CA2204383A1 - Percarbonate-containing washing, bleaching and cleaning agent composition - Google Patents
Percarbonate-containing washing, bleaching and cleaning agent compositionInfo
- Publication number
- CA2204383A1 CA2204383A1 CA002204383A CA2204383A CA2204383A1 CA 2204383 A1 CA2204383 A1 CA 2204383A1 CA 002204383 A CA002204383 A CA 002204383A CA 2204383 A CA2204383 A CA 2204383A CA 2204383 A1 CA2204383 A1 CA 2204383A1
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- Prior art keywords
- alkali metal
- percarbonate
- coated
- maintenance
- washing
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
- C11D3/39—Organic or inorganic per-compounds
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
- C11D3/39—Organic or inorganic per-compounds
- C11D3/3942—Inorganic per-compounds
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D17/00—Detergent materials or soaps characterised by their shape or physical properties
- C11D17/0039—Coated compositions or coated components in the compositions, (micro)capsules
-
- C—CHEMISTRY; METALLURGY
- C11—ANIMAL OR VEGETABLE OILS, FATS, FATTY SUBSTANCES OR WAXES; FATTY ACIDS THEREFROM; DETERGENTS; CANDLES
- C11D—DETERGENT COMPOSITIONS; USE OF SINGLE SUBSTANCES AS DETERGENTS; SOAP OR SOAP-MAKING; RESIN SOAPS; RECOVERY OF GLYCEROL
- C11D3/00—Other compounding ingredients of detergent compositions covered in group C11D1/00
- C11D3/02—Inorganic compounds ; Elemental compounds
- C11D3/04—Water-soluble compounds
- C11D3/08—Silicates
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- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Wood Science & Technology (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Detergent Compositions (AREA)
Abstract
The invention concerns washing, bleaching and cleaning agent compositions containing coated alkali metal percarbonate, in particular sodium percarbonate, and conventional components of such compositions, including in particular silicate-like builders. Compositions according to the invention, which have good stability during storage yet dissolve rapidly and thus render extension of the washing, bleaching or cleaning period unnecessary, contain an alkali metal percarbonate with an Oa* content in the composition of at least 70 %, a dissolution time of the alkali metal percarbonate in water of less than 10 minutes, determined under specific test conditions in each case, and a morphology index MI greater than 0.03, in particular greater than 0.04, in which: MI = 0.0448 . CV + 3.61 . 106 . d-3; CV = .sigma./d; .sigma. = .SIGMA.(di-d)2.wi/100 and d = .SIGMA.di.wi/100.
Description
' . CA 02204383 1997-0~-02 Percarbonate-contA;n;n~ washing, bleaching and cle~n;n~
agent composition Description The invention relates to a particulate washing, bleaching or cleaning agent composition which contains coated alkali metal percarbonate as bleaching component and conventional constituents of a washing, bleaching or cleaning agent, including in particular silicate builders. The preferably coated sodium percarbonate-containing composition has a high storage stability and a specifically adjustable release of the alkali metal percarbonate. The invention also relates to a process for producing the composition as well as to the alkali metal percarbonate contained herein.
Active oxygen compounds that release hydrogen peroxide when dissolved in water are widely used as bleaching component in washing, bleaching and cleaning agent compositions. The named compositions contain, besides the bleaching component, also framework substances, so-called builders, such as in particular zeolites and layer silicates based on aluminosilicate, and normally one or more surface-active substances (surfactants) as well as constituents from the series of alkaline and/or inorganic electrolytes, bleach activators, such as N-acyl compounds and O-acyl compounds, stabilisers, optical brighteners, foam inhibitors, enzymes, antideposition agents, disinfectants, corrosion inhibitors, aroma substances, dyestuffs, agents to regulate the pH
value and, in the case of cleaning agents, also abrasively acting substances.
Whereas sodium perborate tetrahydrate and sodium perborate monohydrate have been used for a long time as bleaching agents in the named compositions, recently there has been increasing interest in boron-free bleaching components, especially in sodium percarbonate (2 Na2CO3 3 H2O2). On CA 02204383 l997-0~-02 account of the unsatisfactory storage stability of sodium percarbonate in warm-moist conditions, especially in the presence of conventional constituents of washing, bleaching and cleaning agents, silicate builders in particular reducing the storage stability, choosing as stable a sodium percarbonate as possible is of great practical significance. Accordingly, experts in the field are endeavouring to use sodium percarbonate in the named compositions in the form of a product purposively produced so as to be sufficiently stable or in the form of a product stabilised by application of a coating, in order to avoid non-tolerable active oxygen loss (a loss) during storage.
Stabilised sodium percarbonate that can be obtained by applying a coating layer to a sodium percarbonate core is known from many documents: according to DE-OS 24 17 572 and DE-PS 26 22 610 the stabilising coating contains substances from the series sodium carbonate, sodium sulphate and sodium silicate; according to US Patent 4,325,933, sodium percarbonate can be stabilised by using an alkaline earth metal salt, especially magnesium sulphate. Also, boron compounds such as boric acids (DE-PS 28 00 916), borates (DE-OS 33 21 082) and perborates (DE-PS 26 51 442 and DE-PS 28 10 379) are known as sodium percarbonate-coating stabilisers. Finally, the stabilising-acting coating may also contain organic compounds, for example fatty acids (DE-OS 41 09 954) or organic polymers, such as polycarboxylates and cellulose compounds (DE-OS 41 09 953).
CA 02204383 1997-0~-02 The still unpublished German patent application P 43 24 104.2 discloses sodium percarbonate particles with a preferably double-layer coating, a magnesium compound in the first layer and soda as well as alkali metal silicate in the second layer. As the named documents show, a stabilising coating around sodium percarbonate can be produced if sodium percarbonate is contacted with an aqueous solution containing one or more stabilising coating components with sodium percarbonate (sic) and simultaneously or subsequently water is evaporated.
EP-A 0 451 893 discloses a particulate bleaching washing agent composition which contains a zeolite-cont~;n;ng base powder and particulate alkali metal percarbonate, especially sodium percarbonate, the alkali metal percarbonate having a morphology index defined in this document of less than 0.06. The morphology index (MI) couples for grain distributions the mean grain diameter and the standard deviation of the grain distribution according to the formula MI = 0.048 CV + 3.61 106 d-3, the coefficient of variance CV = a/d and a = ~ ~(di-d)2 wi/100 and d = ~di wi/100. According to this document the storage stability of a washing agent cont~;n;ng zeolite and sodium percarbonate is then favourably influenced if a sodium percarbonate with a morphology index of less than 0.06 is added, which corresponds to a product with a mean grain diameter of greater than about 0.4 mm. In this document it is furthermore pointed out that if a sodium percarbonate with a morphology index of less than 0.06, preferably less than 0.04 and in particular less than 0.03 is used, a sufficient storage stability of the washing agent composition is achieved and accordingly the use of an optionally expensive to produce, becomes superfluous.
CA 02204383 1997-0~-02 The inventors of the present application have investigated as regards its storage stability commercially available, uncoated sodium percarbonate with a different morphology index - according to the definition in the EP Application 0 451 893 - admixed with a commercially available washing agent column powder. The a maintenance was measured after 2, 4 and 8 weeks' storage at 30C and 80~ relative humidity, in each case an analogous composition, identical as regards the a content, containing sodium perborate monohydrate instead of sodium percarbonate being tested also for control purposes: within the first four weeks the a maintenance of the compositions decreases in agreement with the mentioned EP document; however, after eight weeks' storage no agreement can be found with the teaching of the mentioned EP document. It was furthermore established that washing agents produced using a sodium percarbonate with a very low morphology index do not have a sufficient long-term ætability - measured in terms of the a maintenance.
Investigations showed that by using coated sodium percarbonate as bleaching component in washing agent compositions, a substantially higher storage stability can be achieved than is possible by choosing an uncoated sodium percarbonate with a low morphology index. Finally, with washing agent compositions containing coated sodium percarbonate practically no dependence on the stability of the morphology index of the coated sodium percarbonate was observed during the first four weeks' storage; only after eight weeks' storage are the expected stability differences, dependent on the morphology index, manifested.
The comparison examples prove the aforedescribed results.
