Note: Descriptions are shown in the official language in which they were submitted.
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Wo9~129216 r~ .,,5, s?gg
2187517
DETERGENT POWDER COMPOSITIONS COMPRISING METAL ION-CHELANT
COMPLEX AND ANIONIC FUNCTIONAL POLYMER.
The present invention relates to detergent powders which
essentially comprise a complexed chelating agent and an
anionic polymer. The powders may be readily prepared by
spray drying.
.
Detergent components and compositions have been made Uslng
various spray drying techniques fo~r many years. Typically
various detergent active materials are dissolved or
dispersed in an aqueous solution which is then pumped under
high pressure to an atomiser, such as a nozzle or a
spinning disc.
.
WO95/2921~ E~~ 3'!0~799
21 ~7 51 7
Excess water is then removed from the atomised droplets by
a drying gas, usually hot air. The dried droplets then form
a free-flowing granular product. Most granular products
prepared in this way comprise both organic and inorganic
materials. One prior art disclosure of a detergent
component in which the principle detergent active material
is a complexed chelating agent is:
US 4 259 200, issued on March 31st, 1981 discloses
complexes of chelating agent with metal ions. The complexes
are said to have improved chemical stability in bleaching
compositions. Various methods of obtaining a particulate
product which comprises the metal/chelating agent complexes
are also disclose~d, including spray-drying, by including
inorganic salts such as tetraborate, triphosphate,
sulphate .
In fact, chelating agents are frequently precomplexed with
magnesium in order to protect them from degradation in the
presence of bleach. However molar ratios of magnesium:
chelating agent of greater than 3:1 are difficult to
prepare due to precipitation from a~ueous solution.
Precipitation in a spray drying process rapidly leads to
blockage of the nozzle. Furthermore, powders which
essentially consist of chelating agent / magnesium complex
have a very low r te of solubillty.
Wo 95/29216 2 ! 8 7 5 1 7 r~l,u~ o1799
3
It has now been found that the addition of various polymers
which comprise anionic func~ional groups avoids the
precipitation problem, allows higher molar ratios of
chelating agent to magnesium to be prepared by spray
drying, and greatly increases the rate of solubility of t~e
resulting powder.
The addition of anionic polymer also enables powders to be
prepared which have a very high organic content, preferably
greater than 80%. Such powders which are difficult to
prepare by other means, provide a convenient method for
handling and processing organic polymers.
Summary of the Invention
The present invention relates to free-flowing detergent
powder which is prepared by spray drying, the powder
comprising:
(a) from 10% to 90~ by weight of a complex, said
complex comprising
(a) (i) a chelating agent and
~a) (ii) a metal ion selected from the group
consisting of magnesium, calcium,
strontium, zinc and aluminium, and
mixtures thereof,
characterised in that the powder further comprises
~ b) from 10% to 90% by weight of a polymer, said
WO 95/29216 2 ~ ~ 7 5 ~ 7 P~ 1799
4 :
polymer comprising functional groups which
are anionic.
Preferably the powder comprises less than 20~, more
preferably less than 10~ by weight (on anhydrous basis), of
inorganic components other than the metal ion (a) (ii).
Most preferably the total level of aluminosilicate and
carbonate (on anhydrous basis) is less than 10~ by weight.
The chelating agen'c is preferably selected from the group
consisting of phosphonic acid, succinic acid, the salts of
phosphonic or succinic acid, or mixtures thereof, even more
preferred chelating agents are diethylene triamine penta
(methylene phosphonic acid), or ethylenediamine-N-N'-
disuccinic acid, or their salts, or mixtures thereof.
The preferred metal ion is magnesium.
The molar ratio of the metal ion to the chelating agent is
preferably greater than 3 :1.
The polymer may comprise carboxylate functional groups,
especially the water-soluble salts of homo-and copolymers
of aliphatic carboxylic acids such as acrylic acid, maleic
acid, vinylic acid, itaconic acid, mesaconic acid, fumaric
acid, aconitic acid, citraconic acid, methylenemalonic acid
and mixtures thereof.
WO 95/29216 2 1 8 7 5 1 7 ~ '0 ~799
S
A preferred polymer lS a copolymer of maleic and acrylic
acid having a molecular weight of from 2000 to lO0 000.
optionally the free-flowing detergent powder may also
comprise a cationic surfactant. Where present the cationic
surfactant may be present at from 1% to 80% by weight,
from 2% to 20% by weight of dimethyl ethoxy ammonium
chloride being preferred.
Detailed Description of the Invention
The essential components of the present invention are a
chelating agent and a polymer comprising anionic functional
groups. Examples of these will now be given in more detail.
Chelating Agents
The chelating agents suitable for use in the present
invention can be chosen from a wide range of chemicals
which are known to the man skilled in the art. Examples of
suitable chelating agents are phosphonic and succinic acids
and their salts.
c
The polyphosphonates are the sodium and potassium salts of
ethylene diphosphonic acid, the sodium and potassium salts
WO 95129216 2 t 8 7 5 1 7 1 ~ 'C 1799
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of ethane l-hydroxy-1, l-diphosphonic acid and the sodium
and potassium salts of ethane, 1,1, 2-triphosphonic acid.
