Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
1~37384
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FABRIC WASHING PROCESS A~D DE~ERGE~
CO~POSI~IOW ~OR USE ~HEREI~
he p~esent invention relates to fabric washing
processes and to the compositions which are adapted for
this purpose, using synthetic detergent active compounds
together with phosphate detergency builders. ~ne
invention concerns in particular fabric washing using
detergent compositions which contain levels of the
phosphate detergenc~ builders which can be lower than
conventional phosphate builder levels, whilst still
achieving good detergency results.
It is known to include tripolyphosphates as builders
in detergent compositions. In U~ 4 113 644 (Ashcraft)
there is described a detergent composition containing
both orthophosphate and tripolyphosphate in addition to
high levels of alkalimetal pyrophosphate,
.. ~
~137384
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~ detergent dishwashing composition is known from
GB 1 224 777 (Armour) which is intended for use at
substantially neutral pH and which contains in addition
to an acid orthophosphate, encapsulated sodium tripoly-
phosphate with the obaect of providing good cleaningaction over an extended period of time~
It is also known to wash fabrics in two steps.
~hus GB 996 193 (Henkel) describes adding a first
concent~ate to water to form a wash liquor and subsequently
adding a second concentrate to the same liquor. By
suitable choice of components in these concentrates,
enhanced bleaching of fabrics can be obtained.
~he present in~ention on the other hand is concerned
with low phosphorus containing compositions having
enhanced building properties.
According to a first aspect of the invention there
is provided a process for washing fabrics comprising the
steps of:
( i) contacting the fabrics with a wash liquor containing
a synbhetic detergent active compound and an alkali-
metal or ammonium orthophosphate; and
(ii) subsequently contacting the fabrics with a wash
liquor containing a synthetic detergent active
compound and an alkalimetal or ammonium tripoly-
phosphate, each of said wash liquors having a pX
between about 8 and about 12 and each of said wash
liquors containing substantially no alkalimetal
pyro~hosphate .
~he process can be conducted if desired in two
stages, or example using a prewash as step (i) and
then a main wash as step (ii), the fabrics being
substantially separated from the prewash liquor before
being contacted with the main wash liquor. In this
event there is often some carry-over of the ingredients
in the pre-wash into the main wash, so that there is some
1137384
_ 3 _ C.1057
benefit from the presence of residual alkalimetal ortho-
phosphate in the main wash liquor. Many modern domestic
washing machines are designed for sequential pre- and main
washes, or the consumer may himself arrange the sequential
washing.
Alternatively, the washing process can be conducted
in a single stage, where the liquor used in step (i)
remains in contact with the fabrics during step (ii).
~his can be achieved by including the tri-
polyphosphate together with the orthophosphateand synthetic detergent compound in a single composition,
but treating the former to delay its dissolution so that
in step (i) it remains in an undissolved form, or by
adding the tripolyphosphate to the wash solution later
than the other ingredients. ~his can again be achieved
manually or automatically. Dissolution of the tripoly-
phosphate is desirably delayed for at least 15 seconds,
preferably at least one and especially at least 5 to 30
minutes, or even more after dissolution of the bulk of
the orthophosphate, to encourage maximum precipitation
of calcium orthophosphate before addition of the former.
According to a second aspect of the invention there
is provi~ed a detergent composition for carrying out such
a method, comprising a synthetic detergent active compound,an
lakalimetal or ammonium orthophosphate andan alkalimetal or
ammonium tripol~phosphate characterised by means for
delaying the solubility of said alkalimetal or ammonium
tripolyphosphate when the composition is added to water
to form a wash liquor, said composition yielding a pH
o between about 9 and about 11 when dissolved in 12H(Ca)
water at ~0C and at a concentration of 0.1% w/v, and
said composition containing subs'antially no alkalimetal
pyrophosphate.
