JP2023016387A - Method for producing film with uneven structure and method for producing functional film - Google Patents

Abstract

To provide a method for producing a film with an uneven structure, which is capable of suppressing insertion of bubbles when a mold is used and a transparent resin layer having an appropriate thickness and an uneven structure is formed on a surface.SOLUTION: There is provided a method for producing a film with an uneven structure in which the uneven structure is provided on a surface. The method for producing a film with an uneven structure is configured to: form a curable resin layer by applying a coating liquid containing a curable resin and having a viscosity of 500 to 100,000 mPa s at 25°C to a surface of a mold having an uneven structure on the surface, and by laminating a base material on the coating liquid; form a transparent resin layer having a maximum thickness of 30 to 400 μm on which the uneven structure of the mold is transferred by curing the curable resin layer; and separate the transparent resin layer and the mold.SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to a method for producing a film with an uneven structure and a method for producing a functional film.

2. Description of the Related Art As a functional film such as an image display film, for example, a film having a reflective film having a fine uneven structure is known. Such a functional film is produced by forming a reflective film on the surface of a transparent resin layer having a corresponding concave-convex structure on the surface.

An imprint method is known as a method for simply manufacturing a transparent resin layer having an uneven structure on its surface. In the imprint method, a material to be transferred containing a curable resin is placed on the surface of a base material, a mold having an uneven structure on the surface is pressed against the material to be transferred, and the material to be transferred is cured to form the uneven structure of the mold. A transparent resin layer (cured material layer) transferred to the surface is formed on the surface of the substrate.

However, in the above imprinting method, when the mold is pressed against the material to be transferred, there is a phenomenon that air bubbles remain between the mold and the material to be transferred or inside the material to be transferred (hereinafter also referred to as "bubble entrapment"). can occur. If bubble entrainment occurs, there is a risk that the accuracy of the concave-convex structure will decrease, and that the optical performance will decrease due to the scattering of light originating from the bubbles.
Therefore, in order to remove air bubbles between the mold and the material to be transferred, it has been studied to use the concave-convex structure of the mold as bubble removal grooves (Patent Document 1).

JP 2017-009634 A

However, when the concave-convex structure of the mold is used as bubble vent grooves, there is a possibility that desired optical characteristics cannot be obtained depending on the structure.
From the viewpoint of the flatness and mechanical strength of the transparent resin layer, it is desirable to keep the thickness of the transparent resin layer at an appropriate level. In order to form a transparent resin layer with an appropriate thickness, it is desirable to increase the viscosity of the coating liquid to some extent. However, when the viscosity of the coating liquid increases, it becomes difficult for air bubbles to escape, and bubble entrapment tends to occur.

The present invention relates to a method for producing a film with an uneven structure that can suppress entrapment of bubbles when forming a transparent resin layer having an uneven structure on the surface and an appropriate thickness using a mold, and a functional film using the same. A manufacturing method is provided.

The present invention has the following aspects.
<1> A method for producing a film having an uneven structure, which has a transparent resin layer having an uneven structure on its surface, and the transparent resin layer has a maximum thickness of 30 to 400 μm,
A coating liquid containing a curable resin and having a viscosity of 500 to 100,000 mPa·s at 25° C. is applied to the surface of the mold having an uneven structure corresponding to the uneven structure of the transparent resin layer, and Laminating a base material to form a curable resin layer,
curing the curable resin layer to form the transparent resin layer;
separating the transparent resin layer and the mold;
A method for producing a film with an uneven structure.
<2> The manufacturing method according to <1>, wherein the concave-convex structure of the transparent resin layer includes a plurality of concave portions, a plurality of convex portions, or a plurality of convex portions and concave portions.
<3> The method according to <1> or <2>, wherein the concave-convex structure of the transparent resin layer includes cylindrical, conical, truncated conical, hemispherical, prismatic, pyramidal or truncated pyramidal protrusions. .
<4> The uneven structure of the transparent resin layer includes first grooves extending in a direction substantially parallel to the first direction of the transparent resin layer and second grooves extending in a direction substantially perpendicular to the first direction of the transparent resin layer. The manufacturing method of <1> or <2> above, wherein the two-dimensional pattern shape includes grooves.
<5> The manufacturing method according to <1> or <2>, wherein the concave-convex structure of the transparent resin layer has a stripe pattern shape including grooves extending in a direction substantially perpendicular to the first direction of the transparent resin layer.
<6> A method for producing a functional film, comprising producing a film with an uneven structure by the production method according to any one of <1> to <5>.
<7> The method for producing a functional film according to <6>, wherein a reflective film is formed on the uneven structure of the transparent layer of the film with the uneven structure.

According to the method for producing a film with an uneven structure of the present invention, it is possible to suppress entrapment of bubbles when forming a transparent resin layer having an uneven structure on the surface and an appropriate thickness using a mold.

It is a schematic cross section showing an example of a film with a concavo-convex structure. It is a schematic top view which shows an example of the uneven|corrugated structure of a transparent resin layer. FIG. 5 is a schematic top view showing another example of the concave-convex structure of the transparent resin layer. FIG. 5 is a schematic top view showing another example of the concave-convex structure of the transparent resin layer. It is a schematic cross section which shows an example of the manufacturing method of the film with uneven|corrugated structure. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic cross-sectional view showing an example of a reflective image display film, which is a first embodiment of a functional film;

The meanings and definitions of the terms used in the present invention are as follows.
The “concavo-convex structure” means a concavo-convex shape composed of a plurality of convex portions, a plurality of concave portions, or a plurality of convex portions and concave portions.
"MD" means Machine Direction.
"(Meth)acrylate" means acrylate or methacrylate.
A "film" may be a sheet or a continuous band.
In the present specification and claims, "-" indicating a numerical range means that the numerical values described before and after it are included as lower and upper limits.
"Viscosity" is measured by, for example, an E-type viscometer. Specifically, the viscosity is determined by measuring the torque (shear stress) acting on the cylindrical surface when a cylindrical rotor is placed in the sample and rotated at a constant speed. The rotation speed of the rotor is assumed to be 100 [1/s].
"Total light transmittance" is measured according to JIS K 7361:1997 (ISO13468-1:1996).
The dimensional ratios in FIGS. 1 to 6 are different from the actual ones for convenience of explanation.

<Film with uneven structure>
A film with a textured structure manufactured by the method for manufacturing a film with a textured structure of the present invention has a transparent resin layer having a textured structure on its surface.
The transparent resin layer may be provided on the substrate.

FIG. 1 is a cross-sectional view showing an example of a film with a concavo-convex structure.
The film with an uneven structure of this example has a substrate 1 and a transparent resin layer 3 having an uneven structure on its surface provided on the substrate 1 . The transparent resin layer 3 is positioned as the outermost layer of the film with the uneven structure.

Materials for the substrate include, for example, polyester (polyethylene terephthalate (hereinafter also referred to as “PET”), polyethylene naphthalate, etc.), polypropylene, polymethyl methacrylate, polycarbonate, triacetyl cellulose, polyvinyl alcohol, polyether ether ketone, A cycloolefin polymer (hereinafter also referred to as "COP") can be mentioned.
The substrate may have a single layer structure or a multilayer structure.
A transparent film is usually used as the substrate. As the transparent film, a stretched film is preferable, and a biaxially stretched film is more preferable, from the viewpoint of having mechanical strength.
The thickness of the substrate is, for example, 20-300 μm. By setting the thickness of the base material within this range, the rigidity of the base material can be maintained, and bending and buckling of the film can be suppressed. As a result, the flatness and mechanical strength of the transparent resin layer can be secured.

The transparent resin layer contains a transparent resin as a main component.
The expression "mainly composed of a transparent resin" means that the transparent resin accounts for 80% by mass or more of the total mass of the transparent resin layer. The ratio of the transparent resin to the total mass of the transparent resin layer is preferably 90% by mass or more, and may be 100% by mass.

