Water-based UV-curable coating composition

Abstract

A water-based UV-curable coating composition is disclosed, comprising a polyurethane resin and a PDMS-(meth)acrylate oligomer. Also disclosed is a use of the water-based UV-curable coating composition for coating a substrate, and a substrate at least partially coated with the water-based UV-curable coating composition.

Description

[Technical Field]

[0001] The present invention relates to the field of coatings, specifically to water-based UV-curable coatings. [Background technology]

[0002] In 3C coatings, including those for computers, communications equipment, and consumer electronics, waterborne UV-curable coatings for plastics such as polycarbonate (PC), polycarbonate + acrylonitrile / butadiene / styrene copolymer (PC + ABS), polycarbonate + carbon fiber (PC + CF), and polycarbonate + glass fiber (PC + GF) generally have relatively poor stain resistance. To improve stain resistance, those skilled in the art have conducted extensive research. Currently, a widely used method is to prepare a polydimethylsiloxane (PDMS)-modified polyurethane resin and then formulate a waterborne UV coating based on the modified polyurethane resin.

[0003] However, preparing a PDMS-modified polyurethane resin suited to an application scenario requires a lot of research effort and cost, and it is also difficult in the art to design and balance a formulation based on the prepared PDMS-modified polyurethane resin so that the coating has stain resistance without degrading other performances. Summary of the Invention [Problem to be solved by the invention]

[0004] Therefore, there is an urgent practical need and potential commercial value to obtain waterborne UV curable coatings that have both stain resistance and other mechanical and aesthetic properties in a simple and convenient manner. [Means for solving the problem]

[0005] The present inventors have conducted numerous studies and developed a water-based UV-curable coating composition that has the advantages of simple preparation and stain resistance, while at the same time meeting the various mechanical property and appearance requirements of 3C coatings.

[0006] The present invention provides a water-based UV-curable coating composition comprising a polyurethane resin and a PDMS-(meth)acrylate oligomer.

[0007] The present invention further provides a coated substrate comprising a substrate and an aqueous UV-curable coating composition deposited on at least a portion of the substrate, the aqueous UV-curable coating composition comprising a polyurethane resin and a PDMS-(meth)acrylate oligomer.

[0008] The present invention further provides a use of the aqueous UV-curable coating composition for coating a substrate, wherein the aqueous UV-curable coating composition comprises a polyurethane resin and a PDMS-(meth)acrylate oligomer.

[0009] The features and advantages of the present invention are particularly presented in the following detailed description of the embodiments. [Brief explanation of the drawings]

[0010] [Figure 1] 1 shows the results of a water-based UV curable coating according to the present invention and a comparative coating in a stain resistance test. DETAILED DESCRIPTION OF THE INVENTION

[0011] As used herein, unless expressly stated otherwise, numbers used in the specification and claims, e.g., numbers expressing values, ranges, contents, or percentages, are understood to be modified in all respects by the term "about," even if the term is not expressly designated. Accordingly, unless indicated to the contrary, all numerical parameters set forth in the description and claims herein are approximations and may vary depending upon the properties obtained by the present invention.

[0012] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values ​​set forth in the specific examples are reported as precisely as possible. However, any numerical value inherently contains certain errors that are necessarily the result of the standard deviation found in its corresponding measuring method.

[0013] Additionally, it should be understood that any numerical range recited herein is intended to encompass all subranges subsumed therein. For example, a range of "1 to 10" is intended to include all subranges between (and including) the minimum value of 1 and the recited maximum value of 10, i.e., having a minimum value of 1 or greater and a maximum value of 10 or less.

[0014] In this application, the use of the singular includes the plural and the use of the plural includes the singular, unless expressly stated otherwise. Further, in this application, the use of "or" means "and / or" unless expressly stated otherwise, although in some cases "and / or" may be explicitly used. Additionally, in this application, the use of "a" or "an" means "at least a / an" unless expressly stated otherwise. For example, "a" polymer, "a" coating, etc., refers to one or more of any of those items. Also, as one skilled in the art will recognize, feature(s) of one embodiment can be used with other embodiments, even if not explicitly stated.

