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:
Sep. 05, 2000
Filed:
Mar. 27, 1997
Richard Vicari, Corpus Christi, TX (US);
Olan Stanley Fruchey, Corpus Christi, TX (US);
Kathleen Nelson Juneau, Corpus Christi, TX (US);
Shelby Freland Thames, Hattiesburg, MS (US);
James Wayne Rawlins, Hattiesburg, MS (US);
Herberts GmbH, Cologne, DE;
Abstract
Novel powder coating compositions containing reactive hyperbranched polymers are disclosed and claimed. Preferred embodiments include powder coating compositions formed from hyperbranched polyesters having terminal hydroxy, carboxy, epoxy, and isocyanate groups. Preferred hyperbranched polyesters are formed from .alpha.,.alpha.-bis-(hydroxymethyl)-propionic acid, which act either as crosslinkers, adhesion promotors, or flow and leveling agents. A process for the synthesis of powder coating compositions is also disclosed which involves (a) self condensation of one or more of the multifunctional monomers to form the hyperbranched polymer, optionally, in the presence of suitable reactive end-capping moieties which are described herein; (b) melt blending of the hyperbranched polymer with suitable amounts of one or more of polyesters, epoxy resins, blocked urethane resins, or acrylic resins, a crosslinker, and one or more of suitable additional ingredients including degassers or flow and leveling agents, to form a flake; and (c) grinding and sieving of the flake to form the powder coating composition. These compositions exhibit improved flow and curing properties. These compositions can therefore be formed into thin films and can be cured at low temperatures to form smooth surfaces. Additionally, these films are hard and exhibit enhanced impact resistance properties than the conventional polyester resins. Thus, these powder coating compositions find utilities in automotive, packaging, and appliances.