JP2022123163A - Gel production method and gel production device - Google Patents

Abstract

To provide a technique that can form a raw material liquid layer, which is thinner than the equilibrium thickness, on a high-density base liquid layer, and can also form even a gel layer thinner than the equilibrium thickness.SOLUTION: Provided is a gel production method in which: a raw material liquid of gel is supplied onto a liquid surface of a base liquid layer, the outer periphery of which is surrounded by a molding frame, the base liquid layer having density higher than the raw material liquid; a raw material liquid layer is formed, which comes into contact with the entire inner periphery of the molding frame; after the raw material liquid layer comes into contact with the entire inner periphery of the molding frame, the raw material liquid is discharged out of the molding frame from the raw material liquid layer; the raw material liquid layer is thinned to a thickness below the equilibrium thickness; and the thinned raw material liquid layer is gelated on the liquid surface of the base liquid layer.SELECTED DRAWING: Figure 1B

Description

TECHNICAL FIELD The present disclosure relates to a gel manufacturing method and a gel manufacturing apparatus.

Patent Literature 1 discloses a method for producing a gel. According to this method, the second liquid containing the gel raw material is placed on the first liquid layer containing the first liquid in the container comprising the bottom plate and the side plates extending upward from the periphery of the bottom plate. The second liquid layer is gelled in the presence of the second liquid layer consisting of

WO2019/044669

When the raw material liquid of the gel is supplied onto the base liquid layer B which has a higher density than the raw material liquid, the raw material liquid layer A is formed on the base liquid layer B. If the base liquid layer B is sufficiently wider than the source liquid layer A, the thickness of the source liquid layer A naturally tends to be constant. The thickness is also called the equilibrium thickness. The equilibrium thickness H _A0 is obtained from the following formula (1).

平衡厚みＨ_Ａ０（ｍ）は、上記式（１）に示すように、原料液層Ａの密度ρ_Ａ（ｋｇ／ｍ^３）と、ベース液層Ｂの密度ρ_Ｂ（ｋｇ／ｍ^３）と、原料液層Ａの表面張力σ_Ａ（Ｎ／ｍ）と、ベース液層Ｂの表面張力σ_Ｂ（Ｎ／ｍ）と、原料液層Ａとベース液層Ｂとの界面張力σ_Ａ-Ｂ（Ｎ／ｍ）とから求められる。なお、上記式（１）において「ｇ」は、重力加速度であり、９．８（ｍ／ｓ^２）である。

The equilibrium thickness H _A0 (m) is the density ρ A (kg/m ³ ) of the raw liquid layer A and the density ρ _B (kg/m ³ ) of the base liquid layer _B , as shown in the above formula (1). , the surface tension σ _A (N/m) of the raw liquid layer A, the surface tension σ _B (N/m) of the base liquid layer B, and the interfacial tension σ _{A−B between the raw liquid layer A and the base liquid layer B} (N/m). In addition, "g" in the above formula (1) is the gravitational acceleration, which is 9.8 (m/s ² ).

The equilibrium thickness H _A0 is determined by the combination of the source liquid, which is the material of the source liquid layer A, and the base liquid, which is the material of the base liquid layer B.

One aspect of the present disclosure provides a technique capable of forming a raw material liquid layer thinner than the equilibrium thickness on top of a high-density base liquid layer, thereby forming a gel layer thinner than the equilibrium thickness.

[1] A method for producing a gel according to an aspect of the present disclosure, in which a raw material liquid for a gel is supplied onto a liquid surface surrounded by a mold for a base liquid layer having a higher density than the raw material liquid. Forming a raw material liquid layer in contact with the entire inner circumference of the frame, discharging the raw material liquid from the raw material liquid layer after contacting the entire inner circumference of the mold to the outside of the mold, and making the raw material liquid layer less than the equilibrium thickness and the thinned raw material liquid layer is gelled on the liquid surface of the base liquid layer.

[2] The method described in [1] above, wherein the suction port of the nozzle is installed at the same height as the upper surface of the raw material liquid layer after thinning, and the raw material liquid is removed from the raw material liquid layer to the outside of the mold. discharge to

[3] The method described in [1] or [2] above, wherein the base liquid layer is a liquid compound containing fluorine atoms.

[4] The method according to any one of [1] to [3] above, wherein a gel layer obtained by gelling the raw material liquid layer is lifted from the base liquid layer.

[5] The method according to [4] above, wherein before forming the source liquid layer on the liquid surface of the base liquid layer, the A support plate is installed to support the gel layer from below when the gel layer is lifted from the base liquid layer.

[6] The method according to any one of [1] to [5] above, wherein the solvent contained in the gel layer obtained by gelling the raw material liquid layer is replaced with another solvent. .

[7] The method according to any one of [1] to [6] above, wherein the solvent contained in the gel layer obtained by gelling the raw material liquid layer is removed.

[8] A gel manufacturing apparatus according to an aspect of the present disclosure includes: a mold surrounding the outer periphery of the liquid surface of a base liquid layer having a density higher than that of the raw material liquid of the gel; a raw material liquid supply unit that supplies the raw material liquid to the mold to form a raw material liquid layer in contact with the entire inner circumference of the mold; a raw material suction part that discharges out of the frame and thins the raw material liquid layer to a thickness less than the equilibrium thickness; and a gel that gels the thinned raw material liquid layer on the liquid surface of the base liquid layer. and a gasification promoting part.

[9] The apparatus according to [8] above, wherein the raw material liquid suction unit is positioned at the same height as the upper surface of the thinned raw material liquid layer, and the raw material liquid is drawn from the raw material liquid layer. Includes nozzles that discharge outside the formwork.

[10] The apparatus according to [8] or [9] above, wherein a gel layer obtained by gelling the raw material liquid layer is provided below the interface between the base liquid layer and the raw material liquid layer. It has a support plate that supports the gel layer from below when lifted from the liquid layer.

[11] In the device described in [10] above, the support plate has a plurality of through holes passing through the front and back surfaces of the support plate at intervals in the main surface direction of the support plate.

According to one aspect of the present disclosure, a raw material liquid layer thinner than the equilibrium thickness can be formed on the high-density base liquid layer, and thus a gel layer thinner than the equilibrium thickness can be formed.

FIG. 1A is a cross-sectional view showing a gel manufacturing apparatus according to one embodiment, and is a cross-sectional view showing a state before thinning of a raw material liquid layer. FIG. 1B is a cross-sectional view showing a state after thinning of the raw material liquid layer shown in FIG. 1A. FIG. 2 is a cross-sectional view of the mold along line II-II of FIG. 1A. FIG. 3A is a cross-sectional view showing an example of force balance when the raw material liquid layer is separated from the entire inner periphery of the mold. FIG. 3B is a cross-sectional view showing an example of the force balance when the raw material liquid layer is in contact with the entire inner periphery of the mold, and is a cross-sectional view showing the state before thinning of the raw material liquid layer. FIG. 3C is a cross-sectional view showing a state after the thinning of the raw material liquid layer shown in FIG. 3B. FIG. 3D is a cross-sectional view showing an example of unevenness formed on the side surface of the mold. FIG. 4A is a cross-sectional view showing an example of the base liquid supply unit and the recovery unit, and is a cross-sectional view showing a state before the liquid level of the base liquid layer rises. FIG. 4B is a cross-sectional view showing the state of the base liquid layer shown in FIG. 4A after the liquid level rises. FIG. 5 is a flow chart showing a method for producing a gel according to one embodiment. FIG. 6 is a cross-sectional view showing an example of removing the gel from the mold. FIG. 7 is a cross-sectional view showing another example of removing the gel from the mold.

First, terms used in the present specification and claims will be explained. "Gel" includes both "wet gel" and "xerogel".

A "wet gel" means a gel in which the three-dimensional network is swollen with a swelling agent. It includes hydrogels in which the swelling agent is water, alcogels in which the swelling agent is alcohol, and organogels in which the swelling agent is an organic solvent.

