JPS5858460B2 - Bleaching of textile materials with hydrogen peroxide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for preventing deterioration in fiber strength due to bleaching when textile materials are bleached with hydrogen peroxide.

Due to the nature of hydrogen peroxide, bleaching with hydrogen peroxide generally
It is essential to carry out the process in alkaline conditions, and the reason for this is, as described in literature and magazines, that hydrogen peroxide reacts with OH- in alkaline conditions, generating HO□- (H20
2+OH--HO2-+H20) The HO2- is largely involved in bleaching and is said to be effective in bleaching, and normally all fibers have been bleached with hydrogen peroxide in alkaline conditions.

However, the present inventors broke away from the conventional concept of alkaline hydrogen peroxide bleaching and developed a new hydrogen peroxide bleaching method that improved the drawbacks of alkaline hydrogen peroxide bleaching (Japanese Patent Application No. 54-8068 ).

That is, this is a hydrogen peroxide bleaching method characterized by performing weakly acidic hydrogen peroxide bleaching, then adding an alkaline agent, and using the remaining hydrogen peroxide to perform alkaline hydrogen peroxide bleaching.

As a result of further research, the present inventors found that when carrying out weakly acidic hydrogen peroxide bleaching at pH 5 to 7, then adding an alkaline agent, and carrying out alkaline hydrogen peroxide bleaching using the remaining hydrogen peroxide. The present inventors have discovered that the presence of water-soluble salts of aminocarboxylate organic chelating agents in a hydrogen oxide bleaching bath allows for more effective bleaching in the following respects.

■ The presence of water-soluble salts of aminocarboxylate organic chelating agents greatly stabilizes hydrogen peroxide during weakly acidic hydrogen peroxide bleaching, without reducing whitening during weakly acidic hydrogen peroxide bleaching. , the amount of hydrogen peroxide remaining at the end of weakly acidic hydrogen peroxide bleaching increases, allowing continued alkaline hydrogen peroxide bleaching to be carried out at a high concentration, resulting in higher whiteness of textile products.

■ In the case of cotton fabrics, etc., a desizing process is carried out to remove the size prior to hydrogen peroxide bleaching, but depending on the conditions of the bleaching factory, hydrogen peroxide may be Bleaching is sometimes carried out, and in that case, if weakly acidic hydrogen peroxide bleaching is carried out using the method described in Japanese Patent Application No. 8068/1984 with incomplete desizing, the hydrogen peroxide will decompose significantly and the strength of the fiber will deteriorate. There was a drawback.

However, the presence of water-soluble salts of aminocarboxylate organic chelating agents significantly suppresses the decomposition of hydrogen peroxide during weakly acidic hydrogen peroxide bleaching, allowing bleaching to be carried out without deterioration of fiber strength.

■ When bleaching Japanese bleached products, etc., depending on the situation at the bleaching factory,
Long hours (10 to 20 hours) using idle time at night
Weakly acidic hydrogen peroxide bleaching may be used, in which case
The method disclosed in Japanese Patent Application No. 54-8068 had the disadvantage that the strength of the fibers deteriorated if the weakly acidic hydrogen peroxide bleaching was applied for a long time.

However, the presence of water-soluble salts of aminocarboxylate-based organic chelating agents prevents deterioration of fiber strength due to long-term weakly acidic hydrogen peroxide bleaching, and bleaching can be performed using idle time at night.

■ In general, when textile materials contaminated with heavy metals such as iron and copper, which cause hydrogen peroxide to decompose significantly, are bleached with hydrogen peroxide, the hydrogen peroxide decomposes significantly in the areas contaminated with the heavy metals.
It is known that fiber strength deteriorates.

In this case, Japanese Patent Application No. 548068 also had the disadvantage that the strength of the fibers deteriorated due to heavy metal contamination.

However, the presence of water-soluble salts of aminocarboxylate organic chelating agents can significantly prevent strength deterioration due to heavy metal contamination.

The present invention involves the presence of water-soluble salts of aminocarboxylate organic chelating agents in a hydrogen peroxide bleaching bath, and
Weakly acidic hydrogen peroxide bleaching is carried out in one area of 7, then an alkaline agent is added to the system to bring the pH to 8.5-11, and subsequent alkaline hydrogen peroxide bleaching is carried out in the same system using the remaining hydrogen peroxide. This is a method of bleaching textile materials using hydrogen peroxide.

The fibrous materials applied to the method of the present invention are natural, synthetic or semi-synthetic fibers, blends, blends, knits and other textile products of these fibers.

