JP2023110548A - Optical laminate and mirror member - Google Patents

Abstract

To provide an optical laminate with visible light reflecting and heat insulating properties, and a mirror member.SOLUTION: An optical laminate is provided, comprising a metal reflection layer, an optical adjustment layer, and a function layer arranged in the described order on a base material, where the optical adjustment layer comprises at least one high refractive index layer having a refractive index of 1.75 or greater, and the optical laminate has a solar reflectance of 82% or less. A mirror member with such an optical laminate is also provided.SELECTED DRAWING: Figure 2

Description

The present invention relates to an optical layered body and a mirror member using the same.

A driver of a vehicle gazes ahead through the windshield and drives the vehicle while visually observing the gauges on the instrument panel. That is, the line of sight moves forward and downward to the instruments. If you can see the instruments while looking ahead, you can expect to improve drivability (and ultimately safety) without moving your line of sight. Based on this knowledge, a head-up display (HUD) device has been developed and put into practical use.

In the head-up display device, an image from the light source is formed as a virtual image on the windshield in the dashboard device, so that the image is visually recognized by the driver. In order to project the image information from the light source without lowering the luminance, a specular body with a high visible light reflectance is required.
From the viewpoint of improving driving safety, head-up displays, which require less movement of the viewpoint, are attracting more and more attention day by day, and the demand for mirror-surface bodies used as reflecting mirrors for such displays is also increasing. In addition, plastic substrates, especially polycarbonate substrates, etc., are used because of their high heat resistance, as the support substrates that make up the mirror-like bodies, because they have a low risk of being damaged in an accident such as a vehicle collision and are light in weight. there is

In the conventional method for producing a mirror-like body, it was common to form a metal thin film on a support substrate such as a polycarbonate substrate using a batch-type vapor deposition/sputtering device. However, the production efficiency of the batch production method is low, and the demand for mirror bodies tends to increase day by day. Further, the specular body is required to have a high reflectance and suppress distortion of reflected light.

Film mirrors that can be attached to a support are also being studied. For example, Patent Document 1 discloses a film mirror having at least a light reflecting layer, a resin base material, and an adhesive layer, wherein the adhesive layer is formed of an acrylic adhesive, and is used in a solar power generation reflector. ing.

On the other hand, an optical layered body that reflects light and can be attached to a support has been studied. For example, in Patent Document 2, an aluminum surface reflector in which a first low refractive index layer, a high refractive index layer and a second low refractive index layer are laminated in this order on an aluminum surface, and this is installed on a substrate Standards for reflectometry are disclosed.

JP 2015-210335 A JP-A-5-173005

In recent years, as the projected image projected by the HUD device has become larger, the projection aperture of the HUD device has also become larger. Due to the incidence of sunlight through this opening and the increased brightness of the PGU (Picture Generation Unit, an image generation unit inside the HUD device), the heat damage to the projection source such as the liquid crystal display and the light source inside the HUD device is increasing. is the problem.

Therefore, the inventors studied a mirror body having a heat-shielding property, and aimed to reduce the thermal damage caused by the sunlight incident from the projection opening being reflected by the mirror body and reaching the projection source in the HUD device. investigated. When a conventional film containing an infrared absorber is used on the surface of the mirror surface, although heat shielding properties are obtained, sufficient visible light reflectance cannot be obtained. It was found that the reflection performance was not sufficient.

The present invention has been completed in view of the above, and an object of the present invention is to provide an optical layered body and a mirror member having heat shielding properties while maintaining visible light reflection performance.

As a result of intensive research, the present inventors have found that in a laminate comprising a metal reflective layer, an optical adjustment layer, and a functional layer in this order on a base material, the refractive index of the high refractive index layer included in the optical adjustment layer is is within a specific range, and the solar reflectance of the laminate is set to a predetermined value or higher to solve the above problems.

That is, the present invention is as follows.
[1]
a metal reflective layer, an optical adjustment layer, and a functional layer provided in this order on a substrate;
The optical adjustment layer includes at least one high refractive index layer having a refractive index of 1.75 or more,
An optical laminate having a solar reflectance of 82% or less.
[2]
The optical laminate according to [1], wherein the functional layer contains an infrared absorber.
[3]
The optical laminate according to [2], wherein the functional layer contains 1 to 10% by mass of the infrared absorbing agent.
[4]
The optical laminate according to [2] or [3], wherein the infrared absorber contains cesium-doped tungsten oxide.
[5]
The optical laminate according to any one of [1] to [4], which has a reflectance Y of 85% or more.
[6]
The optical laminate according to any one of [1] to [5], wherein the metal reflective layer contains aluminum or an aluminum alloy.
[7]
The optical laminate according to any one of [1] to [6], which is in the form of a film.
[8]
A mirror member comprising the optical laminate according to any one of [1] to [7].

INDUSTRIAL APPLICABILITY The present invention can provide an optical laminate and a mirror member that have visible light reflection performance and heat shielding properties.

FIG. 1 is a schematic cross-sectional view of an optical layered body according to one embodiment of the present invention. FIG. 2 is a schematic cross-sectional view of an optical laminate according to one embodiment of the invention. FIG. 3 is a schematic cross-sectional view of a mirror member according to one embodiment of the invention.

DETAILED DESCRIPTION OF THE INVENTION Embodiments for carrying out the present invention will be described in detail below. In addition, this invention is not limited to embodiment described below.

[Optical laminate]
FIG. 1 shows a schematic cross-sectional view of an optical laminate 1 according to one embodiment of the present invention.
The optical laminate 1 according to the embodiment of the present invention includes a metal reflective layer 11, an optical adjustment layer 13, and a functional layer 14 in this order on a substrate 10,
The optical adjustment layer 13 includes at least one high refractive index layer having a refractive index of 1.75 or more,
Solar reflectance is 82% or less.

The optical layered body 1 according to the embodiment of the present invention is provided with the optical adjustment layer 13 including at least one high refractive index layer having a refractive index of 1.75 or more to adjust the reflection spectrum, and the reflectance in the visible light region is can be raised.

