Note: Descriptions are shown in the official language in which they were submitted.
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W 096/04359 ~ . q ~
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G~ANULATION IN A FLUIDISED ~E~
he present invention relates to a detergent composition
having a low bulk density ~BD) and a process for its
production by dry neutralisation and further envisages the
use of a fluidised bed for manufacture of such detergent
compositions.
It is known in the art to obtain detergent powders by the
step of spray drying. However, such a process of spray
drying is attended with the disadvantage that it is both
capital and energy intensive and, consequently the product
obtained therefrom is expensive. Simultaneously, a
distinct advantage accruin~ from such a procéss is that the
powders have a low bulk density of 350 to 600 g/L.
Henkel 4304062 describes the production of a ~ n;ng
active surfactant ~n~nnlAte in which an anionic surfactant
in acid form is neutralized with an aqueous alkali solution
under high gas pressure in a granulation and drying
chamber. In this process the drying of a non-surfactant
liquid co~ponent by using hot air is an essential step.
The process of dry n~ntrAli2ation for preparing detergent
powders is known in the art but this often results in
powders having a high bulk density. Indian patent no.
166307, (Hindustan Lever Ltd~ refers to specific use of an
internal recirculating fluidised bed and ~-n~;~nC that use
of a conventional fluidised bed will lead a lumpy and
sticky process.
East German Patent No. 140 987~VEB Waschmittelwerk)
discloses a continuous process for the production of
granular washing and cleaning compositions, wherein liquid
components such as nonionic surfactants or the acid
precursors of anionic surfactants are sprayed onto a
u--li~UO 1~ ~1 -- ~ ~ I J ~ JU ~
~004~1 2 ~ 953 ~ 3
powdered builC-r mat-rlal, ~ y oodium
trlpol~b _'-te tSTPP) havin~ a hish ph~s- Ir content to
obt~ln a ~roduct with bulk don~tity ranglng ~rom 530 - sao
~ Nowev-r, th- groces8 acccrding to tho 8aid E8st
G~rm~n Patcnt la r--trict-d to the use o~ STPP having a
hlgh ghA~a II content
G~tl404317 ~clo~-- th- ~r~paration o~ a detorgQnt powder
of low or rttod-rate bulk d-n~lty by a dr~ neutralization
proCe~ 9ulphonic acid i~ mix-d wlth an oxce~ o~ ~oda
ash $n thc p~ ~ o~ ~u~ricient water tc initlat~ the
noutralization re~ction tut not enough to w-t the resulted
product which i~ ln the ~orm o~ a ~ree-~lowin~ Dowder ~he
proce-~ 18 carriat o~t in a mlxing a~aratue, ~or examplo a
ribbon blender, planot~ry mixer or air tran8iQr ~lxor In
a lttixin~ rattt~, th~ particulatQ detorgent r-t~ri~l is
8ub~ect~d to co~sro~ive rorce~ which may l-ad to an
lncrea-e i~ bulk don~ity
We have now round that the di-advanta~e8 o~ th ~rior art
~aybe obviated by nc:~rAll~n~ an acid precursor o~ a
~ur~ctant in d rluidl~-d b~d to produco a powder havins a
low bulk den~ity
The inv neioh provide~ in a firAt ~pect, a ~roc-s~t ior tho
~rod~tio~ or a ~articulaCe det-rgent co~po~ition h8ving a
b~lk d~n~ity in the r~nSe 35C to ~50 g/l w~ich co~prlsos
ioe~lng a Darticul~te mcteri~l com~ri~ing a n4utralisln~
a~ent and
AMENDE~ SH~ET
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W096/04359 P~~ c
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optionally a detergency builder in a fluidisation zone,
fln;~;c;ng the material, contacting a liquid precursor of
an anionic surfactant with the fluidised material to effect
at least partial, and preferably substantially complete,
neutralisation of the acid precursor and to e~fect the
formation of deter~ent particles comprising the neutralised
precursor acid.
Preferably the fluidisation zone is provided by means of a
fluid bed.
