EP0633310B1 - Preformulation for detergent composition based on polyimide and a silicate - Google Patents

Description

The present invention relates to a preformulation "buider or" cobuilder " biodegradable for detergent composition, based on a polyimide and silicate mixture.

"Builder" or "cobuilder" means any constituent which improves the performance of surfactants of a detergent composition.

• assurer l'enlèvement des ions indésirables, notamment alcalino-terreux (calcium, magnésium), par séquestration ou précipitation, pour prévenir la précipitation des tensio-actifs anioniques,
• apporter une réserve d'alcalinité et de force ionique,
• maintenir en suspension les salissures extraites,
• empêcher les incrustations minérales du linge observées en cours de lavage.

In general, a "builder" or "cobuilder" can act in multiple ways within the laundry environment. He can :

• ensure the removal of unwanted ions, in particular alkaline earth ions (calcium, magnesium), by sequestration or precipitation, to prevent precipitation of anionic surfactants,
• provide a reserve of alkalinity and ionic strength,
• keep the extracted dirt in suspension,
• prevent mineral deposits from the laundry observed during washing.

For a very long time, tripolyphosphates have been the most frequently used in detergent compositions and detergents. However, they are partly responsible for the eutrophication of the lakes and waters slow flow when not sufficiently eliminated by treatment plants waters ; so we are looking to replace them partially or completely.

Zeolites alone cannot replace tripolyphosphates; they must be reinforced in their action by other additives.

Copolymers of acrylic acid and maleic anhydride (or their alkaline salts or ammonium) have been proposed (EP 25,551) as incrustation inhibitors. They have the disadvantage of not being biodegradable in a natural environment.

To meet the requirements of biodegradability, it has been proposed to use agent title "builder" or "cobuilder" for detergent composition a new range of compounds, peptide polymers and more specifically polymers or amino acid copolymers.

In particular, sodium polyaspartates and polyglutamates, which are useful for their high biodegradability, testify to a good builder or co-builder activity (US 4,428,749). It has been shown to be the negatively charged form of these compounds which is the active form in the detergent formulation.

However, the incorporation of these compounds in their native form in detergent compositions is not satisfactory. After storage compounds are subjected to chemical attack on contact with others constituents of the detergent formulation, such as oxidizing and basic agents, with as a final consequence their degradation.

More recently, it has been proposed to implement a precursor of this new type of "builder" agent, namely their polycondensation product (EP 511 037). Unlike acid derivatives, polyimides have the advantage of being stable in detergent formulations for extended durations.

Unfortunately, these compounds do not prove to be completely satisfactory on an ecological plan, since in themselves they are not themselves biodegradable. In the middle detergent, i.e. in an alkaline aqueous medium, they lead to a species biodegradable but, in neutral medium, they remain in a non-water-soluble form and therefore not biodegradable.

The object of the present invention is precisely to optimize the character biodegradable from this type of compound.

More specifically, a particular formulation has been developed according to the invention of it, such that it simultaneously satisfies the following two imperatives: it remains stable in the detergent formulation and in a humid environment it brought into contact with an aqueous medium of non-alkaline pH in at least one species water-soluble biodegradable and naturally endowed with an activity within the detergent formulation. Optimization of the biodegradable character is not acquired for costs of stability in detergent formulation nor of the subsequent generation of the active species.

By non-alkaline pH is meant in the context of the present invention, a pH unfavorable to the hydrolysis of the polyimide to its water-soluble salts. Are notably covered by this definition the pH of natural aqueous media, such as river water which have values close to neutrality.

More particularly, the subject of the present invention is a "builder" or "cobuilder" preformulation for a detergent composition comprising at least one polyimide polymer mixed with at least one silicate, characterized in that it is capable of generating at least one polypeptide species water-soluble biodegradable when it comes into contact with an aqueous medium of non-alkaline pH and in that the polyimide and the silicate are present therein in a weight ratio polyimide / silicate varying between approximately 40/60 and 55/45.

