BEST JONATHAN (GB)
CHOPRA-GANDHI SEEMA (GB)
MOORFIELD DAVID (GB)
PARRY ALYN JAMES (GB)
THORLEY DAVID CHRISTOPHER (GB)
UNILEVER NV (NL)
CONOPCO INC DBA UNILEVER (US)
| US5191669A | 1993-03-09 | |||
| US20030208852A1 | 2003-11-13 | |||
| US20100000024A1 | 2010-01-07 | |||
| EP1555340A2 | 2005-07-20 |
| Claims 1. A washing machine having a basket within a drum for receiving articles to be laundered, and a chamber, wherein the washing machine is configured to provide a cycle having the following steps: (i) combining detergent in water in the chamber to provide a detergent solution then (ii) spraying into the basket said detergent solution so as to dampen articles in the basket, characterized in that the amount of detergent solution sprayed into the basket is 600 mL or less per kilogram of articles to be laundered; and followed by (iii) a holding period of at least 5 minutes in which no water or further detergent solution is added to the basket containing the dampened articles. 2. A method of laundering articles, the method comprising: (i) combining detergent and water to provide a detergent solution, wherein the volume of detergent solution is 600 mL or less per kilogram of articles to be laundered then (ii) spraying into a washing machine basket the detergent solution so as to dampen articles in the basket; and (iii) waiting for a duration of at least 5 minutes during which no water or further detergent solution is added to the basket containing the dampened articles. 3. The washing machine of claim 1 or the method of claim 2, wherein the volume of the detergent solution is less than 5% of the total drum volume; optionally wherein the volume of the detergent solution is less than 1 % of the total drum volume; optionally wherein the volume of the detergent solution is less than 0.5% of the total drum volume. 4. The washing machine of claim 1 or claim 3, or the method of claim 2 or claim 3, wherein the volume of detergent solution is 500 ml or less per kg of articles to be laundered, optionally wherein the volume of detergent solution is 150 ml or less per kg of articles to be laundered. 5. The washing machine of claim 1 or any preceding claim dependent on claim 1 , wherein the washing machine is provided with a weighing apparatus for weighing articles in the basket, and wherein the washing machine is configured to determine the amount of water and / or detergent used in step (i) based on the weight of the articles in the basket. 6. The washing machine or method of any preceding claim, wherein the detergent is a liquid detergent product. 7. The washing machine or method of any preceding claim, wherein during the holding period the articles are agitated. 8. The washing machine or method of claim 7, wherein the agitation is achieved by rotation of the drum, optionally is at a rotation speed of 30 to 50 rpm, optionallywherein an on-off- reverse-off rotation pattern is used. 9. The washing machine or method of any preceding claim, wherein the detergent solution has a dilution factor of 40 or less. 10. The washing machine or method of any preceding claim, wherein the detergent solution has a surfactant concentration of at least 5,000 ppm, optionally at least 10,000 ppm, optionally at least 15,000 ppm, optionally at least 20,000 ppm. 1 1. The washing machine or method of any preceding claim, wherein step (ii) comprises spraying heated detergent solution; optionally wherein the temperature of the heated detergent solution is greater than 40 °C, optionally wherein the temperature of the heated detergent solution is around 60 °C. 12. The washing machine of any preceding claim, wherein the machine is configured to further provide a washing step following the holding period in which water is added to the drum; wherein no detergent is added during said washing step. 13. The washing machine of claim 12, wherein the washing step does not include heating. 14. The method of claim 2 or preceding claim dependent on claim 2, wherein the method further comprises a washing step (iv), the step comprising adding water to the drum and agitating the articles, wherein no detergent is added during the washing step. 15. The method of claim 14, wherein the washing step does not include heating. |
This present application claims priority benefit of EP 15176603.7, EP 15176604.5, and EP 15176605.2, each filed 1 July 2015. Each of these is incorporated by reference in its entirety.
The invention relates to washing machines configured to provide a cycle comprising introducing into the washing machine basket a detergent solution so as to dampen articles in the basket, and to methods comprising such an introducing step to dampen articles in a washing machine basket.
Background
In the developed world, and increasingly in the developing world, laundry is achieved using a washing machine. Broadly, washing machines can be divided into two classes: horizontal axis washing machines, in which the drum rotates about a horizontal axis, and vertical axis washing machines, in which the drum rotates about a vertical axis. Mostly commonly, horizontal axis washing machines are front loading, while vertical axis machines are top loading, although hybrid top loading machines having a horizontal axis are known.
