MXPA99004582A - Cleaning method for polyethylene terephtalate containers - Google Patents

Abstract

A method for cleaning polyethylene terephthalate containers including contacting the PET container with an alkaline wash solution having a temperature ranging of less than about 60°C is disclosed. The alkaline wash solution is formulated from a first concentrate, a second concentrate, an alkalinity source, and a balance of water. The first concentrate preferably has a first nonionic surfactant, a first builder, and acid in an amount effective to provide a phase stable solution. The second concentrate preferably has a second nonionic surfactant and a second builder. The first and second concentrate are present in the wash solution in a concentration ranging from about 0.3 wt.%to 2.0 wt.%. Preferably, the first nonionic surfactant has a cloud point ranging from about 5°C to 60°C.

Description

CLEANING METHOD FOR POLYETHYLENE TERTIFTHALATE CONTAINERS FIELD OF THE INVENTION The invention relates generally to methods and compositions for cleaning polyethylene terephthalate containers. More specifically, the invention relates to methods and compositions which remove mold, present in polyethylene terephthalate containers, with reduced fogging.

BACKGROUND OF THE INVENTION As in many industries, management of the economy has also affected the beverage industry and has resulted in some real changes in the way beverages are bottled, distributed and dispensed. In the last decade, the beverage industry has seen a change from glass to plastic containers. Plastic containers can be made of any number of materials depending on the application. One material is polyethylene terephthalate, "PET". Two types of PET bottles that are commonly used are returnable and non-returnable bottles. Non-returnable bottles are those that are filled, used and then discarded. Returnable bottles are collected and reused, and must be washed before refilling. PET bottles offer several advantages over glass. Its light weight reduces freight costs. When they fall on a hard surface they do not splinter like glass and generally do not break. The conveyor wear caused by the containers in the packing plant is also reduced. In addition, generally the closure can be reused after a bottle has been opened. The disadvantages are that PET bottles scratch easily, and are susceptible to chemical attack when washed. The containers of PET also does not tolerate conditions above 60 ° C. Exposing them to temperatures higher than 60 ° C causes deformation and / or shrinkage of the bottles. The recycling of PET containers was recently approved by the FDA in the United States, to allow the return of used containers in new ones. Because the new resin costs 50 to 75 cents per pound, recycling bottles is economically attractive. At the time, glass bottles of non-alcoholic beverages are expected to disappear from the market. This further increases the importance of the processing of PET containers. The cleaning of the PET bottles takes place over a series of steps using caustic immersion tanks and spray washing steps in a bottle washer. In the washing tanks, the product residue, soil, labels and labeling adhesive are removed. Because the surface of PET bottles is hydrophobic, cleaning them is more difficult than glass bottles. In addition, the lower wash temperature decreases the chemical activity of the bottle washing solution. The two main problems in the cleaning of PET bottles are mentioned by Laufenberg et al. , "Cleaning, Disinfecting, and Transporting Pet Returnables" (Cleaning, Disinfection and Transportation of PET Returns), Brew Bev. I nd. Int. 1, 40-4 (0 ref.) Energo, 1992. In this article, the author points out the susceptibility of PET bottles to corrosion or fogging. The fogging results from the chemical etching of the surface of the PET container by the caustic substance present in the wash bath. A particularly challenging problem, which affects reusable PET bottles, is the occurrence of mold in returned bottles. Simply discarding all the bottles from which mold can not be removed is prohibitively expensive. Rejection rates of 40 to 50% have occurred at certain times of the year in countries located in tropical climates. The cleaning temperature required for PET bottles is 60 ° C or lower due to the transition temperature of PET glass. If it is exceeded, the PET bottles deform and shrink. The cleaning power of a bottle washing solution at 60 ° C is only a quarter of that at 80 ° C. Returned bottles with product residue, that is, those bottles that have not been rinsed, are almost always contaminated with microbiological forms of life. The bottle washing solution eliminates the presence of microbiological forms of life, such as bacteria, spores, molds and yeasts present in the bottle. However, at the reduced temperature of 60 ° C, molds frequently present a persistent problem in the cleaning and re-use of PET bottles.

PET bottles simply can not be washed like glass. Glass bottles are usually washed at 80 ° C. The glass can also be washed with a relatively high concentration of caustic substance. Although glass can be washed with up to 5.0% caustic, as little as 1.5% caustic can cause fogging in a PET container. With the glass, the washing temperature, the concentration of the caustic substance, and the washing time can be adjusted to allow variability within the environment. In contrast, PET containers can not withstand high levels of any of these variables. Although various alternatives have been proposed, such as, decreasing the level of caustic substance, there is still a need in the industry for compositions and methods that permit efficient cleaning of PET containers and cases of multiple reuses.

