Note: Descriptions are shown in the official language in which they were submitted.
CA 02030306 1998-07-21
DETERGENT COMPOSITION
FIELD AND BACKGROUND OF THE INVENTION
This invention relates to the particulate
detergent compositions cont~;n;ng relatively high levels of
detergent active and furthermore where the detergent
comprises a high level of anionic detergent, at least 30% by
weight of the composition. Such compositions may in
particular be suitable for cleaning fabrics, although they
may be intended for other uses. This invention also relates
to the production of such compositions.
Detergent compositions containing lower levels of
anionic detergent active are commonplace, and are often
prepared by spray drying as is well known. At first sight it
might be supposed that there would be no difficulty in
making compositions with higher concentrations of anionic
detergent because many anionic detergent active materials
can be prepared in more or less solid form consisting of
substantially pure anionic detergent, or at least containing
a very high percentage of anionic detergent.
However, such materials tend to be sticky and to
cake together whereas products which are suitable for retail
sale are required not to be sticky and to be free flowing. A
sticky solid with a tendency to cake is of course
inconvenient during manufacture as well as at the time of
use.
2 ~o~a306
In fact it is difficult to produce a particulate
solid which both contains a high proportlon of detergent
active and also has satisfactory properties for use as part
or the whole of a product suitable for retail sale.
SUMMARY OF THE PRIOR ART
US 4515707 (Brooks) discloses a procedure in
which anionic detergent acid is neutralized and mixed with a
powdered ingredient to produce a powder which is described
as dry. This is used subsequently as a raw material for the
production of detergent bars. The powdered ingredients
which are referred to can be made with varying absorbencies
and the document does not disclose materials of unusual
absorbency.
US 4213874 (Williams et al) discloses the
production of aluminosilicates which have an oil absorbtion
of at least 75ml/lOOgram. It is disclosed that they may be
used to absorb nonionic detergents in detergent products.
US 4707290, GB 1485371 and GB 1591518 disclose the use of
absorbent solids to act as carriers for nonionic detergents.
Nonionic detergents are a different problem to anionic
detergents in that the nonionic materials are generally
liquids (which need to be made into solid form) whereby
anionic detergen~ts are generally 5~ C i~ th~i- own right.
2~ It is known to apply powdered materials to the
surface of a particulate solid to reduce sti~kin~cs and
en~nce its abilities to flow as a powder. This however is
merely a surface treatment.
3 s~ 3 0 6
THE INVENTION
We have now found that the flow properties and
caking resistance of detergent powders containing a high
level of anionic detergent can be improved by incorporating
a particulate filler with a relatively high oil absorption
value.
Accordingly, in a first aspect, the invention
provides a particulate detergent composition, the particles
of which contain at least 55% by weight of anionic
detergent active which is any of linear and branched alkyl
benzene sulphonates, alkane sulphonates, secondary alcohol
sulphates, primary alcohol sulphates, alpha olefin
sulphonates, alkyl ether sulphates, fatty acyl ester
sulphonates, and mixtures of these, and also contain a
particular filler with an oil absorption value of at least
lOOml/lOOg, this filler being distributed within the
particles of the composition in intimate mixture with said
detergent active, and the weight ratio of the filler to the
anionic detergent active lying in the range from l:lO to
l:l.
In a further aspect, this invention provides a
particulate detergent composition, the particles of which
contain at least 30% by weight of anionic detergent active
and also contain a particulate filler with an oil
absorption value of at least 200ml/lOOg, this filler being
distributed within the particles of the composition in
intimate mixture with the detergent active, the amount of
the particulate filler being such that the weight ratio of
B
3 ~
3A
the filler to anionic detergent active lies in the range
from 1:10 to 1:1, more preferably 1:8 to 2:3.
This ratio range signifies that the amount of
filler is not greater than the amount of anionic detergent
active.
It is preferred that the filler has a mean
particle size not greater than 20 micrometres.
