Monsanto Company

Robert A Esposito

David Paul Bourcier

John C Hoagland

Van Pelt Brower

Thomas E Soar

Frederick F Valego, Jr

Plasticized polyvinyl butyral sheet optionally containing a gradient color band is formed by continuously extruding a sheet having a predetermined region across its width formed from melt issuing from a die at an increased mass flow rate in comparison with other portions of the melt forming the rest of the sheet and then forwardly distorting such sheet immediately after forming by preferentially stretching the side containing the predetermined region to form an arcuate shape of substantially uniform thickness. Arcuately shaped sections are then cut from the sheet to form discrete, shaped interlayer blanks having improved thickness uniformity and dimensional stability providing improved performance when used in laminated safety glass.

Process for forming plasticized polyvinyl butyral sheet

A shaped interlayer blank adapted for use with glass in a vehicle windshield, such blank formed of plasticized polyvinyl butyral and having a quadrilateral peripheral contour with two sides of arcuate shape and a wedge-shaped thickness profile. The blank preferably has an arcuate gradient color band substantially parallel to an arcuate edge of the blank in the greater thickness region of the blank. The wedge-shaped thickness gradually increases from about 30 mils to about 35 to 40 mils across the width of the blank. The blank is tailored for safety windshields featureing head-up displays where to function effectively the glass layes must be nonparallel and canted with respect to each other.

Shaped interlayer blank

A process for forming intermediate sheeting for forming shaped interlayer blanks comprising extruding plasticized polyvinyl butyral melt into an endless straight-sided sheet having a gradient color band extending along one side, the melt forming the region of the sheet laterally of the color band extruding at a greater thickness than that forming the portion containing the color band, thereby providing a wedge-shaped thickness profile in the sheet, quenching the extruded sheet to set the polymer and winding the sheet in roll form. The intermediate sheet is at least about twenty inches wide and the wedge-shaped cross section gradually increases from about 28 to 32 mils at one edge to about 33 to 40 mils at the other edge.

Process and intermediate sheet for forming shaped interlayer blanks

A process for forming discrete, shaped interlayer blanks comprising extruding thermoplastic melt into an endless, distortable straight-sided sheet having a gradient color band along one side, the melt forming the region of the sheet laterally of the color band extruding at a greater thickness than that forming the portion containing the color band, stretching the side of the sheet containing the region formed from the greater thickness melt more than the other side while extrusion continues to shape the sheet into an arcuate form of substantially uniform thickness having different radii along each edge, the edge of greater radius being on the side formed from the greater thickness melt, quenching the sheet to set the polymer, advancing the shaped sheet to a cutting station and cutting shaped quadrilateral sections out of the sheet having the gradient color band along one longitudinal side to form the blanks.

Process for forming shaped interlayer blanks

Apparatus for forming discrete, shaped interlayer blanks comprises, in combination, an extrusion die containing a slot for forming a sheet from thermoplastic melt, means associated with the die for causing a portion of the melt to exit the slot at a greater mass flow rate than that of the remainder of the melt exiting the slot, means adjacent the die for quenching the sheet immediately after forming and frusto-conical pull rolls for forwardly shaping the sheet into arcuate form, the surfaces of said rolls adjacent the edges of greatest circumference positioned to contact the portion of the sheet formed from the melt exiting the slot at the greater mass flow rate.

Apparatus for forming shaped interlayer blanks

The invention relates to a process and apparatus for producing a colored band in an extruded thermoplastic sheet. In the process, a probe is inserted in a sheet extrusion die manifold and a colored melt is injected into the polymer melt such that a sheet with an encapsulated colored band is obtained.

Extruding colored thermoplastic resin sheets

A process comprising winding polyvinylbutyral interlayer sheet at a controlled low tension reduces blocking at the core of the roll and minimizes stretch variations within the roll and storing the roll until use at a temperature below 15.degree. C.

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Amherst, MA, United States of America

Robert A Esposito