LIQUID HARD SURFACE CLEANER RINSE
FIELD OF THE INVENTION
The present invention relates generally to hard surface cleaners for use on ovens, sinks, toilets, bath tubs, shower stalls and the like. More specifically, the present invention comprises a rinsing solution for keeping these areas clean and free of mineral and other types of hard to remove deposits.
BACKGROUND OF THE INVENTION Shower stalls, sinks, and tubs accumulate a steady build-up of organic and inorganic deposits on their surfaces as a result of repeated use. The accumulation of such deposits, which include insoluble soap residues, washed-off debris from the body that is often partially coated with soap or shampoo, calcium, magnesium carbonates and soaps, other insoluble metal salts, and growth of mildew and micro-organisms, creates an unsightly and unhealthy environment that is unacceptable from the standpoint of cleanliness and good hygiene, as well as aesthetics.
Conventionally, the build-up of deposits in a shower can be cleaned with any one of a number of aggressive cleaners commercially available to the consumer. These cleaners, which contain combinations of surfactants, builders, chelating agents, oxidizers, abrasives, and soluble salts, require repeated scrubbing or wiping with the cleaner, followed generally with a water rinse, to periodically remove the unsightly and unhealthy build-up in the shower. However, considerable labor is required to maintain a clean shower using these conventional cleaners.
United States Patent No. 4,020,016 to Sokol discloses aqueous cleaning compositions for dissolving soap curds that require a non-ionic surfactant having an HLB (hydrophilic-lipophilic balance) number of at least 13.5. The composition also comprises ammonium, alkylamine or
the hydroxy-alkylamine salt of nitrilotriacetic acid and an alkylene polyamine polycarboxylic acid as a chelating agent. The aqueous cleaning compositions are alleged to readily dissolve the soap curds with minimal manual effort. Soap curds form when the surfactants in the soap form complexes with metal ions and become insoluble. The composition is free of alkaline metal ions.
U. S. Patent No. 5,536,452 to Black teaches an aqueous rinsing composition for removing deposits from the surfaces of showers and the like without the need for manual scrubbing or wiping. The composition is comprised of a nonionic surfactant which has a hydrophilic-lipophilic balance number (HLB) of 13 or less, in particular, ethoxylated alcohol and ethoxylated alkylphenols, a chelating agent, an alcohol, and optionally, ammonium hydroxide and/or morpholine and water. U. S. Patent No. 5,587,022 also to Black discloses the same nonionic compositions as the '452 patent and further claims a method for rinsing showers using them.
These prior art compositions however, inherently possess a number of major flaws and deficiencies. Many plumbing components and fixtures used in shower stalls, bath tubs, sinks and toilets are comprised of one or a number of plastics such as polypropylene, polyvinyl chloride, polystyrene and the like. Nonionic surfactants such as the alcohol alkoxylates are hydrophobic with low solubility characteristics. As such, they soften and solubilize these plastic materials and result in cracking and crazing of the plastic surface. Crazing is a phenomenon caused by the solubilization and recrystallization of plastics whereby small, minute cracks are formed on coatings or glazed surfaces.
Secondly, the nonionic surfactants disclosed in the prior art with an HLB of 13 or less have very low cloud points and tend to form complexes with calcium and magnesium ions that are naturally found in tap water. These nonionic-metal complexes are insoluble and hence form deposits
on the very surfaces that the surfactant composition is supposed to clean. And to exacerbate the problem, these surfactants also have very poor lime soap dispersibility which is essential for the removal of the calcium and magnesium lauryls, palmitates, and stearates generally found in commercially available soaps that form a soapy scum or film on the kitchen and bathroom surfaces.
Finally, the nonionic surfactants used in the hard surface bathroom cleaners of the prior art are non-biodegradable, toxic and are irritating to the skin and eyes. Moreover, due to the surfactant's low solubility as indicated by their low cloud points, excessive amounts of alcohol are required to formulate them into concentrated products.