[0015] In this application, the term "comprising" and similar terms means including, but not limited to, without excluding any modifications or additions. Furthermore, although the present invention describes coating compositions and / or methods with "comprising" or similar terms, those coating compositions etc. may also be described as "consisting essentially of" or "consisting of."

[0016] As used herein, the term "aqueous" means that the solvent in the coating composition comprises at least 50% water by weight. The coating composition according to the present invention is a low-VOC coating composition. As used herein, the term "VOC (volatile organic compound)(ies)" refers to any organic compound having a boiling point of 250°C (482°F) or less, measured at standard atmospheric pressure of 101.3 kPa. Organic solvents are often the primary source of VOCs. The coating composition according to the present invention has a VOC content of less than 200 g / L, which meets the national standard that aqueous coatings should have a VOC of less than 420 g / L. The VOC value can be determined by measuring the content of various organic compound components in the coating by gas chromatography and then adding the contents of the various components.

[0017] As used herein, "UV curable" means that the material in the coating composition cures to form a film after exposure to ultraviolet (UV) light. As used herein, the term "cured / curing / curable" refers to the process by which the material "sets" to form an irreversible crosslinked network that no longer flows, melts, or dissolves. As used herein, the term "cured / curing" can be used interchangeably with "crosslinked / crosslinking."

[0018] The aqueous UV-curable coating composition according to the present invention can be used as a "topcoat." "Topcoat" refers to the outermost coating in a multi-layer coating system. When the aqueous UV-curable coating composition according to the present invention is used as a topcoat, it can be used in combination with any primer / basecoat as long as they are compatible with each other. Alternatively, the aqueous UV-curable coating composition according to the present invention can be applied directly to the surface of a substrate without the prior application of any primer / basecoat.

[0019] The present invention provides a water-based UV-curable coating composition comprising a polyurethane resin and a PDMS-(meth)acrylate oligomer.

[0020] The polyurethane resin used in the aqueous UV-curable coating composition according to the present invention refers to a polymer having repeating units containing carbamate functional groups. The polyurethane can include carbamate-linked organic units selected from the group consisting of simple diols, polyester diols, polyether diols, and / or polycarbonate diols.

[0021] Preferably, the polyurethane resin can comprise a (meth)acrylate-functionalized polyurethane resin. A (meth)acrylate-functionalized polyurethane resin refers to a polyurethane resin containing (meth)acrylate-based functional groups attached thereto. Preferably, the polyurethane resin can comprise 30% to 100% by weight of the (meth)acrylate-functionalized polyurethane resin, for example, at least 40% by weight, e.g., at least 50% by weight, and / or up to 90% by weight, e.g., up to 80% by weight, based on the total weight of the resin. Preferably, the polyurethane resin can comprise a (meth)acrylate-functionalized polyurethane resin and a different polyurethane resin, where the different polyurethane resin does not contain (meth)acrylate-based functional groups.

[0022] The polyurethane resin suitable for the present invention has a glass transition temperature (T g ), for example, T from 0℃ to 100℃ g For example, T of 20℃ to 80℃ g T g can be determined by dynamic mechanical analysis (DMA) using a TA Instruments Q800 instrument with the following parameters: frequency of 10 Hz, amplitude of 5 mm, and temperature range of -100°C to 250°C. g is determined as the peak of the tan δ curve according to ASTM D7028.

[0023] Preferably, the polyurethane resin for this application is in the form of an aqueous dispersion having a solids content of about 30% to 60% by weight, the term "solids content" referring to the mass remaining after evaporation of the solvent relative to the mass of the original dispersion.

[0024] Based on the total weight of the aqueous UV-curable coating composition, the polyurethane resin can be present in the composition in an amount of about 10 wt.% or more, e.g., about 20 wt.% or more, e.g., about 25 wt.% or more, and / or about 70 wt.% or less, e.g., about 50 wt.% or less, e.g., about 45 wt.% or less. Based on the total weight of the aqueous UV-curable coating composition, the polyurethane resin can be present in a range of about 10 wt.% to 70 wt.%, e.g., about 20 wt.% to 50 wt.%, e.g., about 25 wt.% to 45 wt.%, or any other combination of these endpoints.

