TECHN ICAL FI ELD

[0001] The present disclosure relates to a polymeric coating composition for wooden based furniture with improved adhesion, and also presents improved resistance to staining, namely by water, mineral oil, coffee and ethanolic solutions. Additionally, the polymeric coating of the present composition allows the easy cleaning of the furniture, due to their specific properties of sliding for hydrophilic liquids as well as for lipophilic liquids. The polymeric coating composition showed to be clean resistant and able to maintain its performance after several cleaning cycles. Furthermore, the present disclosure relates to a method to obtain said coating composition, and also to furniture comprising said coating composition.

BACKGROUND

[0002] Functional smart homes are a growing reality, which relies upon the implementation of functionalities in day-to-day objects. Recently, some easy-cleaning products were developed, but they are add-on products to be applied on existing surfaces. The growing trend towards the increase of the elderly population indicates that the aging rate will more than duplicate in 2080 passing from 147 to 317 elderly people per 100 young people ¹ . Therefore, the decentralized health care needs and the use of the built environment (our habitat) as a space where the population tends to spend more time, plays a crucial role in the fight against isolation and in providing a greater and better quality of life.

[0003] Functional smart homes are a growing reality, which relies upon the implementation of functionalities in day-to-day objects. Easy-cleaning is a topic of huge scientific relevance in the last years encouraging the scientific community to make efforts to develop this type of products. Regarding all types of furniture and environments in a home, kitchen furniture is one of the major concerns, once it is exposed to an atmosphere that triggers que accumulation of dirt (mainly grease) and the appearance of pathogenic microbial contamination. Dirt comprises a mixture of substances which can be liquid (liquid soil - water, coffee, grease) or dry (dry soil - dust particles). Several parameters can influence the accumulation of dirt, such as material type, finishing agents and the type of dirt. Regarding liquid soil and according to Young's equation ² , when the surface tension of the liquid is lower than of the surface, there is a tendency to fouling. As such, easy-cleaning coatings should possess hydrophobic properties to be able to reduce the surface tension of the surface. Nevertheless, regarding the dry soil, the adherence to the surface depends on the adhesion forces (electrostatic and van-der-Waals forces) between the material's surface and surface of the dirt particles which are influenced also by the surface chemistry and the contact area. To reduce dry soil accumulation, anti-static surfaces are a good solution once they promote an easier removal of electrically charged particles. ²

[0004] There are several scientific studies and commercial products reported in the literature, whose objective is to improve surface cleaning processes and obtain antimicrobial properties. To improve surface cleaning properties, hydrophobic coatings ⁴ are generally used along with Si, ZnO or TiO2 nanoparticles (NPs), being this type of materials available commercially ⁵ - ⁶ . The application of coatings that provide micro-texture/roughness to the surface can induce antiadhesive and anti-static properties ⁷ These surfaces can be endowed with active antimicrobial properties ⁸ through the addition of growth-retarding agents or biocides to coatings, which promotes microorganism cell lysis, such as ZnO ⁹ and Ag ¹⁰ NPs and photocatalytic additives (eg TiOZ) ¹¹ . The commercial availability of functional furniture is limited, and, in this context, it is intended for hospital use or is not easily accessible to the common consumer.

[0005] These facts are disclosed in order to illustrate the technical problem addressed by the present disclosure.

G EN ERAL DESCRIPTION

[0006] As aspect of the present disclosure relates to the development of multidisciplinary solutions for an Active, Safe and Healthy Life, focusing on defining and optimizing a new concept of senior-friendly habitat. Included in which is the objective of developing the architectural "home space" design focused on the accommodation of users, and the development of functional furniture. To reduce time and efforts associated with cleaning, the present disclosure describes a coating composition to provide furniture surfaces with easy-cleaning and antimicrobial intrinsic properties to be applied during the production process.

[0007] In an embodiment, the present disclosure relates to the development of innovative and multifunctional modular furniture, with better cleaning and sanitizing properties through the application of a functional finish, with an emphasis on the exploration of eco-sustainable processes and materials and easy industrial implementation. This solution is also committed to increase the durability and long-term protection of the innovative product, without modifying other aesthetic parameters that are equally important for the consumer. [0008] The present disclosure is focused on liquid dirt, once it is one of the major concerns on kitchen furniture due to spills of grease and liquids. Once the kitchen cabinets doors are at 90° angle, it is important to assess the water and oil sliding angle and angular hysteresis. On a tilted surface, a droplet possesses a maximum contact angle before the droplet advances (advancing contact angle - 0 adv) and a minimum contact angle before the droplet recedes (receding contact angle 0 rec). The sliding angle is the tilting angle at which the gravitational force overcomes the lateral adhesion forces and causes the droplet to slide. The difference between the advancing contact angle and the receding contact angle it is denominated by angular hysteresis (A0= 0 adv- 0 rec).

[0009] Different water-based polyurethane (PU) dispersion can be used in the polymeric coating composition of the present disclosure, for instance, lk polyurethane dispersion, 2k polyurethane dispersion, anionic polyurethane dispersions, cationic polyurethane dispersions, non-ionic polyurethane dispersions, aromatic polyurethane dispersions and aliphatic polyurethane dispersions.

