DE1671626C3 - Photosensitive copying material for the production of offset printing plates - Google Patents

Description

The invention relates to a photosensitive copying material for the production of offset printing plates with a layer support made of aluminum and a light-sensitive copying layer made of an acid-hardenable one Resin and a photosensitive halogenated hydrocarbon.

The use of such copy materials is e.g. B. from Belgian patent specification 6 70 886 known in the copying layers of an acid-curable resin and a photosensitive halogenated hydrocarbon are described. Such layers make good offset printing plates when used as Supports anodized aluminum or paper with a hydrophilic primer used.

On oxide-free or low-oxide aluminum, especially on aluminum roughened by brushing, however, the cured resin layer does not adhere very firmly, so that such printing plates do not produce high Can achieve editions.

However, it would be desirable to use anodized instead of the more difficult to manufacture and therefore more expensive To be able to use aluminum carriers made of oxide-free or low-oxide aluminum. Such Carrier materials are made by mechanical roughening, e.g. B. by brushing, or by another simple pretreatment obtained from normal rolled aluminum.

The object of the invention is to improve the adhesion of exposed copying layers made from acid-curable resins and light-sensitive halogenated hydrocarbons on low-oxide or low-oxide aluminum as a support to improve.

The invention is based on a photosensitive copier material for the production of offset printing plates with a photosensitive copying layer made of an acid curable resin and a photosensitive Halocarbon and with an aluminum film support. dei on his the Kopimchichl facing side is oxide-free or low-oxide.

The material according to the invention is characterized in that an intermediate layer from 1 to 10 nm thick is wiped out between the substrate and the copier layer one by lormaklchvc! hardened high molecular weight, originally water-soluble binder is located.

The hardening of the water-soluble binder is achieved with | 'oniiakleh \ il. b / w. mil I > iriii.iklchytt splitting off Links /. fi. Paraforinaldohul or hexamethylenetetramine, expediently carried out with heating. It can be carried out by adding acidic compounds be accelerated.

Suitable high molecular weight water-soluble binders are, for. B. polyvinyl alcohol, hydroxyethyl cellulose, Polyacrylamide and dextrin. Particularly good results are obtained with polyvinyl alcohol. The ones in the trade types with K values between 30 and 90 (viscosity determination according to Fikentscher) and with

to different acetyl group content are for the Well suited for the present purpose.

To produce the adhesive layers, the high molecular weight binder is dissolved in water and the Formaldehyde and, if necessary, alcohol for better wetting and brings the solution in known Way, e.g. B. by spinning or GiWJen on oxide-free or low-oxide aluminum. The concentration of the solution is adjusted so that one after drying, layer thicknesses of 1 - lOnm,

M contains at least monomolecular layers. The coated one is then advantageously heated Layer support, e.g. B. in a drying cabinet or under an IR radiator until the layer is sufficient hardened, d. H. has become sparingly soluble in water. The light-sensitive plate is placed on the prepared plate Copy layer applied in a known manner.

Practically all acid-curable resins can be used as copying layers for the material according to the invention used in connection with light-sensitive halocarbons, their light-decomposition products harden these resins. Examples of such layers are given in the Belgian patent 6 70 886.

The use of adhesive layers according to the invention in connection with copying layers is particularly advantageous, the acid-curable aldehyde-amine condensates, e.g. B. condensates from formaldehyde and urea or melamine, because the adhesion of such layers is improved particularly well.

The intermediate layer made of the hardened high molecular weight binders increases the adhesion of the exposed and developed copying layer on the substrate is improved to such an extent that the one achievable therewith Height of the print run compared to printing plates that

* 5 does not contain the intermediate layer according to the invention, is increased to a multiple.

In the following examples, aluminum roughened by brushing was always used as the support. as well however, aluminum supports can be used. the one pretreated in another way or have cleaned oxidar.ne or oxide-free surface.

In the examples, the volume unit should be 1 ecm if I g is selected as the unit of weight.

Example I.

10 Voliimteile a 0, l ° / o aqueous solution of acciylgruppenfreiein polyvinyl alcohol having a K WCRi 70 were mixed with 40 parts by volume of a 40% ^l: i> rma | dchydlösung and 50 Volumteilcn ethanol, and the mixture on a brushed aluminum foil spun. The plate was dried for 10 minutes at I) OC and then coated with the following copy solution:

IO parts of a 55 'Vtngi-n butanolisclien Lö

Solution of a curable melamine resin ¹ -

2 parts by weight

I part by weight
0.2 parts by weight

Polyvinyl acetate with an average molecular weight of 1,000,000
Iodoform
Perylene

0.005 parts by weight astrazon red 6 B (C. 1.48 020)
90 parts by volume of toluene

For conversion into a planographic printing plate, the coated foil was successively placed under a film negative Exposed for 15 seconds with a carbon arc lamp at a distance of 65 cm, 30 seconds in one Drying cabinet heated to 150 "C and with isopropanol wiped until the unexposed areas peeled off, and finally the exposed area was exposed Aluminum surface hydrophilized with sodium metasilicate solution The printing plate produced 25,000 halftone prints on a small offset press.

