EP2755774A1

EP2755774A1 - Metering coater for highly viscous coating compositions

Info

Publication number: EP2755774A1
Application number: EP12772080.3A
Authority: EP
Inventors: Ludwig Grader; Mustafa Ay
Original assignee: Acino AG
Current assignee: Bayer Pharma AG
Priority date: 2011-09-13
Filing date: 2012-09-11
Publication date: 2014-07-23
Anticipated expiration: 2032-09-11
Also published as: SI2755774T1; RS54836B1; PT2755774E; WO2013037776A1; HUE029180T2; ES2575708T3; DK2755774T3; HRP20160620T1; PL2755774T3; DE102011082630A1; EP2755774B1

Abstract

The invention relates to a method for producing transdermal therapeutic systems (TTS), and to a coating head used in said method and comprising a tubular distribution chamber (1) which extends from an inlet opening (4) to an outlet opening (5), and a supply gap (2) which is attached laterally to, and at least along one part of the length of, the distribution chamber (1) that is arranged in the interior of said coating head (10), said gap extending from the distribution chamber (1) to a surface (6) of the coating head (10) so as to form an opening of said distribution chamber to the surface (6). The cross-section of this supply gap (2) varies along the length of the gap.

Description

Knife pourer for high-viscosity coating materials

The present invention relates to applicators for the continuous application of viscous coating compositions on film webs and in particular to a coater for producing coatings with uniform layer thicknesses.

Coating units for the continuous coating of film webs with viscous coating compositions generally comprise an area where a coating composition of a so-called foundry is applied to the film web in a defined dosage. Depending on the coating task or formulation of the coating composition, different foundries, such as e.g. Extrusion foundries, Pflatschgießer, Streichrakelgießer, Anspülgießer, roller or Walzengießer or Schlitzgießer, and of which in particular knife pourers, for use. As Schlitzgießer foundries are generally referred to, in which the coating material exits through a slit-shaped gap from the casting head. The slot-shaped gap connects a distribution chamber formed in the interior of the casting head and provided with an inlet to the outside of the casting head and serves for the defined supply of a coating material from the distribution chamber to the surface of the casting head. In knife pourers, moreover, the distribution chamber is connected to a drain different from the slot-shaped feed gap, whereby more coating mass flows through the distribution chamber than exits via the feed gap.

Coatings for the preparation of drug depots for transdermal therapeutic systems (TTS) require a particularly uniform coating order, as this, in addition to a homogeneous Wirkstoffver- division in the coating composition is a prerequisite for a targeted dosage of transdermally administered active ingredients. Knife pourers enable a precisely metered, even application of coating compositions to film webs and are therefore frequently used for the production of drug depots for transdermal therapeutic systems.

Knife pourers have, as a core element, a pouring head with a tubular distribution chamber arranged in the interior, which is open along its length via a slot-shaped gap to one side of the pouring head. For coating, the distribution chamber is flowed through by the coating compound or the coating material in standard knife pourers, the coating chamber being supplied with the coating composition for this purpose at an end designed as an inlet and being discharged via the other end formed as a drain. The pressure of the coating composition in the distribution chamber is higher than the ambient pressure of the casting head, so that part of the coating material supplied via the inlet is guided via the slot-shaped gap to the outside of the casting head. The coating compound emerging from the casting head via this feed gap wets the film web which is guided along adjacent thereto, so that it is carried along by it and forms a layer of coating material thereon as a consequence. The length of the feed gap determines the width of the coating layer applied to the film.

The thickness of a coating layer applied as described is essentially determined by the flow of the coating material through the feed gap, the gap between the feed nip and the film web, the viscosity of the coating material and the speed of the film web relative to the feed nip. The flow of the coating material through the feed gap is itself a function of that prevailing in the distribution chamber

Pressure as well as the height and width of the feed gap. An analytical determination of the parameters required for a given coating thickness is possible in principle, but is supplemented or replaced in practice by an experimental determination, often taking empirical values.

A uniform coating thickness across the width of the film web requires a uniform material flow of the coating material over the length of the feed gap. This is given when the pressure drop along the flow direction of the distribution chamber is negligible. Provided the same flow rate of the coating composition in the distribution chamber, the pressure drop between inlet and outlet of the distribution chamber is a function of the distance between inlet and outlet and the viscosity of the coating material. The higher the viscosity of the coating material or the greater the distance between inlet and outlet of the distribution chamber, the greater the pressure difference. It has been shown that the pressure drop in the coating widths currently used for the production of transdermal therapeutic systems of currently up to 1500 mm in conjunction with the new active substance-containing coating compositions used therewith having viscosities in the range of about 500 to about 5000 mPas no longer is negligible and leads to changes in the coating thickness across the width of the film web, which are outside the tolerances to be maintained.

