EP3263681A1

EP3263681A1 - Liquid acidic hard surface cleaning compositions providing improved treatment of metal surfaces

Info

Publication number: EP3263681A1
Application number: EP16176326.3A
Authority: EP
Inventors: Anna Asmanidou; Coralie Paule Jeannine NAUDIN; Stefano Scialla; Jan-Sebastiaan Uyttersprot
Original assignee: Procter and Gamble Co
Current assignee: Procter and Gamble Co
Priority date: 2016-06-27
Filing date: 2016-06-27
Publication date: 2018-01-03
Anticipated expiration: 2036-06-27
Also published as: EP3263681B1

Abstract

Liquid acidic hard surface cleaning composition comprising certain polyvinylpyrrolidone copolymers provide good limescale removal and shine on chromed and stainless steel surfaces.

Description

TECHNICAL FIELD

The present invention relates to acidic liquid compositions for cleaning a variety of hard surfaces such as hard surfaces found in around the house, such as bathrooms, toilets, garages, driveways, basements, gardens, kitchens, etc., the acidic liquid compositions being particularly suited for treatment of metal surfaces such as chromed surfaces and stainless steel surfaces.

BACKGROUND OF THE INVENTION

Liquid compositions for cleaning limescale from hard-surfaces have been disclosed in the art. Limescale deposits, are formed due to the fact that tap water contains a certain amount of solubilised ions, which upon water evaporation eventually deposit as salts such as calcium carbonate on hard surfaces. The visible limescale deposits result in an unaesthetic aspect of the surfaces. The limescale formation and deposition phenomenon is even more acute in places where water is particularly hard. Furthermore, limescale deposits are prone to combination with other types of soils, such as soap scum or grease, and can lead to the formation of limescale-soil mixture deposits (limescale-containing soils). The removal of limescale deposits and limescale-containing soils is herein in general referred to as "limescale removal" or "removing limescale". Films and streaks may be left which results in poor shine, and an impression that the surface is not yet sufficiently clean. Such films and streaks are particularly noticeable on chromed and stainless steel surfaces, and are particularly difficult to remove without avoiding damage to the surface. Surface active polymers, such as polyvinylpyrrolidone and polycarboxylates have been formulated into acidic cleaners to improve shine on ceramic surfaces. However, such polymers have been found to be less effective on such chrome and stainless steel surfaces, leading to greater scrubbing being required and hence more risk of damage to the metal finish.
As such, a need remains for hard surface cleaning compositions which are more suitable for removing limescale and providing improved shine on chromed surfaces and stainless steel surfaces.
EP1531671 A1 relates to a disinfectant with residual antimicrobial activity comprises an organic acid, water and a polymer, which is preferably either a copolymer of vinyl pyrrolidone with another monomer such as vinyl acetate, acrylic acid, methacrylic acid or vinyl caprolactam; or poly(vinyl pyrrolidone); or it is a copolymer of an alkyl/alkoxy vinyl ether with maleic acid or an ether thereof. EP0957156 A1 relates to liquid acidic cleaning compositions suitable for cleaning bathroom surfaces comprising a homo or copolymer of vinylpyrrolidone, or a mixture thereof, a polysaccharide polymer, or a mixture thereof, an anionic surfactant, and an acid. WO 2004/016087 A1 relates to compositions which comprise a polymer capable of forming a complex with an organic acid, for providing a broad spectrum antimicrobial benefit.

SUMMARY OF THE INVENTION

The present invention relates to a liquid acidic hard surface cleaning composition having a pH of from 1.5 to less than 7, and comprising: a vinylpyrrolidone copolymer, a nonionic surfactant, and an organic acid system. The present invention further relates to the use of a hard surface composition comprising the copolymer of vinylpyrrolidone for providing improved shine to a chromed surface or stainless steel surface.

DETAILED DESCRIPTION OF THE INVENTION

The present compositions provide good limescale removal and long lasting shine over a wide range of surfaces. When formulated with the preferred acid systems, the acidic cleaning compositions provide good cleaning and long lasting shine, with little or no damage to delicate surfaces, especially metal surfaces such as stainless steel and chrome.