The transparent resin includes a cured product of a curable resin. The curable resin will be described later in detail.
The transparent resin may further contain a transparent resin other than the cured product of the curable resin.
Other transparent resins include, for example, thermoplastic resins. Examples of thermoplastic resins include polyesters (polyethylene terephthalate (hereinafter also referred to as “PET”), polyethylene naphthalate, etc.), acrylic resins, polyolefins, cycloolefin polymers (hereinafter also referred to as “COP”), polycarbonates, Polyimide, urethane resin, ionomer, polyvinyl acetal resin (polyvinyl butyral (hereinafter also referred to as "PVB"), ethylene-vinyl acetate copolymer (hereinafter also referred to as "EVA"), fluororesin, silicone resin is mentioned.
The ratio of the cured product of the curable resin to the total mass of the transparent resin is preferably 10% by mass or more, more preferably 20% by mass or more, and may be 100% by mass.

The transparent resin layer may contain components other than the transparent resin (hereinafter also referred to as "optional components"), if necessary. Examples of optional components include organic materials and inorganic materials other than transparent resins. Examples of inorganic materials include metals, metal oxides, glass, quartz, ceramics, and carbon-based materials (carbon black, etc.).

The transparent resin layer has an uneven structure on its surface.
The relief structure typically includes a plurality of protrusions, a plurality of recesses, or a plurality of protrusions and recesses.
Examples of the convex portions include elongated ridges extending on the surface of the transparent resin layer, projections scattered on the surface of the transparent resin layer, and the like.
Examples of the concave portion include long grooves extending on the surface of the transparent resin layer and holes scattered in the transparent resin layer.

Examples of the shape of the ridges or grooves include straight lines, curved lines, bent shapes, and the like. A plurality of ridges or grooves may exist in parallel to form stripes.
The cross-sectional shape of the ridges or grooves in the direction orthogonal to the longitudinal direction may be rectangular, trapezoidal, triangular, semicircular, or the like.
The shape of the protrusions or holes may be cylindrical, conical, truncated cone, hemispherical, prismatic (triangular prismatic, square prismatic, hexagonal prismatic, etc.), pyramidal (triangular pyramidal, square pyramidal, hexagonal pyramidal, etc.). ), truncated pyramid (quadrangular truncated pyramid, hexagonal truncated pyramid, etc.), polyhedron, and the like. From the standpoint of ease of mold production, a cylindrical shape, a conical shape, a truncated conical shape, a hemispherical shape, a prismatic shape, a pyramidal shape, or a truncated pyramidal shape is preferable.

The width of the ridges or grooves is preferably 1 nm to 1000 μm, more preferably 10 nm to 1000 μm, even more preferably 15 nm to 300 μm. The width of the ridge means the length of the base in a cross section perpendicular to the longitudinal direction. The width of the groove means the length of the upper side in a cross section perpendicular to the longitudinal direction.

The width of the projections or holes is preferably 1 nm to 1000 μm, more preferably 10 nm to 1000 μm, even more preferably 15 nm to 300 μm. The width of the projection means the length of the base in a cross section perpendicular to the longitudinal direction when the bottom is elongated, and otherwise means the maximum length of the bottom of the projection. The width of the hole means the length of the upper side in a cross section perpendicular to the longitudinal direction when the opening is elongated, and otherwise means the maximum length of the opening of the hole.

The height of the uneven structure (height of protrusions, depth of recesses) is preferably 1 nm to 1000 μm, more preferably 10 nm to 1000 μm, even more preferably 15 nm to 800 μm.

In a region where a plurality of protrusions (or a plurality of recesses) are densely packed, the pitch (center-to-center distance) between adjacent protrusions (or adjacent recesses) is preferably 1000 μm or less, more preferably 10 nm to 1000 μm, 50 nm to 1000 μm is more preferable, and 50 nm to 300 μm is particularly preferable. At this time, the pitch between adjacent protrusions (or adjacent recesses) may be regular, or at least partially irregular.

The concave-convex structure of the transparent resin layer can include a plurality of independent protrusions.
In the case of forming a transparent resin layer having an uneven structure including a plurality of independent protrusions on its surface, a mold for forming this transparent resin layer has an uneven structure including a plurality of mutually independent holes on its surface. Since these holes are independent of each other, when the mold is pressed against the curable resin layer, air bubbles in the concave portions are difficult to escape, and bubble entrapment is likely to occur. In the present invention, even when such a mold is used, bubble entrapment can be suppressed, and the usefulness of the present invention is high.

FIG. 2 shows an example of the uneven structure of the transparent resin layer. The uneven structure of this example includes a plurality of protrusions 31 scattered on the surface of the transparent resin layer.
Although an example in which the projection 31 is circular in top view is shown here, the shape of the projection 31 is not limited to the illustrated example. The shape of the protrusion 31 may be the same as described above, and may be cylindrical, conical, hemispherical, or prismatic, for example.

FIG. 3 shows another example of the concave-convex structure of the transparent resin layer. The uneven structure of this example includes first grooves 33 extending in a direction substantially parallel to the first direction of the transparent resin layer and second grooves extending in a direction (second direction) substantially perpendicular to the first direction of the transparent resin layer. It is a two-dimensional pattern shape including grooves 35 . In the two-dimensional pattern shape of FIG. 3, a plurality of first grooves 33 and a plurality of second grooves 35 are formed. Each of the plurality of first grooves 33 is formed from one end to the other end in the first direction of the transparent resin layer. Each of the plurality of second grooves 35 connects adjacent first grooves 33 . A plurality of regions 37 partitioned from each other by a plurality of first grooves 33 and a plurality of second grooves 35 are formed. A plurality of regions 37 are independent of each other. The height of each of the plurality of regions 37 may be uniform or at least partially non-uniform. An example in which at least a portion of the height of the region 37 is non-uniform is an example in which the region 37 has an inclination in the height direction.
The pitches of the plurality of first grooves 33 and the plurality of second grooves 35 may be regular or at least partially irregular. In the example shown in FIG. 2, at least part of the pitch of each of the first grooves 33 and the second grooves 35 is irregular. In the first direction, the position of the second groove 35 extending from any one first groove 33 (hereinafter, also referred to as groove 33a for convenience) to one end side in the second direction, and the position of the second groove 35 in the second direction It is different from the position of the second groove 35 extending on the end side. At least part of the regions 37 adjacent to each other via the groove 33a have different center positions (black circle positions in the figure) in the first direction when viewed from above. The depths of the first grooves 33 and the second grooves 35 may be uniform, or at least partially may be non-uniform.
In a two-dimensional pattern shape, the first direction is typically MD. Such a two-dimensional pattern shape is preferable when producing a functional film by a roll-to-roll method.

FIG. 4 shows another example of the concave-convex structure of the transparent resin layer. The concave-convex structure of this example has a stripe pattern shape including grooves 39 extending in a direction substantially perpendicular to the first direction of the transparent resin layer.
A plurality of grooves 39 are formed in the stripe pattern shape of FIG. The pitch of the plurality of grooves 39 may be regular or at least partially irregular. The depths of the plurality of grooves 39 may be uniform, or at least some of them may be non-uniform.
In the stripe pattern shape, the first direction is typically MD. Similar to the two-dimensional pattern shape, such a stripe pattern shape is preferable when producing a functional film by a roll-to-roll method. When the first direction is the MD, the grooves are preferably quadrangular prism-shaped or sawtooth-shaped grooves having surfaces substantially perpendicular to the MD. In the conventional method, air bubbles tend to accumulate on the surface perpendicular to the MD, and the usefulness of the present invention is high.

When the concave-convex structure of the mold for forming the concave-convex structure has a surface substantially perpendicular to the roll-to-roll flow direction (MD), a curable resin layer is formed on the substrate, and the mold is pressed against the curable resin layer. In the conventional method, air bubbles tend to accumulate in this portion of the surface, and bubble entrapment tends to occur.
In the present invention, bubble entrainment can be suppressed even when such a mold is used, so the present invention is highly useful when such a mold is used.
Examples of the concave-convex structure of the mold having a surface substantially perpendicular to the MD include the concave-convex structure corresponding to the concave-convex structure shown in FIG. Examples include those corresponding to the uneven structure whose direction is the MD, and those corresponding to the uneven structure shown in FIG. 4 whose first direction is the MD.

