DE2446056A1 - WATER DEVELOPABLE PHOTO-SENSITIVE PLATE, ITS USE AND USEFUL PHOTOPOLYMERIZABLE COMPOSITIONS - Google Patents

Description

PATENT ADVOCATE BORO TiEDTKE ™ SüHLmG - chins TEL. (089) 53 96 53-58 TELEXt 524845 tlpat CABLE ADDRESS: Germaniapatent Munich O / / CQ Cg

8000 Munich 2

Bavariaring 4 P.O. Box 202403, September 26, 1974

case Q / M 26472 - B 6236

IfIPERIAL CHEMICAL INDUSTRIES LIMITED London S.W. 1. / England

Photosensitive plate, developable with water, whose Use and photopolymerizable compositions useful therefor

The invention relates to photopolymerizable compositions together with their preparation as well as their use in water-developable photosensitive plates and for the production of relief plates.

It is known that photopolymerizable compositions' set a soluble polymer material together with a contain addition polymerizable monomers. Such compositions can e.g. for the production of a

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Relief printing plate can be used by making a Layer or web of the composition exposed through a negative so that in the light struck Dividing the composition a further polymerization occurs and by subsequently leaving the unexposed Parts removed with a suitable solvent to the desired relief depth.

According to the invention there is now provided a photopolymerizable composition which is produced by treatment with water or 'an aqueous liquid can be developed (removal, unexposed areas).

The photopolymerizable composition of the present invention essentially comprises;

(a) a water-soluble or water-dispersible polymer or copolymer or a polymer or copolymer mixture, in which one or more of the components is or are water-soluble or water-dispersible;

(b) an addition polymerizable monomer, which is preferably although not necessarily insoluble in water, but in a solvent or dispersing agent Medium for (a) is soluble or compatible with these and

(c) a photoinitiator that is used to initiate polymerization of the monomer is capable, whereby the

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Composition can be made water-insoluble with suitable irradiation.

Typical water-soluble polymers include polyacrylic acid, Polymethacrylic acid, polyvinyl alcohol, hydroxyethyl cellulose, polyvinyl pyridine, sulfonated polystyrene and partially hydrolyzed polyvinyl acetate.

Component (a) comprises a water-soluble polymer either alone or mixed or copolymerized with one or more less water-soluble polymers or monomers (depending on suitability) j for the polyacrylates, polyalkyl acrylates (e.g. polymethyl acrylate, 2-ethylhexyl acrylate), polyalkyl methacrylate (e.g. Polymethyl methacrylate, lauryl methacrylate), dialkyl maleates (e.g. di-iso-octyl maleate, di-butyl maleate or diethyl maleate) Examples are.

The selection of the constituent or constituents of component (a) is made with regard to the requirement that they can be washed off from a film of material using an aqueous liquid, preferably water should be, that is, it should be water soluble or water dispersible. The composition is preferable also in an alcohol or another suitable solvent to facilitate shifting

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or film formation soluble.

The applicant's preferred component (a) comprises poly (N-vinylpyrrolidor) - alone or mixed with polyvinyl acetate - or a copolymer of N-vinylpyrrolidone and vinyl acetate. Poly (N-vinylpyrrolidone) and the copolymers of N-vinylpyrrolidone and vinyl acetate are both soluble in water and in lower alcohol (e.g. methanol and ethanol), which has been considered advantageous since the formation of a film from the composition of the invention from a solution in one of the lower alcohols (ie up to C ^) is preferably ^f .

Component (a) will usually be present in the composition in an amount which constitutes 50 to 95% by weight, the water-soluble polymer preferably constituting 30 to 70 % of the total amount of (a).

The monomer used is preferably, although not necessarily, water-insoluble. It is natural it is desirable that the monomer be highly compatible with the polymer and any other components of the composition and is able to with at least one of the component (s) (a) to form a water-insoluble product polymerize. Preferably the monomer comprises at least

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two non-conjugated ethylenic double bonds and it is preferably terminally unsaturated.

Examples of suitable monomers include:

(1) \ O / ^N ( ^CH 2 ^CH 2 ^OC - ^c * CH ₂ ) ₂

where R = H or CH, and the benzene ring can contain one or more substituents, which can be identical or different and which include alkyl groups with up to 4 carbon atoms, -COOH, halogen and -COOR ₁ , where R _{1 is} a lower alkyl group (ie with up to 4 carbon atoms), as well as -SO ₂ NR ₂ R, or -CONR ^ R, -, where R ₂ , R *, R ^ and R ₁ - each can mean H or a lower alkyl group . Examples are: N, N-bis- (ß-acryloyloxyäthy1) -aniline N, N-bis- (ß-methacryloyloxyethyl) -m-toluidine N, N-bis- (acryloyloxyäthyl) -chloraniline.