In a still further aspect the invention provides
a process of preparing a particulate detergent composition
which process comprises incorporating a particulate filler
into a fluid or semi-solid composition containing anionic
detergent active which is any of linear and branched alkyl
benzene sulphonates, alkane sulphonates, secondary alcohol
sulphates, primary alcohol sulphates, alpha olefin
sulphonates, alkyl ether sulphates, fatty acyl ester
sulphonates, and mixtures of these so that the filler is
intimately mixed with the anionic detergent active, said
particulate filler having an oil absorption value in excess
of lOOml/lOOgrams, and forming the resultant mixture into a
particulate composition with the filler distributed within
the particles of the composition, the amounts of anionic
detergent active and filler being such that the composition
contains at least 55 wt% of anionic detergent active
ranging from 1:10 to 1:1.
A still further aspect of the invention provides
a process of preparing a particulate detergent composition
which process comprises incorporating a particulate filler
into a fluid or semi-solid composition containing anionic
B
3 ~ ~
3B
detergent active, so that the filler is intimately mixed
with the anionic detergent active, said particulate filler
having an oil absorption value in excess of 200ml/lOOgrams,
and forming the resultant mixture into a particulate
composition with the filler distributed within the
particles of the composition, the amounts of anionic
detergent active and filler being such that the composition
contains at least 30 wt~ of anionic detergent active and
has a weight ratio of filler to anionic detergent active
r~n~in~ ~ro~ 1:10 to 1~1
",/
~B
~ Q ~ ~ 3 ~ ~
DETAILED DESC~IPTION
Test for oil absorbency
As stated above, the present invention contains
particulate filler with an oil absorption value which is
equal to, or eX~,e~C, a minimum value.
The oil absorption value of the filler is to be
determined by the following test which is in accordance with
British Standard 3483 : Part B7 : 1982. The test for oil
absorption is performed by placing a weighed sample of the
test powder on a plate and then adding linseed oil from a
burette. The oil is added a few drops at a time. After
each addition the powder is mixed vigorously with the oil
using a palette knife. Addition of oil is continued until a
paste of smooth consistency is formed. The paste should
just spread without cracking or crumbling. The oil
absorption value is expressed as the volume (ml) of oil
absorbed per lOO gram of powder.
Applicability of compositions
~t ~ C~r~ n
~D
~a3~3~6
- , 5
may be marketed directly as a washing product.
Alternatively it can be mixed with other particulate
material to form a finished product. In particular, a
particulate detergent composition according to the invention
may be mixed with a second particulate composition which
contains other constituents of a final detergent
composition, such ~as detergency builders. There are various
possibilities for such a second composition. It might
contain no detergent active or very little. It might
contain a substantial quantity of detergent active but
nevertheless a lower proportion than in a composition
according to this invention which is mixed with it.
A~ixi~g the composition in accordance with the invention
would then serve to increase the overall proportion of
detergent active. There could even be a commercial
advantage in circumstances where ~mi xi ng a composition in
accordance with this invention did not increase the overall
proportion of detergent active - for instance by achieving
beneficial physical properties or by e~Ancing overall
production from available process plant.
Production routes
Production of compositions in accordance with this
invention may be ~C~l i ch~ by cuu~ on~l routss for the
manufacture of part~culate detergent ro~positions with a
high level of detergent active, provided there is a stage
when the detergent active is in a fluid or semi-solid form.
The particulate filler is mixed with the detergent actlve at
20~3~
this stage and leads to an improvement in the properties of
the particulate composition which is produced. In some
inst~ es a particulate state would not be achieved without
the filler.
If the overall process entails neutralization, the
filler can be mixed with the acid form of the detergent
active before neutralization. The filler may even be used
as a base to neutralise the acid form of the detergent
active, i.e. part of the material used as filler may serve
to effect neutralisation. Another possibility is to
neutralise the active and mix the filler with the resulting
neutralised paste before this becomes solid.
A fluid or semi-solid mixture contA~ g the
detergent active and the filler may be dried to solidify it,
for example by means of a drum dryer. A viscous dough may
be produced with a formulation such that the dough can be
extruded but will then solidify into a hard solid which can
be comminuted to desired particle size.
