NZ756433B2 - Cleaning composition - Google Patents

Abstract

composition for cleaning membranes used in food processing comprising an amine oxide and an alkyl sulfate, the composition maintaining good cleaning performance whilst leaving a low residue of surfactant on the membrane that is cleaned using the composition. A method of use of the composition is also presented. lso presented.

Description

Cleaning Composition Field of the Invention The invention relates to cleaning itions, more specifically to compositions for cleaning membranes used in processing food products. ound of the Invention In the food and beverage industry, it is important that the food and beverage products produced are of a suitable standard and purity for consumption by the public. The public will not accept ts that n al residues, such as those that remain after cleaning of the equipment used to produce a ular product. For example, it is not acceptable for food products to taste of the surfactants that were used to clean the equipment used to e the product.

Customer product quality is an increasingly important topic for high premium whey products such as infant food, for example, where it is critical that the ts are not contaminated with or contain potentially hazardous materials. It is currently possible to analyse products to detect such residues in parts per million (ppm) or parts per billion (ppb) scale to ensure that even trace s of undesirable or ous als are not present in dairy products in particular.

The need for minimising residue in food products must be balanced with the need to ensure thorough cleaning of the equipment. Where dairy products are processed through a membrane filter, the filtration processes are contingent on a consistent throughput of the dairy product across the membrane. Therefore, it is important that an effective and carefully chosen cleaning composition and cleaning regime is used to maximize membrane life and minimize premature replacement. Proper cleaning procedures directly affect productivity and production costs.

Currently, equipment that is used to produce high quality food products, such as membrane filters, are rinsed ghly to remove cleaning products. However, procedures required to remove cleaning compositions typically are lengthy and therefore, require considerable down time of the equipment between production runs.

Accordingly, it is one object of the invention to provide an improved cleaning composition that is used for cleaning membranes used to process food and beverage ts.

Summary of the Invention In a first embodiment there is provided a membrane cleaning composition comprising at least one amine oxide and at least one alkyl sulfate, wherein the at least one alkyl sulfate comprises 2-ethylhexyl sulfate and the at least one amine oxide comprises lauryldimethylamine oxide.

In a second embodiment there is provided a method of cleaning a membrane comprising the steps: a) providing a membrane cleaning composition according to the first embodiment; b) applying the membrane cleaning composition to a membrane; and c) rinsing the membrane to remove at least a majority of the composition from the membrane; wherein the membrane ses less than 50 mg/m2 of the cleaning composition after the step of rinsing the membrane.

In a third embodiment there is ed use of a ne cleaning ition according to the first embodiment to clean a membrane used to process a food product.

According to a first aspect there is provided a composition for use as a cleaning composition to clean membranes, the composition comprising at least one amine oxide and at least one alkyl sulfate, n less than 50mg/m2 of the composition is retained on a membrane cleaned using the composition.

The person skilled in the art will understand that the at least one amine oxide and the at least one alkyl sulfate are both surfactants. Accordingly, the composition of the invention comprises at least two different tants, a non-ionic tant and an anionic surfactant.

The cleaning composition may be used to clean membranes used to process food products or beverages. For example, the cleaning composition may be used to clean membranes used to process dairy ts, fruit juices or alcoholic beverages such as beer.

Typically, the membrane that is cleaned using the composition of the t aspect is rinsed using water after the application of the composition.

AH26(27097700_1):RTK Cleaning compositions used to clean membranes that are used to process food products typically leave a residue on the membranes, even after rinsing. This residue can then pass into the food products that are subsequently processed by the ne. For example, residue on membranes used to process beer or wine can be re-dissolved by the alcohol in the beverage.

In another example, residue on membranes used to process dairy products can be re-dissolved in the fats t in the diary dairy product. Accordingly, the cleaning composition can contaminate the product that is to be processed using the membrane.

The use of a cleaning composition to clean membranes used in food product processing that leaves less than 50 mg/m2 of surfactant on the membrane according to the present invention requires significantly less rinsing of the membrane to remove, for example, and is a iently low concentration to pose a reduced risk of contamination of dairy products uently sed by the membrane compared to uses of compositions known in the art to clean dairy product nes.