Traditionally, heavily stained garments are pre-soaked prior to loading into the washing machine, usually in a solution of detergent and / or other stain remover ("product"). However, this is time consuming and laborious, and often messy as dripping articles are transferred from sink or tub into the washing machine.
Some modern machines include programs having a "prewash" function. The prewash is typically a shorted wash cycle in which product is used. A prewash may be consider a pre- soaking of articles in the washing machine prior to the main wash cycle. Such prewashes increase program duration and energy and water consumption.
For tough stain removal, consumers are often sceptical of the cleaning results they can achieve in a washing machine, even with a conventional prewash cycle. This is particularly true of vertical axis washing machines. As a consequence, consumers will often directly apply product to stains. Sometimes, this is neat laundry detergent, although specially designed direct application products, for example, stain removal sprays, are available. This direct application is usually perceived to be the most effective pre-treatment for stubborn stain removal.
However, in a wash load of heavily-stained articles this direct application can be an
inconvenient and time-consuming process. It can also be expensive as significant amounts of product will be used. Furthermore, it can often be wasteful and / or lead to increased detergent loads, leading to too much foaming during the subsequent wash cycle. In turn, greater amounts of product will often be used as consumers "double dose" (i.e. pre-apply and use a normal recommended amount for the wash.
Furthermore, all of these "before machine wash" application methods increase consumer exposure to products (for example, carrying articles between the sink and machine, or spraying a solution from a bottle). Summary
The invention is a result of the inventors' insight that there is an unmet need to provide washing machine programs having a pre-treatment step (prior to the main wash cycle) that more closely mimics the results of direct product application to stains. The inventors have determined that a factor in the efficiency of such a pre-treatment step is the concentration of product applied to the fabric. The inventors have recognised that conventional washing machine designs are not optimally configured to permit sufficiently high concentrations of product in a pre-treatment step without requiring very large amounts of product. This is because traditional washing machines deliver the product to articles in large volumes of water, not least because of the need to fill the void between the basket and drum. This leads to problems associated with waste (resulting in expense and environmental concerns), overproduction of foam during the subsequent wash cycle, and difficulties in rinsing the product from the fabric. The invention therefore relates to washing machines configured to provide a cycle within a program in which articles to be laundered are dampened by a solution of detergent. This cycle is referred to herein as a "power treatment".
Importantly, the volume of detergent solution used is sufficient to dampen the articles, but the cycle does not include soaking the articles. In other words, during the power treatment there is no or substantially no free solution in the drum: all or substantially all of the solution is absorbed by the articles. As a consequence, only very small volumes of solution are used, maximising efficacy.
Advantageously, this means that high temperature power treatments can be used without large energy consumption, because the amount of liquid being heated is small. This in turn allows access to the benefits of high temperature stain removal without compromising energy efficiency.
In conventional washing machines, the basket that holds the articles in the machine sits within an outer drum that is filled with the detergent solution. As the volume between the basket and the outer drum needs to be filled before the clothes can be wetted, the solution is necessarily dilute. This is especially true of vertical axis machines.
The inventors address this problem by the provision of a washing machine configured to provide a cycle in which articles to be laundered are dampened by a solution of detergent (a power treatment). This cycle is suitably followed by the addition of more water and a wash cycle. Suitably, the detergent used in the power treatment is used as the sole detergent in the subsequent wash cycle. However, it will be appreciated that additional detergent may be added during the subsequent wash cycle. It will be appreciated that, whether or not additional detergent is added in the subsequent wash cycle, other products, for example, fabric softeners may be added.
Accordingly, in a first aspect the invention provides a washing machine having a basket within a drum for receiving articles to be laundered, and a chamber, wherein the washing machine is configured to provide a cycle having the following steps:
(i) combining detergent and water in the chamber to provide a detergent solution, then
(ii) introducing into the basket said detergent solution so as to dampen articles in the
basket; followed by
(iii) a holding period in which no water or further detergent solution is added to the basket containing the dampened articles.
