Intermediate film structure for sandwich panel, and sandwich panel structure

Abstract

Provided are: an intermediate film structure for a sandwich panel, said intermediate film structure having a heat-insulating effect and being capable of obtaining a sufficient contrast difference between the maximum visible light transmittance and the minimum visible light transmittance when the light transmittance is controlled; and a sandwich panel structure. An intermediate film structure (1) for a sandwich panel, which is used by being disposed between two transparent panels (30, 31), is provided with thermoplastic resin sheets (20, 21), and a dimming member (10) disposed so as to be sandwiched between the thermoplastic resin sheets (20, 21). In laminated glass obtained by bonding two transparent glass plates (30, 31) via the interlayer structure (1) for laminated glass, the difference in visible light transmittance during driving and during non-driving of the dimming member (10) is 20% or more, and the total sunlight transmittance (Tts) of the dimming member (10) during driving and during non-driving is 70% or less.

Description

Technical Field

[0001] The present invention relates to an interlayer film structure for a sandwich panel to be sandwiched between two transparent panels, and the sandwich panel structure. Background Art

[0002] In recent years, with the development of smart technologies such as smart homes and smart mobility, panels, which are components of devices, are expected to adapt to smart functions that are realized through electrical control.

[0003] To make sandwich panels, a type of panel, more intelligent, it is necessary to incorporate intelligent components (dimming components) that function through electrical control into the sandwich panel. To embed dimming components of varying shapes and thicknesses within the sandwich panel structure, at least two interlayer films are required.

[0004] In sandwich panel structures, a representative example of an intelligent component (dimming component) that exhibits functionality through electrical control is a film that reversibly controls light transmittance, known as a dimming film. Sandwich panel structures incorporating dimming films using various dimming methods (PDLC, SPD, EC) have been studied (for example, see Patent Document 1).

[0005] In sandwich panel structures incorporating a dimming film, special glass, such as infrared-reflective flat glass, is sometimes used to improve thermal insulation and suppress thermal degradation of the dimming film. While the use of special glass improves thermal insulation and suppresses thermal degradation, it also presents a problem: the transmittance is reduced due to the influence of the special glass. As a result, the difference between the maximum and minimum visible light transmittance when controlling light transmittance decreases, making it difficult to achieve a satisfactory contrast ratio.

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: International Publication No. 2010 / 021276 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] Therefore, the present invention is proposed in view of the above problems, and its purpose is to provide an intermediate film structure for sandwich panels and a sandwich panel structure that have a heat-insulating effect and can obtain a sufficient contrast difference between the maximum visible light transmittance and the minimum visible light transmittance when controlling the light transmittance.

[0011] Means for solving problems

[0012] The gist of the present invention is as follows.

[0013] [1] An intermediate film structure for a sandwich panel, which is an intermediate film structure for a sandwich panel used to be arranged between two transparent panels, and comprises a thermoplastic resin sheet and a light-adjusting component sandwiched inside the thermoplastic resin sheet, wherein in a laminated glass produced by bonding two transparent glass plates via the intermediate film structure for laminated glass, the difference in visible light transmittance between the light-adjusting component when driven and when not driven is 20% or more, and the total solar transmittance (Tts) of the light-adjusting component when either driven or not driven is 70% or less.

[0014] [2] The interlayer film structure for a sandwich panel according to [1], wherein the thermoplastic resin sheet includes a heat insulating material.

[0015] [3] The interlayer film structure for a sandwich panel according to [1] or [2], wherein the thermoplastic resin sheet includes a first thermoplastic resin layer and a second thermoplastic resin layer, and the light-adjusting member is disposed between the first thermoplastic resin layer and the second thermoplastic resin layer.

[0016] [4] The interlayer film structure for a sandwich panel according to [3], wherein at least one of the first thermoplastic resin layer and the second thermoplastic resin layer comprises a heat insulating material.

[0017] [5] The interlayer film structure for a sandwich panel according to any one of [1] to [4], wherein the light control member is an electrically controlled light control member.

[0018] [6] A sandwich panel structure comprising two transparent panels and an intermediate film for a sandwich panel arranged between the two transparent panels, wherein the intermediate film for the sandwich panel comprises a thermoplastic resin sheet and a dimming component arranged to be sandwiched inside the thermoplastic resin sheet, wherein the difference in visible light transmittance between the dimming component when driven and when not driven is greater than 20%, and the total sunlight transmittance (Tts) of the dimming component when either driven or not driven is less than 70%.

[0019] Effects of the Invention

[0020] According to the present invention, an interlayer film structure for a sandwich panel and a sandwich panel structure can be provided that have a heat-insulating effect and can achieve a sufficient contrast difference between the maximum visible light transmittance and the minimum visible light transmittance when controlling the light transmittance. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic cross-sectional view (part 1) showing an intermediate film structure for a sandwich panel according to an embodiment of the present invention.

[0022] Figure 2This is a schematic cross-sectional view (part 2) showing an intermediate film structure for a sandwich panel according to an embodiment of the present invention.

[0023] Figure 3 This is a schematic cross-sectional view (part 3) showing an intermediate film structure for a sandwich panel according to an embodiment of the present invention.

[0024] Figure 4 It is a schematic diagram showing the application of the intermediate film structure for a sandwich panel according to an embodiment of the present invention. DETAILED DESCRIPTION

[0025] Hereinafter, the present invention will be described with reference to embodiments.

[0026] <Interlayer film structure for sandwich panels>

[0027] like Figure 1 As shown, an interlayer film structure 1 for a panel (hereinafter also referred to as an "interlayer film structure") according to an embodiment of the present invention is used by being sandwiched between two transparent panels 30 and 31. The interlayer film structure 1 is disposed within a thermoplastic resin sheet. In one embodiment, the thermoplastic resin sheet includes a first thermoplastic resin layer 20 and a second thermoplastic resin layer 21, with the light control member 10 disposed between the first and second thermoplastic resin layers 20, 21. Specifically, the interlayer film structure 1 includes the first thermoplastic resin layer 20 disposed on the transparent panel 30 side, the second thermoplastic resin layer 21 disposed on the transparent panel 31 side, and the light control member 10 disposed between the first and second thermoplastic resin layers 20, 21. The first and second thermoplastic resin layers 20, 21, and the light control member 10 are integrally formed together to form the thermoplastic resin sheet.

[0028] In the sandwich panel, the transparent panel 30 is disposed on the exterior side A, and the transparent panel 31 is disposed on the interior side B. Therefore, the first thermoplastic resin layer 20 is disposed on the exterior side A, and the second thermoplastic resin layer 21 is disposed on the interior side B. For example, when used in a vehicle such as an automobile, the first thermoplastic resin layer 20 is disposed on the exterior side of the vehicle, and the second thermoplastic resin layer 21 is disposed on the interior side of the vehicle.

[0029] [Poor visible light transmittance]

[0030] Regarding the interlayer film structure 1 of the present invention, in a laminated glass produced by bonding two transparent glass sheets together through the interlayer film structure 1, the difference in visible light transmittance between when the light control member 10 is actuated and when it is not actuated is 20% or greater. The difference in visible light transmittance between when the light control member 10 is actuated and when it is not actuated refers to the difference between the maximum visible light transmittance and the minimum visible light transmittance when the light transmittance is controlled by operating the light control member 10 actuated and actuated. If the difference in visible light transmittance is less than 20%, the difference between the maximum visible light transmittance and the minimum visible light transmittance when controlling the light transmittance becomes small, and a satisfactory contrast ratio cannot be achieved.

[0031] From the perspective of maintaining high contrast, the visible light transmittance difference is preferably 15% or more, more preferably 20% or more, and even more preferably 25% or more. Regarding the visible light transmittance difference, the larger the contrast difference, the better, and it can be 75% or less, but is preferably 50% or less for practical purposes.

[0032] The laminated glass produced under the prescribed conditions refers to a sandwich panel structure obtained by bonding two sheets of standard clear glass having a thickness of 2.5 mm via the intermediate film structure 1 under the conditions described in the Examples.

[0033] (Visible light transmittance when the light control member is set to the light transmission mode)

[0034] Regarding the interlayer film structure 1 of the present invention, the visible light transmittance when the dimming element 10 is driven or not driven is referred to as the light transmission mode. Regarding the interlayer film structure 1 of the present invention, in a laminated glass produced by bonding two transparent glass plates together via the interlayer film structure 1, the visible light transmittance measured in the light transmission mode may be higher than 20%, but is preferably 25% or higher, more preferably 30% or higher, and even more preferably 35% or higher.

[0035] Furthermore, the visible light transmittance is preferably 75% or less, more preferably 60% or less, and even more preferably 50% or less.

[0036] When the dimming member 10 is in the light-transmitting mode, the visible light transmittance is increased, making it easier to see outside through the panel structure, making it easier to achieve high contrast compared to the light-blocking mode. Furthermore, since a large amount of external light can enter the interior through the sandwich panel structure, a certain amount of external light can enter even in bad weather or at night, creating a sense of openness even in such environments.