BRIEF DESCRIPTION OF THE INVENTION The first aspect of the invention is a method for cleaning a polyeene terephthalate container. The method includes combining a first concentrate with a second concentrate in an alkaline wash solution. The first concentrate includes from about 0.3 to 25% by weight of a surfactant and from about 5 to 30% by weight of an acid. The second concentrate includes from about 8 to 60% by weight of an improver. The method further includes the step of contacting the PET container with the washing solution, where the removal of dirt is undertaken with minimal fogging of the container. A further aspect of the invention is a method for cleaning containers of polyeene terephthalate, which includes contacting the container with an alkaline washing solution having a temperature ranging from about 50 ° C to 60 ° C. The alkaline wash solution is formulated from a first concentrate, a second concentrate, a source of alkalinity and the rest of water. The first concentrate includes a nonionic surfactant, a first improver, an acid in an amount effective to provide a stable phase solution. The second concentrate includes a nonionic surfactant and a second improver. The first and second concentrates are present in the wash solution in a concentration ranging from about 0.5 wt% to 1.2 wt%, and the first non-ionic surfactant has a cloud point which varies from about 5 ° C to 60 ° C. A further aspect of the invention is an alkaline washing solution for cleaning polyeene terephthalate bottles. The wash solution includes from about 1 to 5% by weight of an alkalinity source, from about 480 to 4000 ppm of an improver, from about 6 to 500 ppm of a surfactant, and from about 20 to 800 ppm of a coupler. The invention includes compositions and methods for cleaning polyeene terephthalate (PET) bottles with intensified removal of mold and reduced fogging. In addition to the 1 to 3% caustic substance commonly used in PET bottle washing processes, the compositions of the invention include a combination of surfactants and improvers, which increases the cleaning and removes the mold. In general, the fogging results from chemical etching caused by the caustic substance present in the washing solution. The fogging is a clouding or dulling of the surface of the PET container, which detracts from the aesthetic character of the container. Surprisingly, it has been found that by using surfactants with appropriate cloud points, fogging can be substantially reduced. Preferably, the PET containers treated with the washing solution of the invention are substantially free of fogging. In addition, the growth of mold, particularly in the interior of PET bottles returned, proves to be a major challenge in bottle washing. Molds are very difficult to remove, even with a solution that has as much as 3% caustic. Good cleaning usually removes most of the organic components from the mold. However, inorganic mold residues may remain on the PET container surface. This can cause a problem similar to water spots. This condition provides a positive test result for staining with methylene blue, (Industrial Code of Practice for Refillable PET Bottles, Industrial Practice Code for returnable PET bottles), Edition 1 (1 993-1994 UNESDA / CESDA, pg. V-1 8) The compositions and methods of the invention substantially remove dirt and both organic and inorganic mold residue.

Detailed description of the invention The composition In general, the washing solution of the invention is formulated from two concentrate compositions. These two concentrate compositions are combined in an aqueous wash solution with an alkalinity source, before being used. These concentrate compositions generally comprise surfactants, an acid, enhancers such as sequestrants and quenching agents, coupling agents, and various other auxiliaries.

