JP2024001067A - Laminate, optical member and optical device - Google Patents

Abstract

To provide a laminate of a gap layer and an adhesive layer which combines tack strength or adhesive force and difficult permeability of a tack agent or adhesive agent.SOLUTION: In order to achieve the above object, the first laminate of the present invention includes a void layer 20 and an adhesive layer 30, and the adhesive layer 30 is directly laminated on one or both surfaces of the void layer 20. The porosity of the void layer 20 is 35% by volume or more, and after a heating and humidifying durability test held at a temperature of 85°C. and a relative humidity of 85% for 500 hours, the void remaining percentage of the void layer 20 is 50% or more of that before the heating and humidifying durability test.SELECTED DRAWING: Figure 1

Description

The present invention relates to a laminate, an optical member, and an optical device.

In optical devices, for example, an air layer having a low refractive index is used as a total reflection layer. Specifically, for example, each optical film member (for example, a light guide plate and a reflection plate) in a liquid crystal device is laminated with an air layer in between. However, if each member is separated by an air layer, problems such as deflection of the member may occur, especially when the member is large. Furthermore, with the trend toward thinner devices, it is desired that each component be integrated. For this reason, each member is integrated with an adhesive without using an air layer (for example, Patent Document 1). However, if the air layer that plays the role of total reflection disappears, optical properties such as light leakage may deteriorate.

Therefore, it has been proposed to use a low refractive index layer instead of the air layer. For example, Patent Document 2 describes a structure in which a layer having a lower refractive index than the light guide plate is inserted between the light guide plate and the reflection plate. As the low refractive index layer, for example, a void layer having voids is used in order to have a low refractive index as close to that of air as possible.

Japanese Patent Application Publication No. 2012-156082 Japanese Patent Application Publication No. 10-62626

The void layer is used, for example, by being laminated with another layer via an adhesive layer. However, when a void layer and an adhesive layer are laminated, the adhesive or adhesive constituting the adhesive layer permeates into the voids of the void layer and fills the voids, resulting in a decrease in porosity. There is a risk that it will decrease. The higher the porosity of the void layer, the easier the pressure-sensitive adhesive or adhesive will penetrate. Further, in a high temperature environment, the adhesive or adhesive easily permeates into the void due to molecular movement of the adhesive or the adhesive.

In order to suppress or prevent the pressure-sensitive adhesive or adhesive from penetrating into the void, the pressure-sensitive adhesive or adhesive may have as high a modulus of elasticity as possible (hard). However, if the elastic modulus of the pressure-sensitive adhesive or adhesive is high (hard), there is a possibility that the adhesive force or adhesive force may be reduced. On the other hand, if the elastic modulus of the pressure-sensitive adhesive or adhesive is low (soft), high adhesive force or adhesive force can be easily obtained, but there is a possibility that the pressure-sensitive adhesive or adhesive will easily penetrate into the voids.

SUMMARY OF THE INVENTION Therefore, the present invention provides a laminate of a void layer and an adhesive layer, an optical member, and an optical device, which have both adhesive strength and difficulty in penetrating the adhesive or adhesive into voids. With the goal.

In order to achieve the above object, the first laminate of the present invention includes:
including a void layer and an adhesive layer,
The adhesive layer is directly laminated on one or both sides of the void layer,
The porosity of the void layer is 35% by volume or more,
After a heating/humidifying durability test held at a temperature of 85° C. and a relative humidity of 85% for 500 hours, the void remaining rate of the void layer is 50% by volume or more of that before the heating/humidifying durability test.

The second laminate of the present invention is
including a void layer and an adhesive layer,
The adhesive layer is directly laminated on one or both sides of the void layer,
The porosity of the void layer is 35% by volume or more,
The adhesive layer is formed of an adhesive containing a (meth)acrylic polymer and a crosslinking agent,
The gel fraction of the adhesive layer is 70% or more,
The thickness of the adhesive layer is 2 to 50 μm,
The adhesive layer is characterized in that it satisfies the following formula (I).

[(100-X)/100]×Y≦10 (I)

In the formula (I),
X is the gel fraction (%) of the adhesive layer,
Y is the thickness (μm) of the adhesive layer.

The third laminate of the present invention is
including a void layer and an adhesive layer,
The adhesive layer is directly laminated on one or both sides of the void layer,
The porosity of the void layer is 35% by volume or more,
The adhesive layer is formed of an adhesive containing a (meth)acrylic polymer and a crosslinking agent,
The (meth)acrylic polymer contains, as monomer components, 3 to 10% by weight of a heterocycle-containing acrylic monomer, 0.5 to 5% by weight of (meth)acrylic acid, and 0.05 to 2% by weight of hydroxyalkyl (meth)acrylate. , and 83 to 96.45% by weight of alkyl (meth)acrylate, and is characterized by being a (meth)acrylic polymer having a weight average molecular weight of 1.5 million to 2.8 million. Note that hereinafter, the first laminate of the present invention, the second laminate of the present invention, and the third laminate of the present invention may be collectively referred to as "the laminate of the present invention."

The optical member of the present invention is an optical member including the laminate of the present invention.

The optical device of the present invention is an optical device including the optical member of the present invention.

According to the present invention, there is provided a laminate of a void layer and an adhesive layer, an optical member, and an optical device that have both adhesive strength and adhesive strength and difficulty in penetrating the adhesive or adhesive into the void. can do.

FIG. 1 is a process 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. It is. FIG. 2 is a diagram schematically showing a part of the process in a method for manufacturing a roll-shaped laminated film (laminated film roll) and an example of an apparatus used therein. FIG. 3 is a diagram schematically showing a part of the process in the method for manufacturing a laminated film roll and another example of the apparatus used therein.

Next, the present invention will be explained in more detail by giving examples. However, the present invention is not limited in any way by the following explanation.

In the first laminate of the present invention, for example, the void remaining rate of the void layer after the heating and humidification durability test is higher than the void remaining ratio when only the void layer is subjected to the heating and humidification durability test. It may be more than 50% and less than 99%.

The first laminate of the present invention is, for example,
The void layer and the adhesive layer are laminated with an intermediate layer interposed therebetween,
The intermediate layer is a layer formed by combining a part of the void layer and a part of the adhesive layer,
The thickness of the intermediate layer is 200 nm or less,
After the heating and humidification durability test, the rate of increase in the thickness of the intermediate layer may be 500% or less with respect to the thickness of the intermediate layer before the heating and humidification durability test.

As described above, in the second laminate of the present invention, the value of [(100-X)/100]×Y expressed by the formula (I) is 10 or less. This means that in the adhesive layer, the amount of components that permeate into the void layer is small. Thereby, the phenomenon in which the voids in the void layer are filled and the porosity decreases can be suppressed or prevented. The gel fraction (X) of the adhesive is 70% or more as described above, and may be, for example, 75% or more or 80% or more. The upper limit of the gel fraction (X) is not particularly limited, but may be, for example, 100% or less, or 95% or less. The gel fraction (X) of the adhesive may be, for example, 75 to 95% or 80 to 95%. The thickness (Y) of the adhesive layer is 2 to 50 μm as described above, and may be, for example, 5 μm or more or 10 μm or more, and may be, for example, 40 μm or less or 30 μm or less. The thickness (Y) of the adhesive layer may be, for example, 5 to 40 μm or 10 to 30 μm.

The method for measuring the gel fraction (X) of the pressure-sensitive adhesive layer is not particularly limited, and can be measured, for example, by the measuring method described in Examples below. Further, the method for measuring the thickness (Y) of the adhesive layer is not particularly limited, but it can be measured, for example, by the measuring method described in the Examples below.

In the second laminate of the present invention, the gel fraction (X) of the adhesive layer, the thickness (Y) of the adhesive layer, and [(100- X)/100]×Y within the above-mentioned specific range, a laminate of a void layer and an adhesive layer that achieves both adhesive force or adhesion and difficulty in penetrating the adhesive into the voids. , an optical member and an optical device.

In the second laminate of the present invention, for example, when the molecular weight of the adhesive layer is measured by gel permeation chromatography, the weight average molecular weight of the sol component of the adhesive layer is 50,000 to 500,000. It may be. For example, in measuring the molecular weight of the adhesive layer by gel permeation chromatography, the content of low molecular weight components with a molecular weight of 10,000 or less in the sol portion of the adhesive layer is 20% by weight (mass% ) or less. By setting the weight average molecular weight of the sol component or the content of a low molecular weight component having a molecular weight of 10,000 or less in the sol component to the specific range, it is further made difficult for the adhesive to penetrate into the voids of the void layer. . The weight average molecular weight of the sol portion may be, for example, 70,000 or more, 450,000 or less, or 400,000 or less, for example, 70,000 to 450,000 or 70,000 to 400,000. Further, the content (ratio) of components having a molecular weight of 10,000 or less in the sol may be, for example, 20% by weight or less as described above, based on the total amount of the sol (100% by weight), for example. , 15% by weight or less, or 10% by weight or less. The lower limit of the content (proportion) of components having a molecular weight of 10,000 or less in the sol is not particularly limited, but may be, for example, 0% by weight or more or a value exceeding 0% by weight, for example, 3% by weight or more. But that's fine. The content (ratio) of components having a molecular weight of 10,000 or less in the sol may be, for example, 3 to 15% by weight or 3 to 10% by weight.

Note that the specific measuring method using gel permeation chromatography is not particularly limited, but may be, for example, the measuring method described in the Examples described later.

For example, in the second or third laminate of the present invention, after a heating and humidifying durability test in which the laminate is maintained at a temperature of 85° C. and a relative humidity of 85% for 500 hours, the void remaining ratio of the void layer is determined to be the same as that of the heating and humidifying durability test. It may be 50% by volume or more. Further, in the second or third laminate of the present invention, for example, the void remaining rate of the void layer after the heating and humidification durability test is such that when only the void layer is subjected to the heating and humidification durability test. The void residual rate may be more than 50% and less than 99%.

The second or third laminate of the present invention is, for example,
The void layer and the adhesive layer are laminated with an intermediate layer interposed therebetween,
The intermediate layer is a layer formed by combining a part of the void layer and a part of the adhesive layer,
The thickness of the intermediate layer may be 200 nm or less.

In the second or third laminate of the present invention, for example, after a heating and humidifying durability test of holding at a temperature of 85° C. and a relative humidity of 85% for 500 hours, the rate of increase in the thickness of the intermediate layer is determined by the heating and humidifying durability. It may be 500% or less of the thickness of the intermediate layer before the test.

In the laminate of the present invention, the void layer may have a refractive index of 1.25 or less, for example.

In the laminate of the present invention, for example, the adhesive layer may be formed of an optical acrylic adhesive having a total light transmittance of 85% or more and a haze of 3% or less. Note that the total light transmittance and haze of the adhesive layer can be measured, for example, by the same measuring method as for the laminate or void layer described later.

In the laminate of the present invention, the adhesive layer may have a storage modulus of 1.0×10 ⁵ or more at 23° C., for example. Note that the method for measuring the storage elastic modulus at 23° C. is not particularly limited, but it can be measured, for example, by the measuring method described in the Examples below.

In the second or third laminate of the present invention, the adhesive layer is formed of an adhesive containing a (meth)acrylic polymer and a crosslinking agent, as described above. In the adhesive layer, for example, the (meth)acrylic polymer may be crosslinked with the crosslinking agent to form a crosslinked structure.

The reason (mechanism) that the laminate of the present invention can achieve both adhesive strength and difficulty in penetrating the adhesive or adhesive into the voids is considered to be, for example, as follows. For example, by forming a pressure-sensitive adhesive layer using a specific pressure-sensitive adhesive, it is possible to achieve both high adhesive force or adhesive force and difficulty in penetrating the pressure-sensitive adhesive or adhesive into the void. More specifically, for example, by forming an adhesive layer using a specific adhesive as described above, a part of the void layer and a part of the adhesive layer are combined to form an intermediate layer. A layer is formed. Further, by using the above-mentioned specific adhesive, the intermediate layer does not spread excessively even under the conditions of the heating and humidification durability test. In addition, the intermediate layer acts as a stopper, and it is possible to suppress a decrease in porosity due to filling of the voids in the void layer 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-porosity layer will tend to become a strong and dense stopper, which will prevent the adhesive from reaching the high-porosity layer. Penetration is suppressed. However, these mechanisms are merely examples and do not limit the present invention in any way.

[1. Laminate, optical member and optical device]
As described above, the laminate of the present invention includes a void layer and an adhesive layer, and the adhesive layer is directly laminated on one or both surfaces of the void layer. In the present invention, when the adhesive layer is "directly laminated" on the void layer, the adhesive layer may be in direct contact with the void layer, or the adhesive layer may be directly laminated on the void layer. It may be laminated on the void layer via.

In the laminate of the present invention, after a heating and humidifying durability test in which the laminate is maintained at a temperature of 85° C. and a relative humidity of 85% for 500 hours, the void remaining ratio of the void layer is, for example, 50% compared to the voids before the heating and humidifying durability test. It may be vol.% or more, 55 vol.% or more, or 60 vol.% or more, and the upper limit is not particularly limited, but ideally it is 100 vol.%, and 99 vol.% or less, 98 vol.% or less, or 95 vol.% or more. It may be less than % by volume.

When the laminate of the present invention has the intermediate layer, as described above, the rate of increase in the thickness of the intermediate layer after the heating and humidification durability test is maintained at a temperature of 85° C. and a relative humidity of 85% for 500 hours, for example. The thickness of the intermediate layer before the humidification durability test may be 500% or less when the thickness of the intermediate layer before the heating and humidification durability test is taken as 100%. The rate of increase in the thickness of the intermediate layer after the heating and humidifying durability test is based on the thickness of the intermediate layer before the heating and humidifying durability test, with the thickness of the intermediate layer before the heating and humidifying durability test being 100%. Sometimes it may be, for example, 400% or less, 350% or less, or 300% or less, and may be, for example, 100% or more, 110% or more, 120% or more, 130% or more, or 140% or more.

In addition, in the laminate of the present invention, the void remaining rate of the void layer after the heating and humidification durability test is, for example, the percentage of voids remaining when only the void layer is subjected to the heating and humidification durability test, as described above. The percentage may be more than 50% and 99% or less, 53% or more, 55% or more, or 60% or more, and 98% or less, 97% or less, or 96% or less .

In the laminate of the present invention, for example, a laminate of the adhesive layer and the void layer, or a laminate of the adhesive layer, the intermediate layer, and the void layer has a light transmittance of 80% or more. There may be. Further, for example, the haze of the laminate 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 the upper limit is not particularly limited, but is ideally 100%, for example, 95% or more. % or less, 92% or less, 91% or less, or 90% or less. The haze of the laminate can be measured, for example, in the same manner as the haze of the void layer described below. Further, the light transmittance is a transmittance of light having a wavelength of 550 nm, and can be measured, for example, by the following measuring method.

(Method of measuring light transmittance)
The laminate is used as a sample to be measured using a spectrophotometer U-4100 (trade name of Hitachi, Ltd.). Then, the total light transmittance (light transmittance) of the sample is measured, assuming that the total light transmittance of air is 100%. The value of the total light transmittance (light transmittance) is a value measured at a wavelength of 550 nm.

In the laminate of the present invention, the adhesive force or adhesive force of the adhesive layer is, 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, for example. It may be 25 mm or more, 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 adhesive strength of the adhesive layer is not too low. Further, from the viewpoint of rework when reattaching, it is preferable that the adhesive force or adhesive force of the adhesive layer is not too high. The adhesive force or adhesion force of the pressure-sensitive adhesive layer can be measured, for example, as follows.

(Method of measuring adhesive strength or adhesive strength)
The laminated film of the present invention (the laminated body of the present invention is formed on a resin film base material) is sampled 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 (thickness 20 μm) was laminated to a PET film (T100: manufactured by Mitsubishi Plastic Film Co., Ltd.), and a piece of adhesive tape cut into 25 mm x 100 mm was pasted on the side opposite to the resin film of the laminated film of the present invention. Then, lamination with the PET film is performed. Next, the sample is chucked in an Autograph tensile tester (AG-Xplus, manufactured by Shimadzu Corporation) so that the distance between the chucks is 100 mm, and then a tensile test is performed at a tensile speed of 0.3 m/min. . The average test force of the 50 mm peel test is defined as the adhesive peel strength, that is, the adhesive force. Furthermore, adhesive strength can also be measured using the same measuring method. In the present invention, there is no clear distinction between "adhesive strength" and "adhesive strength".

The laminate of the present invention may be formed on a base material such as a film, for example. The film may be, for example, a resin film. Generally, a relatively small thickness is called a "film" and a relatively thick one is sometimes called a "sheet" to distinguish between them, but in the present invention, a "film" and a "sheet" are used. There shall be no particular distinction.

The base material is not particularly limited, and includes, for example, a base material made of thermoplastic resin, a base material made of glass, an inorganic substrate typified by silicone, a plastic molded from thermosetting resin, etc., an element such as a semiconductor, Carbon fiber materials such as carbon nanotubes can be preferably used, but the material is not limited thereto. Examples of the form of the base material include a film, a plate, and the like. Examples of the thermoplastic resin include polyethylene terephthalate (PET), acrylic, cellulose acetate propionate (CAP), cycloolefin polymer (COP), triacetylcellulose (TAC), polyethylene naphthalate (PEN), and polyethylene (PE). , polypropylene (PP), and the like.

The optical member of the present invention is not particularly limited, but may be, for example, an optical film containing the laminate of the present invention.

