Hot-melt coating is a promising technique that eliminates the need for solvents, making it an eco-friendly alternative to traditional coating methods. Unlike conventional processes that rely on organic solvents or water to dissolve or disperse the coating material, hot-melt coating applies the material in its molten state directly onto the substrate. This approach not only reduces environmental impact but also simplifies the production process by removing solvent evaporation and disposal steps. Over the past decade, this technology has gained significant attention, particularly in industries such as pharmaceuticals, food, and metals, where it offers benefits like improved drug stability, controlled release, and enhanced product quality.
Despite its advantages, the use of hot-melt coating in the domestic pharmaceutical industry remains limited compared to other regions. While water-based coatings are more commonly used, they face challenges such as microbial contamination and incompatibility with certain hydrolyzable drugs. In contrast, hot-melt coating provides a more stable and reliable solution in these cases. Additionally, the amount of hot-melt wax required is significantly less than that of traditional polymers, leading to cost savings and improved efficiency.
In a recent study, researchers used Compritol 888ATO as a coating material and tested its performance using theophylline as a model drug. They investigated key parameters such as coating temperature, atomization pressure, and spray rate, while also analyzing how particle size and uniformity affected the coating process. The experiments were conducted in a GLATTGPCG-1.1 system under top-spray conditions, with specific settings including an air flow of 70 m³/h, inlet temperature between 75–78°C, and a coating temperature of 120°C.
The results showed that coating temperature played a critical role in determining the effectiveness of the coating. At 60°C, the drug release was only slightly reduced, while at 67°C, a sustained release profile was observed. This indicated that the coating material needed to be at an optimal temperature to ensure proper adhesion and film formation. The melting point of Compritol 888ATO (69–74°C) further emphasized the importance of precise temperature control during the process.
Other factors, such as droplet size, atomizing air pressure, and the viscosity of the molten material, also influenced the coating efficiency. Smaller droplets led to better coverage and higher coating efficiency, while excessive spray rates could cause aggregation and uneven distribution. Particle size was another important variable—smaller particles tended to have higher coating weights, which affected the release behavior of the drug.
Overall, the study highlighted the potential of hot-melt coating technology in pharmaceutical applications, demonstrating its ability to enhance drug performance while reducing costs and environmental impact. As research continues, this method may become a preferred choice for formulating controlled-release dosage forms.
Low Temperature Scouring and Bleaching
Low temperature scouring agent relates to the pretreatment process of printing and dyeing industry. The invention is scientifically prepared by efficient surface active agent and effective chemical additives, and can complete desizing, boiling and bleaching treatment of cotton and linen, chemical fiber and blended fabric at 45℃ ~ 60℃ for 1 hour, effectively remove the size, cotton seed shell, pigment and impurities on the surface of the fabric, improve the whiteness of the fabric, and almost do not damage the fiber. The invention has the advantages of energy saving, short process flow, improving quality and reducing labor intensity of workers, and has obvious economic and social benefits.
Low temperature scouring and bleaching, low temperature pretreatment auxiliary, cold-pad-batch, batch-steaming, continuous pad-steaming process
Dymatic Chemicals, Inc. , https://www.dymachem.com