A. The surfactant system In general, the compositions of the invention comprise surfactants to facilitate cleaning of low foaming, and to avoid fogging of the PET container. Any number of surfactants can be used according to the invention, including nonionic surfactants, anionic surfactants, amphoteric surfactants and mixtures thereof. Nonionic surfactants encompass a wide variety of polymeric compounds, which include, but are not limited to, ethoxylated alkylphenols, ethoxylated aliphatic alcohols, ethoxylated acids, ethoxylated ether amines, carboxylic esters, carboxylic amides, and oxide block copolymers. of polyoxyalkylene. Preferably, nonionic surfactants are used in the invention, such as those comprising portions of ethylene oxide, portions of propylene oxide, as well as mixtures thereof, and portions of ethylene oxide-propylene oxide either in formation block or heteric. Further useful in the invention are nonionic surfactants comprising alkyl ethylene oxide compounds, propylene oxide-ethylene alkyl oxide compounds and butylene oxide-ethylene oxide alkyl compounds, as well as mixtures thereof. The ethylene oxide-propylene oxide portion and the ethylene oxide-butylene oxide portion may be either in block or heteric formation. Also useful in the invention are nonionic surfactants having any combination mixture of ethylene oxide-propylene oxide portions linked to an alkyl chain, where the ethylene oxide and propylene oxide portions may be in a random pattern. u ordered and of any specific length. The nonionic surfactants useful in the invention may also comprise random sections of ethylene oxide-butylene oxide, or ethylene oxide-block or heteric propylene oxide. Preferred nonionic surfactants include alkylphenols, ethoxylated alcohols, and block copolymers of ethylene oxide and propylene oxide. Examples of nonionic surfactants found useful in the invention include block copolymers of (EO) / (PO), having at least about 3 moles of (EO) and at least about 15 moles of (PO); aryl or aliphatic ethoxylates, having at least about 3 moles of (EO), which may or may not be capped with methyl, butyl or benzyl portions; aryl ethoxylate-propoxylate or aliphatic copolymers, having at least about 2 moles of (EO) and from about 4 moles of (PO) and which may also be capped with methyl, butyl or benzyl; and copolymers of aryl or aliphatic ethoxylate-butoxylate, having at least about 2 moles of (EO) and about 4 moles of (BO), and which may also be capped with methyl, butyl or benzyl. The aliphatic group can comprise any linear portion of C8-C24. The aryl group may generally comprise aromatic structures, such as benzyl. A HLB value of 4 to 1 3 can also be used to characterize surfactants useful in the invention. Representative nonionics, which are useful in the invention include EO / PO block copolymers available from Henkel KgaA; Pluronic L62 and L44, which are block copolymers of EO / PO available from BASF; Tergitol 1 5-S-3, TMN3, TM N 1 0, which are alcohol ethoxylates available from Union Carbide; Surfonic L24-1 .3, which is a linear ethoxylated alcohol available from Texaco Chemical Co.; ethoxylates of nonyl phenol, such as NPE 4.5, N PE 9, and Surfonic N 120 available from Texaco Chemical Co.; ethoxylated alkyl amines, such as, ethoxylated coconut amine available from Sherex Chemical Co. as Varonic K-215; an alkyl ethoxylated carboxylic acid, such as, Neodex 23-4; and benzylated alcohol ethoxylates and EO / PO block copolymers among other nonionic surfactants. Also useful in the invention are low foaming surfactants, which can be defatted from the wash solution at a temperature of 59 ° C or less. Preferably, the surfactant system comprises surfactants having a cloud point of from about 5 ° C to 60 ° C, preferably from about 10 ° C to 50 ° C, and most preferably from about 10 to 20 ° C, so that In the alkaline wash solution, the surfactants will be degreased or formed into a film and deposited on the PET container surface, providing protection against fogging. A preferred line of surfactants includes Dehypon LT104, which is a fatty alcohol of C1 2.1 8 (EO) 1 0 capped with butyl and LS24, which is a fatty alcohol of C1 2-1 4 ((EO) 2 (PO) 4), both available from Henkel Canada Ltd. Anionic surfactants can also be used in the invention. The commercially available, normal anionic surfactants provide either a carboxylate, sulfonate, sulfate or phosphate group as the functional anion. We have found that carboxylate-based anionic surfactants, such as ethoxylated alcohol carboxylates, reduce fogging of the container. A commercial source of this type of surfactant is Neodox 23-4M R available from Shell Chemical Co. Amphoteric surfactants can also be used in the invention. Such amphoteric surfactants include betaine surfactants, sulfobetaine surfactants, sarcosinate surfactants, amphoteric imidazolinium derivatives and others. Certain surfactants found useful in reducing fogging include sarcosine / cocoyl and lauroyl sarcosinates, such as Hamposyl C and L available from Hampshire Chemical Co.

B. Acid The composition of the invention may also comprise an acid source. The acid functions stabilize the surfactant system, so that before mixing in the wash solution, the concentrate is a true stable phase solution. Once added to the alkaline washing solution, the acids are neutralized, become salts, and provide increased cleaning efficiency and retard scale formation in the components of the washing machine. Generally, the acid can be any number of organic or inorganic acids. Inorganic acids useful in the composition of the invention include phosphoric acid, polyphosphoric acid or acid pyrophosphate salts, among others. Organic acids useful in the invention include mono and polycarboxylic acids, such as acetic acid, hydroxyacetic acid, citric acid, gluconic acid, glucoheptanoic acid, lactic acid, succinic acid, malonic acid, glutaric acid, and mixtures thereof.

C. Means The composition of the invention may also comprise an enhancer. The enhancers, ie, sequestrants and chelating agents, retard the precipitation of flakes on the side walls of the PET container and the bottle washing machine. The improvers also facilitate the suspension of dirt, bind ions of hardness and, in turn, intensify the cleaning during the washing process. According to one embodiment of the invention, the first concentrate may contain a first enhancer and the second concentrate may contain a second improver. The enhancers that can be used according to the invention include sequestrants, such as, phosphonates, phosphinates, acrylates and polyacrylates, and polycarboxylates, among others. Maleate polymers and maleate and acrylate copolymers are also useful improvers; salts, such as, polyaspartic and polyglutaric acid salts; erythorbic acid, polyacrylamidopropyl sulfonate; and phosphinocarboxylic acid, among others.

