GB1566405A

GB1566405A - Photosensitive materials

Info

Publication number: GB1566405A
Application number: GB476576A
Authority: GB
Original assignee: Kodak Ltd
Current assignee: Kodak Ltd
Priority date: 1977-02-07
Filing date: 1977-02-07
Publication date: 1980-04-30

Description

(54) PHOTOSENSITIVE MATERIALS (71) We, KODAK LIMITED, a Company registered under the law of England, of Kodak House, Station Road, Hemel Hempstead, Hertfordshire, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement:- This invention relates to photosensitive materials comprising a photosensitive polymer layer and particularly to such materials which can be used as presensitized lithographic printing plates.

In British Patent Application No. 51941/73 (Serial No. 1463816) there is described and claimed a photosensitive material which comprises a support and a layer comprising a polymer containing repeating units containing a polyhalogen group having two or three halogen atoms bonded to the same carbon atom and repeating units containing an olefinically unsaturated group and comprising at least one metal carbonyl or metal carbonyl derivative.

We have now found a class of sensitisers which will sensitise the photosensitive material described above.

According to the present invention there is provided a photosensitive material which comprises a support and a photosensitive layer comprising (1) a polymer containing repeating units containing a polyhalogen group having two or three halogen atoms bonded to the same carbon atom and repeating units containing an olefinically unsaturated group, (2) at least one metal carbonyl or metal carbonyl derivative and (3) at least one sensitiser which is (a) a monomethine or polymethine dye or a merocyanine dye without an open methine chain, (b) a pyrilium, thiapyrylium or selenapyrylium salt or (c) a xanthene dye Preferably the photosensitive material contains an oxygen-impermeable layer and the photosensitive layer is located between the support and the oxygenimpermeable layer. The preferred oxygen-impermeable layer comprises succinoylated polyvinyl alcohol.

The methine sensitiser (a) may be a cyanine, merocyanine or styryl dye, the cyanines including trinuclear cyanines, for example holopolar cyanines.

The methine sensitiser (a) preferably has one of the formulae:

wherein R' and R2 are each a substituted or unsubstituted alkyl or aryl group, each L is hydrogen or an alkyl, aryl or heterocyclic group, Z' and Z2 each represent the atoms necessary to complete a heterocyclic nucleus which may contain substituents and/or further fused rings, Z3 represents the atoms necessary to complete a cyclic nucleus which may contain hetero atoms and/or further fused rings and/or may contain substituents, m and n are each 0, 1, 2 or 3, and X- is an anion and wherein the open methine chain may be interrupted by carbocyclic or heterocyclic rings.

The pyrylium sensitiser (b) preferably has the formula:

wherein X is an oxygen, sulphur or selenium atom, R3, R4 and R5 are each a substituted or unsubstituted alkyl, aryl, styryl, aryloxy or alkoxy group Y is an anion, preferably perchlorate.

The xanthene sensitiser (c) preferably has the formula:

wherein R6 and R7 are each a hydrogen or halogen atom or a hydroxy group or R6 and R7 together represent a disulphide bridge, R8 and R9 are each a hydrogen or halogen atom or a nitro group, R10 is hydrogen or up to four halogen atoms, M' is hydrogen or an alkali metal or ammonium cation and M2 is hydrogen or an alkyl group or an alkali metal or ammonium cation.

The sensitisers (a), (b) and (c) may be prepared by methods which are well known. Many are referred to in standard textbooks and/or the Colour Index.

The photocrosslinkable polymers which may be employed in the present invention and their preparation are fully described in our copending Application No. 51941/73, (Serial No. 1463816) are the metal carbonyls and their derivatives.

Preferably, the weight ratio of polymer to metal carbonyl in the photographic materials of the present invention is from 10:1 to 100:1 although larger or smaller amounts of metal carbonyl may be used if desired.

The amount of sensitiser to be used will vary widely and should be determined by experiment. However amounts of from 0.25 to 0.65 times the weight of metal carbonyl compound used are preferably employed.

Preferably, the photographic materials of the present invention contain in the sensitive layer a plasticiser which is a polyunsaturated monomeric compound.

Particularly useful compounds are pentaerythritol tetra-acrylate (Sold under the trade name SR295 by Sartomer Industries Inc.), tetraethylene glycol dimethacrylate (Sold under the trade name SR209 by Sartomer Industries Inc.) and trimethylol propane trimethacrylate (Sold under the trade name SR350). The plasticiser is preferably used in an amount of 1 part to 6.25 parts per 100 parts of photosensitive mixture or 8 parts to 20 parts of plasticiser per 100 parts by weight of the polymer.

