[0001] The present invention relates to a free-flowing powder having a high bulk density
comprising certain polymers useful as dye transfer inhibitors in the cleaning of,
for example, laundry items.
The invention also relates to a process for making the free-flowing powder.
[0002] The use of various polymers as dye transfer inhibitors in detergent compositions
has been described in the prior art. One method of incorporating the polymers into
granular detergent compositions has been to dry mix powdered polymers with other granular
components.
[0003] However it has been noted that there is a problem of lumping and caking of granular
detergents associated with using hygroscopic polymer powders in this way. Furthermore
there are difficulties of bulk handling the those powders.
[0004] US5259994 has addressed these problems by mixing polyvinyl pyrollidone with zeolite,
a hydrating salt (e.g. carbonate) and a binding agent to prepare a free-flowing detergent
additive. However, the small, anhydrous additive readily absorbs water upon contact.
The resulting gel can have an adverse effect on product dispensing.
[0005] US4414130 discloses a "readily disintegrable, insoluble, detergent builder particulate
agglomerate comprising [aluminosilicate] held together by a water soluble binder."
One such binder which is mentioned is Polyclar ®, a PVP supplied by GAF. Methods of
manufacturing agglomerates include the use of a fine spray of water to promote adhesion.
Example 2(B) discloses a solution of polyvinyl pyrollidone and polyvinyl alcohol which
is agglomerated with zeolite. This patent is not, however, concerned with the problems
of formulating and processing dye transfer inhibiting agents.
[0006] GB-A-1 348 212 relates to detergent compositions with improved dye-transfer control
characteristics comprising 60 to 95 % by weight of nonionic detergent and a homopolymer
of vinylpyrrolidone or a copolymer of vinylpyrrolidone and a suitable comonomer.
[0007] H. Jäger et al ("Wirkungsweise von Polymeren mit farbübertragungsinhibierende Eigenschaften"
Tenside Surfactants Detergents (München),
28(6), pp 428-433 (November 1991) investigates the relationship between the structure,
composition and molar mass of some polymers and their ability to prevent dye-transfer.
[0008] Although polyvinyl pyrrolidone is useful as a dye transfer inhibitor, other polymers
are being sought which are even more effective. A more effective polymer is one which
can be used in smaller quantities than polyvinyl pyrollidone to achieve the same effect,
and which is cheaper.
[0009] In today's granular detergent market it is particularly important to find an efficient
dye transfer inhibition polymer (or a mixture of polymers) which can be easily handled
as a high bulk density granule, and which can be added in. small amounts to compact
products and which does not have an adverse effect on product dispensing.
[0010] The present invention provides a high density agglomerate which comprises copolymers
of N-vinylpyrrolidone and N-vinylimidazole, at levels of 5% to 50% by weight, comprising
very low levels of surfactant, ie. less than 2 % by weight.
[0011] The present invention also provides a process in which a premix of specific hygroscopic
dye transfer inhibition polymer with zeolite (or other powder) is prepared prior to
agglomeration.
Summary of the Invention
[0012] In a first aspect, the present invention provides a free-flowing powder having a
bulk density of at least 600 g/l comprising:
(a) from 20% to 95% by weight (on anhydrous basis) of a detergent ingredient selected
from the group consisting of aluminosilicate, citrate, silica, carbonate, bicarbonate,
silicate, sulphate, phosphate, water-soluble polymer and mixtures thereof; and
(b) from 5% to 50% by weight of a copolymer of N-vinylpyrrolidone and N-vinylimidazole.
Whilst the free-flowing powder may comprise other components, the level of surfactant
is than 2% by weight of the powder.
[0013] Preferably the free-flowing powder comprises (a) from 50% to 75% by weight (on anhydrous
basis) of aluminosilicate and (b) a mixture of polyamine N-oxide and copolymer of
N-vinylpyrrolidone and N-vinylimidazole, the total polymer level being from 10% to
30% by weight of the powder.
[0014] The mixture of polyamine N-oxide and copolymers of N-vinylpyrrolidone and N-vinylimidazole
is typically in the ratio of from 5:1 to 1:5, and is preferably about 1:1.
