JP7205558B2 - Anti-glare/heat-shielding sheet and anti-glare/heat-shielding laminated glass - Google Patents

Description

TECHNICAL FIELD The present invention relates to an antiglare/heat shielding sheet and an antiglare/heat shielding laminated glass.

Anti-glare means for preventing glare from sunlight, headlights, and LED street lights at night while driving a car include sunglasses, sun visors, and sunshades installed on windshields. In these anti-glare means, if the visible light transmittance is reduced in order to enhance the anti-glare effect, there is a possibility that the colors of traffic signs and signals become difficult to see.

Therefore, attempts have been made to control the light transmittance according to the individual wavelengths of sunlight and the like, thereby maintaining the amount of visible light transmitted to some extent and suppressing only light in a specific wavelength range related to glare. ing.

As a method of suppressing only the light transmittance in a specific wavelength range related to glare, there is a method of using a dye that selectively absorbs light in a specific wavelength range. For example, Patent Document 1 discloses an interlayer film for laminated glass containing trivalent neodymium ions that absorb light with a wavelength of about 580 nm.

Dark adaptation is the gradual adaptation of the eyes when moving from a bright place to a dark place, and light adaptation is the gradual adaptation of the eyes when moving from a dark place to a bright place. call. Rhodopsin, a visual substance contained in rod cells in the retina of the eye, is degraded in bright light and resynthesized in dark. Therefore, dark adaptation requires time to resynthesize rhodopsin, so it takes longer than light adaptation.

If the dark-adapted eyes of a driver who is driving a car at night become light-adapted due to the light from the headlights of an oncoming vehicle, dark-adaptation takes time, visibility decreases, and safety is compromised. end up Therefore, it is considered better to reduce the visible light transmittance during night driving. However, if the visible light transmittance is uniformly reduced, there is a problem that the visibility in a bright place is deteriorated.

Further, in the case of imparting heat shielding properties, materials that absorb heat rays (green glass, ITO fine particles, etc.) have conventionally been used, but the heat shielding performance was not sufficient.

JP-A-2007-55839

The present invention provides an anti-glare/heat-shielding sheet laminated on a glass window, which effectively suppresses glare when strong light suddenly shines in a dark place while maintaining normal visibility. It is also an object of the present invention to provide an antiglare/heat-shielding sheet having excellent heat-shielding properties.

The present inventors have investigated a film that can reduce the transmittance in the dark. As a result, the inventors have found that the wavelength at which the reflectance is maximum can be shifted to the short wavelength side by utilizing multi-layered light interference by a sheet in which a large number of layers having different refractive indices are laminated.

The human eye has different sensitivity to light (visual sensitivity) for each wavelength, and is generally sensitive to light with a wavelength centered at 550 nm in a bright place. is shifted to the short wavelength side. Therefore, if the intensity of light with a wavelength of high visibility can be selectively reduced in a dark place, it is considered that the glare felt from the light in a dark place can be suppressed more effectively. That is, by using multi-layered light interference, the maximum wavelength of reflectance is shifted to the short wavelength side, thereby reducing the visible light transmittance in a dark place while maintaining the visible light transmittance in a bright place. becomes possible. Furthermore, the inventors have found that the heat shielding property is improved by reflecting short wavelengths.

The present invention has been completed based on such studies. That is, the present invention has the following configurations.

