[0001] The present invention relates to the granulation of powders to improve their storage
stability in particular of bleach activator powders to form granulates for detergent
powders.
[0002] It is well known to incorporate into detergent compositions bleaching compounds such
as perborates and other peroxy bleaches and to activate the bleaches
in situ using activators for these bleach compounds. The activators must be prevented from
coming into contact with the bleach in the presence of water so as to reduce or eliminate
reaction of the activator with the bleach compound prior to dissolution of the entire
detergent composition in water. This may be done by providing the bleach and bleach
activator in separate compositions or by forming the activator into dry granules with
binder, the granules being one component in the dry particulate detergent composition.
[0003] In DE-A-2048331 bleach activator granules are produced by mixing dry particles of
the activator with inorganic salts containing water of hydration and then moistening
the blend with water or a solution of granulating aid, which is selected from inorganic
salts, organic binders and detergent compounds.
[0004] An improvement of the process in DE-A-2048331 is described in EP-A-0037026 where,
instead of incorporating all of the organic binder in solution or dispersion in the
water used to moisten the dry bleach activator, part or all of the binder is mixed
as dry particles with the activator particles, before the moistening takes place.
The organic binders which may be used are selected from starch and cellulose and starch
derivatives.
[0005] In EP-A-0238341 dry particles of activator and organic binder are moistened with
a solution of a sequestering agent, usually a polyphosphonic acid. The binder can
be a synthetic polymer, polyacrylates, polymaleates and polyvinyl pyrrolidones being
mentioned, but is usually a derivative of a natural polymer such as a cellulose ether,
usually carboxymethyl cellulose (CMC).
[0006] In EP-A-0240057 bleach activator compositions containing a plain material are produced
for instance by moistening a dry mix of the activator with an aqueous dispersion containing
the clay and a water-soluble film forming polymer having a low content of carboxyl
groups. The film forming polymer is usually a synthetic polymer formed from ethylenically
unsaturated compounds. Specific examples used are copolymers of maleic anhydride and
vinyl methyl ether and of maleic acid and acrylic acid. The film-forming polymers
must be water soluble and are used in the process in solution and are the sole organic
binders.
[0007] In EP-A-0241962 a non-phosphorous bleach activator granule is provided by moistening
a dry mix of particulate activator with an aqueous solution of a low- to non-carboxylate
film-forming polymer. The polymer may be a synthetic polymer formed from ethylenically
unsaturated monomers or may be a natural polymer or derivative, such as carbohydrates
and carbohydrate ethers. Polymers which are specifically exemplified are polyvinyl
acetate and a vinyl dextrin polymer. The polymer is apparently water-soluble since
it is used in aqueous solution.
[0008] In EP-A-0,292,314 components of detergent compositions including a chlorine-releasing
bleaching additive, manganese gluconate (a catalyst for peroxygen bleaching), diperoxydodecanedioic
acid (a peroxygen bleach) and potassium dichlorocyamuric acid are encapsulated. The
process involves suspending the powders in a fluidised bed, then introducing a polymer
latex into the fluidised bed, the bed being kept at a temperature of about or above
the glass transition temperature of the polymer in the latex. The polymer is insoluble
in water at pH 7 but is soluble or swellable in alkali. Polymers used are copolymers
of (meth)acrylic acid with esters thereof, preferably having glass transition temperature
in the range 30 to 80°C. The process used is termed the Wurster procedure as described
in US-A-3253944 and is carried out in apparatus supplied by Aeromatic or Glatt.
[0009] Wurster (US-A-3253944) describes a process in which particles are sprayed with coating
material which is introduced into high velocity fluidising airstream. The airstream
is heated so that the coating is dried. The process is conducted batchwise, that is
a batch of powder is introduced into the tower, fluidised and, when coating of the
material is sufficient, the fluidising gas is turned off and the product removed.
