DE1151173B - Process for coating a substrate for a photographic film - Google Patents

Description

The invention relates to a method for coating a substrate for a photographic film.

A method is known for coating the support of a photographic varnish, in which of a device with slots for a liquid, binder-containing coating material this as thin layer applied to the layer support moving past the device and then is solidified on the substrate. With this procedure, only a single layer is applied applied to the substrate, which is relatively stable. Such a compact, self-supporting one However, the layer cannot be used as a film with an extremely thin layer, for example 0.001 mm, can be applied to the substrate as a separate layer of constant thickness and without defects.

From further publications are a method and an apparatus for producing Films are known, but no substrate is permanently provided with one or more coating layers will. The foils can therefore be easily peeled off from their base, with still it should be noted that the foils normally have a much greater layer thickness than the Coating layers on photographic film which can be as thin as Viooo mm. As the slides Yes, they have to be self-supporting, their layer thickness cannot be chosen too small. Since it is these publications only concern the production of self-supporting foils, these come in no way close to the subject matter of the invention, especially not because the present Invention is the coating of the support of a photographic film.

In contrast, the object of the present invention is a method for coating a layer support with two or more layers that remain separate from each other during and after application, that adjacent layers neither contaminate each other nor mix, so that in the end product each of the applied layers can perform different functions ·. It should be extremely thin layers are applied, which preferably have a thickness of 0.001 to 0.63 mm, which are in a certain relationship to each other.

This object is achieved according to the invention in that for the simultaneous application of several thin layers on a substrate a corresponding number of liquid, binder-containing coating materials by the corresponding An-method for coating a support for a photographic film

Applicant:

Eastman Kodak Company,
Rochester, NY (V. St. A.)

Representative: Dr.-Ing. W. Wolff, patent attorney,
Stuttgart N, Lange Str. 51

Claimed priority:
V. St. v. America 23 February 1955 (No. 489 863)

Theodore Alton Russell, Rochester, N.Y.

(V. St. A.),
has been named as the inventor

number of slots formed into thin liquid films of a given thickness and either individually or together over a shaping section and over one between a feed surface of the device and the layer support-forming droplets of the coating material in superimposed manner Arrangement are fed.

In the method according to the invention, the layers are passed over a forming section, preferably of constant cross-section, before they are applied to the substrate, which ensures a certain, constant layer thickness of the individual layers and thus a very specific ratio of the layer thicknesses within the multilayer coating compound. In the case of particularly low-viscosity coating compounds, the liquid tubes can be fed individually over feed sections, whereby a certain degree of solidification of the film surface is achieved, so that the liquid films are already present as separate layers of predetermined thickness when they are brought together. The method according to the invention also makes it possible to apply layers with extremely thin layers of 0.001 to about 0.63 mm on a photographic film , the layer thicknesses being in a certain ratio to one another and even with these extremely thin layers a perfect separation of the individual Shifts guarantee

309 619/179

3 4

is performing. Especially with photographic films, Fig. 1 is a schematic, partially cut

It is particularly important that the separation of the different sees one embodiment of a device, the one which layers is properly maintained, contains double funnel, the inventive because these are used in the film for a wide variety of purposes, applying two layers of a coating, can be used, for example, as emulsions of different materials on a tape; like spectral sensitivity, as atrium Fig. 2 is a partial section on an enlarged scale

Protective layers or the like by the one used in the device according to FIG

The method according to the invention ensures double funnels;

a perfect separation of the layers and thus FIG. 3 is a greatly enlarged section through the

a trouble-free process of their clearly delimited double funnel shown in Fig. 2 for explanation, of different functions, which is particularly important when it comes to how the two layers of the coating material is of importance to photographic Finns. applied simultaneously to the surface of the tape

In the method according to the invention, genes can be;

simultaneously one or more photosensitive Fig. 4 is a section of one with four ver emulsions and / or sub-layers, light filter-15 different layers provided color film, its Layers and protective layers on top of the base layers using a double funnel are applied, whereby for the production of coloring were applied;

sensitive material up to eight or more layers. Fig. 5 is an enlarged section through a

can be applied. When applying, triple funnel, if used according to the it may be necessary that a contaminant be applied to the 20 invention three coats Boundaries are absolutely avoided and the layer can;

thickness of the various layers strictly adhered to Fig. 6 is a front view of a multiple funnel,

must become. according to the invention for simultaneous

All of the applied layers can essentially be used from four layers; borrowed from water-permeable gelatin solutions 25 Fig. 7 is a plan view of part of the multi-standing, which is found only in the silver salt, the dye or the funnel according to FIG. 6;

others suspended or dispersed in the solution

differentiate yawed materials. Appropriately, line 8-8 of FIG. 6;

The coating materials are an aid to FIG. 8A shows in an enlarged detail of FIG

coating, e.g. B. a saponin, an alkyl sulfate 30 Fig. 8, as the four layers of the various Beod. Like., included. Layering materials through the funnel to the loading

According to the method according to the invention, drops of layering material are supplied; possible, a layer of the desired thickness from Fig. 9 shows a section through a double

Prepare each coating material and make this sliding funnel, with the two coats of coating layers in the desired orientation in the face material at the same time on the surface of a belt to bring surface contact and the surface of the can be applied;

