Described herein is a moisture-curing polyurethane hot-melt adhesive including at least 80% by weight, based on a total weight of the moisture-curing polyurethane hot-melt adhesive, of isocyanate-terminated prepolymer obtainable by mixing diisocyanate (a) with compounds having at least two isocyanate-reactive groups (b) and reacting the mixture to form the isocyanate-terminated prepolymer, where the compounds having at least two isocyanate-reactive groups (b) include at least one polylactide (b1) obtainable by reacting lactide with a linear difunctional starter molecule having 2 to 20 carbon atoms and the isocyanate content of the isocyanate-terminated prepolymer is 1 to 5% by weight. Also described herein is a process for producing such a moisture-curing polyurethane hot-melt adhesive and a method of using the moisture-curing polyurethane hot-melt adhesive in bonding of substrates.

A one-component type polyurethane prepolymer composition comprises a reaction product formed through a reaction between reactants comprising (a) at least one polyisocyanate, and (b) a polyol blend comprising at least one bifunctional polyether polyol, wherein the bifunctional polyether polyol is a homopolymer of propylene oxide, homopolymer of butylene oxide, or copolymer of alkylene oxide, and has a number average molecular weight from 3000 g/mol to 9000 g/mol, and at least one trifunctional polyether polyol, wherein the trifunctional polyether polyol is a copolymer of alkylene oxide and end-capped with 10 wt % to 28 wt %, by the total weight of the trifunctional polyether polyol, of ethylene oxide, and has a number average molecular weight from 5000 g/mol to 8000 g/mol, wherein the bifunctional polyether polyol and the trifunctional polyether polyol are present in a parts by weight ratio from 4:1 to 2.5:1, and wherein the polyisocyanate and the polyol blend are present in a parts by weight ratio of from 1:7 to 1:2.5.

A one-component type polyurethane prepolymer composition comprises a reaction product formed through a reaction between reactants comprising (a) at least one polyisocyanate, and (b) a polyol blend comprising at least one bifunctional polyether polyol, wherein the bifunctional polyether polyol is a homopolymer of propylene oxide, homopolymer of butylene oxide, or copolymer of alkylene oxide, and has a number average molecular weight from 3000 g/mol to 9000 g/mol, and at least one trifunctional polyether polyol, wherein the trifunctional polyether polyol is a copolymer of alkylene oxide and end-capped with 10 wt % to 28 wt %, by the total weight of the trifunctional polyether polyol, of ethylene oxide, and has a number average molecular weight from 5000 g/mol to 8000 g/mol, wherein the bifunctional polyether polyol and the trifunctional polyether polyol are present in a parts by weight ratio from 4:1 to 2.5:1, and wherein the polyisocyanate and the polyol blend are present in a parts by weight ratio of from 1:7 to 1:2.5.

A poly(meth)acrylate urethane polymer, obtained from the reaction of at least one monomeric diisocyanate and a poly(meth)acrylate polyol having an OH number in the range from 50 to 200 mg KOH/g in an NCO/OH ratio of at least 3/1, followed by removal of a majority of the monomeric diisocyanate by means of a suitable separation method, wherein it has an NCO content in the range from 2.5% to 8% by weight, based on the poly(meth)acrylate urethane polymer, and a residual content of unconverted monomeric diisocyanates of not more than 0.5% by weight, and to the use thereof as additive and to moisture-curing polyurethane compositions.

A poly(meth)acrylate urethane polymer, obtained from the reaction of at least one monomeric diisocyanate and a poly(meth)acrylate polyol having an OH number in the range from 50 to 200 mg KOH/g in an NCO/OH ratio of at least 3/1, followed by removal of a majority of the monomeric diisocyanate by means of a suitable separation method, wherein it has an NCO content in the range from 2.5% to 8% by weight, based on the poly(meth)acrylate urethane polymer, and a residual content of unconverted monomeric diisocyanates of not more than 0.5% by weight, and to the use thereof as additive and to moisture-curing polyurethane compositions.

