Sodium percarbonate containing compositions

The present invention relates to a detergent composition containing sodium percarbonate, especially detergent compositions that contain an additional component, which interacts with the additional component and sodium percarbonate in a destructive manner.

Detergent compositions, and particularly certain detergent compositions intended for domestic washing of general-purpose fabrics or for specialized applications such as disinfecting nappies or washing dishes, often contain in addition to one or more surfactants, a builder, bleach and, optionally, fillers. , technological adjuvants and small amounts of certain other adjuvants (adjuvants), including one or more additives, such as optical brightener, complexing agents, fragrances and dyes. Traditionally, the builder is selected from inorganic phosphates, such as sodium tripolyphosphate, because of the beneficial properties of phosphates in washing fabrics. However, it turned out that phosphates cause or contribute to eutrophication, and one of the sources of phosphates is sewage from domestic and industrial fabric washing. As a consequence, and due to increasingly stringent legal regulations in various countries, the detergent industry has been looking for an alternative to phosphates in recent years. One of the possibilities is a very important category, namely zeolite-containing substitutes.

The bleach component usually comprises a peroxy compound, a preferred example for solubility and other properties of which is sodium carbonate peroxyhydrate. This compound is usually called sodium percarbonate and is also referred to in the present invention as such. However, sodium percarbonate and other detergent ingredients can interact destructively with each other.

This results in a gradual degradation of the percarbonate and hence a loss of its whitening ability during storage and transportation of the composition, a problem particularly apparent when the detergent builder comprises zeolites.

Attempts have been made in various ways to overcome or remedy the problem of the degradation of sodium percarbonate in zeolite detergent compositions. Overall, the proposals relate to two methods. In the first method presented in EP-A-0451893, Unilever, the selection of the sodium percarbonate particle size distribution was made according to a given formula. More specifically, the formula favors an average particle size of at least 400 micrometers and a narrow particle distribution. This method only uses the large outer dimensions of the carbonate to determine which molecules are larger and which are smaller.

However, sodium percarbonate generally has a porous or irregular outer layer so that large dimensions do not directly determine the effective surface area of ​​the carbohydrate. The regularity and porosity of the outer surface of sodium percarbonate varies with the method of production. This is the next and very important factor that directly affects the effective surface area and the stability of the percarbonate.

A second frequently described method of improving the stability of sodium percarbonate is to coat the surface of the percarbonate with a surface layer of material that is physically inserted between the surface of the percarbonate and another given component of the composition. The effectiveness of the coating in inhibiting and improving the rate and extent of decomposition of percarbonate depends on the type of coating material used and the overall coating. While certain coating materials are described which are advantageous in inhibiting decomposition of zeolite detergent compositions, including especially coatings containing sodium borates, Kao Soap, US-A-4,526,698, is silent about the inherent stability of uncoated percarbonate. Similar to WO 95/15291, Kemira, which describes the use of carbon dioxide gas in contact with wet percarbonate during the coating operation to improve the resulting coated percarbonate stability.

As in the Kao Soap disclosure, there is no information here on the stability of uncoated percarbonate.

The continued desire to include both zeolites and sodium percarbonate in a detergent composition, and particularly in concentrated and ultra-concentrated detergent compositions, means that there is a continuing need to find still other and / or better ways to improve.

186 136 percarbonate stability and / or determining how to appropriately select a product with improved and optimal stability from the various production methods of sodium percarbonate.

Moreover, however, at least in some places around the world, a significant proportion of the laundry compositions or compositions containing bleach additives are largely zeolite builder, or even free from zeolite builder, so it would also be advantageous from a commercial standpoint. improving or optimizing the stability of the sodium percarbonate contained in such compositions.

The most important object of at least some aspects of the present invention is to provide different and / or improved detergent compositions containing both sodium percarbonate and zeolite.

According to the present invention, a detergent composition comprising sodium percarbonate in an amount of 2-40 wt.%, 5-60 wt.% Of a builder, 2-40 wt.% Of one or more surfactants, optionally one or more anti-redeposition agents, soil suspending agents, bleaching activators, optical brighteners, anti-sticking agents, suds regulators, enzymes, fabric softeners, fragrances, dyes in a total amount of up to 20% by weight and optionally one or more auxiliaries in an amount of 0-30% by weight, characterized in that sodium percarbonate has an average particle size of 500 to 1000 microns and not more than 20% by weight below 350 microns and has a hydration level measured in the test at 80% relative humidity and 32 ° C after 24 hours, not greater than 30 g / 1000 g of sample.

In a preferred embodiment of the invention the sodium percarbonate has an average particle size of 500 to 850, especially 600 to 850 microns, and a hydration level of no more than 15 g / 1000 g in the test.

In a further preferred embodiment of the invention, the sodium percarbonate has been coated with a layer of 1 to 20%, preferably 2 to 5% by weight of an inorganic and / or organic coating, the coating layer preferably not or not more than 2.5% by weight of chloride, calculated as NaCl in relation to the sodium percarbonate.

The composition according to the invention preferably comprises 5 to 25% by weight of sodium percarbonate.

As builder, the composition according to the invention preferably comprises a zeolite builder, preferably in an amount of from 10 to 30% of the zeolite builder.

In another embodiment of the invention, the builder composition comprises a phosphate builder.

In a further preferred embodiment of the invention the composition comprises sodium percarbonate having a hydration level of up to 30 g / 100 g obtained by crystallization of sodium percarbonate from its saturated aqueous solution limited to halides.

Preferably, sodium percarbonate is crystallized from the solution by adding a salting agent which is not a sodium halide.

In another preferred embodiment of the invention, the composition comprises sodium percarbonate crystallized from solution in the absence of a salting agent.

In a further embodiment of the invention the composition comprises sodium percarbonate classified to remove too small and too large particles and leave a product having a particle size of 500 to 1000 microns and no more than 20 wt% below 350 microns and having a hydration level as measured by a humidity test. relative 80% and at 32 ° C after 24 hours, not more than 30 g / 1000 g of sample.

