ES2659799T3 - Ultrasonic cleaning procedure - Google Patents

Abstract

An ultrasonic procedure for cleaning dirty dishes in an automatic dishwashing machine or cleaning dirty clothes items in a laundry machine using; 1) a programmed wash cycle selected in the dishwasher or automatic laundry machine; 2) a detergent composition comprising a bleach precursor; 3) water; and 4) ultrasonic energy having a frequency between 20 kHz and 1 MHz; in which an ultrasonic energy emitter is located within the machine's water circulation system and ultrasonic energy is not applied directly to dirty dishes or clothes, and in which ultrasonic energy is used to activate the precursor bleach in the wash liquor, the wash liquor being created from the addition of the detergent composition to the water, in which the ultrasonic energy has a power of between 1 mW and 1 W.

Description

5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

DESCRIPTION

Ultrasonic cleaning procedure

In recent years, environmental and cost-saving pressures have led to the automatic machine cleaning industry offering new automatic dishwashing and laundry machines that have "Eco" washing profiles.

These eco programs generally involve shorter and much colder wash cycles than those that have been the case before. Conventional washing temperatures typically reach 65-70 ° C in dishwashers and up to 95 ° C in laundry machines.

This contrasts the new eco cycles, in which wash temperatures can reach a maximum of only 30 ° C. This decrease in washing temperature can provide significant energy savings.

In addition, as a result of the same environmental pressures, the amount of washing water used per wash cycle by modern machines has also decreased at a steady pace in recent years. The new dishwasher machines now normally only use approximately 5 l of water per cycle. However, these changes have brought challenges for detergent manufacturing companies to provide automatic dishwashing (LVA) and laundry detergents that are effective at these new lower cycle temperatures. Current detergent compositions have been optimized to work at much higher temperatures (60-70 ° C).

One of the biggest challenges within this entire framework of challenges (others include enzyme performance and surfactant performance) is how to provide effective bleaching performance at these new lower wash temperatures.

Typically, automatic dishwashing and laundry detergents include a bleach to provide effective stain removal performance. Oxygen-based (non-chlorine) bleaches are generally favored for use in LVA and laundry. For stability, these are provided in precursor form, for example, these include peracid-based compounds such as percarbonates. The precursor decomposes in situ to generate the bleach (hydrogen peroxide) in the wash liquor.

To allow this reaction to occur at viable wash temperatures, both catalysts (usually transition metal) and activators (eg, TAED) of bleaching can be added to the detergent composition. Even with these additives this reaction is not completely effective until the reaction temperature reaches at least about 60 ° C and the bleaching performance decreases significantly even at 50 ° C. This is because the decomposition reaction is very temperature sensitive.

It is the object of the present invention to try to solve this problem.

In its broadest scope, the invention comprises the use of ultrasonic energy to activate a bleach precursor in an aqueous cleaning system, in which the ultrasonic energy is not applied directly to the articles to be cleaned.

The aqueous cleaning system may comprise an automatic dishwashing machine or an automatic laundry machine.

The aqueous cleaning system can also comprise a small portable device for activating the bleach at low temperatures for manual dishwashing, handwashing and cleaning of hard surfaces of the home in general.

Preferably, the ultrasound is capable of activating the bleach precursor at low temperatures. Specifically, low temperature for the purposes of the present invention means between 10 and 50 ° C. More specifically it means between 20 and 40 ° C.

In general, the term "ultrasound" or "ultrasonic" applied to sound refers to anyone above the audible sound frequencies and nominally includes any above 20,000 Hz. For example, the frequencies used for diagnostic ultrasound scans Medical can be extended to 10 MHz and more.

