HUE029180T2 - Metering coater for highly viscous coating compositions - Google Patents

Description

Meterfog eoater for highly viscous ensuing eompossitfens

The present invention relaies to so applicator unit fer continuously applying viscous coating, coïspesstiefîs t© fell sheets», ásd Is partietsisr to as applicator mi: for producing coatings having, uniform coating thicknesses.

Applicator units for eoatisaousiy costing feit Sheets vvith viscous coating compositions generally comprise a region at witch, a coaling composites is applied by a so-called coaler in defined dosage to the fed sheet. Depending on the coating task or formulation of the coating: composition, different confers, such as, for example,; extrusion coalers,, slop-pad costers, doctor blade eoaters, deposition •confers, roller or roll eoaters or slot eoaters, and,. of these, in particular metering eoaters are ttsed. As slot eoaters are generally termed eoaters in which the coating composition exits the coating head via a slot-shaped gap. The slot-shaped gap connects a distribution chamber, formed inside the feeder head and provided with an Inlet, to the outer side of the: feeder head and serves for the defined supply of a coating composition from the distribution chamber to the surface of the feeder head, in the case of metering eoaters, the distribution chamber is additionally connected to an outlet different from the slot-shaped feed gap, whereby inure coating composition flows through the distribution chamber than exits vis the feed gap.

Coatings fer producing active substance depots for transdermal therapeutic systems (TTS) require a particularly even coating application, sincs this. In addition fe a homogeneous active substance distribution is foe coating composition, is. a precondition for a targeted dosage: of transdermaUy administerei! active substances.. Metering eoaters enable a precisely dosabte, even application of coating eoroposit feus to fell sheets and are therefore frequently used to produce active: substance depots for transdemial therapeutic systems.

Metering eoaters have as the core element a feeder head comprising a tubular distribution: chamber which is arranged inside anti which along its length, via a slot-shaped gap, Is open towards one side of the feeder bead. For coating, the distribution chamber hi standard metering eoaters is flowed through lengthwise by the coating composition or the coating material, wherein foe coaling composition, for this purpose. Is fed ;<:< the distribution chamber at an end formed as the inlet, and is led off via the other end formed as an outlet. The pressure of the coaling composition in the distribution chamber is higher than foe ambient pressure o f foe feeder bead, so that a parr of the coating composi tion supplied via the inlet Is guided visa the slot-shaped gap to the outer side of the feeder bead. The coating composition which exits the feeder head via this feed gap wets the foil sheet which is guided along adjacent thereto, so that it is carried along: by this fell sheet and subsequently forms on this a layer of coating material. The length of the feed gap: here determines the width of the coating layer applied fo the foil.

The thickness of a coating: layer applied as described is substantially determined: fey the flow of foe coating material through the feed gap, the distance between the feed gap and foe foil sheet, the viscosity of the coating material and the velocity of the foil sheet relative to the feed gap or foe metering eoater.

The lew· of fee eaatteg material through Hm lsei gap Is, for its part, a fonction of foe pressure prevailing hi the âhtrihmi&amp;n chamber and -of the height -mé width of she feed gap. An analytical déterminai son of the parameters necessary fm a spéciit: coating, thteiteess fa possible In principle, yet in practice is: supplemented or replaced by an experiment# determination, fre*pea%' wish the use of empirical values·. A coating thickness which is anifenn Over she width of the foil sheet repaires a material flow of the coating composât loss that is aatfön» -over the lengte of the feed gap. This Is given when the pressure·: drop along the flow direction of the distribution chaosber Is negligible. Assuming equal flow velocity of the coating composition within the distribution chamber, foe pressure drop between the Met and outlet of foe distribution chamber is a fonction of the distance between the Inlet: and the outlet and the viscosity of the coating material. The higher the viscosity of the coating material or foe greater the distance between the inlet and outlet of the distrlbotion s&amp;amfeer, the greater is the pressure difference. It has been shown that the pressure drop in respect of foe coating widths of currently up to 158$ mat which are today used for the production of sransdemmi foerapetstie systems, in conyaucti«» with foe new active: stsbstaace-eontat-ting coating ccsnpositions which are used for this, having viscosities within foe range from around Sbô to around 5080 mPas, is m longer negligible and leads to changes in costing thickoess over the width of the fei sheet, which changes lie outside the tolerances which are to he observed, A reduction of tee costing thickness: variation caused by the pressure drop along the longitudinal dlreeffon of the distribution; chamber can be achieved by arranging that end often feed: gap which faces towards the inlet of the distribution chamber doser to the foil: sheet than that end of the feed gap which feces towards the outlet of the distribution chamber. A compensation of the coating thickness: variation by an appropriate!! inclined orientation of a metering coûter Is possible, however, only in small measure. in particular since She pressure along she distribution chamber does not fail linearly and thus also; foe How of She coaling eornposiilon introduced from the distribution chamber into the Seed gap varie s aon -lineariy slosrg fo e length of the feeder head.

