WATER CLARIFYING COMPOSITIONS
FIELD OF THE INVENTION
The present invention relates generally to water clarifying compositions, and more particularly to water clarifying compositions comprising combinations of two or more polymeric or non-polymeric non-oxidizing water treatment compositions.
BACKGROUND OF THE INVENTION
The clarity of recreational waters is an important aspect of overall water quality. This is especially true in residential and commercial swimming pool applications where the clarity of the water indicates to the swimmer that the water is clean and pure.
Unfortunately, water can become cloudy as microorganisms (from the environment and swimmers), airborne particles and swimmer wastes accumulate, overwhelming the system's filtering capacity. When that happens, oxidizers such as chlorine, bromine, hydrogen peroxide and potassium peroxymonopersulfate are routinely used to achieve and maintain clean water. These oxidizers are typically added as solid, slow-release formulations, powders or liquids that achieve a desired level of oxidizer concentration.
There are, however, well-known drawbacks to using conventional oxidizers to clarify swimming pool water. For example, chlorine and bromine levels must be maintained at levels of 1-3 ppm and 4-6 ppm, respectively. Moreover, periodic superchlorination or superbromination is usually required to assure microbiological control and adequate
water quality. Hydrogen peroxide and potassium peroxymonopersulfate must be used in much higher concentrations because they are weaker oxidizers than the halogens (chlorine and bromine). Further, any oxidizer will cause bather irritation if the levels are too high.
Nonoxidizing antimicrobials such as polyquaternary ammonium compounds and PHMB are also known to be effective for controlling biofouling in various circulating water systems. For example, polyquats such as Q6/6 and PDED are important microbiocides and are widely used in water treatment.
Nonoxidizing antimicrobials are not, however, known to be effective clarifiers. Although PDED and PHMB have demonstrated some clarification properties under certain conditions, they are used primarily as antimicrobials in water treatment applications. The clarification that has been observed with these compositions has been attributed to the death of biofouling microbes and does not involve water that was repeatedly challenged by swimmer wastes. it is also known that nonoxidizing biocides may sometimes be used in combination with other nonoxidizers to more effectively deal with the great diversity of microbial populations. From the perspective of antimicrobial performance, using combinations of biocides in tandem decreases the ability of microorganisms to adapt, since microbial adaptation to individual biocides is not uncommon.
Another important reason for using two antimicrobials simultaneously is to take advantage of synergistic effects. That is, some biocides have been shown to be more effective when ' ombined with other antimicrobials. Even if there are no biocidally synergistic interactions, one compound may act as a non lethal adjuvant or potentiator for another. Although it would be desirable to apply products such as these in a single formulation, this may not be possible due to inherent blending incompatibilities. That is, the compounds of interest may not be miscible.
A need therefore exists for shelf-stable, preblended water clarifying compositions, and for compositions that increase the effective life of swimming pool oxidizers. A need also exists for water treatment compositions that are preblended combinations of two or more immiscible polyquaternary a onium compounds. The present invention addresses those needs.
SUMMARY OF THE INVENTION
Briefly describing one aspect of the present invention, two or more polymeric or non-polymeric non-oxidizing agents are blended with hydrogen peroxide to make shelf-stable, water clarifying concentrates. In some preferred embodiments, non-oxidizing polymers such as polyquaternary ammonium compounds such as poly[hexamethylenedimethyl ammonium] chloride (Q6/6), Q12/6 (a homolog of Q6/6), Q4/6 (another homolog of Q6/6) , PDED and IPCP are combined to make preblended water treatment concentrates.
Non-polymeric, non-oxidizing compositions such as ADBAC, DDAC, DIDAC, DDC and DGH may also be used in the preblended concentrates.
In another aspect of the invention two or more immiscible polymeric compounds are combined in one preblended composition by using concentrated hydrogen peroxide as a formulating aid.
One advantage of the present invention is the provision of improved water clarifying compositions. Another advantage of the present invention is the provision of compositions that increase the effective life of swimming pool oxidizers.
A third advantage of the present invention is the ability to combine two or more previously incornpatable polymeric compounds into one preblended water treatment composition.
Further aspects and advantages of the present invention will be apparent from the following description.