R R

(2) CH ₂ = C - CONH (CH _{2) 3} 0 (CH _{2) 2} 0 (CH ₂ J ₃ HNOC-C =

with R »H or CH ,.

For example, l, 2-bis (γ -acrylamidopropoxy) -ethane 1,2-bis- (γ -methacrylamidopropoxy) -ethane

(3) acrylates,
e.g. allyl methacrylate

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Ethylene glycol dimethacrylate
Trimethylolpropane triacrylate trimethylolpropane trimethacrylate pentaerythritol tetraacrylate
Pentaerythritol monohydroxy triacrylate.

• (4) vinyl urethanes,

e.g. a reaction product of di (4-isocyanatophenyl) methane, Polypropylene glycol and 2-hydroxyethyl methacrylate in a molar ratio 2: 1: 2.

a reaction product of tolylene diisocyanate, pentaerythritol / propylene oxide adduct and 2-hydroxyethyl methacrylate in a molar ratio of 1:45

(5) allyl monomers
for example triallyl cyanurate.

The proportion of the monomer in the composition will vary within wide limits, but will usually be within the range from 5 to 50% by weight , preferably 10 to 25% by weight of the composition.

It should be noted, although not preferred, that component (b) could be an oligomer, i.e., a short-chain polymer with up to - say - five repeating monomer units, if such a connection is adequately unsaturated and polymerizable, such as

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was set out above.

Suitable photoinitiators include those described in the literature as being suitable for initiating polymerizations by generating free radicals. Preferably they are activated by actinic radiation, usually in the 300-450 nm wavelength range, although it should be understood that other forms of electromagnetic radiation outside the visible range. can be used and the term photoinitiator is not limited to light-sensitive initiators alone. Examples of preferred photoinitiators are benzophenone, benzoin, benzoin methyl ether and substituted benzyl methyl ether and diacetyl. These are expediently used in concentrations in the region of 0.1 to 10 %, preferably 1 to 8% by weight of component (a).

An application of the compositions according to the invention consists in the production of relief plates, which after appropriate Processing for direct or offset text printing, flexographic printing or as a model or. Sample plates usable are.

When producing such printing plates, the composition according to the invention is applied to a suitable carrier

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applied to form a film of precisely controlled thickness. The carrier can be made of a suitable metal but also made of glass or plastic (e.g. polyethylene terephthalate) etc. When the wearer is in use must be deformed as when applying to a pressure cylinder, a suitably flexible carrier is required and the carrier material is selected with this in mind Requirement. The carrier material chosen is, of course, one that is determined by the processing operations to which the plate is subjected, is not adversely affected.

The film thickness of the composition on the support depends on the intended use of the plate, however, dry film thicknesses between 0.13 and 1.30 mm have generally been used.

Better results can be obtained by first treating the carrier material with a "wedging" Coating layer that is essentially a compatible adhesive capable of promoting adhesion between Carrier and composition and is water resistant. A thin film (less than about 5 Ju) of polyvinyl acetate tends to improve the adhesion to the carrier and to a better (opt) dissolution

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may result in the final panel because of fine detail, otherwise because of the limited area of contact would be washed away with the wearer, is retained.

On some substrates (e.g. polyester film) where the adhesion is poor, the relief image can move or tend to shift during drying after development. This tendency for image movement can can be reduced by contacting the image with a solution which has some of the washing liquid through Can remove osmotic effects. The applicant prefers to use a concentrated one for this purpose aqueous solution of an inorganic salt such as sodium sulfate; the solution is preferably saturated. Solutions of such inorganic salts can also can be used to develop the plate.

In addition to the components already listed, it may be desirable to incorporate a heat crosslinking inhibitor into the composition to prevent polymerization by heat . Hydroquinone and related compounds can be used in reasonably effective amounts. Plasticizers can also advantageously be incorporated into the composition, and the person skilled in the art will have no difficulty choosing from those described in the literature. The addition of suitable color

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fabrics may also be preferred to reduce light scattering during exposure. Surface active Agents can also be incorporated into the composition to improve uniformity Flowing with the layer application.

