IE920823A1 - "Builder" agent based on alkali metal silicates for detergent compositions - Google Patents

Abstract

The structureforming agent is designed for powder detergentsubstances applicable is washing lines and dishwasing machines. Itis formed by a silicate of a silicon-rich alkaline metal, in theform of Q2 and Q3. The solution of the alkaline metal silicate inratio between SiO2 to M2O of 1.0 to 3.5 is produced with drymatter form 10 to 80% or in a form for application, especially inthe form of cogranulates. The weight ratio between the silicate inthe form of dry matter and water bound to it is from 100:120 to100:40.28 claims

Description

BUILDER AGENT BASED ON ALKALI METAL SILICATES FOR DETERGENT COMPOSITIONS The present invention relates to a builder agent consisting of alkali metal silicates rich in species in which the silicon atoms are in Q2 and Q3 form, intended for detergent compositions, in particular for pulverulent detergents, especially for a washing machine or for a dishwashing machine.

Builder is understood to be any active 10 adjuvant which improves the performance of the surfaceactive agents in a detergent composition.

It is necessary that the builder has an effect known as softening" on the water used for washing. It is therefore necessary to remove the calcium and the magnesium which are present in the water in the form of soluble salts, and in the soiling on the laundry in complex forms which are soluble to a greater or lesser extent. The removal of the calcium and of the magnesium may be effected either by complexation, in the form of soluble species, or by ion exchange, or by precipitation. In the case of precipitation, this must be controlled in order to prevent deposits on the laundry or on the elements of washing machines.

This precipitation control is obtained in particular by means of water-soluble polymers having an affinity for calcium and magnesium.

It is also necessary that the builder adds, to the emulsifying effect of the surfactants with respect to fatty soiling, a dispersing effect with respect to pigment soiling, such as metal oxides, clays, silica, various dusts, humus, limescale, soot, and the like.

This dispersing effect is generally obtained owing to the presence of polyanions, supplying a high density of negative charges at the interfaces.

It is also necessary that the builder supplies an ionic strength favourable for the operation of the surfactants, in particular by increasing the size of the micelles.

It is also necessary that it supplies OH' ions, for the saponification of fats and also in order to increase the negative surface charges at textile surfaces and particulate soil.

Silicates have long been regarded as good detergent adjuvants, but are currently less used in phosphate-free compositions for washing machines.

The silicates most widely used in this application are those having a molar ratio of SiO2/Na2O of between 1.6 and 2.4. They are marketed either in the z \ form of concentrated solutions having a solids content of 35-45% by weight approximately or in the form of pulverised and optionally compacted silicate powder.

The concentrated commercial solutions are most frequently prepared from completely amorphous silicate which is known as vitreous and is also termed soluble glass.

These soluble glasses are rendered watersoluble in an autoclave under pressure at 140°C.

Commercial solutions having a dry solids content of % by weight approximately for a silicate of ratio 2 and 35% approximately for a silicate of ratio 3.5 are obtained in this way.

The concentrated silicate solutions are 10 introduced by the detergent-formulating company into the aqueous suspension (slurry) containing the other constituents of the detergent. The slurry is then dried by spraying. The silicate, which is co-sprayed and codried with the other constituents, then contains no more than 20% of associated water, with respect to its dry weight, or even less.

With regard to the commercial silicate powder, this is obtained by spray-drying concentrated solutions of vitreous silicate; it is necessary to retain 20 to 22% by weight of water with respect to the finished product in order to ensure good solubility of the said product.

It has been found that when it is dissolved in a washing bath in a proportion of 1 to 3 g/litre, this silicate powder, which contains only 20 to 22% by weight of associated water (with respect to the finished product), has only weak builder properties.

In fact, this dissolved silicate powder essentially gives rise to monomeric silicon-containing species of formula Si(OX)4, where X represents H or Na, which do not have a builder effect. Such monomeric species are able to recombine with one another to form polyanions only if the silicate concentration is at least 50 to 500 g/litre, and do so slowly.

Such silicate concentrations and the slow polymerisation kinetics of the monomeric species are not compatible with the washing conditions and washing times in a washing machine.

The findings in respect of a powder containing from 20 to 22% of chemically bonded water (with respect to the finished product) are, of course, valid for the formulations containing a silicate containing 20% of associated water (with respect to the dry silicate) prepared by introduction of a concentrated silicate solution into a slurry and then drying.

The Applicant has found that when an alkali metal silicate is rich in species in which the silicon atoms are in Q2 and Q3 form, the polyanionic species formed by dilution to 1 to 3 g/1 in a detergent medium have a lifetime sufficient to enable them to act as detergent builder.

The term silicon atoms in Qz and Q3 form is a representation of the degree of association of the silicon atoms with one another? Q2 signifies that each silicon atom participates in two -Si-O-Si- bonds, the two remaining bonds being a terminal -Si-O-X, where X is an alkali metal or H; Q3 signifies that each silicon atom participates in three -Si-O-Si- bonds, the remaining bond being a terminal -Si-O-X.

The builder agent for a detergent composition which is the subject of the invention is characterised in that it consists of an alkali metal silicate, in particular sodium silicate or potassium silicate, containing at least 30% and preferably at least 50% of silicon atoms in Q2 and Q3 form.

The said silicate may have a SiO2/M2O molar ratio of the order of 1.6 to 3.5, preferably of the order of 1.8 to 2.6.

The said builder agent may be in any form 15 and may or may not have a structure (powder, granules, and the like).

A first embodiment of the invention is a builder agent consisting of an aqueous solution containing about 10-60%, preferably about 35-50%, by weight of solids of an alkali metal silicate, in particular sodium silicate or potassium silicate, having a SiO2/M2O molar ratio of the order of 1.6 to 3.5, preferably of the order of 1.8 to 2.6.

The concentrated alkali metal silicate solution used as builder agent is preferably obtained by rendering soluble glasses water-soluble in an autoclave under pressure at 140®C, followed by dilution if necessary; it may also be obtained by other known means, such as direct attack by concentrated caustic soda solution on sand.

