Detergent compositions

Details Detergent compositions Detergent compositions

2001-12-19

2004-05-04

Delcotto, Gregory (Department: 1751)

Cleaning compositions for solid surfaces, auxiliary compositions

Cleaning compositions or processes of preparing

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

C510S350000, C510S351000, C510S352000, C510S357000, C510S359000, C510S361000, C510S504000

Reexamination Certificate

active

06730649

ABSTRACT:

TECHNICAL FIELD
The present invention relates to a laundry detergent composition, which may, for example, be formulated as a particulate, tablet or liquid composition.
BACKGROUND TO THE INVENTION
Conventional laundry detergent powders intended for the handwash contain a substantial level of anionic surfactant, most usually alkylbenzene sulphonate. Anionic surfactants are ideally suited to the handwash because they combine excellent detergency on a wide range of soils with high foaming.
However, event at high levels of anionic surfactant, for handwashing, the oily soil removal performance of such products is in need of improvement.
GB-A-1 570 128 discloses detergent compositions comprising from 4 to 40 wt % of a magnesium-insensitive surfactant (for example, alkyl ether sulphate, ethoxylated nonionic surfactant, amine oxide), from 13 to 40 wt % of sodium silicate, and from 5 to 50 wt % of a magnesium-selective detergency builder (for example, zeolite, sodium citrate, nitrilotriacetate, or calcite/carbonate).
JP-A-09 087 690 discloses a high-bulk-density granular detergent composition for machine wash use, containing anionic (5 to 40 wt %), plus ethoxylated nonionic surfactant (1 to 15 wt %), zeolite (10 to 40 wt %), and crystalline and amorphous sodium silicates (0.5 to 10 wt %). The anionic surfactant optionally contains alpha-olefin sulphonate (up to 10 wt % in the examples).
WO-A-97/43366 relates to detergent composition comprising from 0.5% to 60% by weight an anionic surfactant and from 0.01% to 30% by weight of a cationic surfactant. In the exemplified compositions in this document, the level of anionic surfactant is typically from about 10% to 15% by weight of the composition and the amount of cationic surfactant is from about 1% to 4% by weight. In some examples, the anionic surfactant component contains small amounts of an alkyl ether sulphate surfactant, typically at from 0.76% to 2.5% by weight of the total composition.
Compositions with small amounts of alkyl ether sulphate anionic surfactant (up to-1.75 wt %) and in one case, a low amount of zeolite (1.5 wt %) are disclosed in WO-A-98/01521. However, these compositions are spray-dried and therefore have high amounts of sodium sulphate which is a non-alkaline non-functional water-soluble salt (electrolyte).
Other spray-dried compositions with high levels of sodium sulphate and containing alpha-olefin sulphate anionic surfactant, together with 12 or 15 wt % zeolite builder are disclosed in JP-A-62 218499.
WO-A-00/40682 discloses compositions comprising more than 40% of an anionic surfactant system at least some comprising a calcium tolerant surfactant such as an alpha-olefin sulphonate or alkyl ether sulphate. The examples with calcium tolerant surfactant either contain no phosphate or aluminosilicate builder or else a very high level of phosphate.
Our UK Patent Application No. 9925961.6 also discloses compositions with 5-30 wt % of alpha-olefin sulphonate. These are all based on a calcite/carbonate builder system.
Other compositions containing calcium tolerant surfactants are disclosed in U.S. Pat. No. 6,010,996, GB-A-2 309 706, U.S. Pat. No. 5,415,812, U.S. Pat. No. 4,265,777 and U.S. Pat. No. 4,970,017.
There remains a need, fulfilled by the present invention, for compositions which contain a strong builder, namely a phosphate or aluminosilicate builder, but at lower levels, yet which are still robust across a wide range of water hardness.
DEFINITION OF THE INVENTION
The present invention provides a detergent composition comprising:
(a) at least 5 wt % of a calcium-tolerant non-soap anionic surfactant system which comprises an alpha-olefin sulphonate;
(b) at least 0.1 wt % of a cationic surfactant system in a weight ratio of (a):(b) of from 17:3 to 9:10, preferably from 3:1 to 1:1;and
(c) the balance, if any, being other detergent ingredients.
