KR20210118549A - Light blocking film for optical device and manufacturing method therof - Google Patents

Abstract

According to one aspect of the present invention, provided is a light blocking film for an optical device. The light blocking film for an optical device includes a substrate comprising a synthetic resin film, and a light blocking layer formed on at least one surface of the substrate. The light blocking layer is a cured coating solution containing inorganic particles having gloss removal properties, a black filler having a particle size smaller than that of inorganic particles and having light blocking properties, a binder resin, a dispersant and a solvent. The black filler may include two types of black fillers having different conductivity.

Description

Light blocking film for optical devices and manufacturing method thereof

The present application relates to a light blocking film for an optical device and a manufacturing method thereof.

Recently, many compact cameras and digital video cameras that are easy to carry anywhere and can be used at any time have been released on the market, and more and more high-performance compact cameras and digital video cameras are required. As such optical devices, particularly compact cameras and digital cameras, have improved in performance, there is a demand for higher performance in accessory materials constituting them, for example, shutters.

When a light blocking film having a light blocking layer is used as one of the shutter components, friction occurs on the surface of the light blocking layer of the light blocking film when the shutter is opened and closed, so it is necessary to reduce the frictional resistance of the light blocking layer surface. In order to reduce the friction, the irregularities should be reduced as much as possible by reducing the particle size of the surface of the light blocking layer.

On the other hand, it is known that the matting agent (inorganic particles) applied to the light-blocking layer coating solution to increase the matting property generally obtains a surface of the light-blocking layer with good matting properties as the particle size increases.

Numerous particles are attached to the surface of the light blocking film by a binder resin. Among the attached particles, there are a black filler (carbon black) and a matting agent, and the matting agent having the largest particle size is usually the matting agent.

Therefore, it is necessary to properly control the particle size of the matting agent to reduce the frictional resistance of the surface of the light blocking layer and to increase the matting property to sufficiently exhibit the performance of the light blocking layer.

In addition, in order to manufacture the light blocking film, it is necessary to maintain a constant time, that is, the pot life. Here, the pot life refers to the time during which the coating solution can be coated by curing drying without drying naturally while coating the front and rear surfaces of the light blocking film.

Korean Patent No. 1034105 ('Light-blocking film and manufacturing method thereof, registration date: May 02, 2011)

According to one embodiment of the present invention, there is provided a light blocking film for an optical device capable of coating a light blocking layer without naturally curing the coating liquid to maintain a constant pot life, and a method for manufacturing the same.

In addition, according to an embodiment of the present invention, light for optical devices can increase the matting property by causing diffuse reflection on the surface of the light blocking layer, and reduce the particle size of the matting agent to reduce the frictional resistance on the surface of the light blocking layer A barrier film and a method for preparing the same are provided.

According to one embodiment of the present invention, in a light blocking film for an optical device, comprising: a substrate including a synthetic resin film; and a light blocking layer formed on at least one surface of the substrate, wherein the light blocking layer is luster removed Inorganic particles having a property, a black filler having a particle size smaller than the inorganic particles and having light-shielding properties, a binder resin, a dispersing agent and a solvent are cured coating liquid, the black filler is two types of black fillers having different conductivity It provides a light blocking film for an optical device comprising a.

According to an embodiment of the present invention, a drying inhibitor is further added to the coating liquid, and the added drying inhibitor may include 1 to 15 wt% of the coating liquid.

According to an embodiment of the present invention, a curing catalyst for increasing the reactivity between the main agent of the binder resin and the curing agent may be further added to the coating solution. The curing catalyst may be a bismuth-based catalyst, and the added drying inhibitor may be acetylacetone.

According to an embodiment of the present invention, the inorganic particles may have an irregular particle size by pulverization, thereby causing diffuse reflection on the surface of the light blocking layer.

