JPH0291279A - Production of synthetic leather and production thereof - Google Patents

Abstract

PURPOSE:To obtain a flexible synthetic leather rich in moisture permeability by laminating a urethane resin layer containing fine gelatin powder to the surface of a wet microcellular layer of a polyurethane resin laminated to the surface of a substrate, dissolving and removing the above-mentioned gelatin powder. CONSTITUTION:For example, a polyurethane resin solution containing fine gelatin powder 8 is applied to the surface of a creped mold release paper 7 and dried to form a layer 11 of the above-mentioned resin. A substrate having a wet microcellular layer 4 of a polyurethane resin is then thermocompressed and laminated to one surface of a substrate 2, such as nylon or polyester and the mold release paper 7 is subsequently peeled to provide a laminated body 15 having the polyurethane resin 11 for forming the skin layer laminated thereto is obtained. The laminated body 15 is then dipped in hot water to dissolve and remove the afore-mentioned gelatin 8 and afford a synthetic leather 1 having the cellular skin layer formed thereon. The resultant synthetic leather is flexible, excellent in moisture and air permeability and improved in drapeability.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to synthetic leather and a method for producing the same.

[Conventional technology]

In recent years, instead of natural leather, artificial leather and synthetic leather, which are formed by laminating a synthetic resin elastic body such as polyurethane on a base material such as woven fabric or non-woven fabric, have become widely used. Various improvements have been made to make the appearance, feel, feel, moisture permeability, etc. of synthetic leather more similar to natural leather.

As a method to bring the texture, touch, moisture permeability, etc. of artificial leather and synthetic leather closer to those of natural leather, a method has been proposed in which natural leather powder is added to synthetic resin.
0 mesh (approximately 300 to 60μ) of natural leather powder was added to a thermoplastic resin compound with a weight ratio of 70 to 30% based on the leather powder, and a blowing agent was further added to this and mixed. After that, a water-miscible organic solvent solution of polyurethane elastomer is applied to the artificial leather (Japanese Unexamined Patent Publication No. 10641/1988) made into a foamed sheet by hot rolling, and the solution is immersed in water to solidify and form a base material. Artificial leather and the like are known in which a wet microporous layer is formed on the material.

[Problem to be solved by the invention]

However, since the artificial leather described in JP-A No. 63-10641 is heat-rolled and foamed to form a sheet, a so-called skin layer is formed on the epidermis, and this skin layer allows natural leather powder to be The addition of this material impairs the natural leather-like feel, and also results in poor moisture permeability and air permeability. For this reason, it is necessary to slice and remove the skin layer, which complicates the manufacturing process, and because natural leather powder is added to the resin and foamed, the natural leather powder is dispersed throughout the artificial leather. Therefore, unless a large amount of natural leather powder is added, the surface feel cannot be sufficiently improved, and if a large amount of natural leather powder is added, although the surface feel can be improved, the strength of the entire leather decreases. However, it had contradictory drawbacks, such as making it impractical for practical use.

On the other hand, artificial leather and synthetic leather are made by coating a base material with a water-miscible organic solvent solution of polyurethane elastomer, immersing it in water to solidify it, and forming a wet microporous layer on the base material. Not only does it closely resemble natural leather in appearance and feel, but it also has excellent moisture permeability, but its appearance is far from natural leather, and it is inferior in strength such as abrasion resistance, so it cannot be used as is as artificial or synthetic leather. It was impossible. Therefore, a surface treatment agent made of a solution of a polyurethane resin in a solvent is applied onto the wet microporous layer and dried by heating to form a surface treatment layer. However, this surface treatment layer has no moisture permeability, and must be formed in dots using a gravure printing method or the like to inhibit the moisture permeability of the wet microporous layer.
This method has the disadvantage that it is not possible to obtain artificial leather or synthetic leather with improved moisture permeability and abrasion resistance.

[Means to solve the problem]

The present invention solves the above-mentioned drawbacks of the prior art, improves appearance, texture,
It is an object of the present invention to provide synthetic leather that is excellent in feel, etc. and also in physical properties such as moisture permeability and air permeability, and a method for producing the same.

That is, the present invention provides the following features: (1) A wet microporous layer of polyurethane resin is laminated and integrated on at least one side of a base material, and a polyurethane resin layer containing fine gelatin powder is further laminated and integrated on the surface thereof, and then a polyurethane resin layer is formed. Synthetic leather characterized by having a porous skin layer made by dissolving and removing fine gelatin powder inside.

