FR2778666A1 - THREE-LAYER DETERGENT TABLET, AND USE - Google Patents

Abstract

A detergent tablet with a sandwich structure of at least three layers comprises: (1) two external layers comprising an antiscaling agent; and (2) an internal layer comprising a bleaching agent. The external layers dissolve faster than the internal layer and are retarding agents for the internal layer in order to pretreat the washing water against lime scale. The tablet dissolves in two steps: first the external layers, then the internal layer when the external layers are entirely dissolved. An Independent claim is also included for the manufacturing of the tablet.

Description

1 THREE-LAYER DETERGENT TABLET AND USE.

  The invention relates to a three-layer detergent tablet and to its use.

  Various kinds of detergent compositions are known for washing dishes in the machine.

  Powders or gels for dishwashers have thus been proposed, the quantity of which is measured empirically by the consumer, who places them in the dispenser of said dishwasher. This type of packaging is not satisfactory since the consumer most of the time uses too little or too much powder or gel, thus leading either to poor washing or to overconsumption of products. To solve this problem, so-called monolayer tablets have been proposed which consist of a mixture of components such as anti-scale agents, enzymatic system, bleaching agents, etc. However, this type of tablet has the disadvantage of leading to the more or less rapid and random dissolution of the 20 components depending on the cycle and the washing temperature. In addition, the technical effects of the components are combined in an irrational way. Furthermore and

  above all, it may be necessary to note the deposit of a white veil on the dishes, particularly apparent on the glasses, which suggests poor washing or rinsing and leads to a rapid and apparent deterioration in the quality of the dishes 25 and to the loss of the transparency effect of the glasses.

  To solve this problem, the document WO 97/03177 has proposed a multilayer tablet made up of at least two layers, one of which comprises

  a bleaching agent and a bleaching activator, while the other 30 includes an anti-corrosion agent.

  Even if this concept makes it possible to separate the two actions, respectively whitening and anticorrosion, one can be brought to note still the appearance of the

  white veil on dishes and glasses in particular. In other words, the anti-scale system did not play its role immediately, or at least insufficiently.

  The problem which the invention proposes to solve is to provide a multi-layer detergent tablet allowing an effective washing while avoiding in particular the deposit of a white veil on the dishes. Another problem which the invention proposes to solve is to provide a multi-layer tablet which remains stable during storage. We have indeed found

  that in the tablets proposed hitherto, the enzymatic system was degraded in particular by bleaching agents or the mixture of bleaching agents / bleaching activators.

  To solve all of these problems, the invention provides a detergent tablet of the multilayer type, characterized: - in that it consists of a sandwich structure in three superposed layers respectively: ò two external layers comprising in particular an anti- limestone, to a middle layer comprising in particular a bleaching agent, the outer layers having a dissolution time faster than that of the middle layer and having the function of constituting agents delaying the dissolution of the middle layer and therefore of its effects , in view of allowing an anti-scale pretreatment of the washing water and therefore obtaining pure water for the subsequent washing, - and in that the three-layer sandwich structure makes it possible to obtain a sequence for dissolving the tablet in two stages, namely: 25. first the dissolution of the two outer layers, then when the outer layers are completely dissolved, the

dissolution of the middle layer.

  In order to allow the rapid dissolution of the anti-scale agent, said agent

  anti-lime is hydrated, advantageously prehydrated. However, the anti

  limestone can also be anhydrous.

  According to an advantageous embodiment of the invention, the layers

  have an identical composition.

  In practice, the dissolution of the outer layers is carried out in a time range between two and seven minutes, advantageously three to five minutes. Likewise, the dissolution of the middle layer takes place in a time range between 8 and 16 minutes, advantageously 10 minutes. Furthermore, the dissolution time of each of the layers varies depending on the hardness of the pellet. In practice, the hardness of the tablet is chosen

  between 3 and 40 kilopascals (KP), advantageously at 10 to 25 KP.

