NZ335914A - Cleaning method for polyethylene terephthalate containers using an alkaline wash solution - Google Patents

Cleaning method for polyethylene terephthalate containers using an alkaline wash solution

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Publication number
NZ335914A
NZ335914A NZ335914A NZ33591496A NZ335914A NZ 335914 A NZ335914 A NZ 335914A NZ 335914 A NZ335914 A NZ 335914A NZ 33591496 A NZ33591496 A NZ 33591496A NZ 335914 A NZ335914 A NZ 335914A
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NZ
New Zealand
Prior art keywords
wash solution
concentrate
builder
acid
surfactant
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Application number
NZ335914A
Inventor
Bruce R Cords
Gerald K Wichmann
Guang-Jong Jason Wei
David D Mcsherry
Brendon L Herdt
Arturo Valencia
Original Assignee
Ecolab Inc
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Publication date
Application filed by Ecolab Inc filed Critical Ecolab Inc
Priority to NZ335914A priority Critical patent/NZ335914A/en
Priority claimed from PCT/US1996/018261 external-priority patent/WO1998022566A1/en
Publication of NZ335914A publication Critical patent/NZ335914A/en

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Description

New Zealand Paient Spedficaiion for Paient Number 335914 New Zealand No 335914 International No PCT/US96/18261 TO BE ENTERED AFTER ACCEPTANCE AND PUBLICATION Priority dates 15 11 1996 Complete Specification Filed 1511 1996 Classification (6) 01103/20,33,36,60, B08B3/10, B08B9/08 Publication date 28 October 1999 Journal No 1445 SMO DRAWINGS NEW ZEALAND PATENTS ACT 1953 COMPLETE SPECIFICATION Title of Invention Cleaning method for polyethylene terephthalate containers Name address and nationality of apphcant(s) as in international application form ECOLAB INC , Ecolab Center, St Paul, Minnesota 55102, United States of America 1 PCT7US96/18261 CLEANFNfl METHOD FOR POLYETHYLENE TEREPHTHALATE 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 on polyethylene terephthalate containers, with reduced ha7ing Background of the Invention As with many industries, the drive towards economy hasalso effecied the beverage industry and has resulted in ccrtain n al changes in the way in which beverages are bottled, distributed and dispensed In the last decade the beverage industry has seen a switch from glass to plastic containers Plastic containers may be made from any 1 5 number of materials depending on the application One material is polyethylene terephthalate, "PE P 1 wo types of PET bottles that aie commonly used are single trip and multi-trip bottles Single trip bottles are those which are filled, used, and then discarded Multi-trip bottles arc collected and reused and must be washed before refilling PET bottles offer several advantages over gldis Their light weight reduccs ireight costs When dropped onto a hard surface they do not shatter like glass and generally do not break Conveyor wear caused by the containers in the packaging plant i<; also reduced "1 he closure is also generally reusable after a bottle has been opened Disadvantages are that PET bottles are easily scratched, and susceptible to 25 ehemicdl attack when they arc washed PFT containers also do not tolerate conditions above 60°C Exposing them to higher temperatures than 60°C causes deformation and/or shrinkage of the bottles Recycling of PET containers was recently approved by the FDA in the USA to permit turning used containers into new ones Because new resin costs 50 to 75 cents 30 per pound, recycling used bottles is economically attractive In time, glass soft drink bottles are expected to disappear from the market This heightens the relevance of PET container processing even further The cleaning of PEl bottles takes place over a series of steps using caustic immersion tanks and spray wash stages in a bottlewasher In the wash tanks, product 35 residue, dirt, labels and labeling adhesive are removed Because the surface of PET bottles is hydrophobic, cleaning them is more difficult than glass bottles Also, the lower washing temperature decreases the chemical activity of the bottlewashing solution Print-ed ftom Mimosa WO 98/22566 PCT/I1S96/18261 2 Two principle problems m the cleaning of PET bottles are touched on by Laufenberg et al, "Cleaning Disinfecting, and Transporting Pet Returnable1:", Brew Bev Ind Int 1, 40-4 (0 ref) January, 1992 In this article, the author outlines the susceptibility of the PET bottles to 5 corrosion or hazing Hazing results from the chemical etching of the surface of the PET container by the caustic present in the wash bath An especially challenging problem whieh affects reusable PEI bottles is the occurrence of mold in returned bottles To simply discard all bottles from which mold can not be removed is prohibitively expensive Reject rates of 40 to 50% have