Background of the Invention

1. Field of the Invention

The invention relates to a drain cleaner in which a critical ratio and amount of at least one nonionic surfactant and, optionally, one or more cosurfactants, results in vastly improved grease removal in drains.

2. Brief Statement of the Related Art

There are many approaches to removal or dissolution of grease buildups in kitchen sink and lavatory drainpipes. As is well known, the grease buildups themselves plug, clog or slow the drains, thus preventing or hindering the routine removal of waste water in sinks and lavatories. In one commonly attempted solution, caustic chemicals, such as crystallized lye, are introduced into the standing water. While fat hydrolysis is intended by such an effort, in fact, the actual result is that an exothermic reaction caused by the reaction of the lye and water merely heats the standing water to boiling, usually, without much action on the grease clog.

Another approach is to use a biological drain opener, in which a combination of fat-digesting microorganisms which colonizes and digests the clog over time. The microorganisms typically include a mixture of bacteria which uses hydrolase enzymes to digest the clog, such as proteases and Upases. An example of this type of cleaner is described in EP 0 569 140 (Sybron Chemical Co.).

However, heretofore, no one had employed a drain cleaner in which a critical ratio and amount of at least one nonionic surfactant and, optionally, a cosurfactant resulted in vastly improved grease removal in drains.

Summary of the Invention and Objects The mvention provides an unproved dram cleaner comprising a fat-solubilizing amount of at least one nonionic surfactant and, optionally, one or more cosurfactants, providing thereby at least about 0 08g of active surfactant to a grease clog

In other embodiments, various additives can be added, including, but not limited to, solvents, enzymes, microorgamsms, fragrances, preservatives and other adjuncts known to those skilled in the art

It is therefore an object of this invention to improve grease clog removal from the drain pipes and traps of sinks and lavatories

It is another object of this invention to use a critical amount of surfactants to effect enhanced grease clog removal performance

It is a further object of this invention to improve grease clog removal of enzyme or microorganism-containing drain buildup removal formulations

Detailed Description of the Invention

The invention is an improved drain cleaner comprising a fat-solubilizing amount of at least one nonionic surfactant and, optionally, one or more cosurfactants. thereby providing at least about 0 08g of actives to a grease clog

Additional adjuncts such as solvents, enzymes, microorganisms, fragrances, dyes, preservatives and the like can be included to provide desirable attributes of such adjuncts

In the application, effective amounts are generally those amounts listed as the ranges or levels of ingredients in the descriptions which follow hereto Unless otherwise stated, amounts listed in percentage ("%'s") are in weight percent of the composition, unless otherwise noted

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1. Nonionic Surfactants

The nonionic surfactant is generally chosen from the C ₁₀ ., ₅ linear alkyl ethoxylates. with an ethylene oxide content of about 5 to 9 moles of ethylene oxide per mole of alcohol ("EO").

Representative surfactants include the Alfonic surfactants, sold by Conoco, such as Alfonic 1412-60, a C, ₂ . ₁₄ ethoxylated alcohol with 7 moles of EO; Neodol surfactants, sold by Shell Chemical Company, such as Neodol 25-7, a C, _2.IS ethoxylated alcohol with 7 moles of EO, Neodol 45-7, a C, ₄ . ₁₅ ethoxylated alcohol with 7 moles of EO; Surfonic surfactants, also sold by Huntsman Chemical Company, such as Surfonic L24-7, a C ₁₂ .ι ₄ ethoxylated alcohol with 7 moles of

EO; and Tergitol surfactants, sold by Union Carbide, such as Ter itol 25-L-7, a C, _: . ₁₅ ethoxylated alcohol with 7 moles of EO. These nonionic surfactants are all liquids, with generally 100% active level and excellent surfactancy, having hydrophile-lipophile balances ("HLB") in the area of about 8-15. It is these particular surfactants which are especially important to the performance of the inventive drain cleaner.

2. Cosurfactants

At least one cosurfactant is also optionally present in the invention and is typically either. ( 1 ) a linear alcohol ethoxylate with a lower EO content than the previously mentioned surfactant; (2) a secondary alcohol ethoxylate; (3) a branched chain ethoxylated alcohol, such as a tridecyl ether ethoxylate; (4) an alkyl ether ethoxylate; (5) an ethoxylated trimethyl nonanol derivative; and (6) an anionic alkyl phosphate ester. Mixtures of the foregoing are also included in this invention.

