JP2020067498A - Dimming film, dimmer using the same, and laminated glass - Google Patents

Abstract

To provide a dimming film that does not cause a liquid crystal to deteriorate for a long period and can maintain designability by switching haze at least for two stages even if the dimming film is applied to laminated glass or the like having an interlayer, and to provide a dimmer using the dimming film, and laminated glass.SOLUTION: A dimming film has a liquid crystal layer, and a transparent conductive layer and a transparent film base material on surfaces in both sides of the liquid crystal layer in this order, and can switch haze (white turbidity) according to voltage applied to the liquid crystal layer through the transparent conductive layer at least by two stages. In the dimming film, a side face of the liquid crystal layer is sealed by a sealing material that is resistant to concentrated sulfuric acid, and a voltage retention rate of a mixture of a liquid crystal for forming the liquid crystal layer and the sealing material is equal to or more than 80%. A dimmer and laminated glass use the dimming film.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a light control film having a light control layer using liquid crystal, a light control device using the light control film, and a laminated glass used for a window glass of a building or a transportation facility.

  A liquid crystal light control film (hereinafter referred to as a light control film) is a film that uses liquid crystal and instantaneously switches between “transparent” and “white turbid (opaque)” by turning on or off a power source to control light passing therethrough. The white turbidity (cloudiness) of the light control film is usually called haze.

  There are two types of light control film: normal mode and reverse mode. The normal mode light control film has the function of changing from a cloudy state to a transparent state by applying a voltage, and the reverse mode light control film changes from a transparent state to a cloudy state by applying a voltage. Have the function to

  In the normal mode light control film 80 (see FIG. 7), a polymer liquid crystal composition in which liquid crystal molecules are wrapped with a polymer is used as a liquid crystal layer (light control layer), and the liquid crystal layer is transparent from both sides via transparent conductive layers. It has a structure of being sandwiched between film base materials (hereinafter referred to as PET base materials in the present application). The reverse mode light control film (not shown) further includes an alignment film between the liquid crystal layer and the transparent conductive layer on both sides of the liquid crystal layer.

  The light control film, the light control device using the same, and the laminated glass of the present disclosure can be applied not only to the normal mode method but also to the reverse mode method. Hereinafter, the normal mode method will be described as an example.

  A laminated glass (light control glass) in which a light control film is interposed between a pair of glass plates and bonded and integrated (light control glass) is used for a window glass of a building or a transportation facility (for example, Patent Documents 1 and 2). FIG. 8 is a schematic cross-sectional view showing the basic structure of the laminated glass 90. The laminated glass 90 includes a light control film 80, which is slightly smaller than the soda-lime glass, between a pair of opposing glass plates (hereinafter, exemplified by soda-lime glass in the present application). In FIG. 8, the mechanism for supplying a voltage to the pair of transparent conductive layers is not shown.

  When the laminated glass is used as a window glass of a building, for example, by changing the transparent state and the opaque state of the light control film, from the transparent state where the scenery and decorations inside and outside can be seen to the opaque state, By adjusting the haze, the intensity of light from inside and outside can be adjusted, and the design can be improved.

  The interlayer film shown in FIG. 8 has an adhesive function for sandwiching blue plate glass by sandwiching the light control film between the blue plate glasses and bonding them together. The intermediate film may include an ultraviolet absorber, an antioxidant, a light stabilizer, a dye, a pigment or the like depending on the additional function. A light control film and a pair of soda lime glass are laminated via an intermediate film, defoamed under reduced pressure, and then heated and pressurized to be integrated.

  Considering the load on the light control film, the material of the interlayer film is preferably a thermoplastic resin that melts at 140 ° C. or lower, and more preferably a resin that melts at 100 ° C. or lower. Examples of the candidate resin include polyvinyl butyral (PVB), ethylene-vinyl acetate copolymer (EVA), polyurethane, polyvinyl chloride, ionomer resin, cellulose diacetate, cellulose triacetate, etc., and PVB and EVA are usually used. Has been done.

JP-A-2-24630 JP, 2007-4085, A

  However, in the conventional laminated glass, PVB, EVA, etc., which are the components of the intermediate film, leaches into the liquid crystal layer and reacts with the liquid crystal layer in the light control film, so that the liquid crystal at the edge of the light control film becomes transparent. However, there is a problem that the normal dimming function is lost due to deterioration such as.

  The present disclosure has been made in order to solve the above problems, and an object thereof is to apply a haze of two or more stages without deterioration of liquid crystal for a long time even when applied to a laminated glass or the like having an intermediate film. It is intended to provide a light control film capable of maintaining a design property by switching between, and a light control device and a laminated glass using the light control film.

