DE1171263B - Release film for use in the manufacture of gravure forms - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Boarding school Class: G 03 c

Number:
File number:
Registration date:
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German class: 57b-3

P 24389 IX a / 57 b
5th February 1960
May 27, 1964

The invention relates to photographic release films and, more particularly, to dimensionally stable or dimensionally stable films Dry release films for use in the manufacture of gravure forms.

The best-known method for forming an etching base for gravure forms is the so-called Pigment paper process in which a pigmented gelatin layer sensitized by bichromate solution is exposed imagewise. Such a layer is generally drawn up on a paper backing. The exposure hardens the gelatin layer according to the image. The exposed The film is then wetted with water and squeezed onto a printing plate, for example made of copper. By applying hot water to the back of the adhering film softens the gelatin so that the paper backing can be peeled off. The soft unexposed gelatin is then washed off with warm water and leaves on the printing plate a pigmented gelatin relief image, which can then be etched image-like, so the well-known Form rotogravure form. This method has disadvantages because it requires very skillful handling to produce satisfactory printing forms. For example, the exposure must be careful be set, since overexposure hardens the gelatin to a great depth and thereby peeling off the paper backing is made difficult, if not impossible. With an underexposure an insufficient formation of the relief image is achieved. It is still necessary that Sensitize gelatin layer just before use with bichromate solution, so that the consumer and the manufacturer of the pigment paper does not have to carry out this sensitization. With this one Long exposure times are necessary because of the sensitivity of such systems is mainly in the short wavelength region of the spectrum (i.e. 350 to 550 ΐημ). This is one enormous disadvantage, since it is practically impossible to determine the spectral sensitivity with such a Move system. In addition, the poor dimensional accuracy is also a major disadvantage.

To overcome these disadvantages, gelatin-silver halide emulsions have been used which are coated on a permanent hydrophobic film support with a layer of gelatin or other soluble peel-off layer between the emulsion and the support. It has also been suggested to use insoluble, tacky release liners, but these have also been unsatisfactory. Because of dimensional stability, release film has been used in manufacturing
of gravure forms

Applicant:

E. I. du Pont de Nemours and Campany,

Wilmington, Del. (V. St. A.)

Representative:

Dr. rer. nat. J.-D. Mr. v. Uexküll, patent attorney,

Hamburg-Hochkamp, Königgrätzstr. 8th

Named as inventor:

Francis Peter Alles, Westfield, N. J. (V. St. A.)

Claimed priority:

V. St. v. America February 27, 1959

(795 923)

proposed a so-called "temporary" carrier (e.g. a cellulose derivative) with a peel-off layer, a "permanent" carrier (e.g. a cellulose derivative film) and a silver halide emulsion to cover the necessary intermediate anchoring layers.

Although the use of gelatin-silver halide emulsions has considerable advantages over light-sensitive layers of gelatin and bichromate and the peel-off films are extremely advantageous because of the time savings, they have other disadvantages besides those mentioned above. For example, if the film is exposed, developed and squeezed onto the printing plate using conventional photographic processes, considerable skill is required to remove the temporary and permanent support if the subsequent hot water etch is to produce a good quality etch base. These disadvantages are avoided by the release films of the invention. They consist of a flexible, hydrophobic, organic, polymeric film base (a), on the surface of which a thin peel layer φ) made of a mixture of

1. 40 to 80 parts by weight of an n-butyl methacrylate-itaconic acid copolymer with a content of 96 to 99.5 percent by weight n-butyl methacrylate with

