2023 Volume 72 Issue 12 Pages 942-945
We have developed a novel transparent hygroscopic film using 4A zeolite with primary particle size of 50 nm, which is shorter than the wavelength of visible light, as a hygroscopic agent. Although zeolite is an excellent moisture absorber in the low humidity range, their moisture absorption capacity is about 20% of the zeolite weight, and this capacity decreases further when surface modification is applied to improve dispersion and transparency. Increasing the amount of zeolite additives is a possible way to increase the moisture absorption capacity of the film, however high concentrations of nano-sized fillers cause difficulties in kneading with the resin. Therefore, in this study, the addition of nano-sized zeolite and another inorganic particle with a large moisture absorption capacity to LLDPE was attempted for use as a hygroscopic agent. Among the many inorganic hygroscopic agents, the combination of burnt alum and zeolite was found to be effective in this study. It was found that by using a small amount of burnt alum in combination with nano-sized zeolite, it was possible to increase the moisture absorption capacity while maintaining the transparency of the hygroscopic film.