In a further embodiment the composition of the invention comprises sodium percarbonate having a heat emission after 7 days of aging at 40 ° C of less than 3 (t & lt; 2 & gt; W / g for 16 hours.

The method for selecting sodium percarbonate for inclusion in a builder containing composition is characterized by carrying out any order of steps

1) measuring the distribution of kdc and total particles, determining the size of the particles and the part by weight below 350 micrometers, and discarding from the first stage material that has an average particle size outside the range of 500 to 1000 micrometers or contains more than 20% by weight below 350 micrometers, and

186 136

2) measuring the degree to which the moisture is captured / captured in the material in a 24-hour test at 32 ° C 1 and 80% relative humidity and the rejection of material that captures more than 30 g of moisture per 1000 g of material. The retained material meets the accepted standards for sodium percarbonate with regard to its particle size and degree of nwudo-1o.

By selecting sodium percarbonate, which simultaneously has the desired particle size distribution and the appropriate degree of hydration in specific tests, it is possible to identify sodium percarbonate that has greater stability in the formed composition, such as a particularly zenith detergent composition, compared, for example, with the inclusion of available commercially unpainted sodium percarbonate which does not meet any or only one of the selected parameters.

It is recognized that it is possible to produce and isolate different sodium percarbonate products having the same or similar particle size distribution, but significantly different hydration levels, by selecting the production process and by appropriate selection of mop / output parameters for the selected production process. These different products have different stability with respect to degradation in the formulated composition, and particularly, in a toll detergent composition. Some will be better, some will be worse, and the choice as to which sodium percarbonate is better to use can be made using the twin test methods of the invention.

Without being bound by any particular theory or opinion, it is believed that the level of hydration measured by the test is likely to indicate the degree of n1 interest and / or porosity of sodium percarbonate that is present in the atmosphere, while the particle size distribution indicates physical contact between the constituents in question. composition, and that, when considered together rather than singly, two studies provide a clear basis for selecting sodium percarbonate actually having relatively good stability in the presence of zeulite builder and, indeed, also in the presence of other active compounds.

It is preferred that the sodium percarbonate particles are generally in the range 250 to 1250 microns, particularly at least 80% and preferably at least 95% of the mosumnch particles are in the range 350 to 1000 microns. It is especially desirable to use sodium percarbonate which has an average particle size of from 500 to 850 microns and preferably 600 to 850 microns. A product having an average particle size of at least 600 microns, and particularly at least 650 microns, and a particle distribution range of 0.9 to 1.2, will often meet the particle size criteria without undergoing further classification. From the point of view of percarbonate stability, it is desirable to avoid relatively small particles, such as particles below 350 micrometers, especially those below 250 micrometers, or aminimolysomone. Relatively large particles, such as those greater than 1000 microns in diameter, do not reduce stability but may separate to a greater extent from smaller components of the composition.

The particle size distribution of a given sodium percarbonate can be determined by the standard method of prating a representative sample of material by a set of screens of known decreasing mesh size and weighing the portion of material retained on each screen. The accuracy of the measurement increases as the number of sieves increases. In an alternative measurement method, a given product is subjected to a laser beam and the resulting scattered light is eliminated, for example, using a particle size analyzer available under the trade name Makem 2600 C.

The particle size distributions reported in the present invention can be obtained by one or more of the following methods. In the case where a crystallization process is used, an external classification may be used, for example, dry percarbonate and / or ainttspomoon mtrann classifier combined with the crystallizer and the classification of the percarbonate molecules in the liquid medium, respectively to induce the desired fraction or produce the desired range of percarbonate molecules. For example, a product having an average dry particle size in the range 500 to 700 micrometers

186 136 can easily be obtained from a dry product using a standard "wet" production process by sieving and separating generally all particles below a certain sieve size, such as 350 microns, thus leaving a fraction that typically ranges from 350 to about 850 microns and a peak in the range of about 500 to 600 microns. By sieving to isolate the product below a larger sieve size, e.g. 500 pm, it is possible to obtain a product with a higher mean particle size, e.g. 600 to 700. Alternatively or additionally, particles above the upper size, such as 1250 or 1000 microns, may be removed so as to leave a narrow range. It will also be recognized that the particle size distribution of the product obtained from the production process may be different due to the control of the process parameters. Hence, in a crystallization process, by controlling the rate of seed formation depending on the growth in the crystallizer and avoiding or minimizing the introduction of the seed obtained, the average particle size of the resultant product can be increased.

In a further embodiment, the particle size distribution of sodium percarbonate having an average particle size of less than 500 µm may be increased to the desired range by a particle granulation / agglomeration process, typically with an aqueous solution of a known agglomerating / granulating agent for alkaline materials sprayed onto the percarbonate in a standard apparatus. such as a granulating screen receiver. For example, water-soluble coating agents for sodium percarbonate, such as silicate, may suitably be used under the process conditions appropriate for granulation to bind the percarbonate molecules together rather than forming just a coating.

It is particularly advantageous to use crystallized sodium percarbonate which has been obtained by a process in which the classifier is integrated with the crystallizer and which is operated to separate particles above and below the desired minimum size, but in the classifier larger particles are obtained as a product while smaller particles are obtained. they are reintroduced into the crystallizer where they can grow as a result of the accumulation of additional sodium percarbonate from the solution, typically by adding a salting agent to a saturated or supersaturated sodium percarbonate solution in a crystallizer. The enlarged particles flow back to the classifier. Such a classifier / crystallizer combination is particularly advantageous in that, by appropriate control of the operation, it is possible to control the particle size during production rather than having to be applied externally and thus an additional classification process. The product usually has a particle distribution similar to the "normal" one. Its scope depends on the type of device used. It is often from about 0.6 to about 0.9. Typically at least 80% of the product particles, and often at least 90% by weight of the particles, are in the range of +/- 50% of the average particle size, with an average particle size greater than 600 to 1000, and in many cases from 650 to 850 micrometers.

