Photocurable composition and method for manufacturing decorative sheet using the same

Abstract

The present invention relates to a photocurable composition providing a good appearance without gloss and a manufacturing method of a decorative sheet using the same.

Description

TECHNICAL FIELD

[0001] The present invention relates to a photocurable composition providing a non-glossy excellent appearance and a manufacturing method of a decorative sheet using the same. BACKGROUND

[0002] A decorative sheet is used to express natural texture such as wood, stone, etc. or various patterns on the surface of a base material, and is widely used as a surface material of a building interior decoration material, furniture, home appliance, etc. In the case of a decorative sheet using an existing coating composition, there is a problem of environmental pollution due to the use of an organic solvent. In addition, as a raw material of an existing decorative sheet, polypropylene (PP) or polyvinyl chloride (PVC) is mainly used, but as the demand for eco-friendly raw materials increases, a decorative sheet using a polyethylene terephthalate (PET) raw material is more frequently used in eco-friendly building materials such as kitchen furniture, closet, shoe cabinet, etc. Therefore, there is a demand for development of a photocurable composition that does not use an organic solvent and can be applied to eco-friendly raw materials such as PET.

[0003] In addition, recently, as the aesthetic sense of a building interior decoration material, furniture, home appliance is increasingly valued, development of a non-glossy decorative sheet that can form a high-class appearance is actively being conducted. As one example, Korean Granted Patent 10-2155078 discloses a UV-curable non-glossy coating composition containing a matting agent such as silica, aluminum, etc. However, the matting agent is generally a porous substance, and is located on the surface of a coated layer due to shrinkage of the coating composition upon curing, and thus there is a problem of increasing the surface adsorption of foreign substances and increasing the contamination of a sheet.

[0004] On the other hand, a method of using an excimer lamp to specifically implement a non-glossy effect without using a matting agent is suggested. However, there is a problem of generating a plurality of irregular defects on the surface of a decorative sheet when using an excimer lamp.

[0005] Therefore, there is a demand for a photocurable composition that is eco-friendly and can minimize irregular defects generated on the surface of a sheet while specifically implementing a non-glossy effect without using a matting agent, and a manufacturing method of a decorative sheet using the same. SUMMARY

[0006] PROBLEMS TO BE SOLVED

[0007] The present invention provides a photocurable composition that is eco-friendly and can minimize irregular defects generated on the surface of a sheet while specifically implementing a non-glossy effect without using a matting agent, and a manufacturing method of a decorative sheet using the same.

[0008] SOLUTION TO PROBLEM

[0009] The present application provides a photocurable composition comprising a urethane (meth)acrylate oligomer, a (meth)acrylate monomer, and a photoinitiator.

[0010] The present application provides a manufacturing method of a decorative sheet, the method comprising: a step of forming a coating film by applying a photocurable composition on a substrate; a first curing step of pre-gelling the formed coating film; a second curing step of irradiating an excimer lamp; and a third curing step of irradiating a mercury lamp or a metal lamp.

[0011] Effects of the Invention

[0012] The photocurable composition of the present application does not use an organic solvent, and can be applied to an environmentally friendly raw material such as PETG (glycol modified Polyethylene Terephthalate (PET)), APET (amorphous PET), rPET (recycled PET), etc., thereby being able to provide an environmentally friendly decorative sheet. In addition, according to the manufacturing method of the present application, a non-gloss effect is specifically achieved without using a matting agent, and irregular defects generated on the surface of the decorative sheet can be minimized. DETAILED DESCRIPTION

[0013] Hereinafter, the present application will be described. However, the present application is not limited only to the following description, and each component can be variously modified or selectively mixed as needed. Therefore, it should be understood that all modifications, equivalents, or alternatives included within the idea and technical scope of the present application are encompassed.

[0014] The "weight average molecular weight" used in the present application is measured by a general method known in the art, for example, it can be measured by a GPC (gel permeation chromatograph) method. The "viscosity" is measured by a general method known in the art, for example, it can be measured using a brookfield viscometer. The "glass transition temperature" is measured by a general method known in the art, for example, it can be measured by a TMA (thermomechanical analysis) or a DSC (differential scanning calorimetry) method.

