JP2022150261A - sheet material - Google Patents

Abstract

To provide a sheet material which can maintain high accuracy in wide angle scanning using near infrared rays.SOLUTION: A sheet material 10 is a resin sheet material transmitting near infrared rays, has a resin material having light transmissivity as a main material and a visible light transmission suppressing material for preventing the resin material from transmitting visible light, wherein when a transmittance when an incident angle of the near infrared rays to the surface of the sheet material body is 0 degree is represented by T1 (%), and a transmittance when the incident angle is 60 degrees is represented by T2 (%), the transmittances satisfy conditions (1) to (3). (1) T1>87.5%, (2) T2>79.0%, and (3) 0.8≤T2/T1≤1.2.SELECTED DRAWING: Figure 1

Description

The present invention relates to sheet material.

2. Description of the Related Art A sheet material (molded body) molded using a resin composition containing a permeable resin material as a main component (main material) is known. In particular, sheet materials mainly made of polycarbonate are used as cover members for various sensors and cameras in vehicles such as automobiles because of their excellent transparency and impact resistance.

As such a cover member, for example, for the purpose of selectively transmitting light having a wavelength in a specific wavelength region such as the near-infrared region, it allows transmission of light having a wavelength in a specific wavelength region. An optical layer (molding) to which a light absorbing agent having a light absorption characteristic capable of reducing the transmission of light having a wavelength in a specific wavelength region of is added (for example, see Patent Document 1).

JP 2013-227562 A

In recent years, in the field of automobiles, the development and marketing of ADAS (Advanced Driver-Assistance Systems) have rapidly progressed. ADAS requires technology to recognize the environment such as moving objects, structures, and road shapes around the vehicle, and is realized by combining various sensors. LiDAR is a very important sensor among such sensors. LiDAR is a type of sensor that uses laser light, and can accurately detect not only the distance to an object but also its position and shape, making it an essential technology for autonomous driving in urban areas. In order to achieve detection with higher accuracy, it is desirable to obtain sufficient signal strength even when performing wide-angle scanning.

An object of the present invention is to provide a sheet material that can maintain high accuracy in wide-angle scanning using near-infrared rays.

According to the present embodiment, a resin sheet material that transmits near-infrared rays,
A sheet material body including a resin material as a main material having translucency and a visible light transmission suppressing material for suppressing the transmission of visible light through the resin material,
When the transmittance is T1 (%) when the incident angle of the near-infrared rays with respect to the surface of the sheet material body is 0 degrees, and the transmittance is T2 (%) when the incident angle is 60 degrees, conditions (1) to (3) ) is provided.
(1) T1>87.5%
(2) T2>79.0%
(3) 0.8≤T2/T1≤1.2

According to the present invention, it is possible to provide a sheet material that can maintain high accuracy in wide-angle scanning using near-infrared rays.

It is a longitudinal section of the sheet material of a 1st embodiment. It is a longitudinal cross-sectional view of the sheet material of 2nd Embodiment. It is a longitudinal cross-sectional view of the sheet material of 3rd Embodiment. It is a longitudinal cross-sectional view of the sheet material of 4th Embodiment. It is a longitudinal section of the sheet material of a 5th embodiment. It is a longitudinal section of the sheet material of a 6th embodiment. FIG. 11 is a vertical cross-sectional view of a sheet member of a seventh embodiment;

Hereinafter, sheet materials according to embodiments of the present invention will be described with reference to the drawings.

<<First embodiment>>
FIG. 1 is a vertical cross-sectional view of a sheet material 10 of this embodiment, including a sensor light emitting/receiving portion 9 of an infrared sensor. In the following, for convenience of explanation, the upper side of FIG. 1 and FIGS. 2 to 6 described later will be referred to as "upper" and the lower side as "lower", and the sensor light emitting/receiving unit 9 is arranged on the lower side of the sheet material 10. be done.
Infrared laser light (hereinafter simply referred to as "laser light") is output with a certain spectral width, and in this embodiment, the wavelength (λ) is the wavelength at which the peak value is obtained. Moreover, "visible light" means an electromagnetic wave with a wavelength of 380 nm or more and 780 nm or less.

<Summary of sheet material 10>
The sheet material 10 is an optical laminated body, and is used as a cover member for covering the sensor light emitting/receiving portion 9 of the infrared sensor as shown in the drawing. An infrared sensor is installed in a remote sensing type measuring device that irradiates an object with a laser beam such as LiDAR, captures the reflected light with an optical sensor, and measures a distance. The sheet material 10 is used as a window portion through which the irradiated light or the reflected light of the laser light of such a measuring device is transmitted.

Since LiDAR scans by rotating the sensor light emitting/receiving unit 9, the horizontal scanning range may be a wide range such as an angle of 270°. Therefore, the laser light emitted from the sheet material 10 and the laser light incident thereon are required to have a high transmittance even when the emission angle and the incident angle are, for example, 60° or more. The illustration shows a laser beam L1 with an incident angle of 0° and a laser beam L2 with an incident angle of 60°. Therefore, in the present embodiment, a functional layer having low reflection characteristics is provided on the surface of the sheet material 10 to achieve high transmittance. Here, the fine concavo-convex layer 2 is exemplified as a functional layer having low reflection characteristics. That is, the sheet material 10 has a base material layer 1 as a sheet material main body and a fine concavo-convex layer 2 laminated on the upper surface of the base material layer 1, as shown in the drawing. A sensor light emitting/receiving portion 9 is provided so as to face the lower surface of the base material layer 1 .

According to the sheet material 10 having this configuration, the laser light output from the sensor light emitting/receiving unit 9 enters the inside of the sheet material 10 from the lower surface side of the base material layer 1 and passes through the base material layer 1 and the fine uneven layer 2. , and is output from the upper surface of the fine uneven layer 2 to the outside. Also, the laser light reflected by an object or the like passes through the opposite path, that is, the fine irregularity layer 2 and the substrate layer 1 and is received by the sensor light emitting/receiving portion 9 .

<Near-infrared transmittance>
In the sheet material 10, T1 (%) is the transmittance when the incident angle of the near-infrared laser light with respect to the surface of the sheet material main body, that is, the upper surface of the fine uneven layer 2 is 0 degrees, and the transmittance is 60 degrees. is T2 (%), the following conditions (1) to (3) are satisfied.
(1) T1>87.5%
(2) T2>79.0%
(3) 0.8≤T2/T1≤1.2
That is, the transmittance is high and does not change greatly whether the light is incident perpendicularly or obliquely to the sheet material 10 . As a result, the sensor light emitting/receiving unit 9 can perform stable sensing without large fluctuations in the detected value depending on the incident angle.

More specifically, when the wavelength of the laser light is 905 nm, the transmittance T1 is preferably 91% or more, more preferably 92% or more. The transmittance T2 is preferably 80% or more, more preferably 81% or more. The upper limits of the transmittances T1 and T2 are not particularly limited, but a practical value is 99% or less. The lower limit of T2/T1 is preferably 0.85 or more, more preferably 0.875 or more. The upper limit is preferably 1.1 or less, more preferably 1.0 or less.

When the wavelength of the laser light is 1550 nm, the transmittance T1 is preferably 88% or more, more preferably 90% or more. The transmittance T2 is preferably 81% or more, more preferably 82% or more. The upper limits of the transmittances T1 and T2 are not particularly limited, but a practical value is 99% or less. The lower limit of T2/T1 is preferably 0.85 or more, more preferably 0.90 or more. The upper limit is preferably 1.1 or less, more preferably 1.0 or less.

<Refractive index>
The refractive index of the surface of the sheet material 10, here, the refractive index of the fine uneven layer 2, is preferably 1.0 to 1.5. The upper limit of the refractive index is preferably less than 1.3. By setting the refractive index within such a range, the transmittance of the sheet material 10 for laser light can be increased.

<Contact angle>
The contact angle of water on the surface of the sheet material 10, here, the contact angle of the fine uneven layer 2 is preferably 90° or more and less than 180°. The lower limit of the contact angle is more preferably 100° or more, and even more preferably 130° or more. By setting the contact angle within such a range, the droplet removability on the surface of the sheet material 10 can be improved.

<Sliding angle>
The sliding angle of water on the surface of the sheet material 10, here, the sliding angle of the fine uneven layer 2 is preferably 1° or more and less than 30°. More preferably, the upper limit of the sliding angle is less than 5°. By setting the sliding angle within such a range, the droplet removability on the surface of the sheet material 10 can be improved. The sliding angle is the inclination angle at which the droplet starts to slide when the droplet is gradually inclined from a horizontal state.

A specific configuration of the sheet member 10 that achieves the near-infrared transmittance described above will be described below.
<Base material layer 1>
The base material layer 1 is formed into a layer using a resin composition containing a polycarbonate as a translucent main agent (main material) and a visible light absorber that is dissolved and dispersed in the polycarbonate and absorbs visible light. It is a compact. By including the visible light absorber in the resin composition, the transmission of visible light in a specific wavelength range is suppressed or prevented. Thereby, the sheet material 10 has a function of allowing transmission of light having a desired wavelength region.

(polycarbonate)
Polycarbonate (polycarbonate-based resin) is included as a main component (base resin) of the substrate layer 1 and is used to mold the substrate layer 1 into a substrate.

This polycarbonate is characterized by high mechanical strength such as transparency (translucency), rigidity, and impact resistance. Due to this feature, by using polycarbonate as the base material of the base material layer 1, the sheet material 10 can be made excellent in transparency and mechanical strength.
Further, since polycarbonate has a specific gravity of about 1.2 and is classified as a light material among known resin materials, the weight of the sheet member 10 can be reduced.

Various polycarbonates can be used as this polycarbonate, and examples thereof include bisphenol-type polycarbonates and isosorbide-derived polycarbonates produced using plant-derived isosorbide as a main component. preferable. The bisphenol-type polycarbonate has benzene rings in its main chain, which makes it possible to improve the strength of the sheet material 10 .

This bisphenol-type polycarbonate is synthesized, for example, by interfacial polycondensation reaction between bisphenol and phosgene, transesterification reaction between bisphenol and diphenyl carbonate, and the like.

Examples of bisphenol include bisphenol A and bisphenol (modified bisphenol) that is the origin of repeating units of polycarbonate represented by the following formula (A).