[0010] A new procees according to the present invention in which particles of a detergent
additive having an average particle size in the range 20 to 300 µm are agglomerated
by moistening them while mixing with an aqueous liquid in the presence of a film-forming
polymer which has a lower solubility in water at pH 7 than in aqueous solution at
pH 10 is characterised in that the process is carried out in two separate stages,
in the first stage of which the particles are mixed om a high shear mixer with the
aqueous liquid in the presence of film-forming polymer and in the second of which
the moist product of stage one is dried at raised temperature, and in that the agglomerated
product has an average particle size in the range 300 to 1400 µm.
[0011] In this specification the solubility of the polymer is measured by the following
technique.
[0012] Firstly dried samples of all the polymers are obtained. Where necessary the solvent
or dispersing liquid in the product as supplied is removed under vacuum at 70°C. Portions
(1g) of each dried polymer are then dispersed in a small amount of deionised water,
or suitable organic solvent, in two 100ml beakers. The solvent is then completely
removed by heating at up to 70°C under partial vacuum for several hours. As a result
a uniform thickness of dry polymer film is obtained. The beakers are then tared.
[0013] Deionised water (50ml), at pH7, is added to one of each of the prepared polymer samples,
and 50ml of dilute sodium hydroxide solution (pH10) is added to the remainder. The
beakers are left to stand for 16 hours at room temperature. The liquid is then carefully
removed. Each beaker is dried at reduced pressure at 70°C to remove all entrained
solvent. Further heating 120°C is required with vacuum, in some cases, to remove retained
solvent. Each beaker is then reweighed and the loss of polymer assessed.
[0014] The solubility is given as the percentage of polymer removed with the solvent.
[0015] The solubility in water at pH7 should be less than about 50 preferably less than
20, more preferably less than 10 for the polymer to be of use in the present invention.
The solubility can be less than 5 or even as low as about 2.
[0016] The solubility in alkaline solution at pH10 should be at least 5, preferably at least
10 and often at least 20, for instance around 50 or more. The solubility should be
higher than in water at pH7.
[0017] In the new process the polymer is preferably added to the detergent additive particles
in the form of an aqueous dispersion of polymer particles. The polymer particles preferably
have a size of less than 25 µm, more preferably less than 10 µm, and even more preferably
less than 5 µm, for instance around 1 µm or less. The polymer is preferably an emulsion
polymer, ie a polymer which has been prepared as an emulsion and so the polymer dispersion
is itself an emulsion.
[0018] The concentration of polymer in the dispersion is usually at least 10% by weight,
preferably at least 20% by weight, more preferably more than 40% by weight and can
be as much as 50% or more. The aqueous liquid in which the polymer particles are suspended
is such as to prevent dissolution of the polymer into the liquid.
[0019] The polymer dispersion is preferably the product of an oil-in-water polymerisation
of an emulsion of water-insoluble ethylenically unsaturated monomer or monomer blend.
The product may be the direct product of such a polymerisation or may have further
additives or may have had other components removed following the polymerisation process.
Preferably it is the direct product and thus preferably contains any stabiliser or
emulsifier used in the polymerisation. Such polymerisation methods are known per se.
[0020] When the granule produced by a process in which an aqueous dispersion of a water-insoluble
polymer is used, the water of the aqueous dispersion is removed in the drying step,
allowing the particles to fuse to form a film of polymer on the granule surface.
[0021] In the new processes it is often helpful to incorporate additionally a non-film-forming
binder, for instance one of the conventional starch or cellulose derivatives used
in the above mentioned prior art. The non-film-forming binder is preferably used in
the form of dry particles and is thus usually premixed with the particulate activator.
It could alternatively be dissolved in the aqueous granulating liquid by which the
dry activator is moistened.
[0022] Any non-film-forming binder is generally present in an amount of less 10% by weight,
more preferably less than 5% by weight and most preferably less than 2% by weight,
based on the composition of the product granules. The amount of non-film-forming binder
is thus preferably lower than that required to give adequate binding in the absence
of the film-forming polymer.
[0023] The film-forming polymer is generally used in an amount of at least 0.1% by weight,
preferably at least 1% by weight. Usually the amount of film-forming polymer does
not need to be higher than 75% and is usually less than 50%, preferably less than
25% by weight, and is more preferably less than 10% by weight. The amounts are based
on the weight of the product granules.
