Multilayer imageable element

1. An imageable element comprising:

a substrate;

an underlayer over the substrate; and

a top layer over the underlayer;

in which:

the element comprises a photothermal conversion material;

the top layer is substantially free of the photothermal conversion material;

the top layer is ink receptive;

before thermal imaging, the top layer is not removable by an alkaline developer;

after thermal imaging to form imaged regions in the top layer, the imaged regions are removable by the alkaline developer;

the underlayer is removable by the alkaline developer, and

the top layer comprises a co-polymer that comprises K units, L units, and M units; in which:

the K units are selected from the group consisting of —[CH 2 C(R 1 )R 2 ]—, —[CH 2 CR 3 (CO 2 R 4 )]—, —[CH 2 CR 5 (CON(R 6 )(R 7 ))]—, —[C(R 8 )(COECO)C(R 9 )]—, and mixtures thereof;

the L units are selected from the group consisting of —[CH 2 CH(CN)]—, —[CH 2 C(CH 3 )(CN)]—, and mixtures thereof;

the M units are selected from the group consisting of —[CH 2 C(R 10 )(WSi(OR 11 ) 3 )]—, —[CH 2 C(R 12 )(CO 2 (B) n1 T)]—, —[(CH 2 C(R 13 )(CO 2 (CH 2 ) n2 N + (R 14 ) 3 )X − )]−, and mixtures thereof

R 1 , R 3 , R 5 , R 8 , R 9 , R 10 , R 12 , and R 13 are each independently hydrogen, methyl, or a mixture thereof;

R 2 is hydrogen, methyl, phenyl, substituted phenyl, halogen, alkoxy of one to four carbon atoms, acyl of one to five carbon atoms, acyloxy of one to five carbon atoms, vinyl, allyl, or a mixture thereof;

R 4 , R 6 , and R 7 are each independently hydrogen, alkyl of one to six carbon atoms, phenyl, or a mixture thereof;

each R 11 is independently phenyl, alkyl of one to eight carbon atoms, or a mixture thereof;

each R 14 is independently hydrogen, alkyl of one to six carbon atoms, or a mixture thereof;

E is oxygen or NR 15 in which R 15 is hydrogen, hydroxyl, phenyl, substituted phenyl, alkyl of one to six carbon atoms, benzyl, or a mixture thereof;

W is a bivalent linking group, a combination of bivalent linking groups, or a mixture of bivalent linking groups;

B is selected from the group consisting of —[CH 2 CH(R 16 )O]—, —[CH 2 C(R 17 )(OH)]—, and mixtures thereof, in which each R 16 and R 17 is independently hydrogen, alkyl of one to six carbon atoms, or a mixture thereof;

T is hydrogen, alkyl of one to eight carbon atoms, phenyl, or a mixture thereof;

X − is an anion;

n 1 is 1 to 100; and

n 2 is 2 to 8.

2. The element of claim 1 in which the M units are —[CH 2 C(R 10 )(WSi(OR 11 ) 3 )]—.

3. The element of claim 1 in which the M units are —[CH 2 C(R 12 )(CO 2 B n T)]—.

4. The element of claim 1 in which the M units are —[(CH 2 C(R 13 )(CO 2 (CH 2 ) n2 N + (R 14 ) 3 )X − )]—.

5. The element of claim 1 in which the top layer additionally comprises a phenolic resin selected from the group consisting of novolac resins, resole resins, and polyvinyl phenols.

6. The element of claim 1 in which:

the K units are selected from the group consisting of —[CH 2 C(R 1 )R 2 ]—, —[CH 2 CR 3 (CO 2 R 4 )]—, —[CH 2 CR 5 (CON(R 6 )(R 7 ))]—, and mixtures thereof;

R 2 is phenyl;

R 6 and R 7 are each independently hydrogen, methyl, or a mixture thereof;

R 4 and R 11 are each methyl;

W is a carbon-silicon single bond, a phenylene group, an alkylene group containing 2 to 6 carbon atoms, a carboxy group, a combination thereof, or a mixture thereof;

B is —[CH 2 CH 2 O]—; and

n 1 is 10 to 50.

7. The element of claim 6 in which the co-polymer consists essentially of about 1 wt % to about 78 wt % the K units, about 20 wt % to about 98 wt % the L units, and about 1 wt % to about 30 wt % the M units.

