WO2014024170A1

WO2014024170A1 - Tablet coating

Info

Publication number: WO2014024170A1
Application number: PCT/IB2013/056526
Authority: WO
Inventors: Dirk Develter; Gerd Jozef SCHOETERS
Original assignee: Ecover Coordination Center NV
Current assignee: Ecover Coordination Center NV
Priority date: 2012-08-09
Filing date: 2013-08-09
Publication date: 2014-02-13
Anticipated expiration: 2015-02-09
Also published as: BE1020860A3

Description

TABLET COATING

TECHNICAL FIELD

The invention relates to a coated detergent tablet and a method to provide a detergent tablet with a coating. The invention further relates to the use of sugar or sugar alcohol as a coating material for a detergent tablet. The present Invention Is Important In a wide range of household-, institutional- and industrial cleaning applications, washing, dishwashing, and cleaning of hard surfaces. It is especially related to the field of mechanical cleaning, in particular automatic dishwashing.

BACKGROUND Washing of articles with a commercially available dishwasher comprises the use of three kinds of products. Salt Is added to the salt-compartment to make the water softer, a dishwasher formulation is used to clean the articles and a rinse aid Is used to ensure that the articles are rinsed without striping or staining. Users find it difficult to use dishwasher powder because In doing so, the powder is easily spilled on the floor or on the cover of the dispenser compartment, making It even harder to shut. Also the dispensing itself Is an unclear and cumbersome experience. In order to offer a solution to this, the use of tablets with a standard dose has been introduced.

During their successive manipulations, such as Internal transport, packaging and transport through the distribution chains, tablets are often subjected to frictions, by which small fragments may come off. This phenomenon is referred to as friability or the sensitivity of tablets to friction. On the one hand this may lead to annoying dust formation during the production, and on the other hand to loss of product In the box, to dust on the hands of the consumer and to less aesthetic tablets. To reduce this clearly undesirable Impact, tablets are often packed Individually. However, users find It difficult to remove the packaging, they try to avoid direct skin contact with the tablet as well as the product residue on the skin, and they are not satisfied with the resulting waste.

In order to overcome this, tablets have been developed that are coated with a water-soluble film. Users find this confusing, as It Is unclear whether or not the film should be removed before use. A widely used material to provide a tablet with a water-soluble film Is polyvinyl alcohol, However, this type of film is not easily printable. Therefore regulations cannot be met concerning labelling of dangerous substances, which requires that each individual type of package be provided with safety information.

In addition, the biodegradability of the polyvinyl alcohol depends strongly on the degree of polymerization, the used plastic additives as well as of the environment in which the polyvinyl alcohol Is present. An additional challenge is to protect the Ingredients of a tablet from moisture. Detergent tablets are formulated to release the active Ingredients, such as enzymes, during contact with water, Early exposure to for example air humidity may decrease the efficacy of the tablet. Also, the physical characteristics of the tablet can be adversely affected by moisture absorption, for example with disintegration into powder as a result.

Also regarding this aspect, polyvinyl alcohol Is no perfect solution and It remains advisable to protect polyvinyl alcohol packaged tablets from humidity by means of an additional plastic overwrap.

There Is therefore a need for additional Improvements. The present invention aims to provide a solution to one or more of the problems outlined above.

The object of the present Invention Is to provide an alternative packaging material for detergent tablets that generates less waste, which is comfortable and safe in use, on which Information can be applied. It has to provide adequate protection against moisture.

SUMMARY

The present Invention relates to a moulded product In the form of a tablet, provided with protection against moisture absorption in the form of a coating. In particular, the present invention relates to a coated detergent tablet according to claim 1.

A coated detergent according to the present invention has the advantage that It provides protection to the moisture-sensitive contents. In addition, It does not need to be removed before use. The result of this Is an improved user-comfort and confidence. The use of food grade materials has the advantage that a favourable ecological and toxicologlcal profile of the products is obtained.

In addition, the present Invention provides a method for the manufacture of a coated detergent tablet according to an embodiment of the invention, according to claim 11.

