POLYCONDENSATION PRODUCTS OF N, N'-DIMETHYLOL RESIN FINISHING AGENTS

Abstract

Chemical constitutions, i.e. N-CH2OH, N-CH2OCH2-N, and N-CH2-N, of the polycondensation products of dimethylol ethylene urea (DMEU) and dimethylol propylene urea (DMPU) prepared under the various curing conditions were studied. N-CH2OH and free CH2O in the reaction products were determined separately by the application of the KCN method. Contents of N-CH2OCH2-N and N-CH2-N were determined separately from the difference of their hydrolysis rates to acetic acid, and confirmed by the NMR method. The kinetics in these hydrolyses were also studied.Chemical constitutions of the polycondensation products were affected remarkably by their curing time and temperature. With changing the curing time at 120°C, N-CH2OCH2-N was formed rapidly at first, and then decreased with time, while contents of N-CH2-N and free CH2O increased at about the same rate with time. It was suggested that the N-CH2OH in DMPU or DMEU was rapidly consumed for the formation of N-CH2OCH2-N, which decomposed gradually into N-CH2-N and free CH2O in the polycondensation. The similar tendencies for the formation of N-CH2OCH2-N, N-CH2-N and free CH2O were also found with changing the curing temperature for 30min. Degrees of polycondensation of DMPU and DMEU oligomers, in both cases, reached 9-10 in maximum. It was also found that Zn(NO3)2 showed excellent catalytic action leading to the formation of N-CH2-N in considerable amounts, but MgCl2 only affected the formation of N-CH2OCH2-N, and Mg(CH3COO)2 had almost no catalytic action under a curing condition, 120°C, 30min.