According to an embodiment of the present invention, in a method of manufacturing a light blocking film for an optical device, the steps of preparing a coating solution and coating the prepared coating solution on at least one surface of a substrate including a synthetic resin film and curing the coating solution coated on the substrate to form a light blocking layer, wherein the light blocking layer includes inorganic particles having gloss removal properties, black particles having a smaller particle diameter than the inorganic particles and having light blocking properties. A coating liquid containing a filler, a binder resin, a dispersant and a solvent is cured, and a drying inhibitor and a curing catalyst for increasing the reactivity between the main agent of the binder resin and the curing agent are further added to the coating liquid, and the black filler, It provides a method for manufacturing a light blocking film for optical devices, comprising two types of black fillers having different electrical conductivity, wherein the inorganic particles have irregular particle sizes by pulverization, thereby causing diffuse reflection on the surface of the light blocking layer.

According to an embodiment of the present invention, the preparing of the coating solution includes: stabilizing the coating solution by having a predetermined storage time; and shaking and stirring the stabilized coating solution for a predetermined period of time.

According to one embodiment of the present invention, by adding an appropriate amount of a natural drying inhibitor to the coating solution of the light blocking layer, the pot life is maintained for a certain period of time, so that the coating solution is not naturally dried and the light blocking layer can be coated. That is, when the natural drying time of the light blocking layer is fast, the surface drying occurs instantaneously even during the coating of the light blocking layer on the polyethylene terephthalate (PET) film, so that the light blocking layer coating is uneven and layering can be solved.

In addition, according to one embodiment of the present invention, by using a mixture of two types of black fillers having different electrical conductivity, electrical conductivity and light blocking properties can be secured at the same time, and dispersion compared to the case of using only black filler with high conductivity You can increase your stature. In addition, since electrical conductivity and light blocking properties can be mixed and used as much as desired, compared to the case of matching electrical conductivity and light blocking properties using a single black filler, there is an advantage in that the total content of black filler added in the preparation process can be reduced. .

In addition, according to one embodiment of the present invention, the matting agent (inorganic particles) of the light blocking layer can have an irregular particle size through pulverization, thereby causing diffuse reflection on the surface of the light blocking layer to increase the matting property (that is, , can lower the surface reflectance), and reduce the particle size of the matting agent to reduce the frictional resistance of the light blocking layer surface.

According to an embodiment of the present invention, the step of preparing the coating solution may further include heating the coating solution for a predetermined time during the storage time.

1 is a view showing a light blocking film according to an embodiment of the present invention.
2 is a view showing a coating apparatus for a light blocking film according to an embodiment of the present invention.
3 is an exemplary view showing a crusher cutter for crushing inorganic particles (matting agent) according to an embodiment of the present invention.
4 is a flowchart illustrating a method of manufacturing a light blocking film for an optical device according to an embodiment of the present invention.
5 is a diagram illustrating a shaking device according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiment of the present invention may be modified in various other forms, and the scope of the present invention is not limited only to the embodiments described below. The shapes and sizes of elements in the drawings may be exaggerated for clearer description, and elements indicated by the same reference numerals in the drawings are the same elements.

1 is a view showing a light blocking film 100 according to an embodiment of the present invention.

As shown in FIG. 1 , the light blocking film 100 according to an embodiment of the present invention includes a substrate 110 including a synthetic resin film, and a light blocking layer 120 formed on at least one surface of the substrate 110 . ) may be included. Although the light blocking layer 120 formed on one surface of the substrate 110 is illustrated in FIG. 1 , of course, it may also be formed on the other surface of the substrate 110 .

The above-described light blocking layer 120 includes inorganic particles 121 having gloss removal properties, black filler 123 having a smaller particle diameter than inorganic particles and light blocking properties, other binder resins, dispersants and solvents 122 . Since the coating liquid is cured, an anti-drying agent may be further added to the coating liquid. The added anti-drying agent serves to prevent the surface of the coating solution from being naturally dried and cured for a certain period of time.

In addition, the drying inhibitor described above may contain 1 to 15% by weight of the coating solution, which can delay natural drying by 2 to 3 hours compared to the case where the drying inhibitor is not added, and such drying prevention delay time is suitable for mass production of a light blocking film using the micro-gravure equipment 200 of FIG. 2 to be described later.

Meanwhile, a heat curing catalyst for increasing the reactivity between the main agent of the binder resin and the curing agent may be further added to the coating solution.

In addition, the inorganic particles can increase the matting property by causing diffuse reflection on the surface of the light blocking layer 120 by reducing the average particle size and having an irregular particle size by pulverizing the particle size of the preset size, and the average particle size is increased. Due to the small size, the frictional resistance of the surface of the light blocking layer 120 may be reduced.

