Ashland Oil, Inc. v. Delta Resins & Refractories, Inc.

Opinion

 [***657]  [*283]   KASHIWA, Circuit Judge.

Ashland Oil, Inc. (Ashland) appeals from the judgment of the United States District Court for the Eastern District of Michigan, Southern Division, 587 F. Supp. 1406 (1984), holding claims 1, 2, 7 and 10 of U.S. Patent No. 3,485,797 (the '797 patent), claims 14 and 19 of U.S. Patent No. 3,409,579 (the '579 patent), and claim 17 of U.S. Patent No. 3,676,392 (the '392 patent) invalid under 35 U.S.C. § 103. We reverse the remand.

Background 

Ashland is the assignee of the three patents involved in this case, which were issued to Dr. Janis Robins. These patents are directed to certain chemical products and processes finding ultimate use in the  [*284]  foundry industry. One method of forming metal castings [**2]  in the foundry industry involves compacting sand around a pattern to form a sand mold, removing the pattern, and then pouring molten metal into the sand mold. This process often involves the use of internal sand cores around which the molten metal flows to produce various internal configurations.

A chemical binder, for example a phenolic urethane formed by reacting a phenol-formaldehyde resin with a hardener component, such as a polyisocyanate, and a curing agent, such as a tertiary amine, is mixed with the sand, causing the sand-binder mixture to harden at a predetermined rate. After the sand mold mixture has hardened, the mixture retains its shape during the pouring of the molten metal. After the metal solidifies the binder must break down to permit the sand to be readily dislodged from the casting.

An optimized sand-binder mixture should have a slow or negligible curing period after the initial mixing of the binder with the sand, i.e., the work time, followed by a period of rapid curing. During the work time, the sand-binder mixture remains flowable, due to negligible curing or hardening, to allow easy forming of the mixture to conform to the pattern. Rapid curing after [**3]  the mold has been formed allows the sand-binder mixture to rapidly reach its hardened state, thus permitting initiation of molten metal pouring.

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