MXPA06009212A - Composition and method - Google Patents

Abstract

A cleaning composition comprising from 30 to 70 percent by weight of 1-alkyl-2-pyrrolidone, from 25 to 45 percent by weight of hydrocarbon and from 5 to 25 percent by weight of water exhibits good cleaning performance and a visual indication ofactivity. The composition is on or adjacent to a phase boundary of its phase diagram and exhibits self-induced surface motility of the Marangoni type.

Description

COMPOSITION AND METHOD FIELD OF THE INVENTION The present invention relates to the field of cleaning. It particularly relates to a cleaning composition and a cleaning method.

BACKGROUND OF THE INVENTION EP-A-330379 discloses the use of cleaning compositions containing at least one alcohol ether, water and a hydrocarbon in a single phase, respectively in ratios of 90-50% by weight: 2-36 : 25-0.9. It is said that the composition is suitable for removing the adherent oil from surfaces e. g. Rock cuttings produced during oil drilling operations. The compositions are prepared by simply mixing the chemicals, stirring manually, and subsequently allowing the mixture to separate into three phases. The intermediate phase was the cleaning composition, and it was extracted and used for cleaning tests. This intermediate phase contained alcohol ether in a greater proportion, and smaller amounts of water and hydrocarbon. A disadvantage of this system is the large amount of alcohol ether present in the cleaning composition. The use of large quantities of many alcohol ethers is now regulated by legislation regarding VOCs (Volatile Organic Compounds). There is a need for cleaning compositions, with reduced levels of volatile compounds, that clean surfaces, particularly hard surfaces in an effective manner. There is also a need for cleaning compositions that provide a visual indication to the user working with them.

SUMMARY OF THE INVENTION According to a first aspect of the present invention there is provided a cleaning composition comprising 30 to 70 weight percent of l-alkyl-2-pyrrolidone, 25 to 45 weight percent of hydrocarbon and to 25 weight percent water. The composition may be in the form of a single phase or may be present as two or three phases in mutual chemical equilibrium. In cases where the composition is in a single phase, it has the advantage that it does not need to be mixed or stirred before being used. In cases where the composition is in the form of 2 or 3 phases, the visual cleaning indication due to the mobility of the system is more visible. In this case, the composition is preferably stirred or mixed immediately before use. Preferably the composition is adjacent to a phase boundary in the three component phase diagram for the composition. Therefore, it should be understood that a change in relation to the percentages by weight of the three components of the composition caused by the loss of only one component, whereby the percentage by weight of that component is reduced by an absolute value of 1% or less, preferably 0.5% or less, more preferably 0.1% or less (expressed as weight percentage of the total weight of the total composition), leads to a change in the number of phases present in the composition, for example changing from a single phase to a mixture of 2 or 3 phases. In this description when a percentage value is given for a component, it denotes the percentage by weight of that component, based on the total weight of the composition of which the component is part.

BRIEF DESCRIPTION OF THE FIGURES Figure 1 shows the phase diagram for the 1- (n-octyl) -2-pyrrolidone / n-dodecane / water system.

