EP0751212A1 - Use of carbonate-silicate-cogranulates as corrosion inhibitors in dishwashing detergents - Google Patents

Abstract

Use as alkaline agents, for reducing visible corrosion of glass and deterioration of decorations on glass and porcelain, in detergent compsn. (partic. for use in dishwashers) of co-granules comprising an alkali metal carbonate (I) and alkali silicate nSiO2.M2O (II) is new. M = alkali metal, esp. Na or K; n = 1.6-3.5, pref. 1.6-2.4. The co-granules have wt. ratio (dry basis) (I):(II) of 45:55-80:20, pref. 60:40-75:25, with wt. ratio water:silicate (dry basis) at least 33:100, pref. 40-120:100.

Description

The present invention relates to the use of cogranules based on alkali metal carbonate and on alkali metal silicate, as alkaline agents reducing visible corrosion of glass and decorations of glass or porcelain, in detergent compositions in particular for washing in the dishwasher.

Alkali metal silicates, in particular sodium silicates, are widely used in detergent compositions for dishwashers. They provide a buffering effect, detergent power and dispersing action in the detergent bath.

Metasilicates (SiO ₂ / M ₂ O ratio equal to 1 where M represents an alkali metal) have been particularly used in detergents for dishwashers because of their high detergent power. However, these high alkalinity products had the disadvantage of deteriorating the surface of the glass and degrading the decorations of glass or porcelain. It thus appeared, after a number of washes with these detergents, a frosted glass, colored iridescence, white streaks or a continuous whitish veil on the glass, as well as a deterioration of the decorations. They have been gradually replaced by disilicates (SiO ₂ / M ₂ O ratio equal to 2) which have the advantages of the alkaline metasilicates listed above. However, even if these disilicates have a lower alkalinity than metasilicates, they still do not sufficiently protect the glass and the decorations against corrosion.

In certain compositions, the silicates have been replaced by sodium tripolyphosphates, which perform functions equivalent to those of the silicates and which protect the glass against temporary deposits, particularly deposits of calcium carbonate. However, tripolyphosphates also have the disadvantage of causing corrosion of the glass and the decorations. Indeed, due to their complexing power of calcium, they contribute to the surface rupture of the glass network by passage of the calcium in solution, which accelerates the corrosion of the glass; similarly, their complexing or sequestering power of heavy metals leads to the degradation of glass and porcelain decorations. In addition, tripolyphosphates are used less and less in detergents due to environmental standards.

The Applicant has described (EP-A-488,868 and EP-A-637,626) the use of cogranules based on sodium carbonate and sodium silicate, or potassium siliconate optionally as a mixture with said cogranules, as agents reducers of temporary lime deposit ("anti-filming" agents) in detergent compositions for automatic dishwashing.

The Applicant has now found that said cogranules based on sodium carbonate and sodium silicate can be used in detergent compositions as alkaline agents reducing the visible corrosion of glass and glass and porcelain decorations, corrosion which can occur during successive washings in a dishwasher.

• l'irisation correspondant à une colorisation locale ou totale de la surface du verre, colorisation s'intensifiant avec les lavages et pouvant conduire à la formation d'un voile blanchâtre permanent
• et les rayures permanentes s'intensifiant avec les lavages et pouvant s'accompagner d'une perte de transparence locale ou totale (dépoli).

Dans le cas des décors de verre ou de porcelaine, cette corrosion se manifeste par une perte de la brillance, puis des couleurs, voire, au stade ultime, par une disparition totale des décors.The term “visible corrosion” of the glass and of the glass and porcelain decorations means any “visible” modification of the appearance of the surface of the glass and of the decorations, by comparison with an uncorroded reference sample.
In the case of glass, this corrosion corresponds to a chemical modification of certain elements of the surface of the glass in the detergent solution. This is a different phenomenon from that of the temporary deposit on the glass surface of a lime film (film which is eliminated for example using an acetic acid solution) or a film of organic products present in the detergent composition (film which is eliminated using an organic solvent, ethanol for example).
Visible corrosion of glass can manifest itself in two forms:

• the iridescence corresponding to a local or total colorization of the glass surface, colorization intensifying with the washes and which can lead to the formation of a permanent whitish veil
• and permanent scratches that intensify with washing and can be accompanied by a loss of local or total transparency (frosted).

