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
  • D06L4/12—Bleaching fibres, filaments, threads, yarns, fabrics, feathers or made-up fibrous goods; Bleaching leather or furs using agents which develop oxygen combined with specific additives

Definitions

• the present invention relates to new bleaching compo- United States Patent sitions "for textile fibres' and more particularly to solid and stable compositions Which, in aqueous solution, give oxidising agents having high activity and which are effective at only slightly raised temperatures.
• organic peracids and their salts have the properties of bleaching vegetable, animal or synthetic textile fibres, but the use thereof in practice is made diflicult. because such materials cannot be satisfactorily and sometimes because of their liquid condition.
• the anhydrides employed in these known processes are simple unsubstituted anhydrides, such as benzoic, phthalic, succinic, maleic, glutaric, acetic, propionic and like anhydrides.
• the use thereof presents various disadvantages, however, particularly when they must be employed for bleaching operations at normal temperatures and at pH values below 10.
• the anhydrides of lower monoacids such as acetic, propionic and butyric acids are liquid at normal temperatures andthus are not suitable for the preparation of solid bleaching compounds ready for use.
• solid anhydrides certain of them, such as the benzoic and phthalic anhydrides, have very low solubility in aqueous media and this limits the peroxidation reaction and gives a heterogeneous character to the bleaching.
• Certain dicarboxylic acid anhydrides have the serious disadvantage of having little reactivity in weakly alkaline medium at the relatively low temperature of 50 to 80 C.; this is the case with tetrahydrophthalic and maleic anhydrides, which only form a small amount of organic per compounds in aqueous medium. In the case of numerous solid anhydrides, the oxygen of the initial per compound is thus not satisfactorily utilized.
• the anhydrides of organic diacids ofiering particular interest are the nitrophthalic anhydrides, preferably 3- nitrophthalic anhydride, and the halophthalic anhydrides, such as 4-chlorophthalic anhydride.
• the substituted anhydrides react with the hydrogen peroxide, even in weakly alkaline medium, in order to form corresponding peracids much more completely than the unsubstituted phthalic anhydride.
• a solid source of active oxygen such as: monohydrated or tetrahydrated perborate, percarbonate, perpyrophosphate, urea peroxyhydrate and in general the mineral or organic peroxyhydrates, as well as the mineral or organic peroxides.
• the active oxygen concentration of the bleaching bath is preferably between 20 and 500 mg. of active oxygen per litre.
• the material to be bleached is treated with a solution adjusted to a pH value between 7 and 11. There are used, per molecule of peroxide, 0.4 to 2 molecules of carboxylic acid anhydride substituted by at least one electrophilic group, preferably 0.8 to 1.5 molecules.
• the bleaching can be carried out at slightly elevated temperatures, for example, in the range from 30 to C. and preferably at about 60 C.
• a sulphur black solution with an optical density equal to 0.6 green filter, thickness 10 mm.
• this solution is buffered to an alkaline pH value by a mixture of sodium carbonate and bicarbonate, or by any other buffering system such as those formed from sodium borate.
• This solution is brought to 60 C. and the per compound and the anhydride are added, separately or mixed before use, and the bleaching bath is kept at 60 C. for 20 minutes.
• the sample is then quickly cooled to normal temperature and its optical density is measured by colorimetry. The result is expressed as a percentage of decoloration, related to a comparison sample not provided with active oxygen and placed under the same operational conditions.
• Example 1 Under the conditions described above, the operation takes place in the absence of organic anhydrides, using sodium borate in its monohydrated form NaBO .H O or tetrahydrated form NaBO .4H O. An average degree of decoloration of 5% is obtained. When the temperature is brought to 92 C., always under the same general conditions, the average degree of decoloration is 40%.
• Example 2 Under the test conditions previously described and at a temperature of 60 C., the action of the unsubstituted anhydrides and that of the substituted dicarboxylic anhydrides are compared, the active oxygen being supplied by monohydrated sodium perborate.
• Example 3 Under the same conditions as in Example 2, a mixture of 3-nitrophthalic and 4-nitrophthalic anhydrides is used, obtained by the mixture of acids resulting from 'a phthalic anhydride nitration by means of :a sulphonitric mixture being transformed into anhydride. For a molar ratio of 1 between the anhydride and the active oxygen, a degree of decoloration of 45% is obtained. For a molar ratio of 1.3, a degree of decoloration of 68% is obtained.
• Example 4 Always under the same conditions, the degree of decoloration obtained is compared, the source of active oxygen being on the one hand monohydrated sodium perborate with 15.7% of active oxygen and on the other hand sodium percarbonate with 11.7% of active oxygen, the anhydride in both cases being a sample of 3-nitrophthalic anhydride (melting point 160-163 C.), the molar ratio between the anhydride and the active oxygen being equal to 1.3.
• a degree of decoloration of 49% is obtained with the perborate and of 53 with the percarbonate.
• a mixture formed of 3.4 parts of monohydrated sodium perborate NaBO .H O and 6.6 parts of nitrophthalic anhydride, having a decolouring power of 40%, measured by the test previously described, did not show either a lowering of its active oxygen content or a loss of decolouring power after having been stored for 2 months under normal conditions, i.e., in a standard package, and at ambient temperature.
• a process for bleaching textile fibers comprising immersion in a bleaching bath containing as a source of active oxygen a peroxygen compound and containing a source of active oxygen, comprising additionally adding to the bleaching bath a phthalic acid anhydride having in its molecule at least one hydrogen atom replaced by an electronegative group.
• a bleaching composition for textile fibers containing as a source of active oxygen a peroxygen compound and a phthalic acid anhydride having in its molecule at least one hydrogen atom replaced by an electronega-tive group.
• a method of bleaching comprising passing textile fibers through a bleaching solution comprising a mixture of a source of active oxygen selected from the group consisting of perborates, percarbonates, perpyrophosphates, peroxyhydrates and peroxides, and a phthalic anhydride acid wherein at least one hydrogen atom in the anhydride molecule is replaced by an electrophilic radical selected from the group consisting of N0 Cl, Br, H and NaSO 16.

Landscapes

• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Detergent Compositions (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

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Country Status (5)

Cited By (6)

• 0
  • BE BE630532D patent/BE630532A/xx unknown
• 1962
  • 1962-04-14 FR FR894538A patent/FR1328962A/fr not_active Expired
• 1963
  • 1963-04-01 US US269765A patent/US3298775A/en not_active Expired - Lifetime
  • 1963-04-04 DE DE19631444001 patent/DE1444001A1/de active Pending
  • 1963-04-09 GB GB14208/63A patent/GB968806A/en not_active Expired

Non-Patent Citations (1)

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