(1) An anti-glare/heat-shielding sheet in which two or more dielectric layers with different refractive indices and a heat-shielding layer containing heat-shielding particles and a transparent resin are laminated, and has a wavelength range of 300 to 500 nm. An antiglare/heat shielding sheet having a maximum reflectance, wherein the maximum spectral reflectance is 45% or more.
(2) The antiglare/shielding property according to (1), wherein the heat shielding particles are at least one selected from potassium tungsten oxide, rubidium tungsten oxide, cesium tungsten oxide, thallium tungsten oxide, ITO, and ATO. thermal sheet.
(3) The antiglare/heat shielding sheet according to (1) or (2), wherein the content of the heat shielding particles in the heat shielding layer is 5% by mass or more and 50% by mass or less.
(4) The antiglare/heat shielding sheet according to any one of (1) to (3), wherein the transparent resin is an ultraviolet curable resin, and further contains an oxime compound.
(5) The antiglare/heat shielding sheet according to any one of (1) to (4), which has a visible light transmittance of 70% or more in bright light.
(6) An anti-glare/heat-shielding laminated glass obtained by laminating the anti-glare/heat-shielding sheet according to any one of (1) to (5) between two sheets of glass.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an antiglare/heat shielding sheet which is excellent in antiglare properties and heat shielding properties in a dark place and which is excellent in adhesiveness. In addition, it is possible to provide an antiglare/heat shielding laminated glass which is excellent in antiglare properties and heat shielding properties in a dark place. Furthermore, when used as an anti-glare/heat-shielding laminated glass for automobiles, it moderately reflects the light from the headlights of an oncoming vehicle, so that the visibility is excellent for an observer on the light source side.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing a method for manufacturing the antiglare/heat shielding laminated glass for automobiles of the present embodiment. 1 is a scanning electron microscope (SEM) photograph of a cross section of Film 1. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. However, embodiments of the present invention are not limited to the following embodiments.

The antiglare/heat shielding sheet of this embodiment is formed by laminating two or more dielectric layers having different refractive indices and a heat shielding layer containing heat shielding particles and a transparent resin.

As two or more dielectric layers having different refractive indexes, thermoplastic resins having different refractive indexes (thermoplastic resin A and thermoplastic resin B) are alternately laminated.

The thermoplastic resin used for the dielectric layer is preferably polyester, and polyester obtained by using an aromatic dicarboxylic acid or an aliphatic dicarboxylic acid and a diol or a derivative thereof is particularly preferable. Examples of aromatic dicarboxylic acids include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4'-diphenyl dicarboxylic acid, 4,4'-diphenyletherdicarboxylic acid, 4,4'-diphenylsulfonedicarboxylic acid and the like. Examples of aliphatic dicarboxylic acids include adipic acid, suberic acid, sebacic acid, dimer acid, dodecanedioic acid, cyclohexanedicarboxylic acid and their ester derivatives. Among them, terephthalic acid and 2,6-naphthalenedicarboxylic acid are preferred. These components may be used alone or in combination of two or more, and may be partially copolymerized with an oxyacid such as hydroxybenzoic acid.

Examples of diol components include ethylene glycol, 1,2-propanediol, 1,3-propanediol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1 ,6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2-bis(4-hydroxyethoxy phenyl)propane, isosorbate, spiroglycol, and the like. Among them, ethylene glycol is preferred. You may use these diol components individually by 1 type or in combination of 2 or more types.

Among the above polyesters, polyethylene terephthalate and its copolymer, polyethylene naphthalate and its copolymer, polybutylene terephthalate and its copolymer, polybutylene naphthalate and its copolymer, polyhexamethylene terephthalate and its copolymer , and polyhexamethylene naphthalate and its copolymers, particularly as the thermoplastic resin A.

As the thermoplastic resin B, it is preferable to use the following resin C, D or E as a main component. The thermoplastic resin B of the film of the present invention preferably comprises a mixture of a thermoplastic resin containing resin C, D or E below as a main component and polyethylene terephthalate.
Resin C: Copolymerized polyethylene terephthalate resin obtained by copolymerizing spiroglycol component D: Copolymerized polyethyleneterephthalate resin obtained by copolymerizing spiroglycol component and cyclohexanedicarboxylic acid component E: Copolymerized polyethyleneterephthalate resin obtained by copolymerizing cyclohexanedimethanol component

The heat-shielding particles used in the heat-shielding layer are preferably at least one selected from potassium tungsten oxide, rubidium tungsten oxide, cesium tungsten oxide, thallium tungsten oxide, ITO, and ATO.

The heat-shielding particles are particularly preferably at least one selected from cesium tungsten oxide, which has high visible light transmittance and excellent heat-shielding performance.

The content of the heat-shielding particles in the heat-shielding layer is preferably 5% or more and 50% or less, more preferably 10% or more and 40% or less. By setting the content of the heat-insulating particles in the heat-insulating layer to 5% or more, the thickness of the heat-insulating layer can be reduced. By setting the content of the heat-shielding particles in the heat-shielding layer to 50%, the film strength can be maintained.
Moreover, it is preferable that the content of the heat-shielding particles in the heat-shielding layer is 0.1 g/m ² or more and 2.0 g/m ² or less.