[0015] <Photocurable composition>

[0016] The photocurable composition of the present application contains a urethane (meth)acrylate oligomer, a (meth)acrylate monomer, and a photoinitiator. The photocurable composition of the present application can further contain additives known in the art within a range not impairing the effects of the present application. As the above additives, an adhesion enhancer, an antioxidant, a lubricant, a leveling agent, a surfactant, an antifoaming agent, a slip agent, a solvent, a wetting agent, a light stabilizer, a stain-proofing agent, a softening agent, a thickening agent, a polymer, and the like can be used.

[0017] urethane (meth)acrylate oligomer

[0018] The photocurable composition of the present application contains a urethane (meth)acrylate oligomer. The urethane (meth)acrylate oligomer, as a main resin component for forming a coating film, controls the crosslinking density of the entire coating film, thereby performing the role of imparting processability, hardness, and durability to the coating film.

[0019] The above urethane (meth)acrylate oligomer can be prepared by the reaction of a hydroxyl group-containing (meth)acrylate compound with an isocyanate compound.

[0020] As the above hydroxyl group-containing (meth)acrylate compound, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acryloyl phosphate, 2-(meth)acryloyloxyethyl-2-hydroxypropyl phthalate, glycerol di(meth)acrylate, 2-hydroxy-3-(meth)acryloyloxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate, dipentaerythritol penta(meth)acrylate, caprolactone-modified 2-hydroxyethyl (meth)acrylate, cyclohexane dimethanol mono(meth)acrylate, and the like can be used.

[0021] As the above isocyanate compound, aromatic, aliphatic, or aliphatic cyclic polyisocyanates can be used, for example, toluene diisocyanate, diphenylmethane diisocyanate, hydrogenated diphenylmethane diisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate, hydrogenated xylene diisocyanate, xylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, tetramethylxylene diisocyanate, isophorone diisocyanate, norbornene diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, phenylene diisocyanate, lysine diisocyanate, naphthalene diisocyanate, and the like polyisocyanates, or urethane prepolymers containing terminal isocyanate groups prepared by reacting the polyisocyanates thereof with polyols, and the like can be used.

[0022] The urethane (meth)acrylate oligomer can include a 3-functional urethane (meth)acrylate oligomer and a 4-functional urethane (meth)acrylate oligomer. In the case of including both of the above-mentioned urethane (meth)acrylate oligomers, the curing reaction speed and the crosslinking density are adjusted at the time of photocuring, thereby specifically realizing a matte effect of a coating film, and the surface tension of the coating film is adjusted to improve the smoothness of the coating film, and not only the appearance properties but also the mechanical properties such as chemical resistance and scratch resistance are improved, and a solvent can not be used, and thus an environmentally friendly composition can be provided.

[0023] The weight average molecular weight of the above-mentioned 3-functional urethane (meth)acrylate oligomer is 1,000 to 4,000 g / mol, for example, can be 1,500 to 3,500 g / mol, the viscosity (60°C) is 1,500 to 4,000 cps, for example, can be 2,000 to 3,500 cps, and the solid content is 70 to 100%, for example, can be 80 to 100%. In the case where the above-mentioned 3-functional urethane (meth)acrylate oligomer has the weight average molecular weight, the viscosity, and the solid content in the above-mentioned ranges, the properties of the coating film such as hardness, chemical resistance, moisture resistance, scratch resistance, and heat resistance are excellent.

[0024] In the case where the weight average molecular weight of the above-mentioned 3-functional urethane (meth)acrylate oligomer is less than the above-mentioned range, the viscosity is too low, and thus the adhesion and the chemical resistance of the coating film can be reduced, and in the case where it exceeds the above-mentioned range, the crosslinking density is greatly increased, and thus the elasticity of the coating film is reduced, as a result, the chemical resistance, the stain resistance, the processability, and the scratch resistance can be reduced. In addition, in the case where the viscosity of the above-mentioned 3-functional urethane (meth)acrylate oligomer is less than the above-mentioned range, the viscosity is low, and thus the coating film is not formed or the adhesion and the chemical resistance of the coating film can be reduced, and in the case where it exceeds the above-mentioned range, the coating workability is deteriorated, and thus the appearance and the processability of the coating film can be reduced. In addition, in the case where the solid content of the above-mentioned 3-functional urethane (meth)acrylate oligomer is less than the above-mentioned range, the viscosity is too low, and thus the workability of the composition including the same can be reduced, and in the case where it exceeds the above-mentioned range, the viscosity is high, and thus the stability in the reaction is reduced, and the dispersion stability is deteriorated, and thus the appearance can be reduced.

