EP2909296B1 - Surfactant-containing foams - Google Patents

Description

The invention relates to surfactant-containing foams, processes for the preparation of surfactant-containing foams and packaged products containing surfactant-containing foams.

Surfactant-containing agents are known in a wide variety of forms. Thus, the consumer knows solid, for example tablet-shaped or granular detergents and liquid or gel-based cleaners for hard surfaces. Also known are agents, for example dishwashing detergents or hand soaps, which are present in the packaging in the liquid state, but which the consumer converts into a foam before use by means of an intumescent metering device and metered directly into the washing water or into the palm of the hand (for dishwashing detergents, for example WO 2007/003302 A1 ). Some bath cleaners are also sprayed directly onto the surfaces to be treated as foam using special foam spray nozzles. Also, shaving foam is foamed until the dosage by the consumer.

The surfactant-containing foams hitherto known to the consumer are accordingly always produced by the consumer only directly before application from a foamable liquid product and a two-component pump. An advantage of this dosage form is that the foamable liquid product - in addition to the presence of foam-forming substances such as surfactants - no special requirements are made. Almost any conventional detergent formulation should be capable of being converted into a short-term stable, flowable foam by means of a suitable pumping device. However, a significant disadvantage is that the e.g. the amount required by a detergent for a single wash load is so great that it can not readily be foamed with a manually operated pump, as this would be either too strenuous, because too many pump surges would have to be performed or such a large pump would be used would have, which would be too expensive for single use and therefore would have to be used several times. It is doubtful whether the consumer would be willing to buy an expensive pump, which he would have to constantly mount on new storage containers to avoid new costs and waste.

However, foams are particularly interesting for the consumer in the field of surfactant-containing agents, detergents and cleaning agents on the one hand, but also cosmetics on the other hand. The consumer expects delicacy, gentleness, protection and care from a foam, but also improved stain removal performance, since he assumes, for example, that foam adheres to a polluted surface for longer or more intensively than, for example, a low-viscosity liquid and thus can last longer.

Since foams are thermodynamically unstable and at best low-viscosity liquids can be temporarily stabilized by the use of surface-active substances, it has hitherto not been possible to offer the consumer a long-term stable surfactant-containing foam which, moreover, is preferably flowable.

It is therefore the object of the invention to stabilize a surfactant-containing foam, so that it can be given to the consumer in packaged form "ready to use" on the hand.

A foam in the sense of the present invention is understood as meaning a disperse system of a gas or gas mixture in a continuous liquid phase, ie a structure of gas-filled cells, which are bounded by liquid cell webs. The term liquid phase is used here for the fluid of the cell bridges.

The object is achieved by a surfactant-containing foam according to claim 1, whose liquid phase has a yield point.

Surprisingly, it has been found that a surfactant-containing foam whose liquid phase has a yield point is significantly more stable over the long term, ie it separates significantly more slowly in the liquid phase and gas phase than a surfactant-containing foam whose liquid phase has no yield point.

The yield stress is the highest shear stress below which a substance behaves like an elastic solid or, conversely, the smallest shear stress above which a plastic substance behaves rheologically like a liquid.

To determine the yield point in the context of the present invention, the procedure was as follows: The sample was in the rheometer (rotational rheometer from TA-Instruments, type AR G2, shear stress controlled rheometer, cone-plate measuring system with 40 mm diameter, 2 ° cone angle, 20 ° C) with a time-increasing shear stress o (t) acted upon. The shear stress was increased in a period of 30 minutes from the smallest possible value (for example 0.01 Pa) to a value above the expected yield value (eg 80 Pa). As a function of this shear stress σ , the deformation γ of the sample is measured.

For evaluation the data are plotted in a log log plot (log γ against log σ ). The yield point, if present, can be recognized by a sudden change in the slope of the curve. At shear stresses below the yield point, the sample reacts purely elastically and the slope of the curve is ideally one. For shear stresses above the Yield limit begins viscous flow and the slope of the log γ (log σ ) curve increases dramatically. The yield point is determined from the intersection of the tangents to both curve sections.

