Classifications

• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06P—DYEING OR PRINTING TEXTILES; DYEING LEATHER, FURS OR SOLID MACROMOLECULAR SUBSTANCES IN ANY FORM
  • D06P1/00—General processes of dyeing or printing textiles, or general processes of dyeing leather, furs, or solid macromolecular substances in any form, classified according to the dyes, pigments, or auxiliary substances employed
  • D06P1/0024—Dyeing and bleaching in one process
• • 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

• a method for bleaching textile fabrics containing portions dyed with a sensitive dyestutf involving subjecting such a fabric to the action of a bleaching solution comprising an aqueous solution of a peroxymonosulfate at a concentration to provide from 0.005% to -l% active oxygen, which solution contains a buffering agent effective to maintain the pH of the solution at a value within the range 5 to 8.5.
• a bleaching solution comprising an aqueous solution of a peroxymonosulfate at a concentration to provide from 0.005% to -l% active oxygen, which solution contains a buffering agent effective to maintain the pH of the solution at a value within the range 5 to 8.5.
• the fabric is saturated with such a solution and the saturated fabric is then heated, e.g., by steam, for a time of from 5 minutes to 20 hours to effect the bleaching.
• the bleaching solution employed in practicing the method of the invention is an aqueous solution containing a peroxymonosulfate in an amount such as will provide in the solution a concentration of active oxygen of from 0.005 to 1%.
• a peroxymonosulfate in an amount such as will provide in the solution a concentration of active oxygen of from 0.005 to 1%.
• Any of the water soluble peroxymonosulfates such as the alkali metal peroxyfinonosulfates, ammonium peroxymonosulfate or the alkaline earth metal peroxymonosulfates, can be employed.
• the most preferred peroxymonosulfate is the potassium peroxymonosulfate triple salt compound of the formula KHSO; K 50 2KHSO A product comprising such triple salt compound and containing about 4.7% active oxygen by weight is 'available commercially.
• the peroxymonosulfate component of the solution can also be formed in situ in the solution by the reaction of peroxymonosulfuric acid, also called Caros acid, H 50 and an alkali such as caustic soda,
• the concentration in the solution of active oxygen derived from the peroxymonosulfate will range from 0.005 to 0.02% for immersion bleaching, and from 0.03 to 0.2% for saturation bleaching.
• the peroxymonosulfate bleaching solution should be buffered to a pH within the range 5 to 8.5, preferably 5.5 to about 7. If the pH is lower than about pH 5, the solution may be sufficiently acidic to damage cellulosic fabrics. On the other hand, if the solution has a pH substantially higher than about 8.5, the solution becomes less stable.
• excellent bleaching of the undyed portions of the fabric i.e., the white background portions, occurs with little or no bleeding of dyes from the dyed portions resulting and, consequently, with little or no staining of the undyed portions or mark-off onto such undyed portions.
• the commercially available peroxymonosulfate triple salt product is quite acidic so that solutions thereof will generally require at least partial neutralization with an alkaline material in order to bring the pH of the solution within the range pH to 8.5, most preferably 5.5 to 7.
• Such adjustment of the pH can be effected by the addition of any of the common alkalies such as sodium, ammonium or potassium hydroxide, or various alkaline salts, but it is also generally desirable that a salt having buffering properties such as to maintain the pH within such a range during the entire bleaching operation be also present.
• alkali metal phosphates particularly tetraalkali metal pyrophosphates such as tetrasodium pyrophosphate, are particularly effective for this purpose although other buffering agents such as sodium bicarbonate, the combination of borax and phosphoric acid or of tetrasodium pyrophosphate and sodium acetate may also be used.
• buffering agents such as sodium bicarbonate, the combination of borax and phosphoric acid or of tetrasodium pyrophosphate and sodium acetate may also be used.
• bleaching with such solutions may be effected at ordinary temperatures, it generally will be preferred to employ somewhat elevated temperatures in order to de- Crease the bleaching time required.
• bleaching will generally be-effected at a temperature of at least 100 F., e.g., temperatures from 100 F. up to as high as about 212 F. At such temperatures, bleaching times ranging from about minutes to 5 hours may be employed, the higher temperatures generally requiring shorter times than lower temperatures.
• Bleaching may be effected by immersing the fabric in the bleaching solution maintained at the desired temperature, but preferably the fabric will be impregnated or saturated with an amount of the bleaching solution equal to from about 50% to 150%, preferably 80-120%, of the fabric weight, and the saturated fabric will then be heated at the desired temperature, e.g., by contacting it with live steam or a mixture of steam and air, depending upon the temperature desired.
• the desired temperature e.g., by contacting it with live steam or a mixture of steam and air, depending upon the temperature desired.
• the fabric samples employed in the examples were in tightly braided form and each sample was saturated with the designated bleaching solution and the saturated sample was then bleached in a chamber containing live steam or a mixture of live steam and air to get temperatures above 175 F., or placed in a covered beaker immersed in a water bath maintained at the desired bleach temperature to get temeratures below 175 F. Following bleaching, the samples were unbraided and rinsed well with hot water at least three times.
• DTPA designates a commercial diethylenetriaminepentaacetic acid sequesterant
• TSPP designates tetrasodium pyrophosphate decahydrate
• PMS designates the commercially available potassium peroxymonosulphate product comprising the triple salt KHSO -K SO -2KHSO having an active oxygen content of about 4.7%.
• Bleaching solutions containing peracetic acid were formulated using the commercially available peracetic acid solution.