The linear alcohol ethoxylate with a lower EO content with typically a lower EO content than the surfactant would include: Alfonic 1412-40, a C, ₂ . ₁₄ ethoxylated alcohol with 3 moles of EO; Neodol 25-3, a C, _: . ₁₅ ethoxylated alcohol with 3 moles of EO, Neodol 91-2.5, a C ₉ . _π ethoxylated alcohol with 2.5 moles of EO; Surfonic L24-3. a C _{ι : i4} ethoxylated alcohol with 3 moles of EO; and

Tergitol 25-L-3. a C _{! :} .u ethoxylated alcohol with 3 moles of EO. In contrast to the surfactant, this cosurfactant will generally act more as a wetting agent and will be more oil soluble than water soluble.

The secondary ethoxylated alcohols include Tergitol 15-S-3, a C _{1 5} secondary ethoxylated alcohol, with 3 moles of EO, from Union Carbide.

The branched surfactants, especially preferred of which are tridecyl ethers, include Trycol TDA-3, a tridecyl ether with 3 moles of EO, from Henkel KGaA (formerly, Emery), and Macol TD 3, a tridecyl ether with 3 moles of EO, from PPG Industries.

The alkyl ether ethoxylates include C _β ., _g alcohol alkoxycarboxylates, such as the Sandopan esters, e.g., Sandopan DTC, from Sandoz Chemicals.

The phosphate esters include 2-ethylhexyl, octyl, and decyl phosphates, sold by a number of manufacturers (See, also, Kirk-Othmer, Encyclopedia of Chemical Technology, 3rd Ed., p. 361, (1983), incorporated herein by reference).

The amount of surfactant and cosurfactant to be included in the novel drain opener formulations herein should be present in the formulation at a level above about 1.5%, but below about 6%, with the greatest effect achieved between 2.5% to 5%. It has surprisingly been found that the level of surfactant and cosurfactant ("Total Surfactant level") is critical. First, while a low level of Total Surfactant (e.g., 1%) is ineffective to remove a fatty clog, it has also been found that once the critical threshold amount to dissolve/disperse the fatty clog has been achieved, there is a peak effect which is not further improved once the 6% level has been exceeded. Further, there is a relationship between the surfactant and the cosurfactant, when present, in which the ratio of surfactant to cosurfactant must be at least 1 .2. and is most preferably greater than 1 : 1.

Because of the limited surface area of a clog which is available to be acted on by the surfactant, or surfactant cosurfactant mixture, it has been discovered that a critical amount of the surfactant, or surfactant/cosurfactant mixture effectively removes/disperses grease. And, beyond this critical amount, little or no further effect is seen. It is speculated that because there is such a limited surface area in the drain for the surfactant to attack, that this results in the need for the critical amount. This is thus dramatically unlike hard surface cleaning, where there is a linear correlation between the amount of surfactant used and the amount of soil removed or lifted from the soiled substrate.

Moreover, there is a crucial relationship between the critical amount of surfactant and cosurfactant, and the surface area of the grease clog. The typical drain trap (also called a "P-trap" because of its curved configuration) forms grease deposits having an elliptical shape. The ellipse has a long radius, R, of generally about .75-1.50 inches ( 1.905-3.81 cm), and a short radius, R', of about 0.25-.75 inches (.635-1.905 cm). This results in a surface area (A=RR'π) of grease clog of about 4.595.19cm ^: - 22.79cnr. Moreover, because this grease clog traps water, causing backflow and the commonly observed standing water, it has been empirically determined that the typical amount of drain opener delivered to said clog is a dilution of about 1 : 10 to 1 :50, most preferably about 1 :25. Thus, the present invention demonstrates that despite a relatively low level of active reaching the clog, there is an unexpectedly marked increase in grease dispersion/dissolution/digestion such that the clog is effectively removed after treatment with the cleaner and water flows smoothly through the draintrap once more.