Although washing agent compositions with coated CA 02204383 1997-0~-02 sodium percarbonate as bleaching agent thus have a satisfactory storage stability also under moist-warm storage conditions, they suffer from another disadvantage, namely too long a dissolution time as bleaching component:
in fact, particularly storage-stable products, such as in particular sodium percarbonates produced by fluidised bed spray granulation and then coated, as well as percarbonates with a relatively high proportion of solubility-reducing coating components, for example alkali silicates, have a dissolution time, measured under defined dissolution conditions in water, of far longer than 10 minutes, and in some cases more than 30 minutes. This prolonged dissolution time is undesirable since it necessitates a prolonged wash time.
The object of the present invention is accordingly to provide washing, bleaching and cleaning agents containing coated alkali metal percarbonate that on the one hand have a high storage stability as regards the a maintenance, but on the other hand do not necessitate a prolongation of the washing, bleaching and cleaning time. The coated alkali metal percarbonate contained in the compositions must therefore dissolve in less than 10 minutes. Preferably it should also indicate how the dissolution time of the coated alkali metal percarbonate in the compositions can be reliably adjusted to between about ~ minute to less than 10 minutes.
It was surprisingly found that the morphology index of a coated alkali metal percarbonate that has the desired active oxygen stability in the presence of conventional washing or bleaching components is suitable as a selection criterion for a coated alkali metal percarbonate that dissolves within the desired dissolution time.
CA 02204383 1997-0~-02 The present invention accordingly provides a particulate washing, bleaching or cleaning agent composition containing coated alkali metal percarbonate and conventional washing, bleaching or cleaning agent constituents, especially silicate builders, which is characterised in that the coated alkali metal percarbonate has an alkali metal percarbonate core produced by fluidised bed spray granulation and a single-layer or multi-layer coating of one or more stabilising compounds in an amount of 1 to 15 wt.~, referred to the sodium percarbonate core, the dissolution time of the coated alkali metal percarbonate is less than ten minutes, measured as the dissolution time for 95~ dissolution in water at 15-C and in a concentration of 2 g/l in water, the morphology index MI of the coated alkali metal percarbonate is greater than 0.03, MI being defined by the formula MI = 0.0448 CV + 3.61 106 d-3, the coefficient of variance CV is defined by the formula CV
= a/d, the mean grain size d is defined by the formula d = ~di wi/100, and the standard deviation a is defined by the formula a = ~ ~(di-d)2 wi/100, wherein di denotes the mean particle size (arithmetic mean of two screenings) of the grain size fraction i and wi denotes the weight proportion of this fraction, and the fractions from the screening are obtained using screens of about 0.1 mm gradation ranging from 0.1 to 0.8 mm and a 1.0 mm screen and the a* maintenance in a washing agent composition cont~;n;ng silicate builders is at least 70~ after 8 weeks' storage at 30 C and 80~ relative humidity, the a*
maintenance being the ratio, expressed in per cent, of the a maintenance of the composition to the a maintenance of a composition of identical a and stored in the same way, with sodium perborate monohydrate instead of the coated sodium percarbonate.
CA 02204383 1997-0~-02 6a With a sufficient coating of an alkali metal percarbonate, its storage stability (a maintenance) in a washing agent composition practically no longer depPn~en~s on the morphology index; however, with decreasing morphology index within the claimed range the dissolution time of the coated alkali metal percarbonate increases significantly. By choosing a sufficiently storage-stable coated alkali metal percarbonate with a specific morphology index it is possible to produce compositions according to the claims in which the coated alkali metal percarbonate within the desired time (sic).
CA 02204383 l997-0~-02 , . .
,~1 Preferred compositions contain coated alkali metal percarbonates whose core has been produced by fluidised bed spray granulation. With fluidised bed spray granules particular attention is paid to the teaching according to the invention, whereby a percarbonate with an MI of greater than 0.03 should be chosen in order to maintain a sufficiently short dissolution time. It is convenient to choose the conditions already during the production of the alkali metal percarbonate core by fluidised bed spray granulation, so as to produce an MI
value of greater than 0.03.
Fig. 1/1 shows the relationship between the dissolution time of the coated sodium percarbonate investigated by way of example, and the morphology index: at a morphology index in the range around 0.03 to 0.04, the curves exhibit an inflection point. Compositions according to the invention contain preferably coated sodium percarbonate of the formula 2 Na2CO3 3 H22 with a morphology index of greater than 0.04; compositions with a very short CA 02204383 l997-0~-02 dissolution time contain a coated alkali metal percarbonate with a morphology index of greater than 0.06.
Washing, bleaching or cleaning agent compositions according to the invention contain coated alkali metal percarbonate, preferably coated sodium percarbonate. Sodium percarbonate particles having a stabilising coating are known from numerous documents - reference is made by way of example to the documents mentioned in the introduction. Preferred coated sodium percarbonate particles that can be used according to the invention have a core of sodium percarbonate and a coating of one or more compounds in anhydrous or hydrated form from the series soda, sodium bicarbonate, alkali and alkaline earth metal salts of mineral acids, especially sodium and magnesium sulphate, alkali metal and alkaline earth metal silicates, alkali metal borates and perborates. A particularly effective coating that leads to a high storage stability, i.e. to a low loss of active oxygen during storage of the coated sodium percarbonate in the presence of washing agent constituents, is based on a combination of soda, sodium sulphate and water glass or a combination of magnesium sulphate, soda and water glass, wherein the named substances may be arranged in one or in several layers.
The amount of coating is governed by the desired stabilising effect: with increasing amount of coating the storage stability increases, but on the other hand the water solubility decreases, especially when the coating contains alkali metal silicate. Since the active oxygen content of the coated product decreases through the amount of coating on the sodium percarbonate core, the amount of coating is generally below 25 wt.~ referred to the sodium percarbonate core, preferably below 15 wt.~. Although an amount of coating of less than 1 wt.~ can already lead to a marked increase in stability, the coated sodium percarbonate particles to be used according to the invention preferably contain an amount of coating of at least 1 wt.~, referred to the sodium percarbonate core. In CA 02204383 l997-0~-02 ~q order on the one hand to take into account the storage stability reqiremenerts, and on the other hand to be able to use a product with as high an active oxygen content as possible in the washing, bleaching and cleaning agent compositions, the amount of coating is preferably 2 to 12 wt.~, particularly preferably 3 to 8 wt.~, referred to the sodium percarbonate core.
The dissolution time defined according to the claim specifies the time within which 95~ of the coated alkali metal percarbonate at a concentration of 2 g/l has dissolved in water at 15C, the solution being stirred during the investigation. The measurement is conveniently performed conductometrically.
An essential quality criterion for a washing, bleaching as well as cleaning agent composition that contains an active oxygen compound as bleaching agent is its storage stability. The storage stability of the bleaching component, in this case therefore of the coated alkali metal percarbonate, is influenced to a considerable extent by the conventional constituents contained in these compositions; silicate builders such as zeolites and layer silicates based on aluminosilicate have a particularly stability-reducing effect. Accordingly the storage stability of the composition is measured by the active oxygen maintenance (a maintenance) after 8 weeks' storage at 30C and 80~ relative humidity. For a quality comparison it has proved convenient to sub~ect in each case a similar composition to the storage test, in parallel to the storage of compositions according to the invention, the similar composition differing from the composition according to the invention only in that it contains sodium perborate monohydrate instead of the coated alkali metal percarbonate, and moreover in an amount that yields the same active oxygen content. Washing, bleaching and cleaning agents containing sodium perborate monohydrate exhibit a storage stability that is perfectly adequate for CA 02204383 l997-0~-02 practical purposes, so that the stability of a composition according to the invention can be compared to that of a similar composition containing a sodium perborate monohydrate: the a* maintenance according to the claim is accordingly the ratio, expressed in per cent, of the a maintenance of the composition according to the invention to the a maintenance of the similar composition containing sodium perborate monohydrate. Compositions according to the claims have an a* maintenance of at least 70~, preferably at least 80~, and particularly preferably at least 90~.
The washing, bleaching and cleaning agent compositions according to the invention contain, besides a coated alkali metal percarbonate, conventional washing, bleaching or cleaning agent constituents, as have already been mentioned at the beginning. A main constituent of the compositions are surface-active agents from the series of cationic, anionic, non-ionic, amphoteric and ampholytic surface-active agents. A further main component are the alreadymentioned builders, aluminosilicate washing agent builders from the series of zeolites, layer silicates or disilicates being preferred; further builders are for example polyphosphates, amino polyacetic acids and amino polyphosphonic acids, polyhydroxy carboxylic acids, as well as biologically degradable polymers, preferably those based on renewable raw materials. Phosphate-containing builders are less preferred nowadays. The compositions frequently also contain alkaline and inorganic electrolytes, for example alkanolamines and silicates, carbonates and sulphates. Compositions that are intended to wash, bleach or clean effectively at low temperatures in addition contain bleach activators, for example those from the series of N-acyl compounds and O-acyl compounds, such as tetracetyl ethylenediamine (TAED) and nonanoyl hydroxybenzene sulphonate (NOBS).
