Degradable crosslinkers for (meth)acrylic resins and methods thereof
Disclosed herein is a thioester-containing (meth)acrylate compound comprising at least two thioester moieties and at least 2 (meth)acrylate moieties and a method for making such compounds. These compounds can be used in (meth)acrylic resins as a crosslinking agent. Upon exposure to a nucleophilic solvent, cured (meth)acrylic resins derived from these thioester-containing (meth)acrylate compounds can be degraded.
1. A curable composition comprising:
a mono (meth)acrylate ester monomer comprising at least 4 and no more than 20 carbon atoms;
a thioester-containing (meth)acrylate crosslinking agent; and
an initiator system,
wherein the thioester-containing (meth)acrylic crosslinking agent is
(a) of formula (I)
wherein:
R 1 is (i) X 2 L 2 X 2 , wherein each X 2 is independently S or O; and L 2 is a divalent alkylenyl group, which may be linear or branched or
(ii) C(X 3 ) m L 3 C(X 4 ) p , wherein X 3 and X 4 are independently a linear or branched alkyl group, L 3 is divalent group comprising a S or O atom, m and p are independently selected from 0, 1 or 2, and n in formula (I) is an integer from 2 to 6, wherein p+m+n=6;
R 2 is a divalent alkylenyl group comprising at least 1 carbon atom and optionally comprising at least 1 ester linkage;
R 3 is a divalent alkylenyl group comprising at least 1 carbon atom and optionally comprising at least 1 ester linkage; and
R 4 is a H or a methyl group;
(b) is at least one of the following:
where R 4 is H or methyl group.
2. The curable composition of claim 1 , wherein the curable composition comprises at least 3 and at most 50% by weight of the thioester-containing (meth)acrylic crosslinking agent based on the total weight of monomers.
3. The curable composition of claim 1 , wherein the curable composition further comprises an acid-functional monomer.
4. The curable composition of claim 1 , wherein the curable composition further comprises a polar ethylenically unsaturated monomer, optionally wherein the curable composition comprises at least 0.1% and no more than 99% by weight of the polar ethylenically unsaturated monomer based on the total weight of monomers.
5. The curable composition of claim 1 , wherein the curable composition further comprises a second multifunctional ethylenically unsaturated monomer.
6. The curable composition of claim 1 , wherein the initiator is a photoinitiator or a redox initiator system.
7. A cured (meth)acrylate composition derived from the curable composition of claim 1 .
8. The cured (meth)acrylate composition of claim 7 , wherein the cured (meth)acrylate composition is an adhesive, a coating, or a sealant.
9. A method of degrading a cured (meth)acrylate composition, the method comprising:
contacting the cured (meth)acrylate composition according to claim 7 to a nucleophilic solvent.