JP2017173614A - Optical body, and method for manufacturing optical body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical body which has a fine rugged shape, in which a gauge band is not generated, and whose appearance and optical performance are satisfactory.SOLUTION: An optical body has: a first optical layer 2 in a fine rugged shape; and a reflective layer 3, in which the first optical layer has: knurling parts on both ends in a widthwise direction; and areas with the fine rugged shapes formed inside the knurling parts, in layer thickness distribution of the first optical layer in the areas with the fine rugged shapes formed, a cross-sectional shape in a thickness direction thickening from both ends of the widthwise direction toward the center part has a projection, and at least one recessed area is formed in a layer thickness distribution curve of the projection of the first optical layer, and a recess amount to be represented by a formula (I) of the recessed area in the layer thickness distribution of the first optical layer is 4% or less. The recess amount=[(M-m)/m]×100(%)(I), m represents the smallest value of layer thickness of the first optical layer of a recessed part of the recessed area, and M represents the largest value of the layer thickness of the first optical layer in front of start of the recessed area.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an optical body and a method for manufacturing the optical body.

In recent years, in order to reduce the load of air conditioning, various optical films such as window films for shielding sunlight have been widely used.
In the manufacturing process of such an optical film, it is necessary to wind up the optical film used as a product in elongate form. However, in the wound roll, a streak-like wavy shape (called a gauge band or a black band) may occur in the longitudinal direction of the film. This defective shape causes problems such as distortion of the transmission image, poor appearance, and poor optical film quality. In order to prevent the occurrence of this gauge band, many problems such as product substrate physical properties, surface condition, thickness unevenness, process temperature, winding tension, etc. are caused by this shape defect problem in optical film rolls. Conventionally, there has been proposed a method of forming a convex portion on a part of a film called knurling and inserting thin side tapes at both ends of the film (see, for example, Patent Documents 1 to 3).

  By the way, in order to suppress the increase in heat island among window films that shield sunlight, a heat ray retroreflective film has recently been proposed (for example, see Patent Document 4).

Japanese Patent Laid-Open No. 2002- 211803 JP-A-2005-77795 JP 2009-223129 A JP2015-99397A

However, for an optical body having a transparent base material such as a heat ray retroreflective film, a fine uneven resin layer, and an optical layer including a reflective layer formed on the resin layer, a conventionally known gauge With the band generation prevention measure, it was not sufficient to prevent the gauge band.
Therefore, even when an optical body having an optical layer having a fine concavo-convex shape such as a heat ray retroreflective film is wound around a roll, it is possible to effectively prevent the occurrence of a gauge band, and optical that does not cause poor appearance or optical performance deterioration. The body was desired.

  An object of the present invention is to solve the above-described problems and achieve the following objects. That is, an object of the present invention is to provide an optical body having an optical layer having a fine concavo-convex shape, in which a wound band does not generate a gauge band and has good appearance and optical performance. To do.

Means for solving the problems are as follows. That is,
<1> A long optical body having a first optical layer having a fine irregular shape and a reflective layer formed on the first optical layer,
The first optical layer has a knurling portion at both ends in the width direction, and a region in which the fine uneven shape is formed inside the knurling portion,
In the region where the fine concavo-convex shape is formed, the layer thickness distribution of the first optical layer becomes thicker from both ends in the width direction toward the center, and the cross-sectional shape in the thickness direction has a convex shape. And the convex layer thickness distribution curve of the first optical layer is formed with at least one recessed region,
The optical body is characterized in that a dent amount represented by the following formula (I) of the dent region in the layer thickness distribution of the first optical layer is 4% or less.
Depression amount = [(M−m) / m] × 100 (%) (I)
In the above formula (I), m represents the smallest value of the thickness of the first optical layer in the recessed portion of the recessed area, and M represents the first optical layer before the recessed area starts. This represents the largest value of the layer thickness.
<2> The optical body according to <1>, wherein the first optical layer includes a transparent base material and a fine uneven layer.
<3> In the first optical layer, a difference Δt between a layer thickness of the first optical layer in the knurling portion and a layer thickness of the first optical layer in a region where the fine uneven shape is formed. Is the optical body according to <2>, wherein the thickness is 3% to 10% with respect to the layer thickness of the transparent substrate.
<4> The optical body according to any one of <1> to <3>, wherein the dent amount is 2% to 4%.
<5> The optical body according to any one of <1> to <4>, wherein the reflective layer includes at least a metal layer.
<6> The fine uneven shape of the first optical layer is formed by one of a one-dimensional array and a two-dimensional array of a large number of structures, and the structure has a prism shape, a lenticular shape, a hemispherical shape, and The optical body according to any one of <1> to <5>, wherein the optical body is in a corner cube shape.
<7> A long length having a fine uneven first optical layer formed by laminating a fine uneven transfer layer on a transparent substrate, and a reflective layer formed on the first optical layer. An optical body manufacturing method of
Using a transfer master, a transfer layer forming step of transferring a fine uneven shape to the transfer layer;
A reflective layer forming step of forming a reflective layer having at least a metal layer on the fine uneven shape;
In the transfer layer forming step, the temperature of the transfer master is set to 0 ° C. to 7 ° C. lower than the temperature of the transfer resin constituting the transfer layer,
The optical body is
The first optical layer has, in the width direction, a knurling portion at both ends, and a region in which a fine uneven shape is formed inside the knurling portion,
In the region where the fine concavo-convex shape is formed, the layer thickness distribution of the first optical layer becomes thicker from both ends in the width direction toward the center, and the cross-sectional shape in the thickness direction has a convex shape. And the convex layer thickness distribution curve of the first optical layer is an optical body in which at least one recessed region is formed.
This is a method for manufacturing an optical body.
<8> Furthermore, it is a manufacturing method of the optical body as described in said <7> which has an embedded layer formation process and the slit and the punching process cut into the optical body of a standard dimension.

  According to the present invention, the above-mentioned problems can be solved and the above-mentioned object can be achieved, and an optical body having an optical layer having a fine concavo-convex shape, in which a gauge band is generated in a wound roll. In addition, an optical body with good appearance and optical performance can be provided.

