Dyeing without water

Textile dying and treatment processes produce 17 to 20 percent of industrial water pollution in the world. 72 toxic chemicals, 30 of which cannot be removed, have been found in our water solely from textile dyeing. As a vital part of textile production, the dyeing processes cause a large problem for designers who are trying to be more environmentally conscious.

 AirDye® technology is a water free dyeing and printing process. AirDye technology has been produced by AirDye Solutions, formerly Colorep Inc., and is a technology development and textile design company. On their website AirDye Solutions describe themselves as, “passionate about creating new printing and dyeing technologies that improve quality, value, and accessibility while helping to sustain the planet.”
AirDye technology uses a one-step process, where the liquid state of dye is eliminated altogether. The process starts with heating fabric and simultaneously dye is injected into the fibers in the form of gas. “The entire process is waste-free: the paper is recycled, and used dyes and toners are also recycled to make tar and asphalt.” One downfall is that only synthetic textiles can be dyed using AirDye, as the physics of the technology do not work with natural fibers such as cotton.
Up to 95% of the water, 86% of the energy and 84% of the green house gases can be saved using AieDye as compared to conventional print and dye methods. Up to 45 gallons of water can be saved in the production of just one garment. The dying of synthetic fabrics alone uses 2.4 trillion gallons of water, every year, and with an unknown/untold amount of environmental damage.
AirDye technology creates a large opportunity for regions around the globe that cannot obtain water as easily, to localize textile production. 
As AirDye technology improves, more water/energy will be saved and hopefully the mass market of textile production could be ready for a monumental change.

AirDye® Technology

Waterless Dyeing of Polyester

DryDye technology

DyeCoo Textile Systems, a Netherlands-based company, created DryDye technology and the first commercially available textile dyeing machines to use recycled carbon dioxide instead of water. The name “DyeCoo” was derived from the process of “dyeing” with “CO2” (carbon dioxide).

DryDye fabrics are dyed using supercritical fluid CO2, which means carbon dioxide is in the form of an expanded liquid or heavily compressed gas. Once the CO2 is heated to 120 degrees Celsius and pressurized, it can then color synthetic fibers and enhances the distribution of dyes into fabrics, as stated on DyeCoo’s website.

Read About Waterless dyeing of polyester using supercritical carbondioxide by cschumacher here

Colorfastness to bleaching:Peroxide

ISO-105-N02-1995
This method is intended for determining the resistance of the colour of textiles of all kinds, and in all forms, to the action of bleaching baths containing peroxide in concentrations commonly used in textile processing. A specimen of the textile in contact with adjacent fabrics is immersed in the bleaching solution, rinsed and dried. The change in color and the staining .

Printing Technology

What is screen printing

Textile printing refers to the production of designs of any kind that could not be made on textile fabrics by normal weaving/knitting techniques. Before the printing process, the cloth should be thoroughly prepared by different wet process namely designing, scouring and bleaching. Printing is mainly done on finished fabrics, curtain clothes, ladies dress materials, bed sheets, bed covers, fabric for children garments, gents shirts etc. to improve its attractiveness, marketability etc.

Screen printing can be done in single colour or in combination of different colours as per end use requirement. Colour combination is an important area by which the appearance of an ordinary fabric can be improved to a maximum extent. It is, therefore, necessary that the quality printing material, chemicals and printing screen should be good so that printed items are fully accepted in the market.

The various steps involved in printing process are

1.preparation of printing paste,

2.printing of fabric,

3.fixation of dye stuff by curing/steaming,

4.washing off,

5.calendering,

6.folding and packing.

It uses a rigid frame to support a porous mesh (screen) which, in turn, supports a stencil (design). Screens containing the designs is placed over the table and the dye paste is pressed over the screen by means of rubber squeezer. The stencil lets dye paste pass through the mesh (print area) and blocks it everywhere else, to produce an image. A variety of mesh/stencil/squeegee combinations provide a wide range of printing capabilities, thus making screen printing one of the most versatile printing processes known. This same versatility appeals to entrepreneurs in a nearly unlimited number of industries; the wide variety of uses makes screen printing that much more attractive.The selection of dyes and gums depends on the construction of basic cloth to be printed and their end use. After printing, the printed clothes are cured or steamed for the fixation of the colour. Later, the printed material is thoroughly washed to remove loose dye stuffs. Then, it is calendered, folded and packed for the delivery.

   
Quality Control and Standards

A quality printed item should have good fastness to washing, rubbing and light. This can be achieved by properly fixing the print on the cloth by curing or steaming. Dyes to be used should be of good quality and capable of giving bright shades. Printing quality is not covered by any specifications.

Screen Printing in General
Applications of screen printing
Silk Screen Printing Instructions
Printing Process Description :- Introduction to Screen Printing
Digital Textile Priniting :- A guide for beginners
Digital Textile Priniting:-Read Article
Digital Textile Priniting:-Emerging Technologies for Digital Textile Printing
Digital Textile Printing:- An Articles Library