For the reduction of a variadon m coating thickness caused by foe pressure drop in the distribution chamber, also a plurality of coating material streams ess he produced in the distrlbufion chamber. For Instance, Site coating composition can be fod In centrally to foe distribution chamber and. eats then he led off at its two fees ends. Tbc reverse case, with a two-sided feed-m and a central evacuation of the «eating composition, is likewise possible, Since each substremn of the coating composition in such multi-stream feeder beads covers only half the path length, foe pressure: drops in foe distribution chamber are reduced to half. Through the: use of a plurality of inlets and outlets, the pressure drops along the length of the distribution ehansber cun be further reduced. Ho wever, appropriate designs: are not only very complex in terms of production, but call for a precise matching of she individual substreasris during use. Moreover, although fluctuations to the eoafing thickness with nvuit!-stream feeder heads can be lessened, they cannot be totally avoided due to the pressure drops in foe distrlbu; ion: chamber, which, even, though reduced, are nevertheless si ill present.

It is tirerefefe desirable to define metering eöakrs. whisk with simple tmms enable m even coating ©f ibîi »tests. 1b addition, it Is desirable to define a feeder hete which cas be produced cheaply. lï Is also desirable ta define a feeder head whose .slot width can he varied k dependence m. the coating composition. Furthermore, it. is desirable: to define &amp; feeder head which cm- fee easily and cheaply cleaned ate ess fees fee used fer différés«: coating .compositions·. It Is also desirable to define a feeder head in white the 'length of the feed gap, ami thus the width of the costing layer applied to a feil, can he easily varied, Ihalmdi ments of appropriate metering eoaters: comprise a feeder head having a tubular distribution chamber, extending from at least este inlet opening to at least este outlet opening;, ate having a. feed gap which connects to the side1 of the: distribution chamber, at least along part of the length: of the said distribution chamber arranged within the feeder tread.. The feed gap here extends from the distrifeuiiou chamber to a surface of the feeder head in order to form an «peakg in the distribution chamber to the said surface, whereto the cross section of the feed gap varies along the length of the feed gap.

Doeatoeni CM 597 928 A5 discloses a feeder head according to the preamble of Claim I.

In embodiments of feeder heads according 1® $fe inveatton, the at least on® inlet opening, the at least one outlet opening, and the distribution chamber are arranged sscfe that basically no nestral «ones css he formed. By the term "neutral mms” are here understood regions in She distribution ehamher which, during operation of the feeder tread, are not flowed through fey the coating composition, or not such that they cats: fee regarded as part of the principal flow, directed from the inlet: opening; to the outlet opening and the feed gap, of the coating: composition, By the term "basically no neutral tones" should he understood that the volume of neutral armes which may be present, fer instance in the region around an inlet and otstlet opening, is so small that they do tset lead to the fertrratlon of deposits of the coating comppsiliots: and do not adversely affect the: principal flow of the coating composition. In some confsgnmtions, a. portion of the distrihtsîion chamber which is located outside the portion of the distrlhafioo chamber connecting the outlet opening and the inlet opening Is arranged between the inlet-side cod of the disírlbuíion chamber and the inlet opening and/or between the outlet-side end of the distribution chamber and the outlet opening respectively., fee extent of which portion is a ntaxhnmn of 5 mm in the direction connecting the pofiét opening and the inlet opening.

The feeder heads: are designed sects dial the inlet: opening, the outlet opening ate tire distribution chamber are arranged in such a way that a coaling material which «sits the outlet opening has passed through the feeder head in a substantially U-shaped manner. By 'Tl-shapte" should here he understood mi, at leas! in first approximation, plane geometry,: in which a straight or curved leg region respectively connecta to each of the two ends of a straight or curved middle region, wherein both leg regions extend away from the middle element towards she same side.

Versions of the feeder bead; can comprise two non-identical plates and optionally at least one shim foil in: between said plates. By "plate" should itéré fee understood a planar, is first ppproxisaatton Oat component, the thickness dimensions of which arc substantially smaller than its; dimensions transversely to the thickness direction, The thickness of the plate can however te different at different places os the plaie., for instance due to recesses formed in the piste or due to projections. By shun foil should be understood a thin, planar nem which is used as an interlay. is some embodiments of the feeder head, ose of the two pistes eomprlsss neither an outlet opening »or m inlet opening, so that both openings ate fented: no: the other of the two plates and tints a psrffeaferiy simple and easy-to-clean structure of the feeder head is obtained. .in some- «ÉthodimeMs· -of appropriate feeder heads, the variation of the cross section of the fed gap is pfeerahly- designed as a variation of the Imightdo-width ratio of the fesd gap along. Its .loogttndlnsl direction, whereby a. flow resistance which varies with respect to the fongltudirml direction of the feed gap: Is obtained.

Con figurât ions of sueh embodiments advantageously have a constant width of the feed gap and a height of the fed gap which varies along the longitudinal direction of fe feed gap, whereby the feed gap can be produced in a particularly simple manner, í%«fere<í configurations: hereof have a profile of the height of the feed gap which decreases m the direction of the dot let of the distribaifen chamber,, whereby the pressure drop in the dfstnbaltofi chamber can be easily compensated.