Specifically, as the substrate 110, a polyethylene terephthalate (PET) film is suitable, and a synthetic resin film containing a black pigment such as carbon black or other pigment is preferably used.

In the present invention, when manufacturing a light blocking film for optical devices, acetylacetone that prevents the surface of the light blocking layer coating solution from drying naturally is added, so that the surface of the light blocking layer coating solution is natural when left or used. It prevents drying out for some time.

2 is a view showing a coating apparatus for a light blocking film according to an embodiment of the present invention, and shows the micro-gravure equipment 200 by way of example.

As shown in FIG. 2 , the light blocking layer coating solution 206 is applied to the gravure roller 204 of the micro gravure equipment 200 by adding acetylacetone to the light blocking layer coating solution to prevent natural drying of the surface of the coating solution. The supply tray (TRAY, 207) and the gravure roller 204 prevent natural drying of the surface of the light blocking layer coating solution 206 for a certain period of time (pot life), so supplying the coating solution and coating on the substrate 110 work goes smoothly.

When acetylacetone is mixed with the coating solution 206 of the light blocking layer, the surface of the light blocking layer 120 is prevented from drying naturally for a certain period of time. That is, the surface of the light blocking layer coating solution 206 is naturally dried in the tray 207 at the lower end of the gravure roller 204 as it facilitates the formation of the light blocking layer 120 after coating and the surface drying occurs quickly. It prevents the development and also eliminates the natural drying of the surface of the light blocking layer coating solution in the gravure roller 204 .

When acetylacetone is applied to the light blocking layer coating solution, the surface of the light blocking layer coating solution is not dried naturally for a certain period of time, so the operation of the micro gravure equipment 200 becomes smooth. In addition, even when the light blocking layer coating liquid 206 applied on the surface of the gravure roller 204 is transferred onto the polyethylene terephthalate (PET) film 201, the surface naturally dries in an instant, so that the light blocking layer coating surface on the film is uneven. It improves the problem of being coated with layers.

On the other hand, undescribed reference numeral 201 in FIG. 2 is a coating film, 202 is a tension control roller, 203 is a doctor blade, 205 is a light blocking layer coating solution inlet, 208 is a light blocking layer coating solution outlet, D is a coating film is the direction of movement.

On the other hand, a bismuth series is used as a heat curing catalyst to increase the reactivity between the main material of the binder resin and the curing agent and increase the curing speed. Tin-based may be considered, but tin-based is not recommended as it is a prohibited substance in Korea and abroad.

The above-described surface drying inhibitor, acetylacetone, may include 1 to 15 wt% of the total amount of the light blocking layer coating solution 206 .

In addition, it is recommended to make the coating of the light blocking layer 120 easy by containing a lot of a curing agent having a lower viscosity than the main agent in order for acetylacetone, which is an agent to prevent natural drying of the surface, in the light blocking layer coating solution 206 to exhibit its performance. do. For this purpose, the curing agent ratio is preferably contained in an amount of 50% by weight or more relative to the main ingredient.

If a large amount of a main agent having a higher viscosity than a curing agent is added as a binder resin, the viscosity will increase, making it difficult for the natural drying inhibitor, acetylacetone, to exhibit its performance. When the surface natural drying of the coating liquid occurs, the coating is made as a layer occurs because surface drying occurs even at the moment of coating on the film with the gravure roller 204 in the micro gravure equipment 200 . In order to prevent this, it is necessary to increase the content of the curing agent having a lower viscosity than the main agent and lower the ratio of the main material. As a curing agent for the binder resin, 24A-100, 22A-75PX, 21S-75E of Asahi Chemical was used as a burette type, and T5651, a polycarbonate polyol of Asahi Chemical was used as the main agent.

On the other hand, in general, it is known that the matting agent 121 applied to increase the matting property used in the light blocking layer coating liquid 206 obtains a surface of the light blocking layer with good matting properties as the particle size increases. When a matting agent with a large particle size is used in a light blocking film for optical devices, the matting property is increased, but when a light blocking film with a light blocking layer is used as one of the shutter components, the light blocking layer of the light blocking film Since surface friction is further generated due to the large irregularities caused by the matting agent particles, the surface frictional resistance of the light blocking film 100 may be increased and performance such as sliding properties may be deteriorated. In addition, when the particle size of the matting agent is large, the probability of causing a problem that the matting agent is detached from the light blocking film 100 by friction increases.

