Alkaline developer for radiation sensitive compositions

1. An alkaline developer for irradiated radiation sensitive compositions, which developer is based on water and at least one inorganic salt having an alkaline reaction, wherein the developer has a pH of at least 11 and comprises at least three structurally different surfactants of formulae (A), (B) and (C), wherein the surfactants (A) and (B) are both amphoteric and wherein the surfactant of formula (A) has one anionic group, the surfactant of formula (B) has two anionic groups, the surfactant of formula (C) is non-ionic and has at least one non-ionic hydrophilic group comprising a polyethylenoxide group having from 3 to 100 ethylenoxide units, and the concentration of each of the surfactants of formulae (A), (B) and (C) in the developer is at least 0.05 weight-% based on the total weight of the developer.

2. An alkaline developer according to claim 1 , wherein the anionic groups are selected from sulfonate and carboxylate groups.

3. An alkaline developer according to claim 1 , wherein the surfactant of formula (A) is of formula (I)

and wherein

R 1 represents a substituted or unsubstituted alkyl group having at least 6 carbon atoms,

R 2 represents H or has the same meaning as R 1 ,

X 1 represents a substituted or unsubstituted alkenyl group,

Z 1 represents —COO, —SO 3 , —OSO 3 , —PO 3 Y or —OPO 3 Y, and

Y represents a cation to compensate for the charge.

4. An alkaline developer according to claim 1 , wherein the surfactant of formula (B) is of formula (II)

and wherein

R 3 represents a substituted or unsubstituted alkyl group having at least 6 carbon atoms,

X 2 , X 3 independently represent a substituted or unsubstituted alkenyl group,

Z 2 , Z 3 independently represent —COO, —SO 3 , —OSO 3 , —PO 3 Y or —OPO 3 Y, and

Y represents a cation to compensate for the charge.

5. An alkaline developer according to claim 1 , wherein the surfactant of formula (C) is of formula (III)

R 4 —R 5   (III),

and wherein

R 4 represents a substituted or unsubstituted alkyl group having at least 6 carbon atoms,

R 5 represents —O—(—CH 2 —CH 2 —O—) x —H, and

x is an integer from 3 to 100.

6. A method of making a lithographic printing plate comprising the steps of imagewise exposing a lithographic printing plate precursor, and processing it in an alkaline developer according to claim 1 .

7. An alkaline developer according to claim 2 , wherein the surfactant of formula (A) is of formula (I)

and wherein

R 1 represents a substituted or unsubstituted alkyl group having at least 6 carbon atoms,

R 2 represents H or has the same meaning as R 1 ,

X 1 represents a substituted or unsubstituted alkenyl group,

Z 1 represents —COO, —SO 3 , —OSO 3 , —PO 3 Y or —OPO 3 Y, and

Y represents a cation to compensate for the charge.

8. An alkaline developer according to claim 2 , wherein the surfactant of formula (B) is of formula (II)

and wherein

R 3 represents a substituted or unsubstituted alkyl group having at least 6 carbon atoms,

X 2 , X 3 independently represent a substituted or unsubstituted alkenyl group,

Z 2 , Z 3 independently represent —COO, —SO 3 , —OSO 3 , —PO 3 Y or —OPO 3 Y, and

Y represents a cation to compensate for the charge.

9. An alkaline developer to claim 7 , wherein the surfhctant of formula (B) is of formula (II)

and wherein

R 3 represents a substituted or unsubstituted alkyl group having at least 6 carbon atoms,

X 2 , X 3 independently represent a substituted or unsubstituted alkenyl group,

Z 2 , Z 3 independently represent —COO, —SO 3 , —OSO 3 , —PO 3 Y or —OPO 3 Y, and

Y represents a cation to compensate for the charge.

10. An alkaline developer according to claim 3 , wherein the surfactant of formula (B) is of formula (II)

and wherein

R 3 represents a substituted or unsubsrftuted alkyl group having at least 6 carbon atoms,

X 2 , X 3 independently represent a substituted or unsubstituted alkenyl group,

Z 2 , Z 3 independently represent —COO, —SO 3 , —OSO 3 , —PO 3 Y or —OPO 3 Y, and

Y represents a cation to compensate for the charge.

11. An alkaline developer according to claim 2 , wherein the surfactant of formula (C) is of formula (III)

R 4 —R 5   (III),

and wherein

R 4 represents a substituted or unsubstituted alkyl group having at least 6 carbon atoms,

R 5 represents —O—(—CH 2 —CH 2 —O—) x —H, and

x is an integer from 3 to 100.

12. An alkaline developer according to claim 7 , wherein the surfactant of formula (C) is of formula (III)

R 4 —R 5   (III),

and wherein

R 4 represents a substituted or unsubstituted alkyl group having at least 6 carbon atoms,

R 5 represents —O—(—CH 2 —CH 2 —O—) x —H, and

x is an integer from 3 to 100.

13. An alkaline developer according to claim 3 , wherein the surfactant of formula (C) is of formula (III)

R 4 —R 5   (III),

and wherein

R 4 represents a substituted or unsubstituted alkyl group having at least 6 carbon atoms,

R 5 represents —O—(—CH 2 —CH 2 —O—) x —H, and

x is an integer from 3 to 100.

14. An alkaline developer according to claim 4 , wherein the surfactant of formula (C) is of formula (III)

R 4 —R 5   (III),

and wherein

R 4 represents a substituted or unsubstituted alkyl group having at least 6 carbon atoms,

R 5 represents —O—(—CH 2 —CH 2 —O—) x —H, and

x is an integer from 3 to 100.

15. An alkaline developer according to claim 11 , wherein the surfactant of formula (B) is of formula (II)

and wherein

R 3 represents a substituted or unsubstituted alkyl group having at least 6 carbon atoms,

X 2 , X 3 independently represent a substituted or unsubstituted alkenyl group,

Z 2 , Z 3 independently represent —COO, —SO 3 , —OSO 3 , —PO 3 Y or —OPO 3 Y, and

Y represents a cation to compensate the charge.

16. An alkaline developer according to claim 12 , wherein the surfacrant of formula (B) is of formula (II)

and wherein

R 3 represents a substituted or unsubstituted alkyl group having at least 6 carbon atoms,

X 2 , X 3 independently represent a substituted or unsubstituted alkenyl group,

Z 2 , Z 3 independently represent —COO, —SO 3 , —OSO 3 , —PO 3 Y or —OPO 3 Y, and

Y represents a cation to compensate the charge.

17. An alkaline developer according to claim 14 , wherein the surfactant of formula (A) is of formula (I)

and wherein

R 2 represents a substituted or unsubstituted alkyl group having at least 6 carbon atoms,

R 2 represents H or has the same meaning as R 1 ,

X 1 represents a substituted or unsubstituted alkenyl group,

Z 1 represents —COO, —SO 3 , —OSO 3 , —PO 3 Y or —OPO 3 Y, and

Y represents a cation to compensate for the charge.

18. A method of making a lithographic printing plate comprising the steps of imagewise exposing a lithographic printing plate precursor, and processing it in an alkaline developer according to claim 17 .