KR102539689B1 - Photochromic sheet with excellent discoloring performance and manufacturing method thereof - Google Patents

Abstract

The present invention relates to a photochromic sheet capable of discoloration by irradiated light and a method for manufacturing the same, wherein electrons move between the interface of an electrolyte layer and an adjacently stacked discoloration layer by the change of irradiated light by forming a plurality of pores in a photosensitive layer. The present invention relates to a photochromic sheet having excellent color change efficiency and color change rate by improving the amount and speed of the color change and a method for manufacturing the same.
For this purpose, the photochromic sheet of the present invention includes a color changing layer, a photosensitive layer, and an electrolyte layer between transparent substrates. The photosensitive layer includes photosensitive particles, a binder, and a first solvent and a second solvent having different boiling points. formed by mixing

Description

Photochromic sheet with excellent discoloring performance and manufacturing method thereof {Photochromic sheet with excellent discoloring performance and manufacturing method thereof}

The present invention relates to a photochromic sheet capable of discoloration by irradiated light and a method for manufacturing the same, and more particularly, by forming a plurality of pores in a photosensitive layer, an interface between a discolored layer and an electrolyte layer stacked adjacent to each other by a change in irradiated light. The present invention relates to a photochromic sheet having excellent discoloration efficiency and discoloration rate by improving the amount and speed of electrons moving between cells and a method for manufacturing the same.

Photochromism is a phenomenon that is not colored when sunlight is not irradiated, but is discolored by photoexcited electrons when sunlight is irradiated. It is being studied for the purpose of adjusting the light transmittance or reflectance of automobile mirrors, and recently, the possibility of application as an energy-saving product is receiving great attention.

The structure of such a photochromic sheet is shown in FIG. 7, and a discoloration layer 120, a photosensitive layer 130, and an electrolyte layer 140 are interposed between a pair of transparent sheets 110 and 150 facing each other at a predetermined interval. ) are stacked, and when irradiated with sunlight, electrons excited in the photosensitive layer 130 move to the color-changing layer 120 and are colored by electrochemical bonding, and when sunlight is not irradiated, electrons bound in the color-changing layer are desorbed and discoloration takes place.

In order for such a photochromic sheet to be used effectively in the application field, color change efficiency and color change rate are important so that it can be colored or discolored by rapidly reacting to changes in irradiated light.

Republic of Korea Patent Publication No. 10-2013-0013225 (Title of invention: Automotive glass using photochromic film) Republic of Korea Patent Registration No. 10-0802891 (Title of Invention: Photochromic Film or Plate Manufacturing Method)

Accordingly, an object of the present invention is to provide a photochromic sheet and a method for manufacturing the same, which are quickly colored and decolored according to changes in irradiated light, thereby improving color changing efficiency and speed.

In order to achieve the above object, the present invention is a photochromic sheet including a color changing layer, a photosensitive layer, and an electrolyte layer between transparent substrates, wherein the photosensitive layer includes photosensitive particles, a binder, and a first solvent having different boiling points. and the second solvent are mixed to form.

At this time, the photosensitive layer of the present invention is formed by mixing a first mixed solvent in which photosensitive particles and a first solvent are mixed and a second mixed solvent in which a binder and a second solvent are mixed, and the photosensitive particles are titanium dioxide ( TiO ₂ ), zinc oxide (ZnO), niobium oxide (Nb ₂ O ₅ ), tin oxide (SnO ₂ ), zinc tin oxide (Zn ₂ SnO ₄ ), or strontium titanium oxide (SrTiO ₃ ). do.

Here, the first solvent of the present invention is methanol, ethanol, isopropyl alcohol, benzene, methyl ethyl ketone, diethyl ether, methyl It is formed of at least one selected from methyl acetate and ethyl acetate, and has a boiling point of less than 100°C.

In addition, the second solvent of the present invention is Butyl Cellosolve, Ethyl Carbitol, Cellosolve Acetate, Methyl Diacetone Ether, Cyclohexanone, It is formed of at least one selected from butyl carbitol and methyl carbitol, and has a boiling point of 150 to 200 ° C.

