Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2001-12-11
2004-04-13
Boyer, Charles (Department: 1751)
Cleaning compositions for solid surfaces, auxiliary compositions
Cleaning compositions or processes of preparing
For cleaning a specific substrate or removing a specific...
C510S276000, C510S356000, C510S357000, C510S421000, C510S426000, C510S445000
Reexamination Certificate
active
06720298
ABSTRACT:
TECHNICAL FIELD
The present invention relates to laundry detergent compositions containing a combination of anionic and specified nonionic surfactants giving improved oily soil detergency, especially under hard water conditions.
BACKGROUND
Heavy duty laundry detergent compositions have for many years contained anionic sulphonate or sulphate surfactant, for example, linear alkylbenzene sulphonate (LAS), together with ethoxylated nonionic surfactants. Examples abound in the published literature.
The preferred ethoxylated alcohol nonionic surfactants giving an optimum balance of properties have generally been those having an alkyl chain length of C
12
-C
15
and an average degree of ethoxylation of 1 to 10, preferably 3 to 7, more preferably about 5.
Longer-chain alcohols having a higher degree of ethoxylation, for example, tallow alcohol (C
18
) 11EO, have also been used.
These relatively hydrophobic materials of low HLB value are generally liquids at ambient temperature and exhibit excellent oily soil removal.
Longer-chain alcohols having higher degrees of ethoxylation, for example, tallow (C
18
) alcohol 25EO and 50EO, are solids at ambient temperature and are used as slowly dissolving coating materials, for example, for enzyme or antifoam granules.
It has now surprisingly been found that ethoxylated alcohols combining a shorter alkyl chain length and a higher degree of ethoxylation, when used in minor amounts together with an anionic sulphonate or sulphate surfactant, can give enhanced oily soil removal. The benefit is especially great under hard water conditions.
PRIOR ART
WO 94 16052A (Unilever) discloses high bulk density laundry powders based on LAS and conventional nonionic surfactants, and containing small amounts of very highly ethoxylated alcohols, eg tallow alcohol 80EO, as a dissolution aid.
EP 293 139A (Procter & Gamble) discloses twin-compartment sachets containing detergent powders. Some powders contain very small amounts of tallow alcohol 25EO.
WO 93 02176A (Henkel) discloses the use of highly ethoxylated aliphatic alcohols as “structure breakers” in high bulk density powders containing conventional nonionic surfactants.
U.S. Pat. No. 4,294,711 (Procter & Gamble) discloses a textile softening heavy duty detergent composition containing 1 wt % of tallow alcohol 80EO.
WO 92 18594A (Procter & Gamble) discloses builder granules of layered silicate coated with tallow alcohol 50EO.
EP 142 910A and EP 495 345A (Procter & Gamble) disclose antifoam granules containing highly ethoxylated alcohols.
WO 93 19148A (Procter & Gamble) discloses liquid hard surface cleaning compositions containing highly ethoxylated nonionic surfactants optionally plus anionic surfactant.
GB 2 279 660A (Procter & Gamble) discloses a liquid laundry detergent composition containing a solid water-insoluble organic peroxyacid bleach and a C
8
-C
20
2-20EO ethoxylated alcohol nonionic surfactant, but only lower ethoxylates (9EO and below) are specifically disclosed.
WO 98 18892A (Du Pont) discloses a carpet cleaning formulation containing a C
10
-C
16
ethoxylated alcohol of HLB value 10.5-15.
DEFINITION OF THE INVENTION
The present invention provides a built laundry detergent composition comprising
(i) from 5 to 40 wt %, preferably from 7 to 30 wt %, of surfactant consisting essentially of:
(i)(a) from 60 to 99 wt %, preferably from 80 to 95 wt %, based on the surfactant (i), of anionic sulphonate or sulphate surfactant,
(i)(b) from 1 to 40 wt %, preferably from 5 to 20 wt %, based on the surfactant (i), of an ethoxylated alcohol nonionic surfactant of the formula
R—(—O—CH
2
—CH
2
)
n
—OH
wherein R is a hydrocarbyl chain having from 8 to 16 carbon atoms, and the average degree of ethoxylation n is from 20 to 50,
(ii) from 10 to 80 wt % of detergency builder,
(iii) optionally other detergent ingredients to 100 wt %.
