Surface covering with an ultraviolet (UV) curable surface coating

Abstract

A surface coating is provided. The surface coating includes a laminated panel having a top layer and a UV-curable surface coating applied to the laminated panel. The UV-curable surface coating has a composition comprising oligomers, monomers, a photoinitiator, abrasion-resistant particles, and antimicrobial additives.

Description

[0001] Related applications This application is a divisional application of the invention patent application filed on June 1, 2017, with international application number PCT / CN2017 / 086822, national application number 201780091478.1, and entitled "Surface Cover with Ultraviolet (UV) Curable Surface Coating". Technical Field

[0002] The present invention generally relates to a surface covering, and more specifically to a surface covering having an ultraviolet (UV) curable surface coating. Background Technology

[0003] Luxury vinyl ceramic tiles (“LVT”) with polyvinyl chloride (“PVC”) as the main component are well known. Furthermore, the use of UV-curable surface coatings on LVT surface covers is also well known, as these coatings offer excellent surface properties in terms of stain and chemical resistance, gloss retention, scratch resistance, and cleanability. However, the known cost and brittleness of UV-curable surface coatings have limited their widespread application. Typically, known UV-curable surface coatings are applied only 1-2 mils thick on the outermost layer of the surface cover. Wear-through of these UV-curable surface coatings is always a concern for manufacturers, especially in commercial and industrial environments, before the end of the surface cover's entire service life. Therefore, there is a strong need to improve the abrasion resistance of UV-curable surface coatings to wear caused by pedestrian traffic and floor scrubbing during routine cleaning and maintenance.

[0004] In many cases, UV-curable surface coating systems also include antimicrobial and / or fungicidal agents to prevent the growth of various bacteria, fungi, and algae on the surface cover. However, adding antimicrobial additives to UV-curable surface coatings is expensive, typically costing several hundred dollars per pound. Therefore, the cost of using large or high concentrations of these additives in most products is prohibitive. Nevertheless, since inhibiting microbial growth and presence is expected to maintain the floor's entire lifespan, UV-curable surface coatings with antimicrobial additives possessing excellent abrasion resistance and durability are needed to achieve long-term effectiveness in inhibiting microbial growth. Summary of the Invention

[0005] Therefore, the present invention was designed in view of the above-mentioned problems to provide a surface covering having a UV-curable surface coating comprising an antimicrobial additive. More specifically, the surface covering comprises a laminated panel having a top layer and a UV-curable surface coating applied to the laminated panel. The UV-curable surface coating has a composition comprising oligomers, monomers, photosensitizing initiators, abrasion-resistant particles, and antimicrobial additives. Detailed Implementation

[0006] The following is a general description of various exemplary embodiments of the invention. Since describing every possible embodiment is impractical, if not impossible, this description should be interpreted as merely exemplary and does not describe every possible embodiment. It should be understood that any feature, characteristic, component, composition, ingredient, product, step, or method described herein may be deleted, replaced in whole or in part with any other feature, characteristic, component, composition, ingredient, product, step, or method described herein, or combined with them. Many alternative embodiments may be implemented using present technology or technology developed after the filing date of this patent, and these alternative embodiments should still fall within the scope of the claims. All publications and patents referenced herein are incorporated herein by reference.

[0007] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In case of any conflict, the definitions included herein shall prevail. Furthermore, unless the context otherwise requires, singular terms shall include plural terms, and plural terms shall include singular terms. For all purposes, all publications, patents, and other references mentioned herein are incorporated herein by reference in their entirety.

[0008] Unless otherwise stated, when the following abbreviations are used in this document, they have the following meanings: As used herein, the terms “comprises,” “comprising,” “includes,” “including,” “has,” “having,” “contains,” or “containing,” or any other variations thereof, shall be understood to mean that the stated integers or groups of integers are included, but not excluded any other integers or groups of integers. For example, a composition, mixture, process, method, article, or apparatus that comprises a list of elements is not necessarily limited to only those elements, but may include other elements not expressly listed, or other elements inherent to such composition, mixture, process, method, article, or apparatus. Furthermore, unless expressly stated to the contrary, “or” means inclusive “or” rather than exclusive “or.” For example, any of the following makes condition A or B satisfied: A is true (or exists) and B is false (or does not exist), A is false (or does not exist) and B is true (or exists), and both A and B are true (or exist).

[0009] Furthermore, the indefinite articles “a” and “an” preceding the elements or components of the invention are intended to be non-limiting in terms of the number of instances, i.e., the presence of elements or components. Thus, “an” or “a” should be understood to include one or at least one, and the singular form of an element or component also includes the plural, unless the quantity clearly implies the singular.

[0010] The terms “invention” or “the present invention” as used herein are non-limiting terms and are not intended to refer to any single embodiment of a particular invention, but rather to include all possible embodiments described in this application.

[0011] When referring to numerical values ​​or ranges, the terms "about" and "approximately" are intended to include values ​​resulting from experimental errors that may occur during the measurement. Concentration, amount, and other numerical data may be given in the form of ranges herein. It should be understood that such range forms are used merely for convenience and brevity and should be flexibly interpreted to include not only the numerical values ​​explicitly listed as range limits, but also all individual numerical values ​​or subranges contained within that range, as if each numerical value and subrange were explicitly listed. For example, a weight range of about 1 wt% to about 20 wt% should be interpreted to include not only the explicitly listed concentration limits of 1 wt% to 20 wt%, but also individual concentrations such as 2 wt%, 3 wt%, 4 wt%, and subranges such as 5 wt% to 15 wt%, 10 wt% to 20 wt%, etc.

