WO2020012553A1 - Coating liquid and coating film - Google Patents
Coating liquid and coating film Download PDFInfo
- Publication number
- WO2020012553A1 WO2020012553A1 PCT/JP2018/026010 JP2018026010W WO2020012553A1 WO 2020012553 A1 WO2020012553 A1 WO 2020012553A1 JP 2018026010 W JP2018026010 W JP 2018026010W WO 2020012553 A1 WO2020012553 A1 WO 2020012553A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- resin
- group
- mass
- airgel
- coating liquid
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D201/00—Coating compositions based on unspecified macromolecular compounds
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
- C09D7/20—Diluents or solvents
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D7/00—Features of coating compositions, not provided for in group C09D5/00; Processes for incorporating ingredients in coating compositions
- C09D7/40—Additives
- C09D7/65—Additives macromolecular
Definitions
- the present invention relates to a coating liquid and a coating film.
- Aerogel is known as a material having excellent heat insulating properties and transparency.
- a method has been proposed in which aerogel having such properties is processed into particles and used as a constituent material of a heat insulating material (for example, Patent Document 1).
- Patent Literature 1 proposes using particulate aerogel as a filler between resin plates and the like constituting a heat insulating window.
- a configuration other than the airgel particles is indispensable as described above.
- the layer of the airgel particles can be formed directly on the surface of the object, the configuration can be made simpler, and the layer shape is hardly restricted by the surface shape of the object.
- the present invention has been made in view of the above circumstances, and has an object to provide a novel airgel particle-containing coating liquid. Another object of the present invention is to provide a coating film obtained by using the coating liquid.
- the present invention provides a coating liquid containing airgel particles, a binder resin and a liquid medium, wherein the content of the airgel particles is 20% by mass or more.
- a larger amount of airgel particles than in the prior art is present in a dispersed state. Therefore, a coating film containing airgel particles densely can be formed on the target surface.
- One reason that a large amount of airgel particles could be dispersed in the coating liquid is that the dispersion method was appropriately adjusted.
- the liquid medium can contain water.
- the liquid medium can further include an organic solvent.
- the binder resin is an epoxy resin, a silicone resin, a phenol resin, a urea resin, a melamine resin, a polyurethane resin, a polyethylene resin, a polypropylene resin, a polystyrene resin, a polyester resin, an acrylic resin, a polyvinyl chloride resin, At least one selected from the group consisting of vinyl acetate resin, polyamide resin, polyimide resin, cellulose resin, and polyvinyl resin can be included. Thereby, the film formability can be further improved.
- the specific gravity of the coating liquid of the present invention can be 0.8 or less.
- the present invention also provides a coating film containing airgel particles and a binder resin, wherein the content of the airgel particles is 80% by mass or more and the density is 0.4 g / cm 3 or less.
- a light coating film (aerogel coating film) in which airgel particles are highly filled as described above.
- this can be realized by using the coating liquid of the present invention.
- the binder resin is an epoxy resin, silicone resin, phenol resin, urea resin, melamine resin, polyurethane resin, polyethylene resin, polypropylene resin, polystyrene resin, polyester resin, acrylic resin, polyvinyl chloride resin, poly At least one selected from the group consisting of vinyl acetate resin, polyamide resin, polyimide resin, cellulose resin, and polyvinyl resin can be included. Thereby, the film quality can be further improved.
- a novel airgel particle-containing coating liquid can be provided. Further, according to the present invention, a coating film (airgel coating film) obtained by using the coating liquid can be provided.
- a numerical range indicated by using “to” indicates a range including numerical values described before and after “to” as a minimum value and a maximum value, respectively.
- “A or B” may include any one of A and B, and may include both.
- the materials exemplified in the present embodiment can be used alone or in combination of two or more, unless otherwise specified.
- a dry gel obtained by using a supercritical drying method for a wet gel is aerogel
- a dry gel obtained by drying under atmospheric pressure is a xerogel
- a dry gel obtained by freeze-drying is a cryogel.
- the obtained low-density dried gel is referred to as “aerogel” regardless of the method for drying the wet gel. That is, in the present embodiment, “aerogel” is a broadly defined aerogel, “Gel-complied of a microporous solid in which the dispersed phase is a gas (a gel composed of a microporous solid whose dispersed phase is a gas). Means.
- the inside of the airgel has a network-like fine structure, and has a cluster structure in which a particulate airgel component of about 2 to 20 nm is bonded. There are pores smaller than 100 nm between the skeletons formed by the clusters. Thereby, the airgel has a three-dimensionally fine porous structure.
- the aerogel according to the present embodiment is, for example, a silica aerogel containing silica as a main component.
- the silica airgel include a so-called organic-inorganic hybridized silica airgel into which an organic group (eg, a methyl group) or an organic chain is introduced.
- the airgel particles in the present embodiment are not particularly limited, and airgel particles manufactured by various known manufacturing methods can be used.
- an airgel that can constitute the airgel particles of the present embodiment will be described.
- the airgel is selected from the group consisting of a silicon compound having a hydrolyzable functional group or a condensable functional group, and a hydrolysis product of a silicon compound having a hydrolyzable functional group, as described below. It is a dried product of a wet gel which is a condensate of a sol containing at least one (a product obtained by drying a wet gel generated from a sol: a dried product of a wet gel derived from a sol).
- the airgel according to the present embodiment can have a structure represented by the following general formula (1).
- the airgel according to the present embodiment can have a structure represented by the following general formula (1a) as a structure including the structure represented by the formula (1).
- R 1 and R 2 each independently represent an alkyl group or an aryl group
- R 3 and R 4 each independently represent an alkylene group.
- examples of the aryl group include a phenyl group and a substituted phenyl group.
- examples of the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group.
- p represents an integer of 1 to 50.
- two or more R 1 may be the same or different, and similarly, two or more R 2 may be the same or different.
- two R 3 may be the same or different, and similarly, two R 4 may be the same or different.
- R 1 and R 2 each independently include an alkyl group having 1 to 6 carbon atoms, a phenyl group, and the like. And the like.
- R 3 and R 4 each independently include an alkylene group having 1 to 6 carbon atoms, and the alkylene group includes an ethylene group, a propylene group, and the like.
- p may be 2 to 30, and may be 5 to 20.
- the aerogel according to the present embodiment also has a ladder-type structure including a support portion and a bridge portion, and the bridge portion may have a structure represented by the following general formula (2).
- the “ladder type structure” refers to a structure having two struts and bridges connecting the struts (bridges) (having a so-called “ladder” form). It is.
- the skeleton of the airgel may have a ladder-type structure, but the airgel may have a ladder-type structure partially.
- R 5 and R 6 each independently represent an alkyl group or an aryl group, and b represents an integer of 1 to 50.
- examples of the aryl group include a phenyl group and a substituted phenyl group.
- examples of the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group.
- b is an integer of 2 or more
- two or more R 5 may be the same or different, and similarly, two or more R 6 may be the same. May also be different.
- silsesquioxane is a polysiloxane having a composition formula: (RSiO 1.5 ) n , and can have various skeleton structures such as a cage type, a ladder type, and a random type.
- the structure of the crosslinked portion is -O-, but the aerogel according to the present embodiment
- the structure of the crosslinked portion is a structure (polysiloxane structure) represented by the above general formula (2).
- the airgel of this embodiment may have a structure derived from silsesquioxane in addition to the structure represented by the general formula (2).
- R represents a hydroxy group, an alkyl group or an aryl group.
- the ladder-type structure has the following general formula ( It may have a ladder structure represented by 3).
- R 5 , R 6 , R 7 and R 8 each independently represent an alkyl group or an aryl group
- a and c each independently represent an integer of 1 to 3000
- b represents 1 to 50 Indicates an integer.
- examples of the aryl group include a phenyl group and a substituted phenyl group.
- the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group.
- b is an integer of 2 or more
- two or more R 5 may be the same or different
- two or more R 6 may be the same. May also be different.
- a is an integer of 2 or more
- two or more R 7 may be the same or different
- similarly, when c is an integer of 2 or more, two or more R 8 may be the same or different.
- R 5 , R 6 , R 7 and R 8 in the formulas (2) and (3) (where R 7 and R 8 are only in the formula (3))
- a and c can each independently be 6 to 2000, but may be 10 to 1000.
- b may be 2 to 30, but may be 5 to 20.
- the structure represented by the following general formulas (4) to (6) can be introduced into the skeleton of the airgel.
- the airgel according to the present embodiment can have one of these structures alone or two or more of them.
- R 9 represents an alkyl group.
- examples of the alkyl group include an alkyl group having 1 to 6 carbon atoms, and examples of the alkyl group include a methyl group.
- R 10 and R 11 each independently represent an alkyl group.
- examples of the alkyl group include an alkyl group having 1 to 6 carbon atoms, and examples of the alkyl group include a methyl group.
- R 12 represents an alkylene group.
- examples of the alkylene group include an alkylene group having 1 to 10 carbon atoms, and examples of the alkylene group include an ethylene group and a hexylene group.
- the airgel according to the present embodiment may further contain silica particles in addition to the airgel component from the viewpoint of further toughening and achieving even better heat insulation and flexibility.
- An airgel containing an airgel component and silica particles can also be referred to as an airgel composite.
- the airgel composite has a cluster structure, which is a characteristic of aerogel, even though the airgel component and silica particles are composited, and is considered to have a three-dimensionally fine porous structure. .
- the airgel containing the airgel component and the silica particles is a silicon compound having a hydrolyzable functional group or a condensable functional group, and hydrolysis of a silicon compound having a hydrolyzable functional group.
- the product is a dried product of a wet gel that is a condensate of a sol containing at least one selected from the group consisting of products and silica particles.
- the silica particles can be used without any particular limitation, and include amorphous silica particles and the like.
- amorphous silica particles include fused silica particles, fumed silica particles, and colloidal silica particles.
- the colloidal silica particles have high monodispersity and easily suppress aggregation in the sol.
- the silica particles may have a hollow structure, a porous structure, or the like.
- the shape of the silica particles is not particularly limited, and examples thereof include a spherical shape, a cocoon shape, and an association type. Among them, the use of spherical particles as the silica particles makes it easier to suppress aggregation in the sol.
- the average primary particle diameter of the silica particles is 1 nm or more, or 5 nm or more, from the viewpoint that it is easy to impart appropriate strength and flexibility to the aerogel, and to easily obtain an aerogel having excellent resistance to shrinkage during drying. And may be 20 nm or more.
- the average primary particle diameter of the silica particles is 500 nm or less, 300 nm or less, and 100 nm or less, from the viewpoint of easily suppressing the solid heat conduction of the silica particles and easily obtaining an aerogel having excellent heat insulating properties.
- the following may be used. From these viewpoints, the average primary particle diameter of the silica particles may be 1 to 500 nm, 5 to 300 nm, or 20 to 100 nm.
- the average particle diameter of the airgel component and the average primary particle diameter of the silica particles can be obtained by directly observing the airgel using a scanning electron microscope (hereinafter abbreviated as “SEM”).
- SEM scanning electron microscope
- the “diameter” here means a diameter when a cross section of the particles exposed on the cross section of the airgel is regarded as a circle.
- the “diameter when the cross section is regarded as a circle” is the diameter of the true circle when the area of the cross section is replaced by a perfect circle having the same area.
- the diameter of a circle is determined for 100 particles, and the average is taken.
- the average particle size of the silica particles can also be measured from the raw material.
- the biaxial average primary particle diameter is calculated as follows from the result of observing 20 arbitrary particles by SEM. That is, taking colloidal silica particles having a solid concentration of about 5 to 40% by mass and dispersed in water as an example, a dispersion liquid of colloidal silica particles was obtained by cutting a wafer with patterned wiring into 2 cm square. After soaking the chip for about 30 seconds, the chip is rinsed with pure water for about 30 seconds and dried with nitrogen blow. Thereafter, the chip is placed on a sample stage for SEM observation, an acceleration voltage of 10 kV is applied, and the silica particles are observed at a magnification of 100,000 and an image is taken. 20 silica particles are arbitrarily selected from the obtained image, and the average of the particle diameters of the particles is defined as the average particle diameter.
- the number of silanol groups per 1 g of the silica particles may be 10 ⁇ 10 18 / g or more, and may be 50 ⁇ 10 18 / g or more from the viewpoint of easily obtaining an aerogel having excellent shrink resistance. , 100 ⁇ 10 18 / g or more.
- the number of silanol groups per gram of the silica particles may be 1000 ⁇ 10 18 / g or less, 800 ⁇ 10 18 / g or less, and 700 ⁇ It may be 10 18 / g or less.
- the number of silanol groups per 1 g of the silica particles may be 10 ⁇ 10 18 to 1000 ⁇ 10 18 / g, or may be 50 ⁇ 10 18 to 800 ⁇ 10 18 / g. , 100 ⁇ 10 18 to 700 ⁇ 10 18 particles / g.
- the specific surface area of the airgel particles can be 1200 m 2 / g or less, but may be 1000 m 2 / g or less, 900 m 2 / g or less, or 800 m 2 / g or less. . This makes it easy to prepare a coating liquid having excellent film-forming properties.
- the lower limit of the specific surface area of the airgel particles is not particularly limited, but may be about 30 m 2 / g from the viewpoint of suppressing aggregation in the coating liquid and improving the filling rate.
- the specific surface area can be measured by the BET method.
- a gas adsorption amount measuring device Autosorb-iQ (Autosorb is a registered trademark) manufactured by Kantachrome Instruments Japan GK
- Autosorb-iQ Autosorb is a registered trademark manufactured by Kantachrome Instruments Japan GK
- the average particle diameter D50 of the airgel particles may be 1 to 1000 ⁇ m, but may be 3 to 700 ⁇ m, 5 to 500 ⁇ m, 10 to 100 ⁇ m, or 10 to 50 ⁇ m. You may. When the average particle diameter D50 of the airgel particles is 1 ⁇ m or more, it becomes easy to obtain airgel particles excellent in dispersibility, handleability, and the like. On the other hand, when the average particle diameter D50 is 1000 ⁇ m or less, airgel particles having excellent dispersibility can be easily obtained.
- the average particle size of the airgel particles can be appropriately adjusted by a pulverizing method and pulverizing conditions, a sieving method, a classification method, and the like.
- the average particle diameter D50 of the airgel particles can be measured by a laser diffraction / scattering method.
- the airgel particles are added to a solvent (ethanol) so that the content of the airgel particles becomes 0.05 to 5% by mass, and the airgel particles are dispersed by vibrating for 15 to 30 minutes with a 50 W ultrasonic homogenizer. Thereafter, about 10 mL of the dispersion is injected into a laser diffraction / scattering type particle size distribution analyzer, and the particle size is measured at 25 ° C. with a refractive index of 1.3 and an absorption of 0.