The term "xerogel" is defined in the "Sols, Gels, Networks, and Structures and Processes of Inorganic-Organic Composites" of the "International Union of Pure and Applied Chemistry (IUPAC) Inorganic Chemistry Committee and Polymer Terminology Subcommittee". Definition (IUPAC Recommendation 2007)” means “a gel consisting of an open network formed by removing the swelling agent from the gel”. There are also classification methods such as aerogels that have had the swelling agent removed by supercritical drying, xerogels that have had the swelling agent removed by normal evaporative drying, and cryogel that have had the swelling agent removed by freeze drying. In the claims, these are collectively referred to as xerogels.

"Surface tension" is the force that acts on the interface of a liquid or solid with a gas (eg, air).

"~" indicating a numerical range means that the numerical values before and after it are included as lower and upper limits.

The X-axis direction, Y-axis direction and Z-axis direction are directions perpendicular to each other. The X-axis direction and Y-axis direction are horizontal directions, and the Z-axis direction is vertical direction.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In addition, in each drawing, the same reference numerals are given to the same or corresponding configurations, and explanations thereof may be omitted.

(Gel manufacturing equipment)
As shown in FIGS. 1A and 1B, the source liquid layer A is thinned and then gelled on the surface of the base liquid layer B, which has a higher density than the source liquid layer A, to form a gel layer C. Become.

The manufacturing apparatus 1 has a storage section 2 that stores the base liquid layer B. As shown in FIG. The housing portion 2 includes, for example, a mold 21 and a bottom lid 22 that closes the opening of the mold 21 from below. The mold 21 protrudes upward from the entire peripheral edge of the bottom lid 22 . The bottom lid 22 supports the base liquid layer B from below and contacts the lower surface of the base liquid layer B. As shown in FIG.

The mold 21 surrounds the liquid surface of the base liquid layer B. As shown in FIG. A raw material liquid layer A is formed on the liquid surface. The raw material liquid layer A is thinned and subsequently gelled to form a gel layer C. As shown in FIG. Therefore, the shape and size of the opening of the mold 21 are appropriately determined according to the shape and size of the gel layer C as a product.

The shape of the opening of the mold 21 may be circular or elliptical in addition to the rectangular shape shown in FIG. 2 in plan view. Rectangles include not only those with square corners, but also those with rounded corners. A rectangle contains a square.

The height of the mold 21 is determined so that the raw material liquid layer A before thinning shown in FIG. 1A does not overflow from the mold 21 . Although the details will be described later, the raw material liquid is supplied so as to spread over the entire liquid surface surrounded by the mold 21, and part of it is discharged for the purpose of thinning the raw material liquid layer A. The supply amount of the raw material liquid may be determined so that the discharge amount is as small as possible.

The material of the mold 21 is not particularly limited as long as it does not deteriorate or swell with the raw material liquid and the base liquid and does not react with the raw material liquid layer A and the base liquid layer B, and may be metal, resin, rubber, glass, or the like. and ceramic. When manufacturing a gel layer C with a large area, a metal such as stainless steel is suitable from the viewpoint of load resistance. A side surface of the metal mold 21 may be coated with a resin. Moreover, when the raw material layer A is heated during the gelation of the raw material liquid layer A, the material of the mold 21 may be any material as long as it can withstand the heating temperature of the raw material liquid layer A. The material of the bottom lid 22 may be the same as the material of the formwork 21 .

The manufacturing apparatus 1 has a raw material liquid supply unit 3 that supplies the raw material liquid of the gel onto the liquid surface of the base liquid layer B. As shown in FIG. The total supply volume V _A of the raw material liquid can be obtained, for example, from the volume V _C of the gel layer C as a product and the volume shrinkage rate r from the raw material liquid layer A to the gel layer C. The volume shrinkage ratio r is the difference between the volume V _A before shrinkage and the volume V _C after shrinkage (V _A −V _C ) divided by the volume V _A before shrinkage ((V _A −V _C )/ V _A ), which is determined in advance by experiments or the like. Further, the total supplied mass W _A of the raw material liquid is obtained, for example, as the product of the total supplied volume V _A of the raw material liquid and the density ρ _A of the raw material liquid. The density _ρA of the raw material liquid is obtained in advance by experiments or the like.

A raw material liquid supply unit 3 supplies a raw material liquid to form a raw material liquid layer A. FIG. The raw material liquid layer A is in contact with the entire inner periphery of the mold 21 as shown in FIG. The source liquid layer A is formed on the entire liquid surface surrounded by the mold 21 of the base liquid layer B. As shown in FIG. Since the base liquid layer B has a higher density than the source liquid layer A, the source liquid layer A can be stably formed on the base liquid layer B.

Since the liquid surface of the base liquid layer B is naturally leveled horizontally by gravity, the flat raw material liquid layer A having a uniform thickness can be easily obtained by utilizing the horizontal liquid surface. In addition, since the liquid surface of the base liquid layer B flows according to the expansion and contraction of the raw material liquid layer A during gelation and the removal of the gel layer C, the stress applied to the gel layer C is small and defects in the gel layer C are reduced. Less is. Furthermore, since the entire lower surface of the gel layer C is horizontally supported, the area of the gel layer C can be increased.

A gel layer C obtained on the liquid surface of the base liquid layer B is a wet gel containing a solvent as a swelling agent. The wet gel has a thickness of, for example, 0.1 mm to 20 mm, preferably 0.5 mm to 10 mm. The wet gel is dried and becomes a xerogel. The thickness of the xerogel is, for example, 0.1 mm to 20 mm, preferably 0.5 mm to 10 mm. Xerogels may be porous monoliths that are transparent and thermally insulating. Xerogels, which are transparent and thermally insulating, are used, for example, as transparent thermal insulators in automotive glazings and building glazings.

When the xerogel is used as a transparent heat insulating material, the transmittance of the xerogel at a wavelength of 500 nm is preferably 70% or more, preferably 80% or more, and preferably 90% or more in terms of thickness of 1 mm. The transmittance is measured according to Japanese Industrial Standards (JIS R 3106:1998).

Applications of xerogels include, for example, filters, adsorbents, sound absorbers, moisture absorbers, oil absorbers, and separation membranes, in addition to heat insulators. Xerogels may be non-transparent or opaque, depending on the application.

The type of xerogel is (1) polysiloxane xerogel in this embodiment, but may be (2) polymer xerogel or (3) polysaccharide xerogel such as cellulose xerogel.

The raw material liquid includes, for example, a gel raw material (hereinafter also referred to as "gel raw material") and a solvent that dissolves the gel raw material. The gel raw material is appropriately selected according to the type of xerogel to be finally obtained. Solvents are, for example, water or organic solvents. Examples of organic solvents include alcohols (methanol, ethanol, isopropyl alcohol, tert-butyl alcohol, benzyl alcohol, etc.), aprotic polar organic solvents (N,N-dimethylformamide, dimethylsulfoxide, N,N-dimethylacetamide, etc.), Examples include ketones (cyclopentanone, cyclohexanone, methyl ethyl ketone, methyl isobutyl ketone, acetone, etc.), hydrocarbons (n-hexane, heptane, etc.), and the like.

When the xerogel is (1) a polysiloxane xerogel, the gel raw material includes, for example, (1A) a silane compound and (1B) a catalyst. (1B) The catalyst is for uniformly promoting gelation. The gel raw material may further contain (1C) a surfactant.

(1A) Silane compounds include alkoxysilanes, 6-membered ring-containing silane compounds having a 6-membered ring-containing skeleton and a hydrolyzable silyl group, silyl group-containing polymers having an organic polymer skeleton and a hydrolyzable silyl group, and the like. mentioned.

