Abstract: Heat-curable, aqueous synthetic resin mixtures for coating woodworking materials, based on etherified melamine/formaldehyde condensates and aqueous synthetic resin dispersions, a process for the preparation of these mixtures and their use for coating woodworking materials.

Abstract: An aqueous resin solution for the impregnation of paper webs contains 2-40 parts by weight of a polyurea composed of urea and of a polyamine per 100 parts by weight of a melamine/formaldehyde precondensate. The impregnated paper webs are suitable for coating woodbase materials, especially chipboard.

Abstract: Amino resin solutions having an electrical conductivity of <100 .mu.S/cm for impregnating paper are obtainable byA) methylolation of melamine with aqueous formaldehyde in a molar ratio of from 1:2 to 1:5 in the presence of a tertiary organic amine at a pH of from 7 to 12,B) etherification with a molar excess, based on the methylol groups, of a C.sub.1 -C.sub.4 -alcohol in the presence of an unsubstituted or substituted dicarboxylic acid and/or polycarboxylic acid at a pH of from 3 to 6,C) neutralization of the reaction mixture with an inorganic base and removal of the volatile components by distillation, except for a water content of <10% by weight, based on the reaction mixture, andD) addition of a C.sub.1 -C.sub.4 -alcohol to give a solids content of from 40 to 90% by weight, based on the amino resin solution, and removal of insoluble components by filtration.

Abstract: In the proposed pulverulent aminoplast adhesive resin for wood-base materials having a low formaldehyde emission, the resin is a mixture of(a) from 40 to 90 parts by weight of a urea/formaldehyde resin having a molar ratio of urea to formaldehyde of from 1:1.4 to 1:2,(b) from 2 to 20 parts by weight of melamine, some or all of which may have been reacted with the urea/formaldehyde resin component,(c) from 2 to 20 parts by weight of urea and(d) if required, from 0.1 to 10 parts by weight of an agent for increasing the shelf life,together with not more than 10 parts by weight of water and, if required, not more than 10 parts by weight of other additives, the numbers of parts by weight of the components summing to 100.In the process for the preparation of the pulverulent aminoplast adhesive resin, powdered melamine is stirred into a solution of the urea/formaldehyde resin, urea is added and the solution is spray dried.

Abstract: In a proposed aminoplast adhesive resin powder for wood-based materials, which eliminates little formaldehyde, the resin is a mixture of(a) from 40 to 75 parts by weight of a urea/formaldehyde resin having a molar ratio of urea to formaldehyde of from 1:1.4 to 1:2,(b) from 10 to 20 parts by weight of a melamine/formaldehyde resin having a molar ratio of melamine to formaldehyde of from 1:1.3 to 1:3,(c) from 15 to 25 parts by weight of milled urea and(d) from 0.3 to 5 parts by weight of a flow improver, as well as up to 10 parts by weight of water and, if required, up to 10 parts by weight of other additives, the number of parts by weight of the components summing to 100.

Abstract: A process for bonding lignocellulose raw materials using an isocyanate group-containing urethane-modified diphenylmethane diisocyanate mixture having a viscosity of 120 to 1000 mPas at 25.degree. C. and an isocyanate content of 15 to 33.6 percent by weight which is obtained by reacting a diphenylmethane diisocyanate mixture containing 10 to 75 percent by weight of 2,4'-diphenylmethane diisocyanate with 0.05 to 0.5 hydroxyl equivalents of a polyol per equivalent isocyanate group.

Abstract: An aqueous solution of a resin glue comprising formaldehyde, urea, melamine and phenol is obtained when phenol, formaldehyde and not more than 0.35 mole of an alkali metal bisulfite per mole of phenol are reacted to give a phenol-formaldehyde condensate, formaldehyde and urea in a molar ratio of not more than 2.5 are reacted to give a urea-formaldehyde condensate, and the reaction products are in turn reacted with melamine and formaldehyde.

Abstract: Aqueous polyisocyanate emulsions are prepared by employing water-soluble polyamides as emulsification agents.

Abstract: Condensates containing urea and formaldehyde in a molar ratio of from 1:2.5 to 1:4.5 are converted into wood glue by allowing the viscosity to increase at a pH of from 1 to 3 and at only slightly elevated temperature and then adding urea at a pH of 7 to 9.