occurred 10 at certain times oi the year in countries located in tropical chmatcs The necessary cleaning temperature for PET bottles is 60nC or less due to the glass transition temperature of PET If exceeded, PEI bottles deform and shrink The cleaning power of a bottlewashing solution at 60°C is only one quarter that at 80°C Bottles returned with product residue, l e, those bottles that have not been rinsed, are 15 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 piesent in the bottle However, at the rcduced temperature of 60°C, molds often present a persistent problem in the cleaning and reuse of PET bottles PET bottles simply cannot be washed like glass Glass bottles are normally 20 washed at 80°C Glass can also be washed with a relatively high concentration of caustic While glass may be washed with up to 5 0% caustic, as little as 1 5% caustic can cause ha/ing in a PET container With glass the washing temperature, the caustic concentration, and the washing time may be adjusted to allow for variability within the environment In contrast, PET containers cannot withstand high levels of any of these 25 variables While various alternatives have been proposed such as lowering the level of caustic, there remains a need in the industry for compositions and methods which allow for the efficient cleaning of PET contauiers and multiple reuse events Summary of the Invention The first aspcct of the invention is a method for cleaning a polyethylene terephthalate container The method includes combining a first concentrate with a second conccntratc in an alkaline wash solution The first conccntrate includes from about 0 3 to 25 wt-% of a surfactant and from about 5 to 30 wt-% of tin acid The 35 second concentrate includes from about 8 to 60 wt-% of a buildei The method further includes the step ot contacting the PE f container with the wash solution wherein the removal of soil is undertaken with minimal having of the container Printed From Mimosa WO 98/22566 PCT/US96/18261 3 /} An additional aspect of the invention is a method for cleaning plolyethylene terephthalate containers which includes contacting the container with an alkaline wash 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, an alkalinity source, and a balance of water The first concentrate includes a nonionic surfactant, a first builder, and acid in an amount effective to provide a phase stable solution The second concentrate includes a nonionic surfactant and a second builder The first and second concentmte aie present in the wash solution in a total concentration ranging from about 0 3 wt-% to 2 0 wt-% and the fust nonionic surfactant has a cloud point ranging lrom about 5°C to 60°C A lurther aspect of the invention is an alkaline wash solution toi cleaning polyethylene terephthalate bottles The wash solution irom about 1 to 5 wt-% of a source ol alkalinity, lrom about 4S0 to 4000 ppm of a builder fiom about 6 to 500 ppm of a suifactanl and liom about 20 to 800 ppm of a coupler said coupler selected ftom the gioup consistinu ol a sullonate compound, a disulfonate compound a sulfate compound and nuxtuies thereof < A further aspect of the invention is an alkaline wash solution for cleaning polyethylene terephthalate bottles The wash solution includes from about 1 to 5 wt-% of a source of alkalinity, from about 480 to 4000 ppm of a builder, from about 6 to 500 ppm of a surfactant, and from about 20 to 800 ppm of a coupler The invention is compositions and methods for cleaning polyethylene terephthalate (PET) bottles with enhanced removal of mold and reduced hazing In addition to the 1 to 3 wt-% caustic commonly used in PET bottle washing procedures, the compositions of the invention include surfactants and builder combination, which heightens cleaning and removes mold Hazing generally results from chemical etching caused by caustic present m the wash solution Hazing is a clouding or dulling of the PET container surface which detracts from the aesthetic character of the container Surprisingly, it has been found that by using surfactants with appropriate cloud points, hazing may be substantially rcduced Preferably, PET containers treated with the wash solution of the invention are substantially free of hazing Further, mold growth, particularly m the inside of returned PET bottles, proves to be a major challenge in bottle washing Molds are very difficult to remove, even with a solution having as much as 3% caustic Good cleaning usually removes most of the organic components of mold However, the inorganic residues of mold may remain on the PET container surface This may cause a problem similar to water spots This condition gives a positive test result by methylene blue staining, (Industrial Code of Practice for Refillable PET Bottles, Edition 1 (1993-1994 UNESDA/CESDA, pg V-18) The compositions and