JPH084756B2 - How to crush leather - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Use) The natural leather material of the present invention is pulverized into a fine powder, and the pulverized leather powder is used to form sheets, films or various molded products similar to those of natural leather. It is related to the pulverization of leather, which was a problem at the time, more specifically, steaming leather under specific conditions and performing pulverization processing in the state where the leather-specific viscosity, viscoelasticity, etc. are removed. The purpose is to provide leather powder with a uniform particle size and no cilia.

(Prior Art and Its Deficiencies) The applicant of the present invention is Japanese Patent Application No. 61-102611 (Japanese Patent Application Laid-Open No. 62-258000).
No.), No. 102612, No. 102613, etc., we are continuing to develop leather-like molded products made of leather powder as an aggregate.

However, the development of such a leather-like molded product has some drawbacks, which have not been sufficiently solved.

One of them is that the leather powder to be mixed with the resin is not too large or too small to be compatible with the resin material, and the leather powders tend to be entangled with each other to become cotton-like or lumpy. Secondly, it has been considered extremely difficult to crush the leather into a uniform particle size depending on the properties of the leather, and particularly to produce the leather powder so as not to generate cilia in the molded leather powder.

First, when considering leather powder from the viewpoint of resin molded products, the leather powder used for molding has a particle size smaller than 150 mesh 54.7% 100 to 150 mesh 18.4% 60 to 100 mesh Resin molding was particularly good when the particle size distribution was 15.5% 30-60 mesh and 11.4%, and the condition was that the leather powder used had no cilia.

The problem of the grain shape of the leather powder on such resin molding is that if the leather powder used is larger than the above particle size, the mixture of the leather powder and the resin material will be poor, and the leather powder mixed on the surface It had the inconvenience of causing a rough skin phenomenon.
In addition, when the particle size of the leather powder is large as described above, the smoothness of the leather powder itself is poor, and it is not evenly scattered in the resin material, and a lump portion is often formed in the molded resin in a condensed state. In addition, it often causes a large flow resistance of the molding material during resin molding, which is a cause of pulsation at the time of molding, resulting in a factor of molding distortion in many cases.

On the other hand, when the leather powder used as an aggregate is used in a finer range than the particle size in the above range, the leather powders have the characteristic of being entangled in a cotton shape, and the smoothness of the leather powder is the above. Like the case, it had a tendency to be disturbed. That is, it was confirmed that the finer the leather powder to be used, the less the slipperiness of the leather powder itself, and the finer cotton lumps, resulting in the molding similar to that of the above-described leather powder having an excessively large diameter. Had the inconvenience.

Then, as a technical problem in molding the leather powder, especially the crushing device and the crushing conditions and the crushing conditions depending on the respective target leather powder such as the crushing of the cowhide with a strong collagen fiber or the crushing of the pigskin rich in oil and fat. Need to change,
It has been difficult to provide a leather powder having a particle size, a particle size and properties suitable for the purpose.

For example, cowhide is as thick as 3 to 12 mm, and it is difficult to crush it because 80% of the total thickness is the part where the collagen fiber bundles are intimately entangled. When this is crushed by beating, fine powder and lumps are formed. Since it became powder and each had a cilia part, it could hardly be used.

Moreover, since most of the net-like layer of pig skin is occupied by fat cells, when this is crushed with a cutting blade, the crushing and crushing ability is lost in a relatively short time, making it unsuitable for mass production of leather powder. It had been.

(Object and Structure of the Present Invention) The method for crushing leather according to the present invention was developed by many improvements and researches by the applicant of the present invention. The leather powder has a uniform particle size, and each leather powder does not have a cilia part.

That is, the Applicant firstly confirmed that the grain size of the crushed leather powder is within the above-mentioned ideal grain size distribution range, and that none of the molded leather powder has a cilia part. In consideration of the fact that it is possible to crush with the same equipment and under the same conditions for any type of leather such as cowhide, pigskin, or sheepskin, it is easy to crush and suitable for mass production. , Devised the following method.

That is, the crushing method of leather according to the present invention, first, a leather material,
Particularly, blue floor leather, shaving waste leather, etc. are cut into a crushing machine or a crushing machine to make leather pieces or powdery or fluffy leather, and this leather material is put into the processing chamber. And, steam is always supplied to this processing chamber, and the wall of the processing chamber is 100 ° C.
The leather material that has been heated and put in as described above is appropriately agitated.

When the leather material is treated in such a state, the leather material in the treatment chamber is swollen in a sufficiently heated state and contacts the chamber wall. The leather material contacted with such a chamber wall is further heated, and finally transitions to a transpiration state, and with this transition (that is,
The temperature was suddenly lowered (by the required heat of vaporization), and it was separated from the chamber wall by a stirring operation, resulting in further reduction of the amount of heat retained.

Therefore, the leather material was not boiled in spite of being heated in a sufficiently swollen state, and was continuously subjected to a temporal and thermal change of collagen protein.

