Classifications

• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06L—DRY-CLEANING, WASHING OR BLEACHING FIBRES, FILAMENTS, THREADS, YARNS, FABRICS, FEATHERS OR MADE-UP FIBROUS GOODS; BLEACHING LEATHER OR FURS
  • D06L4/00—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs
  • D06L4/10—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which develop oxygen
  • D06L4/13—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which develop oxygen using inorganic agents

Definitions

• Cold-bleached cotton fibers suffer one major disadvantage, however. Their absorbencies, that is their abilities to be wetted with water, are poor. This means that they are not readily receptive to many post-bleaching treatments; as an example, they are difiicult to dye.
• the bleached fibers of the present invention exhibit this improved absorbency without any sacrifice in the other desirable properties of cold-bleached fibers.
• the bleached fibers of the present invention do not undergo undue degradation, and they do not contain undue amounts of harmful impurities. It has even been found that they exhibit somewhat improved brightnesses when compared with fibers bleached by the same technique, with a hydrogen peroxide bleaching solution not containing the dipersulfate.
• Cotton fibers in any form, and either alone or mixed with other fibers, may be treated by the present method.
• the fibers may be raw stock, or they may be carded, spun, woven, knitted, felted, or otherwise fabricated into goods.
• the fibers are dampened with'the present bleach solution. In damp condition, they contain about 50 to 150 parts by weight of bleach for each parts by weight of fiber. Dampened fibers containing 100 parts by weight of bleach for each 100 parts by weight of fiber are referred to herein as being dampened to the extent of 100 percent.
• the dampening of the fibers is carried out by conventional means. For example, they may be immersed in the bleach bath, removed from the bath, and squeezed to remove excess bleach. Other suitable means will be apparent to one skilled in fiber-treating.
• the bleaching operation is carried out at a temperature at or near room temperature, for example, at about 50 F. to 5., over about 6 to 24 hours. Some heat of reaction is given off in the bleaching operation, and may raise the temperature of the dampened fibers to as much as about 120 F. or even slightly higher. This has been found not to interfere with the bleaching operation.
• the fibers normally are kept damp; that is the bleach solution is maintained in the fibers in the amount of about 50% to While the bleach solution may be permitted to evaporate from the fibers to provide somewhat less than 50% saturation during bleaching without destroying the bleachrug efiiciency, the more sensitive cotton fibers may be damaged by the more concentrated alkaline bleach solution which results from excess evaporation, and it therefore is preferred to maintain at least about 50% of bleach liquor in the fibers.
• the desired degree of dampness may be maintained readily, by merely stacking the fibers to retard evaporation of the bleaching solution.
• Other means for maintaining the fibers in damp condition may be employed, for example, they may be stored in humid atmosphere, or they may be covered to prevent or retard evaporation.
• the fibers are washed free of bleaching solution with water, at room or elevated temperatures.
• the bleach solution comprises a typical hydrogen peroxide cold-bleach solution, containing as an added, essential ingredient, about 3 to 15 grams per liter, and preferably about 5 to 7 grams per liter, of a dipersulfate of ammonia or an alkali metal.
• the aqueous alkaline hydrogen peroxide bleach solution normally will contain, in addition to the dipersulfate, about 0.75 to 5% by weight of hydrogen peroxide, about 5 to 25 grams per liter of sodium hydroxide, or an equivalent amount of another alkalisuchas potassium hydroxide or an alkali phosphate, and a stabilizing amount of a typical bleach bath stabilizer such as sodium silicate or a phosphate.
• a stabilizing amount of the silicate is about to 50 grams-per liter, and of the phosphate is about 2 to 15 grams per liter.
• this solution Will also contain a wetting agent of the type normally used in bleach ing solutions, preferably a non-ionic or anionic wetting agent such as an alkyl aryl sodium sulfonate or an alkyl aryl polyether alcohol, in the amount of about 1 to 5 grams per liter, Hydrogen peroxide and alkali may be place part of the hydrogen peroxide for bleaching, as
• the bleaching solution containing the dipersulfate should not undergo prolonged heating above about 100 F.before application to the fibers, as such preheating reduces the effectiveness of the dipersulfate in improving the absorbencies and brightnesses of the fibers in bleaching. Heating the dampened fibers containing the bleach to about 120 F. or even higher, however, does not have this deleterious effect.