According to a further aspect of the invention, there is
provided a process for the production of a particulate
detergent composition having a low bulk density which
comprises:-
. introducing a particulate material comprising a
builder and a neutralizing agent into a fluidised bed;
ii. introducing linear alkyl benzene sulphonate (LAS) acid
into the said bed over a sufficient time to effect at
least partial neutralization of the acid and to attain
the required properties of the powder.
The invention also provides a detergent composition
obtainable by a process as defined in the claims.
The process may be carried out in either batch or
c~nt;nn~Us mode of operation as desired. The term
~detergent composition~ as used herein includes a detergent
material which may be mixed with other conventional
materials for example bleaches and enzymes to produce a
fully formulated product and also a detergent , ~nt,
often referred to as an adjunct, which may be treated
further to produce a detergent material which may then be
mixed with other materials as desired.
W096/04359 2 1 9 5 3 l 3 ~
In accordance with this invention the process envisages dry
ne1ltr~lization of the acid precursor of an anionic
surfactant with a neutralising agent by fluidisation of the
neutralising asent; preferably the process is carried out
in a fluidised bed. The process of dry neutralisation
refers to at least partial and preferably subst~nti~lly
complete neutralisation of the acid precursor while the
mixture remains in particulate form. Suitably, addition of
the acid precursor is controlled so that it does not
accumulate in the unneutralised form in the detergent
composition.
The neutralising agent is suitably particulate and
comprises an ~lk~l;n~ inorganic material, preferably an
nlk~l;n~ salt. Suitable materials include alkali metal
carbonates and b~cAr~nn~tes for ex3~lo sodium oaltc
thereof.
The neutralising agent is suitably present at a level
sufficient to neutralise fully the acid precursor. If
desired a stoichiometric excess of neutralising agent may
be employed to ensure complete neutralisation or to provide
an alternative function, for example building, in the case
of sodium r~rhnn~t~.
In addition to the anionic surfactant obtained by the
neutralisation step further anionic surfactants or
nonionic, cationic, zwitterionic, amphoteric or semipolar
surfactants and mixtures thereof may be added at a suitable
time. Suitable surf~ot~ntS include those ~enerally
described in "Surface active agents and detgents " Vol I by
Schwartz and Perry. Thus if desired soap derived from
saturated or unsaturated fatty acids having Cl2 to C~5
carbon atoms may also be present as an anionic surfactant.
'Cli ~ t~'.\ \ll L.\.C'ill~:\ ot.; ~ J tiU ~:3u~
Lc--~ lW~i 14: ~ 2 1 9 5 3 1 3
~200~J1 '
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~he dat~r~ont actlv~ ultably ~ -nt at a level o~ 5 to
40%, pre~erably 12 to 30% by wei~bt o~ the dotorgent
co~o5ition
Th- detoroent ccm~o~ition ~uitably contain~ a Cetergoncy
bullder ~he builder may be lntroduc~d with the
n~ ~r~l~8;n~ ag-nt and~or ~dd-d cub~ecu-ntly a~ deolred
Prefcr~bly, the builder ~a introducod with thc -~ut~Al~sing
4~ent
Any co ~- ~gn~l build~r may b- e~Dloyed; ~ultable bullders
includ- ~odlum carbonat-, zeollte, ~odium tripcl~h~h~tc
~9TP~ ~odlum cltrat- and~or bigh nuriace Area c~lcite
The bullder can ~l~o oon~i~t o~ on- o~ the ~bove singularly
or in combin~tlon wlth cther b~ld~
The builder and ncutrali~ing ~g~nt may be the same
matorlaL, ~or ox~mDl~ ~odiwm c~ n-se, ln wh~ch caae
~uf~ici-nt t~tAl wlll be omployed ~or both ~un~r
~h- bu~ld-r io Duit_bly gr-~ent at a l-vel o~ 15 to 65S and
~re~er~bly 15 to 50S by w-i~ht oS eh- detcr~ent
co;npcJitlon,
D~tergent powder ebtA~n~d by the pre~ent invention ha~ -
low bulk den8~ty in the ran~e 350 to 650 g/l, or ~50 to
650~ or e~ple, ln th- ~roxlmlty Or 500 g/L and i8
tnu~ com~r_bl~ to a bulX d~n~lty obr~1- by the ~ethod o~
~pray dryin~
Ogtlonally and ~re~erably ~ ~low aid i~ lncorgorated lnto
the comryositlon ~he flow ~ld may be ~ixed with the
neutral~lng agent and, if pre8ent, builder prlor to or
~ha~ L to gartlal or ccmglete additicn o~ the 3cld
y~ s~r ~t 1~ ecl~lly gref-rred that the flow aid be
~dd-d prlor to or aftor partlal introduction of the acld
AMEN~ED SHEET
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W096l04359 r~ IA79
precursor as a significant reduction in the bulk density of
the final powder may be achieved.