The liquid acidic hard surface cleaning composition

The compositions according to the present invention are designed as hard surfaces cleaners. The compositions according to the present invention are liquid compositions (including gels) as opposed to a solid or a gas.
The liquid acidic hard surface cleaning compositions according to the present invention are preferably aqueous compositions. Therefore, they may comprise from 70% to 99% by weight of the total composition of water, preferably from 75% to 95% and more preferably from 80% to 95%.
The compositions herein may have a water-like viscosity. By '"water-like viscosity" it is meant herein a viscosity that is close to that of water. Preferably the liquid acidic hard surface cleaning compositions herein have a viscosity of up to 50 cps at 60rpm, more preferably from 0 cps to 30 cps, yet more preferably from 0 cps to 20 cps and most preferably from 0 cps to 10 cps at 60rpm¹ and 20°C when measured with a Brookfield digital viscometer model DV II, with spindle 2.
In other embodiments, the compositions herein are thickened compositions. Thus, the liquid acidic hard surface cleaning compositions herein preferably have a viscosity of from 50 cps to 5000 cps at 10 s^-1, more preferably from 50 cps to 2000 cps, yet more preferably from 50 cps to 1000 cps and most preferably from 50 cps to 500 cps at 10 s^-1 and 20°C when measured with a Rheometer, model AR 1000 (Supplied by TA Instruments) with a 4 cm conic spindle in stainless steal, 2° angle (linear increment from 0.1 to 100 sec^-1 in max. 8 minutes). Preferably, the thickened compositions according to this specific embodiment are shear-thinning compositions. The thickened liquid acidic hard surface cleaning compositions herein preferably comprise a thickener, more preferably a polysaccharide polymer (as described herein below) as thickener, still more preferably a gum-type polysaccharide polymer thickener and most preferably Xanthan gum.
The liquid acidic hard surface cleaning composition of the present invention comprises a vinylpyrrolidone copolymer, nonionic surfactant, and an organic acid system.
Preferably, the weight ratio of organic acid to vinylpyrrolidone copolymer is from 50:1 to 500:1, preferably from 100:1 to 350:1, more preferably from 250:1 to 300:1. Preferably, the weight ratio of nonionic surfactant to vinylpyrrolidone copolymer is from 20 to 200, preferably from 40 to 150, more preferably from 50:1 to 100:1.

The vinylpyrrolidone copolymer:

The hard surface cleaning composition of the invention can comprise the vinylpyrrolidone copolymer at a level of from 0.001% to 2.0%, more preferably from 0.01% to 1.0%, yet more preferably from 0.02% to 0.10%, most preferably from 0.025 to 0.05% by weight of the cleaning composition, of the copolymer
Suitable vinylpyrrolidone copolymers can have the following structure:
wherein:

x is from 20 to 99 mol%, preferably from 40 to 99 mol%;
y is from 1 to 80 mol%, preferably from 1 to 40 mol%;
z is from 0 to 50 mol%, preferably 0 mol%;
such that (x+y+z) = 100;
R₁ is H or CH₃;
Z is O or NH;
R₂ is C_aH_2a, wherein a is from 1 to 4, preferably 2;
R₃ is independently C₁ to C₄ alkyl; and
M is a vinyl or vinylidene monomer, preferably copolymerisable with vinyl pyrrolidone other than the monomer identified in [ ]_y.

Such vinylpyrrolidone copolymers are more fully described in United States Patent No. 4,445,521 , United States Patent No. 4,165,367 , United States Patent No. 4,223,009 , United States Patent No. 3,954,960 , as well as GB1331819 .
The monomer unit within [ ]_y is, for example, a di- alkylamine alkyl acrylate or methacrylate or a vinyl ether derivative. Examples of these monomers include dimethylaminomethyl acrylate, dimethylaminomethyl methacrylate, diethylaminomethyl acrylate, diethylaminomethyl methacrylate, dimethylaminoethyl acrylate, dimethylaminoethyl methacrylate, dimethylaminobutyl acrylate, dimethylaminobutyl methacrylate, dimethylaminoamyl methacrylate, diethylaminoamyl methacrylate, dimethylaminohexyl acrylate, diethylaminohexyl methacrylate, dimethylaminooctyl acrylate, dimethylaminooctyl methacrylate, diethylaminooctyl acrylate, diethylaminooctyl methacrylate, dimethylaminodecyl methacrylate, dimethylaminododecyl methacrylate, diethylaminolauryl acrylate, diethylaminolauryl methacrylate, dimethylaminostearyl acrylate, dimethylaminostearyl methacrylate, diethylaminostearyl acrylate, diethylaminostearyl methacrylate, di-t-butylaminoethyl methacrylate, di-t-butylaminoethyl acrylate, and dimethylamino vinyl ether.
Monomer M, which is optional (z is up to 50) can comprise any conventional vinyl monomer copolymerizable with N-vinyl pyrrolidone. Suitable conventional vinyl monomers include the alkyl vinyl ethers, e.g., methyl vinyl ether, ethyl vinyl ether, octyl vinyl ether, etc.; acrylic and methacrylic acid and esters thereof, e.g., methacrylate, methyl methacrylate, etc.; vinyl aromatic monomers, e.g., styrene, α-methyl styrene, etc; vinyl acetate; vinyl alcohol; vinylidene chloride; acrylonitrile and substituted derivatives thereof; methacrylonitrile and substituted derivatives thereof; acrylamide and methacrylamide and N-substituted derivatives thereof; vinyl chloride, crotonic acid and esters thereof; etc.
Suitable polyvinylpyrrolidone copolymers include vinylpyrrolidone / dimethylaminoethylmethacrylate (VP/DMAEMA) copolymers having the formula:
wherein x and y have values selected such that the total molecular weight is 50,000 to 5,000,000 Da, preferably 100,000 Da to 2,500,000Da, more preferably from 500,000 to 1,500,000 Da.
The copolymers of use in the compositions of the present invention are generally provided as a technical grade mixture which includes the polymer dispersed in an aqueous or aqueous/alcoholic carrier and are available in a variety of molecular weights from Ashland Inc. Suitable polymers are available commercially, including from Ashland Inc. under the tradenames Sorez™ HS-205, copolymer 845, copolymer 937, copolymer 958.