Layer carrier to be supplied in such a combination. Fig. 10 shows a section through a multiple. At least the top loading funnel is expedient, through the four according to the invention Layering material over an upwardly open, ge layers of coating material simultaneously on the inclined surface passed as a feed path. 40 surface of a tape can be applied; this material in the form of a broad, thin stem- Fig. 11 is a section through a combined

fens fed to the surface of a belt press and slide funnel, with which according to the invention, which is moved across the slots and dung two layers of coating material evenly through a support roller or guide surface is applied smoothly to the surface of a belt is held. 45 can be, and

The FIG. 12 leaving the coating device is a section through a combined one

Layering material seeks, instead of the band un- press and slide funnel, with the one according to the invention In one layer to coat, the dung three layers of coating material at the same time has the same thickness in which the coating material can be applied.

the coating device leaves, then, 50 FIGS. 1 and 2 show a device with which on the side of the coating device at least two layers at the same time on a layer pile, on which the tape is led away. This carrier can be applied. The hopper 10 accumulating extends completely across the width has an outlet gap 11 with lips 12, the loading to be coated tape, and is normally a small distance from the surface of Banweise "as a" drop coating material having 55 of the W, the draws from behind by a roller 13. An enlarged cross section of a typi- is supported. This role serves to pull the band of conical layer material droplets at 17 in FIG. 3 continuously past the columns of the funnel. move. The coating material is here

The layer thickness of the fed on the passed double. A coating material S is deposited coating material is 60 in an upper inlet port 14 through a suitable determined by the action of the drop and depends on the pump P supplied, while the second coating is supplied by the speed of the belt movement, the processing material S ' continuously in the lower one-volume of the tape Binder-containing coating material nozzles 15 are closed by a separate pump P ' and so on. You do not necessarily need to be with the leads (see. Fig. 2).

Coater 65 Slot Size An adjustable partition 16 divides the interior

to match. of the funnel into two separate cavities and serves

The embodiments of the invention are to the two coating materials in the form of

explained on the basis of the drawing. thin layers L and L ' against the gap 11 of the

Funnel to direct. The funnel is made of translucent plastic. Different colored coating materials were used so that the behavior of the materials can be observed. It can be seen that the layer L of the material 5 which is introduced into the upper inlet port, through the full length of the exit gap 11, is above the layer L 'of the material S' which is introduced into the lower inlet port. When the two layers have reached the drop 17 between the lips of the funnel and the tape W , the separation of the layers in the drop is maintained in spite of the deformation of the drop that has occurred, and an enlarged cross-section of the coated tape shows after drying that the two Layers are clearly separated from one another and are extremely free of contamination or mixing at their interface and have a relative thickness comparable to the amount in which each coating material is fed into the hopper.

The funnel 10 can be provided with any suitable adjustment device so that the position of the exit gap 11 relative to the surface of the strip to be coated can be adjusted to the best proportions. For this purpose, the funnel is carried by a frame 18 which has bearing shells 9 which are rotatably mounted on the axis 8 of the support roller 13 to allow the adjustment device to pivot concentrically about the support roller 13, so that the position of the whole funnel around this support roller can be changed. The frame 18 can be fixed in any set position by a clamping screw 7 which engages in an arcuate recess 6 in the frame 19. The funnel itself can be pivoted at 20 in the frame 18 so that the angle of the exit gap 11 with respect to the surface of the strip to be coated can be precisely adjusted by adjusting the screw 5. To allow adjustment of the funnel towards and away from the belt W for adjusting the distance between the belt and the ends of the lips of the funnel, the funnel is slidably mounted on the frame 18 and connected to it by an adjusting screw 21. After the tape W has been provided with layers, it is necessary to allow the layers applied in this way to solidify and / or to dry. In the manufacture of photographic films or papers, the applied layers can be allowed to solidify by cooling before drying in order to limit the amount of relative flow between the layers or the lower layer and the surface of the belt. In such a case, the strip W after coating can be passed through a cooling chamber 22, then through a drying chamber 23 and then taken up by a roll 4. If the applied layers do not require cooling prior to drying, the cooling chamber 22 can be omitted.

It can be seen from Figures 2 and 3 that the coating material S which passes through the upper inlet port 14 is formed into a layer as it passes between the end of the partition 16 and the upper inclined wall 24 of the hopper. In the same way, the coating material S ' supplied through the lower inlet port 15 is formed into a layer when passing between the end of the partition wall 16 and the lower inclined wall 25 of the hopper. These two layers are brought into surface contact with one another immediately before or at the beginning of the outlet gap 11 of the funnel and are guided through this funnel in this combined form into the drop 17, in which, as shown in FIG. 3, the desired, clear separation of the layers is maintained ίο, the layers of this drop being applied simultaneously to the surface of the tape in the desired position of the layers to one another. It should be noted that the width of the exit gap 11 is not equal to the total thickness of the layers of the coating materials passed through, but it is preferably equal to the thickness of one of these layers or even slightly less. What is achieved thereby is that the speed of the combined layers L and L ' flowing through the exit gap 11 must be greater than that of the individual layers when they reach the gap. It must be twice as large if the two layers are of the same thickness and the compounds from which the layers are formed are introduced into the funnel in the same amount.

