Rinse aid composition

Abstract

A rinse aid composition comprising a surfactant mixture comprising (i) a compound (a) and a compound (b), (ii) a compound (a) and a compound (c), or (iii) a compound (b) and a compound (c), where compound (a) is an ethoxylated and propoxylated C11 to C16 linear or branched alcohol, compound (b) is an ethoxylated and propoxylated C6 to C9 linear or branched alcohol, compound (c) is an ethoxylated and propoxylated C12 to C16 linear or branched alcohol, and wherein the rinse aid composition comprises at least 10 wt.% surfactant mixture, based on the total weight of the rinse aid composition, and when the surfactant mixture includes a compound (a) and a compound (c), the rinse aid composition contains at least 70 ppm of active surfactant.

Description

[0001] RINSE AID COMPOSITION

[0002] TECHNICAL FIELD

[0003] The present invention is directed to new rinse aid compositions, and in particular, to new rinse aid compositions that enable faster drying of wares.

[0004] BACKGROUND

[0005] Auto dishwash operations are growing rapidly across various sectors, e.g., in the hospitality and quick service restaurant (QSR) industries, to facilitate serving high numbers of customers in a day. Auto dishwash operation includes washing and rinsing as two key steps. While cleaning of the wares is an obvious necessity, drying is equally important when it comes to the number of usage cycles for the wares. To aid with drying, rinse aids are used in auto dishwash operation to remove excess water from the surface and make the wares dry. Surfactants present in the rinse aid lower the surface tension of the final rinsing water which leads to improved wetting on the surface of the ware. This prevents droplet formation, and because the water sheets off the surface in a thin layer, drying times are also reduced.

[0006] Single-use plastic pollution is a worry due to recent regulations and increased environmental awareness, which encourages the use of reusable plastic materials. Polycarbonate, polypropylene, polyethylene, high density polyethylene, polyethylene terephthalate, Tritan, melamine, and polyamide are widely used materials of reusable plastic wares due to their light weight, easy handling, and no breakage. However, due to having a lower surface energy (18- 50 dynes / cm), these plastic materials take longer to dry than conventional porcelain, stainless steel, glass, and ceramic wares in auto dishwash operation. Even with use of high dosages of rinse aids, reusable plastic wares can take 15-30 minutes to air dry.

[0007] This slow drying makes the auto dishwash operation time consuming and laborious. To overcome this challenge, electrically heated dryers have been used together with high dosages of rinse aid (as high as 50% over the recommended dosages). This significantly increases the cost and energy consumption of the auto dishwash operation. To successfully shorten the drying time for reusable plastic wares while maintaining other advantageous features, such as spotless appearance, a new generation of rinse aid is needed.

[0008] SUMMARY OF DISCLOSURE

[0009] The present invention is directed to a rinse aid composition comprising a surfactant mixture comprising:

[0010] (i) a compound (a) and a compound (b),

[0011] (ii) a compound (a) and a compound (c), or

[0012] (iii) a compound (b) and a compound (c), where: compound (a) is an ethoxylated and propoxylated Cii to Ci6 linear or branched alcohol, compound (b) is an ethoxylated and propoxylated G> to C9 linear or branched alcohol, compound (c) is an ethoxylated and propoxylated C12 to Ci6 linear or branched alcohol, the rinse aid composition comprises at least 10 wt.% surfactant mixture, based on the total weight of the rinse aid composition, and when the surfactant mixture includes a compound (a) and a compound (c), the rinse aid composition contains at least 70 ppm of active surfactant.

[0013] Advantageously, such a rinse aid composition has been found to deliver excellent drying performance in reusable plastic ware, significantly reducing drying times from 15-30 minutes (for example, to less than 5 minutes), without the use of electrically heated dryers.

[0014] In particular, the specific nonionic surfactant mixtures disclosed have been found to reduce the surface tension of the final rinsing water to be close to the surface energy of the reusable plastic ware, therefore obtaining the desired sheeting effect and faster water evaporation in accordance with the equation:

[0015] Spreading coefficient = A - ( B + C )

[0016] Where:

[0017] A = Surface energy of solid. B = Surface tension of liquid. C = Surface energy of solid-liquid interface. And, if the spreading coefficient is: Negative - bidding effect will happen. Zero to Positive - the liquid will spread.

