Profile: Curtius Trading, Inc. offers used envelope equipment. We also provide silicone release liner, window film, glue and adhesives. Our silicone release liner is a paper film with a silicone coating on one or both sides. It is used for the closing flap on silicone envelopes. We also offer a full range of services, including reconditioning & upgrading of used envelope machinery, on-site equipment installation, new plant start-ups and on-site operator training.