Sprayable composition and method for temporarily preserving water-based paint during painting interruptions

Abstract

A method is provided for inhibiting drying of a water-based paint during a temporary interruption in painting. A sprayable preservation composition is applied to an exposed surface of the paint, whereupon the composition spreads to form a surface layer comprising one or more components having an evaporation rate lower than that of water. The surface layer reduces evaporative mass transfer of water from the paint to ambient air, thereby delaying drying of the paint. When painting resumes, the composition may be mixed into the paint so that it redistributes within the paint. Sprayable preservation compositions suitable for use in the method may include glycol-based formulations or water-based formulations containing surface-active additives. The arrangements allow exposed paint to remain workable during interruptions in painting activity.

Description

Sprayable Composition and Method for Temporarily Preserving Water-Based Paint During Painting Interruptions Field of the Invention

[0001] This disclosure relates generally to paint preservation techniques. More particularly, the disclosure relates to sprayable compositions and associated methods for temporarily inhibiting drying of water-based paints during interruptions in painting operations by suppressing evaporative loss of water from exposed paint surfaces.Background of the Invention

[0002] Water-based paints, including acrylic latex paints and other aqueous coating systems, are widely used in architectural, decorative and industrial painting applications. Such paints typically comprise an aqueous carrier phase, polymeric binder particles dispersed within the aqueous phase, pigments for colour and opacity, and various additives that control properties such as viscosity, dispersion stability, film formation and drying behaviour. When applied to a substrate, the drying of these paints generally occurs through evaporation of water from the applied paint layer, followed by coalescence of binder particles to form a continuous film.

[0003] During painting operations, paint is frequently stored in open containers or painting implements such as trays, rollers or brushes while work is in progress. In such situations, portions of the paint may remain exposed to ambient air for extended periods of time. Under typical environmental conditions, water evaporation from the exposed paint surface may lead to thickening of the paint, changes in rheological properties, or the formation of partially dried material at the paint surface. These effects may become more pronounced where painting activities are interrupted for periods of time.

[0004] Various approaches have been proposed for influencing the drying behaviour of paints or related coating compositions. Some approaches involve modification of the coating formulation itself by introducing additives intended to influence drying characteristics or application properties.

[0005] One example is described in a product referred to as “Professional Palette Wetting Spray”, available from Liquitex and retrieved from the internet on 20 June 2025 (https: / / www.liquitex.com / en-row / collections / professional-mediums-fluid-mediums / products / professional-palette-wetting-spray) [hereinafter referred to as D1], This product is described as a spray used with acrylic paints to maintain the workability of paint during artistic painting activities. The product is applied by spraying a mist over acrylic paint located on an artist’s palette or over a painted surface. The product is described as helping to keep the paint workable for longer periods of time. In use, the spray is applied periodically to paint present on the palette while painting is in progress.

[0006] Other prior art documents describe coating compositions that incorporate specific additives intended to influence application properties of aqueous paints.

[0007] For example, GB 2298427 A (ROHM & HAAS COMPANY) published 4 September 1996 [hereinafter referred to as D2] describes aqueous coating formulations that include polyurethane dispersions and other components incorporated into the coating composition. The document describes formulations comprising aqueous latex binders together with additional polymeric dispersions that may influence properties such as open time and application behaviour of the coating. The additives described in this document are incorporated into the coating formulation itself and are present as part of the paint composition when the coating is applied to a substrate.

[0008] Another example is WO 2010 / 027487 A1 (EASTMAN CHEMICAL COMPANY) published 11 March 2010 [hereinafter referred to as D3], This document describes coating compositions containing specific combinations of polymeric materials and coalescing agents. The formulations disclosed include components such as water-dispersible polymers, plasticisers and cyclohexanedimethanol compounds. These materials are incorporated into aqueous coating formulations and may influence characteristics such as open time and film formation during coating application.

[0009] Similarly, WO 2003 / 082999 A1 (AVECIA BV et al.) published 9 October 2003 [hereinafter referred to as D4] describes aqueous coating compositions containingdispersed polymer systems and additional oligomeric components. The formulations disclosed in this document include combinations of polymer dispersions, oligomeric compounds and co-solvents. These compositions are intended to influence the drying behaviour and application characteristics of the coating once applied to a substrate.

[0010] The documents described above therefore disclose various approaches in which additives or additional components are incorporated directly into coating formulations in order to influence coating properties during application and drying. In many cases, these additives are present within the coating composition itself prior to application to a surface.

[0011] Notwithstanding these developments, challenges may still arise in situations where paint remains exposed to ambient air during interruptions in painting activities. In such circumstances, the exposed paint may continue to undergo evaporation and other drying processes while the painting operation is temporarily paused.

[0012] It is to be understood that, if any prior art information is referred to herein, such reference does not constitute an admission that the information forms part of the common general knowledge in the art, in Australia or any other country.Summary of the Disclosure

[0013] According to one aspect there is provided a method of inhibiting drying of a water-based paint during a temporary interruption in painting. The method comprises applying a sprayable preservation composition onto an exposed surface of the waterbased paint and allowing the composition to spread across the exposed paint surface to form a surface layer comprising one or more components having an evaporation rate lower than that of water. The surface layer reduces evaporative mass transfer of water from the exposed paint to ambient air and thereby delays drying of the paint. Upon resumption of painting, the preservation composition may be mixed into the water-based paint such that the composition redistributes within the paint.

[0014] The method operates by modifying the physical conditions at the paint-air interface during a period in which painting activity is temporarily interrupted. When the preservation composition is applied to the exposed paint surface, the composition spreads to form a surface layer enriched with components that evaporate more slowlythan water. The resulting layer alters the interfacial environment between the paint and the surrounding air and reduces the rate at which water vapour escapes from the paint. By suppressing evaporative mass transfer of water, the onset of drying phenomena such as thickening or surface skin formation may be delayed.

