Acidic CIP / COP CLEANING COMPOSITION FOR ENHANCED SOIL REMOVAL

Abstract

The present invention relates to an acidic CIP / COP cleaning composition to enhance soil removal. An aqueous acidic cleaning composition comprising at least about 30% of an aqueous solution of active nitric acid; about 20 to 80 wt% of water; and at least one of (A) about 0.01-1% by weight of at least two polyethoxylated fatty alcohols having different molecular masses and / or (B) about 0.01-0.5% by weight of a nonionic glucosamide co-surfactant. Also disclosed are methods of cleaning soil using the cleaning compositions, including enhanced fatty soil removal and organic soil removal (e.g., soap scum). The cleaning compositions of the present invention provide enhanced cleaning effects on metal and other surfaces, particularly stainless steel surfaces.

Description

[0001] This application is a divisional application of the Chinese invention patent application with application number 201811398827.7, application date November 22, 2018, and invention name “Acidic CIP / COP cleaning composition for enhanced dirt removal”. Technical Field

[0002] Concentrated nitric acid cleaning compositions employing the use of ethoxylated fatty alcohols provide stable compositions with enhanced cleaning effects on metal surfaces and other surfaces, particularly stainless steel surfaces. In particular, highly concentrated nitric acid cleaning compositions employing a blend of polyethoxylated fatty alcohols and (in some embodiments) nonionic glucamide surfactants provide enhanced cleaning effects on metal surfaces and other surfaces. Compositions having a blend of at least 30% active nitric acid or preferably at least 40% active nitric acid and a surfactant are advantageously stable formulations. Methods of use are also disclosed, including enhanced fatty soil removal and soap scum removal, particularly for clean-in-place (CIP) applications. Background Art

[0003] Steel is a generic name for a class of ferrous metals, composed primarily of iron, that have remarkable durability and versatility. By appropriate selection of carbon content, addition of alloying elements, and by suitable heat treatment, different types of steel can be made for various purposes, and all types of steel are now widely used in industry. Stainless steel (SS) is a steel alloy that is less susceptible to rust, corrosion, or rust than conventional steel. There are more than 150 different grades and surface finishes to allow stainless steel to be suitable for the environment in which it is used. The low maintenance and low cost of stainless steel make it an ideal base material for many commercial applications, including (for example) kitchenware, hardware, instruments, appliances, industrial equipment, food and beverage processing industrial equipment, and many other surfaces.

[0004] The cleaning of stainless steel includes removing various surface contaminants to ensure corrosion resistance, prevent pollution, and obtain the appearance of the desired steel. Acid cleaning is a process in which an aqueous solution of a mineral acid and / or an organic acid is used together with (sometimes) a wetting agent or a detergent or both to remove contaminants, photo-oxidation films, dirt and similar contaminants of iron and other metals. The acid cleaning composition used to remove contaminants from stainless steel generally has a mineral acid or organic acid in a solution having a pH less than 7.0. The composition can remove organic and inorganic dirt simultaneously in the same operation. They are also used to improve corrosion resistance and enhance the brightness and gloss of the base metal surface.

[0005] Most acid cleaners also include some corrosion inhibitor. For example, copper sulfate has been used as a corrosion inhibitor in acid media. However, these inhibitors are not completely satisfactory because they (such as copper sulfate) can be expensive, introduce wastewater disposal problems, and are not completely effective. Various compounds including dialkylthioureas (such as diethylthiourea and dibutylthiourea) are known to reduce the corrosiveness of sulfuric acid on carbon steel. However, thioureas are undesirable for food and beverage applications.

[0006] The type of acid used can also present problems when developing acid cleaners. Many acid cleaners are based on phosphoric acid due to its various features, such as low corrosion behavior on many alloys and elastomers, good mineral solubility, and good scale suspension properties. Phosphoric acid has been subject to stricter wastewater regulations due to environmental and drinking water issues. It is therefore an object of the present invention to provide a cleaning composition that does not contain phosphorus.

[0007] Another object of the present invention is to provide aqueous nitric acid cleaning compositions which can be used on a variety of surfaces to provide enhanced fatty soil removal and soap scum removal which are particularly suitable for CIP and COP applications.

[0008] Another object of the present invention is to provide concentrated aqueous nitric acid cleaning compositions that provide phase stability at elevated temperatures without causing phase separation and / or loss of activity during storage.

[0009] Other objects, aspects, and advantages of the present invention will be apparent to those skilled in the art from the following disclosure, drawings, and appended claims. Summary of the invention

[0010] The compositions and methods of using the acidic cleaning compositions have the advantage of providing enhanced fatty soil removal and soap scum removal. Additionally, the acidic cleaning compositions are stable at elevated temperatures and have extended storage stability.

[0011] In one embodiment, the aqueous acidic cleaning composition comprises: at least about 30% active aqueous nitric acid solution; about 20-80% by weight water; and at least one of (A) about 0.01-1% by weight of at least two polyethoxylated fatty alcohols having different molecular weights and / or (B) about 0.01-0.5% by weight of a nonionic glucamide co-surfactant. The composition may further comprise at least about 40% of the actives of the cleaning composition. The composition may further comprise a polyethoxylated fatty alcohol comprising a mixture of at least one C12-C15 ethoxylated alcohol having an average of 7-12 moles of ethoxylation. The composition may further comprise a polyethoxylated fatty alcohol which is a blend of a mixture of two C12-C15 ethoxylated alcohols having an average of 7-12 moles of ethoxylation, including a mixture wherein the first polyethoxylated fatty alcohol is a mixture of C12-C14 ethoxylated alcohols having an average of 12 moles of ethoxylation, and wherein the second polyethoxylated fatty alcohol is a mixture of C12-C15 ethoxylated alcohols having an average of 7 moles of ethoxylation. The composition may further comprise (or alternatively comprise) a nonionic glucamide co-surfactant, including caprylyl / octyl methyl glucamide.