A further process by which sodium percarbonate can be produced in the desired particle size range is a crystallization process carried out at a sub-stoichiometric ratio of hydrogen peroxide to sodium carbonate, particularly in the order of 0.8-1.2: 1. The mother liquor recycled to the crystallizer is below the concentration carbonate saturation, and crystallization is carried out without adding a salting agent.

Advantageously, a process that avoids a salting-out agent, such as sodium chloride, which is easily co-precipitated with sodium percarbonate, and especially processes that avoid the use of a salting-out agent, can provide a high purity product, e.g. Avox (active oxygen) with a value of at least 14.5% and in some cases Avox with a value of at least 14.8%.

The above crystallization processes can of course be carried out with crystal habit stabilizers and modifiers such as sodium silicate, polyphosphonic acids, phosphates and homo or copolyacrylates as is well known in the art, although greater benefits are obtained when no salting agents are used such that residual peroxide concentrations can be higher than those in chloride salt processes. In many cases, the resulting product has a smooth round shape which facilitates close packing

186 136 and allows to obtain a bulk density in the range of 800 to 1100 g / 1000 g in the standard free flowing bulk density test.

Alternatively, for example, where the given sodium percarbonate is obtained by evaporating the solvent from the sodium percarbonate solution or reactant solutions to obtain sodium percarbonate in situ, which is / are suitably sprayed onto a layer of sodium percarbonate particles, e.g., fluidized by a jet of an inert gas drying gas , e.g. air, the process can be continued until the desired particles are obtained which are at least the minimum size which provides an average particle size of at least the widest range of 500 to 1000 micrometers. In such a fluidized layer process, it is possible to choose operating conditions that reduce or minimize seed formation through the in situ physical disintegration of existing particles in the layer and minimize the introduction of externally produced seed, thus again contributing to the formation of a larger particle size product.

A second important property of the sodium percarbonate used in the compositions of the invention is the extent / degree to which moisture is taken up from the humid atmosphere. In the present invention, including the examples and comparative compositions specifically given, the moisture scavenging capacity of sodium percarbonate is measured by the following test:

A petri dish, 9 cm in diameter and 1 cm deep, is weighed accurately on the balance with an accuracy of 4 decimal places (Wl). A sample of dry sodium percarbonate (approximately 5 g) is placed in a petri dish, which is gently shaken to form an even layer at the bottom of the dish and reweighed on the same scale (W2). The sample in the Petri dish is kept in a room approximately 3 m high, wide and long in an atmosphere maintained for 24 hours at 32 ° C by a thermostatically controlled heater at 80% relative humidity (RH), by introducing a spray of water in the form of fine particles droplets by controlling the humidity with a humidity detector and weighing on the same scale (W3).

The samples are protected by a shield created by a spray of liquid.

The sodium percarbonate hydration level is calculated as follows:

Hydration level (g / kg) =. 1000 x (W3 - W2) (W2 -Wl)

Depending on the production method, the range of the level of hydration with sodium percarbonate in the test can vary very widely, from a low value that is below 10g / 100Og, such as 1-5g / 1000g, to a value that is within the range from 100 to 200g / 1000g. The latter products are outside the scope of the invention. Products with a hydration level between 15 and 30 g / 1000 g in the test can be obtained by other production methods. Their use in zeolite compositions is in accordance with the present invention, although it is preferable to select products with low (i.e. up to 15g / 1000g) or especially the lowest level of hydration.

It has been found that the extent of hydration is influenced by substances such as salting out agents used to support the percarbonate crystallization process. Traditionally, sodium chloride has been the most important salting-out agent because it is readily available and is an effective aid to the crystallization process. Currently, however, it is found that its use is not beneficial as it contributes to an increase in the level of hydration. As a consequence, and to control the level of sodium percarbonate hydration, it is particularly desirable that the sodium chloride fraction in the salting-out agent be controlled so as to ultimately provide no more than a small proportion of sodium (by mole), such as, for example, no more than 10%. It is especially desirable to use mainly chloride-free salting out agent, i.e., at a level no greater than that of the impurity. Sodium sulfate has been used as the salting out agent in particularly preferred processes for the preparation of sodium percarbonate with the desired low level of hydration. In another particularly suitable process for obtaining a low hydration product, crystallization can be carried out in the absence or substantial absence of added salting agent, for example by not using a salting agent in the process described in EP-A-0703190.

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It will accordingly be recognized that if a coating agent is used, at least in part, to granulate the acceptable sodium percarbonate to increase its mean particle size above 500 µm, appropriate limitations regarding the presence of chloride in the coating agent are desirable.

It is recognized that it is particularly advantageous for a sodium percarbonate producer to use a sodium percarbonate production process that will be controlled to obtain a product having both a low level of hydration and a narrow particle size distribution with an average in the range of 500 to 1000 micrometers. Such a production process employs a combination of percarbonate crystallization in an integrated crystallizer / classifier as described in the present invention, and the use of sodium sulfate or other similar non-chloride sodium salt as a salting agent. Indeed, particularly suitable processes include those in which no salting agent is used.

One type of device that can be advantageously used in the production of sodium percarbonate with actually acceptable properties, assuming that the correct choice of a salting out agent, if used at all, is described in EP-A-703 190 Solvay Interox SA.

The detergent composition of the present invention often comprises sodium percarbonate, which has a combination of an average particle size of 500 to 1000 (α) and a hydration level of no more than 30 g / 1000 g when tested in an amount of at least 2%, and in many cases at least 5% by weight. greater than 40%, and in many cases up to about 25% by weight of the composition.