The width of the exit gap 11 and the slots forming the individual layers must be such that a suitable amount of the various coating materials can be fed to the drop 17. The thickness ratio with which the various coating materials are fed is determined by the desired thickness of the layers on the belt. If z. If, for example, the layer S is applied twice as thick as the layer S ', the gap widths are not varied, but twice as much coating material S is pumped into the funnel in the same time.

Tests have shown that the composition of the coating materials that can be applied by this method, as well as the relative thicknesses of the layers, the speed of application, etc., are largely unlimited. In an experiment with the dual feed funnel disclosed herein, a coarse-grained silver-bromide-iodide emulsion was pumped into the lower inlet port 15 and a non-diffusing, colored gel solution was pumped into the upper inlet port 14. The emulsion contained 2.43 kg of gelatin per mole of silver, with which it was possible to ^{coat approximately 15.8 m 2 of} the support. The colored gelatin solution contained approximately 7% dried gelatin. Both pumps were driven at the same time. The two coating materials were applied to a cellulose acetate base, one at a pump speed of 3.65 meters per minute and the other at a pump speed of 5.5 meters per minute. The two layers were allowed to solidify and dry in a known device at the same time. Enlarged cross-sections of the dried films showed excellent separation of the gelatin and emulsion layers and indicated that the relative thickness of the two layers was directly proportional to the rate at which the two coating materials were pumped into the funnel. Although the speed caused by the pump was 50% greater in one case than in the other,

7 8

there was no evidence that any duct material S forming the upper layer L had an adverse effect on the sharp separation of the was introduced into the upper inlet port 35. the

Has layers. three coating materials were then opposed

In another experiment, the colored exit slit 30 was replaced by layer-forming slits 36,

Gelatin of the above example passed through a 5 37 and 38, followed by the three in passage Replaced 7% clear gelatin solution and combined with a layer formed by this column

smaller pump fed. Here, too, showed transversely through the exit gap 30 in clearly separated areas

cuts of the films flowed the excellent separation of the strips. In this case the thickness was the

Gelatin and emulsion layers. middle layer L ' lower than that of the outer

In order to determine whether this coating process was sufficient because the average speed also when applying light-sensitive emulsions, the middle layer because of the friction of the outer ions, which are used in the production of colored layers on the walls of the exit gap larger films the following is taken as the average speed of the layers on a cellulose acetate support under outer layers. These layers mix using the 15 shown in FIGS. 1 to 3 also in the drop 17 applied between the funnel lips double feeding funnel, with and the belt W not, so that the three different films shown in FIG. 4 were produced. As shown in coating materials simultaneously on the tape in Fig. 4, this film consists of a clean layer to be deposited when the support or a tape Ψ made of cellulose acetate, tape is moved into contact with the drop, a blue-sensitive silver chloride bromide Emulsion R, a green-sensitive silver chloride emulsion, traverses the three separate layers through the drop of bromide emulsion G and a clear gelatin, different techniques were used, including layer C. Since only a double feeding funnel was used at Hch Photographic, immediate observation, the first two emul- 25x 5x magnification etc. became versions R and B simultaneously and without much success the third emulsion turns. While it was possible to determine the general, layer G and the clear gelatin layer C simultaneously, the external shape of the drop, it was even applied to the first two layers after these had completely dried using different colored solvents. gen practically impossible to an exact determination

In this color film, the blue-sensitive 30 of the ways to obtain the individual layers of emulsion take 7.58 kg of 5.6% gelatin and a yellow one, because at the edges of the drop the outer coupler per mole of silver and was in a thickness The first layers show the tendency to flow over the others to the 0.808 kg emulsion per 9.3 m ² , and thereby bring the view of the ^{layers, thus covering 87.5 m 2 of} separate layers. So since it was impossible to yield per mole of silver. The red-sensitive emulsion 35 is, the mutual position of the various layers contained 9.65 kg of 5.6% gelatin and a blue coupler during its passage through the drop exactly green coupler per mole of silver and was recorded in a thickness, the layers were in Fig. 5 applied accordingly to 0.808 kg per 9.3 m ² , with drawn, as it appears most likely, a coverage of 111.6 m ² per mole of silver. It is assumed that the top layer resulted on the. The green-sensitive emulsion contained 7.8 kg of the outer surface of the upper lip due to the accumulation of capillary 5.6% gelatin and a magenta coupler per molar action and / or surface tension, silver and was applied so as to form a layer in the middle Layer through the drop with a coverage of 89 m ² per mole of silver resulted. The clear, small deformation goes through and that the lower 7% gelatin was flowing backwards in a thickness corresponding to the layer and the space between 0.404 kg of solution per 9.3 m ^{2 was} applied. 45 see the end of the lower lip and the band W, cross-sectional samples of these films showed no major contamination between the stress fills due to the capillary action and / or surface vision, as shown in FIG. 5. It is likely that the shape of the droplet will be applied by both known methods to individual layers than layers of the same dimension, and of course the path that goes through it will be applied in only one layer. Photographic moving layers quite strongly with the test of this double-funnel coating speed, the viscosity of the color film gave as good results as according to coating materials and the effectiveness of the color films made by the known methods, when the funnel type changes. Regardless of the fact that only one layer was applied to them at a time. This conception of the drop shape and the shape of the In order to check whether three layers can be applied with this coating method, passing through the drop individually, layers cannot be applied correctly, was through the or not, a triple feeding funnel was used to test enlarged cross-sections of the type shown in Fig. 5 built in this. This funnel type of coated material has been unequivocally proven, 26 had an exit gap 30, the lips 32 of which were such that the individual layers of the various legs had a small distance from the surface of a 60 layering material through the drop in re-tape W passed through a roller 13 of the kind considered go through without mixing and that was that, as above, the tape of a multilayered material coated according to this technique could continuously move past the gap of the funnel - no more mixing or contamination. The coating material S ", which shows that between the layers as formed with the her base layer L" , was pumped into a lower relief port 33 made by conventional coating methods, which was found to have coating materials with each berial S ' , which formed the middle layer U , the layer material was only applied after the previous layer had completely dried in the middle inlet port 34 and the coating.