The invention is illustrated below by means of examples further explained.

example 1

1: 1 copolymer of vinyl acetate and N-vinylpyrrolidone as a 60% (w / w) solution in ethanol '166.7 g of ethylene glycol dimethacrylate 20, above

Dimethyl phthalate (plasticizer) x 10.0 g benzophenone. 2.5 g

The benzophenone was in the mixture of ethylene glycol dimethacrylate and dimethyl phthalate are dissolved, and this solution is added to the copolymer solution with stirring. This solution was allowed to stand for a few hours for deaeration. "Hi Top" steel was used as the carrier material (Steel, coated with chromium / chromium oxide) is used. The solution was taken on this support with 1.5 mm wet thickness Using a squeegee · (doctor blade with a fixed gap) spread out. The coating was obtained with a

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Dry film thickness of 0.7 mm dried in the oven. To
after drying, the film thus obtained was through a
Halftone line negative for 12 minutes with UV light from 20 watt UV fluorescent tubes at a distance of 7.6 cm from
the plate irradiated. The exposed Platte'wurde then 3 1/2 minutes long washed with sprayed water of 24 ⁰ C. After the plate had dried, a relief image of approximately 0.6 mm was obtained. The plate was mounted on a printing machine text and _f were obtained satisfactory few thousand copies.

Example 2

The composition corresponded to Example 1, except that 0.6 g of "Lissapol N" was added as a surface-active agent. This solution was applied to aluminum sheets to achieve a dry thickness of 0.7 mm.
The plate was exposed to UV light through a line negative for 10 minutes as in Example 5 and washed out for 3 minutes to achieve a relief image of approximately 0.6 mm.

Example 3

The composition was the same as Example 1, except that diallyl phthalate was used instead of dimethyl phthalate became.

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Example 4

The composition corresponded to Example 1, only that "Cereclor 50 LV" (chlorinated paraffin from ICI) instead of dimethyl phthalate was used.

Example 5

"Luviskol VA 55 E" * 20 g

N, N-bis (ß-acryloyloxyethyl) aniline 2.5 g, methanol 2.5 g

Benzophenone 0.5 g

* "Luviskol VA 55 E" is a copolymer of equal parts of N-vinylpyrrolidone and vinyl acetate, which is 50 wt Solution in ethanol is supplied.

The above components were mixed together and stirred until the benzophenone dissolved. The solution was then applied to a support (polyethylene terephthalate sheet 0.18 mm thick) with a pull rod or wire bar to achieve a 1.0 mm wet film thickness. The film was then dried at a temperature of about 50 ⁰ C.

The film obtained in this way was exposed to a UV source for 10 minutes (2 Philips MLU? 00 W lamps at a distance of 51 cm) exposed by a negative with the types to be reproduced corresponding to the transparency. The exposed plate

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was then under a cold water tap for 2 minutes (In an alternative experiment, an ultrasonic bath containing water was used for about 45 seconds). A relief image approximately 0.3 mm high has been received"

Washed under the tap while drying Plate there was a certain shift or movement of the relief image. A similar record was immersed in a saturated aqueous solution of sodium sulfate for 2 minutes after washing. After this Drying, the plate was subjected to a brief rinse with water to remove surface crystals and then dried. There was no shift in the relief image.

Example 6

* »Luviskol VA 37 E" 20 g

Trimethylolpropane trimethacrylate 0.9 g benzophenone 0.5 g

* "Luviskol VA 37 E" is a copolymer with N-vinylpyrrolidone and vinyl acetate comonomers in a ratio of 3: 7, which is supplied as a 50% by weight solution in ethanol.

The above components "were produced as in Example 1

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-W-

mixes and the solution on a carrier (aluminum foil 0.13 mm thick) with a wire doctor to achieve a 1 mm wet film thickness.

The film was dried and subsequently exposed as described in Example 1 and then for 4 1/2 minutes long developed in an ultrasonic bath containing water at room temperature. In this way it became a relief image obtained approximately 0.35 mm high.

Example 7

* "Luviskol VA 64» 10 g '

Ethylene glycol dimethacrylate 2.5 g

Dimethyl phthalate 2.0 g

Benzophenone 0.5 g

"Nylomine acid black D-R" 0.75 mg

Industrial denatured spirit 10 g

* "Luviskol VA 64" is a copolymer whose comono-

mere N-vinylpyrrolidone and vinyl acetate in the ratio

6: 4 are available.

A solution of polyvinyl acetate in industrial denatured alcohol was made with a wire bar. on a 0.13 mm thick aluminum foil applied to create a "wedging" layer of 2yu dry density.