AH26(27097700_1):RTK It has been found by the inventors that the use of conventional cleaning products leaves a significant residue of the surfactants within the cleaning products which must be rinsed from the membrane before the membrane is used again, and in some instances, surfactant remains on the membrane even after extensive rinsing. In addition, surfactants that leave a low residue on the membrane after use typically have a reduced cleaning performance.

The adsorption and subsequent desorption of a surfactant to a surface depends on a variety of different factors. The material of the e, and more specifically the hilicity of the surface, would be expected to influence the adsorption behaviour of a surfactant onto a substrate. The macroscopic ure of the material might also be expected to impact the adsorption and desorption of a surfactant to a surface, therefore the amount of surfactant that remains on the surface after use. For example, results of a flat and even material compared to a porous ne could be expected to give different results. The pore size of a porous material such as a membrane may also be expected to produce different results, e.g. microfiltration membrane compared to ultrafiltration membrane. The ent molecular weight cut off of the membranes may lead to ent interaction of the membrane with the different-sized and structured tants. Accordingly, different sized pores on the same material membrane could lead to different residue result for a given surfactant.

Furthermore, for a given surface, the structure of a surfactant would also be ed to influence the adsorption and desorption to and from a e. Chain length, size of surfactant, and the electronegativity of the polar head groups may all influence the adsorption and desorption behaviour of the surfactant to a given surface and therefore to a given membrane.

It has been surprisingly found by the inventors that a cleaning composition comprising both at least one amine oxide and at least one alkyl sulfate provides both good ng performance of the membrane and a low e on the membrane after the cleaning process. Accordingly, use of the ition of the present invention allows a high quality clean of the membrane without requiring extensive rinses with water after the cleaning process, ing in reduced cleaning procedures and lower risks of contamination of the products.

Typically, less than 20 mg/m2 of the surfactants of the composition are ed on the membrane after use. Preferably, less than 10 mg/m2 of the surfactants of the ition are retained on the membrane after use. More preferably, less than 5 mg/m2 of the surfactants of the composition are retained on the membrane after use.

In some embodiments, the retained composition of the present aspect on a membrane may be 50% less than compositions comprising an amine oxide that do not comprise an alkyl sulfate. The retained composition of the present aspect on a membrane may be 75% less than compositions sing an amine oxide that do not comprise an alkyl sulfate. The retained composition of the present aspect on a membrane may be 90% less than itions sing an amine oxide that do not comprise an alkyl e.

It will be readily understood by the person skilled in the art that the term, "amine oxide" refers to oxides of tertiary amines having general formula (I): R1\ /+ N\ _ / 0 R2 (I) wherein R1 is selected independently from optionally substituted C4-C20 alkyl, R2 and R3 are ed independently from optionally substituted C1-C5 alkyl.

Suitable substituents are defined below.

The composition may comprise a plurality of amine oxides. Each amine oxide within the plurality of amine oxides may vary in chain length for one or more of R1, R2, or R3. For example, the composition may comprise a plurality of amine oxides comprising at least three amine oxides where R1 is C12 alkyl for a first amine oxide, R1 is C14 alkyl for a second amine oxide and R1 is C16 alkyl for a third amine oxide.

For example, the amine oxide may be ed from the list comprising: tetradecyldimethylamine oxide, lauryldimethylamine oxide, pentadecyldimethylamine oxide, imethylamine oxide, hexadecyldimethylamine oxide, octadecyldimethylamine oxide, or cocalkyldimethylamine oxide.

Typically, R1 is 012-016 alkyl. Preferably, R2 and R3 are 01.3 alkyl.

Preferably, the at least one amine oxide includes lauryldimethylamine oxide.

The composition may comprise from 10 to 2000 ppm of the at least one amine oxide. The composition may comprise from 10 to 1000 ppm of the at least one amine oxide. The composition may comprise from 10 to 500 ppm of the at least one amine oxide. The composition may comprise from 50 to 400 ppm of the at least one amine oxide. The composition may comprise from 100 to 400 ppm of the at least one amine oxide.

