Seam joining together at least two web materials

A seam joining together at least first and second web materials, at least one of which comprising heat fusible material, the first web material having a side edge overlapping with a side edge of the second web material, wherein an overlapped portion is formed where said web materials overlap, said web materials in said overlapped portion being bonded together in a bonding pattern extending over at least a part of the overlapped portion to form said seam, said overlapped portion having a longitudinal and transverse direction and a pair of longitudinal side edges defined by said overlapping side edges of the web materials, wherein said bonding pattern comprises a main bonding pattern extending in the longitudinal direction along at least a part of the overlapped portion, and at least one edge bonding pattern extending in the longitudinal direction along and adjacent at least a part of at least one of said side edges, wherein said main bonding pattern is defined in the longitudinal direction by an outer limiting margin and said edge bonding pattern is defined in the longitudinal direction by an inner limiting margin, wherein the distance between said outer and said inner limiting margin is at least 1.5 mm such that the main bonding pattern is spaced from the edge bonding pattern by at least 1.5 mm, and the bonded area of said edge bonding pattern(s) occupies no more than 30% of the total bonded area of the main bonding pattern plus the bonded area of the edge bonding pattern(s).