KR100946157B1 - UV Curable Antistatic Coating Composition Including Ionic Liquid - Google Patents

Abstract

The present invention relates to an ultraviolet curable antistatic coating composition and an antistatic sheet and film using the same, wherein the coating is formed by adding a material called an ionic liquid to an acrylic or acrylate based ultraviolet curable resin composition as an antistatic agent. It is an invention for imparting surface hardness and antistatic performance without compromising transparency on the composition and the surface on which the composition is applied. Using the technique of the present invention, it is possible to impart transparency, surface hardness of 2H or more, and antistatic performance to a substrate which is an insulator.

Description

Ultra-violet curable antistatic coating composition with ionic liquids

BACKGROUND OF THE INVENTION Field of the Invention The present invention generally relates to a technique for providing antistatic and surface hardness to films and sheets that are insulators, and to an antistatic film using the same, and more particularly, by adding an ionic liquid to an acrylic or acrylate UV curable resin composition. The present invention relates to a composition which simultaneously provides scratch resistance and antistatic performance to a substrate coated with the composition, and a film having surface hardness and antistatic performance.

In general, the film and sheet used in the display will cause a defect such as scratches or static electricity generated due to friction during the manufacturing and transportation process or lamination process. In order to prevent such defects, it is very important to perform an antistatic treatment on a polarizing film, a diffusion film, a prism sheet, or the like used in a liquid crystal display (LCD), or to improve the surface hardness of the film. In addition, these display films generally use a protective film, which requires a process of peeling off the protective film again, and new problems such as adhesive foreign substances occur due to the transfer of the adhesive layer of the protective film. It has been a problem. Therefore, the invention of the film to which antistatic property was simultaneously provided while providing the surface hardness of 2H or more without reducing transparency is needed.

As a method of improving surface hardness, there exist a method of improving the surface hardness of the base material itself, and the method of apply | coating a high hardness coating composition to the surface. In general, a method of applying a coating composition of high hardness to the surface of the base film is used, and the coating composition used in this method generally uses an ultraviolet curable composition. The UV curable composition mainly uses acrylate oligomers and monomers such as acrylates and methacrylates, and the physical properties depend on the number of reactors or the content ratio of monomers and oligomers. In addition, the physical properties of the composition may be controlled by including epoxy, urethane, and acrylic groups in copolymerized or grafted form.

On the other hand, the antistatic agent of the coating composition is generally used carbon black, quaternary ammonium salts, surfactants, ion conductive polymers and the like. However, these antistatic agents are subject to various restrictions in the use of LCD, and carbon black is difficult to use because of the black color of the product or the occurrence of black foreign substances. Quaternary ammonium salts or surfactants are sometimes used as antistatic agents in coating compositions that require high hardness. (Reference: Korean Patent 10-0184731-0000). However, these components have a problem such as bleeding out to the surface after a certain time and becoming a foreign material or yellowing due to deterioration to become brownish, or the antistatic ability is extinguished, resulting in an electrostatic defect. have. In addition, a so-called IDP (inherently dissipative polymer) may be used as a method of imparting antistatic ability. (Reference: Republic of Korea Patent Publication No. 2002-0091198). IDP is composed of a metal salt such as LiN (CF ₃ SO ₂ ) ₂ and a polymer containing an ester or ester. In general, lithium salts used as metal salts are dissociated into anions such as Li ⁺ cation and N (CF ₃ SO ₂ ) ₂ ^- when mixed with an auxiliary solvent, and after mixing with the base resin, undissociated lithium salts or esters or esters Li ⁺ cation is again N (CF ₃ SO ₂₎ did not bind with the polymer containing ^_2- When combined with anions such as these, it becomes possible to cause crystallization. This is a satisfactory technique for imparting surface hardness and antistatic property of 2H or more to be achieved in the present invention, but for the purpose of forming an antistatic layer on the film surface for the purpose of requiring high transparency, crystallized lithium salts cause scattering in the coating layer. This is an inadequate technique because it can cause whitish phenomena.

Therefore, in the present invention, the invention of the ultraviolet curable antistatic resin composition that can provide permanent antistatic properties while the surface hardness is 2H or more, and the invention of the technology that can provide an antistatic film having a surface hardness of 2H or more using the same.

It is an object of the present invention to provide an ultraviolet curable antistatic resin composition capable of imparting permanent antistatic properties with a surface hardness of 2H or more and an antistatic film having a surface hardness of 2H or more using the same.