Combining detergent and water will lead to dissolution. Preferably the dissolution is complete (i.e. the solution is homogeneous). By providing a chamber in which the detergent solution is pre-combined, usually pre-dissolved, the homogeneity of the detergent solution is improved, which is important at the high concentrations made possible by the invention. Preferably, the detergent is a liquid detergent product. Use of a liquid detergent improves homogeneity and avoids the presence of particulates and sediment formation, which may clog the pipe connecting the chamber to the basket interior and / or the nozzle used for spraying. Of course, use of a detergent product in powder form is also envisaged. In step (ii), detergent solution is introduced directly into the basket, where it is adsorbed onto and absorbed into the fabric of the articles so as to dampen them. Suitably, it is sprayed, although other introduction methods may be envisaged. The introduction method suitably ensures that the detergent solution is applied to the articles so as to ensure good coverage, thereby dampening them. Accordingly, suitably the detergent solution is introduced into the basket as dispersed droplets. Suitably, the washing machine comprises one or more delivery means configured to generate droplets as the detergent solution enters the basket from the chamber. These will typically be nozzles.
It is not intended that the amount of detergent solution sprayed is sufficient to saturate the articles such that there is free solution. Consequently, there is minimal loss of detergent solution from the basket to the outer drum. Suitably, less than 25% by volume of the detergent solution is lost to the outer drum, preferably less than 20%, more preferably less than 15%, more preferably less than 10%, mostly preferably less than 5%. The first aspect may also be described as a washing machine having a basket within a drum for receiving articles to be laundered, and a chamber, wherein the washing machine is configured to provide a cycle having the following steps:
(i) combining detergent and water in the chamber to provide a volume of a detergent
solution, then
(ii) introducing into the basket said volume of detergent solution; immediately followed by
(iii) a holding period in which no water or further detergent solution is added to the basket.
As explained above, the volume of detergent solution used is relatively small. Suitably, the volume of detergent solution is less than 5% of the total drum volume, preferably less than 3%, more preferably less than 1 %. For example, it may be less than 0.9% of the total drum volume, less than 0.8%, less than 0.7%, less than 0.6% or even less than 0.5%. As high concentrations are observed to typically improve performance, preferably the volume of detergent solution is less than 0.5% of the total drum volume.
Accordingly, in some embodiments, the volume of the chamber is less than 5% of the total drum volume, preferably less than 3%, more preferably less than 1%. For example, it may be less than 0.9% of the total drum volume, less than 0.8%, less than 0.7%, less than 0.6% or even less than 0.5%. It will be appreciated that some headspace in the chamber may be desirable during step (i). Accordingly, the volume of the chamber may be less than 7.5% of the total volume of the drum, for example less than 4.5%, less than 1.5%, less than 1 %, less than 0.8%, less than 0.6%.
For example, for a domestic washing machine, preferably the amount of detergent solution is 1 I or less, for example 900 ml or less, 800 ml or less, 700 ml or less, 600 ml or less, or 500 ml or less. Smaller volumes are preferred as these permit high concentrations of detergent and reduce the energy needed to heat the solution if applicable.
It will be understood that the optimum volume of detergent solution will depend on the type and/or quantity of articles to be laundered. The articles may be characterised by their "dry" (i.e. pre-power treatment) weight in kilograms.
Although domestic machines often have rated capacities of around 7 kg of dry weight articles, in practice it is often difficult to load the machines with that amount of material. As a result, the dry weight of a conventional load is likely to be less, around a few kilograms. Suitably, the volume of detergent solution is 750 ml or less per kg of articles to be laundered, for example 700 ml or less, for example 600 ml or less, for example 550 ml or less, for example 500 ml or less, for example 450 ml or less, for example 400 ml or less, for example 350 ml or less, for example 300 ml or less, for example 250 ml or less, for example 200 ml or less. In some embodiments, the volume of detergent solution is 150 ml or less per kg of articles to be laundered, for example 140 ml or less, for example 130 ml or less, for example 120 ml or less, for example 110 ml or less, for example 100 ml or less, for example 50 ml or less.
For most fabrics, a volume of 150 ml or less per kg, preferably 100 ml or less per kg, provides good results.
In many cases, the amount of detergent used and volume of water used will be fixed for consumer ease, regardless of the weight of the laundry load.
