JPH02251685A - Dyeing of artificial leather - Google Patents

Abstract

PURPOSE:To accomplish uniform dyeing of the subject leather by continuous dyeing of an artificial leather comprising a nylon nonwoven fabric containing urethane using a water based dyeing bath containing an acid dye, alcohol and penetrant. CONSTITUTION:A silver-coated artificial leather prepared by laminating a urethane-impregnated nylon nonwoven fabric or an artificial leather comprising said nonwoven fabric with a dyeable urethane skin is immersed in a dyeing bath prepared by adding pref. <=50wt.% of an aprotic polar solvent (e.g. dimethylamide) to a composition comprising an acid dye or metal-contg. dye, alcohol (accounting for >=20wt.% of the final dyeing bath), penetrant and water to carry out continuous dyeing to effect the objective uniform dyeing into the nonwoven fabric in a short time. For said penetrant, the amount to be used is preferably such as to be <=10sec. in the penetrating time when 0.01cc of a dyeing bath droplet is dripped from a height of 5cm to the dyeing bath.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for dyeing artificial leather, and more particularly to a continuous dyeing method for artificial leather containing a urethane-impregnated nylon nonwoven fabric.

[Conventional technology]

Traditionally, as a manufacturing method for artificial leather or synthetic leather with a silver surface, a pigment-colored urethane skin layer is formed on release paper that provides various grains, then an adhesive layer is coated, and urethane-impregnated polyester or nylon is coated. Methods of bonding nonwoven fabrics made of ultrafine threads and various woven or knitted fabrics have been implemented.

On the other hand, as a way to increase the product value by creating a natural feel similar to natural leather, such as a clear hue that cannot be obtained with pigment coloring, a transparent window, and a three-dimensional effect due to the density difference between the peaks and valleys of the grain, we have developed a method to increase product value. Produced as a white fabric using urethane that can be piece-dyed, acid dye or 1.2
- A method of piece-dying with metal-containing dyes has been developed.

In the field of artificial leather, there are suede-like artificial leather, which is made by impregnating a nonwoven fabric made of ultrafine nylon or polyester threads with several tens of weight percent urethane and grinding the surface, and bank artificial leather, which is made by laminating a urethane skin on this material. There is. By combining such an artificial leather base fabric with the above-described dyeable urethane skin, high-grade artificial leather with distinctive color and texture can be obtained.

[Problem to be solved by the invention]

However, in this dyeing method for dyeable artificial leather, the skin of a long object is dyed to a uniform color density and hue;
It is difficult to obtain a dyed product that penetrates into the inside of the nonwoven fabric.
At present, no practical staining method has been established. For example, in the method using a Zucker-type dyeing machine, acid dyes or 1.2-metal-containing dyes are quickly dyed on the dyeable urethane skin, which tends to cause problems with endings, such as concentration differences in the longitudinal direction, and tension in the longitudinal direction. The width becomes narrower due to
In the case of urethane-impregnated nylon nonwoven fabrics, which are prone to dyeing spots, the dyeing bath is not replaced in the thickness direction, and only the surface of the nonwoven fabric is dyed. Therefore, when molded into shoes, there are problems such as a white cut cross section and low commercial value.

Continuous dyeing methods that use water-based hot water have problems such as it is difficult to control the dye density and hue in the longitudinal direction at a constant level, and the dyeing speed is slow, requiring a large capacity dye bath. Of course, the inside of the nonwoven fabric is not dyed. In the batch dyeing method using a jet dyeing machine, there is no difference in dye density in the longitudinal direction, but like other methods, it is impossible to dye the inside of the nonwoven fabric.

Therefore, the present invention aims to solve the problems of the conventional dyeing methods as described above.

[Means to solve the problem]

According to the present invention, when dyeing artificial leather made of urethane-impregnated nylon nonwoven fabric or silver-covered artificial leather made by laminating a dyeable urethane skin to urethane-impregnated nylon nonwoven fabric, acid dyes or metal-containing dyes, alcohol, and penetrant dyes can be used. A method for dyeing artificial leather is provided, which is characterized by continuous dyeing by impregnation with a dye bath consisting of a composition of agent and water.

[Effect]

In the present invention, a composition consisting of an acid dye or a 1.2-metal-containing dye, an alcohol, a penetrant and water is used as a dyeing bath. Alcohols significantly increase the rate at which dyes adhere to urethane-impregnated nylon nonwoven fabrics and urethane skins, making continuous dyeing possible for short periods of time at temperatures close to room temperature. In order to improve dye solubility, there is no problem in using an aprotic polar solvent as an additional solvent.Additionally, by adding this kind of solvent, selective adsorption of the dye to the nylon nonwoven fabric side is suppressed, and the surface layer is It also has the advantage of facilitating color density.