[0024] The particles are used in an amount such that the detergent additive is present in
the product of the process in an amount of at least 20%, preferably in the range 50
to 99% by weight more preferably 70-90% by weight.
[0025] The particles of detergent additive which are granulated in the process may be any
particles which are required to be agglomerated for instance to render them more easily
handlable (being of larger particle size) or, usually, more storage stable by preventing
chemical reaction with other active compounds in their environment.
[0026] The particles are materials used in detergents, such as catalysts, colourants or
enzymes. The invention is of particular benefit in granulating bleach components for
instance precursors for bleaches, for instance chlorine-releasing bleach additives,
peroxygen-releasing bleach additives or, most suitably, bleach activators.
[0027] Particulate bleach activators include organic activators which are compounds which
form carboxylic peracids on reaction with perhydroxyl ions in wash liquor. An organic
activator is preferably tetra acetyl ethylene diamine but may be any of the known
detergent bleach activators, such as those described in GB-A-2,048,930 or EP-A-0037026.
Other preferred activators include polyacetyl mono-, di-, or polysaccharides such
as penta acetyl glucose, sulphonates such as isononanoyl oxybenzene sulphonate, nonyl
benzoates glycourils such as tetra acetyl glycouril, N-acyl amides, acylated diketopiperazines,
and other N-acyl amines. Inorganic catalysts such as manganese salts may also be treated
in the process.
[0028] By using the above mentioned processes the granules which are formed have a greatly
improved strength compared to granules formed using the cellulose or starch derivatives
used in the prior art. It is believed that the film-forming polymers form a non-brittle
film around the granules which is resistant to breaking up. This improves their storage
stability and handling properties.
The film-forming binder improves the physical form of the granules by providing them
with a film coating, whereas in the prior art using the non-film-forming binder alone
produces granules having small particles of binder on the surface which can form dust
after storage and which tend to break up by attrition to form dust comprising activator
particles and binder particles.
[0029] The application of the film-forming polymer from an aqueous dispersion allows the
use of concentrated dispersions, which have low viscosities and are therefore easily
handleable, which means that a relatively small amount of water is added in the process
which means there is less water to evaporate in the drying step. The polymer becomes
more evenly dispersed than if it is added as a solid. When the film-forming polymer
is used in conjunction with a non-film-forming binder, the combination allows low
amounts of each component to be used. The use of non-film-forming polymer in conjunction
with the film-forming polymer allows a greater rate of throughput in the granulating
step than the process using the film-forming polymer alone.
[0030] The use of a film-forming polymer which is soluble in alkaline solution but not in
water, as well as allowing the process benefits described above from the application
from aqueous dispersion, allows the production of granules which disperse and dissolve
easily in the laundry wash liquor. The granules are chemically very stable on storage
as water is not attracted to the granules so that premature contact and reaction of
the activator and bleach in the presence of water cannot take place.
[0031] A granular bleach activator when used in a laundry detergent, results in a decrease
in localised dye and fabric damage ("pinpoint spotting") thought to be due to high
local concentrations of bleach, as compared to granules produced by binding with CMC
alone.
[0032] The film-forming polymer is preferably formed from a water-insoluble blend of ethylenically
unsaturated monomers. To provide suitable solubility characteristics the monomer preferably
includes an acidic monomer, for instance a carboxylic acid or sulphonic acid monomer.
Suitable monomers are maleic acid, acrylic acid and, most preferably, methacrylic
acid. The acid monomers are generally copolymerised with a suitable amount of a comonomer
such as alkyl esters or amides of those acids or alkyl amide derivatives of the corresponding
amides of the carboxylic acids. Suitable comonomers are thus lower alkyl esters of
acrylic and methacrylic acid, usually the C₁₋₄ alkyl esters. The polymers preferably
have molecular weights of up to 5,000,000, preferably up to 1,000,000. The molecular
weight is preferably at least 500, more preferably at least 1,000 and most preferably
5,000 or more. The polymerisation is carried out in the conventional manner, preferably
by the oil-in-water suspension or emulsion polymerisation described above.