However, adjusting the amount of detergent and / or volume of water used to make the detergent solution in step (i) increases efficiency and economy and reduces waste. Accordingly, in some embodiments the washing machine is configured to perform a pre-step of weighing the articles present in the basket and determining, based on said weight, the amount of water to be added to the chamber in step (i), based on pre-programmed values. Naturally, if a fixed amount of detergent product is added by, for example, the user, then the concentration of the detergent solution will vary.
It may also be desirable to adjust the amount of detergent product used. Accordingly, in some embodiments the washing machine is configured to perform a pre-step of weighing the articles present in the basket and determining, based on said weight, the amount of detergent product to be added to the chamber in step (i), based on pre-programmed values. Suitably, in these embodiments, the washing machine is provided with a reservoir for housing detergent product, the reservoir being in fluid communication with the chamber, with a valve provided between the reservoir and the chamber that is configured to meter amounts of detergent product. It will be appreciated therefore that in some embodiments the washing machine has a weighting apparatus for weighing articles in the basket.
Suitably, the washing machine has a processor configured to provide a cycle or method of laundering articles in said washing machine as described herein. Suitably, the processor is provided with a computer program configured to provide a washing machine cycle or method of laundering articles in said washing machine as described herein. Suitably, said cycle is a cycle in a wash program, and is followed by a wash cycle.
As has been explained herein, an advantage of the relatively very small water volumes is that high concentration detergent solutions can be used in the power treatment.
The inventors have found that certain detergent solution concentrations show especially advantageous effects. Different optimum concentrations may be used for different stain types. Suitably, the dilution factor is 40 parts water to 1 part detergent product (dilution factor = 40), or less. Or less in this context means 40 parts water or fewer to 1 part detergent product.
Preferably, the dilution factor is 35 or less, preferably 30 or less. In some embodiments, the dilution factor is 25 or less, for example, 20 or less. The inventors have determined that for many applications, a dilution factor of around 15 provides a good balance between performance and economy. Accordingly, in some embodiments, the dilution factor of the detergent solution is about 15. For some stains, and indeed for some wash programs and machines, higher concentrations may be preferable. Accordingly, in some embodiments, the dilution factor may be as low as 10 or less, for example, 9 or less, 7 or less, 5 or less, or even around 2. For example, the dilution factor may be 5 to 40, preferably 5 to 20. In some embodiments, the dilution factor is 5 to 15, or even as low as 5 to 10. In some embodiments, the dilution factor is 2 to 10, for example 2 to 7, for example 2 to 5.
Suitably, the amount of surfactant in the detergent solution used in the power treatment is at least 5,000 ppm, preferably at least 6,000 ppm, for example at least 7,000 ppm. Even higher surfactant amounts may be preferred, for example at least 10,000 ppm, for example at least 12,000 ppm. In some embodiments, the amount of surfactant is at least 15,000 ppm, for example as high as 20,000 ppm, 30,000 ppm, 40,000 ppm or even as high as 50,000 ppm. It will be appreciated that these surfactant values are significantly higher than those used in normal wash cycles (which typically have surfactant values in the regions of several hundred ppm). The values are also higher than convention pre-wash cycles and "soak" processes (where the articles are first soaked in a sink or similar). During step (ii), while the detergent solution is being introduced (for example, sprayed), the drum may undergo rotation and / or reciprocation to facilitate effective dampening of the articles and to assist an even coverage of the detergent solution across all of the articles. A vertical axis machine may additionally or alternatively undergo a shaking (side-to-side and / or up-and- down) motion. Additionally or alternatively, in the case of vertical machine having an agitator the agitator may rotate and / or reciprocate. In other words, it is preferable that, during spraying, the articles are continuously redistributed, for example, by "tumbling", in the drum so as to improve detergent solution coverage.
Step (ii) is followed by a holding step (step iii). Suitably, the holding step is more than a few minutes' duration, for example, the holding step duration may be at least 5 minutes, for example at least 10 minutes or at least 15 minutes. For example, the holding step duration may be 5 minutes to 30 minutes, for example 10 to 20 minutes.
The inventors have observed that enhanced stain reduction is achieved when the drum is held steady (i.e. without movement) during the holding step (step iii), as compared to a comparable washing machine program without a power treatment as claimed. If an agitator is present, it is not necessary that the agitator move during step (iii). Accordingly, step (iii) may be a holding period in which no water or further detergent solution is added to the basket and wherein the basket remains stationary.
