Note: Descriptions are shown in the official language in which they were submitted.
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WO 96/34079 PCT/US96/04224
PROCESS FOR PRODUCING GRANULAR DETERGENT COMPONENTS OR
COMPOSITIONS
~ The present invention relates to a process for the
continuous preparation of a granular detergent composition
or component having a high bulk density and good flow
properties. In such compositions and components it is known
to use crystalline Zeolite A which is a water-insoluble,
crystalline material well-known in the detergent art as a
builder which is particularly suited to removing cations
such as calcium and magnesium from hard water.
Crystalline Zeolite A is a very finely divided powder. It
has been common practice to process the finely divided
powder into the form of larger granules (typically 400 to
1000 micrometers) before incorporation into finished
products, especially finished detergent compositions.
Various granulation processes are known including spray
drying and agglomeration. Conventional agglomeration
processes in which Zeolite A is used as one of the
components have long been known in the prior art .
GB2005715, published on 25th April 1979 describes an
° agglomeration process based upon Zeolite A. The Zeolite A
is agglomerated along with carbonate/bicarbonate to make
nonionic surfactant agglomerates.
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2
W093/25378, published on 23rd December 1993, discloses a
process for making granular detergents comprising Zeolite
A. The Zeolite A is agglomerated with a high active, .
neutralised surfactant paste in a high speed mixer and a
moderate speed mixer/agglomerator to make anionic
surfactant agglomerates.
One of the factors which limits the surfactant activity of
the prior art mentioned above is the capacity of Zeolite A
to absorb liquid organic materials. It has been suggested
that replacing Zeolite A by Zeolite P (specifically Zeolite
MAP) could address this problem .
EP521635, published on 7th January 1993, discloses granular
detergents made using from 10~ to 100 of Zeolite MAP.
Zeolite MAP has a different chemical composition to Zeolite
A. In Example 1 of this patent application it is reported
that the oil absorbing capacity of Zeolite MAP is 41.6
ml/100g, and that this is higher than measured samples of
Zeolite A for which it is 26 to 35.5 ml/100g.
However modifying the chemical structure of conventional
crystalline Zeolite A (i.e. modifying the stoichiometric
ratios of Si, A1, Na, O, H) is not always desirable because
other properties and characteristics of the Zeolite are
necessarily affected.
The object of the invention is to provide a granulation
v
process for making granular detergents which incorporates
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R'O 96/34079 PCT/LTS96/04224
3
highly absorbent crystalline Zeolite into granular
agglomerates, without losing any of the builder
capabilities, especially calcium exchange capacity and
calcium exchange rate.
According to the invention this object is achieved by using
a crystalline Zeolite which consists essentially of Zeolite
A, P, X, (or mixtures thereof) and Zeolite HS (Hydroxy
Sodalite). This is in marked contrast to prior art zeolites
in which zeolite HS has been regarded as an impurity, and
its formation ha.s been avoided. The zeolite of the present
invention has modified physical characteristics (i.e.
crystallinity, surface area characteristics, moisture level
etc.) which in turn promotes greater ease and flexibility
in processing during the manufacture of detergent powders.
The basic chemical structure of the zeolite is unchanged,
hence the excellent builder properties of zeolite may still
be utilised.
It is a further object of the present invention to provide
a granulation process for making granular detergents having
improved processability, and amount of oversize particles
(or "lumps") being formed in the process being reduced.
Summary of the Invention
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4
In one embodiment there is provided a process for the
preparation of a granular detergent composition or component
having a bulk density greater than 650 g/1, which comprises
the step of dispersing a liquid binder throughout a powder
stream in a high speed mixer to form granular agglomerates,
wherein the powder stream comprises a powder consisting
essentially of crystalline zeolite P and crystalline zeolite
HS.
It is preferred that the ratio of zeolite P to crystalline
zeolite HS is from 1:1 to 99:1, preferably from 3:1 to 20:1,
and that the powder has an oil absorbing capacity of at least
40 ml/100 g, more preferably at least 45 ml/100 g, most
preferably at least 50 ml/100 g.
