KR20000021808A - Ultraviolet curable composition having improved writing property and white board film utilizing it - Google Patents

Abstract

PURPOSE: The ultra violet curable composition is provided which has an improved scratch resistance, chemical resistance, thermal resistance and solvent resistance, writing property and clearance property, CONSTITUTION: A composition comprises 30-90 weight % of ultra violet curable acrylateoligomer, 1-30 weight % of ultra violet reactive diluent, 0.1-10 weight % of photopolymerization initiator, 0.05-20 weight % of leveling agent and residue of solvent. Thus, an ultra violet curable composition containing 73 weight parts of 6-functional aliphatic urethane acrylate oligomer, 10.0 weight parts of trimethylolpropane triacrylate, 5 weight parts of methacrylated acidic compounds, 5 weight parts of hydroxy ethyl acrylate, 6.0 weight parts of alpha-hydroxy-ketone, 1.0 weight parts of leveling agent and residue of isopropyl alcohol is coated on polyethylene terephthalate film, dried at 50°C for 20 seconds, and irradiated by ultra violet to give the title film.

Description

UV curable composition with improved clarity and whiteboard film using same

The present invention relates to an ultraviolet curable composition and a film for a whiteboard using the same, and more particularly, the adhesion to the substrate and the surface strength are improved, and the ultraviolet curable composition and the whiteboard or the copyboard using the same have excellent clarity and erasability. It relates to the film for use.

Whiteboards are generally laminated on a substrate with about 200 μm of white polyvinyl chloride film and about 50 μm of polyethylene terephthalate film or by diluting polyester resin with titanium oxide in an organic solvent and then applying it onto the substrate. It is prepared by leveling and curing using a polyethylene terephthalate film or the like and then peeling off the film used for leveling. However, such a manufacturing method has a disadvantage that the curing time is long and the process is complicated and the productivity is low.

On the other hand, polyethylene terephthalate film is known to be lightweight but hard and good workability, and also good clarity and erasability to the marker pen which is a writing instrument for whiteboard. However, since polyethylene terephthalate film has a low surface hardness and is easy to be scratched, scratches occur when repeated writing and erasing are repeated several times. Such a scratch will result in the white board not being erased cleanly even with the eraser.

Conventionally, many hard coating methods have been proposed for improving the surface hardness of a polyester film containing polyethylene terephthalate to impart scratch resistance. For example, a method of applying a thermosetting silicone resin having a polysiloxane structure by applying a melamine resin, a urethane resin, an acrylic resin, an alkyd resin, or the like, and a thermosetting silicone resin, a method of applying an inorganic silicone oxide, or a polyfunctional acrylic resin The method of hardening by irradiating an ultraviolet-ray, using as a main binder is known.

However, the thermal curing method of the above method has the following disadvantages.

That is, it is hardly used at high temperatures, so it cannot be used for materials that are weak to heat, and because of the use of solvents, environmental problems such as air pollution occur, a lot of energy is consumed to cure, and a large area is required to install a curing device. It takes a long time to cure, there is a problem that productivity is lowered.

On the other hand, the UV curing method can overcome the disadvantages of the above-mentioned thermosetting method, and has excellent storage stability and can be cured within a few seconds at room temperature compared to the thermosetting method, so that the productivity is high and the deformation of the cured film is small. In the case of the film produced through the wear resistance, water resistance, solvent resistance, heat resistance, weather resistance and the like has an advantage. However, in the case of the polyester film prepared by applying the UV curing method, the surface hardness is somewhat insufficient to be used as a film for whiteboard, and there is a problem in that the readability and erasability to the macapen is poor.

In addition, the ultraviolet curing method has a disadvantage in that the adhesion between the composition for the hard coating layer and the plastic substrate such as polyethylene terephthalate film cannot be maintained at a desirable level. Typically this problem has been solved by subjecting the film surface to a primer. However, it is unavoidable to lower productivity and increase production cost due to the addition of the primer layer forming process.

The technical problem to be achieved by the present invention is to provide a UV curable composition suitable for a hard coating layer for improving the scratch resistance, chemical resistance, solvent resistance, heat resistance, and tackiness and erasability of the base film.

Another technical problem to be achieved by the present invention is to provide a whiteboard film that can produce a whiteboard or copyboard in a simpler process.

