| abstract |
Bonding substrates with a partly crystalline adhesive, which is solid at room temp. and contains little or no water, comprises activating the adhesive by internal and/or external friction, bonding the substrates with the tackified adhesive between them and then leaving the bond to set in a few seconds to a few days. Also claimed are the adhesive and its prodn. Pref. the binder consists of: (a) at least one partly crystalline and (b) at least one amorphous and/or liquid polyester, polyester-amide or polyester-urethane with Mw = 1000-20000. The binder esp. is based on a polyurethane (mixt.) prepd. from (a) aliphatic or aromatic diisocyanate(s), esp. MDI, TDI, HDI, IPDI or more esp. TMXDI, (b) crystalline polyester- or polyether-diol(s), esp. polyethylene glycol with Mn = 200-40000, polytetrahydrofuran with Mn = 200-4000, an ethylene oxide/propylene oxide copolymer with Mn = 200-40000, esp. a PEG/PPG/PEG block copolymer contg. 10-80 wt.% and/or a polyester-diol, esp. polycaprolactone with Mn = 200-50000; (c) opt. diol(s) capable of forming ions, esp. carboxylates; (d) opt. tri- or higher polyol(s), e.g. glycerol and TMP; and (e) opt. hydrophobic diol(s), esp. PPG with Mn = 200-4000 and 1-100, esp. 2-50, more esp. 5-30 C alkandiols, using an NCO/OH molar ratio of 0.5-1.2, esp. 0.7-1. |