Solutions to the above objectives comprise a plate, partially covered with a shim fell, for producing a feeder head as referred to above, wherein both the shim foil and the plate respectively have an inlet opening and an outlet opening, and wherein tfce arrangement of the shim foil and of the said openings enables the production of a feeder bead, the feed gap of which: has a height having a profile which decreases: in the direction of the outlet of the distribution chamber.

Solations to the above objectives farther comprise 3 plate, partially covered with a shun fed, fer producing a feeder head as previously referred us, wherein -he piste has as elongate depression for the purpose of forming the distribution chamber. and wherein the depression and the shim feli are arranged snch that, following production of the feeder head, a fed gap. fee height of which: has a prolié which decreases in the direction ot the outlet of the distribution: chamber, can he formed. By an "elongate depression” should here he understood a recess which: forms none of the two main side feces of the plate and the longitudinal extent of which is substantially greater than Its latitudinal extent.

Solutions to the above objectives comprise, ferthertnore, a plate as previously referred to and partially covered with· a shim foil, or a feeder head, as previously defused and comprising two aon-identical plates and optionally at least one tnfervouing shim: fell in which the shim: foil has a thickness of less: ihm 3 mm, preferably of less than 2 nun, and most preferably of less than 1 mm.

Solutions to the above objectives: additionally comprise a plate as previously referred to and partially covered with a shim foil, or a feeder head, a,S: previously defined and comprising two non-identical plates and optionally at least one intervening shim foil. In which the shins foil Is insoluble in a solvent suitable for the production: of transdermal therapeutic systems (ITS) and the solvent Is preferably heptane. By ”a solvent suitable for the production of transdermal therapeutic systems: (TTS}!f should he understood all solvents which are suitable for dissolving the matrix material respectively used to fonn a TTS, and of which tire: residual quantities remaining in the matrix material during the production of a 'ITS do not give rise to any significant shut Irritations: amongst users.

Soiuticms to the above objectives aise compris« a feeder lead which has a plate partially coveted with a •shim, foil: sod haviag openings: formed thereto for the milow and outflow of coating composition Other eoofigaratioss of entbodimems of feeder heads, as: previously referred to, advantageously have a constant height of the feed gap -combined wish, a width of the feed gap which varies along the îôBgitudiæaï direction of the feed gap, wherein the: width of the feed gap can here change also along the direction pointing fears the distribution chamber to the surface of the feeder head. Such feed gap geometries can be easily proposed: by means of traditional material removal methods, such as, for example,, nulling, Freferahh, the width of the feed gap here has a profile which increases: la the direction of the outlet: of the distribution chamber. In specific configurations hereof the width of the feed gap on the .surlace of the feeder head 'is constant and widens, possibly apart írom fee inlet-sidg: sod of the : feed: gap, both in the direction of the distribution ehamher and in the direction of the mdlei-side end of the feed gap. Such a geometry enables a variation of the flow resistance along the feed gap wlthont changing the wetting conditions along the outlet opening of the feed gap.

For the compensation of a non-linear pressure drop in the distribution chamber, preferred etnbodfetenfs have a non-linear characteristic of the profile of the helght-to-wldth ratio of the feed gap. Preferably, such a non-linear characteristic is established using a calculation according to a mathematical model of the fluid mechanics of a coating material in the feeder head, wherein: experimental delertnmatio&amp;s can he called upon. Alternatively, the non-linear characteristic is determined purely experimentally.

In seme embodiments, life feeder head comprises two son-identical plates and an Intervening shim toil, wherein the width of fee: feed gap is determined by the dimensions of the shit» feil.. By "dimension” of the shim foil should here be understood the thickness extent thereof which can assume different values at different places, for instance in order to realize a feed gap width which varies in the longitudinal direction and- or heigh· difcctsoo of the feed gap.

In further embodiments of the feeder head, the at least one islet opening and/or the at: least one outlet ©petting andfer the at kast one tubular distribution chamber and/or the feed gap k at leas; partially füled with an active substance-containing coating material.

Solutions to the above: objectives additionally comprise a device comprising a feeder head as referred to above, wherein the outlet opening is connected: to s collecting vessel such that the: coating composition which exits the outlet opening can make its way snts the said collecting vessel.

Solutions to the above objectives further comprise a method for ewaíy applying a non-Newtonian coaling; composhion to a foil sheet, wherein a feeder head as referred to above is flowed through with the non-Kfewtonian coating composition during the eoaflag process. By &amp; "non-bfewtonlap coating composition” should fee understood a liquid fluid which has a. behaviour that differs from a bfewtonian Bald, be. a fluid with linear, inelastic flow behaviour, m which the shear rate is proportional to the shear stress, »ft some embodiments of the method. the «'PO-NewtOííían coating composition is art active substance-containing material for producing trunsdenua] therapeutic systems (111.), if a feeder head having a sh'im foil is esed, She method for varying the width of the feed channel along its longitudinal extent can comprise a step for applying to the shim foil pressor« forces which vary along the longitudinal exteat of the feed channel.

Solutions to Site above objectives also comprise: use of s feeder head, ss previously defined, la the production of transdermal therapeutic systems (TTSJ.

