KR102600028B1 - Antibacterial hard coating film and preparation method thereof - Google Patents

Abstract

The present invention is an antibacterial hard coating film using a roll-to-roll coating process and a method for manufacturing the same. A hard coating liquid composition comprising an optical film substrate (PET or TAC) mixed with an ultraviolet curable hard coating resin, additives, and antibacterial agents. It relates to a polarizing film for displays with antibacterial function and a method of manufacturing the same. By controlling the solid content of the hard coating resin and the content of additives and antibacterial agents, it is possible to produce an antibacterial film with excellent transparency, wear resistance, hardness, and antibacterial performance.

Description

Antibacterial hard coating film and preparation method thereof}

The present disclosure relates to antibacterial hard coating films and methods for making the same.

With technological advancements in displays and peripheral devices, mobile phones, laptops, and tablet PCs have recently been released with touch-enabled front displays. Individuals use one or more devices with touch-type displays, and many government offices and public places use them. As expected, devices with touch-type displays are used.

In particular, devices used in public places have a high possibility of the proliferation of various bacteria as an unspecified number of people touch the display of the device. Recently, with the advent of the pandemic era where various infectious diseases such as COVID-19 and monkeypox threaten daily life, the need for antibacterial materials is increasing. is attracting attention, and the demand for displays using these antibacterial materials is increasing.

Therefore, there is a need to develop a polarizing film for displays that has the basic physical properties required for displays, such as clear image quality (high transmittance) and scratch resistance (wear resistance), while also having excellent antibacterial performance.

Meanwhile, the base film of the antibacterial hard coating film is hygroscopic due to the nature of the base material, so the base film is easily deformed by moisture, and when the base film is wound and stored in a roll, the phenomenon of fabric pressing occurs. This pressing phenomenon of the fabric has the problem of causing coating defects when applying the coating solution, so there is a need to improve this. In addition, the rainbow phenomenon that occurs during hard coating film manufacturing is defined as an optical phenomenon caused by minute differences in coating thickness during precision coating. Light is reflected diffusely due to the imbalance between the substrate and the coating film, and color bleeding or staining occurs when observed with the naked eye. It is observed that it affects the appearance of the film, so there is a need to improve it.

In one aspect, it is intended to provide a hard coating film with antibacterial function.

In one aspect, an object is to provide an antibacterial hard coating film for application to a polarizing film for displays.

In one aspect, an object is to provide a method for manufacturing an antibacterial hard coating film.

In order to achieve the above object, in one aspect, the present invention includes a base film and a coating film, wherein the coating film includes a hard coating resin; additive; and an antibacterial hard coating film comprising a hard coating liquid composition containing an antibacterial agent.

In another aspect, the present invention provides a method for producing an antibacterial hard coating film, comprising: (a) a hard coating resin; additive; and mixing an antibacterial agent to prepare a hard coating liquid composition; (b) depositing the hard coating liquid composition on a base film; and (c) drying the base film on which the hard coating liquid composition is deposited to remove the solvent.

Coating solution mixing technology is an important technology that determines important properties such as wear resistance, hardness, and antibacterial performance required for display materials. Using the above technology, the antibacterial hard coating film of the present invention has a clear image quality and scratch prevention function, and can be used in touch-type display devices, which are on the rise recently, due to its excellent antibacterial performance.

In addition, the antibacterial hard coating film of the present invention has a good curl level and a good rainbow phenomenon, and the manufacturing method of the film has the effect of improving the wrinkles of the fabric and reducing the coating defect rate.

Figure 1 is a schematic diagram showing a cross section 100 of an antibacterial hard coating film.
Figure 2 is an image confirming the dispersion stability of the hard coating resin and antibacterial agent.
Figure 3 is an image showing the pressing of the base film fabric (a), the resulting coating defect (b), and the formation of wrinkles in the MD direction (c).
Figure 4 is an image showing a method for evaluating the curl level of an antibacterial hard coating film.

Hereinafter, the present invention will be described in detail.

In one aspect, the present invention includes a base film and a coating film, wherein the coating film includes a hard coating resin; additive; It provides an antibacterial hard coating film consisting of a hard coating liquid composition containing an antibacterial agent. Specifically, the antibacterial hard coating film has a cross section as shown in Figure 1, that is, a hard coating resin on the top of the base film; additive; and a coating film made of a hard coating liquid composition containing an antibacterial agent is deposited.

