Thermally switchable imageable elements containing betaine-containing co-polymers

1. An imageable element comprising an imageable layer over a support, in which the imageable layer consists essentially of a photothermal conversion material and a polymeric binder that comprises a polymer backbone with betaine-containing side chains, in which the betaines are selected from the group consisting of sulfobetaines, carboxybetaines, and mixtures thereof.

2. The element of claim 1 in which the polymeric binder comprises a polymer backbone with sulfobetaine-containing side chains.

3. The element of claim 1 in which the polymeric binder comprises a polymer backbone with carboxybetaine-containing side chains.

4. The element of claim 1 in which the polymeric binder comprises K units and L units in which:

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

the L units are selected from —[CH 2 C(R 8 )(Q(CH 2 ) m N(CH 3 ) 2 (CH 2 ) n SO 3 )]—, —[CH 2 C(R 9 )(Q(CH 2 ) m N(CH 3 ) 2 (CH 2 ) n CO 2 )]—, and mixtures thereof;

in which:

each R 1 , R 3 , R 7 , R 8 , and R 9 , is independently hydrogen, methyl, or a mixture thereof;

R 2 is hydrogen, methyl, phenyl, substituted phenyl, halogen, cyano, 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 5 , and R 6 are each independently hydrogen, alkyl of one to six carbon atoms, cycloalkyl of one to six carbon atoms, phenyl, or a mixture thereof;

E is oxygen or NR 10 in which R 10 is hydrogen, hydroxyl, phenyl, substituted phenyl, alkyl of one to six carbon atoms, benzyl, or a mixture thereof;

Q is CO 2 , O, CONH, CH 2 , or a mixture thereof;

m is 1 to 8;

n is 2 to 4; and

the ratio of K units to L units is about 99:1 to about 1:99.

5. The element of claim 4 in which:

the K units are selected from —[CH 2 C(R 1 )R 2 ]—, —[CH 2 CR 3 (CO 2 R 4 )]— and mixtures thereof;

R 2 is phenyl, cyano, or a mixture thereof;

R 4 is methyl;

Q is CO 2 , CONH, or a mixture thereof;

m is 1 to 4; and

the ratio of K units to L units is about 95:5 to about 20:80.

6. The element of claim 5 in which the L units are —[CH 2 —C(R 8 )(Q(CH 2 ) m N(CH 3 ) 2 (CH 2 ) n SO 3 )]—.

7. The element of claim 5 in which the L units are —[CH 2 —C(R 9 )(Q(CH 2 ) m N(CH 3 ) 2 (CH 2 ) n CO 2 )]—.

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

a) thermally imaging an imageable element and forming an imaged imageable element that comprises imaged and unimaged regions in an imageable layer,

in which:

the imageable element comprises the imageable layer over a support;

the imageable layer comprises a photothermal conversion material and a polymeric binder;

the binder comprises a polymer backbone with betaine-containing side chains, in which the betaines are selected from the group consisting of sulfobetaines, carboxybetaines, and mixtures thereof; and

b) without a development step, treating the imaged with ink, fountain solution, or a mixture of ink and fountain solution whereby the imaged regions take up ink and the unimaged regions remain essentially free of ink.

9. The method of claim 8 in which the polymeric binder comprises a polymer backbone with sulfobetaine-containing side chains.

10. The method of claim 8 in which the polymeric binder comprises a polymer backbone with carboxybetaine-containing side chains.

11. The method of claim 8 in which the imageable layer consists essentially of the photothermal conversion material and the polymeric binder.

12. The method of claim 8 in which the polymeric binder comprises K units and L units in which:

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

the L units are selected from —[CH 2 C(R 8 )(Q(CH 2 ) m N(CH 3 ) 2 (CH 2 ) n SO 3 )]—, —[CH 2 C(R 9 )(Q(CH 2 ) m N(CH 3 ) 2 (CH 2 ) n CO 2 )]—, and mixtures thereof;

in which:

each R 1 , R 3 , R 7 , R 8 , and R 9 , is independently hydrogen, methyl, or a mixture thereof;

R 2 is hydrogen, methyl, phenyl, substituted phenyl, halogen, cyano, 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 5 , and R 6 are each independently hydrogen, alkyl of one to six carbon atoms, cycloalkyl of one to six carbon atoms, phenyl, or a mixture thereof;

E is oxygen or NR 10 in which R 10 is hydrogen, hydroxyl, phenyl, substituted phenyl, alkyl of one to six carbon atoms, benzyl, or a mixture thereof;

Q is CO 2 , O, CONH, CH 2 , or a mixture thereof;

m is 1 to 8;

n is 2 to 4; and

the ratio of K units to L units is about 99:1 to about 1:99.

13. The method of claim 12 in which:

the K units are selected from —[CH 2 C(R 1 )R 2 ]—, —[CH 2 CR 3 (CO 2 R 4 )]— and mixtures thereof;

R 2 is phenyl, cyano, or a mixture thereof;

R 4 is methyl;

Q is CO 2 , CONH, or a mixture thereof;

m is 1 to 4; and

the ratio of K units to L units is about 95:5 to about 20:80.

14. The method of claim 13 in which the L units are —[CH 2 —C(R 8 )(Q(CH 2 ) m N(CH 3 ) 2 (CH 2 ) n SO 3 )]—.

15. The method of claim 13 in which the L units are —[CH 2 —C(R 9 )(Q(CH 2 ) m N(CH 3 ) 2 (CH 2 ) n CO 2 )]—.

16. The method of claim 13 in which the imageable layer consists essentially of the photothermal conversion material and the polymeric binder.

17. The method of claim 13 in which the polymeric binder consists essentially of the K units and the L units.

18. The method of claim 13 additionally comprising the step of transferring the ink to a receiving material.

19. The method of claim 8 additionally comprising the step of transferring the ink to a receiving material.