Reactive hot-melt adhesive compositions with improved green strength
A moisture-reactive hot-melt composition, useful as an adhesive, is provided that has improved balance of open time and green strength. In particular, the composition is made from a polyol, a polyisocyante, and an acrylic polymer. Also provided are a method for making such compositions and a method for using such compositions for bonding substrates.
1. A moisture-reactive hot-melt polymer composition formed by admixing components comprising at least one polyol, at least one polyisocyanate, and at least one acrylic polymer having tertiary-alkyl amide functionality, wherein said acrylic polymer having tertiary alkyl amide functionality has glass transition temperature of 20° C. to 120° C., and wherein said acrylic polymer having tertiary alkyl amide functionality has no hydroxyl functionality.
2. The composition of claim 1 , wherein said acrylic polymer is 1 to 90 weight percent of said composition, based on the total weight of said composition.
3. The composition of claim 1 , wherein said acrylic polymer includes at least one tertiary-alkyl amide functional monomer selected from the group consisting of N-tert-butylacrylamide, N-tert-butylmethacrylamide, 2-acrylamido 2-methylpropane sulfonic acid, diacetone acrylamide, diacetone methacrylamide, N-tert-octyl acrylamide, N-tert-octyl methacrylamide, and mixtures thereof.
4. The composition of claim 1 , wherein said polyol comprises at least one polyester polyol and at least one polyether polyol.
5. The composition of claim 1 , wherein said acrylic polymer is 1 to 90 weight percent of said composition, based on the total weight of said composition; wherein said acrylic polymer includes at least one tertiary-alkyl amide functional monomer selected from the group consisting of N-tert-butylacrylamide, N-tert-butylmethacrylamide, 2-acrylamido 2-methylpropane sulfonic acid, diacetone acrylamide, diacetone methacrylamide, N-tert-octyl acrylamide, N-tert-octyl methacrylamide, and mixtures thereof; and wherein said polyol comprises at least one polyester polyol and at least one polyether polyol.
6. A method of making a moisture-reactive hot-melt composition comprising admixing components comprising at least one polyol, at least one polyisocyanate, and at least one acrylic polymer having tertiary-alkyl amide functionality, wherein said acrylic polymer having tertiary alkyl amide functionality has glass transition temperature of 20° C. to 120° C., and wherein said acrylic polymer having tertiary alkyl amide functionality has no hydroxyl functionality.
7. The method of claim 6 , wherein said acrylic polymer is 1 to 90 weight percent of said composition, based on the total weight of said composition; wherein said acrylic polymer includes at least one tertiary-alkyl amide functional monomer selected from the group consisting of N-tert-butylacrylamide, N-tert-butylmethacrylamide, 2-acrylamido 2-methylpropane sulfonic acid, diacetone acrylamide, diacetone methacrylamide, N-tert-octyl acrylamide, N-tert-octyl methacrylamide, and mixtures thereof; and wherein said polyol comprises at least one polyester polyol and at least one polyether polyol.
8. A method for bonding substrates comprising
(a) making a moisture-reactive hot-melt composition comprising admixing components comprising at least one polyol, at least one polyisocyanate, and at least one acrylic polymer having tertiary-alkyl amide functionality, wherein said acrylic polymer having tertiary alkyl amide functionality has glass transition temperature of 20° C. to 120° C., and wherein said acrylic polymer having tertiary alkyl amide functionality has no hydroxyl functionality;
(b) heating said hot-melt composition;
(c) applying said heated hot-melt composition to a first substrate;
(d) contacting said applied heated hot-melt composition with a second substrate; and
(e) cooling, or allowing to cool, said hot-melt composition.
9. The method of claim 8 , wherein said acrylic polymer is 1 to 90 weight percent of said composition, based on the total weight of said composition; wherein said acrylic polymer includes at least one tertiary-alkyl amide functional monomer selected from the group consisting of N-tert-butylacrylamide, N-tert-butylmethacrylamide, 2-acrylamido 2-methylpropane sulfonic acid, diacetone acrylamide, diacetone methacrylamide, N-tert-octyl acrylamide, N-tert-octyl methacrylamide, and mixtures thereof; and wherein said polyol comprises at least one polyester polyol and at least one polyether polyol.
10. The moisture-reactive hot-melt polymer composition of claim 1 , wherein said acrylic polymer having tertiary alkyl amide functionality has glass transition temperature of 30° C. to 120° C.
11. The method of claim 8 , wherein said acrylic polymer having tertiary alkyl amide functionality has glass transition temperature of 30° C. to 120° C.