DE2211814A1 - Photosensitive composition for presensitized printing plates - Google Patents

Description

DR. E. WIEGAND DIPL-ING. W. NIEMANN

DR. M. KÖHLER DIPL-ING. C. GERNHARDT 221 1 8 1

MDNCHEN HAMBURG

TELEPHONE: 555 476 8000 MÖN CHEN 15

TELEGRAMMER CARPATENT NUSSBAUMSTRASSE 10

W 41 054/72 ^'10 · ^{March 1972}

Fuji Photo For. Co., Ltd.
Ashigara-Kamigun, Kanagawa (Japan)

Photosensitive composition for presensitized printing plates

The invention relates to a photosensitive composition for presensitized Printing plates,

The vast majority of photosensitive materials used in presensitized printing plates are Diazonium compounds and most commonly diazo resins are used in the condensation of p-diazophenylamine and foxraaldehyde can be obtained. These resins are commercially available under the trade name !! "Diazo Lith No. 1" (from Ringwood-Chemical Corp.), "Diazo Resin No. 4" (from Fairmount. ChtunicaI Corp.) and the like available and easily accessible = These Resins are applied in the form of a layer to suitable supports, for example paper, plastic or metals, and the

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carrier obtained are exposed through a transparent negative actinic light, the exposed portion is the diazo "resin rendered insoluble due to the decomposition of the diazo resin. On the other hand, the non-Y-exposed part is washed off with water, whereby the Oberflächt- the wearer is exposed. If If a support is used, the surface of which has previously been made hydrophilic by a treatment, this hydrophilic layer is exposed when the non-exposed part is developed the decomposed part of the diazo resin is made hydrophobic, making it water-repellent and receptive to ink. That is, such printing materials lead to so-called negative-working printing plates.

These types of photosensitive printing materials are classified into two groups, one in which a diazo resin is used alone, that is, without a support (as described, for example, in US Pat. No. 2,714,066) and another group in using a carrier (as described, for example, in US Pat. No. 2,826,501 and British Pat. No. 1,074,392). In the former case, the thickness is

2 applied light-sensitive layer about 20 to 100 mg / m ', since no carrier is used and the image part is pre-strengthened (solidified) because the resulting image is subject to abrasion and only has a poor durability (Shelf life), mfweiüL. The general day resin is added after or at the same time as; the wrapping is selectively fixed on the image part using an emuig Lectori varnish in order to prevent the various types of abrasion and peeling off during printing, see above; ß a number of prints (prints) is obtained. The gap used for this purpose must have an excellent Abri-bbesL-änr;!; ·

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they have to adhere lightly to the part of the picture and only difficult to form foam, bridging, and the like. Devices have already been developed which meet these requirements suffice (see e.g. U.S. Patent 2,754,279). However, from the user (consumer) of printing plates Varnishes are applied and this work requires great skill, since the quality of the printing plate depends to a large extent on whether the paint is applied well or poorly. In order to overcome this disadvantage, it has been proposed to use a resin beforehand to be incorporated into a sensitive layer together with a light ™ sensitive material with good abrasion resistance and thereby hardening the incorporated resin together with the light decomposition of the diazoiiium compound (cf., for example, the US * * U.S. Patent 2,826,501 and British Patent 1,074,392). Therefore, a resin used for such a varnish coating corresponds, mixed with a light-sensitive diazo compound, in order to achieve a layer of sufficient thickness (1.5 g / m) at the beginning and during the development process the over « liquid part, i.e. the non-hardened part, from the surface of the carrier is removed due to the difference in solubility between the non-hardened part and the hardened part, whereby an effect equal to or greater than that obtained when a varnish is applied after development is obtained will.