DETAILED DESCRIPTION OF THE INVENTION The compositions of the present invention comprise l-alkyl-2-pyrrolidone. Preferably, the alkyl group has on average 4 to 16 carbon atoms, more preferably 6 to 14 carbon atoms, and more preferably 8 to 12 carbon atoms. Preferably, the alkyl group is linear. The 1-octyl 2-pyrrolidone is particularly suitable. The essential hydrocarbon to the compositions of the invention is conveniently a paraffinic compound, including isoparaffinic compounds. The hydrocarbon may conveniently be a hydrocarbon fragrance. Preferably it is a liquid under ambient conditions. Preferably the hydrocarbon has 5 or more carbon atoms, more preferably 8 or more. Preferably the hydrocarbon has up to 15 carbon atoms, more preferably up to 12 carbon atoms. When the hydrocarbon is a mixture, as will often be the case, these definitions still apply, as average values. When a hydrocarbon is present it tends to be lighter than any other phase, and at certain levels of hydrocarbon it can be separated. Preferably a hydrocarbon present is significantly more volatile than water or amphiphile.By volatile it is understood that a material has a vapor pressure of 0.2 mm Hg or greater at 20 ° C. In this description when a hydrocarbon is mentioned it should be understood that there may be more than one such hydrocarbon present. The definitions of percentage by weight denote the total complement of the hydrocarbon compounds present. The compositions of the invention conveniently have from 30 to 70 weight percent of l-alkyl-2-pyrrolidone, preferably from 40 to 60 percent, more preferably from 45 to 55 percent. Conveniently, the compositions of the invention comprise from 25 to 45 percent by weight of the hydrocarbon, preferably from 30 to 40 percent, more preferably from 33 to 37 percent. Conveniently, the compositions of the invention comprise from 5 to 25% by weight of water, preferably from 10 to 20%. Conveniently the composition may contain an electrolyte, preferably an ionic salt. Suitable examples include alkali metal salts, especially halides. The most preferred, for reasons that include cost and safety, is sodium chloride. An electrolyte can be used to alter the phase diagram by changing the boundaries of the phases such that the composition is at or adjacent to a phase boundary, as is preferred according to the first aspect of the present invention. When an electrolyte is present, it is included with the water, treating the water and electrolyte as a single component for the purpose of drawing a three-component phase diagram. It is highly preferred for the compositions of the invention to include a fragrance in order to make the aroma of the compositions more palatable in a household cleaning composition. Preferably at least 0.1% by weight of the fragrance is present, more preferably 0.4% or more, but preferably 1% or less, more preferably 0.8% or less. The fragrance is included with the hydrocarbon for the purpose of drawing a phase diagram of three components of the composition. Fragrance is fragrance oil without any base or diluent included. The compositions of the present invention may include low levels, preferably less than 1% by weight of the composition, of conventional auxiliaries used in household cleaning products, provided that these do not have a substantial effect on the behavior of the household phase. composition. In terms of plotting a three-component phase diagram for the system, the skilled person would assign such components to be included with the water, amphiphile or hydrocarbon at the corner of the phase diagram based on the Hansen solubility parameter for the component. The surfactant, which is a preferred ingredient, at a percentage weight of the composition of 0.01 to 0.1%, more preferably 0.03 to 0.05%, is included with the amphiphile in the phase diagram. The nonionic surfactant, such as alcohol ethoxylate, is particularly preferred when the surfactant is present. Biostatic agents such as cationic biostatic agents or conveniently PCMX (parachlorometaxyleneol) can also be incorporated into the compositions of the invention. Bleaching systems such as peroxide-based bleaches can also be used in the compositions of the invention. Extraordinarily, it has been found that the compositions of the invention can apparently exhibit arangoni-like behavior. When a container of a preferred composition of the invention is opened and exposed to the environment it can be observed that the surface "contracts". This effect is believed to be due to surface tension gradients, perhaps convex at the crossing of phase boundaries, when the volatile compounds evaporate. Such compositions have been observed in which, when the container is recapped, the "shrinkage" is stopped. The "contraction" can occur if the composition is pipetted on the surface. By "contraction" it is meant that the surface of the composition showed mobility not induced by an external agent, such as an object applied to it.; in other words a self-induced mobility. According to a second aspect of the present invention there is provided a cleaning composition which includes water, a hydrocarbon and l-alkyl-2-pyrrolidone as defined above, which composition exhibits a Marangoni behavior when exposed to air. Preferably, the composition exhibits a Marangoni behavior only when exposed to air. Preferably, the composition is in