JP3265102B2 - Cloth bleaching method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for bleaching a cloth in a dyeing factory, and more particularly to a method and an apparatus for bleaching a cloth without using a chlorine bleach.

[0002]

2. Description of the Related Art Generally, in a cloth produced by a spinning machine or a textile machine, a surfactant, a glue used for warp yarn, and the like adhere to fibers. Furthermore, since lignin, which is an untreated coloring component, remains inside the fiber, the entire cloth has a light brown color. Therefore, in order to beautifully dye this fabric in any color, it is necessary to bleach the fabric before the dyeing process. Before performing this bleaching, the steps of cutting and scouring are performed.

[0003] Accordingly, in a dyeing factory, chemicals such as oxidizing agents, chlorine-based sodium hypochlorite, and dyes are used in high concentrations and in large amounts as bleaching agents in the bleaching and dyeing processes of fabrics. In addition, since each requires a washing step, a large amount of this chemical is used, and a large amount of wastewater is generated.

A dyeing process performed in such a dyeing factory is configured, for example, as shown in FIG. The original cloth 1 supplied from the reel is removed in a demolding step 2 and the glue attached to the original cloth 1 is removed. The scoured cloth absorbs and swells the oxidizing agent in the chlorine-based oxidizing agent solution tank 4A, and the bleaching reaction is performed in the reaction tank 4B. Then, the bleached cloth is guided to the washing tank 9 in which the next washing water 10 is stored. In this washing tank 9, the organic acid, organic halogen compound and extra unreacted chlorine-based oxidizing agent generated as a result of bleaching are washed off the cloth. The contaminated cleaning water 10 is separately transferred to a water treatment facility as a cleaning drainage 11 to be treated and discharged.

Since the washing wastewater 11 contains harmful by-products and unreacted chlorine-based oxidizing agents, biological treatment is impossible. 11. the washed cloth is squeezed and dried;
Dyeing step 13. After a post-processing step 14 and a finishing step 15, the product cloth 16 is wound on a reel.

[0006]

However, the bleaching apparatus incorporated in the dyeing process shown in FIG. 4 still has the following problem to be solved, that is, in recent years, regulations on factory environment have become strict. It has become necessary to shift to water-saving bleaching and dyeing methods and to consider the quality of wastewater. In particular, when a chlorine-based chemical is used in a high concentration and in a large amount in the bleaching process, the surfactant remaining after the demolding / scouring process,
An organic halogen compound generated by reacting with an organic substance such as glue or the cloth itself causes carcinogenicity, mutagenicity, etc., and thus poses a water environment problem in a water discharge area of wastewater.

[0007] Further, since these compounds do not undergo microbial degradation and accumulate and concentrate in the environment and living organisms, the situation is regulated by the entire local environment. As the size of the dyeing plant increases, the facilities for eliminating these environmental effects become enormous, and the costs for the facilities also increase significantly.

[0008] The present invention has been made in view of such circumstances, and by using ozone, the cloth can be efficiently bleached without using a chlorine-based oxidizing agent that generates an organic halogen compound, and the ambient environment can be bleached. Bleaching method for fabrics that can prevent organic halogen compounds from being contained in wastewater discharged to wastewater, simplify the wastewater treatment process, simplify the entire equipment, and greatly reduce equipment maintenance costs And a bleaching apparatus.

[0009]

Means for Solving the Problems In order to solve the above-mentioned problems, in the method for bleaching a cloth according to the present invention, a method for producing a plant fiber cloth is described.
Impregnating with an aqueous solution adjusted to pH 3 or less with an organic acid
Thus, the cloth is allowed to absorb moisture and swell to a moisture content of 30% or more and 60% or less, and the moisture-absorbed and swollen cloth is contacted with an ozone-containing gas for bleaching, and the acid generated as a result of the bleaching is washed. .