[0037] (Visible light transmittance when the light control member is set to the light shielding mode)

[0038] Regarding the interlayer film structure 1 of the present invention, the mode in which the visible light transmittance is lower when the light control element 10 is driven or not driven is referred to as the light-blocking mode. Regarding the interlayer film structure 1 of the present invention, in laminated glass produced by bonding two transparent glass sheets together via the interlayer film structure 1, the visible light transmittance measured in the light-blocking mode is preferably 5% or less. Furthermore, the visible light transmittance is more preferably 0.1% to 3%, and even more preferably 0.2% to 2%.

[0039] As described above, if the visible light transmittance can be adjusted to 5% or less, the interlayer film structure 1 for sandwich panels can adequately block visible light. For example, when used in automotive window glass, particularly roof glass, it can protect the interior of the vehicle from sunlight. This also helps prevent heat-resistant degradation of the light-adjusting component. Furthermore, if the visible light transmittance is adjusted to 0.1% or more, a certain amount of visible light transmittance prevents complete blocking by the interlayer film structure 1 for sandwich panels, achieving a certain sense of openness.

[0040] [Total Solar Transmittance (Tts)]

[0041] Regarding the interlayer film structure 1 of the present invention, the total solar transmittance (Tts) of laminated glass produced by bonding two transparent glass sheets together via the interlayer film structure 1 is 70% or less. If the total solar transmittance (Tts) exceeds 70%, thermal insulation may decrease, and the effectiveness of suppressing thermal degradation may be reduced. Tts, also known as Total Solar Transmittance, is known as an indicator of thermal insulation performance, with smaller values ​​indicating higher thermal insulation performance.

[0042] The total sunlight transmittance (Tts) is preferably 65% ​​or less, preferably 60% or less, more preferably 55% or less, and even more preferably 50% or less. Regarding the total sunlight transmittance (Tts), from the perspective of improving thermal insulation, the lower the better, and a value of 0% or more is sufficient, but in practical terms, it is preferably 20% or more. The total sunlight transmittance (Tts) referred to here can be within the above range in either the case where the dimming component 10 is driven or not driven, but is preferably within the above range when the dimming component 10 is in the light transmission mode.

[0043] The transparent glass plate used in the measurement of visible light transmittance and total solar transmittance (Tts) had a thickness of 2.5 mm and a visible light transmittance of 90.5% as measured in accordance with JIS R 3106:1998. Furthermore, this transparent glass plate uses the CIE standard illuminant D65 specified in JIS Z 8781-1 (2012), JIS Z 8781-2 (2012), and JIS Z 8781-4 (2013), and a 10° viewing field isochromatic function with a*=-0.6, b*=0.2, and a haze of 0.2% or less. This transparent glass plate is also referred to as reference clear glass.

[0044] [Thermoplastic resin layer]

[0045] As described above, the intermediate film structure 1 includes a thermoplastic resin sheet containing a thermoplastic resin. In one embodiment, the intermediate film structure 1 includes a first thermoplastic resin layer 20 and a second thermoplastic resin layer 21 constituting the thermoplastic resin sheet.

[0046] The first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 are layers containing thermoplastic resin. By containing thermoplastic resin, the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 easily function as adhesive layers, thereby improving adhesion to the light control member 10 and the transparent panels 30 and 31.

[0047] The thermoplastic resin is not particularly limited, and examples thereof include polyvinyl acetal resin, ethylene-vinyl acetate copolymer resin, ionomer resin, polyurethane resin, thermoplastic elastomer, acrylic resin, acrylic-vinyl acetate copolymer resin, polyvinyl alcohol resin, polyolefin resin, polyvinyl acetate resin, and polystyrene resin. By using these resins, adhesion to the light control member 10 and the transparent panels 30 and 31 can be easily ensured.

[0048] In each of the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 , the thermoplastic resin may be used alone or in combination of two or more.

[0049] Among the above, at least one selected from polyvinyl acetal resin and ethylene-vinyl acetate copolymer resin is preferred. In particular, when a plasticizer is used in combination, polyvinyl acetal resin is more preferred from the perspective of exhibiting excellent adhesion to transparent panels 30 and 31 made of glass or the like.

[0050] The resins constituting the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 may be appropriately selected from the resins listed above. The resins constituting the respective thermoplastic resin layers may be different, but are preferably the same. Therefore, the resins constituting the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 are preferably both polyvinyl acetal resins or ethylene-vinyl acetate copolymer resins, and more preferably both polyvinyl acetal resins.

[0051] (Polyvinyl acetal resin)

[0052] The polyvinyl acetal resin is not particularly limited as long as it is a polyvinyl acetal resin obtained by acetalizing polyvinyl alcohol (PVA) with aldehyde.

[0053] The aldehyde is not particularly limited, but generally, aldehydes having 1 to 10 carbon atoms are preferably used. The aldehyde having 1 to 10 carbon atoms is not particularly limited, and examples thereof include n-butyraldehyde, isobutyraldehyde, n-valeraldehyde, 2-ethylbutyraldehyde, n-hexanal, n-octanal, n-nonanal, n-decanal, formaldehyde, acetaldehyde, and benzaldehyde. These aldehydes may be used alone or in combination of two or more.

[0054] Among the above, n-butyraldehyde, n-hexanal, and n-valeraldehyde are preferred, and n-butyraldehyde is more preferred. Therefore, the polyvinyl acetal resin is preferably a polyvinyl butyral resin.

[0055] Polyvinyl alcohol (PVA) is obtained by saponifying polyvinyl esters such as polyvinyl acetate. The degree of saponification of polyvinyl alcohol is generally 70 to 99.9 mol%. Polyvinyl acetal resins can be used alone or in combination of two or more.

[0056] The average degree of polymerization of PVA is preferably 200 or greater, more preferably 500 or greater, even more preferably 1,000 or greater, and even more preferably 1,500 or greater. By setting the average degree of polymerization above the lower limit, the penetration resistance of the sandwich panel structure is enhanced. Furthermore, the average degree of polymerization of PVA is preferably 5,000 or less, more preferably 4,000 or less, even more preferably 3,500 or less, and even more preferably 2,500 or less.

[0057] The average degree of polymerization of polyvinyl alcohol is determined by a method in accordance with JIS K 6726 "Testing methods for polyvinyl alcohol".

[0058] The hydroxyl content of the polyvinyl acetal resin is preferably 15 mol% or more, and preferably 38 mol% or less. By setting the hydroxyl content to 15 mol% or more, the adhesiveness is easily improved, and the penetration resistance of the sandwich panel structure is easily improved. Furthermore, by setting the hydroxyl content to 38 mol% or less, the sandwich panel structure is prevented from becoming too hard. From the perspective of adhesion to the glass sheet, the hydroxyl content is more preferably 20 mol% or more, and more preferably 25 mol% or more. Furthermore, the hydroxyl content is more preferably 35 mol% or less, and more preferably 33 mol% or less.

[0059] When a polyvinyl butyral resin is used as the polyvinyl acetal resin, from the same viewpoint, the hydroxyl group content is 15 mol% or more, preferably 38 mol% or less, more preferably 20 mol% or more, further preferably 25 mol% or more, more preferably 35 mol% or less, and further preferably 33 mol% or less.

[0060] The hydroxyl content of the polyvinyl acetal resin is the molar fraction calculated by dividing the amount of ethylene groups bonded to hydroxyl groups by the total amount of ethylene groups in the main chain, expressed as a percentage. The amount of ethylene groups bonded to hydroxyl groups can be measured, for example, in accordance with JIS K 6728 "Testing methods for polyvinyl butyral."

[0061] The degree of acetalization of the polyvinyl acetal resin is preferably 47 mol% or more, and preferably 85 mol% or less. The degree of acetalization is more preferably 55 mol% or more, and further preferably 60 mol% or more, and further preferably 80 mol% or less, and further preferably 75 mol% or less.

[0062] The term "degree of acetalization" refers to the degree of butyralization when the acetal group is a butyral group and the polyvinyl acetal resin (A) is a polyvinyl butyral resin.

[0063] The degree of acetalization is expressed as a percentage, calculated by subtracting the amount of ethylene groups bonded to hydroxyl groups and ethylene groups bonded to acetyl groups from the total amount of ethylene groups in the main chain, and dividing the value by the total amount of ethylene groups in the main chain. The degree of acetalization (degree of butyralization) can be calculated, for example, from the results of measurement in accordance with JIS K 6728 "Testing methods for polyvinyl butyral."

[0064] The degree of acetylation of the polyvinyl acetal resin is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 10 mol% or less, and even more preferably 2 mol% or less. When the degree of acetylation is below the upper limit, the moisture resistance of the interlayer film structure for a sandwich panel and the sandwich panel structure is enhanced. The degree of acetylation is not particularly limited, but is preferably 0.01 mol% or more, and more preferably 0.1 mol% or more.

[0065] The degree of acetylation is a value expressed as a percentage, which is the molar fraction calculated by dividing the amount of ethylene groups bonded to acetyl groups by the total amount of ethylene groups in the main chain. The amount of ethylene groups bonded to acetyl groups can be measured, for example, in accordance with JIS K 6728 "Testing methods for polyvinyl butyral."