[0015] This mechanism differs from a number of prior art approaches that influence drying behaviour using different technical mechanisms.

[0016] For example, prior art D1 describes a spray applied to acrylic paint on an artist’s palette in order to keep the paint workable during painting. The spray operates primarily by wetting the paint surface and replenishing moisture within the surface region of the paint so as to maintain workability of the acrylic paint during artistic painting activities.

[0017] Prior art D2 describes aqueous coating formulations in which additional polymer dispersions are incorporated directly into the coating composition. These polymeric components form part of the coating formulation itself and influence properties such as open time and application behaviour when the coating is applied to a substrate.

[0018] Similarly, D3 discloses aqueous coating formulations containing combinations of polymeric materials, plasticisers and coalescing agents that are incorporated into the coating composition. These materials influence the behaviour of the coating formulation during application and film formation.

[0019] D4 also relates to aqueous coating compositions that include dispersed polymer systems together with oligomeric components and co-solvents. These components are included within the coating formulation and influence the drying behaviour and film formation characteristics of the coating once applied to a surface.

[0020] The approaches described in D1-D4 therefore operate either by rehydrating exposed paint or by modifying the internal formulation of a coating composition through the inclusion of additional polymeric or additive components within the paint formulation itself.

[0021] In contrast, the present method relies on the formation of a surface layer containing relatively low-volatility components that suppress evaporation from theunderlying paint. The preservation composition establishes a transient interfacial layer that modifies the mass transfer conditions at the paint surface during the interruption period. By altering the evaporation dynamics at the exposed paint surface rather than modifying the internal formulation of the paint, the method allows exposed paint to remain workable during temporary interruptions in painting operations.

[0022] In certain embodiments, the preservation composition may comprise one or more hygroscopic components capable of retaining moisture at the exposed paint surface. Such components may attract or retain water molecules within the surface region of the paint, which may further assist in reducing the rate of evaporative water loss during the interruption period.

[0023] In some arrangements, the preservation composition may include one or more glycol compounds having vapour pressures lower than that of water at ambient temperature. Glycols may exhibit relatively low volatility and may therefore remain present at the paint-air interface for extended periods following application. The presence of such compounds within the surface layer may assist in maintaining a moisture-rich interfacial environment that slows evaporation from the underlying paint.

[0024] In certain embodiments, the preservation composition may comprise a carrier phase capable of spreading across the exposed paint surface. The carrier phase may allow sprayed droplets of the composition to coalesce and distribute across the paint surface to form a relatively continuous surface layer. Improved spreading behaviour may enhance the ability of the composition to suppress evaporative mass transfer across the exposed paint surface.

[0025] In some implementations, the preservation composition may be delivered in the form of a spray. For example, the composition may be dispensed from an aerosol container or other pressurised spray device. Spray delivery may allow the composition to be rapidly and uniformly distributed across exposed paint surfaces without requiring direct contact with the paint.

[0026] According to certain embodiments, the preservation composition may comprise one or more glycol-based components. For example, the composition may includepropylene glycol. Propylene glycol is a hygroscopic material with relatively low volatility and may therefore contribute to the formation of a surface region enriched with components that evaporate more slowly than water.

[0027] In certain implementations, the preservation composition may further comprise propylene glycol methyl acetate. The presence of such a co-solvent may influence the wetting characteristics, spreading behaviour and compatibility of the composition with water-based paint systems. In some embodiments, the composition may comprise a mixture including propylene glycol and propylene glycol methyl acetate.

[0028] In certain preferred embodiments, the relative proportions of propylene glycol and propylene glycol methyl acetate may be selected to provide a formulation capable of forming an effective evaporation-suppressing surface layer while remaining compatible with the paint. For example, the composition may include a majority proportion of propylene glycol together with a smaller proportion of propylene glycol methyl acetate.

[0029] In other embodiments, the preservation composition may include water together with one or more surface-active additives. The presence of water may assist in maintaining compatibility with water-based paint systems, while surface-active additives may influence wetting and spreading characteristics of the sprayed composition.

[0030] In certain implementations, the preservation composition may comprise a formulation including water, a surface-active additive marketed as LPG 26038 by BYK, and propylene glycol methyl acetate. Such formulations may provide favourable spreading characteristics across exposed paint surfaces and may contribute to the formation of a surface layer capable of suppressing evaporative loss of water from the paint.

[0031] In some embodiments, the relative proportions of the components in the formulation may be selected to provide effective evaporation suppression while maintaining compatibility with water-based paint systems. For example, the formulation may include water as a principal component together with smaller quantities of LPG 26038 and propylene glycol methyl acetate.

[0032] In certain implementations, the preservation composition may be formulated so as to be substantially free of pigment particles. The absence of pigments may reduce the likelihood that the preservation composition will influence the colour characteristics of the paint once the composition is mixed back into the paint.

[0033] In some embodiments, the preservation composition may also be substantially free of curing agents or crosslinking agents. This may reduce the likelihood that the preservation composition will influence the curing behaviour of the paint once it is applied to a substrate.

[0034] In certain arrangements, the preservation composition may redistribute within the paint following agitation of the paint after the interruption period. Such redistribution may allow the paint to return to a substantially homogeneous condition suitable for continued application.

[0035] According to another aspect, there is provided a sprayable paint preservation composition comprising one or more low-volatility components having an evaporation rate lower than that of water, wherein when used by applying the composition onto an exposed surface of a water-based paint the composition spreads across the paint surface to form a surface layer that reduces evaporative mass transfer of water from the paint to ambient air and thereby delays drying of the paint.