[0010] PU coatings can be divided into two main groups, namely into 1 and 2 pack systems (lk and 2k). The lk system basically contains a dispersed, fully reacted PU whilst a 2k system can contain partially reacted PU and unreacted monomers. Both systems can be solvent-based or waterborne.

[0011] The viscosity may be measured by different methods known in the art. In the present disclosure, the viscosity was measured through a Fungilab viscometer using L2 spindle and a velocity of 20 rpm at 23 °C.

[0012] An aspect of the present disclosure relates to a polymeric coating composition for wooden based furniture easy cleaning comprising:

61 - 99.8 % (w/wtotal) of a water based polyurethane dispersion;

0.1 - 10 % (w/wtotal) of at least one matting agent;

0.01 - 5 % (w/wtotal) of at least one antimicrobial agent.

[0013] Surprisingly, the polymeric coating composition of the present disclosure showed to be clean resistant, and it is able to maintain its performance after several cleaning cycles. Additionally, it showed improved results in terms of adhesion, uniformity of the coating, and final coating color coordinates in different substrates tested. It also showed to be resistance to damage by external forces.

[0014] In a preferred embodiment, the coating composition comprises 1-4% (w/w _to tai) of at least one matting agent. [0015] In a preferred embodiment, the matting agent is elastomeric silicone suspension; preferably an aqueous suspension of elastomeric silicone beads comprising epoxy functionality.

[0016] In an embodiment, the coating composition comprises

70 - 90 % (w/w _to tai) of a water based polyurethane coating, preferably 75 - 85 % (w/w _to tai);

1 - 4% (w/w _to tai) of at least one matting agent; preferably 2 - 3 % (w/w _to tai);

0.05 - 2% (w/w _to tai) of at least one antimicrobial agent; preferably 0.1 - 1 % (w/w _to tai).

[0017] In an embodiment, the coating composition further comprises at least one of the following components, preferably all,

0.1 - 5 % (w/w _to tai) of at least one defoamer agent;

0.1 - 5 % (w/w _to tai) of at least one hydrophobic agent;

1 - 10% (w/w _to tai) of a first glycol ether-based solvent;

1 - 10% (w/w _to tai) of a second glycol ether-based solvent;

0.05 - 3 % (w/w total) of at least one drier catalyst agent;

1 - 30% (w/w _to tai) of at least one isocyanate-based component.

[0018] In an embodiment, the coating composition comprises: at least one of the following components, preferably all,

0.5 - 2 % (w/w _to tai) of at least one defoamer agent, preferably 1 - 2 % (w/w _to tai);

1 - 3 % (w/w _to tai) of at least one hydrophobic agent, preferably 1 - 2 % (w/w _to tai);

3 - 6% (w/w _to tai) of a first glycol ether-based solvent, preferably 4 - 5 % (w/w _to tai);

1 - 5% (w/w _to tai) of a second glycol ether-based solvent, preferably 1 - 3 % (w/w _to tai);

0.1-1 % (w/w _to tai) of at least one drier catalyst agent, preferably 0.1 - 0.5 % (w/w _to tai);

4 - 10% (w/w _to tai) of at least one isocyanate-based component, preferably 6 - 8 % (w/w _to tai).

[0019] In an embodiment, the level of adhesion of the coating composition is equal to zero, measured using the procedure ISO 2409:2020 (Fifth edition, 2020-08) - Paints and varnishes — Cross-cut test.

[0020] In an embodiment, the viscosity of the coating composition ranges from 600-1500 mPa.s; preferably 900 - 1100 mPa.s measured on a Fungilab viscometer using a 500 mL glass beaker containing the coating composition up to its maximum capacity, with spindles L2, a rotation of 20 rpm, and a torque between 50 and 95%, at 23 °C

[0021] In an embodiment, the water based polyurethane dispersion is a lk aliphatic, fatty acid- modified and anionic polyurethane dispersion (e.g. Bayhydrol® UH 2874), preferably comprising a viscosity equal or below 1000 mPa.s at 23°C. [0022] In another preferred embodiment, the water based polyurethane dispersion is a lk aliphatic, anionic polyurethane dispersion containing polycarbonate (e.g., Bayhydrol UH 2606).

[0023] In a preferred embodiment, the coating composition is absent of titanium dioxide.

[0024] In an embodiment, the matting agent is selected from a list consisting of: elastomeric silicone suspension (e.g. Dowsil IE-3301), olive pit powder, naturally based wax dispersion (e.g. Ceridust 8091 VITA), beeswax, optical brighteners, silica nanoparticles, polymethylsilsesquioxane microbeads (e.g. E+540), aliphatic polyurethane matting agent (e.g. Decosphaera BIO 8 TR) or mixtures thereof. Preferably, the matting agent is elastomeric silicone suspension (e.g. Dowsil IE-3301).

