JPS5916030B2 - Method for manufacturing leather-like sheets with rich color changes - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a leather-like sheet that has a luxurious feel and is rich in color change.

Leather-like sheets are used as an alternative to natural leather for shoes, poles,
Widely used for bags, clothing, interior materials, etc.

Conventionally, the color of the surface of the leather-like sheet was relatively uniform and flat, but recently, three-dimensional colors with a rich variety of colors have become more popular because they have depth and look more luxurious.

Currently, the most commonly used methods for coloring such leather-like sheets are spraying or using a roll (pattern plate) engraved with a certain pattern to create different shades of color.

However, the spray method has drawbacks such as low productivity, difficult work, and the need for a high degree of skill.Also, the gravure printing method, which uses a roll engraved with a certain pattern, produces a leather-like sheet with a color that is There were drawbacks such as the uniformity of the color and pattern making it impossible to match individual tastes, and the difficulty in creating the desired color or pattern in the desired location of a top-quality product, all of which were unsatisfactory. .

In addition to the above, a method has been proposed in which a composition comprising nitrocellulose and a pigment is used as a finishing agent.

This method has the advantage of good workability and the ability to create different shades of color anywhere on the final product, but in order to obtain one type of leather-like sheet, color adjustment must be carried out twice: on the base layer and on the outermost surface. However, as a result of wasting a lot of time on these, there was a drawback that it was not possible to produce many brands in small quantities.

Furthermore, the leather-like sheet obtained by this method also has the disadvantage of poor bending resistance and abrasiveness, so this method is rarely used at present.

Therefore, as mentioned above, it has been a major challenge for those concerned to obtain a leather-like sheet that is free from defects, unique, luxurious, and rich in color variation.

As a result of extensive research into finishing agents and finishing methods, the present inventors applied a polymer having good affinity with the coating layer to the surface of a substrate consisting of a fibrous material and a coating layer, and then
Two or more colorants with different migration properties, plasticity and degree of nitrification (
V) Apply a resin solution containing cellulose nitrate with a weight factor of 9.5 to 13.0, and then heat at 70°C to 250°C.
By heat-treating the sheet and then removing a part of the outermost layer with an abrasive, it is possible to obtain a unique leather-like sheet that has no defects as described above, has a rich color change, and has a luxurious feel. I found it.

In other words, one of the objects of the present invention is to create a leather-like product that has excellent performance such as bending resistance and abrasiveness, and that has a high-quality, unique leather-like appearance that has a rich color change that has the desired shade of color in the desired place of the final product. An improved method of obtaining sheets is provided.

Another object of the present invention is not only to omit the color adjustment of the base, but also to produce products with a wide variety of colors by appropriately selecting the color of the outermost resin layer, heat treatment conditions, and degree of polishing. The present invention provides a method for producing leather with good workability and productivity, and for the first time, leather 7 with high commercial value can be produced.
It is now possible to produce a large number of different types of sheets in small quantities and in many brands.

The fibrous material in the present invention is a sheet-like material mainly composed of fibers such as nonwoven fabrics, woven fabrics, and knitted fabrics, and is optionally impregnated with and coagulated with a polymer as a binder.

The fibers that can be used include ordinary fibers such as cotton, hemp, wool, rayon, acetate, nylon, polyester, polyacrylonitrile, vinylon, polyethylene, etc., as well as their mixtures or composite spun fibers. Any fiber can be used.

As the binder optionally added to the above-mentioned fibrous material, any binder generally used for synthetic leather etc. can be used, such as natural rubber, styrene-butadiene copolymer, acrylonitrile-butadiene copolymer. , nylon, polyacrylic acid resin, polyvinyl chloride,
Polyurethane elastomers, other synthetic rubbers, or mixtures thereof are used.

These binders are applied in a solution, emulsion, or other form as required by an impregnation method, a coating method, a spray method, etc., and the amount of adhesion is usually in the range of 150% by weight or less based on the fibers.

A coating layer is formed on one side of the fibrous material thus obtained.

The coating layer corresponds to the silver surface of natural leather, and preferably has a porous structure from the viewpoint of texture, creases, physical properties, etc.

For the coating layer, polyurethane elastomer, polyvinyl chloride, nylon, polyamino acid resin, etc. are used.

Among these, polyurethane elastomers are particularly preferred because they can easily form a porous structure and have good scratch resistance, bending resistance, and texture.

The polyurethane elastomer has a molecular weight of 500 to 400.
Soft segments such as 0 polyethylene glycol, polytetramethylene glycol, polyethylene adipate glycol, polyhexamethyladipate glycol, polycaprolactone glycol, etc. and ethylene glycol, butanediol, hexanediol, ethanolamine, hydrazine, 4,4'-methylene bis (2-chloroaniline) and other chain extenders and diphenylmethane-4,4'-
It consists of incyanates such as diisocyanate, tolylene diisocyanate, and hexamethylene diisocyanate.

The polyurethane elastomer preferably has appropriate hardness in terms of heat resistance, surface strength, bending resistance, tactility, etc., and usually has a nitrogen content of 3% to 7% by weight based on diisocyanate.