(solar reflectance)
The optical layered body according to the embodiment of the present invention has a solar reflectance of 82% or less. If the solar reflectance exceeds 82%, the heat shielding property becomes insufficient, and when the optical layered body is applied to the mirror body of the HUD device, the heat load on the projection source cannot be reduced.
The solar reflectance is preferably 80% or less, more preferably 70% or less, from the viewpoint of improving heat shielding properties.

Here, the solar reflectance of the optical layered body according to the embodiment of the present invention is measured by irradiating light with a wavelength of 300 to 2500 nm from the functional layer side.
In the present specification, the solar reflectance is measured using D65 as a standard light source with a Hitachi spectrophotometer U-4100 measuring instrument manufactured by Hitachi High-Tech Science Co., Ltd., and is calculated according to JIS K 5602 "Solar radiation of the coating film. Derived according to "How to determine reflectance". Specifically, it can be measured by the method described in Examples.

(Reflectance Y)
The optical layered body according to the embodiment of the present invention preferably has a reflectance Y of 80% or more from the viewpoint of ensuring reflection performance as a specular body in a head-up display device.
The reflectance Y represents visual sensation, and is more preferably 85% or more, more preferably 90% or more, from the viewpoint of reflection of displayed images.

The reflectance Y of the optical layered body and the mirror member according to the present embodiment is the reflectance in the visible light region, and is the reflectance of the reflected light when visible light in the wavelength range of 380 nm to 780 nm is irradiated from the functional layer side. be.
The reflectance Y can be measured with a spectrophotometer U-4100 manufactured by Hitachi High-Tech Science Co., Ltd. using D65 as a standard light source. Specifically, the reflectance Y can be measured by the method described in Examples.

The reflectance Y can be adjusted by, for example, the laminated structure of the optical adjustment layer 13, the concentration of the infrared absorbing agent contained in the functional layer 14, and the like.

(Infrared absorption rate)
The functional layer in the optical layered body according to the embodiment of the present invention preferably has an infrared absorption rate of 5% or more, more preferably 10% or more, from the viewpoint of lowering the solar reflectance. Moreover, from the viewpoint of reducing the influence on the reflectance Y, it is preferably 30% or less, more preferably 25% or less.
In the optical layered body according to the embodiment of the present invention, the reflectance and transmittance were measured when light with a wavelength of 1000 nm was incident on the surface on the functional layer side, and the values obtained by subtracting the reflectance and transmittance from 100% were obtained. Infrared absorption rate of the functional layer.

The infrared absorptance can be measured with a spectrophotometer U-4100 manufactured by Hitachi High-Tech Science Co., Ltd. Specifically, it can be measured by the method described in Examples.

The infrared absorptance can be adjusted, for example, by setting the type and concentration of the infrared absorbent contained in the functional layer 14 and the film thickness of the functional layer 14 within the preferred ranges described later.

Each layer will be described in detail below.

<Base material>
The material of the base material 10 is not particularly limited, and examples thereof include polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polybutylene terephthalate, polyamide, polyvinyl chloride, polycarbonate (PC), cycloolefin polymer (COP), polystyrene. , polypropylene (PP), polyethylene, polycycloolefin, polyurethane, acrylic (PMMA), ABS, and other homopolymers and copolymers. These members are transparent, have little optical absorption, and do not affect visual effects. However, since various layers will be formed on the base material 10 later, it is preferable that the material can withstand high temperatures such as vapor deposition and sputtering. Polycarbonate, cycloolefin polymer, ABS, polypropylene, polyurethane are preferred. Among them, polyethylene terephthalate, cycloolefin polymer, polycarbonate, and acrylic are preferable because they have a good balance between heat resistance and cost. The substrate 10 may be a single layer or a laminate.

The shape of the substrate 10 is not particularly limited. Examples of the shape of the substrate 10 include a flat plate-like shape, a curved plate-like shape, a sheet-like shape, and a film-like shape.
The thickness of the base material 10 is not particularly limited. When the optical layered body 1 is formed into a film, the thickness of the substrate 10 is preferably 6 μm to 250 μm, for example, from the viewpoint of ease of processing. It is more preferably 20 μm or more, and still more preferably 40 μm or more. Also, it is more preferably 100 μm or less, and still more preferably 75 μm or less. In addition, in order to strengthen the adhesive force with the layer formed on the base material, plasma treatment, corona treatment, and adhesion-enhancing treatment may be applied.

A hard coat layer such as a smooth or antiglare hard coat layer may be formed on the substrate 10 as necessary. By providing the hard coat layer, the scratch resistance can be improved.

The hard coat layer can be formed from a hard coat composition. More specifically, it can be formed by applying a solution containing a curable resin to the substrate 10 as a hard coat composition.
The curable resin contained in the hard coat composition includes thermosetting resins, ultraviolet curable resins, electron beam curable resins, and the like. Types of curable resins include polyester, acrylic, urethane, acrylic urethane, amide, silicone, silicate, epoxy, melamine, oxetane, and acrylic urethane resins. One or more of these curable resins can be appropriately selected and used. Among these resins, acrylic resins, acrylic urethane resins, and epoxy resins are preferable because they have high hardness, can be cured with ultraviolet rays, and are excellent in productivity.

There is no particular limitation on the thickness of the hard coat layer. When the substrate is a film, the thickness of the hard coat layer is preferably 0.5 µm or more, more preferably 1.0 µm or more, and is preferably 10 µm or less, more preferably 7.0 µm or less, and even more preferably. is 5.0 μm or less. The thickness of the hard coat layer can be measured using, for example, a film thickness meter (digital dial gauge).

The thickness of the hard coat layer is preferably 0.5 μm or more, more preferably 1.0 μm or more, and is preferably 10 μm or less, more preferably 7.0 μm or less, and still more preferably 5.0 μm or less. The thickness of the hard coat layer can be measured using, for example, a film thickness meter (digital dial gauge) or an optical interference film thickness meter.