（式（Ａ）中、Ｘは、炭素数１～１８のアルキル基、芳香族基または環状脂肪族基であり、ＲａおよびＲｂは、それぞれ独立して、炭素数１～１２のアルキル基であり、ｍおよびｎは、それぞれ０～４の整数であり、ｐは、繰り返し単位の数である。）

(In formula (A), X is an alkyl group having 1 to 18 carbon atoms, an aromatic group or a cycloaliphatic group, and Ra and Rb are each independently an alkyl group having 1 to 12 carbon atoms. , m and n are each integers from 0 to 4, and p is the number of repeating units.)

Specific examples of the bisphenol, which is the source of the repeating unit of the polycarbonate represented by the formula (A), include 4,4′-(pentane-2,2-diyl)diphenol, 4,4′-( pentane-3,3-diyl)diphenol, 4,4'-(butane-2,2-diyl)diphenol, 1,1'-(cyclohexanediyl)diphenol, 2-cyclohexyl-1,4-bis( 4-hydroxyphenyl)benzene, 2,3-biscyclohexyl-1,4-bis(4-hydroxyphenyl)benzene, 1,1′-bis(4-hydroxy-3-methylphenyl)cyclohexane, 2,2′- Bis(4-hydroxy-3-methylphenyl)propane and the like can be mentioned, and one or more of these can be used in combination.

The content of polycarbonate in the sheet material 10 is not particularly limited, but is preferably 75 wt % or more, more preferably 85 wt % or more. By setting the polycarbonate content within the above range, the sheet material 10 can exhibit excellent strength.

(Visible light absorber)
Visible light absorbers suppress or prevent the transmission of visible light in specific wavelength regions. Since the visible light absorbing agent is substantially uniformly contained in the base material layer 1 in a dissolved/dispersed state, the base material layer 1 exhibits a function of allowing transmission of light having a desired wavelength range.

Such visible light absorbers are not particularly limited, but for example, a first light absorber that absorbs light with a wavelength of 300 nm or more and 550 nm or less, a second light absorber that absorbs light with a wavelength of 450 nm or more and 800 nm or less, A third light-absorbing agent that absorbs light having a wavelength of 400 nm or more and 800 nm or less is exemplified. It is possible to reliably provide the function of allowing permeation. Therefore, the sheet material 10 (cover member) exhibits light transmittance of transmitting light having a desired wavelength range.

The first light absorbing agent has absorption wavelength characteristics of absorbing light with a wavelength of 300 nm or more and 550 nm or less. Examples of the first light absorber include quinoline dyes.

Examples of quinoline dyes include 2-methylquinoline, 3-methylquinoline, 4-methylquinoline, 6-methylquinoline, 7-methylquinoline, 8-methylquinoline, 6-isopropylquinoline, 2,4-dimethylquinoline, Alkyl-substituted quinoline compounds such as 2,6-dimethylquinoline and 4,6,8-trimethylquinoline, 2-aminoquinoline, 3-aminoquinoline, 5-aminoquinoline, 6-aminoquinoline, 8-aminoquinoline, 6-amino -Amino group-substituted quinoline compounds such as 2-methylquinoline, alkoxy group-substituted quinoline compounds such as 6-methoxy-2-methylquinoline and 6,8-dimethoxy-4-methylquinoline, 6-chloroquinoline, 4,7-dichloro Examples thereof include halogen group-substituted quinoline compounds such as quinoline, 3-bromoquinoline, and 7-chloro-2-methylquinoline, and these can be used singly or in combination of two or more.

By blending such a first light absorbing agent as a visible light absorbing agent, it is possible for the base layer 1 to reliably absorb light having a wavelength of 300 nm or more and 550 nm or less among the light incident on the base layer 1. can.

The content of the first light absorbing agent in the base material layer 1 is not particularly limited, but is preferably 0.001 wt% or more and 10 wt% or less, more preferably 0.002 wt% or more and 1.0 wt% or less. , 0.005 wt % or more and 0.3 wt % or less. When the content of the first light absorbing agent in the base material layer 1 is less than the lower limit, depending on the type of the first light absorbing agent, visible light (light with a wavelength of 300 nm or more and 550 nm or less) of the base layer 1 absorption may decrease. Further, even if the content of the first light-absorbing agent in the substrate layer 1 exceeds the upper limit, no further improvement in the absorption of visible light (light having a wavelength of 300 nm or more and 550 nm or less) is observed, and the substrate The adhesiveness of the material layer 1 to the fine unevenness layer 2 may be impaired.

The second light absorbing agent has absorption wavelength characteristics of absorbing light with a wavelength of 450 nm or more and 800 nm or less. Examples of the second light absorber include anthraquinone dyes.

Examples of anthraquinone dyes include (1) 2-anilino-1,3,4-trifluoroanthraquinone, (2) 2-(o-ethoxycarbonylanilino)-1,3,4-trifluoroanthraquinone, ( 3) 2-(p-ethoxycarbonylanilino)-1,3,4-trifluoroanthraquinone, (4) 2-(m-ethoxycarbonylanilino)-1,3,4-trifluoroanthraquinone, (5) 2-(o-cyanoanilino)-1,3,4-trifluoroanthraquinone, (6) 2-(p-cyanoanilino)-1,3,4-trifluoroanthraquinone, (7) 2-(m-cyanoanilino)- 1,3,4-trifluoroanthraquinone, (8) 2-(o-nitroanilino)-1,3,4-trifluoroanthraquinone, (9) 2-(p-nitroanilino)-1,3,4-trifluoro anthraquinone, (10) 2-(m-nitroanilino)-1,3,4-trifluoroanthraquinone, (11) 2-(p-tert-butylanilino)-1,3,4-trifluoroanthraquinone, (12 ) 2-(o-methoxyanilino)-1,3,4-trifluoroanthraquinone, (13) 2-(2,6-diisopropylanilino)-1,3,4-trifluoroanthraquinone, (14) 2 -(2,6-dichloroanilino)-1,3,4-trifluoroanthraquinone, (15) 2-(2,6-difluoroanilino)-1,3,4-trifluoroanthraquinone, (16) 2 -(3,4-dicyanoanilino)-1,3,4-trifluoroanthraquinone, (17) 2-(2,4,6-trichloroanilino)-1,3,4-trifluoroanthraquinone, (18) 2 -(2,3,5,6-tetrachloroanilino)-1,3,4-trifluoroanthraquinone, (19) 2-(2,3,5,6-tetrafluoroanilino)-1,3, 4-trifluoroanthraquinone, (20) 3-(2,3,4,5-tetrafluoroanilino)-2-butoxy-1,4-difluoroanthraquinone, (21) 3-(4-cyano-3-chloroanilino )-2-octyloxy-1,4-difluoroanthraquinone, (22) 3-(3,4-dicyanoanilino)-2-hexyloxy-1,4-difluoroanthraquinone, (23) 3-(4-cyano-3 -chloroanilino)-1,2-dibutoxy-4-fluoroanthraquinone, (24) 3-(p-sia noanilino)-2-phenoxy-1,4-difluoroanthraquinone, (25) 3-(p-cyanoanilino)-2-(2,6-diethylphenoxy)-1,4-difluoroanthraquinone, (26) 3-(2 ,6-dichloroanilino)-2-(2,6-dichlorophenoxy)-1,4-difluoroanthraquinone, (27) 3-(2,3,5,6-tetrachloroanilino)-2-(2 ,6-dimethoxyphenoxy)-1,4-difluoroanthraquinone, (28) 2,3-dianilino-1,4-difluoroanthraquinone, (29) 2,3-bis(p-tert-butylanilino)-1, 4-difluoroanthraquinone, (30) 2,3-bis(p-methoxyanilino)-1,4-difluoroanthraquinone, (31) 2,3-bis(2-methoxy-6-methylanilino)-1,4- difluoroanthraquinone, (32) 2,3-bis(2,6-diisopropylanilino)-1,4-difluoroanthraquinone, (33) 2,3-bis(2,4,6-trichloroanilino)-1, 4-difluoroanthraquinone, (34) 2,3-bis(2,3,5,6-tetrachloroanilino)-1,4-difluoroanthraquinone, (35) 2,3-bis(2,3,5, 6-tetrafluoroanilino)-1,4-difluoroanthraquinone, (36) 2,3-bis(p-cyanoanilino)-1-methoxyethoxy-4-fluoroanthraquinone, (37) 2-(2,6-dichloro anilino)-1,3,4-trichloroanthraquinone, (38) 2-(2,3,5,6-tetrafluoroanilino)-1,3,4-trichloroanthraquinone, (39) 3-(2, 6-dichloroanilino)-2-(2,6-dichlorophenoxy)-1,4-dichloroanthraquinone, (40) 2-(2,6-dichloroanilino)anthraquinone, (41) 2-(2,3 ,5,6-tetrafluoroanilino)anthraquinone, (42) 3-(2,6-dichloroanilino)-2-(2,6-dichlorophenoxy)anthraquinone, (43) 2,3-bis(2- Methoxy-6-methylanilino)-1,4-dichloroanthraquinone, (44) 2,3-bis(2,6-diisopropylanilino)anthraquinone, (45) 2-butylamino-1,3,4-trifluoroanthraquinone , (46) 1,4-bis(n-butylamino)-2,3-difluoroanthraquinone , (47) 1,4-bis(n-octylamino)-2,3-difluoroanthraquinone, (48) 1,4-bis(hydroxyethylamino)-2,3-difluoroanthraquinone, (49) 1,4 -bis(cyclohexylamino)-2,3-difluoroanthraquinone, (50) 1,4-bis(cyclohexylamino)-2-octyloxy-3-fluoroanthraquinone, (51) 1,2,4-tris(2, 4-dimethoxyphenoxy-3-fluoroanthraquinone, (52) 2,3-bis(phenylthio)-1-phenoxy-4-fluoroanthraquinone, (53) 1,2,3,4-tetra(p-methoxyphenoxy)- Anthraquinone and the like can be mentioned, and one or more of these can be used in combination.

By blending such a second light absorbing agent as a visible light absorbing agent, it is possible for the base layer 1 to reliably absorb light having a wavelength of 450 nm or more and 800 nm or less among the light incident on the base layer 1. can.

