JPH0223628B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for desizing and bleaching woven or similar compositions based on textile fibers in a single operation in a sodium chlorite-based bath. .

It is known that the production of textiles made of cellulose fibers by dyeing, printing and other finishing treatments generally includes desizing, bleaching and optionally mercerization.

The purpose of desizing is to remove sizing agents that may have been previously applied to the warp yarns and any compounds that may have been applied to the weft yarns to improve their properties on the loom.

The sizing agent applied to the yarn before weaving may be based on starch dispersions alone or mixed with more or less chemically converted starch, or may be based on starch dispersions or derivatives of polyvinyl alcohol or polyacrylate derivatives or It can be based on etherified cellulose.

The above-mentioned sizing agents are retained in the fabric to a greater or lesser extent depending on the drying temperature, the number of twists of the yarn and the composition of the fabric.

The presence of such sizing agents makes it impossible to obtain uniform, deep shades during dyeing and printing with multiple dyes, so the sizing agents must be removed before dyeing or printing operations can be carried out.

For some knitted fabrics intended for white fabrics,
Removal of the sizing agent is also desirable to ensure that the texture of the treated product is pleasant and soft.

Desizing is generally carried out by impregnation in an enzyme and surfactant bath heated to a temperature of 60°C to 75°C. The impregnated knitted fabric should be left alone or 100%
It can be steam-treated at temperatures of 30°F. It is then washed with water at 95°C, then with water at 60°C, and optionally under running water.

The scouring is intended to saponify the grease in the cotton and solubilize the wood residues and is carried out in a caustic soda medium at a temperature of 100-140°C.

The purpose of bleaching is to oxidize impurities that are part of unbleached or already scoured cotton, linen or other cellulosic fibers. In virtually all cases oxidizing agents such as hydrogen peroxide, alkali peroxides and persalts, peracetic acid, sodium hypochlorite,
It is carried out using sodium chlorite etc.

Desizing, scouring and bleaching operations are generally carried out in an aqueous medium with heating. Each operation is followed by hot and cold cleaning, which consumes considerable water and energy.

It is an object of the present invention to reduce the number of production operations of textiles based on cellulose fibers, either by themselves or mixed with each other, or with other recycled or synthetic fibers such as viscose, polyamides and polyesters. It provides a novel method that combines desizing and bleaching in a single operation.

According to the invention, an alkali metal chlorite;
Desizing and bleaching textiles in a single operation using an aqueous bath containing a surfactant, an activator, a base consisting of an alkali metal hydroxide, and an enzyme preparation based on amylase. There is provided a method for desizing and bleaching textiles, characterized in that said aqueous bath has a pH of at least 9.2.

Suitable enzyme preparations for use in the present method are, for example, the enzyme preparations which are the object of German patent application No. P 2909396.7 and which are of the group consisting of starch-degrading enzymes such as amylases and alkyl and alkaryl oxalkylates in water. It consists of an intimate mixture with nonionic surfactants belonging to the . A suitable enzyme preparation may, for example, consist of 10 to 40 parts of an aqueous enzyme solution and 10 to 60 parts of a nonionic surfactant.

Trade name "Enthylase" by DIAMALT
Good results are obtained when using one of these enzyme preparations commercially available as (Enzylase) C. The preparation enterase C is bacterial type amylase or α-
It is based on amylase, a starch-degrading enzyme.

The process is preferably carried out by a technique consisting of: (1) impregnation of the fabric in a desizing and bleaching bath; squeezing out leaving only the amount of liquid necessary for the reaction in the fabric; This is generally between 60 and 120% by weight of the dry fabric, depending on the fabric in question.

(2) Steaming to bring the fabric to the desired reaction temperature, generally between 20 and 120°C.

(3) Placement by rolling up or placement of pleats in J-boxes, U-boxes, carpet machines, etc. for periods that can vary from minutes to hours.

The above treatment is followed by washing with water at 90-95°C, water at 60°C and cold water. The cleaning bath at 90-95℃ contains added alkaline components, caustic soda, sodium carbonate,
Trisodium phosphate and surface active detergents may advantageously be included.

One of the advantages of this method is the elimination of wet desizing operations carried out at a minimum temperature of 60-65°C and several washing baths at temperatures of 90-95°C.