<Metal reflective layer>
The metal reflective layer 11 in this embodiment is formed on the substrate 10 . The metallic reflective layer 11 is preferably a layer having metallic luster. The material forming the metal reflective layer 11 is not particularly limited, and may contain metal and resin. The metal reflective layer 11 may be a metal layer.
A case where the metal reflective layer 11 is a metal layer will be described.

The metal reflective layer 11 is desirably formed of a metal having a relatively low melting point, as well as being capable of exhibiting sufficient luster. This is because the metal reflective layer 11 is preferably formed by thin film growth using sputtering. For this reason, metals having a melting point of about 1000° C. or less are suitable for the metal reflective layer 11, and examples thereof include aluminum (Al), zinc (Zn), lead (Pb), copper (Cu), silver ( It preferably contains at least one metal selected from Ag) and an alloy containing the metal as a main component.
In particular, the metal reflective layer 11 preferably contains aluminum or an aluminum alloy for reasons such as brightness, stability, and price of the material. Moreover, when using an aluminum alloy, it is preferable to make aluminum content into 50 mass % or more.

The thickness of the metal reflective layer 11 is usually preferably 20 nm or more so as to exhibit sufficient brightness, while it is usually preferably 100 nm or less from the viewpoint of productivity. For example, it is preferably 20 nm to 100 nm, more preferably 30 nm to 70 nm. This thickness is also suitable for forming a uniform film with good productivity, and the appearance is also good when a mirror member produced by attaching the optical laminate 1 to a supporting substrate is used as a mirror body. .

<Optical adjustment layer>
The optical laminate 1 according to the embodiment of the present invention has an optical adjustment layer 13 on the surface of the metal reflective layer 11 opposite to the substrate 10 . The optical adjustment layer 13 according to the embodiment of the invention includes at least one high refractive index layer having a refractive index of 1.75 or higher.
By including the high refractive index layer as the optical adjustment layer, it is possible to adjust the reflection spectrum and increase the reflectance in the visible light region.
As used herein, "refractive index" means a value measured in accordance with JIS K0062:1992 using light of wavelength λ=550 nm at a temperature of 25° C., unless otherwise specified.

(High refractive index layer)
The high refractive index layer essential in the optical adjustment layer according to the embodiment of the present invention is a layer having a refractive index of 1.75 or more, preferably 1.75 to 3.2, more preferably 1.80. ~2.40. When a plurality of high refractive index layers are provided, the refractive indexes of the high refractive index layers may be the same or different.

The high refractive index layer is preferably a layer made of metal oxide and/or metal nitride. The metal elements contained in the metal oxides and metal nitrides referred to here include semimetal elements such as Si. Metal oxides and/or metal nitrides also include metal oxynitrides. Moreover, the metal oxide may be an oxide of a single metal element (single oxide) or an oxide of a plurality of metal elements (composite oxide). Similarly, the metal nitride may be a nitride of a single metal element (single nitride) or a nitride of a plurality of metal elements (composite nitride).
Examples of metal elements include Ce, Nb, Si, Sb, Ti, Ta, Zr, and Zn.

Specific examples of materials for the high refractive index layer include CeO ₂ (2.30), NbO (2.33), Nb ₂ O ₃ (2.15), and Nb ₂ O ₅ (2.32). , SiN (2.03), _Sb2O3 ( _2.10 ), _TiO2 (2.35), _Ta2O5 ( _2.10 ), _ZrO2 (2.05), ZnO (2.10) , ZnS (2.30), tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO), and the like (the numerical value in parentheses of each of the above materials is the refractive index).
In particular, the high refractive index layer preferably contains at least one selected _{from Nb} , _Si and _Ti . niobium).

The thickness of the high refractive index layer is preferably 10 nm or more, more preferably 20 nm or more, and even more preferably 30 nm or more from the viewpoint of adjusting the visible light reflection spectrum to a desired range. From the viewpoint of adjusting the visible light reflection spectrum to a desired range, the thickness is preferably 100 nm or less, more preferably 80 nm or less, and even more preferably 70 nm or less.

The optical adjustment layer may be a laminate of layers having different refractive indices, and may include a low refractive index layer in addition to the high refractive index layer.
As shown in FIG. 2, the optical layered body 1 according to the embodiment of the present invention includes, as the optical adjustment layer 13, from the metal reflective layer 11 side, the first low refractive index layer 13a, the high refractive index layer 13b, and It is preferable to have the second low refractive index layer 13c in this order.

(Low refractive index layer)
The low refractive index layer is a layer having a lower refractive index than the high refractive index layer, and its refractive index is, for example, 1.35 to 1.55, preferably 1.40 to 1.50. One or a plurality of low refractive index layers may be provided, and when a plurality of low refractive index layers are provided, the refractive indices of the low refractive index layers may be the same or different. For example, the optical adjustment layer may include two low refractive index layers, a first low refractive index layer and a second low refractive index layer, wherein the refractive index of the first low refractive index layer is It may be the same as or different from the two low refractive index layers.

Examples of materials for the low refractive index layer include metal oxides and metal fluorides.
The metal elements contained in the metal oxides and metal fluorides referred to here include metalloid elements such as Si. Metal oxides and/or metal fluorides also include metal acid fluorides. Moreover, the metal oxide may be an oxide of a single metal element (single oxide) or an oxide of a plurality of metal elements (composite oxide). Similarly, the metal fluoride may be a fluoride of a single metal element (single fluoride) or a fluoride of a plurality of metal elements (composite fluoride).
Examples of metal elements include Si and Mg.

A specific example of the metal oxide is silicon oxide (SiO ₂ : refractive index 1.46). Specific examples of metal fluorides include magnesium fluoride and fluorosilicic acid. The materials of the first low refractive index layer and the second low refractive index layer are preferably magnesium fluoride and fluorosilicic acid from the viewpoint of refractive index, and oxidation from the viewpoint of ease of manufacture, mechanical strength, moisture resistance, etc. Silicon is preferable, and silicon oxide is preferable when various characteristics are comprehensively considered. When a plurality of low refractive index layers are provided, the materials of the low refractive index layers may be the same or different, but all of the low refractive index layers preferably contain silicon oxide.