[0012] In another embodiment, the ratio of polyethoxylated fatty alcohol (wt%) to nitric acid (active %) in the cleaning composition may be between about 1:2000-1:800 when the nitric acid concentration is less than about 50 wt%, and between about 1:20-1:300 when the nitric acid concentration is greater than or equal to about 50% active. In other embodiments, the composition is in a concentrated form that can be diluted to a use concentration of the cleaning solution. In one embodiment, the composition is free of additional surfactants and / or acids. In a specific embodiment, the composition is free of alkyl polyglucosides and / or sulfuric acid. Preferably, the composition is free of phosphates, free of sulfuric acid, and free of sulfates. In other embodiments, the composition may also include at least one additional functional ingredient including an anti-foaming agent, an anti-redeposition agent, a bleaching agent, a solubility regulator, a dispersant, a rinse aid, a metal protector, a stabilizer, a corrosion inhibitor, a sequestrant and / or a chelating agent, a perfume and / or a dye, a rheology modifier and / or a solubility regulator or thickener, a hydrotrope or a coupling agent, a buffer and / or a solvent.

[0013] In one embodiment, the composition is phase stable and maintains surfactant stability as measured by less than a 10% change in IFT at a temperature of about 4-40°C for at least about three months.

[0014] Also included is a method for cleaning soil, and the method includes: applying any one of the cleaning compositions to a contaminated surface or object; and removing the soil from the surface. The soil may include organic soil, fatty soil, and / or soap scum. The surface or object may include stainless steel. According to an embodiment of the cleaning method, the contacting step may have a temperature of up to about 200°F. In an embodiment, the surface may include industrial equipment, a clean in place process, and / or a clean out of place process, and may be used for CIP or COP applications.

[0015] In one embodiment, the cleaning composition is applied to the surface or object for at least about 10 minutes and provides about 5000-40,000 ppm of total actives of the cleaning composition.

[0016] While multiple embodiments are disclosed, other embodiments will be apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments.Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The scale removal effectiveness of the evaluated acidic cleaning compositions relative to commercially available acidic cleaning compositions is shown.

[0018] Figure 2 The scale removal effectiveness of more evaluated acidic cleaning compositions relative to commercially available acidic cleaning compositions is shown.

[0019] Figure 3 The foaming height of the evaluated acidic cleaning compositions relative to commercially available acidic cleaning compositions is depicted.

[0020] Figure 4 Depicted are the foaming heights of the acidic cleaning compositions evaluated relative to commercially available acidic cleaning compositions when evaluating the test for reducing foam height over 5 minutes.

[0021] Figure 5 Displays a photo image analysis which converts the results into % dirt removal.

[0022] Various embodiments of the present invention will be described in detail with reference to the accompanying drawings, wherein the same reference numerals in several drawings represent the same parts. Mention of various embodiments does not limit the scope of the present invention. The accompanying drawings shown herein are not limitations of the various embodiments according to the present invention, but are intended to illustrate the present invention in an exemplary manner. DETAILED DESCRIPTION

[0023] The embodiments are not limited to a particular acid cleaning composition and method of CIP / COP use thereof, which may vary and are known to the skilled artisan. Applicants have unexpectedly discovered that a combination of polyethoxylated fatty alcohol surfactants at high nitric acid concentrations provides an effective acid cleaning solution that works well to remove tough fatty soils and soap scum and is suitable for use on a variety of surfaces, including stainless steel.

[0024] It should also be understood that all terms used herein are only used for the purpose of describing specific embodiments and are not intended to be limited in any manner or scope. For example, as used in this specification and the appended claims, the singular forms "a or an", "a or an" and "the" may include plural objects unless the content clearly indicates otherwise. In addition, all units, prefixes, and symbols may be represented in a form accepted by their SI. The numerical ranges mentioned in the specification include numbers within the defined ranges. Throughout the present invention, various aspects are given in the form of ranges. It should be understood that the description in the form of ranges is only for convenience and brevity and should not be construed as a rigid limitation on the scope of the invention. Therefore, the description of a range should be considered to have clearly disclosed all possible subranges and individual numerical values ​​within the range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5).

[0025] In order to more easily understand the present invention, some terms are first defined. Unless otherwise specified, all technical terms and scientific terms used herein have the same meanings as those of ordinary skill in the art to which embodiments of the present invention belong. In the practice of the embodiments, many methods and materials similar to or equivalent to those described herein or modified therefrom can be used without too much experimentation, but preferred materials and methods are described herein. When describing and claiming embodiments, the following terms will be used according to the definition given below.

[0026] As used herein, the term "about" refers to quantitative variations in values ​​that may occur, for example, due to typical measurements and liquid handling steps used in the real world to prepare concentrates or use solutions, inadvertent errors in these steps, differences in the manufacture, source, or purity of the ingredients used to prepare the composition or perform the method, etc. The term "about" also includes quantitative differences due to different equilibrium conditions of the composition resulting from a particular initial mixture. Whether or not modified by the term "about", the claims include quantitative equivalents.

[0027] The terms "active" or "active percent" or "active weight percent" or "active concentration" are used interchangeably herein and refer to the concentration of those ingredients that participate in cleaning, expressed as a percentage after deducting inert ingredients (such as water or salt).

[0028] As used herein, the term "cleaning" refers to methods used to promote or assist in soil removal, bleaching, microbial population reduction, and any combination thereof.