A reduction in the layer thickness variation caused by the pressure drop along the longitudinal direction of the distribution chamber can be achieved by pointing to the inlet of the distribution chamber End of the feed gap is arranged closer to the film web than the end of the supply gap facing the end of the distribution chamber. However, a compensation of the layer thickness variation by a correspondingly inclined alignment of a Meßergießers is only to a small extent possible, in particular because the pressure along the distribution chamber does not decrease linearly and thus also the introduced from the distribution chamber in the feed gap flux of the coating composition varies non-linearly along the length of the casting head ,

In order to reduce a variation of the coating thickness caused by the pressure drop in the distribution chamber, it is also possible to produce a plurality of coating material streams in the distribution chamber. For example, the coating composition can be fed centrally to the distribution chamber and then discharged at its two front ends. The reverse case with a feed on both sides and a central discharge of the coating mass is also possible. Since each partial flow of the coating material in such Mehrstromgießköpfen covers only half the distance, the pressure drops in the distribution chamber are reduced to half. By using multiple inlets and outlets, the pressure drops along the length of the distribution chamber can be further reduced. However, such constructions are not only very expensive to manufacture, but in use require an exact coordination of the individual partial flows. In addition, variations in the coating thickness with multi-flow casting heads can indeed be reduced, but not completely avoided due to the reduced but nevertheless always present pressure drops in the distribution chamber.

It is therefore desirable to specify knife pourers which enable a uniform coating of film webs by simple means. Furthermore, it is desirable to provide a pouring head that can be manufactured inexpensively. It is also desirable to specify a pouring head whose slot width can be varied as a function of the coating mass. Furthermore, it is desirable to provide a casting head, which can be cleaned easily and inexpensively and thus can be used for different coating compositions. It is also desirable to specify a casting head in which the length of the feed gap and thus the width of the coating layer applied to a film can be varied in a simple manner.

Embodiments of corresponding knife pourers comprise a pouring head with a tubular distribution chamber extending from at least one inlet opening to at least one drain opening and a feed gap which laterally adjoins the distribution chamber arranged at least along part of the length of the distribution chamber arranged in the interior of the pouring head. The feed gap extends to form an opening of the distribution chamber to a surface of the casting head from the distribution chamber to this surface, wherein the cross section of the feed gap varies along the length of the feed gap.

In embodiments of corresponding casting heads, the at least one inlet opening, the at least one drain opening and the distribution chamber are arranged so that substantially no dead zones can form. The term "dead zones" here are areas in the distribution chamber to understand that are not flowed through during operation of the casting head of the coating material or not so that they are part of the directed from the inlet opening to the drain port and the feed main flow Are to be considered coating. The term "substantially no dead zones" is to be understood as meaning that the volume of possibly existing dead zones, for example in the area around an inlet and outlet opening, is so small that they do not lead to the formation of deposits of the coating composition and the main flow of the coating composition is not negative affect. In embodiments, between the inflow-side end of the distribution chamber and the inlet opening and / or the outlet-side end of the distribution chamber and the discharge opening, a part of the distribution chamber located outside the part of the distribution chamber connecting the discharge opening and the inlet opening is arranged, whose extent in which the discharge opening and the Inlet opening connecting direction is a maximum of 5 mm.

The pouring heads may also be designed such that the inlet opening, the outlet opening and the distribution chamber are arranged such that a coating material emerging from the outlet opening has the pouring head flowing through in a substantially U-shaped manner. The term "U-shaped" here is an at least approximately planar geometry in which a straight or curved leg region connects to each of the two ends of a straight or curved middle region, both leg regions extending from the central element to the same side extend away.

Embodiments of the casting head may include two non-identical plates and optionally at least one intermediate shim foil. The term "plate" here is to be understood to mean a planar, in a first approximation, flat component whose thickness dimensions are substantially smaller than its dimensions transversely to the thickness direction. However, the thickness of the plate may, for example, due to formed in the plate recesses or due to projections on different places of the plate be different. Shim foil is a thin, flat-shaped object to be understood, which is used as an intermediate layer.

In embodiments of the casting head, one of the two plates comprises neither a drain opening nor an inlet opening, so that both openings are formed on the other of the two plates and thus results in a particularly simple and easy-to-clean construction of the casting head.

In embodiments of respective casting heads, the variation of the cross-section of the feed gap is preferably formed as a variation of the height-to-width ratio of the feed gap along its longitudinal direction, whereby a flow resistance varying with respect to the longitudinal direction of the feed gap is achieved.