In the case of glass or porcelain decorations, this corrosion manifests itself by a loss of gloss, then of colors, or even, at the final stage, by a total disappearance of the decorations.

The subject of the invention is the use, as alkaline agents reducing visible corrosion of glass and glass or porcelain decorations, in detergent compositions in particular for washing in the dishwasher, of co-granules comprising an alkali metal carbonate and an alkali metal silicate of formula nSiO ₂ , M ₂ O, formula in which M represents an alkali metal and n is of the order of 1.6 to 3.5, preferably of the order of 1.6 to 2,4, said co-granules having a weight ratio, expressed in dry terms, carbonate / silicate of the order of 45/55 to 80/20, preferably of the order of 60/40 to 75/25, with a weight ratio water / silicate expressed as dry at least about 33/100, preferably of the order of 40/100 to 120/100.

Among the cogranules which can be used, there may be mentioned in particular those forming the subject of European patent applications EP-A-488,868 and EP-A-561,656 and meeting the definition above. They are obtained by adsorption and / or absorption of an aqueous solution of hydrated alkali metal silicate, on a particulate support chemically inert with respect to the silicate, consisting of an alkali metal carbonate.

They are characterized in particular by their water content.

The amount of mineral support brought into contact with the silicate solution is adjusted so that the water / silicate weight ratio expressed as dry is at least 33/100. The upper limit of this ratio corresponds to the limits for which we keeps a silicate in powder form with fluid flow ("free flowing"), that is to say usable in detergency. This is advantageously less than or equal to about 120/100.

The preparation of the cogranules can be done by any available means of bringing the silicate solution into contact with the carbonate particles.

• (a) pulvériser une solution aqueuse à base de silicate de métal alcalin ou à base d'un mélange de silicate et de carbonate de métal alcalin sur un lit roulant de particules à base de carbonate de métal alcalin ou à base du mélange identique silicate-carbonate cité ci-dessus défilant dans un dispositif rotatif de granulation, la vitesse de défilement des particules, l'épaisseur du lit roulant et le débit de la solution pulvérisée étant tels que chaque particule se transforme en un cogranulé plastique en entrant en contact avec d'autres particules,
• (b) sécher, éventuellement, lesdits cogranulés obtenus en (a), ces étapes étant mises en oeuvre de telle sorte que le rapport pondéral eau / silicate exprimé en sec reste au moins égal à 33/100.

A preparation process consists of

• (A) spraying an aqueous solution based on alkali metal silicate or based on a mixture of silicate and alkali metal carbonate on a moving bed of particles based on alkali metal carbonate or based on the identical mixture silicate- carbonate cited above passing through a rotary granulation device, the speed of movement of the particles, the thickness of the moving bed and the flow rate of the sprayed solution being such that each particle is transformed into a plastic cogranulate by coming into contact with d '' other particles,
• (b) possibly drying said cogranules obtained in (a), these steps being implemented so that the water / silicate weight ratio expressed as dry remains at least equal to 33/100.

Preferably, between steps (a) and (b), the cogranules are subjected to a densification operation.

Among the alkali metal silicates and carbonates, there may be mentioned in particular those of sodium and potassium, and very particularly those of sodium. By way of example of cogranules based on silicate and carbonate as described above, mention may be made of Nabion® manufactured and marketed by Rhône-Poulenc.

Said cogranules can be used, as alkaline agents reducing visible corrosion of the glass, in amounts such that they represent around 3 to 90%, preferably around 3 to 70% by weight of the said said compositions.

