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.

New glass compositions and applications thereof are disclosed. A glass composition as described herein can include 50 to 55 weight percent SiO.sub.2, 17 to 26 weight percent B.sub.2O.sub.3, 13 to 19 weight percent Al.sub.2O.sub.3, 0 to 8.5 weight percent MgO, 0 to 7.5 weight percent ZnO, 0 to 6 weight percent CaO, 0 to 1.5 weight percent Li.sub.2O, 0 to 1.5 weight percent F.sub.2, 0 to 1 weight percent Na.sub.2O, 0 to 1 weight percent Fe.sub.2O.sub.3, 0 to 1 weight percent TiO.sub.2, and 0 to 8 weight percent of other constituents. Also described herein are glass fibers formed from such compositions, composites, and articles of manufacture comprising the glass compositions and/or glass fibers.

New glass compositions and applications thereof are disclosed. A glass composition as described herein can include 50 to 55 weight percent SiO.sub.2, 17 to 26 weight percent B.sub.2O.sub.3, 13 to 19 weight percent Al.sub.2O.sub.3, 0 to 8.5 weight percent MgO, 0 to 7.5 weight percent ZnO, 0 to 6 weight percent CaO, 0 to 1.5 weight percent Li.sub.2O, 0 to 1.5 weight percent F.sub.2, 0 to 1 weight percent Na.sub.2O, 0 to 1 weight percent Fe.sub.2O.sub.3, 0 to 1 weight percent TiO.sub.2, and 0 to 8 weight percent of other constituents. Also described herein are glass fibers formed from such compositions, composites, and articles of manufacture comprising the glass compositions and/or glass fibers.

A glass composition is disclosed that comprises SiO.sub.2 in an amount from 50 to 58% by weight; Al.sub.2O.sub.3 in an amount from 18 to 23% by weight; less than 18% by weight of CaO and MgO; at least 5% by weight of Y.sub.2O.sub.3 and La.sub.2O.sub.3, wherein Y.sub.2O.sub.3 and La.sub.2O.sub.3 are present in a ratio R1 (R1=Y.sub.2O.sub.3/La.sub.2O.sub.3) between 2 and 4. A glass fiber formed from the glass composition has a sonic fiber elastic modulus of at least 94.5 GPa.

A glass composition is disclosed that comprises SiO.sub.2 in an amount from 50 to 58% by weight; Al.sub.2O.sub.3 in an amount from 18 to 23% by weight; less than 18% by weight of CaO and MgO; at least 5% by weight of Y.sub.2O.sub.3 and La.sub.2O.sub.3, wherein Y.sub.2O.sub.3 and La.sub.2O.sub.3 are present in a ratio R1 (R1=Y.sub.2O.sub.3/La.sub.2O.sub.3) between 2 and 4. A glass fiber formed from the glass composition has a sonic fiber elastic modulus of at least 94.5 GPa.

To provide a glass composition for glass fiber that includes biosolubility and can achieve long fiber formation. The glass composition for glass fiber of the present invention includes SiO.sub.2 in the range of 35.0 to 55.0% by mass, B.sub.2O.sub.3 in the range of 10.0 to 30.0% by mass, Al.sub.2O.sub.3 in the range of 14.5 to 30.0% by mass, and CaO and MgO in the range of 8.7 to 25.0% by mass in total, with respect to the total amount, and the content S of SiO.sub.2, the content B of B.sub.2O.sub.3, the content A of Al.sub.2O.sub.3, the content C of CaO, and the content M of MgO satisfy the following formula (1):

[00001]$\begin{array}{cc}11.3\le \text{S}\times \left(\text{C}+\text{M}\right)/\left(\text{A}+\text{B}\right)\le 20.7& \text{­­­(1)}\end{array}$

To provide a glass composition for glass fiber that includes biosolubility and can achieve long fiber formation. The glass composition for glass fiber of the present invention includes SiO.sub.2 in the range of 35.0 to 55.0% by mass, B.sub.2O.sub.3 in the range of 10.0 to 30.0% by mass, Al.sub.2O.sub.3 in the range of 14.5 to 30.0% by mass, and CaO and MgO in the range of 8.7 to 25.0% by mass in total, with respect to the total amount, and the content S of SiO.sub.2, the content B of B.sub.2O.sub.3, the content A of Al.sub.2O.sub.3, the content C of CaO, and the content M of MgO satisfy the following formula (1):

[00001]$\begin{array}{cc}11.3\le \text{S}\times \left(\text{C}+\text{M}\right)/\left(\text{A}+\text{B}\right)\le 20.7& \text{­­­(1)}\end{array}$

The present disclosure provides a novel glass composition that has a low permittivity and is suitable for mass production. A glass composition provided satisfies, in wt %, for example, 40≤SiO.sub.2≤60, 25≤B.sub.2O.sub.3≤45, 0<Al.sub.2O.sub.3≤18, 0<R.sub.2O≤5, and 0≤RO≤12, and satisfies at least one of: i) SiO.sub.2+B.sub.2O.sub.3≥80 and SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3≤99.9; and ii) SiO.sub.2+B.sub.2O.sub.3≥78, SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3≤99.9, and 0<RO<10. Another glass composition provided includes SiO.sub.2, B.sub.2O.sub.3, Al.sub.2O.sub.3, R.sub.2O, and 3<RO<8 at the same contents as the above, and satisfies SiO.sub.2+B.sub.2O.sub.3≥75 and SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3<97, where R.sub.2O═Li.sub.2O+Na.sub.2O+K.sub.2O and RO═MgO+CaO+SrO.

The present disclosure provides a novel glass composition that has a low permittivity and is suitable for mass production. A glass composition provided satisfies, in wt %, for example, 40≤SiO.sub.2≤60, 25≤B.sub.2O.sub.3≤45, 0<Al.sub.2O.sub.3≤18, 0<R.sub.2O≤5, and 0≤RO≤12, and satisfies at least one of: i) SiO.sub.2+B.sub.2O.sub.3≥80 and SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3≤99.9; and ii) SiO.sub.2+B.sub.2O.sub.3≥78, SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3≤99.9, and 0<RO<10. Another glass composition provided includes SiO.sub.2, B.sub.2O.sub.3, Al.sub.2O.sub.3, R.sub.2O, and 3<RO<8 at the same contents as the above, and satisfies SiO.sub.2+B.sub.2O.sub.3≥75 and SiO.sub.2+B.sub.2O.sub.3+Al.sub.2O.sub.3<97, where R.sub.2O═Li.sub.2O+Na.sub.2O+K.sub.2O and RO═MgO+CaO+SrO.

Provided is a composition for a glass fiber having a high elastic modulus and satisfactory productivity. The composition for a glass fiber includes, in terms of mass %, 0% to 1% of Li.sub.2O+Na.sub.2O+K.sub.2O, and has SiO.sub.2/Al.sub.2O.sub.3 of from 1 to 4 and MgO/CaO of from 0.2 to 3.9 in terms of mass ratio.