GB386991A - Fibrous compositions containing filler and binder substances and processes of making them - Google Patents

Abstract

Synthetic resins are employed as binders in the manufacture of paper pulp by thorough mixing of a filler, e.g. slate dust, finely ground silica, feldspar or sand, non-fibrous cellulose, diatomaceous earth, paper-makers' clay, pigments, &c. with sufficient organic binder in a plastic condition to produce a uniform distribution of the filler in the binder and kneading with heat, then adding wet fibrous material, e.g. Kraft, sulphite, soda, rag, or ground wood pulps, old news, mixed papers, clippings of sulphite papers to which may be added wool, asbestos, &c. until thoroughly mixed but discontinuing the mixing before the water has been driven out and while the fibres are incompletely coated and capable of further hydration, and adding water to reduce the mass to pulp. The resinous binder may be maintained uncured until after the pulp has been sheeted, e.g. the binder may be cured or hardened by the heated drying drums of the paper machine, or in a closed mould the material exhibiting plastic flow. In an example a resin is made by condensing cresylic acid, phenol, and formaldehyde in the presence of ammonia in a steam-jacketed vacuum kettle by heating to 90 DEG C. to start reaction and after 20 minutes maintaining the temperature at 100 DEG C. for 40 minutes, vacuum then being applied and the temperature raised to 110 DEG C. The resin is mixed with the filler in a Werner-Pfleiderer mixer and wet fibrous material added. Specifications 341,542 and 383,636, [both in Group VIII], are referred to.ALSO:In a process of making paper pulp by thorough mixing of a filler, e.g. slate dust, finely ground silica, feldspar or sand, non-fibrous cellulose, diatomaceous earth, paper makers' clay, pigments &c. with a binder, e.g. asphalts, bitumens, pitches, synthetic or natural resins, such as rosin or shellac, and kneading with heat, then adding fibrous material, e.g. Kraft, sulphite, soda, rag, or ground wood pulps old news, mixed papers, clippings of sulphite papers to which may be added wool, asbestos, &c. and water to reduce the mass to pulp, the resinous binder is maintained uncured until after the pulp has been sheeted. The binder may be cured by the heated drying drums of the paper-machine, or in a closed mould. In an example, a resin made from 39 lbs. of cresylic acid, 10 lbs. of phenol, 47 lbs. of formaldehyde and 4 lbs. of ammonia mixed in a steam-jacketted vacuum kettle is heated to 90 DEG C. to start reaction and after 20 minutes the temperature is maintained at 100 DEG C. for 40 minutes. Vacuum is then applied and the temperature raised to 110 DEG C. Specifications 341,542 and 383,636, [both in Group VIII], are referred to.