Note: Descriptions are shown in the official language in which they were submitted.
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DETERGENT COMPONENT OR COMPOSITION WITH PROTECTIVE COATING
The present invention relates to the field of coated
particulate detergent components or compositions.
It is known that the flow properties of granular detergents
can be improved by "dusting" them with finely divided
particulates, such as zeolite. US-A-3 868 336 discloses
detergent compositions dusted with from 0.5$ to 15o by
weight of water-insoluble flow-promoting agents. However,
dusting with finely divided particulates does not provide
any benefit for detergent dispensing, it can also make the
final detergent product dusty, and it does not always
provide adequate improvements in the flow properties.
Other coating agents, applied as liquids, melts or
solutions are also known in the field of detergents.
GB-A-1 395 006, published on 21st May 1975, discloses
cellulosic polymers as coating agents for detergent
components. Sucrose and glucose are also disclosed therein,
as plasticizers with dextrin. However cellulosic polymers
and sugars are nowhere disclosed in combination as coating
agents for detergent components.
The disadvantage of coating a detergent with cellulosic
polymer on its own is that the film formed is slow to dry,
and can form a coating that is sticky.
Mixtures of cellulosic polymers and sugars are known
coating agents in the pharmaceutical field.
JP-51 123 815, published 29th October 1976, and EP-A-0 551
700, published on 21st July 1993 both disclose combinations
of cellulosic polymer and sugars as coating agents for
pharmaceutical products, but there is no suggestion that
these coatings are suitable for use with detergents.
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The object of the present invention relates to the
application of certain coatings to particulate detergent
components or compositions to improve free-flow
properties, improve dispensing, avoid dust formation and
improve stability of storage sensitive materials.
A further object of the present invention is to provide a
fast-drying coating which forms a continuous film around
the particles of the detergent component or composition.
Summary of the Invention
The object of the invention is achieved by a two-step
coating process, wherein the first coating step comprises
the process of mixing the detergent composition or
component with a finely divided particulate material which
is preferably aluminosilicate, and the second coating step
comprises the process of applying a coating agent.
Suitable coating agents comprise from 5% to 95%,
preferably from 10% to 60% by weight of cellulosic
polymer; from 5% to 95%, preferably from 60% to 90% by
weight of sugar; and optionally, from 0% to 30% by weight
of plasticizer.
Preferred detergent components include nonionic
surfactant, in particular polyhydroxy fatty acid amide;
and bleach activators.
In one particular embodiment there is provided a
particulate detergent composition or component comprising
a detersive surfactant system and optionally adjunct
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materials selected from the group consisting of builders,
chelants, bleach, bleach activators, enzymes, enzyme
stabilizers, soil release agents, brightener, suds
suppressor, fabric softener, antiredeposition agents and
mixtures thereof; the detergent composition or component
being coated by a two-step coating process, wherein the
first coating step comprises the process of mixing the
detergent composition or component with a finely divided
particulate material selected from the group consisting of
aluminosilicates, talc, silica and clays, and
characterized in that the second coating step comprises
the process of applying a coating agent, the coating agent
comprising: (i) from 5% to 95% by weight of cellulosic
polymer; (ii) from 5% to 95% by weight of a sugar.
Detailed Description of the Invention
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The term "cellulosic polymer" as used herein means polymers
that are built up from derivatives of cellulose. Cellulose
is a polysaccharide made from ~i-D-glucose units linked
together. In the derivatives one or more of the hydroxyl
groups are replaced by other groups e.g. methyl, ethyl,
propyl.
Preferred cellulosic polymers include methyl cellulose,
ethyl cellulose, hydroxymethyl cellulose, hydroxyethyl
cellulose, hydroxypropyl cellulose, methylhydroxymethyl
cellulose, methylhydroxyethyl cellulose,
methylhydroxypropyl cellulose and ethyl hydroxyethyl
cellulose.
