NITROGENOUS POLYCONDENSATES OF FORMALDEHYDE

摘要

1,216,275. Modified urea-formaldehyde condensates for stabilizing polyacetates. BADISCHE ANILIN- & SODA-FABRIK A.G. 19 April, 1968 [21 April, 1967 (2)], No. 18622/68. Headings C3P and C3R. Polycondensates useful as stabilizers of polyacetals against heat are prepared by heating (A) a diamide of a dicarboxylic acid having 4-18 C atoms and (B) an N : N1-alkyleneurea having 3-10 C atoms and/or an N : N1- distributed urea having alkyl, aryl or aralkyl groups of up to 8 C atoms as substituents with (C) formaldehyde in aqueous acid medium at 50‹-100‹ C., the molar ratio of (C) to (A) plus (B) being 1 to 2 : 1. Suitable starting materials are (A): azelaic, sebacic, decanedicarboxylic diamides, N : N1-dimethylsuberamide, adipamide and isophthalamide; (B): N : N1-ethylene - and - propylene - ureas, and N : N1 - dimethyl-, -diethyl-, -dibutyl-, -diphenyl-, -ditolyl- and -methyl-tolyl-ureas. The preferred molar ratio of (A) to (B) is 0À7-1À3 : 1. The formaldehyde (C) may be supplied as paraformaldehyde, trioxane or polyoxymethylene, or in the form of previously made N-methylol derivatives of (A) or (B). H 2 SO 4 , H 3 PO 4 or strongly acid ion exchangers are suitable polycondensation catalysts. The product is preferably neutralized and washed; the viscous aqueous solution may be diluted with e.g. 1 : 3-dioxolane, methanol or methoxyethanol for use in solution, or spray dried. They are suitable for stabilizing mouldable polyacetals, especially those containing at least 80 mol. per cent oxymethylene units, the remaining units being residues of e.g. ethylene oxides, propylene oxide, 1 : 3-dioxolane, 1:3- dioxane, 1:3-dioxacycloheptone or diglycol formal. Conventional phenolic or hydrazone antioxidants may also be added, or secondary aromatic amines, and also pigments and fillers. In Examples stabilizers are prepared from (Example 1-3) isophthalamide, N : N1- ethyleneurea and 30% formalin; in Examples 4 and 6 adipamide is used as (A); in Example 8 4-methoxy-5 : 5 dimethyl-N : N1-propyleneurea is used as (B). In Example 5 a trioxane (97%) dioxolane (3%) copolymer is stabilized with 0À2% of products of the invention, 0À25% of 2 : 21 - methylene - bis (4 - methyl - 6 - t - butylphenol) and 0À02% NaF.