CA2038189C

CA2038189C - Bleaching composition

Info

Publication number: CA2038189C
Application number: CA002038189A
Authority: CA
Inventors: Christophe Joyeux
Original assignee: Unilever PLC
Current assignee: Unilever PLC
Priority date: 1990-03-15
Filing date: 1991-03-13
Publication date: 1999-02-09
Anticipated expiration: 2011-03-13
Also published as: EP0447261B1; ES2069200T3; ZA911937B; DE69106908T2; JPH0762154B2; CA2038189A1; JPH05505207A; BR9106150A; EP0447261A1; GB9005873D0; WO1991013964A1; AU661269B2; AU7448591A; DE69106908D1

Abstract

A bleaching composition is a perfumed aqueous solution of alkali metal hypochlorite containing alkane sulphonate with alkyl ether sulphate and/or soap. Amine oxide and hydrotropes are unnecessary and the amount of amine oxide (if any) is limited to half the amount of other surfactants.

Description

- 2~3~9 BT.~AC~TT~G COMPOSITION

This invention relates to hypochlori-te-based aqueous liquid bleaching compositions.
It is well known to include both hypochlorite bleach and surfactant in the same compositions.
We have now found that useful properties, in particular useful combinations of properties, can be obtained using a mixture of specified anionic surfactants.
We have found that including alkyl ether sulph~te and/or soap in surfactants present enhances the ability of the composition to dissolve perfume. Of course the incorporation of perfume is generally desired for compositions intended for domestic use. We have also found that incorporation of some alkyl ether sulphate can improve the ability of the composition to remove a number of stains.
According to this invention there is provided a perfumed aqueous liquid solution of alkali metal hypochlorite, also containing a surfactant mixture comprising ; (i) an alkane sulphonate of formula R-S03M in which R is an alkyl group with 8 to 22 carbon atoms and either (ii) an alkyl ether sulphate of formula Rl- (OC2H4) n SO4M in which Rl is an alkyl group with 8 to 20 carbon atoms and n has a value in the range of from 0.5 to 12, and/or (iii) soap of formula R2CO2M where R2 is an alkyl or alkenyl group of 7 to 19 carbon atoms, each M denoting a solubilising cation;
the amounts of the said surfactants, by weight based on the whole composition, being i) alkane sulphonate 1 to 10%
ii) alkyl ether sulphate 0 to 3%
iii) soap 0 to 3%
but the total of (ii) and (iii) being 0.1 to 4%, the amount of amine oxide (if any) in the composition being less than half the content of other surfactants.
The composition is a clear liquid solution containing at least 0.1~ by weight of perfume.
Commercial supplies of alkali metal hypochlorite solution contain varying amounts of sodium chloride. We prefer to use hypochlorite solution which has a fairly low content of sodium chloride. We have then found it possible to prepare compositions which contain a substantial proportion of surfactant.
One category of surfactant which has been used extensively for (thickened) hypochlorite compositions is the amine oxides. The use of these is discussed in our UK patent 1329086 which explains that the amine oxides can function like a hydrotrope (although they are normally regarded as surfactants). We have found it unnecessary to include amine oxide or hydrotrope. It is 2~3~ 9 a feature of this invention -that -the proportion by weigh-t of any amine oxide is less than half the amount o~ other surfactant. Preferably amine oxide is entirely absent.
It is also preferred that compositions of the invention are devoid of hydrotropes such E~S urea, alcohols with up to four carbon atoms, ox short chain alkylaryl sulphonates, e.g. with no more than four carbon atoms in the alkyl group(s). If any such hydrotrope is present, the proportion by weight of it may be less than the amount of surfactants (other than amine oxide, if any) present, better less than half the amount of surfactants other than amine oxide. In any case, it is desirable to exclude urea and primary or secondary alcohols because these are not stable in the presence of hypochlorite.
; 15 The alkane sulphonate used in this invention has the formula:

where R is an alkyl group of 8 to 22. Preferably R has 12 to 22, carbon atoms and the solubilising cation M is preferably alkali metal. Preferably R is a secondary alkyl group. It may be br~nched but preferably is unbranched.
The amount of the alkane sulphonate lies in the range from 1 to 10~ by weight of the co~position. The amount may possibly be not more than 8%, e.g. 2% to 6%.
Alkyl ether sulphate useful in this invention has the formula:

R ~ (~C2H4)n OS03M

~0~:189 where M is a solubilising cation, especiall~ alkali metal, Rl is an alkyl group of 8 to 20, preferably 10 to 16, carbon atoms and n has an average value in the range from 0.5 to 12, better 1 to 6, even better 2 to 5.
may be primary or secondary, and preferably is unbranched.
Soap useful in this invention has the formula:
R2 C0,2 M
where M is a solubilising cation, especially alkali metal and R2 is an alkyl group of 7 -to 19, preferably 9 to 15, carbon atoms. Olefinic unsaturation should desirably be absent, for the sake of stability in the presence of hypochlorite.
The total amoun-t of soap and alkyl ether sulphate lies in the range from 0.1, preferably 0.2, to 4% by weight of the composition. If alkyl ether sulphate is present, the amount will generally be at least 0.1% by weight. Similarly, if soap is present, the amount will generally be at least 0.1%. The weight ratio of alkane sulphonate to the total of alkyl ether sulphate and soap is preferably from 1:1 to 10:1 better 2:1 to 6:1.
R, Rl and R~ can, but do not need to be, the same, but preferably R1 and R2C02 both have an average carbon chain length of 10 to 16 carbon atoms and may be predominantly of 12 carbon length.