On the other hand, if the particle size of the matting agent is reduced in order to reduce surface friction in the light blocking layer 120, the surface friction is reduced, but the matting property of the surface of the light blocking layer 120 is deteriorated, so that the matting performance of the light blocking film cannot be properly maintained. do.

In addition, if the particle size of the matting agent added to the light blocking layer coating liquid 206 is large, the matting agent attached to the light blocking layer 120 of the light blocking film 100 when punched using a mold with the light blocking film There may be a tendency to decrease the thickness of the light blocking film 100 by being pressed by the punching punch of the mold.

The above-mentioned inorganic particles (matting agent) are made of silica, and preferably contained in an amount of 0.5 wt% to 5 wt% as TS-100 of Evonik. The average particle size of the matting agent is about 2.5 μm to 10 μm.

In the conventional design, when the particle size of the matting agent is set to be large in order to increase the surface matting property of the light blocking layer 120, the frictional force on the surface of the light blocking layer increases, making it difficult to maintain performance such as sliding properties.

In the present invention, unlike the particles used as a matting agent in a conventional light blocking film, the matting agent is pulverized and applied to devise a method for properly realizing the matting performance of the light blocking film light blocking layer despite the decrease in the size of the matting agent particle size did it

That is, in order to sufficiently exhibit the performance of the light blocking layer in the light blocking film, at the same time reduce the frictional resistance of the light blocking layer surface, and further improve the problem of the matting agent falling off the coated light blocking layer surface, the matting agent particles are crushed through pulverization. Reduce the size.

If the particle size of the matting agent is reduced, the particle size becomes smaller, so it is a self-evident fact that the particles are better adhered to the larger sizes by the binder resin applied to the surface of the light blocking layer. In the case of reducing the particle size of the matting agent, the matting property is deteriorated, and in order to prevent this, each matting agent is made smaller by grinding the matting agent and made into more arbitrary various shapes and particle sizes.

Then, when light is incident on the surface of the light blocking layer, it causes diffuse reflection by the irregular light blocking layer surface made by the matting agent, and consequently the surface reflectance is lowered. A grinding method for making the matting agent particles into more arbitrary shapes and various particle sizes is to grind the matting agent for a certain period of time using a cutter (see 300 in FIG. 3 ) rotating at high speed. Then, while reducing the matting agent particles, it is possible to maintain similar matting properties as when the matting agent particle size is not reduced.

Meanwhile, the black filler 122 may have an average particle diameter smaller than that of the matting agent 121 and may have light blocking properties.

The black filler 122 is used to provide light-shielding properties by coloring the binder resin, dispersant, and liquid lubricant in black, and at the same time to impart conductivity to prevent the light blocking film 100 from being charged by static electricity due to friction or the like. will be.

The black filler 122 may include carbon black having relatively high conductivity and carbon black having relatively low conductivity, and the average particle diameter of carbon black having relatively high conductivity and carbon black having relatively low conductivity is sufficient for light blocking and low conductivity. In order to obtain a surface resistance, about 0.05 μm to 2 μm is preferable. Carbon black with relatively high conductivity is KETJENBLACK 300 or 600 series, and for carbon black with relatively low conductivity, PRINTEX L or HIBLACK 40B2 of Orion Engineered Carbons is used.

That is, the high-conductivity black filler contributes to electrical conduction on the surface of the light-blocking layer to increase the electrical conductivity on the surface of the light-blocking layer, while the low-conductivity black filler mainly blocks light on the surface of the light-blocking layer. Therefore, according to one embodiment of the present invention, there is an advantage in that electrical conductivity and light blocking properties can be simultaneously secured by mixing and using two types of black fillers having different conductivity.

In addition, black filler with high conductivity does not have good dispersibility when blended with binder resin, so it takes considerable effort and time to disperse, whereas black filler with low conductivity has relatively good dispersibility when blended with binder resin, so it takes a lot of effort to disperse. Therefore, there is an advantage in that the dispersibility of carbon black can also be improved compared to the case where only a black filler having high conductivity is used.

