Method to produce a dye for fabrics starting from textile waste material, method to dye fabrics

1. A method to produce a dye, which is suited to be applied on fabrics, starting from textile waste material, said method comprising the following steps:

an initial step, during which textile waste material is provided, which comprises textile fibers which were previously dyed, wherein the textile fibers are selected from: natural fibers of animal or plant origin, artificial fibers, or mixtures thereof;

an application step comprising applying a reactive substance to the textile fibers to make the textile fibers more fragile, wherein the reactive substance comprises colloidal silicic acid; and

a pulverization step after the application step, during which said textile fibers are pulverized to obtain the dye which is a powder.

2. The method according to claim 1 , wherein the natural fibers are selected among: cellulose fibers, protein fibers, or mixtures thereof.

3. The method according to claim 1 , wherein the application step comprises the step of bringing the textile fibers into contact with a bath comprising a water solution or dispersion of the reactive substance.

4. The method according to claim 3 , further comprising a drying step between the application step and the pulverization step, during which the textile fibers are dried.

5. The method according to claim 1 , further comprising the following steps:

a division step, during which the fibers are divided into groups based on their color; said pulverization step comprising the step of separately pulverizing each group of fibers, so as to obtain powders of different colors starting from each group;

a powder selection step, during which the powders of different colors are selected.

6. The method according to claim 5 , further comprising after the powder selection step a powder mixing step, during which the powders of different colors are mixed in order to give a desired color to the dye.

7. The method according to claim 1 , further comprising after the division step, the following steps:

a fiber selection step, during which at least one preliminarily divided group of fibers is selected, said preliminarily divided group of fibers providing a desired color to the dye, and

a fiber mixing step, during which the fibers belonging to the previously divided and selected groups are mixed according to a quantity proportion providing the desired color to the dye;

after said fiber selection step and said fiber mixing step, said pulverization step takes place, during which the previously selected and mixed fibers are pulverized.

8. The method according to claim 1 , comprising a sieving step, during which the pulverized material is sieved.

9. The method according to claim 1 , wherein at least part of the textile fibers were previously dyed with a synthetic dye.

10. The method according to claim 1 , further comprising a comparison step, during which the powdery dye obtained through said pulverization step is compared with a reference color; if the dye does not comply with the reference color, a correction step takes place, during which other colored powders are added to said dye subjected to the comparison step, until a dye is obtained, which has a color similar to the reference color.

11. The method according to claim 1 , wherein the powder has a mean particle diameter Dv90 ranging from 100-150 micrometers, in accordance with the method ISO standard 13320:2009.