LOW-FOAMING COMPOSITIONS

Abstract: Detergent and detergent-sanitiser compositions suitable for high pressure, clean-in-place and closed circuit cleaning procedures for use in the dairy and in soft drink and other food processing equipment. The detergent sanitiser compositions of the invention are useful in the treatment of bulk volumes of water such as public water supplies, swimming pools, holding tanks and the like. The present invention provides a low-foaming composition comprising: a first non-ionic surface active agent having a cloud point of less than 40<o>C in a 1% aqueous solution; and a hydrotrope and/or a co-solvent for said surface active agent.

Description: DESCRIPTION LOW-FOAMING COMPOSITIONS TECHNICAL FIELD The present invention relates to detergent and detergent-sanitiser compositions suitable for high pressure, clean-in-place and closed circuit cleaning procedures for use in the dairy and in soft drink and other food processing equipment. The detergent sanitiser compositions of the invention are useful in the treatment of bulk volumes of water such as public water supplies, swimming pools, holding tanks and the like. Until the present invention it has been difficult to provide suitable detergent and detergent-sanitiser compositions with the desired low foam characteristics for such purposes. BACKGROUND ART Although many propositions have been made for low foaming detergent compositions which usually were a combination of a nonionic surface active agent with a foam depressant, there is still a need for such low foaming detergent compositions, especially when the detergent solutions are used at elevated temperatures. Some cleaning and cleaning-sanitising operations can be carried out satisfactorily with cold water at ambient temperatures, it is often preferred to work at higher operating temperatures. Thus, while some detergent compositions based on nonionic surfactants are often preheated to operating temperatures above 35° C, they will generate only little foam in the upper range of their temperature, but on cooling down, which takes place rapidly during the cleaning operation, the foam generation will gradually increase even in the presence of defoaming agents. The availability of detergent compositions of low foam characteristics at ambient temperatures is of greatest importance for special purpose detergent-sanitiser compositions incorporating iodine as its complex with a nonionic surfactant, known as an iodophor. It is generally recognised that iodine has distinct SM/323C advantages over chlorine for water treatment, which today is either used by itself or in the form of chlorine generating substances, as the most widely used water disinfectant. Not only is iodine considerably more effective against most pathogenic organisms, and therefore can be used at lower concentrations than chlorine, but iodine does not impart disagreeable odour or taste to the water. This makes it eminently suitable for potable water and for use in swimming pools. Added advantages of using iodine in the treatment of swimming pool water are that it eliminates the inconvenience of regular pH control, and that unlike chlorine and bromine it does not react with ammonia, amines or like compounds such as urea to form compounds responsible for irritation of the eyes and mucous membranes, associated with chlorinated swimming pool water. Furthermore, the level of iodine concentration in the water is less liable to reduction by pollution. The importance of iodine for the treatment of municipal water and swimming pools has been recognised by the American Public Health Association, which has set a minimum of 0.2 ppm of iodine for disinfection. The efficiency of iodine in water disinfection, especially in emergency conditions, is illustrated by the fact that highly contaminated water with a bacterial count of 10 organisms per ml is reduced within 10 minutes at 25°C to drinking water quality of 10 organisms per 100 ml by the addition of 3.0 to 4.0 ppm iodine. As idophors were known to have inherant foaming properties and were thus unsuitable for water treatment, many proposals have been made to provide suitable water treatment methods using iodine, other than as an iodophor as the disinfecting agent. If chlorine has so far maintained its predominant position in the treatment of water for domestic, public and industrial waters, it is only due to the technical difficulties and high costs which have prevented up to date the general use of iodine based water disinfectants. DESCRIPTION OF THE INVENTION The present invention relates to detergent and detergent-sanitizing compositions and to water treatment SM/323C compositions which maintain low-foaming characteristics over a wide range of operating temperatures at which cleaning and cleaning-sanitising operations and water treating processes are performed. The low-foaming detergent and detergent-sanitising compositions of the invention are suitable for use at ambient temperatures and for treatment bulk volumes of water. Low foaming detergent compositions of the invention which may incorporate an iodophor, are suitable for pressure clean-in-place and closed circuit cleaning at ambient temperatures, encountered under normal climatic conditions. The present invention provides a low-foaming composition comprising: a first non-ionic surface active agent having a cloud point of less than 40°C in a 1% aqueous