Void layer, laminate, method for manufacturing a void layer, optical component, and optical device

Abstract

The purpose of the present invention is to provide an air gap layer in which a bonding agent or an adhesive does not readily penetrate into an air gap.　In order to achieve the above-described purpose, an air gap layer according to the present invention is formed by chemically bonding particles with each other, and is characterized in that: the void fraction of the air gap layer is 35% by volume or more; the particles are inorganic-organic composite particles, each of which is obtained by bonding an organic group to an inorganic compound; the organic group comprises an R1 group that is a linear or branched alkyl group, and an R2 group that contains a carbon-carbon unsaturated bond; and the molar proportion of the R2 group relative to the total of the R1 group and the R2 group is 1-30% by mole.

Description

[Technical Field]

[0001] The present invention relates to a void layer, a laminate, a method for manufacturing a void layer, an optical component, and an optical device. [Background technology]

[0002] In optical devices, for example, an air layer with a low refractive index is used as a total internal reflection layer. Specifically, for example, in a liquid crystal device, each optical film component (e.g., a light guide plate and a reflector plate) is laminated with an air layer in between. However, when components are separated by an air layer, problems such as component deflection may occur, especially when the components are large. Furthermore, with the trend towards thinner devices, integration of each component is desired. For this reason, each component is integrated with adhesive without an air layer (for example, Patent Document 1). However, if the air layer that plays the role of total internal reflection is eliminated, optical properties such as light leakage may deteriorate.

[0003] Therefore, it has been proposed to use a low refractive index layer instead of an air layer. For example, Patent Document 2 describes a structure in which a layer with a lower refractive index than the light guide plate is inserted between the light guide plate and the reflector plate. As the low refractive index layer, for example, a void layer with air gaps is used in order to make the refractive index as close to that of air as possible.

[0004] Furthermore, an integrated configuration with an adhesive layer has been proposed to introduce the void layer into the device (Patent Document 3). [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2012-156082 [Patent Document 2] Japanese Patent Application Publication No. 10-62626 [Patent Document 3] Japanese Patent Publication No. 2014-46518 [Overview of the project] [Problems that the invention aims to solve]

[0006] The void layer is used, for example, by laminating it with other layers via an adhesive layer. However, when the void layer and the adhesive layer are laminated, the adhesive or glue constituting the adhesive layer may penetrate into the voids of the void layer, filling the voids and potentially reducing the porosity of the void layer and increasing its refractive index. The higher the porosity of the void layer, the easier it is for the adhesive or glue to penetrate. Furthermore, in high-temperature environments, the molecular motion (reduction in elastic modulus) of the adhesive or glue makes it easier for the adhesive or glue to penetrate the voids. In high-humidity environments, the water absorption of the adhesive or glue makes it easier for the adhesive or glue to penetrate the voids.

[0007] To suppress or prevent the penetration of the adhesive into the void, it is preferable to use an adhesive with a high modulus of elasticity (hardness) as much as possible. However, if the adhesive has a high modulus of elasticity (hardness), there is a risk that the adhesive strength or bonding strength will decrease. Conversely, if the adhesive has a low modulus of elasticity (softness), it is easier to obtain high adhesive strength or bonding strength, but there is a risk that the adhesive will penetrate into the void more easily.

[0008] To suppress or prevent the penetration of the adhesive or bonding agent into the voids, for example, it is conceivable to form a layer capable of suppressing the penetration of the adhesive or bonding agent (penetration-inhibiting layer) on the void layer using a substance other than the adhesive or bonding agent. However, in that case, a separate step for forming the penetration-inhibiting layer is required in addition to the step for forming the void layer, which leads to an increase in the manufacturing process.

[0009] For these reasons, a void layer is needed that prevents adhesives or glues from easily penetrating the voids.

[0010] Therefore, the present invention aims to provide a void layer, a laminate, a method for manufacturing a void layer, an optical member, and an optical device in which adhesives or glues do not easily penetrate the voids. [Means for solving the problem]

[0011] To achieve the above objective, the void layer of the present invention is A void layer formed by chemically bonding particles together, The porosity of the aforementioned void layer is 35 volume% or more. The aforementioned particles are inorganic-organic composite particles in which an organic group is bonded to an inorganic compound. The aforementioned organic group is a linear or branched alkyl group R 1 The group and the group R which contains a carbon-carbon unsaturated bond. 2 Includes the base, R 1 Base and R 2 R for the sum of the bases 2 The base is characterized by having a molar ratio of 1 to 30 mol%.

[0012] The laminate of the present invention is characterized by comprising the void layer of the present invention and an adhesive layer directly laminated on one or both sides of the void layer.

[0013] The present invention provides a method for producing a void layer, characterized by comprising a coating step of coating a dispersion containing the particles and a drying step of drying the coated dispersion.

[0014] The optical component of the present invention is an optical component that includes the laminate of the present invention.

[0015] The optical device of the present invention is an optical device that includes the optical component of the present invention. [Effects of the Invention]

[0016] According to the present invention, it is possible to provide a void layer, a laminate, a method for manufacturing a void layer, an optical member, and an optical device in which adhesives or glues do not easily penetrate the voids. [Brief explanation of the drawing]

[0017] [Figure 1] FIG. 1 is a process cross-sectional view schematically showing an example of a method for forming a laminate of the present invention in which a void layer 21, an intermediate layer 22, and an adhesive layer 30 are laminated on a resin film 10 in the present invention. [Figure 2] FIG. 2 is a diagram schematically showing a part of a process in a method for manufacturing a laminated film (laminated film roll) in a roll shape and an example of an apparatus used therefor. [Figure 3] FIG. 3 is a diagram schematically showing a part of a process in a method for manufacturing a laminated film roll and another example of an apparatus used therefor.

MODE FOR CARRYING OUT THE INVENTION

[0018] Next, the present invention will be described more specifically with examples. However, the present invention is not limited in any way by the following description.

[0019] The void layer of the present invention, for example, the R 1 group may be a linear or branched alkyl group having 1 to 6 carbon atoms.

[0020] In the R 2 group in the void layer of the present invention, the carbon-carbon unsaturated bond may be, for example, one or more in one R 2 group. The carbon-carbon unsaturated bond may be, for example, a carbon-carbon double bond or a carbon-carbon triple bond. When there are a plurality of carbon-carbon unsaturated bonds, the carbon-carbon unsaturated bonds may be, for example, either a carbon-carbon double bond or a carbon-carbon triple bond, or both.

[0021] The void layer of the present invention, for example, the R 2 group may be a group represented by the following chemical formula (R 2 ).

Chemical formula

[0022] The void layer of the present invention is, for example, The aforementioned chemical formula (R 2 ) in R 21 , R 22 and R 23 Each of these is either a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and they may be the same or different from each other. R 24This may be a void layer consisting of a linear or branched alkylene group having 1 to 6 carbon atoms, an oxycarbonyl group, an ether group, or a linear or branched alkylene oxycarbonyl group having 1 to 7 carbon atoms, or it may not exist.

[0023] The void layer of the present invention is, for example, the R 2 The groups are CH2=CH- and CH2=CH-(CH2). 1-6 -, CH2=C(CH3)-COO-, CH2=CH-O-, CH2=C(CH3)-COO-(CH2) 1-6 - or CH2=C(CH3)-CH2- may also be used. However, "-(CH2) 1-6 The symbol "-" represents a linear alkylene group with 1 to 6 methylene groups, meaning it is a methylene group, ethylene group (dimethylene group), trimethylene group, tetramethylene group, pentamethylene group, or hexamethylene group.

[0024] The void layer of the present invention may, for example, contain at least one skeletal atom selected from the group consisting of Si, Mg, Al, Ti, Zn, and Zr in the inorganic compound in the particles.

[0025] The void layer of the present invention may be, for example, a silicone porous material. Here, "silicone porous material" refers to a polymer porous material containing siloxane bonds, and includes, for example, a porous material containing silsesquioxane as a constituent unit.

[0026] The void layer of the present invention may, for example, have a refractive index of 1.25 or less.

[0027] The laminate of the present invention may, for example, have an intermediate layer between the void layer and the adhesive layer, and the intermediate layer may be a layer formed by the union of the void layer and the adhesive layer.

[0028] In the laminate of the present invention, for example, the adhesive layer is formed from an adhesive coating liquid containing a (meth)acrylic polymer, and the (meth)acrylic polymer may be a (meth)acrylic polymer with a weight-average molecular weight of 1.5 million to 2.8 million obtained by polymerizing 3 to 10% by weight of a heterocyclic acrylic monomer, 0.5 to 5% by weight of (meth)acrylic acid, 0.05 to 2% by weight of a hydroxyalkyl (meth)acrylate, and 83 to 96.45% by weight of an alkyl (meth)acrylate as monomer components.

[0029] In the laminate of the present invention, for example, the (meth)acrylic polymer may include a (meth)acrylic polymer that has been crosslinked with a crosslinking agent.

[0030] In the laminate of the present invention, for example, The aforementioned adhesive layer is A step to prepare an adhesive coating solution comprising a (meth)acrylic polymer, a monomer having one or two reactive double bonds in one molecule, an isocyanate crosslinking agent, and an organic peroxide, The adhesive coating step involves applying the adhesive coating liquid to the substrate, A heating and drying step in which the substrate to which the adhesive coating liquid has been applied is heated and dried, The layer may be formed by a method including the following:

[0031] In the laminate of the present invention, for example, the monomer having one or two reactive double bonds may be a heterocyclic acrylate.

[0032] The laminate of the present invention, for example, has a storage modulus of 1.0 × 10⁻¹⁰ at 23°C for the adhesive layer. 5 That's fine too.

[0033] The laminate of the present invention may have a refractive index of 1.25 or less after, for example, a heat and humidification durability test in which it is held at a temperature of 60°C and a relative humidity of 90% for 1000 hours.

[0034] As described above, by using the void layer of the present invention, the laminate of the present invention can suppress significant penetration of the adhesive layer into the void layer, for example, especially under long-term heating and humidification durability tests.

[0035] The reason (mechanism) why the laminate of the present invention can achieve both adhesive strength and resistance to the penetration of adhesives into voids can be considered, for example, as follows.

[0036] First, the particles in the void layer are R groups containing carbon-carbon unsaturated bonds. 2 If it contains a group (for example, a vinyl group), R 2 The bases experience steric hindrance and electrostatic repulsion. 2 Due to steric hindrance and electrostatic repulsion between the groups, when the particles incorporate the synthetic solvent in the void layer and gel (form a skeleton), they form a gel structure with wider intermolecular distances. As a result, the diameter of the voids in the void layer increases after the synthetic solvent is removed from the skeleton of the void layer. Furthermore, the electrostatic repulsion also acts when the particles accumulate to form the void layer, increasing the amount of air contained in the void layer, and consequently lowering the initial refractive index. In addition, the increase in the refractive index of the void layer due to moisture absorption of the adhesive layer under heating and humidification conditions, and the penetration of the adhesive layer into the voids due to the apparent decrease in elastic modulus at high temperatures, occurs because the sol component from the adhesive layer penetrates into the voids of the void layer. However, the amount of penetrating component contained in the adhesive layer is constant if the thickness of the adhesive layer is fixed. Therefore, if the porosity of the void layer itself increases, the proportion of the original voids filled with adhesive to the entire void layer after the heating and humidification durability test will inevitably decrease. As a result, the increase in refractive index after the heating and humidification durability test is suppressed. However, these descriptions are illustrative and do not limit the present invention in any way.

[0037] In order to easily obtain the effect of the present invention, which is that adhesives or glues do not easily penetrate into the voids of the void layer, the R 2 The content of the group is preferably neither too high nor too low. 2The reason why it is preferable not to have too high a content of the group can be considered, for example, as follows: First, the group R, which contains a carbon-carbon unsaturated bond. 2 When a group is present, the steric hindrance and electrostatic repulsion tend to increase the diameter of the voids in the void layer. Therefore, the R 2 In order to prevent the void diameter from becoming too large due to excessive steric hindrance or electrostatic repulsion between the groups causing the intermolecular distance to widen too much, the aforementioned R 2 It is preferable that the content of the base is not too high. For the same reason, in order to prevent the void diameter per void from becoming too large, the R 2 It is preferable that the content of the group not be too high. If the void system of the void layer is too large, the range of target Mw (weight-average molecular weight) having a molecular size suitable for the void diameter in the adhesive layer expands, and as a result the amount of sol component that can penetrate the voids increases. As a result, the voids in the void layer may become more easily filled and the refractive index may increase, so in order to prevent this, the R 2 It is preferable that the content of the group is not too high. However, these descriptions are illustrative and do not limit the present invention in any way.

[0038] Furthermore, the void layer of the present invention may also include, for example, nanoparticles surface-modified with a compound having surface orientation properties.

[0039] In the void layer of the present invention, for example, the compound having surface orientation is an alkoxysilane derivative, and the alkoxysilane derivative may contain a fluoroalkyl group having 5 to 17 or 5 to 10 fluorine atoms. The fluoroalkyl group may be an alkyl group in which only some of the hydrogen atoms are substituted with fluorine, or it may be an alkyl group in which all of the hydrogen atoms are substituted with fluorine (perfluoroalkyl group).

[0040] The void layer of the present invention may, for example, contain the nanoparticles in an amount of 10 to 50% by mass relative to the skeletal components of the void layer.

[0041] The method for manufacturing the void layer of the present invention may, for example, involve forming the void layer and simultaneously forming a layer made of nanoparticles inside the void layer.

[0042] If the void layer of the present invention contains nanoparticles surface-modified with a compound having surface orientation properties, for example, the adhesive layer will be less likely to penetrate the void layer. The reason (mechanism) for this can be considered as follows. First, the surface orientation property (transferability to the air interface) of a compound having surface orientation properties (for example, a compound having perfluoroalkyl) is used to impart surface orientation properties to the nanoparticles surface-modified with the compound. However, while a compound having surface orientation properties alone can modify the surface of the void layer, it is insufficient to suppress the penetration of macroscopic adhesives. Therefore, the nanoparticles fill the voids on the outermost surface of the void layer, physically suppressing the penetration of adhesives. However, nanoparticles that are not surface-modified do not have surface orientation properties, so they simply exist in the void layer without oriented to the surface of the void layer, and do not produce a penetration suppression effect. By modifying the nanoparticles with a compound having surface orientation properties, the nanoparticles acquire surface orientation properties toward the void layer. As a result, as described above, the nanoparticles fill the voids on the outermost surface of the void layer, physically suppressing the penetration of adhesives. In other words, nanoparticles modified with a surface-oriented compound fill the voids on the outermost surface of the void layer, thereby forming a penetration-inhibiting layer for adhesives or bonding agents on the outermost surface (surface layer). As a result, as mentioned above, the step of forming another penetration-inhibiting layer is unnecessary, and the increase in manufacturing steps due to the formation of the penetration-inhibiting layer can be avoided. However, these mechanisms are merely illustrative and do not limit the present invention in any way. To produce the void layer of the present invention, for example, nanoparticles modified with a surface-oriented compound can be added to a coating liquid for forming the void layer, as will be described later.

[0043] [1. Void layers, laminates, optical components, and optical devices] As described above, the void layer of the present invention is a void layer formed by chemically bonding particles together, wherein the void ratio of the void layer is 35% by volume or more, and the particles are inorganic-organic composite particles in which an organic group is bonded to an inorganic compound, and the organic group is a linear or branched alkyl group R 1 The group and the group R which contains a carbon-carbon unsaturated bond. 2 Includes the base, R 1 Base and R 2 R for the sum of the bases 2 The present invention is characterized by having a molar ratio of 1 to 30 mol%. Furthermore, the laminate of the present invention is characterized by comprising the void layer of the present invention and an adhesive layer directly laminated on one or both sides of the void layer, as described above. In the present invention, "directly laminated" of the adhesive layer to the void layer means, for example, that the adhesive layer is in direct contact with the void layer, or that the adhesive layer is laminated to the void layer via the intermediate layer.

[0044] The laminate of the present invention, after a heat-humidification durability test in which it is held at a temperature of 60°C and a relative humidity of 90% for 1000 hours, may have a void retention rate of 70% or more by volume, 80% or more by volume, or 83% or more by volume compared to the voids before the heat-humidification durability test. The upper limit is not particularly limited, but ideally it is 100% by volume, and may be 99% or less by volume, 98% or less by volume, or 95% or less by volume.

[0045] If the laminate of the present invention has the intermediate layer, for example, after a heat and humidification durability test in which the intermediate layer is held at a temperature of 60°C and a relative humidity of 90% for 1000 hours, the increase in the thickness of the intermediate layer may be 500% or less compared to the thickness of the intermediate layer before the heat and humidification durability test, with the thickness of the intermediate layer before the heat and humidification durability test being set to 100%. The increase in the thickness of the intermediate layer after the heat and humidification durability test may be, for example, 500% or less, 400% or less, or 300% or less compared to the thickness of the intermediate layer before the heat and humidification durability test, with the thickness of the intermediate layer before the heat and humidification durability test being set to 100%, and may also be, for example, 110% or more, 120% or more, 130% or more, or 150% or more.

[0046] Furthermore, the void retention rate of the void layer after the heat-humidification durability test of the present invention may be 80% or more, 85% or more, or 88% or more of the void retention rate when only the void layer is subjected to the heat-humidification durability test, or it may be 99% or less, 98% or less, or 97% or less.

[0047] In the present invention, the light transmittance of the void layer or the laminate of the present invention may be 80% or more. Also, for example, the haze of the void layer or the laminate of the present invention may be 3% or less. The light transmittance may be, for example, 82% or more, 84% or more, 86% or more, or 88% or more, and there is no particular upper limit, but ideally it is 100%, and for example it may be 95% or less, 92% or less, 91% or less, or 90% or less. The haze of the void layer or the laminate of the present invention can be measured, for example, by the haze measurement method described later. The light transmittance is the transmittance of light with a wavelength of 550 nm, and can be measured, for example, by the following measurement method.

[0048] (Method for measuring light transmittance) Using a spectrophotometer U-4100 (product name of Hitachi, Ltd.), the laminate is used as the sample to be measured. The total light transmittance (light transmittance) of the sample is then measured, with the total light transmittance of air set to 100%. The value of the total light transmittance (light transmittance) is defined as the measurement taken at a wavelength of 550 nm.

[0049] The laminate of the present invention may have, for example, an adhesive strength or bonding strength of the adhesive layer of the adhesive layer of, for example, 0.7 N / 25 mm or more, 0.8 N / 25 mm or more, 1.0 N / 25 mm or more, or 1.5 N / 25 mm or more, or 50 N / 25 mm or less, 30 N / 25 mm or less, 10 N / 25 mm or less, 5 N / 25 mm or less, or 3 N / 25 mm or less. From the viewpoint of the risk of peeling during handling when the laminate is bonded to other layers, it is preferable that the adhesive strength or bonding strength of the adhesive layer is not too low. Also, from the viewpoint of rework when re-bonding, it is preferable that the adhesive strength or bonding strength of the adhesive layer is not too high. The adhesive strength or bonding strength of the adhesive layer can be measured, for example, as follows.

[0050] (Method for measuring adhesive strength or bonding strength) A sample of the laminated film of the present invention (a laminate of the present invention formed on a resin film substrate) is taken in the form of a 50 mm x 140 mm strip, and the sample is fixed to a stainless steel plate with double-sided tape. An acrylic adhesive layer (20 μm thick) is laminated to a PET film (T100: manufactured by Mitsubishi Plastics Film Co., Ltd.), and a piece of adhesive tape cut to 25 mm x 100 mm is attached to the side of the laminated film of the present invention opposite to the resin film, and the PET film is laminated. Next, the sample is chucked into an Autograph tensile tester (manufactured by Shimadzu Corporation: AG-Xplus) with a chuck distance of 100 mm, and a tensile test is performed at a tensile speed of 0.3 m / min. The average test force obtained from the 50 mm peel test is defined as the adhesive peel strength, i.e., the adhesive force. The bonding force can also be measured using the same measurement method. In the present invention, there is no clear distinction between "adhesion force" and "bonding force".

[0051] The laminate of the present invention may be formed on a substrate such as a film. The film may be, for example, a resin film. Generally, materials with relatively small thickness are called "films" and those with relatively large thickness are called "sheets" to distinguish them, but in the present invention, there is no particular distinction between "films" and "sheets".

[0052] The substrate is not particularly limited, and preferably, but is not limited to, a thermoplastic resin substrate, a glass substrate, an inorganic substrate such as silicon, a plastic molded from a thermosetting resin, a semiconductor or other element, a carbon fiber material such as carbon nanotubes, etc. The form of the substrate may be, for example, a film, a plate, etc. The thermoplastic resin may be, for example, polyethylene terephthalate (PET), acrylic, cellulose acetate propionate (CAP), cycloolefin polymer (COP), triacetylcellulose (TAC), polyethylene naphthalate (PEN), polyethylene (PE), polypropylene (PP), etc.

[0053] The optical component of the present invention is not particularly limited, but may be, for example, an optical film including the laminate of the present invention.

