To obtain a urethdione group-containing polyaddition product which is used in polyurethane powder coating by reaction of isophorone diisocyanate- urethdioene with a di-secondary-diamine.
The reaction of (A) isophorone diisocyanate-urethdione (IPDI- urethdione) with (B) a di-secondary-diamine provides a urethdione containing polyaddition reaction product of formula I [R is a group of formula IF; R1 is the same as R or a 2-16C alicyclic or an aliphatic pendant or branched alkylene; R2 is a 1-12C alicyclic or aliphatic hydrocarbon or a group of formula III (R3 is a 1-14C hydrocarbon); n is 1-15]. This product preferably has a free- NCO content of 0.5-6wt.%, a urethdione group content of 1.3-1.7mmol/g and reversibly or irreversibly blocked NCO-group of 0-1.7mmol/g. A preferred adduct has its melting point fluctuating in a range from 60 to 170°C.
FUERITSUKUSU SHIYUMITSUTO
ERUMAARU BUORUFU
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