Patent Description:
In response to the coronavirus pandemic, airlines and original equipment manufacturers (OEMs) have focused on improving interior hygiene through the unprecedented use of cleaning products, disinfectants, barrier coatings and ultraviolet (UV) sanitation.

Desirable properties of articles include durability, resistance to fluids, resistance to staining, color fastness, and cleanability. These properties are particularly important in high-traffic interior applications, for instance aircraft passenger cabin environments. These properties can be enhanced through article design, material choice and use of barrier coatings. For example, articles shapes can be optimized for cleanability, materials can be engineered for better performance, and barrier coatings such as siloxane-based coatings can be applied to provide protection against damage from wear, chemicals, exposure to fluids, UV, etc. Coatings and additives can also be used to mitigate the potential spread of infectious agents.

While most articles can be cleaned, at least to a degree, articles in certain environments are subject to constant cleaning using rigorous cleaning processes and harsh chemicals to ensure sanitization. While a degree of cleanability can be assumed from most cleaning processes, there are currently no solutions for measuring and precisely quantifying the cleanability of a surface. Such a solution could be used to ensure sanitization, confirm the effectiveness of a cleaning process, determine the integrity of a barrier coating, and facilitate future designs of articles and barrier coatings, among other purposes. Determining the cleanability of an article or surface is disclosed in <CIT>, <CIT> and <CIT>.

To achieve the foregoing and other advantages, the present invention provides a method for determining cleanability of a surface of an article, as defined by claim <NUM>.

Particular embodiments of the invention are defined by the dependent claims. The scope of the invention is defined and limited by the appended claims.

In some embodiments, the percentage difference between the obtained reference ATP bioluminescence measurement and the obtained ATP bioluminescence measurement of the cleaned surface provides a cleanability score, wherein a cleanability score greater than about <NUM>% corresponds to a passing cleanability score, and wherein a cleanability score less than about <NUM>% corresponds to a failing cleanability score.

In some embodiments, the component in solution is ATP disodium salt.

In some embodiments, the component comprises less than about <NUM>% by volume of the solution, more preferably less than about <NUM>% by volume of the solution.

In some embodiments, the cleaning process includes the steps of applying a cleaning solution to the surface of the article and removing the cleaning solution from the surface of the article, and an optional intermediate wiping step.

This brief summary is provided solely as an introduction to subject matter that is fully described in the detailed description.

Before explaining one or more embodiments of the disclosure in detail, it is to be understood that the embodiments are not limited in their application to the details of construction and the arrangement of the components or steps or methodologies set forth in the following description. In the following detailed description of embodiments, numerous specific details may be set forth to provide a more thorough understanding of the disclosure. However a method in accordance with the present invention must at least comprise the steps defined in appended independent claim <NUM>.

The appearances of the phrase "in some embodiments" in various places in the specification are not necessarily all referring to the same embodiment, and embodiments may include one or more of the features expressly described or inherently present herein, along with any other features which may not necessarily be expressly described or inherently present in the instant disclosure.

Broadly speaking, the present disclosure provides methods for measuring and quantifying the cleanability of an article, for instance a surface of an aircraft interior component. In a first aspect, an artificial "dirt" is introduced to a surface under test to simulate a sullied condition. The sullied surface is then subjected to at least one cleaning process. Pre-cleaning reference and post-cleaning light measurements obtained using an ATP bioluminescence meter are compared to determine a measurement difference corresponding to the cleanability of the surface. In some embodiments, the measurement difference is assigned a cleanability score used to, for example, determine a passing or failing cleanability, modify the cleaning process, indicate the need for a second or subsequent cleaning, modify the barrier coating formulation, redesign of the article, etc. In a second aspect, a detectable fluorescent indicator is introduced to the surface of the article. The article is then subjected to at least one cleaning process and the measured difference in light intensity pre-cleaning and post-cleaning is used to quantify the cleanability of the surface, the results of which can be used for the purposes discussed above. The methods according to the present disclosure provide solutions for objective verification measures of the cleanability of the surface of an article that can be used to facilitate new article designs, materials, barrier coatings, cleaning processes, cleaners, etc..

