Mixed aryl/alkyl diester compositions
View Patent ↗Novel ester compositions are prepared by reacting 1) at least one diol, glycol or oligomeric glycol with 2) a mixture of at least one aromatic monocarboxylic acid and at least one aliphatic monocarboxylic acid containing from 2 to 4 carbon atoms. The compositions are effective plasticizers for a variety of polymers, particularly those employed in water-borne adhesives. The freezing point of the present ester mixtures and their efficacy as plasticizers and other types of additives and/or modifiers for a variety of polymer compositions can be varied by adjusting the relative concentrations of the aromatic and aliphatic acids used to prepare the ester composition.
1. An aqueous adhesive composition comprising:
A) a polymer selected from the group consisting of polyvinyl acetate, copolymers of vinyl acetate with at least one member selected from the group consisting of ethylene, esters of acrylic and methacrylic acids, and polyurethanes;
B) from 1 to 50 weight percent, based on the weight of said polymer, of a plasticizer composition comprising
1) a mixed diester corresponding to formula (I)
R 1 C(O)OR 2 O(O)CR 3 ;
2) from 20 to 100 weight percent, based on the weight of said mixed diester, of a diester corresponding to formula (II)
R 1 C(O)OR 2 O(O)CR 1 ;
3) from 0 to 40 weight percent, based on the weight of said mixed diester, of an ester corresponding to formula (III)
R 3 C(O)OR 2 O(O)CR 3 ; and
a total of from 0 to 30 weight percent, based on the total weight of said ester composition, of at least one monoester corresponding to at least one formula selected from the group consisting of R 1 C(O)OR 2 O(O)H and R 3 C(O)OR 2 O(O)H; and
an aqueous solvent;
wherein R 1 is at least one radical selected from the group consisting of phenyl, alkyl-substituted phenyl, and mixtures thereof, R 2 is at least one divalent radical of a formula selected from the group consisting of R 4 , —R 5 (OR 5 ) m — and mixtures thereof, R 3 is at least one member selected from the group consisting of hydrogen and alkyl radicals containing from 1 to 2 carbon atoms, R 4 is selected from the group consisting of linear and branched alkyl radical containing from 3 to 12 carbon atoms, R 5 is an alkylene radical containing from 2 to 6 carbon atoms, m represents at least one of the integers 1 and 2 and the molar ratio of R 1 to R 3 radicals is from 1:12 to 12:1.
2. An aqueous adhesive composition according to claim 1 wherein the molar ratio of R 1 to R 3 radicals is at least 1:1, and said composition is a liquid at 25° C., and said plasticizer composition constitutes from 3 to 25 weight percent of said adhesive composition.
3. An aqueous adhesive composition according to claim 1 wherein said composition additionally contains at least one of said monoesters.
4. An aqueous adhesive composition according to claim 1 wherein R 1 is phenyl, m is 1 or 2 and R 3 is methyl.
5. An aqueous adhesive composition according to claim 4 wherein R 4 is propyl and R 3 is methyl.
6. An aqueous composition according to claim 5 wherein R 2 is the divalent radical —R 5 (OR 5 ) m — and wherein in 88 percent of the radicals m is 1; in 10 percent of the radicals m is 2, and in 2 percent of the radicals m is 3.
7. An aqueous adhesive composition according to claim 6 wherein R 5 is ethylene.
8. A method for adhering two surfaces by applying a layer of the adhesive composition of claim 1 to at least one of said surfaces and then maintaining said surfaces in contact with one another for a period of time at least sufficient to form a cohesive bond between said surfaces.
9. A composite comprising at least two objects with adjacent mating surfaces that are cohesively bonded using the adhesive composition of claim 1 .