JP2002275768A - Method for dyeing synthetic polyamide fiber - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for dyeing a synthetic polyamide fibers with an iron mordant. SOLUTION: This method for dyeing the synthetic polyamide fibers is characterized by treating the synthetic polyamide fibers with a dye bath containing a disazo dye in the form of a free acid represented by the general formula (1) [wherein, ring-A may be substituted with Cl, nitro group, or a 1-3C alkyl group; and ring-B may be substituted with Cl, F, or a 1-3C alkyl group] at pH 3-4 and then carrying out iron mordanting with a mordant solution composed of an aqueous solution of an iron salt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for dyeing a synthetic polyamide fiber, and more particularly to a method for dyeing a synthetic polyamide fiber with a specific disazo dye.

[0002]

2. Description of the Related Art Heretofore, in dyeing synthetic polyamide fibers such as nylon, acid dyes or metal complex hydrochloric acid dyes have been mainly used. Acid dyes are inferior in fastness, and metal complex hydrochloric acid dyes contain heavy metals such as chromium and have a problem of high environmental load. On the other hand, studies have been conducted on mordants using metals having lower environmental toxicity, such as nickel, cobalt, and iron. Of these, iron mordant is expected in terms of environmental toxicity. However, this iron mordant is more difficult to obtain particularly fast enough to be practically used than other metal mordants. Not
It has hardly been put to practical use.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide a practical dyeing method for synthetic polyamide fibers, which suppresses a decrease in rub fastness and light fastness due to iron mordant dyeing.

[0004]

In order to achieve the above object, the present invention provides a synthetic polyamide fiber comprising a disazo dye represented by the general formula (1) in the form of a free acid having a pH of 3-4.
And then iron-mordanting with a mordant comprising an aqueous solution of an iron salt.

[0005]

Embedded image

[In the above formula, ring A may be substituted with Cl, a nitro group or an alkyl group having 1 to 3 carbon atoms, and ring B may be substituted with Cl, F or an alkyl group having 1 to 3 carbon atoms. May be. ]

In the present invention, since the dyeing bath is maintained at a pH of 4 or less, the generation of iron hydroxide which causes a decrease in the fastness to friction is suppressed. At the same time, the light fastness is improved. However, when the pH of the dye bath is less than 3, embrittlement may occur due to excessive dyeing of the polyamide fiber. More preferred pH of the dyeing liquor
The range of values is 3.5-3.8.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION A mordant comprising an aqueous solution of an iron salt comprises:
Usually it is within or near the pH of the dye bath. Therefore, although the adjustment of the pH value of the aqueous solution of the iron salt is completely unnecessary, the iron salt may be used by dissolving it in an acidic aqueous solution, preferably an aqueous solution of acetic acid, in order to suppress the generation of iron hydroxide in the solution. . Furthermore, after dyeing is completed, soaping with a soaping agent is performed. The iron mordant method of the present invention can be suitably used for dyeing a fiber material obtained by spinning nylon or a blend of nylon and other fibers.

[0009]

The present invention will be specifically described below with reference to examples. Each fastness test and measurement were performed by the following methods. Friction fastness: JIS L0849-1996 Gakushin method (measured in gray scale) Light fastness: JIS L0842-1996
Example 1 (measured in blue scale)

[0010]

Embedded image

A dye having the structure of the above (2) in the form of a free acid is added to nylon 66 at 4% o. w. f. And 1% o. w. f. PH of the dyeing bath with acetic acid
The temperature is adjusted to 3.5, and the temperature is raised from the initial bath 40 ° C to 98 ° C over 1 hour while stirring the dyeing bath at a bath ratio of 30: 1. 98
After maintaining at 30 ° C. for 30 minutes, 1% ferrous sulfate dissolved in 1% aqueous acetic acid solution was added. w. f. Added. After maintaining for a further 60 minutes, the material to be dyed is taken out of the dyeing bath and the soaping agent 2%
o. w. f. Into a washing bath having a bath ratio of 30: 1, the temperature is raised from room temperature to 80 ° C., and maintained for 20 minutes. Thereafter, it was washed with water, and the dyed product taken out was dried. The dyed product thus obtained was dyed dark black and had good fastness to rubbing and light. Table 1 shows the results.

Comparative Example 1 The dye used in Example 1 was adjusted to a dye bath pH of 5.5, and dyed and soaped under the same conditions as in Example 1 except that ferrous sulfate dissolved in water was used. Table 1 shows the fastness results of the dyeings thus obtained.

[0013]

[Table 1]

[0014]

According to the present invention, iron mordant dyeing of synthetic polyamide fiber and the like having excellent friction fastness and light fastness can be achieved, and high fastness can be obtained without using heavy metals such as chromium. It is useful for dyeing nylon with color.

Claims (3)

[Claims] A synthetic polyamide fiber is prepared by adding a disazo dye represented by the general formula (1) in the form of a free acid to a pH of 3-4.
A method for dyeing a synthetic polyamide fiber, comprising: treating with a dye bath, followed by iron mordant with a mordant comprising an aqueous solution of an iron salt. Embedded image [In the above formula, ring A is Cl, a nitro group or a carbon number of 1 to 3.
And ring B may be Cl, F
Alternatively, it may be substituted with an alkyl group having 1 to 3 carbon atoms. ] 2. The ring A in the general formula (1) of the disazo dye
Is an unsubstituted ring, wherein ring B is Cl at position 3.
The method for dyeing a synthetic polyamide fiber according to claim 2, wherein the ring is a ring substituted with: 3. An iron salt aqueous solution obtained by dissolving ferrous sulfate in an acetic acid aqueous solution.
3. The method for dyeing a synthetic polyamide fiber according to item 1.