The content of the second light absorbing agent in the base material layer 1 is not particularly limited, but is preferably 0.001 wt% or more and 10 wt% or less, and more preferably 0.002 wt% or more and 1.0 wt% or less. , 0.005 wt % or more and 0.6 wt % or less. When the content of the second light absorbing agent in the base material layer 1 is less than the lower limit value, visible light (light having a wavelength of 450 nm or more and 800 nm or less) of the base material layer 1 may occur depending on the type of the second light absorbing agent. absorption may be reduced. Further, even if the content of the second light-absorbing agent in the substrate layer 1 exceeds the above upper limit, no further improvement in absorption of visible light (light having a wavelength of 450 nm or more and 800 nm or less) is observed. The adhesion of the material layer 1 to the fine uneven layer 2 may be impaired.

The third light absorbing agent has an absorption wavelength characteristic of absorbing light with a wavelength of 400 nm or more and 800 nm or less. Examples of the third light absorber include perinone dyes.

Perinone dyes include, for example, 2,3-naphthaloperinone, 1,8-naphthaloperinone, tetrabromo-1,2-naphthaloperinone and the like, and one or more of these may be used in combination.

By blending such a perinone-based dye, it is possible for the base layer 1 to reliably absorb light having a wavelength of 400 nm or more and 800 nm or less among the lights incident on the base layer 1 .

The content of the third light absorbing agent in the base material layer 1 is not particularly limited, but is preferably 0.001 wt% or more and 10 wt% or less, more preferably 0.002 wt% or more and 1.0 wt% or less. , 0.005 wt % or more and 0.6 wt % or less. If the content of the third light-absorbing agent in the base layer 1 is less than the lower limit value, visible light (light with a wavelength of 400 nm or more and 800 nm or less) of the base layer 1 may occur depending on the type of the third light-absorbing agent. absorption may be reduced. Further, even if the content of the third light-absorbing agent in the base material layer 1 exceeds the upper limit, no further improvement in absorption of visible light (light having a wavelength of 400 nm or more and 800 nm or less) is observed. The adhesion of the material layer 1 to the fine uneven layer 2 may be impaired.

The substrate layer 1 preferably contains an ultraviolet absorber in addition to the visible light absorber. As a result, deterioration of the resin material and visible light absorbent contained in the base material layer 1, as well as the object to be covered with the sheet material 10 (cover member) due to ultraviolet rays can be suppressed or prevented accurately. Therefore, the base layer 1 can be made excellent in weather resistance.
In addition, the ultraviolet absorber may be contained in the fine uneven layer 2 .

Although the ultraviolet absorber is not particularly limited, it preferably contains a light absorber that absorbs light with a wavelength of 100 nm or more and 400 nm or less. As a result, it is possible to suppress the transmission of ultraviolet rays and visible light with relatively short wavelengths (light with a wavelength of 400 nm or less). Therefore, the function as an ultraviolet absorber can be exhibited reliably.

Examples of the ultraviolet absorber include, but are not limited to, triazine-based compounds, benzophenone-based compounds, benzotriazole-based compounds, and cyanoacrylate-based compounds. One or more of these may be used in combination. . Among these, triazine-based compounds are particularly preferred. As a result, deterioration of the base material layer 1 due to ultraviolet rays can be more reliably prevented or suppressed, and the weather resistance of the sheet material 10 can be further enhanced.

Examples of triazine compounds include 2-mono(hydroxyphenyl)-1,3,5-triazine compounds, 2,4-bis(hydroxyphenyl)-1,3,5-triazine compounds, 2,4,6- tris(hydroxyphenyl)-1,3,5-triazine compounds, specifically 2,4-diphenyl-6-(2-hydroxy-4-methoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-ethoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-(2-hydroxy-4-propoxyphenyl)-1,3,5- triazine, 2,4-diphenyl-(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-butoxyphenyl)-1,3, 5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-hexyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-octyloxyphenyl )-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-dodecyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy -4-benzyloxyphenyl)-1,3,5-triazine, 2,4-diphenyl-6-(2-hydroxy-4-butoxyethoxy)-1,3,5-triazine, 2,4-bis(2 -hydroxy-4-butoxyphenyl)-6-(2,4-dibutoxyphenyl)-1,3-5-triazine, 2,4,6-tris(2-hydroxy-4-methoxyphenyl)-1,3 ,5-triazine, 2,4,6-tris(2-hydroxy-4-ethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-propoxyphenyl)-1 ,3,5-triazine, 2,4,6-tris(2-hydroxy-4-butoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-hexyloxyphenyl )-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-octyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4 -dodecyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-benzyloxyphenyl)-1,3,5-triazine, 2,4,6- tris(2-hydroxy-4-ethoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-butoxyethoxyphenyl)-1,3,5-triazine, 2, 4,6-tris(2-hydroxy-4-propoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-methoxycarbonylpropyloxyphenyl)-1,3, 5-triazine, 2,4,6-tris(2-hydroxy-4-ethoxycarbonylethyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-4-(1- (2-ethoxyhexyloxy)-1-oxopropan-2-yloxy)phenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-methoxyphenyl)- 1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-ethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy- 3-methyl-4-propoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-butoxyphenyl)-1,3,5-triazine, 2, 4,6-tris(2-hydroxy-3-methyl-4-hexyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-octyloxyphenyl) )-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-dodecyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2 -hydroxy-3-methyl-4-benzyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-ethoxyethoxyphenyl)-1,3,5 -triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-butoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl- 4-propoxyethoxyphenyl)-1,3,5-triazine, 2,4,6-tris(2-hydroxy-3-methyl-4-methoxycarbonylpropyloxyphenyl)-1,3,5-triazine, 2, 4,6-tris(2-hydroxy-3-methyl-4-ethoxycarbonylethyloxyphenyl)-1,3,5-triazine, 2,4,6-tris(2- hydroxy-3-methyl-4-(1-(2-ethoxyhexyloxy)-1-oxopropan-2-yloxy)phenyl)-1,3,5-triazine and the like. In addition, commercial products of triazine-based ultraviolet absorbers include, for example, "TINUVIN 1577", "TINUVIN 460", "TINUVIN 477" (manufactured by BASF Japan), "ADEKA STAB LA-F70" (manufactured by ADEKA), etc. Among these, can be used in combination of one or more.

By blending such an ultraviolet absorber, it is possible to reliably absorb light with a wavelength of 100 nm or more and 400 nm or less among the light incident on the sheet material 10 .

When the base material layer 1 contains an ultraviolet absorber, the content of the ultraviolet absorber in the base material layer 1 is preferably 0.005 wt% or more and 0.200 wt% or less, and more preferably 0.008 wt% or more and 0.150 wt%. % or less. If the content of the ultraviolet absorber in the base material layer 1 is less than the above lower limit, the weather resistance of the base material layer 1 may deteriorate depending on the type of the ultraviolet absorber. Further, even if the content of the ultraviolet absorber in the substrate layer 1 exceeds the upper limit, no further improvement in weather resistance is observed, and the adhesion of the substrate layer 1 to the fine uneven layer 2 may be impaired. There is

The substrate layer 1 may contain a pigment (for example, an infrared light absorbing agent, etc.) different from the visible light absorbing agents listed above. Examples of the coloring matter include, but are not limited to, pigments, dyes, and the like, and these can be used singly or in combination.

Examples of pigments include, but are not limited to, phthalocyanine-based pigments such as phthalocyanine green and phthalocyanine blue, fast yellow, disazo yellow, condensed azo yellow, benzimidazolone yellow, dinitroaniline orange, benzimidazolone orange, toluidine red, and permanents. Azo pigments such as carmine, permanent red, naphthol red, condensed azo red, benzimidazolone carmine, benzimidazolone brown; anthraquinone pigments such as anthrapyrimidine yellow and anthraquinonyl red; azomethine pigments such as copper azomethine yellow; Quinophthalone pigments such as yellow, isoindoline pigments such as isoindoline yellow, nitroso pigments such as nickeldioxime yellow, perinone pigments such as perinone orange, quinacridone pigments such as quinacridone magenta, quinacridone maroon, quinacridone scarlet, and quinacridone red. perylene pigments such as perylene red and perylene maroon, pyrrolopyrrole pigments such as diketopyrrolopyrrole red, organic pigments such as dioxazine pigments such as dioxazine violet, carbon black, lamp black, furnace black, ivory Carbon-based pigments such as black, graphite, and fullerene; chromate-based pigments such as yellow lead and molybdate orange; , sulfide pigments such as sulfide, ocher, titanium yellow, titanium barium nickel yellow, red iron oxide, red lead, amber, brown iron oxide, zinc iron chrome brown, chromium oxide, cobalt green, cobalt chrome green, titanium cobalt green, cobalt Oxide pigments such as blue, cerulean blue, cobalt aluminum chrome blue, iron black, manganese ferrite black, cobalt ferrite black, copper chrome black, copper chromium manganese black, hydroxide pigments such as Viridian, ferrocyanine such as Prussian blue compound pigments, silicate pigments such as ultramarine blue, phosphate pigments such as cobalt violet and mineral violet, and other inorganic pigments (such as cadmium sulfide, cadmium selenide, etc.). can be used in combination of one or more.

Examples of dyes include, but are not limited to, metal complex dyes, cyan dyes, xanthene dyes, azo dyes, hibiscus dyes, blackberry dyes, raspberry dyes, pomegranate juice dyes, chlorophyll dyes, and the like. One of them or two or more of them can be used in combination.

By appropriately setting the combination of the visible light absorber, the ultraviolet absorber, and the types of dyes different from these, and the content thereof, the substrate layer 1 can transmit light having a desired wavelength region. It is possible to exhibit the function of selectively allowing

The base material layer 1 preferably has a transmittance of 85% to 95%, preferably 86% or more, for light (infrared light) in a wavelength range of 850 nm or more and 1100 nm or less or light in a wavelength range of 1500 nm or more and 1600 nm or less. It is more preferably 93% or less.

As a result, the sheet material 10 can be suitably used as a cover member for covering the light emitting/receiving portion of an infrared sensor or an infrared camera.

Although the thickness of the base layer 1 is not particularly limited, it is preferably 0.1 mm or more and 3 mm or less, and more preferably 0.5 mm or more and 2.5 mm or less. As a result, the base material layer 1 can sufficiently exhibit its effect as a base material layer, and prevents cracks from occurring in the fine uneven layer 2 when the sheet material 10 is molded into a curved surface shape. be able to.

<Fine irregularity layer 2>
The fine unevenness layer 2 has a fine unevenness structure having periodicity in unevenness. The period of the unevenness can be, for example, 800 nm or less. A preferable range of the period of the unevenness is 1 time or less, preferably 1/2 or less, with respect to the wavelength λnm of the target laser light (infrared rays).