In a preferred embodiment of the invention the granular
agglomerates are formed by mixing in the high speed mixer for
a residence time of from about 2 seconds to about 30 seconds,
followed by the step of
further mixing in a moderate speed mixer/agglomerator for a
residence time through the moderate speed mixer of less than
about 5 minutes, preferably less than about 2 minutes, in
which, optionally, a finely divided powder may be added.
The granular detergent composition or component comprises from
20% to 80% by weight, preferably from 20% to 70o by weight, of
a powder of the crystalline zeolite and at least about 20% by
weight, preferably at least about 30% by weight, of a
surfactant.
In different embodiments of the invention the liquid binder is
a surfactant paste, an organic polymer or silicone oil.
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Surfactant paste may comprise anionic, nonionic, cationic,
amphoteric, zwitterionic surfactants, and mixtures thereof;
anionic and/or nonionic surfactants being most preferred. The
paste should comprise at least loo by weight of a neutralized
anionic surfactant having a viscosity of at least 10000 mPas.
In a preferred embodiment the paste may comprise at least 70%
by weight of surfactant.
Detailed Description of the Invention
Granulation in the context of the present invention is defined
as a process of making a granulated product which is an
agglomerate of particles that itself behaves as a particle
(according to S.A. Kuti, "Agglomeration - The Practical
Alternative", published in Journal American Oil Chemists'
Society, Volume 55, January 1978). The granular agglomerate is
defined herein as the product of such a granulation process.
Kuti goes on to state that "the agglomerate is usually formed
by blending solids with liquids that serve as adhesive agents.
But a lump-free liquid-solids blend is often a difficult task
to produce."
In the present invention the "solids" referred to by Kuti will
comprise crystalline zeolite having certain physical
characteristics to be defined in more detail below. It has now
been found that this choice of "solids" contributes greatly to
fulfilling the task of producing a lump-free liquid-solids
blend.
The essential component of the granular agglomerate of the
present invention is crystalline Zeolite HS of the formula:
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WO 96/34079 PCT/L1S96/04224
6
(Na20) . (A12O3) . x (Si02) . wH20
wherein x is 2, and w is about 2.5 (From D.W. Breck,
"ZCVllte llVlel.ular 7i~vC5°°, - Uoilil W~l~y- & -JOn~, N2w
xOL'k,
1974, page 155). Zeolite HS is also known as Zeolite G,
Sodalite Hydrate and Hydroxy Sodalite.
The ideal unit cell composition for sodalite hydrate is:
Na6 A106 Si6 024 ~ 8 H20 (Breck, page 269)
If NaOH is intercalated during synthesis, the composition
varies according to .
Na6 A106 Si6 024 - xNaOH (8-2x) H20 (Breck, page 272)
since one NaOH replaces two water molecules. Sodium hydrate
has been observed to adsorb water after dehydration.
Breck also says that °'silica rich zeolite A appears to
crystallise well in a period of 1 hour which is followed by
rapid conversion in many instances to hydroxysodalite. This
is to be expected from sodium rich compositions of this
type. The formation of hydroxysodalite was also accelerated
when various anions were added to the gel compositions."
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7
For the purposes of the present invention it is necessary
to control reaction conditions such that crystalline
zeolite A (or P, X) is formed in the required ratio to
zeolite HS. Preferred ways of doing this are to use sodium-
rich gels in the zeolite formation and to carefully control
the presence of various anions as well as the
crystallisation temperature.
Elecron microscopy has shown crystals of zeolite HS
"growing" from the surface of the zeolite A. Without
wishing to be bound by theory it is suggested that this
surface modification effect results in the desired higher
oil adsorption values of the zeolite powder.
Crystalline zeolites (other than zeolite HS) are also
essential features of the present invention. Certain
crystalline zeolites are of great importance in most
currently marketed heavy duty granular detergent
compositions on account of their detergent builder
capacities. Aluminos_ilicate builders include those having
the empirical formula:
Mz ( zA102 ) y ) ~ x H20
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WO 96/34079 PCTIUS96/04224
8
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.
