| 摘要 |
PURPOSE: A polyisocyanate polyaddition product is prepared which has a high hardness, low brittleness and coefficient of thermal expansion and improved light transmittance rate and light scattering rate. CONSTITUTION: Isocyanate is reacted with a compound having reactivity to the isocyanate at 20- 220 degree C for 0.5- 15 minutes in a 1- 20 MPa pressure of mold in the presence of or not catalyst, supplement agent and additives. Thus, 200 g of isocyanate and 30 g of polyol A such as polyether multivalent alcohol having 875 mg KOH/g of hydroxyl value to give isocyanate prepolymer in the presence of 0.001- 0.1 weight % of tin catalyst. 200 g Of the isocyanate prepolymer, 50 g of polyol A, 25 g of polyol B such as polyether multivalent alcohol having 770 mg KOH/g of hydroxyl value, 25 g of polyol C such as polyester multivalent alcohol of diethyl glycol and trimethylol propane having 60 mg KOH/g of hydroxyl value, are injected by RIM process in the presence of 1.0 g of tin and 1.25 g of 1,8-diazabicyclo£5,4,0|undec-7-ene to give the title product.
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