The penetrant solves the problem of poor penetration into the interior of the nonwoven fabric when using a mixed system of alcohol and water, and makes it possible to dye the inside of the nonwoven fabric. In other words, in the case of suede-like artificial leather, dyeing can be obtained that penetrates into the interior in a short period of time, and in the case of silver-finished artificial leather, the outer layer and the nonwoven fabric side are simultaneously dyed for a short period of time.
It also makes it possible to uniformly dye the inside of the nonwoven fabric.

Hereinafter, the constituent elements of the present invention will be specifically explained. Urethane-impregnated nylon nonwoven fabric is disclosed in Japanese Patent Application Laid-Open No. 51-1305.
It is manufactured by a known method such as No. 5, and the urethane includes several tens of dyeable urethanes containing basic nitrogen.
As the dyeable urethane skin, which is preferably impregnated within a range of 1.5%, Petalua 20, Betalua 007, etc. manufactured by Toyo Polymer Co., Ltd. can be used. It is best to use a dry laminate-like adhesive to bond this to the urethane-impregnated nylon nonwoven fabric.
It is also possible to form a dyeable urethane skin by gravure technique.

The dye used for dyeing may be an acid dye, but milling type acid dyes or metal-containing dyes are preferred in consideration of fastness. As alcohols that promote dyeing, those having a solubility in water of 50 or more, such as methanol, ethal, propyl alcohol, isopropyl alcohol, and furfuryl alcohol, are preferable, and their proportion in the dye bath is preferably 20 to 100% by weight. The dyeing speed increases as this ratio increases. Further, if the weight is less than 20 weight, there is little advantage in accelerating dyeing.

In order to increase the solubility of dyes, it is permissible to use aprotic polar solvents such as dimethylformamide, dimethylacetamide, dimethyl sulfoxide in an amount not exceeding 50% by weight in the dye bath. The addition has the advantage of suppressing the selective adsorption of dyes to the urethane-impregnated nylon nonwoven fabric and facilitating control of the color density of the skin during continuous dyeing.

As the penetrant to be added to the dye bath, an anionic or nonionic penetrant that does not cause problems such as dye precipitation is selected. The range of usage is not limited, but dye bath drop 0.01
It is desirable that the permeation time is within 10 seconds when cc is dripped from a height of 5cII.When dyeing artificial leather with lI, if the permeability is poor, the part that has permeated into the non-woven fabric may be damaged. Unpenetrated areas occur, which causes dark and light staining spots when viewed from the silver side.

To prepare a dye bath, it is best to dissolve the dye in alcohol or an aprotic polar solvent, and then add water and penetrant in sequence.
In addition, hot water may be used instead of water to facilitate the dissolution of the dye, and the mixture is allowed to stand overnight, and when it reaches room temperature, undissolved dye and virgoo are removed by filtration, and the mixture is used for dyeing. In the dyeing operation, an apparatus having an impregnating bath and a puff goo is used, and the object to be dyed is continuously fed into the dyeing bath, and the puff goo picks up the dye by 50 to 120%. A dyeing bath is added in response to a decrease in the amount of bath, but since the dye concentration in the dyeing bath decreases due to selective absorption, a dye solution with a concentration higher than the concentration at the hull temperature is added.

Dyeing may be completed when the mangle drawing is finished, but
To ensure complete dyeing, a method may be used in which the product is rolled up and left for 5 hours or more and then washed with water.The contact time between the dyed object and the dyeing bath is 30 hours.
Less than a second is sufficient. The ratio of the weight of the dyed object immersed in the dyeing bath to the weight of the dyeing bath, that is, the bath ratio, is preferably 1:100 or less. If the bath ratio is large, excess dye than is actually used for dyeing may be required. Become.

〔Example〕

The present invention will be further explained below with reference to Examples.

Example 1 A dye bath consisting of the following composition was prepared.

Kayaa+ol Mill, Brown 4GH1
% (Nippon Kapowder Co., Ltd. product) Perex OTP 3% (Kao Soap Co., Ltd. product) Methanol 60% Water
A nonwoven fabric made of ultrafine nylon yarn impregnated with 40% by weight of 32% dyeable urethane was used as the dyed material. Dyeing bath 0.01c
The penetration time of c from a height of 5CI was less than 1 second. The object to be dyed was immersed in the dyeing bath for 5 seconds, picked up with a mangle and squeezed to 80%.Then, it was wound up on a metal rod, left at room temperature for 10 hours, washed with water, and then dried.

The dyed object was dyed in a uniform brown color, and the nonwoven fabric was dyed evenly inside.

Example 2 A nylon ultrafine nonwoven fabric impregnated with dyeable urethane in an amount of 40% by weight and having a thickness of 0.8-1 was used as a base material. A film of Petalua 20 (produced by Toyo Polymer Co., Ltd.) was formed as a surface layer on the release paper to a thickness of 8 μm, and a film of Rezamin UD 220 (produced by Seiko Kasei Co., Ltd.) and block isocyanate was formed as an adhesive to a thickness of 10 μm. By bonding these together, dyeable artificial leather was obtained.

