High throughput process for reactive extrusion of epoxy resin

Abstract

The present invention provides low cost resins (e.g., advanced epoxy resins), processes for making these resins, and coatings made with theses resins. Specifically, the present invention provides high throughput extrusion processing of advanced epoxy resins using an appropriate amount of an iminium salt catalyst. Preferred iminium salt catalysts are stable at room temperature in the reaction mixture (thereby enabling the pre-mixing of ingredients and the stable storage of the pre-mixed ingredients) and yet are highly efficient at the processing temperatures described herein. An example of one such advance epoxy resin is the reaction product of diglycidyl ether of bisphenol A with bisphenol A in the presence of an iminium salt catalyst. Preferred processes are performed using no solvent or only negligible amounts of solvent. One preferred extrusion process utilizes an intermeshing co-rotating twin-screw extruder, however, other types of extruders may alternatively be employed.

Description

FIELD The present invention relates to the high throughput extrusion processing of advanced epoxy resins and coating compositions containing same. BACKGROUND Packaging coatings (e.g., for the interior of beverage cans and the like) previously have been formulated from advanced epoxy resins. For such purposes, it is desirable for the coating composition to have both good dry adhesion and wet adhesion properties. Traditionally, batch processes have been used for the preparation of advanced epoxy resins. Unfortunately, however, these processes are expensive. They also unfortunately require the use of large amounts of solvent that poses manufacturing and potential environmental concerns. Attempts have been made previously to process advanced epoxy resins using extruders. U.S. Pat. Nos. 4,612,156 and 5,310,854 describe two such attempts. Unfortunately, however, the methods disclosed in these patents have been found to yield inefficient throughput and, hence, are expensive to operate....

AI Technical Summary

Problems solved by technology

Unfortunately, however, these processes are expensive.

They also unfortunately require the use of large amounts of solvent that poses manufacturing and potential environmental concerns.

Unfortunately, however, the methods disclosed in these patents have been found to yield inefficient throughput and, hence, are expensive to operate.

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