The advantage of this method is that the coating can be applied without having to solve In water any formulation for the application of the coating, This has the advantage that during the application little water Is used and brought into contact with the tablet. This is especially beneficial in combination with moisture-sensitive detergent compositions. Furthermore, the invention provides in a number of options for use, according to claim 18. Preferred embodiments are described in sub-claims.

BRIEF SUMMARY OF THE FIGURES

Fig. 1 shows a moulded product In accordance with an embodiment of the Invention,

DETAILED DESCRIPTION

The present invention relates to a moulded product in the form of a tablet that Is provided with protection against moisture absorption. In particular, the present Invention relates to a coated detergent tablet. With the term "detergent tablet " In this invention is meant a tablet-shaped washing or cleaning agent.

The components of a coated detergent tablet are a tablet core, comprising a moisture-sensitive washing or cleaning detergent composition, and a film coating, which surrounds the tablet core.

By the term "moisture-sensitive detergent composition " In this invention is meant: a formulation with cleaning power comprising a moisture sensitive Ingredient, For the provision of the detergent effect, the composition comprises a surfactant or detergent. Examples of moisture-sensitive Ingredients are enzymes, bleaching agents, and tablet-dlsfntegrants. Contact with moisture must be avoided as much as possible prior to the deployment of the tablet, since it reduces the efficacy of the moisture-sensitive components and may also affect the properties of the tablet Itself drastically and detrimentally. Coating composition

The composition for the film coating comprises a sugar or sugar derivative. More specifically, It Is selected from the list of sorbitol, mannltol, maltltol, xylitol, lactitol, isomalt, erytrhitol, lactose, sophorolactone or mixtures thereof.

The advantage of the use of these substances Is their melting point above 40°C. Preferably, the selected sugar or sugar derivative has a melting temperature higher than 40°C, more preferably higher than 50°C, even more preferably 60°C, most preferably higher than 65°C; and lower than 170°C. This choice of material has the advantage that the coating will not melt on contact with a consumer with a body temperature of 37°C - 40°C. Preferably, the selected sugar or sugar derivative Is highly water-soluble, after melting moderately viscous and moreover it solidifies the sugar or sugar derivative quickly, In fact within a minute, and this with a view to Industrial production. With an output of hundreds of tablets per minute, the drying- or congealing time is namely an important factor (n the commercial applicability of this invention.

The film coating Is biodegradable and mostly of food grade quality. It protects the tablet core from moisture and facilitates manipulation of the tablet. In addition to a sugar or sugar derivative, the composition of the coatfng may contain additional Ingredients. These can further optimize the processability and/or properties of the obtained coating. Preferably, the coating comprises a surfactant having a melting point of between 37°C and 90°C, selected from the list of sorbitan palmltate, sorbltan stearate, sorbitan tristearate, ethoxylated (20 EO) sorbitan monostearate, sucrose palmitate, sucrose stearate, sucrose behenate, C16-C18 alkyl polyglucoside, C16- C18 alkylpolyxyloslde, sodium lauroyl lactylate, sodium stearoyl lactylate (SSL), cetyl palmitate, myrlstyl myrlstate, glycerol mono-or dicaprate, glycerol mono-, dh or trilaurate, glycerol mono-, di- or tr!palm!tate, glycerol mono-, di- or tri 12- hydroxystearate, glycerol mono-, di- or tristearate, glycerol mono-, di-, or tribehenate, polygtycerol monostearate, polyglycerol polyricinoleate, food grade polyglycerol esters of fatty acids, dlacetyl tartaric acid ester of mono- and dlglycerldes, fatty alcohol alkoxylates, acetylated monoglycerldes, gecitrylated monoglycerldes, lactylated monoglycerldes, ethylene glycol distearate, ethylene glycol monostearate, pentaerythritol mono-, dl-, trJ- or tetra-stearate esters, pentaerythrltol tetrabehenate, propyleneglycol monostearate, tetradecanol, hexadecanol, octadecanol, polyethylene glycol (PEG) with molecular weight of 400 to 6000, PEG 400 monostearate, PEG 600 distearate, PEG 1500 monostearate, stearyi stearate, adipic acid, azelaic acid, glutaric acid, lecithin, or a mixture thereof. This Ingredient influences the flow properties of the melt, resulting In a reduction of the stickiness and an Improved homogeneity and smoothness. Even more preferably, the above-mentioned surfactant Is water-soluble or dlsperslble In water. Most preferably, the surfactant Is sodium stearoyl lactylate.