Examples of alkoxysilanes include tetraalkoxysilanes (tetramethoxysilane, tetraethoxysilane, etc.), monoalkyltrialkoxysilanes (methyltrimethoxysilane, methyltriethoxysilane, etc.), dialkyldialkoxysilanes (dimethyldimethoxysilane, dimethyldiethoxysilane, etc.). etc.), trimethoxyphenylsilane, compounds having alkoxysilyl groups at both ends of the alkylene group (1,6-bis(trimethoxysilyl)hexane, 1,6-bis(methyldimethoxysilyl)hexane, 1,6-bis (methyldiethoxysilyl)hexane, 1,2-bis(trimethoxysilyl)ethane, 1,2-bis(methyldimethoxysilyl)ethane, 1,2-bis(methyldiethoxysilyl)ethane, etc.), perfluoropolyether alkoxysilanes having a group (perfluoropolyethertriethoxysilane, perfluoropolyethermethyldiethoxysilane, etc.), alkoxysilanes having a perfluoroalkyl group (perfluoroethyltriethoxysilane, etc.), pentafluorophenylethoxydimethylsilane, trimethoxy(3, 3,3-trifluoropropyl)silane, alkoxysilanes having a vinyl group (vinyltrimethoxysilane, vinyltriethoxysilane, dimethoxymethylvinylsilane, diethoxymethylvinylsilane, etc.), alkoxysilanes having an allyl group (allyltrimethoxysilane, allyldimethoxymethylsilane, allyldiethoxymethylsilane, etc.), alkoxysilanes having an epoxy group (2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxy propylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, etc.), alkoxysilanes having an acryloyloxy group (3-acryloyloxypropyltrimethoxysilane, 3-acryloyloxypropylmethyldimethoxysilane, etc.), methacryloyloxy groups alkoxysilanes (3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, etc.) and oligomers of the above alkoxysilanes.

The 6-membered ring-containing skeleton in the 6-membered ring-containing silane compound is an organic skeleton having at least one 6-membered ring selected from the group consisting of isocyanuric rings, triazine rings and benzene rings.

The organic polymer backbone in the silyl group-containing polymer is an organic backbone having at least one chain selected from the group consisting of polyethylene chains, polyether chains, polyester chains and polycarbonate chains.

(1B) Catalysts include base catalysts and acid catalysts, and aqueous solutions thereof may be used. Examples of basic catalysts include amines (triethylamine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, etc.), urea, ammonia, sodium hydroxide, potassium hydroxide and the like. Acid catalysts include inorganic acids (nitric acid, sulfuric acid, hydrochloric acid, etc.) and organic acids (formic acid, oxalic acid, acetic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monofluoroacetic acid, trifluoroacetic acid, etc.).

(1C) Surfactants include, for example, hexadecyltrimethylammonium bromide, hexadecyltrimethylammonium chloride, Pluronic F127 (trade name of BASF), and EH-208 (trade name of NOF Corporation).

When the xerogel is (2) a polymer xerogel, examples of gel raw materials include thermoplastic resins and curable resins.

Examples of thermoplastic resins include those that can be dissolved in a solvent when heated and can form a monolith (porous body) when cooled. Specific examples include polymethyl methacrylate and polystyrene.

The curable resin includes a photocurable resin and a thermosetting resin. Examples of photocurable resins include those containing either one or both of acrylate and methacrylate and a photopolymerization initiator. Examples of thermosetting resins include those containing either or both of acrylate and methacrylate and a thermal polymerization initiator, addition condensates of resorcinol and formaldehyde, addition condensates of melamine and formaldehyde, and the like. be done.

When the xerogel is (3) polysaccharide xerogel, the gel raw material includes (3A) polysaccharide nanofibers and (3B) acid. Polysaccharides include chitin, chitosan, gellan gum, etc., in addition to cellulose.

(3A) Polysaccharide nanofibers include 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) oxidized cellulose nanofibers. (3A) Examples of polysaccharide nanofibers include cellulose nanofibers, chitin nanofibers, chitosan nanofibers, and the like.

(3B) Acids include the above inorganic acids and the above organic acids. Bases can also be used instead of acids.

The base liquid layer B preferably has a large difference in density from the raw liquid layer A so that the raw liquid layer A can stably exist thereon. The density difference is preferably 0.1 g/cm ³ or more, more preferably 0.5 g/cm ³ or more. From the viewpoint of weight reduction, the density difference is preferably 3.0 g/cm ³ or less, more preferably 2.0 g/cm ³ or less.

Moreover, the base liquid layer B preferably has low compatibility with the raw material liquid layer A so that the raw material liquid layer A can stably exist thereon. The compatibility between the base liquid layer B and the raw material liquid layer A can be estimated by the upper limit amount of the raw material liquid that can be dissolved in 100 g of the base liquid layer B liquid. The upper limit is preferably 100 g or less, more preferably 10 g or less, and even more preferably 1 g or less. If the upper limit amount is 100 g or less, the separated state of the base liquid layer B and the raw material liquid layer A can be maintained for a long time. The upper limit is preferably as small as possible, and may even be 0 g.

Further, it is preferable to use a base liquid layer B that does not react with the source liquid layer A so that the source liquid layer A can stably exist thereon. Preferably, the base liquid layer B does not substantially contain gel raw materials. “Substantially free of gel raw material” means that the gel raw material other than the gel raw material transferred from the raw material liquid layer A is not contained.

The base liquid is appropriately selected according to the solvent of the raw material liquid. Examples of base liquids include liquid compounds having fluorine atoms, liquid compounds having chlorine atoms, liquid compounds having silicon atoms, water, mercury, etc. If there is a density difference from the raw liquid, fluorine, chlorine, bromine Alternatively, it need not contain halogen atoms such as iodine, silicon atoms, or the like. The water may contain a water-soluble salt to adjust the density of the base liquid layer B. Water-soluble salts include sodium chloride and the like.

A liquid compound having a fluorine atom is excellent in that it has a high density, a high boiling point, high thermal decomposition resistance, and nonflammability. Examples of liquid compounds having fluorine atoms include fluorine-based solvents and fluorine-based oils.
Fluorinated solvents include hydrofluoroalkanes, chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluoromonoethers, perfluoromonoethers, perfluoroalkanes, perfluoropolyethers, perfluoroamines, fluorine-containing alkenes, fluorine-containing aromatic compounds, fluorine Atom-containing ketones, fluorine atom-containing esters, and the like can be mentioned. Commercially available fluorinated solvents include Asahiklin AK-225 (CF ₃ CF ₂ CHCl ₂ ), AC-2000 (CF ₃ CF ₂ CF ₂ CF ₂ CF ₂ CHF ₂ ), AC-6000 (registered trademark of Asahi Glass Co., Ltd.). CF ₃ CF ₂ CF ₂ CF ₂ CF ₂ CF ₂ CH ₂ CH ₃ ), AE- _{3000 (} CF ₃ CH _{2 OCF 2} CHF ₂ ); 7200 _{( C4F9OC2H5} ), 7300 _{( C2F5CF ( OCH3} )CF _{( CF3} ) ₂ ); _Vertrel XF _{( CF3CHFCHFC2F5} ), a trade name of Mitsui DuPont Fluorochemicals. , MCA, XH; and Zeorora H (heptafluorocyclopentane), a trade name of Nippon Zeon Co., Ltd., and the like.
Commercially available fluorinated oils include Fomblin (trade name of Solvay), Demnum (trade name) of Daikin Industries, and Daifloil (trade names of Daikin Industries, Ltd.).

Examples of liquid compounds having chlorine atoms include chlorine-based solvents and chlorine-based oils. Examples of chlorinated solvents include carbon tetrachloride, chloroform, and methylene chloride.

Silicone oil etc. are mentioned as a liquid compound which has a silicon atom. Examples of silicone oil include dimethylsilicone oil and methylphenylsilicone oil. Commercially available silicone oils include KF-96 (trade name of Shin-Etsu Chemical Co., Ltd.).

