A Study on the Effects of Various Reaction Conditions on the Blocking Reactions of TDI and MDI in the Preparation of Polyurethane Varnishes

폴리우레탄 절연전선도료 제조시 TDI와 MDI의 Blocking 반응에 미치는 여러가지 반응조건의 영향에 관한 연구

  • 권석기 (홍익대학교 공업화학과) ;
  • 박내정 (홍익대학교 화학공학과) ;
  • 남윤기 (홍익대학교 화학공학과)
  • Received : 1997.01.08
  • Accepted : 1997.02.26
  • Published : 1997.04.10

Abstract

The effects of catalyst and blocking reagents(BR) on the blocking reactions of TDI and MDI in the preparation of polyurethane varnishes have been studied. It was found that certain types of catalysts, such as 1,4-diazabicyclo[2.2.2]octane(DABCO) and tetramethyl guanidine(TMG), were necessary to complete the NCO blocking reactions. Blocking rate of TMG was shown much faster than that of DABCO. Reactivity increased with the increase of TMG concentration, at least to the concentration of 1%. In case of DABCO, the 0.25% concentration of catalyst showed the highest reactivity. In order to study the steric effects of BR on the blocking reactions, phenol, p-cresol, m-cresol, o-cresol, 2,4-xylenol were used as blocking reagents. As expected, BR which has less steric hindrance showed higher reactivity. The increase in BR concentration and reaction temperature increased the productivity of polyurethanes in this reaction system.

Keywords

Acknowledgement

Supported by : 홍익대학교

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