Process and apparatus for the direct and continuous modification of polymer melts
AssigneeEMS-Inventa AG
InventorsWerner Stibal, Daniel Boni, Hans Luckert
Life of this patent
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Abstract
A process and an apparatus for the direct, continuous and flexible modification of polymer melts by branching off a brand melt stream from the main melt stream to be modified, dispersing the initially introduced additive in the melt in a specially designed twin-screw extruder, and subsequent recycling of the additive melt concentrate to the melt stream to be modified.
Claims15
A process for direct, continuous, introduction of at least one solid, difficultly soluble additive into a polymer melt, said process comprising dividing an initial main stream of said melt into a branch stream and an unmodified stream, dividing said branch stream into a reduced stream and a side stream,
- providing an extruder having a plurality of sequential zones which plurality comprises a metering zone, a melt entry zone, a wetting zone, a degassing zone, and a dispersing zone,
- metering said additive into said metering zone having a screw of reduced diameter compared to a larger diameter in said entry zone, said wetting zone, said degassing zone, and said dispersing zone, conveying said additive into said melt entry zone, feeding said reduced stream into said melt entry zone to form an initial mixture, conveying said initial mixture into said wetting zone to form a wetted mixture, conveying said wetted mixture into said degassing zone to remove volatiles from said wetted mixture to form a degassed mixture, conveying said degassed mixture into said dispersing zone to form a dispersed mixture, and
- discharging said dispersed mixture into a modified stream,
- introducing said dispersed mixture in said modified stream into said side stream and blending it therewith to form a final mixture.
A process for direct, continuous, introduction of at least one additive into a polymer melt, said process comprising dividing a branch stream (2) into a reduced stream (3) and a side stream (2'),
- providing an extruder (6) having a plurality of sequential zones which plurality comprises a metering zone (7) which is upstream of a melt entry zone (8), a wetting zone (9), a degassing zone (10), and a dispersing zone (11),
- metering said additive into said metering zone (7) having a screw of reduced diameter compared to a larger diameter in said entry zone (8), said wetting zone (9), said degassing zone (10), and said dispersing zone (11), conveying said additive into said entry zone (8), feeding said reduced stream (3) into said melt entry zone (8) to form an initial mixture, conveying said initial mixture into said wetting zone (9) to form a wetted mixture, conveying said wetted mixture into said degassing zone (10) to remove volatiles from said wetted mixture to form a degassed mixture, conveying said degassed mixture into said dispersing zone (11) to form a dispersed mixture, and
- discharging said dispersed mixture into a modified stream (14),
- introducing said dispersed mixture in said modified stream (14) into said side stream (2') and blending it therewith to form a final mixture.
Dependencies are inferred from the claim text.