Embodiments of such embodiments advantageously have a constant width of the feed gap and a varying along the longitudinal direction of the feed gap height of the feed gap, whereby the feed gap can be made particularly simple. Preferred embodiments thereof have a progression shape of the height of the feed gap which decreases in the direction of the flow of the distribution chamber, whereby the pressure drop in the distribution chamber can be compensated in a simple manner.

Solutions of the above problems comprise a plate partially covered with a shim foil for producing a casting head as previously described, wherein both the shim foil and the plate each have an inlet opening and a drain opening, and wherein the arrangement of the shim foil and said openings enables the production of a casting head whose feed gap is a high he has, which has a decreasing in the direction of the flow of the distribution chamber shape.

Solutions of the above problems further comprise a plate partially covered with a shim foil for producing a casting head as described above, wherein the plate has an elongated depression for forming the distribution chamber, and wherein the depression and the shim foil are arranged such that after the casting head has been produced a supply gap can be formed, the height of which has a decreasing in the direction of the flow of the distribution chamber shape. An "elongated depression" here is to be understood as a recess which does not form an opening connecting the two main side surfaces of the plate and whose longitudinal extent is substantially greater than its width extension.

Solutions of the above problems further comprise a plate partially covered with a shim foil as aforesaid or a two non-identical plates and optionally at least one intermediate shim foil, wherein the shim foil has a thickness of less than 3 mm, preferably less than 2 mm and most preferably less than 1 mm.

Solutions to the above problems also comprise a plate partially covered with a shim foil or a non-identical plate as previously indicated and optionally at least one intermediate shim foil, wherein the shim foil is suitable for the manufacture of transdermal therapeutic systems (TTS) Solvent is insoluble and the solvent is preferably heptane. Under "one for the production of transdermal therapeutic sys- Temen (TTS) suitable solvents "are all solvents that are suitable for dissolving the matrix material used in each case for the formation of a TTS, and whose remaining in the matrix material on completion of a TTS residual amounts in users cause no significant skin irritation.

Solutions of the above problems also include a casting head having a partially covered with a shim foil plate with openings formed therein for the inlet and outlet of coating material.

Other embodiments of embodiments of casting heads as described above advantageously have a constant height of the feed gap at a width of the feed gap varying along the longitudinal direction of the feed gap, whereby the width of the feed gap can also change along the direction pointing from the distribution chamber to the surface of the pouring head. Such Zufuhrspaltgeometrien are by conventional material removal methods such. B. milling easy to produce. In this case, the width of the feed gap preferably has a progression shape which increases in the direction of the outlet of the distribution chamber. In specific embodiments thereof, the width of the feed gap on the surface of the casting head is constant and widens, possibly apart from the inlet end of the feed gap, both towards the distribution chamber and toward the downstream end of the feed gap. Such a geometry allows a variation of the flow resistance along the feed gap without altering the wetting conditions along the discharge opening of the feed gap. To compensate for a non-linear pressure drop in the distribution chamber, preferred embodiments have a non-linear characteristic of the shape of the height-to-width ratio of the supply nip. Preferably, such a nonlinear characteristic is determined using a calculation according to a mathematical model of the fluid mechanics of a coating material in the casting head, whereby experimental determinations can be used. Alternatively, the non-linear characteristic is determined purely experimentally.

In embodiments, the casting head comprises two non-identical plates and an intermediate shim foil, the width of the feed gap being determined by the dimensions of the shim foil. The term "dimension" of the shim foil is to be understood here as meaning its thickness extent, which can assume different values at different points, for example in order to realize a supply gap width varying in the longitudinal direction and / or height direction of the feed gap.

In further embodiments of the casting head, the at least one inlet opening and / or the at least one drain opening and / or the at least one tubular distribution chamber and / or the feed gap is at least partially filled with an active substance-containing coating material.

Solutions of the above problems further comprise a device comprising a casting head as described above, wherein the drain opening is connected to a collecting container so that the coating material emerging from the drainage opening can pass into said collecting container. Solutions of the above problems further include a method for uniform application of a non-Newtonian coating composition to a film web, wherein a casting head as described above is flowed through during the coating process with the non-Newtonian coating composition. A "non-Newtonian coating composition" is to be understood as meaning a liquid fluid which has a behavior deviating from that of a Newtonian fluid, ie a fluid with a linear, inelastic flow behavior, in which the shear rate is proportional to the shear stress.

In embodiments of the method, the non-Newtonian coating composition is an active ingredient-containing composition for the preparation of transdermal therapeutic systems (TTS).

