JPH01163215A - Method for mixing leather powder with resin - Google Patents

Abstract

PURPOSE:To provide a leather powder-containing resin material containing homogeneously dispersed fine leather powder therein and useful for coatings, etc., by grinding dry leather powder having a low water content together with a solvent by a wet type grinding machine and subsequently mixing the reground leather powder-containing solvent with a resin material. CONSTITUTION:Leather powder having a water content of <=5wt.% is first ground together with a solvent by a wet type grinding machine such as a ball mill. The ground leather powder-containing solvent is subsequently mixed with a resin material such as a polyurethane resin. The above-mentioned leather powder is preferably one obtained by applying a steam heating process to a raw leather material to decompose the triply helical structure of the leather tissue, drying the decomposed leather material to a water content of <=3wt.% and subsequently grinding the dried leather material by a grinding machine. A solvent capable of dissolving the resin to be mixed with the leather powder is satisfactory for the above-mentioned solvent.

Description

Detailed Description of the Invention (Field of Industrial Application) This invention is a method for producing leather that is ideal for producing resin materials such as solutions or pastes containing fine leather powder used for paints, coatings, film forming, etc. Regarding the method of mixing powder and resin, in more detail, resin solutions or resin pastes for various uses contain fine natural leather powder, and this fine leather powder is not contained in these resins. This invention relates to a method of mixing leather powder and resin that is optimal for producing resin materials in the form of solutions or pastes that are evenly distributed.

(Conventional technology) Natural leather (skin refers to the leather that has not been rubbed, and leather refers to the leather that has been rubbed; the same applies hereinafter) is crushed into a fine powder, and this crushed leather powder is made into various types. Various attempts have been made to form leather-like coatings and produce sheets, films, etc. by mixing them into synthetic resin materials.

However, natural leather weighs 40g in dry condition.
Although it is theoretically possible to continuously grind into finer leather powder, there are various disadvantages in actual mass production at a commercial pace.

Therefore, in the case of a plant that continuously grinds leather, the particle size is approximately 40 to 801 Lm (measured particle size in the present invention is measured on the short axis side when the leather powder is elongated. Leather powder that falls within the range of had.

Furthermore, when the leather powder thus pulverized is mixed with diagonal coating or various synthetic resin liquids or resin materials in a plastic state, the mixed leather powder does not mix with these resin materials and is mixed with cotton. It was found that these particles aggregated in a shape and were difficult to be evenly dispersed in these coating liquids, synthetic resin liquids, or resin materials.

(Problems to be Solved by the Invention) From this point of view, leather powder prepared by pulverizing to a particle size of 40 to 80 gm is dried, and a polyurethane resin liquid (-liquid The leather powder is re-pulverized using a batch-type wet medium (pole) stirring pulverizer by adding 20% by weight to the leather powder (including both type and two-component type, the same applies hereinafter), and kneading with the polyurethane resin liquid. I tried.

However, in this method, since the resin liquid is impregnated into the leather powder, the fluidity of the resin liquid tends to be gradually inhibited and the viscosity of the resin liquid gradually increases as the mixture is stirred and pulverized. As a result, it was found that it was difficult to evenly disperse the input leather powder in the resin liquid, and the input leather powder was unevenly distributed in the resin material in an agglomerated state. This was the same even when the grinding time was set to a long time, and it was impossible to re-grind the leather powder into a fine powder and ensure uniform dispersion in the resin liquid. It has been observed that the same phenomenon occurs in a so-called polyurethane resin solution containing a solvent such as 20 parts of leather powder mixed with 100 parts of a polyurethane resin solution containing a solid content of 30% by weight. When the solution was poured into a machine and stirred and pulverized, the solution was rapidly impregnated into the input leather powder, and as the solution was stirred, the fluidity of the solution was gradually inhibited, and the viscosity of the polyurethane resin in the resin solution gradually increased. It was accepted that this would happen. For this reason, even when leather powder is added to a polyurethane resin solution containing a solvent such as toluene and stirred, the leather powder is not uniformly dispersed in the solution.
It became clear that pulverization by re-grinding was not sufficient.

In addition, in such stirring and grinding methods, the flow resistance of the resin liquid or resin solution is high, and the leather powder may come into direct contact with the grinding medium poles without the intervention of the resin liquid or resin solution. Since the treatment temperature is rapidly raised with these stirrings, there is a problem in that a reaction hardening situation of the polyurethane resin is created.

Such inconveniences occur not only when using polyurethane resins but also when vinyl chloride resins, acrylic resins, etc. are used. When % of the above leather powder was added and stirred and mixed, it was found that most of the added leather powder aggregated in the form of cotton and was not dispersed in the paste-like resin material.