In another aspect of the present invention , there is provided a method for bleaching a cloth, comprising the steps of: absorbing and swelling the cloth;
And bleached by contacting with an ozone-containing gas.
The subsequent cloth is irradiated with ultraviolet light, and drifted from the cloth irradiated with ultraviolet light.
The resulting acid on the white is washed away.

Another aspect of the present invention is directed to a fabric drift of the above-described invention.
In the white method, the cloth was adjusted to pH 3 or less with an organic acid.
Moisture absorption and swelling of cloth by impregnation with aqueous solution
Like that.

In another aspect of the present invention, there is provided a fabric bleaching apparatus,
Aqueous solution adjusted to pH 3 or less with organic acid on vegetable fiber cloth
By impregnating the cloth with a moisture content of 30% or more and 60% or more.
The following is a swelling tank that absorbs and swells, and an ozone-containing gas is generated.
Ozone generator and the swelling tank
Contact the cloth with the ozone-containing gas generated by the ozone generator.
Ozone bleaching tank that bleaches when touched, and this ozone bleaching tank
A washing tank for washing the acid resulting from the bleaching from the cloth.
Have.

[0013] In another aspect of the present invention, there is provided a fabric bleaching apparatus.
Impregnate the cloth with an aqueous solution adjusted to pH 3 or less with an organic acid
Swelling tank that absorbs and swells the cloth
Moisture absorption in the swelling tank with an ozone generator that generates contained gas
・ Ozone generated by the ozone generator on the swollen cloth
An ozone bleaching tank for bleaching by contacting the
Ultra-violet cloth after contacting ozone-containing gas in the Zon bleaching tank
UV irradiator that irradiates X-rays
Washing to wash acid resulting from bleaching from externally irradiated fabric
It has a clean tank.

[0014]

[0015]

[0016]

[0017]

According to the fabric bleaching method and the bleaching apparatus constructed as described above, ozone contained in the ozone-containing gas is diffused into the fibers of the moisture-swollen and swollen fabric, and the coloring component remaining in the fibers is removed. Reacts with lignin to complete bleaching. As a result, aldehydes, kents, carboxylic acids, and the like, which are easily decomposed by microorganisms, are produced as reaction by-products.

In general, ozone has a strong oxidizing power and disappears due to the self-decomposition of ozone itself, but the self-decomposition of ozone itself is accelerated by an increase in ambient temperature and irradiation of ultraviolet rays. Ozone in a solution has a higher rate of self-decomposition than gaseous ozone, and the rate of decomposition depends on the pH of the solution. That is, it is relatively stable at pH 3 or less,
In the neutral or alkaline range, autolysis proceeds rapidly.

Ozone-containing gas has been widely used as a safe drinking water purification process for the first time. Ozone-containing gas can be easily obtained at an arbitrary concentration by taking it from oxygen or oxygen cylinder in the atmospheric air.

As a result of conducting various experiments in consideration of the known properties of ozone, the inventors have found that when lignin is oxidized in the fiber, it is important that the ozone is effectively diffused into the fiber. It has been demonstrated that the fabric can be effectively bleached if the optimum conditions for promoting the oxidation reaction inside the fiber after diffusion are given.

Therefore, in the present invention, the cloth is previously absorbed and swelled to a moisture content of 30% or more and 60% or less . Therefore, the cloth can be efficiently bleached without using a chlorine-based oxidizing agent as in the conventional bleaching method, so that harmful substances are not contained in the wastewater and the amount of washing wastewater is reduced. As a result, the water treatment of the wastewater is simplified, and the wastewater can be decomposed by using microorganisms.

In the second and sixth to eighth aspects, in addition to the conditions described above, the bleaching effect is further improved by absorbing and swelling the cloth with an aqueous solution having a pH of 3 or less with an organic acid. .

Further, by raising the temperature of the cloth after contacting with the ozone-containing gas or irradiating the cloth after contacting with the ozone-containing gas with ultraviolet rays, the self-decomposition of ozone is promoted, and It has been demonstrated that the desired bleaching effect can be obtained.

