Patent DE-102008014902-A1 (DE)
Title: Manufacturing plastic article such as optical lens, comprises connecting mold side parts and a casting ring to form an open casting mold, filling the formed mold with polymerizable monomer resin, and hardening the resin to form the article
Inventor: BECK REINER
IPC: B29D11/00
Filed: 2008-03-19
Abstract: The method comprises connecting first and second mold side parts and a casting ring (2) to form a tray-like open casting mold, arranging a foil (5) with a curvature on the inner side of the first mold side part, filling the formed mold with polymerizable monomer resin, horizontally aligning the formed mold provided with the foil and filled with the monomer resin, so that the second mold side part is arranged on top, and hardening the monomer resin after the foil moves itself in a surface-near area in the direction of the inner side of the second side part to form a plastic article. The method comprises connecting first and second mold side parts and a casting ring (2) to form a tray-like open casting mold, arranging a foil (5) with a curvature on the inner side of the first mold side part, filling the formed mold with polymerizable monomer resin, horizontally aligning the formed mold provided with the foil and filled with the monomer resin, so that the second mold side part is arranged on top, and hardening the monomer resin after the foil moves itself in a surface-near area in the direction of the inner side of the second side part to form a plastic article. The casting ring is connected with a reservoir. During the arrangement step, blisters or air inclusions are not present between the foil and the inner side of the first mold side part. The reservoir includes the polymerizable monomer resin having a higher density compared to the foil, so that the reservoir exercises a hydrostatic pressure on the formed mold after filling with the monomer resin. The curvature of the foil corresponds to the curvature of the inner side of the second mold side part. The first and second mold side parts are opposite to each other, so that the reservoir is arranged above the highest point of the monomer resin in the formed mold. The foil upwardly and vertically moves by the monomer resin due to the density variation between the monomer resin and the foil before or during the hardening process. The plastic article has the foil at the surface-near area related to the inner side of the second mold side part and the foil presents over their entire surface equidistantly to the surface of the plastic article. The inner side of the first mold side part and/or the second mold side part has a flat surface, a convex curvature or concave curvature. The foil has an identical dimension or a smaller dimension compared to the mold side parts. The arrangement step is carried out by introducing drops of the monomer resin and bubble-freely distributing the monomer resin drops between the foil and the inner side of the first mold side part or by air bubble freely placing the foil on the inner side of the first mold side part. The foil is a photochromic foil, a polarizing foil, a foil with electrical conductivity characteristics, a foil with thermal conductivity characteristics, an electrochromic foil, an optical fiber foil, a coloring foil, a breaking strength enhancing foil, foil that alters refractive index, a multiple functional foil and/or a multi-layer foil from the preceding foils. The foil has a thickness of 0.1-2 mm and a density of 0.7-3.0 g/cm 3>at 20[deg] C. The viscosity of the monomer resin is 0.5-3000 mPas at 20[deg] C and the density of the monomer resin is 0.7-3.0 g/cm 3>at 20[deg] C. The density variation between the foil and the monomer resin is 0.01-2.0 g/cm 3>at 20[deg] C. The foil has a distance of 0.1-2 mm from the surface of the formed plastic article and is arranged equidistantly to the surface of the plastic article. An independent claim is included for a plastic article.