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a tank apparatus as used in the examples
FIG. 2 is a graph showing the effect of polymer on .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
For the purpose of promoting an understanding of the principles of the invention, reference will now be made to preferred embodiments and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, such alterations and further modifications in the illustrated device, and such further applications of the principles of the invention as illustrated therein being contemplated as would normally occur to one skilled in the art to which the invention relates.
As previously described, one aspect of the present invention deals with the non-biocidal properties of cationic polymers in aqueous systems, and specifically with their ability to enhance water quality. In particular, the present invention relates to water enhancement including water clarification and/or reducing the amount of oxidizer demand present in aqueous systems. These phenomena have previously not been observed with monomeric cations (e.g., monomeric quaternary ammonium salts) .
In addition, one aspect of the present invention provides a method of formulating preblended liquid concentrates for treating water with a combination of polymeric or non-polymeric compounds. Surprisingly, combinations of water treatment agents that are immiscible when blended alone may be preblended to make effective water treatment concentrates when formulated with concentrated hydrogen peroxide.
I " rther describing one aspect of the present invention, there are provided synergistic combinations of cationic polymers (such as Q6/6, PHMB and PDED) and oxidizers (such as H_0_ and chlorine) for use in clarifying swimming pool waters. It can be seen from the following data that the compositions of the present invention work far better
for clarifying water than either polyquats or oxidizers acting alone.
The polymeric cations of one aspect of the present invention include polyquaternary ammonium compounds (polyquats) such as 1, 6-hexanediamine-N,N,N' ,N' -tetramethyl polymer with 1, 6-dichlorohexane (Q6/6, also identified as poly[hexamethylenedimethyl ammonium] chloride) and two of its homologs (Q12/6 and Q4/6) . These compounds are known to the art and may be prepared as described, for example, in U.S. Patent No. 5,142,002 to Metzner. In addition, the polyquaternary ammonium compound poly[oxyethylene- (dimethylimino) ethylene-(dimethyli ino) ethylene dichloride] (PDED) or polycations such as pol (iminoimidocarbonyl- iminoimidocarbonyliminohexamethylene) chloride (also called polyhexamethylene biguanide or PHMB) may be used.
For the purposes of this disclosure, the term "oxidizer" is defined consistent with the use of that term by persons of ordinary skill in the art of swimming pool water treatment. Oxidizers useful in the synergistic compositions of the present invention include chlorine, bromine, H_0~, and other oxygen-releasing oxidizers.
In another aspect of the invention concentrated hydrogen peroxide is used as a formulating agent for concentrated, miscible or immiscible mixtures of polymeric or non-polymeric compounds such as polymeric quaternary ammonium compounds (polyquats), monomeric, dimeric or oligomeric quaternary ammonium compounds (quats), etc. More particularly, compounds such as poly(hexamethylammonium) chloride (Q6/6), isomers of Q6/6 (particularly, Q12/6 and Q4/6), poly [oxyethylene (dimethylimino) ethylene-(dimethylimino) ethylene] dichloride (PDED), dodecamethylene-dimethylimino chloride (Q6/12), 1,3-diazo-2,4-cyclopentadiene with l-chloro-2,3- epoxypropane (IPCP), dodecylguanidine hydrochloride (DGH),
diisodecyldi ethyl ammonium chloride (DDC), alkyldimethylammonium chloride (ADBAC) ,
N-decyl-N-isononyl-N,N-dimethylammonium chloride (DIDAC) and didecyldimethyl ammonium chloride (DDAC) are examples of compounds that are preferably formulated with hydrogen peroxide as disclosed and claimed in this aspect of the present invention.
Reference will now be made to specific examples using the processes described above. It is to be understood that the examples are provided to more completely describe preferred embodiments, and that no limitation to the scope of the invention is intended thereby.
EXAMPLES
Experimental Setup. Microbes such as Pseudomonas aeruginosa, Escherichia CPU/ and Staphvlococcus aureus are some of the major bacteria which can be recovered from recreational waters after swimmer use. Mixtures of these bacteria (ca. 10 - 10 organisms) were added to 10 gallon tanks containing balanced pool water (200 ppm calcium carbonate, 120 ppm calcium sulfate, pH 7.4) . In addition, 10 ml of a synthetic insult was added to each aquarium at the time of inoculation.
The synthetic insult used in the following examples was composed of: Components g/L
NaCl 40.0
K2SO 4.0
Na2S04 0.8
MgSθ 8.0 CaCl2 0.56
Dextrose 1.2
Lactid Acid 8.0
Pyruvic Acid 0.4
Urea 29.2 Creatinine 1.6
An attached pump and filter assured adequate mixing.