In order to achieve the above technical problem, in the present invention, 30 to 90% by weight of the ultraviolet curable acrylate oligomer, 1 to 30% by weight of UV reactive diluent, 0.1 to 10% by weight of photopolymerization initiator, 0.05 to An ultraviolet curable composition comprising 20% by weight of a leveling agent and a residual amount of a solvent,

The oligomer is a six functional aliphatic urethane acrylate, the ultraviolet reactive diluent is a monofunctional or polyfunctional acrylate monomer or a mixture thereof, and the leveling agent is an ultraviolet curable non-silicone compound, characterized in that Is provided.

In order to achieve the above another technical problem, the present invention provides a film for whiteboard using the composition.

Hereinafter, the present invention will be described in more detail.

In general, the oligomer is a compound having a molecular weight of 500 to 5000 may be diluted with each monomer according to the viscosity and physical properties, it is also a component that determines the main characteristics of the final product. The oligomers contained in the ultraviolet curable composition according to the present invention are composed of acrylates or methacrylates at the ends thereof, and urethane acrylate, epoxy acrylate, polyester acrylate, acrylic acrylate, and silicone acrylate depending on the structure of the main chain. Or amino acrylates and the like. Specifically, the characteristics of each oligomer are as follows.

Urethane acrylates include urethane bonds as repeating units and typically have flexible physical properties. There are many different types, and depending on the type of isocyanate, it is divided into aliphatic urethane acrylate and aromatic urethane acrylate. Aliphatic urethane acrylates are of the yellowing type and have 2 to 6 functional groups. Aromatic urethane acrylates are yellowing type and have fast reactivity. Epoxy acrylate contains an epoxy bond in the main chain and causes yellowing, but has excellent hardness, solvent resistance and curability. Polyester acrylate is low in viscosity and excellent in weather resistance. Acrylic acrylate has good weather resistance and water resistance, in particular good adhesion to all materials. Amino acrylate is used as a curing accelerator to improve the surface hardening and has the disadvantage of causing yellowing. Silicone acrylates are used as wetting agents, slip agents or release agents.

According to a preferred embodiment of the present invention, in order to maximize the surface hardness by improving the crosslinking density within the range of not yellowing, scratch resistance, abrasion resistance is improved, and does not adversely affect the flexibility of the various oligomers mentioned above Heterofunctional aliphatic urethane acrylates are selected. The content is preferably 30 to 90% by weight based on the total composition. If the content is less than 30% by weight, the surface hardness is not sufficient, and if the content exceeds 90% by weight, the viscosity increases, and when applied to the substrate, the smoothness of the coating film or the cured film decreases, making it difficult to obtain a uniform cured film and the flexibility of the cured film. It is lowered and is not preferable.

In the present invention, the ultraviolet reactive diluent is a monomer having a molecular weight of 500 or less, and is mainly used for the purpose of lowering the viscosity of the ultraviolet curable composition. These monomers exhibit the following characteristics depending on the number of functional groups.

First, while monofunctional (monofunctional) monomers have excellent adhesion and flexibility to the substrate, they have a disadvantage of low viscosity and viscosity when used in excess. In the present invention, as the monofunctional monomer, hydroxy ethyl acrylate having excellent curability is preferably used to enhance adhesion to the substrate.

In addition, bifunctional monomers are most commonly used because of their proper viscosity, reactivity and flexibility, and trifunctional monomers have the advantage of high hardness and reactivity. In addition, the 4 to 6 functional monomers have excellent reactivity and high crosslinking density, and thus have excellent hardness, but have disadvantages of low flexibility.

According to the present invention, it is preferable to mix and use two or more acrylate monomers among the various monomers in order to improve the crosslinking density and the curing rate within a range that does not impair flexibility. For example, trifunctional pentaerythritol triacrylate and tetrafunctional pentaerythritol tetraacrylate are mixed or trifunctional trimethylol propane triacrylate is added to the mixture. By using such a mixture of mono / polyfunctional monomers, the crosslinking density and curing rate of the hard coating can be preferably maintained.

At this time, the mono / polyfunctional acrylate monomer is preferably in the content of 1 to 30% by weight based on the total composition. If the content is less than 1% by weight, there is almost no dilution effect, resulting in a problem of high viscosity. When the content is more than 30% by weight, flexibility decreases, shrinkage of the cured layer occurs, and adhesion to the substrate decreases.

The photopolymerization initiator is responsible for initiating the reaction by absorbing ultraviolet rays to generate free radicals, and the kind thereof is not particularly limited. The initiator varies the wavelength range of absorption according to the type, and there are yellow type and low yellow type. In general, to absorb a wavelength of 300 to 360nm, and to absorb various wavelengths to promote reactivity, two or more initiators are used together. In addition, when the coating thickness is thin, the higher the content, the better the reactivity, and when the coating thickness is thick, the total curing rate increases as the content decreases.