Water-soluble acrylic polymers that can be used include polyacrylic acid, polymethacrylic acid, copolymers of acrylic acid-methacrylic acid, hydrolyzed polyacrylamide, hydrolyzed methacrylamide, hydrolyzed acrylamide-methacrylamide copolymers, and mixtures thereof. Water soluble salts or partial salts of these polymers can also be used, such as, their respective alkali metal salts (eg, sodium or potassium) or ammonium. Phosphonic acids and salts of phosphonic acid are also useful as builders. Such useful phosphonic acids include mono, di, tri, tetra and penta phosphonic acids, which may contain groups capable of forming anions under alkaline conditions.

The phosphonic acid may also comprise a phosphonopolycarboxylic acid of lower molecular weight, such as, one having about 2-4 carboxylic portions and about 1 to 5 phosphonic acid groups. Such acids include 1-phosphono-1-methyl-succinic acid, phosphonosuccinic acid and 2-phosphonobutane-1, 2,4-tricarboxylic acid. Preferred sequestrants include Dequest® sequestrants available from Monsanto Co., including Dequest 2006®, which is a pentasodic salt of amino tri (methylene phosphonic acid); Dequest 201 0®, which is 1-hydroxyethylidene-1,1-diphosphonic acid; Bayhibit AM® available from Mobay Chemical Co., which is 2-phosphonobutane-1, 2,4-tricarboxylic acid; Dequest 2000®, which is aminotri (methylene phosphonic acid); and Belsperse 161 ® by Ciba Geigy, which is a phosphino polycarboxylic acid. The improver present in any concentrate can also be a chelating agent. Unlike a sequestrant, the chelating agent tends to bind alkaline earth metals present in the wash solution and hold these compounds in solution. It is believed that mold uses the organic portion of nutrients leaving behind inorganic salts. As a result, the ineffective removal of mold is indicated, frequently, by inorganic salts which are left behind on the surface of the PET container. The chelating agent removes these inorganic salts that are found under the mold. The number of ligatures capable of being formed by a chelating agent on a single hardness ion is reflected by marking the chelating agent as bidentate (2), tridentate (3), tetradentate (4), etc. Any number of chelating agents according to the invention can be used. Representative chelating agents include salts of amino carboxylic acids, salts of phosphonic acid, water-soluble acrylic polymers, among others. Suitable amino carboxylic acid chelating agents include N-hydroxyethyliminodiacetic acid, nitrilotriacetic acid (NTA), ethylenediaminetetraacetic acid (EDTA), N-hydroxyethyl-ethylenediaminetriacetic acid (HEDTA), and diethylenetriaminepentaacetic acid (DTPA), as well as isoserine-N acid, N-diacetic, beta alanine N, N-diacetic acid, sodium glycolate, and tripolyphosphate, among others. According to a useful aspect of the invention, the second enhancer present in the second concentrate comprises an amino carboxylic acid chelating agent, preferably ethylenediaminetetraacetic acid or salts thereof.

D. Couplers The composition of the invention may also include a coupling agent. The coupling agent functions to stabilize the concentrate composition, so that it is a true stable phase solution. For this purpose, any number of organic coupling agents can be used, including sulfates, sulfonates as well as monofunctional and polyfunctional alcohols. Preferred coupling agents include sulphonate and sulfate compounds, such as sodium xylene sulfonate, sodium eumenium sulfonate, sodium toluene sulfonate, 2-ethylhexyl sulfate, alkyl diphenyl oxide disulfonate, where the alkyl group is either Branched C12 or linear C10, sodium alkyl naphthalene sulfonate, and sodium octane sulfonate and disulfonate, and mixtures thereof. Those coupling agents, which have been found useful, include linear alkylalcohols such as, for example, ethanol, isopropanol and the like. Also useful are polyfunctional hydroxy compounds, such as alkylene glycols, such as hexylene glycol and propylene glycol; phosphate esters including Gafac RP71 0 from Rhone-Poulence Chemicals, and Triton H-66 from Rohm & Hass Co.

E. Auxiliary The compositions and methods of the invention can use any number of other auxiliaries, such as defoamers of added nonionic surfactants, such as those described in US Pat. 5, 516,451 for Schm itt et al. , which is incorporated herein by reference. Trace compounds, such as potassium iodide, dyes and dyes, fragrances and preservatives, among other constituents, are also useful in the invention.

The method of use The method of the invention provides increased cleaning efficiency of PET containers, removing dirt, inorganic salts, and molds, while delaying fogging of containers. This result is obtained by formulating a first acid concentrate with a high concentration of surfactant and a second concentrate separately having a high concentration of improver.

