JPS63286500A - 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 (Industrial Application Field) This invention is a method of processing natural leather into fine powder to obtain a leather-like molded product or a leather-like formed film having characteristics similar to natural leather. More specifically, the leather powder that has been crushed and provided does not become intertwined with each other and become disassembled (like unraveling cotton), but instead exhibits an independent "grain" shape. It is an object of the present invention to provide a leather powder that does not cause the disadvantage 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 a 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 the apparent specific gravity of the leather powder used fall within the range of 0.38 to 0.50 (g/cc), the pulverized leather vinegar powder can be mixed with each other. This prevents tangles and makes 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 ultrafine leather powder, such as one that is sorted with a 0-mesh sieve and classified with an air separator, and the amount of leather powder that is smaller than 40 microns is 70% by weight or more, leather powder is Mutual entanglement no longer occurs.

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

It can be used to form sheets, films, etc., it can be used to form coatings or transfer films, or it can be mixed into paints and used to form paint films. It has the feature that it does not get entangled with other materials and can be evenly scattered over resin fabrics, 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 above appearance has a specific gravity of 0.38 to 0.50.
(g/cc) when used with resin or paint, the leather powder may turn yellowish brown, resulting in unexpected color development or discoloration on the surface of the molded product or formed coating. found.

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 articles, etc. according to the present invention is a method for forming leather powder that does not cause discoloration while retaining the advantages of the conventional leather powder described above. It is intended to provide services.

First, shaving waste that has been subjected to chromium treatment is placed in a processing chamber, and steam is supplied to the leather placed in the processing chamber at a temperature in the range of approximately 100 to 119°C. The steam heating sufficiently swells the leather, loosens the entanglements between the collagen fibers, and causes the tissue to shrink.

The leather heated and swollen in this way is
Wash with boiling water around 00℃. This hot water washing may be done by immersing the leather in boiling water, or by pouring boiling water onto the treated leather in the processing chamber while stirring, or by any method suitable for eluting the oils and fats in the leather.

The leather that has been treated to dissolve the harmful oils and fats is dried again,
By pulverizing this with a pulverizer such as Fine Victory Mill, it was possible to obtain a fine powdered leather powder that did not tangle and did not discolor.

(Function, effect) In the leather powder produced by the above method, the 2 to 10% oil content normally contained in leather powder is eluted to a large extent, and the remaining oil content is extremely weak. found.

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, by removing the oils and fats from the leather while the leather is in a swollen state using the above method, the oils and fats can be extracted naturally and to the desired extent within an extremely short period of time. It was found that there was no wear and tear on the leather during removal.

In addition, in the above method, since the leather does not contain oil or fat, it can be easily and reliably crushed, and it was possible to obtain extremely fine powdered leather powder.

As a result, the above leather powder was sorted through a 40-mesh sieve and dried to about 3% by weight, with an apparent specific gravity of 0.30 to 0.5.
The leather powder was in the range of 0 (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 by the above-mentioned molding method does not discolor the mixed leather powder, reliably prevents discoloration, blurring, etc. on the surface of the molded product or the painted surface, and has a texture that is closer to that of natural leather. It has the advantage of being

(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 was twisted into an elongated kelp shape, which 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 80% by weight (wet basis) is put into this processing chamber l, and the chamber pressure is 1 K.
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 .

It was observed that the leather extracted by steam heating in this manner had an increased moisture content in the range of 5 to 10% by weight, depending on the type of leather, properties, etc. Moreover, supply steam A
The collagen fibers constituting the leather shrink as a result of being subjected to heating swelling due to the Ilivf1m leather, evaporation from the Ilivf1m leather, and liquefaction and moisture accompanying condensation over time.

It was also said that the connection was loose.

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 heated and swollen with steam in this way is
The leather is treated with hot water at around 00°C to elute the oils and fats contained in the leather. The oils and fats contained in the leather can be leached out by immersing the leather, which is said to be in a moist state, in hot water and stirring, or by similarly massaging it in hot water, or by pouring boiling water into a basket containing the leather. By various methods such as pouring.

