Impregnation sealant for electronic components

1. An anaerobically curable impregnation sealant composition comprising:

(a) at least two (meth)acrylic monofunctional monomers containing a C 4 -C 20 alkyl hydrophobic moiety, wherein (a) comprises lauryl (meth)acrylate and trimethylcyclohexyl (meth)acrylate;

(b) at least one (meth)acrylic monofunctional monomer containing a hydroxyl group;

(c) at least one modified polyester urethane methacrylate resin having a weight average molecular weight of from about 8000 to about 18000 g/mol and a glass transition temperature of less than ˜20° C., present in an amount ranging from about 10 to 30 wt. % based on total weight of the composition, wherein the amount of (c) is selected such that viscosity of the composition is suitable for impregnation; and

(d) triallylisocyanurate, triallylcyanurate, or derivatives thereof, or a combination thereof, present in an amount of about 5 to 15 wt. % based on total weight of the composition.

2. The composition of claim 1 , wherein (a) the (meth)acrylic monofunctional monomers containing the hydrophobic moiety further comprises one or more monomers having C 6 -C 12 alkyl groups.

3. The composition of claim 1 , wherein (a) the (meth)acrylic monofunctional monomer containing the hydrophobic moiety further comprises monomer selected from the group consisting of 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl(meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and combinations thereof.

4. The composition of claim 1 , wherein (b) is a hydroxyalkyl(meth)acrylate having from C 1 to C 10 carbon atoms in the alkyl group.

5. The composition of claim 1 , wherein (b) is selected from the group consisting of hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate (HPMA), and combinations thereof.

6. The composition of claim 1 , wherein (c) wherein the polyester urethane methacrylate resin has a weight average molecular weight of from 12000 to 18000 g/mol.

7. The composition of claim 1 , wherein (d) is triallylisocyanurate or a derivative thereof.

8. The composition of claim 1 , wherein (d) is triallylcyanurate or a derivative thereof.

9. The composition of claim 1 , wherein (d) is included in the composition in an amount of about 10 wt. % based on the total weight of the composition.

10. The composition of claim 6 wherein (c) the modified polyester urethane methacrylate resin has a glass transition temperature less than −30° C.

11. The composition of claim 6 , wherein (c) the modified polyester urethane methacrylate resin has a glass transition temperature less than −40° C.

12. The composition of claim 1 , wherein (c) the modified polyester urethane methacrylate resin is a reaction product between polyester diol and toluene diisocyanate.

13. The composition of claim 1 , wherein a reaction weight ratio of equivalents of (meth)acrylate monomers containing a hydroxyl group to (meth)acrylate monomers containing a hydrophobic moiety is about 1:1 to about 1:6.

14. The composition of claim 1 , wherein a reaction weight ratio of equivalents of the modified polyester urethane (meth)acrylate resin to (meth)acrylic monomers containing a hydrophobic moiety and (meth)acrylic monofunctional monomers containing a hydroxyl group is about 1:0.5 to about 1:6.

15. The composition of claim 1 further comprising (f) at least one catalyst capable of initiating free-radical cure of the composition.

16. The composition of claim 1 further comprising (e) a polyfunctional monomer.

17. The composition of claim 1 , wherein (c) has a glass transition temperature less than −40° C.; (d) is included in the composition in an amount of about 10 wt. % based on the total weight of the composition and viscosity of the uncured sealant composition is less than 50 mPa·s.

18. An anaerobically curable impregnation sealant composition comprising:

(a) at least two (meth)acrylic monofunctional monomers containing a hydrophobic moiety, wherein (a) comprises lauryl (meth)acrylate and trimethylcyclohexyl (meth)acrylate;

(b) at least one (meth)acrylic monofunctional monomer containing a hydroxyl group, and is present in an amount from about 3 to about 45 wt. % based on total weight of the composition;

(c) at least one modified polyester urethane methacrylate resin having a weight average molecular weight of from about 8000 to about 18000 g/mol, a glass transition temperature of less than −40° C., and present in an amount ranging from about 10 to 30 wt. % based on total weight of the composition; and

(d) triallylisocyanurate, triallylcyanurate, or derivatives thereof, or a combination thereof; and

wherein (c) the at least one modified polyester urethane methacrylate resin comprises the reaction product of reactants:

(i) a polyester diol,

(ii) toluene diisocyanate, and

(iii) a polymerizable methacrylate acid ester;

wherein viscosity of uncured sealant composition is less than 100 mPa·s.