One preferred method of producing compositions of
this invention is by neutralizing an acid form of an anionic
detergent active with an alkali metal oxide, hydroxide or
carbonate (which may be a true carbonate, bicarbonate or
sesquicarbonate) to produce a viscous dough, mixing the
particulate filler with this dough, allowing the dough to
2~ harden to a solid and comminuting the solid. Neutralization
may be effected in the presence of little or no added water.
Alternatively there may be some ~ herate addition of
water: this can lead to a solid which is already in
'- 2C3~3~
equilibrium with atmospheric humidity. Generally, the
amount of water added (if any) is not more than 10%, more~
preferably not more than 5%, by weight based on the total
weight of acid detergent and carbonate.
Such neutralization and admixing of filler can be
carried out in various types of high shear mixer. One
possibility is a Z-blade mixer, another possibility is a
cavity transfer mixer whose use as a chemical reactor is
disclosed in our European patent application 194812, yet
another possibility is a twin screw extruder. Other
intensive mixers which may be used consist of vessels which
contain rotating blades for mixing and high speed knives for
dispersing, manufactured for example by Lodige (Trade Mark)
ex Morton ~Ach~P Co Ltd, Scotland.
If production is by a route which entails
neutralization of the acid form of an anionic detergent
active, other detergent active may also be mixed in. For
example some preneutralised detergent active or nonionic
detergent active may be mixed in.
When the powder has been made it may be given a
surface coating of a flow-improving aid which may itself be
a particulate solid having the oil absorption property
required for the filler used in this invention. Use of such
materials as a surface coating is convent~o~ he
2~ eY~mplPC below demonstrate t~at it does not, by itself,
achieve the results achieved by the invention.
Materials : Detergent Active
2~Q3~
As mentioned above compositions according to this
invention must contain at least 30% by weight of active
detergent. Preferably they contain more, e.g. at least 40%
or even at least 55~. The amount of detergent active
present may range as high as 90% by weight of the
composition.
Various~detergent actives may be utilised,
selected from the conventional categories of anionic,
nonionic, cationic and amphoteric. Preferably anionic
detergent active predominates; even if detergent active from
another category is present the anionic detergent active may
itself provide 30%, 40% or even 55% or more of the
composition.
Specific examples of anionic detergent actives
useful in this invention are: linear and branched alkyl
benzene sulphonates, alkane sulphonates, secondary alcohol
sulphates, primary alcohol sulphates, alpha olefin
sulphonates, alkyl ether sulphates, fatty acyl ester
sulphonates, and mixtures of these. The invention is
particularly applicable when at least part of the detergent
active is alkyl benzene sulphonate, or a mixture thereof
with fatty acyl ester sulphonate or primary alcohol
sulphate.
Materials : Particulate Filler
As stated above the filler should have an oil
absorbency, measured according to the test stated, of at
least lOOml/lOOg. PrefOE ably it is higher such as at least
%~3Q~
150ml/lOOg, better at least 200ml/lOOg and most preferably
at least 300ml/lOOg.
The filler may be water soluble but is more
likely to be water insoluble.
Preferably the mean particle size of the filler
is not over 20 micrometres, better not over 10 micrometres.
A small particle size is especially desirable for an
insoluble filler, since it facilitates rinsing the filler
away after a detergent composition has been used. Small
particle size increases the speed of dissolution of a
soluble filler. An alternative way to state desirable
particle slze is that the particle size distribution
includes substantially no particles larger than 50
micrometres. These particles however will generally be
aggregates of smaller particles, typically having a size in
the range from 5 to 200 nanometres and prP~om~n~tly (or
even wholly) in the narrower range lO nanometres to 100
nanometres. Such smaller partlcles can be disting~1sh~ by
electron microscopy.
A variety of materials are available with suitable
particle size and oil absorbency. Suitable inorganic
materials tend to be finely divided solids obt~i~e~ by
precipitation. Materials can be produced in such form
include c~l~c~ alumin~c~ tes~ calcium silicates,
magnesium s~l~c~tes and calcium ~ L~. O~her materials
which can be suitable, sub;ect to testing their oil
absorbency, are diatomaceous earths and finely divided
cellulosic fillers.