An embodiment of the present technology is an isocyanate-based adhesive used for a surface-treated crystalline thermoplastic resin base material, the isocyanate-based adhesive having a value represented by (JIS-A hardness)/(strength at break [MPa])×(elongation at break (%))/100 of 2.0 to 70 after being cured by being allowed to stand still under a condition at 23° C. and 50% RH for 3 days, and the crystalline thermoplastic resin base material having a value represented by (δ.sup.d/δ.sup.p+δ.sup.p) of 2.0 to 30.0. δ.sup.p=γ.sup.p−γ.sup.p0 and δ.sup.d=|γ.sup.d−γ.sup.d0|, γ.sup.p0 is a polar term of surface free energy before the surface treatment, γ.sup.p is a polar term of surface free energy after the surface treatment, γ.sup.d0 is a dispersion term of the surface free energy before the surface treatment, and γ.sup.d is a dispersion term of the surface free energy after the surface treatment.

An embodiment of the present technology is an isocyanate-based adhesive used for a surface-treated crystalline thermoplastic resin base material, the isocyanate-based adhesive having a value represented by (JIS-A hardness)/(strength at break [MPa])×(elongation at break (%))/100 of 2.0 to 70 after being cured by being allowed to stand still under a condition at 23° C. and 50% RH for 3 days, and the crystalline thermoplastic resin base material having a value represented by (δ.sup.d/δ.sup.p+δ.sup.p) of 2.0 to 30.0. δ.sup.p=γ.sup.p−γ.sup.p0 and δ.sup.d=|γ.sup.d−γ.sup.d0|, γ.sup.p0 is a polar term of surface free energy before the surface treatment, γ.sup.p is a polar term of surface free energy after the surface treatment, γ.sup.d0 is a dispersion term of the surface free energy before the surface treatment, and γ.sup.d is a dispersion term of the surface free energy after the surface treatment.

A moisture-curable composition, including: a) at least one polyurethane polymer P having isocyanate groups; b) at least one blocked polyamine BA having blocked, hydrolytically activatable amino groups; and c) at least one monoamine MA of formula (V),

##STR00001##

where R.sup.a represents a linear, cyclic, or branched alkyl or alkenyl radical or optionally substituted aryl radical with 1 to 12 C atoms and optionally including ether oxygen atoms; R.sup.b and R.sup.c either independently represent a rest R.sup.a or a hydrogen atom, where at least one of R.sup.b and R.sup.c is a hydrogen atom, or R.sup.b and R.sup.c together with the N atom of monoamine MA form an aldimine group that under influence of water hydrolyzes to a aldehyde and an amine R.sup.a—NH.sub.2; wherein polymer P is the reaction product of 2,4- and/or 2,6-toluylene diisocyanate (TDI) and at least one polyol, wherein the polyol has an average functionality of >2.

A moisture-curable composition, including: a) at least one polyurethane polymer P having isocyanate groups; b) at least one blocked polyamine BA having blocked, hydrolytically activatable amino groups; and c) at least one monoamine MA of formula (V),

##STR00001##

where R.sup.a represents a linear, cyclic, or branched alkyl or alkenyl radical or optionally substituted aryl radical with 1 to 12 C atoms and optionally including ether oxygen atoms; R.sup.b and R.sup.c either independently represent a rest R.sup.a or a hydrogen atom, where at least one of R.sup.b and R.sup.c is a hydrogen atom, or R.sup.b and R.sup.c together with the N atom of monoamine MA form an aldimine group that under influence of water hydrolyzes to a aldehyde and an amine R.sup.a—NH.sub.2; wherein polymer P is the reaction product of 2,4- and/or 2,6-toluylene diisocyanate (TDI) and at least one polyol, wherein the polyol has an average functionality of >2.

An one-part polyurethane composition, including: A) 15-75 wt.-% of at least one isocyanate-functional polyurethane polymer; B) 5-30 wt.-% of at least one organic thixotropy agent; C) 2-25 wt.-% of at least one plasticizer having viscosity of less than 500 mPa s, measured at 0° C. with cone-plate viscosimeter, shear rate 10 s.sup.−1, cone angle 1°, spindle 25-2, and cone tip-plate distance of 0.05 mm; D) 0-15 wt.-% of at least one solvent; E) 0-50 wt.-% of at least one filler; F) at least one catalyst for curing of polyurethane compositions; wherein isocyanate-functional polyurethane polymer has NCO content in range of 0.8%-2.5% by weight and is obtained from reaction of methylene diphenyl diisocyanate (MDI) and polyol in NCO/OH ratio of at least 3/1 and subsequent removal of non-reacted MDI; and polyol has viscosity, measured according to ASTM D4878-15 at 25° C., of less than 2000 mPa s; and isocyanate-functional polyurethane polymer has remaining content of MDI of at most 0.5% by weight.