[0015] In a second aspect the present invention provides a process for making free-flowing
particles comprising hygroscopic powders of polymers comprising the steps of:
(a) mixing a powder comprising copolymers of N-vinylpyrrolidone and N-vinylimidazole
with additional powders, the additional powders being selected from the group consisting
of aluminosilicate, citrate, silica, carbonate, bicarbonate, silicate, sulphate, phosphate,
water-soluble polymer and mixtures thereof, to form a powder premix; and
(b) mixing the premix with an aqueous binder in a high shear mixer to form free-flowing
particles.
[0016] The aqueous binder in step (b) is preferably an aqueous solution of polyamine N-oxide.
Again, less than 2 % by weight of surfactant is present.
[0017] A preferred process comprises the steps of (a) mixing from 5% to 25% by weight of
a powdered copolymer of N-vinylpyrrolidone and N-vinylimidazole with from 50% to 75%
by weight (on anhydrous basis) of sodium aluminosilicate to form a premix, and
(b) mixing the premix with from 5% to 25% by weight (on active basis) of an aqueous
solution of polyamine N-oxide in a high shear mixer to form free-flowing particles.
[0018] Optionally, the step of (c) drying the mixture of the premix and aqueous solution
of binder to form the free-flowing particles may also be included in the process.
[0019] The aluminosilicate, and any other salt present is usually fully hydrated prior to
the high shear mixer.
Detailed Description of the Invention
[0020] All of the percentages herein are by weight of the free-flowing powder unless otherwise
stated.
[0021] An essential ingredient of the free-flowing powders of the present invention is a
copolymer of N-vinylpyrrolidone and N-vinylimidazole dye transfer inhibiting agent.
Polymeric dye transfer inhibiting agents are normally incorporated into detergent
compositions in order to inhibit the transfer of dyes from colored fabrics onto fabrics
washed therewith. These polymers have the ability to complex or adsorb the fugitive
dyes washed out of dyed fabrics before the dyes have the opportunity to become attached
to other articles in the wash.
Especially suitable, further polymeric dye transfer inhibiting agents are polyamine
N-oxide polymers, polyvinylpyrrolidone polymers, polyvinyloxazolidones and polyvinylimidazoles
or mixtures thereof.
a) Polyamine N-oxide polymers
[0022] The polyamine N-oxide polymers suitable for use contain units having the following
structure formula :
- wherein
- P is a polymerisable unit, whereto the R-N-O group can be attached to or wherein the
R-N-O group forms part of the polymerisable unit or a combination of both. A is
![](https://data.epo.org/publication-server/image?imagePath=2002/45/DOC/EPNWB1/EP94302676NWB1/imgb0002)
-O-,-S-, -N- ; x is 0 or 1;
R are aliphatic, ethoxylated aliphatics, aromatic, heterocyclic or alicyclic groups
or any combination thereof whereto the nitrogen of the N-O group can be attached or
wherein the nitrogen of the N-O group is part of these groups.
[0023] The N-O group can be represented by the following general structures :
- wherein
- R1, R2, and R3 are aliphatic groups, aromatic, heterocyclic or alicyclic groups or
combinations thereof, x or/and y or/and z is 0 or 1 and wherein the nitrogen of the
N-O group can be attached or wherein the nitrogen of the N-O group forms part of these
groups.
[0024] The N-O group can be part of the polymerisable unit (P) or can be attached to the
polymeric backbone or a combination of both.
[0025] Suitable polyamine N-oxides wherein the N-O group forms part of the polymerisable
unit comprise polyamine N-oxides wherein R is selected from aliphatic, aromatic, alicyclic
or heterocyclic groups.
One class of said polyamine N-oxides comprises the group of polyamine N-oxides wherein
the nitrogen of the N-O group forms part of the R-group. Preferred polyamine N-oxides
are those wherein R is a heterocyclic group such as pyrridine, pyrrole, imidazole,
pyrrolidine, piperidine, quinoline, acridine and derivatives thereof.
Another class of said polyamine N-oxides comprises the group of polyamine N-oxides
wherein the nitrogen of the N-O group is attached to the R-group.
[0026] Other suitable polyamine N-oxides are the polyamine oxides whereto the N-O group
is attached to the polymerisable unit.
Preferred class of these polyamine N-oxides are the polyamine N-oxides having the
general formula (I) wherein R is an aromatic, heterocyclic or alicyclic groups wherein
the nitrogen of the N-0 functional group is part of said R group.
