FR2498649A1 - PROCESS FOR DEBUNCHING AND BLEACHING TISSUES IN A SINGLE OPERATION IN A SODIUM CHLORITE BATH - Google Patents

Abstract

PROCESS FOR DE-SIZING AND BLEACHING FABRICS IN A SINGLE OPERATION IN A BATH CONSISTING OF SODIUM CHLORITE, SODIUM HYDROXIDE, AN ACTIVATOR, AN ENZYMATIC PREPARATION BASED ON A STARCH DEGRADATION ENZYME AND A TENSIO AGENT -ACTIVE. THE PROCESS OF THE INVENTION WHICH COMBINES IN A SINGLE OPERATION THE DE-BONDING AND THE BLEACHING OF THE FABRICS ALLOWS SIGNIFICANT SAVINGS IN WATER, STEAM, LABOR AND INVESTMENT.

Description

_ 1 _

  The present invention relates to a method for

  sizing and bleaching in a single tissue operation

  or similar compositions based on textile fibers.

  It is known that the preparation of tissues

  celluloses for dyeing, printing and other finishing processes generally include desizing, scouring, bleaching and

possibly mercerization.

  The purpose of the desizing is to eliminate the sizing agents previously applied to the warp yarns in order to promote their behavior on the loom, as well as

  that the products possibly applied to the weft threads.

  The sizing products of the yarns before weaving may be based either on starch dispersions alone or

  mixed with starches more or less chemically modified

  either from polyvinyl alcohol derivatives or from

  polyacrylate derivatives, or etherified cellulose.

  Sizing products may be more or

  less restrained in the fabric according to the drying temperature

  age, twisting of the thread and the texture of the fabric.

  The presence of such products prevents, during the

  dyeing and printing with many dyes, the ob-

  a uniform and solid shade, and it is necessary to eliminate them before proceeding with the dyeing operations

or print.

  For certain fabrics intended for sale in large white, the elimination of sizing is also desired in order to give the treated goods a pleasant touch

and flexible.

  Desizing is usually done by means of

  Pregnancy in a bath of enzymes and heated surfactant

  at a temperature between 601C and 751C. The tissue

  prégné can be either left in storage or vaporized at a temperature of 1000C. It is then washed at 951C and then

  600C and possibly with running water.

  Scouring, which aims to saponify the cotton fat and solubilize the wood residues, is carried out in caustic soda medium and

  temperature between 1001C and 140'C.

  The purpose of bleaching is to oxidize impurities

  which are part of the raw fiber or already dumped of co-

  flax, flax or any other cellulosic fiber. he

  in practically all cases with

  such as hydrogen peroxide, alkaline peroxides and persalts, peracetic acid, hypochlorite

  sodium, sodium chlorite, etc.

  The operations of desizing, scouring, bleaching are generally carried out in an aqueous medium and hot. Each of them is followed by hot and cold washes resulting in significant consumption

of water and energy.

  The present invention aims to reduce the

  number of tissue preparation operations based on

  cellulosic fibers, alone or mixed with one another or with other regenerated or chemical fibers, such as viscose,

  polyamides and polyesters and provides a new

  assigned in which desizing and bleaching are com-

in one operation.

  The desizing-bleaching process in one

  the operation of the present invention is carried out in a

  bath comprising sodium chlorite, a base such as

  sodium hydroxide, optionally an activating agent, an enzymatic preparation based on a degradation enzyme

  starch and a surfactant.

  An enzymatic preparation that can be used according to the

  vention may for example be constituted by Enzylase C, trademark of the DIAMALT Company, subject

  of the German patent application P 29 09 396.7.

  The application of the process is preferably carried out according to the technique comprising:

  1) Impregnation of the fabric in the desiccant bath

  bonding and bleaching; expressing to leave in the fabric only the amount of bath necessary for the reaction. She

  is generally between 60 and 120% of the weight of

su dry according to the considered fabric.

  2) Spraying to bring the fabric to the temperature

  desired reaction rate generally between 20.degree.

and 120 ° C.

  3) Deposition by winding or folds in J-Box, U-Box, carpet machine ... for a time that can vary from a few

minutes to several hours.