409 597/333

2. 60 to 20 parts by weight of a vinylidene chloride hexamethylene adipamide and polyhexamethylene seba mixed polymer which is at least 35 parts by weight camide; Polyester, e.g. B. contains polyethylene terephthalate, poly percent vinylidene chloride, preferably an ethylene terephthalate isophthalate and poly (trans-vinylidene chloride-ethylenically unsaturated ester-p-hexahydroxylene) terephthalate. Itaconic acid copolymer, e.g. B. a vinylidene 5 them from an oriented, highly linear polyalkylene chloride-methacrylate-itaconic acid copolymer, terephthalate, from the polyesterification which these substances in appropriate proportions product of a polymethylene glycol with 2 to 10 carbons from 35 to 96 percent by weight, 3.5 to 40 Ge - Material atoms with terephthalic acid, weight percent and 0.5 to 25 weight percent film bases made of orientable polymers and contains, io in particular polyalkylene terephthalate ^ can be put in an anchoring layer (c) of a water by pouring the polymer and then pouring organic colloids such as gelatin Rear vinylidene chloride copolymer with a content of up to 20 percent by weight of the layer (/) on which one surface of the cast film gelatin weight of water-soluble polyvinyl is applied. The coated film can then be coated with pyrrolidone (which under certain conditions 15 orientates in a known manner and, under heat, solidifies the anchoring and uniformity of the coating and improves it with a water-permeable colloidal layer) and a water-permeable organic sub- layer (g) , like all colloidal silver halide emulsion layers ( e) carries. For example, in German patents 925 032 A thick layer (d) of soluble gelatin can and 1 102 381 is described in more detail. between the anchoring layer (c) and the 20 After the above treatment, the mixture of the emulsion layer (e) will be applied. The side of the support opposite to n-butyl methacrylate — itaconic acid and vinylidene can be drawn onto the opposite mixed polymer layer (/) made of vinylidene chloride and methane with a rear-side chloride — methyl acrylate — itaconic acid and an acrylate / itaconic acid mixed polymer and a gelatin - Dries to obtain the release layer (b) . Lower layer (g) may be overlaid. The use 25 Then the anchoring layer (c) and a vinylidene chloride mixed polymer layer between a thick water-soluble gelatin layer (d) are applied, the polyester film base and a gelatin layer and the film is subjected to further heat as usual in the German patent 925 032 treatment to the stresses described in the. Repeal film, as it is for example in the German

The above stripping layer φ), which is described from a 3 ° patent specification 1 095 514.

Mixture of n-butyl methacrylate-itaconic acid mix- The light-sensitive gelatin-silver halide-

polymeric and vinylidene chloride-unsaturated ester emulsion layer (s) should not contain any hardeners;

Itaconic acid copolymer, can at 50 to the same applies to the thick soluble gelatin

93 ° C and preferably at 54-88 ⁰ C dried lower layer (d), if in addition to the emulsion layer

will. The unsaturated ester can preferably be 35. However, the emulsion layer (s) must after

Methacrylate, but also, for example, another exposure of an object field or image either

Alkyl acrylate and alkyl methacrylate, vinyl chloride or in a hardening developer or in a hardening one

Be acrylonitrile or methacrylonitrile, whereby the bleach bath can be hardened differently, so

the latter as unsaturated esters of hydrogen chloride - that by washing off the unexposed and un-

or hydrocyanic acids. 4 ° cured emulsion a relief image can be formed

The pH of the mixtures of the interpolymer can. In addition, the ratio of gelatin is said to be

dispersions is usually about 2.3 to 2.5; to silver halide being large, with a range of

however, this value is not critical and can be 2 to 5 parts by weight of gelatin to 1 part by weight

a suitable alkali, for example ammonium silver halide, is satisfactory. Anyone can do it

hydroxyd, without harmful side effects on a 45 desired light-sensitive silver halide, e.g. B.

higher range can be set. Silver chloride, silver bromide or silver iodobromide,

The interpolymers can be used in any of desired ways.

