EP3383989B1 - Coated detergent tablet - Google Patents

Description

FIELD OF THE INVENTION

The present invention relates to the field of detergent tablets, especially detergent tablets for dishwashers.

STATE OF THE ART

Detergents in tablet form have many advantages over other detergents, in the form of liquid or powder, in particular as regards dosing, storage or transport.

Detergent tablets are most often prepared by premixing various components preferably in the form of powder or granules but also in liquid form. This premix is then compacted using a press to form a tablet. Industrially, rotary presses are preferably used to form compacted tablets at high rates.

The field of detergency imposes particular constraints to form tablets since some components poorly support compression, other components can react with each other before use and thus reduce the effectiveness of the tablet during use, and c This is why multilayer tablets have been developed. In fact, such multilayer tablets make it possible both to separate the components that can react with each other, and to only compress the compression-sensitive components once by inserting them into the last layer. Multilayer tablets may exhibit slightly delayed disintegrations between different layers, the first layer having been compressed several times thus generally has a longer disintegration than subsequent layers less compressed.

One of the recurring problems in the field of detergent tablets is the resistance of these tablets over time, in particular so that they can be handled and transported without them disintegrating or disintegrating.

In this regard, it has been proposed to coat the detergent tablets with a coating or a film, which is also called "coating" according to the Anglo-Saxon term, to strengthen the strength of the tablets. For example, such teachings are found in a patent of the company Colgate Palmolive published in 1966 under the reference US 3,231,505 , where it is proposed to coat the detergent tablet with a film of synthetic organic polymer, for example polyvinyl alcohol (or PVA according to the acronym of polyvinyl alcohol), in order to increase the resistance to abrasion and accidental breakage of the tablet.

Similarly, the international application of PROCTER & GAMBLE published in 2001 under the reference WO 01/64829 relates to the coating of detergent tablets with a water-dispersible coating composed for example of PVA, to enable the production of tablets having a strength and a mechanical strength similar to traditional tablets while being less compacted and therefore capable of being dissolved more quickly.

Another patent, on behalf of Dalli-Werke GmbH and Co. KG, published under reference EP 2 196 531 discloses a coating for detergent tablets, such as dishwasher tablets, for increasing the stability and strength of the tablet, said coating being water-soluble and containing at least one graft copolymer of polyvinyl alcohol and polyethylene glycol.

In the patent US 5,916,866 there is provided a detergent tablet formed from at least one active detergent and a detergency builder, and being coated with a coating formed from a water-soluble organic polymer, such as a copolymer of acrylate and maleate.

The coatings proposed in these documents for coating the detergent tablets are intended to increase the stability of said tablets by forming a layer which mechanically maintains the compacted detergent composition. However they are complex to implement, may denature the action of the detergent tablet or reduce the effectiveness and / or disintegration of the detergent tablet.

An object of the present invention is to provide a detergent tablet, especially for dishwasher application, having improved efficiency, mechanical strength and stability allowing the tablet to be handled and stored without undergoing degradation.

An object of the present invention is also to provide a detergent tablet, especially for dishwashing application, having an improved action while having a manufacturing method simple to implement.

SUMMARY OF THE INVENTION

To this end, there is provided a detergent tablet comprising a body formed from compacted powder, said body being coated with a water-soluble coating, said water-soluble coating having a composition comprising a film-forming agent and water, characterized in that the The composition of the water-soluble coating further comprises at least one specific agent to improve the rinsing efficacy of the detergent tablet.

• le revêtement hydrosoluble a une épaisseur comprise entre 1 µm et 1000 µm, de préférence comprise entre 5 µm et 300 µm, et de préférence encore comprise entre 15 µm et 150 µm.
• le revêtement hydrosoluble a une masse représentant entre 0,5% à 15% en masse par rapport au poids total de la tablette détergente, de préférence entre 2% à 5% en masse par rapport au poids total de la tablette détergente.
• l'agent spécifique permettant d'améliorer l'efficacité de rinçage est un agent anti-spotting et/ou anti-filming.
• l'au moins un agent spécifique est dans une proportion comprise entre 0.05% et 50% en masse par rapport au poids total de la composition du revêtement hydrosoluble, de préférence entre 2% et 20% en masse par rapport au poids total de la composition du revêtement hydrosoluble.
• l'au moins un agent spécifique est un polymère.
• l'au moins un agent spécifique est choisi parmi les copolymères acrylique/styrène modifiés hydrophobes, ou leurs combinaisons.
• l'au moins un agent spécifique est choisi parmi les copolymères d'acide acrylique et de monomère sulfoné, les copolymères d'acide acrylique et d'acide sulfonique, les copolymères d'acide acrylique et d'acide maléique, ou leurs combinaisons.
• l'au moins un agent spécifique est choisi parmi les polymères carboxylate, les polymères carboxylate modifiés hydrophobes, en particulier les polymères HASE, et leurs combinaisons.
• l'agent filmogène est dans une proportion comprise entre 5% et 80% en masse par rapport au poids total de la composition du revêtement hydrosoluble, de préférence comprise entre 20% et 60% en masse par rapport au poids total de la composition du revêtement hydrosoluble, et de préférence encore comprise entre 30% et 55% en masse par rapport au poids total de la composition du revêtement hydrosoluble.
• l'agent filmogène est choisi parmi les alcools polyvinyliques, de préférence parmi les alcools polyvinyliques ayant un taux d'hydrolyse avec un pourcentage molaire supérieur ou égal à 40%, de préférence compris entre 70% et 98%, et de préférence encore compris entre 80% et 90%.
• l'agent filmogène est choisi parmi les alcools polyvinyliques ayant une masse molaire en masse comprise entre 10000 g/mol et 200000 g/mol, et de préférence comprise entre 15000 g/mol et 100000 g/mol.
• la composition du revêtement hydrosoluble comprend en outre un agent humectant.
• l'agent humectant est dans une proportion inférieure ou égale à 25% en masse par rapport au poids total de la composition du revêtement hydrosoluble, de préférence dans une proportion comprise entre 1% et 20% en masse par rapport au poids total de la composition du revêtement hydrosoluble, de préférence encore dans une proportion comprise entre 2% et 10% en masse par rapport au poids total de la composition du revêtement hydrosoluble.
• l'agent humectant est choisi parmi la glycérine, les polyéthylènes glycol, et leurs combinaisons.
• l'agent humectant est choisi parmi les polyéthylènes glycol ayant une masse molaire en masse comprise entre 1000 g/mol et 4000 g/mol.