The thickness of the first low refractive index layer is preferably 50 nm or more, more preferably 66 nm or more, and even more preferably 68 nm or more from the viewpoint of adjusting the visible light reflection spectrum to a desired range. From the viewpoint of adjusting the visible light reflection spectrum to a desired range, the thickness is preferably 100 nm or less, more preferably 78 nm or less, and even more preferably 75 nm or less.

From the viewpoint of adjusting the visible light reflection spectrum to a desired range, the upper limit of the thickness of the second low refractive index layer is preferably 50 nm or less, more preferably 45 nm or less.

Moreover, the laminated structure of the optical adjustment layer 13 is not particularly limited as long as it includes at least one high refractive index layer having a refractive index of 1.75 or more.

The optical layered body 1 includes, as a medium refractive index layer having a refractive index of about 1.50 to 1.85, for example, titanium oxide or a mixture of the above low refractive index material and high refractive index material (a mixture of titanium oxide and silicon oxide). etc.).
The optical adjustment layer has, for example, the above-described three-layer structure of the first low refractive index layer, the high refractive index layer, and the second low refractive index layer from the metal reflective layer 11 side; the high refractive index layer; Four-layer structure of a first low refractive index layer, a high refractive index layer, and a second low refractive index layer; A five-layer structure including a refractive index layer and a second low refractive index layer may be used.
Also, the optical adjustment layer may be a laminate of six or more thin films.

<Function layer>
The optical laminate 1 according to the embodiment of the present invention has a functional layer 14 on the surface of the optical adjustment layer 13 opposite to the metal reflective layer 11 .
In the prior art, a mirror member in which an optical laminate is attached to a supporting base material not only reflects an image from the light source of the head-up display device, but also reflects sunlight to the light source. There was a problem of heat load. The present inventors considered that the fact that the optical layered body reflects sunlight, especially infrared light, causes the problem of the heat load on the light source. As a result of studies by the present inventors, the optical layered body 1 according to the embodiment of the present invention is provided with the functional layer 14, thereby maintaining a high reflectance in the visible light range and reducing the solar reflectance, The present inventors have found that an optical layered body with little reflection of infrared light can be obtained.
The functional layer 14 is a layer provided mainly for the purpose of absorbing light in the near-infrared region. can be reduced.

(Infrared absorber)
The functional layer preferably contains an infrared absorber.
An infrared absorbing agent is a material that selectively absorbs light mainly having wavelengths in the near-infrared region.

Infrared absorbents include inorganic infrared absorbents and organic pigment infrared absorbents.
Examples of inorganic infrared absorbers include metal oxides such as ITO, ATO, LaB6 (lanthanum hexaboride), and CsWO (cesium tungsten oxide).
Organic pigment-based infrared absorbers include compounds such as phenylenediamine dyes, cyanine dyes, phthalocyanine dyes, naphthalocyanine compounds, nickel dithiolene complexes, squalium dyes, quinone compounds, diimmonium compounds, and azo compounds.
From the viewpoint of durability, the infrared absorber is preferably a metal oxide, and more preferably cesium tungsten oxide (cesium-doped tungsten oxide). That is, the infrared absorber preferably contains cesium-doped tungsten oxide.

A commercially available infrared absorbing agent may be used, and as an inorganic infrared absorbing agent, for example, CWO (registered trademark) (manufactured by Sumitomo Metal Mining Co., Ltd., cesium-doped tungsten oxide) can be used. Further, as the organic pigment-based infrared absorbing agent, for example, CIR (manufactured by Nippon Carlit Co., Ltd., phenylenediamine type) or the like can be used.

From the viewpoint of exhibiting the infrared absorbing function, the infrared absorbing agent is preferably contained in the functional layer in an amount of 1% by mass or more, more preferably 2% by mass or more, and even more preferably 3% by mass or more. In addition, although the infrared absorbing agent mainly selectively absorbs light with wavelengths in the near-infrared region, it can also absorb light with wavelengths in the visible light region. is preferably 10% by mass or less, more preferably 7% by mass or less, and even more preferably 5% by mass or less.
That is, the content of the infrared absorbing agent in the functional layer is preferably 1 to 10% by mass, more preferably 2 to 7% by mass.

The functional layer preferably contains a curable resin in addition to the infrared absorber. Examples of the curable resin include thermosetting resin, ultraviolet curable resin, electron beam curable resin, and the like.
Types of curable resins include polyester, acrylic, urethane, acrylic urethane, amide, silicone, silicate, epoxy, melamine, oxetane, and acrylic urethane resins. One or more of these curable resins can be appropriately selected and used. Among these resins, acrylic resins, acrylic urethane resins, and epoxy resins are preferable because they have high hardness, can be cured with ultraviolet rays, and are excellent in productivity.

The functional layer can be formed from the composition for forming a functional layer. More specifically, it can be formed by applying a solution containing an infrared absorber and a curable resin as a composition for forming a functional layer to the optical adjustment layer.

The thickness of the functional layer is preferably 0.5 μm or more, more preferably 1.0 μm or more from the viewpoint of exhibiting the infrared absorption function, and preferably 10 μm or less, more preferably 7.0 μm or less from the viewpoint of flexibility. is. The thickness of the functional layer can be measured using, for example, a film thickness meter (digital dial gauge) or an optical interference film thickness meter.