The transparent resin in the heat shield layer can be an ultraviolet curable resin, and the transparent resin can further contain a photopolymerization initiator. By forming the transparent resin in the heat shield layer from a cured product of an ultraviolet curable acrylic monomer/oligomer and a photopolymerization initiator, a heat shield layer in which the heat shield particles are uniformly dispersed can be formed.
As the photopolymerization initiator, an oxime compound that generates radicals even in a long wavelength region around 400 nm is preferable. Since the system containing the particles has absorption in the short wavelength region, it is difficult for radicals to be generated, and poor curing of the acrylic resin tends to occur.

In the antiglare/heat shielding sheet of the present embodiment, the antiglare/heat shielding sheet has a maximum spectral reflectance in the wavelength range of 300 to 500 nm, and the maximum spectral reflectance is 45%. It is the above and is characterized by having a heat shielding performance Tts of less than 55.

The maximum wavelength of the spectral reflectance is desirably in the range of high visibility in the dark, preferably 300 to 500 nm, more preferably 350 to 450 nm.
The maximum value of the spectral reflectance is 45% or more, more preferably 50% or more.
Further, it is preferable that the wavelength-spectral reflectance correlation graph has a maximum spectral reflectance peak at a wavelength of 300 to 500 nm.

The heat shielding performance Tts is less than 55, preferably 54% or less. The heat shielding performance Tts is measured according to ISO13837:2008. Specifically, it is calculated from the formula Tts=27.6+0.724×(solar transmittance)−0.276×(solar reflectance). The transmission and reflection spectra are measured using a spectrophotometer.

The present invention provides an anti-glare/heat-shielding sheet in which two or more dielectric layers having different refractive indices and a heat-shielding layer containing heat-shielding particles and a transparent resin are laminated, and has a wavelength range of 300 to 500 nm. The dielectric layer and the heat-shielding layer have the maximum spectral reflectance, and the prescription of the dielectric layer and the heat-shielding layer are selected and combined so that the maximum spectral reflectance is 45% or more. It has been found that both heat insulation performance and heat shielding performance can be achieved.

Anti-glare properties in dark places are better when the visible light transmittance in bright places is greater than the visible light transmittance in dark places. %) is preferably 0.1% or more, more preferably 3% or more, and still more preferably 10% or more. Visible light transmittance can be measured using an infrared reflectometer in accordance with JIS R3106:1998. In addition, the visible light transmittance in a dark place can be obtained using a weight factor in a dark place (JIS Z 8785 (2019)).

When the antiglare/heat shielding sheet of the present invention is used for automobile window glass, the visible light transmittance in a bright place is preferably 70% or more, preferably 72% or more, in order to ensure visibility. is more preferable. When the antiglare/heat shielding sheet of the present invention is used for automobile window glass, the visible light transmittance (%) in a dark place is preferably 50 to 78%, more preferably 55 to 75%. .

In the dielectric layers used in the antiglare/heat shielding sheet of the present invention, the number of alternately laminated dielectric layers is preferably 4 to 50, more preferably 6 to 30. Also, the thickness of each layer is, for example, 5 to 1000 nm, preferably 10 to 900 nm. The thickness of the entire laminated sheet is, for example, 40 nm to 100 μm, preferably 120 nm to 60 μm. The refractive index difference is preferably 0.02 or more, more preferably 0.4 or more. If the difference in refractive index is large, the effect of the present invention can be obtained even if the number of layers to be laminated is small. Conversely, if the difference in refractive index is small, the number of layers to be laminated must be increased.

The antiglare/heat shielding sheet of the present invention can be laminated on the surface of glass to form an antiglare/heat shielding glass laminate.
Also, the antiglare/heat shielding sheet of the present invention can be laminated between two sheets of glass to form an antiglare/heat shielding laminated glass.

The antiglare/heat shielding laminated glass has an antiglare/heat shielding sheet and two transparent plates sandwiching the antiglare/heat shielding sheet. An antiglare/heat shield laminated glass is formed by providing an adhesive layer on both sides of the antiglare/heat shield sheet and sandwiching it between two transparent plates.
Transparent glass or the transparent resin described above can be used as the transparent plate used for the antiglare/heat shielding laminated glass.

