WO2017174959A1

WO2017174959A1 - Sprayable thickened aqueous acidic compositions

Info

Publication number: WO2017174959A1
Application number: PCT/GB2017/050802
Authority: WO
Inventors: Jospeh CONVERY
Original assignee: Reckitt Benckiser Llc; Reckitt Benckiser (Brands) Limited
Priority date: 2016-04-08
Filing date: 2017-03-22
Publication date: 2017-10-12

Abstract

A sprayable thickened aqueous composition for use as an acidic hard surface cleaning and disinfecting composition, comprises: i.a zwitterionicor betaine surfactant; ii.an acid (preferably a water-soluble organic acid selected from lactic acid; glycolic acid and citric acid); iii.an alcohol, diol, glycol, ether or polyurethane based thickener; iv.optionally an anionic and / or non-ionic surfactant; v.a thickener; vi.optionally, but desirably, one or more conventional additives; and vii.water.

Description

SPRAYABLE THICKENED AQUEOUS ACIDIC COMPOSITIONS

The present invention relates to thickened cleaning and disinfecting compositions which are acidic in nature and which exhibit good cleaning, disinfecting and long-term stability.

While the prior art has provided various compositions directed to cleaning and disinfecting hard surfaces, particularly lavatory surfaces, there is a continuing need in the art for vertical surface clinging cleaner compositions which provide satisfactory cleaning, especially of limescale deposits from metal, enamel and porcelain surfaces (such as found on lavatory fixtures), disinfection of hard surfaces and good long-term stability of the thickened compositions.

According to a first aspect of the invention there is provided a sprayable thickened aqueous composition for use as an acidic hard surface cleaning and disinfecting composition, comprising: i. a zwitterionic or betaine surfactant;

ii. an acid (preferably a water-soluble organic acid selected from lactic acid;

glycolic acid and citric acid);

iii. an alcohol, diol, glycol, ether or polyurethane based thickener;

iv. optionally an anionic and / or non-ionic surfactant;

v. a thickener;

vi. optionally, but desirably, one or more conventional additives; and

vii. water.

It has been found that the composition of the invention displays excellent properties. Firstly the composition achieves superb disinfection. The compositions of the invention are preferably effective against both gram positive and gram negative bacteria.

Without wishing to be bound by theory it is postulated that this effect is derived from a preferred method of application (a spray). It is reasoned that when the composition is pressurized in a spray, the gel is disrupted and the active(s) is liberated to effect superior disinfection.

Secondly the composition achieves superb cleaning, particularly soap scum removal.

More importantly the composition has been found to show beneficial clinging properties to surfaces being addressed. This has been found to be especially applicable for vertical surfaces. Surprisingly this beneficial clinging has been found to be possible without problems of application. Indeed in this regard it has been found that the composition displays a low moving viscosity: the composition provides exceptional shear thinning, together with a surprisingly relatively medium-high resting viscosity. The sheared viscosity is so low that may be applied to a surface using a conventional spray applicator such as a trigger spray.

Further it has been observed that the composition displays a motility after application using a spray. The composition of the invention exhibits some degree of motility, e.g., self-induced movement when the composition is applied as a film or laminar layer onto a hard surface at normal atmospheric conditions ('sea level') and at ambient temperature (approx. 20 degrees centigrade). It is hypothesized that the composition may move between a surface and a soil deposit (e.g. soap scum), "lifting" the latter which both removes the soils off the hard surface, and at the same time supplying a fresh quantity of the composition to the locus of the stain or soil and thus continue its removal from the hard surface. This effect is believed to be possibly due to surface tension gradients, perhaps allied to crossing of phase boundaries, when volatile compounds evaporate in the composition evaporate from the hard surface on which it has been applied. Surprisingly however, when the composition is in a bulk form, e.g., in a larger three dimensional volume such as when contained in a container or in a vessel, and wherein the ratio of surface area to volume of the liquid composition is substantially reduced as compared to the ratio of surface area to volume of the liquid when the liquid composition is in the form of a lamina or layer formed on a hard surface, no visible "twitching" or movement, is observed in the bulk form. According to a second aspect of the invention there is provided a process for cleaning limescale from a hard surface comprising the process step of contacting the hard surface having limescale thereon with a cleaning effective amount of the composition according to the first aspect of the invention.