The photographic materials of the present invention may contain other addenda such as print-out or bleach-out materials to provide a visible image on exposure and antioxidants to improve keeping quality. Example of print-out materials are leuco triphenylmethane dyes. Leuco crystal violet, leuco malachite green and leuco propyl violet are particularly useful and provide an acceptable image even on short exposures e.g. 2 to 3 seconds to a high pressure mercury vapour lamp (4x150 watts) at 18 inches.

The photographic materials of the present invention are useful in the preparation of resist images. In one application they are in the form of presensitised lithographic printing plates in which the support is formed of a hydrophilic material such as anodised aluminium. In another application they are in the form of photoresist materials in which the support comprises a metal layer such as a laminated copper support.

In use, the materials are exposed to actinic radiation so as to render the exposed areas relatively insoluble compared to the unexposed areas. The material is then solvent developed such as by means of a swab to remove the unexposed areas and leave the insoluble areas. The photographic materials of the invention may be developed in organic or aqueous solvents. The use of aqueous solvents is preferred and a particularly useful aqueous solvent comprises sodium hydroxide dissolved in aqueous ethanol.

Further increases in sensitivity or photographic speed can be obtained by heating the photosensitive material in the absence of oxygen after imagewise exposure and before development.

The present invention also provides a photosensitive composition comprising (1) a polymer containing repeating units containing a polyhalogen group having two or three halogen atoms bonded to the same carbon atom and repeating units containing an olefinically unsaturated group, (2) at least one metal carbonyl or metal carbonyl derivative and (3) at least one sensitiser which is (a) a monomethine or polymethine dye, or a merocyanine dye without an open methine chain, (b) a pyrilium, thiapyrylium or selenapyrylium salt or (c) a xanthene dye.

The following preparations and Examples are included for a better understanding of the invention. Examples 1, 3-5 and 7-8 are comparative. The words Waring, Moviol, Kodak, Photoflo and Polymatic are Trade Marks. Some results are illustrated in Figs. 1--3 of the drawings accompanying the Provisional Specification.

Preparation 1 Terpoly methyl methacrylate, acrylic acid, hydroxyethyl methacrylate) (9:1:2).

A 1 litre multi-necked flask was fitted with a stirrer, thermometer, nitrogen inlet tube, a dropping funnel and a condenser. 1,2-Dichloroethane (400 ml) was placed in the flask which was immersed in a thermostatically controlled oil bath.

Stirring was started and nitrogen was slowly bubbled through the solvent. The bath was heated until the solvent began to reflux when a solution of methyl methacrylate (90 g), acrylic acid (7.2 g), hydroxyethyl methacrylate (26 g) and azo di-iso butyronitrile (1.23 g) in l,2-dichloroethane (100 ml) was added dropwise over 45 minutes. After the addition was complete, heating under reflux in a nitrogen atmosphere was continued for 16 hours. The polymer solution was then allowed to cool, and the polymer was precipitated by slowly pouring the solution into ether (2.51) which was thoroughly stirred. The colourless slightly fibrous solid was washed with a fresh portion of ether, collected and dried in a vacuum at room temperature, yield 110 g. The polymer had a log viscosity number of 17 (cyclohexanone at 250C) and an acid number of 42.4 (Theoretical 46.2).

(CH98O26)n require C, 58.44; H, 7.79% found C, 57.6; H, 7.9% Preparation 2 Reaction of tribromoacetyl bromide and methacryloyl chloride with terpoly (methylmethacrylate, acrylic acid, hydroxyethylmethacrylate) (3:1).

Terpoly (methyl methacrylate, acrylic acid, hydroxyethyl methacrylate (Preparation 1) (12.32 g) was dissolved with stirring in 1,2-dichloroethane (125 m in a 3 necked, 250 ml round bottomed flask fitted with a stirrer, a thermometer, two dropping funnels and an air condenser carrying a calcium chloride tube. The apparatus was placed in an ice/salt bath and the solution was cooled to -50C.

Triethylamine (0.56 g) was added through one dropping funnel, followed by tribromoacetyl bromide (1.80 g) through the other funnel. After stirring for 30 minutes, a further quantity of triethylamine (1.58 g) was added, followed by methacryloyl chloride (1.56 g). Stirring was now continued for two hours, at first at -5"C and then the solution was allowed to warm up to +50C. The precipitated triethylamine hydrochloride was then filtered off, and the polymer was precipitated by slowly pouring the solution into rapidly stirred ether (2 1). The polymer was washed with a fresh portion of ether and was then collected by filtration. It was dried under vacuum. Next, the polymer was suspended in water (1 litre) and stirred for 1 hour. It was again filtered off and dried under vacuum. The polymer was then redissolved in 1 ,2-dichloroethane and reprecipitated into ether. It was washed with ether, dried under vacuum Yield (11.5 g). Log viscosity number 18. (cyclohexanone at 25"C).

(C134H203Br3Os6)n require C, 54.56; H 6.89; Bur, 8.14% found C, 54.4; H, 7.0; Br, 8.04% Preparation 3 Poly(vinyl alcohol) succinate.