FIG. 1 is a cross-sectional view for explaining an example of the configuration of the optical body of the present invention. FIG. 2 is a cross-sectional view for explaining an example of the structure of the optical body of the present invention. FIG. 3A is a cross-sectional view for explaining the maximum value M of the layer thickness of the first optical layer before the start of the recessed area used for measuring the amount of the recessed area in the optical body of the present invention. FIG. 3B is a cross-sectional view for explaining the smallest value m of the layer thickness of the first optical layer in the recessed portion of the recessed area used for measuring the recessed amount of the recessed area in the optical body of the present invention. . FIG. 4A is a schematic diagram for explaining a problem that occurs when an optical body that does not have a knurling portion is wound with a roll. FIG. 4B is a schematic diagram for explaining a problem that occurs when a conventional optical body having a knurling portion is wound with a roll. FIG. 4C is a schematic diagram for explaining the effect exhibited by the optical body of the present invention when the optical body of the present invention is wound with a roll. FIG. 5 is a cross-sectional view for explaining the layer thickness of the optical body of the present invention. FIG. 6A is a cross-sectional view for explaining the relationship between the layer thickness of the knurling portion and the layer thickness of the first optical layer in the optical body of the present invention. FIG. 6B is a cross-sectional view for explaining the layer thickness distribution in the entire width direction in the optical body of the present invention. FIG. 7A is a cross-sectional view for explaining another example of the configuration of the optical body of the present invention. FIG. 7B is a cross-sectional view for explaining another example of the configuration of the optical body of the present invention. FIG. 7C is a cross-sectional view for explaining another example of the configuration of the optical body of the present invention. FIG. 8A is a process diagram for explaining an example of the method of manufacturing an optical body according to the present invention. FIG. 8B is a process diagram for explaining an example of the method for producing an optical body of the present invention. FIG. 8C is a process diagram for explaining an example of the method for producing an optical body of the present invention. FIG. 8D is a process diagram for describing an example of the method of manufacturing an optical body of the present invention. FIG. 8E is a process diagram for describing an example of the method of manufacturing an optical body of the present invention. FIG. 9 is a schematic view showing one configuration example of the optical body manufacturing apparatus of the present invention. FIG. 10 is a schematic view showing one configuration example of the optical body manufacturing apparatus of the present invention. FIG. 11A is a process diagram for describing another example of the method of manufacturing an optical body of the present invention. FIG. 11B is a process diagram for explaining another example of the method of manufacturing an optical body of the present invention. FIG. 12 is an explanatory diagram when a slit is formed in the optical body of the present invention. FIG. 13 is a schematic diagram for explaining an evaluation method for evaluating the optical body of the present invention performed in the examples. FIG. 14 is a schematic diagram for explaining an evaluation method for evaluating the optical body of the present invention performed in the examples. FIG. 15 is a cross-sectional view for explaining an example of the structure of the optical body of the present invention. FIG. 16 is a cross-sectional view for explaining the layer thickness of the optical body of the present invention.

(Optical body)
The optical body of the present invention is a long optical body.
The long optical body is wound around a cylindrical core and is usually wound around 200 or more times. A core having an inner diameter of 3 to 8 inches is usually used.
The optical body includes a fine concavo-convex first optical layer and a reflective layer formed on the first optical layer.
In the width direction, the first optical layer has a knurling portion at both ends and a region in which a fine uneven shape is formed inside the knurling portion.
In the region where the fine concavo-convex shape is formed, the layer thickness distribution of the first optical layer becomes thicker from both ends in the width direction toward the center, and the cross-sectional shape in the thickness direction has a convex shape. In the convex layer thickness distribution curve of the first optical layer, at least one concave region is formed.
The dent amount represented by the following formula (I) of the dent region in the layer thickness distribution of the first optical layer is 4% or less.
Depression amount = [(M−m) / m] × 100 (%) (I)
In the above formula (I), m represents the smallest value of the thickness of the first optical layer in the recessed portion of the recessed area, and M represents the first optical layer before the recessed area starts. This represents the largest value of the layer thickness.
The optical body having the above characteristics can maintain a good appearance and optical performance without generating a gauge band in the wound roll.

<Configuration of optical body>
The optical body of the present invention includes a first optical layer and a reflective layer, and further includes other layers as necessary.
FIG. 1 is a cross-sectional view for explaining the configuration of the optical body of the present invention. FIG. 1 shows an optical body 1 in which a first optical layer 2 has a fine uneven shape, and a reflective layer 3 is formed on the first optical layer 2. In the optical body 1, a concave second optical layer 6 is formed on the reflective layer 3 so as to make up the fine convex shape of the first optical layer.
In FIG. 1, the first optical layer 2 is formed of a transparent substrate 4 a and a concavo-convex layer 4 (resin layer having a concavo-convex shape: also referred to as a transfer layer 4 in the present invention). The optical layer 6 is formed of an embedding layer 5 which is a resin layer for embedding the fine uneven shape, and a transparent substrate 5a.
As the other layer, an adhesive layer, a release layer, or the like may be further provided on the second optical layer 6 in FIG.
The respective layers constituting the optical body will be described in detail below.

<Structure of optical body>
The structure of the optical body of the present invention will be described with reference to FIG. FIG. 2 is a schematic diagram showing a layer thickness distribution in the width direction of the first optical layer having a fine uneven shape. A solid line in FIG. 2 indicates a layer thickness distribution curve of the first optical layer.
That is, as shown in FIG. 2, the first optical layer has a knurling portion B formed at both ends in the width direction x, and a fine uneven shape is formed inside the knurling portion B. There is a region A. And the layer thickness distribution of the 1st optical layer in the area | region A in which the fine uneven | corrugated shape was formed becomes thick convex from the both ends of a width direction toward a center part, and the cross-sectional shape of the thickness direction y is gentle. And at least one recessed region is formed in the gently convex layer thickness distribution curve of the first optical layer.
That is, as shown in FIG. 2, when the first optical layer is viewed in a cross section in the thickness direction, the concave portion is formed in the shape of the convex portion indicated by the layer thickness distribution curve of the first optical layer.
A cross-sectional view in the width direction of the first optical layer at point R in FIG. 2 is shown in FIG. 3A. The point R is a point where the layer thickness of the first optical layer before the beginning of the recessed region is the largest. Moreover, FIG. 3B shows a cross-sectional view in the width direction of the first optical layer at the point Q in FIG. The point Q is a place where the layer thickness of the first optical layer in the recessed portion of the recessed region is the smallest.
In the knurling portion B in FIG. 2, a protruding portion having a convex shape is formed on the first optical layer in order to prevent the occurrence of a gauge band. Since the knurling process as used in the present invention is provided to prevent the occurrence of a gauge band, the scale is different from the convex part in the fine concavo-convex shape in the region A in FIG. The protrusion formed by the knurling process generally has a height of 2 μm to 15 μm. When used as a product, the knurling part is not used.