[0025] The weight average molecular weight of the above-mentioned 4-functional urethane (meth) acrylate oligomer is 500 to 1,800 g / mol, for example, it can be 700 to 1,500 g / mol, the viscosity (25°C) is 1,000 to 3,000 cps, for example, it can be 1,500 to 2,500 cps, and the solid content is 70 to 100%, for example, it can be 80 to 100%. In the case where the above-mentioned 4-functional urethane (meth) acrylate oligomer has the weight average molecular weight, the viscosity, and the solid content in the above-mentioned ranges, the properties of the coating film such as the hardness, the chemical resistance, the moisture resistance, the scratch resistance, and the heat resistance are excellent.

[0026] In the case where the weight average molecular weight of the above-mentioned 4-functional urethane (meth) acrylate oligomer is less than the above-mentioned range, the viscosity is too low, and thus the adhesion and the chemical resistance of the coating film can be reduced, and in the case where it exceeds the above-mentioned range, the crosslinking density is greatly increased, and thus the elasticity of the coating film is reduced, as a result, the chemical resistance, the stain resistance, the processability, and the scratch resistance can be reduced. In addition, in the case where the viscosity of the above-mentioned 4-functional urethane (meth) acrylate oligomer is less than the above-mentioned range, the viscosity is low, and thus the coating film is not formed or the adhesion and the chemical resistance of the coating film can be reduced, and in the case where it exceeds the above-mentioned range, the coating workability is deteriorated, and thus the appearance and the processability of the coating film can be reduced. In addition, in the case where the solid content of the above-mentioned 4-functional urethane (meth) acrylate oligomer is less than the above-mentioned range, the viscosity is too low, and thus the workability of the composition containing it can be reduced, and in the case where it exceeds the above-mentioned range, the viscosity is high, and thus the stability in the reaction is reduced, and the dispersion stability is deteriorated, and thus the appearance can be reduced.

[0027] The above-mentioned urethane (meth) acrylate oligomer is contained in an amount of 25 to 60% by weight, for example, it can be contained in an amount of 30 to 55% by weight, relative to the total weight of the photocurable composition. As one example, the above-mentioned 3-functional urethane (meth) acrylate oligomer is contained in an amount of 30 to 50% by weight, for example, it can be contained in an amount of 35 to 45% by weight, and the above-mentioned 4-functional urethane (meth) acrylate oligomer is contained in an amount of 0.5 to 10% by weight, for example, it can be contained in an amount of 1 to 8% by weight, relative to the total weight of the coating composition. In the case where the content of the urethane (meth) acrylate oligomer falls within the above-mentioned range, the appropriate crosslinking density is maintained, and thus the chemical resistance and the weather resistance of the coating film can be improved.

[0028] In the case where the content of the above-mentioned 3-functional urethane (meth)acrylate oligomer is less than the range described above, the viscosity is low, resulting in a decrease in crosslinking density, and thus the chemical resistance, weather resistance, and adhesion can be decreased, and in the case where it exceeds the range described above, the viscosity of the composition is high, and thus the workability is deteriorated, and thus the appearance of the coating film can be deteriorated. In addition, in the case where the content of the above-mentioned 4-functional urethane (meth)acrylate oligomer is less than the range described above, the viscosity is low, resulting in a decrease in crosslinking density, and thus the chemical resistance, weather resistance, and adhesion can be decreased, and in the case where it exceeds the range described above, the viscosity of the composition is high, and thus the workability and the flowability of the paint are deteriorated, and thus the appearance of the coating film and the water resistance can be deteriorated.

[0029] (meth)acrylate monomer

[0030] The photocurable composition of the present application contains a (meth)acrylate monomer. The (meth)acrylate monomer functions as a crosslinking agent that adjusts the crosslinking density between high molecules, and functions to impart hardness, adhesion, processability, and chemical resistance to the coating film.

[0031] The above-mentioned (meth)acrylate monomer can be a (meth)acrylate monomer having 3 or less functionality. For example, the above-mentioned (meth)acrylate monomer having 3 or less functionality can be a (meth)acrylate monomer having 3 functionality, a (meth)acrylate monomer having 2 functionality, a (meth)acrylate monomer having 1 functionality, or a mixture thereof. As one example, the above-mentioned (meth)acrylate monomer having 3 or less functionality can include a (meth)acrylate monomer having 3 functionality, a (meth)acrylate monomer having 2 functionality, and a (meth)acrylate monomer having 1 functionality.