DETAILED DESCRIPTION OF THE INVENTION
The composition of the invention is based on mixed calcium tolerant anionic surfactant systems, plus moderate amounts of phosphate and/or aluminosilicate builder.
The Anionic Surfactant System (a)
The composition of the invention contains at least 5 wt % of calcium tolerant anionic surfactant comprising an alpha-olefin sulphonate. Typically, the upper level of this calcium tolerant anionic surfactant system will be 75 wt %. However, preferably, the anionic surfactant system is present at from 15 wt % to 70 wt %, more preferably from 2 wt % to 60 wt %, especially from 30 wt % to 50 wt % based on the weight of the total composition.
The calcium ion stability of anionic surfactants can be measured by the modified Hart method (Witkes, et al. J. Ind. Encl. Chem. 29, 1234-1239 (1937)), carried in microtiter plates. The surfactant solution is titrated with a calcium ion solution. The onset of turbidity indicates the start of formation of insoluble calcium precipitates after a minute of shaking at room temperature.
As referred to herein, a “calcium tolerant” surfactant is one that does not precipitate at a surfactant concentration of 0.4 g/L (and at a ionic strength of a 0.040 M 1:1 salt solution at) with a calcium concentration up to 20° FH (French hardness degrees), i.e. 200 ppm calcium.
An essential non-soap calcium tolerant anionic surfactant for use in the compositions of the present invention is alpha-olefin sulphonate.
Advantageously one or more other calcium tolerant anionic surfactant alkyl ether sulphate (another non-soap calcium tolerant material) may be present, in an amount less that that of the alpha-olefin sulphonate.
A preferred surfactant system comprises alpha-olefin sulphonate and alkyl ether sulphate in a weight ratio of from 5:1 to 15:1.
Other calcium-tolerant anionic surfactants that may be used in addition to the alpha-olefin sulphonate acid alone or in combination with these or other calcium-tolerant anionics are alkyl ethoxy carboxylate surfactants (for example, Neodox (Trade Mark) ex Shell), fatty acid ester sulphonates (for example, FAES MC-48 and ML-40 ex Stepan), alkyl xylene sulphonates, dialkyl sulphosuccinates, fatty acid ester sulphonates, alkyl amide sulphates, sorpholipids, alkyl glycoside sulphates and alkali metal (e.g. sodium ) salts of saturated or unsaturated fatty acids.
More than one other anionic surfactants may also be present. These may for example be selected from one or more of alkylbenzene sulphonates, primary and secondary alkyl sulphates.
When it is desired to avoid the calcium intolerance of alkylbenzene sulphonate surfactant altogether, then the anionic surfactant system may comprise (preferably at a level of 70 wt % or more of the total anionic surfactant) or consist only of one or more calcium-tolerant non-soap anionic surfactants.
Cationic Surfactant Systems
The compositions of the present invention contain at least 0.1% by weight of the cationic surfactant system. Typically, the cationic surfactant system may be present at up to 15 wt % of the total composition. However, it preferably is present at from 0.5 wt % to 5 wt % at the composition.
Preferred cationic surfactant types include those having the formula:
R1R2R3R4N+X—
wherein
R1=is a hydrophobic group (preferably) C12-14 alkyl, or derived from Coco;
R2, R3 or R4 are independently hydroxyethyl, hydroxypropyl or C1-4 alkyl (e.g. Me, Et) group;
X—is a solubilising cation, preferably Cl—, Br—or MeSO4
−
Specific examples are:
R1
R2, R3, R4
(i) alkyl hydroxyethyl
C12
2 methyl, 1 hydroxyethyl
dimethylammonium chloride
HoeS3996 (now sold as
Praepagen HY) (ex Clariant,
prev. Hoechst)
(ii) Alkyl dihydroxyethyl
C12
1 methyl, 2-hydroxyethyl
methylammonium chloride
Bis-AQA types (ex Clariant)
e.g. Ethoquad C/12 type
(AKZO-Nobel)
(iii) alkyl trimethyl
<C16 pref. C12
3 methyl
ammonium chloride
Arquad types (eg. Arquad
C33W)
The definition of cationic surfactants also include QMEA (quaternised monoethanolamine) or QTEA (quaternised triethanolamine). Quaternisation can arise as the result of neutralisation in situ of MEA or TEA by a surfactant acid (i.e. LAS acid, fatty acid, paraffin sulphonic acid=SAS acid, etc):
RI
R2, R

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