[0036] In certain embodiments of this aspect, the composition may include hygroscopic components capable of retaining moisture at the paint surface. Such components may assist in maintaining a moisture-rich interfacial environment and may contribute to suppression of evaporative water loss.

[0037] In some implementations, the composition may include propylene glycol and propylene glycol methyl acetate. These materials may cooperate to provide a formulation exhibiting favourable wetting behaviour, low volatility and compatibility with water-based paint systems.

[0038] In certain embodiments, the composition may comprise a majority proportion of propylene glycol together with a smaller proportion of propylene glycol methyl acetate. Such proportions may provide an effective balance between evaporation suppression and spreading characteristics.

[0039] In other embodiments, the composition may comprise water together with LPG 26038 and propylene glycol methyl acetate. The presence of the surface-active additive may promote spreading of the composition across the paint surface, thereby assisting in the formation of a surface layer capable of suppressing evaporative water loss.

[0040] In certain implementations, the composition may comprise approximately eighty percent water, approximately sixteen percent LPG 26038, and approximately four percent propylene glycol methyl acetate, although variations in these proportions may be employed while still achieving the evaporation-suppressing behaviour described above.

[0041] Other aspects of the invention are also disclosed.Description of Embodiments

[0042] There is provided a method for inhibiting drying of a water-based paint during a temporary interruption in painting. Water-based paints, such as acrylic latex paints commonly used in architectural and decorative applications, rely primarily on evaporation of water as the principal drying mechanism. During application, paint is typically held in open environments such as trays, rollers, brushes or containers where a relatively large surface area of the paint is exposed to ambient air. Under such conditions, water evaporates from the exposed paint surface, leading to an increase in solids concentration within the surface region of the paint. This process may result in increased viscosity, partial skin formation, coagulation of binder particles, or initiation of film formation at the surface. Once this occurs, the paint may become difficult to apply uniformly and may no longer provide a consistent coating when application resumes.

[0043] A sprayable preservation composition is applied onto an exposed surface of a water-based paint. The composition is delivered in spray form so that it can be evenly distributed across the exposed paint surface without requiring physical agitation or mixing at the time of application. The spraying action facilitates the formation of a relatively thin and uniform layer over the exposed paint surface. This layer may spread across the paint surface due to surface tension effects and wetting behaviourof the sprayed composition. The sprayable nature of the composition therefore enables rapid treatment of exposed paint during an interruption in painting activity.

[0044] Following application, the preservation composition spreads across the exposed paint surface and forms a surface layer comprising one or more components having an evaporation rate lower than that of water. In practical implementations, these components may comprise low-volatility liquids or humectant-type compounds that remain substantially at the surface of the paint during the interruption period. Because these components evaporate more slowly than water, the resulting surface layer alters the mass transfer conditions at the interface between the paint and the surrounding air.

[0045] In particular, the surface layer acts to reduce evaporative mass transfer of water from the exposed paint to ambient air. The presence of the layer introduces a phase at the paint-air interface having lower vapour pressure and reduced volatility relative to the underlying aqueous paint. As a result, the rate at which water molecules escape from the paint into the surrounding atmosphere is reduced. By slowing this evaporation process, the onset of drying phenomena such as skin formation, thickening, or coagulation of paint components can be delayed.

[0046] The formation of this surface layer therefore provides a technical mechanism for temporarily stabilising the exposed paint during a pause in application. The preservation composition effectively modifies the interfacial conditions at the paint surface rather than altering the internal formulation of the paint itself. In this manner, the method allows the exposed paint to remain in a workable condition for a longer period of time than would otherwise occur in the absence of the preservation composition.

[0047] When painting is resumed, the preservation composition is mixed into the water-based paint such that the composition redistributes within the paint. Mixing may occur through conventional agitation practices used by painters, such as stirring the paint in a tray, rolling a paint roller within the tray, or agitating the paint in a container. Because the preservation composition is formulated to be compatible with water-based paint systems, it can be re-dispersed into the paint without forming separate phases or residues.

[0048] Following mixing, the paint returns to a substantially homogeneous condition and remains suitable for application to a substrate. In many practical implementations, the preservation composition may be present in the paint at relatively low concentrations following mixing, such that the original handling characteristics of the paint are substantially maintained. The method therefore enables temporary preservation of the paint during an interruption while allowing normal painting operations to continue once the interruption has ended.

[0049] An advantage of this method is that it allows paint that would otherwise dry or form a surface skin during an interruption to remain usable without requiring sealing of containers, wrapping of painting tools, or disposal of partially dried paint. By acting directly at the exposed paint surface, the preservation composition provides a practical and efficient means of temporarily inhibiting drying while maintaining compatibility with the original paint formulation.Hygroscopic Components and Low-Volatility Compounds

[0050] In certain embodiments, the preservation composition may comprise one or more hygroscopic components configured to retain moisture at the exposed paint surface. Hygroscopic compounds are capable of attracting and retaining water molecules from surrounding media. When present within the preservation composition, such compounds may assist in maintaining moisture in the vicinity of the paint-air interface, thereby reducing the rate at which water evaporates from the exposed paint surface.

[0051] Suitable hygroscopic components may include one or more glycol compounds. Glycols are commonly used in aqueous formulations due to their water miscibility, relatively low volatility, and moisture-retention characteristics. Examples of suitable compounds may include propylene glycol, ethylene glycol, dipropylene glycol, glycerol, or similar polyhydric alcohols. Preferably, the selected compounds possess vapour pressures lower than that of water at ambient temperature so that they remainpredominantly within the surface region formed on the paint rather than rapidly evaporating into the surrounding atmosphere.

