KR100662179B1 - Organic-inorganic hybrid hard coating composition and coating method of a substrate using the same - Google Patents

Abstract

The present invention is an organic-inorganic hybrid comprising inorganic nano colloidal silica sol, polyethylene dioxythiophene / polysulfonate (PEDT / PSS) conductive polymer, photocurable acrylic monomer or oligomer, organic solvent, photoinitiator and light stabilizer. The present invention relates to a hard coating composition and a coating method of a substrate using the same. According to the hard coating composition of the present invention, an organic-inorganic hybrid sol may be used to prepare a hard coating sheet having excellent light transmittance and excellent antistatic property and scratch resistance. It can be used in various home appliances, large display panel protection, and the inside and outside panels of the mobile phone.

Hard coating composition, organic / inorganic, hybrid sol, conductive polymer, photoinitiator, light stabilizer,

Description

ORGANIC-INORGANIC HYBRID HARD COATING COMPOSITION AND COATING METHOD OF A SUBSTRATE USING THE SAME}             

1 is a schematic cross-sectional view of a hard coat sheet according to the prior art,

2 is a schematic cross-sectional view of a hard coat sheet according to the present invention.

* Description of the symbols for the main parts of the drawings *

11, 21: plastic substrate 12, 22: acrylic monomer or oligomer

13: metal oxide 23: nano colloidal silica sol

24: electrically conductive polymer

The present invention relates to an organic-inorganic hybrid hard coating composition and a coating method of a substrate using the same, and more particularly, to an organic-inorganic hybrid sol, which includes a hard coating sheet having excellent light transmittance and excellent antistatic property and scratch resistance. It relates to a hard coating composition and a coating method of the substrate using the same can be prepared.

Generally, photocurable plastic hard coatings are widely used in building materials, automotive exterior parts, paper, wood, furniture, soundproof walls, optical materials, cosmetic containers, and displays. In particular, a hard coating sheet (film) is attached to a surface of various home appliances, a large image display device, a window of a mobile phone, and the like to protect the surface and prevent scratches.

As an example of a conventional photocurable hard coating solution, Japanese Patent Laid-Open No. 5-214044 discloses a polyfunctional monomer having three or more (meth) acryloyl groups, polyethylene glycol methacrylate, polyoxyethylene glycol acrylate, polyethylene glycol methacrylate. The hard coating composition containing monofunctional or bifunctional monomers, such as a polypropylene glycol methacrylate, is disclosed.

On the other hand, Japanese Patent Laid-Open No. 5-214045 discloses a polyfunctional monomer having three or more (meth) acryloyl groups, polyethylene glycol methacrylate, polyethylene glycol methacrylate, polyethylene trimethacrylate, and polyoxyethylene glycol tetramethacryl. Disclosed is a hard coating composition comprising a monofunctional or bifunctional monomer such as a rate.

Japanese Patent Laid-Open No. 5-186534 is a phosphate ester having acryloyl group or methacryloyl group; An organic compound having at least one ultraviolet curable functional group and at least one tertiary amine group in a molecule; And an ultraviolet curable coating material having an antistatic performance and hardness containing an organic compound having at least two active ethylene groups in a molecule.

However, the conventional techniques up to now have been mostly transparent hard coating liquids for the purpose of scratch resistance only, and the products without the antistatic property were the mainstream. In addition, even in the case of antistatic property, the ion conductive material is added in most cases, the conductivity is often degraded over time, and the antistatic function is often lowered. Therefore, in order to provide antistatic performance and electromagnetic wave blocking performance to the hard coating sheet, an antistatic hard coating agent using a conductive oxide of a metal oxide type such as ATO (antimon tin oxide) or ITO (indium tin oxide) is developed as a plastic hard coating agent. It became. Figure 1 schematically shows a cross section of a hard coat sheet having such a conventional antistatic film formed on a plastic substrate. As shown in FIG. 1, a hard coating layer is formed on the plastic substrate 11, wherein the hard coating layer is a metal oxide 13 dispersed in an acrylic monomer or oligomer 12. Such coatings have the advantages of excellent antistatic persistence and generally high transparency by free electron charge transfer. However, when the hard coating agent is coated on the transparent plastic, the transmittance is low, about 80% to 85%, and the color of the blue tone impairs the appearance of the transparent plastic and the storage stability due to the aggregation phenomenon of the metal oxide particles over time. In addition, there is a problem that it is not suitable for commercial applications because the sharp drop and the price of the coating liquid itself is very expensive to increase the cost of the coated plastic product.