[0025] In an embodiment, the antimicrobial agent is selected from consisting of: a mixture of 1,2-Benzisothiazol-3(2H)-One (BIT) and 2-Methyl-2H-lsothiazol-3-One (MIT) (e.g. Nuosept BM 11), vanillin, chitosan, titanium dioxide, quaternary ammonium compound, a mixture of 5 Chloro-2-Methyl-4-isothiazolin-3-one and 2-Methyl-4-isothiazolin-3-one (e.g. MERGAL® CM 1.5), or mixtures thereof. Preferably, the antimicrobial agent is a mixture of 1,2-Benzisothiazol- 3(2H)-One (BIT) and 2-Methyl-2H-lsothiazol-3-One (e.g. Nuosept BM 11).

[0026] In an embodiment, the defoamer agent is a VOC-free defoamer agent selected from a list consisting of: composition of polysiloxanes and hydrophobic solids in polyglycol (e.g. Byk 28), polypropylene glycol, mineral oils, vegetable oils, natural and synthetic waxes, or mixtures thereof. Preferably, the defoamer agent is a composition of polysiloxanes and hydrophobic solids in polyglycol (e.g. Byk 28).

[0027] In an embodiment, the hydrophobic agent is selected from a list consisting of: polyether modified hydroxy functional polydimethylsiloxane (e.g. Silclean 3720); organosilanes, preferably hexadecyltrimethoxysilane or trimethoxymethylsilan; fluorinated C6 hydrocarbons (e.g. Phobol CP-100; Addiguard C6/6003; Hexafor 6284); micronized PTFE-modified polyethylene wax (e.g. Ceraflour® 999); Capstone® (e.g. Capstone® ST200); beeswax; or mixtures thereof. In a preferred embodiment, the hydrophobic agent is polyether modified hydroxy functional polydimethylsiloxane (e.g. Silclean 3720).

[0028] In an embodiment, the first glycol ether-based solvent is selected from a list consisting of: dipropylene glycol methyl ether (e.g. Dowanol™ DPM), dipropylene glycol, 1,3-butylene glycol, 2-methylpentane-2,4-diol, or mixtures thereof. Preferably, the first glycol ether-based solvent is dipropylene glycol methyl ether (e.g. Dowanol™ DPM).

[0029] In an embodiment, the second glycol ether-based solvent is selected from a list consisting of: propylene glycol diacetate (e.g. Dowanol™ PGDA), dipropylene glycol methyl ether acetate, Dipropylene glycol methyl ether, or mixtures thereof. Preferably the second glycol ether-based solvent is propylene glycol diacetate (e.g. Dowanol™ PGDA).

[0030] In an embodiment, the drier catalyst agent is selected from a list consisting of: cobalt- free iron complex-based catalyst (e.g. Borchi OXY - Coat 1101), zirconium diketonate, dibutyltin dilaurate, or mixtures thereof. Preferably, the drier catalyst agent is cobalt-free iron complexbased catalyst (e.g. Borchi OXY - Coat 1101).

[0031] In an embodiment, the isocyanate-based component is selected from a list consisting of: hydrophilic aliphatic polyisocyanate based on pentamethylene diisocyanate (e.g. Bayhydur® eco 701-90), Aromatic blocked isocyanate (e.g. Meikanate TP-10), aliphatic blocked polyisocyanate (e.g. Imprafix® 2794), branched polymer with ether and urethane groups comprising crosslinking, blocked isocyanate groups (e.g. Desmocap® 11), ketone-aldehyde condensation resin (e.g. Tego® Variplus CA) or mixtures thereof. Preferably, the isocyanatebased component is hydrophilic aliphatic polyisocyanate based on pentamethylene diisocyanate (e.g. Bayhydur® eco 701-90).

[0032] Another aspect of the present disclosure relates to furniture comprising the coating composition herein described, preferably the furniture is kitchen furniture.

[0033] In an embodiment, the wet grammage of the coating composition in the furniture ranges from 70 g/m2 to 240 g/m2; preferably ranges from 100 g/m2 to 140 g/m2.

[0034] In an embodiment, the furniture material is a wood-based material, preferably with a curing basecoat selected from a list consisting of: polyurethane, UV (ultraviolet radiation coating), waterborne or polyester; more preferably polyurethane.

[0035] In an embodiment, the wood-based material is selected from a list consisting of: high density fiberboard (HDF), medium-density fibreboard (MDF) and three-dimensional fiberboard (3DF), or mixtures thereof.

[0036] Another aspect of the present disclosure relates to a method for obtaining the coating composition comprising the following steps: adding to the water based polyurethane dispersion, a defoamer agent, a hydrophobic additive, a first glycol ether-based solvent, a second glycol ether-based solvent, a drier catalyst agent, a isocyanate-based component, a matting agent and an antimicrobial agent; wherein each component is adding separately and sequentially, with a period of stirring of at least 5 minutes between each component addition and with a final period of stirring of at least 20 minutes after the last addition; preferably the stirring is performed at 700 rpm at 25 °C. [0037] It was surprisingly found that the composition of the present disclosure provides improved adhesion to wood-based subtracts with a polyurethane basecoat, and at the same time improved resistance to staining, namely by water, mineral oil, coffee and ethanolic solutions. Additionally, and of utmost importance, the polymeric coating of the present composition allows the easy cleaning of the furniture, due to their specific properties of sliding for hydrophilic liquids and also for lipophilic liquids. The composition herein described also showed to be resistant and able to maintain its performance after several cleaning cycles.