In a preferred form of the invention, the composition of the film coating is substantially free of water or organic solvent. Substantially free here means that up to 10%, preferably up to 5%, more preferably up to 3%, most preferably up to 1% of solvent is present in the composition . The use of this dry composition has the advantage that the risk of transfer of moisture Is reduced. As a result, hydrolysis-sensitive Ingredients can be used in the detergent tablet, such as for example sophorolactone in combination with alkaline materials, such as soda or silicate. In a preferred embodiment, the coating formulation has the following composition : 1% sodium stearoyl lactylate, 1-10% of water, remaining isomalt.

In another preferred embodiment, the film coating formulation has the following composition: 1% sodium stearoyl lactylate, 1-10% of water, remaining erythrlol. Preferably, the coating comprises a cellulose or starch derivative, selected from hydroxypropylmethyl cellulose, methylcellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, modified starch, soluble starch, hydrolyzed starch, or a mixture thereof. The presence of such a cellulose or starch derivative promotes disintegration of the coating. These Ingredients have the advantage that they are biodegradable.

Additionally, anti-adhesives such as talc or pigments such as chlorophyll or a combination thereof can be added.

Tablet core

Preferably, in the tablet a surfactant is present. This can be a non-ionic, anionic, cationlc, ampholyte or zwltterlonic surfactant, or mixtures thereof.

In tablets for use in automatic machines, such as preferably dishwasher tablets, the surfactant Is preferably low foaming. In case of excessive foaming, the cleaning function can be reduced as a result of a lowered flow rate of water circulation, which in turn is the result of pressure drop in the conduits or a!r in the circulation pump.

In a preferred embodiment, the surfactant Is a low foaming non-Ionic surfactant that is selected for its humidifying ability and Is preferably selected from ethoxy groups and/or propoxy groups containing non-ionic surfactant agents, and more preferably selected from non-Ionic ethoxy-propoxy fatty alcohols as surfactants. Preferably, the tablet core and/or film coating comprises sophorolactone. Sophorolactone, or sophorolipide in lactone form, Is a low foaming surfactant. Sophorolactone is produced by way of fermentation using microorganisms. It is a bio-renewable detergent. Other surfactants such as anionic surfactants can be used but may require the additional presence of an antlfoamlng agent to suppress foaming.

A tablet according to the Invention may further contain a builder. The builder can be phosphate-based or non-phosphate-based- For ecological reasons, the builder Is preferably non-phosphate-based. The builder or builders may be present at a level from 50 to 90 weight percent and preferably 55 to 80 weight percent. Examples of non-phosphate-based builders Include water-soluble alkali metal- carbonates and -hydrogen carbonates, -borates, -silicates. Specific examples include sodium carbonate, potassium carbonate, sodium- and potassium hydrogen carbonate, silicates including layered silicates and zeolites. Preferably, the tablet core comprises an alkaline detergent composition having at least 10 weight percent of an alkalinity source selected from an alkali metal hydroxide, an alkali metal carbonate, an alkali metal silicate or mixtures thereof. Organic builders may also be present. Examples of organic builders are alkali metal citrates, -succinates, -malonates, -fatty acid sulfonates, -fatty acid carboxylates, -nltrllotrlacetates, -oxydisuccinates, -alkyl and -alkenyldisuccinaten, -oxydiacetaten, -carboxymethyloxysucclnates, -ethylenediamine-tetra-acetates, - tartrate-mono-succinates, -tartate-disucclnates, -tartrate-monoacetates, -tartrate- dlacetates, oxidized starch, oxidized heteropolymeric polysaccharides, polyhydroxy sulfonates, polycarboxylates such as polyacrylates, polymaleates, polyacetates, polyhydroxyacrylates, polyacrylate/polymaleate- and polyacrylaten/ polymethacrylate copolymers, acrylate/maleate/vlnyialcohol-terpolymers, aminopolycarboxylates and polyacetalcarboxylates, as well as polyaspartates and mixtures thereof. Said poiycarboxylates, and polyaspartates have a molecular weight between 500 and 20,000. Alkalimetal citrates, oxydisucci nates, acrylate/maleate copolymers and acrylate/maleate/vinyl-alcohol-terpolymers are particularly preferred non-phosphate based organic builders.

