Abstract: The invention relates to glass reinforcing yarns, the composition of which comprises the following constituents, within the limits defined below, expressed in percentages by weight: SiO2 50-65% Al2O3 12-20% CaO 13-16% MgO 6-12% B2O3 0-3% TiO2 0-3% Na2O + K2O <2% F2 0-1% Fe2O3 <1.?? These yarns are made of a glass offering an excellent compromise between its mechanical properties represented by the specific Young's modulus and its melting and fiberizing conditions.

Abstract: The invention relates to glass reinforcement strands, the composition of which comprises the following constituents in the limits defined below, expressed as percentages by weight: 59 to 63% SiO2; 10 to 16% Al2O3; 16 to 23% CaO; 1 to 3.2% MgO; 0 to 2% Na2O+K2O+Li2O; 0 to 1% TiO2; 0.1 to 1.8% B2O3; 0 to 0.5% Li2O; 0 to 0.4% ZnO; 0 to 1% MnO; and 0 to 0.5% F. These strands have improved properties in terms of mechanical strength, acid resistance and high-temperature resistance for a low-cost composition. The invention also relates to a process for producing the said strands and to the composition allowing them to be produced.

Abstract: The invention relates to glass reinforcement strands, the composition of which comprises the following constituents in the limits defined below, expressed as percentages by weight: 58 to 63% SiO2; 10 to 16% Al2O3; 16 to 23% CaO; 0.5 to 3.5% MgO; 0 to 2% Na2O+K2O+Li2O; 1 to 1.5% TiO2; 0 to 1.5% B2O3; 0 to 0.4% Li2O; 0 to 0.4% ZnO; 0 to 1% MnO; and 0 to 0.5% F. These strands have improved properties in terms of mechanical strength, acid resistance and high-temperature resistance for a low-cost composition. The invention also relates to a process for producing the said strands and to the composition allowing them to be produced.

Abstract: Glass reinforcement strand, the composition of which comprises the following constituents, within the limits defined below, expressed as percentages by weight: SiO2 50 to 60%, preferably SiO2 ? 52% and/or SiO2 ? 57%; Al2O3 10 to 19%, preferably Al2O3 ? 13% and/or Al2O3 ? 17%; B2O3 16 to 25%; ZrO2 0.5 to 1.5%; Na2O ?1.5%, preferably Na2O ? 0.8%; K2O ?1.5%, preferably K2O ? 0.8%; R2O ?2%, preferably R2O ? 1%; CaO ?10%; MgO ?10%; F 0 to 2%; TiO2 0 to 3%; RO 4 to 15%, preferably RO ? 6% and/or RO ? 10%; and Various ?3%, where R2O = Na2O + K2O + Li2O, and RO = CaO + MgO. The dielectric properties of such glass compositions are particularly advantageous in the MHz and GHz ranges.

Abstract: Reinforcing glass yarn, the composition of which comprises the following constituents, within the limits defined below, expressed in percentages by weight: SiO2 54.5 to 58% Al2O3 12 to 15.5% SiO2 + Al2O3 70 to 73% CaO 17 to 25% MgO 0 to 5% RO = CaO + MgO 21 to 28% R2O = Na2O + K2O + Li2O up to 2% TiO2 less than 1% Fe2O3 less than 0.5% B2O3 up to 3% F2 less than 1% and such that the ratio R1=Al2O3/CaO is less than 0.7, and when SiO2 is greater than 57% the amount of boron oxide B2O3 is greater than 2%.

Abstract: The invention relates to glass reinforcement strands, the composition of which comprises the following constituents in the limits defined below, expressed as percentages by weight: 59 to 63% SiO2; 10 to 16% Al2O3; 16 to 23% CaO; 1 to 3.2% MgO; 0 to 2% Na2O+K2O+Li2O; 0 to 1% TiO2; 0.1 to 1.8% B2O3; 0 to 0.5% Li2O; 0 to 0.4% ZnO; 0 to 1% MnO; and 0 to 0.5% F. These strands have improved properties in terms of mechanical strength, acid resistance and high-temperature resistance for a low-cost composition. The invention also relates to a process for producing the said strands and to the composition allowing them to be produced.