The optical device (optical device) of the present invention is not particularly limited, and may be, for example, an image display device or a lighting device. Examples of the image display device include a liquid crystal display, an organic EL (Electro Luminescence) display, a micro LED (Light Emitting Diode) display, and the like. Examples of the lighting device include organic EL lighting.

[2. void layer]
Hereinafter, the void layer (hereinafter sometimes referred to as "the void layer of the present invention") in the laminate of the present invention will be explained by giving an example. However, the void layer of the present invention is not limited to this.

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

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 a high void layer with a porosity of 60% by volume or more, for example.

The porosity can be measured, for example, by the following measuring method.

(Measurement method of porosity)
If the layer to be measured for porosity is a single layer containing voids, the ratio (volume ratio) of the layer's constituent materials to air can be determined using a standard method (for example, by measuring weight and volume to calculate density). ), it is possible to calculate the porosity (volume %). Furthermore, since there is a correlation between the refractive index and the porosity, the porosity can also be calculated from the value of the refractive index of the layer, for example. Specifically, for example, the porosity is calculated from the refractive index value measured with an ellipsometer using Lorentz-Lorenz's formula.

The void layer of the present invention can be produced, for example, by chemically bonding pulverized gel products (microporous particles), as described below. In this case, for convenience, the voids in the void layer can be divided into the following three types (1) to (3).

(1) Voids in the raw material gel itself (within particles) (2) Voids in the crushed gel product units (3) Voids between the crushed gel products caused by the accumulation of the crushed gel products

The voids in (2) above are defined when each particle group generated by pulverizing the gel is regarded as one block, regardless of the size of the pulverized gel product (microporous particles). In addition to the above (1) that may be formed within each block, there are voids formed during crushing. Moreover, the voids mentioned in (3) above are voids that occur due to irregularities in size, size, etc. of the gel pulverized product (microporous particles) during pulverization (for example, medialess pulverization, etc.). The voided layer of the present invention has appropriate porosity and peak pore diameter, for example, by having the voids described in (1) to (3) above.

Further, 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. If the void layer has a high porosity and the peak pore diameter is too large, light will be scattered and the layer will become opaque. Further, 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 method below.

(Method for measuring peak pore diameter)
Using a pore distribution/specific surface area measuring device (BELLSORP MINI/trade name of Microtrack Bell Co., Ltd.), the peak pore diameter is calculated from the results of calculating the BJH plot and BET plot due to nitrogen adsorption, and the isothermal adsorption line.

Further, the thickness of the void layer of the present invention is not particularly limited, and may be, for example, 100 nm or more, 200 nm or more, or 300 nm or more, or 10000 nm or less, 5000 nm or less, or 2000 nm or less.

For example, in the void layer of the present invention, as described later, by using a pulverized porous gel, the three-dimensional structure of the porous gel is destroyed, and a new three-dimensional structure different from the porous gel is created. is formed. In this way, the void layer of the present invention has a new pore structure (new void structure) that cannot be obtained in the layer formed from the porous gel, and thus has a high porosity. A void layer of scale can be formed. Further, in the case where the void layer of the present invention is a silicone porous material, for example, the pulverized materials are chemically bonded to each other while adjusting the number of siloxane bonding functional groups of the silicon compound gel. Further, after a new three-dimensional structure is formed as a precursor of the void layer, it is chemically bonded (e.g., cross-linked) in a bonding step. In the case of a body, it has a structure with voids, 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.

The void layer of the present invention includes, for example, a pulverized porous gel, and the pulverized materials are chemically bonded to each other, as described later. In the void layer of the present invention, the form of chemical bonding (chemical bonding) between the pulverized materials is not particularly limited, and specific examples of the chemical bonding include, for example, crosslinking. The method for chemically bonding the pulverized materials is as described in detail in the above-mentioned method for producing a void layer, for example.

The crosslinking bond is, for example, a siloxane bond. Examples of the siloxane bond include the following T2 bond, T3 bond, and T4 bond. When the silicone porous material of the present invention has a siloxane bond, for example, it may have any one type of bond, it may have any two types of bond, or it may have all three types of bond. Good too. The greater the ratio of T2 and T3 among the siloxane bonds, the greater the flexibility, and the properties inherent to gel can be expected, but the film strength becomes weaker. On the other hand, if the T4 ratio of the siloxane bonds is high, the membrane strength is likely to be developed, but the pore size becomes small and the flexibility becomes weak. For this reason, for example, it is preferable to change the T2, T3, and T4 ratios depending on the application.

When the void layer of the present invention has the siloxane bond, the ratio of T2, T3 and T4 is, for example, when T2 is expressed relatively as "1", T2:T3:T4=1:[1-100] :[0-50], 1:[1-80]:[1-40], 1:[5-60]:[1-30].

Further, it is preferable that the silicon atoms contained in the void layer of the present invention have siloxane bonds, for example. As a specific example, the proportion of unbonded silicon atoms (that is, residual silanol) among all the silicon atoms contained in the silicone porous body is, for example, less than 50%, 30% or less, or 15% or less.

The void layer of the present invention has, for example, a pore structure. In the present invention, the void size of a pore refers to the diameter of the long axis of the long axis and the diameter of the short axis of the void (hole). The pore 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, 20 nm or more, and the upper limit is, for example, 50 nm or less, 40 nm or less, 30 nm or less, and the range is, for example, 5 nm to 50 nm, 10 nm. ~40 nm. Since a preferable void size is determined depending on the use of the void structure, it is necessary to adjust the void size to a desired void size depending on the purpose, for example. The void size can be evaluated, for example, by the following method.

(Cross-sectional SEM observation of void layer)
In the present invention, the morphology of the void layer can be observed and analyzed using a SEM (scanning electron microscope). Specifically, for example, the void layer is subjected to FIB processing (accelerating voltage: 30 kV) under cooling, and the obtained cross-sectional sample is subjected to FIB-SEM (manufactured by FEI, trade name: Helios NanoLab 600, accelerating voltage: 1 kV). , a cross-sectional electron image can be obtained at an observation magnification of 100,000 times.

(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) was introduced into the capillary of a pore distribution/specific surface area measurement device (BELLSORP MINI/trade name of Microtrack Bell Co., Ltd.), and then the sample was incubated at room temperature for 24 hours. Vacuum drying is performed to degas the gas within the void structure. Then, by adsorbing nitrogen gas onto the sample, a BET plot, a BJH plot, and an adsorption isotherm are drawn to determine the pore distribution. This allows the void size to be evaluated.

In the porous layer of the present invention, the film density indicating the porosity is not particularly limited, and its lower limit is, for example, 1 g/cm ³ or more, 5 g/cm ³ or more, 10 g/cm ³ or more, 15 g/cm ³ or more. The upper limit is, for example, 50 g/cm ³ or less, 40 g/cm ³ or less, 30 g/cm ³ or less, 2.1 g/cm ³ or less, and the range is, for example, 5 to 50 g/cm ³ , 10 -40g/cm ³ , 15-30g/cm ³ , 1-2.1g/cm ³ .

The film density can be measured, for example, by the following method.

(Evaluation of film density)
After forming the void layer (the void layer of the present invention) on the acrylic film, the X-ray reflectance in the total reflection region was measured using an X-ray diffraction device (manufactured by RIGAKU: RINT-2000). After fitting the intensity and 2θ, the porosity (P%) is calculated from the total reflection critical angle of the void layer/base material. The film density can be expressed by the following formula.
Membrane density (%) = 100 (%) - porosity (P%)

The void layer of the present invention may have a pore structure (porous structure) as described above, for example, or may be an open-cell structure in which the pore structure is continuous. The open cell structure means, for example, that the pore structure is three-dimensionally connected in the void layer, and can also be said to be a state in which the internal voids of the pore structure are continuous. When the porous body has an open cell structure, it is possible to increase the porosity in the bulk, but when closed cell particles such as hollow silica are used, an open cell structure cannot be formed. In contrast, the void layer of the present invention has a three-dimensional dendritic structure in which the sol particles (pulverized porous gel forming the sol) have a three-dimensional dendritic structure. When the dendritic particles settle and accumulate in the sol coating film), it is possible to easily form an open cell structure. Moreover, it is more preferable that the void layer of the present invention forms a monolith structure in which the open cell structure has a plurality of pore distributions. The monolith structure refers to, for example, a structure in which nano-sized fine voids exist, and a hierarchical structure in which the nano-sized voids exist as an open cell structure. When forming the monolith structure, for example, fine voids provide membrane strength while coarse open voids provide high porosity, thereby making it possible to achieve both membrane strength and high porosity. In order to form such a monolithic structure, for example, it is important to first control the pore distribution of the generated pore structure in the porous gel before being pulverized into the pulverized material. Further, for example, when the porous gel is pulverized, the monolithic structure can be formed by controlling the particle size distribution of the pulverized material to a desired size.

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

The haze can be measured, for example, by the following method.

(Evaluation of haze)
The void layer (void layer of the present invention) is cut into a size of 50 mm x 50 mm, and the haze is measured by setting it in a haze meter (HM-150, manufactured by Murakami Color Research Institute). The haze value is calculated using the following formula.
Haze (%) = [diffuse transmittance (%) / total light transmittance (%)] × 100 (%)

Generally speaking, the refractive index of a medium is the ratio of the propagation speed of a wavefront of light in a vacuum to the propagation speed within a 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, 1.15 or less, and its lower limit is, for example, 1.05 or more, 1.06 or more, 1.07 or more, and the 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.

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

(Evaluation of refractive index)
After forming a void layer (the void layer of the present invention) on the acrylic film, it is cut into a size of 50 mm x 50 mm, and this is bonded to the surface of a glass plate (thickness: 3 mm) using an adhesive layer. A sample that does not reflect on the back surface of the glass plate is prepared by filling the center part (about 20 mm in diameter) of the back surface of the glass plate with black ink. The sample is set in an ellipsometer (manufactured by J.A. Woollam Japan: VASE), and the refractive index is measured at a wavelength of 500 nm and an incident angle of 50 to 80 degrees, and the average value is taken as the refractive index.

The thickness of the void layer of the present invention is not particularly limited, and the lower limit thereof is, for example, 0.05 μm or more and 0.1 μm or more, and the upper limit is, for example, 1000 μm or less, 100 μm or less, and the range is: For example, it is 0.05 to 1000 μm, 0.1 to 100 μm.

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

Although the method for manufacturing the void layer of the present invention is not particularly limited, it can be manufactured by, for example, the manufacturing method described below.

[3. Adhesive]
In the laminate of the present invention, the pressure-sensitive adhesive layer can be formed using at least one of a pressure-sensitive adhesive and an adhesive, for example. In the present invention, "adhesive" and "adhesive" are not necessarily clearly distinguishable, as will be described later. The adhesive is not particularly limited, but examples thereof include the adhesives listed below.

The adhesive used to form the adhesive layer in the laminate of the present invention has, for example, 3 to 10% by weight of a heterocycle-containing acrylic monomer as a monomer component, a polymerizable functional group, and (meth)acrylic acid. Based on a (meth)acrylic polymer containing 0.5 to 5% by weight, 0.05 to 2% by weight of hydroxyalkyl (meth)acrylate, and 83 to 96.45% by weight of alkyl (meth)acrylate. Used as a polymer.

As the heterocycle-containing acrylic monomer, for example, those having a polymerizable functional group and a heterocycle can be used without particular limitation. Examples of the polymerizable functional group include a (meth)acryloyl group and a vinyl ether group. Among these, a (meth)acryloyl group is preferred. Examples of the heterocycle include a morpholine ring, a piperidine ring, a pyrrolidine ring, and a piperazine ring. Examples of the heterocycle-containing acrylic monomer include N-acryloylmorpholine, N-acryloylpiperidine, N-methacryloylpiperidine, and N-acryloylpyrrolidine. Among these, N-acryloylmorpholine is preferred. Note that the heterocycle-containing acrylic monomer can improve the durability of both heat resistance and moisture resistance when the pressure-sensitive adhesive layer is made thin.

Moreover, a heterocycle-containing acrylic monomer is preferable in that it can improve the adhesion of the adhesive layer to the optical film. In particular, it is preferable in terms of improving the adhesive strength to cyclic polyolefins such as norbornene-based resins, and is suitable when a cyclic polyolefin is used as an optical film.

The heterocycle-containing acrylic monomer is used, for example, in an amount of 3 to 10% by weight based on the total amount of monomer components forming the (meth)acrylic polymer. The proportion of the heterocycle-containing acrylic monomer may be, for example, from 4 to 9.5% by weight or from 6 to 9% by weight. The proportion of the heterocycle-containing acrylic monomer is preferably not less than the above range from the viewpoint of heat resistance and moisture resistance when the pressure-sensitive adhesive layer is made thin. Further, the proportion of the heterocycle-containing acrylic monomer is preferably not greater than the above range from the viewpoint of moisture resistance when the thickness is reduced. Further, from the viewpoint of improving the adhesion properties of the pressure-sensitive adhesive layer, it is preferable that the proportion of the heterocycle-containing acrylic monomer is not greater than the above range. Further, from the viewpoint of adhesive strength, the proportion of the heterocycle-containing acrylic monomer is preferably not greater than the above range.

As (meth)acrylic acid, acrylic acid is particularly preferred.

(Meth)acrylic acid is used, for example, in a proportion of 0.5 to 5% by weight based on 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. The proportion of (meth)acrylic acid is preferably not less than the above range from the viewpoint of heat resistance when the pressure-sensitive adhesive layer (adhesive layer) is made thin. Further, the proportion of (meth)acrylic acid is preferably not greater than the above range from the viewpoint of heat resistance and moisture resistance when thinned. Further, from the viewpoint of adhesive strength, the proportion of (meth)acrylic acid is preferably not greater than the above range.

As the hydroxyalkyl (meth)acrylate, for example, those having a polymerizable functional group and a hydroxyl group can be used without particular limitation. Examples of the hydroxyalkyl (meth)acrylate include 2-hydroxyethyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 6-hydroxy Hydroxyalkyl (meth)acrylates such as hexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, and 12-hydroxylauryl (meth)acrylate are preferred.

Hydroxyalkyl (meth)acrylate is used, for example, in a proportion of 0.05 to 2% by weight based on the total amount of monomer components forming the (meth)acrylic polymer. The proportion of hydroxyalkyl (meth)acrylate may be, for example, from 0.075 to 1.5% by weight or from 0.1 to 1% by weight. The proportion of hydroxyalkyl (meth)acrylate is preferably not less than the above range from the viewpoint of heat resistance when the adhesive layer (adhesive layer) is made thinner. Further, the proportion of hydroxyalkyl (meth)acrylate is preferably not greater than the above range from the viewpoint of heat resistance and moisture resistance when thinned. Further, from the viewpoint of adhesive strength, the proportion of hydroxyalkyl (meth)acrylate is preferably not greater than the above range.

As the alkyl (meth)acrylate, for example, the alkyl group of the alkyl (meth)acrylate may have an average carbon number of about 1 to 12. Note that (meth)acrylate refers to acrylate and/or methacrylate, and (meth) in the present 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, and isononyl (meth)acrylate. , lauryl (meth)acrylate, etc., which can be used alone or in combination. Among these, alkyl (meth)acrylates in which the alkyl group has 1 to 9 carbon atoms are preferred.

The alkyl (meth)acrylate is used, for example, in a proportion of 83 to 96.45% by weight based on the total amount of monomer components forming the (meth)acrylic polymer. The alkyl (meth)acrylate is usually the remainder other than the heterocycle-containing acrylic monomer, (meth)acrylic acid, and hydroxyalkyl (meth)acrylate.

As monomer components forming the (meth)acrylic polymer, for example, in addition to the above monomers, any monomer other than the above may be used in an amount of 10% or less of the total amount of monomers, as long as the object of the present invention is not impaired. be able to.

Examples of the optional monomer include acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; styrenesulfonic acid, allylsulfonic acid, and 2-(meth)acrylamide-2-methylpropane. Sulfonic acid group-containing monomers such as sulfonic acid, (meth)acrylamidopropanesulfonic acid, sulfopropyl (meth)acrylate, and (meth)acryloyloxynaphthalene sulfonic acid; phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate, etc. . Examples include nitrogen-containing vinyl monomers. For example, maleimide, N-cyclohexylmaleimide, N-phenylmaleimide; (meth)acrylamide, N,N-dimethyl (meth)acrylamide, N,N-diethyl (meth)acrylamide, N-hexyl (meth)acrylamide, N - (N-substituted) amide monomers such as methyl (meth)acrylamide, N-butyl (meth)acrylamide, N-butyl (meth)acrylamide, N-methylol (meth)acrylamide, and N-methylolpropane (meth)acrylamide; Aminoethyl (meth)acrylate, Aminopropyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, t-Butylaminoethyl (meth)acrylate, 3-(3-pyrinidyl)propyl (meth)acrylate ) Alkylaminoalkyl (meth)acrylate monomers such as acrylate; Alkoxyalkyl (meth)acrylate monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; N-(meth)acryloyloxymethylene Examples include succinimide monomers such as succinimide, N-(meth)acryloyl-6-oxyhexamethylene succinimide, and N-(meth)acryloyl-8-oxyoctamethylene succinimide.

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

Furthermore, examples of copolymerizable monomers other than those mentioned above include silane monomers containing silicon atoms. Examples of the silane monomer include 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, and 8-vinyloctyltrimethoxysilane. , 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltriethoxysilane, 10-acryloyloxydecyltriethoxysilane, and the like.

