JP6979994B2 - Optical body and window material - Google Patents

Description

The present invention relates to an optical body and a window material, and more specifically, to an optical body having both high antiglare property and viewability, and a window material provided with the same.

In recent years, in buildings including high-rise buildings and tower apartments, so-called reflected light damage, which causes light to be reflected on the window glass etc. to be mounted and causes glare to users of other neighboring buildings, is often a problem. It has become. Therefore, when constructing a building, it is required to take sufficient measures against the above-mentioned reflected light pollution.

Here, as a measure against the glare of the reflected light from the window glass of the building, for example, a method of installing a louver or the like on the wall surface of the building to directly block the reflected light can be mentioned. However, the installation of louvers is often shunned by owners because the construction work is large and costly, and it also affects the design of the building.

On the other hand, as a method for improving the antiglare property of the window glass of a building, in addition to the above-mentioned method, a method of attaching a film to the window glass to improve the reflection characteristics can be mentioned.

For example, as a film capable of improving reflective properties including antiglare, Patent Document 1 uses an ultraviolet curable resin to form an AG (anti-glare) layer having a random uneven shape surface on a base film, and the unevenness thereof. By forming a layer made of a low refractive index resin so as to flatten the shape, an optical film capable of making black stand out when attached to a display while flattening the reflectance in the visible light region is obtained. It is disclosed that it will be done.

Further, Patent Document 2 uses a mold surface on which blast particles having a predetermined particle size are struck when the unevenness of the mold surface is transfer-molded on a base film using an ultraviolet curable resin to obtain a film. As a result, it is disclosed that a film with reduced glare can be obtained while maintaining high transmission sharpness.

International Publication 2015/071943 Japanese Unexamined Patent Publication No. 2016-012095

However, all of the above-mentioned conventional films are mainly used for polarizing plates provided on the display surface of a liquid crystal panel of a personal computer, a liquid crystal television, or the like. All of the above-mentioned conventional films have room for improvement from the viewpoint of achieving both high anti-glare property and viewability when used for window glass.

An object of the present invention is to solve the above-mentioned problems in the prior art and to achieve the following objects. That is, an object of the present invention is to provide an optical body having excellent anti-glare property and viewability, and a window material having excellent anti-glare property and view property.

The present inventors have conducted diligent studies without limiting to films in order to achieve the above object. As a result, it has been found that both high anti-glare property and viewability can be achieved by optimizing the roughness characteristic of the fine uneven surface, and the present invention has been completed.

The present invention is based on the above-mentioned findings by the present inventors, and the means for solving the above-mentioned problems are as follows. That is,
<1> An optical body provided with a fine concavo-convex layer.
In a rectangular area of 35.3 μm × 26.5 μm on the surface of fine irregularities,
Arithmetic mean roughness Ra is 0.2 μm or less, and
The average length RSm of the roughness curve element is 10 μm or less, or the ratio of the surface area to the area of the rectangle is 1.04 or more and 1.5 or less.
It is an optical body characterized by this.

<2> Further provided with a first transparent inorganic layer and a second transparent inorganic layer,
The optical body according to <1>, wherein the first transparent inorganic layer is arranged on the fine uneven surface of the fine uneven layer, and the second transparent inorganic layer is arranged on the first transparent inorganic layer. be.

<3> The first transparent inorganic layer contains at least one of _{ZnO and CeO 2, and the first transparent inorganic layer contains at least one of ZnO and CeO 2.}
The optical body according to <2>, wherein the second transparent inorganic layer _{contains at least one of SiO 2} , SiN, SiON and MgF _2.

<4> The total haze is 15% or more and 60% or less, the internal haze is 4% or less, the glossiness at a measurement angle of 20 ° is 40 or less, and the transmission image sharpness at an optical comb width of 2 mm is 50. % Or more, the optical body according to any one of <1> to <3>.

<5> The optical body according to any one of <2> to <4>, further comprising a third transparent inorganic layer on the second transparent inorganic layer.

<6> A window material comprising a glass substrate and the optical body according to any one of <1> to <5>.

INDUSTRIAL APPLICABILITY According to the present invention, there is provided an optical body which can solve the above-mentioned problems in the prior art and can achieve the above object and has excellent anti-glare property and viewability, and a window material having excellent anti-glare property and view property. be able to.

