Due to the low mass per unit area of lightweight chopped strand mat, the uniformity of the chopped strand fiber distribution within the mat significantly impacts its tensile strength. Uneven distribution of the chopped strand fibers can lead to uneven distribution in all directions, uneven thickness, or the formation of holes. This can cause cosmetic defects or breakage during winding, impacting normal production. Therefore, controlling fiber dispersion uniformity is a crucial step in chopped strand mat production.
Many factors can influence the uneven distribution of chopped strand fibers, but they can be broadly categorized into four categories: raw yarn quality, equipment, environmental factors, and human factors. In terms of raw yarn quality, a special sizing formula is used to produce the raw yarn, with a single-filament linear density of 15-20 tex and a stiffness of 90-110 mm, resulting in excellent chopped strand dispersion. Regarding the equipment, a rotating mechanical disperser is designed below the chopper. Once the yarn bundles are cut, they are evenly dispersed by the high-speed rotating disperser. Furthermore, the wind pressure and direction in the forming chamber are carefully controlled to control the direction of the chopped strands. The temperature in the creel and chopped strand forming chambers is controlled between 15-30°C, and the humidity is maintained between 70% and 90%. These designs and adjustments ensure that the fibers are evenly distributed onto the mesh belt, ensuring uniform quality per unit area of the chopped strand mat.