<Other layers>
The optical layered body 1 according to the embodiment of the present invention may include other layers in addition to the substrate 10, the metal reflective layer 11, the optical adjustment layer 13, and the functional layer 14 depending on the application.
Other layers include, for example, an adhesive layer, a protective layer, a hard coat layer, a barrier layer, an easily adhesive layer, an antireflection layer, a light extraction layer, an antiglare layer, and the like.
For example, some oxides, such as niobium oxide, are reduced when exposed to ultraviolet light while laminated with an adhesive. In order to prevent the reduction action, a layer made of silicon oxide is further laminated as a protective layer. You may have

<Adhesive layer>
The adhesive layer can be formed from an adhesive.
As shown in FIG. 3, the optical layered body 1 according to the embodiment of the present invention can be used as a mirror member 100, for example, by being attached to a support substrate 21 with an adhesive layer 12 interposed therebetween.
The adhesive that forms the adhesive layer 12 is preferably a transparent adhesive, such as an acrylic adhesive, a rubber adhesive, a silicone adhesive, a polyester adhesive, a urethane adhesive, an epoxy adhesive, and polyether-based pressure-sensitive adhesives can be used alone, or two or more of them can be used in combination. From the viewpoint of transparency, workability, durability, etc., it is preferable to use an acrylic pressure-sensitive adhesive.

The pressure-sensitive adhesive layer 12 is preferably protected by a release liner until it is attached to an adherend.

The adhesive that forms the adhesive layer 12 is preferably formed from an adhesive composition containing a base polymer (hereinafter sometimes simply referred to as "adhesive composition"). As the base polymer, it is possible to use a known polymer used for pressure-sensitive adhesives. Here, the base polymer means the main component of the polymer contained in the pressure-sensitive adhesive composition. In this specification, the term "main component" refers to a component contained in an amount exceeding 50% by mass, unless otherwise specified.

(Adhesive composition)
The adhesive composition preferably contains a (meth)acrylic polymer as a base polymer. (Meth)acrylate refers to acrylate and/or methacrylate. A part of the monomers constituting the (meth)acrylic polymer may be contained as unreacted monomers in the pressure-sensitive adhesive composition.

The (meth)acrylic polymer in the embodiment of the present invention is preferably a hydroxyl group-containing (meth)acrylic polymer containing alkyl (meth)acrylate and a hydroxyl group-containing monomer as monomer units. The method of introducing hydroxyl groups is not particularly limited, but for example, a method of copolymerizing hydroxyl group-containing monomers can be easily carried out.

Incidentally, (meth)acrylic polymer in the embodiment of the present invention refers to acrylic polymer and/or methacrylic polymer, (meth)acrylate refers to acrylate and/or methacrylate, and alkyl (meth)acrylate refers to alkyl acrylate and/or alkyl methacrylate.

Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. be done. These compounds may be used alone or in combination of two or more.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl ( meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl acrylate, N-methylol (meth)acrylamide, N-hydroxy (meth)acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether and the like. These monomers may be used alone or in combination of two or more.

The hydroxyl group-containing monomer may be used alone or in combination of two or more. It is preferably 40 parts by mass, more preferably 2 to 30 parts by mass. By copolymerizing a hydroxyl group-containing monomer, a hydroxyl group-containing (meth)acrylic polymer to which reaction points are imparted by cross-linking or the like is obtained.

The (meth)acrylic polymer used in the embodiment of the present invention preferably has a weight average molecular weight of about 300,000 to 2,500,000. When the weight-average molecular weight is less than 300,000, the cohesive force of the pressure-sensitive adhesive composition tends to be low, resulting in adhesive residue. The weight average molecular weight refers to the one obtained by measuring by GPC (gel permeation chromatography).

In addition, the (meth)acrylic polymer preferably has a glass transition temperature (Tg) of 0° C. or lower (usually −100° C. or higher), preferably −10° C. or lower, because it is easy to balance adhesive properties. When the glass transition temperature is higher than 0°C, the polymer becomes difficult to flow. The glass transition temperature (Tg) of the (meth)acrylic polymer can be adjusted within the above range by appropriately changing the monomer components and composition ratio used.

In addition to the above monomers, other polymerizable monomers, such as polymerizable monomers for adjusting the glass transition point and peelability of the (meth)acrylic polymer, are used within a range that does not impair the effects of the present invention. be able to.

Other polymerizable monomers used in (meth)acrylic polymers include, for example, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, cyano group-containing monomers, vinyl ester monomers, aromatic vinyl monomers, etc. Functionality improving components, acid anhydride group-containing monomers, amide group-containing monomers, amino group-containing monomers, epoxy group-containing monomers, N-acryloylmorpholine, vinyl ether monomers, etc. Ingredients can be used as appropriate. These monomer compounds may be used alone or in combination of two or more.

Examples of the cyano group-containing monomer include acrylonitrile and methacrylonitrile.

Examples of the vinyl ester monomer include vinyl acetate, vinyl propionate, and vinyl laurate.

Examples of the aromatic vinyl monomers include styrene, chlorostyrene, chloromethylstyrene and α-methylstyrene.

Examples of the amide group-containing monomer include acrylamide, diethylacrylamide, N-vinyl-2-pyrrolidone and the like.

Examples of the amino group-containing monomers include N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, N-(meth)acryloylmorpholine, and alkylaminoalkyl (meth)acrylates. and esters.

Examples of the epoxy group-containing monomer include glycidyl (meth)acrylate and allyl glycidyl ether.

Examples of the vinyl ether monomer include methyl vinyl ether, ethyl vinyl ether, isobutyl vinyl ether and the like.

In the embodiment of the present invention, the other polymerizable monomers may be used alone or in combination of two or more, but the total content is 100 (meth) acrylic polymer It is preferably from 0 to 40 parts by mass, more preferably from 0 to 30 parts by mass.

The polymerization method of the (meth)acrylic polymer is not particularly limited, and known polymerization methods such as solution polymerization, emulsion polymerization, suspension polymerization and UV polymerization can be employed. Further, the obtained copolymer may be any of random copolymer, block copolymer, graft copolymer and the like.

In an embodiment of the present invention, the pressure-sensitive adhesive composition may contain polymer components other than the base polymer.

In an embodiment of the present invention, the pressure-sensitive adhesive composition preferably contains a cross-linking agent, and an isocyanate-based cross-linking agent is preferably used as the cross-linking agent. An isocyanate-based cross-linking agent is used to impart adhesion and cohesiveness.

