KR102062385B1 - Preparation of UV-Curable Hydrophilic Coating Films Using Colloidal Silica And Manufacturing Method Of Thereof - Google Patents

Abstract

The present invention, unlike the method of thermosetting the spin-coated coating film in a conventional drying oven, UV curing method hydrophilic coating film using a colloidal silica and a method of manufacturing the same, which rapidly improves the productivity and energy saving by UV curing method In the present invention, a colloidal silica dispersed in methanol is reacted with a silane coupling agent (MPTMS: 3-methacryloxypropyltrimethoxysilane) to prepare a first solution, which is an inorganic substance, and PETA (pentaerythritol triacrylate, which is a trifunctional acrylic monomer, which is an organic substance in the first solution). ) Is prepared by mixing an organic-inorganic hybridized second solution, followed by spin coating on a PC (polycarbonate) substrate, followed by UV curing.

Description

Preparation of UV-Curable Hydrophilic Coating Films Using Colloidal Silica And Manufacturing Method Of Thereof}

The present invention, unlike the method of thermosetting the spin-coated coating film in a conventional drying oven, UV curing method hydrophilic coating film using a colloidal silica and a method of manufacturing the same, which rapidly improves the productivity and energy saving by UV curing method In more detail, a colloidal silica dispersed in alcohol is reacted with a silane coupling agent (MPTMS: 3-methacryloxypropyltrimethoxysilane) to prepare a first solution, and the first solution is a trifunctional acrylic monomer which is an organic substance (pentaerythritol). The present invention relates to a UV-curable hydrophilic coating film using a colloidal silica prepared by mixing triacrylate) and preparing an organic-inorganic hybridized second solution, followed by spin coating on a PC (polycarbonate) substrate, and performing UV curing.

When the surface temperature of the solid is lower than the dew point of the atmosphere when moving from a low temperature environment to a high temperature and high humidity, water vapor in the air is condensed on the surface of the solid.

When the fog occurs on the surface of transparent plastic such as PMMA, PET or PC, transparency is reduced due to scattering of light due to condensed water vapor, which causes a big obstacle in use.

To solve this problem, two methods are used, one method is to heat the surface of the solid to prevent condensation of water vapor, and the other is to coat the surface of the transparent plastic with a hydrophilic material. Although the former method is efficient, energy consumption is high and there is a limit to use.

Hydrophilic coating refers to a method of applying a surfactant or a hydrophilic polymer to the surface of the plastic to remove water droplets to spread without forming on the surface.

However, this material alone is not secured because it is fixed on the plastic surface and does not maintain a consistent coating.

To compensate for this, many researchers have produced hydrophilic coating films showing long-term persistence by preparing organic-inorganic hybrids using wet chemical processes such as the sol-gel method.

On the other hand, as a curing method of the hydrophilic coating solution, there is a thermosetting method for curing using thermal energy.

However, the conventional thermosetting method requires a high temperature, a long time curing conditions in a drying oven, there is a problem that low productivity, high energy consumption.

Republic of Korea Patent Registration No. 0913371

The present invention has been made in view of the above problems, and the first object of the present invention, unlike the method of thermosetting the spin-coated coating film to a conventional dry oven, by rapid curing through UV curing method to improve productivity In addition, the present invention provides a UV curable hydrophilic coating film using colloidal silica and energy-saving method of manufacturing the same.

A second object of the present invention is to provide a photocurable hydrophilic coating solution by adding a photoinitiator, to provide a UV curable hydrophilic coating film using a colloidal silica to quickly cure the coating coating through the UV curing method and a method for producing the same. It is.

According to a feature for achieving the above object, the first invention relates to a method for producing a UV-curable hydrophilic coating film using a colloidal silica, to which a silane coupling agent is added to colloidal silica dispersed in an alcohol dispersion medium S10 step of obtaining a first solution by reacting for 2.5 to 3.5hr in a thermostat maintained at 60 ℃ ~ 80 ℃; and adding a trifunctional acrylic monomer PETA (pentaerythritol triacrylate) to the first solution and 60 ℃ ~ S20 step of obtaining a second solution by stirring at 80 ℃ for 1.5 ~ 2.5hr; And, by adding a photoinitiator to the second solution and stirred for 25 ~ 35min at 60 ℃ ~ 80 ℃ to obtain a photocurable hydrophilic coating solution S30 step; and, after the spin coating the hydrophilic coating solution on a PC (polycarbonate) substrate, and UV curing to complete the hydrophilic coating film; including, wherein the UV curing UV-A zero It is characterized by curing for 8 to 12 min using an inverse.

