Textile Mill Desizing and Scouring: Chemical Selection Guide

Preparation processes—desizing and scouring—determine the success of all subsequent textile finishing operations. Inadequate preparation leads to unlevel dyeing, poor fastness, and rejected fabric. This guide covers textile desizing scouring chemicals selection and application for efficient, effective preparation.

Understanding Preparation Chemistry

The Preparation Sequence

| Stage | Purpose | Target Removal | Next Step Requirement |
|——-|———|—————-|———————-|
| Desizing | Remove sizing agents | Starch, PVA, CMC | Clean for scouring |
| Scouring | Remove natural impurities | Waxes, pectins, oils | Absorbent for dyeing |
| Bleaching | Remove color bodies | Pigments, lignin | White for dyeing |

Sizing Agents and Desizing Chemistry

| Sizing Type | Detection | Desizing Agent | Mechanism |
|————-|———–|—————-|———–|
| Starch | Iodine test (blue) | Amylase enzyme | Hydrolysis |
| Modified starch | Iodine test (purple) | Amylase enzyme | Hydrolysis |
| PVA (polyvinyl alcohol) | Boric acid/iodine | Hot water, oxidizing | Solubilization |
| CMC | Visual/wet-out test | Alkaline wash | Solubilization |
| Acrylic | Chemical test | Alkaline wash | Hydrolysis |
| Mixed/unknown | Multiple tests | Combination | Multiple approach |

Scouring Chemistry

| Impurity | Source | Removal Mechanism | Primary Agent |
|———-|——–|——————-|—————|
| Waxes | Cotton cuticle | Saponification, solubilization | Alkali + surfactant |
| Pectins | Cell walls | Solubilization | Alkali |
| Fats | Seed fragments | Saponification | Alkali + surfactant |
| Proteins | Seed fragments | Hydrolysis | Alkali |
| Mineral matter | Fiber, water | Chelation, solubilization | Sequestrants |

Clissal TextilePro Preparation Range

Product Specifications and Usage

| Product | Function | Active Components | pH (working) | Temperature Range |
|———|———-|——————-|————–|——————-|
| TextilePro Amylase | Starch desizing | Alpha-amylase enzyme | 5.5-7.5 | 60-90°C |
| TextilePro Desize Plus | Combined desizing | Amylase + surfactant | 6.0-8.0 | 60-85°C |
| TextilePro Scour | Scouring | Surfactant + sequestrant | 10-12 | 80-100°C |
| TextilePro Alkali Boost | Scouring booster | NaOH + sequestrant | 13-14 | 80-100°C |
| TextilePro Wetting | Wetting agent | Surfactant blend | 6-11 | 20-100°C |
| TextilePro PWS | Pre-wash starch removal | Surfactant + solvent | 7-10 | 40-60°C |

Dilution and Application Guide

TextilePro Amylase:

| Process Type | Dosage | Temperature | Time | pH |
|————–|——–|————-|——|—–|
| Exhaust (jigger/jet) | 3-5 g/L | 60-70°C | 30-60 min | 6.0-7.0 |
| Pad-batch | 8-12 g/L | Pad cold, batch 60°C | 8-12 hours | 6.0-7.0 |
| Continuous (pad-steam) | 10-15 g/L | Pad warm, steam 100°C | 2-5 min | 6.0-7.0 |
| Hot water setting | 2-4 g/L | 85-90°C | 15-30 min | 6.0-7.5 |

TextilePro Scour:

| Process Type | Dosage | NaOH Addition | Temperature | Time |
|————–|——–|—————|————-|——|
| Light scour | 3-5 g/L | 5-10 g/L | 80-90°C | 30-45 min |
| Standard scour | 5-8 g/L | 15-25 g/L | 90-100°C | 45-60 min |
| Heavy scour | 8-12 g/L | 25-40 g/L | 95-100°C | 60-90 min |
| Combined desize-scour | 6-10 g/L | 20-30 g/L | 90-95°C | 60 min |

Process Recipes

Enzymatic Desizing (Exhaust)