According to one aspect of the invention, the first and second concentrates may be incompatible if they are mixed separately from a washing solution. The incompatibility in this context comes from different pH requirements of the two different concentrates. The first concentrate may generally have an acidic pH of less than about 2 to maintain the solubility of the surfactant system. The pH of the second concentrate is selected to provide complete solubility of the improver and is generally alkaline. The combination of the two concentrates before dilution in the wash solution can result in phase separation of the surfactant system or the enhancer depending on the pH. In use, the two concentrates are combined in an alkaline washing system to provide increased cleaning efficiency with good improving efficiency. Illustrative concentration ranges for each of the two concentrates are given below: TABLE 1 Concentration (% by weight) Concentrate 1 Preferred Useful MOST preferred Surface-active system 0.3-25 1 -1 5 3-1 0 First improver 0-20 5-20 10-20 Coupling 1 -40 30-20 5-1 5 Acid (100% w / w) 5-30 1 0-20 10- 15 Water qs q.s. q.s.

Concentrate 2 Surfactant system 0-10 0. 1 -1 5 0.1 -1 Second improver 8-60 1 5-45 30-45 Water q.s. q.s. q.s.

Solution of use (ppm) Surfactant 6-500 20-300 60-200 Improver 480-4000 1000-3000 2000-3000 Coupling agent 20-800 60-400 1 00-300 In use, this system is diluted in a wash solution ranging from about 0.1% by weight to 0.8% by weight, preferably from about 0.2% by weight to 0.3% by weight of the first concentrate and from about 0.2 to 1.2% by weight. by weight, and preferably from about 0.4% by weight to 0.8% by weight of the second concentrate. The ratio of the first concentrate to the second concentrate in the alkaline wash solution, generally ranges from about 0.1: 0.5 to 0.1: 1.0, and preferably from about 0. 1: 0.2 to 0.1 5: 0.3. Generally, the alkaline wash solution can have a total of from about 0.3 to 2.0% by weight and preferably from about 0.5 to 1.2% by weight of both the concentrate 1 and the concentrate 2. According to a preferred aspect of the invention, the wash solution comprises at least about 1000 ppm of EDTA, at least about 5 ppm of a phosphonate compound, and at least about 1000 ppm of a gluconate compound. The washing of PET containers generally takes place over a number of steps. The PET containers are emptied and pre-cleaned, and then they are soaked in the washing solution. The washing solution generally ranges from 1.0% by weight to 5% by weight, and preferably from 1.5% by weight to 3% by weight of caustic (NaOH). In this system Concentrate 1 and Concentrate 2 are mixed in which the PET containers are applied. The washing tends to take place over a period, which varies from about 7 to 20 minutes. The washing temperature is approximately 59 ° C + 1 ° C. The containers then pass through a weak caustic substance stage, where water is run in the tank to continue the cleaning and the rinsing begins by reducing the concentration of sodium hydroxide. The concentration of caustic substance can be maintained by a conductivity controller. The containers then pass through at least three rinse steps, which rinse the containers sequentially with hot water and cold water. The final rinse takes place with potable water, after which the containers are put face up, inspected and filled.

EXAMPLES The following working examples provide a non-limiting illustration of the invention.

WORK EXAMPLE 1 The fogging was studied using various compositions as detailed. Next, Table 2 provides examples which were tested along with other compositions in Table 3.

TABLE 2 COMPOSITIONS EXAMPLE 1A EXAMPLE 1B H3PO4 (75% w / w) 10.00 Gluconic acid (50% w / w) 10.00 Dehypon LT-104 11.00 (C? 2-i8H24-37 (EO)? OOnC H9) Dehypon LS-24 5.00 (C12.14H25.29 (EO) 2 (PO) 4OH) Triton BG-10 1.00 (alkyl polyglucoside) Dequest 2000® (50% w / w) 6.00 6.00 (amino-trimethylene phosphonic acid) Dequest 2010 (60% w / w) 2.00 (1-hydroethylidene-1,1-disphosphonic acid) Bayhibit-AM® (50% w / w) 3.00 (2-phosphonobutane-1,2 acid) 4-tricarboxylic acid tetrasodium salt 39.00 ethylenediaminetetraacetic acid (powder) Sodium eulium sulfonate 30.00 (40% w / w) VN-11 0.50 (diethylene glycol oleyl alcohol) Potassium iodide 0.25 Chemical fogging was studied with PET strips (1 .27 cm x 5.08 cm), which were cut from amorphous PET sheets (low crystallinity). The strips were immersed in approximately 200 ml of 2.8% caustic solutions containing various amounts of additives being tested. The solutions were stirred at 100 rpm in a water bath with a temperature maintained between 58-60 ° C for 24-72 hours. The degree of fogging / corrosion was evaluated visually and gravimetrically using water (fogging rating of 0) and a 2.8% caustic solution (fogging rating of 10) as references.