In the second invention, in the first invention, the colloidal silica is characterized in that the dispersion medium is methanol.

According to a third invention, in the first invention, the silane coupling agent is MPTMS (3-methacryloxypropyltrimethoxysilane, 99.9%, Sigma-Aldrich).

The fourth invention, in the first invention, the hydrophilic coating solution is a colloidal silica: silane coupling agent: acrylic monomer is 99.6 ~ 99.9% by weight of the second solution consisting of a weight ratio of 30 to 40: 10: 5, photoinitiator 0.2 ~ 0.4 It is characterized by consisting of weight percent.

The fifth invention is characterized in that in the fourth invention, the colloidal silica is composed of 70% by weight of methanol and 30% by weight of nanosilica.

The sixth invention relates to a UV curable hydrophilic coating film using colloidal silica, characterized in that it is produced through the manufacturing method of any one of the first to fifth invention.

According to the UV-curable hydrophilic coating film using the colloidal silica according to the present invention and a method for manufacturing the same, unlike the method of thermally curing the pin-coated coating film in a conventional drying oven, it is possible to improve the productivity by rapidly curing the coating film through the UV curing method In addition, energy is saved.

In addition, there is an effect that a coating film excellent in hydrophilicity can be produced by using a kind of dispersion medium as methanol and a silane coupling agent as MPTMS during UV curing.

1 is a flow chart of a method of manufacturing a UV curable hydrophilic coating film using a colloidal silica according to the present invention,
Figure 2 is a photograph of the samples S1, S2, S3, S4, S5 prepared by changing the amount of colloidal silica,
Figure 3 is a graph of the transmittance analysis of the coating film coated on a PC substrate with a hydrophilic coating solution prepared by adjusting the amount of colloidal silica,
4 is a surface photograph of a coating film obtained by coating a hydrophilic coating solution prepared by adjusting the amount of colloidal silica on a PC substrate at 100 times using an optical microscope,
5 is a water contact angle photograph of a coating film obtained by coating a hydrophilic coating solution prepared by adjusting the amount of colloidal silica on a PC substrate,
Figure 6 is a graph of the hydrophilic coating solution prepared by adjusting the amount of colloidal silica to analyze using FT-IR,
7 is a photograph of a hydrophilic coating solution prepared by changing the type of dispersion medium of colloidal silica into methanol, ethanol and isopropanol, respectively.
8 is a graph illustrating transmittance analysis of a UV cured coating film coated on a PC substrate with a coating solution prepared by changing a dispersion medium type of colloidal silica;
9 is a surface photograph of a UV cured coating film prepared by changing the type of dispersion medium of colloidal silica using an optical microscope,
10 is a water contact angle analysis graph of the UV cured coating film obtained by changing the type of dispersion medium of colloidal silica,
11 is a photograph of a hydrophilic coating solution prepared according to the type of silane coupling agent,
12 is a result of the transmittance analysis of the coating film prepared by changing the type of the silane coupling agent,
FIG. 13 is a contact angle photograph of water of a coating film coated on a PC substrate with a hydrophilic solution prepared by different kinds of silane coupling agents.

The following objects, other objects, features and advantages of the present invention will be readily understood through the following preferred embodiments associated with the accompanying drawings. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms.

Rather, the embodiments introduced herein are provided so that the disclosure may be made thorough and complete, and to fully convey the spirit of the present invention to those skilled in the art.

The embodiments described and illustrated herein also include complementary embodiments thereof.

In this specification, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, the words 'comprise' and / or 'comprising' do not exclude the presence or addition of one or more other components.

In describing the following specific embodiments, various specific details are set forth in order to more specifically explain and to help understand the invention. However, a person of ordinary skill in the art can understand that the present invention can be used without these various specific contents. In some cases, it is mentioned in advance that parts of the invention which are commonly known in the description of the invention and which are not highly related to the invention are not described in order to avoid confusion in describing the invention.

Hereinafter, a UV curable hydrophilic coating film using a colloidal silica according to the present invention and a method for preparing the same will be described in detail.

1 is a flowchart of a method of manufacturing a UV curable hydrophilic coating film using colloidal silica according to the present invention.

In step S10, a silane coupling agent is added to the colloidal silica dispersed in the alcohol dispersion medium and reacted for 2.5 to 3.5hr in a thermostat maintained at 60 ° C to 80 ° C to obtain a first solution.

