Methods of deblocking, extracting and cleaning polymeric articles with supercritical fluids
AssigneeCiba-Geigy Corporation
InventorsRoger J. Hoffman, Wilson L. Terry, Jr.
Life of this patent
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Abstract
Methods of deblocking a polymeric article from a mold and/or removing undesirable materials from a polymeric article by applying supercritical fluids to the polymeric article. A preferred process is the treatment of ophthalmic lenses, such as contact lenses. Supercritical fluid, composed primarily of carbon dioxide, is applied to a contact lens affixed to a mold subsequent to the polymerization step. The application of supercritical fluid (SCF) causes the lens to efficiently and consistently separate from the mold, removes undesirable materials such as unreacted monomer, oligomers, or residual solvents from the lens core, and/or cleans the lens surface of adhered debris.
Claims18
A method of deblocking polymeric articles from molds, comprising the steps of:
- (1) providing a stream of supercritical fluid at a predetermined temperature and a predetermined pressure;
- (2) contacting a hydrophilic polymeric article with the supercritical fluid for a predetermined period of time in a manner such that the polymeric article is detached from a mold, wherein the contacting step is conducted without an extraneous agitation or with a mechanical agitation;
- and
- (3) removing the supercritical fluid from the polymeric article.
Dependencies are inferred from the claim text.