The yield strength of the liquid phase is at least 0.1 Pa, more preferably at least 1 Pa and especially at least 2 Pa. In appropriate surfactant-containing foams, the leakage of the liquid phase from the cell webs is particularly well prevented, so that the cell web thickness kept constant, the separation of the surfactant-containing foams in liquid phase and gas phase prevented and thus the long-term stability of the surfactant-containing foams is increased ,

A particularly advantageous and attractive aesthetics of the surfactant-containing foam and a further improvement in storage stability can be achieved if the liquid phase itself at a shear rate of 10 s ^-1 and a temperature of 20 ° C, a viscosity of 0.1 to 50 Pas having. The viscosity of the liquid phase is particularly preferably from 1 to 20 Pas, in particular from 2 to 10 Pas. In such cases, the liquid phase containing surfactant-containing foam is pourable, which corresponds to a particularly preferred embodiment of the present invention, since the consumer can dose the foam with such a viscosity, for example, from a dimensionally stable container out. The adjustment of the viscosity in this range also contributes to the stabilization of the cell webs and thus to increase the long-term stability of the respective surfactant-containing foam. The viscosity of the liquid phase is determined with the same experimental setup as described above for the yield point. However, it is worked in a program and with a plot in which the viscosity is given as a function of the shear rate.

To adjust the suitable rheology of the liquid phase, ie to form the yield point and the suitable viscosity, the liquid phase preferably contains one or more thickeners and / or is in the form of a liquid-crystalline surfactant phase, preferably a lamellar surfactant phase.

Suitable thickeners from the group of naturally occurring polymers are, for example, agar-agar, carrageenan, tragacanth, gum arabic, alginates, pectins, polyoses, guar flour, locust bean gum, starch, dextrins, gelatin and casein. Modified natural products come mainly from the group of modified starches and celluloses, examples which may be mentioned here carboxymethylcellulose and other cellulose ethers, hydroxyethyl and propylcellulose and core flour ethers. Furthermore, microfibrillar bacterial celluloses are suitable. A large group of thickeners, which find wide use in a variety of applications, are the fully synthetic polymers such as polyacrylic and Polymethacrylic compounds, vinyl polymers, polycarboxylic acids, polyethers, polyimines, polyamides and polyurethanes. Also suitable and preferred is xanthan.

Structured surfactant systems with lamellar and / or spherulitic phases are typically formed by the interaction of surfactants with dissolved electrolyte salts and / or cosurfactants.

Lamellar surfactant phases are on a microscopic scale two-phase systems in which surfactant bilayers are arranged as parallel lamellae. These lamellae alternate with an aqueous phase. Macroscopically they usually form an opaque gel-like, single-phase system. The surfactant bilayers of a lamellar phase can be "stacked" in parallel, with mesoscopic domains having the same orientation or being spherically "wound up". The latter systems are called vesicles or spherulites. Lamellar surfactant phases can be formed when a surfactant system is mixed with inorganic salt and optionally a cosurfactant. At sufficiently high concentration, many surfactants form lamellar phases even without salt and co-surfactant, but these are usually too viscous for the present invention and there is no flowable foam.

It has surprisingly been found that by adding selected amounts of an inorganic salt and a cosurfactant to a surfactant-containing liquid phase, a lamellar liquid phase with yield value is obtained, which can be used to form long-term stable surfactant-containing foams. For the purposes of the present invention, a co-surfactant is understood to mean an amphiphilic molecule which has a hydrophilic head group which is particularly small in comparison with customary surfactants, for example a fatty alcohol, a fatty acid, a monoglyceride or a lower ethoxylated fatty alcohol with less than or equal to 3 mol ethylene oxide. Co-surfactants are usually very poorly soluble in water alone, but are incorporated in the presence of soluble surfactants in their micellar aggregates and affect their shape. For example, they can induce transition to a lamellar phase at appropriate concentration ratios.

This surfactant-containing liquid phase is able without the addition of a polymeric thickener in a position to form a long-term stable surfactant-containing foam. The ability to dispense with polymeric thickener, not only has the advantage that the funds can be made easier and cheaper, but also undesirable side effects of a polymeric thickener, such as graying in the treatment of textiles, can be avoided. Accordingly, in a preferred embodiment, the surfactant-containing liquid phase is free of polymeric thickeners.

The liquid phase with yield value contains 0.5 to 10 wt .-% of an inorganic salt and 0.5 to 5 wt .-% of a co-surfactant selected from the group consisting of alkoxylated C ₈ -C ₁₈ fatty alcohols having a degree of alkoxylation ≤ 3, aliphatic C ₆ -C ₁₄ alcohols, aromatic C ₆ -C ₁₄ alcohols, aliphatic C ₆ -C ₁₂ dialcohols, monoglycerides of C ₁₂ -C ₁₈ fatty acids, diglycerol ethers of C ₈ -C ₁₈ fatty alcohols and mixtures it.