The filter contained a 4 x 7 inch section from a standard pool cartridge filter inside a porous housing. See Fig. 1. Three tanks were used for each experiment.
EXAMPLE 1
Experiment 1 was performed to determine the water clarification potential of low doses of conventional oxidizers. Four ten-gallon tanks were filled with balanced pool water. Tanks 1 and 2 contained no oxidizer. Tanks 3 and 4 contained H_02 and chlorine, respectively. Oxidizer was added daily to achieve a desired oxidizer concentration.
Pieces of compressed oxidizer were placed into the water intake tube of the pump. Dissolved oxidizer traveled through the pump and filter assembly and then into the bulk water. Skimmer fed oxidizer is applied this way in actual pools. After achieving the desired residual oxidizer level, bacteria were added to tanks 2, 3 and 4. Tank 1 was the only tank which received neither bacteria nor oxidizer.
Table 1 shows the results of experiment 1. It can be seen from Table 1 that low levels of chlorine or H_0_ had no demonstrable effect on water clarity.
Table 1. Clarifying Effect Of Oxidizer Only.
EXAMPLES 2 -4
Experiments 2-4 were performed to demonstrate the effects of polymeric cations (such as polyquaternary ammonium compounds) and chlorine on water quality. Two ten-gallon tanks were dosed with about 5 ppm of either Q6/6, Q12/6, Q4/6 or PDED. One of these tanks and the third tank was treated with low levels of chlorine. Pieces of compressed chlorine (trichloroisocyanurate) were placed into the water intake tube of the pump. Dissolved chlorine traveled through the pump and filter and then into the bulk water, as typically applied in swimming pools.
Chlorine levels were measured by titration with 0.1 N sodium thiosulfate. After achieving a chlorine residual of ca. 0.5 ppm (usually no higher than 1 ppm) or less, bacteria were added.
Tables 2-4 show the synergistic effect that chlorine and polyquats have on water quality. In each of the tables, tank #1 was dosed with compressed trichloroisocyanurate for successive days, tank #2 was dosed with ca. 5 ppm of cationic polymer and tank #3 contained a mixture of chlorine and cationic polymer. Bacteria were added each day. The amount of bacteria added was sufficient to give the water a cloudy appearance.
Water turbidity (NTU) was initially measured after about 3 hours, and was measured daily thereafter. After the first
inoculation (Day 1), tank #1 required twice as long as tank #3 to reach a comparable chlorine residual.
Water turbidity was high after the first inoculation and increased with subsequent inoculations (tank #1) . Tanks containing only polyquats were substantially clearer (tank #2). Tank #3 generally had the lowest turbidities. In actual pools, a turbidity reading of greater than 0.3 NTU is considered hazy.
Spot microbiological testing revealed no direct correlation between bacterial density and water clarity. In some cases, tanks with high turbidities showed low or no bacterial counts. By contrast, some of the least turbid tanks had the highest bacterial counts. Therefore, clarification can be seen to correlate specifically to the reduction in turbidity, and not necessarily to a reduction in the microbial population.
In all cases, the amounts of oxidizers used were too low to give adequate clarification after the first day. However, some combinations of oxidizers and polymers showed a synergistic effect upon clarification. All of the polymers enhanced water quality by decreasing the amount of oxidizer consumed by the system's demand. In this way, the overall effectiveness of the cationic polymers increased the effectiveness of the oxidizers by allowing them to remain active for longer periods of time.
Table 2. Enhanced Chlorine:Q6/6 Clarifier.
Table 3. Enhanced Chlorine: 12/6 Clarifier.
Tahle 4. Enhanced Chlorine: PDED Clarifier.
EXAMPLES 5-9
Tables 5-8 show the effect of polycations upon hydrogen peroxide stability. Table 9 shows the effect of a cationic monomer, alkyldimethylammonium chloride (ADBAC) , upon peroxide and water clarity.
In all cases, polymeric cations decreased the amount of oxidizer demand, extending the half life of the H_0_. However, Table 9 indicates that the beneficial effects that cations have on water quality may be limited to polymers. The monomeric cation did not extend the H_02 half life, and had little if any effect upon water clarity.
