Abstract:
An extrusion-compression molding process is provided for making optical articles wherein a melt shot of optical polymer extrudate is fed to sequentially moving lower dies of a die set including a lower die and an upper die and then the upper die positioned on top of the melt shot containing lower die and the die set compressed forming the optical article. After the optical article is formed, the lower die and upper die are separated and recycled for forming additional optical articles. The optical polymeric material may be in the form of pellets and melted in an extruder. A reaction extruder may also be employed where the optical polymeric material is produced in the reaction extruder from optical polymer monomers. A shuttle carriage is preferably used to transport the lower die, melt shot containing lower die and melt shot containing die set through the steps of the molding process. A control system is used to obtain input data and generate output signals to monitor and control the process steps.
Abstract:
A method of continuously fabricating a lens excellent in various optical characteristics and having no nonuniformity in the characteristics over a total of the lens and a lens fabricated by the method. A first step for forming thiourethane prepolymer and a second step for making thiourethane prepolymer react with at least one urethane forming monomer are carried out in an extruder or in a reactor having an extruding device at a succeeding step, extruded thermoplastic thiourethane-urethane copolymer for optical use is elongated in a sheet-like shape, a lens precursor is formed by punching out the copolymer elongated in a sheet-like shape and the lens precursor is pressed such that a predetermined curved face is provided at least on one face of the lens precursor.
Abstract:
A process for making thermoplastic thiourethane-urethane copolymers for use in making optical products preferably comprising reacting an aliphatic diisocyanate with a dithiol under polymerization conditions to form a thiourethane prepolymer which is then reacted with a diisocyanate such as methylene bis(phenyl isocyanate) and a polyol such as a diaromatic containing diol such as ethoxylated Bisphenol A or an aliphatic isocyanate reactive monomer such as tricyclodecane dimethanol or 1,4-dimethanol cyclohexane to form the copolymer product. The polymers have a combination of high refractive index and high Abbe No. The polymers also have high impact strength, high hardness and Tg's above 100.degree. C. It is preferred to make the polymer in an extruder.
Abstract:
A monomer composition characterized by being curable to form a resin suitable for optical products having a balanced refractive index and Abbe's number range and good tintability comprising a polyene monomer; a polyisocyanate, polyisothiocyanate, or an isocyanate monomer containing at least one isothiocyanate group; and a monomer having two or more active hydrogen groups such as polythiols, polyamines, and polyols. The invention also provides a special process for making the composition and for curing the composition to form a resin product.
Abstract:
A monomer composition characterized by being curable to form a resin suitable for optical products having a balanced refractive index and Abbe's number range and good tintability comprising a polyene monomer; and polyisocyanate, polyisothiocyanate, or an isocyanate monomer containing at least one isothiocyanate group; and a monomer having two or more active hydrogen groups such as polythiols, polyamines, and polyols. The invention also provides a special process for making the composition and for curing the composition to form a resin product.