[0029] As used herein, the term "microorganism" refers to any non-cellular or unicellular (including colony) organism. Microorganisms include all prokaryotes. Microorganisms include bacteria (including cyanobacteria), spores, lichens, fungi, protozoa, prions, mimiviruses, viruses, bacteriophages, and some algae. As used herein, the term "microorganism" is synonymous with microorganisms. For the purposes of this patent application, the reduction of microorganisms is successfully achieved when the microbial population is reduced by at least about 50%, or is reduced significantly more than by washing. More microbial population reduction provides a higher level of protection.

[0030] As used herein, the term "free of" (e.g., "free of phosphorus," "free of sulfuric acid," and "free of sulfates") means that the composition is completely lacking the component or has such a small amount of the component that the component does not affect the performance of the composition. The component may be present as an impurity or as a contaminant and should be less than 0.5% by weight. In another embodiment, the amount of the component is less than 0.1% by weight, and in yet another embodiment, the amount of the component is less than 0.01% by weight.

[0031] As used herein, the term "phosphorus-free" refers to a composition, mixture, or ingredient that does not contain phosphorus or a phosphorus-containing compound or to which phosphorus or a phosphorus-containing compound has not been added. In the case where phosphorus or a phosphorus-containing compound is present through contamination of the phosphorus-free composition, mixture, or ingredient, the amount of phosphorus should be less than 0.5% by weight. The amount of phosphorus is more preferably less than 0.1% by weight, and the amount of phosphorus is most preferably less than 0.01% by weight.

[0032] As used herein, the terms "sulfuric acid-free" and "sulfate-free" refer to compositions, mixtures, or ingredients that do not contain sulfuric acid or sulfate, respectively. In the case of sulfuric acid or sulfate present through contamination of the composition, mixture, or ingredient, the amount of sulfuric acid or sulfate should be less than 0.5 weight %. The amount of sulfuric acid or sulfate is more preferably less than 0.1 weight %, and the amount of phosphorus is most preferably less than 0.01 weight %. Without being limited to a specific mechanism of action, acidic cleaning compositions are particularly well suited for cleaning high calcium soils (e.g., at least 2000 ppm, at least 2500 ppm, or even 3000 ppm calcium or higher), and the absence of sulfuric acid and sulfate ensures that calcium sulfate will not form and / or precipitate.

[0033] The term "surfactant" or "surface active agent" refers to an organic chemical that, when added to a liquid, changes the properties of the liquid at the surface.

[0034] As used herein, the terms "weight percent," "wt-%," "percent by weight," "% by weight," and variations thereof refer to the concentration of a substance by dividing the weight of the substance by the total weight of the composition and multiplying by 100. It should be understood that, as used herein, "percent," "%," and the like are intended to be synonymous with "weight percent," "weight %," and the like.

[0035] The methods and compositions may comprise, consist essentially of, or consist of the components and ingredients and other ingredients described herein. As used herein, "consisting essentially of" means that the methods and compositions may include additional steps, components, or ingredients, but only if the additional steps, components, or ingredients do not substantially change the basic and novel features of the claimed methods and compositions.

[0036] Acidic cleaning compositions

[0037] According to one embodiment, the acidic cleaning composition comprises a high concentration of at least 30% by weight nitric acid. The acidic cleaning composition comprises one or more polyethoxylated fatty alcohols, including a mixture of C12-C15 ethoxylated alcohols having an average of 7-12 moles of ethoxylation, and a nonionic cosurfactant, including glucamide. The acidic cleaning composition may include additional functional ingredients. Exemplary concentrated acidic cleaning compositions are shown in Tables 1-3, each in weight percent. Such exemplary acidic cleaning compositions are advantageously phosphate-free, sulfuric acid-free and / or sulfate-free.

[0038] Table 1

[0039]

[0040] Table 2

[0041]

[0042] Table 3

[0043]

[0044] The acidic cleaning composition may comprise a concentrate composition, or may be diluted to form a use composition. Generally speaking, a concentrate refers to a composition intended to be diluted with water to provide a use solution that provides the desired cleaning when contacted with an object. Depending on the formulation employed in the method according to the present invention, the acidic cleaning composition that will be contacted with the surface or object to be cleaned may be referred to as a concentrate composition or a use composition (or a use solution).

[0045] Nitric acid

[0046] The acidic cleaning composition contains a high concentration of nitric acid. Nitric acid is an inorganic acid formed by catalytic oxidation of ammonia with air to form nitrogen dioxide. When nitrogen dioxide is dissolved in water, 60% nitric acid is formed. 3NO2+H2O→2HNO3+NO. It has the abbreviated structural formula HNO3.

[0047] According to various aspects of the present invention and acidic cleaning compositions, nitric acid provides an acidic pH to the cleaning composition. Nitric acid further provides the benefit of a corrosion inhibitor. It has been unexpectedly discovered that at active percentages of at least about 30%, at least about 40%, or more, nitric acid in combination with a blend of surfactants disclosed herein provides a stable aqueous acid cleaning composition that is unexpectedly effective in removing scale from surfaces.

[0048] Typical acid cleaners contain about 1-30% by weight, or about 15-25% by weight of an acid or acid blend (e.g., sulfuric acid), and are diluted before being applied to the surface to be cleaned. The cleaning compositions disclosed herein can be provided with high concentrations of nitric acid (at least about 40-95% by weight, at least about 50-90% by weight, or at least about 60-90% by weight of nitric acid; or at least 30% of actives, at least 40% of actives, or more nitric acid), and can be diluted to provide about 0.1-4% or about 0.5-3.5% nitric acid in the use solution. In some embodiments, nitric acid is included in the acidic cleaning composition in an amount of at least about 40-95% by weight, about 40-90% by weight, about 40-80% by weight, about 50-90% by weight, or about 60-90% by weight. The weight percentage ranges disclosed herein are intended to include a range of nitric acid actives based on commercially available concentrated nitric acid. Nitric acid can be commercially available in various ranges. The most commonly used nitric acid (70%) is commercially available. Thus, the skilled artisan can determine the percentage of active nitric acid based on the weight percentage range and concentrated active nitric acid used in the formulation of the acidic cleaning composition. In a preferred embodiment, nitric acid is the only acid included in the cleaning composition. In a preferred embodiment, the cleaning composition does not contain sulfuric acid (sulphuric acid).

