KR102334478B1 - The manufacturing method of the Optical layer comprising the thermochromic layer having good optical characteristic controlling photonic evaporation and photonic sintering conditions - Google Patents

Abstract

The present invention is a substrate; an optical laminate that is formed on the substrate and includes a thermochromic layer comprising vanadium oxide particles, an adhesive strength between the thermochromic layer and the substrate is 50 N/m or more, and the thermochromic layer is controlled to have a specific void area ratio sieve, and the laminate has excellent visible light transmittance and infrared transmittance.

Description

The manufacturing method of the optical layer comprising the thermochromic layer having good optical characteristic controlling photonic evaporation and photonic sintering conditions

The present invention relates to a method of manufacturing an optical laminate including a thermochromic layer having excellent optical properties by controlling photoevaporation and photosintering conditions.

As the disadvantages of conventional coal, petroleum, or nuclear energy sources are highlighted, the need for new alternative energy sources is growing. However, it is equally important to control energy consumption. In fact, more than 60% of household energy consumption is used for heating and cooling costs. In particular, energy consumed through windows in general houses and buildings reaches 24%. Therefore, in order to reduce the energy consumed through the window, various efforts are being made from a method of adjusting the size of the window to a method of installing a high-insulation window glass.

For example, thermochromic glass that controls energy input by controlling infrared transmittance by coating a thermochromic layer having thermochromism on glass is being studied.

Thermochromism is a phenomenon in which the color of an oxide or sulfide of a transition metal is reversibly changed at a transition temperature (or critical temperature). It is possible to manufacture thermochromic glass in which near-infrared rays and infrared rays are blocked so that the room temperature does not rise. By using this characteristic, it is possible to block near-infrared light at high temperatures in summer to suppress the rise in indoor temperature, and to bring in light energy from the outside at low temperatures in winter. If such thermochromic glass is used for the windows of buildings, a great energy saving effect can be expected.

Materials exhibiting the thermochromic effect include oxides or sulfides of various transition metals. Among them, studies on the use of _{vanadium dioxide (VO 2 ) having a transition temperature (phase transition temperature) of 68°C are mainly conducted.}

Korean Patent No. 10-1286170 discloses a technique for coating vanadium dioxide on a glass plate using sputtering deposition, and Japanese Patent Laid-Open No. 2007-22838 describes a technique for coating vanadium dioxide on a glass plate using a CVD process. has been However, conventional methods of coating vanadium dioxide on a glass plate, such as sputtering deposition or CVD process, all require a subsequent heat treatment process, requiring a long process time, and there is a problem in that it is difficult to produce a product with a large area. In addition, due to the high-temperature heat treatment process, there was a great limitation in the material selection of the substrate to be coated with vanadium dioxide.

Meanwhile, Japanese Patent Laid-Open No. 2016-188939 discloses a method of dispersing vanadium dioxide-containing fine particles in a binder resin, and coating the dispersion on a polymer substrate to form an optical function layer. However, it is difficult for the particles to be uniformly dispersed in the polymer resin, and since the sintering process is not performed, the crystallinity is poor, the light blocking effect is not sufficient, and the light transmission property is inhibited by the polymer resin.

Republic of Korea Patent No. 10-1286170 Japanese Patent Application Laid-Open No. 2007-22838 Japanese Patent Laid-Open No. 2016-188939

In order to solve the above problems, an object of the present invention is to provide a method of manufacturing an optical laminate that can be manufactured in a large area through a simple manufacturing process and has optical properties such as controlled visible light and infrared transmittance.

In order to solve the above problems, the present invention is a substrate; and a method for manufacturing an optical laminate comprising a thermochromic layer formed on the substrate and including imaged vanadium clusters, the forming step of applying a solution containing vanadium oxide particles on the substrate to form an application layer ; A photo-evaporation step of irradiating light to remove organic matter from the coating layer; and photo-sintering the vanadium oxide particles included in the coating layer by irradiating light to prepare a thermochromic layer including vanadium oxide clusters.

According to the present invention, a large-area optical laminate can be manufactured with a simple manufacturing process, there is no limitation on the type of substrate on which the thermochromic layer is formed, and a method for manufacturing an optical laminate having controlled visible light and infrared transmittance is provided. can provide

1 is a view showing electron microscope images and appearances of optical laminates prepared in Examples 1, 2, Comparative Examples 1 and 2;
2 is a view showing electron microscope images and appearances of optical laminates prepared in Examples 1, 3, 4, 5, and Comparative Example 3;
3 is a view showing electron microscope images and appearance of the optical laminates prepared in Examples 6, 7, 2 and Comparative Example 4;
4 is a view showing electron microscope images and appearances of optical laminates prepared in Example 8, Example 2, Comparative Example 5, and Comparative Example 6;

The present invention is a substrate; and a thermochromic layer formed on the substrate and including an imaged vanadium cluster. As used herein, the term “vanadium oxide cluster” refers to an agglomerate formed by removing an organic solvent from a solution containing vanadium oxide particles, sintering, and causing coalescence between the vanadium oxide particles.

