The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 20, 1976
Filed:
Nov. 28, 1973
John Charles Gebhard, Jr, West Chester, PA (US);
Marion Glen Waggoner, Parkersburg, WV (US);
James Lang Webster, Parkersburg, WV (US);
E. I. Du Pont de Nemours and Company, Wilmington, DE (US);
Abstract
Method whereby spherical-shaped copolymer particles having a rough surface are produced. In a closed shear zone of a shear device under positive pressure water, at least 0.6% by weight of ammonia, and up to 50% by weight of copolymers of alpha-olefins and alpha, beta-ethylenically unsaturated carboxylic acids having from 3 to 8 carbon atoms, and optionally an additional monoethylenically unsaturated monomer, the copolymer having from 0% to 90% of the carboxylic acid groups ionized by neutralization with metal ions, are sheared at a temperature above the melting point but below the thermal degradation point of the copolymer to form a homogeneous aqueous slurry wherein the copolymer particles have an average particle size of less than 100 microns. The slurry is maintained with agitation at a temperature above the copolymer melting point for at least 0.5 minute until substantially all the copolymer particles become spherical. Agitation is continued and the slurry is cooled to a temperature below about the copolymer freezing point over a period of at least 0.3 minute while the pressure is maintained at sufficient level to keep the water in the liquid state. The pressure of the cooled slurry is reduced to atmospheric pressure and the copolymer particles are separated from the aqueous component of the slurry. The spherical-shaped particles have an average diameter of 10 to 100 microns and the surface thereof is covered with hemispherical shaped bumps about 0.1 micron in diameter. The particles form a free-flowing powder useful in preparing clear, protective, shatter-resistant coatings for glass, and protective coatings for metals and other materials.