Author: Unionchem Publish Time: 2026-03-23 Origin: Qingdao Unionchem Co.,Ltd.
In the fast-paced world of textile manufacturing, the difference between a premium fabric and a reject often lies in the invisible chemistry. Whether it’s the warp sizing that protects threads during high-speed weaving or the printing paste that defines a complex pattern, Polyanionic Cellulose (PAC) is the unsung hero.
While standard CMC is common, high-performance PAC offers superior film-forming strength and desizing efficiency. But with various viscosities and substitution degrees available, how do you pick the right one?
Here is a technical guide for textile engineers on selecting the optimal PAC to enhance fabric quality and production speed.
PAC is not a one-size-fits-all additive. It serves two distinct functions depending on the stage of production:
In Warp Sizing (Weaving): It acts as a protective film. PAC coats the yarn, laying down protruding fibers and increasing abrasion resistance. This prevents yarn breakage on high-speed looms.
In Textile Printing: It acts as a rheology modifier. PAC thickens the dye paste, ensuring the color stays exactly where the screen places it, without bleeding (wicking) into the surrounding fabric.
(Explore our specific Textile Grade PAC Specifications tailored for sizing and printing.)
To choose the right grade, you must evaluate three critical parameters.
For Warp Sizing: Choose Low Viscosity PAC.
Why: You need the size to penetrate the yarn bundle, not just sit on top. Low viscosity ensures deep penetration, strengthening the yarn from the inside out.
For Printing Pastes: Choose High Viscosity PAC.
Why: You need "hold." A high-viscosity paste sits on the fabric surface, resulting in sharper line definition and higher color brilliance (color yield).
The Challenge: After weaving, the size must be removed (desized) completely before dyeing. Residual size causes uneven dyeing.
The Solution: Select High-DS PAC (>0.9).
The Benefit: A higher Degree of Substitution makes the polymer more water-soluble. This means it washes out easily with hot water, reducing the need for harsh enzymes or chemicals during desizing.
The Context: Reactive dyes often require electrolytes (salt/soda ash) for fixation.
The Selection Rule: Ensure your PAC has high salt tolerance. Inferior grades will precipitate or lose viscosity in the presence of salts, causing the printing paste to become watery and the color to bleed.
Let’s look at how the right PAC choice solves specific manufacturing problems.
Application: Rotary Screen Printing on Cotton.
Problem: The intricate floral pattern was losing definition; the red dye was bleeding into the white background.
Solution: Switched to a High-Viscosity, High-Purity PAC.
Result: The paste maintained its structure (pseudoplasticity) under the shear stress of the squeegee. The lines became razor-sharp, and the color yield increased by 15%, saving dye costs.
Application: Sizing of Fine Cotton Yarn.
Problem: Frequent yarn breaks were causing machine downtime. The starch-based size was too brittle.
Solution: Replaced 20% of the starch with Low-Viscosity PAC.
Result: The PAC formed a flexible, tough film that didn't crack. Weaving efficiency improved by 10%, and the subsequent desizing process was faster due to PAC's solubility.
Application: Eco-friendly Sizing.
Problem: The factory wanted to reduce Polyvinyl Alcohol (PVA) usage due to environmental concerns in wastewater treatment.
Solution: PAC as a PVA Substitute.
Result: PAC offered similar film strength but with a much lower Biological Oxygen Demand (BOD) in the wastewater, helping the factory meet environmental discharge regulations.
Choosing the best Polyanionic Cellulose for textiles is a balance of process efficiency and finished quality.
For Sizing: Prioritize penetration and film flexibility (Low Viscosity).
For Printing: Prioritize sharp definition and color yield (High Viscosity).
For Environment: Prioritize high DS for easy washout.
At Unionchem, we understand the delicate chemistry of textiles. Our PAC grades are engineered to replace or enhance traditional sizes like starch and alginate, offering a modern solution for modern fabrics.
Upgrade your textile chemistry.Check our PAC Product List or contact our lab for a sample to test in your sizing or printing formula.
Q1: Can PAC replace Sodium Alginate in reactive printing?
A: Yes, in many cases. PAC is often more cost-effective and offers higher color yield. While Alginate is the traditional standard for reactive dyes, high-quality PAC is an excellent alternative or extender, especially for cotton and rayon.
Q2: Does PAC work with synthetic fibers like Polyester?
A: Yes. PAC is an excellent sizing agent for blends (e.g., Polyester/Cotton). Its adhesion to both natural and synthetic fibers makes it a versatile binder in the sizing mix.
Q3: Is PAC hard to remove (desize)?
A: No, quite the opposite. PAC is water-soluble. Unlike starch, which requires enzymes to break down, PAC washes off easily with hot water, simplifying the pre-treatment process for dyeing.
Q4: How does PAC affect the "hand" (feel) of the fabric?
A: In sizing, PAC forms a smooth film that reduces friction. In printing, because it allows for lower solid content in the paste compared to starch, it often results in a softer hand after washing.