For example, when used as a cover member for a device that emits laser light with a wavelength of 905 nm, the period of the irregularities can be 905 nm or less, preferably 452.5 nm or less. When used as a cover member for a device emitting a laser beam of 1550 nm, the period of the irregularities can be 1550 nm or less, more preferably 775 nm or less. Although the lower limit is not particularly limited, it is, for example, 50 nm as a realistic value.
By setting the period of the unevenness within such a range, the transmittance of the laser light can be increased. That is, when the sheet material 10 having the fine uneven layer 2 is applied to LiDAR or the like, the detection distance can be extended. In addition, an antifouling and water repellent effect can be realized.

The height of the projections of the fine uneven structure (that is, the height difference between the projections and the recesses) is 100 to 400 nm. The lower limit is preferably 150 nm or more, more preferably 200 nm or more. The upper limit is 350 nm or less, more preferably 300 nm or less.
By setting the height of the projections of the fine concavo-convex structure to such a range, the transmittance of laser light can be increased. That is, when the sheet material 10 having the fine uneven layer 2 is applied to LiDAR or the like, the detection distance can be extended. In addition, a high antifouling and water repellent effect can be achieved.

Examples of the fine irregularity layer 2 having periodicity in irregularities include a moth-eye layer and a fine irregularity film layer made of nanoparticles. Here, an example in which a moth-eye layer is applied will be described.

The fine concavo-convex layer 2 is laminated on the base material layer 1 to cover the base material layer 1 . An adhesive or pressure-sensitive adhesive is used for bonding the base material layer 1 and the fine uneven layer 2 . The fine uneven layer 2 is a low-reflection layer with relatively low reflectance, that is, relatively high transmittance. By covering the upper surface of the base material layer 1 with the fine uneven layer 2 having this moth-eye structure, the sheet material 10 can be provided with superior light transmittance, antifogging properties, and antifouling properties. That is, it is possible to improve the efficiency of taking in light through the sheet material 10 from the outside of the device such as LiDAR to the inside of the device.

The moth-eye structure will be explained. The moth-eye structure is a surface microstructure having a fine uneven pattern on the surface. It has a plurality of fine protrusions having a shape, and the protrusions are arranged randomly on the surface of the fine uneven layer 2 .

In this moth-eye structure, the period (pitch) of the concave-convex pattern is set to be equal to or less than the wavelength of the laser light (infrared rays) transmitted through the base material layer 1 (sheet material 10), preferably equal to or less than half the wavelength, and , By setting the height of the protrusions (convex portions) to the wavelength of the light to be transmitted through the substrate layer 1 or more, preferably 1/2 or more of the wavelength, it is possible to accurately reflect the light on the fine uneven layer 2. The light transmittance of the sheet material 10 can be improved by suppressing or preventing it.

Thus, the plurality of projections in the moth-eye structure, that is, the uneven pattern is appropriately set according to the wavelength of the light (infrared rays) that is transmitted through the base material layer 1 (the sheet material 10). The average height of the projections and the average pitch (cycle) between the projections are set within the ranges described above.

Although the thickness of the fine uneven layer 2 is not particularly limited, for example, it is preferably 0.5 μm or more and 20 μm or less, and more preferably 3.0 μm or more and 15 μm or less. If the thickness of the fine uneven layer 2 becomes too thin, the strength of the fine uneven layer 2 may decrease depending on the type of material constituting the fine uneven layer 2, and the fine uneven layer 2 may be broken or cracked. is not desirable. On the other hand, if the thickness of the finely uneven layer 2 is too thick, depending on the type of material constituting the finely uneven layer 2, the light transmittance and flexibility of the sheet material 10 may be lowered, which is preferable. do not have.

The fine uneven layer 2 may be composed of any constituent material as long as it has optical transparency, but it is composed of a cured product of a photocurable resin composition containing a photocurable resin. is preferred. As a result, the fine uneven layer 2 having a moth-eye structure can be relatively easily formed on the substrate layer 1 by using a method for forming a moth-eye structure using a reversal transfer type, which will be described later.

The photocurable resin is not particularly limited as long as it is cured by irradiation with light such as ultraviolet rays. Examples include acrylic resins, cyclic olefin resins, epoxy resins, urethane resins, and vinylphenol resins. etc., and one or more of these may be used in combination. Among these, at least one of acrylic resin and cyclic olefin resin is preferable. Since acrylic resins and cyclic olefin resins have a high curing speed when irradiated with light, a moth-eye structure can be formed quickly with a relatively small amount of exposure in the method of forming a moth-eye structure.

Moreover, the photocurable resin composition preferably contains a photopolymerization initiator such as benzophenone, acetophenone, benzoin, and benzoin isobutyl ether. As a result, the patterning property of the cured product of the resin composition is improved by photopolymerization by light irradiation, so that a fine moth-eye structure can be formed.

Furthermore, in addition to the photocurable resin and the photopolymerization initiator, the photocurable resin composition may contain additives such as fillers, plastic resins, leveling agents, antifoaming agents, and coupling agents. good.

By having a moth-eye structure, the fine concavo-convex layer 2 having the structure described above exhibits excellent light transmittance by reducing the reflectance of the surface. The reflectance for infrared rays having a wavelength range is preferably set to 6% or less, more preferably 3% or less, and even more preferably 1% or less. Thereby, the sheet material 10 exhibits excellent light transmittance.

<Moving body (vehicle)>
By providing the moving body with the sheet material 10 as described above as a cover member that covers the sensor light emitting/receiving unit 9 of a device such as LiDAR, detection accuracy can be improved, leading to improved functions such as ADAS.

A moving body having the sheet material 10 (optical laminate) as a cover member can be used for predetermined work in automobiles, two-wheeled vehicles (motorcycles, bicycles), ships, railroad vehicles, airplanes, buses, forklifts, construction sites, and the like. It may be a working vehicle, a golf cart, an unmanned guided vehicle, an unmanned aircraft, or the like.

<<Second Embodiment>>
FIG. 2 is a longitudinal sectional view of the sheet material 10A of this embodiment. Hereinafter, the sheet material 10A of the present embodiment will be described with a focus on the differences from the sheet material 10 of the above-described first embodiment, and the description of the same items will be omitted as appropriate.
A sheet material 10A of the present embodiment is provided with a low-reflection layer 3 instead of the fine uneven layer 2 of the first embodiment. The low-reflection layer 3 will be mainly described below.

<Low reflection layer 3 (multilayer interference structure layer)>
The low-reflection layer 3 has a multilayer interference structure, and has a high-refractive-index layer 31 and a low-refractive-index layer 32 .

<High refractive index layer 31>
The high refractive index layer 31 is a layer that forms an antireflection layer together with a low refractive index layer 32 described later, and has a higher refractive index than the hard coat layer and the low refractive index layer 32 that serve as a base. The high refractive index layer 31 develops an antireflection effect due to a significant difference in refractive index from the low refractive index layer 32 . The refractive index of the high refractive index layer 31 is 1.50 to 1.65. When the refractive index of the high refractive index layer 31 is less than 1.50, the refractive index difference with the low refractive index layer 32 is too small, and the reflection at the interface between the high refractive index layer 31 and the low refractive index layer 32 is weak. As a result, the antireflection performance may not be sufficiently exhibited. When the refractive index of the high refractive index layer 31 exceeds 1.65, the reflection at the interface between the high refractive index layer 31 and the low refractive index layer 32 becomes strong, and the reflected light tends to be colored strongly. The film thickness of the high refractive index layer 31 is 130 to 180 nm. If the thickness of the high refractive index layer 31 is out of the above range, the interference balance with other layers may be lost, causing an increase in reflectance, and sufficient antireflection properties may not be obtained.

<Composition for forming high refractive index layer>
The high refractive index layer 31 is formed by applying a high refractive index layer coating liquid composed of a composition for forming a high refractive index layer containing an active energy ray-curable resin and metal oxide fine particles onto the hard coat layer and then curing the coating liquid. can get.

(Active energy ray-curable resin)
The active energy ray-curable resin is not particularly limited as long as it is a polyfunctional (meth)acrylate that undergoes a curing reaction when irradiated with an active energy ray (ultraviolet rays, electron beams, etc.). Examples of the polyfunctional (meth)acrylate include dipentaerythritol hexa(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, 1,6 -Hexanediol di(meth)acrylate, polyfunctional alcohol (meth)acryl derivatives such as 1,6-bis(3-(meth)acryloyloxy-2-hydroxypropyloxy)hexane, polyethylene glycol di(meth)acrylate, polyurethane (meth)acrylate and the like.

(metal oxide fine particles)
Metal oxide fine particles are added to adjust the refractive index of the high refractive index layer. Metal oxide fine particles include fine particles such as zinc antimonate, zinc oxide, titanium oxide, cerium oxide, aluminum oxide, tantalum oxide, yttrium oxide, ytterbium oxide, zirconium oxide, indium tin oxide, silicon oxide, and antimony-containing tin oxide. is mentioned. In particular, conductive fine particles such as zinc antimonate, indium tin oxide, and antimony-containing tin oxide are preferable from the viewpoint of being able to reduce the surface resistivity and impart antistatic properties. Moreover, titanium oxide is preferable from the viewpoint of adjusting the refractive index of the high refractive index layer to a higher value. On the other hand, silicon oxide is preferable from the viewpoint of lowering the refractive index of the high refractive index layer.

The content of the metal oxide fine particles is preferably 90% by mass or less. When the content of the metal oxide fine particles exceeds 90% by mass, the content of the active energy ray-curable resin becomes relatively small, and the high refractive index layer becomes brittle.

<Composition for forming low refractive index layer>
The low refractive index layer can be obtained by applying a low refractive index layer coating liquid comprising a composition for forming a low refractive index layer onto the high refractive index layer and then curing the coating solution. The composition for forming a low refractive index layer contains an active energy ray-curable resin and hollow silica fine particles. The active energy ray-curable resin that forms the low refractive index layer is not particularly limited as long as it is a polyfunctional (meth)acrylate. As the resin for forming this type of low refractive index layer, a composition containing a polyfunctional (meth)acrylate as a main component is preferable from the viewpoint of achieving both productivity and hardness.