BRI EF DESCRI PTION OF THE DRAWINGS

[0038] The following figures provide preferred embodiments for illustrating the disclosure and should not be seen as limiting the scope of invention.

[0039] Figure 1: Images of the uncoated substrate (left) and of the substrate coated with Fl (right).

[0040] Figure 2: Optical microscopy images of the uncoated substrate, Fl, F2 and F3 coated samples' surfaces.

[0041] Figure 3: a) 2D representation of the difference between chromatic and non-chromatic colours and the different parameters used; b) 3D representation of the 3 parameters used to classify non-chromatic colours: .AL*, a*, and b*.

[0042] Figure 4: FTIR spectra of the uncoated substrate and of the samples coated with the Fl, F2 and F3 compositions.

[0043] Figure 5: Images of the mineral oil dragging marks on the surfaces of the nonfunctionalized substrate (left) and of the coated substrate (right).

[0044] Figure 6: Graphic representation of the culture growth (above) and of cell density and viability (bellow) of E. coli on the surface of the uncoated substrate (A), of the substrate coated with Fl (B) and of the substrate coated with F3 (C).

DETAILED DESCRIPTION

[0045] The present disclosure relates to a polymeric coating composition for wooden based furniture easy cleaning comprising a water based polyurethane dispersion, at least one matting agent and at least one antimicrobial agent. Furthermore, the present disclosure relates to a method to obtain said coating composition, and furniture comprising said coating composition. EXAMPLES

[0046] The selected substrate for the development of multifunctional furniture was a woodbased substrate with a polyurethane basecoat.

[0047] The coating composition comprises polyurethane-based formulations with 50% recycled content, functionalized with an eco-friendly matting agent and with a FDA approved antimicrobial additive.

[0048] For the testing of the antimicrobial properties, dry films of E. coli were used. In all normative procedures, reagents and materials used grades were those described.

Coating composition preparation

[0049] For the coating composition preparation, the water based polyurethane coating (Fl) was mixed using continuous mechanical agitation for 40 min at 700 rpm at room temperature, where the different components of Fl (VOC (volatile organic compound) -free defoamer, hydrophobic additive and cobalt-free drier) were added to the composition in four different steps, with a 5 min stirring in between and a final 20 min stirring before application. F2 and F3 were prepared in the same way as Fl, but before the final step of stirring, the matting agent (F2 and F3) and the antimicrobial agent (F3) were added.

[0050] In another embodiment, the preparation is divided in a first part (Part A) and in a second part (Part B). Part A comprises the water-based polyurethane dispersion, the VOC-free defoamer agent, the hydrophobic agent, the first glycol ether-based solvent, the drier catalyst and the water (Each component is adding separately and sequentially, with a period of stirring of at least 5 minutes). Part B comprises the mixture of the isocyanate-based component and the second glycol ether-based solvent. The coating composition is then finalized by adding the second part (Part B) to the first part (Part A).

[0051] In Table 1 are presented the respective compositions and quantities added.

Table 1. Composition of the developed coating composition Fl, F2 and F3.

Coating application on substrates

[0052] The coating composition was applied by spray. The spray coating application was performed on the polyurethane painted wood-based selected substrate (HDF, MDF, 3DF). Prior to spraying, all the samples were cleaned in a twostep process: a passage of compressed air to blow and passage of ethanol wet paper towel. The samples were placed between 10 cm and 15 cm distance from the spray gun, and the coating compositions Fl, F2 and F3 were applied until a thin and uniform layer with similar wet grammages (between 70 g/m ² and 240 g/m ² ) was achieved. All samples were dried using an IR tunnel oven set to 50 °C for 30 min. The samples were then left to rest for 8h.

[0053] In examples F5 and F6, prior the spray coating, the final formulation is filtered, preferably with a 125 pm mesh filter, to avoid the transference of aggregates or undispersed particles. A spray coating application gun was used, with the filter incorporated, with a diameterer between 1.2 to 1.5 mm, preferably 1.2 mm and a pressure between 2 and 4 bar, preferably 2 bar.

Optical Microscopy

[0054] The surface morphologic characterization of the uncoated substrate and of the coated substrates was performed on an optical microscope (LEICA DM 2500M) with an ocular magnification of lOx and recurring to the objective with a magnification of lOx (Figure 2).