[0049] In some embodiments, the composition can be produced by first mixing water and nitric acid by a batch process or a continuous process and then adding a surfactant thereto.

[0050] Polyethoxylated fatty alcohol surfactants /

[0051] The acidic cleaning composition preferably includes at least one polyethoxylated fatty alcohol. The polyethoxylated fatty alcohol is a nonionic alcohol ethoxylate. The nonionic alcohol ethoxylate may also be an alkylphenol ethoxylate, preferably a fatty alcohol polyoxyethylene ether and / or a fatty alcohol polyoxyethylene nonylphenol ether surfactant. Exemplary commercially available polyethoxylated fatty alcohols include AEO-7 (a mixture of C12-C15 ethoxylated alcohols with an average of 7 moles of ethoxylation) and AEO-12 (a mixture of C12-C14 ethoxylated alcohols with an average of 12 moles of ethoxylation). The nonionic alcohol ethoxylate may also include ethoxylated oxo alcohols, including ethoxylated C11-oxo alcohols.

[0052] In one embodiment, at least one polyethoxylated fatty alcohol comprises AEO-7 (a mixture of C12-C15 ethoxylated alcohols having an average of 7 moles of ethoxylation) or AEO-12 (a mixture of C12-C14 ethoxylated alcohols having an average of 12 moles of ethoxylation). In a preferred embodiment, the polyethoxylated fatty alcohol comprises a combination of AEO-7 (a mixture of C12-C15 ethoxylated alcohols having an average of 7 moles of ethoxylation) and AEO-12 (a mixture of C12-C14 ethoxylated alcohols having an average of 12 moles of ethoxylation). It has been unexpectedly discovered that a combination of polyethoxylated fatty alcohols of different molecular weights formulated with high concentrations of nitric acid advantageously provides a stable concentrated acidic cleaning composition. Without being limited to a particular mechanism of action or theoretical mechanism of the invention, while the acidic cleaning composition containing the polyethoxylated fatty alcohol alone provides effective cleaning detergency for the surfactant, the combination of the polyethoxylated fatty alcohols ensures that the concentrated composition is not turbid and does not phase separate, while providing improved storage and shipping temperature stability, including low temperature stability of at least about 4°C.

[0053] As referred to herein, "temperature stability" means that the aqueous acidic cleaning composition does not become cloudy and does not phase separate at a temperature of from about 4-40° C. for at least about three months, and the stability of the surfactant is maintained in the composition. As referred to herein, the stability of the surfactant is measured by IFT (as described in the Examples) and has an IFT change of less than 10% at a temperature of from about 4-40° C. for at least about three months. The acidic cleaning composition advantageously provides a temperature stable composition, wherein the stability of the surfactant is retained when at least one polyethoxylated fatty alcohol and / or glucamide is employed.

[0054] The acid cleaning composition contains a surfactant to provide the desired cleaning action and to ensure good wetting of the surface treated with the acid cleaning composition. Although the surfactant concentrate can be added directly to the treatment solution, it is preferably added to the concentrate used when producing the use solution of the acid cleaning composition. In some embodiments, the polyethoxylated fatty alcohol is included in the acid cleaning composition in an amount of at least about 0-1% by weight, preferably about 0.01-1% by weight, about 0.015-1% by weight, about 0.05-1% by weight, about 0.1-1% by weight, or about 0.1-0.5% by weight.

[0055] In some embodiments, a C12-C14 ethoxylated alcohol having an average of 12 moles of ethoxylation is included in the acidic cleaning composition in an amount of at least about 0.01-1 wt%, about 0.05-1 wt%, about 0.05-0.5 wt%, or about 0.05-0.2 wt%, and a C12-C15 ethoxylated alcohol having an average of 7 moles of ethoxylation is included in the acidic cleaning composition in an amount of at least about 0.05-1 wt%, about 0.05-0.5 wt%, or about 0.1-0.5 wt%.

[0056] In other embodiments, the amount or concentration of the polyethoxylated fatty alcohol is dependent on the concentration of nitric acid. For cleaning compositions having a nitric acid concentration of less than about 50% active, the ratio of AEO-12 ethoxylated alcohol (wt%) having an average of 12 moles of ethoxylation to nitric acid (active%) is about 1:2000 to 1:200, while if the concentration of nitric acid is equal to or greater than about 50% active, the ratio of AEO-12 ethoxylated alcohol (wt%) having an average of 12 moles of ethoxylation to nitric acid (active%) is about 1:20 to 1:300.

[0057] Nonionic co-surfactant

[0058] The acidic cleaning composition preferably includes a nonionic co-surfactant. In one embodiment, the nonionic co-surfactant is a low foaming glucamide. Gluconamides include N-acyl N-alkyl derivatives of glucosamine (also known as glucamide, GA, fatty acid glucamide, or FAGA). An exemplary glucamide is caprylyl / octyl methyl glucamide, which can be obtained from Glucopure WET TM Commercially available from Clariant.

[0059] Preferably, a glucamide surfactant is included in the acidic cleaning composition rather than a nonionic alkyl polysaccharide surfactant.

[0060] In some embodiments, a nonionic co-surfactant, preferably glucamide, is included in the acidic cleaning composition in an amount of at least about 0-1 wt%, about 0.01-1 wt%, about 0.01-0.5 wt%, about 0.015-0.5 wt%, about 0.1-0.5 wt%.