TABLE 3 ACTIVE EXAMPLE CONCENTRATION EMPAÑA -MIENTO 1A Table 2 0.05% by weight 0.5 1A Table 2 0.2% by weight 0.5 1A Table 2 0.6% by weight 0.5 1A Table 2 2.0% by weight 0.5 1B Table 2 0.05% by weight 10 1B Table 2 0.1% by weight 7.5 1B Table 2 0.2% by weight 5.5 1B Table 2 0.35% by weight 1.5 1 Dehypon LT104 (d2.18 10 ppm 0 H24-37 (EO)? OOnC4H9) 1D Dehypon LS-24 (C? 2-4 10 ppm H25-29 (EO) 2 (PO) 4OH) 1E Triton BG-10 ( polyglucoside 300 ppm alkyl (70% w / w) 1F Glucopon 600 500 ppm 10 (alkyl polyglucoside (C? 28H276O (C6H10? 5) o.3H)) 1G Sodium eumenium sulfonate 300 ppm 9 Control 1 Water 0% by weight 0 Control 2 Caustic substance 2.8% by weight 10 The fogging was measured against a scale of 0 for no fogging, such as with water, and 10 for 2.8% of substance caustic Examples 1 C and 1 D, as well as the series of runs run in Example 1A proved that these compositions are very effective in preventing fogging, either alone or in conjunction with sequestrants.

WORK EXAMPLE 2 A second fogging analysis was performed using the method of Example 1 with 100 ppm of each active (EJ.2A-2W), and 2.8% by weight of NaOH in the wash water (except for the control); the results are reported in Table 4.

TABLE 4 ACTIVE EXAMPLE BINDING 2A (PO) 24 (EO), 5 [(PO) 13.o (EO) 15.5] (EO) 15 (PO) 24 0 2B (PO) 13 (EO) 15 [(EO) 2.2 (PO) 25.5] (EO) 15 (PO) 13 0 2C (PO) 5 (EO)? 5 [(PO), 3 Q (EO), 55] (EO)? 5 (PO) 24 1 2D Pluronic L62 0 HO (EO) 11 (PO) 30 (EO) 8H 2E Pluronic L44 0 HOEEOJntPO EOJnH 2F Tergitol 15-S-3 0 (C11.15H23.3i (EO) 3OH) 2G Tergitol TMN 3 0 C? 2H25 (EO) 3OH 2H Tergitol TMN 10 0 C? 2H25 (EO) 10OH 1 Surfonic L24-1.3 0 (C12-14 (EO) 1 3OH) J Plurafac LF131 15 (C127 (EO) 7 (BO) 1 7OCH3) K Dehypon LT104 0 (C? 2-? 8H24.37 (EO)? OOnC4H9) L (C6H5CH2) - (PO) 13 (EO) 15 [(EO) 2.2 / (PO) 25.5] 0 (EO) 15 (PO) 13- (CH2C6H5) M C12.14O (EO) 10-? 2-CH2-C6H5 0 N NPE 4.5 2 nonyl phenol (EO) 5 20 NPE 9.5 nonyl phenol (EO) 9 5 2P Surfonic N 1 20 C9H 19C6H4 (EO) 12OH 2Q Neodox 23-4 (C ? 2-? 3 (EO) 4OCH2COOH) 2R Varonic K215 (cocoamine ethoxylate (EO) 1 5) 2S Hamposyl C Coco sarcosine (C12-? 8H25-37C (O) N (CH3) CH2COOH) 2T Hamposyl L Lauroyl sarcosine 2U Hamposyl L30 10 Lauroyl sarcosinate sodium 2V Silwet L77 (CH3) 3SiOSi [(CH3) OSi (SH3) 3] [(CH2) 3 (EO) 8OCH3] 2W 2.8% NaOH ol) 1 0 WORK EXAMPLE 3 Dirty bottles were cut from the field in test panels (sparely 5.08 cm x 7.62 cm). A wash test was carried out in 1 000 ml of solution with stirring (500 rpm) for 10 min. , followed by 1 min of rinsing with water (atomization with nozzle of 0.5624 kg / cm2, with the top part down). Stained with methylene blue was used to evaluate the level of soiling both before and after cleaning according to the Industrial Code of Practice for Refillable Pet Bottles, edition 1 (1993-1994 UNESDA / CESDA), page V-18. The previous steps were repeated every 10 minutes for the cleaning iterations of 20 minutes and 30 minutes. The wash solution comprised 2.8% by weight of caustic substance, 0.6% by weight of Example 1 B, and the variant amounts of Example 1 A as shown in Table 5A below. The data in quadruplicate was used for a statistical average. The data was reported as total cleaned / total washed.