[0032] As non-limiting examples of the above-mentioned (meth)acrylate monomer having 3 functionality, there are trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, and the like, which can be used alone or in a mixture of two or more kinds.

[0033] As non-limiting examples of the above-mentioned (meth)acrylate monomer having 2 functionality, there are 1,6-hexane diol di(meth)acrylate, Polyethylene glycol 400 Diacrylate, and the like, which can be used alone or in a mixture of two or more kinds.

[0034] As non-limiting examples of the above 1-functional (meth)acrylate monomer, tetrahydrofurfuryl (meth)acrylate, methyl 2-allyloxymethyl (meth)acrylate, isobornyl (meth)acrylate, benzyl acrylate, and the like can be given, which can be used alone or in a mixture of two or more kinds.

[0035] As another example, the above (meth)acrylate monomer can include a (meth)acrylate monomer containing a hydroxyl group, a (meth)acrylate monomer not containing a hydroxyl group, or a mixture thereof. As non-limiting examples of the above (meth)acrylate monomer containing a hydroxyl group, 2-hydroxyethyl acrylate, 2-hydroxymethyl methacrylate, hydroxypropyl acrylate, hydroxypropyl methacrylate, hydroxybutyl acrylate, hydroxybutyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, 2-hydroxy-3-phenoxypropyl acrylate, hydroxypivalic acid neopentyl glycol diacrylate (HPNDA), tri(2-hydroxyethyl)isocyanurate triacrylate (THEICTA), pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, dipentaerythritol polyacrylate, and the like can be given, which can be used alone or in a mixture of two or more kinds. As non-limiting examples of the above (meth)acrylate monomer not containing a hydroxyl group, trimethylolpropane tri(meth)acrylate, ethoxylated trimethylolpropane tri(meth)acrylate, propoxylated trimethylolpropane tri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate, and the like can be given, which can be used alone or in a mixture of two or more kinds.

[0036] As the above (meth) acrylate monomer, a monomer having a molecular weight of 100 to 700 g / mol can be used, for example, a monomer having a molecular weight of 150 to 650 g / mol can be used. In the case where the molecular weight of the above (meth) acrylate monomer is less than the above range, the crosslinking efficiency is lowered, and the molecular weight is too small, so that the hardness and durability of the coating film are lowered, and stains occur at the time of work, and the wettability is lowered, so that the appearance is lowered. On the contrary, in the case where the above range is exceeded, the coating film hardness is increased and becomes brittle, so that the mechanical properties, the adhesion, and the reflectance are lowered.

[0037] As the above (meth) acrylate monomer, a monomer having a glass transition temperature of 5 to 100°C, for example, 10 to 90°C, and a viscosity (25°C) of 5 to 120 cps, for example, 10 to 110 cps can be used. In the case where the glass transition temperature of the above (meth) acrylate monomer is less than the above range, the crosslinking efficiency is lowered, so that the mechanical properties are lowered, and in the case where the above range is exceeded, the hardness of the coating film becomes brittle, so that the adhesion and the gloss are lowered. In the case where the viscosity of the above (meth) acrylate monomer is less than the above range, the viscosity is low, so that the coating film is not formed or the adhesion and the chemical resistance of the coating film are lowered, and in the case where the above range is exceeded, the paint workability is deteriorated, so that the appearance and the processability of the coating film are lowered.

[0038] The content of the above (meth) acrylate monomer is 25 to 65% by weight, for example, can be 35 to 60% by weight, based on the total weight of the paint composition. As one example, 5 to 15% by weight of a 3-functional (meth) acrylate monomer, for example, can be contained, 7 to 13% by weight of a 3-functional (meth) acrylate monomer, 20 to 40% by weight of a 2-functional (meth) acrylate monomer, for example, can be contained, 25 to 35% by weight of a 2-functional (meth) acrylate monomer, and 3 to 10% by weight of a 1-functional (meth) acrylate monomer, for example, can be contained, 5 to 8% by weight of a 1-functional (meth) acrylate monomer, based on the total weight of the paint composition.