It is recognized that sodium percarbonate having the above combination of the defined characteristics of particle size and level of hydration may be incorporated as such in a zeolite or other detergent composition or may optionally serve as a convenient and advantageous coating base so as to then combine its proper stability with that obtained. thanks to the coating. The amount of such coating is usually selected in the range of 0 to 20% by weight, based on sodium percarbonate, and a convenient amount is often selected in the range of 1 to 5% by weight. It is particularly desirable to choose a coating material which increases rather than nullifies the improvement in stability achieved by proper sodium percarbonate. As a result, it is preferable to use a coating that excludes soluble halides, such as especially sodium chloride, from the coating, or not to use more than the acceptable amount, such as not more than about 2.5% based on sodium percarbonate. In view of the chloride restrictions, the coating materials often preferably contain one or more materials selected from alkali metal and / or alkaline earth metal, particularly sodium or soluble magnesium, mineral salts or other inorganic acids, particularly sulfate, carbonate, bicarbonate. , phosphate and / or polyphosphates, silicates, borates and the corresponding boric acids. The coating may additionally or alternatively contain water-soluble acids and metal salts of chelating agents such as aminoethylene polycarboxylate groups, aminoethylene polymethylene phosphonates, including the well-known EDTA, DTPA (diethylene triaminepentaacetic acid), EDTMPA (ethylenediaminotrimethylenephosphonic acid), and DTPMPA and diethylene triphosphonic acid, and diethylenetophosphate (diethylenetophosphate) hydroxycarboxylic compounds such as citrate, tartrate or gluconate. The other ingredients may contain fatty acids (e.g. up to C20) and / or the corresponding amides.

A particular combination of coating agents comprises carbonate / sulphate and boma acid or borate with sulphate and a combination of a) sulphate, carbonate / sulphate, bicarbonate, boric acid or borate alone or with sulphate, citrate or citrate / sulphate, gluconate or gluconate / sulphate b) a silicate and / or carboxylate or phosphonate of a metal chelating agent.

A wide variety of zeolite builders, sometimes alternatively referred to as aluminosilicate builders, may be included in the compositions of the invention. Suitable zeolites typically exhibit a significant ion exchange capacity with respect to calcium (or other alkaline earth metal) (i.e. water hardness) expressed as CaCO equivalent, at least 150 mg CaCO₃ na g and for most of the preferred zeolites

186 Exchangeability based on ions which make the water hardness from 200 to about 350 mg of CaCO equivalent₃ on g.

The number of such zeolites often follows the general empirical formula M._with [(A1O₂)_WITH (Si0₂)_y] xH₂0, wherein M is an alkali metal, preferably sodium, and y are both at least 6, and the molar ratio is y: z from 1: 1 to 2: 1 and is at least 5 and preferably from 10 to about 280. Many zeolites are hydrated, containing up to about 30% by weight of water, such as from about 10 to about 25% water bound in the material. Zeolites can also be amorphous although most preferred zeolites are crystalline.

While some aluminosilicates occur naturally, most are synthetic. Appropriately defined crystal zeolites of well known structure and formula include zeolite A, zeolite X, zeolite B, zeolite P, zeolite Y, zeolite HS, and zeolite MAP.

The percentage of zeolite in the composition is often at least 5% and in many cases at least 10% by weight. Typically it is not more than about 60%, often not more than 50%, and in many cases not more than 40% by weight of the composition.

The zeolite used in the present invention can be prepared in a manner that reduces or minimizes subsequent attack on the bleach in the composition, such as by controlling the moisture content, preferably below equilibrium, as described, for example, in WO 95/05445.

It will be understood that in modifying the invention, at least one aspect of the invention is directed primarily to compositions comprising one or more zeolite builders in combination with a selected percarbonate. A similar benefit in terms of improved percarbonate stability can be seen by selecting the percarbonate used in the same way in combination with amorphous or specially layered zeolite replacing silicates in the same weight proportions, albeit on a smaller scale due to their lower interaction with the percarbonate. These crystalline layered silicates often have the empirical formula Na₂Si_xO2x-iyH₂O or the corresponding compounds where the sodium ion is replaced by hydrogen where x is selected from 1.9 'to 4 and y is selected from 0 to 20 as for example disclosed in EP-A-164 514. In a modification of the invention, such layered silicates are used in the absence of zeolites.

The detergent compositions of the present invention usually contain one or more surfactants, often present in total in an amount of from 2 to 40% and especially 5 to 25% by weight.

The surfactants included in the solid compositions of the present invention may be selected from particular or flake, anionic, cationic, nonionic, zwitterionic, amphoteric and ampholytic surfactants and may be natural or synthetic soaps. Some suitable surfactants are described in Chapter 2 of Synthetic Detergents by A Davidson and BM Milwidsky (6th edition) published in 1978. by George Godwin Ltd and John Wiley & Sons, incorporated herein by reference. Without being limited to these surfactants, representative subclasses of anionic surfactants are soaps, aralkyl sulfonates, olefmosulfonates, linear alkane sulfonates, hydroxyalkane sulfonates, long-chain oxyethylated alcohol sulfates, sulfonated glycerides, sulfonated glycerides, sulfonated ethersulfonates, sulfonated ethers. sucrose and anionic fluoro surfactants; representative classes of cationic surfactants include quaternary ammonium salts or quaternary pyridine salts containing at least one alkyl hydrophobic or aralkyl group; representative classes of nonionic surfactants include condensates of long chain alkanols with ethylene oxide polymers or phenols or condensates of long chain carboxylic acids or amines or amides with polymers of ethylene oxide and related compounds in which the long chain moiety is condensed with an aliphatic polyol such as sorbitol or the condensation products of oxides ethylene and propylene or fatty acid alkanamides and fatty acid amine oxides; representative classes of amphoteric / zwitterionic surfactants are sulfo10

186 136 ionic or phosphonium surfactants, optionally substituted with an anionic dissolving group. The surfactant ratio, expressed as part of the total surfactant present, is often from 2/10 to 8/10 anionic, from 0 to 6/10 non-ionic and from 0 to 3/10 for other surfactants. .

