What Is the Purpose of Sizing in Textile Manufacturing?

Textile sizing exists for one reason: to help warp yarn survive the stress of weaving.

A warp yarn is subjected to:

• High tension

• Abrasion with healds and reeds

• Repeated bending and friction

• High-speed weft insertion

Without sizing, yarns break frequently, causing loom stoppages, low efficiency, and higher fabric defects.
Well-sized yarns especially those using hydroxylated starch technologies like Alpenol are designed to offer:

• Higher breaking strength

• Lower hairiness

• Better cohesion between fibers

• Uniform stretch under tension

• Reduced shedding and dust

These benefits directly translate into higher loom efficiency and lower weaving costs, which is why sizing is critical for every woven fabric manufacturer.

What Is the Warp Sizing Process in Textiles?

The warp sizing process has two dimensions:

1. The Mechanical Sizing Process (Machine-Side)

This process takes place on a sizing machine—typically a slasher or sectional sizing range.

Steps in Mechanical Sizing

1. Warp beam feeding – Multiple warp beams from warping enter the size bath.

2. Size application (size box) – Yarns pass through a hot slurry where adhesive forms a thin, uniform coating.

3. Squeezing – Squeeze rollers remove excess size and control add-on %.

4. Drying – Yarn passes over drying cylinders at controlled temperature/humidity.

5. Stretching – Controlled stretch gives uniform tension before winding.

6. Re-beaming – All sized threads are wound into a final weaving beam.

Why Alpenol products perform better here

Alpenol’s single-shot and compound agents deliver:

• Higher adhesive power with lower pick-up %

• Uniform film formation

• Better moisture management

• Reduced shedding

• Fewer end breaks at high-speed looms 

These are repeatedly validated in customer mill trials across cotton, viscose, (Polyester-Cotton) PC, (Polyester-Viscose) PV, and specialty high-density programs.

2. The Chemical Sizing Process (Chemical-Side)

The size bath composition determines how the yarn behaves on the loom.

Typical components of a traditional recipe

• Starch / modified starch

• PVA (polyvinyl alcohol)

• CMC (carboxy methyl cellulose)

• Binders & softeners

• Waxes & lubricants

• Preservatives

What modern formulations look like

Alpenol’s chemical technology replaces multi-chemical recipes with:

• Hydroxylated starch-based single-shot products

• No PCP, no restricted substances

• GOTS-approved for organic cotton

• ZDHC Level 3 compliant ingredients

This drastically reduces:

• Complexity

• Environmental load

• Inventory

• Human error

• Effluent COD/BOD during desizing

How Does Sizing Improve Yarn Strength and Weaveability?

Sized yarns show measurable improvements:

Alpenol’s hydroxylated starch molecules penetrate yarn cores more effectively, producing flexible yet strong films ideal for modern looms.

What Types of Sizing Agents Are Used in the Textile Industry?

Traditional Sizing Agents

• Starches (maize, tapioca, potato)

• PVA

• CMC

• Acrylic binders

• Softening oils and waxes

To learn more about the different sizing agents used, click here.

Modern/Advanced Agents (Alpenol examples)

• Alpenol is Single-shot products requiring no extra binders, lubricants or additives

These modern agents offer performance + sustainability without complexity.

What Is the Desizing Process in Textile Manufacturing? (Brief)

Desizing removes the size film from woven fabric before dyeing and finishing.

Common Desizing Methods

• Enzymatic desizing (amylase)

• Oxidative desizing

• Hot wash desizing

To learn more about the desizing process, click here.

Modern sustainable sizes such as those from Alpenol require:

• Lower chemical dosage

• Faster washing-off

• Lower effluent load

• Better whiteness in bleaching
  This is repeatedly validated in mill reports where desizing chemical cost reduces significantly.

How Does Sizing Differ for Cotton vs. Synthetic Yarns?