In addition, the conventional hard coating layer has a weak surface pencil hardness of about 3 ~ 4H has been tried a lot of efforts to improve the hardness of the hard coating layer. In order to increase the hardness of the hard coating layer, a coating composition comprising a resin-forming component as a polyfunctional acrylic ester monomer and containing a powdered inorganic filler and a polymerization initiator is disclosed in Japanese Patent No. 1815116. Further, a photopolymerizable composition comprising an inorganic filler made of surface treated silica or alumina is disclosed in Japanese Patent No. 1416240. However, these methods have an effect of slightly increasing the surface hardness of the hard coat sheet, but this alone does not sufficiently meet the surface hardness performance of the recently required hard coating film.

Therefore, the conventional hard coating composition and the hard coating sheet using the same have high durability and solvent resistance, light transmittance, antistatic properties, etc., as compared to the high performance and optical characteristics required for miniaturization and high definition trends such as display devices and mobile phone terminals. There is a limit not to reach. Therefore, there is an urgent need to develop a hard coating composition capable of producing a high-performance hard coating sheet having not only excellent scratch resistance but also antistatic performance, sufficient hardness, and light transmittance.

Accordingly, the present invention is to overcome the problems of the prior art described above, to provide an environmentally friendly and low-cost hard coating composition.

Another object of the present invention is to provide a hard coating composition having high light transmittance, antistatic property, scratch resistance, and abrasion resistance and a coating method of a substrate using the same.

One aspect of the present invention for achieving the above object is an inorganic nano colloidal silica sol, polyethylene dioxythiophene / polysulfonate (PEDT / PSS) conductive polymer, photocurable acrylic monomer or oligomer, organic solvent, photoinitiator and light stabilizer It relates to an organic-inorganic hybrid hard coating composition comprising a.

Another aspect of the present invention relates to a method of coating a plastic substrate and a hard coating sheet using the organic-inorganic hybrid hard coating composition of the present invention.

Another aspect of the present invention relates to a hard coat sheet manufactured using the organic-inorganic hybrid hard coating composition of the present invention and an image display device including the same.

Hereinafter, with reference to the accompanying drawings will be described in more detail with respect to the present invention.

The organic-inorganic hybrid hard coating composition of the present invention is a polyethylenedioxythiophene / polysulfonate (PEDT / PSS) conductive polymer as a low-cost conductive material in order to improve the problems such as price problems and lowered transmittances of conventional metal oxides. And a nano colloidal silica sol as a material to impart a high transmittance. The hard coating composition according to the present invention is to improve the antistatic and scratch characteristics on the outer surface of the polymethyl methacrylate (PMMA) sheet used in the window of the electronics, mobile phone window and the like.

Specifically, the hard coating composition of the present invention includes inorganic nano colloidal silica sol, polyethylene dioxythiophene / polysulfonate (PEDT / PSS) conductive polymer, photocurable acrylic monomer or oligomer, organic solvent, photoinitiator and light stabilizer. The preferred composition ratio of each component is as follows:

Inorganic nano colloidal silica sol: 1-10% by weight;

Polyethylene dioxythiophene / polysulfonate conductive polymer aqueous solution: 5-20 wt%;

Photocurable acrylic monomer or oligomer: 10 to 50% by weight;

Organic solvent 30 to 70% by weight;

1-5 wt% photoinitiator; And

Light stabilizer 0.05 ~ 1.0 wt%

The hard coating composition of the present invention comprises a nano-sized colloidal silica sol to improve pencil hardness, wear resistance and transmittance of the hard coating sheet. The nano colloidal silica sol collects the incident light after scattering to form a coating layer so that the transmittance of the coating layer is improved. In the present invention, the inorganic nano colloidal silica sol is used for improving the transmittance of the coating film and increasing the hardness of the coating film. When the content is less than 1% by weight, the effect is insignificant. This may cause haze and antistatic performance. The nanocolloidal silica sol used in the present invention has an average particle diameter of 3-50 nm, preferably 5-20 nm, and a silica concentration. It is preferred that it is 10-50% by weight. For example, an aqueous product of Nalco ^™ 1030, 1140, 2326, and 2327, which is a colloidal silica dioxide containing 30 to 40% of SiO ₂ solids, may be used. In the hard coating composition of the present invention, the content of the inorganic nano colloidal silica sol is preferably 1 to 10% by weight.