  As already said, the tablet of the invention is in the form of three flat layers superimposed on each other by compaction of their most surface

  large. In this way, the dissolution of the apparent periphery of the intermediate layer during the first sequence is very limited.

  In practice, the weight of the tablet of the invention is approximately 20 grams, the weight of each of the layers being distributed as follows: outer layers of 5 to 7 g

- middle layer of 6 to 10 g.

  Preferably, the anti-scale agent is chosen from the group comprising tripolyphosphate, sodium citrate, organic phosphonates,

  aminopolyalkylenephosphonates, aminopolycarboxylates, homo and / or acidic and neutralized acrylic and maleic copolymers.

  To allow dirt to attack, the two outer layers include an enzymatic system made up of protease, amylase and lipase enzymes.30

  In addition, these outer layers may include an alkaline agent, a surfactant, an anti-tarnishing agent, in particular with regard to silverware.

  As already said, it is only when the two outer layers are

  dissolved, that the action of the middle layer begins.

  As a bleaching agent, a bleaching agent chosen from the group comprising sodium perborate mono or

  tetrahydrate, sodium percarbonate and sodium monopersulfate.

  However, to allow more effective dishwashing after removal of lime and dirt, the middle layer further includes a bleach activator selected from the group comprising tetraacetylene diamine (TAED), pentaacetylglucose (PAG), tetraacetylglycoluryl ( TAGU) .10 To allow complexing of metal ions and bring about dispersing effects, the middle layer further comprises a complexing agent chosen from the group comprising phosphonate or homopolymers of acrylic acid or copolymers of acrylic and maleic acid. To strengthen the washing activity, the middle layer includes

also an alkaline agent.

  To avoid the appearance of foam, the middle layer includes an agent

  surfactant with anti-foaming activity.

  Due to the separation of the enzymatic activity from that of bleaching, a very good storage stability of the tablet of the invention is observed. Of

  more, taking into account the fact that the peroxidizing medium is without free water, there is only very little risk of loss of active oxygen. In other words, the enzymatic system is not disturbed by the peroxidizing system.

  This optimized stability characteristic makes it possible to use much more peroxidizing bleaching agents of the sodium persulfate type or

still chlorinated compound.

  Finally, the invention also relates to the use of the detergent tablet for washing dishes.

  In practice, said tablet will be oval, parallelepipedic, prismatic truncated or not and pyramidal truncated or not so that it can be

  introduced into the door panel case.

  In fact, taking into account the fact that the tablet should only act during washing, it is recommended to introduce said tablet into the counter

dishwasher door.

  The characteristics of the invention and the advantages which flow therefrom

  The following exemplary embodiments will better emerge.

  In the following two exemplary embodiments, two different formulations of the tablet of the invention are proposed, with or without the presence of phosphate in the external layers (Example 1 and Example 2 respectively). Example 1: tablet with phosphate A tablet is prepared. detergent, the composition of the outer layer and the middle layer of which are as follows: composition of the outer layers as a percentage by weight of the final tablet: tripolyphosphate: 22 acrylic homopolymer (PM 4500): 1 protease: 0.75 amylase: 0, 75 colorant: surfactant traces: nonionic: 0.5 silicate / carbonate granule: 5 composition of the middle layer as a percentage by weight of the final phosphonate tablet: 0.85 soda perborate: 7.5 silicate / carbonate cogranules: 15, 44

TAED: 4

  non-ionic surfactant: 1 sodium disilicate: 10 perfume: 0.20 pastillage additive 1 The mass of the tablet obtained is 20 grams, the mass of each layer distributed as follows: - upper layer and lower layer: 6 grams - middle layer: 8 grams

  The hardness of the tablets obtained measured using a SCHLEUNIGER device is 14 KP.

  Dissolution tests are then carried out in a MIELE brand dishwasher under the following conditions: program without prewash at

 C, wash time 18 minutes.

  The dissolution times (in minutes) for each of the layers are shown in the table below.