[0052] The presence of such hygroscopic and relatively low-volatility compounds within the preservation composition may contribute to the formation of a surface region enriched with components that evaporate more slowly than water. In practice, when the composition is sprayed onto the exposed paint surface, these components may accumulate within the surface layer and remain there during the interruption period. The resulting layer may exhibit reduced evaporation rates relative to the underlying aqueous paint phase.

[0053] This behaviour may suppress the diffusion of water vapour from the paint to the surrounding atmosphere. By slowing the rate of water loss, the exposed paint may remain in a workable condition for a longer period of time before noticeable thickening or surface skin formation occurs. Such an effect may be particularly beneficial in environments where evaporation rates are elevated, such as in warm or low-humidity conditions.Surface Spreading Behaviour

[0054] In certain embodiments, the preservation composition may comprise a carrier phase that spreads across the exposed paint surface to form the surface layer described above. The carrier phase may include liquids having surface tension and wetting properties that allow sprayed droplets to coalesce and distribute across the exposed paint surface.

[0055] When the composition is applied as a spray, droplets of the preservation composition may deposit across the paint surface and subsequently merge or spread due to surface energy interactions. This spreading behaviour may assist in forming a relatively continuous layer across the exposed paint surface. A more continuous surface layer may provide improved suppression of evaporative mass transfer compared with isolated droplets or discontinuous patches of liquid.

[0056] The carrier phase may comprise water-miscible solvents or other liquid components capable of wetting and spreading across aqueous paint surfaces. Preferably, these components are compatible with the underlying water-based paintformulation so that the preservation composition may subsequently be re-dispersed into the paint during mixing when painting resumes.

[0057] Through the combined effects of hygroscopic moisture retention, low volatility of selected components, and spreading behaviour across the paint surface, the preservation composition may create a transient interfacial environment that slows evaporation from the exposed paint. This may extend the time during which the paint remains workable during an interruption in painting activities while still allowing the composition to be later mixed back into the paint without adversely affecting subsequent application.Aerosol Delivery of the Preservation Composition

[0058] In certain embodiments, the preservation composition may be delivered as an aerosol spray. Aerosol delivery provides a convenient and effective mechanism for distributing the preservation composition across an exposed paint surface in a relatively uniform manner. The use of an aerosol spray may allow the composition to be applied quickly and evenly over the exposed paint without requiring physical contact with the paint surface.

[0059] The aerosol spray may generate fine droplets of the preservation composition which deposit across the exposed paint surface. These droplets may subsequently spread and coalesce due to the wetting characteristics of the composition, thereby assisting in the formation of the surface layer previously described. The fine droplet size produced by aerosol atomisation may also assist in achieving relatively uniform coverage of irregular paint surfaces such as those present on rollers, brushes, trays or other painting implements.

[0060] Aerosol delivery systems may utilise conventional pressurised containers in combination with propellant systems suitable for dispersing liquid compositions. Suitable propellants may include, for example, dimethyl ether, propane, butane, isobutane, or mixtures thereof. In some embodiments, compressed gas propellants such as nitrogen or carbon dioxide may alternatively be employed. The selected propellant may be chosen so as to be compatible with the preservation composition and capable of producing an appropriate spray pattern and droplet size.

[0061] The use of aerosol packaging may provide several practical advantages. The composition may be stored in a sealed container which protects the formulation from contamination and evaporation during storage. The spray delivery system may also allow the composition to be applied in controlled quantities, thereby reducing the likelihood of excessive application that might otherwise dilute the paint.

[0062] In certain implementations, the aerosol container may be equipped with a spray nozzle configured to produce a fan-shaped or conical spray pattern. Such spray patterns may assist in covering relatively large exposed paint surfaces, such as the surface of paint in a tray, with a single pass of the spray.Glycol-Based Preservation Compositions

[0063] In certain embodiments, the preservation composition may comprise propylene glycol. Propylene glycol is a hygroscopic compound that is highly miscible with water and exhibits relatively low volatility compared with water. These properties make propylene glycol suitable for use in compositions intended to suppress evaporation from aqueous systems.

[0064] When present in the preservation composition, propylene glycol may contribute to the formation of the low-volatility surface layer described above. Because propylene glycol evaporates more slowly than water, it may remain concentrated within the surface layer during the interruption period. The presence of propylene glycol at the paint-air interface may therefore assist in reducing the rate of water loss from the underlying paint.

[0065] Propylene glycol may also exhibit humectant behaviour by attracting and retaining moisture. This property may further assist in maintaining a moist environment at the exposed paint surface and reducing the rate at which the paint begins to thicken or form a skin.

[0066] In certain embodiments, the preservation composition may further comprise propylene glycol methyl acetate. Propylene glycol methyl acetate is an organic solvent that is miscible with many aqueous and organic coating systems. When included in the preservation composition, propylene glycol methyl acetate may assistin adjusting the spreading characteristics and wetting behaviour of the composition on the paint surface.

[0067] The presence of propylene glycol methyl acetate may also influence the viscosity and surface tension characteristics of the formulation, which may assist in achieving uniform distribution of the sprayed composition across the paint surface. In some implementations, the solvent properties of propylene glycol methyl acetate may further assist in maintaining compatibility between the preservation composition and the binder components present in the water-based paint.

[0068] In certain preferred embodiments, the preservation composition may comprise a mixture of propylene glycol and propylene glycol methyl acetate in proportions selected to achieve suitable evaporation suppression while maintaining compatibility with the paint formulation. For example, the composition may comprise a majority proportion of propylene glycol with a smaller proportion of propylene glycol methyl acetate. In some implementations, the proportion of propylene glycol may be within the range of approximately 90-99 percent by weight, while propylene glycol methyl acetate may be present in an amount of approximately 1-10 percent by weight. Such ratios may provide a balance between moisture-retention capability, spreading behaviour, and compatibility with the paint system.