The composition may comprise at least 50 ppm of the at least one amine oxide. The composition may comprise at least 100 ppm of the at least one amine oxide. The composition may comprise at least 150 ppm of the at least one amine oxide.

The composition may be provided in a concentrated stock solution that is then diluted by the end user for use. Accordingly, the stock on may se 1 to 40 weight t of the at least one amine oxide. The stock solution may comprise 1 to 20 weight percent of the at least one amine oxide. The stock solution may be diluted before use such that the ition that is used to clean the membrane may comprise from 0.01 to 2 weight percent of the at least one amine oxide, or from 0.01 to 1 weight percent of the at least one amine oxide, for example.

Typically, the at least one alkyl sulfate has the general formula (II): OZ§~OWR4 0 (II) where R4 is selected from the group consisting of optionally substituted C4-C20 alkyl, and optionally tuted C4-C20 cycloalkyl.

The at least one alkyl sulfate may be a linear alkyl sulfate. ingly, R4 may be linear.

The at least one alkyl sulfate may be a branched alkyl sulfate. Accordingly, R4 may be In some embodiments, R4 may be optionally substituted 05-045 alkyl. R4 may be optionally substituted Cs to C10 alkyl.

Preferably, the at least one alkyl sulfate comprises 2-ethylhexyl sulfate.

The composition may comprise from 10 to 1000 ppm of the at least one alkyl sulfate. The composition may comprise from 10 to 500 ppm of the at least one alkyl sulfate. The composition may comprise from 10 to 300 ppm of the at least one alkyl sulfate. The composition may comprise from 50 to 200 ppm of the at least one alkyl sulfate. The composition may comprise from 50 to 100 ppm of the at least one alkyl sulfate.

The composition may comprise at least 50 ppm of the at least one alkyl e. The composition may comprise at least 75 ppm of the at least one alkyl sulfate.

In some embodiments, the composition may be ed in a concentrated stock solution that is then diluted by the end user before use. Accordingly, the stock solution may comprise 1 to 40 weight percent of the at least one alkyl e. The stock solution may comprise 1 to 20 weight percent of the at least one alkyl sulfate. The stock solution may then be diluted before use such that the composition that is used to clean the membrane may se from 0.001 to 2 weight percent of the at least one alkyl sulfate or from 0.05 to 1 weight percent of the at least one alkyl sulfate, for example.

The at least one alkyl sulfate is preferably in salt form. Typically the counter ion of the salt form of the at least one alkyl sulfate is a monovalent counter ion. The counter ion may be an alkali metal, such as sodium, or potassium. The counter ion may be any other suitable counter ion, such as um, for example.

Most preferably, the composition comprises lauryldimethylamine oxide and 2-ethylhexyl sulfate. The composition may comprise from 100 ppm to 1000ppm lauryldimethylamine oxide and the ition may se from 50 ppm to 500ppm 2-ethylhexyl sulfate. The composition may comprise from 100 ppm to 500 ppm lauryldimethylamine oxide and the composition may comprise from 50 ppm to 250 ppm 2-ethylhexyl sulfate. The composition may comprise from 100 to 400 ppm lauryldimethylamine oxide and the composition may comprise from 50 to 100 ppm 2-ethylhexyl sulfate.

The composition may comprise additional components. The composition may se a salt.

For example, the composition may comprise an alkali metal salt, such as an alkali metal halide, or sulfate; or an alkali earth metal, such as an alkali earth metal halide or e.

The ition may comprise enzymes such as proteases, lipases, or proteolytic enzymes.

The composition may comprise stabilisers such as polypropylene glycol, glycerin, glycerol, polyols, sorbitols, or sugar alcohols for e.

The composition may be acidic. For example, the composition may have a pH of less than pH 5, less than pH 4, less than pH 3. The composition may have a pH between 0 and 5, 0 and 4, or 0 and 3. The composition may have a pH between 1 and 5, 1 and 4, or 1 and 3.

The composition may be alkaline. For example, the composition may have a pH of more than pH 8, more than pH 9, or more than pH 10. The composition may have a pH from 8 to 14, 9 to 14, or 10 to 14. The composition may have a pH from 8 to 12, 9 to 12, or 10 to 12.