Preferably the hard surface to be cleaned comprises a vertical hard surface. In this case it has been found that the composition / process of the inventive displays superior cleaning power.

Here is it postulated that the vertical clean is superior due to the flow characteristics of the composition. The composition has been found to flow slowly down the vertical surface of the tile. As this occurs it is believed that the applied composition "rotates" and presents a new cleaning surface composition as it is slowly flows down the tile. Most preferably the process involves a spray applicator. The spray applicator may be in pressurised (permanently or pre- pressurised) form such as an aerosol spray. The spray applicator may be manually operated, e.g. using a "trigger" sprayer or comprise a reservoir that is manually pressurised by a user following discharge through a dispensing head.

In a preferred embodiment of the invention, there is provided a method for cleaning (especially for the removal of limescale deposits) and disinfecting metal, enamel and porcelain surfaces such as are found on lavatory fixtures.

The composition also necessarily comprises 0.1 - 7 percent wt. of a betaine surfactant which is, preferably selected from water dispersible and water soluble betaine surfactants. Exemplary betaine surfactants include those which may be represented by the general formula:

wherein Ri is an alkyl group containing from 8 to 18 carbon atoms, or the amido radical which may be represented by the following general formula :

wherein R is an alkyl group having from 8 to 18 ca rbon atoms, a is an integer having a va lue of from 1 to 4 inclusive, and R₂ is a Ci-C4 alkylene group. Examples of such water-soluble betaine surfactants include dodecyl dimethylbetaine, cocoamidopropyl betaine as well as cocoamidopropyl dimethyl betaine, the latter of which is particularly preferred. I n certain preferred embodiments, cocoamidopropyl dimethyl betaine is particularly preferred and in specific especially preferred embodiments is the sole betaine surfactant present in the inventive compositions.

Generally the non-ionic surfactant is present in not more than about 10% wt. based on the total weight of the composition of which it forms a part. Desirably the non-ionic surfactant is present in an amount of from 0.01 to 5% wt., and more desirably from 0.01 to 2% wt.

Further examples of useful non-ionic surfactants are one or more amine oxides. Exemplary amine oxides include:

A) Alkyl di (lower alkyl) amine oxides in which the alkyl group has about 10-20, and preferably 12-16 carbon atoms, and can be straight or branched chain, saturated or unsaturated. The lower alkyl groups include between 1 and 7 carbon atoms. Examples include lauryl dimethyl amine oxide, myristyl dimethyl amine oxide, and those in which the alkyl group is a mixture of different amine oxide, dimethyl cocoamine oxide, dimethyl (hydrogenated tallow) amine oxide, and myristyl/palmityl dimethyl amine oxide;

B) Alkyl di (hydroxy lower alkyl) amine oxides in which the a lkyl group has about 10-20, and preferably 12-16 carbon atoms, and ca n be straight or branched chain, saturated or unsaturated. Examples are bis(2 -hydroxy ethyl) cocoamine oxide, bis(2-hydroxyethyl) tallowamine oxide; and bis(2-hydroxyethyl) stearylamine oxide;

C) Alkylamidopropyl di(lower alkyl) amine oxides in which the alkyl group has about 10-20, and preferably 12-16 carbon atoms, and ca n be straight or branched chain, saturated or unsaturated. Examples are cocoamidopropyl dimethyl amine oxide and tallowamidopropyl dimethyl amine oxide; and D) Alkylmorpholine oxides in which the alkyl group has about 10-20, and preferably 12-16 carbon atoms, and can be straight or branched chain, saturated or unsaturated. Preferably the amine oxide constituent is an alkyl di (lower alkyl) amine oxide as denoted above and which may be represented by the following structure:

wherein each: Ri is a straight chained C1-C4 alkyl group, preferably both Ri are methyl groups; and, R₂ is a straight chained Cs-Cis alkyl group, preferably is C10-C14 alkyl group, most preferably is a C12 alkyl group.

Each of the alkyl groups may be linear or branched, but most preferably are linear.

