Ppg Industries, Inc.

David A Allerton

Dennis S Postupack

Richard L Emmert

This invention relates to a method of and apparatus for forming a colored shade band on an elongated area of a flexible sheet of interlayer material comprising applying a dye composition by electrostatic spraying against an elongated area of a surface of a flexible sheet of non-conductive interlayer material such as polyurethane or plasticized polyvinyl butyral. A flexible sheet to be coated is mounted on a support carriage at a loading and unloading chamber in a substantially horizontal support plane, is transferred to a coating chamber, is tilted into an oblique plane at said coating chamber where it is aligned with a platen mask, electrostatic spray means disposed to one side of said platen mask supplies an electrostatic spray of a dye composition through said platen mask to the elongated area of said flexible sheet. The coated sheet pivots back to a substantially horizontal support plane and is returned to the loading and unloading station, where the coated flexible sheet is removed and another sheet mounted for treatment. The flexible sheet so coated is useful as an interlayer in shaded, bent laminated safety glass windshields.

Method for supporting flexible sheet while applying graded shade band

Forming a colored shade band on an elongated area of a flexible sheet of interlayer material comprising applying a dye composition by electrostatic spraying against a portion of a surface of a flexible sheet of non-conductive interlayer material such as polyurethane or plasticized polyvinyl butyral. A novel grounded shielding structure of electroconductive material comprises a primary shield located in close proximity to the upper surface of a workpiece to be partially coated. A preferred embodiment comprises primary and secondary shields with an optional manifold between the shields to ensure superior control of a pattern of graded intensity along the transverse dimension of an elongated area to be coated. One or both shields may be heated to avoid the deposit of spray particles that cause optical defects. The workpiece so coated is useful as an interlayer in shaded, bent laminated safety glass windshields.

Apparatus for forming graded shade band on substrate

Apparatus for supporting flexible sheet while applying graded shade band

Method for forming graded shade band on substrate

An electrostatic spray process for the formation of a shade band on a polymeric innerlayer for laminated safety glass is disclosed. The improvement comprises using a solvent system of N-lower alkyl-pyrrolidone and tetrahydrofuran. This solvent system combines high dye solubility for process efficiency with proper volatility for optimum aesthetic quality in the finished product.

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Glenshaw, PA, United States of America

David A Allerton