In the present invention, an α-hydroxyalkylphenone-based material is preferable for improving reactivity among commonly used low yellowing type initiators. Specifically, 1-Hydroxy-cyclohexyl-phenyl Ketone or α, α-dimethoxy-α-hydroxyacetophenone (α, α-Dimethoxy-α-hydroxyacetophenone) Preference is given to mixtures of one or two substances. The content of the photopolymerization initiator is preferably 0.1 to 10% by weight based on the total composition, but when the content is less than 0.1% by weight, the reactivity is slow. On the other hand, when the content is more than 10% by weight, the reactivity is increased but the surface hardness is decreased. there is a problem.

Meanwhile, the UV curable composition may include a leveling agent for increasing the smoothness of the paint, a wetting agent for reducing the surface tension of the paint, and a wetting agent for improving the wettability to the base film, an ultraviolet stabilizer, or other materials. have.

The ultraviolet curable composition of this invention is characterized by including an ultraviolet curable non-silicone compound. This material acts to give good wettability and leveling properties without migration to the film surface due to the property of direct curing reaction with the oligomer backbone. In addition, the non-silicone is not a concern that adversely affects the readability to the maca pen, when using a silicone, there is a disadvantage that the surface tension of the cured coating film is lowered enough to sufficiently wet the ink of the marker. As an ultraviolet curing non-silicone type compound used for this invention, a modified acrylic resin or an acryl-styrene copolymer is preferable. The content is preferably 0.05 to 20% by weight based on the total weight of the composition, the side effect of lowering the surface hardness occurs when used in excess.

In addition, according to another aspect of the present invention, a so-called adhesion enhancer can be used to enhance the adhesion of the composition for hard coating layer to the base film. Due to the addition of the adhesion promoter, the composition according to the present invention can exhibit excellent adhesion to the base film without forming a primer layer. As the adhesion promoter, a methacrylated acidic compound having an acid value of 270 to 330 mgKOH / g is preferable. The content of the material is preferably 1 to 30% by weight, since the methacrylated acidic compound is added in excess of 30% by weight, which may cause stickiness of the surface.

The solvent contained in the ultraviolet curable composition of the present invention is generally selected in the art as a solvent used for film coating in consideration of compatibility and solubility with the composition components, and is not limited to any particular kind.

Hereinafter, the manufacturing method of the film for whiteboards using the ultraviolet curable composition by this invention is demonstrated.

The method for applying the ultraviolet curable composition according to the present invention to the base film may be adopted without particular limitation as long as it is a method commonly known in the art. For example, the shape of the base film in the air knife method, the gravure method, the reverse roll method, the kiss roll method, the spray method or the blade method And can be used arbitrarily selected according to the material. As for the thickness of a coating film, about 1-50 micrometers is suitable. If the thickness of the coating film is less than 1 µm, it is difficult to obtain a sufficient cured coating film. If the thickness of the coating film is more than 50 µm, it is difficult to use due to the disadvantage that the flexibility of the coating film is poor and brittle.

After applying the ultraviolet curable composition to the base film using the method described above, the cured coating film is formed by irradiating ultraviolet rays after heating and drying by irradiating hot air, infrared rays, far infrared rays, or the like, or irradiating ultraviolet rays immediately without such a drying process. . The type of ultraviolet lamp used for ultraviolet irradiation is also not particularly limited as long as it is commonly used. For example, a high pressure mercury lamp, an ultra high pressure mercury lamp, an electrodeless lamp, a metahalide lamp and the like can be used. The output of the lamp is preferably 60 to 240 W / cm, and the cured coating film is formed by irradiating ultraviolet rays while moving the film coated with the ultraviolet curable composition by a belt conveyor. The ultraviolet curable composition according to the present invention is hardly affected by oxygen, and thus can be cured in air without the need for an inert environment such as nitrogen. The distance between the ultraviolet lamp and the base film is used to adjust the amount of light at 30 to 300mm.

As described above, the UV curable composition of the present invention is hard-coated on one side of the polyethylene terephthalate film, and the opposite side is applied to a batikal board or steel by applying an adhesive or an adhesive to the other side, thereby making it easier to read. And a whiteboard or copyboard excellent in erasability can be produced.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the following examples are merely examples given to show the effects of the present invention, and the scope of the present invention is not limited by the following examples.