TABLE 5A 2.8% caustic 0.6% of Example 1 B Cleaning time Example 1A (% by weight) 10 min 20 min 30 min 0.05 1/4 1/4 2/4 0.10 1/4 2/4 2/4 0.15 2/4 3/4 3/4 0.20 2/4 2/4 3/4 0.25 3/4 3/4 3/4 0.30 4/4 TABLE 5B In this example, the wash solution comprised 2.8% by weight of caustic and 0.2% by weight of Example 1 A, with varying amounts of Example 1 B, as indicated below. The data was reported as in Table 5A.

Cleaning time Example 1 B (% by weight) 1 0 min 20 min 30 min 0.60 2/4 2/4 2/4 1 .20 4/4 0.80 4/4 TABLE 5C Different concentrations of Example 1 A and 1 B were combined to test the cleaning efficiency. The data was reported as in Tables 5A and 5B.

Cleaning time Example 1 A Example 1 B (% by weight) (% by weight) 10 min 20 min 30 min 0.10 1.20 3/4 3/4 3/4 0.15 1.20 3/4 3/4 3/4 0.20 1.20 4 / 4 0.10 1.80 3/4 3/4 3/4 0.15 1.80 3/4 4/4 0.20 1.80 4/4 0.20 0.7 2/4 2/4 3/4 0.20 0.8 2/4 2/4 3/4 0.20 1.0 4/4 0.60 0.4 2/4 2/4 2/4 0.40 0.4 2/4 2/4 2/4 TABLE 5D The cleaning efficacy of the washing solutions, having established the concentrations of Example 1 A and Example 1 B with varying concentrations of caustic, was then analyzed. Example 1A was added 0.2 wt% to the wash solution and Example 1 B was added to 0.8 wt% to the wash solution. The results are reported below in the same manner as Tables 5A-5C.

Cleaning time Caustic substance (% by weight) 1 0 min 20 min 30 min 1 .5 2/4 2/4 3/4 2.0 2/4 2/4 4/4 2.6 3/4 3/4 4/4 The above specification, examples and data provide a complete description of the manufacture and use of the composition of the invention. Since many embodiments of the invention can be made without departing from the spirit and scope of the invention, the invention resides in the appended claims hereinafter.

Claims (38)