It is a schematic cross-sectional view which shows the structural example of the optical body which concerns on one Embodiment of this invention. It is a schematic diagram which shows an example method for forming the fine concavo-convex layer of the optical body which concerns on one Embodiment of this invention. It is a schematic cross-sectional view which shows the structural example of the optical body which concerns on one Embodiment of this invention. It is a schematic cross-sectional view which shows the structural example of the optical body which concerns on one Embodiment of this invention. It is a schematic cross-sectional view which shows the structural example of the optical body which concerns on one Embodiment of this invention. It is a schematic sectional drawing which shows the structural example of the window material which concerns on one Embodiment of this invention. It is a schematic sectional drawing which shows the structural example of the window material which concerns on one Embodiment of this invention. It is a schematic sectional drawing which shows the structural example of the window material which concerns on one Embodiment of this invention.

(Optical body)
As shown in FIG. 1, the optical body (hereinafter, may be referred to as “optical body according to the present embodiment”) 60 according to an embodiment of the present invention includes at least a fine concavo-convex layer 63. Further, the optical body according to the present embodiment may further include a first transparent inorganic layer, a second transparent inorganic layer, a third transparent inorganic layer, an antifouling coat layer, and other layers, if necessary.

<Fine uneven layer>
The fine concavo-convex layer is a layer having a fine concavo-convex structure on at least one surface. This uneven structure may be formed in a regular pattern or may be randomly formed.

The fine uneven surface of the fine uneven layer has an arithmetic average roughness Ra of 0.2 μm or less in a rectangular region of 35.3 μm × 26.5 μm. Further, in the fine uneven surface of the fine uneven layer, the average length RSm of the roughness curve element is 10 μm or less in the rectangular region, or the area of the rectangular (that is, 35.3 μm × 26.5 μm = 935). The ratio of the surface area (μm ^{2 ) to the .45 μm 2} ) (hereinafter, may be referred to as “specific surface area”) is 1.04 or more and 1.5 or less. Surprisingly, the present inventors set the arithmetic average roughness Ra of the fine uneven surface to 0.2 μm or less, while keeping the average length RSm and / or the specific surface area of the roughness curve element within the above-mentioned range. As a result, unevenness with a shape smaller than the wavelength of the visible light region can be formed, and a part of the light can be transmitted without changing the traveling direction to improve the clarity of the transmitted image. It was found that an optical body compatible with the above can be obtained.

Further, from the viewpoint of further enhancing the antiglare property and the viewability, the fine uneven surface of the fine uneven layer has an average length RSm of the roughness curve element of 10 μm or less and a specific surface area of 1.04 or more and 1.5. The following is preferable.

The arithmetic average roughness Ra of the fine uneven surface in the fine uneven layer is preferably 0.18 μm or less, and more preferably 0.14 μm or less, from the viewpoint of achieving both higher anti-glare property and viewability. preferable. On the other hand, the arithmetic average roughness Ra of the fine uneven surface in the fine uneven layer is preferably 0.08 μm or more, and more preferably 0.09 μm or more from the viewpoint of further enhancing the antiglare property.

Further, the average length RSm of the roughness curve element of the fine uneven surface in the fine uneven layer is preferably 6 μm or less from the viewpoint of further enhancing the transparency of the transmitted image. Further, the average length RSm of the roughness curve element of the surface of the fine unevenness in the fine unevenness layer is 2 μm or more from the viewpoint of achieving both higher anti-glare property and viewability and increasing the physical strength of the fine unevenness. It is preferable to have.

Further, the specific surface area of the fine uneven surface in the fine uneven layer is preferably 1.1 or more from the viewpoint of further enhancing the antiglare property. Further, the specific surface area of the fine uneven surface in the fine uneven layer is preferably 1.4 or less from the viewpoint of further enhancing the viewability.

The Ra, RSm and specific surface area described above can be measured by the method used in the examples.

Here, the fine concavo-convex layer can be formed by, for example, a shape transfer method, a phase separation method, a filler dispersion method, or the like. Hereinafter, as an example, a method of forming a fine concavo-convex layer by a shape transfer method will be described with reference to FIG.