The thickness of the base liquid layer B may be, for example, 10 mm or more so that the raw material liquid does not break through the base liquid layer B and reach the bottom lid 22 when the raw material liquid is supplied. This is because, once the raw material liquid reaches the bottom lid 22, it adheres to the bottom lid 22 due to the wetting effect and remains submerged. If the thickness of the base liquid layer B is thick, the supply speed of the raw material liquid can be increased.

The raw material liquid supply unit 3 includes, for example, a storage tank 31 that temporarily stores the raw material liquid. The storage tank 31 may be, for example, a mixing tank for mixing (1A) the silane compound and (1B) the catalyst. The mixing tank may include a cooling device for cooling the raw material liquid in order to suppress the progress of gelation. The temperature of the mixing tank is preferably as low as possible from the viewpoint of suppressing the progress of gelation, but may be set higher than the freezing point of the raw material liquid from the viewpoint of freezing prevention, and is set to, for example, 0°C to 20°C.

The mixing tank may include a stirring device for stirring the raw material liquid. The silane compound and the catalyst can be mixed in a short time, and the raw material liquid can be homogenized in a short time.

Although not shown, the mixing tank is connected to a silane compound supply source through a first pipe and to a catalyst supply source through a second pipe. The first pipe is provided with a first flow rate controller for controlling the flow rate of the silane compound, and the second pipe is provided with a second flow rate controller for controlling the flow rate of the catalyst. Since the flow rate of the silane compound and the flow rate of the catalyst can be controlled, the residence time in the mixing tank can be shortened. The flow rate of the silane compound and the flow rate of the catalyst are appropriately determined according to the flow rate of the raw material liquid supplied onto the base liquid layer B.

The raw material liquid supply unit 3 includes a discharge nozzle 32 that supplies the raw material liquid supplied from the storage tank 31 to the inside of the mold 21 . The ejection nozzle 32 supplies the raw material liquid onto the liquid surface of the base liquid layer B. As shown in FIG. The discharge nozzle 32 may be arranged at a position close to the liquid surface of the base liquid layer B so that the raw material liquid does not break through the base liquid layer B when the raw material liquid is supplied, and may be arranged inside the mold 21 . .

As shown in FIG. 1A, the discharge nozzle 32 is arranged inside the mold 21 and is configured to be movable between a position where the raw material is supplied and a position outside the mold 21 when supplying the raw material. may be After the raw material liquid layer A is gelled, when the gel layer C is removed from the mold 21, the discharge nozzle 32 can be retracted to the outside of the mold 21, and interference between the discharge nozzle 32 and the gel layer C can be prevented.

Further, the raw material liquid supply unit 3 includes a supply pump 34 that feeds the raw material liquid in the middle of the supply line 33 that connects the storage tank 31 and the discharge nozzle 32 . When the supply pump 34 is operated, the discharge nozzle 32 discharges the raw material liquid. On the other hand, when the operation of the supply pump 34 is stopped, the discharge nozzle 32 stops discharging the raw material liquid.

Moreover, the raw material liquid supply unit 3 may include a flow meter that measures the flow rate of the raw material liquid in the middle of the supply line 33 . The flow rate may be volume flow rate or mass flow rate. By integrating the flow rate over time, the total supply amount of the raw material liquid can be calculated, and it can be checked whether or not the total supply amount of the raw material liquid has reached the target value. The total feed can be either volume or mass. When the total supply amount of the raw material liquid reaches the target value, the supply of the raw material liquid is stopped.

Moreover, the raw material liquid supply unit 3 may include a mass meter that measures the mass change of the storage tank 31 . Since the mass reduction amount of the storage tank 31 is equal to the total supplied mass of the raw material liquid, it is possible to check whether or not the total supplied mass of the raw material liquid has reached the target value. When the total supply mass of the raw material liquid reaches the target value, the supply of the raw material liquid is stopped.

As shown in FIG. 2 , the raw material supply unit 3 supplies the raw material liquid so as to spread over the entire liquid surface surrounded by the mold 21 to form a raw material liquid layer A in contact with the entire inner periphery of the mold 21 . The entire outer circumference of the raw material liquid layer A contacts the mold 21 .

As shown in FIG. 3A, when the material liquid layer A is separated from the entire inner periphery of the mold 21, the thickness H _A of the material liquid layer A becomes the equilibrium thickness H _A0 . At this time, the first inward force F1 and the first outward force F2 are balanced over the entire outer periphery of the raw material liquid layer A.

The first inward force F1 is generated by the surface tension of the source liquid layer A, shrinks the source liquid layer A inward, and increases the thickness HA of the source liquid layer _A. On the other hand, the first outward force F2 is caused by gravity, spreads the raw material layer A outward, and reduces the thickness HA of the raw material layer _A. FIG. The first outward force F2 is caused by gravity and therefore depends on the thickness HA of the raw material layer _A. The greater the thickness _HA , the greater the first outward force F2.

From the state shown in FIG. 3A, when the thickness H _A of the source liquid layer A becomes larger than the equilibrium thickness H _A0 due to disturbance, the first outward force F2 becomes larger than the first inward force F1. spreads outward, the thickness H _A of the source liquid layer A becomes thinner and returns to the equilibrium thickness H _A0 .

On the other hand, when the thickness H _A of the source liquid layer A becomes smaller than the equilibrium thickness H _A0 due to disturbance from the state shown in FIG. 3A, the first outward force F2 becomes smaller than the first inward force F1. The layer A shrinks inward, and the thickness H _A of the source liquid layer A increases and returns to the equilibrium thickness H _A0 .

Therefore, when the material liquid layer A is separated from the entire inner periphery of the mold 21, the thickness H _A of the material liquid layer A becomes the equilibrium thickness H _A0 .

As shown in FIGS. 3B and 3C, when the raw material liquid layer A is in contact with the entire inner periphery of the mold 21, the entire outer periphery of the raw material liquid layer A is adsorbed to the mold 21, and the adsorption causes the second outward A force F3 is produced. Since the second outward force F3 is generated by adsorption, it depends on the contact area between the raw material layer _A and the mold 21, in other words, the thickness HA of the raw material layer A. The greater the thickness _HA , the greater the second outward force F3.

As shown in FIGS. 3B and 3C, when the resultant force of the first outward force F2 and the second outward force F3 is greater than the first inward force F1, the mold 21 pushes back the raw material liquid layer A. , a second inward force F4 is generated by the pushing back. The second inward force F4 may be zero as it is generated to keep the balance of forces, in other words to balance the balance. The second inward force F4 is not used for thinning the raw material liquid layer A.

According to this embodiment, the raw material liquid is supplied so as to spread over the entire liquid surface surrounded by the mold 21, and the raw material liquid layer A is formed in contact with the entire inner circumference of the mold 21. A second outward force F3 acts on the entire circumference. Since the entire outer periphery of the raw material layer A is pulled outward by the second outward force F3, the raw material liquid is discharged from the raw material layer A as described later, and the thickness H _A of the raw material layer A is increased as shown in FIG. 3C. can be made thinner than the equilibrium thickness H _A0 . The thickness H _A of the raw material layer A before thinning is equal to or greater than the equilibrium thickness H _A0 as shown in FIG. 3B.

However, the thinner the thickness HA of the raw material liquid layer _A , the smaller the second outward force F3, as described above. The same applies to the first outward force F2. As shown in FIG. 3C, the raw material layer A is thinned in a range in which the resultant force of the first outward force F2 and the second outward force F3 exceeds the first inward force F1. This is because if the resultant force becomes smaller than the first inward force F1, the balance of the forces will be lost, and the raw material liquid layer A will break.