[0024]

Embodiments of the present invention will be described below. Before describing the examples, experiments performed by the inventor will be described. The cotton cloth after the unrolling step and the scouring step is used as the test cloth, and the test cloth is subjected to a standard bleaching process using sodium hypochlorite and an ozone bleaching process using an ozone-containing gas. Then, the whiteness of each test cloth after bleaching was compared.

The bleaching tank has a width of 0.2 m. Prepare an acrylic box with a height of 0.1m and a length of 0.5m,
In the bleaching tank, the cloths for each experiment whose moisture content was adjusted were immersed. In the ozone bleaching treatment, the moisture content of the cloth to be tested is adjusted to pH in consideration of the purpose of suppressing the self-decomposition of ozone and the fact that the washing and drainage treatment after bleaching can be performed by a standard biological treatment method.
Adjusted with acetic acid aqueous solution of No. 3. In addition, the ozone-containing gas obtained by the ozone generator using air as a source gas is brought into pure water in order to keep the moisture content of the cloth constant, and after the aeration temperature is adjusted, the ozone-containing gas uniformly contacts the front and back of the sample cloth. Thus, it was continuously supplied into the bleaching tank at a flow rate of 0.83 liter / min.

The whiteness of the same test cloth was
The reflectance of light having a wavelength of 466 nm in a spectrophotometer was measured at three points on the cloth surface, and the average value was determined. The experimental conditions and results are shown below.

[0027] Standard techniques (conventional method) Experimental conditions bleaching tank 0.2 Experimental conditions ozone bleaching techniques x 0,1 x 0,5 m ³ bleaching tank Same available chlorine 3 g / l (pH 11.5) material gas air penetrant 0.1 ~ 0.2% Ozone concentration 20 g / Nm ³ Treatment condition 20 ℃ 4hr Treatment condition 20 ℃ 60min pH3 Water content 30,60.90%

[0028]

[Table 1]

When the whiteness of the standard method using a chlorine-based bleaching agent and the whiteness of the ozone bleaching method obtained by the experiment are compared, the whiteness obtained by the ozone bleaching method is as follows. It was carried out that was comparable to the standard method. In particular, the bleaching effect is excellent at a moisture content of 30% and a moisture content of 60%.

Further, the time required for obtaining the same whiteness is significantly reduced in the ozone bleaching method as compared with the standard method. The reason why the whiteness slightly decreases at a moisture content of 90% is that even if the free water between the fibers has a pH of 3 which is stable against the self-decomposition of ozone, the self-decomposition of ozone in the free water cannot be ignored. I think.

FIG. 1 shows a dyeing process in which a bleaching device in consideration of each condition in the experimental results is incorporated. The same parts as those in the dyeing step in which the conventional bleaching apparatus shown in FIG. 4 is incorporated are denoted by the same reference numerals. Therefore, the detailed description of the overlapping part is omitted.

The original cloth 1 supplied from the reel is removed in the demolding step 2 and the adhering paste is removed, and is refined in the next refining step 3. The scoured cloth 1 is guided into the expansion tank 4. An acetic acid aqueous solution adjusted to pH 3 is accommodated in the expansion tank 4. An aqueous acetic acid solution having a pH of 3 or less may be used.

The cloth 1 is absorbed and swelled with an aqueous solution of acetic acid adjusted to pH 3 in the expansion tank 4, and the moisture content is adjusted to 30 to 6 by the next roll squeezing air jet 5.
Adjusted to 0%.

The cloth whose moisture content has been adjusted to 30 to 60% is led to the next ozone bleaching tank 6. An ozone generator 7 is connected to the ozone bleaching tank 6. The ozone generator 7 takes in oxygen from the atmosphere or from a separately prepared oxygen cylinder, generates ozone, supplies the ozone-containing gas to the ozone bleaching tank 6, and effectively converts the ozone-containing gas into the ozone bleaching tank 6. Spread. The concentration of ozone contained in the ozone-containing gas can be easily and electrically controlled in the ozone generator 7. The cloth guided to the ozone bleaching tank 6 is bleached with an ozone-containing gas according to the principle described above.

