Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
W0 93/12843 2 1 ~ ? 1 i7 Pcr/us92/ll~22
GRANULAR PER~ARBONi~TE LAUNDRY BLEACH CONTAININ6 LAYERED SILICATE STABILIZER
~h~~
The present inv~ntion relates to blea~hir~g r~mpositions f or
laundry. Granular lalmdry bleaching cc~mpositions are
described which comprise percarbonate as the bleaching
specie, said c:ompositions beirlg stable upon storage.
~
The inorganic perhydrate blea ::h most widely used in the
context of laundry bleaching is sodi~am perbsrate in the
f orm of either the monohydrate or tetrahydrate . However,
con ::erns abe~ut the lmpact of boron salts on the envirorlment
have led to an increas ing int~rest in other perhydrate
salts, o~ which sodium percarbonate is the most r~adily
availabl~ . -
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Detergent :ompositions containing sodium percarbonate are
known in the art. Percarborlate salts, partic:ularly sodium
percarbonate, are attractive perhydrates for use in
detergent composition because they :lis~;olve r~adily in
water, are weight efficient and, after giving up their
available oxygen, provide a u~;e~ul source of c:arbonate ions
f or detergency purposes ~
However, the inclusion of percarbonate salts in detergent
cc~mpositions has been res . ricted ~it~er~o by th~ r~lative
instability of the bl ach both as~is and in use. Sodium
percarbonate loses its av~ilable oxys~en at a signif icant
rate in the presence of ion~; o~ heav~r metals suc:~ as iron;
copper and manganese and also in the presenc . o~ moi~tur~,
the~;e ef f ects being acc:ele;rated at temperatur~s in exce&;~;
of about 3 0 C .
Moisture and h~a~y metal ion~ are un2voidable components of
conventional granular laundry treatment co~apcssiti~ns. Al~;o
pQrcarbunate dec~mposition du~. to ~aoisture becomes ~ore o~E
an issu~ during sto~age as laumdry tr~a~m~nt procluct~; ara
oft~n stor~d in humid environ~Dent~; wh~n th~ procluct picks
up moisture. This has result~d in ~nargin~lly acceptable
perc:arbonate bleach stability un~r Northern Europ~an
summer con~itior~s, where the average maximum temperature
over the hottest months is from 21C to 25C, arld
unacceptable stability under temperatllres hi~her than this.
Such conditions are f ound in the Middle East and Ss:)uthern
~sia and also in Southern Europ~ where average maximu
temperature~ are in the 27C to 33C range for the ht~test
summer month.
There has theref ore been much activity by workers in the
- field to increase percarbonate stability so as to mak~ it a
viabl~ component of detergerlt f ormulations . This activity
has tendes3 to concentrate on the protection of the
WO 93/12$43 2 ~ . 7 PCT/US92/1 1222
perc:arbonate by coating the crystal 1 ine product or ~y
inclusion of stabilising agents during its manufacture, or
both. Thus, while it has proved possible ts:~ incorporate
percarbonate salts in conventional deterg~nt compo-~ition
so as to have acceptable percarbonate stability over
periods ref lecting normal produ5t shelf liJ~e, the
percarbonate salts have proved ::omplex and ~xpensiv@ to
manuf acture . This has restrict~d their broadscale
utilisation, as evidenc:ed by the relatively s~all number of
commercially available products containing percarbonate.
It is therefc)re an object of the present inver1tion to
pre~vide a granular laundry bleaGhing compc)sition
~-~ incorporating an alkali metal percarbonate ~leach, said
bleach displaying :Lmproved ~tabilityD
It is a ~Eurther obj ect of the present inventioll to proYide
a granular laundry bleachinq compositiQn ince~rporating an
alkali meta.l percarbonate ble;~c:h displaying improved
stability, in which the percarbonate blea~h does ne~t
require complex protectiorl techniques.
It has now been ~ound that these obj ect~ could be ~et by
f s~nnulating a composition coJnprising an alkali metal sa~t
of p~rcarbonate to~ether with a crystalline lay~r~d
silicate or mixtures thereof.
