Method of forming shaped hydrogel articles including contact lenses
US4889664A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 25, 1988 |
| Grant date | Dec 26, 1989 |
| Priority date | — |
| Expiry date | Nov 25, 2008 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB29K2995/0092
- WIPO fieldOther special machines
- WIPO sectorMechanical engineering
Abstract
Shaped hydrogel articles such as soft contact lenses are prepared by (1) molding or casting a polymerization mixture comprising: (a) a monomer mixture comprising a major proportion of a hydrophilic (meth)acrylate ester such as 2-hydroxyethyl methacrylate, and a cross-linking monomer; and (b) a water-displaceable diluent, wherein said diluent has a viscosity of at least 100 MPa Sec at 30.degree. C., and wherein said diluent consists essentially of a boric acid ester of certain dihydric alcohols, said dihydric alcohols having Hansen polar (.delta..sub.p) and Hansen hydrogen bonding (.delta..sub.h) cohesion parameters falling within the area of a circle defined as having a center at .delta..sub.h =20.5, .delta..sub.p =13, and a radius of 8.5, to produce a shaped gel of a coploymer of said monomers and said diluent, and (2) thereafter replacing said diluent with water.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.