Technica l grade mixtures of two or more amine oxides may be used, wherein amine oxides of varying chains of the R₂ group are present. Preferably, the amine oxides used in the present invention include R₂ groups which comprise at least 50 percent wt., preferably at least 60 percent wt. of C12 alkyl groups and at least 25 percent wt. of C14 alkyl groups, with not more than 15 percent wt. of Ci6, Cis or higher alkyl groups as the R₂ group.

Exemplary useful non-ionic surfactants include condensation products of alkylene oxide groups with an organic hydrophobic compound, such as an aliphatic or alkyl aromatic compound.

Further exemplary useful non-ionic surfactants include the polyoxyethylene ethers of alkyl aromatic hydroxy compounds, e. g. alkylated polyoxyethylene phenols, polyoxyethylene ethers of long chain aliphatic alcohols, the polyoxyethylene ethers of hydrophobic propylene oxide polymers, and the higher alkyl amine oxides. Also contemplated as useful are ethoxylated alkyl phenols such as octylphenolethoxylates and nonylphenolethoxylates.

Preferred non-ionic surfactants are ethoxylated alcohols. The com pounds a re well known and may be formed by condensation of an alcohol, or mixtures thereof, with sufficient ethylene oxide to produce a compound having a polyoxyethylene. Preferably, the number of ethylene oxide units present is an amount sufficient to ensure solubility of the compound in an aqueous composition of this invention or in any dilution thereof. Desirably, the ethoxylated alcohols are produced by condensation of about 4 to 20, more preferably 6 to 18, moles of ethylene oxide with 1 mole of the linear primary aliphatic alcohol.

The aliphatic alcohol may be linear or may be branched, and may be a primary, secondary or tertiary C6-C22 alcohol (for example: decyl alcohol, dodecyl alcohol, tridecyl alcohol, hexadecyl alcohol, octadecyl alcohol, and the like). As known to those skilled in the art, the number of moles of ethylene oxide which are condensed with one mole of aliphatic alcohol depends upon the molecular weight of the hydrophobic portion of the condensation product. The aliphatic alcohols are desirably a primary, seconda ry or tertiary aliphatic alcohol having about 10 to 20, and preferably 11 to 17, carbon atoms, and most preferably is a n alcohol having 12 to 16 carbon atoms. Most preferably, the non-ionic surfactant of the present inventive compositions is the condensation product of linear or branched C12-C16 aliphatic alcohols, especially C12-C16 linear aliphatic alcohols or mixtures thereof, with sufficient ethylene oxide to provide an average of from 6 to 12 moles of ethylene oxide per molecule. Most preferably, the non-ionic surfactant consists solely of linear or branched C12-C16 aliphatic alcohols with 6 to 9 moles of ethylene oxide per molecule.

Examples of anionic surfactants which may be used in the cleaning composition include but are not limited to: alkali metal salts, ammonium salts, amine salts, aminoalcohol salts or the magnesium salts of one or more of the following compounds: alkyl sulphates, alkyl ether sulphates, alkylamidoether sulphates, alkylaryl polyether sulphates, monoglyceride sulphates, alkylsulphonates, alkylamide sulphonates, alkylarylsulphonates, olefinsulphonates, paraffin sulphonates, alkyl sulphosuccinates, alkyl ether sulphosuccinates, alkylamide sulphosuccinates, alkyl sulphosuccinamate, alkyl sulphoacetates, alkyl phosphates, alkyl ether phosphates, acyl sarconsinates, acyl isothionates and N-acyl taurates. Generally, the alkyl or acyl group in these various compounds comprises a carbon chain containing 12 to 20 carbon atoms.

Other anionic surfactants which may be used include fatty acid salts, including salts of oleic, ricinoleic, palmitic and stearic acids; copra oils or hydrogenated copra oil acid, and acyl lactylates whose acyl group contains 8 to 20 carbon atoms.

An essential feature of the inventive compositions is one or more other water-soluble organic acids. The acid mixture may be present in any effective amount, but desirably is not present in amounts of more than about 10% wt. based on the total weight of the compositions. Preferably the acid mixture is present from 0.01 to 10% wt., more preferably from 0.1 to 10% wt. of the compositions.