For the purposes of all embodiments of the present invention, ultrasound refers to any sound frequency between 20 kHz and 1 MHz. The invention is effective over the entire range of this spectrum. An ultrasonic procedure for cleaning dirty dishes is provided in a dishwasher or automatic washing machine using; a programmed wash cycle selected in the automatic dishwasher; a detergent composition comprising a bleach precursor; Water; and ultrasonic energy; wherein the ultrasonic energy is not applied directly to the dishes or dirty laundry and in which the ultrasonic energy is used to activate the bleach in the wash liquor as defined in claim 1. The use of ultrasound in dishwashing is generally well known. EP 1 062 904 A1 discloses an ultrasonic method of

5

10

fifteen

twenty

25

30

35

40

Four. Five

fifty

Cleaning of dirty items. For examples, WO 93/06947 discloses an improved dishwasher system. US20070131250 A1 discloses an ultrasonic drying mechanism for a dishwasher. US 5,218,980, US 3,854,998 and US 3,709,732 disclose dishwasher systems that incorporate ultrasonic generators to provide cleaning.

A more recent disclosure regarding ultrasonic dishwashing is US2009120474 A1.

It is generally accepted that ultrasonic methods work by providing localized heat and cavitation bubbles that provide localized scrubbing effects.

The difference between the use of ultrasound in the prior art and the use of ultrasound in the present invention is in its application. In the prior art, ultrasound has been used to directly treat the surface of the dishes to be cleaned. The dirty dishes rest in a liquid medium and the sound waves go to the dishes or clothes.

The ultrasound is used in the present invention to activate a bleach precursor in the wash liquor, then the wash liquor is used as normally inside the dishwasher or laundry machine. That is, the liquor can be pumped around and sprayed on dishes or other dishes or articles of clothing. Ultrasonic energy is not used directly on dishes or dirty laundry.

Without wishing to be bound by any theory, applicants believe that ultrasound reduces the energy barrier for decomposition of the bleach precursor. This allows the formation of the active bleaching species at a much lower temperature than would normally be possible. Alternatively, ultrasound can provide an alternative route for decomposition.

The term bleach refers to a large number of chemicals that remove color, bleach or disinfect. There are two broad classes of common bleach. Those based on chlorine and those based on oxygen.

For the purposes of the present invention, oxygen-based bleaches are preferred.

Most oxygen-based bleaches are based on hydrogen peroxide. Due to its reactivity, hydrogen peroxide is not normally used directly in detergent compositions. Normally a more stable precursor is used that can decompose into hydrogen peroxide when necessary.

Non-limiting examples of common oxygen-based bleach precursors include sodium percarbonate, sodium perfosphate, sodium perborate, sodium persulfate and urea peroxide.

Other non-limiting examples are organic peracids. These are also traditionally used as bleach in detergent compositions. Preferred examples include perbenzoic acid and peroxycarboxylic acids especially mono- or diperoxyxtalic acid, 2-octyldiperoxysuccinic acid, diperoxidedecanedicarboxylic acid, diperoxy-azelaic acid, 6-phthalimidoperhexanoic acid (PAP) and imidoperoxycarboxylic acid and the derivatives and mixtures thereof and salts and mixtures thereof.

The bleach precursor may be present between 1 and 50% by weight of the detergent composition, preferably between 5 and 30% by weight and more preferably between 10 and 25% by weight of the detergent composition.

The amount of detergent composition used per wash cycle may be between 5 and 100 g, preferably between 10 and 75 g and much more preferably between 15 and 50 g per wash cycle.

The present invention is not limited to particular bleach precursors and can also be used with a combination of two or more different bleach precursors.

It has been found that the use of ultrasound stimulates bleach formation at lower temperatures. Applicants have discovered significant increases in bleaching power through the use of ultrasonic energy in dissolved bleach precursors.

The ultrasonic cleaning procedure is effective in a wide range of temperatures. The disclosed process can be effective even when low temperature "ECO" cycles are used in newer machines.

The described procedure can be effective when washing temperatures below 50 ° C are selected. The procedure can be used even when wash temperatures below 40 ° C are selected.

The described process can be effective between 10 and 75 ° C, more preferably between 20 and 50 ° C and much more preferably between 30 and 40 ° C.

The process preferably includes a bleach activator. A preferred bleach activator is tetraacetyl ethylene diamine (TAED).

