DE7402360U - DEVICE FOR THE SIMULTANEOUS APPLICATION OF AT LEAST TWO COATINGS OF LIQUID COATING MATERIALS ON A SURFACE OF A GOOD, IN PARTICULAR A TAPE - Google Patents

Description

· ■ ·;. ·. . ■ · .. ;;. ··;: · ;: PATENTANWÄLTE

'··' Dr.-lng. Wolff t

H. Bartels. L.

Dipl.-Chem. Dr. Brandes | Dr.-lng. Hero f

Dipl.-Phys. Wolff {

D-7 Stuttgart 1, Lange Strasse 51 f

Tel. (0711) 29 6310 U. 29 72 95 \

Telex 07 22312 (patwo d) |>

Telegram address: | tlxO7 22312 wollf Stuttgart

PA Dr. Brandes: Headquarters Munich Post office check. Stuttgart 7211-700

Bank code 600 100 70

Deutsche Bank AG, 14/286 30

Bank code 600 700 70

Office hours:

9-11.30 a.m., 1.30 p.m.-4 p.m.

except saturdays

G 74 02 360.2 August 29, 1977

Our ref .: 124 237/487375 kdk

Eastman Kodak Company, Rochester, New York State,
United States of America

Device for the simultaneous application of at least two
Layers of liquid coating materials on top of a
Surface of an item, in particular a strip

Telephone information and Orders are only accepted according to iichrlltllctW Confirmation binding? '■

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The invention relates to a device for simultaneous Applying at least two layers of liquid coating materials on a surface of an item, in particular a belt, with a sliding surface sloping downwards, over the at least one layer of the coating material flows down before it is coated onto the material with an outlet opening located at the upper end of the sliding surface for the supply of coating material to the sliding surface and with one arranged at the lower enda of the sliding surface Device for moving the material up to the coating material brought in via the sliding surface with transversely to the direction of flow and upward direction of movement, this means being arranged so that between the lower edge of the inclined surface and the upward one moving material to be coated a substantially horizontal gap is formed, which is a bead of the coating material bridged.

Devices of the above type are already known from German patents 1,216,686 and 1,151,173. These known devices can be used to v / earth the material to be coated, which is, for example a tape of photographic film material is provided with an emulsion layer or with several emulsion layers at the same time by using a coating head which has one or more inclined sliding surfaces over which a liquid coating material or several liquid coating materials are allowed to flow down prior to applying this coating material or materials can flow into a liquid bridge or a liquid bead that leaves a small gap between

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see the Boschichtungkoof and the one closely adjacent to it Well bridged. TI ei such devices is ea too known, an extruder sliding surface coating head to provide the one or more sliding surfaces has at least one extruder outlet opening the coating material directly into the liquid bead is extrudable into it.

The sliding surface part of the coating head can have an outlet slot or several separate outlet slots, through which a coating material or several coating materials can be supplied in metered quantities from the associated feed devices and distributed evenly on the associated inclined sliding surfaces. The iodine of the coating materials flies downward as a liquid layer over the inclined sliding surface under the influence of gravity, the liquid layers smoothing out and assuming a uniform layer thickness. If more than one sliding surface is provided, these are arranged in such a way that the layers of liquid, lying on top of one another, flow over the sliding surfaces. At the end of the last or lowermost sliding surface, ie that of the E: -: truder outlet or the sliding surface closest to the extruder outlet, the layer leaving this sliding surface flows or the layers admitting this sliding surface flow onto the bead of liquid flowing through the the extruder outlet opening of the coating material extruded coating material is formed. Thus da3 flows over the sliding surface part. 1 dos coating head it via the Glt. '. T-surface part brought up Beschichtungsrnaterialion on the liquid bead of time, so that <\ nz moving, located zoom out or coating material to flow into contact with the bead? At the same time, all liquid layers GN, i.e. both those of the extruder

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Toil as well as the observation materials brought up from the sliding surface part of the coating head, which are deposited on the material in the form of a composite coating of essentially discrete, superimposed overlaying layers. \

In the known devices, the coating head of which only has a sliding surface part, but not an additional extruder part has several shortcomings. It can be with the known Devices namely defects in the coating layer occur when the bead is disturbed. A particularly noticeable error is the occurrence, for example longitudinal scratches or notches which make it completely impossible to identify the coated tape in question as photographic To put the product on the market. The occurrence of these longitudinal defects increases rapidly when the "feed speed of the 3and to be coated" is increased.

