DETERGENT TABLETS HAVING A CONVEX STRUCTURE

Abstract

 The present invention refers to detergent tablets comprising a pressed body having an upper and a lower surface wherein at least one of the upper or lower surface being convexly curved.

Description

[0001] The present invention refers to detergent tablets comprising a pressed body having an upper and a lower surface wherein at least one of the upper or lower surface being convexly curved.

[0002] Detergent tablets like e.g. automatic dishwashing detergent tablets or laundry detergent tablets in Europe commonly are provided in form of bars or pressed bodies having an upper and a lower surface, four 90° angels and two longer and two shorter sides. Accordingly, considered in a top view they have a rectangular form fitting perfectly in an applied dosing chamber of e.g. automatic dishwashing machines or laundry machines in the European market.

[0003] Furthermore, it is also very common to separate particular ingredients of a detergent tablet by providing tablets with more than one phase, wherein the content / compositions of the phases differ from each other. One example of tablets having more than one phase are tablets comprising a pressed body having a mould or cavity on at least one surface which is filled with either a further pressed body or with a gel, solidified liquid, hot melt material or any suitable / desired composition. Usually such cavities are prepared in at least one surface of the body during the pressing procedure.

[0004] To press the detergent composition in form of tablets a detergent composition comprising ingredients not being sensitive for pressure are filled in a pressing mould and then pressed by applying a heading tool with a suitable force. The detergent composition usually is used in powder or granulate form. Ingredients sensitive for pressure or interacting with other composition ingredients are combined with the pressed body after its preparation, e.g. by filling them in a pre-formed cavity. To provide such a cavity during the pressing procedure a heading tool having a protrusion / embossment in the form of the desired cavity is used.

[0005] Since usually the detergent composition is filled into the pressing mould in an evenly distributed manner, the portion of the composition located in the area under the protrusion of the heading tool receives a noticeably higher pressure compared to the remainder of the composition. Thus, the part of the pressed tablet located under the prepared cavity has a noticably higher density than the remainder of the pressed body. This results in several problems, e.g. a tendency to form cracks in the area under the cavity or in different dissolution or different disintegration of the parts of the tablet having different density.

[0006] The object of the present invention was to provide a modern detergent in form of a unit dose allowing the provision of separate phases, wherein each of the phases of said tablet dissolve or disintegrate essentially uniformly.

[0007] This object is met by a detergent tablet as defined in claim 1, comprising a pressed body having at least a convexly curved upper surface with a cavity. Preferred embodiments are represented by the dependent claims.

[0008] The tablet of the present invention comprises a pressed body having (a) an underside having a lower surface (1), (b) an upper side having an upper surface (2), (c) a lateral surface connecting the underside with the upper side, which comprises (i) side surfaces (3, 3'), as well as (ii) a front side (4) and a rear side (4'). According to the present invention, the lower surface (1) of the tablet is flat and the upper surface (2) is convexly curved along the side surfaces (3, 3') and/or along the front (4) and rear (4') side. The tablet of the present invention further comprises (d) a cavity (5) in the upper surface (2) in the thickest part (6) of the pressed body.

[0009] The term "lateral surface" in the present invention refers to the sides of the pressed body which connects the underside and the upper side of said pressed body by edges. Said lateral surface comprises side surfaces (3, 3') as well as a front (4) and a rear side (4').

[0010] According to the present invention, the side surfaces (3, 3') are opposite to each other and the surfaces of the front (4) and rear (4') side are opposite to each other, respectively. The term "side surfaces" refers to the surfaces encompassing between the front (4) and the rear (4') sides.

[0011] "Convexly curved" means that the upper surface (2) of the pressed body is outwardly curved with reference to the lower surface (1) of the underside.

[0012] According to the present invention the term "cavity" refers to a space within the upper side of the pressed body.

