JPH0529711B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a unique color changeable artificial leather and a method for producing the same, and more specifically to artificial leather (including synthetic leather) used for clothing, shoes, sandals, belts, patchwork, and others. The present invention relates to an artificial leather whose color tone can be easily changed, and a method for manufacturing the same.

[Technical background of the invention]

Artificial leather is basically made by laminating a foam resin layer such as polyurethane resin on a base fabric, and forming a colored layer on this foam resin layer.

As is clear from its structure, the color tone of such artificial leather is determined by the colored layer, and conventionally it has been impossible to change the color density and tone.

In view of these circumstances, we formed a polyurethane resin layer on the base fabric, and then laminated a colored layer whose main component is a special polyurethane resin containing metal chlorides on this foam layer to create a color with a higher density than a light color. Artificial leather that can change color has been developed. The above-mentioned artificial leather has a transparent polyurethane resin as its main component, and is produced by applying heat and pressure to a colored layer in which a coloring agent is dispersed in the polyurethane resin.
The transparent polyurethane resin of the colored layer was changed to brown, and the original color of the colored layer (the color of the coloring agent) was deepened. In other words, the colored layer has a color that is a combination of the color of the colored polyurethane resin and the color of the colorant, but by mixing the color of the colorant layer and the brown, the original color of the entire colored layer is changed to a deeper color. It was hot.

Therefore, in the above-mentioned artificial leather, it is only possible to change the shade of the original color of the colored layer itself, but it is impossible to change the tone of the colored layer itself, and its uses are limited. It had the disadvantage of becoming

[Summary of the invention] The present invention has been made in view of the above points, and
An object of the present invention is to provide a color-variable artificial leather that can change the color tone of the artificial leather, and a method for producing the same.

Therefore, the different color changeable artificial leather according to the present invention is provided with a polyurethane foam layer and a colored layer on a base fabric, and a layer with a thickness of 100 to 500 μm and a porosity of 0.3 to 0.7 g/cm ³ on the colored layer. It is characterized by having a porous polyurethane coating film.

In addition, the method for producing a variable color artificial leather according to the present invention includes sequentially laminating a polyurethane foam layer and a colored layer on a base fabric, and a polyurethane emulsion containing polyurethane particles with an average particle size of 0.5 to 5 μm on the colored layer. Apply the liquid at a rate of 200 to 1000g/ ^m2 ,
Characterized by drying.

According to the present invention, since a porous polyurethane sheet is further laminated on top of the normal artificial leather,
By applying heat and pressure to this porous polyurethane sheet, the white porous polyurethane sheet containing air loses its pores and changes into a non-porous layer. As mentioned above, since non-porous polyurethane is transparent, the underlying colored layer becomes visible, which causes the coloring of the artificial leather to change.

[Specific description of the invention]

The artificial leather according to the present invention is made by laminating a foam layer and a colored layer on a base fabric, laminating a porous polyurethane sheet on this colored layer, and laminating a waterproof surface layer on this porous polyurethane sheet. ing.

In the present invention, the base fabric is not limited, and may be, for example, a woven fabric, a nonwoven fabric, a knitted fabric, or the like.

The foam layer laminated on the base fabric is preferably a polyurethane foam layer in consideration of the peel strength with respect to the colored layer laminated on the foam layer.

A colored layer is laminated on this foam layer,
This colored layer needs to have good adhesion to the aforementioned foam layer and the porous polyurethane sheet laminated to this colored layer, so it is preferably the same or of the same type as the porous polyurethane sheet or foam layer. It is preferable that the main component is a polyurethane resin with an appropriate amount of coloring agent added thereto.

Polyurethane resins used in such foamed layers and colored layers include, for example, diphenylmethane-4,4'-diisocyanate and diphenyl-dimethylmethane-diisocyanate as the isocyanate component.
4,4'-diisocyanate, phenylene-1,
4'-diisocyanate, 2,2',6,6'-tetramethyl-diphenylmethane-4,4' diisocyanate, diphenyl-4,4'-diisocyanate or alkyl, alkoxy or halogen derivatives of the above isocyanates, toluylene-2,4 - and 2,6-diisocyanate or mixtures thereof, 2,4-diisopropylenephenylene-1,
One or more types of 3-diisocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate and α, α, α', α'-tetramethyl p-xylylene diisocyanate and all kinds of polyester polyols and polyethers as the polyol component. Mention may be made of polyurethane resins which are polymers with one or more polyols. It is also possible to use a water-in-oil polyurethane emulsion that is preferably used when manufacturing a porous polyurethane sheet to be described later.