Granular bleat:hir~g compositions comprising percarbonate
have been desc:ribed for instance in FR 2, 385, 837, US
4, 428, 914 and GB 1, 553, 505. Crystalline layered silicate
and their method5 of preparation have been described for
instance in EP-A-164 ~14, DE-A-34 17 649 and l)E-A-37 42 043
arld their application to the f ield of laundry treatment ~as
been descri~ed in applicant ' s copending British
applicatiorls GB 90 21 761. 3, GB 90 18157 . 9 and
GB 91 08639 . 7 .
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The composition5 according to the present invention also
allow adequate control of the pH in the bl~achin~ liquor,
giving appropriate balance between bleachis~g performance
and f abric: saf ety .
Summar~of ~ e inventiorl
CompGsitions as:cording to the present invention are
granular bleaching compositions comprising Dlore than 209c
and Ul? to 80~6 by weight of the total compo~;ition of asa
alkall me~al s~lt of percarbc~Jlate h7 each and from 5% to 80~c
by weight of the total c:omposition of a crystalline layered
silicate of formula Na~Six02x+1.~H20 wherein M is sodium or
~-~ hydrogen "c is a number cf fro~n 1. 9 to 4 and y ' s a number
oP from 0 to 20, or mixtures thereof. Pr~ferred
compositions herein further c:~prise aal a~hydrous
acidifying ager~t, prE~f~rably citric: acid.
etailed dese:~iptioL~
A~ a f ir~t e~s~ntial c:omponen~ ha co~o5ition!~ according
to t~e pr~sent invention ~o~pris~ an alkali ~etal salt of
p~rcarbonate, pre~erably sodiu~ percarbonat~ Sodiu~
percarbonate is available commercially as a cry~;t21lline
solid. Most c:o~erc:ially available material includ~s a low
level o~ a heavy metal s~questrant such as EI~TA, 1-
hydroxyethylid~n~ diphosp~oslic ac:id (HEDP) or an
amino-phosphonate, t~at is incvrporated duria~g 2~e
manuf acturing process. Fs:~r the purpose~ o~E the pr@~ent
inventiorl, the perc:arbclrlate c:an be incorporated into
detergent composition~ without addi~ional protection.
Whilst heavy metals presl2nt in the sodium carbonate used to
manuf acture tlhe percarbonate c~n b~ controlled by the
inclusion of se~uestrants in the reaction mixture, it is
pref erred that the percarbonate be protected f rom heavy
WO 93/12843 ~ U 3 i; PCI/US92/1122
metals present as impurities in other ingredients of the
product O It has been f ound that the total level of Iron,
copper and Manganese ions in the product should not excç~ed
~5 ppm and pref rably should be les~ than 20 ppm in order
tc~ avoid an unacceptably adverse ef f ect on perc:arbonate
stability ~
The composi~ions ac:c:ording to the pr~serlt invention
c:omprise moxe than 2 0% by weight of the total composil:ion
of percarbonate, up to 80% by weight of the total
compositiorl, preferably ~rom 409~ to 50%.
The s~cond ess@ntial t:omponer:t of the inv@ntiDn is a
~-~ crys~alline layered sili~ate. The c:rystalline layered
silicates suitable for u-ce herein are s: the granular
f ormul2
NaMSix02x+l Y~20
wherein ~ is sodiuDI or hydrogen, x is a number frola l. 9 to
4 and y is a nu~b~r from 0 to 20, or mixt~res 'chereofO
Crystalline layç~r~d sodium :ilic:ate~3 of thi~; type are
disclosed in EP-A-~ 64 514 z~nd methods for their prepara~isn
are disclo~gd in DE A-34 17 649 a~3d DE-A-37 4~ 043. Fs:~r
the purposes of tha present invention, x in tll~ gen~ral
f ormula abov~ h~s a value of 2, 3 or 4 and is pref erably 2 .
More pref erably M i~ æodium and y is 0 and pref erred
examples of this formula comprise the Q~ and S' fE:~rms
of Na2si2o5 These materials are available from Boechst AG
FRt; as respectively NaSKS 5, NaSKS-7, NaSKS ll and NaSKS 6.
The most preferred material is 5'- Na2Si205, 11~aSKS-6.
