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US 4,904,749 AGranted
Preparation of PHEMA by precipitation/suspension polymerization
AssigneeMarion Laboratories, Inc.
InventorsPhyllis L. Brusky, Richard A. Markle
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AssigneeMarion Laboratories, Inc.
InventorsPhyllis L. Brusky, Richard A. Markle
Estimating the term…
Disclosed is a method for preparing poly(2-hydroxyethyl methacrylate) polymers (PHEMA) by a precipitation/suspension polymerization technique wherein a reaction mixture comprising hydroxyethyl methacrylate monomer (HEMA), solvent, and a free-radical initiator is subjected to heating for a time adequate for said PHEMA to be formed. The improvement in process of the present invention comprises restricting said HEMA to contain less than about 0.5 wt-% polyfunctional acrylate content, incorporating a suspending agent in said reaction mixture, agitating said reaction mixture during said heating, and restricting said solvent to one having a solubility parameter of between about 7.5 and 9, to produce PHEMA polymer particles ranging in size from about 30 to 1,000 microns and having a molecular weight ranging from about 500,000 to 2,000,000.
In a method for preparing poly(hydroxyethyl methacrylate) (PHEMA) particles by precipitation/suspension polymerization wherein a reaction mixture comprising hydroxyethyl methacrylate (HEMA), a solvent, and a freeradical initiator is subjected to heating for a time adequate for said PHEMA particles to be formed, the improvement which comprises:
Dependencies are inferred from the claim text.