Table 8 demonstrates that the cationic polymer PHMB also showed clarification synergy with hydrogen peroxide. This proves that the synergistic effect between oxidizers and cationic polymers is not a property unique to polyquaternary ammonium compounds such as Q6/6 and PDED. PHMB was not tested in the presence of chlorine because it is not compatible with oxidizing halogens.
Table 5. Enhanced Peroxide:Q6/6 Clarifier.
Table 6. Enhanced Peroxide: PDED Clarifier.
Table 7. Enhanced Peroxide :Q 12/ 6 Clarifier.
Table 8. Enhanced Peroxide: PHMB Clarifier ,
Table 9. Effect of ADBAC Quat on Water Clarity.
EXAMPLE 10
In another experiment, various cations (polymers and monomers) and H202 were tested as clarifiers in cloudy water containing PHMB. Nine aquariums were dosed with 5 ppm of PHMB and inoculated on successive days with suspensions of P. aerugjnpsa, £• coli. £. aureus and synthetic sweat until the water remained cloudy for at least 18 hr. Cloudy water is a recalcitrant problem associated with PHMB sanitized pools.
The list of potential clarifiers included polycations (Q6/6, Q12/6, Q4/6, PDED and PHMB), the monomeric cation diisodecyl dimethyl ammonium chloride (DDAC) and H O . Each quat was dosed at 10 ppm along with 10 ppm H_0_ . The results are recorded in Table 10.
The data in Table 10 indicate that mixtures of cationic polymers with low levels of H O can act as clarifiers in cloudy PHMB systems. By contrast, monomeric cations were unable to act as clarifiers under any circumstances (Tables 9 and 10). H202 alone demonstrated clarification because its dose was tripled to roughly 30 ppm.
Table 10. Ability of Compounds to Clarify Cloudy Water.
A triple dose of H202 was used (30 ppm) , in lieu of the usual 10 ppm.
EXAMPLE 11
The ability of polyquats to extend the life of oxidizers in non halogen systems was demonstrated by an outdoor experiment using actual swimmers. Two above-ground pools (5,000 gallons each) were treated with 10 ppm PHMB, 2 ppm ADBAC quat and 27 ppm of H202. Five parts per million of Q6/6 was added to one of the pools. Swimmers spent an average of 16 total hours (4 swimmers/pool, 2 hours each) per week in one pool. Hydrogen peroxide levels were monitored daily and are recorded in FIG. 2.
FIG. 2 shows that the pool with 5 ppm Q6/6 maintained consistently higher peroxide levels than the pool without any polyquat. Moreover, the pool without polyquat required greater and more frequent re-applications of H«0„ than the pool with Q6/6. In spite of these larger peroxide additions, the pool without the additional cationic polymer was unable to achieve the H_0_ levels found in the pool containing the polyquat (Fig. 2). This field research corroborates the extensive laboratory studies summarized in Tables 1-8.
Although the pool with the polyquat maintained higher H-0? levels, the laboratory data indicate that a pool utilizing a monomeric cation and peroxide would have had ssuubbssttaannttiiaallllyy lloower H_0_ levels than the PHMB pool without polyquat
EXAMPLE 12
Determination of miscibility of polyquaternary amonium compounds .
In order to determine whether certain combinations of non-oxidizing compounds which may demonstrate biocidal or clarification synergy when used simultaneously could be blended together as concentrated products, a variety of useful polymeric water treatment agents were combined to determine their relative miscibilities . The Table below shows blends of several polyπ.'ric and non-polymeric compounds that are or might be commercially valuable as biocides, clarifiers or stabilizers in water treatment, hard surface sanitizers or consumer products. "M" and "I" denote miscible and immiscible, respectively.
TABLE: BLENDS OF POLYMERIC AND NON-POLYMERIC COMPOUNDS.
06/6 06/12 PDED IPCP ADBAC DDAC DIDAC DDC DGH
Q6/6 M I M M I I I I I
Q6/12 I M I M M I I I M
PDED M I M M I I I I I
IPCP M M M M I I I I I
ADBAC I M I I M M M M M
DDAC I I I I M M M M M
DIDAC I I I I M M M M M
DDC I I I I M M M M M
DGH I M I I M M M M M
Solutions of concentrated hydrogen peroxide (0.1-50%) are blended with compounds that may or may not be readily miscible. These non-oxidizing blends hold commercial value for treating industrial or recreational regulated waters, hard surface sanitization or for household consumer use. The concentrated solutions are preferably applied as a single product in waters or on hard surfaces. The
combinations of non-oxidizing compounds are preferably added to the peroxide in concentrations ranging from 0.1-10%.
