Field of Invention

The present invention relates to a method, composition and device for reducing the volume of foam, and to the use of said method, composition and device. In particular, the present invention relates to the use of a composition and optionally an associated device in the destruction of foam as is typically formed by surfactants on the surface of fluids, and as is typically deposited on surfaces.

Background

The formation of foam on the surface of fluids, such as water, can prove problematic in domestic and commercial processes. Foam is often formed when surfactants are added to water. For example, the use of washing up liquid, soap or bubble bath in water can create a layer of foam on top of the water. When the water is drained away, this layer of foam often settles on the vessel in which the water was held, for example, a bath or sink. In order to remove the foam, it is common practice to rinse the vessel with water several times. This rinsing process uses copious amounts of water, and thus is environmentally unsound and expensive.

Several commercial processes involve the use of large vessels in which fluids are mixed or otherwise processed. In many such commercial processes, such as (for example) paper manufacturing, fermentation, the preparation of chemicals, and processes involving the use of surfactants, surface foam forms on top of the fluids. When foam is present in processing fluids or processing liquids this can cause a reduction in pump efficiency or capacity, a reduction in the capacity of storage tanks, unwanted bacterial growth, the formation of unwanted deposits, reduced effectiveness of the fluid, formation problems (such as inhomogeneous products being formed), drainage problems in (for example) sieves and filters, inaccurate fluid level readings and overflow of fluid. Further associated problems include the cost of replenishing the liquids used and the cost of material rejection due to imperfections.

The problems outlined above can reduce the speed at which fluids can be processed and can reduce the availability of process equipment due to, for example, cleaning of the vessels. Cleaning of the vessels can also prove problematic as foam often forms on the top of cleaning solutions used to clean such vessels. This fluid may also be deposited on the surface of the vessel when the cleaning solutions are drained from the vessels. Again, in order to remove the foam, it is common practice to rinse the vessel with water several times. This rinsing process uses copious amounts of water, and thus is environmentally unsound and expensive.

Therefore, it is an object of the present invention to obviate or mitigate at least some of the disadvantages of the prior art. A further object of the invention is to provide a composition and method of use thereof to destroy, or at least reduce the volume of, foam.

Disclosure of Invention

According to a first aspect of the invention there is provided the use of a composition comprising an aluminium salt in the reduction in volume of foam.

Generally the volume of foam is reduced by at least 50 % by volume;

typically by at least 70 % by volume; suitably by at least 90 % by volume; more suitably by at least 95 % by volume; most suitably by at least 99 % by volume.

The reduction in volume may result in the destruction of foam.

The foam is typically a surfactant-based foam. The surfactant-based foam may be the result of the use of a domestic and/or industrial cleaning agent. Typical domestic and industrial cleaning agents include: soap, shower gel, washing up liquid, bubble bath and industrial cleaning solutions.

Typically the composition comprises from about 2 % w/w to about 8 % w/w aluminium salt.

Typically the composition comprises at least about 2 % w/w aluminium salt, more typically at least about 4 % w/w aluminium salt, most typically at least about 8 % w/w aluminium salt.

The particle size of the aluminium salt may be from about 0.1 to about 200 μιτι. The mean particle size may be from about 3 to about 20 μιτι.

Alternatively, the mean particle size is from about 20 to about 50 μιτι. In another alternative, the mean particle size is from about 0.1 to about 3 μιτι.

The aluminium salt may be selected from the group consisting of:

aluminium chlorohydrate, aluminium chloride, aluminium zirconium tetrachlorohydrex and aluminium zirconium chlorohydrate.

Preferably the aluminium salt is aluminium chlorohydrate.

The inventors have surprisingly found that aluminium salts and, in particular, aluminium chlorohydrate and the like, substantially reduce the volume of foam, typically destroying the foam. The foam may be residual foam left on the surfaces of vessels (such as baths, or reactor vessels), or foam that has formed on top of a fluid, such as an aqueous surfactant solution.

The composition may further comprise a carrier.

Typically the composition comprises from about 3.1 % w/w to about 12.4 % w/w carrier.

The carrier may be selected from the group consisting of: cyclomethicone, dimethicone, and dimethicone copolyol.

Preferably the carrier is cyclomethicone.

The composition may further comprise an anti-settling agent.

Typically the composition comprises from about 0.16 % w/w to about 0.64 % w/w anti-settling agent.

The anti-settling agent may be selected from the group consisting of: bentonites, hectorites and montmorillonites.

Preferably the anti-settling agent is disteardimonium hectorite.

The composition may further comprise a propellant.

The composition typically comprises from about 78.8 % w/w to about 94.8 % w/w propellant. The propellant may be selected from the group consisting of: butane- isobutane-propane and compressed air.

Preferably the propellant is butane-isobutane-propane. The butane- isobutane-propane may comprise 54 % by volume butane, 24 % by volume isobutane, and 22 % by volume propane.