[0066] (ethylene-vinyl acetate copolymer resin)

[0067] The ethylene-vinyl acetate copolymer resin may be a non-crosslinked ethylene-vinyl acetate copolymer resin or a high-temperature crosslinked ethylene-vinyl acetate copolymer resin. Furthermore, the ethylene-vinyl acetate copolymer resin may include a modified ethylene-vinyl acetate resin such as a saponified ethylene-vinyl acetate copolymer or a hydrolyzed ethylene-vinyl acetate copolymer.

[0068] The ethylene-vinyl acetate copolymer resin preferably has a vinyl acetate content of 10 to 50% by mass, more preferably 20 to 40% by mass, as measured in accordance with JIS K 6730 "Test Methods for Ethylene-Vinyl Acetate Resins" or JIS K 6924-2:1997. When the vinyl acetate content is above these lower limits, adhesion to glass is enhanced, and the penetration resistance of the sandwich panel structure is likely to be improved. Furthermore, when the vinyl acetate content is below these upper limits, the fracture strength of the interlayer film structure 1 for a sandwich panel is enhanced, and the impact resistance of the sandwich panel structure is improved.

[0069] (Plasticizer)

[0070] The thermoplastic resin sheet preferably contains a plasticizer. More specifically, it is preferred that both the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 further contain a plasticizer. The inclusion of a plasticizer softens the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21, resulting in a softened interlayer film structure 1 for a sandwich panel. Furthermore, when the interlayer film structure 1 for a sandwich panel is used in a sandwich panel structure, the flexibility of the sandwich panel structure is improved, and penetration resistance is also enhanced. Furthermore, high adhesion to the light control component 10 and the transparent panels 30 and 31 can be achieved.

[0071] When using polyvinyl acetal resin as the thermoplastic resin, it is particularly effective to include a plasticizer in each thermoplastic resin layer. Therefore, the first thermoplastic resin layer 20 more preferably includes a polyvinyl acetal resin and a plasticizer. Furthermore, the second thermoplastic resin layer 21 also more preferably includes a polyvinyl acetal resin and a plasticizer.

[0072] Examples of the plasticizer include organic ester plasticizers such as monobasic organic acid esters and polybasic organic acid esters, and phosphorus-based plasticizers such as organic phosphate plasticizers and organic phosphite plasticizers. Among them, organic ester plasticizers are preferred.

[0073] Examples of organic ester plasticizers include triethylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylhexanoate, triethylene glycol dioctanoate, triethylene glycol di-n-octanoate, triethylene glycol di-n-heptanoate, tetraethylene glycol di-n-heptanoate, tetraethylene glycol di-2-ethylhexanoate, dibutyl sebacate, dioctyl azelate, dibutyl carbitol adipate, ethylene glycol di-2-ethylbutyrate, 1,3-propylene glycol di-2-ethylbutyrate, 1,4-butanediol di-2-ethylbutyrate, 1,2-butanediol di-2-ethylbutyrate, diethylene glycol di-2-ethylbutyrate, and 1,2-butanediol di-2-ethylbutyrate. di-2-ethylbutyrate, diethylene glycol di-2-ethylhexanoate, dipropylene glycol di-2-ethylbutyrate, triethylene glycol di-2-ethylvalerate, tetraethylene glycol di-2-ethylbutyrate, diethylene glycol dicaprate, triethylene glycol di-n-heptanoate, tetraethylene glycol di-n-heptanoate, triethylene glycol di-2-ethylbutyrate, dihexyl adipate, dioctyl adipate, hexylcyclohexyl adipate, diisononyl adipate, heptylnonyl adipate, dibutyl sebacate, oil-modified sebacic acid ester, mixtures of phosphates and adipates, mixed adipates, etc. Examples of mixed adipates include adipates made from two or more alcohols selected from alkyl alcohols having 4 to 9 carbon atoms and cyclic alcohols having 4 to 9 carbon atoms.

[0074] Among the above plasticizers, triethylene glycol di-2-ethylhexanoate (3GO) is particularly suitable.

[0075] The content of plasticizer in each of the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 is not particularly limited, but is preferably 10 parts by mass or more and 100 parts by mass or less relative to 100 parts by mass of the thermoplastic resin. If the content of plasticizer is 10 parts by mass or more, the intermediate film structure 1 becomes moderately soft. Therefore, if the intermediate film structure 1 is used in a sandwich panel structure, the penetration resistance of the sandwich panel structure becomes good. In addition, if the content of plasticizer is 100 parts by mass or less, the plasticizer is prevented from separating from the thermoplastic resin layer. The content of plasticizer is more preferably 20 parts by mass or more, further preferably 30 parts by mass or more, further preferably 35 parts by mass or more, further more preferably 70 parts by mass or less, further preferably 63 parts by mass or less. The content of plasticizer in each of the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 may be the same as or different from each other.

[0076] The first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 each contain a resin, or a resin and a plasticizer as a main component. In the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21, the total amount of the thermoplastic resin and the plasticizer is usually 70% by mass or more, preferably 80% by mass or more and less than 100% by mass, and more preferably 90% by mass or more and less than 100% by mass, based on the total amount of each thermoplastic resin layer.

[0077] (Thermal insulation material)

[0078] The thermoplastic resin sheet preferably includes a thermal insulating material. Specifically, at least one of the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 preferably includes a thermal insulating material. The inclusion of the thermal insulating material in the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 enhances thermal insulation performance, thereby improving the total solar transmittance (Tts). Furthermore, the visible light transmittance in the light transmission mode is prevented from significantly decreasing, thereby improving the visible light transmittance difference. Furthermore, the intermediate film structure 1 is effectively inhibited from thermal degradation. To effectively inhibit the light control component 10 from thermal degradation, it is preferred that at least the first thermoplastic resin layer 20 disposed on the exterior side A contain a thermal insulating material.

[0079] As a thermal insulation material, it is typically a material that can absorb infrared rays with a wavelength of 780nm or more, that is, heat rays. The thermal insulation material is made of an inorganic material, and a thermal insulation material is typically used. As a specific example, particles other than metal oxide particles such as metal oxide particles and lanthanum hexaboride (LaB6) particles can be cited. As metal oxide particles, tin oxide particles such as aluminum-doped tin oxide particles, indium-doped tin oxide particles, antimony-doped tin oxide particles (ATO particles), gallium-doped zinc oxide particles (GZO particles), indium-doped zinc oxide particles (IZO particles), aluminum-doped zinc oxide particles (AZO particles), tin-doped zinc oxide particles and silicon-doped zinc oxide particles, titanium oxide particles such as niobium-doped titanium oxide particles, indium oxide particles such as tin-doped indium oxide particles (ITO particles), sodium-doped tungsten oxide particles, cesium-doped tungsten oxide particles (CWO particles), thallium-doped tungsten oxide particles, rubidium-doped tungsten oxide particles, etc. can be cited. In addition, thermal insulation materials other than the above can be used. The thermal insulation material can be used alone or in combination with two or more.

[0080] Among them, metal oxide particles are preferred due to their high heat shielding function, at least one selected from ATO particles, GZO particles, ITO particles, and CWO particles is more preferred, and ITO particles or CWO particles are further preferred.

[0081] As described above, the first thermoplastic resin layer 20 preferably contains a heat-insulating material. In this case, the content of the heat-insulating material in the first thermoplastic resin layer 21 is not particularly limited, but is, for example, 0.01% to 10% by mass, preferably 0.05% to 5% by mass, and more preferably 0.1% to 3% by mass, based on the total weight of each thermoplastic resin layer. By setting the heat-insulating material content above the lower limit, heating inside a vehicle or a house can be appropriately prevented, and thermal degradation of the light-adjusting component can be suppressed. Furthermore, by setting the content below the upper limit, high contrast can be easily achieved.

[0082] The second thermoplastic resin layer 21 also contains a heat-insulating material. In this case, the content of the heat-insulating material in the second thermoplastic resin layer 21 is not particularly limited, but is, for example, 0.01% to 10% by mass, preferably 0.05% to 5% by mass, and more preferably 0.1% to 3% by mass, based on the total amount of the thermoplastic resin layers. By setting the content of the heat-insulating material to a value above the lower limit, heating inside the vehicle or room can be appropriately prevented. Furthermore, by setting the content below the upper limit, high contrast can be easily achieved.

[0083] When both the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 contain a heat-insulating material, the content of the heat-insulating material in each of the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 may be the same. However, from the perspective of achieving high contrast while appropriately preventing heat-resistant degradation, the content of the heat-insulating material in the first thermoplastic resin layer disposed on the exterior side A is preferably greater than the content in the second thermoplastic resin layer disposed on the interior side B.

[0084] Furthermore, from the viewpoint of achieving high contrast while appropriately preventing thermal degradation, it is also preferred that the first thermoplastic resin layer 20 disposed on the exterior side A contains a heat insulating material, while the second thermoplastic resin layer 20 disposed on the interior side B does not contain a heat insulating material.

[0085] The preferred lower limit of the average particle size of the heat insulating material is 10nm, the more preferred lower limit is 20nm, the preferred upper limit is 100nm, the more preferred upper limit is 80nm, and the further preferred upper limit is 50nm. If the average particle size is above the above-mentioned preferred lower limit, the shielding property of the heat rays can be fully improved. In addition, if the average particle size is below the above-mentioned preferred upper limit, it is not easy to excessively block visible light by the heat insulating material. In addition, "average particle size" represents the volume average particle size. The average particle size can be measured using a particle size distribution measuring device ("UPA-EX150" manufactured by Nikkiso Co., Ltd.) or the like.