TEST 1 TEST 2 TEST 3

  Dissolution time of the 12 1 1 12 middle layer dissolution time of the 4 5 4 upper layer dissolution time of the 5 4 4 lower layer Example 2: phosphate-free tablet The composition of each of the outer and middle layers is as follows: composition of the external layers as a percentage by weight of the final acrylic homopolymer tablet (PM 4500): 1.5 phosphonate: 0.425 protease: 0.85 amylase: 0.85 dye: non-ionic surfactant traces: 0.5 cogranulate carbonate silicate : 10.875 trisodium citrate: 15 ò composition of the middle layer in percentage by weight of the final tablet acrylic homopolymer (PM 4500): 3 sodium perborate: 12.5

TAED: 4

  non-ionic surfactant: 1 fragrance: 0.2 pellet additive: 1 sodium citrate: 5 co-granulated carbonate / silicate: 13.3

  The weight of the outer layers is 6 grams.

  The weight of the inner layer is 8 grams.

  The hardness of the tablets obtained measured using a

SCHLEUNIGER is 14 KP.

  Dissolution tests are then carried out in a MIELE brand dishwasher under the following conditions: program without prewash at

 C, wash time 18 minutes.

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  The dissolution times (in minutes) for each of the layers are shown in the table below.

TEST 1 TEST 2 TEST 3

  Dissolution time of the 14 15 15 middle layer dissolution time of the 5 6 5 upper layer dissolution time of the 6 5 6 lower layer

  The advantages of the invention appear clearly from the description.

  Note in particular the sequencing of the dissolution of the outer layers and of the middle layer making it possible to purify the washing water before washing

  proper and thus not to obtain a white veil on the dishes and in particular on the glasses.

  Note also the advantage of separating the outer layers based on anti-lime agents and enzymatic agents from the middle layer based on bleaching agents in order to optimize the stability of the tablet during its storage. .20

Claims (8)

  1 / Detergent tablet of the multilayer type characterized: - in that it consists of a sandwich structure in three superposed layers respectively: With two external layers comprising in particular an anti-scale agent, * a middle layer comprising in particular a bleaching agent , the outer layers having a faster dissolution time than that of the middle layer and having the function of constituting agents delaying the dissolution of the middle layer and therefore of its effects, in view of allowing an anti-lime pretreatment of the wash water and therefore obtaining pure water for subsequent washing, - and in that the three-layer sandwich structure makes it possible to obtain a sequence for dissolving the tablet in two stages, namely: first of all the dissolution of the two outer layers, then when the outer layers are completely dissolved, the dissolution of the middle layer.   2 / shelf according to claim 1, characterized in that the two   outer layers have an identical composition.   3 / Tablet according to claim 2, characterized in that the two outer layers further comprise an enzymatic system.   4 / Tablet according to one of claims 1 to 3, characterized in that the anti-scale agent is prehydrated and chosen from the group comprising   tripolyphosphate, sodium citrate, organic phosphonates, aminopolyalkylenephosphonates, aminopolycarboxylates, homo and / or acidic and neutralized acrylic and maleic copolymers. 30   / Tablet according to one of claims 1 to 4, characterized in that the bleaching agent is chosen from the group comprising sodium perborate   mono or tetrahydrate, sodium percarbonate and sodium monopersulfate.   6 / Tablet according to one of claims 1 to 5, characterized in that the dissolution of the outer layers is carried out in a time range included   between two and seven minutes, preferably between three minutes and five.   7 / Tablet according to one of claims 1 to 6, characterized in that the dissolution of the middle layer takes place in a time range included   between eight and sixteen minutes, preferably ten minutes.   8 / Tablet according to one of claims 1 to 7, characterized in that   the weight of each layer is distributed as follows: - outer layers: 5 to 7 g - middle layer: 6 to 10 g   9 / Tablet according to one of claims 1 to 8, characterized in that   the hardness of said tablet is chosen between 3 and 40 kilopascals.   / Use of shelves according to one of claims 1 to 9, for washing dishes.