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Pigments technology and application on textile
Technology

Pigments can be considered as colour material insoluble in water.

In order to create a water dispersions of pigments it is necessary to follow two major steps.
  1. create a dispersion;
  2. milling the dispersion;
In phase 1, pigment raw material are in touch with dispersing agents, stabilizers and water in order to "wet" the surface.

In phase 2, pigment dispersion is treated in a milling unit in order to reduce the pigment agglomerates in a very small part, until the requested particle size is obtained (usually < 1 micron)

Textile application

Water based pigment dispersions are used to colour emulsion for textile printing.
An indicative recipe for this paste is reported here below:

Water up to volume
Thickener 30 g/kg
Ammonia 3 g/kg
Binder 150 g/kg

  • Thickener is used to built up the viscosity of the water. Quantity of thickener may change in relation with the viscosity requirement, type of printing and type/constitution of fabric;
  • Ammonia is necessary to guarantee the stability of the final paste even when it is stored for days;
  • Binder and Fixer are used in order to "fix" pigments on the textile fabric (They create a film which protect pigment from rubbing and washing abrasion);
  • Softeners are used in order to improve the final handle of the printed fabric. These chemicals are widely used on knit more than on woven fabric.

Concerning printing process, pigments can be transferred to the fabric by rotary printing machine or flat bed printing machine. After drying the printed fabric needs to be cured at high temperature (150-160°C) in order to provide a complete crosslinking of Binder and Fixer. Washing is not required.