With reference to <FIG>, a first method <NUM> according to the present disclosure is used to quantify the cleanability of a surface of an article, for instance a high-contact surface located in a passenger or crew area of a passenger vehicle such as an aircraft, bus, train, ship, etc. Examples of surface materials under test may include, but are not limited to, synthetic or natural fabrics, plastics, metals, composites and composite finishes, wood, glass, leather, etc. Article environments may include, but are not limited to, passenger cabins, crew quarters, lavatories, galleys and cockpits. Other environments may include schools, hospitals, public buildings, etc. In the case of passenger vehicles, the article may be an element of a passenger seat, a passenger suite, an interior panel, an overhead bin, a door, a wall, a passenger amenity, a control panel, a passenger service unit, a lavatory fixture, galley equipment, and beverage carts, among others. In some embodiments, the article may be an element of a mechanism operable for manipulating another element, for example, a handle, lock, latch, switch, control panel or other high-contact surface.

In embodiments in accordance with the invention, the surface comprises a barrier coating providing protection against at least one of fluids, disinfectants, chemicals and ultra violet light. For example, the surface may be coated with a single layer or multiple layers of multifunctional barrier coating. In other examples, each coating layer may impart a singular functionality and multiple layers may be registered one atop another to provide a multi-layer coating solution. Coating functionalities may include, but are not limited to, self-cleaning properties, hydrophobicity, fluid resistance, chemical resistance, UV resistance, resistance to wear from physical contact, color fastness, improved flame smoke and toxicity (FST) performance, and antimicrobial properties.

In some embodiments, the barrier coating(s) may be applied via solution, and may include components, individually or in combination, such as base coating components such as siloxanes, silazanes, fluoro-substituted siloxanes or silazanes, polymethylsisequioxane, and polydimethylsiloxane, a binder system including hydrophobic polymer(s) or curable resin(s), a hydrophobic polymer to impart increased water repellency and durability of water repellant as well as resistance to the effects of UV radiation, abrasion and chemical disinfectants, a solvent including tetrahydrofuran for providing uniform coating thickness and rapid drying, as well as good working viscosity, an FST performance enhancing component such as micro- or nano-sized clay particles such as montmorillonite and bentonite functionalized with organosilanes to promote dispersion within the solution, and UV resistant components such as titanium dioxide and triazoles. Different barrier coating formulations may react differently to different cleaning processes based on their components, component volume percentages, layered arrangement, application process, etc., each of which can be optimized utilizing the cleanability measurement methods disclosed herein. Other coating compositions are envisioned and intended.

According to the method <NUM>, in a step <NUM> an article having a surface under test is provided, for instance an anticipated high-contact surface of an article as discussed above. Also as stated above, the surface is coated with a barrier coating and may be any material type. In a step <NUM>, a solution according to the present disclosure is provided. In some embodiments, the solution includes an ATP bioluminescent component, for instance ATP disodium salt or the like. In some embodiments, the ATP is diluted to an amount less than <NUM>% by volume of the solution, more preferably less than about <NUM>% by volume of the solution, and most preferably less than about <NUM>% by volume of the solution.

The ATP containing solution (i.e., the "solution") is formulated to provide a reference relative light unit (RLU) measurement as measured using an ATP bioluminescence meter configured to read the amount of light produced from a surface sample, wherein the light produced is proportional to the amount of ATP. The solution, when applied, introduces an artificial sullied condition to the surface that provides a reference measurement by which cleanability can be quantified. In other words, the ATP solution of a predetermined ATP concentration provides a precise and customizable reference measurement independent of other contaminants that may be present on the surface.

In a step <NUM>, the diluted ATP solution is applied to the surface of the article. In an optional step, the surface may be readied (e.g., cleaned) in one or more cleaning steps prior to step <NUM> to avoid contamination of the ATP solution. Solution application techniques may include, but are not limited to, spraying, wiping dipping, pouring, etc. The solution may be applied under ambient or controlled conditions and the surface may or may not be subjected to a pre-treatment process prior to solution application. The applied solution may be allowed to dry or cure on the surface. In a step <NUM>, a reference light measurement from the ATP solution is obtained using the ATP bioluminescence meter.

In a step <NUM>, the surface of the article having the solution applied thereto is subjected to at least one cleaning process. The cleaning process may be performed in one or more steps or repetitions of steps. Cleaning may include application of chemicals, disinfectants, solvents, water, etc., via applications such as spraying, wiping, etc. Cleaning processes may also include UV sanitation. Cleaning processes may be singular processes or combinations of different processes, and performed under ambient or controlled conditions. For example, cleaning processes may include conventional techniques using conventional cleaners ordinarily and routinely used for cleaning a predetermined type of article. For example, in the case of a passenger tray table, the cleaning process may include conventional spraying and wiping with a disinfectant cleaner under ambient conditions. Cleaning processes, cleaners, amounts, time durations, etc., may be recorded for use in evaluating cleaning performance.