known way. For example, when producing etching supports from the photographic films according to the invention, the n-butyl methacrylate-itaconic acid mixed polymer can be produced by emulsion polymerisation using one of the customary processes for producing a persulfate catalyst or an equivalent production of the desired latent image in the catalyst while the vinylidene photosensitive layer is exposed. In the case of chloride-methacrylate-itaconic acid mixed polymer by producing a gravure printing form, the film can be prepared in one emulsion polymerization or by polymerization, for example by means of a gravure screen, (bulk polymerization). 55 appropriate time exposed and then through a halftone-This mixed polymer can be exposed with water and the positive or vice versa. Other two-component conventional halftone types and exposure sequences described above can be mixed in mixed polymer. The dry coating weight of the 60 composed of the mixture raster and the orange or magenta contact raster of the copolymers 1 and 2 in combination with a predominantly yellow light peeling layer (b) can be used, including the usual glass, from 10 to 25 mg / dm ² vary. source as described in U.S. Patent 2,628,903. In general, lower coating weights give. The exposed film can then have a higher peel tension within this range. a known hardening developer, for example according to The film base (a) can be developed from any US Pat be by the Emulsionsz. B. Cellulose acetate, acetate butyrate and propionate surface on a copper or other metal plate and cellulose nitrate; Super polyamides, eg poly pressed and the film backing is peeled off as it is

also described in U.S. Patent 2,650,878. The ratio of the monomeric components of the copolymers in the release layer (b) can vary. In the n-butylmethacrylate-itaconic acid copolymers, the weight fraction of n-butyl methacrylate, 96 to 99.5 ° / o ^un d is preferably 98 to 99 ⁰ I _0, with the balance of course is itaconic acid. In the case of the vinylidene chloride-unsaturated ester itaconic acid copolymer, in general, the

will; in the examples, the photographic films were made essentially to the exclusion of actinic light produced.

Example I.

There was a Polyäthylenterephthalatfilmunterlage (ä) suitable for the process according to German patent 925,032 by pouring the melt on the following quantity ranges and desirable: 10 produced a cast disc and a 4 ° / ₀ aqueous solution of a mixed polymer of polyvinylidene chloride (85) acrylonitrile ( 15) —Itaconic acid (2) coated according to Example II of German Patent 942 313, so that an anchoring layer (/) 15 was formed. The film was stretched first in the transverse direction and then in the longitudinal direction by a stretching process according to German patent specification 925 032 to form a 0.1 mm thick molecularly oriented film base. A gelatin solution of the following composition was spread onto the rear mixed polymer layer (J) 20 to form the gelatin underlayer:

Vinylidene chloride ..
Unsaturated ester
Itaconic acid

Generally

more suitable

Area in

Weight percent

35.0 to 96 3.5 to 40 0.5 to 25

More preferred

Area in

Weight percent

60 to 94 5 to 35 Ibis 5

Benzene, toluene, xylene, dioxane, acetone, turpentine and mixtures of two or more of these solvents as well as other organic solvents can be used to remove the interpolymer peel layer (b) after application.

While the silver halide emulsion layer (e) and the thick soluble gelatin layer (d) are generally colorless, color can be incorporated into either or both of these layers for a variety of reasons. For example, the thick soluble gelatin layer (d), if used, may contain a dye for preventing halation, so that it is unnecessary to provide an antihalation layer on the back of the base.

Various photographic sensitizing agents can be added to the silver halide emulsions, if desired Dyes, e.g. B. cyanine, pseudocyanine, carbocyanine, merocyanine and styryl dyes.

Weight percent

Gelatin 1,000

Thymol 0.015

Cetyl betaine 0.090

Chrome alum 0.020

Colloidal silica

(17 πιμ particle size) 0.90

3 n-NaOH for adjustment

the pH to 6.0. Make up with water to 100,000

sulfate, 294.0 g of inhibitor-free n-butyl methacrylate and 6.0 g of itaconic acid. The air in the flask was displaced with nitrogen and potassium persulfate and 0.60 g in 26.0 ml of water were added. The mixture was stirred under nitrogen and the temperature increased to 50 ° C. After a short exposure time the implementation began (which is characterized by a

An interpolymer blend was prepared as follows: A 1-1 three-necked flask with a Equipped with a stirrer, a nitrogen supply tube, a thermometer and a reflux condenser put the sensitivity to 40 in a hot water bath. In the flask were green or red areas of the visible spectrum to expand 350 ml of distilled water, 12.0 g of sodium laurel.