When incorporating a resin, however, the compatibility of the incorporated resin with the diazo light-sensitive material is important and the choice of a common solvent is important. In addition, either the entire photosensitive layer, the containing a resin as a carrier by photolysis. the photosensitive Material must be made insoluble or it must be a clearer one

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Difference in the solubility or the degree of swelling between the exposed part and the non-exposed part. In addition, a resin used as a support must have sufficient shelf life in the presence of a diazo light-sensitive material to have. A certain water-soluble colloid provides when used as a carrier for a photosensitive Diazo material is a resist material with a very good quality, but it deteriorates within a few days by dark reaction and loses sensitivity. Until now different types of materials have already been proposed which meet these requirements, but these do not meet the desired properties of curing effectiveness, durability, lipophilic property and storage stability. From the above it can be seen that the selection of the resin is extremely important in the manufacture of printing materials.

It is therefore an object of the present invention to provide a photosensitive mass (composition) which can be used for sensitized printing materials are suitable, which have excellent mechanical strength over the entire sensitive layer having. Another object of the invention is to provide a photosensitive composition and a printing material using the same Contains mass and has an excellent shelf life.

The above objects are achieved when using a photosensitive diazo compound and shellac as a carrier for the photosensitive material used.

The term "light-sensitive diazo compounds" used here is to be understood as meaning diazo compounds in the broadest sense,

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" ⁵ " 22118U

for example diazonium salts, p-diazooxides, p-diazoimines and like that. Particularly preferred photosensitive diazo compounds are those which are sufficient in organic solution mat In are soluble and contain several diazo groups in one molecule, such as condensates of diazonium salts and formaldehyde. The diazo compounds described, for example, in US Pat. No. 2,649,373 are particularly suitable. These. For example, diazo compounds have the following general formula:

V Δι- TJ Y

where mean:

R is an aryl, aralkyl, higher alkyl or aroyl radical,

Y 0, S, NH or NIL, where R, alkyl, aralkyl or aryl,

Ar is an aromatic residue

X is an equivalent of an anion of an acid.

The term "aroyl" used here includes all acyl radicals of aromatic carboxylic acids, e.g. benzoyl, and the expression "equivalent of an anion of an acid" means residues

- SO 'ZnCl -

stand, such as Cl, 4 , 4 , C ₆ H ₅ SO ₃ and the like.

The substituent Y and the diazo group N ~ can preferably be in p-position to each other. The aromatic residue Ar, the Group R and NH group can contain further substituents. In most cases it is advantageous if the radicals R and Ar by alkoxy, aroxy or N-arylsulfonamido groups or are substituted by one or more halogen atoms. When using a diazo compound of the formula

N-Ar-N ₉ -X

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in which the substituents are as defined above, the substituents R and R- can be linked to one another to form a cyclic compound, or R and R, can be replaced by a covalent Bond may be linked to Ar, but it is not desirable to include sulfo groups in one of the substituents R, R, and Ar to have as a substituent.

Suitable examples of such compounds are those given above general formula are:

p-Diazo-diphenylamine-p ~ toluene-sulfonate, 4-Diazo-1-naphthol-5-toluene-sulfonate, 4-Diazo-4 * -methoxy-phenylamine-hexafluorophosphate and diazo compounds, e.g. 4- (N-benzyl-N-ethyl) -amino-aniline, 4- (N-2,6-dichlorobeiizyl) -aminoaniline, 4- (N-cyclohexyl) -aminoaniline, 4-Amino-2j5,4 ** tribromodiphenylamine, 4-Amino-2 ', 4', ö'-trichlor «· diphenylamine, 4-amino-2- [N- (2,5-diethoxyphenyl) -sulfamide] -diphetiylamine, 4-amino-3, 6-dimethoxydiphenylamine-2'-carboxylic acid, 1-amino-2,5-di-n-propoxy-4'-methyldiphenyl sulfide, N- (2,6-dichlorobenzyl) -3-aminocarbazole-4- (N-2,3,4,6-tetrachlorobenzyl) -aminoaniline, 4- (N-2,6-dichlorobenzyl-N-ethyl) -amino ~ 2,5-diethoxyaniline and 4-amino · 2,5,4'-triethoxydiphenyl ether.

