DE2036714C2 - Process for the preparation of solvent-free and water-free liquid or solid solutions of methylolmelamines in alkyd resins containing hydroxyl groups - Google Patents

Description

On the state of the art and the references FR-PS 15 74 618, FR-PS 15 46 134 and paint and varnish, Vol. 76, Issue 5, May 1970, pp. 461-467, is referred to DE-PS 20 36 289 and there in column 1, line 33 to column 2, Reference made to line 49. Furthermore, it should be noted that none of these references Melamine and formaldehyde are mentioned.

The invention relates to the further development of the method for producing solvent and anhydrous liquid or solid solutions of methylolmelamines in alkyd resins containing hydroxyl groups, in which one methylolmelamines with 2 or more methylol groups in the molecule in hydroxyl groups Alkyd resins with a hydroxyl content of over 4% are finely divided, the resulting mixture in thinner Layer heated until solution of the methylolmelamine takes place with further condensation, and the temperature treatment then breaks off by cooling, according to patent 20 36 289, which is characterized in that instead of methylol melamines melamine and anhydrous formaldehyde, especially paraformaldehyde, are used will.

The particular advantage of the method according to the invention is that the separate operation for the production of methylolmelamines is omitted because condensation of melamine and formaldehyde too Methylolmelamines and dissolution of the latter in the hydroxyl-containing alkyd resins in one operation take place.

ίο The parts specified in the example are Parts by weight.

example

30 parts of pulverized melamine and 30 parts of pulverized paraformaldehyde are finely divided into 120 parts of a hydroxyl-containing alkyd resin, the preparation of which is described below, by means of a kneader and three-roller. The whitish mixture obtained is then adjusted to a to a temperature of 160 ⁰ C in a vacuum chamber of 50 torr located more heated roll mill given, which is regulated so that a layer thickness of the circulating mixture of about 0.1 mm results. Within a few minutes the mixture begins to become clear, which indicates the incipient condensation of the tetramethylolmelamine which is forming with simultaneous dissolution in the hydroxyl-containing alkyd resin. The temperature treatment is now interrupted by cooling in air. The viscous solution obtained dries in 60 minutes at 160 ° C. to give an elastic, non-tacky coating.

Production of the hydroxyl group-containing
Alkyd resin with a hydroxyl content above 4%

1 mol of 1,2-propylene glycol, 1 mol of triethylunglycol, 3.44 mol of glycerol, 1.33 mol of adipic acid and 1.15 mol of bezoic acid in the presence of 60 parts of xylene and 2 parts of zinc acetate reacted at 120-175 ° C, up to at least 95% of the theoretical amount of water are distilled off. The mixture is now allowed to cool below 140 ° C., and 1.3 mol of cyclohexane-1,2-dicarboxylic acid hydride are added and continues at 180-210 ° C with elimination of water up to the acid number of 7.5 µm.

Claims (2)

Patent claims: 1. Further development of the process for the production of solvent-free and water-free liquids or solid solutions of methylolmelamines in hydroxyl-containing alkyd resins, in which one Methylolmelamines with 2 or more methylol groups in the molecule in alkyd resins containing hydroxyl groups finely divided with a hydroxyl content of over 4%, the mixture obtained in this way in a thin layer heated until solution of the methylolmelamines takes place with further condensation, and the temperature treatment then breaks off by cooling, according to patent 2036289, characterized in, that melamine and anhydrous formaldehyde are used instead of methylol melamines will. 2. The method according to claim 1, characterized in that paraformaldehyde is used.