DE1211488B - Device for the simultaneous application of several layers - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

GERMAN

PATENT OFFICE

EDITORIAL

Int. Cl .:

G03d

German class: 57c-5

Number: 1211488

File number: E 11998IX a / 57 c

Filing date: February 22, 1956

Opening day: February 24, 1966

The present invention relates to a device for the simultaneous application of several Laying of liquid layer materials on a continuously moving past the application site Film carrier tape for the production of multilayer photographic recording materials according to the method described in patent 1,151,173.

Multi-layer coatings have heretofore been produced by first applying a layer to the Carrier applied, this layer then dried, then the second layer and only after it Drying the third layer, etc. has applied. In contrast, in the above-mentioned patent a process for the application of several mutually separated photographic layers describes the surface of a moving substrate that allows all layers to be applied simultaneously to be applied to the carrier, with a sharp separation between the individual after application Layers are maintained. Essentially, the method consists in the fact that a corresponding Number of liquid binder-containing coating materials by a corresponding number formed by slits into thin liquid films and, either individually or together, over a forming section and over a between a feed surface of the device and the Layer support forming drops of the coating material in a superimposed arrangement are fed.

When coating a shaft support, e.g. B. uninterrupted tapes, which on one of its surface has two or more layer materials in separate, superimposed layers avf , a known method has been used which consists in that each of the layers is applied successively and each layer is solidified and or Let dry before the next layer is applied. Such a process appeared to be necessary in order to obtain properly separated layers and to prevent mixing of the layer materials or the contamination of one material by the other material at the interfaces of the layers. It is evident that such a method of applying a coating of several layers to the surface of a support is very time-consuming and involves the use of several devices for each coating according to the number of layers. These two factors alone account for most of the work involved in loading a simultaneous application device
multiple layers

Addendum to the patent: 1151173

Applicant:

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

Representative:

Dr.-Ing. VV. Wolff, patent attorney,

Stuttgart N, Lange Str. 51

Named as inventor:

Theodore Alton Russell,

Richard MacCuaig Wilson,

Carleton Robinson Sanford, Rochester, N.Y.

(V. St. A.)

Claimed priority:
V. St. v. America February 23, 1955
(489 861)

Layer carrier with several superimposed layers of necessary effort. In the above Patent describes a method that the simultaneous application of a plurality of separate Layer materials allowed on a surface of a substrate, whereby the in the Coating process required time and the multiple facilities reduced in each case will or become superfluous.

Experiments have shown that applied to the surface of a layer support by this method multilayer coatings produce equally good results, both physically and chemically, in terms of the clean separation of the layers show how the multilayer coatings according to the known technique can be applied, with each layer fully cured or dried before the next layer is applied.

The present invention relates to a particular type of one for carrying out this new method device suitable for applying multi-layer coatings and is characterized by several

609 509/17 &

Liquid chambers each provided with a slit-shaped outlet channel, some of the outlet channels immediately in front of the guide track of the carrier tape to be coated in one of its thickness somewhat the excess distance ends, partly open into an inclined sliding surface above the application site, and by pumping devices, which continuously feed the sheet materials in one of the desired Press layer thickness corresponding amount through the chambers and their outlet channels, so that the flowing off under the influence of gravity over the inclined surface in the form of a thin ribbon Layer material lies over the layer tape emerging immediately in front of the guideway and collapses with this is taken up by the carrier tape guided past the application point.

Generally speaking, this apparatus includes a multiple feed hopper incorporated therein Case is a combination of one or more press funnels with one or more sliding surfaces, which are arranged so that the separated sheet materials are first formed into individual layers and that these are then combined to form a stacked layer arrangement, before they or at the moment when they turn into a drop of layer material. That moved Film carrier tape picks up as it moves across and in contact over this drop of film material is, the combined layer material layers on its surface at the same time, and the layers the individual layer materials remain even after application to the tape surface and over beyond the time they are completely dried, neatly separated.