In order to solve the above problems, the light control film according to the present invention has a liquid crystal layer, and on both sides of the liquid crystal layer, a transparent conductive layer and a transparent film substrate are provided in this order, and the transparent conductive layer. A light control film for changing haze (white turbidity) according to a voltage applied to the liquid crystal layer through
The side surface of the liquid crystal layer is sealed with a sealing material resistant to concentrated sulfuric acid,
The voltage holding ratio of the mixture of the liquid crystal forming the liquid crystal layer and the sealing material is 80% or more,
The light control film is characterized by that.
Here, “tolerant to concentrated sulfuric acid” means that the mass change rate before and after the test of immersing in a concentrated sulfuric acid aqueous solution (pH 3.0) for 24 hours is 3% or less based on JIS K 7114. .
The voltage holding ratio is measured under the condition that the mixture sample of the liquid crystal and the encapsulant is placed in a constant temperature bath at 25 ° C., and after about 10 minutes have passed, the applied voltage is 5 V and the holding time is 16.61 ms.
The mass change rate is
(Mass of sealing material before immersion-mass of sealing material after immersion) / mass of sealing material before immersion × 100 (%).

  Further, in the light control film according to the present invention, the sealing material has a thickness of 30 μm or more in a direction perpendicular to the side surface of the liquid crystal layer, and a length in a direction parallel to the side surface of 100 μm or more and 1500 μm or less. It is preferable.

  Further, in the light control film according to the present invention, it is preferable that the center line of the film thickness of the light control film and the center line of the length in the direction parallel to the side surface of the sealing material match.

  Further, in the light control film according to the present invention, the entire side surface of the light control film may be sealed with the sealing material.

A light control device according to the present invention, the light control film according to any one of claims 1 to 4,
An AC power supply for supplying a voltage to the transparent conductive layer in the light control film,
A switching device for switching the presence / absence of voltage supply from the AC power supply to the transparent conductive layer, and a light control device.

The laminated glass according to the present invention is a laminated glass characterized in that an intermediate film and the light control device according to claim 5 are sandwiched and integrated between a pair of glasses.

  According to the present disclosure, even when applied to a laminated glass or the like provided with an intermediate film, a light control film that does not deteriorate the liquid crystal for a long period of time and can maintain design characteristics by switching haze in two or more stages, and a light control film using the light control film. An optical device and a laminated glass are obtained. At the same time, it is stable in various light control devices equipped with an interlayer film, such as windows for buildings and transportation, sunroofs and sun visors for automobiles, partitions that can block the field of view, screens, notice boards, and show windows. It can be used and extended in life.

It is (a) schematic cross section which shows the layer structure of the light control film which concerns on 1st Embodiment of this indication, (b) A schematic bird's-eye view. It is a schematic cross section which shows the layer structure of the light control film which concerns on 2nd Embodiment of this indication. It is a schematic cross section which shows the basic composition of the light control apparatus which concerns on 3rd Embodiment of this indication. It is a schematic cross section which shows the basic composition of the light control apparatus which concerns on 4th Embodiment of this indication. It is a schematic cross section which shows the basic composition of the laminated glass which concerns on 5th Embodiment of this indication. It is a schematic cross section which shows the basic composition of the laminated glass which concerns on 6th Embodiment of this indication. It is a schematic cross section which shows the laminated constitution of the conventional light control film. It is a schematic cross section which shows the basic composition of the conventional laminated glass.

  Hereinafter, a light control film according to an embodiment of the present disclosure, a light control device using the same, and a laminated glass will be described with reference to the drawings. The same reference numerals are given to the same components unless there is a reason for convenience. In each drawing, the thickness and ratio of components may be exaggerated for ease of viewing, and the number of components may be reduced and illustrated. Further, the present disclosure is not limited to the following embodiments as they are, and can be embodied by appropriate combinations and modifications without departing from the spirit of the present invention.

[Light control film]
FIG. 1A is a schematic cross-sectional view showing the layer structure of the light control film according to the first embodiment of the present disclosure. The light control film 10 according to the first embodiment includes a liquid crystal layer and a transparent conductive layer and a PET base material on both surfaces of the liquid crystal layer in this order, and a voltage is applied to the liquid crystal layer through the transparent conductive layer. The haze (white turbidity) can be switched in two or more steps. Further, at least side surfaces including both sides of the liquid crystal layer are sealed with a sealing material.

  FIG. 1B is a schematic bird's-eye view of the light control film according to the first embodiment of the present disclosure. In this way, the sealing material seals the side surface including at least both sides of the liquid crystal layer of the conventional light control film having no sealing material over the peripheral portions of the four sides. The above-mentioned FIG. 1A corresponds to a sectional view taken along the line A-A ′ in FIG.