The present invention then is an improved liquid hard surface cleaner rinse in which the active surfactant is one or more unique nonionic or anionic ester polymer surfactants which have been found to be far more compatible with all types of plastics resulting in no cracking or crazing even after repeated use. These surfactants are also highly stable at all temperatures. They have extremely high cloud point values and therefore do not form calcium or magnesium ion complexes resulting in surface stains and deposits. They are biodegradable, non-toxic and hence more environmentally friendly in addition to being mild to the eyes and skin. They also have excellent lime soap dispersing power and improved surface cleaning capability so that no soapy scum residues are left after use. Moreover, they are much more soluble than the other surfactants requiring the addition of little to no alcohol in order to formulate the hard surface cleaner rinse composition.
There is a need then for a liquid hard surface cleaner rinse for use as a shower, bathtub, sink and counter top cleaner that may be easily applied to these surfaces as a rinse which readily removes soap scum, greasy films, dirt, mildew and microorganisms such as bacteria and
viruses which can grow and fester within these otherwise unsightly deposits. These superior cleaning attributes are achieved while the surfactants themselves are both compatible with the surfaces that are cleaned as well as being non-toxic, biodegradable and non-irritating. SUMMARY OF THE INVENTION
The present invention is an improved liquid hard surface cleaner comprising any one or more of a number of anionic or nonionic ester polymer surfactant compounds as the surface active agent that is particularly useful as a sink, bath or shower surface cleaner rinse. The composition may be comprised of the anionic or nonionic polymer surfactant(s) with water as the carrier solvent alone or, preferably, will also include a chelating or sequestration agent, an acid or base solvent, other secondary surfactants, fragrances, and/or disinfectants. The compositions provide superior cleaning functions while at the same time are non-toxic, biodegradable and much more compatible with plastic surfaces so as to not only clean but protect the surfaces from other, less compatible compounds.
DETAILED DESCRIPTION OF THE INVENTION
The liquid hard surface cleaner rinse compositions of the present invention consist of an anionic or nonionic surface active polymer, water, and a number of other optional ingredients which can vary as desired by the formulator depending on the particular application, strength necessary, etc. Taken in their broadest aspect, the nonionic or anionic ester polymer surfactants of the present invention comprise an oligomeric ester backbone which is preferably end-capped on at least one end, more preferably both ends, of the backbone by end-capping units. The end- capping units are anionic hydrophiles, connected to the ester backbone by means of aryl groups or by an ester or ether linkage. Preferably, the anion source is a sulfonated group.
Polymers of the subject invention encompass oligomeric (low molecular weight polymeric), substantially linear uncapped or end-capped esters. These esters comprise, in their backbones, oxyalkyleneoxy, preferably oxy-1 ,2-propyleneoxy and oxyethyleneoxy units, and hydrophobic aryldicarbonyl, preferably terephthaloyl units. Preferred esters additionally comprise units of sulfosophthalate and, optionally, poly(oxyethylene)oxy units having a degree of polymerization from about 2 to about 4. Mixtures of such esters with reaction by-products and the like retain their highly effective surface active properties when such mixtures contain at least about 10%, preferably at least about 25%, more preferably at least about 50%, by weight, of the subject esters. The esters useful herein are of relatively low molecular weight (i.e. generally below the range of fiber-forming polyesters) typically ranging from about 500 to about 20,000, preferably from about 550 to about 8000, also preferably from about 650 to about 2500.
Preferred end-capping units include sulfoaroyl units, especially sulfobenzoyl units of the formula (MO3S)(C6H4)C(0)- wherein M is a salt- forming cation such as sodium or tetraalkylammonium. Preferably M is sodium. Preferably not more than 0.15 mole fraction of the sulfobenzoyl end-capping units are in para-form. More preferred are the sulfobenzoyl end-capping units being essentially in ortho- or meta-form.