The water-soluble organic acids include at least two carbon atoms and include at least one carboxyl group (-COOH) in their structure.

Particularly useful as water-soluble organic acids are acids selected from the group consisting of lactic acid, citric acid and glycolic acid.

This is particularly important as the compositions are acidic in nature.

The inventive compositions are desirably low odour, and are easy to disperse onto surfaces to be cleaned and disinfected.

As noted, the compositions of the invention are thickened and have a viscosity greater than water.

The actual degree of thickening is dependent on the amount of thickener included in a composition. Generally the thickener is present in not more than about 10% wt. based on the total weight of the composition of which it forms a part. Desirably the thickener is present in an amount of from 0.01 to 10% wt., and more desirably from 0.01 to 5% wt.

The thickener may comprise a polyhydric alcohol. Typical polyhydric alcohols include glycerol (also known as glycerin), polya!ky!ene glycols and more preferably alkylene poiyols and their derivatives, including propylene glycol, dipropylene glycol, polypropylene glycol, polyethylene glycol and derivatives thereof, sorbitol, hydroxypropyl sorbitol , hexylene glycol, 1,3 -butylene glycol, 1,2,6- hexanetriol, ethoxylated glycerol, propoxylated glycerol and mixtures thereof.

Polyurethane associative thickeners are well known and described in many publications (such as in U.S. Pat. No. 4,079,028 and U.S. Pat. No. 4,155,892, both assigned to Rohm and Haas).

The composition of the invention may, optionally, further include minor amounts, suitably less than a combined total amount of 10% wt., and more preferably not more than 5% wt., of conventional additives. Examples of suitable conventional additives include but not are limited to: colourants such as dispersible pigments and dyes (including acid dyes); fragrances and perfumes (typically proprietary compositions); pH adjusting agents; non-aqueous solvents (including alcohols, glycols and glycol ethers); perfume carriers; optical brighteners (including those based on stilbene based compounds) and hydrotropes (including urea and alkyl diphen ether disulphonates), as well as other conventional additives.

The compositions of the invention are acidic, and exhibit a pH of less than 7, more preferably about 4.5 and less and most preferably from 2 to 3.5.

Whereas the presence of the acid mixture described above will impart acidity to the composition, it is frequently desirable to include a pH adjusting agent to the compositions to maintain the compositions at approximately a desired pH (or pH range). Exemplary useful pH buffers include inorganic and organic buffering agents, and especially include alkali metal and alkaline earth metal hydroxides such as sodium hydroxide and potassium hydroxide. Particularly preferred is sodium hydroxide which is widely available at low cost, and is effective. Further suitable adjusting agents include phosphorus containing compounds, monovalent and polyvalent salts such as of silicates, carbonates, and borates, certain acids and bases, tartrates and certain acetates. Further exemplary pH adjusting agents include mineral acids, basic compositions, and organic acids, which are typically required in only minor amounts. Further non-limiting exemplary pH buffering compositions include the alkali metal phosphates, polyphophates, pyrophosphates, triphosphates, tetraphosphates, silicates, metasilicates, polysilicates, carbonates, hydroxides, and mixtures of the same. Certain salts, such as the alkaline earth phosphates, carbonates, hydroxides, can also function as buffers. It may also be suitable to use as buffers such materials as aluminosilicates (zeolites), borates, aluminates- ; and their alkali metal salts. Citrates and citric acid may also be advantageously used in the compositions.

Others not described here may also be used.

Such materials as described above are each individually known to the art, and are commercially available. For any particular composition described above, any optional ingredients should be compatible with the other ingredients present.