(Active energy ray-curable resin)
The active energy ray-curable resin is not particularly limited as long as it is a polyfunctional (meth)acrylate that undergoes a curing reaction when irradiated with an active energy ray (ultraviolet rays, electron beams, etc.). Examples of the polyfunctional (meth)acrylate include dipentaerythritol hexa(meth)acrylate, tetramethylolmethane tetra(meth)acrylate, tetramethylolmethane tri(meth)acrylate, trimethylolpropane tri(meth)acrylate, 1,6 -Hexanediol di(meth)acrylate, polyfunctional alcohol (meth)acryl derivatives such as 1,6-bis(3-(meth)acryloyloxy-2-hydroxypropyloxy)hexane, polyethylene glycol di(meth)acrylate, polyurethane (meth)acrylate and the like.

The active energy ray-curable polyfunctional (meth)acrylate may be a fluorine-containing monomer. A fluorine-containing monomer having a structure in which a fluorine atom is introduced into the molecule as a methylene fluoride group or a fluorinated methine group is a monomer in which almost all of the fluorine atoms are introduced into the molecule as a methylene fluoride group or a fluorinated methine group. and all known monomers can be used as long as they are polyfunctional monomers. In other words, it may be any two or more (polyfunctional) monomers, or a mixture thereof. These fluorine-containing compounds can increase the strength and hardness of the cured film, and can improve the scratch resistance and abrasion resistance of the surface of the cured film. Among the fluorine-containing compounds, fluorine-containing polyfunctional (meth)acrylates are preferable from the viewpoint of being able to form a crosslinked structure and from the viewpoint of the strength and hardness of the cured film being high.

In the hollow silica fine particles, the hollow portion of the hollow silica fine particles preferably has a porosity of 40 to 45%. If the porosity of the hollow silica fine particles is less than 40%, the refractive index of the hollow silica fine particles themselves becomes high, and the refractive index of the low refractive index layer cannot be significantly lowered, or the content of the hollow silica fine particles must be increased. . As a result, the low refractive index layer becomes brittle. When the porosity exceeds 45%, the hollow silica fine particles themselves become brittle. The average particle diameter of the hollow silica fine particles is preferably equal to or less than the film thickness of the low refractive index layer, specifically 10 to 100 nm. In addition, from the viewpoint of improving the dispersibility in the active energy ray-curable resin, the hollow silica fine particles are preferably modified with a silane coupling agent having a polymerizable double bond, if necessary.

(Hollow silica microparticles)
Hollow silica microparticles are microparticles in which silica (silicon dioxide, SiO2) is formed in a substantially spherical shape and has a hollow portion in its outer shell. The hollow silica microparticles have an average particle diameter of 10 to 100 nm, an outer shell thickness of about 1 to 60 nm, and a hollow portion porosity of 40 to 45%. Further, the refractive index of hollow silica fine particles is as low as 1.20 to 1.29. Since the hollow portion contains air with a refractive index of 1.0, the cured film formed by curing the polyfunctional (meth)acrylate can have a low refractive index and a low reflectance. In addition, inorganic fine particles such as silica fine particles can improve the scratch resistance and wear resistance of the cured film. If the porosity of the hollow portion is less than 40%, the amount of air in the hollow portion becomes small, making it difficult to lower the refractive index and reflectance of the cured film.

(Antifouling agent)
From the viewpoint of improving anti-fingerprint property, it is preferable to appropriately add a known polysiloxane-based or fluorine-based antifouling agent to the low refractive index layer. Preferable examples of polysiloxane compounds include polyether-modified polydimethylsiloxane having an acrylic group, polyether-modified dimethylsiloxane, polyester-modified dimethylsiloxane having an acrylic group, polyether-modified polydimethylsiloxane, polyester-modified polydimethylsiloxane, aralkyl-modified polymethylalkylsiloxane, and the like.

The fluorine-based compound used as the antifouling agent preferably has a substituent that contributes to bond formation or compatibility with the low refractive index layer. Such substituents may be the same or different, and may be plural. Examples of preferred substituents include acryloyl group, methacryloyl group, vinyl group, aryl group, cinnamoyl group, epoxy group, oxetanyl group, hydroxyl group, polyoxyalkylene group, carboxyl group and amino group. The fluorine compound may be a polymer or an oligomer with a compound containing no fluorine atom, and the molecular weight is not particularly limited.

<<Third Embodiment>>
FIG. 3 is a longitudinal sectional view of the sheet member 10B of this embodiment. Hereinafter, the sheet material 10B of the present embodiment will be described with a focus on differences from the sheet material 10 of the above-described first embodiment, and the description of the same matters will be omitted as appropriate.
A sheet material 10B of the present embodiment is provided with a low refractive index layer 4 instead of the fine uneven layer 2 of the first embodiment. The low refractive index layer 4 will be mainly described below.

The low refractive index layer 4 is made of a material having a low refractive index and transparency. The refractive index of the low refractive index layer 4 is, for example, 1.0 to 1.5. The upper limit of the refractive index is preferably 1.49 or less, more preferably 1.4 or less.

As the material of the low refractive index layer 4, the material described as the constituent material of the low refractive index layer 32 of the sheet material 10B of the second embodiment can be used.

As described above, according to the present embodiment, reflection of light incident from the low refractive index layer 4 can be reduced, so that the sheet material 10B can achieve a high transmittance. That is, it is possible to improve the efficiency of taking in light from the outside of the device such as LiDAR to the inside of the device through the sheet material 10B.

<<Fourth Embodiment>>
FIG. 4 is a longitudinal sectional view of the sheet material 10C of this embodiment. The sheet material 10C of the present embodiment will be described below, focusing on differences from the sheet material 10 of the above-described first embodiment, and the description of similar matters will be omitted as appropriate.
A sheet material 10C of the present embodiment is provided with a hard coat layer 5 instead of the fine uneven layer 2 of the first embodiment. The hard coat layer 5 will be mainly described below.

<Hard coat layer 5>
The hard coat layer 5 is laminated on the base material layer 1 to cover the base material layer 1 . Thereby, the hard coat layer 5 functions as a coating layer that protects the base material layer 1, and can impart excellent weather resistance, durability, and scratch resistance to the sheet material 10C.

The resin composition used to form the hard coat layer 5 contains silicon-modified (meth)acrylic resin and urethane (meth)acrylate.

By including the silicon-modified (meth)acrylic resin in the resin composition, the surface hardness of the hard coat layer 5 is increased, and excellent scratch resistance can be imparted to the sheet material 10C.

In addition, since the resin composition contains urethane (meth)acrylate, the flexibility of the hard coat layer 5 can be improved, and cracks on the surface of the hard coat layer 5 when the sheet material 10C is thermally bent can be prevented. It is possible to suppress the generation and impart excellent thermoformability to the sheet material 10C.

By combining the silicone-modified (meth)acrylic resin and the urethane (meth)acrylate, it is possible to obtain the sheet material 10C that has both excellent scratch resistance and thermoformability.

(Silicon modified (meth)acrylic resin)
The silicon-modified (meth)acrylic resin has a main chain in which structural units derived from a (meth)acrylic monomer having a (meth)acryloyl group are repeated, and a structural unit linked to the main chain and having a siloxane bond is repeated. It is a polymer (prepolymer) having a repeating body and

By having the main chain, the silicon-modified (meth)acrylic resin imparts transparency to the hard coat layer 5, and by having a repeating body in which the structural unit having the siloxane bond is repeated, the hard It imparts scratch resistance to the coat layer 5 .

Specifically, the main chain of the silicon-modified (meth)acrylic resin is composed of repeating structural units derived from a monomer having a (meth)acryloyl group of at least one of the following formulas (1) and (2): What is done is mentioned.

（式（１）中、ｎは、１以上の整数を示し、Ｒ１は、独立して炭化水素基、有機基、または水素原子を示し、Ｒ０は、独立して炭化水素基または水素原子を示す。）

(In formula (1), n represents an integer of 1 or more, R1 independently represents a hydrocarbon group, an organic group, or a hydrogen atom, and R0 independently represents a hydrocarbon group or a hydrogen atom. .)

（式（２）中、ｍは、１以上の整数を示し、Ｒ２は、独立して炭化水素基、有機基、または水素原子を示し、Ｒ０は、独立して炭化水素基または水素原子を示す。）

(In formula (2), m represents an integer of 1 or more, R2 independently represents a hydrocarbon group, an organic group, or a hydrogen atom, and R0 independently represents a hydrocarbon group or a hydrogen atom. .)

Moreover, it is preferable that the terminal or side chain of the main chain has a hydroxyl group (--OH). That is, in the case of formula (1) or formula (2), R1 or R2 is preferably hydrogen. As a result, when polycarbonate is used as the substrate layer 1, the adhesion between the hard coat layer 5 and polycarbonate can be improved. Therefore, the adhesion of the hard coat layer 5 to the substrate layer 1 is enhanced, and unintentional peeling of the hard coat layer 5 from the substrate layer 1 can be prevented. When a curing agent having an isocyanate group, which will be described later, is used, the hydroxyl group reacts with the isocyanate group of the curing agent to form a crosslinked structure with urethane bonds.

This can accelerate the curing of the resin composition and contribute to the formation of the hard coat layer 5 .

At least one end or side chain of the main chain is bound to a repeating body in which a structural unit having a siloxane bond is repeated.

Since the siloxane bond has a high bonding strength, the silicon-modified (meth)acrylic resin has a repeating body in which structural units having a siloxane bond are repeated, so that the hard coat layer 5 has better heat resistance and weather resistance. can be obtained. In addition, since the hard hard coat layer 5 can be obtained due to the high bonding strength of the siloxane bond, the scratch resistance of the sheet member 10C against impacts such as sand dust and stepping stones can be further increased.

Specific examples of repeating units in which structural units having a siloxane bond are repeated include those composed of repeating structural units having a siloxane bond in at least one of the following formulas (3) and (4). be done.

（式（３）中、Ｘ_１は、炭化水素基または水酸基を示す。）

(In formula (3), X ₁ represents a hydrocarbon group or a hydroxyl group.)

（式（４）中、Ｘ_２は、炭化水素基または水酸基を示し、Ｘ_３は、炭化水素基または水酸基から水素が離脱した２価の基を示す。）

(In formula (4), X2 represents a hydrocarbon group or a hydroxyl group _, and X3 represents a _divalent group in which hydrogen has been removed from the hydrocarbon group or hydroxyl group.)

Specific examples of the repeating body in which the structural unit having the siloxane bond is repeated include those having polyorganosiloxane and those having silsesquioxane. The structure of the silsesquioxane may be any structure such as a random structure, a cage structure, a ladder structure (ladder structure), and the like.