solution; and a hydrotrope and/or a co-solvent for said surface active agent. It is advantageous but not essentially required to add an additional nonionic surface active agent having a lower hydrophilic-lipophilic balance. Usually, the second surface active agent will be employed in a lesser amount than the first surface active agent. Either surface active agent may contain up to 30% by weight of iodine in the form of an iodophor. Usually, the first surface active agent will contain the iodine. It was surprisingly found that low foaming nonionic surface active agents having a cloud point in a 1.0% aqueous solution of below 40° C when solubilised by a hydrotrope or a co-solvent or a mixture of both retain their low-foaming characteristics over a wide range of temperatures when preheated solutions are then cooled and can also be used at ambient cold water temperatures. It has further been found that the solubilising effect of the hydrotrope is not restricted to nonionic surface active agents, but also to complexes formed between nonionic surface active agents and iodine without any loss of antibacterial activity. Such complexes are known as iodophors. In some cases the hydrotropes will cause the formation of stable dispersions at operating temperatures. However, SM/323C these dispersions retain their cleansing properties, and where they incorporate iodine, also their disinfecting properties. There are many ways known and duly described as to how the complex formation of the iodine with the surface active agent is achieved. However, the simplest and most practical way is by dissolving the iodine directly in an excess of the surface active agent or mixing iodine with the surface active agent separately to an available iodine content up to about 30% by weight based on the combined weight. For use for water treatment an available iodine content of about 5% to about 15% is preferred. If the iodophor is not directly made with the nonionic surface active agent used in the composition, it is added. In the case of a detergent-sanitizer which contains an iodophor, it is preferred that an acid, such as phosphoric acid, hydrochloric acid, sulfuric acid, sulfamic acid, preferably phosphoric acid or sulfamic acid or a mixture thereof, is added to give the use dilution a pH below about 5 preferably between about 1.5 and about 5. and more preferably between about 3 and about 5. The amount of iodophor is calculated so that the final detergent sanitizing composition has an available iodine content between about 0.2 and 3.0%. For water treatment compositions can contain up to 30% w/v available iodine. The compositions of the invention also find use in treatment of bulk volumes of water. Accordingly, the invention also provides a method for water disinfection which comprises adding an effective amount of a composition of the invention which contains iodine to the water to be treated so as to achieve an iodine content of from about O.lppm to about lOppm. Conventional iodophors are not suitable as their use would result in unacceptable foaming in use in municipal water treatment, swimming pools, air conditioning cooling water and the like. For the treatment of highly contaminated water for drinking purposes, an iodine level of about 4.0ppm to about β.Oppm might be necessary, whereas about 0.2ppm to about SM/323C 0.4ppm is usually sufficient to keep the water in swimming pools at a satisfactory quality. The preferred surface active agents are those derived from alkyl-or dialkyl-phenols having 5 to 7 ethoxy groups per molecule or the ethylene oxide copolymers with propylene oxide. The surface active agent can be used alone or in combination with other suitable nonionic surface active agents having similar cloud point characteristics. Other suitable nonionic surface active agents are those selected from copolymers of ethylene oxide with propylene oxide or the ethylene oxide condensates with alkyl or dialkylphenols, fatty acid alcohols or acids. Suitable hydrotropes are, for example, the water soluble salts of toluene sulfonates.xylene sulfonates.cumene sulfonates or naphthalene sulfonates. preferably cumene sulfonates. Suitable as co-solvents are lower alcohols such as methanol. ethanol. propanol or isopropanol, or propylene glycol or a polyethylene glycol. Propylene glycol is the co-solvent of preference. The amount of hydrotrope or co-solvent to be added is established by stirring the nonionic surface active agents with the iodophor. if present, in approximately three quarters of the final volume of water, at the lowest temperature at which the detergent composition is expected to operate, and adding sufficient hydrotrope or co-solvent until a clear solution or stable suspension is obtained. MODES FOR CARRYING OUT THE INVENTION The following examples illustrate preferred embodiments of the present invention. They should not be construed as binding to the claims hereto. Unles otherwise indicated, the ingredients are combined by standard cold mixing processes. EXAMPLE 1 Low foaming detergent for clean-in-place cleaning parts by weight nonyl phenol ethoxylate(6 mol ethoxy) 70.0 sodium xylene sulfonate 40% solution 40.0 sodium metasilicate 50.0 sodium tripolyphosphate 30.0 water, to make 1000.OmL SM/323C EXAMPLE 2 Low foaming detergent for closed circuit cleaning of soft drink and similar filling equipment. parts by weight copolymer of ethylene oxide