JPS63286499A - Method for molding leather powder - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Field of Industrial Application) This invention is a method for producing a leather powder for obtaining a leather-like molded product or a leather-like formed film having characteristics similar to natural leather by turning natural leather into fine powder. More specifically, the leather powder that has been crushed does not intertwine with each other and form a disassembled shape (similar to unraveled cotton78), but instead has a unique "grain" shape. The present invention aims to provide a leather powder which exhibits the following characteristics and is free from the disadvantages of color development or discoloration that occurs in a formed coating film or a resin molded product due to discoloration of the leather powder mixed in the paint or resin.

PRIOR ART The applicant has already disclosed in a number of patent applications a method for grinding leather, a method for utilizing this ground leather powder and an improvement in the properties of the leather powder provided by the grinding.

Among these series of applications, the present applicant has continued to develop leather powder having the following properties, and has succeeded in commercializing it.

In order to eliminate the inconveniences caused by leather powder, which is produced only by mechanical and physical crushing such as a hammer type as a means of forming leather powder, the leather is sufficiently swollen in steam before being crushed. The apparent specific gravity of the leather is increased by a method such as crushing the leather after weakening the tissue due to this swelling.

In this way, by increasing the apparent specific gravity and making sure that the apparent specific gravity of the leather powder used is within the range of 0.38 to 0.50 (g/cc), it is possible to prevent the pulverized leather powder from entangling with each other. This made it possible to mix with resin fabrics, etc.

As a result, the apparent appearance of leather powder with a specific gravity of 0.38 to 0.50 (g/cc) when the moisture content was 3% by weight or less was 4%.
Even in the case of unique ultra-fine powder leather powder, such as one that is sorted with a 0 mesh sieve and further classified with an air separator, the proportion of leather powder particles smaller than 40 microns is 70% or more by weight. Powders no longer get entangled with each other.

Therefore, this leather powder is used to make various resin molded products.

It can be used to form sheets, films, films, etc., it can be used to form coatings or transfer films, or it can be mixed into paints and used to form painted films, and in either of these cases, mixed leather can be used. It had the feature that the powder did not get tangled in a disassembled pattern and was evenly scattered over the resin fabric, etc.

Also, in this way, it is evenly mixed into resin fabrics, paints, etc.
In addition, it has sufficient lubricity, so it has the advantage that the properties of mixed leather powder can be fully imparted to molded resin products, films, sheets, coated or transferred coatings, or painted coatings. was.

However, the appearance of the story has a specific gravity of 0.38 to 0.50.
It has been found that when leather powder (g7cc) is used with resin or paint, the leather powder may change color to yellowish brown, resulting in unexpected color development or discoloration on the surface of molded products and formed coatings. .

Such inconveniences occur particularly when the molded product is of a white or thin plain color, and countermeasures have been required. It has also been pointed out that the surface of a molded article or painted film that has undergone such discoloration tends to feel slightly sticky to the touch.

(Objects and structure of the present invention) The method for forming leather powder used for leather-like molded products, etc. according to the present invention is a method for forming leather powder that does not cause the discoloration described above while retaining the advantages of the conventional leather powder described above. It is intended to provide services.

First, chromium-treated shaving waste, etc. is treated with a solvent that has oily elution properties such as benzene (industrial gasoline No. 1), methyl chloride, methyl acetone, and ethyl acetate to remove oily substances from the leather. Measure.

The elution of such oils and fats does not necessarily require the elution of all the oils and fats contained in the leather, and it is sufficient that the leather powder is eluted to the extent that the leather powder is not discolored by these oils and fats.

Next, several pieces of shaving waste that have been subjected to oil and fat elution treatment are placed in the processing chamber, and steam is supplied to the leather placed in the processing chamber at a temperature in the approximate range of 100 to 119°C. Then, the leather is sufficiently swollen by this steam heating, the collagen fibers are loosened from each other, and the tissue is caused to shrink.

The leather that has been subjected to visible oil and fat dissolution treatment and steam heat treatment is dried again and then crushed using a grinder such as Fine Victory Mill to produce a fine powder that does not tangle and does not discolor. No leather powder could be obtained.