The condensation products of the above compounds and formaldehyde are preferred. Other examples of diazo compounds are p-quinonediazide compounds, as described, for example, by J. Kosar in "Light-Sensitive Systems: Chemistry and Application of Nonsilver Halide Photographic Processes", pages 336 to 341 (1965). These include, for example, Benzoquinone- (1,4) -diazide (4) -2-sulfonic acid-ß-naphthyiamide, N- (4 ^I -Hethylbanzolsulfonyl) imino-2,5-diethoxybenzoquinone (1,4) diazide-4, the condensate ion product of 2-amino «5" hydroxynaphthalene-7 "sulfanic acid, with

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Naphthoquinone (1,4) diazide (4) -2-sulfochloride, the condensation product of the bisamide of benzoquinone (1,4) diazide (4) -2-carboxylic acid and 4,4'-diamino-dipheny1-2,2'-disulfonic acid , 4,4 * rBis (naphthoch? NXl ", 4 ' ^t ) diazid (4 ^ll ) -2 ^II - (sulfonylamino) diphenyl-2.2 ^l -disulfonic acid, 2.2 ^l -Bis- (naphthoquinone (r ^i, 4 ") diazide (4 ^II) 2" - (sulfonylaraino) diphenyl-4,4-disulfonic acid *, the condensation product of Ν, Ν ¹ -bis (5-hydroxy-7-sulfonic acid ~ naphthyl (2) urea with naphthoquinone (1,4) diazide (4) -2-sulfonic acid and the like.

Shellac has long been known as a natural resin that is deposited by insects. Shellac has a molecular weight of about 1000 to 3000 and has carboxyl, hydroxyl groups and minor amounts of aldehyde groups in the molecule. Shellac, which is soluble in both alcohol solvents and alkali, hardens when heated to a relatively low temperature and provides an excellent surface gloss with mechanical strength and abrasion resistance. When a photosensitive layer containing shellac and a diazo compound is exposed to actinic light, the exposed parts are made insoluble. This mechanism is still unclear, but it differs significantly from that of the other resins, which are generally known to undergo a considerable change even with little exposure, such as coumarone resins, epoxy resins, phenolic resins, xylene resins, melamine resins, cellulose acetate, Cellulose nitrate, polyvinyl acetate, butyral resins, formal resins and the like. Since shellac is a maturing resin, different degrees of purity are obtained depending on the degree of purification, however, apart from the particularly impure ones (e.g. Scheliack species with a pH of above 7), an excellent picture is obtained. When carrying out the invention, the ratio of shellac to diazo compound is set to a value between about 20 and about 0.2, preferably between ?!

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about 10 and about 2 parts by weight of shellac per part by weight of Diazo · » connection discontinued. In addition, other resins can be used in a ratio of less than 0.3 parts by weight per part by weight Shellac can be incorporated.

Examples of such other resins are polymers which are miscible with shellac, such as epoxy resins, urea-formaldehyde resins, Xylene resins ("Daiyuki Kagaku, Volume 23, Gousekoubunshi Kagoubutsu IT", published 1958 by Asakura Book Company (Japan), pages 363-370), polystyrenes, polymethacrylates, polyacrylates, polyvinyl acetates, styrene / maleic anhydride copolymers, vinyl acetate / maleic anhydride copolymers, Polyamide resins and the like. Also can be used to improve the quality desired tenf al Is dyes, fillers and the like are added will.