In order to achieve the above object, the composition of the present invention is characterized in that it contains an ionic liquid as an antistatic agent in the acrylic or acrylate UV curable resin composition.

The present invention is to prepare an ultraviolet curable antistatic coating resin composition by mixing an antistatic agent consisting of an ionic liquid in the ultraviolet curable resin composition,

The composition of the coating resin composition is largely an antistatic ultraviolet curable resin composition containing an ultraviolet curable resin such as an ionic liquid, an acrylate oligomer or a monomer as an active ingredient. Photoinitiators or other additives can be mixed and used here. After coating the antistatic composition thus prepared on the base film, the surface resistance is sufficient to impart antistatic properties to the surface of the polymer film, which is an electrical insulator at 10 ⁸ -10 ¹² ohms / area.

First, the antistatic agent uses an ionic liquid. Ionic liquids that can be used in the present invention include cations, bromide, and hexafluorophosphate composed of alkylimidazolium, alkylphosphonium, N-alkylpyridinium, N, N'-dialkylimidazolium or derivatives thereof, and the like. , Hexafluoroantimonite, tetrafluoroborate, trifluoromethane sulphate, methane sulfate, tosylate, chloride or an anion which is a derivative thereof, and is substituted with pyridinium as shown in Chemical Formula 1 below. ,

Or a form in which imidazolium is substituted as shown in Formula 2,

Or a form in which pyrrolidinium is substituted as in Chemical Formula 3,

 Or a form of an amine substituted with an aliphatic group as shown in Formula 4,

Or the like. In more detail, in the case of R ₁ , R _{2 ,} R _{3, and} R ₄ in Formulas 1,2,3,4, alkyl groups such as ethyl, methyl, hexyl, octyl, or benzyl, phenylpropyl, etc. may be substituted. , X ^- in the case, bromide, a anion such as hexamethylene Floro phosphate, hexafluoro antimonate Floro nitro, tetra fluoroborate flow, with a triple methane sulfate, methane sulfate, tosylate, chloride may be substituted. It can be used as a single type or can be used by mixing two or more kinds. In addition, the introduction of a high molecular weight alkyl chain or a polymer chain with good compatibility with the base resin to R _{1 ,} R _{2 ,} R _{3 , and} R ₄ slows deterioration or bleed-out that may be a problem as low molecular weight organic material. It is possible. The ionic liquid is a material that exhibits ion conduction by dissociating ions. If the content of the ionic liquid is too small, the antistatic performance is lowered. If the ionic liquid is too large, the increase in the antistatic performance is slowed and the thermal stability of the ionic liquid is degraded. In addition to the mechanical properties of the coating film may be impaired, it is preferable to use an ionic liquid content of 0.01 to 20 parts by weight based on 100 parts by weight of the final antistatic coating composition. In addition, in order to maintain the transparency of the base resin, the compatibility with the UV-curable resin used as the base resin is good, does not impair the appearance, the difference in refractive index with the base resin is less than 0.05 is less than the ionic that does not inhibit the light transmittance The choice of liquid is important. If the difference in refractive index is more than 0.05, diffuse reflection occurs inside the coating layer, thereby decreasing the transmittance of light.

In the use of the ionic liquid as an antistatic agent, other additional solvents may be used as necessary to improve dispersibility. The solvent may be mostly so long as it can dissolve the ultraviolet curable resin while dissolving the ionic liquid. . As such a solvent, ketone solvents such as toluene and methyl ether ketone, acetate solvents, lower alcohol solvents such as methyl alcohol, ethyl alcohol and isopropyl alcohol, aldehyde solvents such as dimethyl formaldehyde, diethyl ether and dipropyl ether Ether solvents such as alcohol ethers, amide solvents such as en-methyl-2-pyridyridone, sulfoxide solvents such as dimethyl sulfoxide, amine solvents such as alkyl amines, cyclic amines, aromatic amines, and the like. Any one or more of the solvents may be selected and used.

On the other hand, the UV-curable resin of the present invention has good adhesion to the substrate of the coating target, and uses an acrylate resin among the resins with good dispersibility and compatibility with the antistatic agent prepared, urethane group, ester group, ether It is more effective to use an acrylate resin containing any one or more of a group, an acryl group, an epoxy group, an amide group or a component such as a modified amide group and a carboxyl group modified therefrom. Such UV curable resins include oligomers or monomers having good adhesion to the substrate to be coated and compatibility with the antistatic agent, and have an acrylate or methacrylate UV curable oligomer having 1-15 functional groups or 1-6 functional groups. The acrylate or methacrylate monomer which has the thing can be used individually or in mixture of 2 or more types.