Among other things, in order to be able to ensure a sufficiently high concentration of surfactant contained in the liquid phase and other optionally contained ingredients and thus a sufficient washing, cleaning or care performance, the foam preferably contains 10 to 60% by volume of gas and 40 to 90% by volume. % Liquid phase. Particularly preferably, the foam contains 20 to 50% by volume of gas and 50 to 80% by volume of liquid phase. For example, a product containing less than 10% by volume of gas, and should be referred to as a discrete gas-bubble liquid product, does not have the benefit of improved adhesion to a soiled surface. In addition, the consumer does not recognize a product with less than 10% gas phase as a foam, and does not associate the appearance of a liquid product with discrete dispersed gas bubbles with delicacy, softness, protection, and care such as for a foam having a gas volume fraction of, for example, 20 % or even 40% is the case. Therefore, surfactant-containing foams having at least 10% by volume of gas are preferred. Foams containing more than 60% by volume of gas have such a low content of ingredients that can be washed, cleansed or cared for that the expected success of the treatment is unlikely to occur or at least can be expected to be questioned by the consumer , The consumer no longer perceives such a "dry foam" as wet foam, which can provide a satisfactory cleaning or care performance due to a high amount of cleaning and / or care agents. For these reasons, "dry foams" having less than 40% by volume of liquid phase are also not preferred embodiments of the present invention.

For the reasons set out above, the surfactant-containing foam preferably has a density of 400 to 900 g / l, in particular of 500 to 800 g / l.

It has been shown that with gas bubble sizes of 10 μm to 3 mm the best possible aesthetics can be achieved, which corresponds to the appearance of a surfactant-containing foam. With bubble sizes below 10 μm, a viewer can no longer recognize the bubbles as such with the naked eye. The perception then corresponds more to a homogeneous paste. With a bubble size of more than 3 mm, the product is again more like a liquid with individual gas bubbles than a foam, especially for smaller proportions of gas. In the surfactant-containing foam according to the invention gas bubble diameters from 50 microns are particularly preferred because the consumer can perceive correspondingly large bubbles very well as bubbles, with small bubbles this - especially from a distance - more difficult. It is also preferred that the gas bubbles have diameters below 1000 .mu.m, in particular below 800 .mu.m, since the stabilization of small bubbles is easier. To stabilize small bubbles, a lower yield strength of the liquid phase is required than to stabilize larger bubbles. Accordingly, to set the lower yield point, less thickener or less inorganic salt and optionally co-surfactant must be used to stabilize smaller gas bubbles compared to larger gas bubbles. Accordingly, the gas bubbles of the foam preferably have a diameter of from 10 μm to 3 mm, preferably from 20 to 1000 μm, more preferably from 50 to 800 μm and in particular from 100 to 500 μm.

Of particular advantage - both from an aesthetic point of view and from the perspective of stability - are surfactant-containing foams in which at least 70% of all foam bubbles have a size of 10 to 1000 .mu.m, in particular from 50 to 500 .mu.m (percentage on a numerical basis).

The gas bubbles of the surfactant-containing foam preferably contain a gas (mixture) comprising air, nitrogen and / or argon. In the context of this invention, the term "gas" also includes mixtures of several gases. Surprisingly, it has been found that the particle size distribution of the gas bubbles within a surfactant-containing foam over a period of 4 weeks and particularly narrow remains - so form bubbles to a lesser extent - if the gas bubbles of the surfactant-containing foam according to the invention additionally at least one other gas which is insoluble in the liquid phase.

In a further embodiment, the gas bubbles of the surfactant-containing foam preferably contain a gas mixture comprising air, nitrogen and / or argon and additionally at least one further gas comprising molecules having a molecular weight greater than 60. Also in this case, larger bubbles are formed in the surfactant-containing foam over time to a lesser extent. Preferably, these gases are insoluble in the liquid phase.

The gas which is insoluble in the liquid phase and / or which comprises molecules having a molecular weight greater than 60 may also be a vapor of a substance which is liquid at room temperature, since in the gas mixture a partial pressure of the insoluble gas which is marked is below atmospheric pressure, is sufficient. Of course, the gas phase of the surfactant-containing foam may also consist entirely of the insoluble gas.

