Formation of glass fiber chopped strand mat

Sep 12,2022

The glass fiber chopped strand mat is formed by cutting the glass fiber strand cake (untwisted roving is also possible) into 50mm long strands with a cutter, and then settles in a disorderly manner on the stainless steel mesh belt to form a mat. The chopped strands are bonded together by spraying binder + or water spraying, and powdered binder is removed, and then dried at high temperature and shaped. Form emulsion chopped strand mat or powder chopped strand mat.

1. Raw materials

The glass commonly used in FRP products is a calcium-alumina borosilicate with an alkali content of less than one percent. It is often referred to as "E" glass because it was originally developed for electrical insulation systems.

Glass fibers are produced by transporting molten glass from a melting furnace through a platinum jacket containing a large number of small holes, where it is drawn into glass filaments. Filaments for commercial use are typically between 9 and 15 microns in diameter. Before the filaments are aggregated into fibers, the emulsion is attached. The fibers are very strong - the tensile strength is exceptionally high. They also show good chemical and moisture resistance, have excellent electrical properties, are immune to biological attack, and do not burn, with a melting point of 1500°C - excellent performance in plastic reinforcements.

Fiberglass can be used in a variety of ways, chopped into short lengths ("chopped strands"); aggregated into loosely bound ropes ("rovings"); woven into various fabrics, continuous by twisting and doubling the yarn yarn strands. In the UK, the most widely used fibreglass material is chopped strand mat, which consists of strands of fibreglass chopped to about 50mm, held together in mat form using a polyvinyl acetate or polyester binder. The fiberglass chopped strand mat can range in weight from 100 gsm to 1200 gsm and is useful for general reinforcement.

2. Sizing section

The glass fibers are applied from the settling section to the conveying process via the conveyor belt, where the binder is applied. The settling section needs to be kept clean and dry. Combining the powders is carried out by two applicators of powder binders, and a series of demineralized (distilled) water sprays.

On the chopped strand mat, the upper and lower sides are lightly sprayed with distilled water. This operation is a necessary step for better adhesion of the adhesive. A special powder applicator guarantees optimum distribution of the powder. A vibrator between the two applicators enables powder transfer to the underside of the felt.

3. Combine with emulsion

The curtain system used ensures adequate spreading of the adhesive. Excess adhesive will be recovered by a special suction system.

This system allows air to be carried away through the pad and adhesive. The binder will be evenly distributed and excess binder will also be eliminated. Obviously, the adhesive can be reused after filtering the dirt.

The binder is stored in a container in the mixing chamber and transported from a small tank near the felt factory via low pressure piping.

Special devices will keep the tank level constant. The recycled adhesive is also delivered to the tank. The pump transports the adhesive from the storage tank to the gluing section.

4. Production

Glass fiber chopped strand mat is a non-woven fabric made of filaments chopped into 25-50 mm long, randomly laid in a horizontal plane, and held together by means of suitable adhesives. There are two types of binders, powder and emulsion. While the physical properties of composites are determined by the composition of fiber diameter, the choice and amount of binder, the use of the felt and formability.

Chopped strand mat is produced from fiberglass manufacturers' strand cakes, but some often use roving, in part to save space.

Very important for the quality of the mat are good fiber cut-off properties and low static electrical load and low glue usage.

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