Mdf press technology

Abstract

The invention relates to a method for the production of a construction element manufactured from wood fibers, matchwood and/or sawdust, especially a board, comprising the following steps: adhesive is applied to the wood fibers, matchwood and/or sawdust; the wood fibers, matchwood and/or sawdust provided with adhesive are pressed to form a construction element, especially a board.

1 - 37 . (canceled)  
   
   
       38 . A method of manufacturing a construction element made from wood fibers, wood chips and/or sawdust comprising the steps of: 
 providing said wood fibers, wood chips and/or sawdust,    applying an adhesive to said wood fibers, wood chips and/or sawdust, and    pressing the wood fibers, wood chips and/or sawdust provided with said adhesive to form said construction element.    
   
   
       39 . The method of  claim 38 , wherein the step of providing said wood fibers, wood chips and/or sawdust includes providing at least some of said wood fibers, wood chips and/or sawdust as recycled wood fibers, wood chips and/or sawdust from the manufacture of said construction elements.  
   
   
       40 . The method of  claim 39 , further including the step of grinding said construction elements following said step of pressing, and wherein said recycled wood fibers, wood chips and/or sawdust are obtained from said grinding step.  
   
   
       41 . The method of  claim 38 , wherein the step of pressing is done at a temperature below 120° C.  
   
   
       42 . The method of  claim 38 , wherein the step of pressing is done at a temperature below 95° C.  
   
   
       43 . The method of  claim 38 , wherein the step of pressing is done at a temperature below 60° C.  
   
   
       44 . The method of  claim 38 , wherein said adhesive includes reactive resins, that may be hardened by cross-linking, selected from the group consisting of urea resins, melamine resins, acrylic resins, epoxy resins, polyester resins and mixtures thereof, and the step of pressing said wood fibers, wood chips and/or sawdust is free of substantial hardening of said adhesive.  
   
   
       45 . The method of  claim 44 , wherein said construction element comprises from less than about 10% up to about 35% adhesive by weight.  
   
   
       46 . The method of  claim 44 , wherein said wood fibers, wood chips and/or sawdust are broken down into solid and liquid components within a gas-tight system, the liquid components being separated from the solid components at a temperature in the range from about less than 50° C. up to about 90° C., said liquid components being added to said adhesive and applied to said solid components to form said construction element.  
   
   
       47 . The method of  claim 46 , wherein said adhesive is applied to said wood fibers, wood chips and/or sawdust at a temperature less than 100° C.  
   
   
       48 . The method of  claim 47 , further including the step of drying said wood fibers, wood chips and/or sawdust in a drying device at a drying temperature, and wherein the step of applying adhesive is performed remote of said drying device at a temperature cooler then said drying temperature.  
   
   
       49 . The method of  claim 48 , wherein the step of applying adhesive includes spraying an adhesive-gas mixture onto said wood fibers, wood chips and/or sawdust.  
   
   
       50 . The method of  claim 49 , wherein said adhesive is applied in an amount such that the resulting construction element contains from amount 45 kg/m 3  to 55 kg/m 3  of adhesive.  
   
   
       51 . The method of  claim 50 , wherein the step of applying adhesive includes placing said wood fibers, wood chips and/or sawdust onto a belt weighing machine and maintaining a constant weight ratio of said adhesive applied to said wood fibers, wood chips and/or sawdust.  
   
   
       52 . The method of  claim 51 , wherein said wood fibers, wood chips and/or sawdust provided with said adhesive are mixed and/or stirred in a cooled wall vessel.  
   
   
       53 . The method of  claim 52 , wherein the step of applying said adhesive includes initially forming a curtain or a mat of said wood fibers, wood chips and/or sawdust and applying the adhesive to said curtain or mat.  
   
   
       54 . The method of  claim 53 , further including applying air at a temperature of from about 40° C. to about 70° 0  C. together with said adhesive to said wood fibers, wood chips and/or sawdust.  
   
   
       55 . The method of  claim 54 , wherein the step of applying said adhesive includes also applying a hardening agent to said wood fibers, wood chips and/or sawdust.  
   
   
       56 . The method of  claim 55 , wherein said adhesive applied to said wood fibers, wood chips and/or sawdust has an outer surface that is hardened by cross-linking.  
   
   
       57 . The method of  claim 56 , further including laminating a finishing component to said construction element at an elevated temperature and completing the hardening by cross-linking of said adhesive.  
   
   
       58 . The method of  claim 44 , further including breaking down said wood fibers, wood chips and/or sawdust into solid components and liquid components, adding said liquid components to said adhesive, and applying said adhesive and liquid components to said wood fibers, wood chips and/or sawdust.  
   
   
       59 . The method of  claim 58 , further including cooling said liquid components by at least 30° C. and then applying the liquid components to said wood fibers, wood chips and/or sawdust.  
   
   
       60 . The method of  claim 58 , wherein said liquid components include lignin and hemicellulose, said liquid components comprising up to about 20 percent by weight of said adhesive.  
   
   
       61 . The method of  claim 58 , wherein synthetic material fibers and/or glass fibers are added to said wood fibers, wood chips and/or sawdust.  
   
   
       62 . The method of  claim 58 , wherein said adhesive applied to said wood fibers, wood chips and/or sawdust has an outer surface that is hardened by cross-linking.  
   
   
       63 . The method of  claim 62 , wherein said wood fibers, wood chips and/or sawdust are charged with steam immediately before pressing.  
   
   
       64 . The method of  claim 63 , wherein said recycled wood fibers, wood chips and/or sawdust are obtained from the manufacture of MDF and/or HDF boards for flooring panels and molded parts.  
   
   
       65 . The method of  claim 64 , wherein said pressed construction element is coated with at least paper provided with resins and compressed in a press at temperatures above 150° C. to laminate said paper to said construction element and complete said hardening by cross-linking said adhesive.  
   
   
       66 . A construction element made entirely or predominantly from wood fibers, wood chips and/or sawdust provided with adhesive and compressed together, said construction element containing from about 45 to about 55 kg/m 3  of said adhesive.  
   
   
       67 . The construction element of  claim 66 , wherein said adhesive comprises non-hardened resins.  
   
   
       68 . The construction element of  claim 67 , wherein said adhesive is selected from the group consisting of urea resins, melamine resins, acrylic resins, epoxy resins, polyester resins or mixtures of the same.  
   
   
       69 . The construction element of  claim 68 , wherein said construction element is a board.  
   
   
       70 . The construction element of  claim 69 , wherein said board consists essentially of wood fibers secured together with said adhesive.  
   
   
       71 . The construction element of  claim 68 , wherein said construction element contains more than 5 percent by weight of said sawdust.  
   
   
       72 . The construction element of  claim 68 , wherein said construction element has a density of at least 300 kg/m 3 .  
   
   
       73 . The construction element of  claim 68 , wherein said construction element has a density of less than 1500 kg/m 3 .  
   
   
       74 . A construction element produced in accordance with the method of  claim 38 .  
   
   
       75 . A laminate panel having a plurality of layers including a carrier board and one or more paper layers, said carrier board being produced in accordance with the method of  claim 38 .  
   
   
       76 . The laminate of  claim 75 , wherein said carrier board has a density greater than 1500 kg/m 3 .