Containers and method of manufacture thereof

Claim 3

A process in accordance with claim 1 wherein said step of forming a preform comprises forming a generally rectangular blank having an upper edge and a lower edge and two side edges and having a plurality of score lines located in a lower marginal area adjacent said lower edge and extending generally perpendicularly toward said lower edge, said score lines being at least approximately uniformly spaced along the extent of said lower edge, convoluting said blank to overlap the side margins adjacent said side edges, and bonding the thus overlapped side margins to form a preform.

Claim 4

A method in accordance with claim 2 wherein said blank and said bottom disc are formed of paperboard having a coating on each side thereof of a synthetic thermoplastic polymeric material, the bonding of said overlapped side margins to each other and the bonding of said bottom disc to said flange being effected by thermal bonding of the contacting thermoplastic coatings.

Claim 5

A process in accordance with claim 3 further comprising crushing a continuous annular area of said flange to collapse said folds to form a liquid-tight seal between said flange and said bottom disc by means of said contacting thermoplastic coatings.

Claim 6

A process in accordance with claim 4 wherein the number of said score lines is sufficiently large so that the thickness at said continuous annular area of each said fold is less than twice the thickness of the wall of said preform, said overlapped side margins being free oF said score lines.

Claim 7

A process in accordance with claim 5 further comprising forming an upwardly opening continuous annular gutter in the peripheral portion of said bottom disc and in the adjacent portion of said flange, the radial dimension with respect to the axis of said preform of said gutter being less than the radial dimension of said flange, the number of said score lines being sufficiently great so that the bottom of said folds at said lower edge do not extend downwardly below the plane of the bottom of said gutter.

Claim 8

A process in accordance with claim 1 wherein said score lines are located completely within the portion of said preform which forms said flange, and wherein said score lines terminate short of said lower edge.

Claim 9

A process in accordance with claim 1 wherein the step of bending said lower marginal area inwardly comprises contacting said lower marginal area with an inwardly curved annular surface which is substantially coaxial with said preform with the apparent apex of said annular surface being remote from said preform to cause a simultaneous inwardly bending of said lower marginal area throughout the extent of said lower edge.

Claim 10

In a container comprising a wall member of substantially circular cross section having a lower portion thereof bent inwardly to form an inwardly directed radial flange, a bottom disc positioned within the hollow of said wall member and in contact with the upper surface of said flange, said disc being structurally bonded to said flange throughout at least a portion of the area of contact therebetween, the improvement comprising said lower portion of said wall member having a plurality of score lines preformed therein prior to the bending of said lower portion of said wall member to form said flange, said preformed score lines being substantially parallel to the axis of the substantially circular cross section of said wall member in the lower portion of said wall member prior to the bending of said lower portion of said wall member to form said flange and substantially radial to said axis in said flange, a fold being formed along each of said score lines in said flange to accommodate the excessive material in said lower portion due to the reduction in diameter thereof in the formation of said flange.

Claim 11

In a container comprising a wall member of substantially circular cross section having a lower portion thereof bent inwardly to form an inwardly directed radial flange, a bottom disc positioned within the hollow of said wall member and in contact with the upper surface of said flange, said disc being structurally bonded to said flange throughout at least a portion of the area of contact therebetween, the improvement comprising said lower portion of said wall member having a plurality of score lines preformed therein prior to the bending of said lower portion of said wall member to form said flange, said preformed score lines being substantially parallel to the axis of the substantially circular cross section of said wall member in the lower portion of said wall member prior to the bending of said lower portion of said wall member to form said flange and substantially radial to said axis in said flange, a fold being formed along each of said score lines in said flange to accommodate the excessive material in said lower portion due to the reduction in diameter thereof in the formation of said flange.

Claim 12

A container in accordance with claim 9 further comprising a continuous annular area of said flange being crushed to collapse said folds in said area to form a liquid-tight seal between said flange and said bottom disc, the number of said score lines being sufficiently great so that the thickness at said continuous annular area of each said fold is less than twice the thickness of said wall member.