The method includes a forming step of applying a solution containing vanadium oxide particles on a substrate to form an application layer; A photo-evaporation step of irradiating light to remove organic matter from the coating layer; and a photo-sintering step of photo-sintering the vanadium oxide particles included in the coating layer by irradiating light to prepare a thermochromic layer including the vanadium oxide cluster. The manufacturing method may be particularly effective when forming a thermochromic layer on a substrate made of a heat-sensitive material such as a polymer film. In the manufacturing method, a thermochromic layer having controlled visible light transmittance and infrared transmission/blocking properties is formed on a substrate without physical deformation of the substrate by irradiating light in two steps (photoevaporation step and photo-sintering step). can be formed.

In the photoevaporation step, most organic materials are removed by irradiation with light, and in the photo-sintering step, adhesion between vanadium oxide particles occurs (neck growth) by light irradiation to form a vanadium oxide cluster.

* On the other hand, high-temperature heat is involved in these steps of photoevaporation and photosintering. Therefore, when the substrate is made of a heat-sensitive material such as a polymer film, specific conditions of the photoevaporation and photosintering step, for example, the type of light, applied voltage (output voltage), pulse width, number of pulses (repeated irradiation of light) number of times) and pulse interval (frequency) can be controlled to prepare a thermochromic layer having desired physical properties without physical deformation of the polymer film. For example, as the light, white light applied from a xenon lamp may be used, the voltage may be 1000 to 3000 V, the number of pulses may be 1 to 500 times, the pulse interval may be 1 to 10 Hz, and the pulse width may be 1 ms to 10 ms.

First, in the photoevaporation step, as the number of pulses increases, the total energy increases to effectively remove the solvent, but when the number of pulses is excessively high, the total energy increases and physical deformation of the polymer film may occur. The total energy is determined by the output voltage, pulse width, pulse interval, and number of pulses. The number of pulses may be, for example, 200 to 400 times, 250 to 350 times, or about 300 times.

As the pulse interval decreases, the process time may be reduced due to an increase in average power applied per second. The average power is determined by the output voltage, pulse width, and pulse interval. However, when the pulse interval is 1 Hz or more, evaporation of the solvent may be performed, and when the pulse interval is less than 1 Hz, the bed temperature rises rapidly, and physical deformation of the polymer film may occur.

In addition, as the output voltage increases, the organic material is effectively removed, but physical deformation of the polymer film may occur, and the appropriate voltage at which physical deformation does not occur may be in the range of 1000V to 1500V, 1100V to 1400V, or 1200V to 1300V.

In addition, as the output voltage increased, the concentration of organic matter (carbon or nitrogen) at the contact surface formed between the thermochromic layer and the substrate decreased, for example, the concentration of the organic material decreased sharply at 1200V, and the first organic matter removal occurred at 1100V.

On the other hand, the output voltage is related to the visible light transmittance and infrared transmittance of the laminate, and as the voltage increases, the physical deformation of the polymer film occurs and the visible light transmittance decreases. However, it falls due to crack formation of the thermochromic layer above 1400V.

The photosintering step is a step of transforming the specific light irradiation conditions in the photoevaporation step into photosintering conditions to be described later, and thus, the photoevaporation step and the photosintering step may be continuously performed.

The output voltage of light in the photosintering step may be higher than the output voltage of light in the photoevaporation step. In the photo-sintering step, the output voltage of light should be selected within a range in which deformation of the substrate does not occur at the same time that the vanadium oxide particles are sintered, for example, 1500V to 3000V, 1600 to 2500V, 1700V to 1800V, or about 1700V. can

In addition, the photo-evaporation step and the photos-sintering step are repeatedly irradiated with light with a constant pulse width, the number of repeated irradiation of light in the photos-sintering step may be less than or equal to the number of repetitions of light in the photo-evaporation step. In the photosintering step, as the number of irradiation increases, the spacing between vanadium oxide particles becomes narrower, so that vanadium oxide clusters may be formed. As the number of irradiation increases in the photosintering step, the visible light transmittance and infrared transmittance are improved, but when it exceeds a certain number of times, deformation of the substrate occurs and decreases. For example, the infrared transmittance is improved up to 200 times, and the visible light transmittance and infrared transmittance are deteriorated at 250 times or more. Accordingly, the number of irradiation in the photosintering step may be 50 to 300 times, 100 to 250 times, 150 to 200 times, or about 200 times may be appropriate.

