Cleaning compositions for solid surfaces – auxiliary compositions – Cleaning compositions or processes of preparing – For cleaning a specific substrate or removing a specific...
Reexamination Certificate
2001-12-19
2004-04-06
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...
C510S351000, C510S352000, C510S357000, C510S359000, C510S361000, C510S504000, C510S492000
Reexamination Certificate
active
06716807
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 −1.75wt %) and in one case, a low amount of zeolite (1.5wt %) 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
A detergent composition comprising:
(a) more than 10 wt % of a calcium-tolerant non-soap anionic surfactant system;
(b) from 0.1% to 10%, preferably from 0.5% to 10%, more preferably from 1% to 10% by weight of a strong builder system selected from phosphate builders and aluminosilicate builders and mixtures thereof; and
(c) the balance, if any, being other detergent ingredients wherein said composition comprises less than 35wt %, preferably less than 25 wt %, more preferably less than 15 wt % of non-functional non-alkaline water soluble inorganic salt.
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
The composition of the invention contains more than 10 wt % of calcium tolerant anionic surfactant. 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 65 wt %, more preferably from 20 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.
The preferred non-soap calcium tolerant anionic surfactant for use in the compositions of the present invention is alpha-olefin sulphonate.
Advantageously alkyl ether sulphate (another non-soap calcium tolerant material) may be present, preferably as a co-surfactant with the alpha-olefin sulphonate, in an amount less that that of the latter.
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 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.
The Strong Builder System
The strong builder system is selected from phosphate builders, aluminosilicate builders and mixtures thereof. The total amount of this strong builder system is from 0.1% to 10%, preferably from 0.5% to 10%, more preferably from 1% to 10% by weight of the composition. However, one or more weak builders such as calcite/carbonate, citrate or polymer builders may also be present.
The phosphate builder (if present) may for example be selected from alkali metal, preferably sodium, pyrophosphate, orthophosphate and tripolyphosphate, and mixtures thereof.
The aluminosilicate may be, for example, selected from one or more crystalline and amorphous aluminosilicates, for example, zeolites as disclosed in GB 1 473 201 (Henkel), amorphous aluminosilicates as disclosed in GB 1 473 202 (Henkel) and mixed crystalline/amorphous aluminosilicates as disclosed in GB 1 470 250 (Procter & Gamble); and layered silicates as disclosed in EP 164 514B (Hoechst
The alkali metal aluminosilicate may be either crystalline or amorphous or mixtures thereof, having the general formula: 0.8-1.5 Na
2
O. Al
2
O
3
. 0.8-6 SiO
2
.
These materials contain some bound water and are required to have a calcium ion exchange capacity of at least 50 mg CaO/g. The preferred sodium aluminosilicates cont
Metcalfe Kenneth
Van der Hoeven Philippus Cornelis
Delcotto Gregory
Mitelman Rimma
Unilever Home & Personal Care USA , division of Conopco, Inc.
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