DE19847274A1 - Tablet manufacturing pressing tool comprises a stamping element with an elliptical boss surrounded by a base - Google Patents

Abstract

Tablet manufacturing stamp e.g. for medical treatment comprises a stamping element (2) with an elliptical boss (4) surrounded by a base (3).

Description

The invention relates to a tablet punch, the embossing element of which is one of a flat Has the base surrounded by pins. In particular, the invention relates to press works witnesses that are used to produce well tablets or well tabs. The The upper side of a large-volume tablet has a hollow embossed into it, which connects to one another the assembly aisle is filled with another material, especially those who are poured out can.

Hollow tabs are made in particular from substances that, in combination with whose substances become effective. Often there is the situation that the under Different substances then develop their effect most advantageously when they are used precisely defined sequence go into solution during the application to get together in dissolved form to be able to work. A common area of application for this type of active agent addition is machine dishwashing. To the user the portioning of the rinse aid or, more generally, the detergents, dishwashing detergents, cleaning agents and washing aids to facilitate whoever which compresses the added quantities, which are matched to the machine capacity, into tablets.

Powdered or granular active agents, which are more effective because of the above unfolding should be added separately, are thereby in discrete layers over pressed each other. If one or more of the combination active agents was originally used in pasty or liquid, for example molten form, which are suitable for Verpres solution is unsuitable, the formation of a depression in the tablet surface is a problem time-honored form for the design of all desired substances of an active agent Combination absorbing tablet. In this cavity, the liquid, melted zenen and / or pasty agents are entered and ver after filling consolidate.

This leads to very special problems for the pressing tool, since the tablet surface is not even, but profiled. This results in the different surfaces geometries of the corresponding embossing element, different pressure and abrasion methods conditions. Because the tendency for substances to be pressed to adhere to the embossing element ment, among other things, from the specific surface pressure and the surface geometry certain pressure vectors are dependent, certain parts of an embossing element profile tend especially to buildup or caking. Such attachments result in the sequence many pressings to increasing roughness of the tablet surfaces on the ent speaking bodies that lead to deviations in the proportions of the substances and to which can lead to the tablet breaking. Breaking a tablet in the tablet press, leads this leads to considerable impairment of the manufacturing process.

The older German patent application DE 198 38 103.4 (Henkel KGaA) suggests the solution of these problems to design profiled embossing elements of tabletting punches so that their surfaces have adhesion-preventing or at least adhesion-reducing properties have and their surface is designed in such a way that the tablet produced therewith is a has sufficient mechanical stability. The tableting punches are designed in this way leads to the fact that their flat bases can be walked in the press cycle and the pin is incompressible and is coated at least to reduce adhesion.

When using the tableting punches disclosed in this document, however, a white occurs Another problem: If the depression generated by the ram is removed in the molded body poured, the cavity filling does not adhere optimally to the pressed molded body, but leaves push yourself out of the recess by applying slight pressure. With mechanical stress the molded body (e.g. case or packaging operations) can consist of the cast "core" the trough fall out or be shaken out, so that the consumer at least a part cannot be provided with a uniform molded body. The Vermei It was the object of the present invention to address these problems. In particular, should be a Press tool are provided, the use of which improves the mechani rule stability of the moldings produced with its help even after the filling process enables.

The above problems are solved according to the invention in that the one aforementioned tabletting stamp is designed so that its flat bases in the Press passage walkable, the pin incompressible and at least adhesion-reducing be is layered and the pin has a recess, which with one of the recess protruding disc is filled.

Through the protruding disc from the recess, the Vorge mischs an additional recess pressed into the depression pressed by the pin. This "hollow in the hollow" leads to the subsequent filling process, in particular pouring, the cavity to a significantly improved adhesion of the core in the cavity of the mold body.

The recess in the pin and thus also the disc inserted into the recess can have different footprints. So it is possible to have rectangular or square ones To make indentations and filler disks in the pin. It is within the scope of the present However, the invention is preferred when the recess has the shape of a circle, an ellipse or has a geometrically similar shape.

Depending on the dimension of the pin, the dimension of the recess in the pin and the dimension of the disc that is fitted into the recess vary. Preferred tablet punches have depressions with a depth of 0.1 to 5 mm, preferably from 0.2 to 3 mm and in particular from 0.3 to 1.5 mm, it being particularly it is preferred that the disc be at least 0.1 mm, preferably at least 0.3 mm the recess protrudes.