The (meth)acrylic polymer used in the present invention may have a weight average molecular weight of 1.5 million to 2.8 million, for example. The weight average molecular weight may be, for example, 1.7 million to 2.7 million or 2 million to 2.5 million. The weight average molecular weight is preferably not smaller than the above range from the viewpoint of heat resistance and moisture resistance when the pressure-sensitive adhesive layer is made thin. Moreover, it is preferable that the weight average molecular weight is not larger than the above range from the viewpoint of the durability when thinned, bondability, and adhesive strength. In the present invention, the weight average molecular weight refers to a value measured by, for example, GPC (gel permeation chromatography) and calculated in terms of polystyrene.

The method for producing such a (meth)acrylic polymer is not particularly limited, and for example, known production methods such as solution polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations can be appropriately selected. Further, the obtained (meth)acrylic polymer may be a random copolymer, a block copolymer, a graft copolymer, or the like.

In addition, in solution polymerization, ethyl acetate, toluene, etc. are used as a polymerization solvent, for example. As a specific example of solution polymerization, the reaction is carried out under a flow of an inert gas such as nitrogen, a polymerization initiator is added, and the reaction is carried out at, for example, about 50 to 70° C. for about 5 to 30 hours.

The polymerization initiator, chain transfer agent, emulsifier, etc. used in radical polymerization are not particularly limited and can be appropriately selected and used. The weight average molecular weight of the (meth)acrylic polymer can be controlled by the amounts of the polymerization initiator and chain transfer agent used and the reaction conditions, and the amounts used are adjusted as appropriate depending on the types of these.

Examples of the polymerization initiator include 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'-dimethyleneisobutyramidine), 2,2 Azo initiators such as '-azobis[N-(2-carboxyethyl)-2-methylpropionamidine] hydrate (manufactured by Wako Pure Chemical Industries, Ltd., VA-057), persulfates such as potassium persulfate, ammonium persulfate, etc. , di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecanoate, t-hexylperoxydicarbonate Oxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxy-2-ethylhexanoate, di(4 -Peroxides such as methylbenzoyl peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane, t-butyl hydroperoxide, hydrogen peroxide, etc. Examples include, but are not limited to, initiators, redox initiators that combine peroxides and reducing agents, such as combinations of persulfates and sodium bisulfite, and combinations of peroxides and sodium ascorbate. It's not something you can do.

The polymerization initiators may be used alone or in combination 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 part by weight, based on 100 parts by weight of the monomer.

In addition, in order to produce a (meth)acrylic polymer having the above weight average molecular weight using, for example, 2,2'-azobisisobutyronitrile as a polymerization initiator, the amount of the polymerization initiator used is For example, the amount may be about 0.06 to 0.2 parts by weight or about 0.08 to 0.175 parts by weight based on 100 parts by weight of the total amount of the components.

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

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, sodium polyoxyethylene alkyl phenyl ether sulfate, and Examples include nonionic emulsifiers such as ethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene-polyoxypropylene block polymer. These emulsifiers may be used alone or in combination of two or more.

Further, as a reactive emulsifier, examples of emulsifiers into which radically polymerizable functional groups such as propenyl groups and allyl ether groups are introduced include Aquaron HS-10, HS-20, KH-10, BC-05, etc. , BC-10, BC-20 (all manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.), and Adekaria Soap SE10N (manufactured by Asahi Denka Kogyo Co., Ltd.). Reactive emulsifiers are preferred because they are incorporated into the polymer chain after polymerization, resulting in improved water resistance. The amount of emulsifier used is 0.3 to 5 parts by weight, more preferably 0.5 to 1 part by weight based on 100 parts by weight of the total amount of monomer components, from the viewpoint of polymerization stability and mechanical stability.

Moreover, it is preferable that the said adhesive is made into the adhesive composition containing a crosslinking agent. Examples of polyfunctional compounds that can be incorporated into the adhesive include organic crosslinking agents and polyfunctional metal chelates. Examples of organic crosslinking agents include epoxy crosslinking agents, isocyanate crosslinking agents, and imine crosslinking agents. As the organic crosslinking agent, isocyanate crosslinking agents are preferred. A polyfunctional metal chelate is one in which a polyvalent metal is covalently 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, Ti, etc. can give. Examples of atoms in organic compounds that form covalent bonds or coordinate bonds include oxygen atoms, and examples of organic compounds include alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, and ketone compounds.

Examples of the isocyanate-based crosslinking agent include aromatic isocyanates such as tolylene diisocyanate and xylene diisocyanate, alicyclic isocyanates such as isophorone diisocyanate, and aliphatic isocyanates such as hexamethylene diisocyanate.

More specifically, for example, lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate, alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate, 2,4-tolylene diisocyanate, Aromatic diisocyanates such as 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, and polymethylene polyphenylisocyanate, trimethylolpropane/tolylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Kogyo Co., Ltd., trade name Coronate L), Isocyanate adducts such as methylolpropane/hexamethylene diisocyanate trimer adduct (manufactured by Nippon Polyurethane Kogyo Co., Ltd., trade name Coronate HL), isocyanurate of hexamethylene diisocyanate (manufactured by Nippon Polyurethane Kogyo Co., Ltd., trade name Coronate HX), Examples include ether polyisocyanates, polyester polyisocyanates, adducts of these with various polyols, polyisocyanates polyfunctionalized with isocyanurate bonds, biuret bonds, allophanate bonds, etc.

The above isocyanate crosslinking agent may be used alone or in combination of two or more types, but the total content is based on 100 parts by mass of the (meth)acrylic polymer. The composition may contain, for example, 0.02 to 2 parts by weight, 0.04 to 1.5 parts by weight, or 0.05 to 1 part by weight of an isocyanate-based crosslinking agent. The content of the isocyanate-based crosslinking agent is preferably 0.02 parts by mass or more from the viewpoint of cohesive force, and on the other hand, from the viewpoint of suppressing or preventing a decrease in adhesive strength due to excessive crosslinking formation, it is preferably 2 parts by mass or less.

Furthermore, the adhesive may optionally contain tackifiers, plasticizers, fillers such as glass fibers, glass beads, metal powders, and other inorganic powders, pigments, colorants, fillers, antioxidants, etc. A UV absorber, a silane coupling agent, etc., and various additives may be used as appropriate without departing from the purpose of the present invention. It may also be an adhesive layer that contains fine particles and exhibits light diffusing properties.

[4. Manufacturing method of laminate]
Although the method for manufacturing the laminate of the present invention is not particularly limited, it can be performed, for example, by the manufacturing method described below. However, the following explanation is an example and does not limit the present invention in any way. Note that, hereinafter, the void layer that is a component of the laminate of the present invention may be referred to as "the void layer of the present invention". Furthermore, the method of manufacturing a void layer of the present invention may be referred to as "the method of manufacturing a void layer of the present invention."

[4-1. Manufacturing method of void layer]
Hereinafter, the method for manufacturing a void layer of the present invention will be explained by giving an example. However, the method for manufacturing a void layer of the present invention is not limited in any way by the following explanation.

The void layer of the present invention may be formed of, for example, a silicon compound. Further, the void layer of the present invention may be, for example, a void layer formed by chemical bonding between microporous particles. For example, the microporous particles may be pulverized gel.

In the method for producing a voided layer of the present invention, for example, the gel pulverization step for pulverizing the gel of the porous body may be performed in one step, but it is preferably performed in a plurality of pulverization steps. The number of pulverization stages is not particularly limited, and may be, for example, two stages or three or more stages.

In the present invention, the shape of the "particles" (for example, particles of the pulverized gel) is not particularly limited, and may be, for example, spherical or non-spherical. Further, in the present invention, the particles of the pulverized product may be, for example, sol-gel beads, nanoparticles (hollow nanosilica/nanoballoon particles), nanofibers, or the like.

In the present invention, for example, it is preferable that the gel is a porous gel, and it is preferable that the crushed product of the gel is porous, but the present invention is not limited thereto.

In the present invention, the gel pulverized product may have a structure having at least one of the shapes of particles, fibers, and flat plates, for example. The particulate and tabular structural units may be made of, for example, an inorganic substance. Furthermore, the constituent element of the particulate constituent unit may include, for example, at least one element selected from the group consisting of Si, Mg, Al, Ti, Zn, and Zr. The structure (constituent unit) forming the particulate shape may be a real particle or a hollow particle, and specific examples thereof include silicone particles, silicone particles having micropores, silica hollow nanoparticles, silica hollow nanoballoons, and the like. The fibrous structural unit is, for example, a nanofiber having a nano-sized diameter, and specific examples include cellulose nanofibers and alumina nanofibers. Examples of the plate-like structural unit include nanoclay, and specifically nano-sized bentonite (eg, Kunipia F [trade name]). The fibrous structural unit is not particularly limited, but includes, for example, carbon nanofibers, cellulose nanofibers, alumina nanofibers, chitin nanofibers, chitosan nanofibers, polymer nanofibers, glass nanofibers, and silica nanofibers. It may be at least one selected fibrous material.

In the method for producing a voided layer of the present invention, the gel pulverization step (for example, the plurality of pulverization steps, for example, the first pulverization step and the second pulverization step) may include, for example, ” You can go inside. Note that the details of the "other solvent" will be described later.

In addition, in the present invention, the "solvent" (for example, a gel manufacturing solvent, a void layer manufacturing solvent, a substitution solvent, etc.) does not need to dissolve the gel or its pulverized product. The pulverized product or the like may be dispersed or precipitated in the solvent.

The volume average particle size of the gel after the first grinding step may be, for example, 0.5-100 μm, 1-100 μm, 1-50 μm, 2-20 μm, or 3-10 μm. The volume average particle size of the gel after the second pulverization step may be, 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-containing liquid (gel-containing liquid). The volume average particle diameter may be measured using, for example, a particle size distribution evaluation device such as a dynamic light scattering method or a laser diffraction method, or an electron microscope such as a scanning electron microscope (SEM) or a transmission electron microscope (TEM). I can do it.

The method for producing a void layer of the present invention includes, for example, a gelling step of gelling a massive porous body in a solvent to obtain the gel. In this case, for example, in the first pulverizing step (for example, the first pulverizing step) of the plurality of pulverizing steps, the gel that has been gelled in the gelling step is used.

The method for producing a void layer of the present invention includes, for example, an aging step of aging the gelled gel in a solvent. In this case, for example, the gel after the aging step is used in the first pulverization step (for example, the first pulverization step) among the plurality of pulverization steps.

In the method for manufacturing a void layer of the present invention, for example, after the gelling step, the solvent replacement step of replacing the solvent with another solvent is performed. In this case, for example, the gel in the other solvent is used in the first pulverization step (for example, the first pulverization step) of the plurality of pulverization steps.

In at least one of the plurality of pulverizing steps (for example, at least one of the first pulverizing step and the second pulverizing step) of the method for manufacturing a voided layer of the present invention, for example, the shear viscosity of the liquid is measured. While controlling the pulverization of the porous body.

At least one of the plurality of pulverization steps (for example, at least one of the first pulverization step and the second pulverization step) of the method for producing a voided layer of the present invention is performed, for example, by high-pressure medialess pulverization.

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 a trifunctional or less saturated bond functional group.

In addition, hereinafter, in the method for producing a porous layer of the present invention, the gel-pulverized material-containing liquid obtained by the step including the gel-pulverizing step may be referred to as "gel-pulverized material-containing liquid of the present invention."

According to the gel pulverized material-containing liquid of the present invention, for example, by forming a coating film thereof and chemically bonding the pulverized materials in the coating film, the gel pulverized material-containing liquid can be used as a functional porous body according to the present invention. A void layer can be formed. According to the gel-pulverized product-containing liquid of the present invention, the void layer of the present invention can be applied to various objects, for example. Therefore, the gel-pulverized product-containing liquid of the present invention and the method for producing the same are useful, for example, in producing the void layer of the present invention.

The gel-pulverized product-containing liquid of the present invention has, for example, extremely excellent uniformity, so that, for example, when the void layer of the present invention is applied to an optical member or the like, it improves the appearance thereof. be able to.

The gel-pulverized material-containing liquid of the present invention can be used, for example, to obtain a layer (void layer) having a high porosity by applying the gel-pulverizing material-containing liquid onto a substrate and further drying it. It may also be a liquid containing pulverized gel. Further, the gel-pulverized material-containing liquid of the present invention may be, for example, a gel-pulverized material-containing liquid for obtaining a high-porosity porous body (a thick or massive bulk body). The bulk body can be obtained, for example, by performing bulk film formation using the liquid containing the pulverized gel material.

For example, the steps of manufacturing the liquid containing a pulverized gel product of the present invention, applying the liquid containing a pulverized gel product onto a substrate to form a coated film, and drying the coated film may be performed. The void layer of the present invention having a high porosity can be produced by the production method including.

Further, for example, the step of producing the gel pulverized material-containing liquid of the present invention, the step of feeding out the resin film in the form of a roll, and the step of coating the gel pulverized material-containing liquid on the rolled-out resin film. By a manufacturing method comprising a step of forming a film, a step of drying the coated film, and a step of winding up the laminated film in which the void layer of the present invention is formed on the resin film after the drying step. For example, as shown in FIGS. 2 and 3 described later, a roll-shaped laminated film (laminated film roll) can be manufactured.

[4-2. Gel pulverized product-containing liquid and its manufacturing method]
The pulverized gel-containing liquid of the present invention includes, for example, the pulverized gel obtained by the gel pulverization step (for example, the first pulverization step and the second pulverization step) and the other solvent.

The method for producing a voided layer of the present invention may include, for example, a plurality of gel pulverizing steps for pulverizing the gel (e.g., porous gel), as described above, for example, the first pulverizing step. step and said second grinding step. Hereinafter, the method for producing a gel-pulverized liquid-containing liquid according to the present invention will be mainly explained by taking as an example a case where the method includes the first pulverizing step and the second pulverizing step. Hereinafter, the case where the gel is a porous body (porous gel) will be mainly described. However, the present invention is not limited thereto, and the explanation for the case where the gel is a porous body (porous gel) can be applied analogously to cases other than the case where the gel is a porous body. Furthermore, hereinafter, the plurality of pulverization steps (for example, the first pulverization step and the second pulverization step) in the method for producing a voided layer of the present invention may be collectively referred to as a "gel pulverization step."

The gel-pulverized product-containing liquid of the present invention can be used, for example, to produce a functional porous body that exhibits the same function as an air layer (for example, low refractive properties), as described below. The functional porous body may be, for example, the void layer of the present invention. Specifically, the pulverized gel-containing liquid obtained by the production method of the present invention contains the pulverized porous gel, and the pulverized material has a structure in which the three-dimensional structure of the unpulverized porous gel is destroyed. , a new three-dimensional structure different from that of the unpulverized porous gel can be formed. For this reason, for example, a coating film (precursor of a functional porous material) formed using the liquid containing the pulverized gel material has new properties that cannot be obtained with a layer formed using the unpulverized porous gel. This becomes a layer in which a pore structure (new void structure) is formed. This allows the layer to perform the same function as the air layer (eg, similar low refractive properties). Further, the liquid containing a pulverized gel material of the present invention can be used, for example, after a new three-dimensional structure is formed as the coating film (precursor of a functional porous material) by the pulverized material containing residual silanol groups. , the pulverized materials can be chemically bonded to each other. Thereby, the formed functional porous body has a structure having voids, but can maintain sufficient strength and flexibility. Therefore, according to the present invention, functional porous bodies can be easily and simply applied to various objects. The gel-pulverized liquid-containing liquid obtained by the production method of the present invention is very useful, for example, in the production of the porous structure that can be used as a substitute for an air layer. Further, in the case of the air layer, it is necessary to form an air layer between the members by, for example, stacking the members with a gap provided between them by interposing a spacer or the like. However, the functional porous body formed using the gel-pulverized material-containing liquid of the present invention can exhibit the same function as the air layer simply by placing it at a desired site. Therefore, as described above, the same functions as the air layer can be imparted to various objects more easily and conveniently than by forming the air layer.

The gel-pulverized product-containing liquid of the present invention can also be referred to as, 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 liquid containing a pulverized gel product of the present invention, the porous body is a pulverized product thereof.

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

In addition, in the liquid containing the ground gel material of the present invention, the gel concentration of the ground material is not particularly limited, and for example, the gel concentration of the ground material is 2.5 to 4.5% by weight, 2.7 to 4.5% by weight, 2.7 to 4.5% by weight, 4.0% by weight, and 2.8 to 3.2% by weight.

In the gel-pulverized product-containing liquid of the present invention, the gel (for example, porous gel) is not particularly limited, and examples thereof include silicon compounds and the like.

The silicon compound is not particularly limited, but includes, for example, a silicon compound containing at least a trifunctional or less saturated bond functional group. The above-mentioned "contains 3 or less saturated bond functional groups" means that the silicon compound has 3 or less functional groups, and these functional groups are saturated bonded to silicon (Si). means.

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

In the formula (2), for example, X is 2, 3 or 4,
R ¹ and R ² are each a straight chain or branched alkyl group,
R ¹ and R ² may be the same or different,
When X is 2, R ¹ may be the same or different from each other,
R ² may be the same or different.

The above X and R ¹ are, for example, the same as X and R ¹ in formula (1) described below. Further, for the above-mentioned R ² , for example, the example of R ¹ in formula (1) described below can be used.

