AU610460B1 - Prewash cleaner compositions - Google Patents

Description

i COMMONWEALTH OF AUSTRALIA Patent Act 1952 COMPLETE SPEC I F IC ATION

(ORIGINAL)

Class Int. Class Application Number Lodged Complete Specification Lodged Accepted Published Priority Related Art Name of Applicant Address of Applicant Actual Inventors Address for Service R C PRODUCTS PTY. LTD.

33 Hope Street, Ermi.~nton, N.S.W.

2114, Australia Raymond Neville Silvester Lindsay Ronald Showyin F.B. RICE CO., Patent Attorneys, 28A Montague Street, BALMAIN. 2041.

Complete Specification for the invention entitled: Prewash Cleaner Compositions The following statement is a full description of this invention including the best method of performing it known to us:- 8 017283 140990 c Si 2 Field of the Invention This invention relates to prewash cleaner compositions in the form of aerosols, more particularly to such compositions having suppressed flammability.

Background of the Invention Prewash cleaner compositions are used to treat textiles to selectively remove or enhance the removal of various soils that occur thereon. Typically these compositions are presented in aerosol form or in trigger dispensers to facilitate the application of the cleaner composition with some specificity to the soil affected area.

In use, a prewash cleaner composition is sprayed onto the soil affected area prior to the textile being laundered.

In the context of clothing textiles, it is perceived by consumers that collar and cuffs stains, which are sebaceous p: in nature, together with grease and oil stains are the most difficult to remove by normal washing methods. Accordingly, for effective cleaning performance, a suitable oil and grease solvent together with surfactant is required.

Although the prior art discloses numerous compositions of this type, for present purposes the discussion will be o limited to aerosol compositions.

One difficulty that has been addressed in the prior art o 1 is the need to avoid the generation of gases that will deplete the ozone layer around the earth. The chlorofluorocarbon propellants area class of gases for which evidence exists to indicate that they are one of the classes of gases responsible for ozone depletion.

Accordingly, aerosol prewash cleaner compositions were developed wherein chlorofluorocarbon propellants were typically replaced with hydrocarbons, such as butane and propane.

However, hydrocaibon propella j are highly flammable and therefore it was desirable in these compositions to provide some flammability suppression.

3 One way in which flammability was suppressed in these compositions was through the use of chlorohydrocarbon solvents. The use of such solvents had a double benefit in that flammability was suppressed whilst the chlorohydrocarbons functioned as efficient grease solvents.

Whilst the chlorohydrocarbons provided good cleaning performance, some of these compounds are also now suspected to contribute to the depletion of the ozone layer. For this reason, alternative grease solvents such as hydrocarbons have been used.

However, the combination of hydrocarbon solvent with hydrocarbon propellant results in a product that is very highly flammable. Thus, a product such as this when sprayed into a flame will have a very long and very hot flame. The flame is self-sustaining when taken away from 0o the ignition source and it burns back to the actuator nozzle. Accordingly, while such products are not I detrimental to the ozone layer and have effective cleaning performance, in use they are potentially quite dangerous.

Attempts have in the past been made to suppress the flammability of hydrocarbon solvent/hydrocarbon propellant formulations. Successful supression has been achieved by o" formulating products as oil-in-water emulsions or oil-in-water microemulsions. Australian patent No. 574715 S, 25 to Bristol-Myers Co. discloses a suppressed flammability formulation which is an oil-in-water microemulsion formulation. The formulation comprises a propellant composition having 23 35% of a water-immiscible liquid which is a solvent for the propellant; 15 water; 3 20% of a mixed surfactant system of at least one low HLB and at least one high HLB surfactant, the mixed surfactant system having a hydrophilic lipophilic balance sufficient to cause the water-immiscible liquid in which the propellant is dissolved to disperse as micro-droplets in the water upon shaking of the aerosol dispenser; and at least Od I I 4 by weight of the total weight of the composition of at least one normally gaseous flammable aerosol propellant provided to pressurise the aerosol dispenser. The resultant aerosol has suppressed flammability.

Australian patent 574715 teaches that suppressed flammability is achieved by virtue of the dissolution of the flammable propellant in the oil phase, which phase is present as dispersed microdroplets in the continuous water phase. On page 15a it is disclosed that the formulation can be used as a laundry pre-spotter composition.

However, while such formulations may have suppressed flammability, their cleaning performance particularly against oily stains is inferior. It is believed that the reason for this is as a result of the oil phase being the dispersed phase.

i* There are also formulations which are water based.