Furthermore, when 20% by weight of the leather powder was added to a resin solution prepared by sufficiently diluting these vinyl chloride resins, acrylic resins, etc. with a solvent and mixed with stirring, the viscosity of the resin solution decreased as the stirring time progressed. The leather powder was too high to be sufficiently dispersed in the resin solution. Furthermore, there is a problem in that the temperature inside the stirrer rapidly increases as a result of this stirring. Furthermore, when the particle size of the leather powder after stirring and pulverization was examined, it was found that the particle size of the leather powder was not much different from the particle size of the leather powder when it was added, and the pulverization efficiency was extremely poor.

Furthermore, when the leather powder stirred and crushed by the above method is taken out together with the leather powder-containing resin or resin solution and a solvent such as toluene is added thereto to form a diluted solution,
There was an inconvenience that the dilution with toluene etc. could not be carried out smoothly.

The present invention eliminates the disadvantages of the conventional manufacturing method, pulverizes the grass powder to finer than 40jLm, and disperses this pulverized leather powder evenly in a solution or paste resin such as a polyurethane resin solution. The present invention provides a mixing method for mixing.

(Means for Solving the Problems) For the above-mentioned purpose, the present invention uses powder that has been pulverized in advance and makes it dry so that the water content is within 5% by weight. This dry powder is then pulverized using a wet pulverizer together with a solvent such as toluene.

Then, by mixing a solvent containing this re-pulverized powder with the resin material to be used, a solution or paste containing the above-mentioned pulverized powder uniformly for forming a coating film or forming a sheet, film, etc. The goal was to create a resin material for this purpose.

(Function) In the present invention, this powder is stirred and ground in a wet grinder together with a solvent suitable for the resin to be used, such as toluene, methyl ethyl ketone, and dimethyl formamide.
Even if a solvent is impregnated into the treated powder during pulverization, the viscosity of the solvent itself will not increase, and the flow resistance associated with stirring and pulverization in a wet pulverizer will not increase.

In addition, since the solvent used to crush and stir this powder does not contain the target resin and the solvent itself has low viscosity, the powder mixed in the solvent remains uniformly dispersed in the solvent. The agitation and pulverization processes are performed using a wet pulverizer.

Next, the powder that has been pulverized with a solvent in a wet pulverizer is uniformly dispersed in the solvent, so when mixed with the resin material to be used, the powder mixed in the resin solution or resin paste will be removed from the solution. Alternatively, it will be uniformly dispersed within the paste.

(Example) An example of the method of mixing the powder and resin according to the present invention will be described below.

First of all, the leather used in the present invention is treated with tannin or chromium to prevent hardening and mold generation due to heat treatment, and mainly cowhide, pigskin, and sheepskin treated with chromium are used. Shaving waste such as This shaving waste is then treated with toluene, methyl chloride, etc. to remove as much of the lipids contained in the shaving waste as possible. This removal of lipids is effective in preventing discoloration of the molded main powder. are doing. Therefore, this powder is suitable for molding molded products or forming paint films that may cause a certain degree of yellowing, or it is suitable for molding molded products or forming paint films where yellowing can be hidden by coloring. The manufacturing process does not require this lipid removal step.

Next, in order to enable the re-pulverization described below, the above-mentioned shaving waste is first pulverized using a pulverizer such as Fine Victory Mill until the moisture content is within 5% by weight, ideally 2. Pulverized main flour having a moisture content of around 3% by weight is prepared.

More ideally, this pulverized main powder can be produced by applying steam heating to the raw material itself, as shown in the invention of Japanese Patent Application No. 82-59832 filed by the present applicant. After the triple helical structure of the leather tissue is disrupted by repeated swelling and tissue contraction, the treated leather is dried and the above-mentioned fine is dried so that the moisture content is within 3% by weight. By grinding with a Victory Mill, a ground powder with an apparent specific gravity of 0.38 to 0.50 g/cc is prepared.