Abstract: The invention relates to glass reinforcement strands, the composition of which comprises the following constituents in the limits defined below, expressed as percentages by weight: 58 to 63% SiO2; 10 to 16% Al2O3; 16 to 23% CaO; 0.5 to 3.5% MgO; 0 to 2% Na2O+K2O+Li2O; 1 to 1.5% TiO2; 0 to 1.5% B2O3; 0 to 0.4% Li2O; 0 to 0.4% ZnO; 0 to 1% MnO; and 0 to 0.5% F. These strands have improved properties in terms of mechanical strength, acid resistance and high-temperature resistance for a low-cost composition. The invention also relates to a process for producing the said strands and to the composition allowing them to be produced.

Abstract: The invention relates to glass reinforcing yams, the composition of which comprises the following constituents, within the limits defined below, expressed in percentages by weight: SiO2 50-65% Al2O3 12-20% CaO 13-16% MgO ?6-12% B2O3 0-3% TiO2 0-3% Na2O + K2O <2% F2 0-1% Fe2O3 <1. These yarns are made of a glass offering an excellent compromise between its mechanical properties represented by the specific Young's modulus and its melting and fiberizing conditions.

Abstract: Glass reinforcement strand, the composition of which comprises the following constituents, within the limits defined below, expressed as percentages by weight: SiO2 50 to 60%, preferably SiO2 ? 52% and/or SiO2 ? 57%; Al2O3 10 to 19%, preferably Al2O3 ? 13% and/or Al2O3 ? 17%; B2O3 16 to 25%; ZrO2 0.5 to 1.5%; Na2O ?1.5%, preferably Na2O ? 0.8%; K2O ?1.5%, preferably K2O ? 0.8%; R2O ?2%, preferably R2O ? 1%; CaO ?10%; MgO ?10%; F 0 to 2%; TiO2 0 to 3%; RO 4 to 15%, preferably RO ? 6% and/or RO ? 10%; and Various ?3%, where R2O = Na2O + K2O + Li2O, and RO = CaO + MgO. The dielectric properties of such glass compositions are particularly advantageous in the MHz and GHz ranges.

Abstract: Glass reinforcement yarn, the composition of which comprises the following constituents, in the limits defined below, expressed as percentages by weight: 1 SiO2 50 to 60%, preferably SiO2 ≧ 52% and/or SiO2 ≦ 57% Al2O3 10 to 19%, preferably Al2O3 ≧ 13% and/or Al2O3 ≦ 17% B2O3 16 to 25% P2O5 0.5 to 4% Na2O ≦ 1.5%, preferably Na2O ≦ 0.8% K2O ≦ 1.5%, preferably K2O ≦ 0.8% R2O ≦ 2%, preferably R2O ≦ 1% CaO ≦ 10% MgO ≦ 10% F ≦ 0 to 2% RO 4 to 15%, preferably RO ≧ 6% and/or RO ≦ 10% Various ≦ 3%, where R2O = Na2O + K2O + Li2O, and RO = CaO + MgO.

Abstract: The present invention relates to reinforcing glass yarns, the composition of which comprises the following constituents within the limits defined hereinbelow, expressed in percentages by weight:______________________________________ SiO.sub.2 58 to 62% Al.sub.2 O.sub.3 10 to 16% CaO more than 18% MgO more than 1.5% CaO + MgO less than 28% Na.sub.2 O + K.sub.2 O + Li.sub.2 O less than 2% TiO.sub.2 less than 1.5% Fe.sub.2 O.sub.3 less than 0.5% B.sub.2 O.sub.3 less than 2% F.sub.2 less than 2% ______________________________________this composition furthermore comprising less than 1% of other constituent(s) and comprising more than 0.5% of at least one of the three components F.sub.2, B.sub.2 O.sub.3 and Li.sub.2 O.These yarns have a composition providing an excellent compromise between its cost and its fiberizability.