Other preferred end-capping units include those derived from sulfonated polyethoxy/propoxy groups, which are connected to the backbone by an ester linkage. Preferred are those of the formula (M03S)(CH2)m(RO)n-, wherein M is a salt-forming cation such as sodium or tetraalkylammonium; m is 0 or 1 , preferably 0; R is ethylene, propylene, or a mixture thereof, preferably ethylene; and n is on average from 1 to about 20, preferably about 1-5. More preferred are capping
units derived from monomers selected from the the group comprising sodium 2-(2-hydroxyethoxy) ethanesulfonate, sodium
2-(2(hydroxyethoxy)ethoxy)ethanesulfonate, and
2-(2-(2-(hydroxyethoxy)ethoxy)ethoxy)ethanesulfonate. Still other preferred end-capping units include ethoxylated or propoxylated phenolsulfonate units of the formula MO3S(C6H4)(OR)p- wherein M and R are as defined above, and p is a number of from about 1 to about 20, preferably from about 2 to about 10.
Additionally suitable preferred end-capping units include modified poly(oxyethylene)oxy monoalkyl ether units of the formula
R"O(CH2CH2O)k- wherein R" is about C C4, preferably about CrC2 saturated alkyl, and k is a number of from about 3 to about 100, preferably from about 5 to about 50.
Preferred end-capped esters are essentially in the double end- capped form, comprising about 2 moles of the end-capping units per mole of the ester.
The ester "backbone" of the surfactant polymers, by definition, comprises all the units other than the end-capping units, all the backbone units incorporated into the esters being interconnected by means of ester bonds.
The essential oxyalkyleneoxy units of the backbone of the subject polymers are mixtures of symmetrical (a) -OCH2CH2O- (oxyethyleneoxy) units with unsymmetrical (b) -OCH(Ra)CH(Rb)O- (oxy-1 ,2-alkyleneoxy) units, wherein Ra and Rb are selected so that in each of the units, one of Ra or R is H and the other is a non-hydrogen R group (as specified below), or Ra and R can be different non-hydrogen R groups. With respect to preferred (b) units, one of Ra or Rb is H. The (b) units are
believed to provide a sufficiently unsymmetrical character required for stability of the desired viscosity of the anionic or nonionic surfactant polymers, whereas the (a) units are believed to provide sufficient symmetry for superior surface active functionality. A convenient measure of the unsymmetrical character required is given by the mole ratio of (a) units to (b) units. For the subject invention processes, the ratio of (a) units to (b) units in the subject polymers preferably varies from about 1 :2 to about 4:1. At a ratio of greater than about 4:1 , the polymers spontaneously change from an amorphous character to a crystalline form quickly, and are not useful in commercial scale processes where concentrated aqueous solutions are prepared and kept for more than a few minutes. At a ratio less than about 1 :2, the polymers have little tendency to change from amorphous to crystalline form. More preferred ratios of (a) units to (b) units in the subject polymers is from about 1 :1 to about 3:1 , more preferred still from about 1.3:1 to about 2:1.
In the above paragraph, R is preferably a non-hydrogen, non- charged group with a low molecular weight (typically below about 500). R is chemically unreactive (especially in that it is a non-esterfiable group) and is comprised of C and H, or of C, H and O. The preferred R groups are selected from lower n-alkyl groups, such as methyl, ethyl, propyl and butyl, especially methyl. Thus, the preferred oxy-1 ,2-alkyleneoxy units are oxy-1 ,2-propyleneoxy, oxy-1 ,2-butyleneoxy, oxy-1 ,2-pentyleneoxy and oxy-1 , 2-hexyleneoxy units. Especially preferred are oxy-1 ,2- propyleneoxy as (b) units. The backbones of the subject esters comprise, per mole of ester, from about 0.5 to about 66 moles of the oxyalkyleneoxy units, preferably from about 1 to about 22 moles, more preferably from about 3 to about 16 moles.
Certain non-charged, hydrophobic aryl dicarbonyl units are also in the backbone of the subject polymers. Preferably, these are exclusively terephthaloyl units. Other non-charged, hydrophobic dicarbonyl units, such as isophthaloyl, adipoyl, or the like, can also be present if desired, provided that the soil release properties of the esters (especially polyester substantivity) are not significantly diminished. These other, non-charged, hydrophobic dicarbonyl units can aid in providing sufficient irregularity in the subject esters to avoid a too great tendency to crystallize.
The backbones of the subject esters comprise, per mole of ester, from about 1 to about 40 moles of the hydrophobic aryl dicarbonyl units, preferably from about 2 to about 24 moles, more preferably from about 3 to about 14 moles.