[0013] Said body comprises or consists of a pressed detergent composition. Said detergent composition can be represented by a uniform detergent composition having only one phase of uniformly divided detergent ingredients, or can be represented by more than one phase, e.g. two, three, four or more than four phases, each representing compositions comprising (at least one) detergent ingredient(s), however in combinations differing from each other. At least one further phase / further phases of the tablet is / are provided by filling the cavity (5) of the pressed body with at least one further detergent ingredient, or by placing said at least one further ingredient into said cavity (5).

[0014] The cavity (5) is provided in the convexly curved upper surface (2) of the pressed body, preferably in the area of the highest height (6), thus, in the area where the pressed body has the greatest thickness (6), considered in a side view. Placement of the cavity (5) in said area (6) allows the formation of said cavity (5) without generation of a disproportional density of the pressed body below said cavity (5).

[0015] The convexly shaped surface (2) of the pressed body is obtainable by using a heading tool (11) having a concavely shaped inner surface (12) with a protrusion / embossment (13) at its deepest point / area. Using such a heading tool (11) during the pressing process has the effect that the detergent composition, initially evenly divided in the pressing mould (10), comes in contact with the heading tool (11) at first at the edges of the heading tool (11) and - due to the free-flowing character of the detergent - it is pushed in direction of the recess (14) of the heading tool, except the area of the protrusion / embossment (13). The full pressure power of the heading tool (11) is only applied when the whole space between the heading tool and the forming mould (10) is filled with the detergent powder / granulate. Therefore, the area under the protrusion / embossment (13) is not or only slightly more densified by application of the pressure power than the remainder of the pressed body.

[0016] According to the present invention, the pressed body comprises edges. With "edges" according to the present application the contact points or contact areas are meant connecting the surfaces of the pressed body to each other, in particular the lateral surfaces (3, 3', 4, 4') with the upper (2) and lower (1) surface. In particular the term "edges" is used for the area encompassing the outer most 0,5 to 3 mm or 1 to 2mm of each of the surfaces of the pressed body. The lateral surfaces (3, 3', 4, 4') of the pressed body can all have the same size or length, however, it is preferred that the body comprises two sides which are longer than the other sides. Thus, in a preferred embodiment the pressed body has side surfaces (3, 3') and a front side (4) and a rear side (4'), wherein the side surfaces (3, 3') differ in their length from the front (4) and the rear (4') side. Preferably the side surfaces (3, 3') are longer than the front (4) and the rear (4') side resulting in longitudinal surfaces (3, 3'). According to the invention it is preferred that the lower surface (1) of the tablet preferably is flat, whereas the upper surface (2) is convexly curved, either along the side surfaces (3, 3') of the pressed body, or along the front side (4) and the rear side (4'), or along the side surfaces (3, 3') as well as along the front (4) and the rear (4') side (see Figure 2(A) and 2(B)).

[0017] Accordingly, the angles connecting the lower surface (1) to the lateral surfaces (3, 3', 4, 4') are essentially 90° (lower surface to each of the side surfaces), whereas at least two of the lateral surfaces (3, 3', 4, 4') are connected to the upper surface (2) by angles having more than 90°, preferably between 91° and 150°, between 92° and 135° or between 93 and 120°.

[0018] In any case the edges can be rounded, however, the surface of a side (3, 3', 4, 4') forms an according angle to the surface of the lower (1) or to the upper (2) surface (if extrapolated), respectively. The angle between the lateral surfaces (3, 3', 4, 4') and the upper surface (2) is measured in the "raising" area of the upper surface (2), thus, in the area where the convex surface "raises" and the pressed body becomes thicker than at the lateral surfaces (3, 3', 4, 4') (see Figure 1). According to the invention at least two of the angles between a lateral surface (3, 3', 4, 4') and the upper surface (2) are more than 90°, these might be the angles between the side surfaces 3 and 3' and the upper surface (2), or the angles between the front and rear sides 4 and 4' and the upper surface (2). It is, however, also according to the invention that all the angles between the lateral surfaces (3, 3', 4, 4') and the upper surface (2) are more than 90°, wherein they may represent equal angels, or they may differ from each other. It is preferred that at least two angles have the same value, e.g. the angle between the front side (4) and the upper surface (2) is the same as the angle between the rear surface (4') and the upper surface (2), wherein the angle of the side surfaces (3, 3') with the upper surface (2) might be the same as well, however, can differ from the angle of the front / rear surface (4, 4') with the upper surface (2).The lateral surfaces (3, 3', 4, 4') can have the same or different length, wherein in a preferred embodiment they have different length e.g. the two parallel longitudinal side surfaces (3, 3') are longer than the front (4) and the rear (4') side.