Examples of the hydrocarbon group include alkyl groups such as methyl group, ethyl group, propyl group and isopropyl group; cycloalkyl groups such as cyclopropyl group, cyclobutyl group, cyclopentyl group and cyclohexyl group; -aryl groups such as methylphenyl group, aralkyl groups such as benzyl group, diphenylmethyl group and naphthylmethyl group, phenyl group, biphenyl group and the like.

In addition, it is preferable that an unsaturated double bond is introduced into the terminal or side chain of the repeating unit in which the structural unit having a siloxane bond is repeated. Thereby, it is possible to bond with the (meth)acryloyl group of the urethane (meth)acrylate to form a network of the silicon-modified (meth)acrylic resin and the urethane (meth)acrylate. Therefore, the silicon-modified (meth)acrylic resin and the urethane (meth)acrylate are more uniformly dispersed in the hard coat layer 5, and as a result, the hard coat layer 5 more uniformly exhibits the above-described properties over its entirety. be able to.

The content of the silicon-modified (meth)acrylic resin in the resin composition is not particularly limited, but is preferably 5% by weight or more and 45% by weight or less, and is 9% by weight or more and 28% by weight or less. is more preferable.

If the content of the silicon-modified (meth)acrylic resin in the resin composition is less than the lower limit, the hardness of the hard coat layer 5 obtained from the resin composition may decrease. Further, when the content of the silicon-modified (meth)acrylic resin in the resin composition exceeds the upper limit, the content of materials other than the silicon-modified (meth)acrylic resin in the resin composition is relatively This may reduce the flexibility of the hard coat layer 5 formed using the resin composition.

(Urethane (meth)acrylate)
The urethane (meth)acrylate is a compound having a main chain having a urethane bond (--OCONH--) and a (meth)acryloyl group linked to this main chain. Also, urethane (meth)acrylates are monomers or oligomers.

This urethane (meth)acrylate is a compound having excellent flexibility because it has a urethane bond. Therefore, by including urethane (meth)acrylate in the hard coat layer 5, the hard coat layer 5 can be provided with further flexibility (softness).

Therefore, it is possible to suppress the occurrence of cracks at the bent portion when the sheet material 10C is formed into a curved shape.

Moreover, the number of (meth)acryloyl groups in one molecule of the urethane (meth)acrylate is preferably two or more.

When the number of (meth)acryloyl groups in one molecule of the urethane (meth)acrylate is 2 or more, the urethane (meth)acrylate can bond with the silicon-modified (meth)acrylic resin to form a network. , the curing of the hard coat layer 5 can be accelerated. Thereby, the cross-linking density of the hard coat layer 5 is increased, and the hardness of the hard coat layer 5 can be increased to some extent. Therefore, properties such as scratch resistance and solvent resistance of the hard coat layer 5 can be improved.

The urethane (meth)acrylate can be obtained as a reaction product of an isocyanate compound obtained by reacting a polyol with a diisocyanate and a (meth)acrylate monomer having a hydroxyl group.

Polyols include polyether polyols, polyester polyols and polycarbonate diols.

The polyether polyol is preferably polyethylene oxide, polypropylene oxide, or ethylene oxide-propylene oxide random copolymer having a number average molecular weight of less than 1,300. When a polyether polyol having a number average molecular weight of 1300 or more is used, the flexibility of the hard coat layer 5 is too high, and there is a possibility that the hard coat layer 5 may be easily scratched due to the impact of sand dust, stepping stones, or the like. be.

The polyester polyol can be obtained, for example, by subjecting a diol and a dicarboxylic acid or a dicarboxylic acid chloride to a polycondensation reaction, or by esterifying a diol or a dicarboxylic acid and subjecting it to transesterification. Examples of dicarboxylic acids include adipic acid, succinic acid, glutaric acid, pimelic acid, sebacic acid, azelaic acid, maleic acid, terephthalic acid, isophthalic acid, and phthalic acid. Examples of diols include ethylene glycol, 1,4-butanediol, 1 ,6-hexanediol, diethylene glycol, dipropylene glycol, triethylene glycol, tetraethylene glycol, tripropylene glycol, tetrapropylene glycol and the like are used.

Examples of the polycarbonate diol include 1,4-butanediol, 1,6-hexanediol, ethylene glycol, propylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol and dipropylene glycol. , 2-ethyl-1,3-hexanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanediol, polyoxyethylene glycol and the like are used. More than one species may be used in combination.

Examples of (meth)acrylate monomers having a hydroxyl group include trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol triacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 3- Hydroxybutyl acrylate, polyethylene glycol monoacrylate.

Although the weight average molecular weight of the urethane (meth)acrylate is not particularly limited, it is preferably 1.0×10 ³ or more and 1.5×10 ⁴ or less, and 1.5×10 ³ or more and 1.0×10 ⁴ The following are more preferable. When the weight-average molecular weight of the urethane (meth)acrylate is within the above range, the balance between flexibility and hardness of the hard coat layer 5 is good, and when the sheet material 10C is formed into a curved shape, It is possible to suppress the occurrence of cracks in the bent portion.

The weight average molecular weight of the urethane (meth)acrylate can be measured, for example, by GPC (gel permeation chromatography).

The content of the urethane (meth)acrylate in the resin composition is not particularly limited, but is preferably 10% or more and 75% or less, more preferably 17% or more and 50% or less.

If the content of the urethane (meth)acrylate in the resin composition is less than the lower limit, the flexibility of the hard coat layer 5 may be poor. Further, when the content of the urethane (meth)acrylate in the resin composition exceeds the upper limit, the content of materials other than urethane (meth)acrylate in the resin composition is relatively decreased, and the sheet There is a possibility that the scratch resistance of the material 10C may deteriorate.

The resin composition preferably further contains an acrylate monomer.
Since the resin composition further contains an acrylate monomer, the adhesion between the base material layer 1 and the hard coat layer 5 is improved, and the hard coat layer 5 is less likely to separate from the base material layer 1 during thermal bending. . In addition, since the acrylate monomer also functions as a reactive diluent, it has the function of lowering the viscosity of the resin composition and uniformly dispersing the resin composition in the acrylate monomer.

Examples of the acrylate monomer include, but are not limited to, pentaerythritol tetraacrylate, ditrimethylolpropane triacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol triacrylate, ethoxylated trimethylolpropane triacrylate, ethoxy pentaerythritol triacrylate, ethoxylated pentaerythritol tetraacrylate, polyethylene glycol diacrylate, ethoxylated bisphenol A diacrylate, ethoxylated hydrogenated bisphenol A diacrylate, ethoxylated cyclohexanedimethanol diacrylate, tricyclodecanedimethanol diacrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 3-hydroxybutyl acrylate, isobornyl acrylate and the like.

Among them, from the viewpoint of improving the weather resistance of the sheet material 10C, a resin containing no aromatic group is preferable.

Although the content of the acrylate monomer in the resin composition is not particularly limited, it is preferably 15% or more and 55% or less, and more preferably 27% or more and 55% or less.

If the content of the acrylate monomer in the resin composition is less than the lower limit, the adhesion between the base material layer 1 and the hard coat layer 5 is insufficient, and the hard coat layer 5 separates from the base material layer 1 during thermal bending. easier. Furthermore, the cross-linking density of the hard coat layer 5 may decrease, and the scratch resistance of the sheet material 10C may decrease. Moreover, when the content of the acrylate monomer in the resin composition exceeds the upper limit, the hard coat layer 5 may not be stretched and cracked during thermal bending.

The resin composition preferably further contains isocyanate as a cross-linking agent for intermolecular bonding (cross-linking) of the silicon-modified (meth)acrylate. By using isocyanate as a cross-linking agent, the hydroxyl group of the silicon-modified (meth)acrylate reacts with the isocyanate group of the isocyanate to form a cross-linked structure composed of urethane bonds. Thereby, the scratch resistance of the resin composition can be improved.

Examples of the isocyanate include, but are not limited to, polyisocyanates having two or more isocyanate groups, and more preferably polyfunctional isocyanates having three or more isocyanate groups. This can further improve the scratch resistance.

Although the content of the isocyanate in the resin composition is not particularly limited, it is preferably 3% or more and 40% or less, and more preferably 6% or more and 25% or less.

If the content of the isocyanate in the resin composition is less than the lower limit, the scratch resistance of the hard coat layer 5 may deteriorate. In addition, when the content of the isocyanate in the resin composition exceeds the upper limit, the unreacted isocyanate remains in the coating film as an impurity, so that the scratch resistance and durability of the coating film (adhesion of the coating film ) may decrease.

Moreover, the resin composition may contain an ultraviolet absorber. The ultraviolet absorber is not particularly limited, but includes triazine-based, benzophenone-based, benzotriazole-based, and cyanoacrylate-based ultraviolet absorbers, and one or two of these may be used in combination. Among these, triazine-based ultraviolet absorbers are particularly preferably used, and among triazine-based ultraviolet absorbers, hydroxyphenyltriazine-based ultraviolet absorbers are more preferable. As a result, deterioration of the hard coat layer 5 due to ultraviolet rays can be more reliably prevented or suppressed, and the weather resistance of the sheet material 10C can be further increased.

Further, the content of the ultraviolet absorber in the resin composition is not particularly limited, but is preferably 1.0 wt% or more and 5.0 wt% or less, and 1.5 wt% with respect to 100 wt% of the main resin. It is more preferable that the content is 4.0 wt % or more. If the content of the ultraviolet absorber in the resin composition is less than the lower limit, the weather resistance of the hard coat layer 5 may deteriorate. Further, even if the content of the ultraviolet absorber in the resin composition exceeds the upper limit, no further improvement in weather resistance is observed, and the transparency of the hard coat layer 5 and the Adhesion to the base material layer 1 may be impaired.

Moreover, the resin composition may contain a photopolymerization initiator. Examples of the photopolymerization initiator include, but are not limited to, benzoin or benzoin alkyl ethers such as benzoin, benzoin methyl ether, benzoin ethyl ether, and benzoin isopropyl ether; aromatic ketones such as benzophenone and benzoylbenzoic acid; alpha-dicarbonyls, benzyl ketals such as benzyl dimethyl ketal, benzyl diethyl ketal, acetophenone, 1-(4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methyl-propan-1-one, 2-methyl-1-[ 4-(methylthio)phenyl]-2-morpholinopropanone-1 and other acetophenones, 2-methylanthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone and other anthraquinones, 2,4-dimethylthioxanthone, 2- thioxanthones such as isopropylthioxanthone and 2,4-diisopropylthioxanthone; phosphine oxides such as bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide; 1-phenyl-1,2-propanedione-2- Alpha-acyl oximes such as (o-ethoxycarbonyl) oxime, amines such as ethyl p-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, and the like can be used. 4-dodecylphenyl)-2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexylphenyl ketone, 2-hydroxy-2-methyl-1-phenyl-1-propan-1-one, 1-(4 -isopropylphenyl)-2-hydroxy-2-methyl-propan-1-one, 2-methyl-1-[4-(methylthio)phenyl]-2-morpholinopropanone-1 and other acetophenones are preferred. .