The present inventors have studied in detail the relationship between the problem that occurs when the optical body is wound on a roll and the thickness distribution of the optical layer in the width direction of the optical body, and have found the following. This will be described with reference to FIGS. 4A to 4C. Here, FIG. 4A shows a case where an optical body having no knurling portion is wound by a roll, FIG. 4B shows a case where a conventional optical body having a knurling portion is wound by a roll, and FIG. The case where the optical body of this invention is wound up with the roll is shown. 4A to 4C, column (1) indicates the layer thickness distribution in the width direction of the first optical layer as shown in FIG. The column (2) shows the winding shape when the optical film is wound around a roll after the concavo-convex shape is transferred to the transfer layer. The column (3) shows the winding shape when the optical film is wound on a roll after the embedding layer is arranged on the reflective layer.
When a film made of the first optical layer having a fine uneven shape is wound on a roll without taking any measures on the film (see column (1) in FIG. 4A), it is shown in column (2) in FIG. 4A. Thus, a gauge band appears in the vicinity of the center where the film thickness becomes particularly thick in the whole.
Therefore, when this film is provided with a knurling portion at both ends as in the prior art (see column (1) in FIG. 4B) and wound on a roll, as shown in column (2) in FIG. Although a gauge band is generated, a gauge band is not generated in the central portion which is a product part, and the quality of the product part is passed.
However, when the second optical layer as shown in FIG. 1 is formed on the first optical layer having a fine concavo-convex shape, that is, after FIG. 4B (2), the fine shape is further filled by coating or laminating. When the optical film is wound on a roll with respect to the optical film after embedding processing, as shown in FIG. 4B (3), there is a problem that a gauge band is raised in an area used as a product. If the gauge band emerges in a later process, the transmitted image is distorted, leading to problems of poor appearance and poor optical performance.
This gauge band problem seems to be affected by the flow pattern of the transfer resin constituting the transfer layer and the layer thickness distribution of the transfer layer.
As a result of repeated research, the inventors have found that when the layer thickness distribution of the transfer layer near the center of the film has a tendency to protrude upward, the gauge band becomes prominent, or even if the layer thickness distribution is uniform It was confirmed that a gauge band along the resin flow pattern appeared.

Therefore, the present inventors not only provide a knurling portion for the first optical layer, but also the layer thickness distribution of the first optical layer in the width direction in a region where a fine uneven shape is formed. On the other hand, an optical film having a convex shape that is thick at the center and thin at both ends, and provided with at least one concave region in the convex thickness distribution curve of the first optical layer was produced (FIG. 4C (1 )reference).
When the optical film is wound on a roll, as shown in the column (2) of FIG. 4C, a gauge band is generated at the end portion, but no gauge band is generated at the center portion, which is a product portion. In addition, a gauge band is generated in an area used as a product even for an optical film after embedding processing in which a fine shape is embedded by coating or laminating after FIG. 4C (2). We found that a product with acceptable quality was obtained.
The present invention has been made based on such knowledge.
Hereafter, each component which comprises the optical body of this invention is demonstrated.

<Each component of the optical body>
<< first optical layer >>
The first optical layer has a fine uneven shape and is transparent to visible light.
The first optical layer is not particularly limited as long as it is a support for supporting the reflective layer, and can be appropriately selected according to the purpose.
The first optical layer preferably has an uneven layer (also referred to as a transfer layer in the present invention) and a transparent substrate.

-Uneven layer (transfer layer)-
As transfer resin which comprises the said uneven | corrugated layer (transfer layer), resin, such as a thermoplastic resin, active energy ray curable resin, and a thermosetting resin, is mentioned, for example.
The transfer layer may have a characteristic of absorbing light of a specific wavelength in the visible region within a range not impairing transparency to visible light from the viewpoint of imparting design properties to an optical body, a window material, and the like. .
Design characteristics, that is, the property of absorbing light of a specific wavelength in the visible region can be performed, for example, by incorporating a pigment into the transfer layer.

-Transparent substrate-
There is no restriction | limiting in particular as a shape of a transparent base material, According to the objective, it can select suitably, For example, a film form, a sheet form, plate shape, block shape etc. are mentioned. As a material for the transparent substrate, for example, a known polymer material can be used. The known polymer material is not particularly limited and may be appropriately selected depending on the intended purpose. For example, polyethylene terephthalate (PET), polycarbonate (PC), triacetate (TAC), cycloolefin copolymer (COC), Examples thereof include cycloolefin polymer (COP).
There is no restriction | limiting in particular as layer thickness of a transparent base material, Although it can select suitably according to the objective, It is preferable that it is 23 micrometers-125 micrometers from a viewpoint of productivity.
As the transparent substrate, as shown in FIG. 5, a water-repellent hard coat layer 4b may be provided in addition to the transparent substrate 4a such as PET. The hard coat layer (HC layer) refers to something like an acrylic resin. Moreover, there is no restriction | limiting in particular as thickness of a hard-coat layer, Although it can select suitably according to the objective, It is preferable that they are 1 micrometer-6 micrometers.

-Fine irregular shape-
The first optical layer has a plurality of fine irregularities, but the “irregularity” may be only a convex portion or only a concave portion depending on how the reference surface is taken, and is referred to in the present invention. The “concavo-convex portion” is intended to include any shapes of convex portions, concave portions, and concave-convex portions.
The pitch of the fine uneven shape of the first optical layer is not particularly limited and may be appropriately selected depending on the intended purpose, but is preferably 300 μm or less, more preferably 200 μm or less, and particularly preferably 20 μm to 150 μm. .
There is no restriction | limiting in particular as a measuring method of the uneven | corrugated shaped pitch of a said 1st optical layer, According to the objective, it can select suitably, For example, observation with an optical microscope, cross-sectional observation of SEM, etc. are mentioned.
Here, the pitch of the concavo-convex shape of the first optical layer indicates P shown in FIG. That is, it is the distance between one end and the other end of the concavo-convex shape of the first optical layer. However, when the concavo-convex shape includes a plurality of pitches, the average is taken.
The uneven shape of the first optical layer is formed by either a one-dimensional array or a two-dimensional array of a large number of structures. There is no restriction | limiting in particular as said structure, According to the objective, it can select suitably, For example, prism shape, lenticular shape, hemispherical shape, corner cube shape etc. are mentioned.