[0027] Examples of these classes are polyamine oxides wherein R is a heterocyclic compound
such as pyrridine, pyrrole, imidazole and derivatives thereof.
Another preferred class of polyamine N-oxides are the polyamine oxides having the
general formula (I) wherein R are aromatic, heterocyclic or alicyclic groups wherein
the nitrogen of the N-0 functional group is attached to said R groups.
[0028] Examples of these classes are polyamine oxides wherein R groups can be aromatic such
as phenyl.
[0029] Any polymer backbone can be used as long as the amine oxide polymer formed is water-soluble
and has dye transfer inhibiting properties. Examples of suitable polymeric backbones
are polyvinyls, polyalkylenes, polyesters, polyethers, polyamide, polyimides, polyacrylates
and mixtures thereof.
[0030] The amine N-oxide polymers which may be used in the present invention typically have
a ratio of amine to the amine N-oxide of 10:1 to 1:1000000. However the amount of
amine oxide groups present in the polyamine oxide polymer can be varied by appropriate
copolymerization or by appropriate degree of N-oxidation. Preferably, the ratio of
amine to amine N-oxide is from 2:3 to 1:1000000. More preferably from 1:4 to 1:1000000,
most preferably from 1:7 to 1:1000000. The polymers of the present invention actually
encompass random or block copolymers where one monomer type is an amine N-oxide and
the other monomer type is either an amine N-oxide or not. The amine oxide unit of
the polyamine N-oxides has a PKa < 10, preferably PKa < 7, more preferred PKa < 6.
[0031] The polyamine oxides can be obtained in almost any degree of polymerisation. The
degree of polymerisation is not critical provided the material has the desired water-solubility
and dye-suspending power.
Typically, the average molecular weight is within the range of 500 to 1000,000; preferably
from 1,000 to 50,000, more preferably from 2,000 to 30,000, most preferably from 3,000
to 20,000.
b) Copolymers of N-vinylpyrrolidone and N-vinylimidazole
[0032] The N-vinylimidazole N-vinylpyrrolidone polymers used in the present invention have
an average molecular weight range from 5,000-1,000,000, preferably from 20,000-200,000.
Highly preferred polymers for use in detergent compositions according to the present
invention comprise a polymer selected from N-vinylimidazole N-vinylpyrrolidone copolymers
wherein said polymer has an average molecular weight range from 5,000 to 50,000 more
preferably from 8,000 to 30,000, most preferably from 10,000 to 20,000.
The average molecular weight range was determined by light scattering as described
in Barth H.G. and Mays J.W. Chemical Analysis Vol 113,"Modern Methods of Polymer Characterization".
[0033] Highly preferred N-vinylimidazole N-vinylpyrrolidone copolymers have an average molecular
weight range from 5,000 to 50,000; more preferably from 8,000 to 30,000; most preferably
from 10,000 to 20,000.
[0034] The N-vinylimidazole N-vinylpyrrolidone copolymers characterized by having said average
molecular weight range provide excellent dye transfer inhibiting properties while
not adversely affecting the cleaning performance of detergent compositions formulated
therewith.
The N-vinylimidazole N-vinylpyrrolidone copolymer of the present invention has a molar
ratio of N-vinylimidazole to N-vinylpyrrolidone from 1 to 0.2, more preferably from
0.8 to 0.3, most preferably from 0.6 to 0.4 .
c) Polyvinylpyrrolidone
[0035] The detergent compositions of the present invention may also utilize polyvinylpyrrolidone
("PVP" having an average molecular weight of from about 2,500 to about 400,000, preferably
from about 5,000 to about 200,000, more preferably from about 5,000 to about 50,000,
and most preferably from about 5,000 to about 15,000. Suitable polyvinylpyrrolidones
are commercially available from ISP Corporation, New York, NY and Montreal, Canada
under the product names PVP K-15 (viscosity molecular weight of 10,000), PVP K-30
(average molecular weight of 40,000), PVP K-60 (average molecular weight of 160,000),
and PVP K-90 (average molecular weight of 360,000). PVP K-15 is also available from
ISP Corporation. Other suitable polyvinylpyrrolidones which are commercially available
from BASF Cooperation include Sokalan HP 165 and Sokalan HP 12. Polyvinylpyrrolidones
known to persons skilled in the detergent field; see for example EP-A-262,897 and
EP-A-256,696.
