Composite films with an obscuration area

1 . A composite film comprising:

a film A containing a polyvinyl acetal and optionally a plasticiser; and

a carrier film,

wherein film A is provided with an obscuration area,

wherein the obscuration area is provided by a printed or coated ink layer on the surface of film A not facing the carrier film,

wherein a surface roughness Rz of the surface of film A to be coated or printed is from 0.1 to 3.0 μm, measured before said surface is coated or printed on, and

wherein a surface roughness Rz of the carrier film on the surface in contact with film A is from 2.0 to 6.0 μm, measured before the carrier film and the film A come into contact.

2 . The composite film according to claim 1 wherein the carrier film contains a polymer selected from the group consisting of polylactic acid, acrylonitrile-butadiene-styrene copolymer, polyamides, polycarbonates, polyethylene terephthalate, polyethylene terephthalate copolymers, polyhydroxyalkanoates, polyurethanes, polyolefins, acrylonitrile styrene acrylate, polyacrylates and polymethacrylates, polyvinyl alcohol, and TAC (cellulose tri acetate).

3 . The composite film according to claim 1 wherein a thickness of the film A is from 15 to 40 μm.

4 . The composite film according to claim 1 wherein a thickness of the carrier film is from 25 to 250 μm.

5 . The composite film according to claim 1 wherein film A is adhered to the carrier film with an adhesive strength from 0.05 to 10 N/3 cm.

6 . The composite film according to claim 1 wherein the ink comprises a binder selected from the group consisting of vinyl pyrrolidone, a water-soluble acrylic resin, an alcohol-soluble resin, an acrylic resin, a styrene-maleic resin, styrene-acrylate resin, a polyurethane resin, a polyvinyl acetal resin, a polyvinyl alcohol resin and a ketone resin.

7 . A process for the production of the composite film according to claim 1 comprising the following steps, in that order:

a) providing a carrier film;

b) coating one surface of the carrier film with a solution comprising a solvent, the polyvinyl acetal or polyvinyl ethylene acetal, and the optional plasticiser;

c) evaporating the solvent to obtain the film A on the one surface of the carrier film; and

d) providing an obscuration area by printing or coating the surface of the film A not in contact with the carrier film with an ink layer.

8 . A process for the production of a windshield comprising two sheets of glass, combined by an interlayer film comprising a film A containing a polyvinyl acetal and optionally, a plasticiser; and a film B containing a polyvinyl acetal and a plasticiser in an amount of at least 22% by weight; comprising the following steps, in that order:

a) positioning the composite film according to claim 1 to the first glass sheet with the film A facing the first glass sheet;

b) peeling off the carrier film from the film A; and

c) positioning the film B on the film A or on the second glass sheet; and

d) providing a stack of the layers comprising first glass sheet-film A-film B-second glass in that order; and

e) laminating the stack obtained in step d) to produce the windshield.

9 . A process for the production of a windshield comprising two sheets of glass, combined by an interlayer film comprising a film A containing a polyvinyl acetal and optionally, a plasticiser; and a film B containing a polyvinyl acetal and a plasticizer in an amount of at least 22% by weight; comprising the following steps, in that order:

a) positioning the composite film according to claim 1 to the film B with the film A facing the film B;

b) peeling off the carrier film from the film A;

c) providing a stack of the layers comprising first glass sheet-film A-film B-second glass in that order; and

d) laminating the stack obtained in step c) to produce the windshield.

10 . A process for the production of a windshield comprising two sheets of glass, combined by an interlayer film comprising a film A containing a polyvinyl acetal and optionally, a plasticiser; and a film B containing a polyvinyl acetal and a plasticizer in an amount of at least 22% by weight; comprising the following steps, in that order:

a) providing the composite film according to claim 1 and peeling off the carrier film from the film A;

b) positioning the film A on the first glass sheet with the surface of film A provided with a printed or coated ink layer away from the first glass sheet;

c) positioning the film B on film A or on the second glass sheet;

d) providing a stack of the layers comprising first glass sheet-film A-film B-second glass in that order; and

e) laminating the stack obtained in step d) to produce the windshield.

11 . A windshield obtained according to the process of claim 8 .