Methods and compositions

Abstract

A method of laundering articles, the method comprising combining a detergent composition and water to provide a detergent solution, wherein the detergent composition comprises a surfactant system containing a betaine, then introducing into a washing machine basket the detergent solution so as to dampen articles in the basket; and then waiting for a duration of time during which no water or further detergent solution is added to the basket containing the dampened articles.

Claims

1. A method of laundering articles comprising: combining a detergent composition and water to provide a detergent solution, wherein the detergent composition comprises 10% of a surfactant system containing a betaine; introducing into a washing machine basket the detergent solution so as to dampen articles in the basket; and waiting for a duration of time during which no water or further detergent solution is added to the basket containing the dampened articles; wherein the surfactant system comprises a coactive and at least one surfactant; wherein the coactive is cocamidopropyl betaine (CAP-B) and the other surfactants in the surfactant system comprise linear alkylbenzenesulfonates (LAS) and alkyl ether sulfates (AES) in a ratio of from 1:3 to 7:3 LAS:AES; and wherein the cocamidopropyl betaine accounts for 20 wt % of the surfactant content of the composition.

2. The method of claim 1, wherein the volume of detergent solution is 750 ml or less per kg of articles to be laundered.

3. The method of claim 1, wherein the detergent is a liquid detergent product.

4. The method of claim 1, wherein the method further comprises a washing step after the waiting step, the washing step comprising adding water to a drum and agitating the articles, wherein no detergent is added during the washing step.

5. The method of claim 4 wherein the washing step does not include heating.

6. The method of claim 2, wherein the volume of detergent solution is 500 ml or less per kg of articles to be laundered.

7. The method of claim 6, wherein the volume of detergent solution is 150 ml or less per kg of articles to be laundered.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a schematic view of a washing machine configuration according to the disclosure.

DETAILED DESCRIPTION

(2) The invention will be described with reference to FIG. 1, which shows schematically one how the basket, drum and chamber of a washing machine can be configured to carry out the method of the invention. It will appreciated that this is provided by way of illustration and not by way of limitation. A horizontal axis machine is shown. Naturally, the methods of the invention may also use vertical axis machines.

(3) The washing machine has a basket 1. Prior to washing, articles 2 are placed in this basket. For ease of illustration, a small volume of articles is shown. In a usual wash load, the volume within the basket may be much greater. The basket 1 is housed within a drum 3. There is a void between the basket and outer circumference of the drum. This is labelled “V”. The void V is often referred to as the “outer drum”. Conventional horizontal axis washing machines have this arrangement. During a normal wash cycle, the wash liquors are present not only in the drum, but also at the bottom of this void. Therefore, during a normal fill from the bottom of the drum upwards, a significant volume of wash liquor enters the drum before beginning to wet the cloths. The basket 1 has holes in its wall, so that excess liquid passes through the wall into the outer drum, for example, during spinning. In vertical axis machines, the void surrounds the basket circumference in the horizontal plane.

(4) During spinning, the drum may be drained, for example, through opening a drain 4. Excess liquid is released from the clothes owing to centrifugal forces. Often, very high rotation speeds are used to remove water, for example 1,000-1,600 rpm.

(5) The machines of the invention have an introducing means 5 for introducing the detergent solution 6 into the basket. As described above, the detergent solution is introduced as a spray or mist, so the introducing means is suitably a nozzle. As is evident from the FIGURE and discussion herein, the detergent solution is applied to the articles without the need to first fill the bottom of the void of the drum.

(6) The detergent solution is prepared in a chamber 7. The chamber is fluidically connected to the introducing mean 5 by a tube 8. As can be seen from the FIGURE, the detergent solution prepared in the chamber passes to the introducing means 5 without first contacting the articles.

(7) In other words, the detergent solution is typically sprayed onto dry articles. A value 9 may be provided to control flow from the chamber to the basket. In some embodiments, the detergent solution is heated. Accordingly, the chamber 7 may comprise or be in thermal contact with a heating means 10. Alternatively or additionally, tube 8 may comprise a heating means such as an in-flow heater.