Furs tser features of the invention: emerge front the following description of illustrative embodiments in-conjunction with the cfaiisS: and the accompanying figures, ft should be pointed oat that the invention is not limited to the embodiments of the described illustrative embodiments, but is defined by the scope of the accompany tog patent claims. Is particular, is. embodiments according to the Invention, the features which are cited in- the illustrative cntbodlments set out below ca® be rsalked in a number and combination which differ Irens the ««amples* In she following ekseidaiion of some illustrative embodiments of the hsven tien,. reference is suade to the .accompanying figures, of which Figure 1 illustrates a feeder head for a meieriog coaler wish a eross-aectiomil representation within a schematised perspective view of the feeder head.

Figure 2 shows an applicator unit having a feed et head according to Figure I in a schemstkeb cross-sectiona! representation, figure 3 shows a longitudinal section through as embodiment of g. feeder head with varying height of the feed gap in a schcnratked represerbaiiou,

Figure 4 shows a schematic illustration of a feeder head having: a gap width which varies In the longitudinal direction.

Figure 5 shows a schematic illustration of a feeder head with a feed gap whose width on the surface of the feeder head is constant god ioereases into the inside of the feeder head and towards the outlet side thereof..

Figure d shows in a perspective exploded representation a schematic Illustration: of the feeder head of the present Invention with a. feed gap, which feeder head Is formed of two plates with an intervening shim foil, and

Figure 7 illustrates the feeder head of Figure b in the assembled: slate In a schematic, perspective representation.

In the figures, same or similar reference symbols are used, -for functionally epolvalent or similar characteristics, irrespective of specific enlbodrsnests.

Figure 1 illustrates: a feeder head IS for a metering coûter fnot repres.enfed in deiaih in a schematised perspective view, containing: a eross-sectional representation: Π, of the feeder head. Inside the housing 3 of the feeder head lb is formed a tubular distribution chamber 1. By tubular distribution chamber should is Ibis document fee understood a mnfi&amp;wMÎm of the distribution chamber as an elongate cavity. A limitatios to specific cross-sectional geometries of the distribution· chamber does not here exist. The longitudinal direction of ehe dis-riburion chamber extends substantially m tlfe direction of the longitudinal extent 1 of the feeder head HI, On one of the end feces of the feeder head is feand the inlet opening 4,; m. the end face opposite thereto the outlet opening 5. Towards the side feee 6 of the feeder head lb, the dislrifeuiioo: chamber i is ope® vis a feed, slot 2. in the represented embodiment, an opening iß the distribution chamber te one of fee ether side faces of the f«*dor ihesd (loss :mi exist, yet m principle is possible, for example ter #as purpose of coating of a plurality of foil sheets simultaneously. The food slot 2 of rise feeder head ; 0 depicted In Figure 1 has a width h which is constant over its length and at the inlet end a. height k. As the height of the: food slot is understood, in general torsos, the distance between the dlstrihutkm chamber I and the coating surface é of the feeder head ML respectively at the transition to the feed slot 2, As the width of the feed slot '2 &amp; termed in tlris document ihe distance b between its two opposing side faces, wherein this distance cm. he designed't# he variable by son-garaflel orientation of the two side faces both in the ionghodirtai direction and in the: direction from the distribution chamber to tire surface 6 of the feeder head,

Duflsg a cosing: process, the coating: composition Hows through tire distribnion chamber 1 from Its Inlet opening 4 to its outiét opening 5 in the direction indicated by the arrow 7 of Figure I, The pressure of the eostitsg composition m the distribution chamber 1 here exceeds the ambient pressure of the feeder head, so that, through the feed: gap 2, a part of the coating composition flowing through the distribution; chamber escapes irons the distribution chamber 1 towards the surface 6 of lise feeder head 10 and generates there a coating composition stream which exits the gap 2 and is illustrated la the figure by arrows: 2 L For the mamtersanee of a flow through the distribution chamber, the pressure pi of the coating matériái at the folet-side end 4 of the distribution chamber ! Is greater than the pressure p2 at its outlet-side end 5, Given equal flow velocity, this produces a pressure differential which Increases with the viscosity of the coating: composition, between the Mow and outflow of the distribution chamber 1. This pressttre differential gives rise to a pressure gradient of the coating composition along: the intake opening of the feed gap t, Which intake opening adjoins the distribution chamber I, wherein the pressure decreases front the inlet-aide end to the outset-side end of the intake opening.

