process for covering glass in particular glass containers such as jars, jars and boxes with plastic products

摘要

1515541 Coating glass receptacles with thermosetting resin RESICOAT GmbH BESCHICHTUNGSPULVER 23 May 1975 [3 July 1974] 22998/75 Heading B2E Glass receptacles are coated with a thermosetting resin which has been softened prior to application either by addition of a softening agent or by internal softening, in order to provide a scratch-resistant, shatter-proof, alkali-stable article of low frictional resistance. The resin may be applied as granules of size less than 125Ám by electrostatic spraying or by immersion in a vortex bed or an electrostatic vortex bed. The receptacle may be pretreated with an adhesion promoter and may be preheated to at least 50‹C. The coating may be hardened in a convection or infrared oven at 150-250‹C, unless the preheating renders this unneccessary and may be at least 50Ám thick. Specified resins: epoxy, acrylate, polyester and polyurethane. Softening agents for addition to resins include epoxide esters, epoxidised oils, thermoplastic polyesters and polyvinyl butyrals. Internal softening may be achieved by including a softening substance which reacts to form part of the resin, e.g. as follows. Epoxy resins: by condensing bisphenol A and epichlorohydrin in a molar ratio of 0.80-0.95, or by partial esterification. Polyesters: by including at least 10 wt.% of certain glycols and aliphatic acids. Acrylates: by including at least 10 wt.% of certain acrylic acid esters. Polyurethanes: by rising blocked isocyanates as a cross-linking agent.