The layer thickness of the first optical layer will be described based on the configuration diagram of the optical body in the width direction of FIG.
In FIG. 5, (i) is the thickness of the first optical layer, (ii) is the thickness of the uneven portion of the transfer layer 4, (iii) is the thickness of the ridge portion of the transfer layer 4, and (iv) is the transparent substrate. 4a (or including the case where the transparent base material 4a and the hard coat layer 4b are combined) represents the layer thickness of the base material portion.
Here, the thickness of the collar portion is preferably 4% to 20% of the layer thickness of the base material portion. It is because the dent area | region which has a desired dent amount can be formed as the thickness of a collar part is in the said range. In particular, the thickness of the collar portion is preferably 2 μm or more. This is because if it is 1 μm or less, problems such as white turbidity may occur in the final product.

-Knurling part-
In the first optical layer, the difference Δt between the layer thickness of the first optical layer in the knurling portion and the layer thickness of the first optical layer in the region where the fine concavo-convex shape is formed is shown in FIG. As shown by, it is preferably 3% to 10% with respect to the layer thickness of the base material portion.
The protruding part of the convex shape of the knurling part can be formed by providing an uneven part at both ends of the transfer master and adjusting so that the film thickness distribution is generated during transfer.

-Regarding the layer thickness distribution of the first optical layer-
The layer thickness distribution of the first optical layer in the region where the fine concavo-convex shape is formed becomes thicker from both ends in the width direction toward the center, the cross-sectional shape in the thickness direction has a convex shape, In addition, the convex layer thickness distribution curve of the first optical layer has at least one concave region.
In the present invention, the convex layer thickness distribution curve of the first optical layer is formed with a concave region for preventing distortion that may occur when the optical body is wound on a roll. It is.
Here, as a method for changing the layer thickness distribution of the first optical layer so that the above-described gently convex shape and the recessed region can be formed, the temperature of the transfer master and the transfer resin can be adjusted. Can be mentioned. When the temperature of the transfer resin is raised with respect to the master for transfer, the present inventors can reduce the viscosity of the resin, and the thickness of the resin layer can be reduced in the vicinity of the supply portion to which the transfer resin is supplied in the manufacturing process. I found.
Therefore, the layer thickness distribution of the first optical layer may be controlled by adjusting the temperature of the transfer resin, the temperature of the transfer master, the nip roll shape, and the like. First, the temperature of the transfer resin is adjusted to optimize the moldability, reactivity, and defoamability during manufacturing, and then the temperature of the transfer master is adjusted to be equal or slightly lower than the transfer resin temperature. A region is formed. Further, at that time, crown processing may be added to the nip roll. The temperature of the transfer master is preferably set to 0 ° C. to 7 ° C. lower than the temperature of the transfer resin.

The layer thickness distribution of the first optical layer may be formed with at least one recessed region.
In the transfer layer forming process described below, when the transfer resin is supplied from the resin supply unit to the master disk or the transparent substrate, when the resin supply position is one place, the resin supply position is the width direction in the width direction. The central portion of the first optical layer may be in the vicinity of the central portion, and the concave region may be formed in the vicinity of the central portion.
There may be several resin supply positions. In that case, the resin supply position may be appropriately selected in consideration of the size of the region where the fine unevenness is formed, the supply width of the resin supply portion, and the like. At this time, the recessed area may be formed at a location corresponding to the plurality of resin supply positions.

−Dent amount−
As the degree of dent in the dent area, the dent amount calculated by the following formula (I) is 4% or less. Further, the dent amount is preferably 1% to 4%, more preferably 2% to 4%, further preferably 2% to 3.4%, and 2% to 3%. It is particularly preferred.
Depression amount = [(M−m) / m] × 100 (%) (I)
Here, in the above formula (I), m represents the smallest value of the layer thickness of the first optical layer in the recessed portion of the recessed region, as shown in FIG. 3B, and M represents the value in FIG. 3A. As shown by the above, it represents the largest value of the layer thickness of the first optical layer just before the indented region starts. 3A and 3B, when the hard coat layer 4b is further provided under the transparent substrate 4a, the thickness of the hard coat layer is added to the values of M and m in the above formula (I). The dent will be calculated.
When the dent amount is larger than 4%, the winding form wound on the roll is changed from a cylindrical shape to a polygonal column shape, and another mode failure such as a horizontal step may occur.
The dent amount is obtained by processing a cross section of the optical body in the width direction with a microtome, observing with a SEM or an optical microscope, measuring the layer thickness of the optical layer with image software, and substituting the value into the above formula (I) Can be obtained.

-Layer thickness distribution in the entire width direction in the optical body of the present invention-
The total layer thickness distribution in the width direction of the optical body of the present invention is preferably 7% or less, and more preferably 5% or less.
Here, the total layer thickness distribution is a value obtained by subtracting the minimum film thickness from the maximum film thickness of the first optical layer when the knurling portion and the recessed region are excluded, and The ratio to the minimum film thickness is expressed by the following formula (II).
Overall layer thickness distribution =
[(TMAX-tmin) / tmin] × 100 (%) (II)
In the above formula (II), TMAX represents the maximum film thickness of the first optical layer when the knurling part and the recessed area are excluded, and tmin excludes the knurling part and the recessed area. Represents the minimum thickness of the first optical layer.
The TMAX and the tmin correspond to the TMAX and tmin portions in FIG. 6B and indicate the length of the portion (i) in FIG.
If the overall layer thickness distribution is greater than 7%, weak gauge bands may occur on both sides of the recess. However, in this case, the optical body can be used if it is used in the vicinity of the floor or ceiling instead of the height of the line of sight.