CA 02204383 l997-0~-02 ~ ' I
A washing and bleaching agent composition according to the invention is formulated roughly as follows: 5 to 30 wt.~, preferably 10 to 25 wt.~, of anionic and/or non-ionic surfactants; 5 to 70 wt.~, preferably 20 to 50 wt.%, of silicate washing agent builders; O to 20 wt.~, preferably 1 to 8 wt.~, of organic builders; 2 to 35 wt.~, preferably 10 to 25 wt.~, of coated alkali metal percarbonate; O. 3 to 20 wt.~, preferably 1 to 10 wt.~, of bleach activators, and in addition alkaline and inorganic electrolytes, if required enzymes, and conventional auxiliaries as well as water.
Pure bleaching agents, such as may be used as additives for bleach-free washing agents, normally contain 5 to 95 wt.~, especially 15 to 70 wt.~, of coated alkali metal percarbonate; 2 to 50 wt.~, especially 5 to 25 wt.~, of bleach activator; O to 40 wt.~ of pH-regulating agents, and in addition conventional auxiliaries and water. Cleaning agents according to the invention generally contain surfactants, builders, coated alkali metal percarbonate, and activators; scouring cleaning agents contain in addition abrasive constituents.
Washing, bleaching and cleaning agent compositions according to the invention can be prepared by homogeneous m;~;ng of coated alkali metal percarbonate with conventional washing, bleaching and/or cleaning agent constituents, which may be present individually or in already premixed form. The premixed form is conveniently a spray-dried product that already contains essential constituents of the composition; in order to produce a washing agent composition on the other hand, a bleach-free washing agent column powder produced by spray drying or agglomerative granulation is suitable. The process according to the invention is characterised in that a particulate, coated alkali metal percarbonate is used having a morphology index of greater than 0. 03, a dissolution time of less than 10 minutes, and an active CA 02204383 l997-0~-02 , ~(Z
oxygen stability corresponding to an a* maintenance of the composition of at least 70~, preferably more than 80~ and in particular more than 90~, measured after 8 weeks' storage at 30C and 80~ relative humidity, the morphology index, dissolution time and the a* maintenance being defined as discussed hereinbefore. Besides homogenous mixing, the production procèss can also comprise further conventional process steps, such as a granulation or bead formation of the homogeneously mixed composition, for example by means of the known compression agglomeration or extrusion. The coated alkali metal percarbonate to be used in the production preferably has a morphology index of greater than 0.04 and in particular greater than 0.06.
The invention also provides a coated alkali metal percarbonate with a morphology index of greater than 0.03 and a dissolution time of less than 10 minutes and an a* maintenance in a washing agent composition containing a silicate builder of at least 70~ after 8 weeks storage at 30C and 80~ relative humidity, the morphology index, the dissolution time and the a* maintenance being defined as described hereinbefore, for use in washing, bleaching and cleaning agent compositions. A coated alkali metal percarbonate, such as in particular coated sodium percarbonate, having the aforementioned properties can be obtained by coating in a manner known per se an alkali metal percarbonate, preferably an alkali metal percarbonate produced by fluidised bed spray granulation, with a lower morphology index than that of the product to be produced, for example by spraying solutions containing one or more coating components on to this alkali metal percarbonate in a fluidised bed and evaporating the water. Alternatively, an already coated alkali metal percarbonate with the desired sufficient active oxygen stability, though with a smaller morphology index and thus a longer dissolution time compared to the required data of the product to be produced, can be obtained by fractionation by means of CA 02204383 l997-0~-02 ,~ l3 screening. The preferred coated sodium percarbonate is substantially phosphorus-free and chloride-free.
As already mentioned, the washing, bleaching and cleaning agent compositions according to the invention with a high active oxygen stability have a dissolution time of less than 10 minutes. It is a particular advantage of the compositions according to the invention that the dissolution time of the coated alkali metal percarbonate contained therein can be specifically adjusted by adopting the morphology index as a selection criterion. Control of the release of the alkali metal percarbonate is then in particular of interest if the composition contains oxidation-sensitive enzymes: in such cases it is desirable that the enzymes can fully exert their action within the first few minutes during the washing, bleaching or cleaning, before the dissolving alkali metal percarbonate releases hydrogen peroxide and inhibits the action of the enzymes by oxidation. By selecting the morphology index the desired dissolution time can thus be adjusted within the range of less than 10 minutes.
By virtue of the possible short dissolution time according to the invention of the alkali metal percarbonate of less than 10 minutes and in particular less than 4 minutes in the compositions according to the invention, an extension of the washing, bleaching and cleaning duration can be avoided with respect to compositions that contain sodium perborate monohydrate instead of an alkali metal percarbonate, without having to accept a poorer storage stability.
The invention is illustrated in more detail on the basis of the following examples and comparison examples.
CA 02204383 l997-0~-02 ~1~
Examples a) Determination of the storage stability in washing agent mixtures:
A phosphate-free but zeolite-containing washing powder, TAED activator and a coated or uncoated sodium percarbonate (NaPc), or sodium perborate monohydrate (Pbmh) as standard and reference bleaching agents respectively, are mixed in amounts such that the mixture contains 5~ TAED and the a content is about 2.35 wt.~. Constituents in the washing powder in wt.~:
Anionic surfactants 12 Non-ionic surfactants 8 Zeolite A 36 Soda 10 Na silicates 3 Remainder, including moisture 31.
800 g of the relevant mixture are stored in commercially available, water-repellent impregnated and sealed E1 washing agent packets at 30C and 80 relative humidity in a climatically controlled cabinet. A packet is stored per withdrawal period -after 2, 4 and 8 weeks. The a content is determined in a conventional way using permanganate; the relevant a maintenance is calculated in per cent from the initial a content and the a content after 2, 4 and 8 weeks. The a* maintenance referred to the standard is calculated according to the formula:
Oa-maintenance~NaPc) a* maintenance = . .100. The a Oa-malntenance(Pbmh) maintenance of the standard with PbmH was in the range between 89 and 93~ in all examples and comparison examples.
CA 02204383 l997-0~-02 lA~5 b) Determination of the dissolution time:
2 g of coated sodium percarbonate are stirred in 1 l of water of (sic) 15C; the dissolution time is defined as the time at which 95~ has dissolved; the determination is performed conductometrically.
c) Determination of the morphology index (MI):
The product to be determined is screened using screens of nominal values (mm) 0.1; 0.2; 0.3; 0.4; 0.5; 0.6;
0.71; 0.8 and 1.0 and, as necessary (comparison examples), in addition 1.25 and 1.4 mm. The fractions are weighed and the MI is determined therefrom according to the formula.
d) Un-coated sodium percarbonate was, unless otherwise specified, produced according to DE Patent Application P 43 29 205.4 by fluidised bed spray granulation, an aqueous hydrogen peroxide solution and an aqueous sodium carbonate solution which does not contain phosphorus-containing crystallisation inhibitors being sprayed by means of a triple-substance atomiser nozzle with an extended central pipe and external mixing of the solutions in a fluidised bed that contains seeds whose dimensions are less than that of the granulate particles to be produced, and water simultaneously being evaporated at a fluidised bed temperature in the range from 40 to 95.
Unless the desired morphology index is obtained directly by the choice of the operating parameters, desired products are obtained by fractionation (screening).
CA 02204383 l997-0~-02 e) Coated sodium percarbonate:
In a fluidised bed dryer the aqueous solutions containing the coating components are sprayed in succession on to a fluidised bed composed of the sodium percarbonate (NaPc) to be coated, employing the drying air (air inlet temperature 100 to 110C) -first of all an MgSO4 solution (20 wt.~ MgSO4), followed by a combined Na2CO3/sodium silicate solution (20 wt.~ Na2CO3, 8 wt.% sodium silicate (SiO2 : Na20 approx. 3.5 : 1)). The temperature of the fluidised bed is maintained in the range from 50 to 60C, post-drying being carried out at 80 to 90C. The solutions are sprayed using conventional twin-substance nozzles with air as blowing agent.
Comparison examples VB1 and VB2 Uncoated, commercially available sodium percarbonate, produced by a crystallisation process, with different morphology index MI, was tested with regard to the a maintenance during storage. The results of the a maintenance are shown in Table 1.