methods of the invention substantially remove soils and both the organic and inorganic residues of mold WO 98/22S66 PCT/US96/18261 4 Detailed Description of the Invention The Composition Generally, the wash solution of the invention is formulated from two concentrate 5 compositions These two concentrate compositions are combined in an aqueous wash solution with an alkalinity source, before use These concentrate compositions generally comprise surfactants, an acid, builders such as sequestrants and chelating agents, coupling agtnts, and various other adjuvants A The Surfactant System Generally, the compositions of the invention comprise surfactants to facilitate low foaming cleaning, and prevent hazing of the PET container Any number of surfactants may be used in accordance with the invention including nonionic surfactants, anionic surfactants, amphoteric surfactants, and mixtures thereof 15 Nonionic surfactants encompass a wide variety of polymeric compounds which include specifically, but not exclusively, ethoxylated alkylphenols, ethoxylated aliphatic alcohols, ethoxylated amines, ethoxylated ether amines, carboxyhc esters, carbovyhc amides, and polyoxyalkylene oxide block copolymers Preferably, nonionic surfactants are used in the invention such as those which 20 comprise ethylene oxide moieties, propylene oxide moieties, as well a mixtures thereof, and ethylene o\ide-propylene oxide moieties m either hetenc or block formation Additionally useful in the invention are nonionic surfactants which comprise alkyl ethylene oxide compounds, alkyl ethylene o\ide-propylene oxide compounds and alkyl ethylene oxide-butylene oxide compounds, as well as mixtures thereof 1 he ethylene 25 oxide propylene oxide moiety and ethylene oxidc-butylcne oxide moiety may be in either hetenc or block fonnation Also useful in the invention arc nomonic surfactants having any mixture of combination of ethylene oxide-propylene oxide moieties linked to an alkyl chain where the ethylene oxide and propylene oxide moieties may be in any randomized or ordered pattern and of any specific length Nonionic surfactants useful in 30 the invention may also comprise randomized sections of block and hetenc ethylene oxide propylene oxide, or ethylene oxide-butylene oxide Preferred nonionic surfactants include alkylphenols, alcohol ethoxylates and block copolymers of ethylene oxide and propylene oxide Examples of nonionic surfactants found useful in the invention include 35 (EO)/(PO) block copolymers having at least about 3 moles (EO) and at least about 15 moles (PO), aryl or aliphatic ethoxylates having at least about 3 moles (EO) which may or may not be capped with methyl, butyl, or benzyl moieties, aryl or aliphatic cthoxylate-propoxylate copolymers having at least about 2 moles of (EO) and from Printed from Mimosa about 4 moles of (PO) and whtch may also be capped with methyl, butyl or benzyl, and aryl or aliphatic ethoxylate-butoxylate copolymers 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 may comprise any branched or linear CR-C24 moiety The aryl 5 group may generally comprise aromatic structures such as benzyl An 11LB value of 4 to 13 may also be used to characterize surfactants useful m the invention Representative nonionics which are useful in the invention include EO/PO block copolymers available from Henkel KGaA, Pluronic L62 and L44 which arc EO/PO block copolymers available from BASF, Tergitol 15-S-3, TMN3, TMN10 which arc 10 ethoxylated alcohols available from Union Carbide, Surfonic L24-1 3 which is a linear alcohol ethoxylatc available from Texaco Chemical Co , nonyl phenol ethoxylates such as NPE 4 5, NPE 9, and Surfonic N120 available from Texaco Chemical Co , ethoxylated alkyl amines such as ethoxylated coco amine available from Sherex Chemical Co as Varonic K-215, an alkyl ethoxylated carboxyhc acid such as Ncodex 15 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 may oil out of the wash solution at a temperature of 59°C or less Preferably, the surfactant system comprises surfactants having a cloud point of about S°C to 60°C, preferably from about 20 10"C to 50°C, and more preferably of about 10 to 20°C so that in the alkaline wash solution, the surfactants will oil-out or film and deposit on the PET container surfacc providing protection against hazing One preferred line of surfactants includes Dehypon LT104 which is a C|2_18 fatty alcohol (EO)10 butyl capped and LS24 which is a Ct2 u iatty alcohol ((EO)2 (PO)4) both 25 available from Henkel Canada Ltd Anionic surfactants may also be used in the invention Typical commercially available anionic surfactants provide cither a carboxylatc, sulfonate, sulfate or phosphate group as the functional anion Wc have found that carboxylate based anionic surfactants such as alcohol ethoxylate carboxylates rcduce hazing of the container