Preferred but non-limiting aspects of this detergent tablet, taken alone or in combination, are as follows:

• the water-soluble coating has a thickness of between 1 μm and 1000 μm, preferably between 5 μm and 300 μm, and more preferably between 15 μm and 150 μm.
• the water-soluble coating has a mass representing between 0.5% and 15% by weight relative to the total weight of the detergent tablet, preferably between 2% and 5% by weight relative to the total weight of the detergent tablet.
• the specific agent for improving the rinsing efficiency is an anti-spotting and / or anti-filming agent.
• the at least one specific agent is in a proportion of between 0.05% and 50% by weight relative to the total weight of the composition of the water-soluble coating, preferably between 2% and 20% by weight relative to the total weight of the composition water-soluble coating.
• the at least one specific agent is a polymer.
• the at least one specific agent is selected from hydrophobic modified acrylic / styrene copolymers, or combinations thereof.
• the at least one specific agent is selected from copolymers of acrylic acid and sulfonated monomer, copolymers of acrylic acid and sulfonic acid, copolymers of acrylic acid and maleic acid, or combinations thereof.
• the at least one specific agent is chosen from carboxylate polymers, hydrophobic modified carboxylate polymers, in particular HASE polymers, and combinations thereof.
• the film-forming agent is in a proportion of between 5% and 80% by weight relative to the total weight of the composition of the water-soluble coating, preferably between 20% and 60% by weight relative to the total weight of the coating composition water-soluble, and more preferably between 30% and 55% by weight relative to the total weight of the composition of the water-soluble coating.
• the film-forming agent is chosen from polyvinyl alcohols, preferably from polyvinyl alcohols having a degree of hydrolysis with a molar percentage greater than or equal to 40%, preferably of between 70% and 98%, and more preferably between 80% and 90%.
• the film-forming agent is chosen from polyvinyl alcohols having a molar mass of between 10,000 g / mol and 200,000 g / mol, and preferably of between 15,000 g / mol and 100,000 g / mol.
• the composition of the water-soluble coating further comprises a humectant.
• the humectant is in a proportion less than or equal to 25% by weight relative to the total weight of the composition of the water-soluble coating, preferably in a proportion of between 1% and 20% by weight relative to the total weight of the composition water-soluble coating, preferably in a proportion of between 2% and 10% by weight relative to the total weight of the composition of the water-soluble coating.
• the humectant is selected from glycerine, polyethylene glycol, and combinations thereof.
• the humectant is chosen from polyethylene glycols having a molar mass of between 1000 g / mol and 4000 g / mol.

DETAILED DESCRIPTION OF THE INVENTION

A detergent product is therefore proposed in the form of a coated tablet, also called a coating, formed of a water-soluble solution, making it possible to cover the surface of the tablet by forming a homogeneous film adhering to the surface of the tablet. The detergent product in tablet form may for example be a dishwashing detergent.

The detergent tablet proposed comprises a body formed for example from compacted powder, said body being coated with a water-soluble coating. The water-soluble coating used has a composition comprising a film-forming agent and water, and has the particularity of further comprising at least one specific agent to improve the rinsing efficiency of the detergent tablet. As will be seen below, the composition of the water-soluble coating may also comprise a humectant.

The specific agent used to improve the rinsing efficacy of the detergent tablet is preferably selected from compounds having an "anti-spotting" action (which could also be described as anti-trace action) and / or action "anti-filming" (which could also be called anti-film action).

By "spotting" is meant any trace on a dishware element, caused by the drying of drops of water on the surface of the material forming the dishware, in particular glass. Calcium and magnesium present in water can for example be deposited on the surface of the glass and form traces during drying in the dishwasher. The higher the water hardness, the higher the amount of calcium and magnesium ions it contains.

"Filming" means any appearance of a film / white deposit on all or a large part of the surface of the material forming the dishware, in particular the opacification of the glass. The calcium and magnesium ions present in the water can for example form deposits of limestone more or less uniform on the surface of the glass.

As will be seen later in this description, the use of a specific agent intended to improve the rinsing efficiency of the detergent tablet, such as an anti-spotting and / or anti-filming agent, in the composition forming the coating coating the detergent tablet, allows for increased stability over existing coated tablets.

Providing such a specific agent in the composition forming the coating coating the detergent tablet is also particularly advantageous since it makes it possible to use in particular agents generally being in liquid form and which are therefore difficult to use in tablet detergent formulations. Indeed, specific agents in liquid form are generally difficult to introduce into the powder mixture to be compacted, and further cause problems of stability of the final compacted tablet, especially because of the water present in such agents specific in liquid form that can react with other raw materials of the detergent formula.

Detergent product in tablet form

The detergent product used is preferably in the form of a tablet which has sufficient cohesion to be handled without being broken and which easily disintegrates in water.

The tablet does not require a high hardness, its cohesion and mechanical strength being enhanced by the use of a coating coming to coat the tablet, that is to say adhere to the surface of the tablet.

The tablet has a body formed by compaction for example, in particular from a mixture of raw materials in the form of powder or granules, but also in liquid form.

The detergent tablets consist of a mixture of components comprising different actions, these components may for example be chosen from surfactants, fillers, sequestering agents, bleaching agents, enzymes, bleaching activators, alkaline agents, polymers, perfumes, dyes.

The detergent tablet may consist of a single layer or a stack of several layers that are superimposed on each other, forming a uniform and compact block. For a multilayer tablet, the different layers may have the same or different composition.

The tablet preferably has an elongated shape with a section having any shape, for example circular, oval, octagonal, or parallelepipedal.

When the section of the tablet is parallelepiped, typically square or rectangular, the corners of the tablet can be curved so that they are less brittle.

Each layer preferably has the same section so that the stack of layers forms a uniform tablet.

The detergent tablet preferably has a mass of between 1 gram and 100 grams, and more preferably between 5 grams and 60 grams.

The tablet preferably has a mechanical strength of between 5 Newtons and 300 Newtons, and more preferably between 10 Newtons and 90 Newtons.

To form a multilayer tablet, the manufacturing process used generally consists of progressively forming a complex of several layers and compacting this complex with each new addition of layer so as to solidify the tablet. The tablets are manufactured by direct compression with a hydraulic press or a rotary press, especially when it is desired to form tablets at an industrial rate.

The first step is therefore to mix the components intended to form the compositions corresponding to each of the layers. The mixture corresponding to the first layer is introduced into the matrix and then pre-compacted to form the first layer. The mixture of the second layer is then introduced into the matrix on the first layer and then pre-compacted as for the first layer, in the same way the other layers of the tablet are introduced into the matrix. The set of layers is then compacted to obtain a shock-resistant tablet.

The pre-compaction forces used are preferably between 0 kN and 100 kN (kilonewtons), and more preferably between 0 kN and 50 kN. The compression force used for the final compaction is preferably between 5 kN and 200 kN, and more preferably between 10 kN and 100 kN.

A dishwasher detergent tablet includes a combination of one or more of the components described in more detail below, without being limiting thereto.

enzymes

To allow the degradation of the soil on the dishes, the tablet preferably contains enzymes to form an enzymatic system. These enzymes are for example chosen from proteases, amylases, lipases, and combinations thereof.

These enzymes are generally in the form of granules that contain a certain amount of active enzymes.

