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CN-115142254-B - Method for decolorizing textiles

CN115142254BCN 115142254 BCN115142254 BCN 115142254BCN-115142254-B

Abstract

The present invention relates to a method for decolorizing textiles. The present invention relates to a method for decolorizing a textile, characterized in that the method comprises the steps of (a) pre-treating by applying a promoting substance comprising a quaternary ammonium salt to at least a portion of the textile, and (c) ozonation by introducing and maintaining the textile in an ozonated fluid.

Inventors

  • MATTEO ALFONSO URBINI

Assignees

  • 索科化学有限公司

Dates

Publication Date
20260505
Application Date
20220328
Priority Date
20210329

Claims (12)

  1. 1. A method for decolorizing a textile, the method comprising the steps of: (a) Pretreatment by applying a facilitating substance comprising a quaternary ammonium salt to at least a portion of the textile; (c) Ozonation is performed by introducing and maintaining the textile in an ozonated fluid under dry conditions.
  2. 2. The method according to claim 1, characterized in that it is applied to textiles comprising tannic colored cotton.
  3. 3. The method of claim 1, comprising a drying step (b) of the textile between the pre-treatment step (a) and the ozonation step (c).
  4. 4. The method according to claim 1, characterized in that the ozonation step (c) is followed by a step (d) of neutralization of residual ozone on the textile, said step (d) being carried out by using a reducing compound applied in a bath or by a subsequent rinsing and then drying step.
  5. 5. The method according to any one of claims 1 to 4, wherein in the pre-treatment step (a) the facilitating substance is selectively applied locally in one or more defined areas of the textile.
  6. 6. The method of claim 5, wherein in the pre-treating step (a), the facilitating substance is applied manually by an operator using a brush or soaked glove, or by atomizing it with a spray gun.
  7. 7. The method according to any one of claims 1 to 4, wherein in the pretreatment step (a) the facilitating substance is applied diffusely on the textile by water bath, by atomization or by contact with a plurality of pre-cut soaked rags.
  8. 8. The method according to any one of claims 1 to 4, wherein the facilitating substance is a quaternary ammonium salt solution having a concentration of 1% to 30%.
  9. 9. The method of claim 8, wherein the facilitating substance is a quaternary ammonium salt solution having a concentration of 3%.
  10. 10. The method of any one of claims 1 to 4, wherein the quaternary ammonium salt comprises cetrimide.
  11. 11. The method of any one of claims 1 to 4, wherein the quaternary ammonium salt comprises benzalkonium chloride.
  12. 12. The method according to any one of claims 1 to 4, wherein the facilitating substance comprises at least one auxiliary compound, which is a surfactant or a pH buffering substance, for facilitating the application to the textile.

Description

Method for decolorizing textiles Technical Field The present invention relates to the field of treatment for decolorizing textiles, in particular, but not limited to, garments made of jean (jeans) or tannin (denim) fabrics. More particularly, the present invention relates to a method of decolorizing or bleaching colored fabrics to impart to such fabrics a wear and aging appearance similar to that which would be obtained after years of use. In particular, the present invention is directed to a method for decolorizing textiles due to the synergistic effect of quaternary ammonium cations and ozone. Background As is well known, different chemical products and treatments are used in the industry and in the home for ageing textiles to give some garments greater appeal and aesthetic value. The ageing effect is caused by the discoloration of the fabric, which may be spread over the whole surface of the garment or may be localized to specific areas of the garment itself, as the case may be. It should be noted that although in the following reference is made to denim or tannin fabrics, i.e. fabrics made of cotton, the method of the invention can be applied to any textile. It should also be noted that, in this context, the term textile refers generally to a fabric or garment. In this patent text, the terms bleaching and decolorizing are used interchangeably and refer to a treatment process that is capable of altering the coloration of textiles, typically by making it lighter and more white. In the textile industry, methods for the local decolorization of jeans of tannins or similar fabrics have been known for a long time, i.e. methods that achieve a particularly limited decolorization for specific areas of the product. Currently, the most common bleaching method employs a potassium permanganate solution, which is sprayed by the operator onto specific areas of the fabric to be treated, in the case of pants, in particular the knee and thigh areas. Potassium permanganate is a strong oxidizing agent that reacts with the color of the fabric, whitening it and highlighting the fraying and aging appearance. However, this solution has the disadvantage of exposing the operator to significant risks of his health and safety in the case of inhalation of aerosols formed during the spraying of potassium permanganate on the fabric. Meanwhile, diffusion-decolorization treatment of denim or tannin textiles is known, which is used to obtain a substantially uniform aging effect over the entire surface of the product, i.e. without distinct uneven areas. In the solutions of the type known at present, the textiles to be treated are placed in industrial washing machines, the washing liquid of which is supplemented with chemical compounds such as potassium permanganate, sodium hypochlorite, hydrogen peroxide, laccase. These solutions for diffusion decolorization of textiles require large amounts of chemical additives to achieve a sufficiently strong decolorization effect. The use of these substances has a high environmental impact and the wash water must be purified to reduce the contaminant content. Other drawbacks of these methods are the large consumption of water during the various washing and rinsing stages. In order to overcome the above problems, a method of bleaching textiles using ozone has been developed a few years ago. Ozone is generated on site using a special machine and introduced into a hermetically sealed washing machine into which the textile to be treated is introduced, which treatment may be performed dry or in water. In the case of denim and tannin fabrics, treatment with ozone provides cleaning of the fabric from indigo redeposition and in some cases also provides mild decolourisation. To enhance the bleaching effect of ozone, the fabric is wetted with water to promote the oxidation of ozone. US patent application US20140068871 describes a process for decolorizing a tannin fabric by wetting it with water and then subjecting it to a second ozone bath. A similar solution is described in japanese patent application JPH04100987 a. International patent application WO 2018065388A1 discloses a method for the topical decolorization of tannins fabrics using ozone after soaking certain areas of the fabric with a hygroscopic substance, i.e. a substance that absorbs moisture. In all the above solutions, water is used to enhance the oxidation of ozone, but the results obtained are not satisfactory. In particular, the decolorization effect is weak or moderate and the fabric cannot be selectively decolorized to obtain a strong color contrast, which is now in great demand in the fashion industry. The above mentioned US application US20140068871 also describes a method for the local decolorization of a fabric by treating it in an ozone bath after spraying water only on certain areas of the fabric. However, this solution also has the same drawbacks as the other known solutions described above, i.e. the decolorization that can be achieved