FIG. 2 is a schematic diagram showing a shape transfer method, which is an example of a method for forming a fine concavo-convex layer of an optical body according to the present embodiment. The shape transfer device 1 shown in FIG. 2 includes a master 2, a base material supply roll 51, a take-up roll 52, guide rolls 53 and 54, a nip roll 55, a peeling roll 56, a coating device 57, and a light source. It is equipped with 58.

The base material supply roll 51 is a roll in which a sheet-shaped base material 61 is wound into a roll shape, and the take-up roll 52 winds up the base material 61 on which the resin layer 62 to which the fine concavo-convex structure 23 is transferred is laminated. It is a roll. Further, the guide rolls 53 and 54 are rolls for conveying the base material 61. The nip roll 55 is a roll in which the base material 61 on which the resin layer 62 is laminated is brought into close contact with the cylindrical master 2, and the peeling roll 56 is a resin layer after the fine concavo-convex structure 23 is transferred to the resin layer 62. This is a roll for peeling the base material 61 on which the 62 is laminated from the master 2. Here, the base material 61 can be a base material made of plastic such as PET resin or polycarbonate resin, or can be a transparent film made of plastic.

The coating device 57 is provided with a coating means such as a coater, and a composition containing an ultraviolet curable resin (ultraviolet curable resin composition) is applied to the base material 61 to form a resin layer 62. The coating device 57 may be, for example, a gravure coater, a wire bar coater, a die coater, or the like. Further, the light source 58 is a light source that emits ultraviolet light, and may be, for example, an ultraviolet lamp or the like.

The ultraviolet curable resin is a resin whose fluidity is lowered and cured by being irradiated with ultraviolet rays, and specific examples thereof include acrylic resins. Further, the ultraviolet curable resin composition may contain an initiator, a filler, a functional additive, a solvent, an inorganic material, a pigment, an antistatic agent, a sensitizing dye and the like, if necessary.

In the shape transfer device 1, first, the sheet-shaped base material 61 is continuously delivered from the base material supply roll 51 via the guide roll 53. The ultraviolet curable resin composition is applied to the delivered base material 61 by the coating device 57, and the resin layer 62 is laminated on the base material 61. Further, the base material 61 on which the resin layer 62 is laminated is brought into close contact with the master 2 by the nip roll 55. As a result, the fine uneven structure 23 formed on the outer peripheral surface of the master 2 is transferred to the resin layer 62. After the fine concavo-convex structure 23 is transferred, the resin layer 62 is cured by irradiation with light from the light source 58. Subsequently, the base material 61 on which the cured resin layer 62 is laminated is peeled from the master 2 by the peeling roll 56, and is taken up by the take-up roll 52 via the guide roll 54.
With such a shape transfer device 1, it is possible to continuously form a fine concavo-convex layer having a fine concavo-convex surface. Here, Ra, RSm and the specific surface area of the fine uneven surface can be adjusted, for example, by appropriately changing the fine uneven structure 23 of the master 2.

In the above-mentioned shape transfer method, a base material and an ultraviolet curable resin are prepared, and a fine unevenness layer is formed on the base material using the resin (that is, as shown in FIG. 1, fine unevenness). The layer 63 is composed of a base material 61 and a resin layer 62 having a fine concavo-convex structure), but the fine concavo-convex layer of the optical body of the present invention is not limited to this, and is, for example, an ultraviolet curable resin or a thermosetting resin. The fine concavo-convex structure may be directly formed on a base material made of a resin such as the above (that is, the fine concavo-convex layer 63 is made of only the base material 61 as shown in FIG. 3).

<First transparent inorganic layer>
Further, as shown in FIG. 4, it is preferable that the optical body 60 according to the present embodiment is provided with the first transparent inorganic layer 64 on the fine uneven surface of the fine uneven layer 63. The first transparent inorganic layer 64 can have transparency and, for example, a function of absorbing light having a predetermined wavelength. Further, the first transparent inorganic layer 64 can be formed by, for example, a sputtering method or a CVD method.
In addition, in this specification, "transparent" or "having transparency" means that the transmission image sharpness is high and the image can be clearly seen through an optical body.