d) Polyvinyloxazolidone :
[0036] The detergent compositions of the present invention may also utilize polyvinyloxazolidone
as a polymeric dye transfer inhibiting agent. Said polyvinyloxazolidones have an average
molecular weight of from about 2,500 to about 400,000, preferably from about 5,000
to about 200,000, more preferably from about 5,000 to about 50,000, and most preferably
from about 5,000 to about 15,000.
e) Polyvinylimidazole :
[0037] The detergent compositions of the present invention may also utilize polyvinylimidazole
as polymeric dye transfer inhibiting agent. Said polyvinylimidazoles have an average
about 2,500 to about 400,000, preferably from about 5,000 to about 200,000, more preferably
from about 5,000 to about 50,000, and most preferably from about 5,000 to about 15,000.
[0038] A highly preferred component of the free-flowing powders of the present invention
is aluminosilicate.
[0039] Sodium aluminosilicate may take many forms. One example is crystalline aluminosilicate
ion exchange material of the formula
Na
z[(AlO
2)
z·(SiO
2)
y]·xH
2O
wherein z and y are at least about 6, the molar ratio of z to y is from about 1.0
to about 0.4 and z is from about 10 to about 264. Amorphous hydrated aluminosilicate
materials useful herein have the empirical formula
M
z(zAlO
2·ySiO
2)
wherein M is sodium, potassium, ammonium or substituted ammonium, z is from about
0.5 to about 2 and y is 1, said material having a magnesium ion exchange capacity
of at least about 50 milligram equivalents of CaCO
3 hardness per gram of anhydrous aluminosilicate. Hydrated sodium Zeolite A with a
particle size of from about 1 to 10 microns is preferred.
[0040] The aluminosilicate ion exchange builder materials herein are in hydrated form and
contain from about 5% to about 28% of water by weight if crystalline, and potentially
even higher amounts of water if amorphous. Highly preferred crystalline aluminosilicate
ion exchange materials contain from about 15% to about 22% water in their crystal
matrix. The crystalline aluminosilicate ion exchange materials are further characterized
by a particle size diameter of from about 0.1 micron to about 10 microns. Amorphous
materials are often smaller, e.g., down to less than about 0.01 micron. Preferred
ion exchange materials have a particle size diameter of from about 0.2 micron to about
4 microns. The term "particle size diameter" herein represents the average particle
size diameter by weight of a given ion exchange material as determined by conventional
analytical techniques such as, for example, microscopic determination utilizing a
scanning electron microscope. The crystalline aluminosilicate ion exchange materials
herein are usually further characterized by their calcium ion exchange capacity, which
is at least about 200 mg equivalent of CaCO
3 water hardness/g of aluminosilicate, calculated on an anhydrous basis, and which
generally is in the range of from about 300 mg eq./g to about 352 mg eq./g. The aluminosilicate
ion exchange materials herein are still further characterized by their calcium ion
exchange rate which is at least about 2 grains Ca
++/gallon/minute/gram/gallon of aluminosilicate (anhydrous basis), and generally lies
within the range of from about 2 grains/gallon/minute/gram/gallon to about 6 grains/gallon/minute/gram/gallon,
based on calcium ion hardness. Optimum aluminosilicate for builder purposes exhibit
a calcium ion exchange rate of at least about 4 grains/gallon/minute/gram/gallon.
[0041] The amorphous aluminosilicate ion exchange materials usually have a Mg
++ exchange of at least about 50 mg eq. CaCO
3/g (12 mg Mg
++/g) and a Mg
++ exchange rate of at least about 1 grain/gallon/minute/gram/gallon. Amorphous materials
do not exhibit an observable diffraction pattern when examined by Cu radiation (1.54
Angstrom Units).