On the other hand, a dispersing agent is used that is advantageous for dispersing a matting agent and carbon black. As a dispersant, BASF's Efka® PU 4009, Efka® PU 4015, and Efka® PX 4320 are used alone or in combination of two or more.

The main solvent is preferably toluene, MEK, ethyl acetate, or butyl acetate, either alone or in combination, and preferably toluene is used.

Co-solvents include acetonitrile (ACETONITRILE), acrylonitrile (ACLONITRILE), nitromethane (NITROMETHANE), dioxane (DIOXANE), and pyridine (PYRIDINE). It may be used alone or in combination of two or more. And, aluminum nitrate 9hydrate (ALUMINNIUM NITRATE NONAHYDRATE) is added to make carbon black and matting agent better dispersed in the main and auxiliary solvents.

After sealing the light-shielding layer coating solution prepared from the first stage of stirring the light-shielding layer coating solution to the last step of stirring, it is stored (leaved) 1 to 4 times at room temperature within the range of 1 hour to 168 hours (referred to as the 'storage period'). ) is placed

The storage period is a period in which the air bubbles contained in the light-shielding layer coating solution are removed and stabilized when the coating solution is stored before completing the preparation. If the bubbles contained in the coating solution are removed and the coating solution is stabilized, it is possible to prevent the surface of the coating solution from drying naturally for a certain period of time while leaving or using the light-shielding layer coating solution in which the crude solution is completed. In addition, during the storage period of the coating solution, it can be stored while heating the coating solution at 30~70℃ for 1~30 hours.

It takes time to store and to shake (shaking) the crude liquid. For shaking, place a stirrer on the shaking device and shake for 1 to 24 hours. The shaking device is as shown in FIG. 5 . In this way, the agitation of the coating solution becomes smoother, and the adhesion between the polyethylene terephthalate (PET) film and the coating solution after coating the coating solution on the polyethylene terephthalate (PET) film can be improved. In addition, the light blocking film thus completed may have improved optical performance and increased reliability at the same time.

A shaking device 500 is shown in FIG. 5 .

As shown in FIG. 5 , the shaking device 500 includes the first base member 510 of the flat plate and the second base member 530 via the elastic members 521 to 524 so that the second base member 530 vibrates up and down. A plurality of elastic members 521 to 524 for fixing the member 530 on the first base member 510 , and a support member 540 fixed to the second base member 530 to accommodate the stirring barrel 10 . may be included.

It should be noted that the above-described elastic members 521 to 524 may be, for example, springs, but are not necessarily limited thereto.

In addition, the above-described support member 540 is fixed on the second base member 530 having the same diameter as the circular upper ring 541, the upper ring 541 having a slightly larger diameter than the diameter of the stirring barrel (10). a circular lower ring 542, and a plurality of connecting members 543 installed with a predetermined interval between the upper ring 541 and the lower ring 542 to connect the upper ring 541 and the lower ring 542 It may be composed of

The shaking device 500 described above is shaken by the elastic members 521 to 524 , and the coating liquid inside the stirring vessel 10 is also shaken by the shaking generated so that the coating liquid may be stirred. The shaking device 500 may be loaded in a vehicle trunk or may be fixedly installed in the vehicle trunk.

Immediately after wet coating of the light blocking film 100, the drying temperature is usually 60 ~ 130 ℃ hot air, and heat drying is performed so that the light blocking layer 120 of the light blocking film 100 is properly formed. When the light blocking film 100 is completed, the finished film is obtained when it is aged in an aging room for 1 to 3 days at a temperature between 40 and 60°C.

In the coating solution of the light blocking film 100 , the wetting agent uses a quick-drying property. Acetylacetone, which is used as an anti-drying agent on the surface of the light blocking layer coating solution, is applied in an amount of 1 to 15% by weight based on the total amount of the coating solution.

Examples of the present invention - Preparation of light blocking film for optical devices of the present invention

(1) Carbon black, dispersant, lubricant, wetting agent, acetylacetone, and toluene as a coating solution for light blocking film are mixed with stirring for 30 minutes and dispersed for 2-3 hours with a basket mill.