However, preferably some agitation is provided during step (iii). Accordingly, in some preferred embodiments, step (iii) comprises a holding period in which no water or further detergent solution is added to the basket and wherein the basket is agitated. Suitably, the basket is agitated for a period of at least 5 mins. In some embodiments, the basket is agitated for a period of at least 10 mins. This improves stain removal and cleaning performance, as described herein. This is thought to be because the agitation causes the articles to rub against each other, the basket and, if present, the agitator, working the detergent into the fibres of the articles and lifting stains.
In the case of horizontal axis machine, suitably the agitation is provided by the drum rotating and / or reciprocating during the holding step (step iii).
In some embodiments, the drum rotates at a rate of 10 to 150 rpm, for example, 10 to 100 rpm. Naturally, the drum rotation speed may depend on the size and type of machine. In some embodiments, the rotation speed is 15 to 90 rpm, preferably 30 to 50 rpm. It will be appreciated that the rotation speed may remain essentially constant during the power treatment, or may vary. For example, an on-off-reverse-off rotation pattern may be used. For example, the inventors have demonstrated enhanced effects for a power treatment having a 28s-2s-28s-2s pattern at 45 rpm. The inventors have found that improved stain removal for certain classes of stain is achieved when the detergent solution is heated. Owing to the small volumes of detergent solution used, only relatively small amounts of energy are needed to heat the detergent solution. As a result, benefits associated with higher temperature washes can be accessed without seriously impacting the environmental performance of the washing machine.
In some embodiments, the temperature of the detergent solution during spraying is greater than 25 ° C, preferably greater the 30 ° C, more preferably greater than 35 ° C. For example, the temperature may be around 40 ° C. In some embodiments, the temperature is preferably greater than 45 ° C, more preferably greater than 50 ° C, more preferably greater than 55 ° C. For example, the temperature may be around 60 ° C. Of course, higher temperatures are also envisaged. It will be appreciated that the temperature during spraying may be higher, such that the temperature of the solution contacting the articles is greater than 25 ° C, preferably greater the 30 ° C, more preferably greater than 35 ° C. For example, the temperature of the solution contacting the articles may be around 40 ° C. In some embodiments, the temperature is preferably greater than 45 ° C, more preferably greater than 50 ° C, more preferably greater than 55 ° C. For example, the temperature of the solution contacting the articles may be around 60 ° C.
It will be appreciated that in some embodiments, the washing machine may provide a means for selecting a preferred temperature. In other words, more than one power treatment program may be provided, each power treatment program having a different detergent solution temperature.
Accordingly, the chamber may comprise, or be connected to, a heater element. Additionally or alternatively, the solution may be heated while flowing from the chamber to the basket, for example, by an in-line heater. Suitable heating systems are known in the art. The washing machine may therefore additionally or alternatively comprise an in-line heater located along the fluid pathway between the chamber and the basket, configured so as to heat the detergent solution as it flows from the chamber to the basket.
The inclusion of a power treatment of the invention in a wash cycle has been shown to improve cleaning performance and tough stain removal. Typically, the power treatment is provided as part of a wash program, and is followed by a wash cycle. Accordingly, in some embodiments, the invention provides a washing machine having a basket within a drum for receiving articles to be laundered, and a chamber, wherein the washing machine is configured to provide a cycle having steps (i), (ii), and (iii) as described; and then a washing step in which water and optionally detergent are added to the drum. Suitably, volume of water added in the washing step is at least 5% of the total volume of the drum. The precise amount will depend on the machine and program settings, and may be at least 10%, at least 20%, or even more. For example, a top loading automatic machine may almost completely fill the drum with water. Advantageously, shorter washing steps may be used owing to the stain removal and cleaning facilitated by the power treatment than would normally be used. For example, the washing cycle may be so-called half wash. Advantageously, cooler washing steps may be used owing to the stain removal and cleaning facilitated by the power treatment. For example, even for tough staining, the washing step temperature may be 40 ° C or less, 35 ° C or less, 30 ° C or less, 25 ° C or less. In some preferred embodiments, no heating is used (unheated water is added): the washing step temperature is the temperature of the cold fill. Naturally, this will vary with supply and geographical variation, but may be as low as 10 ° C, or even lower. For example, in northern US states the water supply may be as low as 7 ° C or even 5 ° C in winter. This may be referred to as an ambient wash.
