JPH0680231B2 - Fabric bleaching method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a bleaching method for a long fabric, which is capable of continuously and rapidly bleaching a fabric.

[Prior Art] Conventional sodium chlorite bleaching of long fiber fabrics that are continuously processed and produced industrially applies an aqueous solution of sodium chlorite activated by an organic acid or an inorganic acid to a fabric to be bleached. Then, the liquid-containing cloth is then fed into the moist heat reaction treatment chamber to continuously perform the intended bleaching treatment. More specifically, the conventional bleaching method of this kind will be described. The aqueous solution of sodium chlorite to be applied to the cloth to be bleached is adjusted to pH 3 to 4, and the cloth is continuously passed through the aqueous solution. After soaking, it is compressed by a squeezing roll so as to have an appropriate liquid content, and then the fabric is steamed in a moist heat reaction chamber or kept at 80 to 90 ° C. in the liquid for about 40 to 60 minutes for a long time. The wet heat reaction treatment is carried out for the purpose of continuous bleaching of the intended long fabric. That is, in the means for loading in the reaction chamber, a difference in temperature distribution and reaction rate between the inside and the outside of the loaded cloth occurs, and it is necessary to match the portion where bleaching is most delayed, so it takes about 40 to 60 minutes. It requires a long processing time.

[Problems to be Solved by the Invention] However, in such a conventional bleaching method, the timing of the wet heat reaction of the fabric containing the aqueous solution of sodium chlorite requires about 40 to 60 minutes as described above. From doing
In order to secure the moist heat treatment time, since the cloths fed into the reaction chamber are sequentially loaded in the above-mentioned moist heat reaction chamber, wrinkles are generated on the cloth due to the stacking pressure, and uniform and good bleaching is achieved. It was something I couldn't expect. In particular, when the cloth to be bleached is a high-grade product such as a high-density fine-count woven fabric or a strongly twisted yarn woven fabric, it is impossible to correct the crease once it becomes crease. Such a bleaching process in which a product pressure is applied in a moist heat reaction chamber must be avoided.

Therefore, in order to transfer the cloth in the reaction chamber without applying a product pressure during the wet heat treatment of the cloth, it is possible to adopt a guide roll transfer means. However, in the continuous transfer means of the cloth using the guide roll, The number of guide rolls to be arranged in the moist heat reaction chamber becomes large, and the entire reaction chamber becomes enormous. That is, when the cloth to be subjected to the moist heat reaction is required to stay in the reaction chamber for 40 to 60 minutes, for example, 1
If the processing speed per minute is 100 m, it will be 4000-6000 m.
This requires a group of guide rolls capable of accommodating the cloth and a volume of the wet heat reaction chamber, which makes the wet heat reaction chamber enormous, and it is practically difficult to install such a large wet heat reaction chamber.

[Means for Solving the Problems] The present invention has been made in view of the above circumstances. If the bleaching reaction time in the wet heat reaction chamber of the fabric to be bleached can be shortened, the fabric to be treated is It was made paying attention to the fact that it is possible to perform bleaching processing without wrinkles by using a guide roll transfer means that does not generate wrinkles.

That is, the present invention is to improve the means for applying the chemical liquid to the cloth, and to significantly shorten the reaction time in the wet heat reaction chamber. In other words, as a method of shortening the treatment time of the sodium chlorite bleaching of the fiber cloth, a method of lowering the pH, a method of increasing the liquid ratio, a method of increasing the treatment temperature, a method of increasing the concentration of the bleaching agent, a uniform heat distribution There is a method to do it in the state, but with either method, bleaching in 2 minutes is insufficient,
At least 10 minutes of treatment is required. In contrast,
In the present invention, in order to shorten the bleaching reaction time in the moist heat reaction chamber, saturating the bleaching solution on the fabric is repeated twice, and the fabric is heated and heated in the steam atmosphere between the first and second times. When warmed and steamed, a bleached fabric having a whiteness comparable to that of the conventional bleaching for 40 to 60 minutes was obtained in 2 minutes. First, as a first means, the cloth is impregnated with an aqueous solution of sodium chlorite adjusted to the acidic side at room temperature and squeezed with a squeeze roll, and immediately after that, the cloth is heated in a steam atmosphere as a second means,
As the third means, the same aqueous solution of sodium chlorite as in the first means is re-impregnated from room temperature at a natural temperature rising condition brought in by the cloth, then squeezed with a squeezing roll and steamed in a steamer for transferring guide rolls for rapid bleaching. It is something that is processed. The reason why bleaching progresses rapidly is that the bleaching agent applied by the first means accelerates the penetration of the bleaching agent into the inner core of the fabric by the moist heat heating of the second means, and the activity of sodium chlorite is activated, resulting in the formation of chlorite gas. When the bleaching solution is about to be released into the air, the bleaching solution of the third means suppresses the chlorous acid gas to be released, so that the bleaching agent is activated in the fabric without waste, so that the bleaching can be performed quickly.