Unexpectedly, it has been demonstrated that the addition of a silicate to a polyimide and more precisely their intimate mixture leads to a preformulation of behavior which is advantageous in terms of biodegradability. This mixture of the two components is in powder form, in particular in the form of cogranules.
Its behavior can be explained as follows: when this specific pre-formulation of polyimide polymer comes into contact with a high level of humidity, or even encounters a non-alkaline aqueous medium, we witness locally at the level of the grains a lowering of their alkalinity which induces the formation, on the surface of the mixture and more particularly on the surface of the cogranules, of a layer of silica; advantageously, this layer of silica constituting preserves the core of the cogranules containing polyimide and unreacted silicate; in this way, thanks to this "shell" of silica, sufficient alkalinity is generated at the polyimides, generated by the silicates, to make possible the partial or total hydrolysis of said polyimide into its non-contaminating polyamino acid salt or salts. for the environment.

This interesting result is all the more surprising as one might have thought. impractical. Indeed, it would have been possible for the polyimide polymer to immediately lead to its water-soluble salts when it is intimately mixed with silicate, and more particularly when the latter is in the form of an aqueous dispersion concentrated. In this hypothesis we were left with a detergent formulation directly including water-soluble polyimide salts with inherent problems stability discussed above. However, unexpectedly, this is not the case. We get to the result of the intimate mixture of the two components, a paste which, dried, leads to powder in which the polyimide is present in its original form.

By polyimide polymer is meant according to the invention a polyimide biopolymer whose charge density COO ^- is likely to increase in the detergent bath.

By way of example of polyimide biopolymers which can be used, mention may be made of polyimides derived from the polycondensation of aminodiacides, in particular aspartic or glutamic acid or precursors of said aminodiacides; these polymers dissolve in water at basic pH with the formation of COO ^- free functions.

These polymers can be homopolymers derived from racide as well aspartic or glutamic, as copolymers derived from aspartic racide and glutamic acid in any proportions, or copolymers derived from the acid aspartic and / or glutamic and other amino acids (for example up to 15% in weight, preferably less than 5% by weight, of other amino acids).

Among the copolymerizable amino acids, there may be mentioned glycine, alanine, valine, leucine, isoleucine, phenylalanine, methionine, trypotophan, histidine, proline, lysine, arginine, serine, threonine, cysteine ...

Said polyimide biopolymers can have a weight-average molecular mass of the order of 2000 to 10 ⁷ and generally of the order of 3.500 to 60,000.

These, in particular the polyimides derived from aspartic or glutamic acid, can be prepared by thermocondensation of said amino acid (s) in a substantially anhydrous medium, as described in JACS, 80 , 3361 (1958), J. Med. Chem. 16 , 893 (1973), Polymer 23 , 1237 (1982) or in U.S. Patent No. 3,052,655.

Said polyimides preferably have a COO charge density ^- zero; however, they can be partially hydrolyzed (by opening a few imide rings with the formation of alkali or ammonium carboxylates).

Regarding the alkali metal silicates, can be used general those already used as adjuvants in detergency formulation.

However, the most advantageous silicates in this application are those having a SiO ₂ / M ₂ O molar ratio of between 1.6 and 3.5. They are sold either in the form of concentrated solutions at around 30-60% by weight of dry extract, or in the form of silicate powder, atomized and optionally compacted.

Preferably, said silicate has a SiO ₂ / M ₂ O molar ratio of the order of 1.6 to 3.5 and more particularly of the order of 1.8 to 2.6.

Said silicate can be mixed with the polyimide polymer in a form any, structured (powder, granules ...) or not.

According to a preferred embodiment of the invention, it is an aqueous solution at approximately 30-60%, preferably approximately 35-60% by weight of dry extract of a silicate of an alkali metal, in particular of SiO ₂ / M ₂ O ratio of the order of 1.6 to 3.5, preferably of the order of 1.8 to 2.6, preferably with M representing a sodium atom.

According to a particular embodiment of the invention, the preformulation claimed may contain in addition to polyimide and silicate, an alkali metal carbonate. The presence of a carbonate within the preformulation is particularly advantageous in terms of humidity stability.

The carbonate content of said preformulation varies according to the content of silicate. The carbonate percentages presented below will always be expressed relative to the total weight of carbonates and silicates.

Preferably, the carbonate content varies between 20% and 75%, expressed by relative to the total weight of silicates and carbonates.

• une teneur en polymère polyimide de l'ordre de 5% à 35 % en poids de préformulation
• une teneur en silicate de l'ordre de 40 à 60 % en poids en poids de préformulation , pourvu que le rapport pondéral polymère polyimide/silicate soit de 40/60 à 55/45
• une teneur en eau de l'ordre de 10 à 30 % en poids en poids de préformulation
• et le cas échéant une teneur en carbonate de l'ordre de 20 à 30 % en poids telle que définie ci-dessus.