The composition may further comprise an activator. The composition typically comprises from about 0.03 % w/w to about 0.12 % w/w activator.

The activator can be chosen from the group consisting of: propylene carbonate and ethanol. Typically, the activator is propylene carbonate.

According to a second aspect of the invention there is provided a composition for the reduction in volume of foam, said composition comprising at least about 2 % w/w aluminium salt, from about 3.1 % w/w to about 12.4 % w/w carrier, and from about 0.16 % w/w to about 0.64 % w/w anti-settling agent.

The reduction in volume may be the destruction of foam, and the foam may be a surfactant-based foam. The surfactant-based foam may be the result of the use of a domestic and/or industrial cleaning agent. Typically the domestic and/or industrial cleaning agent is selected from the group consisting of: soap, shower gel, washing up liquid, bubble bath and industrial cleaning solutions. Typically the composition comprises at least about 4 % w/w aluminium salt, more typically at least about 8 % w/w aluminium salt.

Typically the composition comprises from about 2 % w/w to about 8 % w/w aluminium salt.

Typically the particle size of the aluminium salt is from about 0.1 to about 200 μιτι. The mean particle size of the aluminium salt may be from about 3 to about 20 μηη.

The aluminium salt may be selected from the group consisting of:

aluminium chlorohydrate, aluminium chloride, aluminium zirconium tetrachlorohydrex and aluminium zirconium chlorohydrate. Preferably the aluminium salt is aluminium chlorohydrate.

The carrier may be selected from the group consisting of: cyclomethicone, dimethicone, and dimethicone copolyol. Preferably the carrier is cyclomethicone.

The anti-settling agent may be selected from the group consisting of: bentonites, hectorites and montmorillonites. Preferably the anti-settling agent is disteardimonium hectorite.

The composition may further comprise a propellant.

Typically the composition comprises from about 78.8 % w/w to about 94.8 % w/w propellant. The propellant may be selected from the group consisting of: butane- isobutane-propane and compressed air. Preferably the propellant is butane-isobutane-propane. The butane- isobutane-propane may comprise 54 % by volume butane, 24 % by volume isobutane, and 22 % by volume propane.

The composition may further comprise an activator.

The composition typically comprises from about 0.03 % w/w to about 0.12 % w/w activator.

The activator can be chosen from the group consisting of: propylene carbonate and ethanol. Typically, the activator is propylene carbonate.

According to a third aspect of the present invention there is provided a method of reducing the volume of foam, said method involving the step of applying to a body of foam the composition as described herein.

Preferably the composition is applied as an aerosol.

According to a fourth aspect of the present invention there is provided a device for reducing the volume of foam, said device comprising the composition as described herein, wherein said device is configured to dispense the composition as an aerosol.

The method of the present invention, and the products derived thereform, will now be described by way of example only. Examples

Preparation of compositions

A composition in accordance with the invention was prepared as follows.

A portion of cyclomethicone was added to a mixing vessel containing a high shear mixer. The mixer was operated at high shear and

disteardimonium hectorite was added slowly and mixed until dispersed. The propylene carbonate was then added with continued high shear mixing until a gel formed. A second portion of the cyclomethicone was added and the mixture was stirred until uniform. The aluminium

chlorohydrate powder was then added with high shear mixing and the mixing was continued until all of the powder was added, and a

homogeneous slurry was formed.

The resultant product is a dispersion of aluminium chlorohydrate powder in a volatile silicone oil carrier.

The method as described was used to prepare compositions as described below where all figures are % w/w.

Composition 1

Butane-isobutane-propane 94.71

Cyclomethicone 3.10

Aluminium chlorohydrate 2.00

Disteardimonium hectorite 0.16

Propylene carbonate 0.03

Composition 2

Butane-isobutane-propane 89.42 Cyclomethicone 6.20

Aluminium chlorohydrate 4.00

Disteardimonium hectorite 0.32

Propylene carbonate 0.06

Composition 3

Butane-isobutane-propane 78.84

Cyclomethicone 12.40

Aluminium chlorohydrate 8.00

Disteardimonium hectorite 0.64

Propylene carbonate 0.12

Preparation of aerosol

An aerosol device (dispenser device) was prepared as follows.

A measured amount of the components of the composition (without the butane-isobutane-propane) was added to a can suitable for use as an aerosol can. Optionally, a measured amount of fragrance can be added. A valve was added to the top of the can and crimped into place. The can was then filled with the suitable measured amount of butane-isobutane- propane (propellant) through the valve. An actuator was placed on the valve stem and was covered with a cap.

The valve and can are of the conventional type well known in the field of aerosols and propellants, and the valve may include the following components such that it interacts with the actuator, and such that it may allow delivery of substances from within the can.