[0012] An exemplary floor panel comprises a laminated profile prepared from a laminated polymer component and a coating. Specifically, the floor panel comprises a UV-curable surface coating according to the present invention.

[0013] Each floor panel is made of a laminated polymer component (including vinyl) forming several layers. In the illustrated embodiment, the total thickness of each floor panel is approximately 4-6 mm. However, floor panels with one or more layers can also be prepared, each layer having a different thickness. The composition of the floor panel can also vary, and floor panels can be made of various materials, including but not limited to polymers, ceramics, metals, organic materials, etc.

[0014] An exemplary floor panel is prepared as a laminate having a top layer of flexible polymer sheet, an intermediate layer of flexible polymer material, a base layer made of a more rigid polymer material, and an ultraviolet (UV) curable surface coating applied to its surface.

[0015] As shown, each of the layers has a different thickness. However, layers of equal thickness are also possible. The thickness, layering, and overall floor panel fabrication will conform to the preferences of the finished product (including dimensions). This fabrication is not limited to a particular design but incorporates novel design features described in the following paragraphs.

[0016] According to the present invention, a floor panel that can be shaped into a square or rectangle has four sides, wherein each side is connected by an interior angle of 90° (right angle). Additionally, the floor panel includes a top side and a bottom side. In the illustrated embodiment, the top side is prepared from a top layer, and the bottom side is prepared using a base layer. A UV-curable surface coating according to the present invention is then applied to the top layer to impart excellent scratch resistance and slip resistance, as well as long-lasting antimicrobial properties.

[0017] The exemplary floor panel is fabricated from various laminated components. In the illustrated embodiment, the top layer is fabricated with three components: an abrasion-resistant layer and a decorative layer, the decorative layer having printed features. Any component, such as the abrasion-resistant layer or the decorative layer, can have a texture to enhance the features of the floor panel structure.

[0018] In the illustrated embodiment, the decorative layer is configured with a printed pattern, the underside of which is bonded to the intermediate layer, with the printed pattern facing away from the base layer. The top layer features graphic and textured embossing and can be prepared to match any print or even mimic the characteristics of genuine metamorphic rocks.

[0019] In the illustrated embodiment, the top layer also includes a transparent abrasion layer. This abrasion layer can be made of polyvinyl chloride or other polymeric materials such as polyolefins, thermoplastic polyurethane (TPU), or ethylene vinyl acetate (EVA). The abrasion layer protects the decorative layer. Because the abrasion layer is transparent or clear, any aesthetic printing on the decorative layer is visible through it. While the thickness can vary, the abrasion layer can range from 0.1 to 1.0 mm. Typically, the thickness of the abrasion layer and the total thickness of the product are determined by the customer; the thickness of the abrasion layer has a significant impact on the overall floor paneling structure and the base coat formulation used.

[0020] The decorative layer can be used to provide printed graphics for floor paneling, enhancing its aesthetics. Additionally, based on its material composition, the decorative layer can provide material properties that neither the top layer nor the base layer can offer. In this embodiment, the decorative layer can be a decorative layer with a printed design on its top surface. The thickness of the decorative layer can vary. However, in the illustrated embodiment, the decorative layer is prepared to have a thickness of approximately 0.07 mm. Although the top layer is located above the intermediate layer, it is transparent, allowing easy visibility of any printed patterns on the top surface of the intermediate layer.

[0021] During the manufacturing process, the top layer can be textured to enhance the feel of the floor paneling. Therefore, if the top layer is prepared with a printed pattern and textured surface, the floor paneling will have the look and feel of genuine ceramic or metamorphic rock flooring. The embossed surface texture on the clear abrasion layer can be perfectly aligned with the printed decorative layer underneath to enhance the authenticity of the design. This is known in the industry as "embossed in register."

[0022] According to the present invention, the intermediate layer is made of a single layer of high-density plastic. However, to meet the requirements of preferred performance, the intermediate layer can be prepared from a homogeneous blend of polyvinyl chloride (resin) and other material additives (e.g., cork particles or glass fibers). In the illustrated embodiment, the intermediate layer is connected to the top layer and the base layer.

[0023] Because the interlayer can comprise a homogeneous blend of polyvinyl chloride (with high density) and material additives, the floor panel can meet preferred material properties, such as improved rigidity, strength, thermal conductivity, resilience, and noise reduction. The thickness of the interlayer can vary. However, in the illustrated embodiment, the interlayer is prepared to have a thickness ranging from 1.5 to 2.7 mm.

[0024] The subfloor is also optional and is made of a single layer of high-density plastic. The subfloor serves as a backing layer. Furthermore, the subfloor can maintain a connection with adjacent floor panels or existing flooring. Therefore, the floor panels can include a fastening source, which can be a pre-applied adhesive prepared on the underside of the subfloor. Alternatively, the fastening source can be a locking system on the side of the floor panel, which can allow the connection of several floor panels to be a floating installation.