The maximum thickness of the transparent resin layer is 30-400 μm, preferably 50-350 μm, more preferably 100-350 μm.
Here, the maximum thickness of the transparent resin layer refers to the distance from the highest position of the uneven structure on the surface of the transparent resin layer to the substrate when the transparent resin layer side in the thickness direction of the film with the uneven structure is the upper side. It refers to the shortest distance to the interface (smooth surface).
The thicker the maximum thickness of the transparent resin layer, the more easily bubble entrapment tends to occur. In the conventional method of forming a curable resin layer on a substrate and pressing a mold against the curable resin layer, if the maximum thickness of the transparent resin layer is 30 μm or more, entrapment of bubbles is likely to occur.
In the present invention, since the curable resin layer is formed on the mold, even if the maximum thickness of the transparent resin layer is as thick as 30 μm or more, it is possible to suppress entrapment of bubbles. Further, when the maximum thickness of the transparent resin layer is 30 to 400 μm, the flatness of the transparent resin layer can be maintained.

The total light transmittance of the transparent resin layer is preferably 70% or higher, more preferably 80% or higher, even more preferably 90% or higher. When the total light transmittance is at least the above lower limit, the film with a concave-convex structure and the functional film using the same have excellent transparency and background visibility.

<Method for producing film with uneven structure>
The method for producing a film with a concave-convex structure of the present invention has the following steps (a) to (c).
Step (a): As shown in FIG. 5, a specific coating liquid is applied to the surface of a mold M having an uneven structure corresponding to the uneven structure of the transparent resin layer 3 to be formed, and a base material is applied thereon. 1 to form a curable resin layer 2;
Step (b): As shown in FIG. 5, the step of curing the curable resin layer 2 to form the transparent resin layer 3 .
Step (c): A step of separating the transparent resin layer 3 and the mold M, as shown in FIG.

(mold)
As the mold, for example, a resin film having an uneven structure formed on its surface is preferable. If the mold is a resin film, a series of steps from step (a) to step (c) can be carried out by a roll-to-roll method, resulting in excellent productivity of the film with an uneven structure. A resin film having an uneven structure formed on its surface can be produced, for example, by sandwiching a resin material between a master mold and a substrate film, transferring the uneven pattern of the master mold to the resin material, and solidifying the resin material.

The concave-convex structure of the mold has a shape corresponding to the concave-convex structure of the transparent resin layer 3 to be formed. Typically, the concave-convex structure of the transparent resin layer 3 is reversed. For example, when the concave-convex structure of the transparent resin layer 3 includes a plurality of protrusions, the concave-convex structure of the mold includes a plurality of holes, and the shape and width of each of the plurality of holes and their positions correspond to the shape and width of the plurality of protrusions. and their positions. When the concave-convex structure of the transparent resin layer 3 is a two-dimensional pattern shape including first grooves extending in a direction substantially parallel to the first direction and second grooves extending in a direction substantially perpendicular to the first direction, The concave-convex structure of the mold has a two-dimensional pattern shape including first ridges extending in a direction substantially parallel to the first direction and second ridges extending in a direction substantially perpendicular to the first direction. The shape and width of each of the ridges and the second ridges and their positions are the same as those of the first groove and the second groove. When the concave-convex structure of the transparent resin layer 3 has a striped pattern shape including grooves extending in a direction substantially perpendicular to the first direction, the concave-convex structure of the mold is a stripe including ridges extending in a direction substantially perpendicular to the first direction. It has a pattern shape, and the shape and width of the ridges are the same as those of the first groove and the second groove.

(Coating liquid)
The coating liquid contains a curable resin.
Examples of curable resins include photocurable resins (acrylic resins, epoxy resins, etc.) and thermosetting resins (acrylic resins, epoxy resins, etc.).
As the curable resin, a photocurable resin is preferable because it can be cured by irradiation with light such as ultraviolet (UV) light, and a photocurable acrylic resin is more preferable from the viewpoint of transparency.

A photocurable acrylic resin contains (meth)acrylate.
(Meth)acrylates include, for example, (meth)acrylate monomers and (meth)acrylate oligomers.

(Meth)acrylate monomers include, for example, monofunctional (meth)acrylate monomers and polyfunctional (meth)acrylate monomers.
Monofunctional (meth)acrylate monomers include, for example, isobornyl (meth)acrylate.
Polyfunctional (meth)acrylate monomers include, for example, tricyclodecanedimethanol di(meth)acrylate, neopentylglycol hydroxypivalate di(meth)acrylate, 9,9-bis[4-(2-hydroxyethoxy)phenyl] fluorene (meth)acrylate and dipentaerythritol hexa(meth)acrylate.

(Meth)acrylate oligomers include, for example, poly(meth)acrylates of polyether polyols, poly(meth)acrylates of polyester polyols, and urethane (meth)acrylates.
Examples of polyether polyols include polyoxyalkylene polyols such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.
Examples of polyester polyols include caprolactone-modified dipentaerythritol and caprolactone-modified neopentyl glycol hydroxypivalate.
The (meth)acrylate oligomer has a number average molecular weight of, for example, 300 to 10,000. The number average molecular weight of the (meth)acrylate oligomer is the polystyrene equivalent number average molecular weight obtained by gel permeation chromatography (GPC) measurement. If a peak of unreacted low-molecular-weight components (monomers, etc.) appears in the GPC measurement, the number-average molecular weight is obtained by excluding the peak.
One or two or more (meth)acrylates constituting the photocurable acrylic resin may be used.

The photocurable acrylic resin preferably contains a (meth)acrylate having a (meth)acrylic equivalent of 200 g/eq or more (hereinafter also referred to as "(meth)acrylate a"). By including (meth)acrylate a, the proportion of reaction sites in the photocurable acrylic resin is reduced, shrinkage during curing is suppressed, and curling of the film with the uneven structure is suppressed. In addition, the elastic modulus of the transparent resin layer is lowered, and the cutability of the functional film is improved. The (meth)acrylic equivalent of (meth)acrylate a is preferably 270 g/eq or more, more preferably 320 g/eq or more.
Although the upper limit of the (meth)acrylic equivalent of (meth)acrylate a is not particularly limited, it is, for example, 20000 g/eq.
The (meth)acrylic equivalent is the value obtained by dividing the molecular weight of (meth)acrylate by the number of (meth)acryloyl groups. The molecular weight of (meth)acrylate is the value of the number average molecular weight obtained by GPC measurement for compounds whose molecular weight distribution can be obtained by GPC measurement, and the compound whose molecular weight distribution is not obtained by GPC measurement is calculated from the structural formula. is the formula weight to be used.

(Meth)acrylate a includes, for example, a bifunctional (meth)acrylate oligomer having a number average molecular weight of 540 or more (caprolactone-modified neopentyl glycol hydroxypivalate di(meth)acrylate, etc.), a hexafunctional (Meth)acrylate oligomers (caprolactone-modified dipentaerythritol hexaacrylate, etc.).

As the (meth)acrylate a, a polyfunctional (meth)acrylate is preferred. By using polyfunctional (meth)acrylate, the elastic modulus of the transparent resin layer can be increased.
Among polyfunctional (meth)acrylates, (meth)acrylate oligomers are preferred. The CTE of the transparent resin layer can be increased by using the (meth)acrylate oligomer. Moreover, the viscosity of the coating liquid for forming the transparent resin layer can be increased, and the thickness of the transparent resin layer can be easily increased.

The photocurable acrylic resin may further contain (meth)acrylates other than (meth)acrylate a.
As other (meth)acrylates, polyfunctional (meth)acrylate monomers (hereinafter also referred to as “(meth)acrylate b”) having a (meth)acrylic equivalent of less than 200 g/eq are preferred. By including (meth)acrylate b in the photocurable acrylic resin, the strength of the cured film (transparent resin layer) can be improved. Moreover, the viscosity of the coating liquid for forming the transparent resin layer can be lowered, and the coatability is improved.
As the (meth)acrylate b, a polyfunctional (meth)acrylate monomer containing an alicyclic structure, such as tricyclodecanedimethanol di(meth)acrylate, is preferable from the viewpoint of increasing the refractive index of the transparent resin layer.