(2) A wet microporous layer of polyurethane resin is formed by applying a water-miscible organic solvent solution of polyurethane resin to one side of the base material, and then immersing it in water to remove the solvent and coagulating the polyurethane. After forming a polyurethane resin layer containing fine gelatin powder on the surface thereof, the laminate is immersed in hot water to dissolve and remove the fine gelatin powder to form a porous skin layer. Characteristic synthetic leather manufacturing method.

(3) In the method for producing synthetic leather according to claim 2, the laminate having a polyurethane resin layer containing fine gelatin powder is immersed in hot water and subjected to a rubbing treatment to dissolve and remove the fine gelatin powder; A method for producing synthetic leather, characterized by forming a porous skin layer.

(4) In the method for producing synthetic leather according to claim 2, the laminate having a polyurethane resin layer containing fine gelatin powder is immersed in hot water and squeezed with nip rolls to dissolve the fine gelatin powder. A method for producing synthetic leather, which comprises removing the skin and forming a porous skin layer.

(5) The method for producing synthetic leather according to claim 3, characterized in that the rubbing treatment is performed using a jet dyeing machine.

The main points are as follows.

〔Example] Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 1 shows an embodiment of the synthetic leather 1 of the present invention, where 2 is a base material and 3 is a skin layer that is integrated with the base material 2 through a wet microporous layer 4 of polyurethane resin. A large number of micropores 5 are formed in the layer 3.

The base material 2 may be a woven fabric made of fibers such as nylon, polyester, cotton, or rayon alone or a blend of these fibers;
Nonwoven fabrics, knitted fabrics, etc. are used. The skin layer 3 is made of polyurethane resin, and examples of the polyurethane resin include polyester polyurethane, polyether polyurethane,
Any of polycaprolactone-based polyurethane, polycarbonate-based polyurethane, etc. can be used.

An adhesive may be used to bond the skin layer 3 and the wet microporous N4, but if an adhesive is used, a large number of micropores must also be formed in the adhesive layer to be formed. . When the skin layer 3 is laminated and integrated with the wet microporous layer 4 by a heating lamination method or the like, it is not necessarily necessary to use an adhesive.

As the adhesive, two-component polyurethane resins such as polyester polyurethane, polyether polyurethane, polycaprolactone polyurethane, and polycarbonate polyurethane can be used.

Incidentally, a coloring agent such as a pigment or dye can be added in the skin layer 3 for the purpose of coloring the skin layer 3 or, if necessary, in an adhesive layer provided for the purpose of adhering the skin layer 3. Also, epidermal layer 3
If necessary, other additives such as various stabilizers and fillers may also be added thereto.

The wet microporous layer 4 is formed by applying a polyurethane resin dissolved in a water-miscible organic solvent (such as DMF) to the surface of the base material 2 and then immersing it in water to remove the solvent and solidify the polyurethane resin. It can be formed as a layer with holes 6.

As shown in FIGS. 2 and 3, the synthetic leather l of the present invention is produced by uniformly applying a solution of a polyurethane resin for forming a skin layer containing fine gelatin powder 8 to the grained surface of a grained release paper 7 using a doctor knife 9 or the like. After coating to a thickness, heat in oven 10
Sheet 12 was dried inside to form a polyurethane resin layer 11 for forming a skin layer containing fine gelatin powder, and then a wet microporous layer 4 was formed on the base material 2 by the method described above.
The wet microporous layer 4 is superimposed on the wet microporous layer 4, heated by a heating roll 13 to bond them together under thermocompression, and further passed through a heating oven 14 to completely volatilize the remaining solvent, and then the release paper 7 is peeled off. A laminate 15 was obtained in which the polyurethane resin layer 11 for forming the skin layer was transferred and laminated on the wet microporous N4 surface of the base material 2 (in addition, gelatin was applied to both sides of the wet microporous layer laminated and integrated on both sides of the base material). When the polyurethane resin layer 11 for forming a skin layer containing the fine powder 8 is laminated and integrated, the above steps may be carried out on both the front and back sides of the base material.) After sintering, this laminate 15 is heated. The gelatin fine powder 8 is dissolved and removed by immersion in water to form an epidermis N having micropores 5.
It can be manufactured by the method of forming No. 3. The gelatin fine powder 8 has a particle size of 30 μm or less, particularly 20 μm.
The following are preferred. When gelatin with a particle size of 30 μm or more is added, streaks are likely to occur on the surface of the skin layer 3, although it depends on the thickness of the skin layer 3. The amount of gelatin fine powder 8 added is 100 to 20% by weight, especially 70 to 3% by weight based on the amount of urethane resin.
0% by weight is preferable; if the amount of fine gelatin powder 8 added is too large, moisture permeability and air permeability will be good, but the membrane strength will drop significantly, and if it is too small, no improvement in moisture permeability and air permeability can be expected. The gelatin fine powder 8 is dissolved and removed at 80-120°C.
It is preferable to immerse one laminate 15 in hot water for about 0.5 to 2 hours. Furthermore, if the fine gelatin powder 8 is dissolved and removed while being rubbed or squeezed with nip rolls, the rate of dissolution and removal of the fine gelatin powder can be improved and the softening process can be performed at the same time.

