Method for removal of curling of circuit printable flexible substrate

Claim 1

A method for continuously removing curl from a circuit printable continuous flexible elongated substrate, the substrate having longitudinal and width directions and comprising a copper foil and a film layer of an aromatic polyamideimide or an aromatic polyimide which was formed by coating a layer of a solution of (i) an aromatic polyamideimide, (ii) an aromatic polyimide precursor or (iii) an aromatic polyimide on said copper foil, and drying the coated solution layer to cause it to set whereby the copper foil surface curls outwardly in the direction of the coated surface thereof, the method comprising: moving under tension the curled coated continuous flexible substrate in the longitudinal direction thereof; passing and sliding said moving coated curled substrate, under a tension force of 15 to 200 grams per 1 cm of width of the substrate, over a curved surface with said metal foil layer being in contact with said curved surface, said curved surface having a radius of curvature of 1 to 10 mm, said substrate sliding over and relative to said curved surface while passing thereover, the relative sliding speed being within the range of 3-300 cm/min.; turning said substrate around said curved surface at a turning angle of not less than 90°; and maintaining the temperature during said passing and sliding step to be no higher than 80° C.

Claim 2

A method for continuously removing curl from a circuit printable continuous flexible elongated substrate, the substrate having longitudinal and width directions and comprising a copper foil and a film layer of an aromatic polyamideimide or an aromatic polyimide which was formed by coating a layer of a solution of (i) an aromatic polyamideimide, (ii) an aromatic polyimide precursor or (iii) an aromatic polyimide on said copper foil, and drying the coated solution layer to cause it to set whereby the copper foil surface curls outwardly in the direction of the coated surface thereof, the method comprising: moving under tension the curled coated continuous flexible substrate in the longitudinal direction thereof; passing and sliding said moving coated curled substrate, under a tension force of 15 to 200 grams per 1 cm of width of the substrate, over a curved surface with said metal foil layer being in contact with said curved surface, said curved surface having a radius of curvature of 1 to 10 mm, said substrate sliding over and relative to said curved surface while passing thereover, the relative sliding speed being within the range of 3-300 cm/min.; turning said substrate around said curved surface at a turning angle of not less than 90°; and maintaining the temperature during said passing and sliding step to be no higher than 80° C.

Claim 13

A method for continuously removing curl from a circuit printable continuous flexible elongated substrate, the substrate having longitudinal and width directions and comprising a metal foil and a film layer of an aromatic polyamideimide or an aromatic polyimide which was formed by coating a layer of a solution of (i) an aromatic polyamideimide, (ii) an aromatic polyimide precursor or (iii) an aromatic polyimide on said metal foil, and drying the coated solution layer to cause it to set whereby the metal foil surface curls outwardly in the direction of the coated surface thereof, the method comprising: moving under tension the curled coated continuous flexible substrate in the longitudinal direction thereof; passing and sliding said moving coated substrate under tension over a first curved surface with said metal foil layer being in contact with said first curved surface, said first curved surface having a radius of curvature of 0.5-25 mm and said first curved surface extending in a given direction at an angle of 20°-70° relative to the width direction of said substrate, said substrate sliding over and relative to said first curved surface while passing thereover, and turning said substrate around said first curved surface at a turning angle of not less than 90°, and the temperature during said passing step being no higher than 80° C.; and passing and sliding said moving coated substrate under tension over a second curved surface after leaving said first curved surface, and with said metal foil layer being in contact with said second curved surface, said second curved surface having a radius of curvature of 0.5-25 mm and said second curved surface extending in a given direction at an angle of 70°-110° relative to the width direction of said substrate, said substrate sliding over and relative to said second curved surface while passing thereover, and turning said substrate around said second curved surface at a turning angle of not less than 90°, and the temperature during said passing of said substrate over said second curved surface being no higher than 80° C.

Claim 14

A method for continuously removing curl from a circuit printable continuous flexible elongated substrate, the substrate having longitudinal and width directions and comprising a metal foil and a film layer of an aromatic polyamideimide or an aromatic polyimide which was formed by coating a layer of a solution of (i) an aromatic polyamideimide, (ii) an aromatic polyimide precursor or (iii) an aromatic polyimide on said metal foil, and drying the coated solution layer to cause it to set whereby the metal foil surface curls outwardly in the direction of the coated surface thereof, the method comprising: moving under tension the curled coated continuous flexible substrate in the longitudinal direction thereof; passing and sliding said moving coated substrate under tension over a first curved surface with said metal foil layer being in contact with said first curved surface, said first curved surface having a radius of curvature of 0.5-25 mm and said first curved surface extending in a given direction at an angle of 20°-70° relative to the width direction of said substrate, said substrate sliding over and relative to said first curved surface while passing thereover, and turning said substrate around said first curved surface at a turning angle of not less than 90°, and the temperature during said passing step being no higher than 80° C.; and passing and sliding said moving coated substrate under tension over a second curved surface after leaving said first curved surface, and with said metal foil layer being in contact with said second curved surface, said second curved surface having a radius of curvature of 0.5-25 mm and said second curved surface extending in a given direction at an angle of 70°-110° relative to the width direction of said substrate, said substrate sliding over and relative to said second curved surface while passing thereover, and turning said substrate around said second curved surface at a turning angle of not less than 90°, and the temperature during said passing of said substrate over said second curved surface being no higher than 80° C.