Glass compositions suitable for fiber forming having low levels of Li.sub.2O and glass fibers having high-modulus are disclosed. The glass composition may include SiO.sub.2 from about 59 to about 63 weight percent, Al.sub.2O.sub.3 from about 13.7 to about 16 weight percent, CaO from about 14 to about 16.5 weight percent, MgO from about 6 to about 8.5 weight percent, Fe.sub.2O.sub.3 less than 1 weight percent, and TiO.sub.2 less than 1 weight percent. In some cases, the composition may be substantially free of Li.sub.2O. In some cases, the composition may include Li.sub.2O up to 0.5 weight percent. In some cases, RE.sub.2O.sub.3 may be present in the composition in an amount up to 1.5 weight percent. The glass compositions can be used to form glass fibers which can be incorporated into a variety of other fiber glass products (e.g., strands, rovings, fabrics, etc.) and incorporated into various composites.

Provided is a glass fiber-reinforced resin molded article having high dimension stability and low dielectric characteristics. In the glass fiber-reinforced resin molded article, the fiber diameter D of glass fiber included in the glass fiber-reinforced resin molded article is in the range of 5.0 to 15.0 μm, the dielectric constant Dk at a measurement frequency of 1 GHz of the glass fiber is in the range of 4.0 to 7.0, the linear expansion coefficient C of the glass fiber is in the range of 2.0 to 6.0 ppm/K, the number average fiber length L of the glass fiber is in the range of 150 to 400 μm, and the D, Dk, C, and L satisfy the following formula (1):

57.9≤Dk×C.sup.1/4×L.sup.1/2/D.sup.1/4≤70.6  (1)

Provided is a glass direct roving that can achieve good productivity for long glass fiber-reinforced thermoplastic resin pellets, and achieve excellent spinning productivity and good strength of glass fiber-reinforced resin molded articles produced by using long glass fiber-reinforced thermoplastic resin pellets in combination. The glass direct roving includes a plurality of glass filaments bundled together, wherein the filament diameter of the glass filaments, D, is in the range of 17.5 to 21.5 μm, the number of the glass filaments bundled, F, is in the range of 3000 to 7000, the mass of the glass direct roving is in the range of 2450 to 4000 tex, the ignition loss of the glass direct roving, L, is in the range of 0.03 to 0.90%, and the D, F, and L satisfy the following formula (1): $\begin{array}{cc}1050\le \left(D^4\times F^{1/4}\right)/\left(1000\times L^{1/6}\right)\le 1640.& \left(1\right)\end{array}$

Provided is a glass direct roving that can achieve good productivity for long glass fiber-reinforced thermoplastic resin pellets, and achieve excellent spinning productivity and good strength of glass fiber-reinforced resin molded articles produced by using long glass fiber-reinforced thermoplastic resin pellets in combination. The glass direct roving includes a plurality of glass filaments bundled together, wherein the filament diameter of the glass filaments, D, is in the range of 17.5 to 21.5 μm, the number of the glass filaments bundled, F, is in the range of 3000 to 7000, the mass of the glass direct roving is in the range of 2450 to 4000 tex, the ignition loss of the glass direct roving, L, is in the range of 0.03 to 0.90%, and the D, F, and L satisfy the following formula (1): $\begin{array}{cc}1050\le \left(D^4\times F^{1/4}\right)/\left(1000\times L^{1/6}\right)\le 1640.& \left(1\right)\end{array}$

A soundproofing material including a porous body having a cell structure and including inorganic fibers other than asbestos, wherein an average cell diameter is more than 300 μm and 1000 μm or less, a bulk density is 0.007 to 0.024 g/cm.sup.3, and a flow resistivity is 170,000 to 2,000,000 Ns/m.sup.4.

A soundproofing material including a porous body having a cell structure and including inorganic fibers other than asbestos, wherein an average cell diameter is more than 300 μm and 1000 μm or less, a bulk density is 0.007 to 0.024 g/cm.sup.3, and a flow resistivity is 170,000 to 2,000,000 Ns/m.sup.4.

To provide a glass composition for glass fiber having a low dielectric loss tangent, suppressing the occurrence of phase separation, having a reduced viscosity at high temperatures, and reducing the occurrence of striae. The glass composition for glass fiber includes 52.0 to 57.5% by mass of SiO.sub.2, 19.5 to 25.5% by mass of B.sub.2O.sub.3, 8.0 to 13.0% by mass of Al.sub.2O.sub.3, 0 to 2.0% by mass of MgO, 0 to 6.0% by mass of CaO, 0.5 to 6.5% by mass of SrO, and 0.1 to 3.0% by mass of TiO.sub.2, the ratio of Al.sub.2O.sub.3 to B.sub.2O.sub.3 is 0.35 to 0.54, and the content SI of SiO.sub.2, the content B of B.sub.2O.sub.3, the content M of MgO, the content C of CaO, the content SR of SrO, and the content T of TiO.sub.2 satisfy the following formula (1): 6.90≤100×(B/SI).sup.2×{SR/(C+SR)}.sup.2/3×{T/(M+T)}.sup.1/2≤12.30 (1).

To provide a glass composition for glass fiber having a low dielectric loss tangent, suppressing the occurrence of phase separation, having a reduced viscosity at high temperatures, and reducing the occurrence of striae. The glass composition for glass fiber includes 52.0 to 57.5% by mass of SiO.sub.2, 19.5 to 25.5% by mass of B.sub.2O.sub.3, 8.0 to 13.0% by mass of Al.sub.2O.sub.3, 0 to 2.0% by mass of MgO, 0 to 6.0% by mass of CaO, 0.5 to 6.5% by mass of SrO, and 0.1 to 3.0% by mass of TiO.sub.2, the ratio of Al.sub.2O.sub.3 to B.sub.2O.sub.3 is 0.35 to 0.54, and the content SI of SiO.sub.2, the content B of B.sub.2O.sub.3, the content M of MgO, the content C of CaO, the content SR of SrO, and the content T of TiO.sub.2 satisfy the following formula (1): 6.90≤100×(B/SI).sup.2×{SR/(C+SR)}.sup.2/3×{T/(M+T)}.sup.1/2≤12.30 (1).

Glass fibers formed from the inventive composition may be used in applications that require high stiffness and have a specific modulus between 34 and 40 MJ/kg. Such applications include woven fabrics for use in forming wind turbine blades and aerospace structures.

Glass fibers formed from the inventive composition may be used in applications that require high stiffness and have a specific modulus between 34 and 40 MJ/kg. Such applications include woven fabrics for use in forming wind turbine blades and aerospace structures.