- the particle diameter at an integrated value of 50% (by volume) in the particle diameter distribution is defined as an average particle diameter D50.
- the measuring device for example, Microtrac MT3000 (product name, manufactured by Nikkiso Co., Ltd.) can be used.
- the method for producing the airgel particles is not particularly limited, but for example, it can be produced by the following method.
- the airgel particles of the present embodiment are formed by a sol generation step, a sol obtained in the sol generation step, and a wet gel generation step of aging to obtain a wet gel, and a wet gel obtained in the wet gel generation step.
- a manufacturing method mainly comprising a washing and solvent replacement step of washing and (if necessary) solvent replacement, a drying step of drying the washed and solvent-replaced wet gel, and a pulverization step of pulverizing the aerogel obtained by drying. Can be manufactured.
- a sol generating step, a wet gel generating step, a wet gel crushing step of crushing the wet gel obtained in the wet gel generating step, a washing and solvent replacement step, and a manufacturing method mainly comprising a drying step May be.
- the size of the obtained airgel particles can be further uniformed by sieving, classification and the like. By adjusting the size of the particles, the dispersibility can be increased.
- the “sol” is a state before a gelation reaction occurs, and in the present embodiment, means a state in which, for example, a silicon compound and optionally silica particles are dissolved or dispersed in a solvent. I do.
- the wet gel refers to a gel solid in a wet state that does not have fluidity while containing a liquid medium.
- the sol generation step is a step of mixing a silicon compound and, in some cases, silica particles (may be a solvent containing silica particles) in a solvent and performing a hydrolysis reaction as necessary. More specifically, the sol generation step includes a hydrolysis of a silicon compound having a hydrolyzable functional group, a silicon compound having a condensable functional group, and a silicon compound having a hydrolyzable functional group. This is a step of producing a sol containing a product or the like.
- the sol generation step includes a silicon compound having a hydrolyzable functional group or a condensable functional group, and at least one selected from the group consisting of hydrolysis products of the silicon compound having a hydrolyzable functional group. It can be said that this is a step of producing a sol to be contained.
- the aerogel exemplified above can be obtained by drying a wet gel generated from such a sol.
- a polysiloxane compound can be used as the silicon compound. That is, the sol is at least selected from the group consisting of a polysiloxane compound having a hydrolyzable functional group or a condensable functional group, and a hydrolysis product of a polysiloxane compound having a hydrolyzable functional group.
- a polysiloxane compound group One kind of compound (hereinafter, sometimes referred to as “polysiloxane compound group”) may be contained.
- the functional group in the polysiloxane compound is not particularly limited, but may be a group that reacts with the same functional group or a group that reacts with another functional group.
- Examples of the hydrolyzable functional group include an alkoxy group.
- Examples of the condensable functional group include a hydroxyl group, a silanol group, a carboxyl group, and a phenolic hydroxyl group.
- the hydroxyl group may be contained in a hydroxyl group-containing group such as a hydroxyalkyl group.
- a polysiloxane compound having a hydrolyzable functional group or a condensable functional group is a reactive group different from the hydrolyzable functional group and the condensable functional group (the hydrolyzable functional group and the condensable functional group).
- the reactive group include an epoxy group, a mercapto group, a glycidoxy group, a vinyl group, an acryloyl group, a methacryloyl group, and an amino group.
- the epoxy group may be contained in an epoxy group-containing group such as a glycidoxy group.
- groups that improve the flexibility of the airgel include alkoxy groups, silanol groups, hydroxyalkyl groups, and the like.
- alkoxy groups and hydroxyalkyl groups are:
- the compatibility of the sol can be further improved.
- the number of carbon atoms of the alkoxy group and the hydroxyalkyl group can be 1 to 6, but the flexibility of the aerogel is further improved. From the viewpoint, it may be 2 to 4.
- Examples of the polysiloxane compound having a hydroxyalkyl group in the molecule include those having a structure represented by the following general formula (A).
- A a polysiloxane compound having a structure represented by the following general formula (A)
- the structures represented by the general formulas (1) and (1a) can be introduced into the skeleton of the airgel.
- R 1a represents a hydroxyalkyl group
- R 2a represents an alkylene group
- R 3a and R 4a each independently represent an alkyl group or an aryl group
- n represents an integer of 1 to 50.
- examples of the aryl group include a phenyl group and a substituted phenyl group.
- the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group.
- two R 1a may be the same or different, and similarly, two R 2a may be the same or different.
- two or more R 3a may be the same or different, and similarly, two or more R 4a may be the same or different.
- R 1a includes a hydroxyalkyl group having 1 to 6 carbon atoms and the like, and the hydroxyalkyl group includes a hydroxyethyl group and a hydroxypropyl group.
- R 2a includes an alkylene group having 1 to 6 carbon atoms, and the alkylene group includes an ethylene group, a propylene group, and the like.
- R 3a and R 4a each independently include an alkyl group having 1 to 6 carbon atoms, a phenyl group and the like, and the alkyl group includes a methyl group and the like.
- n can be 2 to 30, but may be 5 to 20.
- polysiloxane compound having the structure represented by the general formula (A) commercially available products can be used, and compounds such as X-22-160AS, KF-6001, KF-6002, and KF-6003 (all of which are shown below) can be used. And Shin-Etsu Chemical Co., Ltd.), and compounds such as XF42-B0970 and Fluid ⁇ OFOH ⁇ 702-4% (all manufactured by Momentive Performance Materials Japan GK).
- Examples of the polysiloxane compound having an alkoxy group in a molecule include those having a structure represented by the following general formula (B).
- a polysiloxane compound having a structure represented by the following general formula (B) By using a polysiloxane compound having a structure represented by the following general formula (B), a ladder-type structure having a crosslinked portion represented by the general formula (2) or (3) is introduced into the skeleton of the airgel. can do.
- R 1b represents an alkyl group, an alkoxy group or an aryl group
- R 2b and R 3b each independently represent an alkoxy group
- R 4b and R 5b each independently represent an alkyl group or an aryl group.
- M represents an integer of 1 to 50.
- examples of the aryl group include a phenyl group and a substituted phenyl group.
- the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group.
- two R 1b may be the same or different
- two R 2b may be the same or different, respectively.
- 3b may be the same or different.
- when m is an integer of 2 or more
- two or more R 4b may be the same or different, and similarly, two or more R 5b may be the same. May also be different.
- R 1b includes an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and the like, and the alkyl group or the alkoxy group is a methyl group. Methoxy group, ethoxy group and the like.
- R 2b and R 3b each independently include an alkoxy group having 1 to 6 carbon atoms, and the alkoxy group includes a methoxy group and an ethoxy group.
- R 4b and R 5b each independently include an alkyl group having 1 to 6 carbon atoms, a phenyl group and the like, and the alkyl group includes a methyl group and the like.
- m can be 2 to 30, but may be 5 to 20.
- the polysiloxane compound having the structure represented by the general formula (B) can be obtained by appropriately referring to the production methods reported in JP-A-2000-26609, JP-A-2012-233110, and the like. .
- the polysiloxane compound having the alkoxy group may be present as a hydrolysis product in the sol, and the polysiloxane compound having the alkoxy group and the hydrolysis product are mixed. May be.
- the polysiloxane compound having an alkoxy group all of the alkoxy groups in the molecule may be hydrolyzed or partially hydrolyzed.
- polysiloxane compounds having a hydrolyzable functional group or a condensable functional group, and hydrolysis products of a polysiloxane compound having a hydrolyzable functional group may be used alone or as a mixture of two or more. May be used.
- a silicon compound other than the above-described polysiloxane compound can be used as the silicon compound.
- Such silicon compounds include silane monomers. That is, the sol containing the silicon compound is a group consisting of a silane monomer having a hydrolyzable functional group or a condensable functional group, and a hydrolysis product of the silane monomer having a hydrolyzable functional group. At least one selected from the following (hereinafter sometimes referred to as “silane monomer group”) may be contained in addition to the above-mentioned polysiloxane compound group or in place of the above-mentioned polysiloxane compound group.
- the number of silicon atoms in the molecule of the silane monomer can be 1 to 6.
- the silane monomer having a hydrolyzable functional group is not particularly limited, and examples thereof include an alkyl silicon alkoxide.
- Alkyl silicon alkoxides can reduce the number of hydrolyzable functional groups to three or less from the viewpoint of improving water resistance.
- Examples of such an alkyl silicon alkoxide include monoalkyl trialkoxy silane, monoalkyl dialkoxy silane, dialkyl dialkoxy silane, monoalkyl monoalkoxy silane, dialkyl monoalkoxy silane, and trialkyl monoalkoxy silane.
- Examples thereof include methyltrimethoxysilane, methyldimethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane and the like.
- examples of the hydrolyzable functional group include an alkoxy group such as a methoxy group and an ethoxy group.
- the silane monomer having a condensable functional group is not particularly limited, but includes silanetetraol, methylsilanetriol, dimethylsilanediol, phenylsilanetriol, phenylmethylsilanediol, diphenylsilanediol, n-propylsilanetriol, hexylsilane Triol, octylsilanetriol, decylsilanetriol, trifluoropropylsilanetriol and the like can be mentioned.
- silane monomer further has the above-mentioned reactive group (functional group which does not correspond to the hydrolyzable functional group and the condensable functional group) different from the hydrolyzable functional group and the condensable functional group, Good.
- silane monomer having a hydrolyzable functional group and a reactive group examples include vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-2- (Aminoethyl) -3-aminopropylmethyldimethoxysilane and the like can also be used.
- silane monomers having a condensable functional group and a reactive group examples include vinyl silane triol, 3-glycidoxypropyl silane triol, 3-glycidoxy propyl methyl silane diol, 3-methacryloxy propyl silane triol, and 3-methacryloxy propyl Methylsilanediol, 3-acryloxypropylsilanetriol, 3-mercaptopropylsilanetriol, 3-mercaptopropylmethylsilanediol, N-phenyl-3-aminopropylsilanetriol, N-2- (aminoethyl) -3-amino Propylmethylsilanediol and the like can also be used.
- the silane monomer may have two or more silicon atoms, and bistrimethoxysilylmethane, bistrimethoxysilylethane, bistrimethoxysilylhexane and the like can also be used.
- a silane monomer having a hydrolyzable functional group or a condensable functional group, and a hydrolysis product of the silane monomer having a hydrolyzable functional group may be used alone or as a mixture of two or more. Is also good.
- the sol generation step is a silicon compound having a hydrolyzable functional group or a condensable functional group, and a hydrolysis product of a silicon compound having a hydrolyzable functional group. It can be said that this is a step of generating a sol containing at least one selected from the group and silica particles.
- the content of the polysiloxane compound group contained in the sol (the content of the polysiloxane compound having a hydrolyzable functional group or a condensable functional group, and the hydrolysis of the polysiloxane compound having a hydrolyzable functional group)
- the sum of the contents of the products may be 5 parts by mass or more, or 10 parts by mass or more with respect to 100 parts by mass of the total amount of the sol, from the viewpoint of more easily obtaining good reactivity.
- the content of the polysiloxane compound group contained in the sol may be 50 parts by mass or less with respect to 100 parts by mass of the total amount of the sol, from the viewpoint of making it easier to obtain good compatibility. There may be. From these viewpoints, the content of the polysiloxane compound group contained in the sol may be 5 to 50 parts by mass or 10 to 30 parts by mass based on 100 parts by mass of the total amount of the sol.
- the content of the silane monomer group (the content of the silane monomer having a hydrolyzable functional group or a condensable functional group, and the content of the silane monomer having a hydrolyzable functional group)
- the sum of the contents of the hydrolysis products may be 5 parts by mass or more, or 10 parts by mass or more with respect to 100 parts by mass of the total amount of the sol, from the viewpoint of further obtaining good reactivity. Is also good.
- the content of the silane monomer group contained in the sol may be 50 parts by mass or less, or 30 parts by mass or less, based on 100 parts by mass of the total amount of the sol, from the viewpoint of further obtaining good compatibility. May be. From these viewpoints, the content of the silane monomer group contained in the sol may be 5 to 50 parts by mass, or may be 10 to 30 parts by mass.
- the ratio between the content of the polysiloxane compound group and the content of the silane monomer group is preferably 1: from the viewpoint that good compatibility is more easily obtained. It may be 0.5 or more, or 1: 1 or more.
- the ratio between the content of the polysiloxane compound group and the content of the silane monomer group may be 1: 4 or less, or 1: 2 or less, from the viewpoint of further suppressing gel shrinkage. Good. From these viewpoints, the ratio of the content of the polysiloxane compound group to the content of the silane monomer group may be from 1: 0.5 to 1: 4, and may be from 1: 1 to 1: 2. Is also good.
- the content of the silica particles makes it easy to impart appropriate strength to the aerogel, and from the viewpoint of easily obtaining an aerogel having excellent shrink resistance during drying, the total amount of the sol is 100 parts by mass. On the other hand, it may be 1 part by mass or more, or 4 parts by mass or more.
- the content of the silica particles is easy to suppress the solid heat conduction of the silica particles, and from the viewpoint of easily obtaining an aerogel having excellent heat insulating properties, the total amount of the sol may be 20 parts by mass or less based on 100 parts by mass of the sol, It may be 15 parts by mass or less. From these viewpoints, the content of the silica particles may be 1 to 20 parts by mass or 4 to 15 parts by mass with respect to 100 parts by mass of the total amount of the sol.
- a solvent is used for mixing and possibly hydrolyzing the silicon compound.
- the solvent for example, water or a mixture of water and alcohol can be used.
- the alcohol include methanol, ethanol, n-propanol, 2-propanol, n-butanol, 2-butanol, t-butanol and the like.
- examples of the alcohol having a low surface tension and a low boiling point in terms of reducing the interfacial tension with the gel wall include methanol, ethanol, and 2-propanol. These may be used alone or as a mixture of two or more.
- the amount of the alcohol when used as the solvent, can be 4 to 8 mol, or 4 to 6.5 mol per 1 mol of the total amount of the polysiloxane compound group and the silane monomer group. Alternatively, it may be 4.5 to 6 mol.
- the amount of the alcohol By setting the amount of the alcohol to 4 mol or more, it becomes easier to obtain good compatibility, and to set the amount to 8 mol or less, the shrinkage of the gel is more easily suppressed.
- the solvent may contain an acid catalyst for promoting the hydrolysis reaction.