In the following Examples and Comparative Examples, the physical properties of the prepared scratch-resistant film was evaluated by the following method.

(1) pencil hardness

Under the conditions of Japanese Industrial Standards (JIS) JIS-K5400, evaluation was made using a pencil made by Steadler with a pencil hardness meter of Sheen. Pencil specifications used were 6B, 5B, 4B, 3B, 2B, B, HB, F, H, 2H, 3H, 4H, 5H, 6H, 7H, 8H, 9H.

(2) scratch resistance

Rubbing the coating film with a steel wool of 10 µm in diameter to visually observe whether scratches occurred was evaluated as defective or good.

(3) chemical resistance

After immersion in a 5% aqueous sodium hydroxide solution and a 5% aqueous hydrochloric acid solution at room temperature for 4 hours, the result was evaluated as poor or good according to the change of physical properties of the coating film.

(4) solvent resistance

After immersion for 48 hours in toluene, acetone, methyl ethyl ketone, methanol, isopropyl alcohol, butyl acetate and the like at room temperature, it was evaluated as poor or good according to the change of physical properties of the coating film.

(5) heat resistance

The temperature at which the cured film was melted was measured when 1 kg of the film on which the UV cured film was formed was pressed with a heat gradient and pressed for 2 seconds.

(6) readability

(1) After drawing a 1cm wide line with red, blue, and black markers on the UV cured film, it was left to stand for 1 week, and then it was observed whether the width of the line decreased.

A 1 cm wide line was drawn with red, blue, and black maca pens on the UV cured film, and left for 1 week, and then visually evaluated whether the eraser was erased with a white eraser.

(8) adhesion

After cross hatching the coating film at 1 mm intervals, the cellophane tape was attached and then peeled off to grasp the number remaining without peeling, and evaluated as defective or good.

<Example 1>

The UV curable composition having the composition shown below was coated on an untreated polyethylene terephthalate film (Skyrol, SKC Co., Ltd.) having a thickness of 100 μm using a 0.15 mm Meyer Bar, dried at 50 ° C. for 20 seconds, and then irradiated with an ultraviolet light (product manufactured by Fusion, USA) , F450) and an ultraviolet lamp (US Fusion company, electrodeless H-bulb) was irradiated with ultraviolet light on the film surface. The ultraviolet irradiation distance was 50 mm, and the belt speed was adjusted so that accumulated light amount might be 200 mJ / sq.cm. The coating film thickness of the ultraviolet curable resin layer formed in this way was 5 micrometers. The physical properties of the film produced as described above are measured and shown in Table 1.

6 functional aliphatic urethane acrylate oligomer 73.0 parts by weight

(Ebecryl 5129, manufactured by UCB Chemicals)

10.0 parts by weight of trimethylolpropane triacrylate

(SR 350, product of Sartomer)

5.0 parts by weight of methacrylated acidic compound

(Ebecryl 169, manufactured by UCB Chemicals)

5.0 parts by weight of hydroxyethyl acrylate

(HEA, manufactured by UCB Chemicals)

6.0 parts by weight of α-hydroxy ketone

(Irgacure 184, manufactured by Ciba-geigy)

1.0 part by weight of leveling agent

(HS-70, Union Carbide company)

50.0 parts by weight of isopropyl alcohol

<Example 2>

The UV curable composition having the following composition was applied onto an untreated polyethylene terephthalate film having a thickness of 125 μm using a 100 mesh gravure roll and dried at 50 ° C. for 20 seconds, followed by an ultraviolet irradiation device (F450, manufactured by Fusion, USA), and output 80 W. Ultraviolet rays were irradiated to the surface of the coated film using an ultraviolet lamp composed of four high-pressure mercury lamps / cm. The ultraviolet irradiation distance was 150 mm, and the belt speed was adjusted so that accumulated light amount might be 200 mJ / sq.cm. The coating film thickness of the ultraviolet curable resin layer formed in this way was 7 micrometers. The physical properties of the film produced as described above are measured and shown in Table 1.