  The encapsulant is resistant to concentrated sulfuric acid. Here, “having resistance to concentrated sulfuric acid” means that the mass change rate before and after the test of immersing in a concentrated sulfuric acid aqueous solution (pH 3.0) for 24 hours is 3% or less based on JIS K 7114. Means

  Further, the sealing material is characterized in that the voltage holding ratio of the mixture of the liquid crystal forming the liquid crystal layer and the sealing material is 80% or more. The encapsulant having a voltage holding ratio of less than 80% is not preferable because it may generate an acid that affects the liquid crystal.

  The thickness of the sealing material in the direction perpendicular to the side surface of the liquid crystal layer (Dx in FIGS. 1A and 1B) in order to suppress the reaction between the intermediate film and the liquid crystal layer and exert sufficient sealing performance. Is 30 μm or more, and the length in the direction parallel to the side surface (Dz in FIGS. 1A and 1B) is preferably 100 μm or more and 1500 μm or less.

  In FIG. 1A, the center line (f1 = f2) Cf of the entire thickness of the light control film 10 and the center line (s1 = s2) of the length Dx in the direction parallel to the side surface of the sealing material. It is desirable that the line Cs) be the same because the sealing material has a uniform barrier property in the Z direction. Incidentally, since the upper and lower transparent conductive layers and the PET base material which sandwich the liquid crystal layer usually have the same film thickness, the center line Cf coincides with the center line of the film thickness of the liquid crystal layer only.

  FIG. 2 is a schematic cross-sectional view showing the layer structure of the light control film according to the second embodiment of the present disclosure. The encapsulant may thus be provided on the entire side surface (Dz 'in FIG. 2) of the light control film 20. Depending on the manufacturing process, it may be easier to provide the sealing material on the entire side surface rather than partially providing the sealing material on the side surface including the liquid crystal layer. However, it may be disadvantageous in terms of material cost, and therefore either of FIG. 1 and FIG. 2 may be appropriately compared and selected.

[Dimmer]
FIG. 3 is a schematic cross-sectional view showing the basic configuration of the light control device 30 according to the third embodiment of the present disclosure. Further, FIG. 4 is a schematic cross-sectional view showing the basic configuration of the light control device 40 according to the fourth embodiment of the present disclosure. The light control devices 30 and 40 respectively include the light control films 10 and 20 of the present disclosure, and an AC power supply capable of applying a voltage to the transparent conductive layer and whether or not a voltage from the AC power supply is applied to the transparent conductive layer. Equipped with a switch to switch between. In addition, in the light control device 40 according to the fourth embodiment of FIG. 4, a part (preferably a part of four corners in plan view) of the region of the sealing material that covers the upper and lower transparent conductive layers is removed. It has a through hole and is connected to an AC power supply.

  Therefore, the basic form is the form shown in FIGS. 1 and 2 in which the light control films 10 and 20 and the AC power supply are connected via a switch. The AC power supply is preferably a variable power supply whose effective voltage can be changed. Thereby, the degree of light transmission or scattering is controlled, the haze is variously changed to improve the design, and the light control film of the present disclosure can be used stably for a long period of time.

[Laminated glass]
FIG. 5 is a schematic cross-sectional view showing the basic configuration of the laminated glass 50 according to the fifth embodiment of the present disclosure. Further, FIG. 6 is a schematic cross-sectional view showing the basic configuration of the laminated glass 60 according to the sixth embodiment of the present disclosure. The laminated glasses 50 and 60 are laminated glasses in which an intermediate film and the light control devices 30 and 40 of the present disclosure are sandwiched between a pair of glasses to be integrated. The intermediate film has a function of adhering the light control film to the soda lime glass, and may contain an ultraviolet absorber, an antioxidant, a light stabilizer, a dye, a pigment or the like depending on the application. In the laminated glass 60 according to the sixth embodiment of FIG. 6, a part (preferably a part of the four corners in plan view) of the region of the sealing material and the intermediate film covering the upper and lower transparent conductive layers is removed. Then, a through hole is opened to connect to the AC power supply.

  In the laminated glass of the present disclosure, when the light control film becomes transparent by switching the power source, it becomes transparent glass and the other side of the glass can be visually recognized. Further, when it becomes cloudy and opaque, it can also function as a screen for visually recognizing an image projected on glass. Further, as described above, the effective voltage of the AC power source is changed, the haze is changed variously, the designability is improved, and the light control film of the present disclosure can be used stably for a long period of time.

  Hereinafter, as examples and comparative examples, methods and results for evaluating the acid resistance test of the sealing material, the voltage holding ratio measurement, the barrier property of the laminated glass, and the design property will be described. As the encapsulating material, seven kinds of acryl + epoxy resin (the same in Examples 1 and 4 to 10, the same in Examples 2 and 3 and Comparative Examples 1 to 4) were used.

[Acid resistance test of encapsulant]
Based on JIS K 7114, the mass change rate (%) before and after the test of immersing the sealing material alone in a concentrated sulfuric acid aqueous solution (pH 3.0) for 24 hours was measured. Concentrated sulfuric acid was used because it has higher acidity than other acids.