The coloring agent added to the polyurethane resin liquid when producing the colored layer is not fundamentally limited in the present invention, and a coloring agent of a desired color can be used. Such coloring agents include
For example, the water-in-oil polyurethane mixed with 10 to 40% by weight of inorganic and organic pigments can be used.

Furthermore, the amount of such a colorant added is preferably 0.3 to 3.0 parts by weight per 100 parts by weight of the polyurethane resin. Less than 0.3 parts by weight,
There is a risk that sufficient coloring ability will not be exhibited, and
If it exceeds 3.0 parts by weight, the color tone of the base coloring will change significantly, making it difficult to meet the user's requested color, and the tone will tend to be variable in the same color instead of different colors.

The porous polyurethane sheet to be laminated on such a colored layer may be any porous polyurethane sheet as long as it loses pores and becomes transparent under heat and pressure loads. Such a porous polyurethane sheet becomes transparent when the voids are reduced or eliminated by applying heat and pressure. The heat softening temperature is preferably 160 to 200°C. If the temperature is lower than 160°C, there is a risk that the color cannot be changed with good controllability, whereas if it is higher than 200°C, the color cannot be changed by household appliances such as an iron, and there is a risk that it will not be practical.

Further, as described above, if the porous polyurethane sheet has too many pores, it will be difficult to become transparent, whereas if the porous polyurethane sheet has too few pores, it will become less cloudy and the underlying colored layer will become visible. Therefore, the porosity of the porous polyurethane sheet is 0.3 to 0.7 g/cm ³
must be within the range.

Furthermore, the average size of the pores is preferably 2 to 2.
The thickness is preferably 10 μm. The average size of the holes is 2μ
If the average size is less than m, it may become difficult to produce a porous polyurethane sheet;
When it is larger than 10 μm, the strength between porous layers decreases, which may cause practical problems.

Porous polyurethane resins that meet these conditions include porous polyurethane obtained by drying a water-in-oil polyurethane emulsion consisting of hydrophobic polyurethane, hydrophilic polyurethane, an organic solvent, and water. The sheet can be mentioned (Special Publication No. 59-33611). That is, the above-mentioned hydrophobic polyurethane is obtained by reacting a hydrophobic polyol, an organic diisocyanate, and a chain extender in an organic solvent in which the resulting polyol is substantially insoluble and has a limited mutual solubility with water. contract
It is a hydrophobic polyurethane dispersion of particles with a size of 0.5 to 5 μm, and the hydrophilic polyurethane is a polyurethane containing polyoxyethylene groups in an amount of about 20 to 40% by weight of the total amount of the polymer, and the hydrophobic polyurethane and the hydrophilic polyurethane are The weight ratio is about 90-99: approx.
It can be a porous polyurethane sheet produced by drying a water-in-oil polyurethane emulsion having a molecular weight of 10 to 1.

Examples of the hydrophobic polyol used in the hydrophobic polyurethane include polyethylene adipate, polyethylene adipate, polyethylene butylene adipate, polydiethylene adipate, and polybutylene having a hydroxyl group as an end group and a molecular weight of 300 to 4000. Adipate, polyethylene succinate, polybutylene succinate, polyethylene sebacate, polybutylene sebacate, polytetramethylene ether glycol, poly-ε-caprolactone diol, polyhexamethylene adipate, carbonate polyol, polypropylene glycol, etc. Organic diisocyanates include 4,4'-diphenylmethane diisocyanate (MDI), water-added MDI, isophorone diisocyanate, 1,3
-xylylene diisocyanate, 1,4-xylylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate,
Examples include 1,5-naphthalene diisocyanate, m-phenylene diisocyanate, and P-phenylene diisocyanate. Furthermore, as chain extenders, ethylene glycol, propylene glycol, diethylene glycol, 1,4-
Butanediol, 1,6-hexanediol, ethylenediamine, 1,2-propylenediamine,
Examples include trimethylene diamine, tetramethylene diamine, hexamethylene diamine, decamethylene diamine, isophorone diamine, m-xylylene diamine, hydrazine, and water.

Polyurethane particles produced from such a hydrophobic polyol, an organic diisocyanate, and a chain extender have an average particle size of 0.1 to 5 μm.