[0018] The invention is also directed to a method for rinsing ware in a ware washing application and to using the rinse aid composition.

[0019] DETAILED DESCRIPTION

[0020] The various aspects of the present invention will be elucidated further below.

[0021] As indicated above, in a first aspect, the present invention provides a rinse aid composition comprising a surfactant mixture comprising:

[0022] (i) a compound (a) and a compound (b),

[0023] (ii) a compound (a) and a compound (c), or

[0024] (iii) a compound (b) and a compound (c), where: compound (a) is an ethoxylated and propoxylated Cn to Ci6 linear or branched alcohol, compound (b) is an ethoxylated and propoxylated G, to C9 linear or branched alcohol, compound (c) is an ethoxylated and propoxylated C12 to Ci6 linear or branched alcohol, the rinse aid composition comprises at least 10 wt.% surfactant mixture, based on the total weight of the rinse aid composition, and when the surfactant mixture includes a compound (a) and a compound (c), the rinse aid composition contains at least 70 ppm of active surfactant.

[0025] In a first embodiment (i), the surfactant mixture comprises, consists essentially of, or consists of a compound (a) (i.e., an ethoxylated and propoxylated C11 to Ci6 linear or branched alcohol) and a compound (b) (i.e., an ethoxylated and propoxylated Ce to C9 linear or branched alcohol). In this embodiment, the rinse aid composition may contain from 30 ppm to 700 ppm of active surfactant, preferably from 70 ppm to 600 ppm of active surfactant, and more preferably from 100 to 500 ppm of active surfactant.

[0026] For the avoidance of doubt, the term “consists of’ is used herein to exclude any additional elements, while the term “consists essentially of’ permits additional elements that do not materially affect characteristics of the surfactant mixture. For example, the surfactant mixture consisting essentially of the two nonionic surfactants (a) and (b) excludes any additional surfactants but may further include preservatives, impurities, or solvents, such as water, lower Ci- C4 alcohols, glycols, or glycol ethers.

[0027] In a second embodiment (ii), the surfactant mixture comprises, consists essentially of, or consists of a compound (a) (i.e., an ethoxylated and propoxylated Cn to C16 linear or branched alcohol) and a compound (c) (i.e., an ethoxylated and propoxylated C 12 to Ci6 linear or branched alcohol). In this embodiment, the rinse aid composition may contain from 70 ppm to 700 ppm of active surfactant, preferably from 80 ppm to 600 ppm of active surfactant, and more preferably from 100 to 500 ppm of active surfactant. For the avoidance of doubt, it is noted that compound (a) and compound (c) are different.

[0028] In a third embodiment (iii), the surfactant mixture comprises, consists essentially of, or consists of a compound (b) (i.e., an ethoxylated and propoxylated Ce to C9 linear or branched alcohol) and a compound (c) (i.e., an ethoxylated and propoxylated C12 to Ci6 linear or branched alcohol). In this embodiment, the rinse aid composition may contain from 30 ppm to 700 ppm of active surfactant, preferably from 70 ppm to 600 ppm of active surfactant, and more preferably from 100 to 500 ppm of active surfactant.

[0029] The surfactant mixture of embodiments (i), (ii) and (iii) may be substantially free of ethoxylated alcohols, for example, those having the structure R’-O-(EO)P-H, where R’ is a Ci-Cis linear or branched alkyl and p is from 1-100. Additionally, or alternatively, the surfactant mixture of embodiments (i), (ii) and (iii) may be substantially free of butoxylated alcohols, for example, those having the structure R”-O-(BO)q-H, where R” is a Ci-Cis linear or branched alkyl and q is from 1-100. As used herein, the phrase "substantially free" means a concentration of less than 10 ppm, preferably less than 1 ppm.