By way of preformulation in accordance with the present invention, mention may in particular be made of those having the following characteristics:

• a polyimide polymer content of the order of 5% to 35% by weight of preformulation
• a silicate content of the order of 40 to 60% by weight by weight of preformulation, provided that the polyimide / silicate polymer weight ratio is from 40/60 to 55/45
• a water content of the order of 10 to 30% by weight by weight of preformulation
• and where appropriate a carbonate content of the order of 20 to 30% by weight as defined above.

• une teneur en polymère polyimide de l'ordre de 35 % en poids,
• une teneur en silicate de l'ordre de 45 % en poids,
• une teneur en eau de l'ordre de 20 %en poids,
• et le cas échéant une teneur en carbonate de l'ordre de 20 à 30 % en poids telle que définie ci-dessus.

By way of preferred preformulation, one can more particularly mention that defined as follows:

• a polyimide polymer content of the order of 35% by weight,
• a silicate content of the order of 45% by weight,
• a water content of the order of 20% by weight,
• and where appropriate a carbonate content of the order of 20 to 30% by weight as defined above.

Said polyimide / silicate mixture with, if appropriate, carbonate can be prepared by bringing into contact (by adsorption and / or absorption) of a concentrated aqueous solution of an alkali metal silicate with a molar ratio SiO ₂ / M ₂ O of 1 '' from 1.6 to 3.5, preferably of the order of 1.8 to 2.6, and having a dry extract of the order of 30 to 60%, preferably of the order of 35 to 60%, with said polyimide polymer and, where appropriate, said carbonate, and drying.

The contacting operation can be carried out by simple addition, or else by spraying said concentrated solution of silicate onto the polyimide throughout known mixer with high shear, in particular of the LODIGE® type, or in the tools for granulation (drum, plate ...), at a temperature of around 20 ° C.

The particles of the mixture obtained can be ground, if desired, so as to obtain an average diameter of the order of 200 to 800 micrometers.

The densified cogranules are then dried by any known means. A method particularly effective is drying in a fluidized bed using an air stream at a temperature of the order of 40 to 150 ° C, preferably 40 to 100 ° C. This operation is carried out for a period depending on the air temperature, the water content of the cogranules at the outlet of the granulation device and that desired dried cogranules, as well as fluidization conditions; the skilled person knows adapt these different conditions to the desired product.

The present invention covers the use of the preformulation for composition detergent claimed in detergent compositions in all proportions. These in fact vary widely depending on the specificity of detergent formulations incorporating it.

By detergent composition is meant generally refer to any detergent formulation, powder or liquid, intended for use both in a washing machine laundry, dishwasher only for household cleaning in general.

In the particular case of compositions for washing machines, the quantities put work can be of the order of 1 to 60%, and preferably of the order of 3 to 40% of the weight of said compositions (these quantities are expressed in preformulation weight relative to the weight of the detergent composition). However, these values are not provided for information only in the context of the present invention and are in no way limiting.

Besides the preformultaion which is the subject of the invention, is present in the detergent composition at least one surfactant in an amount which can range from 8 to 20%, preferably of the order of 10 to 15% of the weight of said composition.

• les agents tensio-actifs anioniques du type savons de métaux alcalins (sels acalins d'acides gras en C₈-C₂₄), sulfonates alcalins (alcoylbenzène sulfonate 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 (alcoysulfosuccinates 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 alcoyldiméthylbétaïnes,
• les agents tensio-actifs cationiques du type chlorures ou bromures d'alkyltriméthylammonium, d'alkyldiméthyléthylammonium.

Among these surfactants, mention may be made of:

• anionic surfactants such as alkali metal soaps (alkaline salts of C ₈ -C ₂₄ fatty acids), alkali sulfonates (C ₈ -C ₁₃ alkylbenzene sulfonate, C ₁₂ -C ₁₆ alkyl sulfonates), fatty alcohols C ₆ -C ₁₆ oxyethylenated and sulfated, C ₈ -C ₁₃ alkylphenols oxyethylenated and sulfated, alkali sulfosuccinates (C ₁₂ -C ₁₆ alkyl sulfosuccinates) ...
• non-ionic surfactants of the C ₆ -C ₁₂ alkylphenol type, polyoxyethylenes, oxyethylenated C ₈ -C ₂₂ aliphatic alcohols, ethylene oxide-propylene oxide block copolymers, optionally polyoxyethylene carboxylic amides,
• amphoteric surfactants of the alkyl dimethyl betaines type,
• cationic surfactants of the chlorides or bromides type of alkyltrimethylammonium, of alkyl dimethylethyl ammonium.