Nonionic surfactant

Nonionic surfactants have been found to be particularly effective in combination with the vinylpyrrolidone copolymer for providing improved shine to metal surfaces, in comparison to anionic surfactants, amphoteric surfactants, and the like. As such, the compositions of the present invention comprise a nonionic surfactant, or a mixture thereof. This class of surfactants may be desired as it further contributes to cleaning performance of the hard surface cleaning compositions herein. It has been found in particular that nonionic surfactants strongly contribute in achieving highly improved performance on greasy soap scum removal.
The compositions according to the present invention may comprise up to 15% by weight of the total composition of a nonionic surfactant or a mixture thereof, preferably from 0.1% to 10%, more preferably from 0.5% to 5%, even more preferably from 1.0% to 3% by weight of the total composition.
Suitable nonionic surfactants for use herein are alkoxylated alcohol nonionic surfactants, which can be readily made by condensation processes which are well-known in the art. However, a great variety of such alkoxylated alcohols, especially ethoxylated and/or propoxylated alcohols, are conveniently commercially available. Surfactants catalogs are available which list a number of surfactants, including nonionics.
Preferred alkoxylated alcohols are nonionic surfactants according to the formula RO(E)e(P)pH where R is a hydrocarbon chain of from 2 to 24 carbon atoms, E is ethylene oxide and P is propylene oxide, and e and p which represent the average degree of, respectively ethoxylation and propoxylation, are of from 0 to 24 (with the sum of e + p being at least 1). Preferably, the hydrophobic moiety of the nonionic compound can be a primary or secondary, straight or branched alcohol having from 8 to 24 carbon atoms.
Preferred nonionic surfactants for use in the compositions according to the invention are the condensation product of ethylene and/or propylene oxide with an alcohol having a straight alkyl chain comprising from 6 to 22 carbon atoms, wherein the degree of ethoxylation/propoxylation is from 1 to 15, preferably from 5 to 12 or mixtures thereof. Such suitable nonionic surfactants are commercially available from Shell, for instance, under the trade name Neodol® or from BASF under the trade name Lutensol®, and from Sasol under the tradename Marilpal®.

The organic acid system

The liquid compositions of the present invention are acidic. Therefore they have a pH of from 1.5 to less than 7. Certain lesser grade chrome finishing and stainless steels can be prone to pitting in highly acidic conditions. As such, the composition preferably has a pH of from 1.8 to 6, preferably 2.0 to 2.5, even more preferably 2.1 to 2.4, measured at 25°C.
The composition comprises an organic acid system, for improved safety on such chromed surfaces and stainless steel surfaces. Typically, the acid system comprises any organic acid well-known to those skilled in the art, or a mixture thereof. In preferred embodiments, the organic acid system comprises acids selected from the group consisting of: citric acid, formic acid, acetic acid, maleic acid, lactic acid, glycolic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, methansulphonic acid, and mixtures thereof, more preferably citric acid, formic acid, acetic acid, and mixtures thereof.
The composition preferably comprises the acid system at a level of from 0.01 % to 15%, preferably from 0.5% to 10%, more preferably from 2% to 8%, most preferably from 4% to 7.5% by weight of the total composition.
Formic acid has been found to provide excellent limescale removal performance, in combination with improved surface safety, especially for surfaces which are prone to corrosion. For improved surface safety, especially of more delicate surfaces, the composition preferably comprises formic acid as part of the acid system. In order to achieve the desired pH, the compositions of the present invention may comprise from 0.01% to 15%, preferably from 0.5% to 10%, more preferably from 1% to 8%, even more preferably from 1% to 6%, still more preferably 1% to 4%, yet more preferably 1% to 3%, yet still more preferably 2% to 3% by weight of the total composition of formic acid.
Lactic acid can be used as part of the acid system, especially where antimicrobial or disinfecting benefits are desired. Such compositions may comprise up to 10% by weight of the total composition of lactic acid, preferably from 0.1% to 6%, more preferably from 0.2% to 4%, even more preferably from 0.2% to 3%, and most preferably from 0.5% to 2%.
The compositions of the present invention may comprise from 0.1 to 30%, preferably from 2% to 20%, more preferably from 3% to 15%, most preferably from 3% to 10% by weight of the total composition of acetic acid. In an alternative embodiment herein, the compositions of the present invention may comprise from 0.1 to 5%, preferably from 0.1% to 3%, more preferably from 0.1% to 2%, most preferably from 0.5% to 2% by weight of the total composition of acetic acid. The compositions of the present invention may comprise from 0.1 to 30%, preferably from 1% to 20%, more preferably from 1.5% to 15%, most preferably from 1.5% to 10% by weight of the total composition of citric acid.
The compositions herein can comprise an alkaline material. The alkaline material may be present to trim the pH and/or maintain the pH of the compositions according to the present invention. Examples of alkaline material are sodium hydroxide, potassium hydroxide and/or lithium hydroxide, and/or the alkali metal oxides such, as sodium and/or potassium oxide or mixtures thereof and/or monoethanolamine and/or triethanolamine. Other suitable bases include ammonia, ammonium carbonate, choline base, etc. Preferably, source of alkalinity is sodium hydroxide or potassium hydroxide, preferably sodium hydroxide.
Typically the amount of alkaline material is of from 0.001 % to 20 % by weight, preferably from 0.01 % to 10 % and more preferably from 0.05 % to 3 % by weight of the composition.
Despite the presence of alkaline material, if any, the compositions herein would remain acidic compositions.