[0025] Additionally, the subbase can be configured to balance the top layer, thereby substantially preventing warping of the floor paneling. While the subbase thickness can vary, it is appropriately set to a thickness ranging from 0.3 to 2.5 mm. The subbase can be prepared from a variety of materials, including but not limited to polyvinyl chloride, polyolefins, thermoplastic polyurethane (TPU), or ethylene vinyl acetate (EVA). This composition will depend on the intended application of the floor paneling.

[0026] In the illustrated embodiment, the floor paneling is prepared using a known hot-pressing manufacturing process. The durable abrasion-resistant layer and the decorative layer can be pre-bonded before these layers are properly positioned on top of each other and then bonded together using heat and pressure.

[0027] While the layering and size of the floor paneling are matters of choice, the appropriate thickness for the top, middle, and base layers can be, for example, 4-6 mm.

[0028] The typical process for manufacturing each layer is as follows: PVC powder and other material additives are added together and mixed thoroughly in an internal mixer. The mixture is then heated to a temperature of 150-215°C to produce a hot melt. The melt is then processed through a calendering mill heated to a similar temperature. The shearing and mixing action on the calendering roll surface plasticizes the melt and produces a polymer sheet with a controlled thickness. The thickness of the polymer sheet is controlled by adjusting the gap between the calendering rolls. The calendered sheet is then cooled and collected on a reel.

[0029] A typical process for manufacturing laminated profiles for flooring panels involves compressing the layers under heat and pressure with an embossed sheet having a desired texture that typically mimics the design of natural wood, ceramic, stone, slate, or brick.

[0030] In an exemplary embodiment, the laminated profiles of the floor paneling can be prepared by laminating them together in the following sequence: (1) One or more base layers; (2) Intermediate layer; (3) A decorative layer having a printed film; and (4) Transparent anti-wear layer.

[0031] Place the embossed sheet on top of the assembled stacked layers. Then heat the stacked layers to approximately 130°C-150°C and apply a pressure of approximately 3-5 MPa through the embossed sheet for approximately 20-30 minutes. Then cool the press to 30°C-50°C and remove the laminated profile of the floor panel.

[0032] In addition, the laminated profile is cooled for several hours, and then a UV-curable surface coating is applied to the top side surface of the floor panel. The coating process will be described below.

[0033] According to the present invention, a UV-curable surface coating comprises an exemplary composition having oligomers, monomers, a photoinitiator, abrasion-resistant particles, and antimicrobial additives. The amounts of the composition components are expressed as weight percentages (“wt%”).

[0034] In an exemplary embodiment, the oligomer is an acrylate resin. Specifically, the oligomer may consist of any of the following resins: (a) urethane acrylate oligomer, (b) epoxy acrylate oligomer, (3) polyester acrylate oligomer, or (4) polysiloxane acrylate oligomer.

[0035] Oligomers essentially contribute to specific properties of the finished product. For example, acrylate urethane crosslinks to form a tough yet flexible film that exhibits good abrasion and scratch resistance, while acrylate epoxy resins transform into a harder coating that provides strong adhesion to floor coverings and enhances resistance to chemical stains.

[0036] In an exemplary embodiment, the ultraviolet (UV) curable surface coating composition comprises about 40 to about 70 wt% of an oligomer. In another exemplary embodiment, the oligomer is about 50 to about 70 wt%. In yet another embodiment, the oligomer is about 55 to about 65 wt%. In yet another embodiment, the oligomer is about 40 to about 60 wt%. In yet another embodiment, the oligomer is about 44 to about 55 wt%.

[0037] Many oligomeric resins are proprietary to resin manufacturers for coating formulations. Typically, urethane acrylate oligomers are prepared based on the principle of diisocyanate addition polymerization. The isocyanate groups from the urethane react with polyester or polyether hydroxyl-functionalized acrylates to form a polymer structure. Due to the versatility of isocyanate compounds and the wide selection of polyol materials, numerous oligomers can be developed to meet the needs of coating developers. For flooring applications, aliphatic isocyanates such as 1,6-hexanediamine (HAD) are preferred due to the requirement for light stability. The Sartomer / Arkema Group offers a wide range of urethane acrylate oligomers to choose from. For example, CN9001NS is designed for coatings requiring good weather resistance and adhesion; CN9007NS imparts abrasion resistance and flexibility.

[0038] In exemplary embodiments, the monomer is a monofunctional, difunctional, or multifunctional monomer. The monomer essentially contributes to specific properties of the finished product. For example, the monomer controls the viscosity and curing rate of a UV-curable surface coating. The monomer can crosslink with oligomers.

[0039] Monomers can include monofunctional monomers such as acrylic acid, N-vinyl-2-pyrrolidone, isobornyl acrylate and esters of acrylic acid, as well as methacrylic acid derivatives. Monofunctional monomers are used to reduce viscosity to compensate for certain viscous oligomers in UV-curable surface coatings. Furthermore, monofunctional monomers promote adhesion to non-porous surfaces of floor paneling substrates and impart UV-curable surface coatings.

[0040] Monomers can include bifunctional monomers, such as tripropylene glycol diacrylate (TPGDA), hexanediol diacrylate (HDDA), dianol diacrylate (DDA), neopentyl glycol diacrylate (NPGDA), hexamethylene diacrylate, and 1,4-butanediol diacrylate (BDDA). Bifunctional monomers can be used because of their high reactivity. Additionally, bifunctional monomers provide toughness and strong adhesion, and are good solvents for oligomers.