When using a casting head with a shim foil, the method of varying the width of the feed channel along its longitudinal extent may include a step of applying compressive forces varying along the longitudinal extent of the feed channel to the shim foil.

Solutions of the above problems also include the use of a pouring head as described above in the production of transdermal therapeutic systems (TTS).

Further features of the invention will become apparent from the following description of embodiments in conjunction with the claims and the accompanying drawings. It should be noted that the invention is not limited to the embodiments of the described embodiments, but is determined by the scope of the appended claims. In particular, you can in the case of embodiments according to the invention, the features stated in the exemplary embodiments explained below can be realized in a number and combination that deviate from those of the examples. In the following explanation of some embodiments of the invention reference is made to the accompanying figures, of which

FIG. 1 illustrates a pouring head for a knife pourer with a cross-sectional view within a schematic perspective view of the pouring head,

FIG. 2 shows a commissioned work with a pouring head according to FIG. 1 in a schematic cross-sectional representation,

3 shows a longitudinal section through an embodiment of a

Casting head with varying height of the feed gap in a schematic representation shows

Figure 4 is a schematic illustration of a pouring head with in

Shows longitudinally varying gap width,

Figure 5 is a schematic illustration of a casting head with a

Feed gap shows, whose width is constant at the surface of the casting head and increases into the interior of the casting head and as well as to its outlet side,

Figure 6 is a schematic illustration of a casting head with a

Supply gap in an exploded perspective view, which is formed of two plates with an intermediate shim foil, and Figure 7 illustrates the pouring head of Figure 6 in assembled condition in a schematic perspective view.

In the figures, the same or similar reference numerals are used for functionally equivalent or similar characteristics, regardless of specific embodiments.

Figure 1 illustrates a pouring head 10 for a Meßergießer not shown in a, a cross-sectional view 1 1 containing schematic perspective view of the casting head. Inside the housing 3 of the pouring head 10, a tubular distribution chamber 1 is formed. Under tubular distribution chamber is to be understood in this document, an embodiment of the distribution chamber as an elongated cavity. A limitation to certain cross-sectional geometries of the distribution chamber does not exist here. The longitudinal direction of the distribution chamber extends substantially in the direction of the longitudinal extension 1 of the casting head 10. On one of the end sides of the casting head is the inlet opening 4, on which the opposite end face the drain opening 5. The side surface 6 of the pouring head 10 towards the distribution chamber 1 via a feed slot 2 is opened. An opening of the distribution chamber to one of the other side surfaces of the casting head does not exist in the illustrated embodiment, but in principle z. B. for the purpose of simultaneous coating of multiple film webs possible. The feed slot 2 of the pouring head 10 presented in FIG. 1 has a width b which is constant over its length and a height h at the inlet end. The height of the feed slot is generally understood to mean the distance between the distribution chamber 1 and the coating surface 6 of the pouring head 10, in each case at the transition to the feed slot 2. In this document, the width b of the feed slot 2 is the distance b between its two opposite side faces. Chen, this distance can be made variable by non-parallel alignment of the two side surfaces both in the longitudinal direction and in the direction of the distribution chamber to the surface 6 of the casting head.

During a coating process, the coating composition flows through the distribution chamber 1 from its inlet opening 4 to its outlet opening 5 in the direction indicated by arrow 7 of FIG. The pressure of the coating material in the distribution chamber 1 exceeds the ambient pressure of the casting head, so that escapes through the supply gap 2, a portion of the distribution chamber flowing through the coating composition from the distribution chamber 1 to the surface 6 of the casting 10 and out there from the

Gap 2 emergent, illustrated in the figure by arrows 21, coating mass flow generated. In order to maintain a flow through the distribution chamber, the pressure p 1 of the coating material at the inlet end 4 of the distribution chamber 1 must be greater than the pressure p 2 at the outlet end 5. From this pressure difference results in a pressure gradient of the coating material along the adjoining the distribution chamber 1 inlet opening of the supply gap 2, wherein the pressure from the inlet end to the expires drain end of the inlet opening decreases.

FIG. 2 illustrates a coating unit 30 using a casting head 10. In the illustrated applicator 30, a film web 32 to be coated is guided around a partial circumference of a rotating roller or roller 31. The direction of rotation of the roller 31 and the direction of movement of the film web 32 are in the figure illustrated by corresponding arrows. The casting head 10 is arranged at a distance from the film web 32 in the area of the roller 31 looped around by the film web 32, wherein the coating surface 6 in the illustrated embodiment of the casting head 10 is curved to the diameter of the roller 31. In other embodiments, the coating surface 6 referred to in the jargon as Gießerlippe can be designed without such a curvature, in other words even.