A 30 commercial source of this type of surfactant is Neodox 23-4™ available from Shell Chemical Co Amphoteric surfactants may also be used in the invention Such amphoteric surfactants include betaine surfactants, sulfobetaine surfactants, sarcosinate surfactants, amphoteric lmidazolinium derivatives and others Certain surfactants found useful in 35 hazing reduction include cocoyl and lauroyl sarcosine/sarcosinates such as ITamposyl C and L available from Hampshire Chcmical Co Printed from Mimosa 6 rCT/US96/18261 B Acid The composition of the invention may also comprise an acid source The acid functions to stabilize the surfactant system so that prior to mixing in the. wash solution, the concentrate is a true phase stable solution Once added to the alkaline wash solution 5 the acids are neutralized, become salt?, and provide heightened cleaning efficacy and retard the formation of scaling on washing machine components Generally, the acid may be any number of organic or inorganic acids Inorganic acids useful in the composition and the invention include phosphoric acid, polyphosphonc acid or acidic pyrophosphate salts, among others Orgamc acids 10 useful in the invention include mono and polycarboxylic acids such as acetic acid, hydroxyacctic acid, citric acid, gluconic acid, glucoheptanoic acid, lactic acid, succinic acid, malonic acid, glutanc acid, and mixtures thereof C Builders The composition of the invention may also comprise a builder Builders, l e , scquestrants and chelating agents, retard the precipitation of scale onto the side walls of the PET container and the bottle washing machine Builders also facilitate soil suspension, bind hardness ions and, in turn, enhance cleaning, during the washing process In accordance with one embodiment of the invention the first concentrate may 20 contain a first builder and the second concentrate may contain a second builder Builders uhich may be used in accordance with the invention include sequestrants such as phosphonates, phosphinatcs, acrylatcs and polyacrylatcs, and polycarboxylates among others Also useful as builders are malcatc polymers and copolymers of maleate and acrylate, salts such as polyaspartic and polyglutanc acid 25 salts, crythorbic acid, polyacrylamidopropyl sulfonate, and phospluno carboxyhc acid, among others Water soluble acrylic polymers which may be used include polyaciylic acid, polymcthacrylic acid, acrylic acid-methacrylic acid copolymers, hydrolyzed polyacrylamide, hydrolyzed methacrylamide, hydrolyzed acrylamide-methacrylamide 30 copolymers, and mixtures thereof Water soluble salts or partial salts of these polymers such as their respective alkaline metal (for example sodium or potassium) or ammonium salts can also be used Also useful as builders are phosphonic acids and phosphonic acid salts Such useful phosphonic acids include, mono, di, tn, tetra and, penta phosphonic acids which 35 can contain groups capablc of forming anions under alkaline conditions The phosphonic acid may also compnse a lower molccular weight phosphonopolycarboxylic acid such as one having about 2-4 carboxyhc moieties and Printed from Mimosa WO 98/22S66 PCTAJS96/18261 7 about 1 to 5 phosphonic acid groups Such acids includc 1 phosphono-l-methylsuccinic acid, phosphonosuccinic acid and 2-phosphonobutanc-l,2,4 tricarboxylic acid Preferred sequestrants include the Dequest® sequestrants available from Monsanto Co including Dequest 2006® which is amino tri(methylene phosphonic acid) 5 pentasodium salt, Dequest 2010® which is l-hydroxyethylidene-l,l-diphosphonic acid, Bayhibit AM® available from Mobay Chemical Co which is 2-phosphonobutane-1,2,4-tricarboxyhc acid, Dequest 2000® which is aminotri(methylene phosphonic acid), and Belsperse 161® from Ciba Gcigy which is a phosphino polycarboxylic aciu The builder present in either concentrate may also be a chelating agent Unlike a 10 sequestrant, the chelating agent tends to bind alkali 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 often indicated by inorganic salts which are left behind on the surface of the PET container The chelating agent removes these inorganic salts that are found 15 underneath the mold The number of bonds capable of being formed by a chelating agent upon a single hardness ion is reflected by labeling the chelating agent as bidentate (2), tridentate (3), tctradendate (4), etc Any number of chelating agents may be used in accordance with the invention Representative chelating agents include salts of ammo carboxyhc acids, 20 phosphonic acid salts, water soluble acrylic polymers, among others Suitable amino carboxyhc acid chelating agents include N-hydroxyethyliminodiacetic acid, nitnlotnacetic acid (NTA), ethyl enediammetetraacetic acid (EDTA), N-hydro\yethyl-ethylenediaminetnacctic acid (HEDTA), and diethylenetrianimepentaacetie acid (DTPA), as well as isosennc-N,N-diacetic acid, beta 25 alanine N,N-diacetic acid sodium glycolate, and tnpolyphosphate, among others In accordance with one useful aspect ot the invention the second builder present in the second concentrate comprises an amino carboxyhc acid chelating agent, preferably of ethylene diamine tetracetic acid or salts thereof D Cwiplerb The composition of the invention may also includc a coupling agent The coupling agent functions to stabilize the concentrate composition so that it is a true phase stable solution To this end, any number of organic coupling agents may be used including 35 sulfates, sulfonates, as well as monofunctional and polyftmctional alcohols Preferred coupling agents include sulfonate and sulfate compounds such as sodium xylene sulfonate, sodium cumene sulfonate, sodium toluene sulfonate, 2-cthylhcxyl sulfate, alkyl diphenyl oxide disulfonate where the alkyl group is either a branched C!2 or a Printed from Mimosa WO 98/22566 PCT/US96/18261 8 linear C|0, sodium alkyl naphthalene sulfonate, and sodium octane sulfonate and disulfonatc, and mixtures thereof Those coupling agents which have been found useful include linear alkyl alcohols such as, tor example, ethanol, isopropanol, and the like Also useful ure 5 polyfunctional hydroxy compounds such as alkylene glycols like hexylene glycol and propylene glycol, phosphate esters including Gaiac RP710 from Rlione-Poulence Chcmicals, and Triton 11-66 from Rohm & Haas Co E Adjuvants The compositions and methods of the invention may use any number of other adjuvants such as added nonionic surfactant defoamers such as those disclosed inUS Patent ]No 5,516,451 to Schmitt et al which is incorporated herein by reference Tracing compounds such as potassium iodide, colorants and dyes, fragrances, and preservatives, among other constituents are also useful in the invenuon The Method of Use The method of the invention provides heightened cleaning cfficacy of PET containers, removing soils, inorganic salts, and molds while retarding hazing of the containeis This result is obtauied by formulating a first acidic concentrate with a high 20 concentration of surfactant and a separate second concentrate having a high concentration of builder In accordance with one aspect of the invention the first and second concentrates may be incompatible if mixed separately from a wash solution Incompatibility in this context stems from different pH requirements of the two different eonccntrates The 25 first conccntratc 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 builder and is generally alkaline Combination of the two concentrates before dilution in the wash solution may result in phase separation of the surfactant system or the builder depending on pH 30 In use the two concentrates are combined in an alkaline wash system to provide heightened cleaning efficacy with good building cfficacy Illustrative concentration ranges for each of the two concentrates arc provided below Printed from Mimosa 9 TAULE1 Concentration (wt-%) More Concentrate 1 Useful Preferred Preferred Surfactant System 0 3-25 1-15 3-10 First Builder 0-20 -20 -20 Coupler 1-40 -20 -15 Acid (100% w/w) -30 -20 -15 Water qs qs qs Concentrate 2 Surfactant System 0-10 0 1-5 0 1-1 Second Builder 8-60 -45 -45 Water qs qs q s Use Solution Ippm^ Surfactant 6-500 -300 60-200 Builder 480-4000 1000-3000 2000-3000 Coupling Agent -800 60-400 100-300 In use this system is diluted into a wash solution comprising from about 0 1 wt-% to 0 8 wt-%, preferably from about 0 2 wt-% to 0 3 wt-% of the first conccntratc 5 and from about 0 2 to 1 2 wt-%, and preferably from about 0 4 wt-% to 0 8 wt-% of the sccond concentrate The ratio ot the first concentrate to the second concentrate in the alkaline wash solution generally ranges from about 0 1 0 5 to 0 1 10, and preferably from about 0102 to 01503 Generally the alkaline wash solution may have a total of from about 0 3 to 2 0 wt-% and preferably from about 0 5 to 1 2 wt-% of both 10 concentrate 1 and concentrate 2 In accordance with one preferred aspect of the invention, the wash solution comprises at least about 1000 ppm EDTA, at least about 5 ppm of a phosphonate compound, and at least about 100 ppm of a gluconate compound The washing of PET containers generally takes place over a number of steps 15 The PET containers are emptied and pre-rinsed, then soaked in the wash solution The wash solution generally has anywhere from 1 0 wt-% to 5 wt-% and preferably from 1 5 wt-% to 3 wt-% caustic (NaOH) Into this system is mixed Conccntrate 1 and Concentrate 2 into which the PET containers are applied Washing tends to take place over a time period which ranges from about 7 to 20 minutes The wash temperature is 20 about 59°C ± 1°C The containers then pass through a weak caustic stage where water is run into the