In Figure .2. Is illustrated an applicator mái. 30 using a feeder head 10. la the represented applicator unit 3Ô, a foil sheet 32 So be coated is guided m-mmá ti partial circumference of st rotating roller or roil 31. The rotational direction: of the roller 31 and the snailosml direeiioa of the foil sheet 32 are illustrated' in the figure by corresponding arrows, is that region of the roll 31 which is enveloped by the foil sheet 32, the feeder bead 1Ö is arranged at &amp; distance to the fell sheet 32, wherein the coating surface b, in the represeused embodiment of the feeder bend MS, is realised in a curve tailored to the diameter of tbs mi 3L In other embodiments:, the eoatlag: surface h, also referred its in technical jargon as the coaler tip, can: he realized without such a earvature, in ether words flat. A part of the coating composition 20 flowing through the distribution chamber i makes its way through the feed gap 2 into the region which is fenned between tint coating surface is and the thereto opposing, surface of fee foil sheet 32. Depending m the velocity of the foil sheet, fee viscosity of the coating eomposithm 213,. the pressure of She coating composition 20 in the distributios chamber sod the geometry of the feed gap 2, the region between the surface 6 and the foil sheet 32 is here filled only partially, or, as represented io Figure 2, completely, hy the coating material: 2d, Correspondingly, the wetting meniscus 22 of the coating composition 2§ can extend fern the outer edge of the: surface 6- in fee direction of the supplier! foil sheet, or can be arranged, as shown, within the regions between the surface 6 and the foil sheet 32:, Ön ihm side edge of the surface 6 which faces towards fee ied-off foil sàeet .1¾ foc thickness of tàe casting material 20 generally tapers to· the reseÄg: tMekrasss d of the eöatibg laver 24, so ihat Ore coatirg material 20 oa this edge likewise forais a mCotseus 23. The width o f dm coating layer 24 substantially corresponds: 1© the length of the teed gap 3,. whereto the length of the teed gap 2. as is represented ia Figaros f, 4 arad. 5, eara fee shorter than the length of the d istribution chamber between the islet óperaisg 4 and: the outlet opening 5.

The working; distance of the feeder head It), ho, fee distance, between its coating surface é .and the thereto opposing side of die foil sheet 32, gene rally Iras in the production of active substance· depots: for transdcmml therapeutic systems values between 18b pm: and ! mot:, wherein working dtsiaaccs ifom &amp; range from around 188 to ars'uad 3D# pm are most ireguetifly used. In ihe case of the coating materials 2b used to fontt active substance depots, foe coating thicknesses: d obtained with ns arrangement as illustrated m Figure 2 generally bay« values of around S8 to 188 % of the working distance.

Figure 3 shows a loagitudmai section through au embodiment of a feeder head ID according to Figure 1, in which the distance of foe distrlfeutioa chamber I to foe surface h, and thus the respective height h of the feed gap 2, diminishes 1st the direction of the omter opening 5. In the embodiment illustrated in Figure Î, the distribution chamber 1 is of curved eoastractloo., so foal foe height of the feed gap 2 decreases non-linearly from the mist side 4 to the outlet side 5. In configurations of feeder heads Id as shmvn in Figure 3, the height patter» hs or bfx) of the feed gap 2 is tailored to: the pressure pattern of the coating composition 28 aiong the intake opeoiug of the feed gap 2, so that the following relationship (f} between foe height hfu) of the feed gap at a longitudinal position a and the pressure of the coating 'material p* at tbs intake opeoing at the longitudinal position x is obtained::

(!)

Since a part of the coaling composition 28 flowing: through the distribution: chamber I exits via the feed gap 2 to the coating surface 6 and is there carried along by the fed sheet 32 which is led past, the pressure drop along the intake opening of the feed gap has a non-iiaear patters, so that the height pattern h(x) has a n&amp;a-tnesr charaeterlstfe. A tlneamatfeu of the pressure drop along foe intake: opening: of foe feed: gap 2,: and thus of its height patters h(x):, can be achieved In some embodiments by changing the cross, section: of the dlstrlhutioa chamber 1 in the flow direction of the costing composition 28, wherein the distribution chamber cross seel km must be realised such that, to this effect, it constantly varies between the intet opening 4 and the outlet opening 5.

If the cross section of the distributiou chantfeer 1 remains: constant in the longitudinal direction x or I is ares sud geometry·, the contour of the edge h formed at the transition from I he d istrifem ion chamber 1 to foe feed gap: 2 can be ealcalsfed with the aid of matheomtlcal models for the fluid mechanics of tbs coating composition 28 lu the feeder head, whetdn known methods of numerical fluid mechanics, such as, fur instance, the Fisitefolements-fofethod fFEM). can fee used for this.. The numerical calculations can here he conducted with the aid of guautltative experiments. Alternatively, foe characteristics of foe height .palters fox), which is the present case of a uniform width of the feed: gap 2 are deiennined by the: contour of Ihe edge 8, ess be determined: by means of experimental apprsxtmsitos.

The redaction of the feed gap height h(x} fo the hlreeifotv of the outlet side of the feeder head 10 derives from the fact that the fimt resistance of a .fossr passage formed between two parallel walls becomes lower with a shortening of the iow passage, f or the lower How resistance at one place la the feed ôkmmiï «»sures that* despite the lower presset« of the eoattog composition 20 which prevails there, upon entry into the teed dtsnuel 2, the same -quantity of coat ing material 20 per unit of time can-flow through lids place In: the food channel ás at another place at which the coating composition penetrates into the feed gap 2 «oder a higher pressure:, hot the latter, is return,, has a greater height,. Alternatively to the configuration of the food gap 2 with a height profile which decreases towards the outlet side 5, the local flow resistance of the food gap: 2 can also ho varied via Its gap width b.