9 10

This triple feed hopper was tested in the preparation of the above-described four-layered funnel spacing from the lower surface of the upper hopper part 40 by exit gaps 59, 60 and 61 test color film. In this attempt to form the individual, separate coating, the blue-, the red- and the green-sensitive materials were formed into layers of controlled thickness and emulsion at the same time as superimposed 5 that conduct these layers to the exit gap 45, liquid layers with a coating speed the unification of the layers to facilitate speed of approximately 3.65 m per minute and by the thickness of the individual layers in the wear. After coating, the emulsions were allowed to regulate the funnel, each of the walls 48, 49 and 50 is solidified and dried at the same time with a device, through a pair of adjusting screws 62 and adjusting screws essentially adjustable with the io ben63 shown in FIG. By adjusting the screws 62 matched; the clear gelatin coating can be the width of each exit gap 59, 60 and 61 separately applied, allowed to solidify and adjusted to a desired amount, dried. After the desired setting has been made, each material is then applied individually, the walls can be locked in this position through the material in a known manner. After these two multi-layered color films each of the four flow channels is connected to one of the test series through neutral and colored wedges tube 64, at the other end of which one of the four feed tubes 65, 66, 67 or 68 was exposed and developed with a known color developer this photographic can be closed. Each of the four feed tubes tests identical results for the two films. The so with a reservoir of a coating color quality of the two films was excellent. materials connected. Showed From this reservoir These tests that no more mixing, the coating material by separate or contamination between the individual layers pump P in such amounts einauftritt into the hopper, when applied together, be pumped, that they during the application as if with which they applied individually; This fact - the desired thickness of the individual layers in a matter - was further corroborated by visual examination of certain proportions, enlarged cross-sections of the two films. If four different coating materials

After it has been found that two or three are fed simultaneously onto a belt through the feed pipes 65, 66, 67 and 68 in the different layers. Four layers are formed which can be carried and the separation of the 30 which through the Exit gap 45 of the funnel pass in layers without noticeable contamination or clearly separated layers and thus be applied to a tape W with a mixture obtained at the interface of the layers, while remaining, the question arose whether and which one can see that the tape over the entire width within the limit with regard to the number of different contacts with a drop in which the combined layers consist, which according to this coating layer can be applied simultaneously from the lips of the exit gap. the, stands. When the tape, as shown in Fig. 8,

Accordingly, if a four-tube, four-fold feeder is moved in a counterclockwise direction, the berender funnel will be of the layering material shown in FIGS. This was caused to occur simultaneously, applied directly to the strip surface by four different coating materials; the material entering through the supply tube 66 is determined on a tape, the individual coating material on which layers coming from the tube should remain clearly separated. These 65 coming coating material lie; The funnel is made up of an upper part 40 and a coating material part 41 entering below the inflow tube 67, which by two end plates 42 rial will form the next layer, and finally 43 and 43, which will be held together at the upper 45, is the one from the Inflow pipe 68 entering the coating and lower part fastened by bolts 44 forming the uppermost layer. In Fig. 8 are. The front edges of the top and bottom were the course of the four separate layers on part have a small distance from each other, so the tape because of the small scale of this figure that an exit gap 45 is created, which is not shown on the. However, the entire width of the funnel has been extended, this 50 largest section in FIG. The lower part 41 of the four separate layers of the coating material is provided with a chamber 46 which is connected rials through the exit slit of this four-tube trench to the exit slit of the funnel through a vex curved end wall 47 that passes through the drop to the strip. can, drawn. If the direction of movement of this chamber is through three walls extending over the entire 55 of the band W opposite the drop, the width of the funnel chamber 46, the order of the individual layers on 48, 49 and 50 is divided into four sections. Each reversed to the band. As already indicated above, these walls have a concavely curved surface, the relative thicknesses of the single surface 51 and a convexly curved surface 52 of the individual layers applied to the strip are not shown; the opposing pairs of these 60 from the width of the progressively narrowing through the upper part of the funnel formed outlet nut channels 53, 54, 55 and 56 by the individual walls and walls, which cause the split, rather than the crowd, in which the individual coating materials pumped into the funnel into the large parts of the channels will spread coating materials in the funnel. It has been found that the position of the various layers indicated above and in thin layers against the exit gap 45 65 are not printed. Each of the convex surfaces 52 is affected by the order in which the inlet and end walls 47 of the chamber 46 terminate in a pumping of the various solutions into the funnel substantially flat surface 57 or 58 which is commenced.