[0025] The PDMS-(meth)acrylate oligomer used in the aqueous UV-curable coating composition according to the present invention refers to an oligomer containing a PDMS moiety and a (meth)acrylate moiety. The PDMS moiety comprises polydimethylsiloxane. The (meth)acrylate moiety can contain one or more (meth)acrylate units.

[0026] Preferably, the PDMS-(meth)acrylate oligomer is water-dispersible. "Water-dispersible" means that the oligomer contains hydrophilic groups and can be uniformly dispersed in water or an aqueous solvent without phase separation or similar phenomena. Preferably, the PDMS-(meth)acrylate oligomer contains polyoxyethylene and / or polyoxypropylene block moieties. Preferably, the PDMS-(meth)acrylate oligomer contains a (PDMS-polyoxyethylene and / or polyoxypropylene-(meth)acrylate) structure. Preferably, the PDMS-(meth)acrylate oligomer contains a linear and / or branched structure. As used herein, the term "linear" means that the oligomeric chain is substantially linear. As used herein, the term "branched" means that the oligomeric chain contains side chain(s) attached to the backbone or otherwise covalently attached side chain(s).

[0027] The PDMS-(meth)acrylate oligomers suitable for the present invention have a number average molecular weight (M n ) is ≦10,000, e.g., M n is ≦8,000, e.g., M n is ≦6,000. M n can be determined by gel permeation chromatography using suitable standards, for example polystyrene standards.

[0028] Based on the total weight of the aqueous UV-curable coating composition, the PDMS-(meth)acrylate oligomer can be present in the composition in an amount of about 0.1 wt.% or more, e.g., about 0.5 wt.% or more, e.g., about 1 wt.% or more, and / or about 10 wt.% or less, e.g., about 8 wt.% or less, e.g., about 6 wt.% or less. Based on the total weight of the aqueous UV-curable coating composition, the PDMS-(meth)acrylate oligomer can be present in the composition in an amount of about 0.1 wt.% to 10 wt.%, e.g., about 0.5 wt.% to 8 wt.%, e.g., about 1 wt.% to 6 wt.%, or any other combination of ranges using these endpoints.

[0029] In the aqueous UV-curable coating composition of the present invention, the polyurethane resin and the PDMS-(meth)acrylate oligomer can constitute at least 60 wt%, preferably at least 80 wt%, for example at least 95 wt%, or even 100 wt% of the total solids weight of the composition. In the aqueous UV-curable coating composition of the present invention, the polyurethane resin can constitute at least 30 wt%, for example at least 40 wt%, for example at least 50 wt%, preferably at least 60 wt%, for example at least 70 wt%, for example at least 80 wt%, for example at least 90 wt%, at least 95 wt%, or at least 98 wt% of the total solids weight of the composition. Here, "total solids weight" refers to the total weight of the coating composition after solvent removal.

[0030] Suitably, in the aqueous UV-curable coating composition of the present invention, the weight ratio of polyurethane resin to PDMS-(meth)acrylate oligomer may be about 40:1 to 300:1, such as about 50:1 to 250:1, for example, about 80:1 to 150:1.

[0031] The aqueous UV-curable coating composition according to the present invention may further comprise a polyisocyanate. The polyisocyanate may consist of the following monomers: hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and / or dicyclohexylmethane-4,4'-diisocyanate (HMDI). Preferably, the polyisocyanate may comprise the following polymers (at least trimers): hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and / or dicyclohexylmethane-4,4'-diisocyanate (HMDI). For example, the polyisocyanate may comprise an HDI trimer and / or an IPDI trimer.

[0032] Based on the total weight of the aqueous UV-curable coating composition, the polyisocyanate can be present in the composition in an amount of about 1% to 10% by weight, for example, about 2% to 6% by weight.

[0033] The aqueous UV-curable coating composition according to the present invention can further comprise a surfactant. Preferably, the surfactant used in the present invention comprises a nonionic surfactant having wetting and defoaming properties. Generally, the matting agent can be present in the composition in an amount of about 0% to 2% by weight, based on the total weight of the aqueous UV-curable coating composition.

