Two-component structure adhesive for the adhering of rare earth magnets
View Patent ↗Disclosed herein is a two-component structural adhesive based on organic compounds containing radically polymerizable multiple bonds, in particular substituted acrylates and/or methacrylates, which on account of their lack of acids are particularly suited for adhering rare earth permanent magnets based on neodymium-iron-boron.
1. A two-component structural adhesive composition, comprising:
(A) a first acid-free component comprising a monomer containing one or more radically polymerizable multiple bonds;
(B) a second acid-free component comprising a radical initiator or a radical activator;
wherein:
the first component further comprises a radical initiator and the second component comprises a radical activator, or the first component further comprises a radical activator and the second component comprises a radical initiator; and
the first component or the second component, or both, further comprise a resin or resin mixture comprising one or more phenoxy resins of the bisphenol A series, one or more phenoxy resins of the bisphenol F series, one or more solid epoxy resins of the bisphenol A series, one or more solid weight epoxy resins of the bisphenol F series, or mixtures thereof, and having an average molecular weight between 2000 and 100,000 g/mo.
2. The two-component adhesive composition according to claim 1 , wherein the resin or resin mixture has an average molecular weight between 3000 and 50,000 g/mol.
3. The two-component adhesive composition according to one of claim 2 , wherein the resin or resin mixture comprises a bisphenol A phenoxy resin having an average molecular weight of approximately 30,000 g/mol.
4. The two-component adhesive composition according to claim 1 , wherein the resin or resin mixture comprises a bisphenol A epoxy resin having an average molecular weight >3000 g/mol.
5. The two-component adhesive composition according to claim 1 , wherein the monomer containing one or more radically polymerizable multiple bonds comprises one or more of:
methacrylates of aliphatic alcohols having one or more hydroxy groups, methacrylates of aromatic alcohols having one or more hydroxyl groups.
6. The two-component adhesive composition according to claim 1 , wherein said first acid-free component, or said second acid-free component, or both, further comprise one or more additives selected from the group consisting of viscosity-increasing polymers, organosilanes, curing accelerators, mineral fillers, rheological additives, softeners, and solvents.
7. The two-component adhesive composition according to claim 1 , wherein said first acid-free component, or said second acid-free component, or both, further comprises a film-forming polymer.
8. The two-component adhesive composition according to claim 1 , wherein resin or resin mixture further comprises one or more polymers compatible with said one or more polymers of phenol-ether monomers, epoxy monomers, or combinations thereof.
9. The two-component adhesive composition according to claim 1 , wherein said resin or resin mixture is present in the adhesive in an amount between 10% by weight and 80% by weight of the adhesive.
10. The two-component adhesive composition according to claim 1 , wherein the radical initiator comprises an organic peroxide.
11. The two-component adhesive composition according to claim 1 , wherein the radical activator comprises an aromatic amine.
12. The two-component adhesive composition according to claim 10 , wherein the organic peroxide comprises dibenzoyl peroxide, cumene hydroperoxide, or a combination thereof.
13. The two-component adhesive composition according to claim 11 , wherein the aromatic amine is N,N-dimethyltoluidine, phenylbutylimine, 3,5-diethyl-1,2-dihydro-1-pheny1-2-propylpyridine, or a combination thereof.
14. The two-component adhesive composition according to claim 1 , wherein said first acid-free component, or said second acid-free component, or both, further comprise a coreagent.
15. The two-component adhesive composition according to claim 1 , wherein:
said first acid-free component comprises:
approximately 65% by weight of a mixture of methacrylate compounds,
approximately 32.5% by weight of a bisphenol A epoxy resin, and
approximately 2.5% by weight dimethyltoluidine; and
said second acid-free component comprises:
approximately 9% by weight polymethylmethacrylate, approximately 1% by weight dibenzoyl peroxide, and acetone.
16. The two-component adhesive composition according to claim 1 , wherein:
said first acid-free component comprises:
approximately 60% by weight of a mixture of methacrylate compounds,
approximately 36% by weight of a phenoxy resin having a molecular weight of approximately 22,000 g/mol, approximately 2% by weight cumene hydroperoxide, and approximately 2% by weight saccharine, and
said second acid-free component comprises:
approximately 1% by weight N,N-dimethyltoluidine, and cyclohexane.
17. An adhesive formed by curing the two-component adhesive composition according to claim 1 .
18. The two-component adhesive composition according to claim 5 , wherein the aliphatic alcohols comprise alkanols, glycol ethers, or polyols.
19. The two-component adhesive composition according to claim 18 , wherein the alkanols comprise methanol, ethanol, or propanol.
20. The two-component adhesive composition according to claim 18 , wherein the polyols comprise glycerin or diols.
21. The two-component adhesive composition according to claim 6 , wherein said viscosity-increasing polymer comprises polymethylmethacrylate, or said rheological additive is fumed silica, or a combination of these.
22. The two-component adhesive composition according to claim 8 , wherein said one or more compatible polymers are selected from the group consisting of polymethylmethacrylates, methacrylate copolymers, polysulfones, polyesters, and polyurethanes.
23. The two-component adhesive composition according to claim 9 , wherein the amount of resin is between 30% by weight and 60% by weight of the adhesive composition.
24. The two-component adhesive composition according to claim 14 , wherein said coreagent is in the said first acid-free component when said radical activator is present therein, and is in said second acid-free component when said radical activator is present therein.
25. The two-component adhesive composition according to claim 14 , wherein said coreagent comprises saccharine.