The silane coupling agent for modifying the colloidal silica is preferably MPTMS (3-methacryloxypropyltrimethoxysilane, 99.9%, Sigma-Aldrich).

In addition, the colloidal silica preferably has a dispersion medium of methanol.

In step S20, a trifunctional acrylic monomer, PETA (pentaerythritol triacrylate), is added to the first solution well mixed with methanol as a dispersion medium, and stirred at 60 ° C to 80 ° C for 1.5 to 2.5hr to obtain a second solution.

In step S30, by adding a photoinitiator to the second solution and stirred for 25 to 35 minutes at 60 ℃ ~ 80 ℃ to obtain a photocurable hydrophilic coating solution.

The photoinitiator here is preferably X-CURE ^® PI-981 (CHEMPIA).

Meanwhile, the hydrophilic coating solution is comprised of 66.6-72.7 wt% of colloidal silica, 18.1-22.3 wt% of silane coupling agent, 9.0-11.2 wt% of acrylic monomer, and 0.2-0.4 wt% of photoinitiator.

In this case, the colloidal silica is composed of 70% by weight of methanol and 30% by weight of nanosilica.

In step S40, the hydrophilic coating solution is spin coated onto a PC (polycarbonate) substrate, and then UV cured to complete a hydrophilic coating film.

At this time, the UV curing may be cured for 8 to 12 minutes using a 300 ~ 400nm wavelength of the UV-A region to complete a hydrophilic coating film.

Experimental Example

UV Curing UV curing hydrophilic coating. Sample code Type of dispersion medium of colloidal silica Colloidal silica (g) MPTMS
(g) GPTMS
(g) MTMS
(g) VTES
(g) PETA
(g) S1 Methanol 10 10 0 0 0 5 S2 Methanol 20 10 0 0 0 5 S3 Methanol 30 10 0 0 0 5 S4 Methanol 40 10 0 0 0 5 S5 Methanol 50 10 0 0 0 5 S6 Methanol 30 10 0 0 0 5 S7 Ethanol 30 10 0 0 0 5 S8 Isopropanol 30 10 0 0 0 5 S9 Methanol 30 10 0 0 0 5 S10 Methanol 30 0 10 0 0 5 S11 Methanol 30 0 0 10 0 5 S12 Methanol 30 0 0 0 10 5

1. Method of Analysis

(1) transmittance

In order to measure the transmittance change in the visible region of the sample prepared in Table 1, coating solutions were coated on a PC substrate and UV cured to prepare a coating film, followed by UV-Visible Spectrometer (UV-2450, Shimadzu). The transmittance was measured in the range of 200-800 nm wavelength using.

(2) contact angle

In order to measure the contact angle of the coating film was observed using a contact angle meter (Pheonix-Mini, Surface Electro Optics). The zoom microscope was used to magnify the image on the surface to an optimal magnification, and water droplets were dropped on the surface. Then, the contact angle was measured by quantitative analysis using the monitor and the SurfaceWare9 program. Then, after connecting the computer and the CCD camera, the measured image was observed on the PC screen using the frame grabber to measure the contact angle.

(3) pencil hardness

For pencil hardness, insert the pencil hardness measuring pencil at a 45 ° angle into the pencil hardness measuring instrument (CT-PC1, Core Tech., Korea), apply a certain load (500 g), and push it 5 to 8 times to check the degree of scratching. Measured. Mitsubishi pencil was used as a pencil, and the pencil which showed the strength of H-9H, F, HB, B-6B etc. was used.

(4) adhesion

Adhesion of the coating film is to make a checkered groove on the UV cured coating film layer by ASTM D 3359, and then adhere the 3M tape on it well and peel off several times with a constant force to improve the adhesion between the coating layer and the substrate. Observed. 100 squares were made by crosswise cutting 11 × 11 at 1 mm intervals on the surface of the coated support, and the tape was attached and then pulled sharply to evaluate the surface. If the number of remaining eyes is 100, 5B, 95 or more, 4B, 85 or more are 3B, 65 or more are 2B, 35 or more are 1B, and less are 0B.

(5) microstructure

The surface shape of the coating film was observed 100 times using an optical microscope (CX31, OLYMPUS).

(6) FT-IR analysis

FT-IR (Cary 630, Agilent Technologies) was used to determine whether the surface of the nanoparticles in colloidal silica was surface modified with a silane coupling agent.

2. Analysis result according to the attached drawings

(1) Effect of Colloidal Silica Addition on the Physical Properties of Coating Coating Films

First, as shown in Figure 2, S1, S2, S3, S4, S5 samples of Table 1 can be confirmed that the transparent state, the more the amount of silica was found to increase the volume of the solution.