[0069] Through the use of glycol-based components and compatible co-solvents, the preservation composition may effectively create a low-volatility surface layer that suppresses evaporative loss of water from the paint during a temporary interruption in painting operations.Water-Based Preservation Compositions Containing Surface -Active Additives

[0070] In certain embodiments, the preservation composition may comprise water as a principal component of the formulation. The presence of water may provide compatibility with water-based paints, particularly acrylic latex paints and similar aqueous coating systems. Because such paints themselves contain water as a primary carrier solvent, a preservation composition containing water may readily interact with the exposed paint surface without causing phase separation or incompatibility.

[0071] When sprayed onto the exposed paint surface, a water-containing preservation composition may spread across the paint and interact with the aqueous phase of the paint formulation. In certain implementations, the water component may assist in facilitating the spreading and distribution of the preservation composition across the exposed paint surface. The water may also contribute to maintaining hydration within the surface region of the paint during the interruption period.

[0072] In some embodiments, the preservation composition may further include one or more surface-active additives. Surface-active additives may modify the wetting characteristics of the sprayed composition, thereby promoting more uniform spreading across the exposed paint surface. Improved spreading behaviour may assist in forming a more continuous surface layer, which in turn may enhance the suppression of evaporative mass transfer from the underlying paint.

[0073] Surface-active additives may also influence the interfacial behaviour between the preservation composition and the paint surface. For example, such additives may reduce surface tension, allowing droplets of the sprayed composition to more readily coalesce and distribute across the paint surface. This may assist in achieving more complete coverage of the exposed paint with relatively small quantities of the preservation composition.

[0074] In certain embodiments, the preservation composition may include a low-VOC additive configured to promote spreading and surface-layer formation while maintaining compliance with environmental regulations governing volatile organic compound emissions. One example of such an additive may comprise a product marketed as LPG 26038 by BYK. Such additives may function as surface-modifying agents capable of promoting the formation of a stable surface layer when applied to the paint surface.

[0075] In certain preferred embodiments, the preservation composition may comprise a formulation including water, LPG 26038, and propylene glycol methyl acetate. In this arrangement, water may act as a primary carrier phase compatible with waterbased paints, while LPG 26038 may assist in modifying the spreading and interfacial behaviour of the composition on the paint surface. Propylene glycol methyl acetatemay function as a co-solvent that contributes to the wetting behaviour and volatility profile of the formulation.

[0076] In certain implementations, the preservation composition may comprise approximately 80 percent by weight water, approximately 16 percent by weight LPG 26038, and approximately 4 percent by weight propylene glycol methyl acetate. Such proportions may provide a formulation capable of forming a surface layer that spreads effectively across the paint surface while providing components having evaporation rates lower than that of water. As a result, the composition may suppress evaporative loss of water from the paint during the interruption period.

[0077] It will be appreciated that these component ratios may be adjusted depending on the particular characteristics of the target paint system, ambient environmental conditions, or desired evaporation suppression performance. The relative proportions of the components may therefore be varied while maintaining the functional behaviour described above.Compatibility with Paint Formulations and Absence of Paint-Forming Solids

[0078] In certain embodiments, the preservation composition may be formulated so as to be substantially free of pigment particles. Pigments are typically included in paint formulations to provide colour, opacity and optical properties. However, the inclusion of pigments in the preservation composition may be unnecessary and in some circumstances undesirable, as pigment particles could alter the colour balance of the paint once the preservation composition is mixed back into the paint following the interruption period. Accordingly, the preservation composition may be prepared without intentionally added pigment components.

[0079] Similarly, in certain embodiments the preservation composition may be substantially free of curing agents or crosslinking agents. Water-based paints commonly rely on mechanisms such as polymer particle coalescence, oxidative curing, or other film-forming reactions that may involve curing components or crosslinking additives. The presence of such curing agents in the preservation composition could potentially accelerate undesirable reactions within the paint during the interruption period. By omitting curing agents from the preservation composition,the formulation may avoid initiating or promoting curing reactions within the exposed paint.

[0080] In some implementations, the preservation composition may therefore consist primarily of liquids and additives selected for their volatility characteristics, wetting behaviour and compatibility with the paint system, rather than for their ability to form a coating film. This approach may allow the preservation composition to perform its intended function of suppressing evaporative loss of water while avoiding interference with the paint’s original film-forming chemistry.

[0081] Following the interruption period, the preservation composition may be mixed back into the paint using conventional agitation practices such as stirring or mechanical mixing. Because the composition is formulated to be compatible with aqueous paint systems, the components of the preservation composition may redistribute within the paint and form a substantially homogeneous mixture.

[0082] In certain embodiments, the presence of the preservation composition within the paint after remixing may not materially alter the colour, finish or curing behaviour of the paint. For example, because the preservation composition may be substantially free of pigments and curing agents, its introduction into the paint may not significantly affect the optical properties or film formation characteristics of the paint once applied to a substrate.

[0083] Compatibility between the preservation composition and the water-based paint may also be assisted by the use of water-miscible components such as glycols, glycol ethers, or other solvents that are compatible with typical paint binder systems. These materials may disperse readily within the aqueous phase of the paint when mixing occurs.

