JPH0565627B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for dyeing artificial leather. More specifically, we are creating a uniform and strong artificial leather that has air permeability and moisture permeability, which is made of a tangled body of ultra-fine to ultra-fine fibers made of polyamide and porous polyurethane, without impairing its characteristics such as napping and texture. Concerning how to dye.

(Prior art) Artificial leather made of ultrafine polyamide fibers and porous polyurethane has a very soft surface feel, a suede-like and elegant appearance, and is similar to natural leather in terms of breathability and moisture permeability. Many of them outperform natural products in various aspects, such as being resistant to wrinkling, being able to be made into long lengths, having excellent sewing yields and dimensional stability, being available in a wide variety of colors, and having high color fastness. As a result, research and development of manufacturing technology and processing methods have progressed, and it has come to be widely used in the apparel field.

Especially with the recent penetration of leather fashion,
There is a strong desire to increase added value through a more luxurious appearance and to differentiate products, and there is a demand for higher quality and diversification of color tones while still taking advantage of the characteristics of the materials.

Traditionally, artificial leather has been colored using different methods depending on the material, fineness, composition ratio, etc., but pigments have been used together with polymeric resins and solvents to color them using the pad method, gravure printing method, etc. Alternatively, dyes such as disperse dyes, oil-soluble dyes, acid dyes, etc. are used alone or in combination with polymeric resins and solvents for dyeing using the pad method, textile printing method, gravure printing method, etc.

(Problems to be Solved by the Invention) However, when artificial leather is colored with pigments by the pad method, gravure printing method, etc., although it is effective in improving the surface abrasion resistance and bending resistance, it damages the fibers. Swelling or crowding between fibers impairs texture, air permeability, and moisture permeability. Furthermore, the same problems as mentioned above occur when dyeing with various dyes by a textile printing method, a gravure printing method, or the like. Alternatively, when dyeing is carried out using various dyes using the dip dyeing method that is commonly used for dyeing polyamide fibers, the dyeing is carried out at a relatively high temperature, for example, 90
~110°C, and in JP-A No. 59-112085, it is sometimes carried out at 70°C or higher, and regardless of the presence or absence of a solvent, uneven dyeing of polyamide napped fibers and polyurethane base fabric, and surface napped irritation are observed. In addition, pilling and fraying of the hair tend to occur, which tends to impair the texture.

Such problems are more likely to occur in so-called bag-like artificial leather, in which polyamide fibers are ultra-fine fibers, especially when several types of dyes are mixed to create a blended color.
It has disadvantages such as uneven dyeing and a decrease in fastness, and a method to solve these problems is strongly desired.

The purpose of the present invention is to dye artificial leather made of porous polyurethane with polyamide-based ultrafine or ultrafine fibers without impairing its texture or other material properties, and to achieve uniform dyeing without unevenness or irritation, resulting in excellent quality. An object of the present invention is to provide an industrially advantageous method for obtaining dyed products having dyeing properties such as fastness.

(Means for Solving the Problems) In order to solve the above-mentioned drawbacks in coloring artificial leather, the present inventors investigated the coloring process in detail and found that dyes containing metal complex dyes or acid dyes The present invention has been completed by discovering that each of the above-mentioned problems can be solved by dyeing artificial leather under specific conditions using a bath.

That is, the present invention is a method for dyeing artificial leather, which comprises dyeing artificial leather made of polyamide fibers and porous polyurethane using a dye bath containing a metal complex dye or an acid dye at a temperature of 50°C or lower. be.

The dyeing method of the present invention is useful for dyeing any known artificial leather made of ultra-fine to ultra-fine polyamide fibers with a monofilament fineness of about 0.5 denier or less and porous polyurethane. Artificial leather with ultra-fine polyamide fibers is effective.