A particular advantage of the invention is that layers applied with this device also at their boundary layers are sharply separated from each other and even after they are completely When dry, no mixing of the individual layer materials was found at the boundary layers can become, which is particularly the case with a film or paper comprising several photographic layers important is. With the aid of the device according to the invention, the production of multilayer Coatings on a carrier are significantly shortened and cheaper.

In the device according to the invention, part of the layer material is formed in layers as a result, that it is continuously conveyed to the upper end of a sliding surface on which it is during of sliding down into a layer tape of uniform thickness, while another layer material is formed into a layer of uniform thickness by squeezing it through a corresponding channel will. Shortly before it hits the edge of the device, the carrier to be coated is closest, the layers formed in the various ways mentioned are superposed on one another and applied to the surface of the support.

In one embodiment of the device according to the invention this has two chambers, whose Outlet channel of one chamber immediately in front of the guide track of the carrier tape to be coated ends in a distance slightly exceeding its thickness and the outlet channel of the other Chamber opens into the sliding surface attached above the application site.

In further embodiments of the application devices according to the invention, several Sliding surfaces that form layers and channels that form a plurality of layers may be provided, wherein the layers are all applied on top of one another and at the same time on the carrier.

The new features of the invention emerge from the patent claims. The invention is on Hand of three exemplary embodiments in the following description in conjunction with the drawing explained in more detail.

F i g. 1 is a schematic view of a multiple feeding coating apparatus according to the present invention;

F i g. 2 is a side view, partly in section, of a dual feeding device according to FIG Embodiment of the present invention in connection with a tape to be coated;

F i g. 3 shows in a similar side view as

so F i g. 2 another embodiment of the device, with which three separate layer materials can be carried to the application point, two by squeezing and one under the action of gravity;

F i g. Figure 4 is a vertical section through another embodiment of the multiple feeder Device suitable for feeding four separate layer materials to the point of application, two by squeezing and two under the action of gravity.

In the F i g. 1 and 2 is an apparatus constructed in accordance with an embodiment of the invention shown used in the manufacture of photographic films with success for the application of two

superimposed separate layers on a support. It contains an outlet channel, which ends immediately in front of the layer support, of the funnel-like component designated as a whole by 10, which is united with a sliding surface of the part designated as a whole by 11 in such a way that the layers L and L ₁ formed by each of these parts of the individual Layer materials are combined on their surface before they or at the moment in which they pass into a layer material drop 17, which is maintained between the exit lip 61 of the part 10 and the surface of the layer carrier belt W moved continuously in contact over the drop by a support roller 13, the roller also serves to hold the tape taut and smooth at this point.

The component 10 contains a chamber 15, into which a liquid layer material S is continuously fed at a known rate by means of a metering pump P through an inlet connection 14. From the chamber 15 the sheet material is pushed through an elongated narrow gap 16 which forms the sheet material into a layer L and which merges into the sheet material drop 17 which is maintained between the mouth lip 61 and the band which is spaced from the lip, the belt W being moved across this drop to pick up a layer of sheet material therefrom. This "drop" application technique is known and is characterized by an accumulation of coating material between the lips of the lip 61 and the end of the sliding surface 21 and the surface to be coated

Material tends to accumulate or accumulate the material on the side of the lip that is in the Direction of movement of the carrier tape lies. This piling or accumulation extends across the full width of the carrier tape to be coated and is commonly referred to as a "coating material drop" or a drop of layer material. In Fig. 2 the shape of the drop is drawn, believed to be formed in the present device; also are the ways which the individual layers presumably take through the drop of layer material. It should be noted, however, that this is only a guess as it has been proven it is practically impossible to see what is really going on inside the drop. But you can see that at With this drop application technique, the coatings are actually not immediately off the lip 61 as well the end of the sliding surface are applied to the belt surface, but that this only the Maintaining layer material drops and the carrier tape is covered by this drop. With With the drop application technique, the real thickness is applied to the moving belt Layer determined by the action of the drop and is made with the speed of the belt movement the amount of layer material etc. added per unit of time, but is not necessary equal to the thickness of the layers formed by the gaps of the combined outlet channels or the Be the thickness of the layers at the transition in the layer material drop 17.