[0034] The aqueous UV-curable coating composition according to the present invention can further comprise a matting agent. The matting agent includes an inorganic matting agent and / or an organic matting agent. Preferably, the inorganic matting agent includes a silica-based matting agent. The silica-based matting agent can include silica with or without surface treatment. The organic matting agent includes a polymethylurea (PUM)-based matting agent. Generally, the matting agent can be present in the composition in an amount of about 0% to 5% by weight, for example, about 1% to 4% by weight, based on the total weight of the aqueous UV-curable coating composition.

[0035] The aqueous UV-curable coating composition according to the present invention can further comprise a photoinitiator. The photoinitiator can decompose under UV irradiation, resulting in polymerization of the polymerizable oligomers and / or monomers to form a three-dimensional network structure. Generally, the photoinitiator can be present in the composition in an amount of about 1% to 5% by weight, based on the total weight of the aqueous UV-curable coating composition.

[0036] The aqueous UV-curable coating composition according to the present invention can further comprise a substrate wetting agent. The wetting agent can improve the surface tension and permeability of the coating composition, better wet the coating layer, and improve the adhesion of the coating. Preferably, the wetting agent comprises an organosilicon and / or poly(meth)acrylate wetting agent. Generally, the substrate wetting agent can be present in the composition in an amount of about 0% to 2% by weight, based on the total weight of the aqueous UV-curable coating composition.

[0037] The aqueous UV-curable coating composition according to the present invention can further comprise a thickener. The thickener can improve the viscosity of the coating, improve the wet film thickness, and prevent the coating from settling and phase separation. Preferably, the thickener includes an alkali-soluble anionic thickener and an associative thickener. Generally, the thickener can be present in the composition in an amount of about 0% to 5% by weight, based on the total weight of the aqueous UV-curable coating composition.

[0038] The aqueous UV-curable coating composition according to the present invention can further contain an organic solvent. The organic solvent can reduce the surface tension of the composition and increase the evaporation rate. Preferably, the organic solvent comprises an alcohol such as butanol, isopropanol, or 2-butoxyethanol. Generally, the organic solvent can be present in the composition in an amount of about 0% to 5% by weight, based on the total weight of the aqueous UV-curable coating composition.

[0039] The aqueous UV-curable coating composition according to the present invention may further comprise 40 to 70% by weight of water.

[0040] The aqueous UV-curable coating composition according to the present invention can further comprise a (meth)acrylate resin and / or a polyester resin, or other film-forming material. The aqueous UV-curable coating composition according to the present invention can further comprise one or more additional auxiliary components (additives), including, but not limited to, the following: a rheology aid to improve flow and leveling properties and reduce defects; a preservative to protect the coating from mildew; a pH adjuster to control pH and stabilize the coating; a wax to increase scratch resistance and improve hand feel; a pigment to impart color, fill, and / or abrasion resistance to the coating; and the like. When present, each type of auxiliary component is present in an amount of at most about 5 wt %, based on the total weight of the aqueous UV-curable coating composition.

[0041] The aqueous UV-curable coating composition according to the present invention can be prepared by uniformly mixing a composition containing a polyurethane resin and a PDMS-(meth)acrylate oligomer at room temperature. As used herein, "room temperature" refers to a temperature of 20°C to 30°C, for example, 22°C.

[0042] The present invention further provides a use of an aqueous UV-curable coating composition for coating a substrate, the aqueous UV-curable coating composition comprising a polyurethane resin and a PDMS-(meth)acrylate oligomer. As used herein, the term "substrate" refers to a material with a rough or smooth surface, whether coated or not. The substrate includes a plastic substrate. Suitable substrates include, but are not limited to, polycarbonate, polycarbonate + acrylonitrile / butadiene / styrene copolymer, polycarbonate + carbon fiber, and / or polycarbonate + glass fiber. The substrate may be a substrate for use in a vehicle display screen, a mobile phone PET protective film, a computer display screen, a keyboard, and / or a laptop housing.

[0043] The present invention further provides a substrate coated with an aqueous UV-curable coating composition, comprising a substrate and an aqueous UV-curable coating composition deposited on at least a portion of the substrate, wherein the aqueous UV-curable coating composition comprises a polyurethane resin and a PDMS-(meth)acrylate oligomer.