~he detergent composition may be in the form of two
containers, the first container containing at least a
part of said synthetic detergent active compound and
1137384
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the orthophosphate and the second container
containing the alkallmetal or ammonium tripolyphosphate
and optionally a further part of the synthetic detergent
active compound. In use, the contents of the first
container are released into water to form a wash liquor
for step (i) of the process and subsequently the contents
of the second container are released to form a wash
liquor for step (ii) of the process.
~he delayed addition of the tripolyphosphate to the
washing solution is advantageous in giving decreased
deposition of inorganic phosphates on the washed fabric,
compared with the simultaneous addition of the tripoly-
~phosphate and orthophosphate. It is believed that this
is due to the substantially complete precipitation of
calcium orthophosphate by reaction with hard water before
dissolution of the tripolyphosphate. lhis, in turn,
appears to lead to decreased hydrolysis of the tripoly-
phosphate, compared with the amount of hydrolysis which
takes place when the water had not been pre-softened in
this way; one o~ the products of hydrolysis is alkali
metal or ammorium pyrophosphate which apparently causes
high levels of inorg~n;c deposition on the washed fabric,
and hence the control of the rate of hydrolysis of the
tripolyphosphate as proposed leads to decreased fabric
deposits~
~ he washing process of the invention can be
accomplished manually, if desired, but is normally
accomplished in a domestic or commercial laundry washing
machine. he latter permits the use of higher wash
3 temperatures and alkalinity, and more effective agitation,
all of which contribute generally to better detergency.
High wash temperatures (at least about 60C) and high
alkalinity (over about pH 10) also particularly assist the
precipitation of the calcium orthophosphate to achieve more
effective water softening. However, any ~ash temperature
between a bient end boiling mey be employed with any normal
~137384
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degree of alkalinity (pH 8-12). ~he type of washing
machine used, if any, is not significant.
It is preferred to accomplish the washing process
in the joint presence of both the orthophosphate and the
tripolyphosphate, but with the dissolution of the latter
being delayed, as described above. This has the advantage
of combining the water-softening action of both phosphates.
~his means, referring to the process of the invention, that
the first aqueous solu~ion is used to prepare the second
aqueous solution. An added advantage is that the detergent
active compound used in both solutions can then be the same
;substance or mixture of substances.
It should be appreciated that when in aqueous solution
in h æd water, the alkali metal or ammonium ortho-
phosphate and tripolyphosphate will be present whollyor partially in the form of the calcium or magnesium salts,
which are insoluble for the orthophosphates and soluble
chelates in the case of the tripolyphosphate. But for
convenience the phosphates will be referred to generally
as bein~ in th~ ~1kali metal or ammonium salt form as
appropria~e, as if the aqueous solutions were prepared
with de-ionised water.
~ he detergent compositions used in the process of the
invention may be either solid or liquid compositions.
Either ph~sical form can be used if the orthophosphate and
tripolyphosphate are included in different compositions
for separate addition to the wash liquor. Compositions in
liquid form are suitable in particular for commercial
laundry use, in which buIk supplies of aqueous orthophos-
phate and tripolyphosphate solutions are available andare automatically dosed to the washing machines at the
appropriate times in the wash cycle. But if the orthophos-
phate and tripolyphosphate are included in a single
composition, with the latter being treated to delay its
solubility, the composition will normally be in solid form,
e.g. as a powdered or granulated product.
1137384
- 6 - C.1057
~ he invention includes processes for the preparation
of such detergent compositions suitable for fabric washing
according to the invention, by forming a detergent base
powder containing a detergent active compound or compounds
and optionally the alkalimetal orthophosphate, and admixing
with the base powder any further orthophosphate and an
alkalimetal or ammonium tripolyphosphate,treated to delay its
dissolution in water.
Preferably the base powder is prepared by spray dryin~ in
the normal way using conventional equipment and process
conditions. However, other conventional techniques may be
used for preparing the base powder containing the detergent
active compound and usually the orthophosphate.
Other heat-sensitive ingredients may also be admixed with the
base powder together with or separately from the treated
alkali metal or Pmmonium tripolyphosphate,for example oxygen
bleach co~pounds such as sodium perborate.