These rely on high levels of surfactant to achieve cleaning and again whilst having suppressed flammability, have inferior clea, ing performance against oily stains.

The present inventors have recognised the substantial difficulties in the prior art and have sought to provide 800' ,an aerosol prewash cleaner composition having suppressed o° flammability which has good cleaning performance, and avoids the use of solvents and propellants that are known or suspected of causing damage to the ozone layer.

Surprisingly, the present inventors have found that contrary to the teaching of Australian patent 574715, a formulation that is a water-in-oil microemulsion rather than an oil-in-water microemulsion will have suppressed flammability and good cleaning performance when based on the use of the propellant dimethylether. This is indeed an unexpected result particularly in view of the teaching of Australian patent No. 574715 and the specific disclosure therein in claim 20 of the use of dimethylether in the context of a "normally gaseous flammable propellant".

i r 5 Summary of the Invention Accordingly, the present invention consists in an aerosol prewash cleaner composition having suppressed flammability comprising:at least one hydrocarbon solvent in an amount of from 85% w/w, water in an amount of from 1 12% w/w, at least one nonionic surfactant in an amount of from 5 25% w/w and as propellant, dimethylether in an amount of from 8 25% w/w, said composition being in the form of a water-in-oil microemulsion.

Description of the Invention From the foregoing, it will be evident that whilst the present invention has suppressed flammability and has ingredients in common with the composition disclosed in S* Australian patent No. 574717, not only are the compositi ns in different states of emulsification but the o concentrations of a number of the ingredients are different. Thus, the minimum amount of water in 574717 is 15% whilst the maximum in the present invention is 12%.

The maximum amount of solvent in 574717 is 35% whilst the o° minimum in the present invention is 40%. At least 30% of S° 574717 composition is propellant whilst the present invention uses at most Therefore, given that the concentration ranges of ingredients in the present composition must be maintained within the specified limits to achieve a product in the form of a water-in-oil microemulsion having suppressed flammability and good cleaning performance, it is apparent that Australian patent 514717 does not disclose or suggest the present invention.

Furthermore, the prior art compositions based on chlorohydrocarbon solvents and hydrocarbon propellants are fundamentally different to the composition of the present invention notwithstanding that potentially dimethylether I- r

-A

6 could be used as a substitute propellant. This difference is that water must be rigorously excluded from these prior art compositions or otherwise hydrochloric acid is generated due to hydrolysis of the chlorohydrocarbons.

The presence of hydrochloric acid has a highly corrosive effect on aerosol cans.

A variety of hydrocarbon solvents may be used such as the isoparaffins and white spirit. Although the concentration of the solvent may range from 40 85% w/w, a range of from 50 85% w/w is preferred. It will be appreciated that mixtures of hydrocarbon solvents may be used.

The concentration of water in the composition is critical in that it aids to reduce flammability. This is thought to occur by virtue of water miscibility with the dimethylether and the nonionic surfactant. In the concentration range used in this composition, 1 12% w/w, the water is present in the form of microdroplets dispersed throughout the continuous oil phase.

If the concentration of water is increased above 12%, the resultant composition will not be a microemulsion and hence will lack stability. Rather, the composition will tend to form a milky emulsion which will be susceptible to separation into separate oil and water phases. Such separation will have adverse consequences both in production and in use. In production where typically a Sconcentrate is prepared and stored prior to filling with propellant into aerosol cans, the relative concentration of ingredients in the aerosol could well be outside the required ranges. Hence the cleaning performance and flame supression will likely be adversely effected.

Similarly, if separation of the product occurs in the aerosol can, a composition will be dispensed which does not have the required cleaning properties with suppressed flammability.

If on the other hand the concentration of water is

I

-7too low, flame suppression will be minimal and unacceptable.

The present inventors have found that a preferred concentration range of water is from 2 7% w/w.

At least one nonionic surfactant is included in the inventive composition. A variety of nonionic surfactants may be used of which fatty alcohol ethoxylates are preferred. These are widely and readily available and the person skilled in the art would readily recognise those surfactants that are suitable to maintain the composition in the form of a water-in-oil microemulsion.

It must also be recognised that the surfactants also function in cleaning.

A preferred range of concentration of nonionic surfactant(s) is 10 20% w/w.

