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AssigneeAkron Polymer Systems, Inc.
InventorsYufeng Zhu, Lang Hu, Zhen Li, Limin Sun, Dong Zhang, Xiaoliang Zheng
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This invention discloses a method for extending the shelf life of polyamic ester (PAE) solutions during the manufacturing of positive-type photosensitive polyimide (PSPI) precursor resins. With the addition of certain acids within a specified loading range to the reaction solution after the acetal esterification reaction, the shelf of the PAE solution can be significantly increased by decreasing the rate of imidization. The acid additive may consume part or all of the impurities generated from the acetal esterification reaction, which improves the stability of the PAE polymer. This invention substantially improves the feasibility and manufacturing cost of positive-type PSPI precursor polymers.
A method to extend the shelf life of polyamic ester (PAE) solutions prepared from the esterification of a polyamic acid (PAA) in solution with an acetal by slowing down the imidization rate through the addition of an acid or acids that have a pKa(1) less than 2.1 and a loading range between 1 mol %-100 mol % based on the charged amount of acetal.
Dependencies are inferred from the claim text.