[0044] The coating composition of the present invention can be coated by any standard method known in the art, such as spraying, dipping, roller coating, brush coating, etc., and then cured under UV radiation to form a coating film. For example, the coating composition can be baked at 50°C to 70°C for about 10 to 15 minutes to evaporate the solvent and water, followed by curing under UV radiation at 800 to 1,200 mJ / cm. 2 UV energy of 100-200mW / m2 The coating can be carried out by applying UV radiation having an optical radiation intensity of 15 to 20 μm. The coating generally has a film thickness in the range of 15 to 20 μm. [Example]

[0045] The following examples are provided to further illustrate the invention but should not be construed as limiting the invention to the details thereof. All parts and percentages in the following examples are by weight unless otherwise indicated.

[0046] Examples 1 to 4: Water-based UV-curable coating compositions Ex-1, Ex-2, Ex-3, and Ex-4 according to the present invention were prepared according to the ingredients and amounts listed in Table 1. Specifically, the ingredients listed in the table were placed in a container under stirring and mixed for about 30 minutes, and then the resulting mixture was sieved through a 200-mesh sieve. [Table 1]

[0047] Comparative Examples 1 to 4: Comparative aqueous UV-curable coating compositions CE-1, CE-2, CE-3, and CE-4 were prepared according to the ingredients and amounts listed in Table 2. Specifically, the ingredients listed in the table were placed in a container under stirring and mixed for about 30 minutes, and then the resulting mixture was sieved through a 200-mesh sieve. [Table 2]

[0048] Performance test: First, the aqueous UV-curable coating compositions Ex-1, Ex-2, Ex-3, and Ex-4 according to the present invention and the aqueous UV-curable coating compositions CE-1, CE-2, CE-3, and CE-4 according to the comparative examples were applied to a polycarbonate substrate, baked at about 60°C for about 10 minutes, and then irradiated with 1,000 mJ / cm 2of UV energy and 120mW / cm 2 The specimen was exposed to UV radiation having an optical radiation intensity of 10 ...

[0049] The coated substrates were subjected to various performance tests as follows:

[0050] 1-VOC Herein, the VOC content (water-free, g / L) of the water-based UV-curable coating compositions according to the present invention, Ex-1, Ex-2, Ex-3 and Ex-4, was calculated in the following manner.

[0051] For 1 g of composition, the mass m of each component in the composition i , the mass of water in the composition m w , and the density ρ of the composition s were measured respectively.

[0052] It was calculated according to the following formula:

number

[0053] 2-Gloss The gloss of the resulting coating was measured at 60° using a commercial gloss meter BYK Micro-Gloss. [Table 4]

[0054] 3-Water contact angle The water contact angles of the coatings were measured using a commercially available optical contact angle meter. [Table 5]

[0055] 4-Stain resistance In the present invention, the stain resistance of the coating was evaluated by writing a mark on the coating with a red Sharpie oil pen, then drying it at room temperature for 15 minutes, wiping the mark five times with a dry paper towel, and evaluating the stain resistance of the coating based on the state of the mark after wiping. Specifically, the stain resistance was rated (scored) from 0 to 10, with 0 representing the worst, i.e., no change in the red mark, and 10 representing the best, i.e., no red mark remained. [Table 6]

[0056] The stain resistance test results of the waterborne UV-curable coating compositions according to the present invention, Ex-1, Ex-2, Ex-3, and Ex-4, and the comparative waterborne UV-curable coating compositions, CE-1, CE-2, CE-3, and CE-4, are also shown in FIG. 1 .

[0057] It can be seen that the water-based UV-curable coating composition provided by the present invention has excellent stain resistance, and at the same time, the water-based UV-curable coating composition according to the present invention can meet other requirements in terms of appearance and mechanical properties.

