US Patent 7241818 Filler comprising fly ash for use in composites

The present invention is a fly ash filler or filler blend having a particle size distribution with at least three modes that can be combined with a polymer or bitumen at higher filler loadings to produce a filled polymer or bitumen for composites that, in many cases, can produce improved mechanical properties for the composites over composites using conventional fillers. As a result, superior composites (e.g. those used in carpet backing) can be produced at a lower cost than conventional composites. The present invention also includes a method for producing a composite, comprising the steps of combining a polymer or bitumen with a fly ash filler or a filler blend having a particle size distribution with at least three modes to produce a filled polymer or bitumen and producing a composite with the resulting filled polymer or bitumen. The present invention further includes a method of determining what fly ashes can be used as fillers for composites.