[0084] As a result, the preservation composition may temporarily modify the interfacial conditions at the exposed paint surface during an interruption in painting operations, while still allowing the paint to return to a substantially normal condition once the composition is redistributed within the paint. This behaviour may provide a practical advantage in that the same paint may be used after the interruption without requiring removal of surface skins, filtration, or disposal of partially dried material.First Formulation - Water, LPG 26038 and Propylene Glycol Methyl Acetate

[0085] In certain embodiments, the preservation composition may comprise a waterbased formulation including water, a surface-active additive, and a compatible cosolvent. One example of such a formulation may comprise water, an additive marketed as LPG 26038 by BYK, and propylene glycol methyl acetate (PGMA). This formulation may provide a preservation composition capable of spreading across an exposed paint surface and forming a surface layer enriched in relatively low-volatility components, thereby suppressing evaporative loss of water from the underlying paint.

[0086] In certain preferred embodiments, the preservation composition may comprise approximately 80 percent by weight water, approximately 16 percent by weight LPG 26038, and approximately 4 percent by weight propylene glycol methyl acetate. These proportions may provide a formulation capable of producing the surface-layer behaviour described above while maintaining compatibility with water-based paint systems.

[0087] Water may serve as the principal carrier phase within the formulation. Because water is already the primary solvent present in most architectural water-based paints, the presence of water in the preservation composition may facilitate compatibility with the exposed paint surface. The water component may also assist in distributing the preservation composition across the paint surface during spraying.

[0088] LPG 26038 may function as a surface-active additive that influences the spreading and interfacial behaviour of the preservation composition. Such additives may modify the surface tension characteristics of the sprayed droplets, allowing the droplets to spread and coalesce across the exposed paint surface. This behaviour may assist in forming a relatively continuous surface layer across the exposed paint. In addition, additives of this type may contain components having evaporation characteristics that differ from water, thereby contributing to the formation of a surface region enriched with lower-volatility constituents.

[0089] Propylene glycol methyl acetate may function as a co-solvent within the formulation. The inclusion of PGMA may assist in adjusting the wetting behaviour, volatility profile and spreading characteristics of the preservation composition. Insome embodiments, PGMA may also improve compatibility between the preservation composition and the binder components of the water-based paint. The presence of PGMA may therefore contribute to the ability of the preservation composition to later redisperse within the paint when mixing occurs.

[0090] In certain implementations, the preservation composition may be prepared by combining the components in a suitable mixing vessel. For example, water may first be introduced into the vessel, after which LPG 26038 may be added with agitation to promote uniform dispersion. Propylene glycol methyl acetate may then be added to the mixture while stirring continues. Mixing may be performed using conventional mechanical stirring equipment until a substantially homogeneous liquid formulation is obtained.

[0091] Once prepared, the formulation may be transferred into a spray delivery container such as an aerosol canister or other pressurised dispensing system. The formulation may be packaged together with a suitable propellant capable of atomising the composition when dispensed through a spray nozzle. As described earlier, suitable propellants may include hydrocarbon propellants or dimethyl ether, although other propellant systems may also be employed.

[0092] When the formulation is sprayed onto an exposed surface of water-based paint, droplets of the composition may deposit across the paint surface and subsequently spread due to the wetting characteristics imparted by the surface-active additive. As the droplets spread and merge, a surface layer may form across the exposed paint. Within this layer, components having relatively low evaporation rates compared with water may become enriched relative to the underlying paint.

[0093] The presence of this surface layer may alter the mass transfer conditions at the paint-air interface. In particular, the layer may reduce the rate at which water evaporates from the paint surface into the surrounding atmosphere. By slowing this evaporation process, the onset of drying phenomena such as thickening or skin formation may be delayed.

[0094] Testing of a formulation comprising approximately 80 percent water, 16 percent LPG 26038, and 4 percent propylene glycol methyl acetate has indicated thatthe composition may effectively preserve exposed water-based paint during interruptions in painting operations. In one evaluation conducted by an experienced trade painter, the composition was sprayed onto paint in a tray during a break in painting activity. The paint remained workable after a period of approximately one hour and also remained usable after an extended period of approximately twenty-four hours. Upon agitation of the paint in the tray, the preservation composition was readily mixed back into the paint, allowing painting operations to resume without noticeable degradation in paint handling or application characteristics.

[0095] It will be appreciated that the specific proportions of the components described above may be adjusted depending on the characteristics of the target paint formulation or the environmental conditions in which the paint is used. For example, the relative proportions of water, LPG 26038 and PGMA may be varied while maintaining the ability of the composition to form a surface layer that suppresses evaporative water loss from the exposed paint. The formulation described above should therefore be regarded as an example of a preservation composition capable of implementing the method described earlier.Second Formulation - Propylene Glycol and Propylene Glycol Methyl Acetate

[0096] In certain embodiments, the preservation composition may comprise a formulation primarily based on propylene glycol together with a compatible cosolvent. One example of such a formulation may comprise propylene glycol and propylene glycol methyl acetate (PGMA). This formulation may provide a preservation composition capable of forming a low-volatility surface layer over exposed waterbased paint, thereby suppressing evaporative loss of water from the paint during a temporary interruption in painting.

[0097] In certain preferred embodiments, the preservation composition may comprise approximately 95 percent by weight propylene glycol and approximately 5 percent by weight propylene glycol methyl acetate. These proportions may provide a composition exhibiting suitable volatility characteristics and compatibility with water-based paint formulations.

[0098] Propylene glycol may serve as the principal component of the formulation. Propylene glycol is a hygroscopic compound that is completely miscible with water and commonly used in a variety of aqueous formulations. The compound exhibits a vapour pressure significantly lower than that of water at ambient temperature. As a result, propylene glycol evaporates more slowly than water and may remain present at the paint-air interface for extended periods following application.

[0099] When the formulation is sprayed onto the exposed surface of a water-based paint, droplets of the composition may deposit across the paint surface. Due to the wetting characteristics of the liquid formulation, these droplets may spread across the exposed paint surface and coalesce to form a surface layer. Because propylene glycol has a relatively low volatility, the resulting surface layer may remain substantially present during the interruption period.