Preferably, this gas is insoluble in the liquid phase and / or comprises molecules having a molecular weight greater than 60 selected from the group consisting of sulfur hexafluoride, perfluorocarbons, tetrafluoroethane, tetrafluoropropene, volatile siloxanes, volatile silanes, hydrocarbons, preferably highly branched iso-hydrocarbons, krypton, xenon and mixtures of these gases. Preferably, the gas is selected from the group consisting of sulfur hexafluoride, perfluorohexane, tetrafluoroethane, tetrafluoropropene, tetramethylsilane, hexamethyldisiloxane, octamethyltrisiloxane, cyclo-decamethylpentasiloxane and cyclo-octamethyltetrasiloxane, trimethylpentane, krypton, xenon, and mixtures of these gases.

The surfactant-containing foam can be further stabilized by the addition of solid particles, preferably hydrophobically modified silica particles and / or sparingly soluble surfactants. Without wishing to be bound by theory, the solid particles occupy and stiffen the surface of the gas bubbles, which contributes to further stabilization of the surfactant-containing foam. Accordingly, a surfactant-containing foam is particularly preferred in which the surfaces of the gas bubbles are coated with solid particles, in particular hydrophobically modified silica particles and particularly preferably with polydimethylsiloxane-functionalized silica particles. In this case, the proportion of solids particles relative to the liquid phase is preferably 0.05 to 5 wt .-%, preferably 0.1 to 2 wt .-%.

Other solid particles which may contribute to the stabilization of the surfactant-containing foam are preferably cationic particles. Cationic particles are understood to mean those which have a positive zeta potential under the relevant pH conditions. Methods for measuring the zeta potential of particles are known to the person skilled in the art. Without wishing to be bound by theory, anionic surfactant present on the cationic particles in the liquid phase adsorbs, which leads to a hydrophobicization and thus to an interfacial activity of the particles.

With particular preference is hydrotalcite, preferably used in a proportion based on the liquid phase of 0.1 to 2 wt .-%. Also suitable for stabilizing the surfactant-containing Foams are alumina particles. Accordingly, a surfactant-containing foam containing hydrotalcite particles and / or alumina particles is preferred.

Alternatively, it is possible to achieve further stabilization of the surfactant-containing foam by the presence of fatty alcohols having an alkyl chain of at least 14 carbon atoms in the liquid phase. Therefore, preferred is a surfactant-containing foam containing fatty alcohols with alkyl chains having at least 14 carbon atoms. N-fatty alcohols are preferably used here. Most preferably, the surfactant-containing foam contains n-fatty alcohols having 14 to 26 carbon atoms in the alkyl chain.
For reasons of stabilization, the surfactant-containing foam contains preferably 0.1 to 5% by weight, preferably 0.2 to 4 wt .-%, particularly preferably 0.3 to 3 wt .-% and in particular 0.4 to 2 wt .-% - based on the liquid phase - of one or more fatty alcohols (s) with alkyl chains having at least 14 carbon atoms, especially the fatty alcohols tetradecanol and / or hexadecanol. Of course, can be contained in these raw materials using technical grades and other C-chains.

Another possibility for long-term stabilization of surfactant-containing foams was found when using hydroxystearic acid. Preferably, the surfactant-containing foam contains hydroxystearic acid, preferably in an amount of 0.05 to 2 wt .-% and in particular in an amount of 0.1 to 1 wt .-% based on the liquid phase.

Another possibility for long-term stabilization of the foam is the addition of surfactants which are insoluble under the conditions of the liquid phase of the foam and are present in the form of particles or phase-separated droplets. An example of such a surfactant is octadecyl-pentaglycoside. Preferably, the surfactant-containing foam contains one or more surfactants which are insoluble under the conditions of the liquid phase of the foam and are in the form of particles or phase-separated droplets, more preferably the surfactant-containing foam contains octadecyl-pentaglycoside.

The pH of the surfactant-containing foam is preferably from 6 to 9 and especially from 7 to 8.

The surfactant-containing foam is preferably a washing or cleaning agent, especially a heavy duty detergent, a mild detergent, a hard surface cleaner, a toilet cleaner, a machine dishwashing detergent, or a hand dishwashing or a laundry treating agent.