Example 2

An aluminum foil was made! One after the other with the following Coated solutions:

a) Adhesive layer solution:

10 parts by volume of a 0.1% aqueous solution

Solution of polyvinyl alcohol with a K value of 30, containing acetyl groups

10 parts by volume of glycol monomethyl ether

40 volume part 40%? aqueous formaldehyde

solution
Ethanol

340 parts by volume
b) Copy solution:
10 parts by volume

1 part by weight

1 part by weight
0.2 parts by weight
0.005 parts by weight
115 parts by volume

that used in Example 1

Melamine resin solution

Polystyrene with a middle

Molecular weight of 100,000

Iodoform

Perylene

Astrazon red 6 B (C. 1.48 020)

toluene

Before the copying layer was applied, the adhesive layer was heated to 150 ° C. for 10 minutes.

As described in Example 1, the coated film was converted into a planographic printing plate. With the printing plate, 25,000 good halftone prints were obtained on a small offset press.

Example 3

F.inc mix of

10 parts by volume of a 0.1% aqueous solution of polyvinyl alcohol (K value 70, containing acetyl groups)

IO Volumicilen glycol monomethyl ether and
180 volumes of ethanol

was spun on aluminum foil. The film was ^{heated to I 1} JO ¹ C for 10 minutes and then coated with the following copying solution:

10 Volumtoile of those mentioned in Example I.

Mclaminhjrzlosung
Ο.ϊ ("JlM ', iiJiisicile schlapfesies polystyrene

1 weight part
0.2 parts by weight
0.005 parts by weight
120 parts by volume

Iodoform

Perylene

Astrazon red 6 B (C 1.48 020)

toluene

An offset printing plate produced from the coated film as described in Example 1 delivered 45,000 good halftone prints.

Example 4

The following solution was used to pre-coat aluminum:

10 parts by volume

10 parts by volume
80 parts by volume
0.005 parts by weight

an 0.1% aqueous solution of polyvinyl alcohol (K value 30, free of acetyl groups)
Glycol monomethyl ether
Ethanol
Hexamethylenetetramine

The adhesive layer was heated to 150 ° C. for 10 minutes and then with that listed in Example 2 Copy solution overlaid.

With an offset printing plate obtained from the film according to the information in Example 1, 2000 Halftone prints achieved.

Example 5

An aluminum foil was precoated with the following solution:

10 parts by volume of a 0.1% aqueous solution of

high viscosity hydroxyethyl cellulose
10 parts by volume of glycol monomethyl ether
40 parts by volume of ethanol

40 parts by volume of 40% aqueous formaldehyde solution
100 parts by volume of water

The applied layer was ^{warmed to 150 ° C.} for 10 minutes and then the copying solution given in Example 2 was painted over. An offset printing plate made from the coated film provided 10,000 prints.

Example 6

10 parts by volume of a 0.1% aqueous solution of polyacrylamide were mixed with 10 volumes of glycol monomethyl ether, 40 parts by volume of a 40% aqueous formaldehyde solution and 140 parts by volume of ethanol mixed and the mixture spun on an aluminum foil.

The film was heated to 150 ° C for 10 minutes, then coated with the copying solution according to Example 2 and according to the instructions in Example 1 in an offset printing plate convicted.

Wed! 8000 good halftone prints were achieved on the printing plate.

Example 7
The adhesive layer solution consisted of

IO volume of an oil, 1% aqueous dexirinlo-

sung

10 parts by volume of glycol monomethyl ether
10 parts by volume of a 40% strength aqueous formaldehyde

solution
70 parts by volume of ethanol

The coated aluminum foil with the solution wiirile 10 minutes 150 '^"1 C heated and then overcoated with Eihei copying solution to that of

jjspjel I corresponded to, but contained no polyvinyl acetate, after the information in Example 1, the material was transferred to an offset printing plate. 4000 good screen prints could be obtained with the plate.
If the printing plates described in the examples were produced with otherwise the same procedure without using the adhesive layer according to the invention, it was only possible to achieve run lengths of between about 100 and 1000 prints with them.

Claims (2)

Patent claims: 1. Photosensitive copying material for the production of offset printing plates with a photosensitive Copy layer made from an acid-curable resin and a photosensitive halogenated hydrocarbon and with an Aiuminiumschichtträger, which on its facing the copy layer Side is oxide-free or low-oxide, characterized in that there are layers between the substrate and copying layer, an intermediate layer 1 to 10 nm thick made of a formaldehyde-hardened one high molecular weight, originally water-soluble binder is located. 2. copying material according to claim 1, characterized in that the intermediate layer of hardened Polyvinyl alcohol is made.