In addition, the pulse width of light in the photosintering step may be smaller than the pulse width of light in the photoevaporation step. For example, the pulse width in the photoevaporation step may be 1 to 10ms, 2 to 8ms, or 3 to 5ms, and the pulse width in the photosintering step may be 0.1 to 5ms, 0.5 to 3ms, or 1 to 2ms.

In one example, the photoevaporation step and the photosintering step may be performed under an atmospheric atmosphere. In particular, in the photoevaporation step, the atmosphere is related to organic matter removal, for example, oxygen concentration in the bed acts as a major factor in organic matter removal. In particular, when the process is carried out in an inert atmosphere such as nitrogen or argon or in a vacuum atmosphere, most organic substances are not removed and the concentration of organic substances on the surface increases. The concentration of organic matter on the surface is related to the infrared transmittance. For example, the concentration of organic matter on the surface increases in the order of atmospheric atmosphere, inert atmosphere, and vacuum atmosphere, and the infrared transmittance falls in the order of atmospheric atmosphere, inert atmosphere, and vacuum atmosphere. .

In one example, the solution composition comprising vanadium oxide is vanadium oxide particles; menstruum; polymer dispersant; and a binder, wherein the polymer dispersant has a molecular weight of 10,000 to 360,000, and a viscosity of 1 to 100 cP, specifically 5 to 40 cP.

The molecular weight of the polymer dispersant that can be used in the present invention is 10,000 to 360,000, for example, 11,000 to 200,000, 12,000 to 100,000, or 15,000 to 70,000. When the molecular weight is within the above range, excellent dispersibility and viscosity necessary for applying the solution composition to the substrate can be secured.

The viscosity of the solution composition is from 1 to 100, for example from 1 to 40, from 5 to 30, from 10 to 25, or from 15 to 20. When the molecular weight as well as the viscosity of the polymer dispersant are adjusted within the above range, it is possible to satisfy the dispersibility of particles and the conditions of the application process.

In the solution composition, the content of the polymer dispersant is, for example, 1 to 10% by weight, specifically 2 to 8% by weight, 3 to 7% by weight based on the total weight of the solution composition. In order to control the visible light transmittance of the optical laminate and the crystallization of vanadium oxide, it is necessary to control the content of the dispersant within the above range.

The kind of the polymer dispersant, for example, an amine-based polymer dispersant such as polyethylene imine and polyvinyl pyrrolidone; Hydrocarbon-type polymer dispersing agent which has a carboxylic acid group in molecules, such as polyacrylic acid and carboxymethylcellulose; And at least one selected from the group consisting of a polymer dispersant having a polar group, such as polyvinyl alcohol, styrene-maleic acid copolymer, olefin-maleic acid copolymer, or a copolymer having a polyethylene imine moiety and a polyethylene oxide moiety in one molecule. .

In one embodiment, the polymer dispersing agent may be a water-soluble polymer, specifically an amine-based polymer, particularly polyvinylpyrrolidone (PVP). When PVP is used, an aqueous solvent can be used, which is environmentally friendly, so that environmental pollution can be minimized even in manufacturing a large-area optical laminate.

In the solution composition, the type of the binder is not particularly limited, but for example, a cellulose-based resin, polyvinyl chloride resin, polyvinyl alcohol-based resin, polyvinylpyrrolidone-based resin, acrylic resin, vinyl acetate-acrylic acid It is at least one selected from the group consisting of an ester copolymer resin, a butyral resin, an alkyd resin, an epoxy resin, a phenol resin, a rosin ester resin, a polyester resin, and a silicone resin.

The content of the binder is, for example, 0.1 to 3% by weight, specifically 0.2 to 2% by weight, 0.5 to 1.5% by weight based on the total weight of the solution composition. If the content of the binder exceeds 3% by weight, there is a fear that it may not be completely dissolved in the solvent, it may aggregate over time, and if it is less than 0.1% by weight, there is a fear that the adhesion with the substrate may decrease.