The photosensitive composition is applied to the surface of a suitable Carrier, for example on paper, plastic or metal (particularly preferred metals are aluminum, copper, zinc, magnesium and iron) j applied to make a printing material. The amount of diazo composition can be within the range of about 0.5 to about 5, preferably from about 0.5 to about 2 g / mn. The surface of the carrier is previously known per se. Art and treated wisely. For example, as described in U.S. Patent 2,714,066, the surface of aluminum is treated with an aqueous Solution of trisodium phosphate degreased, treated with nitric acid and then treated with sodium silicate to finish the surface to make it hydrophilic. Through these treatments the metal surface is deactivated, causing deterioration during the Storage is prevented because any decomposition of the diazo light-sensitive material is inhibited; will, and the surface of the pj.atte is against the oxyda-

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tive contamination protected.

If a printing material according to the invention is replaced by a transparent When exposed to negative light, the exposed part changes and there is a difference in the degree of swelling between the exposed part and the non-exposed part. E.g. will the printing plate according to the invention for 30 minutes in a 1 volume part Containing isopropyl alcohol and 4 parts by volume of water Solution immersed, then the surface of the support is covered with medicated cotton or a sponge rubbed, removing the surface in the parts not hit by actinic light is exposed. Although the mechanism causing the swelling of the photosensitive layer in the struck by the active light Districts is inhibited, not exactly known, it is assumed that the mechanism is due to the crosslinking of shellac, which occurs during the photolysis of the diazo resin radicals formed or due to mere molecular interaction caused by recombinations between the diazo resin.

The invention is illustrated in more detail by the following examples, without, however, being restricted thereto.

example 1

20 parts by weight of shellac and 3 parts by weight of one by condensation of p ~ diazodiphenylamine p ~ toluenesulfonate and formaldehyde Diazo resin was dissolved in 30 parts by weight of dimethylformamide to prepare a solution of the diazo resin. on the other hand an aluminum plate, hereinafter referred to as 2S, was immersed in a 10% aqueous Tr inatr iunipho sphat Io solution of for 3 minutes Immersed at 80 C to degrease them and washed with water. Then the plate was treated with a 70% nitric acid solution and washed with water. The plate was then 3 minutes

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immersed in a 0.2% aqueous zirconium potassium fluoride solution for a long time, which was kept at 80 C. After washing with water and drying, it became from the above-described diazo resin prepared solution on the surface of the aluminum plate treated as described above in the form of a layer applied. The obtained printing material could be engraved using known methods. For example, it was 2 minutes Printing material exposed for a long time with a 30 ampere carbon arc lamp at a distance of 70 cm in a solution of 20 parts by weight Isopropyl alcohol and 80 parts by weight of water. The surface was then gently rubbed with a medicinal cotton ball, which would cleanly remove only the unexposed portion underneath Exposure of the hydrophilic surface. On the other hand, no removal occurred in the exposed part. Printing could be done in the Way to be carried out that the plate without further treatment or after treatment with a gum arabic solution a press was placed.

Example 2

It became a photosensitive solution of the following Composition applied in the form of a layer to an aluminum plate treated as described in Example 1.

shellac

Xylene resin (condensate of xylene and formaldehyde)

Diazo resin according to Example 1, furfuryl alcohol, methanol

The printing material obtained was with a from 30 Gew ..- part of Methanol, 70 parts by weight of water and 0.5 parts by weight of trisodium phosphate existing developer solution developed. The so received «-nc

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18th Parts by weight 3 Il 3 If 50 Il 300 M.

Printing plate was much better than the plate according to Example 1 and at in terms of the hydrophobic property of the image part clear printed matter was obtained for the first few sheets when the plate was placed on a press.

Example 3

An aluminum plate, the surface of which had been mechanically roughened, was immersed in 0.3% aqueous solution for one minute Zirconium potassium fluoride solution, which was kept at 80 ° C., was added immersed and then coated with a sensitive solution of the following composition:

Shellac '18 parts by weight

4-Diazo-1-naphthol-5-toluolsulfona.t 5 "

Methyl cellosolve 200 "

Furfuryl alcohol 100 "

The printing material exposed through a transparent negative film was developed with a 5% aqueous trisodium phosphate solution. After washing with water, the non-image part became made the plate hydrophilic. The plate was placed on a press without further treatment or it was after rubbing a tincture (hydrophobic color) into the image part using the same substance with a gum arabic solution treated.