1. CLAIMS 1 . A method for cleaning a polyethylene terephthalate container, said method comprising the steps of: combining a first concentrate with a second concentrate in an alkaline washing solution (a) comprising said first concentrate: (i) from about 0.3 to 25% by weight weight of a surfactant; and (ii) from about 5 to 30% by weight of an acid; (b) said second concentrate comprising: (i) from about 8 to 60% by weight of an improver; said method further comprising the step of contacting said container with said washing solution, wherein the removal of dirt is undertaken with minimal fogging of the container.
2. 2. A method for cleaning polyethylene terephthalate containers, said method comprising the steps of contacting the container with an alkaline washing solution, having a temperature ranging from about 50 ° C to 60 ° C, said alkaline washing solution it is formulated from a first concentrate, a second concentrate, a source of alkalinity, and the rest of water; (a) said first concentrate comprising a nonionic surfactant, a first improver, an acid in an amount effective to provide a stable phase solution; and (b) said second concentrate comprising a nonionic surfactant, and a second improver, wherein said first and second concentrates are present in the wash solution in a concentration ranging from about 0.3 wt% to 2.0 wt%, having said first nonionic surfactant a turbidity point ranging from about 25 ° C to 60 ° C. The method of claim 1, wherein said first concentrate comprises a first improver and said second concentrate comprises a second enhancer. 4. The method of claim 1, wherein said second concentrate further comprises a surfactant. The method of claim 1 or 2, wherein the concentration of the first concentrate added to said wash solution ranges from about 0.1% by weight to 0.8% by weight of the wash solution. The method of claim 1 or 2, wherein the concentration of the second concentrate added to the wash solution ranges from about 0.2 wt% to 1.2 wt% of the wash solution. The method of claim 5 or 6, wherein the ratio of the first concentrate to the second concentrate in the wash solution ranges from about 0.1: 0.5 to 0.1: 1.0. The method of claim 1 or 2, wherein the wash solution comprises from about 0.3% by weight to 2.0% by weight of said first and second concentrates. 9. The method of re-excitation 1 or 2, wherein the alkaline wash solution comprises from about 1% by weight to 5% by weight of an alkalinity source. The method of claim 9, wherein said source of alkalinity comprises about 1.5% by weight to 3% by weight of caustic substance. eleven . The method of claim 1 or 2, wherein said first concentrate further comprises a coupler. The method of claim 1, wherein said coupler is selected from the group consisting of sodium xylene sulfonate, sodium sulfate, 2-ethyl hexyl, sodium eumeno sulfonate, sodium toluene sulfonate, sodium alkyl naphthalene sulfonate, sodium octane sulfonate, a branched alkyl diphenyl oxide disulfonate, a linear alkyl diphenyl disulfonate, and mixtures thereof. The method of claim 1, wherein said coupler comprises a polyfunctional hydroxy compound. The method of claim 1, wherein said coupler comprises a phosphite ester. 15. The method of claim 1 or 2, wherein said wash solution has a temperature of from about 50 to 70 ° C. 16. The method of claim 1 or 2, wherein said wash solution has a temperature of less than about 60 ° C. The method of claim 1 or 2, wherein said surfactant is selected from the group consisting of a nonionic surfactant, an anionic surfactant, an amphoteric surfactant, and mixtures thereof. 18. The method of claim 1 or 2, wherein said surfactant comprises a nonionic surfactant. The method of claim 18, wherein said nonionic surfactant is selected from the group consisting of a block copolymer of ethylene oxide-propylene oxide, an alkyl ethoxylate, an alkyl propoxylate-ethoxylate, a butoxylate- alkyl ethoxylate, and mixtures thereof. The method of claim 3, wherein said first improver is selected from the group consisting of phosphonates, phosphinates, acrylates, polycarboxylates, and mixtures thereof. The method of claim 3, wherein said second enhancer comprises a chelating agent of ethylenediaminetetraacetic acid or a salt thereof. 22. The method of claim 3, wherein said second concentrate is not compatible with said first concentrate. 23. The method of claim 22, wherein said second enhancer comprises a salt of alkylene polyamino polyacetic acid. The method of claim 1, wherein said acid is selected from the group consisting of an organic acid, an inorganic acid, and mixtures thereof. The method of claim 24, wherein said acid comprises an organic acid selected from the group consisting of citric acid, acetic acid, hydroxy acetic acid, gluconic acid, glucoheptanoic acid, lactic acid, and mixtures thereof. 26. The method of claim 18, wherein said nonionic surfactant has a cloud point in the alkaline wash solution, ranging from about 5 ° C to 60 ° C. 27. The method of claim 1 or 2, wherein after washing said polyethylene terephthalate container is free from mold. 28. A wash solution resulting from the method of claim 1 or 2, said wash solution comprising from about 6 to 500 ppm of surfactant, from about 480 to 4000 ppm of improver, and from about 20 to 800 ppm of coupling agent . 29. The method of claim 1 or 2, wherein (a) said first concentrate comprises (i) from about 1 to 15% by weight of said first nonionic surfactant; (ii) from about 5 to 20% by weight of said first improver; and (iii) from about 10 to 20% by weight of said acid; and (b) said second concentrate comprises (i) from about 0.1 to 5% by weight of said second nonionic surfactant; and (ii) from about 15 to 45% of said second improver. 30. A wash solution resulting from the method of claim 1 or 2, said wash solution comprising from about 6 to about 500 ppm of surfactant, at least about 5 ppm of said first improver, said first improver comprising a phosphonate compound, and at least about 1000 ppm of said second improver, said second enhancer comprising ethylenediaminetetraacetic acid or a salt thereof. 31 An alkaline wash solution for cleaning polyethylene terephthalate bottles, said wash solution comprising a mixture of: (a) from about 1 to 5% by weight of an alkalinity source; (b) from about 480 to 4000 ppm of an improver; (c) from about 6 to 500 ppm of a surfactant; and (d) from about 20 to 800 ppm of a coupler, said coupler being selected from the group consisting of a sulfonate compound, a disulfonate compound and mixtures thereof. 32. The wash solution of claim 31, wherein the alkaline wash solution comprises from about 1.5% by weight to 3% by weight of an alkalinity source. 33. The washing solution of claim 31, wherein said coupler is selected from the group consisting of sodium xylene sulfonate, 2-ethylhexyl sulfate, sodium eumeno sulphonate, sodium toluene sulfonate, sodium alkyl naphthalene sulfonate, its sodium octane lphonate, a branched alkyl diphenyl oxide disulfonate, a linear alkyl diphenyl oxide disulfonate, and mixtures thereof. 34. The washing solution of claim 31, wherein said surfactant comprises a nonionic surfactant. 35. The washing solution of claim 34, wherein said nonionic surfactant is selected from the group consisting of a block copolymer of ethylene oxide-propylene oxide, an alkyl ethoxylate, an alkyl propoxylate-ethoxylate, a butoxylate-ethoxylate of alkyl, and mixtures thereof. 36. The wash solution of claim 31, wherein said improver is selected from the group consisting of phosphonates, phosphinates, acrylates, polycarboxylates, and mixtures thereof. 37. The washing solution of claim 31, wherein said improver comprises ethylenediaminetetraacetic acid or a salt thereof. 38. The wash solution of claim 31, comprising at least about 1000 ppm of ethylenediaminetetraacetic acid or salt thereof, of at least about 5 ppm of a phosphonate compound, and at least about 100 ppm of a gluconate compound.