It is found by NMR analysis that: - a solution having a 45% solids content of vitreous silicate having a SiO2/Na2O molar ratio of 2 contains 34% of Q3 species, 51% of Q2 species, 12% of Qx species and 3% of Qo species, and - a solution having a 35% solids content and a ratio of 3.5 contains 46% of Q3 species, 27% of Q2 species, 16% of Q<, species, 9% of Qx species and 2% of Qo species.

The said builder solution may be used in post-addition by spraying onto the detergent powder at the bottom of the tower in the case of a spray installation, or onto the mixture of the components of the detergent formulation in the case of a dry mixture, said spraying being within the limit of the adsorbent power of the powders. The pulverulent mixture obtained may be moderately dried if necessary, such that the ratio by weight of dry silicate/water remaining associated with the silicate is between 100/120 and 100/40, preferably between 100/90 and 100/50.

The amount of silicate solution which may be used is such that the ratio by weight of dry silicate/detergent powder is between 1/100 and 30/100, preferably of the order of 10/100 to 20/100.

Another nonlimiting embodiment of the invention comprises an aqueous solution containing about 10-60%, preferably about 35-50%, by weight of solids of an alkali metal silicate, in particular sodium silicate or potassium silicate, having a SiO2/M2O molar ratio of the order of 1.6 to 3.5, preferably of the order of 1.8 to 2.6, adsorbed and/or absorbed on a particulate support which is inert with respect to the silicate, the ratio by weight of silicate expressed on dry basis/water remaining associated with the silicate ranging from 100/120 to 100/40, preferably ranging from 100/90 to 100/50.

Inert signifies chemically inert.

Water associated with the silicate is understood to be the water in the supported solution which is not combined with the inorganic support, in particular in the form of crystalline hydrate.

Amongst the inorganic supports for the silicate solution, compounds which may be mentioned are preferably water-soluble compounds such as: sodium carbonate, sodium sulphate, sodium borate, sodium perborate, sodium metasilicate and phosphates or polyphosphates, such as trisodium phosphate, sodium tripolyphosphate, and the like, these supports being present on their own or as a mixture with one another.

The support generally represents of the order of 55 to 95%, preferably of the order of 65 to 85%, of the weight of the supported solution, expressed as solids (that is to say weight of solution expressed as solids + weight of support).

The said supported solution may be prepared by adsorption and/or absorption by bringing a concentrated aqueous solution of an alkali metal silicate having a SiO2/M2O molar ratio of the order of 1.6 to 3.5, preferably of the order of 1.8 to 2.6, and having a solids content of the order of 10 to 60%, preferably of the order of 35 to 50%, into contact with an inorganic support which is inert with respect to the silicate, the said support being present in an amount such that the amount of water remaining associated with the said silicate after adsorption and/or absorption corresponds to a ratio by weight of silicate expressed on dry basis/water associated with the silicate of the order of 100/120 to 100/40, preferably of the order of 100/90 to 100/50.

The operation for bringing into contact may be effected by addition, in particular by spraying, of the said concentrated silicate solution onto the support in particulate form, in any known high-shear mixer, in particular of the Lodige* type, or in granulating equipment (drum, plate and the like) and the like, at a temperature of the order of 20 to 95°C, preferably of the order of 70 to 95°C.

The supports which may be used are those already mentioned in the above list.

The amount and the concentration of the silicate solution to be used depend on the absorbent and/or adsorbent power of the support, taking into account any possibility for the said support to form, in particular, crystallisable hydrates; the water fraction not associated with the silicate, which may be in hydrate form in the support, may be determined in a known manner by differential thermal analysis or by quantitative X-ray diffraction. Any water combined with the support in forms other than defined hydrates may be determined by suitable physicochemical methods (thermoporosimetry, thermogravimetric analysis, proton NMR, IR).

The limit of the adsorbent and/or absorbent power of the said support may be determined by known methods, for example by measuring the change in the angle at the base of the natural slope as a function of the proportion in which the silicate solution is added.

If necessary, the mixture consisting of the support and the silicate solution may itself be dried, but moderately so as to obtain the desired proportions of water associated with the silicate.

The particles of supported silicate solution obtained may be ground, if desired, so as to obtain an average diameter of the order of 200 to 800 micrometers.

Alkali metal silicate solutions in adsorbed and/or absorbed form on an alkali metal carbonate which are in the form of spherical cogranules of hydrated alkali metal silicate and alkali metal carbonate are builder agents of the invention which give a very particularly good performance.

The said spherical cogranules of hydrated alkali metal silicates and alkali metal carbonates may be prepared by a process characterised in that: - an aqueous solution based on alkali metal silicates or based on a mixture of alkali metal silicates and alkali metal carbonates is sprayed onto a rolling bed of particles based on alkali metal carbonates travelling in a rotary granulating device, the speed of travel of the particles, the thickness of the rolling bed and the flow rate of the sprayed solution being such that each particle is converted into a plastic cogranule on coming into contact with other particles, - the cogranules obtained are subjected to a densification operation, and - the said densified cogranules are dried until a content of water associated with the silicate corresponding to a ratio by weight of silicate expressed on dry basis/water associated with the silicate of the order of 100/120 to 100/40 is obtained.

Amongst the alkali metal silicates and alkali metal carbonates, those which may preferably be mentioned are sodium silicate and carbonate and potassium silicate and carbonate, and very particularly sodium silicate and carbonate.

The sprayed aqueous solution based on silicate or silicate/carbonate mixture may have a solids content of the order of 30 to 55% by weight, preferably of 30 to 45% by weight; the said alkali metal silicate has a SiO2/M2O molar ratio of the order of 1.6 to 3.5, preferably of the order of 1.8 to 2.6 and very particularly close to 2; the said carbonate may optionally be present in proportions depending on the desired end product.

Spraying of the solution based on silicate or silicate/carbonate mixture is carried out at a temperature of the order of 20 to 95°C, preferably of the order of 70 to 95eC; spraying may be promoted by the conjoint introduction (for example using a twofluid nozzle) of air under pressure at a temperature of the same order.