• des agents "builders" annexes du type :
  • phosphates à raison de moins de 25 % du poids total de composition détergente,
  • zéolithes jusqu'à environ 40 % du poids total de composition détergente,
  • carbonate de sodium jusqu'à environ 80 % du poids total de composition détergente,
  • acide nitriloacétique jusqu'à environ 10 % du poids total de composition détergente,
  • acide citrique, acide tartrique jusqu'à environ 20 % du poids total de composition détergente, la quantité totale d'agents "builders" correspondant à environ 0,2 à 80 %, de préférence de 20 à 45 % du poids total de ladite composition détergente,
• des agents de blanchiment du type perborates, percarbonates, chloroisocyanurates, N, N, N',N'-tétra-acétyléthylènediamine (TAED) jusqu'à environ 30 % du poids total de ladite composition détergente,
• des agents anti-redéposition du type carboxyméthylcellulose, méthylcellulose en quantités pouvant aller jusqu'à environ 5 % du poids total de ladite composition détergente,
• des agents anti-incrustation du type copolymères d'acide acrylique et d'anhydride maléïque en quantités pouvant aller jusqu'à 10 % environ du poids total de ladite composition détergente.
• 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 détergente.

Various constituents can also be present in the detergent composition such as:

• additional "builders" agents of the type:
  • phosphates in an amount of less than 25% of the total weight of the detergent composition,
  • zeolites up to about 40% of the total weight of detergent composition,
  • sodium carbonate up to about 80% of the total weight of detergent composition,
  • nitriloacetic acid up to approximately 10% of the total weight of detergent composition,
  • citric acid, tartaric acid up to about 20% of the total weight of detergent composition, the total amount of "builders" agents corresponding to about 0.2 to 80%, preferably 20 to 45% of the total weight of said composition detergent,
• bleaching agents of the perborates, percarbonates, chloroisocyanurates, N, N, N ', N'-tetra-acetylethylenediamine (TAED) type up to approximately 30% of the total weight of said detergent composition,
• anti-redeposition agents of the carboxymethylcellulose, methylcellulose type in amounts which can range up to approximately 5% of the total weight of said detergent composition,
• anti-scaling agents of the acrylic acid and maleic anhydride copolymer type in amounts which can range up to approximately 10% of the total weight of said detergent composition.
• fillers of the sodium sulfate type for powdered detergents in an amount which can range up to 50% of the total weight of said detergent composition.

The following examples are given for information only and cannot be considered as a limit of the scope of the invention.

EXAMPLE 1 Synthesis of a polysuccinimide (PSI) derived from aspartic acid

The equipment is a PARMILLEUX ® dryer made up of two tanks connected by a tube. The first is in an air circulation oven, it has an inlet argon. The second is connected to a vacuum pump.

75 kg of L aspartic acid are introduced into the first tank. We create a slight vacuum under argon circulation in the dryer and the reaction medium is heated to 190/230 ° C for 25 h 30.

After cooling, 54 kg of molecular weight polysuccinimide are recovered. (determined by GPC) Mw = 5290 with a polydispersity index Ip = 1.63. He stays 0.34% water (KARL FISCHER) in the product.

EXAMPLE 2: Preparation of a "builder" A preformulation according to the invention.

A first "builder" A preformulation, according to the invention, was carried out with 150 g of PSI from Example 1 and 320 g of silicate solution with a ratio of 2 to 58% of extract dry, or an excess of silicate. Mixed in a HENRY ® grinder, at temperature ambient, the powder + liquid mixture very quickly becomes a paste then goes through a liquid step before giving a sticky powder. This powder is then passed into a high pressure extruder. The cogranules obtained are dried in a fluidized bed. The composition of the cogranules determined by calcination at 950 ° C for 3 h, is 44% silicate, 35% PSI and 21% water.

EXAMPLE 3: Preparation of a "builder" B preformulation according to the invention.