[0030] Compound (a) is an ethoxylated and propoxylated Cn to C16 linear or branched alcohol. Preferably, compound (a) is an ethoxylated and propoxylated Cn to C15 branched alcohol, more preferably an ethoxylated and propoxylated C12 to C14 branched alcohol, and most preferably an ethoxylated and propoxylated C13 branched alcohol. That is, compound (a) may be a poly oxy alkylene condensate surfactant having the structure represented by formula (I):

[0031] R]-O-[(EO)m-(PO)n]x formula (I) where R1is monoisotridecyl; m is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29; n is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29; and x is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29 and the EO and PO units may be random, alternating, block, or graft, preferably block.

[0032] Exemplary ethoxylated and propoxylated Cn to Ci6 linear or branched alcohols suitable for use as compound (a) in the rinse aid composition include but are not limited to methyl-oxirane polymers with alkyl ether oxirane block surfactants. Exemplary methyl-oxirane polymers with alkyl ether oxirane block surfactants include methyl-oxirane polymer with hexadecyl ether block, and / or methyl-oxirane polymer with monoisotridecyl ether oxirane block (CAS No. 196823-11- 7).

[0033] Compound (b) is an ethoxylated and propoxylated Ce to Cj linear or branched alcohol. Preferably, compound (b) is an ethoxylated and propoxylated C7 to C9 branched alcohol, more preferably an ethoxylated and propoxylated Cs to C9 branched alcohol, and most preferably an ethoxylated and propoxylated Cs branched alcohol. That is, compound (b) may be a polyoxyalkylene condensate surfactant having the structure represented by formula (II):

[0034] R2-O-[(EO)m-(PO)n]x formula (II) where R2is 2-ethyl-l -hexyl; m is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29; n is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29; and x is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29 and the EO and PO units may be random, alternating, block, or graft.

[0035] An exemplary ethoxylated and propoxylated Ce to C9 linear or branched alcohol suitable for use as compound (b) is the methyl-oxirane polymer with mono(2-ethylhexyl) ether oxirane (CAS No. 64366-70-7).

[0036] Compound (c) is an ethoxylated and propoxylated C12 to Cie linear or branched alcohol. Preferably, compound (c) is an ethoxylated and propoxylated C12 to Cie linear alcohol, more preferably an ethoxylated and propoxylated C12 to C14 linear alcohol. That is, compound (c) may be a polyoxyalkylene condensate surfactant having the structure represented by formula (III): R3-O-[(EO)m-(PO)n]; formula (III) where R3is selected from n-dodecane, n-tridecane, n-tetradecane, or mixtures thereof; m is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29; n is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29; and x is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29 and the EO and PO units may be random, alternating, block, or graft.

[0037] Exemplary ethoxylated and propoxylated C12 to Ci6 linear or branched alcohols suitable for use as compound (c) is the mixture of ethoxylated and propoxylated C12-C14 alcohols (CAS No. 68439-51-0).

[0038] The rinse aid composition comprises at least 10 wt.% surfactant mixture, based on the total weight of the rinse aid composition. Preferably, the rinse aid composition comprises from 20 to 60 wt.% surfactant mixture, preferably from 25 to 50 wt.% surfactant mixture, more preferably from 30 to 40 wt.% surfactant mixture, based on the total weight of the rinse aid composition.

[0039] In the first embodiment (i), the weight ratio of compound (a):compound (b) may range from 20:1 to 1:8. At these ratios, a synergistic drying effect is obtained. For optimal synergy, the weight ratio of compound (a) compound (b) may range from 10:1 to 1:7, preferably from 4: 1 to 1.5: 1 or from 1: 1.5 to 1 :2.5.

[0040] In the second embodiment (ii), the weight ratio of compound (a):compound (c) may range from 8:1 to 1: 10. At these ratios, a synergistic drying effect is obtained. For optimal synergy, the weight ratio of compound (a):compound (c) may range from 8:1 to 1:4.5, preferably from 4.5: 1 to 1.5:1 or from 1:1.5 to 1:2.5.