[0039] In the case where the content of the above-mentioned 3-functional (meth)acrylate monomer is less than the range described above, the viscosity is low, resulting in a decrease in crosslinking density, and as a result, the crosslinking degree, adhesion, and coating workability can decrease, and in the case where it exceeds the range described above, the viscosity is too high, resulting in a decrease in flexibility of the coating film, and thus the gloss can decrease. In the case where the content of the above-mentioned 2-functional (meth)acrylate monomer is less than the range described above, the viscosity of the coating composition increases, and thus the flowability and leveling property can decrease, and in the case where it exceeds the range described above, the viscosity of the composition is very low, resulting in a decrease in curability, and as a result, the workability and adhesion can decrease. In addition, in the case where the content of the above-mentioned 1 -functional (meth)acrylate monomer is less than the range described above, the viscosity of the coating composition increases, and thus the adhesion can decrease, and in the case where it exceeds the range described above, the viscosity of the composition is very low, resulting in a decrease in curability, and as a result, the workability and hardness can decrease.

[0040] The above-mentioned 3-functional (meth)acrylate monomer, 2-functional (meth)acrylate monomer, and 1 -functional (meth)acrylate monomer can be used in a mixture of 1 :2 to 5:0.1 to 2 by weight, for example, 1 :3 to 4:0.5 to 1 by weight. In the case where the mixing ratio of the three (meth)acrylate monomers falls within the range described above, an appropriate crosslinking density is maintained, and thus the mat effect is specifically realized and the appearance is excellent, and in addition, the chemical resistance and weather resistance of the coating film can be improved.

[0041] photoinitiator

[0042] The photocurable composition of the present application contains a photoinitiator. The above-mentioned photoinitiator is a component that exerts the action of initiating photopolymerization by excitation with ultraviolet rays (UV) or the like, and a photoinitiator generally used in the art can be used without limitation.

[0043] As non-limiting examples of the photoinitiator which can be used, Irgacure 184, Irgacure 369, Irgacure 651, Irgacure 819, Irgacure 907, benzion alkyl ether, benzophenone, benzyl dimethyl katal, hydroxycyclohexyl phenylacetone, chloroacetophenone, 1,1-dichloro acetophenone, diethoxy acetophenone, hydroxy acetophenone, 2-choro thioxanthone, 2-ethyl anthraquinone, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy-2-methyl-1-phenyl-1-propanone, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl-1-propanone, bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide, methyl benzoyl formate, and the like can be mentioned, and they can be used alone or in a mixture of two or more kinds.

[0044] In the present application, the content of the above-mentioned photoinitiator can be 1 to 10% by weight based on the total weight of the photocurable composition. If the content of the above-mentioned photoinitiator is less than 1% by weight, the strength and adhesion of the coating film will be reduced due to the decrease in curability or uncured, and in addition, wrinkles will be generated due to the uncured coating film. On the other hand, if the content of the above-mentioned photoinitiator exceeds 10% by weight, contamination by the unreacted photoinitiator or low polymerization degree will result in the decrease in adhesion.

[0045] additive

[0046] In addition to the aforementioned components, the photocurable composition of the present application can use, without limitation, additives known in the art, within a range that does not impair the effects of the present application.

[0047] As additives that can be used, there are surface conditioning agents (e.g., polyethersiloxane copolymer), surface property conditioning agents (e.g., acryl-functional polydimethylsiloxane), and the like. These can be used individually or in a mixture of two or more. In the present application, the content of the aforementioned additives can be appropriately adjusted within a range known in the art. As one example, the amount of each of the aforementioned additives used can be 0.1 to 5% by weight, based on the total weight of the photocurable composition.

[0048] In addition, the photocurable composition of the present application can contain a pigment. In order to impart a desired color (coloration) to the paint, pigments can be used, and organic pigments, inorganic pigments, metallic pigments, Al-paste, pearl, and the like can be used without limitation, and these can be used individually or in a mixture of two or more. As non-limiting examples of pigments that can be used, there are azo-based pigments, phthalocyanine-based pigments, iron oxide-based pigments, cobalt-based pigments, carbonate-based pigments, sulfate-based pigments, silicate-based pigments, chromate-based pigments, and the like, for example, titanium dioxide, zinc oxide, bismuth vanadate, cyanine green, carbon black, red iron oxide, yellow iron oxide, navy blue, phthalocyanine blue, and mixtures of two or more of these, and the like.

