DD138711B1 - METHOD FOR MATTERING PHOTOGRAPHIC MATERIALS - Google Patents

Description

Method for matting photographic

materials

field of use äev invention

The invention relates to a method for matting. photographic materials.

Builds character ri sti k _the known technical rule Lös Ungen

It is known to matt surfaces of photographic layers by adding inorganic or organic pigments or synthetic polymers. On this occasion, a surface roughness is obtained which ensures a good retouchability and suppresses the formation of Newton's rings in the copying process. It is desirable to choose such a matting substance that is photographically inactive and has a refractive index equal to that of dry gelatin in order to avoid haze phenomena and sharpness losses due to stray light. Furthermore, the matted surfaces should have low abrasion and be resistant to fingerprints.

In DT-AS 1 547 639, it is proposed to add amorphous silica as matting agent. However, this has the disadvantage that it tends to agglomerate at higher temperatures and is therefore difficult to filter. Alkaline earth metal salts, as described in US Pat. PS 2,823,136. They have too high a density and too much opacity, which leads to impairment of the photographic property. Further matting options are the addition of wax (DD-PS 35 234), hardened gelatin (DT-OS 2 522 692), cellulose derivatives (DRP 725 698) or dispersions based on synthetic polymers. However, these known methods are associated with a number of slopes In. For example, wax-matted layers show an unsatisfactory roughness because it is partially lost during the drying process. Starch, cellulose derivatives and hardened gelatin are difficult to access in the desired particle size range and sometimes lose their leaching effect at high humidities. Synthetic polymer dispersions have the advantage that their matting effect is not diminished by rapid settling during molding. Polystyrene dispersions (GB Pat. No. 645,954) are known as such. "Dispersions based on styrene copolymers (BE-PS 634 174, DT-OS 2,628,643) and polymethyl methacrylate.

However, it is very difficult to prepare stable dispersions with uniform particle distribution with polystyrene resins.

Since polystyrene as well as Polymctliylmethacrylat differ significantly in the refractive index of gelatin, show with these dispersions matted photographic materials increased turbidity and sharpness losses, their production is also very expensive and difficult to reproduce

 Another disadvantage of many matting agents is that they do not have the desired spherical shape.

Object of the invention

The aim of the invention is an improved method for matting of photographic materials, which allows a more uniform matting, turbidity phenomena and scattered light v. By the matting agent v. Should be excluded vith first and the matting agent can be produced easily and reproducibly.

Presentation of the ѵ / епепв the invention

The invention is based on the object, by using new Polyüierdispercionen for matting of photographic materials Kachteilo .bekannte processes, such as increased turbidity and sharpness loss by unfavorable refractive index de matting agent, lack of stability during the casting process and lack of matting or Begießstörungen by unfavorable particle distribution to eliminate.

According to the invention the object is achieved by the fact that 7.5 to 20 wt as a matting agent, a polymer dispersion based on polyvinyl chloride or Vinylchloridmischpolymerisaten obtained by microsuspension or seed polymerization, in a concentration of 5 to 50 parts by fS, voTOUssweise -.%, Based is used on the binding delta dry film of the layer to be matted.

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These polymer dispersions have a narrow particle size distribution. They can be prepared in a size of 0.1 to 5 / um to DT-AS 1 301 529 or GB-PS 978 875 (Ыікговиз-pensionspolymerisaticn) or DT-OS 2054 108 (seed polymer ion.

They tend in the aqueous phase without additional protective colloids to Se dime n, t at ion without agglomeration. By weight by the addition of 20 to 500 wt .-% of protective colloid, preferably 100 to 200 -.% Gelatin, based on the polymer, very stable dispersions can be obtained by v / ground. Erfindagemaß this can be used without prior solidification in liquid form as Uattierungsdispersion verv / ends. However, it is also possible to allow the dispersions to solidify after the gelatin solution has been added and to store the gels. There is no change in the particle size and particle size distribution even after storage at 278 ^° K for several months. The gels can be melted well and diluted with water or gelatin solution. It is also possible to dry the gels. To achieve a rapid redispersion, it is advantageous to use this пасіз. or to granulate during drying. According to the invention, silver halide layers, protective layers, filter layers, as well as ITC layers can be matted by the new matting process. The novel cladding method is characterized in that the dulling dispersions used can be easily prepared without the use of high-speed dispersers having the desired particle size and narrow particle size distribution. As a result, an effective roughening is achieved at particle sizes of 0.1 to 5 μm even at a low concentration of matting agent.