At this time, the first mixed medium and the second mixed medium of the present invention are mixed in a ratio.

In addition, the binder of the present invention is formed of at least one selected from cellulose, styrene butadiene rubber, polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE).

In addition, the present invention is a method of manufacturing a photochromic sheet by laminating a color-changing layer, a photosensitive layer, and an electrolyte layer between transparent substrates, wherein the color-changing layer contains photosensitive particles, a binder, and a first solvent having a different boiling point and a second agent. 2 Solvents are mixed to form a photosensitive layer.

Here, the light-sensitive layer of the present invention is wet-coated on the color-changing layer in a sol state, and is formed by mixing a first mixed solvent composed of a mixture of photosensitive particles and a first solvent, a binder and a second solvent. The second mixed solvent is mixed and wet-coated on the discoloration layer.

At this time, in the present invention, based on the total weight of the first mixed medium, 15 to 30% by weight of the light sensitive particles and 70 to 85% by weight of the first solvent are mixed to form the first mixed medium, and the total weight of the second mixed medium is mixed. 1 to 10% by weight of the binder and 90 to 99% by weight of the second solvent are mixed to form the second mixed medium, and the first mixed medium and the second mixed medium are mixed in a ratio.

In addition, in the present invention, the coated light-sensitive layer is sequentially heated to different temperatures to dry the light-sensitive layer. After the primary drying of evaporating the first solvent by heating the light-sensitive layer, the light-sensitive layer is heated again The remaining second solvent is evaporated and dried secondarily to dry the photosensitive layer.

At this time, the difference between the primary drying and secondary drying heating temperatures of the present invention is 50 ° C or more.

In the photochromic device according to the present invention, as the photosensitive layer in which solvents having different boiling points are mixed with photosensitive particles and a binder is sequentially heated and dried to form a plurality of pores therein due to the evaporated solvent, the irradiated light As a result of the change, the amount and speed of electrons moving between the discoloration layer and the electrolyte layer interface that are adjacently stacked along the plurality of pores are improved, resulting in discoloration even with a small light change. As a result, not only the color change efficiency is improved, but also rapid discoloration with a fast response speed is possible. Thus, it can be usefully applied to a large area such as a building field as well as a small area such as a car mirror.

1 is a cross-sectional view of a photochromic sheet according to the present invention.
2 is a flow chart of a method of forming a photosensitive layer of the present invention.
3 is a cross-sectional view showing a light-sensitive layer applied in a sol state to a color-changing layer according to the present invention.
FIG. 4 is a cross-sectional view illustrating a state in which the first solvent is evaporated by primarily drying the light-sensitive layer of FIG. 3 .
5 is a cross-sectional view illustrating a state in which the second solvent is evaporated by secondary drying of the photosensitive layer of FIG. 4 .
6 is a cross-sectional view showing a state in which electrons photoexcited in the photochromic sheet of the present invention move to the color-changing layer.
7 is a cross-sectional view showing a state in which photoexcited electrons move to a color-changing layer in a conventional photochromic sheet.

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

This embodiment is provided to more completely explain the present invention to those with average knowledge in the art, and the shape of elements in the drawings, the size of elements, the spacing between elements, etc. are emphasized for clearer explanation. It can be exaggerated or reduced to express.

In addition, in the description of the embodiments, if it is determined that the technical features of the present invention may be unnecessarily obscured as matters already obvious to those skilled in the art, such as known functions or known configurations related in principle, the detailed I will omit the explanation.

Figure 1 is a cross-sectional view of a photochromic sheet 100 according to the present invention. 50), the color changing layer 20, the photosensitive layer 30, and the electrolyte layer 40 are stacked and formed.

