Today we will introduce the second part of raw material for FRP products. We mainly talk about auxiliary material.

Colorant

Colorants in pultrusion generally appear in the form of pigment paste

filler

Filler can reduce the shrinkage rate of the product, improve the dimensional stability of the product, surface finish, smoothness and flatness or no lightness; Effectively adjust the viscosity of the resin to meet different performance requirements, improve wear resistance and improve conductivity and thermal conductivity, etc. Most of the fillers can improve the impact strength and compressive strength of the material, but can not improve the tensile strength; Filler can improve the coloring effect of the pigment; Some fillers have excellent light stability and chemical resistance; Filler can reduce cost and the particle size of the filler should be selected to have a gradient to achieve the best results.

Release agent

The release agent has extremely low surface free performance and can uniformly wet the surface of the mold to achieve the release effect. The excellent demolding effect is the main condition for ensuring the smooth progress of the pultrusion process.

In the early pultrusion process, an external release agent was used, and silicone oil was commonly used. However, the dosage is very large, the surface quality of the product is not ideal, and the internal release agent has been used.

The internal mold release agent is directly added to the resin, and is oozing out from the resin matrix to the surface of the cured product under a certain processing temperature condition, and a layer of separator is stretched between the mold and the product to release the mold.

The internal mold release agent generally has a phosphate ester, a lecithin, a stearate, a triethanolamine oil and so on. Among them, the release effect of zinc stearate is better. In pultrusion production, it is generally preferred to use an internal mold release agent that is liquid at room temperature. Most of the commercially available internal release agents are primary amines, mixtures of secondary amines and organic phosphonates with fatty acid copolymers.