19. The composition of claim 18 , wherein said (i) polyester diol is poly(3-methyl-1,5-pentanediol adipate).

20. The composition of claim 18 , wherein said (i) polyester diol is a reaction product of neopentyl glycol and a diol adipate, the diol adipate containing at least 3 carbons.

21. The composition of claim 18 , wherein (a) the hydrophobic moiety includes monomers containing a C 4 -C 20 alkyl groups; and wherein equivalent weight of the polyester diol to the toluene diisocyanate is in a ratio of about 1.0 to 4.0 parts diol to about 1.0 to 4.0 parts diisocyanate.

22. The composition of claim 21 , wherein equivalent weight of the polyester diol to the toluene diisocyanate is in a ratio of about 1.0 parts diol to about 2.0 parts diisocyanate.

23. The composition of claim 18 , wherein

(a) the at least two (meth)acrylic monofunctional monomers containing a hydrophobic moiety are present in a total amount of about 20 to 60 wt. % based on the total weight of the sealant composition;

(b) the at least one (meth)acrylic monofunctional monomer containing a hydroxyl group is present in an amount of about 5 to about 33 wt. % based on total weight of the composition;

(c) the at least one modified polyester urethane methacrylate resin has a molecular weight of 12000 to about 18000 g/mol, and is present in an amount of about 10 to 30 wt. % based on total weight of the composition; and

(d) the triallylisocyanurate, triallylcyanurate, or derivatives thereof, or a combination thereof, is present in an amount of about 5 to 15 wt. % based on total weight of the composition.

24. A method of manufacturing an anaerobically curable composition comprising:

step a) providing (a) at least two (meth)acrylic monofunctional monomers containing a C 4 -C 20 alkyl hydrophobic moiety and (b) at least one (meth)acrylic monofunctional monomer containing a hydroxyl group, wherein (a) comprises lauryl (meth)acrylate and trimethylcyclohexyl (meth)acrylate; and

step b) combining said monomers with (c) at least one modified polyester urethane methacrylate resin having a weight average molecular weight of from about 8000 to about 18000 g/mol, and (d) triallylisocyanurate, triallylcyanurate, or derivatives thereof, or a combination thereof; wherein a reaction weight ratio of equivalents of the modified polyester urethane methacrylate resin to (meth)acrylic monomers containing a hydrophobic moiety and (meth)acrylic monofunctional monomers containing a hydroxyl group is about 1:0.5 to about 1:6.

25. The method of claim 24 , wherein (a) the (meth)acrylic monofunctional monomers containing the hydrophobic moiety further comprises one or more monomers having C 6 -C 12 alkyl groups, and combinations thereof.

26. The method of claim 24 , wherein (a) the methacrylic monofunctional monomer containing the hydrophobic moiety further comprises monomer selected from the group consisting of 2-ethylhexyl (meth)acrylate, isobornyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, and combinations thereof.

27. The method of claim 24 , wherein (b) is a hydroxyalkyl(meth)acrylates having from C 1 to C 10 carbon atoms in the alkyl group.

28. The method of claim 24 , wherein (b) is selected from the group consisting of hydroxyethyl methacrylate (HEMA), hydroxypropyl methacrylate (HPMA), and combinations thereof.

29. The method of claim 24 , wherein (c) the at least one modified polyester urethane methacrylate resin has a weight average molecular weight of from about 12000 to about 18000 g/mol and a glass transition temperature less than −40° C.

30. An article of manufacture impregnated with a heat curable composition according to claim 1 , said article comprising a porous metal surface and a plastic surface.

31. The article according to claim 30 , wherein said article is an electrical component.