The main component of the first transparent inorganic layer is preferably an inorganic compound having a bandgap of 2.8 eV or more and 4.8 eV or less. Here, the bandgap represents the wavelength of the absorption edge, and in a broad sense, it indicates that it absorbs light below the wavelength corresponding to the bandgap and transmits light above the wavelength corresponding to the bandgap. The band gap of 2.8 eV or more and 4.8 eV or less described above can be obtained by using ^{Planck's constant (6.626 × 10 -34} J · s) and the speed of light (2.998 × 10 ^{8 m / s).} Relational expression between wavelength λ and band gap energy E: From "λ (nm) = 1240 / E (eV)", the absorption edge is approximately within the range of 260 nm or more and 440 nm or less, which is the boundary between the ultraviolet region and the visible region. It shows that there is a wavelength. Therefore, by using the above-mentioned inorganic compound for the first transparent inorganic layer, both transparency and ultraviolet absorption characteristics can be achieved. From the same viewpoint, the main component of the first transparent inorganic layer is more preferably an inorganic compound having a bandgap of 3.0 eV or more and 3.7 eV or less (about 340 nm or more and 420 nm or less in terms of wavelength). In addition, the main component of the first transparent inorganic layer is 3.0 eV or more and 3.4 eV or less (about 360 nm or more in terms of wavelength), considering that thinning is planned to suppress the risk of productivity decrease and crack generation. It is more preferable that the inorganic compound has a bandgap of 420 nm or less).
In the present specification, the "main component" refers to the component having the highest content.

Specific examples of the inorganic compound having a bandgap of 2.8 eV or more and 4.8 eV or less include ZnO, CeO ₂ , TiO ₂ , SnO ₂ , In ₂ O ₃ , Nb ₂ O ₅ , and Ta ₂ O ₅ . Examples include SiC and ZnS. Specific examples of the inorganic compound having a bandgap of 3.0 eV or more and 3.7 eV or less include ZnO, CeO ₂ , TiO ₂ , Nb ₂ O ₅ , SiC, ZnS and the like. Further, examples of the inorganic compound having a band gap of 3.0 eV or more and 3.4 eV or less include ZnO, CeO _{2 and the} like. In consideration of the above, the first transparent inorganic layer preferably contains at least one of _{ZnO and CeO 2.}
In the present specification, "ZnO" includes ZnO doped with aluminum (Al) and ZnO doped with other elements.
Further, in the present specification, "CeO ₂ " is doped with gadolinium (Gd) -doped CeO ₂ (sometimes collectively referred to as _{CeGdO 2 ) (Ce 0.9} Gd _0.1 O ₂ etc.), samarium (Sm) doped. It has been CeO _2, and is intended to include CeO ₂ doped with other elements.
Further, these inorganic compounds may be used alone in the first transparent inorganic layer, or may be used in combination of two or more in the first transparent inorganic layer.

The thickness of the first transparent inorganic layer is preferably 70 nm or more, and preferably 400 nm or less. When the thickness of the first transparent inorganic layer is 70 nm or more, sufficiently high ultraviolet absorption characteristics can be obtained, and when it is 400 nm or less, the risk of productivity decrease and crack generation can be suppressed. can. From the same viewpoint, the thickness of the first transparent inorganic layer is more preferably 100 nm or more, and more preferably 300 nm or less.

<Second transparent inorganic layer>
Further, as shown in FIG. 4, the optical body 60 according to the present embodiment preferably includes a second transparent inorganic layer 65 on the first transparent inorganic layer 64 in addition to the first transparent inorganic layer 64. .. By providing the second transparent inorganic layer, it is possible to prevent the adhesion of dirt to the first transparent inorganic layer due to rain or the like. The second transparent inorganic layer has transparency and may be water-repellent or hydrophilic, and can be formed by, for example, a sputtering method or a CVD method.

The main component of the second transparent inorganic layer preferably has a bandgap larger than the bandgap of the main component of the first transparent inorganic layer, and more specifically, the bandgap of the main component of the first transparent inorganic layer. Is also preferably an inorganic compound having a bandgap larger than 4.0 eV. The band gap of the main component of the second transparent inorganic layer is larger than the band gap of the main component of the first transparent inorganic layer, preferably 4.0 eV or more, thereby improving the antifouling property of the first transparent inorganic layer. In addition, the antiglare property of the obtained optical body can be improved.
Specifically, examples of the preferred main component of the second transparent inorganic layer include inorganic compounds such as _{SiO 2} , SiN, SiON, and MgF _2. In other words, the second transparent inorganic layer preferably contains at least one of _{SiO 2} , SiN, SiON and MgF _2. Further, it is more preferable that the second transparent inorganic layer contains at least SiO _2.
These inorganic compounds may be used alone in the second transparent inorganic layer, or may be used in combination of two or more in the second transparent inorganic layer.

