What Types Of FRP Products Are Suitable For Making Chopped Strand Mat (CSM)?

Fiberglass chopped strand mat (CSM) is a primary nonwoven fiberglass reinforcement material, the most widely used reinforcement material in FRP (Fiberglass Reinforced Plastic) hand lay-up processes. It is also used in some mechanical molding processes such as RTM (Reinforced Metal Transform), winding, molding, continuous sheet fabrication, and centrifugal casting. Typical applications include boat, automotive, and train parts, corrosion-resistant storage tanks, containers, water tanks, and corrugated sheets. In many large-scale hand lay-up FRP products, CSM is used simultaneously with untwisted roving woven fabric. The non-directional distribution of chopped strands in CSM compensates for the lack of warp and weft distribution in roving woven fabric, while also significantly improving the interlaminar shear strength of the FRP product.

CSM lines are among the larger pieces of equipment in fiberglass manufacturing plants. The width of the mat produced by these lines typically ranges from 1.27 to 4.5 meters. Large lines not only offer high output and efficiency, but also produce uniform mats. The width of the mat sheets can also be slit on the production line according to customer requirements, resulting in a wide range of product adaptability. Therefore, large-scale chopped strand mat (CSM) machines are increasingly popular among fiberglass manufacturers. CSM products are available in g/m² grades of 200, 230, 300, 380, 450, 600, and 900 g/m², with the most common range being 300-600 g/m².

After being processed into fiberglass reinforced plastic (FRP), chopped strand mat contains approximately 30% fiberglass. Because the fiberglasss in chopped strand mat are not continuous and the fiber content within each layer is relatively low, the laminates made from this material have lower strength. However, it also has advantages such as good water tightness, good resin penetration, strong interlayer adhesion, attractive finished product appearance, non-anisotropic strength, ease of application on complex surfaces, and lower cost. It is often used in the outermost layer immediately adjacent to the gel coat and in the middle layers where bending stress is low.