Using this method also eliminates "wet-on-wet" impregnation, ie, placing the wet fabric in a bath containing a bleaching compound. It is known that this process involves a number of techniques; preparing more concentrated baths involves maintaining the impregnation bath at a constant concentration requiring either manual inspection or automatic adjustment. cormorant.

To avoid "wet-on-wet" impregnation, some users choose to feed the fabric intermediately over a drying tenter, but this requires the use of expensive equipment and virtually no This involves significant energy consumption, especially heat consumption.

Therefore, using the method of the present invention, water, steam,
This results in significant savings in labor and investment costs.

The properties of the knitted fabric thus treated are excellent;
It produces a high degree of whiteness, virtually complete removal of size agents, instant hydrophilization and a satisfactory degree of polymerization.

The following examples illustrate, but do not limit, the invention.

Example 1 Weight: 138 g/m ² , Width: 150 cm, Elreho ZEISS reflectometer, No. 8 filter,
Reflectance 49.6% measured at wavelength 457nm, glue content
After weaving a cotton knit fabric having a starch content of 7.85% and 4% and intended to be printed with reactive dyes, the following ingredients are added: 80 ml of 25% by weight sodium chlorite / activator UG45 (monosodium phosphate and Mixture with disodium phosphate; acts as a buffer to stabilize the pH so that the chlorite decomposes in a proper and regular manner) 15g/ Enthylase C 10g/ Ukanil 1036, Cleaning Wetting Agent Nonionic surfactant (mixture of _C9 - _C11 alcohol ethoxylated with 6 moles of ethylene oxide and _C11 - _C15 alcohol propoxylated with 2 moles of propylene oxide)
Direct impregnation in a bath containing 0.5 ml/ml. Add sodium hydroxide to give a PH of 9.2-9.5.

The fabric impregnated with a bath of 106% of the weight of the fabric is heated to 95° C. by steam treatment. The knitted fabric is rolled up into an insulated chamber and left to react there for 1 hour at 95°C.

After this period, the fabric is rewound and rinsed successively in a series of baths. The first bath contains water heated to 95°C; the second bath contains water heated to 95°C and 3-5 g of sodium carbonate; the third bath contains water at 60°C; the fourth bath contains water heated to 95°C; The bath contains cold water. After drying, the knitted fabric has the following properties: Reflectance (el rejo zais) 82.8% Residual starch content 0.16% Hydrophilicity Instant Example 2 Special non-woven fabric that usually requires desizing and two bleaching treatments Bleached coarse basket weave
The cotton is fluffed and then desized and bleached in a single operation.

A knitted fabric with a width of 150 cm and a weight of 180 g/m ² has a reflectance of 49.5% and a starch content of 7.25%, which is combined with the following ingredients: 25% by weight sodium chlorite 90 ml / activator UG 45 18 g / Enthylase C 10 g / Ucanil 1036 1 ml / in a bath containing.

Add sodium hydroxide to give a PH of 9.2-9.5.

The knitted fabric moves at a speed of 70 m/min and absorbs 94.5% of its own weight of bath components in the bath. The knitted fabric is passed through a steamer and heated to 85°C, then rolled up in an insulated chamber.

After reaction at 85°C for 2.5 hours, the knitted fabric was unwound,
It is then washed successively under the conditions described in Example 1.

After drying, the bleached knitted fabric has the following properties: Reflectance (El Rejo) 80.1% Residual starch content 0.18% Subsequent dyeing with reactive dyes gives excellent results.

Example 3 Immediately after weaving a knitted Hacabah cotton fabric with an unbleached reflectance of 52.8% and a starch content of 6.60%, the following ingredients were added: 27 g/activation of sodium chlorite expressed as 100% hydroxide NaClO ₂ Treat in a bath containing 14 g of sex agent UG 45 / 10 g of enthylase C / 0.5 ml of Ucanil 1036.

Add sodium hydroxide to adjust the PH to 9.2-9.5.