As shown in FIG. 3, the transmittance of the PC substrate showed a high transmittance of 90% in the visible light region. However, S1 and S2 samples with low silica content of 10g and 20g showed low transmittances of 55% and 80%, respectively. However, S3, S4 and S5 samples with more than 30 g of silica showed a high average transmittance of 90% as PC substrates. Through this, it was found that the transmittance of the coating film was improved only when the silica amount was added at least 30 g.

As shown in FIG. 4, colloidal particles are aggregated on the surfaces of the S1 and S2 samples having a small amount of colloidal silica, but the S3, S4, and S5 samples in which colloidal silica is added to a predetermined amount or more have a smooth surface without colloidal silica. The structure was shown. Due to the agglomeration of these colloidal silica particles, it can be seen from FIG. 3 that the transmittances of the S1 and S2 samples are low.

As shown in FIG. 5, the contact angles of the samples S1, S2, S3, S4, and S5 are 60 °, 56 °, 37 °, 41 °, It was found to be 56 ° and the contact angle of the S3 sample was 37 °, which was the smallest, indicating the best hydrophilicity. As the silica addition amount increased from 10g to 30g, the contact angle of the coating film decreased, but when the excess amount was added to 40g or more, the contact angle increased, indicating that there was an optimum value for the silica addition amount. This means that the silica particles were surface-modified with a predetermined amount (10 g) of MPTMS, a silane coupling agent, in order to fix colloidal silica, an inorganic material showing hydrophilicity, on the PC substrate, which is an organic material.

As shown in FIG. 6, as the amount of colloidal silica added increased, the peak intensity of the OH group in the 3,400 cm ⁻¹ region increased. In all samples, absorption peaks can be found at 2,982 cm ^-1 and 1,703 cm ^-1 , respectively, indicating the -CH ₃ and -C = O bonds of the silane coupling agent MPTMS. From this result, it can be seen that the surface modification of the colloidal silica surface was done by MPTMS in all samples.

As shown in FIG. 7, a translucent solution without precipitation of a hydrophilic coating solution prepared by changing the type of dispersion medium into methanol, ethanol and isopropanol, respectively was prepared.

As shown in FIG. 8, the transmittance of the PC substrate showed a high average transmittance of 90% in the visible light region. However, the S7 sample using ethanol as a colloidal silica dispersion medium showed a low average transmittance of 80% in the visible region, while the coating films (S6 and S8) using methanol or isopropanol showed a good average transmittance of 90% similar to that of the PC substrate. Indicated.

As shown in FIG. 9, the surfaces of the S6 and S8 samples showed a smooth structure without aggregation of silica particles, but the surface of the S7 sample dispersed in ethanol was found to have a colloidal phenomenon of colloidal particles. The average transmittance was observed as low as 80%.

As shown in FIG. 10, the contact angles of the coating films prepared by changing the type of dispersion medium to methanol, ethanol, and isopropanol were 37 °, 51 °, and 56 °, respectively. As a result, it was found that the contact angle of the UV cured coating film increased as the molecular weight of the colloidal silica dispersion medium increased.

Pencil hardness and adhesion of the UV curable coating film prepared by adjusting the amount of colloidal silica is measured. Sample code Pencil hardness Adhesion PC plate B - S1 H 5B S2 H 5B S3 H 5B S4 H 5B S5 H 4B S6 H 5B S7 H 5B S8 H 5B S9 H 5B S10 F 5B S11 H 5B S12 H 4B

Table 2 shows the measurement results of the physical properties of the coating films (S6, S7, S8) coated on the PC substrate with a hydrophilic coating solution prepared by changing the type of dispersion medium of colloidal silica. Adhesion was shown. The above results indicate that the type of dispersion medium of colloidal silica affects the hydrophilicity and permeability of the coating film, but does not affect the pencil hardness and adhesion of the coating film.

In addition, the physical properties of the coating film prepared by varying the type of silane coupling agent, as shown in Table 2, the pencil hardness and adhesion of the S9 and S11 samples prepared using MPTMS and MTMS (methyltrimethoxysilane) were H and 5B. The S10 sample using GPTMS (3-glycidoxypropyltrimethoxysilane) did not have good pencil hardness of F, and the adhesion of S12 sample using VTES was not good as 4B. It has a great influence on the physical properties of the.