T~hle 1 a maintenance (~) VBl a b c d MI 0.022 0.033 0.053 0.063 Start 100 100 100 100 2 Wo. 62 59 52 48 4 Wo. 40 35 31 29 8 Wo. 13 10 19 19 Wo. = Storage duration in weeks at 30C and 80~ relative humidity CA 02204383 l997-0~-02 :' The storage time stability of the uncoated sodium percarbonate is insufficient, irrespective of the MI.
Coated sodium percarbonate - commercially available sodium percarbonate produced by crystallisation and stabilised with 4 wt.~ MgSO4, 4 wt.~ soda and 1.6 wt.~ water glass -was tested as regards the a maintenance. The results are given in Table 2.
T~hle 2 VB2 a b c d MI 0.023 0.034 0.052 0.063 Start 100 100 100 100 2 Wo. 89 86 87 86 4 Wo. 78 73 73 72 8 Wo. 57 49 46 42 The influence of the MI on the a maintenance is hardly detectable to start with, but after 8 weeks clear differences are found.
Examples 1 to 3 Sodium percarbonate (NaPc), produced according to the general procedure in paragraph d), was coated according to paragraph e). The weight ratio of MgSO4 to soda to sodium silicate was always 5 to 5 to 2. The Tables 3, 4 and 5 show the results of the determination of the MI-, dissolution time, bulk density (Sd), initial a value, a maintenance after 8 weeks' storage at 30C and 80~ relative humidity, as well as the screening analysis. The dissolution time decreases with increasing MI without the a maintenance being reduced.
CA 02204383 l997-05-02 ~1~
In Example 1 the total amount of coating was 12~, in Example 2 6~, and in Example 3 4~, in each case referred to the sodium percarbonate core.
Table 3: NaPc with 12~ stabilising material ScrPen an-lysis, portior in % ~n scr~en in mm No. MI Dissol- Sd Oa Oa 1.4 1.25 1.0 0.8 0.71 0.6 0.5 0.4 0.3 0.2 0.1 0 ution g/l X maintenance time after 8 weeks, in X
min 1-1 0.014 34 980 11.3 91 0 0 15 56 7 14 6 2 0 0 0 0 *) 1-2 0.017 34 960 11.4 92 0 0 0 20 31 37 8 3 1 0 0 0 D
*) o 1-3 0.026 32 990 11 . 4 93 0 0 0 1 1 6 82 10 0 0 0 0 * ) r 1-4 0.036 29 1000 11 . 6 90 0 0 3 11 8 20 19 16 14 8 1 0 ~ ~
* ) ~o ~
1-5 0.036 22 1020 12.1 91 0 0 0 2 7 25 36 26 3 1 0 0 *) O
1-6 0.048 7.2 1070 11 . 3 91 0 0 0 0 0 0 19 59 19 3 0 0 O
1-7 0.051 6.2 1060 11.4 9O - - 0 0 5 10 22 31 20 9 2 1-8 0.064 2.5 1050 11 . 6 88 - - 0 0 2 8 15 30 25 15 5 0 1-9 0.075 2.0 1060 11.3 87 - - - - - 5 15 25 30 20 5 0 Table 4: NaPc with 6~ stabilising material Scr~en analysis, portion in % on screen in mm No. MI Dissol- Sd Oa Oa 1.4 1.25 1.0 0.8 0.71 0.6 0.5 0.4 0.3 0.2 0.1 0 ution g/l % maintenance time after 8 min weeks, in %
2-1 0.015 11 1000 11.9 88 0 0 3 66 6 12 7 4 2 0 0 0 *) 2-2 0.024 10.5 930 13.4 87 - 4 6 16 10 26 27 10 1 0 0 0 *) 2-3 0.030 8.6 1110 13.0 86 0 0 1 3 6 32 32 18 6 1 1 0 D
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agent composition Description The invention relates to a particulate washing, bleaching or cleaning agent composition which contains coated alkali metal percarbonate as bleaching component and conventional constituents of a washing, bleaching or cleaning agent, including in particular silicate builders. The preferably coated sodium percarbonate-containing composition has a high storage stability and a specifically adjustable release of the alkali metal percarbonate. The invention also relates to a process for producing the composition as well as to the alkali metal percarbonate contained herein.
Active oxygen compounds that release hydrogen peroxide when dissolved in water are widely used as bleaching component in washing, bleaching and cleaning agent compositions. The named compositions contain, besides the bleaching component, also framework substances, so-called builders, such as in particular zeolites and layer silicates based on aluminosilicate, and normally one or more surface-active substances (surfactants) as well as constituents from the series of alkaline and/or inorganic electrolytes, bleach activators, such as N-acyl compounds and O-acyl compounds, stabilisers, optical brighteners, foam inhibitors, enzymes, antideposition agents, disinfectants, corrosion inhibitors, aroma substances, dyestuffs, agents to regulate the pH
value and, in the case of cleaning agents, also abrasively acting substances.
Whereas sodium perborate tetrahydrate and sodium perborate monohydrate have been used for a long time as bleaching agents in the named compositions, recently there has been increasing interest in boron-free bleaching components, especially in sodium percarbonate (2 Na2CO3 3 H2O2). On CA 02204383 l997-0~-02 account of the unsatisfactory storage stability of sodium percarbonate in warm-moist conditions, especially in the presence of conventional constituents of washing, bleaching and cleaning agents, silicate builders in particular reducing the storage stability, choosing as stable a sodium percarbonate as possible is of great practical significance. Accordingly, experts in the field are endeavouring to use sodium percarbonate in the named compositions in the form of a product purposively produced so as to be sufficiently stable or in the form of a product stabilised by application of a coating, in order to avoid non-tolerable active oxygen loss (a loss) during storage.
Stabilised sodium percarbonate that can be obtained by applying a coating layer to a sodium percarbonate core is known from many documents: according to DE-OS 24 17 572 and DE-PS 26 22 610 the stabilising coating contains substances from the series sodium carbonate, sodium sulphate and sodium silicate; according to US Patent 4,325,933, sodium percarbonate can be stabilised by using an alkaline earth metal salt, especially magnesium sulphate. Also, boron compounds such as boric acids (DE-PS 28 00 916), borates (DE-OS 33 21 082) and perborates (DE-PS 26 51 442 and DE-PS 28 10 379) are known as sodium percarbonate-coating stabilisers. Finally, the stabilising-acting coating may also contain organic compounds, for example fatty acids (DE-OS 41 09 954) or organic polymers, such as polycarboxylates and cellulose compounds (DE-OS 41 09 953).
CA 02204383 1997-0~-02 The still unpublished German patent application P 43 24 104.2 discloses sodium percarbonate particles with a preferably double-layer coating, a magnesium compound in the first layer and soda as well as alkali metal silicate in the second layer. As the named documents show, a stabilising coating around sodium percarbonate can be produced if sodium percarbonate is contacted with an aqueous solution containing one or more stabilising coating components with sodium percarbonate (sic) and simultaneously or subsequently water is evaporated.
EP-A 0 451 893 discloses a particulate bleaching washing agent composition which contains a zeolite-cont~;n;ng base powder and particulate alkali metal percarbonate, especially sodium percarbonate, the alkali metal percarbonate having a morphology index defined in this document of less than 0.06. The morphology index (MI) couples for grain distributions the mean grain diameter and the standard deviation of the grain distribution according to the formula MI = 0.048 CV + 3.61 106 d-3, the coefficient of variance CV = a/d and a = ~ ~(di-d)2 wi/100 and d = ~di wi/100. According to this document the storage stability of a washing agent cont~;n;ng zeolite and sodium percarbonate is then favourably influenced if a sodium percarbonate with a morphology index of less than 0.06 is added, which corresponds to a product with a mean grain diameter of greater than about 0.4 mm. In this document it is furthermore pointed out that if a sodium percarbonate with a morphology index of less than 0.06, preferably less than 0.04 and in particular less than 0.03 is used, a sufficient storage stability of the washing agent composition is achieved and accordingly the use of an optionally expensive to produce, becomes superfluous.