Accordingly, the surfactant-containing foam preferably contains-in addition to the surfactant-further ingredients which further improve the performance and / or aesthetic properties of the washing or cleaning agent. In the context of the present invention, the surfactant-containing foam preferably additionally contains one or more substances from the group of builders, bleaches, enzymes, soil release polymers, electrolytes, pH adjusters, perfumes, perfume carriers, fluorescers, dyes, hydrotopes, silicone oils, antiredeposition agents, Complexing agents, graying inhibitors, anti-shrinkage agents, anti-wrinkling agents, color transfer inhibitors, antimicrobial agents, non-aqueous solvents, germicides, fungicides, antioxidants, preservatives, corrosion inhibitors, antistatic agents, acids, salts, bittering agents, ironing auxiliaries, repellents and impregnating agents, skincare active ingredients, swelling and anti-slipping agents , plasticizing components, bleach, bleach catalysts, and UV absorbers.

The surfactant-containing foam may contain anionic surfactants, nonionic surfactants, cationic surfactants, amphoteric surfactants or else mixtures of these surfactants. The surfactant contained in the liquid phase of the surfactant-containing foam is preferably selected from the group consisting of alkylpolyglycosides, betaines, alkoxylated, preferably ethoxylated or ethoxylated and propoxylated fatty acid alkyl esters, amine oxides, especially alkylamine oxides, alkyl sarcosinates and other amino acid-based headgroup surfactants , Polyhydroxy fatty acid amides, fatty acid amides, alkoxylated fatty acid amides, fatty acid ethanolamides, alkoxylated, advantageously ethoxylated, especially primary alcohols having preferably 8 to 18 carbon atoms and an average of 1 to 12 moles of ethylene oxide (EO) per mole of alcohol, alkylbenzenesulfonates, especially linear alkylbenzenesulfonates, olefinsulfonates, alkanesulfonates, Fatty alcohol sulfates, fatty alcohol ether sulfates, ester sulfonates, sulfonated fatty acid glycerol esters, salts of alkylsulfosuccinic acid, fatty acid soaps, alkylphenol polyglycol ethers, with monoethanolamine neutralisi erten alkylbenzenesulfonic acids, with monoethanolamine neutralized fatty acids and mixtures of these surfactants.

In one embodiment, the surfactant-containing foam is a detergent containing one or more components from the group of builders, chelants, perfumes, dyes, optical brighteners, bleaches and color transfer inhibitors.

In another embodiment, the surfactant-containing foam is a detergent containing lipase, mannanase and / or pectate lyase.

In another embodiment, the surfactant-containing foam is a detergent containing citric acid or citrate.

In a further embodiment, the surfactant-containing foam is a hard surface cleaner containing acid, fragrance and / or complexing agent.

In another embodiment, the surfactant-containing foam is a hard surface cleaner containing bleach, especially chlorine bleach.

In a further embodiment, the surfactant-containing foam is a hand dishwashing detergent containing perfume, salts and surfactant from the group formed by fatty alcohol sulfate, amine oxide, betaine, alkylpolyglycoside, fatty alcohol ether sulfate, linear alkylbenzenesulfonate, alkanesulfonate and mixtures thereof. Preferably, this foam contains 10 to 40 wt .-% surfactant.

In another embodiment, the surfactant-containing foam is a hard surface cleaner containing one or more components selected from the group consisting of corrosion inhibitors, chelants, bleaches, bleach catalysts, enzymes, polymers, builders, and mixtures thereof.

In a further embodiment, the surfactant-containing foam is a hard surface cleaner, which acid preferably contains sulfamic acid, hydrochloric acid, citric acid, lactic acid, formic acid and / or acetic acid, and preferably also corrosion inhibitors and / or polymers.

In another embodiment, the surfactant-containing foam is a cleaner for carpets containing bleach and solvent.

In a further embodiment, the surfactant-containing foam is a shampoo, a hair dye or a hair tint, a hair conditioner, a cleansing or care product for the human skin or a cleansing or care product for animal hair.

The surfactant-containing foam contains from 2 to 40% by weight of surfactant in the liquid phase. In preferred embodiments, the surfactant-containing foam is a detergent whose liquid phase contains at least 10% by weight, preferably at least 15% by weight, in particular at least 20% by weight of surfactant.

In another embodiment, the surfactant-containing foam is a hard surface cleaner whose liquid phase contains at most 15% by weight, preferably at most 10% by weight of surfactant.