A portion of the coating mass 20 flowing through the distribution chamber 1 passes through the feed gap 2 into the region formed between the coating surface 6 and the surface of the film web 32 lying opposite this. Depending on the speed of the film web, the viscosity of the coating composition 20, the pressure of the coating composition 20 in the distribution chamber and the geometry of the feed gap 2, the area between the surface 6 and the film web 32 is only partially or completely filled by the coating material 20, as shown in FIG , Accordingly, the wetting meniscus 22 of the coating composition 20 may extend from the outer edge of the surface 6 towards the supplied film web, or be positioned within the area between the surface 6 and the film web 32 as shown. At the side edge of the surface 6 facing the removed film web 32, the thickness of the coating material 20 generally tapers to the resulting thickness d of the coating layer 24, so that the coating material 20 also forms a meniscus 23 at this edge. The width of the coating layer 24 substantially corresponds to the length of the feed gap 2, wherein the length of the feed gap 2, as shown in Figures 1, 4 and 5 is shorter than the length of the distribution chamber between the inlet opening 4 and drain opening 5 may be.

The working distance of the casting head 10, d. H. the distance between its coating surface 6 and the opposite side of the film web 32, in the production of drug depots for transdermal therapeutic systems usually values between 100 μπι and 1 mm, with working distances from a range of about 100 to about 300 μπι am commonly used. The coating thicknesses d achieved with an arrangement as illustrated in FIG. 2 generally have values of approximately 50 to 100% of the working distance in the case of the coating materials 20 used for the formation of active substance depots.

FIG. 3 shows a longitudinal section through an embodiment of a casting head 10 according to FIG. 1, in which the distance between the distribution chamber 1 and the surface 6 and thus the respective height h of the supply gap 2 decreases in the direction of the discharge opening 5. In the embodiment illustrated in Figure 3, the distribution chamber 1 is curved, so that the height of the feed gap 2 from the inlet side 4 to the discharge side 5 decreases non-linearly. In embodiments of as shown in Figure 3 casting heads 10 of the height profile h _x and h (x) of the feed gap 2 coating weight to the pressure curve of the loading 20 along the inlet opening of the feed gap 2 adjusted so that the following relation (1) between the Height h (x) of the feed gap at a longitudinal position x and the pressure of the coating material p _x at the inlet opening at the longitudinal position x gives: h (x) = h (p _x ); ( 1) Since a part of the coating mass 20 flowing through the distribution chamber 1 exits via the feed gap 2 to the coating surface 6 and is taken along by the film web 32 guided past it, the pressure drop along the inlet opening of the feed gap is non-linear, so that the height profile h (x) has a non-linear characteristic.

A linearization of the pressure drop along the inlet opening of the feed gap 2 and thus of its height h (x) can be achieved in embodiments by changing the cross section of the distribution chamber 1 in the flow direction of the coating mass 20, wherein the distribution chamber cross section for this purpose continuously changing between inlet 4 and drain opening 5 is to execute.

In the longitudinal direction x or 1 in area and geometry constant cross-section of the distribution chamber 1, the contour of the formed at the transition from distribution chamber 1 to the feed gap 2 edge 8 can be calculated using mathematical models for fluid mechanics of the coating material 20 in the casting head, with known methods of numerical Fluid mechanics such as the finite element method (FEM) can be used. The numerical calculations can be carried out with the help of quantitative experiments. Alternatively, the characteristic of the height profile h (x), which in the present case is a uniform width of the feed gap 2 determined by the contour of the edge 8, can be determined by means of experimental approximation.

The reduction of the feed gap height h (x) in the direction of the discharge side of the pouring head 10 results from the fact that the flow mung resistance of a formed between two parallel walls flow channel with a shortening of the flow channel is lower. Because the lower flow resistance at a point of the supply channel ensures that despite the prevailing lower pressure of the coating composition 20 when entering the supply channel 2 per unit time, the same amount of coating material 20 can flow through this point of the supply channel, as at another Place where the coating material penetrates under higher pressure in the feed gap 2, but this has a greater height for it.

Alternatively to the formation of the feed gap 2 with a decreasing to the discharge side 5 gradient shape of the height of the local flow resistance of the feed gap 2 can be varied over the gap width b.

In a feed gap 2, which is bounded by side walls whose distance from each other with respect to the (y in Figure 3) direction y of the distribution chamber 1 to the coating surface 6 is constant, the width of the feed gap 2 in this case increases in the direction of the discharge side of the casting head 10 continuously , The course of the feed gap width b (x) is then characterized by the following relation (2): b (x) = b (p _x ); (2)

A corresponding embodiment of a feed gap 2 is illustrated in FIG.