The invention also provides a process for laundering textile fabrics by machine or hand, which includes the step of immersing the fabrics in a wash liquor comprising water in which a laundry detergent composition as defined in the previous paragraph is dissolved or dispersed, wherein the water has a hardness of at least 20 degrees (French).
The invention further provides the use of a surfactant (i) consisting essentially of
(i)(a) from 60 to 99 wt %, preferably from 80 to 95 wt %, based on the surfactant (i), of anionic sulphonate or sulphate surfactant,
(i)(b) from 1 to 40 wt %, preferably from 5 to 20 wt %, based on the surfactant (i), of an ethoxylated alcohol nonionic surfactant of the formula
R—(—O—CH
2
—CH
2
)
n
—OH
wherein R is a hydrocarbyl chain having from 8 to 16 carbon atoms, and the average degree of ethoxylation n is from 20 to 50,
in a laundry detergent composition in an amount of from 5 to 40 wt %, to improve the oily soil detergency of the composition especially in water having a hardness of at least 20 degrees (French).
DETAILED DESCRIPTION OF THE INVENTION
Detergent compositions of the invention provide increased detergency on oily soils, especially under hard water conditions, for example, using water of a hardness of at least 20 degrees (French). The benefit is especially apparent at very high water hardnesses, for example, more than 30 degrees (French).
The Surfactant Combination (i)
The detergent compositions of the invention contain a combination of an anionic sulphonate or sulphate surfactant, and a defined nonionic surfactant. The total amount of the two surfactants is from 5 to 40 wt %, preferably from 7 to 30 wt %.
The surfactant combination consists essentially of from 60 to 99 wt %, preferably from 80 to 95 wt % and more preferably from 85 to 95 wt %, of anionic sulphonate or sulphate detergent, and from 1 to 40 wt %, preferably from 5 to 20 wt % and more preferably from 5 to 15 wt %, of the defined nonionic surfactant.
In the compositions of the invention, the weight ratio of anionic surfactant (i)(a) to nonionic surfactant (i)(b) is from 2:1 to 25:1, preferably from 3:1 to 20:1. Especially good results are obtained when the ratio is from 5:1 to 10:1.
The whole product (composition) preferably contains:
(i)(a) from 3 to 30 wt %, preferably from 5 to 25 wt %, of the anionic sulphonate or sulphate surfactant, and
(i)(b) from 0.5 to 10 wt %, preferably from 1 to 5 wt %, of the nonionic surfactant (i)(b).
Optionally minor, non-interfering amounts of other surfactants may also be present. Preferably, however, the composition is free from nonionic surfactants other than the defined nonionic surfactant (i)(b).
More preferably the composition is substantially free of other non-soap surfactants.
Optionally soap may also be present, for example, in an amount of from 1 to 5 wt %.
The Anionic Surfactant (i)(a)
The anionic surfactant is a sulphonate or sulphate anionic surfactant.
Anionic surfactants are well-known to those skilled in the art. Many suitable detergent-active compounds are available and are fully described in the literature, for example, in “Surface-Active Agents and Detergents”, Volumes I and II, by Schwartz, Perry and Berch.
Examples include alkylbenzene sulphonates, primary and secondary alkylsulphates, particularly C
8
-C
15
primary alkyl sulphates; alkyl ether sulphates; olefin sulphonates; alkyl xylene sulphonates; dialkyl sulphosuccinates; and fatty acid ester sulphonates. Sodium salts are generally preferred.
Preferably the anionic surfactant is linear alkylbenzene sulphonate or primary alcohol sulphate. More preferably the anionic surfactant is linear alkylbenzene sulphonate.
The Ethoxylated Nonionic Surfactant (i)(b)
The nonionic surfactant is an ethoxylated aliphatic alcohol of the formula
R—(—O—CH
2
—CH
2
)
n
—OH
wherein R is a hydrocarbyl chain having from 8 to 16 carbon atoms, and the average degree of ethoxylation n is from 20 to 50.
The hydrocarbyl chain, which is preferably saturated, preferably contains from 10 to 16 carbon atoms, more preferably from 12 to 15 carbon atoms. In commercial materials containing a spread of chain lengths, these figures represent an average.
The alcohol may be derived from natural or synthetic feedstock.
Blything Sandra Ann
Singh Amrat Paul
Titley Thelma Christine
Boyer Charles
Mitelman Rimma
Unilever Home & Personal Care USA , division of Conopco, Inc.
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