The particles used to prepare the cogranules mainly consist of alkali metal carbonate having: - an average diameter of the order of 10 to 150 microns, preferably of the order of 20 to 100 microns and very particularly close to 30 to 80 microns, - an unsettled packing density (non-bulk density) of the order of 0.4 to 1.1 g/cm3, preferably of the order of 0.6 to 1.1 g/cm3, - a water content of the order of 0.05 to 0.4%, preferably of the order of 0.1 to 0.3% by weight, and - a proportion of insoluble matter of the order of 5 to 100 mg/kg, generally of the order of 10 to 60 mg/kg.

Common ground or nonground grades of carbonate may be used.

Alongside these carbonate particles, small 5 amounts (less than 10% of the weight of the cogranules) of other particles may be present, such as antiredepositing polymers (carboxymethyl cellulose and the like), enzymes and the like, commonly used in the detergent field and having a diameter and a density close to those of the carbonate particles.

The device used to carry out the cogranulation operation by means of spraying may be any rotary device of the rotating plate, rotating dish or drum or mixer/granulator type, and the like.

A first preferred method for the production of these cogranules consists in using a rotary granulator permitting movement of the particles as a thin layer. Dishes having an axis of rotation inclined to the horizontal at an angle of more than 20°, preferably more than 40°, are particularly suitable; their geometry may be very diverse: truncated cone, flat, stepped, a combination of these three shapes, and the like.

A second preferred method for the production of these cogranules consists in using a rotary drum, the angle of inclination of which is at least 3% and preferably at least 5%.

The carbonate-based particles travel at a temperature of the order of 15 to 200°C, preferably of the order of 15 to 120‘C and very particularly of the order of 15 to 30°C.

The amounts of solution based on silicate or 5 silicate/carbonate mixture to be sprayed and of carbonate-based particles to be used correspond to a liquid flow rate/particle flow rate ratio which can range from 0.2 to 0.8 1/kg, preferably from 0.4 to 0.7 1/kg and very particularly from 0.62 to 0.7 1/kg, these values being expressed as sodium salts.

The flow rate of the sprayed solution, the speed at which the particles travel and the thickness of the layer of travelling particles are such that each particle absorbs liquid and agglomerates with other particles with which it comes into contact, in order to obtain plastic granules and not a paste.

The speed at which the particles travel and the thickness of the layer are controlled by the flow rate at which the particles are introduced into the granulating device and by the characteristics of the latter.

The residence time of the particles in a device of the plate or drum type is generally of the order of 15 to 40 minutes.

It is within the scope of those skilled in the art to adapt the characteristics of the equipment used to the desired product depending on a given starting material; that is to say, for a dish: its geometry (truncated cone, flat, stepped or a combination of the three shapes), its dimensions (depth, diameter), its angle of inclination, its speed of rotation, and the relative positions of the solid and liquid feeds.

For a drum: its geometry (tube diameter), its angle of inclination, its speed of rotation, the tube charge, and the relative positions of the solid and liquid feeds.

The undensified and undried cogranules obtained have characteristics which depend on the conditions used to effect granulation. They generally have: - a silicate content of the order of 7 to 30% by weight, preferably of the order of 11 to 23% by weight, and very particularly of the order of 21 to 23% by weight, - a carbonate content of the order of 41 to 75% by weight, preferably of the order of 48 to 64% by weight and very particularly of the order of 48 to 51% by weight, and - a water content of the order of 18 to 29%, preferably of the order of 25 to 29%, by weight, and very particularly of the order of 27 to 29% by weight.

The densification operation may be carried out at ambient temperature by rolling the cogranules obtained in the granulation step in a rotary device.

This device is preferably independent of the granulating device.

This densification step may advantageously be carried out by introduction and residence of the cogranules in a rotary drum. The angle of inclination of the latter is at least 3%, preferably at least 5%.

The dimensions of this drum, its speed of rotation and the residence time of the cogranules depend on the density desired; the residence time is generally of the order of 20 minutes to 3 hours, preferably of the order of 20 to 90 minutes.

Mixer/granulators are also suitable for this densification operation.

The cogranulation and densification operations may also be carried out in the same device, for example in a stepped dish, the densification of the cogranules being obtained by rolling the said cogranules on the final steps of the apparatus; similarly, these two operations may be carried out in a two-section drum.

The densified cogranules are then dried by any known means. A particularly highly efficient method is drying in a fluidised bed with the aid of a stream of air at a temperature of the order of 40 to 90°C, preferably of 60 to 80°C. This operation is carried out for a period which depends on the temperature of the air, the water content of the cogranules at the outlet of the granulation device and that desired for the dried cogranules, as well as on the fluidisation conditions; those skilled in the art know how to adapt these various conditions to the desired product.

The dried dense cogranules generally have: - a silicate content of the order of 8 to 38% by weight, preferably of the order of 14 to 31% by weight, and very particularly of the order of 24 to 31% by weight, - a carbonate content of the order of 47 to 87% by weight, preferably of the order of 59 to 81% by weight, and very particularly of the order of 64 to 69% by weight, - a water content of the order of 5 to 25% by weight, preferably of the order of 7 to 20% by weight, and very particularly of 12 to 20% by weight, - a non-bulk density of the order of 0.7 to 1.5 g/cm3, preferably of the order of 0.75 to 1.5 g/cm3 and very particularly of the order of 0.8 to 1 g/cm3, and - an median diameter (in the sense of cumulative percentages passing) of the order of 0.4 to 1.8 mm, preferably of the order of 0.6 to 0.8 mm, with a log10 standard deviation of 0.02 to 0.3, preferably of 0.05 to 0.1.

These cogranulation/densification/drying steps make it possible to obtain cogranules which are based on hydrated alkali metal silicates and on alkali metal carbonates and are perfectly spherical, dense and which dissolve rapidly in water.

Spherical cogranules based on hydrated sodium silicates and on sodium carbonate which are particularly suitable for the preparation of detergent compositions for a dishwashing machine and a washing machine are those having the following characteristics: a silicate content of the order of 24 to 31% by weight, a carbonate content of the order of 64 to 69% by weight, - a water content of 12 to 20% by weight, a non-bulk density of the order of 0.7 to 1.5 g/cm3, preferably of the order of 0.8 to 1, a median diameter of the order of 0.4 to 0.8 mm, with a log10 standard deviation of 0.05 to 0.1, and a speed of less than 2 minutes for 90% dissolution in water and of less than 4 minutes for 95% dissolution in water.