Standard recipe for 100% cotton, starch-sized:

| Component | Dosage | Function |
|———–|——–|———-|
| Water | L:R 1:10-1:15 | Bath |
| TextilePro Amylase | 4 g/L | Enzyme |
| TextilePro Wetting | 1-2 g/L | Penetration |
| Common salt | 5-10 g/L | Enzyme activator |
| pH adjustment | If needed, pH 6.0-7.0 | Optimal enzyme activity |

Procedure:

1. Fill machine, heat to 40°C
2. Add wetting agent, run 2 min
3. Load fabric
4. Add salt, then enzyme
5. Raise temperature to 65-70°C (15-20 min)
6. Hold at temperature 30-45 min
7. Drop bath, hot rinse 80°C
8. Cold rinse
9. Verify: Iodine test (should be minimal blue/no reaction)

Combined Desizing-Scouring

One-step process for efficiency:

| Component | Dosage | Function |
|———–|——–|———-|
| Water | L:R 1:8-1:10 | Bath |
| TextilePro Scour | 8 g/L | Surfactant/sequestrant |
| TextilePro Alkali Boost | 25 g/L | Alkali system |
| TextilePro Amylase | 3 g/L | Enzyme (active at start) |
| Hydrogen peroxide (50%) | 15 ml/L | Oxidative desizing assist |

Procedure:

1. Fill, load fabric
2. Add TextilePro Scour, Amylase
3. Raise to 60°C, hold 15 min (enzyme phase)
4. Add TextilePro Alkali Boost
5. Add hydrogen peroxide slowly
6. Raise to 95°C
7. Hold at 95°C for 45-60 min
8. Drop bath, hot rinse × 2
9. Cold rinse
10. Verify: Absorbency test, iodine test

Continuous Range Preparation

Pad-steam process:

| Position | Chemical | Concentration | Temperature |
|———-|———-|—————|————-|
| Saturator (desize) | TextilePro Amylase + Wetting | 12 g/L + 3 g/L | 50-60°C |
| Steamer 1 | Steam | – | 100°C, 2-3 min |
| Wash boxes 1-2 | Hot water | – | 90-95°C |
| Saturator (scour) | TextilePro Scour + NaOH | 15 g/L + 40 g/L | 80°C |
| Steamer 2 | Steam | – | 100°C, 3-5 min |
| Wash boxes 3-6 | Hot/warm/cold sequence | – | Progressive cooling |

Quality Verification

Desizing Verification

Iodine Test:

| Result | Interpretation | Action |
|——–|—————-|——–|
| Deep blue | Heavy starch remaining | Repeat desizing |
| Purple/violet | Moderate starch | Extended rinse or repeat |
| Light brown/tan | Minimal starch | Acceptable |
| No color change | Starch removed | Good for scouring |

Tegewa Scale:

| Rating | Starch Level | Acceptance |
|——–|————–|————|
| 1-3 | Heavy starch | Reject |
| 4-5 | Moderate starch | Marginally acceptable |
| 6-7 | Light starch | Acceptable |
| 8-9 | Minimal/no starch | Good |

Scouring Verification

Absorbency/Wicking Test:

| Result | Interpretation | Action |
|——–|—————-|——–|
| Water beads/runs off | Poor scouring | Repeat scouring |
| Slow absorption (>5 sec) | Moderate scouring | May need improvement |
| Immediate absorption (<5 sec) | Good scouring | Proceed | | Instant absorption + wicking | Excellent scouring | Ideal |Weight Loss:

| Fabric Type | Expected Weight Loss | Interpretation |
|————-|———————|—————-|
| Greige cotton | 5-10% | Normal scour |
| Combed cotton | 4-8% | Normal scour |
| Blends (cotton/poly) | 2-5% | Reduced (less cotton impurity) |

Troubleshooting

Problem: Incomplete Desizing

Symptoms: Blue/purple iodine test, uneven dyeing

Possible causes:

| Cause | Diagnosis | Solution |
|——-|———–|———-|
| Low enzyme dosage | Check concentration | Increase dosage |
| Wrong pH | pH meter check | Adjust to 6.0-7.0 |
| Temperature too low | Thermometer check | Ensure 60-70°C |
| Insufficient time | Timer check | Extend to 45-60 min |
| Enzyme inactivated by alkali | Process sequence check | Add enzyme before alkali |
| Heavy sizing | Client inquiry | Increase dosage + time |