The component forming the sliding surface contains a chamber 18 into which a liquid layer material S ' is continuously fed through an inlet connection 19 by means of a metering pump P at a known speed. From this chamber the layer material 5 'is guided through an elongated, essentially horizontal exit gap 20 to the outside onto a downwardly inclined sliding surface 21 in the form of a belt, this layer material flowing downwards on this surface 21 to form the layer L _1. This sliding surface 21 forms an acute angle with the upper wall of the outlet gap 16 so that the layer L ₁ , when it leaves the sliding surface, unites on its surface with the layer L emerging from the outlet gap 16 at or just before this point in time , to which the two layers in the layer material drop 17 merge. This clean separation between layers L and L ₁ is maintained throughout the time that the two layers are moving through the drop and even after the two layers have been simultaneously picked up by the surface of the one carrier tape which is transverse and in contact moved over this drop. An enlarged cross-section of a coated tape after drying showed that the two layers are sharply separated, the interfaces between the layers are extremely free from contamination or mixing, and that the layers have a relative thickness which is in some proportion to the amount in which each layer material was pumped into the chambers. The thickness of the layers applied to the tape can and usually will be different from the thickness of the same layers as they enter the drop because of the drop effect; however, for the sake of illustration, the layers applied to the tape have been given the same reference numerals as the layers formed by flowing downwardly on sliding surfaces or extruding from the slot 16, except that reference numerals are indicated by a prime to indicate the thickness of the Layers after application can be different than during the formation of these layers.

ίο The complete device can be made from a single Block made of metal or other material. It is, however, about the making of this To facilitate the device and to enable it to be cleaned when on from a layered material another is passed over, more expediently, the device from a number of individual parts that can be put together and taken apart. That's why it is made up of three separate blocks 23, 25 and 26, which in the assembled state by any suitable, funds not drawn can be held together. If layer materials are used which must be heated or cooled to bring them to a suitable liquid state hold, the blocks may be provided with interconnected tubes 31 and 32 through which a hot or cold liquid medium can circulate. When the tubes 31 at the joint surface are formed by two blocks, a seal 33 can be used to provide the necessary liquid-tightness Connection is guaranteed.

Using a double feeding device of this type, a photographic Gelatin-silver halide emulsion and a protective layer of clear gelatin and some other layer materials well known in the photographic art on different ones simultaneously Types of carriers, including cellulose acetate carriers, at various application speeds applied. All coatings produced were, like tests with from the product after Micro-cross-sections taken completely dry showed, excellent, and those with the Photographic tests carried out on coatings in each case showed that each coating was within the tolerance range was compared to the same product that was applied in the known manner of the individual layers was produced one after the other and in which each layer was completely dried before the next layer was applied.

The device may be provided with any suitable type of adjustable holder, so that the position of the lower end of the sliding surface is set relative to the tape to be coated can be used to get the best results. For this purpose, the device in one Frame 32 'be supported, which is provided with bearings 33' which are concentric on the axis of the roller 13 are pivotably mounted about this axis, so that the position of the device around the roller is changed can be (cf. FIG. 1), whereby it engages in a curved recess 35 of the carrier 36 Clamping screws 34 can be determined in any set position. The device can be mounted pivotably around the circumference of the roller on the frame 32 'for fine adjustment and can be used to adjust to the role to and from

her way slidably attached to the frame by any suitable means not shown be.

After the carrier tape W has been provided with layers, it may be necessary to allow the applied layers to solidify and / or to dry. In the manufacture of photographic films or papers, the coated layers may be of the type which are allowed to solidify by cooling prior to drying in order to limit the amount of relative flux between the layers or between the layer adjacent to the support and the support. In such a case, the tape W after being coated can be passed through a cooling chamber 37 and then through a drying chamber 38. If the applied layers are of the type that do not require cooling prior to drying, the cooling chamber 22 can be omitted or bypassed. The tape can be guided away from the drying chamber 38 by a feed or guide roller 39.