The composition may be neutral. For example, the composition may have a pH from 6 to 8, such as pH 6, pH 6.5, pH 7, pH 7.5 or pH 8.

The composition may be neutral and the pH may be changed before application to a membrane to be cleaned. For example, the pH may be raised prior to application to a membrane to be cleaned. Alternatively, the pH may be lowered prior to ation to a membrane to be cleaned.

Typically, the membrane cleaned using the composition is a polymeric membrane. For example, the membrane may comprise ide, polyether sulfone, polysulfone, polyvinyldifluoride, polypropylene, or polyacrylnitrile. ln alternative embodiments, the membrane that is cleaned using the composition may be a ceramic membrane.

The membrane may comprise a backing layer. The backing layer may be a polymeric backing layer. For example, the backing layer may se polyethylene or polypropylene. al Greups Hale The term "halogen" (or "heio") es fluorine, chlorine, e, and .

Alkyl, alkyiene, alkenwj alkynyi, cycioaikyi etc.

The terms "alkyl", "alkylene , alkenyl", or "elkynyl" are used herein to refer to bath straight and ed chain acyclic forms. Cyclic analogues f are referred tea as cycloalkyl, etc.

The term "alkyl" includes monovaient, straight or branched, saturated, acyclic hydrocarbyl groups. in one embodiment alkyi is C-riealkyl, in another embodiment Ct-SaikYE, in another embcdiment C1.4alkyl, such as methyl, ethyi, n-propyl, l-propyl, or t—butyl groups.

The term "oycloalkyl" includes mohovalent, saturated, cyclic hydrocerbyi groups. in some embodiments the cycloalkyl is cycloalkyl, in other embodiments C3.scycloelkyl, such as cyclobentyl and oyclohexyi.

Substitoente Optionally substituted groups of the compounds of the invention may be substituted or unsubstituted, in one embodiment unsubstituted, Typically, substitution involves the notional ement of a hydrogen atom with a substituent group, or two hydrogen atoms in the case of substitution by :0.

Where substituted, there will generally be 1 to 3 sobetituente unless otherwise stated herein, in one embodiment t or 2 substituents, for example, i tuent.

The optional substituenfls) may be selected independently from the groups ooneisting of halogen, trihalomethyl, trihaloethyl, OH, NHz, "N02, (LN, —N+(Cq.5eikyi)20‘, "COZH, 6020,, saikyl, '803H, —SQCimeaIkyl, —SO2Ci~ealkyi, ~SOst31.ealkyl, )031—ealkyl, —C(=O)H, —C(=O)Cl.seikyi, -OC(=O)C-l.galkyl, =0, —N(C-a.5atkyl)2, ~C(=O)Nl-ia, 'C(=O)N(C1. aalkyl); i.salkyl)C(=O)O(C1.ealkyl), -N(C--,,saikyl)C(=O)N(Ci—emitting, —OC(=Q)N(Ci.eaikyi)2, "N(C1~63|kyDC(:O)C1.GaEk}/E, "C(=S)N(Ci.aalkyl)2, —N{C<..ealkyl)C(=S)Ci.ealkyl, -SO.2N(C31_ selkyip, —l\l(01.5aikyi)SOZC1.salkyi, —N(Ci.aalkyl)C(=S)N(Cl.salkyl)2, ~N(01.5)802N(C1.6eikyi)2, — Ci.saikyl, -Ci.sheteroali According to a second aspect of the invention there is provided a method of cleaning a membrane sing the steps: a) providing a ng composition according to the first aspect; b) applying the ition to a membrane; and c) rinsing the ne to remove the majority of the composition from the membrane; wherein the membrane comprises less than 50 mgi’m2 of the cleaning composition after the step of rinsing the membrane.

Preferably, the membrane is rinsed with water. The membrane may be rinsed with water of high, medium, or low quality.

The membrane may comprise less than 20 mg/m2 of the surfactant after the step of rinsing the membrane. Preferably, the membrane comprises less than 10 mg/m2 of the surfactant after the step of rinsing the membrane. More preferably, the membrane comprises less than mg/m2 of the surfactant after the step of rinsing the membrane. Accordingly, step (c) may remove substantially all of the surfactants of the composition from the membrane. Step (c) may remove substantially all of the composition from the membrane.

