US 6,547,912 B2 · Extrusion coating process for making high transparency protective and decorative films

Abstract

A process for making a protective and decorative surfacing film comprises extrusion coating a solventless polymeric material from an extruder die to form an optically clear first layer on a polyester carrier sheet traveling past the extruder die opening. The extrusion coated first layer is immediately cooled on the carrier sheet to harden it, followed by applying a pigmented second layer to the first layer. The composite paint coat is transferred to a reinforcing backing sheet, after which the carrier sheet is separated from the paint coat to expose the outer surface of the first layer as a high gloss surface with a high distinctness-of-image, providing a transparent protective outer coat for the pigmented second layer. The pigmented second layer can be solvent cast and dried or extruded and hardened as a separate coating on the first layer. The composite paint coat can be bonded to a coextruded size coat and semi-rigid plastic substrate panel to form a thermoformable laminate. Techniques are disclosed for producing extruded clear films of exceedingly high optical clarity using a closed air flow transport and HEPA filtration system that removes airborne particles from the resin handling and extrusion process, thereby preventing micron-sized contaminants naturally present from many sources from entering the process and degrading ultimate film quality.

Claims40

Dependent claims

A process for extruding a high transparency clear film from a particulate resinous starting material, comprising the steps of:

providing a solventless resinous starting material in particulate form essentially free of particulate contaminants above about 10 microns in size, the resinous material contained in a sealed container to prevent introduction of airborne contaminants from the ambient environment;
conveying said resinous material from the sealed container to an extrusion apparatus in a closed airflow transport system in which transport air for conveying said resinous material is subjected to high efficiency particulate air (HEPA) filtration that produces HEPA filtered transport air to prevent introduction of airborne contaminants, having a particle size as low as 10 microns, from the ambient environment into the airflow that transports the resinous material to the extrusion apparatus;
in which the resinous starting material is conveyed from the sealed container to a dryer for drying at least a portion of the resinous starting material prior to transporting the dried resinous material to the extrusion apparatus;
in which the resinous material is conveyed from the sealed container to the dryer via said HEPA filtered transport air and in which the resinous material conveyed from the dryer to the extrusion apparatus is transported by said HEPA filtered transport air;
and
extruding the resinous material via the extrusion apparatus to form a transparent extruded clear coat film essentially free of such filtered contaminants.

3 more elements

A process for extruding a resinous material by solventless extrusion to form a high gloss high transparency clear film essentially free of optical defects, comprising the steps of:

providing a solventless resinous starting material in particulate form essentially free of particulate contaminants above about 10 microns in size, the resinous material contained in a sealed container to prevent introduction of airborne contaminants from the ambient environment;
conveying said resinous material from the sealed container to an extrusion apparatus in a closed airflow transport system in which transport air for conveying said resinous material is subjected to high efficiency particulate air (HEPA) filtration that produces HEPA filtered transport air to prevent introduction of airborne contaminants, having a particle size as low as 10 microns, from the ambient environment into the airflow that transports the resinous material to the extrusion apparatus;
in which the resinous starting material is conveyed from the sealed container to a dryer for drying at least a portion of the resinous starting material prior to transporting the dried resinous material to the extrusion apparatus;
in which the resinous material is conveyed from the sealed container to the dryer via said HEPA filtered transport air and in which the resinous material conveyed from the dryer to the extrusion apparatus is transported by said HEPA filtered transport air;
extrusion coating said resinous material through an extrusion die, contained in said extrusion apparatus, onto a carrier sheet traveling past an extrusion die opening of the extrusion die to form said extruded clear film on the carrier sheet in which the extruded clear film is essentially free of such filtered contaminants;
and
immediately hardening the clear film on the traveling carrier sheet.

4 more elements

A process for making a high transparency extruded polymeric film, comprising:

providing a solventless resinous starting material in particulate form essentially free of particulate contaminants above about 10 microns in size, the resinous material contained in a sealed container to prevent introduction of airborne contaminants from the ambient environment;
conveying said resinous material from the sealed container to an extrusion apparatus in a closed airflow transport system in which transport air for conveying said resinous material is subjected to high efficiency particulate air (HEPA) filtration that produces HEPA filtered transport air to prevent introduction of airborne contaminants, having a particle size as low as 10 microns, from the ambient environment into the airflow that transports the resinous material to the extrusion apparatus;
in which the resinous starting material is conveyed from the sealed container to a resin dryer for drying at least a portion of the resinous starting material prior to transporting the dried resinous material to the extrusion apparatus;
in which the resinous material is conveyed from the sealed container to the resin dryer via said HEPA filtered transport air in a closed airflow transport line and in which the resinous material conveyed from the dryer to the extrusion apparatus is transported by said HEPA filtered transport air;
in which drying air forced through the dryer for drying said starting material is treated in a separate air dryer for removing moisture from the drying air, and in which the drying air is subjected to HEPA filtration for removing airborne contaminants greater than about 10 microns in size from the drying air;
in which the dried extrudable polymeric starting material is conveyed in a HEPA filtered closed air flow transport line from the resin dryer to the extrusion apparatus;
and
extruding the dried starting material via the extrusion apparatus to form a highly transparent polymeric film essentially free of defects caused by said filtered airborne contaminants.

5 more elements

A process for making a high transparency polymeric film comprising:

providing a solventless resinous starting material in particulate form essentially free of particulate contaminants above about 10 microns in size, the resinous material contained in a sealed container to prevent introduction of airborne contaminants from the ambient environment;
conveying said resinous material from the sealed container to an extrusion apparatus in a closed airflow transport system in which transport air for conveying said resinous material is subjected to high efficiency particulate air (HEPA) filtration that produces HEPA filtered transport air to prevent introduction of airborne contaminants, having a particle size as low as 10 microns, from the ambient environment into the airflow that transports the resinous material to the extrusion apparatus;
in which the resinous starting material is conveyed from the sealed container to a dryer for drying at least a portion of the resinous starting material prior to transporting the dried resinous material to the extrusion apparatus;
in which the resinous material is conveyed from the sealed container to the dryer via said HEPA filtered transport air and in which the resinous material conveyed from the dryer to the extrusion apparatus is transported by said HEPA filtered transport air;
subjecting at least a portion of the starting material to HEPA filtered drying air in a dryer;
extruding the dried starting material through an extruder die contained in the extrusion apparatus to form a melt cast film coated on a traveling casting sheet;
removing airborne contaminants greater than about 10 microns in size from the casting sheet at least before the coating is extruded onto the casting sheet;
and
hardening the coated film on the casting sheet by a temperature reduction to form a finished polymeric film on the casting sheet and thereafter removing the casting sheet from the finished film to provide a high transparency polymeric film essentially free of defects caused by said filtered airborne contaminants.

6 more elements

Dependencies are inferred from the claim text.

Extrusion coating process for making high transparency protective and decorative films

Life of this patent

Extrusion coating process for making high transparency protective and decorative films

Life of this patent

Abstract

Claims40