<< Reflection layer >>
The reflective layer includes at least a metal layer, preferably a high refractive index layer, and further includes other layers as necessary.
The reflective layer is formed on the convex shape of the first optical layer.
The reflective layer reflects light containing at least infrared light.
There is no restriction | limiting in particular as layer thickness of the said reflection layer, Although it can select according to the objective, 20 micrometers or less are preferable, 5 micrometers or less are more preferable, and 1 micrometer or less are especially preferable.

-Metal layer-
There is no restriction | limiting in particular as a material of the said metal layer, According to the objective, it can select suitably, For example, a metal simple substance, an alloy, etc. are mentioned.

<< second optical layer >>
The second optical layer has, for example, a concave shape that fills the convex shape of the first optical layer.
The second optical layer is a layer for improving the transmission map definition and the total light transmittance and protecting the reflection layer.
As shown in FIG. 1, the second optical layer 6 is preferably formed of an embedding layer 5 and a transparent substrate 5a.
The embedding layer 5 is a resin layer for embedding the fine concavo-convex shape, and the embedding resin constituting the embedding layer 5 is not particularly limited and may be appropriately selected depending on the purpose. Examples thereof include resins such as thermoplastic resins such as polycarbonate and active energy ray-curable resins such as acrylic.
The transparent substrate 5a can be the same as the transparent substrate 4a described above.
The second optical layer has a characteristic of absorbing light of a specific wavelength in the visible region within a range not impairing transparency to visible light from the viewpoint of imparting design properties to an optical body or a window material. May be.
Design characteristics, that is, the property of absorbing light having a specific wavelength in the visible region can be achieved, for example, by incorporating a pigment into the second optical layer.

<< Other layers >>
An adhesive layer, a release layer, or the like may be provided as the other layer.

<Another aspect of configuration of optical body>
The optical body of the present invention may have a configuration shown in FIGS. 7A to 7C. As shown in FIG. 7A, a water-repellent hard coat layer 4b may be provided as the base portion in addition to the transparent base material 4a such as PET. Further, as shown in FIG. 7B, an optical body in which only an embedding layer made of an embedding resin is formed on the reflection layer may be used. Furthermore, as shown in FIG. 7C, an optical body having a configuration in which other layers such as an adhesive layer 7 and a release layer 8 are further added on the second optical layer may be used.
In the present invention, since the layer thickness distribution of the first optical layer is characteristic, the layer structure of the optical layer is not particularly limited and can be appropriately selected according to the purpose. The structure of the optical body of the heat ray retroreflective film described in JP-A-2015-99397 can be applied.

<Optical body manufacturing method>
The method for producing an optical body of the present invention includes at least a transfer layer forming step and a reflective layer forming step, and further includes other steps as necessary.

<Transfer layer forming step>
The transfer layer forming step is not particularly limited as long as it is a step of forming a transfer layer having a convex shape using a transfer master having a concave shape, and can be appropriately selected according to the purpose.
In the transfer layer forming step, when the transfer layer having the convex shape is formed using the transfer master having the concave shape (hereinafter also referred to as “mold”), the transfer layer having the concave shape is formed. By controlling the surface roughness of the master, the roughness of the convex shape can be controlled.

As a method for controlling the surface roughness of the transfer master having the concave shape, for example, a uniform nickel phosphorus plating having no micropores or small micropores is applied to a master substrate such as a SUS roll, and the micropores There is a method of ultra-precise cutting of a uniform nickel-phosphorus plated surface with no or small pores, a method of cutting a base material such as a SUS roll plated with an arbitrary cutting tool (cutting tool) with different wear, etc. Can be mentioned.
In the present invention, in the transfer layer forming step, the temperature of the transfer master is preferably adjusted to be equal to or slightly lower than the temperature of the transfer resin constituting the transfer layer. More specifically, the temperature of the transfer master is preferably set to be 0 ° C. to 7 ° C. lower than the temperature of the transfer resin.

<Reflective layer forming step>
The reflective layer forming step is not particularly limited as long as it is a step of forming a reflective layer on the first optical layer, and can be appropriately selected according to the purpose.

<Second optical layer forming step>
The second optical layer forming step is not particularly limited as long as it is a step of forming a second optical layer on the reflective layer, and can be appropriately selected according to the purpose. For example, the reflective layer The process of apply | coating and hardening | curing active energy ray curable resin on the top is mentioned.

Another example of the method for manufacturing the optical body will be described.
A uniform nickel-phosphorous plating with no micropores or small micropores is formed on a master substrate such as a SUS roll, and the plated surface is cut using a tool (cutting tool), ultra-precise cutting, laser processing, etc. Cutting is further performed to prepare a master for transfer (hereinafter also referred to as “mold”) having the same convex shape as the structure or its inverted shape.

  As shown in FIG. 8A, in order to laminate a transfer resin layer having a concavo-convex shape on a base material portion in which a transparent base material 4a is laminated on a hard coat layer 4b, the transfer master layer is used to form a transfer resin layer. The following transfer layer forming step is performed.

  For example, the convex shape of the mold is transferred to a film-like or sheet-like resin material using a melt extrusion method, a transfer method, or the like. Examples of the transfer method include a method of pouring an active energy ray-curable resin composition into a mold and irradiating and curing the active energy ray, and a method of transferring a shape by applying heat and pressure to the resin. For example, the transfer resin is supplied from the resin supply unit to the transparent substrate or the transfer master. Even if the transfer resin is applied on the transparent substrate 4 and the transfer master is in close contact with the transfer resin, the resin is cured to form a concavo-convex transfer layer. After the is cured to form a concavo-convex shaped transfer layer, it may be bonded to the transparent substrate 4a in any manner. However, it is more preferable in terms of quality to supply it to the transfer master. As described above, as shown in FIG. 8B, the first optical layer 2 (including the transfer resin layer 4, the transparent base material 4a, and the hard coat layer 4b) is obtained.

  Next, as shown in FIG. 8C, the reflective layer 3 is formed on the surface of the transfer resin layer 4. Examples of the method for forming the metal layer of the reflective layer 3 include a sputtering method, a vapor deposition method, a CVD (Chemical Vapor Deposition) method, a dip coating method, a die coating method, a wet coating method, and a spray coating method.

