Requirements for The Use of Glass Fiber Mats

Fiberglass mat is a sheet-like product made of continuous or short-cut filaments which are not oriented and combined together by chemical binder or mechanical action.

1. Hand-paste molding: hand-paste molding process is the main way of glass fiber reinforced plastic production in China, glass fiber mat, continuous mat and sewing mat can be used for hand-paste molding process. The use of sewing felt can reduce the number of layers and improve the efficiency of hand lay-up operation. However, the sewing felt contains more chemical fiber sewing thread, the bubble is not easy to drive away, FRP products needle-like bubbles, and the surface feel rough, not smooth. In addition, the sewing felt is a heavy fabric, the overmolding is worse than the short-cut felt and continuous felt, in the production of complex shaped products, it is easy to form a hole in the bend. Hand-layup molding process requires that the felt has a fast rate of resin penetration, easy to eliminate air bubbles and good moldability and so on.

2. Pultrusion molding: Pultrusion molding process is one of the main uses of continuous felt and sewing felt. It is generally used in combination with untwisted roving. The use of continuous felts and sewn felts for pultruded products significantly improves the circumferential and transverse strength of the products and prevents cracking. The pultrusion molding process requires the felt to have uniform fiber distribution, high tensile strength, fast resin penetration rate, good flexibility and mold filling and the felt should have a certain continuous length and so on.

3.RTM: Resin transfer molding (RTM) is a closed mold molding process. It consists of two half-molds, a negative and a positive mold, and a pressurized pump and injection gun without a press.The RTM process usually uses continuous felts and stitched felts instead of short-cut felts. The felts are required to have the characteristics that the felts should be easy to be soaked by the resin, good air permeability, good resistance to resin scouring, and good mold-covering properties.

4. Winding process: Generally, short-cut and continuous felts are used for winding molding, which are mainly used as the resin-rich layer of the products, including the inner lining layer and the outer surface layer. The requirements of the winding molding process for glass fiber mats are basically similar to those of the hand-layup method.

Centrifugal casting molding: Usually, short-cut mats are used as raw materials. The short-cut felt is pre-positioned in the mold, and then the resin is added to the rotating open mold cavity, and the air bubbles are discharged through centrifugation to make the product dense. The felts are required to have the characteristics of easy penetration and good air permeability.