JPS605709B2 - Method for producing leather-like sheets with excellent valley dyeing effect - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a leather-like sheet with excellent valley dyeing effect.

More specifically, the present invention provides a surface of a substrate having an uneven pattern,
The present invention relates to a method for producing a leather-like sheet with excellent graininess by applying a colored polymer mainly to the concave portions using a special roll using a gravure printing method. Leather-like sheets, in which the base material is colored and embossed, are widely used as substitutes for natural leather in all fields such as shoes, bags, cases, balls, clothing, and interior materials. In order for the leather-like sheet to be used in such a wide variety of fields, it goes without saying that it must have excellent physical properties and texture to suit each application, but it must also have excellent surface color and texture. The pattern also greatly influences the value of the product. In particular, as fashion becomes more and more popular today, improvements in appearance, that is, higher quality finishes, are strongly discouraged. In response to such demands, currently widely used finishing methods include applying color shading by spraying or by using a gravure roll engraved with a certain pattern.
However, these methods simply apply color shading on the same plane, resulting in a lack of three-dimensional color impression, and the former method has poor productivity and does not result in a fully satisfactory product.
Therefore, it has been a major challenge for those involved to obtain a leather-like sheet with good workability and productivity and rich three-dimensional color appearance.
As a result of extensive research into finishing agents and finishing methods, the inventors of the present invention applied a colored polymer solution to the uneven surface of a substrate using a gravure printing method using a flat roll, and then dried it. By doing so, we have discovered that it is possible to obtain a leather-like sheet that is free from the above-mentioned drawbacks, has a very rich valley dyeing effect, that is, a three-dimensional color effect, and has a high commercial value, and has thus arrived at the present invention.

In other words, the present invention selectively colors only the concave portions of the uneven pattern on the surface of the substrate by using a flat roll without a conventional engraving instead of a roll with a conventional engraving. It has become extremely easy to obtain a leather-like sheet with rich color and a luxurious feel. The substrate in the present invention consists of a fibrous base material and a polymer coating layer, or consists of only a polymer.

The fibrous base material is a sheet-like material mainly composed of fibers such as nonwoven fabric, woven fabric, or knitted fabric, and if desired, it is impregnated and coagulated with a polymer as a binder. As the fibers used, ordinary fibers can be used, such as cotton,
Not only single paper yarn fibers such as hemp, wool, rayon, acetate, nylon, polyester, polyacrylonitrile, vinylon, and polyolefin, but also mixtures thereof, composite spun fibers, etc. can be used. As the binder optionally added to the above-mentioned fibrous base material, any binder that is generally used for synthetic leather etc. can be used, such as natural rubber, styrene-dadiene copolymer, acrylonitrile-rubin, etc. Budadiene copolymer, methyl methacrylate-butadiene copolymer, polyvinyl chloride, polyurethane, other synthetic rubbers, or mixtures thereof are used.

These binders are applied in the form of a solution, emulsion, or the like as required by an impregnation method, a coating method, or the like.
The amount of adhesion is usually within 150% of the fiber. A polymer coating layer is formed on one side of the fibrous base material thus obtained.

The coating layer corresponds to the grain surface of ordinary leather, and is preferably porous in view of texture, creases, physical properties, etc. Polymers include polyurethane and acrylonitrile-butadiene copolymer.
Examples include polyvinyl chloride, polyamide, etc., but polyurethane elastomer is particularly desirable. The polymer may optionally contain fillers, softeners, stabilizers, antistatic agents, pigments, dyes, blowing agents, coagulation regulators, etc., as well as polymers with good compatibility in the solution state, such as Polyvinyl chloride, polyvinyl acetate L
Polyvinyl formal, polyacrylic acid resin, vinylidene chloride-acrylonitrile copolymer, copolymer of vinyl chloride and vinyl acetate, etc. can be mixed. The preferred method for applying the polymer coating layer to the fibrous base material is a coating method, but it is also possible to separately prepare a polymer coating layer and bond it together.

Further, as the substrate of the present invention, a porous or non-porous sheet consisting only of the same kind of polymer as the above-mentioned coating layer can also be used.

The substrate may be suitably colored or may have another layer such as a clear layer on its surface.

Next, in the present invention, it is an essential condition that an uneven pattern exists on the surface of these substrates. If the surface of the substrate is flat without a pattern of protrusions and recesses, even if such a coloring method is used in the next step, a product with poor three-dimensional color impression cannot be obtained. Further, even in the case of a substrate having a shallow uneven pattern, it is difficult to obtain an excellent valley-to-beam feel, so the depth of the unevenness is preferably 50 mm or more, particularly 100 mm or more.

The uneven pattern is formed by stamping after the substrate is manufactured as described above. Alternatively, during the manufacture of the substrate, the surface portion thereof can be prepared on a support such as a release paper, a polyethylene sheet, or a metal plate having a desired uneven pattern.Finally, the characteristics of the present invention are as follows. A polymer solution containing a coloring agent is applied using a gravure printing method using a non-engraved flat roll to selectively color only the concave portions.

As the coloring agent, either dyes or pigments can be used. In addition, the hue of the coloring agent is selected as appropriate depending on the hue of the convex parts.It is better to color the concave parts in a purulent color rather than the convex parts, as it gives a more three-dimensional color, but depending on your preference, you can color the concave parts in a lighter color. It is also possible to do so. As for the flat roll, a roll with less unevenness will give better results, and a roll with almost no difference in unevenness, preferably 5 degrees or less, particularly 2 degrees or less, is advantageous for producing a valley-beam feeling.