The liquid phase of the surfactant-containing foam contains 20 to 98 wt .-%, preferably 25 to 85 wt .-% and in particular 30 to 70 wt .-% water. It represents a distinct advantage of the surfactant-containing foam over a conventional liquid or gel-like agent that in the surfactant-containing foam, the gas proportions of water contained in a comparable liquid or gel - with unchanged amount of surfactant and other active ingredients in the respective Liquid phases - can replace. For example, a certain volume of a liquid detergent contains 60% by volume of water, while the surfactant-containing foam with identical content of surfactant and other ingredients comprises only 30% by volume of water and also 30% by volume of gas. The foam is thus - based on the weight - concentrated and thus more efficient and economical or - based on the recipe - lighter and thus cheaper or more convenient to transport for the consumer. It is therefore a further advantage of the present invention that the water content of surfactant-containing agents can be lowered, which is undoubtedly of economic and ecological interest.

The surfactant-containing foam is preferably water-soluble or water-dispersible, with the exception of the gaseous constituents. If this is the case, it can be ensured that all constituents of the surfactant-containing foam, with the exception of the gaseous constituents, are available for cleaning / care of the treated surface.
As already defined by the definition of the surfactant-containing foam as a dispersed system of gas in a liquid phase, the present invention does not relate to foams having solid cell stems, which may also be insoluble or dispersible in water and thus act merely as a carrier similar to a sponge, the drug-containing preparations transported.

Preferably, the surfactant-containing foam is flowable or pourable, so that it can be dosed out of a storage bottle - pour out - leaves. The surfactant-containing foam itself preferably has a shear rate of 10 s ^-1 and a temperature of 20 ° C to a viscosity of 0.5 to 50 Pas. The viscosity of the surfactant-containing foam is determined with the same experimental set-up as described above for the viscosity of the liquid phase, but a cross-corrugated plate plate / plate measuring system is used to avoid "slipping" of the surfactant-containing foam ( Gap width 1500 μm).

In the presence of this viscosity, the dosage of a surfactant-containing foam from a deformable packaging, for example. A deformable plastic bottle is particularly well possible.

The preparation of the surfactant-containing foam is possible by means of methods known to the person skilled in the art. Preference is given to a process for the preparation of the surfactant-containing foam, in which a liquid phase containing surfactant is foamed by passing gas into the liquid phase, by passing the liquid phase through a gas or mechanically foaming.

The surfactant-containing liquid phase is particularly preferably foamed with a gas mixture comprising air, nitrogen and / or argon and preferably at least one further gas which has a molecular weight greater than 60 and which is preferably insoluble in the liquid phase.

In a particularly preferred embodiment, a dynamic foam generator with rotor-stator principle is used for foaming. Foam generators of this type make it possible to supply additional components via metering systems and to adjust the gas bubble size depending on the energy input. Depending on the design of the device, the amount to be continuously produced is between 1 kg / h and 5000 kg / h of foam. Since the gas can be chosen freely for foaming, it is possible with appropriate devices with little effort, gas mixtures, which for example comprise a gas which is insoluble in the liquid phase to use. Corresponding devices can be combined with test gas generator and gas mixing plant.

The liquid phase of the surfactant-containing foam is prepared by conventional methods and methods.

The present invention additionally provides a packaged product comprising a surfactant-containing foam whose liquid phase has a yield point.

The surfactant-containing foam is preferably packaged in such a way that the consumer can recognize the cell structure of the surfactant-containing foam without having to open the packaging for this purpose. Therefore, the material of the packaging is preferably transparent at least to a certain extent. For the purposes of this invention, transparency is to be understood as meaning that the permeability within the visible spectrum of the light (410 to 800 nm) is greater than 20%, preferably greater than 30%, very preferably greater than 40% and in particular greater than 50%. Thus, once a wavelength of the visible spectrum of the light has a transmittance greater than 20%, it is to be regarded as transparent within the meaning of the invention.

In one embodiment of the present invention, the packaged product comprising the surfactant-containing foam is a disposable portion, in particular a pouch, the envelope of which is preferably wholly or partly water-soluble and, with particular preference, transparent.

Suitable materials for the completely or partially water-soluble coating are in principle all materials in question, which can completely or partially dissolve in the aqueous phase under the given conditions of a washing process, rinsing or cleaning process (temperature, pH, concentration of detergent components). The polymer materials may particularly preferably belong to the groups (optionally partially acetalized) polyvinyl alcohol, polyvinylpyrrolidone, polyethylene oxide, gelatin, cellulose and derivatives thereof, starch and derivatives thereof, in particular modified starches, and mixtures (polymer blends, composites, coextrudates, etc.) of the materials mentioned. Particularly preferred are gelatin and polyvinyl alcohols and the two materials mentioned in each case in combination with starch or modified starch. There are also inorganic salts and mixtures thereof as materials for the at least partially water-soluble envelope in question.

