Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – Liquid composition
Reexamination Certificate
1999-08-09
2001-06-05
Ogden, Necholus (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
Liquid composition
C510S125000, C510S127000, C510S427000, C510S428000, C510S432000, C510S502000
Reexamination Certificate
active
06242412
ABSTRACT:
The present invention relates to a liquid detergent composition and, in particular, a mild detergent composition suitable for cleansing the skin and hair and comprising a synthetic anionic surfactant, an amphoteric surfactant and relatively high levels of polyethylene glycol (i.e., about 10% and above).
Traditionally, soap has been an essential component of personal washing compositions both in the solid and liquid form. However, whilst soap based formulations deliver an abundance of lather, soap is considered to be a harsh surfactant which is likely to damage the stratum comeum, i.e., the outer layer of the skin, washed with it. Consequently, there has been a move to replace soap, at least partially, in such formulations with synthetic surfactants such as sodium lauryl ether sulphate, commonly referred to as SLES. Formulations based on such anionic surfactants alone tend to produce an abundance of lather during use but the lather is perceived as being of poor quality by the consumer due to its thinness and lack of creaminess. To improve the quality of the lather amphoteric surfactants, and in particular, betaines are commonly added to such compositions as a co-surfactant. Since betaines are mild, their incorporation also leads to improvements in the mildness of the overall composition. As the ratio of amphoteric surfactant to synthetic anionic surfactant is increased so the composition becomes milder however, this is at the expense of the quantity of lather produced during its use.
Attempts to improve lather by increasing the total level of active detergent components in the composition have been unsuccessful. Hence, there has been little exploitation of very mild detergent compositions, particularly in those countries where the quantity and quality of the lather is perceived important by users of such products.
U.S. Pat. No. 5,580,848 to Drapier teaches light duty liquid compositions which impart mildness to skin in form of microemulsions designed especially for cleaning hard surfaces. The composition discloses OAN microemulsions containing one or more surfactant, water immiscible solvent and “cosurfactant” stabilizer. Compositions are said to desire reduced interfacial tension.
Although the cosurfactant stabilizer may be polyethylene glycol, this is one of many, many such cosurfactants which may be used. Where used in one example only, it is used at only 2% levels and there is clearly no teaching or suggestion of using levels of at least 10%, or that such levels provide enhanced mildness.
Indeed, higher levels would be undesirable because foaming is not a desirable attribute in soap compositions.
U.S. Pat. No. 5,604,195 to Misselyn et al. is an all purpose liquids where again PEG may be used as soluble cosurfactant. Again, because such compositions seek to minimize lather, high levels of PEG would not be desired. Further, there is no teaching or suggestion that such high levels minimize harshness in PW compositions.
U.S. Pat. No. 5,696,073 to Jakubicki et al. teaches light duty liquid where low MW PEG may be used in amounts up to 12% as solubilizing agent. There is no recognition that, only at levels of 10% and above (criticality) will compositions (e.g., those of the subject invention) have enhanced mildness.
BRIEF DESCRIPTION OF THE INVENTION
We have now found that, for formulations comprising a synthetic anionic surfactant and an amphoteric surfactant in a weight ratio in the range 4:1 to 0.1:1, both mildness and lather can be boosted by the addition of minimum required of specified polyethylene glycols.
Polyethyleneglycol has been suggested as an optional component for detergent compositions comprising a mixture of anionic and amphoteric surfactants and an insoluble nonionic oil such as in WO 93/19149. However, in this reference it is mentioned as one of a large group of nonocclusive moisturizers. There is no suggestion that it can be used as a lather booster or that it enhances mildness when used at certain levels.
DETAILED DESCRIPTION OF THE INVENTION
The invention provides an aqueous liquid detergent composition comprising a synthetic anionic surfactant and an amphoteric surfactant in a weight ratio in the range 4:1 to 0.1:1 and a polyethylene glycol having a molecular weight of not more than 100,000. Such compositions have both enhanced lather and enhanced mildness.