The flow aid is suitably present in an amount of 0.1 to 15%
by weight of the detergent composition and more preferably
in an amount of 0.5 to 5~.
Suitable flow aids include crystaline or amorPhous alkali : :
metal silicate, calcite, diatomaceous earth, silica, for
example precipitated silica, magnesium sulphate, and
calcium carbonate, for example precipitated calcium
carbonate. ~ixtures of these materials may be employed as
desired. In the preferred embodiment, the flow aid is
Dicamol.
The composition may also comprise a particulate filler
which suitably comprises an inorganic salt, for example
sodium sulphate and sodium chloride. The filler may be
present at a level of 5 to 50~ by weight of the
composition.
The detergent composition produced according to the
invention suitably comprises the detergent active and
builder and optionally one or more of a flow aid, a filler
and other minor ingredients such as colour, perfum,
fluorescers, bleaches, enzymes.
We have further found that a significant reduction in bulk
density may be secured by selecting raw materials-having
certain particle size characteristics.
Suitably the particulate material(s) have a particle size
distribution such that not more than 5% by weight of the
particles have a particle size greater than 250~. It is
also preferred that at least 30% by weight of the particles
have a particle size below 75~. Suitably the particulate
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~ W096/04359 r~
material(s) has an average particle size below 200u to
provide detergent powders having a particularly desired low
bulk density.
If desired a controlled amount of water may be added to
facilitate neutralisation. The water may be added in
amounts of 0.5 to 2% by weight of the final detergents
composition. Any such water is suitably prior to or
together or alternating with the addition of the acid
precursor.
Suitably the particulate material is introduced into a
fluidised bed and the required amount of LAS acid is then
introduced preferably by spraying onto the said material
and preferably from the top. If present the flow aid maybe
introduced with the starting material. However, it is
preferred that the flow aid be added after part
introduction of part of the LAS acid to obtain a lower bulk
density.
The fluid bed is suitably operated at a temperature of
ambient to 60~C. The air flow is sufficient to cause
fluidisation and is preferably in the range 0.6 to 1 ms~l.
Fluidisation of the solid material is an essential feature
of the present invention as this facilitates neutralisation
and granulation whilst keeping the particles apart. This
is to be contrasted with mixing processes in which the
particles, are intentionally contacted and compressed,
which may lead to higher bulk density powder and poorer
powder pro~erties.
The invention is illustrated by the following non-limiting
examples.
Ex~MPL~ 1 to 19
A powdered builder~inorganic ~lk~1 ine material (in Examples
1 to 4, sodium carbonate performed both functions) and a
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W096l04359 PCT~P95/02935
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filler was introduced into a ~lui~i bed and was fluidised by
operating at a superficial air velocity above the minimum
fluidisation::velocity. The temperature in the fluid bed
was from ambient to 60~C. Linear alkyl benzene sulphonic
acid (LAS acid) was sprayed onto the powdered mix in the
fluid bed.
The relative amounts of the various rn~pnn~nts of the
composition were varied and are listed below in Table l.
Examples 1 to 3 illustrate the effect of lncorporation a
flow aid (in this case Dicamol) to the composition at
different polnts in the process. In Example 1 the flow aid
was not added to the material. In Example 2, the flow aid
was added to the starting material prior to the
introduction of LAS acid. In Example 3, the flow aid was
added after lntroduction of 50% of the LAS acid. Exam~le 4
illustrates the benefits obtained in employing a fine grade
of particulate material. The results are shown below in
Table 1.
