Molded plastic parts, particularly spin-cast plastic parts for eyeglass frames
AssigneeUniversal Optical Company, Inc.
InventorsIrving J. Arons, Richard E. Merrill, Arthur P. Drennan
Life of this patent
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Abstract
Disclosed are molded plastic parts particularly eyeglass frame components, the centrifugal spin-casting of such parts and mold apparatus for producing such parts. Also disclosed are flexible molds for spin-casting eyeglass fronts and temples. In accordance with one aspect of the invention, the plastic parts are made from a resin system or mixture in liquid form comprising an epoxy resin, a curing agent therefore and an ultra-violet absorber and/or an antioxidant. DGEBA-type epoxy resins and polyoxypropylenediamine curing agents are the disclosed preferred epoxy resin and curing agent.
Claims13
A spin casting process for producing a solid, substantially clear, low color thermoset plastic part which has a cross-linked structure when cured, particularly an eyeglass part, in a flexible mold from a curable liquid resin system, the flexible mold including separable mold portions at least one of which is flexible and which define at least one mold cavity when the mold portions are assembled to form the flexible mold, means being provided for rigidly holding the mold portions together as a rigid, transportable mold assembly, said process comprising the steps of:
- assembling the mold portions to form the flexible mold;
- introducing the liquid resin system comprising an epoxy resin and a curing agent therefor which are substantially clear and of low color into the flexible mold;
- rotating the flexible mold in the rigid mold assembly in or on spinning apparatus until the liquid resin system is distributed in the mold cavity but is still soft and uncured and is yet not self-supporting;
- removing the rigid mold assembly including the flexible mold as a rigid unit from the spinning apparatus while the liquid resin system therein is still soft and uncured and is yet not self-supporting;
- hardening the liquid resin system while in the rigid mold assembly after removal of the rigid mold assembly from the spinning apparatus to form the part;
- and
- thereafter disassembling the rigid mold assembly and removing the part.
A spin casting process for producing a solid thermoset plastic part which has a cross-linked structure when cured, particularly an eyeglass part, in a flexible mold from a curable liquid resin system, the flexible mold including separable mold portions at least one of which is flexible and which define at least one mold cavity when the mold portions are assembled to form the flexible mold, means being provided for rigidly holding the mold portions together as a rigid, transportable mold assembly, said process comprising the steps of:
- assembling the mold portions to form the flexible mold;
- introducing the liquid resin system into the flexible mold;
- rotating the flexible mold in the rigid mold assembly in or on spinning apparatus until the liquid resin system is distributed in the mold cavity but is still soft and uncured and is yet not self-supporting;
- removing the rigid mold assembly including the flexible mold as a unit from the spinning apparatus while the liquid resin system therein is still soft and uncured and is yet not self-supporting;
- hardening the liquid resin system while in the rigid mold assembly after removal of the rigid mold assembly from the spinning apparatus to form the part;
- and
- thereafter disassembling the rigid mold assembly and removing the part.
Dependencies are inferred from the claim text.