3. Microorganisms and Enzvmes

In the practice of this invention, it is preferred to add fat. or rather, lipid-digesting microorganisms and enzymes which will be stable in the drain opener formulations of this invention. For example, as mentioned in EP 0 569 140 (incorporated by reference thereto), numerous microorganisms, such as Bacillus. Pseudomonas, Enterobacter and the like are useful for digesting the

lipids present in the grease clogs Especially preferred is Bacillus because of its lipid degrading characteristics as well as the fact that it, a gram positive rod, is a spore-former and thus is protected from attack from the external environment

When such microorganisms are present, it is additionally preferred to include a preservative so as to prevent or inhibit growth of contaminants Suitable preservatives include Kathon GC, a 5-chloro-2-methyl-4-ιsothιazohn-3-one, Kathon ICP, a 2-methyl-4-ιsothιazolιn-3-one, and a blend thereof, and Kathon 886, a 5-chloro-2-methyl-4-ιsothιazoiιn-3-one, all available from Rohm and Haas Company, Bronopol, a 2-bromo-2-nιtropropane 1.3-dιol, from Boots Company Ltd , Proxel CRL, a propyl-p-hydroxvbenzoate, from ICI PLC, Nipasol M, an o-phenvl-phenol. Na ^" salt, from Nipa Laboratories Ltd . Dowicide A, a l ,2-benzoιsothιazohn-3-one. from Dow Chemical Co , and Irgasan DP 200, a 2,4,4'-tπchloro-2-hydroxvdιphenylether. from Ciba-Geigy A G See also, Lewis et al , U S 4,252,694 and U S 4, 105,431, incorporated herein by reference Additionally preferred preservatives include alkyl (especially methyl) anthramlate, paraben and alkyl paraben Nutrients, such as lipids, carbohydrates, proteins, yeasts, etc , are also preferred

Additionally, hydrolase enzymes, such as proteases, amvlases, cellulases and lipases may be included Proteases are one especially preferred class of enzymes Thev are selected from acidic, neutral and alkaline proteases The terms "acidic," "neutral " and "alkaline." refer to the pH at which the enzvmes' activity are optimal An example of a neutral protease includes trypsin, a naturallv occurring protease Alkaline proteases are available from a wide vanetv of sources, and are typically produced from various microorganisms (e g , BaciUis subti sin) Tvpical examples of alkaline proteases include Maxatase® and

Maxacal® from International BioSvnthetics, Alcalase®. Savinase® and Esperase®. all available from Novo Nordisk A S See also Stanisiowski et al , U S 4 51 1.490 incorporated herein bv reference

Further suitable enzymes are amylases. which are carbohydrate-hydrolyzmg enzymes It is also preferred to include mixtures of amylases and proteases Suitable amylases include Rapidase®, from Societe

Rapidase, Termamyl® from Novo Nordisk A/S, Takatherm® from Solvay Enzymes, and Maxamyl® from International BioSynthetics

Yet other potentially suitable enzymes are hpases, such as those described in Silver, U S 3,950,277, Thorn et al , U S 4,707,291, Wiersema et al , U S 5,296, 161 and 5.030.240, all of which are incorporated herein by reference

Still further suitable enzymes are cellulases, such as those described in Tai, U S 4 479,881, Murata et al . U S 4,443,355, Barbesgaard et al . U S 4,435,307, and Ohva et al , U S 3,983 082. incorporated herein by reference

The hydrolytic enzyme should be present in an amount of about 0 0001 - 1 % (based on 100% active enzyme, most commercially vended enzymes are sold as liquids, slurries, prills or solids, in which either a liquid or solid filler/stabilizer is included, e g , propylene glycol) Mixtures of any of the foregoing hydrolases are desirable, such as protease/amylase blends

5 Organic Solvents

The solvent can be selected from both water soluble and water miscible organic solvents and from poorly water soluble organic solvents Some of the water soluble solvents include C, ₆ alkanol. C _{3 24} alkylene glycol ether, and mixtures thereof The alkanol can be selected from methanol. ethanol, n-propanol. isopropanol, butanol, pentanol. hexanol, their various positional isomers, and mixtures of the foregoing In the invention, it has been found most preferable to use isopropanol, usually in conjunction with a glycol ether It may also be possible to utilize in addition to. or m place of, said alkanols. the diols such as methylene. ethylene. propylene and butvlene glycols, and mixtures thereof The poorly soluble solvents can include such materials as d-hmonene, pine oil. and other terpene derivatives, such as terpene hydrocarbons (e g,s ,