[0086] The thermoplastic resin sheet of the present invention, that is, the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 may appropriately contain various additives such as a colorant, an antioxidant, a light stabilizer, an ultraviolet absorber, and an antioxidant in addition to the heat insulating material.

[0087] The thickness of the first thermoplastic resin layer 20 is not particularly limited, and is, for example, 0.05 mm or greater, preferably 0.1 mm or greater, and more preferably 0.2 mm or greater. Furthermore, the thickness of the first thermoplastic resin layer 20 is not particularly limited, and is, for example, 1 mm or less, preferably 0.8 mm or less, and more preferably 0.5 mm or less. By setting the thickness of the first thermoplastic resin layer 20 to be greater than the lower limit, thermal insulation performance is more readily exhibited. Furthermore, by setting the thickness of the first thermoplastic resin layer 20 to be less than the upper limit, the thickness of the interlayer film structure 1 for a sandwich panel is not excessively increased, and sufficient transparent visibility can be achieved in light transmission mode.

[0088] The thickness of the second thermoplastic resin layer 21 is not particularly limited, and is, for example, 0.05 mm or greater, preferably 0.1 mm or greater, and more preferably 0.2 mm or greater. Furthermore, the thickness of the second thermoplastic resin layer 21 is not particularly limited, and is, for example, 1 mm or less, preferably 0.8 mm or less, and more preferably 0.5 mm or less. By setting the thickness of the second thermoplastic resin layer 21 to be greater than the lower limit, thermal insulation performance is more readily exhibited. Furthermore, by setting the thickness of the second thermoplastic resin layer 21 to be less than the upper limit, the thickness of the interlayer film structure 1 for a sandwich panel is not excessively increased, and sufficient transparent visibility can be achieved in light transmission mode.

[0089] Commercially available products may be used for the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 . For example, the “S-LEC Film” series manufactured by Sekisui Chemical Co., Ltd. may be used.

[0090] To further enhance thermal insulation performance, the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 may also be formed as a multilayer structure comprising thermal insulation films made of different materials. For example, when a heat-reflective PET film is used as the thermal insulation film, the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 may be formed by laminating in the order of thermoplastic resin layer / heat-reflective PET film / thermoplastic resin layer.

[0091] The heat-insulating function principle of the heat-insulating film is not particularly limited, but examples thereof include heat-absorbing films and heat-reflecting films.

[0092] As a heat ray absorbing film, a film containing a heat insulating material capable of absorbing infrared rays having a wavelength of 780 nm or more, i.e., heat rays, can be cited. The heat insulating material is made of an inorganic material. As a specific example, particles other than metal oxide particles such as metal oxide particles and lanthanum hexaboride (LaB6) particles can be cited. As metal oxide particles, tin oxide particles such as aluminum-doped tin oxide particles, indium-doped tin oxide particles, antimony-doped tin oxide particles (ATO particles), gallium-doped zinc oxide particles (GZO particles), indium-doped zinc oxide particles (IZO particles), aluminum-doped zinc oxide particles (AZO particles), tin-doped zinc oxide particles, and silicon-doped zinc oxide particles can be cited. Zinc oxide particles such as niobium-doped titanium oxide particles, indium oxide particles such as tin-doped indium oxide particles (ITO particles), sodium-doped tungsten oxide particles, cesium-doped tungsten oxide particles (CWO particles), thallium-doped tungsten oxide particles, rubidium-doped tungsten oxide particles, etc. can be cited. In addition, heat insulating materials other than the above can also be used. The heat insulating material can be used alone or in combination of two or more. Among them, metal oxide particles are preferred due to their high heat shielding function, at least one selected from ATO particles, GZO particles, ITO particles, and CWO particles is more preferred, and ITO particles or CWO particles are further preferred.

[0093] As a heat-reflecting film, any film having suitable infrared reflectivity is sufficient. Examples of the main infrared-reflecting component include films containing Ag, Zn, Ti, Sn, Cr, Nb, Ta, Al, In, ITO, ATO, AZO, GZO, and IZO. These components may be used in the form of metal films or transparent conductive films. Furthermore, these components may be contained in the form of particles within a film or resin. Furthermore, a laminated film may be used, wherein a metal film or transparent conductive film containing the above components as the main component is laminated with a dielectric film. Alternatively, the heat-reflecting layer may be an optical interference film formed by laminating multiple dielectric films. Furthermore, a laminated structure may be formed by laminating layers of layers with different refractive indices.

[0094] The film material of the thermal insulation film is not particularly limited, and includes films selected from polyethylene terephthalate, polyethylene naphthalate, polycarbonate, polymethyl methacrylate, polyethersulfone, nylon, polyarylate, polyethylene, polypropylene, cycloolefin polymer, polystyrene, polyvinylidene fluoride, and films obtained by copolymerization of two or more thereof.

[0095] [Dimming component]

[0096] The dimming component 10 only needs to change the visible light transmittance between when the dimming component is not driven and when it is driven. Preferably, it is a dimming element that uses any of electricity, heat, light, and gas as a control factor, and more preferably, an electrical control factor. The dimming component 10 has a high visible light transmittance in the light transmission mode. In addition, the visible light transmittance of the dimming component 10 in the light shielding mode (light scattering mode) is lower than that in the light transmission mode. In addition, the haze value in the light shielding mode (light scattering mode) is generally higher than that in the light transmission mode.

[0097] As the dimming component 10, there can be cited polymer dispersed liquid crystal (PDLC) film, suspended particle device (SPD) film, electrochromic film, electrophoretic film device, polymer network liquid crystal (PNLC) film, guest-host liquid crystal (GHLC) film, among which PDLC film and SPD film are preferred.

[0098] The dimming member 10 is, for example, Figure 3 As shown, the optical fiber includes a first base film 12 disposed on the first thermoplastic resin layer 20 side, a second base film 13 disposed on the second thermoplastic resin layer 21 side, and a light-adjusting layer 11 provided between the first base film 12 and the second base film 13 .

[0099] As the first base film 12 and the second base film 13, resin films containing resin components such as polyester resins such as polyethylene terephthalate and polyethylene naphthalate, acrylic resins, cellulose derivatives such as triacetyl cellulose (TAC), polyethersulfone (PES) resins, and polyimide resins can be cited. Among them, from the viewpoints of workability and the like, a polyester resin film is preferred, and a polyethylene terephthalate film is more preferred.

[0100] In addition, each of the first base film 12 and the second base film 13 may have an electrode layer provided on the surface on the side of the light control layer 11. As the electrode layer, any conventionally known transparent electrode material can be used without particular limitation, and examples thereof include indium tin oxide (ITO) conductive films, tin oxide conductive films, zinc oxide conductive films, polymer conductive films, and the like. Among them, an ITO conductive film is preferred. A lead-out electrode can be connected to the electrode layer, and a voltage can be applied between the electrode layers via the lead-out electrode.

[0101] <<PDLC film>>

[0102] The light control layer in the PDLC film is, for example, a liquid crystal layer composed of polymer-dispersed liquid crystal. Examples of the polymer-dispersed liquid crystal include a substance called network-type liquid crystal in which a network structure is formed by a polymer in the liquid crystal layer.

[0103] The liquid crystal layer can be formed, for example, by spacers or the like to form a space for filling the liquid crystal inside, and the liquid crystal is filled into this space and sealed, but spacers may not be provided. In addition, as the liquid crystal, it can be any type of liquid crystal, and it can be TN type or STN type. In addition, an alignment film can be appropriately provided between the light control layer and the electrode layer. By providing the alignment film, the PDLC film can also be a reverse type described later.

[0104] Regarding the PDLC film, by applying a voltage between the electrode layers, the alignment state of the liquid crystal layer changes, and light transmission and light scattering are switched. The PDLC film can be either a normal type or a reverse type. The normal type is a type in which if a voltage is applied (voltage ON), it becomes a light transmission mode, and in the case where no voltage is applied (voltage OFF), it becomes a light shielding mode (also called "light scattering mode"). In addition, the reverse type is a type in which it becomes a light transmission mode when no voltage is applied, and becomes a light scattering mode when a voltage is applied.

[0105] ]>As described above, the PDLC film has high visible light transmittance and low haze in light transmission mode. Specifically, the visible light transmittance of the PDLC film in light transmission mode is, for example, 60% or higher, preferably 70% or higher, and more preferably 75% or higher. This visible light transmittance significantly improves the light transmittance of the sandwich panel structure in light transmission mode, enabling a sufficiently open feel when used in, for example, automotive roof glass.

[0106] Furthermore, the haze value of the PDLC film in the light transmission mode is, for example, 30% or less, preferably 20% or less, and more preferably 10% or less.

[0107] The visible light transmittance of the PDLC film in the light transmission mode only needs to be 100% or less, but is practically 99% or less. The haze value only needs to be 0% or more, but is practically 1% or more, for example.