It will be appreciated that the power treatments of the present invention use high concentrations of detergent. Lower concentrations are used in washing steps. In preferred embodiments, no additional detergent is added in the washing step. In other words, only water is added. The detergent sorbed onto and into the articles following the power treatment is the only detergent present in the washing step.
This means that only one product is used, and only one product must be added to the machine. This reduces waste, improves economy, and enhances convenience for the consumer. It will be appreciated that the washing may be followed by a rinse phase and optionally a spin cycle.
As described herein, the washing machine of the invention may be a horizontal axis machine or a vertical axis machine. In some embodiments it is a horizontal axis washing machine. In some embodiments, it is a vertical axis washing machine.
The present invention also relates to methods of laundering articles.
Accordingly, in a second aspect, in invention provides a method of laundering articles, the method comprising:
(i) combining detergent and water to provide a detergent solution, then
(ii) introducing into a washing machine basket the detergent solution so as to dampen articles in the basket; and
(iii) waiting for a duration of time ("holding period") during which no water or further detergent solution is added to the basket containing the dampened articles. Suitably, the detergent and water are combined in a chamber in the washing machine. It will be appreciated that the method may also include placing articles to be laundered into the washing machine basket. The washing machine basket is located in a drum, as is conventional. The volume of the drum surround the exterior of the basket may be referred to as the "outer drum".
The second aspect may also be described as a method of laundering articles, the method comprising:
(i) combining detergent and water to provide a volume of detergent solution, then
(ii) introducing into the basket said volume of detergent solution; followed by
(iii) waiting for a duration of time ("holding period") during which no water or further detergent solution is added to the basket containing the dampened articles. The descriptions and optional and preferred features described above with reference to the washing machine of the first aspect will be understood to apply similarly (except where context clearly dictates otherwise) to the methods of the second aspect.
The following optional and preferred features are therefore described by way of illustration and not by way of limitation.
As in the first aspect, liquid detergent is preferred.
Relatively small volumes of water are used to make the detergent solution, and minimal loss of detergent solution to the outer drum (i.e. from the basket) is envisaged. Suitable values for percentage loss and volume are provided above. Suitably, the detergent solution is made in a chamber, as described above.
The method may include a weighing step (i.e. a pre-step of weighing the articles present in the basket and determining, based on said weight, the amount of water to be combined with the detergent, for example in a chamber, in step (i), based on pre-programmed values). As in the first aspect, the amount of detergent and / or water may be selected.
In some embodiments, the preferred dilution factors described above are used.
In some embodiments, the basket is static during the holding step, as described above.
Accordingly, in some embodiments, step (iii) comprises waiting for a duration of time (holding period) in which no water or further detergent solution is added to the basket, keeping the basket stationary.
In some embodiments, the holding step includes the provision of some agitation, as described above. Accordingly, in some embodiments, step (iii) comprises agitating the basket for a duration of time (holding period) in which no water or further detergent solution is added to the basket. The agitation may be continuous or intermittent.
Suitable holding periods and / or agitation means are described above.
The method may comprise providing a heated detergent solution. For example, step (i) may comprise combining detergent and heated water to provide a detergent solution (for example, at a temperature as described above). Step (i) may comprise combining detergent and water to provide a detergent solution, then heating said solution (for example, to a temperature as described above).
Suitably, the steps described above are followed by a washing step (iv), the step comprising adding water and optionally detergent to the drum and agitating the articles. Preferably, no detergent (i.e. only water is added) during the washing step. Preferably, nothing other than water is added during the washing. Suitable volumes and temperatures are described above.
The methods may be carried out in a horizontal axis machine or a vertical axis machine.
Detailed Description
The invention will be described with reference to Figure 1 , which shows schematically one how the basket, drum and chamber can be configured. 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 machines and methods of the invention also encompass vertical axis machines. 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. 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.
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. 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. 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.
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 Articles
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. Dampen
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.
Detergent
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 and regulators. The detergent products may be powders or liquids.
In some embodiments, the detergent product contains a builder. In some embodiments, the detergent product contains an enzyme. In some embodiments, the surfactant is not cationic.
Detergent Solution
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.
It will be appreciated that suitably the detergent solution contains surfactant and builder.
Direct application
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. Dilution factor
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).
Wash program
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.
Wash cycle
Also called a washing step, this is a wash cycle in which articles are agitated in an excess of detergent solution to clean them.
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.