The thickness of the second transparent inorganic layer is preferably 20 nm or more, and more preferably 200 nm or less. When the thickness of the second transparent inorganic layer is 20 nm or more and 200 nm or less, the reflectance can be sufficiently reduced and the antiglare property can be improved more effectively. From the same viewpoint, the thickness of the second transparent inorganic layer is more preferably 40 nm or more, and more preferably 100 nm or less.

<Third transparent inorganic layer>
Further, as shown in FIG. 5, in the optical body according to the present embodiment, in addition to the first transparent inorganic layer 64 and the second transparent inorganic layer 65, the third transparent inorganic layer 66 is placed on the second transparent inorganic layer 65. It is preferable to further provide. By providing the third transparent inorganic layer, deterioration of the first transparent inorganic layer and the second transparent inorganic layer due to chemicals can be suppressed. The third transparent inorganic layer has transparency and may be water-repellent or hydrophilic, and can be formed by, for example, a sputtering method or a CVD method.

The third transparent inorganic layer can contain at least one of _{SiO 2} , SiN, SiON and MgF _{2 as a main component.} Further, it is preferable that the third transparent inorganic layer _{further contains ZrO 2} , Nb ₂ O ₅ , and SnO _{2 as additional components.} The ratio of the additional component in the third transparent inorganic layer is preferably 6% by mass or more and 50% by mass or less. When the ratio of the additional component is 6% by mass or more, the effect of improving chemical resistance can be sufficiently obtained, and when it is 50% by mass or less, the refractive index with the second transparent inorganic layer can be obtained. The difference can be kept moderate and the difficulty of optical design can be avoided. From the same viewpoint, the ratio of the additional component in the third transparent inorganic layer is more preferably 13% by mass or more, further preferably 20% by mass or more, and further preferably 30% by mass or less. Is more preferable. The additional component may be used alone or in combination of two or more.

The thickness of the third transparent inorganic layer is preferably 20 nm or more. When the thickness of the third transparent inorganic layer is 20 nm or more, a sufficiently high chemical resistance can be obtained. Further, the thickness of the third transparent inorganic layer is preferably 200 nm or less. When the thickness of the third transparent inorganic layer is 200 nm or less, it is possible to suppress a decrease in productivity and a risk of crack generation. From the same viewpoint, the thickness of the third transparent inorganic layer is more preferably 100 nm or less.

<Anti-fouling coat layer>
It is preferable that the optical body according to the present embodiment is provided with an antifouling coat layer on the outermost surface of the fine concavo-convex layer on the side of the fine concavo-convex surface. Specifically, it is preferable that the optical body according to the present embodiment is provided with an antifouling coat layer on a fine concavo-convex layer, a second transparent inorganic layer, or a third transparent inorganic layer. By providing the antifouling coat layer, it is possible to reduce the adhesion of dirt to the optical body, and it is possible to easily remove the attached dirt, so that the optical body exhibits the desired performance for a longer period of time. Can be done.
From the viewpoint of high adhesiveness, the antifouling coat layer is preferably provided on the second transparent inorganic layer or the third transparent inorganic layer containing _{SiO 2 as a main component.}

The main component of the antifouling coat layer may be water-repellent or hydrophilic, and may be oil-repellent or lipophilic. However, from the viewpoint of more effectively enhancing the antifouling property, the main component of the antifouling coat layer is preferably water-repellent and oil-repellent. Specifically, the antifouling coat layer preferably has a pure water contact angle of 110 ° or more, and more preferably 115 ° or more. As having these properties, the main component of the antifouling coat layer is preferably perfluoropolyether.

The antifouling coat layer preferably has a thickness of 5 nm or more, and preferably 20 nm or less, for example, 10 nm. When the thickness of the antifouling coat layer is 5 nm or more, the antifouling property of the optical body can be sufficiently enhanced, and when it is 20 nm or less, the uneven structure of the fine uneven layer can be avoided from being buried. can.