In order to obtain the requisite flammability suppression, dimethylether must be used as the propellant in an amount of from 8 25% w/w. Although dimethylether 4 4 when compared with butane is known to be less flammable, have a lower combustion heat output, and to have a higher lower explosion limit, its choice as a propellant for this a composition is not an obvious one. Thus, it is still regarded as a flammable propellant and due to its high pressure it would be expected to have a long flame length. Furthermore, in all other regards, the prior art teaches its equivalence to a variety of other flammable propellants.

The compositions of the invention may include other ingredients such as corrosion inhibitors, perfumes and the like. The person skilled in the art would recognise such additives and be able to readily determine the concentration in which they are to be used.

The compositions of the present invention have suppressed flammability in that when sprayed into a flame and then removed from the ignition source, the flame is barely self-sustained and does not burn back to the 1. I I_ 8 actuator nozzle. This is in marked contrast to the hydrocarbon solvent/hydrocarbon propellant prior art compositions. Furthermore, it is equal to if not better than prior art compositions based on chlorohydrocarbon solvents/hydrocarbon propellants.

In order to obtain maximum suppression of flammability and to optimise spray characteristics, the valve and actuator combination used in the aerosol dispenser may be varied. The person skilled in the art without having to resort to undue trial and experimentation would be able to readily select a suitable combination of valve and actuator.

The compositions of the present invention may be «readily prepared in the following manner:- 1. The surfactant is dissolved in the hydrocarbon solvent.

°o 2. Water is added to the surfactant solution and stirred o o until clear.

3. Additives such as corrosion inhibitors and perfume are then added with stirring.

4. The resultant concentrate is then filled into aerosol containers using the requisite amount of dimethylether.

Dio In order to better understand the nature of the present invention, a number of examples are set out oS 25 below. All of the examples were prepared as described above.

Example 1 BO 4 Ingredient w/w Isoparaffin solvent 68.5

C

1 2 1 4 fatty alcohol ethoxylate (6 moles ethylene oxide) 12.0 Deionised water Perfume 0.3 Corrosion inhibitor 0.2 Dimethyl ether propellant 17.0 r i 9 Example 2 White spirit solvent 59.6

C

1 2 1 4 fatty alcohol 18.0 ethoxylate (4 moles ethylene oxide) Deionised water Perfume 0.3 Corrosion inhibitor 0.1 Dimethylether propellant 17.0 Example 3 White spirit solvent 59.6

C

1 2- 1 4 fatty alcohol ethoxylate (4 moles 14.0 ethylene oxide) C12- 1 4 fatty alcohol ethoxylate (8 moles ethylene oxide) Deionised water Perfume 0.3 Corrosion inhibitor 0.1 Dimethylether propellant 17.0 A number of comparative examples of prior art compositions were prepared as follows:- Example 4 Ingredient w/w White spirit solvent 64.7 Nonionic surfactant as Example 3 18.0 Perfume 0.3 Hydrocarbon H40 propellant 17.0 1 10 Example White spirit solvent Mineral turpentine Nonionic surfactant as Example 3 Perfume Hydrocarbon H40 propellant Example 6 61.7 18.0 0.3 17.0 1,1,1-Trichloroethane solvent 49.7 White spirit solvent 12.0 Mineral turpentine Nonionic surfactant 18.0 Perfume 0.3 Hydrocarbon H40 propellant 17.0 The cleaning performance of Example 3 and comparative Example 6 were evaluated using the following protocol:- The test results are set out in Tables 1 and 2.

1. FABRIC White polyester/cotton 65/35 Cotton 100% 2. WASHING CONDITIONS 2.1 Hoover 635 top loading automatic washing machine, 12 minute wash, 2 rinses.

2.2 Wash temperature: Cold, record actual temperature 2.3 Detergent: 96g of powder detergent Omo, Fab or equivalent per low fill 2.4 Only test and control swatches are washed in machine, no dummy load.

Swatches are dried in tumble dryer before evaluation.

11 3. STAINS Test Stains: Sump oil Engine grease Biro, blue Texta pen Lipstick, red (record brand used) Shoe polish black (record brand used) Clay Grass (juice ex blended fresh grass cuttings) Red wine (Record type and brand used) Black coffee (Record type and brand used) White tea 'ord type and brand used) (applied to soak approx circle) (applied in 50mm circle) (applied approx over 10 x area) (solvent based felt pen applied over 10 x 50mm area) (applied over 10 x 50mm area) (dabbed lightly onto circle) (applied to approx 10 x area) (applied to approx 10 x area) (applied to soak approx circle) (applied to soak approx. circle) (applied to soak approx. circle) 12 Fabric swatches are to be washed according to washing conditions given above prior to staining.