The valve can comprise of a valve cup which sits on top of the can and which contains an orifice through which a stem protrudes. The proximal end of the stem attaches to an actuator, whilst the distal end is in contact with a stem gasket, and a spring that sits in a housing. The housing is attached to a dip tube which extends into the can such that the contents thereof can be delivered through the valve.

Use of composition

The aerosol device containing the composition was used to destroy residual foam, which remained in a domestic bath after use, as follows. Test 1 - Composition method

At the start of the test, approximately 25% of the volume of the bath contained foam. The composition as described herein was sprayed as an aerosol onto the foam. After 10 seconds all of the foam had been removed. No water was required in the removal, and there was no requirement to rinse the bath, thus no water was used.

For comparison, a second test (Test 2) was carried out using the conventional repeated rinsing method to remove the foam from the bath. Test 2 - Conventional method

At the start of the test, approximately 25% of the volume of the bath contained foam. Water was used to rinse the foam from the bath at a rate of approximately 2 pints (approximately 1 .1 litres) every three seconds. After approximately 240 seconds the foam had been removed. The total amount of water used was approximately 160 pints (approximately 91 litres).

The present invention provides a composition for use in the reduction in volume of foam, and in particular in the destruction of foam that has settled on the surface of liquids or solids. Having described examples of specific embodiments, the invention will now be described in general terms. Herein, in relation to the formulation, all percentages are by weight based on the entire formulation, including the propellant unless otherwise stated. It will be understood that the amount of propellant used can be varied to ensure that the total amount of components in the formulation adds up to 100 % w/w.

The compositions as described herein comprise an aluminium salt. The particle size of the aluminium salts often falls within the range of 0.1 to 200 μιτι with a mean particle size often from 3 to 20 μιτι. Both larger and smaller mean particle sizes can also be contemplated such as from 20 to 50 m or 0.1 to 3 μιτι.

The aluminium salt used can typically be of the type used in

antiperspirants including, for example, aluminium chlorohydrate, aluminium chloride, aluminium zirconium tetrachlorohydrex and aluminium zirconium chlorohydrate.

The compositions as described herein typically also comprise a carrier. The carrier can be selected from both volatile and non-volatile liquids and mixtures which contain both a volatile and a non-volatile liquid. The relative proportions of the volatile and non-volatile liquids are at the discretion of the user and will usually be chosen in association with the other formulation constituents in order that the formulation exhibits the desired combination of properties. In some formulations, the carrier includes a volatile liquid silicone, i.e. liquid polyorganosiloxane. Volatile polyorganosiloxanes can be linear or cyclic or mixtures thereof. Preferred cyclic siloxanes include

polydimethylsiloxanes and particularly those containing from 3 to 9 silicon atoms and preferably not more than 7 silicon atoms and most preferably 4, 5 and/or 6 silicon atoms, otherwise often referred to as cyclomethicones. Preferred linear siloxanes include polydimethylsiloxanes containing from 3 to 9 silicon atoms.

The volatile silicones can also comprise branched linear or cyclic siloxanes such as the aforementioned linear or cyclic siloxanes substituted by one or more pendant -O-Si(CH ₃ ) ₃ groups. Examples of commercially available silicone oils include oils having grade designations 344, 345, 244, 245 and 246 from Dow Corning Corporation; Silicone 7207 and Silicone 7158 from Union Carbide Corporation; and SF1202 from General Electric.

The carrier employed in many compositions herein can alternatively or additionally comprise non-volatile silicone oils, which include polyalkyl siloxanes, polyalkylaryl siloxanes and polyethersiloxane copolymers.

These can suitably be selected from dimethicone and dimethicone copolyols. Commercially available non-volatile silicone oils include Dow Corning 556 and Dow Corning 200 series.

Silicon-free carriers can be used instead of, or in addition to liquid silicones. Silicon-free hydrophobic organic liquids which can be employed include volatile or non-volatile liquid aliphatic hydrocarbons such as mineral oils or branched aliphatic hydrocarbons often selected to exhibit a low viscosity. Examples of liquid hydrocarbons are hydrogenated polyisobutene, polydecene, and paraffins and/or isoparaffins of at least 10 carbon atoms. Other suitable constituents of hydrophobic carriers are liquid aliphatic or aromatic esters. Suitable aliphatic esters contain at least one long chain alkyl group, such as esters derived from Ci to C20 alkanols esterified with a Cs to C22 alkanoic acid or Ce to C10 alkanedioic acid. These esters include isopropyl myristate, lauryl myristate, isopropyl palmitate, diisopropyl sebacate and diisopropyl adipate.