(8) Chamber 7 comprises an inlet for water 11. Via this inlet, water is introduced to make the detergent solution. Detergent product may be added via an inlet 12. This may simply be to top of a detergent drawer, into which the user pours detergent, or may fluidically link to such a drawer or other detergent reservoir. Inlet 11 and/or inlet 12 may comprise metering means (not shown) to control the amount of detergent and/or water added. This may be determined by the machine performing a weighing step, as described herein.

Definitions

(9) Articles

(10) As used herein, this term refers to fabric items that are laundered, for example, in the machines and methods described herein. Articles may be clothing, bedding, curtains, or any other fabric items.

(11) Dampen

(12) In the power treatment step, the articles are dampened. As used herein, this term means that detergent solution is contacted with the articles so as to adsorp onto the surface of the articles and to at absorb into the fibres of the articles. Individual articles, or indeed portions of articles, may be saturated, but the amount of solution during the power treatment step is not intended to soak the articles in the conventional sense. In other words, it is not intended that there is a significant volume of free solution in the basket. As a result, comparatively little, if any, solution will be lost to the outer drum during the power treatment, even if the drum is rotated to provide agitation.

(13) Detergent

(14) Detergent and detergent product as used herein refer to a laundry formulation comprising a detergent. Suitable detergent products are known in the art. Typically, they contain surfactants and builders. They may or may not contain enzymes. Other ingredients may include alkalis, antiredeposition agents, bleaches, anti-microbial agents, fabric softeners, fragrances, optical brighteners, preservatives, hydrotopes (in the case of liquid products), processing aids, foam boosters and regulators. The detergent products may be powders or liquids.

(15) The detergent product comprises a surfactant system. Suitably, the term surfactant system refers to all of the surfactant present in the detergent product.

(16) The surfactant system may account for 0.5-50 wt % of the detergent product. Preferably, the surfactant system accounts for 0.5-25 wt % of the detergent product, for example 1-15 wt. In some cases, the amount is 8-12 wt %, such as around 10 wt %.

(17) The surfactant system comprises a coactive and one or more surfactants. It will be appreciated that the coactive is also a surfactant.

(18) A preferred coactive is cocamidopropyl betaine (CAP-B). CAP-B is derived from coconut oil and dimethylaminopropylamine. It may be provided as a viscous pale yellow solution.

(19) Suitably, the coactive accounts for at least 5 wt % of the surfactant system, preferably at least 10 wt %, more preferably at least 15 wt %. In a preferred embodiment, the coactive accounts for around 20% of the surfactant system.

(20) In other words, the detergent product may comprise 2 wt % coactive and 8 wt % other surfactants.

(21) Preferably, the other surfactants comprise linear alkylbenzenesulfonates (LAS) and alkyl ether sulfates (AES). In a preferred embodiment, the surfactant system comprises coactive and LAS and AES in a ratio of from 2:8 to about 8:2 LAS:AES. A suitable AES is sodium lauryl ether sulfate (SLES). In some embodiments, no further surfactants are present in the surfactant system. In other embodiments, non-ionic surfactants may also be present.

(22) In some embodiments, the detergent product contains a builder. In some embodiments, the detergent product contains an enzyme.

(23) Detergent Solution

(24) Detergent solution, as used herein, refers to the liquid applied to the articles in the power treatment step. The detergent solution is obtained by mixing detergent product with water in the chamber. Preferably, the mixture is homogeneous, although it will be appreciated that some detergent products may not completely dissolve, leading to some turbidity in the detergent solution.

(25) Direct Application

(26) This refers to application of a product by a consumer, usually in neat (i.e. not diluted) form, to a stain prior to washing. The direct application may use a product designed for such purposes (for example, a stain removal spray), or may use a liquid detergent designed for use in a machine laundry cycle. Direction application may be abbreviated herein to DA.

(27) Dilution Factor

(28) This refers to parts (by volume) of water to parts (by volume) product. For example, a dilution factor of 10 refers to 1 part product to 10 parts water (for example, 10 mL liquid product and 100 mL, 1 part powder detergent to 10 part water).

(29) Wash Program

(30) A washing machine typically has one or more programs which the user selects to suit the articles to be laundered and the degree of soiling. Each program is a sequence of stages with varied conditions (duration, water/solution volume, speed, temperature). As used herein, the word cycle refers to an individual stage and the word program means a combination of those stages.