- the acid catalyst include inorganic acids such as hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid, hypophosphorous acid, bromic acid, chloric acid, chlorous acid, and hypochlorous acid; Acid phosphates such as aluminum, magnesium acid phosphate and zinc acid phosphate; organic carboxylic acids such as acetic acid, formic acid, propionic acid, oxalic acid, malonic acid, succinic acid, citric acid, malic acid, adipic acid and azelaic acid And the like.
- an organic carboxylic acid is mentioned as an acid catalyst for further improving the water resistance of the obtained airgel.
- the organic carboxylic acid include acetic acid, and may be formic acid, propionic acid, oxalic acid, malonic acid, and the like. These may be used alone or as a mixture of two or more.
- the amount of the acid catalyst can be 0.001 to 0.1 part by mass based on 100 parts by mass of the total of the polysiloxane compound group and the silane monomer group.
- a surfactant as disclosed in Japanese Patent No. 5250900, a surfactant, a thermally hydrolyzable compound, and the like can be added to a solvent.
- a nonionic surfactant As the surfactant, a nonionic surfactant, an ionic surfactant or the like can be used. These may be used alone or as a mixture of two or more.
- a compound containing a hydrophilic part such as polyoxyethylene and a hydrophobic part mainly composed of an alkyl group a compound containing a hydrophilic part such as polyoxypropylene and the like can be used.
- the compound containing a hydrophilic part such as polyoxyethylene and a hydrophobic part mainly composed of an alkyl group include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene alkyl ether and the like.
- the compound containing a hydrophilic portion, such as polyoxypropylene include polyoxypropylene alkyl ether, a block copolymer of polyoxyethylene and polyoxypropylene, and the like.
- Examples of the ionic surfactant include a cationic surfactant, an anionic surfactant, and an amphoteric surfactant.
- Examples of the cationic surfactant include cetyltrimethylammonium bromide and cetyltrimethylammonium chloride, and examples of the anionic surfactant include sodium dodecylsulfonate.
- examples of the amphoteric surfactant include an amino acid-based surfactant, a betaine-based surfactant, and an amine oxide-based surfactant.
- Examples of the amino acid surfactant include acylglutamic acid and the like.
- Examples of the betaine-based surfactant include betaine lauryldimethylaminoacetate and betaine stearyldimethylaminoacetate.
- Examples of the amine oxide-based surfactant include lauryl dimethylamine oxide.
- surfactants have the effect of reducing the difference in chemical affinity between the solvent in the reaction system and the growing siloxane polymer in the wet gel formation step described below, and suppressing phase separation. It is believed that.
- the amount of the surfactant added depends on the type of the surfactant or the type and amount of the silicon compound. For example, 1 to 100 parts by mass relative to 100 parts by mass of the total of the polysiloxane compound group and the silane monomer group. It can be. Incidentally, the addition amount may be 5 to 60 parts by mass.
- thermohydrolyzable compound generates a basic catalyst by thermal hydrolysis, makes the reaction solution basic, and promotes the sol-gel reaction in the wet gel formation step described later.
- the thermohydrolyzable compound is not particularly limited as long as it can make the reaction solution basic after hydrolysis, and urea; formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N Acid amides such as -methylacetamide and N, N-dimethylacetamide; and cyclic nitrogen compounds such as hexamethylenetetramine.
- urea is particularly easy to obtain the above-mentioned promoting effect.
- the amount of the thermally hydrolyzable compound to be added is not particularly limited as long as it can sufficiently promote the sol-gel reaction in the wet gel forming step described below.
- the amount of addition can be 1 to 200 parts by mass based on 100 parts by mass of the total of the polysiloxane compound group and the silane monomer group.
- the amount may be 2 to 150 parts by mass.
- components such as carbon graphite, an aluminum compound, a magnesium compound, a silver compound, and a titanium compound may be added to a solvent for the purpose of suppressing heat radiation.
- the hydrolysis in the sol generation step depends on the type and amount of the silicon compound, silica particles, acid catalyst, surfactant and the like in the mixed solution, but for example, in a temperature environment of 20 to 60 ° C. for 10 minutes to 24 hours.
- the heat treatment may be performed for a period of time, or for 5 minutes to 8 hours in a temperature environment of 50 to 60 ° C.
- the temperature environment of the sol generation step may be adjusted to a temperature at which the hydrolysis of the heat-hydrolyzable compound is suppressed and the gelation of the sol is suppressed.
- the temperature at this time may be any temperature as long as it can suppress hydrolysis of the thermally hydrolyzable compound.
- the temperature environment in the sol generation step can be 0 to 40 ° C., but may be 10 to 30 ° C.
- the wet gel generation step is a step of gelling the sol obtained in the sol generation step and then aging to obtain a wet gel.
- a base catalyst can be used to promote gelation.
- the base catalyst examples include carbonates such as calcium carbonate, potassium carbonate, sodium carbonate, barium carbonate, magnesium carbonate, lithium carbonate, ammonium carbonate, copper (II) carbonate, iron (II) carbonate and silver (I) carbonate; hydrogen carbonate Hydrogen carbonates such as calcium, potassium hydrogen carbonate, sodium hydrogen carbonate and ammonium hydrogen carbonate; alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide and cesium hydroxide; ammonium hydroxide, ammonium fluoride; Ammonium compounds such as ammonium chloride and ammonium bromide; basic sodium phosphates such as sodium metaphosphate, sodium pyrophosphate and sodium polyphosphate; allylamine, diallylamine, triallylamine, isopropylamine, diisopropylamine, ethylamine, diethylamine Ruamine, triethylamine, 2-ethylhexylamine, 3-ethoxypropylamine, diiso
- ammonium hydroxide (aqueous ammonia) is excellent in that it has high volatility and hardly remains in the airgel particles after drying, so that it does not easily impair water resistance, and furthermore, it is economical.
- the above base catalysts may be used alone or in combination of two or more.
- a base catalyst By using a base catalyst, a dehydration condensation reaction or a dealcoholization condensation reaction of the silicon compound and silica particles in the sol can be promoted, and the sol can be gelled in a shorter time. In addition, thereby, a wet gel having higher strength (rigidity) can be obtained.
- ammonia has high volatility and hardly remains in the airgel particles. Therefore, by using ammonia as the base catalyst, airgel particles having more excellent water resistance can be obtained.
- the amount of the base catalyst added can be 0.5 to 5 parts by mass, or 1 to 4 parts by mass, based on 100 parts by mass of the total of the polysiloxane compound group and the silane monomer group.
- the amount is 0.5 parts by mass or more, gelation can be performed in a shorter time, and when the amount is 5 parts by mass or less, a decrease in water resistance can be further suppressed.
- the gelation of the sol in the wet gel formation step may be performed in a closed container so that the solvent and the base catalyst do not volatilize.
- the gelling temperature can be between 30 and 90 ° C, but may be between 40 and 80 ° C. By setting the gelation temperature to 30 ° C. or higher, gelation can be performed in a shorter time, and a wet gel having higher strength (rigidity) can be obtained. Further, by setting the gelling temperature to 90 ° C. or lower, the volatilization of the solvent (particularly, alcohol) is easily suppressed, so that gelation can be performed while suppressing volume shrinkage.
- the aging in the wet gel forming step may be performed in a closed container so that the solvent and the base catalyst do not volatilize.
- the aging strengthens the binding of the components constituting the wet gel, and as a result, a wet gel having high strength (rigidity) enough to suppress shrinkage during drying can be obtained.
- the aging temperature can be 30 to 90 ° C, but may be 40 to 80 ° C. By setting the aging temperature to 30 ° C. or higher, a wet gel having higher strength (rigidity) can be obtained, and by setting the aging temperature to 90 ° C. or lower, the volatilization of the solvent (particularly alcohol) is easily suppressed. Gelation can be performed while suppressing volume shrinkage.
- the gelation of the sol and the subsequent aging may be performed continuously in a series of operations.
- the gelation time and the aging time can be appropriately set according to the gelation temperature and the aging temperature.
- the gelation time can be particularly shortened as compared with the case where silica particles are not contained. This is presumed to be because the silanol group or the reactive group of the silicon compound in the sol forms a hydrogen bond or a chemical bond with the silanol group of the silica particles.
- the gelation time can be 10 to 120 minutes, but may be 20 to 90 minutes. By setting the gelling time to 10 minutes or more, it becomes easy to obtain a uniform wet gel, and by setting the gelling time to 120 minutes or less, the washing and solvent replacement steps to be described later can be simplified from the drying step.
- the total time of the gelation time and the aging time in the entire gelation and aging step can be 4 to 480 hours, but may be 6 to 120 hours.
- the total of the gelation time and the aging time can be 4 to 480 hours, but may be 6 to 120 hours.
- the wet gel obtained in the wet gel generating step is pulverized.
- the pulverization can be performed, for example, by putting the wet gel in a Henshall type mixer, or by performing a wet gel generation step in the mixer, and operating the mixer under appropriate conditions (number of rotations and time).
- a wet gel is placed in a sealable container, or a wet gel generation step is performed in a sealable container, and shaking is performed by using a shaking device or the like for an appropriate time.
- the particle size of the wet gel can be adjusted using a jet mill, a roller mill, a bead mill, or the like, if necessary.
- the washing and solvent replacement step includes a step of washing the wet gel obtained in the wet gel generation step or the wet gel pulverizing step (washing step) and a step of washing the washing liquid in the wet gel with a solvent suitable for drying conditions (a drying step described later).
- a solvent replacement step can be performed in a form in which only the solvent replacement step is performed without performing the step of washing the wet gel, but it is possible to reduce impurities such as unreacted substances and by-products in the wet gel.
- the wet gel may be washed from the viewpoint of enabling the production of highly pure airgel particles.
- the wet gel obtained in the wet gel forming step or the wet gel pulverizing step is washed.
- the washing can be repeatedly performed using, for example, water or an organic solvent. At this time, the cleaning efficiency can be improved by heating.
- organic solvent examples include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetone, methyl ethyl ketone, 1,2-dimethoxyethane, acetonitrile, hexane, toluene, diethyl ether, chloroform, ethyl acetate, tetrahydrofuran, and methylene chloride.
- N, N-dimethylformamide, dimethylsulfoxide, acetic acid, formic acid and the like can be used.
- the above organic solvents may be used alone or in combination of two or more.
- the organic solvent used in the washing step includes a hydrophilic organic solvent having high mutual solubility in both water and the low surface tension solvent.
- the hydrophilic organic solvent used in the washing step can serve as a preliminary replacement for the solvent replacement step.
- examples of the hydrophilic organic solvent include methanol, ethanol, 2-propanol, acetone, and methyl ethyl ketone.
- methanol, ethanol, methyl ethyl ketone, etc. are excellent in terms of economy.
- the amount of water or the organic solvent used in the washing step can be set to an amount that can sufficiently replace the solvent in the wet gel and can be washed.
- the amount can be 3 to 10 times the volume of the wet gel. Washing can be repeated until the water content in the wet gel after washing becomes 10% by mass or less based on the mass of silica.
- the temperature environment in the washing step can be a temperature equal to or lower than the boiling point of the solvent used for washing.
- the temperature can be raised to about 30 to 60 ° C.
- the solvent of the washed wet gel is replaced with a predetermined replacement solvent in order to suppress shrinkage of the airgel in the drying step.
- the replacement efficiency can be improved by heating.
- the substitution solvent specifically, in the drying step, when drying at a temperature lower than the critical point of the solvent used for drying under atmospheric pressure, a solvent having a low surface tension, which will be described later, may be mentioned.
- the replacement solvent include ethanol, methanol, 2-propanol, dichlorodifluoromethane, carbon dioxide, and the like, or a solvent obtained by mixing two or more of these.
- Examples of the solvent having a low surface tension include a solvent having a surface tension at 30C of 30 mN / m or less.
- the surface tension may be 25 mN / m or less, or 20 mN / m or less.
- low surface tension solvents examples include pentane (15.5), hexane (18.4), heptane (20.2), octane (21.7), 2-methylpentane (17.4), Aliphatic hydrocarbons such as methylpentane (18.1), 2-methylhexane (19.3), cyclopentane (22.6), cyclohexane (25.2) and 1-pentene (16.0); benzene Aromatic hydrocarbons such as (28.9), toluene (28.5), m-xylene (28.7) and p-xylene (28.3); dichloromethane (27.9), chloroform (27.2) ), Carbon tetrachloride (26.9), 1-chloropropane (21.8), 2-chloropropane (18.1) and other halogenated hydrocarbons; ethyl ether (17.1), propyl ether (20.5) ), Isop Ethers such as pill ether (17.7), butyl
- aliphatic hydrocarbons (hexane, heptane, etc.) have low surface tension and excellent work environment.
- a hydrophilic organic solvent such as acetone, methyl ethyl ketone, and 1,2-dimethoxyethane
- the organic solvent can also be used as the organic solvent in the washing step.
- a solvent having a boiling point at normal pressure of 100 ° C. or lower may be used because drying in a drying step described later is easy.
- the above solvents may be used alone or in combination of two or more.
- the amount of the solvent used in the solvent replacement step can be set to an amount that can sufficiently replace the solvent in the wet gel after washing.
- the amount can be 3 to 10 times the volume of the wet gel.
- the temperature environment in the solvent replacement step can be a temperature equal to or lower than the boiling point of the solvent used for replacement.
- the temperature can be raised to about 30 to 60 ° C.
- the solvent replacement step is not essential.
- the inferred mechanism is as follows. That is, since the silica particles function as a support for the three-dimensional network skeleton, the skeleton is supported, and shrinkage of the gel in the drying step is suppressed. Therefore, it is considered that the gel can be directly subjected to the drying step without replacing the solvent used for washing. As described above, the use of the silica particles makes it possible to simplify the washing and solvent replacement steps to the drying step.
- the method of drying is not particularly limited, and known atmospheric drying, supercritical drying or freeze drying can be used.
- normal pressure drying or supercritical drying can be used from the viewpoint of easily producing a low-density airgel. From the viewpoint of production at low cost, normal pressure drying can be used.
- the normal pressure means 0.1 MPa (atmospheric pressure).
- the aerogel can be obtained by drying the wet gel after washing and (if necessary) solvent replacement at a temperature below the critical point of the solvent used for drying under atmospheric pressure.
- the drying temperature varies depending on the type of solvent that has been replaced (the solvent used for washing if solvent replacement is not performed), especially when drying at high temperatures increases the evaporation rate of the solvent and causes large cracks in the gel.
- the temperature can be set to 20 to 150 ° C.