[0042] Aluminosilicate ion exchange materials useful in the practice of this invention are
commercially available. The aluminosilicates useful in this invention can be crystalline
or amorphous in structure and can be naturally occurring aluminosilicates or synthetically
derived. A method for producing aluminosilicate ion exchange materials is discussed
in U.S. Pat. No. 3,985,669, Krummel et al., issued Oct. 12, 1976. Preferred synthetic
crystalline aluminosilicate ion exchange materials useful herein are available under
the designations Zeolite A, Zeolite B, Zeolite MAP and Zeolite X. In an especially
preferred embodiment, the crystalline aluminosilicate ion exchange material has the
formula
Na
12[(AlO
2)
12(SiO2)
12]·xH
2O
wherein x is from about 20 to about 30, especially about 27 and has a particle size
generally less than about 5 microns.
[0043] The aluminosilicate which may be used in the present invention may, optionally, be
fully or partially replaced by other particulate materials such as citrate, silicate,
carbonate, bicarbonate, sulphate, phosphate, silica and mixtures thereof.
[0044] Water soluble polymers, in addition to the polymeric dye transfer inhibiting agents
listed above may be incorporated into the free-flowing powders of the present invention.
Typical examples of such polymers are sodium carboxy-lower alkyl celluloses, sodium
lower alkyl celluloses and sodium hydroxy-lower alkyl celluloses, such as sodium carboxymethyl
cellulose, sodium methyl cellulose and sodium hydroxypropyl cellulose, polyvinyl alcohols
(which often also include some polyvinyl acetate), polyacrylamides, polyacrylates
and various copolymers, such as those of maleic and acrylic acids. Molecular weights
for such polymers vary widely but most are within the range of 2,000 to 100,000.
[0045] Polymeric polycarboxylate builders are set forth in U.S. Patent 3,308,067, Diehl,
issued March 7, 1967. Such materials include the water-soluble salts of homo-and copolymers
of aliphatic carboxylic acids such as maleic acid, itaconic acid, mesaconic acid,
fumaric acid, aconitic acid, citraconic acid and methylenemalonic acid.
[0046] The free-flowing powders of the present invention comprise less than 2% by weight
of surfactants, and preferably do not contain any surfactants. However, where surfactants
are incorporated, anionic, nonionic, cationic, amphoteric, and zwitterionic surfactants
may be used.
Process
[0047] The preferred process of the present invention comprises the steps of:
(a) mixing a powder comprising copolymers of N-vinylpyrrolidone and N-vinylimidazole
with additional powders, to form a powder premix; and
(b) mixing the premix with an aqueous binder in a high shear mixer to form free-flowing
particles.
[0048] The aqueous binder in step (b) is preferably an aqueous solution of a polyamine N-oxide
polymer, preferably poly(4-vinyl pyridine N-oxide).
[0049] High shear mixers suitable for use in the present invention include the Fukae
R FS-G series manufactured by Fukae Powtech Kogyo Co., Japan; this apparatus is essentially
in the form of a bowl-shaped vessel accessible via a top port, provided near its base
with a stirrer having a substantially vertical axis, and a cutter positioned on a
side wall. The stirrer and cutter may be operated independently of one another and
at separately variable speeds. The vessel can be fitted with a cooling jacket or,
if necessary, a cryogenic unit.
[0050] Other similar mixers found to be suitable for use in the process of the invention
include Diosna
R V series ex Dierks & Söhne, Germany; and the Pharma Matrix
R ex T K Fielder Ltd., England. Other mixers believed to be suitable for use in the
process of the invention are the Fuji
R VG-C series ex Fuji Sangyo Co., Japan; and the Roto
R ex Zanchetta & Co srl, Italy.
[0051] Other preferred suitable equipment can include Eirich
R, series RV, manufactured by Gustau Eirich Hardheim, Germany; Lödige
R, series FM for batch mixing, series Baud KM for continuous mixing/agglomeration,
manufactured by Lödige Machinenbau GmbH, Paderborn Germany; Drais
R T160 series, manufactured by Drais Werke GmbH, Mannheim Germany; and Winkworth
R RT 25 series, manufactured by Winkworth Machinery Ltd., Berkshire, England. A particularly
preferred combination of mixers is a Lödige
R CB mixer, followed in series by a Lödige
R KM mixer.
[0052] The Littleford Mixer, Model #FM-130-D-12, with internal chopping blades and the Cuisinart
Food Processor, Model #DCX-Plus, with 7.75 inch (19.7 cm) blades are two examples
of suitable mixers. Any other mixer with fine dispersion mixing and granulation capability
and having a residence time in the order of 0.1 to 10 minutes can be used. The "turbine-type"
impeller mixer, having several blades on an axis of rotation, is preferred. The invention
can be practiced as a batch or a continuous process.