[0033] By selection of suitable ratios of monomer components and producing a polymer of
an appropriate molecular weight, the polymers can be provided with the preferred solubility
characteristics. The inclusion of acid monomers provides the polymers with their alkali
solubility since in the presence of alkali the acidic monomers will be ionised which
will increase their solubility.
[0034] Suitable polymers are for instance those used for enteric film coatings, such as
those used for pharmaceuticals and which are insoluble in gastric juices (which is
acidic) but soluble in alkaline media such as intestinal juices. Such polymers are
for instance available under the Eudragit trade mark, for instance the Eudragit L
series and the Eudragit S series. Another suitable polymer is available under the
Glascol trade mark from Allied Colloids Limited.
[0035] Where the particles granulated are of bleach activator the granules may contain sequestering
agents, to improve the rate of disintegration and the stability of the bleach in the
laundry liquid. Such sequestering agents are for instance any of the phosphonates
used in EP-A-0238341. The sequestering agent may be added in the granulated liquid
or may be used in particulate form as one of the dry ingredients. Furthermore the
granule may contain an inorganic salt, such as sodium chloride, sodium sulphate, sodium
nitrate, sodium citrate or sodium carbonate or magnesium sulphate. The inorganic salt
may be added in the granulating liquid or as part of the dry ingredients, in particulate
form.
[0036] The process may include the use of granulating binders additional to the film-forming
and non-film-forming binders mentioned earlier. For instance it may sometimes be advantageous
to include a small amount of a granulating liquid at the beginning or end of the granulating
process, comprising an aqueous solution of a film-forming polymer such as a vinylmethylether/maleic
acid copolymer, a polyacrylic acid homopolymer, usually in salt form, or polyvinyl
pyrrolidone.
[0037] Other components of the final composition may be included in the granulating process
if desired in any suitable amounts. Preferably however such additions provide less
than 10% and generally less than 5% by weight of the granules. One component that
can usefully be included in granules for detergent composition is optical brightening
agent since its incorporation in the granules avoids the problems associated with
incorporating it in the remainder of the detergent composition. For instance it may
be damaged by the spray drying to which the remainder of the composition is generally
subjected. Another component that can conveniently by co-granulated is an antisudsing
(anti foaming) or foam stabilising agent. Other components that may be cogranulated
are other components of detergent compositions such as surfactants, anti redeposition
acids, builders, pigments or dyes, perfumes and enzymes.
[0038] The particles to be granulated should be provided in the form of small particles
having an average particle size in the range 20 to 300 µm. Preferably substantially
none of the particles has a size above 300 µm or, at the most, 500 µm. The particulate
binder preferably has an average particle size below 200 µm, generally below 100 µm
and is preferably free of particles above 200 µm in size.
[0039] During the mixing and contacting stage it is preferred that no external heating source
heats the apparatus, the air surrounding the particles or the liquid components. The
mixing applies a large amount of kinetic energy to the particles. The mixing and contacting
of the liquid component(s) is preferably carried out whilst the particles fall under
the influence of gravity as well as being given kinetic energy by the mixer.
[0040] The mixing and contacting step itself can be carried out by apparatus and methods
known per se, in which the dry ingredients are mixed and after or substantially simultaneously
with mixing in a high shear mixer are contacted with the liquid component(s), for
instance by spraying. The process may be carried out in, eg a Schugi Flexomix or a
Lödige mixer.
[0041] Once the granules have passed through the first stage in which the liquid components
are contacted with the particles they are subsequently dried in a separate stage and
in a separate part of the apparatus. The drying is conveniently carried out in a fluidised
bed which prevents further agglomeration of the granules. The bed is kept at a temperature
at which drying is adequately fast but below which the active material(s) becomes
unstable. A suitable temperature is in the range 30-100°C, for instance 40-80°C.
[0042] The process is usually carried out continuously which allows good control of the
product quality to be achieved and is more efficient than a batch process of the type
described in EP-A-0292314.