Problem: Poor Absorbency After Scouring

Symptoms: Water beading, uneven dye uptake

Possible causes:

| Cause | Diagnosis | Solution |
|——-|———–|———-|
| Low alkali | pH check | Increase NaOH |
| Low temperature | Thermometer | Achieve 95-100°C |
| Insufficient time | Timer | Extend treatment |
| Low surfactant | Process check | Increase TextilePro Scour |
| Inadequate desizing | Iodine test | Repeat desize first |
| High hardness water | Water test | Add sequestrant |

Problem: Fabric Damage

Symptoms: Tender fabric, holes, strength loss

Possible causes:

| Cause | Diagnosis | Solution |
|——-|———–|———-|
| Excessive alkali | Check NaOH dosage | Reduce alkali |
| Excessive temperature | Temperature logs | Reduce temperature |
| Excessive time | Process records | Shorten treatment |
| Peroxide without stabilizer | Process recipe | Add stabilizer |
| Contamination (metal, etc.) | Source investigation | Water treatment |

Economic Optimization

Cost Per Meter Calculation

| Cost Element | Standard Process | Optimized Process |
|————–|—————–|——————-|
| Enzyme (Amylase) | ₹0.40/m | ₹0.35/m |
| Surfactant/Scour | ₹0.30/m | ₹0.25/m |
| Alkali (NaOH) | ₹0.15/m | ₹0.12/m |
| Sequestrant | ₹0.08/m | ₹0.06/m |
| Wetting agent | ₹0.05/m | ₹0.04/m |
| Water | ₹0.20/m | ₹0.15/m |
| Steam/Energy | ₹0.50/m | ₹0.40/m |
| Total | ₹1.68/m | ₹1.37/m |

Optimization savings: ~18% per meter

Clissal Ultra Concentrate Value

| Product Format | Product Cost | Storage | Handling |
|—————-|————–|———|———-|
| Standard grade | ₹120/kg | 100% | Standard |
| Clissal TextilePro (5x) | ₹100/kg effective | 20% | Reduced |

Sustainability Considerations

Water Consumption Reduction

| Approach | Water Savings | Implementation |
|———-|—————|—————-|
| Combined desize-scour | 30-40% | Single bath process |
| Counter-current washing | 20-30% | Equipment modification |
| Optimized bath ratios | 15-25% | Process adjustment |
| Water recycling | 40-60% | Treatment investment |

Chemical Efficiency

| Strategy | Reduction | Approach |
|———-|———–|———-|
| Right-sizing dosages | 10-20% | Process optimization |
| Ultra-concentrates | 15-25% | Product change |
| Combined products | 10-15% | Fewer additions |
| Recovery systems | 20-40% | Alkali recovery |

Clissal Textile Mill Support

Technical Services

| Service | Description | Frequency |
|———|————-|———–|
| Process audit | Review current preparation | Quarterly |
| Recipe optimization | Customized formulations | As needed |
| Troubleshooting | Problem resolution | On-call |
| Training | Staff development | Annual |
| Lab testing | Fabric analysis | As needed |

Ordering Information

| Product | Pack Sizes | Shelf Life |
|———|————|————|
| TextilePro Amylase | 25kg, 50kg drums | 12 months |
| TextilePro Desize Plus | 25kg, 50kg drums | 12 months |
| TextilePro Scour | 25kg, 200kg drums | 18 months |
| TextilePro Alkali Boost | 25kg, 200kg drums | 24 months |
| TextilePro Wetting | 25kg, 200kg drums | 18 months |

Conclusion: Foundation for Finishing Excellence

Desizing and scouring set the stage for all subsequent textile finishing. Poor preparation cannot be compensated by excellent dyeing—the foundation must be right. Proper chemical selection, precise application, and rigorous verification ensure fabrics are truly prepared for dyeing and finishing.

Clissal TextilePro products are specifically formulated for Indian textile mill conditions, with the technical support and optimization assistance that help mills achieve consistent, efficient preparation processes.

Need preparation process optimization? Contact Clissal for a technical audit and customized recommendations.

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About Clissal: A brand of Jaivin Surfactants, Clissal serves textile mills across India with specialized wet processing chemistry. Our textile team combines formulation expertise with practical mill experience.