UV curable epoxy/acrylate adhesive composition

Patent metadata

Field	Value
Publication number	US-11370944-B2
Application number	US-202016871543-A
Country	US
Kind code	B2
Filing date	May 11, 2020
Priority date	Jun 4, 2015
Publication date	Jun 28, 2022
Grant date	Jun 28, 2022

Abstract

An adhesive composition is described comprising a tetrahydrofurfuryl (meth)acrylate copolymer; an epoxy resin; a polyether polyol; and a hydroxy-functional film-forming polymer. The adhesive may be used in structural and semi-structural bonding applications.

First claim

What is claimed is:

1. A curable composition comprising
a. a tetrahydrofurfuryl (meth)acrylate copolymer;
b. an epoxy resin component;
c. a polyether polyol;
d. a hydroxy-functional film-forming polymer chosen from phenoxy resins, polycaprolactone polyols, polyester polyols, and polyvinyl acetal resins; and
e. a cationic photoinitiator.

2. The curable composition of claim 1 wherein the tetrahydrofurfuryl (meth)acrylate copolymer comprises
a) a tetrahydrofurfuryl (meth)acrylate monomer;
b) a C1-C8 alkyl (meth)acrylate ester monomer;
c) a cationically reactive functional (meth)acrylate ester monomer.

3. The curable composition of claim 1 wherein the weight ratio of epoxy resin to acrylate polymer is from 1.1:1 to 5:1.

4. The curable composition of claim 1 wherein the epoxy resin comprises cationically reactive (meth)acrylate ester functional monomer.

5. The curable composition of claim 1 wherein the cationic photoinitiator is a sulfonium or iodonium salt.

6. The curable composition of claim 1 wherein the epoxy resin component comprises two or more epoxy resins, wherein at least one epoxy resin has an epoxy equivalent weight of from about 300 to about 500, and at least one epoxy resin has an epoxy equivalent weight of from about 1000 to about 1200.

7. The curable composition of claim 1 wherein the tetrahydrofurfuryl (meth)acrylate copolymer has no acid functional monomer units.

8. The curable composition of claim 2 wherein the molar average carbon number of the C1-C8 alkyl (meth)acrylate ester is 3-6.

9. The curable composition of claim 1 wherein the tetrahydrofurfuryl (meth)acrylate copolymer is a tetrahydrofurfuryl/butyl acrylate copolymer.

10. The curable composition of claim 1 comprising:
a. 15 to 50 parts of a tetrahydrofurfuryl (meth)acrylate copolymer;
b. 25 to 50 parts of an epoxy resin component;
c. 5-15 parts of a polyether polyol;
d. a hydroxy-functional film-forming polymer;
wherein the sum of a) to d) is 100 parts by weight; and
e. a cationic photoinitiator.

11. The curable composition of claim 1 wherein the hydroxyl-functional film-forming polymer has a hydroxyl number of at least 0.01.

12. The curable composition of claim 1 further comprising a sensitizer.

13. The curable composition of claim 12 wherein the sensitizer is selected from ketones, coumarin dyes, xanthene dyes, acridine dyes, thiazole dyes, thiazine dyes, oxazine dyes, azine dyes, aminoketone dyes, porphyrins, aromatic polycyclic hydrocarbons, p-substituted aminostyryl ketone compounds, aminotriaryl methanes, merocyanines, squarylium dyes and pyridinium dyes.

14. A method of preparing the curable composition of claim 1 comprising the step of:
a) at least partially polymerizing a monomer mixture of (monomers) to produce a tetrahydrofurfuryl (meth)acrylate copolymer;
b) combining the copolymer with an epoxy resin, polyether polyol, the hydroxy-functional film-forming polymer a cationic photoinitiator and optionally additional free-radical photoinitiator;
c) optionally coating the mixture;
d) photopolymerizing the mixture.

15. The method of claim 14 wherein the monomer mixture of step a) is partially polymerized to a syrup copolymer composition comprising a solute tetrahydrofurfuryl (meth)acrylate copolymer in solvent monomer.

16. The method of claim 14 where the monomer mixture of step a) is fully polymerized to a THFA copolymer.

17. An adhesive article comprising a substrate and a layer of the curable composition of claim 1 on a surface thereof.

18. The adhesive article of claim 17 , wherein the composition has been partially cured.

19. A method of bonding comprising the steps of providing a substrate having a layer of the curable composition of claim 1 on a surface thereof, exposing the curable adhesive layer to actinic radiation to initiate curing, affixing the first substrate to a second substrate, and optionally heating the bonded substrates.

Assignees

• 3M Innovative Properties Co

Inventors

• Shafer Kathleen S
• Chastek Thomas Q
• Anderson Cyrus A

Classifications

• C08L71/12

  Polyphenylene oxides · CPC title

• C08L2205/025

  containing two or more polymers of the same hierarchy C08L, and differing only in parameters such as density, comonomer content, molecular weight, structure · CPC title

• C09J137/00

  Adhesives based on homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by a heterocyclic ring containing oxygen (based on polymers of cyclic esters of polyfunctional acids C09J131/00; based on polymers of cyclic anhydrides of unsaturated acids C09J135/00); Adhesives based on derivatives of such polymers · CPC title

• C09J163/00

  Adhesives based on epoxy resins; Adhesives based on derivatives of epoxy resins · CPC title

• C08L2205/035

  containing four or more polymers in a blend · CPC title