The composition optionally comprises alkali metal silicates. The alkali metal may provide a pH-regulatlng capacity in corrosion protection of metals and against deterioration of tableware, Including benefits for porcelain and glass.

In compositions according to the Invention enzymes may be present. Examples of enzymes suitable for use in cleaning compositions according to the present invention Include lipases, peptidases, amylases, amylolytlc enzymes and other enzymes that degrade, modify or ease the degradation or modification of biochemical contaminants and stains that are found In cleaning situations, so that the contaminants and stains are more easily removed from the object being washed and the contaminants and spots can be removed better at a next cleaning step. By both degradation and modification the removal of contamination can be improved. The enzymes most commonly used in dishwasher compositions are amylolytlc enzymes.

Optionally bleaching agents can be added to a composition according to the invention. These materials can be added in solid form or In the form of encapsulated materials.

The bleaching material may be a chlorine- or bromine-releasing agent or a peroxygen compound. Bleaching materials based on peroxygen compounds are preferred. Organic peroxy acids or precursor products thereof can be used, as well as Inorganic peroxygen-forming compounds. Examples of the latter are monopersulfate-, perborate monohydrate-, perborate tetrahydrate-, and percarbonate salts. Peroxy acid bleach precursors are well known to one skilled in the art. As non- limiting examples, Ν,Ν,Ν',Ν'-tetra-acetylethylenediamine (TAED), sodium nonanoyloxybenzene sulfonate (SNOBS), sodlunrv benzoyloxy benzene sulfonate (SBOBS), decanoyloxybenzoic acid (DOBA) are mentioned.

In the tablet a crystal growth Inhibitor may be present, For example in a dishwasher detergent. Suitable crystal growth inhibitors are for example carboxymethyl Inulln (CMI), hydroxyethylene-l,l-dlphosphonate (HEDP), aminotris (methylene phosphon acid) (ATMP) and dlethylenetriamine penta (methylene phosphon acid (DTPMP).

Additional optional components include buffering agents, enzyme-stablllzlng agents, such as polyalcohols, e.g. glycerol and borax; optical brlghteners, greying Inhibitors, fragrances and colorants.

In case the detergent tablet concerns a toilet-decalclfylng product, the tablet core consists, in addition to the above ingredients, of one or more mineral or organic acids.

Coated detergent tablet

The detergent tablet according to an embodiment of the Invention is protected by a film coating against the absorption of moisture. This is only very limited, so that the tablet does not swell by absorption of water from the air, for example. This allows for good storage stability.

The protection of the coated detergent tablet Is such that it only has a weight gain of up to 7% with respect to the weight of the coated detergent tablet at the start of the test, when exposed for 8 weeks at an environmental temperature of 25°C and a relative air humidity of 70%.

In a preferred embodiment, the tablet Is a dishwasher tablet, textile-washing tablet, washing-up tablet, toilet-decalcifying tablet or all-purpose cleaner cleaning tablet.

Because a standard, non-coated tablet has already been optimized in properties such as release profile, strength, composition, it is important that these are at least maintained or improved. Preferably, a tablet is in its physical characteristics equivalent to or better as compared to a standard, non-coated tablet, Preferably a tablet according to an embodiment of the invention shows an improvement of the friability with at least 2% with respect to the tablet without coating. The presence of the coating reduces the weight loss due to friction compared to a standard tablet without a coating- The friability, or the sensitivity of tablets for friction, is tested In a frlabilator as follows: 3 tablets are placed together In a plastic round container (diameter 92 mm, height 11.5 mm) and rotated along the transverse axis at 70 revolutions per minute. After 25 minutes, the total weight loss is determined, wherein the friability is expressed as the percentage weight loss of the tablets after the test with respect to the initial weight and wherein the friability must be as low as possible.

