A leuco dye pastel marking device for use with a substrate treated with an activator of the leuco dye, such that drawing upon the substrate will reveal a color, but drawing on a normal surface will have no visible effect. A solvent such as dimethyl adipate is used to store the leuco dye in a longer-lived, more stable, solid form, and varying hardnesses and consistencies may be achieved by the addition of 12 hydroxystearic acid and ethyl cellulose. The substrate may be treated selectively with the activator such that a texture, image, or hidden message is revealed by the application of the leuco dye pastel to the substrate. One or more substrates and one or more leuco dye pastel marking devices may be presented to a child as a coloring book with pastels that only visibly mark the coloring book and no other surface.

Aqueous leucoindigo solution comprising an aromatic amine in the form of aniline or aniline and N-methylaniline, wherein said leucoindigo is in the form of an alkali metal salt;

wherein the concentration of the aromatic amine is below 40 ppm determined according to ISO 14362-1:2017(E); and
wherein the concentration of the leucoindigo salt is in a concentration range of from 15 to 45% by weight based on the total weight of the solution, and wherein the solution is stable at a temperature of 23 C.; or
wherein the concentration of the leucoindigo salt is in a concentration range of from 45 to 65% by weight based on the total weight of the solution, and wherein the solution is stable at a temperature of 60 C.

Processes are disclosed which substantially eliminate the formation of oxidized indigo dye before and during dye application onto a natural fiber yarn or fabric while allowing the leuco-indigo dye molecule to diffuse fully into the natural fibers of the yarn where it can fix to the fibers prior to oxidation (i.e., exposure of the leuco-dyed yarns to oxygen). Indigo dyed textile products (e.g., dyed cotton yarns that may be twill woven to form a denim fabric) exhibit exceptionally high colorfastness as determined by the AATCC Crock Test.

Processes and apparatus are disclosed which substantially eliminate the formation of oxidized indigo dye before and during dye application onto a natural fiber yarn or fabric while allowing the leuco-indigo dye molecule to diffuse fully into the natural fibers of the yarn where it can fix to the fibers prior to oxidation (i.e., exposure of the leuco-dyed yarns to oxygen). Indigo dyed textile products (e.g., dyed cotton yarns that may be twill woven to form a denim fabric) exhibit exceptionally high colorfastness as determined by the AATCC Crock Test.

A method for dyeing a modacrylic/cellulosic fabric includes the steps of providing a fabric comprising modacrylic fibers and cellulosic fibers. An aqueous vat dye composition comprising water and a vat dye is applied to the fabric to provide a vat dyed modacrylic/cellulosic fabric. The vat dyed modacrylic/cellulosic fabric is dried. The vat dyed modacrylic/cellulosic fabric is then contacted with a reducing agent. The vat dyed modacrylic/cellulosic fabric is then steamed to promote dye penetration into the fibers. The vat dyed modacrylic/cellulosic fabric is then washed in a first wash step with a wash composition comprising water to remove excess vat dye and reducing agent. The vat dyed modacrylic/cellulosic fabric is contacted with an oxidation oxidizing agent. The vat dyed modacrylic/cellulosic fabric is washed in a second wash step to remove excess oxidation agent.

A method for dyeing a modacrylic/cellulosic fabric includes the steps of providing a fabric comprising modacrylic fibers and cellulosic fibers. An aqueous vat dye composition comprising water and a vat dye is applied to the fabric to provide a vat dyed modacrylic/cellulosic fabric. The vat dyed modacrylic/cellulosic fabric is dried. The vat dyed modacrylic/cellulosic fabric is then contacted with a reducing agent. The vat dyed modacrylic/cellulosic fabric is then steamed to promote dye penetration into the fibers. The vat dyed modacrylic/cellulosic fabric is then washed in a first wash step with a wash composition comprising water to remove excess vat dye and reducing agent. The vat dyed modacrylic/cellulosic fabric is contacted with an oxidation oxidizing agent. The vat dyed modacrylic/cellulosic fabric is washed in a second wash step to remove excess oxidation agent.

Described herein are methods of dyeing fibers, and dyed fibers and textiles made using the methods. The methods involve contacting a fiber with a dye liquor at a dye liquor temperature of about 30 C. to 115 C. to form a dyed fiber, wherein the dye liquor components include at least N,N-diacetyl indigo and a salt solution having ionic strength of about 0.03 M (moles/liter) to 1 M and pH of about 3 to 8 at 20 C. The contacting is generally carried out for a contact period of about 10 seconds to 30 minutes, for example by immersing the fiber in the heated dye liquor. By using the disclosed methods, N,N-diacetyl indigo is substantially uniformly distributed on the dyed fiber to provide intense, vibrant colors affixed thereto. Dyed textiles display substantially uniform color.

The present invention relates generally to compositions and methods for oxidizing or discoloring garments, such as denim. Another aspect relates to providing a cost-effective and environmentally safe alternative to hazardous bleaching agents, such as potassium permanganate.

Processes and apparatus are disclosed which substantially eliminate the formation of oxidized indigo dye before and during dye application onto a natural fiber yarn or fabric while allowing the leuco-indigo dye molecule to diffuse fully into the natural fibers of the yarn where it can fix to the fibers prior to oxidation (i.e., exposure of the leuco-dyed yarns to oxygen). Indigo dyed textile products (e.g., dyed cotton yarns that may be twill woven to form a denim fabric) exhibit exceptionally high colorfastness as determined by the AATCC Crock Test.

A textile is dyed by treating the textile with a composition containing 2D nano and/or microparticles of carbon and by dyeing the textile with a dye that is different from said carbon particles.