Comment license (Score 1) 2
Plan A: Ask for a perpetual non-exclusive license to the copyrights you create where the work is a general-purpose utility not directly related to the products and services the company provides. Tell the boss straight up that you'd like to refine some of those utilities into products on your own time and then sell them. Agree that the company will retain a perpetual non-exclusive license to any products you produce during your employment which made use of the work you built for the company.
Plan B: Request permission to release the utilities into the public domain. Consume and refine the software on your own time, selling the result. The result, with the productization additions unnecessary for your primary work is covered by your copyright. Anyone could but no one will go back to the public domain work and build back up.