Stain Release Index
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.
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 AE * (before wash) or AE * (after wash) values respectively. The ΔΕ values are the colour differences defined as the Euclidian distance between the stain and clean cloth in L * a * b * colour space. The AE * (after wash) values were then be converted to Stain Removal Index values by application of the standard transformation:
Stain Removal Index (SRI) = 100 - AE * (after wash)
Examples
The following examples are provided by way of illustration and are not intended to limit the invention.
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 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. EXAMPLE 1
A detergent product, formulated according to Table 1 , was used to compare the effect of temperature on "Power treatment" performance. This composition is referred to herein as composition X.
% w/w
Water To 100%
Monoproylene glycol 8.00
Nonionic (C12-14E07) 5.00
LAS Acid 3.33
Triethanolamine 2.00
EPEI 1.81
SLES (2EO)) 1.67
Sequestrant 0.88
Texcare 0.82
Empigen OB 0.50
Sodium hydroxide 0.35
Preservative 0.02 Table 1 : Composition X
The "main wash" condition represents the concentration of product experienced in a conventional main wash, the "power treatment" condition represents the use of the product composition X at a dilution of 5:1. For example, the following results were obtained using a liquid detergent product having a holding period of 15 min followed by a 20 minute ambient wash.
The results obtained are shown in Table 2:
Table 2
Underlined values are significantly better than the standard main wash process. Following an Analysis of Variance, significance testing was performed at the 95% confidence level using a Tukey HSD analysis method. Mean results are quoted as LSMEANS, i.e. have been adjusted to compensate for any covariance found.
EXAMPLE 2
The following shows a comparison a normal wash cycle program (in wash), a program including a soak in a top load appliance (vertical axis machine - TLA), a bowl soak (outside the machine), a power treatment and direct application at high and low volume. For a variety of detergent products, it can be observed that the results obtained using a power treatment of the invention are not dissimilar to direct application. Indeed, for some stains, the results are better. This is observed both for biological and non-biological detergents.
The following compositions were used:
Product A
Demin Water up to 100 %
Monopropylene glycol 8.00
Sodium hydroxide 0.35
Triethanolamine 2.00
Nonionic (Ci2-i 4 E07) 5.00 LAS Acid 3.33
SLES (2E0) 1.67
Empigen OB 0.50
EPEI 1.81
Texcare SRN-170 0.82
Acrylate thickening
1.50
polymer†
Product B
Demin Water up to 100 %
Triethanolamine 1.00
LAS Acid 3.00
SLES (1 EO) 9.00
Empigen OB 0.43
EPEI 1.55
Texcare SRN-170 0.53
Acrylate thickening
1 .50
polymer†
Table 3a shows a comparison of a simulated TLA wash process (25 °C, 20 min wash, 500 ml of 13 °FH water, 2x rinses, 25:1 liquorcloth equal weights of cotton and polyester ballast) using a tergotometer preceded by a number of different prewash protocols.
With the exception of the no pre-exposure treatment, cotton fabrics stained with cocoa milk were exposed for 20 minutes to 0.4g of each product at varying levels dilutions.
PRODUCT PRODUCT
PRODUCT A + PRODUCT B + protease
Dilution A protease (@ B (@ 0.5% factor 0.5% w/w) w/w)
No pre¬
N/A 76.1 81.4 76.8 82.6 exposure
TLA soak 1250 76.6 82.8 77.1 83.6
Bowl soak 137 77.9 85.7 78.6 86.8
"Power
10 82.4 89.1 84.6 90.1 treatment"
Directly 1 93.1 92.5 91.4 92.0 Applied (high
viscosity)
Directly
Applied (low 1 90.8 91.2 88.7 91.1 viscosity )†
† low viscosity products made by leaving out the thickening polymer from the compositions shown.
Table 3a - wash results (as SRI values)
Table 3b shows the comparison with a slightly different TLA wash process (as above but this time with only a 15 minute wash). As in the previous example, with the exception of the no preexposure treatment, cotton fabrics, this time stained with a dyed lard, were exposed for 20 minutes to 0.75g of each product at varying levels dilutions.
† low viscosity products made by leaving out the thickening polymer from the compositions shown.
Table 3b: wash results (as SRI values - bold underline indicates are significantly
improvements to no pre-exposure control)
Table 3c shows the comparison with the same protocol as in Table 3b but this time using an amylase sensitive stain (HP Brown Sauce) and an amylase enzyme.