Example 4

Shellac 10 parts by weight

Polyvinyl acetate 1 "

Condensate of 4-diazo «4 ~ mcthcxyphc-nylamiii- ·

hoxaf luorphospliat and formaldehyde 3 "

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Methylene blue 0.3 part by weight

Methanol 200 "

Furfuryl alcohol 50 "

The above sensitive composition was applied to an aluminum plate which had been anodized and the plate was dried at 100 ° C. for 1 minute. The received media was exposed for engraving through negative film for two minutes with a 30 ampere carbon arc lamp, 10 seconds long developed in a solution containing 10 parts by weight of methanol, 80 parts by weight of water and 1 part by weight of sodium hydroxide and to selectively remove the unexposed part with rubbed on a soft cloth.

In all of the above Examples 1 to 4, it was impossible to distinguish between the 100th hard copy and the 50,000th hard copy that was obtained when using the plate according to the invention to distinguish with regard to the reproducibility of the copy negative. When developing a plate with an ordinary developing varnish, there is sometimes four times the difference in terms the durability between a panel that has been surface treated by a skilled person, and a panel that has been surface treated by an inexperienced consumer. In addition, the halftone dots (halftone dots) often broken in the dark parts when a photographic printing plate is surface treated by an inexperienced consumer will. On the other hand, the quality of the photographic printing plate made from the printing material according to the invention is by no means worse than that of a conventional plate, even if the plate is surface-finished by an inexperienced user

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has been treated. In addition, according to the invention, an average Durability can be achieved. In addition, the present invention can stabilize the Durability (durability) and a simplification of the development process can be achieved.

The printing plates according to the invention have an extremely long shelf life on. If, for example, the printing material according to the invention that had been wrapped with a Kraft paper and on that a 100 µ polyethylene film had been laid, opened and engraved after one year of storage, it was found that that printing material according to the invention had the same print quality as the printing material immediately after manufacture. On the other hand it was found to be carrying a photosensitive composition containing a soluble nylon and a diazo compound Printing material was difficult to develop 5 days after manufacture and it was found to be impossible to use it for 10 days to develop after manufacture.

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Claims (13)