[0043] The granules preferably have an average particle size of 300 to 1400 µm. Preferably
substantially none of them have a size above 2000 µm and preferably not above 1700
µm. Preferably none of the granules have a size below 50 µm and most preferably none
have a size below about 125 µm.
[0044] The resultant granules can be incorporated in to compositions, for instance conventional
detergent compositions including laundry detergent compositions, in solid (particulate)
gel or liquid form. Where the active compound in the particle is bleach activator
the detergent composition usually contains suitable bleach component that is activated
by the activator. The preferred bleaches are peroxy compounds, especially perborates
such as sodium perborate tetrahydrate but others that can be used include sodium perborate
monohydrate or sodium percarbonate.
[0045] A detergent composition containing the granules may contain, in addition to surfactants,
detergent builders and anti-redeposition aids, enzymes, anti-sudsing agents, foam
stabilisers, optical brightening agents, pigments, dyes and perfumes, sequestrants,
halide salts such as sodium bromide, manganese salts such as mananous sulphate and
inert fillers such as sodium sulphate or silicate. A particular advantage of the invention
is that it is not necessary to include phosphates, although they may be included if
desired. Typical amounts are 1 to 5% based on the total detergent, or 10 to 50% based
on the bleach.
[0046] The following examples illustrate the invention.
Product Test Methods
[0047] The following tests are used:
1. Storage stability of granules.
[0048] The granules are stored at 80% relative humidity and 37°C for 4 hours to simulate
adverse storage conditions. The granules are then inspected and subjectively assessed
for their physical properties to assess their loss of granule integrity due to moisture
uptake. They are rated on a scale of 1 (almost no change) to 10 (almost total loss
of structure).
2. Fabric Damage
[0049] It is intended that the test represents undissolved detergent adhering to clothing
during prolonged soaking. Woven woollen cloth, treated by the Hercosett process and
undyed, was obtained from the Society of Dyers and Colourists, Bradford, West Yorkshire.
[0050] The test detergent formulation is enclosed in a "pouch" of wool which is left to
soak for 16 hours in water at room temperature. After rinsing and drying the pieces
were examined by eye and ranked on a scale of 1 to 10, higher numbers being worse
according to the number of raised yellow spots present. These are areas which have
been irreversibly damaged by peroxygen species.
3. Compressability and particle size distribution change after compression.
[0051] A cylindrical mould is filled with the granular material, thus it initially contains
a fixed volume of the material. The granular material has previously been stored for
a period of four hours at a temperature of 37°C and at a relative humidity of 80%,
in order to simulate severe storage conditions. A plunger is pressed down on the top
of the material in the die at a standard pressure of 1.298 x 10⁵ kgf/m for a period
of 5 minutes, to simulate a period of time at the bottom of a large storage bag. The
volume change can be measured at this stage.
[0052] The particle size distribution of the granules is measured by sieve analysis after
the storage step of a) and again after the compression test. The results are reported
as the percentage change of particles within the stated size range or retained on
the sieve of the stated size (as specified in the results).
Polymers
[0053] The following film-forming polymers are used to form granules:
A Glascol polymer - an emulsion believed to contain a polymer formed from monomers
including about 20-25 mole % methacrylic acid with alkyl (meth)acrylates (Allied Colloids)
Viscalex VG2 - acrylic acid ester copolymer, emulsion (Allied Colloids - Viscalex
is a trade mark).
Gantrez S-97 - methylvinyl ether - maleic acid copolymer solution, (GAF - Grantrez
is a trade mark).
PVP K-30 - polyvinyl pyrrolidone, solid (GAF)
[0054] Each polymer was tested for its solubility at pH 7 and pH 10 by the method described
above. The results are shown in Table 1.