As is noted above, the compositions according to the invention are aqueous in nature. Water is added to provide to 100% by weight of the compositions of the invention. The water is preferably deionized water. The compositions may be made by simply mixing measured amounts of the individual constituents into water, at room temperature under constant stirring until a homogenous mixture is attained. A preferred preparation method obeys the following addition steps:

1) Thickener

5 2) Surfactant

3) Organic Additives (e.g. Fragrance, Ethers)

4) Water

5) Acids

6) Remaining conventional additives (e.g. salts, dyes) 0 The thickened aqueous acidic hard surface cleaning and disinfecting composition according to the invention is desirably provided as a ready to use product which may be directly applied to a hard surface. The inventive compositions are particularly useful in cleaning and disinfecting lavatory fixtures such as shower stalls, bathtubs and bathing appliances (racks, curtains, shower doors, shower bars) toilets, bidets, wall and flooring surfaces as well as in the cleaning and 5 disinfecting of lavatory fixtures, especially toilets and bidets. The compositions may be packaged in any suitable container particularly flasks or bottles, including squeeze-type bottles, as well as bottles provided with a spray apparatus which is used to dispense the composition by spraying.

The invention will now be exemplified by the following Examples.

Preferred compositions are shown below:

0

Examples

following composition was tested.

Test Methodology

Procedure

Methods and Materials

High-gloss white ceramic tiles, 15 x 15 cm. (white glazed ceramic wall tile, Lasselsberger, a.s. Adelova 2549/1, 320 00 PIzn, Jizni Predmesti, made in Czech

Republic)

Plastic bottle (500 ml.) with screw cap

Calibrated Balance

Ultrasonic Bath

Laboratory Homogenizer

Air Gravity Spray Gun

Convection Oven capable of reaching 180°C

Sponges

Test Soil

Ethanol, 96 MEK denatured

Calcium Stearate, fine

Demineralised water

Soot/Special black 4 (carbon black) Soil Preparation

The test soil is a calcium stearate suspension of the following composition:

85.0% ethanol, 96 MEK denatured

5.0% calcium stearate, fine

9.8% water, demineralized

0.2. soot/special black 4

1. Prepare 300 g. of soil at a time. Set up a screw-top plastic bottle with a magnetic stir bar on a stirring plate. The ethanol is added first, then calcium stearate, the water and lastly, the soot.

2. Set the stirring plate on high with the cap on the bottle or with parafilm (to

prevent evaporation). Stir until homogeneous.

3. Then place the closed or sealed container in the ultrasonic bath for 10 - 30 minutes.

(Continue if necessary, but no longer than 1 hour.)

Soil can be made up to a day ahead of time and stored at room temperature .

Substrate

For this test the high-gloss white ceramic tiles are initially cleaned with a mild abrasive cleaner, rinsed with water and wiped with ethanol. Subsequently the tiles are dried for 1 hour at 180°C in a preheated oven and then weighed.

Soil Application

1. If more than 1 hour from initial soil preparation has elapsed, place the closed bottle of soil in the sonicator for 10 minutes, and then place it on a stir plate to mix for 5 minutes.

2. Set up a pre-test to determine the amount of soil that must be applied to achieve a final amount of 0.25 g. ± 0.02 g. after baking in 180^C oven for one hour.

3. Stack the clean tiles vertically on a slanted board under the hood .

4. Attach the hose for the spray gun to the nozzle for compressed air .

5. Add the soil to the reservoir of the spray gun . Remove the small screw cap located in the center of the reservoir lid .

6. Turn the air on to a pressure level of about 50 psi.

7. The spray gun trigger has two positions. The first position just blows air and the second position blows out the soil. With sweeps of the spray gun apply the soil so that the soil layer is even and homogeneous. Dry the soil layer with the air position and then apply another. Continue adding soil layers to the tiles with drying in between, until the final amount of soil equals the amount achieved in the pre-test. 8. The tiles are dried for 1 hour at room temperature . Then bake the tiles for 1 hour, uncovered, in a horizontal position in a preheated circulating drying oven at 180°C to melt the calcium stearate.

9. Before testing, the tiles are stored for at least 24 hours at room temperature .

Weigh the tiles again and only use those that have a final soil weight of 0.25 ± 0.02g.

Soiled tiles may be used for testing up to 14 days. For comparative tests prepared tiles from the same batch should be used.

Testing

1. Testing is carried out in the form of a series of five exposure times . The exposure times are 10 minutes. (The times may be adjusted according to test objectives.)

2. Each application is accomplished by placing 0.5mL of undiluted cleaner with a pipette on an area 3 x 2 cm on the tile.