In one embodiment, the antibacterial agent may be included in an amount of 0.5 to 1.0% by weight based on the weight of the hard coating resin. For example, the antibacterial agent is present in an amount of 0.5% by weight or more, 0.51% by weight or more, 0.52% by weight or more, 0.53% by weight or more, 0.54% by weight or more, 0.55% by weight or more, 0.56% by weight or more, 0.57% by weight or more, 0.58% by weight. or more, 0.59 weight% or more, 0.6 weight% or more, 0.61 weight% or more, 0.62 weight% or more, 0.63 weight% or more, 0.64 weight% or more, 0.65 weight% or more, 0.66 weight% or more, 0.67 weight% or more, 0.68 weight% or more, 0.69% by weight or more, 0.68% by weight or more, 0.69% by weight or more, 0.7% by weight or more, 0.71% by weight or more, 0.72% by weight or more, 0.73% by weight or more, 0.74% by weight or more, 0.75% by weight or more, 1.0% by weight or less, 0.99 weight% or less, 0.98 weight% or less, 0.97 weight% or less, 0.96 weight% or less, 0.95 weight% or less, 0.94 weight% or less, 0.93 weight% or less, 0.92 weight% or less, 0.91 weight% or less, 0.9 weight% or less or less, 0.89 weight% or less, 0.88 weight% or less, 0.87 weight% or less, 0.86 weight% or less, 0.85 weight% or less, 0.84 weight% or less, 0.83 weight% or less, 0.83 weight% or less, 0.82 weight% or less, 0.81 weight% Or less, it may be 0.8 wt% or less, 0.79 wt% or less, 0.78 wt% or less, or 0.77 wt% or less, or 0.76 wt% or less.

In one embodiment, the antibacterial agent may include at least one selected from metal oxide salts and silver salts. Examples of the metal oxide salt include, but are not limited to, zinc oxide, calcium oxide, silver nitrate, copper sulfate, zinc sulfate, calcium phosphate, and zirconium phosphate.

In one embodiment, the hard coating resin includes solid content and a solvent, and the solid content may be included in an amount of 30 to 40% by weight based on the total weight of the hard coating resin. For example, the weight of the solid content is 30% by weight or more, 30.5% by weight or more, 31% by weight or more, 31.5% by weight or more, 32% by weight or more, 32.5% by weight or more, 33% by weight or more, 33.5% by weight or more, 34 Weight% or more, 34.5 weight% or more, 35 weight% or more, 40 weight% or less, 39.5 weight% or less, 39 weight% or less, 38.5 weight% or less, 38 weight% or less, 37.5 weight% or less, 37 weight% or less, 36.5 It may be less than or equal to 36 weight percent, or less than or equal to 35.5 weight percent.

In one embodiment, the hard coating resin may be an ultraviolet curable resin. The ultraviolet curable compound refers to a compound that causes a polymerization reaction when irradiated with light in the ultraviolet range. The amount of ultraviolet rays may be from 600 mJ/cm ² to about 800 mJ/cm ² . For example, more than 600 mJ/cm ² , more than 610 mJ/cm ² , more than 620 mJ/cm ² , more than 630 mJ/cm ² , more than 640 mJ/cm ² , more than 650 mJ/cm ² , 660 mJ/cm 2 or more ² or more, 670 mJ/cm ² or more, 680 mJ/cm ² or more, 690 mJ/cm ² or more, 700 mJ/cm ^{2 or} more, 800 mJ/cm ² or less, 790 mJ/cm ² or less, 780 mJ/cm ² or less, 770 mJ/cm ² or less, 760 mJ/cm ² or less, 750 mJ/cm ² or less, 740 mJ/cm ^{2 or} less, 730 mJ/cm ² or less, 720 mJ/cm ² or less, or 710 mJ/cm ^{2 or less} . It may be below. The light source for ultraviolet irradiation is not particularly limited as long as it can be used in the technical field to which this technology belongs. For example, a high-pressure mercury lamp, a metal halide lamp, a black light fluorescent lamp, etc. can be used.

In one embodiment, the ultraviolet curable resin may be an acrylate-based ultraviolet curable resin. As the acrylate-based UV resin, a multifunctional acrylate-based monomer or a multifunctional urethane acrylate-based oligomer may be used.

In one embodiment, the hard coating resin may be a resin containing charging performance. Specifically, to prevent the antibacterial hard coating film from being charged, a resin containing antistatic performance is used.