~ he alkali metal tripolyphosphate used in the compositions
of the i~vent~on is preferably sodium tripolyphosphate, but
if desired thg ~otassium or ammonium salts can be used. For
convenience the term alkali metal tripolyphosphate is used
below to include the sodium, potassium and ammoniumsalts~
~he alkali metal tripolyphosphates are generally represented
as ha~in$ ula M20(MP3)3 or MsP301o where M is sodium~
potassium or ammonium.
If the tripolyphosphate is treated to delay its dissolution,
for inclusion in a single composition with the orthophsophate,
this ma~T be accomplished in the production of the tripolyphosphate
or subsequen' l~o .
Specifically, the tripolyphosphates may be made with a large
particle size or the tripolyphosphate may be coated or
encapsulated with a slowly soluble material such as wax,
nonionic detergent compounds,higher fatty acids or a protein
such as gelati~. ~he rate of solubility of the tripolyphosphate
~5 may also be decreased by using them in partial calcium,
zinc or other polyvalent salt form. ~wo or more of these
- ` 1137384
-- 7
treatrents may also be combined, so as to ~ive close con.rol
over the solubility of the tripolyphosphate under the recommended
washing conditions.
The rate of solubility of the polymer phosphate may also
be controlled by granulating the tripolyphosphate with sodium
silicate. Specifically, the granules may contain the tripoly-
phosphate and an alkalimetal silicate having a M20:SiO2 ratio
of from about 1:2 to about 1:3.75 wherein M is an alkalimetal,
the granule being dried to a moisture content of less than 7%
by weight. A particularly useful granule of this type can be
achieved by granulating 1 part of tripolyphosphate with 3 parts
of sodium silicate having an Na20:SiO2 ratio of 1:2. The tri-
polyphosphate-containing granule may also contain a portion of
the synthetic detergent-active compound.
US 4 040 988 (Benson) describes granules formed by
sequestering builders and alkalimetal silicates and may be
referred to in this connection.
The delayed solubility of the tripolyphosphate may also
be achieved by dosing the composition in a two-compartment
sachet, the sachet being so constituted that when added to
water the contents of the first compartment, namely the alkali-
metal orthophosphate and at least some of the synthetic detergent
active compound are released before the contents of the second
compartment, namely the alkalimetal or ammonium tripolyphosphate
and optionally a further part of the synthetic detergent active
compound.
A sachet may be made from a first outer sheet of poly-
ethylene film, a second outer sheet of acrylic bonded polyester/
viscose non-woven fabric and an inner sheet of thermally
bonded polypropylene non-woven fabric, these three sheets
~eing heat-sealed together at the edges to define a
sachet with two compartments. Before sealing the final
1137384
- 8 - C.1057
edge, the first compartment between the two layers of
- non-woven fabric may be filled with the orthophosphate
and at least some of the synthetic detergent active
compound. ~he second compartment may be filled with the
alkalimetal or ammonium tripolyphosphate and optionally
a further part of the synthetic detergent acive compound.
In use the contents of the second compartment are
released after those of the first compartment because
they must pass through the first compartment before
entering the wash liquor.
~ he solution of the tripolyphosphate may also be
delayed by coating or encapsulating the tripolyphosphate with
a water-dispersible water-insoluble material or with a water-
soluble material. Examples of such coating materials
include fatty acids, alkanolamindes of fatty acids, glycerol
esters of fatty acids, long chain hydrocarbon aliphatic
alcohols, para~fin waxes, mineral oil, gelatin, sugar, non-
ionic surface active agents, polycinylalcohol and sodium
carboxymeth~lcellulose as described in U~ 3 847 830 (Williams)
and G~ 1 242 247 (Unilever).
~he orthophosphate used is either potassium or
preferabl~r sodium orthophosphate, as the latter is cheaper
and more readil~ available. Ammonium orthophosphate may
also be used, particularly if the composition is not made by
spray drying. ~ormally the tri-alkali metal salts are used,
but orthophosphoric acid or the di- or mono-alkalimetal
salts, e.d. gisodium hydro~en orthophosphate or mono-
sodium dih~drogen orthophospha~e could be used if
1:~37384
_ 9 - C.1057
desired in the production of the compositions. In the
i~ latter event other more alkaline salts should also be
present to maintain a high pH in the end product, i.e.