Optional ingredients

The compositions according to the present invention may comprise a variety of optional ingredients depending on the technical benefit aimed for and the surface treated.
Suitable optional ingredients for use herein include other acids, chelating agents, nonionic surfactants, vinylpyrrolidone homopolymer, polysaccharide polymer, radical scavengers, perfumes, solvents, other surfactants, builders, buffers, bactericides, hydrotropes, colorants, stabilizers, bleaches, bleach activators, suds controlling agents like fatty acids, enzymes, soil suspenders, brighteners, anti dusting agents, dispersants, pigments, and dyes.

Other acids:

Suitable other acids include inorganic acids, such as hydrochloric acid, sulphurinc acid, sulphamic acid, and the like.

Thickener:

Preferred thickeners are anionic polymeric thickener, more preferably xanthan gum. Surprisingly, anionic polymeric thickeners can be used to achieve the desired composition viscosity, even though the copolymers comprise cationic monomeric units (monomer B).
Preferred anionic polymeric thickeners are polysaccharide polymers. As such, the compositions of the present invention may optionally comprise a polysaccharide polymer or a mixture thereof.
Typically, the compositions of the present invention may comprise from 0.01% to 5% by weight of the total composition of a polysaccharide polymer or a mixture thereof, more preferably from 0.05% to 3% and most preferably from 0.05 % to 1%.
Suitable polysaccharide polymers for use herein include substituted cellulose materials like carboxymethylcellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxymethyl cellulose, succinoglycan and naturally occurring polysaccharide polymers like Xanthan gum, gellan gum, guar gum, locust bean gum, tragacanth gum or derivatives thereof, or mixtures thereof.
In a preferred embodiment according to the present invention the compositions of the present invention comprise a polysaccharide polymer selected from the group consisting of: carboxymethylcellulose, ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, hydroxymethyl cellulose, succinoglycan gum, xanthan gum, gellan gum, guar gum, locust bean gum, tragacanth gum, derivatives of the aforementioned, and mixtures thereof. Preferably, the compositions herein comprise a polysaccharide polymer selected from the group consisting of : succinoglycan gum, xanthan gum, gellan gum, guar gum, locust bean gum, tragacanth gum, derivatives of the aforementioned, and mixtures thereof. More preferably, the compositions herein comprise a polysaccharide polymer selected from the group consisting of: xanthan gum, gellan gum, guar gum, derivatives of the aforementioned, and mixtures thereof. Most preferably, the compositions herein comprise xanthan gum, derivatives thereof, and mixtures thereof. Particularly polysaccharide polymers for use herein are xanthan gum and derivatives thereof. Xanthan gum and derivatives thereof may be commercially available for instance from CP Kelco under the trade name Keltrol RD®, Kelzan S® or Kelzan T®. Other suitable xanthan gums are commercially available by Rhodia under the trade name Rhodopol T® and Rhodigel X747®. Succinoglycan gum for use herein is commercially available by Rhodia under the trade name Rheozan®.
The composition of the invention may comprise additional cleaning ingredients.

Other polymers

In order to provide improved shine over a wider range of surfaces, the compositions of the present invention may comprise a vinylpyrrolidone homopolymer or other polymer, or a mixture thereof. Typically, the compositions of the present invention may comprise from 0.01% to 5% by weight of the total composition of a vinylpyrrolidone homopolymer or other polymer, or a mixture thereof, more preferably from 0.01% to 3% and most preferably from 0.02% to 0.5%.
Suitable vinylpyrrolidone homopolymers for use herein are homopolymers of N-vinylpyrrolidone having the following repeating monomer:
wherein n (degree of polymerisation) is an integer of from 10 to 1,000,000, preferably from 20 to 100,000, and more preferably from 20 to 10,000.
Accordingly, suitable vinylpyrrolidone homopolymers ("PVP") for use herein have an average molecular weight of from 1,000 to 100,000,000, preferably from 2,000 to 10,000,000, more preferably from 5,000 to 1,000,000, and most preferably from 50,000 to 500,000.
Suitable vinylpyrrolidone homopolymers are commercially available from ISP Corporation, New York, NY and Montreal, Canada under the product names PVP K-15® (viscosity molecular weight of 10,000), PVP K-30® (average molecular weight of 40,000), PVP K-60® (average molecular weight of 160,000), and PVP K-90® (average molecular weight of 360,000). Other suitable vinylpyrrolidone homopolymers which are commercially available from BASF Cooperation include Sokalan HP 165®, Sokalan HP 12®, Luviskol K30®, Luviskol K60®, Luviskol K80®, Luviskol K90®; vinylpyrrolidone homopolymers known to persons skilled in the detergent field (see for example EP-A-262,897 and EP-A-256,696 ).
According to a very preferred execution of the present invention, vinylpyrrolidone homopolymers are advantageously selected.

