Water based coating for roughened metal surfaces
AssigneeAshland Oil, Inc.
InventorsRoger E. Hayner, Stephen E. See
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Abstract
Calcium or other sulfonate gel in an oil carrier (such as that of U.S. Pat. No. 4,629,753 to Quinn), optionally mixed with a small amount of sodium sulfonate and tall oil fatty acids, can be neutralized with amine, e.g. DMEA, to form a soap which can be dispersed in water. Adding an acrylic emulsion results in an acrylic coating rich in corrosion-retarding alkali metal or alkaline earth metal sulfonates. This finish on metalurgically roughened, e.g. nitrocarburized, metal forms a firm film which can resist greater than 500 hours ASTM B117 salt spray.
Claims9
A method for protecting metallic workpieces from corrosion, comprising in combination the steps of:
- A. roughening the surfaces of said work pieces by sandblasting, oxynitriding, nitrocarburizing, nitrocarburizing plus oxidizing, phosphating or other metallurgical process to provide an expanded porous surface, and
- B. applying to said expanded surface a waterborne corrosion protective coating composition capable of application to metallic surfaces;
- said composition comprising in combination:
- 1. colloidal metal-bearing organic/inorganic non-Newtonian complex having a total base number in the range of from about 80 to about 400 and comprising solid metal-containing colloidal particles, liquid dispersing agent and an organic molecule containing a hydrophobic portion and a polar substituent;
- 2. a fatty acid having an acid value in the range of about 80 to about 250, and saponification number in the range of from about 80 to about 250, and having an iodine number in the range of about 110 to 160.
- 3. alkali substituted organic amine.
- 4. film-forming organic polymer.
Dependencies are inferred from the claim text.