In addition, the appearance of the crushed main powder mentioned above does not necessarily mean that the specific gravity is 0.
The present invention does not require that the specific gravity be within the range of 38 to 0.50 g/cc, and the apparent specific gravity is 0. This powder can also be used, but the larger the apparent specific gravity, the less likely it is to aggregate into flocculent particles when pulverized using a wet pulverizer. (In this invention, the apparent specific gravity is the loose apparent specific gravity, which is calculated by slicing and weighing the powder in a 100 cc container, dividing the weight of the powder by 100.
It is shown in ) This ground powder is then re-pulverized with a water content of 5% by weight or less, ideally around 2.3% by weight. In addition, it is necessary to re-pulverize the resin material using a wet pulverizer, to dissolve or fluidize the resin material, and to reduce the amount to a level that does not cause any inconvenience when using the solutionized or fluidized resin material. By lowering the water content in the ground powder, it is possible to reduce the amount of water used in the re-grinding process in a solvent using a wet grinder, in the solution and fluidization of the target resin, and in the use of the solution or fluidized resin material. This eliminates the inconvenience of moisture being contained in the target resin or the formation of water vapor bubbles. Furthermore, by controlling the water content of the powder to within the above-mentioned 5% by weight during re-pulverization, the elasticity of the powder can be suppressed as much as possible and the effect of pulverization can be enhanced.

In the present invention, by keeping the particle size of the powder crushed above within a certain range, the pulverization treatment and mixing with the solvent during re-grinding using a wet crusher described below can be carried out more reliably. To efficiently re-grind the powder with the desired fine particle size and efficiently disperse it in a solvent.
did. From this point of view, the particle size of the powder suitable for this re-grinding is finer than 8Q4m.
Ideally, it is 5% (volume ratio) or more.

In this example, powder having the following particle size distribution was used and pulverized using a wet pulverizer. (% indicates volume ratio.

) 4.001Lm or more - less than 5.04JLm 0.0%
5.04/l ~ B, 35 tr
O, 5%E1.35 // ~ 8.00
tt 1.0%8.00 // ~10
．． 1 // 1.8%10.1 tt
~12.7 /I 2.9%12.7
// ~18. Ott 4.7%113.
0/l ~20-2 // 5.9
%20.2/l ~25.4 //
7.0%25.4 // ~32.0/l
B, 4%32.0/l ~40-3
// 11.8%40.3 //
~5G, 8 // 14.8% 50.8. t
t ~134.0/l 17.2%B
4. Q // ~B0.8 /l 1
4.4%B0.8 // ~102. tt
8.7%102, tt~128.
/l 2.5%128,
tt~181. /l
O, 8% Next, the above-mentioned powder was put into the grinding tank l of a wet stirring grinder together with a solvent such as toluene, methyl ethyl ketone, dimethyl formamide, etc. which is commonly used for the resin to be used, and the powder was mixed into the following particles. The mixture was stirred and crushed until it had a diameter. (% is indicated by volume ratio.) 1.284m or more - less than 1.591Lm 0.0%1
．． 59 // ~2.00 // 1
．． 2%2.00/I ~2.52 //
2.3%2.52 // ~3.17
// 4.8%3.17 1/ ~4.0
0 // 8.8%4.00 //
~5.04/l 14.3%5.04
// ~B, 35 /I 18.0%Ei
, 35 tt ~8-00 // 1
4.5%8.00/1 ~10.1/l
12.8%10.1 // ~12.7
// 11.0%12.7 /I
~18.0 // 7.7%1B,Q
// ~20.2 // 4.5%2
0.2 // ~25.4 //
L, 8%25.4tt~3
2.0/IO,6%32,Ot
t ~40.3 // 0.
3%40.3tt ~50.8
/I O, 0% The wet stirring pulverizer used may be a ball mill, a tube mill, a compound mill, a conical mill, a colloid mill, etc., or a wet stirring pulverizer having other suitable configurations.

In addition, in the wet stirring crusher used in the above embodiment, a crushing tank l is filled with a pole 2, and this pole 2 is connected to a stirring rod 3a.
It has a configuration in which stirring is performed using a stirring shaft 3 having a
The circumferential wall of the crushing tank 1 is made up of two layers of circumferential walls 1a and lb, and a gap 4 is provided between the circumferential walls 1a and lb so that cooling water can be sent therebetween.

The above-mentioned re-ground main powder was placed in a tank l with a pole 2 with a diameter of 3 mm.
The rotation of the stirring shaft 3 was set to 10 Or, pJ,
Seal the powder and add 100 fL of toluene containing this powder to it.
It was obtained by adding FJ1812 for 1.5 hours and stirring. The amount of leather powder mixed in this toluene is 5% by weight ~
If the content is 50% by weight, but it is within 50% by weight, sufficient stirring and pulverization is possible, and in the above example, 30% by weight was mixed.

The above-mentioned solvents may be soluble solvents for the resin to be used, and in addition to the above-mentioned toluene, methanol, inpropyl alcohol, benzine alcohol, ethyl acetate, and butyl acetate may be used to suit the resin to be used. , acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexane, tetrahydrofuran, dioxane, quidylole, dimethylformamide, 2-nitropropane,
Dichloramide, trichlorethylene, perchlorethylene, and various other solvents were used as practical solvents.