[0061] Additional functional ingredients

[0062] The components of the acidic cleaning composition can be further combined with various functional components suitable for the uses disclosed herein, including hard surface cleaning, CIP and COP applications. In some embodiments, the acidic cleaning composition including nitric acid, water, polyethoxylated fatty alcohols and / or nonionic glucamide co-surfactants constitutes a large amount, or even substantially all, of the total weight of the acidic cleaning composition. For example, in some embodiments, little or no additional functional ingredients are added thereto.

[0063] In other embodiments, additional functional ingredients may be included in the acidic cleaning composition. The functional ingredients provide the composition with desired properties and functions. For the purposes of this application, the term "functional ingredient" includes materials that provide beneficial properties in specific uses when dispersed or dissolved in a use solution and / or a concentrate solution (e.g., aqueous solution). Some specific embodiments of functional materials are discussed in more detail below, although the specific materials discussed are only given by way of example, other functional ingredients of a wide range may also be used. For example, many functional materials discussed below relate to materials used in cleaning. However, other embodiments may include the functional ingredients used in other applications.

[0064] In some embodiments, the acidic cleaning composition may include defoamers, anti-redeposition agents, bleaches, solubility modifiers, dispersants, rinse aids, metal protectants, stabilizers, corrosion inhibitors, sequestrants and / or chelating agents, fragrances and / or dyes, rheology modifiers and / or solubility modifiers or thickeners, hydrotropes or coupling agents, buffers, solvents, and the like.

[0065] According to an embodiment of the present invention, the various other functional ingredients can be provided in the composition in an amount of about 0-90 % by weight, about 0-75 % by weight, about 0-50 % by weight, about 0.01-50 % by weight, about 0.1-50 % by weight, about 1-50 % by weight, about 1-30 % by weight, about 1-25 % by weight, or about 1-20 % by weight. In addition, and not limited by the present invention, all ranges mentioned include the numerical value defining the range, and include each integer within the range of the definition.

[0066] In a preferred embodiment, urea is preferably included as a hydrotrope or solubility modifier of the acidic cleaning composition. In an exemplary embodiment, urea is included in the acidic cleaning composition in an amount of about 0.01-10 wt%, about 0.05-1 wt%.

[0067] These and other additional functional ingredients may also be included, including (but not limited to) wetting agents to reduce the surface tension of the solution, solvents to help remove hydrophobic soils, defoamers to prevent foam or foam accumulation on the surface of the solution, (acid-stable) thickeners to allow the cleaning agent to adhere (attach to vertical surfaces), passivators to protect the surface from environmental attacks, and biocides to control odor problems and kill harmful bacteria. Dyes and other components may also be added.

[0068] Aesthetic enhancers such as colorants and fragrances may also be optionally added to the acidic cleaning composition. Examples of fragrances or aromas that may be used in the acidic cleaning composition include, but are not limited to, liquid fragrances.

[0069] It should be understood that the water provided as part of the solution or concentrate of the acidic cleaning composition may be substantially free of hardness. It is contemplated that the water may be deionized to remove most of the solids dissolved in the water. The concentrate is then diluted with water available locally or at the dilution site, which may have varying degrees of hardness depending on the locality. Although it is preferred to use softened or deionized water to formulate the concentrate, the concentrate may be formulated using non-deionized water. That is, the concentrate may be formulated using water that includes dissolved solids, and may be formulated using water characterized as hard water.

[0070] How to use

[0071] The acidic cleaning composition is suitable for cleaning hard surfaces and objects. The acidic cleaning composition can effectively clean and remove soils from such surfaces and objects, including (for example) fat and protein soils, organic soils, and films / foams left as residues on surfaces and objects, such as from CIP processes. In a specific embodiment, the acidic cleaning composition can effectively remove calcium stearate and other soap scum soils from the surface.

[0072] In some respects, acidic cleaning compositions are particularly well suited for cleaning in place (CIP) and cleaning outside positioning (COP) applications. CIP applications include acidic cleaning compositions that do not require those of disassembly equipment through pipelines. COP systems can include easily accessible systems, including sinks, soaking containers, mop buckets, water storage tanks, sinks, auto parts washers, discontinuous intermittent washers and systems, etc. In some respects, acidic cleaning compositions are further suitable for removing mineral dirt. For example, acidic cleaning compositions can be used for stainless steel pipes that need to use acid cleaners to remove alkali on the surface.

[0073] Exemplary industries to which the methods of the present invention may be applied include, but are not limited to: the food and beverage industry, such as the dairy, cheese, sugar, and brewing industries, including, for example, evaporator and pasteurizer cleaning, including ultra-high temperature (UHT) and high temperature short time (HTST) pasteurizers; the petroleum processing industry; industrial agriculture and ethanol processing; and the pharmaceutical manufacturing industry.

[0074] In some aspects, the method of using the acidic cleaning composition comprises applying the composition to or contacting the composition to equipment, such as industrial equipment that is typically cleaned using a cleaning-in-place cleaning step. Examples of such equipment include evaporators, heat exchangers (including shell-and-tube heat exchangers, direct steam injection, and frame-and-plate heat exchangers), heating coils (including steam, flame, or heated heat exchange fluids) recrystallizers, crystallization trays, spray dryers, drum dryers, membranes, and tanks.

[0075] Conventional CIP processes are generally well known. The process involves applying or circulating a water-diluted solution of a cleaning concentrate (typically about 0.5 to 3% by volume) to the surface to be cleaned. The solution flows over the surface (3 to 6 feet per second) to remove scale. As needed, new solution is reapplied to the surface, or the same solution is recirculated and reapplied to the surface to obtain a clean, scale-free surface.