[0041] Monomers can include trifunctional monomers, such as trimethylolpropane triacrylate (TMPTA) or pentaerythritol triacrylate (PETA). Trifunctional monomers can be used because they have higher viscosity and extremely high reactivity. Trifunctional monomers provide a higher crosslinking density for UV-curable surface coatings, which improves their hardness and abrasion resistance.

[0042] In an exemplary embodiment, the UV-curable surface coating may comprise about 15 to about 55 wt% of one or more monomers. In an exemplary embodiment, the monomer is about 25 to about 40 wt%. In yet another embodiment, the UV-curable surface coating composition comprises about 25 to about 35 wt% of a first monomer and about 1 to about 5 wt% of a second monomer. In yet another embodiment, the UV-curable surface coating composition comprises about 15 to about 25 wt% of a first monomer and about 5 to about 15 wt% of a second monomer. In yet another embodiment, the UV-curable surface coating composition comprises about 15 to about 25 wt% of a first monomer, about 5 to about 15 wt% of a second monomer, and about 1 to about 5 wt% of a third monomer.

[0043] Polymerization can be significantly accelerated using various initiators. According to the present invention, a photoinitiator is used in the radiation curing process of a UV-curable surface coating. When the UV-curable surface coating is exposed to UV light, free radical intermediates are formed, and these free radicals react with unsaturated groups on the oligomers and monomers to initiate polymerization. At the end of polymerization, the UV-curable surface coating becomes a solid three-dimensional matrix.

[0044] In an exemplary embodiment, the photosensitizer may be benzophenone, benzophenone derivatives, benzoin, benzoin derivatives, acetophenone, acetophenone derivatives, or aromatic ketone-amine systems, such as hydroxycyclohexylphenyl ketone.

[0045] In an exemplary embodiment, the UV-curable surface coating may include about 1 to about 20 wt% of one or more photoinitiators. In an exemplary embodiment, the photoinitiator is about 1 to about 10 wt%. In yet another embodiment, the UV-curable surface coating composition includes about 1 to about 10 wt% of a photoinitiator and about 1 to about 10 wt% of a second photoinitiator. In still another embodiment, the UV-curable surface coating composition includes about 1 to about 5 wt% of a first photoinitiator and about 1 to about 5 wt% of a second photoinitiator.

[0046] According to the present invention, abrasive wear-resistant particles are used to provide abrasion resistance to the top surface of floor covering 1. Specifically, according to the present invention, the abrasive wear-resistant particles are coarse-grained or single-crystal mineral abrasive particles.

[0047] In an exemplary embodiment, the abrasive wear-resistant particles comprise silicon carbide (SiC) particles. Silicon carbide (SiC) particles offer benefits for UV-curable surface coatings, including low density, high strength, low coefficient of thermal expansion, high thermal conductivity, good electrical properties, high decomposition temperature (~4530°F), oxidation resistance, and corrosion resistance (i.e., alkali and acid resistance). Since silicon carbide (SiC) is the third hardest material after diamond and boron carbide, the use of silicon carbide (SiC) particles in UV-curable surface coatings greatly facilitates wear-resistant applications.

[0048] When a UV-curable surface coating is exposed to UV light, a cross-linking reaction occurs, the temperature of the UV-curable surface coating rises, and the cured UV-curable surface coating shrinks. Therefore, using silicon carbide (SiC) particles minimizes the shrinkage of the UV-curable surface coating and reduces upcuring when applied to floor panels.

[0049] In an exemplary embodiment, the UV-curable surface coating comprises silicon carbide (SiC) particles, wherein 50% of the silicon carbide (SiC) particles have a particle size of less than 45 μm. In another exemplary embodiment, the UV-curable surface coating comprises silicon carbide (SiC) particles, wherein 90% of the silicon carbide (SiC) particles have a particle size of less than 45 μm.

[0050] In an exemplary embodiment, the ultraviolet (UV) curable surface coating composition comprises about 1 to about 20 wt% silicon carbide (SiC) particles. In an exemplary embodiment, the silicon carbide (SiC) particles are about 5 to about 15 wt%.

[0051] The use of antimicrobial additives in UV-curable surface coatings is to maintain the cleanliness and hygiene of floor panels, as these additives inhibit the growth of a variety of microorganisms, reducing bacterial infections and other related diseases. A few effective antimicrobial additives are available on the market, such as silver-based materials. Although the efficacy of silver-based antimicrobial agents against many bacteria has been well-proven, concerns about the carcinogenicity of silver as a heavy metal have driven consumers away from using it as a means of combating bacteria. Therefore, according to the present invention, a UV-curable surface coating composition includes an antimicrobial additive composition to impart antimicrobial properties to the UV-curable surface coating. The antimicrobial additive composition includes an amount of an antimicrobial agent, such as N-butyl-1,2-benzisothiazolin-3-one, commonly known as butyl-BIT (BBIT), and commercially available under the trade name VANQUISH from Avecia Chemical. Those skilled in the art will understand that other known antimicrobial agents may be used, including alkyl dimethyl saccharin ammonium, 2-pyridinyl thiol-1-zinc oxide, 10,10'-oxobisphenoxarium (OBPA), 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOIT), and any mixture thereof.