[0041] In the third embodiment (iii), the weight ratio of compound (b) compound (c) may range from 20: 1 to 1:20. At these ratios, a synergistic drying effect is obtained. For optimal synergy, the weight ratio of compound (b):compound (c) may range from 4:1 to 1 :8, preferably from 2.5:1 to 1.5:1 or from 1:1.5 to 1:3.5.

[0042] The rinse aid composition may include a number of additional additives and / or functional materials. For example, the rinse aid composition may additionally include carriers, hydroptropes, microbial controlling agent, and / or pH adjusting agents. The rinse aid composition is typically formulated as a liquid composition, preferably a single phase liquid composition. Carriers can be included in such liquid formulations. Any carrier suitable for use in a rinse aid composition can be used in the present invention. For example, the composition may include water as a carrier. When water is included as a carrier, the liquid rinse aid composition will contain no more than 98 wt.% water and typically no more than 90 wt.%. Likewise, the liquid rinse aid composition will contain at least 50 wt.% water, or at least 60 wt.% water as a carrier.

[0043] The rinse aid composition may include at least one hydrotrope. Hydrotropes are similar to surfactants, in that they have a hydrophilic part and a hydrophobic part. However, the hydrophobic part of a hydrotrope is too small to cause spontaneous self-aggregation associated with surfactant. As a result, hydrotropes do not exhibit a crucial micelle concentration (cmc) or a critical vesicle concentration (esc) associated with surfactant activity. Exemplary hydrotropes include urea, tosylate, cumene sulfonate, and xylene sulfonate. Preferably, the hydrotrope is sodium cumene sulfonate or sodium xylene sulfonate.

[0044] A hydrotrope or a combination of hydrotropes may be present in the rinse aid composition in an amount of from 1 to 10 wt.%, based on the total weight of the rinse aid composition. Preferably the rinse aid composition contains at least one hydrotrope in an amount of from 1 wt.% to 5 wt.%, more preferably 1.5 to 2.5 wt.%, based on the total weight of the rinse aid composition.

[0045] The rinse aid composition may include at least one microbial controlling agent. Microbial controlling agents are chemical compounds that can be used in a functional material to prevent microbial contamination and deterioration of material systems, surfaces, etc. A microbial controlling agent, depending on chemical composition and concentration, may simply limit further proliferation of numbers of the microbe or may destroy all or a portion of the microbial population. The terms "microbes" and "microorganisms" typically refer primarily to bacteria, virus, yeast, spores, and fungus microorganisms.

[0046] Preferred microbial controlling agents for use in the rinse aid compositions of the present invention include sodium benzoate, sodium formate, benzyl alcohol, formic acid, potassium sorbate, isothiazolinones such as 5-chloro-2-methyl-4-isothiazolin-3-one and / or 2-methyl-4- isothiazolin-3-one, or any combination thereof. The at least one microbial controlling agent can be included in the rinse aid composition in an amount of from 0.01 to 2.0 wt.%, based on the total weight of the composition. Preferably, the at least one microbial controlling agent is included in the rinse aid composition in an amount of from 0.05 to 1.0 wt.%, based on the total weight of the composition, more preferably from 0.1 to 0.75 wt.%, and most preferably from 0.25 to 0.5 wt.%.

[0047] The rinse aid composition may further include a pH adjuster to maintain the pH of the formulation between 2 and 8, preferably between 4.5 and 7.5, more preferably between 5 and 7. Exemplary pH adjusters include acids, such as HC1, H2SO4, citric acid, lactic acid, sorbic acid, acetic acid, boric acid, formic acid, maleic acid, adipic acid, malic acid, malonic acid, glycolic acid, alkyl sulfonic acid (e.g., methane sulfonic acid), and mixtures thereof. Preferably, the pH adjuster has a pKa of approximately 3, such as acetic acid, ascorbic acid, benzoic acid, citric acid, or formic acid. Alternatively, the pH adjuster may be a buffer, such as citric acid and NazHPCE, citric acid and sodium citrate, sodium acetate and acetic acid, or combinations thereof.