Crystalline layered silicates are incorporated eith~r as
dry mixed solids, or as solid components of agglomerates
with o~her compone~ats.
WO g3/12843 PCr/US92/11222
1 ~",.;`, i7 6
The oompositions according to the present irlvention
comprise from 5% to 80% by weight of t~e ts~kal composition
of said crystalline layered silicates or mixtures thereo~,
preferably ~rom 15% to 25%.
As an optional but highly pr~f erred component, the
compositions according to the present invention further
c:omprise an anhydrous acidifying agent or ~ixtur~s thereo~.
The purpose of said acidifying agent i~: to c:o3~tr0l the
alkalinity generated by the percarbonatP in the bleaching
liquor. Said agent need to be inc:orporated in the produc~
in an anhydrous form, and to have a good ~;tability in
oxi!tlizing environm~nt. Suitabl~ anhydrou~ acidifying
agents f or u e hereir~ are carboxylic acids suc:h a~; citric
acid " succinic acid, adipic ac:id, glutaric: acid, 3
chetoglutaric acid, citramalic: acid, tartaric acid and
maleic at:id. Other suitable ac:idifying agents include
sodium bicarbonate, sodium s~ arbonate and silicic
ac:id . Highly pref ~rr~d f or u~;~ her~in is c:itric acid .
Indeed, citric acid is c:o~nercially availaJ~le in anhydxou~;
i~on~, it additio~ally acts as a builder and a ch~lant, and
it is ~aiod~radable. The compo~itions ac:cordirlg to th~
pre~;ent inverltion comprise from up to l5% by wQig~t o~ t~e
total composition of anhydrous citric ac:id, pre~era~ly fro~la
29~ to 8%, most pre~erably about 5%.
Compositions in accordance with the in~vention s::an also
comprise csp~ional ingredients such as optical bri~hteners,
anti dusting agents such as olef ines and waxes, enzymes,
c:helants, dispersants, surf actal~ts, soil release agents,
photoaetivated bleach2s such as Zn phthalocyanine
sulphonate, dyes, pi~nents and perfumes are examples of
suc:h optional in~redients and can be added in varyir~g
amounts as desired.
.. 7
WO g3/12843 P~r/US92/11222
Optional but highly preferred ingredient are peroxy
car~oxylic acids bleach or precursor~ thereof, commonly
referred to as bleach activa~ors, which are pre~erably
added in a prilled or a~glomerated form. Examples of
suitable compounds of this type are disclosed in British
Patent GB 1 586 769 and ~B 2 143 231 and a method for their
formation into a prilled form iB descrIbed in European
Published Patent Application EP-A-62 523. Preferred
examples of such compounds are tetracetyl ethylene diamine
tTAED3, sod~um 3, 5, 5 trimeth~l hexanoyloxybenzene
~ulphonate 9 diperoxy dodecanoic acid as descri~ed for
instance in US 4 818 425 and non~lamide of peroxyadipic
acid as described ~or inst~nce in US 4 2~9 201 and n
nonanoyloxybenz~nesulphonate (NO3S)~ and acetyl triethyl
citrate (ATC) such as describ~.d i~ European Patent
application 91~70207.7.
~he compositions according to the pr~sent invention
naturally comprise inorganic f~ r salts such as alkali
m@tal carb3nat~s bicarbonates and sulphates. Such fillers,
for in~t~nce sodium ~icar~onate, may also act as acidify.ing
age~t a~ dQscribed herein above. Accordingly, ~odium
pQrcarbonate i~ a preferred filler ~aterial for.use herein~
Th~ compositions according to the presen~ invention can be
made by a variety of methods well known în the ar~,
including dry-mixing, spray dryin~, agglomeration and
granulation and combinations thereo~.
