CS251286B1 - Negatively working film for photomechanical copying - Google Patents

Abstract

The invention relates to a negative-working film for photomechanical copying of feather, raster or line images. A light-sensitive negative-working layer is applied to a transparent foil substrate, preferably a biaxially oriented polyethylene terephthalate foil, which consists of aromatic azides in combination with natural or synthetic rubbers and which is colored to the desired optical density and color shade with finely dispersed pigments. The film is copied using UV light and developed with a developer composed of aliphatic, aromatic or chlorinated hydrocarbons. The film is used in printing, cartography, electrical engineering, etc.

Description

The invention relates to a negative working film for photomechanical copying of a paired, raster or line image.

These materials are used in the field of printing, cartography, electrical engineering and generally wherever there is a reproduction of spring, raster or line images in a contact way from negative to positive and vice versa. So far, the reproduction of these images has been carried out using contact phototechnical films, which, especially in large formats, do not provide sufficient dimensional stability in relation to temperature and humidity outside the air-conditioned spaces. This resulted in dimensional defects in ditches made of film substrates made under different climatic conditions.

The negatively operating photomechanical copying films of the present invention consist of a film backing and a photosensitive negatively working pigmented photomechanical copying layer consisting of aromatic azides in conjunction with natural or artificial rubbers and finely dispersed pigments to color the layer to the desired optical density and hue.

The backing is a polyester or polyolefinic film, preferably a polyethylene terephthalate biaxially oriented film having a transparency of at least 65%. The light-sensitive negative pigmented layer consists of 0.1 to 30% ethylene glycol ester with p-azidicinnamic acid or the condensation product of 4-azidobenzaldehyde with ketones, preferably cyclohexanone or heterocyclic 6-azido-2- [4-azidostyryl] benzimidazole from 30 to 98% copolymers of 1,3-butadiene with styrene or vinyltoluene or p-chlorostyrene or synthetic or naturally modified cycligacl modified polyisoprene in acid medium and from 19 to 40% of finely dispersed pigments, preferably verses.

Negative copying films for photomechanical copying replace high-slope phototechnical contact films and have the advantage of better dimensional stability, silver wiping and processing options outside the darkroom.

With a maximum UV emission light source, films are contacted by contact with a negative (positive) of high optical densities (> 1.5 ° D). Illumination in illuminated places produces a cross-linked photopolymer / photoresist film which is insoluble in the original solvents of the photoconductive layer or developer. At the same time, the optical density of the image increases by the yellowish coloration of the crosslinked polymer.

The developer of the copying film is technical gasoline, solvent naphtha, white spirit, carbon tetrachloride, trichlorethylene and the like aliphatic or chlorinated aliphatic solvents or mixtures thereof and emulsions.

The light-sensitive layer is prepared by dispersing light-bright pigments, fillers and a light-sensitive solution. Preferably, a dry layer of 2 to 10 µm, preferably 8 µm, is applied to the transparent film by dipping, spraying, rolling or pouring in the thickness of the dry film. The films are dried at elevated temperature preferably in a counter-current tunnel oven.

Example 1

On the polyethylene terephthalate biaxially oriented film of thickness 125 µm, a dispersion of a photosensitive layer is deposited by a method of dipping, which is dried in a tunnel at 60 ° C.

Composition of the coating dispersion:

mineral oil low viscous 1 g ethylene glycol ester with p-ascinnamic acid 2 g copolymer 1,3 butadiene-p-chloroethylene 10 g xylene 38 g toluene 4.5 g

Versal blue A 2.5 g

Versal yellow 0 <1.5 g

Versal red R, g

Dispersions Dored toluene, so that the dried layer has a thickness of 6-8 _/ um.

Example 2

On a polypropylene film of 50 Pa thickness, a dispersion of the photosensitive mass is applied by means of a rod of age, which dries after passing through the drying tunnel at a temperature of up to 50 ° C.