In Fig. Referring now to Figure 3, there is shown a triple feeding device in accordance with the invention which allows three separate layers to be applied simultaneously to the surface of a belt. According to the structure, this is practically the same as the double feeding device according to FIG. 2, but it differs from this in that two exit gaps ending directly at the application point are used in combination with a simple sliding surface feed. This device contains three chambers SO, 51 and 52, into which different layer materials 53, 54 and 55 are pumped through inlet nozzles 56, 57, 58 by means of separate metering pumps P. The sheet material 53 is pushed through an elongated narrow gap 59 which forms it into a layer 40, while the sheet material 54 is pushed through an elongated narrow gap 41 which forms it into a layer 42. The exit gaps 59 and 41 meet at an acute angle, so that the layers 40 and 42 pressed by them are brought into surface contact with one another at the moment in which they emerge from their gaps, and are thus combined into superimposed layers before they are in pass over the drop of layer material 17 'maintained between the mouth lips and the surface of the tape W to be coated.

The sheet material 55 is passed through a substantially horizontal, elongated narrow gap 44 in the form of a narrow band and pressed on the outside on a downwardly inclined sliding surface 45 on which it flows downward under the influence of gravity and forms a smooth, uniformly thick layer 46. the Sliding surface 45 cuts the exit gap 41 at an acute angle approximately at the point at which the Layers 40 and 42 come together so that, as layer 46 moves away from the sliding surface, is united on its surface with the layers 40 and 42 and the three layers in this Pass the combination into the layer material drop without mixing. Once the tape is across and in Touch is moved over the layer material drop 17 ', it takes the three layers 40, 42 and 46 of the different layered materials that are so applied to the surface of the tape in separate layers 40 ', 42' and 46 'are applied. Because the layers already applied differ from those in the drops entering layers 40, 42 and 46 differ in terms of their thickness due to the effect of the drop As explained above, they are denoted in the drawing by reference symbols with ('). As with the previous example, the temperature of the layer materials during their Flow through the device can be controlled by liquid heating or cooling means, if necessary flow in stored tubes 31 '.

ίο While visual examinations of micro-cross-sections of the coated tapes showed that the various layers of laminate did not mix as they passed through the bead of laminate, it was impossible to determine the exact shape of the paths each layer takes through the bead of laminate. It is believed, however, that in the dual device of FIG. 2 the expressed layer L accumulates backwards and fills the space 60 between the lip 61 and the tape W due to capillary action, while the upper layer L, on the lower edge of the sliding surface 21 due to the combined action of capillary action and that of friction generated tension of the band extends upwards. In the case of the triple feeding device of FIG. 3, the upper and lower layers 46 and 40, respectively, are assumed to move in the same manner as the two layers of FIG. 2 cautious. It is believed, however, that the middle layer 42 passes through the drop with virtually no deformation because it does not come into direct contact with the sliding surface 21 or the surface of the belt W and is therefore not under the influence of capillary action.

In Fig. 4 a device built according to an embodiment of the invention is drawn, with the four layers of different layer materials simultaneously in separate layers on the surface a tape can be applied.

This device contains the combination of two sliding surface feeds with two exit slits ending directly at the application point. It contains four chambers 65 to 68, into which 69 to 72, for. B. by separate metering pumps P, four different liquid sheet materials can be introduced continuously at a known rate. The two chambers 67 and 68 are separated from one another by an adjustable partition 73 which is spaced from the top wall 74 so that a gap is formed through which the sheet material introduced into the chamber 67 can be formed into a layer 75. The layer material introduced into the chamber 68 is guided together with the layer 7S into the outlet gap 76 and is thereby formed into a layer 77 between the one surface of the layer 75 and the lower wall of the outlet gap 76. The two layers 75 and 77, united on their surface, pass through the gap 76 and thus merge into the layered material drop 17 "which is maintained between the surface of the belt W and the mouth lip of the device. As in the previous examples Belt supported inwardly by a roller 13 and continuously moved transversely into contact over the drop of sheet material.