In one embodiment, the additive may be a fluorine-based leveling agent. The leveling agent is added to adjust the surface smoothness of the antibacterial film according to one embodiment of the present invention.

In one embodiment, the additive may be included in an amount of 0.001 to 0.1% by weight based on the weight of the hard coating resin. For example, the additive is present in an amount of 0.001% by weight or more, 0.005% by weight or more, 0.01% by weight or more, 0.013% by weight or more, 0.015% by weight or more, 0.017% by weight or more, 0.02% by weight or more, 0.025% by weight or more, 0.03% by weight. It may be included in an amount of 0.04% by weight or more, 0.05% by weight or more, 0.1% by weight or less, 0.09% by weight or less, 0.08% by weight or less, 0.07% by weight or less, or 0.06% by weight or less.

In one embodiment, the thickness of the coating film may be 3 to 6 μm. For example, the thickness is 3 μm or greater, 3.1 μm or greater, 3.2 μm or greater, 3.3 μm or greater, 3.4 μm or greater, 3.5 μm or greater, 3.6 μm or greater, 3.7 μm or greater, 3.8 μm or greater, 3.9 μm or greater, 4 μm or greater. , 4.1 μm or more, 4.2 μm or more, 4.3 μm or more, 4.4 μm or more, 4.5 μm or more, 6 μm or less, 5.9 μm or less, 5.8 μm or less, 5.7 μm or less, 5.6 μm or less, 5.5 μm or less, 5.4 μm or less, 5.3 It may be less than or equal to a μm, less than or equal to 5.2 μm, less than or equal to 5.1 μm, less than or equal to 5 μm, less than or equal to 4.9 μm, less than or equal to 4.8 μm, less than or equal to 4.7 μm, or less than or equal to 4.6 μm. If the thickness of the coating film is less than 3 μm, the wear resistance and hardness of the film are poor, the rainbow phenomenon is poor, and if the thickness of the coating film exceeds 6 μm, the curl level of the film is poor.

In one embodiment, the antibacterial hard coating film may be applied to a polarizing film, and the polarizing film may be used for a display. Therefore, the antibacterial hard coating film may be transparent.

In one embodiment, the thickness of the base film may be 40 to 60 μm. For example, the thickness is 40 μm or more, 40.5 μm or more, 41 μm or more, 41.5 μm or more, 42 μm or more, 42.5 μm or more, 43 μm or more, 43.5 μm or more, 44 μm or more, 44.5 μm or more, 45 μm or more , 45.5 μm or more, 46 μm or more, 46.5 μm or more, 47 μm or more, 47.5 μm or more, 48 μm or more, 48.5 μm or more, 49 μm or more, 49.5 μm or more, 50 μm or more, 60 μm or less, 59.5 μm or less, 59 μm or less, 58.5 μm or less, 58 μm or less, 57.5 μm or less, 57 μm or less, 56.5 μm or less, 56 μm or less, 55.5 μm or less, 55 μm or less, 54.5 μm or less, 54 μm or less, 53.5 μm or less, 53 μm or less , may be 52.5 μm or less, 52 μm or less, 51.5 μm or less, 51 μm or less, or 50.5 μm or less.

In one embodiment, the base film may include at least one of polyethylene terephthalate (PET) and triacetyl cellulose (TAC).

In another aspect, the present invention provides a method for producing the antibacterial hard coating film, comprising: (a) a hard coating resin; additive; and mixing an antibacterial agent to prepare a hard coating liquid composition; (b) preparing the base film; and (c) coating the base film with the hard coating liquid composition.

In one embodiment, (b) may involve pre-heat treating the base film before performing (c). Specifically, heat treatment prevents shrinkage of the base film and controls defects, thereby reducing the rate of coating defects.

In one embodiment, (c) may be a roll-to-roll method. Specifically, roll-to-roll coating is a method for coating the surface of a flexible substrate such as a film, and includes coating methods such as slot die coater, gravure coater, and inkjet printing. The roll-to-roll coating method unwinds the substrate at the beginning, rewinds the substrate, and goes through a coating process on the substrate to form a coating film and passes it through drying and curing steps to achieve physical properties suitable for the application. A functional film that implements is manufactured. This has the advantage of securing productivity per unit time because continuous or high-speed coating is possible.

In one embodiment, the heat treatment may be a stepwise application of the heat treatment temperature.