When using a roll with an imprint of the substructure, only two-dimensional coloring corresponding to the imprint can be achieved, so the excellent valley dyeing effect produced by the synergistic effect of the coloring and the concave part of the base, that is, the three-dimensional color of the present invention, is possible. It is not possible to obtain products that are rich in taste and have high commercial value. Further, in the present invention, when coloring the substrate, the amount of the colored polymer solution applied to the flat roll is extremely important, and the amount must be sufficient to completely fill the recesses on the surface of the substrate.

Although the amount varies depending on the unevenness of the surface of the substrate, that is, the depth of the recesses, it is usually desirable to apply the colored polymer solution by depositing it on a flat roll for 20 days or more per coat. The amount of the colored polymer solution attached to the flat roll is adjusted by the concentration and viscosity of the colored polymer solution, the size of the flat roll, the rotation speed of the flat roll, etc. Furthermore, the color of the entire surface of the substrate or the color of the convex portions can be adjusted at any stage as necessary using a conventional coloring method.

The leather-like sheet obtained in the manner described above has different colors in the concave and convex portions, is extremely rich in valley-beam feel, that is, three-dimensional color sense, and has a very luxurious feel.

Furthermore, the present invention has made it possible for the first time to industrially and efficiently color and finish only the concave portions of continuous sheets of synthetic leather, etc., which is important in the production of sheets in this field. This is a groundbreaking achievement. The present invention will be specifically described below with reference to Examples. Note that all percentages in this example are based on weight. Example 1 A solution consisting of 20% polyurethane elastomer synthesized from polyethylene adibate glycol, diphenylmethane-4,4-diisocyanate and ethylene glycol, 2% brown pigment, 8% dibutyl phthalate and 70% dimethylformamide was applied to nylon. Impregnate a nonwoven fabric of fibers, apply the same solution as above so that the solid content is 140%, and then soak the 3 powders in an aqueous solution of 60°C containing 50% dimethylformamide to solidify. Thereafter, solvent removal and drying were performed to produce a porous substrate.

Next, a solution consisting of 6% of the same type of polyurethane elastomer as described above, 2% of InyYellow Station (manufactured by Sumitomo Chemical Industries KK), 28% of dimethylformamide, 32% of tetrahydrofuran, and 32% of cyclohexanone was applied to this surface in terms of solid content. 2 evenings/Applyed to finish. A leather-like sheet A was obtained by stamping the surface of the sheet with an embossing roll having a buffalo pattern to a depth of 187 peaks.
Additionally, 6% of the same type of polyurethane elastomer as above.
, LanyIYellow 3R2%, lrgalan
Black G B L (manufactured by Cygy)
A flat roll (mirror roll) with a surface unevenness difference of less than 1 F is a solution consisting of 1% dimethylformamide, 28% dimethylformamide, 31% tetrahydrofuran, and 32% cyclohexanone.
Leather-like sheet B was obtained by applying it to a part of leather-like sheet A and drying it for 240 minutes. Leather-like sheet B
The color of the protrusions was almost the same as that of leather-like sheet A, but the former had a flat color with no color difference between the protrusions and recesses, whereas the former had a flat color with no color difference between the protrusions and recesses. is big,
It had a very valley-like feel, an excellent three-dimensional color feel, and had extremely high commercial value. For comparison, a flat roll (mirror roll) was applied to the surface of the above leather-like sheet A.
A leather-like sheet C was obtained in the same manner as in the above example except that a conventional 200 mesh gravure roll (with a difference in unevenness of about 30 r) was used instead. Since the convex portions on the surface of the leather-like sheet C were also colored black, the leather-like sheet C had a much poorer valley feel than the leather-like sheet B. Example 2 8% polyurethane elastomer synthesized from polycaprolactone glycol, 1,4-butanediol, diphenylmethane-4,4'-diisocyanate, and After applying a solution consisting of 2% vinyl chloride, 2% red pigment (Red N-165: manufactured by Dainichiseika Kogyo KK) and 88% dimethylacetamide so that the solid content was 70%,
It was treated with an aqueous solution of 30q0 containing 30% dimethylacetamide for 30 minutes.

Claims (1)

[Scope of Claims] 1. By applying a colored polymer solution to the surface of a substrate having an uneven pattern using a gravure printing method using a flat roll with a surface unevenness difference of 2 μ or less, only the concave portions of the uneven pattern can be printed. A method for producing a leather-like sheet with excellent valley dyeing effect, which is characterized by coloring and drying. 2 Add 20g/m of colored polymer solution to flattrol
A method for producing a leather-like sheet according to claim 1, wherein the substrate is colored by attaching two or more of them. 3. The method for producing a leather-like sheet according to claim 1, wherein the depth of the uneven pattern on the substrate is 50 μm or more. 4. The method for producing a leather-like sheet according to claim 1, wherein the substrate comprises a fibrous base material and a coating layer. 5. The method for producing a leather-like sheet according to claim 1 or 4, wherein a porous elastic polymer is used as the substrate. 6. A method for producing a leather-like sheet according to claim 1, which uses a colored substrate as the substrate. 7
A method for producing a leather-like sheet according to claim 1, 4, 5 or 6, wherein a polyurethane elastomer is used as the substrate and other polymers.