[0055] Colour Coordinates Determination: The analysis was performed in a UV-VIS-NIR Spectrophotometer (Agilent - 5000 equipped with a DRA-2500 integrated sphere). The calculations followed the normative procedures in ASTM D 224405 (2005) Standard Practice for Calculation of Color Tolerances and Color Differences from Instrumentally Measured Color Coordinates; ASTM E 308 - 01 (2001) Standard Practice for Computing the Colors Of Objects by Using the CIE System; and ASTM C1510-01 (2012) - Standard Test Method For Color And Color Difference Of Whitewares By Abriged Spectrophotometry. The colour deviation results were presented and compared to the control wood-based substrate.

[0056] FTIR-ATR: attenuated total reflectance (ATR) Fourrier transform infrared (FTIR) spectroscopy (FTIR- 223 ATR) was performed to evaluate the chemical groups present at the surface of the coated substrates, in comparison to the uncoated substrate, using a Perkin Elmer Spectrum 100 Series spectrophotometer with a spectral range of 4000 cm' ¹ to 650 cm' ¹ and a resolution factor of 8 cm ¹ .

[0057] Adhesion Test: the adhesion of the functional finishing coating to the substrates in study was performed according to the normative procedure described in ISO 2409:2020 - Paints and varnishes — Cross-cut test. The level of adhesion of the coatings to the substrates was attributed according to the classification scale ranging from 0 to 5 (being 0 the maximum level of adhesion and 5 a coating with no adhesion). The level for approval in quality tests in Adhesion Test is a result of 0. [0058] Stain Resistance Test: the resistance of the coated substrates to staining by water, mineral oil, coffee and 48% ethanolic solution, compared to the performance of the uncoated substrates, was evaluated according to the procedure described in normative EN 12720-2009 - Furniture - Assessment of surface resistance to cold liquids. The level of stain resistance of the tested surfaces was attributed according to the classification scale ranging from 1 to 5 (being 5 the absence of stain and 1 a strong stain). The minimum level for approval in quality tests is stain resistance equal or superior to 4.

[0059] Water and Oil Sliding Angle: the water and oil sliding angle measurements of the surfaces were determined with a tensiometer (Attension Theta, Biolin Scientific) through the sliding angle method, with a water droplet volume of 20 pL, using the OneAttension software. The sliding angle measurements were performed on both coated and uncoated substrates. Sliding performance evaluation after washing cycles: 20 pL droplets of water and mineral oil are deposited on top of the flat surfaces (in horizontal position) and are left to rest for 30 s. After this period, the samples are placed in a 90° angle (vertical position) and the time the droplets take to slide over a 9 cm distance is registered. This procedure is performed on the samples with 0 cycles of cleaning 2.5 mL of water and 2.5 mL of mineral oil spilled on the surface, as well as on samples with at least 10 cycles of spillage and cleaning. The surface cleaning process was done by first passing a dry paper towel, followed by passing a water wet paper towel, and finalizing by passing a dry paper towel.

[0060] Antimicrobial Activity: for the evaluation of the antimicrobial activity of the developed coated materials, the samples were previously cut into 1.5 cm x 1.5 cm x 1 cm cubes, washed with water and cotton for the removal of surface contaminations, and disinfected under UV light. Upon this procedure, dry films of E. coli were put in contact with the coated and uncoated surfaces for 24 h. Upon this, the dry film was removed, and the number of cells adhered to the surface, as well as the cell viability and density where determined.

[0061] Viscosity determination: The viscosity of the Fl, F2 and F3 dispersions were determined at 23 °C on a Fungilab viscometer using L2 spindle and a velocity of 20 rpm.

[0062] The polyurethane-based compositions of the present disclosure (Fl, F2 and F3) comprises a viscosity between 600 mPa.s and 1500 mPa.s.

[0063] In an embodiment, the polyurethane-based compositions were applied on wood-based substrate representative of furniture with a polyurethane-based basecoat, and resulted in visually uniform finishes (Figure 1). [0064] For a more detailed analysis, the surface of the coated substrates and of the uncoated substrate were analysed by optical microscopy, having verified that the applied coatings appear to be uniformly distributed over their surface. Additionally, it is shown that the applied coatings also present some porosity in a similar way to the basecoat of the non-functionalized substrate, resulting from the arrangement of the polymer chains during the curing stage and even to the evaporation of the solvents (Figure 2).

[0065] Additionally, in relation to the characterization of the surface with coated substrates, it is also verified that they differ from each other in terms of gloss. The substrate coated with Fl has a higher gloss level than the other samples, while the substrates coated with F2 and F3, due to the integration of the matting agent, have a gloss level visually close to that of the substrate.

[0066] Since the original green colour of the wood-based substrate and all the coated samples have a Chroma value < 10, the method chosen to evaluate the colorimetric coupons was ASTM C1510-01 (2012). The non-chromatic colour variations are represented in Figure 3 b).

[0067] To understand if the application of the developed topcoats allowed the maintenance of the initial green colour of the sample, the colour coordinates of the coated substrates and the uncoated substrate were determined, as indicated in Table 2.

Table 2. Values of the different Colorimetric compounds analysed (ASTM C1510-01 (2012)), according to ASTM C1510-01 (2012) applied to a non-chromatic colour.