In one embodiment, the stepwise heat treatment includes (b1) heat treatment at a temperature of 70 to 80 °C; (b2) heat treatment at a temperature of 85 to 95°C; (b3) heat treatment at a temperature of 90 to 100°C; and (b4) heat treatment at a temperature of 50 to 70°C. The heat treatment in step (b1) is, for example, 70 ℃ or higher, 71 ℃ or higher, 72 ℃ or higher, 73 ℃ or higher, 74 ℃ or higher, 75 ℃ or higher, 80 ℃ or lower, 79 ℃ or lower, 78 ℃ or lower, 77 ℃ It may be carried out below, or below 76°C. The heat treatment in step (b2) is, for example, 85°C or higher, 86°C or higher, 87°C or higher, 88°C or higher, 89°C or higher, 90°C or higher, 95°C or lower, 94°C or lower, 93°C or lower, and 92°C. It may be carried out at or below 91°C. The heat treatment in step (b3) is, for example, 90°C or higher, 91°C or higher, 92°C or higher, 93°C or higher, 94°C or higher, 95°C or higher, 100°C or lower, 99°C or lower, 98°C or lower, and 97°C. It may be carried out at a temperature of 96° C. or lower. The heat treatment in step (b4) is, for example, 50℃ or higher, 51℃ or higher, 52℃ or higher, 53℃ or higher, 54℃ or higher, 55℃ or higher, 56℃ or higher, 57℃ or higher, 58℃ or higher, 59℃ or higher. Performed at temperatures above 60°C, below 70°C, below 69°C, below 68°C, below 67°C, below 66°C, below 65°C, below 64°C, below 63°C, below 62°C, or below 61°C. It can be.

In one embodiment, (d) may further include irradiating ultraviolet rays. Specifically, ultraviolet rays may be irradiated to cure the hard coating resin included in the hard coating liquid composition.

In one embodiment, the ultraviolet rays may be irradiated at a light quantity of 600 mJ/cm ² to about 800 mJ/cm ² . For example, more than 600 mJ/cm ² , more than 610 mJ/cm ² , more than 620 mJ/cm ² , more than 630 mJ/cm ² , more than 640 mJ/cm ² , more than 650 mJ/cm ² , 660 mJ/cm 2 or more ² or more, 670 mJ/cm ² or more, 680 mJ/cm ² or more, 690 mJ/cm ² or more, 700 mJ/cm ^{2 or} more, 800 mJ/cm ² or less, 790 mJ/cm ² or less, 780 mJ/cm ² or less, 770 mJ/cm ² or less, 760 mJ/cm ² or less, 750 mJ/cm ² or less, 740 mJ/cm ^{2 or} less, 730 mJ/cm ² or less, 720 mJ/cm ² or less, or 710 mJ/cm ^{2 or less} . The following amount of light may be irradiated.

Hereinafter, the contents of the present invention will be described in more detail through examples. However, these examples are only presented to understand the content of the present invention, and the scope of the present invention is not limited to these examples, and modifications, substitutions, and insertions commonly known in the art can be performed. It can be done, and this is also included in the scope of the present invention.

Example

One. Evaluation of the dispersion stability of the composition

A dispersion stability evaluation was conducted to confirm the compatibility between the hard coating resin and the antibacterial agent. (1) The solid content of the hard coating resin (AS-108) was fixed at 25% of the total weight, (2) the antibacterial agent content was added at 0.5, 1.0, 1.5, and 2.0% by weight relative to the weight of the hard coating resin, and (3) 5%. After magnetic stirring for 10 to 10 minutes, (4) the mixture was left at room temperature and the dispersion state was observed for the 1st, 5th, and 7th days, and is shown in Table 1 and Figure 2. In Table 1, “○” indicates that the dispersion state is good, and “white turbidity” means that the dispersion state is poor and a white turbidity phenomenon appears.

Looking at Figure 2, an image confirming the dispersion stability when the antibacterial agent content is included in (a) 0.5% by weight, (b) 1.0% by weight, (c) 1.5% by weight, and (d) 2.0% by weight of the weight of the hard coating resin. am. As shown in Figure 2 and Table 1, in the case of a composition containing an antibacterial agent at 0.5 to 1.0% by weight of the hard coating resin weight, no clouding phenomenon appeared until the 7th day, but when it was included at 1.5% by weight or more, a clouding phenomenon appeared from the 1st day. This appeared prominently.