Chelating agent

The compositions of the present invention may comprise a chelating agent or mixtures thereof, as a preferred optional ingredient. Chelating agents can be incorporated in the compositions herein in amounts ranging up to 10% by weight of the total composition, preferably 0.01% to 5.0%, more preferably 0.05% to 1%.
Suitable phosphonate chelating agents to be used herein may include alkali metal ethane 1-hydroxy diphosphonates (HEDP), alkylene poly (alkylene phosphonate), as well as amino phosphonate compounds, including amino aminotri(methylene phosphonic acid) (ATMP), nitrilo trimethylene phosphonates (NTP), ethylene diamine tetra methylene phosphonates, and diethylene triamine penta methylene phosphonates (DTPMP). The phosphonate compounds may be present either in their acid form or as salts of different cations on some or all of their acid functionalities.
Preferred chelating agents to be used herein are diethylene triamine penta methylene phosphonate (DTPMP) and ethane 1-hydroxy diphosphonate (HEDP). In a particularly preferred execution of the present invention, the chelating agent is selected to be ethane 1-hydroxy diphosphonate (HEDP). Such phosphonate chelating agents are commercially available from Monsanto under the trade name DEQUEST®.
Polyfunctionally-substituted aromatic chelating agents may also be useful in the compositions herein. See U.S. patent 3,812,044, issued May 21, 1974, to Connor et al. Preferred compounds of this type in acid form are dihydroxydisulfobenzenes such as 1,2-dihydroxy -3,5-disulfobenzene. A preferred biodegradable chelating agent for use herein is ethylene diamine N,N'- disuccinic acid, or alkali metal, or alkaline earth, ammonium or substitutes ammonium salts thereof or mixtures thereof. Ethylenediamine N,N'- disuccinic acids, especially the (S,S) isomer have been extensively described in US patent 4, 704, 233, November 3, 1987, to Hartman and Perkins . Ethylenediamine N,N'- disuccinic acids is, for instance, commercially available under the tradename ssEDDS® from Palmer Research Laboratories.
Suitable amino carboxylates to be used herein include tetra sodium glutamate diacetate (GLDA), ethylene diamine tetra acetates, diethylene triamine pentaacetates, diethylene triamine pentaacetate (DTPA), N- hydroxyethylethylenediamine triacetates, nitrilotri-acetates, ethylenediamine tetrapropionates, triethylenetetraaminehexa-acetates, ethanol-diglycines, propylene diamine tetracetic acid (PDTA) and methyl glycine di-acetic acid (MGDA), both in their acid form, or in their alkali metal, ammonium, and substituted ammonium salt forms. Particularly suitable amino carboxylates to be used herein are diethylene triamine penta acetic acid, propylene diamine tetracetic acid (PDTA) which is, for instance, commercially available from BASF under the trade name Trilon FS® methyl glycine di-acetic acid (MGDA), tetra sodium glutamate diacetate (GLDA) which is, for instance, commercially available from AkzoNobel under the trade name Dissolvine® GL.
Further carboxylate chelating agents to be used herein include salicylic acid, aspartic acid, glutamic acid, glycine, malonic acid or mixtures thereof.

Solvent

The compositions of the present invention may further comprise a solvent or a mixture thereof, as an optional ingredient. Solvents to be used herein include all those known to those skilled in the art of hard-surfaces cleaner compositions. In a highly preferred embodiment, the compositions herein comprise an alkoxylated glycol ether (such as n-Butoxy Propoxy Propanol (n-BPP)) or a mixture thereof.
Typically, the compositions of the present invention may comprise from 0.1% to 5% by weight of the total composition of a solvent or mixtures thereof, preferably from 0.5% to 5% by weight of the total composition and more preferably from 1% to 3% by weight of the total composition.