This rolling treatment can be carried out well by using a jet dyeing machine. When performing rolling treatment with a jet dyeing machine, the cloth speed (speed of the material to be treated) is 100 to 500 m/min, and the working pressure is 1
It is preferable to carry out under the condition of ~4 kg/c+ll. If it is carried out outside this range, there is a risk that the efficiency of dissolving and removing the fine gelatin powder 8 will hardly be improved or that the synthetic leather itself will be damaged.

Further, when using nip rolls, it is more effective to provide a plurality of nip rolls. It is preferable that the gap between the two rolls of the nip roll be set smaller than the thickness of the laminate 15 so that when the laminate 15 passes between the two rolls of the nip roll, it is pressed and squeezed by the two rolls.

When the gap between the two nip rolls is O, the laminate 1
When the liquid is squeezed through 5, large wrinkles appear in the laminate, which is undesirable.

Note that the rubbing treatment may be performed in a separate step after dissolving and removing the gelatin fine powder.

The above example shows the case where the skin layer forming polyurethane resin layer 11 containing fine gelatin powder 8 is laminated and integrated with the wet microporous layer 4 by heating lamination. In this case, fine gelatin powder 8 is also included in the adhesive. This is to ensure that the fine gelatin powder 8 contained in the polyurethane resin layer for forming the skin layer is efficiently dissolved and removed from both the front and back sides of the laminate 15. Also, when a surface treatment layer is further provided on the surface of the skin layer 3 if necessary, the gelatin fine powder contained in the polyurethane resin layer for forming the skin layer can be easily dissolved and removed.
Fine gelatin powder is also included in the polyurethane solution for forming the surface treatment layer. This surface treatment layer is made by coating a polyurethane resin for forming a skin layer containing fine gelatin powder and drying it to form a resin layer, and then applying a polyurethane resin solution containing fine gelatin powder by a gravure coating method or the like during drying. It can be formed by coating and drying in an amount of about 1 to 5 g/rIf, and then dissolving and removing the fine gelatin powder in hot water. As the polyurethane resin solution used to form this surface treatment layer, in addition to ordinary polyurethane resins, silicon-modified polyurethane resins, amino acid-modified polyurethane resins, polyamide-modified polyurethane resins, etc. are used.

Hereinafter, the present invention will be explained in more detail by giving specific examples.

Example 1 A 12% DMF solution of a polyester polyurethane resin (manufactured by Dainippon Ink: Crisbon MP812NB) with a 100% modulus of 20 kg/crl was applied to the rough brushed surface of a fine denier polyester woven fabric with a thickness of 0.4 mm. 7
00 g/rrr, then desolvated in water at 20°C to solidify, then dehydrated and dried under hot air at 120"C to form a wet microporous layer with a thickness of 0.6 mm. A substrate was obtained.

On the other hand, on the surface of the textured release paper, 20% DMF of a polyester polyurethane resin (Nishizamine ME3612LP manufactured by Dainichiseika Chemical Co., Ltd.) containing 50% by weight of fine gelatin powder with an average particle size of 10 μm and a 100% modulus of 60 kg/at was applied.
- MEK solution (contains 15 parts by weight of colorant per 100 parts by weight of polyurethane resin) with a dry thickness of 30
Apply with ε knife coater to make μ and 90'C.
After drying for 2 minutes to form a polyurethane resin layer, the wet microporous layer surface of the substrate having the wet microporous layer was bonded to the top surface of the polyurethane resin layer by thermocompression at 130°C while heating. After peeling off the release paper, a polyurethane resin layer containing fine gelatin powder was transferred and laminated on the surface of the substrate. This laminate is dyed using a jet dyeing machine at a rate of 250 m/min.
5 at 100°C under pressure 1.5 kg/ci
The fine gelatin powder was dissolved and removed while being rubbed for 0 minutes to obtain synthetic leather.

