Color-stable superabsorbent polymer composition
Patent #: 7,528,291
Inventor(s): Norbert Herfert, Michael Azad and Peter Carrico
Company: BASF Aktiengesellschaft
A method of manufacturing color-stable superabsorbent polymer particles has been issued a patent. The process includes forming a monomer mixture comprising at least one monomer capable of forming a superabsorbent polymer, a crosslinking agent, an initiator system that contains 0 to 300 ppm of a persulfate, a photoinitiator and, optionally, water. The next step in the process is polymerizing the monomer and the crosslinking agent in the monomer mixture to form a superabsorbent polymer hydrogel with a water content of 25 weight % or less and then subjecting the superabsorbent polymer hydrogel to a UV radiation of 2000 milliwatt/cm2 or less. The next step is to comminute the superabsorbent polymer hydrogel to provide superabsorbent hydrogel particles and then dry the superabsorbent polymer hydrogel particles for a sufficient time at a sufficient temperature to provide the color-stable superabsorbent polymer particles.
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