The unreacted ozone in the ozone bleaching tank 6 is decomposed by the waste ozone decomposing device 8 and released into the atmosphere. The cloth bleached in the ozone bleaching tank 6 is led into the next washing tank 9. Cleaning water 10 is stored in the cleaning tank 9. Organic acids such as glyoxylic acid and oxalic acid and excess acetic acid generated as a result of bleaching in the ozone bleaching tank 6 are washed off the cloth by the washing water 10 contained in the washing tank 9.

The dirty washing water 10 after washing the cloth of a predetermined length is transferred to a separate water treatment facility as a washing wastewater 11 to be treated and discharged. Since the washing wastewater 11 does not contain harmful by-products or unreacted chlorine-based oxidizing agents, general biological treatment can be performed.

The washed cloth is squeezed and dried.
Dyeing step 13. After a post-processing step 14 and a finishing step 15, the product cloth 16 is wound on a reel. In the bleaching apparatus in the dyeing pretreatment step configured as described above,
Uses ozone bleaching technique. As described above, the cleaning wastewater 11 does not contain harmful by-products or unreacted chlorine-based oxidizing agents, so that general biological treatment can be performed. That is, the processing equipment for the cleaning wastewater 11 is simplified, and the equipment cost can be significantly reduced. Further, the influence on the water environment can be suppressed to a minimum.

Further, by employing the ozone bleaching method, the amount of the washing wastewater 11 can be reduced. Also,
Since the bleaching time can be reduced as compared with the standard method using a chlorine bleach, when the product cloth 16 is obtained from the original cloth 1 at the same line speed, the time for immersing the cloth in the bleaching tank is short. As a result, the length of the bleaching tank in the transport direction of the cloth can be reduced as compared with the standard method. Therefore, the entire pre-dyeing process can be downsized.

The ozone generator 7 can easily and inexpensively produce an ozone-containing gas having an arbitrary gas concentration by using oxygen in the atmosphere or an oxygen cylinder or by using electrolysis of water. Therefore, the running cost of the dyeing process can be further reduced.

The diffusion of ozone into the fibers depends on the concentration, and it is considered that the higher the ozone concentration, the more effective the bleaching. However, the ozone concentration can be freely controlled in consideration of the generation efficiency. , This ozone bleaching technique
This is advantageous compared to the standard method using a conventional chlorine bleach.

Next, the results of an experiment conducted on the effect of temperature during ozone bleaching will be described. An ozone bleaching experiment was carried out under the following experimental conditions using the cloth to be tested and the bleaching tank when the moisture content was changed as described above. And the experiment result of the whiteness shown in Table 2 was obtained.

Experimental conditions of ozone bleaching method Raw material gas Air Ozone concentration 20 g / Nm ³ Treatment conditions 30 min pH3, moisture content 60% Temperature 20, 50.80 ° C

[0043]

[Table 2]

The contact time with the ozone-containing gas was set to 30 minutes, and after the contact, the cloth to be tested was quickly taken out, and the cloth to be tested was sandwiched between metal plates having corrosion resistance controlled at the above-mentioned temperature conditions. After standing for minutes, the whiteness was determined by the method described above.

As shown in the experimental results, it can be understood that the bleaching effect is better when the temperature is set to 60 ° C. and 80 ° C. than when the temperature is set to 20 ° C. This is presumably because the self-decomposition of ozone diffused into the fibers by heating was promoted, and a good bleaching effect was obtained in a short time.

When the heating temperature is compared between 50 ° C. and 80 ° C., it can be understood that the bleaching efficiency is almost the same level, but the heating temperature of 50 ° C. is sufficient considering the operation cost of the entire equipment.

FIG. 2 shows a dyeing process in which a bleaching device in consideration of the heating conditions in the above experimental results is incorporated. The same parts as those in the dyeing process in which the bleaching apparatus of the embodiment shown in FIG. 1 is incorporated are denoted by the same reference numerals. Therefore, the detailed description of the overlapping part is omitted.