The term "sugar" as used herein is a generic term for a
class of carbohydrates which are usually crystalline and
sweet by nature, and which are water soluble. Sugars are
formed form glucose and fructose units which are sugars in
their own right. Preferred sugars include glucose,
fructose, galactose, sucrose, maltose, lactose, sorbitol,
manitol, rafinose, trehalose.
The term "plasticizer" as used herein is a material that is
added to the original material for the purpose of softening
the original material, and make it more flexible. Preferred
plastisizers~include polyethylene glycol having a molecular
weight of between 200 and 20000, polypropylene glycol,
glycerol, triacetin
The second coating agent may be applied in any conventional
coating apparatus. Suitable apparatus include pan coater;
rotating drum continuous coater; spray fluidised granular,
or spray fluidised continuous belt. In a particular
embodiment of the present invention the components of the
second coating agent are dissolved or dispersed in a
suitable solvent or carrier medium. A preferred solvent is
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water, and an aqueous solution may be prepared which is
typically S~ to 40o solids.
The solution or dispersion may then be sprayed on to the
detergent component or composition. The proportion of the
second coating agent needed to provide a suitable coating
layer depends on various parameters, such as the surface
characteristics of the detergent component or composition,
and will be easily determined by experiment. Preferably the
second coating agent is from 0.1o to 30$ of the finished
product, more preferably, from 1~ to 50, and most
preferably about 20.
In the present invention, the detergent component or
composition is coated with a finely divided particulate
material prior to coating with the second coating agent.
The detergent component or composition is coated with a
first coating agent comprising up to 35%, preferably from
1~ to 20~ by weight of finely divided particulate material
prior to the application of the second coating agent. The
first coating agent has two purposes. Firstly it allows
the detergent particles to be separated (if they are
sticky) so that each one can be fully coated. Secondly it
gets combined into the second coating agent and adds
additional structure to the coating.
Finely divided particulate materials useful herein include
aluminosilicates having the empirical formula:
Mz ( zA102 ) y ] ~ x H20
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wherein z and y are integers of at least 6, the molar ratio
of z to y is in the range from 1.0 to about 0.5, and x is
an integer from about 15 to about 264.
Usefulaluminosilicate ion exchange materials are
commercially available. These aluminosilicates 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 disclosed in US-A-3 985 669, Krummel et al, issued
October 12, 1976. Preferred synthetic crystalline
aluminosilicate ion exchange materials useful herein are
available under the designations zeolite A, zeolite P(B),
zeolite MAP, zeolite X and zeolite Y. In an especially
preferred embodiment, the crystalline aluminosili~cate ion
exchange material has the formula .
Nal2 [ (A102) 12 (Si02) 12 ] ~ x H20
wherein x is from about 20 to about 30, especially about
27. This material is known as zeolite A. Dehydrated
zeolites (x=0-10), and "overdried" zeolites (x=10-20) may
also be used herein. The "overdried" zeolites are
particularly useful when a low moisture environment is
required, for example to improve stability of detergent
bleaches such as perborate and percarbonate. Preferably,
the aluminosilicate has a particle size of about 0.1-10
micrometers in diameter. Preferred ion exchange materials
have a particle size diameter of from about 0.2 micrometers
to about 4 micrometers. 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 zeolite A materials herein are
usually further characterized by their calcium ion exchange
capacity, which is at least about 200 mg equivalent of
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CaC03 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 zeolite
A materials herein are still further characterized by their
calcium ion exchange rate which is at least about 2 grains
Ca++/gallon/minute/gram/gallon (0.13g
Ca++/litre/minute/gram/litre) of aluminosilicate (anhydrous
basis), and generally lies within the range of from about 2
grains/gallon/minute/gram/gallon(0.13g
Ca++/litre/minute/gram/litre) to about 6
grains/gallon/minute/gram/gallon (0.398
Ca++/litre/minute/gram/litre), 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 (0.268
Ca++/litre/minute/gram/litre).
Other finely divided particulate materials include talc,
silica and bentonite, as well as other clays.
