Glass compositions

US4014705A · kind A · utility

Assignee

• Pilkington Brothers Limited · GB

Inventor

• Brian Yale

Key dates

• Filing date: Dec 23, 1974
• Grant date: Mar 29, 1977
• Expiry date: Dec 23, 1994

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C03C13/002
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Alkali-resistant continuously-drawn glass fibers, for use in the reinforcement of cement products, are composed of SiO.sub.2 67 to 82 mol.%, ZrO.sub.2 7 to 10 mol.%, R.sub.2 O 9 to 22.5 mol.% (where R = Na, up to 5 mol.% of which may be replaced by Li or K), F.sub.2 3 to 9 mol.% and Al.sub.2 O.sub.3 (computed as AlO.sub.1.5) 0 to 5 mol.%, the permissible maximum value of the total of SiO.sub.2 + ZrO.sub.2 + AlO.sub.1.5 being on a sliding scale dependent on the content of ZrO.sub.2 and ranging (when F.sub.2 = 9 mol.%) from 89 mol.% when ZrO.sub.2 is 7 mol.% down to 87 mol.% when ZrO.sub.2 is 10 mol.%, the said maximum value being reduced by a further 5 mol.% over the whole scale when F.sub.2 = 3 mol.%. The fiberizing temperature is below 1350.degree. C and the liquidus temperature is at least 40.degree. C below the fiberizing temperature. Preferably, to ensure that the fiberizing temperature is below 1320.degree. C, the said maximum value of SiO.sub.2 + ZrO.sub.2 + AlO.sub.1.5 is further reduced by 1 mol.% over the whole scale.