CA 02204383 1997-0~-02 The inventors of the present application have investigated as regards its storage stability commercially available, uncoated sodium percarbonate with a different morphology index - according to the definition in the EP Application 0 451 893 - admixed with a commercially available washing agent column powder. The a maintenance was measured after 2, 4 and 8 weeks' storage at 30C and 80~ relative humidity, in each case an analogous composition, identical as regards the a content, containing sodium perborate monohydrate instead of sodium percarbonate being tested also for control purposes: within the first four weeks the a maintenance of the compositions decreases in agreement with the mentioned EP document; however, after eight weeks' storage no agreement can be found with the teaching of the mentioned EP document. It was furthermore established that washing agents produced using a sodium percarbonate with a very low morphology index do not have a sufficient long-term ætability - measured in terms of the a maintenance.
Investigations showed that by using coated sodium percarbonate as bleaching component in washing agent compositions, a substantially higher storage stability can be achieved than is possible by choosing an uncoated sodium percarbonate with a low morphology index. Finally, with washing agent compositions containing coated sodium percarbonate practically no dependence on the stability of the morphology index of the coated sodium percarbonate was observed during the first four weeks' storage; only after eight weeks' storage are the expected stability differences, dependent on the morphology index, manifested.
The comparison examples prove the aforedescribed results.
Although washing agent compositions with coated CA 02204383 1997-0~-02 sodium percarbonate as bleaching agent thus have a satisfactory storage stability also under moist-warm storage conditions, they suffer from another disadvantage, namely too long a dissolution time as bleaching component:
in fact, particularly storage-stable products, such as in particular sodium percarbonates produced by fluidised bed spray granulation and then coated, as well as percarbonates with a relatively high proportion of solubility-reducing coating components, for example alkali silicates, have a dissolution time, measured under defined dissolution conditions in water, of far longer than 10 minutes, and in some cases more than 30 minutes. This prolonged dissolution time is undesirable since it necessitates a prolonged wash time.
The object of the present invention is accordingly to provide washing, bleaching and cleaning agents containing coated alkali metal percarbonate that on the one hand have a high storage stability as regards the a maintenance, but on the other hand do not necessitate a prolongation of the washing, bleaching and cleaning time. The coated alkali metal percarbonate contained in the compositions must therefore dissolve in less than 10 minutes. Preferably it should also indicate how the dissolution time of the coated alkali metal percarbonate in the compositions can be reliably adjusted to between about ~ minute to less than 10 minutes.
It was surprisingly found that the morphology index of a coated alkali metal percarbonate that has the desired active oxygen stability in the presence of conventional washing or bleaching components is suitable as a selection criterion for a coated alkali metal percarbonate that dissolves within the desired dissolution time.
CA 02204383 1997-0~-02 The present invention accordingly provides a particulate washing, bleaching or cleaning agent composition containing coated alkali metal percarbonate and conventional washing, bleaching or cleaning agent constituents, especially silicate builders, which is characterised in that the coated alkali metal percarbonate has an alkali metal percarbonate core produced by fluidised bed spray granulation and a single-layer or multi-layer coating of one or more stabilising compounds in an amount of 1 to 15 wt.~, referred to the sodium percarbonate core, the dissolution time of the coated alkali metal percarbonate is less than ten minutes, measured as the dissolution time for 95~ dissolution in water at 15-C and in a concentration of 2 g/l in water, the morphology index MI of the coated alkali metal percarbonate is greater than 0.03, MI being defined by the formula MI = 0.0448 CV + 3.61 106 d-3, the coefficient of variance CV is defined by the formula CV
= a/d, the mean grain size d is defined by the formula d = ~di wi/100, and the standard deviation a is defined by the formula a = ~ ~(di-d)2 wi/100, wherein di denotes the mean particle size (arithmetic mean of two screenings) of the grain size fraction i and wi denotes the weight proportion of this fraction, and the fractions from the screening are obtained using screens of about 0.1 mm gradation ranging from 0.1 to 0.8 mm and a 1.0 mm screen and the a* maintenance in a washing agent composition cont~;n;ng silicate builders is at least 70~ after 8 weeks' storage at 30 C and 80~ relative humidity, the a*
maintenance being the ratio, expressed in per cent, of the a maintenance of the composition to the a maintenance of a composition of identical a and stored in the same way, with sodium perborate monohydrate instead of the coated sodium percarbonate.
CA 02204383 1997-0~-02 6a With a sufficient coating of an alkali metal percarbonate, its storage stability (a maintenance) in a washing agent composition practically no longer depPn~en~s on the morphology index; however, with decreasing morphology index within the claimed range the dissolution time of the coated alkali metal percarbonate increases significantly. By choosing a sufficiently storage-stable coated alkali metal percarbonate with a specific morphology index it is possible to produce compositions according to the claims in which the coated alkali metal percarbonate within the desired time (sic).
CA 02204383 l997-0~-02 , . .
,~1 Preferred compositions contain coated alkali metal percarbonates whose core has been produced by fluidised bed spray granulation. With fluidised bed spray granules particular attention is paid to the teaching according to the invention, whereby a percarbonate with an MI of greater than 0.03 should be chosen in order to maintain a sufficiently short dissolution time. It is convenient to choose the conditions already during the production of the alkali metal percarbonate core by fluidised bed spray granulation, so as to produce an MI
value of greater than 0.03.
Fig. 1/1 shows the relationship between the dissolution time of the coated sodium percarbonate investigated by way of example, and the morphology index: at a morphology index in the range around 0.03 to 0.04, the curves exhibit an inflection point. Compositions according to the invention contain preferably coated sodium percarbonate of the formula 2 Na2CO3 3 H22 with a morphology index of greater than 0.04; compositions with a very short CA 02204383 l997-0~-02 dissolution time contain a coated alkali metal percarbonate with a morphology index of greater than 0.06.
Washing, bleaching or cleaning agent compositions according to the invention contain coated alkali metal percarbonate, preferably coated sodium percarbonate. Sodium percarbonate particles having a stabilising coating are known from numerous documents - reference is made by way of example to the documents mentioned in the introduction. Preferred coated sodium percarbonate particles that can be used according to the invention have a core of sodium percarbonate and a coating of one or more compounds in anhydrous or hydrated form from the series soda, sodium bicarbonate, alkali and alkaline earth metal salts of mineral acids, especially sodium and magnesium sulphate, alkali metal and alkaline earth metal silicates, alkali metal borates and perborates. A particularly effective coating that leads to a high storage stability, i.e. to a low loss of active oxygen during storage of the coated sodium percarbonate in the presence of washing agent constituents, is based on a combination of soda, sodium sulphate and water glass or a combination of magnesium sulphate, soda and water glass, wherein the named substances may be arranged in one or in several layers.
The amount of coating is governed by the desired stabilising effect: with increasing amount of coating the storage stability increases, but on the other hand the water solubility decreases, especially when the coating contains alkali metal silicate. Since the active oxygen content of the coated product decreases through the amount of coating on the sodium percarbonate core, the amount of coating is generally below 25 wt.~ referred to the sodium percarbonate core, preferably below 15 wt.~. Although an amount of coating of less than 1 wt.~ can already lead to a marked increase in stability, the coated sodium percarbonate particles to be used according to the invention preferably contain an amount of coating of at least 1 wt.~, referred to the sodium percarbonate core. In CA 02204383 l997-0~-02 ~q order on the one hand to take into account the storage stability reqiremenerts, and on the other hand to be able to use a product with as high an active oxygen content as possible in the washing, bleaching and cleaning agent compositions, the amount of coating is preferably 2 to 12 wt.~, particularly preferably 3 to 8 wt.~, referred to the sodium percarbonate core.
The dissolution time defined according to the claim specifies the time within which 95~ of the coated alkali metal percarbonate at a concentration of 2 g/l has dissolved in water at 15C, the solution being stirred during the investigation. The measurement is conveniently performed conductometrically.
An essential quality criterion for a washing, bleaching as well as cleaning agent composition that contains an active oxygen compound as bleaching agent is its storage stability. The storage stability of the bleaching component, in this case therefore of the coated alkali metal percarbonate, is influenced to a considerable extent by the conventional constituents contained in these compositions; silicate builders such as zeolites and layer silicates based on aluminosilicate have a particularly stability-reducing effect. Accordingly the storage stability of the composition is measured by the active oxygen maintenance (a maintenance) after 8 weeks' storage at 30C and 80~ relative humidity. For a quality comparison it has proved convenient to sub~ect in each case a similar composition to the storage test, in parallel to the storage of compositions according to the invention, the similar composition differing from the composition according to the invention only in that it contains sodium perborate monohydrate instead of the coated alkali metal percarbonate, and moreover in an amount that yields the same active oxygen content. Washing, bleaching and cleaning agents containing sodium perborate monohydrate exhibit a storage stability that is perfectly adequate for CA 02204383 l997-0~-02 practical purposes, so that the stability of a composition according to the invention can be compared to that of a similar composition containing a sodium perborate monohydrate: the a* maintenance according to the claim is accordingly the ratio, expressed in per cent, of the a maintenance of the composition according to the invention to the a maintenance of the similar composition containing sodium perborate monohydrate. Compositions according to the claims have an a* maintenance of at least 70~, preferably at least 80~, and particularly preferably at least 90~.
