Detergent compositions

Details Detergent compositions Detergent compositions

2002-10-10

2004-03-30

Mruk, Brian P (Department: 1751)

Cleaning compositions for solid surfaces, auxiliary compositions

Cleaning compositions or processes of preparing

For cleaning a specific substrate or removing a specific...

C510S334000, C510S351000, C510S356000, C510S357000, C510S360000, C510S445000, C510S466000, C510S475000, C510S492000, C510S507000, C510S531000, C510S535000

Reexamination Certificate

active

06713442

ABSTRACT:

TECHNICAL FIELD
The present invention relates to built laundry detergent compositions containing anionic sulphonate or sulphate surfactants and a textile softening clay, the compositions exhibiting increased mildness to the skin as well as improved textile softening properties.
BACKGROUND
Heavy duty laundry detergent compositions have for many years contained an anionic sulphonate or sulphate surfactant, for example, linear alkylbenzene sulphonate (LAS) or primary alcohol sulphate (PAS), as the principal detergent-active ingredient. These anionic surfactants are frequently used in conjunction with ethoxylated alcohol nonionic surfactants which give improved detergency on hydrophobic soils. The nonionic surfactants generally have alkyl chain lengths of C
12
-C
18
and degrees of ethoxylation of 1 to 10.
These anionic and anionic
onionic surfactant systems are robust and highly efficient on a wide range of soils and under a wide range of conditions, for example, temperature and water hardness. However, they are not noted for mildness to skin. These materials are designed to interact with fatty materials like body soil and protein residues on soiled laundry, and can therefore interact with the skin to give reactions such as dryness and erythema (redness). The milder surfactants used to formulate products intended for prolonged skin contact, for example, shampoos and shower gels, would not perform adequately in heavy duty laundry detergent compositions because of insufficient interaction with fatty materials occurring as soil.
It has now been surprisingly discovered that the mildness to skin of a laundry detergent composition containing an anionic sulphonate or sulphate detergent and a conventional detergent ethoxylated nonionic surfactant can be significantly improved, without detriment to detergency performance, by the incorporation of a low level of a much more highly ethoxylated nonionic surfactant.
It is also well known to incorporate textile softening clays, for example bentonites, into laundry detergents in order to achieve some softening during the main wash. It is normally necessary to incorporate clays at levels of, for example, 7 to 10 wt %, in order to see a significant benefit. Surprisingly, it has now been found that, when a highly ethoxylated nonionic surfactant is also present, significant softening benefits are observed at lower clay incorporation levels. This is especially surprising because, in the absence of clay, the addition of the highly ethoxylated nonionic surfactant has a negative effect on softening.
PRIOR ART
GB 2 020 688 (Unilever) discloses a high suds washing powder comprising an active blend of an anionic surfactant and a nonionic surfactant. Only one type of nonionic surfactant in combination with anionic surfactant is disclosed.
U.S. Pat. No. 4,954,292 (Lever Brothers) discloses a detergent composition which comprises anionic surfactant, PVP and a blend of nonionic surfactants. An example is given which discloses, inter alia, Synperonic A3 and A7 together.
WO 94 16052A (Unilever) discloses high bulk density particulate laundry detergent compositions containing low levels (typically below 1 wt %) of a highly ethoxylated long chain alcohol, for example tallow alcohol 80EO, the benefit being improved dissolution.
EP 293 139A (Procter & Gamble) discloses detergent compositions enclosed in two-compartment sachets, the compositions exemplified containing low levels (0.2-0.8 wt %) of tallow alcohol 25EO.
WO 93 02176A (Henkel) discloses the use of highly ethoxylated aliphatic alcohols as “structure breakers” in high bulk density laundry detergent powders containing conventional ethoxylated alcohol nonionic surfactants.
WO 00 08129A (Unilever) discloses mild Particulate laundry detergent compositions based on high-foaming anionic surfactant (for example linear alkylbenzene sulphonate) plus one or more milder cosurfactants, for example, amine oxide or cocoamidopropyl betaine.
Particulate laundry detergent compositions containing textile softening clays are widely disclosed, for example, in EP 299 575B (Procter & Gamble), EP 313 146B (Procter & Gamble), EP 383 828B (Novo Nordisk and Procter & Gamble), EP 495 258A (Procter & Gamble), EP 753 567A (Procter & Gamble) and EP 582 478B (Colgate-Palmolive).
DEFINITION OF THE INVENTION
The present invention provides a built particulate laundry detergent composition comprising
(i) from 5 to 25 wt % of an anionic sulphonate or sulphate surfactant,
(ii) from 1 to 10 wt % of an ethoxylated alcohol nonionic surfactant having an alkyl chain length of from C
8
to C
18
and an average degree of ethoxylation of from 3 to 10,
(iii) from 0.5 to 5 wt % preferably from 1 to 3 wt % of a highly ethoxylated alcohol nonionic surfactant having an average degree of ethoxylation of from 15 to 40,
(iv) from 0.5 to 5 wt % of a textile softening clay,
(v) from 10 to 80 wt % of detergency builder and
(vi) optionally other detergent ingredients to 100 wt %.
The present invention further provides the use of the combination of a highly ethoxylated alcohol nonionic surfactant having an average degree of ethoxylation of from 15 to 40 in an amount of from 0.5 to 5 wt % and a textile softening clay in an amount of from 0.5 to 5 wt % to increase the mildness to skin and textile softening effect of a built particulate laundry detergent composition containing an anionic sulphonate or sulphate detergent.
DETAILED DESCRIPTION OF THE INVENTION
Detergent compositions of the invention contain a conventional anionic sulphonate or sulphate surfactant and a conventional nonionic surfactant, and also contain as essential ingredients a low level of a highly ethoxylated nonionic surfactant (iii) which is an aliphatic alcohol having an average degree of ethoxylation of from 15 to 40, and a low level of a textile softening clay (iv).
The invention is based first on the observation that use or a highly ethoxylated nonionic surfactant at low levels to supplement or replace part of a conventional anionic
onionic surfactant system results in a measurable increase in mildness to skin.
It is well known and intuitively obvious that the mildness to skin of a formulation can be increased simply by reducing the amount of surfactant. However, cleaning efficiency is then reduced. Surprisingly, it has now been found that addition of low levels of highly ethoxylated nonionic surfactant will increase mildness even when the total surfactant level is kept constant, i.e. the high ethoxylate replaces a small proportion of the other surfactants. For example, in a formulation containing 15 wt % surfactant (LAS and ethoxylated nonionic) replacement of as little as 5 wt % of that surfactant is beneficial with respect to mildness, and there is no loss of cleaning efficiency. It is surprising that such a small addition has a significant effect. The effect on mildness is significantly greater than that of an equal amount of alkyl ether sulphate or cocoamidopropyl betaine, both of which are known from the prior art as supplements to increase mildness.
However, the incorporation of highly ethoxylated nonionic surfactant was found to have a negative effect on the softness of washed fabrics. To counteract that, it was proposed to add a textile softening clay as known from the prior art. Surprisingly, it was found that much lower levels of clay than expected were effective, not only to cancel out the negative effect on fabric softness of the highly ethoxylated nonionic surfactant but actually to give better softening than if the highly ethoxylated nonionic surfactant were absent.
According to an especially preferred embodiment of the invention, the skin-mild detergent compositions of the invention are free of enzymes, since enzymes can also cause skin irritation to sensitive individuals. However, enzymatic compositions are also within the scope of the invention.
The Anionic Sulphonate or Sulphate Surfactant (i)
Anionic sulphonate and sulphate surfactants are well-known to those skilled in the art. Many suitable detergent-active compounds are available and are fully described in the literat

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