Hydroquinone → Urethane acrylate

Participants

Reaction Steps

First 700 parts of 535 molecule weight, polyhexyl orthophthalate were added to a glass resin kettle. A heating mantel was used to supply heat. The pot was also fitted with a thermometer and motorized stirrer. While stirring, the polyol was heated to 162° F. (72° C.) to degass at which temperature, 570 parts of isophorone diisocyanate (IPDI) were added. The temperature dropped to 130° F. (54° C.), but after 10 minutes began to rise again. Ten minutes later the material had exothermed to a peak temperature of 260° F. (127° C.) The prepolymer was allowed to react fully for 45 minutes with continuous stirring without heating. Two parts of hydroquinone were added next to stabilize the acrylate to be added in the subsequent phase of the reaction. The prepolymer was cooled further to 160° F. (71° C.) at which temperature, 367 parts of HEMA were added to completely react with the theoretical amount of free isocyanate available from the prepolymer. The temperature dropped to 150° F. (66° C.). A tin catalyst (T832) was added to the stirred material in the amount of 64 drops, the material exothermed to a peak temperature of 184° F. (84° C.) in 5 minutes. The material was then cooled to room temperature. After the acrylated urethane was allowed to sit at room temperature for 18 hours, an analysis for any residual amount of isocyanate was made. The % free NCO was 0.11. Four grams of butanol (a slight excess) were added to the reheated material to quench the remaining NCO groups. The viscous liquid was then poured into two glass quart jars which were then sealed.

Provenance & Evidence