Additional surfactant

The compositions of the present invention may comprise an additional surfactant, or mixtures thereof, on top of the nonionic surfactant already described herein. Additional surfactants may be desired herein as they further contribute to the cleaning performance and/or shine benefit of the compositions of the present invention. Surfactants to be used herein include anionic surfactants, cationic surfactants, amphoteric surfactants, zwitterionic surfactants, and mixtures thereof. Accordingly, the compositions according to the present invention may comprise up to 15% by weight of the total composition of another surfactant or a mixture thereof, on top of the nonionic surfactant already described herein.
In preferred embodiments, the composition comprises limited amounts, or no anionic surfactant. As such, the hard surface composition can comprise less than 2wt%, preferably less than 1wt%, more preferably less than 0.5wt%, most preferably less than 0.1 wt% of anionic surfactant. Suitable anionic surfactants include alkyl sulphonates, alkyl aryl sulphonates, or mixtures thereof.
If used, suitable linear alkyl sulphonates include C8 sulphonate like Witconate® NAS 8 commercially available from Witco.
Suitable zwitterionic surfactants for use herein contain both basic and acidic groups which form an inner salt giving both cationic and anionic hydrophilic groups on the same molecule at a relatively wide range of pH's. The typical cationic group is a quaternary ammonium group, although other positively charged groups like phosphonium, imidazolium and sulfonium groups can be used. The typical anionic hydrophilic groups are carboxylates and sulfonates, although other groups like sulfates, phosphonates, and the like can be used.
Some common examples of zwitterionic surfactants (i.e. betaine/sulphobetaine) are described in U.S. Pat. Nos. 2,082,275 , 2,702,279 and 2,255,082 .
For example Coconut dimethyl betaine is commercially available from Seppic under the trade name of Amonyl 265®. Lauryl betaine is commercially available from Albright & Wilson under the trade name Empigen BB/L®. A further example of betaine is Lauryl-immino-dipropionate commercially available from Rhodia under the trade name Mirataine H2C-HA®.
Particularly preferred zwitterionic surfactants for use in the compositions of the present invention are the sulfobetaine surfactants as they deliver optimum soap scum cleaning benefits.
Examples of particularly suitable sulfobetaine surfactants include tallow bis(hydroxyethyl) sulphobetaine, cocoamido propyl hydroxy sulphobetaines which are commercially available from Rhodia and Witco, under the trade name of Mirataine CBS® and Rewoteric AM CAS 15® respectively.
Amphoteric and ampholytic detergents which can be either cationic or anionic depending upon the pH of the system are represented by detergents such as dodecylbeta-alanine, N-alkyltaurines such as the one prepared by reacting dodecylamine with sodium isethionate according to the teaching of U.S. Pat. No. 2,658,072 , N-higher alkylaspartic acids such as those produced according to the teaching of U.S. Pat. No. 2,438,091 , and the products sold under the trade name "Miranol", and described in U.S. Pat. No. 2,528,378 . Additional synthetic detergents and listings of their commercial sources can be found in McCutcheon's Detergents and Emulsifiers, North American Ed. 1980.
Suitable amphoteric surfactants include the amine oxides. Examples of amine oxides for use herein are for instance coconut dimethyl amine oxides, C12-C16 dimethyl amine oxides. Said amine oxides may be commercially available from Clariant, Stepan, and AKZO (under the trade name Aromox®). Other suitable amphoteric surfactants for the purpose of the invention are the phosphine or sulfoxide surfactants.
Cationic surfactants suitable for use in compositions of the present invention are those having a long-chain hydrocarbyl group. Examples of such cationic surfactants include the quaternary ammonium surfactants such as alkyldimethylammonium halogenides. Other cationic surfactants useful herein are also described in U.S. Patent 4,228,044, Cambre, issued October 14, 1980 .

The process of cleaning a hard-surface or an object

The copolymers, described herein, can be used in an acidic composition for removing limescale and/or improving shine on chromed surfaces and stainless steel surfaces.
Therefore, the present invention further encompasses a process of cleaning a hard surface or an object, preferably removing limescale and/or improving shine on said chromed surface or stainless steel surface.
The objects having a stainless steel surface or a chromed surface may be water-taps or parts thereof, shower heads, other chromed or stainless steel bathroom fittings, water-valves, metal objects, objects made of stainless-steel, cutlery and the like.
The preferred process of cleaning a hard-surface or an object (preferably removing limescale from said hard-surface or said object) comprises the step of applying a composition according to the present invention onto said chromed surface or stainless steel surface, leaving said composition on said surface, preferably for an effective amount of time, more preferably for a period comprised between 10 seconds and 10 minutes, most preferably for a period comprised between 15 seconds and 4 minutes; optionally wiping said hard-surface or object with an appropriate instrument, e.g. a sponge; and then preferably rinsing said surface with water.
Even though said chromed or stainless steel surface may optionally be wiped and/or agitated during the process herein, it has been surprisingly found that the process of the present invention allows good limescale removal performance without any additional mechanical wiping and/or agitation action. The lack of need for additional wiping and/or mechanical; agitation provides an added convenience for the user of the compositions herein.
The compositions of the present invention may be contacted to the surface to be treated in its neat form or in its diluted form. Preferably, the composition is applied in its neat form.
The compositions according to the present invention are particularly suitable for treating hard-surfaces located in and around the house, such as in bathrooms, toilets, garages, on driveways, basements, gardens, kitchens, etc., and preferably in bathrooms. It is however known that such surfaces (especially bathroom surfaces) may be soiled by the so-called "limescale-containing soils". By "limescale-containing soils" it is meant herein any soil which contains not only limescale mineral deposits, such as calcium and/or magnesium carbonate, but also soap scum (e.g., calcium stearate) and other grease (e.g. body grease). By "limescale deposits" it is mean herein any pure limescale soil, i.e., any soil or stains composed essentially of mineral deposits, such as calcium and/or magnesium carbonate.
The compositions herein may be packaged in any suitable container, such as bottles, preferably plastic bottles, optionally equipped with an electrical or manual trigger spray-head.