Water and behaves like a reversible colloid. Gelatin is also a colloid that occurs in warm Water is soluble. Samples produced according to the invention showed that the principle of simultaneous 5 Application of layers of different coating materials on a layer support even with colloidal materials that can be dissolved, is applicable. In another example of a three-layer

This four-tube, four-way feeding funnel
was made by coating a tape-shaped photographic support with black and clearer
Gelatin tested. The black one was used for the test
Gelatin by dispersing 2450 g of a 3.7%
metallic silver gelatin dispersion in 5500 g
10% photographic gelatin and 1070 cm ³
distilled water. The clear gelatin
was made from a solution of 6810 g of 10% photographic gelatin and 2850 cm ^{3 of} distilled 10% coating, which was prepared using the water shown in FIG. To each coating material, a triple-feeding funnel showed that 20 cm ^{3 of} a 7.5% saponin-present invention were prepared per liter, and a foll solution was added as a wetting agent. proceed as follows:

The test material was made by applying the The top layer consisted of a yellow, black gelatin as the first and third layer and 15 colloidal silver dispersion and 270 cm ^{3 of} one of the clear gelatin as the second and fourth layer - 7.5% saponin solution per 0.454 kg Gelatin disfigured. Using the 7% gelatin solution shown in FIGS. 6 to 8. The middle funnel shown was the above-mentioned series layer consisted of a 7% gelatin solution, which was followed by feeding the black gelatin into the 60 cm ^{3 of} a 7.5% strength saponin solution per 0.454 kg feed tubes 65 and 67 and the clear gelatin in Contained 20 gelatin. The lower layer consisted of the inlet tubes 66 and 68 and, by moving the 7.5% gelatin solution, which reached a black band W in the counterclockwise direction. metallic silver dispersion and 60 cm ^{3 of} a. After these layers had solidified and allowed to dry out 7.5% saponin solution per 0.454 kg of gelatin, a photomicrograph showed the hold. All three layers were laid out simultaneously on a cross-section such that each layer lay in the correct row of clear cellulose acetate tape of a thickness. In addition, it appeared that speaking 0.808 kg per 9.3 m ² per layer with a core intermingling or contamination of the single layers applied at 3.6 m per minute had occurred. After determining what a photomicrograph of a cross section showing four layers through this coating of this coated tape, a method of separation of the layers drawn simultaneously on a support was obtained. A number of applications were made, which can be applied. Saponin solution had no effect on the requests to determine what limits the layers remained separate during and after the nature of the coating materials being coated. However, if different coating materials were added with the help of this coating method, it would stand at the same time, clearly separated layers on a 35 so that the latter spread more easily and a smooth layer support can be applied. Give shift.

For this purpose, a light-sensitive emulsion was used. To find out what kind of influence the

Polyvinyl alcohol as a binder and another layering speed in the case of the invention

clear polyvinyl alcohol solution produced. Thus, the moderate procedure has been made using the

a cellulose 40 primed with a polyvinyl alcohol and the same coating

acetate substrates at a rate of materials as in the immediately preceding one

coated approximately 3.6 m per minute. For this example, but with a coating speed

The experiment shown in FIG. 4 was three times a shift of 5.4 m instead of 3.6 m per minute

leading funnel used, one chamber being made empty. Examining the photomicrograph of a

remained so that only two layers at a time on- 45 Cross-section of the coated tape after the

could be worn. The photosensitive drying of the layers clearly showed that the

The emulsion consisted of silver bromide in 4% aqueous layers at this coating speed

rigem polyvinyl alcohol also excellent separated with a _pH value = 6.0 and had and from

contained 60 cm ^{3 of} 7.5% saponin solution and 160 cm ³ that prepared according to the previous example

4% borax solution with a _pH value = 5.5. The only difference between the 5 ° layers is that each of the

clear polyvinyl alcohol solution consisted of 95 cm ³ layers approximately two-thirds as thick as that

a 7.5% saponin solution, 250 cm ^{3 of} a 4% solution at a speed of 3.6 m per minute

Borax solution and 0.454 g of a 6 "/ o aqueous supported layer.

Polyvinyl alcohol solution. The photosensitive emul- That the method according to the invention in others

Sion was applied directly to the support in a 55 colloidal coating materials as gelatin and

Thickness corresponding to 1.36 kg on 9.3 m ² applied polyvinyl alcohol is also applicable, was made by

and in a thickness corresponding to 0.68 kg per 9.3 m ² the following example proved:

covered with a clear polyvinyl alcohol solution. The colloid used in this experiment was

After coating, the layers were left with cellulose phthalate ether. It was made from ethyl cellulose,

Room temperature in an ammonia atmosphere 6n which had an ethoxyl content of approximately 45%,

solidify as in U.S. Patent 2,376,371 according to the method of U.S. Patent

is described. Transverse 2,093,462 were made of this material and had a phthalyl content

sections made, with two of 16.8% under the microscope. The cellulose phthalate ether is in shape

clearly separated layers were visible and a salt, e.g. B. an ammonium salt, in water

showed no mixing of the two layers. 65 soluble. According to the invention, two layers were made