[0100] The presence of propylene glycol within the surface layer may influence the interfacial environment at the paint-air boundary. In particular, the surface layer may reduce the rate of evaporative mass transfer of water from the paint to the surrounding atmosphere. Propylene glycol may also exhibit humectant behaviour, meaning that it may retain moisture within the surface region of the paint. These combined effects may delay the onset of drying phenomena such as thickening or skin formation at the exposed paint surface.

[0101] Propylene glycol methyl acetate may be included as a co-solvent within the formulation. The presence of PGMA may influence the spreading behaviour and surface tension characteristics of the sprayed composition. In certain implementations, PGMA may assist in enabling the sprayed droplets to distribute more uniformly across the paint surface. The solvent properties of PGMA may also contribute to compatibility between the preservation composition and the binder system present in the water-based paint.

[0102] In certain implementations, the preservation composition may be prepared by combining propylene glycol and propylene glycol methyl acetate within a suitable mixing vessel. The components may be mixed using conventional stirring equipment until a homogeneous liquid formulation is obtained. Because both components areliquids under ambient conditions and are mutually miscible, the formulation may be prepared using relatively simple mixing procedures.

[0103] Once prepared, the formulation may be transferred to a spray dispensing container such as an aerosol canister or other pressurised spray device. A suitable propellant system may be included to allow the formulation to be atomised when dispensed. The spray delivery system may enable relatively uniform distribution of the composition across exposed paint surfaces.

[0104] When applied to the exposed surface of water-based paint, the propylene glycol-based formulation may spread to form a surface layer enriched with relatively low-volatility components. This layer may reduce the rate at which water evaporates from the underlying paint during an interruption in painting activity. The paint may therefore remain workable for a longer period of time than would otherwise occur without application of the preservation composition.

[0105] Following the interruption, the preservation composition may be mixed into the paint through agitation of the paint using conventional techniques such as stirring or rolling. Because the formulation comprises water-miscible components compatible with aqueous paint systems, the composition may readily redistribute within the paint. In many practical implementations, the presence of the preservation composition within the paint after remixing may not materially affect the colour, finish, or curing behaviour of the paint once applied to a substrate.

[0106] The propylene glycol-based formulation may therefore provide a simple and effective preservation composition capable of suppressing evaporative drying of exposed water-based paint while maintaining compatibility with the paint formulation and allowing subsequent remixing prior to continued painting.Exemplary Method of Use

[0107] The following example is provided for illustrative purposes to demonstrate one manner in which a preservation composition as described above may be used in practical painting operations. This example is not intended to limit the scope of the method and should be regarded as a representative use case.

[0108] In an example scenario, a painter is applying a water-based acrylic wall paint using a conventional paint roller and paint tray. During painting, a quantity of paint is poured into the tray such that a reservoir of paint collects in the deeper region of the tray while a thin layer of paint is distributed across the inclined rolling surface. As painting progresses, the roller is repeatedly loaded with paint from the tray.

[0109] At a certain point during the painting operation, the painter may temporarily interrupt the work, for example for a break, a change of tools, or completion of another task. During such interruptions, the exposed surface of paint within the tray may normally begin to dry due to evaporation of water into the surrounding air. Under typical conditions this may lead to thickening of the paint near the surface and eventual formation of a surface skin.

[0110] In the present example, prior to leaving the work area, the painter applies a preservation composition as described above by spraying the composition across the exposed surface of the paint in the tray. The spray may be delivered from a handheld aerosol container held above the tray. The painter may apply the spray in one or more sweeping passes so that droplets of the composition are distributed across the exposed paint surface.

[0111] Following application, the sprayed droplets deposit on the paint surface and spread across the exposed paint to form a surface layer. This layer may contain components having evaporation rates lower than that of water and may therefore suppress evaporative loss of water from the underlying paint. The presence of the surface layer may delay the onset of drying phenomena such as surface thickening or skin formation.

[0112] In this example, the painter leaves the paint tray undisturbed for a period of time. The interruption period may be relatively short, such as approximately one hour, or may extend for longer durations, such as several hours or overnight. During this time, the preservation composition remains present on the paint surface and continues to suppress evaporation of water from the paint.

[0113] Upon returning to the painting task, the painter may agitate the paint in the tray using the roller or by stirring the paint with a suitable tool. This agitation mixesthe preservation composition into the paint, thereby redistributing the composition throughout the paint. The paint may return to a substantially homogeneous condition suitable for continued application.

[0114] The painter may then resume painting using the same paint without removing surface skins or discarding partially dried material. In this manner, the preservation composition may enable the paint to remain usable during temporary interruptions in painting activity.

[0115] It will be appreciated that similar procedures may be used with other painting implements or paint containers. For example, the preservation composition may be sprayed onto paint present on a roller, a paint brush, or within an open paint container prior to an interruption in painting. Following the interruption, the composition may be mixed into the paint through agitation prior to continued use.Technical Effects and Advantages

[0116] The arrangements described above provide a practical approach for temporarily inhibiting drying of water-based paints during interruptions in painting operations. When a preservation composition is applied to an exposed paint surface, a surface layer may form that modifies the interfacial conditions between the paint and the surrounding air. This layer comprises components having evaporation rates lower than that of water. The presence of such components at the paint-air interface may reduce evaporative mass transfer of water from the paint, thereby delaying drying processes that would otherwise occur during periods of non-use.

