Patent GB-804291-A (GB)
Title: Production of improved thiourea-aldehyde resins having stable hydrophilic properties and the utilization thereof
IPC: C08G12/42
Filed: 1956-03-16
Abstract: Stable hydrophilic products are prepared from 1 mol. of thiourea and 2-3 mols. of water-soluble aldehyde by reaction of 1 mol. of the thiourea-aldehyde condensate with at least 0.4 mol. of a water-soluble monohydric alcohol at 40-65 DEG  C. and a pH of 4.5-5.6.  The thiourea-aldehyde condensate may be mixed with a urea-aldehyde condensate (0.6-7 parts by weight of urea/part of thiourea) in which case reaction is at 45 DEG  C. to the refluxing temperature and the pH is between 4 and 6.  Blending of condensates may take place before or after the reaction with alcohol.  Suitable aldehydes or formaldehyde, acetaldehyde, propionaldehyde and glyoxal. Suitable alcohols are methanol, ethanol, n- or isopropanol, or mixtures thereof.  The initial condensation is effected at pH above 7.  Reaction with the alcohol is stopped by addition of alkali before the stage when the reaction mixture would yield a precipitate or dilution with 50 times its volume of water at 20 DEG  C.  In examples 1-6, methanol, ethanol or isoproponal, thiourea and triethanolamine are heated to 50 DEG  C. and paraformaldehyde is added (pH 8.8). After 1 hour at 50-55 DEG  C., formic acid is added to reduce the pH to 5.1.  After another hour at 50-55 DEG  C. the pH is again adjusted to 8.0 and the solution cooled and stored.  In Example 7 a hydrophilic, partially polymerized dimethylol urea is blended with a product of the kind obtained in Examples 1-6.  Other examples illustrate minor changes in the reactants or the order of their mixing.  Catalysts for use with the products of the invention must contain halide salts.  Suitable substances mentioned are amine and alkylolamines, hydrochlorides or hydrobromides, e.g. the hydrochlorides of mixed isopropanolamines or of 2-methyl-2-aminopropanol-1, ammonium chloride or bromide, zinc bromide, magnesium chloride or bromide, calcium bromide, strontium chloride and barium bromide.  The products are useful in paper making, as chemical intermediates, in textile finishes and particularly for flame-retarding finishes especially on nylon net.ALSO:Stable hydrophilic thiourea-aldehyde-alcohol or thiourea - urea - aldehyde - alcohol condensates (see Group IV (a)) are used for stiffening nylon net and treating other fibrous textile materials, which may be composed of cotton, viscose rayon, wool, polyesters and acrylonitrile polymers and copolymers, and blends thereof. Catalysts which are halide salts, e.g. of metals, ammonia, amines or alkanolamines, are employed.  Specified aldehydes are formaldehyde, acetaldehyde, propionaldehyde and glyoxal. Substances producing formaldehyde may be used.  Specified alcohols are methanol, ethanol, n- or iso-propanol or mixtures thereof.  In Example 7 a syrup from thiourea, formaldehyde and methanol is blended with an aqueous dispersion of partially polymerized dimethylol urea.  Ammonium bromide is added as catalyst and the mixture is used to impregnate nylon net which is then treated at 340 DEG  F. for 1.2 minutes.  The Specification contains many other similar examples.