Urethanes obtained from aromatic diisocyanates

Urethanes obtained from aromatic diisocyanates undergo slow oxidation in the presence of air and ligh t, causing discoloration, which is unacceptable in some applications. Polyurethanes obtained from aliphatic diisocyanates are color-stable, although it is necessary to add antioxidants and nv-stabilizers to the formulation to maintain the physical properties with... 

Aromatic copolyesters, 13 372 Aromatic diacyl peroxides, 14 283 Aromatic diisocyanates, urethanes obtained from, 25 462—463 Aromatic epoxies, 10 347-348 Aromatic ethers, 10 574 Aromatic fluorocarbon production, global, 11 871-872... 

The predominant configuration is trans 1,4 60%, with approximately 20% cis 1,4 and 20% vinyl 1 2, prepared by emulsion polymerization and with predominantly primary terminal hydroxyl groups of the allylic type. Hydroxyl functionality varies from 2-4 to 2-6 and gives high reactivity with aromatic diisocyanates. Room temperature cures are easily obtainable with typical urethane catalysts. Short-chain diols, fillers and process oils can also be used in their formulation to vary physical properties. 

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