[0108] On the other hand, in the light-shielding mode (light-scattering mode), the haze value of the PDLC film is, for example, 70% or greater, preferably 80% or greater, and more preferably 90% or greater. In the light-scattering mode, a higher haze value enhances light-shielding properties, and in the light-scattering mode, it is possible to appropriately prevent the influx of heat rays. Furthermore, when used as a screen, sufficient image clarity can be achieved.

[0109] Furthermore, in light-scattering mode, the visible light transmittance of the PDLC film is lower than in light-transmitting mode, for example, 40% or less, preferably 20% or less, and more preferably 10% or less. As described above, the reduced light transmittance in light-scattering mode effectively prevents the influx of heat rays in light-scattering mode. Furthermore, when used as a screen, sufficient image clarity can be achieved.

[0110] In addition, the haze value of the PDLC film in the light scattering mode can be 100% or less, but is practically about 99% or less. In addition, the visible light transmittance can be 0% or more, but is practically about 1% or more.

[0111] Furthermore, the PDLC film can be in either a light-scattering mode or a light-transmitting mode when no voltage is applied, as long as the haze value and visible light transmittance are within the above-mentioned ranges in that mode. Furthermore, the PDLC film can be in either a light-scattering mode or a light-transmitting mode when a voltage is applied, as long as the haze value and visible light transmittance are within the above-mentioned ranges in that mode. However, the applied voltage value is not limited; as long as the haze value and visible light transmittance are within the above-mentioned ranges at a certain voltage value, the PDLC film can be in the other of the light-scattering mode and the light-transmitting mode when a voltage is applied.

[0112] In addition, the visible light transmittance of the PDLC film can be measured using a spectrophotometer in accordance with JIS R 3106:2019. Furthermore, the haze value can be measured using a haze meter (e.g., "TC-HIIIDPK" manufactured by Tokyo Denshoku Co., Ltd.) in accordance with JIS K 6714.

[0113] The thickness of the PDLC film is not particularly limited, for example, it is 0.05 mm or more and 2 mm or less, preferably 0.1 mm or more and 1 mm or less, and more preferably 0.2 mm or more and 0.8 mm or less.

[0114] Commercially available products can be used for the PDLC film. Specifically, examples include the normal type of the "LC MAGIC" series manufactured by Toppan Printing Co., Ltd. [Light transmission mode: haze value 5%, parallel line transmittance 82%, light scattering mode: haze value 98%, parallel line transmittance 1% (catalog value)], the reverse type [Light transmission mode: haze value 10%, parallel line transmittance 80%, light scattering mode: haze value 92%, parallel line transmittance 7% (catalog value)]. Furthermore, examples include the window type of "UMU" manufactured by NSG UMU PRODUCTS Co., Ltd. of Japan [Light transmission mode: haze value 6%, parallel line transmittance 74%, light scattering mode: haze value 86%, parallel line transmittance 5% (catalog value)], etc. In addition, examples include "LC-W" of Gauzy Co., Ltd.

[0115] <<SPD film>>

[0116] The light control layer in the SPD (Suspended Particle Device) film is a layer containing a resin matrix and a light control suspension dispersed in the resin matrix. The resin matrix is made of a polymer medium, and the light control suspension is obtained by dispersing light control particles in a dispersing medium in a flowable state. As the polymer medium and the dispersing medium (the dispersing medium in the light control suspension), substances that can be separated from each other at least during film formation are used for the polymer medium and its cured product and the dispersing medium. It is preferable to use a polymer medium and a dispersing medium that are incompatible or partially compatible with each other in combination.

[0117] The polymer medium contains a resin having a substituent containing an ethylenic unsaturated bond and a photoinitiator, and examples include substances that are cured by irradiating energy rays such as ultraviolet rays, visible light rays, and electron rays. As the resin containing an ethylenic unsaturated bond, silicone-based resins, acrylic resins, polyester resins, etc. are preferred.

[0118] In addition, in addition to the above-mentioned resin having a substituent containing an ethylenic unsaturated bond, an organic solvent-soluble resin or a thermoplastic resin can be used in combination. For example, polyacrylic acid, polymethacrylic acid, etc. are used as the constituent materials of the polymer medium.

[0119] Furthermore, additives such as anti-coloring agents such as dibutyltin dilaurate may be added to the polymer medium as needed. Furthermore, the polymer medium may also contain a solvent.

[0120] As the dispersion medium in the light-adjusting suspension, it is preferred to use a liquid copolymer that plays the role of a dispersion medium in the light-adjusting suspension, selectively adheres to and coats the light-adjusting particles, and acts in a manner such that the light-adjusting particles move toward the phase-separated droplet phase when phase-separated from the polymer medium. It has no conductivity and no affinity with the polymer medium.

[0121] As the liquid copolymer, for example, a (meth)acrylate oligomer having a fluorine group and / or a hydroxyl group is preferable, and a (meth)acrylate oligomer having a fluorine group and a hydroxyl group is more preferable.

[0122] The light-adjusting suspension used in the present invention is obtained by fluidly dispersing light-adjusting particles in a dispersion medium. As the light-adjusting particles, for example, polyiodide crystals are used, preferably small needle-shaped polyiodide crystals.

[0123] In the SPD film, when a voltage is applied between two electrode layers, the light-regulating particles are oriented in the thickness direction, thereby increasing light transmittance, for example, transmittance in a specific wavelength range.

[0124] Furthermore, in the SPD film, a primer layer may be appropriately provided between the light-adjusting layer and the electrode layer.

[0125] Regarding the SPD film, if no voltage is applied between the electrode layers (voltage OFF), the light transmittance is low, and the film enters the light-blocking mode. On the other hand, if a voltage is applied between the electrode layers (voltage ON), the transmittance in a specific wavelength range, for example, increases, thereby switching from the light-blocking mode to the light-transmitting mode. Regarding the SPD film, as the visible light transmittance changes, the color tone when irradiated with visible light can also change. For example, it can be made colorless and transparent when a voltage is applied, and on the other hand, it can have a blue color tone when no voltage is applied. In addition, if the voltage value applied between the electrodes of the SPD film is changed, the visible light transmittance in the light-transmitting mode also changes.

[0126] Commercially available SPD films can be used. Specifically, examples include Hitachi Chemical Co., Ltd.'s "LCF-1103DHA" Light type [Light transmission mode: visible light transmittance 45-65% (50-100V), haze value 6%, light shielding mode: visible light transmittance 3% (catalog value)] and Dark type [Light transmission mode: visible light transmittance 30-53% (50-100V), haze value 6%, light shielding mode: visible light transmittance 1% (catalog value)]. Another example of an SPD film is Gauzy's "SPD."

[0127] <<Electrochromic Film>>

[0128] The light-adjusting layer in the electrochromic film may contain an electrochromic material. The electrochromic material is not limited as long as it is a compound having electrochromic properties, and may be any of an inorganic compound, an organic compound, and a mixed valence coordination compound.

[0129] Examples of inorganic compounds include Mo2O3, Ir2O3, NiO, V2O5, WO3, and TiO2, with WO3 being preferred. Examples of organic compounds include polypyrrole compounds, polythiophene compounds, polyparaphenylene vinylene compounds, polyaniline compounds, polyacetylene compounds, polyethylenedioxythiophene compounds, metal phthalocyanine compounds, viologen compounds, viologen salt compounds, ferrocene compounds, dimethyl terephthalate compounds, and diethyl terephthalate compounds, with polyacetylene compounds being preferred. Furthermore, examples of mixed-valence coordination compounds include Prussian blue-type coordination compounds (e.g., KFe[Fe(CN)6]).

[0130] With electrochromic films, applying a voltage between electrode layers changes the transmittance in a specific wavelength range, for example, thereby shifting the light-adjusting element from a state with high visible light transmittance (light-transmitting mode) to a state with low visible light transmittance (light-blocking mode). Furthermore, the color tone of the film can also be changed when irradiated with visible light. For example, it can be made colorless and transparent when no voltage is applied, while being given a blue, yellow, green, or red hue when a voltage is applied.

[0131] The thickness of the electrochromic film is not particularly limited, and is, for example, 0.05 mm to 2 mm, preferably 0.1 mm to 1 mm, and more preferably 0.2 mm to 0.8 mm.

[0132] A commercially available electrochromic film can be used, and specific examples thereof include electrochromic films from Ynvisible.

[0133] <<Electrophoretic membrane devices>>

[0134] An electrophoretic film device has an electrophoretic portion, for example, between two substrates each having an electrode layer. The electrophoretic portion includes, for example, electrophoretic particles and a dispersant for dispersing the electrophoretic particles. In the electrophoretic film device, it is also possible to change between a state with a high visible light transmittance (light transmission mode) and a state with a low visible light transmittance (light shielding mode) by changing whether or not a voltage is applied between the electrode layers. Specific examples of the electrophoretic film device are described in detail in U.S. Patent Publication No. 2016 / 0124284 and the like.

[0135] The thickness of the electrophoretic film device is not particularly limited, and is, for example, 0.05 mm or more and 2 mm or less, preferably 0.1 mm or more and 1 mm or less, and more preferably 0.2 mm or more and 0.8 mm or less.

[0136] Commercially available products can be used for the electrophoretic film device. Specific examples include "E-Skin" of Signify Corporation.