[0019] Considered from the side surfaces (3, 3'), the pressed body may have an upper surface (2) which is convexly curved along the side surfaces (3, 3'), whereas the upper surface (2) is flat and plane-parallel to the lower surface (1) along the front side (4) and rear side (4') (see Figure 1(C) and 1(D) and Figure 4(B) and 4(C)). Accordingly, if the upper surface (2) is flat and plane-parallel to the lower surface (1) viewed from the front side (4) as well as rear side (4'), the angles between the front and rear sides 4 and 4' and the upper surface (2) represent equal angles and are more than 90 °, preferably between 91° and 150°, between 92° and 135° or between 93 and 120°. However, the angles between the side surfaces 3 and 3' and the upper surface (2) are then essentially 90 ° which means 89 to 91 °, but preferably 90 ° (see Figure 1 and 4). A similar approach is possible, wherein the pressed body might have an upper surface (2) which is convexly curved along the front side (4) and rear side (4'), whereas the upper surface (2) is flat and plane-parallel to the lower surface (1) along the side surfaces (3, 3'). If the upper surface (2) is flat and plane-parallel to the lower surface (1) along the side surfaces (3, 3') the angles between the side surfaces 3 and 3' and the upper surface (2) represent equal angles and are more than 90 °, preferably between 91° and 150°, between 92° and 135° or between 93 and 120°,whereas the angles between the front side (4) as well as rear side (4') and the upper surface (2) are then essentially 90 °.Moreover, considering from the side surfaces (3, 3') the edge of the upper surface (2) to the side surfaces (3, 3') of the pressed tablet might be convexly curved along the side surfaces (3, 3'), whereas the edges of the upper surface (2) to the front side (4) and rear side (4') are concavely curved along the front side (4) and rear side (4') (see Figure 1(C) and 1(D)). A similar approach is possible, wherein the edges of the upper surface (2) the side surfaces (3, 3') are concavely curved along the side surfaces (3, 3'), whereas the edges of the upper surface (2) to the front side (4) and rear side (4') are convexly curved along the front side (4) and rear side (4'). "Concavely curved" along at least two opposite lateral surfaces (3 and 3', or 4 and 4') means that the side surfaces 3 and 3' are higher than the front 4 and rear 4' side or vice versa, resulting that the edge of the upper surface (2) to the lateral sides (3, 3', 4, 4') is curved inwardly along the side surfaces (3, 3') or along the front side (4) and rear side (4') (see Figure 1(D) and Figure 4(C)).

[0020] Herein, the upper surface (2) of the pressed tablet is convexly curved along the side surfaces (3, 3') and/or convexly curved along the front and rear side (4, 4') resulting in a convex curvature (7) of the upper surface (2) of the pressed body. The convex curvature (7) of the pressed body is characterized in that the lateral surfaces (3, 3', 4, 4') have a lower height than the area of the thickest part (6) of the pressed body. Accordingly, there may be a height difference between the thickest part (6) of the pressed body and the edge connecting the upper surface (2) with the side surfaces 3 and 3' and/or a height difference between the thickest part (6) of the pressed body and the edge connecting the upper surface (2) with the front (4) and rear (4') side. Said height difference preferably is 1.5 to 15 mm, more preferably 2 to 12 mm, even more preferably 3 to 10 mm, most preferably 4 to 8 mm. Or said height difference preferably is 1.0 to 6.0 mm, more preferably 1.1 to 5.0 mm, even more preferably 1.2 to 4.0 mm, most preferably 1.4 to 3.5 mm.