Typical values for the tablets currently available i.e. a tablet without coating, are 2-3%. For the coated tablets according to an embodiment of the Invention, this is typically equal to or less than 1%. The film coating improves the friability of the tablets. Typically it is observed that the friability of coated tablets according to an embodiment of the Invention is at least 2% lowered with respect to the tablet without coating. This has the advantage that a packaging of the tablet In a plastic bag or polyvinyl alcohol film, as has so far been customary, can be omitted. Preferably a tablet according to an embodiment of the Invention provides a dissolution time that Is Increased with no more than 200 seconds with respect to the tablet without the coating.

The dissolution time can be determined as follows on the basis of a Varian 705 DS

"Dissolution apparatus ": a 1L cup is filled with 900 ml medium hard water of 16°dH and a temperature of 30°C. Herein a basket of metal wire with a mesh width of 10 mm x 10 mm is suspended, containing one tablet. The basket Is stirred in the cup at 250 r/min.

The dissolution time of a tablet in the state of the art is 800-900 seconds. Coated tablets according to an embodiment of the invention have a dissolution time oF 800-1200 seconds. This features tablets with a good solubility and/or disintegration. Preferably, a tablet according to an embodiment of the invention has a compression strength that Is reduced with no more than 10 kg relative to the tablet without the coating.

The compression strength of a tablet can be determined with a CT6 device of Engineering Systems (NOTTM) Ltd., using two round, flat 25 mm plates. The compression strength of a tablet in the state of the art, as determined by the above method, is typically 120-140 kg. Coated tablets according to an embodiment of the invention have a compression strength of at least 110 kg. In a preferred embodiment of a tablet according to the invention, the coating is provided with an Information carrier, such as a text, symbol or logo. An Individual tablet can be advantageously provided with information. Preferably, the information carrier is applied with plant-based Ink, such as linseed oil or soybean oil. These are standard re-growable and therefore sustainable raw materials.

In a preferred embodiment of a tablet according to the invention, the tablet has a weight of 2 to 40 grams, preferably of 10 to 30 grams, most preferably of 18 to 20 grams.

Method

In a second aspect, the Invention provides a method for the fabrication of a coated detergent tablet according to an embodiment of the invention .

In a method according to an embodiment of the Invention, a detergent tablet Is provided with a coating by means of dip coating.

For this purpose, a f!lm-coatlng composition comprising a sugar derivative selected from sorbitol, mannitol, maltito), xylltol, lactltol, isomalt, erytrhltol, sophorolactone or mixtures thereof are melted. Then a tablet core comprising a moisture-sensitive detergent composition is dipped into the melt in order to surround the detergent tablet core with melt.

The melt-coated detergent tablet core is removed from the melt at such a rate as to provide, after drying of the melt on said tablet, a film coated tablet with a film thickness suitable to protect against a weight gain of more than 7% when exposed to a relative air humidity of 70% for 8 weeks at 25°C; preferably with a film thickness of 0,05-0.5 mm, Drying of the melt on the above-mentioned tablet provides a coated detergent tablet. Alternatively, the melt is poured over the tablet and the tablet itself Is taken out of the melt by means of a conveyor belt, for example In the case of industrial production.

Preferably, an Information carrier is applied by pressing an information carrier into the coating. In another preferred embodiment, a method for the fabrication of a coated detergent tablet, according to a preferred form of the invention, comprises the steps of:

-melting of a film coating composition comprising a sugar derivative selected from sorbitol, mannltol, maltltol, xylitol, lactitol, Isomalt, erytrhitol, sophorolactone or mixtures thereof,

-spraying of the melt on a tablet core comprising a moisture-sensitive detergent composition, In order to surround the detergent tablet core with melt and to provide a film-coated tablet with a film thickness suitable to protect against a weight gain of more than 7% when exposed to a relative air humidity of 70% for 8 weeks at 25°C; preferably with a film thickness of 0.05-0.5 mm,

-drying of the melt on the above-mentioned tablet in order to obtain a coated detergent tablet, Preferably, the tablet Is powdered with a non-molten sugar derivative or a glucose polymer and the powdered material Is melted, preferably by Infrared. Preferably, the film-coating composition is substantially free of water or organic solvent. Preferably, the film-coating composition does not contain more than 10%, more preferably not more than 5%, most preferably less than 3% water. Preferably, the method comprises a step wherein the film-coating material solidifies In less than 15 minutes, preferably In less than 10 minutes, still more preferably in less than 5 minutes and most preferably In less than 60 seconds upon contact with the detergent tablet.