[0054] The optical device of the present invention is not particularly limited, but may be, for example, an image display device or an illumination device. Examples of image display devices include liquid crystal displays, organic EL (Electro Luminescence) displays, and micro-LED (Light Emitting Diode) displays. Examples of illumination devices include organic EL lighting.

[0055] [2.Void layer] The void layer in the laminate of the present invention (hereinafter sometimes referred to as "the void layer of the present invention") will be described below with examples. However, the void layer of the present invention is not limited to these examples.

[0056] The void layer of the present invention may, for example, have a porosity of 35 volume% or more and a peak pore diameter of 50 nm or less. However, this is illustrative, and the void layer of the present invention is not limited thereto.

[0057] The porosity may be, for example, 35 volume% or more, 38 volume% or more, or 40 volume% or more, and may be 90 volume% or less, 80 volume% or less, or 75 volume% or less. The void layer of the present invention may be, for example, a high void layer with a porosity of 60 volume% or more.

[0058] The aforementioned porosity can be measured, for example, by the following measurement method.

[0059] (Method for measuring void ratio) If the layer being measured for porosity is a single layer containing only voids, the ratio (volume ratio) of the layer's constituent material to air can be calculated using standard methods (for example, by measuring weight and volume to calculate density), and thus the porosity (volume %) can be calculated. Furthermore, since there is a correlation between refractive index and porosity, the porosity can also be calculated from the refractive index value of the layer, for example. Specifically, the porosity can be calculated from the refractive index value measured with an ellipsometer using the Lorentz-Lorenz formula.

[0060] The void layer of the present invention can be manufactured, for example, by chemical bonding of gel pulverized material (microporous particles), as described later. In this case, for convenience, the voids in the void layer can be divided into three types as follows: (1) to (3). (1) The voids present in the raw material gel itself (within the particles) (2) Voids in the gel pulverized material units (3) Voids between the pulverized material caused by the accumulation of the pulverized gel

[0061] The voids in (2) above are voids formed during grinding, separate from those in (1), that can be formed within each block when each group of particles generated by grinding the gel is considered as a single block, regardless of the size, dimensions, etc., of the gel pulverized material (microporous particles). Furthermore, the voids in (3) above are voids that occur during grinding (e.g., medialess grinding) due to the uneven size, dimensions, etc., of the gel pulverized material (microporous particles). The void layer of the present invention has, for example, voids in (1) to (3) above, thereby having an appropriate porosity and peak pore diameter.

[0062] Furthermore, the peak pore diameter may be, for example, 5 nm or more, 10 nm or more, or 20 nm or more, or 50 nm or less, 40 nm or less, or 30 nm or less. In the void layer, if the peak pore diameter is too large when the porosity is high, light is scattered and the layer becomes opaque. Also, in the present invention, the lower limit of the peak pore diameter of the void layer is not particularly limited, but if the peak pore diameter is too small, it becomes difficult to increase the porosity, so it is preferable that the peak pore diameter is not too small. In the present invention, the peak pore diameter can be measured, for example, by the following method.

[0063] (Method for measuring peak pore size) Using a pore distribution / specific surface area analyzer (BELLSORP MINI / product name of Microtrac Bell), the peak pore diameter is calculated from the results obtained by calculating BJH plots and BET plots due to nitrogen adsorption, as well as isothermal adsorption curves.

[0064] Furthermore, as described above, the void layer of the present invention is a void layer formed by chemically bonding particles together. As described above, the particles are inorganic-organic composite particles in which an organic group is bonded to an inorganic compound, and the organic group is a linear or branched alkyl group. 1 The group and the group R which contains a carbon-carbon unsaturated bond. 2 Includes the base, R 1 Base and R 2 R for the sum of the bases 2 The molar ratio of the base is 1 to 30 mol%. The particles contain the R 1 base and R2 The method for incorporating the group will be described in detail later.

[0065] Furthermore, as described above, the void layer of the present invention may contain nanoparticles surface-modified with a surface-oriented compound. The nanoparticles will be described in detail later. The void layer of the present invention may contain the nanoparticles in an amount of, for example, 10-50% by mass, 15-40% by mass, or 20-30% by mass relative to the skeletal component of the void layer. In the void layer of the present invention, the "skeletal component" refers to the component with the largest mass among the components other than air that form the void layer of the present invention. If the void layer of the present invention is a silicone porous material, the "skeletal component" is, for example, a condensation product of monoalkyl(trimethoxy)silane.

[0066] Furthermore, the thickness of the void layer in the present invention is not particularly limited, but may be, for example, 100 nm or more, 200 nm or more, or 300 nm or more, or 10,000 nm or less, 5,000 nm or less, or 2,000 nm or less.

[0067] In the present invention, the void layer is formed by using pulverized porous gel, for example, as described later, which destroys the three-dimensional structure of the porous gel and creates a new three-dimensional structure different from that of the porous gel. Thus, the void layer of the present invention has a new pore structure (new void structure) that cannot be obtained from a layer formed from the porous gel, making it possible to form a nanoscale void layer with a high porosity. Furthermore, in the present invention, for example, if the void layer is a silicone porous material, the pulverized material is chemically bonded to itself while adjusting the number of siloxane bond functional groups in the silicon compound gel, for example. Also, since the new three-dimensional structure is formed as a precursor to the void layer and then chemically bonded (e.g., crosslinked) in the bonding process, the void layer of the present invention, for example, if the void layer is a functional porous material, has a void structure but can maintain sufficient strength and flexibility. Therefore, according to the present invention, a void layer can be easily and simply applied to various objects.

[0068] The void layer of the present invention, for example, contains pulverized porous gel, as described later, and the pulverized material is chemically bonded to itself. In the void layer of the present invention, the form of the chemical bond between the pulverized material is not particularly limited, and specific examples of the chemical bond include, for example, cross-linking. The method for chemically bonding the pulverized material is described in detail later in the method for manufacturing the void layer.

[0069] The aforementioned crosslinking bond is, for example, a siloxane bond. Examples of siloxane bonds include the T2 bond, T3 bond, and T4 bond shown below. When the porous silicone material of the present invention has siloxane bonds, it may have, for example, any one type of bond, any two types of bonds, or all three types of bonds. The higher the ratio of T2 and T3 among the siloxane bonds, the more flexible the material becomes and the more the gel's inherent properties can be expected, but the film strength becomes weaker. On the other hand, if the ratio of T4 among the siloxane bonds is high, film strength is easily achieved, but the void size becomes smaller and the flexibility becomes brittle. For this reason, it is preferable to change the ratio of T2, T3, and T4 depending on the application, for example.

[0070] [ka]

[0071] When the void layer of the present invention has the siloxane bond, the ratios of T2, T3, and T4 are, for example, expressed relatively with T2 as "1", T2:T3:T4 = 1:[1~100]:[0~50], 1:[1~80]:[1~40], and 1:[5~60]:[1~30].

[0072] Furthermore, it is preferable that the void layer of the present invention contains silicon atoms bonded together by siloxane bonds. Specifically, the proportion of unbonded silicon atoms (i.e., residual silanols) among the total silicon atoms contained in the porous silicone material is, for example, less than 50%, 30% or less, or 15% or less.

[0073] The void layer of the present invention has, for example, a pore structure. In the present invention, the void size of the pore refers to the diameter of the major axis of the void (pore) among the diameter of the major axis and the diameter of the minor axis. The void size is, for example, 5 nm to 50 nm. The lower limit of the void size is, for example, 5 nm or more, 10 nm or more, or 20 nm or more, and the upper limit is, for example, 50 nm or less, 40 nm or less, or 30 nm or less, and the range is, for example, 5 nm to 50 nm or 10 nm to 40 nm. The preferred void size is determined according to the application in which the void structure is used, so for example, it is necessary to adjust it to the desired void size according to the purpose. The void size can be evaluated by, for example, the following method.

[0074] (Cross-sectional SEM observation of the void layer) In this invention, the morphology of the void layer can be observed and analyzed using a scanning electron microscope (SEM). Specifically, for example, the void layer can be processed using FIB under cooling (acceleration voltage: 30kV), and a cross-sectional electron image can be obtained from the resulting cross-sectional sample using a FIB-SEM (FEI Corporation: product name Helios NanoLab600, acceleration voltage: 1kV) at an observation magnification of 100,000x.

[0075] (Evaluation of void size) In the present invention, the void size can be quantified by the BET test method. Specifically, 0.1 g of the sample (void layer of the present invention) is placed in the capillary of a pore distribution / specific surface area measuring device (BELLSORP MINI / product name of Microtrac Bell), and then dried under reduced pressure at room temperature for 24 hours to degas the gas within the void structure. Then, nitrogen gas is adsorbed onto the sample to create BET plots, BJH plots, and adsorption isotherms, and the pore distribution is determined. This allows the void size to be evaluated.

[0076] The void layer of the present invention may, for example, have a porous structure as described above, or it may be a continuous cell structure in which the porous structure is continuous. The continuous cell structure means, for example, that the porous structure is connected three-dimensionally in the void layer, and can also be said to be a state in which the internal voids of the porous structure are continuous. When a porous body has a continuous cell structure, it is possible to increase the porosity in the bulk, but when using closed-cell particles such as hollow silica, a continuous cell structure cannot be formed. In contrast, the void layer of the present invention has a three-dimensional dendritic structure in the sol particles (pulverized porous gel that forms the sol), so the dendritic particles settle and accumulate in the coating film (a coating film of sol containing the pulverized porous gel), making it possible to easily form a continuous cell structure. Furthermore, it is preferable that the void layer of the present invention forms a monolithic structure in which the continuous cell structure has a plurality of pore distributions. The monolithic structure refers to, for example, a hierarchical structure in which a structure with nano-sized fine voids exists and a continuous cell structure in which these nano-voids are aggregated. When forming the aforementioned monolithic structure, for example, it is possible to achieve both film strength and high porosity by providing fine voids while simultaneously providing high porosity with coarse interconnected voids. To form such monolithic structures, for example, it is important to first control the pore distribution of the void structure generated in the porous gel before it is ground into the pulverized material. Furthermore, for example, when grinding the porous gel, the monolithic structure can be formed by controlling the particle size distribution of the pulverized material to a desired size.

[0077] In the void layer of the present invention, the haze exhibiting transparency is not particularly limited, with a lower limit of, for example, 0.1% or more, 0.2% or more, or 0.3% or more, and an upper limit of, for example, 10% or less, 5% or less, or 3% or less, and a range of, for example, 0.1 to 10%, 0.2 to 5%, or 0.3 to 3%.

[0078] The aforementioned haze can be measured, for example, by the following method.

[0079] (Hayes's evaluation) The void layer (the void layer of the present invention) is cut to a size of 50 mm x 50 mm and set in a haze meter (HM-150, manufactured by Murakami Color Technology Research Institute Co., Ltd.) to measure the haze. The haze value is calculated using the following formula. Haze (%) = [Diffuse transmittance (%) / Total light transmittance (%)] × 100 (%)

[0080] The refractive index of a medium is generally defined as the ratio of the propagation speed of the wavefront of light in a vacuum to the propagation speed within the medium. The refractive index of the void layer of the present invention is not particularly limited, and its upper limit is, for example, 1.3 or less, less than 1.3, 1.25 or less, 1.2 or less, and 1.15 or less, and its lower limit is, for example, 1.05 or more, 1.06 or more, and 1.07 or more, and its range is, for example, 1.05 or more and 1.3 or less, 1.05 or more and less than 1.3, 1.05 or more and 1.25 or less, 1.06 or more and less than 1.2, and 1.07 or more and 1.15 or less.

[0081] In this invention, unless otherwise specified, the refractive index refers to the refractive index measured at a wavelength of 550 nm. Furthermore, the method for measuring the refractive index is not particularly limited and can be measured, for example, by the following method.

[0082] (Evaluation of refractive index) After forming a void layer (the void layer of the present invention) on an acrylic film, it is cut to a size of 50 mm x 50 mm and bonded to the surface of a glass plate (thickness: 3 mm) with an adhesive layer. The center of the back surface of the glass plate (approximately 20 mm in diameter) is painted with black ink to prepare a sample that does not reflect off the back surface of the glass plate. The sample is placed in an ellipsometer (JAWoollam Japan: VASE), and the refractive index is measured under conditions of a wavelength of 500 nm and an incident angle of 50 to 80 degrees, and the average value is taken as the refractive index.

[0083] The thickness of the void layer in the present invention is not particularly limited, with a lower limit of, for example, 0.05 μm or more and 0.1 μm or more, and an upper limit of, for example, 1000 μm or less and 100 μm or less, and a range of, for example, 0.05 to 1000 μm and 0.1 to 100 μm.

[0084] The form of the void layer in the present invention is not particularly limited and may be, for example, a film shape or a block shape.

[0085] The method for manufacturing the void layer of the present invention is not particularly limited, but it can be manufactured, for example, by the manufacturing method described later.

[0086] [3.R 1 base and R 2 basis] As described above, the void layer of the present invention is a void layer formed by chemically bonding particles together. As described above, the particles are inorganic-organic composite particles in which an organic group is bonded to an inorganic compound, and the organic group is a linear or branched alkyl group. 1 The group and the group R which contains a carbon-carbon unsaturated bond. 2 Includes the base, R 1 Base and R 2 R for the sum of the bases 2 The molar ratio of the base is 1 to 30 mol%. 1 Base and R 2 R for the sum of the bases 2 The molar ratio of the base may be, for example, 30 mol% or less, 25 mol% or less, or 10 mol% or less, and may also be, for example, 1 mol% or more, 1.5 mol% or more, 1.8 mol% or more, 2 mol% or more, or 2.5 mol% or more. The molar ratio is determined by solid-state NMR ( 1 Using H-NMR, R 1 Proton peaks originating from the group and R 2 This can be determined by comparing the intensities of the proton peaks originating from the group.

[0087] The aforementioned R 1 The group is not particularly limited, but examples include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, sec-butyl group, tert-butyl group, etc. 2 The base is not particularly limited, but for example, it is as described above.

[0088] The R 1 base and R 2As a method for incorporating the group, for example, the R is used as part or all of the raw materials when manufacturing the particles. 1 base and the R 2 Any compound having the group may be used. Also, for example, as part or all of the above raw materials, the R 1 base and the R 2 In addition to or instead of the compound having the group, the R 1 A compound having a group and the R 2 Compounds having the group may also be used. 1 base and the R 2 The compound having the group is not particularly limited, but for example, a combination of methyltrimethoxysilane and vinyltrimethoxysilane can be mentioned. 1 The base has a methyl group, and vinyltrimethoxysilane is R 2 It is a compound having a vinyl group as a base. 1 base and the R 2 Other combinations of compounds having the group include, for example, a combination of methyltrimethoxysilane and allyltrimethoxysilane, a combination of methyltrimethoxysilane and 3-(acrylooxy)propyltrimethoxysilane, a combination of methyltriethoxysilane and allyltrimethoxysilane, a combination of methyltriethoxysilane and 3-(acrylooxy)propyltrimethoxysilane, a combination of methyltriethoxysilane and vinyltrimethoxysilane, a combination of methyltrimethoxysilane and allyltriethoxysilane, a combination of methyltrimethoxysilane and 3-(acrylooxy)propyltriethoxysilane, a combination of methyltrimethoxysilane and vinyltriethoxysilane, and so on. 1 The compound having the group is not particularly limited, but examples include methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, n-propyltrimethoxysilane, n-propyltriethoxysilane, isopropyltrimethoxysilane, isopropyltriethoxysilane, and the like. 2The compounds having a group are not particularly limited. For example, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, 3-(acryloyloxy)propyltrimethoxysilane, 3-(acryloyloxy)propyltriethoxysilane, methylvinyldimethoxysilane, methylvinyldiethoxysilane, vinyltriisopropoxysilane, vinyltris(2-methoxyethoxy)silane, tris(trimethylsiloxy)vinylsilane, dimethylethoxyvinylsilane, trimethoxy(7-octen-1-yl)silane, 3-[dimethoxy(methyl)silyl]propyl methacrylate, 3-(methoxydimethylsilyl)propyl acrylate, 3-(trimethoxysilyl)propyl methacrylate, 3-(triethoxysilyl)propyl methacrylate, 3-[dimethoxy(methyl)silyl]propyl acrylate, [dimethoxy(methyl)silyl]methyl methacrylate, (triethoxysilyl)methyl methacrylate, etc. may be mentioned. The content of the compound having the R 1 group and the compound having the R 2 group, the compound having the R 1 group, the compound having the R 2 group in the raw material is not particularly limited. For example, it may be appropriately set so that the content of the R 1 group and the R 2 group in the particles becomes suitable. The content of the compound having the R 2 group in the raw material is not particularly limited. However, based on the total mass of the compound having the R 1 group and the compound having the R 2 group, for example, it may be 30% by mass or less, 20% by mass or less, or 10% by mass or less, and for example, it may be 1% by mass or more, 1.5% by mass or more, 1.8% by mass or more, or 2% by mass or more. Also, it may contain components other than the compound having the R 1 group and the compound having the R 2 group.

[0089] [4. Nanoparticles surface-modified with a compound having surface orientation] As described above, the void layer of the present invention may contain a compound having surface orientation.

[0090] The surface-oriented compound may, for example, contain a fluoroalkyl group having 5 to 17 or 5 to 10 fluorine atoms. The fluoroalkyl group may be an alkyl group in which only some hydrogen atoms are substituted with fluorine, or an alkyl group in which all hydrogen atoms are substituted with fluorine (perfluoroalkyl group). Furthermore, the fluoroalkyl group may be a fluoroalkyl group that includes a perfluoroalkyl group as part of its structure. The alkyl group in the fluoroalkyl group is not particularly limited, but examples include linear or branched alkyl groups having 2 to 10 carbon atoms.

[0091] Furthermore, as mentioned above, for example, the compound having surface orientation may be an alkoxysilane derivative, and the alkoxysilane derivative may contain a fluoroalkyl group having 5 to 17 or 5 to 10 fluorine atoms. The fluoroalkyl group may be an alkyl group in which only some of the hydrogen atoms are substituted with fluorine, or it may be an alkyl group in which all of the hydrogen atoms are substituted with fluorine (perfluoroalkyl group). Also, the fluoroalkyl group may be a fluoroalkyl group that includes a perfluoroalkyl group as part of its structure. The alkyl group in the fluoroalkyl group is not particularly limited, but as mentioned above, for example, a linear or branched alkyl group having 2 to 10 carbon atoms can be cited.

[0092] The alkoxysilane derivative may be, for example, a derivative of monoalkoxysilane, dialkoxysilane, trialkoxysilane, or tetraalkoxysilane. More specifically, it may be a derivative in which one or more alkyl groups among the alkoxy groups in one molecule of the alkoxysilane are replaced by the fluoroalkyl group. Examples of the alkyl group in the fluoroalkyl group are as described above. Furthermore, the alkoxy group in the molecule of the alkoxysilane derivative that is not replaced by the fluoroalkyl group is not particularly limited, but examples include a linear or branched alkyl group having 1 to 4 carbon atoms, such as a methoxy group. Specific examples of the alkoxysilane derivative include trimethoxy(1H,1H,2H,2H-nonanafluorohexyl)silane, trimethoxy(1H,1H,2H,2H-heptadecafluorodecyl)silane, triethoxy[5,5,6,6,7,7,7-heptafluoro-4,4-bis(trifluoromethyl)heptyl]silane, and the like. Furthermore, while only one type of alkoxysilane derivative may be used, multiple types may be used in combination.

[0093] Furthermore, examples of compounds having surface orientation include, in addition to the alkoxysilane derivatives, surfactants that have a perfluoro group and also contain both hydrophilic and hydrophobic parts, such as a hydroxyl group or a sodium sulfonate group, at their terminal ends within a single structure.

[0094] The nanoparticles are not particularly limited, but may be silica particles, for example, or more specifically, pulverized silicon compound gels as described later. The particle size of the nanoparticles is not particularly limited, but may be, for example, 1 nm or more, 2 nm or more, 3 nm or more, or 5 nm or more, or 1000 nm or less, 500 nm or less, 200 nm or less, or 50 nm or less. The volume-average particle size can be measured, for example, by particle size distribution evaluation devices such as dynamic light scattering and laser diffraction, and by electron microscopes such as scanning electron microscopes (SEM) and transmission electron microscopes (TEM).

[0095] The method for modifying the nanoparticles with the surface-oriented compound is not particularly limited, and known methods can be used as appropriate. More specifically, for example, the nanoparticles and the surface-oriented compound may be heated in a liquid and reacted. The medium (dispersion medium) in the liquid is not particularly limited, and examples include water and alcohol, and one type or multiple types may be used in combination. Examples of alcohols include IPA (isopropyl alcohol), IBA (isobutyl alcohol), ethanol, methanol, etc., and other alcohols such as MIBK (methyl isobutyl ketone) and MEK (methyl ethyl ketone) may also be included. The reaction temperature and reaction time of the reaction are also not particularly limited and can be set as appropriate.