Specific examples of the silicon compound represented by the formula (2) include compounds represented by the following formula (2') in which X is 3. In the following formula (2'), R ¹ and R ² are each the same as in the above formula (2). When R ¹ and R ² are methyl groups, the silicon compound is trimethoxy(methyl)silane (hereinafter also referred to as "MTMS").

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

Examples of the organic solvent 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-normal-butyl ether, ethylene glycol monomethyl ether, xylene, cresol, chlorobenzene, isobutyl acetate, isopropyl acetate, isopentyl acetate, ethyl acetate, Normal-butyl acetate, normal-propyl acetate, normal-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, methyl cyclohexanol, methyl cyclohexanone, methyl-n-butyl ketone, isopentanol, and the like. Further, the dispersion medium may contain an appropriate amount of a perfluoro-based surfactant, a silicon-based surfactant, or the like that lowers the surface tension.

Examples of the gel pulverized product-containing liquid of the present invention include a sol particle liquid, which is the sol-like pulverized product dispersed in the dispersion medium. The gel-pulverized product-containing liquid of the present invention can be applied, for example, on a substrate and then chemically crosslinked in the bonding process described below to form a continuous film with a void layer having a film strength of a certain level or higher. It is possible to do so. In addition, "sol" in the present invention means that the three-dimensional structure of the gel is crushed, so that the crushed material (that is, particles of a porous sol with a nano three-dimensional structure that retains a part of the void structure) is dissolved in a solvent. This refers to a state where the liquid is dispersed and exhibits fluidity.

The liquid containing the pulverized gel of the present invention may contain, for example, a catalyst for chemically bonding the pulverized gel. 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 based on the weight of the pulverized gel. .

Further, the liquid containing the pulverized gel of the present invention may further contain, for example, a crosslinking aid for indirectly bonding the pulverized gel. The content of the crosslinking aid is not particularly limited, but is, for example, 0.01 to 20% by weight, 0.05 to 15% by weight, or 0.1 to 10% by weight based on the weight of the pulverized gel. It is.

In addition, in the gel pulverized product-containing liquid of the present invention, the proportion of functional groups that do not contribute to the crosslinked structure within the gel among the functional groups of the constituent unit monomers of the gel is, for example, 30 mol% or less, 25 mol% or less, 20 mol% or less. % or less, 15 mol% or less, for example, 1 mol% or more, 2 mol% or more, 3 mol% or more, 4 mol% or more. The proportion of functional groups that do not contribute to the crosslinked structure within the gel can be measured, for example, as follows.

(Method for measuring the proportion of functional groups that do not contribute to the crosslinked structure within the gel)
After drying the gel, solid-state NMR (Si-NMR) is measured, and the proportion of residual silanol groups that do not contribute to the crosslinked structure (functional groups that do not contribute to the crosslinked structure within the gel) is calculated from the NMR peak ratio. Furthermore, even when the functional group is other than a silanol group, the proportion of functional groups that do not contribute to the crosslinked structure within the gel can be calculated from the NMR peak ratio in accordance with this method.

Hereinafter, the method for producing a liquid containing a pulverized gel product of the present invention will be explained by giving examples. The following explanation can be used for the gel-pulverized product-containing liquid of the present invention unless otherwise specified.

In the method for producing a liquid containing pulverized gel of the present invention, the mixing step is a step of mixing the porous gel particles (pulverized material) and the solvent, and may or may not be present. A specific example of the mixing step is, for example, a step of mixing a dispersion medium with a ground product of a gel-like silicon compound (silicon compound gel) obtained from a silicon compound containing at least trifunctional or less saturated bond functional groups. Can be mentioned. In the present invention, the pulverized product of the porous gel can be obtained from the porous gel by a gel pulverizing step described below. Further, the pulverized porous gel can be obtained, for example, from the porous gel that has been subjected to an aging process, which will be described later.

In the method for producing a gel-pulverized product-containing liquid of the present invention, the gelling step is, for example, a step of gelling a lumpy porous body in a solvent to form the porous gel, and specific examples of the gelling step include: For example, it is a step of gelling the silicon compound containing at least trifunctional or less saturated bond functional groups in a solvent to produce a silicon compound gel.

In the following, the gelling step will be explained using an example in which the porous body is a silicon compound.

The gelling step is, for example, a step of gelling the silicon compound as a monomer 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, a residual silanol group, and the residual silanol group is preferably adjusted as appropriate depending on the chemical bond between the crushed silicon compound gels, which will be described later.

In the gelling step, the silicon compound is not particularly limited as long as it can be gelled by a dehydration condensation reaction. For example, the silicon compounds are bonded by the dehydration condensation reaction. The bond between the silicon compounds is, for example, a hydrogen bond or an intermolecular force bond.

Examples of the silicon compound include a silicon compound represented by the following formula (1). Since the silicon compound of formula (1) has a hydroxyl group, hydrogen bonding or intermolecular force bonding is possible between the silicon compounds of formula (1), for example, via each hydroxyl group.

In the formula (1), for example, X is 2, 3 or 4, and R ¹ is a straight chain or branched alkyl group. The number of carbon atoms in R ¹ is, for example, 1 to 6, 1 to 4, or 1 to 2. Examples of the straight-chain alkyl group include a methyl group, ethyl group, propyl group, butyl group, pentyl group, and hexyl group, and examples of the branched alkyl group include an isopropyl group and an isobutyl group. The X is, for example, 3 or 4.

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

Furthermore, specific examples of the silicon compound represented by the formula (1) include compounds where X is 4. In this case, the silicon compound is, for example, a tetrafunctional silane having four functional groups.

The silicon compound may be, for example, a precursor that forms the silicon compound of formula (1) by hydrolysis. The precursor may be anything that can produce the silicon compound by hydrolysis, and specific examples include the compound represented by the formula (2).

When the silicon compound is a precursor represented by the formula (2), the production method of the present invention may include, for example, a step of hydrolyzing the precursor prior to the gelling step.

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 dropping an aqueous solution of oxalic acid into the dimethyl sulfoxide solution of the silicon compound precursor at room temperature and then stirring the mixture for about 30 minutes. When hydrolyzing the silicon compound precursor, for example, by completely hydrolyzing the alkoxy group of the silicon compound precursor, subsequent heating and immobilization after gelation, aging, and void structure formation can be further improved. It can be expressed efficiently.

In the present invention, the silicon compound may be, for example, a hydrolyzate of trimethoxy(methyl)silane.

The silicon compound of the monomer is not particularly limited, and can be appropriately selected depending on the use of the functional porous body to be produced, for example. In the production of the functional porous body, the silicon compound is preferably the trifunctional silane because of its excellent low refractive index when low refractive index is important. ), the above-mentioned tetrafunctional silane is preferable because of its excellent scratch resistance. Moreover, the silicon compound serving as a raw material for the silicon compound gel may be used alone or in combination of two or more types, for example. As a specific example, the silicon compound may include only the trifunctional silane, only the tetrafunctional silane, or both the trifunctional silane and the tetrafunctional silane, or Furthermore, other silicon compounds may be included. When using two or more types of silicon compounds as the silicon compound, the ratio is not particularly limited and can be set as appropriate.

Gelation of the porous body such as the silicon compound can be performed, for example, by a dehydration condensation reaction between the porous bodies. 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 ammonia, potassium hydroxide, sodium hydroxide, ammonium hydroxide, etc. Examples include dehydration condensation catalysts such as base catalysts. The dehydration condensation catalyst may be an acid catalyst or a base catalyst, but a base catalyst is preferred. In the dehydration condensation reaction, the amount of the catalyst added to the porous body is not particularly limited; The amount is 0.1 to 5 moles.

The gelation of the porous material such as the silicon compound is preferably performed in a solvent, for example. The proportion of the porous body 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. Examples include glycol ethyl ether (EGEE). The number of the solvents may be, for example, one type, or two or more types may be used in combination. The solvent used for gelation is hereinafter also referred to as "gelling solvent."

The gelation conditions are not particularly limited. The processing temperature for the solvent containing the porous body is, for example, 20 to 30°C, 22 to 28°C, or 24 to 26°C, and the processing time is, for example, 1 to 60 minutes, 5 to 40 minutes, 10 to 30 minutes. It's a minute. When performing the dehydration condensation reaction, the treatment conditions are not particularly limited, and these examples can be used. By performing the gelation, when the porous body is a silicon compound, for example, siloxane bonds grow and primary particles of the silicon compound are formed, and as the reaction progresses, the primary particles A gel with a three-dimensional structure is produced in a string of beads.

The gel form of the porous body obtained in the gelling step is not particularly limited. The term "gel" generally refers to a solidified state in which solutes have a structure in which they have lost their independent mobility due to interactions and are aggregated. Among gels, wet gels generally contain a dispersion medium and the solute has a uniform structure in the dispersion medium, while xerogels have a network structure in which the solute has a network structure with voids after the solvent is removed. refers to something that takes In the present invention, it is preferable to use, for example, a wet gel as the silicon compound gel. When the porous gel is a silicon compound gel, the remaining amount of silanol groups in the silicon compound gel is not particularly limited, and can be similarly exemplified by the ranges described below.

The porous gel obtained by the gelation may be subjected to the solvent replacement step and the first pulverization step as it is, for example, but it may be subjected to an aging treatment in the aging step prior to the first pulverization step. It may be applied. In the aging step, the gelled porous body (porous gel) is aged in a solvent. In the aging step, the conditions for the aging treatment are not particularly limited, and for example, the porous gel may be incubated in a solvent at a predetermined temperature. According to the aging treatment, for example, for a porous gel having a three-dimensional structure obtained by gelation, the primary particles can be further grown, thereby making it possible to increase the size of the particles themselves. be. As a result, the contact state of the neck portion where the particles are in contact with each other can be increased from point contact to surface contact, for example. The porous gel subjected to the above aging treatment has, for example, increased strength of the gel itself, and as a result, the strength of the three-dimensional basic structure of the pulverized product after pulverization can be further improved. As a result, when a coating film is formed using the gel-pulverized product-containing liquid of the present invention, for example, even in the drying process after coating, the pore size of the pore structure in which the three-dimensional basic structure is deposited is Shrinkage due to volatilization of the solvent in the coating film that occurs in the drying process can be suppressed.

The temperature of the aging treatment 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; , for example, 30-80°C, 35-75°C, 40-70°C. The predetermined time is not particularly limited, and the lower limit thereof is, for example, 5 hours or more, 10 hours or more, or 15 hours or more, and the upper limit is, for example, 50 hours or less, 40 hours or less, or 30 hours or less. The range is, for example, 5 to 50 hours, 10 to 40 hours, or 15 to 30 hours. As for the optimal conditions for aging, for example, as described above, it is preferable to set the conditions to increase the size of the primary particles and increase the contact area of the neck portion in the porous gel. . Further, in the aging step, the temperature of the aging treatment preferably takes into account, for example, the boiling point of the solvent used. In the aging process, for example, if the aging temperature is too high, the solvent may evaporate excessively, and the coating liquid may become concentrated, causing problems such as closing of the pores of the three-dimensional pore structure. be. On the other hand, in the aging process, for example, if the aging temperature is too low, the effect of the aging will not be sufficiently obtained, and temperature variations over time in the mass production process will increase, leading to the possibility of producing products of inferior quality. There is.

The aging treatment can use, for example, the same solvent as the gelling step, and specifically, the aging treatment can be performed directly on the reaction product after the gel treatment (that is, the solvent containing the porous gel). preferable. When the porous gel is the silicon compound gel, the number of moles of residual silanol groups contained in the silicon compound gel that has undergone the aging treatment after gelation is, for example, based on the raw material used for gelation (for example, It is the proportion of residual silanol groups when the number of moles of alkoxy groups in the silicon compound (or its precursor) is taken as 100, and the lower limit thereof is, for example, 50% or more, 40% or more, or 30% or more, and the upper limit is , for example, 1% or less, 3% or less, 5% or less, and the range is, for example, 1 to 50%, 3 to 40%, 5 to 30%. For the purpose of increasing the hardness of the silicon compound gel, for example, it is preferable that the number of moles of residual silanol groups is as low as possible. If the number of moles of residual silanol groups is too high, for example, in the formation of the functional porous body, the void structure may not be maintained until the precursor of the functional porous body 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 body may not be able to be crosslinked, and sufficient film strength may not be imparted. The above is an example of residual silanol groups. For example, when using the silicon compound modified with various reactive functional groups as the raw material for the silicon compound gel, A similar phenomenon can also be applied.

The porous gel obtained by the gelation is, for example, subjected to an aging treatment in the aging step, then subjected to a solvent replacement step, and then subjected to the gel pulverization step. In the solvent replacement step, the solvent is replaced with another solvent.

In the present invention, the gel crushing step is a step of crushing the porous gel as described above. The pulverization may be performed, for example, on the porous gel after the gelling step, or may be further applied on the aged porous gel that has been subjected to the aging treatment.

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

Further, as described above, the gel is subjected to the solvent replacement step and then the gel crushing step is performed. In the solvent replacement step, the solvent is replaced 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 aging step, resulting in further gelation over time and the resulting gel pulverization. This is because there is a possibility that the pot life of the gel-containing liquid will be affected, and that the drying efficiency when drying a coating film formed using the gel-pulverized substance-containing liquid may be reduced. Note that the other solvent used in the gel pulverization process is hereinafter also referred to as a "pulverization solvent."

The pulverizing solvent (other solvent) is not particularly limited, and for example, an organic solvent can be used. Examples of the organic solvent include solvents having a boiling point of 140°C or lower, 130°C or lower, 100°C or lower, or 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 pulverizing solvent may be used alone or in combination of two or more.

In addition, in cases where the polarity of the grinding solvent is low, for example, the solvent replacement step is performed in a plurality of solvent replacement steps, and in the solvent replacement step, the later step is more effective than the earlier step. , the hydrophilicity of the other solvent may be lowered. By doing so, it is possible, for example, to improve the solvent replacement efficiency and to extremely reduce the residual amount of the gel manufacturing solvent (for example, DMSO) in the gel. As a specific example, for example, the solvent replacement step is performed in three solvent replacement steps, in which DMSO in the gel is first replaced with water in the first solvent replacement step, and then in the second solvent replacement step. Then, the water in the gel may be replaced with IPA, and further, in a third substitution step, the IPA in the gel may be replaced with isobutyl alcohol.

The combination of the gelling solvent and the grinding solvent is not particularly limited, and includes, for example, a combination of DMSO and IPA, a combination of DMSO and ethanol, a combination of DMSO and isobutyl alcohol, and a combination of DMSO and n-butanol. Examples include combinations of the following. By replacing the gelling solvent with the crushing solvent in this manner, a more uniform coating film can be formed, for example, in coating film formation described below.

The solvent replacement step is not particularly limited, but can be performed, for example, as follows. That is, first, the gel produced by the gel production process (for example, the gel after the aging treatment) is immersed or brought into contact with the other solvent, and the gel production catalyst in the gel and the alcohol component produced by the condensation reaction are removed. , water, etc., are dissolved in the other solvent. Thereafter, the solvent in which the gel was immersed or brought into contact is discarded, and the gel is immersed in or brought into contact with a new solvent again. This process is repeated until the remaining amount of the gel manufacturing solvent in the gel reaches the desired amount. The immersion time per time 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 is, for example, 10 hours or less. Further, the immersion in the solvent may be carried out by continuous contact of the gel with the solvent. Further, the temperature during the dipping is not particularly limited, but may be, for example, 20 to 70°C, 25 to 65°C, or 30 to 60°C. If heating is performed, the solvent replacement will proceed quickly and the amount of solvent required for the replacement will be small, but the solvent replacement may be simply performed at room temperature. Further, for example, when the solvent replacement step is performed in a plurality of solvent replacement steps, each of the plurality of solvent replacement steps may be performed as described above.

When the solvent replacement step is divided into a plurality of solvent replacement steps and the hydrophilicity of the other solvent is lower in the later step than in the first step, the other solvent (substitution solvent) is not particularly limited. In the last solvent replacement step, the other solvent (replacement solvent) is preferably a void layer manufacturing solvent. Examples of the solvent for producing the void layer include solvents having a boiling point of 140° C. or lower. Further, examples of the solvent for producing the void layer include alcohols, ethers, ketones, ester solvents, aliphatic hydrocarbon solvents, aromatic solvents, and the like. 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. It will be done. Specific examples of ethers having a boiling point of 140° C. or lower include propylene glycol monomethyl ether (PGME), methyl cellosolve, ethyl cellosolve, and the like. Specific examples of ketones having a boiling point of 140° C. or lower include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and the like. Specific examples of ester solvents having a boiling point of 140° C. or lower include ethyl acetate, butyl acetate, isopropyl acetate, normal propyl acetate, and the like. Specific examples of aliphatic hydrocarbon solvents having a boiling point of 140° C. or lower include hexane, cyclohexane, heptane, octane, and the like. Specific examples of aromatic solvents having a boiling point of 140° C. or lower include toluene, benzene, xylene, anisole, and the like. From the viewpoint of not easily corroding the base material (for example, a resin film) during coating, the solvent for producing the void layer is preferably an alcohol, ether, or aliphatic hydrocarbon solvent. Further, the number of the pulverizing solvents 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 have low volatility at room temperature. It is preferable from the aspect. In particular, in order to suppress the scattering of particles (for example, silica compounds) that are the material of the gel, it is preferable that the saturated vapor pressure of the solvent for producing the void layer is not too high (the volatility is not too high). As such a solvent, for example, a solvent having an aliphatic group having 3 or more carbon atoms is preferable, and a solvent having an aliphatic group having 4 or more carbon atoms is more preferable. The solvent having an aliphatic group having 3 or 4 or more carbon atoms may be, for example, alcohol. As such a solvent, specifically, for example, isopropyl alcohol (IPA), isobutyl alcohol (IBA), n-butanol, 2-butanol, 1-pentanol, and 2-pentanol are preferable, and in particular, isobutyl alcohol ( IBA) is preferred.

