Continuous strand textile glass fibers are fibers used for the reinforcement of various materials. Fibers have a diameter of a few microns and are coated with a silane in order to improve compatibility with the matrix material that they reinforce.
Textile fiber glass (TFG) can be defined by several fiber types: A, C, E-CR, D, E, R and S. These glass fibers come in a variety of forms: rovings, yarns, chopped strands, milled fibers and woven and mat textiles. 90 to 95% of TFG products are considered E-glass, which was originally aimed at electrical applications, but is now mostly used to reinforce thermoset and thermoplastic polymer composite structures. These are often known as FRP – fiber reinforced plastic; or GFRP – glass fiber reinforced plastic. Important applications of these materials are boats, wind turbine blades, pipes, and light-weight composite structural components for cars, trucks, trains and aircraft.
The textile industry has standardized E-glass into two general categories: printed circuit boards and aerospace applications; and general reinforcement applications. The primary difference between the categories is the use of boron. E-glass for PCB must contain between 5 and 10% B2O3, whereas E-glass for general reinforcement purposes can vary from 0 to 10% B2O3. More recently, low dielectric textile glass fibers have begun to appear. These fibers have a higher B2O3 content than E-glass for electronics, in order to have a reduced dielectric constant to make them suitable for high frequency electronics applications.
In textile fiberglass manufacture, borates act as a powerful flux and lower glass batch melting temperatures. In fibers for electronics and aerospace applications, borates also enable control of dielectric properties. In fibers for general reinforcement applications, borates bring no benefits to the final product.