In such devices it is also advantageous to have a pressure difference between the two free surfaces of the bead, for example by applying a negative pressure in the endeavor on the rear surface of the bead generated to prevent excessive vibration and / or tearing of the bead. Of course, the level of the negative pressure is which can be used is limited, because if the negative pressure level is too high, the strong contact with the bead Pressure difference can be the cause of a malfunction and / or tearing of the bead. Occasionally it can also come that the strength of the vacuum applied is not high enough to cause excessive vibrations in the

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To switch bead off and it is therefore necessary, the Increase negative pressure. If, however, an increase in the negative pressure itself is a disruption and / or tearing of the bead caused, one is in many cases forced to change the coating conditions, Indian one in a disadvantageous way about the speed of advance of the tape is reduced if you want to achieve satisfactory coatings.

Another problem that arises when using the known devices of this type is that particles, that occur in the liquid coating material, accumulate on the (coating head on the edge facing the tape and cause undesirable streaking or streaking in the coating applied to the tape can.

The invention is based on the object of creating a device of the type in question which makes it possible, in particular Apply layers free of imperfections at a high working speed.

In a device of the type mentioned, this object is achieved according to the invention in that a besides the Sliding surface for a first coating material at least one extruder outlet opening for a second coating material having extruder sliding surface coating head is provided, the sliding surface at its lower end in a bent, less than the horizontal strongly inclined end section passes over, and that this bent end section of the sliding surface above the extruder outlet opening is arranged, which is closely adjacent to the material to be coated, so that the out of the extruder outlet opening extruded second coating material forms the gap between the same and the material bridging liquid bead on which the over the end portion of the Sliding surface flowing first coating material flows up.

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By the inventive cor.ib! Nation of an extruder outlet opening with an end section of a sliding surface arranged above the same and opposite the horizontal has a lower inclination than the sliding surface, the possibility is created, in an advantageous manner, multi-layer To produce coatings at a higher operating speed, al3 this in known devices of this type is possible, while at the same time flawless coatings of improved quality are achieved.

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The invention is illustrated below with reference to etne3 in the drawing illustrated AusfUhrungsbeispiels explained in detail.

Show it:

Fig. 1 is a partially cut and broken off Drawn side view of a coating device of the usual type and

FIG. 2 is a view similar to FIG. 1 Device according to an embodiment of the invention, wherein the aborted and cut drawn, closest to the coating roller Part of the coating head compared to the coating roller and to the remaining parts of the coating head is exaggerated.

Fig. 1 shows a known loading device of the Kind as shown in German patent specification 1,211,438 is. In such a device, a good, in the example shown a belt W, is driven by a device Coating roller 13 carried and attached to a coating head 10 moved past. The tape can consist of paper, metal or a plastic film and can already have a or have several, essentially dry, previously applied layers. The coating head For the sake of clarity, FIG. 10 is shown here in an embodiment which is used to simultaneously apply two coats to the band W. To the-