Always prepare one set of stains more than number of samples to be evaluated and wash without prewash treatment. Select swatches randomly for samples to be evaluated.

4. TIhING Standard time between staining and application is 24 hours.

5. RATING a) Stains are rated on a 0-5 scale. 0 indicates complete removal of stain, 5 indicates no removal of stain.

b) Stains are rated by two experienced people, who agree on a rating between them. As a check, stains can be Srated independently on two different days.

c) Stains are rated in strong "south" daylight (would be Snorth light in northern hemisphere). White swatches are laid flat on a dark background for rating; this procedure makes rating easier and more reproducible, especially for oil stains.

6. TEST DESIGNS Sa) This varies depending on the aim of the test. Extra parameters such as age of stain or washing conditions can be varied if necessary.

b) An "untreated" control stain is always washed in the same load as each sample tested with prewash. A number of different stains are tested in the same washload (along with their corresponding "untreated" controls) but only one prewash product is tested in the one washing machine load.

c) Wherever possible, ratings are only compared within the one set of trials.

_LI jl i_ i I -r rl I ~1 11111~ r 13 TABLE 1 Cleaning Performance 100% Cotton Rating Stain Example 3 Example 6 Grease and oil Proteinaceous Bleachable Particulate Test 1 2 3 2.5 1.3 2.1 1.3 3.8 3.0 2.5 3.5 2.8 2.8 4.2 2.3 Test 1 2 3 2.1 1.9 2.3 1.4 3.8 1.8 2.7 2.4 2.5 4.0 Cleaninq TABLE 2 Performance 65/35 Polyester Cotton Rating Stain Example Example 6 Grease and oil Proteinaceous Bleachable Particulate Test 1 2 3 2.0 2.5 1.8 2.0 2.8 2.8 2.6 3.2 2.9 2.0 3.3 1.5 Test 1 2 3 1.7 3.2 2.9 2.0 1.8 2.1 2.5 2.1 2.0 3.3 From these test results, it is evident that Example 3 had at least equivalent cleaning performance to comparative Example 6.

The flammability of Example 3 and the Comparative Examples 4-6 was determined according to the Flame Propagation test set out in Australian Standard 2278-1986. The results are set out in Tables 3 and 4.

i r I 111~ 14 Table 3 Flame Propagation Example 3 Flame length (mm) Sustain Burnback 450-500 no no Full can Halffull can Quarterfull can Temp.

mild mild very mild 450-500 450-500 slight no Table 4 Flame Propagation Comparative Examples Flame length (mm) Sustain Burnback Temp.

Example 4 about 500 yes yes hot voluminous Example 5 about 500 yes yes hot voluminous Example 6 450-500 yes no N/A From these results, it is evident that the flammability of the Example 3 is lower than that of the prior art comparative examples.

Although the present invention has been described with reference zo certain preferred embodiments and examples, it will be appreciated by those skilled in the art that numerous variations and modifications are possible without departin- from the spirit or scope of the invention.

4ila( 1 ~BI B a a

Claims (2)

1. An aerosol prewash cleaner composition having suppressed flammability comprising:- at least one hydrocarbon solvent in an amount of

40-85% w/w; water in an amount of from 1-12% w/w; at least one nonionic surfactant in an amount of from 5-25% and as propellant, dimethyl ether in an amount of from 8-25% w/w, said composition being in the form of a water-in-oil microemulsion. 2. A composition as in claim 1 wherein at least one hydrocarbon solvent is present in an amount of from 50-85% ow/w. 0 0 0 3. A composition as in claim 1 or claim 2 wherei. the water is present in an amount of from 2-7% w/w. 0 0 0 o S 4. A composition as in any one of claims 1 to 3 wherein So0 the at least one nonionic surfactant is present in an amount of from 10-20% w/w. A composition as in any one of claims 1 to 4 wherein there are two nonionic surfactants present. o u,0 6. A c.:osition as in any one of claims 1 to 5 wherein o .o the at least one nonionic surfactant is an ethoxylated "0 0 fatty alcohol. S, 7. An aerosol prewash cleaner composition having suppressed flammability and being in the form of a microemulsion substantially as hereinbefore described with s o reference to any one of Examples 1, 2 or 3. C 0 DATED this 14th day of September 1990 R C PRODUCTS PTY. LIMITED Patent Attorneys for the Applicant: F.B. RICE CO.