Speed for 90% or 95% dissolution in water is understood to be the time necessary to dissolve 90 to 95% of the product at a concentration of 35 g/1 in water at 20°C.

When it has a structure (powder, cogranule, and the like) the builder agent of the invention is used in detergent compositions for dishwashing in an amount of 3 to 90% by weight, preferably of 3 to 70% by weight of the said compositions; the amounts used in the compositions for a washing machine are of the order of 3 to 60%, preferably of the order of 3 to 40% of the weight of the said compositions (these amounts are expressed as weight of dry silicate relative to the weight of the composition).

Alongside the builder agent which is the subject of the invention, the detergent composition contains at least one surfactant in an amount which can range from 8 to 20% and is preferably of the order of to 15% of the weight of the said composition.

Amongst these surfactants, the following may be mentioned: - anionic surfactants of the type comprising alkali metal soaps (alkali metal salts of C8-C24 fatty acids), alkali metal sulphonates (C8-C13 alkylbenzenesulphonates and C12-C18 alkylsulphonates), oxyethylenated and sulphated C6-C16 fatty alcohols, oxyethylenated and sulphated C8-C13 alkylphenols, alkali metal sulphosuccinates (C12-C18 alkylsulphosuccinates) and the like, - nonionic surfactants of the type comprising polyoxyethylenated C6-C12 alkylphenols, oxyethylenated C8-C22 aliphatic alcohols, ethylene oxide/propylene oxide block copolymers and optionally polyoxyethylenated carboxylic amides, - amphoteric surfactants of the alkyldimethylbetaine type, and - cationic surfactants of the type comprising alkyltrimethylammonium chlorides or bromides and alkyldimethylethylammonium chlorides or bromides. Various constituents may also be present in the detergent composition, such as: - builders of the type comprising: phosphates in an amount of at least 25% of the total weight of the formulation, zeolites in an amount of up to about 40% of the total weight of the formulation, - sodium carbonate in an amount of up to about 80% of the total weight of the formulation, nitriloacetic acid in an amount of up to about 10% of the total weight of the formulation, and citric acid or tartaric acid in an amount of up to about 20% of the total weight of the formulation, the total amount of builder corresponding to about 0.2 to 80%, preferably 20 to 45%, of the total weight of the said detergent composition, - bleaching agents of the type comprising perborates, percarbonates, chlorpisocyanurates and Ν,Ν,Ν',N'-tetraacetylethylenediamine (TAED) in an amount of up to 30% of the total weight of the said detergent composition, - anti-redepositing agents of the type comprising carboxymethyl cellulose or methyl cellulose in amounts which can be up to about 5% of the total weight of the said detergent composition, - anti-incrustation agents of the type comprising acrylic acid and maleic anhydride copolymers in an amount which can be up to about 10% of the total weight of the said detergent composition, and - fillers of the sodium sulphate type for pulverulent detergents in an amount which can be up to 50% of the total weight of the said detergent composition.

The following examples are given by way of illustration and may not be regarded as restricting the scope and the spirit of the invention.

EXAMPLES 1 to 5 The builder performance characteristics - of a sodium silicate solution having a SiO2/Na2O molar ratio 2 with 45% by weight of dry solids (Example 2), and - of a sodium silicate solution having a SiO2/Na2O molar ratio » 3.4 with 35% by weight of dry solids (Example 4) are determined in a Tergotometre (US Testing Company, Hoboken, USA), as a binary mixture with a LABS anionic surfactant (linear sodium dodecylbenzenesulphonate from Aldrich), the reflectance measurements being carried out using a Gardner reflectometer.

These performance characteristics are compared with those: - of the LABS on its own in a concentration of 2 g/1 (Example 1), - of a sprayed silicate powder having a ratio of 2 and containing 22% of water (which is 28.2% of water with respect to the dry silicate) (Example 3), and - of a sprayed silicate powder having a ratio of 3.4 and containing 18.6% of water (which is 22.8% of water with respect to the dry silicate) (Example 5) used under the same conditions (4 g/1).

The results of these determinations are given in Table I Method of determination Principle: A simplified machine wash is simulated in a tergotometer by washing standardised test pieces of soiled fabric at 65°C using a surfactant and the builder to be tested. The wash takes 20 minutes and the colour of the fabrics is determined before and after washing. A blank is carried out by washing the same type of test pieces with the surfactant on its own, in order to evaluate the performance of the builder tested.

Method: The tergotometer is an apparatus consisting of 4 stainless steel 2-1 vessels on which pulsators, which are regulated to 100 cycles per minute, are fitted. The vessels are placed in a water tank which is controlled at 65°C. 1) 1 litre of hard tap water (34° French total hardness) is placed in each 10 vessel.

When the water is at temperature, the following are introduced: - 5 10 x 12 cm test pieces of style 405 W white cotton from Test Fabric, - 5 10 x 12 cm test pieces of white polyester cotton (PEC), reference no. 7435, from Test Fabric, - 2 10 x 12 cm test pieces of cotton soiled with EMPA (mixture of Indian ink and olive oil), article 101 from Galien, - 2 10 x 12 cm test pieces of cotton soiled with red wine, article 114 from Galien, and - 2 10 x 12 cm test pieces of polyester cotton (PEC) soiled with EMPA, article 104 from Galien. ✓ \ 2) The following 3 operations are carried out simultaneously: - the stopwatch is started, - agitation is started, and - the builder/surfactant mixture is added.

The builder is tested at 4 g/1 (mass calculated as dry material in the product) and 2 g/1 of LABS are added thereto. 3) Rinsing When twenty minutes have elapsed, the wash water is discarded and the fabrics are rinsed with 3 x 1 1 of cold tap water. 4) Spinning and drying The test pieces are spun and predried by 10 spreading them individually in absorbent paper. The fabrics are then passed twice through a rolling machine between two sheets of absorbent paper at a temperature of about 110°C.

) Colour determination The Gardner apparatus is calibrated by zero measurement on a black plate reserved for this purpose and then by reading the values L, a and b on a standardised white plate of the same type as the black.

L places the colour in the shades from white to black.