• a continuous length of the fabric to be bleached will be continuously saturated with the bleaching solution, following which the saturated fabric will be continuously heated by contact with steam or a mixture of steam and air and the heated fabric then stored, e.g., in a J-box or other equipment, from which it can be continuously withdrawn after a residence therein equal to the desired bleaching time.
• the method of the invention is applicable to the bleaching of fabrics containing portions dyed with naphthol dyes, disperse dyes, vat dyes and copper phthalocyanine dyes. It is also applicable to fabrics containing one or more of the above type dyes and, thus, avoids the necessity of segregating differently dyed fabrics during bleaching.
• the process is suitable for bleaching the fabric in open width or rope form in the widely used continuous bleach J-box ranges with no significant modification of the equipment being required. Although continuous operation is most generally preferred, the method of the invention can be practiced in batch operations when desired.
• EXAMPLE 2 Samples of a light weight, all-cotton fabric containing a one-half inch check pattern dyed with a blue copper phthalocyanine dye were bleached with the bleaching solutions indicated in the following tabulation. White threads were pulled from each bleached sample and the extent of dye bleeding was assessed by observing the relative blue coloration of the white threads. The data tabulated below show that dye bleeding occurred to a significant extent when using the hydrogen peroxide or peracetic acid bleach solutions but did not occur to any significant extent when using the PMS type bleach solutions.
• EXAMPLE 4 This example illustrates bleaching in a continuous op eration. Five samples of various colored fabrics, each about 6 ft. x 10 in., were butt-seamed together and the resulting assembly was butt-seamed into the center of a 100 yd. x 10 in. sample of unbleached, unscoured cotton fabric.
• the colored samples were: (a) a sample of the allcotton fabric used in Example 2, (b) a sample of the cotton/polyester fabric used in Example 2, (c) an all-cotton light-weight fabric having a 1-inch red checked pattern dyed with naphthol red, (d) a medium weight all-cotton fabric having naphthol red stripes and yellow stripes against a broad white background, and (e) an all-cotton seersucker containing alternating A" white and green . ⁇ li5 minutes at 210 F together-. Do;
• the resulting fabric train was continuously saturated to about of its weight with a PMS bleaching solution of the composition set forth in Example 3, then bleached by passing it continuously through a J-box maintained at about 190 F. with a mixture of steam and air.
• the rate of travel of the fabric train through the J-box was such as to give a residence time thereir't: for the fabric of about 30 minutes.
• the bleached fabric withdrawn from the J-box was washed by passing it through water at 180 F. following which the process was repe ted. All of the colored fabric samples in the trainwere well-bleached and showed no evidence of bleeding or mark-off of the dye onto undyed portions of the fabric.
• EXAMPLE 5 This example illustrates bleaching with a peroxymonosulfate solution in accordance with the invention in a batch operation.
• the bleach solution contained 0.2% PMS, 0.5% TSPP and 0.3% acetic acid, and its pH had been adjusted to 6.2 with caustic soda.
• the bleached samples had well-bleached white backgrounds which showed no visible n'ace of dye bleeding or mark-off.
• the fabric bleached in the above example contained many motes, some of which remained after the bleaching operation. This fabric was more difficult to bleach than 'were the fabrics used in the other examples and the fact EXAMPLE 6
• Samples of a cotton-polyester shirt material containing crisscrossing stripes of yarns dyed with either an orange dye, a gray dye or a naphthol red dye were saturated with a bleach solution containing 1% PMS, 2% TSPP, and 0.5 acetic acid, its pH having been adjusted to 6.8 with caustic soda. The saturated samples were then heated at 180 F. for 15 minutes. This bleaching treatment caused 7: dye bleeding or mark-off, nor any visible change in the color or hue of the dye.
• EXAMPLE 7 Liquor: goods Bleach solution ratio Bleach conditions ⁇ l PMS 2.0% sodium acetate trihymzl 150 F./1 hour.
• the preferred peroxymonosulfate bleach solutions for use in practicing the method of the invention are slightly acidic. It might have been expected that such acidic solutions would have a degrading effect upon cellulosic fabrics. It has been found, however, that no significant degradation of such fabrics occurs when they are bleached with the PMS solutions indicated in the examples under the preferred pH conditions, i.e., pH 5.5 to 7. Thus, cotton fabrics bleached in single-stage operations under those conditions gave cuam values no higher than about 3. These are highly acceptable values since a cuam fluidity not exceeding about 7 is generally considered satisfactory.
• a method of bleaching a textile fabric having por' tions thereof dyed with a sensitive dyestufi comprising subjecting said fabric to the action of an aqueous bleaching solution consisting essentially of a water-soluble peroxymonosulfate at a concentration to provide from 0.005 to 1% active oxygen and a buffering agent etiective to maintain the pH of the solution within the pH range of 5 to 8.5.
• bleaching is effected by immersing the fabric in the bleaching solution at a temperature up to about 212 R, which solution contains 0.005 to 0.02% active oxygen.
• bleaching is effected by saturating the fabric with the bleaching solution containing 0.03 to 0.2% active oxygen, and maintaining the saturated fabric at a temperature from F. to about 212 Fffor from about 10 minutes to 5 hours.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Inorganic Chemistry (AREA)
• Coloring (AREA)
• Detergent Compositions (AREA)

Applications Claiming Priority (1)

Publications (1)

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Family Applications (1)

Country Status (6)

Cited By (3)

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• 0
  • NL NL136358D patent/NL136358C/xx active
• 1967
  • 1967-12-20 US US691970A patent/US3556710A/en not_active Expired - Lifetime
• 1968
  • 1968-12-17 DE DE19681815171 patent/DE1815171A1/de active Pending
  • 1968-12-19 FR FR1598534D patent/FR1598534A/fr not_active Expired
  • 1968-12-19 BE BE725712D patent/BE725712A/xx unknown
  • 1968-12-20 GB GB60813/68A patent/GB1243549A/en not_active Expired
  • 1968-12-20 NL NL6818436A patent/NL6818436A/xx unknown

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