In addition, additives such as an antifoaming agent, a leveling agent, a dispersing agent, and an ultraviolet absorber may be additionally added in an amount of 0.01-5 parts by weight based on 100 parts by weight of the total coating composition as necessary to reinforce the surface and mechanical properties of the coating composition and improve coating properties. It may be. At this time, if the additive content is less than 0.01 parts by weight, the effect of addition is small, and if it is 5 parts by weight or more, these components may act as impurities and may damage the physical properties of the coating layer.

On the other hand, in order to impart light diffusing performance to a display film (for example, a light diffusing film), the coating composition of the present invention, based on 100 parts by weight of the coating composition, such as polymethyl methacrylate beads, crosslinked polystyrene beads Polymer beads, or oxide particles such as tin oxide, zinc oxide, titanium oxide, silica, or other fillers may be further mixed in an amount of 0.01-100 parts by weight. Although the content ratio varies depending on the type of beads or fillers used, it may be difficult to achieve the purpose of using each filler or bead when the content is less than the minimum content. If the content is more than the maximum content, the light transmittance or the excessive content is used. Due to this may lower the physical properties of the coated surface it is preferable to use within the above range.

Photoinitiator should be mixed with the ultraviolet curable resin composition of this invention. The photoinitiator has a short wavelength and a long wavelength photoinitiator can be used alone or a mixture of these two photoinitiators. In order to achieve the object of the present invention, it is not limited to a special photoinitiator, but an appropriate photoinitiator may be selected and used according to the wavelength type of the ultraviolet lamp of the ultraviolet curing machine.

As the object to which the coating composition according to the present invention can be coated, the base polymer film (or sheet) or the injection molded product may use any polymer that requires surface hardness and antistatic property. Polymers used for display applications include ester polymer films such as polyethylene terephthalate, styrene polymer films such as polystyrene, olefin polymer films such as cyclic olefin polymers, carbonate polymer films such as polycarbonate, and polyimide. It may be applied to a de-based polymer film, a sulfone-based polymer film such as polyether sulfone, a cellulose-based polymer film such as triacetyl cellulose, an acrylic polymer film such as polymethyl methacrylate, or any other polymer film or sheet. The present invention is also applicable to polymer films having only one component or complexed or mixed with two or more components.

In addition, when the composition of the present invention is applied to an optical film or a sheet, in consideration of the refractive index of the base film and the polymer constituting the sheet, a UV-curable resin having a lower refractive index than the base film is used, UV curable resins having a higher refractive index than the base film are used on the opposite side, or on both sides, to obtain additional optical films and sheets having improved light transmittance. For example, if the base film is a polyester film having a refractive index of 1.65, and wants to improve the hardness of the light-receiving surface, use an ultraviolet curable resin having a refractive index of less than 1.65, and want to improve the hardness of the light-reversed surface. In the case of using an ultraviolet curable resin having a refractive index greater than 1.65, it is possible to produce a film having improved hardness while improving light transmittance.

As one of the methods for maximizing the effect in providing the antistatic property, which is the object of the present invention, an antistatic layer containing a conductive polymer as an active ingredient is first formed on the base film surface, and then the antistatic layer for hard coating of the present invention is formed thereon. Formation is advantageous because the antistatic effect can be maximized. At this time, the antistatic layer formed of the conductive polymer as an active ingredient may be used in various conventional methods. For example, a poly (3,4-ethylenedioxythiophene) dispersion solution as a well-known technique (Reference: Republic of Korea Patent 422321). 1 gram, 0.3 grams of water-soluble urethane binders, 0.03 grams of urethane curing agent, 0.3 grams of ethyl acetate, 0.3 grams of NMP, 5.5 grams of isopropyl alcohol, 3 grams of water, 0.005 grams of wetting agent, and dried with 80-degree hot air A method of forming a 0.1 micron thick antistatic layer can be used.

Depending on the type of polymer, the UV curable resin composition of the present invention may have poor adhesion to the surface of the polymer. In this case, when the surface of the polymer is modified to have 35 dynes / area or more by primer treatment or corona treatment with an adhesion promoter, It is effective because it can enhance the adhesion on the surface.