Commercially available polyvinyl alcohol is hydrolyzed this material on a cellulose acetate layer-

Polyvinyl acetate and contains approximately 5% polyvinyl carrier in a thickness corresponding to 0.57 kg per 9.3 m ²

acetate. It dissolves easily at room temperature with a coating speed of 1.8 m

i 151 173

13 14

applied per minute. The upper layer consisted of let nozzle 82 by means of another pump P with

from the ammonium salt of cellulose phthalate ether, at a constant rate, into a second the lower layer additionally contained 1 part of a cavity 81 pumped from where it was pumped through a narrow Carbon dispersion on 9 parts of cellulose phthalate vertical gap 83 in the form of a ribbon. The carbon dispersion was forced into a 5 and onto a second, downward sloping slide

Coating material added to determine area 84 is guided. This tape of the second

whether the two layers are clearly separated without any layering material forming when under the influence the interface of the layers impurities or gravity flowing down on the

to show a mingling. Photomicrographs of sliding surface 84 a smooth, uniformly thick layer 85.

of a cross-section of the Celluloseace- io coated in this way. The two sliding surfaces 78 and 84 lie in one plane

tat substrate clearly showed that loading or essentially in a plane so that the

Layering materials also have a good separation layer 85 of the second coating material

of the layers is obtained. the layer 79 of the first, out through the gap 77

The following example shows that it is possible to flow up in pressed coating material when

In accordance with the present invention it reaches this point, after which the two layers

two layers of a non-colloidal coating on the sliding surface 78 together down into the

materials at the same time and still a drop of 17 'flow. The relative thickness of the two

to get good separation between the layers. Layers depends on the amount in which the loading

There were two layers of a polymeric, non-layering materials in their cavities 75 and 81

peptized from a sol, but pumped in from a coarser 20. The funnel is with tubes 86

Dispersion of polymer particles in water provided by the hot or cold liquids

standing coating material can be performed with good results in order to

nits upset. These coating materials are supplied in the desired, liquid state

were held three times with the one shown in FIG.

The leading funnel prepared for two-ply coatings, that is, the middle part was of this type, a photographic gelatin was sealed off, and the coating materials became silver halide emulsion and a protective layer through only the upper and lower inlet ports transparent gelatin is fed to a barite at the same time. The experiment was applied with a commercially available paper about 1 m wide with a speed of 30.5 m per minute aqueous dispersion of an acrylate resin. It was led. The upper layer consisted of clear acrylic photographic paper made of the same good lathe resin, while the lower layer had the same properties as a paper in which the two acrylate resin consisted of which, in order to separate the layers, were applied one after the other and in both cases Layers to show an aqueous dispersion to which the emulsion layer has been added completely dried by carbon particles. Both layers ₃₅ were applied before the protective gelatin layer was applied at a speed of 1.8 m each. It has been found that it is expedient to apply a negative pressure to the drops at a thickness corresponding to 0.567 kg per minute, as applied to 9.3 m ² . After these layers are described on US Pat. No. 2,681,294. Substrate were applied, water was This example clearly shows that this method does not evaporate, coalesced after which the particles of the polymeric loading ₄₀ to the coating of sheets of narrow width layering material and formed continuous and small coating speeds benuierliche layers of the polymer. One is limited, but equally for the microphotograph of the dried coating, layers of support with commercially available layers showed an excellent separation between the clear width using high coating and the black layer. ₄₅ speeds is suitable.

This method of coating a layer- In Fig. 10 a quadruple sliding funnel is shown,

The carrier is not restricted to the use of the already used four separate layers of the

Written, express the coating material - same or different coating materials

the funnel, but can be successfully applied simultaneously to the surface of a belt in over-

even with certain advantages, also with other types 50 in accordance with the present invention.

be carried out by coating equipment. can be brought. With this facility

Thus, in Fig. 9 there is shown a double slide hopper, the first coating material being pumped continuously with two layers applied simultaneously by using it in accordance with a given rate in the chamber 90 of the invention, of which it can be applied through a narrow perpendicular. In this funnel the one, ₅₅ gap is pressed outwardly on the downwardly inclined sliding liquid coating material 74 by a pump P surface 92, through which it flows in the form of a continuously through an inlet port 76 with layer due to gravity downwards. The other coating is pumped at constant speed into the cavity 75 in the same way, from where it is continuously forced through a narrow vertical material into the chambers 93, 94 gap 77 in the shape of a belt 60 and 95 and pumped through the narrow vertical material and then outside , on the downwardly inclined sliding column 96, 97 and 98 on the sliding surfaces 99, 100 surface 78, under the influence of gravity in the form and 101 pressed, from where it flows down due to gravity of a layer 79 to a point, separated in the form Layers flow downwards. The one of the drops 17 'between the end of the four sliding surfaces lie in one plane, so that when the sliding surface and the band W forms. The band W 65, the layers of the various coating materials, will flow downwards across the entire width of the rials on their sliding surfaces through a support roller 13, it will move upwards in contact with the drop. The overlay and, when the four layers reach the drop of second coating material 80 through the one 17 ", they are layered in the desired one

Kind are united. These layers remain separated when passing through the drop, so that if the tape is moved in contact with the drop, the latter the four layers on its surface records in the order you want. The layers are clearly separated from each other, and its thickness is related to the amount of coating materials pumped into the hopper, in a certain proportion.