• les agents tensio-actifs en quantité pouvant aller de 0,5 à 10 %, de préférence de l'ordre de 1 à 5 %, du poids de ladite composition exprimé en matière sèche ; parmi ceux-ci on peut citer :
  • . les agents tensio-actifs anioniques du type savons de métaux alcalins (sels alcalins d'acides gras en C₈ - C₂₄), sulfonates alcalins (alcoylbenzène sulfonates en C₈ - C₁₃, alcoylsulfonates en C₁₂ - C₁₆), alcools gras en C₆. C₁₆ oxyéthylénés et sulfatés, alkylphénols en C₈ - C₁₃ oxyéthylénés et sulfatés, les sulfosuccinates alcalins (alcoylsulfosuccinates en C₁₂ - C₁₆)...
  • . les agents tensio-actifs non ioniques du type alcoylphénols en C₆ - C₁₂ polyoxyéthylénés, alcools aliphatiques en C₈ - C₂₂ oxyéthylénés, les copolymères bloc oxyde d'éthylène - oxyde de propylène, les amides carboxyliques éventuellement polyoxyéthylénés...,
  • . les agents tensio-actifs amphotères du type alcoyldiméthyl - bétaïnes
• des "builders" (agents améliorant les propriétés de surface des tensio-actifs) du type :
  • . phosphonates organiques du type de ceux de la gamme DEQUEST® de MONSANTO à raison d'au moins 0,5 % du poids total de formulation exprimé en matière sèche,
  • . phosphates à raison d'au moins 25 % du poids total de formulation exprimé en matière sèche,
  • . acide nitriloacétique jusqu'à environ 10 % du poids total de formulation exprimé en matière sèche,
  • . acide citrique, acide gluconique ou acide tartrique ou leurs sels jusqu'à environ 50 % du poids total de formulation exprimé en matière sèche,
• des agents de blanchiment du type perborates, percarbonates associés ou non au N, N, N', N'-tétraacétyléthylènediamine (TAED) ou des produits chlorés du type des chloroisocyanurates jusqu'à environ 30 % du poids total de ladite composition détergente exprimé en matière sèche,
• des agents anti-incrustation, anti-voile ou anti-tâche du type copolymères d'acide acrylique et d'anhydride maléique ou des homopolymères d'acide acrylique en quantité pouvant aller jusqu'à 10 % environ du poids total de ladite composition détergente exprimé en matière sèche,
• des charges du type sulfate de sodium pour les détergents en poudre en quantité pouvant aller jusqu'à 50 % du poids total de ladite composition exprimé en matière sèche.

Besides the cogranules, alkaline agents reducing visible corrosion of the glass and the decorations, there may be present, in the detergent compositions for washing dishes, the usual additives used in the composition of the detergent formulations for washing in the washing machine. the dishes.
We can cite in particular

• surfactants in an amount which can range from 0.5 to 10%, preferably of the order of 1 to 5%, by weight of said composition expressed as dry matter; among these we can cite:
  • . anionic surfactants such as alkali metal soaps (alkali salts of C ₈ -C ₂₄ fatty acids), alkali sulfonates (C ₈ -C ₁₃ alkylbenzene sulfonates, C ₁₂ -C ₁₆ alkyl sulfonates), fatty alcohols in C ₆ . C ₁₆ oxyethylenated and sulfated, C ₈ alkylphenols - C ₁₃ oxyethylenated and sulfated, alkali sulfosuccinates (C ₁₂ -C ₁₆ alkyl sulfosuccinates) ...
  • . non-ionic surfactants of the polyoxyethylenated C ₆ -C ₁₂ alkylphenols type, oxyethylenated C ₈ -C ₂₂ aliphatic alcohols, ethylene oxide-propylene oxide block copolymers, optionally polyoxyethylenated carboxylic amides, etc.
  • . amphoteric surfactants of the alkyldimethyl - betaines type
• "builders" (agents improving the surface properties of surfactants) of the type:
  • . organic phosphonates of the type of those of the DEQUEST® range of MONSANTO at a rate of at least 0.5% of the total weight of formulation expressed as dry matter,
  • . phosphates at a rate of at least 25% of the total weight of formulation expressed as dry matter,
  • . nitriloacetic acid up to approximately 10% of the total weight of formulation expressed as dry matter,
  • . citric acid, gluconic acid or tartaric acid or their salts up to approximately 50% of the total weight of formulation expressed as dry matter,
• bleaching agents of the perborate type, percarbonates associated or not with N, N, N ', N'-tetraacetylethylenediamine (TAED) or chlorine products of the chloroisocyanurate type up to approximately 30% of the total weight of said detergent composition expressed in dry matter,
• anti-scaling, anti-fogging or anti-staining agents of the acrylic acid and maleic anhydride copolymer type or acrylic acid homopolymers in an amount which can range up to approximately 10% of the total weight of said detergent composition expressed in dry matter,
• fillers of the sodium sulfate type for powdered detergents in an amount which can range up to 50% of the total weight of said composition expressed as dry matter.

The following examples are given by way of illustration.

Example 1 GLASS CORROSION TEST

• Si : 21-43% en poids
• Ca : 2,8-5,8% en poids
• Mg : 1,6-3,4% en poids
• Na: 6,8-14,2% en poids
• Al : 0,3-0,7% en poids

This simplified glass corrosion test reproduces certain washing conditions for dishwasher machines, in particular washing, rinsing and drying cycles. Nature of glass
The glass used is made up of microscopy slides of dimension 2.5 × 7.5 cm, previously cleaned with ethanol, slides whose composition given below is close to that of table glasses.

• If: 21-43% by weight
• Ca: 2.8-5.8% by weight
• Mg: 1.6-3.4% by weight
• Na: 6.8-14.2% by weight
• Al: 0.3-0.7% by weight

Procedure

200 ml of an aqueous washing solution containing 6 g / l of product to be tested are introduced into the container. The container is introduced and kept in an oven at 65 ° C for 1 hour.
In this container, a glass slide is completely immersed in an inclined position. The container is then closed, then placed in an oven at 65 ° C. The blade is taken out of the container every other day, rinsed twice on each side with permuted water using a wash bottle, touched with a finger to remove any film formed, dried in ambient air for 2 hours and plunged back into the washing solution maintained at 65 ° C.
At the end of the test, the slide is weighed after cooling to room temperature and the change in relative mass (in% x 1000) is calculated. The test is repeated another time to confirm the results.
Corrosion visible to the eye is evaluated as follows, relative to a reference blade not subjected to the test.

Assessment of visible corrosion Eye observation

• . de colorisations homogènes d'abord légères puis intenses de la surface, d'une ou de deux couleurs, le passage d'une couleur à l'autre étant continu, sans bords nets
• . à des colorisations hétérogènes d'abord légères puis intenses de la surface, avec présence de plusieurs zones de couleurs différentes, lesdites zones étant délimitées par des bords nets.

The slide to be studied is placed between the eye of the experimenter and a flat black surface, in a room normally lit by daylight facing the experimenter. The blade is placed on the black surface (normal reflection) or slightly inclined near this surface, along an axis parallel to it, in order to intensify the visible surface modifications.
We can thus observe different degrees of iridescence ranging

• . of homogeneous first light then intense colorizations of the surface, of one or two colors, the passage from one color to the other being continuous, without sharp edges
• . to heterogeneous colorizations which are first light then intense on the surface, with the presence of several zones of different colors, said zones being delimited by sharp edges.

Finally, the pH of the solutions is measured at room temperature before immersion of the slide and at the end of the experiment.
This simplified test makes it possible to quickly reproduce the different types of glass corrosion obtained by repeated washing in a dishwasher, the succession of cycles of wash-rinse-dry, under conditions of concentration and temperature close to those used in dishwashers.

• . teneur en carbonate (en poids) = 55%
• . teneur en silicate (en poids) = 29%
• . teneur en eau (en poids) = 16%

comme agents alcalins dans une composition classique de formulation (sans tripolyphosphate de sodium) pour lave-vaisselle donnée au tableau 1.
On réalise le test de corrosion du verre ci-dessus pendant 110 heures.
Les résultats sont donnés au tableau 1 et comparés à ceux obtenus en mettant en oeuvre, comme agent alcalin à la place desdits cogranulés

• . une solution de silicate de sodium de rapport molaire SiO₂ / Na₂O de 2, à 45% de matière active ("silicate liquide R2")
• . ou un mélange d'une poudre de silicate de sodium atomisé de rapport molaire SiO₂ / Na₂O de 2 et de carbonate de sodium léger ("silicate atomisé").

Formulations for dishwashers are prepared by the introduction of cogranules marketed by RHONE-POULENC under the brand NABION® consisting of sodium silicate with an SiO ₂ / Na ₂ O = 2 ratio supported by light sodium carbonate, co-granulated whose general composition is the following :

• . carbonate content (by weight) = 55%
• . silicate content (by weight) = 29%
• . water content (by weight) = 16%

as alkaline agents in a conventional formulation composition (without sodium tripolyphosphate) for dishwashers given in Table 1.
The above glass corrosion test is carried out for 110 hours.
The results are given in Table 1 and compared with those obtained by using, as an alkaline agent in place of said cogranules.

• . a sodium silicate solution with a SiO ₂ / Na ₂ O ₂ molar ratio, 45% of active material ("liquid silicate R2")
• . or a mixture of an atomized sodium silicate powder with a SiO ₂ / Na ₂ O molar ratio of 2 and light sodium carbonate ("atomized silicate").

Table 1 shows that the use of NABION® as an alkaline agent results in a lesser loss in mass of the glass slides, as well as in a homogeneous iridescence of the surface of the glass slides, against a greater and heterogeneous iridescence, with the presence of 4 different colors when using a mixture of carbonate and silicate or silicate alone.

Example 2

• . teneur en carbonate (en poids) = 55%
• . teneur en silicate (en poids) = 29%
• . teneur en eau (en poids) = 16%

comme agents alcalins dans une composition classique de formulation (contenant du tripolyphosphate de sodium) pour lave-vaisselle donnée au tableau 2.
On réalise le test de corrosion du verre ci-dessus pendant 42 heures.
Le tableau 2 montre que l'utilisation de NABION® comme agent alcalin, se traduit par l'absence de corrosion ou par une irisation homogène de la surface des lames de verre, contre une irisation plus importante et hétérogène, avec présence de 3 ou 4 couleurs différentes dans le cas de l'utilisation d'un mélange de carbonate et de silicate.Formulations for dishwashers are prepared by the introduction of cogranules marketed by RHONE-POULENC under the brand NABION® consisting of sodium silicate with an SiO ₂ / Na ₂ O = 2 ratio supported by light sodium carbonate, co-granulated whose general composition is the following :

• . carbonate content (by weight) = 55%
• . silicate content (by weight) = 29%
• . water content (by weight) = 16%

as alkaline agents in a conventional formulation composition (containing sodium tripolyphosphate) for dishwashers given in Table 2.
The above glass corrosion test is carried out for 42 hours.
Table 2 shows that the use of NABION® as an alkaline agent results in the absence of corrosion or in a homogeneous iridescence of the surface of the glass slides, against a greater and heterogeneous iridescence, with the presence of 3 or 4 different colors when using a mixture of carbonate and silicate.

Example 3

• . teneur en carbonate (en poids) = 55%
• . teneur en silicate (en poids) = 29%
• . teneur en eau (en poids) = 16%

comme agents alcalins dans la formulation (sans tripolyphosphate de sodium) pour lave-vaisselle donnée au tableau 3.
On réalise 250 cycles de lavage-rinçage-séchage avec une machine MIELE® automatisée (G 540 Spezial) dans le panier supérieur de laquelle on dispose 4 types différents de verres blancs et 3 types de verres décorés (voir tableau 3).
Le cycle de température choisi est de 65°C ; la dose de détergent utilisée à chaque lavage est de 30g, celle du liquide de rinçage commercial de 2g ; après chaque cycle de lavage-rinçage-séchage, la porte est laissée fermée pendant 10 minutes puis ouverte pendant 30 minutes.
L'évaluation de corrosion se fait visuellement avec une échelle allant de 1 à 10 points, en prenant comme référence les verres à l'état neuf ; les points sont distribués comme suit :

• . 10 points correspondent à un état parfait
• . 9 points correspondent à un endommagement à peine visible (traces blanches sur les verres blancs ou matification du décor du verre)
• . 8 points correspondent à un endommagement visible mais néanmoins acceptable pour le consommateur
• . 6 points correspondent à un blanchiment net du verre blanc ou à un enlèvement net du décor
• . 7 points correspondent à un niveau intermédiaire entre 6 et 8.