The polyurethane elastomer contains fillers, pigments, softeners, stabilizers, antistatic agents, gloss modifiers, etc., as well as polymers with good compatibility in the solution state, such as polychloride, vinyl, polyvinyl acetate, polyvinyl formal, etc. polyacrylic acid resin,
A copolymer of vinylidene chloride and acrylonitrile, a copolymer of vinyl chloride and vinyl acetate, etc. can be mixed as necessary.

The method of applying the polymer solution to the fibrous material is preferably a coating method or a spray method, but it is also possible to prepare a separate coating layer and bond it together.

A polymer layer is applied onto the coating layer of the substrate thus obtained.

Any polymer can be used as long as it has good affinity with the coating layer, but polyurethane elastomer is particularly preferred.

The coating amount of the polymer is 0.2g/m2 to 10f in terms of solid content!
/7i is appropriate.

Various additives including colorants can be mixed into the polymer layer according to preference.

Then, a resin solution containing two or more colorants having different migration properties, a plasticizer, and cellulose nitrate having a degree of nitrification (V) of 9.5 to 13.0 by weight is applied.

The two or more colorants having different migration properties used in the present invention can be selected from dyes and/or pigments, and the difference in the amount of colorants migrated under the heat treatment conditions of the present invention results in color migration. at least 10% of each other based on the total weight of the agent
They differ by more than 50 weight factors, preferably by 50 weight factors or more,
Among these, it is preferable to use one or more types of dyes as colorants with high migration properties and one or more types of pigments as colorants with low migration properties.

Usually, this combination fully satisfies the conditions of the present invention since the pigment hardly migrates.

In particular, the combination of a gold-containing complex dye and an organic pigment is the best in terms of light resistance and color clarity.

The composition of the coloring agent will of course vary depending on the desired base and surface color, but it will also be greatly influenced by the transferability of the colorant used and the conditions of the subsequent heat treatment.

The appropriate amount of the coloring agent to be used is 5% to 300% by weight based on the resin, taking into account the color feel, adhesion to the coating layer, bending resistance, etc.

Commonly available plasticizers include tricresyl phosphate, triphenyl phosphate, trichloroethyl phosphate, dibutyl tucrate, dioctyl phthalate, butyl phthalyl butyl glycolate,
In addition to polyvinyl methyl ether, ethyl abietate, triacetin, etc., olive oil, castor oil, coconut oil, palm oil, linseed oil, cottonseed oil, powdered whale oil, cow leg oil, etc., or sulfated or epoxidized products thereof are used. .

The amount of plasticizer used depends on bending resistance, texture, migration properties, abrasiveness,
From the viewpoint of surface strength and the like, a ratio of 20% to 250% by weight relative to the resin is appropriate.

Further, as mentioned above, the degree of nitrification (2) of cellulose nitrate is preferably in the range of 9.5 to 13.0 by weight because common paint solvents can be used and abrasive properties are good.

Solvents used to prepare the resin solution include acetone, ethyl acetate, butyl acetate, methyl ethyl ketone, methyl butyl ketone, methanol, butanol, benzene, toluene, xylene, dimethylformamide, dimethylacetamide, and the like.

It is more advantageous in terms of productivity to apply the resin solution by gravure printing than by spraying.

The coating amount of the resin solution is desirably 0.2 g/m2 to 109/m2 in terms of solid content in terms of productivity, color feel, bending resistance, abrasiveness, etc.

Further, the surface of the resin layer is heat-treated at a temperature of 70°C to 250°C.

When the heat treatment temperature is below 70°C, there is little migration of the dye to the base, whereas when it is above 250°C, decomposition of cellulose nitrate and polyurethane elastomer occurs,
The porous structure of the base layer may be destroyed, resulting in poor texture, bending resistance, etc.

The heat treatment time is determined by the treatment temperature and the desired color of the base, but it is usually 2 seconds to 2 seconds from the viewpoint of productivity and reproducibility.
Approximately 30 minutes is desirable.

In addition, the heat treatment can be performed either under pressure or under pressure. When heat treatment is performed under pressure, the desired shape can be achieved by using an embossing roll or embossing plate with an arbitrary pattern. Pushing is also possible.

Finally, before or after making any final product, such as a bag, clothing, etc., a portion of the outermost layer at the desired location is appropriately removed with an abrasive to create the desired pattern or color.

The leather-like sheet thus obtained has a colored base partially visible due to the colorant transferred from the surface resin layer, giving it an antique look and a very high-class feel.

Furthermore, according to the present invention, by appropriately selecting the colorant composition of the outermost resin layer, the heat treatment conditions, and the degree of polishing, it is possible to easily manufacture products in many colors, and it is also possible to produce products in small quantities and in many brands.

The present invention will be described below with specific examples.

Note that all references in the examples are based on weight.

Example 1 Polycaprolactone glycol, diphenylmethane-4
, 15% polyurethane elastomer synthesized from 4'-diisocyanate and ethylene glycol, polyvinyl chloride 2 candy, pink pigment (manufactured by Inu Nisseika Kogyo KK: N-1)
65 Red) 0.3 and dimethylformamide 82.
A nonwoven fabric of nylon fibers is impregnated with a solution consisting of 7%, and the same solution as above is applied on top of it at a solid content of 100 El/@'
The substrate was coated so as to have the following properties and then immersed in an aqueous solution containing 145% dimethylformamide at 45° C. for 30 minutes to solidify, followed by solvent removal and drying to produce a porous substrate.