<Other layers>
The optical body according to the present embodiment is not particularly limited and may include other layers other than the above-mentioned layers.
For example, in order to firmly adhere the above-mentioned fine concavo-convex layer and the first transparent inorganic layer, the optical body according to the present embodiment may be provided with an adhesion layer between them. Examples of the adhesion layer include a SiO _x layer, and the thickness can be, for example, 2 nm or more and 10 nm or less. This adhesion layer can be formed by, for example, a sputtering method or a CVD method.

Further, it is preferable that the optical body according to the present embodiment is provided with an adhesive layer that absorbs visible light on the surface of the fine concavo-convex layer opposite to the surface of the fine concavo-convex layer. By providing an adhesive layer that absorbs visible light on the surface opposite to the finely uneven surface, the window material 80 in which the glass substrate 81 is laminated on the surface of the optical body provided with the adhesive layer 84 as shown in FIG. In, visible light transmitted through (any first transparent inorganic layer 64 and) fine concavo-convex layer 63 and incident on the adhesive layer 84, and (arbitrary first transparent inorganic layer 64,) fine concavo-convex layer 63 and adhesive layer. After passing through 84, it is reflected by the glass substrate 81 and efficiently absorbs visible light and the like incident on the adhesive layer 84 to reduce the visible light transmission rate and further improve the antiglare property while maintaining high viewability. can do. In addition, by using adhesive layers having different visible light absorption rates, there is an advantage that it becomes possible to easily prepare a product lineup having different glossiness.
The adhesive layer that absorbs visible light can be prepared, for example, by using an adhesive material in which a colorant such as a dye or a pigment that absorbs visible light is dispersed in an arbitrary ratio. ..
On the other hand, for example, when the proportion of dyes and pigments that absorb visible light is large and there are problems such as deterioration of adhesive strength and durability, a colorant such as dyes or pigments is contained. A base material that absorbs visible light or an inorganic film that absorbs visible light such as DLC may be laminated on the fine concavo-convex layer.

<Characteristics of optical body>
The optical body according to the present embodiment preferably has a glossiness of 40 or less at a measurement angle of 20 °. When the glossiness at a measurement angle of 20 ° is 40 or less, the antiglare property of the optical body can be sufficiently high. From the same viewpoint, the glossiness of the optical body at a measurement angle of 20 ° is more preferably 30 or less, and further preferably 20 or less.
The glossiness of the optical body at a measurement angle of 20 ° can be measured by the method used in the examples.

The optical body according to the present embodiment preferably has a transmitted image sharpness of 50% or more at an optical comb width of 2 mm. When the transmission image sharpness at an optical comb width of 2 mm is 50% or more, the viewability of the optical body can be sufficiently high. From the same viewpoint, the transmission image sharpness of the optical body at an optical comb width of 2 mm is more preferably 70% or more, further preferably 80% or more.
The transmission image sharpness of the optical body at an optical comb width of 2 mm can be measured by the method used in the examples.

The optical body according to the present embodiment preferably has a total haze of 15% or more and 60% or less. When the total haze is 15% or more, the antiglare property can be effectively enhanced, and when the total haze is 60% or less, the viewability can be effectively enhanced. From the same viewpoint, the total haze of the optical body is more preferably 50% or less.
Further, the optical body according to the present embodiment preferably has an internal haze of 4% or less. When the internal haze is 4% or less, the view can be further enhanced. From the same viewpoint, the internal haze of the optical body is more preferably 2% or less.
The total haze and the internal haze of the optical body can be measured by the method used in the examples.

Further, the optical body according to the present embodiment preferably has a transmittance of light having a wavelength of 320 nm of 10% or less, more preferably 6% or less, and further preferably 3% or less. When the transmittance of light having a wavelength of 320 nm or less of the optical body is 10% or less, deterioration such as yellowing of the base material due to ultraviolet rays can be effectively suppressed, and adhesion durability between the base material and the resin layer can be effectively suppressed. Can be improved.
The transmittance of light having a wavelength of 320 nm of the optical body can be measured by using, for example, "V-560" manufactured by JASCO Corporation.