[0021] According to the present invention, the convex curvature (7) of the upper surface (2) may be flattened in the thickest part (6) of the pressed body forming a plateau (8) which is plane-parallel to the lower surface (1) (see Figures 1 and 3). Furthermore, the upper surface (2) comprises the cavity (5) in at least a part of the plane-parallel plateau (8) still enabling the formation of said cavity (6) without generation of a disproportional density of the pressed body below said cavity (5). Said plateau (8) which is plane-parallel to the lower surface (1) preferably spans 10 to 40 percent of the upper surface (2) of the pressed body, more preferably 15 to 35 percent, and most preferably 20 to 30 percent. Said plateau (8) which is plane-parallel to the lower surface (1) and includes the area where the cavity (5) is situated preferably spans 15 to 80 percent of the upper surface (2) of the pressed body, more preferably 20 to 70 percent, even more preferably 25 to 65 percent and most preferably 30 to 40 percent. According to the present invention, the plateau (8) may span the thickest part (6) of the pressed body as it can be seen in Figure 1(C).

[0022] The pressed body of the present invention in a top view may have a rectangular or square shape, optionally with rounded edges (see Figures 1 to 4). However, the pressed body may also be round, oval or elliptic, or it might represent a polygon with more than 4 side surfaces, preferably 6 or more, particularly preferred 8 or 10 side surfaces. Moreover, the shape of the body of the present invention may have any shape between rectangular and elliptic. The edges of the pressed body may be rounded or sloped according to the present invention. Preferably at least the edges connecting the upper side with the lateral surface (3, 3', 4, 4') are rounded or sloped (see Figure 1). The tablet of the present invention comprises a pressed body with a preferred weight of 8 to 70 g, more preferred weight of 10 to 45 g and most preferred weight of 11 to 30 g. Further particularly preferred weights of the pressed body are 12 to 28 g, 13 to 26 g, 14 to 25 g, 15 to 24 g and 15 to 22 g. Said pressed body may be 22 to 60 mm long and 16 to 32 mm wide, preferably 24 to 56 mm long and 18 to 31 mm wide, more preferably 27 to 53 mm long and 20 to 30 mm wide, even more preferably 30 to 48 mm long and 21 to 30 mm wide, most preferably 32 to 45 mm long and 22 to 29 mm wide and particular preferably 34 to 40 mm long and 23 to 28 mm wide. Said pressed body may have a lower surface (1) with a diameter or diagonal of 60 to 56 mm, or of 55 to 50 mm, or of 49 to 45 mm, or of 44 to 40 mm, or of 39 to 35 mm. Moreover, the thickest part (6) of the pressed body of the present invention may be 8 to 30 mm high, preferably 8 to 28 mm high, more preferably 9 to 26 mm high, even more preferably 9 to 24 mm high, most preferably 10 to 22 mm high and particular preferably 10 to 20 mm high.

[0023] The cavity (5) in a top view according to the present invention may have a round, oval, elliptic, rectangular, square or polygonal shape. Said cavity (5) preferably spans 10 to 60 percent of the upper surface (2) of the pressed body, more preferably 15 to 55 percent, even more preferably 20 to 50 percent, even more preferably 25 to 45 percent and most preferably 25 to 35 percent, or 30 to 40 percent, or 35 to 45 percent. The width of the cavity (5) in the pressed body may be 10 to 20 mm, preferably 12 to 18 mm, and more preferably 14 to 16 mm.

[0024] Moreover, the cavity (5) of the present invention may span 3 to 60 percent of the depth of the thickest part (6) of the pressed body, preferably 5 to 55 percent, more preferably 8 to 50 percent, even more preferably 10 to 45 percent, most preferably 12 to 40 percent and particular preferably 15 to 35 percent. The depth (9) of said cavity is preferably 1 to 15 mm deep, more preferably 2 to 12 mm, even more preferably 3 to 10 mm, most preferably 4 to 8 mm and particular preferably 4 to 6 mm.