[0053] After the mixing step, an additional drying step may be employed. A continuous fluidised
bed dryer is suitable for this.
[0054] The particle size of the free-flowing particles of the present invention may also
be important, particularly with regard to the tendency to form gel upon contact with
water which has an adverse effect upon product dispensing. It is preferred that small
particles, especially "fines" are avoided. Preferably the mean particle size is greater
than 300 micrometers, preferably greater than 450 micrometers, and most preferably
about 550 micrometers. Average particle size may be conveniently calculated by splitting
the product into a series of fractions on a series of sieves of decreasing mesh aperture,
and measuring the weight of each fraction.
Finished Product Compositions
[0055] It is expected that the free-flowing particles of the present invention will be added
to other granular components to give a finished product composition. Other granular
components may be prepared by any suitable means including spray drying, spray cooling,
and agglomeration. Compact detergent compositions (i.e. those having a bulk density
of at least 600 g/l) according to the present invention typically comprise from 0.001%
to 10 %, preferably from 0.01% to 2%, more preferably from 0.05% to 1% by weight of
a polymeric dye transfer inhibiting agents.
Bulk density
[0056] All the bulk densities referred to herein are measured by the non-compacted repour
cup density method. This method uses an apparatus consisting of a funnel mounted above
a 500 ml cup, the distance from the base of the funnel to the top of the cup being
50mm. The cup is filled to overflowing with product from the funnel (through an aperture
of 40mm diameter). Without tapping the cup, excess product is removed by scraping
away excess by means of a straight edge across the top of the cup. The net weight
of product is then measured and recorded, and bulk density is calculated according
to the volume of the cup.
Examples
[0057] In the examples the following abbreviations have been used:
- PVPVI
- Copolymers of N-vinylpyrrolidone and N-vinylimidazole having a molecular weight of
10000.
- PVNO
- Poly (4-vinyl pyridine N-oxide) having a molecular weight of 10000.
Example 1
[0058] The following premix was prepared in a batch vertomix blender:
Zeolite 4A |
80 parts by weight |
PVPVI |
10.5 parts by weight |
The premix was transferred on a continuous basis by means of a feeding screw to the
inlet port of a Loedige® CB high shear mixer operated at 1700 rpm. An aqueous solution
of PVNO (having an active content of 35%) was pumped to spray nozzles in the mixer.
At the same time water was pumped to additional spray nozzles in the mixer. The components
being added in the following ratio:
Premix |
90.5 parts by weight |
PVNO Solution |
30 parts by weight |
Water |
8 parts by weight |
The wet powder at the exit port of the high shear mixer was transferred directly
into the inlet port of a Loedige® KM mixer operating at 140 rpm.
[0059] Further agglomeration of the wet powder took place in the second mixer to form a
wet agglomerate. With the exit gate of the second mixer fully open, wet agglomerates
were transferred by a vibrating tube into a continuous fluidised bed supplied with
air at 120°C.
[0060] The resulting free-flowing powder had a bulk density of 700 g/l and a composition
of:
Zeolite (anhydrous basis) |
65% |
PVPVI |
10.5% |
PVNO |
10.5% |
Water |
9% |
Miscellaneous * |
5% |
(*miscellaneous are principally impurities brought into the process with the zeolite). |
Example 2
[0061] The process of example 1 was repeated except the premix was prepared in a continuous
ribbon blender, and subsequently conveyed to the inlet of the Loedige® CB mixer using
a pneumatic conveying system, and a feeding screw. The Loedige® CB mixer was operated
at 1000 rpm.
Example 3
[0062] The process of example 1 was repeated with a 10 cm weir in the fluidised bed. The
weir had the effect of increasing the residence time in the fluidised bed to 5 to
10 minutes.
Example 4
[0063] The premix of example 1 was prepared in a high shear Eirich® mixer. The PVNO solution
was then added directly to the Eirich® mixer resulting in agglomeration of the premix
to form wet granules. The granules were then transferred to a batch fluidised bed
supplied with air at 100°C and dried.