TABLE 1:
SOLUBILITY AT pH 7 and pH 10 |
|
pH 7 |
pH 10 |
GLASCOL |
2 |
50 |
VISCALEX VG2 |
6 |
20 |
GANTREZ S-97 |
100 |
100 |
GAF PVP K-30 |
100 |
100 |
Examples 1-4 (Comparative A-C)
[0055] In the following examples the dry components (TAED, Na₂SO₄ and binder (where appropriate))
are mixed in a laboratory granulator for about 3 minutes after which the liquid components
(water and/or binder dispersion or solution, where appropriate) are sprayed on whilst
mixing is continued for a further 2 minutes. The granular product is then discharged
and dried for 15 minutes at 60°C using a fluid bed drier. The proportions of the components
in the resultant product is shown in the following table:
TABLE 2:
EXAMPLE FORMULATIONS |
EXAMPLE |
A |
B |
C |
1 |
2 |
3 |
4 |
TAED |
92 |
92 |
88 |
89 |
86 |
92 |
90 |
GLASCOL |
|
|
|
4.9 |
9.6 |
7 |
|
VISCALEX VG2 |
|
|
|
|
|
|
4.5 |
GANTREZ S-97 |
|
|
10 |
|
|
|
|
PVP K-30 |
|
7 |
|
|
|
|
|
CMC |
7 |
|
|
0.3 |
|
|
0.3 |
Na₂SO₄ |
|
|
|
4.9 |
|
|
4 |
|
|
|
|
|
WATER |
to 100% |
In example A (comparative) the CMC was added as dry powder. In examples B, C and
1-4 the CMC was added as a 4% aqueous solution.
The film-forming polymers are added as supplied, ie the emulsion polymers are added
with the liquid and the solid polymers are added with the dry ingredients.
[0056] The products are then subjected to the above-described tests. The results are shown
in Table 3.
TABLE 3:
RESULTS OF TESTS |
Test/Composition |
A |
B |
C |
1 |
2 |
3 |
4 |
1 |
10 |
7 |
5 |
2 |
2 |
4 |
2 |
2 |
8 |
|
|
3 |
3 |
3 |
9 |
3 less than 425µm |
18 |
16 |
13 |
9 |
|
|
16 |
more than 600µm |
-13 |
-9 |
-4 |
-1 |
|
|
-6 |
The results show that the compositions formed by the process of the invention including
a film-forming polymer with the defined solubility characteristics as well as cmc
are less susceptible to deterioration during storage, having reduced particle size
change in the test 3b and better results on the subjective storage test, no. 1. The
results are also improved compared to the comparative examples using the film-forming
polymers that are soluble at pH7. The results also show that the fabric damage is
far less for the composition containing the Glascol product which is far more soluble
at pH10 than pH7 (examples 1-3) than for the conventional granule. The composition
formed with the other emulsion polymer Viscalex also has desirable overall characteristics.
Example 5
[0057] Granules were produced in a similar manner as described above to give a product which
consisted of 90.8% TAED, 3.6% cmc, 4.3% NaSO₄. The granules were subjected to the
compressibility test, test 3, and compared with comparative example A as used above.
The results are shown in Table 4.
TABLE 4
|
|
COMPOSITION |
|
Test |
A |
Example 5 |
3 size fraction |
retained on 850µm |
-29.4 |
0.0 |
retained on 710µm |
-33.4 |
2.9 |
retained on 600µm |
-26.4 |
3.6 |
retained on 500µm |
-13.0 |
2.1 |
retained on 425µm |
-4.1 |
1.1 |
less than 425µm |
0 |
0 |
% change in volume |
25 |
12.6 |
Results show that A tends to break down significantly and compress substantially.
Example 5 tends to aggregate only very slightly - almost insignificantly - as well
as resisting compression as compared to conventional formulation (A) using cmc alone.
1. A process in which particles of a detergent additive having an average particle size
in the range 20-300µm are agglomerated by moistening them while mixing with an aqueous
liquid in the presence of a film-forming polymer which has a lower solubility in water
at pH 7 than in aqueous solution at pH 10 characterised in that the process is carried
out in two separate stages, in the first stage of which the particles are mixed in
a high shear mixer with the aqueous liquid in the presence of film-forming polymer
and in the second of which the moist product of stage one is dried at raised temperature
and in that the agglomerated product has an average particle size in the range 300
to 1400µm.