(2) A 25 µm transparent polyethylene terephthalate (PET) film is prepared as a film.

(3) Mix the matting agent, acetonitrile, and aluminum nitrate 9 hydrate (ALUMINNIUM NITRATE NONAHYDRATE) with the (milled) liquid made in (1) and stir in a motor stirrer at 400rpm for 10 minutes.

(4) Add a binder resin curing agent to the liquid prepared in (3) and stir at 400rpm for 30 minutes in a motor stirrer.

(5) Properly seal in the liquid prepared up to (4) and store for 3 hours.

(6) Add the main agent (of the binder resin) and the heat curing catalyst to the liquid prepared in (5), and stir at 400 rpm for 30 minutes with a motor stirrer.

(7) Properly seal the liquid prepared in (6) and shake for 3 hours.

(8) Light blocking film When the light blocking layer liquid is completed, it is coated on the prepared polyethylene terephthalate (PET) film with a bar coater to a thickness of 7~8㎛, and then heated and dried in a drying furnace at 100~120℃ for 2 minutes to achieve optical performance. check the In particular, measure the glossiness to check the glossiness of the surface of the light blocking layer 120 and measure and record how many hours the surface of the light blocking layer coating solution naturally dried after completion of the preparation of the light blocking layer coating solution.

(9) Composition ratio of coating solution of light blocking film

1) Binder resin curing agent: Asahi Chemical burette resin 60g

2) Binder resin subject: 15g of Asahi Chemical polycarbonate polyol

3) Dispersant: BASF Efka® PX 4320 25g

4) Lubricant: Efka® SL 3030 1g

5) Matting agent: Evonik's TS-100 2.5g

6) Carbon Black: KETJENBLACK EC600JD 5g

7) Carbon Black: PRINTEX L 5g

8) Main solvent: Daejeonghwageum toluene 90g

9) Auxiliary solvent: Daejeonghwageum acetonitrile 60g + aluminum nitrate 9 hydrate 0.8g

10) Wetting agent: BYK-399 2g

11) Natural drying inhibitor: Daejeonghwageum Acetylacetone 16g

12) Curing catalyst: Seho Tech ES-100 4.2g

2. Comparative Example - Preparation of light blocking film for conventional optical devices

(1) Carbon black, toluene, and MEK as a coating solution for the light blocking film are mixed with stirring for 30 minutes and dispersed for 2-3 hours with a basket mill.

(2) A 25 µm transparent polyethylene terephthalate (PET) film is prepared as a film.

(3) Mix matting agent, toluene and MEK with the (milled) liquid made in (1) and stir at 400rpm for 10 minutes in a motor stirrer.

(4) Add the main agent (A804) of the binder resin to the liquid prepared in (3) and stir for 30 minutes at 400 rpm in a motor stirrer.

(5) Add curing agent (DN980) and solid lubricant to the liquid prepared in (4) and stir at 400rpm for 30 minutes in a motor stirrer.

(6) Light blocking film When the light blocking layer liquid is completed, coat the prepared polyethylene terephthalate (PET) film to a thickness of 7-8㎛ with a bar coater and dry it in a drying furnace at 100~120℃ for 2 minutes to improve optical performance. check In particular, measure the glossiness and measure and record how many hours the surface of the light blocking layer coating solution dried after the preparation of the light blocking layer coating solution was completed.

(7) Composition ratio of coating solution of light blocking film

1) Acrylic polyol (50% solids) 92g (Acridic A804: DIC product)

2) Isocyanate (solid content 75%) 25g (Burnock DN980: DIC product)

3) Carbon Black 16.3g (Vulcan XC-72: Cabot Company)

4) Lubricant 16.3g (average particle diameter 8.5 ㎛) (Cerithust 3620: Hextosa)

5) 2.6g matting agent

6) methyl ethyl ketone 60 g

7) 40 g of toluene

3. Test method

(1) Test to confirm surface dry condition of coating liquid (Test method 1)

After the completion of each of the coating liquid preparations of the Comparative Examples and the Examples of the present invention 5 times, the surface dry state was investigated for each time period, the number of hours the surface drying of the coating liquid took place was measured, and the time was recorded.

