Patent ID: 6846761

Claim:
A low-dielectric-constant glass fiber having a glass composition consisting of, by weight %, 53 to 57% of SiO 2 , 13 to 16% of Al 2 O 3 , 15 to 19% of B 2 O 3 , 3% to less than 6% of MgO, 2 to 4.7% of CaO, 1 to 4% of TiO 2 , 0 to 0.3% of Li 2 O, 0 to 0.3% of Na 2 O, 0 to 0.5% of K 2 O, and 0 to 1% of F 2 , the content of MgO+CaO being 7 to 10% and the content of Li 2 O+Na 2 O+K 2 O being 0.2 to 0.5%, wherein the low-dielectric-constant glass has a dielectric constant of 5.0 or lower, a dielectric tangent 10×10 31 4 or less, a spinning temperature (a temperature at which a glass viscosity comes to be 1×10 2 Pa·s) of 1,350° C. or lower, a B 2 O 3 volatilization amount of 4 ppm or less and a water-resistance loss of 0.5% by weight or less.