[0049] The content of the aforementioned pigments is not particularly limited, and can be 0.1 to 20% by weight, based on the total weight of the photocurable composition, for example, 0.5 to 15% by weight. In the case where the content of the aforementioned pigments is less than the aforementioned range, the hiding power of the film produced can be insufficient, and in the case where it exceeds the aforementioned range, the stability, mechanical properties, and adhesion of the composition can be reduced.

[0050] <Method for manufacturing decorative sheet>

[0051] The method for manufacturing a decorative sheet according to the present application includes a step of applying a photocurable composition to a substrate to form a coating film, a first curing step of pre-gelling the coating film formed, a second curing step of irradiating an excimer lamp, and a third curing step of irradiating a mercury lamp or a metal lamp.

[0052] The above substrate can include PET (polyethylene terephthalate), PETG (glycol modified PET), APET (amorphous PET), rPET (recycled PET), PBT (polybutylene terephthalate), PP (polypropylene), PE (polyethylene), PVC (poly vinyl chloride), PMMA (poly methylmethacrylate), ABS (acrylonitrile-butadiene-styrene), PC (polycarbonate), SAN (styrene-acrylonitrile copolymer), and mixtures thereof.

[0053] The above photocurable composition contains urethane (meth)acrylate oligomer, (meth)acrylate monomer, and photoinitiator, as described in detail above.

[0054] The above photocurable composition can be coated on the above substrate at a thickness of 5 to 30 μm, for example, at a thickness of 10 to 25 μm. In the case where the thickness of the photocurable composition is less than the above range, the mechanical properties of the coating film and the pattern formation can be deteriorated, and in the case where it exceeds the above range, the curing is not sufficient, and thus the appearance and the pattern formation can be lowered or the coating film can be peeled off.

[0055] The above first curing step is a pre-gelling step, in which the above formed coating film is irradiated with UV LED (365 nm, 395 nm, etc.) or Ga lamp. The lamp power can be 25 to 100%.

[0056] In the above second curing step, the above coating film is irradiated with an excimer lamp. The excimer lamp is irradiated, and thus the micro-folding effect can be realized on the surface of the coating film, thereby providing a no-light effect. The wavelength of the excimer lamp can be a single wavelength (for example, 172 nm), the oxygen concentration can be 50 to 500 ppm, and the lamp power can be 25 to 100%.

[0057] The coating film is irradiated with a mercury lamp or a metal lamp in the above-mentioned third curing step. The wavelength of the mercury lamp can be 200 to 400 nm, and the irradiation amount can be 100 to 300 mJ / cm 2 .

[0058] By the above-mentioned first to third curing steps, the speed of the curing reaction and the crosslinking density are adjusted at the time of photocuring to specifically realize the matte effect of the coating film, and the surface tension of the coating film is adjusted to improve the smoothness and uniformity of the coating film, not only improving the appearance properties, but also improving the mechanical properties such as chemical resistance and scratch resistance, and a solvent can not be used, thus enabling an environmentally friendly composition to be provided.

[0059] The present application is further specifically described below through examples. However, the following examples are only used to help understand the present application, and the scope of the present application is not limited to the examples in any sense.

[0060] [Examples 1-17]

[0061] The photocuring-type coating compositions of the respective examples were prepared in accordance with the compositions described in Tables 1 and 2 below.

[0062] [Comparative Examples 1-6]

[0063] The photocuring-type coating compositions of the respective comparative examples were prepared in accordance with the compositions described in Table 3 below.

[0064] [Table 1]

[0065]

[0066]

[0067] [Table 2]

[0068]

[0069]

[0070] [Table 3]

[0071]

[0072]

[0073] 3-functional acrylate oligomer 1: Mw 2,700, solids 100%, viscosity (60°C) 3,000 cps 3-functional acrylate oligomer 2: Mw 1,200, solids 100%, viscosity (60°C) 1,700 cps 3-functional acrylate oligomer 3: Mw 3,900, solids 100%, viscosity (60°C) 3,800 cps 3-functional acrylate oligomer 4: Mw 800, solids 100%, viscosity (60°C) 1,350 cps 3-functional acrylate oligomer 5: Mw 4,750, solids 100%, viscosity (60°C) 4,600 cps

[0074] 4-functional acrylate oligomer 1: Mw 1,300, solids 100%, viscosity (25°C) 2,300 cps

[0075] 4-functional acrylate oligomer 2: Mw 600, solids 100%, viscosity (25°C) 1,450 cps