[0076] A typical CIP process for removing scale (including organic components, inorganic components, or a mixture of these two components) usually includes at least three steps: an initial water rinse or a previously used chemical rinse, an alkaline solution wash and / or an acid solution wash, and a final fresh water rinse. Additional steps may include a separate acid wash step or alkaline wash step and a separate sterilization step. The alkaline solution softens the scale and removes organic alkaline-soluble scale. The acid solution removes any remaining mineral scale. The strength of the alkaline and acid solutions, the duration of the cleaning step, and the temperature of the cleaning solution generally depend on the amount and toughness of the scale. The water rinse removes any residual chemical solution and scale before the equipment is put back online for production purposes.

[0077] The acidic cleaning composition can be applied to the surface using various methods. These methods can be performed on an object, surface, etc. by contacting the object or surface with the composition. Contacting can include any of a variety of liquid application methods, such as spraying the compound, immersing the object in the compound, treating the object with a foam or gel of the compound, or a combination thereof. Without being limited to contacting according to the present invention, the concentrate liquid composition or the use liquid composition can be applied to the object or contacted with the object by any conventional method or device used to apply the liquid composition to the object. For example, the surface can be scrubbed, sprayed with the liquid composition or the use liquid composition prepared from the concentrated liquid composition, foamed in the liquid composition or the use liquid composition prepared from the concentrated liquid composition, and / or immersed in the liquid composition or the use liquid composition prepared from the concentrated liquid composition. The liquid composition can be sprayed, foamed, or scrubbed onto the surface; the compound can be made to flow over the surface, or the surface can be immersed in the compound. Contacting can be performed manually or by machine.

[0078] The acidic cleaning composition is contacted with a surface or object for a sufficiently long time to clean the surface or object. In one aspect, the surface or object is contacted with the acidic cleaning composition for at least about 1 minute, at least about 10 minutes, or about 10-20 minutes. The acidic cleaning composition can be applied to the surface or object that needs to be cleaned using a solution or a concentrated solution. In one aspect, the use concentration of the acidic cleaning composition includes about 1000-50,000ppm, or about 5000-50,000ppm, or about 5000-40,000ppm, including all ranges therebetween.

[0079] The acidic cleaning composition can be applied as a use solution or a concentrated solution with a pH of about <0-2, or between about 0-2, or preferably between about 0.5-2. In a preferred aspect, the pH of the use concentration (i.e., the diluted concentrate composition) is between about 0.5-2. Without being limited to the dilution ratio of the concentrate acidic cleaning composition, in some embodiments, the concentrate can be diluted to about 0.1-4% of the formulation, or about 0.5-4% of the formulation.

[0080] Example

[0081] In the following non-limiting examples, embodiments of the present invention are further described. Although it should be understood that these embodiments show certain embodiments of the present invention, they are only for illustration. From the above discussion and these embodiments, those skilled in the art can determine the basic characteristics of the present invention, and can make various changes and modifications to the embodiments of the present invention without departing from its spirit and scope, so that it is suitable for various purposes and conditions. Therefore, in addition to those shown and described herein, the various changes of the embodiments of the present invention will be apparent to those skilled in the art from the above. This change is intended to also fall within the scope of the appended claims.

[0082] The following ingredients were used in each example:

[0083] Glucopure WET——NC 8-10 -Alkanoyl-n-methylglucosamine, CAS 91782-62-5

[0084] AEO-7 - Straight chain alcohol 60-70% ethoxylate, 7EO

[0085] AEO-12——Alcohol (C12-C14) 12EO

[0086] Genapol UD 110——C 11 -oxo alcohol polyglycol ether with 11 moles of EO

[0087] Luntensol XL89 - Oxirane, 2-methyl-, polymer with ethylene oxide, mono(2-propylheptyl) ether

[0088] Tego XP 1075 - low foaming anionic / amphoteric surfactant blend, available from Evonik Industries AG

[0089] Example 1

[0090] The formulations shown in Tables 4 to 5 were prepared according to the following steps: First add water to the mixer and stir. Add urea and mix to completely dissolve. Add nitric acid and mix for 5 minutes, then add the remaining components and mix for another 5 minutes.

[0091] Table 4

[0092]

[0093]

[0094] Table 5

[0095]

[0096] The stability of the formulations was evaluated at 4°C, room temperature and 40°C and the results are shown in Tables 6-7.

[0097] Table 6

[0098] Sample code 0224A 0306B 0315A 0316A 0410A 0223A 0906A 4℃ Can Can Can Can Can Can Deposition Room temperature Can Can Can Can Can Can Can 40℃ Can Can Can Can Can turbid Can

[0099] Table 7

[0100] Sample code 0713A 0713B 0713C 0713D 4℃ Can Can Can Can Room temperature turbid turbid Can Can 40℃ Separation Separation turbid Can

[0101] The stability results show that when nitric acid is increased to 50% active in the formulation in the formulation evaluated in Table 5 (compared to 40% active for the formulation in Table 4), additional AEO-12 is required to stabilize the formulation. The AEO-7 (0.1%), AEO-12 (0.2%) formulation is stable, and if the AEO-12 is less than 0.15%, turbidity or separation occurs at 40°C. The results confirm that the combination of ethoxylated fatty alcohol surfactants, AEO-7 and AEO-12 (also in combination with the glucamide nonionic surfactant), is stable at different temperatures.

[0102] Example 2

[0103] The performance of the formulations was tested to evaluate the removal efficacy of fatty soils. A thin cream dairy soil (with Sudan IV) was prepared and analyzed to evaluate the ability to remove soils commonly found in cold dairy applications. Most often, when inadequate cleaning is observed in cold dairy applications, it is not a thick soil that is left behind; instead, a thin film of fat and / or protein is observed on steel and gasket materials. This can often be difficult to see. This test reproduces the thin residue and compares the performance of the two formulations for soil removal.