(2) Coating liquid surface glossiness measurement test (Test method 2)

After completion of each of the coating solutions of Comparative Examples and Examples of the present invention 5 times, each coating solution was coated and dried on a film, and the glossiness of the surface was measured with a gloss meter, and the value was recorded.

(3) Coating liquid surface optical density measurement test (Test method 3)

After completing each of the coating solutions of Comparative Examples and Examples of the present invention 5 times, each coating solution was coated and dried on a film, and the optical density of the surface was measured with an optical densitometer, and the value was recorded.

4. Test results

As shown in Table 1, in Experimental Method 1, as a result of coating the light blocking layer, it can be seen that the case of the present Example exhibits relatively superior properties compared to the Comparative Example. Experimental methods 2 and 3 show similar characteristics when compared with this Example and Comparative Example. Looking at the test results of Experimental Method 3, it can be seen that the Example has a similar optical density even though the carbon content is smaller than that of the Comparative Example.

Next, the coating solution may be coated on at least one surface of the prepared substrate. The coating can be coated to a thickness of 7-8 μm using a bar coater.

The coating solution described above includes inorganic particles having gloss removal properties, black filler having an average particle diameter smaller than the particle diameter of the inorganic particles and having light blocking properties, a binder resin, a dispersing agent, and a solvent. As described above, the inorganic particles having gloss removal properties may be a matting agent pulverized with a high-speed rotating cutter.

Thereafter, the light blocking layer may be formed by curing the coating solution coated on the substrate. For curing, it may be dried for 1 to 3 minutes in a drying furnace at 60 to 130°C.

As described above, according to one embodiment of the present invention, by adding an appropriate amount of an anti-drying agent to the coating solution of the light blocking layer, the pot life is maintained for a certain period of time, so that the coating solution is heat-cured without natural drying. coating is possible. That is, if the natural drying time of the surface of the coating solution is fast, natural drying occurs on the surface instantaneously even during the coating of the light blocking layer on the polyethylene terephthalate (PET) film, so the problem of uneven and layered light blocking layer can be solved. .

In addition, according to one embodiment of the present invention, the matting agent (inorganic particles) of the light blocking layer can have an irregular particle size through pulverization, thereby causing diffuse reflection on the surface of the light blocking layer to increase the matting property (that is, , can lower the surface reflectance), and reduce the particle size of the matting agent to reduce the frictional resistance of the light blocking layer surface.

Meanwhile, FIG. 4 is a flowchart illustrating a method of manufacturing a light blocking film for an optical device according to an embodiment of the present invention. For simplification of the invention, descriptions of parts overlapping those described with reference to FIGS. 1 to 3 will be omitted.

As shown in FIG. 4 , the method of manufacturing a light blocking film for an optical device according to an embodiment of the present invention may be started by first preparing a coating solution ( S401 ).

The manufacturing process of the coating solution is the same as described above, and the coating solution includes inorganic particles 121 , black filler 123 having a smaller particle diameter than inorganic particles and light blocking properties, other binder resins, dispersants, and solvents 122 . By doing so, an anti-drying agent may be further added to the coating solution, and the black filler 123 is used by mixing two types of black fillers having different conductivity as described above. The added anti-drying agent serves to prevent the surface of the coating solution from being naturally dried and cured for a certain period of time.

In particular, according to an embodiment of the present invention, in the step of preparing the coating solution, the method may further include stabilizing by removing air bubbles in the coating solution by having a predetermined storage time or heating and storage time and shaking time. is as described above.

In addition, the above-described anti-drying agent may include 1 to 15% by weight of the coating solution. Meanwhile, a curing catalyst for increasing the reactivity between the main material of the binder resin and the curing agent may be further added to the coating solution.

And, the inorganic particles can have an irregular particle size by pulverizing the particle size of a preset size, thereby causing diffuse reflection on the surface of the light blocking layer 120 to increase the matting property, and by reducing the particle size by pulverization As described above, the frictional resistance of the surface of the light blocking layer 120 can be reduced.

Next, at least one surface of the substrate may be coated with the prepared coating solution (S402). The coating can be coated to a thickness of 7-8 μm using a bar coater or micro-gravure equipment.