The first and second transparent substrate layers 10 and 50 may be formed of transparent plastic films or glass having a light transmittance of 95% or more so that sunlight irradiated from the outside is transmitted to the inside. Examples of transparent plastic films include films such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), polypropylene (PP), polyimide (PI), and triacetyl cellulose (TAC). A film coated with a transparent conductive material such as FTO, ITO, IZO, or AZO may be used. The first and second transparent substrate layers 10 and 50 are formed to a thickness of 1 to 5 mm.

The color-changing layer 20 is formed on the first transparent substrate layer 10 and is colored or discolored by a change in irradiated light, which is generated and moved in the light-sensitive layer 30 and the electrolyte layer 40 according to a change in light. It is a layer that is colored or decolored according to the chemical reaction of one electron. The discoloration layer 20 includes tungsten oxide (WO ₃ ), titanium oxide (TiO ₂ ), molybdenum oxide (MoO ₃ ), vanadium oxide (V ₂ O ₅ ), thallium oxide (Tl ₂ O), and niobium oxide (Nb ₂ O). ₅ ) and copper oxide (CuO).

The electrolyte layer 40 is a layer provided adjacent to the light-sensitive layer 30 to supply electrons that are excited by the light-sensitive layer 30 and supplied to the color-changing layer 20 to be lost. It may be formed by mixing PEGDMe and a photoinitiator, and is formed by mixing an electrolyte salt. As the electrolyte salt, a compound containing H ⁺ , Li ⁺ , Na ⁺ , K ⁺ , Rb ⁺ , Cs ⁺ may be used, and for example, a lithium salt compound such as LiClO ₄ , LiBF ₄ , LiAsF ₆ , or LiPF ₆ may be used. can Such an electrolyte layer 40 is formed between the photosensitive layer 30 and the second transparent substrate 50 by being cured by UV light or heat.

The light-sensitive layer 30 formed adjacent to the electrolyte layer 40 is a layer that supplies electrons excited by irradiated light to the color-changing layer 20, and is formed between the color-changing layer 20 and the electrolyte layer 40. Multiple pores are formed inside to improve the amount and speed of moving electrons.

A method of forming the photosensitive layer 30 for this purpose is shown in FIG. 2 . In the light-sensitive layer 30 of the present invention, a step of mixing light-sensitive particles and a first solvent to form a first mixed medium (S110), and a step of mixing a binder and a second solvent to form a second mixed medium (S120). ), wet-coating the light-sensitive layer in a sol state in which the first mixed solvent and the second mixed solvent are mixed onto the discoloration layer (S130), heating the coated light-sensitive layer 30 to dry it first It is formed through the step of evaporating the first solvent (S140), and the step of evaporating the second solvent by heating the light-sensitive layer 30 and secondarily drying it (S150).

First, the first mixed medium is prepared by dispersing light-sensitive particles in which electrons are excited by irradiated light in the first solvent (S110). The photosensitive particle is an inorganic material having an energy band gap so that electrons can be excited from the ground state to the excited state by irradiated light, such as titanium dioxide (TiO ₂ ) and zinc oxide (ZnO). ), niobium oxide (Nb ₂ O ₅ ), tin oxide (SnO ₂ ), zinc tin oxide (Zn ₂ SnO ₄ ), or strontium titanium oxide (SrTiO ₃ ) may be used. Such light-sensitive particles are formed in a particle size of nanoscale, preferably 1 to 100 nm, in order to increase the specific surface area.

The first solvent in which the photosensitive particles are dispersed is methanol, ethanol, isopropyl alcohol, benzene, methyl ethyl ketone, diethyl ether, It is formed of at least one selected from methyl acetate and ethyl acetate, and is formed to have a boiling point lower than that of the second solvent, preferably 100° C. or less.

At this time, the first mixed medium is formed by mixing 15 to 30% by weight of the light-sensitive particles and 70 to 85% by weight of the first solvent based on the total weight of the first mixed solvent, and the mixing ratio of the light-sensitive particles is 30%. If it exceeds , it is difficult to be coated on the color-changing layer 20 , and if the mixing ratio of the light-sensitive particles is less than 15%, the amount of electrons supplied to the color-changing layer 20 during photo-sensitization is insufficient, and thus the color-changing efficiency and color-change rate decrease.