2~30~6
The amount of filler included in the composition
will generally range from 3~ to 50% by weight, usually 5% to
40%.
Other materials may be included in addition to the
detergent active and specified filler, for example
detergency builder, alkaline salts or other filler of lesser
oil absorbency. A small quantity of moisture will almost
always be present.
EXAMPLES
Examples I-V and Comparative Examples A-C
A number of compositions and comparative
compositions were prepared using a st~n~ard procedure as
follows.
T.i ne~r alkyl benzene sulphonic acid with an
average Cl 3 alkyl chain length was charged to a Z-blade
mixer. Temperature was maint~i~e~ at 80~C. Sodium
carbonate was added over ten minutes with continuous mixing
during which time carbon dioxide was evolved. A particulate
filler was then added over a period of 15 minutes and
r~ xi n~ continued for 5 minutes.
The dough produced by this procedure was removed
from the mixer and cut into pellets. These were allowed to
cool to ambient tem~e~aL~, har~Pni n~ as they did so. The
pellets were milled into a powder. This was mixed with 2%
by weight of a conventional flow aid which coated the
surfaces of the powder particles.
The mean partirle s~e, bulk density and dynamic
11 ~e3~3û6
flow rate of the resulting powders were tested. Their
content of sodium alkyl h~7~ne sulphonate was checked
analytically and found to be approximately 60% by weight,
except in Example 5 where the content was approximately 52%
by weight. The dynamic flow rate, in ml/s, was measured
using a cylindrical glass tube having an internal diameter
of 35mm and a len~th of 600mm. The tube was securely
clamped with its longit~ axis vertical. Its lower end
was terminated by means of a smooth cone of polyvinyl
chloride having an internal angle of 15~ and a lower outlet
orifice of diameter 22.5mm. A beam sensor was positloned
150mm above the outlet, and a second beam sensor was
positioned 250mm above the first Qe~Cor.
To determine the dynamic flow rate of a powder
sample, the outlet orifice was temporarily closed, for
example, by covering with a piece of card, and powder was
poured into the top of the cylinder until the powder level
was about lOOmm above the upper s~sor. The outlet was then
opened and the time t (secon~s) taken for the powder level
to fall from the upper sensor to the lower sensor was
measured electronically. The result is the tube volume
between the se~ors, divided by the time measured.
C~k~g resistance of the particles and their
hardness after e~os~e to air was tested ~y the following
2~ pr~r~ re The powder was spread in a thin layer in a dish
and ~XpO~ to atmosphere at 37~C and 70% relative humidity.
After exposure for one week the powder was graded for feel.
Also a sample of the powder which had been e~ose~ was
12 ~ 3~6
compressed under a stAn~Ard load in a 2cm diameter
cylindrical die to form a pellet. The hardness of the
material in this pellet was tested with a cone penetrometer.
The cone had an angle of 9~ 10' and was applied under 100
gram load for 10 seconds.
The compositions of these examples and comparative
examples are set QUt in Tables 1 and 2 below. In the case
of comparative example A an increased quantity of sodium
carbonate was used rather than a separate particulate
filler. In other words a part of the sodium carbonate,
having an oil absorption value of 63ml/lOOg, constituted the
particulate filler. In this comparative example the sodium
carbonate was added over a period of lS minutes in view of
the greater quantity used.
lS The various solids were no~i nA 1 ly dry, which in
practice means that they contained a small percentage of
absorbed moisture.
CA 02030306 1998-07-21
13
TABLE 1
Components Charged in the Z-blade Mixer (Kg)
II III IV V A B C
5 Alkyl benzene
sulphonic
acid (1) 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0
Sodium
carbonate (2) 0.2 0.2 0.2 0.4 1.0 0.8 0.2 0.2
Water 0.020.020.02 0.02 0.02 0.020.02 0.02
*Socal U3 (3) 0.6
*Alusil ET (4) - 0.6
*Microsil GP (5) - - 0.6 0.4 0.12
*Kaolin (6) - _ 0.6
*Durcal 40 (7) - - - - - - - 0.6
(1) Sulphonated Dobane 113, ex Shell
(2) Light Soda Ash, ex ICI
30 (3) Calcium Carbonate, ex Solvay
(4) Aluminosilicate, ex J Crosfield and Sons
(5) Silica, ex J Crosfield and Sons
(6) Speswhite grade, ex English China Clays
(7) Calcium Carbonate, ex Sturge.
