Low alkali, non-crystalline, vitreous silica fillers
First Claim
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1. A white brightness powder for use in filler and extender applications comprising a finely ground vitreous calcium aumino-silicate (CaO—
- Al2O3—
SiO2) powder derived from previously discarded glass fibers having low alkali and low iron content and low levels of discolorants;
said powder having an alkali content by weight of not more than 2% as (Na2O+K2O), an iron content by weight of not more than 0.8% as Fe2O3 and being white in color with a reflectance value of at least 80 as measured by a Technibrite TB-1C colorimeter according to the ISO 2467, 2471 method;
at least 95% by weight of the powder comprising particles of less than 45 microns E.S.D. and said particles having a blocky, equi-dimensional particle shape wherein the average aspect ratio of the particles is less than 2;
1, and with substantially no residual high aspect ratio fibers.
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Abstract
A substantially white powder for use as a filler and/or extender derived from by-products of manufacturing vitreous low alkali, low iron glass fibers, and a method for producing the powder. The filler has very low alkalinity and by virtue of its being essentially free of crystalline silica is non-hazardous to health and therefore safe for consumer-based and industrial-based uses.
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Citations
5 Claims
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1. A white brightness powder for use in filler and extender applications comprising a finely ground vitreous calcium aumino-silicate (CaO—
- Al2O3—
SiO2) powder derived from previously discarded glass fibers having low alkali and low iron content and low levels of discolorants;
said powder having an alkali content by weight of not more than 2% as (Na2O+K2O), an iron content by weight of not more than 0.8% as Fe2O3 and being white in color with a reflectance value of at least 80 as measured by a Technibrite TB-1C colorimeter according to the ISO 2467, 2471 method;
at least 95% by weight of the powder comprising particles of less than 45 microns E.S.D. and said particles having a blocky, equi-dimensional particle shape wherein the average aspect ratio of the particles is less than 2;
1, and with substantially no residual high aspect ratio fibers. - View Dependent Claims (2, 3, 4, 5)
- Al2O3—
Specification