Then polyethylene glycol, diphenylmethane-4
, 4'-diisocyanate and ethylene glycol)? After applying a solution consisting of -6 parts, dimethylformamide part 22 parts, acetone part 32 parts, and cyclohexanone 40070 to a solid content of L5 g/m2 using the gravure printing method, the degree of nitrification (V)
12.5% cellulose nitrate 6.5%, dibutyl phthalate 6.5% Lany IViolet 4 B (manufactured by Sumitomo Chemical KK) 1.0%, phthalocyanine blue pigment (manufactured by Inu Nisseika KK) 1.3 Person in charge, toluene 35.0
A solution consisting of 49.7 parts of ethyl acetate and 49.7 parts of ethyl acetate was added to
It was applied by gravure printing to a coating thickness of 9/m2, and after drying, a rough pattern was embossed at 165° C. for 30 seconds.

When men's shoes were made from the obtained leather-like sheet A and the outermost layer was removed at an arbitrary location using an abrasive, the dye in the outermost colored layer was transferred to the underlying clear layer, and the color of the underlying layer was changed. It was a high-quality product with a very rich color change that was partially visible.

Furthermore, since the leather-like sheet A was color-adjusted only once, it had better productivity and lower manufacturing cost than conventional two-time color-adjusted products.

On the other hand, only the stamping conditions are 140°C for 30 seconds and 1
Leather-like sea 1-
B and C were manufactured.

These leather-like sheets are all the above-mentioned leather-like sheets A.
When these sheets were made and polished in the same manner as above, the base of a different color from the leather-like sheet A was partially visible and the color changed significantly. It was a high-quality product that we collaborated with.

Example 2 Polyethylene adipate glycol and diphenylmethane-4,4 were placed on a polyethylene sheet embossed with a foreign pattern.
A solution consisting of 12% polyurethane elastomer synthesized from '-diisocyanate and 1,4-butanediol, 2 parts titanium oxide, and 86 parts dimethylacetamide was applied to a solid content of 609771J, and a solution containing 30 parts dimethylacetamide was applied. After treatment with an aqueous solution at .degree. C. for 30 minutes, solvent removal, drying, and peeling from the polyethylene sheet were performed to produce a porous film.

Next, a woven fabric of raised polyester fibers was adhered to the coagulated surface side of the porous film, and on top of this was added 7% of the same type of polyurethane elastomer as the porous film and 0.4% of an azo yellow pigment (Inu Nisseika Kogyo KK). %, dimethylacetamide 28%, tetrahydrofuran 39.6% and cyclohexanone 25% solid content 3.6g
/m2 After application, nitrate cellulose with a nitrification degree (N) of 10.2
．． 8%, 3 parts dioctyl phthalate, 1 part castor oil, L
anyl Brown3 R (manufactured by Sumitomo Chemical Industries KK) 2
．． After applying a solution consisting of 2% carbon black, 2 parts carbon black, 42% toluene, and 45 parts methyl ethyl ketone, heat treatment was performed at 90° C. for 6 minutes.

A women's bag was made from the obtained leather-like sheet 1-D, and the outermost layer at any location was removed in the same manner as in Example 1, and the dye in the outermost colored layer was found to have migrated to the base layer. It was a high-quality product with a rich color variation that partially showed the underlying color.

The manufacturing cost of the leather-like sheet 1-D was also much lower than that of conventional products.

Furthermore, by simply changing the heat treatment conditions, a large number of products with colors different from the leather-like sheet D described above were produced very easily.

All of these, like leather-like sheet D, had very high commercial value.

Claims (1)

[Claims] 1. After a polymer having good affinity with the coating layer is applied to the surface of a substrate consisting of a fibrous material and a coating layer, two or more colorants having different migration properties, a plasticizer and Nitrification degree (V)9.
It is characterized by applying a resin solution containing cellulose nitrate of 5% to 13.0% by weight, heat-treating at 70°C to 250°C, and then removing a part of the outermost layer with an abrasive. A method for producing a leather-like sheet that has a luxurious feel and a rich color change. 2. The method for producing a leather-like sheet according to claim 1, wherein a pigment and a dye are used as two or more colorants having different migration properties. 3. The method for producing a leather-like sheet according to claim 1, wherein an organic pigment and a metal-containing complex dye are used as two or more colorants having different migration properties. 4. A method for producing a leather-like sheet according to claim 1, wherein a nonwoven fabric impregnated with an elastic polymer is used as the fibrous material. 5. The method for producing a leather-like sheet according to claim 4, in which a porous elastic polymer is used for the fibrous material and/or the coating layer. 6. The method for producing a leather-like sheet according to claim 1, wherein a polyurethane elastomer is used as the fibrous material, the covering layer, and the polymer having good affinity with the covering layer. 7. A method for producing a leather-like sheet according to claim 1, wherein the coating layer is colored and/or stamped.