The type of the solvent is not particularly limited, but for example, water, a hydrocarbon-based solvent, a chlorinated hydrocarbon-based solvent, a cyclic ether-based solvent, a ketone-based solvent, an alcohol, a polyhydric alcohol-based solvent, an acetate-based solvent, a polyhydric alcohol at least one selected from the group consisting of an etheric solvent or a terpene-based solvent. An appropriate solvent may be selected depending on the polymer binder and dispersant used, but it is preferable to use a mixture of water and alcohol in consideration of environmental factors, dispersion characteristics, and drying time. Specifically, in consideration of wettability, it is preferable to use alcohol. The alcohol is not particularly limited, but an alcohol having a straight-chain alkyl group having 2 to 6 carbon atoms, for example, ethanol, propanol, or butanol may be used. Considering the drying time, it is preferable to use ethanol with a low boiling point.

At this time, the water and alcohol weight ratio, for example, 1: 0.5 to 1.5, specifically 1: 0.7 to 1.3, 1: can be used by mixing in a ratio of 0.8 to 1.2. When the water and alcohol weight ratio is controlled within the above range, the binder and the dispersant may be sufficiently dissolved, and an appropriate viscosity may be maintained.

The vanadium oxide particles may specifically include rutile-type vanadium dioxide (VO2) particles. The content of the vanadium dioxide particles is, for example, 1 to 50% by weight, for example, 5 to 40% by weight, 10 to 35% by weight, 15 to 30% by weight based on the total weight of the solution composition. In addition, the average diameter of the vanadium dioxide particles may be 1 to 1000 nm, for example, 10 to 500 nm, and when the vanadium dioxide particle content and average diameter are controlled within the above ranges, excellent thin film formation, uniform dispersibility and desired functionality can be obtained. .

The solution composition may be prepared by mixing vanadium dioxide particles, a polymer dispersing agent, and a binder in a solvent and uniformly stirring. More specifically, the method comprises the steps of preparing a polymer dispersant solution by mixing a polymer dispersant with a first solvent; preparing a binder solution by mixing a binder with a second solvent; and mixing the polymer dispersant solution and the binder solution with the vanadium dioxide particles to prepare an ink solution, and optionally or optionally further mixing a dopant.

Ultrasound may be applied to the solution for uniform dispersion of the solution prepared in each step. For example, the manufacturing method includes the steps of applying ultrasonic waves to the polymer dispersant solution; applying ultrasonic waves to the binder solution; The method may further include one or more steps from the group consisting of applying ultrasonic waves to the ink solution. Ultrasound application conditions are not particularly limited, but may be applied for 30 minutes to 2 hours at each step.

In the above step, the first solvent and the second solvent may be used without limitation as long as they are solvents capable of dissolving the dispersant and the binder, respectively, but, for example, the first solvent may be water and the second solvent may be ethanol.

In the method of manufacturing the optical laminate according to the present invention, the coating layer may be formed by applying at least one time or more, for example, it may be formed by applying one, two or more times. Specifically, in the case of forming the application layer in two applications, the forming step may include a first application step of applying a solution on a substrate; and a second application step of applying a solution on the application layer applied in the first application step.

In addition, the forming step is preferably performed by spin coating or spray coating. In an embodiment, spin coating may be performed by coating for a predetermined rotation speed and time to apply a solution. In the first application step, spin coating may be performed at a first rotation speed for a first rotation time, and in the second application step, spin coating may be performed at a second rotation speed for a second rotation time. The first and second rotation speeds are not particularly limited, but may be, for example, 1000 to 10000 rpm, 2000 to 9000 rpm, 3000 to 8000 rpm, or 4000 to 7000 rpm. In addition, the first and second rotation times may be 5 seconds to 50 seconds. The number of such applications may affect the size of clusters and the area ratio of pores in the thermochromic layer. For example, the cluster size increases due to the high sintering effect when applied once, but the area ratio of voids may be high due to the relatively low vanadium dioxide content. On the other hand, when applied twice, the formation of clusters is somewhat limited due to partial sintering of the particles, but the area ratio of pores is low due to the relatively high content of vanadium dioxide.

In addition, after each application step, a drying step may be performed, for example, the first application step, the first drying step, the second application step, and the second drying step are sequentially performed in that order, and the first and second The drying step may be performed, for example, within a range of 60 to 100°C.

The optical laminate manufactured according to the above method may realize the following physical properties.

Specifically, the vanadium oxide cluster may have a size of 20 to 250 nm, 40 to 220, or 50 to 200 nm.

In addition, the thermochromic layer may satisfy the following general formula (1).

[General formula 1]

1≤S(%)≤20

In the above formula, S represents the area ratio of the voids measured by analyzing the image taken of the upper surface of the sample by the image analysis device. In the thermochromic layer according to the present invention, when the surface in contact with the substrate is the contact surface and the opposite surface is the surface based on the cross section of the thermochromic layer, the term “upper surface” in General Formula 1 means the surface defined above .

