The roving is a bundle of parallel or filament without twisting and is one of the basic type of glass fiber products. The roving can be divided into: alkali-free glass roving and medium-alkali glass roving. The number of rovings is from 150 to 9600 tex, and the diameter of the glass fibers used for rovings is from 12 to 23 μm, all types of rovings use enhanced sizing. The roving has excellent antistatic property, moisture absorption resistance, bundling & banding property, and few hairiness and can be quickly and thoroughly saturated in the resin, and is widely used. Depending on the application, the rovings are basically divided into two categories, one is chop roving, which is hard roving, and the other is soft roving for woven or twining applications.
Roving for jetting
The roving for jetting is also called jet yarn. It is suitable for FRP injection molding. The raw yarn drawn by special sizing agent is made up of multiple strands. The original yarn contains 200 glass filaments. The specific method of preparation is to use a spray gun to cut the glass fiber roving and spray it onto the surface of the resin together with the resin, and then use a roller to flatten the product and remove the bubbles simultaneously. The main production of FRP products are pipes, sanitary ware, auto parts and so on.
In the preform process, the roving is chopped and sprayed on a web of a pre-designed shape, while spraying a small amount of resin to fix the fiber web, and then moving the formed fiber web into the metal mold, and injecting the resin into hot press forming, that is the product.
SMC is a sheet molding compound used mainly for pressing automobile parts, bathtubs, water tank panels, various seats, etc. SMC uses a roving to cut into a length of 25 mm when the SMC sheet is manufactured, and is dispersed in the resin paste. Normally, the SMC roving is 2400 tex.
Roving for winding and pultrusion
Winding and pultrusion rovings are mainly used in the manufacture of small-diameter pipes, storage tanks and bars. They are widely used in consumer goods and commercial facilities, sports and leisure, infrastructure, construction, transportation, aerospace, military defense, electrical and electronic, etc. The number of rovings for winding and extrusion is from 1100 to 9600 tex, Direct roving are used for large pipes and tanks.
Roving for weaving
An important use of rovings is to weave woven or unidirectional roving fabrics of various thicknesses, which are important substrates for hand lay-up FRP. The roving for weaving requires good abrasion resistance and permeability. The roving for weaving needs to be forced to dry before weaving to ensure even tension.
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