| 摘要 |
The invention relates to a process for the controlled hardening of unsaturated polyester resins at temperatures of -5 DEG C. to +150 DEG C. using an organic peroxide initiator. According to the process of the invention an organic dyestuff of the general formula (I), <IMAGE> (I) wherein R1 stands for a group of the general formula (II), <IMAGE> (II) and in this formula R5 is a C1-4 alkyl group and n is an integer from 1 to 3, R2 and R3 each represent a C1-4 alkyl group, R4 stands for hydrogen, or R1 and R4 form together a group of the general formula (III), <IMAGE> (III) and in this formula R6, R7 and R8 each represent hydrogen or a C1-4 alkyl group and Z stands for oxygen or sulfur atom or a -NH- group, and X stands for chlorine or bromine, is admixed with the polyester resin and/or the organic peroxide in an amount of 0.001 to 0.05% by weight, calculated for the weight of the polyester resin. Using the method of the invention the composition and homogeneity of the polyester resin/additive mixtures can be observed easily and the progress of cross-linking can be monitored visually through characteristic colors and color changes, respectively. |
