초록 ▼

The invention relates to a process for the production of highly concentrated and, surprisingly, viscosity-stable solutions of segmented polyurethane urea elastomers in highly polar solvents, such as dimethyl formamide and dimethyl acetamide, having little or no tendency to turn to paste, characteriz

The invention relates to a process for the production of highly concentrated and, surprisingly, viscosity-stable solutions of segmented polyurethane urea elastomers in highly polar solvents, such as dimethyl formamide and dimethyl acetamide, having little or no tendency to turn to paste, characterized by the use of certain primary and secondary cycloaliphatic monoamines or cycloaliphatic monisocyanates as chain-extending agents/blocking agents in the reaction of NCO prepolymers based on relatively high molecular weight dihydroxy compounds and (preferably aromatic) diisocyanates with aliphatic and and/or cycloaliphatic diamine chain-extending agents. The chain terminators according to the invention also show unexpected iprovements in the color of the elastomer solution and also in the stability of the end products, preferably filaments, to light and noxious gases. The invention also relates to elastomers of corresponding composition containing special terminators, preferably in the form of filaments, films or coatings showing improved stability to light and waste gases.

대표청구항 ▼

A process for the production of solutions of segmented polyurethane ureas by reaction of NCO prepolymers based on relatively high molecular weight dihydroxy compounds and excess quantities of diisocyanates with chain-extending agents terminated by NH-functional groups in the presence of monofunction

A process for the production of solutions of segmented polyurethane ureas by reaction of NCO prepolymers based on relatively high molecular weight dihydroxy compounds and excess quantities of diisocyanates with chain-extending agents terminated by NH-functional groups in the presence of monofunctional primary and/or secondary amines as chain terminators, characterized in that A1 to A4 [Figure] [Figure] [Figure] in which R=H, a linear or branched C1-4 alkyl radical or a cycloalkyl radical (preferably H, CH3, cyclohexyl) R1, R2, R3=H or a linear or branched C1-4 alkyl radical, although at least one substituent is alkyl unless R is already alkyl or cycloalkyl, are used as chain terminators in quantities of 0.01 to 10 equivalent-%, based on equivalents present in the NCO pre-polymer, and preferably in a quantity of 0.5 to 7 equivalent-%.