Furthermore, the hydrophilic polyurethane is prepared in the same manner as the above-mentioned hydrophobic polyurethane except that a part of the above-mentioned hydrophobic polyol is replaced with polyethylene glycol or its equivalent.
Such hydrophilic polyurethane is added to improve the dispersibility of the hydrophobic polyurethane,
The hydrophobic polyurethane and the hydrophilic polyurethane are dissolved in the organic solvent at a weight ratio of 90-99:10-1. This is because if the above-mentioned compounding ratio is exceeded, good dispersion stability of the polyurethane particles cannot be obtained. In addition, the amount of polyoxyethylene groups in this hydrophilic polyurethane is 20 to 40% by weight,
This is because if it deviates from this range, good dispersion stability will be impaired.

Organic solvents used for such hydrophobic polyurethane particles and hydrophilic polyurethane include methyl ethyl ketone, methyl-n-propyl ketone, methyl isobutyl ketone, diethyl ketone, methyl formate, ethyl formate, propyl formate, methyl acetate, and ethyl acetate. , butyl acetate, etc. Also used are acetone, cyclohexane, tetrahydrofuran, dioxane, methanol, ethanol, isopropyl alcohol, butanol, toluene, xylene, dimethylformamide, dimethyl sulfoxide, perchloroethylene, trichlorethylene, methyl cellosolve, cellosolve acetate, etc. can.

Of course, it is clear that the present invention is not limited to porous polyurethane sheets produced from such polyurethane resins.

The thickness of the above porous polyurethane sheet is
It is 100 to 500 μm. If it is less than 100 μm, there is a risk that the underlying colored layer will be visible through it, and there is also a risk that peel strength cannot be ensured.
If it exceeds 500 μm, it may take a long time to become transparent even if heat and pressure are applied.

Next, a method for producing a different color variable artificial leather according to the present invention will be explained.

First, a polyurethane foam layer is formed on a base fabric. For producing such a polyurethane foam layer, all conventional methods for producing this type of artificial leather can be effectively used. For example, it may be artificial leather manufactured by either a wet method or a dry method.

Although a colored layer is provided on such artificial leather, the method for producing such a colored layer is not limited in the present invention, and conventional methods can be used.

Now, a porous polyurethane sheet is laminated on such a colored layer, but the method of laminating such a porous polyurethane sheet is basically not limited. For example, it can be produced by coating the water-in-oil polyurethane emulsion described above by a method such as a roll-on knife and drying. When manufacturing a porous polyurethane sheet by coating and drying such a water-in-oil polyurethane emulsion, preferably the concentration of the polyurethane resin component is 10 to 20% by weight and the viscosity is 5.0 to 10.0 cps.
Prepare a polyurethane emulsion so that the temperature is (25℃). If the polyurethane resin content is less than 10% by weight, the porosity and strength may decrease, and if it exceeds 20% by weight, it becomes difficult to form porosity.

Furthermore, if the viscosity is out of the above range, it will be difficult to apply the polyurethane emulsion to the colored layer.

The amount of such polyurethane emulsion applied is limited by the thickness of the porous polyurethane sheet mentioned above. Therefore, the amount of application is 200 to 1000g/
m ² (wet amount). This is because if it deviates from the above range, there is a risk that a porous polyurethane sheet with the desired thickness may not be obtained.

The average size of the pores in the porous polyurethane sheet described above is governed by the size of the polyurethane resin particles dispersed in the polyurethane emulsion. Therefore, the average particle size of this polyurethane resin particle is 0.1
~5μm. If it is smaller than 0.1 μm, the pore size of the porous polyurethane sheet becomes too small.
There is a risk that the white turbidity will be thin and the colored layer underneath will be visible.On the other hand, if it is larger than 5 μm, the pore size of the porous polyurethane sheet will become too large, and the strength between the porous layers will decrease, which may cause practical problems. be.

After the polyurethane emulsion is applied in this manner, it is dried to produce a polyurethane sheet having many voids, that is, a porous polyurethane sheet.

This drying can be done in one step, but
In order to form pores that are uniformly dispersed and have good controllability, it is preferable to perform preliminary drying and then perform main drying.