EXAMPLE 13
Blends of immiscible polyquaternary amonium compounds.
The combination of Q6/6 and Q6/12 was determined to be immiscible when blended as concentrates. Concentrated (35%) hydrogen peroxide was used as a disolution agent to prepare an aqueous Q6/6:Q6/12 :hydrogen peroxide blend with a final formulation of about 5% Q6/6, about 5% Q6/12, and about 25% hydrogen peroxide. No phase separation occured, and the concentrated water treatment product was observed to be shelf-stable for a period of at least about 60 days when stored at room temperature.
EXAMPLE 14 Blends of immiscible polymeric water treatment agents.
The combination of PDED and Q6/12 was determined to be immiscible when blended as concentrates. Concentrated (35%) hydrogen peroxide was used as a disolution agent to prepare an aqueous PDED:Q6/12:hydrogen peroxide blend with a final formulation of about 2% PDED, about 3% Q6/12, and about 30% hydrogen peroxide. No phase separation occured, and the concentrated water treatment product was observed to be shelf-stable for a period of at least about 60 days when stored at room temperature.
EXAMPLE 15
Blends of immiscible polymeric and non-polymeric water treatment compositions.
The combination of Q6/6, PDED and DIDAC was determined to be immiscible when blended as concentrates. Concentrated (35%) hydrogen peroxide was used as a disolution agent to prepare an aqueous Q6/6 :PDED:DIDAC:hydrogen peroxide blend with a final formulation of about 5% Q6/6, about 10% PDED, about 2% DIDAC and about 25% hydrogen peroxide. No phase separation occured, and the concentrated product was observed to be shelf-stable for a period of at least about 60 days when stored at room temperature.
It can be seen from the above that hydrogen peroxide is an effective formulating agent for compounds such as those listed in the Table above. This list is not exhaustive however, and merely identifies representative examples of compounds which one skilled in the art might use in compositions formulated with hydrogen peroxide according to the present invention.
EXAMPLE 16
Shelf-stable, preblended combinations of non-oxidizing cationic polymers and hydrogen peroxide.
Shelf-stable, preblended concentrates of Q6/6 and hydrogen peroxide are prepared by combining 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 95% portions of
concentrated hydrogen peroxide with 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, and 5% portions, respectively, of Q6/6 to make a liquid concentrate. The concentrates were observed to be shelf-stable for at least about 60 days when stored at room temperature.
EXAMPLE 17
Shelf-stable, preblended combinations of non-oxidizing cationic polymers and hydrogen peroxide.
Shelf-stable, preblended concentrates of Q12/6 and hydrogen peroxide are prepared by combining 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 95% portions of concentrated hydrogen peroxide with 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, and 5% portions, respectively, of Q12/6 to make a liquid concentrate. The concentrates were observed to be shelf-stable for at least about 60 days when stored at room temperature.
EXAMPLE 18
Shelf-stable, preblended combinations of non-oxidizing cationic polymers and hydrogen peroxide.
Shelf-stable, preblended concentrates of Q4/6 and hydrogen peroxide are prepared by combining 5%, 10%, 20%, 30%, '.0%, 50%, 60%, 70%, 80%, 90%, and 95% portions of concentrated hydrogen peroxide with 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, and 5% portions, respectively, of Q4/6 to make a liquid concentrate. The concentrates were observed to be shelf-stable for at least about 60 days when stored at room temperature.
EXAMPLE 19
Shelf-stable, preblended combinations of non-oxidizing cationic polymers and hydrogen peroxide.
Shelf-stable, preblended concentrates of PDED and hydrogen peroxide are prepared by combining 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 95% portions of concentrated hydrogen peroxide with 95%, 90%, 80%, 70%, 60%, 50%, 40%, 30%, 20%, 10%, and 5% portions, respectively, of PDED to make a liquid concentrate. The concentrates were observed to be shelf-stable for at least about 60 days when stored at room temperature.
While the invention has been illustrated and described in detail in the foregoing description, the same is to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiment has been shown and described and that all changes and modifications that come within the spirit of the invention are desired to be protected.