The disk fitted into the recess consists in preferred embodiments of the present invention made of a reversibly deformable material with a hardness of 40 up to 99 Shore A according to DIN 53505, preferably made of polyurethane, for example in particular Vulkollan, or PVC, for example in particular Mipolam. The mentioned materials who described in detail below.

The mostly powdery or fine-grained material to be compressed into tablets is if not particularly complex and production-hindering arrangements for a special distribution can be made, when filling in the press die approximately evenly distributed. This has the consequence that the material in the places where the profile of the embossing elements has the highest elevations, must be compressed the most. Whether probably the material to be pressed will experience the highest pressure peaks due to a movement in Tried to evade the direction of the less stressed areas, step into the Areas of the highest profile elevations also have the highest specific surface pressures on.

If the profile of the embossing element consists of a flat surface, for example the base area surface that surrounds an ellipsoidal pin, for example, are the highest surfaces loads on the pin, and on it in the ellipsoidal dome to be expected. In the field of At the top, the surface has only a very small angle of inclination in relation to the base surface no. By definition, these angles of inclination increase in the direction of the ellipsoid base and are greatest at the transition to the surrounding area. The pressing force acts lower right to the base plane and to the surface element in the center of the ellipsoidal dome. As the distance from this center element increases, the pressing force increases mend inclined surface directed, so that the pressing force in a correspondingly smaller, force component perpendicular to the respective surface element and one again is divided by force component directed perpendicular to it. These transverse forces act quasi tangential. The force components perpendicular to the normal force are a measure for the shear and abrasion forces that act at the interface between the pin and to be pressed send material. Among other things, because of these abrasive forces, the ellipsoid Shaped pins be made of a very hard, incompressible material.

The tendency of the material to be pressed to adhere to the surface of the ram is determined, among other things, by the specific surface pressures between the one to be pressed Material and the stamp surface as well as determined by the surface structure. Has the Surface of the pressing or tableting punch, for example, friction-reducing or lubricating or sliding properties, this prevents the tendency to stick or at least diminished.

As already mentioned, the pressing forces are directed perpendicular to the flat base. There the flat base represents the lowest height in the profile of the embossing element is in the This area gives the lowest compression of the material to be pressed. this leads to also that lower surface pressures are to be expected in the area of the base area than in the area of the upwardly curved pin. For these reasons, the material must be the The base area must also not be incompressible, especially since only normal from the print geometry forces are to be expected.

The structure of beds made of powdery or finely crystalline substances is true to be considered uniform in terms of larger areas or volumes, in the microbe rich but very different. Due to these different in the micro range Density ratios become those on the surface of the base material uniform pressing forces different resistances of the material to be pressed opposite. This leads to the fact that at points spaced apart in the micro-range Surface different specific pressures and therefore with compressible material of the base element on slightly different deformations of the material step. This phenomenon, referred to here as fulling, has the emergence of different things normal and transverse forces on the material surface result, whereby the inclination for adhering material to the surface of the embossing element in the area of the base area che is prevented or at least largely reduced.

A tablet punch, the embossing element of which is designed in the form described, is shown in FIG advantageously prevents sticking or at least reduces adhesion. With a sol Chen press tools can have long tool life and flawless tablet surfaces can be achieved.

In one embodiment, in which the embossing element of the tabletting punch does not extend from the side the base area should be limited, and this should be of a substantially uniform, Incompressible marginal strips are surrounded, repercussions of the compression and Deformation on the inner wall of the die affects the compressible base area closed. An outwardly rising bevel of the edge strip causes in advantageously a clean material distribution in the die and stabilization the tablet structure.

Very special advantages in the manufacture of the tablet stamp and the stability of the pressing tool are guaranteed in one embodiment in which the embossing element consists of several individual parts. Appropriately, the scope and cut the individual parts are oriented towards the different materials or material requirements. So the individual production of the ellipsoidal pin from incompressible and at the Outer surface of at least an adhesion-reducing coated material, a plate shaped element made of walkable material for the base and an annular Element made of incompressible material for the edge strip an advantageous delimitation for the design of the individual parts, which differ because of their different materials offers.