As the glass, soda-lime glass is typical. In order to improve heat ray shielding performance, a glass plate containing iron ions (green glass) can be used as the glass plate that reduces the transmittance in the near-infrared wavelength region (800 to 2500 nm). The glass plate containing iron ions is soda-lime glass containing silicon dioxide (SiO ₂ ), sodium oxide (Na ₂ O), and calcium oxide (CaO) as main components, and the iron content is 0 as Fe ₂ O ₃ . A glass plate containing 3 to 0.9% by mass of iron and having the iron content reduced at a high reduction rate is preferred.

A standard for a high reduction rate of iron is Fe ²⁺ /Fe ³⁺ of 50 to 250%. By reducing the iron content to increase the content of divalent iron ions, the absorbance in the infrared region can be increased. As a method for reducing the iron content, powders such as silica sand, feldspar, soda ash and red iron oxide as soda-lime glass raw materials and carbon as a reducing agent are melted in an electric melting kiln or the like. Also, the reduction rate of iron can be measured by a redox measuring device. The thickness of one glass plate is not particularly limited, but is, for example, about 0.1 to 10 mm, preferably about 1 to 5 mm.

The adhesive layer of the antiglare/heat shielding laminated glass is not particularly limited as long as it is a resin film used as an adhesive layer between the intermediate film of the laminated glass and the transparent plate. Examples of adhesives used in the adhesive layer include polyvinyl acetal resins such as polyvinyl butyral resins (PVB resins), ethylene-vinyl acetate copolymer resins (EVA resins), acrylic resins, silicone resins, and the like. is mentioned. The thickness of the adhesive layer is preferably 100-1000 μm.

Adhesives used in the adhesive layer are appropriately added with UV absorbers, antioxidants, antistatic agents, heat stabilizers, lubricants, fillers, coloring agents, adhesion modifiers, heat absorbing/reflecting agents, etc. may

As a method for producing the antiglare/heat shielding laminated glass, a known method for producing laminated glass can be used. A specific example is described below. FIG. 1 is a schematic diagram showing the method for manufacturing the antiglare/heat shielding laminated glass of this embodiment.

First, as shown in FIG. 1(a), between two glass plates 5, an antiglare/heat shielding film 4 having adhesive layers formed on both sides is laminated. The laminated glass plate 5, antiglare/heat shielding film 4 and glass plate 5 are moved on rollers 21 to proceed to the next step.

Next, as shown in FIG. 1(b), in a sealed chamber 22, the laminated glass plate 5, the antiglare/heat shielding film 4 and the glass plate 5 are heated to 80 to 140° C. by a heater 23. It is heated to a temperature range, for example about 90°C. Subsequently, the laminated glass plate 6, the antiglare/heat shielding film 4 and the glass plate 7 are temporarily pressure-bonded by passing through a pair of pressure bonding rolls 24 .

Next, as shown in FIG. 1(c), the anti-glare/heat-shielding laminated glass 10 temporarily pressure-bonded is placed in an autoclave 25. Next, as shown in FIG. In the autoclave 25, pressure is applied to about 1 MPa, and the temperature range is 80 to 140° C., for example, heating to about 130° C. to remove air bubbles remaining after the temporary pressure bonding, and the antiglare/heat shielding film 4 is formed. The adhesive layer is sufficiently bonded to the glass plate 5 to produce the antiglare/heat shielding laminated glass 10 .

Heating in the step of forming the antiglare/heat shielding laminated glass is carried out twice: heating before temporary pressure bonding and heating in the autoclave 25 . In any case, the heating temperature is preferably 80 to 140°C. Also, usually, the heating temperature is set higher during heating in an autoclave than during heating before temporary pressure bonding.

Since the anti-glare/heat-shielding sheet of the present embodiment is excellent in anti-glare and heat-shielding properties in dark places, it can be applied to windows (especially windshields) of traffic vehicles such as automobiles. can be used. In addition, the antiglare/heat shielding laminated glass can be used as it is as a windshield for automobiles.

The present embodiment will be described more specifically by the following examples.