; with full neutralisation to the trialkali metal orthophos-5 phate salts. ~he use of a mixture of the monosodium
dihydrogen and disodium hydrogen orthophosphates in the
ratio of 1:~ to 2:3, especially about 1:2, is particularly
ç advantageous, as such a mixture (known as kiln-feed) is made
in the production of sodium tripolyphosphate and is readily
10 available.
~he orthophosphate can be used in the form
of the anhydrous or hydrated salts, but in the former case
, it is preferred to promote hydration during processing,
e.g. by adding the anhydrous orthophosphate to a detergent
15 slurry and spray drying to form a base powder. ~he alkali
metal pol~mer phosphates do not form hydrated salts as such,
and are normally used in predominantly anhydrous form, but
they are hygroscopic and tend to absorb atmospheric moisture.
~he amounts of salts used are expressed in anhydrous form.
. .
1137384
_ ~0 _ C.1057
~ he total amounts of the essential
tripolyphosphate and orthophosphate, and any
other phosphates which may be present in the detergent
compositions, are chosen according to the overall detergency
builder level which is desired in the detergent compositions
or according to the maximum permitted phosphorus content.
~ormally, when both the orthophosphate and
tripolyphosphate are present in a single composition, the
total phosphate builder level, which is preferably derived
solel~ from the aLkali metal tripolyphosphate and
orthophosphate, is between about 5/0 and about 50%~
preferabl~ about 10% to about 30% by weight of the
composition, with an amount of about 2% to about 20% each
of the tripolyphosphate and orthophosphate.
Preferably the amounts of the tripolyphosphate
and orthophosphate are each from about 5%
to about 15%, especially about 5% to 10% by weight of the
produc-t. ~he total amount of tripolyphosphate
and ~ orthophosphate is preferably from about
20 10% to about 25~o~ especially about 15% to about 2~/o~
by weight of the composition.
It is generally preferred to have amounts of the
orthophosphate and the tripoly-
phosphate, within the ratio of from about 3:1 to about 1:3
especiall~ about 2:1 to about 1:2, parts by weight. Ihese
ratios of tripolyphosphate to orthophosphate are particulæly
suitable for detergent compositions used at relatively
high product concentrations, i.e. 0.3% to 0.8% by weight
as is common practice in Europe, especially in front-loading
automatic washing machines, and where moderate levels o~
phosphates are allowed in the products, i.e. equivalent
to 2% to 7,b P.
It is preferable that the only phosphate detergency
builders used in the process of the i~vention should be the
~5 tripolyphosphate and orthophosphate.
.... . ..
~137384
~ 1~ ~ C~1057
In particular, it is desirable to use no alkali metal, i.e.
sodium or potassium, pyrophosphates in the compositions as
this tends to increase inorganic deposition as mentioned
above.
Some pyrophosphate is generally found as impurities
at low levels in other commercial aIkali metal phosphates,
and some pyrophosphate may also be formed by hydrolysis
of any polymer phosphate during processing, for example
during slurry making. Hence, total absence of alkali metal
pyrophosphate is generally unattainable in the detergent
compositions. It is particularly preferred to have not more
than about 5% especially not more than about 2.5% of alkali
metal pyrophosphate present in the compositions, as at
higher levels the amounts of inorganic deposits on the
washing machine parts become significantly more noticeable.
~ ~~ However, some of the tripolyphosphate may be replaced
b~ an alkalimetal or ammonium polymerphosphate such as is
described in our copending application No
(GB 7937167 Case ~o C.1052).