The other solvent (replacement solvent) used in steps other than the last solvent replacement step is not particularly limited, and examples thereof include alcohols, ethers, ketones, and the like. Specific examples of alcohol include isopropyl alcohol (IPA), ethanol, methanol, n-butanol, 2-butanol, isobutyl alcohol (IBA), pentyl alcohol, and the like. Specific examples of the ether include propylene glycol monomethyl ether (PGME), methyl cellosolve, ethyl cellosolve, and the like. Specific examples of ketones include acetone and the like. The other solvent (replacement solvent) may be used as long as it can replace the gel production solvent or the other solvent (replacement solvent) in the previous step. In addition, the other solvent (replacement solvent) other than the last solvent replacement step does not ultimately remain in the gel, or even if it remains, it is used on the base material (for example, a resin film) during coating. A solvent that does not easily corrode is preferable. From the viewpoint of not easily corroding the base material (for example, a resin film) during coating, the other solvent (replacement solvent) other than the last solvent replacement step is preferably alcohol. Thus, in at least one of the plurality of solvent replacement steps, the other solvent is preferably alcohol.

In the first solvent replacement step, the other solvent may be, for example, water or a mixed solvent containing water in any proportion. Water or a mixed solvent containing water has high compatibility with a highly hydrophilic gel production solvent (for example, DMSO), making it easy to replace the gel production solvent, and is also preferable from a cost perspective.

The plurality of solvent substitution steps include a step in which the other solvent is water, a step in which the other solvent is a solvent having an aliphatic group having a carbon number of 3 or less, and a step in which the other solvent is a solvent having an aliphatic group having a carbon number of 3 or less, and a step in which the other solvent is a solvent having an aliphatic group having a carbon number of 3 or less. The method may also include a step in which the other solvent is a solvent having an aliphatic group having 4 or more carbon atoms. Further, at least one of the solvent having an aliphatic group having 3 or less carbon atoms and the solvent having an aliphatic group having 4 or more carbon atoms may be an alcohol. The alcohol having an aliphatic group having 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 having 4 or more carbon atoms is not particularly limited, and examples thereof include n-butanol, 2-butanol, isobutyl alcohol (IBA), and pentyl alcohol. For example, the solvent having an aliphatic group having 3 or less carbon atoms may be isopropyl alcohol, and the solvent having an aliphatic group having 4 or more carbon atoms may be isobutyl alcohol.

The present inventors have found that it is very important to pay attention to the remaining amount of the solvent for gel production in order to form a porous layer with film strength under relatively mild conditions of, for example, 200°C or less. Ta. This finding is not disclosed in the prior art including the above-mentioned patent documents and non-patent documents, and is a finding uniquely discovered by the present inventors.

The reason (mechanism) why a void layer with a low refractive index can be produced by reducing the residual amount of the gel production solvent in the gel is unknown, but it is speculated as follows, for example. That is, as described above, the solvent for producing the gel is preferably a high boiling point solvent (for example, DMSO, etc.) in order to promote the gelation reaction. When the sol solution produced from the gel is coated and dried to produce a void layer, the above-mentioned It is difficult to completely remove high boiling point solvents. This is because if the drying temperature is too high or the drying time is too long, problems such as deterioration of the base material may occur. Then, the high boiling point solvent remaining during the coating and drying enters between the pulverized gel particles and causes the pulverized particles to slide against each other, causing the pulverized particles to pile up densely and reduce the porosity. Therefore, it is presumed that a low refractive index is difficult to develop. That is, on the contrary, it is considered that by reducing the residual amount of the high boiling point solvent, such a phenomenon can be suppressed and a low refractive index can be achieved. However, these are examples of presumed mechanisms and do not limit the present invention in any way.

In addition, in the present invention, the "solvent" (for example, a gel manufacturing solvent, a void layer manufacturing solvent, a substitution solvent, etc.) does not need to dissolve the gel or its pulverized product. The pulverized product or the like may be dispersed or precipitated in the solvent.

As mentioned above, the gel manufacturing solvent may have a boiling point of 140° C. or higher, for example.

The gel manufacturing solvent is, for example, a water-soluble solvent. In addition, in this invention, a "water-soluble solvent" refers to the solvent which can be mixed with water in arbitrary ratios.

When the solvent replacement step is performed by dividing into a plurality of solvent replacement steps, the method is not particularly limited, but each solvent replacement step can be performed, for example, as follows. That is, first, the gel is immersed in or brought into contact with the other solvent, and the catalyst for gel production, the alcohol component produced by the condensation reaction, water, etc. in the gel are dissolved in the other solvent. Thereafter, the solvent in which the gel was immersed or brought into contact is discarded, and the gel is immersed in or brought into contact with a new solvent again. This process is repeated until the remaining amount of the gel manufacturing solvent in the gel reaches the desired amount. The immersion time per time 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 is, for example, 10 hours or less. Further, the immersion in the solvent may be carried out by continuous contact of the gel with the solvent. Further, the temperature during the dipping is not particularly limited, but may be, for example, 20 to 70°C, 25 to 65°C, or 30 to 60°C. If heating is performed, the solvent replacement will proceed quickly and the amount of solvent required for the replacement will be small, but the solvent replacement may be simply performed at room temperature. In this solvent replacement step, the other solvent (replacement solvent) is gradually changed from a highly hydrophilic solvent to a less hydrophilic (highly hydrophobic) solvent and is repeated multiple times. In order to remove a highly hydrophilic gel manufacturing solvent (for example, DMSO, etc.), it is simple and efficient to first use water as a replacement solvent, for example, as described above. After removing DMSO and the like with water, the water in the gel is replaced, for example, with isopropyl alcohol⇒isobutyl alcohol (coating solvent). That is, since water and isobutyl alcohol have low compatibility, the solvent can be efficiently replaced by first replacing it with isopropyl alcohol and then replacing it with isobutyl alcohol, which is a coating solvent. However, this is an example, and as described above, the other solvent (substitution solvent) is not particularly limited.

In the present invention, the method for producing a gel includes, for example, as described above, in the solvent replacement step, the other solvent (replacement solvent) is gradually changed from a highly hydrophilic solvent to a less hydrophilic (highly hydrophobic) solvent. ) The procedure may be repeated multiple times by changing the solvent. According to this, as described above, the residual amount of the gel manufacturing solvent in the gel can be made extremely low. In addition, for example, the amount of solvent used can be kept to a much lower level and costs can be reduced, compared to performing solvent replacement in one step using only a coating solvent.

After the solvent replacement step, a gel pulverization step is performed in which the gel is pulverized in the pulverization solvent. For example, as described above, after the solvent replacement step and before the gel crushing step, the gel concentration may be measured if necessary, and after that, if necessary, the gel concentration adjustment step may be performed. good. The gel concentration measurement after the solvent replacement step and before the gel crushing step can be performed, for example, as follows. That is, first, after the solvent replacement step, the gel is taken out from the other solvent (pulverization solvent). This gel is controlled into a lump having an appropriate shape and size (for example, block shape) by, for example, the gel form control step. Next, after removing the solvent adhering to the gel mass, the solid content concentration in one gel mass is measured by a gravimetric drying method. At this time, in order to ensure the reproducibility of the measured values, measurements are performed on a plurality of (for example, six) randomly selected blocks, and the average value and variation in the values are calculated. In the concentration adjustment step, for example, the gel concentration of the gel-containing liquid may be lowered by further adding the other solvent (solvent for pulverization). Moreover, in the concentration adjustment step, the gel concentration of the gel-containing liquid may be increased by evaporating the other solvent (pulverization solvent).

In the method for producing a gel-pulverized liquid-containing liquid of the present invention, as described above, the gel-pulverizing step may be performed in one step, but it is preferably performed in a plurality of pulverizing steps. Specifically, for example, the first pulverization step and the second pulverization step may be performed. Further, the gel crushing step may further include a gel crushing step in addition to the first crushing step and the second crushing step. That is, in the manufacturing 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.

In the manner described above, a liquid (for example, a suspension) containing the microporous particles (pulverized gel-like compound) can be produced. Furthermore, after producing the liquid containing the microporous particles or during the production process, a catalyst that chemically bonds the microporous particles to each other is added, thereby producing a liquid containing the microporous particles and the catalyst. can do. The amount of the 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 based on the weight of the pulverized gel silicon compound. %. The catalyst may be, for example, a catalyst that promotes crosslinking between the microporous particles. The chemical reaction for chemically bonding the microporous particles to each other is preferably a dehydration condensation reaction of residual silanol groups contained in silica sol molecules. By promoting the reaction between the hydroxyl groups of the silanol groups with the catalyst, continuous film formation that hardens the pore structure in a short time is possible. Examples of the catalyst include photoactive catalysts and thermally active catalysts. According to the photoactive catalyst, for example, in the void layer forming step, the microporous particles can be chemically bonded (for example, crosslinked) to each other without heating. According to this, for example, in the void layer forming step, shrinkage of the void layer as a whole is less likely to occur, so that a higher porosity can be maintained. Further, 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 with light (photocatalyst generator) may be used, or in addition to or in place of the thermally active catalyst, a substance that generates a catalyst with light may be used. A substance that generates (thermal catalyst generator) may also be used. The photocatalyst generator is not particularly limited, but examples include photobase generators (substances that generate basic catalysts when irradiated with light), photoacid generators (substances that generate acidic catalysts when irradiated with light), and the like. , photobase generators are preferred. Examples of the photobase generator include 9-anthrylmethyl N,N-diethylcarbamate (trade name WPBG-018), (E)-1-[3-(2- (E)-1-[3-(2-hydroxyphenyl)-2-propenoyl]piperidine, trade name WPBG-027), 1-(anthraquinon-2-yl)ethyl imidazole carboxy rate (1-(anthraquinon-2-yl)ethyl imidazolecarboxylate, trade name WPBG-140), 2-nitrophenylmethyl 4-methacryloyloxypiperidine-1-carboxylate (trade name WPBG-165), 1,2-diisopropyl- 3-[Bis(dimethylamino)methylene]guanidium 2-(3-benzoylphenyl)propionate (trade name WPBG-266), 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidium n-butyl Triphenylborate (trade name WPBG-300), and 1,5,7-triazabicyclo[4.4.0]dec-5-ene 2-(9-oxoxanthen-2-yl)propionic acid (Tokyo Kasei Kogyo) Co., Ltd.), a compound containing 4-piperidinemethanol (trade name: HDPD-PB100: manufactured by Heraeus), and the like. Note that all of the product names including "WPBG" are product names of Wako Pure Chemical Industries, Ltd. Examples of the photoacid generator include aromatic sulfonium salts (product name SP-170: ADEKA), triarylsulfonium salts (product name CPI101A: Sun-Apro), aromatic iodonium salts (product name Irgacure250: Ciba Japan). company), etc. Further, the catalyst for chemically bonding the microporous particles to each other is not limited to the photoactive catalyst and the photocatalyst generator, and may be, for example, a thermally active catalyst or a thermal catalyst generator. Examples of the catalyst 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 to each other is, for example, added to the sol particle liquid (e.g., suspension) containing the pulverized material (microporous particles) immediately before coating. Alternatively, the catalyst or catalyst generator can be used as a mixed solution in which the catalyst or catalyst generator is mixed with a solvent. The liquid mixture may be, for example, a coating liquid that is directly added to and dissolved in the sol particle liquid, a solution in which the catalyst or catalyst generator is dissolved in a solvent, or a dispersion liquid in which the catalyst or catalyst generator is dispersed in a solvent. But that's fine. The solvent is not particularly limited, and examples thereof include water, buffer solutions, and the like.

Furthermore, for example, after preparing the liquid containing the microporous particles, by adding a small amount of a high boiling point solvent to the liquid containing the microporous particles, the appearance of the film during film formation by coating can be improved. It becomes possible. 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, particularly 0.0 times the solid content of the microporous particle-containing liquid. .15 times to 0.4 times the amount. The high boiling point solvent is not particularly limited, but includes, for example, dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), N,N-dimethylacetamide (DMAc), N-methylpyrrolidone (NMP), and γ- Examples include butyl lactone (GBL), ethylene glycol ethyl ether (EGEE), and the like. In particular, solvents having a boiling point of 110° C. or higher are preferred, but are not limited to the above specific examples. It is believed that the high boiling point solvent acts in place of a leveling agent during the formation of a film in which particles are arranged side by side. It is preferable to use the high boiling point solvent during gel synthesis as well. However, it is better to completely remove the solvent used during synthesis and then add the high boiling point solvent again after preparing the liquid containing the microporous particles, although the details are unknown, but it is more likely to work efficiently. Furthermore, the added high boiling point solvent remains in the membrane skeleton even after the membrane is formed, and is thought to have an effect on the penetration of the adhesive directly laminated onto the membrane into the voids within the membrane. That is, it is presumed that the slight difference in the solubility of the adhesive in the high boiling point solvent in the membrane is one of the factors that causes the difference in the penetration of the adhesive into the pores in the membrane. However, these mechanisms are illustrative and do not limit the present invention in any way.

[4-3. Manufacturing method of laminate, void layer, and adhesive layer]
Below, the method for manufacturing the laminate of the present invention will be explained by giving examples, together with the method for manufacturing the void layer and the adhesive layer that constitute the laminate. In the following, the case where the void layer of the present invention is a silicone porous body formed of a silicon compound will be mainly described. However, the void layer of the present invention is not limited to silicone porous bodies. When the void layer of the present invention is other than a silicone porous material, the following explanation can be applied mutatis mutandis unless otherwise specified.

The method for producing a void layer of the present invention includes, for example, a precursor forming step of forming a precursor of the void layer using the liquid containing the crushed gel product of the present invention, and the crushed gel contained in the precursor. The method includes a bonding step of chemically bonding the pulverized materials of the substance-containing liquid to each other. The precursor can also be referred to as a coating film, for example.

According to the method for manufacturing a void layer of the present invention, for example, a porous structure is formed that has the same function as an air layer. The reason for this is presumed to be as follows, for example, but the present invention is not limited to this speculation. Hereinafter, the case where the void layer of the present invention is a silicone porous body will be described as an example.

Since the liquid containing a ground gel product of the present invention used in the method for producing a porous silicone body contains the ground product of the silicon compound gel, the three-dimensional structure of the gel-like silica compound is dispersed into a three-dimensional basic structure. It is in a state of being Therefore, in the method for producing a porous silicone material, for example, when the precursor (e.g., coating film) is formed using the liquid containing the crushed gel material, the three-dimensional basic structure is deposited, and the three-dimensional basic structure is deposited. A void structure based on the structure is formed. That is, according to the method for producing a silicone porous body, a new three-dimensional structure is formed from the crushed product of the three-dimensional basic structure, which is different from the three-dimensional structure of the silicon compound gel. Furthermore, in the method for producing a silicone porous body, the new three-dimensional structure is fixed because the pulverized materials are chemically bonded to each other. Therefore, the silicone porous body obtained by the silicone porous body manufacturing method has a structure having voids, but can maintain sufficient strength and flexibility. The void layer (for example, silicone porous material) obtained by the present invention can be used as a member that utilizes voids in a wide range of products such as heat insulating materials, sound absorbing materials, optical members, and ink image receiving layers. Furthermore, laminated films with various functions can be produced.

For the method for producing a voided layer of the present invention, unless otherwise specified, the explanation of the gel-pulverized product-containing liquid of the present invention can be referred to.

In the step of forming the precursor of the porous body, for example, the liquid containing the pulverized gel of the present invention is applied onto the base material. The gel pulverized product-containing liquid of the present invention can be applied, for example, to a base material, and after drying the coating film, the pulverized products can be chemically bonded (for example, crosslinked) to each other in the bonding step. , it is possible to continuously form a void layer having a film strength of a certain level or higher.

The amount of the gel-pulverized product-containing liquid applied to the base material is not particularly limited, and can be appropriately set depending on, for example, the desired thickness of the void layer of the present invention. As a specific example, when forming the silicone porous body having a thickness of 0.1 to 1000 μm, the amount of the liquid containing the gel pulverized product applied to the base material is, for example, the amount of the gel pulverized product-containing liquid per 1 m ² of the base material area. They are 0.01 to 60000 μg, 0.1 to 5000 μg, and 1 to 50 μg. The preferred coating amount of the gel-pulverized liquid-containing liquid is difficult to define unambiguously because it is related to, for example, the concentration of the liquid and the coating method, but considering productivity, it is recommended to apply the coating in as thin a layer as possible. It is preferable to do so. If the coating amount is too large, for example, there is a high possibility that the coating will be dried in a drying oven before the solvent evaporates. As a result, the solvent dries before the nano-pulverized sol particles settle and accumulate in the solvent to form a pore structure, which may inhibit the formation of pores and significantly reduce the porosity. On the other hand, if the coating amount is too thin, there is a possibility that there is a high risk of coating repellency due to unevenness of the base material, variations in hydrophilic and hydrophobic properties, etc.

