Photosensitive composition containing photosensitive polyamide and thiazoline photoinitiator and negative working photosensitive element
AssigneeKodak Polychrome Graphics LLC
InventorThap DoMinh
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Abstract
A photosensitive composition can be used to prepare negative-working photosensitive elements such as lithographic printing plates. The composition includes a first photocrosslinkable aromatic resin having photocrosslinkable groups and a number average molecular weight of at least about 1500. Also included is a polymerizable monomer, a photocrosslinkable polyester, a photoinitiator, and an aromatic thiazoline photosensitizer. The photosensitive resins are present at a total weight ratio to the monomer of at least 1.5:1.
Claims25
A photosensitive composition comprising:
- a) a resin containing ethylenically unsaturated photocrosslinkable groups,
- b) an ethylenically unsaturated photopolymerizable monomer,
- c) a photocrosslinkable polyester resin,
- d) a halogenated triazine photoinitiator, and
- e) an aromatic thiazoline photosensitizer,
- the weight ratio of the total of said resin a) and resin c) to said monomer b) being at least 1.5:1,
- said resin a) having any of structures I, II or III:
- ##STR14## wherein X is --NH-- or --O--, R.sub.1 is a divalent aromatic, cycloaliphatic or aliphatic group having at least 2 carbon atoms,
- R.sub.2 and R.sub.3 are independently hydrogen or an organic radical containing a photopolymerizable olefinic double bond, provided at least one of R.sub.2 and R.sub.3 is said organic radical,
- R.sub.4 and R.sub.5 are independently, a hydrocarbon having 1 to 8 carbon atoms, perfluoro, or a perhalofluoro aliphatic group having 1 to 8 carbon atoms, or together, R.sub.4 and R.sub.5 form an oxo group,
- m is 0 or 1, and
- n is a positive integer corresponding to the number of units in the polymer and is sufficiently large to provide said resin a) with a number average molecular weight of at least about 1500.
The composition of claim 12 wherein said photosensitizer is N-methyl-2-benzoylmethylene-.beta.-naphthothiazoline.
A photosensitive element comprising a support and having thereon a photosensitive image-forming layer, said photosensitive image-forming layer comprising:
- a) a resin containing ethylenically unsaturated photocrosslinkable groups,
- b) an ethylenically unsaturated photopolymerizable monomer,
- c) a photocrosslinkable polyester resin,
- d) a photoinitiator, and
- e) an aromatic thiazoline photosensitizer,
- the weight ratio of the total of said resin a) and resin c) to said monomer b) being at least 1.5:1,
- said resin a) having any of structures I, II or III:
- ##STR16## wherein X is --NH-- or --O--, R.sub.1 is a divalent aromatic, cycloaliphatic or aliphatic group having at least 2 carbon atoms,
- R.sub.2 and R.sub.3 are independently hydrogen or an organic radical containing a photopolymerizable olefinic double bond, provided at least one of R.sub.2 and R.sub.3 is said organic radical,
- R.sub.4 and R.sub.5 are independently, a hydrocarbon having 1 to 8 carbon atoms, perfluoro, or a perhalofluoro aliphatic group having 1 to 8 carbon atoms, or together, R.sub.4 and R.sub.5 form an oxo group,
- m is 0 or 1, and
- n is a positive integer corresponding to the number of units in the polymer and is sufficiently large to provide said resin a) with a number average molecular weight of at least about 1500.
A lithographic printing plate comprising an anodized or grained aluminum support and having thereon a photosensitive image-forming layer and a protective overcoat layer, said photosensitive image-forming layer comprising:
- a) a polyamide containing ethylenically unsaturated photocrosslinkable groups,
- b) pentaerythritol triacrylate,
- c) a photocrosslinkable polyester resin containing aromatic groups and photosensitive --CH.dbd.CH--CO-- groups,
- d) a halogenated triazine photoinitiator, and
- e) as a photosensitizer, selected from the group consisting of N-methyl-2-benzoylmethylene-.beta.-naphthothiazoline, N-ethyl-2-benzoylmethylene-.beta.-naphthothiazoline, N-methyl-2-(m-sulfonylbenzoyl)methylene-.beta.-naphthothiazoline pyridinium salt, N-methyl-2-m-chlorobenzoylmethylene-.beta.-naphthothiazoline, N-methyl-2-p-nitrobenzoylmethylene-.beta.-naphthothiazoline, and N-methyl-2-bis(1'-furanoyl)methylene-.beta.-naphthothiazoline,
- the weight ratio of the total of said resin a) and resin c) to said monomer b) being from 2.25:1 to 4:1,
- said resin a) having structure XII:
- ##STR18## wherein R.sub.1 is phenylene or phenyleneoxyphenylene, R.sub.2 and R.sub.3 are each --CH.sub.2 CH.sub.2 OCO(CH.sub.3).dbd.CH.sub.2,
- n is a positive integer corresponding to the number of units in the polymer and is sufficiently large to provide said resin a) with a number average molecular weight of from about 1500 to about 35,000.
Dependencies are inferred from the claim text.