Method of bonding permeable substrates with hot melt moisture cure adhesive having low viscosity and high green strength

A hot melt moisture cure polyurethane prepolymer composition comprising a composition prepared from:

• a) at least one polyol;
• b) at least one thermoplastic polyurethane that is substantially free of hard segments and having a number average molecular weight of greater than about 10,000 g/mole;
• and
• c) at least one isocyanate present at a sufficient concentration to impart moisture curing.

A method of preparing a hot melt moisture cure adhesive composition comprising:

• a) adding at least one fit polyol ingredient and at least one first isocyanate ingredient to a reaction vessel;
• b) polymering said at least one first polyol ingredient and said at least one isocyanate ingredient to form an OH or NCO terminated thermoplastic polyurethane ingredient having a number average molecular weight of at least about 10,000 g/mole, wherein ad thermoplastic polyurethane is substantially free of hard segments;
• c) adding at least one second polyol ingredient and at least one second isocyanate ingredient;
• and
• d) polymerizing said at least one second polyol ingredient and said at least one second isocyanate ingredient to form a hot melt moisture cure adhesive composition.

A hot melt moisture cure composition comprising:

• a) at least one polyol;
• b) at least one isocyanate present at a sufficient concentration to impart moisture curing;
• and
• c) at least one thermoplastic polyurethane that is substantially free of hard segments and having a number average molecular weight greater than 10,000 g/mole,
• wherein said composition has a viscosity of less than 60,000 cps at 250° F., a complex modulus of less than 1×107 dynes/cm2 after about 100 seconds of cooling, and a peel adhesion failure temperature of greater than about 250° F.

A hot melt moisture cure polyureathane prepolymer composition comprising:

• a) at least one polyol;
• b) at least one thermoplastic polyurethane that is substantially free of hard segments and having a number average molecular weight of greater than about 10,000 g/mole;
• and
• c) at least one isocyanate present at a sufficient concentration to impart moisture curing.