tank to continue cleaning and begin rinsing by reducing the sodium Printed from Mimosa hydroxide concentration The caustic concentration may be maintained by a conductivity controller The containers then pass through al least three rinse stages u bich sequentially rinse the containers with warm water and cold water The final iinsing takes place with potable water after which time the containers arc turned upright, 5 inspected, and filled EXAMPLES The following working examples provide a nonlimiting illustration of the invention WORKING EXAMPLE 1 Hazing was studied using various compositions as detailed Provided below in Table 2 are examples which were tested along with other compositions in Table 3 TABLE 2 COMPOSITIONS EXAMPLE EXAMPLE 1A IB HjPO„ (75% w/w) 10 00 Gluconic acid (50% -w/w) 10 00 Dehypon LT-104 11 00 (Ci2 ii H24 n (EO)10 O0C4H9) Dehypon LS-24 5 00 (C,2 ,4 ^25-2y (EO)j (PO)4 OH) Triton BG-10 100 (alkyl polyglucosidc) Dequest 200030 (50% w/w) 6 00 6 00 (amino trimcthylenc phosphonic acid) Dequest 2010 (60% w/w) 2 00 (1 -hydroethyl idene-1, 1-diphosphonic acid) Bayhibit-AM® (50% w/w) 3 00 (2-phosphonobutane-l, 2,4-tricarboxylic acid) Fthylenc Diamine Tetra- 39 00 Acetic Acid, Tetrasodium salt (powder) Sodium Cumene Sulfonate 30 00 (40% w/w) VN-11 0 50 (olcyl alcohol dicthylcne glycol) Potassium Iodide 0 25 Printed from Mimosa 11 FCT/US96/18261 Chemical hazing was studied with PET strips (0 5" \ 2") which were cut out of amorphous (low crystallinity) PET sheeting The strips were immersed in about 200 mL of 2 8% caustic solutions containing various amounts of additives being tested The solutions were shaken at 100 rpm in a water bath with a temperature maintained 5 between 58-60°C for 24-72 hours The degree of hazing/corrosion was cvuluated visually and gravimetncally using water (hazing rating of 0) and a 2 8% caustic solution (hazing rating of 10) as references TABLE 3 EXAMPLE ACTIVE CONCENT RA HON HAZING 1A Table 2 0 05 wt-% 05 1A Table 2 0 2 wt-% 05 1A Table 2 0 6 wt-% 05 1A Table 2 2 0 wt-% 05 ID Table 2 0 05 wt-% IB Table 2 0 1 wt-% 75 IB Table 2 0 2 wt-% 5 IB Table 2 0 35 wt-% 1 5 1C Dehypon LT104 (Cu ]g H24_37 (EO)io OnC4Hg) ppm 0 ID Dehypon LS24 (C|2.)4 H25 29 (EO)2 (PO)4 OH) ppm 1 IE Tnton BG-10 (alkyl poly glucoside (70% w/w)) 300 ppm 8 IF Glucopon 600 (alkyl polyglucoside (C128 H276 O(C6III0Oj)mH)) 500 ppm 1G Sodium Cumene Sulfonate 300 ppm 9 Control 1 Water 0 wt-% 0 Control 2 Caustic 2 8 wt-% Hazing was measured against a scale of 0 for no hazing such as with water and 10 for 2 8% caustic Examples 1C and ID, as well as the senes of trials run on Example 1A proved these compositions to be very effective in preventing hazing whether used alone or in conjunction with sequestrants Printed from Mimosa 12 rCT/US96/18261 WORKING EXAMPLE 2 A second analysis of hazing was undertaken using the method of Example 1 with 100 ppm of cach activc (EXS 2A.-2W), and 2 8 wt-% ol NaOH in the wash water (except for tho control), the results are reported in 1 able 4 Tabic 4 EXAMPLE ACTIVE 2A 2F1 2C 2D 2E 2r 2G 2H 21 2J 2K 2L 2M 2N 2P 2Q (PO)24(EO)J(PO)l3 o(EO|5 5)](E0)15(I'0);i (PO)IJ(EO)1J[(EO)1J(PO)UJ](EO)„(PO)l3 (PO)J(LO)15[(P0)n0(EO153)](EO)13(PO)24 tfluronic L62 HO(EO)l)(PO>30(EO)gH Pluronic L44 IIO(EO)n(PO)2,(EO)llH Tergitol 15-S-3 (Cln3H23 3l(LO)3OH) Tergitol TMN 3 CI2HJ,(EO)JOH ItrgitolTMN 10 C12H25(EO),„OH Surfonic L24-1 3 (Cijm(EO)„OII) Plurafac LFH1 (C117(EO),(BO)|7OCH,) Dehypon LT104 (C,2I8HJ4 37 (EO)„ O„C4H9) (C6H3CH,MPO)B(EO)13[(EO)2,2/(PO)23J](EO)13(PO)ir (CH2C6H3) Cn uO(EO)10.12 CH2-C0HJ NPE 4 5 nonyl phenol (EO)43 NPE 9 5 nonyl phenol (CO),3 Surfonic N120 C9H1,C6H4(EO)12OH Neodox23-4 (C,j ,3(EO)4OCH2COOH) HAZING 0 0 1 0 0 Printed from Mimosa WO 98/22566 PCT/US96/1826I 13 2R VnromcK215 4 (cocoamine ethoxylale (EO)|3) 2S Hamposyl C 1 coco sarcosine (C,2 tBII2S ^CXOJNfCH^CHjCOOH) 2T Hamposyl I 4 lauroyl sarcosine 2U Hamposyl L 30 10 sodium loroyl sarcosinate 2V Silwct L77 5 (CH1)1SiOSi[(CHa)OSi(SH3)J]I(CH3)3(EO)lOCH3] 2W 2 8% NaOH (control) 10 Printed from Mimosa WO 98/27566 rCT/US96/18261 14 WORKING EXAMPLE 3 Soiled bottles from the field were cut into test panels (roughly 2" x 3") A washing test was done in 1000 mL solution with stirring (500 rpm) for 10 mm , followed by a 1 mm water rinse (8 psi nowle spray, top down) Methylene blue 5 staining was used to evaluate boil level both before and after the cleaning in accordance with the Industrial Code of Practice for Rcfillable Pet Bottles. Edition 1 (1993-1994 UNESDA/CESDA), page V-18 The above steps were repeated every 10 minutes for the 20 minute and 30 minute cleaning iterations The wash solution comprised 2 8 wt-% caustic, 0 6 wt-% Example 1B, and the varying amounts of Example 1A as shown in 10 Table 5A below Quadruplet data was used for statistical average The data was reported as total cleaned/total washed Table 5A 2 8% caustic 0 6% Example IB Cleaning Time Example 1A (wt-%) min min 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 Tabic In this example the wash solution comprised 2 8 wt-% caustic and 0 2 wt-% Example 1 A, with varying amounts of Example 1B as indicated below Data was reported as in Table 5A Cleaning Time Example IB (wt-%) lOrmn 20 mm 30 min 0 60 2/4 2/4 2/4 1 20 4/4 0 80 4/4 Printed from Mimosa