[0052] N-Butyl-1,2-benzisothiazolin-3-one is an organic type of antimicrobial / antifungal additive that exhibits excellent control over a wide range of bacterial, fungal, and algal organisms, thus preventing unpleasant odors and aesthetic problems such as stains or mold on floor surfaces. N-Butyl-1,2-benzisothiazolin-3-one can be applied as a liquid and is readily mixed with UV-curable surface coatings. N-Butyl-1,2-Benzisothiazolin-3-one has shown efficacy against a variety of fungi (such as Phona violacea, Aureobasidium pullulans, Cladosporium cladosoroides, Chaetomium globosum, Cladosporium herbarum, etc.) and bacteria (such as Bacillus cereus, Bacillus subtilis, Enterococcus faecalis, Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, and many other bacteria).

[0053] Considering the abrasion resistance and scratch resistance of UV-curable surface coatings, other additives in the composition, such as silicon carbide (SiC) particles, improve the longevity of the hygienic effect.

[0054] In an exemplary embodiment, the UV-curable surface coating composition includes about 0.05 to about 1.0 wt% of an antimicrobial additive. In an exemplary embodiment, the antimicrobial additive is about 0.1 to about 0.5 wt%.

[0055] In an exemplary embodiment, the UV-curable surface coating may include one or more additives, such as wetting agents, dispersants, defoamers, and matting agents. Silica matting agents may also be used to control the gloss of the UV-curable surface coating. Because both matting agents and abrasive particles are relatively heavy, the preparation of the UV-curable surface coating includes a dispersion process using a selected surfactant.

[0056] In an exemplary embodiment, the UV-curable surface coating composition comprises about 5 to about 20 wt% of an additive. In an exemplary embodiment, the UV-curable surface coating composition comprises about 5 to about 15 wt% of a first additive and about 1 to about 3 wt% of a second additive. In an exemplary embodiment, the UV-curable surface coating composition comprises about 5 to about 15 wt% of a first additive, about 1 to about 3 wt% of a second additive, and about 1 to about 3 wt% of a third additive.

[0057] An exemplary coating method for applying a UV-curable surface coating to floor panels will be described.

[0058] A heterogeneous 5.0mm floor panel is provided, comprising a transparent protective layer (0.5mm) 12, a decorative layer with a printed film (0.07mm), an intermediate layer (1.5mm), optional fiber glass scrim, an intermediate base layer (1.5mm), and a bottom base layer (1.5mm).

[0059] The layers are laminated in a hot press under heat and pressure for a sufficient time to bond each individual layer into a fully bonded, inseparable floor panel. The floor panel is then treated with a UV-curable surface coating according to the invention.

[0060] In an exemplary embodiment of the invention, the UV-curable surface coating is a two-coat system applied to a floor panel, using a first coating having a composition different from the second coating. The first coating of the UV-curable surface coating is applied and cured at a lower energy to form stage B of the curing process. A second high-performance coating is then applied on top of the first coating system and cured at sufficient energy to fully cure the combined two coatings.

[0061] Exemplary applications of dual-coat systems for UV-curable surface coatings are as follows: (1) Maintain the temperature of the first coating of the UV-curable surface coating at 30°-40°C; (2) The first coating is then pumped into a reservoir at the center of the roller coater; (3) Set the gap between the two rollers to measure the application rate to apply a coating weight of 9-10 g / m², and the amount of coating is equal to 12-13 μm.

[0062] (4) Place the floor panel on the conveyor and feed it through the first coating machine so that the top surface of the floor panel comes into contact with the coating rollers that apply the first coating to the top surface of the floor panel.

[0063] (5) The conveyor transports the floor panel (with the first coating applied) to the first ultraviolet (UV) curing chamber. The first UV curing chamber includes four sets of UV lamps, each capable of emitting a light intensity of up to 250 watts per centimeter.

[0064] (6) The light intensity is set to a medium to low level, therefore the UV curing energy is set to 300 millijoules / cm², which is required for B-stage curing. 2 .

[0065] (7) After the first coating has partially cured, the floor panel is transported by a conveyor belt to the second coating machine, and the second coating is applied to it.

[0066] (8) Based on performance requirements, the weight of the second coating is 9-18 grams per square meter.

[0067] (9) The conveyor then transports the floor panel (with the second coating applied) to the second UV curing chamber. The second UV curing chamber comprises four sets of UV lamps, each capable of emitting a light intensity of up to 250 watts per centimeter. The light intensity is set higher than that of the first UV curing chamber, and therefore the UV curing energy is set to approximately 700 millijoules or more. The combined curing energy of the first and second curing chambers is approximately 1000 millijoules.

[0068] Exemplary implementations of a two-coat system for ultraviolet (UV) curable surface coatings will now be described through the following examples.

[0069] Example I Table 1 discloses an exemplary embodiment of the first coating of the UV-curable surface coating according to the present invention. The first coating is the base coat of the UV-curable surface coating in a two-coat system.

[0070] Table 1 The exemplary curing conditions for the first coating are as follows: Viscosity in cps at 35°C: 800-1200 cps; Density: 1.09 g / mL at 25°C; Film thickness (micrometers): 13-25 micrometers; and Curing energy: 250-300 millijoules / cm 2 .