Alpenol’s product range covers all compositions with specialized versions for open-end, ring, vortex, fine counts, coarse counts, and dyed yarn requirements.

What Are the Challenges and Common Problems in Textile Sizing?

• Excess size pick-up

• Inconsistent viscosity

• Improper penetration

• Yarn sticking

• Beam softening/drying out

• High hairiness post drying

• Excessive dust & fly

• High end breaks on loom

• Desizing difficulty

• High BOD/COD effluent load

Modern single-shot products (Alpenol) minimize these issues due to consistent chemistry and optimized cooking behavior.

What Is the Environmental Impact of Sizing Chemicals?

Traditional sizing using PVA, synthetic binders, and waxes leads to:

• High BOD/COD in wastewater

• Microplastic-like residues

• Large water consumption

• High energy drying load

How Alpenol reduces environmental impact

• ZDHC Level 3 compliant

• GOTS approved for organic cotton

• OEKO-TEX Eco Passport certified

• Starch-based chemistry (biodegradable)

• Reduced pick-up → reduced drying energy

• Easy desizing → lower chemical use

• No PCP or other restricted substances

What Are the Benefits of Modern Sizing Technologies in Weaving?

Key Benefits

• Higher loom efficiency (5–10% improvement commonly reported)

• Lower warp breaks even at low humidity

• Higher production at high insertion speeds (up to 1200 picks/min)

• Improved fabric appearance

• Lower dead-loss (down to 15–20%)

• Lower energy cost (up to 20% reduction)

• Better export-grade packing due to reduced defects

Modern sizing is not just a chemical—it’s a cost-saving and quality-improving strategy.

What Are the Quality Control Parameters in Sizing?

QC Parameters to Check

• Size viscosity

• pH

• Temperature in size box

• Pick-up %

• Moisture of sized yarn

• Stretch %

• Film strength & flexibility

• Beam density & uniformity

• End breakage rate

• Size penetration depth

Alpenol’s cooking instructions provided in product TDS and the technical service provided ensures consistent slurry quality and reproducible performance.

What Are the Alternatives to Traditional Textile Sizing?

• Foam sizing

• Solvent or low-liquor sizing

• Synthetic binder-free formulations (Alpenol, siZaltex LVn)

• Biodegradable size systems (Alpenol, siZaltex LVn)

• Single-shot sizing compounds 

• Slurry-less cold-soluble preparations 

These alternatives reduce water, steam, and chemical load significantly.

Frequently Asked Questions (FAQs)

1. What exactly does sizing do to yarn?

Sizing forms a thin, protective film over warp yarns to enhance strength, cohesion and abrasion resistance, ensuring smoother and faster weaving.

2. Is sizing necessary for all woven fabrics?

Yes. Almost every woven fabric requires sizing except very coarse or specially engineered yarns. Fine, dyed, viscose, PC and high-density fabrics benefit the most.

3. Does sizing impact dyeing quality?

Yes. Proper sizing and easy desizing (as seen in Alpenol products) improves fabric whiteness, dye uniformity, and reduces processing chemicals.

4. How much size add-on is ideal?

Typically 5–12% depending on yarn count and fiber. Modern single-shot agents require lower add-on for higher performance.

5. Which sizing agent is best for PC or PV blends?

Compounds like Alpenol ALTRA, TTL, KV and EXC-2 are engineered specifically for PC/PV blends and high-density dobby fabrics.

Reference Links 

1. https://textiletoday.com.bd

2. https://www.mdpi.com/journal/textiles

3. https://aatcc.org

4. https://www.sciencedirect.com/topics/materials-science/textile-sizing

5. https://www.tandfonline.com

6. https://www.textilelearner.net

7. https://textilefocus.com

8. https://fashion2apparel.com

9. https://fibermonthly.com

10. https://study.com/academy/topic/textiles.html

11. https://zdhc.org

12. https://global-standard.org (GOTS)

13. https://oekotex.com