Generally, if it is desired to modify the units of the esters, use of additional hydrophilic units is preferred over the use of additional, non- charged, hydrophobic units. To this end, minor amounts, preferably comprising less than about 5% of the molecular weight of the ester, of additional units such as di- or tri- (oxyethylene)oxy units are incorporated into the esters.
It is also possible to introduce charged, hydrophilic units into the backbone; preferably such units comprise less than about 20%, more preferably less than about 14% of the backbone units. One example is to incorporate a charged moiety Rcin place of one or more Ra or Rb moieties of the above oxy-1 ,2-alkyleneoxy units. Such Rc moiety preferably has the structure MO3SL-, wherein M is a salt-forming cation such as sodium or tetraalkylammonium, and L is a side chain connecting moiety selected from alkylene, oxyalkylene, alkyleneoxyalkylene, arylene, oxyarylene,alkylomeoxyarylene,poly(oxyalkylene), xyalkyleneoxyarylene, poly(oxyalkylene)oxyarylene, alkylenepoly(oxyalkylene), and mixtures
thereof. As used in this paragraph, alkylene are about C2-C6, preferably ethylene or 1 ,2-propylene; arylene is preferably phenylene.
As another example, anionic hydrophilic units capable of forming two ester bonds may be included in the backbone of the esters. Suitable anionic hydrophilic units of this specific type are well illustrated by sulfonated dicarbonyl units, such as sulfosuccinyl, i.e., or more preferably, sulfoisophthaloyl, i.e., -(0)C(C6H3)(SO3M)C(0)- wherein M is a salt- forming cation, such as an alkali metal or tetraalkylammonium ion.
The backbones of the subject esters comprise, per mole of ester, from 0 moles to about 20 moles of sulfonated dicarbonyl units, preferably from about 0.5 moles to about 9 moles, more preferably from about 1 mole to about 4 moles.
The anionic and nonionic low molecular weight poly(oxyethylene) oxy/aryldicarbonyl ester polymer surfactants are incorporated in the rinse formulations in an amount of from about 0.01 wt. % to about 5.0 wt. % based upon the total weight of the rinse formulation. Preferably, the ester polymer in an amount of 2.0 wt. % to 5.0 wt. %
The other ingredients that may optionally be added may include, for example, amphoteric surfactants such as betaines, sultaines, amphopropionates, amine oxides and carboxylates. The surfactants which have been found to provide the benefits of the invention can be represented by the formulae:
I R2
R.
II. R-N
R5YM
(R6OH)x
/
III. R-NΘ-R5COO-
\ (R5 COOM) 2_x
IV. R, I
R-Nθ -0"
I R2
and mixtures thereof as well as mixtures with other surfactants wherein R is selected from the group of alkyl, alkylarylalkyl, arylalkyl, alkylaminoalkyl and sulfonated derivatives thereof, alkylamidoalkyl, or alkoxylalkyl, and the hydroxy-substituted derivatives thereof wherein the alkyl group contains from about 1 to about 16 carbon atoms, the aryl group is up to and including two fused rings and the alkoxy group contains from 4 to 18, preferably 4 to 10, carbon atoms wherein the total carbon atom content of the R group is no more than about 18 carbon atoms. R can be butyl, hexyl, 2- ethylhexyl, octyl, capryl, caprylyl, coco, lauryl, palmitic and the like. Substituents from natural sources contain mixed carbon chain lengths or can be purified to reduce the number of chain lengths in the alkyl groups. R can also be alkylamidoalkyl, such as butylamidoethyl or caprylamidopropyl, cocoamidopropyl and alkoxyalkyl such as cocooxypropyl, decyloxypropyl, hexyloxymethyl or hexyloxy -2- hydroxy- propyl. R can also be
V. R7-CH (OH) CH2-Q-
R., and R2 independently represent alkyl chains of from about 1 to about 6 carbon atoms, preferably methyl, and the hydroxy-substituted derivatives thereof or hydroxy polyoxyethylene, polyoxypropylene or mixed polyether polymers of EO and PO having no more than 20 ether linkages; or R, and R2 may jointly be -CH2CH2OCH2CH2- or -CH2CH2SCH2CH2- so as to form together with the nitrogen atom a morpholine or thiomorpholine ring. R3 represents an alkyl or hydroxy- substituted alkyl group of from 1 to about 4 carbon atoms; R4 represents R6OH, R5YM, preferably R5COOM, or hydrogen where R6 is a lower alkyl of from 1 to about 4, preferably 2, carbon atoms and the hydroxy- substituted derivatives thereof; R5 represents alkyl or hydroxy-substituted alkyl of from 1 to about 4, preferably 1 or 2 carbon atoms; Y represents COO" or SO3 "; M represents hydrogen and or an alkali metal such as sodium or potassium and x equals 1 or 2.
