KPR
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 KPR facts

• Once dried KPR can be dissolved by several solvents but after exposure to strong ultraviolet light it hardens and becomes insoluble by some of these solvents
• It is also resistant to acid, ferric chloride and other chemicals used to etch metals
• The fundamental method of its use was first described in two US Patents, USP 2610120 and USP 2670287, assigned to the Eastman Kodak Company of Rochester, New York
• These photo-resistant resins were formed of cinnamic acid esters with the most preferable being polyvinyl cinnamate
• While they were developed primarily for photolithography for high-speed print setting for uses such as newspaper printing, their perhaps highest value came from their ability to produce non-conducting layers on top of conducting layers to precise dimensions
• This enabled the "printing" of large scale, closely placed conductive and non-conductive pathways to create binary gates
• These were semi-conductors or the means to create semiconductors
• This technology was utilized heavily by the Shockley 8, at the original Fairchild Semiconductor to produce more and more closely spaced semiconductors for computing
• It is ironic that Kodak, the original patent assignee, did not really participate in the economic juggernaut that it created through this lithographic printing technology