In this embodiment, a heating roller 6A, for example, in which a heater is housed, is inserted between the ozone bleaching tank 6 and the cleaning tank 9 as a heating device. The heating roller 6A is controlled at a constant temperature near 50 ° C. and not exceeding 50 ° C.

In the dyeing process thus constituted, the cloth contacted with the ozone-containing gas in the ozone bleaching tank 6 is heated to approximately 50 ° C. by the heating roller 6A. As a result, the ozone diffused into the fibers of the fabric is self-decomposed by rapid heating, and becomes oxygen radicals with strong oxidizing power. It becomes a hydroxyl radical and oxidizes and decolorizes lignin, a coloring substance.

In the embodiment, the heating roller 6A is used as the heating device, but a heating device using microwaves, infrared rays, or the like may be used. In the bleaching apparatus in the dyeing process configured as described above, since the heating roller 6A is used as a heating apparatus, the desired time can be shortened in comparison with the bleaching apparatus of the previous embodiment shown in FIG. Bleaching efficiency can be obtained.

Next, the results of an experiment conducted on the effect of ultraviolet irradiation during ozone bleaching will be described. An ozone bleaching experiment was carried out under the following experimental conditions using the cloth to be tested and the bleaching tank when the moisture content was changed. And the experiment result of the whiteness shown in Table 3 was obtained.

Experimental conditions of ozone bleaching method Raw material gas Air Ozone concentration 20 g / Nm ³ Treatment conditions 20 ° C., 30 min, pH 3, moisture content 60% UV irradiation time 10 min, 20 min

[0053]

[Table 3]

Specifically, an ozone-containing gas was brought into contact with the cloth to be tested stored in the bleaching tank for 30 minutes.
The supply of the ozone-containing gas was stopped, and two 15 W sterilizing low-pressure mercury lamps mounted on the upper part of the bleaching tank were placed on the cloth to be tested for 10 minutes and 2 cm from a position 2 cm above the cloth to be tested.
Irradiated for 0 minutes. And each whiteness was measured by the method mentioned above.

In the case of ultraviolet irradiation, a large absorption line of ozone exists at a wavelength of 260 nm, and the self-decomposition of ozone is promoted in gas, liquid, and fiber. As in the case of heating, oxygen radicals having strong oxidizing power are generated. It becomes a hydroxyl radical. for that reason,
The self-decomposition of the ozone diffused into the fiber was promoted by the irradiation of ultraviolet rays, and a good bleaching effect was obtained in a short time.

FIG. 3 shows a dyeing process in which a bleaching apparatus in consideration of the conditions of ultraviolet irradiation in the experimental results is incorporated. The same parts as those in the dyeing process in which the bleaching apparatus of the embodiment shown in FIG. 1 is incorporated are denoted by the same reference numerals. Therefore, the detailed description of the overlapping part is omitted.

In this embodiment, between the ozone bleaching tank 6 and the cleaning tank 9, an ultraviolet irradiation device 6B in which a plurality of ultraviolet lamps are incorporated is interposed. The length of the ultraviolet irradiation device 6B in the transport direction and the number of lamps are set so that the time required for each point of the cloth to pass through the inside of the ultraviolet irradiation device 6B is, for example, 10 minutes.

In the dyeing process thus constituted, the cloth contacted with the ozone-containing gas in the ozone bleaching tank 6 is
Ultraviolet irradiation is performed by the ultraviolet irradiation device 6B at intervals of 10 minutes. As a result, the ozone diffused into the fiber of the cloth is self-decomposed by ultraviolet rays, and becomes oxygen radicals with strong oxidizing power. It becomes a hydroxyl radical and oxidizes and decolorizes lignin, a coloring substance.

In the bleaching apparatus in the dyeing process thus configured, since the ultraviolet irradiation apparatus 6A is used, the bleaching apparatus of the previous embodiment shown in FIGS. And a desired bleaching efficiency can be obtained.

