What raw materials are needed for the production of FRP pultruded products

Raw materials of FRP pultrusion Profile

-Resin

-Glass fiber (twistless roving, surface felt, gingham cloth, etc.)

-Curing agent (medium and high temperature curing agents such as TBPB/BPO and low temperature curing agents such as methyl ethyl ketone peroxide)

-Fillers (calcium carbonate, aluminum hydroxide, glass beads, etc.)

-Release agents, low shrinkage agents and other additives

The basic components of FRP profiles are resin and glass fiber. The raw materials used in the pultrusion process can be divided into three categories: reinforcement materials, matrix materials and additives. The selection of raw materials and the adjustment of their respective proportions can derive a range of composite material properties.

1. Reinforcement materials

A widely used reinforcing material is fiberglass, which comes in many forms. Glass fibers are the load-bearing component of composite materials and provide the required mechanical properties (strength, modulus, impact resistance, etc.). A commonly used and economical reinforcing material is E-glass fiber roving, which has different tex numbers. By using untwisted rovings, fiber aggregation can be achieved under a given volume, resulting in very high strength in the longitudinal direction of the profile, and the fiber mass fraction in pultrusion can reach 80%. Continuous mats are often used for transverse reinforcement of pultruded profiles, sometimes with stitchbonded rovings or composite reinforcements used in drafting.

2. Base material

The type and form of fibers determines the strength of the composite, while other properties of the composite, such as corrosion resistance, electrical properties and high temperature performance, are determined by the resin matrix. To achieve these properties, resins are carefully selected. Unsaturated polyester is a common resin in the pultrusion process. It can be divided into o-phenylene type and m-phenylene type according to different raw materials. Other resins, such as phenolic resins (which have excellent flame retardant properties) and resins based on methyl methacrylate as the monomer (which can use a high proportion of fillers due to their low viscosity), are also gradually being used in the field of pultrusion.

3. Additives

Pultrusion liquid contains various additives, such as catalysts, release agents, flame retardants, low shrinkage agents, mineral fillers, etc., which mainly play the role of flame retardant, improve processability, reduce costs, and improve surface finish.