Note: Descriptions are shown in the official language in which they were submitted.
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1'~3~79~
The present invention relates to new detergent
compositions suitable for washing dishes in a washing
machine, and a process for preparing themu
The washing of dishes in a machine invoives both
the detergent action of the ~ashing agent and the mechani-
cal action of water. Apart from its detergent action,
the washing agent must also have a disinfectant capacity
and water-softening properties. The washing agent must
therefore possess strong detergence but also its composi-
tion must be such that it does not cause the formationof foams ~hich are harmful to the mechanical action of
water. This is why the ~ashing agent compositions
consist in a known manner of:
- a softening agent, generally chosen from the
class of polyphosphates. (Among the polyphosphtes used,
mention can be made of sodium tripolyphosphate, sodium
hexametaphosphate and sodium pyrophosphate, as well as
the corresponding potassium polyphosphates);
- an alkalinity-producing agent mainly consist-
ing of a sodium metasilicate in its anhydrous form or inits pentahydrate form. ~In a known manner sodium silicate
may be partly replaced by sodium carbonate, sodium sul-
phate, or sodium hydroxide);
- a non-foaming surface-active agent of the non-
ZS ionic type, chosen from the following classes of products:ethoxylated linear alcohols, condensate of ethylene oxide
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~ith propylene oxide, alkoxy amines, polyethoxyethers
of fatty alcohols, ethoxylated alkylphenols, or phosphor;c
esters of fatty alcohols. (Preferably, for reasons of
effectiveness, biodegradabil;ty and cost, a surfase-active
agent is chosen from the class of ethoxylated linear alco-
hols); and
- a disinfectant.
The disinfectant used, which releases active
chlorine, is generally a sol;d chlorine-based product of
the chloroisocyanurate derivative eype~ This is most fre-
quently a sod;um or potassium salt of dichloroisocyanuric
acid.
Until the present time, the following were used in
practice: anhydrous sodium dichloroisocyanurate titrating
at 63X of active chlorine, a sodium dichloroisocyanurate
dihydrate titrating at 56X of active chlorine, anhydrous
potassium dichloroisocyanurate titrating at 59X of active
chlorine, potassium dichloroisocyanurate monohydrate tit-
rating at 56X of active chlorine or calcium dichloroiso-
cyanurate tetrahydrate titrating at 56X of active chlorine.The active chlorine is defined as being the oxidising
capacity due to the positive chlorine. To understand
better to what pos~tive chLorine corresponds it should
be recalLed that chlorine present in the chlorinated deri-
vatives described above is bound to a nitrogen atom andis present therein in the oxidation state + 1, that is
to say Cl+ During the oxidation-reduction process a Cl+
ion combines with two electrons to be converted into the
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Cl (chloride) state. Two equivalents of an oxidising
agent are released, which correspond to 71 9 of elementary
chlorine although the atomic weight is only 35.5. This
also means that an atom of Cl+ has the same oxidising
capacity as a molecule of elementary chlor;ne Cl2.
Amongst the other chlorinated disinfectants of the
chloroisocyanurate family, there is one which titrates at
approximately 91X of active chlorine: trichloroisocyanuric
acid. It would therefore be advantageous to be able to use
it, given its high percentage of active chlorine. Unfor-
tunately, until the present time it could not be used, as ;t
was too reactive towards the other components of the washing
agent compositions, in particular towards the surface-active
agents. ~ashing agents containing trichloroisocyanuric acid
are unstable in storage and they lose significant quantities
both of chlorine and of surface-active agents through mutual
destruction.
A means of stabilising trichloroisocyanuric acid
has now been found, in particular of stabilising it for
manufacturing washing agent composit;ons which are stable in
storage and suitable for washing dishes in a washing
machine.
~ he present invention relates to a new stable wash-
ing agent composition suitable for washing dishes in a
washing machine, containing a softening agent chosen from
the polyphosphates, an alkalinity-producing agent chosen
from the sodium silicates, a nonionic surface-active agent
and a chloroisocyanurate derivative, characterised in that
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the chloro;socyanurate der;vat;ve used is trichloroiso-
cyanuric acid coated with the aid of a paraffin wax
employed in a concentration of 1 to 10% by weight relative
to the weight of the acid.
It has been found that paraffin waxes were com-
patible with tr;chloroisocyanuric ecid. Moreover, when
used in relatively small amounts, they make it possible to
produce good stabilisation of the acid. Furthermore, they
are dispersible under the washing conditions, that it to
say in aqueous media at a temperature of 50 to 60C.
The paraffin waxes consist of a mixture of solid
hydrocarbons with a high molecular weight (for example
C36H74) which have a melting point below 60C and above
40C, and a viscosity at 100C below 6 centipoises.
They are employed in a concentration of 1 to 10X by weight
relative to the trichloro;socyanuric acid, preferably in a
concentration of 3 to 5X by weight. Above 5X diffirulties
appear in carrying out the coating and it is necessary to
modify the conditions in order to obtain a suitable coating.
The use of quantities greater than 10X does not produce an
appreciable improvement in the storage stability of the
washing agent compositions. The use of quantities below 1%
results in too poor a stabilisation of the ac~d.
The wash;ng agent composltions which are the sub-
Z5 ject of the invention are manufactured by first carryingout the coatlng of the trichloroisocyanuric acid with the
aid of paraffin waxes. This coating is carried out in any
kind of industrial mixer, such as a drum mixer, preferably
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a mixer fitted with a heating device. It is also possible
to employ a rotary mixer of the concrete-mixer type in which
the molten wax is sprayed on the acid heated to a temperature
in the region of 50C. The temperature of use permits good
distribution of the paraffin waxes, which solidify on cooling.