The washing, bleaching and cleaning agent compositions according to the invention contain, besides a coated alkali metal percarbonate, conventional washing, bleaching or cleaning agent constituents, as have already been mentioned at the beginning. A main constituent of the compositions are surface-active agents from the series of cationic, anionic, non-ionic, amphoteric and ampholytic surface-active agents. A further main component are the alreadymentioned builders, aluminosilicate washing agent builders from the series of zeolites, layer silicates or disilicates being preferred; further builders are for example polyphosphates, amino polyacetic acids and amino polyphosphonic acids, polyhydroxy carboxylic acids, as well as biologically degradable polymers, preferably those based on renewable raw materials. Phosphate-containing builders are less preferred nowadays. The compositions frequently also contain alkaline and inorganic electrolytes, for example alkanolamines and silicates, carbonates and sulphates. Compositions that are intended to wash, bleach or clean effectively at low temperatures in addition contain bleach activators, for example those from the series of N-acyl compounds and O-acyl compounds, such as tetracetyl ethylenediamine (TAED) and nonanoyl hydroxybenzene sulphonate (NOBS).
CA 02204383 l997-0~-02 ~ ' I
A washing and bleaching agent composition according to the invention is formulated roughly as follows: 5 to 30 wt.~, preferably 10 to 25 wt.~, of anionic and/or non-ionic surfactants; 5 to 70 wt.~, preferably 20 to 50 wt.%, of silicate washing agent builders; O to 20 wt.~, preferably 1 to 8 wt.~, of organic builders; 2 to 35 wt.~, preferably 10 to 25 wt.~, of coated alkali metal percarbonate; O. 3 to 20 wt.~, preferably 1 to 10 wt.~, of bleach activators, and in addition alkaline and inorganic electrolytes, if required enzymes, and conventional auxiliaries as well as water.
Pure bleaching agents, such as may be used as additives for bleach-free washing agents, normally contain 5 to 95 wt.~, especially 15 to 70 wt.~, of coated alkali metal percarbonate; 2 to 50 wt.~, especially 5 to 25 wt.~, of bleach activator; O to 40 wt.~ of pH-regulating agents, and in addition conventional auxiliaries and water. Cleaning agents according to the invention generally contain surfactants, builders, coated alkali metal percarbonate, and activators; scouring cleaning agents contain in addition abrasive constituents.
Washing, bleaching and cleaning agent compositions according to the invention can be prepared by homogeneous m;~;ng of coated alkali metal percarbonate with conventional washing, bleaching and/or cleaning agent constituents, which may be present individually or in already premixed form. The premixed form is conveniently a spray-dried product that already contains essential constituents of the composition; in order to produce a washing agent composition on the other hand, a bleach-free washing agent column powder produced by spray drying or agglomerative granulation is suitable. The process according to the invention is characterised in that a particulate, coated alkali metal percarbonate is used having a morphology index of greater than 0. 03, a dissolution time of less than 10 minutes, and an active CA 02204383 l997-0~-02 , ~(Z
oxygen stability corresponding to an a* maintenance of the composition of at least 70~, preferably more than 80~ and in particular more than 90~, measured after 8 weeks' storage at 30C and 80~ relative humidity, the morphology index, dissolution time and the a* maintenance being defined as discussed hereinbefore. Besides homogenous mixing, the production procèss can also comprise further conventional process steps, such as a granulation or bead formation of the homogeneously mixed composition, for example by means of the known compression agglomeration or extrusion. The coated alkali metal percarbonate to be used in the production preferably has a morphology index of greater than 0.04 and in particular greater than 0.06.
The invention also provides a coated alkali metal percarbonate with a morphology index of greater than 0.03 and a dissolution time of less than 10 minutes and an a* maintenance in a washing agent composition containing a silicate builder of at least 70~ after 8 weeks storage at 30C and 80~ relative humidity, the morphology index, the dissolution time and the a* maintenance being defined as described hereinbefore, for use in washing, bleaching and cleaning agent compositions. A coated alkali metal percarbonate, such as in particular coated sodium percarbonate, having the aforementioned properties can be obtained by coating in a manner known per se an alkali metal percarbonate, preferably an alkali metal percarbonate produced by fluidised bed spray granulation, with a lower morphology index than that of the product to be produced, for example by spraying solutions containing one or more coating components on to this alkali metal percarbonate in a fluidised bed and evaporating the water. Alternatively, an already coated alkali metal percarbonate with the desired sufficient active oxygen stability, though with a smaller morphology index and thus a longer dissolution time compared to the required data of the product to be produced, can be obtained by fractionation by means of CA 02204383 l997-0~-02 ,~ l3 screening. The preferred coated sodium percarbonate is substantially phosphorus-free and chloride-free.
As already mentioned, the washing, bleaching and cleaning agent compositions according to the invention with a high active oxygen stability have a dissolution time of less than 10 minutes. It is a particular advantage of the compositions according to the invention that the dissolution time of the coated alkali metal percarbonate contained therein can be specifically adjusted by adopting the morphology index as a selection criterion. Control of the release of the alkali metal percarbonate is then in particular of interest if the composition contains oxidation-sensitive enzymes: in such cases it is desirable that the enzymes can fully exert their action within the first few minutes during the washing, bleaching or cleaning, before the dissolving alkali metal percarbonate releases hydrogen peroxide and inhibits the action of the enzymes by oxidation. By selecting the morphology index the desired dissolution time can thus be adjusted within the range of less than 10 minutes.
By virtue of the possible short dissolution time according to the invention of the alkali metal percarbonate of less than 10 minutes and in particular less than 4 minutes in the compositions according to the invention, an extension of the washing, bleaching and cleaning duration can be avoided with respect to compositions that contain sodium perborate monohydrate instead of an alkali metal percarbonate, without having to accept a poorer storage stability.
The invention is illustrated in more detail on the basis of the following examples and comparison examples.
CA 02204383 l997-0~-02 ~1~
Examples a) Determination of the storage stability in washing agent mixtures:
A phosphate-free but zeolite-containing washing powder, TAED activator and a coated or uncoated sodium percarbonate (NaPc), or sodium perborate monohydrate (Pbmh) as standard and reference bleaching agents respectively, are mixed in amounts such that the mixture contains 5~ TAED and the a content is about 2.35 wt.~. Constituents in the washing powder in wt.~:
Anionic surfactants 12 Non-ionic surfactants 8 Zeolite A 36 Soda 10 Na silicates 3 Remainder, including moisture 31.
800 g of the relevant mixture are stored in commercially available, water-repellent impregnated and sealed E1 washing agent packets at 30C and 80 relative humidity in a climatically controlled cabinet. A packet is stored per withdrawal period -after 2, 4 and 8 weeks. The a content is determined in a conventional way using permanganate; the relevant a maintenance is calculated in per cent from the initial a content and the a content after 2, 4 and 8 weeks. The a* maintenance referred to the standard is calculated according to the formula:
Oa-maintenance~NaPc) a* maintenance = . .100. The a Oa-malntenance(Pbmh) maintenance of the standard with PbmH was in the range between 89 and 93~ in all examples and comparison examples.
CA 02204383 l997-0~-02 lA~5 b) Determination of the dissolution time:
2 g of coated sodium percarbonate are stirred in 1 l of water of (sic) 15C; the dissolution time is defined as the time at which 95~ has dissolved; the determination is performed conductometrically.
c) Determination of the morphology index (MI):
The product to be determined is screened using screens of nominal values (mm) 0.1; 0.2; 0.3; 0.4; 0.5; 0.6;
0.71; 0.8 and 1.0 and, as necessary (comparison examples), in addition 1.25 and 1.4 mm. The fractions are weighed and the MI is determined therefrom according to the formula.
d) Un-coated sodium percarbonate was, unless otherwise specified, produced according to DE Patent Application P 43 29 205.4 by fluidised bed spray granulation, an aqueous hydrogen peroxide solution and an aqueous sodium carbonate solution which does not contain phosphorus-containing crystallisation inhibitors being sprayed by means of a triple-substance atomiser nozzle with an extended central pipe and external mixing of the solutions in a fluidised bed that contains seeds whose dimensions are less than that of the granulate particles to be produced, and water simultaneously being evaporated at a fluidised bed temperature in the range from 40 to 95.
