People concerns towards planet earth care (sustainability, CO2 footprint, recycling economy, etc.) as well as personal care (physical exercise, breathing fresh air, consuming bio food, etc) are increasing. Finally, yet importantly, dressing; means awareness in preventing skin contact with harmful substances like toxic dyes, heavy-metal particles, formaldehyde, pesticides, etc.
The most dominant materiel to which the skin is exposed are definitively cotton fibres and here on the scene comes organic cotton. Nowadays only about 1% of total cotton crop is organic and due to its increasing demand organic cotton price is 50% higher compared to normal cotton. Due to its scarcity and high price, several cases of fake organic cotton were reported in the press.
A number of criterions are prescribed to define and certify organic cotton like GOTS (Global Organic Textile Standard), OCS (Organic Content Standard), ISOT (Indian Standard for Organic Textiles) etc and others to support its growth like OCA (Organic Cotton Accelerator), Cotton for Africa, BCI (Better Cotton Initiative) etc. On the other end, a number of labs emerged that perform cotton screening (distinguish organic from GM – genetically modified).
When processing organic cotton, spinning mills may encounter serious processing challenges caused by cotton stickiness, honeydew. Therefore, cotton stickiness may be perceived by spinners as a deterrent for organic cotton processing. Thus, the increasing demand for organic cotton goes hand-in hand with the increasing interest in the cotton stickiness testing. If “sticky cotton†is not detected in time and properly handled, it can generate excessive maintenance costs in spinning, affect the production and compromise yarn quality.
There are several testing techniques for determining cotton stickiness: chemical, mechanical and thermo-mechanical methods. In the latest findings of the ITMF International Committee on Cotton Testing Methods, in cooperation with CIRAD, Fiber Institute Bremen and ICA Bremen, one important conclusion has been outlined: due to its highest correlation with processing behaviour and yarn quality, only thermo-mechanical methods are recommended (in both production and trade).
In fact, the high variation in stickiness within a sample, as well as within a bale and within a lot, makes the thermo-mechanical method suitably designed for daily massive testing, in a trading context as well as in the spinning mill, thus overcoming the constraints of other methods (chemical and physical).
Among different thermo-mechanical equipment used in the ITMF-ICCTM proficiency testing, the CONTEST-S results were proven to provide the lowest inter laboratory CV% variations. In order to supply a solution to overcome the troublesome effects of cotton stickiness (honeydew/sugar content), Mesdan developed a specific testing method as an integral part of its CONTEST-S (testing only cotton stickiness) and CONTEST-F (to test at once all cotton parameters) equipment.
The stickiness module is distinguished by:
- Fully automatic high-volume testing equipment designed to detect, measure and classify cotton stickiness
- Its unique feature of simulating the carding process like in real spinning conditions provides a reliable evaluation of the effective stickiness (cotton fibres tendency to stick to cotton-processing surfaces),
- Stickiness grade and cotton stickiness risk probability assessment enables spinners to anticipate proper actions (how to process & blend different cotton bales),
- Fast testing (30 sec/sample) designed for massive stickiness classification of bales and lots (>500 tests/shift),
- Testing method for stickiness grading recognised by ITMF – ICCTM.
Mesdan stickiness testing method has received an official and full recognition by the ITMF International Committee on Cotton Testing Methods (ICCTM) in April 2020. The ITMF-ICCTM committee members recognised its usefulness and its benefits for the complete cotton supply chain: it assists spinners to achieve consistent yarn quality standards, it sustains traders and cotton suppliers to monitor season crop, it provides grading for research laboratories and classification institutes.