[0137] <<PNLC film>>

[0138] In a polymer network liquid crystal film, the light modulating layer is a polymer network liquid crystal layer disposed between two films.

[0139] In the PNLC film, when a voltage is applied between the electrode layers, the alignment state of the liquid crystal layer changes, and light transmission and light scattering are switched. The PNLC film can be either a normally type or a reverse type. The normally type is a type that becomes the light transmission mode when a voltage is applied (voltage ON) and becomes the light shielding mode (also referred to as "light scattering mode") when no voltage is applied (voltage OFF). In addition, the reverse type is a type that becomes the light transmission mode when no voltage is applied and becomes the light scattering mode when a voltage is applied.

[0140] The thickness of the PNLC film is not particularly limited, and is, for example, 0.05 mm or more and 2 mm or less, preferably 0.1 mm or more and 1 mm or less, and more preferably 0.2 mm or more and 0.8 mm or less.

[0141] Commercially available products can be used for the PNLC film. Specific examples include the reverse type of the "LC MAGIC" series manufactured by Toppan Printing Co., Ltd.

[0142] <<GHLC film>>

[0143] The light modulating layer in the GHLC film is composed of a dichroic pigment (guest) and a liquid crystal (host). Since the dichroic pigment has different light absorption degrees depending on the axial direction, it is possible to generate a transmission state and a light shielding state following the movement of the liquid crystal.

[0144] The thickness of the GHLC film is not particularly limited, and is, for example, 0.05 mm to 2 mm, preferably 0.1 mm to 1 mm, and more preferably 0.2 mm to 0.8 mm.

[0145] [switch]

[0146] The interlayer film structure 1 for a sandwich panel may include a switch component (not shown). The switch component is used to control the dimming component 10. The switch component controls whether a voltage is applied between the electrode layers of the dimming component 10 through a switch input. This allows the switch component to switch the dimming component 10 between a light-transmitting mode and a light-blocking mode.

[0147] The switch member may be disposed outside the interlayer film structure 1 for sandwich panels, but is preferably constituted by a touch sensor disposed inside the interlayer film structure 1 for sandwich panels. Therefore, the light control member 10 is preferably controlled by the touch sensor.

[0148] In the above description, the light adjusting component is described based on the premise that it is composed of one structure, but the light adjusting component can also be provided with two or more. Figure 2 As shown, two light control members can be arranged in the thickness direction. When two light control members 10A and 10B are arranged in the thickness direction, a third thermoplastic resin layer 22 can be further arranged between the two light control members 10A and 10B, and the two light control members 10A and 10B can be bonded via the third thermoplastic resin layer 22. Alternatively, the first thermoplastic resin layer 20 can be arranged on the outer side of the light control member 10A, and the second thermoplastic resin layer 21 can be arranged on the outer side of the light control member 10B.

[0149] In addition, as a structure in which two or more dimming components are provided, not only Figure 2 The structure shown as being arranged in the thickness direction may also include two or more light-adjusting members arranged in the width direction (in the same plane). In addition, a light-adjusting member may be processed into sections within one plane to function as two or more light-adjusting members.

[0150] The details of the first and second thermoplastic resin layers 20 and 21 are as described above. The third thermoplastic resin layer 22, like the first and second thermoplastic resin layers 20 and 21, is a layer comprising a thermoplastic resin. Its details are similar to those of the second thermoplastic resin layer 21, and therefore, its description is omitted. Furthermore, like the second thermoplastic resin layer 21, the third thermoplastic resin layer 22 preferably contains a plasticizer and may or may not contain a heat insulating material. Its details are also similar to those of the second thermoplastic resin layer 21.

[0151] Furthermore, when multiple light-adjusting members are provided, three or more light-adjusting members may be provided. In this case, a thermoplastic resin sheet may be provided between each light-adjusting member. In this case, the thermoplastic resin layer provided between each light-adjusting member is the same as the third thermoplastic resin layer described above.

[0152] In addition, Figure 1 The figure schematically illustrates a configuration in which the light-adjusting member is provided throughout the entire area of ​​the intermediate film structure 1. However, it need not be provided throughout the entire area and may be provided in a portion of the area. For example, the light-adjusting member 10 may not be provided at the outer edge. In this case, the first and second thermoplastic resin layers 20 and 21 may be directly bonded to the portion where the light-adjusting member 10 is not provided. Alternatively, a ring-shaped or frame-shaped thermoplastic resin sheet, such as one surrounding the light-adjusting member 10, may be arranged on the outer periphery of the light-adjusting member 10. In this case, the first and second thermoplastic resin layers 20 and 21 may be bonded to the outer peripheral thermoplastic resin layer. Furthermore, when the light-adjusting member 10 is provided in a portion of the area, the visible light transmittance and total solar transmittance (Tts) in the area where the light-adjusting member is provided can be measured.

[0153] In addition, the light control member 10 is "driven" and "non-driven", and the intermediate film structure 1 of the present invention is as follows: Figure 2 As shown, when there are multiple dimming components 10A and 10B, any of the dimming components 10A and 10B that can be switched to be driven can be used. Therefore, when any one or more of the multiple dimming components 10A and 10B switches between driving and non-driving, it is sufficient as long as the visible light transmittance difference is within the above range. In addition, any one or more of the dimming components 10A and 10B can be within the above range of the total sunlight transmittance (Tts) when driving or non-driving. Preferably, the total sunlight transmittance (Tts) is within the above range in the light transmission mode.

[0154] [Adhesive layer]

[0155] The interlayer film structure 1 for a sandwich panel may include an adhesive layer (not shown) provided between, for example, the first thermoplastic resin layer 20 and the light-adjusting member 10, or between the second thermoplastic resin layer 21 and the light-adjusting member 10, with the light-adjusting member 10 bonded to at least one of the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 via the adhesive layer. However, it is preferred that no adhesive layer be provided between them, and that the light-adjusting member 10 be directly bonded to the first thermoplastic resin layer 20. Similarly, it is preferred that the light-adjusting member 10 be directly bonded to the second thermoplastic resin layer 21.

[0156] Furthermore, the interlayer film structure 1 for a sandwich panel may include, for example, an adhesive layer provided on the outside of at least one of the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21, with at least one of the first thermoplastic resin layer 20 and the second thermoplastic resin layer 21 being bonded to the transparent panels 30 and 31 via the adhesive layer. However, it is preferred that no adhesive layer be provided on the outside of the first thermoplastic resin layer 20, with the first thermoplastic resin layer 20 being directly bonded to the transparent panel 30. Similarly, it is preferred that no adhesive layer be provided on the outside of the second thermoplastic resin layer 21, with the second thermoplastic resin layer 21 being directly bonded to the transparent panel 31.

[0157] Furthermore, when two or more light-adjusting components are provided, as described above, a thermoplastic resin sheet may be further provided between the light-adjusting components. The thermoplastic resin sheet may be directly bonded to the light-adjusting components or bonded via another layer such as an adhesive layer. The adhesive layer is not particularly limited and may be composed of a known material, for example, the aforementioned thermoplastic resin.

[0158] (Method for producing an intermediate film structure)

[0159] In the present invention, in the production of the intermediate film structure, first, a light control member and resin films for forming each thermoplastic resin layer are prepared.

[0160] Then, the light-adjusting member can be appropriately overlapped with the resin film. Figure 1 As shown, when there is one dimming member, two resin films can be prepared and stacked in the order of resin film / dimming member / resin film. Alternatively, when there are two dimming members, three resin films can be prepared and stacked in the order of resin film / dimming member / resin film / dimming member / resin film. Similarly, when there are three or more dimming members, the resin films / dimming members can be stacked alternately.

[0161] When an adhesive layer is provided between the light-adjusting member and the thermoplastic resin layer or on the surface of the intermediate film structure, resin films for forming the adhesive layer may be prepared and appropriately laminated.

[0162] As described above, the laminated body obtained by laminating the light control member and the resin film can be produced by, for example, applying pressure in the thickness direction or thermocompression bonding under negative pressure to produce an intermediate film structure.

[0163] <Sandwich Panel Structure>

[0164] like Figure 1As shown, the sandwich panel structure 100 of the present invention includes the above-mentioned intermediate film structure 1 and two transparent panels 30, 31, with the intermediate film structure 1 being sandwiched between the two transparent panels 30, 31. In the sandwich panel structure 100, the two transparent panels 30, 31 are bonded together via the intermediate film structure 1. The configuration of each component of the intermediate film structure 1 is as described above.

[0165] Examples of the transparent panels 30 and 31 include glass plates. The glass plates may be either inorganic glass or organic glass, but inorganic glass is preferred. Inorganic glass is not particularly limited, and examples thereof include clear glass, clear float glass, float flat glass, tempered glass, tinted glass, polished flat glass, patterned flat glass, wired flat glass, wired flat glass, ultraviolet absorbing flat glass, infrared reflecting flat glass, infrared absorbing flat glass, green glass, and low-reflection glass.

[0166] As the organic glass, what is generally called resin glass is used. Although not particularly limited, examples thereof include organic glass made of a polycarbonate plate, a polymethyl methacrylate plate, a polyester plate, and the like.

[0167] From the viewpoint of obtaining a satisfactory contrast difference, the two transparent panels 30 and 31 are preferably made of a material with high visible light transmittance, for example, transparent glass.