The novel dry release films of the present invention so produced are reliable and proven

satisfactory results. Their preparation is 45 solution from 1.18 g
simpler and more economical than that of the general sodium metabisulphite
films used in gravure printing, where
of course the superiority of the films, which
Use silver halide emulsions over the

gelatin (temperature rise noticeable in the much earlier processes). The polychromate layers on paper supports recognized merization was continued for 3.3 hours, and which must be. Temperature was kept between 50 and 7O ⁰ C.

Another and salient advantage of the milky-white dispersion was increased to 44.0% Invention is the ease with which the peel-off poly (n-butyl methacrylate-co-itaconic acid, 98: 2) strains 55 lysed are discontinued during manufacture.

can. This is of the utmost importance for the aqueous dispersion of the polyacceptable thus obtained Product which in graphic (n-butyl methacrylate — itaconic acid) (98: 2) became Commercial is to be exploited. a 15 weight percent solids dispersion

Although the novel release liners, as thinned above. It was according to Example I of the German mentioned, in connection with various documents 60 patent specification 942 313 an aqueous dispersion of can be used, they are especially vinylidene chloride — methyl acrylate — itaconic acid with effective when using monomer weight ratios of 85: 15: 2 on orientable polyester films which, as described above, are made out. This aqueous dispersion was also on Polyalkylene terephthalate exist. These make up the 15 weight percent solids diluted. Servings of the important advantage of dimensional stability, which with the above 65 aqueous dispersions were in a Ver

previously known release films was not achievable. The invention is further elucidated by the following examples explained, but not restricted in any way

ratio of 80 percent by weight of n-butyl methacrylate-itaconic acid copolymer 20 percent by weight vinylidene chloride - methyl acrylate - itaconic acid - mixed

7 8

polymer mixed. 1. Bath "A" (3 minutes) was added to the mixture obtained.

4% of the total weight of the solution of 5 g by weight sodium metabisulphite

percent alcohol-water-saponm solution added. The pH of the resulting mixture pyrogallol 5 g

was 2.5. S Anionic wetting agent

The mixture was poured onto the opposite upper (10% aqueous solution) ... 2 ml

The area of the polyethylene terephthalate film was made up to 11 with water

Speed of 12.2 m / min in such a g _{a (} j _(> g ₍₍ n minutes)

Amount drawn up that the dry coating weight

Was 10 mg / dm ² . The resulting coating was 100 g with sodium carbonate (monohydrate)

Dried at 88 ° C and formed the Peel-off Layer®. Anionic wetting agent

A gelatin (10% strength aqueous solution) ... 2 ml

Anchoring layer (c) of the following together- Topped up with water on 11

Settlement applied: percent by weight 2. Washing in water of 2O ⁰ C for the duration of

Gelatin 1,000 ^! Minute.

Thymol 0.010 3. Fixing in a solution of the following compositions

Cetyl betaine ... 0090 setting at 18.3 ° C and for the duration of

_v "., _c . '.'. '"'! '"' '3 minutes:

Colloidal silicon dioxide.

(Particle size 17 ΐημ) 0.090 ²⁰ sodium thiosulphate 200 g

Polyvinylpyrrolidone Boric Acid 15g

(average topped up with water to 11

Molecular weight 40,000) 0.160 4. Washing in water at 20 ° C for the duration of

Chrome alum 0.017 25 10 minutes.

Made up to 100,000 with water. 5. Dry the film.

