15. December 2021
Bluesign introduces phase-out plan for toxic solvents in Transfer Printing
BLUESIGN and its system partners constantly strive to improve environmental performance and occupational health & safety at work, as well as consumer safety.
Air emissions and the use of solvents can be a topic of concern in many production processes and have always been in the focus of BLUESIGN and its system partners.
For all production sites using solvents, specific requirements apply which are defined by bluesign® CRITERIA. For these sites, solvent mass balances must be compiled, suitable and effective off-gas treatment systems are indispensable, the workplace atmosphere must be strictly monitored, and the air emissions situation must be checked by regular measurements.
In addition to these general principles, BLUESIGN has initiated, together with its system partners, two further programs to reduce the impact of solvents in textile production.
As a very important measure, BLUESIGN has initiated a program which aims to phase out solvents with carcinogenic, mutagenic and/or reproductive toxic properties (known as CMR solvents), such as N,N-Dimethylformamide and toluene. The project progress report will be communicated in 2023.
The second focus is on the use of methanol in transfer printing, also called sublimation printing.
Transfer printing combines techniques of paper and textile printing. The patterns are first printed on paper with suitable inks, and subsequently transferred onto the textile fabric through the application of heat and pressure.
While transfer printing is comparatively clean at the point of application, hazardous chemicals may be used in the paper printing stage.
Methanol is frequently used as a solvent in this production step. Due to its toxicity (toxic if swallowed, in contact with skin or if inhaled), methanol use and emissions should be minimized.
Therefore bluesign® SYSTEM PARTNER companies performing printing of transfer papers have agreed to reduce methanol emissions, either by switching to solvent-free processing or by a combination of effective off-gas treatment systems and substitution of methanol by ethanol.
Half of the Bluesign system partners have already changed or agreed to change to solvent-free digital printing in the coming months. The remaining partners will switch from methanol to ethanol. The project objectives will be achieved in 2023. These measures will result in a reduction of approximately 700 tons of methanol per year.
As a leader in sustainability and following the Best Available Technique (BAT) concept, bluesign® SYSTEM PARTNER Transfertex Print Solutions, located in Kleinostheim (Germany), has for many years been using ethanol as a solvent, and they have installed a regenerative thermal oxidation system to minimize solvent emissions. Transfertex has also developed a smart system to recycle printing pastes, reducing solid waste to an absolute minimum.
BLUESIGN textile engineer Reinhard Umber comments:
“Our program for transfer printing is a good example of how progress in different technologies can be effectively combined to reduce environmental impact. Depending on the needs of the market, various options can be used to minimize impact. No matter which technology is chosen, phasing out methanol will improve the safety situation in the workplace.”