The size of the cluster and the S value are related to each other. Specifically, when the size of the cluster increases, the S value decreases, and when the size of the cluster decreases, the S value increases. When each value is controlled within the above range, the visible light transmittance and Infrared transmission characteristics can be controlled.

For example, if the size of the cluster is less than 20 nm, for example, less than 30 nm, less than 40 nm, less than 50 nm, or less than 100 nm, it is difficult to control the infrared transmittance, and when it exceeds 250 nm, for example, 240 nm If it exceeds, exceeds 230 nm, exceeds 210 nm, exceeds 190 nm, or exceeds 150 nm, it is difficult to obtain visible light transmittance. Further, if the S value is less than 1%, for example, less than 2%, less than 3%, or less than 5%, it is difficult to obtain a visible light transmittance, and it is difficult to obtain a visible light transmittance, and it is more than 20%, more than 18%. , it is difficult to control the infrared transmittance when it exceeds 16%, or exceeds 15%. The S value can be measured by a known method using an image capturing apparatus such as an electron microscope (SEM) and an image analysis apparatus (S/W) that analyzes the same. For example, the image analysis apparatus may use software such as Image J that can determine the void by classifying the contrast ratio of the image photographed using an image pickup apparatus such as FE-SEM, and calculate the area thereof. The apparatus and software are known to the person skilled in the art. In addition, the size of the cluster can be measured by deriving a value as the average of the cluster maximum and minimum lengths according to the scale bar ratio on the image using an imaging device such as FE-SEM, and software such as Image J can be used. have.

As described above, the laminate is obtained by applying a solution composition on a substrate, removing most of the organic matter (eg, solvent) present in the solution composition through evaporation and sintering, and simultaneously sintering vanadium dioxide. Since it is manufactured, it is possible to provide a thermochromic layer having excellent thermochromic effect and optical properties. When the thermochromic layer is manufactured by using a conventional vapor phase method such as sputtering or CVD, desired thermochromic effect and optical properties cannot be obtained.

Specifically, the size and S value of the clusters in the thermochromic layer can be controlled through the contents of the dispersant and the binder in the solution, the average diameter of the particles, the thickness of the thin film, and specific conditions of light irradiation. The optical laminate according to the present application may form a thermochromic layer satisfying the above-described physical properties without limitation of the substrate by controlling specific conditions of evaporation and sintering, which will be described later.

In particular, since evaporation and sintering processes involve high-temperature heat, when a substrate vulnerable to heat is used, physical deformation of the substrate may be induced. For example, when a thermochromic layer is formed on a polymer film, cracks may be formed on the film by heat formed during evaporation and sintering. Therefore, when using a heat-sensitive substrate such as a polymer film, it is important to control the specific conditions of the evaporation and sintering process within the above range so that the thermochromic layer satisfies the above-described physical properties without physical deformation of the polymer film. .

The thickness of the thermochromic layer is not particularly limited, but may be 0.1 to 5 μm. Specifically, in the step of forming an application layer by applying a solution on a substrate, according to the number of coatings of the solution, 400 at one time of coating to 1000 nm, the thickness may be controlled within the range of 600 to 900 nm when coated twice.

_{The laminate has a maximum value (P max} ) of transmittance in the 400 to 800 nm region of 50% or more, 55% or more, 60% or more, or 65% or more, and transmittance in the 2000 to 3000 nm region at any temperature above the critical temperature. The minimum value OP _min may be 70% or less, 60% or less, specifically, 55% or less, 50% or less, or 40% or less. When the Pmax value is 50% or more, the visible light transmittance is high to secure a transparent view, and when the OPmin value is 65% or less, the infrared blocking effect is excellent.

In addition, the optical laminate may satisfy the condition of the following general formula (2), for example.

[General formula 2]

△IR=BP _min - Op _min ≥ 10 %

In Formula 2, BP _min represents the minimum value of transmittance at 2000 to 3000 nm at any temperature below the critical temperature, and OP _min represents the minimum value of transmittance at 2000 to 3000 nm at any temperature above the critical temperature. Here, the temperature below the critical temperature may be, for example, 20 to 30°C, specifically 25°C, and the temperature above the critical temperature may be, for example, 60 to 90°C, specifically 80°C. When the ΔIR value (%) is 10% or more, specifically 20% or more, 25% or more, 30% or more, or 35% or more, the effect regarding infrared blocking/transmission is excellent.