Useful aluminosilicate 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 Patent 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 aluminosilicate ion
exchange material has the formula .
Nal2 [ (A102 ) 12 ( S i02 ) 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
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WO 96/34079 PCT/US96/04224
9
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,
a
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
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/min.ute/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 (0.26g
Ca++/litre/minute/gram/litre).
The granular agglomerates of the present invention also
comprise other detergent ingredients.
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WO 96/34079 PC'TIUS96/04Z24
Water-soluble salts of the higher fatty acids, i.e.,
"soaps", are useful anionic surfactants in the compositions
herein. This includes alkali metal soaps such as the
sodium, potassium, ammonium, and alkylammonium salts of
higher fatty acids containing from about 8 to about 24
carbon atoms, and preferably from about 12 to about 18
carbon atoms. Soaps can be made by direct saponification
of fats and oils or by the neutralization of free fatty
acids. Particularly useful are the sodium and potassium
salts of the mixtures of fatty acids derived from coconut
oil and tallow, i.e., sodium or potassium tallow and
coconut soap.
Useful anionic surfactants also include the water-soluble
salts, preferably the alkali metal, ammonium and
alkylolammonium salts, of organic sulfuric reaction
products having in their molecular structure an alkyl group
containing from about 10 to about 20 carbon atoms and a
sulfonic acid or sulfuric acid ester group. (Included in
the term "alkyl" is the alkyl portion of acyl groups.)
Examples of this group of synthetic surfactants are the
sodium and potassium alkyl sulfates, especially those
obtained by sulfating the higher alcohols (Cg-Clg carbon
atoms) such as those produced by reducing the glycerides of
tallow or coconut oil; and the sodium and potassium alkyl
benzene sulfonates in which the alkyl group contains from
about 9 to about 15 carbon atoms, in straight or branched
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WO 96/34079 PC'T/US96/04224
11
chain corifigurat:ion, e.g., those of the type described in
U.S. Pat. Nos. 2,220,099 and 2,477,383; and methyl ester
~ sulphonates. Especially valuable are linear straight chain
alkyl benzene sulfonates in which the average number of
carbon atoms in the alkyl group is from about 11 to 13,
abbreviated as C11-C13
Other anionic surfactants herein are the sodium alkyl
glyceryl ether sulfonates, especially those ethers of
higher alcohols derived from tallow and coconut oil; sodium
coconut oil fatty acid monoglyceride sulfonates and
sulfates; sodium or potassium salts of alkyl phenol
ethylene oxide ether sulfates containing from about 1 to
about 10 units of ethylene oxide per molecule and wherein
the alkyl groups contain from about 8 to about 12 carbon
atoms; and sodium or potassium salts of alkyl ethylene
oxide ether sulfates containing from about 1 to about 10
units of ethylene oxide per molecule and wherein the alkyl
group contains from about 10 to about 20 carbon atoms.
Other useful anionic surfactants herein include the water-
soluble salts of esters of alpha-sulfonated fatty acids
containing from about 6 to 20 carbon atoms in the fatty
acid group and from about 1 to 10 carbon atoms in the ester
group; water-soluble salts of 2-acyloxy-alkane-1-sulfonic
acids containing from about 2 to 9 carbon atoms in the acyl
group and from about 9 to about 23 carbon atoms in the
alkane moiety; alkyl ether sulfates containing from about
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WO 96/34079 PCT/US96/04224
12
to 20 carbon atoms in the alkyl group and from about 1
to 30 moles of ethylene oxide; watersoluble salts of olefin
sulfonates containing from about 12 to 24 carbon atoms; and '
beta-alkyloxy alkane sulfonates containing from about 1 to
3 carbon atoms in the alkyl group and from about 8 to about
carbon atoms in the alkane moiety. Although the acid
salts are typically discussed and used, the acid
neutralization can be performed as part of the fine
dispersion mixing step.
Water-soluble nonionic surfactants are also useful as
surfactants in the compositions of the invention. Indeed,
preferred processes use anionic/nonionic blends. Such
nonionic materials 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.