The zeolite need not contribute to the total builder content of the composition, and even in some forms it may not be present at all. Such non-zeolite builders can be present in the standard builder range, i.e., from about 5 to 60%. It is essential, however, that according to the present invention, the sodium percarbonate is selected on the basis of a twinning screening exercise, namely the specific level of hydration and the particle size distribution. Other detergency builders which are suitable for inclusion in the compositions according to the present invention include especially the aforementioned layered alkali metal phosphates, especially triphyphosphate, but also tetra-pyrophosphate and bisphosphate phosphate, especially sodium salt of each, alkali metal, preferably carbonates. sodium, alkali metal silicates and an alkali metal, preferably sodium borates. As yet a further class of builders which can be incorporated comprises organic chelating builders such as amniopolikarboksylany and aminnpnlimgtylgnnfnsfoniany or hydroksyfosfoniany, including nitrilotriacetate or trójmetylgnnfosfonian, gtylgnndwuaminocztgrooctan or cztgromgtylenofosfnniαn, dwuetylenotróraminopięcinmgtylgnnfosfnnian or cyklohekasano-l, 2-dwuαminoczterometylennfosfnnian, normally completely or partly in the form of sodium salt. Chelating carboxylate builders include monomeric or oligomeric carboxylates including glycolic acid and ether derivatives, salts and derivatives of succinic and tartaric acids, citrates, cadboxybuduccinates, and pnliaspadgates. Others contain ethane or propane tetracarboxylates and various sulfosuccinates. Such chelating builders can be used in relatively low amounts as a builder enhancer and peroxygen stabilizer, on the order of 1 to 10%. Additional builders containing chelating builders may be present in amounts at the discretion of the manufacturer of the composition, and will overall be no more than about 40% by weight, and in many cases from about 5 to about 20% by weight.

Further and optional ingredients of the detergent composition may include anti-redeposition agents and soil suspending agents, bleach activators, optical brighteners, release agents, suds regulators, enzymes, fabric softeners, perfumes, dyes, and processing aids. In total, optional ingredients often constitute up to about 20% by weight of the composition, and often up to 10% by weight, excluding processing aids which may additionally make up 0 to 30% by weight of the composition, if desired.

Anti-redeposition agents and soil suspending agents are often selected from methyl, carboxymethyl or hydrocayethyl derivatives of cellulose or polyvinylpyrrolidines, and from polymers of polyhydroxylic acids such as copolymers of maleic anhydride with methacrylic acid, ethylene or methyl vinyl ether. Suitably such an agent is present in an amount of at least 0.5% and often from 1 to 5%.

Bleach activators that may be included are usually O-acyl or N-acyl compounds which will generate peroxy acid by reaction with sodium percarbonate. Suitable classes of activators include the activators a1 to a20 described in EP-A-0565017, incorporated herein by reference. Specific activators of importance include TAED (NN-N'N'-tgtraacetylgtylenediamine), SNOBS (sodium nnnanoyl nxybgnosephenate) and its isononoyl counterpart, TAGU (tetdaacgtylglycoluril) and sugar esters. Such activators, when employed, are typically used in the equivalent molar ratio to the percarbonate of from 2: 1 to 1:10 and often at or about 1: 1 or 1: 5 to 1: 8. In many cases this may correspond to a content of between 1 to 8% and particularly 2 to 6% by weight of the composition. The user may then consider including one of the manganese, cobalt or complexes

186 136

In titanium, otherwise known as accelerators, according to the published literature, possibly with a calcium promoter.

Optical brighteners are often selected from suitably substituted aminostilbens and especially from triazinoamnostilbens.

Release agents are often selected from copolymers of terephthalic acid and polymers of ethylene oxide (PEO1 and / or polymers of propylene oxide (PPO).

Often suds regulators are silicones or alkylated silicone materials or finely divided silica aerogels or xerogels.

The enzymes can be selected from amylases, neutral or alkaline proteases, lipases, esterases and cellulases which are commercially available.

Fabric softeners include roller clays (calcium and magnesium aluminosilicate1 clays and water-insoluble tertiary amines, sometimes in combination with long chain quaternary ammonium salts and / or high molecular weight ethylene oxide polymers. The total content of such agents is often selected in a range. 5 to 15% by weight, with the organic component ranging from about 0.1 to 2% by weight.

The processing aids are often selected from sodium and / or magnesium sulfate. In concentrated and ultra-concentrated compositions, they often constitute a relatively small percentage up to about 5%, but in conventional powders they can often constitute from 20 to 40% of the weight of the composition.

Detergent compositions of the present invention are often prepared by dry blending a given sodium percarbonate and sometimes a portion of the zeolite with a blend of the remaining ingredients. A mixture of non-percarbonate / zeolite ingredients may be obtained in a conventional manner by spray drying a paste of these ingredients to form a given mixture or by agglomeration.

It will further be recognized that the benefit of selecting sodium percarbonate by means of a twinning test for inclusion in formulated detergent compositions also applies to other formulations containing the same builders, such as, for example, compositions containing bleach additives that typically contain at least 5% each builder and percarbonate in a weight ratio of 5: 1 to 1: 5.

Detergent compositions are produced on a large scale so that their ingredients, such as sodium percarbonate, in practice must be stored and transported to the detergent storage / production site in large quantities. It is highly desirable to use in detergent compositions such as those set out above sodium percarbonate which has been produced in a crystallizer or a crystallizer / classifier without adding chloride or in many cases particularly without any salting agent, but which gives or can be classified as yielding given product with the desired particle size range and distribution as set out above. It is particularly desirable to select products that exhibit a low degree of heat emission. A representative image that enables a realistic comparison between products made using different processes and at different locations can be obtained by first subjecting the percarbonate samples to a 7-day aging process in a sealed ampoule in a constant temperature chamber kept at 40 ° C, thereby bringing the percarbonate back to its actual value. the level of heat emission. Such aging is given in the present invention by reference to a 7-day aged product. The product is then transferred to a microcalorimeter, model LKB 2277, also known as the Thermal Activity Monitor, which is sold by Thermometric Limited, Sweden. The heat emitted from the sample is measured over a standard time period, which in the present invention is 16 hours and at the standard test temperature, 40 ° C. By comparison, a typical product obtained by a wet process using chloride salting out can often emit 5 to 7 pW / g during 16 hours of testing, while products obtained according to the process of the invention

186 136 emits typically less than 3 (iW / g, often at least 0.5 µW / g, and in many cases from 1 to 2 (iW / g. Products according to the invention having less heat emission may allow the handling and storage of sodium percarbonate in more adverse conditions such as a warmer climate or reduce the need for precautionary measures to remove heat.