The detergent tablets that are preferably used have an overall composition integrating enzymes whose total amount of active enzymes is between 0.003% and 5% by weight, and preferably between 0.003% and 2% by weight.

Amylases can be used to decompose starch-based stains, such as, for example, the product dispensed by Genencor under the reference "Powerase 16000HS".

The tablet may also contain proteases to act on protein tasks such as meat and eggs. One can for example use the product referenced "Excellase 2250D" distributed by the company Genencor.

The tablet may also contain lipases to improve the breakdown of grease stains on the dishes.

Bleaching agent and bleach activators

To allow the degradation of oxidizable stains such as tea, coffee, red wine, the tablet preferably contains a bleaching agent, that is to say a substance capable of directly or indirectly oxidizing the organic compounds described.

The bleaching agents may be of the sodium perborate mono or tetrahydrate type, sodium percarbonate, sodium persilicate, and sodium persulfate.

In alkaline medium, these compounds release hydrogen peroxide in contact with water, thus generating a source of active oxygen.

The tablet preferably comprises between 1% and 50% by weight of bleaching agent, and more preferably between 5% and 20% by weight.

To provide even more effective dish washing, the tablet preferably contains a tetraacetylenediamine (TAED), pentaacetylglucose (PAG), tetraacethylglycoluryl (TAGU) and sodium benzoloxybenzene sulfonate bleach activator.

These activators react in the wash bath with hydrogen peroxide, giving chemical compounds whose performance on organic soils is higher, especially for reasons of chemical affinity.

The tablet preferably comprises between 0.5% and 40% by weight activator of the bleaching agent, and more preferably between 1% and 10% by weight.

Preferably, the tablet comprises a ratio between bleaching agents and bleach activators corresponding to a molar ratio of 6 to 1, more preferably a molar ratio of 5 to 1.

The tablet may also contain catalysts to improve the effectiveness of agents on oxidizable stains. Mention may be made, for example, of manganese catalysts such as the product referred to as "Peractive FDO X" marketed by Weylchem.

Detergents / sequestrants (or builders)

The effectiveness of the washing will be increased if the tablet further comprises detergency builders, also called "builders".

Detergent additives trap metal ions such as calcium and magnesium present in the wash solution by complexation, ion exchange or precipitation.

Detergent adjuvants are preferably present in an amount of from 5% to 99% by weight, and more preferably from 10% to 50% by weight.

Non-phosphorus water soluble builders can be organic or inorganic.

The inorganic compounds that may be present are chosen from zeolites, phyllosilicates, alkali metal carbonates (generally sodium), and sodium silicates, mixtures of sodium carbonate and sodium silicates, such as the product referenced "questlock Distributed by the company Amcol.

The organic compounds that may be present are chosen from polycarboxylate polymers such as polyacrylates, acrylic / maleic copolymers and acrylic phosphonates, monomeric polycarboxylates such as citrates, gluconates, oxydisuccinates, mono-, di- and glycerol tri-succinates, carboxymethyloxysuccinates, polycarboxylic amino compounds such as methylglycinediacetate (MGDA) carboxymethyloxymalonates, glutamic diacetic acid (GLDA), imminodisuccinate (IDS), ethylenediamine disuccinate (EDDS), dipicolinates, nitrilotriacetates and hydroxyethyliminodi acetates.

Sodium citrate and methylglycinediacetate acid (MGDA) are particularly preferred detergency builders for dishwasher tablets.

The class of water-soluble phosphorus adjuvants includes orthophosphates, methaphosphates, pyrophosphates and alkali metal polyphosphates.

Specific examples of inorganic phosphorus detergency builders include sodium and potassium tripolyphosphates, orthophosphates and hexametaphosphates.

Sodium tripolyphosphate is a particularly preferred phosphorus adjuvant for dishwasher tablets. It exists in hydrated, anhydrous or partially hydrated form, and mixtures of these forms can be used to regulate the rate of disintegration and dissolution of the tablet.

To allow efficient washing of the dishes, the pH of the wash solution must be at least 9 and preferably between 9.5 and 12.5. Most detergency builders are alkaline, so there is no need to add other compounds to the tablet to adjust the pH.

surfactants

For efficient washing, the tablet preferably contains one or more nonionic surfactants, for example low foaming nonionic surfactants. The surfactants are amphiphilic molecules, which are composed of an apolar lipophilic part and a polar hydrophilic part.

For detergent tablets for dishwashers, the amount of surfactants in the tablet is preferably in the range of 0.05% to 20% by weight, and more preferably in the range of 1% to 5% by weight.

Surfactants in solid form are easier to use in tablets which also have solid compositions. However, when the surfactant is in liquid form, it can also be introduced into the tablet, in which case it is adsorbed on supports such as sodium carbonate or silica.

The synthetic nonionic surfactants may be generally defined as compounds derived from the condensation between alkylene oxide groups and hydrophobic organic compounds, which may be aliphatic or aromatic. The length of the hydrophilic portion of the surfactant can be easily adjusted to obtain a water-soluble compound having the desired HLB, the HLB translating the degree of hydrophilicity or lipophilicity of the surfactant.

The non-exhaustive list of nonionic surfactants that can be used in the tablet includes ethoxylated and / or propoxylated fatty alcohols, copolymer of ethylene oxide and propylene oxide, and alkyl polyglucoside, modified polyglycol ether alcohol.

It is also possible to use anionic surfactants, especially to improve the drying of dishes for dishwasher tablets. In this case, the amount of anionic surfactants present in the tablet is preferably between 0.05% and 40% by weight, and preferably between 1% and 20% by weight.

The non-exhaustive list of anionic surfactants that can be used in detergent tablets includes alkylbenzene sulfonates, paraffin-or alkanesulfonates, primary alcohol sulfates, α-olefinsulfonates, alkyl ether sulfates, sulfosuccinates, acyl isethionates, methyl ester sulfonates, soap, sulfoalkylamides. fatty acids, diglycolamide sulfates, N-acyl amino acids, and alkyl polyoxyethylene carboxylates.

Complementary components

In addition to these basic components of the detergent tablet, this may include additional components that will be used according to the desired specificities of the detergent tablet.

For example, protective additives such as benzotriazole and zinc salts may be used. These additives form a dishwashing and dishwasher protection system against unwanted chemical attack from either component of the tablet.

Chelating agents for trapping metal ions may also be present in the composition. They are also known as sequestering agents or complexing metal ions. If necessary, it is preferable that the amount of chelating agents is of the order of 0.5% to 20% by weight, and preferably 0.5% to 5% by weight. Preferred chelating agents include organic phosphonates, amino carboxylates, polyfunctionally substituted compounds, and mixtures thereof. It is also possible to use homopolymers of acrylic acid or copolymers of acrylic and maleic acid.

It can also be used bursting agents, which are intended to accelerate the disintegration of the layer in which they are incorporated. Preferred bursting agents include carboxymethylcellulose, crosslinked carboxymethylcellulose, croscarmellose sodium, cellulose, polyvinylpyrrolidone and mixtures thereof.