L » 100 corresponds to white test piece L * 0 corresponds to black test piece a places the colour in the shades from green to red. a > 0 : the colour tends to red a < 0 : the colour tends to green b places the colour in the shades from yellow to blue. b > 0 : the colour tends to yellow b < 0 : the colour tends to blue After calibration, the determinations proper are carried out. 2 test pieces of each fabric category are taken from each vessel and 5 determinations are carried out per test piece (that is to say one at the centre and one at the four corners), by placing a heavy metal plate on the fabric, and the arithmetic mean of the 10 determinations is then calculated. The same 10 procedure is used with unwashed fabrics. 6) Calculation of the results DL and DE are calculated for each test and for each type of fabric.

DL = L after washing - L before washing 15 Da = a before washing - a after washing Db = b before washing - b after washing DE = DL2 + Da2 + Db2 = detergency The mean DL and DE for each product and each type of soiled fabric are calculated.

Subsequently, the following are calculated for each products Det(ergency) EMPA cotton » mean DE EMPA cotton Det(ergency) EMPA PEC mean DE EMPA PEC Det(ergency) WINE cotton « mean DE WINE cotton Det(ergency) cumulative = sum of the EMPA cotton, EMPA PEC and WINE cotton detergencies EXAMPLES 6 and 7 A Lodige M5G* mixer (marketed by Lodige) is charged with 800 g of H2 anhydrous tripolyphosphate* marketed by Rhone-Poulenc.

After closing the apparatus and switching to rotation at a speed of 400 rev/min, 200 g of a solution of sodium silicate having a SiO2/Na2O molar ratio = 2 and 45% of solids are introduced by spraying.

This addition takes 10 min; after a further 10 10 min of mixing by rotation, the product is removed and is left to stand for 2 h on a plate in the open air and at ambient temperature.

The characteristics of the product are as follows: - partially hydrated TPP: 82% by weight - sodium silicate: 9% by weight - water associated with the silicate: 9% by weight, which is 100% with respect to the dry silicate.

The total amount of water contained in the 20 product is determined by measuring the loss in weight of the latter on heating to 500°C; on the other hand, the amount of water bonded in the form of hydrates is determined by differential thermal analysis. The amount of associated water is calculated from the difference between the total water and water bonded in the form of hydrate. - average diameter « 250 micrometers The builder performance characteristics of this product are determined using the method described above, but replacing the 2 EMPA-soiled PEC, article 104, test pieces by 2 test pieces of cotton soiled with WFK from Krefeld, of the same dimensions (Example 6).

These performance characteristics are compared with those of a mixture of H2 anhydrous TPP* powder and sprayed silicate powder having a SiO2/Na2O ratio = 2 and containing 22% of water, in a weight ratio of TPP/dry silicate of 800/90, the comparison being made under the same conditions (4 g/1) (Example 7).

The results of the determinations are given in Table II.

EXAMPLE 8 The granulating system comprises a flat plate 800 mm in diameter and 100 mm deep. During granulation, the speed of rotation is of the order of 35 rev/min and the inclination of the axis of rotation relative to the horizontal is of the order of 55°. The granulating plate is fed continuously at a flow rate of 21.4 kg/h with a powder consisting of fine particles of sodium carbonate, the main characteristics of which are as follows: - alkalinity titre: 99.61% - water content (by weight) = 0.12% - non-bulk density - 0.56g/cm3 I - median diameter = 95 microns - insoluble matter content = 58 mg/kg With the aid of air at 80°C, a solution of sodium silicate is sprayed at a flow rate of 13.4 1/h at a temperature of 80°C onto this powder, which is rotated in the granulating dish, via a two-fluid nozzle located at a distance of 20 cm from the bottom of the dish. The proportion of active material and the Si02/Na20 molar ratio of the sprayed solution are, respectively, 43% (by weight) and 2.

The average residence time of a particle in the plate is about 10 to 15 min. The temperature of the particles on leaving the plate is the ambient temperature.

The granules which leave the plate are introduced into a smooth-walled rotary tube 500 mm in diameter and 1300 mm long which has an inclination of the order of 5%. The outlet diaphragm is adjusted so that the average residence time of a particle is about 40 min. The speed of rotation of the drum (18 rev/min) is chosen so as to have a rolling bed of particles, which promotes the densification of the latter.

The granules thus obtained are dried in a fluidised bed at a temperature of the order of 80eC (the temperature of the fluidising air is 85-90°C) for to 15 min.

The product dried in this way has the following characteristics : - carbonate content (by weight) = 65% - silicate content (by weight) = 21% ± 0.5% - water content (by weight) 13.5% - non-bulk density = 0.90 g/cm3 - % by weight oversize at 1 mm = 10.8% - median diameter = 0.73 mm - % by weight passing at 0.2 mm 6% - 90% (by weight) of the product dissolves in 50 s (35 g/1 aqueous solution at 20eC), - 95% (by weight) of the product dissolves in 65 s (35 g/1 aqueous solution at 20eC), - whiteness L » 96.3 - abrasion resistance: 7%.

The granules have excellent stability on storage.

Determination of the abrasion resistance: Equipment: A flourometer, a standardised apparatus used to qualify hydraulic binders and described in French Standard P 15-443, is used.

Method: Sieve 50 g of product between 1200 and 180 micron sieves using a Roto-Lab* laboratory sieve apparatus (marketed by Prolabo).

Recover the fraction between 180 and 1200 microns.

Accurately weigh about 25 g of the product to be tested; let this be M the precise weight.

Place the latter in the flourometer.

Weigh an empty and dry Soxhlet*-type filter (marketed by Prolabo) and place it on the upper part of the fluidisation tube; let its mass be Ml.

Fluidize for 5 min (flow rate of dry air: 1/min).

Recover the product which has flown into the filter and any fines deposited on the vertical walls of the fluidisation tube, using a scraper of suitable diameter. Weigh; let this be M2, the mass of these fines and of the filter.

Resieve the residue in the bottom of the fluidisation tube in the Roto-Lab* and recover, for weighing, the fines smaller than 180 microns; let this be M3, the mass of these fines.

Calculation Expression of the result: The degree of abrasion is equal to the percentage of fines < 180 microns formed during the time for which the product is fluidised.