[0060]

As described above, in the method and apparatus for bleaching cloth according to the present invention, the cloth is absorbed and swelled to shift to an optimum state for bleaching, and then the cloth is treated with ozone. Bleached. In addition, a chlorine-based oxidizing agent that generates an organic hargen compound required by the conventional bleaching method is not used.

Therefore, the cloth can be bleached efficiently and in a short time, and the wastewater discharged into the environment can be prevented from containing an organic halogen compound. The wastewater treatment process can be simplified by using, for example, microorganisms. It is possible to simplify the entire equipment and greatly reduce the maintenance cost of the equipment.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a dyeing process in which a bleaching apparatus employing a bleaching method according to an embodiment of the present invention is incorporated.

FIG. 2 is a schematic view showing a dyeing process in which a bleaching apparatus employing a bleaching method according to another embodiment of the present invention is incorporated.

FIG. 3 is a schematic view showing a dyeing process in which a bleaching apparatus employing a bleaching method according to still another embodiment of the present invention is incorporated.

FIG. 4 is a schematic diagram showing a dyeing process in which a conventional bleaching device is incorporated.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Original cloth, 2 ... Demolding process, 3 ... Refining process, 4 ... Expansion tank, 5 ... Roll squeezing / air jet spraying, 6 ... Ozone bleaching tank, 6A ... Heating roller, 6B ... Ultraviolet irradiation device, 7
... ozone generator, 8 ... waste ozone decomposer, 9 ... washing tank, 10 ... washing water, 11 ... washing drainage, 12 ... squeezing and drying step, 13 ... dyeing step, 14 ... post-processing step, 15 ...
Finishing process, 16 ... Product cloth.

Continuation of front page (56) References JP-A-50-126997 (JP, A) JP-A-7-11565 (JP, A) JP-A-3-19961 (JP, A) JP-A-9-31840 (JP) , A) (58) Fields investigated (Int. Cl. ⁷ , DB name) D06L 1/00-3/16 D06B 1/00-23/30 C11D 1/00-19/00 D06M 10/00-11 / 84

Claims (5)

(57) [Claims] 1. A by impregnating an aqueous solution adjusted to pH3 following organic acids cloth vegetable fibers, water the fabric
Rate of 30% or more and 60% or less.
A method for bleaching a fabric, comprising contacting an ozone-containing gas with a swollen fabric to bleach the fabric, and washing the acid resulting from the bleaching. 2. The cloth is allowed to absorb moisture and swell, and the moisture absorption and swelling
The bleached cloth is contacted with an ozone-containing gas and bleached.
The cloth after the irradiation is irradiated with ultraviolet light, and the cloth irradiated with the ultraviolet light
Washing the acid generated as a result of the bleaching.
How to bleach the fabric. 3. The method for bleaching a cloth according to claim 2 , wherein the cloth is absorbed and swelled by impregnating the cloth with an aqueous solution adjusted to pH 3 or less with an organic acid. 4. by impregnating an aqueous solution adjusted to pH3 following organic acids cloth vegetable fibers, water the fabric
A swelling tank that absorbs and swells at a rate of 30% to 60% ,
An ozone generator for generating an ozone-containing gas, an ozone bleaching tank for causing the ozone-containing gas generated by the ozone generator to come into contact with the cloth absorbed and swollen in the swelling tank, and an ozone bleaching tank And a washing tank for washing the acid generated as a result of the bleaching from the cloth. 5. A swelling tank for absorbing and swelling the cloth by impregnating the cloth with an aqueous solution adjusted to pH 3 or less with an organic acid, an ozone generator for generating an ozone-containing gas, and the swelling tank. An ozone bleaching tank for bringing the ozone-containing gas generated by the ozone generator into contact with the moisture-absorbed and swollen cloth for bleaching; What is claimed is: 1. A cloth bleaching apparatus comprising: an irradiation device; and a washing tank for washing an acid generated as a result of the bleaching from the cloth irradiated with ultraviolet light by the ultraviolet irradiation device.