[0096] [5. Adhesive coating liquid] In the laminate of the present invention, the adhesive layer is not particularly limited, but for example, as described above, it can be formed using an adhesive coating liquid (hereinafter sometimes referred to as "the adhesive coating liquid of the present invention") that contains a (meth)acrylic polymer, a monomer having one or two reactive double bonds per molecule, an isocyanate crosslinking agent, and an organic peroxide. The adhesive coating liquid of the present invention can be produced, for example, by a manufacturing method that includes a mixing step of mixing the (meth)acrylic polymer, the monomer having one or two reactive double bonds per molecule, the isocyanate crosslinking agent, and the organic peroxide. In the present invention, "tack" and "adhesive" are not necessarily clearly distinguishable, as will be described later. In the present invention, "adhesive" includes both "tack" and "adhesive" unless otherwise specified. As described above, the adhesive coating liquid of the present invention contains a (meth)acrylic polymer, a monomer having one or two reactive double bonds per molecule, an isocyanate crosslinking agent, and an organic peroxide. Aside from the above, the adhesive coating liquid of the present invention is not particularly limited, but examples are given below.

[0097] The adhesive coating liquid of the present invention is, for example, a (meth)acrylic polymer in which the (meth)acrylic polymer contains 3 to 10% by weight of a heterocyclic acrylic monomer, 0.5 to 5% by weight of (meth)acrylic acid having polymerizable functional groups, 0.05 to 2% by weight of hydroxyalkyl (meth)acrylate, and 83 to 96.45% by weight of alkyl (meth)acrylate as monomer components, and this (meth)acrylic polymer is used as the base polymer.

[0098] As heterocyclic acrylic monomers, those having polymerizable functional groups and heterocyclic rings can be used without particular limitation. Examples of polymerizable functional groups include (meth)acryloyl groups and vinyl ether groups. Among these, (meth)acryloyl groups are preferred. Examples of heterocyclic rings include morpholine rings, piperidine rings, pyrrolidine rings, and piperazine rings. Examples of heterocyclic acrylic monomers include N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, and N-acryloylpyrrolidine. Among these, N-acryloylmorpholine is preferred. Heterocyclic acrylic monomers can improve the heat resistance and moisture resistance durability when the adhesive layer is thinned. In the following, N-acryloylmorpholine may be referred to as "ACMO".

[0099] Furthermore, heterocyclic acrylic monomers are preferred because they can improve the adhesion of the adhesive layer to the optical film. They are particularly preferred because they improve adhesion to cyclic polyolefins such as norbornene-based resins, and are suitable when cyclic polyolefins are used as the optical film.

[0100] The heterocyclic acrylic monomer is used, for example, in a proportion of 3 to 10% by weight relative to the total amount of monomer components forming the (meth)acrylic polymer. The proportion of heterocyclic acrylic monomer may be, for example, 4 to 9.5% by weight or 6 to 9% by weight. From the viewpoint of heat resistance and moisture resistance when the adhesive layer is thinned, it is preferable that the proportion of heterocyclic acrylic monomer is not less than the above range. Furthermore, from the viewpoint of moisture resistance when the layer is thinned, it is preferable that the proportion of heterocyclic acrylic monomer is not more than the above range. Furthermore, from the viewpoint of improving the bonding properties of the adhesive layer, it is preferable that the proportion of heterocyclic acrylic monomer is not more than the above range. Furthermore, from the viewpoint of adhesive strength, it is preferable that the proportion of heterocyclic acrylic monomer is not more than the above range.

[0101] Acrylic acid is particularly preferred as the (meth)acrylic acid.

[0102] (Meth)acrylic acid is used, for example, in a proportion of 0.5 to 5% by weight relative to the total amount of monomer components forming the (meth)acrylic polymer. The proportion of (meth)acrylic acid may be, for example, 1 to 4.5% by weight or 1.5 to 4% by weight. From the viewpoint of heat resistance when the adhesive layer is thinned, it is preferable that the proportion of (meth)acrylic acid is not less than the above range. Furthermore, from the viewpoint of heat resistance and moisture resistance when the layer is thinned, it is preferable that the proportion of (meth)acrylic acid is not more than the above range. Furthermore, from the viewpoint of adhesive strength, it is preferable that the proportion of (meth)acrylic acid is not more than the above range.

[0103] As hydroxyalkyl (meth)acrylates, for example, those having polymerizable functional groups and hydroxyl groups can be used without particular limitation. Suitable hydroxyalkyl (meth)acrylates include, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate.

[0104] Hydroxyalkyl (meth)acrylate is used, for example, in a proportion of 0.05 to 2% by weight relative to the total amount of monomer components forming the (meth)acrylic polymer. The proportion of hydroxyalkyl (meth)acrylate may be, for example, 0.075 to 1.5% by weight or 0.1 to 1% by weight. From the viewpoint of heat resistance when the adhesive layer is thinned, it is preferable that the proportion of hydroxyalkyl (meth)acrylate is not less than the above range. Furthermore, from the viewpoint of heat resistance and moisture resistance when the layer is thinned, it is preferable that the proportion of hydroxyalkyl (meth)acrylate is not more than the above range. Furthermore, from the viewpoint of adhesive strength, it is preferable that the proportion of hydroxyalkyl (meth)acrylate is not more than the above range.

[0105] As for the alkyl(meth)acrylate, for example, the average number of carbon atoms in the alkyl group of the alkyl(meth)acrylate may be about 1 to 12. Note that (meth)acrylate refers to acrylate and / or methacrylate, and the (meth) in this invention has the same meaning. Specific examples of alkyl(meth)acrylates include methyl(meth)acrylate, ethyl(meth)acrylate, n-butyl(meth)acrylate, 2-ethylhexyl(meth)acrylate, isooctyl(meth)acrylate, isononyl(meth)acrylate, lauryl(meth)acrylate, etc., and these can be used alone or in combination. Among these, alkyl(meth)acrylates with 1 to 9 carbon atoms in the alkyl group are preferred.

[0106] Alkyl (meth)acrylates are used, for example, in a proportion of 83 to 96.45% by weight relative to the total amount of monomer components forming the (meth)acrylic polymer. Alkyl (meth)acrylates are typically the remainder of the mixture other than the heterocyclic acrylic monomer, (meth)acrylic acid, and hydroxyalkyl (meth)acrylate.

[0107] As monomer components forming the (meth)acrylic polymer, for example, in addition to the monomers mentioned above, any other monomers can be used in an amount of 10% or less of the total amount of monomers, as long as they do not impair the objectives of the present invention.

[0108] Examples of the aforementioned optional monomers include acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; sulfonic acid group-containing monomers such as styrene sulfonic acid, allyl sulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid; and phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate. Nitrogen-containing vinyl monomers are also mentioned. For example, maleimide, N-cyclohexylmaleimide, N-phenylmaleimide; (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N-diethyl(meth)acrylamide, N-hexyl(meth)acrylamide, N-methyl(meth)acrylamide, N-butyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, and other (N-substituted)amide monomers; aminoethyl(meth)acrylate, aminopropyl(meth)acrylate, N,N(meth)acrylate Examples include alkylaminoalkyl monomers of (meth)acrylate such as dimethylaminoethyl (meth)acrylate, t-butylaminoethyl (meth)acrylate, and 3-(3-pyridyl)propyl (meth)acrylate; alkoxyalkyl monomers of (meth)acrylate such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; and succinimide monomers such as N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, and N-(meth)acryloyl-8-oxyoctamethylenesuccinimide.

[0109] Furthermore, vinyl monomers such as vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinyl carboxylic acid amides, styrene, α-methylstyrene, and N-vinylcaprolactam; cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; glycol-based acrylic ester monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; and acrylic acid ester monomers such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth)acrylate, and 2-methoxyethyl acrylate can also be used.

[0110] Furthermore, other copolymerizable monomers besides those mentioned above include silane monomers containing silicon atoms. Examples of silane monomers include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, 8-vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, and 10-acryloyloxydecyltriethoxysilane.

[0111] The (meth)acrylic polymer used in the present invention may have, for example, a weight-average molecular weight of 1.5 million to 2.8 million. The weight-average molecular weight may also be, for example, 1.7 million to 2.7 million or 2 million to 2.5 million. From the viewpoint of heat resistance and moisture resistance when the adhesive layer is thinned, it is preferable that the weight-average molecular weight is not smaller than the above range. Furthermore, from the viewpoint of durability when the layer is thinned, and of lamination and adhesive strength, it is preferable that the weight-average molecular weight is not larger than the above range. In the present invention, the weight-average molecular weight refers to a value calculated by GPC (gel permeation chromatography) and converted to polystyrene equivalent.

[0112] The method for producing such (meth)acrylic polymers is not particularly limited, and known production methods such as solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations can be appropriately selected. Furthermore, the resulting (meth)acrylic polymer may be a random copolymer, block copolymer, graft copolymer, or any other type.

[0113] In solution polymerization, for example, ethyl acetate and toluene are used as polymerization solvents. A specific example of solution polymerization involves adding a polymerization initiator under an inert gas stream such as nitrogen, and carrying out the reaction under conditions of approximately 50-70°C for 5-30 hours.

[0114] The polymerization initiators, chain transfer agents, and emulsifiers used in radical polymerization are not particularly limited and can be selected and used as appropriate. The weight-average molecular weight of the (meth)acrylic polymer can be controlled by the amount of polymerization initiator and chain transfer agent used and the reaction conditions, and the amount used is adjusted as appropriate depending on the type of agent.

[0115] Examples of polymerization initiators include azo-based initiators such as 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-amidinopropane)dihydrochloride, 2,2'-azobis[2-(5-methyl-2-imidazolin-2-yl)propane]dihydrochloride, 2,2'-azobis(2-methylpropionamidine)disulfate, 2,2'-azobis(N,N'-dimethyleneisobutylamidine), and 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate (manufactured by Wako Pure Chemical Industries, Ltd., VA-057), as well as persulfates such as potassium persulfate and ammonium persulfate, di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, and di-sec-butylperoxy Examples of peroxide initiators include, but are not limited to, dicarbonates, t-butyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutyl peroxy-2-ethylhexanoate, di(4-methylbenzoyl) peroxide, dibenzoyl peroxide, t-butyl peroxyisobutyrate, 1,1-di(t-hexyl peroxy)cyclohexane, t-butyl hydroperoxide, and hydrogen peroxide; as well as redox initiators combining peroxides with reducing agents, such as combinations of persulfates and sodium bisulfite, and combinations of peroxides and sodium ascorbate.

[0116] The polymerization initiator may be used alone or in a mixture of two or more. The total content of the polymerization initiator may be, for example, about 0.005 to 1 part by weight or about 0.02 to 0.5 parts by weight per 100 parts by weight of monomer.

[0117] Furthermore, when producing the (meth)acrylic polymer of the aforementioned weight-average molecular weight using, for example, 2,2'-azobisisobutyronitrile as a polymerization initiator, the amount of polymerization initiator used may be, for example, about 0.06 to 0.2 parts by weight or about 0.08 to 0.175 parts by weight per 100 parts by weight of the total amount of monomer components.

[0118] Examples of chain transfer agents include lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolate, and 2,3-dimercapto-1-propanol. The chain transfer agents may be used individually or in combination of two or more. The total content of the chain transfer agents is, for example, about 0.1 parts by weight or less per 100 parts by weight of the total amount of monomer components.

[0119] Furthermore, examples of emulsifiers used in emulsion polymerization include anionic emulsifiers such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, ammonium polyoxyethylene alkyl ether sulfate, and sodium polyoxyethylene alkylphenyl ether sulfate, and nonionic emulsifiers such as polyoxyethylene alkyl ethers, polyoxyethylene alkylphenyl ethers, polyoxyethylene fatty acid esters, and polyoxyethylene-polyoxypropylene block polymers. These emulsifiers may be used individually or in combination of two or more.

[0120] Furthermore, as reactive emulsifiers, emulsifiers incorporating radical polymerizable functional groups such as propenyl groups and allyl ether groups are specifically, for example, Aqualon HS-10, HS-20, KH-10, BC-05, BC-10, BC-20 (all manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) and Adekarya Soap SE10N (manufactured by Asahi Denka Kogyo Co., Ltd.). Reactive emulsifiers are incorporated into the polymer chain after polymerization, which improves water resistance and is therefore preferable. The amount of emulsifier used is 0.3 to 5 parts by weight, more preferably 0.5 to 1 part by weight, per 100 parts by weight of the total amount of monomer components, due to polymerization stability and mechanical stability.

[0121] The content of the (meth)acrylic polymer in the adhesive coating liquid of the present invention is not particularly limited, but may be, for example, 3% by mass or more, or 5% by mass or more, based on the total mass of the adhesive coating liquid of the present invention, or may be, for example, 30% by mass or less, 20% by mass or less, or 10% by mass or less.

[0122] Furthermore, as described above, the adhesive coating liquid of the present invention contains a monomer having one or two reactive double bonds in one molecule. The monomer having one or two reactive double bonds in one molecule is not particularly limited, but from the viewpoint of the reaction rate of the graft reaction, acrylic monomers, methacrylic monomers, vinyl monomers, and allyl monomers are preferred, and acrylic monomers are more preferred. The acrylic monomer is not particularly limited, but for example, it may be the same as the monomer exemplified as the monomer component of the (meth)acrylic polymer. In the monomer having one or two reactive double bonds in one molecule, the structure of the side chain is not particularly limited, but heterocyclic monomers are preferred because they can simultaneously achieve high modulus within an appropriate range and a reduction in the amount of semipolymer.

[0123] In the adhesive coating liquid of the present invention, the content of monomers having one or two reactive double bonds in one molecule is not particularly limited, but may be, for example, 0.1% by mass or more, 0.5% by mass or more, or 1% by mass or more, relative to the total mass of the (meth)acrylic polymer, or may be, for example, 30% by mass or less, 20% by mass or less, or 10% by mass or less.

[0124] Furthermore, as described above, the adhesive coating liquid of the present invention contains an isocyanate-based crosslinking agent. The isocyanate-based crosslinking agent is not particularly limited, but examples include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.

[0125] More specifically, the isocyanate-based crosslinking agents include, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate and isophorone diisocyanate, aromatic diisocyanates such as 2,4-tolylene diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate and polymethylene polyphenyl isocyanate, and trimethylolpropane / tolylene diisocyanate trimer adducts (Japanese Examples include isocyanate adducts such as Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.), trimethylolpropane / hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Industry Co., Ltd., product name Coronate HL), and isocyanurate derivative of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., product name Coronate HX), as well as polyether polyisocyanates, polyester polyisocyanates, and adducts of these with various polyols, and polyfunctionalized polyisocyanates with isocyanurate bonds, biuret bonds, allophanate bonds, etc.

[0126] The above-mentioned isocyanate crosslinking agents may be used alone or in mixtures of two or more types. The total content may be, for example, 0.02 to 2 parts by mass, 0.04 to 1.5 parts by mass, or 0.05 to 1 part by mass of the isocyanate crosslinking agent per 100 parts by mass of the (meth)acrylic polymer. From the viewpoint of cohesive force, the content of the isocyanate crosslinking agent is preferably 0.02 parts by mass or more, while from the viewpoint of suppressing or preventing a decrease in adhesive strength due to excessive crosslinking, it is preferably 2 parts by mass or less.

[0127] The adhesive coating liquid of the present invention may or may not contain other crosslinking agents other than isocyanate-based crosslinking agents. Examples of other crosslinking agents include organic crosslinking agents and polyfunctional metal chelates. Examples of organic crosslinking agents include epoxy-based crosslinking agents and imine-based crosslinking agents. Isocyanate-based crosslinking agents are preferred among organic crosslinking agents. A polyfunctional metal chelate is a polyvalent metal in which a polyvalent metal is covalently bonded or coordinately bonded to an organic compound. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, and Ti. Examples of atoms in the organic compound that form covalent or coordinate bonds include oxygen atoms, and examples of organic compounds include alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, and ketone compounds.

[0128] Furthermore, as described above, the adhesive coating liquid of the present invention contains an organic peroxide. The organic peroxide is not particularly limited, but examples include di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecanoate, t-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, t-butylhydroperoxide, etc., and one type may be used or multiple types may be used in combination.

[0129] In the adhesive coating liquid of the present invention, the content of the organic peroxide is not particularly limited, but may be, for example, 0.1% by mass or more, 0.5% by mass or more, 1% by mass or more, 2% by mass or more, or 2.5% by mass or more, relative to the total mass of the (meth)acrylic polymer, or for example, 20% by mass or less, 10% by mass or less, 8% by mass or less, or 6% by mass or less.

[0130] The adhesive coating liquid of the present invention may further contain a solvent or the like. The solvent is not particularly limited, but for example, the polymerization solvent used in the solution polymerization in the production of the (meth)acrylic polymer may be used as is.

[0131] Furthermore, the adhesive coating liquid of the present invention may optionally contain tackifiers, plasticizers, fillers consisting of glass fibers, glass beads, metal powders, and other inorganic powders, as well as pigments, colorants, antioxidants, UV absorbers, silane coupling agents, and various other additives as appropriate, without departing from the objectives of the present invention. It may also be an adhesive layer containing fine particles that exhibits light diffusion properties.

[0132] In the laminate of the present invention, for example, if the adhesive coating liquid of the present invention is used, it is easier to achieve both adhesive strength and resistance to penetration of the adhesive into the voids. The reason (mechanism) for this can be considered as follows. For example, by forming an adhesive layer using a specific adhesive, it is possible to achieve both adhesive strength and resistance to penetration of the adhesive into the voids. More specifically, for example, by forming an adhesive layer using the specific adhesive described above, an intermediate layer is formed by the merging of a part of the void layer and a part of the adhesive layer. Furthermore, by using the specific adhesive described above, the intermediate layer does not spread excessively even under conditions such as the heat-humidification durability test. Moreover, the intermediate layer acts as a stopper, suppressing the reduction in porosity due to the voids in the void layer being filled with the adhesive. Even if the molecular motion of the adhesive increases under heating, if the elastic modulus of the adhesive is high, the intermediate layer formed from the adhesive and the high void layer tends to act as a strong and dense stopper, suppressing the penetration of the adhesive into the high void layer. Furthermore, the main component of the adhesive coating liquid, a (meth)acrylic polymer, can undergo a crosslinking reaction with an isocyanate crosslinking agent upon heating. During this crosslinking reaction, the presence of monomers with one or two reactive double bonds per molecule and an organic peroxide, which acts as a hydrogen abstraction initiator, is thought to cause high-density crosslinking of semi-high molecular weight polymer components with a molecular weight of 10,000 or less contained in the adhesive coating liquid, thereby suppressing the penetration of components from the adhesive coating liquid into the void layer to an even higher level. In other words, semi-high molecular weight polymer components with a molecular weight of 10,000 or less tend to penetrate into the voids of the void layer due to their small molecular size, but the crosslinking reaction increases their molecular size, which is thought to suppress their penetration into the voids of the void layer. Furthermore, it is hypothesized that the presence of monomers having one or two reactive double bonds per molecule during the crosslinking reaction enables graft reactions with the (meth)acrylic polymer backbone and high-density crosslinking starting from the graft chain, thereby reducing the amount of semi-molecular-weight polymer that can become a sol component. However, these mechanisms are merely illustrative and do not limit the present invention in any way.

[0133] In the adhesive coating liquid of the present invention, the monomer preferably has one or two reactive double bonds per molecule in order to efficiently crosslink the main chains in the graft reaction.

[0134] In the present invention, "(meth)acrylic" means at least one of acrylic and methacrylic. For example, "(meth)acrylic acid" means at least one of acrylic acid and methacrylic acid. "(meth)acrylic acid ester" means at least one of acrylic acid ester and methacrylic acid ester. "(meth)methyl acrylate" means at least one of methyl acrylate and methyl methacrylate.

[0135] In the present invention, "(meth)acrylic polymer" refers to a polymer having a structure obtained by polymerizing a component that includes, for example, at least one selected from the group consisting of acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, monomer having an acryloyl group, and monomer having a methacryloyl group. The component may or may not contain substances other than at least one selected from the group consisting of acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, monomer having an acryloyl group, and monomer having a methacryloyl group.

[0136] In the present invention, "acrylic monomer" refers to a monomer that includes, for example, at least one selected from the group consisting of acrylic acid, methacrylic acid, acrylic acid ester, methacrylic acid ester, monomer having an acryloyl group, and monomer having a methacryloyl group.

[0137] In the present invention, "isocyanate-based crosslinking agent" refers to a crosslinking agent having an isocyanate group (isocyanato group) in its molecule. In the present invention, the number of isocyanate groups (isocyanato groups) in one molecule of the isocyanate-based crosslinking agent is not particularly limited, but is preferably two or more, for example, it may be two, three or four, and the upper limit is not particularly limited, but is for example 10 or less.

[0138] [6. Method for manufacturing void layers and laminates] The method for manufacturing the void layer and laminate of the present invention is not particularly limited, but can be carried out, for example, by the manufacturing method described below. However, the following description is illustrative and does not limit the present invention in any way. In the following, the method for manufacturing the void layer of the present invention may be referred to as "the method for manufacturing the void layer of the present invention."

[0139] [6-1. Method for manufacturing the void layer] The method for manufacturing the void layer of the present invention will be described below with examples. However, the method for manufacturing the void layer of the present invention is not limited in any way by the following description.