! 20 The process of the invention is necessarily
accom~lished using synthetic anionic, nonionic, amphoteric
or zwitterionic detergent active compound or mixture
thereof. Detergent compositions normally
include f~om about 2.5% to about 50%, preferabl~ about
5% to about 3~, and especially about 1C% to about 25% by
weight of such iDb~redients. Many suitable detergent compounds
are commerciallr available and are fully described in the
litera-ture, for example in 'ISurface Active Agents and
Detergents", Volumes I and II, by Schwartz, Perry & ~erch.
~he preferred detergent compounds which can be used
are synthe~ic anionic and nonionic compounds. The former are
usually water-soluble alkali metal salts of organic sulphates
and sulphonates having aIkyl radicals containing from about
8 to about 22 carbon atoms, the term aIkyl being used to
include the aI~yl portion o~ higher acyl radicals. Examples
of suitable synthetic anionic detergent compounds are sodium
`- 1137384
_ ~ _ C.1057
and potassium alkyl sulphates, expecially those obtained by
sulphating higher (C8-C18) alcohols produced for example
from tallow or coconut oil; sodium and potassium aIkyl
(Cg-C20) benzene sulphonates, particularly sodium linear
secondary alkyl (C10-C15) benzene sulphonates; sodium alkyl
glyceryl ether sulphates, especially those ethers of the
higher alcohols derived from tallow or coconut oil and
synthetic alcohols derived from petroleum; sodium coconut
oil fatty monoglyceride sulphates and sulphonates,; sodium
and potassium salts of sulphuric acid esters of higher
(C8-C18) fatty alcohol-alkylene oxide, particularly
ethylene oxide, reaction products; the reaction products
of fatty acids such as coconut fatty acids esterified with
isethionic acid and neutralised with sodium hydroxide;
sodium and potassium salts of fatty acid amides of methyl
taurine; aIkane monosulphonates such as those derived by
reacting alpha-olefins (C8-C20) with sodium bisulphite and
those der;ved from reacting paraffins with S02 and Cl2 and
then hydrolysing with a base to product a ra~dom
sulphonate; and olefin sulphonates, with term is used to
describe the material made b~ re.acting olefins, particularly
C10-C20 alpha-olefins, with S03 and then neutralising and
hydrol~sin~ the reaction product. ~he preferred anionic
detergent ^ompou~ds are sodium (C11-C15) alkyl benzene
; 25 sulphonates and sodium (C16-C18) alk~l sulphates.
Suitable nonionic detergent compounds which may be
used include i~ particular the reaction products of compounds
ha~ing a h~drophobic group and a reactive hydrogen atom, for
example aliphatic alcohols, acids, amides or aIkyl phenols
with alkylene oxides, especially ethylene oxide either alone
or with propylene oxide Specific nonionic detergent
compounds are al~yl (C6-C22) phenols-ethylene oxide
condensates, generally 5 to 25 E0, i.e. 5 to 25 units of
ethylene oxide per molecule, the condensation products of
aliphatic (C8-C18) primary or secondary linear or branched
alcohols with ethylene oxide, generally 6 to 30 ~0, and
products made by condensation of ethylene oxide with the
~137384
- 13 -
reaction products of propylene oxide and ethylenediamine.
Other so-called nonionic detergent compounds include long
chain tertiary amine oxides, long chain tertiary phosphine
oxides and dialkyl sulphoxides.
Mixtures of detergent compounds, for example mixed
anionic or mixed anionic compounds may be used in the detergent
compositions, particularly in the latter case to provide
controlled low sudsing properties. This is beneficial for
compositions intended for use in suds-intolerant automatic
washing machines. We have also found that the use of some
nonionic detergent compounds in the compositions decreases
the tendency of insoluble phosphate salts to deposit on the
washed fabrics, especially when used in admixture with
some soaps as described below.
Amounts of amphoteric or zwitterionic detergent compounds
can also be used in the compositions of the invention but this
is not normally desired due to their relatively high cost.
If any amphoteric or zwitterionic detergent compounds are used
it is generally in small amounts in compositions based on the
much more commonly used synthetic anionic and/or nonionic
detergent compounds. For example, mixtures of amine oxides
and ethoxylatednonionic detergent compounds can be used.