Polyfunctional isocyanate compounds are used as isocyanate cross-linking agents, and include various compounds having two or more isocyanate groups in the molecule.

Examples of isocyanate compounds include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate; 2,4-tolylene diisocyanate; Aromatic isocyanates such as 4,4′-diphenylmethane diisocyanate and xylylene diisocyanate, trimethylolpropane/tolylene diisocyanate trimer adduct (trade name: Coronate L, manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane/hexamethylene Isocyanate adducts such as diisocyanate trimer adduct (trade name Coronate HL, manufactured by Nippon Polyurethane Industry Co., Ltd.) and isocyanurate of hexamethylene diisocyanate (trade name Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.). Among them, those having an isocyanurate ring are particularly preferable, for example, polyisocyanate having a long-chain alkylenediol-modified isocyanurate ring (manufactured by Dainippon Ink and Chemicals, Barnock DN-995), isocyanurate of hexamethylene diisocyanate. (trade name: Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.). These compounds may be used alone or in combination.

The content of the cross-linking agent used in the embodiment of the present invention may be blended to the extent that it does not affect the adhesive properties, but usually 0.2 to 10 parts by mass with respect to 100 parts by mass of the (meth)acrylic polymer. It is preferably contained in an amount of 0.5 to 8 parts by mass, more preferably 1 to 6 parts by mass.

In an embodiment of the present invention, the pressure-sensitive adhesive composition also preferably contains a polyfunctional (meth)acrylic monomer such as 1,6-hexanedioldiacrylate as a cross-linking component. In addition, the (meth)acrylic monomer in the embodiment of the present invention refers to an acrylic monomer and/or a methacrylic monomer.
The polyfunctional (meth) acrylic monomer is usually contained in an amount of 0.2 to 10 parts by weight, preferably 0.5 to 8 parts by weight, based on 100 parts by weight of the (meth) acrylic polymer. It is more preferable to contain 6 parts by mass.

The acrylic pressure-sensitive adhesive may include cross-linking agents (polyamine compounds, melamine resins, aziridine derivatives, urea resins) other than those exemplified above, polymerization initiators, tackifiers, plasticizers, silane coupling agents, colorants, and pigments. Powders such as dyes, surfactants, surface lubricants, leveling agents, softeners, antioxidants, antistatic agents, antiaging agents, light stabilizers, UV absorbers, polymerization inhibitors, inorganic or organic fillings Agents, metal powders, particles, foils and the like can also be used as appropriate. These components may be used alone or in combination of two or more.

(Method for Forming Adhesive Layer)
The pressure-sensitive adhesive layer can also be formed, for example, by coating the pressure-sensitive adhesive composition on a substrate and removing the solvent and the like by drying. In applying the pressure-sensitive adhesive composition, one or more solvents may be added as appropriate.
Alternatively, the pressure-sensitive adhesive layer may be formed, for example, by laminating the pressure-sensitive adhesive layer side surface of the laminate of the pressure-sensitive adhesive layer formed on the release liner with the pressure-sensitive adhesive composition and the release liner to the substrate. can also

The thickness of the pressure-sensitive adhesive layer is preferably 5 µm or more, more preferably 10 µm or more, and even more preferably 25 µm or more, from the viewpoint of the appearance when the optical layered body and the supporting substrate are bonded together. In addition, from the viewpoint of suppressing foaming generated by high-temperature heating, the thickness is preferably 100 μm or less, more preferably 75 μm or less, and even more preferably 50 μm or less.
The thickness of the adhesive layer can be measured with a dial gauge.

Various methods are used as a method for applying the pressure-sensitive adhesive composition. Specifically, for example, roll coating, kiss roll coating, gravure coating, reverse coating, roll brushing, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, die coater, etc. A method such as an extrusion coating method can be used.

The heat drying temperature is preferably 30°C to 200°C, more preferably 40°C to 180°C, and even more preferably 80°C to 160°C. By setting the heating temperature within the above range, a pressure-sensitive adhesive layer having excellent adhesive properties can be obtained. An appropriate drying time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 30 seconds to 10 minutes, even more preferably 1 minute to 8 minutes.

When the pressure-sensitive adhesive composition is an active energy ray-curable pressure-sensitive adhesive, the pressure-sensitive adhesive layer can be formed by irradiation with an active energy ray such as ultraviolet rays. A high-pressure mercury lamp, a low-pressure mercury lamp, a metal halide lamp, a chemical light lamp, or the like can be used for ultraviolet irradiation.

The adhesive layer in the optical laminate can be protected with a release liner (separator).
For example, when the optical layered body is shipped, the pressure-sensitive adhesive layer is protected by a release liner, and then the release liner is peeled off and bonded to the supporting substrate to manufacture the mirror member.

The release liner is not particularly limited as long as it can protect the pressure-sensitive adhesive layer. Appropriate thin sheets such as laminates can be used, but plastic films are preferably used because of their excellent surface smoothness.

Examples of the plastic film include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, and ethylene. - Vinyl acetate copolymer film and the like.

The thickness of the release liner is usually 5-200 μm, preferably 5-100 μm. For the release liner, if necessary, a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, release and antifouling treatment with silica powder, etc., coating type, kneading type, vapor deposition An antistatic treatment can also be applied to the mold or the like. In particular, by subjecting the surface of the release liner to a release treatment such as silicone treatment, long-chain alkyl treatment, fluorine treatment, etc., the releasability from the pressure-sensitive adhesive layer can be further enhanced.

The optical layered body 1 according to the embodiment of the present invention is preferably in the form of a film. Specifically, the substrate 10 is the substrate film described above, and the thickness of the optical laminate is preferably 6 μm to 250 μm, more preferably 20 μm to 100 μm.
When the optical layered body is in the form of a film, it can be attached to a support base material, so that a mirror member can be manufactured with high productivity even if the member has a complicated curved surface shape.

