In 2010 I used a fabric dyed with CO2 instead of water for the project no H2O. (click here) Now it is not only possible to dye with CO2, but also to remove dye from a fabric, which gives great options in the recycling process of textiles. A few companies are busy with this new removal technique. For example Dutch company Feyecon. They are a partner in the joint venture company DyeCoo, a company that dyes fabric with CO2. And now they are able to strip colour from dyed polyester textiles with liquid (super-critical) CO2. |
This technique is actually a reverse of the CO2 dyeing technique. The textile is on a cylinder inside the machine. The CO2 is pumped into the machine. The pressure is raised to around 250 bar, the CO2 liquidised and releases the dye of the textile through circulation. After colour removal the system is depressurised, after which the CO2 turns back into gas and the fabric dries. No addition of extra chemicals such as dispersion agents, salts etc is needed. The remaining dye is collected after each cycle and this way it will not end up in the environment. Feyecon even claimed that the dye can also be recycled and is now investigating if it is possible to remove finishing chemicals and auxiliaries from fabrics as well.
In addition to removing dye from fabrics, CO2 is also used to clean laundry from stains by the company CO2Nexus. (http://www.tersussolutions.com/solutions/)
Another company that removes stuff from fabrics is the taiwan textile producer Pepwing. They have developed a new plasma technology named New Airtek by Plasma that enables them to remove all added finishings and coatings from a textile such as water repellents. The removed chemicals are recovered and disposed responsibly. [1]
When textiles can be “bleached” in these environment friendly ways the recycling process from textile to fibre to new thread into new textile will become easier as all textiles can be uncoloured and recoloured in the desired colour of that moment. Currently a sorting process is used in which textiles are sorted per colour and material content prior to shredding and spinning of new thread. In the future only sorting on material content (cotton, polyester) is needed after which the fabric can be uncoloured and recoloured.
Another company that removes stuff from fabrics is the taiwan textile producer Pepwing. They have developed a new plasma technology named New Airtek by Plasma that enables them to remove all added finishings and coatings from a textile such as water repellents. The removed chemicals are recovered and disposed responsibly. [1]
When textiles can be “bleached” in these environment friendly ways the recycling process from textile to fibre to new thread into new textile will become easier as all textiles can be uncoloured and recoloured in the desired colour of that moment. Currently a sorting process is used in which textiles are sorted per colour and material content prior to shredding and spinning of new thread. In the future only sorting on material content (cotton, polyester) is needed after which the fabric can be uncoloured and recoloured.
[1] Plasma fabric recovery from Taiwan, Ecotextile, published 20 February 2014