GB892744A - Method of making moldable composition and product resulting therefrom - Google Patents

Abstract

A mouldable composition is made by heating an essentially dry mixture comprising comminuted lignocellulose (e.g. wood) and an agent capable of splitting at least a portion of the lignin from the lignocellulose while confining the mixture under superatmospheric pressure so as to retain gaseous products. Specified agents include steam, sulphur, ammonium hydroxide, sulphur dioxide, hydrogen sulphide, lime, formaldehyde, acetylene (or calcium carbide, which reacts with the moisture in the lignocellulose to yield acetylene), dibasic ammonium phosphate, lignin, dibasic ammonium phosphate plus lignin, steam plus sulphur plus ammonium hydroxide, steam plus sulphur plus sulphur dioxide, steam plus sulphur plus formaldehyde plus ammonium hydroxide, steam plus sulphur, sulphur plus copper sulphate, a finely divided solvent-extracted solid pine wood resin substantially free of wood rosin (e.g. that sold under the Registered Trade Mark "Vinsol") and combinations of these agents. Where steam is used, the reaction may be carried out at 300 DEG -550 DEG F. for 4-60 minutes, using saturated or superheated steam at 200-1,000 psig, and especially at 425 DEG -500 DEG F. using superheated steam. Sulphur may be used in an amount of up to 20% by weight, based on the lignocellulose. Ammonium hydroxide may be used in an amount of 2,5-10% by weight, on the same basis. Dibasic ammonium phosphate may be used in an amount of 2-4% by weight on the same basis, using a pressure of 200-1,000 psig and 300 DEG -550 DEG F., for 5-30 minutes. The reaction may be carried out in the presence of a nitrogenous base having a reactive hydrogen atom, e.g. aniline, and the reaction mixture using any of the above agents may also include zinc oxide, titanium oxide or manganese dioxide. In a preferred method an essentially dry mixture comprising comminuted lignocellulose, sulphur, a finelydivided solvent extracted solid pine wood resin substantially free of wood rosin, aniline, and zinc oxide is heated while confining the mixture under superatmospheric pressure so as to retain gaseous products. The essentially dry reaction mixture may be compressed so as to obtain a moulded product. Examples illustrate the use of sulphur, sulphur plus aqueous ammonium hydroxide, steam, dibasic ammonium phosphate plus lignin, sulphur plus copper sulphate, hydrogen sulphide, sulphur dioxide, aqueous ammonium hydroxide "Vinsol", "Vinsol" plus sulphur, "Vinsol" plus aniline plus sulphur, "Vinsol" plus aniline plus sulphur plus either zinc oxide or titanium oxide or manganese dioxide, "Vinsol" plus aniline plus sulphur plus zinc oxide plus calcium carbide, and "Vinsol" plus ammonium hydroxide plus sulphur plus zinc oxide. U.S.A. Specification 2,193,026 is referred to.ALSO:A mouldable composition is made by heating an essentially dry mixture comprising comminuted lignocellulose (e.g. wood) and an agent capable of splitting at least a portion of the lignin from the lignocellulose while confining the mixture under superatmospheric pressure so as to retain gaseous products. Specified agents include steam, sulphur, ammonium hydroxide, copper sulphate, sulphur dioxide, hydrogen sulphide, lime, formaldehyde, acetylene (or calcium carbide, which reacts with the moisture in the lignocellulose to yield acetylene), dibasic ammonium phosphate, lignin, a finely divided solvent extracted solid pine wood resin substantially free of wood rosin (e.g. that sold under the Registered Trade Mark "Vinsol") and combinations of these agents. The reaction may be carried out in the presence of a nitrogenous base having a reactive hydrogen atom, e.g. aniline, and the reaction mixture using any of the above agents may also include zinc oxide, titanium oxide or manganese dioxide. In a preferred method, an essentially dry mixture comprising comminuted lignocellulose, sulphur, a finely-divided, solvent-extracted, solid pine wood resin substantially free of wood rosin, aniline, and zinc oxide, is heated under superatmospheric pressure in a confined space. The essentially dry reaction mixture may be compressed so as to obtain a moulded product, and the reaction product, whether moulded or otherwise may be finely divided and moulded at an elevated temperature and pressure, e.g. 25-1,000 psi and 250-400 DEG F for 0,1-15 mins. U.S.A. Specification 2,193,026 is referred to.