Polyethylene dioxythiophene / polysulfonate (PEDT / PSS) conductive polymers used in the present invention are excellent in thermal stability, UV stability, processability and low cost compared to other commercially available polymers. Since the conductive polymer is water-based, it is excellent in compatibility with the alcohol solvent and is not a particle system, and thus is suitable as a transparent film or a transparent hard coating liquid because it does not lower the transmittance of the coating film. The content of the conductive polymer in the hard coating composition of the present invention is preferably 5 to 20% by weight. If the content of the conductive polymer is less than 5% by weight, the conductivity is lowered and the antistatic function is not sufficiently exhibited. If the content of the conductive polymer is more than 20% by weight, the antistatic property is excellent, but the curing speed is delayed, resulting in poor processability and weakness of the coating film May occur. The solid content concentration of the conductive polymer is preferably 0.1 to 5% by weight.

As the photocurable resin used in the composition of the present invention, one or two or more resins selected from the group consisting of an acrylic monofunctional monomer, a bifunctional monomer, a trifunctional or higher polyfunctional monomer or an oligomer can be mixed and used. Since most photocurable acrylic oligomers have high viscosity, they are appropriately lowered with an acrylate monomer, which is a reactive diluent, to be used in combination according to product characteristics and uses. For example, examples of acrylic monofunctional monomers include, but are not necessarily limited to, butyl acrylate, allyl methacrylate, 2-methoxyethyl acrylate, 2-hydroxyethyl methacrylate. Examples of acrylic difunctional monomers include 1,6-hexanediol diacrylate (HDDA), 1,3-butylene glycol dimethacrylate (BGMDA), tripropylene glycol diacrylate (TPGDA), and the like. Examples of trifunctional or more than trifunctional monomers include, but are not limited to, trimethylolpropane triacrylate (TMPTA), pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA), and the like. .

In the present invention, it is preferable to use a hybrid acrylic monomer in which one functional group or more than three functional groups are appropriately combined, and the acrylic monomer having four or more functional groups can shorten the curing time and obtain a high pencil hardness, but the impact resistance, wear resistance, flexibility, etc. Degrading problems may occur. In addition, the acrylic monomer having a trifunctional group or less greatly contributes to improving the flexibility of the coating film, but may have problems in improving the pencil hardness. In the present invention, the content of the photocurable acrylic monomer or oligomer is preferably in the range of 10 to 50% by weight. When the content is less than 10% by weight, it is difficult to maintain the thickness of the appropriate hard coating film and the hardness of the coating film may be low. When the content is more than 50% by weight, the surface conductivity may be low, which may cause the antistatic performance.

In the present invention, the organic solvent may dissolve the photocurable resin and control the flowability of the coating solution, methanol, ethanol, isopropanol, normal-propanol, butanol, isobutanol, ethyl cellosolve, methyl cellosolve, butyl cello Solvent, butyl acetate, diacetone alcohol, methyl ethyl ketone, propylene glycol isopropyl alcohol, ethylene glycol isopropyl alcohol may be used one kind or a mixture of two or more kinds. The solvent is most preferably used in a mixture of less than 3 to 4 kinds in consideration of coating properties, appearance of the product, and production yield.

Photoinitiator in the present invention 1-hydroxy-cyclohexyl-phenylkenone (Irgacure-184),

α, α-dimethoxy-α-hydroxy acetophenone (Darocure 1173), blend of 1-hydroxy-cyclohexyl-phenyl ketone benzophenone, 2-hydroxy-2-methyl-1-phenyl propane can be used However, it is not necessarily limited to these.

In the hard coating composition of the present invention, a trace amount of light stabilizer is added in an amount of about 0.02 to 1.0% by weight in order to prevent light stability and long-term change of the coated film. Examples of such light stabilizers include bis- (1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl (Ttinubin 123) .The viscosity of the hard coating composition of the present invention is 25 ° C. Is preferably in the range of 5 to 100 cps.

The hard coating composition of the present invention may further include other additives, such as a leveling agent and an ultraviolet absorbent, as necessary in addition to the above-described components.

Hereinafter, a method for hard coating the surface of a transparent plastic substrate using the coating liquid composition of the present invention. In the present invention, the substrate is polymethyl methacrylate (PMMA), polycarbonate (PC), methyl methacrylate-styrene

Copolymer (MS) sheets and the like may be used, but are not necessarily limited thereto.

Such substrates are used in applications such as 0.8 mm to 2.0 mm thick. In the present invention, as a coating method, the substrate is sufficiently washed first, preheated with an ultraviolet irradiator to remove remaining oil and foreign substances, and the amount of the organic solvent is adjusted so that the viscosity of the hard coating composition is in the range of 5 to 100 cps at 25 ° C. Adjust and coat. At this time, as a coating method, a dip coating, a flow coating, a spray coating, a spray coating, a roll coating, a gravure coating, and a suitable method may be selected and used. Subsequently, after the coating, the organic solvent in the coating solution is completely dried by drying or IR heating at a temperature in the range of 40 to 80 ° C. for 1 to 20 minutes, and then irradiated with UV light at a light amount of 300 to 800 mJ / cm 2 to obtain a completely cured coating film. In this case, a lamp suitable for the wavelength range of the material used among the mercury lamp or the metal halide lamp is used.