Abrasion % = (M3 + M2 - MU x 100 M EXAMPLE 9: The operations described in Example 1 are repeated making the following modifications only: Granulation; - granulating plate ; speed of rotation of 30 rev/min, - powder feed : 22 kg/h, and - silicate solution feed ; 13 1/h.

Densification: - speed of rotation of the drum ; 10 rev/min.

Drying in the fluidised bed: - temperature 90°C, - time ; 20 min.

The dried product has the following 20 characteristics: - carbonate content (by weight) · 60.9%, - silicate content (by weight) 22.9% ± 0.5%, - water content (by weight) 16.1% - non-bulk density 0.86 g/cm3 - % by weight over size at 1 mm 2.6% - median diameter « 0.64 mm - % by weight passing at 0.2 mm » 7.3% - 90% (by weight) of the product dissolves in 75 s (35 g/1 aqueous solution at 20°C), - 95% (by weight) of the product dissolves in 102 s (35 g/1 aqueous solution at 20°C), - whiteness L = 95.6, and - abrasion resistance : 9.2% The granules have excellent stability on storage.

EXAMPLE 10; The granulating system comprises a smoothwalled drum rotating at 40 rev/min, 500 mm in diameter and 1300 mm long, having an inclination of the order of 7.5%. The outlet diaphragm is adjusted such that the average residence time of a particle is of the order of to 20 min.

The drum is fed continuously at a flow rate of 37 kg/h with a carbonate powder having the same characteristics as those of the powder of Examples 1 and 2 .

With the aid of air at 80°C, a silicate solution (containing a proportion of active material of 45.6% by weight and having a weight ratio of SiO2/Na2O of 2) is sprayed at 80eC with a flow rate of 18 1/h onto this powder, which is rotated in the drum, via a flat-jet two-fluid nozzle located in the first third of the drum.

The cogranules at the outlet of the drum are at ambient temperature and have a density of 0.68 g/cm3, The cogranules are then densified discontinuously for one hour in a smooth-walled rotary drum 500 mm in diameter and 1300 mm long, having an inclination of 5%.

The speed of rotation of the drum is rev/min.

The granules thus obtained are dried in a fluidised bed at a temperature of the order of 65°C (the temperature of the fluidising air is 70°C) for min.

The dried product has the following characteristics: - carbonate content (by weight) = 62%, - silicate content (by weight) = 20.5% ± 0.5%, - water content (by weight) = 17.6%, - non-bulk density = 0.820 - % by weight over size at 1 mm = 5%, - median diameter « 0.65 mm % by weight passing at 0.2 mm = 0.6% - 90% (by weight) of the product dissolves in 50 s (35 g/i aqueous solution at 20®C), - 95% (by weight) of the product dissolves in 63 s (35 g/i aqueous solution at 20®C).

The granules have excellent stability on storage. 25 EXAMPLE 11; The operations described in Example 3 are repeated, making the following modification only: Densification: - discontinuous for 2 hours.

The dried product has the following characteristics: - carbonate content (by weight) = 60.8%, - silicate content (by weight) = 19.3% ± 0.5%, - water content (by weight) = 19.9%, - non-bulk density * 0.91 g/cm3, - % by weight over size at 1 mm = 1.6%, - median diameter = 0.57 mm - % by weight passing at 0.2 mm = 1.22%, - 90% (by weight) of the product dissolves in 37 s (35 g/1 aqueous solution at 20eC), and - 95% (by weight) of the product dissolves in 45 s (35 g/1 aqueous solution at 20eC).

The granules have excellent stability on storage.

EXAMPLES 12 and 13 The builder performance characteristics of the cogranules of Example 8 are determined by the method described in Examples 1 to 5.

They are compared with those of a mixture of sodium carbonate powder and sprayed sodium silicate powder having a SiO2/Na2O ratio » 2 and containing 22% of water in the finished product (which is 28.2% of water with respect to the dry silicate) in a weight ratio of 3/1 (carbonate/atomised R2) .

The results are given in Table III.

The amounts of carbonate and of silicate given in this table are expressed on dry basis.

It is found that the performance characteristics of the cogranules are better than those of a mixture of powders having the same silicate/carbonate ratio.

EXAMPLE 14 Particles are prepared from: - 1800 g of pulverulent lightweight sodium carbonate having an average diameter of the order of 110 μτα, and - 1200 g of a solution of sodium silicate having a SiO2/Na2O molar ratio = 3.4 and a solids content of 37%, in a Lodige M5G* mixer, using the method of Examples 6 15 and 7.

After adding the silicate solution for 5 minutes, mixing for a further 5 minutes and standing in the open air for 2 hours at ambient temperature, a product is recovered which has the following characteristics: - sodium carbonate : 60% by weight - silicate * 20% by weight - water associated with the silicate % by weight (which is 100% with respect 25 to the dry silicate) - average diameter » 400 μτα This product is introduced by dry mixing into additives in order to obtain the following laundry detergent composition: Composition of the detergent - linear alkylbenzenesulphonate - Cemulsol DB 618* - Cemulsol LA 90* (surfactants from S.F.O.S) - zeolite 4A - product from Example 14 - Sokalan CP5* (copolymer from BASF) - carboxymethylcellulose - Tinopal DMSX - Timopal SOP (brighteners from Ciba-Geigy) - Esperase* (enzyme from Novo) - Rhodorsil 20444* (anti-foam from Rhfine-Poulenc) - Na perborate.4H2O - TAED parts by weight .8 1.5 0.2 0.2 0.3 pH (10g/l) - 10.25 The performance test for soil removal is carried out in a FOM 71* washing machine from Wascator.

The test conditions are as follows: - cycle used : 60*C - total duration of the cycle : 70 minutes, no pre-wash - number of cycles : 3 per detergent - water hardness : 32° French water hardness - laundry load : 3.5 kg of white cotton cleaning rags - fabrics tested : per wash, the following two series of fabrics are introduced by pinning them to cleaning rags: Grey cotton : Test-Fabric Krefeld 10 C IEC 106 EMPA 101 Polyester/grey cotton : Test-Fabric Krefeld 20 C EMPA 104 Protein stains : Blood (EMPA 111) Cocoa (EMPA 112) Mixed (EMPA 116) Oxidisable stains : Tea (Krefeld 10 G) Unbleached cotton cloth (EMPA 222) Wine (EMPA 114) - detergent dosages: 1st series : 5 g/1, which is 5 x 20 * 100 g per wash 2nd series : 8 g/1, which is 8 x 20 « 160 g per wash Method for determination of soil and stain removal Photometric determinations (determinations of the amount of light reflected by the fabric) enable the percentage soil removal to be calculated. An Elrepho 2000 apparatus from Datacolor is used.