5

10

fifteen

twenty

25

30

Other bleach activators that may be included are one or more of an N- or O-acyl compound, an acylated diamine alkylene, tetra acetyl glyceryl, N-acylated hydantoin, hydrazine, triazole, hydratriazine, urazole, di-ketopiperazine, sulfurylamide, cyanurate , a carboxylic acid anhydride, sodium-acetoxy-benzene sulfonate, sodium-benzoyloxy benzene sulfonate (BOBS), sodium-lauroyloxy-benzene sulfonate (LOBS), sodium-isononanoyloxy benzene sulphonate (iso-NOBS) derivatives of Acylated sugar, pentaglucose and sodium-nonanoyloxy benzene sulphonate (NOBS) or combinations thereof.

The bleach activator may be present between 0.1 and 5% by weight of the detergent composition.

The process may include the use of a bleaching catalyst. Any suitable bleaching catalyst can be used, for example, manganese acetate, manganese oxalate or dinuclear manganese complexes such as those described in EP-A-1,741,774.

The bleaching catalyst may be present between 0.01 and 1% by weight of the detergent composition.

Any detergent composition suitable for use in an automatic machine or dishwasher comprising a bleach precursor may be used in the present process. Example LVA compositions can be found that can be used in the present invention in WO 2008/075084. These are incorporated herein by reference.

The detergent composition comprises one or more of the following additional components, colorant, binder, detergency adjuvant, surfactant, preservative, perfume, phosphonate and / or polymers.

The compositions used are preferably phosphate free.

A suitable commercial example of dishwashing formulations would be the brand of Finish ™ dishwasher tablets.

In a third aspect, an automatic dishwasher is provided comprising an ultrasonic source, in which the ultrasound emitter is positioned such that the emitted ultrasound does not come into contact with the items to be cleaned directly.

Preferably, the emitter is placed in the water flow system, so that the wash liquor cycles through the emitter many times during the wash cycle. This also ensures that the ultrasound does not come into contact with the items to be cleaned.

Preferably, the emitter will only be activated during the low temperature wash cycles.

Experimental

The activation of ultrasonic bleach precursors was studied through IR analysis of the degradation of a dye, Orange II. The precursor and the dye are placed together in an IR cell and the color loss of the dye is monitored over time.

The loss of color of the dye correlates with the activation of the bleach precursor in the active bleaching species, since the active bleach rapidly degrades the dye.

The results can be seen in the table below:

 Frequency

 Temperature Content% Degradation of the dye

 Control - Without ultrasound

 40 ° C White 0%

 40 ° C PCB / TAED 44%

 30 ° C PCB / TAED 22%

 20 ° C PCB / TAED 10%

 20 kHz

 40 ° C White N / A

 40 ° C PCB / TAED 76%

 30 ° C PCB / TAED 79%

 20 ° C PCB / TAED 81%

 580 kHz

 40 ° C White 11%

 40 ° C PCB / TAED 78%

 30 ° C PCB / TAED 39%

 20 ° C PCB / TAED 21%

 864 kHz

 40 ° C White 13%

 40 ° C PCB / TAED 71%

 30 ° C PCB / TAED 55%

5

10

fifteen

twenty

25

30

35

(continuation)

 Frequency

 Temperature Content% Degradation of the dye

 20 ° C PCB / TAED 15%

39 ml of water obtained by reverse osmosis was heated at 5 ° C above the experimental temperature. 5 ml of TAED solution (final concentration 0.144 g / l) was added to the water, followed by 1 ml of orange solution II (final concentration 2 ppm) and, finally, 5 ml of percarbonate solution (final concentration 0.564 g / l). Either ultrasound or stirring was applied with the reaction temperature maintained at 40, 30 or 20 ° C ± 1 ° C.

Samples were taken at 30 minutes and the absorbance was measured at 482 nm.

In the target controls: the TAED and percarbonate solutions were replaced with 6 ml of water and 4 ml of sodium carbonate solution (final concentration 0.32 g / l, to adjust the pH to> 10).

The total volume of each experiment was 50 ml.

The initial pH of the TAED / PCB experiments was 10.1-10.4. For whites (with added sodium carbonate) it was 10.3-10.5.

The power transferred to the experimental system by ultrasound was determined by calorimetric measurements. Two different sources were used for ultrasound generation. The 20 kHz sound was produced by a Sonic & Materials Inc. probe, # VCX600 and the two highest frequencies by a Meinhardt Ultrschalltechnik frequency generator # HM8001-2 in combination with a power amplifier # M11-010.