[0025] The composition serving as a basis for the detergent tablets of the present invention is not limiting the invention, since it is not essential which type of detergent composition is representing the tablet. Any detergent composition which can be provided in form of a tablet can be used according to the invention.

[0026] The tablets of the present invention can be prepared of any of the known detergent compositions. According to the present invention, the detergent composition of the pressed body might comprise an automatic dishwashing composition, a laundry detergent composition, a bleaching composition, a water softening composition, or a stain removal composition, but is preferably an automatic dishwashing composition.

[0027] The detergent composition comprises at least one active detergent component but preferably comprises a mixture of more than one active detergent components. Suitable active detergent components are described hereinafter. Preferred active detergent components include builder compound(s), surfactant(s), bleaching agent(s), bleach activator(s), bleach catalyst(s), optical brightener(s), enzyme(s) and an alkalinity source(s).

[0028] Builder components are very well-known in the art. The invention is not restricted to particular builder types. Examples of builder compounds can be independently selected from the group comprising inorganic non-phosphate builders including, but are not limited to, phosphonates, silicates, carbonates, sulphates, citrate, citric acid and aluminosilicates; organic builders including, but are not limited to, a wide variety of (poly)carboxylated compounds and phosphate builders including, but are not limited to, various alkali metal phosphates such as tripolyphosphate, pyrophosphate, orthophosphate, etc.

[0029] The surfactant according to the present invention can be independently selected from nonionic, anionic, cationic and amphoteric surfactants. Examples are given by the group comprising non-ionic surfactants with ethylene oxide and/or propylene oxide and/or butylene oxide groups; anionic surfactants, with carboxylate, sulphonate, sulphate or phosphate end groups; cationic surfactants; amphoteric surfactants, such as betaines, glycinates, amino propionates; and polyalkene glycols, such as polyethylene glycol, without being restricted to the mentioned.

[0030] Bleaching agents that can be used in detergent compositions include, but are not limited to, active chlor compounds; inorganic peroxygen compounds or; organic peracids. Examples are sodium percarbonate, sodium perborate monohydrate, sodium perborate tetrahydrate, hydrogen peroxide, hydrogen peroxide based compounds, peroxymonosulphate, ephthalimid-peroxo-capronic acid, benzoyl peroxide, sodium hypochlorite, sodium dichloroisocyanurate, etc., without being limited to the mentioned.

[0031] Bleaching activators that can be used in detergent compositions include, but are not limited to, tetraacetylethylenediamine (TAED), sodium nonanoyloxybenzene sulphonate (NOBS), acetyl caprolactone, and N-methyl morpholinium acetonitrile and salts thereof (such as Sokalan BMG from BASF).

[0032] Bleaching catalysts that can be used in detergent compositions are intensively described in the state of the art. These include, but are not limited to, a complex of manganese(IV) with 1,4,7-trimethyl-1,4,7-triazacyclononane (MnMeTACN), tris[2-(salicylideneamino)ethyl]amine manganese(III), etc.

[0033] Optical brighteners that can be used in detergent compositions are intensively described in the state of the art and include, but are not limited to, stilbene-, pyrazolin-, cumarin-, benzoxazol-, naphthalimide-, distyrilbiphenyl sulphonate-, pyren-, methyl umbelliferon- and dihydroxyquinolin-derivates.

[0034] The enzymes that can be used in detergent compositions include, but are not limited to, proteases, amylases, lipases, cellulases, mannanase, peroxidase, oxidase, xylanase, pullulanase, glucanase, pectinase, cutinase, hemicellulases, glucoamylases, phospholipases, esterases, keratanases, reductases, phenoloxidases, lipoxygenases, ligninases, tannases, pentosanases, malanases, arabinosidases, hyaluronidase, chondroitinase, laccase or mixtures thereof. These enzymes are known to the skilled artisans and can be used in common amounts.