[0140] The void layer of the present invention may be formed by, for example, a silicon compound. Alternatively, the void layer of the present invention may be formed by, for example, chemical bonding between microporous particles. For example, the microporous particles may be pulverized gel. Furthermore, the void layer of the present invention may, for example, have a framework formed by chemical bonding between microporous particles, in addition to the R 1 base and R 2 It may also have a group. For example, some or all of the silicon compound may be the R 1 base and the R 2 It may also be a compound having a group. For example, as part or all of the silicon compound, the R 1 base and the R 2 In addition to or instead of the compound having the group, the R 1 A compound having a group and the R 2 Compounds having the group may also be used. 1 base and the R 2 Compound having the group, the R 1 Compound having the group, the R 2 Examples of compounds having the group are not particularly limited, but include, for example, those described above. The R in the silicon compound 1 base and the R 2 Compound having the group, the R 1Compound having the group, the R 2 The content of the compound having the group is not particularly limited, but for example, the R in the particles 1 base and the R 2 The content of the group can be set appropriately so as to be favorable. Specifically, for example, the silicon compound is R 2 The compound having the group may contain 3 to 20% by mass of vinyltrimethoxysilane. In this case, the remainder of the silicon compound (other than vinyltrimethoxysilane) is not particularly limited, but may be, for example, MTMS (methyltrimethoxysilane). The R in the silicon compound 1 The content of the compound having the group is not particularly limited, but may be, for example, 99% by mass or less, 98.5% by mass or less, or 98% by mass or less, relative to the total mass of the silicon compound, or for example, 50% by mass or more, 60% by mass or more, or 70% by mass or more. 2 The content of the compound having the group is not particularly limited, but may be, for example, 50% by mass or less, 40% by mass or less, or 30% by mass or less, relative to the total mass of the silicon compound, or for example, 1% by mass or more, 1.5% by mass or more, 1.8% by mass or more, or 2% by mass or more.

[0141] Furthermore, the void layer of the present invention may, for example, include nanoparticles surface-modified with the surface-oriented compound, in addition to the framework formed by chemical bonding between the microporous particles.

[0142] In the method for manufacturing a void layer of the present invention, for example, the gel grinding step for grinding the porous gel may be a single step, but it is preferable to divide it into multiple grinding steps. The number of grinding steps is not particularly limited, and may be two steps, three or more steps, for example.

[0143] In this invention, the shape of the "particles" (for example, particles of the pulverized gel) is not particularly limited; for example, they may be spherical, or they may be non-spherical. Furthermore, in this invention, the pulverized particles may be, for example, sol-gel bead-like particles, nanoparticles (hollow nanosilica / nanoballoon particles), nanofibers, etc.

[0144] In the present invention, for example, it is preferable that the gel is a porous gel, and it is preferable that the pulverized gel is porous, but the invention is not limited thereto.

[0145] In the present invention, the pulverized gel may consist of a structure having at least one shape, such as particulate, fibrous, or plate-like. The particulate and plate-like constituent units may consist of inorganic materials, for example. The constituent elements of the particulate constituent units may also include at least one element selected from the group consisting of Si, Mg, Al, Ti, Zn, and Zr. The structures (constituent units) that form the particulates may be solid particles or hollow particles, and specific examples include silicone particles, silicone particles with micropores, silica hollow nanoparticles, and silica hollow nanoballoons. The fibrous constituent units may be nanofibers with a diameter of nanoscale, and specific examples include cellulose nanofibers and alumina nanofibers. The plate-like constituent units may be nanoclays, and specific examples include nanosized bentonite (e.g., Kunipia F [product name]). The fibrous structural units are not particularly limited, but may be at least one fibrous material selected from the group consisting of, for example, carbon nanofibers, cellulose nanofibers, alumina nanofibers, chitin nanofibers, chitosan nanofibers, polymer nanofibers, glass nanofibers, and silica nanofibers.

[0146] In the method for producing a void layer of the present invention, the gel grinding step (for example, the plurality of grinding steps, for example, the first grinding step and the second grinding step) may be carried out in, for example, the "other solvent". Details of the "other solvent" will be described later.

[0147] In this invention, the "solvent" (for example, a solvent for gel production, a solvent for void layer production, a substitution solvent, etc.) does not necessarily have to dissolve the gel or its pulverized material; for example, the gel or its pulverized material may be dispersed or precipitated in the solvent.

[0148] The volume-average particle size of the gel after the first grinding step may be, for example, 0.5 to 100 μm, 1 to 100 μm, 1 to 50 μm, 2 to 20 μm, or 3 to 10 μm. The volume-average particle size of the gel after the second grinding step may be, for example, 10 to 1000 nm, 100 to 500 nm, or 200 to 300 nm. The volume-average particle size indicates the particle size variation of the pulverized material in the liquid containing the gel (gel-containing liquid). The volume-average particle size can be measured, for example, by particle size distribution evaluation devices such as dynamic light scattering and laser diffraction, and by electron microscopes such as scanning electron microscopes (SEM) and transmission electron microscopes (TEM).

[0149] The method for producing a void layer of the present invention includes, for example, a gelation step of gelling a block-shaped porous body in a solvent to form the gel. In this case, for example, the gel gelled by the gelation step is used in the first grinding step of the multiple grinding steps (for example, the first grinding step).

[0150] The method for producing the void layer of the present invention includes, for example, a maturation step of maturing the gelled gel in a solvent. In this case, for example, the gel after the maturation step is used in the first grinding step of the multiple grinding steps (for example, the first grinding step).

[0151] The method for producing the void layer of the present invention involves, for example, performing a solvent replacement step after the gelation step in which the solvent is replaced with another solvent. In this case, for example, the gel in the other solvent is used in the first grinding step of the multiple grinding steps (for example, the first grinding step).

[0152] In at least one of the multiple grinding steps of the method for manufacturing a void layer of the present invention (for example, at least one of the first grinding step and the second grinding step), the grinding of the porous body is controlled, for example, while measuring the shear viscosity of the liquid.

[0153] At least one of the multiple grinding steps in the method for producing the void layer of the present invention (for example, at least one of the first grinding step and the second grinding step) is performed, for example, by high-pressure medialess grinding.

[0154] In the method for producing a void layer of the present invention, the gel is, for example, a gel of a silicon compound containing at least three or fewer saturated bonded functional groups.

[0155] In the following, in the method for producing a void layer of the present invention, the gel-pulverized liquid obtained by the process including the gel-pulverization step may be referred to as "the gel-pulverized liquid of the present invention."

[0156] According to the gel pulverized material-containing liquid of the present invention, for example, a coating film can be formed, and the pulverized material in the coating film can be chemically bonded to each other, thereby forming the void layer of the present invention as a functional porous material. According to the gel pulverized material-containing liquid of the present invention, for example, the void layer of the present invention can be applied to various objects. Therefore, the gel pulverized material-containing liquid of the present invention and its manufacturing method are useful, for example, in the production of the void layer of the present invention.

[0157] The gel-containing liquid of the present invention has, for example, extremely excellent uniformity, so when the void layer of the present invention is applied to applications such as optical components, its appearance can be improved.

[0158] The gel-containing liquid of the present invention may be, for example, a gel-containing liquid used to obtain a layer (void layer) having a high porosity by coating the gel-containing liquid onto a substrate and then drying it. Alternatively, the gel-containing liquid of the present invention may be, for example, a gel-containing liquid used to obtain a highly porous body (a bulk body with a large thickness or in the form of a solid block). The bulk body can be obtained, for example, by performing bulk film formation using the gel-containing liquid.

[0159] For example, a void layer of the present invention having a high void ratio can be produced by a manufacturing method that includes the steps of: producing a gel pulverized material-containing liquid of the present invention; adding nanoparticles surface-modified with the surface-oriented compound to the gel pulverized material-containing liquid; coating the mixture onto a substrate to form a coating film; and drying the coating film.

[0160] Furthermore, for example, a laminated film (laminated film roll) in the form of a roll can be manufactured, as shown in Figures 2 and 3 described later, by a manufacturing method that includes the steps of: manufacturing the gel pulverized material-containing liquid of the present invention; unwinding the roll-shaped resin film; coating the unwinded resin film with the gel pulverized material-containing liquid to form a coating film; drying the coating film; and, after the drying step, winding up the laminated film in which the void layer of the present invention has been formed on the resin film.

[0161] [5-2. Liquid containing pulverized gel and method for producing the same] The gel pulverized liquid of the present invention comprises, for example, the pulverized gel obtained by the gel pulverization process (for example, the first pulverization step and the second pulverization step) and the other solvent.

[0162] The method for manufacturing a void layer of the present invention may include, for example, a plurality of gel grinding steps for grinding the gel (for example, a porous gel), as described above, and may include, for example, a first grinding step and a second grinding step. Hereinafter, the method for manufacturing a gel-grinding-containing liquid of the present invention will be mainly described using the case in which the method includes a first grinding step and a second grinding step as an example.Hereinafter, the case in which the gel is a porous material (porous gel) will be mainly described.However, the present invention is not limited thereto, and the description in which the gel is a porous material (porous gel) can be applied by analogy to cases other than when the gel is a porous material.Also, hereafter, the plurality of grinding steps in the method for manufacturing a void layer of the present invention (for example, the first grinding step and the second grinding step) may be collectively referred to as the "gel grinding step".

[0163] The gel pulverized material-containing liquid of the present invention can be used, for example, to manufacture a functional porous body that exhibits a function similar to an air layer (e.g., low refractive index), as described later. The functional porous body may be, for example, the void layer of the present invention. Specifically, the gel pulverized material-containing liquid obtained by the manufacturing method of the present invention contains pulverized porous gel, and the pulverized material destroys the three-dimensional structure of the unpulverized porous gel, forming a new three-dimensional structure different from that of the unpulverized porous gel. For this reason, for example, a coating film (precursor of a functional porous body) formed using the gel pulverized material-containing liquid becomes a layer in which a new pore structure (new void structure) is formed that cannot be obtained in a layer formed using the unpulverized porous gel. As a result, the layer can exhibit a function similar to an air layer (e.g., similar low refractive index). Furthermore, the gel pulverized material-containing liquid of the present invention can, for example, chemically bond the pulverized material together after a new three-dimensional structure has been formed as the coating film (precursor of a functional porous body) by the inclusion of residual silanol groups in the pulverized material. As a result, the formed functional porous material has a void structure, but maintains sufficient strength and flexibility. Therefore, according to the present invention, a functional porous material can be easily and simply applied to various objects. The gel pulverized material-containing liquid obtained by the manufacturing method of the present invention is very useful, for example, in the manufacture of the porous structure which can serve as a substitute for an air layer. Furthermore, in the case of the air layer, it was necessary to form an air layer between members by stacking members with a gap between them, for example, by interposing a spacer or the like. However, the functional porous material formed using the gel pulverized material-containing liquid of the present invention can perform the same function as the air layer simply by placing it in the desired location. Therefore, as described above, it is possible to easily and simply apply the same function as the air layer to various objects than by forming the air layer.

[0164] The gel-containing liquid of the present invention can also be, for example, a solution for forming the functional porous body, or a solution for forming a void layer or a low refractive index layer. In the gel-containing liquid of the present invention, the porous body is the gel-containing liquid.

[0165] In the gel pulverized material-containing liquid of the present invention, the volume-average particle diameter range of the pulverized material (porous gel particles) is, for example, 10 to 1000 nm, 100 to 500 nm, or 200 to 300 nm. The volume-average particle diameter indicates the particle size variation of the pulverized material in the gel pulverized material-containing liquid of the present invention. As described above, the volume-average particle diameter can be measured by, for example, a particle size distribution evaluation device such as dynamic light scattering or laser diffraction, and an electron microscope such as a scanning electron microscope (SEM) or transmission electron microscope (TEM).

[0166] Furthermore, in the gel-containing liquid of the present invention, the gel concentration of the pulverized material is not particularly limited, for example, particles with a particle size of 10 to 1000 nm can be 2.5 to 4.5% by weight, 2.7 to 4.0% by weight, or 2.8 to 3.2% by weight.

[0167] In the gel-containing liquid of the present invention, the gel (for example, a porous gel) is not particularly limited and can be, for example, a silicon compound.

[0168] The silicon compound is not particularly limited, but examples include silicon compounds containing at least three or fewer saturated bonded functional groups. The phrase "containing three or fewer saturated bonded functional groups" means that the silicon compound has three or fewer functional groups, and these functional groups are saturated bonded to silicon (Si).

[0169] The silicon compound is, for example, a compound represented by the following formula (2). [ka]

[0170] In equation (2) above, for example, X is 2, 3, or 4, R 1 and R 2 These are, respectively, linear or branched alkyl groups. R 1 and R 2 They may be the same or different. R 1When X is 2, they may be the same or different from each other. R 2 They may be the same or different from each other.

[0171] The aforementioned X and R 1 For example, X and R in equation (1) described later. 1 It is the same as R 2 For example, R in equation (1) described later. 1 The example above can be used as a reference.

[0172] In addition, as a silicon compound, for example, in addition to or instead of the silicon compound represented by formula (2) above, the R as described above may be used. 1 base and the R 2 Compounds having a group may also be used. For example, as mentioned above, R 1 base and the R 2 In addition to or instead of the compound having the group, the R 1 A compound having a group and the R 2 Compounds having a group may also be used.

[0173] Specific examples of silicon compounds represented by formula (2) include, for example, the compound shown in formula (2') below, where X is 3. In formula (2') below, R 1 and R 2 These are the same as in equation (2) above. R 1 and R 2 When the group is a methyl group, the silicon compound is trimethoxy(methyl)silane (hereinafter also referred to as "MTMS"). [ka]

[0174] In the gel pulverized material-containing liquid of the present invention, the solvent can be, for example, a dispersion medium. The dispersion medium (hereinafter also referred to as the "coating solvent") is not particularly limited and can be, for example, a gelling solvent and a pulverizing solvent as described later, and is preferably the pulverizing solvent. The coating solvent includes an organic solvent having a boiling point of 70°C or higher and less than 180°C, and a saturated vapor pressure of 15 kPa or less at 20°C.

[0175] Examples of the aforementioned organic solvents include carbon tetrachloride, 1,2-dichloroethane, 1,1,2,2-tetrachloroethane, trichloroethylene, isobutyl alcohol, isopropyl alcohol, isopentyl alcohol, 1-pentyl alcohol (pentanol), ethyl alcohol (ethanol), ethylene glycol monoethyl ether, ethylene glycol monoethyl ether acetate, ethylene glycol mono-n-butyl ether, ethylene glycol monomethyl ether, xylene, cresol, chlorobenzene, isobutyl acetate, isopropyl acetate, isopentyl acetate, ethyl acetate, n-butyl acetate, n-propyl acetate, n-pentyl acetate, cyclohexanol, cyclohexanone, 1,4-dioxane, N,N-dimethylformamide, styrene, tetrachloroethylene, 1,1,1-trichloroethane, toluene, 1-butanol, 2-butanol, methyl isobutyl ketone, methyl ethyl ketone, methylcyclohexanol, methylcyclohexanone, methyl-n-butyl ketone, isopentanol, and the like. Furthermore, the dispersion medium may contain an appropriate amount of perfluoro surfactants, silicone surfactants, etc., that reduce surface tension.

[0176] The gel pulverized material-containing liquid of the present invention can be, for example, a sol particle liquid which is the sol-like pulverized material dispersed in the dispersion medium. The gel pulverized material-containing liquid of the present invention can be used, for example, to coat and dry on a substrate, and then chemically crosslinked by a bonding process described later, thereby enabling the continuous formation of a void layer having a film strength of a certain level or higher. In this invention, "sol" refers to a state in which the three-dimensional structure of the gel is pulverized, and the pulverized material (i.e., particles of a porous sol with a nano-three-dimensional structure that retains part of the void structure) is dispersed in a solvent and exhibits fluidity.

[0177] The gel pulverized material-containing liquid of the present invention may, for example, contain a catalyst for chemically bonding the gel pulverized material together. The content of the catalyst is not particularly limited, but is, for example, 0.01 to 20% by weight, 0.05 to 10% by weight, or 0.1 to 5% by weight relative to the weight of the gel pulverized material.

[0178] Furthermore, the gel pulverized material-containing liquid of the present invention may also contain, for example, a crosslinking aid for indirectly bonding the gel pulverized materials together. The content of the crosslinking aid is not particularly limited, but for example, it may be 0.01 to 20% by weight, 0.05 to 15% by weight, or 0.1 to 10% by weight relative to the weight of the gel pulverized material.

[0179] Furthermore, in the gel pulverized liquid of the present invention, the proportion of functional groups of the constituent unit monomers of the gel that do not contribute to the crosslinking structure within the gel may be, for example, 30 mol% or less, 25 mol% or less, 20 mol% or less, 15 mol% or less, or for example, 1 mol% or more, 2 mol% or more, 3 mol% or more, or 4 mol% or more. The proportion of functional groups that do not contribute to the crosslinking structure within the gel can be measured, for example, as follows.

[0180] (Method for measuring the proportion of functional groups that do not contribute to the cross-linking structure within the gel) After drying the gel, solid-state NMR (Si-NMR) is measured, and the proportion of residual silanol groups (functional groups that do not contribute to the cross-linking structure within the gel) that do not contribute to the cross-linking structure is calculated from the NMR peak ratio. Even if the functional group is not a silanol group, the proportion of functional groups that do not contribute to the cross-linking structure within the gel can be calculated similarly from the NMR peak ratio.

[0181] The method for producing the gel-containing liquid of the present invention will be described below with examples. Unless otherwise specified, the following description can be applied to the gel-containing liquid of the present invention.

[0182] In the method for producing a gel-containing liquid of the present invention, the mixing step is a step of mixing the porous gel particles (pulverized material) with the solvent, and may or may not be included. A specific example of the mixing step is a step of mixing a pulverized gel of a silicon compound (silicon compound gel) obtained from a silicon compound containing at least three or fewer saturated bonded functional groups with a dispersion medium. In the present invention, the pulverized porous gel can be obtained from the porous gel by a gel pulverization step described later. Alternatively, the pulverized porous gel can be obtained, for example, from the porous gel after an aging treatment by an aging step described later.

[0183] In the method for producing a gel-containing liquid of the present invention, the gelation step is, for example, a step of gelling a bulky porous body in a solvent to form a porous body gel. A specific example of the gelation step is, for example, a step of gelling a silicon compound containing at least three or fewer saturated bonded functional groups in a solvent to produce a silicon compound gel.

[0184] In the following, the gelation process will be explained using the case where the porous material is a silicon compound as an example.

[0185] The gelation step is, for example, a step of gelling the monomer silicon compound by a dehydration condensation reaction in the presence of a dehydration condensation catalyst, thereby obtaining a silicon compound gel. The silicon compound gel has, for example, residual silanol groups, and it is preferable to adjust the residual silanol groups as appropriate according to the chemical bonding between the pulverized silicon compound gels, which will be described later.

[0186] In the gelation step, the silicon compound is not particularly limited and can be any compound that gels through a dehydration condensation reaction. Through the dehydration condensation reaction, for example, bonds are formed between the silicon compounds. The bonds between the silicon compounds are, for example, hydrogen bonds or intermolecular force bonds.

[0187] Examples of the silicon compounds include those represented by the following formula (1). Since the silicon compounds of formula (1) have hydroxyl groups, hydrogen bonds or intermolecular force bonds can be formed between the silicon compounds of formula (1), for example, via their respective hydroxyl groups.

[0188] [ka]

[0189] In equation (1) above, for example, X is 2, 3 or 4, and R 1 is a linear or branched alkyl group. 1 The number of carbon atoms is, for example, 1-6, 1-4, or 1-2. Examples of the linear alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, etc., and examples of the branched alkyl group include an isopropyl group, an isobutyl group, etc. X is, for example, 3 or 4.

[0190] Specific examples of silicon compounds represented by formula (1) include, for example, the compound shown in formula (1') below, where X is 3. In formula (1') below, R 1 This is the same as in formula (1) above, and is, for example, a methyl group. 1When X is a methyl group, the silicon compound is tris(hydroxy)methylsilane. When X is 3, the silicon compound is, for example, a trifunctional silane having three functional groups.

[0191] [ka]

[0192] Furthermore, a specific example of a silicon compound represented by formula (1) is a compound in which X is 4. In this case, the silicon compound is, for example, a tetrafunctional silane having four functional groups.

[0193] The silicon compound may be, for example, a precursor that forms the silicon compound of formula (1) by hydrolysis. The precursor can be, for example, any substance that can produce the silicon compound by hydrolysis, and a specific example is the compound represented by formula (2).

[0194] If the silicon compound is a precursor represented by formula (2), the manufacturing method of the present invention may include, for example, a step of hydrolyzing the precursor prior to the gelation step.