In a step <NUM>, after the cleaning process is complete, at least one post-cleaning light measurement is obtained using the ATP bioluminescence meter. In a step <NUM>, the post-cleaning light measurement is compared to the reference light measurement to determine a measurement difference indicative of the effectiveness of the cleaning process and/or cleanability of the surface. According to the invention, the reference light measurement indicates a completely sullied surface, expressed as a percentage such as about <NUM>%, wherein completely is a relative term. The obtained post-cleaning process light measurement is presumably less than <NUM>%, but in some cases may be the same as the reference measurement in situations where the cleaning process is entirely ineffective at removing any amount of ATP. The post-cleaning light measurement obtained, measured for example in RLUs, indicates the amount of ATP remaining on the surface. For example, a <NUM>% reduction in measured light may indicate a <NUM>% reduction in ATP post-cleaning and thus a partially clean surface. In a non-limiting example, a measurement difference of at least <NUM>% may indicate a 'passing' surface cleanability, whereas a measurement difference less than <NUM>% may indicate a 'failing' surface cleanability. Post-cleaning measurements can be taken once after each cleaning process, after each step of a cleaning process, after subsequently performed cleaning processes, etc. Cleanability may be scored other than with measured light corresponding to percentage of clean, and predetermined measurement differences may be selected to determine threshold levels of acceptable surface cleanability. For example, percentages thresholds may include a <NUM>% difference, <NUM>% difference, <NUM>% difference, etc..

For example, the obtained reference light measurement and the difference between the reference light measurement and the post-cleaning light measurement may be expressed as a percentage or otherwise. In the case of percentages, the obtained reference measurement may correspond to a <NUM>% ATP presence on the surface (e.g., dirty), a <NUM>% measurement difference may correspond to a <NUM>% ATP presence on the surface (e.g., clean), and less than a <NUM>% difference may correspond to an amount of ATP remaining on the surface (e.g., partially clean or partially dirty).

In an optional step <NUM>, performed after the first light measurement is taken, the article may be subjected to at least one additional cleaning process, and at least one additional post-cleaning light measurement may be taken and compared against the reference light measurement and/or other post-cleaning light measurements. <FIG> shows schematically the implementation of the method according to <FIG>. The ATP solution <NUM> is applied to the surface <NUM> of the article <NUM> and the reference light measurement is obtained using an ATP bioluminescence meter <NUM>. In an alternative embodiment, the light measurement of the reference solution may be a known value. The surface <NUM> is subjected to at least one cleaning process and at least one post-cleaning light measurement is obtained using the ATP bioluminescence meter <NUM>. The light measurements are then compared to determine the light measurement difference, which can be assigned a score that provides an indication of design/cleaning process capability.

With reference to <FIG>, another method <NUM> according to the present disclosure, which does not fall within the scope of the appended claims, utilizes a fluorescent indicator to determine surface cleanability. Similar to the above method, in a step <NUM> an article having a surface under test is provided, and in a step <NUM>, a solution including a detectable component is provided, preferably in a diluted amount. In some embodiments, the detectable component is a fluorescent dye. Examples of fluorescent dyes include, but are not limited to, fluorescent indicators such as any fluorescent compound capable of absorption in the UV spectrum and emission in the visible spectrum. For example, the fluorescent compound may absorb radiation in the <NUM>-<NUM> wavelength range, more preferably in the <NUM>-<NUM> wavelength range, and most preferably in the <NUM>-<NUM> wavelength range, and emit radiation in the <NUM>-<NUM> wavelength range, and more preferably emit visible light in the <NUM>-<NUM> wavelength range. Suitable fluorescent compounds may be transparent in the presence of visible light and uncolored so as not to alter the color and/or transparency of the surface of the article. Suitable fluorescent compounds can include, but are not limited to, commercially available fluorescent dyes, pigments, colorants and brighteners.

