Patent ID: 7211311

Claim:
A sheet material comprising a first fold line and a second fold line, the first and second fold lines being defined by a series of at least partial perforations in the sheet material, wherein there are no at least partial perforations at an intersection of the first fold line and the second fold line, wherein an intersection spacing is defined, and wherein the intersection spacing in a direction along either the first or second fold lines is larger than the spacing between the at least partial perforations of the first or second fold lines, wherein there is a non-perforated section at an intersection of a fold line with an edge of the sheet material, and in which the at least partial perforations stop short of an intersection of a fold line with an edge of the sheet material; and wherein amongst at least one series of the at least partial perforations there is a further non-perforated section located between a first fold line intersection and one of a second fold line intersection and an intersection of a fold line with an edge of the sheet, and wherein in a direction along the at least one fold line the length of the further non-perforated section is greater than the spacing between the at least partial perforations.