A second "builder" B preformulation was prepared, according to the operating mode described in example 2, starting from 50 g of PSI of example 1 and 114.8 g of solution of silicate with a ratio of 2 to 54% of dry extract, an excess of silicate. The powder, obtained at the outcome of the reaction is dried overnight in air and then ground in a HENRY® mill. After sieving, the section is recovered between 800 and 200 μm. The composition of cogranules determined by calcination is: 34% PSI; 43% dry silicate; 23 % water. Chemical analysis of total carbon and silica gives: 35% PSI; 41% dry silicate; 24% water.

EXAMPLE 4: Preparation of a "builder" C preformulation which is not according to the invention.

A third "builder" C preformulation was prepared with 105 g of carbonate sodium, 233.5 g sodium silicate solution 45% dry extract and 290 g PSI of example 1. The carbonate and the PSI are stirred for 5 minutes in a mixer LODIGE®. The silicate is added in small nets and the mixing is continued until obtaining a moist and homogeneous powder. The product is dried in a cold fluid bed first then at 60/70 ° C. The carbonates / carbonates + silicates ratio is 1/2.

The washing performance of the preformulations prepared according to the examples precedents were appreciated after incorporation of each of these preformulations in the composition of the washing powder shown in table I.

By way of comparison, the examples presented below also give an account of the performance of three control detergents, one without any builder agent, the second incorporating SOKALAN CP5 and the third of sodium polyaspartate PAsp Na (prepared by basic hydrolysis of polysuccinimide described in example 1). LAUNDRY COMPOSITION BUILDER TEST AGENT White SOKALAN CP5 PAsp Na Builder A Builder B Alkylbenzene sulfonate 7.50% 7.50% 7.50% 7.50% 7.50% RHODASURF LA 90 4% 4% 4% 4% 4% 4 A zeolite 24% 24% 24% 24% 24% Na silicate 1.50% 1.50% 1.50% 1.50% 1.50% Na carbonate 10% 10% 10% 10% 10% TAED 2% 2% 2% 2% 2% Na perborate 15% 15% 15% 15% 15% EDTA 0.10% 0.10% 0.10% 0.10% 0.10% agent builder tested 0 3% Sokalan CP5 3% PAsp Na 6% builder A 8.5% builder B TINOPAL DMSX 0.10% 0.10% 0.10% 0.10% 0.10% TINOPAL SOP 0.10% 0.10% 0.10% 0.10% 0.10% silicone defoamer 0.20% 0.20% 0.20% 0.20% 0.20% alkalaz 0.15% 0.15% 0.15% 0.15% 0.15% savinaz 0.15% 0.15% 0.15% 0.15% 0.15% Na sulfate qs 100% qs 100% qs 100% qs 100% qs 100%

EXAMPLE 5: Determination of anti-encrustation activity of "builders" A and B

The inlay is evaluated by washing reference textiles in the washing machine: cotton testfabric 405 and cotton / polyamide krefeld 12A. After 20 wash cycles at 75 ° C followed by drying, the different samples are burned at 950 ° C for 3 hours, the mineral inlay is calculated from the ash rate expressed in relation to that obtained without additive.

To assess the stability over time of the anti-encrustation activity of the tested builders, the tests were carried out in two stages, from the formulation of the washing powder and after storage thereof for 1 month at 40 ° C. RESULTS BEFORE STORAGE cotton 405 cotton / polyamide 12A White 100% 100% builder A 53% 65% AFTER STORAGE (40 ° C) cotton 405 12A polyamide cotton Na polyaspartate (1 month) 100% 100% builder B (1 month) 46% 42% builder B (2 months) 59% 69%

After storage for 1 month at 40 ° C, the sodium polyaspartate loses all activity then that builder B remains effective after 2 months.

EXAMPLE 6 Moisture stability

To simulate different treatments that raw materials can undergo for detergency, the products are stored at 56% and 90% relative humidity at 20 ° C. A visual observation is made. It consists in assessing the degree of caking of the washing powder after storage. For tests carried out with a humidity rate of 56%, the degree of caking is assessed according to the flowability of the powder and for those carried out with a humidity rate of 90%, it is the humidity degree of this powder which serves as a reference. MOTTAGE NUMBER OF STORAGE DAYS RELATIVE HUMIDITY RATE% 90% 56% PAsp Na builder A CP5 PAsp Na builder A CP5 1 Dry powder Dry powder sticky appearance flows well flows well flows well 2 Wet powder " Sticky " " " 3 " " " " " does not flow

Note that builder A is less sensitive to humidity than CP5 or sodium polyaspartate. It is very good under 56% relative humidity and remains better than the other two at 90% relative humidity.