Sample

Uncoated substrate 6.76 ± 0.19

Substrate + Fl 6.49 ± 0.02 0.82 ± 0.26 -0.07 ± 0.10 -0.78 ± 0.22 1.13

Substrate + F2 6.65 ± 0.37 0.10 ± 0.24 0.07 ± 0.13 -0.38 ± 0.24 0.40

Substrate + F3 6.73 ± 0.05 0.27 ± 0.24 -0.14 ± 0.10 -0.36 ± 0.22 0.47

C*ab=Chroma; L*= Lightness; Aa*= Green, Red (-Aa*= greener, +Aa*= redder); Ab*= Blue, Yellow (-Ab*= bluer, +Ab*= yellower); (total colour difference between sample and standard).

[0068] Analysing the results shown in Table 2, the AL* value have a variation between +0.10 and +0.82. The higher Lightness value of the Substrate + Fl (+0.82) can be related with the absence of matting agent on the composition and the subsequent more brightness spotted simply, by observation. In other hand, F2 and F3 have a lower non-lightness variation when compared with uncoated substrate. The Aa* value represents the greener/redder variations. All the results are similar to the uncoated substrate and inside the standard deviation range. This proves the green colour similarity between the uncoated substrate and the other samples, and the transparency of the functional coating. The Ab* values are negative which indicates a slightly higher blue level when compared with the control. This variation is not relevant in terms of observation comparing the different samples. Finally, the value of AE* is bigger in Fl (1.13) and very similar for F2 and F3 (0.40 and 0.47 respectively). Fl had the higher colour deviations in comparison with the uncoated substrate, but the colour deviations achieved are not significant and the results could be acceptable in a quality control analysis.

[0069] Regarding the chemical characteristics of the surfaces, the uncoated substrate and the substrates coated with Fl, F2 and F3 were analysed by FTIR (Figure 4). Analysing the spectra obtained, the chemical similarity between the surfaces of the coated substrates and the basecoat of the uncoated substrate was proved, since they present the same spectral bands, including the spectral bands characteristic of polyurethanes, as mentioned by several works reported in literature ¹² - ¹³ - ¹⁴ - ¹⁵ . At 3315 cm ¹ can be perceived the stretch of the N-H bond of the amine, between 2850 cm ¹ and 2924 cm ¹ are present the spectral bands referent to the stretching vibrations of CF , between 1680 cm ¹ and 1719 cm ¹ is present the spectral band of the stretch of the C=O bond, at 1530 cm' ¹ is present the spectral band produced by the bending of the N-H, between 1220 cm' ¹ and 1250 cm' ¹ refers to the spectral band of stretching vibration of the C-N bond, and between 1050 cm' ¹ and 1071 cm' ¹ is present the spectral band of the stretching of the C-0 bonds of ether groups.

[0070] The chemical similarity of the coated samples to the uncoated substrate is a good indicative that the developed coatings present a good performance in terms of to the basecoat present in the substrate. To validate this, adhesion tests were performed according to the procedures described in ISO 2409:2020. Observing the results present in Table 3, it is possible to conclude that maximum level of adhesion is achieved.

[0071] One of the purposes of the present disclosure was to achieve a substrate with improved easy-cleaning properties through the ease of water and oil slippage and reduction of their trail, without the loss of stain resistance presented by the uncoated substrate (resistance values equal or higher than 4). Thus, the surfaces of the substrates coated with Fl, F2 and F3 were evaluated in accordance with EN 12720-2009. According to the results presented in Table 3, the coated substrates present high levels of resistance to staining by water, mineral oil, 48% ethanol solution and coffee, passing the quality criteria defined. [0072] Table 3. Values of the stain resistance level (EN 12720-2009), of the surfaces of the unfunctionalized substrate and of the substrates coated with Fl, F2 and F3.

[0073] All the samples have been analysed in terms of adhesion level (ISO 2409-2020), and all presented a classification of 0.

[0074] Regarding the improvement of water and mineral oil sliding, as well as the reduction of the trail created during sliding on the surface of the wood-based substrate, in order to reduce the cleaning frequency and effort required during the task, compositions Fl, F2 and F3 were developed to reduce the adhesive forces between the basecoat of the non-functionalized substrate and the compositions. This leads to an easy mobility and dragging of all/almost all of its volume during movement. In this sense, the surfaces of the non-functionalized substrate and the substrates coated with Fl, F2 and F3 were analysed in a tensiometer to determine the angular hysteresis and tilt angle, and the results obtained are presented in the Table 4.