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Since the refractive index of the vinyl chloride polymers with 1 »538 almost corresponds to that of gelatin, turbidity phenomena and sharpness losses are avoided. The particles in the form of the dispersions are very stable to agglomeration and dimensionally stable even at high humidities. Gelatin stabilized and dried after solidification, they can be stored for long periods without additional cooling capacity and redispersed as needed in water or aqueous protective colloid solution. The process of the invention provides the ability to produce particularly fine grained frosted gelatin layers.

Execution sbeis pie le

example 1

Preparation of matting dispersion

Matting Discovery A

In 14 1 of water, 1 kg of gelatin are swollen and melted. For this purpose, 2 kg of polymethyl methacrylate at 318 K, solved in 11.4 1 Llethylenchlorid, and dispersed by means of a high-speed stirrer. After completion of the dispersion, the methylene chloride is removed and the dispersion is solidified at 283 K. The average particle diameter of the polymer particles is 0.478 / μm. The refractive index of the polymer particles is 1.492.

Matting diaperaion B

In 9.5 1 v / asser 1 kg of gelatin are swollen and melted. For this purpose, at 323 K under conventional low-speed stirring, 6.45 kg of a 31 wt.

vinyl chloride dispersion prepared by microsuspension polymerization, having a mean particle diameter of 0.481, added thereto. After completion of the addition, the mixture is solidified at 283K. The refractive index of the polymer particles is 1.538,

ISattierunsicrokerion C-E

The matting dispersions C to E are prepared analogously to the matting dispersion B, using polyvinyl chloride dispersions of different particle size.

Mat animals, saispersi on

average particle diameter

Mat tie г \ xnp- s?. e 1 at i ne

0.789 / um 0.948 / do 1,312 лш

10 1 Matting Dispersion B are solidified and solidified at 283K. The resulting gel is cut into about 2 cubic cubes and air dried at 3C8K for 48 hours. Thereafter, it is comminuted again by granulating. A slightly turbid granulate is obtained, which in the following example is referred to as lattice gelatine.

Example 2

1.2 l of matting dispersion A are dissolved in 100 l of a 2% strength aqueous gelatin solution at 313 K. This dispersion is poured onto a halosilane emulsion layer as a protective layer.

The dried protective layer is well retuachable, has a roughness of 1.1 / um and shows little Uewtonian rings when copying,

Example 3

The procedure of Example 2 is repeated using 1.2 kg of sheet dispersion B. The dried protective layer has the following characteristics:

Retouchability: very good Roughness: 1,2, um

Kewton's rings: none

Example 4

The procedure of Example 2 is repeated using 4.8 kg of matting dispersion A and 3. The dried protective layers have the following characteristics:

A B

Retouchability: very good very good

Surface roughness: 1,6 1,7

Kewton's rings: none none

The material with the protective layer based on the matting dispersion A v ^ ar very cloudy and showed very strong sharpness loss.

Example 5-7

The procedure of Example 2 is repeated, using 4.8 kg of dispersion C, D, E.

8th -

The dried protective layers have the following characteristics:

Mint dispersion C D E

Retractability very good very good very good

Roughness 2.8 2.8 3.1-3.2

Newtonian rings None None None

Example 8

The procedure of Example 2 is repeated, wherein 0.45 kg of matting gelatin are swollen in 100 l of a 1.5 SS gelatin solution at 313 K for 20 minutes and then redispersed with stirring

 The dried protective layer has the following characteristics:

Retouchability: very good

Roughness: 1.4 / um

Newtonian rings: none

Example 9

On a teaching surface color material whose green sensitive silver halber color coupler emulsion layer contains a stabilizer, a curing agent, a wetting agent, the magenta coupler Z 169 (Bios Final Rep. 721, 21, 1946) and the usual additives, a protective layer according to Example 3 is poured , The matting by means of matting dispersion B does not impair the photographic properties. When stored at 90 % humidity, no adhesion tendency of the backing layer is observed with the Schutsschicht.

On the other hand, a comparison material without matting impression B in the protective layer shows considerable sticking tendency, which leads to damage of the backing layer and protective layer under mechanical stress.

Claims (1)

invention claim Process for the matting of photographic materials, in particular of silver halide layers, protective layers or ITC layers by means of polymer dispersions, characterized in that a polymer dispersion based on polyvinyl chloride or vinyl chloride polymerizates, obtained by microsuspension polymerization or seed polymerization, in a concentration of 5-50 Gev / - jS, preferably 7, * 5-20 Gev /%, based on the binder dry weight of the layer to be matted.