Application of Synthetic Fiber in Air Filter Paper

Synthetic fibers have characteristics that plant fibers do not have, such as water resistance, chemical resistance, heat resistance, and thermal stability. If mixed with plant fibers and applied to make air filter paper, then the required properties of paper could be obtained. Two kinds of synthetic fiber, polypropylene (PP) and polyester (PET), were mixed with softwood pulp to make air filter base paper. The effects of the mixing ratio, the beating degree of softwood pulp, the variety and addition amount of reinforcing agents, and the process of pressing and drying on the properties of base paper were explored. Samples were found to meet the requirements of the physical properties and porosity of the filter paper base paper at the same time when the mixing ratio of synthetic fiber and plant fiber was 20/80, the beating degree of softwood pulp was 22 °SR, and the added amount of cationic polyacrylamide (CPAM) was 0.06%. The PP fiber fell off easily from the page, but PET fiber did not. The addition of PET fiber increased the porosity, tear index, and folding endurance of the paper. In sum, PET fiber was more suitable for making air filter paper than PP fiber.