  The treatment is followed by washing at 900 - 95 ° C,

  600C and cold. The wash bath at 90 - 951C can be

  gement with the addition of alkaline elements, caustic soda, sodium carbonate, trisodium phosphate and

  than surfactant detergent agents.

  One of the advantages of the process according to the invention is to eliminate a wet desizing operation carried out at a minimum temperature of 600-650 ° C, as well as

  several wash baths at temperatures of 900 - 951C.

  The application to the process also removes a

  "wet-on-wet" impregnation, that is to say wetting

  entering a bath containing bleaching products.

  It is known that this treatment results in a number of

  T: Preparation of a more concentrated bath, keeping the impregnation bath level and at constant concentrations, which implies either a manual control or an automatic control. To avoid "wet-on-wet" impregnation, certain applicators do not hesitate to make an intermediate passage on a dryer train which leads to the use

  expensive equipment and high energy consumption.

mainly heat energy.

  The adoption of the process according to the invention therefore results in significant savings in water, steam,

manpower and investment.

  The characteristics of the fabric thus treated are

  excellent: high degree of whiteness, removal of

  almost total age, instantaneous hydrophilicity, degree of

cured polymerization.

  The following examples illustrate the invention of

non-limiting way.

EXAMPLE 1

  A slender cotton fabric of 138 gr / m2, width of

  centimeters, reflectance 49.6%, measured with reflect-

  ELREPHO ZEISS, filter no. 8, wavelength 457 nanometers,

  sizing rate 7.85%, starch content 4%, intended for

  pressure in reactive dyes was directly impregnated at the weaving outlet in a bath containing: - Sodium Chlorite 25% by weight ...... 80 ml / l, - Activator UG 45 ......... .............. 15 gr / l, - Enzylase C ....

  ..................... 10 gr / l, .. DTD: - Ukanil 1036, wetting detergent ...... 0.5 ml / l.

  Sodium hydroxide is added in order to

set the pH at 9.2 - 9.5.

  The fabric impregnated at 106% of its bath weight

  is vaporized at a temperature of 95 ° C.

  He is wrapped in an insulated room where he

  remains in reaction at 95 ° C. for 1 h 30 min.

  After this time, it is unrolled and rinsed with

  tinu in a series of tanks: the first contains water heated to 950C; the second contains water heated to 950C and carbonate of soda: 3 - 5 gr / l; the third contains water at 60 C; the fourth contains cold water. After drying, the characteristics of the fabric are the following: - Reflectance ELREPHO ZEI55 ....... 82.8%,

  - Residual starch content .......... 0,16%.

- 5 -

- Instant hydrophilic.

EXAMPLE 2

  A woven cotton fabric particularly gray and soft and which usually requires a desizing and two bleaching treatments was submitted after buckling

  to desizing-bleaching, in one operation.

  The fabric in 150 centimeters width, weight per m2 gr, reflectance 49.5%, starch rate 7.25%. It has been impregnated in a bath containing: - sodium chlorite 25% by weight .... 90 ml / l, - Activator UG 45 ..................... ...

  ... 18 gr / l, - Enzylase C .......................... 10 gr / l, .. DTD: Ukanil 1036 .. ...................... 1 ml / l.

  Sodium hydroxide is added to fix the

pH at 9.2 - 9.5.

  The fabric has grown to a speed of 70 meters / minute

  you and took away 94.5% of its bath weight. It was heated to 85 C by passage in a vaporizer, then was wound in

insulated room.

  After reaction for 2 h at 85 ° C., it was unrolled and then washed continuously under the conditions indicated in

example n 1.

  After drying, the characteristics of white

  chi are the following: - Reflectance ELREPHO ........... 80.1%,

  - Residual starch content ........ 0.18%.

  Subsequent dyeing with reactive dyes

gave excellent results.

EXAMPLE 3

  Hacabah cotton fabric, reflectance in off-white 52.8%, starch content 6, 60%, was treated directly after weaving in a bath containing: Sodium chlorite expressed in 100% NaClO. 27 g / l , - Activator UG 45 .....

