Patent classifications
B29C2045/562
Method for injection molding weld line free minus power lens elements
A method for injection molding of a weld line free minus power lens element comprises injecting a melt of thermoplastic material at a temperature higher than a glass transition temperature (Tg) of the thermoplastic material in an initial molding cavity delimited by two facing mold inserts, wherein the melt of thermoplastic material comprises at least one UV absorber. During the injecting, the two facing mold inserts are moved toward one another to define a final molding cavity whose volume is less than that of the initial molding cavity. After cooling and disassembling of the two facing mold inserts, the weld line free minus power lens element is recovered. One of the two facing mold inserts comprises a flat surface facing the initial molding cavity, thereby to form a flat surface on one side of the weld line free minus power lens element. The other of the two facing mold inserts comprises a convex surface facing the initial molding cavity, thereby to form a concave surface on an opposite side of the weld line free minus power lens element.
Process for manufacturing composite articles
The present invention relates to the use of thermoplastic polymer compositions for impregnating reinforcing materials in the form of fabric or industrial fabrics for the manufacture of composite materials. The field of the invention is that of composite materials as well as molding/consolidation processes and obtained parts. The invention more particularly relates to a method of manufacturing a composite article by injection molding comprising at least the steps of introducing at least one reinforcement fabric into a preheated mold, partial closure of the mold, a temperature rise step of the mold, optionally a step of maintaining the temperature of the mold before injection of a thermoplastic polymer composition, a step of injecting a thermoplastic polymer composition into the mold, a step of mold closure to the final part thickness allowing the flow of the resin through the reinforcing fabric, a cooling step and a recovery step of the obtained composite article.
PROCESS FOR MANUFACTURING COMPOSITE ARTICLES
The present invention relates to the use of thermoplastic polymer compositions for impregnating reinforcing materials in the form of fabric or industrial fabrics for the manufacture of composite materials. The field of the invention is that of composite materials as well as molding/consolidation processes and obtained parts. The invention more particularly relates to a method of manufacturing a composite article by injection molding comprising at least the steps of introducing at least one reinforcement fabric into a preheated mold, partial closure of the mold, a temperature rise step of the mold, optionally a step of maintaining the temperature of the mold before injection of a thermoplastic polymer composition, a step of injecting a thermoplastic polymer composition into the mold, a step of mold closure to the final part thickness allowing the flow of the resin through the reinforcing fabric, a cooling step and a recovery step of the obtained composite article.
METHOD FOR INJECTION MOLDING WELD LINE FREE MINUS POWER LENS ELEMENTS
A method for injection molding of a weld line free minus power lens element comprises injecting a melt of thermoplastic material at a temperature higher than a glass transition temperature (Tg) of the thermoplastic material in an initial molding cavity delimited by two facing mold inserts, wherein the melt of thermoplastic material comprises at least one UV absorber. During the injecting, the two facing mold inserts are moved toward one another to define a final molding cavity whose volume is less than that of the initial molding cavity. After cooling and disassembling of the two facing mold inserts, the weld line free minus power lens element is recovered. One of the two facing mold inserts comprises a flat surface facing the initial molding cavity, thereby to form a flat surface on one side of the weld line free minus power lens element. The other of the two facing mold inserts comprises a convex surface facing the initial molding cavity, thereby to form a concave surface on an opposite side of the weld line free minus power lens element.