Dyes can also be added to differentiate the layers from each other. These dyes are essentially intended to improve the aesthetic appearance of the tablet vis-à-vis the consumer.

You can also add perfume to mask odors when opening the dishwasher.

We can also add pastilles additives such as binders that can increase the hardness of the pellet and reduce its friability. Among the binders that can be used include polyethylene glycol.

Lubricants can also be used to facilitate ejection of the tablet at the output of the rotary press. Among the lubricants that can be used include alkali metal stearates such as calcium stearate and magnesium stearate.

Other additives could be used such as anti-foaming agents.

Water-soluble coating that coats the body of the detergent tablet

Once the main body constituting the detergent tablet is formed, a particular solution is used to form the water-soluble coating, or coating, intended to cover the surface of the tablet.

As will be seen later in the comparative tests, this coating coming to coat the body of the detergent tablet has other advantages than that of protecting the body against shocks and against the humidity present in the ambient air. Indeed, he is going allow for example to improve the action of the detergent tablet, particularly with regard to rinsing. It will also participate in the overall stability of the detergent tablet while providing better disintegration and low friability of the body.

As indicated above, the solution used to form the water soluble coating contains a film forming agent, water and a specific agent to improve the rinsing efficiency of the detergent tablet.

As a film-forming agent, the solution may for example comprise polyvinyl alcohol (PVA).

The PVAs that can be used preferably have a degree of hydrolysis greater than or equal to 40% (mol%), preferably between 70% and 98% (mol%), and more preferably a degree of hydrolysis between 80% and 90%.

The PVAs used preferably have a molar mass (Mw) of between 10,000 g / mol and 200,000 g / mol, and more preferably between 15,000 g / mol and 100,000 g / mol. The mass molar mass of the PVA strongly impacts the final viscosity of the coating solution.

It is possible, for example, to use the PVA sold under the reference "Mowiol" by the company Clariant, as more particularly the products referenced "Mowiol 4-88" or "Mowiol 8-88".

The coating solution may contain PVA in a proportion of between 5% and 80% by weight relative to the total weight of the coating solution, preferably between 20% and 60% by weight relative to the total weight of the coating solution. coating, and more preferably between 30% and 55% by weight relative to the total weight of the coating solution.

A humectant may further be used in the solution to form the water-soluble coating. Humectants especially prevent water from migrating into the tablet.

Such a humectant is for example selected from glycerine, polyethylene glycol, and their combination.

Among the polyethylene glycols which can be used, those with a molar mass of between 1000 g / mol and 4000 g / mol are preferably chosen.

The coating solution may contain humectants in a proportion of less than or equal to 25% by weight relative to the total weight of the coating solution, preferably in a proportion of between 1% and 20% by weight relative to the total weight. of the coating solution, and more preferably a proportion of between 2% and 10% by weight relative to the total weight of the coating solution.

The specific agent for improving the rinsing efficiency is preferably an anti-spotting and / or anti-filming agent.

The anti-spotting agents make it possible to eliminate or limit the appearance of spotting, that is to say traces, in particular by avoiding the nucleation of drops of water on the surface of the glass or dishes.

The anti-filming agents make it possible to limit or eliminate the appearance of filming, that is to say the appearance of a film or white deposit.

The coating solution preferably contains specific agents in a proportion of between 0.05% and 50% by weight relative to the total weight of the coating solution, and more preferably between 2% and 20% by weight relative to the total weight of the coating solution.

Preferably, the specific agents for improving the rinsing efficiency are specific polymers, preferably polymers having an anti-spotting and / or anti-filming action.

As an anti-spotting agent, it is possible for example to choose a compound from carboxylate polymers, hydrophobic modified carboxylate polymers, in particular HASE polymers, and combinations thereof. For example, one of the products marketed by the Dow Chemical Company can be used under the references "acusol 820", "acusol 460" or "acusol 460ND".

As an anti-spotting agent, it is also possible to choose a compound among the hydrophobic modified acrylic / styrene copolymers. One can for example use one of the products marketed by AkzoNobel under the references "alcosperse 725", "alcosperse 747", or "alcosperse 747D".

As an anti-filming agent, one can for example choose a compound among the copolymers of acrylic acid and of sulfonated monomer. One can for example use one of the products marketed by AkzoNobel under the references "alcopserse 240", "alcosperse 240D", "alcoguard 4100D", "alcoguard 4160", or "alcoguard 4160".

As an anti-filming agent, it is also possible to choose a compound among the copolymers of acrylic acid and of sulfonic acid. For example, the product marketed by Dow Chemical under the reference "acusol 588G" may be used.

As an anti-filming agent, it is also possible to choose a compound among the copolymers of acrylic acid and maleic acid. For example, the product referred to as "acusol 497NG" marketed by Dow Chemical may be used, the product referenced "alcosperse175ND" marketed by AkzoNobel, or the product referenced "Sokalan CP42" marketed by BASF.

The coating solution may also contain a bittering agent such as denatonium benzoate and / or perfume.

The rest of the solution is water.

The various compounds are mixed at room temperature to form the solution for forming the coating of the detergent tablet.

The resulting mixture is for example sprayed on the surface of the body forming the detergent tablet, preferably at room temperature using a nozzle system.

The thickness of the coating deposited on the surface of the detergent tablet is for example between 0.05 μm and 1000 μm, preferably between 5 μm and 300 μm, and more preferably between 15 μm and 150 μm.

The water-soluble coating deposited on the tablet preferably represents between 0.5% and 15% of the total mass of the detergent tablet, and more preferably between 2% and 5% of the mass of the tablet.

Comparative tests Test 1: Spraying the coating solution on a tablet

The objective of this test is to compare the disintegration time and friability of a coated tablet, that is to say coated with a water-soluble coating, and a non-coated tablet, that is to say say without coating.

The compounds used in the formula of each tablet are divided into three layers. These compounds are shown in Table 1 below.

The different layers of the tablet are compressed on a hydraulic press so as to form a tablet having an overall mass of 16 g. The pre-compression and compression forces used are shown in Table 3 below.