It is of practical benefit to choose to include a sodium percarbonate (PCS) product in the detergent composition which not only has a large particle size, preferably a narrow range below 1 and a low MPU below 30 g / 1000 g, but also has a low LKB associated with 7- days of aging below 3 µW / g.

Having described the invention in general terms, specific embodiments of the invention are illustrated in greater detail by way of example only.

In these examples and comparisons, the hydration level and particle size distribution were measured and used as the basis for the selection of sodium percarbonate. Hydration level data shown were obtained from the 80% RH and 32 ° C test as described above in the present invention.

The sodium percarbonate used sequentially in Examples 1-3 was obtained by screening a large sample of sodium percarbonate produced by Solvay Interox and having a low level of hydration through a set of sieves having the mesh sizes shown below to obtain three fractions. Also, the sodium carbonate used in comparisons R1 to R3 was obtained by screening a differently produced sodium percarbonate with a much higher level of hydration through the same set of sieves to obtain 3 fractions. The average particle sizes of the three pairs of corresponding fractions, 1 and R1, 2 and R2, and 3 and R3, were similar.

The sodium percarbonate in Examples 1-3 was obtained by the crystallization method, in which a large amount of aqueous sodium percarbonate solution, saturated or close to saturation, was obtained first by reacting in a solution of hydrogen peroxide and sodium carbonate and then by introducing a chloride-free salting agent - sodium sulfate. to aid in crystallization and precipitation from the sodium percarbonate solution. The crystallization process was carried out in an integrated device containing a crystallizer located above and connected to a classifier. The clarified liquid flowed up through the classifier and crystallizer. The fraction was recycled to the bottom of the classifier. The salting-out agent, sodium sulfate, decreased the solubility of the sodium percarbonate solution introduced into the crystallizer, thereby causing the formation of nuclei as well as the deposition of percarbonate on the percarbonate particles present in the crystallizer. As the particles grow in the crystallizer, they tend to fall down under the influence of gravity in the classifier. The product, mainly consisting of particles with a diameter of at least 400 micrometers, is removed from the lower layer of the crystallizer. Due to the tendency of the sodium percarbonate particles to fall out of the crystallizer as they grow in size rather than to remain inside for further size increase, the resulting product tends to have a much more compact particle size distribution than the product produced by the standard "wet" production crystallization process sodium percarbonate. Thus, while the unscreened product has an average particle size in the range of 600 to 650 microns, there are relatively few particles greater than 899 microns in diameter. The product was dried with hot air.

In comparative formulations, sodium percarbonate was prepared by Solvay Interox's commercial "wet" production method in which sodium percarbonate was reacted in solution with hydrogen peroxide to form a concentrated solution of sodium percarbonate, in the presence of sodium chloride as a salting agent in the solution. The mixture was cooled and thus formation of crystalline percarbonate occurred. As before, the product compared was dried with hot air.

In the examples and comparisons, the detergent composition was prepared by dry mixing 10 wt% sodium percarbonate with 90 wt% of a base detergent composition containing zeolite A (Na) in an amount of about 30 wt%.

Samples (50g) of the mixed composition were transferred to polyethylene lined cardboard boxes and sealed. The cartons were stored in a humidity controlled cabinet at 26.7 ° C (80 ° F) and 80% RH for 6 weeks. The active oxygen (Avox) content of the compositions was measured at the beginning and end of the storage period using the standard method of potassium permanganate titration. The remaining Avox at the end is expressed as a percentage of the original value.

Table 1

<td>Ex. / Compare</td><td>Particle size (im</td><td>Hydration level g / kg)</td><td>% recovery Avoxu</td>

<td> 1</td><td> 600-850</td><td> 10</td><td> 50</td>

<td> 2</td><td> 425-600</td><td> 10</td><td> 32</td>

<td> 3</td><td> 250-425</td><td> 10</td><td> 19</td>

<td>Cl</td><td> 600-850</td><td> 100</td><td> 38</td>

<td>C2</td><td> 425-600</td><td> 100</td><td> 16</td>

<td>C3</td><td> 250-425</td><td> 120</td><td> 0</td>

Table 1 shows that when sodium percarbonate with an actual average particle size of about 500 µm or greater was used in combination with a low level of hydration, it had a stability in the presence of zeolite builder that was significantly and measurably greater than if only one of the two alone was selected. two parameters. In particular, it is observed that the stability of a percarbonate with a very similar particle size range / distribution varied significantly, even though from the disclosure of EP451893 it would be expected that products with the same particle size range (since no coating was applied to modify the stability) would also be very similar; eg the product in Example 2 had twice the stability of the product in C2. The improvement in Avox retention by using low to high hydration percarbonate was consistently around 14 to 18% in the study. This can be seen by comparing the samples with the same particle size fraction e.g. example 2 with C2 and also, the improvement due to the larger particle selection was kept in the range of 14 to 18% as can be seen by comparing the results obtained in examples 1, 2 and 3 .

The results clearly show that the sodium percarbonate selection process based on the twinning measurement of hydration level and particle size is a practical method for selecting sodium percarbonate which is suitable for inclusion in detergent compositions, i.e. material selection in Examples 1 and 2.

In a further set of tests, a sample of sodium percarbonate of the same type as that used before screening in Examples 1 to 3 and having a hydration level of 10 g / 1000 g in the appropriate test was contacted with pure materials considered as coating agents.

It was found that the effect of contact with sodium carbonate, sodium sulfate and sodium silicate, even with 5% of such material, did not increase the corresponding stability factor (hydration level) to more than about 15 g / 1000 g, but that the presence of 5% sodium chloride increased the level of hydration to over 100 g / 1000 g confirming, that it is very important to prevent the presence of excess chloride in order to maintain the advantage of proper stability of the selected percarbonate according to the invention in the subsequent coating operations.