In some embodiments, the membrane may retain 50% less amine oxide than compositions sing an amine oxide that do not comprise an alkyl sulfate. The ne may retain 75% less amine oxide than compositions comprising an amine oxide that do not comprise an alkyl sulfate. The membrane may retain 90% less amine oxide than compositions comprising an amine oxide that do not se an alkyl sulfate.

Typically, step (c) es a lower volume of water to remove the cleaning composition from the membrane than methods using ng compositions known in the art. As a result, the down time between production runs where the cleaning composition of the invention is used to clean the membranes is reduced. 1111 The method of the present aspect may be applied to clean membranes that are used to process food or ge products. Accordingly, the method may be applied to clean membranes used to process beer. Alternatively, the method may be d to clean membranes used to process dairy products. In embodiments where the method is used to clean membranes used to process dairy products, the cleaning composition may be particularly efficacious at removing components of the dairy products from the membrane. For example, the cleaning composition may remove milk proteins and fats such as butterfat from the membrane.

The composition may be . For example, the composition may have a pH of less than pH 5, less than pH 4, or less than pH 3.

The composition may be alkaline. The composition may have a pH of more than pH 8, more than pH 9, or more than pH 10. For example, the composition may have a pH of 10, 11, or 12.

The pH of the composition may be changed before being applied to the ne using the method of the invention. The pH of the composition may be raised. For example, the pH of the ition may be raised to pH 8, pH 9, pH 10, or . The pH of the composition may be lowered. For example, the pH of the composition may be lowered to pH 7, pH 5, pH 4, pH 3, or lower.

In a third aspect of the invention, the invention extends to use of a composition according to the first aspect of the invention to clean membranes used to process food products.

Preferred and al features of the first and second aspects are preferred and optional features of the third aspect.

Brief Description of the Figures Embodiments of the present invention will now be described, by way of non-limiting example, with reference to the accompanying drawings.

Figure 1 is a chart showing the cleaning performance of test ng itions and surfactant residue remaining on a membrane cleaned using the compositions. 1212 Detailed Description While the making and using of s embodiments of the present ion are discussed in detail below, it should be appreciated that the present invention es many applicable inventive concepts that can be embodied in a wide variety of specific contexts. The specific ments discussed herein are merely illustrative of specific ways to make and use the invention and do not delimit the scope of the invention.

To facilitate the understanding of this invention, a number of terms are defined below. Terms defined herein have meanings as ly understood by a person of ordinary skill in the areas relevant to the present invention. Terms such as "a", "an", and "the" are not intended to refer to only a singular entity, but include the general class of which a specific example may be used for illustration. The terminology herein is used to describe specific embodiments of the ion, but their usage does not delimit the invention, except as outlined in the claims.

The behaviour of a number of tants on a porous structure such as a membrane was tested on common ultrafiltration membranes as follows.

Method Different types of commercially available polymeric ultrafiltration membranes were tested.

Membrane materials: PES: polyether sulfone, PS: polysulfone. Membrane backing material: PE: polyethylene, PP: opylene. For example, the HFK 131 membrane has a polyether sulfone membrane with a polyethylene backing material this is indicated in table 1 below as PES/PE.

Pre-c/eaning of membranes Membranes were pre-rinsed with deionised water (DI water) at 2m3/hour for 5 minutes at standard conditions (room temperature and 1 bar re). The membranes were then cleaned using citric acid (pH 2.5) for 20 minutes at 40°C, before being rinsed in DI water for minutes. The nes were further cleaned using sodium hydroxide (NaOH) at pH 11.5 for 20 minutes at 40-45°C.

Before and after each stage of cleaning of the membrane, the pure water flux was determined to monitor the tration of any contaminants on the membranes Surfactant Screening 1313 1000 ppm active surfactant solution (in DI water) was ulated at 40-45 °C, 2 bars, in alkaline conditions pH 11.5 at a feed flow of 5 m3/h, through 0.15 mZ/membrane type for 30 s on pre-cleaned and conditioned ultrafiltration membranes (by the process described above).