Composition of the coating dispersion:

condensation product of p-azidobenzaldehyde with cyclohexanone / 2,6-bia [N-azidobenzylidene] -cyclohexanone / 2 g copolymer of 1,3-butadiene with vinyltoluene / mixture of isomers / 8 g xylene 40 g toluene 43 g

Versal red R 3 g

Versal blue A 3 g

Versal yellow G 1 g

The dispersion is adjusted with toluene so that the coating layer in the dry state is 6 to 8 µ sup.

Example 3

Sheet foil can be prepared in a similar way. For example, the polyethylene film may be coated either by dipping or wiping with a stick. However, it is advisable to pre-treat the film surface by passing through the root discharge,

Composition of the coating dispersion:

Ethylene glycol ester with p-ezino-cinnamic acid 1 g natural rubber cyclized 9 g xylene 40 g toluene 44 g low viscosity mineral oil 1 g

Versal blue A 2.5 g

Versal red R 1.5 g

Versal yellow O 1 g z

After free drying (with adjusted filters - yellow filters in windows and fluorescent lamps) it is possible to copy immediately to transparencies.

Copying is performed in the illuminated pneumatic frame by a source giving a maximum emission of about 360 mm. Development is carried out by developer, spraying against the foil surface.

Reduce developer quick drying:

technical petrol toluene «

Example 4

A coating dispersion having the following composition is applied and dried on a polyethylene terephthalate film in the manner described in Example 1:

6-azido-2- [4-azidostyryl] benzimidazole 1,3-butadiene copolymer with styrene xylene toluene

Versal blue

Versal red R

8 8g 40g 45g

1.95 g 3.25 g

Example 5

On the polyethylene terephthalate film as in Example 1, a coating dispersion consisting of:

condensation product of p-azidobenzaldehyde with acetone (4,4'-diasidodibenzilideneacetone) tg natural rubber modified by cyclization in acidic environment 9 g xylene 40 g toluene 45 g

Versal blue A 2 g

Versal red R 3 g

Example 6

On the polyethylene terephthalate film as in Example 1, a coating dispersion comprising:

4,4'-diazidobenzophenone 2 g synthetic polyispprene modified by cyclization in acid medium 10 g xylene 40 g toluene 43 g

Versal blue A 1 g

Versal Yellow O 4 g

In all examples, the pigments in the coating dispersion are dispersed by wet grinding to a fineness of individual particles of up to 5 µm in diameter.

Claims (3)

M ί Ϊ D MI I OF THE INVENTION Negative-working photomechanical copying film, consisting of t-film backings and photoresist negatively-working pigmented photomechanical copying layers, consisting of aromatic azides in conjunction with natural or artificial rubbers and finely dispersed pigments, by which the layer is colored to the required optical density and color shade, in that the backing is a polyester or polyolefinic film, preferably a polyethylene terephthalate biaxially oriented film having a transparency of at least 56%, and the photosensitive negative working peigmented layer consists of 0.1 to 30% ethylene glycol ester with p-azidicinnamic acid or the same amount of condensation product 4-azidobenzaldehyde with ketones, preferably cyclohexanone, or an equal amount of heterocyclic 6-ezido-2- [β-azidostyryl] benzimidazole, from 30 to 98% of 1,3 copolymers, 1.3 butadiene with styrene or vinyl body or p-chlorostyrene or an equal amount, an amount of synthetic or naturally modified cyclisacl polyisoprene in an acidic medium and of finely dispersed pigments in an amount of 2.9 to 40% by weight of the dry layer, preferably versal pigments. 2. A film according to claim 1, characterized in that the light-sensitive negative pigmented layer is uniformly applied to the transparent substrate in a thickness of 2 to 10 [mu] m, preferably 6 to 8 [mu] m of dry layer. 3. Negative film according to claims 1 and 2, characterized in that the pigments are finely dispersed in the layer by wet grinding up to a particle diameter of 10 [mu] m, preferably below 5 [mu] m.