The invention preferably relates to methods for the dish wash in mechanical dishwashing machines wherein the washing liquid has a low pH. With a low pH Is meant that the pH of the washing liquid Is preferably higher than 6,5; more preferably 7.5 or higher, and most preferably 8.5 or higher. Preferably the pH Is lower than 11, more preferably less than 10 and most preferably lower than 9.5.

Most preferably, the pH range is between 8.5 and 10.5.

The invention preferably relates to methods for mechanically washing soiled articles with a washing liquid at a temperature of 55°C or lower. Application

In a third aspect, he Invention provides a number of uses. In a preferred embodiment the invention provides the use of a film-coating composition comprising a sugar derivative selected from sorbitol, mannltol, maltltol, xylitol, lactitol, Isomalt, erytrhltol, lactose, sophoro!actone or mixtures thereof as a coating material for a detergent tablet. The above-mentioned sugar derivatives have the advantage that they are easily melted and require little or no water or any other solvent to be able to be applied on a detergent tablet. Preferably, the film-coating composition Is used as a coating material for a dishwashing tablet, laundry tablet, dish wash tablet, toilet decalcifying tablet or all-purpose cleaning tablet. This has the advantage that the packaging of the tablet is not to be removed before use, This avoids waste. Preferably, the film-coating composition comprises 85%-99% isomalt, sorbitol or erythrltol, 0.1%-5% sodium stearoyl lactylate, and 0.001%-10% water, expressed as a weight percentage relative to the total weight of the composition. Packaging forms

In a preferred embodiment of the process, tablets are linked to each other into a bar, using melt. Preferably, hereby the individual tablets, which will form part of the bar, are first individually coated with melt, after which, by means of hot melt and a mould, coated tablets can be linked to each other into a bar with melt.

This Is Illustrated by means of the following test. Three-layered commercially available Ecover classic tablets were cut In half by way of proof of concept, placed in a metal frame or mould with spacers and topped with melt to obtain a

"Toblerone "-like bar comprising multiple dishwasher tablets.

The obtained result Is shown In Fig. 1. In an industrial production this can be carried out at high speed with tablets of the desired weight, directly after the tabletting on the conveyor belt.

This type of packaging allows consumers the opportunity of dosing a tablet-shaped washing or cleaning agent to their own discretion and need, while maintaining the ease of use and without spillage of loose powder or liquid. Example 1

Rectangular, commercially available three-layered classic dishwashing tablets (36 mm x 26 mm x 14 mm) of the brand Ecover were used either un-treated or treated. The treatment consisted of the application of a film coating composition.

The various compositions that were tested are shown in Table 1.

The tablets were coated according to a dip coating method as follows: a cup with coating mixture Is placed in a hot oil bath. The coating composition Is melted at the respective melting temperature. The tablets are dipped Into the melt In such a way that the tablet is coated with molten material. The tablets are taken out of the melt at a rate that is in accordance with the desired coating thickness. In this test, the tablets were pulled from the melt in one smooth movement, In about 1 second. Subsequently, the coated tablets were hung up to dry until the coating layer solidified. For each coating, 11 tablets were treated with a same coating In order to have plenty of tablets available before and after a stability test, for testing on a number of parameters.

The stability test was organized at an uncontrolled air humidity for 4 weeks at 40°C. Parameters such as friability, dissolution time and strength were measured, according to the test method as described previously.

This example shows that coatings A and B significantly reduce the friability of the tablet and that this reduction continues at prolonged storage.

Table 1 : Coating compositions, expressed in weight percent of the coating composition

Example 2

Tablets were re-coated as in Example 1, but with erythrltol- and isomalt-based coating compositions, These sugar alcohols were - whether or not - combined with surfactants, with ethanol and with other sugar alcohols such as listed below.