Preferably, the surfactants are low to moderate foaming or non- foaming as foaming creates difficulties when used as a cleansing rinse, i.e. foams will not readily flow as a rinse off the surface to be cleaned thereby leaving residue. The compounds of Formula I generally defined as betaines and sultaines are well known compounds and can be made by well known methods. Betaine is trimethyl glycine. Replacing one of the methyl groups provides a betaine derivative, commonly an alkyl betaine. Betaines are zwitterionic and internally compensated salts. The remaining two methyl groups can be replaced such as with hydroxyethyl groups to form dihydroxyethyl alkyl glycinate.
In betaines, R is C4 to C16 alkyl, alkylamidoalkyl or alkoxyalkyl. The alkyl group or portion of the group is preferably about C4 to about C10. R^ and R2 are preferably methyl. When R., and R2 are not methyl, they can
optionally be substituted with an electron withdrawing group such as OH, SH, CH3O or, CH3S.
Materials which employ a sulfonate or hydroxy alkyl sulfonate in place of the carboxyl group, by analogy, are described as sultaines. These are well known compositions.
A specific group of sultaines that have been found to be effective in the invention can be more specifically depicted by the general formula:
VI. R
7-CH (OH) CH
2-Q-NΘ-R
3-SO
3-
I
R2
wherein R7 is selected from alkyl, aryl, or alkylaryl groups of from about 4 to about 16 carbon atoms or alkoxymethylene wherein the alkoxy group contains from about 4 to about 8 carbon atoms; R^ and R2 are as defined hereinbefore with the proviso that when the alkyl group is an alkyl of from about 2 to about 6 carbon atoms, the alkyl group is substituted by an electron-donating group on the beta carbon atom thereof. R3 represents an alkyl or hydroxy-substituted alkyl group of from 1 to 4 carbon atoms. Q is a covalent bond or:
R8 X
VII. I I -N-(CH2)nCHCH2-
wherein R8 is hydrogen or -CH2CH(OH)CH2SO3M where M is hydrogen or an alkali metal cation; n is 0 or 1 and X is hydrogen or an electron- donating group such as OH, SH, CH3O or CH3S. Typically the R7 group contains from about 4 to about 14, commonly from about 4 to about 8 carbon atoms. Preferably, R7 is
alkoxymethyl containing from about 4 to about 8 carbon atoms in the alkoxy group such as butoxymethyl, hexyloxymethyl, 2- ethylhexyloxymethyl and the like. R1 and R2 are each preferably methyl, hydroxyethyl, 2-hydroxypropyl, or a morpholine ring. When Q is not a covalent bond, X is preferably hydrogen and n is preferably 1. Q is preferably a covalent bond. A particularly preferred group of compounds can be described as alkylether hydroxypropyl sultaines.
All of these surfactants are more fully described in and can be prepared by processes disclosed in U.S. Pat. No.4,891 ,159, the entire disclosure of which is incorporated herein by reference.
This group of surfactants can typically be incorporated in aqueous solutions that can have high acid or alkaline content, particularly having a relatively high alkali content, for example, within the range of from 5 to about 50%, and preferably from about 25 to about 50% sodium or potassium hydroxide or equivalent such as strong sodium carbonate, silicate and phosphate solutions.