(Comparative example 1)
(Preparation of antiglare/heat shielding film a)
Using a vacuum evaporator, film formation start vacuum degree: 0.9 mPa, electron beam evaporation, substrate temperature during film formation: 60 ± 30 ° C. ZrO ₂ layer on one side of uniaxially stretched polyethylene terephthalate film (42 μm). A multilayer film having a total thickness of 537 nm was formed by forming a total of 10 layers of SiO ₂ layers by 5 layers alternately to prepare a film a.

(Comparative example 2)
(Anti-glare/heat-shielding film b)
Picassus "40QPA6" (thickness: 42 µm, manufactured by Toray Industries, Inc.) was prepared as the antiglare/heat shielding film b.

( Reference example 1)
(Preparation of antiglare/heat shielding film c)
Paint A having the formulation shown in Table 1 was applied to the multi-layered surface of the antiglare/heat shielding film a with a Meyer bar so that the thickness after drying was 1 μm, and dried at 80° C. for 1 minute. . Next, ultraviolet rays were irradiated from a high-pressure mercury lamp (illuminance of 400 mW/cm ² ) so that the amount of light was 125 mJ/cm ² , and cured to produce a heat shielding film c.

(Example 2)
(Preparation of antiglare/heat shielding film d)
On one side of the antiglare/heat shielding film b, paint A having the formulation shown in Table 1 was applied with a Meyer bar to a thickness of 3 μm after drying, and dried at 80° C. for 1 minute. Next, the film was cured by irradiating ultraviolet rays from a high-pressure mercury lamp (illuminance of 400 mW/cm ² ) so that the amount of light was 125 mJ/cm ² , to produce antiglare/heat shielding film d.

(Example 3)
(Preparation of anti-glare/heat-shielding film e with adhesive layer)
On one side of the antiglare/heat shielding film b, paint A having the formulation shown in Table 1 was applied with a Meyer bar so that the thickness after drying was 1 μm, and dried at 80° C. for 1 minute. Next, a high-pressure mercury lamp (illuminance of 400 mW/cm ² ) is used to irradiate ultraviolet rays so that the amount of light becomes 125 mJ/cm ² , and the film is cured to form a heat-shielding layer to produce an anti-glare/heat-shielding film e. bottom.
A silicone-treated separator sheet (Mitsubishi Plastics, Inc., MRQ#38, 38 μm thick) was coated with paint B having the formulation shown in Table 2 on the silicone-treated surface and dried in a hot air oven at 100° C. for 2 minutes. to form an adhesive layer having a thickness of about 22 μm.
The heat shielding layer surface of the antiglare/heat shielding film e and the adhesive layer surface of the separator sheet were laminated and aged for 7 days to prepare the antiglare/heat shielding film e with adhesive layer.

(Comparative Example 3)
(Preparation of antiglare/heat shielding film f)
On one side of the antiglare/heat shielding film b , the paint C having the formulation shown in Table 3 was applied with a Meyer bar to a thickness of 1 μm after drying, and dried at 80° C. for 1 minute. Next, the film was cured by irradiating ultraviolet rays from a high-pressure mercury lamp (illuminance of 400 mW/cm ² ) so that the amount of light was 125 mJ/cm ² , to produce an antiglare/heat shielding film f.

(Production of laminated glass)
A sheet of PVB (polyvinyl butyral film, manufactured by Sekisui Chemical Co., Ltd., S-LEC PVB 0.38 mm) having a thickness of 380 μm was placed on a float glass plate (thickness 2 mm) as an adhesive layer (hereinafter referred to as “PVB sheet”). ) was placed. On top of this, the antiglare/heat shielding films a to d and f are placed with the laminated portion facing downward, a PVB sheet is placed as an adhesive layer, and finally a glass plate is placed to form an antiglare and heat shielding film. was sandwiched between adhesive layers to obtain a laminate.
As the float glass plate, green glass was used for the antiglare/heat shielding films a to c, and clear glass was used for the antiglare/heat shielding films d and f.
(Comparative Example 4)
A laminate was obtained by sandwiching a PVB sheet with a thickness of 380 μm between two float glass plates (thickness: 2 mm).