In the method of the present invention, weakly acidic hydrogen peroxide bleaching is carried out at a pH of 5.
It will be held at ~7.

To adjust the n value, for example, when using a neutral surfactant as a bleaching aid (most surfactants generally used in textile bleaching are neutral types), special acid or alkali There is no need to make any adjustments, and the pH falls within the range of 5 to 7 depending on the mixture of water, hydrogen peroxide, and surfactant.

If necessary, adjust the pH to between 5 and 7 using a common acid or alkali.

Bleaching is carried out at a pH of 5 to 7, but as bleaching progresses, the pH of the solution decreases.

If the pH is lower than 5, add alkali to
Adjust H to 5 or higher.

In addition, the amount of hydrogen peroxide is within the range normally used for bleaching and is not particularly limited, but the practical range is 3.
It is appropriate to add 5 to 30 cc/4 of 5φ hydrogen peroxide.

In the alkaline bleaching of the present invention, after the above-mentioned weak acid bleaching, an alkaline agent is subsequently added to the same system to adjust the pH, and residual hydrogen peroxide is used to perform the alkaline bleaching at a weak alkaline pH of 8.5 to 11.

Bleaching is possible even at a pH of 11 or higher, but it is not preferable to raise the pH when the concentration of hydrogen peroxide in the solution is high.

As the additive alkali agent, commonly used alkali agents may be used, such as alkali metal phosphates such as tribasic sodium phosphate and sodium pyrophosphate, sodium metaborate,
Examples include weak acid salts of alkali metals such as soda carbonate and sodium silicate, hydroxides of alkali metals such as caustic soda and caustic potash, alkaline ammonium salts such as aqueous ammonia and ammonium carbonate, and mixtures of two or more of these compounds.

The amount added should be such that the pH is 8.5 to 11.

Examples of the water-soluble salts of the aminocarboxylate organic chelating agent used in the present invention include nitrilotriacetic acid (
NTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), cyclohexanediaminetetraacetic acid (CyDTA), etc., such as N
Examples include a-salt, K-salt, etc.

These are 0.01 to 50% in the hydrogen peroxide bleach bath. /l,
It is preferably used at a ratio of 0.05 to 11'/l.

The method of adding an organic chelating agent is generally the first bath,
In other words, it is added to the bath during weakly acidic hydrogen peroxide bleaching,
Not only can it be added from the initial bath, but it can also be divided and added at appropriate times during the hydrogen peroxide bleaching process depending on the situation, and in some cases, divisional addition may be preferable.

The temperature and time of weak acid bleaching and alkaline bleaching are within the usual range and are not particularly limited, but usually a temperature of 50-12
A temperature of 0° C. and a time of 0.5 to 5 hours is suitable, and the selection is made depending on the type and form of the fiber to be bleached, the type of bleaching equipment, the requirements of the desired product, and the condition of the product.

When high temperature treatment is performed in the alkaline bleaching of the present invention, it is inevitable that the texture will be hard to some extent, so for example, if a soft texture is mainly required, the treatment is carried out at a low temperature.

If high whiteness is desired at the expense of some soft texture, alkaline bleaching is carried out at a high temperature.

In addition, in the method of the present invention, if the remaining amount of hydrogen peroxide is small after weakly acidic hydrogen peroxide bleaching, in order to obtain high whiteness, the insufficient amount of hydrogen peroxide may be added at the same time as the agent A'My'). , alkaline hydrogen peroxide bleaching can also be carried out.

The method of the present invention can be applied to any type of bleaching equipment, such as natural circulation type equipment and forced circulation type equipment, as long as it is not corrosive due to hydrogen peroxide, which is commonly used for bleaching.

In addition, in order to improve the penetration of chemicals into the fibers, a surfactant that is normally used in conventional fiber bleaching is used.

The amount to be used varies depending on the purity concentration and penetrating power of each commercial product, but it should be used according to the application amount of each commercial product.

Generally, a suitable amount is 0.1 to 21/l as a pure content.

According to the present invention, it is possible to perform bleaching with a good texture similar to that of the previous application, high whiteness, no uneven bleaching, and a small amount of staining, and a reduction in process, time, and utility costs compared to the current bleaching method. Environmentally, the quality of bleached products can be significantly improved.

In particular, according to the present invention, the stability of hydrogen peroxide during weakly acidic hydrogen peroxide bleaching is significantly improved, and no matter what conditions the fiber material is exposed to, high-quality bleached products can be produced with less deterioration in fiber strength. can be obtained.

This will be explained in more detail in Examples below.

Note that the seat strength and strength are based on the following measurement method.