The larger the surface tension of the mold 21, the easier it is for the raw material layer A to be adsorbed on the side surface of the mold 21. Therefore, the second outward force F3 is large, and the raw material liquid layer A can be made thinner. The second outward force F3 depends on the surface tension of the raw material liquid layer A in addition to the surface tension of the mold 21. The smaller the contact angle of the raw material liquid with respect to the mold 21, the better the wettability. The directional force F3 increases. The contact angle is preferably less than 90°. When the material of the mold 21 is resin, among resins, nylon, polyester, etc. are suitable for thinning the raw material liquid layer A because of their high surface tension.

Further, as shown in FIG. 3D , unevenness 211 may be formed at least at a portion of the side surface of the mold 21 that comes into contact with the raw material liquid layer A. As shown in FIG. The shape of the unevenness 211 is triangular in FIG. 3D, but may be rectangular or sinusoidal, and is not particularly limited. The unevenness 211 can increase the contact area between the mold 21 and the raw material layer A, and can increase the second outward force F3 generated by adsorption, so that the thickness _HA can be further reduced.

However, when unevenness 211 is formed on the side surface of the mold 21 as shown in FIG. 3D, the shape of the unevenness 211 is transferred to the side surface of the gel layer C. As shown in FIGS. 3B and 3C, if the side surface of the mold 21 does not have unevenness 211, the side surface of the gel layer C is smooth.

Since the gel layer C does not contact the bottom lid 22, the shape of the top surface of the bottom lid 22 is not transferred to the bottom surface of the gel layer C. Therefore, the roughness of the upper surface of the bottom lid 22 does not become a problem, and a special process for smoothing the upper surface of the bottom lid 22 surrounded by the mold 21 is not required.

As shown in FIGS. 1A and 1B, the manufacturing apparatus 1 discharges the raw material liquid from the raw material liquid layer A, which is in contact with the entire inner circumference of the mold 21, to the outside of the mold 21, thereby thinning the raw material liquid layer A. It has a raw material liquid suction part 5 . Since the raw material liquid is discharged from the raw material liquid layer A in a state where the entire outer periphery of the raw material liquid layer A is pulled outward by the second outward force F3, the thickness H _A of the raw material liquid layer A is made larger than the equilibrium thickness H _A0 . It can be made thin.

In addition, the raw material liquid layer A does not have to be in contact with the entire inner periphery of the mold 21, and the raw material liquid layer A does not break when the raw material liquid layer A is thinned. It is only necessary to substantially touch the entire inner periphery. In other words, the entire outer periphery of the raw material layer A should be substantially in contact with the mold 21 to the extent that the raw material layer A does not break when the raw material layer A is thinned. As long as there are some small bubbles at the interface between the raw material layer A and the mold 21, the raw material layer A will not break when the raw material layer A is thinned. Also, a gap that can be immediately filled by fluctuations in the system is allowed.

The raw material liquid suction unit 5 includes, for example, a suction nozzle 51 that discharges the raw material liquid from the raw material liquid layer A to the outside of the mold 21 . The position of the suction port 52 of the suction nozzle 51 may be lower than the upper surface of the thinned raw material layer A, but it should be at the same height as the upper surface of the thinned raw material layer A. you can In the latter case, if the height of the suction port 52 of the suction nozzle 51 is determined, the thickness of the raw material layer A after thinning is determined regardless of whether or not the suction nozzle 51 is operated. The accuracy of timing control can be relaxed. In the former case, the suction nozzle 51 is pulled out from the raw material layer A before the raw material layer A is gelled.

The suction nozzle 51 is arranged inside the mold 21 when sucking the raw material liquid from above the raw material liquid layer A as shown in FIGS. 1A and 1B. Therefore, the suction nozzle 51 may be configured to be movable between the position where the raw material liquid is discharged and the position outside the mold 21, similarly to the discharge nozzle 32. FIG. After the raw material liquid layer A is gelled, when the gel layer C is removed from the mold 21, the suction nozzle 51 can be retracted to the outside of the mold 21, and interference between the suction nozzle 51 and the gel layer C can be prevented.

Although the suction nozzle 51 discharges the raw material liquid from above the raw material liquid layer A in FIGS. 1A and 1B, the raw material liquid may be discharged from the side of the raw material liquid layer A. FIG. In this case, a through hole is formed in the mold 21, and the suction nozzle 51 is inserted into the through hole. If the suction nozzle 51 discharges the raw material liquid from the side of the raw material liquid layer A, after the raw material liquid layer A is gelled, when the gel layer C is taken out from the mold 21, the suction nozzle 51 and the gel layer C will be separated from each other. Interference can be prevented.

The raw material liquid suction unit 5 includes a collection tank 53 that collects the raw material liquid discharged by the suction nozzle 51 . The raw material liquid suction unit 5 also includes a suction pump 55 that feeds the raw material liquid in the middle of the recovery line 54 that connects the suction nozzle 51 and the recovery tank 53 . When the suction pump 55 is operated, the suction nozzle 51 discharges the raw material liquid. On the other hand, when the operation of the suction pump 55 is stopped, the suction nozzle 51 stops discharging the raw material liquid.

As shown in FIG. 1B, the manufacturing apparatus 1 includes a gelation promoting section 6 that gels the thinned raw material liquid layer A on the liquid surface of the base liquid layer B. As shown in FIG. When the gel raw material contains (1A) a silane compound and (1B) a catalyst, the raw material liquid layer A is gelled by heating. A silane compound is hydrolyzed with an acid catalyst or the like to form a sol having a silanol group (Si—OH). When the sol is heated, the silanol groups undergo a dehydration condensation reaction between molecules to form Si--O--Si bonds, and the raw material liquid layer A is gelled.

The gelation promoting unit 6 has a heater 61 that heats the raw material liquid layer A, for example. The heater 61 may be arranged outside or inside the housing portion 2, or may be arranged both outside and inside.

When the heater 61 is arranged inside the housing portion 2, it is arranged inside, for example, the base liquid layer B, and by heating the base liquid layer B, the source liquid layer A is heated from below. In addition, when the heater 61 is arranged outside the storage section 2 , the heater 61 may be arranged at least one of above, beside, and below the raw material liquid layer A. The heater 61 is preferably arranged so as to heat the raw material liquid layer A from both upper and lower sides. Moreover, the heater 61 is preferably arranged so as to heat the entire outer circumference of the raw material liquid layer A from the side.

The heating method of the heater 61 is not particularly limited, but is appropriately selected from, for example, a resistance heating method, an infrared heating method, an arc heating method, and the like, depending on the installation location of the heater 61 .

Note that means for gelling the raw material liquid layer A is not limited to the heater, and may be appropriately selected according to the type of gel raw material.

For example, when the gel raw material is a thermoplastic resin, the means for gelling the raw material liquid layer A is a cooler. The cooler cools the source liquid layer A on the base liquid layer B, causing the source liquid layer A to gel. Coolers may also be positioned and controlled in the same manner as heaters. Instead of forced cooling by a cooler, natural cooling may be implemented.

Further, when the gel raw material is a photocurable resin, means for gelling the raw material liquid layer A is a light source. The light source irradiates the source liquid layer A present on the base liquid layer B with light such as ultraviolet rays to cure the photocurable monomer and gel the source liquid layer A. FIG. Light sources may also be positioned and controlled in the same manner as heaters.

Further, when the gel raw material is a thermosetting resin, means for gelling the raw material liquid layer A is a heater.

In addition, when the gel raw material is polysaccharide nanofibers, the polysaccharide nanofibers gel in a short time upon contact with an acid catalyst or a base catalyst. Therefore, the raw material liquid may contain polysaccharide nanofibers and not contain an acid catalyst or a base catalyst. The acid catalyst or base catalyst may be supplied to the source liquid layer A formed on the base liquid layer B from above in the form of a shower. In this case, means for gelling the raw material liquid layer A is a feeder for supplying an acid catalyst or a basic catalyst to the raw material liquid layer A from above.