If the wrapper or package of the surfactant-containing foam is transparent, the liquid phase of the surfactant-containing foam preferably contains a stabilizer which stabilizes the ingredients against degradation and deactivation phenomena by light irradiation. Antioxidants, UV absorbers and fluorescent dyes have proven to be particularly suitable here.

In addition, it is preferred if the surfactant-containing foam is only one phase of a multiphase agent. For example, pouches comprising a plurality of compartments, one or more of which contain a foam, possibly at least two foams of different colors, are particularly preferred. It is also possible to combine a surfactant-containing foam coated with a transparent film with a compressed tablet of a cast molded article.

Particularly preferred is a packaged product which is a container comprising multi-use surfactant-containing foam. This container preferably holds a volume of 20 to 2000 ml, in particular from 50 to 1000 ml.

This container is preferably a transparent container, in particular a transparent plastic or glass container, in particular a transparent glass or plastic bottle. The use of a glass container, for example a glass bottle, is preferred in particular for the cases in which the surfactant-containing foam is a cosmetic product, for example a shampoo or a bath additive.

If the container is a plastic bottle, then this can be deformed with particular preference, preferably so that its contents can be "pushed out".

The preferred subject of the present invention is a packaged product in the form of a transparent, preferably deformable plastic bottle comprising a surfactant-containing foam whose liquid phase has a yield point.

This bottle may have the spout / outlet valve above the reservoir or may also be designed such that the reservoir is located above the outlet valve of the dosing bottle (headstand bottle).

An example of a preferred packaged product is a transparent bottle in which two or three surfactant-containing foams of different colors are in marbled form.

It is also possible that the container comprising surfactant-containing foam is a tube for several applications.

Examples Example 1:

A detergent with the following composition was prepared: V1 E1 C _12-18 -ROH · 7EO 4 2 Na lauryl ether sulfate · 2EO 8th 8th C _12-18 fatty acid, sodium salt / C _12-18 fatty acid 1 1 Linear C _9-13 alkyl benzene sulfonic acid, sodium salt 4 4 Phosphonic acid, sodium salt 0.8 0.8 Optical brightener 0.1 0.1 Citric acid, sodium salt 2.5 2.5 sodium metaborate 1.1 1.1 ethanol 3 3 enzymes 1.8 1.8 Perfume 0.2 0.2 dye 0.001 0.001 NaCl 0 3 i -C ₁₃ -ROH · 3EO 0 4 water Ad 100 Ad 100 Yield point present No Yes All data in% by weight

The formulation E1 according to the invention was a lamellar phase and had a yield point. The comparative formulation V1 was an isotropic L1 phase without yield stress.

Both formulations were beaten with a laboratory foam generation device (rotor of a Sita Foam Tester R2000) to a flowable foam consisting of 60 volume% liquid phase and 40 volume% air.

The comparative formulation V1 separated within a few hours in a liquid phase and a water poorer foam phase. The formulation E1 according to the invention had no leakage of the foam and no separation of a liquid phase when stored at room temperature over a period of several weeks. Only an increase in bubble size was observed. However, the visual appearance of a single-phase foam was retained.

Example 2:

2% by weight of n- hexadecanol (formulation E2) were stirred into the formulation E1 according to the invention at 60 ° C. Then, at 50 to 60 ° C, the formulations E1 and E2 as described in Example 1 foamed to a foam of 60% by volume of liquid phase and 40% by volume of air.

The initial bubble size distribution of the foams was identical. Thereafter, the foams were cooled to room temperature and filled into cuvettes for photographing the bubble size. After 4 weeks of storage at 20 ° C, the foam of the formula E2 had a much narrower gas bubble size distribution than the foam of the formula E1.

Example 3:

• Beispiel 3.1: mit Luft entsprechend E1
• Beispiel 3.2: mit Luft, die zuvor durch eine Gaswaschflasche durchgeleitet wurde, welche bei Raumtemperatur flüssiges Perfluorhexan enthielt (E3). Der maximale Gehalt an Perfluorhexan des zum Schäumen verwendeten Gasgemisches entspricht somit dem Sättigungsdampfdruck des Perfluorhexans bei 20°).

The liquid formulation E 1 from Example 1 was foamed in two ways.

• Example 3.1: with air corresponding to E1
• Example 3.2: with air previously passed through a bubbler containing liquid perfluorohexane at room temperature (E3). The maximum content of perfluorohexane of the gas mixture used for foaming thus corresponds to the saturation vapor pressure of perfluorohexane at 20 °).

