nic acid (∼200 mol %). Considerable rate acceleration of benzylation, allylation, and p-nitrobenzylation was observed as compared to the reactions with less than 100 mol % of the acid catalyst. The triazine-based leaving group showed superior p-nitrobenzylation yield and stability in comparison to common leaving groups, trichloroacetimidate and bromide. A plausible reaction mechanism (the cationic
Novel crosslink agents are described that provide for the copolymerization of at least one hydrophilic monomer with at least one lens monomer typically used to prepare materials for ophthalmic lenses. The new crosslink agents have a relatively high selectivity for the hydrophilic monomer and limited reactivity with the crosslink agent used to polymerize the lens monomer.
Crosslink agents used to copolymerize at least one hydrophilic monomer with at least one lens monomer typically used to prepare polymeric materials for ophthalmic lenses. The crosslink agents have a relatively high selectivity for the hydrophilic monomer and limited reactivity with the crosslink agent used to polymerize the lens monomer. Accordingly, the invention is also directed to a hydrophilic crosslinked polymer that comprises at least two monomeric units and at least two different crosslink units. The use of the dual crosslink system provides an improved means to control the final chemical, physical and structural characteristics of the resulting polymer.
A contact lens made from a copolymer prepared from a monomer mixture comprising perfluorooctylethyloxyalkylene (meth)acrylate, siloxanyl (meth)acrylate, alkyl methacrylate, a hydrophilic monomer, and a crosslinking agent as the indispensable components. This lens has good oxygen-permeability, hardness, and wettability with water, thus being quite useful practically.
The present invention relates to a soft intraocular lens consisting of a copolymer formed from a perfluorooctylethyloxypropylene (meth)acrylate monomer, a 2-phenylethyl (meth)acrylate monomer, an alkyl (meth)acrylate monomer and a crosslinking monomer as essential components. The soft intraocular lens restores its original shape to stabilize itself in a proper period of time, e.g., approximately 20 ∼ 60 seconds, without remaining folded or self-adhering in its optical portion when folded to a small size, inserted into the eye while being held in a folded state and then released from a folding force.