Here, four parameters were listed, namely the melting point (wherein "+ " means a relatively low melting point), the viscosity of the melt ( "+ " for a low viscosity), the appearance and the stickiness one hour after the coating ( "1 " = not sticky, "3 " = very sticky) of the coating after solidification.

The erythritol coating solidifies thereby much faster than isomait, I.e. within one minute. Addition of a surfactant, in particular of sodium stearoyi lactylate (SSL), provided a smoother and more homogeneous surface.

Ervthrltol

Melt Visc Appearance

- 100% + visible "crystal-lines "

2% 55 L + + smoother, sometimes sores at coating

- 5% SSL + + SSL droplets in melt

- 10% SSL + SSL spots

- 20% SSL + + SSL spots

- 49% Isomalt G5, 2% sorbitol +/- +/- slow crystallization

10% glutarlc acid + + matte-coated, clear 15% structure

15% lactitol + + rough

- 30% lactitol + +/- "whlte marking " relatively slow crystallization

- 20% lactitol 5% SSL + - slow crystallization

- 30% maltitol +/- slow crystallization

7% water + + rough, crystal structure

- 10% water 1% SSL + + rough, clear crystal

structure

Isomalt

Melt Visc Appearance

- 100% - - slightly sticky

- 20% SSL +/- - SSL-spots

- 10% glutarlc acid +/- - slow curing

10% sorbitan palmltate +/- - SP along exterior

- 5% sorbitol 5% sorbitan +/- - SP along exterior

palmitate

- 2% sorbitol 2% sorbitan +/- - SP along exterior

palmltate

- 1% H20 sticky 2

1% H20 1 % SSL sticky l

1 % H20 2% SSL sticky 1 after cooling

123°C

5% H20 1 % SSL +/-+/- sticky ness minimal

after 2h

1% H20 1 % EtOH H20 sticky 3, hardly after Id Example 3

Two coating compositions were selected on the basis of the Information collected in the above experiments, namely 96% isomalt + 2% sodium stearoyl lactylate + 1% water; and 93% erythrltoi + 2% sodium stearoyl lactylate + 5% water.

Tablets were coated with these coating compositions In accordance with the method described In Example 1 ,

After drying smooth light beige isomalt-coated tablets are obtained and rougher erythrltoi tablets. These tablets are stable, measured at a relative air humidity of 70% for 8 weeks at 25°C,

Claims

1. A coated detergent tablet comprising a tablet core surrounded by a film coating, wherein the tablet core comprises a moisture-sensitive detergent composition ; the film coating comprises a sugar or sugar derivative selected from sorbitol, mannitol, maltitol, xylltol, lactitol, isomalt, erytrhito), lactose, sophorolactone or mixtures thereof; and wherein the film coating protects the tablet core against an Increase in weight, expressed in relation to the tablet, of more than 7% when exposed to a relative air humidity of 70% for 8 weeks at 25°C.

2. Tablet according to claim 1, with a friability not exceeding 1 %.

3. Tablet according to claim 1 or 2, characterized in that the tablet Is a dishwashing tablet, a laundry tablet, a dish wash tablet, a toilet decalcifying tablet or an all-purpose cleaning tablet.

4. Tablet according to any one of the above claims 1-3, characterized in that the tablet core comprises an alkaline detergent composition with at least 10 weight percent of an alkalinity source, selected from an alkali metal hydroxide, an alkali metal carbonate, an alkali metal peroxyhydrate, an alkali metal bicarbonate, an alkali metal silicate or mixtures thereof.

5. Tablet according to any one of the above claims 1-4, characterized In that the tablet core and/or the film coating comprises sophorolactone.