Layering material flows down the sliding surface 121 , it forms into a layer 129 of the desired thickness and smoothness. It is noted that the gaps 122 and 125 and the lower end of the sliding surface 128 5 are arranged so that in each case the three layers individually formed thereby or thereon are brought together into contact with one another just before the three layers are in the gob 17 "'enter and before being applied to the tape

the more pressing type or the slide hopper type, but is equally limited in use a combination of these two types of funnels.

In Fig. 11, a funnel is shown, which such a combination of a simple sliding funnel with a simple hopper as proposed by Wilson et al. shows. In this facility

This method of coating a layer will be io. So the three layers step into the drop The carrier is not limited to the use of funnels and will be different on the belt

and separate layers and are arranged so that the layer of coating material Z is adjacent to the tape, the layer of coating material Z 'directly on the layer of solution Z and the layer of coating material Z "the outermost of the three layers and in contact with layer Z ' is a feature by which this funnel shape differs from the double press funnel

If the one liquid coating material X is differentiated according to FIGS. 2 and 3, it is continuously pumped into the chamber 110 and from there that each funnel chamber has its own gap (122 as a layer 111 from the essentially horizontal and vertical 125) so that the layers of the individual right-hand exit gap 112 do not collide directly in the drop 17 "'of coating materials, pressed over and into contact with before they have passed the gap. This shows that the belt W is in the direction of the arrow is moved along the 25, the present method for simultaneously AufOberfläche the roller. 13 the other do not carry multiple layers limited to coating material Y is continuous with one, the individual layers a substantial period of the given span speed overall in the chamber 113 prior to the time to form and pumped together and is brought about by the essentially horizon- tally at which it is in the drop e in the valley gap 114 as a band on the downward sloping 30, but that the individual layers also surface 115 are pressed out. The fact that the coating is combined immediately before or simultaneously with the single material on the sliding surface 115 under the influence of the step in the drop and that gravity flows downwards, it forms into a number of separate layers can be obtained. Layer 116 of the desired thickness and is put into contact with layer 111 of the other coating with success for simultaneous application of sealing material at the moment when the one of these types of the commonly used light-last-mentioned layer leaves the exit gap 112 , sensitive gelatin silver halide emulsions so that it combines in the drops 17 enter. '"and gelatin protective layers or for the simultaneous These two layers are in accordance with the invention, application of color light-sensitive emulsions, received by the band W and appear to 40 which for producing of color films, the tape after drying is used as two separate ones.In this case, the product was coated with several layers after this and different layers, which are placed on top of one another, so that the product pressed out of the exit gap 112 in every respect just as well - both phy The physical layer 111 lies directly on the surface of the belt as well as chemically - such as in the known manner and the layer 116 45 formed on the sliding surface by successive application of the shifted layer 111 lies. those layers after completely drying

In Fig. 12 a funnel is shown containing a product coated in each layer. These funnel-shaped sliding funnels with two press funnels have been used particularly successfully for coating, in accordance with the proposal by Wilson et al., Belts that were 112.4 cm wide and unified, and when used three layers in 50 at a speed between 7.3 and 30 m in accordance with the present invention were coated at per minute,
a tape can be applied. At this it cannot be explained why two or

In the device, a coating material Z is continuously pumped into a chamber 120 and, in accordance with the invention, a layer 121 from the upwardly inclined gap 55 is not mixed onto a belt, 122 directly into the drop 17 '"is pressed, over which, rather than layers, so clearly separated and so away and in contact with it, a belt W is moved around the support roller 13 in the direction of the arrow, free of mixing and contamination. The boundary surface remains as if the same A second coating material Continuous materials are pumped sequentially at a known rate at a known rate into the opening of each layer prior to application of the next chamber 123 and applied as a layer 124 of layer. This does not base a substantially horizontal gap 125 directly on top of it that the various coatings gsmate pressed onto the drop 17 '". The third material, physically or chemically non-interleaving, Z "will be continuously miscible with one another because, as the examples show, known speeds into chamber 126 will give the same results if all pumps and is band-shaped through one Essentially, coating materials both physically as a horizontal gap 127 are pressed onto a downwardly as well as chemically identical to one another with the inclined sliding surface 128. By this exception that in one of them a dye

or carbon dispersion was incorporated to obtain visual evidence of this phenomenon.