[0048] Preferably, citric acid is used as the pH adjuster. Citric acid may be included in the rinse aid composition in an amount of from 0.01 to 4.0 wt.%, preferably from 0.05 to 2.0 wt.%, based on the total weight of the rinse aid composition. Preferably, citric acid is included in the rinse aid composition in an amount of from 0.05 to 1.5 wt.%, based on the total weight of the composition, more preferably from 0.1 to 1 wt.%.

[0049] The disclosed liquid rinse aid formulations may be prepared by: adding a predetermined amount of the nonionic surfactants to demineralized water, under stirring, and stirring until the mixture is homogeneous, adding a predetermined amount of additional additives (e.g., a hydrotrope, a microbial controlling agent and a pH adjuster), under stirring, and stirring until the mixture is clear and homogenous, stirring the resulting mixture for a further 15 minutes, while maintaining the temperature below 40 °C.

[0050] The rinse aid composition as described above can be used in various applications, including, dish washing, crate washing, chocolate mold washing, reactor vessel cleaning (e.g., in pharmaceutical manufacturing), cleaning-in-place (CIP) systems, Open Plant Cleaning (OPC), automotive parts cleaning, and solar panel cleaning.

[0051] In a second aspect, the present invention provides a method for rinsing ware in a ware washing application comprising:

[0052] I. providing a rinse aid composition of the first aspect; and

[0053] II. applying the rinse aid composition to the ware.

[0054] The rinse aid composition may contain from 70 ppm to 700 ppm of active surfactant, preferably from 100 to 500 ppm of active surfactant.

[0055] As used herein, and as in the commercial dishwashing industry, the term "ware" may refer to reusable items that require cleaning in food service, healthcare and hospitality operations. This includes dishes, glassware, cookware, utensils, trays, and other kitchen tools such as mixers, blenders or serving pieces used in the preparation, service, or consumption of food and beverages. Reusable plastic wares, such as plastic trays, cups, bowls, tumblers, containers, and cutlery, are also included in this category, especially in institutions like schools, hospitals, flight catering and cafeterias, where lightweight and durable materials are preferred.

[0056] When the ware is a reusable plastic ware it may be made, for example, from polycarbonate, polypropylene, polyethylene, high density polyethylene, polyethylene terephthalate, Tritan, melamine, or polyamide.

[0057] The rinsing may be performed at a temperature of from 50 to 85°C. To effectively sanitize the ware through heat, the final rinse cycle must typically reach a temperature between 80-85°C. Alternatively, a chemical sanitizer can be used, and the rinse water can be maintained between 50-60°C to optimize the effectiveness of the sanitizing agent. This low-temperature rinsing is suitable for establishments where hot water availability is limited or where energy efficiency is a priority.

[0058] It is noted that various elements of the present invention, including but not limited to preferred ranges for the various parameters, can be combined unless they are mutually exclusive. The invention will be elucidated by the following examples without being limited thereto or thereby.

[0059] Examples

[0060] The surfactants used in the following examples are as follows:

[0061] Surfactant (a) ethoxylated and propoxylated C13 branched alcohol (CAS No. 196823-1 1-7)

[0062] Surfactant (b) ethoxylated and propoxylated Cs branched alcohol (CAS No. 64366-70-7)

[0063] Surfactant (c) ethoxylated and propoxylated C12-C14 linear alcohols (CAS No. 68439-51-0)

[0064] Existing commercial rinse aid products used in the following examples are as follows:

[0065] Comparative rinse aid I - containing ethoxylated and butoxylated C13-C15 branched and linear alcohols and poly(ethylene glycol-ran-propylene glycol) monobutyl ether.

[0066] Comparative rinse aid II - containing ethoxylated and butoxylated C13-C15 branched and linear alcohols.

[0067] Comparative rinse aid III - containing ethoxylated and propoxylated C10 branched alcohol, ethoxylated and propoxylated C12-C14 linear alcohols and ethoxylated C13 branched alcohol.