A formulation for a dishwasher is prepared by the introduction of cogranules marketed by RHONE-POULENC under the brand NABION® consisting of sodium silicate with a ratio SiO ₂ / Na ₂ O = 2 supported by light sodium carbonate, cogranules whose general composition is the following :

• . carbonate content (by weight) = 55%
• . silicate content (by weight) = 29%
• . water content (by weight) = 16%

as alkaline agents in the formulation (without sodium tripolyphosphate) for dishwashers given in Table 3.
250 washing-rinsing-drying cycles are carried out with an automated MIELE® machine (G 540 Spezial) in the upper basket of which there are 4 different types of white glasses and 3 types of decorated glasses (see table 3).
The temperature cycle chosen is 65 ° C; the dose of detergent used for each wash is 30g, that of the commercial rinsing liquid 2g; after each wash-rinse-dry cycle, the door is left closed for 10 minutes and then opened for 30 minutes.
The corrosion evaluation is done visually with a scale ranging from 1 to 10 points, taking as reference the glasses in new condition; points are distributed as follows:

• . 10 points correspond to a perfect state
• . 9 points correspond to barely visible damage (white marks on the white glasses or matification of the glass decoration)
• . 8 points correspond to visible but nevertheless acceptable damage to the consumer
• . 6 points correspond to a clear whitening of the white glass or a clean removal of the decoration
• . 7 points correspond to an intermediate level between 6 and 8.

The results obtained are given in Table 3.
Table 3 shows that the use of NABION® as an alkaline agent reduces the visible corrosion of glass and glass decorations, for all the glasses tested, by comparison with a mixture of carbonate and silicate.

Example 4 PORCELAIN DECORATION CORROSION TEST

• . teneur en carbonate (en poids) = 55%
• . teneur en silicate (en poids) = 29%
• . teneur en eau (en poids) = 16%

comme agents alcalins dans la formulation (contenant du tripolyphosphate de sodium) pour lave-vaisselle donnée au tableau 4.
On prépare un bain thermostaté à circulation de 20 litres d'eau de dureté 4° TH français portée à 77°C. On y dissout l'équivalent de 2g/l de la formulation détergente. Des assiettes en porcelaine décorée (voir tableau 4) sont ensuite disposées verticalement dans des rails et entièrement plongées dans le bain.
On enchaîne 4 cycles de 16 heures de trempage, avec rinçage intermédiaire entre chaque cycle. Le test dure 64 heures.
L'évaluation de la corrosion se fait visuellement avec une échelle allant de 1 à 5 points, par comparaison avec des assiettes neuves, la valeur de 1 point correspondant à l'état neuf et celle de 5 points correspondant à un enlèvement total des décors. Les résultats obtenus sont donnés au tableau 4.A formulation for a dishwasher is prepared by the introduction of cogranules marketed by RHONE-POULENC under the brand NABION® consisting of sodium silicate with a ratio SiO ₂ / Na ₂ O = 2 supported by light sodium carbonate, cogranules whose general composition is the following :

• . carbonate content (by weight) = 55%
• . silicate content (by weight) = 29%
• . water content (by weight) = 16%

as alkaline agents in the dishwasher formulation (containing sodium tripolyphosphate) given in Table 4.
A thermostatically circulated bath is prepared with 20 liters of water of French 4 ° TH hardness brought to 77 ° C. It dissolves the equivalent of 2g / l of the detergent formulation. Decorated porcelain plates (see Table 4) are then placed vertically in rails and fully immersed in the bath.
There are 4 cycles of 16 hours of soaking, with intermediate rinsing between each cycle. The test lasts 64 hours.
Corrosion is assessed visually with a scale ranging from 1 to 5 points, by comparison with new plates, the value of 1 point corresponding to the new state and that of 5 points corresponding to a total removal of the decorations. The results obtained are given in Table 4.