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The composition described above was then panned onto the aluminum support with a wire bar to achieve a 1 mm wet film thickness. After drying, the film thus obtained became that in Example for 15 minutes 5 through a transparent negative for the types to be reproduced. The exposed plate was then washed under a cold water tap for 3 minutes and a relief image of approximately 0.3 mm high.

Example 8

* "Luviskol VA 73 E" ■ 20 g

Allyl methacrylate 2.5 g

Dimethyl phthalate 1.5 g

Benzophenone 0.5 g

* "Luviskol VA 73 E" is a copolymer with N-vinylpyrrolidone and Vinyl acetate comonomers in a ratio of 7: 3, supplied as a 50% strength by weight solution in ethanol will.

The above components were mixed as in Example 1 and the solution was applied to a support (aluminum foil 0.13 mm thick with a wedging layer as in Example 7 described) applied with a wire doctor to achieve a 1 mm wet film thickness.

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The film was dried and subsequently, as in
Example 1 described, exposed and washed under a Kal.twasserhahn for 2 minutes. A relief image approximately 0.3 mm high was thus obtained.

Example 9

A mixture of vinyl pyrrolidone (100 g), vinyl acetate (80 g), diisooctyl maleate (20 g) and azobisisobutyronitrile (2 g) was added over a period of 30
Minutes to industrial denatured alcohol (160 g)
added at reflux under a nitrogen blanket. The mixture was refluxed for a total of 8 hours to give a viscous solution.

180 g of the terpolymer solution prepared as above
were added to a mixture of ethylene glycol dimethacrylate (20 g) and benzophenone (2.5 g). A portion of this solution was poured onto a steel sheet and
Dried for 2 hours at 85 ° C. to give a coating of 0.6 mm thick. The plate was flexible enough to be bent around an arc of 5 cm in diameter. The dried plate was exposed to UV radiation through a negative on a vacuum frame for 7 minutes and then washed with tap water for 23 ^ 5 minutes to give one for uses such as

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Relief image suitable as a text printing plate.

Example 10

A mixture of vinyl pyrrolidone (125 g) _f vinyl acetate (75 g), diethyl maleate (50 g) and azobisisobutyronitrile (2.5 g) was added over a period of 30 minutes to industrial denatured alcohol (250 ml) at reflux under a nitrogen blanket. The mixture was refluxed for a total of 8 hours.

90 g of the terpolymer solution prepared as above was added to a mixture of ethylene glycol dimethacrylate (5 g), benzophenone (1.25 g) and "Lissapol N" (0.5 g). A portion of this solution was poured on an aluminum sheet and dried at 85 mm ⁰ C to obtain a tack-free coating of 0.45 thickness. The dried plate was placed on a vacuum frame 71/2. Minutai long exposed to UV radiation through a halftone negative and then washed ^{with tap water at 18 0} C to achieve a relief image suitable for text printing. The record was before. and flexible after processing.

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Claims (1)

, fg- 24A6056 Claims Photopolymerizable composition characterized by (a) a water-soluble or water-dispersible polymer or copolymer or a polymer or copolymer mixture, in which one or more components ^) is or are water-soluble or water-dispersible; (b) an addition polymerizable monomer which is in a Solvent or dispersing medium for (a) is soluble or compatible therewith and (C) a photoinitiator capable of initiating the polymerization of the monomer, through whose mediation the addition. can be made water-insoluble by irradiation * 2. Composition according to claim I _8, characterized in that component (a) comprises poly (N-vinylpyrrolidone). 3. Composition according to claim 2, characterized in that component (a) is also polyvinyl acetate includes. U, composition according to claim 1, characterized in that component (a) is a copolymer of 509814/0900 Poly (N-vinyl pyrrolidone) and vinyl acetate. 5. Composition according to one of the preceding claims, characterized in that the photoinitiator by actinic radiation in the wavelength range of 3CO can be activated up to 450 nm. 6. Composition according to one of the preceding claims, characterized in that component (b) is a monomer that has at least two non-conjugated includes ethylenic double bonds. 7. Water-developable photosensitive plate, characterized by a photopolymerizable composition according to any one of the preceding claims and a carrier. 8. Use of the photosensitive plate according to claim 7 for the production of a relief plate by imagewise Exposure to electromagnetic radiation and washing out the exposed plate with water or aqueous media Liquid for removing unexposed parts of the photopolymerizable composition. 5098U / 0900