For paper mills, mastering the application of sizing agents is key to producing high-quality paper. Alkyl Ketene Dimer (AKD) sizing has become a standard in modern papermaking due to its effectiveness and environmental advantages. Delving into the mechanism and application process of AKD can help manufacturers optimize its use and achieve superior results. As a dedicated supplier of paper chemicals, we provide a comprehensive overview.

The core of AKD's function lies in its chemical structure and reactivity. AKD molecules, when dispersed in water as an emulsion, contain a reactive lactone ring. During the papermaking process, typically at the wet end or during drying, this ring opens and reacts with the hydroxyl (-OH) groups present on cellulose fibers through an esterification process. This chemical bond forms a stable, hydrophobic layer on the fiber surface. This hydrophobic layer is what imparts resistance to water and ink penetration, commonly referred to as sizing. For mills looking to buy AKD, understanding this mechanism helps in appreciating its benefits for paper strength and water resistance.

The application process for AKD emulsion is crucial for its effectiveness. It is usually added as a dilute emulsion to the pulp slurry before sheet formation. For optimal results, the pH of the system should be maintained in the neutral to slightly alkaline range (pH 7-9), as this is where AKD exhibits its highest reactivity and efficiency. The curing of the AKD reaction, which solidifies the hydrophobic layer, is often facilitated by the heat applied in the paper machine's drying section. Ensuring adequate temperature and time during drying is critical for the complete reaction of AKD with the cellulose, maximizing its sizing and strength-enhancing properties.

When considering the purchase of AKD, paper mills should look for suppliers who can offer tailored emulsions that are stable and compatible with their specific process conditions. Factors like particle size distribution, presence of stabilizers, and concentration of the active AKD ingredient can all influence performance. By correctly applying AKD, manufacturers can achieve significant improvements in paper quality, including enhanced durability, better printability, and excellent resistance to moisture and chemicals. Partnering with a knowledgeable manufacturer ensures you get the most out of your AKD investment.