The wax-coated trichloroisocyanuric acid is then mixed in
another mixer with the other components of the washing agent.
The quantities of the various components other than
the paraffin employed for the manufacture of the new washing
agent compositions which are the subject of the invention are
employed in conventional weight ratios. The softening agent
chosen from the polyphosphates is employed in a concentration
of 25 to 60% by weight and preferably 40 to 50% by weight
relative to the weight of the composition.
The alkalinity-producing agent chosen from the
sodium silicates is employed in a concentration of 30 to 70%
by weight and preferably 40 to 60% by weight relative to the
weight of the composition. In a known manner, sodium
silicate may be partly replaced with sodium carbonate,
sodium sulphate or sodium hydroxide. The nonionic surface-
active agent is employed in a concentration of 0.5 to 4% by
weight and preferably in a concentration of 1 to 3~ by weight
relative to the weight of the composition. Th~ trichloro-
isocyanuric acid coatecl with the aid of paraf~in waxes is
employed in a concentration of 0.5 to 5~ by weight and
preferably 1 to 3% by weight relative to the weight of the
composition.
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The following examples illustrate the present
invention.
EXAMPLE 1
Trichloroisocyanuric acid is f;rst stabil;sed
w;th the aid of paraffin ~axes ;n the follo~;ng manner:
The acid ;s heated to a temperature of 50C
and is then placed ;n a pill-coater. Wh;le the coater
rotates, paraff;n waxes are sprayed from above by
means of a spray-gun. The temperature of use perm;ts
a good distr;but;on of the waxes, wh;ch sol;d;fy on cool-
;ng. The paraffin waxes employed have a melt;ng point
below 60C and a viscosity at 100C of less than 6
cent;stokes. Var;ous m;xtures of ac;d and ~axes are
produced by us;ng vary;ng percentages of paraff;n waxes.
The m;xtures obta;ned in th;s ~ay are employed for the
manufacture of wash;ng agent composit;ons.
Wash;ng agents hav;ng the follow;ng compos;t;on
are prepared (parts are expressed in parts by we;ght):
- sodium tr;polyphosphate: 5û parts,
- sodium metas;l;cate (anhydrous or 5H20 hydrate):
50 parts,
- PLURAFAC RA 43 ~ethoxylated nonion;c surface-active
agent manufactured by the company PCUK): 2 parts,
- trlchloroisocyanur~c ac~d coated with paraff;n
waxes: 2 parts.
A prem;x of sod;um tripolyphosphate and non;on;c sur-
face-active agent is first made in a mixer of a rotary type.
A homogeneous mixture is obtained after 20 m;nutes. The
metas;l;cate is then added to the m;xer. After 20 min-
~ra~e ~1~rl~
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utes the coated trichloroisocyanuric acid is added. The
whole composition is then le~t in the rotating mixer for 20
minutes. The percentage of chlorine determined by iodometry
in the washing agent composition is then 1.65~.
The washing agent composition prepared in this
way is placed in plastic bags closed with a non-hermetic
closure. The bags are stored in a controlled environment
oven under the following conditions:
- temperature: 40C.
- relative humidity: 80~.
Samples are withdrawn after a storage period of
between 1 and 3 months and the residual chlorine is deter-
mined by iodometry. Table 1 shows the results obtained
after 50 days' storage for washing agent compositions
prepared from anhydrous sodium metasilicate and from
trichloroisocyanuric acid coated with the aid of paraffin
waxes employed in various percentages (by weight). The
results relating to the remaining chlorine are expressed as
percentages relative to the original chlorine.
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TA~LE 1
TRICHLOROISO- Wash;ng agent
CYANURIC ACID composit;on
7. of remaining
chlorine
Not coated with
paraffin ~axes 39
Coated with 5X
of paraffin waxes
having a melting
point of 50-52C 81
Coated with 5X
of paraff;n waxes
having a melting
point of 40-42C 78
Coated with 5X
of paraffin waxes
having a melting
point of 58-60~C 68.5
EXAMPLE Z
Example 1 is repeated but using sodium meta-
silicate pentahydrate, instead of the anhydrous meta-
silicate as ~n Example 1, for the preparation of the
washing agent compositions. Table ~ collates the results
obta~ned.
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TABLE 2
Trichloroiso- Washing agent
cyanuric acid composit;on
% of remaining
chlorine
Not coated with
paraffin waxes 14
Coated with SX
of paraff;n waxes
having a melting
point of 50-52C 38.5
Coated with 5X
of paraffin waxes
hav;ng a melting
po;nt of 40-42C 26.5
Coated with 5X
of paraffin waxes
having a melting
point of 58-60C 30
2C EXAMPLE 3
Examples 1 and 2 are repeated using paraffin waxes
having a melting point of 40-42C. Samples are withdrawn
after a storage period of 80 days. 'Table 3 shows the
results obtained for washing agent compositions prepared
either from anhydrous sodium metasilicate or from sodium
metasilicate pentahydrate.
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TA8LE 3
X of remaining chlorine
Tr;chloroiso- Washing agent prepared Washing agent
cyanuric acid from anhydrous sodium prepared from
metasilicate sodium meta-
sil;cate
pentahydrate
Uncoated acid 20 10
Acid coated with
1% of waxes 30 15
Acid coated with
2% of waxes 60 25
Ac;d coated with
5X of waxes 78 26.5
Acid coated with
10% of waxes 78 27