Suitable liquid aromatic esters include fatty alkyl benzoates alkylene dibenzoate, alkoxylated alkyl benzoate or a polyalkylene oxide dibenzoate, or a mixture of two or more. The alkyl group is linear or branched and often contains at least 8 carbons, in many instances up to 25 carbons, e.g. from Cs to C18 or is a mixture, e.g. Ci2 to Ci ₅ . The term alkylated herein includes alkylene groups which are terminated at each end with a benzoate group. The alkylene group often contains from 2 to 6 carbons and can be linear or branched, a suitable example of linear being propylene.

The compositions as described herein typically also comprise an anti- settling agent. The anti-settling agent can be an inorganic material.

Commonly used inorganic anti-settling agents are fine particulate silica or silicates. These include fumed silica, e.g. those available from Degussa under the tradename Aerosil. The silicates include complex silicates such as clays, such as bentonite, hectorite or montmorillonite. In particular the anti-settling agent can be disteardimonium hectorite. The surface of the particulate clay can be treated with a hydrophobe so as to render it more compatible with the carrier, as for example in Bentone(TM) 38. Suitable anti-settling agents include structurants such as polyamides as discussed in U.S. Pat. No. 5,500,209, including in particular terpolymers (e.g. Elvvamide 8061 (TM)) and polyamides based on complex fatty acids. Such polyamides may be derived from organic diamines containing 2 to 12, preferably 2 to 8 carbon atoms, condensed with di- or poly carboxylic acids containing 4 to 20 carbon atoms per carboxylic acid group

(Versamid(TM) or Unirex(TM)). Aromatic polyamide resins having pendant silyl groups are described in U.S. Pat. No. 5,243,010. The polyamides can be modified with silicon-containing moieties such as siloxanes containing lower alkyl or phenyl groups, as described for example in U.S. Pat. No. 5,874,069. Alternative polymers are described in U.S. Pat. No. 5,919,441 which are copolymers of organosiloxane diamines with dimeric acids. Related polymers described in U.S. Pat. No. 5,919,441 comprise polyurea in which organosiloxane diamines are reacted with a isocyanurate.

A still further class of polymer, which are also commonly regarded as a structurant, and that can be used as an anti-settling agent are siloxane elastomers, namely organic polysiloxanes α, ω which have been cross linked, either lightly or extensively. Cross linking can arise in one way from reaction between Si-H groups and unsaturated groups, such as Si- vinyl groups or α, ω dienes, typically Pt catalysed. The elastomers are often blends containing absorbed volatile silicones. Examples include DC9010, DC9040 and DC9070 (Dow Corning Inc) KSG-17 (Shin-Etsu

Chemical Co) SF 839 GE (General Electric) and Gransil SR-CYC (Grant Industries Inc). Various at least lightly cross-linked siloxane elastomers are described in U.S. Pat. No. 5,922,308. The dispenser can be in the form of an aerosol, typically containing a propellant gas (or gas mixture) such as a butane-isobutane-propane mix. The butane-isobutane-propane typically comprises 54 % by volume butane, 24 % by volume isobutane, and 22 % by volume propane, although other ratios of components as are known in the art can also be used. An aerosol is understood to be a suspension of fine solid particles or liquid droplets in a gas. Alternative propellant gases include

compressed air.

Alternatively, the aerosol can be in the form of a pump spray which are well known mechanisms of providing a fine spray of a composition.

The compositions as described herein typically also comprise an activator, suitable for activating the anti-settling agent. Suitable activators are polar activators such as low molecular weight compounds of a polar nature. The most commonly used polar activators are propylene carbonate, acetone, methanol/water and ethanol/water. Several other low molecular weight alcohols are also used in the field. When using an alcohol as a polar activator, it may contain at least 5% water. If water is absent the polar activator will not function efficiently, thus reducing final product

performance. Selection of the polar activator will depend on various considerations such as health and safety factors, availability, efficiency, cost, and compatibility with the system. Typically, the activator comprises propylene carbonate or ethanol, or mixtures thereof. The composition described herein can be used in the manufacture of an aerosol. The use of the composition and the aerosol device described herein is effective in the reduction in volume of and/or in the destruction of foam. Optional ingredients in compositions of this invention can include deodorants, for example at a concentration of up to about 10% w/w.

Suitable deodorant actives can comprise deoperfumes, and/or

microbicides, including particularly bactericides, such as chlorinated aromatics, including biguanide derivatives, of which materials known as Triclosan (Igasan DP300(TM)), Tricloban(TM), and Chlorhexidine warrant specific mention. Another class comprises biguanide salts such as available under the trade mark Cosmosil(TM). Bleaching and/or sanitising agents can also be added to the compositions as described herein.

Various modifications and variations to the described embodiments of the invention will be apparent to those skilled in the art without departing from the scope and spirit of the invention. Although the invention has been described in connection with specific embodiments, it should be understood that the invention as claimed should not be unduly limited to such specific embodiments. Indeed, various modifications of the described modes of carrying out the invention which are obvious to those skilled in the art are intended to be covered by the present invention.