Next, the second mixed medium is prepared by dispersing a binder binding the light-sensitive particles in the second solvent (S120). As the binder, a polymer binder is used to more firmly bind the photosensitive particles, and any one selected from cellulose, styrene butadiene rubber, polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE) One or more may be used.

The second solvent in which the binder is dispersed is a solvent having a higher boiling point than the first solvent, and includes Butyl Cellosolve, Ethyl Carbitol, Cellosolve Acetate, and Methyl Diacetone Ether. ), cyclohexanone, butyl carbitol, methyl carbitol, or any one or more selected from among may be used. As will be described later, the boiling point of the second solvent is to have a boiling point of at least 50 ° C. or more, preferably 150 to 200 ° C. is formed

Here, the second mixed solvent is formed by mixing 1 to 10% by weight of the binder and 90 to 99% by weight of the second solvent based on the total weight of the second mixed solvent, and discoloration occurs when the mixing ratio of the binder exceeds 10%. It is difficult to coat the layer 20, and if the mixing ratio of the light-sensitive particles is less than 1%, it is difficult to stably bind the light-sensitive particles.

After the first and second mixed solvents are formed, the first mixed solvent and the second mixed solvent are stirred and mixed to wet-coate the light-sensitive layer in a sol state onto the color-changing layer (S130). In this way, as the first mixed medium and the second mixed medium are stirred and mixed, the light-sensitive particles and the binder are uniformly dispersed in the mixed solution. Here, the first mixed solvent and the second mixed solvent are mixed at 40 to 60% by weight and formed in a sol state, so that known methods such as slot die coating, spray coating, spin coating, doctor blade coating, roller coating, etc. wet coating method. FIG. 3 shows a light-sensitive layer 30 applied in a sol state to the color-changing layer 20. The light-sensitive particles 31 and the binder 32 are added to the first and second solvent mixtures 33. are evenly distributed.

As such, when the photosensitive layer 30 is applied to the color changing layer 20 in a sol state, the photosensitive layer 30 is dried by sequentially heating at different temperatures. To this end, the wet-coated light-sensitive layer 30 is heated and primarily dried to evaporate the first solvent (S140). 4 shows the photosensitive layer 30 in which the first solvent is evaporated, the first solvent having a low boiling point evaporates and the remaining second solvent 34 having a high boiling point contains photosensitive particles 31 and a binder ( 32) is dispersed.

Next, the firstly dried light-sensitive layer 30 is heated again and secondarily dried to completely dry the light-sensitive layer 30 by evaporating the second solvent (S150). A light sensitive layer 30 is shown in FIG. 5 . As shown in FIG. 5, the light-sensitive layer 30 is formed by the binder 32 uniformly dispersed while the first and second solvents are evaporated through the first and second drying to form a plurality of pores O therein. The photosensitive particles 31 are stably bonded. When the photosensitive layer 30 is dried in this way, the photochromic sheet 100 is completed by stacking the electrolyte layer 40 and the second transparent substrate 50. .

The operation of the photochromic sheet according to the present invention made as described above is as follows.

When light transmitted through the first transparent substrate layer 10 is incident on the photosensitive particles 31 of the photosensitive layer 30, electrons in the photosensitive particles 31 are excited from the ground state and moved to the color-changing layer 20. At the same time, the photosensitive layer 30 receives electrons from the contacting electrolyte layer 40 and continuously transfers them to the color-changing layer 20, thereby discoloring the color-changing layer 20.

The flow of electrons in the photochromic sheet 100 is shown in FIG. 6, and compared with FIG. As the excited electrons move along the plurality of pores O formed therein, the amount and speed of the electrons transferred to the discoloration layer 20 are increased.

Therefore, the photochromic sheet of the present invention increases the amount and speed of moving electrons even with a small light change, so that the discoloration efficiency is improved, and the response speed is also rapidly discolored. It can also be usefully applied to large areas.