- the drying temperature may be 60 to 120 ° C.
- the drying time varies depending on the volume of the wet gel and the drying temperature, but can be 4 to 120 hours. It should be noted that the drying under a normal pressure includes applying a pressure lower than the critical point within a range not impairing the productivity to accelerate the drying.
- Airgel can also be obtained by supercritical drying of a wet gel that has been washed and (if necessary) replaced with a solvent.
- Supercritical drying can be performed by a known method.
- a method of supercritical drying for example, a method of removing the solvent at a temperature and a pressure higher than the critical point of the solvent contained in the wet gel may be mentioned.
- the wet gel is immersed in liquefied carbon dioxide, for example, at a temperature of about 20 to 25 ° C. and about 5 to 20 MPa, so that all or a part of the solvent contained in the wet gel is dried. Is replaced with carbon dioxide having a lower critical point than the solvent, and then carbon dioxide alone or a mixture of carbon dioxide and a solvent is removed.
- the airgel obtained by such normal pressure drying or supercritical drying may be additionally dried at 105 to 200 ° C. under normal pressure for about 0.5 to 2 hours. This makes it easier to obtain an airgel having a low density and small pores.
- the additional drying may be performed at 150 to 200 ° C. under normal pressure.
- the airgel (aerogel block) obtained by drying is pulverized to obtain airgel particles.
- it can be carried out by putting aerogel into a jet mill, roller mill, bead mill, hammer mill or the like and operating at an appropriate rotation speed and time.
- the coating liquid contains the airgel particles, the binder resin, and the liquid medium described above.
- the binder resin has a function of binding the airgel particles after forming the coating film.
- the binder resin for example, epoxy resin, silicone resin, phenol resin, urea resin, melamine resin, polyurethane resin, polyethylene resin, polypropylene resin, polystyrene resin, polyester resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, Examples thereof include a polyamide resin, a polyimide resin, a cellulose resin, and a polyvinyl resin.
- silicone resin, acrylic resin, phenol resin and polyester resin can be preferably used.
- cellulose resin for example, hydroxypropylmethylcellulose, carboxymethylcellulose ammonium, hydroxyethylmethylcellulose and the like can be mentioned.
- polyvinyl resin examples include polyvinyl alcohol and polyvinyl pyrrolidone.
- the coating liquid may further contain a curing agent.
- the curing agent is not particularly limited, and may be appropriately changed according to the type of the thermosetting resin.
- the thermosetting resin is an epoxy resin
- a known epoxy resin curing agent can be used as the curing agent.
- the epoxy resin curing agent include, for example, an amine curing agent, an acid anhydride curing agent, a polyamide curing agent, and the like. From the viewpoint of reactivity, preferably use an amine curing agent and a polyamide curing agent. Can be.
- Liquid media include water and organic solvents.
- the organic solvent is not particularly limited as long as it can disperse the airgel particles. Examples thereof include aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene and p-cymene; and aliphatic hydrocarbons such as hexane, heptane and pentane.
- Hydrocarbons such as diethyl ether, tetrahydrofuran, and 1,4-dioxane; alcohols such as methanol, ethanol, isopropanol (isopropyl alcohol), butanol, ethylene glycol and propylene glycol; acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone And ketones such as 4-hydroxy-4-methyl-2-pentanone; esters such as methyl acetate, ethyl acetate and butyl acetate; N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolid An amide such as emissions and the like.
- ethers such as diethyl ether, tetrahydrofuran, and 1,4-dioxane
- alcohols such as methanol, ethanol, isopropanol (isopropyl alcohol), butanol,
- alcohols and ketones can be used from the viewpoints of volatility, boiling point, and the like, and alcohols can be particularly preferably used. Since alcohols and ketones can be easily mixed with water, an aqueous resin or the like, they are also suitable when used in combination with those components.
- the coating liquid may contain a thickener, a fibrous substance, a pigment, a leveling agent and the like as other components.
- the thickener can improve the viscosity of the coating liquid and improve the coating property for the object.
- examples of the thickener include fine particles such as fumed silica and clay mineral.
- the fibrous substance can exhibit an anchor function between the airgel particles after the formation of the coating film, and can further improve the coating film strength.
- the fibrous substance is not particularly limited, and includes organic fibers and inorganic fibers.
- the organic fiber include polyamide fiber, polyimide fiber, polyvinyl alcohol fiber, polyvinylidene chloride fiber, polyvinyl chloride fiber, polyester fiber, polyacrylonitrile fiber, polyethylene fiber, polypropylene fiber, and polyurethane fiber. Fiber, phenolic fiber, polyetherester fiber, polylactic acid fiber, polycarbonate fiber and the like.
- the inorganic fibers include glass fibers, carbon fibers, ceramic fibers, and metal fibers.
- the coating liquid of the present embodiment contains a larger amount of airgel particles than in the past, and the content of airgel particles in the coating liquid is 20% by mass or more. From the viewpoint of obtaining a lower-density coating film, the content can be 25% by mass or more, may be 30% by mass or more, or may be more than 30% by mass.
- the upper limit of the content is not particularly limited, but may be 50% by mass from the viewpoint of the dispersibility of the airgel particles, good coating properties, and the like.
- the content of the binder resin in the coating liquid may be 1% by mass or more, and may be 2% by mass or more from the viewpoints of the binding property between the airgel particles and the heat insulating property of the coating film. It may be not less than mass%. Further, the content can be 10% by mass or less, but may be 7% by mass or less, or may be 5% by mass or less.
- the content of the binder resin in the coating liquid can be, for example, 5 parts by mass or more with respect to 100 parts by mass of the airgel particles, but may be 7 parts by mass or more, or 10 parts by mass or more. And may be 12 parts by mass or more. This makes it easier for the airgel particles to be firmly bound by the binder resin, further improving the strength of the coating film.
- the content of the binder resin can be, for example, 20 parts by mass or less with respect to 100 parts by mass of the airgel particles, but may be 18 parts by mass or less, or may be 15 parts by mass or less. .
- the ratio of the airgel particles in the coating film is increased, the density of the coating film can be reduced, and the heat insulating property of the coating film is further improved.
- the content of the fibrous substance in the coating liquid can be 0.01 to 30% by mass from the viewpoints of dispersibility in the coating liquid, good anchor function, and the like. It may be 10% by mass.
- the content of the fibrous substance in the coating liquid can be, for example, 5 parts by mass or more with respect to 100 parts by mass of the airgel particles, but may be 7 parts by mass or more, or 9 parts by mass or more. You may. Thereby, the anchor effect by the fibrous substance is easily obtained, and the coating film strength is further improved.
- the content of the fibrous substance can be, for example, 50 parts by mass or less based on 100 parts by mass of the airgel particles, but may be 35 parts by mass or less, or 25 parts by mass or less.
- the amount may be 20 parts by mass or less, or 15 parts by mass or less.
- the content of the thickener can be appropriately adjusted so as to have a desired coating liquid viscosity (for example, 1000 mPa ⁇ s or more). Since the viscosity of the coating liquid can be improved by blending a binder resin, in such a case, it is not always necessary to blend a thickener.
- the ratio of the airgel particles to the entire solid content in the coating liquid can be 90% by volume or more, but may be 95% by volume or more, or may be 98% by volume or more.
- the ratio of the binder resin to the entire solid content in the coating liquid can be 3% by volume or less, but may be 2.5% by volume or less, or may be 2% by volume or less.
- the liquid medium may contain water as a main component (for example, 90% by mass or more). Water is less likely to penetrate into the porous structure of the water-repellent airgel particles, so that the application of the liquid becomes easier.
- the liquid medium may contain an organic solvent in order to further improve the kneading properties of the airgel particles and the binder resin.
- the content of the organic solvent in the liquid medium may be 1% by mass or more, may be 3% by mass or more, and may be 5% by mass or more.
- the specific gravity of the coating liquid can be 0.8 or less, but may be 0.77 or less, or 0.75 or less.
- the lower limit of the specific gravity can be set to 0.35, and may be set to 0.6, from the viewpoint of easily forming a coating film while suppressing the occurrence of cracks.
- the specific gravity of the coating solution can be measured at room temperature (10 to 30 ° C.) using a disposable syringe. Specifically, a 2.5 mL disposable syringe is filled with 1.5 mL or more of the coating liquid, and after evacuating the air in the syringe, the total weight (A) of the syringe and the coating liquid is measured.
- the total weight (B) of the syringe and the coating liquid in the syringe after extruding 1.0 mL of the coating liquid from the syringe is measured.
- the specific gravity of the coating liquid can be calculated by setting the weight difference between (A) and (B) as the weight per 1.0 mL of the coating liquid.
- the specific gravity of the coating liquid can be measured by a laser volume meter, a float, a specific gravity meter, or the like, in addition to the above-described method using a syringe.
- the coating liquid according to the present embodiment can be referred to as an airgel particle-containing coating liquid, but may be in a paste form depending on the viscosity, and can be referred to as an airgel particle-containing paste.
- the coating liquid can be prepared by stirring (mixing) a raw material containing at least airgel particles, a binder resin and a liquid medium using one or more commercially available mixers.
- a mixer include a shear stirrer such as a rotation-revolving mixer, a low-speed shear stirrer such as a planetary mixer (planetary mixer), and a high-speed shear stirrer such as a homomixer.
- the stirring speed can be 500 to 1500 rpm, and the stirring time can be 1 to 60 minutes.
- the stirring conditions when using a planetary mixer can be a stirring speed of 8 to 200 rpm and a stirring time of 1 to 120 minutes.
- the homomixer is preferably used in combination with the main stirring by these mixers, and particularly preferably used as a preliminary stirring means for the main stirring.
- the stirring of the present embodiment can include a high-speed shearing and stirring step of stirring the raw material by a high-speed shearing stirrer and a subsequent low-speed shearing and stirring step of stirring by a low-speed shearing stirrer.
- the stirring conditions may be a stirring speed of 1000 to 3000 rpm and a stirring time of 1 to 20 minutes.
- Examples of the rotation-revolution type mixer include the Awatori Rentaro series (Shinky Co., Ltd., product name), ME-N300BR (Beat Sensing Co., Ltd., product name), Hi-Maja (AS-ONE Co., Ltd., product name) and the like.
- Can be Planetary mixers series include Planetary Mixer Series (product name, Inoue Manufacturing Co., Ltd.), PD Mixer Series (product name, Inoue Manufacturing Co., Ltd.), Hibis Mix Series (product name, manufactured by Primix Co., Ltd.), Hibis Dispermix series (product name, manufactured by Primix Corporation) and the like.
- Examples of the homomixer include an L5 series (manufactured by SILVERSON, product name) and a homomixer MARKII series (manufactured by Primix, product name).
- the coating film can be formed by removing the liquid medium from the coating liquid containing the airgel particles, the binder resin, and the liquid medium. More specifically, a method for producing a coating film (a method for forming a coating film) includes a step of applying the above-described coating liquid on an object, and a step of removing a liquid medium from the coating liquid applied on the object. , Can be provided.
- the method of applying the coating liquid on the object is not particularly limited, and examples thereof include dip coating, spray coating, spin coating, and roll coating.
- the applied coating liquid is subjected to a heating (for example, 40 to 150 ° C.) treatment, a reduced pressure (for example, 10,000 Pa or less) treatment, or both of these treatments, so that the coating liquid is converted to a liquid medium. May be removed.
- the content of the airgel particles in the coating film can be, for example, 80% by mass or more, but may be 85% by mass or more, or 90% by mass or more. As a result, the coating film density is reduced, and the heat insulating properties of the coating film are further improved.
- the content of the airgel particles in the coating film can be, for example, 95% by mass or less, but may be 93% by mass or less. Thereby, a coating film tends to be easily formed.
- the proportion of the airgel particles in the coating film can be 90% by volume or more, but may be 95% by volume or more, or 98% by volume or more. Further, the ratio of the binder resin in the coating film can be 3% by volume or less, but may be 2.5% by volume or less, or may be 2% by volume or less.
- the density of the coating may be 0.4 g / cm 3 or less, but may be 0.37 g / cm 3 or less, or 0.35 g / cm 3 or less.
- the lower limit of the density of the coating film is not particularly limited, it may be 0.1 g / cm 3 or may be 0.2 g / cm 3 from the viewpoint of easily obtaining good coating strength.
- the density of the coating film can be measured by the “method of measuring density and specific gravity by weighing in liquid” or “the measuring method of density and specific gravity by geometrical measurement” described in JIS Z 8827: 2012.
- the thickness of the coating film is not particularly limited, and may be, for example, 0.01 to 5 mm.
- the material constituting the object is not particularly limited, and examples thereof include metal, ceramic, glass, resin, and composite materials thereof.
- the form of the target object can be appropriately selected according to the purpose or material used, and includes a block shape, a sheet shape, a powder shape, a fiber shape, and the like.
- the coating film has excellent heat insulation, heat resistance, flame retardancy, etc. derived from aerogel. Due to such advantages, the coating film can be applied to a cryogenic container, a space field, an architectural field, an automobile field, a home appliance field, a semiconductor field, a heat insulating material in industrial equipment, and the like.
- the coating film can be used not only as a heat insulating material but also as a water repellent material, a sound absorbing material, a vibration damping material, a catalyst supporting material, and the like.
- the "polysiloxane compound X" was synthesized as follows. First, in a 1-liter three-necked flask equipped with a stirrer, a thermometer and a Dimroth condenser, dimethylpolysiloxane XC96-723 having silanol groups at both ends (manufactured by Momentive Performance Materials Japan GK. (Product name), 101.3 parts by mass of methyltrimethoxysilane, and 0.50 parts by mass of t-butylamine were mixed and reacted at 30 ° C. for 5 hours. Thereafter, this reaction solution was heated at 140 ° C. for 2 hours under a reduced pressure of 1.3 kPa to remove volatile components, thereby obtaining a bifunctional alkoxy-modified polysiloxane compound at both ends (polysiloxane compound X).
- the obtained wet gel was transferred to a plastic bottle, sealed, and then pulverized for 10 minutes at 27,000 rpm using an extreme mill (manufactured by As One Corporation, MX-1000XTS) to obtain a particulate wet gel. .
- the obtained particulate wet gel was immersed in 2500.0 parts by mass of methanol and washed at 25 ° C. for 24 hours. This washing operation was performed three times in total while exchanging with fresh methanol.
- the washed particulate wet gel was immersed in 2500.0 parts by mass of heptane as a low surface tension solvent, and the solvent was replaced at 25 ° C. for 24 hours.
- This solvent replacement operation was performed a total of three times while exchanging for new heptane.
