Acicular, crystalline calcium metaphosphate
AssigneeMonsanto Company
InventorEdward J. Griffith
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Abstract
Acicular, crystalline calcium metaphosphate having a length to average diameter ratio of at least 10:1 can be prepared by forming a melt of materials used as a source of calcium, phosphorus and alkali metal, cooling the melt to about 550.degree. C. to about 970.degree. C., inducing acicular crystal formation, and recovering the acicular crystals. The diameters of the resultant acicular, crystalline calcium metaphosphates can average as small as 0.5 micron or smaller. Acicular, crystalline calcium metaphosphate can also be prepared with an average diameter of several microns and a length of several centimeters. Such acicular, crystalline calcium metaphosphates are useful in a number of applications, and particularly to prepare composites with organic polymeric materials.
Claims26
A method for producing acicular, crystalline calcium metaphosphate which comprises:
- (a) forming a melt source of calcium, phosphorus, oxygen and alkali metal wherein the melt contains from about 2 mole percent to about 20 mole percent M.sub.2 O, where M is alkali metal, from about 48 mole percent to about 58 mole percent P.sub.2 O.sub.5 and from about 27 mole percent to about 48 mole percent CaO;
- (b) cooling the melt to about 550.degree. C. to about 970.degree. C.;
- (c) inducing acicular crystal formation;
- and
- (d) recovering the acicular crystals.
Acicular, crystalline calcium metaphosphate having an aspect ratio of at least 10:1.
Crystalline calcium metaphosphate wherein at least 25 weight percent of the crystals are acicular and having an aspect ratio of at least 10:1.
A composite which comprises from about 1 to about 99 percent by weight acicular crystalline calcium metaphosphate having an aspect ratio of at least 10:1, and from 1 to about 99 percent by weight organic polymeric material.
Dependencies are inferred from the claim text.