W. R. Grace Co.-conn.

E.i. Dupont De Nemours and Company

Daniel Ray Fruge

Demetrius Michos

Robert P Foss

Peter K Sysak

Composite inorganic particles and compositions containing silica particles are disclosed. Methods of making silica particles and methods of using composite inorganic particles are also disclosed.

Composite metal oxide particles and methods of making and using the same

A coating composition comprising low sodium containing colloidal silicas and ink jet recording sheets prepared from such coatings are described. The coating comprises binder and colloidal silica preferably having an average particle size in the range of about 1 to about 300 nanometers and which has a solids to alkali metal ratio of at least the sum of AW(&#x2212;0.013SSA+9), AW being the atomic weight of alkali metal present in the colloidal silica and SSA being the specific surface area of the silica. It has been discovered that if the alkali metal, e.g., sodium, content of colloidal silica is reduced, coatings prepared from such colloidal silica and applied to conventional ink jet recording sheet supports provide a specular gloss of at least 30 at 60&#xb0; C., even at a relatively high silica solids to binder solids ratio of 1:1 or greater.

Coating composition comprising colloidal silica and glossy ink jet recording sheets prepared therefrom

A coating composition comprising relatively low alkali cationic colloidal silicas and ink jet recording sheets prepared from such coatings is described. The coating comprises binder and cationic colloidal silica preferably having an average particle size in the range of about 1 to about 300 nanometers and which has a solids to alkali metal ratio of at least the sum of AW(&#x2212;0.013SSA+9), AW being the atomic weight of alkali metal present in the colloidal silica and SSA being the specific surface area of the silica. It has been discovered that if the alkali metal, e.g., sodium, content of colloidal silica is reduced, coatings prepared from such colloidal silica and applied to conventional ink jet recording sheet supports provide a specular gloss of at least 30 at 60&#xb0; C., even at a relatively high silica solids to binder solids ratio of 1:1 or greater.

A coating composition comprising cationic colloidal silicas and ink jet recording sheets prepared from such coatings is described. The coating comprises binder and polydispersed cationic colloidal silica. The cationic colloidal silica preferably has an average particle size in the range of about 1 to about 300 nanometers. It has been discovered that if a cationic polydispersed colloidal silica is employed in a glossy coating formulation, the coating provides a specular gloss of at least 30 at 60&#xb0; C., even at a relatively high silica solids to binder solids ratio of 1:1 or greater, but also a coating having good to excellent printability characteristics.

A coating composition comprising a relatively low alkali-containing colloidal silica and glossy ink jet recording sheets prepared from such coatings is described. The coating comprises binder and colloidal silica, e.g., having an average particle size in the range of about 1 to about 300 nanometers. The low alkali colloidal silica of this invention comprises ammonia, polydispersed colloidal silica, or both. Polydispersed silicas having a particle size distribution such that the median particle size is in the range of 15 to 100 nanometers and 80% of the particles span a range of at least about 30 to about 70 nanometers are preferred. It has been discovered that coatings prepared from such colloidal silica and applied to conventional ink jet recording sheet supports have a specular gloss of at least 30 at 60&#xb0; C., and excellent printability at silica solids to binder solids ratio of 1:1 or greater.

A storage stable and rapid dissolving packaged powder developer of uniform composition is produced by preparing developer or developer precursor solutions and removing solvent to provide powder for packaging in plastic impervious to the atmosphere. Preferably, the solvent is removed by freeze-drying or spray-drying.

Powdered packaged developer

Sharper edges are obtained in silver halide wash-off films for tanning development when from 5 to 60% of the unhardened gelatin binder in one or more layers is replaced with a synthetic amphoteric polymer consisting essentially of at least one of each of three constituents: (a) carboxylic acid, (b) alkyl primary amine, and (c) secondary and/or tertiary amine, the amphoteric polymer having an isoelectric point of from 4 to 8.

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Wilmington, DE, United States of America

Daniel Ray Fruge