- the washed and solvent-substituted particulate wet gel was dried at 40 ° C. for 96 hours under normal pressure, and further dried at 150 ° C. for 2 hours. Finally, it was sieved (Tokyo Screen Co., Ltd., mesh size: 45 ⁇ m, wire diameter: 32 ⁇ m) to obtain the airgel particles A having the structures represented by the general formulas (3), (4) and (5).
- JIOS AeroVa (registered trademark, manufactured by JIOS AEROGEL CORPORATION, product name) was prepared as the airgel particles B.
- the BET specific surface area of the airgel particles was measured using a gas adsorption amount measurement device (Autosorb-iQ (Autosorb is a registered trademark) manufactured by Kantachrome Instruments Japan GK).
- the specific surface area of the airgel particles A was 125 m 2 / g
- the specific surface area of the airgel particles B was 716 m 2 / g.
- Example 1 0.50 g of Marpolose MP30000 (manufactured by Matsumoto Yushi Co., Ltd., product name, specific gravity: 1.2) as hydroxypropyl methylcellulose in a dedicated container of Awatori Nerita ARV-310 (manufactured by Shinky Inc., product name), 1 g of specific gravity 0.78), 10 g of water, and 5.00 g of airgel particles A were added. Then, the lid of the container was closed, and the mixture was stirred at a stirring speed of 1000 rpm for 10 minutes to obtain a coating liquid of Example 1.
- Example 2 5.00 g of Marpolose MP30000 and 10 g of isopropyl alcohol were placed in a 100 mL polycup, and stirred with a spoonful of scoop to prepare a dispersion of MP30000. Next, 100 g of pure water was placed in a 500 mL polycup, and the whole amount of the above dispersion was added while stirring the pure water at 2000 rpm using a homomixer L5R (manufactured by SILVERSON, product name). The stirring time was 3 minutes. Thus, a base solution was prepared.
- Example 2 a coating liquid of Example 2 was obtained.
- a coating liquid was prepared in the same manner as in Example 1, except that the raw materials and the stirring method of the coating liquid were changed as shown in Table 1 or 2.
- the coating solution obtained in each case was placed in a vertically long glass container like a measuring cylinder, and the container was covered. After standing in that state for 60 minutes, the state of the coating liquid was visually observed.
- the evaluation criteria were as follows. Good: A cloudy paste was formed. Poor: The liquid component and the airgel particles were separated, and a supernatant of 1% by volume or more of the entire coating liquid was generated.
- the specific gravity of the coating liquid obtained in each example was measured using a disposable syringe (manufactured by Terumo Corporation, capacity: 2.5 mL). Specifically, at room temperature (10 to 30 ° C), remove the plunger from the syringe, fill the syringe with a spoon using a spoon so that air bubbles do not enter the coating solution, and set the plunger again. To remove air bubbles at the tip of the syringe. Using an electronic balance, the difference between the weight of the entire syringe including the coating liquid and the weight after discharging 1 mL of the coating liquid was defined as the weight per 1 mL of the coating liquid, and the specific gravity of the coating liquid was calculated.
- a coating film was formed using the coating liquid obtained in each example. Specifically, the coating liquid was applied on an aluminum foil using a metal spatula so as to have a thickness of 2 mm. Then, the liquid medium was removed from the coating liquid by heating at 120 ° C. for 1 hour to obtain a coating film. The obtained coating film was visually observed and evaluated according to the following evaluation criteria. Good: had a good appearance without cracks. Poor: cracks occurred.
- the density of the coating film obtained in the above evaluation of the film forming property was measured. Specifically, the obtained coating film was cut into a size of 3 cm ⁇ 3 cm to obtain a measurement sample, and the measurement sample was measured using a hydrometer (MDS-300, manufactured by Alpha Mirage Co., Ltd.) equipped with a water tank having a water temperature of 20 ° C. The weight in the air and in the water was measured to obtain the specific gravity of the coating film.
- MDS-300 manufactured by Alpha Mirage Co., Ltd.
Landscapes
- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Wood Science & Technology (AREA)
- Organic Chemistry (AREA)
- Silicon Polymers (AREA)
- Paints Or Removers (AREA)
- Silicon Compounds (AREA)
Abstract
The present invention pertains to a coating liquid which contains aerogel particles, a binder resin and a liquid medium, wherein the aerogel particle content is at least 20 mass%. The present invention also pertains to a coating film which contains aerogel particles and a binder resin, wherein the aerogel particle content is at least 80 mass% and the density thereof is 0.4 g/cm3 or less.
Description
本発明は、塗液及び塗膜に関する。
The present invention relates to a coating liquid and a coating film.
断熱性、透明性等に優れる材料としてエアロゲルが知られている。このような特性を有するエアロゲルを粒子状に加工し、断熱材の構成材料として用いる方法が提案されている(例えば、特許文献1)。特許文献1では、粒子状のエアロゲルを、断熱窓を構成する樹脂板等の間の充填材として用いることが提案されている。
エ ア Aerogel is known as a material having excellent heat insulating properties and transparency. A method has been proposed in which aerogel having such properties is processed into particles and used as a constituent material of a heat insulating material (for example, Patent Document 1). Patent Literature 1 proposes using particulate aerogel as a filler between resin plates and the like constituting a heat insulating window.
エアロゲル粒子を充填剤として粒子のまま取り扱う場合、上記のようにエアロゲル粒子以外の構成が不可欠である。一方で、エアロゲル粒子の層を対象の表面に直接形成することができれば、構成をよりシンプルにすることができ、また層形成時に対象の表面形状による制約も受け難い。
取 り 扱 う When handling airgel particles as particles as a filler, a configuration other than the airgel particles is indispensable as described above. On the other hand, if the layer of the airgel particles can be formed directly on the surface of the object, the configuration can be made simpler, and the layer shape is hardly restricted by the surface shape of the object.
本発明は上記の事情に鑑みてなされたものであり、新規なエアロゲル粒子含有塗液を提供することを目的とする。本発明はまた、当該塗液を用いて得られる塗膜を提供することを目的とする。
The present invention has been made in view of the above circumstances, and has an object to provide a novel airgel particle-containing coating liquid. Another object of the present invention is to provide a coating film obtained by using the coating liquid.
本発明は、エアロゲル粒子、バインダ樹脂及び液状媒体を含み、エアロゲル粒子の含有量が20質量%以上である、塗液を提供する。本発明の塗液中には、従来に比して多量のエアロゲル粒子が分散状態で存在している。そのため、対象表面に、エアロゲル粒子を密に含む塗膜を形成することができる。塗液中に多量のエアロゲル粒子を分散させることができた一因としては、分散方法を適切に調整したことが挙げられる。
The present invention provides a coating liquid containing airgel particles, a binder resin and a liquid medium, wherein the content of the airgel particles is 20% by mass or more. In the coating liquid of the present invention, a larger amount of airgel particles than in the prior art is present in a dispersed state. Therefore, a coating film containing airgel particles densely can be formed on the target surface. One reason that a large amount of airgel particles could be dispersed in the coating liquid is that the dispersion method was appropriately adjusted.
本発明の塗液において、液状媒体は水を含むことができる。また、当該液状媒体はさらに有機溶媒を含むことができる。
液状 In the coating liquid of the present invention, the liquid medium can contain water. In addition, the liquid medium can further include an organic solvent.
本発明の塗液において、バインダ樹脂は、エポキシ樹脂、シリコーン樹脂、フェノール樹脂、尿素樹脂、メラミン樹脂、ポリウレタン樹脂、ポリエチレン樹脂、ポリプロピレン樹脂、ポリスチレン樹脂、ポリエステル樹脂、アクリル樹脂、ポリ塩化ビニル樹脂、ポリ酢酸ビニル樹脂、ポリアミド樹脂、ポリイミド樹脂、セルロース系樹脂、及びポリビニル系樹脂からなる群より選択される少なくとも一種を含むことができる。これにより成膜性をより向上することができる。
In the coating liquid of the present invention, the binder resin is an epoxy resin, a silicone resin, a phenol resin, a urea resin, a melamine resin, a polyurethane resin, a polyethylene resin, a polypropylene resin, a polystyrene resin, a polyester resin, an acrylic resin, a polyvinyl chloride resin, At least one selected from the group consisting of vinyl acetate resin, polyamide resin, polyimide resin, cellulose resin, and polyvinyl resin can be included. Thereby, the film formability can be further improved.
本発明の塗液の比重は0.8以下とすることができる。
比 The specific gravity of the coating liquid of the present invention can be 0.8 or less.
本発明はまた、エアロゲル粒子及びバインダ樹脂を含み、エアロゲル粒子の含有量が80質量%以上であり、密度が0.4g/cm3以下である、塗膜を提供する。従来、このようにエアロゲル粒子が高充填された軽質な塗膜(エアロゲル塗膜)は非常に得難かったが、上記本発明の塗液を用いることでこれを実現することが可能となった。
The present invention also provides a coating film containing airgel particles and a binder resin, wherein the content of the airgel particles is 80% by mass or more and the density is 0.4 g / cm 3 or less. Conventionally, it has been very difficult to obtain a light coating film (aerogel coating film) in which airgel particles are highly filled as described above. However, this can be realized by using the coating liquid of the present invention.
本発明の塗膜において、バインダ樹脂は、エポキシ樹脂、シリコーン樹脂、フェノール樹脂、尿素樹脂、メラミン樹脂、ポリウレタン樹脂、ポリエチレン樹脂、ポリプロピレン樹脂、ポリスチレン樹脂、ポリエステル樹脂、アクリル樹脂、ポリ塩化ビニル樹脂、ポリ酢酸ビニル樹脂、ポリアミド樹脂、ポリイミド樹脂、セルロース系樹脂、及びポリビニル系樹脂からなる群より選択される少なくとも一種を含むことができる。これにより膜質をより向上することができる。
In the coating film of the present invention, the binder resin is an epoxy resin, silicone resin, phenol resin, urea resin, melamine resin, polyurethane resin, polyethylene resin, polypropylene resin, polystyrene resin, polyester resin, acrylic resin, polyvinyl chloride resin, poly At least one selected from the group consisting of vinyl acetate resin, polyamide resin, polyimide resin, cellulose resin, and polyvinyl resin can be included. Thereby, the film quality can be further improved.
本発明によれば、新規なエアロゲル粒子含有塗液を提供することができる。また、本発明によれば、当該塗液を用いて得られる塗膜(エアロゲル塗膜)を提供することができる。
According to the present invention, a novel airgel particle-containing coating liquid can be provided. Further, according to the present invention, a coating film (airgel coating film) obtained by using the coating liquid can be provided.
以下、本発明の好適な実施形態について詳細に説明する。ただし、本発明は以下の実施形態に限定されるものではない。本明細書において、「~」を用いて示された数値範囲は、「~」の前後に記載される数値をそれぞれ最小値及び最大値として含む範囲を示す。「A又はB」とは、A及びBのいずれか一方を含んでいればよく、両方を含んでいてもよい。本実施形態で例示する材料は、特に断らない限り、1種を単独で又は2種以上を組み合わせて用いることができる。
Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. In this specification, a numerical range indicated by using “to” indicates a range including numerical values described before and after “to” as a minimum value and a maximum value, respectively. “A or B” may include any one of A and B, and may include both. The materials exemplified in the present embodiment can be used alone or in combination of two or more, unless otherwise specified.
<エアロゲル粒子>
狭義には、湿潤ゲルに対して超臨界乾燥法を用いて得られた乾燥ゲルをエアロゲル、大気圧下での乾燥により得られた乾燥ゲルをキセロゲル、凍結乾燥により得られた乾燥ゲルをクライオゲルと称するが、本実施形態においては、湿潤ゲルのこれらの乾燥手法によらず、得られた低密度の乾燥ゲルを「エアロゲル」と称する。すなわち、本実施形態において、「エアロゲル」とは、広義のエアロゲルである「Gel comprised of a microporous solid in which the dispersed phase is a gas(分散相が気体である微多孔性固体から構成されるゲル)」を意味する。一般的に、エアロゲルの内部は、網目状の微細構造を有しており、2~20nm程度の粒子状のエアロゲル成分が結合したクラスター構造を有している。このクラスターにより形成される骨格間には、100nmに満たない細孔がある。これにより、エアロゲルは、三次元的に微細な多孔性の構造が形成されている。なお、本実施形態に係るエアロゲルは、例えば、シリカを主成分とするシリカエアロゲルである。シリカエアロゲルとしては、例えば、有機基(メチル基等)又は有機鎖を導入した、いわゆる有機-無機ハイブリッド化されたシリカエアロゲルが挙げられる。 <Aerogel particles>
In a narrow sense, a dry gel obtained by using a supercritical drying method for a wet gel is aerogel, a dry gel obtained by drying under atmospheric pressure is a xerogel, and a dry gel obtained by freeze-drying is a cryogel. In this embodiment, the obtained low-density dried gel is referred to as “aerogel” regardless of the method for drying the wet gel. That is, in the present embodiment, “aerogel” is a broadly defined aerogel, “Gel-complied of a microporous solid in which the dispersed phase is a gas (a gel composed of a microporous solid whose dispersed phase is a gas). Means. Generally, the inside of the airgel has a network-like fine structure, and has a cluster structure in which a particulate airgel component of about 2 to 20 nm is bonded. There are pores smaller than 100 nm between the skeletons formed by the clusters. Thereby, the airgel has a three-dimensionally fine porous structure. The aerogel according to the present embodiment is, for example, a silica aerogel containing silica as a main component. Examples of the silica airgel include a so-called organic-inorganic hybridized silica airgel into which an organic group (eg, a methyl group) or an organic chain is introduced.