The polyamide fiber in the present invention is obtained by a known method, such as a composite spinning method or a mixed spinning method, or a combination of these spinning methods to obtain a multicomponent fiber whose fiber cross section has a sea-island structure. Then, at any stage of manufacturing artificial leather, there is a method of extracting or decomposing and removing the sea components constituting this multicomponent fiber, or a method of manufacturing artificial leather using split fibers obtained by a composite spinning method. A method of dividing the fiber between polymers by chemical or mechanical treatment at the stage of step 2, a method of directly obtaining ultrafine fibers by a flash spinning method, a super draw method, a normal spinning method, etc., and an alkali reduction method, etc. It can be obtained by various methods such as ultra-fine method.

Porous polyurethanes include polyester polyol type polyurethanes, polyether polyol type polyurethanes, and mixtures thereof. Methods for fixing porous polyurethane to polyamide fibers include a wet color coagulation method and a dry coagulation method, but the wet coagulation method is preferable when a raised fluff with excellent flexibility is desired.

The metal complex dyes used in the method of the present invention include complex-forming azo dyes having o,o'-dihydroxyazo, o-hydroxy-o'-carboxyazo, or o-hydroxy-o'-aminoazo structures, and cobalt-forming azo dyes. Examples include soluble dyes formed by forming complex salts with metal ions such as chromium, nickel, iron, etc. in a ratio of 1:1 or 2:1, and in particular dyes containing one or more alkyl-substituted or unsubstituted sulfamoyl groups as the soluble group. have In addition, the azo dye before complexing may be mono-, di- or triazo,
The aromatic nucleus may be substituted with, for example, a nitro group, a halogen, a lower alkyl group, a sulfonic acid group, or the like. The two moles of azo dye in the 2:1 case may be the same or different. However, when the complex dye contains a sulfonic acid group, it is preferable that there is one sulfonic acid group in one molecule of the dye, and artificial leather colored with a complex dye having two or more sulfonic acid groups may have problems particularly in water resistance. easy.

Specific examples of dyes belonging to these types include, for example, 1:1 type dyes with trade names such as Sumilan dye (Sumitomo Chemical Co., Ltd.), Palatin Fast dye (BASF Co., Ltd.), and Neolan dye (Neolan dye). Ciba Geigy products), 2:1 types include product names, Lanyl dyes (Sumitomo Chemical products), Kayakalan dyes (Nippon Kayaku products), Lrgalan dyes (Ciba Geigy products), etc. can be used alone or in combination.

Examples of the acid dye used in the present invention include leveling type acid dyes, half-milling type acid dyes, milling type acid dyes, etc. Milling type acid dyes are preferable, and specifically, the trade name Suminol Leveling Dye, Suminol milling dye (all manufactured by Sumitomo Chemical), Kayanol dye, Kayanol milling dye (all manufactured by Nippon Kayaku), Techilon dye, Elionyl dye (all manufactured by Ciba Geigy),
Examples include Nyrosan E and Nyrosan N (all of which are manufactured by Sandoz), which can be used alone or in combination.

Among the dyes mentioned above in the present invention, metal complex dyes, particularly 2:1 type metal complex dyes, are preferably used.

The dyeing process of the present invention is carried out at a temperature of 50°C or lower. If the dyeing process is carried out at a temperature of less than 10℃, it will require a long time for dyeing, which is industrially undesirable.On the other hand, if the temperature exceeds 50℃, the polyamide ultrafine or ultrafine fibers will be susceptible to physical changes. The difference in dyeing speed in compound dyeing using the above dyes is
This causes uneven dyeing, surface irritation, clumping, fraying of the raised pile, etc., resulting in a decrease in texture and fastness. Therefore, the dyeing treatment of the present invention is carried out at a temperature below 50°C, preferably
The reaction is carried out at a temperature of 10°C or higher, but from an industrial standpoint, it is more preferably carried out at room temperature (usually about 20 to 30°C).

