Cellular moulded plastics for e.g. shoe sole prodn. - by reaction of polyether di- and tri:ol(s) with isocyanate semi-prepolymer, using water as sole blowing agent

摘要

The prodn. of cellular moulded plastics (I) based on polyether-polyurethanes, by foam-moulding a mixt. of (a) high-mol. wt. polyether-polyol component, (b) polyisocyanate, (c) chain extenders, (d) blowing agents, (e) activators and opt. (f) other additives etc., with isocyanate index = 70-130; the novelty is that; (i) component (a) has mean OH functionality 2.02.2.95, and contains (aa) polyetherdiol(s) with OH no. 21-112, obtd. by propoxylation of a difunctional starter, followed b y ethoxylation, with wt. ratio PO:EO = (60:40)-85:15), and (ab) polyether-triol(s) with OH no. 21-56, obtd. from a trifunctional starter as above, with wt. ratio PO:EO as above, and opt. contg. up to 20 wt.% (w.r.t. total a) fillers based on S/AN copolymers, polyureas or polyhydrazo-carbonamides, (ii) component (b) is a semi-prepolymer contg. 10-25 wt.% NCO gps., prepd. by reaction of (ba) 4,4'-MDI with (bb) a polyether with OH no. 21-112 and OH functionality 2.0-2.5, comprising polyether-diol(s) obtd. by propoxylation of a difunctional starter followed by ethoxylation with up to 30 wt.%EO, or a mixt. thereof with similarly alkoxylated polyether-triol(s) based on trifunctional starters; up to 10 wt.% liquefied MDI (liquefied with PPG of mol. wt. 134-700 and/or by partial carbodi-imidation of NCO gps.) is added to (ba) before reaction or to the reaction prod., (iii) component (c) is ethane-1,2-diol and/or butane-1,4-diol (230-1100 OH equiv.% w.r.t. OH gps. in a), (iv) water is the sole blowing agent. USE/ADVANTAGE - The process enables the prodn. of medium-hard PU foam mouldings, with mechanical properties, etc. equiv. to those obtd. by prior-art processes, without using CFC or other organic blowing agents.