In the next demonstration, Avox stability was measured on sodium percarbonate samples in a given mixture with a detergent composition containing the given zeolite A (Na salt) and layered silicate (SKS-6) as builders. The test was carried out in wax-coated boxes at 32 ° C and a relative humidity of 80%. In Run 4, sodium percarbonate was produced by a method essentially similar to that which gave the products used in Examples 1-3, i.e. an integral crystallizer / classifier, sodium sulphate salting out agent was used, but under controlled operating conditions to obtain a product with an average particle size of about 750 pm po14

186 136 hydration level &lt;10 g / 1000 g. In the test, the next sodium percarbonate sample used in test 4 was coated with a 50/50 w / w mixture of sodium carbonate and sodium sulphate by wetting the percarbonate in question with a concentrated aqueous solution of the coating agents in a scale mixer in a laboratory at about 25-30 ° C to obtain a 3% total dry weight of the coating agents; and drying the wet percarbonate in a fluid bed dryer.

In test C6 (comparative), the sodium percarbonate used was obtained by using a standard "wet substrate" product obtained with the salting agent chloride (hydration level approx. 100 g / 1000 g) and coating the material in the same way as for When tested with a 50/50 mixture by weight of sodium carbonate and sodium sulfate (coating with 3% total dry weight), the obtained material has an average particle size of about 720 µm. Avox recovered after 6 weeks of storage for the tested products amounted to:

Study 4 43%

Study 5 65%

Study C6 32%

From the above data it appears that in the presence of zeolite / layered silicate, the uncoated percarbonate in Test 4 was significantly more stable than the coated product in Test C6, confirming that by using an appropriate combination of parameters according to the present invention, a product with improved stability over time can be obtained. percarbonate obtained as standard, even of similar particle size after coating. Second, the percarbonate in Study 4 was a particularly suitable basis for post-coating as coating also increased the stability of the percarbonate. Even though the level of coating was the same in Tests 5 and 6, the stability of the coated product, meeting the particle size and hydration level criteria of the composition of the invention, was better than that of the comparative coated product.

Example 7 and Comparison 8

In this example, particle size and hydration level studies were conducted on two samples of sodium percarbonate, which had been produced by reacting between a concentrated solution of hydrogen peroxide and large amounts of sodium carbonate, and by precipitation in the presence of a low concentration of diphosphonic acid stabilizer and crystal habit modifiers in sodium silicate, polyacrylate and pyrophosphate forms, but in the absence of a salting-out agent.

The hydration level test was performed in the same manner as previously described in the present invention.

The obtained results of 14.1 and 10.7 g / kg within 24 hours of storage showed that they are in the accepted range below 30 g / kg. Particle size distribution was obtained by sieving through a set of standard sieves. This showed that the mean particle size was 723 and 747 µm, respectively, and that less than 7% of the particles were below 425 µm. Such a product undergoes a selection process.

In comparison, at C8, the same tests were carried out on a sample of standard commercially available sodium percarbonate obtained using the standard salting-out process. In comparison, 122 g / kg of moisture was captured within 24 hours. The mean particle size was 465 µm. This sample failed the selection process.

The next samples of the example and comparative products were then mixed with the reference detergent in a weight ratio of 15%: 85% and stored in polyethylene-covered boxes in a casing at a constant temperature maintained at 32 ° C and a relative humidity of 80%. The active oxygen content of the composition was measured periodically by a standard titration method and compared to the initial measurements to determine the fraction of retained active oxygen.

Detergent a contained approximately 7.5% sodium linear alkylbenzene sulfate, 25% zeolite A, 4% ethoxylated tallow alcohols, 3% soap, 5% antifoam (SIK), 9% sodium carbonate, 6% sodium sulfate, and some detergent additives gentle containing a proteolytic enzyme, anti-redeposition agents, optical brighteners in small amounts.

Table 2

<td></td><td>Avox stopped after 6 weeks</td>

<td></td><td>Detergent A</td>

<td>Example 7</td><td>66% of the original amount</td>

<td>Comparison 8</td><td>18% of the original amount</td>

Table 2 shows that sodium percarbonate selected according to twin studies showed significantly higher stability.

Another study of other zeolite-containing detergent compositions containing the bleaching activator tetraacetyl ethylenediamine (3%) confirmed that sodium percarbonate selected in accordance with the twin studies retained Avox longer than sodium percarbonate, which did not meet the twin studies.

Example 9 and Comparison 10

In this example, another sample of sodium percarbonate was tested, which was produced by the same general method as that set out in Example 7. The hydration level test resulted in 7.6 g / kg over 24 hours. The particle size was measured as in Example 7. The mean particle size was 716 gm and 10% below 425 (im. Therefore, this sample underwent twinning tests.

Its stability in detergent composition B was tested against the next sodium percarbonate sample presented in comparison 8, in a mixture of 20% sodium percarbonate to 80% of the basic detergent in the same way as in Example 7.

Base detergent B contained approximately 8% linear alkylbenzene sulfate, 3% tallow alcohol ethoxylate, 3% soap, 44% sodium tripolyphosphate, 7% sodium silicate, 20% sodium sulfate and anti-redeposition agent, and low levels of chelates.

Table 3

<td></td><td>Avox stopped after 6 weeks</td>

<td></td><td>Detergent B</td>

<td>Example 9</td><td>72% of the original amount</td>

<td>Comparison 10</td><td>62% of the original amount</td>

It can be seen from Table 3 that the benefit of selecting sodium percarbonate, which actually passes through the twinning tests, is also apparent in the compositions that are formed with the phosphate builder, although the difference is not as significant as with the zeolite compositions.

The next sodium percarbonate sample described in Example 9 was coated with 3 wt.% Sodium carbonate / sodium sulfate (but the weight ratio is 2: 1) as described in Example 5. The resulting product was tested for Avox stability, then tested in reference detergent A, the same conditions as in example 7. It was found that after 6 weeks of storage, 70% of Avox was retained, indicating that the coating further improved the storage quality of the basic sodium percarbonate, which actually underwent twin studies.