[0104] The Example 1 formulation of the room temperature stability sample was analyzed. The stainless steel coupons were contaminated for cleaning testing. The cleaning test conditions were 70°C, 350RPM, 20 minutes. The test measurements of L, a, and b were read on a HunterLab Color Quest Spectrophotometer to evaluate the color test and the soil removal rate (%) was calculated by the color readings. In this color space, L* represents brightness, a* and b* measure chromaticity, +a* is the red direction, -a* is the green direction, +B* is the yellow direction, and -b* is the blue direction. The results are recorded as the change in ab* value for a specific treatment. For more information, see the HunterLab procedure. Cleaning tests were performed only on the Example 1 formulations that passed the stability test. They were further compared with the commercially available acidic cleaning composition Horolith NP (Ecolab, Inc.).

[0105] Figure 1 The cleaning results, shown as Soil Removal (Δ%), are shown showing that formulations 0223A (nitric acid, ethoxylated fatty alcohols, and glucamide nonionic surfactants) and 0224A (nitric acid and ethoxylated fatty alcohols) perform better than 0410A (nitric acid and Lutensol XL89 formulation) and a commercial control nitric acid / urea formulation (Horolith NP, Ecolab). These results show overall improved performance of formulations including ethoxylated fatty alcohols (including AEO-7 and AEO-12 surfactants).

[0106] Example 3

[0107] Additional performance testing was performed using the formulation of Example 1, 40°C stability sample as shown in Example 2. Table 8 shows Figure 2 data.

[0108] The number of days next to each formulation in Table 8 refers to how many days it was stable at 40°C when the cleaning test was performed. Δa% refers to Δ soil removal rate. Soil removal rate = (a0-a)*100% / a0; a0 = soiled test piece data; a = reading of the clean test piece.

[0109] Table 8

[0110]

[0111] Figure 2 The cleaning results are shown as the average of 4 tests showing soil removal (Δa%), which show that formulations 0223A (nitric acid, ethoxylated fatty alcohol, and glucamide nonionic surfactant formulation) and 0224A (nitric acid and ethoxylated fatty alcohol formulation) perform better than formulations with only glucamide nonionic surfactant, including 0906A (nitric acid and glucamide nonionic formulation), 0316A (nitric acid and C with 11 moles EO) and 0316A (nitric acid and C with 11 moles EO). 11 -oxo alcohol polyglycol ether formulation) as well as a commercial control sulfuric acid / nitric acid formulation). The results confirm that the surfactant is stable in the formulation as shown by the maintained soil removal ability.

[0112] Example 4

[0113] The removal efficiency of calcium oleate was analyzed according to the following method (as provided by the supplier Clariant): A formulation of 250 g / CaCl2 solution and 5% sodium oleate solution was prepared. The CaCl2 solution was sprayed onto a clean stainless steel (SS) coupon, and then the same amount of sodium oleate solution was sprayed onto the SS coupon to form a uniform white film fouling. They were allowed to stand at room temperature for 4 hours and then placed in a cleaning in place (CIP) solution for 15 minutes. After cleaning, the coupons were removed, photo images were taken, and the results were analyzed by Image J based on the level of fouling residue.

[0114] Each photo image is Figure 5 As shown in the figure, the black area in the conversion image is a clean area, which is more likely to show the cleaning effect of dirt removal. The analysis results of the evaluated test pieces are also shown in Table 9.

[0115] Table 9

[0116] serial number Test piece name area average value Standard Deviation Minimum maximum % Area (clean) 1 Contaminated test piece 720000 13.236 56.569 0 255 5.191 2 0224A Cleaning 720000 174.403 118.559 0 255 68.393 3 Horolith NP Cleaning 720000 118.182 127.159 0 255 46.346

[0117] Formulation 0224A was evaluated against a commercial control, Horolith NP (a nitric acid / urea formulation without ethoxylated fatty alcohol surfactant). Formulation 0224A removed essentially all of the calcium oleate soil, while the control removed some of the covered calcium oleate. Figure 5 These results were observed, with image analysis showing that 0224A cleaned a larger area (and therefore removed more soil) than Horolith NP.

[0118] Example 5

[0119] Interfacial tension testing was performed to evaluate the stability of the surfactants in the formulations disclosed herein. IFT (interfacial tension) was analyzed at room temperature based on surface tension and contact angle as shown in Table 10.

[0120] Table 10

[0121]

[0122] The IFT of the new sample of Glucopure WET is close to the IFT of the 2-year-old sample, indicating that Glucopure WET is stable under 40% nitric acid. The IFT of the new sample of Tego XP 1075 is different from the IFT of the 2-year-old sample, indicating that Tego XP 1075 cannot be used in a formulation under 40% nitric acid.

[0123] The formulations were also analyzed for surfactant stability in nitric acid formulations >40% as shown in Table 11. Control formulations, Horolith NP (nitric acid / urea) and Horolith LT (nitric acid / sulfuric acid with AEO-7), were evaluated.

[0124] Table 11

[0125]

[0126] The IFT [mN / m] in Table 11 was tested at 124 days using the 40°C stability samples. The IFT was tested at 124 days for the 0224A formulation at 40°C and the IFT results remained close to the IFT results of the fresh samples [0224A fresh sample, concentrated 23.93+-0.12; 3.00% 48.50+-1.43], which means that the surfactant blend survived in 40% active nitric acid.

[0127] Surfactants reduce the IFT of both the concentrated product and the diluted solution, which means that adding surfactant to the formulation helps the wetting of the formulation compared to the product without ethoxylated fatty alcohol surfactant. This result is consistent with the cleaning performance results.