As described above, the coating of the pin must be hard and resistant at the same time be able to withstand high surface loads, but also have a minimum of friction have changing or lubricating property. For this purpose, nickel-containing surfaces have been used coatings have proven to be very suitable in which the finest PTFE particles (Teflon) are included. These give the coating an anti-sticking and material seizure contraceptive properties. Alternatively, an embodiment for the ad Adhesion-reducing coating proven in which the base coating material takes place made of nickel from a nickel-phosphorus alloy.

As a further alternative for surface coating with at least adhesion reducing effect, which also otherwise meets the requirements for hardness and durability A coating made of graphite containing diamond particles has proven to be sufficient lasts. The surface of the pin is coated with a graphite layer, which as lubricating or sliding are known, and here at the same time as a binder for the fixie tion of diamond particles is used, which in turn ver the required hardness of the surface Rent. Experiments with these surface coatings of the pin have shown that No material build-up to be observed even with very long tool life was. It is therefore preferred that the at least adhesion-reducing coating in the consists essentially of carbon.

The adhesion-preventing or at least adhesion or adhesion-reducing effect of the walkable material for the formation of the base area has been described above. In Tests have shown that, for example, with the polyurethane material Vulkollan or the PVC material Mipolam, very good results could be achieved. About a Set times of several thousand pressings, no adherence whatsoever was found on the ground surface material determined.

The mentioned and other advantages are clearly illustrated in the description of embodiments shown in the accompanying drawing. In it shows

Fig. 1 shows the cross section through a tableting punches;

FIG. 2 shows the plan view of a tabletting punch according to FIG. 1; FIG.

Fig. 3 is a schematic exploded view of a disassembled parts are in single tableting punch whose contours of the punch of FIG. 1 similarly, and

Fig. 4 schematically shows the sectional side view of a well tablet which was produced with a proposed tabletting punch.

In Fig. 1, the tabletting punch 1 is shown in a sectional side view. The illustrated embodiment has a pin 4 in the form of a semi- ellipsoid and a substantially rectangular base 3 . This clearly shows the base 3 , the edge strip 5 arranged around the base 3 , and the pin 4 surrounded by the base, which is designed here as a half ellipsoid. A surface coating 12 can be seen on the pin 4 . The pin 4 also has a recess into which a disk 14 protruding from the recess is fitted. The Tablettierstem pel 1 has adjustment and centering holes 7 in the punch body and shaft, which allow its exact alignment with respect to the tableting press and the complementary tabletting tools. The illustrated embodiment of the tabletting punch 1 is an upper punch. This corresponds to the preferred embodiment. Edge strip 5 , base 3 , pin 4 and disc 14 , which together form the embossing element 2 , are in contact with the material to be pressed during the pressing process. In order to avoid or at least reduce adhesion of the material to be pressed, the surface of the pin 4 is coated with a non-stick layer 12.

On the base 3 and preferably also on the surface of the disc 14 , the material to be pressed is prevented from sticking to the fact that the material of the base is made of a very firm and smooth, but workable material. Suitable materials for this are, for example, polyurethane, preferably Vulkollan, and PVC materials, for example Mipolam. The material of the edge strip 5 is incompressible and the beveled surface is very smooth. Their adhesion-preventing design can be supported, for example, by hard chrome plating or by a surface coating with Ni-PTFE, Ni-P-PTFE or C-diamond.

The layer 12 with which the surface of the pin 4 and possibly the edge strip 5 is coated for the purpose of preventing or at least reducing the adhesion of material to be pressed must have at least two properties. It must be hard and incompressible, similar to the base material of the pin, and on the other hand support or facilitate the sliding between the pin and the material to be pressed. These sliding properties are particularly important to avoid buildup, so that the transverse forces acting almost tangentially due to the tendency towards the alignment of the pressing force support or at least not hinder a material movement directed in the direction of these transverse forces. These relative movements in the micro range counteract the adhesion of the material to be pressed. The alternative coating of the edge strip 5 with the layer 12 is indicated by the dashed illustration.

FIG. 2 shows the top view of the tabletting punch 1 according to FIG. 1. Clearly visible is the substantially rectangular, but rounded shape of the embossing element 2 , which this consists of edge strips 5 , enclosed base 3 and surrounded by a pin 4 with a seated in a recess in the pin and protruding from the pin Disc 14 is formed. The circular outline of the press die base can be seen around the embossing element 2.