After applying the liquid containing the pulverized gel material to the base material, the precursor (coated film) of the porous body may be subjected to a drying treatment. By the drying process, for example, not only the solvent in the precursor of the porous body (the solvent contained in the gel-pulverized material-containing liquid) is removed, but also the sol particles are precipitated and deposited during the drying process, and the voids are closed. The purpose is to form a structure. The temperature of the drying process is, for example, 50 to 250°C, 60 to 150°C, or 70 to 130°C, and the time of the drying process is, for example, 0.1 to 30 minutes, 0.2 to 10 minutes, 0. .3 to 3 minutes. Regarding the drying temperature and time, lower and shorter drying times are preferable, for example, in relation to continuous productivity and development of high porosity. If the conditions are too harsh, for example, when the base material is a resin film, the base material will expand in the drying oven as it approaches the glass transition temperature of the base material, and the film formed immediately after coating. Defects such as cracks may occur in the void structure. On the other hand, if the conditions are too lenient, for example, the product may contain residual solvent when it leaves the drying oven, which may cause visual defects such as scratches when it rubs against the rolls in the next process. be.

The drying treatment may be, for example, natural drying, heating drying, or reduced pressure 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, and a far-infrared heater. Among these, when continuous industrial production is assumed, it is preferable to use heat drying. Regarding the solvent used, a solvent with a low surface tension is preferable in order to suppress the generation of shrinkage stress due to solvent volatilization during drying and the resulting cracking of the void layer (the silicone porous material). Examples of the solvent include, but are not limited to, lower alcohols such as isopropyl alcohol (IPA), hexane, perfluorohexane, and the like.

The base material is not particularly limited, and includes, for example, a base material made of thermoplastic resin, a base material made of glass, an inorganic substrate typified by silicone, a plastic molded from thermosetting resin, etc., an element such as a semiconductor, Carbon fiber materials such as carbon nanotubes can be preferably used, but the material is not limited thereto. Examples of the form of the base material include a film, a plate, and the like. Examples of the thermoplastic resin include polyethylene terephthalate (PET), acrylic, cellulose acetate propionate (CAP), cycloolefin polymer (COP), triacetylcellulose (TAC), polyethylene naphthalate (PEN), and polyethylene (PE). , polypropylene (PP), and the like.

In the method for producing a void layer of the present invention, the bonding step is a step of chemically bonding the pulverized materials contained in the precursor (coating film) of the porous body. Through the bonding step, for example, the three-dimensional structure of the pulverized material in the precursor of the porous body is fixed. When conventional immobilization is performed by sintering, for example, high temperature treatment of 200° C. or higher is performed to induce a dehydration condensation reaction of silanol groups and the formation of siloxane bonds. In the bonding step of the present invention, by reacting various additives that catalyze the dehydration condensation reaction, for example, when the base material is a resin film, the temperature can be increased to around 100°C without causing damage to the base material. With a relatively low drying temperature and a short processing time of less than a few minutes, a void structure can be continuously formed and fixed.

The method of chemically bonding is not particularly limited, and can be appropriately determined depending on the type of gel (eg, silicon compound gel), for example. As a specific example, the chemical bonding can be performed, for example, by chemical cross-linking between the pulverized materials, and inorganic particles such as titanium oxide may be added to the pulverized materials. In this case, chemically crosslinking the inorganic particles and the pulverized material may be considered. Furthermore, when a biocatalyst such as an enzyme is supported, a site other than the catalytic active site and the pulverized material may be chemically crosslinked. Therefore, the present invention can be applied not only to the void layer formed by the sol particles, but also to organic-inorganic hybrid void layers, host-guest void layers, etc., but is not limited thereto.

The bonding step can be performed, for example, by a chemical reaction in the presence of a catalyst, depending on the type of the pulverized gel (eg, silicon compound gel). As the chemical reaction in the present invention, it is preferable to utilize a dehydration condensation reaction of residual silanol groups contained in the pulverized silicon compound gel. By promoting the reaction between the hydroxyl groups of the silanol groups with the catalyst, continuous film formation that hardens the pore structure 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. The catalyst for the dehydration condensation reaction is particularly preferably a base catalyst. Furthermore, photoacid generating catalysts, photobase generating catalysts, and the like, which exhibit catalytic activity by irradiation with light (for example, ultraviolet light), can also be preferably used. The photoacid generating catalyst and the photobase generating catalyst are not particularly limited, but are, for example, as described above. For example, as described above, the catalyst is preferably used by being added to the sol particle liquid containing the pulverized material immediately before coating, or it is preferably used as a mixture of the catalyst and a solvent. The mixed liquid may be, for example, a coating liquid directly added to and dissolved in the sol particle liquid, a solution in which the catalyst is dissolved in a solvent, or a dispersion in which the catalyst is dispersed in a solvent. The solvent is not particularly limited, and as described above, examples thereof include water, buffer solutions, and the like.

Furthermore, for example, a crosslinking aid may be added to the gel-containing liquid of the present invention for indirectly bonding the pulverized gels together. This cross-linking auxiliary agent enters between the particles (the pulverized material), and the particles and the cross-linking auxiliary agent interact or bond with each other, thereby making it possible to bond particles that are somewhat distant from each other, It becomes possible to increase the strength efficiently. The crosslinking aid is preferably a multi-crosslinked silane monomer. Specifically, the multi-crosslinked silane monomer may have, for example, 2 or more and 3 or less alkoxysilyl groups, the chain length between the alkoxysilyl groups may be 1 or more and 10 or less carbon atoms, and an element other than carbon. may also be included. Examples of the crosslinking aid include bis(trimethoxysilyl)ethane, bis(triethoxysilyl)ethane, bis(trimethoxysilyl)methane, bis(triethoxysilyl)methane, bis(triethoxysilyl)propane, and bis(triethoxysilyl)propane. (trimethoxysilyl)propane, bis(triethoxysilyl)butane, bis(trimethoxysilyl)butane, bis(triethoxysilyl)pentane, bis(trimethoxysilyl)pentane, bis(triethoxysilyl)hexane, bis(trimethoxysilyl)butane, methoxysilyl)hexane, bis(trimethoxysilyl)-N-butyl-N-propyl-ethane-1,2-diamine, tris-(3-trimethoxysilylpropyl)isocyanurate, tris-(3-triethoxysilylpropyl) ) isocyanurate, etc. The amount of this crosslinking aid added is not particularly limited, but is, for example, 0.01 to 20% by weight, 0.05 to 15% by weight, or 0.1 to 10% by weight based on the weight of the pulverized silicon compound. Weight%.

The chemical reaction in the presence of the catalyst can be carried out, for example, by irradiating or heating the coated film containing the catalyst or catalyst generator that has been added to the gel-pulverized material-containing solution in advance, or by This can be carried out by spraying the catalyst and then irradiating light or heating, or by irradiating light or heating while spraying the catalyst or catalyst generator. For example, when the catalyst is a photoactive catalyst, the microporous particles can be chemically bonded to each other by light irradiation to form the silicone porous body. Further, when the catalyst is a thermally activated catalyst, the microporous particles can be chemically bonded to each other by heating to form the silicone porous body. The light irradiation amount (energy) in the light irradiation is not particularly limited, but is, for example, 200 to 800 mJ/cm ² , 250 to 600 mJ/cm ² , or 300 to 400 mJ/cm ² in terms of @360 nm. From the viewpoint of preventing insufficient irradiation and decomposition of the catalyst generator due to light absorption, resulting in insufficient effects, an integrated light amount of 200 mJ/cm ² or more is preferable. Further, from the viewpoint of preventing damage to the base material under the void layer and generation of heat wrinkles, an integrated light amount of 800 mJ/cm ² or less is preferable. The wavelength of the light in the light irradiation is not particularly limited, and is, for example, 200 to 500 nm or 300 to 450 nm. The light irradiation time in the light irradiation is not particularly limited, and is, for example, 0.1 to 30 minutes, 0.2 to 10 minutes, or 0.3 to 3 minutes. The conditions for the heat treatment are not particularly limited, and the heating temperature is, for example, 50 to 250°C, 60 to 150°C, or 70 to 130°C, and the heating time is, for example, 0.1 to 30 minutes. 0.2 to 10 minutes, 0.3 to 3 minutes. Regarding the solvent used, for example, a solvent with a low surface tension is preferable 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, perfluorohexane, and the like.

In the manner described above, the void layer (for example, silicone porous material) of the present invention can be manufactured. However, the method for manufacturing a void layer of the present invention is not limited to the above. Note that the void layer of the present invention, which is a porous silicone material, may be referred to as "the porous silicone material of the present invention" below.

Furthermore, in manufacturing the laminate of the present invention, an adhesive layer is further formed on the void layer of the present invention (adhesive layer forming step). Specifically, for example, the pressure-sensitive adhesive layer may be formed by applying (coating) a pressure-sensitive adhesive or an adhesive onto the void layer of the present invention. Further, by laminating the adhesive layer side of an adhesive tape, etc. in which the adhesive layer is laminated on a base material, onto the void layer of the present invention, the adhesive layer may be laminated onto the void layer of the present invention. An adhesion layer may be formed. In this case, the base material such as the adhesive tape may be left attached as is or may be peeled off from the adhesive layer. In particular, as mentioned above, by peeling off the base material to create a void layer-containing adhesive sheet that does not have a base material (base material-less), the thickness can be significantly reduced, and the thickness of devices, etc. The increase can be suppressed. In the present invention, "adhesive" and "adhesive layer" refer to, for example, an agent or layer intended to be re-peelable from an adherend. In the present invention, "adhesive" and "adhesive layer" refer to, for example, an agent or layer that is not intended to be removable from an adherend. However, in the present invention, "adhesive" and "adhesive" are not necessarily clearly distinguishable, and "adhesive layer" and "adhesive layer" are not necessarily clearly distinguishable. In the present invention, the pressure-sensitive adhesive or adhesive that forms the pressure-sensitive adhesive layer is not particularly limited, and for example, a general pressure-sensitive adhesive or adhesive can be used. Examples of the pressure-sensitive adhesive or adhesive include polymer adhesives such as acrylic, vinyl alcohol, silicone, polyester, polyurethane, and polyether adhesives, and rubber adhesives. Also included are adhesives made of water-soluble crosslinking agents of vinyl alcohol polymers such as glutaraldehyde, melamine, and oxalic acid. Examples of the adhesive include the adhesives described above. These pressure-sensitive adhesives and adhesives may be used alone or in combination (for example, mixed, laminated, etc.). As mentioned above, the adhesive layer can protect the void layer from physical damage (especially scratches). In addition, the adhesive layer preferably has excellent pressure resistance so that the void layer does not collapse even when used as a void layer-containing adhesive sheet without a base material (substrate-less). Not limited. Further, the thickness of the adhesive layer is not particularly limited, but is, for example, 0.1 to 100 μm, 5 to 50 μm, 10 to 30 μm, or 12 to 25 μm.

The void layer of the present invention obtained in this way may be further laminated with another film (layer) to form a laminated structure including the porous structure. In this case, in the laminated structure, each component may be laminated, for example, via the adhesive layer (adhesive or adhesive).

For example, since the lamination of each component is efficient, lamination may be performed by continuous processing using a long film (so-called Roll to Roll, etc.), and when the base material is a molded article, an element, etc. may be laminated after batch processing.

Below, the method for forming the laminate of the present invention on a base material (resin film) will be explained with reference to FIGS. 1 to 3 as an example regarding continuous processing steps. Although FIG. 2 shows the process of laminating and winding up a protective film after forming the void layer (porous silicone material), if laminating it onto another functional film, the above method can be used. Alternatively, after coating and drying another functional film, it is also possible to bond the above-mentioned void layer formed into the film immediately before winding up. Note that the illustrated film forming method is just an example, and the present invention is not limited thereto.

In addition, the resin film mentioned above may be sufficient as the said base material. In this case, the void layer of the present invention can be obtained by forming the void layer on the base material. The void layer of the present invention can also be obtained by forming the void layer on the base material and then laminating the void layer on the resin film described above in the description of the void layer of the present invention.

The cross-sectional view of FIG. 1 shows an example of the steps in the method for manufacturing a laminate of the present invention in which the void layer, the intermediate layer, and the adhesive layer are laminated in the above order on the base material (resin film). Shown schematically. In FIG. 1, the method for forming the void layer is a coating step of coating a sol particle liquid 20'' of the pulverized product of the gel-like compound on a base material (resin film) 10 to form a coating film. (1), a drying step (2) of drying the sol particle liquid 20'' to form a dried coating film 20', and a chemical treatment (for example, crosslinking treatment) on the coating film 20'. A chemical treatment step (for example, crosslinking step) (3) for forming the void layer 20, and an adhesive layer coating step (adhesive layer forming step) for coating the adhesive layer 30 on the void layer 20. (4), and an intermediate layer forming step (5) of reacting the void layer 20 with the adhesive layer 30 to form the intermediate layer 22. Note that the chemical treatment step (crosslinking step) (3) corresponds to the "void layer forming step" in the method for producing a laminated film of the present invention. In addition, in the figure, the intermediate layer forming step (5) (hereinafter sometimes referred to as "aging step") is a step of improving the strength of the void layer 20 (a crosslinking reaction step of causing a crosslinking reaction inside the void layer 20). ), and after the intermediate layer forming step (5), the void layer 20 changes to a void layer 21 with improved strength. However, the present invention is not limited to this, and for example, the void layer 20 does not need to change after the intermediate layer forming step (5). Further, as described above, the adhesive layer forming step is not limited to coating the adhesive layer, but may also include bonding of an adhesive tape having an adhesive layer. Through the above steps (1) to (5), a laminated film is produced in which the void layer 21, the intermediate layer 22, and the adhesive layer 30 are laminated in the above order on the resin film 10, as shown in the figure. can. However, the intermediate layer forming step (5) may be omitted, and the produced laminate of the present invention may not include an intermediate layer. Furthermore, the method for producing a laminated film of the present invention may or may not include steps other than steps (1) to (5) as appropriate.

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

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

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

Further, an adhesive layer coating step (adhesive layer forming step) (4) and an intermediate layer forming step (5) are performed. The adhesive layer coating step (adhesive layer forming step) (4) may include, for example, in addition to the step of applying the adhesive, a heating step of heating the adhesive after coating. good. For example, when the adhesive is an adhesive composition containing a polymer (for example, a (meth)acrylic polymer) and a crosslinking agent, the polymer may be crosslinked by the crosslinking agent in the heating step. For example, the heating step may also serve as a step of drying the adhesive. Further, for example, the heating step may also serve as the intermediate layer forming step (5). The temperature in the heating step is not particularly limited, and is, for example, 70 to 160°C, 80 to 155°C, or 90 to 150°C. The time for the heating step is not particularly limited, and is, for example, 1 to 10 minutes, 1 to 7 minutes, or 2 to 5 minutes.

Next, FIG. 2 schematically shows an example of a slot die coating apparatus and a method of forming the void layer using the same. Note that although FIG. 2 is a cross-sectional view, hatching is omitted for ease of viewing.

As shown in the figure, each step in the method using this device is performed while the base material 10 is conveyed in one direction by rollers. The conveyance speed is not particularly limited, and is, for example, 1 to 100 m/min, 3 to 50 m/min, or 5 to 30 m/min.

First, while the base material 10 is fed out from the feed roller 101 and conveyed, a coating process (1) is performed in which the sol particle liquid 20'' is applied to the base material 10 on the coating roll 102, and then the oven zone In step 110, the process moves to a drying step (2). In the coating apparatus of FIG. 2, a preliminary drying process is performed after the coating process (1) and prior to the drying process (2). The pre-drying step can be performed at room temperature without heating. In the drying step (2), heating means 111 is used. As the heating means 111, as described above, a hot air blower, a heating roll, a far-infrared heater, etc. can be used as appropriate. Further, for example, the drying step (2) may be divided into a plurality of steps, and the drying temperature may be set higher in the later drying steps.

After the drying step (2), a chemical treatment step (3) is performed within the chemical treatment zone 120. In the chemical treatment step (3), for example, when the dried coating film 20' contains a photoactive catalyst, it is irradiated with light using lamps (light irradiation means) 121 disposed above and below the base material 10. Alternatively, for example, when the dried coating film 20' contains a thermally activated catalyst, a hot air blower (heating means) is used instead of the lamp (light irradiation device) 121, and the hot air blowers 121 are placed above and below the base material 10. The base material 10 is heated. This crosslinking treatment causes chemical bonding between the pulverized materials in the coating film 20', thereby hardening and strengthening the void layer 20. In this example, the chemical treatment step (3) is performed after the drying step (2), but as mentioned above, at what stage in the production method of the present invention is the chemical bonding between the pulverized materials caused? is not particularly limited. For example, as described above, the drying step (2) may also serve as the chemical treatment step (3). Further, even if the chemical bonding occurs in the drying step (2), a chemical treatment step (3) may be further performed to further strengthen the chemical bonding between the pulverized materials. Further, in a process before the drying process (2) (for example, a pre-drying process, a coating process (1), a process of preparing a coating liquid (for example, a suspension), etc.), chemical Coupling may occur.

After the chemical treatment step (3), an adhesive or an adhesive is applied (coated) on the void layer 20 by the adhesive layer coating means 131a in the adhesive layer coating zone 130a, and the adhesive is applied. An adhesive layer coating step (adhesive layer forming step) (4) for forming the adhesive layer 30 is performed. Further, as described above, instead of applying (coating) an adhesive or an adhesive, an adhesive tape or the like having an adhesive layer 30 may be pasted (attached).

