THERMALLY STABLE POLYESTER (ALKYD) POLYMERS
A polyester (alkyd) for use in hot melt adhesive composition is provided. Unreacted carboxyl groups in the alkyd resin are reacted with a monofunctional epoxide to form functional groups that are unreactive with alcohols.
1 . A polyester (alkyd) for use in hot melt adhesives wherein unreacted carboxyl groups in the alkyd have been reacted with at least one monofunctional epoxide to form one or more functional groups that are unreactive with alcohols.
2 . The polyester (alkyd) of claim 1 , wherein the alkyd has an acid value of 3.0 or less.
3 . The polyester (alkyd) of claim 1 , wherein the hot melt adhesive has a viscosity increase of less than 25% after 72 hours at 130° C.
4 . The polyester (alkyd) of claim 1 , wherein the at least one monofunctional epoxide comprises glycidyl neodecanoate,
5 . A process for heat stabilizing a hot melt adhesive that comprises a polyester (alkyd), wherein the process comprises reacting unreacted carboxyl groups in the alkyd with at least one monofunctional epoxide.
6 . The process of claim 5 , wherein after the unreacted carboxyl groups have reacted with the at least one monofunctional epoxide, the acid value of the polyester (alkyd) is 3.0 or less.
7 . The process of claim 5 , wherein after the unreacted carboxyl groups have reacted with the at least one monofunctional epoxide, the polyester (alkyd) is thermally stable such that the viscosity increase of the alkyd after 72 hours at 130° C. is less than 25%.
8 . The process of claim 5 , wherein the at least one monofunctional epoxide comprises glycidyl neodecanoate.
9 . A hot melt adhesive composition comprising 10 to 40 percent by weight of a polymer or copolymer to provide cohesive strength, 50 to 80 percent by weight of a polyester (alkyd) wherein unreacted carboxyl groups in the alkyd have been reacted with at least one monofunctional epoxide to form one or more functional groups that are unreactive with alcohols.
10 . The hot melt adhesive composition of claim 9 , wherein the alkyd has an acid value of 3.0 or less.
11 . The hot melt adhesive composition of claim 9 , wherein the hot melt adhesive has a viscosity increase of less than 25% after 72 hours at 130° C.
12 . The hot melt adhesive composition of claim 9 , wherein the at least one monofunctional epoxide comprises glycidyl neodecanoate.
13 . The hot melt adhesive composition of claim 9 wherein the polymer or copolymer to provide cohesive strength is selected from the group consisting of ethylene-vinyl acetate, ethylene acrylate copolymers, styrene-butadiene, ethylene-ethyl acrylate, low density polypropylene, polyamides, other polyesters, polyurethanes, polyvinyl alcohols, polylactic acid, and blends thereof.