The film was then heated at 120 ^° C. The film processed in this way was then treated with the

relaxed, as it is in the German patent Emulsion layer down on a gravure printing

1 095 514 is described. Squeezed onto the gelatin anchored copper plate, as it was when it was applied

layer (c) was a gelatin solution of the material used to form the etching base.

applied composition: “. ,,, The pad then became dry from the film

Weight percent, _ .. ^ö , ", .., _r . , _o,. ,.

deducted. The layers adhering to the gelatin

Gelatin 5,500 from the mixture of copolymers 1 and 2 were made

Potassium chloride 0.032 35 removed by solution with methyl ethyl ketone. For this

Saüonin 0 045 were up to a satisfactory distance 1 to

. 'Requires 4 minutes. The one containing the film

Υ ^ ^ζεπη ° ' ¹⁵⁸ copper plate was then placed in a bath for 10 minutes

Ethyl alcohol immersed in 1.820 hot water of 52 ⁰ C to the whole

Thymol 0.010 40 to peel off unexposed, unhardened gelatin and so on

Filled up with water to 100,000 ^a relief of various thicknesses (in direct

Depending on the silver density) from hardened

This gelatin composition was used to educate gelatin to form on the copper. After thorough development of a soluble gelatin layer applied, drying of the gelatin relief image and the generally which had a coating ^{weight of about 50 to 60 mg / dm 2} , 45 in the art usual coverage of the base areas based on the weight of the gelatin. of the copper with asphalt were after gravure printing on the thick, soluble gelatin layer (d) , conventional methods with iron chloride solutions to form the emulsion layer (e) were etched into the copper. emulsion with 25 mol percent silver chloride content

painted. The coating weight of the example emulsion layer obtained was about 60 to 65 mg of silver. Example I was repeated, but now the halide per square decimeter, so that a peel layer (b) with a 15 weight percent layer thickness of about 0.015 mm resulted. Finally, an aqueous solution of a mixture was coated over the gelatin underlayer 8 on the back, which was composed of 70 percent by weight n-butyl methacrylate side of the film and an antihalation layer (Zz) made of itaconic acid mixed polymer and 30 percent by weight of gelatin-chrome alum and "acid magenta Ο"(Rowe's Vinylidene chloride, methyl acrylate, itaconic acid - mixed color index No. 692). polymer. All other process steps in The resulting dried film were in one of the production, exposure, development and on-vacuum printing frame by a conventional 150-line application on the copper plate were identical to Example I grid 8 seconds with a 25-watt tungsten lamp. The peeling of the substrate from the exposed which was 2.45 m away from the grid. the layer consisting of the mixture of the mixed polymers. The film was then exposed behind a step wedge 9 seconds after application was satisfactory and was somewhat exposed to the 15 watt lamp 2.45 m away due to a decrease in the peel tension. The exposed film was then 3 minutes 65 lighter than in Example I. The usual gravure printing in a bath (A) and then for 2 minutes were carried out after peeling off, as described in Example I in a bath (B) of the following composition whereby a satisfactory winding: etched printing plate of good quality was obtained.

Claims (1)