Particulate Detergent Components or Compositions
Detergent components or compositions are conventionally
processed into particulate form in one of a number of ways.
Spray-drying is one such process which has been widely
practised for may decades. More recently dry
neutralisation, agglomeration, extrusion, granulation in
fluidised beds, flaking, encapsulation, grilling,
pastillation and other processes have also been used.
Detergent compositions and components typically comprise
surfactants, builders, chelants, bleach, bleach activators,
enzymes, enzyme stabilisers, soil release agents,
brightener, suds suppressor, fabric softener,
antiredeposition agents and mixtures of these. The present
invention is particularly suitable for use with nonionic or
cationic surfactants, or with bleach activators.
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Preferred nonionic surfactants for use in the present
invention include two families of nonionics which have been
found to be particularly useful. These are nonionic
surfactants based on alkoxylated (especially ethoxylated)
alcohols, and those nonionic surfactants based on amidation
products of fatty acid esters and N-alkyl polyhydroxy
amine. The amidation products of the esters and the amines
are generally referred to herein as polyhydroxy fatty acid
amides. Particularly useful in the present invention are
mixtures comprising two or more nonionic surfactants
wherein at least one nonionic surfactant is selected from
each of the groups of alkoxylated alcohols and the
polyhydroxy fatty acid amides.
Suitable nonionic surfactants include compounds produced by
the condensation of alkylene oxide groups (hydrophilic in
nature) with an organic hydrophobic compound, which may be
aliphatic or alkyl aromatic in nature. The length of the
polyoxyalkylene group which is condensed with any
particular hydrophobic group can be readily adjusted to
yield a water-soluble compound having the desired degree of
balance between hydrophilic and hydrophobic elements.
Particuvarly preferred for use in the present invention are
nonionic surfactants such as the polyethylene oxide
condensates of alkyl phenols, e.g., the condensation
products of alkyl phenols having an alkyl group containing
from about 6 to 16 carbon atoms, in either a straight chain
or branched chain configuration, with from about 4 to 25
moles of ethylene oxide per mole of alkyl phenol.
Preferred nonionics are the water-soluble condensation
products of aliphatic alcohols containing from 8 to 22
carbon atoms, in either straight chain or branched
configuration, with an average of up to 25 moles of
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ethylene oxide per more of alcohol. Particularly preferred
are the condensation products of alcohols having an alkyl
group containing from about 9 to 15 carbon atoms with from
about 2 to 10 moles of ethylene oxide per mole of alcohol
and condensation~products of propylene glycol with ethylene
oxide. Most preferred are condensation products of alcohols
having an alkyl group containing from about 12 to 15 carbon
atoms with an average of about 3 moles of ethylene oxide
per mole of alcohol.
It is a particularly preferred embodiment of the present
invention that the nonionic surfactant system also includes
a polyhydroxy fatty acid amide component.
Polyhydroxy fatty acid amides may be~.produced by reacting a
fatty acid ester and an N-alkyl polyhydroxy amine. The
preferred amine for use in the present invention is N-(R1)-
CHZ(CHZOH)4-CH2-OH, where Rl is typically a alkyl, e.g.
methyl group: and the preferred ester is a Cla-Cao fatty
acid methyl ester.
Methods of manufacturing polyhydroxy fatty acid amides have
been described in WO 92 6073, published on 16th April,
1992. ?ltis application describes the preparation of
polyhydroxy fatty acid amides in the presence of solvents.
In a highly preferred embodiment of the invention N-methyl
glucamine is reacted with a C12-Czo methyl ester.
Other nonionic surfactants which may be used as components
of the surfactant systems herein include ethoxylated
nonionic surfactants, glycerol ethers, glucosamides,
glycerol amides, glycerol esters. fatty~acids, fatty acid
esters, fatty amides, alkyl polyglucosides, alkyl
polyglycol ethers, polyethylene glycols, ethoxylated alkyl
phenols and mixtures thereof.
