Dasteck ChemicalsYantai Dasteck Chemicals Co., Ltd.
Direct answer
For lace, mesh, chiffon and similar light or open-structured fabrics, the main risk in reduction clearing is not incomplete cleaning but distortion, snagging, holes and curled edges. Thiourea dioxide is milder than hydrosulfite, but the recipe still has to be set separately for light fabrics: less mechanical action, a lower temperature ceiling and a shorter time.
1. Three differences from standard fabrics
| Item | Standard knit or woven | Light and mesh fabrics |
|---|---|---|
| Structural strength | Relatively high | Low; snags easily and can unravel |
| Sensitivity to mechanical action | Moderate | High; both drum and jet action cause damage |
| Sensitivity to temperature | Moderate | Heat distorts, creases and curls the edges |
2. A conservative starting point
| Parameter | Starting value | Note |
|---|---|---|
| Thiourea dioxide | about one third of the hydrosulfite dose | Convert first, then confirm on a trial |
| Caustic soda | the lower end of the normal range | Excess alkali increases swelling and distortion |
| Temperature | 60 to 75 C | Lower than a standard reduction clear |
| Time | 10 to 20 min | Better short than long; split into batches if needed |
| Liquor ratio and load | Larger liquor ratio, smaller load | Reduces friction and compression between pieces |
3. Four operating points
1. Reduce mechanical action: prefer airflow or low-tension machinery, and lower the speed
2. Do not fill the machine: an overloaded machine sharply increases snagging and chafing
3. Heat and cool slowly: rapid temperature changes cause creasing and curled edges
4. Set or open-width handle immediately after unloading, and keep wet storage time short
4. Two things not to do
Sources
Starting values are the recommended ranges from our technical data sheet and published literature. Light fabrics vary widely, so confirm on a bench sample of your own greige.