The method of dyeing treatment is not particularly limited, but the artificial leather may be immersed in a dye bath and exhaust dyeing may be performed, or the artificial leather may be continuously immersed in a dye bath,
If necessary, dyeing can be carried out by squeezing at an appropriate squeezing rate and maintaining a predetermined temperature after winding up. The immersion time in the dyebath is determined appropriately depending on the temperature and method of the dyeing process, but in the case of exhaust dyeing by immersion, it is relatively long, from several tens of minutes to 20 hours, and in the case of a continuous method, it is relatively long. It is as short as several seconds to several minutes. After dyeing, the desired dyed product can be obtained by washing with water and drying. However, after dyeing, if necessary, the fastness of the dyed product can be improved by performing preliminary drying and then steaming treatment. This steaming process typically takes about
This is done using steam at 100°C for about 5 minutes, but if the steaming time is too long, the surface of the fibers will be damaged, causing not only a loss of texture but also irritation.

The amount of dye used is not particularly limited and is appropriately determined depending on the type of dye, dyeing method, etc., but usually when exhaust dyeing is performed by immersion, the bath ratio is 1:30 to 1:30. 100 is 0.1-10% owf,
In the case of continuous method, it is 100g/or less.

To make a dye bath, a predetermined amount of dye is sufficiently dissolved in an appropriate amount of water at room temperature or elevated temperature, adjusted to neutral or slightly acidic, dyeing aids are added if necessary, and then a predetermined amount of water is added. can be adjusted. Examples of dyeing aids used to improve the solubility, permeability, and leveling properties of dyes include dioxane, cellosolve, carbitol, butanol, dimethyl sulfoxide, dimethylformamide, and diacetone alcohol. However, when the amount of these dyeing aids used increases, problems such as a decrease in the fastness of dyed products occur.

(Functions and Effects) According to the artificial leather dyeing method of the present invention, there is no uneven dyeing between polyamide fibers and polyurethane base fabric, no unevenness on the raised surface, and it is possible to dye not only light colors but also medium to deep colors. It is also possible to obtain uniform dyeing, and there is almost no wear and tear on the nape or occurrence of pilling. In addition, uneven dyeing caused by blended dyes is eliminated, and as a result, good light fastness and wettability of metal complex dyes and acid dyes can be sufficiently maintained. Furthermore, the dry cleaning properties of dyed products are improved compared to when disperse dyes or oil-soluble dyes are used.

In addition, the dyeing method of the present invention can significantly reduce fuel consumption because the dyeing process is carried out at a relatively low temperature.

(Example) The present invention will be specifically described below with reference to Examples, but the present invention is not limited thereto. In the examples, parts and % indicate parts by weight and % by weight.

Example 1 A mixed spun fiber (3 denier) consisting of 50 parts of polyamide and 50 parts of polyethylene was crimped and cut (51 mm).
A cross-wrapped web was prepared, and sufficient needle punching was performed to obtain a three-dimensionally entangled nonwoven fabric. This nonwoven fabric was contained in a 12% dimethylformamide solution of polyester polyurethane elastomer, squeezed, wet-coagulated in an aqueous solution, thoroughly washed with warm water, and dried to obtain a sheet-like product. This sheet-like material is immersed in perkleen to extract and remove the sea component polyethylene in the fibers, dried, and then buffed to fluff the surface and have a monofilament fineness of 0.004.
We obtained a denier bag-like artificial leather fabric.

This gray fabric was moistened in warm water at 45-50℃ for several minutes, dehydrated, and then placed in the following dye bath maintained at a temperature of 20℃ in a shaking dyeing machine, shaken at 20℃ overnight, and the next morning. The dyed material was taken out, washed with water, and dried to obtain brown artificial leather.

(Dye bath) Dye: Lanyl Byown R (ClAcid Byown 28,
2:1 type chromium complex dye, Sumitomo Chemical Co., Ltd.) Bath ratio: 1/60 Concentration: 2% owf The obtained artificial leather has a surface L value of 48.4 and a back surface of
48.1, and there was no difference in light fastness or washing fastness between the front and back sides. There was also no surface irritation, and no pilling, fraying, etc. were observed.

Example 2 The same procedure as in Example 1 was carried out except that the dye bath treatment temperature was 30 to 35°C and the treatment time was 120 minutes. Obtained leather.