Suitable nonionic surfactants include 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.
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13
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 from 1 to 25 moles of ethylene oxide
per mole of alcohol, especially 2 to 7 moles of ethylene
oxide per mole of alcohol. Particularly preferred are the
condensation products of alcohols~,having an alkyl group
containing from about 9 to 15 carbon atoms; and
condensation products of propylene glycol with ethylene
oxide.
Other preferred nonionics are polyhydroxy fatty acid amides
which may be prepared by reacting a fatty acid ester and an
N-alkyl polyhydroxy amine.~The preferred amine for use in
the present invention is N-(R1)-CH2(CH20H)4-CH2-OH and the
preferred ester is a C12-C2o fatty acid methyl ester. Most
preferred is the reaction product of N-methyl glucamine
(which may be derived from glucose) with C12-C2o fatty acid
methyl, ester.
Methods of manufacturing polyhydroxy fatty acid amides have
been described in WO 9206073, published on 16th April,
1992. This 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-C2o methyl ester. It also
says that the formulator of granular detergent compositions
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14
may find it convenient to run the amidation reaction in the
presence of solvents which comprise alkoxylated, especially
ethoxylated (EO 3-8) C12-C14 alcohols (page 15, lines 22-
2~). This directly yields nonionic surfactant systems which
are suitable for use in the present invention, such as
those comprising N-methyl glucamide and C1~-C14 alcohols
with an average of 3 ethoxylate groups per molecule.
Semi-polar nonionic surfactants include water-soluble amine
oxides containing one alkyl moiety of from about 10 to 18
carbon atoms and 2 moieties selected from the group
consisting of alkyl groups and hydroxyalkyl groups
containing from 1 to about 3 carbon atoms: water-soluble
phosphine oxides containing one alkyl moiety of about 10 to
18 carbon atoms and 2 moieties selected from the group
consisting of alkyl groups and hydroxyalkyl groups
containing from about 1 to 3 carbon atoms; and water-
soluble sulfoxides containing one alkyl moiety of from
about 10 to 18 carbon atoms and a moiety selected from the
group consisting of alkyl and hydroxyalkyl moieties of from
about 1 to 3 carbon atoms.
Ampholytic surfactants include derivatives of aliphatic or
aliphatic derivatives of heterocyclic secondary and
tertiary amines in which the aliphatic moiety can be either
straight or branched chain and wherein one of the aliphatic
substituents contains from about 8 to 18 carbon atoms and
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at least one aliphatic substituent contains an anionic
water-solubilizing group.
Zwitterionic surfactants include derivatives of aliphatic
quaternary ammonium phosphonium, and sulfonium compounds in
which one of the aliphatic substituents contains from about
8 to 18 carbon atoms.
Useful cationic surfactants include water-soluble
quaternary ammonium compounds of the form RqR5R6R~N+X-,
wherein R4 is alkyl having from 10 to 20, preferably from
12-18 carbon atoms, and R5, R6 and R~ are each C1 to C~
alkyl preferably methyl: X- is an anion, e.g. chloride.
Examples of such trimethyl ammonium compounds include C12-Ci4
alkyl trimethyl ammonium chloride and cocalkyl trimethyl
ammonium methosulfate.
The granular detergents of the present invention can
contain neutral or alkaline salts which have a pH in
solution of seven or greater, and can be either organic or
inorqanic in nature. The builder salt assists in providing
the desired density and bulk to the detergent granules
herein. While some of the salts are inert. many of them
also function as detergency builder materials in the
laundering solution.
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Examples of neutral water-soluble salts include the alkali
metal, ammonium or substituted ammonium chlorides,
fluorides and sulfates. The alkali metal, and especially
sodium, salts of the above are preferred. Sodium sulfate
is typically used in detergent granules and is a
particularly preferred salt. Citric acid and, in general,
any other organic or inorganic acid may be incorporated
into the granular detergents of the present invention as
long as it is chemically compatible with the rest of the
agglomerate composition.