狭義には、湿潤ゲルに対して超臨界乾燥法を用いて得られた乾燥ゲルをエアロゲル、大気圧下での乾燥により得られた乾燥ゲルをキセロゲル、凍結乾燥により得られた乾燥ゲルをクライオゲルと称するが、本実施形態においては、湿潤ゲルのこれらの乾燥手法によらず、得られた低密度の乾燥ゲルを「エアロゲル」と称する。すなわち、本実施形態において、「エアロゲル」とは、広義のエアロゲルである「Gel comprised of a microporous solid in which the dispersed phase is a gas(分散相が気体である微多孔性固体から構成されるゲル)」を意味する。一般的に、エアロゲルの内部は、網目状の微細構造を有しており、2~20nm程度の粒子状のエアロゲル成分が結合したクラスター構造を有している。このクラスターにより形成される骨格間には、100nmに満たない細孔がある。これにより、エアロゲルは、三次元的に微細な多孔性の構造が形成されている。なお、本実施形態に係るエアロゲルは、例えば、シリカを主成分とするシリカエアロゲルである。シリカエアロゲルとしては、例えば、有機基(メチル基等)又は有機鎖を導入した、いわゆる有機-無機ハイブリッド化されたシリカエアロゲルが挙げられる。 <Aerogel particles>
In a narrow sense, a dry gel obtained by using a supercritical drying method for a wet gel is aerogel, a dry gel obtained by drying under atmospheric pressure is a xerogel, and a dry gel obtained by freeze-drying is a cryogel. In this embodiment, the obtained low-density dried gel is referred to as “aerogel” regardless of the method for drying the wet gel. That is, in the present embodiment, “aerogel” is a broadly defined aerogel, “Gel-complied of a microporous solid in which the dispersed phase is a gas (a gel composed of a microporous solid whose dispersed phase is a gas). Means. Generally, the inside of the airgel has a network-like fine structure, and has a cluster structure in which a particulate airgel component of about 2 to 20 nm is bonded. There are pores smaller than 100 nm between the skeletons formed by the clusters. Thereby, the airgel has a three-dimensionally fine porous structure. The aerogel according to the present embodiment is, for example, a silica aerogel containing silica as a main component. Examples of the silica airgel include a so-called organic-inorganic hybridized silica airgel into which an organic group (eg, a methyl group) or an organic chain is introduced.
本実施形態におけるエアロゲル粒子は特に限定されず、種々の公知の製造方法により製造されたエアロゲル粒子を用いることができる。一例として、本実施形態のエアロゲル粒子を構成し得るエアロゲルについて説明する。当該エアロゲルは、後述するように、加水分解性の官能基又は縮合性の官能基を有するケイ素化合物、及び、加水分解性の官能基を有するケイ素化合物の加水分解生成物からなる群より選択される少なくとも一種、を含有するゾルの縮合物である湿潤ゲルの乾燥物(ゾルから生成された湿潤ゲルを乾燥して得られるもの:ゾル由来の湿潤ゲルの乾燥物)である。
は The airgel particles in the present embodiment are not particularly limited, and airgel particles manufactured by various known manufacturing methods can be used. As an example, an airgel that can constitute the airgel particles of the present embodiment will be described. The airgel is selected from the group consisting of a silicon compound having a hydrolyzable functional group or a condensable functional group, and a hydrolysis product of a silicon compound having a hydrolyzable functional group, as described below. It is a dried product of a wet gel which is a condensate of a sol containing at least one (a product obtained by drying a wet gel generated from a sol: a dried product of a wet gel derived from a sol).
本実施形態に係るエアロゲルは、下記一般式(1)で表される構造を有することができる。本実施形態に係るエアロゲルは、式(1)で表される構造を含む構造として、下記一般式(1a)で表される構造を有することができる。
The airgel according to the present embodiment can have a structure represented by the following general formula (1). The airgel according to the present embodiment can have a structure represented by the following general formula (1a) as a structure including the structure represented by the formula (1).
式(1)及び式(1a)中、R1及びR2はそれぞれ独立にアルキル基又はアリール基を示し、R3及びR4はそれぞれ独立にアルキレン基を示す。ここで、アリール基としてはフェニル基、置換フェニル基等が挙げられる。なお、置換フェニル基の置換基としては、アルキル基、ビニル基、メルカプト基、アミノ基、ニトロ基、シアノ基等が挙げられる。pは1~50の整数を示す。式(1a)中、2個以上のR1は各々同一であっても異なっていてもよく、同様に、2個以上のR2は各々同一であっても異なっていてもよい。式(1a)中、2個のR3は各々同一であっても異なっていてもよく、同様に、2個のR4は各々同一であっても異なっていてもよい。
In the formulas (1) and (1a), R 1 and R 2 each independently represent an alkyl group or an aryl group, and R 3 and R 4 each independently represent an alkylene group. Here, examples of the aryl group include a phenyl group and a substituted phenyl group. In addition, examples of the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group. p represents an integer of 1 to 50. In formula (1a), two or more R 1 may be the same or different, and similarly, two or more R 2 may be the same or different. In the formula (1a), two R 3 may be the same or different, and similarly, two R 4 may be the same or different.
上記式(1)又は式(1a)で表される構造をエアロゲル成分としてエアロゲルの骨格中に導入することにより、低熱伝導率かつ柔軟なエアロゲルとなる。このような観点から、式(1)及び式(1a)中、R1及びR2としてはそれぞれ独立に炭素数が1~6のアルキル基、フェニル基等が挙げられ、当該アルキル基としてはメチル基等が挙げられる。また、式(1)及び式(1a)中、R3及びR4としてはそれぞれ独立に炭素数が1~6のアルキレン基等が挙げられ、当該アルキレン基としてはエチレン基、プロピレン基等が挙げられる。式(1a)中、pは2~30とすることができ、5~20であってもよい。
By introducing the structure represented by the above formula (1) or (1a) into the skeleton of the aerogel as an aerogel component, a flexible aerogel with low thermal conductivity is obtained. From such a viewpoint, in the formulas (1) and (1a), R 1 and R 2 each independently include an alkyl group having 1 to 6 carbon atoms, a phenyl group, and the like. And the like. In Formulas (1) and (1a), R 3 and R 4 each independently include an alkylene group having 1 to 6 carbon atoms, and the alkylene group includes an ethylene group, a propylene group, and the like. Can be In the formula (1a), p may be 2 to 30, and may be 5 to 20.
本実施形態に係るエアロゲルは、また、支柱部及び橋かけ部を備えるラダー型構造を有し、かつ橋かけ部が下記一般式(2)で表される構造を有することができる。このようなラダー型構造をエアロゲル成分としてエアロゲルの骨格中に導入することにより、耐熱性と機械的強度を向上させることができる。なお、本実施形態において「ラダー型構造」とは、2本の支柱部(struts)と支柱部同士を連結する橋かけ部(bridges)とを有するもの(いわゆる「梯子」の形態を有するもの)である。本態様において、エアロゲルの骨格がラダー型構造からなっていてもよいが、エアロゲルが部分的にラダー型構造を有していてもよい。
The aerogel according to the present embodiment also has a ladder-type structure including a support portion and a bridge portion, and the bridge portion may have a structure represented by the following general formula (2). By introducing such a ladder-type structure as an airgel component into the skeleton of the airgel, heat resistance and mechanical strength can be improved. In this embodiment, the “ladder type structure” refers to a structure having two struts and bridges connecting the struts (bridges) (having a so-called “ladder” form). It is. In this embodiment, the skeleton of the airgel may have a ladder-type structure, but the airgel may have a ladder-type structure partially.
式(2)中、R5及びR6はそれぞれ独立にアルキル基又はアリール基を示し、bは1~50の整数を示す。ここで、アリール基としてはフェニル基、置換フェニル基等が挙げられる。また、置換フェニル基の置換基としては、アルキル基、ビニル基、メルカプト基、アミノ基、ニトロ基、シアノ基等が挙げられる。なお、式(2)中、bが2以上の整数の場合、2個以上のR5は各々同一であっても異なっていてもよく、同様に2個以上のR6も各々同一であっても異なっていてもよい。
In the formula (2), R 5 and R 6 each independently represent an alkyl group or an aryl group, and b represents an integer of 1 to 50. Here, examples of the aryl group include a phenyl group and a substituted phenyl group. Examples of the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group. In the formula (2), when b is an integer of 2 or more, two or more R 5 may be the same or different, and similarly, two or more R 6 may be the same. May also be different.
上記の構造をエアロゲル成分としてエアロゲルの骨格中に導入することにより、例えば、従来のラダー型シルセスキオキサンに由来する構造を有する(すなわち、下記一般式(X)で表される構造を有する)エアロゲルよりも優れた柔軟性を有するエアロゲルとなる。シルセスキオキサンは、組成式:(RSiO1.5)nを有するポリシロキサンであり、カゴ型、ラダー型、ランダム型等の種々の骨格構造を有することができる。なお、下記一般式(X)にて示すように、従来のラダー型シルセスキオキサンに由来する構造を有するエアロゲルでは、橋かけ部の構造が-O-であるが、本実施形態に係るエアロゲルでは、橋かけ部の構造が上記一般式(2)で表される構造(ポリシロキサン構造)である。ただし、本態様のエアロゲルは、一般式(2)で表される構造に加え、さらにシルセスキオキサンに由来する構造を有していてもよい。
By introducing the above structure as an airgel component into the skeleton of the airgel, for example, it has a structure derived from a conventional ladder-type silsesquioxane (that is, has a structure represented by the following general formula (X)) It becomes an aerogel having better flexibility than airgel. Silsesquioxane is a polysiloxane having a composition formula: (RSiO 1.5 ) n , and can have various skeleton structures such as a cage type, a ladder type, and a random type. As shown by the following general formula (X), in the conventional aerogel having a structure derived from ladder-type silsesquioxane, the structure of the crosslinked portion is -O-, but the aerogel according to the present embodiment In the above, the structure of the crosslinked portion is a structure (polysiloxane structure) represented by the above general formula (2). However, the airgel of this embodiment may have a structure derived from silsesquioxane in addition to the structure represented by the general formula (2).
式(X)中、Rはヒドロキシ基、アルキル基又はアリール基を示す。
RIn the formula (X), R represents a hydroxy group, an alkyl group or an aryl group.
支柱部となる構造及びその鎖長、並びに橋かけ部となる構造の間隔は特に限定されないが、耐熱性と機械的強度とをより向上させるという観点から、ラダー型構造としては、下記一般式(3)で表されるラダー型構造を有していてもよい。
There is no particular limitation on the structure serving as the support portion, its chain length, and the interval between the structures serving as the bridge portions. From the viewpoint of further improving heat resistance and mechanical strength, the ladder-type structure has the following general formula ( It may have a ladder structure represented by 3).
式(3)中、R5、R6、R7及びR8はそれぞれ独立にアルキル基又はアリール基を示し、a及びcはそれぞれ独立に1~3000の整数を示し、bは1~50の整数を示す。ここで、アリール基としてはフェニル基、置換フェニル基等が挙げられる。また、置換フェニル基の置換基としては、アルキル基、ビニル基、メルカプト基、アミノ基、ニトロ基、シアノ基等が挙げられる。なお、式(3)中、bが2以上の整数の場合、2個以上のR5は各々同一であっても異なっていてもよく、同様に2個以上のR6も各々同一であっても異なっていてもよい。また、式(3)中、aが2以上の整数の場合、2個以上のR7は各々同一であっても異なっていてもよく、同様にcが2以上の整数の場合、2個以上のR8は各々同一であっても異なっていてもよい。
In the formula (3), R 5 , R 6 , R 7 and R 8 each independently represent an alkyl group or an aryl group, a and c each independently represent an integer of 1 to 3000, and b represents 1 to 50 Indicates an integer. Here, examples of the aryl group include a phenyl group and a substituted phenyl group. Examples of the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group. In addition, in Formula (3), when b is an integer of 2 or more, two or more R 5 may be the same or different, and similarly, two or more R 6 may be the same. May also be different. Further, in the formula (3), when a is an integer of 2 or more, two or more R 7 may be the same or different, and similarly, when c is an integer of 2 or more, two or more R 8 may be the same or different.
なお、より優れた柔軟性を得る観点から、式(2)及び(3)中、R5、R6、R7及びR8(ただし、R7及びR8は式(3)中のみ)としてはそれぞれ独立に炭素数が1~6のアルキル基、フェニル基等が挙げられ、当該アルキル基としてはメチル基等が挙げられる。また、式(3)中、a及びcは、それぞれ独立に6~2000とすることができるが、10~1000であってもよい。また、式(2)及び(3)中、bは、2~30とすることができるが、5~20であってもよい。
From the viewpoint of obtaining more excellent flexibility, R 5 , R 6 , R 7 and R 8 in the formulas (2) and (3) (where R 7 and R 8 are only in the formula (3)) Each independently represents an alkyl group having 1 to 6 carbon atoms, a phenyl group or the like, and the alkyl group includes a methyl group or the like. In the formula (3), a and c can each independently be 6 to 2000, but may be 10 to 1000. In the formulas (2) and (3), b may be 2 to 30, but may be 5 to 20.
また、エアロゲルの原料として、後述のシランモノマーを使用することにより、下記一般式(4)~(6)で表される構造をエアロゲルの骨格中に導入することができる。本実施形態に係るエアロゲルは、これらの構造をのうちいずれかを単独で、又は2種以上有することができる。
構造 In addition, by using a silane monomer described below as a raw material of the airgel, the structure represented by the following general formulas (4) to (6) can be introduced into the skeleton of the airgel. The airgel according to the present embodiment can have one of these structures alone or two or more of them.
式(4)中、R9はアルキル基を示す。ここで、アルキル基としては炭素数が1~6のアルキル基等が挙げられ、当該アルキル基としてはメチル基等が挙げられる。
In the formula (4), R 9 represents an alkyl group. Here, examples of the alkyl group include an alkyl group having 1 to 6 carbon atoms, and examples of the alkyl group include a methyl group.
式(5)中、R10及びR11はそれぞれ独立にアルキル基を示す。ここで、アルキル基としては炭素数が1~6のアルキル基等が挙げられ、当該アルキル基としてはメチル基等が挙げられる。
In the formula (5), R 10 and R 11 each independently represent an alkyl group. Here, examples of the alkyl group include an alkyl group having 1 to 6 carbon atoms, and examples of the alkyl group include a methyl group.
式(6)中、R12はアルキレン基を示す。ここで、アルキレン基としては炭素数が1~10のアルキレン基等が挙げられ、当該アルキレン基としてはエチレン基、ヘキシレン基等が挙げられる。
In the formula (6), R 12 represents an alkylene group. Here, examples of the alkylene group include an alkylene group having 1 to 10 carbon atoms, and examples of the alkylene group include an ethylene group and a hexylene group.
本実施形態に係るエアロゲルは、さらに強靱化する観点並びにさらに優れた断熱性及び柔軟性を達成する観点から、エアロゲル成分に加え、さらにシリカ粒子を含有していてもよい。エアロゲル成分及びシリカ粒子を含有するエアロゲルを、エアロゲル複合体ということもできる。エアロゲル複合体は、エアロゲル成分とシリカ粒子とが複合化されていながらも、エアロゲルの特徴であるクラスター構造を有しており、三次元的に微細な多孔性の構造を有していると考えられる。
エ ア The airgel according to the present embodiment may further contain silica particles in addition to the airgel component from the viewpoint of further toughening and achieving even better heat insulation and flexibility. An airgel containing an airgel component and silica particles can also be referred to as an airgel composite. The airgel composite has a cluster structure, which is a characteristic of aerogel, even though the airgel component and silica particles are composited, and is considered to have a three-dimensionally fine porous structure. .