A specific, non-limiting example of a suitable fluorescent compound can include <NUM>-[[<NUM>-[bis(<NUM>-hydroxyethyl)amino]-<NUM>-(<NUM>-sulfonatoanilino)-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl]amino]-<NUM>-[(E)-<NUM>-[<NUM>-[[<NUM>-[bis(<NUM>-hydroxyethyl)amino]-<NUM>-(<NUM>-sulfonatoanilino)-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl]amino]-<NUM>-sulfonatophenyl]ethenyl]benzenesulfonate. Other examples include anionic dye compounds of λex < <NUM> and λem > <NUM> may be ideally invisible under normal visible light and fluoresce under UV light (e.g., tetrasodium <NUM>,<NUM>'-bis[[<NUM>-[bis(<NUM>-hydroxyethyl)amino]-<NUM>-(<NUM>-sulphonatoanilino)-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl]amino]stilbene-<NUM>,<NUM>'-disulphonate], disodium,<NUM>-[[<NUM>-anilino-<NUM>-[<NUM>-hydroxyethyl(methyl)amino]-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl]amino]-<NUM>-[<NUM>-[<NUM>-[[<NUM>-anilino-<NUM>-[<NUM>-hydroxyethyl(methyl)amino]-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl]amino]-<NUM>-sulfonatophenyl]ethenyl]benzenesulfonate, disodium <NUM>,<NUM>'-bis(<NUM>-anilino-<NUM>-morpholino-s-triazin-<NUM>-ylamino)-<NUM>,<NUM>'-stilbenedisulfonate, disodium-<NUM>-[[<NUM>-(<NUM>-methylanilino)-<NUM>-morpholin-<NUM>-yl-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl]amino]-<NUM>-[<NUM>-[<NUM>-[[<NUM>-(<NUM>-methylanilino)-<NUM>-morpholin-<NUM>-yl-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl]amino]-<NUM>-sulfonatophenyl]ethenyl]benzenesulfonate, hexasodium-<NUM>-[[<NUM>-[(<NUM>-amino-<NUM>-oxopropyl)-(<NUM>-hydroxyethyl)amino]-<NUM>-[<NUM>-[<NUM>-[<NUM>-[[<NUM>-[(<NUM>-amino-<NUM>-oxopropyl)-(<NUM>-hydroxyethyl)amino]-<NUM>-(<NUM>,<NUM>-disulfonatoanilino)-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl]amino]-<NUM>-sulfonatophenyl]ethenyl]-<NUM>-sulfonatoanilino]-<NUM>,<NUM>,<NUM>-triazin-<NUM>-yl]amino]benzene-<NUM>,<NUM>-disulfonate, and related, as well as fluorescein-SA, Lucifer yellow, sulforhodamine-B or sulforhodamine-<NUM>, pyranine, HPTS or HPTS(Lys)<NUM>, MPTS, CTR, TSPP, TCPP, PTCA), Dyes (<<NUM> wt%), triazine-stilbene, coumarins, imidazolines, diazoles, triazoles, benzoxazoles, and biphenyl stilbenes, individually or in combinations thereof.

In a step <NUM>, the solution is applied to the surface of the article. In an optional step, the surface may be cleaned in one or more cleaning steps prior to step <NUM> to avoid contamination of the solution affecting light intensity measurement. Solution application techniques may include, but are not limited to, spraying, wiping dipping, and pouring. The solution may be applied under ambient or controlled conditions and the surface may or may not be subjected to a pre-treatment process prior to solution application. The applied solution may be allowed to dry or cure on the surface. In a step <NUM>, a reference light intensity measurement is obtained using, for example, a fluorescence detector configured to excite the fluorescent dye in solution with excitation light of a predetermined wavelength and extract the predetermined fluorescence wavelengths and measure intensity with a photomultiplier.

In a step <NUM>, the surface of the article having the solution applied thereto is subjected to a cleaning process. The cleaning process may be performed in one or more steps or repetitions of steps. Cleaning may include application of chemicals, disinfectants, solvents, water, etc., via applications such as spraying, wiping, etc. Cleaning processes may also include UV sanitation. Cleaning processes may be singular processes or combinations of different processes, and performed under ambient or controlled conditions. For example, cleaning processes may include conventional techniques using conventional cleaners ordinarily and routinely used for cleaning a predetermined type of article. In a specific non-limiting example, the article may be a tray table in an aircraft, and the cleaning process may include conventional spraying and wiping with a disinfectant cleaner. Cleaning processes, amounts, time durations, etc. may be recorded for use in evaluating cleaning performance.