Furthermore, an intermediate layer forming step (aging step) (5) is performed in the intermediate layer forming zone (aging zone) 130, and the void layer 20 and the adhesive layer 30 are reacted to form the intermediate layer 22. Further, as described above, in this step, a crosslinking reaction occurs inside the void layer 20, and the void layer 21 becomes the void layer 21 with improved strength. The intermediate layer forming step (aging step) (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 base material 10. good. The heating temperature, time, etc. are not particularly limited, and are, for example, as described above.

After the intermediate body forming step (aging step) (5), the laminate in which the void layer 21 is formed on the base material 10 is wound up by a winding roll 105. In addition, in FIG. 2, the void layer 21 of the laminate is covered and protected with a protective sheet fed out from the roll 106. Here, instead of the protective sheet, another layer formed from a long film may be laminated on the void layer 21.

FIG. 3 schematically shows an example of a coating device for the microgravure method (microgravure coating method) and a method for forming the void layer using the same. Although this figure is a cross-sectional view, hatching is omitted for ease of viewing.

As shown in the figure, each step in the method using this device is performed while the base material 10 is conveyed in one direction by rollers, as in FIG. The conveyance speed is not particularly limited, and is, for example, 1 to 100 m/min, 3 to 50 m/min, or 5 to 30 m/min.

First, a coating step (1) is performed in which the sol particle liquid 20'' is applied to the base material 10 while the base material 10 is fed out from the feed roller 201 and conveyed. 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 further, while controlling the thickness to a predetermined value with the doctor 203, the microgravure 204 is applied to the base material 10. Coat on the surface. Note that the microgravure 204 is an example, and the present invention is not limited to this, and any other coating means may be used.

Next, a drying step (2) is performed. Specifically, as shown in the figure, the base material 10 coated with the sol particle liquid 20'' is transported into the oven zone 210, and heated by the heating means 211 in the oven zone 210 to form the sol particle liquid 20''. ' to dry. The heating means 211 may be similar to that shown in FIG. 2, for example. Further, for example, by dividing the oven zone 210 into a plurality of sections, the drying step (2) may be divided into a plurality of steps, and the drying temperature may be set higher in the later drying steps. After the drying step (2), a chemical treatment step (3) is performed in the chemical treatment zone 220. In the chemical treatment step (3), for example, when the dried coating film 20' contains a photoactive catalyst, it is irradiated with light using lamps (light irradiation means) 221 disposed above and below the base material 10. Alternatively, for example, when the dried coating film 20' contains a thermally activated catalyst, a hot air blower (heating means) may be used instead of the lamp (light irradiation device) 221, and hot air blowers ( Heating means) 221 heats the base material 10. Through this crosslinking treatment, chemical bonding occurs between the pulverized materials in the coating film 20', and a void layer 20 is formed.

After the chemical treatment step (3), an adhesive or an adhesive is applied (coated) on the void layer 20 by the adhesive layer coating means 231a in the adhesive layer coating zone 230a to form an adhesive layer. An adhesive layer coating step (adhesive layer forming step) (4) for forming the adhesive layer 30 is performed. Further, as described above, instead of applying (coating) an adhesive or an adhesive, an adhesive tape or the like having an adhesive layer 30 may be pasted (attached).

Furthermore, an intermediate layer forming step (aging step) (5) is performed in the intermediate layer forming zone (aging zone) 230, and the void layer 20 and the adhesive layer 30 are reacted to form the intermediate layer 22. Further, as described above, in this step, the void layer 20 becomes the void layer 21 with improved strength. The intermediate layer forming step (aging step) (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 base material 10. good. The heating temperature, time, etc. are not particularly limited, and are, for example, as described above.

After the intermediate body forming step (aging step) (5), the laminated film in which the void layer 21 is formed on the base material 10 is wound up by a winding roll 251. After that, for example, another layer may be laminated on the laminated film. Further, before the laminated film is wound up by the take-up roll 251, another layer may be laminated on the laminated film, for example.

Next, examples of the present invention will be described. However, the present invention is not limited to the following examples.

In addition, in the following Reference Examples, Examples, and Comparative Examples, the number of parts (relative usage amount) of each substance is in parts by mass (parts by weight) unless otherwise specified.

In addition, in the following reference examples, examples, and comparative examples, the storage modulus of the adhesive layer at 23°C, the gel fraction of the adhesive layer, the thickness of each layer, and the weight average of the sol content of the adhesive layer. The molecular weights were each measured by the following measurement method.

(Measurement method of storage modulus)
Using a viscoelasticity measuring device ARES (trade name of TA Instruments), the storage modulus of the adhesive layer at 23° C. was measured by the following method. That is, first, a sheet (layer) that was the same as the adhesive layer in each of the following Reference Examples, Examples, and Comparative Examples was molded, except that it was in the form of a sheet with a thickness of 2 mm. The sheet was punched out to fit a parallel plate having a diameter of 25 mm, and was used as a measurement sample. This measurement sample was mounted on the chuck of the viscoelasticity measuring device ARES. Then, while applying strain at a cycle of 1 Hz, the temperature was raised from -70° C. to 150° C. at a heating rate of 5° C./min, and the storage modulus at 23° C. was measured.

(Method for measuring gel fraction of adhesive layer)
Measurement samples prepared in the same manner as the adhesive layers in the following Reference Examples, Examples, and Comparative Examples (each adhesive composition was applied and then dried by heating) were prepared. This measurement sample (initial weight W1) was immersed in ethyl acetate, left for one week at room temperature, the insoluble matter was removed, the dried weight (W2) was measured, and the gel fraction was determined based on the following formula (II). was calculated.

Gel fraction (wt%) = (W2/W1) x 100 (II)

In addition, in the adhesive layers in the following Reference Examples, Examples, and Comparative Examples, the polymer (acrylic polymer) was crosslinked with a crosslinking agent by heating and drying the applied adhesive, and a crosslinked structure was formed. Although it is speculated, the crosslinked structure has not been confirmed.

(Measurement method of thickness)
Measured using a dial gauge.

(Method for measuring weight average molecular weight of sol component in adhesive layer)
The weight average molecular weight of the sol component and the proportion (weight percentage) of low molecular weight components with a molecular weight of 10,000 or less were calculated from the molecular weight weight distribution curve measured by gel permeation chromatography (GPC). Specifically, first, measurement samples (each adhesive composition was applied and then dried by heating) were prepared in the same manner as the adhesive layers in the following Reference Examples, Examples, and Comparative Examples. A mixture of 200 mg of this measurement sample and 10 ml of tetrahydrofuran (THF) was left to stand for 20 hours, and filtered through a 0.45 μm membrane filter. Thereafter, the obtained filtrate was subjected to GPC measurement using the following measuring device and measurement conditions, and as mentioned above, from the molecular weight weight distribution curve, the weight average molecular weight of the sol component and the ratio of low molecular weight components with a molecular weight of 10,000 or less ( Weight percentage) was calculated.

GPC measurement device: Product name “AQCUITY APC” (manufactured by Water)
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°C
Injection volume: 100μL
Standard: polystyrene

[Reference Example 1: Production of coating liquid for forming void layer]
First, gelation of a silicon compound (step (1) below) and aging step (step (2) below) were performed to produce a gel (porous silicone material) having a porous structure. Further thereafter, the following (3) morphology control step, (4) solvent replacement step, and (5) gel crushing step were performed to obtain a coating liquid for forming a void layer (liquid containing crushed gel material). In addition, in this reference example, the following (3) form control step was performed as a separate step from the following step (1) as described below. However, the present invention is not limited thereto, and for example, the following (3) form control step may be performed during the following step (1).

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

After adding 3.8 kg of 28% aqueous ammonia and 2 kg of pure water to 55 kg of DMSO, the hydrolyzed mixture was further added and stirred at room temperature for 60 minutes. After stirring for 60 minutes, the solution was poured into a stainless steel container measuring 30 cm long x 30 cm wide x 5 cm high, and allowed to stand at room temperature to gel the tris(hydroxy)methylsilane and obtain a gelled silicon compound. Ta.

(2) Aging process The gel-like silicon compound obtained by performing the gelling treatment was incubated at 40° C. for 20 hours to perform an aging treatment to obtain the gel in the rectangular parallelepiped-shaped mass. Since the amount of DMSO (high boiling point solvent with a boiling point of 130°C or higher) used in the raw material was approximately 83% by weight of the total raw material, this gel contained 50% by weight or more of a high boiling point solvent with a boiling point of 130°C or higher. It was clear that In addition, since the amount of MTMS (monomer that is the constituent unit of gel) used in the raw material was approximately 8% by weight of the entire raw material, hydrolysis of the monomer (MTMS) that is the constituent unit of gel It was clear that the content of the solvent (methanol in this case) with a boiling point of less than 130° C. generated was 20% by weight or less.

(3) Form control step Water, which is a replacement solvent, was poured onto the gel synthesized in the 30 cm x 30 cm x 5 cm stainless steel container in 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 to cut the gel into a rectangular parallelepiped with a size of 1.5 cm x 2 cm x 5 cm.

(4) Solvent replacement step Next, a solvent replacement step was performed as described in (4-1) to (4-3) below.

(4-1) After the "(3) Form control step", the gel silicon compound was immersed in water weighing 8 times as much as the gel silicon compound, and slowly stirred for 1 hour so that only water was convected. After 1 h, the water was replaced with the same amount of water, and the mixture was further stirred for 3 h. After that, the water was exchanged again, and then the mixture was heated at 60° C. for 3 hours with slow stirring.

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

(4-3) After (4-2), isopropyl alcohol was replaced with the same weight of isobutyl alcohol and heated at 60° C. for 6 hours to replace the solvent contained in the gelled silicon compound with isobutyl alcohol. In the manner described above, the gel for producing a void layer of the present invention was produced.

(5) Gel pulverization step The gel (gelled silicon compound) after the solvent replacement step (4) is subjected to a continuous emulsification dispersion (manufactured by Taiheiyo Kiko Co., Ltd., Milder MDN304 type) and a second pulverization step. In the pulverization stage, pulverization was carried out in two stages of high-pressure medialess pulverization (manufactured by Sugino Machine Co., Ltd., Starburst HJP-25005 model). This pulverization process involves adding and weighing 26.6 kg of isobutyl alcohol to 43.4 kg of gel containing the solvent-substituted gel silicon compound as a solvent. In the second pulverization step, pulverization was performed at a pulverization pressure of 100 MPa. In this way, an isobutyl alcohol dispersion (liquid containing the pulverized gel) in which nanometer-sized particles (the pulverized gel) were dispersed was obtained. Furthermore, 224 g of a 1.5% concentration solution of WPBG-266 (trade name, manufactured by Wako) in methyl isobutyl ketone was added to 3 kg of the liquid containing the gel pulverized material, and methyl After adding 67.2 g of a 5% concentration solution of isobutyl ketone, 31.8 g of N,N-dimethylformamide was added and mixed to obtain a coating liquid.

In the manner described above, a coating liquid for forming a void layer (liquid containing pulverized gel material) of this reference example (reference example 1) was produced. Further, the peak pore diameter of the gel pulverized material (microporous particles) in the void layer forming coating solution (gel pulverized material-containing solution) was measured by the method described above, and was found to be 12 nm.

[Reference Example 2: Formation of adhesive layer]
The adhesive layer of this reference example (reference example 2) was formed by the following steps (1) to (3).

(1) Preparation of acrylic polymer solution In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas introduction tube, and condenser, 90.7 parts of butyl acrylate, 6 parts of N-acryloylmorpholine, and 3 parts of acrylic acid were placed. , 0.3 part of 2-hydroxybutyl acrylate, and 0.1 part by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator were added together with 100 g of ethyl acetate. Next, nitrogen gas was introduced into the contents of the four-necked flask while gently stirring the contents to replace the contents with nitrogen. Thereafter, the temperature of the liquid in the four-necked flask was maintained at around 55° C., and a polymerization reaction was carried out for 8 hours to prepare an acrylic polymer solution.

(2) Preparation of acrylic adhesive composition For 100 parts of the solid content of the acrylic polymer solution obtained in the above (1), an isocyanate crosslinking agent (trade name "Coronate L" manufactured by Nippon Polyurethane Industries, Ltd., Adduct of tolylene diisocyanate of methylolpropane) 0.2 parts, benzoyl peroxide (trade name "Niper BMT" manufactured by NOF Corporation) 0.3 parts, γ-glycidoxypropylmethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) An acrylic adhesive composition (acrylic adhesive solution) containing 0.2 part of the product (trade name "KBM-403") was prepared.

(3) Formation of adhesive layer The acrylic adhesive composition obtained in (2) above was applied to a silicone-treated polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm). It was coated on one side so that the thickness of the adhesive layer after drying was 12 μm, and was dried at 150° C. for 3 minutes to form an adhesive layer (adhesive layer). The storage modulus G' of this adhesive layer (adhesive layer) at 23° C. was 1.3×10 ⁵ .

[Reference Example 3: Formation of adhesive layer]
The adhesive layer of this reference example (reference example 3) was formed by the following steps (1) to (3).

(1) Preparation of acrylic polymer solution In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser, 96.9 parts of butyl acrylate, 3 parts of acrylic acid, and 0.0 parts of 2-hydroxyethyl acrylate were placed. and 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator were added together with 100 g of ethyl acetate. Next, nitrogen gas was introduced into the contents of the four-necked flask while gently stirring the contents to replace the contents with nitrogen. Thereafter, the temperature of the liquid in the four-necked flask was maintained at around 55° C., and a polymerization reaction was carried out for 8 hours to prepare an acrylic polymer solution.

(2) Preparation of acrylic adhesive composition For 100 parts of the solid content of the acrylic polymer solution obtained in the above (1), an isocyanate crosslinking agent (trade name "Coronate L" manufactured by Nippon Polyurethane Industries, Ltd., 0.5 parts of tolylene diisocyanate adduct of methylolpropane), 0.2 parts of benzoyl peroxide (trade name "Nyper BMT" manufactured by NOF Corporation), and γ-glycidoxypropylmethoxysilane (Shin-Etsu Chemical Co., Ltd.) A solution of an acrylic pressure-sensitive adhesive composition was prepared by adding 0.2 part of acrylic pressure-sensitive adhesive composition (trade name: "KBM-403" manufactured by Co., Ltd.).

(3) Formation of adhesive layer A solution of the acrylic adhesive composition obtained in (2) above was applied to a silicone-treated polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm). ) was applied so that the thickness of the adhesive layer after drying was 20 μm, and dried at 150° C. for 3 minutes to form an adhesive layer (adhesive layer). The storage modulus G' of this adhesive layer (adhesive layer) at 23° C. was 1.1×10 ⁵ .

[Reference Example 4: Formation of adhesive layer]
The adhesive layer of this reference example (reference example 4) was formed by the following steps (1) to (3).

(1) Preparation of acrylic polymer solution In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas introduction tube, and condenser, 77 parts of butyl acrylate, 20 parts of phenoxyethyl acrylate, and N-vinyl-2-pyrrolidone were placed. 2 parts of acrylic acid, 0.5 part of 4-hydroxybutyl acrylate, and 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator were added together with 100 parts of ethyl acetate. Next, nitrogen gas was introduced into the contents of the four-necked flask while gently stirring the contents to replace the contents with nitrogen. Thereafter, the temperature of the liquid in the four-necked flask was maintained at around 55° C., and a polymerization reaction was carried out for 8 hours to prepare an acrylic polymer solution.

(2) Preparation of acrylic adhesive composition For 100 parts of the solid content of the acrylic polymer solution obtained in (1) above, an isocyanate crosslinking agent (trade name "Takenate D160N" manufactured by Mitsui Chemicals, Inc., Methylolpropane hexamethylene diisocyanate) 0.1 part, benzoyl peroxide (trade name "Niper BMT" manufactured by NOF Corporation) 0.3 parts, γ-glycidoxypropylmethoxysilane (trade name "Niper BMT" manufactured by Shin-Etsu Chemical Co., Ltd.), 0.3 parts A solution of an acrylic pressure-sensitive adhesive composition was prepared by blending 0.2 part of ``KBM-403'').

(3) Formation of adhesive layer The solution of the acrylic adhesive composition obtained in (2) above was applied to a polyethylene terephthalate film treated with a silicone release agent (separator film: manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.). It was coated on one side of a film (trade name "MRF38") and dried at 150° C. for 3 minutes to form an adhesive layer (adhesive layer) with a thickness of 20 μm on the surface of the separator film. The storage modulus G' of this adhesive layer (adhesive layer) at 23° C. was 1.1×10 ⁵ .

[Reference Example 5: Formation of adhesive layer]
The adhesive layer of this reference example (reference example 5) was formed by the following steps (1) to (3).

(1) Preparation of prepolymer composition A monomer mixture composed of 68 parts of 2-ethylhexyl acrylate, 14.5 parts of N-vinyl-2-pyrrolidone, and 17.5 parts of 2-hydroxyethyl acrylate was photopolymerized. After blending 0.035 parts of an initiator (trade name "Irgacure 184", BASF Corporation) and 0.035 parts of a photopolymerization initiator (trade name "Irgacure 651", BASF Corporation), the viscosity (BH viscometer No. 5 Ultraviolet rays were irradiated until the rotor (10 rpm, measurement temperature 30° C.) reached about 20 Pa·s to obtain a prepolymer composition in which a portion of the monomer components were polymerized.