[Manufacture of optical laminate]
The method for manufacturing the optical layered body according to the embodiment of the present invention is not particularly limited. For example, when a substrate film is used as the substrate 10 to produce the optical laminate 1 shown in FIG. The low refractive index layer 13a, the high refractive index layer 13b, and the second low refractive index layer 13c can be formed in this order, and the functional layer 14 can be formed on the second low refractive index layer 13c.
The optical laminate may further comprise an adhesive layer, and the adhesive layer 12 may be directly formed by coating a composition capable of forming the adhesive layer 12 on the other surface of the base film. Alternatively, the adhesive layer 12 formed separately may be laminated.

The method of forming the metal reflective layer 11, the first low refractive index layer 13a, the high refractive index layer 13b, and the second low refractive index layer 13c is not particularly limited, but examples include a vacuum deposition method and a sputtering method. , an ion plating method, and the like. The sputtering method is preferable because the thickness can be strictly controlled even in a large area.

The method of forming the functional layer is not particularly limited, but for example, it can be formed by applying a solution containing an infrared absorber and a curable resin as a composition for forming the functional layer onto the second low refractive index layer 13c.

The optical layered body according to the embodiment of the present invention can be used as a mirror member.
Further, the optical layered body according to the embodiment of the present invention can also be used for decorating members. For example, it may be used by being attached to an adherend member, and as the adherend member, for example, a member made of glass or plastic can be used, but it is not limited to this.

[Mirror member]
A mirror member according to an embodiment of the present invention has the above optical layered body.
It is preferable that the mirror member according to the embodiment of the present invention includes the film-like optical layered body and a supporting substrate, and the optical layered body is attached to the supporting substrate via an adhesive layer. .
FIG. 3 is a schematic cross-sectional view of a mirror member according to one embodiment of the invention. A mirror member 100 shown in FIG. An optical layered body having a layer 13c) and a functional layer 14 in this order is attached to a support substrate 21 with an adhesive layer 12 interposed therebetween.
Since the mirror member according to the embodiment of the present invention can be produced by attaching it to a supporting substrate when using a film-like optical laminate, even a member having a complicated curved surface shape can be produced with high productivity. can be done.
A method for manufacturing a mirror member according to an embodiment of the present invention comprises the steps of: corona-treating at least a part of the surface of the supporting substrate; It may include a step of attaching to the supporting base material via.

<Support base material>
The material of the supporting substrate is not particularly limited, and examples thereof include resin, glass, metal, etc., and it is preferable to use resin. Examples of resins include polyester resins such as polyethylene terephthalate (PET), polybutylene terephthalate, and polyethylene naphthalate; (meth)acrylic resins (acrylic resins and/or methacrylic resins) such as polymethacrylate; , olefin resins such as cycloolefin polymers (e.g., norbornene-based, cyclopentadiene-based), e.g., polycarbonate resins, polyethersulfone resins, polyarylate resins, melamine resins, polyamide resins, polyimide resins, cellulose resins, polystyrene resins, etc. be done. These materials can be used singly or in combination of two or more. Among them, a polycarbonate resin is preferable from the viewpoint of light-shielding properties because it can be made black.

[Uses of Optical Laminate and Mirror Member]
Applications of the optical laminate and the mirror member according to the embodiments of the present invention include, for example, structural parts for vehicles, vehicle-mounted goods such as head-up displays, housings for electronic devices, housings for home appliances, structural parts, and machinery. parts, parts for various automobiles, parts for electronic equipment, household goods such as furniture and kitchen utensils, medical equipment, parts for building materials, other structural parts and exterior parts. More specifically, for vehicles, instrument panels, console boxes, door knobs, door trims, shift levers, pedals, glove boxes, bumpers, bonnets, fenders, trunks, doors, roofs, pillars, seats, steering wheels , ECU boxes, electrical components, engine peripheral parts, drive system/gear peripheral parts, intake/exhaust system parts, cooling system parts, and the like. More specifically, electronic devices and home appliances include home appliances such as refrigerators, washing machines, vacuum cleaners, microwave ovens, air conditioners, lighting equipment, electric water heaters, televisions, clocks, ventilation fans, projectors, speakers, personal computers, and mobile phones. , smart phones, digital cameras, tablet PCs, portable music players, portable game machines, battery chargers, electronic information devices such as batteries, and the like.
Among the above, it can be preferably used as a mirror member for a head-up display.

EXAMPLES The present invention will be described below based on Examples, but the present invention is not limited to these.

[Example 1]
[Base film]
As a base film, a PET film 50-U483 (thickness: 50 μm) manufactured by Toray Industries, Inc. was coated with an ultraviolet curable resin layer (hard coat layer) having a thickness of 1.5 μm to obtain a PET film with a hard coat layer.

[Preparation of metal reflective layer]
The Al target and the base film were set in a laboratory magnetron sputtering apparatus, and an aluminum layer (Al layer) having a thickness of 44 nm was formed as a metal reflective layer on the surface of the base film on the hard coat layer side.

[Preparation of optical adjustment layer]
A substrate film on which an Al layer is formed using a laboratory magnetron sputtering device is set in the magnetron sputtering device, and silicon oxide 67 nm (refractive index 1.46) is formed on the Al layer as a first low refractive index layer. , niobium oxide (Nb ₂ O ₅ ) 53 nm (refractive index 2.32) as a high refractive index layer, silicon oxide (SiO ₂ ) 40 nm (refractive index 1.46) as a second low refractive index layer, etc., in this order. An oxide thin film was formed as an optical adjustment layer. In the formation of thin films of silicon oxide and niobium oxide, a pure silicon target and a pure niobium target were used as targets, oxygen gas was introduced in addition to argon gas, and reactive sputtering was carried out to form transparent oxides. A thin film was obtained.

[Production of functional layer]
UV curable acrylic resin (V6850 manufactured by DIC Corporation), Irgacure 184 as a photocuring agent at a solid concentration of 3% by mass, and cesium-doped tungsten oxide YMF-02A manufactured by Sumitomo Metal Mining Co., Ltd. as an infrared absorber at a solid concentration of 1. A functional layer having a film thickness of 5 μm was formed by blending so as to make the mass %, coating on the optical adjustment layer, drying, and irradiating with ultraviolet rays.