*denotes trade mark
14 ~ Q~
TABLE 2
Properties of Materials Produced
_ II III IV V A B C_
Mean particle
size (~m) 515505 465 485 510 500 515 525
Bulk density
(Kg/m3) 668652 654 664 700 676 668 650
Dynamic flow
rate (ml/sec) 75 80 96 96 90 75 75 70
Penetration of
compacted pellet
after
exposure (mm) 146.8 2.4 3.5 4.2 19 20 22
Feel of the
powder after
exposure* S MS MC MC MC VS VS VS
Oil absorption
value of the
filler
(ml/lOOg) 120200 330 330 330 63** 51 25
* S = Soft, MS = Moderately Soft, MC = Moderately Crisp,
VS = Very Soft
** Oil absorption value of the light soda ash.
It can be seen that below an oil absorption value
of lOOml/lOOg the y~o~euLies of the yO.d~l are not much
affected by the oil absorption value of the filler whereas
considerable i,.~ylovements are observed at higher oil
absorption values.
In each case the col~en~o~l flow aid used to
2~3~30~
provide a surface coating on the particles was Alusil ET.
The inferior results with the comparative examples
demonstrate that a conventional dusting or surface coating
with a flow aid does not itself achieve the benefit of this
invention.
Examples 6 and 7, ~Comparative Examples D and E
These Examples commence using pastes, i.e.
previously neutralised detergent active. The procedure was
as follows.
Sodium primary alcohol sulphate paste or sodium
alkyl h~n7~ne sulphonate paste was charged to a Z-blade
mixer. Temperature was maint~ne~ at 80~C. Sodium
carbonate was added over five minutes with continuous
~;~;ng. A particulate filler was then added over a period
of 15 minutes and mixing continued for 5 minutes.
The dough produced by this procedure was removed
from the mixer and cut into pellets. These were dried and
allowed to cool to ambient temperature, hardening as they
did so. Excepting pellets from Example E, which could not
be milled as they were too soft, the pellets were milled
into a powder. This was mixed with 2% by weight of a
conventional flow aid (Alusil ET).
The physic~l properties were detP~m~ned as for
2~ Examples 1-5. The active contents were measured
analytically and are shown in Table 4.
16 2~3~31~
TABLE 3
Components charged in the Z-blade mlxer
VI D VII E
5 Sodium primary alcohol
sulphate paste (1) 1.0 1.0 - -
Sodlum alkyl benzene
sulphonate paste (~2) - - 1.0 1.0
Sodium carbonate (3) 0.25 0.4 0.45 0.6
Microsil GP (4) 0.15 - 0.15
(1) Derived from coconut oil, active content 62%.
(2) Derived from noh~e 113, ex Shell, active content 75%.
(3) Light Soda Ash, ex ICI.
(4) Silica, ex J Crosfield and Sons.
17 ~ 3~
TABLE 4
Properties of Materials Produced
VI D VII E
Moisture content after
drying (%) 15.3 14.1 3.1 2.1
% Active 52 52 54 54
Mean particle size (um) 400 355 630 - (1)
Bulk Density (Kg/m3) 560 585 680
Dynamic flow rate
(ml/sec) 80 75 90
Penetration of
comr~cted pellet after
exposure (mm) 0.8 2.3 5.5
Feel of the powder
after exposure (3) C MS(2) MC
Oil absorption value of
the filler (ml/lOOg) 330 63 330 63
(1) Could not be satisfactorily comminuted.
(2) Formed some lumps.
(3) C = Crisp, MC = Moderately Crisp, MS = Moderately Soft.
Once again it was apparent that incorporation of
filler with high oil absorption value led to powders with
enhanced physical properties. Examples 7 and E are an
instance where a part~ te solid was not achleved without
the fil~P~,