Soaps may also be present in the detergent compositions
of the invention, but not as the sole detergent compounds.
The soaps are particularlyuseful at low levels in binary
and ternary mixtures, together with nonionic or mixed
synthetic anionic and nonionic detergent compounds, which
have low sudsing properties. The soaps which are used are
the sodium, or less desirably potassium, salts of C10-C24
fatty acids. It is particularly preferred that the soaps
should be based mainly on the longer chain fatty acids
within this range, that is with at least half of the soaps
having a carbon chain length of 16 or over. This is most
conveniently accomplished by using soaps from natural sources
such as tallow, palm oil or rapeseed oil, which can be
hardened if desired, with lesser amounts of other shorter
` 1~37384
_ ~4 _ C.1057
chain soaps, prepared from nut oils such as coconut oil
or palm kernel oil ~he amount of such soaps can be
up to about 25% by weight, ~rith lower
amounts of about 0.5% to about 5% being generally sufficient
for lather control. Amounts of soap between about ~/o and
about 2~/o~ especially between about 5% and about 15%~can
advantageously be used to give a beneficial effect on
detergency and reduced levels o~ incrustation.
Apart from the essential detergent active compounds and de-
tergencybuilders,the detergent compositions used intheprocess of
the inve~tion can contain any of t~e conventional additives
in the amounts in which such materials are normally employed
in fabric washing detergent compositions. Examples of these
additives include lather boosters such as aIkanolamides,
particularly the monoethanolamides derived from palm kernel
fatty acids and coconut fatty acids, lather depressants such
as alkyl phosphates, waxes and silicones, antiredeposition
agents such as sodium carboxymethylcellulose and polyvinyl
pyrrolidone optionally copolymerised with vinyl acetate,
oxygen-releasing bleaching agents such as sodium perborate
and sodium percar~onate, per-acid bleach precursors, chlorine-
releasing bleaching agents such as trichloroisocyanuric acid
and alka~li m~tal salts of dischloroisocyanuric acid, fabric
softenin~ agen~s, inorganic salts such as sodium sulphate,
sodium carbonate and magnesium silicate, and, usually present
in very minor amounts, fluorescent agents, perfumes, enz~mes
such as proteases and amylases, germicides ~nd colourants.
It is particularly beneficial to include in the
detergent compositions an amount of sodium perborate,
preferably between about 1~/o and ~/0, for example about
15% to about 3~/o, by weight. It has been ~ound that the
bleaching action of sodium perborate is boosted under
highly alkaline conditions which also give optimum detergency
and building action from the orthophosphate. ~hus,
it becomes possible to achieve improved bleaching propertles
by using the same levels of sodium perborate as normal;
or decreased levels of sodium perborate can be used to give
" ~37384
- 15 - C.1057
equal bleaching properties to those of conventional products
with higher levels of perborate and sodium tripolyphosphate
as the sole detergency builder. ~he latter option can also
be used to further decrease the raw materials costs of the
compositions, if a cheap filler is used in place of part
of the sodium perborate.
It is desirable to include one or more antideposition
agents in the detergent compositions of the invention, to
decrease the tendency to form inorganic deposits on washed
fabrics. It appears that the effective antideposition
agents are materials which stabilise insoluble calcium
orthophosphate particles and thereby inhibit their
deposition onto the fabrics. ~he most effective anti-
deposition agen~s are anionic polyelectrolytes, especially
polymeric aliphatic carboxylates. ~he amount of any such
antideposition agent can be from about 0.01% to about 10/o
of the compositions, but is normally from about 0.1% to about
5% by weigh~, preferably from about O.~/o to about 2/o by
weight of the compositions.