In this way, a solvent containing the above-mentioned fine main powder re-pulverized by a wet stirring pulverizer is produced, and resin materials to be used in this solvent, particularly polyurethane resin, vinyl chloride resin, acrylic resin, etc. Mix synthetic resin materials to create the desired resin material in the form of a solution or paste.

In the above-mentioned example, the main powder belonging to a range finer than 18ILm accounted for 32.8% (volume ratio) of the total amount, and in many other examples, the main powder belonging to a range finer than lfltgm was obtained by the above method. is at least 85% of the total amount of leather powder
(volume ratio) or more.

The resin material to be used is mixed with the solvent containing the fine powder in a uniformly dispersed state.

The resin material to be used may be in liquid form, paste form, or powder form.

By adjusting the blending amount of the resin material mixed in the solvent containing the powder, it was possible to obtain a resin material in the form of a paste, a highly viscous solution, or a diluted solution with a weak viscosity.

Making the resin material produced in this way have various flow characteristics corresponds to the purpose of use of the resin material produced. For example, by preparing a paste-like resin material and molding it with a calendar roll. Provided for the production of grass-like sheets or films by. In addition, by preparing a relatively viscous resin material in the form of a resin solution and applying it directly to the surface of woven, knitted or non-woven fabric, paper, etc. using a method such as doctor knife coating, it is possible to create a grass-like surface. For the production of fabrics, etc., or for woven, knitted,
By soaking non-woven fabric, paper, etc. in the resin material in the form of a solution, it was possible to manufacture fabrics etc. that had a grass-like appearance as a whole.

Furthermore, the above-mentioned resin material in the form of a resin solution is applied to a release paper surface with a smooth glossy surface using a doctor knife coating method to a thickness of 0.2 to 0.8 mm, and dried to form an ultra-thin material that can be peeled off. It could be used to produce a grass-like film. In addition, 0, 2 to 0 once coated and formed on this release paper surface.
．． By transferring and adhering a grass-like film having a thickness of 8 mm to the surface of woven, knitted or non-woven fabric, paper, synthetic leather, etc., it was possible to manufacture fabrics having an ultra-thin grass-like film on the surface.

Furthermore, the resin material in the form of a resin solution was further diluted and the viscosity was made as low as possible before it could be used as a paint.

The solution resin material prepared as this paint will not clog the nozzle when sprayed with a spray gun, and the powder mixed in will not aggregate into flocs when applied with a brush or roll. It is possible to form a coating film with smooth surface characteristics without any grains, making it ideal for forming grass-like coating films.

Since this paint film evenly contains extremely fine powder, it can be applied to the surfaces of various types of furniture, resin molded products, films or sheets, as well as cloth, artificial leather, and natural leather. As a result, we were able to improve the unique texture, water resistance, and abrasion resistance of these materials.

Further, on the surface of a vinyl chloride or acrylic film, sheet, etc. that has already been made from a solution-like or paste-like resin material containing the above-mentioned present powder, coating made of the above-mentioned polyurethane-based solution-like resin material may be applied. A film with good wear resistance and chemical resistance by forming a coating film,
It could be used as a sheet etc.

An example in which a polyurethane resin solution is used as the resin material will be described below.

The polyurethane resin used in the production of the solution resin material containing leather powder used toluene diisocyanate, diphenylmethane-4,4°-diisocyanate, hexamethylene diisocyanate, etc. as isocyanate. In addition, adipic acid glycol, polypropylene glycol, etc. were used as the polyol. Moreover, both one-component type and two-component type of this polyurethane resin were used.

In addition, the polyurethane resin and the solvent containing the crushed leather powder can be mixed with the above-mentioned wet stirring crusher, or by stirring with a general stirring machine such as a ball mill, tube mill, compound mill, conical mill, colloid mill, etc. It was also found that the solution could be reliably made into a solution, and that the leather powder mixed in the solution was uniformly dispersed.

In addition, a polyurethane resin solution for painting is prepared by mixing the above-mentioned polyurethane resin, solvent, and leather powder at a ratio of 10 parts of leather powder to 100 parts of toluene containing 30% by weight of polyurethane resin solid content. I was able to do that. Also, a polyurethane resin solution prepared in the same manner was applied to a release paper in the form of a coating, and then peeled off.
It was possible to produce a polyurethane resin film having a thickness of 2 to 0.8 s+. Furthermore, by coating a polyurethane resin solution prepared in the same manner on non-woven fabrics, woven or knitted fabrics, etc., it was possible to create ultra-thin polyurethane resin films on the surfaces of these fabrics. Furthermore, by soaking the nonwoven fabrics, etc. in a polyurethane resin solution prepared in the same manner, it was possible to impregnate the inside of these nonwoven fabrics, etc. with the polyurethane resin liquid containing leather powder.