[0195] The hydrolysis method is not particularly limited and can be carried out, for example, by a chemical reaction in the presence of a catalyst. Examples of the catalyst include acids such as oxalic acid and acetic acid. The hydrolysis reaction can be carried out, for example, by slowly adding an aqueous solution of oxalic acid to a dimethyl sulfoxide solution of the silicon compound precursor at room temperature, and then stirring for about 30 minutes. When hydrolyzing the silicon compound precursor, for example, by completely hydrolyzing the alkoxy group of the silicon compound precursor, subsequent gelation, maturation, heating after void structure formation, and immobilization can be achieved more efficiently.

[0196] In the present invention, the silicon compound can be exemplified by, for example, a hydrolyzed product of trimethoxy(methyl)silane.

[0197] The silicon compound monomer is not particularly limited and can be appropriately selected depending on the application of the functional porous material to be manufactured. In the manufacture of the functional porous material, the silicon compound is preferably trifunctional silane when low refractive index is important due to its excellent low refractive index, and preferably tetrafunctional silane when strength (e.g., scratch resistance) is important due to its excellent scratch resistance. Furthermore, the silicon compound used as the raw material for the silicon compound gel may be, for example, only one type or two or more types in combination. Specifically, the silicon compound may contain only trifunctional silane, only tetrafunctional silane, both trifunctional silane and tetrafunctional silane, or other silicon compounds. When two or more silicon compounds are used, their ratio is not particularly limited and can be set as appropriate.

[0198] The gelation of the porous material, such as the silicon compound, can be carried out, for example, by a dehydration condensation reaction between the porous materials. The dehydration condensation reaction is preferably carried out in the presence of a catalyst, and examples of the catalyst include acid catalysts such as hydrochloric acid, oxalic acid, and sulfuric acid, and dehydration condensation catalysts such as ammonia, potassium hydroxide, sodium hydroxide, and ammonium hydroxide. The dehydration condensation catalyst may be either an acid catalyst or a base catalyst, but a base catalyst is preferred. In the dehydration condensation reaction, the amount of catalyst added to the porous material is not particularly limited, and for example, 0.01 to 10 moles, 0.05 to 7 moles, or 0.1 to 5 moles of catalyst per mole of porous material.

[0199] The gelation of the porous material, such as the silicon compound, is preferably carried out in a solvent. The proportion of the porous material in the solvent is not particularly limited. Examples of the solvent include dimethyl sulfoxide (DMSO), N-methylpyrrolidone (NMP), N,N-dimethylacetamide (DMAc), dimethylformamide (DMF), γ-butyllactone (GBL), acetonitrile (MeCN), and ethylene glycol ethyl ether (EGEE). The solvent may be one type or two or more types may be used in combination. The solvent used for gelation will also be referred to as the "gelling solvent" below.

[0200] The conditions for gelation are not particularly limited. The treatment temperature for the solvent containing the porous body is, for example, 20-30°C, 22-28°C, or 24-26°C, and the treatment time is, for example, 1-60 minutes, 5-40 minutes, or 10-30 minutes. When the dehydration condensation reaction is carried out, the treatment conditions are not particularly limited, and these examples can be used. When the porous body is a silicon compound, by performing the gelation, for example, siloxane bonds grow, primary particles of the silicon compound are formed, and as the reaction proceeds further, the primary particles are linked together in a bead-like manner, and a three-dimensional gel structure is generated.

[0201] The gel morphology of the porous body obtained in the gelation step is not particularly limited. Generally, "gel" refers to a solidified state in which solutes have aggregated structures that have lost their independent mobility due to interactions. Among gels, a wet gel generally refers to one in which a dispersion medium is included and the solute takes on a uniform structure in the dispersion medium, while a xerogel refers to one in which the solvent is removed and the solute takes on a network structure with voids. In the present invention, it is preferable to use a wet gel for the silicon compound gel. When the porous gel is a silicon compound gel, the residual silanol groups of the silicon compound gel are not particularly limited, and for example, the range described later can be similarly exemplified.

[0202] The porous gel obtained by the gelation process may, for example, be subjected to the solvent replacement step and the first grinding step as is, but prior to the first grinding step, it may be subjected to a maturation process in the maturation step. The maturation step involves maturing the gelled porous body (porous gel) in a solvent. In the maturation step, the conditions for the maturation process are not particularly limited, and for example, the porous gel may be incubated in a solvent at a predetermined temperature. According to the maturation process, for example, the primary particles of the porous gel having a three-dimensional structure obtained by gelation can be further grown, thereby increasing the size of the particles themselves. As a result, the contact state of the neck portions where the particles are in contact can be increased from, for example, point contact to surface contact. The porous gel that has undergone such a maturation process has, for example, increased strength of the gel itself, and as a result, the strength of the three-dimensional basic structure of the pulverized material after grinding can be further improved. As a result, when a coating film is formed using the gel pulverized liquid of the present invention, for example, even during the drying process after coating, it is possible to suppress the shrinkage of the pore size of the void structure in which the three-dimensional basic structure is deposited, due to the volatilization of the solvent in the coating film that occurs during the drying process.

[0203] The temperature for the aging process has a lower limit of, for example, 30°C or higher, 35°C or higher, or 40°C or higher, and an upper limit of, for example, 80°C or lower, 75°C or lower, or 70°C or lower, with a range of, for example, 30-80°C, 35-75°C, or 40-70°C. The predetermined time is not particularly limited, with a lower limit of, for example, 5 hours or higher, 10 hours or higher, or 15 hours or higher, and an upper limit of, for example, 50 hours or lower, 40 hours or lower, or 30 hours or lower, with a range of, for example, 5-50 hours, 10-40 hours, or 15-30 hours. Regarding the optimal conditions for aging, it is preferable to set the conditions to one that, for example, increases the size of the primary particles in the porous gel and increases the contact area of ​​the neck portion, as described above. Furthermore, in the aging process, it is preferable to consider, for example, the boiling point of the solvent used when determining the temperature for the aging process. If the aging process is performed at too high a temperature, for example, the solvent may volatilize excessively, leading to a concentration of the coating solution and potentially causing problems such as the pores of the three-dimensional void structure to close. On the other hand, if the aging process is performed at too low a temperature, for example, the effects of aging may not be sufficiently obtained, leading to increased temperature variations over time in the mass production process and potentially resulting in inferior quality products.

[0204] The aging treatment can, for example, use the same solvent as the gelation step, and more specifically, it is preferable to apply it directly to the reactant after the gelation treatment (i.e., the solvent containing the porous gel). When the porous gel is the silicon compound gel, the number of moles of residual silanol groups contained in the silicon compound gel after the aging treatment following gelation is, for example, the ratio of residual silanol groups when the number of moles of alkoxy groups in the raw materials used for gelation (e.g., the silicon compound or its precursor) is set to 100, with a lower limit of, for example, 50% or more, 40% or more, or 30% or more, and an upper limit of, for example, 1% or less, 3% or less, or 5% or less, and a range of, for example, 1-50%, 3-40%, or 5-30%. For the purpose of increasing the hardness of the silicon compound gel, for example, a lower number of moles of residual silanol groups is preferable. If the number of moles of residual silanol groups is too high, for example, in the formation of the functional porous material, the void structure may not be maintained until the precursor of the functional porous material is crosslinked. On the other hand, if the number of moles of residual silanol groups is too low, for example, in the bonding step, the precursor of the functional porous material may not be able to be crosslinked, and sufficient film strength may not be imparted. The above is an example of residual silanol groups, but for example, if the silicon compound is modified with various reactive functional groups as the raw material for the silicon compound gel, the same phenomenon can be applied to each functional group.

[0205] The porous gel obtained by the gelation process is subjected to, for example, a maturation process in the maturation step, followed by a solvent replacement step, and then subjected to the gel grinding step. The solvent replacement step involves replacing the solvent with another solvent.

[0206] In the present invention, the gel grinding step is a step of grinding the porous gel as described above. The grinding may be performed, for example, on the porous gel after the gelation step, or on the porous gel after the maturation treatment.

[0207] Furthermore, as described above, a gel morphology control step may be performed prior to the solvent replacement step (for example, after the maturation step) to control the shape and size of the gel. The shape and size of the gel controlled in the gel morphology control step are not particularly limited, but are, for example, as described above. The gel morphology control step may be performed, for example, by dividing the gel into three-dimensional bodies of appropriate size and shape (for example, by cutting it).

[0208] Furthermore, as described above, the gel is subjected to the solvent replacement step before the gel grinding step. The solvent replacement step involves replacing the solvent with another solvent. If the solvent is not replaced with the other solvent, for example, the catalyst and solvent used in the gelation step may remain after the maturation step, potentially causing further gelation over time and affecting the pot life of the final gel-grinding-containing liquid, or reducing the drying efficiency when drying the coating film formed using the gel-grinding-containing liquid. The other solvent used in the gel grinding step will also be referred to below as the "grinding solvent."

[0209] The aforementioned pulverizing solvent (other solvent) is not particularly limited, and for example, organic solvents can be used. Examples of such organic solvents include solvents with boiling points of 140°C or lower, 130°C or lower, 100°C or lower, and 85°C or lower. Specific examples include isopropyl alcohol (IPA), ethanol, methanol, n-butanol, 2-butanol, isobutyl alcohol, pentyl alcohol, propylene glycol monomethyl ether (PGME), methyl cellosolve, and acetone. The aforementioned pulverizing solvent may be one type or a combination of two or more types.

[0210] Furthermore, if the polarity of the grinding solvent is low, for example, the solvent replacement process may be divided into multiple solvent replacement stages, and in the solvent replacement stages, the hydrophilicity of the other solvent may be lower in the later stages than in the earlier stages. By doing so, for example, the solvent replacement efficiency can be improved and the amount of gel manufacturing solvent (e.g., DMSO) remaining in the gel can be kept extremely low. As a specific example, the solvent replacement process may be divided into three solvent replacement stages, in the first solvent replacement stage, the DMSO in the gel may be replaced with water, then in the second solvent replacement stage, the water in the gel may be replaced with IPA, and then in the third replacement stage, the IPA in the gel may be replaced with isobutyl alcohol.

[0211] The combination of the gelling solvent and the grinding solvent is not particularly limited, and examples include combinations of DMSO and IPA, DMSO and ethanol, DMSO and isobutyl alcohol, and DMSO and n-butanol. By substituting the gelling solvent with the grinding solvent in this way, for example, a more uniform coating film can be formed in the coating film formation described later.

[0212] The solvent replacement step is not particularly limited, but can be carried out as follows: First, the gel produced by the gel production step (for example, the gel after the maturation treatment) is immersed in or in contact with the other solvent to dissolve the gel production catalyst, alcohol components produced by the condensation reaction, water, etc. in the gel into the other solvent. Then, the solvent in which the gel was immersed or in contact is discarded, and the gel is immersed in or in contact with a new solvent again. This is repeated until the amount of gel production solvent remaining in the gel reaches the desired amount. The immersion time per cycle is, for example, 0.5 hours or more, 1 hour or more, or 1.5 hours or more, and the upper limit is not particularly limited, but for example, it is 10 hours or less. The immersion in the solvent may also be carried out by continuous contact of the solvent with the gel. The temperature during immersion is not particularly limited, but may be, for example, 20-70°C, 25-65°C, or 30-60°C. Heating accelerates solvent substitution, requiring less solvent for substitution; however, solvent substitution can also be performed simply at room temperature. Furthermore, if the solvent substitution process is divided into multiple solvent substitution stages, each of these stages may be carried out in the manner described above.

[0213] If the solvent substitution process is divided into multiple solvent substitution steps, and the hydrophilicity of the other solvent is lower in later steps than in earlier steps, the other solvent (substitution solvent) is not particularly limited. In the final solvent substitution step, it is preferable that the other solvent (substitution solvent) is a solvent for producing a void layer. Examples of solvents for producing a void layer include solvents with a boiling point of 140°C or lower. Examples of solvents for producing a void layer include alcohols, ethers, ketones, ester solvents, aliphatic hydrocarbon solvents, aromatic solvents, etc. Specific examples of alcohols with a boiling point of 140°C or lower include isopropyl alcohol (IPA), ethanol, methanol, n-butanol, 2-butanol, isobutyl alcohol (IBA), 1-pentanol, 2-pentanol, etc. Specific examples of ethers with a boiling point of 140°C or lower include propylene glycol monomethyl ether (PGME), methyl cellosolve, ethyl cellosolve, etc. Specific examples of ketones with a boiling point of 140°C or less include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclopentanone. Specific examples of ester solvents with a boiling point of 140°C or less include ethyl acetate, butyl acetate, isopropyl acetate, and n-propyl acetate. Specific examples of aliphatic hydrocarbon solvents with a boiling point of 140°C or less include hexane, cyclohexane, heptane, and octane. Specific examples of aromatic solvents with a boiling point of 140°C or less include toluene, benzene, xylene, and anisole. From the viewpoint of minimizing corrosion of the substrate (e.g., resin film) during coating, the solvent for producing the void layer is preferably an alcohol, ether, or aliphatic hydrocarbon solvent. Furthermore, the pulverizing solvent may be, for example, one type or a combination of two or more types. In particular, isopropyl alcohol (IPA), ethanol, n-butanol, 2-butanol, isobutyl alcohol (IBA), pentyl alcohol, propylene glycol monomethyl ether (PGME), methyl cellosolve, heptane, and octane are preferred due to their low volatility at room temperature.In particular, in order to suppress the scattering of particles (e.g., silica compounds) that make up the gel, it is preferable that the saturated vapor pressure of the solvent for producing the void layer is not too high (it is not too volatile). As such a solvent, for example, a solvent having an aliphatic group with 3 or 4 or more carbon atoms is preferred, and a solvent having an aliphatic group with 4 or more carbon atoms is more preferred. The solvent having an aliphatic group with 3 or 4 or more carbon atoms may be, for example, an alcohol. Specifically, as such a solvent, for example, isopropyl alcohol (IPA), isobutyl alcohol (IBA), n-butanol, 2-butanol, 1-pentanol, and 2-pentanol are preferred, and isobutyl alcohol (IBA) is particularly preferred.

[0214] The other solvent (substitution solvent) used in steps other than the final solvent substitution step is not particularly limited, but examples include alcohols, ethers, and ketones. Specific examples of alcohols include isopropyl alcohol (IPA), ethanol, methanol, n-butanol, 2-butanol, isobutyl alcohol (IBA), and pentyl alcohol. Specific examples of ethers include propylene glycol monomethyl ether (PGME), methyl cellosolve, and ethyl cellosolve. Specific examples of ketones include acetone. The other solvent (substitution solvent) only needs to be capable of substituting the gel manufacturing solvent or the other solvent (substitution solvent) used in the preceding steps. Furthermore, it is preferable that the other solvent (substitution solvent) used in steps other than the final solvent substitution step does not ultimately remain in the gel, or, if it does remain, does not easily corrode the substrate (e.g., resin film) during coating. From the viewpoint of minimizing corrosion of the substrate (e.g., resin film) during coating, the other solvent (substitution solvent) in steps other than the final solvent substitution step is preferably an alcohol. Thus, it is preferable that the other solvent is an alcohol in at least one of the plurality of solvent substitution steps.

[0215] In the solvent replacement step performed first, the other solvent may be, for example, water or a mixed solvent containing water in any proportion. If it is water or a mixed solvent containing water, it has high compatibility with the solvent for producing a gel with high hydrophilicity (for example, DMSO), so it is easy to replace the solvent for producing the gel, and it is also preferable in terms of cost.

[0216] The plurality of solvent replacement steps may include a step in which the other solvent is water, a step performed thereafter in which the other solvent is a solvent having an aliphatic group with 3 or less carbon atoms, and a step performed further thereafter in which the other solvent is a solvent having an aliphatic group with 4 or more carbon atoms. Further, at least one of the solvent having an aliphatic group with 3 or less carbon atoms and the solvent having an aliphatic group with 4 or more carbon atoms may be alcohol. The alcohol having an aliphatic group with 3 or less carbon atoms is not particularly limited, and examples thereof include isopropyl alcohol (IPA), ethanol, methanol, n-propyl alcohol, and the like. The alcohol having an aliphatic group with 4 or more carbon atoms is not particularly limited, and examples thereof include n-butanol, 2-butanol, isobutyl alcohol (IBA), pentyl alcohol, and the like. For example, the solvent having an aliphatic group with 3 or less carbon atoms may be isopropyl alcohol, and the solvent having an aliphatic group with 4 or more carbon atoms may be isobutyl alcohol.

[0217] The inventors of the present invention have found that, for example, in order to form a void layer with film strength under relatively mild conditions of 200 ° C or lower, it is very important to pay attention to the remaining amount of the solvent for producing the gel. This finding is not shown in the prior art including the above-mentioned patent documents and non-patent documents, and is a finding independently found by the inventors of the present invention.

[0218] Thus, although the reason (mechanism) for being able to manufacture a low refractive index void layer by reducing the residual amount of the solvent for gel production in the gel is unknown, it is presumed as follows, for example. That is, as described above, for the solvent for gel production, a high boiling point solvent (for example, DMSO or the like) is preferable for the progress of the gelation reaction. And when producing a void layer by coating and drying the sol solution produced from the gel, it is difficult to completely remove the high boiling point solvent at normal drying temperatures and drying times (although not particularly limited, for example, 1 minute at 100 ° C, etc.). This is because if the drying temperature is too high or the drying time is too long, problems such as deterioration of the substrate may occur. And it is presumed that the high boiling point solvent remaining during the coating and drying gets between the pulverized materials of the gel, makes the pulverized materials slide, and the pulverized materials densely accumulate, resulting in a decrease in the porosity and making it difficult to exhibit a low refractive index. That is, conversely, if the residual amount of the high boiling point solvent is reduced, such a phenomenon can be suppressed and it is considered that a low refractive index can be exhibited. However, these are examples of the presumed mechanism and do not limit the present invention in any way.

[0219] In the present invention, the "solvent" (for example, the solvent for gel production, the solvent for void layer production, the substitution solvent, etc.) does not necessarily have to dissolve the gel or its pulverized material, etc. For example, the gel or its pulverized material, etc. may be dispersed or precipitated in the solvent.

[0220] As described above, the solvent for gel production may have a boiling point of 140 ° C or higher, for example.

[0221] The solvent for gel production is, for example, a water-soluble solvent. In the present invention, the "water-soluble solvent" refers to a solvent that can be mixed with water in any ratio.

[0222] When the solvent replacement process is divided into multiple solvent replacement steps, the method is not particularly limited, but each solvent replacement step can be carried out, for example, as follows: First, the gel is immersed in or in contact with the other solvent to dissolve the gel manufacturing catalyst, alcohol components produced by the condensation reaction, water, etc. in the gel into the other solvent. Then, the solvent in which the gel was immersed or in contact is discarded, and the gel is immersed in or in contact with a new solvent again. This is repeated until the amount of gel manufacturing solvent remaining in the gel reaches the desired amount. The immersion time per cycle is, for example, 0.5 hours or more, 1 hour or more, or 1.5 hours or more, and the upper limit is not particularly limited, but for example, it is 10 hours or less. The immersion in the solvent may also be carried out by continuous contact of the solvent with the gel. The temperature during immersion is not particularly limited, but for example, it may be 20-70°C, 25-65°C, or 30-60°C. Heating accelerates solvent substitution, requiring less solvent for the substitution; however, solvent substitution can also be performed simply at room temperature. In this solvent substitution stage, the other solvent (substitution solvent) is gradually changed from a highly hydrophilic solvent to a less hydrophilic (highly hydrophobic) solvent, and this process is repeated multiple times. To remove highly hydrophilic gel manufacturing solvents (e.g., DMSO), for example, as mentioned above, using water as the substitution solvent first is simple and efficient. After removing DMSO with water, the water in the gel is replaced, for example, with isopropyl alcohol followed by isobutyl alcohol (coating solvent). That is, because water and isobutyl alcohol have low compatibility, solvent substitution can be performed efficiently by first substituting with isopropyl alcohol and then with isobutyl alcohol, which is a coating solvent. However, this is just one example, and as mentioned above, the other solvent (substitution solvent) is not particularly limited.

[0223] In the present invention, the method for producing the gel may, for example, be carried out multiple times in the solvent substitution step, gradually changing the other solvent (substitution solvent) from a highly hydrophilic solvent to a less hydrophilic (highly hydrophobic) solvent, as described above. As a result, as described above, the amount of gel-producing solvent remaining in the gel can be kept extremely low. Moreover, it is possible to reduce the amount of solvent used and lower costs compared to, for example, performing solvent substitution in one step using only a coating solvent.

[0224] Then, after the solvent replacement step, a gel grinding step is performed in which the gel is ground in the grinding solvent. Alternatively, as described above, after the solvent replacement step and prior to the gel grinding step, the gel concentration may be measured as needed, and thereafter, the gel concentration adjustment step may be performed as needed. The gel concentration measurement after the solvent replacement step and prior to the gel grinding step can be performed, for example, as follows. First, after the solvent replacement step, the gel is removed from the other solvent (grinding solvent). This gel is controlled to a suitable shape and size (for example, block-shaped) by the gel morphology control step, for example. Next, after removing the solvent adhering to the gel mass, the solid content concentration in one gel mass is measured by weight drying. At this time, in order to ensure the reproducibility of the measurement values, the measurement is performed on multiple (for example, six) randomly selected masses, and the average value and the variation of the values ​​are calculated. The concentration adjustment step may, for example, decrease the gel concentration of the gel-containing liquid by adding another solvent (grinding solvent). Alternatively, the concentration adjustment step may increase the gel concentration of the gel-containing liquid by evaporating the other solvent (grinding solvent).

