Epoxy resin composition
AssigneeShell Oil Company
InventorEdward J. Marx
Life of this patent
Estimating the term…
Abstract
A solid epoxy resin having a broad molecular weight distribution is prepared by melt or solution blending a major portion of a normally-solid epoxy resin having a weight per epoxide of about 1500 to about 10,000 and a minor portion of a normally-liquid epoxy resin having a weight per epoxide of from about 180 to about 340, and solidifying the resulting blend. A solvent-free powder coating composition is prepared by combining the blend with an effective amount of a curing agent and reducing the epoxy resin/curing agent to an average particle size less than about 60 mesh. The epoxy blend permits preparation of a powder coating formulation having improved grinding properties.
Claims16
A solid, solvent-free powder coating composition comprising (a) a product of blending from about 75 to about 95 weight percent, based on the weight of the epoxy blend, of a normally-solid epoxy resin having a weight per epoxide within the range of about 1500 to about 10,000, and from about 25 to about 5 weight percent of a normally-liquid epoxy resin having a weight per epoxide in the range of about 175 to about 350, and (b) an effective amount of a curing agent for the epoxy blend.
A method for preparing a solid epoxy resin powder coating composition comprising the steps of:
- (a) melt-blending from about 75 to about 95 weight percent, based on the weight of the epoxy components of the melt-blend, of a normally-solid epoxy resin which is a glycidyl polyether of 2,2-bis(4-hydroxyphenyl)propane having a weight per epoxide within the range of about 1500 to about 10,000, and a normally-liquid epoxy resin which is a polyglycidyl polyether of 2,2-bis(4-hydroxyphenyl)propane having a weight per epoxide within the range of about 175 to about 350;
- and
- (b) cooling the resulting epoxy blend to a temperature below the melting point of the epoxy blend, thereby solidifying the epoxy blend;
- (c) combining the solidified epoxy blend with an effective amount of a curing agent;
- and
- (d) reducing the epoxy blend/curing agent to a powder having an average particle size less than about 60 mesh.
Dependencies are inferred from the claim text.