The hypochlorite is desirably included in a quantity to provide from 0.1 to 8%, better 0.5 to 3~ or 5% of available chlorine, by weight based on the whole 2 ~ 3 ~

composition. It is ~esirable -to use hypochlorite in which the amount of available chlorine is at least twice the amount of any sodium chloride present. One supplier of suitable hypochlorite is Tahn and Mulhouse.
The composition will generally be alkaline. For this purpose alkali metal hydroxide may be included in a quantity between 0.1 and 1.5~ by weiyht of the composition.
The amount of perfume dissolved in the composition, made soluble by the presence of alkyl ether sulphate and/or soap may lie in the range from 0.1 to 1.0% by weight of the composition. Preferably the amount of perfume is up to 0.6 or 0.7%.
A preferred composition according to this invention may have constituents and quantities as set out below.
Preferred Percentage of Active Matter Secondary alkane sulphonate 1 to 6%
Alkyl ether sulphate 0.2 to 2%
Soap 0.2 to 2 Alkali metal hypochlorite 0.5 to 2 (expressed as available chlorine) Sodium chlorideless than 1-~, and also less than half the weight of available chlorine Sodium hydroxide 0.2 to 1.0%
Perfume 0.1 to 0.6 Waterbalance to lOO~

2~3~

Various other constituents are possible. Notable is 0.1 to 0.5% of alkali metal silicate. The pH of the composition is, suitably, greater than 11. This will give a lesser alkaline pH on dilution, especially when dilution is with hard tap water.
The invention is illustr,ated by the following Examples in which percentages are by weight based on the whole composition unless otherwise stated.

Example 1 A number of cornpositions were prepared using the following constituen's:
Secondary alkane sulphonate (SAS) with average 16-18 carbon atoms Linear alkyl ether sulphate (LES) in which the alkyl group has avera~e 12-13 carbon atoms and the average degree of ethoxylation is 3 Lauric soap Sodium hydroxide Perfume A sodium hypochlorite solution which had the following characteristics as supplied:

Available chlorineover 315 g/litre NaOH 10-20 g/litre Specif:ic gravity1-315 to l-320 NaCl 80 to 120 g/li-tre ~3~9 The various compositions were made up in distilled water. All compositions contained sufficient hypochlorite to yield 1~ available chlorine. I-t was noted whether the composi-tions were cloudy or clear.
Compositions and results are set out in the follo~ing Tables 1 and 2:

~- 2~3~89 o cr) In a o o I I

'C~
o ~O r1 (~ O I I I C~
~1 ~ o .1 ~ ~ O
In ~~ o I ~ I O

~rl ~_~
03 ~D
O r~ ~ r~
~ O ~
h . ~a~
0!:1 r-l O
r~ ~ ~ rl ~ O I I I C ) ,~
, E~ co CO O ~
~ ~ O I I r_ r~

O O ~ O
~_I r~3 0 1 1 ~ C~
a) :~ L
~- O t O ~ C ~~
Z ~-a L~ L~ ~J
O ~, .~ s a, o r~
G-~ ' ~
~ ~ ~ ~ ~ ~ L

- 2~3~

.~, .., co ~.o (a O r-l N a) r~
, r~ r~~ o I o I ~) r.
h Ir) O N
,, o~ / In ~ ~v ,r ~ r ~ (~ O I O O C) _l V
' ~
~ O N (~
O rl U~
(D O
~rl r-lN O O I O
~d It) N ~
O rl N O
t~ ~ ~ . ,~
N ~r ~ ~111'~ O I I O C.) . ~ ,~
s~ ~
o\O O ~1 N O
. . ~
CO r~N O I I O

O O N O
.--1 ~IN O I I O C.) ~-1 .~ ~
~,1 a ~-, Z;
o ~rl S Q O ~

C ---- ~ S ..
) ~r ~ ~r O
la u~ h ~ 1 ~ L

2~3~

Comparison of compositions 2, 3 and 4 show that increasing the amount of SAS from 2.0 to 2.8~ was not sufficient -to render the perfume soluble but addition of 0.26% soap did bring about solut;ion of the per~ume.
Composition 12 shows that addition of 0.26~ LES also brough-t about solution of the perfume. Compositions 5, 6 and 7 show the same effect at higher concentrations. Increasing the SAS level to 2.0 to 3.9~ was not enough to bring about solution of 0.3~ perfume but addition of 0.5~% soap did cause the perfume to dissolve.
The solubility of perfume is low when sodium hydroxide has been added as shown by composition 1.
Comparison of compositions 8 and 9 shows that increasing the level of SAS to 5~ was not enough to bring about the solution of perfume. Comparison also with compositions lO
and ll shows that addition o~ 0.5~ LES or 0.5% soap did dissolve the perfume.