[0035] The detergent composition of the present invention may optionally comprise one or more dyes. The dye is used to color the detergent, parts of the detergent or speckles in the detergent. This will make the product more attractive to the consumer.

[0036] The detergent composition of the present invention may optionally comprise one or more perfumes. The perfume(s) is added to the detergent to improve the sensorial properties of the product or of the machine load after cleaning. The perfume can be added to the detergent as a liquid, paste or as a co-granulate with a carrier material. To improve the stability of the perfume it can be e.g. used in an encapsulated form or as a complex like for example a perfume-cyclodextrine complex. Also perfumes that have a deodorizing effect can be applied. These perfumes encapsulate malodors by binding to their sulfur groups.

[0037] The active detergent components are preferably prepared in particulate form (i. e. powder or granular form) and may be prepared by any known method, for example conventional spray drying, granulation, pelleting or agglomeration.

[0038] According to the present invention, the cavity (5) of the pressed body may further be filled with a further (part of a) detergent composition known in the art. Said (further part of the) detergent composition may comprise ingredients of an automatic dishwashing composition, a laundry detergent composition, a bleaching composition, a water softening composition, or a stain removal composition, preferably ingredients of an automatic dishwashing composition. Herein, the component(s) of the detergent composition which is/are filled in the cavity (5) may be the same as the detergent composition of the pressed body or may preferably be different. Preferably, the cavity (5) is filled with component(s) of a detergent composition differing in at least one ingredient from the composition of the pressed body. The cavity may be filled with the component(s) of a detergent composition in the form of (i) a further pressed body, shaped to fit into the cavity, (ii) a hot melt material, (iii) a gel, (iv) a packaged liquid or powder, (v) a sintered material, or any combination of (i) to (v).

[0039] The active detergent components of a detergent composition may be separated from one another by having one or more compatible components contained in the compressed portion and one or more compatible components contained in a non-compressed portion of the tablet. Examples for components restricting processability of the detergent composition, e.g. ability to be compressed are surfactants. Examples of components that may interact and therefore preferably are separated include bleaching agents, bleach activators or catalysts and enzymes; bleaching agents and bleach catalysts or activators; bleaching agents and surfactants; alkalinity sources and enzymes.

[0040] The present pressed body of the tablet results in stable tablets which are easy to process and to handle and simultaneously provide fast and homogenous disintegration. In particular, the present tablets have less tendency to brake and can be placed in the dosing chambers of any common dishwashing and laundry machine.

[0041] The tablets of the present invention can be wrapped by any film, foil or paper, as presently known in the art. Preferably, the tablets of the present invention are wrapped in water soluble or dispersable film based on polyvinyl alcohol, copolymer of polyvinyl alcohol and poly acetate, casein, or water insoluble film based on polypropylene, biaxially oriented polypropylene or oriented polypropylene. Due to their essentially unchanged width and thickness compared to up to now commonly produced tablets the wrapping equipment and wrapping machines do nothave to be changed significantly.

[0042] Furthermore, the tablets of the present invention can be coated with any of the known coating compositions for detergent tablets. Such coating compositions are extensively described in the state of the art. Which type of such coatings used is not limiting the invention.

[0043] The present invention further relates to a method to prepare a tablet of a detergent composition comprising a pressed body as described herein. The method of the present invention comprises pressing a particulate detergent composition in a pressing mould having at least one concave surface with an embossment having a shape and dimensions as defined above for the cavity (5). Said pressing mould comprises a lower punch (15) and an upper punch (11). The lower (15) or the upper (11) punch has an inner surface (12) which is concavely shaped with an embossment (13) at the deepest area of said mould. The dimensions and angles of the inner area of said mould are such to obtain the pressed body of the present invention with its dimensions and angles as described above. Preferably, the upper punch (11) represents the heading tool having a concavely shaped inner surface (12) with a protrusion / embossment (13) at its deepest point / area. The lower punch (15) representing the forming mould preferably has an inner surface (16), which is flat. Using such a heading tool (11) during the pressing process has the effect that the detergent composition, initially evenly divided in the forming mould (10), comes in contact with the heading tool (11) at first at the edges of the heading tool (11) and - due to the free-flowing character of the detergent - it is pushed in direction of the recess (14) of the heading tool, except the area of the protrusion / embossment (13). The embossment (13) at the deepest area of the concavely shaped inner surface (12) of the heading tool (11) has the shape and dimension as defined for the cavity (5) above (see Figure 5). The preparation method is not limiting the invention as long as a tablet is obtained having the properties as described above and claimed. The method to form a pressed body of a detergent composition is preferably conducted in a rotary tablet press.