This preliminary drying is preferably carried out at a temperature of 67 to 80°C for 3 to 5 minutes. Pre-drying temperature is 67℃
If it is less than 20%, gelation time will be longer and productivity
There is a risk that workability will deteriorate, and if the temperature exceeds 80°C, variations in porosity will increase, causing strength or surface unevenness, and quality may deteriorate.
Furthermore, if the pre-drying time is less than 3 minutes, there will be no sufficient pre-drying effect, and if it exceeds 5 minutes, problems may arise in productivity and workability.

After laminating the porous polyurethane sheet on the colored layer in this manner, a surface layer is optionally formed.
This surface layer is provided to prevent water from entering the porous polyurethane sheet and to decorate the surface, and is mainly composed of polyurethane resin to ensure good peel strength and transparency. It is something. This polyurethane resin may be the polyurethane resin used in the above-mentioned porous polyurethane sheet or the polyurethane resin used in the colored layer.

This surface layer can be manufactured by coating a porous polyurethane sheet by gravure processing or the like and drying it. When the surface layer is formed by coating as described above, the polyurethane resin concentration of the polyurethane resin liquid is preferably 5 to 10% by weight. If it is less than 5%, there is a risk that a surface layer with sufficient strength and waterproofness may not be obtained;
This is because if it exceeds 10%, there is a risk that economical efficiency and workability will deteriorate.

Further, the coating amount is preferably 15 to 25 g/m ² (wet amount). If it is less than 15 g/m ² , there is a risk that a surface layer with sufficient strength and waterproofness may not be obtained, while if it exceeds 25 g/m ² , there will be problems in economic efficiency.

Furthermore, drying is preferably carried out at a temperature of 120 to 130°C for 2 to 3 minutes. When the drying temperature is less than 120℃,
There is a risk that a sufficient surface layer may not be obtained;
If it exceeds this, there is a risk that the quality of the surface grains etc. will deteriorate. If the drying time is less than 2 minutes, there is a risk that a surface layer will not be obtained, and if it exceeds 3 minutes, it will be economically disadvantageous.

The unique color variable artificial leather produced in this way can be produced by applying pressure at a temperature near the softening point.
The area where heat and pressure are applied becomes transparent and the color of the artificial leather changes.

Examples will be described below.

Example A polyurethane foam layer was formed on a base fabric, and a polyurethane resin liquid having the following composition 1 was applied thereon and dried to form a colored layer.

Composition 1 Polyurethane resin (Gronlac Medium)
Lu1632: Dainippon Ink Co., Ltd.) 100 parts by weight MEK 40 parts by weight Colorant (Dairatsu TV Color: Dainippon Ink Co., Ltd.)
Coat 30 parts by weight of a polyurethane resin solution having the following composition 2 on this colored layer at a rate of 400 g/m ² and heat it at a temperature of 70°C.
After pre-drying for a minute, main drying was further carried out at a temperature of 100° C. for 3 minutes.

Composition 2 Polyurethane resin (particle size 2 μm) (Heimlen X-
385: Manufactured by Dainichiseika Chemical Co., Ltd.) 100 parts by weight MEK 18 parts by weight Toluene 18 parts by weight Water 30 parts by weight To the porous polyurethane sheet structured as above, 20 g of polyurethane resin liquid of the following composition 3 was added / Apply at a rate of ³ m2 and at a temperature of 120°C.
A surface layer was formed by drying for minutes.

Composition 3 Polyurethane resin (Hicorp U-19 20 parts by weight,
Hicorp u-31M 80 parts by weight: All special colorants
Co., Ltd.) 100 parts by weight DMF 10 parts by weight MEK 10 parts by weight Toluene 40 parts by weight When the artificial leather thus produced was subjected to a pressure of 20 kg/cm ² at a temperature of 160°C or higher, it became porous. The polyurethane sheet was compressed and became transparent, making the colored layer underneath the polyurethane sheet visible and changing the color of the artificial leather.

Claims (1)

[Claims] 1. A polyurethane foam layer and a colored layer are provided on a base fabric, and a porous polyurethane coating film with a thickness of 100 to 500 μm and a porosity of 0.3 to 0.7 g/cm ³ is provided on the colored layer. Unique color changeable artificial leather characterized by: 2. A polyurethane foam layer and a colored layer are sequentially laminated on the base fabric, and a polyurethane emulsion containing polyurethane particles with an average particle size of 0.5 to 5 μm is applied onto this colored layer at a rate of 200 to 1000 g/ ^m2. ,
A method for producing a unique variable color artificial leather characterized by drying.