2. Evaluation of antibacterial activity of film according to antibacterial agent content

The hard coating resin was tested based on 10 g. The solid content of the hard coating resin is fixed at 25% by weight based on the total weight of the hard coating resin, the fluorine-based leveling agent as an additive is fixed at 0.013% by weight based on the total weight of the hard coating resin, and the antibacterial agent is fixed at 0.013% by weight based on the total weight of the hard coating resin. A hard coating liquid composition was prepared by adding 0.5 to 2.0% by weight and magnetically stirring for 5 to 10 minutes.

Reliability evaluation (constant temperature and humidity test) was conducted to accurately evaluate antibacterial activity. The thermostat was set to a temperature of 60°C and a humidity of 90%, and the evaluation time was set to 168 hours and 500 hours. The prepared antibacterial hard coating film was put into a set constant temperature and humidity chamber, recovered after the specified time, and an antibacterial test was performed (test method: JIS Z 2801, test site: KSTR Korea Standards and Research Institute). The results are shown in Table 2. The antibacterial test evaluation method is as follows: (1) Prepare a total of 6 specimens of the manufactured antibacterial film with a size of 50mm in width and 50mm in height. (2) Prepare the virus strain to be used for testing. (3) Apply the solution containing the virus strain to the specimen to be tested. (4) Rinse the specimen after the specified time. (5) Assess whether the cells are infected by exposing them to the rinsing solution.

As a result of the test, antibacterial performance could be secured when the antibacterial agent content was 0.5 to 1.0% by weight based on the weight of the hard coating resin, but antibacterial performance could not be secured when the content was 1.5 to 2.0% by weight. When the antibacterial agent content is 0.5 to 1.0% by weight, antibacterial performance can be maintained even in constant temperature and humidity tests of 168 hours and 500 hours. As a result, the appropriate content of the antibacterial agent in the hard coating liquid composition is 0.5 to 1.0% by weight based on the weight of the hard coating resin.

3. Evaluation of physical properties according to UV light intensity and hard coating film thickness

The solid content of the hard coating resin is included at 25% or 35% by weight of the total weight of the hard coating resin. To reduce the variation in coating film thickness, 0.013% by weight of a fluorine-based leveling agent is added based on the weight of the hard coating resin. To provide antibacterial performance, 1% by weight of the hard coating resin was added as an antibacterial agent.

The prepared hard coating liquid composition was coated on the TAC base film according to the application amount and passed through a hot air dryer and a high pressure Hg UV irradiator to prepare a hard coating film. The thickness of the produced coating film was measured, and the abrasion resistance (steel wool), pencil hardness, and adhesion of the produced film were evaluated.

The abrasion resistance (steel wool) evaluation method is as follows: (1) Prepare a specimen by cutting the manufactured antibacterial hard coating film into 150mm horizontal (TD) and 50mm vertical (MD). (2) In the case of steel wool, it is tested with Bonstar #0000, and a total of 10 round-trip tests are performed at a speed of 100 mm/sec under a load of 500 g. (3) Calculate the number of scratches after the test. After the steel wool test, if the scratch was within 2EA, it was evaluated as PASS.

The pencil hardness evaluation method is as follows: (1) Prepare a specimen by cutting the produced antibacterial film into 100mm width and 50mm length. (2) Using a designated pencil, fix it in contact with the sample at a 45 degree angle and then test at a speed of 30 mm/min. (3) Calculate the number of scratches after the test. After the pencil hardness test, if there were no scratches more than 3 out of 5 times, it was evaluated as PASS.

The results are shown in Table 3 below.

As a result, referring to Comparative Examples 1B and 2B, there is no effect of improving wear resistance when the amount of UV light increases. Referring to Comparative Example 3B and Example 1B, wear resistance was improved as the solid content of the hard coating resin increased. This is because the amount of volatile solvent decreases as the solid content increases. In other words, it is believed that the degree of cure increases as the solid content of the hard coating resin increases and the amount of solvent decreases. Referring to Comparative Example 3B, Example 1B, and Example 2B, it can be seen that differences in wear resistance and hardness performance occur at similar coating film thicknesses. Likewise, as the solvent content of the hard coating resin decreases, the resin solid content increases. It can be seen that the wear resistance and hardness performance increase as time increases. Referring to Examples 1B to 4B, it can be seen that as the coating film thickness increases, wear resistance and pencil hardness performance are improved.