METHODS

A) pH measurement:

The pH is measured on the neat composition, at 25°C, using a Sartarius PT-10P pH meter with gel-filled probe (such as the Toledo probe, part number 52 000 100), calibrated according to the instructions manual.

B) Shine:

Stainless steel tiles (Inox 304L grade, bright annealed (BA) finish), 20 cm x 20 cm, supplied by LASERTEK N.V. (Jubellaan 76B, 2800 Mechelen) were prepared using the following procedure:

Clean tiles were prepared by washing using a nil-polymer hard-surface cleaner and rinsing with tap water having a water hardness of 15 grains per gallon (257 ppm) until free of residue, before drying using paper towels. The tiles were then cleaned using isopropanol alcohol to remove any remaining residue.

The following test procedure was used, using two replicates for each test composition:

3.0 ml of test composition was applied to the top of the tile, starting from the left to the right corner, with a pipette before being spread uniformly using a wet sponge, with four vertical strokes followed and four horizontal strokes, such that the entire tile is contacted with the test product. The treated tiles were then left for 15 seconds.

The tiles were inclined against a wall at a near vertical angle, then rinsed uniformly for 30 seconds using a shower head connected to a tap with a water flow rate of 4L/minute. The tiles were then left to dry in a controlled temperature and humidity room at 20°C and a relative humidity of 40%.
The tiles were visually graded by three panelists to assess the shine (level of watermarks and gloss) after the aforementioned application procedure.
The grading was done using clean tiles as reference. In the visual grading, the following scale was used:

0 = No difference exists
1 = Maybe there is a difference, but I am not sure
2 = I am sure there is a difference, but it is small
3 = There is a significant difference
4 = There is a huge difference,

The tiles were rinsed again, using the same procedure as above, and regraded to give the relative shine after one rinse cycle. The tiles were then rinsed again twice, using the same procedure and regraded to give the relative shine after three rinse cycles.

EXAMPLES

These following compositions were made comprising the listed ingredients in the listed proportions (active weight %). Example 1 is a composition of the present invention, while example A is a comparative composition which comprised polyvinylpyrrolidone homopolymer instead of the copolymer.

The relative shine benefit was assessed using the procedure described earlier.

Composition	Ex 1 of invention	Ex A Comparative
	wt%	wt%
Citric acid	1.7	1.7
Formic acid	2.7	2.7
C9-C11 8EO¹	2.2	2.2
Sodium Hydroxide	0.15	0.15
Xantham gum	0.15	0.15
Perfume	0.2	0.2
dyes	0.008	0.008
Polyvinylpyrrolidone (PVP)²	-	0.025
PVP Copolymer³	0.025	-
Water	Balance up to 100	Balance up to 100
pH	2.2	2.2

Shine (visual grading):
after application	-0.6	-3.5
after 1 cycle	-1.1	-2.8
after 3 cycles	-1.8	-3.2

1 Nonionic surfactant, sourced as Neodol® 91-8 from Shell.
2 Polyvinylpyrrolidone, sourced as PVP K-60 from Ashland Inc.
3 vinylpyrrolidone/dimethylaminoethylmethacrylate (VP/DMAEMA) copolymer, sourced as Sorez™ HS-205 from Ashland Inc.

Since the gradings were done using a clean slide as reference, all gradings were negative, with a smaller negative grading meaning less shine loss after each rinse cycle. As can be seen from the test results, the composition comprising the polyvinylpyrrolidone copolymer provides improved shine in comparison to equivalent compositions comprising the polyvinylpyrrolidone homopolymer.

Examples 2 to 10 are further examples of compositions of the present invention.

Examples:	2	3	4	5	6	7	8	9	10
Acids
Formic acid	4.0	2.0	1.8	1.8	2.5	2.0	2.0	2.0	4.0
Acetic acid	-	3.5	8.0	8.0	5.5	6.0	5.0	-	-
Citric acid	-	-	-	-	-	-	-	8.0	2.0
Lactic acid	-	-	-	1.0	2.0	-	1.0	-	1.5

Surfactants
Neodol 91-8®	2.0	4.0	2.2	5.0	3.0	5.0	2.5	2.0	1.8

Polymers:
Kelzan T	0.25	0.25	0.25	0.25	0.25	0.10	0.30	0.20	0.25
vinylpyrrolidone copolymer³	0.025	0.1	0.05	0.1	0.04	0.1	0.03	0.04	0.025

Solvent:
n-BPP	1.0	-	-	-	2.0	-	-	-	-

Minors: (preservative, dve. perfume, and the like)
	0.10	0.50	0.25	0.55	0.10	0.50	0.3	0.20	0.3

Alkaline Material:
KOH - to pH :	2.3	-	2.9	2.8	2.8	-	-	-	-
NaOH - to pH :	-	2.2	-	-	-	2.5	2.3	2.0	2.2
Water:	----- to 100% -----