The composition of the UV curable coating composition is not particularly limited as long as it is a method commonly known in the art, and depending on the material and shape of the base film, an air knife method, gravure method, reverse roll method, reverse gravure method, spray method, slot Any coating method can be used as long as it is not limited to a special method such as a die coating method, a blade method, an impregnation method, or a spray coating method and is commonly used. In addition, a composite coating method in which two or more of these methods are applied may be used.

Using the technique of the present invention, the base film and the sheet have a high hardness and high light transmittance, and have a desired antistatic performance with a surface resistance of about 10 ⁸ -10 ¹² ohms / area, and a low friction voltage and Short decay time can be given.

Hereinafter, the present invention will be described in detail with reference to the following examples. However, the following examples are only examples for describing the present invention and do not limit the scope of the present invention.

Property measurement

Surface resistance, friction voltage, decay time, surface hardness, adhesion, and optical properties were measured to demonstrate the effect of the present invention. Each specimen was made in size of 10 cm X 10 cm, and the measurement method of each item is as follows.

Surface resistance: After applying the coating composition to the base film using ProRS PRS-801 of the United States and UV cured to prepare a specimen, the surface resistance was measured according to the method of ESD STM 11.11.

Friction voltage: After coating composition on base film surface, UV cured to make specimen, and after wearing nitrile gloves, rub it ten times strongly, and using FMX-003 manufactured by Japan Simco, ESD Measurement was made according to the STM 11.2 method.

Decay time: After coating the coating composition on the base film surface and UV cured to prepare a specimen, it was measured according to the FTMS 101C method using CPM 288 of Monroe Electronics.

Surface Hardness: After coating the coating composition on the surface of the base film and UV cured to prepare a specimen, the pencil hardness was measured using the method of ASTM D 3363.

Adhesion: After the coating composition was applied to the surface of the base film, UV cured to prepare a specimen, and measured using the method of ASTM D 3359.

Optical properties: After coating the coating composition on the surface of the base film and UV cured to prepare a specimen, the optical properties were measured using the method of ASTM D 1003.

Comparative Example 1

After coating the coating composition which mixed 1 gram of photoinitiator to 100 grams of UV-curable urethane acryl-type oligomer dissolved in 50 weight percent in methyl ethyl ketone, it was coated on a 100 micron polyester film using a bar coater and dried at 80 degrees for 2 minutes, A coating film was formed by irradiating 300 milliliters of light. At this time the coating thickness of the composition was 3 microns.

Table 1 shows the physical properties of the sheet produced by the above technique.

<Example 1>

A coating composition containing 100 grams of UV-curable urethane acrylic oligomer dissolved in methyl ethyl ketone at 50% by weight, 0.5 gram of ionic liquid and 1 gram of photoinitiator was coated on a 100 micron polyester film using a bar coater at 80 degrees. After drying for 2 minutes, a coating film was formed by irradiating 300 milliliters of light. At this time the coating thickness of the composition was 3 microns.

Table 1 shows the physical properties of the coating film prepared by the above technique.

<Example 2>

Example 2 is the same as in Example 1 except that the amount of the ionic liquid to 1 gram when mixing the coating composition of Example 1.

Table 1 shows the physical properties of the coating film prepared by the above technique.

<Example 3>

Example 3 is the same as in Example 1 except that the content of the ionic liquid to 2.5 grams when mixing the coating composition of Example 1.

Table 1 shows the physical properties of the coating film prepared by the above technique.

<Example 4>

Example 4 is a poly (3,4-ethylenedioxythiophene) dispersion solution 1 as an antistatic composition containing a conductive polymer as a main component on a film surface before application of the coating composition of Example 2 (reference: Republic of Korea Patent No. 422321). Grams, 0.3 grams of water-soluble urethane acrylic binder, 0.03 grams of urethane curing agent, 0.3 grams of ethyl acetate, 0.3 grams of NMP, 5.5 grams of isopropyl alcohol, 3 grams of water, 0.005 grams of a wetting agent to prepare an antistatic composition and coating It was dried with hot air at 80 degrees to form a 0.2 micron thick antistatic layer on the surface. It is the same as that of Example 1 except using the coating composition of Example 2 to form an ultraviolet cured antistatic layer on the surface.

Table 1 shows the physical properties of the coating film prepared by the above technique.