The resulting laminate was passed through the production line shown in FIG.
That is, the obtained laminate was heated to about 90° C. in a sealed chamber 22 using a heater 23 . After that, the laminated glass plate 5 and the antiglare/heat shielding film 4 were temporarily pressure-bonded by passing through a pair of pressure bonding rolls 24 . Next, the anti-glare/heat-insulating laminated glass 10 temporarily pressure-bonded was placed in the autoclave 25 . By pressurizing to about 1 MPa and heating at about 130° C. for 30 minutes in an autoclave 25, air bubbles remaining after temporary pressure bonding are removed, and the antiglare/heat shielding film 1 is sufficiently attached to the glass plate 5 by the adhesive layer. An antiglare/heat shielding laminated glass 10 was produced.
A laminate G was obtained as described above.

(Comparative Example 5)
A 380 μm thick PVB (polyvinyl butyral film, S-LEC PVB 0.38 mm, manufactured by Sekisui Chemical Co., Ltd.) sheet (hereinafter referred to as “PVB sheet”) was placed on a green glass plate (2 mm thick) as an adhesive layer. ) was placed. On top of this, the antiglare/heat shielding film a is placed with the laminated part facing downward, a PVB sheet is placed as an adhesive layer, and finally a glass plate is placed, and the antiglare and heat shielding film a is placed on the adhesive layer. A laminate sandwiched between was obtained. The resulting laminate was passed through the production line shown in FIG. 1 to obtain a laminate A.

(Comparative Example 6)
A laminate B was obtained in the same manner as in Comparative Example 5, except that the antiglare and heat shielding film b was used instead of the antiglare and heat shielding film a.

( Reference example 4)
A laminate C was obtained in the same manner as in Comparative Example 5 except that the antiglare and heat shielding film c was used instead of the antiglare and heat shielding film a.

(Example 5)
A laminate was prepared in the same manner as in Comparative Example 5 except that the antiglare and heat shielding film d was used instead of the antiglare and heat shielding film a, and the clear glass (2 mm thickness) was used instead of the green glass plate (2 mm thickness). got a D.

(Example 6)
The adhesive layer-attached antiglare/heat shield film e from which the separator sheet was peeled off was brought into contact with one side of the laminated glass obtained in Comparative Example 4 and the adhesive layer of the adhesive layer-attached antiglare/heat shield film e. By lamination, a laminate E composed of the antiglare and heat shielding film and the laminated glass was obtained.

(Comparative Example 7)
A laminate F was obtained in the same manner as in Example 6, except that the antiglare and heat shielding film f was used instead of the antiglare and heat shielding film d.

<Evaluation items>
(maximum reflection wavelength and reflectance at maximum reflection wavelength)
Using a spectrophotometer (U-4100, manufactured by Hitachi, Ltd.), the spectra of the test pieces of the antiglare / heat shielding films a to f are measured in the wavelength range of 300 to 2500 nm, and the maximum reflection wavelength and the maximum reflection wavelength Table 4 shows the reflectance.
Laminates A to F were similarly measured, and Table 5 shows the maximum reflection wavelength and the reflectance at the maximum reflection wavelength.

(visible light transmittance)
The visible light transmittance of the test pieces of the antiglare/heat shielding films a to f was measured using a D65 light source based on JIS R3106:1998, and the results are shown in Table 4.
Visible light transmittance was similarly measured for laminates A to F, and the results are shown in Table 5.
(Anti-glare property, anti-glare effect)
For the test pieces of the antiglare / heat shielding films a to f, the visible light transmittance in the dark using the D65 light source is calculated using the weight coefficient in the dark described in JIS Z 8785 (2019), Table 4 shows the value of (visible light transmittance in dark place) - (visible light transmittance in bright place).
Similarly, Table 5 shows the values of (visible light transmittance in dark place) - (visible light transmittance in bright place) for laminates A to F.
Bright place visible light transmittance and dark place visible light transmittance are calculated by the following methods.
For the visible light transmittance in bright light, the visible light transmittance formula (1) described in JIS R3106:1998 (5. Calculation of visible light transmittance and visible light reflectance) was used. In addition, the visible light transmittance in the dark is described in JIS Z8785: 2019 (Table 2) as the weighting factor D ^λ · V ^λ in the above formula (1) - Spectral luminous efficiency V' in scotopic vision It was obtained by substituting the value of (λ).