In addition, the adhesive strength of the thermochromic layer and the substrate is 50 N / m or more, for example, 60 N / m or more, 70 N / m or more, 100 N / m or more, 120 N / m or more, or 150 N / m or more It relates to an optical laminate. will be. The upper limit of the adhesive strength is not particularly limited, but is, for example, 250 N/m or less, or 300 N/m or less. As used herein, the term “adhesive strength” refers to a value calculated by measuring the resistance value generated when the blade separates the thermochromic layer from the substrate, and for specific conditions required for measurement, refer to Experimental Examples.

The type of the substrate may be selected from glass, quartz, or a polymer film. In particular, considering the utility of the flexible device, the substrate may be selected as a polymer film, and the type of the polymer film is not particularly limited, but polyolefin films (eg, cycloolefin, polyethylene, polypropylene, etc.), polyester A film (eg, polyethylene terephthalate, polyethylene naphthalate), polyvinyl chloride, or a cellulose-based film (eg, triacetyl cellulose) may be used.

Specifically, the polymer film may include a polymer having a glass transition temperature of 70 °C or higher, 80 °C or higher, 90 °C or higher, 100 °C or higher, 110 °C or higher, or 120 or higher. As long as the glass transition temperature satisfies the above range, the type thereof is not particularly limited, and may be appropriately selected in consideration of desired physical properties implementation. For example, when the polymer film is a polyethylene naphthalate film, excellent heat resistance may be realized.

In addition, the polymer film may be, for example, stretched uniaxially or more, and a shrinkage rate of less than 3% when exposed at 120° C. for 1 hour may be used. When the stretched polymer film is used, it can have excellent mechanical strength and can prevent shrinkage at high temperatures. A polymer film satisfying these conditions can be arbitrarily selected from known materials.

Hereinafter, the present invention will be described in detail through embodiments, but the configurations shown in the embodiments and drawings described in the specification are only the most preferred embodiment of the present invention and do not represent all of the technical spirit of the present invention. It should be understood that various equivalents and modifications may be substituted for them at the time of filing.

[Preparation of coating solution]

production example

A first solution was prepared by mixing PVP (weight molecular weight: 40,000) in 15 ml of water so as to be 5% by weight based on the total amount of the ink solution. A second solution was prepared by mixing cellulose in 19.1 ml of ethanol to 1 wt % based on the total amount of the ink solution. Ultrasound was applied to each of the prepared solutions for 1 hour. In a nitrogen atmosphere, the VO ₂ particles were prepared to be 5% by weight based on the total amount of the ink solution, and the first solution and the second solution were mixed and then sonicated for 1 hour to prepare an ink solution for coating.

[Production of optical laminate]

Example 1

0.2 ml of the coating solution prepared in Preparation Example was applied on a polyethylene naphthalate (PEN, glass transition temperature of 120° C.) substrate through a spin coating device (ACE-200). Before application, the surface of the PEN was surface-treated under an oxygen atmosphere through an atmospheric pressure plasma equipment (IDP-1000). Spin coating was spun at 5000 rpm for 30 seconds. The solvent was photo-evaporated from the coating layer by using a light irradiation device for the coating layer. In this case, white light applied from a xenon lamp was used for photoevaporation, the applied voltage was 1210V, the number of pulses was 300, the pulse width was 3ms, the pulse interval was 1.0Hz, and the sintering atmosphere was atmospheric. Then, by changing the light irradiation condition to the light sintering condition, the photo-sintered vanadium dioxide of the photo-evaporated coating layer was manufactured an optical laminate having a thermochromic layer. The applied voltage for optical sintering was 1740V, the number of pulses was 200 times, the pulse width was 3ms, the pulse interval was 1.0Hz, and the sintering atmosphere was atmospheric.

Example 2

An optical laminate was manufactured in the same manner as in Example 1, except that an applied voltage of 1100 V for photoevaporation and a pulse width of 4 ms were used.

Example 3

An optical laminate was manufactured in the same manner as in Example 1, except that the number of pulses of optical sintering was used 50 times.

Example 4

An optical laminate was manufactured in the same manner as in Example 1, except that the number of pulses of optical sintering was used 100 times.

Example 5

An optical laminate was manufactured in the same manner as in Example 1, except that 150 pulses of optical sintering was used.

Example 6

An optical laminate was manufactured in the same manner as in Example 1, except that an applied voltage of 1100 V for photoevaporation, 100 pulses, a pulse width of 4 ms, and a pulse interval of 1.0 Hz were used.