2. A process according to claim 1 in which the polymer is added to the particles in the
form of an aqueous dispersion of polymer particles.
3. A process according to claim 2 in which the polymer particles have a size of less
than 25 µm.
4. A process according to claim 3 in which the polymer particles have a size of less
than 10 µm, preferably less than 5 µm, more preferably around 1 µm or less.
5. A process according to any of claims 2 to 4 in which the polymer dispersion is an
emulsion, which is preferably the product of an oil-in-water polymerisation of an
emulsion of water-insoluble ethylenically unsaturated monomer or monomer blend.
6. A process according to any preceding claim in which a non-film-forming binder is incorporated,
which is preferably a starch or a cellulose derivative.
7. A process according to claim 6 in which the non-film-forming binder is added as dry
binder particles, preferably premixed with the said particles.
8. A process according to any preceding claim in which the film forming polymer is used
in an amount of at least 0.1% by weight, preferably at least 1% by weight, usually
less than 25% and preferably less than 10% by weight based on the weight of the product
granules.
9. A process according to any preceding claim in which the particles of detergent additive
comprise a bleach component, preferably a bleach precursor or a bleach activator,
most preferably tetraacetylethylenediamine.
10. A granular detergent composition containing the product of a process according to
any preceding claim.
11. A composition according to claim 10 in which the particles comprise bleach activator
and which further comprises a bleach component that is capable of being activated
by the bleach activator in aqueous solution.
1. Verfahren, in welchem Teilchen eines Detergens-Additivs mit einer durchschnittlichen
Teilchengröße im Bereich von 20 - 300 µm agglomeriert werden durch Befeuchtung, während
man sie mit einer wäßrigen Flüssigkeit in Anwesenheit eines filmbildenden Polymers,
das in Wasser bei pH 7 eine niedrigere Löslichkeit als in wäßriger Lösung bei pH 10
aufweist, mischt, dadurch gekennzeichnet, daß das Verfahren in zwei getrennten Stufen
durchgeführt wird, wobei in der ersten Stufe die Teilchen mit der wäßrigen Flüssigkeit
in Anwesenheit von filmbildendem Polymer in einem Hochscher-Mischer gemischt werden
und in der zweiten Stufe das feuchte Produkt von Stufe 1 bei angehobener Temperatur
getrocknet wird, und daß das agglomerierte Produkt eine durchschnittliche Teilchengröße
im Bereich von 300 bis 1400 µm aufweist.
2. Verfahren nach Anspruch 1, in welchem das Polymer den Teilchen in Form einer wäßrigen
Dispersion von Polymer-Teilchen zugesetzt wird.
3. Verfahren nach Anspruch 2, in welchem die Polymer-Teilchen eine Größe von weniger
als 25 µm aufweisen.
4. Verfahren nach Anspruch 3, in welchem die Polymer-Teilchen eine Größe von weniger
als 10 µm, vorzugsweise weniger als 5 µm, noch bevorzugter etwa 1 µm oder weniger,
aufweisen.
5. Verfahren nach irgendeinem der Ansprüche 2 bis 4, in welchem die Polymer-Dispersion
eine Emulsion ist, die vorzugsweise das Produkt einer Öl-in-Wasser-Polymerisation
einer Emulsion von wasserunlöslichem ethylenisch ungesättigtem Monomer oder Monomer-Mischung
ist.
6. Verfahren nach irgendeinem vorangehenden Anspruch, in welchem ein keinen Film bildendes
Bindemittel, das vorzugsweise eine Stärke oder ein Cellulose-Derivat ist, einverleibt
wird.
7. Verfahren nach Anspruch 6, in welchem das keinen Film bildende Bindemittel in Form
trockener Bindemittel-Teilchen, vorzugsweise mit den Teilchen vorgemischt, zugesetzt
wird.