The formulas made are shown in Table 1 below. <i> Table 1 </ i> Raw material Tablet n ° 1 Non-coated tablet (% by mass) Tablet n ° 2 Coated tablet (% by mass) Sodium carbonate 18.98 18.96 Sodium chloride 18.46 22.87 Sodium citrate 17.32 17.32 Blue dye 0.01 0.00 Yellow dye 0.01 0.00 Glucopon 50G (nonionic surfactant sold by the company BASF) 1.34 1.34 Sodium hedphosphonate 0.49 0.49 Acrylic homopolymer 0.86 0.85 protease 1.21 1.21 Arbocel TF0210 (marketed by JRS Rettenmeier) 0.61 0.00 Sodium percarbonate 13,03 13,03 PEG 1500 (polyethylene glycol) 4.76 1.00 Sodium silicate 4.92 4.92 Sodium sulphate 13.52 13.52 DAT 3.19 3.19 Glycerin 0.78 0.78 amylase 0.20 0.20 Dehypon GRA (nonionic surfactant sold by the company BASF) 0.33 0.33 TOTAL 100.00 100.00

• PEG 1500 qui est un additif de pastillage (liant) : 1% versus 4.76%
• Arbocel TF0210 qui est un agent désintégrant: 0% versus 0.61%

As shown in Table 1, the coated tablet (tablet # 2) is identical to the uncoated tablet (tablet # 1), except for the following ingredients:

• PEG 1500 which is a pelletizing additive (binder): 1% versus 4.76%
• Arbocel TF0210 which is a disintegrating agent: 0% versus 0.61%

For the coated tablet, the composition of the solution to form the water-soluble coating is summarized in Table 2 below. A uniform coating with a total mass of 0.4 g is deposited on the surface of the tablet so as to form a coating. <i> Table 2 </ i> Raw material Coating solution (% by weight) Polyvinyl alcohol 45.84 Water 47.91 Glycerin 0 Acusol 460 ND 6.25

Once the two types of tablets were formed, several comparative tests were carried out, in particular to measure the hardness, the disintegration, and the friability of the tablets.

The hardness of the tablets was measured on an MTS durometer.

The disintegration time of the tablets obtained was measured on equipment that goes back and forth with a frequency of 60 strokes / min. The shelves are placed in a basket with multiple holes to let the water through. The baskets are then soaked in 1.8L beakers of water at 30 ° C. The disintegration time is noted a once the tablet is completely disintegrated and there are no more tablet residues in the basket.

• nombre de tour: 50
• vitesse : 25 tours/min

The friability of the tablets is measured on the friability test device bearing the reference "FT2" and marketed by the company SOTAX, with the following rotation parameters:

• number of turns: 50
• speed: 25 rpm

The results of the comparative tests are summarized in Table 3 below. <i> Table 3 </ i> Pre-compression force (kN) Compression force (kN) Tablet hardness (N) Disintegration time (min) % friability Tablet n ° 1 (uncoated) 20 60 90 7 12 Tablet # 2 (Coated) 10 40 32 3 0.2

• de réduire la quantité d'additif de pastillage (liant, agent désintégrant) dans la formule ;
• de réduire les forces de pré-compression et compression sur les presses ;
• de diminuer le temps de délitement des tablettes ;
• tout en obtenant des tablettes moins friables, c'est-à-dire plus stables dans le temps, notamment en conditions de stockage.

It can be seen from the results of the comparative tests recapitulated in Table 3 that the use of the water-soluble coating makes it possible:

• to reduce the amount of pelletizing additive (binder, disintegrant) in the formula;
• reduce pre-compression and compression forces on presses;
• to reduce the disintegration time of tablets;
• while obtaining less friable tablets, that is to say, more stable over time, especially in storage conditions.

Test 2 : Use of an anti-spotting agent in the coating solution to improve the rinsing efficiency of a dishwasher tablet

The objective of this test is to evaluate the influence of the use of a coating incorporating an anti-spotting agent on the rinsing efficiency of the tablets.

• une tablette lave-vaisselle non-coatée avec l'agent anti-spotting dans la couche centrale (tablette n°3) ;
• une tablette lave-vaisselle coatée avec l'agent anti-spotting dans la couche centrale, où la solution de coating ne contient pas l'agent anti-spotting. La solution de coating est composée d'alcool polyvinylique et d'eau (tablette n°4) ;
• une tablette lave-vaisselle coatée avec l'agent anti-spotting dans la couche centrale, où la solution de coating ne contient pas l'agent anti-spotting. La solution de coating est composée d'alcool polyvinylique, d'eau, et d'un agent humectant (tablette n°5) ;
• une tablette lave-vaisselle enrobée d'une solution de coating contenant l'agent anti-spotting, où la formulation de la tablette ne contient pas l'agent anti-spotting. La solution de coating est composée d'alcool polyvinylique, d'eau, et de l'agent anti-spotting (tablette n°6)
• une tablette lave-vaisselle enrobée d'une solution de coating contenant l'agent anti-spotting, où la formulation de la tablette ne contient pas l'agent anti-spotting. La solution de coating est composée d'alcool polyvinylique, d'eau, d'un agent humectant et de l'agent anti-spotting (tablette n°7).

Comparative measurements have been made on the following dishwasher tablets:

• a dishwasher dish not coated with the anti-spotting agent in the central layer (tablet n ° 3);
• a dishwasher tablet coated with the anti-spotting agent in the central layer, where the coating solution does not contain the anti-spotting agent. The coating solution is composed of polyvinyl alcohol and water (tablet # 4);
• a dishwasher tablet coated with the anti-spotting agent in the central layer, where the coating solution does not contain the anti-spotting agent. The solution coating is composed of polyvinyl alcohol, water, and a humectant (tablet # 5);
• a dishwasher tablet coated with a coating solution containing the anti-spotting agent, wherein the formulation of the tablet does not contain the anti-spotting agent. The coating solution is composed of polyvinyl alcohol, water, and anti-spotting agent (tablet n ° 6)
• a dishwasher tablet coated with a coating solution containing the anti-spotting agent, wherein the formulation of the tablet does not contain the anti-spotting agent. The coating solution is composed of polyvinyl alcohol, water, a humectant and anti-spotting agent (tablet # 7).

The anti-spotting agent used for this comparative test is the product referred to as "acusol 460ND" marketed by Dow Chemical.

The compounds used in the formula of each tablet are divided into three layers. The compounds of the different layers are shown in Tables 4a, 4b and 4c below.