T~3LE 1
EXAMPLE EXAMPLE EXAMPLE EXAMPLE
1 2 3 4
LAS 17 17 17
So~ ~qh 30 30 30 30
Dicamol - 2* 2** 2**
Salt 45 43 43
Fine salt - - - 43
BD (g,~L) 687 625 603 546
DFR 85.72 36.77 88.23 93.8
(ml~sec)
OD (%) 81.6 80.6 82.3 82.5
~Rate of Dissolution
*Dicamol added initially
**Dicamol added after 50~ LAS
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W096/04359 I~
g
The rate of dissolution of the powder was determined by
adding powder to 11 of water to provide a concentration of
1.4%, mixing at 100 rpm and measuring the ~nnfl~ ivity of :-
the solution until a constant reading was reached. The
figures quoted refer to the level of powder dissolved after
about 90 seconds.
Examples 2 and 3 illustrate that a significant reduction in
bulk density may be achieved by ~flfl;tinn of the flow aid
either prior to or subsequent to introduction of part of
the LAS acid.
Further powders, Examples 5 to 19, as detailed below in
Tables 3 to 5 were prepared according to the process
described for Examples 1 to 4 and various raw materials
having a different particle size distribution were
employed. Table 2 summarises the size distribution of the
various materials.
TABLE 2
Pro~erties of various raw materials
Size Soda ash ¦Na2SO~ ¦Salt ¦Fine ¦STPP
distribution l l ¦Salt
(micron) %wt
>500 1.8 0.12 1.78 1.00 0.94
500 - 250 2.06 0.60 80.40 1.26 1.40
250 - 150 6.52 21.90 14.80 10.02 6.86
150 - 100 26.20 55.14 2.88 21.80 24.88
100 - 75 16.20 8.56 0.14 24.07 7.92
<75 47.14 13.68 - 36.83 58.00
Mean particle 92.7 138.2 360.30 112.5 85.7
size ~u~
BD, g/L 508 1,347 1,070 997 649
DFR, ml/sec No flow 83.33 142.85 No flow No flow
W096/04359 2 l 9 5 3 1 3 r~ rA7~c
Table 3
Examples ~: 5 6 7 8 9 10
LAS ~ 17.0 20.0 23.0 23.7 25.0 27.1
Moisture, % 6.8 6.0 4.8 6.0 4.5 5.1
STPP, % 35.0 22.0 35.0 35.0 25.0 25.0
Soda ash, ~ 22.0 20.0 22.0 22.0 20.0 20.0
Fine salt, ~ - 30.0 - - 16.0 15.0
Alk.silicate, ~ - l.0
Bulk density, g/L 500 510 500 490 500 495
DFR, ml/sec 100 120 120 120 100 88
TABLE 4
Examples 11 12 13 14 15
LAS Acid, % 28.5 28.7 29.13 29.6 31.1
Moisture, % 4.5 6.7 6.2 7.4 6.8
STPP, % 25.0 35.0 25.0 35.0 35.0
Soda ash, % 20.0 22.0 20.0 22.0 22.0
Fine salt, % 16.0
Na2SO4, % - - 16.0 - -
Bulk density, g/L 514 470 510 500 520
DFR, ml/sec 120 100 88 102 115
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Table 5
Example 16 17 18 19
LAS, ~ 17.0 17.0 17.0 13.0
Soap, % - - - 4.0
Soda ash, % 22.0 30.0 35.0 20.0
STPP, ~ 35.0 - - 35.0
~SA calcite, % - - 16.0
Moisture, % 6.8 3.5 3.0 4.0
sD, g/L 500 530 480 500
DFR, ml/8eC 100 100 120 150
Tables 3 and 4 show the results for STPP built powders
~nnrAining active in the range of 17 to 31%. m e soda ash
and STPP had a similar particle size distribution as shown
in Table 2 and formulations based on such builder systems
resulted in products with bulk density close to 500 g/L.
Table 5 shows powders based on various builder systems,
i.e. STPP, soda ash and HSA calcite. soth the soda ash and
STPP built f, lAtions resulted in powders with BD of
about 500 ~/l whereas f~ tionS based on HSA calcites
resulted in powders with bulk density lower than 500 q/L.
Example 19 relates to a mixed active system cnntAininS 13%
LAS AD and 4% soap and resulted in powder with bulk density
of 500 g/L.
