Multi-component coextrusion
First Claim
1. A multi-component, longitudinally continuous extrusion suitable for use in the fenestration, decking and remodeling industries, comprising:
- a first, high density composite member consisting of a thermoplastic component and a cellulosic fiber component extruded from a primary extruder into an extrusion die, wherein the first member has inner and outer sidewalls defining a high density, thin wall extrusion having at least one enclosed, hollow interior compartment; and
, a second, low density foamed member consisting of a foamed thermoplastic polymer, coextruded with the first member in a molten state from a secondary extruder into the extrusion die so as to be laterally coextensive with and molecularly bonded to one of the sidewalls of the first member.
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Accused Products
Abstract
A multi-component composite extrusion includes various combinations of a hollow, high density profile filled in with a foamed, thermoplastic core. A further low density foamed profile can alternately surround the high density, hollow component. A capstock can be provided on either embodiment of the multi-component extrusion. All of the components are preferably substantially simultaneously extruded in a single multi-plate extrusion die, so that the various components are substantially laterally coextensive with one another and molecularly bonded to the adjacent component. The thin wall, high density component and the adjacent low density foamed thermoplastic component may optionally be provided with substantial wood fiber content to alter the macroscopic properties of the resulting multi-component extrusion. The extrusion has utility in the fenestration, decking, and remodeling industries. The method disclosed for making the extrusion permits the extrusion designer to vary the type of thermoplastic material used with respect to each component and the presence or absence of wood fiber in the components to vary the macroscopic properties of the entire composite extrusion, surface characteristics of the extrusion, and weatherability of the extrusion.
71 Citations
19 Claims
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1. A multi-component, longitudinally continuous extrusion suitable for use in the fenestration, decking and remodeling industries, comprising:
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a first, high density composite member consisting of a thermoplastic component and a cellulosic fiber component extruded from a primary extruder into an extrusion die, wherein the first member has inner and outer sidewalls defining a high density, thin wall extrusion having at least one enclosed, hollow interior compartment; and
,a second, low density foamed member consisting of a foamed thermoplastic polymer, coextruded with the first member in a molten state from a secondary extruder into the extrusion die so as to be laterally coextensive with and molecularly bonded to one of the sidewalls of the first member. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A multi-plate extrusion die of the type having a plurality of die plates sequentially positioned so as to define upstream and downstream directions, comprising:
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an introductory plate generally defining a primary aperture for passage therethrough of a primary extrudate, the primary aperture extending longitudinally through substantially each die plate of the extrusion die;
a mandrel plate downstream of the introductory plate and fluidly connected thereto for receipt of the primary extrudate and a secondary extrudate, having a first elongated mandrel substantially suspended therein by first support means for supporting the first mandrel in a spaced apart relationship within the primary aperture, wherein the first mandrel is substantially hollow and has a second mandrel substantially suspended therein by second support means for supporting the second mandrel in a spaced apart relationship within the first mandrel so as to form an elongated hollow, interstitial void between the first and second mandrels; and
,a secondary plate positioned between the introductory and mandrel plates having means for introducing the second extrudate into the interstitial void, whereby an elongated final extrudate having at least two different longitudinally continuous, molecularly bonded thermoplastic components can exit the mandrel plate. - View Dependent Claims (13, 14)
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15. A method of making a multi-component, longitudinally continuous extrusion suitable for use in the fenestration, decking and remodeling industries with a multi-plate extrusion die of the type having a plurality of die plates sequentially positioned so as to define upstream and downstream directions, comprising the steps of:
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preparing a thermoplastic primary extrudate and a thermoplastic secondary extrudate;
introducing the primary extrudate in a molten state into an introductory plate generally defining a primary aperture for passage therethrough of the primary extrudate, wherein the primary aperture extends longitudinally through substantially each die plate of the extrusion die;
positioning a mandrel plate downstream of and fluidly connected to the introductory plate, wherein the mandrel plate has a first elongated mandrel suspended in a spaced apart relationship within the primary aperture and wherein the first mandrel is substantially hollow and has a second mandrel substantially suspended therein in a spaced apart relationship within the first mandrel so as to form an elongated, hollow, interstitial void between the first and second mandrels; and
,introducing the secondary extrudate in a molten state into the interstitial void, whereby an elongated final extrudate having at least two different longitudinally continuous, molecularly bonded thermoplastic components exit the mandrel plate. - View Dependent Claims (16, 17, 18, 19)
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Specification