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The present invention is particularly useful with bleach
activators. For hygiene reasons, the inhalation of many
' bleach activators should be avoided, so dusty products
should be avoided. The present invention provides a means
for minimising or eliminating dust formation by providing
an effective coating.
Particularly suitable bleach activators are caproyl
oxybenzene sulfonate; N,N,N1N1 tetra acetylated compounds;
benzoyloxybenzene sulphonate; benzoyl caprolactam; and
mixtures thereof. Most suitable bleach activators are (6-
octanamido-caproyl)oxybenzenesulfonate, (6-nonanamido-
caproyl)oxy benzene sulfonate, (6-decanamido-
caproyl)oxybenzenesulfonate, and mixtures thereof.
Example 1
$ by weight
Poly hydroxy fatty acid amide 4g
Nonionic surfactant (AE5) 22
Hydrogenated fatty acid
First coating agent - Zeolite A 20
Second coating agent 2
A molten mixture consisting of the nonionic surfactants
polyhydroxy fatty acid amide, ethoxylated alcohol and the
hydrogenated fatty acid was prepared. Micropastilles of the
molten mixture were then made by forming drops of the
molten material on a cold steel belt, where they solidify.
Apparatus for carrying out micropastillation is
commercially available from Sandvik.
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The micropastilles were then coated first with the zeolite
(10~ by weight), and subsequently coated with the coating
agent which was an aqueous solution with a solids content
of 15~, the solids content comprising hydroxy propyl methyl
cellulose (35 parts), lactose (45 parts), and triacetin (20
parts).
The first coating of zeolite was applied in a concrete
mixer to ensure good distribution of the flow aid. The
second coating agent was applied by spraying the aqueous
coating in a spray fluid bed granulator. The aqueous
coating was sprayed onto the particles, and warm air was
used to dry off the excess water.
Example 2
- ~ by weight
NACA-OBS 68
Citric acid 10
Anionic surfactant (AE3S) 5
Malefic-acrylic copolymer 5
Water 2
First coating agent - Zeolite A 5
Second coating agent 5
NACA-OBS is nonyl amido caproyl oxy benzene sulphonate
which is a bleach activator.
AE3S is alkyl ether sulphate (with 3 EO groups per
molecule).
A detergent component comprising the bleach activator,
citric acid, anionic surfactant, copolymer and water was
prepared by mixing the dry materials and binders and
passing the mixture through an extruder forming noodles of
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materials. These noodles are allowed to drop into a
spheroniser (a Marumeriser~ having a rotating bowl with a
friction plate) which shapes beads of the desired size.
The beads were then coated first with the zeolite (5$ by
weight), and subsequently coated with the second coating
agent which was an aqueous solution with a solids content
of 15$, the solids content comprising hydroxy propyl methyl
cellulose (35 parts), lactose (45 parts), and triacetin (20
parts). The coating was applied in a fluid bed granulator.
Example 3
~ by weight
Poly hydroxy fatty acid amide 6
Nonionic surfactant (AE5) 1g
Hydrogenated fatty acid 3
Glycerol Tristearate
Zeolite A 56
Carbonate 6
First coating agent - Zeolite A 5
Second coating agent 5
A molten mixture consisting of the nonionic surfactants
polyhydroxy fatty acid amide, ethoxylated alcohol,
hydrogenated fatty,acid and glycerol tristearate was
prepared. This paste was cooled and agglomerated in a CB
Loedige~ with the zeolite and carbonate. The finished
agglomerates were dusted with additional zeolite in a KM
Loedige~.
The agglomerates were subsequently coated with the second
coating agent which was an aqueous solution with a solids
content of 40~, the solids content comprising hydroxy
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propyl methyl cellulose (10 parts), lactose (45 parts), and
sucrose (45 parts).
The second coating agent was applied by spraying the
aqueous coating in a spray fluid bed granulator. The
aqueous coating was sprayed onto the particles, and warm
air was used to dry off the excess water.