One tant (sodium 2—ethylhexyl sulfate) was tested in both ne and acidic conditions (pH 2.5).

Any residue on the nes was extracted with acetonitrile at 80°C, 100 bars with Accelerated Solvent Extraction (ASE) in two cycles. The resulting solution was analyzed by liquid chromatography to determine the surfactant concentration extracted from the membrane surface.

The membranes were then rinsed in DI water for 10 minutes at 2m3/hour and 1 bar. Samples were taken every minute from concentrate and total permeate side for surface tension measurements. Again, pure water flux was determined as previously described. The cleaned membranes were then analysed to determine the mass of surfactant residue that remained on the membrane after the above cleaning procedure.

The results of a variety of different commercially available surfactants and surfactant blends tested on membranes with a porous ure are shown below in Table 1.

--IIIIIIICleaning A C E F G --lllllllMembrane Polymer --ll"ll10 3 "mam-- Table 1: y of test results g the residue remaining on test membranes in mg/mz.

Where blends of surfactants were used, xfy gives the residue of surfactant X and surfactant Y respectively. Concentrations of surfactants are 1000ppm unless otherwise stated below. 1414 A is 2—propylheptanol ethoxylates (10M ethylene oxide).

B is lauryldimethylamine oxide C is alkylbenzene sulfonate sodium salt (Cm-C14) D is sodium 2—ethylhexyl e, acidic E is sodium 2—ethylhexyl sulfate, ne F is sodium 2—ethylhexyl sulfate, alkaline 300 ppm + lauryldimethylamine oxide 100 ppm G is sodium 2—ethylhexyl sulfate, alkaline 50 ppm + lauryldimethylamine oxide 100 ppm As can be seen from the results in Table 1, ABS had a superior residue performance (Le, a lower mass of surfactant ed on the membrane after cleaning) compared to lauryldimethylamine oxide. On the other hand, 2-propylheptanol ethoxylates lead to a significantly higher surfactant e than these standard membrane cleaning surfactants (~ factor of 2).

The backing als of the membranes has also been shown to produce different results (compare GR61 PP with GR7OPE, for example).

Cleaning performance versus surfactant residue Whilst a low surfactant residue is important for membrane cleaning itions, it is also important that the cleaning performance of the cleaning composition is of a high standard.

Accordingly, tests were carried out to determine the cleaning performance of a number of cleaning compositions and compared this result with the surfactant residue that remained on a membrane that was cleaned using those compositions.

The cleaning performance of the test cleaning compositions was determined by measuring the percentage of butterfat d from a membrane and was carried out using the following method: PS coupons were prepared by pre-cleaning in methanol for 30 seconds and being d to dry. The coupons were then weighed to get the clean coupon weight. A homogenous layer of butter was applied to the coupons and the dried weight recorded.

Surfactant solutions were prepared and heated to 45°C. The surfactant solutions were stirred at 240rpm and the pH was t to pH 11 using NaOH. The coupons were ded in the surfactant solutions for ten minutes, before being rinsed with deionised 1515 water and d to dry ght. The coupons were then weighed to record the weight of butter that had been removed by the surfactant solution.

The results are shown in Figure 1. The surfactant residue on the membrane cleaned using the compositions is shown normalised to the residue of lauryldimethylamine oxide, a common surfactant used in the art to clean membranes.

As can be seen, lauryldimethylamine oxide showed good cleaning performance, removing 50% of the butterfat from the membrane, but there remained a high e of the surfactant on the ne after rinsing of the membrane.

In contrast, alkylbenzene ate sodium salt (ABS) showed a reduced cleaning performance and an improved residue performance compared to NPE and the amine oxide composition. The sodium 2-ethylhexyl sulfate composition showed very good residue performance but poor cleaning performance.