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tertiary alcohols and ethers) and alicyclic hydrocarbons, such as methylcyclohexane

The amount of solvent present may vary from 0 to 50%, more preferably 0 to 10%, but such level is not critical

6 Builder

A builder may be selected from organic and inorganic builders, such as from the group consisting of ethylene diamine tetraacetates (EDTA), carboxvlates. such as citric, glutaπc or acetic acids (and their salts), alkali metal carbonates, alkali metal silicates, alkali metal phosphates, and mixtures thereof Optionally , a co-builder selected from ammonium, alkali metal and alkaline earth metal hydroxides, may be desirable Certain builders also act as buffers, both acidic and basic, and their inclusion may also be desirable herein As well, buffers, such as NaOH, H,SO ₄ , HC1, etc , may be desirable

The level of builder can be fairly low, but is not critical The amount herein can vary from about 0 to 15%, more preferably 0 to 5% In preferred compositions of this invention, the builder is below 1%

7 Water and Miscellaneous

Since the drain opener is an aqueous cleaner with relatively low levels of actives, the principal ingredient is water, which should be present at a level of at least about 50%, more preferably at least about 80%, and most preferably, at least about 90% Deionized water is most preferred

Small amounts of adjuncts can be added for improving cleaning performance or aesthetic qualities of the cleaner Adjuncts for cleaning include additional surfactants, such as those described in Kirk-Othmer. Encyclopedia of Chemical Technology. 3rd Ed . Volume 22, pp 332-432 (Marcel-Dekker. 1983), which are incorporated herein by reference Aesthetic adjuncts include fragrances, such as those available from Givaudan. IFF, Quest and others, and dyes and

pigments which can be solubilized or suspended in the formulation, such as diaminoanthraquinones. The amounts of these cleaning and aesthetic adjuncts should be in the range of 0-2%, more preferably 0-1%.

In the following Experimental section, the surprising performance benefits of the various aspects of the inventive cleaner are demonstrated.

EXPERIMENTAL

In the following experiments, it is demonstrated how the critical amount of surfactant present in the mventive dram openers provides surprisingly enhanced grease clog removal In order to demonstrate this phenomenon, the conditions in a kitchen dram trap were sought to be simulated so that the effect could be rigorously tested through repeated iterations

Example 1 As is known the conditions in drain traps varies from household to household, and situation to situation However, generally speaking, it has been observed that residents in households will pour melted fats and oils, such as butter, bacon fat, cooking oils and the like, even though often cautioned against so doing When the molten fats and oils meet the residual water in the drain, or, as is often the case, the water running from a spigot or faucet, these fats and oils solidify and begin to deposit on the closest horizontal surface, typically, the horizontal portion of a drain or P-trap Because the dram trap is a pipe of circular bore, the forming grease plug or clog molds into an elliptical mass, which eventually clogs the trap Previous drain cleaners, such as caustic chemicals, have been attempted with varying rates of success, since they will principally heat the standing water due to the exothermic heat of reaction from the combination of water and caustic

To simulate the foregoing typical grease clog, individual 5 g portions of

Cπsco brand vegetable shortening were melted and poured into individual 250 ml beakers which were canted at a 45° angle After the molten shortening hardened, this formed an elliptical grease plug All of the examples used this simulated grease plug which was found to be an excellent emulation of the grease clog found in drain traps

Examples 2-1 1 In these examples, ten different formulations, all with 3% total surfactant, were prepared In dosing the grease clog samples the formulations were each

diluted 1 25, smce it has been found that there is always standmg or residual water in dram traps, drain cleaners will be diluted prior to reaching the clog from 1: 10 to 1 50, with 1.25 dilution being very representative.

