A silicate-based glass composition includes: 40-60 wt. % SiO.sub.2, 0-10 wt. % B.sub.2O.sub.3, 0.01-10 wt. % P.sub.2O.sub.5, 0-10 wt. % Al.sub.2O.sub.3, 0-5 wt. % Li.sub.2O, 10-30 wt. % Na.sub.2O, 0.01-15 wt. % K.sub.2O, 0.01-5 wt. % MgO, 15-30 wt. % CaO, 15-35 wt. % MO, and 15-30 wt. % R.sub.2O, such that MO is the sum of MgO, CaO, SrO, BeO, and BaO, and R.sub.2O is the sum of Na.sub.2O, K.sub.2O, Li.sub.2O, Rb.sub.2O, and Cs.sub.2O.

A bioactive glass composition including: 50 to 70% SiO.sub.2; 0.1 to 10% Al.sub.2O.sub.3, 5 to 30% Na.sub.2O, 0.1 to 15% K.sub.2O, 0.1 to 15% MgO, 0.1 to 20% CaO, and 5 to 10% P.sub.2O.sub.5, based on a 100 wt % of the composition. Also disclosed is a method of making the bioactive glass composition.

A bioactive glass composition including: 50 to 70% SiO.sub.2; 0.1 to 10% Al.sub.2O.sub.3, 5 to 30% Na.sub.2O, 0.1 to 15% K.sub.2O, 0.1 to 15% MgO, 0.1 to 20% CaO, and 5 to 10% P.sub.2O.sub.5, based on a 100 wt % of the composition. Also disclosed is a method of making the bioactive glass composition.

A glass composition for a glass fiber, contains: in mass %, SiO.sub.2: 50% to 65%, Al.sub.2O.sub.3: 12.3% to 13.7%, B.sub.2O.sub.3: 1.1% to 5.5%, MgO: 0% to 10%, CaO: 15% to 30%, ZnO: 0% to less than 1%, Li.sub.2O: 0% to less than 1%, Na.sub.2O: 0% to 2%, K.sub.2O: 0% to 2%, TiO.sub.2: 0% to less than 0.5%, SiO.sub.2+MgO+CaO: 79% to 86%, Li.sub.2O+Na.sub.2O+K.sub.2O: 0% to 2%, and being substantially free of P.sub.2O.sub.5, wherein (SiO.sub.2+MgO+CaO)/MgO is 30 to 80, and (MgO+CaO)/MgO is 8 to 18 in a mass ratio.

A glass composition for a glass fiber, contains: in mass %, SiO.sub.2: 50% to 65%, Al.sub.2O.sub.3: 12.3% to 13.7%, B.sub.2O.sub.3: 1.1% to 5.5%, MgO: 0% to 10%, CaO: 15% to 30%, ZnO: 0% to less than 1%, Li.sub.2O: 0% to less than 1%, Na.sub.2O: 0% to 2%, K.sub.2O: 0% to 2%, TiO.sub.2: 0% to less than 0.5%, SiO.sub.2+MgO+CaO: 79% to 86%, Li.sub.2O+Na.sub.2O+K.sub.2O: 0% to 2%, and being substantially free of P.sub.2O.sub.5, wherein (SiO.sub.2+MgO+CaO)/MgO is 30 to 80, and (MgO+CaO)/MgO is 8 to 18 in a mass ratio.

A glass composition is provided that includes about 55.0 to 60.4% by weight SiO.sub.2, about 19.0 to 25.0% by weight Al.sub.2O.sub.3, about 8.0 to 15.0% by weight MgO, about 7 to 12.0% by weight CaO, less than 0.5% by weight Li.sub.2O, 0.0 to about 1.0% by weight Na.sub.2O, and 0 to about 1.5% by weight TiO.sub.2. The glass composition has a fiberizing temperature of no greater than about 2,500° F. Glass fibers formed from the inventive composition may be used in applications that require high stiffness, and low weight. Such applications include woven fabrics for use in forming wind blades and aerospace structures.

A glass composition is provided that includes about 55.0 to 60.4% by weight SiO.sub.2, about 19.0 to 25.0% by weight Al.sub.2O.sub.3, about 8.0 to 15.0% by weight MgO, about 7 to 12.0% by weight CaO, less than 0.5% by weight Li.sub.2O, 0.0 to about 1.0% by weight Na.sub.2O, and 0 to about 1.5% by weight TiO.sub.2. The glass composition has a fiberizing temperature of no greater than about 2,500° F. Glass fibers formed from the inventive composition may be used in applications that require high stiffness, and low weight. Such applications include woven fabrics for use in forming wind blades and aerospace structures.

Provided are a surface-treated glass cloth capable of enhancing insulation reliability when used to prepare a prepreg, a prepreg and a printed wiring board using the surface-treated glass cloth. The surface-treated glass cloth includes a surface treatment layer on a surface, a glass constituting the glass cloth has a composition containing 52.0 to 60.0 mass % of SiO.sub.2, 15.0 to 26.0 mass % of B.sub.2O.sub.3, 9.0 to 18.0 mass % of Al.sub.2O.sub.3, 1.0 to 8.0 mass % of MgO, 1.0 to 10.0 mass % of CaO, 0 to 6.0 mass % of SrO, 0 to 6.0 mass % of TiO.sub.2, and 0.1 to 3.0 mass % in total of F.sub.2 and Cl.sub.2, based on the total amount of the glass, the glass cloth has a surface coverage of 75.0 to 100.0% and a thickness of 8 to 95 μm, and the surface treatment layer contains a silane coupling agent having a methacrylic group and contains no surfactant.

Provided are a surface-treated glass cloth capable of enhancing insulation reliability when used to prepare a prepreg, a prepreg and a printed wiring board using the surface-treated glass cloth. The surface-treated glass cloth includes a surface treatment layer on a surface, a glass constituting the glass cloth has a composition containing 52.0 to 60.0 mass % of SiO.sub.2, 15.0 to 26.0 mass % of B.sub.2O.sub.3, 9.0 to 18.0 mass % of Al.sub.2O.sub.3, 1.0 to 8.0 mass % of MgO, 1.0 to 10.0 mass % of CaO, 0 to 6.0 mass % of SrO, 0 to 6.0 mass % of TiO.sub.2, and 0.1 to 3.0 mass % in total of F.sub.2 and Cl.sub.2, based on the total amount of the glass, the glass cloth has a surface coverage of 75.0 to 100.0% and a thickness of 8 to 95 μm, and the surface treatment layer contains a silane coupling agent having a methacrylic group and contains no surfactant.

A glass composition is provided that includes SiO.sub.2 in an amount from 50.0 to 65.0% by weight; Al.sub.2O.sub.3 in an amount from 18.0 to 23.0% by weight; CaO in an amount from 1 to 8.5% by weight; MgO in an amount from 9.0 to 14.0% by weight; Na.sub.2O in an amount from 0.0 to 1.0% by weight; K.sub.2O in an amount from 0.0 to 1.0% by weight; Li2O in an amount from 0.1 to 4.0% by weight; TiO.sub.2 in an amount from 0.0 to 2.5% by weight, Y.sub.2O.sub.3 in an amount from 0 to 10.0% by weight; La.sub.2O.sub.3 in an amount from 0 to 10.0% by weight; Ce.sub.2O.sub.3 in an amount from 0 to 5.0% by weight; and Sc.sub.2O.sub.3 in an amount from 0 to 5.0% by weight. Glass fibers formed from the inventive composition may be used in applications that require high stiffness and have elastic modulus between 88 and 115 GPa. Such applications include woven fabrics for use in forming wind turbine blades and aerospace structures.