Examples 11 to 13

In these examples, the washing compositions were prepared by dry mixing sodium percarbonate obtained by a crystallization process in which sodium percarbonate was precipitated from a solution containing hydrogen peroxide and sodium carbonate in a molar ratio of 0.85: 1 and to which no additional salting agent was added, and the product has heat emission properties after 7-day aging (LKB) &lt;3 (iW / g for 16 hours, hydration level (MPU) 10g / 100Og, MPS (mean particle size) 770 gm (range 1.0), bulk density 16

186 136 wa (BD) 920 g / 1000 g in the previously formed mixture of other ingredients. The ingredients and their respective proportions are given in Table 4 below.

In table 4, ABS stands for sodium olykylbenzton sulphate, oxntene alcohol AEO, other surfactants contain soap and / or cationic parenteral active agents, the bleaching activator is tetpoocetinluetene dimmino or sodium oozornl or oxynbtnatine acetyl complexing agents and one or more acetyl complexing agents, or pulicarbuksnlaoornych, one or more cellulose derivatives, PVP and / or btamodo maleic copolymers acting as anti-redeposition agents, optical brightener, omustine, dye and fragrance, and optional enzymes omylase, prosthesis, lipase, esterase or cellulase.

Table 4

<td rowspan="2">Example</td><td> 11</td><td> 12</td><td> 13</td>

<td colspan="3">Amount in wt.%</td>

<td>Anionic surfactants - ABS</td><td> 9</td><td> 15</td><td> 7</td>

<td>Non-ionic pumitrzchoium active agents - AEO</td><td> 4</td><td> 3</td><td> 3</td>

<td>looe pumitrzchoium active agents</td><td> 9</td><td> 0</td><td> 3</td>

<td>Zeolite 4A</td><td> 28</td><td> 20</td><td> 0</td>

<td>Trójpulifusfurao Na</td><td> 0</td><td> 0</td><td> 37</td>

<td>Coal Na</td><td> 10</td><td> 14</td><td> 0</td>

<td>Sodium percarbonate</td><td> 15</td><td> 20</td><td> 15</td>

<td>Whitening activator</td><td> 0</td><td> 3</td><td> 0</td>

<td>Sodium sulfate</td><td> 6</td><td> 18</td><td> 17</td>

<td>Detergent additives</td><td> 9</td><td> 3</td><td> 8</td>

Similar compositions can be obtained by varying the amounts of the minion ingredients above, within ranges known in the detergent industry that remain effective, and by replacing all or part of the individual ingredients, such as replacing all or part of the ABS with alkyl sulfate, alcohol sulfate, sulfate glyceride, or bursate or phosphate esters. and / or by replacing the AEO with at least partially alkylphenol oxinitrin, PEO / PPO copolymer or fatty acids / amide polyols and / or by replacing SKS6 atolite 4A or with MAP and / or partially by sodium silicate and / or by replacing at least partially sodium cattruphosphate tripolyphosphate and / or by replacing the sodium phosphate solvent with sodium chloride.

The sodium percarbonate incorporated in the composition of each of Examples 11 to 13 sequentially may be changed by using the following percarbonate products (P1 and P2), which were obtained in a crystallizer that operated without a souring agent and which actually meet the parameters of low heat emission, low hydration and acceptable average particle size.

Table 5

<td>Product</td><td>Pl</td><td>P2</td><td>P3</td>

<td>MPU g / 1000 g</td><td> 14</td><td> 1,5</td><td> 9,4</td>

<td>LKB nW / g</td><td> 1</td><td> 2</td><td> 2,3</td>

<td>MPS am</td><td> 680</td><td> 650</td><td> 950</td>

<td>range = (d &lt;&gt; from_lo) / d_in</td><td> 1/0</td><td>oie measured</td><td> 0,9</td>

<td>BD g / 1000g</td><td> 990</td><td>not measured</td><td> 900</td>

<td>Avox%</td><td> 14,7</td><td> 14,9</td><td> 15,0</td>

Range = (d_in-d₁₀ ) / d₅₀ d₉₀ means that 90% of the particles are smaller than d_in, d_l0means that 10% of the particles are smaller than d,₀ id₅₀ means that 50% of the particles are smaller than d50

186 136

Further examples of PCS (P4 to P7) that can be used in place of P2 or P3 products include products prepared in the same equipment under different operating conditions, with no salting agent added continuously, and whose accepted low MPU (&lt;30 g / 100Og) and the low associated 7-day aging LKB &lt;3 nW / g for 16 hours and other physical characteristics are given in Table 6 below.

Table 6

<td>Product</td><td>P4</td><td>P5</td><td>P6</td><td>P7</td>

<td>MPS | im</td><td> 680</td><td> 770</td><td> 840</td><td> 700</td>

<td>range = (4x - d,₀) / d₅₀</td><td> 1/1</td><td> 1,2</td><td> 1,0</td><td> 1,2</td>

<td>BD g / 100Og</td><td> 930</td><td> 920</td><td> 920</td><td> 860</td>

<td>Avox%</td><td> 15,0</td><td> 14,8</td><td> 15,0</td><td> 14,4</td>

The PCS (sodium percarbonate) can then be varied by using those products that are actually accepted as the basis of the coating, for example in an amount of 2 to 5% by weight (especially 3%) of sodium sulphate / carbonate, sodium borate / silicate or coating agents subjected to contacting an acidic acid such as a mixture of boric acid with neutral salts such as sodium sulfate and / or chloride, and optionally, a carboxylic acid and / or a hydroxycarboxylic acid capable of forming a complex with an oxo-boron compound or, in particular, by using mother liquor containing added sodium sulphate with a molar ratio of Most CO: NA₄ from 1: 2 to 2: 1.

The composition will exhibit varying degrees of decomposition of sodium percarbonate, but will benefit from the use of easily stored PCS in large amounts and the stability of its large particle size compared to the use of PCS which has neither one or both of the twin properties of low heat emission and high particle size.

186 136

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