DE1813447A1 - Photosensitive material for the production of half-tone printing forms, process for its production and for the production of the printing form - Google Patents

Description

KALLE AKTIENGESELLSCHAFT Our sign day sheet

K 1863 FP-Dr.P.-is November 25, 1968

description
to register the

KALLE AKTIENGESELLSCHAFT Wiesbaden-Biebric-h

for a patent
concerning

Photosensitive material for the production of halftones printed printing forms, to processes for its preparation un d for the manufacture of the printing form Se ttings

The invention relates to a light-sensitive material for the production of a printing form that prints halftones, which consists of a copy layer carrier and a copy layer located thereon. The invention relates to further a method for producing the light-sensitive material and a method for producing a printing form.

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Photosensitive materials that are used for the production of printing forms have been known for a long time. They consist of a copy layer carrier and a light-sensitive copy layer on it. For the production of printing plates · these materials with the interposition of a template, which dim su printed font or image patterns are equivalent, exposed and developed, the exposed emulsion. If you want to print an image reproducing halftones, you also place a grid between the light source and the copy layer during exposure, in addition to the original. The known copier materials also include those that can be stored for several weeks or months before they are processed into the printing form. The long durability of your copy layer is mainly due to the use of a suitable photosensitive compound. So one knows material in whose copying layer a diazo compound is contained as a light-sensitive compound .

It is also known that certain photosensitive materials which contain a diazo compound in their copying layer are suitable for the production of printing forms printing halftones without the need for one

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needs to use a grid for exposure. The known materials that the manufacture does not halftone halftones enable printing forms to give a print image that has a positive pattern when Exposing the original prints used.

It was assumed that only those copier layers whose light-sensitive copier layer is very thin are usable for the production of printed images that print rasterless halftones. One also knows copier material which reproduces halftones without a grid and which, in addition to a nitro compound, contains 20% resin, based on the weight of the nitro compound, in the copier layer. However, the resin was not added with the intention of increasing the thickness of the copying layer; rather, the resin-containing copying layers were made particularly thin, namely from solutions which contained only 1.2% by weight of solids.

As a result of their low layer thickness, the well-known, for the production of halftone halftones are used printing printing forms suitable materials when printing relatively quickly, so that with it

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The print run that can be produced is correspondingly low. The tonal value gradation that can be achieved with them is also not possible large enough that there is no desire for improvement.

The object of the invention is to overcome the above-mentioned disadvantages of the known material and a to provide better halftone reproductive material. Further tasks consist of specify a process that will be used to manufacture the new material, and specify a process that will be used to The production of halftone printing forms without halftones is used.

To achieve the first-mentioned problem, the starting point is the known photosensitive copying material for the production of a printing form which prints halftones and which consists of a copier layer support and a photosensitive copier layer thereon which contains at least one photosensitive diazo compound and resin. However, the copying material according to the invention has a copying layer which is at least 0.4 microns (0.0004 mm) thick and contains 2.5 to 100 % resin based on the weight of the diazo compound contained in inr.

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ORIGINAL INSPECTED KALLE AKTIENGESELLSCHAFT Our sign day sheet

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The light-sensitive diazo compound contained in the copying layer of the material is preferably one Quinonediazide compound. If an original is to be used for exposing the copy layer, which is a positive of the pattern to be printed, the photosensitive quinonediazide compound may, for example, be Amide or an ester of an o-naphthoquinonediazide sulfonic acid be. If a template is to be used that represents a negative of the pattern to be printed, the light-sensitive Quinonediazide compound can be, for example, a p-iminobenzoquinonediazide compound.

The copy layer contains resin, for example wovolak, novolak modified with chloroacetic acid, resole, Polyurethane resin, polyvinyl chloride, cellulose acetate, alkyd resin, maleinate resin, epoxy resin, copolymers from styrene and unsaturated carboxylic acid, or polyacrylic acid resin. With regard to the quality of the tonal value gradations, the resin content should be as low as possible, In view of the print run that can be achieved, a somewhat higher resin content is desirable. Should the tonal value gradation not be significantly affected by the resin content of the copy layer, but the resin content

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nevertheless cause a noticeable increase in the print run, then preferably resin contents between 2.5 and 25 %, based on the weight of the diazo compound contained in the copying layer, come into consideration.