(Function, Effect) In the leather powder produced by the above method, it was found that the 2 to 10% of oil and fat normally contained in leather powder was eluted to a large extent, and the residual oil and fat content was extremely weak. did.

The leather powder produced by this method is completely granular, and has the characteristic that cilia do not form on the circumference of the leather powder, and the leather powder itself does not become fibrous. There was found.

In addition, in the above method, since the leather does not contain oil or fat, the steam heat treatment achieves the desired purpose in a short time, and the grinding is easy and reliable, resulting in ultrafine leather powder. We were able to.

As a result, the leather powder was sorted through a 40-mesh sieve and dried to about 3% by weight, with an apparent specific gravity of 0.30-0.
The leather powder was in the range of 50 (g/cc).

From the above points, the leather powder produced by the above method is
It has the characteristic that the leather powder is evenly dispersed in the molded resin fabric or paint without intertwining with each other, and has the feature that it does not cause roughness on the surface of the molded resin product or painted film.

In addition, since the leather powder itself has good lubricity, there is less resistance during extrusion of the dough, and there is no possibility of waving on the surface of the molded product or causing problems such as warping or tearing on the film surface.

In particular, the leather powder produced using the above molding method does not cause any discoloration due to the mixed leather vinegar powder, reliably prevents discoloration or blurring on the surface of the molded product or the painted surface, and provides a texture that is closer to that of natural leather. It has the following advantages.

(Example) Typical embodiments of the present invention will be described below with reference to the attached drawings. In this example, leather scraps are mainly used to form leather powder, and shaving scraps treated by Chrome Co. was used.

This shaving waste usually has a fat content of 8.5% for sheepskin, 8.8% for steer skin, and 10.5% for horsehide.
Industrial gasoline No. 1) Treated with various solvents such as methyl chloride, methyl acetone, and ethyl acetate to dissolve as much fat as possible from the leather. (It is not necessarily necessary to elute the entire amount of fat.) The solvent used should be selected depending on the type of leather.
Any solvent may be used as long as it does not damage the leather and can effectively dissolve the fat content, and various other solvents may be used without being limited to those mentioned above. The leather such as shaving waste from which the oil and fat content had been eluted in this manner was cut into appropriate lengths with a cutter mill and placed into the processing chamber 1 shown in FIG.

800 kg of leather having a moisture content of 50 to 60% by weight (wet basis) was put into this processing chamber l, and the chamber pressure was adjusted to IK.
Processing chamber 1 while adjusting valve 2 so that it is around g/a/
Steam A is supplied to the chamber, and the temperature in the processing chamber is 100℃ to 119℃.
In this state, the leather was stirred using the stirring means 3 for 30 minutes.

In addition, this steam heat treatment has an apparent specific gravity of 0.38 to 0.50 (g/cc) of the leather powder produced by this method.
This can be continued until .

The leather extracted by steam heating in this way contains water and water in a range of 5 to 10% by weight, depending on the type and properties of the leather.
It was found that the proportion was increased. Furthermore, the collagen fibers constituting the leather are caused to shrink as a result of being subjected to heating and swelling by the supplied steam A, evaporation from the swollen leather, and liquefaction and moisture accompanying condensation over time.

It was also said that the connection was loose. In addition, by performing the above-mentioned oil and fat elution treatment, even if the leather powder is treated with steam heating for a short time, the apparent specific gravity of 0.30 to 0.50 (g/cc) will be It could be made into powder.

In addition, during the above steam heating, the outer periphery of the processing chamber is covered with a jacket 4.
In some cases, heating from outside the processing chamber is simultaneously performed by separately supplying processing heating steam to this jacket 4.

The leather that has been subjected to the steam heat treatment as described above is treated by stopping the steam supply to the processing chamber 1 into which the leather is placed, and operating the valve 5 so that the steam B (approximately 1 kg/al/l) is supplied to the jacket 4. ) is supplied and the leather in the processing chamber is heated and dried.