Other useful water-soluble salts include the compounds
commonly known as detergent builder materials. Builders
are generally selected from the various water-soluble,
alkali metal, ammonium or substituted ammonium phosphates,
polyphosphates, phosphonates, polyphosphonates, carbonates,
silicates, borates, and polyhyroxysulfonates. Preferred
are the alkali metal, especially sodium, salts of the
above.
Specific examples of inorganic phosphate builders are
sodium and potassium tripolyphosphate, pyrophosphate,
polymeric metaphosphate having a degree of polymerization
of from about 6 to 21, and orthophosphate. Examples of
polyphosphonate builders are the sodium and potassium salts
of ethylene diphosphonic acid, the sodium and potassium -
salts of ethane 1-hydroxy-1,1-diphosphonic acid and the
sodium and potassium salts of ethane, 1,1,2-triphosphonic
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acid. Other phosphorus builder compounds are disclosed in
U.S. Pat. Nos. 3, 159, 581; 3, 213, 030; 3, 422, 021; 3, 422, 137;
3, 400, 176 and 3, 400, 148.
Examples of nonphosphorus, inorganic builders are sodium
and potassium carbonate, bicarbonate, sesquicarbonate,
tetraborate decahydrate, and silicate having a molar ratio
of Si02 to alkali metal oxide of from about 0.5 to about
4.0, preferably from about 1.0 to about 2.4. The
compositions made by the process of the present invention
does not require excess carbonate for processing, and
preferably does not contain over 2% finely divided calcium
carbonate as disclosed in U.S. Pat. No. 4,196,093, Clarke
et al., issued Apr.l, 1980, and is preferably free of the
latter.
Polymers
Also useful are various organic polymers, some of which
also may function as builders to improve detergency.
Included among such polymers may be mentioned 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
CA 02216813 2001-04-18
18
as those of malefic and acrylic acids. Molecular weights for
such polymers vary widely but most are within the range of
2,000 to 100,000. Other suitable polymers are polyamine
N-oxide polymers, copolymers of N-vinylpyrrolidone and
N-vinylimidazole, polyvinylpyrrolidone polymers,
polyvinyloxazolidones and polyvinylimidazoles or mixtures
thereof.
The organic polymers may be used in an amount of about at
least 30o by weight.
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 malefic acid, itaconic acid,
mesaconic acid, fumaric acid, aconitic acid, citraconic acid
and methylenemalonic acid.
Silicone Oils
Particulate suds suppressors may also be incorporated either
directly in the agglomerates herein by way of the powder
stream into the agglomerating unit, or in the finished
composition by dry adding. Preferably the suds suppressing
activity of these particles is based on fatty acids or
silicones. The silicone oil may be used in the detergent
composition or component in an amount of at least about 30o by
weight.
In one embodiment of the present invention the silicone oil is
adsorbed onto the specified Zeolite A.
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Optionals
Other ingredients commonly used in detergent compositions
can be included in the compositions of the present
invention. These include flow aids, color speckles,
bleaching agents and bleach activators, suds boosters or
suds suppressors, antitarnish and anticorrosion agents,
soil suspending agents, soil release agents, dyes, fillers,
optical brighteners, germicides, pH adjusting agents,
nonbuilder alkal_Lnity sources, hydrotropes, enzymes,
enzyme-stabilizing agents, chelating agents and perfumes.
These optional ingredients, especially optical brighteners,
may be incorporated either directly in the agglomerates
herein or may be components of separate particles suitable
for dry adding to the agglomerates of the present
invention.
Processing
Useful agglomeration processes are defined in EP-A-510746,
published on 28th. October 1992, and in W093/25378,
' published on 23rd December 1993. These applications
describe the agglomeration of solids with a high active
neutralised surfactant paste. However it will be
CA 02216813 2001-04-18
appreciated that the high active neutralised paste could be
replaced fully or in part by other surfactants, especially
nonionic surfactants (as in EP643130, published on 15th
March 1995), or by organic polymers or silicone oils.
Preferred embodiments of the process are described in more
detail in the Examples below.