Next, the polyvinyl chloride resin was mixed with a solvent such as benzine, toluene, ester, or ketone impregnated with leather powder using the method described above. As an example of manufacturing the resin material based on this polyvinyl chloride resin, 70 parts by weight of toluene, 1 part of leather powder,
Leather-like polyvinyl chloride sheets, films, coatings, etc. could be produced using 0 parts by weight of polyvinyl chloride resin and 30 parts by weight of polyvinyl chloride resin.

Similarly, a leather-like film, sheet coating, etc. can be produced using 15 parts by weight of polyvinyl chloride resin, 15 parts by weight of acrylic resin, 70 parts by weight of toluene, and 10 parts by weight of leather powder.

Furthermore, 70 parts by weight of a solvent such as methanol, benzine alcohol, toluene, benzine, etc., impregnated with leather powder using the method described above, 10 parts by weight of leather powder, and 30 parts by weight of acrylic resin were added to the acrylic resin.
Leather-like acrylic resin film by weight part,
We were able to create sheets, coatings, etc.

The paint film, film, coating film, or non-woven fabric made by the above method uniformly contains leather powder whose amount is 85% or more of the total amount of leather powder, which is finer than the 187zm mentioned above, so the surface feels rough. It has the smooth and moist properties unique to leather, has no sticky texture, has moderate moisture absorption, and does not feel sticky when it comes in contact with it.

Therefore, it is used for surface coating of automobile steering wheels, automobile interior materials, various handles, furniture, etc., as well as cloth,
It is used for sheets and films that are pasted onto the surfaces of paper, metal plates, resin plates, etc., and it is also used to make non-woven fabrics into a leather-like material. Ru.

In addition, since the coating surface that is formed has properties unique to leather, it can be subjected to cosmetic treatments similar to those normally applied to leather, and can also be used to create a leather grain pattern by applying grain, or to create a pattern. Unique patterns such as crocodile leather can be created by pressing. Furthermore, by applying a sanding treatment to the surface of the coating film, film, or sheet produced using the above-mentioned resin material, the properties of the mixed leather powder can be brought out even more effectively.

(Effect) In the present invention, as a pre-process to mix leather powder into the resin to be used, after the leather is ground and prepared in the first step, the leather powder is mixed in a low viscosity liquid using a solvent such as toluene. Because of the re-grinding process, the leather powder is re-grinded while being dispersed in this solvent, and the re-grinding is done in a relatively short time and reliably.
It also has the advantage of being smooth and re-pulverizing the crushed leather powder without intertwining with each other.

In addition, since there are no substances that interfere with stirring, such as the solid content of the resin that is used in the re-grinding process, there is less heat generated during stirring and crushing, and the leather powder that has been stirred and re-grinded is free of toluene, etc. Because it is uniformly dispersed in the solvent, it has the advantage of being easily and uniformly mixed with the resin liquid to be used.

From the above points, the resin material such as the polyurethane resin solution according to the present invention has fine re-ground leather powder containing 85% or more of the total amount of leather powder in a finer range than 113ILm in a uniformly dispersed state. The paint film, film, or sheet formed using a resin material such as this resin solution evenly contains mixed leather powder, and the mixed leather powder may be ubiquitous in some parts of the paint film, film, or sheet. .

It was possible to provide a coating, film, or sheet that does not agglomerate, has a uniform thickness, and has uniform leather powder evenly throughout.

In addition, the leather powder contained in the resin material such as the resin solution is re-pulverized to produce a leather powder containing 85% or more of the total amount of leather powder finer than 16 pm. It was possible to create a smooth surface without any roughness on the sheet surface.

In addition, when the molded film, paint film, etc. is based on a polyurethane resin material, the molded sheet, film, paint film, etc. has the feature of being physically and chemically strong.

Furthermore, when the film, sheet, coating film, etc. to be formed is based on polyvinyl chloride resin or acrylic resin, it has the feature that it does not undergo hydrolysis.

[Brief explanation of the drawing]

The accompanying drawing is a perspective view of a main part of a wet stirring pulverizer according to the present invention cut away. l...tank, 2...pole, 3...stirring shaft, 4
···gap.

Claims (1)

[Claims] A mixture of leather powder and resin, which is obtained by pulverizing leather powder with a moisture content of 5% by weight or less together with a solvent in a wet pulverizer, and mixing the solvent containing the pulverized leather powder with a resin material. Method.