EXAMPLE 7 Biodegradability

Builder B "ultimate" biodegradability is measured according to AFNOR T90-312 (in accordance with international standard ISO 7827)

• d'un inoculum obtenu par filtration d'eau d'entrée de la station d'épuration urbaine de Saint-Germain au Mont d'Or (Rhône).
• d'un milieu d'essai contenant 4 X 10⁷ bacteries/ml
• d'une quantité de produit à tester telle que le milieu d'essai contienne une concentration en carbone organique de l'ordre de 40 mg/l.

Le taux de biodégradabilité du produit testé est de 45 % en 28 jours.The test is carried out from:

• an inoculum obtained by filtration of inlet water from the Saint-Germain urban wastewater treatment plant at Mont d'Or (Rhône).
• a test medium containing 4 × 10 ⁷ bacteria / ml
• an amount of product to be tested such that the test medium contains a concentration of organic carbon of the order of 40 mg / l.

The biodegradability rate of the tested product is 45% in 28 days.

Claims (15)

1. "Builder" or "cobuilder" preformulation in pulverulent form for detergent compositions, comprising at least one polyimide polymer mixed with at least one silicate, characterized in that it is capable of generating at least one biodegradable water-soluble polypeptide species when it comes into contact with an aqueous medium of non-alkaline pH and in that the polyimide and the silicate are present therein in a polyimide/silicate ratio by weight varying between 40/60 and 55/45.
2. Preformulation according to claim 1, characterized in that the said polyimide biopolymer can be derived from the polycondensation of amino diacids or of the precursers of the said amino diacids.
3. Preformulation according to claim 1 or 2, characterized in that the said polyimide biopolymer can be derived from the polycondensation of aspartic acid and/or of glutamic acid or of the precursers of the said acid(s).
4. Preformulation according to any one of the preceding claims, characterized in that the said polyimide biopolymer has a weight-average molecular mass of the order of 2,000 to 10⁷.
5. Preformulation according to any one of the preceding claims, characterized in that the said polyimide biopolymer has a weight-average molecular mass of the order of 3,500 to 60,000.
6. Preformulation according to any one of the preceding claims, characterized in that the silicate has an SiO₂/M₂O molar ratio of between 1.6 and 3.5, preferably of the order of 1.8 to 2.6.
7. Preformulation according to any one of the preceding claims, characterized in that it can be obtained from an alkali metal, especially sodium or potassium, silicate solution with an SiO₂/M₂O molar ratio of between 1.6 and 3.5, preferably of the order of 1.8 to 2.6, comprising from 30% to 60%, preferably from 35 to 60%, by weight of solids, by bringing the said solution into contact with the said polyimide polymer and drying.
8. Preformulation according to any one of the preceding claims, characterized in that it additionally comprises an alkali metal carbonate.
9. Preformulation according to the preceding claim, characterized in that the carbonate is present in a ratio by weight of the order of 20 to 75% expressed with respect to the total weight of silicates and carbonates.
10. Preformulation according to claim 8 or 9, characterized in that it can be obtained from an alkali metal, especially sodium or potassium, silicate solution with an SiO₂/M₂O molar ratio of between 1.6 and 3.5, preferably of the order of 1.8 to 2.6, comprising from 30% to 60%, preferably from 35 to 60%, by weight of solids, by bringing the said solution into contact with the said polyimide polymer and the said carbonate and drying.
11. Preformulation according to any one of claims 1 to 7, characterized in that it has the following characteristics:

    a polyimide polymer content of the order of 5 to 35% by weight,

    a silicate content of the order of 40 to 60% by weight,

    a water content of 10 to 30% by weight.
12. Preformulation according to claim 11, characterized in that it has the following characteristics:

    a polyimide polymer content of the order of 35% by weight,

    a silicate content of the order of 45% by weight,

    a water content of 20% by weight.
13. Preformulation according to claim 11 or 12, characterized in that it additionally comprises a carbonate content of the order of 20 to 30% by weight expressed with respect to the total weight of silicates and carbonates.
14. Preformulation according to any one of the preceding claims, characterized in that it is provided in the form of cogranulates.
15. Use of the preformulation forming the subject of any one of the preceding claims in a detergent composition.