Sleeve-type closures for dispenser nozzles

Reusable sleeve closures comprising a flexible thin sleeve of film grade plastic which seals the nozzle of a partially used sealant, mastic or caulk-dispensing cartridge or squeeze tube to substantially retard the hardening of the remaining tube contents. The plastic film provides a vapor barrier against exit of water or organic solvent from the sealant composition, and/or retards diffusion of oxygen that could cause the composition to set. The film is preferably somewhat stretchable and without creep over time, so that the sleeve provides an extremely tight seal for a substantial distance along the nozzle, e.g. film grade polyolefin or polyvinylidene chloride copolymer plastic film. The sleeve length is preferably long enough to provide a head space for a visual and tactile indicator of content condition. Sleeves may be packaged with the cartridge, or provided after-market. A 4-mil film polyolefin sleeve preserves water-based acrylic caulk over 9 months.