Therefore, by adopting the bleaching method of the present invention, the cloth transfer means in the moist heat reaction chamber can perform tension transfer of the cloth by the guide rolls, so that a high quality bleached cloth can be obtained without causing creases or the like in the cloth. The feature is that it can be produced.

Hereinafter, the present invention will be described in detail based on the embodiments shown in the drawings.

1 is a long cloth to be bleached, and this cloth 1 is first supplied into a first bleaching solution dipping tank 2. In the first bleaching solution dipping tank 2, an acid-activated sodium chlorite solution adjusted to pH 3.5 to 4.0 at room temperature is impregnated. The liquid-containing cloth that has passed through the first bleaching solution dipping tank 2 is squeezed by a squeeze roll 3 and then steamed for about 6 seconds in a heating chamber 4 that is steam-heated to about 100 ° C. . The steam-heat treated cloth is supplied into the second bleaching solution dipping tank 5,
In the second bleaching solution dipping tank 5, the first bleaching solution dipping tank 2 is used.
A room-temperature acid-activated sodium chlorite solution similar to the above is applied together with the temperature that follows the cloth temperature carried by the cloth. This second
The fabric re-immersed in the bleaching solution dipping tank 5 of No. 1 is passed through the squeeze roll 6 and then supplied into the atmospheric steamer 7 which is heated to near 100 ° C., and the wet heat reaction treatment is carried out in the atmospheric steamer 7. And the desired bleaching is done. According to this embodiment, the steaming treatment time in the atmospheric pressure steamer 7 is about 2 minutes for bleaching to obtain the desired whiteness. Therefore, the guide means for the cloth in the atmospheric pressure steamer is used as a guide roll. Even if the transfer means using 8 is used, it is not necessary to enlarge the atmospheric steamer 7 to the left, and therefore, the transfer means using the guide rolls 8 does not exert a product pressure on the cloth and bleaching treatment with good quality. A fabric is obtained.

Next, the following results were obtained as a result of comparing the bleach-treated cloth of the method of the present invention performed using the bleach-treatment apparatus of the above-mentioned example with the bleach-treated cloth by another method.

[Example] 100% cotton fabric Was subjected to scouring and scouring according to a conventional method, and bleaching treatment was performed as follows to compare the effects of the present invention.

Bleach Recive Sodium chlorite 1%, nonionic activator 0.
The pH was adjusted to 2.6 by adding 0.24% phosphoric acid to 2%.

(1) Method of the present invention The cloth is dipped in a room temperature bleaching solution, squeezed to 100% with a squeezing roll, heated to 70 ° C through a steam atmosphere, again immersed in the bleaching solution, squeezed to 100% with a squeezing roll, and steamed for 2 minutes. It was washed with water, desalted with sodium thiosulfate and dried.

(2) Comparative Example 1 A cloth was dipped in a bleaching solution at room temperature, squeezed to 100% with a squeezing roll, repeated twice for 2 minutes, steamed for 2 minutes, desalted with sodium thiosulfate and dried.

(3) Comparative Example 2 A cloth was dipped in a bleaching solution at room temperature, squeezed to 100% with a squeezing roll, steamed for 2 minutes, washed with water, desalted with sodium thiosulfate, and dried.

・ Whiteness was calculated from the Taube formula by measuring the color with a spectrophotometer.

Method of the Invention Whiteness 84.2 Comparative Example 1 Whiteness 71.8 Comparative Example 2 Whiteness 67.5 [Effect of the Invention] From the above results, according to the present invention, the steaming time in the atmospheric steamer is as short as about 2 minutes. However, it is possible to obtain a very effective bleached cloth, and therefore the cloth transfer means for running in the steamer for steam heat treatment can be continuously transferred using guide rolls, and the loading method can be eliminated. Even with a steamer that uses rolls, the processing time is short, so the overall shape of the steamer can be downsized. Therefore, steamers with guide rolls can be used. It is possible to obtain an effect that a high-quality bleached cloth that does not cause wrinkles and the like can be obtained.

[Brief description of drawings]

The drawings are explanatory views showing an example of an apparatus for carrying out the bleaching method of the present invention. 1 ... Cloth, 2 ... First bleaching solution dipping tank 3 ... Squeezing roll, 4 ... Heating chamber 5 ... Second bleaching solution dipping tank 6 ... Squeezing roll, 7 ... Normal pressure steamer 8 ... … Guide roll

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location D06B 15/00

Claims (1)

[Claims] 1. A fiber cloth is dipped in an acid-active sodium chlorite solution at room temperature, squeezed and immediately passed through a steam heating chamber to raise the temperature of the cloth. A method for bleaching a cloth, which comprises immersing the cloth in a sodium chlorate solution again, pressing the same, and then performing steaming heat treatment in a steamer.