Moisture-curable one component coating composition

摘要

A moisture-hardening one-component coating material consists mainly of a polyisocyanate binder and opt. the usual paint additives etc. The binder is a mixt. of (A) 100 pts. wt. opt. carbodi-imide- or uretonimine-modified polyisocyanate(s) of the MDI series with a NCO content of 20-33 wt.%, (B) 40-150 pts. wt. NCO prepolymer with a NCO content of 1.5-12 wt.%, obtd. by reaction of (a) aromatic polyisocyanate(s) with a NCO content of 25-48.3 wt.% with (b) a deficiency of polyhydroxy component contg. (b1) ether, ester, thioether and/or carbonate gp.-contg. polyols(s) with a mol. wt. of 134-10,000, opt. in combination with (b2) up to 40 wt.% mono- to hexa-hydric alcohol(s) with a mol. wt. of 32-300 (other than b1), and (C) 10-90 pts. wt. aliphatic polyisocyanate component, contg. paint polyisocyanate(s) based on hexamethylenediisocyanate (HDI), with a viscosity of not greater than 3000 mPa.s at 23 degrees C, a NCO content of 17-24 wt.% and a monomeric HDI content of not more than 0.5 wt.%. Pref. (A) consists of a MDI-series polyisocyanate or mixt. thereof. (b) has a mean OH functionality of 2-4, and consists entirely of (b1) ether and/or ester gp.-contg. polyols with a mol. wt. of 500-4000, pref. (i) ester gp.-contg. polyether-polyols obtd. by reacting polyether-polyols with an OH no. of 200-600 with 8-24C monocarboxylic acid(s), opt. in combination with up to 20 COOH equiv.% of up to 10% polybasic carboxylic acid(s), and opt. (ii) ester gp.-free polyether-polyols. (C) consists of a paint polyisocyanate contg. allophanate, isocyanurate and/or uretdione gps., with a max. viscosity of 1000 mPa.s at 23 degrees C.