Patent GB-383025-A (GB)
Title: A process for the production of condensation products
IPC: C08G12/04
Filed: 1931-10-19
Abstract: Resinous products which can be moulded under heat and pressure are prepared by the joint reaction of urea and urethane (or their derivatives) and thiourea with formaldehyde solution in the warm in the presence of an acid catalyst, the reaction being continued until a hydrophobe resin separates out on cooling.  Instead of urea and urethane (or their derivatives) and thiourea there may be used initial condensation products of these compounds with formaldehyde, e.g. mono- or di-methylol-urea or -thiourea, methylene-urea or -thiourea, and other initial urea- or thiourea-formaldehyde condensation products formed in an acid, neutral or alkaline medium, as well as monomethylolurethane, methylenediurethane, and anhydroformaldehyde-urethane; thiourethane may also be used instead of or in addition to urethane.  The reaction may be effected by dissolving urea, thiourea, and urethane in acid formaldehyde solution in the warm, or by adding an aqueous solution of urea, thiourea and urethane or their initial condensates to a boiling acid solution of formaldehyde, which may contain urea, or to a boiling acid initial condensation solution in the presence of an excess of formaldehyde, or by adding mixed initial condensates of urea, thiourea, and urethane to acidified boiling water together with excess of formaldehyde.  According to the examples (1) a solution of urea (0,75 mol.), thiourea (0,75 mol.), and urethane (0,5 mol.) in formaldehyde solution (2,2 mol.) is run into a boiling solution of urea (0,5 mol.) in formaldehyde solution (1,67 mol.) containing a little acetic acid: boiling is continued until resinous masses separate from a sample on cooling, and the reaction mixture is then mixed with a filler such as cellulose, sawdust, or asbestos, dried at a low temperature, if desired in vacuo, and then moulded under heat and pressure; (2) urea (1 mol.), thiourea (0,75 mol.), and urethane (0,25 mol.) are dissolved in formaldehyde solution (3 mol.) with a little citric acid, and the solution is boiled and worked up as in example (1). The Specification as open to inspection under Sect. 91 (3) (a) describes the production of resinous products by the joint reaction of urea and urethane (or their derivatives or initial condensation products, as defined above) with formaldehyde, thiourea being mentioned as an optional substitute for the whole or part of the urea, and the reaction being effected by any of the methods indicated above.  Examples are given in which:--(1) urea (1 mol.) and urethane (1 mol.) are dissolved in a solution of formaldehyde (2,6 mol.) containing a little acetic acid, and the solution is heated under reflux and worked up as in example (1) above; (2) a solution of urea (1,25 mol.) and urethane (0,6 mol.) in formaldehyde solution (1,5 mol.) is run slowly into a boiling solution of formaldehyde (1,67 mol.) containing a little acetic acid, and the product is worked up as indicated above; (3) a solution of urea (0,75 mol.) and urethane (0,6 mol.) in formaldehyde solution (1,5 mol.) is run slowly into a boiling solution of urea (0,5 mol.) in neutral or faintly alkaline formaldehyde solution (1,67 mol.) to which a little acetic acid has been added; after boiling, more acetic acid is added, boiling is continued, and the product is worked up as indicated above.  This subject-matter does not appear in the Specification as accepted.ALSO:Resinous products which can be moulded under heat and pressure are prepared by the joint reaction of urea and urethane (or their derivatives) and thiourea with formaldehyde solution in the warm in the presence of an acid catalyst, the reaction being continued until a hydrophobe resin separates out on cooling.  Instead of urea and urethane (or their derivatives) and thiourea there may be used initial condensation products of these compounds with formaldehyde, e.g. mono- or di-methylolurea or thiourea, methylene-urea or -thiourea, and other initial urea- or thiourea-formaldehyde condensation products formed in an acid, neutral or alkaline medium, as well as monomethylolurethane, methylenediurethane, and anhydroformaldehyde-urethane; thiourethane may also be used instead of or in addition to urethane.  According to examples: (1) a solution of urea (0.75 mol.), thiourea (0.75 mol.) and urethane (0.5 mol.) in formaldehyde solution (2.2 mol.) is run into a boiling solution of urea (0.5 mol.) in formaldehyde solution (1.67 mol.) containing a little acetic acid: boiling is continued until resinous masses separate from a sample on cooling, and the reaction mixture is then mixed with a filler such as cellulose, sawdust or asbestos, dried at a low temperature, if desired in vacuo, and then moulded under heat and pressure; (2) urea (1 mol.), thiourea (0.75 mol.) and urethane (0.25 mol.), are dissolved in formaldehyde solution (3 mol.) with a little citric acid, and the solution is boiled up as in example 1.  The Specification as open to inspection under Sect. 91 describes the production of resinous products by the joint reaction of urea and urethane (or their derivatives or initial condensation products, as defined above) with formaldehyde, thiourea being mentioned as an optional substitute for the whole or part of the urea.  Examples are given in which: (1) urea (1 mol.) and urethane (1 mol.) are dissolved in a solution of formaldehyde (2.6 mol.) containing a little acetic acid, and the solution is heated under reflux and worked up as in example (1) above; (2) a solution of urea (1.25 mol.) and urethane (0.6 mol.) in formaldehyde solution (1.5 mol.) is run slowly into a boiling solution of formaldehyde (1.67) mol. containing a little acetic acid, and the product is worked up as indicated above; (3) a solution of urea (0.75 mol.) and urethane (0.6 mol.) in formaldehyde solution (1.5 mol.) is run slowly into a boiling solution of urea (0.5 mol.) in neutral or faintly alkaline formaldehyde solution (1.67 mol.) to which a little acetic acid has been added; after boiling, more acetic acid is added, boiling is continued, and the product is worked up, as indicated above.  This subject-matter does not appear in the Specification as accepted.