[0044] The particulate detergent composition can be filled uniformly having one phase of uniformly divided detergent ingredient or can be filled with differing (parts of) detergent compositions representing more than one phase, e.g. two, three, four or more than four phases in a pressing mould. Each phase represents compositions comprising (at least one) detergent ingredient(s), however in combinations differing from each other.

[0045] The full pressure power of the heading tool (11) is only applied when the whole space between the heading tool and the forming mould (10) is filled with the detergent powder / granulate. Therefore, the area under the protrusion / embossment (13) is not or only slightly more densified by application of the pressure power than the remainder of the pressed body. The pressing according to the present invention preferably is conducted at a press power in the range of from 15 to 200 kN on the total tablet upper surface (12), more preferably from 30 to 150 kN, even more preferably 45 to 135 kN, most preferably from 60 to 120 kN.

[0046] According to the present invention the pressing mould comprising an upper (11) and a lower (15) punch may be coated to provide non-sticky surfaces. The coatings providing a non-sticky surface are well known in the art.

[0047] The method of the present invention may further comprise the step of filling the cavity (5) of the pressed body with (i) a further pressed body, shaped to fit into the cavity (5), (ii) a hot melt material, (iii) a gel, (iv) a packaged liquid or powder, (v) a sintered material or any combination of (i) to (v).

[0048] Furthermore, the present invention further relates to the use of a tablet according to the present invention for automatic dishwashing, for laundry washing or for cleaning hard surfaces.

Figures:

[0049] The figures show different particularly preferred embodiments of the present invention and should not be considered as restricting the invention.

Figure 1 shows an oval tablet with a convexly curved upper surface (2) along the side surfaces (3, 3') with rounded/ sloped edges. (A) halfside view, (B) top view, (C) view from side surface (3 or 3'), (D) view from front or rear side (4 or 4').

Figure 2 shows a rectangular tablet with a convexly curved upper surface (2) along the side surfaces (3, 3') and along the front (4) and rear (4') side. (A) view from front or rear side (4, 4'), (B) view from side surface (3 or 3'), (C) topview.

Figure 3 shows different appearances of convexly curved tablets: (A) oval tablet with a convexly curved upper surface (2) along the side surfaces (3, 3'); (B) oval tablet with a convexly curved upper surface (2) along the side surfaces (3, 3'), (C) oval tablet with a convexly curved upper surface (2) along the side surfaces (3, 3') and along the front (4) and rear (4') side.

Figure 4 shows an oval tablet with a convexly curved upper surface (2) along the side surfaces (3, 3'). (A) topview, (B) view from side surface (3 or 3'), (C) view from front or rear side (4, 4').

Figure 5 shows a pressing mould and an upper punch (11) having an inner surface (12) which is concavely shaped with a protrusion (13) for preparation of the cavity according to the invention.

Claims

1. A tablet of a detergent composition comprising a pressed body having

(a) an underside having a lower surface (1) and

(b) an upper side having an upper surface (2),

(c) a lateral surface connecting the underside with the upper side, comprising

(i) side surfaces (3, 3'), and

(ii) a front side (4) and a rear side (4'),

wherein the lower surface (1) is flat; and
wherein the upper surface (2) is convexly curved along the side surfaces (3, 3') and/or convexly curved along the front/rear side (4, 4'); and

(d) a cavity (5) in the upper surface (2) in the thickest part (6) of the pressed body.

