating strips of natural leather under ultrasonic waves,
Synthetic leather molding is made by molding a mixture of natural leather fine powder, which is made by disentangling collagen, the main component of leather, and finely pulverizing the disentangled leather pieces, and a resin. Goods.