When trying to research the reasons why the different layers of coating materials do not mix when applied according to the present invention, the Question considered whether this case is from the form of fluid movement known as "laminar flow" which is in contrast to the form of motion known as "turbulent flow". To Reynolds theory of fluid flow (R. C. Binder, "Fluid Mechanics", Prentice Hall, 1943, p. 71), two separate streams of water flowing through a pipe remain laminar Flow separated as long as the critical speed has not yet been reached; after reaching At the critical speed, the flow becomes turbulent and the flows mix. Reynold showed that the critical speed depends on the diameter of the tube and on the speed the density and viscosity of the liquids depends and that when these four factors combined in a certain way to obtain the function known as Reynolds number which indicates the critical velocity for the flow of a liquid through a pipe. While this theory assumes that the flow is laminar, because according to Reynolds The number the critical speed has not yet been reached can be used to explain this can explain why the separate layers come through the exit slit in a united form as they pass of an illustrated press funnel, this theory does not appear to be applicable, if multiple slide funnels or combined slide and press funnels are used. She appears nor can it be used to explain why the layers are separated by the drop and is maintained after application to the tape because the layers are not here move through a tube and are also not completely limited in any way. An explanation for this phenomenon that may be put forward is that it is usually an estimable time takes to mix two solutions even when brought together in such a way that turbulence arises. In the present method for coating a The various layers are not backed up before they are applied to the tape combined so long that a noticeable mixing can occur, even in the event that the flow conditions are such that such mixing can occur support financially. The fact why the layers split their between the time in which they are applied to the tape and maintained at the point in time when they are completely dry, is inexplicable, except in the case of coating materials, which can be obtained by cooling, heating or by chemical action immediately after application to the tape surface and solidifies before drying. Here again, time can be the critical factor, as the time span that between the application of the layers on the tape and the time at which the layer has dried is, is relatively short and perhaps less than the length of time that is required, so that the layers or the substances dispersed in them diffuse into one another.

As indicated above, the manufacture of photographic films includes attachment of gelatin protective layers from aqueous solutions on this the layer at the time in which it is applied, liquid. To complete the drying of the layers, it is it is advisable to let it solidify first.

ίο This can be done chemically according to the item U.S. Patent 2,652,345, where recommended, on the coating material adding an aldehyde and then after coating to rapidly solidify the layer to allow gaseous ammonia to act on the latter.

The method of coating a support has been found to be solidification such coating materials chemically in an immediate and convenient manner without the use of gaseous ammonia, without a freshly coated tape of such gas treatment having to submit and without the risk of the fresh surfaces of the layers through to roughen the introduction of the gas under pressure makes possible.

If in the present method two different proteinaceous coating materials on one Substrate are applied and an aldehyde,

z. B. formaldehyde, in one solution and ammonia in the other, diffuse the Ammonia and the formaldehyde presumably pass through both layers when they are coated come together and freeze them at the same time.

The following layers were solidified chemically and showed no effect on the clear separation of the two layers applied to the substrate. A Be-layering material (1), which consisted of a silver bromidjodid emulsion contained and 60 cm ³ 7.5% sodium saponin and 20 cm ³ lO ^fl / oiges formaldehyde per mole of silver and 7% dry gelatin a p _H -value = 6.0 had, and another coating material (2) having a 7 ^fl / o, clear gelatin solution, 60 cm ³ 7.5 ° / oiges saponin and so much contained NH ₄ OH in that the _pH value rose to 8 were co-coated onto an acetate support using the dual funnel shown in Figure 2 at a rate of approximately 3.6 meters per minute. The emulsion was applied in a thickness ^{corresponding to 1.362 kg per 9.3 m 2} , the gelatin solution was applied on top of the emulsion layer in a thickness corresponding to ^{0.68 kg of gelatin solution per 9.3 m 2.} In another experiment, the same materials were applied in the same way as the first time, but with the layering reversed, ie the emulsion layer came on top of the wet gelatin layer. In a third experiment, the two materials in the same manner as were applied on the first attempt, however, had the gelatin solution has a _pH value = 9.0. All these tests resulted in a good separation of the two layers, despite the fact that the formaldehyde and the ammonia diffused freely between the two layers and allowed them to solidify chemically in a very short time.

309 619/179

The invention is not intended to be restricted to the described embodiments of the method.

Claims (6)

PATENT CLAIMS: 1. A method for coating a substrate for a photographic film, in which a liquid, binder-containing coating material is applied as a thin layer to the substrate moving past the device and then solidified on the substrate by a device with slots, characterized in that for Simultaneous application of several thin layers on a substrate a corresponding number of liquid, binder-containing coating materials through the corresponding number of slots into thin liquid films (L, L ', 79, 85) of a given thickness and formed either individually or together over a forming section (11, 30, 36, 37, 38, 45, 53 to 56, 77, 83, 91, 96, 97, 98, 114, 122, 127) and via a drop of the coating material (17) that forms between a feed surface of the device and the substrate. are supplied in a superimposed arrangement. 2. The method according to claim 1, characterized in that at least the topmost coating material via an open top, inclined surface (78, 84, 92, 99, 100, 101, 115, 128) is routed as a feed line. 3. The method according to claims 1 and 2, characterized in that the layers in a multiple slot caster with the layers on at least one mouthpiece of the slot die. 4. The method according to any one of claims 1 to 3, characterized in that at least a coating material is used which optionally contains a gelatin solution containing silver halide or polyvinyl alcohol solution. 5. The method according to any one of claims 1 to 4, characterized in that at least one of the coating materials an aldehyde and at least one further coating material Ammonia is added. 6. The method according to any one of claims 1 to 5, characterized in that an aldehyde-containing Protein coating material and at the same time an ammonia-containing one for another layer Coating material is used. Considered publications:
German patent specifications No. 484 646, 579 046,
604112, 842402; U.S. Patent No. 2,681,294. For this purpose 2 sheets of drawings © 309 619/179 6.