2. The tablet of claim 1, wherein

(i) the upper surface (2) is convexly curved along the side surfaces (3, 3') and flat and plane-parallel to the lower surface (1) along the front side as well as the rear side (4, 4') or the upper surface (2) is flat and plane-parallel to the lower surface (1) along the side surfaces (3, 3') and convexly curved along the front side as well as the rear side (4, 4') and/or

(ii) the edge of the upper surface (2) to the side surfaces (3, 3') is convexly curved along the side surfaces (3, 3') and the edges of the upper surface (2) to the front side (4) and rear side (4') are concavely curved along the front side (4) and rear side (4') or the edge of the upper surface (2) to the front side (4) and rear side (4') is convexly curved along the front side (4) and rear side (4') and the edge of the upper surface (2) to the side surfaces (3, 3') is concavely curved along the side surfaces (3, 3').

3. The tablet of any of the preceding claims, wherein the convex curvature (7) of the upper surface (2) is flattened in the thickest part (6) of the pressed body forming a plateau (8) plane-parallel to the lower surface (1), and
wherein the upper surface (2) comprises the cavity (5) in at least a part of the plane-parallel plateau (8), preferably in a central part of the plane-parallel plateau (8).

4. The tablet of claim 3, wherein the plateau (8) spans 10 to 40 percent of the upper surface (2), preferably 15 to 35 percent, more preferably 20 to 30 percent.

5. The tablet of any of the preceding claims, wherein at least the edges connecting the upper side with the lateral surfaces are rounded or sloped.

6. The tablet of any of the preceding claims, wherein the cavity (5) is round, oval, elliptic, rectangular, square or polygonal and/or wherein the cavity spans 10 to 40 percent of the surface of the upper surface (2) of the pressed body and/or wherein the cavity spans 3 to 60 percent of the depth of the thickest part (6) of the pressed body.

7. The tablet of any of the preceding claims, wherein the height difference of the pressed body between the thickest part (6) and the edge of the front side (4) and rear side (4') or between the thickest part (6) and the side surfaces (3, 3') is 1.5 to 15 mm.

8. The tablet of any of the preceding claims, wherein the detergent composition of the pressed body comprises an automatic dishwashing composition, a laundry detergent composition, a bleaching composition, a water softening composition or a stain removal composition, preferably an automatic dishwashing composition.

9. The tablet of any of the preceding claims, wherein the pressed body is rectangular, square, round, elliptic, oval, a polygon with more than 4 side surfaces, or any shape between rectangular and elliptic.

10. The tablet of any of the preceding claims, wherein the cavity (5) is filled with further ingredients of a detergent composition, preferably a composition differing in at least one ingredient from the composition of the pressed body.

11. A process for preparing a tablet according to any of claims 1 to 10 by

(i) filling a particulate detergent composition into a pressing mould having at least one concave surface with an embossment having a shape and dimensions as defined for the cavity (5) in claims 1 to 10,

(ii) pressing said detergent composition to prepare a pressed body and

(iii) filling or placing a further composition into the cavity of said pressed body.

12. The process of claim 11, wherein the pressing is carried out in a rotary tablet press.

13. The process of claims 11 or 12, wherein pressing is carried out at a press power in the range of from 15 to 200 kN on the total tablet upper surface, preferably from 30 to 150 kN, more preferably 45 to 135 kN, most preferably from 60 to 120 kN.

14. The process of any of claims 11 to 13, comprising filling the cavity with (i) a further pressed body, shaped to fit into the cavity, (ii) a hot melt material, (iii) a gel, (iv) a packaged liquid or powder, (v) a sintered material, or any combination of (i) to (v).

15. Use of a tablet according to any of claims 1 to 14 for automatic dishwashing, for laundry washing, for cleaning hard surfaces, for bleaching or for water softening.

Drawing