Next, as shown in FIG. 8D, a transparent base material 5a is disposed on the upper part of the reflective layer 3 to form a nip portion.
An embedded resin that is an active energy ray-curable resin is supplied to the nip portion.
Next, the embedded resin is cured by irradiating the embedding resin with UV light from the transparent substrate 5 a to form the embedding layer 5.

Through such an embedded layer forming step, the second optical layer 5 having a smooth surface is formed on the reflective layer 3 as shown in FIG. 8D.
Furthermore, the optical body of FIG. 8E may be formed by adhering each layer of the adhesive layer 7 and the release layer 8 on the transparent substrate 5a.

Another example of the method for manufacturing the optical body will be described.
A uniform nickel-phosphorous plating with no micropores or small micropores is formed on a master substrate such as a SUS roll, and the plated surface is cut using a tool (cutting tool), ultra-precise cutting, laser processing, etc. Cutting is further performed to prepare a mold having the same convex shape as that of the structure or an inverted shape thereof.

  Next, the convex shape of the mold is transferred to a film-like or sheet-like resin material using, for example, a melt extrusion method or a transfer method. Examples of the transfer method include a method of pouring an active energy ray-curable resin composition into a mold and irradiating and curing the active energy ray, and a method of transferring a shape by applying heat and pressure to the resin. Thereby, the 1st optical layer which has a fine uneven | corrugated shape in a main surface is formed.

Using the manufacturing apparatus shown in FIG. 9, a first optical layer with a reflective layer is produced as follows.
The manufacturing apparatus shown in FIG. 9 is a manufacturing apparatus for sputtering, and includes an unwinding roll 101, a support roll 102, a winding roll 103, and a sputter target 104.
The first optical layer 2 is sputtered using the sputter target 104 in a state in which the long first optical layer 2 is sent to the support roll 102 while being in close contact with the unwinding roll 101 and is in close contact with the support roll 102. A reflective layer is formed on the second convex shape (structure). The first optical layer 2 on which the reflective layer is formed is conveyed to the take-up roll 103 via the support roll 102 and taken up.

Then, the optical body 1 is produced as follows using the manufacturing apparatus shown in FIG.
First, the configuration of this manufacturing apparatus will be described. This manufacturing apparatus includes an unwinding roll 51, an unwinding roll 52, a winding roll 53, laminate rolls 54 and 55, guide rolls 56 to 60, a coating apparatus 61, and an irradiation apparatus 62.

  Each of the unwinding roll 51 and the unwinding roll 52 has a belt-like base material 5a and a first optical layer 2 with a belt-like reflective layer 3 (the first optical layer with the reflective layer is collectively denoted by reference numeral 9). It is wound in a roll shape and is arranged so that the base 5a and the first optical layer 9 with the reflective layer can be continuously sent out by the guide rolls 56, 57 and the like. The arrow in the figure indicates the direction in which the substrate 5a and the first optical layer 9 with the reflective layer are conveyed. The first optical layer 9 with a reflective layer is the first optical layer 2 in which the reflective layer 3 is formed on a convex shape (structure).

  The take-up roll 53 is arranged so that the belt-like optical body 1 produced by this manufacturing apparatus can be taken up. The laminating rolls 54 and 55 are arranged so that the first optical layer 9 with a reflective layer fed from the unwinding roll 52 and the base material 5 a sent from the unwinding roll 51 can be nipped. The guide rolls 56 to 60 are arranged on a conveyance path in the manufacturing apparatus so that the first optical layer 9 with a belt-like reflection layer, the belt-like base material 5a, and the belt-like optical body 1 can be carried. The material of the laminate rolls 54 and 55 and the guide rolls 56 to 60 is not particularly limited, and a metal such as stainless steel, rubber, silicone, or the like can be appropriately selected and used according to desired roll characteristics. .

  As the coating device 61, for example, a device including coating means such as a coater can be used. As the coater, for example, a coater such as a gravure, a wire bar, or a die can be appropriately used in consideration of the physical properties of the resin composition to be applied. The irradiation device 62 is an irradiation device that irradiates active energy rays such as electron beams, ultraviolet rays, visible rays, and gamma rays.

Then, the manufacturing method of the optical body using this manufacturing apparatus is demonstrated.
First, the base material 5 a is sent out from the unwinding roll 51. The fed base material 5 a passes under the coating device 61 through the guide roll 56. Next, the active energy ray-curable resin is applied by the coating device 61 onto the base material 5 a that passes under the coating device 61. Next, the base material 5a coated with the active energy ray curable resin is conveyed toward the laminate roll. On the other hand, the first optical layer 9 with a reflective layer is fed out from the unwinding roll 52 and conveyed toward the laminating rolls 54 and 55 through the guide roll 57.

  Next, the carried-in base material 5a and the 1st optical layer 9 with a reflection layer are laminated roll 54, 55 so that a bubble may not enter between the base material 5a and the 1st optical layer 9 with a reflection layer. And the first optical layer 9 with the reflective layer is laminated on the base material 5a. Next, while conveying the base material 5a laminated | stacked by the 1st optical layer 9 with a reflection layer along the outer peripheral surface of the lamination roll 55, active energy ray curable resin is used from the base material 5a side by the irradiation apparatus 62. FIG. An active energy ray is irradiated to harden the active energy ray-curable resin. As a result, the base 5a and the first optical layer 9 with a reflective layer are bonded together via a resin layer (hereinafter referred to as the resin layer 5) that is a cured product of the active energy ray-curable resin, and the target optical A body 1 is produced. Next, the produced belt-like optical body 1 is conveyed to the take-up roll 53 through the guide rolls 58, 59, 60, and the optical body 1 is taken up by the take-up roll 53.

Furthermore, another example of the method for manufacturing the optical body will be described.
As shown in FIG. 8C, after the reflective layer forming step is performed and the reflective layer 3 is formed on the first optical layer 2, an embedding resin is formed on the reflective layer 3 by a coating method as shown in FIG. 11A. You may form the embedding layer 5 which consists of. Subsequently, the adhesive layer 7 and the release layer 8 may be adhered to the embedding layer 5 to form the optical body of FIG. 11B.

<< Other processing steps >>
After producing a desired optical body, as shown in FIG. 12, a processing step for inserting a slit may be further added. A slit-shaped optical body that can be used only in a region having a better film shape can be manufactured by inserting a slit so as to exclude a portion corresponding to a supply position for supplying the transfer resin at the time of manufacture and a knurling portion.
By subjecting the long optical body of the present invention to a slit / punching process, an optical body cut to a standard size can be obtained.
In a preferred embodiment of the method for producing an optical body of the present invention, in addition to the transfer layer forming step and the reflective layer forming step, the embedded layer forming step and the slit / punching step are further included.

<Characteristics of optical body>
One method for evaluating the roll winding appearance after the optical body transfer step is to measure roll hardness.
In the optical body of the present invention, when the film after the transfer process is wound on a roll and the roll film is measured for the roll hardness distribution with a contact-type roll hardness meter, the difference in roll hardness (the maximum and minimum roll hardness values) The difference) is 250 g or less, more preferably 200 g or less, and particularly preferably 150 g or less.

<Usage of optical body>
The elongated optical body of the present invention may be cut out to a predetermined size through a slit / punching process and used on a sheet (in a sheet).

Examples of the present invention will be described below, but the present invention is not limited to these examples.
Further, in each of the following examples and comparative examples, in the transfer layer forming step, the resin supply position for supplying the transfer resin is a central position with respect to the width direction of the region where the fine uneven shape is formed (one Supply).

Example 1
A uniform nickel-phosphorous plating without micropores was formed on a SUS roll, and the plated surface was ultra-precisely cut to obtain a master for transfer. After the transfer master was washed, shape transfer was performed using a thermosetting resin to form a transfer layer having a fine uneven shape. A transfer layer was formed on a transparent substrate (PET) having a thickness of 50 μm, and a first optical layer having a fine uneven shape was formed.
In the transfer layer forming step for transferring the shape, the transfer resin is formed so that the entire thickness distribution of the first optical layer is 7%, and the amount of the recessed area formed in the central portion is 2%. Was set to 51 ° C., and the temperature of the transfer master was set to 51 ° C. The temperature of the transfer resin was set in consideration of moldability, reactivity, defoaming property and the like.

The thickness of the obtained first optical layer was 76.0 μm at the point R in FIG. 15, 74.5 μm at the point Q, 71.0 μm at the point T, and 73.0 μm at the point U.
The layer thickness of each component of the first optical layer of Example 1 is as follows.
Values at point R in FIG. 15: (i) 76.0 μm, (ii) 14 μm, (iii) 8 μm, (iv-1) PET substrate 50 μm, (iv-2) HC layer 4 μm, (vi) ) 30 μm.
Values at point Q in FIG. 15: In FIG. 16, (i) 74.5 μm, (ii) 14 μm, (iii) 6.5 μm, (iv-1) PET substrate 50 μm, (iv-2) HC layer 4 μm, (Vi) 30 μm.
The dent amount in the optical body of Example 1 is [(76-74.5) /74.5] × 100 = 2% from the formula (I).
Further, the overall layer thickness distribution in the optical body of Example 1 is [(76−71) / 71] × 100 = 7% from the formula (II).

Next, the structure A [GZO (gallium-doped zinc oxide) / AgNdCu / GZO / AgNdCu / GZO] is formed in this order on the surface of the first optical layer having the convex shape by vacuum sputtering. Thus, GZO / AgNdCu / GZO / AgNdCu / GZO were alternately laminated in a direction perpendicular to the inclined surface to form a reflective layer. In addition, the alloy target containing the composition of Ag / Nd / Cu = 99.0 at% / 0.4 at% / 0.6 at% was used for film-forming of the AgNdCu layer (metal layer) which is a silver alloy layer. A ceramic target having a composition of Ga ₂ O ₃ / ZnO = 1 at% / 99 at% was used for forming the GZO layer (high refractive index layer). The high refractive index layer was formed using a roll in a state where the back side of the film formation surface of the PET film as a substrate was supported by the roll.
Thus, a first optical layer with a reflective layer was obtained.
Next, the reflective layer was embedded with an ultraviolet curable resin to obtain an optical body.
The layer thickness of the embedded layer was 20 μm. The optical body film after embedding layer formation was wound up on the roll (roll film of a product aspect).

The optical film of the present invention obtained after the transfer step by the above production method is wound on a roll, and the roll film is wound with a contact-type roll hardness meter (manufactured by TAPIO Technologies) on the rolled film (see FIG. 13). Distribution was measured.
[Evaluation criteria]
○: Roll hardness difference is 200 g or less. Δ: Roll hardness difference is larger than 200 g and 250 g or less. X: Roll hardness difference is larger than 250 g.

Moreover, the film was peeled off from the roll film of the said product aspect, and the base-material whole width was cut off to the size of the length of 100 cm. This sheet-like optical body was visually evaluated in a manner generally used. In FIG. 14, symbol (a) represents a lattice background, and symbol (b) represents a product (sheet-like optical body of the present invention). As shown in FIG. 14, this optical body is placed at the position (b) at a position 90 cm away from a person, and a grid-like background is placed at the position (a) at a distance of 3 m from this optical body, in a bright room. Then, transmission observation by humans was performed, and the distortion of the lattice background was confirmed. The grid background used was a white background and the grid was black printed. The grid pitch shown in FIG. 14 was 50 mm and the grid thickness was 5 mm.
[Evaluation criteria]
◯: Level at which the defective position is pointed out and is not known unless it is watched △: Level that can be understood by paying attention even if the defective position is not pointed out ×: Level that can be understood without staring at Table 1 shows the evaluation results of Example 1 .

(Example 2 to Example 6)
In contrast to Example 1, except that the thickness of the transparent substrate, the amount of dents, and the overall layer thickness distribution were changed as shown in Table 1, an optical body was prepared in the same manner as in Example 1, wound up on a roll, and film Got a roll.
In Example 2, the temperature of the transfer master was set 4 ° C. lower than the temperature of the transfer resin, and in Example 3, 7 ° C. was set lower.
In Example 4, the temperature of the transfer master was set 4 ° C. lower than the temperature of the transfer resin. Example 5 was set 2 ° C. lower and Example 6 was set 5 ° C. lower. In Example 4, the transfer nip roll was changed from a cylindrical one to an inverted crown shape.
Evaluations similar to Example 1 were performed on the optical bodies of Examples 2 to 6, and the results are shown in Table 1.