The formulations generally comprised a base formulation (shown in TABLE I below) combinations of surfactant A, which was a C, _{2 14} linear ethoxylated alcohol, with about 7 moles of ethylene oxide, cosurfactant B, which was a C ₁₂ . _M linear ethoxylated alcohol, with about 3 moles of ethylene oxide; and cosurfactant C, which was a tridecyl ether, with about 3 moles of ethylene oxide

TABLE I BASE FORMULATION

¹ Proxel

² Methvl anthramlate

^Λ sufficient quanutv of deiomzed water to make up 3780 ml of formulauon

TABLE II below shows the type and ratios of surfactants used

TABLE π

Example 2 3 4 5 6

Surfactant A 16.67% 16.67%

Cosurfactant 100% 50% 16.67% 66.67% B

Cosurfactant 100% 50% 66.67% 16.67% C

Example 7 8 9 10 11

Surfactant A 33.33% 50% 66.67% 50% 100%

Cosurfactant 33.33% 16.67% 50% B

Cosurfactant 33.33% 50% 16.67% ^c

The formulations were dosed onto the sample grease plugs in a 1:25 (vol. /vol.) dilution, with deionized water. These samples were allowed to sit for about 24 hours at room temperature (-21 °C), rinsed, dried and then weighed to determine grease removal. This procedure was repeated three times with each sample. The results after the third treatment are depicted in TABLE III below:

TABLE III

Example 2 3 4 5 6

% Grease 0.4 1.7 1.8 2.6 6.2 Lost

Example 7 8 9 10 11

% Grease 15.8 21.3 24.9 25.2 26.9 Lost

As can be seen from the foregoing TABLE DI, those examples (7-11) wherein the ratio of surfactant to cosurfactant was at least 1 :2 greatly outperformed the remaining examples (2-6) where the amount of surfactant to cosurfactant was less than 1 :2.

Further, it was observed that when the total level of surfactant/cosurfactant is greater than 6%, the grease removal performance was not enhanced and remained fairly static. This, too, was quite surprising, since it is known in hard surface cleaning that to increase the level of cleaning active, i.e., surfactant, linearly increases the cleaning performance.

In the next set of Examples, the effect of the level of surfactants was tested. As mentioned above, it has been observed that the invention's Total Surfactant Level is a critical level, in which exceeding the critical level will either not improve the grease-removing performance of the invention, or, in fact, may actually hamper the performance. Further, the type of surfactant used is significant. In these Examples, the base formulation exemplified in TABLE I was again utilized, with differing amounts of surfactants added. In Example 12, 3% total surfactant (a linear alkylbenzenesulfonate), was used. In Example 13, a ternary blend of surfactants (total surfactant level: 3%) similar to Example 7 was used. In Example 14, a ternary blend of surfactants similar to Example 7 was used, except that the total surfactant level was 6%.

TABLE IV

From TABLE IV, above, it can be seen that to use a different type of surfactant, in this case, an anionic surfactant in Example 12, will not achieve the same type of grease removal performance as achieved by the invention. Further, Example 14 is instructive in demonstrating that when the outer limit of the invention is reached, namely, to exceed 6% surfactant, then grease removal is not only not enhanced, it may actually be impaired. This was a very surprising finding, given that for hard surface cleaners, one can typically see a linear relationship between the amount of surfactant added and the amount of soil removed. TABLE V below demonstrates the performance of the invention versus currently available commercial formulations.

In TABLE V, Example 15 is a currently available commercial liquid drain buildup remover, which uses about 3% nonionic surfactants, which are ethoxylated nonylphenol ethers. Example 16 is representative of the invention and uses a ternary surfactant blend, just as in Example 7, above. Example 17 is another commercially available liquid drain buildup remover which, however, uses only about 0.5% total nonionic surfactant, which is expected to comprise ethoxylated nonylphenol ethers. Example 17 also is believed to contain a small amount of lipase enzyme. Apart from the stated surfactant and/or enzymes, Examples 15 and 17 will contain somewhat roughly similar ingredients as set forth in the Base Formulation, TABLE I.

TABLE V

Thus, the Examples in TABLE V demonstrate further demonstrate that the type and amount of surfactant have a bearing on whether optimal grease removal performance can be achieved.

The above examples have been depicted solely for purposes of exemplification and are not intended to restrict the scope or embodiments of the invention. The invention is further illustrated with reference to the claims which follow hereto.