The soil removal is expressed by the equation: C - B Removal in % --------x 100 A - B A = reflectance of the white reference sample B = reflectance of the soiled reference sample C = reflectance of the soiled sample after washing The reflectances are determined with the aid of the blue trichromatic component, without the action of optical brighteners.

Number of measurements carried out per sample = 4 Number of samples per wash = 2 Number of washes = 3 This is equivalent to 4 x 2 x 3 24 measurements per soil, per product and per concentration studied.

The antiincrustation performance test in a washing machine is carried out in a Schultess Super 6 De Luxe* drum machine.

The test conditions are as follows: - cycle used : 60°C - total duration of the cycle = 65 minutes; no pre-wash - number of cycles : 25 cumulative washes - water hardness : 21.2° French water hardness - test fabric used : reference strip corresponding exactly to the specifications given in the Standard NFT 73.600 - laundry load : 3 kg of 100% cotton terry towelling - detergent dosages : 5 g/1 The test pieces which have been subjected to 10 25 washes are dried: they are weighed and calcined at 900°C.

The % by weight of ash relative to the weight of the initial test pieces is determined.

The results of the various tests are given in Table IV.

EXAMPLE 15 A detergent analogous to that of Example 14 is prepared by replacing the builder mixture zeolite 4A + product of Example 14 + Sokalan CP5 by the following builder mixture: - zeolite 4A 30 parts - sprayed silicate R2 3 - lightweight carbonate 6 - sodium sulphate 4.8 - Sokalan CP5 4 The results of the soil removal and anticaking tests are given in Table IV.

EXAMPLES 16 - 18 The product of Example 8 is introduced, by mixing in a Lodige M5G*, into additives in order to obtain dishwashing compositions.

These compositions are given in Table V.

These compositions are tested in a Miele* domestic dishwasher, the water softener of which is not regenerated; because of this it supplies a hard water having a total hardness of 30° French water hardness. cumulative washes of initially perfectly clean plates of soda-lime glass are carried out with each composition, used in a concentration of 3 g/litre of water.

The plates are then subjected to photometric measurement using a Gardner apparatus, identical to that used in Examples 1 to 5.

The total amount of light L reflected by the sample is determined.

If L is between 4 and 7, the result is considered very good; the glass is clear.

If L is between 7 and 14, a slight haze is visible.

The product of Example 8 is compared in a formulation fairly close to a mixture of cogranules of sodium carbonate and cogranules of Britsil H20* (having a SiO2/Na2O ratio 2 and containing 20% of water marketed by Philadelphia Quartz).

The results are given in Table V.

It is found that the use of cogranules of Example 8 enables the amount of sodium citrate (expensive) and polyacrylate (not biodegradable) to be reduced. - ΠΛΟ» Ό fM ·Η Ms Sa* a3* aaa i-nm •ΜΓ4.-4 CM O 8 0 0* «Μ *ΚΌ *· r>NO ..CM «I cNinrs • 0 · <Λ • Htt*3 β» Ό Ο» CM I HNH «Ο 5 5 fc s h? 3 g 4 C s I SH ιΛ MfMW«)OrM<*>CI« a··*·»··· βΦΛΧίίΧΜήβ imnwwinnx in cm c*o a a CMO mc m Ok cnxceecce • •••••••a NneioNOmbO Mkocn«Mcoi 45.65 54.47 rH »l hh z! γΜ kM Mt P5WH J? O' 8» iC tt ifieHH mat b •X.·*· C fl ιΛ«δ o g gjf^i Jj2 ine tt h M u 1 shmih hhhhI General General

Claims (33)

1. Builder agent for a detergent composition, characterised in that it consists of an alkali metal silicate, in particular sodium silicate or 5 potassium silicate, containing at least 30% of silicon atoms in Q 2 and Q 3 form.

2. Builder agent according to claim 1, characterised in that it consists of an alkali metal silicate, in particular sodium silicate or potassium 10 silicate, containing at least 50% of silicon atoms in Q 2 and Q 3 form.

3. Builder agent according to claim 1 or 2, characterised in that it consists of an aqueous solution containing about 10-60% by weight of dry solids of 15 an alkali metal silicate, in particular sodium silicate or potassium silicate, having a SiC^/M^ molar ratio of the order of 1.6 to 3.5.

4. Builder agent according to claim 1 or 2, characterised in that it consists of an aqueous 20 solution containing about 10-60% by weight of dry solids of an alkali metal silicate, in particular sodium silicate or potassium silicate, having a SiO 2 /M 2 O molar ratio which can range from 1.6 to 3.5, adsorbed and/or absorbed on a particulate support which is inert with 25 respect to the silicate, the ratio by weight of silicate expressed on dry basis/water remaining associated with the silicate ranging from 100/120 to 100/40.

5. Builder agent according to claim 4, characterised in that the support represents from 55 to 95% of the weight of the supported solution, expressed on dry basis. 5

6. Builder agent according to claim 4 or 5, characterised in that the said support is sodium carbonate, sodium sulphate, sodium borate, sodium perborate, sodium metasilicate, a phosphate or polyphosphate, such as trisodium phosphate, sodium 10 tripolyphosphate and the like, or a mixture of these salts.

7. Process for the preparation of the builder agent which is the subject of any one of claims 4 to 6, by adsorption and/or absorption by 15 bringing a concentrated aqueous solution of an alkali metal silicate having a SiO 2 /M 2 O molar ratio of the order of 1.6 to 3.5, and having a dry solids content of order of 10 to 60%, into contact with an inorganic support which is inert with respect to the silicate, 20 the said support being present in an amount such that the amount of water remaining associated with the said silicate after adsorption and/or absorption corresponds to a ratio by weight of silicate expressed on dry basis/water associated with the silicate of the order 25 of 100/120 to 100/40.