Thereafter, the light blocking layer may be formed by curing the coating solution coated on the substrate (S403).

As described above, according to one embodiment of the present invention, by adding an appropriate amount of a natural drying inhibitor to the coating solution of the light blocking layer, the pot life is maintained for a certain period of time so that the surface of the coating solution during micro-gravure coating is not naturally cured. It is possible to coat the light blocking layer by heat drying without In other words, if the natural drying time of the surface of the coating solution is fast, natural drying of the surface of the coating solution occurs instantaneously even during the coating of the light blocking layer on the polyethylene terephthalate (PET) film, which solves the problem of uneven and layered light blocking layer coating. can

In addition, according to one embodiment of the present invention, the matting agent of the light blocking layer can have an irregular particle size through pulverization, thereby causing diffuse reflection on the surface of the light blocking layer to increase the matting property (that is, reducing the surface reflectance) can be lowered), and by reducing the particle size of the matting agent, the frictional resistance of the surface of the light blocking layer can be reduced.

The present invention is not limited by the above-described embodiments and the accompanying drawings. It is intended to limit the scope of rights by the appended claims, and it is to those skilled in the art that various forms of substitution, modification and change can be made without departing from the technical spirit of the present invention described in the claims. it will be self explanatory

10: stirrer
100: light blocking film
110: substrate
120: light blocking layer
121: inorganic particles
122: mixing of binder resin, liquid lubricant, dispersant and solvent
123: black filler
200: micro gravure equipment
201: film for coating
202: tension adjustment roller
203: Doctor Blade
204: gravure roller
205: light blocking layer coating liquid inlet
206: coating liquid
207: coating liquid tray (TRAY)
208: light blocking layer coating liquid outlet
300: grinder
500: shaking device
510: first base member
521 to 524: elastic member
530: second base member
540: support member
541: upper ring
542: lower ring
543: connection member

Claims (8)

In the light blocking film for an optical device,
A base material comprising a synthetic resin film, and
a light blocking layer formed on at least one surface of the substrate;
The light blocking layer,
A coating solution containing inorganic particles having gloss removal properties, a black filler having a smaller particle diameter than the inorganic particles and light blocking properties, a binder resin, a dispersing agent, and a solvent is cured,
The said black filler contains two types of black fillers from which electroconductivity differs, The light-blocking film for optical devices.
According to claim 1,
A drying inhibitor is further added to the coating solution,
The added anti-drying agent,
A light blocking film for optical devices, comprising 1 to 15% by weight of the coating solution.
According to claim 1,
In the coating liquid,
A curing catalyst is further added to increase the reactivity between the main material of the binder resin and the curing agent,
The curing catalyst is a bismuth-based catalyst, a light blocking film for optical devices.
3. The method of claim 2,
The added anti-drying agent,
Acetylacetone, a light blocking film for optical instruments.
According to claim 1,
The inorganic particles are
A light blocking film for optical devices, which causes diffuse reflection on the surface of the light blocking layer by having an irregular particle size by grinding.
A method for manufacturing a light blocking film for an optical device, the method comprising:
preparing a coating solution;
coating the coating solution prepared on at least one surface of a substrate including a synthetic resin film;
and curing the coating solution coated on the substrate to form a light blocking layer,
The light blocking layer,
A coating solution containing inorganic particles having gloss removal properties, a black filler having a smaller particle diameter than the inorganic particles and light blocking properties, a binder resin, a dispersing agent, and a solvent is cured,
A curing catalyst is further added to the coating liquid to increase the reactivity between the main agent of the binder resin and the curing agent,
The black filler includes two types of black fillers having different electrical conductivity,
The inorganic particles have an irregular particle size to cause diffuse reflection on the surface of the light blocking layer, a method for manufacturing a light blocking film for optical devices.
7. The method of claim 6,
The preparing of the coating solution may include stabilizing the coating solution by having a predetermined storage time; and
A method of manufacturing a light blocking film for optical devices, including; shaking and stirring the stabilized coating solution for a predetermined time.
8. The method of claim 7,
The step of preparing the coating liquid,
Method of manufacturing a light blocking film for optical devices further comprising; heating the coating solution for a predetermined time during the storage time.

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