Laminates of films and methods and apparatus for the manufacture

Laminate according to any preceding claims characterised in that the width of each bonding zone is no less than 15% preferably no less than 20% and still more preferably no less than 30% of the wavelength.

Laminate according to any of the preceding claims characterised in that the width of the non-bonded zone of A as measured between the two adjacent bonding zones and measured along its curved surfaces is no less than 10% and preferably no less than 20% longer than the corresponding linear distance.

Laminate according to any of the preceding claims characterised in that A, within each non-bonded zone and outside the first attenuated zone if such zone is present, is molecularly oriented mainly in a direction parallel to the direction of the flutes or in a direction close to the latter as determined by shrinkage tests.

Laminate according to any of the preceding claims, characterised in that B has a lower coefficient of elasticity than A, both as measured in the direction perpendicular to the flute direction.

Laminate according to any of the preceding claims, characterised in that it comprises at least two films which each has a main direction of orientation and which are laminated so that the said two directions cross each other.

Laminate according to any of the preceding claims, in which said first attenuated zones are present in A characterised in that each such zone of attenuated A, if it extends beyond the corresponding zone of bonding into a non-bonded zone of A, is limited to a width which leaves more than half of and preferably no less than 70% of the width of the non-bonded zone, as not belonging to any first attenuated zone, this width being measured along the curved surfaces.

Laminate according to any of the preceding claims, characterised in that the wavelength of A is no more than 2.5 mm, preferably no more than 2 mm and more preferably no more than 1.5 mm.

Laminate according to any of the preceding claims, characterised in that it comprises a further non-waved monofilm formed or multifilm formed ply (C) of thermoplastic polymer material, C being bonded to the crests of A on the second side of the latter through a lamination layer.

Laminate according to any of the preceding claims characterised in that it comprises a further monofilm formed or multifilm formed ply (D) consisting of thermoplastic, cold-orientable polymer material, said ply having waved flute configuration, the crests on one side of D being bonded to the second side of B through a lamination layer, and the wavelength of D's flute configuration preferably being no more than 3 mm.

Laminated according to any of the preceding claims, characterised in that at least some of the flutes are flattened at intervals and preferably bonded across each ones entire width at the flattened locations to make the flute form a row of narrow closed elongated pockets.

Laminate according to any of the preceding claims, characterised in that the bonding of the crests on A, is effected through selected surface layers formed in a co-extrusion process.

Laminate according to any of the preceding claims, characterised in that the mono- or multifilm formed plies mainly consist of polyolefin.

Laminate according to any of the preceding claims, characterised in that A and B each has a main direction of orientation, either by being uniaxially oriented or unbalanced biaxially oriented, or by in itself being a cross.-laminate of uniaxially oriented or unbalanced biaxially oriented films, such cross-laminate exhibiting a resultant main direction of orientation, whereby the resultant main direction of orientation in A is generally parallel with the longitudinal direction of the flutes, while the resultant main direction of orientation in B forms an angle to the said direction in A.

Laminate according to any of the preceding claims, characterised in that at least some of the channels formed by the flutes and the matching non-waved film material, which channels may be closed to pockets, contain a filling material in particulate, fibrous, filament or liquid form.

Method of manufacturing a laminate or monofilm formed or multifilm formed ply (A) with another monofilim formed or multifilm formed ply (B) both consisting of thermoplastic polymer material in which A has a waved flute configuration while B is not waved, and B on a first side is adhesively bonded in zones to the crests on a first side of A, in which further the waved flute structure is formed by the use of a grooved roller, and the said bonding with B is carried out under heat and pressure and also under use of a grooved roller, and at least A is selected as mainly consisting of solid-state orientable material, characterised in that the division on the grooved roller which produces the lamination on the said crests is at the highest 3 mm.

Laminate according to any of the preceding product claims, characterised in that there is print on A and/or B in the non-bonded zones, the bonded zones being generally devoid of such print.

Method according to any of the preceding method claims, characterised in that A and/or B is printed on the surface to become the inside of the laminate, the printing process being in register with the flute-forming and lamination processes so as to limit the print generally to the non-bonded zones.

Apparatus according to 85 in which the bag forming station forms gusseted bags with gusseted bottoms and heat-sealed sides, and in which the bottoms are parallel with the flutes.