[0117] Through this mechanism, exposed paint may remain workable for longer periods of time than would normally occur in the absence of the preservation composition. For example, the formation of the surface layer may reduce the likelihood of skin formation, thickening, or premature coagulation of paint components. This behaviour may be particularly beneficial where painting operations are temporarily interrupted, such as during breaks, shift changes, or transitions between stages of work.

[0118] In certain embodiments, the preservation composition may include hygroscopic or low-volatility components that assist in maintaining moisture at theexposed paint surface. Such components may attract or retain water in the vicinity of the paint surface and thereby contribute to the suppression of evaporation. In other embodiments, spreading behaviour of the composition across the paint surface may assist in establishing a relatively continuous layer, which may further enhance the evaporation-suppressing effect.

[0119] In some implementations, the preservation composition may be delivered as a spray, for example from a pressurised aerosol container. Spray delivery may enable relatively uniform distribution of the composition across exposed paint surfaces and may allow a user to apply the composition quickly prior to an interruption in painting. The use of spray delivery may also assist in producing droplets that spread across the paint surface to form the surface layer described above.

[0120] Various formulations of the preservation composition may be employed. In certain embodiments, compositions including glycol-based components may be used. Such materials may exhibit relatively low volatility and hygroscopic behaviour that assists in suppressing evaporation from the paint surface. In other embodiments, formulations including water together with surface-active additives and compatible co-solvents may be used. Such formulations may provide favourable spreading characteristics and may facilitate the formation of a surface layer capable of suppressing evaporation.

[0121] The preservation compositions described herein may be formulated so as to be compatible with water-based paint systems. In many cases, the components of the preservation composition may be miscible with or dispersible within the paint. As a result, when painting resumes and the paint is agitated, the preservation composition may redistribute within the paint without forming undesirable residues or separate phases. This behaviour may allow painting operations to continue using the same paint following an interruption.

[0122] In certain implementations, the preservation composition may be formulated without pigments or curing agents. Such an approach may reduce the likelihood that the preservation composition will materially affect the colour or curing characteristics of the paint once the composition has been mixed back into the paint. However, it willbe appreciated that variations in formulation may be possible while still achieving the evaporation-suppressing effects described above.

[0123] Overall, the techniques described herein may allow painters to temporarily preserve exposed water-based paint during interruptions in painting activity without requiring sealing of containers, wrapping of painting tools, or discarding partially dried paint. By acting directly at the paint surface to suppress evaporation, the preservation composition may provide a practical and efficient means of maintaining paint usability during pauses in painting operations.

[0124] The foregoing description, for purposes of explanation, used specific nomenclature to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that specific details are not required in order to practise the invention. Thus, the foregoing descriptions of specific embodiments of the invention are presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed as obviously many modifications and variations are possible in view of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. It is intended that the following claims and their equivalents define the scope of the invention.

Claims

Claims1. A method of inhibiting drying of a water-based paint during a temporary interruption in painting, the method comprising:applying a sprayable preservation composition onto an exposed surface of the water-based paint;allowing the preservation composition to spread across the exposed paint surface and form a surface layer comprising one or more components having a lower evaporation rate than water;wherein the surface layer reduces evaporative mass transfer of water from the exposed paint to ambient air and thereby delays drying of the paint; andupon resumption of painting, mixing the preservation composition into the water-based paint such that the preservation composition redistributes within the paint.

2. The method of claim 1, wherein the preservation composition comprises one or more hygroscopic components configured to retain moisture at the exposed paint surface.

3. The method of claim 1, wherein the preservation composition comprises one or more glycol compounds having a vapour pressure lower than that of water at ambient temperature.

4. The method of claim 1, wherein the preservation composition comprises a carrier phase that spreads across the exposed paint surface to form the surface layer.

5. The method of claim 1, wherein the preservation composition is delivered as an aerosol spray.

6. The method of claim 1, wherein the preservation composition comprises propylene glycol.

7. The method of claim 6, wherein the preservation composition further comprises propylene glycol methyl acetate.

8. The method of claim 7, wherein the preservation composition comprises approximately 90-99 wt% propylene glycol and approximately 1-10 wt% propylene glycol methyl acetate.

9. The method of claim 1, wherein the preservation composition comprises water.

10. The method of claim 9, wherein the preservation composition further comprises a low-VOC surface-active additive.

11. The method of claim 10, wherein the preservation composition comprises a formulation including water, a low-VOC additive comprising LPG 26038, and propylene glycol methyl acetate.

12. The method of claim 11, wherein the preservation composition comprises approximately80 wt% water,16 wt% LPG 26038, and4 wt% propylene glycol methyl acetate.

13. The method of claim 1, wherein the preservation composition is substantially free of pigment particles and curing agents.

14. The method of claim 1, wherein the preservation composition redistributes within the paint upon mixing without materially altering the colour, finish, or curing behaviour of the paint.

15. A sprayable paint preservation composition comprising:one or more low-volatility components having an evaporation rate lower than that of water;wherein, when used by applying the composition onto an exposed surface of a water-based paint, the composition spreads across the exposed paint surface to form a surface layer that reduces evaporative mass transfer of water from the paint to ambient air and thereby delays drying of the paint.

16. The composition of claim 15, wherein the composition comprises one or more hygroscopic components configured to retain moisture at the exposed paint surface.

17. The composition of claim 15, wherein the composition comprises propylene glycol and propylene glycol methyl acetate.

18. The composition of claim 17, wherein the composition comprises approximately 90-99 wt% propylene glycol and approximately 1-10 wt% propylene glycol methyl acetate.

19. The composition of claim 15, wherein the composition comprises water, LPG 26038, and propylene glycol methyl acetate.

20. The composition of claim 19, wherein the composition comprises approximately 80 wt% water,16 wt% LPG 26038, and4 wt% propylene glycol methyl acetate.