Next, the following dyeing bath was prepared.

Kayanol Mill, Green GW
1% (product of Nippon Kapowder Co., Ltd.) Perex OTP 2% (product of Kao Soap Co., Ltd.) Ethanol 70% water
Immerse the 27% dyed item in the dye bath for 5 seconds and pick it up with a mangle at 80%.
The mixture was squeezed, immediately washed with water, and dried.

An artificial leather was obtained in which the urethane skin side was a clear green color and the inside of the nonwoven fabric was uniformly dyed.

Comparative Example 1 In Example 2, the same dyeing bath was used except that no methanol was used, and the same procedure was used to dye the 0 epidermis, which was not dyed at all, and no characteristics of dyeable artificial leather were observed. Ta.

Comparative Example 2 Dyeing was carried out under the same operating conditions as in Example 2 except that Pellex OTP was not used in the dye bath.

The epidermis was dyed green, but due to the penetration of the dye bath into the nonwoven fabric on the back side, dark and light staining occurred.

Example 3 The silver-finished artificial leather prepared in Example 2 was used as a dyed object. In addition, a dyeing bath having the following composition was prepared.

Mitsui Nylon Black GL
4% (Mitsui Toatsu Chemical Co., Ltd. product) Perex OTP 2% (Kao Soap Co., Ltd. product) Methanol 60% Water
After immersing the 54% dyed item in the dyeing bath for 20 seconds, pick it up with a mangle 8
When the dye was squeezed to 0%, wound up on a metal rod, and left at room temperature for 10 hours, and then washed with water, almost no dye came off. The samples were dried at 100°C for 10 minutes.

An artificial leather was obtained in which the outer skin side was dyed deep black, and the nonwoven fabric side was also dyed black uniformly to the inside.

Example 4 A nonwoven fabric made of ultrafine nylon thread impregnated with dyed urethane in an amount of 40% by weight and having a thickness of 1.3 μm was used as a base material. Betalure 20 (produced by Toyo Polymer Co., Ltd.) was applied as a surface layer to the release paper to a thickness of 8 μm, and on top of that, Rezamin UD220 (produced by Seiko Kasei Co., Ltd.) and block isocyanate were applied as adhesives to a thickness of 10 μm. By bonding with the above base material, dyeable artificial leather was obtained.

Next, a dye bath having the following composition was prepared.

Ta1on Fast Red BRL
3% (Bayer product) Perex OTP 2% (Kao Soap Co. product) Isopropyl alcohol 80% water
Immerse the 15% dyed item in the dyeing bath for 10 seconds and pick it up with a mangle at 80
%, immediately washed with water and dried.

An artificial leather was obtained in which the urethane skin side was a vivid deep red color, and the nonwoven fabric side was dyed red all the way to the inside.

Example 5 A 0.8 μm thick nonwoven fabric made of ultrafine nylon thread impregnated with dyeable urethane in an amount of 40% by weight was used. Betalure 20 (produced by Toyo Polymer Co., Ltd.) was applied as a surface layer to the release paper to a thickness of 80 μm, and on top of that, Lethermin UD 220 (produced by Seiko Kasei Co., Ltd.) and block isocyanate were applied as adhesives to a thickness of 10 μm. It was bonded to the above base material.

Next, a dye bath having the following composition was prepared.

Kayakalan Brown GL
3% (Nippon Gunpowder Co., Ltd. product) Perex OTP 2% (Kao Soap Co., Ltd.) Methanol 30% Dimethylformamide 30% Water
The 35% dyed article was immersed in a dye bath for 5 seconds, squeezed to a pick-up of 80% using a mangle, and immediately washed with water and dried.

An artificial leather was obtained in which the urethane skin was dark brown and the nonwoven fabric side was dyed brown to the inside.

Claims (1)

[Claims] 1. When dyeing artificial leather made of urethane-impregnated nylon nonwoven fabric or silver-covered artificial leather made of urethane-impregnated nylon nonwoven fabric with dyeable urethane skin attached, acid dyes, metal-containing dyes, alcohol A dyeing method for artificial leather, characterized by continuous dyeing by impregnation with a dye bath consisting of a penetrant and water. 2. The solubility of alcohol in water is 50 or more,
The proportion of alcohol in the dye bath is 20% by weight or more,
The method according to claim 1. 3. The method according to claim 1, wherein the penetrant is contained in an amount such that the penetration time is 10 seconds or less when a 0.01 cc dye bath drop is dropped from a height of 5 cm. 4. The method of claim 1, wherein the dyeing bath further comprises an aprotic polar solvent in an amount not exceeding 50% by weight.