In other embodiments, the width of the supply nip 2 at the coating surface 6 is constant, but increases in the direction Distribution chamber, based on the relative position between the inlet and outlet side to different degrees. The course of the feed gap width b (x, y) is then characterized by the following relation (3): b (x, y) = b (p _x , y); with b (x, y ₀₎ = b _0; (3)

In relation (3), bo denotes a constant value and yo the position of the exit opening of the feed nip 2 on the coating surface 6. An example of a feed gap 2 formed wedge-shaped according to relation (3) is illustrated in the schematic representation of FIG.

Due to the nonlinear pressure drop along the longitudinal direction 1 of the distribution chamber, the side walls are generally curved to form a uniform coating mass flow 21 along the length of the exit opening of the supply nip 2. For ease of manufacture, the curvature of the sidewalls may be approximated by short contiguous planar sections. The shape of the sidewalls for forming a feed gap 2 having a variable gap width may also be determined experimentally with a numerical modeling as stated above.

Of course, in embodiments of a casting head 10, a varying configuration of the gap height curve h (x) may be combined with a varying configuration of the gap width curve b (x) and b (x, y), respectively, such that a variation of the height-to-width ratio the feed gap along the longitudinal direction receives. Preferably, a casting head 10 is constructed of two with respect to distribution chamber 1 and feed gap 2 mirror-symmetrically constructed housing parts 3a and 3b, so that the variation of the height-to-width ratio of the feed gap 2 by z. B. corresponding milling of Verteilkammer- and Zufuhrspaltseitenwänden can be easily realized.

FIGS. 6 and 7 illustrate a casting head 10 which can be produced particularly inexpensively. The schematic perspective view of Figure 6 shows the essential components of the casting head in an exploded view; the perspective view of Figure 7 shows the casting head in the assembled state.

The casting head has a first plate-shaped element 60, a second plate-shaped element 61 and an interlayer element 62 referred to as a shim foil. The two plate-shaped elements 60 and 61 are hereinafter referred to as plate. In the illustrated embodiment, the second plate has a recess 70, the longitudinal ends of which are each arranged at a location which allows fluid communication with apertures 71 and 72 formed in the plate 61 and over their entire cross-section. One of the two openings acts as an inlet opening, the other as a drain opening. The elongate recess 70 forms the distribution chamber. The spacing of the distribution chamber 70 to the leading edge 73 of the second plate 61 varies along the length of the distribution chamber 70. The variation may be linear, partially linear or non-linear as described above. In the first case, the edge of the distribution chamber 70 facing the plate leading edge 73 forms a straight line in the region provided for the slot discharge, in the second case a line consisting of a plurality of straight line segments which meet at an angle. composed, in the latter case a curved line. The distance of the distribution chamber 70 to the front edge 73 of the second plate has a decreasing in the direction of the drain opening shape.

As shown, the mop foil 62 is U-shaped so as to cover the area of the side of the second plate 61 facing the first plate 60, which is not used as a side wall of the feed gap 2. In particular, the shim foil therefore covers the regions of the distribution chamber 70 which extend from the inlet opening 71 or 72 or the drain opening 72 or 71 up to an edge of the feed gap. In order to allow the flow of coating material through the inlet and the outlet opening, corresponding openings 71 and 72 are provided in the shim foil. The first plate in the illustrated embodiment has no structuring of the surfaces with respect to a formation of a part of the distribution chamber. However, in other embodiments, a portion of the distribution chamber may be provided in the first plate 60. Likewise, at least one inlet opening or one outlet opening can be arranged in the second plate. Thus, in embodiments, the coating composition may be delivered via an opening in one of the two plates 60 or 61 and removed via an opening in the other plate. In other embodiments, both plates each have an inlet and a drain opening, so that the inlet and outlet of the coating mass can be carried out in each case through both plates.

As materials for the formation of the two plates are steels such. As plastic mold steels in question. To form the shim foil plastics such. B. high density polyethylene or polyester preferred. The connection of the two plates 60 and 61 with the intermediate shim foil 62 is preferably carried out by means of releasable fastening means, such. B. with the illustrated in Figure 6 screws 66, which engage through correspondingly formed in the first plate 60 and the shim 62 holes 65 through threads 67 which are formed in the second plate 61. It should be noted that in FIGS. 6 and 7 only those components of the casting head 10 are shown which are necessary for understanding the present invention. On the presentation of further, z. B. for the adjustment of the components to each other or for the operation of the casting head 10 required components was omitted in the interest of a clear presentation. Nevertheless, such advantageous or required components are assumed to be present.