Table 4. Values of the angular hysteresis and tilt angle of water drops of the surfaces of the unfunctionalized substrate and of the substrates coated with Fl, F2 and F3. n.d. - not determined

[0075] It was observed, in a first analysis and keeping the same conditions between tests, that it was not possible to measure the values of the water component in the case of the uncoated substrate, since the water drop does not slide with the applied slope. However, when the surface is functionalized (Fl, F2 and F3), there is a slip of water. These results, validate that the developed compositions decrease the adhesive forces between the substrate's surface and the liquid, thus promoting an easier and faster sliding of the water on the surface. For the mineral oil, the angular hysteresis and tilt angle were not possible to measure for the non-functionalized substrate, since the mineral oil droplet spreads out completely when placed on the surface of the sample, and thus it proved impossible to perform further comparisons with the functionalized samples. However, analysing Figure 5, it is evident that the functionalized surface presents an improvement on the performance of the surface properties compared to the nonfunctionalized substrate. The mineral oil dragging marks on the coated substrate's surface are almost non-existing in contrast with the severely oily surface of the non-functionalized substrate. Once more, this is indicative that the adhesive forces of the surface have been decreased with the developed coatings. In this sense, it is possible to conclude that easy- cleaning surfaces for water and oil have been achieved, which will promote the long-term maintenance of clean surfaces and help reduce the frequency and effort associated with its cleaning.

[0076] Aiming to determine if the improved sliding properties of the functionalized surfaces would remain during usage, a series of water and mineral oil spillage over the functionalized and non-functionalized surfaces, followed by its cleaning, were performed. In Table 5, are presented the results of the sliding performance of the tested surfaces.

Table 5. Values of the time needed for the sliding of 20 pL droplets of water and mineral oil to slide over 9 cm of the surfaces of the unfunctionalized substrate and of the substrates coated with Fl, F2 and F3 after 0 and 10 cycles of cleaning spilled water and mineral oil.

Time for water droplet Time for mineral oil

<j _am plp sliding/s droplet sliding/s

0 cycles 10 cycles 0 cycles 10 cycles

Uncoated .. .. .. ..

. No sliding No sliding 55.0 ± 3.3 60.0 ± 12.7 substrate

Substrate + Fl No sliding No sliding 22.3 ± 3.8 14.3 ± 0.4

Substrate + F2 11.7 ± 3.1 18.3 ± 4.4 13.7 ± 1.6 15.3 ± 0.4

Substrate + F3 10.7 ± 2.4 18.0 ± 4.67 17.7 ± 3.6 14.7 ± 1.1

[0077] Analysing the results presented in Table 5, it is possible to observe that the sliding behaviour for the water droplet after 10 cycles of usage and cleaning remains the same for the unfunctionalized sample and for the substrate coated with Fl (no sliding), whilst for the substrates coated with F2 and F3, the time for water sliding had a small increase, around 8 s. As for the sliding of the mineral oil droplets, the variations in the sliding time for each sample were not so significant, except for the substrate coated with Fl, which presented better sliding properties. Nevertheless, it is possible to conclude that, after 10 cycles of usage and cleaning, the functionalized surfaces still present significant improvements on their surface properties compared to the unfunctionalized sample, remaining easy to clean. Hence, it was demonstrated that the coating composition of the present disclosure is resistance to several cleaning cycles. [0078] In order to evaluate the anti-adhesive and antimicrobial properties of the functionalized surfaces against the non-functionalized substrate, samples of the non-functionalized substrate and of substrates coated with Fl and F3 were characterized in terms of culture growth and cell density/viability (Figure 6).

[0079] Analysing the culture growth results, it is possible to verify that the growth of the bacteria is favoured in the non-functionalized substrate and in the substrate coated with Fl, both of which are prone to the adhesion of microorganisms, while the substrate coated with F3 has an E. coli load 89% lower compared to the non-functionalized substrate. This behaviour is related with the angular hysteresis and tilt angle for water for the non-functionalized substrate and Fl coated substrate samples are higher than for the substrate coated with F3, showing a greater propensity for the adhesion of microorganisms. Regarding the viability and cell density results, it was found that the surfaces of the non-functionalized substrate and the F3 functionalized substrate do not show antimicrobial properties, since non-viable cells represent between 0.01% and 6% of the total number of adherent cells. However, the F3 coated substrate has 0.55 log (69%) fewer total E. coli cells than the unfunctionalized substrate. Based on this and the fact that this sample hinders the adhesion and growth of cultures of the bacteria, it is possible to conclude that the substrate coated with F3 has antimicrobial activity.

Additional information

[0080] Table 6 depicts examples F4-F6 of the composition of the present disclosure.

[0081] Table 6. Composition of examples F4-F6.

[0082] It was observed that the composition F5 of the present disclosure provides improved results. In formulation F5, the water-based polyurethane dispersion Bayhydrol UH 2874 (lk aliphatic, fatty acid-modified, anionic polyurethane dispersion) was substituted by Bayhydrol UH2606 ((lk aliphatic, anionic polyurethane dispersion containing polycarbonate). It was found that using a lk aliphatic, anionic polyurethane dispersion containing polycarbonate, it was obtained an improved performance in terms of coating yellowing. Additionaly, formulation F5 does not comprise TiCh, once it was verified that TiCh provides decreased performance in terms of stain resistance.

[0083] Examples F4 and F5 were tested regarding level of resistance to staining (EN 12720- 2009), the level of adhesion (ISO 2409), time for sliding of water and mineral oil drops and the antimicrobial activity. Tables 7-8 resumes the results obtained. Table 7. Results with example 4 and example F6.