[0058] While particular embodiments of the present invention have been illustrated and described, it would be obvious to those skilled in the art that many other changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, it is intended that the appended claims cover all such changes and modifications that are within the scope of this invention. Various aspects or embodiments that can be included in the present invention are summarized as follows. [1]. A water-based UV-curable coating composition comprising a polyurethane resin and a PDMS-(meth)acrylate oligomer. [2]. 2. The coating composition according to item 1, wherein the PDMS-(meth)acrylate oligomer is water-dispersible. [3]. 3. The coating composition according to item 1 or 2, wherein the PDMS-(meth)acrylate oligomer comprises a polyoxyethylene and / or polyoxypropylene block moiety. [4]. 4. The coating composition according to any one of items 1 to 3, wherein the PDMS-(meth)acrylate oligomer comprises a structure of (PDMS-polyoxyethylene and / or polyoxypropylene-(meth)acrylate). [5]. 5. The coating composition according to any one of the above items 1 to 4, wherein the PDMS-(meth)acrylate oligomer comprises a linear or branched structure. [6]. 6. The coating composition according to any one of the above items 1 to 5, wherein the PDMS-(meth)acrylate oligomer has a number average molecular weight of ≦10,000. [7]. 7. The coating composition according to any one of items 1 to 6, wherein the composition comprises less than 10 wt % of the PDMS-(meth)acrylate oligomer, based on the total weight of the composition. [8]. 8. The coating composition according to any one of the above items 1 to 7, wherein the polyurethane resin comprises a (meth)acrylate-functionalized polyurethane resin. [9]. 9. The coating composition according to any one of the above items 1 to 8, wherein the polyurethane resin comprises 30 to 100 wt % of a (meth)acrylate-functionalized polyurethane resin, based on the total weight of the polyurethane resin.

[10] . 10. The coating composition according to any one of items 1 to 9, wherein the polyurethane resin has a glass transition temperature of -30°C to 110°C.

[11] . 11. The coating composition according to any one of the above items 1 to 10, wherein the polyurethane resin constitutes at least 30% by weight of the total solid weight of the composition.

[12] . 12. The coating composition according to any one of the above items 1 to 11, wherein the polyurethane resin and the PDMS-(meth)acrylate oligomer constitute at least 80 wt % of the total solid weight of the composition.

[13] . 13. The coating composition according to any one of the above items 1 to 12, wherein the weight ratio of the polyurethane resin to the PDMS-(meth)acrylate oligomer is comprised between 40:1 and 300:1.

[14] . 14. The coating composition according to any one of the above items 1 to 13, having a VOC content of less than 200 g / L when measured without water.

[15] . 1. A coated substrate comprising: a substrate; and an aqueous UV-curable coating composition deposited on at least a portion of the substrate, wherein the aqueous UV-curable coating composition comprises a polyurethane resin and a PDMS-(meth)acrylate oligomer.

[16] . 16. The coated substrate according to item 15, wherein the substrate comprises polycarbonate, polycarbonate + acrylonitrile / butadiene / styrene copolymer, polycarbonate + carbon fiber, and / or polycarbonate + glass fiber.

[17] . 17. The coated substrate according to item 15 or 16, wherein the substrate is for use in a vehicle display screen, a mobile phone PET protective film, a computer display screen, a keyboard, and / or a laptop housing.

[18] . 1. Use of an aqueous UV-curable coating composition for coating a substrate, wherein the aqueous UV-curable coating composition comprises a polyurethane resin and a PDMS-(meth)acrylate oligomer.

[19] . 19. The use according to item 18, wherein the substrate comprises polycarbonate, polycarbonate + acrylonitrile / butadiene / styrene copolymer, polycarbonate + carbon fiber, and / or polycarbonate + glass fiber.

[20] . 20. The use according to item 18 or 19, wherein the substrate is a substrate for use in a vehicle display screen, a mobile phone PET protective film, a computer display screen, a keyboard, and / or a laptop housing.

Claims

1. 1. A water-based UV-curable coating composition comprising a polyurethane resin and a PDMS-(meth)acrylate oligomer, the PDMS-(meth)acrylate oligomer is water-dispersible; the PDMS-(meth)acrylate oligomer contains hydrophilic groups so that the oligomer can be uniformly dispersed in water; the PDMS-(meth)acrylate oligomer contains a polyoxyethylene and / or polyoxypropylene block moiety; the PDMS-(meth)acrylate oligomer comprises a structure of (PDMS-polyoxyethylene and / or polyoxypropylene-(meth)acrylate); the PDMS-(meth)acrylate oligomer has a number average molecular weight of ≦10,000; the composition comprises less than 10 wt. % of the PDMS-(meth)acrylate oligomer, based on the total weight of the composition; Aqueous UV curable coating compositions.