FIG. 3 shows in schematic form how a tabletting punch 1 , which is similar to the tableting pen shown in FIGS. 1 and 2, can be broken down into individual parts. In the schematically illustrated embodiment, a mushroom-shaped part with a head in the form of the ellipsoidal pin 4 with a recess in which the disc 14 can be attached and an annular layer 6 , the uncovered outer surfaces of which form the base 3 , and a frame element, its outer boundary is formed by a wall, the upper part of which corresponds to the edge strip 5 , the individual parts. These individual parts, shown here in exploded form, form the tabletting punch 1 with the embossing element 2 when assembled.

This embodiment is designed so that the parts to which different surface requirements are made, are each formed as a single part with different materials or material processing. In this way, the different requirement profiles for the various parts of the embossing element 2 can be presented in a simple and technically clearly manageable form. The items are locked together in the assembled form, so that the immovability and stability of the tabletting punch 1 is guaranteed.

In Fig. 4, the cross-section of a well tablet or a well tab 8 is shown in a very simplified manner. The hollow tab 8 shown here is made of two different materials which were pressed separately from one another and which are clearly distinguishable from one another in the two layers, the lower layer 11 and the upper layer 10. Since both layers 10 , 11 with the same pressing tool, that is, in the same die, in which the material of the lower layer 11 and the material of the upper layer 10 was filled one after the other before the second pressing cycle, and are made with the same tableting punch 1 , have both layers 10 , 11 have identical lateral and upper boundary contours. The facets 13 formed by the edge strip 5 of the embossing element 2 and a corresponding profiling of the die (not shown) can be clearly seen.

It is very clear at the upper limit contour that the compression of the material to be pressed, which is filled into the press die at an approximately uniform height, is very different according to the profile of the embossing element 2. The lowest compression occurs in the area of the base 3 . In this area, the compressive forces occur perpendicular to the surface. A greater compression takes place in the area of the edge strip 5 , the pin 4 and the protruding disc 14 from the pin, the compression being greater, the further the parts of the embossing element 2 protrude in the direction of the pressing force. The pressing force is only exactly in the center of the disc seated in the pin or in the center of the trough 9 formed by the pin 4 and the disc 14 protruding from it in the material to be pressed exactly perpendicular to the material to be pressed. In all other areas, the pressing force is divided into a normal force and a transverse force component perpendicular to the beveled surface. This is oriented more or less tangentially and causes a certain shear stress on the material to be pressed. When assembling the Mul dentabs 8 , the trough 9 is filled with a third substance after the pressing process, which is filled in either pasty or liquid or melted and solidifies or solidifies in the trough.

The inventive design of the tabletting punch, the adhesion of the filled "core" in the well significantly improved, as the following examples show.

Examples

With the help of a tabletting stamp according to the teaching of the earlier German patent application DE 198 38 103.4, Muldentabs V were produced with an elliptical depression, wel che had the following dimensions:

Length: 36 mm Broad: 26 mm Height: 18 mm Depth of the hollow: 5 mm Half-axis lengths of the trough: a = 8.3 mm b = 11.5 mm

For comparison, hollow tabs E according to the invention were produced by compression were obtained with a press tool in which a circular, 1 mm deep hole with a diameter of 5 mm was drilled, the one with a 2 mm thick Mipolan disc was filled. The tray tabs E according to the invention thus contained Another cylindrical recess in the ellipsoidal depression.

The composition of the compressed premixes and the physical parameters contribute the compression were identical for both series of molded bodies. Both moldings were filled with 1 ml of paraffin (mp. 66-67 ° C) by the molten paraffin with a Tem temperature of 75 ° C was poured into the room temperature moldings.