The liquid sheet material introduced into the chamber 66 is through a narrow gap in the form of a

The tape is printed outwardly on a downwardly inclined sliding surface 79. This layer material then flows under the influence of gravity, the sliding surfaces move downwards and become smooth and even thick layer 80 is formed. This sliding surface 79 unites with the upper wall of the outlet gap 76 at an acute angle, so that the layer 80 leaving the end of the sliding surface 79 at its surface with the layers 75 and 77 leaving the exit gap 76 just in front of or just in front of it are combined at the point in time at which these layers merge into the layer material droplets 17 ″.

The sheet material introduced into the chamber 65 is passed through an elongated narrow gap 82 in FIG Shape of a band pressed outwards on a downwardly inclined sliding surface 83, which is above the Sliding surface 79 is arranged parallel to her. This layer material forms when under the influence of the A smooth, uniformly thick layer 84 is created on the sliding surface 83 due to the downward movement caused by gravity at the point in time at which it reaches the sliding surface 79. This layer then flows on top of the layer of the sheet material pressed on the sliding surface 79, and the two layers move on the sliding surface 79 together down and in the drop 17 ". From this it can be seen that the four layers 75, 77, 80 and 84 of the individual layer materials just before or just at the point in time at which they pass into the layer material droplets, are united along their surfaces. These four Layers are then picked up from the surface of the tape in exactly this orientation at the same time, without showing any mixing or contamination between the layers. These layers may vary in thickness and speed after application to the tape of the layers entering the layer material drop 17 ″ because of those mentioned above Drop effect may be different. Because of this possibility of diversity in terms of Thickness of the layers after application to the tape, these layers became the same Reference numerals denote like the layers entering the layer material drops, but have been provide these reference numbers with a prime (').

To show the various layers applied to the tape surface it was because of the the minimum size required by the line thickness, the combined layers in one of the relation to the thickness of the carrier tape to which it is applied, which differs from reality are. The thickness of the combined layers of the coating is in contrast to what is shown in the drawing it is more like the same or an estimable fraction of the thickness of the carrier tape on which it is attached be applied. In particular, in the embodiments containing three or more layers, the actual thickness of the combined layers is only a small fraction of the total thickness of the carrier tape. As a practical example of an exaggerated one Tape, for the treatment of which this device is very well suited, a color film is considered. Which in this case possibly consists of a cellulose acetate carrier tape a thickness of 0.076 to 0.2 mm. The thickness of each of the three color sensitive emulsion layers can be in the dried state vary between 0.0025 and 0.025 mm, the protective layer or Protective layers separating the various emulsion layers can be approximately 1 micron thick. The application device described is particularly suitable for applying such thin layers, and it was observed that even four of the thickest layers applied to the tape the total thickness of the four layers was less than one tenth the thickness of the tape itself.

ίο It cannot be explained why two or more Layers of layered material move simultaneously in accordance with the invention Do not mix the application on a tape, but rather as layers so clearly separated and so free from mixing and contamination at the interface of the layers remain as if the same Materials with each layer completely dry before applying the next layer were applied one after the other. This is not based on the fact that the different layer materials are physically or chemically immiscible with one another because, as the examples show, the same results can be obtained if all layer materials are connected to each other both physically and are chemically identical, with the exception that one of them contains a dye or carbon dispersion was stored in order to obtain visible evidence of this phenomenon.