[0168] Furthermore, from the perspective of heat insulation, either of the two transparent panels 30 and 31 can be made of either infrared-reflecting flat glass or infrared-absorbing flat glass. However, in this case, the transparent panel 30 on the vehicle's exterior is preferably made of either infrared-reflecting flat glass or infrared-absorbing flat glass. Furthermore, it is more preferable that the transparent panel 30 on the vehicle's exterior be made of either infrared-reflecting flat glass or infrared-absorbing flat glass, while the transparent panel 31 on the vehicle's interior be made of transparent glass. By making the transparent panel 30 on the vehicle's exterior be made of either infrared-reflecting flat glass or infrared-absorbing flat glass, thermal degradation of the light-adjusting component can be more effectively prevented.

[0169] The two transparent panels 30 and 31 can be made of the same material or different materials. For example, one can be inorganic glass and the other organic glass. Preferably, both transparent panels 30 and 31 are inorganic glass or organic glass, and more preferably, both are inorganic glass.

[0170] The thickness of each of the transparent panels 30 and 31 is not particularly limited, but is preferably 0.5 mm to 3.2 mm, more preferably 0.7 mm to 2.7 mm, and even more preferably 1.0 mm to 2.6 mm. By remaining within the above range, the sandwich panel structure 100 can be given a certain mechanical strength while keeping the overall thickness of the sandwich panel structure below a certain value.

[0171] The sandwich panel structure 100 of the present invention preferably has a thickness of 7 mm or less. By having a thickness of 7 mm or less, it is suitable for use in automotive window glass, particularly automotive roof glass. The lower limit of the thickness of the sandwich panel structure is not particularly limited, but is, for example, 4 mm or greater, preferably 5 mm or greater.

[0172] [Poor visible light transmittance of sandwich panel structure]

[0173] In the sandwich panel structure 100 of the present invention, the difference in visible light transmittance between the dimming member 10 when it is driven and when it is not driven is 20% or greater. The difference in visible light transmittance between the dimming member 10 when it is driven and when it is not driven refers to the difference between the maximum visible light transmittance and the minimum visible light transmittance when the dimming member 10 is driven and when it is not driven, thereby controlling the transmittance of light. If the difference in visible light transmittance is less than 20%, the difference between the maximum visible light transmittance and the minimum visible light transmittance when controlling the transmittance of light becomes small, and a satisfactory contrast ratio cannot be achieved.

[0174] From the perspective of maintaining high contrast, the visible light transmittance difference is preferably 25% or more, more preferably 30% or more, and even more preferably 35% or more. Regarding the visible light transmittance difference, the larger the contrast difference, the better, as long as it is 75% or less, but for practical purposes, it is preferably 50% or less.

[0175] (Visible light transmittance when the light control member is set to the light transmission mode)

[0176] Regarding the sandwich panel structure 100 of the present invention, the mode in which the visible light transmittance is higher, when the dimming member 10 is driven or when it is not driven, is referred to as the light transmission mode. In a laminated glass produced by bonding two transparent glass sheets 30 and 31 together via the intermediate film structure 1 in the sandwich panel structure 100 of the present invention, the visible light transmittance measured in the light transmission mode may be higher than 20%, but is preferably higher than 25%, more preferably higher than 30%, and even more preferably higher than 35%.

[0177] Furthermore, the visible light transmittance is preferably 75% or less, more preferably 60% or less, and even more preferably 50% or less.

[0178] When the light-adjusting member 10 is in the light-transmitting mode, the high visible light transmittance allows easy viewing of the exterior through the sandwich panel structure, making it easier to achieve high contrast compared to the light-blocking mode. Furthermore, since a significant amount of external light can enter the interior through the sandwich panel structure, a certain amount of external light can enter even in bad weather or at night, providing a sense of openness even in such environments.

[0179] (Visible light transmittance when the light control member is set to the light shielding mode)

[0180] Regarding the sandwich panel structure 100 of the present invention, the mode in which the visible light transmittance is lower when the light control member 10 is driven than when it is not driven is referred to as the light blocking mode. In a laminated glass produced by bonding two transparent glass sheets 30 and 31 together via the intermediate film structure 1, the sandwich panel structure 100 of the present invention preferably has a visible light transmittance of 5% or less measured in the light blocking mode. Furthermore, this visible light transmittance is more preferably 0.1% to 3%, and even more preferably 0.2% to 2%.

[0181] As described above, if the visible light transmittance can be adjusted to 5% or less, the interlayer film structure 1 for sandwich panels can effectively block visible light. For example, when used in automotive window glass, particularly roof glass, it can prevent sunlight from irradiating the interior of the vehicle. This also makes it easier to prevent heat-resistant degradation of the light-adjusting component. Furthermore, if the visible light transmittance is adjusted to 0.1% or more, a certain amount of visible light is transmitted, preventing complete blocking by the interlayer film structure 1 for sandwich panels and achieving a certain sense of openness.

[0182] [Total Solar Transmittance (Tts) of Sandwich Panel Structure]

[0183] The sandwich panel structure 100 of the present invention has a total solar transmittance (Tts) of 70% or less. If Tts exceeds 70%, thermal insulation properties decrease, reducing the effectiveness of suppressing thermal degradation. Tts, also known as Total Solar Transmittance, is known as an indicator of thermal insulation, with lower values ​​indicating higher thermal insulation properties.

[0184] The total sunlight transmittance (Tts) is preferably 65% ​​or less, preferably 60% or less, more preferably 55% or less, and even more preferably 50% or less. From the perspective of improving thermal insulation, the lower the total sunlight transmittance (Tts), the better, as long as it is 0% or more, but in practical terms, it is preferably 5% or more. The total sunlight transmittance (Tts) here refers to the range when the dimming component 10 is driven or not driven, but it is preferably within the range when the dimming component 10 is in the light transmission mode.

[0185] (Method for manufacturing a sandwich panel structure)

[0186] The method for producing the sandwich panel structure is not particularly limited. For example, the sandwich panel structure can be obtained by placing the intermediate film structure between two transparent panels and bonding them by thermocompression using an autoclave or the like.

[0187] Furthermore, in the present invention, the sandwich panel structure can be manufactured simultaneously with the formation of the intermediate film structure. Specifically, the light-adjusting member and the resin film used for the thermoplastic resin layer can be appropriately overlapped, and the resulting laminated body can be placed between two transparent panels and then heat-pressed using an autoclave or the like, thereby simultaneously forming the intermediate film structure and obtaining the sandwich panel structure.

[0188] [use]

[0189] The interlayer film structure 1 and the sandwich panel structure 100 of the present invention can be used for window glasses of various vehicles such as automobiles, aircraft, ships, buildings, and the like, but are preferably used for vehicles.

[0190] In a motor vehicle, heat may flow from outside into the vehicle through the window glass, causing the interior to heat up. Similarly, in a building, heat may flow into the building through the window glass, causing the interior to heat up. However, since the interlayer film structure 1 of the present invention has a total solar transmittance (Tts), particularly a total solar transmittance (Tts) in the light transmission mode, below a specified value as described above, it can prevent the interior of a vehicle or building from heating up.

[0191] Furthermore, when a light modulator is used as the light modulating means, by setting the light modulator to the light shielding mode to shield light, it is possible to further appropriately prevent heat rays from flowing into the interior of a vehicle or a building.

[0192] On the other hand, by setting the light control member to the light transmission mode, the visible light transmittance is increased, so that the outside can be easily seen through the panel structure, and high contrast can be easily achieved compared to the light shielding mode.

[0193] Furthermore, the interlayer film structure 1 and the interlayer film structure 100 for sandwich panels of the present invention are particularly preferably used for automotive applications. When used for automotive applications, they can be used for any window glass such as side glass, rear glass, and roof glass. Figure 4 As shown, it is preferably used as a roof glass in a roof (ceiling) portion 111 of an automobile 110. The interlayer film structure 1 and the sandwich panel structure 100 of the present invention can be used for a roof glass to more easily provide a sense of openness.

[0194] Furthermore, roof glass only needs to be at least partially located on the roof. For example, glass located across the roof and rear of the vehicle is also considered roof glass. Furthermore, the roof of a motor vehicle constitutes the top surface of the vehicle body, and roof glass is generally located horizontally or slightly tilted (for example, within 20°) relative to the horizontal. The tilt is the inclination of a straight line connecting the ends of the glass located on the roof relative to the horizontal.

[0195] In addition, the roof glass has a thickness of, for example, 0.5 mm 2 More than 1m, preferably 2 More than 1.5m 2 The area above.

[0196] The interlayer film structure 1 for a sandwich panel and the sandwich panel structure 100 of the present invention can be used by appropriately adjusting the visible light transmittance by appropriately switching the light transmission mode and the light shielding mode of the light control member 10 .

[0197] For example, if you want to block external light, you can set the light control member 10 to the light blocking mode. On the other hand, if you want to see the outside through the sandwich panel structure 100 or want a sense of openness, you can set the light control member 10 to the light transmitting mode.

[0198] Example

[0199] The present invention will be described in further detail using examples, but the present invention is not limited to these examples.