According to the invention, the copying layer of the material is at least 0.4 microns thick. Copy layer thicknesses of 0.4 microns to about 1.4 microns are preferred for material that is used to make a letterpress form using the exposed and developed copy layer as an etch resist. Copy layer thicknesses which are preferably of the same size also have copy material which must be exposed under a negative original in order to obtain a positive print image. Copy material, which is to be exposed under a positive original and is used for the production of a planographic printing plate, preferably has a copy layer of at least 0.6 microns thick. The thicker the copy layer of a copy material, the longer the exposure times required for its use.

Therefore, for practical use, copy materials with layer thicknesses of more than 3.0 microns are used not considered.

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Copy layers with a minimum thickness of 0.4 microns are obtained in a single application, for example by means of a plate spinner or an application roller and doctor blade, if coating solutions are used which contain at least 1.9% by weight of diazo compound and sufficient resin for the content of the solution of the diazo compound and resin together is at least 2.1 % by weight .

The use of such solutions in the production of the copy material leads to the solution of the above-mentioned second problem. This is based on the known method for producing a photosensitive copying material for the production of a printing form printing halftones, in which a solution containing a diazo compound and resin is applied to a copy layer support and dried, and the method is characterized in that one Applies solution which contains at least 1.9% by weight diazo compound and so much resin that the content of the solution of diazo compound and resin is at least 2.1 % . For the production of copy material which is to be exposed through a positive original, one preferably wears one on the copy layer support

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Solution containing at least 2.2 wt -.% Of an o-naphthoquinonediazide compound and, based on its weight, 2.5 to 100% contains resin.

The quality of the halftone reproduction of the copy material according to the invention also depends to a certain extent on the solvent used in its manufacture. What was found is the quality of the copy material The more polar the solvent used in its manufacture, the better. The best Copy material was obtained when dimethylformamide was used as a solvent for its preparation. the next best results were obtained with dimethyl sulfoxide, 2 »2,3j3-tetrafluoropropanol or 2,2,3,3,4,4,5,5-octafluoropentanol obtain. The use of the solvents mentioned in the production of the copy material is a further subject of the invention.

The above-described photosensitive copying materials according to the invention are for manufacture determined by gridless half-print forms. Her. Use for the production of printing forms with exposure

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through a halftone original, without using a grid, represents the solution to the above third task.

A light-sensitive copying material according to the invention yields, after raster-free exposure through a halftone and developing a print image, the value gradation in the sound M or better in the achievable print run or both relationships as a known light-sensitive copying material, the pressure-forming for producing gridless halftone printing forms is determined .

Letterpress forms produced according to the invention only reproduce a few halftone gradations. But the material is the first material known to be able to produce letterpress plates reproducing halftones without a screen.

In the examples below, amounts expressed in% relate to weight.

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Examples 1 to k

Brushed aluminum plates were coated with solutions containing a photosensitive o-naphthoquinonediazide compound and novolak by means of a plate spinner, and the layer was dried. In all four examples *, the solution consisted of dimethylformamide, which served as the solvent, a novolak which was the same in all examples and had a melting range of 108 to 118 ° C. and an o-naphthoquinonediazide compound which was the same in all examples. This was the diester of _2,3-J 4 Trihydroxybenzophenons whose hydroxyl groups located at the 3- and 4-positions were esterified with l, 2-Naphthochinön-2-diazide-5-sulfonic acid. The preparation of this compound is known, for example from Austrian patent specification 220 640 (Formula 1).

Table 1 below shows the compositions of the coating solutions. In this, D denotes diazo compound, H resin, FK pest body, H: D denotes amount of resin in %, based on the weight of the diazo compound.