Example 2 A number of compositions were prepared using the same constituents as in Example 1, although in addition all compositions included 0.~ sodium silicate. Compositions and results are set out in the following Table 3.

% by weight active matter Composition No: 13 14 15 16 17 18 19 20 Hypochlorite to yield available chlorine SAS 2.0 2.0 2.0 2.0 2.0 2.0 2.0 2.0 Perfume 0.15 0.20 0.20 0.20 0.30 0.30 0.40 0.40 Lauric soap - 0.10 0.20 0.40 0.40 0.50 0.70 . 0.80 LES 0.5 0.5 0.5 Sodium hydroxide 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Sodium silicate 0.2 0.2 0.2 0.2 0.2 0.2 0.2 0.2 Result: Clear Cloudy Clear Clear Cloudy Clear Cloudy Clear , 2~3~

Compositions 15, 16, 18 and 20 demons-~rate -that soap and LES can be used together to bring about -the solubilisation of perfume.

Example 3 Compositions were prepa;red using the same materials as in Example 1, without sodium silicate, and with the amounts of the materials as se-t out in the follo~ing Table 4.

~ by weight active matter Composition No: 21 22 23 24 Hypochlorite to yield available chlorine 1.0 1.0 1.0 1.0 SAS 2.0 5.0 5.0 6.0 Perfume 0.2 0.2 0.7 0.2 LES 0.5 2.0 2.5 1.5 Soap - 1.5 005 2.0 Sodium hydroxide 0.5 0.5 0.5 - All of these composi-tions were clear solutions.

Example 4 Compositions were prepared in distilled water using the same materials as in Example 1 without sodium silicate, and with the amounts of the materials as set out in the 2~3~1~9 following Table 5.

% active matter by weight Composition No: C D

Available chlorine1.0 1.0 Sodium secondary alkane sulphonate2.0 2.0 Alkyl ether sulphate - 0.5 Amine oxide Lauric soap Sodium hydroxide0.5 0.5 The compositions ware used to remove various stains by a standard procedure. 1 ml of the composition was applied to a plastic tile bearing the stain. The tile was rubbed with the composition 200 times, using a ~ch; n~. -to rub the tile. Each composition was used to clean three tiles bearing each stain. After the tiles had been cleaned in this way the effectiveness of cleaning was assessed by a panel of five evaluators whose assessments were averaged.
Composition D was found to be more effective than C
on stains which were oil, two types of glue, veyetable fat and red pencil.

2~3~9 Cleaning Efficiency Stain Best Worst Oil dag D C
Glue D C
Glue for label D C
Vegetaline D C
Red pencil D C

Example 5 The compositions of Example 2 were diluted with distilled water and used to wash a plastic tile. This was allowed to dry and the presence of streaks on the tile was assessed by the panel of evaluators. The amounts of composition diluted to one litre with water were 20, 25 and 50 grams. At each dilution composition D gave less streaking than composition C.

Claims

1. A perfumed aqueous liquid composition comprising a solution of alkali metal hypochlorite, the composition further containing a surfactant mixture comprising (i) an alkane sulphonate of formula R-SO3M in which R
is an alkyl group with 8 to 22 carbon atoms and either (ii) an alkyl ether sulphate of formula R1-(OC2H4)n SO4M in which R1 is an alkyl group with 8 to 20 carbon atoms and n has a value in the range from 0.5 to 12, and/or (iii) soap of formula R2CO2M where R2 is an alkyl or alkenyl group of 7 to 19 carbon atoms, each M denoting a solubilising cation;
characterised in that the composition is a clear liquid solution containing at least 0.1% by weight of perfume, and in that the amounts of the said surfactants, by weight based on the whole composition, are:
i) alkane sulphonate 1 to 10%
ii) alkyl ether sulphate 0 to 3%
iii) soap 0 to 3%
but the total of (ii) and (iii) being 0.1 to 4%, the amount of amine oxide (if any) in the composition being less than half the content of surfactants other than amine oxides.

2. A composition according to Claim 1 in which R1 and R2CO2- each have an average of 10 to 16 carbon atoms.

3. A composition according to Claim 1 or Claim 2 wherein the content of sodium chloride (if any) is not more than half the amount of available chlorine by weight.

4. A composition according to claim 1 or Claim 2 containing, by weight based on the whole composition:

i) alkane sulphonate 1 to 6%
ii) alkyl ether sulphate 0 to 2%
iii) soap 0.2 to 2%
Total of (ii) and (iii) 0.2 to 3%.

5. A composition according to Claim 4 wherein the content of sodium chloride (if any) is not more than half the amount of available chlorine by weight.

6. A composition according to any one of Claims 1 to 5 containing 0.1 to 0.6% by weight perfume.

7. A composition according to any one of the preceding claims wherein the content of hydrotrope (if any) is less than half the content of surfactants other than amine oxides.