Sleeve-type closures for dispenser nozzles

Abstract

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.

Description

[0001] The benefit is claimed under 35 USC .sctn. 119 (e) of the filing date of Provisional Application Ser. No. 60 / 179,585 filed Feb. 1, 2000 under the same title by the same inventor.FIELD[0002] The invention relates to closures for nozzles of dispensing cartridges and squeeze tubes, more particularly to a flexible sleeve of plastic film that hermetically seals the nozzle of a fresh or partially-used sealant, mastic, adhesive, glazing or caulk-dispensing cartridge or squeeze tube so that the remaining unused contents do not set. The sleeve(s) may be packaged with the cartridge, or may be provided as an after-market replacement used alone or in combination with ordinary nozzle caps.[0003] It is common practice to package sealant, mastic, adhesive, glazing, caulk and glue compositions in plastic or metal squeeze tubes, or plastic or plastic coated or impregnated paper cartridges which are adapted to be loaded into extrusion devices, ordinarily called caulking guns, in order to dispe...

AI Technical Summary

Benefits of technology

[0013] The invention comprises a flexible sleeve of plastic film which tightly fits over the open nozzle of sealant dispenser cartridges and squeeze tubes to provide a hermetic seal to prevent or substantially retard, on a long term basis, the hardening of the remaining contents of the cartridge or tube after its initial use. The plastic film may range widely in composition and thickness including multi-layer and copolymer film, so long as it has the functionality of providing a vapor barrier against exit of water or organic solvent from the sealant composition, and prevent or retard diffusion thereinto of such quantities of oxygen as would cause the composition to set in the case of air-settable compositions. The plastic film is preferably heat sealable, somewhat stretchable and not subject to substantial relaxation or creep over time, so that when the sleeve is inserted over the open nozzle and pulled or pushed downwardly thereon, it provides an extremely tight seal for a substantial distance along its length.

[0019] By virtue of the fact that the selected plastic of the sleeve is somewhat stretchable, the side seams need not be tapered, but may be parallel, since as the sleeve is pulled down over the nozzle, it configures tightly and completely around the nozzle from just below the tapered tip to the base of the shank adjoining the cartridge or squeeze tube top thus providing an excellent hermetic seal. Thus, the preferred minimum stretchability of the film is the ratio of the nozzle base width to the width of the nozzle at the top of the seal area, typically at the tip taper; for a consumer caulk cartridge this is about 1.25 to about 1.5, and can range up to about 3.5 to about 5 for commercial cartridges. The greater the area of contact, the better the seal. The pocket length is preferably longer than the cut nozzle to provide a small head space at the top of the pocket for any excess sealant or mastic, which may be extruded from the open tube end. This also provides a visual indicator of the condition of the tube contents. As long as the composition within that head space remains soft and pliable, it indicates that the contents of the tube have not dried out or set from the nozzle end. It should be understood that the tube could dry out from the plunger end in the event of a defective piston seal.

[0020] The side seams should be of sufficient strength and / or width, and the film of sufficient thickness, strength and stretchability to ensure that the sleeve does not split open when it is pulled down over the nozzle of the dispenser cartridge and retain its integrity over the life of the sealing sleeve, up to a year or more. Typically, a seam width on the order of {fraction (1 / 16)}"-{fraction (3 / 16)}" (2-6 mm) is adequate, but it may be any suitable width depending on its integrity and strength. Additional plastic material may be provided outwardly of one or more of the seams, preferably both sides, to permit ease of handling, and may be configured to provide graspable wings or flanges for mounting and removing the sleeve. Further, a V-shaped or semi-circular shaped notch (presently preferred) or depending flap may be provided at the opening end of the sleeve in one or both sheets of plastic to permit ease of opening the sleeve pouch to permit insertion of the nozzle. A plurality of sleeves may be provided in a strip, preferably with each separable from the other by a line of perforations so that each sleeve can be torn from the strip as needed.

[0022] In actual testing, a polyolefin plastic sleeve having a thickness on the order of 4 mils maintains the freshness and prevents drying out of water-based acrylic caulk in excess of nine months. The sleeve is easily removed by hand by simply slipping it off the nozzle. The sleeve may be reused, and due to its conformable nature, on reuse, provides an excellent seal along its length. Any sealant or mastic in the headspace of a removed sleeve can be prevented from drying out by partly flattening the sleeve, beginning at the open end. That is not possible with a rigid cap, and thus the inventive seal provides still another significant and unexpected advantage over conventional cap-type closures.

[0024] The invention thus solves the long felt need of substantially retarding or preventing hardening of residual sealant and mastic composition in dispenser cartridges and tubes, while conserving materials and being environmentally friendly. It also results in economies for the users, and adds both real and perceived value for the consumer to those caulk, sealant and mastic cartridge and squeeze tube products which offer the inventive sleeves as a solution to the well-known wastage as occurs by use of conventional caps.

Problems solved by technology

In addition to being uneconomic, disposal of excess composition represents a considerable waste of resources and is highly undesirable for environmental reasons.

At present, there is no known recycling available for the wide variety of sealant and mastic compositions being distributed today.

However, since the plastic of which the caps and nozzles are made has very low tensile strength, it is easy to over-tighten the screw caps, causing them to split.

Likewise, a bead and groove does not provide a hermetic seal for any substantial length of time.

These solutions are temporary at best and typically do not prevent drying out of the contents for more than a few weeks, especially when there is residual pressure on the contents, which results in pushing off the cap.

However, most tubes do not fit in Ziploc.RTM. bags, the plastic is thin (on the order of 1 mil or less), and the bags with the cartridge in them contain so much air as to defeat the purpose.

The wrapping approach simply does not provide an adequate seal.

However, they also suffer from the problem of the caps splitting when they are screwed down too tightly, or not providing a good hermetic seal when the threads, beads or grooves become clogged with partially set or dried sealant material.

Finally, this class of packaging also suffers from the same types of poor cap fit problems as the more common caulk tube type dispensing cartridges.

Thus, in both classes of sealant and mastic packaging (cartridges and squeeze tubes), where the contents of the cartridge or tube are not entirely dispensed during a particular caulking or gluing operation, if precautions are not taken to carefully and redundantly reseal the nozzle, the remaining caulking compound will harden, due to exposure to the atmosphere.

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