  ....................... 14 gr / l, - Enzylase C ................... .......... DTD: ..... 10 gr / l, .. DTD: - Ukanil 1036 ..................... ................... 0,5 ml / l.

  Sodium hydroxide is added to fix the

pH at 9.2 - 9.5.

  Fabrics passed at a speed of 85 meters / minute

  were impregnated at 102% of their bath weight after

  porisage at 95 - 98 ° C. They were kept coiled for 2 hours at a temperature of 90 ° -92 ° C. They were then washed at 90 ° C. with the addition of sodium carbonate at 60 ° C.

  and cold. After drying, the characteristics of the white fabric

  chi are the following: - Reflectance ................. 77%,

  Residual starch rate 0.15%.

- Instant hydrophilic.

  The usual treatment involves desizing by

  impregnation in a heated bath at 65 C then deposit in a room

  lorifugée. Washing at 950C - 60 C and cold. Rowing drying

  then bleaching by impregnation. Spray at 95 C and,

  at 85 ° C. for 2 hrs. Washing at 95 ° C.-60 ° C. and cold.

EXAMPLE 4

  A cream-colored half-linen fabric, unbleached cotton, cream linen fabric, width of 230 centimeters, weight per square meter 525 gr,

  starch content of 5.70%, was flamed and then treated in the

following lesson:

  Impregnation in a bath containing for 800 liters.

  - 25% Sodium Chlorite ........ 105 1, - Activator UG 4 5 ..............

  ... 18.4 kg, - Enzylase C ....................... 8.0 kg, .. DTD: - Ukanil 1036 .... ............ 1.6 1.

  Sodium hydroxide is added to fix the

pH at 9.2 - 9.5.

  - 7- The fabric impregnated at the speed of 40 - 45 meters / minute causes 75% of its weight of bath, it passes in a vaporizer heated to 90oC, then is left wound in a

  room maintained at 850 - 90 ° C for 3 hours.

  It is then washed at 90 meters / minute in

  conditions similar to those described above.

  After drying, the characteristics of the fabric are as follows: Reflectance .................. 79%, - Residual starch content ....... 0.56 %

- Instant hydrophilic.

EXAMPLE 5

  65/35 polyester / cotton poplin, weight per gr 2, ecru 69, 4% reflectance. It has been impregnated to 980C of its weight with: - Sodium chlorite at 25% of its weight .. 33 ml / 1, - Activator UG 45 .................. ........ 7 gr / l, - Enzylase C ........................... 10 gr / l,

  - Ukanil 1036 ............., ......... 0.5 ml / '.

  Sodium hydroxide is added to fix the

pH at 9.2 - 9.5.

  The fabric was sprayed at 98'C and then maintained at this

temperature for 1 h 30.

  It was then washed with water at 95 C with Na2Co3:

  3 gr / l, then water at 60 C and cold.

  After drying, the characteristics of the white fabric

  chi are: - Reflectance .................... 83.2%, - Residual starch content ........ O%,

- Instant hydrophilic.

EXAMPLE 6

  A cotton fabric for sheet for printing, width of 240 centimeters, weight per meter running 318 grams, - 8 - reflectance 59.4%, starch content 7.82% of the weight of the fabric, was treated in a bath containing: - Enzylase C ................... 10 gr / l,

  - Ukanil 1036 ................... 0.5 ml / 1.

  The bath is heated at 100 ° C. for 55 minutes and then cooled to 70 ° C., it is added: sodium chlorite of 25%, expressed as 100% NaClO 2.

  .... 3 gr / l, - Activator UG 45 .................... 1,2 gr / l, .. DTD: - Formic acid for ph4.

  The mixture is heated for 30 minutes at 100.degree.

  hold at 100 C for 30 minutes. We empty, then we rinse

  hot and cold and dry on oars.

  The fabric thus desized and bleached has the characteristics

  following characteristics: - Reflectance .................. 80.3% - Starch content ............... 0

- Instant hydrophilic.

- 9 -

Claims (1)

CLAIM   Method for desizing and bleaching tissues in a single operation in a bath comprising sodium chlorite, a base such as sodium hydroxide, an activating agent, an enzymatic preparation based on an enzyme   of starch degradation and a surfactant.