Compounds of this class which can be used in the invention include the following which are believed to be predominantly of the formulae: OH I
C 2,H' '5 OH CH2-CH-CH2S03-Na
C ■ 4H' 'Q9-CH-CH,O-CH,-CH-CH,-N CH3 OH
(CH2)3NffiCH2CH-CH2SO3
CH3
OH CH, OH
C ■ 4H1 'c9-CH,CH-CH,-Na -CH2CH-CH2S03-
CH,
OH CH3 OH
CaHqCH-CH,0-CH,CH-CH,-NθCH,CH-CH,SO.
CH,
OH CH3 OH
CH,
CH3 OH
RC(O)NHCH2CH2CH2Nθ-CH2CH-CH2S03
I
CH '33
CH2- CH(OH)CH2-SO3Na
I
R-O CH2CH(OH)CH2-N-(CH2)3-Nffi-(CH3)2-CH(OH)CH2SO3-
wherein R represents the residue of glycidyl ether of a lauryl myristyl alcohol mixture.
Within Formulas II and III are numerous compositions that can be defined as imidazoline derivatives, preferably where R is alkylamidoalkyl, which are well known and can be made by well known methods. These are true amphoteric surfactants as they are anionic above the isoelecthc point, cationic below the isoelecthc point and zwitterionic in the isoelecthc range. These compounds have at least two sites capable of ionization or protonization, i.e., a tertiary amine, carboxylate or sulfonate group with electronegative charge.
An alkylamphoacetate or propionate as used in the invention, such as capryl, coco or tallow, at alkaline pH is an anionic surfactant as represented below:
CH2COO- Naθ
I RC(0)NH CH2CH2N I
CH2CH2OH
At acid pH, the carboxylate group ionization is suppressed, the amine group is protonated by the excess hydrogen ions and the result is a cationic material:
CH2COOH
I
RC(0)NH CH2CH2NΘH
I CH2CH2OH
In the isoelecthc range, both sites are ionized and a zwittehon is formed:
CH2COO"
I RC(0)NH CH2CH2NΘH
I
CH2CH2OH
In similar manner, the compounds of Formula III likewise are capable of different ionic forms depending on pH as illustrated by the following preferred compounds:
Alkylamphodicarboxylates (e.g., diacetates and dipropionates)
CH2COOH
I
RC(O)NH CH2CH2NθCH2COOH
I CH2CH2OH
Acid pH - Cationic
CH2COO Naθ
I RC(O)NH CH2CH2NθCH2COO-
CH2CH2OH
Alkaline pH - Anionic
CH2COO'
I
RC(O)NH CH2CH2NθCH2COOH
I
CH2CH2OH Neutral pH - Zwitterionic
The inclusion of the various ionic possibilities of compounds in Formula II and III includes the sulfonated derivatives as well as the carboxylated derivatives.
Included within Formula II of the invention are the amino and imino-carboxylates which are well known and also vary ionic form depending on pH.
Alkylaminopropionates
RNH2ΘCH2CH2COOH
Acid pH - Cationic
RNH2ΘCH2CH2COO-
Neutral pH - Zwitterionic
RNHCH2CH2COO Naθ
Alkaline pH - Anionic Alkyliminodipropionates
CH2CH2COOH CH2CH2COO- CH,CH,COO-Naθ
I I
RNHΘ RNHΘ RNHΘ
I
CH2CH2COOH CH2CH2COOH CH2CH2COO Naθ Acid pH Neutral pH Alkaline pH Cationic Zwitterionic Anionic
The above compounds differ from the imidazoline-dehved materials since they have no amide group and differ from the betaines since the nitrogen is not quaternized. These ionic variations are intended to be included within the formula defining the compounds useful in this invention.
Typically, liquid hard surface cleaner rinse solutions utilized in accordance with the invention can contain the amphotehc surfactants in amounts ranging from 0.1 to 5.0%, and preferably from about 0.1 to 3.0%, active percent by weight of the solution. Concentrated solutions, generally designed for dilution can contain higher percentages, such as up to about 40% active weight percent of the surfactants. As discussed supra, these can be comprised solely of surfactant and water but preferably will also comprise additional components. In addition to the amphotehc surfactant component of the hard surface cleaner rinse compositions of the present invention, other additional components are preferably added for best results. These comprise a sequesterant or chelating agent, a hydrophilic solvent and an acid or a base which is added in order to increase or decrease the pH of the liquid cleaner composition as required by local environmental conditions. Optional ingredients such as buffers, fragrances, disinfectants, colorants for visual aesthetics and other secondary surfactants for increased surface active cleaning power may also be included.