Claims (4)

WO 98/22566 PCT/US96/18261 15 Tnhlc 5C Different concentrations of Example 1A and IB were combined to test cleaning cfficacy Data was reported as in Tables 5A and 5B Cleaning Time Example 1A Example ID (wt-%) (wt-%) 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 07 2/4 2/4 3/4 0 20 08 2/4 2/4 3/4 0 20
1 0 4/4 0 30 04 2/4 2/4 2/4 0 40 04 2/4 2/4
2/4 10 Table 5D The cleaning efficacy of wash solutions having set concentrations of Example 1A and Example IB with vancd concentrations of caustic was then analyzed Example 1A was added at 0 2 wt-% to the wash solution and Example 113 was added at 0 8 wt-% to the wash solution The results are reported below in the same manner as Tables 5A -5C Caustic (wt-%) 1 5 20 26 10 min 24 2/4 3/4 Cleaning Time 20 mm 24 2/4 3/4 30 min
3/4
4/4 4/4 The above specification, examples and data provide a complete description of 15 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 claims hereinafter appended Printed trom Mimosa 16 WE CLAIM: 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 wash solution (a) said first concentrate comprising (i) from about 0 3 to 25 wt-% of a surfactant, and (n) from about 5 to 30 wt-% of an acid, (b) said second concentrate compnsmg (l) from about 8 to 60 wt-% of a builder, said method further comprising the step of contacting said container with said wash solution wherein the removal of soil is undertaken with minimal hazing of the container 2 A method for cleaning polyethylene terephthalate containers, said method comprising the steps of contacting the container with an alkaline wash solution having a temperature ranging from about 50°C to 60°C, said alkaline wash solution formulated from a first concentrate, a second concentrate, an alkalinity source, and a balance of water, (a) said first concentrate compnsmg a nonionic surfactant, a first builder, and acid in an amount effective to provide a phase stable solution, and (b) said second concentrate compnsmg a nonionic surfactant, and a second builder wherein said first and second concentrate are present m the wash solution in a total concentration ranging from about 0 3 wt-% to 2 0 wt-% , said first nonionic surfactant having a cloud point ranging from about 25°C to 60°C 3 The method of claim 1, wherein said first concentrate further comprises a first builder and said second concentrate compnses a second builder 4 The method of claim 1, wherein said second concentrate further comprises a surfactant 5 The method of claim 1 or 2, wherein the concentration of the first concentrate added to said wash solution ranges from about 0 1 vvt-% to 0,8 wt-% of the wash solution 6 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 7 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 10 8 The method of claim 1, wherein said wash solution comprises from about 0 3 wt-% to 2 0 wt-% total of said first and second concentrate 9 The method of claim 1 or 2, wherein the alkaline wash solution comprises from about 1 wt-% to 5 wt-% of a source of alkalinity 10 The method of claim 9, wherein said alkalinity source comprises about 1 5 wt-% to 3 wt-% caustic 11 The method of claim 1 or 2, wherein said first concentrate further comprises a coupler 12 The method of claim 11, wherein said coupler is selected from the group consisting of sodium xylene sulfonate, 2-ethyl hexyl sulfate, sodium cumene sulfonate, sodium toluene sulfonate, sodium alkyl naphthalene sulfonate, sodium octane sulfonate, a branched alkyl diphenyl oxide disulfonate, a linear alkyl diphenyl oxide disulfonate, and mixtures thereof 13 The method of claim 11, wheiem said coupler comprises a polyfunctional hydroxy compound 14 The method of claim 11, wherein said coupler comprises a phosphate ester 15 The method of claim 1, wherein said wash solution has a temperature of from about 50 to 70°C 18 16 The method of claim 1 or 2, wherein said wash solution has a temperature of less than about 60°C 17 The method of claim 1, wherein said surfactant is selected from the group consisting of a nonionic surfactant, an anionic suifactant, an amphoteric surfactant and mixtures thereof 1S The method of claim 1, wherein said surfactant comprises a nonionic surfactant 19 The method of claim 18, wherein said nonionic surfactant is selected trom the group consisting of an ethylene oxide - propylene oxide block copolymer, an alkyl ethoxylate, an alkyl ethoxylate - propoxylate, an alkyl ethoxylate -butoxylate, and mixtures thereof 20 The method of claim 3, wherein said first builder is selected from the group consisting of phosphonates, phosphmates, acrylates, polycarboxylates, and mixtures thereof 21 The method of claim 3, wherein said second builder comprises a chelating agent of ethylene diamine tetraacetic 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 builder comprises an alkylene polyamme polyacetic acid salt 24 The method of claim 1, wherein said acid is selected from the group consisting of an organic acid, an inorganic acid, and mixtures thereof 25 The method of claim 24, wherein said acid comprises a 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 of mold 28 A wash solution resulting from the method of claim 1 or 2, said wash solution comprising from about 6 to 500 ppm surfactant and from about 480 to 4000 ppm builder and further comprising from about 20 to 800 ppm coupling agent 29 The method of claim 2, wherein (a) said first concentrate comprises (i) from about 1 to 15 wt-% of said first nonionic surfactant, (n) from about 5 to 20 wt-% of said first builder, and (m)from about 10 to 20 wt-% of said acid, and (b) said second concentrate comprises (I) from about 0 1 to 5 wt-% of said second nonionic surfactant, and (II) from about 15 to 45 wt-% of said second builder 30 A wash solution resulting from the method of claim 2 or 3, said wash solution compnsmg from about 6 to 500 ppm surfactant, at least about 5 ppm of said first builder, said first builder comprising a phosphonate compound, and at least about 1000 ppm of said second builder, said second builder compnsmg ethylenediamine tetra acetic acid or a salt thereof 31 An alkaline wash solution for cleaning polyethylene terephthalate bottles, said wash solution compnsmg a mixture of (a) from about 1 to 5 wt-% of a source of alkalinity, (b) from about 480 to 4000 ppm of a builder, (c) from about 6 to 500 ppm of a surfactant, and (d) from about 20 to 800 ppm of a coupler said coupler selected from the group consisting of a sulfonate compound, a disulfonate compound, a sulfate compound, and mixtures thereof 32 The wash solution of claim 31, wherein the alkaline wash solution comprises from about 1 5 wt-% to 3 wt-% of a source of alkalinity 33 The wash solution of claim 31, wherein said coupler is selected from the group consisting of sodium xylene sulfonate, 2-ethylhexyl sulfate, sodium 20 cumene sulfonate, sodium toluene sulfonate, sodium alkyl naphthalene sulfonate, sodium octane sulfonate, a branched alkyl diphenyl oxide disulfonate, a linear alkyl diphenyl oxide disulfonate, and mixtures thereof 34 The wash solution of claim 31, wherein said surfactant comprises a nonionic surfactant 35 The wash solution of claim 34 wherein said nonionic surfactant is selected from the group consisting of an ethylene oxide - propylene oxide block copolymer, an alkyl ethoxylate, an alkyl ethoxylate - propoxylate, an alkyl ethoxylate - butoxylate, and mixtures thereof 36 The wash solution of claim 31, wherein said builder is selected from the group consisting of phosphonates, phosphinates, acrylates, polycarboxylates, and mixtures thereof 37 The wash solution of claim 31, wherein said builder comprises ethylene diamine tetraacetic acid or a salt thereof 38 The wash solution of claim 31, compnsmg at least about 1000 ppm of ethylenediamme tetraacetic acid or a salt thereof and at least about 5 ppm of a phosphonate compound and further compnsmg at least about 100 ppm of a gluconate compound 39 The method of claim 1, wherein (a) said first concentrate further compnses a first builder, said first concentrate comprising (I) from about 1 to 15 wt-% of said surfactant, wherein said surfactant is nonionic, (II) from about 10 to 20 wt-% of said acid, (III) from about 5 to 20 wt-% of said first builder, and (b) said second concentrate further compnses a second surfactant, said second concentrate compnsmg (l) from about 0 1 to 5 wt-% of said second surfactant, wherein said second surfactant is nonionic, and (u) from about 15 to 45 wt-% of said second builder 21 40 A method for cleaning a polyethylene terephthalate containei, substantially as herein described with reference to any one of the Examples, excluding comparative examples 41 A method of any one of claims 1 -27, 29 or 39, substantially as herem described 42 An alkaline wash solution for cleaning polyethylene terephthalate bottles, substantially as herein described with reference to any one of the Examples, excluding comparative examples 43 A wash solution of any one of claims 28 or 30-38, substantially as herein described END OF CLAIMS
NZ335914A 1996-11-15 1996-11-15 Cleaning method for polyethylene terephthalate containers using an alkaline wash solution NZ335914A (en)

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