Moisture-curable polyurethane hot melt adhesive composition with oleic chemical resistance
A moisture-curable polyurethane hot melt adhesive composition having good oleic acid resistance, especially when exposed to 100% pure oleic acid under aging condition of 65° C. and 90% relative humidity, wherein the adhesive composition comprises, consists essentially of or consists of a moisture-curable polyurethane prepolymer, the prepolymer being a reaction product of at least one amorphous polyester polyol containing an aromatic group and at least one polyisocyanate, preferably at least one polyisocyanate containing an aromatic group, wherein the aromatic group is comprised in the polyurethane prepolymer in a content of no less than 23 wt. %, preferably no less than 25 wt. %, more preferably no less than 30 wt. %.
1 . A moisture-curable polyurethane hot melt adhesive composition comprising:
a polyurethane prepolymer,
wherein the polyurethane prepolymer is a reaction product of (i) at least two amorphous polyester polyols comprising an aromatic group and (ii) at least one polyisocyanate comprising an aromatic group,
wherein the polyurethane prepolymer comprises an aromatic group content greater than 30 wt. %, based on the total weight of the at least two amorphous polyester polyols and the at least one polyisocyanate, and
wherein the at least two amorphous polyester polyols as a whole have a glass transition temperature greater than −16° C. with a first amorphous polyester polyol having a glass transition temperature of from about 30° C. to about 60° C. and a second amorphous polyester polyol having a glass transition temperature of less than 10° C.
2 . The composition of claim 1 , wherein the at least two amorphous polyester polyols have a softening point less than 130° C.
3 . The composition of claim 1 , wherein the at least two amorphous polyester polyols have a molecular weight of from about 500 g/mol to about 10,000 g/mol.
4 . The composition of claim 1 , wherein the polyurethane prepolymer further comprises a polyether polyol.
5 . The composition of claim 4 , wherein the polyether polyol is present in an amount of less than 30 wt. %, based on the total weight of the polyurethane prepolymer.
6 . The composition of claim 1 , wherein the polyurethane prepolymer further comprises an amorphous polyester polyol having no aromatic group.
7 . The composition of claim 6 , wherein the amorphous polyester polyol having no aromatic group is present in an amount of less than 30 wt. %, based on the total weight of the polyurethane prepolymer.
8 . The composition of claim 1 , wherein the composition, when cured, exhibits a lap shear strength greater than 3 Mpa, when tested according to ASTM D1002 using ABS/ABS substrates and treated with 100% pure oleic acid.
9 . The composition of claim 1 , wherein the composition has a viscosity of less than 30,000 mPas at 110° C.
10 . The composition of claim 1 , wherein the at least two amorphous polyester polyols comprise a reaction product of (i) at least one polyacid and (ii) at least one polyol, wherein the at least one polyacid and/or the at least one polyol comprises an aromatic group.
11 . The composition of claim 1 , further comprising a catalyst.
12 . The composition of claim 1 , wherein the polyurethane prepolymer further comprises a crystalline polyester polyol present in an amount of less than 10 wt. %, based on the total weight of the polyurethane prepolymer.
13 . An article comprising:
a first substrate;
a cured adhesive comprising a cured product derived from the moisture-curable polyurethane hot melt adhesive composition of claim 1 ; and
a second substrate bonded to the first substrate using the cured adhesive.
14 . The article of claim 13 , wherein the article is selected from the group consisting of a wearable electronic device, a handheld electronic device, eye glasses, a phone, a tablet, a sound player, a remote control device, a mouse, a watch band, a pump for dispensing medicine, a headband, and any combination thereof.
15 . The composition of claim 1 , further comprising at least one additive selected from the group consisting of selected from a thermoplastic polymer, a tackifying agent, a plasticizer, a wax, a stabilizer, an antioxidant, talc, clay, silica and treated versions thereof, carbon black, mica, glass microspheres, polymer microspheres, an ultraviolet scavenger, an ultraviolet absorber, a pigment, a fluorescing agent, an odor mask, an adhesion promoter, a surfactant, a defoamer, and any combination thereof.
16 . The composition of claim 1 , wherein the molar ratio of hydroxy groups to isocyanate groups in the polyurethane prepolymer is from about 0.2:1 to about 0.9:1.
17 . The composition of claim 10 , wherein the at least one polyacid is selected from the group consisting of terephthalic acid, isophthalic acid, phthalic acid, methyl-hexahydrophthalic acid, methyl-tetrahydrophthalic acid, hexahydrophthalic acid, tetrahydrophthalic acid, maleic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, chlorendic acid, 1,2,4-butane-tricarboxylic acid, decanedicarboxylic acid, octadecanedicarboxylic acid, dimeric acid, dimerized fatty acids, trimeric fatty acids, fumaric acid, 1,3-cyclohexanedicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, anhydrides of the acids, and any combination thereof.
18 . The composition of claim 10 , wherein the at least one polyol is selected from the group consisting of ethylene glycol, propanediols, butanediols, butenediols, butynediol, pentanediols, pentenediols, pentynediols, hexanediols, octanediols, nonanediols, decanediols, neopentyl glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycols, propylene glycol, dipropylene glycol, tripropylene glycol, cyclohexanedimethanol, cyclohexanediol, dimer diols, bisphenol A, bisphenol F, hydrogenated bisphenol A, hydrogenated bisphenol F, glycerol, tetramethylene glycol, polytetramethylene glycol, 3-methyl-1,5-pentanediol, 2-methyl-1,8-octanediol, trimethylolpropane, pentaerythritol, sorbitol, glucose, and any combination thereof.
19 . A moisture-curable polyurethane hot melt adhesive composition comprising:
a polyurethane prepolymer,
wherein the polyurethane prepolymer is a reaction product of (i) amorphous hexanediol phthalate polyester diol, (ii) at least one amorphous polyester polyol comprising an aromatic group, and (iii) methylene diphenyl diisocyanate,
wherein the polyurethane prepolymer comprises an aromatic group content greater than 30 wt. %, based on the total weight of the amorphous hexanediol phthalate polyester diol, the at least one amorphous polyester polyol comprising the aromatic group, and the methylene diphenyl diisocyanate,
wherein the at least one amorphous polyester polyol has a glass transition temperature of from about 30° C. to about 60° C., and
wherein the amorphous hexanediol phthalate polyester diol and the at least one amorphous polyester polyol as a whole have a glass transition temperature greater than −16° C.
20 . A method of bonding two substrates, the method comprising:
providing a first substrate having a bonding surface and a second substrate having a bonding surface;
disposing the moisture-curable polyurethane hot melt adhesive composition of claim 1 in molten form on the first substrate bonding surface;
disposing the second substrate bonding surface on the moisture-curable polyurethane hot melt adhesive composition in molten form; and
cooling the disposed moisture-curable polyurethane hot melt adhesive composition to form a bond between the first substrate and the second substrate.