• Beispiel 3.1: In dem mit Luft aufgeschäumten Schaum weisen sämtliche Blasen einen Durchmesser kleiner 0,2 mm auf.
• Beispiel 3.2: In dem mit dem Luft-Perfluorhexan-Gemisch aufgeschäumten Schaum liegt mindestens 10 Volumen-% des im Schaum eingeschlossenen Gases in Form von Blasen mit einem Durchmesser zwischen 1 und 2 mm vor.

Both foams were stored for 9 weeks at 20 ° C.

• Example 3.1: In the foam foamed with air, all the bubbles have a diameter of less than 0.2 mm.
• Example 3.2: In the foam foamed with the air-perfluorohexane mixture, at least 10% by volume of the gas enclosed in the foam is in the form of bubbles with a diameter between 1 and 2 mm.

It could thus be observed that the foam E3 of Example 3.1 scarcely coarsened over 9 weeks, while the foam E1 of Example 3.2 exhibited a considerable enlargement of the gas bubbles in the same time.

Claims (12)

1. A surfactant-containing foam of which the liquid phase has a yield point, wherein

   - the yield point of the liquid phase is at least 0.1 Pa;

   - the liquid phase contains 2 to 40 wt.% surfactant;

   - the liquid phase contains 20 to 98 wt.% water;

   - the liquid phase having a yield point contains 0.5 to 10 wt.% of an inorganic salt and 0.5 to 5 wt.% of a co-surfactant selected from the group consisting of alkoxylated C₈-C₁₈ fatty alcohols having a degree of alkoxylation of ≤ 3, aliphatic C₆-C₁₄ alcohols, aromatic C₆-C₁₄ alcohols, aliphatic C₆-C₁₂ dialcohols, monoglycerides of C₁₂-C₁₈ fatty acids, monoglycerol ethers of C₈-C₁₈ fatty alcohols, and mixtures thereof.
2. The surfactant-containing foam according to claim 1, characterized in that the liquid phase per se has a viscosity of 0.1 to 50 Pas at a shear rate of 10 s^-1 and a temperature of 20 °C.
3. The surfactant-containing foam according to one of claims 1 or 2, characterized in that the liquid phase contains one or more thickeners and/or is in the form of a liquid-crystalline surfactant phase, preferably a lamellar surfactant phase.
4. The surfactant-containing foam according to one of claims 1 to 3, characterized in that the foam contains 10 to 60 vol.% gas and 40 to 90 vol.% liquid phase.
5. The surfactant-containing foam according to one of claims 1 to 4, characterized in that the gas bubbles of the foam have a diameter of 10 µm to 3 mm.
6. The surfactant-containing foam according to one of claims 1 to 5, characterized in that the surfaces of the gas bubbles are coated with solid particles, in particular hydrophobically modified silica particles, in particular with polydimethylsiloxane-functionalized silica particles and/or the foam contains fatty alcohols having alkyl chains having at least 14 carbon atoms, in particular hexadecanol, and/or contains hydroxystearic acid and/or contains hydrotalcite and/or contains alumina and/or contains surfactants which are insoluble under the conditions of the liquid phase of the foam and are in the form of particles or phase-separated droplets.
7. The surfactant-containing foam according to one of claims 1 to 6, characterized in that it is a washing or cleaning agent, in particular a heavy duty detergent, a mild detergent, a cleaner for hard surfaces, a toilet cleaner, a cleaner for automatic dishwashing or dishwashing by hand or a treating agent for laundry.
8. The surfactant-containing foam according to one of claims 1 to 7, characterized in that the foam, with the exception of the gaseous constituents, is water-soluble or water-dispersible.
9. The surfactant-containing foam according to one of claims 1 to 8, characterized in that the foam has a viscosity of 0.5 to 50 Pas at a shear rate of 10 s^-1 and a temperature of 20 °C.
10. A method for preparing a surfactant-containing foam according to one of claims 1 to 9, in which a surfactant-containing liquid phase is foamed by introducing gas into the liquid phase, by passing the liquid phase through a gas or mechanically.
11. A packaged product comprising a surfactant-containing foam according to one of claims 1 to 19.
12. The packaged product according to claim 11, characterized in that it is a container comprising surfactant-containing foam for a plurality of applications, in particular a transparent container and in particular a transparent plastic bottle.