If the value of (dark place visible light transmittance) - (light place visible light transmittance) is in the range of 0 to -9.0%, it can be said that the antiglare property is good.

(Anti-glare effect)
A D65 light source (SOLAX-iO, model: LE-9ND65) manufactured by Seric Co., Ltd. was placed 2 m away from the subject. A test piece of one of the antiglare/heat-shielding films a to f or the laminates A to F was placed at the midpoint between the light source and the test subject so that the light from the light source could pass therethrough. Table 4 shows the results of sensory evaluation of glare when the subject looked at the light source through the test piece according to the following criteria.
Antiglare effect "A": Excellent antiglare effect without feeling glare.
Anti-glare effect "B": Some glare is felt, but there is an anti-glare effect.
Anti-glare effect "C": Felt glare, little anti-glare effect.

(Heat barrier properties)
(solar transmittance and solar reflectance)
The solar transmittance and solar reflectance of the test pieces of the antiglare/heat shielding films a to f were measured according to JIS R3106:1998, and the results are shown in Table 4.
The solar transmittance and solar reflectance of the laminates A to F were similarly measured, and the results are shown in Table 5.
The total solar transmittance (Tts) was calculated according to the following formula defined in ISO13837:2008, and the values are shown in Table 4.
Tts = 27.6 + 0.724 x (solar transmittance) - 0.276 x (solar reflectance)
If Tts is less than 56.0%, it can be said to have good heat shielding performance.

(Adhesion)
The antiglare/heat shielding films c to f were evaluated for adhesion based on JIS A5400 (1999), and the results are shown in Table 4. A cutter was used to cut the surface of the thermal barrier layer into 100 squares of 1 mm each. When even one piece was peeled off, it was judged as ×, and when none of them were peeled off, it was judged as ◯. If the adhesion evaluation is ◯, it can be considered to be excellent for automobile windshields.

FIG. 2 is a scanning electron microscope (SEM) photograph of a cross section of film 1. FIG.

As shown in Examples 1 to 3, the films c, d, and f, which are the antiglare/heat shielding sheets of the present invention, have both high antiglare properties and heat shielding properties, and have excellent adhesion to the dielectric layer. It was an antiglare and heat shielding sheet. In addition, since it exhibits an appropriate reflectance in the wavelength range of 300 to 500 nm, it has excellent visibility for an observer from the light source side, such as an oncoming vehicle.
Further, as shown in Examples 4 to 6, the laminates C, D, and F, which are the antiglare/heat shielding laminated glass of the present invention, have both high antiglare properties and heat shielding properties, and further adhere to the dielectric layer. It was an anti-glare/heat-shielding laminated glass with excellent properties. In addition, since it exhibits an appropriate reflectance in the wavelength range of 300 to 500 nm, it has excellent visibility for an observer from the light source side, such as an oncoming vehicle.

Claims (6)

An anti-glare/heat-shielding sheet in which a layer in which thermoplastic resins (thermoplastic resin A and thermoplastic resin B) with different refractive indices are alternately laminated and a heat-shielding layer containing heat-shielding particles and a transparent resin are laminated. An antiglare/heat shielding sheet, characterized by having a maximum spectral reflectance in a wavelength range of 350 to 450 nm, wherein the maximum spectral reflectance is 45% or more.
2. The antiglare/heat shielding sheet according to claim 1, wherein said heat shielding particles are at least one selected from potassium tungsten oxide, rubidium tungsten oxide, cesium tungsten oxide, thallium tungsten oxide, ITO and ATO. 3. The antiglare/heat shielding sheet according to claim 1, wherein the content of the heat shielding particles in the heat shielding layer is 5% by mass or more and 50% by mass or less. The antiglare/heat shielding sheet according to any one of claims 1 to 3, wherein the transparent resin is an ultraviolet curable resin, and the transparent resin further contains an oxime compound. The antiglare/heat shielding sheet according to any one of claims 1 to 4, which has a visible light transmittance of 75% or more in bright light. An anti-glare/heat-shielding laminated glass obtained by laminating the anti-glare/heat-shielding sheet according to any one of claims 1 to 5 between two sheets of glass.

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