An example of the hard coat sheet manufactured by the above method is shown in FIG. As shown in Figure 2, the hard coating sheet according to an embodiment of the present invention is a hard coating layer is formed on the plastic substrate 21, the hard coating layer is an acrylic monomer or oligomer 22, nano colloidal silica sol (23) , And an organic conductive polymer 24. The hard coating sheet manufactured by the hard coating composition of the present invention is a high functional sheet capable of preventing reflection and glare because of excellent scratch resistance, high transmittance, and antistatic property, such as a liquid crystal display (LCD) and a plasma display panel ( It can be applied to the protection panel of various image display devices such as PDP), electroluminescent display (ELD), electroluminescent display, and the like, inside and outside panels of a mobile phone terminal.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are only for explaining the present invention and are not intended to limit the claims of the present invention.

Example 1

In a plastic beaker capable of blocking light, an aqueous solution of polyethylene dioxythiophene / polysulfonate (PEDT / PSS) conductive polymer is first added and vigorously stirred, followed by the addition of solvents such as methanol, isopropanol, normal-propanol and methylcellosolve. Stir at about 2 hours. Pentaerythritol triacrylate (PETA; manufactured by Satomer) and dipentaerythritol hexaacrylate (DPHA: manufactured by Satomer) were added to the prepared intermediate solution, and the mixture was stirred for about 2 hours. Subsequently, the nano colloidal silica sol was diluted with the solvent described above using ultrasonic dispersion or milling, and then added to the intermediate solution to prepare a coating solution. Finally, after adding the photoinitiator (Irgacure 184) and the light stabilizer (Tinubin), the mixture was stirred and uniformly dispersed for about 1 hour, and then filtered using a 10 micron filter to remove foreign substances from the solution to obtain a final hard coating composition. It was.

Finally, the coating solution obtained was flow coated on a 1.0 mm sheet of polymethyl methacrylate (PMMA), dried at about 60 ° C. to 75 ° C. for about 5 minutes using a high pressure mercury lamp, and then the organic solvent in the coating solution. After completely removed, ultraviolet light of about 600 mJ / cm 3 light was irradiated to obtain a hard coat sheet. Then, the physical properties of each sheet obtained were evaluated and the results are shown in Table 2 below.

Physical properties of the hard coat sheet in the present invention was evaluated by the following method.

[Property evaluation method]

Surface resistance; Surface resistance per unit area was measured using a surface resistor (Mitsubishi Chemical, Hiresta).

* Light transmittance; Evaluation was performed using a UV-Visible Spectrometer.

Pencil hardness; It evaluated by ASTM D3502 (pencil hardness tester, toyoseki) method.

Scratch resistance; Steel wool # 000, 500 g rod 30 times scrubbing was evaluated.

Examples 2-6 and Comparative Example 1

Except that the coating composition was prepared by changing the composition of the hard coating composition as shown in Table 1 below, a hard coating sheet was prepared in the same manner as in Example 1, and the physical properties thereof were shown in Table 2 below. In Table 1, the unit of the content of each component is weight percent.

Comparative Example 2

As the conductor, ATO (antimontinoxide) sol, which is a metal oxide, was used, and pentaerythritol triacrylate (PETA), 1,6-hexanediol diacrylate (HDDA), and 2-hydride were used as photocurable acrylic or urethane acrylic monomers and oligomers. Oxyethyl

Metal methacrylate (HEME), 2-hydroxy propyl metal acrylate (HPMA) were used, Irgcure 184 was used as a photoinitiator, isopropyl alcohol, ethyl acetate, methyl ylketone, toluene, xylene as an organic solvent. Using a commercially available antistatic hard coating agent made of a coating in the same manner as in Example 1 to prepare a hard coating sheet and to evaluate the physical properties are shown in Table 2 below.

 division  ingredient  Example  Comparative example One 2 3 4 5 6 7 One 2 Conductive polymer PEDT (1.3%, aq) 7 9 11 13 15 12 12 5 Commercial antistatic coating liquid menstruum MeOH 5 7 9 10 12 10 10 3 IPA 10 6 2.9 3.9 2.9 2.9 2.9 5 NPA 11.9 6.9 4 2 3 5 5 6.9 MC 40 40 37 30 30 33 34 40 Photocurable acrylic monomer or oligomer TMPTA 5 PETA 12 12 12 12 12 12 6 12 DPHA 10 15 20 25 20 20 20 20 Photoinitiator Irgacure 184 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 Light stabilizer Tinubin 123 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1  Inorganic Nano Colloidal Silica Sol Nalco 1030 1.0 - - - - - - - Nalco 1140 - 1.0 - - 2.0 - - - Nalco 2326 - - 1.0 - - 2.0 2.0 - Nalco 2327 - - - 1.0 - - - -