The resulting synthetic leather has a soft texture and drapability.
Moreover, it retained its wrinkles after being rubbed for a long period of time, was extremely flexible, and had an appearance and feel very similar to natural leather, making it suitable as a material for clothing. The moisture permeability of this synthetic leather (
According to JIS Z-0208) is 3860g/rrr・
24 hours, and the air permeability (according to JIS L-1096) was 0.6 cc/cffl-sec, indicating excellent moisture permeability.

Comparative Example 1 Synthetic leather was obtained in the same manner as in Example 1 except that gelatin fine powder was not added (rubbing treatment using a jet dyeing machine was also performed in the same manner). The moisture permeability of the obtained synthetic leather is 1530g/r
rr・24 hours, air permeability is 0.2 cc/c
It was less than i seconds, and the moisture permeability was also poor.

〔Effect of the invention〕

As explained above, the synthetic leather of the present invention is produced by providing a polyurethane resin layer containing fine gelatin powder on the surface of the wet microporous layer of a substrate provided with the wet microporous layer, and then forming a polyurethane resin layer containing fine gelatin powder in the polyurethane resin layer. Because it has a porous skin layer made by dissolving and removing powder, it has excellent moisture permeability and air permeability, and is extremely flexible with a soft feel and drapability, and has an extremely natural appearance and texture. It is a synthetic leather similar to leather. Furthermore, since a wet microporous layer formed by a wet method is provided between the skin layer and the base material, it has excellent flexibility.

Furthermore, according to the method of the present invention, it is possible to efficiently produce synthetic leather provided with a skin layer having the above-mentioned micropores, and furthermore, the gelatin fine powder can be dissolved and removed by squeezing with nip rolls, and the gelatin If a kneading treatment is performed at the same time as the gelatin powder is dissolved and removed, the fine gelatin powder can be removed more effectively, and a softening treatment can also be performed at the same time. Furthermore, if a jet dyeing machine is used for this rolling process, the removal of fine gelatin powder and the softening process can be carried out very efficiently.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, FIG. 1 is a longitudinal cross-sectional view showing one embodiment of the synthetic leather of the present invention, FIG. 2 is an explanatory diagram showing the manufacturing process of the synthetic leather of the present invention, and FIG. FIG. 3 is a vertical cross-sectional view taken along the line ■-■ in FIG. 2; 1... Synthetic leather, leather 2... Base material type microporous layer 5... Micropores 8... Fine gelatin powder 1 Urethane resin layer 3... Skin layer 4... Moisture 6... Desorption Hole 1 due to solvent...polymer for forming skin layer

Claims (5)

[Claims] (1) A wet microporous layer of polyurethane resin is laminated and integrated on at least one side of the base material, and a polyurethane resin layer containing fine gelatin powder is further laminated and integrated on the surface thereof, and then fine gelatin powder in the polyurethane resin layer is formed. A synthetic leather characterized by having a porous skin layer made by dissolving and removing the skin. (2) After coating a solution of a polyurethane resin in a water-miscible organic solvent on at least one side of the substrate, it is immersed in water to remove the solvent and coagulate the polyurethane to form a wet microporous layer of the polyurethane resin; After forming a polyurethane resin layer containing fine gelatin powder on its surface, the laminate is immersed in hot water to dissolve and remove the fine gelatin powder, thereby forming a porous skin layer. Method of manufacturing leather. (3) In the method for producing synthetic leather according to claim 2, the laminate having a polyurethane resin layer containing fine gelatin powder is immersed in hot water and subjected to a rubbing treatment to dissolve and remove the fine gelatin powder; A method for producing synthetic leather, characterized by forming a porous skin layer. (4) In the method for producing synthetic leather according to claim 2, the laminate having a polyurethane resin layer containing fine gelatin powder is immersed in hot water and squeezed with nip rolls to dissolve the fine gelatin powder. A method for producing synthetic leather, which comprises removing the skin and forming a porous skin layer. (5) The method for producing synthetic leather according to claim 3, characterized in that the rubbing treatment is performed using a jet dyeing machine.