Anionic Surfactant
Synthetic anionic surfactants are an essential component of the invention as claimed. Suitable materials include fatty acyl isethionates of formula:
RCO
2
CH
2
CH
2
SO
3
M
where R is an alkyl or alkenyl group of 7 to 21 carbon atoms and M is a solubilizing cation such as sodium, potassium, ammonium or substituted ammonium. Preferably at least three quarters of the RCO groups have 12 to 18 carbon atoms and may be derived from coconut, palm or a coconut/palm blend.
Other possible anionic detergents include alkyl glyceryl ether sulphate, sulphosuccinates, taurates, sarcosinates, sulphoacetates, alkyl phosphate, alkyl phosphate esters and acyl lactylate, alkyl glutamates and mixtures thereof.
Sulphosuccinates may be monoalkyl sulphosuccinates having the formula:
R
5
O
2
CCH
2
CH(SO
3
M)CO
2
M;
and amido-MEA sulphosuccinates of the formula:
R
5
CONHCH
2
CH
2
O
2
CCH
2
CH(SO
3
M)CO
2
M;
wherein R
5
ranges from C
9
-C
20
alkyl, preferably C
12
-C
15
alkyl and M is a solubilizing cation.
Sarcosinates are generally indicated by the formula:
R
5
CON(CH
3
)CH
2
CO
2
M,
wherein R
5
ranges from C
9
-C
20
alkyl, preferably C
12
-C
15
alkyl and M is a solubilizing cation.
Taurates are generally identified by the formula:
R
5
CONR
6
CH
2
CH
2
SO
3
M,
wherein R
5
ranges from C
9
-C
20
alkyl, preferably C
12
-C
15
alkyl, R
6
ranges from C
1
-C
4
alkyl, and M is a solubilizing cation.
More preferably the anionic surfactant is an alkyl ether sulphate of formula:
R
4
O(CH
2
CH
2
O)
n
SO
3
M
where R
4
is an alkyl group of 8 to 22 carbon atoms, n ranges from 0.5 to 10 especially 1.5 to 8, and M is a solubilizing cation as before, most preferably the anionic surfactant is sodium lauryl ether sulphate.
Amphoteric Surfactant
Suitable amphoteric surfactants are detergents which have an alkyl or alkenyl group of 7 to 18 carbon atoms and comply with an overall structural formula:
where R
1
is alkyl or alkenyl of 7 to 18 carbon atoms R
2
and R
3
are each independently alkyl, hydroxyalkyl or carboxyalkyl of 1 to 3 carbon atoms.
M is2 to 4,
N is 0 or 1,
X is alkylene of 1 to 3 carbon atoms optionally substituted with hydroxyl, and
Y is —CO
2
−
or —SO
3
−
They include simple betaines of formula:
and amido betaines of formula:
where m is 2 or 3.
In both formulae R
1
, R
2
and R
3
are as defined previously. R
1
may, in particular, be a mixture of C
12
and C
14
alkyl groups derived form coconut so that at least half of the groups R
1
have 10 to 14 carbon atoms. R
2
and R
3
are preferably methyl.
A further possibility is a sulphobetaine of formula:
or
wherein m is 2 or 3, or variants of these in which
—(CH
2
)
3
SO
3
−
is replaced by
R
1
, R
2
and R
3
in these formulae are as defined previously. Amido betaines are most preferred.
The total level of anionic and amphoteric surfactant in the composition according to the invention preferably lies within the range 5 to 50 wt. %, most preferably 7 to 35 wt. %.
For optimum mildness, the weight ratio of the anionic surfactant to amphoteric surfactant should lie within the range 4:1 to 0.1:1, preferably 3:1 to 0.5:1, more preferably 2:1 to 0.5:1.
The composition may also contain nonionic surfactants. Suitable nonionic surface active agents include alkyl polysaccharides, lactobionamides, ethylene glycol esters, glycerol monoethers, polyhydroxyamides (glucamide), primary and secondary alcohol ethoxylates, especially the C
8-20
aliphatic alcohols ethoxylated with an average of from 1 to 20 moles of ethylene oxide per mole of alcohol.
Preferably fatty acid soaps are not added to the detergent compositions of the invention. However, if present, they are at a level of not more than 25 wt. % based on the level of synthetic anionic
Chambers John George
Kutsuwa Izumi
Serridge David
Koatz Ronald A.
Ogden Necholus
Unilever Home & Personal Care USA , division of Conopco, Inc.
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