67.5 parts by weight of a 6 functional aliphatic urethane acrylate oligomer

(Ebecryl 5129, manufactured by UCB Chemicals)

10.0 parts by weight of trimethylolpropane triacrylate

(TMPTA, manufactured by UCB Chemicals)

10.0 parts by weight of pentaerythritol tri / tetra acrylate mixture

(PETA, manufactured by UCB Chemicals)

5.0 parts by weight of methacrylated acidic compound

(Ebecryl 169, manufactured by UCB Chemicals)

6.0 parts by weight of α-hydroxyalkyl phenone

(Darocure 1173, manufactured by Ciba-geigy)

1.5 parts by weight of leveling agent

(HS-70, manufactured by UCB Chemicals)

50.0 parts by weight of isopropyl alcohol

<Example 3>

The UV curable composition having the composition shown below was applied onto an untreated polyethylene terephthalate film having a thickness of 100 μm using three reverse rolls and dried at 50 ° C. for 20 seconds, followed by an ultraviolet irradiation device (F450, manufactured by Fusion, USA), and output 120 W / Ultraviolet rays were irradiated onto the surface of the coated film using an ultraviolet lamp composed of 4 cm high-pressure mercury lamps. The ultraviolet irradiation distance was 150 mm, and the belt speed was adjusted so that accumulated light amount might be 200 mJ / sq.cm. The coating film thickness of the ultraviolet curable resin layer formed in this way was 3 micrometers. The physical properties of the film produced as described above are measured and shown in Table 1.

68.7 parts by weight of 6-functional aliphatic urethane acrylate oligomer

(Ebecryl 5129, manufactured by UCB Chemicals)

5.0 parts by weight of trimethylolpropane triacrylate

(TMPTA, manufactured by UCB Chemicals)

10.0 parts by weight of pentaerythritol tri / tetra acrylate mixture

(PETA, manufactured by UCB Chemicals)

3.0 parts by weight of methacrylated acidic compound

(Ebecryl 169, manufactured by UCB Chemicals)

5.0 parts by weight of hydroxyethyl acrylate

(HEA, manufactured by UCB Chemicals)

α-hydroxy-ketone 5.0 parts by weight

(Irgacure 184, manufactured by Ciba-geigy)

α-hydroxy-alkyl phenone 3.0 parts by weight

(Darocure 1173, manufactured by Ciba-geigy)

0.3 part by weight of leveling agent

(HS-70, manufactured by UCB Chemicals)

50.0 parts by weight of isopropyl alcohol

<Example 4>

The UV curable composition having the composition shown below was applied onto an untreated polyethylene terephthalate film having a thickness of 100 μm using a 0.5 mm Mayer bar and dried at 50 ° C. for 20 seconds, followed by an ultraviolet irradiation device (F450, manufactured by Fusion, USA), and output 120 W / Ultraviolet rays were irradiated onto the surface of the coated film using an ultraviolet lamp composed of 4 cm high-pressure mercury lamps. The ultraviolet irradiation distance was 150 mm, and the belt speed was adjusted so that accumulated light amount might be 200 mJ / sq.cm. The coating film thickness of the ultraviolet curable resin layer formed in this way was 20 micrometers. The physical properties of the film produced as described above are measured and shown in Table 1.

65.8 parts by weight of a 6 functional aliphatic urethane acrylate oligomer

(Ebecryl 5129, manufactured by UCB Chemicals)

8.0 parts by weight of trimethylolpropane triacrylate

(TMPTA, manufactured by UCB Chemicals)

Pentaerythritol tri / tetra acrylate mixture 8.0 parts by weight

(PETA, manufactured by UCB Chemicals)

5.0 parts by weight of methacrylated acidic compound

(Ebecryl 169, manufactured by UCB Chemicals)

5.0 parts by weight of hydroxyethyl acrylate

(HEA, manufactured by UCB Chemicals)

α-hydroxy-ketone 3.0 parts by weight

(Irgacure 184, manufactured by Ciba-geigy)

α-hydroxy-alkyl phenone 4.0 parts by weight

(Darocure 1173, manufactured by Ciba-geigy)

1.2 parts by weight of leveling agent

(HS-70, manufactured by UCB Chemicals)

50.0 parts by weight of isopropyl alcohol

Comparative Example 1

The UV curable composition having the composition described below was applied onto an untreated polyethylene terephthalate film (Skyrol, SKC Co., Ltd.) having a thickness of 100 μm using a 0.15 mm Meyer Bar, and cured at 160 ° C. for 1 minute to form a 5 μm thick coating film. . The physical properties of the prepared film were measured and shown in Table 1.