The content of the photopolymerization initiator in the resin composition is not particularly limited, but is preferably 0.5 wt % or more and 10 wt % or less, and 2.0 wt % or more, relative to 100 wt % of the main resin. It is more preferably 6.0 wt% or less. If the content of the photopolymerization initiator in the resin composition is less than the lower limit, it may be difficult to sufficiently cure the resin composition. Even if the initiator content exceeds the upper limit, no further improvement is observed.

The resin composition may contain materials other than the materials described above.
Other materials include, for example, resin materials other than the silicon-modified (meth)acrylic resin, colorants, sensitizers, stabilizers, surfactants, antioxidants, reduction inhibitors, antistatic agents, and surface conditioners. and solvents.

Examples of solvents include aliphatic hydrocarbons such as hexane, heptane and cyclohexane; aromatic hydrocarbons such as toluene and xylene; alcohols such as methanol, ethanol, propanol and butanol; ketones, esters such as ethyl acetate, butyl acetate, isobutyl acetate and methoxypropyl acetate, cellosolve solvents such as ethyl cellosolve, glycol solvents such as methoxypropanol, ethoxypropanol and methoxybutanol. These can be used alone or in combination. Among these, alcohol-based, cellosolve-based, and glycol-based solvents may react with the isocyanate in the resin composition, so it is desirable not to use them alone. It is more preferable to use a hydrocarbon-based, ketone-based, or ester-based solvent as the main component of the solvent.

Although the thickness of the hard coat layer 5 is not particularly limited, it is preferably 1 μm or more and 40 μm or less, more preferably 2 μm or more and 30 μm or less, and even more preferably 3 μm or more and 20 μm or less. If the thickness of the hard coat layer 5 is less than the lower limit, the weather resistance of the sheet material 10C may deteriorate. On the other hand, if the thickness of the hard coat layer 5 exceeds the upper limit, cracks may occur at the bent portion when the sheet material 10C is formed into a curved shape.

As described above, according to the present embodiment, since the hard coat layer 5 protects the surface of the base material layer 1, the scratch resistance and durability of the sheet material 10C can be maintained for a long period of time. That is, the efficiency of taking in light from the outside of the device such as LiDAR to the inside of the device via the sheet material 10C can be maintained high for a long period of time.

<<Fifth Embodiment>>
FIG. 5 is a longitudinal sectional view of the sheet material 10D of this embodiment. Hereinafter, the sheet material 10D of the present embodiment will be described with a focus on the differences from the sheet material 10 of the above-described first embodiment, and the description of the same matters will be omitted as appropriate.
In the sheet material 10 of the first embodiment, the fine uneven layer 2 is provided only on one side (upper side surface) of the base layer 1, but in the sheet material 10D of the present embodiment, the fine uneven layer 2a is provided on both sides of the base layer 1. , 2b.
With this configuration, the fine uneven layer 2b on the surface facing the sensor light emitting/receiving part 9 inside the device allows the laser light to pass through efficiently without being reflected, and also causes fogging due to dirt and water droplets. can be accurately suppressed and prevented.

<<Sixth Embodiment>>
FIG. 6 is a longitudinal sectional view of the sheet material 10E of this embodiment. Hereinafter, the sheet material 10E of the present embodiment will be described with a focus on the differences from the sheet material 10A of the above-described second embodiment, and the description of the same matters will be omitted as appropriate.
In the sheet material 10A of the second embodiment, the low-reflection layer 3 is provided only on one side (upper side surface) of the base material layer 1, but in the sheet material 10E of the present embodiment, the low-reflection layers 3a are provided on both sides of the base material layer 1. , 3b.
With this configuration, the low-reflection layer 3b on the surface facing the sensor light emitting/receiving section 9 inside the device allows the laser light to pass through efficiently without being reflected, and also causes fogging due to dirt or water droplets. can be accurately suppressed and prevented.

<<Seventh embodiment>>
7(a) to 7(d) show the seventh embodiment and other four embodiments.
Hereinafter, the sheet materials 10F to 10I of the present embodiment are provided on the lower surface of the base material layer 1 in addition to the sheet material 10C of the fifth embodiment (having the base material layer 1 and the hard coat layer 5). The functional layers (fine unevenness layer 2c, low reflection layer 3c, low refractive index layer 4a, hard coat layer 5b) of the first to fifth embodiments are provided. The following description will focus on the points of difference, and the description of the same items will be omitted as appropriate.

The sheet material 10F shown in FIG. 7A includes a base layer 1, a hard coat layer 5 provided on the upper side of the base layer 1, and a fine uneven layer 2c provided on the lower side of the base layer 1. have The fine concavo-convex layer 2c of this embodiment is the same as the fine concavo-convex layer 2 of the first embodiment. In addition, it can be said that the hard coat layer 5 replaces the fine uneven layer 2a on the upper side of the sheet material 10D in FIG.
According to the sheet member 10F having this configuration, the scratch resistance and durability can be maintained for a long period of time due to the hard coat layer 5 exposed to the outside. In addition, the fine irregularity layer 2c exposed to the inside of the device (sensor light emitting/receiving part 9) allows the laser beam to pass through the inside of the device efficiently without being reflected, and also accurately suppresses fogging due to dirt and water droplets.・Can be prevented.

The sheet material 10G shown in FIG. 7B includes a base layer 1, a hard coat layer 5 provided on the upper side of the base layer 1, and a low reflection layer 3c provided on the lower side of the base layer 1. have The low-reflection layer 3c of this embodiment is the same as the low-reflection layer 3 of the second embodiment.
According to the sheet member 10G having this configuration, the scratch resistance and durability can be maintained for a long period of time due to the hard coat layer 5 exposed to the outside. In addition, the low-reflection layer 3c exposed to the inside of the device (sensor light emitting/receiving portion 9) allows efficient transmission of the laser beam without reflection in the inside of the device.

A sheet material 10H shown in FIG. 7C includes a base layer 1, a hard coat layer 5 provided on the upper side of the base layer 1, and a low refractive index layer 4a provided on the lower side of the base layer 1. and The low refractive index layer 4a of this embodiment is the same as the low refractive index layer 4 of the third embodiment.
According to the sheet material 10H having this configuration, the scratch resistance and durability can be maintained for a long period of time due to the hard coat layer 5 exposed to the outside. In addition, the low refractive index layer 4a exposed to the inside of the device (sensor light emitting/receiving portion 9) allows the laser beam to be efficiently transmitted through the inside of the device without being reflected.

A sheet material 10I shown in FIG. have The hard coat layers 5a and 5b of this embodiment are the same as the hard coat layer 5 of the fourth embodiment.
According to the sheet material 10I having this configuration, the scratch resistance and durability can be maintained for a long period of time due to the hard coat layer 5 exposed to the outside. In addition, the hard coat layer 5b exposed to the inside of the device (sensor light emitting/receiving portion 9) can effectively prevent damage caused by foreign matter or the like entering the inside of the device.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than those described above can be adopted. Moreover, the present invention is not limited to the above-described embodiments, and includes modifications, improvements, etc. within the scope of achieving the object of the present invention.

EXAMPLES The present invention will now be described more specifically based on examples.
1. Preparation of sheet material [Example 1]
First, 99.62 wt% bisphenol A type polycarbonate (Mitsubishi Engineering Plastics, "H3000") and 0.03 wt% first light absorber (quinoline; Arimoto Chemical Industry Co., Ltd., "platyellow8050") , 0.05 wt% second light absorber 1 (anthraquinone A; manufactured by Arimoto Chemical Industry Co., Ltd., "Plast blue 8590") and 0.05 wt% second light absorber 2 (anthraquinone B; Arimoto Chemical Industry company, "SDO-7"), 0.07 wt% third light absorber (perinone; Arimoto Chemical Industry Co., Ltd., "Plast red 8370"), and 0.18 wt% ultraviolet absorber (UVA; "LA-31G" manufactured by ADEKA Corporation) was stirred and mixed to prepare a first layer forming material.

Then, the material for forming the first layer was placed in an extruder, melted, co-extruded from a T-die, and cooled to obtain a sheet material composed of the first layer (base material layer 1).

Next, a sheet material was obtained by attaching a fine uneven layer (moth-eye layer) manufactured as described below to one surface of the sheet material composed of the first layer via an adhesive layer. . Then, the obtained sheet material was cut into a rectangular shape having a thickness of 2.0 mm and a size of 100 mm×100 mm in plan view to prepare an optical laminate.
A fine uneven layer (moth-eye layer) was produced as follows.

First, a cylindrical aluminum base material (outer diameter: 200 mm, inner diameter: 155 mm, length: 350 mm) was prepared. By repeating the pore size enlarging treatment step, conical pores having an average pitch of 200 nm and an average depth of 200 nm, that is, a roll-shaped reverse transfer having an anodized alumina having an inverted moth-eye structure on the surface prepared the mold.
The thickness of the first layer in the obtained optical laminate was 2.0 mm.

Next, a fluorine-based release agent ("UD-509" manufactured by Daikin Industries, Ltd.) is applied to the prepared reversal transfer mold for release treatment, and then the roll-shaped reversal transfer mold is rotated. At the same time, a triacetyl cellulose substrate (“TD80ULM” manufactured by Fuji Film Co., Ltd., thickness 80 μm) was run along the outer peripheral surface of the reversal transfer mold in the direction of rotation of the reversal transfer mold. At this time, an ultraviolet curable resin ("KCC-UV-HG" manufactured by Koshin Chemical Co., Ltd.) is supplied between the outer peripheral surface of the reverse transfer mold and the triacetyl cellulose base material, and then the ultraviolet curable resin is exposed to the ultraviolet ray. to obtain a moth-eye layer (moth-eye anti-reflection layer) in which a moth-eye structure was transferred to the cured product of the ultraviolet curable resin.

