Optimizing AKD Sizing for Better Paper Strength and Water Resistance

What Is AKD and How It Works in Papermaking

Alkyl Ketene Dimer (AKD) is a widely used internal sizing agent in modern papermaking. It reacts with cellulose fibers to create hydrophobic bonds that prevent paper from absorbing water and liquids. Compared with traditional rosin sizing, AKD provides higher sizing efficiency, better durability, and improved paper strength under neutral or weakly alkaline conditions.

The reaction between AKD and cellulose hydroxyl groups forms stable ester bonds, resulting in long-lasting water resistance. This makes AKD ideal for cultural paper, printing paper, packaging board, and various specialty papers.

Key Factors Affecting AKD Sizing Efficiency

Several factors can influence the performance of AKD sizing in paper production:

AKD Emulsion Stability: A uniform and fine-particle emulsion ensures better retention and distribution on fiber surfaces.

Retention and Drainage Aids: Proper use of retention systems (such as cationic polyacrylamide or PolyDADMAC) enhances AKD fixation.

pH and Temperature: AKD performs best in the neutral to slightly alkaline range (pH 7–8.5).

Curing Conditions: Adequate drying and curing temperature are essential for the full development of sizing performance.

CHEMSUN offers both AKD wax and AKD high polymer emulsifiers , designed to optimize these critical parameters and deliver consistent results.

Benefits of AKD for High-Performance Paper

Using AKD sizing provides multiple advantages for paper manufacturers:

Excellent water resistance and printability

Enhanced dry and wet strength of paper

Improved aging stability without yellowing

Reduced system corrosion and scaling

Compatibility with calcium carbonate fillers and neutral papermaking systems

• These properties help papermakers achieve high-quality paper with lower production costs and better environmental performance.

Common Problems and Optimization Tips

Papermakers sometimes face challenges such as poor sizing, foaming, or AKD hydrolysis. To overcome these issues:

Ensure proper AKD dosage and emulsification quality

Use effective retention aids to minimize loss

Control machine temperature and moisture during drying

Avoid excessive shear and overmixing in the approach flow system

CHEMSUN’s technical team provides on-site guidance and formulation optimization to help mills achieve stable and efficient sizing performance.

Choose CHEMSUN for Reliable AKD Solutions

With years of experience in papermaking chemistry, CHEMSUN delivers high-performance AKD products tailored for different paper grades. Our AKD wax , liquid AKD , and polymer emulsifiers ensure strong water repellency, excellent fiber bonding, and superior runnability on paper machines.