3. Four to six product applications may be placed on each tile . (See figure 1). Products are randomized and should appear in different positions on each tile. (The cleaning performance for each of the exposure times is arrived at from the mean value of the number of repetitions per product per measuring point.).

4. Subsequently the tile is rinsed under running water, and the loosened calcium stearate is removed mechanically by wiping a moist, fine-pored viscose sponge (90 x 40 x 40mm) once across the surface of the tile. Then the tile is rinsed with fully demineralized water and dried at room temperature .

Data

Analysis

1. After drying, the cleaning performance is visually assessed by three expert observers for each exposure time, estimating the soil removal in percent.

2. The cleaning performance for each exposure time is arrived at from the mean value of the three observations per measuring point.

3. To evaluate the total cleaning performance achieved, the mean percentage soil removal is plotted graphically against the cleaning time . A comparison of the cleaning performance against time provides evidence on the efficacy of the test cleaner.

4. Digital Imaging may also be used in place of the three observers . For % clean the following equation is used :

% clean = (Cleaned Tile - Soiled Tile) / (White Unsoiled Tile - Soiled Tile) * 100

Results

5 1.58 3.14

6 1.01 6.07

Avg. 0.69 4.11

Stdev> 0.63 1.61

* wt% of soil removed.

Here is it postulated that the vertical clean is superior due to the flow characteristics of the composition. The composition has been found to flow slowly down the vertical surface of the tile. As this occurs it is believed that the applied composition "rotates" and presents a new cleaning surface composition as it is slowly flows down the tile.

In comparison for the composition applies to a horizontal surface; since the thickened composition does not allows much (if any) movement within itself, once the active agents in the boundary layer between the surface being cleaned and the surface are exhausted, any remaining active agents cannot contact the surface to be cleaned.

t-Test Paired Two Sample for Means

A t-test is designed to highlight statistical significance between small sets of data (where n is greater than or equal to 3). The statistical test is used to make an assumption as if the sample size was larger. The main variables in this test are the averages and the standard deviations. The test will take into account these 2 parameters to determine the variability of the set of data. If the variability between both sets of data is large, then there will be no significant difference between them. If the variability is low and the averages are different, then there will likely be a significant difference between the data sets. The significance of a set of data can be determined at different confidence intervals, with 95% confidence being the standard. As seen in the test data, there is a low amount of variance between the data sets and the averages are quite different; therefore, at a 95% confidence interval we can conclude that the vertical test data is statistically superior to the horizontal test data.

Claims

1. A sprayable thickened aqueous composition for use as an acidic hard surface cleaning and disinfecting composition, comprising: i. a zwitterionic or betaine surfactant;

ii. an acid (preferably a water-soluble organic acid selected from lactic acid;

glycolic acid and citric acid);

iii. an alcohol, diol, glycol, ether or polyurethane based thickener;

iv. optionally an anionic and / or non-ionic surfactant;

v. a thickener;

vi. optionally, but desirably, one or more conventional additives; and

vii. water.

2. A composition according to claim 1, wherein the betaine surfactant is

cocamidopropyl betaine.

3. A sprayable thickened aqueous acidic composition, for use as a hard surface cleaning and disinfecting composition comprising: i. 0.1-2% wt. of one or more betaine surfactants;

ii. 0.1-10% wt. of an acid;

iii. 0.1-20% wt. of a thickener;

iv. 0-5% wt. of an anionic and / or non-ionic surfactant;

v. optionally up to 10% wt. of one or more additives, such as pH adjusting agents,

perfumes, fragrances and colouring agents;

vi. with the remaining balance to 100% wt. being water.

4. A process for cleaning limescale from a hard surface comprising the process step of contacting the hard surface having limescale thereon with a cleaning effective amount of the composition according to any of the preceding claims.

5. A process according to claim 4, wherein the process includes the use of a spray applicator.

6. A method for providing a germicidal benefit to a topical surface, especially a hard surface, such as a ceramic / glass / metal surface; the method comprising the step of: contacting a topical surface upon which the presence of one or more undesired pathogens, preferably bacteria, are known or suspected, with a composition according to any one of claims 1-3.