GB482894A - Improvements in or relating to the production of mouldable articles from lignin derivative material and fibrous filler - Google Patents

Abstract

482,894. Fibrous boards &c. MEAD CORPORATION. Oct. 6, 1936, No. 27139. Convention date, Oct. 25, 1935. [Class 96] Mouldable articles are produced by mixing intimately with agitation, fibrous material in water with finely divided lignin derivative material obtained from digestion liquor used in the preparation of paper pulp, flowing the mixture containing, e.g. 97 per cent of water on to a former and withdrawing water, e.g. by suction to form a sheet or other article which is pressed to desired form and thickness and dried at a temperature below the fixing temperature of the lignin derivative material. Finely-divided, substantially-pure, ash-free, lignin residues are obtained from sulphite, sulphate, soda &c. digestion of woody materials, as by precipitation by an acid such as carbon dioxide in the case of a black liquor from a soda cask. The fibrous material may be cotton linters, alpha-cellulose, ground wood, asbestos or pyrophillite. The lignin residues are precipitated at pH=7À8 to 9 and the suspension heated to about 60‹ C. to coagulate the particles cooled, filtered, washed, treated with excess acid, e.g. sulphuric, again washed. The dried material may be granulated. It may be used with phenol-formaldehyde or urea-formaldehyde resins, pigments, e.g. carbon or nubian black, dyes &c., alum &c. being added during or after beating. Size may be added to the pulp in the usual way. The boards &c. are dried at low temperature compacted at, e.g. 10,000 lb. per square inch and moulded at 310 to 350‹F. Furfurol may be added to control the fusing temperature of the lignin derivative. The board may be surfaced with material of superior quality applied before final moulding, embossing, &c. The moulded board may be used for automobile bodies.