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For this purpose, two metering pumps P and P 'are connected to associated storage devices for liquid coating materials 16 and 23, respectively, and supply these coating materials 16, 23 in desired quantities to associated cavities 11, 19 which are formed in the interior of the coating head 10. The Beschxchtungsraaterialien 16, 23 v / earths put under pressure so that they flow as a liquid band through narrow outlet slots 14 and 21, which open at one end into the associated cavity 11 and 19 and at their other end in a slot opening 15 or 22 ends. The outlet slots 14, 21 are each delimited by two flat surfaces 14 ', 14 "and 21', 21" which lie opposite one another and run parallel to one another at a small distance from one another. The belt V / is held by the coating roller 13 at a close distance from the slot opening 22, so that an extruded bridge or a bead of the coating material 23 can be formed which forms the gap between the slot opening 22 and the surface of the coating material to be coated Band W spanned. The slot opening 15 of the outlet slot 14 is arranged at the upper end of a flat sliding surface 12 that slopes downwards. The layering material can flow down this flat sliding surface so that the layering material is smoothed and assumes a uniform layer thickness. The lower transverse edge of the sliding surface 12 is closely adjacent to the slot opening 22 of the outlet slot 21, and the sliding surface 12 is inclined relative to the outlet slot 21 at an acute angle. Wrnn the liquid • jchLcht dos Be.'jchichtungsn.iterials Eat vnrl'ißt the lower edge of the sliding surface 12, flows si "in cli" Flüssigkn Lt5brücke or (lon Flüssigkeitswulrst and both 'ioachich tungsmaterinlion 16 and 2 3' - / orcipn from which in w'vioritlichon upward b'rver / pnden Dand VJ is taken up, while di <? 3e :; nit high? r Vornchubq ^ qchv / lndigkeit nn dsn

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Bead is moved past. The coating materials 16, 2 3 are deposited on the facing surface of the strip λ 'as a composite coating of essentially discrete layers on top of each other. As "yourself moving upward "are all those locations on the band W in which the vertical component the speed is greater in magnitude than the horizontal speed coraponent.

To stabilize the ßrücke or the bead, a Suction or a negative pressure is applied to a rear surface of the bead so that a pressure difference between the both free surfaces of the bead is generated. The negative pressure can be generated by means of a chamber 25, which is connected to a suction pump P ″, 28 which draws air from the chamber 25.

In Fig. 2, a portion of an improved extruder slide surface coating head 30 of the type to be described here is shown. For the sake of clarity and clarity, no suction chamber is shown in the illustration of FIG. 2, such a device for generating a | Pressure difference is, however, in connection with the training guide for i in FIG. 2 is advantageous. The coating \ processing head 30 is gezeig- in many respects in FIG. 1 | The coating head is similar, but differs from this in that the coating head 30 has a rigid j

ren, upwardly bent end portion 31, which '■■ adjoins the lower end of a sliding surface 3 2 at an obtuse angle 38 and against the surface I

those to be coated move essentially upwards moving goods3, in which it is

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showed example of a tape : Ί is. The end section 31 is preferably flat, has the same width measured in the transverse direction as the flat sliding surface 32 and ends in a transverse edge 34, which is formed by the flat surface of the end section 31 and a side surface 39 of an extruder outlet opening 41 will. Bai the manufacture of the end section

31, it is advantageous at the obtuse angle 3 8 between the surface of the end section 31 and the sliding surface

32 to provide a rounding, as shown in FIG.

The extruder outlet opening 41 is arranged at a substantially horizontal distance from a coating roller, which is slightly greater than the thickness of the tape W that is to be coated, so that when the coating head is in operation, an extruded bridge or an extruded bead of liquid coating material 4 3 d.the gap between the coating head and the surface of the tape W bridged. The width of the gap between the outlet opening 41 and the surface of the strip to be coated is preferably between approximately 0.13 mm and 0.76 mm. As can be seen from Fig. 2, after it has been pressed out of a cavity 46 and through a narrow metering slot 47, liquid coating material 36 flows downwardly on the sliding surface 32 and then along the essentially horizontally extending rigid end portion 31 into the bead of the coating materials. The sliding surface 32 is inclined with respect to the horizontal at a desired angle, which is preferably greater than 10 and less than 45 °, depending on the properties of the liquid coating material to be applied. Since the end section 31 has a smaller inclination with respect to the horizontal than the sliding surface 32, the layer of fleece material flows

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36 over the l'ndo section 3.1 with reduced flow velocity, yes,! Och increased layer thickness (Tioiv?). The increased layer thickness on the bent end sucker i. i: .t 31 is an advantage, '.' / because the interfering effects, which -vrgsben, if particles should stick to the edge 34, weakened by the greater thickness of the layer at the bent end part 31 '.- / earth. That is to say, a particle of a certain size / that has settled on the edge 34 produces a greater disturbance in a thinner (shallow) liquid layer, whereas a thick (deep) liquid layer flowing past the particle is less disturbed. The end portion 31 has a substantially horizontal direction and is preferably exactly horizontal. The end section can, however, also be inclined at an angle relative to the horizontal in the direction of flow of the liquid stream, which is preferably in the range of ~ 5. The length of the end section ta "? 1, measured in the direction of flow, is approximately in the range from approximately 0.5 mm to 2.1 nr.1 and is preferably approximately 1 mm. Such dimensions are advantageous when coating photographic coating materials, the occurrences in the rail thickness in the dry state vary between 0.0025 min and 0.025 mm and with protective layers separating such emulsion layers from one another having a thickness of the order of 1 micron.

Bsi using the Oeschi ca processing roller 33 for storing the tape in a smooth state, it is desirable that the studs of the application of the liquid; Bead or Flüsöigkcitsbrücke M to the tape within a preferred range of acute angle "mooring" located int. In this preferred range, or is, is the area of. about 40 ° below the v / aa just η Uadius dar Deschichtungnwcilze 3 3 to about 30 above the horizontal radius. That the Gnalt is essentially horizontal

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has the advantage that the force of gravity acts on the hanging bridge of the liquid coating materials and can facilitate the formation of the bridge or bead.

In the prior art device shown in Figure 1, there is one factor which can contribute to making the bead more fluid Coating materials are occasionally unable to withstand higher pressure differentials, in which that this bead is in addition to that on him

attacking pressure difference itself against the force support nut, which exercises the downward-shooting liquid layer (s), which continuously the Bead is (are) fed. The supply taking place along the essentially horizontal plane of the end section 31 of coating material to the bead, as can be seen is capable of reducing the force of the liquid shooting into the bead or otherwise to improve the stability of the bead, so that higher negative pressures at increased coating speeds can be applied to the bead without the bead being disturbed, resulting in unsatisfactory coating results would result. In addition, when using the device shown here, without increasing the The strength of the negative pressure applied achieves higher coating speeds than with the known such devices are possible.

In order to show the advantages of the device described here, two superimposed layers of coatings produced v / earth, in one case a device of the type described here Kind is brought to the application, as shown in Fig. 2. The underneath layer of liquid coating

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tung3materials can have a viscosity of 350 centipoise and as a layer, an applied weight in the wet state of 0.308

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kg / 9.202 m (0.6-3 lha / 100 square feet). The top layer of liquid coating material can have a viscosity of 350 centipoise and, when wet, a coating weight of 1.27 kg / 9.2902 m ² (2.8 lbs / 100 square feet). A negative pressure can be maintained at the liquid bead during the coating process, the gap between the extruder outlet opening 41 and the belt W being approximately 0.25 mm (0.010 inches. It has been found that streaking occurs when the apparatus described here is operated due to an instability of the bead, as occurred during the operation of the known device, could not be observed even at a high coating speed.

The invention can also be used with other extruder slide surface coating heads can be realized as described here. For example, the extruder part of the coating head have more than one extruder outlet opening, as for example in the already mentioned German Patent 1 211 488 is shown. The coating head can also have more than one sliding surface on iron, the sliding surfaces being arranged one above the other, see above that each of the two or more liquid layers formed over the respective associated with these layers Sliding surfaces flow before the relevant layers flow onto one another and overflow over the lowermost sliding surface and the upwardly bent end section lying one above the other. An example of a coating head of this last-mentioned type, which is also shown here Way can be improved, is also in the aforementioned German Patent 1 211 433 (see Fig. 4 there) shown.

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j The device described here can be used for coating

^ any substances or mixtures of substances used

: v / ground in the liquid state by bead coating

J can be applied, for example in the form of a

Solution, a dispersion or a suspension. Multiple If the coating material is a mass with an organic carrier liquid, there are also other carrier liquids into consideration, for example inorganic or aqueous carrier liquids or

Γ natural substances. The individual layers can consist of the same or different liquid coating materials, and these coating materials can

ΐ be mixable or indelible with each other. High viscosity

polymer layers can with the device described

be coated with advantage by aqueous or organic Carrier liquids are applied.

Except for the production of photographic materials, the apparatus described herein can be used in any other Areas of coating technology are used when one or more separate layers of different coating materials coated v / should be grounded in order to

: (to ver. specific desired properties of a product

Rent.

The device described here is particularly suitable

* for multi-layer coating in cases where it is desired,

that the upper layer has a relatively high coverage (layer weight per m layer area) compared to that having lower layer.

The invention has been described above with reference to a preferred Ausführungsbeispie .. explained in detail. It ver

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it is clear, however, that modifications and developments can be made without departing from the scope of the invention to leave.

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Claims (7)

• I I f «· · * if «« .pi »·« · * Protection claims Device »for the simultaneous application of at least two layers of liquid coating materials to a surface of an item, in particular a belt, with a downward sloping sliding surface over which at least one layer of the coating material flows down before it is coated onto the item, with one at the upper end The outlet opening located on the sliding surface for the supply of coating material to the sliding surface and with / a device arranged at the lower end of the sliding surface for moving the material to the coating material brought over the sliding surface with a direction of movement transverse to the direction of flow and upwards, this device being arranged in this way is that a substantially horizontal gap is formed between the end edge of the inclined surface and the upward moving ^ material to be coated, which is bridged by a bead of the coating material, characterized in that an outside the sliding surface (32) is provided for a first coating material (36) at least one extruder outlet opening (41) for a second coating material (43) having extruder sliding surface coating head (30), the sliding surface (32) at its lower end in a The bent end section (31), which is less inclined to the horizontal, merges, and that this bent end section (31) of the sliding surface (32) is arranged above the extruder outlet opening (41) which is closely adjacent to the material (W) to be coated, so that the second coating material (43) extruded from the extruder outlet opening (41) forms the liquid bead bridging the gap between the same and the material (W), onto which the first coating material (32) flowing over the end section (31) of the sliding surface (32) 3 (5) flows up. 74Q2360 12/29/77 1 * 4 * - Hi - 2. Apparatus according to claim 1, characterized in: that the lungs of Undabachnitta (31), measured in Äichtui.g Liquid flow, is between 0.6 mn and 2.1 mm. 3. Apparatus according to claim 1 or 2, characterized in that the end portion (Tl) has aine ivx substantially horizontal and substantially above surface. 4. Apparatus according to claim 3, characterized in that the end portion (31) in the direction of the liquid flow has an angle of inclination in the range of -5 relative to the horizontal. 5. Device according to one of claims 1 to 4, characterized in that that the above the '.' "guide surface (32) arranged Exit opening for the first Boschichtunysmaterial (36) an associated narrow '/ iuia & ßachlitz (47) for the metered Approach of the sliding surface (32) to be fed Coating material (36) and that the Suneßschlitz (47) with a cavity (46) for the Aufηahne of the first coating material to be fed to the Jlumeßschlitz (4 7) (36) is in connection. 6. Device according to one of claims 1 to 5, characterized in that as a device sum moving the 1ut3 (W) a substantially horizontally extending 3esc: iichtungwalze (33) is provided, of the circumference of at least a part of the good (Vl ) is wrapped around, and that the end section (31) of the sliding surface (32) is arranged relative to the clut (Vi) wrapping around the coating roll (33) so that the first and second coating material (36 uz.; 43) on this rn a G toi In upr, 'o met where rc? on ,, •; 3.ic ^: > in an area between ungof'ihr ^ O below the horizontal t'iadiur. lor rjeschichfcungswalzp (33) and -mgefiihr 30 lies above their horizontal radius. 7402360 12/29/77 7. Device according to one of claims 1 to 6, characterized in that that the sliding surface (32) with its lind section (31) forms a coherent body. 7402360 12/29/77