with propylene oxide* 40.0 sodium salt of cumene sulfonate 40% 150.0 tetrapotassium polyphosphate 100.0 disodium ethylene diaminetetraacetate 20.0 water to make 1000.OmL * (Teric PE 61. available from I.C.I. LTD. UK or Plurionic L 61 from Wyandotte Chemical Corp. USA.) EXAMPLE 3 Detergent - sanitizer for the dairy industry parts by weight nonyl phenol ethoxylate(7 mol ethoxy) 21.0 nonyl phenol ethoxylate(5 mol ethoxy) 1.5 iodine 1.9 sodium cumene sulfonate 35.0 phosphoric acid 85% 160.0 water, to make 1000.OmL The iodine was dissolved by stirring it in the excess of the nonyl phenol ethoxylate(7 mol ethoxy). to complex the iodine, at a temperature between 45° to 60°C until all iodine has gone into solution whereupon the rest of the nonyl phenol ethoxylate was added. The resulting mixture was cooled to ambient temperature and added with light agitation to the mixture of the sodium cumene sulfonate, phosphoric acid and water until a homogeneous solution was obtained. The detergent sanitizer concentrate thus obtained has an available iodine content of approximately 1.75% and is to be diluted according to ; plication to an available iodine content from 175 ppm to 25 ppm. SM/323C EXAMPLE 4 Low foam powder detergent sanitizer for the food industry parts by weight monyl phenol ethoxylate (7 mol ethoxy) 14.5 iodine 1.2 potassium xylene sulfonate (solid) 16.0 sulfamic acid 9.0 sodium bisulfate (anhydrous) 5.0 urea 54.3 The idoine was dissolved in a normal manner into non-ionic surface active agent. The dark paste obtained was mixed with the rest of the dry ingredients to produce, after grinding, a free flowing powder easily dispersable in water containing approximately 1% w/w available iodine. On dilution to a use concentration in water of 25 to 75 ppm a light yellowish/ brown, slightly hazy solution was obtained. EXAMPLE 5 Water Treatment Composition 11.0kg of finely powdered iodine was added to 50.0kg of nonylphenolethoxylate(6 mol ethoxy) and 2.0kg propylene glycol at a temperature of about 40°C. The mixture was gently stirred until the iodine dissolved. The resulting solution was cooled to ambient temperature and added to 36.0kg of a 40% solution of sodium comeno sulfonate and 1.0kg of 75% phosphoric acid with sufficient mixing until an even homogeneous fluid was obtained. EXAMPLE 6 Water Treatment 3 To a swimming pool containing 50m of water 200mL of a composition, as described in the following example, was added slowly and with simultaneous stirring to approx. 10.OL of water in a bucket. The resulting turbid solution was then added in small portions to various parts of the swimming pool. A level of 0.2ppm was maintained daily, additions to the swimming pool of half the quantity of the composition (lOOmL) in the manner described. SM/323C

Claims: CLAIMS 1. A low-foaming composition comprising: a first non-ionic surface active agent having a cloud point of less than 40°C in a 1% aqueous solution; and a hydrotrope and/or a co-solvent for said surface active agent. 2. A composition as defined in claim 1. further comprising a second non-ionic surface agent having a cloud point of less than 40°C in a 1% aqueous solution and having a lower hydrophilic-lipophilic balance than said first surface active agent. 3. A composition as defined in claim 1 or claim 2. wherein said first and/or second surface active agent contain up to about 30% by weight of available iodine in the form of an iodophor. 4. A composition as defined in any one of claims 1 to 3, wherein the first or second surface active agent is an ethylene oxide condensate with an alkyl or dialkyl phenol, a fatty acid alcohol or acid, or a copolymer of ethylene oxide and propylene oxide. 5. A composition as defined in claim 4. wherein the ethylene oxide condensate with an alkyl or dialkyl phenol has 5 to 7 ethoxy groups per molecule. 6. A composition as defined in any one of claims 1 to 5, wherein the hydrotrope is a water soluble salt of the toluene sulfonate. xylene sulfonate, cumene sulfonate or naphthalene sulfonate. 7. A composition as defined in claim 6. wherein the hydrotrope is cumene sulfonate. 8. A composition as defined in any one of claims 1 to 7, wherein the co-solvent is a lower alcohol, propylene glycol or polyethylene glycol. 9. A composition as defined in claim 8. wherein the co-solvent is propylene glycol. 10. A composition as defined in any one of claims 3 to 9. further comprising sufficient acid such that the composition, at use dilution, has a pH value of less than about 5. 11. A composition as defined in claim 10, wherein the SM/323C pH-value is between about 1.5 and about 5. 12. A composition as defined in claim 11. wherein the pH-value is between about 3 and about 5. 13. A composition as defined in any one of claims 10 to 12. wherein said acid is phosphoric acid, sulfamic acid, sulfuric acid, hydrochloric acid or a mixture of two or more thereof. 14. A composition as defined in claim 13, wherein said acid is phosphoric acid or sulfamic acid or a mixture thereof. 15. A method of treating water, which comprises adding to said water sufficient of a composition as defined in any one of claims 3 to 14 to achieve a concentration of available iodine of O.lppm to lOppm. SM/323C

Inventors: GLUCK BRUNO ANTHONY, GLUCK, BRUNO, ANTHONY
Applicants: GLUCK BRUNO A, GLUCK, BRUNO, ANTHONY
Application year: 1986
Main classification: C11D1
IPC codes: A01N59, C02F1, C11D1, C11D3