Example 7

An optical laminate was manufactured in the same manner as in Example 1, except that an applied voltage of 1100 V for photoevaporation, 200 pulses, a pulse width of 4 ms, and a pulse interval of 1.0 Hz were used.

Example 8

* An optical laminate was manufactured in the same manner as in Example 1, except that an applied voltage of 1100 V for photoevaporation, 300 pulses, a pulse width of 4 ms, and a pulse interval of 0.9 Hz were used.

Example 9

Spin coating was firstly coated by rotating at 5000 rpm for 30 seconds, then dried at 80 ° C. for 10 minutes, and secondly coated by rotating at 5000 rpm for 30 seconds, and then dried at 80 ° C. Except for drying for 10 minutes Example 1 An optical laminate was manufactured in the same manner as described above.

Comparative Example 1

An optical laminate was manufactured in the same manner as in Example 1, except that an applied voltage of 1740 V and a pulse width of 1 ms for photoevaporation were used.

Comparative Example 2

An optical laminate was manufactured in the same manner as in Example 1 except that an applied voltage of 1390 V and a pulse width of 2 ms for photoevaporation was used.

Comparative Example 3

An optical laminate was manufactured in the same manner as in Example 1, except that 250 pulses of optical sintering were used.

Comparative Example 4

An optical laminate was manufactured in the same manner as in Example 1, except that an applied voltage of 1100 V for photoevaporation, 400 pulses, a pulse width of 4 ms, and a pulse interval of 1.0 Hz were used.

Comparative Example 5

An optical laminate was manufactured in the same manner as in Example 1, except that an applied voltage of 1100 V for photoevaporation, 400 pulses, a pulse width of 4 ms, and a pulse interval of 1.1 Hz were used.

Comparative Example 6

An optical laminate was manufactured in the same manner as in Example 1 except that an applied voltage of 1100 V for photoevaporation, 400 pulses, a pulse width of 4 ms, and a pulse interval of 1.2 Hz were used.

For the optical laminates prepared in Examples and Comparative Examples, the presence or absence of cluster formation was observed using an electron microscope (SEM), and the appearance was visually observed, and the results are shown in the drawings.

1 is a view showing electron microscope images and appearances of optical laminates prepared in Examples 1, 2, Comparative Examples 1 and 2; Specifically, the Examples and Comparative Examples were classified as applying different voltages and pulse widths in the photoevaporation step, and as a result, evaporation occurs more easily as the voltage increases, but when a voltage of 1390V or more is applied (Comparative Example 1 and 2) It was confirmed that the PEN substrate was deformed.

2 is a view showing electron microscope images and appearances of optical laminates prepared in Examples 1, 3, 4, 5, and Comparative Example 3; Specifically, the Examples and Comparative Examples were classified as applying a different number of pulses in the light sintering step, and as a result, the size of the cluster increased as the number of pulses increased. It was confirmed that some of the deformations occurred.

3 is a view showing electron microscope images and appearances of optical laminates prepared in Examples 6, 7, 2, and Comparative Example 4; Specifically, the Examples and Comparative Examples were classified as applying different number of pulses in the photoevaporation step, and as a result, evaporation occurred more as the number of pulses increased, but when the number of pulses was 400 or more (Comparative Example 4), PEN It was confirmed that the substrate was deformed.

4 is a view showing electron microscope images and appearances of optical laminates prepared in Example 8, Example 2, Comparative Example 5, and Comparative Example 6; Specifically, the Examples and Comparative Examples were classified as having different pulse intervals in the photoevaporation step, and as a result, as the pulse interval increased, the photosintering process time was reduced, evaporation started from 1.0Hz or higher, 1.1 Above Hz, it was confirmed that deformation of the PEN (Comparative Examples 5 and 6) substrate occurred. In particular, removal of organic matter did not occur at 1.2 Hz (Comparative Example 6).

The above results suggest that it is important to establish specific conditions for the photoevaporation step and the photosintering step so that deformation of the substrate does not occur.