[0225] In the method for producing a gel-pulverized liquid of the present invention, as described above, the gel pulverization step may be performed in one step, but it is preferable to divide it into multiple pulverization steps. Specifically, for example, the first pulverization step and the second pulverization step may be performed. Furthermore, in addition to the first pulverization step and the second pulverization step, a further gel pulverization step may be performed. In other words, in the production method of the present invention, the gel pulverization step is not limited to only two pulverization steps, but may include three or more pulverization steps.

[0226] As described above, a liquid (e.g., suspension) containing the microporous particles (pulverized gel-like compound) can be prepared. Furthermore, a liquid containing the microporous particles and the catalyst can be prepared by adding a catalyst that chemically bonds the microporous particles together after preparing the liquid containing the microporous particles, or during the preparation process. The amount of catalyst added is not particularly limited, but is, for example, 0.01 to 20% by weight, 0.05 to 10% by weight, or 0.1 to 5% by weight relative to the weight of the pulverized gel-like silicon compound. The catalyst may be, for example, a catalyst that promotes cross-linking of the microporous particles. It is preferable to utilize the dehydration condensation reaction of residual silanol groups contained in silica sol molecules as the chemical reaction that chemically bonds the microporous particles together. By promoting the reaction between the hydroxyl groups of the silanol groups with the catalyst, continuous film formation that hardens the void structure in a short time is possible. Examples of the catalyst include photoactive catalysts and thermally activated catalysts. According to the photoactive catalyst, for example, in the void layer formation step, the microporous particles can be chemically bonded together (e.g., cross-linked) without heating. As a result, for example, in the void layer formation step, shrinkage of the entire void layer is less likely to occur, and a higher porosity can be maintained. In addition to or in place of the catalyst, a substance that generates a catalyst (catalyst generator) may be used. For example, in addition to or in place of the photoactive catalyst, a substance that generates a catalyst by light (photocatalyst generator) may be used, or in addition to or in place of the thermally activated catalyst, a substance that generates a catalyst by heat (thermal catalyst generator) may be used. The photocatalyst generator is not particularly limited, but examples include a photobase generator (a substance that generates a basic catalyst by light irradiation), a photoacid generator (a substance that generates an acidic catalyst by light irradiation), etc., and a photobase generator is preferred.Examples of the aforementioned photobase generators include 9-anthrylmethyl N,N-diethylcarbamate (trade name WPBG-018), (E)-1-[3-(2-hydroxyphenyl)-2-propenoyl]piperidine (trade name WPBG-027), 1-(anthraquinon-2-yl)ethyl imidazolecarboxylate (trade name WPBG-140), 2-nitrophenylmethyl 4-methacryloyloxypiperidine-1-carboxylate (trade name WPBG-165), and 1,2-diisopropyl-3-[bis(dimethylamino)methylene]guanidium Examples include 2-(3-benzoylphenyl)propionate (trade name WPBG-266), 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidium n-butyltriphenyl borate (trade name WPBG-300), and 1,5,7-triazabicyclo[4.4.0]deca-5-ene 2-(9-oxoxanthene-2-yl)propionic acid (Tokyo Chemical Industries, Ltd.), and compounds containing 4-piperidine methanol (trade name HDPD-PB100: manufactured by Heraeus). Note that all trade names containing "WPBG" are trade names of Wako Pure Chemical Industries, Ltd. Examples of photoacid generators include aromatic sulfonium salts (trade name SP-170: ADEKA), triarylsulfonium salts (trade name CPI101A: Sunapro), and aromatic iodonium salts (trade name Irgacure250: Ciba Japan). Furthermore, the catalyst for chemically bonding the microporous particles is not limited to the photoactive catalyst and the photocatalyst generator, but may also be a thermally activated catalyst or a thermal catalyst generator, for example. Examples of catalysts for chemically bonding the microporous particles include base catalysts such as potassium hydroxide, sodium hydroxide, and ammonium hydroxide, and acid catalysts such as hydrochloric acid, acetic acid, and oxalic acid. Among these, base catalysts are preferred.The catalyst or catalyst generator that chemically bonds the microporous particles together can be used, for example, by adding it to a sol particle liquid (e.g., suspension) containing the pulverized material (microporous particles) immediately before coating, or by using it as a mixture of the catalyst or catalyst generator in a solvent. The mixture may be, for example, a coating solution obtained by directly adding and dissolving it in the sol particle liquid, a solution in which the catalyst or catalyst generator is dissolved in a solvent, or a dispersion in which the catalyst or catalyst generator is dispersed in a solvent. The solvent is not particularly limited and can be, for example, water, a buffer solution, etc.

[0227] Furthermore, for example, by adding a small amount of a high-boiling-point solvent to the liquid containing the microporous particles after preparing the liquid, it is possible to improve the appearance of the film during film formation by coating. The amount of the high-boiling-point solvent is not particularly limited, but is, for example, 0.05 to 0.8 times, 0.1 to 0.5 times, and particularly 0.15 to 0.4 times the amount of solid content of the liquid containing the microporous particles. The high-boiling-point solvent is not particularly limited, but examples include dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), γ-butyllactone (GBL), and ethylene glycol ethyl ether (EGEE). Solvents with a boiling point of 110°C or higher are particularly preferred, and are not limited to the above specific examples. The high-boiling-point solvent is thought to act as a leveling agent during film formation when particles are arranged in a line. It is also preferable to use the high-boiling-point solvent during gel synthesis. However, although the details are unclear, it appears that the high-boiling point solvent works more efficiently when the solvent used during synthesis is completely removed, and then the liquid containing the microporous particles is prepared and the high-boiling point solvent is added again. However, these mechanisms are illustrative and do not limit the present invention in any way.

[0228] Then, nanoparticles surface-modified with the surface-oriented compound are added to the manufactured gel pulverized liquid, and this can be used to manufacture the void layer of the present invention. In this case, for example, as described above, the nanoparticles may be added in a proportion such that they amount to, for example, 10-50% by mass, 15-40% by mass, or 20-30% by mass relative to the skeletal component of the void layer.

[0229] [5-3. Method for manufacturing void layers, laminates, and adhesive layers] The method for manufacturing the laminate of the present invention will be described below with examples, together with the method for manufacturing the void layer and adhesive layer of the present invention that constitute the laminate. In the following, the case in which the void layer of the present invention is a silicone porous material formed from a silicon compound will be mainly described. However, the void layer of the present invention is not limited to a silicone porous material. In cases where the void layer of the present invention is a material other than a silicone porous material, the following description may be applied mutatis mutandis unless otherwise specified. Furthermore, in the following, the gel pulverized material-containing liquid used in the manufacture of the void layer of the present invention shall contain nanoparticles surface-modified with the surface-oriented compound unless otherwise specified. The nanoparticles surface-modified with the surface-oriented compound can be added to the gel pulverized material-containing liquid after its manufacture, for example, as described above.

[0230] The method for producing a void layer according to the present invention includes, for example, a precursor formation step of forming a precursor of the void layer using the gel pulverized material-containing liquid of the present invention, and a bonding step of chemically bonding the pulverized materials in the gel pulverized material-containing liquid contained in the precursor. The precursor may also be, for example, a coating film.

[0231] According to the method for manufacturing a void layer of the present invention, a porous structure that performs a function similar to that of an air layer is formed. The reason for this is presumed to be, for example, as follows, but the present invention is not limited to this presumption. The following explanation will be given using the case in which the void layer of the present invention is a porous silicone material as an example.

[0232] The gel pulverized material-containing liquid of the present invention used in the method for manufacturing the silicone porous material contains pulverized silicon compound gel, so that the three-dimensional structure of the gel-like silica compound is dispersed in a three-dimensional basic structure. For this reason, in the method for manufacturing the silicone porous material, for example, when the precursor (e.g., a coating film) is formed using the gel pulverized material-containing liquid, the three-dimensional basic structure is deposited, and a void structure based on the three-dimensional basic structure is formed. In other words, according to the method for manufacturing the silicone porous material, a new three-dimensional structure is formed from the pulverized material of the three-dimensional basic structure, which is different from the three-dimensional structure of the silicon compound gel. Furthermore, in the method for manufacturing the silicone porous material, the pulverized material is chemically bonded together, thereby immobilizing the new three-dimensional structure. For this reason, the silicone porous material obtained by the method for manufacturing the silicone porous material has a void structure, but can maintain sufficient strength and flexibility. The void layer obtained by the present invention (for example, a porous silicone material) can be used in a wide range of products, such as thermal insulation materials, sound-absorbing materials, optical components, and ink-receiving layers, as a component that utilizes the voids. Furthermore, laminated films with various functions can be manufactured using this method.

[0233] Unless otherwise specified, the method for producing the void layer of the present invention can be described by referring to the description of the gel-containing liquid of the present invention.

[0234] In the process of forming the precursor of the porous body, for example, the gel pulverized material-containing liquid of the present invention is coated onto the substrate. The gel pulverized material-containing liquid of the present invention can be coated onto the substrate, for example, and after the coating film is dried, the pulverized material is chemically bonded to itself (for example, crosslinked) in the bonding step, thereby enabling the continuous formation of a void layer having a film strength of a certain level or higher.

[0235] The amount of the gel pulverized material-containing liquid applied to the substrate is not particularly limited and can be appropriately set according to, for example, the desired thickness of the void layer of the present invention. As a specific example, when forming the silicone porous body with a thickness of 0.1 to 1000 μm, the amount of the gel pulverized material-containing liquid applied to the substrate is the amount applied to the area of ​​the substrate per 1 m².2 For example, the amount of the pulverized material is 0.01 to 60,000 μg, 0.1 to 5,000 μg, or 1 to 50 μg. The preferred coating amount of the gel pulverized material-containing liquid is difficult to define uniquely, as it is related to factors such as the liquid concentration and coating method. However, considering productivity, it is preferable to coat the material in the thinnest possible layer. If the coating amount is too large, for example, there is a higher possibility that the material will be dried in a drying oven before the solvent evaporates. This can lead to the formation of voids being inhibited and the porosity being greatly reduced, as the solvent dries before the nano-pulverized sol particles can settle and accumulate in the solvent and form a void structure. On the other hand, if the coating amount is too thin, there is a higher risk of coating defects occurring due to variations in the surface texture and hydrophilicity of the substrate.

[0236] After coating the substrate with the gel pulverized material-containing liquid, the porous precursor (coated film) may be subjected to a drying treatment. The purpose of this drying treatment is not only to remove the solvent (the solvent contained in the gel pulverized material-containing liquid) from the porous precursor, but also to allow sol particles to settle and accumulate during the drying treatment, thereby forming a void structure. The drying temperature is, for example, 50-250°C, 60-150°C, or 70-130°C, and the drying time is, for example, 0.1-30 minutes, 0.2-10 minutes, or 0.3-3 minutes. Regarding the drying temperature and time, for example, lower and shorter temperatures are preferable in relation to continuous productivity and the development of a high porosity. If the conditions are too severe, for example, if the substrate is a resin film, the substrate may expand in the drying oven as it approaches its glass transition temperature, and defects such as cracks may occur in the formed void structure immediately after coating. On the other hand, if the conditions are too lenient, for example, residual solvent may be present when the product leaves the drying oven, potentially causing cosmetic defects such as scratches when it rubs against the rolls in the next process.

[0237] The drying treatment may be, for example, natural drying, heat drying, or vacuum drying. The drying method is not particularly limited, and for example, general heating means can be used. Examples of the heating means include a hot air blower, a heating roll, a far-infrared heater, etc. Among these, when assuming industrial continuous production, it is preferable to use heat drying. Also, for the solvent to be used, a solvent with a low surface tension is preferable for the purpose of suppressing the generation of shrinkage stress associated with solvent volatilization during drying and the resulting crack phenomenon in the void layer (the silicone porous body). Examples of the solvent include, but are not limited to, lower alcohols typified by isopropyl alcohol (IPA), hexane, perfluorohexane, etc.

[0238] The base material is not particularly limited. For example, a base material made of a thermoplastic resin, a glass base material, an inorganic substrate typified by silicon, a plastic formed from a thermosetting resin, an element such as a semiconductor, a carbon fiber-based material typified by carbon nanotubes, etc. can be preferably used, but not limited thereto. Examples of the form of the base material include a film, a plate, etc. Examples of the thermoplastic resin include polyethylene terephthalate (PET), acrylic, cellulose acetate propionate (CAP), cycloolefin polymer (COP), triacetyl cellulose (TAC), polyethylene naphthalate (PEN), polyethylene (PE), polypropylene (PP), etc.

[0239] In the method for manufacturing a void layer of the present invention, the bonding step is a step of chemically bonding the pulverized material contained in the porous precursor (coating film). Through this bonding step, for example, the three-dimensional structure of the pulverized material in the porous precursor is immobilized. In conventional immobilization by sintering, for example, high-temperature treatment of 200°C or higher induces dehydration condensation of silanol groups and the formation of siloxane bonds. In the bonding step of the present invention, by reacting various additives that catalyze the above-mentioned dehydration condensation reaction, for example, when the substrate is a resin film, the void structure can be continuously formed and immobilized at a relatively low drying temperature of around 100°C and a short processing time of less than a few minutes without damaging the substrate.

[0240] The method of chemical bonding is not particularly limited and can be appropriately determined depending on the type of gel (e.g., silicon compound gel). Specifically, the chemical bonding can be achieved, for example, by chemical crosslinking between the pulverized materials. Alternatively, if inorganic particles such as titanium dioxide are added to the pulverized material, chemical crosslinking between the inorganic particles and the pulverized material is also conceivable. Furthermore, when supporting biocatalysts such as enzymes, chemical crosslinking may be performed between the pulverized material and a site other than the catalytic active site. Therefore, the present invention can be applied not only to void layers formed between sol particles, but also to organic-inorganic hybrid void layers, host-guest void layers, etc., but is not limited to these.

[0241] The bonding step can be carried out by a chemical reaction in the presence of a catalyst, depending on the type of pulverized gel (e.g., silicon compound gel). In the present invention, it is preferable to utilize the dehydration condensation reaction of residual silanol groups contained in the pulverized silicon compound gel as the chemical reaction. By promoting the reaction between hydroxyl groups of silanol groups with the catalyst, continuous film formation with a void structure hardened in a short time is possible. Examples of the catalyst include, but are not limited to, base catalysts such as potassium hydroxide, sodium hydroxide, and ammonium hydroxide, and acid catalysts such as hydrochloric acid, acetic acid, and oxalic acid. A base catalyst is particularly preferred as the catalyst for the dehydration condensation reaction. Photoacid generation catalysts and photobase generation catalysts, which exhibit catalytic activity when irradiated with light (e.g., ultraviolet light), can also be preferably used. The photoacid generation catalyst and photobase generation catalyst are not particularly limited, but are examples as described above. The catalyst is preferably used by adding it to the sol particle liquid containing the pulverized material immediately before coating, as described above, or by using a mixed solution in which the catalyst is mixed with a solvent. The aforementioned mixture may be, for example, a coating solution obtained by directly adding and dissolving the sol particle solution, a solution obtained by dissolving the catalyst in a solvent, or a dispersion obtained by dispersing the catalyst in a solvent. The solvent is not particularly limited and, as mentioned above, examples include water, buffer solution, etc.

[0242] Furthermore, for example, the gel-containing liquid of the present invention may also contain a crosslinking aid for indirectly bonding the pulverized gel particles together. This crosslinking aid penetrates between the particles (the pulverized particles), and the particles and the crosslinking aid interact or bond with each other, making it possible to bond particles that are somewhat far apart, thereby efficiently increasing strength. A highly crosslinked silane monomer is preferred as the crosslinking aid. Specifically, the highly crosslinked silane monomer may have, for example, two to three alkoxysilyl groups, and the chain length between the alkoxysilyl groups may be between one and ten carbon atoms, and may also contain elements other than carbon. Examples of the aforementioned crosslinking aids include bis(trimethoxysilyl)ethane, bis(triethoxysilyl)ethane, bis(trimethoxysilyl)methane, bis(triethoxysilyl)methane, bis(triethoxysilyl)propane, bis(trimethoxysilyl)propane, bis(triethoxysilyl)butane, bis(trimethoxysilyl)butane, bis(triethoxysilyl)pentane, bis(trimethoxysilyl)pentane, bis(triethoxysilyl)hexane, bis(trimethoxysilyl)hexane, bis(trimethoxysilyl)-N-butyl-N-propyl-ethane-1,2-diamine, tris-(3-trimethoxysilylpropyl)isocyanurate, and tris-(3-triethoxysilylpropyl)isocyanurate. The amount of this crosslinking aid added is not particularly limited, but for example, it is 0.01 to 20% by weight, 0.05 to 15% by weight, or 0.1 to 10% by weight relative to the weight of the pulverized silicon compound.

[0243] The chemical reaction in the presence of the catalyst can be carried out, for example, by irradiating or heating the coating film containing the catalyst or catalyst generator that has been previously added to the gel pulverized liquid, or by spraying the catalyst onto the coating film and then irradiating or heating it, or by irradiating or heating it while spraying the catalyst or catalyst generator. For example, if the catalyst is a photoactive catalyst, the porous silicone material can be formed by chemically bonding the microporous particles together through light irradiation. If the catalyst is a thermally activated catalyst, the porous silicone material can be formed by chemically bonding the microporous particles together through heating. The amount of light irradiation (energy) in the light irradiation is not particularly limited, but for example, 200 to 800 mJ / cm² at 360 nm. 2 250-600 mJ / cm² 2 , or 300-400 mJ / cm² 2 Therefore, to prevent insufficient irradiation and subsequent decomposition of the catalyst generator by light absorption, the recommended irradiation dose is 200 mJ / cm². 2 The above cumulative light intensity is good. Also, from the perspective of preventing damage to the substrate below the void layer and the occurrence of thermal wrinkles, 800 mJ / cm is appropriate. 2 The following integrated light intensity is preferable. The wavelength of light in the light irradiation is not particularly limited, but for example, it is 200-500 nm or 300-450 nm. The light irradiation time in the light irradiation is not particularly limited, but for example, it is 0.1-30 minutes, 0.2-10 minutes, or 0.3-3 minutes. The conditions for the heat treatment are not particularly limited, and the heating temperature is for example, 50-250°C, 60-150°C, or 70-130°C, and the heating time is for example, 0.1-30 minutes, 0.2-10 minutes, or 0.3-3 minutes. Furthermore, regarding the solvent used, for example, a solvent with low surface tension is preferred in order to suppress the generation of shrinkage stress due to solvent volatilization during drying and the resulting cracking phenomenon in the void layer. Examples include, but are not limited to, lower alcohols such as isopropyl alcohol (IPA), hexane, and perfluorohexane.

[0244] As described above, the void layer of the present invention (for example, a silicone porous body) can be manufactured. However, the method for manufacturing the void layer of the present invention is not limited to the above. In the following, the void layer of the present invention, which is a silicone porous body, may be referred to as "the silicone porous body of the present invention."

[0245] The method for manufacturing a laminate of the present invention includes, for example, a method for manufacturing an adhesive layer of the present invention, which involves manufacturing the adhesive layer by the method for manufacturing the adhesive layer of the present invention, and a bonding step of bonding the adhesive layer to the void layer. The method for manufacturing the adhesive layer of the present invention includes, for example, as described above, a method for applying the adhesive coating liquid of the present invention to a substrate, and a heating and drying step of heating and drying the substrate to which the adhesive coating liquid has been applied. For example, the adhesive layer of the present invention may be formed on the void layer of the present invention by bonding the adhesive layer side of an adhesive tape or the like, on which the adhesive layer of the present invention is laminated on a substrate, onto the void layer of the present invention. In this case, the substrate, such as the adhesive tape, may be left bonded as is, or it may be peeled off from the adhesive layer. In particular, as described above, by peeling off the substrate and obtaining a void layer-containing adhesive sheet without a substrate (substrate-less), the thickness can be significantly reduced, and the increase in thickness of devices, etc., can be suppressed. In the present invention, "adhesive" and "adhesive layer" refer to, for example, an agent or layer intended for re-peeling of the adherend. In the present invention, "adhesive" and "adhesive layer" refer to, for example, an agent or layer that does not assume the re-peeling of the adherend. However, in the present invention, "tack" and "adhesive" are not necessarily clearly distinguishable, and "tack layer" and "adhesive layer" are not necessarily clearly distinguishable. In the present invention, the adhesive layer of the present invention can be manufactured using the adhesive coating liquid of the present invention as described above. The adhesive coating liquid of the present invention can be manufactured by a method for manufacturing the adhesive coating liquid of the present invention, which includes a mixing step of mixing a (meth)acrylic polymer, a monomer having one or two reactive double bonds in one molecule, an isocyanate crosslinking agent, and an organic peroxide as described above.