While the solidified paraffin core could easily be pushed out of the comparative moldings V with the thumb, this was not the case with the moldings E according to the invention. To test the mechanical stability, 20 tabs were dropped one after the other from a height of 40 cm onto a flat surface, the tablet top with the filled cavity pointing a) downwards, b) to the side and c) upwards. After the impact, an assessment was made of how many tabs the filling had detached from the molding. The results of these drop tests are shown in the following table:

List of reference symbols

1

Tableting punches

2

Embossing element

3rd

Floor space

4th

Cones

5

Margins

6th

annular position

7th

Adjustment and centering hole

8th

Trough tab

9

trough

10

upper layer

11

lower layer

12th

Surface coating

13th

facet

14th

disc

Claims (21)

1. Tableting stamp, the embossing element ( 2 ) of which has a pin ( 4 ) surrounded by a flat base surface ( 3 ), the base surface ( 3 ) being walkable in the pressing cycle and the pin ( 4 ) being incompressible and at least coated to reduce adhesion and having a recess, which is filled with a protruding from the recess the disc ( 14). 2. Tableting stamp according to claim 1, characterized in that the recess has the shape of a circle, an ellipse or a geometrically similar shape. 3. Tableting stamp according to claim 1 or 2, characterized in that the Ver deepening a depth of 0.1 to 5 mm, preferably 0.2 to 3 mm and in particular which has from 0.3 to 1.5 mm. 4. Tableting punch according to one of claims 1 to 3, characterized in that the disc ( 14 ) protrudes from the recess at least 0.1 mm, preferably at least 0.3 mm. 5. Tableting stamp according to one of claims 1 to 4, characterized in that the disc ( 14 ) made of a reversibly deformable material with a hardness of 40 to 99 Shore A according to DIN 53505, preferably made of polyurethane, for example in particular special Vulkollan, or PVC , for example in particular Mipolam. 6. Tableting stamp according to one of claims 1 to 5, characterized in that the cone has the shape of a semi-ellipsoid, a segment of a sphere or a geome has a trisch similar shape. 7. Tableting stamp according to one of claims 1 to 6, characterized in that the cone has a volume of 0.5 to 5 ml, preferably 0.6 to 3 ml, especially before added 0.8 to 2 ml. 8. Tableting stamp according to one of claims 1 to 7, characterized in that the base ( 3 ) is surrounded by an incompressible, substantially uniform edge strip ( 5 ). 9. Tableting stamp according to claim 8, characterized in that the edge strip ( 5 ) lies on the inside at the level of the upper edge of the base and is inclined towards the outside. 10. Tableting stamp according to one of claims 1 to 9, characterized in that the embossing element ( 2 ) consists of several individual parts which are joined together fixier bar. 11. Tableting stamp according to one of claims 1 to 10, characterized in that the base ( 3 ) is substantially rectangular and preferably has rounded corners. 12. Tableting stamp according to one of claims 1 to 11, characterized in that the base ( 3 ) is substantially round. 13. Tableting punch according to one of claims 1 to 12, characterized in that the tableting punch ( 1 ) is the upper punch. 14. Tableting stamp according to one of claims 1 to 13, characterized in that that the at least adhesion-reducing coating consists of Ni-PTFE. 15. Tableting stamp according to one of claims 1 to 14, characterized in that that the at least adhesion-reducing coating consists essentially of Koh made of fuel. 16. Tableting stamp according to one of claims 1 to 15, characterized in that the base ( 3 ) consists of a reversibly deformable material with a hardness of 40 to 99 Shore A according to DIN 53505. 17. Tableting stamp according to claim 16, characterized in that the Grundflä surface ( 3 ) consists of polyurethane, for example in particular Vulkollan, or PVC, for example in particular Mipolam. 18. Tableting stamp according to one of claims 11 to 17, characterized in that the base area ( 3 ) including the edge strips is 5 to 30 cm ² , preferably 5 to 20 cm ² , particularly preferably 8 to 12 cm ² . 19. Tableting stamp according to one of claims 11, 13 to 18, characterized in that the substantially rectangular base ( 3 ) including the edge strips the dimensions of about 36 × 26 mm and the ellipsoid of the pin surrounding it ( 4 ) about the half-axis lengths of a = 8.3, b = 11.5 and c = 5 mm. 20. Tableting stamp according to one of claims 12 to 18, characterized in that the circular base ( 3 ) including the edge strips has a diameter of 34 mm and the pin ( 4 ) in the form of a spherical segment, the semiaxis lengths a = b = 11 mm and c = 5 mm has. 21. Washing, rinsing, cleaning or auxiliary washing agent tablet, produced with a Ta Bletting stamp according to one of Claims 1 to 21.