[0076] 4-functional acrylate oligomer 3: Mw 1,650, solids 100%, viscosity (25°C) 2,500 cps

[0077] 4-functional acrylate oligomer 4: Mw 420, solids 100%, viscosity (25°C) 870 cps

[0078] 4-functional acrylate oligomer 5: Mw 1,920, solids 100%, viscosity (25°C) 2,700 cps

[0079] 5-functional acrylate oligomer 1: Mw 3,200, solids 100%, viscosity (25°C) 7,200 cps

[0080] 6-functional acrylate oligomer 1: Mw 3,900, solids 100%, viscosity (25°C) 8,000 cps

[0081] Monomer 1: Trimethylolpropane triacrylate

[0082] Monomer 2: 1,6-hexanediol diacrylate

[0083] Monomer 3: Polyethylene glycol 400 diacrylate

[0084] Monomer 4: Isobornyl acrylate

[0085] Photoinitiator 1: 1-hydroxycyclohexyl-phenyl ketone

[0086] Photoinitiator 2: 2,4,6-trimethylbenzoyl-diphenyl phosphine oxide

[0087] Additive 1: Polyether siloxane copolymer

[0088] Additive 2: Acrylic functional polydimethylsiloxane

[0089] [Experimental Example: Physical Property Evaluation]

[0090] The physical properties of decorative sheets produced using the photocurable compositions produced in each of the examples and comparative examples were evaluated by the following method, and the results are shown in Tables 4 to 6 below.

[0091] test piece production

[0092] The photocurable compositions produced in each of the examples and comparative examples were coated (at a thickness of 15 μm) on a decorative film (PETG) 10 mm x 10 mm substrate and subjected to photocuring (first step: using a UV LED, wavelength 395 nm, lamp power 100%, speed 20 m / min; second step: using an excimer lamp, wavelength 172 nm, lamp power 30%, speed 20 m / min, oxygen concentration 100 ppm; and third step: using a mercury lamp (Hg Lamp), wavelength 200 to 400 nm, irradiation amount 250 mJ / cm 2 , speed 20 m / min) to form decorative sheets.

[0093] appearance

[0094] Observation was made as to whether there were defects recognizable by the naked eye such as discoloration, reduction in gloss, etc. Evaluation was made in terms of excellent ( ), good (0), fair (Δ), and poor (X).

[0095] adhesion

[0096] A cross cut tape test was performed in accordance with ASTM D3359 and evaluation was made. A cross cutter was used to draw 1 mm x 1 mm crosshatched lines on the surface in 10 rows in the horizontal direction and 10 rows in the vertical direction, for a total of 100 squares, and the number of squares in which the coating film remained adhered when a NICHIBAN tape was attached and peeled off was counted to evaluate the adhesion.

[0097] [Evaluation Criteria]

[0098] Excellent ( ): 99 squares or more of the coating film remained adhered

[0099] Good (O): Adhesion of the coating film was maintained for 95 or more scales and less than 99 scales

[0100] Fair (Δ): Adhesion of the coating film was maintained for 85 or more scales and less than 95 scales

[0101] Poor (X): Adhesion of the coating film was maintained for less than 85 scales

[0102] gloss

[0103] The surface gloss was confirmed from the measurement angles of 60° and 85° using a gloss meter according to ASTM D2457.

[0104] pencil hardness

[0105] The maximum hardness without flaws was confirmed after 3 times of reciprocation at an angle of 45° with a load of 750 g using a pencil hardness tester according to ASTM D3363.

[0106] cold and hot cycle resistance test

[0107] The test piece was left at 80 ± 2°C, 95% RH for 4 hours, and then the temperature condition was changed to -40 ± 2°C, 95% RH and left for 4 hours. The above series of processes were repeated 5 times, and after left at room temperature for 1 hour, whether there was obvious discoloration, fading, swelling, cracking, reduction in gloss, and abnormal adhesion was observed. The evaluation was performed with excellent (O), good (O), fair (Δ), and poor (X).

[0108] stain resistance

[0109] The coffee was left as a residual on the UV-coated surface, washed with water after 24 hours, and the contamination state was confirmed with the naked eye.