T 4. M A

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KALLE AKTIENGESELLSCHAFT 1813447

K 1863

Table 1

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at
game Composition of
Coating solution
in %
D fc PK 4.1 H: D 1 4 0.1 4.9 2.5 2 4.45 0.45 4.0 10 3 3.2 0.8 5.0 25th 4th 2.5 2.5 100

KSt KSD

Dr-A

3-9 0.75 4000 5000

8 0.84 6000 10000

7-8 0.70 10,000 15,000

6-7 0.83

The photosensitive copying materials obtained were erikeil through a step, the one density increment per step of 0.15, each time exposed in such a way that so much through the wedge step which allows the most light to pass through Light passed through that when the copy material was subsequently developed, only the one exposed through this wedge step Part of the copy layer has been completely removed from the copy layer support. The exposure times were 0.5 to 1 min.

The planographic printing phones obtained in Examples 1 to 4 reproduced an image of the step wedge during printing, in which the number of wedge steps indicated in the table under KSt could be recognized. It can be seen from Table 1 that up to a content of 25 % resin, based on the

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Weight of the diazo compound, a not very great reduction in the printed wedge steps occurs, but the influence of the resin content at 100 % is already considerable.

In column J of Table 1, the respective copier layer thicknesses are given in microns under KSD.

The planographic printing plates obtained in Examples 1 to 3 were used for printing in offset printing machines until sagging phenomena could be seen in the prints obtained. The print run achieved (Dr-A) is entered in table 1 in columns 8 and 9, with column 8, under ng, given print runs that were obtained with printing forms that were not exposed to any temperature above 100 ° C. after development were, whereas pressure conditions are indicated in column 9, under g, obtained with compression molding, the printed images were cured by heating at about I5O ⁰ C after the development. It can be seen that in particular a resin content of 10 to 25 % , based on the weight of the diazo compound, is a considerable increase

T 4. 68 A

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of the achievable edition with only a minor Reduction in the quality of the reproduction of the semitones is associated. The halftones are made by the printing forms Excellent reproduction up to the last print.

Examples 5 to 7

Examples 1 to 3 above were repeated except that the o-quinonediazide compound used was the 1,2-naphthoquinone-2-diazide-4-sulfonic acid ester of p-cumylphenol. This connection is from the French patent 1,533,554 known.

The results obtained show the influence of the resin content on the performance of the planographic printing plates obtained in a manner similar to the results obtained in Examples 1 and 3.

Examples 8 to 16

In the manner described in Example 1 above, planographic printing plates were produced, but each time a different resin was used instead of the novolak used in Example 1 above. The following table shows the types of resin used and the number of wedge steps printed in a recognizable manner by the planographic printing plates produced,

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Table 2 Resin type KSt example Polyurethane resin 8th 8th Polyvinyl chloride 8th 9 Cellulose acetate ¹ 9 10 Alkyd resin 9 11th Maleinate resin 10 12th Epoxy resin 8th 13th Styrene maleic acid
Mixed polymer 9 lh Phenolic resin 9 15th Polyacrylic acid 7th 16

It can be seen from the examples that different types of resins can be used to produce copier layers which can be used with good success for the production of screenless printing plates.

Examples 17-22

In the manner described in Example 1 above, planographic printing plates were produced, but instead of the Dimethylformamide used in Example 1 above

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other solvent was used. Table 3 shows the results obtained. Man can see that the use of more polar solvents in terms of the quality of the copy layer their ability to reproduce semitones favorably influenced.

Table 3 solvent KSt example Dimethyl sulfoxide 8th 17th 2,2,3,3-tetrafluoropropanol 8th 18th 2,2,3 »3-tetrafluoropropanol 8th 18th 2,2,3,3,4,4,5,5-octafluoro-
pentanol 8th 19th Acetonitrile 7th 20th Methyl glycol 6th 21 chloroform 6th 22nd

Dimethylformamide

8 - 9

Example 23

In the manner described in Example 2 above, a flat printing plate was produced, but instead of of the brushed aluminum plate, a paper laminated with an aluminum foil on the aluminum surface

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was coated. The plateau form obtained showed 5 to 6 wedge steps in the print image. It showed that copy material whose copy layer is on a relatively smooth surface, brings less favorable results than copy material, whose copy layer is on a roughened surface. But if the result obtained is satisfactory, because the reduction in quality is offset by a simplification of the production of the printing plate.

