Abstract: A cartridge for use in a mixing, dispensing and purging apparatus of mutually reactive chemicals. The cartridge comprises a mixing assembly and purging rod. The mixing assembly includes a core member that is preferably deformable with an axial bore formed in it through which the purging rod reciprocates. The mixing assembly also includes a scraper assembly positioned within the mixing assembly. The scraper assembly includes two cup-shaped members positioned essentially in mirror image with each cup-shaped member including an aperture in its base through which the purging rod extends. An insert is positioned within both of the cup-shaped members and extends between the base of each cup-shaped members. The cup-shaped members and insert are designed to remove material built up on the reciprocating purging rod while keeping the rod aligned and preventing fluid flow through the scraper assembly. The scraper assembly thus alleviates the need for any solvent material.

Abstract: A mixing, dispensing and purging apparatus for mutually reactive chemicals. The dispensing apparatus includes a cartridge comprising a mixing assembly and purging rod. The mixing assembly having a block of inexpensive monolithic design with an axial bore formed in it through which the purging rod reciprocates. The mixing assembly also includes a scraper assembly positioned within the block of material. The scraper assembly includes two cup-shaped members positioned essentially in mirror image with each cup-shaped member including an aperture in its base through which the purging rod extends. An insert is positioned within both of the cup-shaped members and extends between the base of each cup-shaped members. The cup-shaped members and insert are designed to remove material built up on the reciprocating purging rod while keeping the rod aligned and preventing fluid flow through the scraper assembly. The scraper assembly thus alleviates the need for any solvent material.

Abstract: A prepolymerization step prior to casting reduces shrinkage during polymerization of a composition containing diethylene glycol bis(allyl carbonate) with up to 40% of a vinyl ester, preferably vinyl acetate, and one or more free radical type initiators. The prepolymerization step includes adding a small amount of free radical type initiator, which may be the same or different than that used just prior to casting, and heating to a temperature higher than one hour half-lifetime temperature of the initiator. In this manner, most of the added initiator is consumed and the prepolymerization produces the highest possible conversion while preventing overpolymerization. High yield of lenses of ophthalmic quality is obtained.

Abstract: A method of minimizing distortion and preventing wrinkles in optical plastic-glass composites utilizing a lens-laminating mechanism wherein stretched synthetic fabric is disposed between a plunger and the plastic-glass composite wherein the stretched synthetic fabric transfers some of the plunger forces toward the perimeter of the plastic-glass composite during contact of the plunger with the composite.

Abstract: Finished and semi-finished ophthalmic lenses are made by polymerizing the monomer while it is sealed in an oxygen-impermeable envelope.

Abstract: A device to prevent optical distortion in glass-plastic composite lenses comprising an open outer ring having adjusting means, an inner ring held by the outer ring, and an elastic material in stretched position covering the inner ring and held in stretched position by a force exerted on the outer ring by the tightening of the adjusting means.

Abstract: Disclosed, in a method for preparing a preformed thermoplastic/thermoset wafer for lamination to a prefinished ophthalmic lens, the improvement comprising: storing the preformed thermoplastic/thermoset wafer immediately after manufacture under refrigerating conditions; and subjecting said stored wafer to a temperature of 90.degree. to 120.degree. F. at 50% to 70% RH for no more than 48 hours just prior to lamination of same to an ophthalmic lens.