Poly(vinyl alcohol) (Moviol 4-98; 44g) was dissolved in dimethylformamide (200 ml) by stirring a suspension of the polymer in the solvent in a 500 ml round bottomed flask, fitted with a stirrer and condenser. The flask was placed in an oil bath and heated to 1700C (bath temperature) to effect solution. Succinic anhydride (3.5 g) was dissolved in dimethylformamide (10 ml) and this solution was heated to 80"C and wasthen added to the poly(vinyl alcohol) solution. Stirring and heating were continued for 15 minutes. The solution was allowed to cool for a few minutes. It was then poured slowly into stirred acetone (2.5 1) when the polymer precipitated as a fibre. The fibrous mass was broken up, by macerating the polymer with fresh portions of acetone in a 'Waring' blender. The polymer was collected and dried under vacuum at room temperature. A sample was dissolved in water and titrated against standard sodium hydroxide solution, using phenolphthalein as indicator.

The polymer had an acid number of 22.8 (acid number=mg of KOH needed to neutralize Ig of polymer).

Example 1 A coating composition was made as follows: Polymer described in Preparation 2 as a 10% solution in dichloroethane 5 ml Benzene tricarbonyl chromium as a 10% solution in dichloroethane 0.25 ml This formulation was coated onto a 5"x5" grained, phosphoric acid anodized aluminium foil, which was unsubbed, on a whirler coating machine at 150 rpm.

The coating was overcoated with the following formulation: Polymer described in Preparation 3 as a 10% solution in water 20 ml Propionic acid 0.01 ml Kodak Photoflo 200 0.02 ml A part of the plate was exposed for five minutes through a 0.1 log E units/mm continuous-tone silver wedge and high radiance monochromator (Model M300, Applied Photophysics) to a 250 W xenon arc lamp (Model 442, Applied Photophysics). The plate was then heated for five seconds with a hot-air drier (nozzle temperature was about 160"C and the nozzle was kept an inch from the plate).

The exposed coating was then developed in a solvent mixture composed of: Propylene carbonate 60 ml Butyrolactone 20 ml 100/, Citric acid in water 40 ml Phosphoric acid (sp.g.1.75) 1 ml After removal of the unexposed areas, the non-image areas were desensitized with Kodak Polymatic Desensitiser Gum solution and the plate was inked. The resulting wedge spectrograph is shown in Figure la.

Example 2 A coating composition was made as follows: Polymer described in Preparation 2 as a 10% solution in dichloroethane 5 ml Benzene tricarbonyl chromium as a 10% solution in dichloroethane 0.25 ml The cyanine dye of the formula below 0.01 g

This formulation was coated, overcoated, exposed and developed as in Example 1 and the resulting wedge spectrograph is shown in Figure Ib, indicating spectral sensitisation to 570 nm.

Example 3 A coating composition was made as follows: Polymer described in Preparation 2 as a 10% solution in dichloroethane 5 ml Cyanine dye used in Example 2 0.01 g This formulation was coated, overcoated, exposed and developed as in Example I and the resulting wedge spectrograph is shown in Figure lc, indicating slight sensitisation 450 nm-540 nm.

Example 4 A coating composition was made as follows: Polymer described in Preparation 2 as a 10% solution in dichloroethane 5 ml The polymer was coated, overcoated, exposed and developed as in Example 1. No image was recorded.

Example 5 The formulation of Example 1 was coated, overcoated, exposed and developed as in Example 1. The resulting wedge spectrograph is shown in Figure 2a.

Example 6 A coating composition was made as follows: Polymer described in Preparation 2 as a 10% solution in dichloroethane 5 ml Benzene tricarbonyl chromium as a 10% solution in dichloroethane 0.25 ml The thiapyrilium salt of the formula below 0.01 g

This formulation was coated, overcoated, exposed and developed as in Example 1 and the resulting wedge spectrograph is shown in Figure 2b, indicating spectral sensitisation to 570 nm.

Example 7 A coating composition was made as follows: Polymer described in Preparation 2 as a 10% solution in dichloroethane 5 ml Thiapyrilium salt I of Example 6 0.01 g This formulation was coated, overcoated, exposed and developed as in Example 1 and the resulting wedge spectrograph is shown in Figure 2c, indicating very slight sensitisation.

Example 8 The formulation of Example 1 was coated, overcoated, exposed and developed as in Example 1. The resulting wedge spectrograph is shown in Figure 3a.

Example 9 A coating composition was made as follows: Polymer described in Preparation 2 as a 10% solution in dichloroethane 5 ml Benzene tricarbonyl chromium as a 10% solution in dichloroethane 0.25 ml Erythrosine B (which has the formula given below) 0.01 g

This formulation was coated, overcoated, exposed and developed as in Example 1 and the resulting wedge spectrograph is shown in Figure 3b, indicating spectral sensitisation to 600 nm.