In the final stage of gelation of the raw material layer A, hardening shrinkage occurs, so the outer periphery of the gel layer C may be peeled off from the mold 21 due to the hardening shrinkage. Since the size of the gel layer C is smaller than the size of the opening of the mold 21, it is easy to remove the gel layer C from the mold 21. - 特許庁

By the way, in the process of gelling the raw liquid layer A on the liquid surface of the base liquid layer B, the raw liquid layer A shrinks on hardening, and the solvent may be pushed out from the inside of the gel layer C. The solvent itself is easy to evaporate, but the catalyst or surfactant dissolved in the solvent suppresses the evaporation of the solvent. As a result, even after the gel layer C is removed from above the liquid surface of the base liquid layer B, the solvent pushed out from the inside of the gel layer C stays on the liquid surface of the base liquid layer B. Formation or gelation can be inhibited.

Therefore, after removing the gel layer C from above the liquid surface of the base liquid layer B, the manufacturing apparatus 1 removes the solvent of the raw material liquid accumulated on the liquid surface as shown in FIGS. 4A and 4B. , the base liquid may be supplied to the interior of the housing portion 2 . As the base liquid is supplied, the thickness of the base liquid layer B increases from the thickness shown in FIG. 4A to the thickness shown in FIG. , is removed. This operation may be performed periodically.

The manufacturing apparatus 1 has a base liquid supply section 7 that supplies the base liquid to the inside of the container section 2 . The base liquid supply section 7 includes, for example, a storage tank 71 that temporarily stores the base liquid, and a supply nozzle 72 that supplies the base liquid supplied from the storage tank 71 to the inside of the storage section 2 . The supply nozzle 72 supplies the base liquid below the liquid surface of the base liquid layer B in order to prevent the solvent of the raw material liquid accumulated above the liquid surface of the base liquid layer B from mixing with the newly supplied base liquid. Dispense.

The base liquid supply unit 7 includes a supply pump 74 that feeds the base liquid in the middle of the supply line 73 that connects the storage tank 71 and the supply nozzle 72 . When the supply pump 74 is operated, the supply nozzle 72 discharges the base liquid. On the other hand, when the operation of the supply pump 74 is stopped, the supply nozzle 72 stops discharging the base liquid.

The base liquid supply section 7 supplies the base liquid to the inside of the storage section 2 until the liquid surface of the base liquid layer B reaches or exceeds the lowest portion of the upper end of the storage section 2 , for example. A portion of the upper end of the container 2 is lower than the remaining portion so that the liquid overflows from a specific portion. In other words, a notch N is formed in a part of the upper end of the storage portion 2, and the liquid overflows from the notch N.

The manufacturing apparatus 1 may have a recovery section 8 that recovers the liquid overflowing from the upper end of the storage section 2 in order to keep the surroundings of the storage section 2 clean. The recovery unit 8 recovers liquid overflowing from a specific portion of the upper end of the storage unit 2 . Since the recovered liquid contains multiple components, it may be discarded or recycled after purification.

The manufacturing apparatus 1 has a drain line 75 for discharging the base liquid from the base liquid layer B and an opening/closing valve 76 provided in the middle of the drain line 75 in order to restore the thickness of the base liquid layer B to the original thickness. You can When the open/close valve 76 is opened, the base liquid is discharged from the base liquid layer B, and the thickness of the base liquid layer B returns to its original thickness. The discharged base liquid may be discarded or recycled.

If the supply pump 74 feeds the base liquid in both directions, the supply nozzle 72 can discharge the base liquid from the base liquid layer B and send it back to the storage tank 71 . In this case, the drainage line 75 and the opening/closing valve 76 are unnecessary.

Since the degree of curing shrinkage of the raw liquid layer A differs depending on the type of gel, the amount of solvent pushed out from the gel layer C also differs depending on the type of gel. Therefore, the base liquid supply unit 7, the recovery unit 8, and the like may be unnecessary, and may be installed according to the type of gel.

(Gel manufacturing method)
As shown in FIG. 5, the gel manufacturing method includes, for example, formation of a raw material liquid layer A (S1), thinning of the raw material liquid layer A (S2), gelation of the raw material liquid layer A (S3), It has extraction of the gel layer C (S4), solvent replacement of the gel layer C (S5), and drying of the gel layer C (S6).

The formation of the raw material liquid layer A (S1), the thinning of the raw material liquid layer A (S2), and the gelation of the raw material liquid layer A (S3) are performed by the manufacturing apparatus 1, for example. Descriptions of S1 to S3 are omitted because they are as described above.

The remaining steps of taking out the gel layer C (S4), replacing the solvent in the gel layer C (S5), and drying the gel layer C (S6) will be described below.

Note that the method for producing a gel may not include all the processes shown in FIG. 5. For example, if the solvent of the raw material liquid is suitable for drying (S6), the solvent replacement (S5) may not be performed. . Also, the gel manufacturing method may include a process different from the process shown in FIG.

In take-out (S4), the gel layer C is lifted from the base liquid layer B and taken out from the mold 21. As shown in FIG. In the final stage of gelation (S3), if the magnitude of curing shrinkage of the material liquid layer A is large, the outer periphery of the gel layer C is separated from the mold 21, so the container 2 should be tilted as shown in FIG. is unnecessary, and the gel layer C can be easily taken out.

As shown in FIG. 6, if the containing portion 2 is tilted while the gel layer C exists on the base liquid layer B, the liquid surface of the base liquid layer B tends to become horizontal. 6 changes from the state shown by the two-dot chain line in FIG. 6 to the state shown by the solid line in FIG. In addition, when the containing portion 2 is tilted, the area of the liquid surface of the base liquid layer B increases, whereas the area of the lower surface of the gel layer C does not change. By tilting the housing part 2 in this way, it is possible to remove the gel layer C from the formwork 21 without applying excessive force to the gel layer C, and the gel layer C can be easily taken out.

As shown in FIG. 7 , the storage unit 2 includes, in addition to the form 21 , a container 24 for accommodating the form 21 , a support plate 25 installed under the form 21 , and a support plate 25 for supporting the support plate 25 . bar 26; The support plate 25 is used in place of the bottom cover 22 shown in FIGS. 1A and 1B, and the formwork 21 is placed on the support plate 25 in a separable manner.

The container 24 includes a bottom plate 241 and side plates 242 extending upward from the entire periphery of the bottom plate 241 . A base liquid layer B is formed inside the container 24 , and a part of the liquid surface of the base liquid layer B is surrounded by the mold 21 . The formwork 21 is spaced apart from the side plates 242 of the container 24 .

The raw material liquid layer A is formed inside the mold 21 and not formed outside the mold 21 . The mold 21 protrudes below the interface between the raw material liquid layer A and the base liquid layer B, and also protrudes above the upper surface of the raw material liquid layer A. As shown in FIG.

The support plate 25 is placed below the interface between the base liquid layer B and the raw material layer A before forming the raw material layer A on the liquid surface of the base liquid layer B. As shown in FIG. The support plate 25 supports the gel layer C from below when the gel layer C is lifted from the base liquid layer B. As shown in FIG. Since the support plate 25 supports the gel layer C from below, cracking of the gel layer C due to gravity can be suppressed.

The support plate 25 may have a plurality of through holes H passing through the front and back surfaces of the support plate 25 at intervals in the main surface direction of the support plate 25 . As the support plate 25, for example, punching metal or wire mesh is used. When the gel layer C is lifted from the base liquid layer B, the base liquid existing above the support plate 25 passes through the through holes H and escapes below the support plate 25 . Therefore, since the support plate 25 and the gel layer C are in direct contact with each other, the slippage of the gel layer C can be suppressed by friction, and the fall of the gel layer C from the support plate 25 can be suppressed.