PES: Polyethersulfone

PU: Polyurethane

Tables 8. Results with example F4 and example F6. [0084] Table 9 provides sliding results of water and mineral oil droplets on samples coated with example F6 and control (without coating), wherein the substrate is grey MDF (PU paint).

[0085] Table 9.

[0086] Table 10 provides values of the surface resistance level (IOS-M AT-006 procedure, based on the EN 12720:2009 test method) and the force required in the Hamberger Hobel test (IOS- TM-0002 Test method for surface resistance) of samples coated with example F6.

[0087] The results herein discussed showed that the coating composition of the present disclosure provides improved results concerning surface resistance to staining by different liquids, in particular aqueous solutions (water and coffee) as well as mineral oil and ethanolic solutions, in different substrates (as depicted in Table 8). Additionally, it showed improved results in terms of adhesion, uniformity of the coating, and final coating colour coordinates in the four different substrates tested. It also showed to be resistance to damage by external forces.

[0088] The present disclosure shows that the developed coating compositions allowed to improve the surface properties of the wood-based substrate, doting them with easy-cleaning and antimicrobial properties, without prejudice of its already good stain resistance performance. These new coated substrates allow a faster sliding of water and mineral oil over the surfaces, with almost inexistent dragging marks, allowing to achieve a clean surface with no effort. Furthermore, the coating composition F3 presents an active antimicrobial activity which will decrease the growth of E. coli colonies, reducing the risk of related diseases.

[0089] The term "comprising" whenever used in this document is intended to indicate the presence of stated features, integers, steps, components, but not to preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0090] The disclosure should not be seen in any way restricted to the embodiments described and a person with ordinary skill in the art will foresee many possibilities to modifications thereof. The above described embodiments are combinable.

[0091] Where ranges are provided, the range limits are included. Furthermore, it should be understood that unless otherwise indicated or otherwise evident from the context and/or understanding of a technical expert, the values which are expressed as ranges may assume any specific value within the ranges indicated in different achievements of the invention, at one tenth of the lower limit of the interval, unless the context clearly indicates the contrary. It should also be understood that, unless otherwise indicated or otherwise evident from the context and/or understanding of a technical expert, values expressed as range may assume any subrange within the given range, where the limits of the sub-range are expressed with the same degree of precision as the tenth of the unit of the lower limit of the range.

[0092] The following dependent claims further set out particular embodiments of the disclosure.

[0093] This work was co-financed by the Operational Program for Competitiveness and Internationalization (COMPETE 2020), under the PORTUGAL 2020 Partnership Agreement, through the European Regional Development Fund (ERDF). REFERENCES

1. INE, 2017

2. Klinkhammer et al., "Structured textile surfaces for easy-to-clean properties towards dry soil", Materials Today: proceedings. 2017. Vol. 4. Pages S101-S106.

3. Wooh Sanghyuk et al. "Silicone Brushes: Omniphobic Surfaces with Low Sliding Angles", Angewandte Chemie International. 2016. Vol 55. Pages 6822-6824.V. Anand Ganesh et al., "A review on self-cleaning coatings", Journal Materials Chemical. 2011

4. NASIOL. [Online], Available on: https://www.nasiol.com/wood-waterproof-nano- coatings/

5. DRYWIRED. [Online], Available on: https://drywired.com/wood-shield-hydrophobic- coating/

6. Fu & Yuan, "Electricity functional composite for building construction". Advanced High Strength Natural Fibre Composites in Construction. 2017

7. A. Kandelbauer & P. Widsten, Progress in Organic Coatings, 65. Pages 305-313. 2009

8. Nosal & Reinprech, "Anti-bacterial and Anti-mold Efficiency of ZnO Nanoparticles Present in Melamine-laminated Surfaces of Particleboards". BioResources 12. 2017.

9. Nosal & Reinprech, "Anti-bacterial and Anti-mold Efficiency of Silver Nanoparticles Present in Melamine-laminated Surfaces of Particleboards". BioResources 14. 2019

10. V. Jaskova et al., "TiO2 and ZnO Nanoparticles in Photocatalytic and Hygienic Coating". International Journal of Photoenergy (2013) 795060

11. Caddeo et al., "Collagen/Polyurethane-Coated Bioactive Glass: Early Achievements Towards the Modelling of Healthy and Osteoporotic Bone", Bioceramics, 631. 2014

12. Asefnejad et al., "Manufacturing of biodegradable polyurethane scaffolds based on polycaprolactone using a phase separation method: Physical properties and in vitro assay", International Journal of Nanomedicine, 6. Pages 2375-2384. 2011.

13. Mohammadi et al., "Synthesis and investigation of thermal and mechanical properties of in situ prepared biocompatible Fe3O4/polyurethane elastomer nanocomposites", Polymer Bulletin, 2014.

14. Saad and Zubir, "Palm Kernel Oil Polyol-based Polyurethane as Shape Memory Material: Effect of Polyol Molar Ratio", Journal of Physical Science, 30. Pages 77-89. 2019.