Unless the desired morphology index is obtained directly by the choice of the operating parameters, desired products are obtained by fractionation (screening).
CA 02204383 l997-0~-02 e) Coated sodium percarbonate:
In a fluidised bed dryer the aqueous solutions containing the coating components are sprayed in succession on to a fluidised bed composed of the sodium percarbonate (NaPc) to be coated, employing the drying air (air inlet temperature 100 to 110C) -first of all an MgSO4 solution (20 wt.~ MgSO4), followed by a combined Na2CO3/sodium silicate solution (20 wt.~ Na2CO3, 8 wt.% sodium silicate (SiO2 : Na20 approx. 3.5 : 1)). The temperature of the fluidised bed is maintained in the range from 50 to 60C, post-drying being carried out at 80 to 90C. The solutions are sprayed using conventional twin-substance nozzles with air as blowing agent.
Comparison examples VB1 and VB2 Uncoated, commercially available sodium percarbonate, produced by a crystallisation process, with different morphology index MI, was tested with regard to the a maintenance during storage. The results of the a maintenance are shown in Table 1.
T~hle 1 a maintenance (~) VBl a b c d MI 0.022 0.033 0.053 0.063 Start 100 100 100 100 2 Wo. 62 59 52 48 4 Wo. 40 35 31 29 8 Wo. 13 10 19 19 Wo. = Storage duration in weeks at 30C and 80~ relative humidity CA 02204383 l997-0~-02 :' The storage time stability of the uncoated sodium percarbonate is insufficient, irrespective of the MI.
Coated sodium percarbonate - commercially available sodium percarbonate produced by crystallisation and stabilised with 4 wt.~ MgSO4, 4 wt.~ soda and 1.6 wt.~ water glass -was tested as regards the a maintenance. The results are given in Table 2.
T~hle 2 VB2 a b c d MI 0.023 0.034 0.052 0.063 Start 100 100 100 100 2 Wo. 89 86 87 86 4 Wo. 78 73 73 72 8 Wo. 57 49 46 42 The influence of the MI on the a maintenance is hardly detectable to start with, but after 8 weeks clear differences are found.
Examples 1 to 3 Sodium percarbonate (NaPc), produced according to the general procedure in paragraph d), was coated according to paragraph e). The weight ratio of MgSO4 to soda to sodium silicate was always 5 to 5 to 2. The Tables 3, 4 and 5 show the results of the determination of the MI-, dissolution time, bulk density (Sd), initial a value, a maintenance after 8 weeks' storage at 30C and 80~ relative humidity, as well as the screening analysis. The dissolution time decreases with increasing MI without the a maintenance being reduced.
CA 02204383 l997-05-02 ~1~
In Example 1 the total amount of coating was 12~, in Example 2 6~, and in Example 3 4~, in each case referred to the sodium percarbonate core.
Table 3: NaPc with 12~ stabilising material ScrPen an-lysis, portior in % ~n scr~en in mm No. MI Dissol- Sd Oa Oa 1.4 1.25 1.0 0.8 0.71 0.6 0.5 0.4 0.3 0.2 0.1 0 ution g/l X maintenance time after 8 weeks, in X
min 1-1 0.014 34 980 11.3 91 0 0 15 56 7 14 6 2 0 0 0 0 *) 1-2 0.017 34 960 11.4 92 0 0 0 20 31 37 8 3 1 0 0 0 D
*) o 1-3 0.026 32 990 11 . 4 93 0 0 0 1 1 6 82 10 0 0 0 0 * ) r 1-4 0.036 29 1000 11 . 6 90 0 0 3 11 8 20 19 16 14 8 1 0 ~ ~
* ) ~o ~
1-5 0.036 22 1020 12.1 91 0 0 0 2 7 25 36 26 3 1 0 0 *) O
1-6 0.048 7.2 1070 11 . 3 91 0 0 0 0 0 0 19 59 19 3 0 0 O
1-7 0.051 6.2 1060 11.4 9O - - 0 0 5 10 22 31 20 9 2 1-8 0.064 2.5 1050 11 . 6 88 - - 0 0 2 8 15 30 25 15 5 0 1-9 0.075 2.0 1060 11.3 87 - - - - - 5 15 25 30 20 5 0 Table 4: NaPc with 6~ stabilising material Scr~en analysis, portion in % on screen in mm No. MI Dissol- Sd Oa Oa 1.4 1.25 1.0 0.8 0.71 0.6 0.5 0.4 0.3 0.2 0.1 0 ution g/l % maintenance time after 8 min weeks, in %
2-1 0.015 11 1000 11.9 88 0 0 3 66 6 12 7 4 2 0 0 0 *) 2-2 0.024 10.5 930 13.4 87 - 4 6 16 10 26 27 10 1 0 0 0 *) 2-3 0.030 8.6 1110 13.0 86 0 0 1 3 6 32 32 18 6 1 1 0 D
2-4 0.041 4.6 1080 13.2 88 - 0 1 5 6 17 25 19 17 9 1 0 r 2-5 0.044 4.2 1060 12.7 89 0 0 0 0 0 5 29 44 21 1 0 0 2-6 0.049 3.9 1050 12.9 86 - - 0 0 5 10 25 30 18 10 2 0 o 2-7 0.054 2.1 1070 12.8 87 - - 0 0 4 9 17 33 25 10 2 0 2-8 0.066 1.2 1040 13.1 89 - - 0 0 2 5 14 22 35 20 8 0 2-9 0.071 1.0 1050 13.0 86 - - 0 0 2 7 15 20 32 20 4 0 2-10 0.075 0.9 1060 12.8 88 - - 0 0 2 5 14 27 35 15 2 0 2-11 0.081 0.9 1050 12.9 87 - - O 0 0 2 15 27 32 16 6 2 ~ v. a C
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Claims (10)
1. Particulate washing, bleaching or cleaning agent compositions containing coated alkali metal percarbonate and conventional washing, bleaching or cleaning agent constituents, especially silicate builders, characterised in that the coated alkali metal percarbonate has an alkali metal percarbonate core produced by fluidised bed spray granulation and a single-layer or multi-layer coating of one or more stabilising compounds in an amount of 1 to 15 wt.%, referred to the sodium percarbonate core, the dissolution time of the coated alkali metal percarbonate is less than 10 minutes, measured as the dissolution time for 95% dissolution in water at 15°C
and a concentration of 2 g/l in water, the morphology index MI of the coated alkali metal percarbonate is greater than 0.03, MI being defined by the formula MI = 0.0448 . CV + 3.61 . 106 . d-3, the coefficient of variance CV being defined by the formula CV = .sigma./d, the mean grain size d being defined by the formula d = .SIGMA.d1. wi/100 and the standard deviation .sigma. being defined by the formula .sigma.= wherein di denotes the mean particle size (arithmetic mean of two screenings) of the grain fraction i and wi denotes the weight proportion of this fraction, and the fractions from the screening are obtained using screens in roughly 0.1 mm gradations from 0.1 to 0.8 mm and a 1.0 mm screen, and the Oa* maintenance in a washing agent composition containing silicate builders is at least 70% after 8 weeks' storage at 30°C and 80% relative humidity, the Oa* maintenance being the ratio, expressed in per cent, of the Oa maintenance of the composition to the Oa maintenance of a similar composition of identical Oa and stored in the same way, with sodium perborate monohydrate instead of the coated sodium percarbonate.
and a concentration of 2 g/l in water, the morphology index MI of the coated alkali metal percarbonate is greater than 0.03, MI being defined by the formula MI = 0.0448 . CV + 3.61 . 106 . d-3, the coefficient of variance CV being defined by the formula CV = .sigma./d, the mean grain size d being defined by the formula d = .SIGMA.d1. wi/100 and the standard deviation .sigma. being defined by the formula .sigma.= wherein di denotes the mean particle size (arithmetic mean of two screenings) of the grain fraction i and wi denotes the weight proportion of this fraction, and the fractions from the screening are obtained using screens in roughly 0.1 mm gradations from 0.1 to 0.8 mm and a 1.0 mm screen, and the Oa* maintenance in a washing agent composition containing silicate builders is at least 70% after 8 weeks' storage at 30°C and 80% relative humidity, the Oa* maintenance being the ratio, expressed in per cent, of the Oa maintenance of the composition to the Oa maintenance of a similar composition of identical Oa and stored in the same way, with sodium perborate monohydrate instead of the coated sodium percarbonate.