エアロゲル成分及びシリカ粒子を含有するエアロゲルは、上述の表現に倣えば、加水分解性の官能基又は縮合性の官能基を有するケイ素化合物、及び、加水分解性の官能基を有するケイ素化合物の加水分解生成物からなる群より選択される少なくとも一種と、シリカ粒子と、を含有するゾルの縮合物である湿潤ゲルの乾燥物、ということができる。
According to the above expression, the airgel containing the airgel component and the silica particles is a silicon compound having a hydrolyzable functional group or a condensable functional group, and hydrolysis of a silicon compound having a hydrolyzable functional group. It can be said that the product is a dried product of a wet gel that is a condensate of a sol containing at least one selected from the group consisting of products and silica particles.
シリカ粒子としては、特に制限なく用いることができ、非晶質シリカ粒子等が挙げられる。非晶質シリカ粒子としては、溶融シリカ粒子、ヒュームドシリカ粒子、コロイダルシリカ粒子等が挙げられる。これらのうち、コロイダルシリカ粒子は単分散性が高く、ゾル中での凝集を抑制し易い。なお、シリカ粒子としては、中空構造、多孔質構造等を有するシリカ粒子であってもよい。
The silica particles can be used without any particular limitation, and include amorphous silica particles and the like. Examples of the amorphous silica particles include fused silica particles, fumed silica particles, and colloidal silica particles. Among these, the colloidal silica particles have high monodispersity and easily suppress aggregation in the sol. The silica particles may have a hollow structure, a porous structure, or the like.
シリカ粒子の形状は特に制限されず、球状、繭型、会合型等が挙げられる。これらのうち、シリカ粒子として球状の粒子を用いることにより、ゾル中での凝集を抑制し易くなる。シリカ粒子の平均一次粒子径は、適度な強度及び柔軟性をエアロゲルに付与し易く、乾燥時の耐収縮性に優れるエアロゲルが得易い観点から、1nm以上であってもよく、5nm以上であってもよく、20nm以上であってもよい。シリカ粒子の平均一次粒子径は、シリカ粒子の固体熱伝導を抑制し易くなり、断熱性に優れるエアロゲルが得易くなる観点から、500nm以下であってもよく、300nm以下であってもよく、100nm以下であってもよい。これらの観点から、シリカ粒子の平均一次粒子径は、1~500nmであってもよく、5~300nmであってもよく、20~100nmであってもよい。
形状 The shape of the silica particles is not particularly limited, and examples thereof include a spherical shape, a cocoon shape, and an association type. Among them, the use of spherical particles as the silica particles makes it easier to suppress aggregation in the sol. The average primary particle diameter of the silica particles is 1 nm or more, or 5 nm or more, from the viewpoint that it is easy to impart appropriate strength and flexibility to the aerogel, and to easily obtain an aerogel having excellent resistance to shrinkage during drying. And may be 20 nm or more. The average primary particle diameter of the silica particles is 500 nm or less, 300 nm or less, and 100 nm or less, from the viewpoint of easily suppressing the solid heat conduction of the silica particles and easily obtaining an aerogel having excellent heat insulating properties. The following may be used. From these viewpoints, the average primary particle diameter of the silica particles may be 1 to 500 nm, 5 to 300 nm, or 20 to 100 nm.
本実施形態において、エアロゲル成分の平均粒子径及びシリカ粒子の平均一次粒子径は、走査型電子顕微鏡(以下「SEM」と略記する。)を用いてエアロゲルを直接観察することにより得ることができる。ここでいう「直径」とは、エアロゲルの断面に露出した粒子の断面を円とみなした場合の直径を意味する。また、「断面を円とみなした場合の直径」とは、断面の面積を同じ面積の真円に置き換えたときの当該真円の直径のことである。なお、平均粒子径の算出に当たっては、100個の粒子について円の直径を求め、その平均を取るものとする。
In the present embodiment, the average particle diameter of the airgel component and the average primary particle diameter of the silica particles can be obtained by directly observing the airgel using a scanning electron microscope (hereinafter abbreviated as “SEM”). The “diameter” here means a diameter when a cross section of the particles exposed on the cross section of the airgel is regarded as a circle. The “diameter when the cross section is regarded as a circle” is the diameter of the true circle when the area of the cross section is replaced by a perfect circle having the same area. In calculating the average particle diameter, the diameter of a circle is determined for 100 particles, and the average is taken.
なお、シリカ粒子の平均粒子径は、原料からも測定することができる。例えば、二軸平均一次粒子径は、任意の粒子20個をSEMにより観察した結果から、次のようにして算出される。すなわち、通常固形分濃度が5~40質量%程度で、水中に分散しているコロイダルシリカ粒子を例にすると、コロイダルシリカ粒子の分散液に、パターン配線付きウエハを2cm角に切って得られたチップを約30秒浸した後、当該チップを純水にて約30秒間すすぎ、窒素ブロー乾燥する。その後、チップをSEM観察用の試料台に載せ、加速電圧10kVを掛け、10万倍の倍率にてシリカ粒子を観察し、画像を撮影する。得られた画像から20個のシリカ粒子を任意に選択し、それらの粒子の粒子径の平均を平均粒子径とする。
平均 The average particle size of the silica particles can also be measured from the raw material. For example, the biaxial average primary particle diameter is calculated as follows from the result of observing 20 arbitrary particles by SEM. That is, taking colloidal silica particles having a solid concentration of about 5 to 40% by mass and dispersed in water as an example, a dispersion liquid of colloidal silica particles was obtained by cutting a wafer with patterned wiring into 2 cm square. After soaking the chip for about 30 seconds, the chip is rinsed with pure water for about 30 seconds and dried with nitrogen blow. Thereafter, the chip is placed on a sample stage for SEM observation, an acceleration voltage of 10 kV is applied, and the silica particles are observed at a magnification of 100,000 and an image is taken. 20 silica particles are arbitrarily selected from the obtained image, and the average of the particle diameters of the particles is defined as the average particle diameter.
シリカ粒子の1g当たりのシラノール基数は、耐収縮性に優れるエアロゲルを得易くなる観点から、10×1018個/g以上であってもよく、50×1018個/g以上であってもよく、100×1018個/g以上であってもよい。シリカ粒子の1g当たりのシラノール基数は、均質なエアロゲルが得易くなる観点から、1000×1018個/g以下であってもよく、800×1018個/g以下であってもよく、700×1018個/g以下であってもよい。これらの観点から、シリカ粒子の1g当たりのシラノール基数は、10×1018~1000×1018個/gであってもよく、50×1018~800×1018個/gであってもよく、100×1018~700×1018個/gであってもよい。
The number of silanol groups per 1 g of the silica particles may be 10 × 10 18 / g or more, and may be 50 × 10 18 / g or more from the viewpoint of easily obtaining an aerogel having excellent shrink resistance. , 100 × 10 18 / g or more. The number of silanol groups per gram of the silica particles may be 1000 × 10 18 / g or less, 800 × 10 18 / g or less, and 700 × It may be 10 18 / g or less. From these viewpoints, the number of silanol groups per 1 g of the silica particles may be 10 × 10 18 to 1000 × 10 18 / g, or may be 50 × 10 18 to 800 × 10 18 / g. , 100 × 10 18 to 700 × 10 18 particles / g.
エアロゲル粒子の比表面積は1200m2/g以下とすることができるが、1000m2/g以下であってもよく、900m2/g以下であってもよく、800m2/g以下であってもよい。これにより、成膜性に優れる塗液を調製し易い。エアロゲル粒子の比表面積の下限は特に限定されないが、塗液中での凝集抑制及び充填率の向上という観点から、30m2/g程度とすることができる。
The specific surface area of the airgel particles can be 1200 m 2 / g or less, but may be 1000 m 2 / g or less, 900 m 2 / g or less, or 800 m 2 / g or less. . This makes it easy to prepare a coating liquid having excellent film-forming properties. The lower limit of the specific surface area of the airgel particles is not particularly limited, but may be about 30 m 2 / g from the viewpoint of suppressing aggregation in the coating liquid and improving the filling rate.
比表面積はBET法により測定することができる。測定装置としては、ガス吸着量測定装置(カンタクローム・インスツルメンツ・ジャパン合同会社製、Autosorb-iQ(Autosorbは登録商標))を用いることができる。
The specific surface area can be measured by the BET method. As a measuring device, a gas adsorption amount measuring device (Autosorb-iQ (Autosorb is a registered trademark) manufactured by Kantachrome Instruments Japan GK) can be used.
エアロゲル粒子の平均粒子径D50は1~1000μmとすることができるが、3~700μmであってもよく、5~500μmであってもよく、10~100μmであってもよく、10~50μmであってもよい。エアロゲル粒子の平均粒子径D50が1μm以上であることにより、分散性、取り扱い性等に優れるエアロゲル粒子が得易くなる。一方、平均粒子径D50が1000μm以下であることにより、分散性に優れるエアロゲル粒子が得易くなる。エアロゲル粒子の平均粒子径は、粉砕方法及び粉砕条件、ふるい、分級の仕方等により適宜調整することができる。
The average particle diameter D50 of the airgel particles may be 1 to 1000 μm, but may be 3 to 700 μm, 5 to 500 μm, 10 to 100 μm, or 10 to 50 μm. You may. When the average particle diameter D50 of the airgel particles is 1 μm or more, it becomes easy to obtain airgel particles excellent in dispersibility, handleability, and the like. On the other hand, when the average particle diameter D50 is 1000 μm or less, airgel particles having excellent dispersibility can be easily obtained. The average particle size of the airgel particles can be appropriately adjusted by a pulverizing method and pulverizing conditions, a sieving method, a classification method, and the like.
エアロゲル粒子の平均粒子径D50はレーザー回折・散乱法により測定することができる。例えば、溶媒(エタノール)に、エアロゲル粒子の含有量が0.05~5質量%となるように添加し、50Wの超音波ホモジナイザーで15~30分振動することによって、エアロゲル粒子の分散を行う。その後、分散液の約10mL程度をレーザー回折・散乱式粒子径分布測定装置に注入して、25℃で、屈折率1.3、吸収0として粒子径を測定する。そして、この粒子径分布における積算値50%(体積基準)での粒径を平均粒子径D50とする。測定装置としては、例えばMicrotrac MT3000(日機装株式会社製、製品名)を用いることができる。
平均 The average particle diameter D50 of the airgel particles can be measured by a laser diffraction / scattering method. For example, the airgel particles are added to a solvent (ethanol) so that the content of the airgel particles becomes 0.05 to 5% by mass, and the airgel particles are dispersed by vibrating for 15 to 30 minutes with a 50 W ultrasonic homogenizer. Thereafter, about 10 mL of the dispersion is injected into a laser diffraction / scattering type particle size distribution analyzer, and the particle size is measured at 25 ° C. with a refractive index of 1.3 and an absorption of 0. The particle diameter at an integrated value of 50% (by volume) in the particle diameter distribution is defined as an average particle diameter D50. As the measuring device, for example, Microtrac MT3000 (product name, manufactured by Nikkiso Co., Ltd.) can be used.
<エアロゲル粒子の製造方法>
エアロゲル粒子の製造方法は、特に限定されないが、例えば以下の方法により製造することができる。 <Method for producing airgel particles>
The method for producing the airgel particles is not particularly limited, but for example, it can be produced by the following method.
エアロゲル粒子の製造方法は、特に限定されないが、例えば以下の方法により製造することができる。 <Method for producing airgel particles>
The method for producing the airgel particles is not particularly limited, but for example, it can be produced by the following method.
本実施形態のエアロゲル粒子は、ゾル生成工程と、ゾル生成工程で得られたゾルをゲル化し、その後熟成して湿潤ゲルを得る湿潤ゲル生成工程と、湿潤ゲル生成工程で得られた湿潤ゲルを洗浄及び(必要に応じ)溶媒置換する洗浄及び溶媒置換工程と、洗浄及び溶媒置換した湿潤ゲルを乾燥する乾燥工程と、乾燥により得られたエアロゲルを粉砕する粉砕工程とを主に備える製造方法により製造することができる。
The airgel particles of the present embodiment are formed by a sol generation step, a sol obtained in the sol generation step, and a wet gel generation step of aging to obtain a wet gel, and a wet gel obtained in the wet gel generation step. A manufacturing method mainly comprising a washing and solvent replacement step of washing and (if necessary) solvent replacement, a drying step of drying the washed and solvent-replaced wet gel, and a pulverization step of pulverizing the aerogel obtained by drying. Can be manufactured.
また、ゾル生成工程と、湿潤ゲル生成工程と、湿潤ゲル生成工程で得られた湿潤ゲルを粉砕する湿潤ゲル粉砕工程と、洗浄及び溶媒置換工程と、乾燥工程とを主に備える製造方法により製造してもよい。
Also, a sol generating step, a wet gel generating step, a wet gel crushing step of crushing the wet gel obtained in the wet gel generating step, a washing and solvent replacement step, and a manufacturing method mainly comprising a drying step May be.
得られたエアロゲル粒子は、ふるい、分級等によって大きさをさらに揃えることができる。粒子の大きさを整えることで分散性を高めることができる。なお、「ゾル」とは、ゲル化反応が生じる前の状態であって、本実施形態においては、例えばケイ素化合物と、場合によりシリカ粒子と、が溶媒中に溶解又は分散している状態を意味する。また、湿潤ゲルとは、液体媒体を含んでいながらも、流動性を有しない湿潤状態のゲル固形物を意味する。
大 き The size of the obtained airgel particles can be further uniformed by sieving, classification and the like. By adjusting the size of the particles, the dispersibility can be increased. Note that the “sol” is a state before a gelation reaction occurs, and in the present embodiment, means a state in which, for example, a silicon compound and optionally silica particles are dissolved or dispersed in a solvent. I do. In addition, the wet gel refers to a gel solid in a wet state that does not have fluidity while containing a liquid medium.