In the final stage of gelation (S3), if the degree of cure shrinkage of the raw material liquid layer A is small and the outer periphery of the gel layer C does not separate from the mold 21, the mold 21 is disassembled into a plurality of parts and the gel layer is formed. can be removed from C. This is because the formwork 21 is arranged apart from the side plate 242 of the container 24, so that a working space for disassembling the formwork 21 into a plurality of parts can be secured between the side plate 242 and the formwork 21.例文帳に追加

On the other hand, in the final stage of gelation (S3), when the hardening shrinkage of the raw material layer A is large and the outer periphery of the gel layer C separates from the mold 21, the mold 21 is disassembled into a plurality of parts. However, the mold 21 can be removed from the gel layer C without disassembling.

After removing the formwork 21 from the gel layer C, the gel layer C can be supported by the support plate 25 by pulling up the support rods 26 . In this state, the support plate 25 and the gel layer C may be immersed in a solvent stored in a container different from the container 24 to perform solvent replacement (S5). In this case, if the support plate 25 has the through holes H, the solvent can be replaced from the front and back sides of the gel layer C.

However, the solvent replacement (S5) can also be performed inside the container 24. FIG. In that case, the inside of the container 24 is once emptied, and the solvent that replaces the solvent contained in the gel layer C is stored inside the container 24 . When the solvent contained inside the gel layer C is water, the solvent that replaces water usually has a lower density than water, so the gel layer C sinks in the solvent that replaces water, and the solvent replacement is efficient. done on purpose. Also in this case, if the support plate 25 has the through hole H, the solvent replacement can be performed from the front and back sides of the gel layer C.

In the solvent replacement (S5), the solvent contained inside the gel layer C is replaced with another solvent. The gel layer C is a fine porous body containing a solvent inside. Solvent replacement (S5) is performed before drying (S6) for the purpose of suppressing shrinkage of the gel layer C due to the surface tension of the solvent during drying and suppressing breakage of the microstructure of the gel layer C. be implemented.

In the solvent replacement, the solvent contained inside the gel layer C is replaced from the solvent suitable for gelation (that is, the solvent of the raw material liquid) with the solvent suitable for drying. The solvent after substitution is appropriately selected according to the drying method. As a drying method, supercritical drying, freeze drying, or normal pressure drying is used.

Supercritical drying replaces the solvent contained inside the gel layer C with a supercritical fluid. Solvents suitable for supercritical drying include, for example, methanol, ethanol, or isopropyl alcohol. Carbon dioxide gas in a supercritical state is generally used as the supercritical fluid. Supercritical drying is carried out inside a closed high-pressure vessel.

Freeze-drying freezes the solvent contained inside the gel layer C and then evaporates it in a vacuum. This is commonly called sublimation. Solvents suitable for freeze-drying include water, tert-butyl alcohol, cyclohexane, 1,4-dioxane, fluorine-based solvents, and the like. Freeze-drying is performed inside a closed vacuum vessel.

Normal pressure drying evaporates the solvent contained inside the gel layer C under normal pressure. Since it is important to reduce the contraction force of the microskeleton of the gel layer C due to the capillary force accompanying solvent evaporation, solvents suitable for atmospheric drying include solvents with low surface tension, such as low molecular weight fats such as hexane and heptane. Group hydrocarbon-based solvents or fluorine-based solvents are used. Since normal pressure drying is performed at normal pressure, a sealed container is not required.

The solvent replacement is carried out at a temperature below the boiling point of the solvent in order to prevent the fine structure of the gel layer C from being damaged by the boiling of the solvent. However, the solvent may be heated at a temperature below the boiling point in order to increase the replacement efficiency of the solvent. The heating temperature is, for example, 40.degree. C. to 100.degree.

The number of solvent substitutions is one in the present embodiment, but may be multiple times. In other words, the solvent contained in the gel layer C may be replaced with the first solvent and then with the second solvent from the solvent of the raw material liquid.

When the compatibility between the solvent of the raw material liquid and the second solvent is low, the substitution efficiency becomes poor. can reduce the time required to replace As the first solvent, one having high compatibility with both the solvent of the raw material liquid and the second solvent is used.

In addition, when the solvent of the raw material liquid is suitable for drying, solvent replacement is unnecessary.

In drying (S6), the solvent contained inside the gel layer C is removed. As a method for drying the gel layer C, supercritical drying, freeze drying, or normal pressure drying is used as described above. Among these, normal pressure drying is superior in that it does not require a closed container.

Drying under normal pressure is carried out at a temperature below the boiling point of the solvent in order to prevent the fine structure of the gel layer C from being damaged by the boiling of the solvent. However, the gel layer C may be heated at a temperature below the boiling point in order to increase the solvent removal efficiency. The drying temperature of the gel layer C is, for example, room temperature to 100.degree.

In normal pressure drying, the evaporation of the solvent contained in the gel layer C can be accelerated by blowing air against the gel layer C. The solvent evaporated by normal pressure drying is recovered and discarded or recycled as necessary.

The gel layer C obtained after drying is a xerogel and a porous monolith.

Drying ( S<b>6 ) may be performed while the gel layer C is supported by the support plate 25 . In this case, if the support plate 25 has the through holes H, the solvent can be removed from the front and rear surfaces of the gel layer C.

Examples are described below. All of Examples 1-2 below are examples.

(Example 1)
In forming the raw material liquid layer (S1), first, a sol liquid, which is a raw material liquid, was prepared. Specifically, 60 g of vinylmethyldimethoxysilane (VMDMS; manufactured by Tokyo Chemical Industry Co., Ltd.) and 0.66 g of di-t-butyl peroxide (DTBP; manufactured by Tokyo Chemical Industry Co., Ltd.) as a polymerization initiator are added, and the inner tank is made of PTFE. The mixture was placed in a 100 ml SUS pressure-resistant container, and the container was sealed while the upper air layer was replaced with nitrogen. After maintaining the container in an oven at 120° C. for 48 hours, it was removed from the oven and cooled to room temperature to obtain a viscous transparent oligomeric liquid. 5 g of this transparent oligomer liquid and 20 g of benzyl alcohol were placed in a 50 ml glass vial and stirred with a magnetic stirrer for 10 minutes. 1.5 g of a 75 mol aqueous solution was added and stirred at room temperature for 3 minutes to prepare a sol solution. The density of this sol liquid was 1.0 g/cm ³ .

Next, the prepared sol liquid was dropped inside a cylindrical container made of polypropylene (PP) having a diameter of 50 mm. A base liquid layer having a thickness of 10 mm was previously formed inside the container. As the base liquid, a fluorine-based solvent (trade name: Fluorinert FC-43 by 3M Company) having a density of 1.88 g/cm ³ was used. The sol liquid was dropped from a dropper so as to spread over the entire liquid surface of the base liquid layer. As a result, a sol liquid layer having a thickness of 4 mm was obtained, and the entire outer circumference of the sol liquid layer was adhered to the entire inner circumference of the PP container.

In the thinning of the raw material liquid layer (S2), the sol liquid was sucked up from the sol liquid layer with a pipette so as not to disturb the liquid surface of the sol liquid layer, and the thickness of the sol liquid layer was reduced from 4 mm to 1 mm. During thinning, the entire outer circumference of the sol liquid layer adhered to the entire inner circumference of the PP container.

After that, when the same FC-43 as the base liquid was dropped from the top of the sol liquid layer with a thickness of 1 mm, the sol liquid layer was broken and the sol liquid gathered in one place. It was confirmed that layers were formed.

After that, the formation (S1) and thinning (S2) of the raw material liquid layer were performed again to obtain a sol liquid layer having a thickness of 1 mm.

In the gelation of the sol-liquid layer (S3), the lid of the PP container was closed and the PP container was placed in an oven at 80°C for 48 hours. Then it was taken out of the oven and cooled to room temperature, whereupon a gel layer floating on the base liquid layer was obtained. The thickness of the gel layer was 0.9 mm, the diameter of the gel layer was 45 mm smaller than the inner diameter of the PP container, and the entire outer periphery of the gel layer was separated from the entire inner periphery of the PP container. After that, the gel layer was taken out from the PP container.