2. Composition according to claim 1, characterised in that the morphology index of the coated alkali metal percarbonate is greater than 0.04.
3. Composition according to claim 1 or 2, characterised in that it contains sodium percarbonate with a coating of one or more compounds from the series soda, sodium bicarbonate, alkali and alkaline earth metal salts of mineral acids, especially Na and Mg sulphates, alkali metal and alkaline earth metal silicates, alkali metal borates and perborates.
4. Composition according to one or more of claims 1 to 3, characterised in that the Oa* maintenance of the composition is at least 90% after 8 weeks' storage at 30°C and 80% relative humidity.
5. Composition according to one or more of claims 1 to 4, characterised in that the dissolution time of the coated alkali metal percarbonate, measured according to claim 1, is equal to or less than 4 minutes.
6. Composition according to one or more of claims 1 to 5, characterised in that it is substantially phosphate-free and contains an aluminosilicate washing agent builder from the series of zeolites or layer silicates.
7. Composition according to one or more of claims 1 to 6, characterised in that the it contains 2 to 50 wt.% of coated sodium percarbonate, silicate washing agent builders, and in addition one or more surface-active substances and one or more bleach activators, in each case in an effective amount.
8. Composition according to one or more of claims 1 to 7, characterised in that it additionally contains wash-active enzymes.
9. Process for producing a composition according to one or more of claims 1 to 8, comprising homogeneous mixing of coated alkali metal percarbonate with conventional washing, bleaching or cleaning agent constituents, individually or in premixed form, characterised in that a particulate coated alkali metal percarbonate is used that has an alkali metal percarbonate core produced by fluidised bed spray granulation and a single-layer or multi-layer coating of one or more stabilising compounds in an amount of 1 to 15 wt.%, referred to the sodium percarbonate core, a morphology index of greater than 0.03 and a dissolution time of less than 10 minutes, and its active oxygen stability, defined as the Oa*
maintenance in a washing agent composition containing silicate builders after 8 weeks' storage at 30°C and 80% relative humidity, is at least 70%, the morphology index, the dissolution time and the Oa* maintenance being defined according to claim 1.
maintenance in a washing agent composition containing silicate builders after 8 weeks' storage at 30°C and 80% relative humidity, is at least 70%, the morphology index, the dissolution time and the Oa* maintenance being defined according to claim 1.
10. Coated alkali metal percarbonate consisting of an alkali metal percarbonate core produced by fluidised bed spray granulation and a single-layer or multi-layer coating of one or more stabilising compounds in an amount of 1 to 15 wt.%, referred to the sodium percarbonate core, with a morphology index of greater than 0.03 and a dissolution time of less than 10 minutes and a Oa* maintenance in a washing agent composition containing silicate builders of at least 70% after 80 weeks' storage at 30°C and 80% relative humidity, the morphology index, the dissolution time and the Oa* maintenance being defined according to claim 1, suitable for use in compositions according to one of claims 1 to 8.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE4439069A DE4439069A1 (en) | 1994-11-02 | 1994-11-02 | Percarbonate containing detergent, bleach and detergent composition |
| DEP4439069.6 | 1994-11-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2204383A1 true CA2204383A1 (en) | 1996-05-17 |
Family
ID=6532267
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002204383A Abandoned CA2204383A1 (en) | 1994-11-02 | 1995-10-19 | Percarbonate-containing washing, bleaching and cleaning agent composition |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0789749A1 (en) |
| JP (1) | JPH10508625A (en) |
| KR (1) | KR970707266A (en) |
| CA (1) | CA2204383A1 (en) |
| DE (1) | DE4439069A1 (en) |
| FI (1) | FI971859A0 (en) |
| TR (1) | TR199501362A2 (en) |
| WO (1) | WO1996014388A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7456143B2 (en) | 2002-12-20 | 2008-11-25 | Henkel Kommanditgesellschaft Auf Aktien (Henkel Kgaa) | Bleach-containing washing or cleaning agents containing a sulfate/silicate coated percarbonate |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CZ285638B6 (en) * | 1994-10-07 | 1999-10-13 | Eka Chemicals Ab | Particles containing peroxo-compound and agent containing thereof |
| DK1092007T3 (en) * | 1998-06-30 | 2004-04-05 | Novozymes As | New improved enzyme-containing granule |
| DE19957038A1 (en) * | 1999-11-26 | 2001-05-31 | Henkel Kgaa | Detergents and cleaning agents |
| KR100743267B1 (en) * | 2001-07-19 | 2007-07-27 | 주식회사 엘지생활건강 | Sodium percarbonate superior stability and method for preparing thereof |
| DE10320196A1 (en) * | 2002-12-20 | 2004-07-08 | Henkel Kg Auf Aktien | Detergents or cleaning agents containing bleach |
| AU2003289928A1 (en) * | 2002-12-20 | 2004-07-14 | Degussa Ag | Coated peroxygen compounds with controlled release, a process for their preparation and their use |
| KR20050089974A (en) * | 2002-12-20 | 2005-09-09 | 데구사 악티엔게젤샤프트 | Liquid detergent and cleaning agent composition |
| ATE299471T1 (en) | 2003-05-07 | 2005-07-15 | Degussa | COATED SODIUM PERCARBONATE GRANULES WITH IMPROVED STORAGE STABILITY |
| DE102004054495A1 (en) | 2004-11-11 | 2006-05-24 | Degussa Ag | Sodium percarbonate particles with a thiosulfate containing shell layer |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2810379C3 (en) * | 1978-03-10 | 1980-12-11 | Degussa Ag, 6000 Frankfurt | Process for the production of stabilized sodium percarbonate |
| GB9007999D0 (en) * | 1990-04-09 | 1990-06-06 | Unilever Plc | Particulate bleaching detergent composition |
| JP2918991B2 (en) * | 1990-05-25 | 1999-07-12 | 三菱瓦斯化学株式会社 | Bleach detergent composition |
| US5332518A (en) * | 1992-04-23 | 1994-07-26 | Kao Corporation | Stable slurry-coated sodium percarbonate, process for producing the same and bleach detergent composition containing the same |
| US5328721A (en) * | 1992-07-30 | 1994-07-12 | Fmc Corporation | Process for manufacturing sodium carbonate perhydrate particles and coating them with sodium borosilicate |
| DE4311944A1 (en) * | 1993-04-10 | 1994-10-13 | Degussa | Coated sodium percarbonate particles, process for their preparation and detergent, cleaning and bleaching compositions containing them |
| DE69404543T2 (en) * | 1993-05-06 | 1997-12-04 | Mitsubishi Gas Chemical Co | Stabilized sodium percarbonate particles |
| DE69326833D1 (en) * | 1993-07-14 | 1999-11-25 | Procter & Gamble | Stabilized detergent compositions |
-
1994
- 1994-11-02 DE DE4439069A patent/DE4439069A1/en not_active Withdrawn
-
1995
- 1995-10-19 KR KR1019970702910A patent/KR970707266A/en not_active Application Discontinuation
- 1995-10-19 WO PCT/EP1995/004102 patent/WO1996014388A1/en not_active Application Discontinuation
- 1995-10-19 JP JP8514988A patent/JPH10508625A/en active Pending
- 1995-10-19 CA CA002204383A patent/CA2204383A1/en not_active Abandoned
- 1995-10-19 EP EP95936523A patent/EP0789749A1/en not_active Withdrawn
- 1995-11-02 TR TR95/01362A patent/TR199501362A2/en unknown
-
1997
- 1997-04-30 FI FI971859A patent/FI971859A0/en not_active Application Discontinuation
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7456143B2 (en) | 2002-12-20 | 2008-11-25 | Henkel Kommanditgesellschaft Auf Aktien (Henkel Kgaa) | Bleach-containing washing or cleaning agents containing a sulfate/silicate coated percarbonate |
Also Published As
| Publication number | Publication date |
|---|---|
| FI971859A (en) | 1997-04-30 |
| KR970707266A (en) | 1997-12-01 |
| JPH10508625A (en) | 1998-08-25 |
| DE4439069A1 (en) | 1996-05-09 |
| TR199501362A2 (en) | 1996-06-21 |
| FI971859A0 (en) | 1997-04-30 |
| EP0789749A1 (en) | 1997-08-20 |
| WO1996014388A1 (en) | 1996-05-17 |
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