6. Tablet according to any one of the above claims 1-5, characterized In that the film coating comprises a surfactant with a melting point between 37°C and 90°C selected from sorbitan palmitate, sorbitan stearate, sorbitan tristearate, ethoxylated (20 EO) sorbitan monostearate, sucrose palmitate, sucrose stearate, sucrose behenate, C16-C18 alkyl polyglucoside, C16-C18 alkylpolyxyloside, sodium lauroyl lactylate, sodium stearoyl lactylate (SSL), cetyl palmitate, myristyl myristate, glycerol mono- or dicaprate, glycerol mono-, di- or trilaurate, glycerol mono-, dl- or tripalmitate, glycerol mono-, di- or trl 12-hydroxystearate, glycerol mono-, dl- or tristearate, glycerol mono-, di-, or tribehenaat, polyglycerol monostearate, poiyglycerol polyricinoleate, polyglycerol esters of fatty acids of food-grade quality, diacetyl tartaric acid ester of mono- and dlglycerides, fatty alcohol alkoxylate, acetylated monoglycerides, d trylated monoglycerldes, lactylated monoglycerldes, ethylene glycol distearate, ethylene glycol monostearate, pentaerythrltol mono-, dl-, trl- or tetrastearate esters, pentaerythrltol tetrabehenate, propyleneglycol monostearate, tetradecanol, hexadecanol, octadecano!, PEG with MW from 400 to 6000, PEG 400 monostearate, PEG 600 dlstearate, PEG 1500 monostearate, stearyl stearate, adipic acid, azelaic acid, glutarlc acid, lecithin, or a mixture thereof.

Tablet according to any one of the above claims 1-6, characterized in that the coating comprises an additive selected from colorant, talc, hydroxypropyl methylcellulose, methyl cellulose, hydroxypropyl cellulose, hydroxyethyl cellulose, modified starch, soluble starch, hydrolyzed starch, or a mixture thereof.

Tablet according to any one of the above claims 1-7, characterized in that the film coating is provided with an Information carrier such as a text, symbol or logo.

Tablet according to claim 8, characterized in that the information carrier is applied with plant-based ink.

Tablet according to any one of the above claims 1-9, with a weight of 2 to 40 grams.

Method for the fabrication of a coated detergent tablet according to any one of claims 1-10, comprising the steps of:

-melting of a film-coating composition comprising a sugar derivative selected from sorbitol, mannitol, maltitol, xylitol, lactltol, isomalt, erytrhitol, sophorolactone or mixtures thereof;

-dipping of a tablet core comprising a moisture-sensitive detergent composition into the melt, in order to surround the detergent tablet core with melt;

-removal of the melt-coated detergent tablet core from the melt, at such a rate as to provide, after drying of the melt on the above-mentioned tablet, a film coated tablet with a film thickness suitable to protect against a weight gain of more than 7% when exposed to a relative air humidity of 70% for 8 weeks at 25°C;

-drying of the melt on the above-mentioned tablet, in order to obtain a coated detergent tablet.

Method according to claim 11, wherein an information carrier Is pressed into the coating.

Method for the fabrication of a coated detergent tablet according to any one of the claims 1-10, comprising the steps of;

-melting of a film-coating composition comprising a sugar derivative selected from sorbitol, mannitol, maltitol, xylltol, lactltol, isomalt, erytrhitol, sophorolactone or mixtures thereof; -spraying of the melt on a tablet core comprising a moisture-sensitive detergent composition, in order to surround the detergent tablet core with melt and to provide a film coated tablet with a film thickness suitable to protect against a weight gain of more than 7% when exposed to a relative air humidity of 70% for 8 weeks at 25°C;

-drying of the melt on above-mentioned tablet in order to obtain a coated detergent tablet.

14. Method according to any one of claims 10-13, wherein the powdering takes place with a non-molten sugar derivative according to claim 1 and wherein the powdered material is melted by infrared.

15. Method according to any one of claims 10-14, wherein above-mentioned film-coating composition contains a maximum of 10% water or organic solvent,

16. Method according to any one of claims 10-15, wherein the film coating composition is as follows:

85% - 99% Isomalt, sorbitol or erythrito!,

0.1% - 5% sodium stearoyl lactylate and

0.001% - 10% water,

expressed In weight percentage relative to the total weight of the composition .

17. Method according to any one of claims 11 -16, which includes the step of: linking at least two tablets with melt to provide a bar,

18. Use of a sugar derivative selected from sorbitol, mannitol, maltltol, xylitol, lactitol, isomalt, erytrhitol, lactose, sophorolactone or mixtures thereof as coating material for a detergent tablet.

19. Use according to claim 18, wherein the detergent tablet Is a dishwashing tablet, a laundry tablet, a dish wash tablet, a toilet-decalcifying tablet or an all-purpose tablet