[Measurement of voltage holding ratio]
A mixture of liquid crystal and a sealing material was prepared and the voltage holding ratio (%) was measured. If a material (acid or the like) that deteriorates the liquid crystal is generated by mixing, the voltage holding ratio is lowered.

[Barrier properties and design of laminated glass]
(Production of laminated glass for evaluation)
Two substrates with ITO (Indium Tin Oxide) as a transparent conductive layer were prepared, and a spacer having a height of 25 μm was applied to one of the substrates. Next, after the liquid crystal composition is dropped onto the substrate surface by a general ODF method (One-Drop-Fill method, which is also called a liquid crystal dropping method, a vacuum dropping method, etc.), the ITO surfaces of the other substrate face each other. Facing each other, and using a metal halide lamp with an illuminance of 60 mW that cuts wavelengths of 350 nm or less, irradiate 7 J / cm ² of ultraviolet rays in terms of 365 nm (temperature in the irradiation device is controlled at 25 ° C.) to perform bonding, A prototype of the light control film was obtained.

  Next, a substrate with an adhesive material was laminated on the prototype of the above-mentioned light control film, and a light control film was obtained by half-cutting the ends of the above-mentioned master for electrical conduction with ITO on both sides. The light control film is cut into a size of 6 cm × 6 cm and has a width Dz (μm) and a film thickness Dx (μm) (see FIG. 1B) on the side surface including at least the liquid crystal layer over the peripheral portions of the four sides in a plan view. After applying the sealing material as described above and irradiating it with black light until tackiness disappears, sandwich the light control film having the interlayer film (PVB) and the sealing material with two pieces of glass, heat compress and evaluate. A laminated glass was prepared. The values of Dz and Dx were appropriately changed for the laminated glass of Examples 1 to 10 and Comparative Examples 1 to 4.

(Evaluation methods)
The laminated glass produced from a position 1 m away was visually observed, and the one in which the sealing material was not conspicuous was regarded as having a good design (◯), and the liquid crystal at the end portion was not deteriorated immediately after the production and 24 hours later. It was judged that the liquid crystal barrier property of the sealing material was good (◯).

[Evaluation results]
Table 1 collectively shows the conditions and the evaluation results for the evaluation of the sealing materials and laminated glass of Examples 1 to 10 and Comparative Examples 1 to 4 described above.

  From Table 1, as shown in the present disclosure, the side surfaces of the liquid crystal layer are sealed with a sealing material, and the combinations prepared in Examples 1 to 10 satisfying the conditions of the concentrated sulfuric acid resistance and the voltage holding ratio defined in the claims. As for the glass, the design property was good, and the liquid crystal was not deteriorated, and the barrier property was also good. On the other hand, in Comparative Examples 1 and 2 having a voltage holding ratio of less than 80% and Comparative Examples 3 and 4 having a low resistance to concentrated sulfuric acid, deterioration of the liquid crystal occurred after 24 hours. In Comparative Example 1 having a particularly low voltage holding ratio and Comparative Example 4 having a particularly low resistance to concentrated sulfuric acid, deterioration of the liquid crystal occurred immediately after the production of the laminated glass.

10, 20 ... Light control film 30, 40 ... Light control device 50, 60 ... Laminated glass 80 ... Conventional light control film 90 ... Conventional laminated glass

Claims (6)

A liquid crystal layer, and on both sides of the liquid crystal layer, a transparent conductive layer and a transparent film substrate are provided in this order, and a light control film that changes the haze according to the voltage applied to the liquid crystal layer through the transparent conductive layer. And
The side surface of the liquid crystal layer is sealed with a sealing material resistant to concentrated sulfuric acid,
The voltage holding ratio of the mixture of the liquid crystal forming the liquid crystal layer and the sealing material is 80% or more,
A light control film characterized in that The thickness of the sealing material in the direction perpendicular to the side surface of the liquid crystal layer is 30 μm or more, and the length in the direction parallel to the side surface is 100 μm or more and 1500 μm or less.
The light control film according to claim 1, wherein the light control film is a light control film. The center line of the thickness of the light control film and the center line of the length in the direction parallel to the side surface of the encapsulant are matched,
The light control film according to claim 1 or 2, characterized in that. The entire side surface of the light control film is sealed with the sealing material,
The light control film according to claim 1, wherein the light control film is a light control film. The light control film according to claim 1,
An AC power supply for supplying a voltage to the transparent conductive layer in the light control film,
A switcher for switching the presence / absence of voltage supply from the AC power supply to the transparent conductive layer, a light control device. An intermediate film and the light control device according to claim 5 are sandwiched between a pair of glasses and integrated.
Laminated glass characterized by that.