Example 24

In the manner described in Example 23 above A planographic printing plate was produced, but the copy support used consisted of a plastic film (Polyester film), and a layer of polyvinyl alcohol thereon, which in the presence of Aluminum silicate had been hardened with dimethylol resin. The result obtained corresponds to that in example 3 received.

Example 25

A zinc plate was coated with a solution containing dimethylformamide using a plate spinner

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4ψ

2 % of the o-quinonediazide compound used in Examples 1 to 4, 0.3 % of the novolak used in Examples 1 to 4 and 0.3 % polyvinyl acetate in dissolved form. The layer, which was applied in an air-dry manner with the aid of the plate spinner, was additionally dried by heating at 120 ° C. for 20 seconds.

The copying photosensitive material thus obtained is useful for making a letterpress forme. It was exposed through a step wedge with a carbon arc lamp for 1.5 minutes without using a grid. The copying layer was developed by bathing in an aqueous alkaline developer containing a little methyl glycol contained. The plate was dried and etched in one step at 27 ° C with dilute nitric acid Etched in the presence of plank protection for 4 minutes.

The letterpress form obtained in this way shows 1 to 2 wedge steps in fine-grained etching in its print image.

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Example 26

An aluminum plate with a brushed surface is used

on this with the help of a plate spinner with a

Solution coated in dimethylformamide 1.9 %

1-L4'-methylbenzenesulfonylimino] -benzoquinone-4-diazide-

1 contains 2-sulfonic acid (2 ", 5" -dimethylphenylamide) and 0.2 % novolak with a melting range of 108 to 118 ° C, and air-dried at room temperature. The mentioned iminobenzoquinonediazide compound is described in Example 1 of German Patent 1,104,824,

The light-sensitive copying material thus obtained was passed through a step wedge as in the previous examples exposed with an arc lamp, developed with an aqueous alkaline developer and with printing ink colored. The print image of the planographic printing plate thus obtained showed 5 to 6 wedge steps, the one negative Pattern of the wedge.

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Claims (1)

KALLE AKTIENGESELLSCHAFT K 1863 Our sign day sheet FP-Dr.P.-is 11/25/1968 - Claims 1. Licntempfinaliches copy material for the production of a half-tone printing printing form, which consists of a copy layer support and a photosensitive copy layer located thereon, which contains at least one photosensitive diazo compound and resin, characterized in that the copy layer is at least 0.4 microns thick and, based on the weight of the diazo compound contained in it, 2.5 to 100 % resin. 2. Photosensitive copying material according to claim 1, characterized in that its copying layer contains 2.5 to 25% resin. 3. Photosensitive copying material according to claim or 2 for the production of a planographic printing form, the copying layer of which contains an o-naphthoquinonediazide compound as light-sensitive diazo compound, characterized in that the copying layer is at least 0.6 microns thick. 009826/0908 KALLE AKTIENGESELLSCHAFT Our Zeldien day sheet K 1663 PP-Dr.P.-is 25.11.1968 - 2 <ΞΓ k, A method for producing a photosensitive copying material according to Claim 1, in which a solution which contains a diazo compound and resin is applied to a copying layer support and dried, characterized in that a solution which contains at least 1.9% by weight is applied * Diazo compound and contains as much resin as the diazo compound and resin content of the solution is at least 2.1% by weight. 5. The method according to claim ¹ J, characterized in that a solution is applied which contains at least 2.2% by weight of an o-waphthoquinonediazide compound and, based on its weight, 2, o to 100 % resin. 6. The method according to claim 4 or j> , characterized ge, uato one applies a solution which contains dimethylformamide as a solvent. 7. Use of a photosensitive copying material according to claims 1 to 3 or the photosensitive copying material obtained by the method according to claims k to 6 for the production of a printing form printing halftones with screen-free exposure through a halftone original. 009826/0908 8AD ORtGWAL