Advanced engineering resin and wood fiber composite
First Claim
1. A resin and fiber composite thermoplastic pellet, capable of formation into a structural member, which pellet comprises a thermoplastic extrudate having a width of about 0.1 to 5 millimeters and a length of about 0.1 to 10 millimeters, the thermoplastic extrudate consisting essentially of:
- (a) a continuous phase comprising a thermoplastic engineering resin, comprising repeating monomer units substantially free of vinyl chloride, the resin having a surface energy greater than 40 dynes/cm, a processing temperature less than 250°
C., and a moisture sensitivity such that the resin does not have a substantial reduction in melt index or molecular weight during processing in the presence of water; and
(b) an effective amount of wood fiber having a minimum dimension of about 0.1 millimeter and a minimum aspect ratio of about 1.5 to provide structural properties to the composite;
wherein the resin and wood fiber are mixed at elevated temperatures and pressure such that an intimate admixture is formed, the wood fibers are dispersed in the a continuous thermoplastic phase, the pellet is a recyclable thermoplastic and the composite has a Young'"'"'s modulus of at least 500,000 psi.
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Accused Products
Abstract
The invention relates to a composition including an engineering resin and wood fiber composite that can be used in the form of a linear extrudate or thermoplastic pellet used to manufacture structural members. The resin/wood fiber composite structural members can be manufactured in an extrusion process or an injection molding process as a linear extrudate or pellet that can have a cross-section of any arbitrary shape, or can be a regular geometric shape and have a volume of at least about 12 mm3. Preferably the pellet is a right cylindrical pellet having a minimum radius of about 1.5 mm and a minimum length of 1 mm weighing at least 14 mg. The invention also relates to the environmentally sensitive recycle of waste streams. The resin/wood fiber composite can contain an intentional recycle of a waste stream including polymer flakes, polymer particles, or wood fiber as well as adhesives, paint, or preservatives. The initial mixing step before extrusion of the composite material insures substantial mixing and melt contact between molten resin and wood fiber. The extruded pellet includes a useful proportion of resin, wood fiber and water. During the extrusion, water is removed intentionally to dry the material to a maximum water content of less than about 10 wt % based on the pellet weight. The pellet is then introduced into an extruder or injection molding apparatus wherein the composite pellet material is shaped into a useful cross-section.
261 Citations
51 Claims
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1. A resin and fiber composite thermoplastic pellet, capable of formation into a structural member, which pellet comprises a thermoplastic extrudate having a width of about 0.1 to 5 millimeters and a length of about 0.1 to 10 millimeters, the thermoplastic extrudate consisting essentially of:
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(a) a continuous phase comprising a thermoplastic engineering resin, comprising repeating monomer units substantially free of vinyl chloride, the resin having a surface energy greater than 40 dynes/cm, a processing temperature less than 250°
C., and a moisture sensitivity such that the resin does not have a substantial reduction in melt index or molecular weight during processing in the presence of water; and(b) an effective amount of wood fiber having a minimum dimension of about 0.1 millimeter and a minimum aspect ratio of about 1.5 to provide structural properties to the composite; wherein the resin and wood fiber are mixed at elevated temperatures and pressure such that an intimate admixture is formed, the wood fibers are dispersed in the a continuous thermoplastic phase, the pellet is a recyclable thermoplastic and the composite has a Young'"'"'s modulus of at least 500,000 psi. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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28. A resin and fiber thermoplastic composite, capable of formation into a structural member, which composite comprises a thermoplastic engineering resin and fiber, the composite consisting essentially of:
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(a) a continuous phase of a thermoplastic engineering resin, comprising repeating monomer units substantially free of vinyl chloride, the resin having a surface energy greater than 40 dynes/cm, a processing temperature less than 250°
C., and a moisture sensitivity such that the resin does not have a substantial reduction in either melt index or molecular weight during processing in the presence of water; and(b) an effective amount of wood fiber having a minimum dimension of about 0.1 millimeter and a minimum aspect ratio of about 1.5 to provide structural properties to the composite; wherein the resin and wood fiber are mixed at elevated temperatures and pressure such that an intimate admixture is formed, the wood fibers disperse throughout a continuous thermoplastic resin phase, the pellet is recyclable and the composite has a Young'"'"'s modulus of at least 500,000 psi. - View Dependent Claims (29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51)
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Specification