Polyurethane compositions based on polyester block copolymers
AssigneeHenkel Kommanditgesellschaft auf Aktien
InventorsMichael Krebs, Christoph Lohr, Andreas Brenger, Ingolf Scheffler
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Abstract
The present invention relates to compositions comprising reaction products of a polyisocyanate with a polyester block copolymer and a process for the preparation thereof. These are suitable as a moisture-curing hot melt adhesive. The hot melt adhesive composition may optionally also comprise a reaction product of a polyisocyanate with a polyester polyol and/or a reaction product of a polyisocyanate with a polyether polyol. Such polyurethane hot melt adhesive compositions have good creep resistance and interfacial adhesion values on plastics and show very high strength values.
Claims8
A polyurethane hot melt adhesive composition comprising:
- (a) a reaction product of a polyisocyanate with a polyester block copolymer of the formula (I):
- HO—R2—O-A-O—R1—OH (I)
- (b) optionally a reaction product of a polyisocyanate with a polyester polyol and/or
- (c) optionally a reaction product of a polyisocyanate with a polyether polyol
- wherein A represents
- —R3—X—C(O)—R4—C(O)—X—R3—
- R1 and R2 independently represent (—(CH2)4—O—(CH2)4—)o, (—C3H6—O—C3H6—)o, (—C2H4—O—C2H4—)p, the radical of a polybutadiene, polycarbonate or a polycaprolactone or a combination thereof,
- X+R3 together represent a covalent bond or X represents O and R3 represents —(CH2)m—, and
- R4 represents a radical of a polyester, having carboxyl end groups, of a C4-C12 diol and a C6-C14 dicarboxylic acid after removal of the terminal carboxyl groups, and
- m=4 to 12, o=5-80 and p=5-80.
A composition as claimed in at least one of the preceding claims wherein the polyester polyol (b) is built from aliphatic dicarboxylic acids selected from adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecanedioic acid, dimer acid and 3,3-dimethylglutaric acid, aromatic dicarboxylic acids selected from terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid or mixtures thereof, and difunctional alcohols selected from ethylene glycol, propylene glycol, butanediol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, hexanediol, octanediol, decanediol, dodecanediol, neopentylglycol, dimer diol, hydroxypivalic acid-neopentylglycol or mixtures thereof.
A composition as claimed in at least one of the preceding claims wherein component (c) is a polypropylene glycol, polyethylene glycol, copolymer of ethylene oxide and propylene oxide or a poly(oxytetramethylene) glycol.
A composition as claimed in at least one of the preceding claims wherein it comprises
- 5 to 100 wt. % (a)
- 0 to 80 wt. % (b) and
- 0 to 80 wt. % (c).
Dependencies are inferred from the claim text.