[0200] <Measurement Method>

[0201] The visible light transmittance of the sandwich panel structure was measured by the following method.

[0202] [Visible light transmittance]

[0203] The measurement was performed using a spectrophotometer (manufactured by Hitachi High-Technologies Corporation, trade name “U-4100”) in accordance with JIS R 3106:2019.

[0204] [Total Solar Transmittance (Tts)]

[0205] Total solar transmittance (Tts: Total Solar Transmittance) was measured using a spectrophotometer ("U-4100" manufactured by Hitachi High-Technologies Corporation) in accordance with ISO 13837. The measurement conditions were a scanning speed of 300 nm / min and a slit width of 8 nm.

[0206] <Evaluation Method>

[0207] [Contrast difference]

[0208] The sandwich panel structures obtained in Examples and Comparative Examples were evaluated according to the following criteria.

[0209] A: The difference in visible light transmittance between when the dimming component is driven and when it is not driven is 50% or more

[0210] B: The difference in visible light transmittance between when the dimming member is driven and when it is not driven is 25% or more and less than 50%

[0211] C: The difference in visible light transmittance between the dimming component when it is driven and when it is not driven is less than 25%

[0212] [Example 1]

[0213] First, prepare the following materials.

[0214] Resin film for the first thermoplastic resin layer: A thermal insulation resin film 1 composed of 100 parts by mass of polyvinyl butyral resin (hydroxyl content 30.5 mol%, acetalization degree 68.5 mol%, acetylation degree 1 mol%, average polymerization degree 1,700), 40 parts by mass of triethylene glycol di-2-ethylhexanoate (3GO), and 0.5 parts by mass of tin-doped indium oxide particles (average particle size: 50 nm), with a thickness of 0.76 mm.

[0215] Resin film for the second thermoplastic resin layer: A transparent resin film 1 composed of 100 parts by mass of polyvinyl butyral resin (hydroxyl content 30.5 mol%, acetalization degree 68.5 mol%, acetylation degree 1 mol%, average polymerization degree 1,700) and 40 parts by mass of triethylene glycol di-2-ethylhexanoate (3GO), with a thickness of 0.76 mm.

[0216] Light-adjusting member: Polymer dispersed liquid crystal film (manufactured by Gauzy, trade name "LC-W"), light-shielding mode when voltage is OFF, light-transmitting mode when voltage is ON (70V), thickness 0.38 mm

[0217] ·1st transparent panel: Standard transparent glass as specified in the manual, thickness 2.5mm

[0218] Second transparent panel: Standard transparent glass as specified in the manual, 2.5mm thick

[0219] The resin film for the first thermoplastic resin layer, the dimming component, and the resin film for the second thermoplastic resin layer are stacked in sequence and heat-pressed at 70°C and -780mbar (gauge pressure) to integrate them, thereby obtaining an intermediate film structure for a sandwich panel. Next, the intermediate film structure for a sandwich panel obtained is stacked on a transparent panel, and another transparent panel is integrated under the conditions of 90°C and 3bar (gauge pressure) using an autoclave to obtain a sandwich panel structure. The sandwich panel structure is as follows. Figure 1 As shown, it has a laminated structure of first transparent panel / first thermoplastic resin layer / dim-adjusting member / second thermoplastic resin layer / second transparent panel.

[0220] [Example 2]

[0221] The same materials as in Example 1 were used except that the first thermoplastic resin layer was changed to the following material.

[0222] Resin film of the first thermoplastic resin layer: A multilayer thermal insulating resin film 2 having a thickness of 0.9 mm, which is formed by laminating a resin film composed of 100 parts by mass of a polyvinyl butyral resin (hydroxyl content 30.5 mol%, acetalization degree 68.5 mol%, acetylation degree 1 mol%, average polymerization degree 1,700) and 40 parts by mass of triethylene glycol di-2-ethylhexanoate (3GO); a heat-reflecting film (manufactured by 3M, Nano80S); and a thermal insulating resin film composed of 100 parts by mass of a polyvinyl butyral resin (hydroxyl content 30.5 mol%, acetalization degree 68.5 mol%, acetylation degree 1 mol%, average polymerization degree 1,700), 40 parts by mass of triethylene glycol di-2-ethylhexanoate (3GO); and 0.5 parts by mass of tin-doped indium oxide particles (average particle size: 50 nm) in this order.

[0223] [Example 3]

[0224] The same materials as in Example 1 were used except that the light control member was changed to the following material.

[0225] Light-adjusting component: Suspended particle device film (Showa Denko K.K., trade name "LCF-1103DHA"), light-shielding mode when voltage is OFF, light-transmitting mode when voltage is ON (100 V), thickness 0.4 mm

[0226] [Example 4]

[0227] The same materials as in Example 1 were used except that the first thermoplastic resin layer and the light-adjusting member were changed to the following materials.

[0228] Resin film of the first thermoplastic resin layer: Multilayer thermal insulation resin film 2, thickness 0.76 mm

[0229] Light-adjusting component: Suspended particle device film (Showa Denko K.K., trade name "LCF-1103DHA"), light-shielding mode when voltage is OFF, light-transmitting mode when voltage is ON (100V), thickness 0.4 mm

[0230] [Comparative Example 1]

[0231] The same materials as in Example 1 were used except that the first thermoplastic resin layer, the first transparent panel, and the second transparent panel were changed to the following materials.

[0232] Resin film for the first thermoplastic resin layer: transparent resin film 1

[0233] ·1st transparent panel: infrared reflective flat glass, 2.5mm thick

[0234] Second transparent panel: Low-E glass, 2.5mm thick

[0235] [Comparative Example 2]

[0236] The same materials as in Example 1 were used except that the first thermoplastic resin layer, the light control member, the first transparent panel, and the second transparent panel were changed to the following materials.

[0237] Resin film for the first thermoplastic resin layer: transparent resin film 1

[0238] Light-adjusting component: Suspended particle device film (Showa Denko K.K., trade name "LCF-1103DHA"), light-shielding mode when voltage is OFF, light-transmitting mode when voltage is ON (100V), thickness 0.4 mm

[0239] ·1st transparent panel: infrared reflective flat glass, 2.5mm thick

[0240] Second transparent panel: Low-E glass, 2.5mm thick

[0241]

[0242] As shown in Table 1, regarding the sandwich panel structures of Examples 1 to 4, since the conditions are met that the difference in visible light transmittance when the dimming component is driven and when it is not driven is more than 20%, and the total sunlight transmittance (Tts) of the dimming component is less than 70% in any of the times when it is driven and when it is not driven, while having a heat insulating effect, a sufficient contrast difference between the maximum visible light transmittance and the minimum visible light transmittance when controlling the light transmittance can be obtained.

[0243] On the other hand, regarding the sandwich panel structures of Comparative Examples 1~2, since the conditions that the difference in visible light transmittance when the dimming component is driven and when it is not driven is more than 20% and the total sunlight transmittance (Tts) of the dimming component is less than 70% in either the driving or non-driving state are not met, the light-shielding effect and satisfactory contrast difference cannot be obtained.

[0244] Explanation of symbols

[0245] 1 Intermediate film structure for panels (intermediate film structure)

[0246] 10, 10A, 10B dimming components

[0247] 11 Dimming Layer

[0248] 12. First base film

[0249] 13. Second base film

[0250] 20 First thermoplastic resin layer

[0251] 21 Second thermoplastic resin layer

[0252] 22 Third thermoplastic resin layer

[0253] 30, 31 Transparent Panel

[0254] 100 Sandwich panel structure

[0255] 110 Motor Vehicles

[0256] 111 The top of the car.

Claims

1. An intermediate film structure for a sandwich panel, which is an intermediate film structure for a sandwich panel used between two transparent panels. The device comprises a thermoplastic resin sheet and a light-adjusting member sandwiched within the thermoplastic resin sheet. In a laminated glass produced by bonding two transparent glass plates via an intermediate film structure for laminated glass, the difference in visible light transmittance between when the dimming component is driven and when it is not driven is 20% or more, and the total sunlight transmittance, i.e., Tts, is 70% or less in either the driving or non-driving state of the dimming component. 2 . The interlayer film structure for a sandwich panel according to claim 1 , wherein the thermoplastic resin sheet comprises a heat insulating material.

3. The interlayer film structure for a sandwich panel according to claim 1, wherein the thermoplastic resin sheet comprises a first thermoplastic resin layer and a second thermoplastic resin layer. The light control member is disposed between the first thermoplastic resin layer and the second thermoplastic resin layer. 4 . The interlayer film structure for a sandwich panel according to claim 3 , wherein at least one of the first thermoplastic resin layer and the second thermoplastic resin layer comprises a heat insulating material. 5 . The interlayer film structure for a sandwich panel according to claim 1 , wherein the light control member is an electrically controlled light control member.

6. A sandwich panel structure having 2 transparent panels, and The interlayer film for the sandwich panel is arranged between the two transparent panels. The interlayer film for a sandwich panel includes a thermoplastic resin sheet and a light control member sandwiched and arranged inside the thermoplastic resin sheet. The difference in visible light transmittance between the light control member when driven and when not driven is 20% or more, and the light control member has a total sunlight transmittance (Tts) of 70% or less in both the driven and non-driven states.

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