1. Freifließendes Pulver mit einer Schüttdichte von mindestens 600 g/l, umfassend:
(a) 20 bis 95 Gew.-% (auf wasserfreier Basis) eines Reinigungsmittelbestandteils,
gewählt aus der Gruppe, bestehend aus Aluminosilicat, Citrat, Silica, Carbonat, Bicarbonat,
Silicat, Sulfat, Phoshpat, wasserlösliches Polymer und Mischungen hiervon;
(b). 5 bis 50 Gew.-% eines Copolymeren von N-Vinylpyrrolidon und N-Vinylimidazol mit
einem Durchschnittsmolekulargewichtsbereich von 5.000 bis 1.000.000 und einem Molverhältnis
von N-Vinylimidazol zu N-Vinylpyrrolidon von 1 bis 0,2; und
dadurch gekennzeichnet, daß der Gehalt an Tensid weniger als 2 Gew.-% beträgt.
2. Freifließendes Pulver nach Anspruch 1, umfassend:
(a) 50 bis 75 Gew.-% (auf wasserfreier Basis) Aluminosilicat;
(b) 10 bis 30 Gew.-% einer Mischung aus Polyamin-N-oxid und einem Copolymer von N-Vinylpyrrolidon
und N-Vinylimidazol.
3. Freifließendes Pulver nach Anspruch 2, umfassend eine Mischung aus Polyamin-N-oxid
(i) und einem Copolymer von N-Vinylpyrrolidon und N-Vinylimidazol (ii), wobei das
Verhältnis von (i) zu (ii) 5:1 bis 1:5 beträgt, und vorzugsweise etwa 1:1 ist.
4. Verfahren zur Herstellung freifließender Teilchen, umfassend hygroskopische Pulver
von Polymeren, umfassend die Schritte:
(a) Mischen eines pulverförmigen Polymeren mit zusätzlichen Pulvern, wobei die zusätzlichen
Pulver aus der Gruppe gewählt sind, bestehend aus Aluminosilicat, Citrat, Silica,
Carbonat, Bicarbonat, Silicat, Sulfat, Phosphat, wasserlösliches Polymer und Mischungen
hiervon, um eine Pulvervormischung zu bilden;
(b) Vermischen der Vormischung mit einer wäßrigen Lösung eines Bindemittels in einem
Hochschermischer, um freifließende Teilchen zu bilden.
dadurch gekennzeichnet, daß das pulverförmige Polymer in Schritt (a) ein Copolymer von N-Vinylpyrrolidon und
N-Vinylimidazol mit einem Durchschnittsmolekulargewichtsbereich von 5.000 bis 1.000.000
und einem Molverhältnis von N-Vinylimidazol zu N-Vinylpyrrolidon von 1 bis 0,2 umfaßt,
die wäßrige Lösung eines Bindemittels in Schritt (b) eine wäßrige Lösung eines Polyamin-N-oxid-Polymeren
ist, und weniger als 2% Tensid in den Teilchen vorliegen.
5. Verfahren nach Anspruch 4, wobei das pulverförmige Polymer in Schritt (a) ein Copolymer
von N-Vinylpyrrolidon und N-Vinylimidazol ist, und die wäßrige Lösung eines Bindemittels
in Schritt (b) eine wäßrige Lösung von Polyamin-N-oxid ist.
6. Verfahren nach Anspruch 5, umfassend die Schritte:
(a) Mischen von 5 bis 25 Gew.-% eines pulverförmigen Copolymeren von N-Vinylpyrrolidon
und N-Vinylimidazol mit 50 bis 75 Gew.-% (auf wasserfreier Basis) Natriumaluminosilicat,
zur Bildung einer Vormischung, und
(b) Vermischen der Vormischung mit 5 bis 25 Gew.-% (auf Wirkstoffbasis) einer wäßrigen
Lösung von Polyamin-N-oxid in einem Hochschermischer zur Bildung freifließender Teilchen.
7. Verfahren nach mindestens einem der Ansprüche 4 bis 6, umfassend weiterhin den Schritt
(c) Trocknen der Mischung aus der Vormischung und der wäßrigen Bindemittellösung zur
Bildung der freifließenden Teilchen.
8. Verfahren nach Anspruch 4, wobei das Aluminosilicat und irgendein anderes vorliegendes
Salz vor dem Hochschermischen vollständig hydratisiert wird.