In the ease of a teed gap 2 which Is honodét! by side walla, the distance apart of which is constant with respect to the direction y (denoted in Figure 3> 'fees* the distribution chamber I to the coating, surface 6, the width of the feed gap '2: here continuously increases in the direction of the outlet side of the feeder head 10, The pattern- of the feed gap width b(x) is then characterized fey she following relationship: Ç2}::

in\ u\ A corresponding embodiment: of a feed gap 2 is illustrated In Figure 4. ïn other embodiments, the width of the food gap 2 on the coating: surface 6 is constant, feni increases differently strongly in the direction of the distribution: chamber, related to the relative position between inlet and: outlet side, The pattern of the Seed gap width h(x, ys is then (31 characterized by the following relationship:

(3) in relationship (33, ho denotes a constant value and yo the position of the discharge opening of the feed gap 2 on the coating surface &amp;. An example of a feed gap 2: of wedge-shaped' configured»» in accordance with relationship (3)'is illustrated in the schematic representation of figured.. ISne to the non-itaear pressure drop along the longitudinal direction I offne distribution chamber, the side wails, for the formation of a coating composition stream 21 Which is uni Torn· along due iertgth of the discharge opening of the feed gap 2, are generally of curved configutajion. For sin-pie!· production, the curvature of the side walls eu» fee approximated fey short annually adjoining flat portions. The shape of the side wails for the fonnatioa of a feed gap 2. of variable gap width can likewise he determined wnh a nrímmea! modelling as specified: above:, or experimentally.

Of course, ip some embodiments of a feeder head ÍÖ, a varying design of the gap height pattern h(x) can he. combined with a varying design of the gap width pattern bfx) orhí -<,y j, so that S: variation of the he ight-to-width ratio of the feed gap along its longitudinal direction is. obtained.

Preferably, a feeder head 1(1 is made up of two housing; parts 3a and 3b, which are: constructed is Mirror symmetry with respect to the distribution chausfeer f and the feed gap 2, so that the variation of the itc-;ght-to-wldth ratio of the feed gap 2 can fee easily realized fey, for example, apprcprlaiemfilfog of side walls hclosgisg to the distribution chamber mé to the feed gap. îïs Figures ë árul 7, a particrtlariy cheaply pr«d'öeMe feeder teád 18 is illustrated:. The schematic perspective representation of figure é shows thé basic components af the feeder head in an exploded representation; the perspective representation af figure ? shews the feeder head in the assembled state,. The feeder head has a first plate"!ike demerit 66, a seeood plate-like dement 61: and a« interlay ©lesnem: 62 referred: fo m tech«teal terms as a shim feit. The two plate-tike elements 60 attd 61 are hereinafter respectively referred to as a plate, in the represented embodiment, the second plate has a reeess 78., the longitudinal ends of which are respectively disposed at a place which enables a fluidic connection to openings 71 or 72, which ate formed ín: the plate 61 and penetrate this same, over the whole ef their cross section. One of the two openings pets as an inlet opening, the other as art outlet opening. The elongate recess 7b forms the distribution chamber, The distance of the distribation eh anther 70 to the front «dg« 73 of the second plate dl varies along the length of the dislribnfion chamber 76, As described above, the variation: can be linear, linear in. some sections, or nomfinear, In the first case, that edge of the distribution chamber 70 which faces towards the plate treat edge 73 forms in the region provided for the slotted spout a straight line, in the second ease a line composed of <t phsraihy of straight line segments which meet ar an angle, in the last ease a curved 1««:.. The distance of the distribution chamber 78 to tlw front edge 73 of the second plate has a profile which decreases in the direction of the outlet opening.

As shown,, the shim foil 62 is formed m &amp; 11-sbape such that it covers the region of that side of the second plate 61 which is directed to the first plate 60.,. which region Is not utilized as the side wall of foe feed gap 2, In partion for, the shim fail therefore covets those regions of the distritelKm chamber 78 which extend from the inlet opening ? ! or 72 or the outlet opening 72 or 71 up to a border of the feed gap. In order to enable the flow of coating composition through the inlet and the outlet opening,; appropriate openings 7.1 and 72 are provided in the shim foil, In the represented embodiment,, foe ftet pl ate has no structuring of the snrfoees with regard to a formation of a part of the distribution chamber, in. other embodiments, however, also a part of the distribution chamber can be provided in the first plate 68, Similarly, in the second plate at least an: Inlet opening, or an outlet opening can be arranged. Thus, In sots« embodiments, the coating composition can be supplied via an opening id one of tire two plates 60 or hi and led off via an opening in the: other piste. In other embodiments, both plates respectively have an inlet and an outlet opening, so that the inflow tmd outflow of the cosfihg composition can respectively take place throngh both plates.

As materials for the formation of the two plates, steels, such as, for example, plastic mould steels, can he considered. For the formation of the: shim foil, plastics, such as, for example, high density polyethylene ©r polyester, are preferred.