[0110] [Evaluation Criteria]

[0111] 5: No change

[0112] 4: Slight change (only when reflected under light)

[0113] 3: Moderate change (when viewed from multiple visual directions)

[0114] 2: Large change in color or gloss (Swelling, Cracking, Blistering)

[0115] 1: Severe change

[0116] chemical resistance

[0117] Drops of 1% NaCO3, 5% CH3COOH, 1% HC1, Petroleum Benzene were added, and after 6 hours, the state was confirmed with the naked eye after washing with water.

[0118] [evaluation criteria]

[0119] 5: no change

[0120] 4: slight change (only when reflected under light)

[0121] 3: moderate change (when viewed from multiple viewing directions)

[0122] 2: large change in color or gloss (Swelling, Cracking, Blistering)

[0123] 1: severe change

[0124] [Table 4]

[0125]

[0126] [Table 5]

[0127]

[0128]

[0129] [Table 6]

[0130]

[0131] From the results of Tables 1 to 6 above, it can be confirmed that in the case of the decorative sheet manufactured from the photocurable composition according to Examples 1 to 17 of the present application, the measured physical property items as a whole showed excellent physical properties. In contrast, in the case of the decorative sheet manufactured from the photocurable composition of Comparative Example 1 in which the weight average molecular weight of the 3-functional urethane acrylate oligomer deviated from the range of the present application, Comparative Example 2; Comparative Example 3 in which the weight average molecular weight of the 4-functional urethane acrylate oligomer deviated from the range of the present application, Comparative Example 4; Comparative Example 5 in which a 5-functional urethane acrylate oligomer was used instead of the 4-functional urethane acrylate oligomer; and Comparative Example 6 in which a 6-functional urethane acrylate oligomer was used instead of the 4-functional urethane acrylate oligomer, inferior physical properties were shown in appearance, adhesion, gloss, pencil hardness, and chemical resistance compared to the Examples.

Claims

1. A photocurable composition, characterized by, comprising a urethane (meth)acrylate oligomer, a (meth)acrylate monomer, and a photoinitiator, the urethane (meth)acrylate oligomer comprises a 3-functional urethane (meth)acrylate oligomer and a 4-functional urethane (meth)acrylate oligomer, the photocurable composition comprises 30 to 50 wt% of the 3-functional urethane (meth)acrylate oligomer, 0.5 to 10 wt% of the 4-functional urethane (meth)acrylate oligomer, 25 to 65 wt% of the (meth)acrylate monomer, and 1 to 10 wt% of the photoinitiator, relative to the total weight of the photocurable composition, the weight average molecular weight of the 3-functional urethane (meth)acrylate oligomer is 1,000 to 4,000 g / mol, and the weight average molecular weight of the 4-functional urethane (meth)acrylate oligomer is 500 to 1,800 g / mol.

2. The photocurable composition according to claim 1, characterized by, the 3-functional urethane (meth)acrylate oligomer has a viscosity of 1,500 to 4,000 cps at 60°C, and a solid content of 70 to 100%.

3. The photocurable composition according to claim 1, characterized by, the 4-functional urethane (meth)acrylate oligomer has a viscosity of 1,000 to 3,000 cps at 25°C, and a solid content of 70 to 100%.

4. The photocurable composition according to claim 1, characterized by, the (meth)acrylate monomer comprises a 3-functional (meth)acrylate monomer, a 2-functional (meth)acrylate monomer, and a 1-functional (meth)acrylate monomer, the mixing ratio of the 3-functional (meth)acrylate monomer, the 2-functional (meth)acrylate monomer, and the 1-functional (meth)acrylate monomer is 1:2 to 5:0.1 to 2 by weight.

5. A method for manufacturing a decorative sheet, characterized by, comprising: a step of applying a photocurable composition on a substrate to form a coating film, a first curing step of performing pre-gelation by irradiating a UV LED or a Ga lamp on the formed coating film, a second curing step of irradiating an excimer lamp, and a third curing step of irradiating a mercury lamp or a metal lamp, the photocurable composition is the photocurable composition according to any one of claims 1 to 4.

6. The method for manufacturing a decorative sheet according to claim 5, characterized by, in the first curing step, the wavelength of the UV LED is 365 nm or 395 nm, and the lamp power is 25 to 100%, in the second curing step, the wavelength of the excimer lamp is 172 nm, the oxygen concentration is 50 to 500 ppm, and the lamp power is 25 to 100%, In the above third curing step, the wavelength of the mercury lamp is 200 to 400 nm, and the irradiation amount is 100 to 300 mJ / cm 2 .

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