After sufficiently changing the physical properties of the collagen fiber in this way, remove the leather material from the processing chamber and remove it by 4%.
Within, ideally within 3%, the leather pieces were crushed in this dry state. This crushing device may be an appropriate device such as a ball mill depending on the material and shape of the leather material, and it is usually a stepwise use of mills suitable for fine powder in accordance with the crushed particle size. By the method, it was possible to efficiently obtain leather powder having a uniform particle size. In particular, the leather material that has undergone the above pretreatment process is brittle against fracture, has no viscoelasticity, and is free from oils and fats, and can be crushed to an appropriate particle size within an extremely short time. Moreover, the crushed leather powder has a uniform particle size and has no cilia part.

(Actions and Effects) It has been confirmed that the method for crushing leather according to the present invention has the following actions and effects due to the characteristic constitution of the removal.

(1) The formation of leather powder is premised on the step of cutting leather or steam heating a crushed leather material, and the collagen protein constituting the leather is sufficiently swollen in this steam heating step, and its composition structure changes with time. As a result of repeated heat-repetition of the solid-solution state, the close cohesion between tissues is relaxed, and the oil and fat existing between collagen fiber bundles are removed, resulting in a more pure collagen protein assembly. It is made into a body, and part of glue and other glue is eluted.

It has been found that when the leather material is dried until the water content is 2.3 to 3% in such a state, the leather material is crushed by a relatively small impact.

Therefore, when this dried leather material was gradually put into a ball mill, colloid mill, etc., crushed, and screened with a 30-mesh screen, it was finer than 150 mesh 54.7% 100-150 mesh 18.4% 60- It was possible to obtain leather powder having a particle size distribution of 100 mesh 15.5% 30 to 60 mesh 11.4%.

(2) Further, even in the step of pulverizing the leather material into powder, the leather material is effectively made into a fine granular powder, and the crushed powder has a ciliated part, or the powder itself becomes fibrous. A leather powder having good slipperiness was molded and provided.

(3) Further, the viscoelasticity of the leather tissue, in particular, the viscoelasticity of collagen fibers and the loss of oil and fat cause a structural disintegration of the leather material, and the leather material can be efficiently granulated by a simple device. It has the feature that the leather tissue does not become loose and entangled with the crushing blade.

(4) In addition, the glue or oil and fat with weak tissue strength contained in the collagen fiber is removed to obtain a purer leather powder containing only collagen protein and the particle size is uniform, and the cilia part is also present. It has a good compatibility with the resin material to be kneaded because it does not have, and has the characteristic that it is smoothly mixed into the resin material and mixes evenly, and the mixed leather powders are entangled with each other during resin molding The inconvenience disappeared.

(5) Further, since the leather powder mixed in the resin molding does not have a cilia part, the contact resistance at the time of molding such as extrusion and injection is low, and the composition of the molded product is not dense and dense due to the pulsation generated at the time of molding. There are few, and it has the feature that there is almost no distortion during or after molding.

(6) Furthermore, since the leather powder to be mixed is a purer collagen protein, it has a function of imparting a certain fluidity to the molding resin and further uniformizing the movement of the resin material itself. In addition to having the property of avoiding densification of the composition of the molded product more than usual resin molding, this mixed leather powder functions to individually cut off the residual stress generated in the molded resin fabric, resulting in It was possible to provide molded products with less distortion.

(7) Further, the leather powder mixed in the resin material has a uniform particle size, and as a result of being evenly distributed in the molding material, it is accompanied by the swelling of the leather powder in the resin material. It has the advantage that the molded product does not warp and warpage due to temperature change and humidity change of the molded product does not occur.

(Example) Hereinafter, an example of a method for molding a leather-like molded article according to the present invention will be described in detail.

Firstly, the leather used is mainly chrome tanned cowhide, pig skin, sheep skin, etc., and tannin tanned leather is used in part.

Since the collagen fiber of the cowhide in the conventional method was tough, its crushing, in the process of pulverizing, the problem of uneven particle size, and the problem of cilia generation, and also in pig skin, in the leather It had a problem of poor grinding due to oil and fat,
In the following examples, whether cowhide or pig skin,
It has the advantage that it can be processed uniformly regardless of its type.

In addition, the use of tanned leather is to treat the leather processing and to prevent the development and decay of leather powder in the state of being incorporated in the molded product, and basically from that purpose, chrome tanning is used. A treated floor skin or shaving layer is utilized.

In addition, there is also a case where a floor skin or floor skin waste as a back lining material before chrome tanning is used and this is subjected to a chrome treatment.

The leather material is cut into pieces, powder or fluff so as to be suitable for the following treatment by a cutting machine, and the leather material is put into a steaming device and steam-heated for a predetermined time.

By the way, the steam heating device A has a substantially cylindrical shape, has a double wall including an inner wall 1 and an outer wall 2, and a gap 3 between the double walls serves as a flow path for one of the steams a. Is the processing chamber 4. Then, stirring blades 5 and 5 are provided on the rotating shaft 6 in the processing chamber 4 so that the leather material B put into the processing chamber 4 is stirred. Further, another water vapor b is introduced into the residual space of the processing chamber 4, and these water vapor b
The liquefied water liquid of is drained from the drain 7.