PRODUCT A +
Dilution factor PRODUCT A amylase (@
0.5% w/w)
No pre-exposure N/A 82.8 84.6
TLA soak 667 82.9 84.6
Bowl soak 73 83.3 87.6
"Power treatment" 5 84.5 93.0 Directly Applied (high
1 85.6 94.3
viscosity)
Directly Applied (low
1 85.8 93.4
viscosity)†
Table 3c - wash results (as SRI values - bold underline indicates are significantly
improvements to no pre-exposure control)
Example 3
In particular, at certain concentrations, the power treatments of the present inventions perform better than direct application for certain stain, in particular fatty stains. Table 4 shows the results for lard and palm oil, demonstrating small but appreciable benefits.
The following results are from an experiment where a detergent product, formulated according to Table 1 , was used to compare the effects on fatty stains of the power treatment process with that from direct product application and the main wash.
The "main wash" condition represents the concentration of product experienced in a
conventional main wash, "direct application" the use of the neat, undiluted formulation whilst "power treatment" represents the use of the product at dilutions of 2:1 and 5:1. For example, th following results were obtained using a liquid detergent product having a holding period of 10 min with followed by a 20 minute ambient wash.
Table 4 Example 4
The inventors have found that, advantageously, the efficiency of the power treatment means that short wash cycles may be used in washing machine programs featuring a power treatment. In other words, a so-called "half wash" can be used, saving energy and water. Table 6 shows the improved response from a 15 minute power treatment and 15 minute "half wash" when compared with a "normal" 30 minute wash. The power treatment was performed with agitation.
In each case, a liquid detergent according to Table 5 was used at a dilution factor of 15. Water To 100%
Monoproylene glycol 8.00
Nonionic (C12-14E07) 5.00
LAS Acid 3.33
Triethanolamine 2.00
EPEI 1.81
SLES (2EO)) 1.67
Sequestrant (Dequest 2010) 0.88
Texcare 0.82
Empigen OB 0.50
Protease 0.40
Sodium hydroxide 0.35
Amylase 0.2
Mannanase 0.2
Preservative 0.02
Table 5: Composition Y
The results show a marked improvement, even with the half wash, for most stains. This represents a significant improvement in efficiency with no loss of cleaning performance and many cases significant improvements in tough stain removal.
Change in cleaning
(ASRI)
Black Coffee (on cotton) 2.48
Blackcurrant Juice (on cotton) 4.55
Black Tea (on polyester) 8.08
Grape Juice (on cotton) 8.08
Red Wine (on cotton) 8.23
White Tea (on cotton) 15.03
Black Tea (on cotton) 16.56
Chocolate Milkshake (on cotton) 0.36
Chocolate Pudding (on cotton) 3.08
Blood (on cotton) 3.36
Gravy (Instant) (on polyester) 4.65
Gravy (Instant) (on cotton) 5.14
Gravy (on cotton) 7.28 Cocoa/Milk (on cotton) 7.76
Annatto Oil (on cotton) 2.12
Green Curry (on cotton) 2.53
Tomato Ketchup (on cotton) 2.79
Yellow Curry (on cotton) 3.21
Ragu/Sunflower Oil (on cotton) 6.16
Red Curry (on cotton) 6.47
Mechanical Grease (on polyester) 7.62
Blue Paint (on polyester) 2.51
Red Soil (on cotton) 2.69
Blue Poster Paint (on cotton) 5.38
Yellow Pottery Clay (on polyester) 6.27
Red Pottery Clay (on polyester) 10.74
Table 6
Furthermore, the inventors have observed a significant and surprising upturn in cleaning benefit when the amount of water is reduced from 1 I per kg to 600 ml per kg across a variety of stains. These data are presented below.
The following data were obtained using the method similar to that described in Example 2 (Product A with amylase).
Table 7
Similar results were obtained for a second formulation (which also includes amylase).
Table 8 Liquid detergents are commonly preferred by consumers. They are also more convenient in some embodiments of the invention. For example, homogeneous solutions and more easily obtained and nozzles are less likely to be clogged. Furthermore, liquid products can be metered efficiently to provide certain amounts of detergent.
Liquid detergents have been shown by the inventors to provide better results than powders for a variety of stains.