The connection of the two plates: 68 and 61 to the Intervenfog slum foil 62 is preferably made with the aid of releasable fastening mesas, such ss, for example with the screws 66 illustrated m Figure 6, which, through holes 6S appropriately formed Is foe first plate: 60: and the shim foil 62, ettgdge m threads 67 formed in the second plate 61, It «honid be pointed out that in Figures 6 and 7 only those components of the feeder head 18 which are necessary to an understandiug of the present in vention are represented.. The· reprs setters nsr of forfoer components which are necessary, for example, for the èdfusüsïéâî' of the compoitmfo -me so a aol her or for the operatic!', of tits feeder head 10 has bees widvedm she interest of a «-fear representation. However, sncb -advantageous or necessary components are assumed is be present

Figure 7 sMm- the feeder head 10 of Figure Ú m the assembled: state, la this represenî-atfoa cas clearly be sees* the two openings 71 and 72 which ©pen est Into the distrlbatfon chamber 78 and via which ». coating composition is ksi through the distribution chamber. As a molt of this arrangement, a ti-shaged coarse of the coating composition throagh the leader head Hi is produced. Preferably, the openings 71 and 72 are ámde exactly ai the respective ends of the distribution càaaîber 70. ín other embodiments, the openings 71 and 72 are arranged offset to the respective ends of the distribution, chamber 78 in the: direction of its middle. The offom can .measure op to 5 non, without cavities being formed which would adversely affect the coating behaviour.

Regardless of the design of a feeder head, its outlet opening can he connected to a collecting vessel (not represented in. the figures) in such a way that the coating composition cxitisg the outlet opening can masse its way into this collecting vessel. In some embodiment», the coating; composition is circulated, so that it Is conveyed from the collecting vessel back to the storage tanig or the storage tank simultaneously forms the collecting vessel. la the detailed representation A of Figaro 7, a cross section throngh the front edge o f the feeder head: is shown, at which iront edge the foed: channel 2 enables a discharge of coating composition from the foeder head. As shewn, in the represented embodiment both plates have at the exit of the feed channel 2 a projection which extends along the: length of the feed channel and the width of which is less than: the thickness of the respective plate at the iront, edge. As a result, the coaler Up 6 can he designed in accordance with the application conditions of the costing composition. The formation of appropriate projections does not however constitute anessem isi configuration of a coaler lip.

In the embodiment represented in Figures: ë so# 7, the width of the feed: channel 2 is not solely determined by die thickness: of the shhn foil, hot can also be influenced within certain limits by the tightening: torques of the fastening screws nr the pressure forces applied to the arrangement; by other suitable fastening means. Given higher pressure forces or tightening torques, the shim foil Is more strongly pressed and thus results its a relatively narrower feed channel. Througls the application of different pressure forces to the shim foil along this: same, the width of the feed gap 2 can be-designed so as so vary along its longitudinal extent and, presuming suitably arranged fastening: means, also along the flow direction of the coating means in the food gap.

That design of a foeder bead 10 which is Illustrated is Figures 6 and 7 enables a change of slot length and slot width of the teed gap 2 by plain and simple exchanging of the sh im roil. In the ease of smaller slot lengths, the cafoat m the shim foil Is chosen shorter, in the ease of larger slot lengths correspondingly larger, wherein the maximum length of the slot that is given by the: design of the distribution chamber 70 most not be exceeded. For the formation: of wider feed slots,; thicker shim foils arc used, or two or ©tore shim folia are laid cute on Sop of another. In other words, the width of the feed gap can be determined by the: dhnension of the shim fori. The thickness: of the shim foil or the thickness

Claims (8)