The present invention described above is not limited to the described embodiments, and it is obvious to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. Therefore, such variations or modifications should fall within the scope of the claims of the present invention.

10: first transparent substrate layer 20: discoloration layer
30: light-sensitive layer 31: light-sensitive particles
32: binder 33: first and second solvent mixture
34: second solvent 40: electrolyte layer
50: second transparent substrate layer 100: photochromic sheet

Claims (18)

In the photochromic sheet comprising a discoloration layer, a photosensitive layer and an electrolyte layer between transparent substrates,
The photosensitive layer,
a first mixed solvent in which light sensitive particles and a first solvent are mixed; and,
A second mixed solvent in which a binder and a second solvent are mixed; is formed by mixing,
The first solvent and the second solvent have different boiling points,
The photochromic sheet, characterized in that the first mixed solvent and the second mixed solvent are mixed in 40 to 60% by weight, respectively. delete According to claim 1,
The photosensitive particle may be titanium dioxide (TiO ₂ ), zinc oxide (ZnO), niobium oxide (Nb ₂ O ₅ ), tin oxide (SnO ₂ ), zinc tin oxide (Zn ₂ SnO ₄ ) or strontium titanium oxide (SrTiO ₃ ) Photochromic sheet, characterized in that formed of any one or more selected from. According to claim 1,
The first solvent is methanol, ethanol, isopropyl alcohol, benzene, methyl ethyl ketone, diethyl ether, methyl acetate Acetate), ethyl acetate (Ethyl acetate), characterized in that the photochromic sheet formed of any one or more selected. According to claim 4,
The photochromic sheet, characterized in that the boiling point of the first solvent is 100 ℃ or less. According to claim 1,
The second solvent is butyl cellosolve, ethyl carbitol, cellosolve acetate, methyl diacetone ether, cyclohexanone, butyl carbitol (Butyl Carbitol), methyl carbitol (Methyl Carbitol), a photochromic sheet, characterized in that formed of any one or more selected. According to claim 6,
The photochromic sheet, characterized in that the boiling point of the second solvent is 150 ~ 200 ℃. According to claim 1,
The photochromic sheet, characterized in that the binder is formed of at least one selected from cellulose, styrene butadiene rubber, polyvinylidene fluoride (PVDF), and polytetrafluoroethylene (PTFE). delete In the method for manufacturing a photochromic sheet by laminating a color changing layer, a photosensitive layer and an electrolyte layer between transparent substrates,
The photosensitive layer,
It is formed by mixing a first mixed solvent composed of a mixture of light sensitive particles and a first solvent and a second mixed solvent composed of a mixture of a binder and a second solvent and wet-coating the discoloration layer,
The first solvent and the second solvent have different boiling points,
The method for producing a photochromic sheet, characterized in that the first mixed solvent and the second mixed solvent are mixed in 40 to 60% by weight, respectively. According to claim 10,
The photosensitive layer is a method for producing a photochromic sheet, characterized in that the wet coating on the color changing layer in a sol (sol) state. delete According to claim 10,
A method for producing a photochromic sheet, characterized in that the first mixed solvent is formed by mixing 15 to 30% by weight of the photosensitive particles and 70 to 85% by weight of the first solvent based on the total weight of the first mixed solvent. According to claim 10,
A method for producing a photochromic sheet, characterized in that a second mixed solvent is formed by mixing 1 to 10% by weight of a binder and 90 to 99% by weight of a second solvent based on the total weight of the second mixed solvent. delete According to claim 10,
Method for producing a photochromic sheet, characterized in that by heating the coated photosensitive layer sequentially at different temperatures to dry the photosensitive layer. According to claim 16,
After primary drying in which the first solvent is evaporated by heating the light-sensitive layer, the light-sensitive layer is heated again to evaporate the remaining second solvent and secondarily dried to dry the light-sensitive layer. A method for producing a discoloration sheet. According to claim 17,
The method of manufacturing a photochromic sheet, characterized in that the difference between the primary drying and secondary drying heating temperature is 50 ℃ or more.

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