In a step <NUM>, following the at least one cleaning process, at least one post-cleaning light intensity measurement is obtained using the fluorescence detector. In a step <NUM>, the post-cleaning light intensity measurement is compared to the reference light intensity measurement to determine a light intensity difference indicative of the effectiveness of the at least one cleaning process and ultimately the cleanability of the surface. Similar to the above method <NUM>, the reference light intensity measurement can be expressed as a percentage indicating a predetermined sullied condition of the surface. The same applies for the subsequently obtained measurements and measurement differences.

In an optional step <NUM>, the article may be subjected to at least one additional cleaning process, and at least one additional post-cleaning light intensity measurement may be obtained and compared to the reference light intensity measurement and/or other post-cleaning light intensity measurements. <FIG> shows schematically the implementation of the method according to <FIG>. The solution <NUM> is applied to the surface <NUM> of the article <NUM> and the reference light intensity measurement is obtained. In an alternative embodiment, the light intensity measurement of the solution is a known value. The surface <NUM> is subjected to at least one cleaning process and at least one post-cleaning light intensity measurement is obtained to determine the measurement difference between the pre- and post-cleaning light intensity measurements. As discussed above, the measurement difference may be assigned a cleanability score indicative of the ability to clean the surface using a predetermined cleaning process.

According to the present disclosure, a system may include a light source for producing the excitation UV radiation. The light source may be configured to emit radiation in a wavelength, for example, from <NUM> to <NUM>. For example, the system may include a blacklight. Light generated by the light source may be directed to the surface. The radiation from the light source may interact with the fluorescent indicator in the solution thereby causing the fluorescent indicator to emit light (e.g., visible light in the <NUM> to <NUM> wavelength range). In some embodiments, the system may be configured to generate an image of the emitted light from the fluorescent indicator. The image of the emitted light from the fluorescent indicator may be generated by a detector, and such detection may occur by analog or digital means. For example, the detector may include, but is not limited to, an ultra-violet (UV) detector, a charge couple device (CCD) detector, a time delay and integration (TDI) detector, a photomultiplier tube (PMT), an avalanche photodiode (APD), a complementary metal-oxide-semiconductor (CMOS) sensor, or the like. The image may have an associated brightness or intensity (e.g., in lumens). The image may also include a color standard. The image may also be a greyscale image.

The system may further include a controller including a memory and a processor, wherein the controller is communicatively coupled with the detector. In this regard, the image generated by the detector may be provided to the controller of the system and stored in the memory. The controller may also process the image to determine an intensity profile. The memory may also include a model for estimating cleanability based on the received refence and post-cleaning images. The model may correlate various data associated with the images (e.g., a luminosity, a brightness, a color standard, etc.) with a cleanability of the surface. The system may be handheld for in field use and may include a power source for powering various components of the system, such as, but not limited to, the controller, detector and the light source. The system may also be configured to image the surface under ambient lighting conditions or under conditions with no ambient lighting.

Claim 1:
A method for determining cleanability of a surface of an article, comprising the steps of:
providing (<NUM>) an article having a surface to be cleaned;
providing (<NUM>) a solution comprising an ATP component, in a diluted amount, measurable in relative light units, RLUs, using an adenosine triphosphate, ATP, bioluminescence meter;
applying (<NUM>) the solution to the surface of the article;
obtaining (<NUM>), using an ATP bioluminescence meter configured to measure relative RLUs, a reference light measurement of the surface;
subjecting (<NUM>) the surface of the article having the solution applied thereto to a cleaning process;
obtaining (<NUM>), using the ATP bioluminescence meter, a light measurement of the cleaned surface; and
quantifying (<NUM>), based on a measurement difference between the obtained reference light measurement and the obtained light measurement of the cleaned surface, cleanability of the surface of the article;
characterized in that
each of the obtained reference light measurement and the quantified measurement difference between the reference light measurement and the light measurement of the cleaned surface are expressed as a percentage, and wherein the obtained reference light measurement corresponds to a <NUM>% sullied surface, a <NUM>% difference between the obtained reference light measurement and the obtained light measurement of the cleaned surface corresponds to a completely unsullied surface, and less than a <NUM>% difference between the obtained reference light measurement and the obtained light measurement of the cleaned surface corresponds to a partially sullied surface; and
in that the surface of the article comprises a barrier coating providing protection against at least one of fluids, disinfectants, chemicals and ultra violet light.