The different layers of the tablet are compressed on a hydraulic press so as to form a tablet having an overall mass of 16 g. The pre-compression and compression forces used are shown in Table 6 below. <i> Table 4a </ i> Ingredients LAYER 1 Tablet n ° 3 (% by mass of the layer) Tablet 4 (% by weight of the layer) Tablet n ° 5 (% by weight of the layer) Tablet n ° 6 (% by mass of the layer) Tablet 7 (% by weight of the layer) SODIUM CARBONATE 11.80 11.80 11.80 11.80 11.80 TRISODIC CITRATE 2 (H2O) 40,45 40,45 40,45 40,45 40,45 SODIUM PERCARBONATE 23.27 23.27 23.27 23.27 23.27 SODIUM CHLORIDE 14.56 14.56 14.56 14.56 14.56 LUTENSOL AT50 (nonionic surfactant sold by the company BASF) 2.98 2.98 2.98 2.98 2.98 ARBOCEL TF 0210 0.86 0.86 0.86 0.86 0.86 PEG 1500 5.00 5.00 5.00 5.00 5.00 SODIUM HEDPHOSPHONATE 0.88 0.88 0.88 0.88 0.88 GLYCERIN 0.20 0.20 0.20 0.20 0.20 TOTAL LAYER 1 100.00 100.00 100.00 100.00 100.00 Ingredients LAYER 2 Tablet n ° 3 (% by mass of the layer) Tablet 4 (% by weight of the layer) Tablet n ° 5 (% by weight of the layer) Tablet n ° 6 (% by mass of the layer) Tablet 7 (% by weight of the layer) SODIUM CARBONATE 11.77 11.77 11.77 11.77 11.77 TRISODIC CITRATE 2 (H2O) 40,45 40,45 40,45 40,45 40,45 SODIUM PERCARBONATE 23.27 23.27 23.27 23.27 23.27 SODIUM CHLORIDE 13.98 13.98 13.98 14.56 14.56 LUTENSOL AT50 (nonionic surfactant sold by the company BASF) 2.98 2.98 2.98 2.98 2.98 ARBOCEL TF 0210 0.86 0.86 0.86 0.86 0.86 PEG 1500 5.00 5.00 5.00 5.00 5.00 SODIUM HEDPHOSPHONATE 0.88 0.88 0.88 0.88 0.88 ACUSOL 460ND 0.58 0.58 0.58 0 0 TARTRAZINE COLOR E102 ® LA 0.03 0.03 0.03 0.03 0.03 GLYCERIN 0.20 0.20 0.20 0.20 0.20 TOTAL LAYER 2 100.00 100.00 100.00 100.00 100.00 Ingredients LAYER 3 Tablet n ° 3 (% by mass of the layer) Tablet 4 (% by weight of the layer) Tablet n ° 5 (% by weight of the layer) Tablet n ° 6 (% by mass of the layer) Tablet 7 (% by weight of the layer) SODIUM CARBONATE 13,10 13,10 13,10 13,10 13,10 SODIUM SILICATE 8.80 8.80 8.80 8.80 8.80 TRISODIC CITRATE 2 (H2O) 27,80 27,80 27,80 27,80 27,80 Lemon perfume 0.06 0.06 0.06 0.06 0.06 LUTENSOL AT50 (nonionic surfactant sold by the company BASF) 2.98 2.98 2.98 2.98 2.98 SODIUM CHLORIDE 29.85 29.85 29.85 29.85 29.85 ARBOCEL TF 0210 0.86 0.86 0.86 0.86 0.86 DAT 4.00 4.00 4.00 4.00 4.00 CATALYST 0.76 0.76 0.76 0.76 0.76 Protease 4.65 4.65 4.65 4.65 4.65 AMYLASE 0.78 0.78 0.78 0.78 0.78 PEG 1500 6.13 6.13 6.13 6.13 6.13 BLUE COLOR E133 LAKE 0.03 0.03 0.03 0.03 0.03 GLYCERIN 0.20 0.20 0.20 0.20 0.20 TOTAL LAYER 3 100.00 100.00 100.00 100.00 100.00

For tablets No. 4, No. 5, No. 6 and No. 7, a coating solution is sprayed on the surface of tablets thus formed to coat the tablet with a water-soluble coating.

Table 5 below specifies the composition of the coating solution used for these tablets No. 4, No. 5, No. 6 and No. 7. <i> Table 5 </ i> Ingredients solution coating Tablet # 4 (% by weight) Tablet # 5 (% by weight) Tablet # 6 (% by weight) Tablet # 7 (% by weight) Polyvinyl alcohol 47,90 47,90 45.84 45.84 Water 52.10 50,10 47.91 46.91 Glycerin 0 2.00 0 1.00 Acusol 460 ND 0 0 6.25 6.25 TOTAL 100.00 100.00 100.00 100.00

For tablets # 4 and # 5, a uniform coating of 0.4 g of coating solution is deposited on the surface of the tablet to form a uniform coating.

For tablets # 6 and # 7, a uniform coating of 0.465 g of coating solution is deposited on the surface of the tablet to form a uniform coating.

Each of tablets No. 3, No. 4, No. 5, No. 6 and No. 7 thus manufactured comprise the same amount of anti-spotting agent, namely 0.029 g of "Acusol 460 ND" product.

Table 6 below summarizes the manufacturing parameters of the different tablets, and gives the measurements of hardness and disintegration of each of the tablets, it being understood that these parameters were measured in the same way as for the test 1. <i> Table 6 </ i> Tablet n ° 3 Tablet n ° 4 Tablet n ° 5 Tablet n ° 6 Tablet n ° 7 Mass layer 1 (g) 6 6 6 6 6 Mass layer 2 (g) 5 5 5 5 5 Mass layer 3 (g) 5 5 5 5 5 Pre-compression force applied on layer 1 (kN) 20 30 30 30 30 Pre-compression force applied on layer 2 (kN) 20 20 20 20 20 Compression force applied on layer 3 (kN) 60 30 30 30 30 Tablet hardness (N) 135 52 51 48 49 Disintegration time (min: sec) of the tablet without coating 7min: 30sec 4min: 40sec 4min: 30sec 4min: 10sec 4min: 05sec

In addition, tests were carried out to evaluate the associated rinsing efficiency for each of tablets # 3, # 4, # 5, # 6 and # 7.

The tests to measure the rinsing efficiency of the tablets were carried out with a Fagor LFF-041 dishwasher programmed in a short wash cycle (30 minutes) at 35 ° C and a water hardness of 35 ° C. TH.

For this test, 4 cup glasses are placed on the top compartment of the dishwasher at the beginning of the wash cycle. A dirt ballast is also placed in the dishwasher.

The rinsing efficiency of the tablets is evaluated by observation of the glasses using a box with spots.

Spotting is measured after a wash cycle. Spotting is rated on a scale of scores between 0 and 7, where 0 is the worst score (ineffective rinse) and 7 is the best rating (very effective rinse).

The filming is measured after 5 successive washing cycles. The filming is evaluated by observation of the veil present on the glasses. Filming is rated with a rating scale between 0 and 10, where 0 is the worst rating (ineffective rinsing) and 10 is the best rating (very effective rinsing).

The gloss is evaluated after 1 wash cycle. The brilliance is evaluated thanks to the scale of notes of 0 to 10, where 0 is the worst note (ineffective rinsing) and 10 is the best note (rinsing very effective).

The results of the comparative tests are summarized in Table 7 below. <i> Table 7 </ i> coating spotting Filming brightness Tablet n ° 3 NO 5 9 10 Tablet n ° 4 YES without Acusol 460ND 5.5 9 10 Tablet n ° 5 YES without Acusol 460ND 5.5 9 10 Tablet n ° 6 YES with Acusol 460ND 6.5 9 10 Tablet n ° 7 YES with Acusol 460ND 6.5 9 10

It is found that tablets # 5 and # 6 have better results on spotting than tablets # 3, # 4 and # 5.

The addition of the anti-spotting agent (Acusol 460 ND) in the coating solution therefore makes it possible to increase the rinsing efficiency on the short cycle spotting.

The rapid dispersion of the anti-spotting agent (Acusol 460 ND) in the washing solution makes it possible to improve the efficiency on the spotting of the tablet.

