Blocked poly-isocyanurate adhesion promoter for PVC plastisols - derived from aliphatic, alicyclic, araliphatic or hydrated aromatic di-isocyanate and and styrene-substd. phenol

摘要

Blocked polyisocyanurate of formula (I) is claimed (where X, Y, Z = residue of an aliphatic, alicyclic or aromatic di-isocyanate in which the NCO gps. are not directly bonded to the aromatic ring, or a hydrated aromatic di-isocyanate; n = 1-10). PVC plastisol compsn. (II) contains PVC resin, plasticiser, cpd. (I) as adhesion promoter, and catalyst(s) which accelerate the dissociation of (I), namely Bu2Sn(OAc)2, Zn octoate, Sn octoate, Bu2Sn diamaleate or triethylenediamine. Pref., (II) contains (I) (where X = Y = Z = hexamethylene). (I) is produced (a) by converting a di-isocyanate (e.g. hexamethylenedi-isocyanate (HDI), TMDI, IPDI, XDI, hydrated MDI) into the corresp. isocyanurate with 3 terminal NCO gps. and then reacting this prod. with excess styrene-substd. phenol of formula Ph-CHMe-C6H4-OH (III), or (b) by reacting the same di-isocyanates with (III) and converting the blocked di-isocyanate obtd. into (I), using the same catalysts as in (a) (e.g., KOAc, Na stearate, quat. ammonium cpds., etc.). USE/ADVANTAGE - (II) are used esp. as sealants for motor bodywork. W.r.t. prior-art PVC plastisol compsns., (II) have excellent adhesion (e.g. to galvanised metal), even when cured at low temp. (110-130 deg.C), combined with good resistance to yellowing.