The two devices produced quite different power outputs, the 20 kHz signal provided 21 watts to the experimental system, while the higher frequency generator provided 0.8-1.2 watts, much less, to the experimental system.

This can provide the explanation for the remarkable increase in performance at lower temperatures (20 ° C) than the 20 kHz signal showed.

The results clearly demonstrate the activation power of ultrasound at low temperatures making this a very effective way to increase the cleaning performance in automatic dishwashing under ECO conditions.

The results also show that the bleaching performance can ultimately be controlled through the control of the power of the ultrasound used.

Preferably, the ultrasonic energy applied to the wash liquor was at least 0.5 watts as measured colorimetrically.

Preferably, the ultrasonic energy applied to the wash liquor was in the range between 0.5 and 100 watts, more preferably between 10 and 50 watts and much more preferably between 20 and 30 watts as measured colorimetrically.

The above power figures are based on those used in the test bath (~ 3.5-4 l).

If the emitter is to be used within a confined space within the device, such as a tube, the washing liquor flowing through the emitter many times during the washing procedure for continuous activation, much more energy levels may be necessary. low. The ultrasonic energy supplied was between 1 mW and 1 W, preferably between 10 mW and 500 mW and much more preferably between 50 mW and 200 mW.

Claims (14)

5 10 fifteen twenty 25 30 35 40 1. An ultrasonic procedure for cleaning dirty dishes in an automatic dishwashing machine or cleaning dirty clothes items in a laundry machine using; 1) a programmed wash cycle selected in the dishwasher or automatic laundry machine; 2) a detergent composition comprising a bleach precursor; 3) water; Y 4) ultrasonic energy having a frequency between 20 kHz and 1 MHz; in which an ultrasonic energy emitter is located within the machine's water circulation system and ultrasonic energy is not applied directly to dirty dishes or clothes, and in which ultrasonic energy is used to activate the precursor bleach in the wash liquor, the wash liquor being created from the addition of the detergent composition to the water, in which the ultrasonic energy has a power of between 1 mW and 1 W. 2. The method of claim 1, wherein the ultrasonic energy has a power of between 10 mW and 500 mW. 3. The method of claim 2, wherein the ultrasonic energy has a power of between 50 mW and 200 mW. 4. The method according to any of the preceding claims, wherein the bleach precursor is an oxygen bleach precursor. 5. The method of claim 4, wherein the bleach precursor is a percarbonate. 6. The method of claim 5, wherein the bleach precursor is sodium percarbonate. 7. The method according to any of the preceding claims, wherein the temperature of the wash liquor is below 50 ° C during the entire wash cycle. 8. The method according to any of the preceding claims, wherein the temperature of the wash cycle is below 45 ° C during the entire preprogrammed wash cycle. 9. The process according to any of the preceding claims, wherein the detergent composition comprises a bleach catalyst, preferably wherein the bleach catalyst is manganese oxalate. 10. The method according to any of the preceding claims, wherein the detergent composition comprises a bleach activator. 11. The method according to claim 10, wherein the bleach activator is TAED. 12. The method according to any of the preceding claims, wherein the detergent composition comprises one or more of the following components: colorant, binder, detergency adjuvant, surfactant, preservative, perfume, phosphonate or polymer. 13. An automatic dishwashing machine comprising an ultrasonic energy emitter, in which the ultrasonic emitter is positioned such that the emitted ultrasonic energy cannot find the items to be cleaned directly but is located within the circulation system of water from the machine, and in which the ultrasonic emitter is designed to emit ultrasound with a frequency between 20 kHz and 1 MHz and to activate a bleach precursor in a wash liquor that is created from the addition of a water detergent composition in the machine, in which the ultrasonic energy has a power of between 1 mW and 1 W. 14. The use of ultrasound having a frequency between 20 kHz and 1 MHz to activate a bleach precursor in an automatic dishwashing machine or automatic laundry machine, in which the ultrasonic energy is not applied directly to the articles a clean, but is located inside the machine's water circulation system, in which the ultrasonic energy has a power between 1 mW and 1 W.