In the gel layer solvent replacement (S5), the gel layer taken out of the PP container was immersed in 60° C. isopropyl alcohol (IPA) stored inside another container for 16 hours. After that, the IPA was replaced with a new one and immersed again in IPA at 60° C. for 16 hours, which was repeated three times. Subsequently, in order to replace the solvent inside the gel layer from IPA with heptane, the gel layer was immersed in heptane at 60° C. for 16 hours, which was repeated three times, and the heptane was replaced with new one twice during the immersion.

In the drying of the gel layer (S6), the gel layer after solvent replacement with heptane was dried under normal pressure at 60° C. for 10 hours. The dried gel layer was a transparent porous body with a thickness of 0.8 mm and a density of 0.2 g/cm ³ .

(Example 2)
In forming the raw material liquid layer (S1), first, a sol liquid, which is a raw material liquid, was prepared. Specifically, 30 g of 3-methacryloxypropyltrimethoxysilane (KBM-503; manufactured by Shin-Etsu Chemical Co., Ltd.), 30 g of ethanol, and 2,2′-azobis(2,4-dimethylvaleronitrile) as a polymerization initiator ( V65 (manufactured by Wako Pure Chemical Industries, Ltd.) (0.3 g) was put into a 100 ml SUS pressure-resistant container, and the container was sealed while the upper air layer was replaced with nitrogen. After maintaining this container in an oven at 80° C. for 24 hours, it was removed from the oven and cooled to room temperature to obtain a viscous transparent oligomeric liquid. 5 g of this transparent oligomer liquid and 20 g of benzyl alcohol were placed in a 50 ml glass vial and stirred with a magnetic stirrer for 10 minutes. In addition, the mixture was stirred at room temperature for 10 seconds to prepare a sol. The density of this sol liquid was 1.0 g/cm ³ .

Next, the prepared sol liquid was dropped inside a cylindrical container made of polypropylene (PP) having a diameter of 50 mm. A base liquid layer having a thickness of 10 mm was previously formed inside the container. As the base liquid, a fluorine-based solvent (trade name: Fluorinert FC-43 by 3M Company) having a density of 1.88 g/cm ³ was used. The sol liquid was dropped from a dropper so as to spread over the entire liquid surface of the base liquid layer. As a result, a sol liquid layer having a thickness of 4 mm was obtained, and the entire outer circumference of the sol liquid layer was adhered to the entire inner circumference of the PP container.

In the thinning of the raw material liquid layer (S2), the sol liquid was sucked up from the sol liquid layer with a pipette so as not to disturb the liquid surface of the sol liquid layer, and the thickness of the sol liquid layer was reduced from 4 mm to 1 mm. During thinning, the entire outer circumference of the sol liquid layer adhered to the entire inner circumference of the PP container.

After that, when the same FC-43 as the base liquid was dropped from the top of the sol liquid layer with a thickness of 1 mm, the sol liquid layer was broken and the sol liquid gathered in one place. It was confirmed that layers were formed.

After that, the formation (S1) and thinning (S2) of the raw material liquid layer were performed again to obtain a sol liquid layer having a thickness of 1 mm.

In the gelation of the sol-liquid layer (S3), the lid of the PP container was closed and the PP container was placed in an oven at 80°C for 48 hours. Then it was taken out of the oven and cooled to room temperature, whereupon a gel layer floating on the base liquid layer was obtained. The thickness of the gel layer was 0.8 mm, the diameter of the gel layer was 43 mm which was smaller than the inner diameter of the PP container, and the entire outer periphery of the gel layer was separated from the entire inner periphery of the PP container. After that, the gel layer was taken out from the PP container.

In the gel layer solvent replacement (S5), the gel layer taken out of the PP container was immersed in 60° C. isopropyl alcohol (IPA) stored inside another container for 16 hours. After that, the IPA was replaced with a new one and immersed again in IPA at 60° C. for 16 hours, which was repeated three times. Subsequently, in order to replace the solvent inside the gel layer from IPA with heptane, the gel layer was immersed in heptane at 60° C. for 16 hours, which was repeated three times, and the heptane was replaced with new one twice during the immersion.

In the drying of the gel layer (S6), the gel layer after solvent replacement with heptane was dried under normal pressure at 60° C. for 10 hours. The gel layer after drying was a transparent porous body with a thickness of 0.7 mm and a density of 0.6 g/cm ³ .

Although the gel manufacturing method and the gel manufacturing apparatus according to the present disclosure have been described above, the present disclosure is not limited to the above embodiments. Various changes, modifications, substitutions, additions, deletions, and combinations are possible within the scope of the claims. These also naturally belong to the technical scope of the present disclosure.

1 Manufacturing Apparatus 2 Storage Unit 21 Formwork 3 Raw Material Supply Unit 5 Raw Material Liquid Suction Unit 6 Gelation Promotion Unit A Raw Material Liquid Layer B Base Liquid Layer C Gel Layer

Claims (11)

supplying the raw material liquid of the gel onto the surface of the liquid whose outer periphery is surrounded by the mold of the base liquid layer having a density higher than that of the raw material liquid to form a raw material liquid layer in contact with the entire inner circumference of the mold;
discharging the raw material liquid from the raw material liquid layer after contacting the entire inner circumference of the mold to the outside of the mold, and thinning the raw material liquid layer to a thickness less than the equilibrium thickness;
gelling the thinned raw material liquid layer on the liquid surface of the base liquid layer;
Gel manufacturing method. 2. The method according to claim 1, wherein the suction port of a nozzle is set at the same height as the upper surface of the thinned raw material liquid layer, and the raw material liquid is discharged from the raw material liquid layer to the outside of the mold. 3. The method according to claim 1 or 2, wherein the base liquid layer is a liquid compound containing fluorine atoms. 4. The method according to any one of claims 1 to 3, wherein a gel layer obtained by gelling the raw material liquid layer is lifted from the base liquid layer. Before forming the raw material liquid layer on the liquid surface of the base liquid layer, when lifting the gel layer from the base liquid layer below the interface between the base liquid layer and the raw material liquid layer, the 5. The method according to claim 4, wherein a support plate is installed to support the gel layer from below. 6. The method according to any one of claims 1 to 5, wherein the solvent contained in the gel layer obtained by gelling the raw material liquid layer is replaced with another solvent. 7. The method according to any one of claims 1 to 6, wherein the solvent contained in the gel layer obtained by gelling the raw material liquid layer is removed. a formwork surrounding the periphery of the liquid surface of the base liquid layer having a higher density than the gel raw material liquid;
a raw material liquid supply unit that supplies the raw material liquid above the liquid surface surrounded by the mold and forms a raw material liquid layer in contact with the entire inner circumference of the mold;
a raw material suction part that discharges the raw material liquid from the raw material liquid layer that is in contact with the entire inner circumference of the mold to the outside of the mold and thins the raw material liquid layer to a thickness less than the equilibrium thickness;
a gelation promoting unit for gelling the thinned raw material liquid layer on the liquid surface of the base liquid layer;
A gel manufacturing apparatus. 9. The raw material liquid suction part according to claim 8, wherein the raw material liquid suction part includes a nozzle that discharges the raw material liquid from the raw material liquid layer to the outside of the mold at a position that is at the same height as the upper surface of the thinned raw material liquid layer. Device. A support plate is provided below the interface between the base liquid layer and the raw material liquid layer for supporting the gel layer from below when the gel layer obtained by gelling the raw material liquid layer is lifted from the base liquid layer. 10. Apparatus according to claim 8 or 9. 11. The device according to claim 10, wherein said support plate has a plurality of through holes penetrating through the front and back surfaces of said support plate at intervals in the direction of the main surface of said support plate.

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