Method and apparatus for making improved laminating film

Claim 1

The method of manufacturing a film suitable for use in lamination under heat and pressure which comprises: (1) co-extruding concentric annuli of a polyester as the inner annulus and a polyolefin based resin as the outer annulus while rotating said annuli about their common axis during extrusion, (2) quenching the extrudate to form a multi-layer seamless tube, (3) heating the tube to a temperature suitable for biaxial orientation, (4) providing an air bubble in the heated tube to expand the diameter thereof to a diameter greater than that of the original extrudate to thereby orient the tube biaxially by molecular orientation, (5) cooling the biaxially oriented tube sufficiently to retain its molecular orientation, (6) collapsing the tube, (7) heating the tube to a heat-set temperature in excess of the temperature at which the film is to be laminated while restraining shrinkage thereof to a predetermined dimension, and (8) slitting the edges of the tube to form a pair of flat films which retain some transverse shrinkage properties.

Claim 2

The method of manufacturing a film suitable for use in lamination under heat and pressure which comprises: (1) co-extruding concentric annuli of a polyester as the inner annulus and a polyolefin based resin as the outer annulus while rotating said annuli about their common axis during extrusion, (2) quenching the extrudate to form a multi-layer seamless tube, (3) heating the tube to a temperature suitable for biaxial orientation, (4) providing an air bubble in the heated tube to expand the diameter thereof to a diameter greater than that of the original extrudate to thereby orient the tube biaxially by molecular orientation, (5) cooling the biaxially oriented tube sufficiently to retain its molecular orientation, (6) collapsing the tube, (7) heating the tube to a heat-set temperature in excess of the temperature at which the film is to be laminated while restraining shrinkage thereof to a predetermined dimension, and (8) slitting the edges of the tube to form a pair of flat films which retain some transverse shrinkage properties.

Claim 8

The method of manufacturing a film suitable for use in lamination under heat and pressure which comprises: (1) co-extruding concentric annuli of a polyester resin as the inner annulus, an adhesive, polyolefin based resin as a middle annulus, and a polyolefin based resin having adhesive properties toward the desired substrate as the outer annulus while rotating said annuli about their common axis during extrusion, (2) quenching the extrudate to form a three-layer seamless tube, (3) collapsing the tube, (4) heating the collapsed tube to a temperature suitable for biaxial orientation, (5) providing an air bubble in the heated tube to expand the diameter thereof to a diameter greater than that of the original extrudate to therebv orient the tube biaxially by molecular orientation, (6) cooling the biaxially oriented tube sufficiently to retain its molecular orientation, (7) collapsing the tube, (8) heating the tube to a heat-set temperature in excess of the temperature at which the film is to be laminated while restraining shrinkage thereof to a predetermined dimension, and (9) slitting the edges of the tube to form a pair of flat films which retain some transverse shrinkage properties.

Claim 9

The method of manufacturing a film suitable for use in lamination under heat and pressure which comprises: (1) co-extruding concentric annuli of a polyester resin as the inner annulus, an adhesive, polyolefin based resin as a middle annulus, and a polyolefin based resin having adhesive properties toward the desired substrate as the outer annulus while rotating said annuli about their common axis during extrusion, (2) quenching the extrudate to form a three-layer seamless tube, (3) collapsing the tube, (4) heating the collapsed tube to a temperature suitable for biaxial orientation, (5) providing an air bubble in the heated tube to expand the diameter thereof to a diameter greater than that of the original extrudate to therebv orient the tube biaxially by molecular orientation, (6) cooling the biaxially oriented tube sufficiently to retain its molecular orientation, (7) collapsing the tube, (8) heating the tube to a heat-set temperature in excess of the temperature at which the film is to be laminated while restraining shrinkage thereof to a predetermined dimension, and (9) slitting the edges of the tube to form a pair of flat films which retain some transverse shrinkage properties.

Claim 14

An apparatus for manufacturing a laminating film which comprises: a co-extrusion head arranged to extrude a plurality of coaxial abutting annuli of differing compositions, means for rotating said co-extrusion head during such extrusion, quenching means disposed beyond said co-extrusion head and arranged to quench the extrudate leaving said coextrusion head, first pressure rollers located beyond said quenching means and arranged to flatten the extruded and quenched annuli into a multi-layer seamless tube, first heater means receiving the flattened tube and arranged to heat said tube to a biaxial orientation temperature, means for expanding the heated flattened tube to a diameter greater than that of said annuli while simultaneously biaxially orienting the same, cooling means positioned to cool the biaxially oriented tube sufficiently to control the orientation layer, second pressure rollers located beyond said cooling means and arranged to flatten the biaxially oriented tube, second heater means located beyond said second pressure rollers and arranged to heat the flattened tube to a heat-set temperature, a spreader positionable inside said flattened tube and arranged to support the tube and limit the amount of film shrinkage induced by said second heater means, and slitter means following said spreader arranged to slit said tube along its edges into a pair of flat films.

Claim 15

An apparatus for manufacturing a laminating film which comprises: a co-extrusion head arranged to extrude a plurality of coaxial abutting annuli of differing compositions, means for rotating said co-extrusion head during such extrusion, quenching means disposed beyond said co-extrusion head and arranged to quench the extrudate leaving said coextrusion head, first pressure rollers located beyond said quenching means and arranged to flatten the extruded and quenched annuli into a multi-layer seamless tube, first heater means receiving the flattened tube and arranged to heat said tube to a biaxial orientation temperature, means for expanding the heated flattened tube to a diameter greater than that of said annuli while simultaneously biaxially orienting the same, cooling means positioned to cool the biaxially oriented tube sufficiently to control the orientation layer, second pressure rollers located beyond said cooling means and arranged to flatten the biaxially oriented tube, second heater means located beyond said second pressure rollers and arranged to heat the flattened tube to a heat-set temperature, a spreader positionable inside said flattened tube and arranged to support the tube and limit the amount of film shrinkage induced by said second heater means, and slitter means following said spreader arranged to slit said tube along its edges into a pair of flat films.