2. The coating composition of claim 1 , wherein the PDMS-(meth)acrylate oligomer comprises a linear or branched structure.

3. The coating composition of claim 1 or 2, wherein the polyurethane resin comprises a (meth)acrylate-functionalized polyurethane resin.

4. 3. The coating composition of claim 1, wherein the polyurethane resin comprises 30 to 100 wt. % of the (meth)acrylate-functionalized polyurethane resin, based on the total weight of the polyurethane resin.

5. 3. The coating composition according to claim 1, wherein the polyurethane resin has a glass transition temperature of from -30°C to 110°C.

6. 3. The coating composition of claim 1, wherein the polyurethane resin comprises at least 30% by weight of the total solids weight of the composition.

7. 3. The coating composition of claim 1, wherein the polyurethane resin and the PDMS-(meth)acrylate oligomer constitute at least 80% by weight of the total solids weight of the composition.

8. The coating composition of claim 1 or 2, wherein the weight ratio of the polyurethane resin to the PDMS-(meth)acrylate oligomer is comprised between 40:1 and 300:

1.

9. 3. The coating composition of claim 1 or 2, having a VOC content of less than 200 g / L when measured without water.

10. A coated substrate comprising a substrate and an aqueous UV curable coating composition deposited on at least a portion of the substrate, the aqueous UV-curable coating composition comprises a polyurethane resin and a PDMS-(meth)acrylate oligomer; the PDMS-(meth)acrylate oligomer is water-dispersible; the PDMS-(meth)acrylate oligomer contains hydrophilic groups so that the oligomer can be uniformly dispersed in water; the PDMS-(meth)acrylate oligomer contains a polyoxyethylene and / or polyoxypropylene block moiety; the PDMS-(meth)acrylate oligomer comprises a structure of (PDMS-polyoxyethylene and / or polyoxypropylene-(meth)acrylate); the PDMS-(meth)acrylate oligomer has a number average molecular weight of ≦10,000; the composition comprises less than 10 wt. % of the PDMS-(meth)acrylate oligomer, based on the total weight of the composition; Coated substrate.

11. 11. The coated substrate of claim 10, wherein the substrate comprises polycarbonate, polycarbonate plus acrylonitrile / butadiene / styrene copolymer, polycarbonate plus carbon fiber, and / or polycarbonate plus glass fiber.

12. 12. The coated substrate of claim 10 or 11, wherein the substrate is for use in a vehicle display screen, a mobile phone PET protective film, a computer display screen, a keyboard, and / or a laptop housing.

13. 1. Use of an aqueous UV-curable coating composition for coating a substrate, comprising: the aqueous UV-curable coating composition comprises a polyurethane resin and a PDMS-(meth)acrylate oligomer; the PDMS-(meth)acrylate oligomer is water-dispersible; the PDMS-(meth)acrylate oligomer contains hydrophilic groups so that the oligomer can be uniformly dispersed in water; the PDMS-(meth)acrylate oligomer contains a polyoxyethylene and / or polyoxypropylene block moiety; the PDMS-(meth)acrylate oligomer comprises a structure of (PDMS-polyoxyethylene and / or polyoxypropylene-(meth)acrylate); the PDMS-(meth)acrylate oligomer has a number average molecular weight of ≦10,000; the composition comprises less than 10 wt. % of the PDMS-(meth)acrylate oligomer, based on the total weight of the composition; use.

14. 14. The use according to claim 13, wherein the substrate comprises polycarbonate, polycarbonate plus acrylonitrile / butadiene / styrene copolymer, polycarbonate plus carbon fiber, and / or polycarbonate plus glass fiber.

15. 15. Use according to claim 13 or 14, wherein the substrate is a substrate for use in a vehicle display screen, a mobile phone PET protective film, a computer display screen, a keyboard and / or a laptop housing.

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