[0071] Table 2 discloses an exemplary embodiment of a second coating of the UV-curable surface coating according to the present invention. The second coating is the top coating of the UV-curable surface coating in a two-coat system.

[0072] Table 2 The exemplary curing conditions for the second coating are as follows: Viscosity in cps at 35°C: 800-1200 cps; Density: 1.18 g / mL at 25°C; Film thickness (micrometers): 13-25 micrometers; and Curing energy: 600-800 millijoules / cm 2 .

[0073] The surface properties of an exemplary embodiment of the dual-coating system for UV-curable surface coatings of Example 1 will now be described in detail using the following tables.

[0074] Table 3 shows the results of measuring surface properties for an exemplary embodiment of the UV-curable surface coating according to the present invention in Example 1. Specifically, Table 3 discloses the results of the standard test method for chemical resistance of resilient flooring provided by ASTM F925-13. Chemical reagents were placed on the surface of the test samples of Example 1 for 60 minutes, followed by cleaning with isopropanol or mineral oil. The measured resistance to chemical reagents is based on a 0-3 level scale, where 0 represents no change, 1 represents slight change, 2 represents moderate change, and 3 represents severe change.

[0075] Table 3 Table 4 shows the results of measuring surface properties for an exemplary embodiment of the UV-curable surface coating according to the present invention in Example 1. Specifically, Table 4 discloses the results of the standard test method for chemical resistance of resilient flooring provided by ASTM F925-13. The chemical stainant was placed on the surface of the test sample of Example 1 for 60 minutes, and then cleaned with isopropanol or mineral oil. The measured resistance to the chemical stainant is based on a 0-3 level scale, where 0 represents no change, 1 represents slight change, 2 represents moderate change, and 3 represents severe change.

[0076] Table 4 Table 5 shows the results of measuring surface properties of an exemplary embodiment of the UV-curable surface coating according to the invention in Example 1. Specifically, Table 4 discloses the results of observation and measurement of the scratch resistance of the UV-curable surface coating according to the invention in Example 1. The steps used to determine the scratch resistance of the coating were based on a Mini-Martindale Abrasion and Pilling Tester Model 401. In this method, a weight of 260 grams is added to the top of a 3.5-inch abrasion top plate (125 grams) with a 3.5-inch 3M Scotch-Brite abrasion pad 07447. The test sample is located in the center of the abrasion stage, so the abrasion pad moves longitudinally along the coated sample. The apparatus is run for 25 cycles, visually inspected 10 times, and 1) the amount of coating powder whiting rubbed off and 2) the scratches are evaluated. The process is then repeated after an additional 260 grams of weight is placed on the top plate. The measured scratch resistance is based on a rating scale of 0-3, where 0 indicates no change, 1 indicates slight change, 2 indicates moderate change, and 3 indicates severe change.

[0077] Table 5 The abrasion resistance of the UV-curable surface coating (Example 1) according to the present invention was observed and measured. Specifically, tests were conducted to measure the abrasion resistance of the UV-curable surface coating through to the decorative layer. The test protocol used a Teledyne Taber grinder with a 500g weight and an S-32 wheel. A 4-inch × 4-inch sample was mounted on a plate, and a 1 / 2-inch wide strip of S-42 sandpaper was placed on the grinding wheel. The results were observed after every 50 revolutions. The sandpaper was also replaced after every 50 revolutions. The initial point (IP) is the point at which the decorative layer is worn through. For light commercial applications, the initial wear point is defined as >2000 cycles and >4000 cycles for commercial applications. The initial point (IP) of the UV-curable surface coating was observed at 4400 cycles.

[0078] The efficacy of the antimicrobial additive used in the UV-curable surface coating (Example 1) according to the present invention was measured. Specifically, the efficacy of the antimicrobial additive was observed and measured after 4000 cycles of wiping the surface of the UV-curable surface coating. ISO 22196 is an antimicrobial surface test for measuring antimicrobial activity on plastics and other non-porous surfaces. The test sample was rubbed 4000 times using a Gardner abrasion tester according to ISO 22196. The UV-curable surface coating was continuously moistened with a disinfectant cleaner, and a 3M white pad was used as the wiping pad to simulate 10 years of routine cleaning and maintenance using a low-speed scrubber and a 3M white pad. The bacteria specified for testing were Staphylococcus aureus and Escherichia coli.

[0079] Table 6 shows the results of measuring surface properties of an exemplary embodiment of the UV-curable surface coating according to the invention in Example 1, based on the ISO 22196 test detailed above. Antimicrobial activity was measured as the logarithmic difference between the viable cell counts found on the antimicrobially treated product and the untreated product after bacterial inoculation and culture. The antimicrobial efficacy of the additive is the ability of the antimicrobial agent to inhibit bacterial growth on a material surface treated with the antimicrobial agent, as determined by the antimicrobial activity value. The percentage of antimicrobial efficacy (%) was measured as 1 - 1 / (10^antimicrobial activity value).