Examples of particularly suitable chelating agents are
ethylene diamine tetra (methylene phosphonic acid) and
diethylene triamine penta ImethYlene phosphonic acid).
Another preferred chelating agent is ethylenediamine-N, N' -
disuccinic acid ~EDDS) or the alkali metal, alkaline earth
metal, ammonium, or substituted ammonium salts thereof, or
mixtures thereof. Preferred EDDS compounds are the free
acid form and the sodium or magnesium salt thereof.
Examples of such preferred sodium salts of EDDS include
NaEDDS, Na2EDDS and Na4EDDS. Examples of such preferred
magnesium salts of EDDS include Mg EDDS and Mg2EDDS. The
magnesium salts are the most preferred for inclusion ir~
compositions in accordance with the invention.
The structure of the acid form of EDDS is as follows:
H-N-CH2-CH2 -N-H
CH2 CH CH CH2
COOH COOH COOH COOH
EDDS can be synthesised, for example, from readily
available, inexpensive starting ~material such as ~aleic
anhydride and ethylene diamine as follo~s: :
Wo gS/29216 2 1 8 7 5 1 7 r~ c 1799
~ . 7
o
/\
2 O=C C=O + NH2-CH2-CH2-NH2 - NaOH EDDS
CH = CH
A more complete disclosure Df methods for synthesising
EDDS from commercially available starting materials can be
found in US Patent 3,158, 635, Xezerian and Ramsay, issued
November 24, 196~.
The synthesis of EDDS from maleic anhydride and ethylene
diamine yields a mixture of three optical isomers,
[R,R], [S,S], and [S,R], due to the two asymmetric carbon
atoms. The biodegradation of EDDS is optical
isomerspecific, with the [s,SI isomer degrading most
rapidly and extensively, and for this reason the [S,S]
isomer is most preferred fQr inclusion in the compositions
of the irlvention.
The [S, S] isomer of EDDS can be syntheslsed from L-
aspartic acid and 1,.2-dibromoethane, as follows:
2 CH2--CH-NH2 + Br-CH2-CH2-BR NaOH ~ [S,S]EDDS
COOH COOH
WO 95/29216 2 1 ~ 7 5 1 7 P~,IIL ~ C ~799
A more complete disclosure of the reaction of L-asparti-c
acid with 1,2-dibromoethane to form the [S,S] isomer o~
EDDS can be found in Neal and Rose, Stereospeciflc Ligands
and Their Complexes of Ethylenediaminediscuccinic Acid,
Inorganic Chemistry, Vol 7 (1968), pp. 2405-2412.
Specific examples of carboxylates and other chelanting
agents which are suitable for use in the present invention
are given below.
HO COOH
H02C y
)~ /~COOH
HO2C NH
- Iminodiacetic acid - N- 2 -Hydroxypropyl sulphonic
acid
OH ~COOH
Ho3S~,N~COOH
- Aspartic acid, Ncarboxymethyl N-2 Hydroxypropyl 3
sulphonic acid.
COOH
OH ~
Ho3S ~ N~ COOH
COOH
WO 95/29216 2 1 8 7 5 1 7 r~ o l7ss
- ~Alanine N, N Diacetic acid
N ~
COOH--
- Aspartic acid -N, N Diacetic acid
H02C~
~N COOH
H02C
COOH
- Aspartic acid N-Monoacetic acid
N~,C02H
r~
-Iminodisuccinic acid
NH~C02H
n' C02H
H02C C02H
- Amino acid based chelanting agents such as
C02H
~NH~COOH
Co2H
WO 95/29216 2 1 8 7 5 1 7 r ~ ,o ~799
Iso serine di acetic acid ( ISDA)
IC02H
H 02C ~--OH
N
H 02C
2-Phosphonobutane-1,2-4-tricarboxylic acid
C02H
~1203P to2H
C02H
GADS
rrNH
H~2C C02H C02H
Also useful as chelanting agents are:
Alkyl iminodiacetic acid; dipicolinic acid; hydroxy-1, 1-
ethyl l den~ diphosphoni c aci d ( '~1~ DP ) and d~r i vati ves .
O95129216 2 1 8 7 5 ~ 7 E~lrl~ c~79g
..
Polymers and/or Co-polymers
The polymers and co-polymers of the present invention may
be chosen from a wide range of 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, polyacrylates,
polyaspartates 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 lO0, 000
Polymeric polycarboxyate 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.
Most preferred for use in the present invention are
copolymers of maleic and acrylic acid having a molecular
weight of from 2000 to lO0000, carboxymethyl cellulose and
mixtures thereof.