TEST METHOD
Oil absorption values can be determined by following
British Standards, HS3483 . Part 7 :1982 (corresponding to
ISO 78?/5-1980). A 5 gram sample of zeolite having a free
alkalinity of less than 0.5% should be used. Oil absorption
value (OAV) is expressed as .
OAV = Volume of oil (ml)
Wt. of Zeolite sample (g)
EXAMPLES
All values are expressed in % by weight. Zeolite levels are
expressed on a hydrated basis (including 15% by weight of
bound water)
Ex. 1 Ex. 2 Ex. 3 Comp.
Ex. A
Zeolite A/HS * 32 22 52 -
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21
Zeolite A # _ _ - 32
C12-15 AS 24 31 - 24
C12-15 AE3S 6 8 _ 6
Sodium 25 12 13 25
Carbonate
Co-polymer - _ -
12
Nonionic Surfactant - - 30 -
Water 5 5., - 5
Misc. 8 10 5 g
Zeolite A/HSt has an oil absorption capacity of 45.5
ml/100g supplied by Industrial Zeolites (UK) Ltd. of
Thurrock, Essex, England.
Zeolite A # has an oil absorption capacity of 36 ml/100g
supplied by Degussa under the Trade Mark Wessalith~.
C12-15AS is sodium alkyl sulphate, the alkyl chains
principally comprising C12 to C15.
C12-15AE3S is sodium alkyl ether sulphate, the alkyl chains
principally comprising C12 to C15, and with an average of 3
ethoxy groups per molecule.
Co-polymer is a co-polymer of acrylic and malefic acid.
Nonionic surfactant.comprises 7 parts of ethoxylated
alcohol, the alkyl chains principally comprising C12 to
C15, and with an average of 3 ethoxy groups per molecule;
and 3 parts of C12-14 polyhydroxy fatty acid amide.
Misc is mainly sulphate with some other minor impurities.
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Granular agglomerates having the composition of Example 1
were prepared by the following process. The powdered raw
materials (Zeolite A/HS and sodium carbonate) were added to
the pan of an Eirich~ mixer rotated at 64 rpm and mixed for
seconds. The mixer pan was then stopped and preheated
surfactant paste (50°C), 80~ surfactant active in aqueous
solution, was then added in slices into a hollow formed in
the middle of the powder. Loose powder being scooped over
the paste to completely cover it. The mixer was then
started again with pan rotating at 64 rpm, and choppers set
at 2500 rpm. The mixing was stopped when granular
agglomerates started to form (at this point the current
drawn by the Eirich rose from 2.8 to 3 amps.
The resulting granular agglomerates were free-flowing and
had less than 25~ by weight of oversized particles
(oversized particles be considered as those having particle
size of greater than 1600 micrometers).
Granular agglomerates having the composition of Examples 2
were prepared by the following process.
A paste comprising the surfactants was prepared by
sulphating and neutralising appropriate alcohols. The
resulting paste had a water content of 18~.
The paste was pumped into a high shear mixer (Loedige CB~).
Simultaneously Zeolite A/HS and sodium carbonate were fed '
into the high shear mixer and intimately mixed with the
high viscosity paste therein. The resulting mixture was
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transferred directly to a low shear mixer (Loedige IQ~I~)
were agglomerates formed. After exiting from the low shear
mixer the agglomerates were screened to remove oversize
"lumps" and fines. Finally the agglomerates were cooled in
a fluid bed and stored prior to dry mixing with other
detergent powders in order to form a finished product.
The residence time in the high shear mixer was
approximately 8 seconds, and the residence time in the low
shear mixer was approximately 35 seconds.
Granular agglomerates having the composition of Example 3
were prepared by the same process as Example 2, the anionic
surfactant paste being replaced by the nonionic surfactant
maintained as a viscous paste at 70°C.
a
Granular agglomerates having the composition of Comparative
Example A were prepared by the same process as Example 1,
using the same time of mixing the powders and paste as that
used in Example 1. The resulting granular agglomerates had
greater than 25$ by weight of oversized particles
(oversized particles be considered as those having particle
size of greater than 1600 micrometers).