[0080] Table 6 The UV-curable surface coating according to the invention in Example 1 was subjected to DIN 51130 (also known as the German slope test) to determine the anti-slip level of the flooring, which would be used in workplaces and work areas with a risk of slipping. This test yields "R" values ​​in the range of R9-R13. R13 is best if the floor may become damp. Only R12 or R13 should be considered for use around swimming pools or changing areas. R11 can be suitable for transitional areas of the floor that occasionally become damp despite efforts to keep them dry, such as the entrance to a shopping mall or a dry changing room floor. R10 can be suitable for floor areas that can generally be kept dry, while the lowest value, R9, should only be considered for floors that never become damp or are rarely used. This test yields an R10 classification for the UV-curable surface coating according to the invention, indicating that the UV-curable surface coating according to the invention meets the standard for high friction and low slip probability.

[0081] The British Pendulum Skid Tester was also used according to the standard test method provided by ASTM E303 for measuring surface friction properties. This device measures the frictional resistance between a rubber slider mounted on the end of a pendulum arm and the surface of the test product. The following pendulum friction values ​​were observed: (1) Dry conditions: 49, Wet conditions: 37. This test also shows that the UV-curable surface coating according to the invention meets the standard and has high friction and low slippage potential.

[0082] The foregoing has described some possible implementations of the invention. Many other embodiments and applications of the LVT of the invention are possible and within the scope and spirit of the invention. Therefore, the foregoing description is intended to be illustrative rather than restrictive, and the scope of the invention is given by the full scope of the appended claims and their equivalents.

Claims

1. A surface covering, the surface covering comprising: Laminated panel, the laminated panel having: Transparent protective layer; A decorative layer with a printed film; Intermediate layer; intermediate base layer; and Bottom base layer; and An ultraviolet (UV) curable surface coating is applied to the laminated panel, the ultraviolet (UV) curable surface coating having: First coating; and A second coating having a composition different from that of the first coating, wherein the first coating is cured at a lower energy compared to the second coating, and the second coating is cured at a higher energy to cure both the first coating and the second coating; The UV-curable surface coating has the following composition: Oligomers; monomer; Photosensitizer; Abrasive wear-resistant particles, wherein the abrasive wear-resistant particles include silicon carbide (SiC) particles, wherein at least 50% of the silicon carbide (SiC) particles have a particle size of less than 45 μm; An antimicrobial additive, wherein the antimicrobial additive is selected from the group consisting of: N-butyl-1,2-benzisothiazolin-3-one, alkyl dimethyl saccharin ammonium, 2-pyridinium mercaptan-1-zinc oxide, 10,10'-oxobisphenoxarsenic (OBPA), 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOIT), and any mixture thereof.

2. The surface covering according to claim 1, wherein the oligomer is an acrylate resin.

3. The surface covering according to claim 2, wherein the oligomer comprises a urethane acrylate oligomer.

4. The surface covering according to claim 3, wherein the monomer comprises a monofunctional monomer, a difunctional monomer, or a polyfunctional monomer.

5. The surface covering according to claim 4, wherein the monofunctional monomer is selected from the group consisting of: acrylic acid, N-vinyl-2-pyrrolidone, isobornyl acrylate and esters of acrylic acid, and methacrylic acid derivatives.

6. The surface covering according to claim 4, wherein the multifunctional monomer is a trifunctional monomer selected from the group consisting of trimethylolpropane triacrylate (TMPTA) or pentaerythritol triacrylate (PETA).

7. The surface covering according to claim 4, wherein the bifunctional monomer is selected from the group consisting of: tripropylene glycol diacrylate (TPGDA), 1,6-hexanediol diacrylate (HDDA), Dianol diacrylate (DDA), neopentyl glycol diacrylate (NPGDA), hexamethylene diacrylate, and 1,4-butylene glycol diacrylate (BDDA).

8. The surface coating according to claim 7, wherein the photoinitiator is selected from the group consisting of: benzophenone, benzophenone derivatives, benzoin, benzoin derivatives, acetophenone, acetophenone derivatives, aromatic ketone amine systems, such as hydroxycyclohexylphenyl ketone.

9. The surface coating according to claim 1, wherein 90% of the silicon carbide (SiC) particles have a particle size of less than 45 μm.

10. The surface coating of claim 9, wherein the ultraviolet (UV) curable surface coating composition comprises about 5 to about 15 wt% silicon carbide (SiC) particles.

11. The surface covering according to claim 2, wherein the antimicrobial additive is N-butyl-1,2-benzisothiazolin-3-one.

12. The surface covering of claim 11, wherein the UV-curable surface coating composition comprises about 0.05 to about 1.0 wt% of the antimicrobial additive.

13. The surface covering of claim 12, wherein the UV-curable surface coating composition comprises about 0.1 to about 0.5 wt% of the antimicrobial additive.

14. The surface covering of claim 13, wherein the ultraviolet (UV) curable surface coating composition comprises a first coating having about 40 to about 60 wt% of a first oligomer.

15. The surface coating of claim 14, wherein the ultraviolet (UV) curable surface coating composition comprises a second coating having about 50 to about 70 wt% of a second oligomer.

16. The surface covering of claim 15, wherein the ultraviolet (UV) curable surface coating composition comprises about 15 to about 55% by weight (wt%) of one or more monomers.

17. The surface coating of claim 16, wherein the first coating comprises about 25 to about 35 wt% of a first monomer and about 1 to about 5 wt% of a second monomer.