The leather that has been subjected to the fat elution treatment and the steam treatment is then dried and pulverized using a pulverizer such as a Fine Victory Mill so that the moisture content is usually within 3% by weight.

This Fine Victory Mill operates at a rotation speed of 7000
(r, p, m,), empty/actual operation is 17.2/20
(ampere) with the slit half open. As another example, the rotation speed is 7800 (r, p, s,), and the empty/
Actual operation was carried out with the slit fully open at 15.8720 (ampere).

The leather powder pulverized by the above-mentioned pulverization process was sorted using a 40-mesh sieve to make it suitable for mixing with resin, etc., to produce leather powder with the following particle size.

40-80 mesh 2°8% 60-80 mesh 9.7% 80-100 mesh 9.7%100-150
mesh 25.7% 150-200 mesh
13.9% 200-300 mesh 33.7%
300 mesh to 4.5% Furthermore, similar crushed leather powders were colored in the steam heating process to produce leather powders with the following particle sizes.

40-60 mesh 5.7% 60-80 mesh 7.0% 80-100 mesh 5.7%too-150
Metshu 39.4%! 50-200 mesh
30.0%200-300 mesh 12.2%
Leather powder with a particle size of 300 to 0% is most suitable for molding with various resin materials, and is suitable for any molding such as calender roll, extrusion, injection, etc.

The apparent specific gravity of this leather powder is 0.30g/cc ~
It was set to be between 0.50 g/cc. (By removing the oil and fat content of leather powder, the apparent specific gravity is 0.30g/c.
Even with the leather powder (c), mutual entanglement could be prevented. ) The reason why this apparent specific gravity is significantly higher than that of previous leather powders is that the leather powder no longer has fibrous parts (1) The individual leather powders are ``grained'' that exist independently without intertwining with each other. The point is that

In this specification, the appearance refers to the specific gravity, and the appearance refers to the specific gravity.The sieve is vibrated to pass the leather powder through the chute.
After putting it into containers 0c and c, it was cut into pieces and weighed on a top balance, and the result was expressed as the weight of the leather powder divided by 100.

Further, the relationship between mesh and micron particle shape in this specification is as shown in the table of FIG.

Next, when it is necessary to incorporate the above leather powder into a thin film for painting, coating, or laminating film, it is classified by true specific gravity using an air classifier to create a finer leather powder. did.

This classification will be explained with reference to FIGS. 2 and 3. 11
is a feeder, which inputs the leather powder and sequentially sends it to the air classifier 1 (micro separator) 12. This air classifier 12 has a rotor 12a, and the leather powder is supplied from the input port 12b. The leather powder is separated and suctioned based on its true specific gravity, and sent into a back filter tank 14 by a turbo fan 13 for classification. The classified coarse powder was taken out from the rotary valve 12c, and the fine powder was taken out from the rotary valve 14a.

Note that 12d indicates an intake port for secondary air, and 12e indicates an outlet for classified fine powder.

In this device, the rotational speed of the rotor 12 is set to Boo(r
, p, m,) Secondary air volume is 4.0 go/min, dust collection wind is 21 m
''/min, and when 5 kg of leather powder was added, the result was 2.05
Kg of fine powder was obtained.

As shown in the graph of FIG. 4, the particle size distribution of this classified leather powder has an average particle size of 24.5 microns, most of which are within 50 microns. Further, the apparent specific gravity of the classified leather powder was set to be between 0.30 and 0.50 g/cc.

The fine leather powder produced in this way does not intertwine with each other as in the previous example, and each individual leather powder exists independently, so it does not become flocculent or aggregate into lumps. found. Although this leather powder was in the form of an extremely fine powder, there were no m#I-shaped parts at all, and there were no intertwined parts.

In addition, the particle size of this classified leather powder is generally within 100 microns, as shown in the graph of Figure 4, and the majority is within 40 microns, and furthermore, it does not become tangled in a flocculent manner at all. Paint (
It has been found that even when mixed in paint (including coating liquid), it is uniformly dispersed in the paint. Similarly, if it is mixed into the molding material of a film that is applied on release paper and then transferred onto cloth, paper, resin film, leather, etc., it will be uniformly mixed into the molding coating liquid of this film. It turned out to be distributed.