[0246] The adhesive layer manufacturing process can be carried out, for example, as follows. First, as described above, the adhesive coating liquid of the present invention is manufactured by a mixing step of mixing a (meth)acrylic polymer, a monomer having one or two reactive double bonds in one molecule, an isocyanate crosslinking agent, and an organic peroxide. At this time, if the adhesive coating liquid of the present invention contains other components other than the (meth)acrylic polymer, the monomer having one or two reactive double bonds in one molecule, the isocyanate crosslinking agent, and the organic peroxide, these other components may also be mixed together. For example, the polymerization solvent used during the production of the (meth)acrylic polymer may be mixed as is as a component of the adhesive coating liquid of the present invention without removal. Furthermore, the method for manufacturing the adhesive coating liquid of the present invention may include other steps other than the mixing step, but may not include them, and may simply involve mixing all the components of the adhesive coating liquid of the present invention by the mixing step.

[0247] Next, the adhesive coating liquid of the present invention is applied to the substrate (adhesive coating liquid application step). The substrate is not particularly limited and may be, for example, a film. The substrate can preferably be, but is not limited to, a thermoplastic resin substrate, a glass substrate, an inorganic substrate represented by silicon, a plastic molded from a thermosetting resin, a semiconductor or other element, or a carbon fiber material represented by carbon nanotubes. The form of the substrate can be, for example, a film or a plate. Examples of thermoplastic resins include polyethylene terephthalate (PET), acrylic, cellulose acetate propionate (CAP), cycloolefin polymer (COP), triacetylcellulose (TAC), polyethylene naphthalate (PEN), polyethylene (PE), and polypropylene (PP). Furthermore, in the adhesive coating liquid application step, the coating thickness of the adhesive coating liquid is not particularly limited, but can be appropriately adjusted, for example, so that the thickness of the adhesive layer after drying is a predetermined thickness. The thickness of the adhesive layer after drying is also not particularly limited, but can be, for example, as described below.

[0248] Next, the substrate to which the adhesive coating liquid has been applied is heated and dried (heat drying step). In this heat drying step, the heating temperature is not particularly limited, but may be, for example, 50°C or higher, 80°C or higher, 100°C or higher, or 155°C or higher, or for example, 200°C or lower, 180°C or lower, or 160°C or lower. The heating time is not particularly limited, but may be, for example, 1 minute or more, 2 minutes or more, or 3 minutes or more, or for example, 60 minutes or less, 30 minutes or less, 20 minutes or less, or 10 minutes or less. In this heat drying step, for example, a crosslinking reaction and graft polymerization occur between the (meth)acrylic polymer, the monomer having one or two reactive double bonds in one molecule, and the isocyanate crosslinking agent. As a result, for example, as described above, the amount of semi-molecular-weight polymer present in the adhesive coating liquid decreases, and the adhesive layer of the present invention becomes less likely to penetrate into the voids of the void layer. In this way, the adhesive layer of the present invention can be manufactured.

[0249] Next, the adhesive layer is bonded to the void layer (bonding step). This method is not particularly limited, but for example, as described above, the adhesive layer side of an adhesive tape or the like, in which the adhesive layer of the present invention is laminated on a substrate, may be bonded to the void layer of the present invention, thereby forming the adhesive layer on the void layer of the present invention. In this way, the laminate of the present invention can be manufactured.

[0250] In the method for manufacturing the laminate of the present invention, for example, a heating step may be performed after the bonding step in which the adhesive layer and the void layer are heated. Hereinafter, this heating step may be referred to as the "aging step". In the heating step (aging step), the heating temperature is not particularly limited, but may be, for example, 40°C or higher, 45°C or higher, or 50°C or higher, or for example, 80°C or lower, 70°C or lower, 60°C or lower, or 55°C or lower. The heating time is not particularly limited, but may be, for example, 1 minute or more, 10 minutes or more, 60 minutes or more, or 1800 minutes or more, or for example, 3000 minutes or less, 2800 minutes or less, 2500 minutes or less, or 2000 minutes or less. In this aging step, for example, the intermediate layer is formed by the coalescence of the void layer and the adhesive layer. As described above, for example, the intermediate layer acts as a stopper, suppressing the reduction in porosity due to the voids in the void layer being filled with adhesive.

[0251] The adhesive layer can protect the void layer from physical damage (especially scratches). Furthermore, the adhesive layer is preferably made of a material with excellent pressure resistance so that the void layer does not collapse, even when used as a substrate-less adhesive sheet containing the void layer, but it is not particularly limited. The thickness of the adhesive layer is also not particularly limited, but for example, it can be 0.1 to 100 μm, 5 to 50 μm, 10 to 30 μm, or 12 to 25 μm.

[0252] The void layer of the present invention obtained in this manner may be further laminated with other films (layers) to form a laminated structure including the porous structure. In this case, each component of the laminated structure may be laminated via, for example, the adhesive layer (tack or adhesive).

[0253] The lamination of the aforementioned components may be carried out by, for example, a continuous process using a long film (so-called Roll to Roll, etc.) for efficiency, or, if the substrate is a molded product or element, it may be laminated after batch processing.

[0254] The following describes a method for forming the laminate of the present invention on a substrate (resin film), with an example using Figures 1 to 3, focusing on the continuous processing steps. Figure 2 shows the process of forming the void layer (silicone porous body), then laminating a protective film and winding it up. However, when laminating onto a different functional film, the above method may be used, or the void layer formed on the other functional film may be laminated immediately before winding after coating and drying the other functional film. Note that the illustrated film formation methods are merely examples and are not limited to these.

[0255] The substrate may be the resin film described above. In this case, the void layer of the present invention can be obtained by forming the void layer on the substrate. Alternatively, the void layer of the present invention can also be obtained by forming the void layer on the substrate and then laminating the void layer onto the resin film described above in the explanation of the void layer of the present invention.

[0256] Figure 1 schematically shows an example of the steps in the manufacturing method of the laminate of the present invention, in which the void layer, the intermediate layer, and the adhesive layer are laminated on the substrate (resin film) in the order described above. In Figure 1, the method for forming the void layer includes a coating step (1) in which a sol particle liquid 20'' of the pulverized gel-like compound is applied to the substrate (resin film) 10 to form a coating film, a drying step (2) in which the sol particle liquid 20'' is dried to form a dried coating film 20', a chemical treatment step (e.g., a crosslinking step) (3) in which the coating film 20' is chemically treated (e.g., a crosslinking step) to form a void layer 20, a bonding step (4) in which an adhesive layer 30 is bonded onto the void layer 20, and an intermediate layer formation step (5) in which the void layer 20 is reacted with the adhesive layer 30 to form an intermediate layer 22. Although not shown in the figures, the method for manufacturing the laminate of the present invention also includes, as described above, a method for manufacturing the adhesive layer by the method for manufacturing the adhesive layer of the present invention, and a bonding step for bonding the adhesive layer to the void layer. The method for manufacturing the adhesive layer of the present invention also includes, as described above, a method for applying the adhesive coating liquid of the present invention to a substrate, and a heating and drying step for heating and drying the substrate to which the adhesive coating liquid has been applied. The chemical treatment step (crosslinking step) (3) corresponds to the "void layer formation step" that forms the void layer in the laminate of the present invention. The intermediate layer formation step (5) corresponds to the heating step (aging step) described above. In the figure, the intermediate layer formation step (5) (hereinafter sometimes referred to as the "aging step") also serves as a step to improve the strength of the void layer 20 (a crosslinking reaction step that causes a crosslinking reaction inside the void layer 20), and after the intermediate layer formation step (5), the void layer 20 changes into a void layer 21 with improved strength. However, the present invention is not limited thereto, and for example, the void layer 20 does not need to change after the intermediate layer formation step (5). Also, as described above, the bonding step (4) may be the bonding of an adhesive tape having an adhesive layer on a substrate. In Figure 1, the substrate to which the adhesive coating liquid has been applied (to which the adhesive layer has been formed) is not shown, but for example, it may be peeled off and removed from the adhesive layer 30, or it may be left on the adhesive layer 30.By following the above steps (1) to (5), a laminated film can be manufactured in which a void layer 21, an intermediate layer 22, and an adhesive layer 30 are laminated on a resin film 10 in the order described above, as shown in the figure. However, the intermediate layer formation step (5) may be omitted, and the laminate of the present invention manufactured may not contain an intermediate layer. Furthermore, the method for manufacturing the laminate of the present invention may include, or may not include, steps other than those described in Figure 1, as appropriate.

[0257] In the coating step (1) described above, the coating method of the sol particle liquid 20'' is not particularly limited, and a general coating method can be used. Examples of such coating methods include the slot die method, reverse gravure coating method, microgravure method (microgravure coating method), dip method (dip coating method), spin coating method, brush coating method, roll coating method, flexographic printing method, wire bar coating method, spray coating method, extrusion coating method, curtain coating method, reverse coating method, etc. Among these, the extrusion coating method, curtain coating method, roll coating method, microgravure coating method, etc. are preferred from the viewpoint of productivity and smoothness of the coating film. The amount of sol particle liquid 20'' to be coated is not particularly limited, and can be set as appropriate, for example, so that the thickness of the void layer 20 is appropriate. The thickness of the void layer 21 is not particularly limited, for example, as described above.

[0258] In the drying step (2) described above, the sol particle liquid 20'' is dried (i.e., the dispersion medium contained in the sol particle liquid 20'' is removed) to form the dried coating film (precursor of the void layer) 20''. The conditions for the drying treatment are not particularly limited and are as described above.

[0259] Furthermore, in the chemical treatment step (3), the coating film 20' containing the catalyst or catalyst generator (e.g., photoactive catalyst, photocatalyst generator, thermally activated catalyst, or thermal catalyst generator) added before coating is irradiated with light or heated to chemically bond (for example, crosslink) the pulverized material in the coating film 20' together to form a void layer 20. The light irradiation or heating conditions in the chemical treatment step (3) are not particularly limited and are as described above.

[0260] On the other hand, although not shown in the figures, the adhesive layer of the present invention is manufactured separately by the adhesive layer manufacturing process described above. The adhesive layer manufacturing process (method for manufacturing the adhesive layer of the present invention) is, for example, as described above.

[0261] Furthermore, a bonding step (4) and an intermediate layer forming step (5) are performed. As described above, the intermediate layer forming step (5) is a heating step in which the adhesive layer 30 and the void layer 20 are heated after the bonding step (4). For example, if the adhesive is an adhesive composition containing a polymer (e.g., a (meth)acrylic polymer) and a crosslinking agent, the polymer may be crosslinked by the crosslinking agent in the heating step. The heating step may also serve as a drying step for the adhesive. Alternatively, the heating step may also serve as the intermediate layer forming step (5). The temperature of the heating step is not particularly limited, but is for example 70-160°C, 80-155°C, or 90-150°C. The duration of the heating step is not particularly limited, but is for example 1-10 minutes, 1-7 minutes, or 2-5 minutes.

[0262] Next, Figure 2 schematically shows an example of a slot die coating apparatus and a method for forming the void layer using the same. Note that Figure 2 is a cross-sectional view, but the hatches have been omitted for clarity.

[0263] As shown in the figure, each step in the method using this apparatus is carried out while the substrate 10 is conveyed in one direction by rollers. The conveying speed is not particularly limited and can be, for example, 1 to 100 m / min, 3 to 50 m / min, or 5 to 30 m / min.

[0264] First, a coating process (1) is performed in which the substrate 10 is fed out from the feed roller 101 and conveyed while the coating roll 102 coats the substrate 10 with sol particle liquid 20''. Subsequently, the process moves to a drying process (2) in the oven zone 110. In the coating apparatus of Figure 2, a pre-drying process is performed after the coating process (1) and prior to the drying process (2). The pre-drying process can be performed at room temperature without heating. In the drying process (2), a heating means 111 is used. As mentioned above, a hot air blower, a heating roll, a far-infrared heater, etc. can be used as appropriate for the heating means 111. Alternatively, for example, the drying process (2) may be divided into multiple processes, and the drying temperature may be increased in subsequent drying processes.

[0265] After the drying step (2), a chemical treatment step (3) is performed in the chemical treatment zone 120. In the chemical treatment step (3), for example, if the dried coating film 20' contains a photoactive catalyst, it is irradiated with light using lamps (light irradiation means) 121 placed above and below the substrate 10. Alternatively, for example, if the dried coating film 20' contains a thermally activated catalyst, a hot air blower (heating means) is used instead of the lamps (light irradiation devices) 121, and the substrate 10 is heated with hot air blowers 121 placed above and below the substrate 10. This crosslinking treatment causes chemical bonding between the pulverized materials in the coating film 20', and the void layer 20 is hardened and strengthened. In this example, the chemical treatment step (3) is performed after the drying step (2), but as mentioned above, there is no particular limitation on at which stage of the manufacturing method of the present invention the chemical bonding between the pulverized materials occurs. For example, as mentioned above, the drying step (2) may also serve as the chemical treatment step (3). Furthermore, even if the chemical bonding occurs in the drying process (2), a further chemical treatment process (3) may be performed to further strengthen the chemical bonding between the pulverized materials. Also, chemical bonding between the pulverized materials may occur in a process prior to the drying process (2) (for example, a pre-drying process, a coating process (1), a process for preparing a coating liquid (e.g., a suspension), etc.).

[0266] After the chemical treatment step (3), a bonding step (4) is performed in which the adhesive layer 30 is bonded onto the void layer 20 by bonding means 131a within the adhesive layer coating zone 130a. The bonding step (4) may be, for example, bonding (attaching) an adhesive tape or the like having the adhesive layer 30 on a substrate, as described above. The above description is not shown in the figures, but for example, as described above, the adhesive layer 30 may be peeled off and removed, or it may be left as is on the adhesive layer 30.

[0267] Furthermore, an intermediate layer formation process (aging process) (5) is performed in the intermediate layer formation zone (aging zone) 130, where the void layer 20 and the adhesive layer 30 react to form an intermediate layer 22. Also, as mentioned above, in this process, a cross-linking reaction occurs inside the void layer 20, resulting in a void layer 21 with improved strength. The intermediate layer formation process (aging process) (5) may be performed, for example, by heating the void layer 20 and the adhesive layer 30 using hot air blowers (heating means) 131 placed above and below the substrate 10. The heating temperature, time, etc., are not particularly limited, but are as described above, for example.

[0268] Then, after the intermediate formation process (aging process) (5), the laminate with the void layer 21 formed on the substrate 10 is wound up by the winding roll 105. In Figure 2, the void layer 21 of the laminate is covered and protected with a protective sheet unwound from the roll 106. Here, instead of the protective sheet, another layer formed from a long film may be laminated on top of the void layer 21.

[0269] Figure 3 schematically shows a microgravure coating apparatus and an example of a method for forming the void layer using the same. Note that although the figure is a cross-sectional view, the hatching has been omitted for clarity.

[0270] As shown in the figure, each step in the method using this apparatus is carried out while the substrate 10 is transported in one direction by rollers, similar to Figure 2. The transport speed is not particularly limited and can be, for example, 1 to 100 m / min, 3 to 50 m / min, or 5 to 30 m / min.

[0271] First, a coating process (1) is performed in which the substrate 10 is fed out from the feed roller 201 and conveyed while the substrate 10 is coated with a sol particle liquid 20''. The coating of the sol particle liquid 20'' is performed using a liquid reservoir 202, a doctor (doctor knife) 203, and a microgravure 204, as shown in the figure. Specifically, the sol particle liquid 20'' stored in the liquid reservoir 202 is attached to the surface of the microgravure 204, and then the microgravure 204 coats the surface of the substrate 10 while controlling the thickness to a predetermined level with the doctor 203. Note that the microgravure 204 is an example and is not limited to it; any other coating means may be used.

[0272] Next, a drying process (2) is performed. Specifically, as shown in the figure, the substrate 10 coated with the sol particle liquid 20'' is transported into the oven zone 210, and the sol particle liquid 20'' is dried by heating means 211 in the oven zone 210. The heating means 211 may be the same as in Figure 2, for example. Alternatively, the drying process (2) may be divided into multiple steps by dividing the oven zone 210 into multiple sections, and the drying temperature may be increased in subsequent drying steps. After the drying process (2), a chemical treatment process (3) is performed in the chemical treatment zone 220. In the chemical treatment process (3), for example, if the dried coating film 20' contains a photoactive catalyst, it is irradiated with light using lamps (light irradiation means) 221 placed above and below the substrate 10. Alternatively, for example, if the dried coating film 20' contains a thermally activated catalyst, a hot air blower (heating means) is used instead of a lamp (light irradiation device) 221, and the substrate 10 is heated by the hot air blowers (heating means) 221 positioned above and below the substrate 10. This crosslinking treatment causes chemical bonding between the pulverized materials in the coating film 20', forming a void layer 20.

[0273] After the chemical treatment step (3), a bonding step (4) is performed in which the adhesive layer 30 is bonded onto the void layer 20 by bonding means 231a within the adhesive layer coating zone 230a. The bonding step (4) may be, for example, bonding (attaching) an adhesive tape or the like having the adhesive layer 30 on a substrate, as described above. The above description is not illustrated, but for example, as described above, the adhesive layer 30 may be peeled off and removed, or it may be left on the adhesive layer 30.

[0274] Furthermore, an intermediate layer formation process (aging process) (5) is performed in the intermediate layer formation zone (aging zone) 230, where the void layer 20 and the adhesive layer 30 react to form an intermediate layer 22. Also, as mentioned above, in this process, the void layer 20 becomes a void layer 21 with improved strength. The intermediate layer formation process (aging process) (5) may be performed, for example, by heating the void layer 20 and the adhesive layer 30 using hot air blowers (heating means) 231 placed above and below the substrate 10. The heating temperature, time, etc., are not particularly limited, but are as described above, for example.

[0275] Then, after the intermediate formation process (aging process) (5), the laminated film with the void layer 21 formed on the substrate 10 is wound up by the winding roll 251. After that, for example, another layer may be laminated on the laminated film. Alternatively, before winding the laminated film up by the winding roll 251, for example, another layer may be laminated on the laminated film. [Examples]

[0276] Next, embodiments of the present invention will be described. However, the present invention is not limited to the following embodiments.

[0277] In the following reference examples, examples, and comparative examples, the number of parts (relative usage) of each substance is given in parts by mass (parts by weight) unless otherwise specified.

[0278] Furthermore, in the following reference examples, examples, and comparative examples, the storage modulus, porosity, thickness of each layer, weight-average molecular weight, and refractive index of the sol component of the adhesive layer at 23°C were measured using the measurement methods described below.

[0279] (Method for measuring the storage modulus) The storage modulus of the adhesive layer at 23°C was measured using the following method with the viscoelasticity measuring device ARES (product name of TA Instruments Co., Ltd.). Specifically, first, a sheet (layer) identical to the adhesive layer in each of the reference examples, examples, and comparative examples below was formed, except that it was a sheet with a thickness of 2 mm. This sheet was punched out to match a parallel plate with a diameter of 25 mm to create a measurement sample. This measurement sample was mounted in the chuck of the viscoelasticity measuring device ARES. Then, while applying strain with a period of 1 Hz, the temperature was increased from -70°C to 150°C at a heating rate of 5°C / min, and the storage modulus at 23°C was measured.

[0280] In the following reference examples, examples, and comparative examples, it is presumed that in the adhesive layers, the polymer (acrylic polymer) was crosslinked by the crosslinking agent upon heat drying of the coated adhesive, forming a crosslinked structure; however, the crosslinked structure has not been confirmed.

[0281] (Method for measuring the refractive index of the void layer before adhesive lamination) A substrate sample with a low refractive index layer was placed in an ellipsometer (JAWoollam Japan: VASE), and the refractive index was measured under conditions of a wavelength of 500 nm and an incident angle of 50 to 80 degrees. The average value was defined as the refractive index.

[0282] (Method for measuring the refractive index of a laminate after adhesive lamination) The prism of the device was attached to the substrate side of a laminate, which consisted of a prism coupler (manufactured by Metricon) with an adhesive bonded to an ultra-low refractive index layer. The critical angle of total internal reflection was measured using a laser, and the refractive index was calculated from the value of that critical angle.

[0283] (Method for measuring void ratio) As described above, the porosity was calculated from the measured refractive index using the Lorentz-Lorenz formula.

[0284] (Method for measuring thickness) The thickness of the adhesive layer was measured at five points using a dial gauge, and the average value was used. The thickness of the intermediate layer was defined as the portion with different contrast thicknesses between the adhesive layer and the low refractive index layer in the SEM image, and its thickness was measured at the average value of two points on the SEM image.