8. Verfahren nach irgendeinem vorangehenden Anspruch, in welchem das filmbildende Polymer
in einer Menge von mindestens 0,1 Gewichts-%, vorzugsweise mindestens 1 Gewichts-%,
üblicherweise weniger als 25 Gewichts-% und vorzugsweise weniger als 10 Gewichts-%,
bezogen auf das Gewicht der Produkt-Körner, eingesetzt wird.
9. Verfahren nach irgendeinem vorangehenden Anspruch, in welchemdieDetergens-Additiv-TeilcheneineBleichmittel-Komponente,
vorzugsweise eine Bleichmittel-Vorstufe oder einen Bleichmittel-Aktivator, am meisten
bevorzugt Tetraacetylethylendiamin, umfassen.
10. Granuläre Detergens-Zusammensetzung, enthaltend das Produkt eines Verfahrens gemäß
irgendeinem vorangehenden Anspruch.
11. Zusammensetzung nach Anspruch 10, in welcher die Teilchen Bleichmittel-Aktivator umfassen
und die weiter eine Bleichmittel-Komponente umfaßt, die in wäßriger Lösung durch den
Bleichmittel-Aktivator aktiviert werden kann.
1. Procédé dans lequel les particules d'un additif détergent, ayant une taille particulaire
comprise entre 20 et 300 µm, sont agglomérées par leur humectation cependant qu'elles
sont mélangées avec un liquide aqueux en présence d'un polymère filmogène qui a dans
l'eau à pH 7 une solubilité inférieure à celle observée dans une solution aqueuse
à pH 10, procédé caractérisé en ce que le procédé est mis en oeuvre en deux étapes
séparées ; dans la première étape du procédé, les particules sont mélangées dans un
mélangeur à cisaillement élevé avec le liquide aqueux en présence du polymère filmogène
et, dans la seconde étape, le produit humecté provenant de l'étage ou de l'étape 1
est séché à température élevée, et en ce que le produit aggloméré a une taille particulaire
moyenne comprise entre 300 et 1 400 µm.
2. Procédé selon la revendication 1, dans lequel le polymère est ajouté aux particules
en étant sous forme d'une dispersion aqueuse de particules du polymère.
3. Procédé selon la revendication 2, dans lequel les particules du polymère ont une taille
inférieure à 25 µm.
4. Procédé selon la revendication 3, dans lequel les particules du polymère ont une taille
inférieure à 10 µm, de préférence inférieure à 5 µm et encore mieux une taille voisine
de 1 µm ou même inférieure.
5. Procédé selon l'une quelconque des revendications 2 à 4, dans lequel la dispersion
du polymère est une émulsion, qui est de préférence le produit d'une polymérisation
du type huile-dans-eau d'une émulsion d'un monomère ou d'un mélange de monomères à
insaturation éthylénique, qui est insoluble dans l'eau.
6. Procédé selon l'une quelconque des revendications précédentes, dans lequel un liant
non filmogène est incorporé, ce liant étant de préférence un amidon ou une fécule
ou un dérivé de la cellulose.
7. Procédé selon la revendication 6, dans lequel le liant non filmogène est ajouté sous
forme de particules sèches de liant, de préférence prémélangées avec lesdites particules.
8. Procédé selon l'une quelconque des revendications précédentes, dans lequel le polymère
filmogène sert en une quantité d'au moins 0,1 % en poids, de préférence au moins 1
% en poids, habituellement moins de 25 % et de préférence moins de 10 % en poids,
sur la base du poids des granules du produit.
9. Procédé selon l'une quelconque des revendications précédentes, dans lequel les particules
de l'additif détergent comprennent un constituant à rôle de blanchiment, de préférence
un précurseur d'agent de blanchiment ou un activateur de blanchiment, de façon extrêmement
préférable de la tétraacétyléthylènediamine (TAED).
10. Composition de détergent granulaire contenant le produit d'un procédé selon l'une
quelconque des revendications précédentes.
11. Composition selon la revendication 10, dans laquelle les particules comprennent de
l'activateur de blanchiment et qui, en outre, comprend un constituant à rôle d'agent
de blanchiment qui est capable d'être activé par l'activateur de blanchiment en solution
aqueuse.