The graph in Figure 4 shows the fine powder classified by a classifier, suspended in methyl alcohol, measured with a Coulter counter, and then expressed in weight percent within each particle size range. . (The vertical axis shows the distribution amount in weight percent, and the horizontal axis shows the particle size in microns.) According to this, leather powder finer than 40 microns is 78.7
Although it is clear that the particle size is 40% by weight, it is possible to mix leather powder with a slightly larger particle size than this when mixed with the above paint, etc., and according to the applicant's experiments, it is possible to mix leather powder with a particle size slightly larger than 40 microns. It has been found that good results can be obtained if the fine leather powder is 70% by weight or more of the total amount and if the leather powder larger than 150 microns is effectively cut.

In addition, the elution of oil and fat content in the above does not necessarily require elution of all the fat content in the leather, and the content of fat content must be eluted within a range that does not cause discoloration of these leather powders. It means.

The leather powder molded above is subjected to dyeing treatment as necessary, and this dyeing treatment is performed using an appropriate dye and dyeing method depending on the properties of the leather powder.

These dyeings are done in the process of heating the leather with steam, or in the process of grinding it into leather powder, and then again under humidified conditions after being made into leather powder, depending on the type of each plant. , the optimal method is adopted.

The leather powder with the above structure has a more pronounced effect when molded with synthetic resin, unlike the conventional leather powder that was simply finely powdered, and it can also be mixed into paint to form a coating material.
It was particularly effective when mixed with synthetic bark liquid in the form of a solution, emulsion, or solution (containing a liquid polymer) and used to create a coating material or a transfer film for laminate.

In addition, there will be no discoloration on the surface of resin molded products, sheets, films molded by mixing these leather powders, or painted films or transfer films formed, and it will not cause any discoloration on the surface of the resin molded products, sheets, films, etc. that are molded by mixing these leather powders. The leather powder was considered to be ideal for molding or finishing the surface of these products.

Furthermore, by reducing the fat content in the leather powder, the moisture absorption function of the leather powder is enhanced, and the resin molded products, sheets, films, and other products mixed with these leather powders have a good texture without sweaty feeling. It has the characteristics of painted films or transfer films.

Some examples in which the leather powder was actually used are shown below for reference.

(1) Molding of soft vinyl chloride sheet Vinyl chloride resin 100 parts by weight Plasticizer 80 parts by weight Stabilizer 3 parts by weight Leather powder 80 to 200 parts by weight (2) Two parts by weight containing 20 to 50% solids for forming an IT coating film Liquid reactive urethane elastomer solution 100 parts by weight Crosslinking agent 5~
10 parts by weight Leather powder 5-45 parts by weight (3
) Formation of transfer film Two-component reactive urethane elastomer solution containing 20 to 50% solids 100 parts by weight Crosslinking agent 5 to
10 parts by weight Leather powder In any of the examples of 10 to 70 parts by weight or more, the leather powder is evenly mixed into the resin fabric or paint, creating the desired leather-like surface, and the surface characteristics are similar to that of natural leather. It was found that the characteristics were similar to those of the other materials, and there was no discoloration at all.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a leather steam heating device, MS2 diagram is a schematic diagram of a classifier, Figure 3 is a schematic diagram of a classifier, and Figure 4 is a graph showing the distribution amount of leather powder, with the horizontal axis being the particle size. is shown in microns, and the distribution amount is shown in weight% on the vertical axis. Figure 5 is a symmetry table between mesh and micron. In the figure, 1...processing chamber, 2...valve, 3...stirring means,
4... Jacket, 5... Valve, 11... Feeder, 12... Air classifier, 13... Turbo fan, 14... Back filter tank.

Claims (1)

[Claims] Molding of leather powder characterized by eluting the oils and fats contained in the leather with a solvent, heating and swelling in supplied steam, and then forcibly drying and pulverizing to obtain fine leather powder. Method.