1. of fi shim foil staekts is some embodiments fess ihat* 3 mm, 1» preferred embodiments less than 2 mm, smd iá pmtfetiiarly preferred embodiments fess than I mm.. That feeder head tő represented is Figwes ê mâ 1 cas be galcldy oisrsantled má cleaned, so isst the changeover iiaie which is necessary upon a change of coating composition mn be s»p|i For the production of coated foil sheets for the formation of transdermai therapeutic systems, a feeder head as previously described is flowed throngb: with a: coating: composition. Preferably, the coating composition fibs the cavity Is the feeder head, which: cavity is connected to the openings for the fellow sad outflow of fee coaling: composition, completely, or at feast as- tar as possible, m order fe* prevent: blistering: m the coating. For fee coding, the eoafet lip of the feeder head Is arranged at a distance, as previously described, to the: foil sheet surface. The coating; composition generally consists of an active snbsiance-comolnmg matrix infiferlal, which Is diluted in a suitable solvent, for instance heptane. The coating composition can eoitsfifere a hlewfenian or non-hiewtoniar, ligáid, fu some embodiments of the method, the feeder bead 10 is flowed thcungh: by a non-Kewtonisn coating composition in order la achieve an even applicstioo of the norwfeewtonian coating composition. A feeder head ÍÖ formed, m accordance with the features of an embodiment as describes! abstve, and a metering coater equipped "with a corresponding feeder head, enable the realization of a coating composition stream 21 which is mdform over the length of the discharge opening of the feed: gap 2.. The precise pattern: of the height-to-widtn ratio: is here dependent on the flow behaviour of the respective coating coarpositioa 2Ô, so that a feeder head Id respectively has a .patter®· of the helghl-to-width rut to which Is tailored to the viscosity range or the flow behaviour of a eoating composition 20 to be ttsed herewith. Feeder heads which are formed as described are preferably used in the prodsenou of transdermal therapeutic systems (TTS), Mérd tin fii fej mg y vîsxfeuæitàsé rétegképző anyaghoz. FZÂBADAi. M ! IG II N Y FOK TO K 1. ôatê&amp;j egy, legalább egy bevezető nyílástól (4) legalább egy kivezető nyitásig (S) terjedő, cső alak« elosztó kannával ÍJ) és egy ad&amp;golófessel < 2 i, ami az onfefej ( 10} belsejében elrendezett elosztó kamrával fi) is osszanak legalább egy része merne« az elosztó kamra <t> oldalához csatlakozik, ès m elosztó kamra (I) egy nyílásának kialakítására m. óntdfej ( 1 Oi felületén (6) az elosztó katonától {1} a felhletsg (ói terjed, ahol az adagolórés {2i keresztmcisze-e adagolórés 12) hossza mentén változik, azzal Jéifemezvcy hogy a bevezető nyílás <4>, a kivezető nyilas (5) és az elosztó lkamra (1) égy van elrendezve, hogy egy, a kivezető nyilasból í 5} kilépő rétegképző anyag sz ömőfejen lényedben U alakban folyik át.
2. 2. Az ifi igénypont szerinti öntőiéi, ahol a legalább egy bevezető nyila» (4), a legalább egy kivezető nyílás (S) és az elosztó kamra ( i} úgy van elrendezve, hogy holt tér ne alakulhasson ki 3. A 2, ígCírypont szerinti öntőiéi, ahol az elosztó kamra (!) bevezető vége és: a bevezető nyílás (4) és/usgy az elosztó kamra (1) kivezető vége és a kivezető nyílás (5) közöli tstndenkor egy, az elosztó kamrásak (I) a bevezető nyílás; (4) és a kivezető nyílást (5) összekötő részén kívül elhelyezkedő része va«, aminek a kiterjedése a bevezető nyílást (4} és m kivezető nyiiást (S) összekötő irányban legfeljebb 5 mm.
3. 4. Az i - 3, igénypontok Mmsslylke .szerssii őnfofoj, ahol az öntőiéi k#neöt egyforma lapot és legalább egy,, közöttük elhelyezkedő, U alakú vóőőtólía va« az adagoló rés lehatárolására, ahol az adagoló rés: vastagságás az adóst esetben nyomóerővel megváltoztatott vastagságú vádófólk határozza meg 3 mattié! kisebb, előnyöse;? 2 tnm-nél kisebb, még előnyösebben 1 ims-néi kisebb ékekbe;?, és ahol a védöfóila a rétegképző anyagban lévé oldószerben nem oldódik, 5, A 2, igénypont szerinti östöiéj, ahol a két lap mm tártalrnaz sem bevezető nyílást (4) és a kivezető nyílást (5), é, Az I ~. 5, igénypontok bármelyike szerinti öntőié}, ahol az adagold rés (2) kemszl83«íszeísaek változása az adagoló rés (2) magasság-szélesség Mwémk a hosszirány mentés történő változása szerint van kialakítva.
4. 7. A é, igénypont szerinti öntőié}, abol az adagold: rés (2) szélessége állásidő, «sagsssäga pedig az adagoló rés hossza mastes változik. 8.. A 7. igénypont szerinti öntőiéi, ahol az adagoló rés (2} magasság;;, az elosztó kamra < 1} kivezető nyílása 0} iéié esökkenŐ léfotásó.
5. 9. A d. Igénypont szerinti öMöfef, aböl az adagoló rés (2} magassága állandó, és az adagoló rés (2) szélessége az: adagoíörés hossza mentén változik. Ä. A il igénypont szeritói östő-fej, altól a« adagoló rés: (2) szélessége az elosztó kamra ( 1 ) kivezető nyílása (ál léié növekvő lefusásü. 11. A 6 ···· JŐ. Igénypontok bármelyike szermti öntőié}, shal az adagoló: rés: keresztmetszetének váltózása nem lineáris jellegi.
6. 12. Az 1 - ki. Igénypontok bármelyike szerinii ómóisj. ahol a kivezető nyitás (5} ágy vari összekötve egy felfogó tartállyal, bogy a kivezető nyílásból (5,s kilépő rétegképző anyag ebbe a felfogó tartálybajnihai.
7. 13. Eljárás egy nem newtoni folyadékból állá rétegképző »Kyag felhordására egy fólia szalagra, azzal jellemezve, hogy a nem newtoni folyadékból álló rétegképző anyagot egy, az I - 1 E igénypontok bármelyike szerinti öntofejers vezetjük át. 14.. Á 13. igénypont szsrlm; eijárás, áltól a -mm mmtmí folyadékból állá rétegképző anyag egy hatóanyagot tartalmazó n?assza tratsszderntális gyógyászati rendszer (T'FS) előállítására.
8. 15. Az I 11, igénypontok bármelyike szermii öntőié} alkalmazása trasszáemrális gyógyászait msdszer (TTS) előállítására.