[Transmittance of optical laminate]

Experimental Example 1

The transmittance of the optical laminate prepared in Example according to the number of light sintering pulses was measured with a UV-VIS photometric system (scan rate 1 nm/sec), and the results are shown in Table 1.

optical sintering
number of pulses P _max BP _min OP _min △IR Example 1 200 67.4% 56% 30.5% 25.5% Example 3 50 69.7% 72.0% 60.6% 11.4% Example 4 100 68.4% 56.0% 36.5% 19.5% Example 5 150 68.8% 56.2% 31.5% 24.7% Comparative Example 3 250 49.2% 53.6% 47.9% 5.7% note P _max : The maximum value of transmittance in the region of 200 to 800 nm
BP _min : Minimum value of transmittance in the range of 2000 to 3000 nm at 25 °C
OP _min : the minimum value of transmittance in the region of 2000 to 3000 nm at 80°C
ΔIR = (BPmin - OPmin)

From this, it was confirmed that, if photoevaporation and photosintering conditions were specifically established for the PEN substrate, excellent visible light transmittance and infrared transmittance were realized by sintering without physical deformation of the substrate. On the other hand, for the optical laminate of Example 9 The transmittance was measured and the results are shown in Table 2.

spin coating P _max BP _min OP _min △IR Example 1 1 time 67.4% 56% 30.5% 25.5% Example 9 Episode 2 60.4% 51.8% 19.7% 32.1%

From Table 2, it was confirmed that the visible light transmittance was decreased due to an increase in the thickness of the coating layer during the second coating, but the infrared transmittance was improved due to a change in the microstructure of the coating layer.

[Measurement of pore area ratio and cluster size]

Experimental Example 2

For the optical laminates prepared in Examples and Comparative Examples, the area ratio of voids and the size of the clusters of the thermochromic layer were measured, and specifically, the image obtained from FE-SEM was calculated using the Image J program, and the results were It is shown in Table 3 below.

Example comparative example One 2 3 4 6 7 3 6 Cluster size (nm) 31.15 26.87 22.23 112.89 29.43 31.27 429.37 measurement
impossible Area ratio of voids (%) 3.10 9.85 5.35 7.02 4.39 9.35 15.78 measurement
impossible

In the case of Comparative Example 6, the organic matter was not removed, so it was impossible to measure the size of the cluster and the area ratio of the pores.

Claims (12)

a substrate that is a polymer film containing a polymer having a glass transition temperature of 70° C. or higher; and a thermochromic layer formed on the substrate, which is the polymer film, and comprising vanadium oxide clusters, wherein the maximum transmittance in the 400 to 800 nm region is 50% or more. In the method of manufacturing an optical laminate,
A forming step of forming an application layer by applying a solution containing vanadium oxide particles, a solvent, a polymer dispersing agent, and a binder on a substrate which is a polymer film;
A photo-evaporation step of irradiating light to remove organic matter from the coating layer; and
A photo-sintering step of photo-sintering the vanadium oxide particles included in the coating layer by irradiating light to prepare a thermochromic layer including vanadium oxide clusters,
The photo-evaporation step and the photos-sintering step repeatedly irradiate light with a constant pulse width, but the number of repeated irradiation of light in the photos-sintering step is less than or equal to the number of repeated irradiation of light in the photo-evaporation step,
The light sintering step repeatedly irradiates light with a constant pulse width, the number of repeated irradiation of the light is 150 to 200 times,
The adhesive strength of the thermochromic layer and the substrate, which is a polymer film, is 50 N/m or more,
The size of the vanadium oxide clusters is 20 to 250 nm,
The optical laminate satisfies the conditions of the following general formula 2,
The output voltage of light in the photosintering step is higher than the output voltage of light in the photoevaporation step,
The pulse width of light in the photosintering step is smaller than the pulse width of light in the photoevaporation step,
The thermochromic layer satisfies the following general formula 1,
A method of manufacturing an optical laminate having a thickness of 0.1 to 5 μm of the thermochromic layer:
[General formula 1]
1≤S(%)≤20
[General formula 2]
BPmin - Opmin ≥ 10%
In the general formula 1, S represents the area ratio of the pores measured by analyzing the image taken of the upper surface of the sample by the image analysis device,
In Formula 2, BPmin represents the minimum value of transmittance at 2000 to 3000 nm at any temperature below the critical temperature, and OPmin represents the minimum transmittance at 2000 to 3000 nm at any temperature above the critical temperature. delete delete The method of claim 1 , wherein the forming step comprises: a first application step of applying a solution on a substrate; and
A method of manufacturing an optical laminate comprising a second coating step of applying a solution on the coating layer applied in the first coating step. The method of claim 1, wherein the forming step is performed by spin coating or spray coating. The method of claim 1 , wherein the photoevaporation step and the photosintering step are performed under an atmospheric atmosphere. delete delete The method of claim 1,
A method for producing an optical laminate, wherein the laminate has a minimum transmittance of 70% or less in the region of 2000 to 3000 nm at any temperature above the critical temperature. delete delete The method of claim 1 , wherein the polymer film is stretched uniaxially or more, and the shrinkage rate is less than 3% when exposed at 120° C. for 1 hour.

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