WO 95129216 r~ o ~799
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optional ingredients in ~he spray dried powder of the ~
present invention are cationic surfactants. Usef~l cationic
surfactants include water-soluble quaternary ammonium
compounds of the form R4RsR6R7N+X~, wherein R4 is alkyl
having from 10 to 20, preferably from 12-lB carbon atoms,
and Rs is Cl to C2D, R6 and R7 are each Cl to C7 alkyl
preferably methyl; X~ is an anion, e.g. chloride. Examples
of such trimethyl ammonium compounds include C12_14 alkyl
trimethyl ammonium chloride, C12_1~ alkyl dimethyl ethoxy
ammonium chloride and C12_14 alkyl trimethyl ammonium
methosulfate. ~:
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Wo 95/29216 2 1 8 7 5 1 7 PCT~IS95104799
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Processing
An essential step of the process of making the spray-dried
powder of the present invention is the preparation of the
complex of the chelating agent with the metal ion.
Preferably this is done by dissolving a salt of the metal
ion into a solution of the chelating agent in the required
ratios. The molar ratio of metal ion to chelatirlg agent is
preferably at least l:l, the present invention allows molar
ratios of greater than 3: l to be prepared, most preferred
is a molar ratio of about 5: l . Whilst any metal salt may be
used, magnesium sulphate is most preferred.
The anionic polymer is added to the solution comprising the
complex together with any other optiollal ingredients. The
resulting slurry or solution is then spray dried by
conventional means.
The most preferred method for spray drying is the use of
spinning disc atomiser.
Iqanufacture of finished detergent compositions
- In the most simple embodiment of the present invention, the
free-flowing spray-dried powder is admixed with other
detergent powders to ~orm a finished granular detergent
product. It is an important advantage of the present
WO9S/29216 2 1 875 1 7 ~ '01799
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invention that the spray-dried powder dissolves rapidly in
water to release the chelating agent and polymer as early
as possible into the washing process. Components of the
finished detergent composition may be chosen from a very
wide range of detergent active materials. Common examples
include surfactants, builders, bleach, bleach activator,
enzymes, optical brighteners, soil release polymers, dye
transfer inhibiting agents, softening cray, perfume, etc.
Alternatively the spray-dried powder of the present
invention may be further processed, for example by
additional granulation, agglomeration, compaction steps. A
particuIarly preferred process is described in EP 508543,
published on 14th October, 1992. In this application a
process is disclosed for structuring or "conditioning" a
high active surfactant paste and then granulating in the
presence of detergent powder. It is foreseen that the
spray-dried powder may be a component either of the
conditioning step, or of the granulation step, or of both
steps. Using this process in combination with the spray-
dried powder of the present invention enables free-flowing
detergent granulates to be produced having a surfactant
content of at least 40% by weight, and a bulk density of at
least 600~g/l.- --- - - ~ ~~ ~~~~ ~ ~- ~ - --~~
wog5/29216 ~ ~ ~ 7 ~ 3 ~ P~rl~ S C~799
EXAMPLES
(all ~ are by weight)
Example l
The following free-flowing powder composition was
prepared:
Acrylic / Maleic copolymer (MW = 50000) 72 %
Diethylenetriaminepenta 10 %
(methylene phosphonic acid)
MgSO4 l O %
Water 8 %
100 g
The composition was prepared by mixing a 40% active
solution of the sodium salt of the copolymer, a 25~ active
solution of the phosphonic acid and the sulphate powder
(MgSO4 . 7 H20) to give a slurry.
The slurry was then processed through a continuous spray
dryer with co-current air inlet and a rotating disc (15000
rpm) at the top of the tower. After the exit from the
bottom of the tower, two fluid beds in series provide
further drying and cooling of the spray dried product.
Wo 9~/29216 ~ ~ 8 7 5 1 7 ~ c c ,,99
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After classi~ication ~removal of fines and overslze
particles) by vibrating screens, the resulting spray dried
powder had a bulk density of 450 g/l (measured by the
repour cup method).
Example 2 ~
The following free-flowing powder composition was prepared
by the same prQcess as in example l, except that
diethylenetriaminepenta (methylene phosphonic acid~ was
replaced by ethylenediamine - N, N - ~ii Cllr~;n; c acid used
as a 33% active solution:
Acrylic / Maleic copolymer (MW = 5000a) 43.5 %
Ethylenediamine - N, N - Disuccinic Acid 15 . 5 %
MgSO4 31 . 0 %
Water l O . 0 %
100 ~
The resulting powder is free flowing and has a bulk density
of 460 g/l.
WO95/29216 21~7517 r~ s. 1~99
. 17
Example 3 - -
The following free-flowing powder composition was prepared
by the same process as in example l
Acrylic / Maleic copolymer ~MW = 50000) 42.0 %
Ethylenediamine - N, N - Disuccinic Acid 24 . 5 %
MgSO4 2 4 . 5 %
Water - 9 %
100 %
The resulting powder is free flowing and has a bulk density
of 450 g/L.
Example 4
The following free-flowing powder composition was prepared
by the same process as in example 1
Acrylic / Maleic copolymer (MW = 50000) 62 . 0 %
Ethylenediamine - N, N - Disuccinic Acid 14 . 0 ~
MgSO4 14 . 0 %
Water 10.0 %
100 %
WO 95/29~16 . 2 1 8 7 5 1 7 ~ ' C ,799
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The resulting powder i~; free flowing and has a bulk density
of 430g/L.