Test 3 : Use of an anti-spotting polymer in the coating solution to improve the stability of a dishwasher tablet

The objective of this test is to evaluate the influence of the use of a coating incorporating an anti-spotting agent on the shelf stability.

• une tablette lave-vaisselle non-coatée étant emballée individuellement dans un emballage hydrosoluble, de type flowpack hydrosoluble (tablette n°8) ;
• une tablette lave-vaisselle coatée, où la solution de coating ne contient pas d'agent anti-spotting. La solution de coating est composée d'alcool polyvinylique et d'eau (tablette n°9) ;
• une tablette lave-vaisselle coatée, où la solution de coating ne contient pas d'agent anti-spotting. La solution de coating est composée d'alcool polyvinylique, d'eau, et d'un agent humectant (tablette n°10) ;
• une tablette lave-vaisselle enrobée d'une solution de coating contenant un agent anti-spotting. La solution de coating est composée d'alcool polyvinylique, d'eau, et de l'agent anti-spotting (tablette n°11) ;
• une tablette lave-vaisselle enrobée d'une solution de coating contenant un agent anti-spotting. La solution de coating est composée d'alcool polyvinylique, d'eau, d'un agent humectant et de l'agent anti-spotting (tablette n°12).

Comparative measurements have been made on the following dishwasher tablets:

• a non-coated dishwashing tablet being individually wrapped in a water-soluble, water-soluble flowpack (tablet # 8);
• a coated dishwasher tablet, where the coating solution does not contain an anti-spotting agent. The coating solution is composed of polyvinyl alcohol and water (tablet n ° 9);
• a coated dishwasher tablet, where the coating solution does not contain an anti-spotting agent. The coating solution is composed of polyvinyl alcohol, water, and a humectant (tablet # 10);
• a dishwasher tablet coated with a coating solution containing an anti-spotting agent. The coating solution is composed of polyvinyl alcohol, water, and anti-spotting agent (tablet # 11);
• a dishwasher tablet coated with a coating solution containing an anti-spotting agent. The coating solution is composed of polyvinyl alcohol, water, a humectant and anti-spotting agent (tablet # 12).

The anti-spotting agent used for this comparative test is the product referred to as "acusol 460ND" marketed by Dow Chemical.

The compounds used in the formula of each tablet are divided into three layers. The compounds of the different layers are shown in Tables 8a, 8b and 8c below.

The different layers of the tablet are compressed on a hydraulic press so as to form a tablet having an overall mass of 16 g. The pre-compression and compression forces used are shown in Table 10 below. <i> Table 8a </ i> Ingredients LAYER 1 Tablet n ° 8 (% by mass of the layer) Tablet 9 (% by weight of the layer) Tablet n ° 10 (% in mass of the layer) Tablet n ° 11 (% by mass of the layer) Tablet 12 (% by weight of the layer) SODIUM CARBONATE 11.80 11.80 11.80 11.80 11.80 TRISODIC CITRATE 2 (H2O) 40,45 40,45 40,45 40,45 40,45 SODIUM PERCARBONATE 23.27 23.27 23.27 23.27 23.27 SODIUM CHLORIDE 14.56 14.56 14.56 14.56 14.56 LUTENSOL AT50 (nonionic surfactant sold by the company BASF) 2.98 2.98 2.98 2.98 2.98 ARBOCEL TF 0210 0.86 0.86 0.86 0.86 0.86 PEG 1500 5.00 5.00 5.00 5.00 5.00 SODIUM HEDPHOSPHONATE 0.88 0.88 0.88 0.88 0.88 GLYCERIN 0.20 0.20 0.20 0.20 0.20 TOTAL LAYER 1 100.00 100.00 100.00 100.00 100.00 Ingredients LAYER 2 Tablet n ° 8 (% by mass of the layer) Tablet 9 (% by weight of the layer) Tablet n ° 10 (% in mass of the layer) Tablet n ° 11 (% by mass of the layer) Tablet 12 (% by weight of the layer) SODIUM CARBONATE 11.77 11.77 11.77 11.77 11.77 TRISODIC CITRATE 2 (H2O) 40,45 40,45 40,45 40,45 40,45 SODIUM PERCARBONATE 23.27 23.27 23.27 23.27 23.27 SODIUM CHLORIDE 14.56 14.56 14.56 14.56 14.56 LUTENSOL AT50 (nonionic surfactant sold by the company BASF) 2.98 2.98 2.98 2.98 2.98 ARBOCEL TF 0210 0.86 0.86 0.86 0.86 0.86 PEG 1500 5.00 5.00 5.00 5.00 5.00 SODIUM HEDPHOSPHONATE 0.88 0.88 0.88 0.88 0.88 TARTRAZINE COLOR E102 ® LA 0.03 0.03 0.03 0.03 0.03 GLYCERIN 0.20 0.20 0.20 0.20 0.20 TOTAL LAYER 2 100.00 100.00 100.00 100.00 100.00 Ingredients LAYER 3 Tablet n ° 8 (% by mass of the layer) Tablet 9 (% by weight of the layer) Tablet n ° 10 (% in mass of the layer) Tablet n ° 11 (% by mass of the layer) Tablet 12 (% by weight of the layer) SODIUM CARBONATE 13,10 13,10 13,10 13,10 13,10 SODIUM SILICATE 8.80 8.80 8.80 8.80 8.80 TRISODIC CITRATE 2 (H2O) 27,80 27,80 27,80 27,80 27,80 Lemon perfume 0.06 0.06 0.06 0.06 0.06 LUTENSOL AT50 (nonionic surfactant sold by the company BASF) 2.98 2.98 2.98 2.98 2.98 SODIUM CHLORIDE 29.85 29.85 29.85 29.85 29.85 ARBOCEL TF 0210 0.86 0.86 0.86 0.86 0.86 DAT 4.00 4.00 4.00 4.00 4.00 CATALYST 0.76 0.76 0.76 0.76 0.76 Protease 4.65 4.65 4.65 4.65 4.65 AMYLASE 0.78 0.78 0.78 0.78 0.78 PEG 1500 6.13 6.13 6.13 6.13 6.13 BLUE COLOR E133 LAKE 0.03 0.03 0.03 0.03 0.03 GLYCERIN 0.20 0.20 0.20 0.20 0.20 TOTAL LAYER 3 100.00 100.00 100.00 100.00 100.00

Each of the manufactured tablets # 8 are individually wrapped in a water-soluble flowpack. Such a water-soluble flowpack is a package formed from polyvinyl alcohol, of thickness 35 μm, such as for example the product referenced "L711" marketed by the company MonoSol.

For tablets No. 9, No. 10, No. 11 and No. 12, a coating solution is sprayed on the surface of tablets thus formed to coat the tablet with a water-soluble coating. For these tablets, a uniform coating of 0.5 g coating solution is deposited on the surface of the tablet to form a uniform coating.

