The effective application of Alkyl Ketene Dimer (AKD) Wax is crucial for achieving the desired paper properties, from water resistance to printability. NINGBO INNO PHARMCHEM CO.,LTD. provides high-quality AKD Wax and understands the importance of a well-executed sizing process. This guide outlines the key steps involved in the AKD sizing process within paper mills.

1. Preparation of AKD Emulsion

AKD Wax is typically supplied as a solid or waxy substance. To apply it effectively, it must first be converted into a stable emulsion. This involves carefully mixing the AKD Wax with water and suitable emulsifying agents. The temperature control during this stage is critical; AKD needs to be heated above its melting point (generally around 50-60°C) to ensure a homogeneous and stable dispersion. The quality of the emulsion directly impacts the success of the sizing process, affecting particle size and distribution on the paper fibers. NINGBO INNO PHARMCHEM CO.,LTD. recommends specific emulsifier systems for optimal results.

2. Addition to the Pulp Stock

The prepared AKD emulsion is then introduced into the pulp slurry at the wet end of the paper machine. The precise point of addition is important for maximizing the retention of AKD onto the cellulose fibers. Typically, it is added after screening and cleaning processes but before the headbox. Careful dosage control is essential to achieve the target sizing level without over-application, which can lead to various issues. The goal is to achieve uniform distribution of the AKD throughout the pulp furnish.

3. Retention and Distribution

To ensure efficient utilization of the AKD, retention aids may be employed. These additives help to fix the AKD onto the fibers, preventing it from being lost in the water circuit. Adequate mixing within the pulp system is also vital to ensure that the AKD is evenly distributed among the fibers. This uniformity is key to achieving consistent sizing performance across the entire paper sheet.

4. Curing and Drying

Once the AKD is on the fibers, the sizing reaction, or curing, begins. This is a chemical process where AKD reacts with the cellulose to form a hydrophobic ester bond. The curing rate is influenced by time and temperature. The drying section of the paper machine plays a crucial role here, as the elevated temperatures accelerate the curing process. Proper drying conditions are necessary to ensure that the AKD is fully reacted and permanently bonded to the fibers, providing lasting water resistance. The benefits of neutral sizing agent for paper are fully realized during this stage.

5. Quality Control

After production, the sized paper undergoes rigorous quality control tests. These typically include measuring water resistance (e.g., Cobb test), ink holdout, and other relevant paper properties to confirm that the AKD sizing process has met the required specifications. Understanding the challenges in AKD sizing and implementing these steps correctly ensures optimal paper water resistance and printability.

By following these guidelines for the AKD sizing process, paper manufacturers can consistently produce high-quality paper products with excellent sizing characteristics. Partnering with a reputable supplier like NINGBO INNO PHARMCHEM CO.,LTD. ensures access to quality AKD Wax and expert support.