Specific preferred antideposition agents are the ~lkali
metal or ~moniwm, preferably the sodium, salts or homo-
and co-polymers of acrylic acid or substituted acrylic acids,
such as so~iium polyacrylate, the sodium salt of copolymeth-
acrylamidejacrylic acid and sodium poly-alpha-hydrox~acrylate,
25 salts of copoly ers of maleic anhydride with ethylene, acrylic
acids vl~vl~ethylether allyl acetate or styrene,especially 1:1
copol-~mers, and optionally with partial esteri~ication of the
carbox~l groups. Such copolymers preferably have relativel~
low molecular weights, eg in the range of about 1,000 to
50,0QO. Other antideposition agents include the sodium salts
of polymaleic acid, polyitaconic acid and polyaspartic acid,
phosphate esters of ethoxylated aliphatic alc~hols, poly-
ethylene glycol phosphate esters, and certain phosphonates
such as sodium ethane-1-hydroxy-~,1-diphosphonate, sodium
ethylenediamine tetramethylene phosphonate, and sodium 2-
phosphonobutane tricarboxylate. Mixtures of organic
phosphonic acids or substituted acrylic acids or their salts
`` 1~ 37384
_ 16 - C.1057
with pro-tective colloids such as gelatin may also be used.
~he most preferred antideposition agent is sodium poly-
acrylate having a ~ of about 10,000 to 50,000, for example
about 20,000 to 30,000.
It is also possible to include in the detergent
compositions of the invention minor amounts, preferably not
more than about 20% by weight, of other non-phosphate
detergency builders or sequestrant builders. ~his is of
particular benefit where it is desired to increase detergency
whilst using particularly low levels of the e~sential
alkali metal tripolyphosphate and alkali metal orthophos-
phate builders, so as to achieve especially low phosphorus
contents in the detergent compositions. Examples of such
other detergency builders are amine carboxylates such as
~5 sodium nitrilotriacetate, sodium carbonate, sodium amorphous
or crystalli~e aluminosilicate ion-exchange materials,
sodium citrate and soap, which can function as a
detergency builder, as discussed above. However, such other
builder materials are not essential and it is a particular
benefit of using the mixed alkali metal tripolyphosphate
and orthophosphate that satisfactory detergency properties
can be achieved at lower total phosphate levels than
hitherto considered necessary without other detergency
builders.
It is generally also desirable to include in the
compositions an amount of an alkali metal silicate,
particul~rly sodium ortho-, meta- or preferably neutral or
alkaline silicate~ ~he presence of such alkali metal
silicates at levels of at least about 1% and preferably
from about 5% to about 15%, by weight of the composition,
is ad~antageous in decreasing the corrosion of metal parts
in washing machines, besides giving processing benefits and
generally impro~ed powder properties. ~he more highly
aIkaline ortho- and meta-silicates ~ould normally only be
used at lower amounts within this range, in admixtu~e with
the neutral or al~aline silicates.
"~ 1137384
_ ~7 _ C.1057
.. . . . ... . . . _ .. . . _ . . .. .
~ he compositions of the invention are required to be
alkaline, but not too strongly aIkaline as this could result
in fabric damage and also be hazardous for domestic usage.
In practice the compositions should normally give a pH of
from 9 to 11 in use in aqueous wash solution. It is
preferred in particular for domestic products to have a
minimum pX of at least 9.25 and especially a pH of 9.5 or
over, as lower pHs tend to be less effective for optimum
detergency build;ng, and amaximum pH of ~0.5, as more highly
aIkaline products can be hazardous if misused. The pH is
measured a-t the lowest normal usage concentration of 0.1%
w/v of the product in water of 12H (Ca), (~rench permanent
hardness, calcium only) at 50C so that a satisfactory
degree of aLkalinity can be assured in use at all normal
product concentrations.
The pH of the detergent compositions in use is
contrclled by the amount of orthophosphate and
any other aLkaline salts such as alkali metal silicate,
sodium perborate and sodium carbonate present. The
presence of such other alkaline salts, especially the
alkali metal silicates, is particularly beneficial,
because the alkalinity of the aIkali metal orthophosphate
i5 diminished in hard water due to precipitation of the
calcium salt. In addition the alkali metal tripolyphosphate
is mcre stable and resistant to hydrolysis under moderatel~
alkaline conditions. ~he other ingredients in the aIkaline
detergent compositions of the invention should of course be
chosen for alkaline stability, especially the pH sensitive
materials such as enzymes.
