Patent ID: 6949483

Claim:
A product comprising man-made vitreous fibres formed of a composition which includes, by weight of oxides, SiO 2 32 to 48% Al 2 O 3 18 to 30% CaO 10 to 30% MgO 2 to 20% FeO 2 to 15% Na 2 O + K 2 O 0 to 10% TiO 2 0 to 6% SiO 2 + Al 2 O 3 below 68% Other Elements 0 to below 8% wherein the composition has a viscosity at 1400° C. of 12 to 70 poise, and wherein the fibres have a dissolution rate of at least 20 nm per day when measured at a pH of 4.5.