(Window material)
The window material according to the embodiment of the present invention (hereinafter, may be referred to as “window material according to the present embodiment”) includes a glass substrate and the above-mentioned optical body. Specifically, as shown in FIG. 7, in the window material 80 according to the present embodiment, the above-mentioned optical body 60 and the glass substrate 81 are provided, and the surface of the optical body 60 opposite to the fine uneven surface is a glass substrate. It can be laminated so as to face the 81. As described above, the window material according to the present embodiment is provided with at least the above-mentioned optical body and is excellent in both anti-glare property and viewability. Can be suitably used.
The window material according to the present embodiment may be provided with the above-mentioned optical body on only one side of the glass substrate, or may be provided on both sides.

Further, based on the same concept as the above-mentioned optical body, the glossiness at a measurement angle of 20 °, the transmitted image sharpness at an optical comb width of 2 mm, the total haze, the internal haze, and the light having a wavelength of 320 nm in the window material according to the present embodiment. The preferable range of the transmittance and the reason why the range is preferable are the same as those described above for the optical body, respectively.

The window material according to this embodiment may be double glazing. In general, double glazing is inferior in anti-glare property to single-layer glass, but since the window material according to the present embodiment has the above-mentioned optical body, even if it is double glazing, it has high anti-glazing property. Can bring.

Here, in the double glazing, as shown in FIG. 8, a plurality of glass substrates (82, 83) are usually laminated with the spacer 85 interposed therebetween, and a space is formed between the glass substrates. Refers to glass with a structure.
As shown in FIG. 8A, the window material 80 according to the present embodiment, which is a multi-layer glass, is on the outdoor side of the glass substrate 82, which is the outdoor side when installed in a building or the like as a window glass. The optical body 60 may be provided only on the surface, and as shown in FIGS. 8B to 8D, the optical body 60 is provided on the outdoor side surface of the glass substrate 82 on the outdoor side. At the same time, the optical body 60 may be provided on one side and / or both sides of the glass substrate 83 on the indoor side, and further, as shown in FIGS. 8 (e) to 8 (h), the glass on the outdoor side. Optical bodies may be provided on both sides of the substrate 82, and optionally, optical bodies 60 may be provided on one side and / or both sides of the glass substrate 83 on the indoor side.

Further, when the window material according to the present embodiment is multi-layer glass and the optical body is provided on the outdoor side surface of the glass substrate which becomes the outdoor side when installed as a window glass in a building or the like. Is particularly preferably provided with an adhesive layer that absorbs visible light on the surface of the optical body opposite to the finely uneven surface (more specifically, between the optical body and the glass substrate). By providing the adhesive layer that absorbs such visible light, after transmitting the visible light transmitted through the optical body and incident on the adhesive layer, the optical body and the adhesive layer, and then on the indoor surface of the glass substrate on the outdoor side. After transmitting the visible light that is reflected and incident on the adhesive layer, and passes through the optical body, the adhesive layer, and the glass substrate on the outdoor side, it is reflected by the glass substrate on the indoor side and is transmitted through the glass substrate on the outdoor side to the adhesive layer. It is possible to efficiently absorb incident visible light and reduce the visible light transmittance, and to solve the problem of antiglare that the multilayer glass may frequently face while maintaining high viewability.

Next, the present invention will be described in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples.

(Examples 1 to 5, Comparative Examples 1 to 2)
A resin layer having a fine concavo-convex structure is formed on a PET substrate (Toyobo Co., Ltd., "A4300", thickness 75 μm) by a shape transfer method using a composition containing an acrylic ultraviolet curable resin. And obtained an optical body. In forming the fine uneven layer at this time, Table 1 shows each parameter (Ra: arithmetic average roughness (μm), RSm: average length (μm) of roughness curve element, specific surface area) related to the surface of the optical body. The conditions of the shape transfer method were appropriately adjusted, such as changing the surface shape of the master so that the values shown were obtained. Next, after laminating an adhesive layer (base material-less double-sided adhesive tape, "MHM-FW25" manufactured by Niei Kako Co., Ltd., thickness 25 μm) on the surface of this PET substrate opposite to the surface on which the resin layer was formed. , 3 mm thick blue plate glass (float plate glass specified by JIS R3202).

For the optical body (window material) to which the blue plate glass is bonded thus obtained, the arithmetic average roughness Ra, the average length RSm of the roughness curve element, and the specific surface area are measured and haze by the following method. Was measured, and anti-glare and viewability were evaluated.