Preferably, the chelating or sequestration agent is ethylene diamine tetraacetate (EDTA) or one of its salts such as diammonium EDTA, a commercially available 44% solution that is easy to mix, economical in cost, and has low toxicity. Other chelating agents that may be used are, for example but not limited to, hydroxyethyl ethylene
diaminethacetic acid (HEEDTA), propanolamine, polyamino-carboxylic acid, diethylenethamine pentacetic acid (DTPA) and nitrolothacetic acid (NTA) can be substituted for EDTA or diammonium EDTA on an equivalent chelating strength basis. The chelating or sequestering agent is preferably mixed in the liquid hard surface cleaner in an amount of about 0.01 wt. % to 5.0 wt. % based on the total weight of the liquid cleaner rinse. On an equivalent chelating strength basis, the other chelating agents mentioned above, as well as a solution of diammonium EDTA of different concentration, can be mixed in the liquid hard surface cleaner rinse composition in an amount of about 0.1 wt. % to 3.0 wt. %.
A base or acid may be incorporated in the composition to increase or decrease the pH of liquid hard surface cleaner rinse depending on the acidity or alkalinity required for the cleaning conditions; i.e. water hardness, etc. The pH of the aqueous shower rinsing solution is preferably in the pH range of about 3 to 10, more preferably in the pH range of from about 5.0 to 9.0.
A hydrophilic solvent, which increases the solvent properties and improves the sheeting action of the rinse by keeping the viscosity low in order to minimize any residual film on both sink and shower surfaces, can optionally be added to the liquid hard surface cleaner rinse in the range of about 0.5 wt. % to about 5.0 wt. % of the total weight of the cleaner rinse. Any short-chain alcohol, such as ethyl alcohol, isopropyl alcohol, n-propyl alcohol, n-butyl alcohol, and isobutyl alcohol, can be used, although isopropyl alcohol is preferred. Ethylene glycol, propylene glycol, glycerol, the isopropyl ether of ethylene glycol or the ethyl ether of ethylene glycol can be used as possible substitutions for a short-chain alcohol.
A builder is also optionally added as a buffer for the system according to the hardness of the tap water. These are selected from the
group comprising silicates, citrates, phosphates, pyrophosphates and polyphosphates, borates, amines and mixtures thereof. The amount added may vary according to local conditions but generally ranges from about 0.01 wt. % to about 3.0 wt. %. The liquid hard surface cleaner rinse preferably contains one or more fragrances to provide a fresh and clean smell. Although the addition of fragrance is optional, it satisfies the expectation of consumers that a clean shower, bath, toilet or sink would smell "fresh and clean". However, a composition which lacks a fragrance additive still performs satisfactorily in cleaning the bath, sink, or shower surfaces.
Pine scent is the preferred fragrance. However, any of a number of commercially available fragrances or color additives may be used to provide a fresh and clean smell and is well within the skill of those in the art. Generally, 0.005% to 0.008% of fragrance additive is mixed with the aqueous rinsing solution composition based on the initial concentration of the fragrance additive supplied by the manufacturer.
The water used in this liquid hard surface cleaner rinse of the present invention should have negligible amounts of metal ions and be capable of not leaving any residue or deposit after evaporation from a shower surface. Distilled water or deionized water is preferred as the source of water for dilution of the individual components as well as for the water added as the balance of the composition for an aqueous shower rinsing solution.
Local conditions, such as the degree of water hardness, altitude above sea level, and the composition of the indigenous soils, should also be taken into consideration in formulating the liquid hard surface cleaner rinse composition. The amount of surfactant, sequestration or chelating agent, buffer, hydrophilic solvent and acid or base incorporated may be increased/decreased to account for greater/lesser water hardness and
soils with higher/lower calcium and magnesium levels. At higher altitudes, alcohols having lower vapor pressure can be used.
