Boise Cascade Corporation

Officemax Incorporated

Lorence E Knowles

Erik J Van Kleek

Paul Dubelsten

Alister C Hume

Scott Bradley Gough

Heber D Layton

An apparatus and method for continuously forming composites comprising filler materials and thermoactive materials, particularly waste cellulosic materials and waste thermoplastics, are described. One embodiment of the apparatus includes either a batchwise or continuous mixer, such as a cyclone, for forming mixtures comprising filler and thermoactive material. The mixtures are conveyed to a continuous consolidation apparatus. Alternatively, the mixtures may be densified in a densifying apparatus before entering the consolidation apparatus. The consolidation apparatus includes a hot-gas distribution system having plural paired gas cells, such as rollers or hoods, for applying hot air to the charge. A first cell of each pair applies gas to the mixture. The second cell of each pair operates at a pressure less than that of the first cell, thereby creating a pressure differential across the charge. Certain embodiments of the apparatus include at least one set of baffles positioned adjacent a cell, at least one shroud positioned about a cell, or at least one set of baffles positioned adjacent a first cell and at least one shroud positioned about a second cell. The baffles and shrouds are used to eliminate or substantially reduce the amount of gas that is vented to the surrounding atmosphere. The method comprises continuously consolidating the mixtures by applying a hot, dry noncondensable gas to the mixture. Besides the filler material and the thermoactive material the mixture may further include materials selected from the group consisting of biocides, fungicides, fire retardants, conductive materials, pigments, water retardants, wax-like materials, coupling agents, crosslinking agents, and combinations thereof.

Apparatus and method for continuous formation of composites having filler and thermoactive materials, and products made by the method

A method for forming a product from cellulosic material and thermoactive material is described. A mat is formed from a mixture having a predetermined amount of cellulosic material and a predetermined amount of thermoplastic material. The mat is then consolidated and pressed to a predetermined final product thickness. At least a portion of a surface of the mat or product is then surface modified. Consolidating the mixture may include forming a first face layer, forming a core layer on the first face layer, and forming a second face layer on the core layer. Forming the core layer may include depositing mixtures of wood flakes and plastic flakes according to mixture flake size in successive layers such that the core layer has larger flakes adjacent the first face layer and adjacent the second face layer, and smaller flakes in a middle portion of the core layer. The method also can include fusing a sheet of plastic material to at least one surface of the mat, and surface modifying the plastic material. Grafting chemicals can be applied to surface modified mats, plastic material or products. A composite product also is described. One embodiment of the product comprises a first portion having a first core formed from a mixture comprising a cellulosic material and a thermoplastic material, and at least one face layer attached to the first core. The product also comprises a second portion bonded to the first portion. The second portion comprises a second core formed from a mixture comprising a cellulosic material and a thermoplastic material, and at least one face layer attached to the second core.

A method for forming a product from cellulosic material and thermoactive material is described. A mat is formed from a mixture having cellulosic material and thermoplastic material. The mat is consolidated and pressed to a final thickness. At least a portion of a surface of the mat or product may be surface modified. Consolidating the mixture may include forming a first face layer, forming a core layer on the first face layer, and forming a second face layer on the core layer. Forming the core layer may include depositing mixtures of wood flakes and plastic flakes according to mixture flake size in successive layers such that the core layer has larger flakes adjacent the first face layer and adjacent the second face layer, and smaller flakes in a middle portion of the core layer. Consolidation can occur as a mat or composite moves through a hot-gas consolidation zone.

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Springfield, OR, United States of America

Lorence E Knowles