[0285] (Method for measuring the weight-average molecular weight of the sol component in adhesive layers) The weight-average molecular weight of the sol component and the percentage of low molecular weight components with a molecular weight of 10,000 or less were calculated from the molecular weight distribution curve measured by gel permeation chromatography (GPC). Specifically, first, measurement samples (each adhesive composition coated and then heat-dried) were prepared using the same method as the adhesive layers in each of the following reference examples, examples, and comparative examples. 200 mg of this measurement sample was mixed with 10 ml of tetrahydrofuran (THF), allowed to stand for 20 hours, and then filtered through a 0.45 μm membrane filter. Subsequently, the obtained filtrate was subjected to GPC measurement using the following measuring apparatus and conditions, and as described above, the weight-average molecular weight of the sol component and the percentage of low molecular weight components with a molecular weight of 10,000 or less were calculated from the molecular weight distribution curve. GPC measurement device: Product name "AQCUITY APC" (manufactured by Water Inc.) Column: Product name "G7000HxL+GMHxL+GMHxL" (manufactured by Tosoh Corporation) Eluent: Tetrahydrofuran (THF) Flow rate: 0.8mL / min Detector: Differential refractometer (RI) Column temperature (measurement temperature): 40℃ Injection volume: 100μL Standard: Polystyrene

[0286] (Method for measuring refractive index) The refractive index at a wavelength of 500 nm was measured using the method described above.

[0287] [Reference Example 1: Manufacturing of coating liquid for void layer formation] First, a gel having a porous structure (silicone porous material) was produced by performing gelation of a silicon compound (step (1) below) and maturation (step (2) below). Subsequently, the following steps were performed: (3) morphology control step, (4) solvent replacement step, (5) gel pulverization step, (6) modification reaction of nanoparticles with fluoroalkyl groups, and (7) mixing of the dispersion of fluoroalkyl group-modified nanoparticles to obtain a coating liquid for forming a void layer (liquid containing pulverized gel). In this reference example, step (3) morphology control step was performed as a separate step from step (1) below, as described below. However, the present invention is not limited thereto, and for example, step (3) morphology control step may be performed within step (1) below.

[0288] (1) Gelation of silicon compounds 9.5 kg of MTMS, a precursor of silicon compounds, was dissolved in 22 kg of DMSO. 5 kg of a 0.01 mol / L aqueous solution of oxalic acid was added to the mixture, and the mixture was stirred at room temperature for 120 minutes to hydrolyze the MTMS and produce tris(hydroxy)methylsilane.

[0289] To 55 kg of DMSO, 3.8 kg of 28% aqueous ammonia and 2 kg of pure water were added. Then, the hydrolyzed mixture was added and the mixture was stirred at room temperature for 15 minutes. After stirring for 15 minutes, the mixture was poured into a stainless steel container measuring 30 cm in length, 30 cm in width, and 5 cm in height, and allowed to stand at room temperature to gel tris(hydroxy)methylsilane, obtaining a gel-like silicon compound.

[0290] (2) Aging process The gel-like silicon compound obtained by the aforementioned gelation treatment was incubated at 40°C for 20 hours to mature it, thereby obtaining the rectangular parallelepiped-shaped gel mass.

[0291] (3) Morphological control process Water, which is the substitution solvent, was poured onto the gel synthesized in the 30cm × 30cm × 5cm stainless steel container by the above steps (1) and (2). Next, the cutting blade of the cutting jig was slowly inserted into the gel from above in the stainless steel container, and the gel was cut into a rectangular parallelepiped measuring 1.5cm × 2cm × 5cm.

[0292] (4) Solvent replacement step Next, the solvent replacement process was carried out as described in (4-1) to (4-3) below.

[0293] (4-1) After the "(3) Morphological control step" described above, the gel-like silicon compound was immersed in water eight times its weight and slowly stirred for 1 hour so that only the water was circulating. After 1 hour, the water was replaced with the same amount of water and stirred for a further 3 hours. After that, the water was replaced again and then heated at 60°C for 3 hours while slowly stirring.

[0294] (4-2) After (4-1), the water was replaced with isopropyl alcohol in an amount four times the weight of the gel-like silicon compound, and the mixture was heated at 60°C for 6 hours while stirring.

[0295] (4-3) After (4-2), isopropyl alcohol was replaced with the same weight of isobutyl alcohol, and the mixture was heated at 60°C for 6 hours to replace the solvent contained in the gel-like silicon compound with isobutyl alcohol. In this manner, a gel for producing a void layer was produced.

[0296] (5) Gel grinding process The gel (gel-like silicon compound) after the solvent replacement step (4) was subjected to a two-stage grinding process: a first stage using continuous emulsification dispersion (Milder MDN304, manufactured by Taiheiyo Kiko Co., Ltd.) and a second stage using high-pressure medialess grinding (Starburst HJP-25005, manufactured by Sugino Machine Co., Ltd.). For this grinding process, 26.6 kg of isobutyl alcohol was added to 43.4 kg of the solvent-substituted gel-like silicon compound, weighed, and then the first grinding stage was performed using circulating grinding for 20 minutes, followed by the second grinding stage at a grinding pressure of 100 MPa. In this way, an isobutyl alcohol dispersion (liquid containing the gel pulverized material) in which nanometer-sized particles (the pulverized gel) were dispersed was obtained. Furthermore, 224 g of a 1.5% solution of WPBG-266 (trade name, manufactured by Wako) methyl isobutyl ketone was added to 3 kg of the aforementioned gel pulverized material-containing liquid, followed by 67.2 g of a 5% solution of bis(trimethoxysilyl)ethane (manufactured by TCI) methyl isobutyl ketone. Then, 31.8 g of N,N-dimethylformamide was added and mixed to obtain the gel pulverized material-containing liquid.

[0297] (6) Modification reaction of nanoparticles with fluoroalkyl groups 0.06 g of 0.1 N (0.1 mol / L) aqueous HCl solution was mixed with 0.27 g of IPA (isopropyl alcohol) and stirred to obtain a homogeneous solution. 10 g of MIBK-ST (Nissan Chemical's product name: MIBK [methyl isobutyl ketone] dispersion of Si nanoparticles) was added to this solution, and then 0.7 g of trimethoxy(1H,1H,2H,2H-nonafluorohexyl)silane was added. The mixture thus obtained was heated and stirred at 60°C for 1 hour to carry out the modification reaction of the Si nanoparticles, and a fluoroalkyl group modified dispersion of the Si nanoparticles (modified nanoparticle dispersion) was obtained.

[0298] (7) Mixing of fluoroalkyl-modified dispersion of nanoparticles To the gel pulverized material-containing liquid produced by steps (1) to (5) above, 60 g of the fluoroalkyl-modified dispersion of Si nanoparticles (modified nanoparticle dispersion) produced by step (6) above was added to 3 kg to obtain a coating liquid for producing a void layer.

[0299] [Reference Example 2: Manufacturing of coating liquid for void layer formation] A coating solution for creating a void layer was prepared in the same manner as in Reference Example 1, except that 94% by mass of MTMS and 6% by mass of vinyltrimethoxysilane (manufactured by TCI) were used instead of the total mass (100% by mass) of MTMS in Reference Example 1 (i.e., 6% by mass of MTMS was replaced with vinyltrimethoxysilane).

[0300] [Reference Example 3: Manufacturing of adhesive coating liquid and adhesive layer] The adhesive coating liquid was manufactured as follows. Furthermore, an adhesive layer was manufactured using this adhesive coating liquid.

[0301] [Manufacturing of acrylic polymers] In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas inlet tube, and condenser, 90.7 parts butyl acrylate, 6 parts N-acryloylmorpholine, 3 parts acrylic acid, 0.3 parts 2-hydroxybutyl acrylate, and 0.1 parts by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator were charged together with 100 g of ethyl acetate. After introducing nitrogen gas and purging the mixture with nitrogen while gently stirring, the polymerization reaction was carried out for 8 hours while maintaining the temperature of the liquid in the flask at around 55°C to produce an acrylic polymer solution.

[0302] [Manufacturing of adhesive coating liquids] As described above, an acrylic adhesive solution was prepared by blending 0.15 parts of an isocyanate crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd.: product name "Coronate L", adduct of trimethylolpropane tolyleneisocyanate), 1.0 part of benzoyl peroxide (manufactured by Nippon Oil & Fats Co., Ltd.: product name "Nippon Oil & Fats Co., Ltd."), 0.075 parts of γ-glycidoxypropyl methoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.: product name "KBM-403"), and 8 parts of N-acryloylmorpholine with 100 parts of the solid content (all components other than the solvent) of the acrylic polymer solution prepared. The benzoyl peroxide is an organic peroxide. The N-acryloylmorpholine (ACMO) is a monomer that has one or two reactive double bonds in one molecule.

[0303] [Manufacturing of adhesive layers] As described above, the acrylic adhesive solution was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Polyester Films, thickness: 38 μm) so that the thickness of the adhesive layer after drying would be 10 μm. The adhesive layer for this reference example was then dried at 150°C for 3 minutes. The storage modulus G' of this adhesive layer at 23°C was 1.3 × 10⁻⁶. 5 That was the case.

[0304] [Reference Example 4: Manufacturing of adhesive coating liquid and adhesive layer] The adhesive coating liquid was manufactured as follows. Furthermore, an adhesive layer was manufactured using this adhesive coating liquid.

[0305] [Manufacturing of acrylic polymers] The same acrylic polymer solution was produced using the exact same method as in Reference Example 3, "Production of Acrylic Polymers."

[0306] [Manufacturing of adhesive coating liquids] As described above, an acrylic adhesive solution was prepared by adding 0.15 parts of an isocyanate crosslinking agent (manufactured by Nippon Polyurethane Industry Co., Ltd.: product name "Coronate L", an adduct of trimethylolpropane tolyleneisocyanate), 0.25 parts of benzoyl peroxide (manufactured by Nippon Oil & Fats Co., Ltd.: product name "Nipper BMT"), and 0.075 parts of γ-glycidoxypropyl methoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.: product name "KBM-403") to 100 parts of the solid content (all components other than the solvent) of the acrylic polymer solution prepared. In other words, the acrylic adhesive solution was prepared in the same manner as in Reference Example 3, "Preparation of Adhesive Coating Liquid," except that N-acryloylmorpholine was not added and the amount of benzoyl peroxide was changed.

[0307] [Manufacturing of adhesive layers] As described above, the acrylic adhesive solution prepared was applied to one side of a silicone-treated polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Polyester Films Co., Ltd., thickness: 38 μm) so that the thickness of the adhesive layer after drying would be 10 μm. The adhesive layer of this reference example was then dried at 150°C for 3 minutes. In other words, the adhesive layer of this reference example was prepared in the same manner as in "Preparation of the Adhesive Layer" of Reference Example 3, except that the acrylic adhesive solution of this reference example (Reference Example 4) was used instead of the acrylic adhesive solution of Reference Example 3. The storage modulus G' of this adhesive layer at 23°C is 1.3 × 10⁻⁶. 5 That was the case.

[0308] [Example 1] The void layer forming coating liquid prepared in Reference Example 1 was applied to an acrylic substrate and then dried to form a high void layer (void ratio 59 vol%) with a film thickness of approximately 850 nm. UV irradiation (450 mJ / cm²) was applied from the surface of the high void layer. 2 After performing the above steps, the 10 μm thick adhesive layer obtained in Reference Example 3 was bonded onto the high porosity layer surface, and aging was performed at 50°C for 30 hours to produce the laminate of the present invention in which the adhesive layer was directly laminated on one side of the void layer.

[0309] Furthermore, the manufactured laminate of the present invention was placed in a 60°C 90%RH oven and subjected to a 1000h heat and humidity durability test. The change in refractive index before and after the heat and humidity durability test was measured and compared. The results are shown in Table 1.

[0310] [Example 2] A laminate was manufactured in the same manner as in Example 1, except that the adhesive layer of Reference Example 4 was used instead of the adhesive layer of Reference Example 3, with the adhesive layer directly laminated on one side of the void layer. Furthermore, the manufactured laminate was subjected to a heating and humidification durability test of 1000 hours in a 60°C 90%RH oven, similar to the laminate of Example 1, and the change in refractive index before and after the heating and humidification durability test was measured and compared. The results are shown in Table 1.

[0311] [Example 3] A laminate was manufactured in the same manner as in Example 1, except that the ratio of MTMS to vinyltrimethoxysilane in the coating liquid for producing the void layer of Reference Example 2 was changed to 97% by mass of MTMS and 3% by mass of vinyltrimethoxysilane. Furthermore, the manufactured laminate was subjected to a heating and humidification durability test for 1000 hours in a 60°C 90%RH oven, similar to the laminate in Example 1, and the change in refractive index before and after the heating and humidification durability test was measured and compared. The results are shown in Table 1.

[0312] [Example 4] A laminate was manufactured in the same manner as in Example 1, except that the ratio of MTMS to vinyltrimethoxysilane in the coating liquid for producing the void layer of Reference Example 2 was changed to 90% by mass of MTMS and 10% by mass of vinyltrimethoxysilane. Furthermore, the manufactured laminate was subjected to a heating and humidification durability test for 1000 hours in a 60°C 90%RH oven, similar to the laminate in Example 1, and the change in refractive index before and after the heating and humidification durability test was measured and compared. The results are shown in Table 1.

[0313] [Comparative Example 1] A laminate was manufactured in the same manner as in Example 2, except that the coating liquid for manufacturing the void layer in Reference Example 1 was used instead of the coating liquid for manufacturing the void layer in Reference Example 2, with an adhesive layer directly laminated to one side of the void layer. Furthermore, the manufactured laminate was subjected to a heating and humidification durability test of 1000 hours in a 60°C 90%RH oven, similar to the laminate in Example 1, and the change in refractive index before and after the heating and humidification durability test was measured and compared. The results are shown in Table 1.

[0314] [Comparative Example 2] A laminate was manufactured in the same manner as in Example 1, except that the ratio of MTMS to vinyltrimethoxysilane in the coating liquid for producing the void layer of Reference Example 2 was changed to 50% by mass of MTMS and 50% by mass of vinyltrimethoxysilane. Furthermore, the manufactured laminate was subjected to a heating and humidification durability test for 1000 hours in a 60°C 90%RH oven, similar to the laminate in Example 1, and the change in refractive index before and after the heating and humidification durability test was measured and compared. The results are shown in Table 1.

[0315] In Table 1 below, "Remaining voids before and after durability test" represents the value obtained by dividing the void ratio (volume %) of the void layer after the heat-humidification durability test by the void ratio (volume %) of the void layer before the heat-humidification durability test. Furthermore, "Introduced double bond" represents the content (mass %) of vinyltrimethoxysilane relative to the total mass of MTMS and vinyltrimethoxysilane in the coating liquid for forming the void layer.

[0316] [Table 1]

[0317] As shown in Table 1 above, before the heat and humidity durability test, both the example and comparative example laminates had a high porosity of 52 volume% or more in the void layer, and as a result, the refractive index of the void layer was low, at 1.20 or less. After the heat and humidity durability test, all of the example laminates had a high void retention rate in the void layer, and as a result, the refractive index of the void layer remained low, at 1.21 or less. In contrast, the coating liquid for void layer formation does not contain vinyltrimethoxysilane (i.e., R 2 Comparative Example 1 (which did not contain a vinyl group as a base) and Comparative Example 2 (which had too high a vinyltrimethoxysilane content) both showed a low void retention rate in the void layer after the heat and humidity durability test, resulting in a high refractive index of the void layer. [Industrial applicability]

[0318] As described above, the present invention provides a void layer, a laminate, a method for manufacturing a void layer, an optical member, and an optical device in which adhesives or glues are less likely to penetrate the voids. The applications of the present invention are not particularly limited. For example, the optical device of the present invention is not particularly limited and includes image display devices, lighting devices, etc. Examples of the image display device include liquid crystal displays, organic EL displays, micro-LED displays, etc. Examples of the lighting device include organic EL lighting, etc. Furthermore, the applications of the void layer and laminate of the present invention are not limited to the optical member and optical device of the present invention and are arbitrary, and can be used in a wide range of applications.

[0319] This application claims priority based on Japanese Patent Application No. 2021-011080, filed on 27 January 2021, and incorporates all of its disclosures herein. [Explanation of Symbols]

[0320] 10 Base material 20 void layer 20' coating film (after drying) 20'' Sol Particle Liquid 21. Strengthened void layer 22 Middle Class 30 Adhesive layer 101 Feed roller 102 Coating Roll 110 Oven Zones 111 Hot air heater (heating means) 120 Chemical Processing Zone 121 Lamp (light irradiation means) or hot air blower (heating means) 130a Adhesive layer coating zone 130 Intermediate formation zone 131a Adhesive layer coating means 131 Hot air heater (heating means) 105 Reel Roll 106 rolls 201 Feed Roller 202 Liquid reservoir 203 Doctor (Doctor Knife) 204 Microgravure 210 Oven Zones 211 Heating means 220 Chemical Processing Zone 221 Light irradiation means or heating means 230a Adhesive layer coating zone 230 Intermediate formation zone 231a Adhesive layer coating method 231 Hot air heater (heating means) 251 Reel Roll

Claims

1. A void layer formed by chemically bonding particles together, The porosity of the aforementioned void layer is 35 volume% or more. The aforementioned particles are inorganic-organic composite particles in which an organic group is bonded to an inorganic compound. The aforementioned organic group is a linear or branched alkyl group R １ The group and the group R which contains a carbon-carbon unsaturated bond. ２ Includes the base, R １ Base and R ２ R for the sum of the bases ２ A void layer characterized by having a base molar ratio of 1 to 30 mol%.

2. The aforementioned R １ The void layer according to claim 1, wherein the group is a linear or branched alkyl group having 1 to 6 carbon atoms.

3. The aforementioned R ２ The base is the following chemical formula (R ２ The void layer according to claim 1 or 2, which is a group represented by ). 【Transform R2】 In the chemical formula (R ２ ), R ２１ , R ２２ and R ２３ Each of these is either a hydrogen atom or a linear or branched alkyl group, and they may be the same or different from each other. R ２４ This is either a linear or branched alkylene group, an oxycarbonyl group, an ether group, or a linear or branched alkylene oxycarbonyl group, or it is absent.

4. The aforementioned chemical formula (R ２ ) in R ２１ , R ２２ and R ２３ Each of these is either a hydrogen atom or a linear or branched alkyl group having 1 to 6 carbon atoms, and they may be the same or different from each other. R ２４ The void layer according to claim 3, wherein is a linear or branched alkylene group having 1 to 6 carbon atoms, an oxycarbonyl group, an ether group, or a linear or branched alkylene oxycarbonyl group having 1 to 7 carbon atoms, or is absent.

5. The aforementioned R ２ The base is CH ２ = CH - ien CH ２ = CH - (CH ２ ) １－６ - , CH ２ = C(CH ３ )-COO-, CH ２ =CH-O-, CH ２ = C(CH ３ )-COO-(CH ２ ) １－６ -, or CH ２ = C(CH ３ ) - CH ２ - The void layer according to any one of claims 1 to 4.

6. The void layer according to any one of claims 1 to 5, wherein the inorganic compound in the particles comprises at least one skeletal atom selected from the group consisting of Si, Mg, Al, Ti, Zn, and Zr.

7. The void layer according to any one of claims 1 to 6, which is a silicone porous material.

8. The void layer according to any one of claims 1 to 7, wherein the refractive index is 1.25 or less.

9. A void layer according to any one of claims 1 to 8, A glue-adhesive layer directly laminated on one or both sides of the void layer, A laminate characterized by containing the following.

10. An intermediate layer exists between the aforementioned void layer and the aforementioned adhesive layer. The laminate according to claim 9, wherein the intermediate layer is a layer formed by the union of the void layer and the adhesive layer.

11. The aforementioned adhesive layer is formed from an adhesive coating liquid containing a (meth)acrylic polymer, The laminate according to claim 9 or 10, wherein the (meth)acrylic polymer is a (meth)acrylic polymer having a weight-average molecular weight of 1.5 million to 2.8 million, obtained by polymerizing 3 to 10% by weight of a heterocyclic acrylic monomer, 0.5 to 5% by weight of (meth)acrylic acid, 0.05 to 2% by weight of a hydroxyalkyl (meth)acrylate, and 83 to 96.45% by weight of an alkyl (meth)acrylate as monomer components.

12. The laminate according to claim 11, wherein the (meth)acrylic polymer comprises a (meth)acrylic polymer crosslinked with a crosslinking agent.

13. The aforementioned adhesive layer is A step to prepare a viscous adhesive coating solution comprising a (meth)acrylic polymer, a monomer having one or two reactive double bonds in one molecule, an isocyanate crosslinking agent, and an organic peroxide, The adhesive coating step involves applying the adhesive coating liquid to the substrate, A heating and drying step in which the substrate to which the adhesive coating liquid has been applied is heated and dried, The laminate according to any one of claims 9 to 12, wherein the layer is formed by a method including the following:

14. The laminate according to claim 13, wherein the monomer having one or two reactive double bonds is a heterocyclic acrylate.

15. The storage modulus of the adhesive layer at 23°C is 1.0 × 10⁻⁶. ５ The laminate according to any one of claims 9 to 14.

16. The laminate according to any one of claims 9 to 15, wherein the refractive index is 1.25 or less after a heating and humidification durability test in which the laminate is held at a temperature of 60°C and a relative humidity of 90% for 1000 hours.

17. A coating step of coating a dispersion containing the aforementioned particles, A method for producing a void layer according to any one of claims 1 to 8, comprising a drying step of drying the coated dispersion.

18. An optical member comprising a void layer according to any one of claims 1 to 8 or a laminate according to any one of claims 9 to 16.

19. An optical apparatus comprising the optical member described in claim 18.

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