Example 3 The same artificial leather gray fabric prepared in Example 1 was
Wet it in warm water at 45-50℃ for several minutes, dehydrate it, then put it into the following dye bath maintained at 40-45℃ in a shaking dyeing machine, shake it at a temperature of 40-45℃ for 1 hour, and take it out. The material was washed with water and dried to obtain brown artificial leather.

(Dye bath) Dye: Lanyl Byown GR (ClAcid Byown 19,
2:1 type chromium complex dye, Sumitomo Chemical Co., Ltd.) Bath ratio: 1/60 Concentration: 2% owf The obtained artificial leather has no uneven dyeing on both the front and back sides.
It had a beautiful texture with no surface irritation, pilling, or fraying. It also has excellent light fastness and washing fastness.

Example 4 The same artificial leather gray fabric prepared in Example 1 was
After moistening for a few minutes in 45-50℃ warm water and dehydrating, 25
Lanyl Byown GR (C.
l.Acid Byown 19, 2:1 type chromium complex dye,
Sumitomo Chemical Co., Ltd. product)) was padded in a dye bath containing 10g/g of the product, rolled up, left at room temperature for 20 hours, washed with water,
Artificial leather was dried and uniformly dyed brown. No surface irritation was observed, and the dye fastness also showed good results.

Example 5 The same artificial leather gray fabric prepared in Example 1 was
After dehydration by moistening in warm water at 30-35℃ for several minutes, it is placed in a dye bath consisting of the following mixed dye kept at 3.0-35℃ in a shaking dyeing machine, and shaken at a temperature of 30-35℃ for 1 hour. After treatment, it was taken out, washed with water, and dried to obtain reddish-blue artificial leather.

(Dye bath) Dye: ClAcid Blue 167 85 parts ClAcid Blue 171 14 parts ClAcid Violet 75 1 part (Both are 2:1 type metal-containing dyes) Concentration: 2% owf Bath ratio: 1/60 The obtained artificial leather is It was dyed reddish-blue uniformly, with no surface irritation, no pilling, and no fraying.

In this example, the artificial leather after the shaking treatment was taken out, dehydrated by a mangle, and then steamed for 5 minutes.
When washed with water and dried, the washing fastness with respect to nylon staining was about half a grade better than the above example.

Example 6 The same artificial leather raw machine as prepared in Example 1 was
After moistening in warm water at 50℃ for several minutes and dehydrating, it is placed in the following dye bath maintained at 35 to 40℃ in a shaking dyeing machine, and after processing for 90 minutes at a temperature of 35 to 40℃, the dyed item is It was taken out, washed with water, and dried to obtain green artificial leather.

(Dye bath) Dye: Suminol Milling Brilliant Green 5G (C.
l.Acid Green 28, Sumitomo Chemical Co., Ltd.) Bath ratio: 1/50 Concentration: 3% owf Auxiliary agent: ammonium sulfate, 3% owf The obtained artificial leather had no difference between the front and back sides, and no surface irritation was observed. Moreover, the light fastness was also good.

Comparative Example 1 In Example 1, the artificial leather gray material was immersed in a dye bath at 30°C, then heated to 90°C at a rate of 1°C/min, shaken and dyed at 90°C for 1 hour, taken out, and washed with water. , and dried to obtain brown colored artificial leather.

The L value was 55 on the front side and 57.3 on the back side, which was a little lighter than in Example 1 and uneven, and surface irritation was observed. The fastness was almost the same as in Example 1, but pilling and fraying occurred on the surface.

Comparative Example 2 In Example 4, after putting the artificial leather into the dye bath,
Raise the temperature to 90℃ at a rate of 1℃/min, and at the same temperature
A reddish-blue colored artificial leather was obtained by shaking for a period of time, washing with water, and drying, but uneven dyeing, surface irritation, pilling, and fraying were observed.

In addition, in terms of washing fastness, discoloration and staining of the base fabric were half a grade lower than those of Example 5.

Claims (1)

[Claims] 1. A method for dyeing artificial leather, which comprises dyeing artificial leather made of polyamide fibers and porous polyurethane at a temperature of 50° C. or lower using a dye bath containing a metal complex dye or an acid dye.