Table 9 below specifies the composition of the coating solution used for these tablets No. 9, No. 10, No. 11 and No. 12. <i> Table 9 </ i> Ingredients solution coating Tablet n ° 9 (% in mass) Tablet # 10 (% by weight) Tablet n ° 11 (% in mass) Tablet # 12 (% by weight) Polyvinyl alcohol 47,90 47,90 45.84 45.84 Water 52.10 50,10 47.91 46.91 Glycerin 0 2.00 0 1.00 Acusol 460 ND 0 0 6.25 6.25 TOTAL 100.00 100.00 100.00 100.00

Table 10 below summarizes the manufacturing parameters of the various tablets, and gives the measurements of hardness and disintegration of each of the tablets, it being understood that these parameters were measured in the same way as for the test 1. <i> Table 10 </ i> Tablet n ° 8 Tablet n ° 9 Tablet n ° 10 Tablet n ° 11 Tablet n ° 12 Mass layer 1 (g) 6 6 6 6 6 Mass layer 2 (g) 5 5 5 5 5 Mass layer 3 (g) 5 5 5 5 5 Pre-compression force applied on layer 1 (kN) 20 30 30 30 30 Pre-compression force applied on layer 2 (kN) 20 20 20 20 20 Pre-compression force applied on layer 3 (kN) 60 30 30 30 30 Tablet hardness (N) 135 50 49 51 50 Disintegration time (min: sec) of the tablet without coating and without flowpack 7min 20sec 4min 52sec 4min 50sec 5min 00sec 5min 05sec

For test 3, 5 copies of each of tablets No. 8, No. 9, No. 10, No. 11 and No. 12 are used and these 5 are placed in a flexible bag whose shape is provided. for the bag to stand alone, for example a Doypack type bag.

Each flexible bag containing the 5 copies of each of the different tablets is then placed in a climatic chamber at 38 ° C. and 70% relative humidity for 2 weeks.

After these two weeks spent in climate chamber, each tablet is tested to examine the visual appearance and measure the disintegration time of each type of tablet.

The results obtained are summarized in Table 11 below. <i> Table 11 </ i> Tablet n ° 8 Tablet n ° 9 Tablet n ° 10 Tablet n ° 11 Tablet n ° 12 Tablet appearance Presence of some pustules and beginning of lamination Presence of some pustules and beginning of lamination Presence of some pustules and beginning of lamination Good visual appearance, absence of pustules and lack of lamination Good visual appearance, absence of pustules and lack of lamination Disintegration time (min: sec) 7min: 40sec 8min: 10sec 8min: 00sec 9min: 00sec 8min: 55sec

It is noted that the appearance of tablets 11 and 12 has not been altered compared to tablets 8, 9 and 10 which have some pustules and a start of lamination after two weeks in the climatic chamber . This proves that the coating incorporating the specific agent to improve the rinsing efficiency comes, surprisingly, to improve the stability of the tablet, including with respect to a tablet also having a coating but which does not include the agent. specific.

Furthermore, it is found that the disintegration time tablets 11 and 12 is consistent and substantially identical to the disintegration time of other types of tablets.

BIBLIOGRAPHIC REFERENCES

• US 3,231,505
• WO 01/64829
• EP 2 196 531

Claims (17)

1. Detergent tablet comprising a body made from compacted powder, said body being coated with a water-soluble coating, said water-soluble coating having a composition comprising a film-forming agent and water, characterised in that the composition of the water-soluble coating further comprises at least one specific agent for improving the efficiency in terms of rinsing of the detergent tablet.
2. Detergent tablet according to claim 1, wherein the water-soluble coating has a thickness comprised between 1 µm and 1,000 µm, preferably comprised between 5 µm and 300 µm, and further preferably comprised between 15 µm and 150 µm.
3. Detergent tablet according to any of claims 1 or 2, wherein the water-soluble coating has a weight representing between 0.5% to 15% by weight compared to the total weight of the detergent tablet, preferably between 2% to 5% by weight compared to the total weight of the detergent tablet.
4. Detergent tablet according to any of claims 1 to 3, wherein the specific agent for improving the efficiency in terms of rinsing is an anti-spotting and/or anti-filming agent.
5. Detergent tablet according to any of claims 1 to 4, wherein the at least one specific agent is in a proportion comprised between 0.05% and 50% by weight compared to the total weight of the composition of the water-soluble coating, preferably between 2% and 20% by weight compared to the total weight of the composition of the water-soluble coating.
6. Detergent tablet according to any of claims 1 to 5, wherein the at least one specific agent is a polymer.
7. Detergent tablet according to any of claims 1 to 6, wherein the at least one specific agent is selected from modified hydrophobic acrylic/styrene copolymers, or combinations thereof.
8. Detergent tablet according to any of claims 1 to 6, wherein the at least one specific agent is selected from copolymers of acrylic acid and sulphonated monomer, copolymers of acrylic acid and sulphonic acid, copolymers of acrylic acid and maleic acid, or combinations thereof.
9. Detergent tablet according to any of claims 1 to 6, wherein the at least one specific agent is selected from carboxylate polymers, modified hydrophobic carboxylate polymers, in particular HASE polymers, and combinations thereof.
10. Detergent tablet according to any of claims 1 to 9, wherein the film-forming agent is in a proportion comprised between 5% and 80% by weight compared to the total weight of the composition of the water-soluble coating, preferably comprised between 20% and 60% by weight compared to the total weight of the composition of the water-soluble coating, and further preferably comprised between 30% and 55% by weight compared to the total weight of the composition of the water-soluble coating.
11. Detergent tablet according to any of claims 1 to 10, wherein the film-forming agent is selected from polyvinyl alcohols.
12. Detergent tablet according to claim 11, wherein the film-forming agent is selected from polyvinyl alcohols having a hydrolysis level with a molar percentage greater than or equal to 40%, preferably comprised between 70% and 98%, and further preferably comprised between 80% and 90%.
13. Detergent tablet according to any of claims 11 or 12, wherein the film-forming agent is selected from polyvinyl alcohols having a molar mass by weight comprised between 10,000 g/mol and 200,000 g/mol, and preferably comprised between 15,000 g/mol and 100,000 g/mol.
14. Detergent tablet according to any of claims 1 to 13, wherein the composition of the water-soluble coating further comprises a humectant.
15. Detergent tablet according to claim 14, wherein the humectant is in a proportion less than or equal to 25% by weight compared to the total weight of the composition of the water-soluble coating, preferably in a proportion comprised between 1% and 20% by weight compared to the total weight of the composition of the water-soluble coating, further preferably in a proportion comprised between 2% and 10% by weight compared to the total weight of the composition of the water-soluble coating.
16. Detergent tablet according to any of claims 14 or 15, wherein the humectant is selected from glycerine, polyethylene glycols, and combinations thereof.
17. Detergent tablet according to any of claims 14 or 15, wherein the humectant is selected from polyethylene glycols having a molar mass by weight comprised between 1,000 g/mol and 4,000 g/mol.