Why is it recommended to use powder chopped strand mat for making FRP molds?

June 14,2022

As a basic product in the glass fiber reinforced plastic industry, chopped strand mat (also called CSM) is widely used in the molding of glass fiber reinforced plastic molds and parts. In general, chopped strand mats for polyester resin systems are available from almost any composite supplier with minimal price and quality variation.

For many mold manufacturers, it is generally believed that the weight of chopped strand mat determines the resin infiltration speed, such as 300g or 450g, but this is not entirely the case.

There are also subtle differences between chopped strand mats. It is divided into emulsion and powder formulations, that is, the types of coupling agents on the surface of glass fiber are different. This is very important, but it is often overlooked. To put it simply, the powder form is relatively soft and fluffy, and the dipping speed is fast, but the appearance and tailoring are not as good as the emulsion form, which is why most manufacturers still use the emulsion form.

However, for the manufacture of FRP molds, this is a large cost investment, and the factors that are conducive to the manufacture of molds must be carefully considered.

Because the powder chopped strand mat is softer, it is easier to stick to the surface of the original mold, such as some corners or deep positions, thus avoiding the problems of the chopped strand mat being repeatedly bounced, unable to be pressed down, and the generation of air bubbles. This problem can be avoided by using powdered chopped strand mat.

In addition, powder chopped strand mat can be used in all resin systems, including epoxy, polyester, vinyl, and phenolic; however, emulsion chopped strand mat will bond much worse with epoxy, so if you only use a short strand If you are cutting felt or are not sure which one to use, it is recommended that you use powdered chopped strand felt.

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