The compositlons according to the present invention can be
prepared wit~ diffexent bulk d~nsities, from conven ional
granular products to s~-called "conc~ntrated" products
(i.e. with a bulk den~ity above 600g/l).
wa~93/12843 ~''J i ~ i I PCr/US92/11222
Examples
1 ) Part A
The foll~wing ~xamples will illustrate t~e present
invention. The fe~llowing granular compc~sitioTIs ar~ m~de by
dry-mixing the listed ingredients in t~e listed
proportion~
Co~positions 1 2 3 4 5 6
Sodiu~ p~rcarbonate :40.0 35.û 54.0 55.0 46.0 47.0
TAED : 8.7 7.6 11~7 - 9.5
Silicate lsyeredl SXS-6: 25.0 30.0 20.0 lO.0 18.0 20.0
Anhydrous citri~ acid : 10 . 0 12 . 0 12 . O S . 0 5 . 0 5 . O
'Sodiu~ sulphate : 15 . 3 14 . 3 1. 0 20 . O O . 5 15 . O
Sodium bica~onate : - - - 5.0 18.0
NOBS : - - - - - 10 . 3
~inors :_up to 100 ~ _ :
The foll~wing co~npo~itions wer~! ~ade by mixing the li.ted
inç~ients in the li~ted proportiorl~. The self ~e~ting
rates of th~ produ t~; w~re ~nonitor~d a~ follows. q!h~
product is ~ade and put in a bottle. The bottl~ i~ n
put in an o~r~n which is heated up to 70c. A prob~ in the
product allows to monitor the temper~ture of the produc:t.
As soon as the produc:t reach~s 7 û c, th2 bottle i~ c~ rad
and t~e sy~;tem i~ lated in aLn adiaba~ictthenno bell
which ~aint~ins the t~peratu:re o f the oven cog~ ta~t at
7 0 c as bov~ . This places t~e product in adiabati
conditions and f rom thereon, the temperature of ~e produc:t
i~ monitored. The temperature inc:rea~e thus m~asur~d is
due tc7 the self-heating c~f the product (runaway r~ctiorl).
The re-cults below list t~ree self heating rates, all irl
c/hour: SHRl is the av~rage temp~rat:ure incr~a~;e ~n~as~ed
during the f irst two ho~s o~ adiabakic c:l~nditio3ls; SHR2 ic
the average temperature increase measured during the tllree
W0 93~12843 2 1 ~ P~/US9~/11222
following hc~urs, and SHR3 is the average temperature
increase measured beyond 5 hours. The ta}:~le below lists
the results obtained for various c~mpositions, witl~ and
withou~ crystalline layered 5i `1 icate. In some c:ase the
runaway reaction was out of control and ~xperiment~ had t:o
be interrupt~d f or saf ety r~a~;ons . Such experime~t . are
~arked "~oc" (out of cvntrol).
Compositions 7 7a 13 8a 9 9a
Sodium percarbonate 47.0 47.0 ~7.0 47.047.0 47.0
TAED 10.2 10.2 10.2 10.2 ").2 1û.2 -
S ilica~e SKS - 620 . O - - 20 . O - ~ 20 . O - -
Citric acid 10.0 10.0 8.0 8.0 8.0 8.0
Sodium Sulphate11. 7 31. 7 13 . 7 33 . 7 9 . 225~ . 2
Sodium bicarb~nace ~ --- --- 4.5 4.5
SHRl* 2.3 4.5 2.2 4.0 2.5 3.9
S~2** ~.6 8.9 0.6 ~.0 0.5 7.7
S~IR3*** 0 ooc 0 ooc 0 o~c
Co~apositiotls 10 lOa 11 11~1 12 12
Sodiw~l ~ercarbonat~ 47.0 47.0 47.0 47.047.0 47.0
TAED 10.2 10.2 10.2 10.2 10.210.2
Sil~c~te SKS-6 18.0 -- 20~0 -- 42.8 ~--
Citric acid 7 . 0 7 . O 5 . 0 5 . O
S~diu~ Sulphate16 . 7 34 . 7 16 . 7 35 . 7 - _42 . 8
Sodium blc~r~onate
5~R1* 2.7 4.1 2.~ 4.1 2.2 4.0
SHR2** 0.6 8.3 0.4 ~.2 0 310.8
SH1~3*** 0 ooc 0 ooc 0 ooc
Comments:
Compositions 7-12 show good thermal stability, and no ~emperature
inc:rease is reported after 5 hours storage and beyond. ~n t~a~
absence of crystalline layered silicate i.e. in co~positio~
7a 12a, self-heating rates measured were so high that experi~ents
had to b~ stopped for saf~ty purposes.