4. Evaluation of appearance defects through application of pre-heat treatment process

TAC base films are known to be hygroscopic due to the nature of the base material. Therefore, deformation of the substrate due to moisture easily occurs, and when the TAC film is wound and stored in a roll, the fabric is pressed, as shown in Figure 3(a). When a coating solution is applied to a base film that has a fabric pressing phenomenon, coating defects occur as shown in FIG. 3(b). In addition, due to the nature of the TAC film, heat shrinkage in the MD (Machine Direction) / TD (Transverse Direction) direction frequently occurs, which causes MD wrinkles in the traveling direction as shown in Figure 3(c) after coating. This results in appearance defects. Therefore, it is essential to apply a pre-heat treatment process before coating to prevent substrate shrinkage and control defects.

The pre-heat treatment process is a step that prevents compression and shrinkage of the fabric in advance by applying the appropriate temperature and air volume before the substrate is released from the fabric unwinder during the roll to roll process and reaches the coating head. The pre-heat treatment equipment applied in the present invention consists of five zones, and the air volume for each zone was fixed at 35-35-35-35-35 Hz and the effect was evaluated by varying the temperature for each zone.

For the UV curing process, a high pressure mercury lamp (High pressure Hg) is applied, and the amount of light can be adjusted by dividing UV curing into three zones.

The appearance of the film manufactured as described above (marks, i.e. coating defects, coating foreign matter, wrinkles, etc.) was inspected in the following order using a three-wavelength fluorescent lamp as a light source. (1) Carefully unwrap the collected sample into 1M length. (2) Move the sample up and down and focus your eyes on the image of the coated surface shown by the light source. (3) While winding the sample, inspect the coated surface all the way to the end. (4) The examiner's gaze is directed from the bottom left to the right, then up, and then to the left. The test is performed without any gaps. (5) When a defect occurs, mark the defective part of the product with a permanent mark. The results are shown in Table 4.

Referring to Comparative Example 1C and Comparative Example 2C, when pre-heat treatment is not applied, wrinkles in the MD direction occur due to pressing of the fabric, and coating defects occur accordingly. Referring to Comparative Example 3C and Comparative Example 4C, when applying pre-heat treatment, MD wrinkles were slightly improved and the number of coating defects was reduced. Referring to Comparative Example 5C, when the pre-heat treatment temperature is applied step by step, the number of coating defects due to MD wrinkle improvement is greatly reduced. Referring to Example 1C and Example 2C, when the pre-heat treatment temperature is applied step by step and the UV light amount is adjusted, there are no MD wrinkles and the appearance level is good with less than 0.6 coating defects.

* Transmission Haze and colorimetric measurement formulas and units

T.T (total spectral transmittance) = T.p (parallel transmittance) + Td (diffuse transmittance)

Haze (turbidity) = Td (diffuse transmittance) / Tt (total light transmittance) * 100%

Color difference value: Expressed as a constant as L* (+:white,-:black), a* (+:red,-:green), b* (+:yellow,-:blue)

5. Improvement of rainbow phenomenon depending on solid content of hard coating resin

The rainbow phenomenon that occurs during hard coating film manufacturing is defined as an optical phenomenon caused by minute differences in coating thickness during precision coating. It appears as light is diffusely reflected due to the interfacial imbalance between the substrate and coating film, and when observed with the naked eye, it appears as color bleeding or staining. is observed. To improve this, the present invention provides rainbow level control by changing the solid content of the hard coating resin, rainbow level control by coating film thickness control, and rainbow level control by 'mixing-area' effect using chemical reaction between the base film and solvent. I would like to present the effect.

The main solvent components of hard coating resin (Arakawa Chemical, AS-108) include PGME, MEK, and MIBK, and the ratio is PGME:MEK:MIBK=41:49:10. The rainbow phenomenon is caused by the vaporization of MEK, which is classified as a low boiling point solvent, and the rainbow that occurs from the vaporization of the solvent is commonly referred to as 'solvent mura'. MEK (Methyl ethyl ketone) is basically classified as a ketone and has polar characteristics. In the case of most ketones, they often penetrate deep into the plastic material and remain there, which is called 'erosion', and this can also cause a white clouding phenomenon in the material.