Into such a steam heating device A, a leather material B which usually contains 50% to 67% of water is put, and the processing chamber 4 and the gap 3 are inserted.
At 130 ° C., 2 kg / cm ² of water vapor a and b are supplied.

First, the leather material B is swollen by the supply of the water vapor b and absorbs water to a saturated state. Then, the water content of the leather material B changes with the temperature change of the leather material B with time,
It was found to maintain a saturated state within that temperature range.

When steam a is sent to the gap 3 in such a state, the inner wall 1
Is heated and moves the leather material B in contact with it to a high temperature range to increase the water content, and finally reach the vaporization point, vaporize and evaporate, and rapidly reduce the temperature.
Further, the leather strip B released into the air from the inner wall of the processing chamber 4 due to the stirring by the stirring blade 5 also rapidly loses the heat source,
Both were found to release the water content (in the condensed state) beyond the saturated state.

Therefore, the leather material thrown into the processing chamber 4 is affected by absorption of water vapor due to heating and condensation and water release due to temperature decrease, which causes a large change in the physical properties of protein collagen. I was told that.

In addition, when the temperature of the leather material B in the above-mentioned device A was measured, it was found that the variation was within the range of the attached graph.

In these actual operations, this steam heating ideally changes the temperature in the steaming device within a certain range by further heating the leather material put in the steam from the outside while stirring. Yes, the properties of the leather being put in,
The shape and quantity determine this ideal value.

In the above device, the leather material put into the steam heating device undergoes a thermal change with time in a sufficiently swollen state, causing a change in the protein composition of the collagen protein and at the same time the oil and fat content and the water content contained in the collagen fiber. The highly adhesive glue was removed, resulting in a purer collagen protein that was completely swollen for a long time.

Such swelling, drying the heated leather material, ideally
It was rapidly dried to a water content of 2.3% to 4% (weight ratio) and put into a crusher. This crusher is an appropriate device such as a ball mill depending on the properties and shape of the leather material.Usually, a mill suitable for fine powder is used step by step in accordance with the crushed particle size to efficiently and efficiently. Moreover, leather powder having a uniform particle size could be obtained.

In particular, the leather material that has undergone the above pretreatment step is brittle against fracture, has no viscoelasticity, and can be crushed to an appropriate particle size in an extremely short time because the oil and fat content has been removed, Moreover, the crushed leather powder has a uniform particle size and has no cilia part.

By passing the crushed leather powder through a 30-mesh sieve, finer than 150 mesh 54.7% 100-150 mesh 18.4% 60-100 mesh 15.5% 30-60 mesh 11.4% ideal It was possible to obtain a leather powder having a different particle size distribution.

15-60% of leather powder molded by the above process, 40-85% (both by weight) of resin compound which is a thermoplastic resin such as vinyl chloride added with plasticizer, stabilizer, etc. However, in this molding, a foamed molded product may be molded by separately mixing an aggregate or a modifying agent such as calcium carbonate powder and gelatin, and mixing a foaming agent.

Incidentally, when the purpose is to color the molded product or to obtain a colorless molded product, decolorization treatment of the leather powder itself to be mixed and coloration and mixing of a color pigment during resin molding are performed. . The coloring of the leather material is mainly based on the dyeing method, and the heating step using the steam heating device in the above step and the dyeing in the state of the crushed leather before this heating step are the most effective.

It should be noted that the resin molded in the above may be mixed with an appropriate amount of plasticizer, modifier, extender, etc.
Molding of hard, semi-hard and soft resin molded products.

Further, as the resin molding means, calender rolls, extrusion, injection and other methods may be used to provide mainly sheet or film-shaped molded products, but the present invention is not limited to sheets and films, and handle and other It is also suitable for providing molded products.

Then, the surface of these sheets, films or various molded products may be subjected to a treatment such as sandblasting, sanding or surface slicing, and the skin layer portion of the resin may be removed.As a result, it is considered as a deeply suede-like product, Moreover, the feel of the product was similar to that of genuine leather. Further, in the case of a sheet or film molded product, a tearing strength may be increased by attaching a backing material of paper or cloth to this, and in particular, sanding may be facilitated.

Sheets, films and various molded products molded in this way are subjected to embossing treatment with a Shibo roll or the like,
Alternatively, by kneading it to give a leather grain, or as a brushed backskin, suede-like leather, and by applying the same processing as ordinary leather such as enamel leather using various paints, matte leather, etc. It was possible to provide a leather-like molded product that suits the purpose.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the device according to the present invention, and FIG. 2 is a graph showing changes in temperature of the leather strip B with time. In the figure, 1 ... inner wall, 2 ... outer wall, 3 ... gap, 4 ...
Processing chamber, 5 ... stirring blade, 6 ... rotating shaft, 7 ... drain.

Claims (1)

[Claims] 1. A leather material put into a processing chamber is taken out after being subjected to a stirring process under a heating condition from a supply steam and a wall surface of the processing chamber, and dried so that a moisture content is within 4%. A method for crushing leather, which is characterized by being crushed.