When trying to explore the reasons why the different layers of the layer materials do not mix when raised in accordance with the present invention, the question became investigates whether this case of the form of motion known as "laminar flow" is a viscous one Fluid depends on the form of motion known as "turbulent flow" differs. According to Reynolds theory of fluid flows (R. C. Binder, »Fluid Mechanics ”, Prentice Hall, 1943, p. 71) become two separate layers flowing through a tube Water, provided there is a laminar flow, remain separate as long as the critical one Speed is not yet reached, and after the critical speed is reached, will the flow will become turbulent and the flows will mix. Reynold showed that the critical one Velocity from the diameter of the tube, from the speed of the liquids through this tube, depends on their density, their viscosity and that if these four factors work in one and only one way are combined to give the function known as Reynolds number, which is the critical speed indicates the flow of a liquid through the tube. While this theory is under the assumption that the flow is laminar because, according to Reynolds number, the critical velocity has not yet been reached, can be used to explain why the separated Layers when going through in a united form through the exit gap in one of the described Do not mix device types, this theory does not appear to be applicable for layers that are in Connection of an exit gap to be formed with a sliding surface; and explains this theory nor why the separation of the layers through the layer material drop after application on the tape is sustained because the layers do not move through a tube

609 509/178

move through and are not completely limited in any way. The only explanation for this phenomenon, which seems justifiable, is that it is normally an estimable time takes to mix two solutions even when brought together in such a way that turbulence arises. In the present method of making the coatings the different layers are not united for so long before they are applied to the tape, that noticeable mixing can occur, even if the flow conditions are such as to promote such a mixture. Why the layers of a coating their separation between the time they are applied to the tape and the time, too that they are completely dry is inexplicable, except in the case of layered materials can be used, which can be obtained by cooling, heating or by chemical action directly allowed to solidify after application to the tape surface and before drying. Here again, time can be the critical factor, since the time span between the application of the layers on the tape and the point in time, in which the coating has dried is relatively short and perhaps less than the length of time which is necessary so that the layers or the substances dispersed in them diffuse into one another.

Claims (4)

Patent claims: 1. Device for the simultaneous application of several layers of liquid layer materials onto a layer carrier tape that is continuously guided past the application site for production multilayer photographic recording materials according to that disclosed in patent 1151173 described method, characterized by several, each with a gap-shaped outlet channel provided liquid chambers, the outlet channels partly directly in front of the guideway of the carrier tape to be coated at a distance slightly exceeding its thickness end, partly open into an inclined sliding surface (21) attached above the application site, and characterized by pumping devices (P), which the layer materials continuously in a the desired layer thickness corresponding amount through the chambers and their outlet channels, so that this is under the influence gravity flowing over the inclined surface in the form of a thin strip of layer material lies over the layer tape emerging immediately in front of the guideway and together with this is taken up by the carrier tape guided past the application point. 2. Apparatus according to claim 1, characterized by two chambers (15, 18), wherein the Outlet channel (16) of one chamber immediately in front of the guideway of the one to be coated The carrier tape ends in a distance slightly exceeding its thickness and the outlet channel (20) of the other chamber opens into the sliding surface (21) attached above the application site. 3. Apparatus according to claim 1, characterized by three chambers (SO, 51, 52), wherein the outlet channels (42, 44) of two chambers are arranged according to claim 2, the outlet channel (59) of the third chamber (50) at an acute angle in the immediately before the one to be coated The outlet channel (42) ends at the end of the carrier tape. 4. Apparatus according to claim 1, characterized by four chambers (65, 66, 67, 68), of which two (67, 68) from one attached in a lower part, through a height-adjustable Partition wall (73) divided recess are formed, wherein the partition wall of one of the recess upwardly covering surface (74) has a distance such that a gap is formed, from the one chamber (67) through the other chamber (68) and its outlet gap (75) in a common outlet channel (77) opens, which opens directly in front of the guideway of the coating carrier tape ends in a spacing slightly exceeding its thickness, while the exit gaps of the two remaining chambers (65, 66) arranged one above the other into one The inclined sliding surface opening above the application site. Considered publications:
German Patent No. 891190;
U.S. Patent No. 2,681,294. 1 sheet of drawings 609 509/178 2.66 © Bundesdruckerei Berlin