[0068] Comparative rinse aid IV - containing ethoxylated and propoxylated C12-C14 linear alcohols and polyethylene glycol-ran-propylene glycol) monobutyl ether.

[0069] Drying performance test

[0070] In an effort to mimic the circumstances present in commercial dishwash operations, a novel method for measuring the drying performance was developed. In this method the drying time of a rinse aid composition was measured by loss of water with time post-rinse cycle in dishwash operation.

[0071] A polypropylene cup was selected as representative plastic ware as these wares are difficult to dry due to their lower surface energy (~30 dyne / cm).

[0072] After washing in an auto dishwasher, the weight of residual water on the ware was measured on a weighing balance (accuracy limit: 0.001g; set up so that water droplets could not fall on the weighing panel). 0.2 g of residual water was considered as the endpoint for drying of the ware (after visual observation) to mimic real condition in commercial dishwash operation.

[0073] All experiments were conducted on Meiko DV 80.2 single tank hood type auto dishwasher. A wash time of 110 seconds, a rinse time of 10 seconds, and a rinse volume of 3 L was used.

[0074] The following are the specifications for the single tank hood dishwasher.

[0075] Wash tank capacity: 22 L.

[0076] Rinse tank capacity: 10.5 L.

[0077] Wash temperature: 55-65 °C. Rinse temperature: 75-85 °C.

[0078] Example 1: Drying performance of new rinse aid compositions compared to no or existing commercial rinse aids

[0079] Rinse aid compositions 1.1, 1.2, 1.3 and 1.4 were prepared with the ingredients and quantities (wt.%) shown in Table 1A. Taking the preparation of rinse aid composition 1.4 as an example, 66.5 g of demineralized water was added to a reaction beaker and stirring started. 20 g of surfactant (c) and 10 g of surfactant (b) were then added to the beaker, one after the other in a sequential manner, and the resultant mixture stirred until it became homogeneous. 2 g of sodium cumene sulfonate was then added to the beaker and the mixture stirred until it became homogenous. 0.25 gm of sodium benzoate and 0.25 g of potassium sorbate were then added to the beaker, under stirring, before 1 g of citric acid was added. The mixture was stirred until the citric acid was fully dissolved and the mixture became clear and homogenous again. The resulting mixture was then stirred for 15 minutes while maintaining the temperature below 40°C. After this time, stirring was stopped and the composition transferred into a storage container.

[0080] Table 1A: Rinse aid compositions

[0081] Each composition was tested for its drying performance on a polypropylene cup at a dosage corresponding to 450 ppm of surfactant active concentration. Drying performance was assessed by measuring the weight of water loss with time until 0.2 g of residual water, as described in the drying performance test set out above. The results are shown in Table IB, as compared to existing commercial rinse aid products and to surfactants (a), (b) and (c) alone.

[0082] Table IB: Drying performance of 450 ppm active concentration on polypropylene ware The results show that compositions 1.1, 1.2, 1.3 and 1.4 provide greatly improved drying performance on the polypropylene ware, with each delivering a drying time < 5 minutes.

[0083] Example 2: Effect of ratio of nonionic surfactants (a):(b) on drying performance Rinse aid compositions 2.1 to 2.11 were prepared according to the procedure described in Example 1, with the ingredients and quantities (wt.%) shown in Table 2 A. Table 2A: Rinse aid compositions

[0084] Each composition was tested for its drying performance on a polypropylene cup at a dosage corresponding to 450 ppm of surfactant active concentration. Drying performance was assessed by measuring the weight of water loss with time until 0.2 g of residual water, as described in the drying performance test set out above. The weight of the remaining water on the wares after three minutes was also noted. The results are shown in Table 2B, as compared to surfactants (a) and (b) alone.

[0085] Table 2B: Drying performance of 450 ppm active concentration on polypropylene ware

[0086] The results show a synergistic drying effect when surfactants (a) and (b) are combined in a weight ratio of from 20: 1 to 1:5 (with compositions 2.1 to 2.9 each providing improved drying performance on the polypropylene ware than either surfactant alone). Optimal synergy is obtained in compositions 2.4, 2.5, and 2.7, with these compositions each delivering a drying time of less than 5 minutes. Composition 2.7 is the best performing rinse aid composition since, after three minutes, it leaves the least amount of water on the ware.

