GB1507334A - Container sub-assemblies having a membrane type closure - Google Patents

Abstract

1507334 Containers and closures therefor PROCTER & GAMBLE CO 11 July 1975 [12 July 1974] 29262/75 Headings B8D and B8T [Also in Divisions B4-B5] In a container sub-assembly comprising a closure 42 which is heat sealed to an outwardly rolled rim 48 of a tubular body 41 by induction heating, the closure 42 has a folded-over pull tab 43 and comprises an electrically conductive sheet (75), Fig. 10 (not shown), and an electrically insulating thermoplastic coating (76) Fig. 10 (not shown), and the tubular body 41 comprises a liner 50 including a layer (54), Fig. 4 (not shown), of electrically conductive material and a layer (53), Fig. 4 (not shown), of thermoplastic material which co-operates with said thermoplastic coating (76) to effect the heat sealed connection between the closure and the body. The electrically conductive sheet (75) and layer (54) are of aluminium. The thermoplastic coating (76) is ethylene vinyl acetate and the thermoplastic layer (53) comprises an ionomer resin or polypropylene. The closure 42 also comprises an outer layer of vinyl washcoat. The liner 50 comprises a helically wound and lap sealed web of four layer construction, the innermost, first layer being said thermoplastic layer (53), the second layer being said aluminium layer (54), the third layer (55), Fig. 4 (not shown), being of polyethylene and the fourth, outermost layer (56), Fig. 4 (not shown), being of paper. The tab may be circumferentially spaced from, Fig. 2 (not shown), or superjacent, Fig. 15 (not shown), the location where the top seal of the liner intersects the rolled rim 48, the heat seal below the tab having a greater tensile strength in the first-mentioned arrangement than the heat seal, effected under the same conditions, below the tab in the latter arrangement. One or more apertures (120, 121, 123), Figs. 16 to 19 (not shown), may be provided at the base of the tab. The closure 42 is covered by an overcap 44, the top panel 80 of which has on its underside a plurality of circumferentially spaced, radially extending ribs 85 of thermoplastic material. The overcap 44 is assembled with the closure 42 and the body 41 prior to heat sealing of the latter, and the ribs 85 conform to an upwardly facing annular area of the rim 48 upon the induction heating and pressing of the overcap 44 against the closure 42. The bottom of the container sub-assembly may be hermetically closed by a crimped on bottom closure.