As described above, on one side of a 51.5 μm hard coat layer-attached PET substrate (substrate film), silicon oxide 5 nm, aluminum 44 nm, silicon oxide 67 nm, niobium oxide 53 nm, silicon oxide 40 nm, and a functional layer 5 μm thin in this order. A film-like optical layered body 1 having layers formed thereon was produced.

[Production of mirror member]
A light release liner of an adhesive sheet CS9861UAS (manufactured by Nitto Denko Corporation) was peeled off, and a laminate was obtained by laminating the surface of the base film of the optical laminate 1 on which no sputter film was formed.
The heavy release liner on the pressure-sensitive adhesive layer side of the resulting laminate was peeled off, and the laminate was laminated to a 3.0 mm-thick polycarbonate substrate (Carboglass, black, manufactured by Asahi Glass Co., Ltd.) as a supporting substrate to prepare a mirror member. bottom. The size of the obtained mirror member is 50 mm×150 mm.

[Example 2]
An optical laminate and a mirror member were produced in the same manner as in Example 1, except that the concentration of the infrared absorbing agent was changed to 5% by mass and the film thickness of the functional layer was changed to 1.5 μm.

[Example 3]
In the same manner as in Example 1, except that the infrared absorbing agent was changed to FS-133 (CIR, phenylenediamine type manufactured by Nippon Carlit Co., Ltd.), the concentration was changed to 3% by mass, and the functional layer thickness was changed to 1.5 μm. An optical laminate and a mirror member were produced.

[Example 4]
An optical laminate and a mirror member were produced in the same manner as in Example 1, except that the concentration of the infrared absorbing agent was changed to 7% by mass and the film thickness of the functional layer was changed to 3.5 μm.

[Comparative Example 1]
An optical laminate and a mirror member were produced in the same manner as in Example 1, except that no functional layer was laminated.

[Comparative Example 2]
An optical laminate and a mirror member were produced in the same manner as in Example 1, except that the concentration of the infrared absorber was changed to 1% by mass and the film thickness of the functional layer was changed to 1.5 μm.

[Comparative Example 3]
An optical laminate and a mirror member were produced in the same manner as in Example 1, except that no infrared absorber was added.

<Infrared absorption rate>
A functional layer was coated on PET film 50-U483 manufactured by Toray Industries, Inc. under the same conditions as in Examples and Comparative Examples to obtain a transparent PET film with a functional layer. Infrared rays are incident on the functional layer side surface of the transparent PET film with a functional layer, and reflectance and transmittance are measured at a wavelength of 1000 nm using a Hitachi spectrophotometer U-4100 measurement device manufactured by Hitachi High-Tech Science Co., Ltd. A value obtained by subtracting the reflectance and the transmittance from 100% was defined as the infrared absorption rate.

<Reflectance>
For the optical laminates of each of the prepared examples and comparative examples, D65 was used as a standard light source, and a Hitachi spectrophotometer U-4100 manufactured by Hitachi High-Tech Science Co., Ltd. was used to measure the wavelength in the range of 380 nm to 780 nm. The reflectance Y (%) was measured for visible light.
In the measurement, the visible light was made incident on the functional layer side surface of the obtained optical layered body at an incident angle of 30°.
When the reflectance Y at a wavelength of 380 nm to 780 nm was 85% or more, it was evaluated as ◯ (good), when it was 80% or more and less than 85%, it was evaluated as Δ (acceptable), and when it was less than 80%, it was evaluated as x (poor).

<Solar reflectance>
For the optical layered bodies of each of the manufactured examples and comparative examples, the same measurement as the above reflectance measurement was performed in the wavelength range of 300 nm to 2500 nm. It was derived according to
The case where the solar reflectance was 82% or less was evaluated as ◯ (good), and the case where the solar reflectance exceeded 82% was evaluated as x (bad).

<Comprehensive evaluation>
As a comprehensive evaluation, ◯ (good) when the solar reflectance is 82% or less and the reflectance Y is 85% or more, and the solar reflectance is 82% or less and the reflectance Y is 80%. △ (acceptable) when it is 85% or more, × (poor) when the solar reflectance is 82% or less and the reflectance Y is less than 80%, and when the solar reflectance exceeds 82% and

The results are shown in Table 1 below. In Table 1, "infrared absorbing agent content" represents a numerical value calculated from the product of the concentration of the infrared absorbing agent and the film thickness of the functional layer.

As described above, the optical layered body of this example is excellent in visible light reflection performance and heat shielding property, and can be preferably applied to a mirror member.

The present invention is not limited to the above-described embodiments, but can be modified in various ways within the scope of the claims, and can be obtained by appropriately combining technical means disclosed in different embodiments. is also included in the technical scope of the present invention.

REFERENCE SIGNS LIST 1 optical laminate 10 substrate 11 metal reflective layer 12 adhesive layer 13 optical adjustment layer 13a first low refractive index layer 13b high refractive index layer 13c second low refractive index layer 14 functional layer 21 supporting substrate 100 mirror member

Claims (8)

a metal reflective layer, an optical adjustment layer, and a functional layer provided in this order on a substrate;
The optical adjustment layer includes at least one high refractive index layer having a refractive index of 1.75 or more,
An optical laminate having a solar reflectance of 82% or less. The optical laminate according to claim 1, wherein the functional layer contains an infrared absorber. 3. The optical laminate according to claim 2, wherein the functional layer contains 1 to 10% by mass of the infrared absorbing agent. 4. The optical layered product according to claim 2, wherein the infrared absorber contains cesium-doped tungsten oxide. The optical laminate according to any one of claims 1 to 4, which has a reflectance Y of 85% or more. The optical laminate according to any one of claims 1 to 5, wherein the metal reflective layer contains aluminum or an aluminum alloy. The optical laminate according to any one of claims 1 to 6, which is in the form of a film. A mirror member comprising the optical laminate according to any one of claims 1 to 7.

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