(2) Effect of Type of Silane Coupling Agent on the Properties of Coating Coating Film

 The amount of silane coupling agent that surface-modifies colloidal silica at 30 g and the optimum value of colloidal silica addition and dispersant type experiments conducted above were changed to MPTMS, GPTMS, MTMS, and VTES (vinyltrimethoxysilane), respectively. Four kinds of coating solutions, S10, S11 and S12, were prepared to investigate the effect of the silane coupling agent on the physical properties of the coating film.

As shown in FIG. 11, solutions prepared using MPTMS, GPTMS and MTMS showed a stable state of translucency and no precipitation, but the S12 sample made of VTES showed an unstable state in which precipitates were suspended.

As shown in FIG. 12, the S9, S10, S11, and S12 samples obtained by changing the silane coupling agent showed high transmittances as in the PC substrate with an average transmittance of 90% in the visible light region. There was no.

As shown in Figure 13, the contact angle of the samples made of MPTMS, GPTMS, MTMS, VTES showed a large difference depending on the type of silane coupling agent, respectively 37 °, 40 °, 49 °, 69 °, prepared using MPTMS The contact angle of the S9 sample was the lowest at 37 °, showing the best hydrophilicity.

It can be seen that MPTMS, which is an acrylic silane, exhibits excellent hydrophilicity upon UV curing compared to epoxy silane (GPTMS), methyl silane (MTMS) or vinyl silane (VTES).

3. Conclusion

The colloidal silica dispersed in alcohol was reacted with PETA, an acrylic monomer, to prepare an organic-inorganic hybrid solution, coated on a PC substrate, and then UV cured to prepare a hydrophilic coating film. In this process, the influence of reaction variables on the physical properties of the coating film was investigated.

(1) The contact angles of the samples prepared by changing the colloidal silica amount from 10 to 50 g were 60 °, 56 °, 37 °, 41 °, As the contact angle of the sample prepared with a colloidal silica amount of 30 g at 56 ° was the lowest, it was found that the hydrophilic property was the best.

The hydrophilic coating solution prepared by adjusting the amount of colloidal silica was analyzed using FT-IR. As a result, the surface of the colloidal silica was modified by MPTMS in all samples.

(2) The contact angles of the coating films prepared by changing the type of dispersion medium in which the silica nanoparticles were dispersed under methanol and ethanol and isopropanol, respectively, were fixed at 30 g of colloidal silica at 37 °, 51 °, and 56 °, respectively. The dispersed case was the most hydrophilic.

However, the pencil hardness and adhesion of the coating film did not show a significant difference depending on the type of colloidal silica dispersion medium.

(3) The contact angles of the coating films prepared by different types of silane coupling agents from MPTMS, GPTMS, MTMS, and VTES were 37 °, 40 °, 49 °, The hydrophilicity was the best when the contact angle was 69 ° and was made of MPTMS, which was an acrylic silane.

The rights of the present invention are not limited to the embodiments described above, but are defined by the claims, and those skilled in the art can make various modifications and adaptations within the scope of the claims. It is self-evident.

Claims (6)

Adding a silane coupling agent to colloidal silica dispersed in an alcohol dispersion medium and reacting for 2.5 to 3.5hr in a thermostat maintained at 60 ° C to 80 ° C to obtain a first solution;
S20 step of obtaining a second solution by adding a trifunctional acrylic monomer PETA (pentaerythritol triacrylate) to the first solution and stirred at 60 ℃ ~ 80 ℃ for 1.5 ~ 2.5hr;
Adding a photoinitiator to the second solution and stirring at 60 ° C. to 80 ° C. for 25 to 35 min to obtain a photocurable hydrophilic coating solution;
S40 step of spin-coating the hydrophilic coating solution on a PC (polycarbonate) substrate, followed by UV curing to complete a hydrophilic coating film;
The colloidal silica is a dispersion medium is methanol,
The silane coupling agent is MPTMS (3-methacryloxypropyltrimethoxysilane, 99.9%, Sigma-Aldrich),
The hydrophilic coating solution comprises a colloidal silica: silane coupling agent: acrylic monomer is composed of 99.6 to 99.9% by weight of the second solution consisting of a weight ratio of 30 to 40: 10: 5, and 0.2 to 0.4% by weight of the photoinitiator,
The colloidal silica is composed of 70% by weight of methanol, 30% by weight of nanosilica,
The UV curing UV curable hydrophilic coating film manufacturing method using a colloidal silica, characterized in that for 8 to 12 minutes using a UV-A region.
delete delete delete delete UV-curable hydrophilic coating film using a colloidal silica, characterized in that produced through the manufacturing method of claim 1.

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