[0087] Example 3: Effect of ratio of nonionic surfactants (a):(c) on drying performance

[0088] Rinse aid compositions 3.1 to 3.9 were prepared according to the procedure described in Example 1, with the ingredients and quantities (wt.%) shown in Table 3 A.

[0089] Table 3A: Rinse aid compositions

[0090] Each composition was tested for its drying performance on a polypropylene cup at a dosage corresponding to 450 ppm of surfactant active concentration. Drying performance was assessed by measuring the weight of water loss with time until 0.2 g of residual water, as described in the drying performance test set out above. The weight of the remaining water on the wares after three minutes was also noted. The results are shown in Table 3B, as compared to surfactants (a) and (c) alone.

[0091] Table 3B: Drying performance of 450 ppm active concentration on polypropylene ware

[0092] The results show a synergistic drying effect when surfactants (a) and (c) are combined in a weight ratio of from 5: 1 to 1:10 (with compositions 3.2 to 3.9 each providing improved drying performance on the polypropylene ware than either surfactant alone). Optimal synergy is obtained in compositions 3.3, 3.4 and 3.6, with these compositions each delivering a drying time of 5 minutes or less. Composition 3.3 is the best performing rinse aid composition since, after three minutes, it leaves the least amount of water on the ware. Example 4: Effect of ratio of nonionic surfactants (b):(c) on drying performance

[0093] Rinse aid compositions 4.1 to 4.11 were prepared according to the procedure described in Example 1, with the ingredients and quantities (wt.%) shown in Table 4 A.

[0094] Table 4A: Rinse aid compositions

[0095] Each composition was tested for its drying performance on a polypropylene cup at a dosage corresponding to 450 ppm of surfactant active concentration. Drying performance was assessed by measuring the weight of water loss with time until 0.2 g of residual water, as described in the drying performance test set out above. The weight of the remaining water on the wares after three minutes was also noted. The results are shown in Table 4B, as compared to surfactants (b) and (c) alone. Table 4B: Drying performance of 450 ppm active concentration on polypropylene ware

[0096] The results show a synergistic drying effect when surfactants (b) and (c) are combined in a weight ratio of from 20: 1 to 1 :20 (with compositions 4.1 to 4.11 each providing improved drying performance on the polypropylene ware than either surfactant alone). Optimal synergy is obtained in compositions 4.5, 4.7 and 4.8, with these compositions each delivering a drying time of less than 5 minutes. Composition 4.8 is the best performing rinse aid composition since, after three minutes, it leaves the least amount of water on the ware.

[0097] Whilst the invention has been described with reference to an exemplary embodiment, it will be appreciated that various modifications are possible within the scope of the invention.

[0098] In this specification, unless expressly otherwise indicated, the word ‘or’ is used in the sense of an operator that returns a true value when either or both of the stated conditions is met, as opposed to the operator ‘exclusive or’ which requires that only one of the conditions is met. The word ‘comprising’ is used in the sense of ‘including’ rather than to mean ‘consisting of’. All prior teachings acknowledged above are hereby incorporated by reference. No acknowledgement of any prior published document herein should be taken to be an admission or representation that the teaching thereof was common general knowledge in Europe or elsewhere at the date hereof.

Claims

CLAIMS:

1. A rinse aid composition comprising a surfactant mixture comprising:(i) a compound (a) and a compound (b),(ii) a compound (a) and a compound (c), or(iii) a compound (b) and a compound (c), where: compound (a) is an ethoxylated and propoxylated Cn to Ci6 linear or branched alcohol, compound (b) is an ethoxylated and propoxylated G> to C9 linear or branched alcohol, compound (c) is an ethoxylated and propoxylated C12 to Ci6 linear or branched alcohol, the rinse aid composition comprises at least 10 wt.% surfactant mixture, based on the total weight of the rinse aid composition, and when the surfactant mixture includes a compound (a) and a compound (c), the rinse aid composition contains at least 70 ppm of active surfactant.