FIG. 7 shows the pouring head 10 of FIG. 6 in the assembled state. Clearly visible in this illustration are the two openings 71 and 72 opening into the distribution chamber 70, via which a coating composition is passed through the distribution chamber. By this arrangement, a U-shaped course of the coating composition is effected by the casting head 10. Preferably, the openings 71 and 72 are exactly attached to the respective ends of the distribution chamber 70. In other embodiments, the openings 71 and 72 are offset from the respective ends of the distribution chamber 70 in the direction of the center thereof. The offset can be up to 5 mm, without the casting behavior affecting cavities arise.

Regardless of the design of a pouring head whose drain opening can be connected to a not shown in the figures collecting container in a manner that from the outlet opening leaking coating mass can get into this receptacle. In embodiments, the coating composition is circulated so that it is conveyed from the collecting container back to the reservoir, or the reservoir simultaneously forms the collecting container.

In the detail illustration A of FIG. 7, a cross-section through the front edge of the pouring head is shown, at which the feed channel 2 allows a discharge of coating material from the pouring head. As shown, in the illustrated embodiment, both plates at the exit of the feed channel 2 have a projection extending along the length of the feed channel, the width of which is less than the thickness of the respective plate at the leading edge. As a result, the casting lip 6 can be designed according to the application conditions of the coating composition. However, the formation of corresponding projections does not constitute a mandatory embodiment of a casting lip.

In the embodiment shown in Figures 6 and 7, the width of the feed channel 2 is not determined solely by the thickness of the shim foil, but can also be influenced to a certain extent via the tightening torques of the fastening screws or the pressure forces exerted by other suitable fastening means on the assembly , At higher compressive forces or torques, the shim foil is pressed more strongly and thus results in a relatively narrower supply channel. By exerting these different compressive forces along the shim foil, the width of the feed gap 2, along its longitudinal extent and assuming suitably arranged attachment means, can also be varied along the flow direction of the coating agent in the feed gap. The illustrated in Figures 6 and 7 construction of a casting head 10 allows a change in slot length and

Slot width of the feed gap 2 by simply replacing the shim foil. For smaller slot lengths, the cutout in the shim foil is shorter, and in the case of larger ones it is chosen to be larger, whereby the maximum length of the slot given by the construction of the distribution chamber 70 must not be exceeded. To form wider feed slots, thicker shims are used, or two or more shims are overlaid. In other words, the width of the feed gap can be determined by the dimension of the shim foil. The thickness of the shim foil or the thickness of a shim foil stack is less than 3 mm in embodiments, less than 2 mm in preferred embodiments and less than 1 mm in particularly preferred embodiments.

The casting head 10 shown in FIGS. 6 and 7 can be quickly disassembled and cleaned, so that the changeover time required for a change in the coating compound can be kept low.

To produce coated film webs for the formation of transdermal therapeutic systems, a casting head as described above is flowed through with a coating composition. The coating composition preferably completely fills the cavity in the casting head, which is in communication with the openings for the inlet and the outlet of the coating compound, but at least as far as possible, in order to prevent the formation of bubbles in the coating. For coating the casting lip of the casting head is arranged in a distance to the film web surface as described above. The coating composition usually consists of one active ingredient-containing matrix material which is diluted in a suitable solvent, for example heptane. The coating composition may be a Newtonian or non-Newtonian liquid. In embodiments of the method, the casting head 10 is flowed through by a non-Newtonian coating composition in order to achieve a uniform application of the non-Newtonian coating composition.

According to the features of a casting head 10 designed as described above, as well as a knife pourer equipped with a corresponding pouring head, it is possible to realize a coating mass flow 21 that is uniform over the length of the outlet opening of the feed gap 2. The exact course of the height-to-width ratio is dependent on this from the flow behavior of the respective coating compound 20, so that a casting head 10 in each case has a profile of the height-to-width ratio adapted to the viscosity range or the flow behavior of a coating composition 20 to be used herewith. Casting heads formed as described are preferably used in the manufacture of transdermal therapeutic systems (TTS).

Claims

claims

1. casting head with a tubular distribution chamber (1) extending from at least one inlet opening (4) to at least one outlet opening (5) and a feed gap (2) which extends at least along part of the length of the interior of the casting head (10). arranged distribution chamber (1) laterally adjoins this and extending to form an opening of the distribution chamber (1) to a surface (6) of the pouring head (10) from the distribution chamber (1) to this surface (6), wherein the cross section of Feed gap (2) along the length of the feed gap varies.

2. casting head according to claim 1, wherein the at least one inlet opening (4), the at least one drain opening (5) and the distribution chamber (1) are arranged so that substantially no dead zones can form.

3. casting head according to claim 2, wherein between the inflow-side end of the distribution chamber (1) and the inlet opening (4) and / or the outlet end of the distribution chamber (1) and the drain opening (5) each outside the drain opening (5) and The inlet opening (4) connecting part of the distribution chamber (1) located part of the distribution chamber (1) is arranged, whose extension in the the drain opening (5) and the inlet opening (4) connecting direction is a maximum of 5 mm.

4. casting head according to claim 1, 2 or 3, wherein the inlet opening (4), the outlet opening (5) and the distribution chamber (1) are arranged so that the discharge from the outlet opening (5) exiting coating material has flowed through the casting head substantially U-shaped.

5. A casting head according to any one of claims 1 to 4, wherein the casting head comprises two non-identical plates and optionally at least one intermediate shim foil.

6. casting head according to claim 5, wherein one of the two plates comprises neither a drain opening (5) nor an inlet opening (4).

A casting head according to any one of claims 1 to 6, wherein the variation of the cross section of the supply nip (2) is formed as a variation of the height-to-width ratio of the supply nip (2) along the longitudinal direction thereof.

8. A casting head according to claim 7, wherein the width of the feed nip (2) is constant and the height of the feed nip (2) varies along the longitudinal direction of the feed nip.

9. casting head according to claim 8, wherein the height of the feed gap (2) in the direction of the outlet (5) of the distribution chamber (1) towards decreasing shape has.

10. A partially covered with a shim foil plate for producing a casting head according to one of claims 5 to 9, wherein both the shim foil as well as the plate each have an inlet opening (4) and a drain opening (5), characterized in that the arrangement of Shim foil and said openings enables the production of a casting head whose supply gap (2) has a height which has a in the direction of the outlet (5) of the distribution chamber (1) towards decreasing shape.

1. A partially covered with a shim foil plate for producing a casting head according to one of claims 5 to 9, wherein the plate for forming the distribution chamber (1) has an elongated recess, characterized in that the recess and the shim foil are arranged so that after the casting head has been produced, a feed gap (2) can be formed, the height of which has a shape that decreases in the direction of the outlet (5) of the distribution chamber (1).

12. A partially covered with a shim foil plate according to claim 10 or 1 1 or casting head according to one of claims 5 to 9, wherein the shim foil has a thickness of less than 3 mm, preferably less than 2 mm and most preferably less than 1 mm having.

13. A partially covered with a shim foil plate according to any one of claims 10 to 12 or casting head according to one of claims 5 to 9, wherein the shim foil is insoluble in a suitable for the production of transdermal therapeutic systems (TTS) solvent and the solvent is preferably heptane is.

14. Casting head according to one of claims 1 to 9, comprising a partially covered with a shim foil plate according to one of claims 10 to 13.

A casting head according to claim 7, wherein the height of the feed nip (2) is constant and the width of the feed nip (2) varies along the longitudinal direction of the feed nip.

16. casting head according to claim 15, wherein the width of the feed gap (2) in the direction of the outlet (5) of the distribution chamber (1) towards progressive shape has.

17. Casting head according to claim 15 or 16, wherein the progressive form has a non-linear characteristic.

18. A casting head according to any one of claims 15 to 17, wherein the casting head comprises two non-identical plates and an intermediate shim foil, characterized in that the width of the feed gap (2) is determined by the dimensions of the shim foil.

19. Casting head according to one of claims 1 to 9 or 12 to 18, wherein the at least one inlet opening (4) and / or the at least one drain opening (5) and / or the at least one tubular distribution chamber (1) and / or the Feed gap (2) is at least partially filled with a drug-containing coating material.

20. Device comprising the pouring head according to one of claims 1 to 9 or 12 to 19, wherein the drain opening (5) is connected to a collecting container so that the out of the drain opening (5) exiting coating mass can pass into said collecting container.

21. A process for the uniform application of a non-Newtonian coating composition to a film web, characterized in that a casting head according to one of claims 1 to 9 or 12 to 19 is flowed through during the coating process with the non-Newtonian coating composition.

The method of claim 21, wherein the non-Newtonian coating composition is an active-ingredient-containing composition for the preparation of transdermal therapeutic systems (TTS).

A method according to any one of claims 21 to 22, when dependent on any of claims 10 to 13, comprising a step of applying compressive forces to the shim foil varying along the longitudinal extent of the feed channel to vary the width of the feed channel along its longitudinal extent.

24. Use of the casting head according to one of claims 1 to 8 or 1 1 to 18 in the manufacture of transdermal therapeutic systems (TTS).