22118U Claims ι IJ Photosensitive composition for presensitized printing plates, characterized in that it contains a photosensitive diazo compound and shellac. 2. Photosensitive composition according to claim 1, characterized in that that it is a compound as a photosensitive diazo compound from the group (1) of the diazonium salts of the general formula: RY-Ar-N ₂ -X
where mean: X is an equivalent of an anion of an acid, Ar is an aromatic radical, R is an aryl, aralkyl, higher alkyl or aroyl radical and Y 0, S, NH or NR, where R _{1 is} an alkyl, aralkyl or arylalkyl group, (2) the condensates of (1) with formaldehyde and (3) the p-quinonediazide compounds. 3. LichtsenstLche mass according to claim 1, characterized in that that it is a compound selected from the group as a photosensitive diazo compound (A) the diazo compounds from the group p-diazo-diphenylamine p-toluenesulfonate, A-diazo-1-naphthol-S-toluenesulfonate, 4-diazo-4'-methoxyphenylamine-hexafluorophosphate, the diazo compounds of 4- (N-benzyl- N-ethyl) -aminoaniline, 4 ~ (N-2,6 ~ dichlorobenzyl) -aminoaniline, 4- (N ~ cyclohexyl) -aminoaniline, 4-amino-2,5,4 ^l -tribromodiphenylamine, 4-amino-2- [N- (2,5-diethoxyphenyl) -sulfamido-diphenylamine, 4-amino-3,6-dimethoxy-diphenylamine-2 ^f -carboxylic acid, 1-amino-2,5-di-n-propoxy-4'-methyl-diphenyl sulfide , N- (2,6-dichloro- 209840/071 1 benzyl) -3-aminocarbazole, 4- (N-2,3,4,6-tetrachlorobenzyl) aTniroaniline, 4- (N-2,6-dichlorobenzyl-N-ethyl) -amino-2,5-diethoxyaniline, 4-Amino-2,5-4'triäthoxydiphenylather, (b) the condensation products of the above diazo compounds (a) with formaldehyde and (C) the compounds from the group of benzoquinone (1,4) diazide (4) -2-sulfonic acid-ß-naphthylamide, N- (4'-methylbenzosulfonyl) imino-2,5-diethoxybenzoquinone (1,4) diazid-4 , the condensation product of 2-amino ~ 5-hydroxynaphthali.n-7-sulfonic acid with naphthoquinone- (1,4) -diazide (4) -2-sulfochloride, the condensation product of the bisamide of benzoquinone (1,4) diazide (4) -2-carboxylic acid and 4,4'-diaminodipheny1-2,2'-disulfonic acid, 4,4 * -bis (naphthoquinone (1 ", 4") · diazide (4 ") -2" - (sulfonylamino) diphenyl-2 , 2 * -disulfonic acid, 2,2 '»bis (naphthoquinone ( ^ll , 4 ^ll ) diazide (4") - 2 "- (sulfonylamino) diphenyl-4,4" -disulfonic acid and the condensation product of N, N'- Contains bis- (5-hydroxy ~ 7-sulfonic acid naphthyl- {2) urea with naphthoquinone * · (1,4) diazide (4) -2-sulfonic acid. 4. Photosensitive composition according to claim 1, characterized in that that the ratio of shellac to diazo compound is within the range of about 20 to about 0.2: 1 parts by weight. 5. Photosensitive composition according to claim 4, characterized in that that the ratio of shellac to diazo compound is within the range of about 10 to about 2 parts by weight. 6. Photosensitive composition according to claim 1, characterized in that that it contains another resin in addition to the shellac, which in an amount of not more than 0.3 parts by weight per part by weight Shellac is too ge ε el-st. 20984Ö / U717 7. Photosensitive composition according to claim 6, characterized in that that they are another resin from the group of epoxy resins, urea-formaldehyde resins, xylene resins, polystyrenes, polymethacrylates, Polyacrylates, polyvinyl acetates, styrene / maleic anhydride copolymers, Contains vinyl acetate / maleic anhydride copolymers and polyamide resins. 8. Photosensitive printing material, characterized in that it consists of a support and at least one layer of the photosensitive Composition according to claim 1 consists. 9. Photosensitive printing material according to claim 8, characterized in that that the carrier is made of paper, plastic or metal. 10. Photosensitive printing material according to claim 9, characterized in that that the carrier consists of metal and that aluminum, copper, zinc, magnesium or iron is used as the metal. 11. Photosensitive printing material according to claim 8, characterized in that that it is a light-sensitive diazo compound from the group (1) of the diazonium salts of the general formula: Φ
N-Ar- N ₀ where mean: X is an equivalent of an anion of an acid, Ar is an aromatic radical from the group phenylene and by AIk) -I, alkoxy, aroxy, arylsulfamido or halogen substituents tem phenylon, R is aryl, alkyl or substituted by alkoxy, halogen and carboxy! Aryl, 20984 0/0717 R _{1 is} hydrogen or alkyl, (2) the condensates of the compounds under (1) with formaldehyde and (3) the p-quinonediazide compounds. 12. Photosensitive printing material according to claim 8, characterized in that draws that the photosensitive composition in an amount of 2 about 0.5 to about 5 g / m 2 is applied to the carrier. 13. Photosensitive printing material according to claim 12, characterized in that that it is the photosensitive mass in a lot 2 contains from about 0.5 to about 2 g / m 2. 209840/0717 ORlGIhSAL INSPECTED