~0 The detergent compositions of the invention are
prefer~ably made in particulate form, by admixtuIe of a
spray dried base powder and treated tripoly-
phosphate. However, if desired, the detergent compositions
may be compressed or compacted into tablets or blocks, or
~5 otherwise treated for example by granulation, prior to
packaging and sale. To~protect the compositions during
~tora~e it may be desirable to use moisture impermeable
1137384
- 18 - C.1057
packaging for example in plastic or fabric sachets
containing premeasured doses of the detergent
compositions for washing machine usage.
The invention is illustrated by the following
Examples in which parts and percentages are b~ weight
except where otherwise indicated~
EXAMPIE 1
Detergency tests were accomplished to determine the
effect of delayed addition of sodium tripol~phosphate,
using a nominal formulation of:
%
~odium alkyl benzene sulphonate 6
Nonioni~ detergent compound 2
(C12 alcohol - 12 E0)
Soap 3
Sodium tripolyphosphate 5
~odiwm orthophosphate 11
Sodiu~ sulphate 25
Sodium silicate 10
Magnesil~ silicate
SCMC
Sodium perborate 23
Water (and minor additives) to 100
added ~ith the other ingredients or after a specified
dela~.
Terg~o-tometer tests were undertaken, using a 25 minute
wash cycle wi~h a product concentration of 10g/1 in water at
95C and 22 German hardness. ~he level of inorganic deposi-
tions (ash) wasmeasuredfor the cotton test cloths after 6
30 and 18 repeat wash cycles, using delays of 0,5,10 and 15
minutes after the other ingredients before addition of the
sodium tripolyphosphate,with the following results:
,,
. ~
~37384
- 19 - C.1057
Delay % ash
(Mins) 6 washes 18 washes
0 1.6 4.1
0.6 1.8
0.5 1.6
0.5 1.4
~ hese results show a marked reduction in the i~organic
deposition caused by the delayed tripolyphosphate addition.
Further detergency tests showed that there was no significant
difference in detergency caused by the delay, when using a
variety of different standard test cloths.
~he tests were repeated on alarger scale in a
Miele automatic washing machine using a product dosage of
200g in water of 22 German hardness, and the boilwash
cycle in which heating ta~es 30 minutes and the boil
continues for 20 minutes. ~he sodium tripolyphosphate
was added after 0,15,30 or 40 minutes, with the following
results on the inorganic depositions, which confirm the
benefit of delayed addition.
% ash
Dela~ 3 washes6 washes 9 washes 12 washes
0 2.1 4.2 6.3 8.2
1.4 2.8 4.4 6.2
3 1.1 2.4 3-6 4.7
25 40 -9 1.7 2.4 3.2
Detergency tests on varied test cloths in the same washes
again showed slightly improved wash results for the delayed
addition of -the sodium tripolyphosphate, but within the
margin of experimental error.
1137384
- 20 -
EXAMPLE 2
Experiments were carried out in a Tergotometer to
demonstrate the effect of tripolyphosphate on fabric
incrustation. A detergent composition having the
5 following formulation was made up by mixing solutions.
Insredient % by weight
Alkyl benzene sulphonate 6
Nonionic detergent active 2
Socium soap (70/30 coconut/
hardened tallow) 3
Sodium alkaline silicate 10
Sodium sulphate 15
Sodium chloride 9.5
Sodium orthophosphate,
Sodium tripolyphosphate,
Sodium polyacrylate and water balance
Fabrics were washed using this composition to which
orthophosphate, tripolyphosphate and polyacrylate were added
as set out below. The wash conditions were 40FH wash
water hardness (Ca:Mg 4:1), 30FH flood and hand rinse
water hardness (Ca:Mg 4:1), wash temperature 90C, wash
time 20 minutes, flood 2 minutes, rinse 5 minutes and
product dosage 14 g per litre. The results achieved
are set out in the following table.
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~.~37384
- 21 _ C.1057
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