• the brightnesses of the bleached fibers were determined on a Gardner Automatic Multi-Purpose Reflectrometer, manufactured by Gardner Laboratory, Inc., of Bethesda, Maryland. Brightnesses of 80% or better are considered satisfactory.
• the absorbencies of the fibers were measured by placing a sample of the cloth in taut condition on a horizontal frame, dropping one drop of distilled water from a height of /8 inch onto the cloth, and measuring the time for disappearance of a specular reflection from the water. Time values of to seconds or less are considered satisfactory.
• Fluidities a measure of the extent of damage to the fibers, were measured by the ASTM Cuprarnmonium Method, D-539-53, with the results being stated as rhes units. Rhes values on the order of about 6 to 7 or lower are considered satisfactory.
• the fibers also were tested for ash, for their contents of water-extractable materials, their contents of enzymeextractable materials, and for their contents of fats, oils and waxes, by standard techniques. These additional determinations were made to compare the general properties of fibers c01d-bleached with solutions containing, and those not containing, the dipersulfate. The ash determinations were made by charring samples of cloth in a platinum crucible using a Mekker burner, and mufiling to constant weight. Ash values on the order of 20% to .25% or lower are considered satisfactory. The percent enzyme-extractable values were determined with a solution of Rapidase, a proteolytic enzyme sold by Penetone Co., of Tenafly, New Jersey.
• Example 1 Swatches of cotton drill cloth, having a weight of 1.85 yards per pound and a reflectance of 63% was immersed in following solutions A and B, and passed, through rollers to adjust the content of bleach solution on the cloth to 100%. The samples were then packed into, a vessel and covered with a further cloth containing the bleach solution, and permitted to stand for 19 hours at room temperature, about 75 -F. to F. The treated fibers were then washed free of bleach solution by three water washings and dried in an air circulating oven at 200 F. The bleached samples were then tested, with the results reported under the heading Cloth Analysis.
• the amount of sodium silicate reported in the various examples is the amount of 42 B. solution employed.
• the detergent used in the various examples was an alkyl aryl sodium sulionate.
• Example 2 The procedure of Example 1 was repeated, employing the following bleach solutions:
• Example 3 The procedure of Example 1 was repeated, employing the following bleach solutions:
• Swatches of the cloths treated with solutions A and B were washed and tested after being stored for 6 hours.
• the swatches treated with solution A had a reflectance of 79.9% absorbencies of over 3 minutes.
• the swatches treated with solution B had reflectances of 82.0%, and absorbencies of only seconds.
• Example 4 the cloth treated was an 80 x 80 thread cotton print cloth, having a weight of 4 yards per pound.
• cotton fibers bleached with the present dipersulfate-containing cold-bleach solutions have better brightnesses, and much better absorbencies, than similar fibers treated with typical cold-bleach solutions not containing a dipersulfate.
• These improvements are achieved with no increase in the active oxygen content of the bleaching bath, and with no substantial change in other properties of the bleached cloth.
• These improved bleaching results make the cold-bleaching method suitable for bleaching cotton fiber products which must have high absorbencies, and thereby bring the economic advantages of the cold-bleach process into this area of fiber bleaching.
• the improvement which comprises employing as the bleaching bath an aqueous alkaline hydrogen peroxide solution containing as an essential ingredient, a dipersulfate from the group consisting of the alkali metal dipersulfates and ammonium dipersulfate, whereby the absorbency of said cotton fibers is not materially diminished.
• Method of claim 2 in which the bleach comprises about 0.75% to 5% by weight of hydrogen peroxide, about 3 to 15 grams per liter of a dipersulfate from the group consisting of the alkali metal dipersulfates and ammonium dipersulfate, an amount of alkali equivalent to about 5 to 25 grams per liter of sodium hydroxide, and a stabilizing amount of a stabilizer.
• dipersulfate is potassium dipersulfate.

Landscapes

• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)
• Detergent Compositions (AREA)
• Treatment Of Fiber Materials (AREA)

Priority Applications (4)

Applications Claiming Priority (1)

Publications (1)

Family

ID=25294935

Family Applications (1)

Country Status (3)

Cited By (4)

Citations (4)

• 0
  • BE BE595566D patent/BE595566A/xx unknown
• 1959
  • 1959-10-09 US US845310A patent/US3026166A/en not_active Expired - Lifetime
• 1960
  • 1960-09-29 GB GB33430/60A patent/GB894070A/en not_active Expired

Patent Citations (4)

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