1. Overview

Glass fiber felt by continuous raw silk or chopped raw silk is not directed through the chemical binder or mechanical effect of the combination of thin-shaped products.

According to the different forms of fiber and the way of bonding, there are mainly short cut original silk felt, continuous original silk felt, seam knitting felt, composite felt and surface felt and other categories.

2. Use and Requirements

2.1 Hand Paste Molding

Hand lay-up Molding technology is the main way of FRP production in China, glass fiber chopped strand felt, continuous felt and seam knitting felt can be used in hand lay-up molding process. The use of seam knitting blanket can reduce the number of layers, improve the efficiency of hand lay-up.

However, because it contains more chemical fiber seam weaving line, bubble is not easy to drive, fiberglass products needle-like bubbles more, and surface feel rough, not smooth.

In addition, the seam is woven thick fabric, the laminating is shorter than the strand felt and continuous felt to be poor, in the production of complex products, in the bending place easy to form voids.

The process of hand lay-up requires that the felt plate has the characteristics of fast resin soak rate, easy to eliminate bubble and good laminating.

2.2 Pultrusion Molding

Pultrusion Molding process is one of the main uses of continuous felt and seam felting. Generally used in combination with the use of roving.

Using continuous felt and seam knitting felt as pultrusion products, can significantly improve the product’s circumferential and transverse strength, prevent product cracking.

The pultrusion process requires that the felt plate has the characteristics of uniformity of fiber distribution, high tensile strength, fast resin penetration rate, good softness and mold filling, and a certain continuous length of felt film.

2.3 RTM：

Resin transfer Molding (RTM) is a closed-form molding process. It is composed of two halves of the die and master and a pressurized pump and an injection gun without pressing the machine.

The RTM process is usually made of continuous felts and seam felts, without the use of chopped strand mats. It is required that the felt piece should be easy to be soaked by resin, good permeability, good scouring resistance and good laminating properties.

2.4 Winding Process

Short-cut felt and continuous felts are generally used for winding and forming the resin-rich layer, including inner liner and outer surface layer. The requirement of filament-wound forming process is similar to that of hand lay-up.

2.5 Centrifugal Casting Molding

Chopped felts are usually used as raw materials. The chopped strand mat is laid in the mould, then the resin is added to the rotating opening cavity, and the product is compacted by centrifugal discharge of the bubbles. It is required that the felt film is easy to soak and breathable.