METHOD OF DECOLORIZING FABRICS

Abstract

A method for localized or diffused decolorization of colored fabrics and garments by applying an accelerating substance comprising quaternary ammonium salts and subsequently treating with ozone.

Claims

1-11. (canceled)

12. A method for decolorizing a textile product comprising: (a) pre-treatment, by applying an accelerating substance comprising quaternary ammonium salts to at least a portion of said textile product; and thereafter (c) ozonation, by introducing and maintaining said textile product in an ozonating fluid.

13. The method of claim 12, wherein the textile product comprises denim-type coloured cotton.

14. The method of claim 13, wherein the accelerating substance comprises a solution of quaternary ammonium salts with a concentration between 1% and 30%.

15. The method of claim 14, wherein the accelerating substance comprises a solution of quaternary ammonium salts with a concentration of 3%.

16. The method of claim 13, wherein the quaternary ammonium salts comprise cetrimonium chloride.

17. The method of claim 13, wherein the quaternary ammonium salts comprise benzalkonium chloride.

18. The method of claim 12, further comprising (b) first drying of said textile product following (a) pre-treatment but prior to (c) ozonation.

19. The method of claim 18, further comprising (d) neutralization of any residual ozone remaining on the textile product following (c) ozonation, wherein (d) neutralization comprises application of a reducing compound in a bath or by subsequent rinses which is followed by a second drying step.

20. The method of claim 19, wherein (a) pre-treatment comprises selective local application of the accelerating substance on one or more circumscribed areas of the textile product.

21. The method of claim 19, wherein during (a) pre-treatment the accelerating substance is applied diffusely on the textile product by means of an aqueous bath, by nebulization or by contact with a plurality of pre-cut soaked rags.

22. The method of claim 12, further comprising (d) neutralization of any residual ozone remaining on the textile product following (c) ozonation, wherein (d) neutralization comprises application of a reducing compound in a bath or by subsequent rinses which is followed by a second drying step.

23. The method of claim 12, wherein (a) pre-treatment comprises selective local application of the accelerating substance on one or more circumscribed areas of the textile product.

24. The method of claim 23, wherein (a) pre-treatment further comprises manual application of the accelerating substance using a brush or a soaked glove or by nebulizing it with an airbrush.

25. The method of claim 12, wherein during (a) pre-treatment the accelerating substance is applied diffusely on the textile product by means of an aqueous bath, by nebulization or by contact with a plurality of pre-cut soaked rags.

26. The method of claim 12, wherein the accelerating substance comprises a solution of quaternary ammonium salts with a concentration between 1% and 30%.

27. The method of claim 26, wherein the accelerating substance comprises a solution of quaternary ammonium salts with a concentration of 3%.

28. The method of claim 12, wherein the quaternary ammonium salts comprise cetrimonium chloride.

29. The method of claim 12, wherein the quaternary ammonium salts comprise benzalkonium chloride.

30. The method of claim 12, wherein the accelerating substance comprises at least one adjuvant compound, wherein the at least one adjuvant compound facilitates application of the accelerating substance on the textile product.

31. The method of claim 30, wherein the at least one adjuvant compound comprises a surfactant or a pH-buffering substance.

Description

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

[0043] In the present patent text, the term “ozonization” refers to a process of treatment with ozone that consists in placing the textile product inside a fluid enriched with ozone. In the textile industry sector, the ozonization process is carried out by putting the textile product to be treated inside a hermetic machine, similar to an industrial washing machine, inside which the ozone produced by an ozone generator is introduced. The ozonization process can take place in dry conditions, that is without using water, by pumping the ozone gas inside the machine or, alternatively, by immersing the textile product in an aqueous bath in which the ozone is dissolved.