Solvent 79.6 wt%

(Methylethylketone)

Thermosetting Acrylic Resin 15% by weight

(Acryloid AT746, Rohm & Haas)

5% by weight of melamine curing agent

(Uformite MM83, product of Rohm Chemical)

0.3% by weight of acid catalyst

(Trifluoro acetic acid, manufactured by Akros)

0.1 wt% of silicone wetting agent

(Disperbyk 110, manufactured by BYK)

Comparative Example 2

Using the ultraviolet curable composition having the composition described below, the physical properties of the film produced in the same manner as in Comparative Example 1 was measured and shown in Table 1.

Solvent 51.9 wt%

(Methylethylketone)

Thermosetting Urethane Resin 45% by weight

(US210, SK Chemicals)

Isocyanate Curing Agent 3% by weight

(Konnate L75, manufactured by Fine Chemical)

0.1 wt% wetting agent

(Disperbyk 103, manufactured by BYK)

Comparative Example 3

The UV curable composition having the composition shown below was coated on an untreated polyethylene terephthalate film (Skyrol, SKC Co., Ltd.) having a thickness of 100 μm using a 0.15 mm Meyer Bar, dried at 50 ° C. for 20 seconds, and then irradiated with an ultraviolet light (product manufactured by Fusion, USA). , F450) and an ultraviolet lamp composed of four high-pressure mercury lamps having an output power of 120 W / cm were irradiated with ultraviolet rays. The ultraviolet irradiation distance was 50 mm, and the belt speed was adjusted so that accumulated light amount might be 200 mJ / sq.cm. The coating film thickness of the ultraviolet curable resin layer formed in this way was 5 micrometers. The physical properties of the film produced as described above are measured and shown in Table 1.

54.5 parts by weight of a 6 functional aliphatic urethane acrylate oligomer

(Ebecryl 5129, manufactured by UCB Chemicals)

20 parts by weight of trimethylolpropane triacrylate

(SR 350, product of Sartomer)

20 parts by weight of n-vinylpyrrolidone

(NVP, ISP company product)

0.5 weight part wetting agent

(HS-300, manufactured by UCB Chemicals)

α-hydroxy-ketone 5.0 parts by weight

(Irgacure 184, manufactured by Ciba-geigy)

50.0 parts by weight of isopropyl alcohol

division Pencil hardness Scratch resistance Chemical resistance Solvent resistance Heat resistance Readability Scavenging Adhesion Example 1 2H Good Good Good More than 240 ℃ Good Good Good Example 2 2H Good Good Good More than 240 ℃ Good Good Good Example 3 2H Good Good Good More than 240 ℃ Good Good Good Example 4 2H Good Good Good More than 240 ℃ Good Good Good Comparative Example 1 F Bad - - - Good - Good Comparative Example 2 F Bad - - - Good - Good Comparative Example 3 H Good - - - Bad - Bad

In Table 1, in the case of Comparative Examples 1-3, the pencil hardness was not sufficient at the F level and the scratch resistance was poor, so it was not meaningful to evaluate other properties, and thus the evaluation of solvent resistance, heat resistance, chemical resistance, and scavenging property was performed. Did not.

As can be seen from the above, the film produced by applying the ultraviolet curable composition according to the present invention to a polyethylene terephthalate film and then irradiating with ultraviolet rays to cure has good scratch resistance, solvent resistance, chemical resistance, heat resistance and the like. In spite of the absence of the primer layer, it is not only excellent in adhesion but also has a high surface hardness of 2H. In particular, it is excellent in the readability of the markers and when used in the hard coat of the film for whiteboard can contribute to productivity improvement because the whiteboard manufacturing process is innovatively simple.

Claims (5)

30 to 90% by weight of UV curable acrylate oligomer, 1 to 30% by weight of UV reactive diluent, 0.1 to 10% by weight of photopolymerization initiator, 0.05 to 20% by weight of leveling agent and remaining amount of solvent As an ultraviolet curable composition comprising: The oligomer is a six functional aliphatic urethane acrylate, the ultraviolet reactive diluent is a monofunctional or polyfunctional acrylate monomer or a mixture thereof, and the leveling agent is an ultraviolet curable non-silicone compound, characterized in that the. The ultraviolet curable composition according to claim 1, wherein the ultraviolet curable non-silicone compound is a modified acrylic resin or an acrylic-styrene copolymer. The ultraviolet curable composition of claim 1, further comprising 1 to 30% by weight of a methacrylated acidic compound as an adhesion promoter. A whiteboard film comprising a coating layer formed by applying the ultraviolet curable composition of any one of claims 1 to 3 on one or both sides of the base film. The film for whiteboard according to claim 4, wherein the UV curable coating layer has a thickness of 1 to 50 µm.