GB261409A - Process for the production of porous artificial compositions - Google Patents

Abstract

261,409. Kunztharzfabrik & Dr. F. Pollak Ges. Nov. 14, 1925, [Convention date]. Urea-aldehyde condensation products.-Cloudy porous artificial masses are obtained by diluting with water the liquid initial condensation products of urea or its derivatives with formaldehyde until the water content is about 60-65 per cent, then forming a gel and allowing it to harden with inclusion of the water, and finally removing the water, first at a temperature below 30‹ C. and then at a higher temperature. An organic liquid such as alcohol may replace the water, but then at a lower specified concentration. It is stated to be possible to adjust the size of the pores. Liquid, solid, or fibrous organic or inorganic materials may be incorporated in the products during or after their manufacture. According to the examples, (1) a formaldehyde-fixing medium of the kind described in Specification 193,420 is added to a hydrophile condensation product prepared from urea and formaldehyde by the process described in Specification 213,567, and a little concentrated formic acid is stirred in; after standing some time, the mass is kept at 40‹ C. in a mould until it solidifies, when it is removed and hardened by keeping in a cool place, giving a white composition resembling meerschaum; by expelling in vacuo a proportion of water from the liquid condensation product before subjecting it to the preceding treatment, products are obtained which are less cloudy or even opalescent; (2) the hydrophobe condensation product prepared from urea and formaldehyde by the process described in Specifications 213,567 and 248,729 is mixed with alcohol as a dispersion medium, and after the addition of phosphoric acid, allowed to gelatinize in a mould at 50‹ C. ; the gel is then removed and allowed to stand at a temperature below 20‹ C. until the bulk of the alcohol and water have evaporated, when the mass is hardened by heat. Specifications 187,605 and 208,761 also are referred to. The Specification as open to inspection under Sect. 91 (3) (a) states that aldehydes in general may replace the formaldehyde, and that instead of acids may be employed acid salts, ammonium salts, neutral salts of strong acids with strong bases, albumen-precipitating agents and the like. This subject-matter does not appear in the Specification as accepted.