JPS597826B2 - How to bleach textiles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the low temperature bleaching of textiles with chlorite.

Generally, when bleaching fibers with chlorite, various acids are added to an aqueous chlorite solution, the pH is adjusted to 3 to 4, and the bleaching is carried out at 90° C. or higher for a certain period of time by heating with steam.

In recent years, in the textile processing industry, due to the soaring prices of heavy oil, etc., there has been an active movement towards resource and labor saving.

Bleaching at a high temperature of 90° C. or higher requires a huge amount of steam, and the cost required for heating is also considerable.

Additionally, the work environment is extremely poor as the plant operates under high temperature and humidity.

For the reasons mentioned above, there is a strong desire to develop a bleaching method at low temperatures.

In the method of activating chlorite by adding various acids, 9
A temperature of 0° C. or higher is required, and lower temperatures significantly reduce the bleaching effect.

In addition, as other methods for activating chlorite, ester activation method and hypochlorous acid activation method are known; Even if the bleaching temperature is 93-96°C, this method requires a longer time compared to the acid activation method, and although the hypochlorous acid activation method can be used for bleaching at low temperatures, it is not suitable for acid activation in terms of whiteness and strength. Inferior to activation method.

The present inventors have repeatedly conducted research and development on a low-temperature bleaching method that provides whiteness equivalent to that of the acid activation method, and have established the low-temperature bleaching method of the present invention.

That is, the present invention provides a method for bleaching textiles, which comprises treating textiles with an aqueous solution containing chlorite and a polysaccharide derivative obtained by reacting a polysaccharide with periodic acid or a salt thereof. be.

The chlorites used in the method of the present invention include alkali metal salts such as sodium chlorite and potassium chlorite.

The polysaccharide derivatives used in the method of the present invention can be easily obtained by dispersing polysaccharides such as starch cellulose or vegetable gum in water, adding periodic acid or its salt, stirring, and then separating the solid portion. .

The polysaccharide derivative obtained by the above reaction is an odorless white crystal, and judging from the fact that its infrared absorption spectrum has a large absorption peak of 10H at 3460°, it is thought to consist of bonding units represented by the following formula. It will be done.

In addition, if you want to obtain this aqueous solution, add 4
It can be easily obtained by dissolving it in hot water heated to 0°C to 90°C and adjusted to pH 1 to 6.

The amount of polysaccharide derivative added in the method of the present invention is 0.01 to 2 parts by weight, preferably 0.1 to 1 part by weight, per 1 part by weight of chlorite.

If the amount of the saccharide derivative added is less than 0.01 part by weight, the effect of the saccharide derivative will not be fully exhibited, and if it exceeds 2 parts by weight, it will be economically disadvantageous.

``To carry out the method of the present invention, first a predetermined amount of a polysaccharide derivative is added to a solution A of chlorite.

To further improve the bleaching effect, known surfactants or mineral acids or organic acids may be added, and known salt dioxide gas suppressants may be added to prevent the generation of chlorine dioxide gas. You can.

By using the method of the present invention, the birch fibers are immersed in the bleaching solution prepared in this way, or the fibers are impregnated with the bleaching solution and bleached at room temperature to 70°C.
Whiteness equivalent to or higher than that obtained by acid activation method carried out at temperatures above 70°C can be obtained by setting the bleaching temperature to 70°C.
We were able to significantly reduce the amount of steam used.

Furthermore, the acid perspiration method has a bleaching effect depending on the pH of the bleaching solution2, so careful consideration must be given to adjusting the pH.
In the method of the present invention, since the bleaching effect does not depend too much on the pH of the bleaching solution, the work can be simplified.

Furthermore, in the method of the present invention, bleaching power can be achieved at a pH around neutrality, and since the bleaching temperature can be lowered, embrittlement of the fibers does not occur, and the texture and strength are improved.

Hereinafter, embodiments of the method of the present invention will be explained with reference to Examples.

The whiteness in the following examples and comparative examples is JISP812
Hunter Whiteness is defined as 3.

Examples 1-4 Sodium chlorite 1.5g/t1 score roll 95 (
To a slurry in which 2.0 g/t of surfactant manufactured by Kao Atlas ■ and 162 g of potato starch were dispersed in 3 tons of water, 214 g of sodium periodate was added and stirred at room temperature for 2 hours. 800rI bleaching solution containing sugar derivatives adjusted to each concentration shown in Table 1
80 g of cotton knitted cloth (whiteness: 59.4%) was immersed in the solution and bleached at 60° C. for 90 minutes.

The results are shown in Table 1. Comparative Examples 1 to 2 For comparison with the acid activation method, Examples 1 to 4 were followed except that formic acid, which is commonly used in the acid activation method, was used instead of the polysaccharide derivative.

The results are shown in Table 1.

Comparative Example 3 Comparative Examples 1 and 2 were followed except that the concentration of sodium chlorite was 3.0 g/l.

The results are shown in Table 1.

Comparative example 4 Comparative Examples 1 and 2 were followed except that the bleaching temperature was 95°C.

The results are shown in Table 1. As is clear from Table 1, in the acid activation method, only 78.8% whiteness can be obtained at a bleaching temperature of 60° C. when sodium chlorite is 1.59/t.

On the other hand, according to the method of the present invention, a whiteness of 82 coefficients or more can be obtained at a bleaching temperature of 60°C, which is equivalent to the whiteness obtained by the acid activation method at 95°C.

Furthermore, in the acid activation method, even if the amount of sodium chlorite used is doubled, the bleaching effect is inferior to that of the method of the present invention.

Example 5 Sodium chlorite 1. 5 9/l, 1 Score Roll 95 (surfactant manufactured by Kao Atlas ■) 2.0 g/
75 g of a bleaching solution consisting of 6 g/l of a polysaccharide derivative obtained by adding 214 g of sodium periodate to a slurry in which 162 g of corn starch and 162 g of corn starch were dispersed in 3 tons of water, stirring at room temperature for 2 hours, and separating the resulting slurry. 15 g of cotton stockinette was impregnated with the solution and bleached at 20°C for 17 hours.

As a result, the decomposition rate of sodium chlorite was 85%.
The whiteness was 82.2%.

It can be seen that it has sufficient bleaching effect even at a low temperature of 20°C.

Claims (1)

[Claims] 1. A method for bleaching fibers, which comprises treating fibers with an aqueous solution containing chlorite and a polysaccharide derivative obtained by reacting a polysaccharide with periodic acid or a salt thereof.