Surprisingly, the cleaning composition comprising the combination of the lauryldimethylamine oxide and the sodium lhexyl sulfate maintained a similar, if slightly reduced, cleaning performance to the amine oxide alone, whilst also maintaining the good residue performance of the sodium 2-ethylhexyl sulfate composition. ative pure water flux impact studies (data not shown) also showed that lauryldimethylamine oxide had the highest pure water flux impact of rd commercially available surfactants used for ne cleaning, and surprisingly, the addition of an alkyl sulfate such as sodium 2-ethylhexyl sulfate to the lauryldimethylamine oxide did not have a negative impact of the pure water flux impact of the composition. This is a further demonstration of the surprising retention of the superior cleaning performance of the amine oxide even when combined with alkyl sulfate.

The reduction in residue performance was further studied in relation to the volume of water used to rinse a membrane. Table 2 below shows a comparison of the residue remaining on a membrane, as measured by the surface n of the rinse water runoff, for lauryldimethylamine oxide (AO) alone and lauryldimethylamine oxide in combination with sodium 2-ethylhexyl sulfate (AS). 1616 AO+AS Rinse Volume [I] Surface tension [Nlm] e tension [Nlm] 4000 30.1 26.2 8000 30.8 12000 . 52.7 16000 60.7 20000 . 61.3 Table 2: Surface tension of rinse water that has been used to rinse a membrane cleaned using with a cleaning composition comprising lauryldimethylamine oxide (AO) compared to a membrane cleaned using a ng composition comprising lauryldimethylamine oxide and sodium 2-ethylhexyl sulfate (AS).

As can be seen, the combination ition is removed at a faster rate than the composition comprising the lauryldimethylamine oxide only.

In further studies, it was shown that the ng performance of the lauryldimethylamine oxide was largely unaffected by the concentration of sodium lhexyl sulfate.

In contrast, other cleaning compositions comprising a blend of surfactants that were , such as a ition comprising lauryldimethylamine oxide and oleic acid sulfonate potassium salt, showed that the cleaning performance of the amine oxide decreased proportionally to the concentration of the oleic acid sulfonate potassium salt.

Accordingly, the composition comprising the combination of lauryldimethylamine oxide and sodium 2-ethylhexyl sulfate was found to be surprisingly efficacious for use as a cleaning composition for membranes, especially those membranes used to process food products such as dairy products.

Claims (12)

WE CLAIM :

1. A membrane cleaning composition comprising at least one amine oxide and at least one alkyl sulfate, wherein the at least one alkyl sulfate comprises 2-ethylhexyl e and the at least one amine oxide comprises lauryldimethylamine oxide.

2. A membrane cleaning composition according to claim 1, wherein the membrane cleaning composition comprises a plurality of amine oxides.

3. A membrane cleaning composition according to claim 1 or 2, wherein the membrane cleaning composition comprises from 100 ppm to 500 ppm lauryldimethylamine oxide and from 50 ppm to 250 ppm 2-ethyl hexyl sulfate.

4. A membrane cleaning composition according to any one of claims 1 to 3, wherein the membrane cleaning composition has a pH of more than 8.

5. A method of cleaning a membrane comprising the steps: a) providing a membrane cleaning ition according to any one of claims 1 to 4; b) applying the membrane cleaning composition to a membrane; and c) rinsing the membrane to remove at least a ty of the composition from the membrane; wherein the ne comprises less than 50 mg/m2 of the cleaning composition after the step of rinsing the membrane.

6. A method according to claim 5, wherein the ne ses less than 20 mg/m2 of the cleaning ition after the step of rinsing the membrane.

7. A method according to claim 5 or claim 6, wherein the membrane is used to process a food product or beverage.

8. A method according to claim 7, n the membrane is used to process a dairy product, fruit juice or alcoholic ge.

9. A method ing to any one or claims 5 to 8, wherein the membrane is a polymeric membrane.

10. A method according to claim 9, wherein the membrane comprises polyamide, polyether sulfone, polysulfone, polyvinyldifluoride, polypropylene, or polyacrylnitrile.

11. A method according to any one of claims 5 to 10, wherein the membrane comprises a polymeric backing layer.

12. Use of a membrane ng composition according to any one of claims 1 to 4 to clean a membrane used to process a food product. Ecolab USA Inc. By the Attorneys for the ant SPRUSON & FERGUSON Per: