SUBSTITUTES FOR STAIN REMOVAL IN THE TEXTILE INDUSTRY
We are glad to place before you the test results of experiments on substitutes for CTC carried out by Textile Committee's Laboratory at Tirupur under the supervision of GTZ in April 2007. This section depicts the methodology of testing and results of various stain removing agents on different fabrics and a variety of stains so that an alternate to CTC can be selected.
ALTERNATIVE TEST METHODOLOGY
Tests have been carried out considering 8 types of commonly occurring stains. Each type of stain has been prepared in a standardized manner on a selection of 11 different types of fabric to ensure full comparability of results.
The alternatives were tested on simulated and real-life stains for fabrics. Simulated stains were made with dirty knitting oil collected from the cylinder bed of the knitting machine (which is the stubborn oil stain) by needle pricking.
Simulated Tests in the Industry
Simulated stains (old knitting oil on knitted cotton cloth) were removed during this process. In post-staining period after 14 days, 100 stains have been removed again.
Simulated Stain – Sample Preparation
Knitted (single jersey-plain) cotton fabrics of dyed and bleached quality were procured from the garment manufacturers.
The fabric lot was cut into 8" X 8" size samples. For each alternative 200 dyed samples and 200 bleached samples were taken.
A total of 16,000 samples were cut out of which 8,000 were for PIAM and 8,000 were for TCe. Dirty knitting oil (~500ml) was collected from the cylinder bed of the knitting machine which causes the stubborn oil stain.
200 dyed samples and 200 bleached samples were stained with dirty knitting oil by pricking the knitting needle dipped in the dirty oil. 100 samples of each were packed separately marking the due date (two weeks later) on the pack. The remaining 200 samples (consisting of 100 dyed and 100 bleached samples) were kept for de-staining on the following day.
Detergent-based alternatives were diluted 10Xconcentration and the organic solvents were taken without dilution. The average size of the stain was measured in mm2 and the total number of stains was noted.
The initial volume of the stain removing agent was measured in the graduated measuring cylinder. The de-staining was done by first steaming the stain and then scrubbing it with a brush in case of detergent alternatives and in case of solvent it was directly applied using the hand-gun. Finally after de-staining, the cloth was compressor-air-dried.
The total time taken for de-staining of 100 samples was noted with a stop watch (this was the sum total of steaming time plus stain removal time plus air-drying time).
After the de-staining of the 100 samples, the final volume of the alternative was recorded. The volume of de-staining agent and the time were recorded in separate data sheets for dyed and bleached samples. Besides the above data, residual stains, discolouration, fabric damage and operator's response to smell, feel, skin irritation, etc., were also recorded in respective sheets.
Samples for Real-life Stains
Though the de-staining tests with simulated stains are more scientific, the real-life samples might have stains with different sources and conditions. To confirm the effectiveness of the alternatives, the de-staining test on real-life stains were conducted with all the 20 substances. The stain removing exercise was similar to the simulated stain removal with some modifications.
Yellowing Post De-staining
The garments were checked after about a month and noted for yellowing post-de-staining.
Since, among 19 short-listed alternatives only five are non-proprietary; an evaporation test was conducted to analyse the constitution of the proprietary alternatives. The test is described below:
All the detergent alternatives were diluted to 2X concentration and the solvents were taken undiluted. Along with all the alternatives water was also taken as a substance for benchmarking.
Using a dropper three drops (approximately 5 mls) of all the alternatives and water were applied to individual dyed samples.
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The results presented on this page reflect the outcome of tests carried out under controlled laboratory conditions. While all necessary care has been taken during this process, no guaranty can be given that the same results can be reproduced under different conditions. The test methodology is based on a generic procedure which was not optimised for a specific industrial process. Such optimisation may result in
modified outcome. Any trade name or commercial product mentioned here does not constitute an endorsement or recommendation by GTZ
and Textiles Committee.
All fabric samples have been inspected for possible damaging side effects of stain removing agents. No damage or significant loss of fabric strength has been detected. Nevertheless, GTZ
and Textiles Committee decline responsibility for any damages caused by the
application of any of the products listed. It is recommended that products
be tested and evaluated prior to any large scale application.
For some products, particularly solvents, a
toxicity profile has been prepared informing of potential health risks
associated with their usage. The unavailability of such profile does not
indicate the absence of health risks. It is recommended that prior to use of
any substance the Material Safety Data Sheet from the manufacturer be
consulted for potential risks.