[0044] The method object of the present invention essentially comprises the following main phases: [0045] (a) Pre-treatment: in this first pre-treatment step, the textile product is wetted at least partially with an accelerating substance comprising quaternary ammonium salts, preferably cetrimonium chloride and/or benzalkonium chloride; [0046] (c) Ozonization: in this phase, the pre-treated product is placed inside an ozone machine of a known type and kept there for a certain period of time immersed in an atmosphere rich in this gas.

[0047] After the pre-treatment phase (a) but before the ozonation phase (c), the following intermediate phase may optionally be performed: [0048] (b) Drying: in this phase the textile product is dried according to known processes, in order to eliminate the humidity that could affect the next phase of the treatment with ozone.

[0049] Finally, in certain versions of the method, after the ozonization phase (c) an additional step is performed: [0050] (d) Neutralization: in this phase, the residual ozone is neutralized by means of a known reducing product applied in the bath or by a series of successive rinses of the product, followed by further drying.

[0051] During the ozonization phase (c), the oxidizing action of the ozone combined with the accelerating substance composed of ammonium salts, applied in the previous pre-treatment phase (a), causes a decolorization of the fabric. In other words, the ammonium salt compound accentuates the bleaching action of the ozone in the areas of the fabric on which it has been applied.

[0052] The method disclosed in the present invention can be used to achieve localized decolorization of the textile product or diffuse decolorization. In the first case, the areas where the accelerant has been applied visibly exhibit more pronounced discoloration than the areas where the accelerant has not been applied. If the pre-treatment is applied diffusely over the entire textile product, a substantially uniform bleaching is obtained but more pronounced than if ozone alone were used.

[0053] Preferably the accelerating substance employed is a cetrimonium chloride solution. The percentage concentration by weight of solute is preferably between 1% and 30% although solutions with lower or higher concentrations of solute may be employed; excellent results are obtained with a 3% concentration.

[0054] In lieu of cetrimonium chloride, a solution of benzalkonium chloride or alternatively a mixture of the above compounds of quaternary ammonium salts or other quaternary ammonium salts may be used.

[0055] In some versions of the invention, said accelerating substance further comprises at least one adjuvant compound, such as a surfactant or pH buffering substance or other similar substance, useful to facilitate application to the textile product.

[0056] According to a possible version of the invention, aimed at obtaining a localized decolorization or bleaching only in some specific areas of the textile product, during the pre-treatment step (a) the quaternary ammonium salts compound is applied by an operator directly on one or more circumscribed surface areas of the textile product so that these areas, and only these areas, are soaked with said compound. In this case, the operator applies the mixture directly to the fabric using a brush or a soaked glove, or by spraying it through an airbrush, or more generally by any other method that selectively wets one or more circumscribed areas of the product in a desired manner or pattern.

[0057] In a second version of the method, during the pre-treatment phase (a) the accelerating solution is applied in a diffused way on the textile product, thus obtaining a non-localized discoloring effect, extended to the whole surface of the textile product.

[0058] The diffused application of the accelerant according to this second version of the method object of the invention, can be carried out for example by placing the textile product in an aqueous bath inside a washing machine, in whose washing liquid the same accelerant substance is dissolved.

[0059] Other alternative solutions can be used, such as the nebulization of the accelerating substance inside the drum of a washing machine by means of nozzles incorporated in the machine itself, into which the product to be treated is placed; in this case the treatment cycle does not include an aqueous bath.

[0060] Another technique that can be used to obtain a diffused surface decolorization, although with spots of greater accumulation, is that of the soaked rags. These rags, pre-cut to size, are soaked with the accelerating substance, then, after a light extraction, are put to spin together with the textile product inside a washing machine (without water bath), releasing traces of accelerating substance by contact on the surface of the product.

[0061] It should be pointed out that although reference is made in the description to a textile product, the method object of the invention can be similarly applied to a plurality of textile products which are subjected to the pre-treatment (a) simultaneously or separately and which are subsequently simultaneously subjected to the ozonation (c) and optionally, depending on the versions of the method, to the other treatments of drying (b) and neutralization (d).