8. Process according to claim 7, characterised in that the operation for bringing into the contact is carried out by spraying of the said concentrated silicate solution onto the support in particulate form at a temperature of the order of 20 to 95°C.

9. Spherical cogranules of hydrated alkali 5 metal silicates and alkali metal carbonates capable of being obtained by a process characterised in that: - an aqueous solution based on alkali metal silicates or based on a mixture of alkali metal silicates and alkali metal carbonates is sprayed onto a rolling bed 10. Of particles based on alkali metal carbonates travelling in a rotary granulating device, the speed of travel of the particles, the thickness of the rolling bed and the flow rate of the sprayed solution being such that each particle is converted into a plastic 15 cogranule on coming into contact with other particles, - the cogranules obtained are subjected to a densification operation, and - the said densified cogranules are dried until a content of water associated with the silicate 20 corresponding to a ratio by weight of silicate expressed on dry basis/water associated with the silicate of the order of 100/120 to 100/40 is obtained.

10. Cogranules according to claim 9, characterised in that the sprayed aqueous solution 25 based on silicate or silicate/carbonate mixture has a dry solids content of the order of 30 to 55% by weight, the said alkali metal silicate having a SiO 2 /M 2 O molar ratio of the order of 1.6 to 3.5, and it being possible for the said carbonate to be present in proportions depending on the desired end product.

11. Cogranules according to claim 9 or 10, characterised in that the spraying of the solution 5 based on silicate or silicate/carbonate mixture is carried out at a temperature of the order of 20 to 95’C.

12. Cogranules according to any one of claims 9 to 11, characterised in that the particles 10 forming the rolling bed are based on an alkali metal carbonate having; - an average diameter of the order of 10 to 150 microns, - a non-bulk density of the order of 0.4 to 1.1 g/cm 3 , 15 - a water content of the order of 0.05 to 0.4%, and - a proportion of insoluble matter of the order of 5 to 100 mg/kg.

13. Cogranules according to any one of claims 9 to 12, characterised in that the particles 20 forming the rolling bed contain less than 10% of the weight of the cogranules of particles of a type other than an alkali metal carbonate and have a diameter and a density close to those of the alkali metal carbonate particles . 25

14. Cogranules according to any one of claims 9 to 13, characterised in that the granulating device is a rotary granulator permitting movement of the particles as a thin layer.

15. Cogranules according to claim 14, characterised in that the rotary granulator is a dish.

16. Cogranules according to any one of claims 9 to 13, characterised in that the granulating 5 device is a drum.

17. Granules according to any one of claims 9 to 16, characterised in that the carbonate-based particles travel at a temperature of the order of 15 to 200°C. 10

18. Granules according to any one of claims 9 to 17, characterised in that the amounts of solution based on silicate or silicate/carbonate mixture to be sprayed and of carbonate-based particles to be used correspond to a liquid flow rate/particle flow rate 15 ratio which can range from 0.2 to 0.8 1/kg, these values being expressed as sodium salts.

19. Cogranules according to any one of claims 9 to 18, characterised in that the densification operation is carried out at ambient temperature by 20. Rolling the cogranules obtained in the granulation step in a rotary device.

20. Cogranules according to claim 19, characterised in that the densification operation is carried out in a rotary drum. 25

21. Cogranules according to any one of claims 9 to 20, characterised in that the cogranules obtained after densification are dried in a fluidised bed.

22. Cogranules according to any one of claims 9 to 21, characterised in that small amounts of liquid compounds commonly used in the detergent field are added, by spraying, to the cogranules obtained 5 after drying.

23. Spherical cogranules based on alkali metal silicates and alkali metal carbonates, characterised in that they have: - a silicate content of the order of 8 to 38% by 10 weight, said silicate having a SiO^/M^O molar ratio of 1.6-3,5 - a carbonate content of the order of 47 to 87% by weight, - a water content of the order of 5 to 25% by weight, - a non-bulk density of the order of 0.7 to 1.5 g/cm 3 , 15 and - a median diameter of the order of 0.4 to 1.8 mm, with a log 10 standard deviation of 0.02 to 0.3.

24. Spherical cogranules of hydrated sodium silicate and of sodium carbonate, characterised in that 2 0 they have: a silicate content of the order of 24 to 31% by weight, said silicate having a SiO^/Na^O molar ratio of 1,8-2.6 a carbonate content of the order of 64 to 69% by weight,

25. - a water content of 12 to 20% by weight, a non-bulk density of the order of 0.7 to 1.5 g/cm 3 , preferably of the order of 0.8 to 1, a median diameter of the order of 0.4 to 0.8 mm, with a log 10 standard deviation of 0.05 to 0.1, and a speed of less than 2 minutes for 90% dissolution in water and of less than 4 minutes for 95% dissolution in water. 5 25. Builder agent comprising the cogranules which are the subject of any one of claims 9 to 24.

26. Use of the builder agent which is the subject of claim 3 in pulverulent detergent 10 compositions, in post-addition by spraying onto the detergent powder at the bottom of a tower or onto a mixture of components of the detergent formulation, the weight ratio of dry silicate/detergent powder or formulation being between 1/100 and 30/100 and the 15 weight ratio of dry silicate/water remaining associated with the silicate being between 100/120 and 100/40.

27. Use of the builder agent which is the subject of any one of claims 4 to 8 and 25 in pulverulent detergent compositions for a dishwashing 20 machine in an amount of 3 to 90% by weight of dry silicate with respect to the composition.

28. Use of the builder agent which is the subject of any one of claims 4 to 8 and 25 in pulverulent detergent compositions for a washing 25 machine in an amount of 3 to 60% by weight of dry silicate with respect to the composition.

29. A builder agent according to claim 1 or 25, substantially as hereinbefore described and exemplified.

30. A process for the preparation of a builder agent according to claim 1 or 25, substantially as hereinbefore described and exemplified.

31. A builder agent according to claim 1 or 25, whenever prepared by a process claimed in any one of claims 7, 8 or 30.

32. A spherical cogranule according to any one of claims 9, 23 or 24, substantially as hereinbefore described and exemplified.

33. Use according to any one of claims 26-28, substantially as hereinbefore described and exemplified.