The liquid hard surface cleaner rinse is a dilute amphotehc surfactant solution containing additional additives and the bath, shower or sink is rinsed after use to prevent the build-up of deposits. The rinsing solution is best sprayed on the surfaces of shower stalls, bath tubs, sinks, and toilets with a pump or pressurized sprayer. For superior results, the rinsing solution is applied to bath, shower or sink surfaces before the deposits dry and set. While the rinsing solution does soften and remove dried deposits, it works best in the removal of deposits that are still wet. The rinsing solution transports these undesirable deposits down wet surfaces by gravity and onto the bath, shower or sink drain. In subsequent uses of the sink, bath or shower, hot water and mist enhances the removal of deposits. Thus, the repeated cycles of spray application, drying of surfaces and subsequent showering or bathing serve to readily release the deposits from the surface and carry them down to the bath, sink or shower drain in a continuous fashion. Water rinsing other than the actual use of the bath, sink or shower itself can also be done but is not necessary. No scrubbing, wiping, or other mechanical action is necessary, in contrast to conventional cleaning agents which are used to remove deposits only after such deposits have dried.
Previously accumulated build-up of undesirable deposits that have already dried and set can be softened and completely removed, albeit gradually, with continued application of the rinsing solution after each use of the respective bath, shower or sink. While no wiping or other mechanical action is required to remove such previously dried and set deposits, gentle wiping accelerates the removal of softened deposits that have accumulated over a period of time.
Furthermore, in contrast to simply rinsing the shower surfaces with plain tap water or soapy water, both of which leave deposits, the present invention prevents streaking and air dries spot free. Thus, the aqueous hard surface cleaner rinsing solution provides a product for maintaining baths, sinks, and showers clean with the minimum of effort.
The following example is provided to better describe the benefits of the compositions of the present invention and their use. They are for illustrative purposes only, and it is recognized the minor changes and alterations can be made that are not contemplated herein. It is to be understood then that to the extent any such changes do not materially alter or vary the final composition and its efficacy, it is to be considered as falling within the spirit and scope of the invention as later recited in the claims.
Example 1 Hard surface rinse cleaners of the present inventions were compared to those of the prior art in terms of the degree to which a particular cleaner caused cracking and/or crazing of the plastic surface and in terms of each formulation's ability to remove soap scum, dirt, greasy film etc. Each of the surfactants tested was formulated as a standard rinse solution consisting of the following components in their respective amounts. The solutions were then repeatedly applied to a number of plastic surfaces in a standard dishwasher at 80°C and observed at intermittent intervals of 1 hour for 24 cycles (24 hours).
a) Surfactant 1.5 wt. % b) Isopropyl Alcohol 4.4 wt. % c) EDTA 1.5 wt. %
) Water Q.S.
OBSERVED VISUAL
SURFACTANT PERCENTAGE SURFACE
CRACKING/ APPEARANCE
CRAZING (Integrity/
Cleanliness)
1 ) Water (control) 15% Good
2) Nonionic Alcohol Alkoxyiate 55% Good
3) Sodium Oleate Ester 70% Very Poor
4) Alkyl Phenol Glycol Ether 75% Very Poor
5) Alkyl Phenol Glycerol Ether 60% Poor
6) Silicone Polyalkoxylate Block 80% Very Poor Copolymer
7) Amphoacetate/Amphopropionate 0% Excellent Surfactant Blend (MIRANOL JS) *
8) Capryloamphopropionate Sulfonate 2.0% Excellent
9) Capryloamprocarboxy Propionate 5.0% Excellent
10) Alkylether hydroxypropyl Sultaine 0% Excellent
11) Poly(oxyethylene)oxy/aryl 5.0% Excellent dicarbonyl ester polymers
RHODIA INC., CRANBURY, N. J.
As is made quite clear above, the amphotehc hard surface cleaner rinses of the present invention (no. 11) substantially outperformed those of the prior art (nos. 2-5). Not only are the amphotehc surfactants more compatible with the plastic surfaces resulting in less cracking and crazing, they were more effective in removing soap scum, films, and other visually discernible deposits.