Example 10 A coating composition was made as follows: Polymer as described in Preparation 2 as a 10G solution in dichloroethane 5 ml Erythrosine B 0.01 g This formulation was coated, overcoated, exposed and developed as in Example 1 and the resulting wedge spectrograph is shown in Figure 3c, indicating slight sensitisation 480 nm-580 nm.

WHAT WE CLAIM IS: 1. A photosensitive material which comprises a support and a photosensitive layer comprising (1) a polymer containing repeating units containing a polyhalogen group having two or three halogen atoms bonded to the same carbon atom and repeating units containing one olefinically unsaturated group, (2) at least one metal carbonyl or metal carbonyl derivative and (3) at least one sensitiser which is (a) a monomethine or polymethine dye or a merocyanine dye without an open methine chain, (b) a pyrilium, thiapyrilium or selenapyrilium salt or (c) a xanthene dye.

2. A photosensitive material as claimed in Claim 1 which contains an oxygenimpermeable layer and the photosensitive layer is located between the support and the oxygen-impermeable layer.

3. A photosensitive material as claimed in Claim 2 in which the oxygenimpermeable layer comprises succinoylated polyvinyl alcohol.

4. A photosensitive material as claimed in any of Claims 1--3 in which the sensitiser is a methine sensitiser having one of the formulae:

5. A photosensitive material as claimed in any of Claims 1-3 in which the sensitiser is a pyrilium sensitiser of the formula:

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **. This formulation was coated, overcoated, exposed and developed as in Example 1 and the resulting wedge spectrograph is shown in Figure 3b, indicating spectral sensitisation to 600 nm. Example 10 A coating composition was made as follows: Polymer as described in Preparation 2 as a 10G solution in dichloroethane 5 ml Erythrosine B 0.01 g This formulation was coated, overcoated, exposed and developed as in Example 1 and the resulting wedge spectrograph is shown in Figure 3c, indicating slight sensitisation 480 nm-580 nm. WHAT WE CLAIM IS:

1. A photosensitive material which comprises a support and a photosensitive layer comprising (1) a polymer containing repeating units containing a polyhalogen group having two or three halogen atoms bonded to the same carbon atom and repeating units containing one olefinically unsaturated group, (2) at least one metal carbonyl or metal carbonyl derivative and (3) at least one sensitiser which is (a) a monomethine or polymethine dye or a merocyanine dye without an open methine chain, (b) a pyrilium, thiapyrilium or selenapyrilium salt or (c) a xanthene dye.

wherein X is an oxygen, sulphur or selenium atom, R3, R4 and R5 are each a substituted or unsubstituted alkyl, aryl, styryl, aryloxy or alkoxy group, Y- is an anion.

6. A photosensitive material as claimed in any of Claims 1--3 in which the sensitiser is a xanthene sensitiser of the formula:

wherein R6 and R7 are each a hydrogen or halogen atom or a hydroxy group or R8 and R7 together represent a disulphide bridge, R8 and R9 are each a hydrogen or halogen atom or a nitro group, R'O is hydrogen or up to four halogen atoms, M1 is hydrogen or an alkali metal or ammonium cation and M2 is hydrogen or an alkyl group or an alkali metal or ammonium cation.

7. A photosensitive material as claimed in any of Claims 1--6 in which the weight ratio of polymer to metal carbonyl compound is from 10:1 to 100:1.

8. A photosensitive material as claimed in any of Claims 1--7 in which the sensitiser is present in amounts of from 0.25 to 0.65 times the weight of the metal.

carbonyl compound present.

9. A photosensitive material as claimed in any of Claims 1--8 in which the photosensitive layer contains a plasticiser which is a polyunsaturated monomeric compound.

10. A photosensitive material as claimed in Claim 9 in which the plasticiser is pentaerythritol tetra-acrylate, tetraethylene glycol dimethacrylate or trimethylol propane trimethacrylate.

11. A photosensitive material substantially as described herein and with reference to Examples 2, 6 and 9.

12. A photosensitive composition comprising (1) a polymer containing repeating units containing a polyhalogen group having two or three halogen atoms bonded to the same carbon atom and repeating units containing an olefinically unsaturated group, (2) at least one metal carbonyl or metal carbonyl derivative and (3) at least one sensitiser which is (a) a monomethine or polymethine dye, or a merocyanine dye without an open methine chain, (b) a pyrilium, thiapyrilium or selenapyrilium salt, or (c) a xanthene dye.

13. A photosensitive composition as claimed in Claim 12 wherein the sensitiser is one of those specified in any of Claims 4--6.

14. A photosensitive composition substantially as described herein and with reference to Examples 2, 6 and 9.