[0128] Example 6

[0129] A foaming test was also performed. The concentration was 1.5% (wt / v) and the mixture was circulated for 5 minutes. Figure 3 and Figure 4 As shown, Reference A is a commercial control product (Horolith LT; sulfuric acid / nitric acid formulation; Ecolab) and Reference B is a commercial control product (Stabicip HH; 30 to 50% alcohol, C12-16 ethoxylated; Ecolab). Foaming tests used circulation volumes ranging from 120 ml to 600 L. Figure 3 0224A foaming was shown to be acceptable along with all other formulations evaluated.

[0130] A foam reduction test was then performed. The foam was monitored for 5 minutes after the pump was stopped. During CIP operation, if the foam is not reduced quickly, it will accumulate in the CIP tank, which will have a negative impact on the CIP. Figure 4 The 0224A foam is shown to decrease at the expected rate.

[0131] Example 7

[0132] A calcium salt precipitation test was performed. Reagent grade calcium phosphate / calcium stearate was added to the test solution at a concentration of 2%. An excess of calcium phosphate / calcium stearate was then added so that a precipitate appeared at the bottom of the beaker. Magnetic stirring was started at 500 rpm and the solution was heated to the use temperature (60°C). The solution was covered to avoid evaporation of water and allowed to stand for 30 minutes. The magnetic stirring was turned off and the solution was allowed to cool for 1 hour. A sample of the supernatant was taken with a syringe and filtered through a 0.2 micron filter. The filtrate was analyzed for calcium by CIP in order to quantify the calcium in the solution.

[0133] The results are shown in Table 12.

[0134] Table 12

[0135]

[0136] For Ca3(PO4)2 removal, it is more related to the nitric acid content in the solution, so all formulations are close. However, for calcium stearate, the formulations with surfactants show improved removal performance over conventional CIP acid cleaners, with the exception of 0410A.

[0137] It should be understood that although the invention has been described in conjunction with its detailed description, the above description is intended to be illustrative and is not intended to limit the scope of the invention, which is defined by the scope of the appended claims. Other embodiments, advantages, and modifications are within the scope of the following claims. In addition, the contents of all patent publications discussed above are incorporated herein by reference in their entirety.

Claims

1. An aqueous acidic cleaning composition comprising: An aqueous solution of at least about 30% active nitric acid; about 20-80% by weight water; and At least one of (A) about 0.01-1 wt. % of at least two polyethoxylated fatty alcohols having different molecular masses and / or (B) about 0.01-0.5 wt. % of a nonionic glucamide co-surfactant.

2. The composition of claim 1, wherein the aqueous nitric acid solution comprises at least about 40% of the active matter of the cleaning composition.

3. The composition of any one of claims 1-2, wherein the polyethoxylated fatty alcohol comprises a mixture of at least one C12-C15 ethoxylated alcohol having an average of 7-12 moles of ethoxylation.

4. The composition of any one of claims 1-2, wherein the polyethoxylated fatty alcohol is a blend of two C12-C15 ethoxylated alcohol mixtures having an average of 7-12 moles of ethoxylation.

5. A composition according to claim 4, wherein the first polyethoxylated fatty alcohol is a mixture of C12-C14 ethoxylated alcohols having an average of 12 moles of ethoxylation, and wherein the second polyethoxylated fatty alcohol is a mixture of C12-C15 ethoxylated alcohols having an average of 7 moles of ethoxylation.

6. The composition of claim 5, further comprising the nonionic glucamide co-surfactant.

7. The composition of any one of claims 1-2, wherein the nonionic glucamide surfactant is capryl / octyl methyl glucamide.

8. The composition of claim 5, wherein the ratio of the mixture of C12-C14 ethoxylated alcohols having an average of 12 moles of ethoxylation (wt %) to nitric acid (active %) is between about 1:2000-1:200 when the concentration of nitric acid is less than about 50% active, and between about 1:20-1:300 when the concentration of nitric acid is greater than or equal to about 50% active.

9. The composition of claim 1, wherein the composition is in a concentrated form that can be diluted to a use concentration in a cleaning solution.

10. The composition of claim 1, wherein the composition is free of additional surfactants and / or acids.

11. The composition of claim 10, wherein the composition is free of alkyl polyglucoside and / or sulfuric acid.

12. The composition of claim 1, wherein the composition is phosphate-free, sulfuric acid-free, and sulfate-free.

13. A composition according to any one of claims 8 to 12, further comprising at least one additional functional ingredient comprising an anti-foaming agent, an anti-redeposition agent, a bleaching agent, a solubility regulator, a dispersant, a rinse aid, a metal protector, a stabilizer, a corrosion inhibitor, a sequestrant and / or a chelating agent, a fragrance and / or a dye, a rheology modifier and / or a solubility regulator or thickener, a hydrotrope or a coupling agent, a buffer and / or a solvent.

14. The composition of claim 1, wherein the composition is phase stable and maintains surfactant stability as measured by less than a 10% change in IFT at a temperature of about 4-40°C for at least about three months.

15. A method for cleaning dirt, comprising: Applying the cleaning composition of any one of claims 1 to 14 to a contaminated surface or object; and Dirt is removed from the surface.

16. The method of claim 15, wherein the soil comprises organic soil, fatty soil and / or soap scum.

17. The method of claim 15, wherein the surface or object comprises stainless steel.

18. The method of claim 15, wherein the contact temperature of the surface is up to about 200°F.

19. The method of any one of claims 15-18, wherein the surface comprises industrial equipment, a clean-in-place process, and / or a clean-out-of-place process.

20. The method of claim 15, wherein the cleaning composition is used in CIP or COP applications.

21. The method of claim 15, wherein the cleaning composition is applied to the surface or object for at least about 10 minutes and provides about 5000-40,000 ppm of total actives of the cleaning composition.

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