8. The element of claim 7 in which the M units are —[CH 2 C(R 10 )(WSi(OR 11 ) 3 )]—.

9. The element of claim 7 in which the M units are —[CH 2 C(R 12 )(CO 2 B n T)]—.

10. The element of claim 7 in which the M units are —[(CH 2 C(R 13 )(CO 2 (CH 2 ) n2 N + (R 14 ) 3 )X − )]—.

11. A method for forming an image, the method comprising the steps of:

a) thermally imaging an imageable element comprising: a substrate; an underlayer over the substrate; and a top layer over the underlayer; and forming an imaged imageable element comprising imaged and complementary unimaged regions in top layer;

in which:

the element comprises a photothermal conversion material;

the top layer is substantially free of the photothermal conversion material;

the top layer is ink receptive;

before thermal imaging, the top layer is not removable by an alkaline developer;

after thermal imaging to form imaged regions in the top layer, the imaged regions are removable by the alkaline developer;

the underlayer is removable by the alkaline developer, and

the top layer comprises a co-polymer that comprises K units, L units, and M units;

the K units are selected from the group consisting of —[CH 2 C(R 1 )R 2 ]—, —[CH 2 CR 3 (CO 2 R 4 )]—, —[CH 2 CR 5 (CON(R 6 )(R 7 ))]—, —[C(R 8 )(COECO)C(R 9 )]—, and mixtures thereof;

the L units are selected from the group consisting of —[CH 2 CH(CN)]—, —[CH 2 C(CH 3 )(CN)]—, and mixtures thereof;

the M units are selected from the group consisting of —[CH 2 C(R 10 )(WSi(OR 11 ) 3 )]—, —[CH 2 C(R 12 )(CO 2 (B) n1 T)]—, —[(CH 2 C(R 13 )(CO 2 (CH 2 ) n2 N + (R 14 ) 3 )X − )]—, and mixtures thereof

R 1 , R 3 , R 5 , R 8 , R 9 , R 10 , R 12 , and R 13 are each independently hydrogen, methyl, or a mixture thereof;

R 2 is hydrogen, methyl, phenyl, substituted phenyl, halogen, alkoxy of one to four carbon atoms, acyl of one to five carbon atoms, acyloxy of one to five carbon atoms, vinyl, allyl, or a mixture thereof;

R 4 , R 6 , and R 7 are each independently hydrogen, alkyl of one to six carbon atoms, phenyl, or a mixture thereof;

each R 11 is independently phenyl, alkyl of one to eight carbon atoms, or a mixture thereof;

each R 14 is independently hydrogen, alkyl of one to six carbon atoms, or a mixture thereof;

E is oxygen or NR 15 in which R 15 is hydrogen, hydroxyl, phenyl, substituted phenyl, alkyl of one to six carbon atoms, benzyl, or a mixture thereof;

W is a bivalent linking group, a combination of bivalent linking groups, or a mixture of bivalent linking groups;

B is selected from the group consisting of —[CH 2 CH(R 16 )O]—, —[CH 2 C(R 17 )(OH)]—, and mixtures thereof, in which each R 16 and R 17 is independently hydrogen, alkyl of one to six carbon atoms, or a mixture thereof;

T is hydrogen, alkyl of one to eight carbon atoms, phenyl, or a mixture thereof;

X − is an anion;

n 1 is 1 to 100; and

n 2 is 2 to 8; and

b) developing the imaged imageable element with the alkaline developer and removing the imaged regions.

12. The method of claim 11 in which the M units are —[CH 2 C(R 10 )(WSi(OR 11 ) 3 )]—.

13. The method of claim 11 in which the M units are —[CH 2 C(R 12 )(CO 2 B n T)]—.

14. The method of claim 11 in which the M units are —[(CH 2 C(R 13 )(CO 2 (CH 2 ) n2 N + (R 14 ) 3 )X − )]—.

15. The method of claim 11 in which the top layer additionally comprises a phenolic resin selected from the group consisting of novolac resins, resole resins, and polyvinyl phenols.

16. The method of claim 11 in which:

the K units are selected from the group consisting of —[CH 2 C(R 1 )R 2 ]—, —[CH 2 CR 3 (CO 2 R 4 )]—, —[CH 2 CR 5 (CON(R 6 )(R 7 ))]—, and mixtures thereof;

R 2 is phenyl;

R 6 and R 7 are each independently hydrogen, methyl, or a mixture thereof;

R 4 and R 11 are each methyl;

W is a carbon-silicon single bond, a phenylene group, an alkylene group containing 2 to 6 carbon atoms, a carboxy group, a combination thereof, or a mixture thereof;

B is —[CH 2 CH 2 O]—; and

n 1 is 10 to 50.

17. The method of claim 16 in which the co-polymer consists essentially of about 1 wt % to about 78 wt % the K units, about 20 wt % to about 98 wt % the L units, and about 1 wt % to about 30 wt % the M units.

18. The method of claim 17 in which the M units are —[CH 2 C(R 10 )(WSi(OR 11 ) 3 )]—.

19. The method of claim 17 in which the M units are —[CH 2 C(R 12 )(CO 2 B n T)]—.

20. The method of claim 17 in which the M units are —[(CH 2 C(R 13 )(CO 2 (CH 2 ) n2 N + (R 14 ) 3 )X − )]—.