2. A rinse aid composition as claimed in claim 1 , wherein compound (a) is an ethoxylated and propoxylated Cn to C15 branched alcohol, preferably an ethoxylated and propoxylated C12 to C14 branched alcohol, and more preferably an ethoxylated and propoxylated C13 branched alcohol.

3. A rinse aid composition as claimed in claim 1 or claim 2, wherein compound (b) is an ethoxylated and propoxylated C7 to C9 branched alcohol, preferably an ethoxylated and propoxylated Cs to C9 branched alcohol, more preferably an ethoxylated and propoxylated Cs branched alcohol.

4. A rinse aid composition as claimed in any preceding claim, wherein compound (c) is an ethoxylated and propoxylated C12 to Ci6 linear alcohol, preferably an ethoxylated and propoxylated C12 to C14 linear alcohol.

5. A rinse aid composition as claimed in any preceding claim, wherein the weight ratio of compound (a):compound (b) ranges from 20:1 to 1:8, preferably from 10: 1 to 1:7, more preferably from 4:1 to 1.5:1 or from 1:1.5 to 1:2.5.

6. A rinse aid composition as claimed in any preceding claim, wherein the weight ratio of compound (a):compound (c) ranges from 8:1 to 1:10, preferably from 8: 1 to 1:4.5, more preferably from 4.5:1 to 1.5: 1 or from 1:1.5 to 1:2.5.

7. A rinse aid composition as claimed in any preceding claim, wherein the weight ratio of compound (b):compound (c) ranges from 20:1 to 1:20, preferably from 4:1 to 1:8, more preferably from 2.5:1 to 1.5: 1 or from 1:1.5 to 1:3.5.

8. A rinse aid composition as claimed in any preceding claim, wherein compound (a) is a polyoxyalkylene condensate surfactant having the structure represented by formula (I):R1-0-[(E0)m-(P0)n]x formula (I) where R1is monoisotridecyl; m is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29; n is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29; and x is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29 and the EO and PO units may be random, alternating, block, or graft, preferably block.

9. A rinse aid composition as claimed in any preceding claim, wherein compound (b) is a polyoxyalkylene condensate surfactant having the structure represented by formula (II):R2-O-[(EO)m-(PO)n]x formula (II) where R2is 2-ethyl-l -hexyl; m is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29; n is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29; and x is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29 and the EO and PO units may be random, alternating, block, or graft.

10. A rinse aid composition as claimed in any preceding claim, wherein compound (c) is a polyoxyalkylene condensate surfactant having the structure represented by formula (III):R3-O-[(EO)m-(PO)n]; formula (III) where R3is selected from n-dodecane, n-tridecane, n-tetradecane, or mixtures thereof; m is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29; n is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29; and x is from 1 to 100, preferably from 1 to 50, more preferably from 1 to 29 and the EO and PO units may be random, alternating, block, or graft.

11. A method for rinsing ware in a ware washing application comprising:I. providing a rinse aid composition as claimed in any one of claims 1 to 10; andII. applying the rinse aid composition to the ware.

12. A method as claimed in claim 11, wherein the rinse aid composition contains from 70 ppm to 700 ppm of active surfactant, preferably from 100 to 500 ppm of active surfactant.

13. A method as claimed in claim 11 or claim 12, wherein the ware is a reusable plastic ware.

14. A method as claimed in claim 13, wherein the ware is made from polycarbonate, polypropylene, polyethylene, high density polyethylene, polyethylene terephthalate, Tritan, melamine, or polyamide.

15. Use of a rinse aid composition as claimed in any one of claims 1 to 10 in dish washing, crate washing, chocolate mold washing, reactor vessel cleaning, cleaning-in-place (CIP) systems, Open Plant Cleaning (OPC), automotive parts cleaning, or solar panel cleaning.

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