(Comparative Example 1 to Comparative Example 3)
In contrast to Example 1, except that the thickness of the transparent substrate, the amount of dents, and the overall layer thickness distribution were changed as shown in Table 1, an optical body was prepared in the same manner as in Example 1, wound up on a roll, and film Got a roll.
In Comparative Example 1, the temperature of the transfer master is set to be 15 ° C. lower than the temperature of the transfer resin. In Comparative Example 2, the temperature of the transfer master is set to be 6 ° C. higher than the temperature of the transfer resin. The temperature of the transfer master was set 10 ° C. higher than the temperature of the transfer resin.
Evaluation similar to Example 1 was performed with respect to the optical bodies of Comparative Examples 1 to 3, and the results are shown in Table 1.

(Comparison with Examples 1 to 3 and Comparative Example 2)
In order to show that the temperature setting of the transfer master and the transfer resin contributes to the adjustment of the dent amount, the temperature conditions of the transfer master and the transfer resin in Examples 1 to 3 and Comparative Example 2 and the result obtained are shown. Table 2 summarizes the results of the appearance of the dent amount of the obtained optical body and the appearance of the film roll in the wound form (product form) after embedding.

As described above, from the results of Examples 1 to 6, it was confirmed that the optical body of the present invention was an optical body with good appearance and optical performance without generating a gauge band in the wound roll.
In Example 4, since the total layer thickness distribution was set to 14%, there was weak distortion, but this was not at a level causing a problem in appearance as a product. In Examples 5 and 6, the thickness of the transparent substrate was increased, but no problem was caused in appearance.
As shown in Comparative Example 1, when the dent amount in the dent area is larger than 4%, the difference in roll hardness of the film roll after the transfer process is increased, distortion is confirmed at the product level, and the visual appearance is rejected. became. As shown in Comparative Example 2, there is no problem in the roll hardness difference unless the dent area is formed, but streaks appear in the wound form after embedding at the product level, and the visual appearance is rejected. . As shown in Comparative Example 3, when the dent amount was negative (that is, convex), the difference in roll hardness of the film roll after the transfer process was large, and the visual appearance was rejected at the product level.

The optical body of the present invention having an optical layer having a fine concavo-convex shape is suitable as a heat ray reflective optical member because a gauge band does not occur in a wound roll and a good appearance and optical performance can be maintained. Used.
Specifically, it is used by being bonded to a rigid body mainly having transparency with respect to light other than the transmitted specific wavelength, for example, a window material via an adhesive or the like. Examples of window materials include architectural window materials for high-rise buildings and houses, vehicle window materials, and the like.

DESCRIPTION OF SYMBOLS 1 Optical body 2 1st optical layer 3 Reflective layer 4 Transfer layer 4a Transparent base material 4b Hard coat layer 5 Embedding layer 5a Transparent base material 6 2nd optical layer 7 Adhesive layer 8 Release layer 9 1st with the reflective layer 3 Optical layer 2
DESCRIPTION OF SYMBOLS 51 Unwinding roll 52 Unwinding roll 53 Winding roll 54 Laminating roll 55 Laminating roll 56 Guide roll 57 Guide roll 58 Guide roll 59 Guide roll 60 Guide roll 61 Application apparatus 62 Irradiation apparatus 101 Unwinding roll 102 Support roll 103 Winding roll 104 Sputter target x width direction y thickness direction

Claims (8)

A long optical body having a first optical layer having a fine uneven shape and a reflective layer formed on the first optical layer,
The first optical layer has a knurling portion at both ends in the width direction, and a region in which the fine uneven shape is formed inside the knurling portion,
In the region where the fine concavo-convex shape is formed, the layer thickness distribution of the first optical layer becomes thicker from both ends in the width direction toward the center, and the cross-sectional shape in the thickness direction has a convex shape. And the convex layer thickness distribution curve of the first optical layer is formed with at least one recessed region,
An optical body, wherein a dent amount represented by the following formula (I) of the dent region in the layer thickness distribution of the first optical layer is 4% or less.
Depression amount = [(M−m) / m] × 100 (%) (I)
In the above formula (I), m represents the smallest value of the thickness of the first optical layer in the recessed portion of the recessed area, and M represents the first optical layer before the recessed area starts. This represents the largest value of the layer thickness.   The optical body according to claim 1, wherein the first optical layer has a transparent substrate and a fine uneven layer.   In the first optical layer, the difference Δt between the layer thickness of the first optical layer in the knurling portion and the layer thickness of the first optical layer in the region where the fine uneven shape is formed is The optical body according to claim 2, which is 3% to 10% with respect to the layer thickness of the transparent substrate.   The optical body according to any one of claims 1 to 3, wherein the dent amount is 2% to 4%.   The optical body according to claim 1, wherein the reflective layer has at least a metal layer.   The fine uneven shape of the first optical layer is formed by one of a one-dimensional array and a two-dimensional array of a large number of structures, and the structure has a prism shape, a lenticular shape, a hemispherical shape, and a corner cube shape. The optical body according to claim 1, which is any one of the above. A long optical body having a fine concavo-convex shaped first optical layer in which a fine concavo-convex shaped transfer layer is laminated on a transparent substrate, and a reflective layer formed on the first optical layer. A manufacturing method of
Using a transfer master, a transfer layer forming step of transferring a fine uneven shape to the transfer layer;
A reflective layer forming step of forming a reflective layer having at least a metal layer on the fine uneven shape;
In the transfer layer forming step, the temperature of the transfer master is set to 0 ° C. to 7 ° C. lower than the temperature of the transfer resin constituting the transfer layer,
The optical body is
The first optical layer has, in the width direction, a knurling portion at both ends, and a region in which a fine uneven shape is formed inside the knurling portion,
In the region where the fine concavo-convex shape is formed, the layer thickness distribution of the first optical layer becomes thicker from both ends in the width direction toward the center, and the cross-sectional shape in the thickness direction has a convex shape. And the convex layer thickness distribution curve of the first optical layer is an optical body in which at least one recessed region is formed.
An optical body manufacturing method characterized by the above.   Furthermore, the manufacturing method of the optical body of Claim 7 which has the slit and the punching process cut into the optical body of an embedded layer formation process, and an optical body of a standard dimension.