[Example 2]
An optical layered body of Example 2 was obtained in the same manner as in Example 1 except that the structure of the optical layered body was changed as shown in Table 1. The hard coat layer in Example 2 is the third layer 3 (protective layer) described above, and the structure is as shown in Table 1.

2% by mass of hydrophobic silica ("Reolosil HM20S" manufactured by Tokuyama Co., Ltd., particle size: about 12 nm) was added to 98% by mass of isopropyl alcohol and dispersed using an ultrasonic disperser to obtain a hydrophobic silica dispersion. .
The resulting hydrophobic silica dispersion was applied onto the prepared resin sheet material (base material layer 1) by a flow coating method and dried at room temperature to form a nanoparticle laminated coating.

[Example 3]
An optical layered body of Example 3 was obtained in the same manner as in Example 1 except that the structure of the optical layered body was changed as shown in Table 1. The low reflection layer (multilayer interference structure) was manufactured as follows.

70 parts by mass of zinc antimonate fine particle dispersion (manufactured by Nissan Chemical Industries, Ltd., "Celnax CX-603M-F2" in terms of solid content), urethane acrylate (molecular weight: 1400, manufactured by Mitsubishi Chemical Corporation, "Shiko UV7600B" ”) 25 parts by mass, 5 parts by mass of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals Co., Ltd., “Irgacure 184”), and 500 parts by mass of isopropyl alcohol were mixed to form a composition for forming a high refractive index layer ( A curable coating liquid containing fine particles of zinc antimonate) was obtained.

50 parts by mass of hollow silica fine particles having a particle diameter of 60 nm, OD2H2A (1,10-diacryloyloxy-2,9-dihydroxy-4,4,5,5,6,6,7,7,-octafluorodecane) 50 Parts by mass, photopolymerization initiator (manufactured by Ciba Specialty Chemicals Co., Ltd., "Irgacure 907") 5 parts by mass, leveling material (manufactured by BYK Chemie Japan Co., Ltd., "BYKUV-3570") 8 parts by mass, leveling material (manufactured by Shin-Etsu Chemical Co., Ltd., "TIC2457") 5 parts by mass, scratch-resistant alumina additive (manufactured by BYK-Chemie Japan Co., Ltd., "NANOBYKUV-3601") 0.5 parts by mass, and isopropyl alcohol 2000 parts by mass were mixed to obtain a low refractive index layer composition (silica-containing curable coating liquid).

A composition for forming a hard coat layer (“Lio Duras LAS1303NL” manufactured by Toyo Ink Mfg. Co., Ltd.) was applied on a transparent base film made of triacetyl cellulose (TAC) film having a thickness of 80 μm with a roll coater to obtain a dry film thickness. It was applied to a thickness of 4.0 μm and dried at 80° C. for 2 minutes. After that, the composition for forming a hard coat layer was cured by irradiating with ultraviolet rays from an ultraviolet irradiation device (120 W high-pressure mercury lamp manufactured by Ushio Inc.) in a nitrogen atmosphere (accumulated light amount: 350 mJ/cm ² ) to form a hard coat layer. .

Next, the composition for forming a high refractive index layer was applied onto the hard coat layer so that the thickness when dry was 150 nm, and then under a nitrogen atmosphere, an ultraviolet irradiation apparatus (120 W high pressure mercury lamp manufactured by Ushio Inc.) was applied. was used to irradiate ultraviolet rays of 350 mJ/cm ² to cure the composition for forming a high refractive index layer, thereby forming a high refractive index layer.

Finally, the composition for the low refractive index layer was applied onto the high refractive index layer so that the dry thickness was 100 nm, and then the composition was applied with an ultraviolet irradiation device (120 W high-pressure mercury lamp manufactured by Ushio Inc.) under a nitrogen atmosphere. ) was used to irradiate ultraviolet rays of 350 mJ/cm ² to cure the low refractive index layer composition to form a low refractive index layer, thereby producing a film.

[Example 4]
An optical layered body of Example 4 was obtained in the same manner as in Example 1 except that the structure of the optical layered body was changed as shown in Table 1.

[Comparative Example 1]
An optical layered body of Comparative Example 1 was obtained in the same manner as in Example 1 except that the structure of the optical layered body was changed as shown in Table 1.

2. Evaluation of Sheet Material The sheet materials of Examples 1 to 4 and Comparative Example 1 were evaluated by the following method. The contact angle was not evaluated in Example 4.

(contact angle)
Using a contact angle meter (DMo-702: manufactured by Kyowa Interface Science Co., Ltd.), 1.0 μl of pure water was dropped on the sheet sample to measure the contact angle, and evaluation was performed as follows.
A: 130° or more B: 90° or more and less than 130° C: less than 90°

(sliding angle)
After dropping 10 μl of pure water onto the sheet sample using a contact angle meter (DMo-702: manufactured by Kyowa Interface Science Co., Ltd.), the stage was tilted to measure the sliding angle, and evaluation was performed as follows.
A: Less than 5° B: 5° or more and less than 30° C: 30° or more

(Transmittance)
Spectral transmittance meter (V-670: JASCO, variable angle film holder unit) prepares a separate sheet material of 0.5 mmt so as not to be affected by the thickness, and near infrared light at wavelengths of 905 nm and 1550 nm Average transmittance was measured. At each wavelength, the incident angles of 0° and 60° were measured, the transmittance at an incident angle of 0° was T1, the transmittance at an incident angle of 60° was T2, and T2/T1 was calculated for evaluation. .

(Anti-fouling)
The sheet materials of Examples 1 to 4 and Comparative Example 1 were attached to the front bumper of the vehicle so that the sheet was at an angle of 90°. was evaluated in this way.
A: Adhesion of dust is hardly observed B: Adhesion of dust is observed, but the extent is slight C: Large trace of adhesion of dust is observed

(Evaluation results)
Table 1 below shows the measurement results and evaluation results for the sheet materials of Examples 1 to 4 and Comparative Example 1 obtained as described above.

(Evaluation of contact angle)
For Examples 1 and 2, the contact angle value (evaluation A) was very favorable. The results of Example 3 were also sufficiently satisfactory (Evaluation B).

(Evaluation of sliding angle)
For Examples 1 and 2, the contact angle value (evaluation A) was very favorable. The results of Examples 3 and 4 were also sufficiently satisfactory (Evaluation B).

(Evaluation of transmittance T2/T1)
All of the sheet materials of Examples 1 to 4 exhibited satisfactory values in the range of 0.8≦T2/T1≦1.2.

(Evaluation of antifouling property)
In Examples 1 to 4, high antifouling properties were exhibited and satisfactory results were obtained. In particular, in Examples 1 and 2, almost no adhering dust was observed even after long-term use. In addition, in Example 3, the adhering dust was very small, and it is considered to be sufficiently satisfactory for practical use.

(Evaluation of wide-range sensing function)
Although not shown in the table, the sensing function at an angle (0° to 60°) was evaluated for reduction in sensing distance when attached to LiDAR. At this time, it was confirmed that in Examples 1 to 4, the reduction in sensing distance was small and a wide range could be sensed. In particular, in Examples 1 and 3, compared with Examples 2 and 4 and Comparative Example 1, the decrease in sensing distance was extremely small. This is probably because the transmittance T1 at an incident angle of 0° and the transmittance T2 at an incident angle of 60° at wavelengths of 905 nm and 1550 nm are higher than those of Examples 2 and 4 and Comparative Example 1.

(Comprehensive evaluation)
From the viewpoint of antifouling property and sensing distance, the sheet materials of Examples 1 and 3 were particularly highly satisfactory.

1 base material layer 2, 2a ~ 2c fine uneven layer 3, 3a ~ 3c low reflection layer 4, 4a low refractive index layer 5, 5a, 5b hard coat layer 9 sensor light receiving and emitting part 10, 10A ~ 10I sheet material 31 high refraction Index layer 32 Low refractive index layer

Claims (15)

A resin sheet material that transmits near-infrared rays,
A sheet material body including a resin material as a main material having translucency and a visible light transmission suppressing material for suppressing the transmission of visible light through the resin material,
When the transmittance is T1 (%) when the incident angle of the near-infrared rays with respect to the surface of the sheet material body is 0 degrees, and the transmittance is T2 (%) when the incident angle is 60 degrees, conditions (1) to (3) ), the sheet material.
(1) T1>87.5%
(2) T2>79.0%
(3) 0.8≤T2/T1≤1.2 2. The sheet material according to claim 1, which satisfies the conditions (1) to (3) in near infrared rays with a wavelength of 905 nm. At an infrared wavelength of 905 nm, the transmittance T1 (%) is 91% or more,
The sheet material according to claim 1 or 2. At an infrared wavelength of 905 nm, the transmittance T2 (%) is 80% or more,
The sheet material according to any one of claims 1 to 3. 5. The sheet material according to any one of claims 1 to 4, which satisfies the conditions (1) to (3) in near infrared rays having a wavelength of 1550 nm. The sheet material according to any one of claims 1 to 5, wherein the transmittance T1 (%) is 91% or more in near-infrared rays having a wavelength of 1550 nm. 7. The sheet material according to any one of claims 1 to 6, wherein the transmittance T2 (%) is 81% or more in near-infrared rays having a wavelength of 1550 nm. 8. The sheet material according to any one of claims 1 to 7, wherein the visible light transmission suppressing material is a visible light absorbent that is dispersed in the resin material and that absorbs visible light. 9. The sheet material according to any one of claims 1 to 8, wherein the surface of the sheet material main body is provided with a fine uneven structure having periodic unevenness. 10. The sheet material according to claim 9, wherein the unevenness period of the fine uneven structure is 800 nm or less. The height of the protrusions of the fine uneven structure is 100 to 400 nm,
The sheet material according to claim 9 or 10. The surface of the sheet material body comprises a laminated structure having at least one high refractive index layer and at least one low refractive index layer,
Sheet material according to any one of claims 1 to 11. The contact angle of the droplet on the surface of the sheet material body is 90° or more and less than 180°.
Sheet material according to any one of claims 1 to 12. The sliding angle of the droplet on the surface of the sheet material body is 1° or more and less than 30°.
Sheet material according to any one of claims 1 to 13. In a remote sensing type measuring device that irradiates an object with near-infrared laser light and measures the distance by capturing the reflected light with an optical sensor, it is used in the window through which the irradiated light or reflected light of the laser light passes 15. A sheet material according to any one of claims 1 to 14, wherein the sheet material is

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