Formic acid, lactic acid and acetic acid are commercially available from Aldrich.
Neodol 91-8® is a C₉-C₁₁ EO8 nonionic surfactant, commercially available from SHELL.
Sulphated Safol 23® is a branched C_12-13 sulphate surfactant based on Safol 23 an alcohol commercially available from Sasol, which has been sulphated.

n-BPP is n-butoxy propoxy propanol.
Kelzan T^® is a Xanthan gum supplied by Kelco.
PVP is a vinylpyrrolidone homopolymer, commercially available from ISP Corporation
BHT is Butylated Hydroxy Toluene

The dimensions and values disclosed herein are not to be understood as being strictly limited to the exact numerical values recited. Instead, unless otherwise specified, each such dimension is intended to mean both the recited value and a functionally equivalent range surrounding that value. For example, a dimension disclosed as "40 mm" is intended to mean "about 40 mm."

Claims

A liquid acidic hard surface cleaning composition having a pH of from 1.5 to less than 7, and comprising:
a. a vinylpyrrolidone copolymer, wherein the vinylpyrrolidone copolymer has the following structure:
wherein:
x is from 20 to 99 mol%, preferably from 40 to 99 mol%,

y is from 1 to 80 mol%, preferably from 1 to 40 mol%,

z is from 0 to 50 mol%, preferably 0 mol%,

such that (x+y+z) = 100,

R₁ is H or CH₃,

Z is O or NH,

R₂ is C_aH_2a, wherein a is from 1 to 4

R3 is independently C1 to C4 alkyl, and

M is a vinyl or vinylidene monomer, preferably copolymerisable with vinyl pyrrolidone other than the monomer identified in [ ]_y,

b. nonionic surfactant; and

c. an organic acid system.
The hard surface cleaning composition according to claim 1, wherein the composition comprises vinylpyrrolidone copolymer at a level of from 0.001% to 2.0%, more preferably from 0.01% to 1.0%, yet more preferably from 0.02% to 0.10%, most preferably from 0.025 to 0.05% by weight of the cleaning composition, of the copolymer.
The composition according to any of the preceding claims, wherein said composition has a pH of from 1.8 to 6, preferably 2.0 to 2.5, even more preferably 2.1 to 2.4, measured at 25°C.
The composition according to any of the preceding claims, wherein the organic acid is selected from the group consisting of: citric acid, formic acid, acetic acid, maleic acid, lactic acid, glycolic acid, oxalic acid, succinic acid, glutaric acid, adipic acid, methansulphonic acid, and mixtures thereof.
The composition according to claim 4, wherein the acid system comprises acid selected from the group consisting of: citric acid, formic acid, acetic acid, and mixtures thereof.
The composition according to any preceding claims, wherein said composition comprises the acid system at a level of from 0.01 % to 15%, preferably from 0.5% to 10%, more preferably from 2% to 8%, most preferably from 4% to 7.5% by weight of the total composition.
The composition according to any of the preceding claims, wherein the nonionic surfactant is the condensation product of ethylene and/or propylene oxide with an alcohol having a straight alkyl chain comprising from 6 to 22 carbon atoms, wherein the degree of ethoxylation/propoxylation is from 1 to 15, preferably from 5 to 12 or mixtures thereof.
The composition according to any preceding claim, wherein the nonionic surfactant is present at a level of from 0.1 to 10%, preferably from 0.5 to 5%, more preferably from 1.0 to 3% by weight of the composition.
The composition according to any preceding claim, organic acid to vinylpyrrolidone copolymer is from 50:1 to 500:1, preferably from 100:1 to 350:1, more preferably from 250:1 to 300:1.
The composition according to any preceding claim, wherein the weight ratio of nonionic surfactant to vinylpyrrolidone copolymer is from 20 to 200, preferably from 40 to 150, more preferably from 50:1 to 100:1.
The composition according to any of the preceding claims, wherein said composition comprises less than 2wt%, preferably less than 1wt%, more preferably less than 0.5wt%, most preferably less than 0.1 wt% of anionic surfactant.
The composition according to any of the preceding claims, wherein said composition further comprises a thickener, preferably an anionic polymeric thickener, more preferably xanthan gum.
The use of a hard surface composition comprising a copolymer of vinylpyrrolidone, for providing improved shine to a chromed surface or stainless steel surface, wherein the vinylpyrrolidone copolymer has the following structure:
wherein:
x is from 20 to 99 mol%, preferably from 40 to 99 mol%;

y is from 1 to 80 mol%, preferably from 1 to 40 mol%;

z is from 0 to 50 mol%, preferably 0 mol%;

such that (x+y+z) = 100;

R₁ is H or CH₃;

Z is O or NH;

R₂ is C_aH_2a, wherein a is from 1 to 4;

R3 is independently C1 to C4 alkyl; and

M is a vinyl or vinylidene monomer, preferably copolymerisable with vinyl pyrrolidone other than the monomer identified in [ ]_y.