This hot water washing process is used to dissolve as much of the oil and fat contained in the leather as possible, but it is not necessarily necessary to elute the entire amount of fat contained in the leather. It suffices if the oil and fat content is removed within the range that can be prevented.

In addition, most of the fat content, which is usually around 8.5% for sheepskin, 6.8% for steer skin, and 10.5% for horsehide, was eluted by the above hot water washing treatment.

The leather that has been subjected to the above steam heat treatment and hot water washing treatment is removed by stopping the steam supply to the processing chamber 1 into which the leather is placed, and supplying the jacket 4 with steam B (approximately 1 Kg/a/valve). 5) to heat and dry the leather in the processing chamber.

The leather that has been subjected to the fat elution 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, s,), empty/actual operation is 17.2720
(ampere) with the slit half open. As another example, the number of revolutions is 7800 (r, p, a,) and the empty/
The actual slow rotation was 15.8/20 (ampere) and the slit was fully opened.

The leather powder pulverized by the above-mentioned pulverization process was sorted using a 40-mesh sieve to make it suitable for mixing with wood 11F1, etc., to produce leather powder with the following particle size.

40-60 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~BO mesh 5.7% 60~80 mesh 7.0% 80~100 mesh 5.7%100~150
mesh 38.4% 150-200 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 in the form of "granules" that exist independently without intertwining with each other. It is at the point.

1 In this specification, the appearance refers to the loose specific gravity, and the appearance refers to the specific gravity.
After putting it into a 0cc container, it was cut into pieces and weighed using a top balance, and the result was expressed as the weight of 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, if the above leather powder needs to be included in a thin film for painting, coating, or laminated film, it is classified into 8 parts according to true specific gravity using an air classifier to create finer leather powder. -I did.

This classification will be explained with reference to FIGS. 2 and 3. 11
is a feeder into which the leather powder is input and sequentially sent to an air classifier (micro separator) 12. This air classifier 12 has a rotor 12a, and the leather powder supplied from the input port 12b is fed into the air classifier 12. The powder is separated and suctioned based on its true specific gravity, and sent into a backfirer 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 eye a.

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

In this device, the rotation speed of the rotor 12 is set to 800 (r
, p, m,) Secondary air volume is 4.0 m″/min, dust collection air volume is 21
m''/min, and when 5 kg of leather powder was added, the result was 2.0
5 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 has no mutual entanglement as in the previous example, and each individual leather powder exists independently, and does not become fluff-like or aggregate into lumps. It has been found. Although this leather powder was in the form of an extremely fine powder, it had no fibrous parts and 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.
Moreover, it was found that even if it was mixed into a paint (including a coating liquid), it was uniformly dispersed in the paint because it did not become entangled in the form of fluff. Similarly, if it gets mixed into the molding material of a film that is applied onto a release paper and then transferred onto cloth, paper, resin film, leather, etc.
It was found that this film was uniformly dispersed in the molding coating liquid.

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 as a percentage of - within each particle size range. It is. (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 48 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 can be done in the process of heating the leather with steam, or in the process of crushing the leather into leather powder, and then again under humidified conditions after being made into leather powder. The most suitable method will be 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 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 90 parts by weight Stabilizer 3 parts by weight Leather powder 80 to 200 parts by weight (2) Formation of paint film Two parts containing 20 to 50% solid content Type reactive urethane elastomer solution 100 parts by weight Crosslinking agent 5~
1 part by weight Leather powder 5 to 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 45 parts by weight
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 those of natural leather. It has been found that the properties are similar to those of acids and, moreover, no discoloration occurs.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a leather steam heating device, Figure 2 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 of leather powder, with the horizontal axis showing grains. The diameter is shown in microns and the distribution amount is shown in weight% on the vertical axis. Figure 5 shows a symmetrical garment with mesh and micron. In the figure, 1...processing chamber, 2...valve, 3...stirring means,
4...Jacket, 5...Valve, ll...Feeder, 12...Air classifier, 13...Turbo fan, 14...Back filter tank.

Claims (1)

[Claims] The leather is subjected to prescribed heating and swelling treatment using the supplied steam, and the treated leather is washed with hot water to elute the oils and fats in the treated leather, and then forcibly dried and pulverized to form fine leather powder. A method for forming leather powder characterized by: