JP2019217735A - Multilayer structure having hydrophilic layer and antireflection layer provided on substrate - Google Patents

Abstract

To provide a multilayer structure having high transmissivity, and having jointly easy cleanability (antifouling property) and excoriation resistance.SOLUTION: A multilayer structure has a transparent substrate, a smooth hydrophilic layer provided as an outermost layer on one surface side of the transparent substrate, and an antireflection layer having a plurality of uneven structures provided as an outermost layer on the opposite surface side thereof, in which a roughness (average height difference of the uneven structure) and a pitch (mean distance between peaks of mutually adjacent convex parts) of the antireflection layer are in the range of 60 nm-800 nm.SELECTED DRAWING: None

Description

  The present invention relates to a multilayer structure in which a hydrophilic layer is provided on one surface side of a transparent substrate and an antireflection layer is provided on the opposite surface side.

  It is well known that a transparent material (for example, a lens) having a so-called moth-eye structure, which is one of nanometer-sized uneven structures, can reduce the reflectance (Non-Patent Document 1). Therefore, proposals have been made for a polarizing plate (Patent Document 2), a lighting fixture (Patent Document 3), a light guide plate (Patent Document 4), a prism sheet (Patent Document 5), etc., utilizing the excellent antireflection performance of the moth-eye structure. Has been done. On the other hand, the production of a transparent material having a nanometer-sized uneven structure such as a moth-eye structure is relatively complicated and has low productivity. The nanometer-sized convex structure (fine particles) is not completely ordered but relatively disordered. (Patent Document 6) has been proposed in which a film made of a transparent resin having a concave-convex structure (amorphous structure) similar to a moth-eye arranged in the following manner is easily produced. Further, proposals have been made of an antireflection film, an antireflection article, a polarizing plate, an image display device, a module, and a liquid crystal display device with a touch panel by the improved method of Patent Document 6 (Patent Document 7).

  However, the nanometer-sized uneven structure represented by such a moth-eye structure has a problem that dirt easily enters a concave portion and thus is difficult to be removed, and a portion to which dirt adheres loses antireflection properties. .

  As one means of solving this problem, the present inventors have developed a single-layer film having a nanometer-sized uneven structure made of a high-hardness and highly hydrophilic crosslinked resin having a component gradient structure in which hydrophilic groups are concentrated on the surface. It has already been proposed (Patent Document 1). This single-layer film can easily remove dirt by simple cleaning (wiping with water or the like), and is also useful as an antireflection film.

International Publication No. WO 2016/143778 JP-A-2003-302532 JP 2014-229497 A JP 2003-344855 A JP 2004-077632 A JP 2009-139796 A International Publication No. WO2018 / 034126

Nature 244, 281 (1973)

  According to the above prior art, the problem of the loss of the antireflection property due to dirt and the problem of the productivity relating to the formation of the moth-eye structure are being solved. However, the problem that the nanometer-sized uneven structure is weaker than a flat surface due to physical pressure (such as rubbing by applying pressure such as cleaning) has not been improved.

  On the other hand, in a display device such as a display, with the widespread use of a touch panel as typified by a smartphone, in order to maintain high visibility of a display object, a material for a display device and a member made of this material are required. There is an increasing demand for improving the luminous flux by increasing the transmittance, imparting easy-cleaning properties (anti-fouling properties), and improving durability (scratch resistance) for the cleaning work. However, there has not been proposed a transparent material which has a high transmittance which can sufficiently satisfy these requirements and has both easy cleaning properties (antifouling properties) and scratch resistance, and a member made of this material. In addition, demands for maintaining high visibility are also increasing in imaging devices such as CCD and CMOS image sensors.

  In view of such a problem, the present inventors have repeatedly studied and found that the transparent substrate, the smooth hydrophilic layer provided as the outermost layer on one surface side of the transparent substrate, and the outermost layer on the opposite surface side A multilayer structure having a specific anti-reflection layer having a plurality of concave-convex structures provided as a member (for example, a cover member) used in the above-described image display devices, sensors, and video devices typified by cameras and the like The present invention has been found to be useful as such, and has reached the present invention.

  That is, the multilayer structure of the present invention is a transparent substrate, a smooth hydrophilic layer provided as the outermost layer on one side of the transparent substrate, and a plurality of layers provided as the outermost layer on the opposite side. The roughness (average height difference of the uneven structure) and the pitch (average distance between the apexes of the adjacent convex portions) of the antireflective layer are in the range of 60 nm to 800 nm. It is characterized by being.

The water contact angle of the hydrophilic layer is preferably 30 ° or less.
Further, the surface concentration (Sa2) of at least one hydrophilic group of the hydrophilic functional group selected from the anionic hydrophilic group, the cationic hydrophilic group, and the hydroxyl group of the hydrophilic layer, and the hydrophilicity at a half point of the thickness of the hydrophilic layer. It is preferable that the gradient (Sa2 / Da2) with respect to the deep concentration (Da2) of the group is 1.1 or more.

The roughness and pitch of the uneven structure of the antireflection layer are preferably in the range of 100 nm to 600 nm.
Preferably, the uneven structure of the antireflection layer is a moth-eye structure.

The multilayer structure is preferably in the form of a sheet or a film.
A member for a video device according to the present invention is characterized by comprising the multilayer structure.
In the video device of the present invention, it is preferable that a member formed of a sheet or film-shaped multilayer structure is provided on the outermost side.

  As the video device, a display device, an imaging device, or a projection / projection device is preferable.

  ADVANTAGE OF THE INVENTION The multilayer structure of this invention has high transmittance | permeability, and has both easy cleaning property (antifouling property) and abrasion resistance. Therefore, this multilayer structure is useful as a member for video equipment.

In an Example, it is the schematic which shows the method of the sample preparation for measuring the gradient (Sa / Da) of anion concentration. 3 is a photograph of a moth-eye structure layer obtained in Example 1. 4 is a photograph of the planar hydrophilic layer obtained in Comparative Example 1. FIG. 4 is a diagram showing the results of total light transmittance measured in Example 1 and Comparative Example 1.

  The multilayer structure of the present invention includes a transparent substrate, a smooth hydrophilic layer provided as an outermost layer on one surface side of the transparent substrate, and a plurality of irregularities provided as an outermost layer on the opposite surface side. And an antireflection layer having a structure.

  Examples of the transparent substrate include substrates made of various transparent materials. The transparent material may be either an inorganic material or an organic material, but a material having high transparency is desirable. Examples of the transparent material include inorganic materials such as glass; polymethyl methacrylate (PMMA), triacetyl cellulose (TAC), polyethylene terephthalate (PET), polycarbonate (PC), cycloolefin polymer, polyvinyl chloride (PVC), Organic materials such as polystyrene, polyurethane, nylon, polyimide, acrylonitrile-butadiene-styrene (ABS) resin and epoxy resin; and the like.

  Among these transparent materials, glass, PMMA, TAC, and cycloolefin polymer are preferable from the viewpoints of higher transparency, optical uniformity (small birefringence), low refractive index, and low reflectance.

A smooth hydrophilic layer is provided as an outermost layer on one surface side of the transparent substrate. This hydrophilic layer preferably has an inclined structure in which hydrophilic groups are concentrated on the surface.
Among such inclined structures in which the hydrophilic groups forming the hydrophilic layer are concentrated on the surface, the surface concentration of at least one hydrophilic group of hydrophilic functional groups selected from anionic hydrophilic groups, cationic hydrophilic groups, and hydroxyl groups ( It is more preferable that the gradient (Sa2 / Da2) between Sa2) and the deep concentration (Da2) of the hydrophilic group at half the thickness of the hydrophilic layer is 1.1 or more.

  Materials that can form such a gradient structure in which hydrophilic groups are concentrated on the surface include, for example, the following materials (1) to (12).

(1) Specific monomer (I) having at least one kind of anionic hydrophilic group selected from sulfonic acid group, carboxyl group and phosphoric acid group, and having two or more (meth) acryloyl groups in one molecule Crosslinked resin obtained by polymerizing after removing the solvent from a composition containing compound (II) and a specific solvent having a large solubility parameter (WO 2007/064003)

(2) Polymer obtained from a monomer containing a compound having a bifunctional specific structure having a sulfonic acid group and / or a sulfonic acid group (Japanese Patent Application Laid-Open No. 2009-073923)

(3) Polyvalent monomer (II) having two or more (meth) acryloyl groups, and compound (IV) having at least one group selected from a mercapto group, a hydroxyl group, and an amino group and a sulfonic acid group (However, a mixture containing a mono (meth) acrylate having at least one anionic hydrophilic group selected from a sulfonic acid group, a carboxyl group, and a phosphoric acid group and the polyvalent monomer (II)) is polymerized. Cured product (WO 2012/014829)

(4) a sulfonic acid group having a specific monomer (I) having at least one kind of anionic hydrophilic group selected from a sulfonic acid group, a carboxyl group, and a phosphoric acid group and two or more (meth) acryloyl groups; , A polyvalent monomer (II) having no carboxyl group or phosphate group, and a monomer (I) / polyvalent monomer (II) molar ratio of 1/1000 or more and less than 1/30. Containing a solvent containing a monomer composition containing a compound having a solubility parameter σ of at least 9.3 (cal / cm ³ ) or more, and applying the mixture to a substrate. Crosslinked resin obtained by removing the solvent and polymerizing a monomer composition containing monomer (I) and monomer (II) (WO 2013/014733)

(5) Compound (I) having an anionic hydrophilic group and a functional group having a polymerizable carbon-carbon double bond, and three or more hydroxyl groups and a functional group having a polymerizable carbon-carbon double bond. Crosslinked resin obtained by polymerizing a composition containing compound (II) having three or more (WO 2015/178248)

(6) Compound (I) having at least one hydrophilic group selected from an anionic hydrophilic group, a cationic hydrophilic group, and a hydroxyl group and at least one functional group having a polymerizable carbon-carbon double bond (wherein When the group is a group having a hydroxyl group, there is one functional group having a polymerizable carbon-carbon double bond.) And a compound having two or more functional groups having a polymerizable carbon-carbon double bond (II (Provided that it may have a hydroxyl group, but has neither an anionic hydrophilic group nor a cationic hydrophilic group), and an anionic hydrophilic group, a cationic hydrophilic group, or two or more hydroxyl groups. At least one selected from a surfactant (III) having a hydrophilic part having a hydrophilic part and a hydrophobic part comprising an organic residue, and a compound (IV) having a siloxane bond and a molecular weight of 200 to 1,000,000. Crosslinked resin obtained by polymerizing a composition containing two compounds (provided that the surfactant (III) and the compound (IV) do not have a polymerizable carbon-carbon double bond) (WO 2015/2015). 087810)

(7) A modified acrylic resin film obtained from an acrylic resin having an anionic hydrophilic group, wherein the concentration of the anionic hydrophilic group on the surface is such that the concentration of the anionic hydrophilic group on the surface of the acrylic resin-based film is １ ／. The surface of the acrylic resin film having a concentration higher than the concentration of the hydrophilic group, a group containing at least one anionic hydrophilic group and a polymerizable carbon-carbon double bond in one molecule, an amino group, a mercapto group, and a hydroxyl group. Modified acrylic resin obtained by treating with a specific compound (A) having at least one group selected from the group consisting of (WO 2013/187311)

(8) selected from the group consisting of at least one anionic hydrophilic group forming an ion pair with an onium ion of an aminosilicone, a group containing a polymerizable carbon-carbon double bond, an amino group, a mercapto group, and a hydroxyl group. Acrylic resin cured product obtained by treating the surface of a cured product (X) made of an acrylic resin with a compound (A) having one or more groups in one molecule (WO 2016/136811)

(9) a polymer (i) having a —SO ₃ M group and an epoxy group, wherein M represents a hydrogen atom, an alkali metal, an alkaline earth metal, or an ammonium ion; a hydroxyl group bonded to a silane atom; Cured product of a composition containing a silane compound (ii) having a total of two or more groups or atoms selected from the group consisting of an alkoxy group bonded to a silane atom and a halogen atom bonded to a silane atom (WO 2013/054877) issue)

(10) -SO ₃ M group (M: a hydrogen atom, an alkali metal ion, 1 / bivalent alkaline earth metal ions, ammonium ions or an amine ion,), an epoxy group, certain構性unit containing an alkoxysilyl group Cured product of the composition containing the copolymer (i) containing the structural units represented by (1), (2) and (3) (WO 2014/168122)

(11) A specific copolymer (i) having a sulfonic acid-containing group, an epoxy group, and a specific alkoxysilyl group in a molecule, or a cured product of a composition containing the copolymer (i) (International publication) No. 2014/168123)

(12) A composition comprising a specific copolymer (i) having a sulfonic acid-containing group, an epoxy group, and a specific alkoxysilyl group in a molecule and an amino resin (ii) is cured (see International Publication No. 2016/017719)
The method for applying the composition or polymer to the transparent substrate before curing (crosslinking) the material for the hydrophilic layer can be performed by various coating methods. Examples of the coating method include a gravure coating method, a bar coating method, a flow coating method, a spin coating method, a spray coating method, and other known methods. Above all, a gravure coating method, a bar coating method, a spin coating method and the like are preferable.
Curing (crosslinking) of the composition or polymer is performed by adding a polymerization initiator or a catalyst as necessary and heating or irradiating radiation such as ultraviolet (UV). Detailed curing (crosslinking) conditions and the like are described in detail in the documents exemplified in the above (1) to (12). The hydrophilic layer formed from these materials has excellent scratch resistance.

  The water contact angle of the hydrophilic layer is preferably 30 ° or less, more preferably 20 ° or less, and further preferably 10 ° or less. When the water contact angle is in the above range, the hydrophilic layer tends to be more excellent in antifouling property, antifogging property and the like. The water contact angle is usually 0 ° or more.

  An antireflection layer having a plurality of uneven structures is provided as an outermost layer on the surface (opposite surface) of the transparent substrate opposite to the surface on which the smooth hydrophilic layer is provided. The roughness (Ra) and pitch (A) of the antireflection layer are in the range of 60 nm to 800 nm. Here, the roughness refers to an average height difference of the concavo-convex structure, and the pitch refers to an average distance between vertices of adjacent convex portions of the concavo-convex structure. The roughness is a value obtained as an arithmetic average roughness. When the roughness and the pitch are less than 60 nm, the reflectance of visible light increases and the transmittance decreases. If the roughness and the pitch exceed 800 nm, the antireflection effect cannot be obtained. From the viewpoint of further improving the transmittance while obtaining the antireflection effect, the roughness and pitch of the antireflection layer are more preferably in the range of 100 nm to 600 nm.

  The ratio Ra / A between roughness and pitch in the antireflection layer is preferably in the range of 0.4 to 3, more preferably in the range of 0.5 to 2. If it is less than 0.4, the reflectance tends to decrease, and if it exceeds 3, the structure of the projections is broken by pressure such as contact, and the antireflection property tends to be easily reduced.

  From the viewpoint of improving the transmittance while improving the antireflection property, as the uneven structure in the antireflection layer, for example, a moth-eye structure described in Non-Patent Document 1 and a convex structure (fine particles) described in Patent Documents 6 and 7 And (2) are preferably non-ordered and relatively disorderly arranged in a nanometer size and are relatively disordered, similar to a moth-eye structure (amorphous structure), and an uneven structure proposed in Patent Document 1.

  The method of forming the uneven structure layer of the antireflection layer may be appropriately selected depending on the purpose and the like.For example, a replica mold having a structure corresponding to a previously formed uneven structure is applied to a transparent substrate. Imprinting method in which a mold composed of silica fine particles and a curable resin is applied and cured after being bonded to the surface of a layer made of the curable composition and cured together with the replica mold, and then etched using high frequency plasma or the like. After the method (the method described in Patent Document 6), the metal oxide fine particles are made to protrude from the interface containing the metal oxide fine particles and the curable compound from the interface opposite to the interface on the substrate side. A method of curing the compound (the method described in Patent Document 7) and the like can be mentioned.

  Examples of the material capable of forming the concavo-convex structure by the above various methods include a radiation curable material such as a thermoplastic material, a thermosetting material, and a UV curable material. Among these, a thermosetting material and a UV-curable material are preferable, and a UV-curable material that completes curing in a short time and increases productivity is more preferable.

  Examples of the compound contained in the UV curable material include, for example, a methacrylate compound or an acrylate compound (hereinafter, referred to as (meth) acrylate having at least one group selected from the group consisting of an acryloyl group and a methacryloyl group (hereinafter, also referred to as a (meth) acrylate group). (Meth) acrylate compounds), epoxy compounds having one or more epoxy groups, and vinyl compounds having one or more vinyl groups (excluding acryloyl and methacryloyl groups) in one molecule. The (meth) acrylate compound includes at least one compound selected from the group consisting of a urethane acrylate compound having at least one (meth) acrylate group and at least one urethane bond, acrylic acid and methacrylic acid, and an epoxy compound. Epoxy (meth) acrylate compounds obtained by reacting with a compound having one or more groups are included.

As the compound contained in the UV curable material, among these, a (meth) acrylate compound having two or more (meth) acrylate groups is preferable because of high curability.
As a material for forming the antireflection layer, a hydrophilic material that is easily hydrophilized and easily obtains an antifouling property (easy cleaning property) of a concavo-convex structure is preferable. Therefore, the antireflection layer preferably has a tilted structure in which hydrophilic groups are concentrated on the surface.

As a suitable material capable of forming the uneven structure while forming the inclined structure in which such hydrophilic groups are concentrated on the surface, among the materials exemplified as the material capable of forming the hydrophilic layer described above, a UV-curable material is used. The materials (1) to (8) are mentioned.
Curing (crosslinking) of the composition is performed by adding a polymerization initiator or the like as necessary and irradiating with radiation such as UV. Detailed curing (crosslinking) conditions and the like are described in detail in the documents exemplified in the above (1) to (8).

  In the multilayer structure of the present invention, at least two layers of a smooth hydrophilic layer on the outermost layer on one surface side of the transparent substrate and an antireflection layer having a plurality of uneven structures on the outermost layer on the opposite surface side have a transparent substrate. It is a laminated body laminated on a material. Therefore, another layer may be laminated between the transparent substrate and the hydrophilic layer, between the antireflection layer and the transparent substrate, or between both. Examples of other layers include an adhesive layer or an adhesive layer for bonding a transparent substrate and a hydrophilic layer (antireflection layer), and optical functional layers such as a polarizing film layer and a light guide plate layer.

  When only antifouling property (easy cleaning property) and high visibility (transmittance) are simply required, the multilayer structure of the present invention is provided with a smooth hydrophilic layer on one surface of a transparent substrate, A multilayer structure having a three-layer structure (hydrophilic layer / transparent substrate / anti-reflection layer) in which an antireflection layer having a plurality of uneven structures is provided, or an adhesive layer for adhering each layer of the three-layer structure. A multilayer structure having a five-layer structure (hydrophilic layer / adhesive layer / transparent substrate / adhesive layer / anti-reflection layer) is preferred.

  Each layer constituting the multilayer structure may contain an additive as long as the effects of the present invention are not impaired. Examples of the additive include an antioxidant, HALS, a specific wavelength absorber that absorbs and cuts a specific wavelength represented by a UV absorber, a filler (filler), a dye, a pigment, a fragrance, and the like.

The shape of the multilayer structure of the present invention is not particularly limited, but is typically a sheet or film shape. Further, the multilayer structure of the present invention may be used after further processing such as cutting in accordance with various purposes.
The multilayer structure of the present invention has a high transmittance and is excellent in antifouling property (easy cleaning property), so that it is suitable as a member for video equipment. Because of these excellent characteristics, it is particularly preferable that the member for a video device comprising the multilayer structure of the present invention is provided as the outermost part of the video device. When the multilayer structure of the present invention is used as a member for a video device, the surface of the smooth hydrophilic layer may face outward of the video device (the antireflection layer having a plurality of uneven structures faces the inside). preferable. By doing so, the performance that can be imparted to the antireflection layer can be exhibited while exhibiting the performance of the smooth hydrophilic layer.

  Video equipment that can be provided with the above members, for example, display equipment typified by a liquid crystal display, an organic EL display, electronic paper, etc .; CCD image sensors, CMOS image sensors, high-definition cameras, surveillance cameras, video cameras, WEB cameras, network cameras Imaging devices such as stereo cameras for surveying and avoiding danger of vehicles; head mounted displays, projection mapping, slide projectors, overhead projectors, CRT projectors, liquid crystal projectors, DLP (Digital Light Processing) projectors, Projection and projection equipment typified by an LCOS (Liquid Crystal On Silicon) projector, a CLV (Grating Light Valve) projector, and the like.

Hereinafter, the present invention will be described in more detail with reference to Examples and the like, but the present invention is not limited to only these Examples.
In the present invention, physical properties of the coating were evaluated as follows.

<Measurement of hydrophilic group concentration ratio>
As in the sample preparation shown in FIG. 1, the sample is cut obliquely and subjected to a hydrophilic group (sulfonic acid group, carboxyl group, phosphate group, quaternary ammonium) using a time-of-flight secondary ion mass spectrometer (TOF-SIMS). Group or hydroxyl group), the fragment ion concentration (Sa) of the outer surface derived from the hydrophilic compound and the fragment ion concentration (Da) between the intermediate point and the fragment ion concentration are measured. The ratio of the concentration of the hydrophilic group derived from the hydrophilic compound at the intermediate point between the outer surface of the film in contact with the outside air and the inner surface and the outer surface of the film, that is, the gradient of the hydrophilic group concentration (Sa / Da) was determined.

(Analyzer and measurement conditions)
TOF-SIMS; TOF-SIMS5 manufactured by ION TOF
Primary ion; Bi ₃ ²⁺ (acceleration voltage 25 kV)
Measurement area: 400 μm ²
Use a neutralization gun for charging correction for measurement

(Sample preparation, etc.)
As shown in FIG. 1, a sample in which the layer 20 is provided on the surface of the base material 10 is subjected to precision oblique cutting in the cutting direction 30 and then cut out to a size of about 10 × 10 mm ² , A mesh is applied and fixed to the sample holder, and a time-of-flight secondary ion mass spectrometer (TOF-SIMS) is applied to the layer surface 40 in contact with the outside air and the inside 50 of the layer (at a point of 1/2 the layer thickness). And the hydrophilic group concentration was measured.

(Evaluation)
The evaluation was performed using the following formula. The relative intensity (relative to the total detected ions) was used as the ion concentration at each measurement point.
Sa / Da (hydrophilic group concentration ratio, gradient) = hydrophilic group concentration on layer surface 40 / hydrophilic group concentration at point where thickness of layer 20 is 1/2

<Measurement of water contact angle>
Using a water contact angle measuring device CA-V type manufactured by Kyowa Interface Science Co., Ltd., three samples were measured for one sample, and the average value of these values was taken as the value of the water contact angle.

<Evaluation of antifouling property>
A mixture of oleic acid (100 g), castor oil (150 g), and Mitsui Blue RR (0.4 g) (hereinafter abbreviated as "contaminant") was prepared as a soil mimic substance. About 2 ml of this contaminant was dropped on the surface of the test specimen, and the contaminant was spread on the surface of the test specimen. After that, 50 times of spraying with distilled water were performed, and the contaminated state was visually determined.
When there is almost no adhesion of contaminants on the test sheet surface: ○
If it remains slightly adhered: △
When clearly adhered and remained: ×

<Evaluation of scratch resistance>
The steel wool # 0000 was reciprocated 10 times with a load of 1 kg, and the state of the scratch was visually confirmed.
When no scratches are found: 範 囲 A range of 1 to 5 scratches: △
When the number of scratches is more than 5 and countless: ×

<Electron microscope observation>
The measurement was performed using a scanning electron microscope (SEM) S-4800 manufactured by Hitachi High-Technologies Corporation and a Phenom ProX desktop scanning electron microscope manufactured by Phenom-world.

<Transmittance at 546 nm and Total Light Transmittance>
The measurement was performed using a spectrophotometer U4100 spectrophotometer manufactured by Hitachi, Ltd.

[Preparation Example 1]
(Preparation of polymerizable composition)
According to Table 1 below, a polymerizable composition having a solid content of 80% by weight was prepared.

[Example 1]
(Preparation of coating composition)
To 10.0 g of the polymerizable composition obtained in Preparation Example 1, 0.24 g of Darocur 1173 (BASF) as a UV polymerization initiator and 10.0 g of PGM (1-methoxy-2-propanol) as a diluent were added and mixed. A coating composition having a solid content of 40% by weight was prepared.

(Lamination of smooth hydrophilic layer on substrate surface)
A coating composition is applied to a polymethyl methacrylate plate having a thickness of 2 mm (trade name: Acrylite L001, manufactured by Mitsubishi Chemical Corporation, thickness: 2 mm, hereinafter abbreviated as PMMA plate) using a bar coater # 5, and a 40 ° C. hot air dryer. For 3 minutes.

Then, UV irradiation (measurement with UVCURE PLUS-II, Heraeus UVCURE, UVA metal halide lamp, manufactured by UB012-5BM Eye Graphic Co., Ltd., illuminance UVA 340 mW / cm ² , integrated light amount UVA 3400 mJ / cm ² , Heraeus Co., Ltd.) A PMMA plate having a smooth hydrophilic layer having a thickness of 3 μm on one side of was obtained. Table 2 shows the inclination in the thickness direction of the laminated smooth hydrophilic layer.

(Lamination of moth-eye structure film layer on opposite surface)
The same coating composition as described above is applied to the opposite surface (uncoated surface) of the PMMA plate having a hydrophilic film laminated on the surface obtained above with a bar coater # 15, and a moth-eye structure is provided under reduced pressure of <1 mmHg. After bonding the resin mold, UV irradiation was performed under atmospheric pressure in the same manner as described above, and an anti-reflection film having a 8 μm-thick moth-eye structure was laminated on the back surface of the PMMA plate.

  In this way, a PMMA plate having a smooth hydrophilic layer on the surface and a moth-eye structure film layer on the opposite surface was obtained. Table 3 shows the evaluation results. FIG. 2 shows a microscopic observation diagram of the formed antireflection film having the moth-eye structure.

[Example 2]
(Production of a film having a hydrophilic layer)
A PET film in which a smooth hydrophilic layer was laminated on a 100 μm-thick easily-adhesive PET film (trade name: Lumilar 100-U34, manufactured by Toray Co., Ltd.) was produced in the same manner as in Example 1.

(Production of a film having a moth-eye structure layer)
A PET film in which an anti-reflection film having a moth-eye structure was laminated on a 100 μm-thick easily-adhesive PET film in the same manner as in Example 1 was produced.

(Preparation of adhesive)
10 g of Takelac A312 (solid content: 50 wt%, manufactured by Mitsui Chemicals), 1 g of Takenate D160N (solid content: 75 wt%, manufactured by Mitsui Chemicals), 0.12 g of dioctyltin dilaurate (2000 ppm / solid content), and 26 g of ethyl acetate were mixed. A clear adhesive of 16% by weight was obtained.

(Lamination of film on PMMA plate)
The same adhesive as described in Example 1 was applied to one side of a PMMA plate using a bar coater # 5 and dried with a hot air drier at 40 ° C. for 2 minutes to obtain a PET film having the hydrophilic layer under a reduced pressure of <1 mmHg. The laminate was returned to atmospheric pressure and a PMMA plate having a hydrophilic PET film attached on one side was obtained (film thickness of adhesive layer: 1 μm).

  Similarly, a PET film having a moth-eye structure layer is stuck on a surface of a PMMA plate on which a hydrophilic PET film is stuck on one side, on which the film is not stuck, and cured in an oven at 80 ° C. for 24 hours. A laminate having the following composition: agent / PMMA plate / adhesive / PET film having moth-eye structure layer was obtained. Table 3 shows the evaluation results.

[Comparative Example 1]
In the same manner as in Example 1, a PMMA plate having a smooth hydrophilic layer laminated on both surfaces was produced.

[Comparative Example 2]
The base material PMMA plate used in Example 1 was evaluated as it was.

Claims (10)

  A transparent substrate, a smooth hydrophilic layer provided as an outermost layer on one surface side of the transparent substrate, and an antireflection layer having a plurality of uneven structures provided as an outermost layer on the opposite surface side. A multilayer structure having a roughness (average height difference of the concavo-convex structure) and a pitch (average distance between apexes of adjacent protrusions) of the antireflection layer in a range of 60 nm to 800 nm.   The multilayer structure according to claim 1, wherein a water contact angle of the hydrophilic layer is 30 ° or less.   The surface concentration (Sa2) of at least one hydrophilic group of a hydrophilic functional group selected from an anionic hydrophilic group, a cationic hydrophilic group, and a hydroxyl group of the hydrophilic layer and the concentration of the hydrophilic group at half the thickness of the hydrophilic layer The multilayer structure according to claim 1, wherein a gradient (Sa2 / Da2) with respect to a deep concentration (Da2) is 1.1 or more.   The multilayer structure according to claim 1, wherein a roughness and a pitch of the uneven structure of the antireflection layer are in a range of 100 nm to 600 nm.   The multilayer structure according to any one of claims 1 to 4, wherein the uneven structure of the antireflection layer is a moth-eye structure.   The multilayer structure according to any one of claims 1 to 5, which is in the form of a sheet or a film. An imaging device member comprising the multilayer structure according to claim 1.   The member for a video device comprising the multilayer structure according to claim 7, wherein the video device is a display device, an imaging device, or a projection projection device.   An imaging device comprising the sheet or film-shaped multilayer structure according to claim 6 on the outermost side.   10. The video device according to claim 9, wherein the video device is a display device, an imaging device, or a projection projection device.