(31) Wash Cycle

(32) Also called a washing step, this is a wash cycle in which articles are agitated in an excess of detergent solution to clean them.

(33) Typically, the cycles of a wash program include: 1. a wash cycle (in which the drum is filled to a certain level and the articles agitated in the solution, then the solution drained); spinning may be used to aid solution removal; 2. a rinse phase (in which the drum is filled with water to a certain level and the articles agitated in the water, then the water drained); spinning may be used to aid solution removal; 3. a spin cycle, in which the basket is spun rapidly with the drain open such that remaining water, including water absorbed within the fabric of the articles, is removed by centrifugal force.

(34) Stain Release Index

(35) Often referred to as SRI, this is a measure of how much of a stain is removed. An SRI of 100 means complete stain removal.

(36) The SRI values given herein were obtained as follows. The colour of the stains was measured, both before and after washing, on a flatbed scanner and expressed in terms of the difference between the stain and an identical but clean cloth giving ΔE*(before wash) or ΔE*(after wash) values respectively. The ΔE values are the colour differences defined as the Euclidian distance between the stain and clean cloth in L*a*b* colour space. The ΔE*(after wash) values were then be converted to Stain Removal Index values by application of the standard transformation:
Stain Removal Index (SRI)=100−ΔE*(after wash)

EXAMPLES

(37) The following examples are provided by way of illustration and are not intended to limit the invention.

(38) The inventors have demonstrated that a power treatment demonstrably improves cleaning as compared to a comparable wash program without a power treatment. Further tests have demonstrated power treatments according to the invention often provide results not dissimilar to those associated with direct product application across a wide range of stains. The inventors have observed enhanced cleaning performance when the power treatment is carried out at elevated temperature (the solution is heated before it is sprayed) and/or with agitation.

(39) The inventors have also found that, advantageous, shorter subsequent wash cycles may be permitted, with comparable or often superior results for power treatment +½ wash as compared to a normal wash cycle. As a consequence, less water and/or energy can be used.

(40) The inventors have observed that these effects are even more pronounced using the compositions as described herein. The inventors have further observed that, while compositions including a coactive as claimed significantly improve the power treatment results, they also provide equivalent performance to comparative formulation without said coactive in normal washes. This both demonstrates that the inclusion of coactive acts synergistically with the power treatment, and shows that, even if no additional detergent is added, the formulations comprising a coactive as claimed are suitable for use in the normal wash step that typically follows the power soak.

(41) The inclusion of a coactive (in this case, CAP-B) was compared to a comparison formulation across a variety of LAS/LES/NI ratios. In each case, the laundry product contained 10 wt % surfactant system (either 10 wt % LAS/LES/NI or 8 wt % LAS/LES/NI+2 wt % CAP-B). In each case, a power treatment was performed as follows to assess the performance.

(42) Products as described were evaluated for their stain removal performance at a usage level of 1.7 g per litre. In advance of the normal wash process one part product was diluted with five parts water then used to power treat the stained monitors and ballast fabric, totalling 40 g per litre, at room temperature. Once the power treatment had been absorbed into the fabric load a holding step of 20 minutes was used, after which all fabric was washed for 30 minutes in water conditioned to 30° C. with no further product addition.

(43) TABLE-US-00001 Surfactant ratio LARD SRI LARD SRI LAS/LES/NI No co-surfactant With CAP-B 25/75/0 65.72 67.37 40/50/10 67.15 70.32 70/30/0 69.53 76.56 25/35/40 65.10 70.41

(44) Across the formulation space, a significant increase in performance was observed when CAP-B was included.

(45) The results presented below demonstrate that the upturn in performance is associated with the power treatment. Similar cleaning was observed in a normal “in wash” process for both formulations without a coactive and the formulation including CAP-B.

(46) TABLE-US-00002 Beef fat Lard Pottery clay 40/50/10 In- 65.54 70.73 68.40 wash 40/50/10 + CAP- 67.22 72.21 68.77 B In-wash 40/50/10 + CAP- 76.82 76.82 73.33 B Power Soak 25/35/40 In- 65.45 69.96 69.67 wash 25/35/40 + CAP- 65.70 70.49 69.69 B In-wash 25/35/40 + CAP- 75.07 73.85 73.89 B Power Soak