Bonding of solid lignocellulosic material
AssigneeJohn Jansky
InventorJohn Stofko
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Abstract
Solid lignocellulosic material is bonded together by heating and pressing at a natural wood, pH by reacting sugars, starches or both in the presence of a catalyst capable of catalyzing transformation of the sugars and starches into a solid, insoluble in water, and an alkaline buffering agent if needed, for example to make waterproof plywood or composite products from particulate wood without hydrolytic degradation of the wood.
Claims30
A method of bonding solid lignocellulosic materials and thereby producing a waterproof bond, which comprises
- providing on a surface of said solid lignocellulosic material an adhesive-free bonding material consisting essentially of at least one sugar, starch or mixture thereof and an amount sufficient to catalyze transformation of the sugar or starch of a catalyst capable of transformation of the sugar or starch to cause waterproof bonding of adjacent lignocellulosic surfaces by means of the intermediate layer of adhesive-free bonding material therebetween, said catalyst being an alkaline salt or a mixture of an alkaline material and an acidic salt so that said bonding material will not decrease the pH after heating of the solid lignocellulosic material to below about 3.5, and
- pressing surfaces of the lignocellulosic material together at an elevated temperature and for a time sufficient to effect said bonding by said transformation reactions of the carbohydrate, and wherein the time, temperature and pressure are sufficient to produce a waterproof bond.
A method or providing a waterproof bond between solid lignocellulose materials, comprising:
- applying to said solid lignocellulose material an amount sufficient to effect bonding in the range of from 2-32 grams per 1000 cm.sup.2 of area of said lignocellulosic material of an adhesive-free bonding composition having a pH after heating of 3.5 to 5.5 and comprising sugar, starch or mixtures thereof, an alkaline buffering agent, and catalyst capable of catalyzing transformation of the sugar and starch to the surface of the lignocellulose material, the amount of catalyst being from 1 to 100% by weight of the carbohydrate;
- and
- pressing said solid lignocellulose material together at about 140.degree.-230.degree. C. at a pressure in the range of about 5-50 kg/cm.sup.2 for about 0.2 to 2 minutes per mm of thickness of said solid lignocellulosic material.
A method of bonding solid lignocellulosic materials and thereby producing a waterproof bond, which comprises
- providing on a surface of said solid lignocellulosic material an adhesive-free bonding material consisting essentially of at least one sugar, starch or mixture thereof and an amount sufficient to catalyze transformation of the sugar or starch of a catalyst capable of transformation of the sugar or starch to cause waterproof bonding of adjacent lignocellulosic surfaces, said catalyst being selected from alkaline salts or a mixture of an alkaline material and an acidic salt so that said bonding material will not significantly lower the pH of the bonded lignocellulosic material and
- pressing surfaces of the lignocellulosic material together at en elevated temperature and for a time sufficient to effect said bonding by said transformation reactions of the carbohydrate, and wherein the time, temperature and pressure are sufficient to produce a waterproof bond.
Dependencies are inferred from the claim text.