18. The surface coating of claim 17, wherein the second coating comprises about 15 to about 25 wt% of a first monomer, about 5 to about 15 wt% of a second monomer and about 1 to about 5 wt% of a third monomer.

19. The surface coating of claim 18, wherein the ultraviolet (UV) curable surface coating composition comprises about 1 to about 20 wt% of one or more photoinitiators.

20. The surface coating of claim 1, wherein the ultraviolet (UV) curable surface coating further comprises a silica matting agent.

21. The surface coating according to claim 1, wherein the photoinitiator is hydroxycyclohexylphenyl ketone.

22. The surface covering of claim 1, wherein the laminated panel further comprises a glass fiber sparse cloth.

23. A surface covering, the surface covering comprising: Laminated panel, the laminated panel having: Transparent wear-resistant layer; grassroots level; A decorative layer having a printed film, the decorative layer being located between the transparent wear-resistant layer and the base layer; A UV-curable surface coating, wherein the UV-curable surface coating has: First coating; and A second coating has a different composition from the first coating. The first coating cures at a lower energy level compared to the second coating, while the second coating cures at a higher energy level, thus curing both the first and second coatings. The UV-curable surface coating is located on the transparent wear-resistant layer, and the UV-curable surface coating has the following composition: Abrasive wear-resistant particles, wherein the abrasive wear-resistant particles comprise silicon carbide (SiC) particles, wherein 50% of the silicon carbide (SiC) particles have a particle size of less than 45 μm; and An antimicrobial additive, wherein the antimicrobial additive is selected from the group consisting of: N-butyl-1,2-benzisothiazolin-3-one, alkyl dimethyl saccharin ammonium, 2-pyridinium thiol-1-zinc oxide, 10,10'-oxobisphenoxarsenic (OBPA), 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOIT), and any mixture thereof.

24. A surface covering, the surface covering comprising: Laminated panels; A UV-curable multi-part surface coating, said UV-curable multi-part surface coating being applied to the laminated panel, and having: A first coating, the first coating having a first composition; and A second coating having a second composition different from the first composition of the first coating, wherein the first coating is cured in stages, and in the staged curing process, the first coating is semi-cured at a first lower energy level before the second coating is applied. The second coating is applied onto the semi-cured first coating; The UV-curable surface multipart coating is ultimately cured at a second higher energy, which is sufficient to completely cure both the first coating and the second coating.

25. A surface covering, the surface covering comprising: Laminated panels; and A UV-curable surface coating, said UV-curable surface coating being applied to the laminated panel, and having: First coating; and A second coating having a different composition from the first coating, wherein the first coating is cured at a lower energy level compared to the second coating, and the second coating is cured at a higher energy level to cure both the first coating and the second coating; Abrasive wear-resistant particles, wherein the abrasive wear-resistant particles comprise silicon carbide (SiC) particles, wherein at least 50% of the silicon carbide (SiC) particles have a particle size of less than 45 μm; and An antimicrobial additive, wherein the antimicrobial additive is selected from the group consisting of: N-butyl-1,2-benzisothiazolin-3-one, alkyl dimethyl saccharin ammonium, 2-pyridinium thiol-1-zinc oxide, 10,10'-oxobisphenoxarsenic (OBPA), 4,5-dichloro-2-octyl-4-isothiazolin-3-one (DCOIT), and any mixture thereof.

26. A surface covering, the surface covering comprising: Laminated panel, the laminated panel having a top surface, the laminated panel having: Transparent protective layer; A decorative layer with a printed film; Intermediate layer; intermediate base layer; and Bottom base layer; The thickness of the laminated panel is 4mm to 6mm; as well as A UV-curable surface coating is applied to the top surface of the laminated panel, the UV-curable surface coating having: A first coating comprising about 40 to about 60 wt% of a first oligomer, about 25 to about 35 wt% of a first monomer, and about 1 to about 5 wt% of a second monomer; and The second coating has about 50 to about 70 wt% of a second oligomer, about 15 to about 25 wt% of a first monomer, about 5 to about 15 wt% of a second monomer and about 1 to about 5 wt% of a third monomer, wherein the first coating is cured at a lower energy than the second coating and the second coating is cured at a higher energy to cure both the first coating and the second coating. The UV-curable surface coating also includes: Oligomers, wherein the oligomers are acrylate resins; Photosensitizer; Abrasive wear-resistant particles, wherein the abrasive wear-resistant particles comprise silicon carbide (SiC) particles, wherein at least 50% of the silicon carbide (SiC) particles have a particle size of less than 45 μm; and An antimicrobial additive, wherein the antimicrobial additive is N-butyl-1,2-benzisothiazolin-3-one; The first monomer, the second monomer, and the third monomer include monofunctional monomers selected from the group consisting of: acrylic acid, N-vinyl-2-pyrrolidone, isobornyl acrylate and esters of acrylic acid, and methacrylic acid derivatives. The photoinitiator is selected from the group consisting of: benzophenone, benzophenone derivatives, benzoin, benzoin derivatives, acetophenone, acetophenone derivatives, and aromatic ketone-amine systems, such as hydroxycyclohexylphenyl ketone; and 90% of the silicon carbide (SiC) particles have a particle size of less than 45 μm.

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