The knitted fabric traveling at a speed of 85 m/min is impregnated with 102% of its weight of bath components and then steam treated at 95-98°C. The knitted fabric continues to be rolled up at a temperature of 90-92°C for 2 hours. Then wash with 90°C water, 60°C water and cold water while adding sodium carbonate. After drying, the bleached textile has the following properties: Reflectance 77% Residual starch content 0.15% Hydrophilization Instantaneous Normal desizing - The bleaching process is carried out by impregnation in a bath heated to 65°C and then in an insulated chamber. Leaving it as it is will cause the glue to be removed. It is then washed with water at 95°C to 60°C and in cold water, dried on a tenter, then bleached by impregnation, steamed at 95°C, stored at 85°C for 2 hours, and washed at 95°C to 60°C. Clean with water and cold water.

Example 4 With unbleached cotton warp and cream colored linen weft, width 230 cm, weight 525 g/m ² , starch content 5.70%
Cream-colored linen-cotton mixture kebabaki,
It is then processed as follows: impregnated in a bath containing the following ingredients per 800: 25 Sodium Chlorite 105 Activator UG45 18.4 Kg Enthylase C 8.0 Kg Ucanil 1036 1.6. Add sodium hydroxide to give a PH of 9.2-9.5.

The linen/cotton mixture impregnated at a speed of 40-45 m/min absorbs 75% of its weight in a bath and proceeds to a steamer heated to 90 °C, then 85-45 m/min for 3 hours.
Roll up in a small chamber maintained at 90°C.

The knitted fabric was then processed under the same conditions as described above.
Clean at 90m/min.

After drying, the knitted fabric has the following properties: Reflectance 79% Residual starch content 0.56% Hydrophilic Instantaneous Example 5 Weight 130 g/m ² , unbleached reflectance
98 on 69.4% 65/35 polyester/cotton poplin
Impregnate a bath containing the following ingredients: 33 ml of 25% by weight sodium chlorite / 7 g of activator UG45 / 10 g of Enthylase C / 0.5 ml of Ucanil 1036 / at °C. Add sodium hydroxide to obtain a PH of 9.2-9.5.

The knitted fabric is steamed at 98°C and then held at this temperature for 1.5 hours.

It is then washed with 95° C. water with 3 g/NaCO ₃ , followed by a 60° C. water wash and then a cold water wash.

After drying, the bleached knitted fabric has the following properties: Reflectance 83.2% Residual starch content 0% Hydrophilization Instantaneous Example 6 Width 240 mm, weight 318 g per meter traveled, reflectance 59.4
%, a starch content of 7.82% by weight and intended for printing is treated in a bath containing 10 g of Enthylase C/0.5 ml of Ucanil 1036/. 100 minutes of this bath for 55 minutes
Heat to 70°C, then cool to 70°C and add next ingredients. : 3 g of 25% sodium chlorite expressed as 100% NaClO ₂ / 1.2 g of activator UG45 / Required amount of formic acid to give PH4: Heat the bath to 100° C. for 30 minutes and maintain at 100° C. for 30 minutes. The knitted fabric is drained, then hot and cold rinsed and dried on a tenter.

The desized and bleached knitted fabric thus has the following properties: Reflectance 80.3% Starch content 0 Hydrophilicity Instantaneous

Claims (1)

[Claims] 1. an alkali metal chlorite, a surfactant,
A method for desizing and bleaching textiles in a single operation using an aqueous bath containing an activator, a base consisting of an alkali metal hydroxide and an enzyme preparation based on amylase, comprising: A process for desizing and bleaching textiles, characterized in that the aqueous bath has a pH of at least 9.2. 2. The method according to claim 1, wherein the aqueous bath has a pH of 9.2 to 9.5. 3. The method according to claim 1 or 2, wherein the temperature is 20°C to 120°C. 4. The method according to any one of claims 1 to 3, wherein the knitted fabric is subjected to a steam treatment to provide the desired temperature. 5. The method according to any one of claims 1 to 4, wherein the desizing-bleaching time is from 5 minutes to 4 hours. 6. The method according to any one of claims 1 to 5, wherein the chlorite is sodium chlorite and the hydroxide is sodium hydroxide. 7. A method according to any one of claims 1 to 6, characterized in that the fabric is impregnated with an aqueous bath and then the impregnated fabric is squeezed to provide a bath component content of 60 to 120% by weight of the fabric in the fabric.