(2) Preparation of acrylic adhesive composition Add 0.150 parts of hexanediol diacrylate (HDDA), a silane coupling agent (trade name "KBM-403") to the prepolymer composition obtained in (1) above, (Shin-Etsu Chemical Co., Ltd.) was added and mixed to obtain an acrylic pressure-sensitive adhesive composition.

(3) Formation of adhesive layer The acrylic adhesive composition obtained in (2) above was applied to a silicone-treated polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 50 μm). A polyethylene terephthalate (PET) film (manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., thickness: 38 μm) was coated on one side so that the adhesive layer had a thickness of 25 μm after drying, and the coated layer was further treated with silicone. was applied to cover the coating layer and block oxygen. Next, this laminate was irradiated with ultraviolet rays at an illumination intensity of 5 mW/cm 2 for 300 seconds using a black light (manufactured by Toshiba) from the top surface (MRF 38 side) of the laminate. Further, a drying process was performed for 2 minutes in a dryer at 90° C. to volatilize the remaining monomer and form an adhesive layer (adhesive layer). The storage modulus G' of this adhesive layer (adhesive layer) at 23° C. was 1.1×10 ⁵ .

[Reference Example 6: Formation of adhesive layer]
The adhesive layer of this reference example (reference example 6) was formed by the following steps (1) to (3).

(1) Preparation of acrylic polymer solution 99 parts of butyl acrylate, 1 part of 4-hydroxybutyl acrylate, and a polymerization initiator were placed in a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser. 0.1 part of 2,2'-azobisisobutyronitrile was added together with 100 parts of ethyl acetate. Next, nitrogen gas was introduced into the contents of the four-necked flask while gently stirring the contents to replace the contents with nitrogen. Thereafter, the temperature of the liquid in the four-necked flask was maintained at around 55° C., and a polymerization reaction was carried out for 8 hours to prepare an acrylic polymer solution.

(2) Preparation of acrylic adhesive composition For 100 parts of the solid content of the acrylic polymer solution obtained in the above (1), add an isocyanate crosslinking agent (trade name "Takenate D110N" manufactured by Mitsui Takeda Chemical Co., Ltd.), Methylolpropane xylylene diisocyanate) 0.1 part, benzoyl peroxide (trade name "Niper BMT" manufactured by NOF Corporation) 0.1 part, γ-glycidoxypropylmethoxysilane (trade name "Niper BMT" manufactured by Shin-Etsu Chemical Co., Ltd.), 0.1 part A solution of an acrylic pressure-sensitive adhesive composition was prepared by blending 0.2 part of ``KBM-403'').

(3) Formation of adhesive layer The solution of the acrylic adhesive composition obtained in (2) above was applied to a polyethylene terephthalate film treated with a silicone release agent (separator film: manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.). It was coated on one side of a film (trade name "MRF38") and dried at 150° C. for 3 minutes to form an adhesive layer (adhesive layer) with a thickness of 20 μm on the surface of the separator film. The storage modulus G' of this adhesive layer (adhesive layer) at 23° C. was 8.2×10 ⁴ .

[Reference Example 7: Formation of Adhesive Layer] The adhesive layer of this Reference Example (Reference Example 7) was formed by the following procedures (1) to (3).

(1) Preparation of acrylic polymer solution In a four-necked flask equipped with a stirring blade, thermometer, nitrogen gas introduction tube, and condenser, 90.7 parts of butyl acrylate, 6 parts of N-acryloylmorpholine, and 3 parts of acrylic acid were placed. , 0.3 part of 2-hydroxybutyl acrylate, and 0.1 part by weight of 2,2'-azobisisobutyronitrile as a polymerization initiator were added together with 100 g of ethyl acetate. Next, nitrogen gas was introduced into the contents of the four-necked flask while gently stirring the contents to replace the contents with nitrogen. Thereafter, the temperature of the liquid in the four-necked flask was maintained at around 55° C., and a polymerization reaction was carried out for 8 hours to prepare an acrylic polymer solution.

(2) Preparation of acrylic adhesive composition For 100 parts of the solid content of the acrylic polymer solution obtained in the above (1), an isocyanate crosslinking agent (trade name "Coronate L" manufactured by Nippon Polyurethane Industries, Ltd., Adduct of tolylene diisocyanate of methylolpropane) 0.15 parts, benzoyl peroxide (trade name "Nyper BMT" manufactured by NOF Corporation) 0.2 parts, γ-glycidoxypropylmethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd.) An acrylic adhesive composition (acrylic adhesive solution) containing 0.2 part of the product (trade name "KBM-403") was prepared.

(3) Formation of adhesive layer The solution of the acrylic adhesive composition obtained in (2) above was applied to a polyethylene terephthalate film treated with a silicone release agent (separator film: manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.). It was coated on one side of a film (trade name "MRF38") and dried at 150° C. for 3 minutes to form an adhesive layer (adhesive layer) with a thickness of 75 μm on the surface of the separator film. The storage modulus G' of this adhesive layer (adhesive layer) at 23° C. was 1.0×10 ⁵ .

[Reference Example 8: Formation of Adhesive Layer] The adhesive layer of this Reference Example (Reference Example 8) was formed by the following procedures (1) to (3).

(1) Preparation of acrylic polymer solution In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser, 95 parts of butyl acrylate, 5 parts of acrylic acid, and 2. 0.1 part of 2'-azobisisobutyronitrile was added together with 100 g of ethyl acetate. Next, nitrogen gas was introduced into the contents of the four-necked flask while gently stirring the contents to replace the contents with nitrogen. Thereafter, the temperature of the liquid in the four-necked flask was maintained at around 55°C to carry out a polymerization reaction for 8 hours, and then the temperature of the liquid in the flask was raised to 70°C and the reaction was carried out for 2 hours to prepare an acrylic polymer solution. did.

(2) Preparation of acrylic adhesive composition For 100 parts of the solid content of the acrylic polymer solution obtained in the above (1), an isocyanate crosslinking agent (trade name "Coronate L" manufactured by Nippon Polyurethane Industries, Ltd., 0.7 parts of methylolpropane tolylene diisocyanate adduct), 0.2 parts of benzoyl peroxide (trade name "Nyper BMT" manufactured by NOF Corporation), and γ-glycidoxypropylmethoxysilane (Shin-Etsu Chemical Co., Ltd.) A solution of an acrylic pressure-sensitive adhesive composition was prepared by adding 0.2 part of acrylic pressure-sensitive adhesive composition (trade name: "KBM-403" manufactured by Co., Ltd.).

(3) Formation of adhesive layer The solution of the acrylic adhesive composition obtained in (2) above was applied to a polyethylene terephthalate film treated with a silicone release agent (separator film: manufactured by Mitsubishi Chemical Polyester Film Co., Ltd.). It was coated on one side of a film (trade name "MRF38") and dried at 150° C. for 3 minutes to form an adhesive layer (adhesive layer) with a thickness of 75 μm on the surface of the separator film. The storage modulus G' of this adhesive layer (adhesive layer) at 23° C. was 7.7×10 ⁴ .

[Example 1]
The high porosity layer forming coating liquid prepared in Reference Example 1 was applied onto an acrylic base material and dried to form a porosity layer with a thickness of about 850 nm (porosity 59% by volume). Next, UV irradiation (300 mJ) was performed from the surface of the void layer. Thereafter, the adhesive having a thickness of 12 μm obtained in Reference Example 2 was laminated onto the surface of the void layer, and aging was performed at 60° C. for 20 hours to produce a laminate of this example.

Further, the laminate of this example produced as described above was placed in an oven at 85° C. and 85% RH, and a heating and humidification durability test was conducted for 500 hours. The degree of filling of the voids in the void layer after the heating and humidification durability test was confirmed by SEM, and the residual percentage of voids was calculated. The results are shown in Table 1.

[Example 2]
A laminate of this example was produced in the same manner as in Example 1, except that the adhesive obtained in Reference Example 3 was used instead of the adhesive of Reference Example 2. Furthermore, a heating and humidification durability test was conducted in the same manner as in Example 1, and the residual percentage of porosity was calculated. The results are shown in Table 1.

[Example 3]
A laminate of this example was produced in the same manner as in Example 1, except that the adhesive obtained in Reference Example 4 was used instead of the adhesive of Reference Example 2. Furthermore, a heating and humidification durability test was conducted in the same manner as in Example 1, and the residual percentage of porosity was calculated. The results are shown in Table 1.

[Example 4]
A laminate of this example was produced in the same manner as in Example 1, except that the adhesive obtained in Reference Example 5 was used instead of the adhesive of Reference Example 2. Furthermore, a heating and humidification durability test was conducted in the same manner as in Example 1, and the residual percentage of porosity was calculated. The results are shown in Table 1.

[Example 5]
A laminate of this example was produced in the same manner as in Example 1, except that the thickness of the adhesive layer formed using the adhesive of Reference Example 2 was 5 μm. Furthermore, a heating and humidification durability test was conducted in the same manner as in Example 1, and the residual percentage of porosity was calculated. The results are shown in Table 1.

[Example 6]
A laminate of this example was produced in the same manner as in Example 1, except that the adhesive obtained in Reference Example 7 was used instead of the adhesive of Reference Example 2. Furthermore, a heating and humidification durability test was conducted in the same manner as in Example 1, and the residual percentage of porosity was calculated. The results are shown in Table 1.

[Comparative example 1]
A laminate of this comparative example was produced in the same manner as in Example 1, except that the adhesive obtained in Reference Example 6 was used instead of the adhesive of Reference Example 2. Furthermore, a heating and humidification durability test was conducted in the same manner as in Example 1, and the residual percentage of porosity was calculated. The results are shown in Table 1.

[Comparative example 2]
A laminate of this comparative example was produced in the same manner as in Example 1, except that an epoxy adhesive semi-cured by UV (ultraviolet irradiation) was used instead of the adhesive of Reference Example 2. Furthermore, a heating and humidification durability test was conducted in the same manner as in Example 1, and the residual percentage of porosity was calculated. The results are shown in Table 1.

[Comparative example 3]
A laminate of this comparative example was produced in the same manner as in Example 1, except that the adhesive obtained in Reference Example 8 was used instead of the adhesive of Reference Example 2. Furthermore, a heating and humidification durability test was conducted in the same manner as in Example 1, and the residual percentage of porosity was calculated. The results are shown in Table 1.

Further, the adhesive strength of each of the laminates of Examples 1 to 6 and Comparative Examples 1 to 3 was measured by the above-mentioned measuring method. In addition, the storage modulus of the adhesive layer at 23°C, the gel fraction of the adhesive layer, the thickness of the intermediate layer, the thickness of the adhesive layer, and the weight average molecular weight of the sol component of the adhesive layer, respectively. The measurement was performed using the measurement method described above. Furthermore, the void locations were binarized from the SEM image of the laminate after the durability test, and the void remaining ratio was calculated. The results are also shown in Table 1.

As shown in Table 1, the laminates of Examples 1 to 6 were able to achieve both high adhesive strength and difficulty in penetrating the adhesive (adhesive layer) into the voids. On the other hand, in the laminates of Comparative Examples 1 to 3, the adhesive (adhesive layer) penetrated into the voids in the void layer, and the percentage of voids remaining in the void layer after the durability test was low.

As explained above, according to the present invention, a laminate of a void layer and an adhesive layer, an optical A member and an optical device can be provided. The use of the present invention is not particularly limited. For example, the optical device of the present invention is not particularly limited, and examples include an image display device, a lighting device, and the like. Examples of the image display device include a liquid crystal display, an organic EL display, a micro LED display, and the like. Examples of the lighting device include organic EL lighting. Further, the use of the laminate of the present invention is not limited to the optical member and optical device of the present invention, but is arbitrary, and can be used for a wide range of purposes.

10 base material 20 void layer 20' coating film (after drying)
20'' Sol particle liquid 21 Gap layer with improved strength 22 Intermediate layer 30 Adhesive layer 101 Delivery roller 102 Coating roll 110 Oven zone 111 Hot air generator (heating means)
120 Chemical treatment 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 blower (heating means)
105 Take-up roll 106 Roll 201 Delivery roller 202 Liquid reservoir 203 Doctor (doctor knife)
204 Microgravure 210 Oven zone 211 Heating means 220 Chemical treatment zone 221 Light irradiation means or heating means 230a Adhesive layer coating zone 230 Intermediate formation zone 231a Adhesive layer coating means 231 Hot air blower (heating means)
251 Take-up roll

Claims (19)

including a void layer and an adhesive layer,
The adhesive layer is directly laminated on one or both sides of the void layer,
The porosity of the void layer is 35% by volume or more,
A laminate characterized in that, after a heating and humidifying durability test held at a temperature of 85° C. and a relative humidity of 85% for 500 hours, the void remaining rate of the void layer is 50% by volume or more of that before the heating and humidifying durability test. 2. The void remaining ratio of the void layer after the heating and humidifying durability test is more than 50% and not more than 99% of the void remaining ratio when only the void layer is subjected to the heating and humidifying durability test. laminate. The void layer and the adhesive layer are laminated with an intermediate layer interposed therebetween,
The intermediate layer is a layer formed by combining a part of the void layer and a part of the adhesive layer,
The thickness of the intermediate layer is 200 nm or less,
The laminate according to claim 1 or 2, wherein the rate of increase in the thickness of the intermediate layer after the heating and humidifying durability test is 500% or less with respect to the thickness of the intermediate layer before the heating and humidifying durability test. including a void layer and an adhesive layer,
The adhesive layer is directly laminated on one or both sides of the void layer,
The porosity of the void layer is 35% by volume or more,
The adhesive layer is formed of an adhesive containing a (meth)acrylic polymer and a crosslinking agent,
The gel fraction of the adhesive layer is 70% or more,
The thickness of the adhesive layer is 2 to 50 μm,
A laminate characterized in that the adhesive layer satisfies the following formula (I).

[(100-X)/100]×Y≦10 (I)

In the formula (I),
X is the gel fraction (%) of the adhesive layer,
Y is the thickness (μm) of the adhesive layer. In measuring the molecular weight of the adhesive layer by gel permeation chromatography method,
The weight average molecular weight of the sol component of the adhesive layer is 50,000 to 500,000,
5. The laminate according to claim 4, wherein the content of low molecular weight components having a molecular weight of 10,000 or less in the sol portion of the adhesive layer is 20% by weight or less. The laminate according to claim 4 or 5, wherein after a heating and humidifying durability test held at a temperature of 85° C. and a relative humidity of 85% for 500 hours, the void remaining rate of the void layer is 50% by volume or more than before the heating and humidifying durability test. body. The void layer and the adhesive layer are laminated with an intermediate layer interposed therebetween,
The intermediate layer is a layer formed by combining a part of the void layer and a part of the adhesive layer,
The laminate according to any one of claims 4 to 6, wherein the intermediate layer has a thickness of 200 nm or less. Claim: After a heating and humidifying durability test held at a temperature of 85° C. and a relative humidity of 85% for 500 hours, the rate of increase in the thickness of the intermediate layer is 500% or less with respect to the thickness of the intermediate layer before the heating and humidifying durability test. 8. The laminate according to any one of 4 to 7. The laminate according to any one of claims 4 to 8, wherein in the adhesive layer, the (meth)acrylic polymer is crosslinked with the crosslinking agent to form a crosslinked structure. including a void layer and an adhesive layer,
The adhesive layer is directly laminated on one or both sides of the void layer,
The porosity of the void layer is 35% by volume or more,
The adhesive layer is formed of an adhesive containing a (meth)acrylic polymer and a crosslinking agent,
The (meth)acrylic polymer contains, as monomer components, 3 to 10% by weight of a heterocycle-containing acrylic monomer, 0.5 to 5% by weight of (meth)acrylic acid, and 0.05 to 2% by weight of hydroxyalkyl (meth)acrylate. , and 83 to 96.45% by weight of alkyl (meth)acrylate, and a (meth)acrylic polymer having a weight average molecular weight of 1.5 million to 2.8 million. 11. The laminate according to claim 10, wherein after a heating and humidifying durability test held at a temperature of 85° C. and a relative humidity of 85% for 500 hours, the void remaining rate of the void layer is 50% by volume or more of that before the heating and humidifying durability test. The void layer and the adhesive layer are laminated with an intermediate layer interposed therebetween,
The intermediate layer is a layer formed by combining a part of the void layer and a part of the adhesive layer,
The laminate according to claim 10 or 11, wherein the intermediate layer has a thickness of 200 nm or less. Claim: After a heating and humidifying durability test held at a temperature of 85° C. and a relative humidity of 85% for 500 hours, the rate of increase in the thickness of the intermediate layer is 500% or less with respect to the thickness of the intermediate layer before the heating and humidifying durability test. 13. The laminate according to any one of 10 to 12. The laminate according to any one of claims 10 to 13, wherein the (meth)acrylic polymer is crosslinked with the crosslinking agent to form a crosslinked structure in the adhesive layer. The laminate according to any one of claims 1 to 14, wherein the void layer has a refractive index of 1.25 or less. 16. The laminate according to claim 1, wherein the adhesive layer is formed of an optical acrylic adhesive having a total light transmittance of 85% or more and a haze of 3% or less. The laminate according to any one of claims 1 to 16, wherein the adhesive layer has a storage modulus of 1.0 x ¹⁰⁵ or more at 23°C. An optical member comprising the laminate according to any one of claims 1 to 16. An optical device comprising the optical member according to claim 18.

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