<Measurement of arithmetic average roughness Ra, average length RSm of roughness curve element, specific surface area>
Using "NewView7300" manufactured by Canon Co., Ltd., according to ISO25178 and JIS B0601, the arithmetic average roughness Ra of the fine uneven surface, the average length RSm of the roughness curve element, and the specific surface area (area of the region in the unit region). The ratio of the surface area to the surface area) was measured. Specific conditions include software: MtroPro 8.3.5, Acquisition Mode: Scan, Scan Type: Bipolar, zoom lens: 2x, objective lens: 200x, mode: High 2G, surface correction: Cylinder, Camera Mode: It was set to 640 × 480 210 Hz. The above measurement was performed in a rectangular region of 35.3 μm × 26.5 μm arbitrarily selected from the fine uneven surface. The results are shown in Table 1.

<Measurement of haze>
All haze and internal haze were measured according to JIS K7136 using "NDH 7000SP" manufactured by Nippon Denshoku Kogyo Co., Ltd. The results are shown in Table 1.

<Evaluation of anti-glare>
Place the optical body (window material) to which the blue plate glass is attached on a flat surface with the blue plate glass facing down, and use a portable gloss meter ("Micro Gloss" manufactured by BYK Gardner) to comply with JIS Z8741. Then, the glossiness G at a measurement angle of 20 ° was measured. A non-reflective plate (Carbon Feather 188X1B, manufactured by Kimoto Co., Ltd.) was laid on the flat surface on which the optical body was placed to minimize the influence of the base. From the value of the glossiness G, the antiglare property was evaluated according to the following criteria. The results are shown in Table 1.
Glossiness G is 30 or less ... ◎
Gloss G is over 30 and 40 or less ... 〇 Gloss G is over 40 ... ×

<Evaluation of view>
Using a touch-sensitive image quality measuring instrument (“ICM-1T” manufactured by Suga Test Instruments Co., Ltd.), transmission of an optical body (window material) to which blue plate glass is attached in accordance with JIS K7374 with an optical comb width of 2 mm. Image sharpness T (%) was measured. From the value of the transmitted image sharpness T, the viewability was evaluated according to the following criteria. The results are shown in Table 1.
Transmission image sharpness T is 70% or more ... ◎
Transmission image sharpness T is 50% or more and less than 70% ... 〇 Transmission image sharpness T is less than 50% ... ×

From Table 1, in Examples 1 to 5, Ra is 0.2 μm or less, and at least one of RSm and the specific surface area is within a predetermined range. Therefore, it is possible to achieve both anti-glare property and viewability. You can see that it is done.

According to the present invention, it is possible to provide an optical body having excellent anti-glare property and viewability, and a window material having excellent anti-glare property and view property.

1 Shape transfer device 2 Master 23 Fine uneven structure 51 Base material supply roll 52 Winding roll 53, 54 Guide roll 55 Nip roll 56 Peeling roll 57 Coating device 58 Light source 60 Optical body 61 Base material 62 Resin layer 63 Fine uneven layer 64 1st Transparent Inorganic Layer 65 Second Transparent Inorganic Layer 66 Third Transparent Inorganic Layer 80 Window Material 81, 82,83 Glass Substrate 84 Adhesive Layer 85 Spacer

Claims (2)

A window material provided with a glass substrate and an optical body,
The optical body includes a fine concavo-convex layer and has a fine concavo-convex layer.
The fine uneven layer is composed of a base material and a resin layer having a fine uneven surface arranged on the base material.
In the rectangular region of 35.3 μm × 26.5 μm on the fine uneven surface,
Arithmetic mean roughness Ra is 0.096 μm or more and 0.2 μm or less, and
The average length RSm of the roughness curve element is 2 μm or more and 6 μm or less, and the ratio of the surface area to the area of the rectangle is 1.04 or more and 1.42 or less.
The total haze is 15% or more and 60% or less, the internal haze is 4% or less, the glossiness at a measurement angle of 20 ° is 40 or less, and the transmission image sharpness at an optical comb width of 2 mm is 70% or more. Oh Ru,
A window material that is characterized by that. The window material according to claim 1, wherein the optical body does not contain a transparent inorganic layer.

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