The photocurable acrylic resin is used as another (meth)acrylate for the purpose of adjusting the mechanical properties and adhesion of the resin after curing. ) acrylate (hereinafter also referred to as “(meth)acrylate c”).

The ratio of (meth)acrylate a to the total mass of the photocurable acrylic resin is preferably 20% by mass or more, more preferably 40% by mass or more, and even more preferably 50% by mass or more. When the ratio of (meth)acrylate a is at least the above lower limit, the effect of suppressing the occurrence of curling and the effect of improving the cutting workability are likely to be obtained.
The proportion of the (meth)acrylate a may be 100% by mass, but when the photocurable acrylic resin contains other (meth)acrylates, it is preferably 95% by mass or less, more preferably 90% by mass or less. It is preferably 80% by mass or less, and more preferably 80% by mass or less.

The ratio of (meth)acrylate b to the total mass of the photocurable acrylic resin is preferably 5 to 60% by mass, more preferably 10 to 50% by mass, even more preferably 20 to 40% by mass. If the proportion of (meth)acrylate b is at least the above lower limit value, the strength of the transparent resin layer can be increased, and if it is at most the above upper limit value, the viscosity of the coating liquid for forming the transparent resin layer can be increased. Easy to thicken.

When the curable resin is a photocurable resin, the coating liquid may contain a photopolymerization initiator.
Examples of photopolymerization initiators include alkylphenone-based photopolymerization initiators, acylphosphine oxide-based photopolymerization initiators, titanocene-based photopolymerization initiators, oxime ester-based photopolymerization initiators, oxyphenyl acetate-based photopolymerization initiators, and benzoin. photoinitiator, benzophenone photoinitiator, thioxanthone photoinitiator, benzyl-(o-ethoxycarbonyl)-α-monoxime, glyoxyester, 3-ketocoumarin, 2-ethylanthraquinone, camphorquinone, tetramethylthiuram sulfide, azobisisobutyronitrile, benzoyl peroxide, dialkyl peroxide, tert-butyl peroxypivalate and the like. One of these photopolymerization initiators may be used alone, or two or more thereof may be used in combination.
The content of the photopolymerization initiator is, for example, 0.05 to 10 parts by mass with respect to 100 parts by mass of the photocurable resin.

The coating liquid may contain the optional components described above, if necessary.
The content of the optional component is preferably set so that the ratio of the transparent resin to the total mass of the transparent resin layer is 80% by mass or more.

The coating liquid may optionally contain a non-reactive diluent for the purpose of adjusting the viscosity of the coating liquid. Non-reactive diluents include compounds that do not react with the curable resin, are liquid at 25° C., and are removable from the coating by drying, such as esters (butyl acetate, ethyl acetate, isobutyl acetate, acetic acid propyl, neopentyl acetate, ethyl lactate, propylene glycol monomethyl ether acetate, etc.), ketones (acetone, cyclohexanone, etc.), ethers (tetrahydrofuran, etc.), alcohols (isopropyl alcohol, methanol, ethanol, butanol, etc.), N,N-dimethylacetamide , N,N-dimethylformamide, N-methyl-2-pyrrolidone, and toluene. These non-reactive diluents may be used singly or in combination of two or more.
The content of the non-reactive diluent can be appropriately set in consideration of the viscosity of the coating liquid, and is, for example, 0 to 80% by mass with respect to the total mass of the coating liquid.

The viscosity of the coating liquid at 25° C. is 500 to 100,000 mPa·s, preferably 1000 to 50,000 mPa·s. If the viscosity of the coating liquid is at least the above lower limit, the maximum thickness of the curable resin layer, and thus the maximum thickness of the transparent resin layer, can easily be 30 μm or more.
The higher the viscosity of the coating liquid, the higher the viscosity of the curable resin layer. In the conventional method of forming a curable resin layer on a base material and pressing a mold against the curable resin layer, if the viscosity of the coating liquid is 500 mPa·s or more, entrapment of bubbles is likely to occur.
In the present invention, since a curable resin layer is formed on the mold, even if the viscosity of the coating liquid is as high as 500 to 100,000 mPa·s, entrapment of bubbles can be suppressed.

(Step (a))
Examples of methods for applying the coating liquid include die coating, blade coating, gravure coating, ink jet, and spray coating.

If desired, the non-reactive diluent is removed after application of the coating solution and prior to lamination of the substrate.
Examples of the method for removing the non-reactive diluent include a method by heating, a method of removing under reduced pressure, and the like, and a method by heating is preferred. The heating temperature is preferably 40 to 140°C, more preferably 40 to 120°C.

As a method for laminating the substrate, a known wet lamination method can be applied. For example, there is a method in which the base material is placed on the coating surface of the mold coated with the coating liquid, and the base material is moved between a pair of rollers to be pressure-bonded. When laminating the substrates, a cotter as described in JP-A-2010-131643 may be used for positioning, if necessary.
The temperature during lamination is preferably 20 to 100.degree. C., more preferably 20 to 80.degree.
By heating during lamination, the viscosity of the resin can be reduced.
The pressure during crimping is, for example, 0.01 MPa to 3 MPa. When the pressure is equal to or higher than the lower limit, air bubbles are less likely to enter, and when the pressure is equal to or lower than the upper limit, excessive stretching of the curable resin layer can be suppressed.
The moving speed of the substrate is, for example, 1 m/min to 100 m/min. If the moving speed is equal to or higher than the lower limit, the productivity is excellent, and if the moving speed is equal to or lower than the upper limit, air bubbles tend to be difficult to mix.

(Curable resin layer)
The maximum thickness of the curable resin layer is 30-400 μm, preferably 50-350 μm, more preferably 100-350 μm.
The thicker the maximum thickness of the curable resin layer, the more likely it is that bubbles will be trapped. In the conventional method of forming a curable resin layer on a base material and pressing a mold against the curable resin layer, if the maximum thickness of the curable resin layer is 30 μm or more, entrapment of bubbles is likely to occur.
In the present invention, since the curable resin layer is formed on the mold, even if the maximum thickness of the curable resin layer is as thick as 30 μm or more, it is possible to suppress entrapment of bubbles. Further, when the maximum thickness of the transparent resin layer is 30 to 400 μm, the flatness of the curable resin layer and thus the transparent resin layer can be maintained.

(Step (b))
When the curable resin is a thermosetting resin, the curable resin layer can be cured by heating the curable resin layer.
When the curable resin is a photocurable resin, the curable resin layer can be cured by irradiating the curable resin layer with light.
The method of irradiating light includes a method of irradiating light from the mold side using a mold made of a translucent material, a method of irradiating light from the substrate side using a substrate made of a translucent material, and a method of irradiating light from the substrate side using a mold made of a translucent material. A method of irradiation can be mentioned. The wavelength of light is preferably 200-400 nm. When irradiating with light, the curable resin layer may be heated to promote curing.
The temperature for light irradiation is preferably 20 to 40°C, more preferably 25 to 35°C.

(Step (c))
The temperature at which the transparent resin layer and the mold are separated is preferably 20 to 100.degree. C., more preferably 20 to 80.degree.
After step (c), the transparent resin layer and the substrate may be separated, if necessary.

The resulting film with an uneven structure is used, for example, in the production of functional films (transmissive image display films, heat ray reflective films, design films, mirror films, soundproof films, radio wave control films, lenticular films, etc.) to be described later. be done. However, the use of the film with an uneven structure is not limited to this, and it can be used for other uses.

(Mechanism of action)
In the above-described method for producing a film with an uneven structure, the coating liquid for forming the curable resin layer is applied to the surface of the mold rather than the base material. Although it is thick, it can suppress bubble entrapment.
Suppression of bubble inclusion improves the accuracy of the concave-convex structure of the transparent resin layer, suppresses scattering due to bubbles, and improves the optical properties of the film with the concave-convex structure.
Moreover, since the coating liquid can be made highly viscous, it is easy to thicken the transparent resin layer.
When the transparent resin layer has an appropriate thickness, the flatness of the transparent resin layer can be maintained and the mechanical strength is improved. As a result, it becomes easier to obtain a self-supporting film. In addition, shrinkage of the transparent resin layer and accompanying wrinkles and bubbles can be suppressed when producing a functional laminated glass to be described later.

<Functional film>
Examples of the functional film provided with a film with an uneven structure obtained by the method for producing a film with an uneven structure of the present invention include those having one or more transparent resin layers having an uneven structure on the surface and a reflective film. be done.

The transparent resin layer is as described above.
A reflective film is a film that partially reflects and partially transmits incident light. A reflective film is used for the purpose of imparting functionality to the functional film. Functions imparted by the reflective film include, for example, image display function, heat ray reflecting function, designability, dimming function, and mirror function. The reflective film will be described later in detail.

The thickness of the functional film varies depending on the function of the functional film, but is preferably 10-1000 μm, more preferably 100-500 μm, and even more preferably 200-400 μm. If the thickness of the functional film is at least the above lower limit, the functional film will have excellent mechanical strength, and if it is at most the above upper limit, the functional film will be excellent in cutability.

The total light transmittance of the functional film is preferably 5-90%. When the total light transmittance is at least the above lower limit, the transparency of the functional film and the visibility of the background are excellent. The total light transmittance is preferably 10% or higher, more preferably 15% or higher, even more preferably 50% or higher. On the other hand, if the total light transmittance is equal to or less than the above upper limit, the function of the functional film can be appropriately expressed.
The total light transmittance of the functional film can be adjusted by adjusting the ratio of the transparent resin to the total mass of the functional film, the material constituting the reflective film, the film thickness, and the like.

From the viewpoint of the transparency of the functional film, the ratio of the transparent resin to the total mass of the functional film is preferably 90% by mass or more, preferably 95% by mass or more.
The upper limit of the ratio of the transparent resin to the total mass of the functional film varies depending on the function of the functional film, but is, for example, 99.9% by mass.

As the form of the functional film, one having one or more transparent resin layers and a reflective film is preferable. A heat ray reflective film with a design layer having a reflective film, a mirror film having a half mirror layer with a reflective film, a reflective film on the surface of the void structure embedded in the transparent resin layer Examples include a soundproof film having a soundproof layer and a radio wave control film having a radio wave control layer having a reflective film such as ITO on a transparent resin layer. It may also be a lenticular film having lenticular lenses on the surface of one or more transparent resin layers.

The image display film is a film that allows the viewer to see through the film and displays image light projected onto the film in a visually recognizable form as an image. Specifically, it is a film having a first surface and a second surface on the opposite side, and transmits a scene on the first surface side so as to be visible to an observer on the second surface side. The spectacle on the side of the second surface is transmitted so as to be visible to the observer on the side of the first surface, and the image light projected from the projector installed on the side of the first surface is transmitted to the observer on the side of the first surface. and a film that is visually recognizable as an image to either one of the observers on the second surface side.
The image display film may be a reflective image display film that visibly displays image light projected from the first surface side as an image to an observer on the first surface side. It may also be a transmissive image display film that visibly displays image light projected from the side as an image to an observer on the second surface side.

Here, the "first surface" means the outermost surface of the image display film (or a transparent screen to be described later), which is the surface on which image light is projected from the projector.
"Second surface" means the outermost surface of the image display film (or transparent screen), which is opposite to the first surface.
The term “scene on the first surface side (second surface side)” refers to an image viewed from an observer on the second surface side (first surface side) of the image display film (or transparent screen). It means the image seen beyond the display film (or transparent screen). A scene does not include an image displayed by forming an image on an image display film (or a transparent screen) with image light projected from a projector.

Examples of the image display layer provided with a reflective film include a light scattering layer in which a reflective film having an uneven structure is embedded in a transparent resin layer.
Examples of the heat ray reflective layer having a reflective film include a layer in which a high refractive index layer and a low refractive index layer are alternately laminated on a transparent resin layer.
Examples of the design layer provided with a reflective film include a printed layer formed by printing an ink for forming a reflective film with an arbitrary design on a transparent resin layer.
Examples of the mirror layer having a reflective film include a mirror layer in which a half-mirror layer, that is, a reflective film that partially reflects and partially transmits incident light is laminated on a transparent resin layer.
Also, the functional layer provided with the reflective film may include two or more of the above functional layers.
Note that the functional film may not have a reflective film. For example, it may be a lenticular sheet having lenticular lenses on the surface of a transparent resin layer.
The functional film may further include a protective layer and an ultraviolet absorbing layer. The protective layer is a layer provided on the outermost surface of the functional film to protect the surface of the functional layer and the surface of the transparent resin layer. Examples of the protective layer include a hard coat layer made of a cured product of a curable resin.
Embodiments of the functional film will be described below.

(Reflective image display film)
FIG. 6 is a cross-sectional view showing an example of a reflective image display film, which is the first embodiment of the functional film.
The reflective image display film 10 has a light scattering layer 11 (an image display layer having a reflective film).
The light scattering layer 11 has a reflective film 15 , a first transparent resin layer 13 positioned on one side of the reflective film 15 , and a second transparent resin layer 19 positioned on the other side of the reflective film 15 . .
The first transparent resin layer 13 has an uneven structure on the surface on the reflective film 15 side.
The reflective film 15 is provided along the surface of the first transparent resin layer 13 and has an uneven structure conformal to the uneven structure of the first transparent resin layer 13 .
The second transparent resin layer 19 has an uneven structure on the surface on the reflective film 15 side.

The first transparent resin layer 13 is the transparent resin layer of the above-described uneven structure film.
The uneven structure on the surface of the first transparent resin layer 13 is used for the purpose of imparting an uneven structure to the reflective film 15 .

The reflective film 15 may transmit part of the light incident on the reflective film 15 and reflect the other part. Reflective film 15 is typically composed of an inorganic material. Examples of inorganic materials include metals, metal oxides, and metal nitrides. Al, Ag, Cr, Mo, In, Ni, Ta, Ti, Cu, W etc. are mentioned as a metal. Examples of metals in metal oxides and metal nitrides include the same. The reflective film 15 may be a single layer film or a multilayer film.
Examples of the reflective film 15 include metal films, semiconductor films, dielectric single-layer films, dielectric multilayer films, and combinations thereof. Among them, a metal film or a metal oxide film containing at least one metal element selected from the group consisting of Al, Ag, Cr, Mo, In, Ni, Ta, Ti, Cu and W is preferable.

The reflective film 15 is formed along the surface of the first transparent resin layer 13 and has an uneven structure conformal to the uneven structure of the first transparent resin layer 13 . That is, the shape of the surface of the reflective film 15 on the side of the first transparent resin layer 13 and the side opposite to the first transparent resin layer 13 are the same as the shape of the surface of the first transparent resin layer 13 on the side of the reflective film 15 . It conforms and is substantially conformal to the uneven surface of the first transparent resin layer 13 .
The thickness of the reflective film 15 is, for example, 5 to 5000 nm. The thickness of the reflective film 15 can be calculated by observing the thickness of the portion having the maximum height of the projection from an electron microscope photograph of the cross section of the unevenness.

The second transparent resin layer 19, like the first transparent resin layer 13, contains a transparent resin as a main component.
Like the first transparent resin layer 13, the second transparent resin layer 19 may contain optional components.

Examples of the transparent resin in the second transparent resin layer 19 include a cured product of a curable resin and a thermoplastic resin. Examples of the curable resin and the thermoplastic resin are the same as those described above.
From the viewpoint of moldability, the transparent resin of the second transparent resin layer 19 preferably contains a cured product of a curable resin. As the curable resin, a photocurable resin is preferable from the viewpoint of being curable by irradiation with ultraviolet (UV) light, and a photocurable acrylic resin is more preferable from the viewpoint of transparency.

The second transparent resin layer 19 is formed so as to cover the surface of the reflective film 15, and the shape of the surface on the reflective film 15 side follows the shape of the surface of the reflective film 15 on the second transparent resin layer 19 side. are doing. The surface of the second transparent resin layer 19 opposite to the reflecting film 15 side is a smooth surface.
The maximum thickness of the second transparent resin layer 19 is, for example, 5 to 150 μm. Here, the maximum thickness of the second transparent resin layer 19 is the thickness of the second transparent resin layer 19 when the second transparent resin layer 19 side in the thickness direction of the reflective image display film 10 faces upward. The shortest distance from the lowest position of the concave-convex structure on the reflecting film 15 side of the second transparent resin layer 19 to the surface (smooth surface) of the second transparent resin layer 19 opposite to the reflecting film 15 side.

The thickness of the reflective image display film 10 is preferably 10 to 1000 μm, more preferably 15 to 500 μm, even more preferably 50 to 400 μm.

In addition, the functional film for which the film with the uneven structure obtained by the method for producing the film with the uneven structure of the present invention is used is not limited to the functional film of the illustrated embodiment.
For example, the functional film may be a transmissive image display film, a heat reflective film, a design film, a mirror film, a soundproof film, a radio wave control film, or a lenticular film.

The reflective image display film is not limited to the illustrated reflective image display film 10 .
For example, an adhesion layer may be provided between the reflective film 15 and the second transparent resin layer 19 . If the reflective image display film 10 has an adhesion layer, the adhesion between the reflective film 15 and the second transparent resin layer 19 can be improved. Moreover, as a result of being able to alleviate the influence of volume shrinkage on the reflective film 15 when forming the second transparent resin layer 19 on the adhesion layer, cracking of the reflective film 15 can be suppressed, which is preferable.

Thermoplastic resins such as COP, acrylic resins, polyesters, urethane resins, polycarbonates, PVB, and EVA are preferable as materials for the adhesion layer. If the material of the adhesion layer is a thermoplastic resin, volume shrinkage during formation of the adhesion layer on the reflective film 15 can be reduced compared to a cured product of a curable resin, and cracking of the reflective film 15 can be suppressed. In addition, it is possible to more effectively reduce the influence of the volume shrinkage on the reflective film 15 when forming the second transparent resin layer 19 on the adhesion layer.
The thickness of the adhesion layer is, for example, 0.5 to 5 μm. The thickness of the adhesion layer is obtained by measuring the thickness of the portion having the minimum height of the concave portion of the adhesion layer on the reflective film 15 side with a film thickness meter.

<Method for producing functional film>
The functional film is produced, for example, by producing a film with an uneven structure by the method described above, and, if necessary, forming a reflective film on the uneven structure of the transparent resin layer of the obtained film with an uneven structure. can.
Hereinafter, an embodiment of a method for producing a functional film will be described with reference to the reflective image display film 10 described above as an example.

The reflective image display film 10 can be produced, for example, by a method including the following steps A1 to A8.
Step A1: A first coating liquid containing a curable resin and having a viscosity of 500 to 100,000 mPa s at 25 ° C. is applied to the surface of the mold having an uneven structure on the surface, and if necessary, non-reactive. removing the curable diluent and laminating a substrate thereon to form a first curable resin layer;
Step A2: A step of curing the first curable resin layer to form the first transparent resin layer 13 .
Step A3: A step of separating the first transparent resin layer 13 and the mold.
Step A4: A step of physically vapor-depositing a metal on the surface of the first transparent resin layer 13 to form a reflective film 15 made of a metal thin film.
Step A5: A second coating liquid containing a curable resin is applied to the surface of the reflective film 15, the non-reactive diluent is removed as necessary, a release film is laminated thereon, and the second curing is performed. forming a flexible resin layer;
Step A6: A step of curing the second curable resin layer to form the second transparent resin layer 19 .
Step A7: A step of peeling the release film from the surface of the second transparent resin layer 19 .
Step A8: A step of peeling the substrate from the first transparent resin layer 13 .

Step A1:
Step A1 is the same as step (a) described above.
The first coating liquid is the same as the coating liquid used in the method for producing a film with an uneven structure of the present invention.

Step A2:
Step A2 is the same as step (b) described above.

Step A3:
Step A3 is the same as step (c) described above.

Step A4:
Examples of physical vapor deposition include vacuum deposition and sputtering.

Step A5:
Step A5 is the same as step A1 except that the second coating liquid is used instead of the first coating liquid, and the release film is used instead of the substrate.
Examples of the second coating liquid include those similar to the first coating liquid. However, the viscosity at 25° C. of the second coating liquid may be outside the range of 500 to 100,000 mPa·s. The second coating liquid also preferably has a viscosity of 500 to 100,000 mPa·s at 25° C. in terms of making the second transparent resin layer thicker.

<Functional film with adhesive layer>
An adhesive layer may be laminated on either or both of one surface side and the other surface side of the functional film to form a functional film with an adhesive layer.
The functional film with an adhesive layer can be used, for example, for producing functional laminated glass described later.

The adhesive layer is used for bonding the transparent substrate and the functional film.
Examples of the adhesive layer include those made of a thermoplastic resin composition containing a thermoplastic resin as a main component. Examples of the thermoplastic resin used for the adhesive layer include thermoplastic resins conventionally used for this type of application. Examples of thermoplastic resins include polyvinyl acetal resins (PVB, etc.), polyvinyl chloride resins, saturated polyester resins, polyurethane resins, ethylene-vinyl acetate copolymer resins (EVA, etc.), ethylene-ethyl acrylate copolymers. Polymeric resins, ionomers (such as materials obtained by cross-linking ethylene-methacrylic acid copolymer molecules with metal ions), and COPs can be used. From the viewpoint of heat resistance and weather resistance, the adhesive layer preferably contains PVB or EVA.
When adhesive layers are laminated on both one side and the other side of the functional film, the material of each adhesive layer may be the same or different.
The thickness of the adhesive layer is, for example, 1 μm to 1 mm.

A functional film with an adhesive layer can be produced by a method of laminating a functional film and an intermediate film serving as an adhesive layer.
From the viewpoint of heat resistance and weather resistance, the intermediate film preferably contains PVB or EVA.
As the interlayer film, those used for manufacturing laminated glass are preferable because the stacking operation can be easily performed.

A functional film with an adhesive layer can also be produced by a transfer method. In the transfer method, for example, a functional film is formed on a substrate, an adhesive layer is laminated on the surface of the functional film opposite to the substrate side, and then the substrate is peeled off from the functional film to form an adhesive layer. Obtain a functional film with
For example, the reflective image display film 10 (light scattering layer 11) is formed on the substrate by the above steps A1 to A7, and an adhesive layer is formed on the surface of the reflective image display film 10 opposite to the substrate side. After laminating, the substrate is peeled off from the reflective image display film 10, whereby the adhesive layer-attached reflective image display film can be manufactured.

<Functional laminated glass>
Functional laminated glass is obtained by laminating a first transparent substrate, a first adhesive layer, a functional film, a second adhesive layer, and a second transparent substrate in this order.
That is, functional laminated glass is obtained by sandwiching a functional film between two transparent substrates. The transparent base material and the functional film are adhered by an adhesive layer.

Examples of materials for the transparent base material (first transparent base material, second transparent base material) include glass and transparent resin. The material of each transparent substrate may be the same or different.
Examples of glass constituting the transparent substrate include soda lime glass, alkali-free glass, borosilicate glass, and aluminosilicate glass. A transparent substrate made of glass may be subjected to chemical strengthening, physical strengthening, hard coating, or the like in order to improve durability.
Examples of the transparent resin that constitutes the transparent substrate include polycarbonate, polyester (PET, polyethylene naphthalate, etc.), triacetyl cellulose, COP, polymethyl methacrylate, and fluororesin.
The thickness of the transparent substrate is, for example, 0.2 to 10 mm.

The shape of the transparent substrate may be flat or curved. In the conventional technology, wrinkles are likely to occur in the functional film, and from the point of view of being excellent in the usefulness of the present invention, a shape having a curved surface is preferable.
When the transparent substrate has a curved surface, the surface of the transparent substrate may be entirely curved, or may be composed of a curved portion and a flat portion. When the entire surface is curved or has a plurality of curved portions, the curvature may be constant or may vary depending on the portion. Examples of transparent substrates having curved surfaces include curved shapes such that one surface is convex and the other surface is concave, as seen in applications such as windshields (windshields for automobiles, etc.). Note that the curved surface here is a macroscopic curved surface that can be ignored in an observation area observed with a laser microscope.
When the transparent base material has a curved surface, the radius of curvature R of the curved surface can be appropriately set according to the application and type of the transparent base material, and is not particularly limited.

The adhesive layers (first adhesive layer, second adhesive layer) are as described above, and preferred embodiments are also the same.

The functional laminated glass consists of a first transparent substrate, an intermediate film serving as a first adhesive layer, the functional film of the present invention, an intermediate film serving as a second adhesive layer, and a second transparent substrate in this order. It can be manufactured by a method of heating and bonding in a stacked state.
When the functional laminated glass has a large area, a plurality of functional films may be arranged along the surface direction when the functional film is placed on the interlayer.
Preferred aspects of the intermediate film are as described above.

The heating temperature for bonding is preferably 80 to 150.degree. C., more preferably 90 to 140.degree. When the heating temperature is equal to or higher than the lower limit of the above range, embossing of the intermediate film disappears and haze can be suppressed. When the heating temperature is equal to or lower than the upper limit of the above range, excessive shrinkage of the functional film and accompanying wrinkles and bubbles can be suppressed.
The heating time for bonding is preferably 30 to 90 minutes, more preferably 45 to 75 minutes. When the heating time is at least the lower limit of the above range, the embossing of the intermediate film disappears and the haze can be suppressed. If the heating time is equal to or less than the upper limit of the above range, productivity is high, which is economically preferable.

The laminate of the transparent base material, the intermediate film and the functional film is placed in a vacuum bag (rubber bag), vacuumed, pre-bonded in a hot air oven at a relatively low temperature, and then autoclaved. It may be transferred to a pressurized state and permanently adhered at a relatively high temperature.
The heating temperature for pre-bonding is preferably 80°C or higher and lower than 120°C. The heating time for pre-bonding is preferably 30 to 90 minutes.
The heating temperature for final bonding is preferably 100 to 150°C. The heating time for final bonding is preferably 30 to 120 minutes. The pressure for final bonding is preferably 0.6 to 2.0 MPa [abs].

Considering the above heating process, the functional film preferably has at least one resin layer having a glass transition temperature (Tg) of 140° C. or less in order to easily suppress wrinkles of the functional film. By including at least one resin layer having a Tg of 140° C. or lower, the stress caused by the CTE difference during heating can be alleviated. A resin layer having a Tg of 140° C. or lower includes, for example, an adhesion layer. Although the lower limit of the Tg of the resin layer having a Tg of 140°C or less is not particularly limited, it is, for example, 123°C. The Tg of the resin layer is the midpoint glass transition temperature determined by differential scanning calorimetry (DSC) according to JIS K 6240:2011 (corresponding international standard ISO 22768:2006).

When the functional film has at least one resin layer having a Tg of 140° C. or less, another resin layer in the functional film (for example, a resin layer other than the adhesion layer, i.e., the first transparent resin layer 13 and/or At least one of the second transparent resin layers 19) is preferably a resin layer having storage elastic modulus/loss elastic modulus≧1, that is, having no fluidity, in order to maintain flatness of the film during adhesion. .
At this time, it is preferable that the total thickness of the resin layers having no fluidity in the functional film is 50 μm to 300 μm, since the flatness of the film can be maintained while suppressing wrinkles of the functional film. In particular, it is preferable that the total thickness of the resin layer having no fluidity is 50 μm to 200 μm, because it facilitates the production of the functional film in the roll-to-roll process.

Examples of the form of functional laminated glass include a transparent screen in which an image display film is sandwiched between two transparent substrates with an adhesive layer interposed therebetween, and a heat reflective film sandwiched between two transparent substrates with an adhesive layer interposed therebetween. A heat reflective laminated glass and a design film sandwiched between substrates are sandwiched between two transparent substrates via an adhesive layer. A mirror laminated glass and a soundproof film sandwiched between transparent substrates are sandwiched between two transparent substrates via an adhesive layer. A radio-controlled laminated glass sandwiched between substrates can be mentioned.

A transparent screen is a screen that allows the viewer to see through the scene on the other side of the screen and that displays image light projected onto the screen in a visible manner as an image. Specifically, it is a screen having a first surface and a second surface on the opposite side. The spectacle on the side of the second surface is transmitted so as to be visible to the observer on the side of the first surface, and the image light projected from the projector installed on the side of the first surface is transmitted to the observer on the side of the first surface. and a screen that is visually recognizable as an image to either one of the observers on the second surface side.
The transparent screen may be a reflective transparent screen that visibly displays image light projected from the first surface side as an image to an observer on the first surface side. It may be a transmissive transparent screen that visibly displays the projected image light as an image to an observer on the second surface side.
Embodiments of the functional laminated glass will be described below.

(reflective transparent screen)
A reflective transparent screen has a reflective image display film disposed between a first transparent substrate and a second transparent substrate.
The first transparent substrate and the reflective image display film are bonded together by a first adhesive layer, and the second transparent substrate and the reflective image display film are bonded together by a second adhesive layer. there is

Materials for the first transparent base material and the second transparent base material include the same materials as the transparent base material for the above-described functional laminated glass, and preferred embodiments are also the same.
As the first adhesive layer and the second adhesive layer, the same adhesive layers as those of the above-described functional laminated glass can be used, and the preferred forms are also the same.

In the reflective transparent screen, the image light projected from the projector and incident from the first surface of the reflective transparent screen is scattered by the reflective film of the reflective image display film to form an image, and the projector and It is visibly displayed as an image to a first observer on the same side.

After entering the reflective transparent screen from the first surface, the light of the scene on the first surface side is partly reflected by the reflective film and the rest is transmitted. Thereby, a second observer (not shown) on the side of the second surface can visually recognize the scene on the side of the first surface. Similarly, after entering the reflective transparent screen from the second surface, the light of the scene on the second surface side is partly reflected by the reflective film and the rest is transmitted. Thereby, the first observer on the first surface side can visually recognize the scene on the second surface side.

Note that the functional laminated glass may be one in which the first transparent substrate, the first adhesive layer, the functional film, the second adhesive layer, and the second transparent substrate are laminated in this order. It is not limited to the functional laminated glass of the embodiment.
For example, the reflective transparent screen may further have other layers. Other layers include, for example, a low-reflection layer that reduces reflection of light, a light attenuation layer that attenuates part of light, and an infrared shielding layer that shields infrared rays.
The functional laminated glass may be transmissive transparent screen, heat reflective laminated glass, decorative laminated glass, or mirror laminated glass.
The functional laminated glass may have a region where the functional film exists and a region where the functional film does not exist.

EXAMPLES The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.
Examples 1 to 3 and 7 are examples, and Examples 4 to 6 are comparative examples.

<Evaluation method>
(Viscosity of coating liquid)
The viscosity of the coating liquid was measured at 40° C. with an E-type viscometer. Specifically, the viscosity was obtained by inserting a cylindrical rotor into the sample and measuring the torque (shear stress) acting on the cylindrical surface when rotating at a constant speed. The rotation speed of the rotor was set to 100 [1/s].

(Maximum thickness of transparent resin layer)
The cross section of the film with the uneven structure in the thickness direction was observed with an electron microscope, and the thickness of the portion having the maximum height of the projections was observed to determine the maximum thickness of the transparent resin layer.

(bubble biting)
As a result of observing an arbitrary 260 μm square portion of the cross section of the film with a concave-convex structure with a laser microscope, when no bubbles exceeding 1 μm in diameter were observed, it was evaluated as ○, and when bubbles exceeding 1 μm in diameter were observed, it was evaluated as ×.

(Coatability)
When the coating liquid could be applied without any problem, it was evaluated as ◯, and when it could not be applied, it was evaluated as x.

(wet lamination property)
After the coating liquid was applied to the mold, a base material was laminated on the coating film and bonded together with a wet laminate nip. At this time, when the coating liquid did not seep out from the edge of the laminate, it was rated as ◯, and when the coating liquid did seep out, it was rated as x.

<Materials used>
(Photocurable resin)
A-DCP: Tricyclodecanedimethanol diacrylate (“A-DCP” manufactured by Shin-Nakamura Chemical Co., Ltd.).
U-6LPA: Urethane acrylate oligomer (“U-6LPA” manufactured by Shin-Nakamura Chemical Co., Ltd.).
FM-400: An esterification reaction product of neopentyl glycol, hydroxypivalic acid and acrylic acid (“KAYARD FM-400” manufactured by Nippon Kayaku Co., Ltd.).
UA-122P: Urethane acrylate oligomer (“UA-122P” manufactured by Shin-Nakamura Chemical Co., Ltd.).
DPCA-120: Dipentaerythritol polycaprolactone hexaacrylate (“KAYARAD DPCA-120” manufactured by Nippon Kayaku Co., Ltd.).
HX-620: caprolactone-modified hydroxypivalic acid neopentyl glycol diacrylate (“KAYARAD HX-620” manufactured by Nippon Kayaku Co., Ltd.).
UA-4200: Urethane acrylate oligomer (“UA-4200” manufactured by Shin-Nakamura Chemical Co., Ltd.).
Table 1 shows the acrylic equivalent, number of functional groups, molecular weight, viscosity and refractive index of these shining curable resins. The refractive index indicates the refractive index after photocuring.

(others)
Optimas: acrylic resin ("Optimas 7500" manufactured by Mitsubishi Gas Chemical Company).
Photopolymerization initiator: 1-hydroxycyclohexylphenyl ketone ("Omnirad 184" manufactured by IGM Resins B.V.).

<Example 1>
55 parts by mass of A-DCP, 21 parts by mass of U-6LPA and 25 parts by mass of UA-122P as photocurable resins, and 3 parts by mass of a photopolymerization initiator are mixed to form a transparent resin layer. I got the liquid.
A transparent PET film (biaxially stretched film, 150 mm square, 125 μm thick) was prepared as a substrate.
As a mold, a resin film having a stripe-patterned concave-convex structure as shown in FIG. 4 formed on the surface was prepared. The first direction was parallel to MD. Specifically, the stripe pattern shape is a structure in which a plurality of ridges having a fine uneven structure on the surface are arranged in one direction. It was 40 μm. The fine uneven structure on the surface of the ridges was obtained by applying a filler having an average particle size of 1.5 μm.

A coating liquid was applied to the surface of the mold by a die coating method, and a base material was placed thereon to form a curable resin layer.
Next, while the base material is pressed against the curable resin layer, the curable resin layer is irradiated with ultraviolet rays of 1000 mJ to cure the curable resin layer, and the transparent resin layer with the uneven structure of the mold transferred to the surface. formed. After that, the mold was peeled off from the surface of the transparent resin layer to obtain a film with an uneven structure.

<Example 2>
A coating liquid was prepared in the same manner as in Example 1, except that the composition of the coating liquid was changed as shown in Table 2, and a film with an uneven structure was produced.

<Example 3>
2.5 parts by weight of A-DCP, 4 parts by weight of FM-400, 8.5 parts by weight of DPCA-120 and 15 parts by weight of HX-620 as photocurable resins, 20 parts by weight of Optimas, and toluene , 40 parts by mass of ethyl acetate, and 3 parts by mass of a photopolymerization initiator were mixed to obtain a coating liquid for a transparent resin layer.
The same substrate and mold as used in Example 1 were prepared.

The coating liquid was applied to the surface of the mold by a die coating method, dried at 90° C. and 110° C. for 2 minutes, and then a substrate was placed thereon to form a curable resin layer.
Next, while the base material is pressed against the curable resin layer, the curable resin layer is irradiated with ultraviolet rays of 1000 mJ to cure the curable resin layer, and the transparent resin layer with the uneven structure of the mold transferred to the surface. formed. After that, the mold was peeled off from the surface of the transparent resin layer to obtain a film with an uneven structure.

<Example 4>
The same coating liquid, substrate and mold as used in Example 1 were prepared.
A coating liquid was applied to the surface of the substrate by a die coating method, and a mold was placed thereon to form a curable resin layer.
Next, while the mold is pressed against the curable resin layer, the curable resin layer is irradiated with ultraviolet rays of 1000 mJ to cure the curable resin layer, thereby forming a transparent resin layer with the concave-convex structure of the mold transferred to the surface. formed. After that, the mold was peeled off from the surface of the transparent resin layer to obtain a film with an uneven structure.

<Example 5>
A coating liquid was prepared in the same manner as in Example 4, except that the composition of the coating liquid was changed as shown in Table 2, and a film with an uneven structure was produced.

<Example 6>
A coating solution was prepared in the same manner as in Example 3, and the same substrate and mold as used in Example 3 were prepared.
The coating liquid was applied to the surface of the substrate by a die coating method, dried at 90° C. and 110° C. for 2 minutes, and then a mold was placed thereon to form a curable resin layer.
Next, while the mold is pressed against the curable resin layer, the curable resin layer is irradiated with ultraviolet rays of 1000 mJ to cure the curable resin layer, thereby forming a transparent resin layer with the concave-convex structure of the mold transferred to the surface. formed. After that, the mold was peeled off from the surface of the transparent resin layer to obtain a film with an uneven structure.

<Example 7>
A film with an uneven structure was produced in the same manner as in Example 3, except that the coating amount of the coating liquid was changed to make the maximum thickness of the transparent resin layer 350 μm.

The coating liquid used in each example, the formed curable resin layer, and the obtained film with uneven structure were evaluated as described above. Table 2 shows the results.

In Examples 1 to 3 and 7, no air bubbles exceeding 1 μm in diameter were observed in the evaluation of bubble entrapment, and a film with an uneven structure in which bubble entrapment was suppressed was obtained. On the other hand, in Examples 4 to 6, a large number of bubbles having a diameter of about 2 μm were observed in the evaluation of bubble entrapment, and a large number of bubble entrapment occurred.

REFERENCE SIGNS LIST 1 base material 2 curable resin layer 3 transparent resin layer M mold 10 reflective image display film 11 light scattering layer 13 first transparent resin layer 15 reflective film 19 second transparent resin layer , 31 protrusion, 33 first groove, 35 second groove, 37 region 39 groove.

Claims (7)

A method for producing a film with an uneven structure, which has a transparent resin layer having an uneven structure on its surface, and the transparent resin layer has a maximum thickness of 30 to 400 μm,
A coating liquid containing a curable resin and having a viscosity of 500 to 100,000 mPa·s at 25° C. is applied to the surface of the mold having an uneven structure corresponding to the uneven structure of the transparent resin layer, and Laminating a base material to form a curable resin layer,
curing the curable resin layer to form the transparent resin layer;
separating the transparent resin layer and the mold;
A method for producing a film with an uneven structure. The manufacturing method according to claim 1, wherein the uneven structure of the transparent resin layer includes a plurality of recesses, a plurality of protrusions, or a plurality of protrusions and recesses. 3. The manufacturing method according to claim 1, wherein the concave-convex structure of the transparent resin layer includes cylindrical, conical, truncated conical, hemispherical, prismatic, pyramidal or truncated pyramidal protrusions. The uneven structure of the transparent resin layer includes first grooves extending in a direction substantially parallel to the first direction of the transparent resin layer and second grooves extending in a direction substantially perpendicular to the first direction of the transparent resin layer. 3. The manufacturing method according to claim 1 or 2, wherein the two-dimensional pattern shape comprises 3. The manufacturing method according to claim 1, wherein the concave-convex structure of the transparent resin layer has a stripe pattern shape including grooves extending in a direction substantially perpendicular to the first direction of the transparent resin layer. A method for producing a functional film, comprising producing a film with an uneven structure by the production method according to any one of claims 1 to 5. 7. The method for producing a functional film according to claim 6, wherein a reflective film is formed on the uneven structure of the transparent resin layer of the film with uneven structure.

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