* PEDT: Polyethylene dioxythiophene / polysulfonate (PEDT / PSS, Germany BAYER company)

* PETA: Pentaerythritol triacrylate (Satomer)

* DPHA: dipentaerythritol hexaacrylate (Satomer)

* TMPTA: Trimethylpropane triacrylate (Satomer)

IPA; Isopropanol / MC; Methylcellosolve / NPA; n-propanol

Irgacure 184; 1-hydroxycyclohexyl phenyl ketone (Shibagaiki Co., Ltd.),

Tinubin 327; Bis- (1-octyloxy-2,2,6,6-tetramethyl-4-piperidinyl (Ciba-Geigy Co., Ltd.)

* Nalco 1030, Nalco 2326, Nalco 1140: colloidal silica dioxide

(Ondeo Nalcosa)

division Hard coating sheet properties Exterior Surface Resistance (ohm / sq.) Transmittance (%) Pencil Hardness (H) Scratch resistance Standard specification Less than 1.0E10 over 90 4H or more 30 times or more Great Example 1 3.0E10 91.0 5H Good Great Example 2 8.0E09 91.2 5H Good Great Example 3 3.0E09 91.4 5H Good Great Example 4 5.0E08 91.6 6H Good Great Example 5 4.0E07 92.2 4H Good Great Example 6 1.0E09 91.7 5H Good Great Example 7 4.0E08 92.4 6H Good Great Comparative Example 1 8.0E10 90.5 4H Bad Great Comparative Example 2 1.0E10 91.0 4 ~ 5H usually Good

The hard coating composition according to the present invention has the advantage that the hard coating sheet produced by the composition of the present invention using an organic-inorganic hybrid sol has excellent light transmittance and excellent antistatic property and scratch resistance. In addition, the hard coating composition of the present invention has the advantages of excellent dispersion stability and storage stability compared to the conventional inorganic solution, and does not require freezing storage, so it is easy to transport, adopting a water-soluble polymer, environmentally friendly and low cost, commercialization Has a suitable advantage.

Claims (13)

Inorganic nano colloidal silica sol: 1-10% by weight; Polyethylenedioxythiophene / polysulfonate conductive polymer aqueous solution: 5-20 wt%; Photocurable acrylic monomer or oligomer: 10 to 50% by weight; Organic solvent: 30 ~ 70 wt%: 1-5 wt% photoinitiator; And Hard coating composition comprising a light stabilizer 0.05 ~ 1% by weight. delete delete delete delete delete The hard coating composition of claim 1, wherein the solid content concentration of the conductive polymer is 0.1 to 5 wt%. The method according to claim 1, wherein the photocurable acrylic monomer is composed of a functional monomer, a bifunctional monomer, a trifunctional or higher polyfunctional monomer or a mixture thereof, butyl acrylate, allyl methacrylate, 2-methoxyethyl acrylate, 2-hydroxyethyl methacrylate, 1,6-hexanediol diacrylate (HDDA), 1,3-butylene glycol dimethacrylate (BGMDA), tripropylene glycol diacrylate (TPGDA), trimethylolpropane Hard coating composition, characterized in that at least one selected from the group consisting of triacrylate (TMPTA), pentaerythritol triacrylate (PETA), dipentaerythritol hexaacrylate (DPHA). The method of claim 1, wherein the organic solvent is methanol, ethanol, isopropanol, normal-propanol, butanol, isobutanol, ethyl cellosolve, methyl cellosolve, butyl cellosolve, butyl acetate, diacetone alcohol, methyl Hard coating composition, characterized in that at least one selected from the group consisting of ethyl ketone, propylene glycol isopropyl alcohol, ethylene glycol isopropyl alcohol. delete The hard coating composition of claim 1 is coated on a plastic substrate and dried for 1 to 20 minutes under a temperature range of 40 ° C. to 80 ° C. to completely remove the organic solvent in the mixed composition, and then forms a coating film by irradiating with an ultraviolet light of 300 to 800 mJ / cm 2. Coating method of a plastic substrate, characterized in that it comprises a step. A hard coat sheet formed by the composition of claim 1. An image display device comprising the hard coat sheet of claim 12.

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