The solid content of the hard coating resin is set to 25% or 35% by weight based on the total weight of the hard coating resin, and the thickness of the coating film is kept constant at 3 μm. After coating on the base film, the erosion layer thickness and rainbow phenomenon are observed. observed. The visual evaluation method for the rainbow phenomenon is as follows: An antibacterial film was attached to Black PET Tape at room temperature and observed from a 15-degree angle. “○” indicates a good rainbow level, “△” indicates a weak rainbow, and “X” indicates a severe rainbow. The results are listed in Table 5.

Referring to Example 4A and Comparative Example 4B, when the solid content of the hard coating resin was applied at 35% by weight, erosion occurred at a low level, and the solvent mura effect was reduced accordingly, indicating a good rainbow level. In other words, as the hard coating resin solid content increases, the thickness of the erosion layer decreases, indicating that the rainbow level is improved when relatively little erosion occurs.

6. Improved rainbow and curl phenomenon depending on coating thickness

Table 6 shows the results of comparing the rainbow phenomenon and curl phenomenon observed when the hard coating resin solid content was fixed at 35% by weight and the film thickness was varied. The visual evaluation method for the rainbow phenomenon is as described above, and the curl phenomenon evaluation method is as follows: (1) The prepared antibacterial film is cut to a certain size. (ex. TD direction 1.5M (3) After leaving for a certain period of time, measure with a ruler how much curl occurs in the direction of the coating surface, as shown in Figure 4. (4) Curl less than 40 mm is judged as good (“○”)/exceeding 40 mm is judged as NG (“X”)

Referring to Comparative Example 5A, the rainbow level observed when the coating film thickness was formed to be less than 3 μm was observed to be somewhat poor, and when the coating film thickness was slightly increased to 5 to 6 μm, the rainbow level was improved, and the curl level also improved. It appears to be good. However, referring to Comparative Example 5B, the rainbow level observed when the coating film thickness is 7 to 10 μm is found to be good, but the curl level is poor. This means that as the thickness of the coating film increases, the rainbow phenomenon is judged to have improved as the diffuse reflection occurring at the interface between the substrate and the coating film layer decreases, and the curl level becomes poorer.

100: Antibacterial hard coating film
110: coating film
120: Base film

Claims (16)

Includes a base film and a coating film,
The coating film is composed of a hard coating liquid composition containing hard coating resin, additives, and antibacterial agents,
An antibacterial hard coating film, wherein the antibacterial agent is included in an amount of 0.5 to 1.0% by weight based on the weight of the hard coating resin. According to paragraph 1,
An antibacterial hard coating film, wherein the antibacterial agent includes at least one selected from metal oxide salts and silver salts. According to paragraph 1,
The hard coating resin contains solids and a solvent,
An antibacterial hard coating film, wherein the solid content is contained in an amount of 30 to 40% by weight based on the total weight of the hard coating resin. According to paragraph 1,
The hard coating resin is an antibacterial hard coating film that is an ultraviolet curable resin. According to paragraph 4,
The ultraviolet curable resin is an antibacterial hard coating film that is an acrylate-based ultraviolet curable resin. According to paragraph 1,
The additive is a fluorine-based leveling agent, an antibacterial hard coating film. According to paragraph 1,
The antibacterial hard coating film has a thickness of 3 to 6 μm. According to paragraph 1,
An antibacterial hard coating film wherein the base film has a thickness of 40 to 60 μm. According to paragraph 1,
The base film is an antibacterial hard coating film comprising at least one of polyethylene terephthalate (PET) and triacetyl cellulose (TAC). A method for producing an antibacterial hard coating film according to any one of claims 1 to 9, comprising:
(a) hard coating resin; additive; and mixing an antibacterial agent to prepare a hard coating liquid composition;
(b) preparing the base film; and
(c) coating the hard coating liquid composition on the base film,
(b) is to pre-heat treat the base film before performing (c),
The pre-heat treatment includes (b1) heat treatment at a temperature of 70 to 80°C; (b2) heat treatment at a temperature of 85 to 95°C; (b3) heat treatment at a temperature of 90 to 100°C; And (b4) heat treatment at a temperature of 50 to 70°C; including, applying the heat treatment temperature in stages,
Manufacturing method of antibacterial hard coating film. According to clause 10,
(c) is a method of producing an antibacterial hard coating film further comprising irradiating ultraviolet rays. According to clause 11,
The ultraviolet ray is irradiated at a light amount of 600 to 800 mJ/cm ^2. A method of producing an antibacterial hard coating film.

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