(1) Self-produced by Nippon Denshoku Kogyo Kiki, L-a-b using color studio
Measure using the system.

L, a, b indicate the following meanings, L: lightness, a: (-1-1 reddish, (to) greenish, b: (→
Yellow, ←) Blue. Among these, the b value matches well with visual perception, so I judged my seat based on the b value.

The smaller the b value, the lower the yellowness, that is, the higher the whiteness.

(2) Strength The tensile strength was measured using a Toyo Baldwin X-ray and Tensilon, and the strength of the untreated fiber was set at 100. The strength retention rate was determined.

Example 1 Using a Wince bleaching machine, cotton knitted fabric was bleached under the following bleaching conditions.

The results are shown in the table. Weakly acidic hydrogen peroxide bleach additive 35% H2O22oCc7t Sandjin N
IT 14/7 (Sandoz Surfactant) ■EDTA・4Na None ■EDTA・4Na O,2? /l pH 6.0 Bath ratio 1:20 Temperature 1 hour 90°C for 90 minutes Weakly alkaline hydrogen peroxide bleaching agent No. 3 silica soda 31/lN a2
CO36? / t pH 10.1 Temperature 1 hour 90°C for 60 minutes Example 2 Cotton gauze that had not been completely desized was bleached in an Obermeyer bleaching machine under the following conditions.

The results are shown in the table.

Weakly acidic hydrogen peroxide bleach additive 35%H2O23ocC/l Sandjin N
IT 1g/l ■NTAiNa None ■NTA ・3Na O,5? /l pH 6,9 Bath ratio 1:6 Temperature 1 hour 100°C - 60 minutes Weakly alkaline hydrogen peroxide bleach Additive No. 3 silica 52/1 NaOH Appropriate amount pH 10,8 Temperature 1 hour 95°C - 60 minutes Example 3 Natural circulation type The desized Japanese bleached cotton cloth was bleached in a bleaching machine under the following conditions.

The results are shown in the table.

Weakly acidic hydrogen peroxide bleach additive 35% H2O2 15cb/l Sandjin N
IT IS'/A ■DTPA-5Na None Additive Drug ■DTPA ・5Na O,1? /1
pH 6,5 Bath ratio 1:4 Temperature 1 hour 90°C - 15 hours Weakly alkaline hydrogen peroxide bleach Additive No. 3 silica 51/1 NaOH Appropriate amount pH 10,5 Temperature 1 hour 90°C - 3 hours Example 4 With iron and copper A portion of the contaminated 100% cotton broadcloth was mixed into a 100φ cotton broadcloth of the same type that had not been contaminated with iron or copper, and after desizing, bleaching was carried out under the following conditions.

The results are shown in the table. In addition, the white discoloration in the table is the result of measuring the white discoloration of the part not contaminated with iron and copper, and the tensile strength retention in the table is the result of measuring the part contaminated with iron and copper.

Weakly acidic hydrogen peroxide bleach Added drug 35% H2O21ocC/l.

Sandozin NIT 1g/7 ■Additive drug without Cy-DTA/4Na ■Cy-DTA/4Na 3.0?
/ 1 pH 5,5 Bath ratio 1:10 Temperature 1 hour 95℃ - 60 minutes Slightly alkaline hydrogen peroxide bleach Additive No. 3 silica 3 g / 1 NaOH appropriate amount pH 11,0 Humidity 1 hour 95℃ - 60 minutes Iron and copper The contaminated cloth was prepared as follows:
After uniformly impregnating 0.2 yd of an aqueous solution of 0.18 mol of iron into a strip of width 0.5 crrL in the weft direction of the cloth and thoroughly washing it, it was left in an ammonia stream for 30 minutes, and then washed with hot water.
After dehydrating and air drying this, cupric sulfate 0.018 mol/1O3
2- Impregnate the iron stain and allow it to penetrate sufficiently.

Next, it is immersed in a hot solution containing caustic soda and a reducing agent, thoroughly washed with water, and air-dried.

Although iron and copper are insolubilized by this operation, the cloth does not deteriorate due to this operation.

Claims (1)

[Claims] 1. Water-soluble salts of aminocarboxylate-based organic chelating agents are present in a hydrogen peroxide bleaching bath, and weakly acidic hydrogen peroxide bleaching is performed in the pH range of 5 to 7, and then an alkaline agent is added to the system. 1. A method for bleaching textile materials with hydrogen peroxide, which comprises adding hydrogen peroxide to pH 8.5 to 11, and subsequently performing alkaline hydrogen peroxide bleaching in the same system using residual hydrogen peroxide.