Provided is a glass fiber having a low spinning temperature and a low liquidus temperature, and besides, having a large difference between the liquidus temperature and the spinning temperature, and a method of manufacturing the same. The glass fiber of the present invention includes as a glass composition, in terms of mass % on an oxide basis, 50% to 65% of SiO.sub.2, 0% to 3% of Al.sub.2O.sub.3, 0% to 1% of MgO, 0% to less than 0.7% of CaO, 0% to 1% of Li.sub.2O, 10% to 20% of Na.sub.2O, 0% to 2% of K.sub.2O, 6% to 10% of TiO.sub.2, and 15% to 20% of ZrO.sub.2, and has a value for (Na.sub.2O+K.sub.2O)/(MgO+CaO) of 6.0 or more.

The present invention relates to a glass composition which is resistant to alkalis and to acids, in particular for the preparation of reinforcing glass strands, which comprises the following constituents within the limits defined below, as percentages by weight: TABLE-US-00001 SiO.sub.2 ≧58%, preferably ≦65% ZrO.sub.2 15-20% R.sub.2O (R = Na, K or Li) ≧14% K.sub.2O ≦0.1%, preferably ≦0.05%, RO (R = Mg, Ca or Sr) 2.5-6% MgO ≦4% TiO.sub.2 >1 and ≦4% the composition additionally being devoid of F, comprising less than 1% of impurities (Al.sub.2O.sub.3, Fe.sub.2O.sub.3 and Cr.sub.2O.sub.3) and satisfying the following relationships:
ZrO.sub.2+TiO.sub.2≧17%
ZrO.sub.2/TiO.sub.2≧6 It also relates to the use of the glass strands obtained in the reinforcing of inorganic materials, for example cementitious materials, or organic materials, for example plastics, and to the composites including such strands.

The invention discloses a borosilicate glass with high chemical resistance and an application thereof. The borosilicate glass contains 0.25-4.0 wt % of Y.sub.2O.sub.3 based on the oxide. The borosilicate glass has a high chemical stability, a suitable linear thermal expansion coefficient and is suitable for use in the field of pharmaceutical packaging materials.

Provided is a glass fiber having a low spinning temperature and a low liquidus temperature, and besides, having a large difference between the liquidus temperature and the spinning temperature, and a method of manufacturing the same. The glass fiber of the present invention includes as a glass composition, in terms of mass % on an oxide basis, 50% to 65% of SiO.sub.2, 0% to 3% of Al.sub.2O.sub.3, 0% to 1% of MgO, 0% to less than 0.7% of CaO, 0% to 1% of Li.sub.2O, 10% to 20% of Na.sub.2O, 0% to 2% of K.sub.2O, 6% to 10% of TiO.sub.2, and 15% to 20% of ZrO.sub.2, and has a value for (Na.sub.2O+K.sub.2O)/(MgO+CaO) of 6.0 or more.

The invention discloses a borosilicate glass with high chemical resistance and an application thereof. The borosilicate glass contains 0.25-4.0 wt % of Y.sub.2O.sub.3 based on the oxide. The borosilicate glass has a high chemical stability, a suitable linear thermal expansion coefficient and is suitable for use in the field of pharmaceutical packaging materials.

The present invention relates to a chemically resistant glass composition for the production of reinforcing strands which comprises the following constituents within the limits defined below, expressed in mol %: SiO.sub.2 67-72%; ZrO.sub.2 5-9.5%, preferably 7.5%; R.sub.2O (RNa, K and Li) 11-17%; Li.sub.2O 0-5.5%; K.sub.2O 0-5.5%; Na.sub.2O<10%; and CaO 3-9%, the composition furthermore containing less 1% of impurities (Al.sub.2O.sub.3, Fe.sub.2O.sub.3, Cr.sub.2O.sub.3, TiO.sub.2, MgO, SrO, BaO and P.sub.2O.sub.5) and being free of F. It also relates to the glass strands obtained from this composition and to the composites based on an organic or inorganic material containing such strands.

Provided is a glass composition for a glass fiber, which has excellent alkali resistance, acid resistance, and hydrolytic resistance, is useful as a reinforcing material for composite materials such as calcium silicate board and GRC and as a corrosion-resistant material for battery separators or the like, and has a low glass drawing temperature and liquidus temperature of the glass and thus which is excellent in productivity. The glass composition comprises, in mass % on an oxide base, 50 to 65% of SiO.sub.2, 0 to 5% of Al.sub.2O.sub.3, 0 to 10% of CaO, 10 to 20% of Li.sub.2O+Na.sub.2O+K.sub.2O, 0 to 5% of Li.sub.2O, 10 to 20% of Na.sub.2O, 0 to 5% of K.sub.2O, 5 to 10% of TiO.sub.2, and 10 to 20% of ZrO.sub.2 as a glass composition.