Addition-fragmentation agents

1. A non-aqueous polymerizable composition comprising at least one free-radically polymerizable monomer, an initiator and an addition-fragmentation agent of the formula:

wherein

R 1 , R 2 and R 3 are each independently Z m -Q-, a (hetero)alkyl group or a (hetero)aryl group with the proviso that at least two of R 1 , R 2 and R 3 is Z m -Q-,

Q is a linking group having a valence of m+1;

Z is an ethylenically unsaturated polymerizable group,

m is 1 to 6;

each X 1 is independently —O— or —NR 4 —, where R 4 is H or C 1 -C 4 alkyl, and

n is 0 or 1.

2. The polymerizable composition of claim 1 where Z comprises a vinyl, vinyloxy, (meth)acryloxy, (meth)acrylamido, styrenic and acetylenic functional groups.

3. The polymerizable composition of claim 1 where Z is selected from:

wherein R 4 is H or C 1 -C 4 alkyl.

4. The polymerizable composition of claim 1 wherein Q is selected from

from —O—, —S—, —NR 4 —, —SO 2 —, —PO 2 —, —CO—, —OCO—, —R 6 —, —NR 4 —CO—NR 4 —, —NR 4 —CO—O—, —NR 4 —CO—NR 4 —, —CO—O—R 6 —, —CO—NR 4 —R 6 —, —R 6 —CO—O—R 6 —, —O—R 6 —, —S—R 6 —, —NR 4 —R 6 —, —SO 2 —R 6 —, —PO 2 —R 6 —, —CO—R 6 —, —OCO—R 6 —, —NR 4 —CO—R 6 —, and NR 4 —R 6 —CO—O—, wherein each R 4 is hydrogen, a C 1 to C 4 alkyl group, or aryl group, each R 6 is an alkylene group having 1 to 6 carbon atoms, a 5- or 6-membered cycloalkylene group having 5 to 10 carbon atoms, or a divalent arylene group having 6 to 16 carbon atoms, with the proviso that Q-Z does not contain peroxidic linkages.

5. The polymerizable composition of claim 1 where Q is an alkylene.

6. The polymerizable composition of claim 5 wherein Q is an alkylene of the formula —C r H 2r —, where r is 1 to 10.

7. The polymerizable composition of claim 1 where Q is a hydroxyl-substituted alkylene.

8. The polymerizable composition of claim 1 where Q is —CH 2 —CH(OH)—CH 2 —.

9. The polymerizable composition of claim 1 where Q is an aryloxy-substituted alkylene.

10. The polymerizable composition of claim 1 where R 5 is an alkoxy-substituted alkylene.

11. The polymerizable composition of claim 1 wherein R 1 —X 1 — groups and R 3 —X 1 — groups are selected from H 2 C═C(CH 3 )C(O)—O—CH 2 —CH(OH)—CH 2 —O—, H 2 C═C(CH 3 )C(O)—O—CH 2 —CH(O—(O)C(CH 3 )═CH 2 )—CH 2 —O—, H 2 C═C(CH 3 )C(O)—O—CH(CH 2 OPh)-CH 2 —O—, H 2 C═C(CH 3 )C(O)—O—CH 2 CH 2 —N(H)—C(O)—O—CH(CH 2 OPh)-CH 2 —O—, H 2 C═C(CH 3 )C(O)—O—CH 2 —CH(O—(O)C—N(H)—CH 2 CH 2 —O—(O)C(CH 3 )C═CH 2 )—CH 2 —O—, H 2 C═C(H)C(O)—O—(CH 2 ) 4 —O—CH 2 —CH(OH)—CH 2 —O—, H 2 C═C(CH 3 )C(O)—O—CH 2 —CH(O—(O)C—N(H)—CH 2 CH 2 —O—(O)C(CH 3 )C═CH 2 )—CH 2 —O—, CH 3 —(CH 2 ) 7 —CH(O—(O)C—N(H)—CH 2 CH 2 —O—(O)C(CH 3 )C═CH 2 )—CH 2 —O—, H 2 C═C(H)C(O)—O—(CH 2 ) 4 —O—CH 2 —CH(—O—(O)C(H)═CH 2 )—CH 2 —O— and H 2 C═C(H)C(O)—O—CH 2 —CH(OH)—CH 2 —O—.

12. The polymerizable composition of claim 1 comprising:

a) 85 to 100 parts by weight of an (meth)acrylic acid ester of non-tertiary alcohol;

b) 0 to 15 parts by weight of an acid functional ethylenically unsaturated monomer;

c) 0 to 10 parts by weight of a non-acid functional, ethylenically unsaturated polar monomer;

d) 0 to 5 parts vinyl monomer; and

e) 0 to 5 parts of a multifunctional (meth)acrylate;

based on 100 parts by weight total monomer, and

f) 0.1 to 10 parts by weight of the addition-fragmentation agent, based on 100 parts by weight of a) to e).

13. The polymerizable composition of claim 12 further comprising 0.01 to 5 parts of a multifunctional (meth)acrylate.

14. The polymerizable composition of claim 1 further comprising an organic solvent.

15. The polymerizable composition of claim 1 having less than 0.1 wt. % water.

16. An article comprising a layer of the polymerizable composition of claim 1 on a substrate.

17. An article comprising the cured polymerizable composition of claim 1 on a substrate.

18. A method of bonding two substrates together comprising the steps of coating the polymerizable composition of claim 1 to a surface of one or both substrates, contacting the coated surfaces, optionally with pressure, and curing the polymerizable composition.

19. A method of bonding two substrates together comprising the steps of coating the polymerizable composition of claim 1 to a surface of one or both substrates, wherein the coating of polymerizable composition is at least partially cured, contacting the coated surfaces optionally with pressure, and further curing the polymerizable compositions if necessary.