Comparative Example 1 Example 1 Example 2 Example 3 Example 4 Surface Resistance (Ω / sq) > 1E13 1E11 5E11 1E11 7E10 Friction Voltage (kV) 18.6 6.0 1.9 0.7 0.3 Decay time (s) > 300 180.4 114.2 30.1 10.8 Surface hardness 2H 2H 2H 2H 2H Adhesion 5B 5B 5B 5B 5B Total light transmittance (%) 92.1 91.5 91.7 91.6 89.2 Haze (%) 1.3 1.5 1.0 0.9 1.2

(Effects according to the content of ionic liquids)

Example 5

Example 6 is the same as Example 1 except that the coating thickness is 5 microns.

Table 2 shows the physical properties of the coating film prepared by the above technique.

<Example 6>

Example 7 is the same as Example 1 except that the coating thickness is 10 microns.

Table 2 shows the physical properties of the coating film prepared by the above technique.

Example 1 Example # 5 Example 6 Coating film thickness (μm) 3 5 10 Surface hardness 2H 3H 4H

(Change of Surface Hardness According to Thickness of Coating Film)

Claims (14)

In the ultraviolet curable antistatic coating composition, The composition comprises an ionic liquid as an antistatic agent in an acrylic or acrylate UV curable resin composition, The ionic liquid Cations consisting of alkylimidazolium, alkylphosphonium, N-alkylpyridinium, N, N'-dialkylimidazolium or derivatives thereof, and Anions including bromide, hexafluorophosphate, hexafluoroantimonite, tetrafluoroborate, trifluoromethane sulphate, methanesulfate, tosylate, chlorides or anions thereof, It consists of, when the ultraviolet curable resin composition 100 parts by weight of 0.01-20 parts by weight is mixed, and The ultraviolet curable resin is one or a mixture of two or more acrylates or methacrylate monomers having 1-15 functional groups or an acrylate or methacrylate monomer having 1-6 functional groups, UV curable antistatic coating composition, characterized in that. delete delete The method of claim 1, wherein as the solvent of the ionic liquid, Toluene, ketone solvent containing methyl ether ketone, acetate solvent, methyl alcohol, ethyl alcohol, alcohol solvent containing isopropyl alcohol, aldehyde solvent containing dimethyl formaldehyde, diethyl ether, dipropyl ether, alcohol Ether solvent including ether, amide solvent including en-methyl-2-pyridyridone, sulfoxide solvent including dimethyl sulfoxide, alkyl amine, cyclic amine, amine including aromatic amine A solvent comprising any one or more of solvents, UV curable antistatic coating composition, characterized in that it further comprises. delete According to claim 1, In order to reinforce the surface or mechanical properties of the coating composition and to improve the coating properties, an additive including any one or more of an antifoaming agent, a leveling agent, a dispersant, and an ultraviolet absorber 0.01 to 100 parts by weight of the total coating composition UV curable antistatic coating composition, characterized in that it further comprises -5 parts by weight. According to claim 1, wherein 100 parts by weight of the coating composition Polymeric beads, including polymethylmethacrylate beads or crosslinked polystyrene beads, or Oxide particles including tin oxide, zinc oxide, titanium oxide, silica, UV-curable antistatic coating composition, characterized in that it further comprises 0.01-100 parts by weight. delete delete delete UV curable antistatic coating composition comprising an ionic liquid as an antistatic agent in an acrylic or acrylate UV curable resin composition, or The ultraviolet curable antistatic coating composition of any one of claims 1, 4, 6, and 7, As a coating film coated using When the film is an optical film or sheet, an ultraviolet curable resin having a lower refractive index than that of the base film is used on the surface where light enters, or an ultraviolet curable type having a higher refractive index than the base film on the opposite side where light enters, depending on the refractive index of the base film or sheet. A coating film, characterized in that each resin is used, or both sides. The method of claim 11, wherein the coating is coated using an air knife method, gravure method, reverse roll method, reverse gravure method, spray method, slot die coating method, blade method, impregnation method or spray coating method Coated film. An injection molding coated using the ultraviolet curable antistatic coating composition of any one of claims 1, 4, 6 and 7. An antistatic layer containing a conductive polymer as an active ingredient is first formed on the surface of the base film, and then charged thereon using the ultraviolet curable antistatic coating composition of any one of claims 1, 4, 6, and 7. Coating film which formed prevention layer.