Table 4 shows that the use of NABION® as an alkaline agent reduces the visible corrosion of plate decorations, for all the types of plates tested, by comparison with a mixture of carbonate and silicate. TABLE 1 Formulation 1 2 3 NABION® such as 30* atomized silicate (expressed in dry) 8.6 liquid silicate R2 (expressed as dry) 8.6 light carbonate (expressed in dry) 16.39 0 sequestering agent based on sodium citrate dihydrate 17 17 17 dispersant based on sodium polyacrylate 6 6 6 non-ionic surfactants 2 2 2 bleaching system (perborate, 1H ₂ O + TAED **) 11 11 11 enzyme 2 2 2 sodium sulfate 30 30 30 water (qs 100) 2 7.01 23.4 initial pH 10.57 10.6 10.18 final pH 10.48 10.39 9.9 mass loss (% x1000) 305.4 363.9 519.8 iridescence nature homogeneous heterogeneous heterogeneous number of different colors 1 4 4 * corresponding to 8.6 parts of silicate (expressed in dry) and 16.39 parts of carbonate (expressed in dry) ** TAED aqueous solution at 92% by weight of tetraacetylene diamine Formulation 1 2 3 4 NABION® such as 54 64 atomized silicate (expressed in dry) 15.12 17.92 sodium tripolyphosphate (expressed in dry) 32.55 32.55 23.25 23.25 light carbonate (expressed in dry) 28.08 33.28 non-ionic surfactants 1 1 1 1 bleaching system (perborate, 1H ₂ O + TAED) 10 10 10 10 sodium sulfate 0 6.54 0 7.75 water (qs 100) 2.45 6.71 1.75 6.8 iridescence nature no visible corrosion heterogeneous homogeneous heterogeneous number of different colors 3 1 4 Formulation 1 2 NABION® such as 50 atomized silicate as is 18 dense carbonate as is 27.5 sequestering agent based on sodium citrate dihydrate 30 30 dispersant based on sodium polyacrylate 5 5 non-ionic surfactants 1 1 bleaching system (perborate, 1H ₂ O + TAED) 10 10 sodium sulfate 4 8.5 visual assessment white glasses crystal glasses 10 8 standard fruit glasses, round 10 8 standard wine balloon glasses 10 8 standard fruit glasses, octagonal 10 8 decor glasses cherry patterns 7 6 apple patterns 7 6 red stripe patterns 7 6 Formulation 1 2 NABION® as is 40 atomized silicate as is 5 light carbonate as is 35 sodium tripolyphosphate as is 30 30 non-ionic surfactants 1.5 1.5 bleaching system (percarbonate + TAED) 7.5 7.5 enzymes (amylase + protease) 1 1 sodium sulfate 20 20 visual assessment fine porcelain with rose decorations ("old country roses") 2.5 4.5 fine porcelain decorated with wild strawberries 1.5 3.5 standard porcelain with green foliage decorations 2 2.5

Claims (3)

Use, as alkaline agents reducing visible corrosion of glass and decorations of glass and porcelain, in detergent compositions in particular for washing in the dishwasher, of co-granules comprising an alkali metal carbonate and an alkali metal siate of formula nSiO ₂ , M ₂ O, formula in which M represents an alkali metal and n is of the order of 1.6 to 3.5, preferably of the order of 1.6 to 2.4, said cogranules having a weight ratio, expressed in dry state, carbonate / silicate of the order of 45/55 to 80/20, preferably of the order of 60/40 to 75/25, with a weight ratio of water / silicate expressed in dry state at least about 33/100, preferably of the order of 40/100 to 120/100. Use according to claim 1), characterized in that said alkali metal silicate or carbonate is a sodium or potassium silicate or carbonate. Use, as alkaline agents reducing visible corrosion of glass and decorations of glass and porcelain, in detergent compositions in particular for washing in a dishwasher, of said co-granules according to claim 1) or 2), in an amount corresponding to 3 to 90%, preferably of the order of 3 to 70% of the weight of said detergent compositions.