9 10 Hold Example III and see U.S. Patents 2,627,088 Example I was repeated again, wherein and 2,698,235 are described, can in equi- now the peel- off layer (b) from 15 weight-equivalent quantities for those listed in the examples percent aqueous solution of a mixture can be used. The unsaturated esters can Was worn, which from 60 percent by weight 5 ethyl, methyl, propyl or butyl methacrylate or n-butyl methacrylate-itaconic acid mixed polymer and acrylate, vinyl chloride, acrylonitrile or methacrylic 40 percent by weight vinylidene chloride methyl acrylate nitrate. Itaconic acid copolymer. All other claims
conditions and process steps of production, Exposure, development and application to the i ° 1. Release film for use with the Her gravure plate were identical to Example I. The position of intaglio printing forms, which resulted from a peeling of the backing from the film after the flexible hydrophobic organic, polymeric application was satisfactory, and the peeling film backing, a peeling layer, a bracing was somewhat smaller than in Example II Peeling was carried out the usual gravure printing process of organic colloid and an organic colloid described in Example I, with an identical silver halide emulsion layer, since a satisfactorily etched printing plate of good quality is characterized by the fact that the abutment was obtained. Strip layer (b) from a mixture of 40 to Example IV ^ parts by weight of a n-butyl methacrylate 2 ° Itaconic acid copolymers, which are 96 to 99.5 There are Examples I, II and III repeats, per cent by weight n-butyl methacrylate, and wherein the formation of the peel layer (b) the 15ge- 60 to 20 parts by weight of vinylidene chloride runt-percentage is aqueous dispersions of the mixed polymer containing at least 35 weight polymers having a Contains percent vinylidene chloride dry coating weight.
17 mg / dm ^{2 were} applied. In all cases, 25 was 2. The release film according to claim 1, characterized in that the dry release was satisfactory and resulted in the vinylidene chloride having a good quality printing form. The peel-off ethylenically unsaturated esters, especially with tension, decreased in all three films as the coating weight of the stripping layer increased with a lower alkyl acrylate or methacrylate. After the vinyl chloride or acrylonitrile or methacrylonitrile had been stripped off, the usual gravure printing processes such as 3 ° and with itaconic acid in the corresponding proportions described in Example I were carried out and resulted in a satisfactorily etched printing form of good percent or 0 from 35 to 96 percent by weight, 3.5 to 40 percent by weight, 5 to 25 percent by weight mixed quality. . . is polymerized. ö e 1 s ρ 1 e 1 V 3 ^^ fiim _{according to} claim 2, characterized in that Example I was drawn up, with the following exceptions, that the unsaturated ester was methyl acrylate lungen repeated: The peel layer (b) was from is. a 10 weight percent aqueous solution of a 4th release film according to claim 1 to 3, characterized Mixture of 50 percent by weight n-butylmeth- characterized that the organic colloid in acrylate-itaconic acid copolymer and 50% by weight of the anchoring layer (c) and the emulsion percent vinylidene chloride-methyl acrylate-itaconic acid layer (s) is gelatin. Mixed polymer applied. The gelatin anchoring 5. release film according to claim 4, characterized Layer (c) and the gelatin sub-layer (g) were drawn, as was the anchoring layer (c) from a solution that contains the following poly (N-vinyl-2-pyrrolidone) in amounts of 10 to Compositions in percent by weight had: 20 percent by weight, based on the gelatin Trpiatinp η fiRfi ⁴⁵ weight, contains. rr [J '? J "6. A release film according to claims 1 to 5, characterized in that ^{lnvmo1 υ} ' ^υιυ characterized that a thick water-soluble gel C-cetyl betaine 0.090 tin layer (d) between the emulsion layer (e) Colloidal silica and the anchoring layer (c) is arranged. (Average ₅ o 7. release film according to claim 1 to 6, characterized Particle size 17 πιμ) 0.090 characterized in that the peel layer (Z>) 0.07 to Chrome alum 0.017 0.2 mm thick. Made up to 100.0 with water. 8. Release film according to claim 1 to 7, characterized PH value with aqueous NaOH indicated that the film base (α) from adjusted to 6.0 55 a highly polymerized linear polyalkylene terephthalate exists, in which the alkylene The solutions were grouped at a rate containing two to ten methylene groups, of 18.3 m per minute applied to a dry 9. peel-off film according to claim 1 to 8, characterized To give a coating weight of 14 mg / dm ^2. That featured that the back of the film one further conditions during drying, exposure and 60 back mixed polymer layer (J) of a vinyl Tests were the same as in Example I. The idene chloride mixed polymer, which at least Peeling off the backing from the film containing 35 percent by weight vinylidene chloride, in particular Squeezing was satisfactory, and the peel-off special a vinylidene chloride-ethylenically un- tension was slightly lower than in Example I. saturated ester-itaconic acid copolymer, on top All vinylidene chloride copolymers which have at least 65 a gelatin undercoat (g) and then a at least 35 percent by weight vinylidene chloride carries antihalation layer (h). 1 sheet of drawings 409 597/333 5.64 © Bundesdruckerei Berlin