the form of 2 or 3 phases in mutual equilibrium before being exposed to air. For the purposes of this description, the Marangoni effect can be defined as the effect on a liquid when the surface tension gradients cause the movement of the liquid. Surface tension gradients may result from changes in concentration (Gibbs effect), which may occur from evaporation, or from improper mixing, followed by separation or segregation in a container, or by application of a tension, for example a cutting force (as by a cleaning action). Without wishing to be bound by theory, it is considered that the Marangoni effect can give rise to cleaning benefits shown by the compositions of the invention. Compositions that show the Marangoni effect may show a tendency to "slide" into small spaces. The evaporation of a compound can lead to changes in surface tension and surface mobility, causing the composition to move, for example to and then out of a crack, dragging spots with it. The use of amphiphiles such as 1-alkyl-2-pyrrolidone can aid in the removal of dirt from a substrate. Amphiphiles generally do not promote adhesion with a surface but can humidify well. Thus compositions containing an amphiphile that show the Marangoni effect can move towards small interstices or can move between a surface and a stain deposit, "lifting" the latter. According to a third aspect of the present invention there is provided a method of cleaning a stained substrate, comprising applying to the stained substrate a composition of the first and / or second aspect of the present invention, as defined above. Another aspect of the invention is the use of the compositions as described above for cleaning domestic substrate. Another aspect of the invention is to provide a packaged household cleaning composition, wherein the cleaning composition is a composition as described above for the other aspects of the invention. The substrate can be, for example, a hard surface, for example, a surface in the kitchen or bathroom, including a work surface, floor, tile, glass, object of sanitary use, windows, crockery pieces or a domestic device; or a cloth surface, for example, an article of clothing or upholstery. The stain on the substrate can, for example, be grease, a protein stain, wine, fruit juice or makeup. Preferred compositions of the present invention are provided in containers having a manually operated pump such as a "trigger sprayer", or in containers from which the contents are poured or expressed by squeezing the container or in aerosol dispensers. In aerosol dispensers the hydrocarbon in the composition may be the same as the propellant and the evaporation of the propellant by itself could induce a Marangoni effect. Containers containing ready-to-use compositions of the invention constitute another aspect of the present invention, notably containers adapted to deliver such compositions directly to hard surfaces (eg aerosols and "trigger sprinklers"). Containers containing dilute, aqueous compositions (i.e. comprising the components of the composition without water, being the water added by the user of the product before using it) constitute an additional aspect. This provides the advantage of reduced packaging and transportation costs. The invention will now be described, by way of example, with reference to the following example. Figure 1 shows the phase diagram for a system of interest of this invention, 1- (n-octyl) -2-pyrrolidone / n-dodecane / water. It will be appreciated that this phase diagram also shows phase changes in the water rich corner, moving from two phases, (1- (n-octyl) -2-pyrrolidone / water) to three phases, to two phases (n-dodecane) / Water) . Small changes in the composition, for example induced by the preferential evaporation of a component, probably cause the composition to cross a phase boundary again. It is considered that this is important in this system in obtaining a "contraction" effect. An appropriate formulation of the invention showing cleaning and mobility has 50% by weight of l-n-octyl-2-pyrrolidone, 15% by weight of water and 35% by weight of n-dodecane.

Claims (7)

1. NOVELTY OF THE INVENTION Having described the invention as above, the content is claimed as contained in the following: CLAIMS 1. A cleaning composition characterized in that it comprises from 30 to 70 weight percent of l-alkyl-2-pyrrolidone, from 25 to 45 percent by weight. hydrocarbon weight and from 5 to 25 weight percent water.
2. 2. A cleaning composition according to claim 1, characterized in that the water, the 1-alkyl-2-pyrrolidone and the hydrocarbon coexist as a single phase without separating from each other as layers.
3. 3. A cleaning composition according to claim 1 or claim 2, characterized in that the l-alkyl-2-pyrrolidone is l-n-octyl-2-pyrrolidone.
4. 4. A cleaning composition, characterized in that it comprises water, a hydrocarbon and an l-alkyl-2-pyrrolidone, the composition shows a Marangoni behavior when exposed to air.
5. A method for cleaning a stained substrate, characterized in that it comprises applying to the stained substrate a composition according to any of the preceding claims.
6. 6. The use of a composition according to any of claims 1 to 4 for cleaning household substrates.
7. 7. A household cleaning product, packaged, characterized in that it comprises a composition according to any of claims 1 to.