(ゾル生成工程)
ゾル生成工程は、ケイ素化合物と、場合によりシリカ粒子(シリカ粒子を含む溶媒であってもよい)と、を溶媒中で混合し、必要に応じて加水分解反応を行う工程である。より具体的には、ゾル生成工程は、加水分解性の官能基を有するケイ素化合物、縮合性の官能基を有するケイ素化合物、加水分解性の官能基を有するケイ素化合物を加水分解してなる加水分解生成物等を含むゾルを生成する工程である。ゾル生成工程は、加水分解性の官能基又は縮合性の官能基を有するケイ素化合物、及び、加水分解性の官能基を有するケイ素化合物の加水分解生成物からなる群より選択される少なくとも一種、を含有するゾルを生成する工程であるということもできる。上記に例示したエアロゲルは、このようなゾルから生成された湿潤ゲルを乾燥することで得ることができる。 (Sol generation step)
The sol generation step is a step of mixing a silicon compound and, in some cases, silica particles (may be a solvent containing silica particles) in a solvent and performing a hydrolysis reaction as necessary. More specifically, the sol generation step includes a hydrolysis of a silicon compound having a hydrolyzable functional group, a silicon compound having a condensable functional group, and a silicon compound having a hydrolyzable functional group. This is a step of producing a sol containing a product or the like. The sol generation step includes a silicon compound having a hydrolyzable functional group or a condensable functional group, and at least one selected from the group consisting of hydrolysis products of the silicon compound having a hydrolyzable functional group. It can be said that this is a step of producing a sol to be contained. The aerogel exemplified above can be obtained by drying a wet gel generated from such a sol.
ゾル生成工程は、ケイ素化合物と、場合によりシリカ粒子(シリカ粒子を含む溶媒であってもよい)と、を溶媒中で混合し、必要に応じて加水分解反応を行う工程である。より具体的には、ゾル生成工程は、加水分解性の官能基を有するケイ素化合物、縮合性の官能基を有するケイ素化合物、加水分解性の官能基を有するケイ素化合物を加水分解してなる加水分解生成物等を含むゾルを生成する工程である。ゾル生成工程は、加水分解性の官能基又は縮合性の官能基を有するケイ素化合物、及び、加水分解性の官能基を有するケイ素化合物の加水分解生成物からなる群より選択される少なくとも一種、を含有するゾルを生成する工程であるということもできる。上記に例示したエアロゲルは、このようなゾルから生成された湿潤ゲルを乾燥することで得ることができる。 (Sol generation step)
The sol generation step is a step of mixing a silicon compound and, in some cases, silica particles (may be a solvent containing silica particles) in a solvent and performing a hydrolysis reaction as necessary. More specifically, the sol generation step includes a hydrolysis of a silicon compound having a hydrolyzable functional group, a silicon compound having a condensable functional group, and a silicon compound having a hydrolyzable functional group. This is a step of producing a sol containing a product or the like. The sol generation step includes a silicon compound having a hydrolyzable functional group or a condensable functional group, and at least one selected from the group consisting of hydrolysis products of the silicon compound having a hydrolyzable functional group. It can be said that this is a step of producing a sol to be contained. The aerogel exemplified above can be obtained by drying a wet gel generated from such a sol.
ケイ素化合物としては、ポリシロキサン化合物を用いることができる。すなわち、上記ゾルは、加水分解性の官能基又は縮合性の官能基を有するポリシロキサン化合物、及び、加水分解性の官能基を有するポリシロキサン化合物の加水分解生成物からなる群より選択される少なくとも一種の化合物(以下、場合により「ポリシロキサン化合物群」という)を含有することができる。
ポ リ A polysiloxane compound can be used as the silicon compound. That is, the sol is at least selected from the group consisting of a polysiloxane compound having a hydrolyzable functional group or a condensable functional group, and a hydrolysis product of a polysiloxane compound having a hydrolyzable functional group. One kind of compound (hereinafter, sometimes referred to as “polysiloxane compound group”) may be contained.
ポリシロキサン化合物における官能基は、特に限定されないが、同じ官能基同士で反応するか、あるいは他の官能基と反応する基とすることができる。加水分解性の官能基としては、アルコキシ基が挙げられる。縮合性の官能基としては、水酸基、シラノール基、カルボキシル基、フェノール性水酸基等が挙げられる。水酸基は、ヒドロキシアルキル基等の水酸基含有基に含まれていてもよい。なお、加水分解性の官能基又は縮合性の官能基を有するポリシロキサン化合物は、加水分解性の官能基及び縮合性の官能基とは異なる反応性基(加水分解性の官能基及び縮合性の官能基に該当しない官能基)をさらに有していてもよい。反応性基としては、エポキシ基、メルカプト基、グリシドキシ基、ビニル基、アクリロイル基、メタクリロイル基、アミノ基等が挙げられる。エポキシ基は、グリシドキシ基等のエポキシ基含有基に含まれていてもよい。これらの官能基及び反応性基を有するポリシロキサン化合物は単独で、又は2種類以上を混合して用いてもよい。これらの官能基及び反応性基のうち、例えば、エアロゲルの柔軟性を向上する基としては、アルコキシ基、シラノール基、ヒドロキシアルキル基等が挙げられ、これらのうち、アルコキシ基及びヒドロキシアルキル基は、ゾルの相溶性をより向上することができる。また、ポリシロキサン化合物の反応性の向上とエアロゲルの熱伝導率の低減の観点から、アルコキシ基及びヒドロキシアルキル基の炭素数は1~6とすることができるが、エアロゲルの柔軟性をより向上する観点から2~4であってもよい。
The functional group in the polysiloxane compound is not particularly limited, but may be a group that reacts with the same functional group or a group that reacts with another functional group. Examples of the hydrolyzable functional group include an alkoxy group. Examples of the condensable functional group include a hydroxyl group, a silanol group, a carboxyl group, and a phenolic hydroxyl group. The hydroxyl group may be contained in a hydroxyl group-containing group such as a hydroxyalkyl group. Note that a polysiloxane compound having a hydrolyzable functional group or a condensable functional group is a reactive group different from the hydrolyzable functional group and the condensable functional group (the hydrolyzable functional group and the condensable functional group). Functional group which does not correspond to a functional group). Examples of the reactive group include an epoxy group, a mercapto group, a glycidoxy group, a vinyl group, an acryloyl group, a methacryloyl group, and an amino group. The epoxy group may be contained in an epoxy group-containing group such as a glycidoxy group. These polysiloxane compounds having a functional group and a reactive group may be used alone or as a mixture of two or more. Among these functional groups and reactive groups, for example, groups that improve the flexibility of the airgel include alkoxy groups, silanol groups, hydroxyalkyl groups, and the like. Among these, alkoxy groups and hydroxyalkyl groups are: The compatibility of the sol can be further improved. Further, from the viewpoint of improving the reactivity of the polysiloxane compound and reducing the thermal conductivity of the aerogel, the number of carbon atoms of the alkoxy group and the hydroxyalkyl group can be 1 to 6, but the flexibility of the aerogel is further improved. From the viewpoint, it may be 2 to 4.
分子内にヒドロキシアルキル基を有するポリシロキサン化合物としては、下記一般式(A)で表される構造を有するものが挙げられる。下記一般式(A)で表される構造を有するポリシロキサン化合物を使用することにより、一般式(1)及び式(1a)で表される構造をエアロゲルの骨格中に導入することができる。
Examples of the polysiloxane compound having a hydroxyalkyl group in the molecule include those having a structure represented by the following general formula (A). By using a polysiloxane compound having a structure represented by the following general formula (A), the structures represented by the general formulas (1) and (1a) can be introduced into the skeleton of the airgel.
式(A)中、R1aはヒドロキシアルキル基を示し、R2aはアルキレン基を示し、R3a及びR4aはそれぞれ独立にアルキル基又はアリール基を示し、nは1~50の整数を示す。ここで、アリール基としてはフェニル基、置換フェニル基等が挙げられる。また、置換フェニル基の置換基としては、アルキル基、ビニル基、メルカプト基、アミノ基、ニトロ基、シアノ基等が挙げられる。なお、式(A)中、2個のR1aは各々同一であっても異なっていてもよく、同様に2個のR2aは各々同一であっても異なっていてもよい。また、式(A)中、2個以上のR3aは各々同一であっても異なっていてもよく、同様に2個以上のR4aは各々同一であっても異なっていてもよい。
In the formula (A), R 1a represents a hydroxyalkyl group, R 2a represents an alkylene group, R 3a and R 4a each independently represent an alkyl group or an aryl group, and n represents an integer of 1 to 50. Here, examples of the aryl group include a phenyl group and a substituted phenyl group. Examples of the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group. In the formula (A), two R 1a may be the same or different, and similarly, two R 2a may be the same or different. In the formula (A), two or more R 3a may be the same or different, and similarly, two or more R 4a may be the same or different.
上記構造のポリシロキサン化合物を含有するゾルの縮合物である(ゾルから生成された)湿潤ゲルを用いることにより、低熱伝導率かつ柔軟なエアロゲルをさらに得易くなる。このような観点から、式(A)中、R1aとしては炭素数が1~6のヒドロキシアルキル基等が挙げられ、当該ヒドロキシアルキル基としてはヒドロキシエチル基、ヒドロキシプロピル基等が挙げられる。また、式(A)中、R2aとしては炭素数が1~6のアルキレン基等が挙げられ、当該アルキレン基としてはエチレン基、プロピレン基等が挙げられる。また、式(A)中、R3a及びR4aとしてはそれぞれ独立に炭素数が1~6のアルキル基、フェニル基等が挙げられ、当該アルキル基としてはメチル基等が挙げられる。また、式(A)中、nは2~30とすることができるが、5~20であってもよい。
By using a wet gel (formed from the sol) which is a condensate of a sol containing the polysiloxane compound having the above structure, it becomes easier to obtain a flexible aerogel having low thermal conductivity. From such a viewpoint, in the formula (A), R 1a includes a hydroxyalkyl group having 1 to 6 carbon atoms and the like, and the hydroxyalkyl group includes a hydroxyethyl group and a hydroxypropyl group. In Formula (A), R 2a includes an alkylene group having 1 to 6 carbon atoms, and the alkylene group includes an ethylene group, a propylene group, and the like. In the formula (A), R 3a and R 4a each independently include an alkyl group having 1 to 6 carbon atoms, a phenyl group and the like, and the alkyl group includes a methyl group and the like. In the formula (A), n can be 2 to 30, but may be 5 to 20.
上記一般式(A)で表される構造を有するポリシロキサン化合物としては、市販品を用いることができ、X-22-160AS、KF-6001、KF-6002、KF-6003等の化合物(いずれも、信越化学工業株式会社製)、XF42-B0970、Fluid OFOH 702-4%等の化合物(いずれも、モメンティブ・パフォーマンス・マテリアルズ・ジャパン合同会社製)などが挙げられる。
As the polysiloxane compound having the structure represented by the general formula (A), commercially available products can be used, and compounds such as X-22-160AS, KF-6001, KF-6002, and KF-6003 (all of which are shown below) can be used. And Shin-Etsu Chemical Co., Ltd.), and compounds such as XF42-B0970 and Fluid {OFOH} 702-4% (all manufactured by Momentive Performance Materials Japan GK).
分子内にアルコキシ基を有するポリシロキサン化合物としては、下記一般式(B)で表される構造を有するものが挙げられる。下記一般式(B)で表される構造を有するポリシロキサン化合物を使用することにより、一般式(2)又は(3)で表される橋かけ部を有するラダー型構造をエアロゲルの骨格中に導入することができる。
Examples of the polysiloxane compound having an alkoxy group in a molecule include those having a structure represented by the following general formula (B). By using a polysiloxane compound having a structure represented by the following general formula (B), a ladder-type structure having a crosslinked portion represented by the general formula (2) or (3) is introduced into the skeleton of the airgel. can do.
式(B)中、R1bはアルキル基、アルコキシ基又はアリール基を示し、R2b及びR3bはそれぞれ独立にアルコキシ基を示し、R4b及びR5bはそれぞれ独立にアルキル基又はアリール基を示し、mは1~50の整数を示す。ここで、アリール基としてはフェニル基、置換フェニル基等が挙げられる。また、置換フェニル基の置換基としては、アルキル基、ビニル基、メルカプト基、アミノ基、ニトロ基、シアノ基等が挙げられる。なお、式(B)中、2個のR1bは各々同一であっても異なっていてもよく、2個のR2bは各々同一であっても異なっていてもよく、同様に2個のR3bは各々同一であっても異なっていてもよい。また、式(B)中、mが2以上の整数の場合、2個以上のR4bは各々同一であっても異なっていてもよく、同様に2個以上のR5bも各々同一であっても異なっていてもよい。
In the formula (B), R 1b represents an alkyl group, an alkoxy group or an aryl group, R 2b and R 3b each independently represent an alkoxy group, and R 4b and R 5b each independently represent an alkyl group or an aryl group. , M represents an integer of 1 to 50. Here, examples of the aryl group include a phenyl group and a substituted phenyl group. Examples of the substituent of the substituted phenyl group include an alkyl group, a vinyl group, a mercapto group, an amino group, a nitro group, and a cyano group. In the formula (B), two R 1b may be the same or different, and two R 2b may be the same or different, respectively. 3b may be the same or different. In the formula (B), when m is an integer of 2 or more, two or more R 4b may be the same or different, and similarly, two or more R 5b may be the same. May also be different.
上記構造のポリシロキサン化合物又はその加水分解生成物を含有するゾルの縮合物である(ゾルから生成された)湿潤ゲルを用いることにより、低熱伝導率かつ柔軟なエアロゲルをさらに得易くなる。このような観点から、式(B)中、R1bとしては炭素数が1~6のアルキル基、炭素数が1~6のアルコキシ基等が挙げられ、当該アルキル基又はアルコキシ基としてはメチル基、メトキシ基、エトキシ基等が挙げられる。また、式(B)中、R2b及びR3bとしてはそれぞれ独立に炭素数が1~6のアルコキシ基等が挙げられ、当該アルコキシ基としてはメトキシ基、エトキシ基等が挙げられる。また、式(B)中、R4b及びR5bとしてはそれぞれ独立に炭素数が1~6のアルキル基、フェニル基等が挙げられ、当該アルキル基としてはメチル基等が挙げられる。また、式(B)中、mは2~30とすることができるが、5~20であってもよい。
By using a wet gel (generated from the sol), which is a condensate of a sol containing the polysiloxane compound having the above structure or a hydrolysis product thereof, a soft aerogel having a low thermal conductivity and a low thermal conductivity can be more easily obtained. From such a viewpoint, in the formula (B), R 1b includes an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and the like, and the alkyl group or the alkoxy group is a methyl group. Methoxy group, ethoxy group and the like. In the formula (B), R 2b and R 3b each independently include an alkoxy group having 1 to 6 carbon atoms, and the alkoxy group includes a methoxy group and an ethoxy group. In formula (B), R 4b and R 5b each independently include an alkyl group having 1 to 6 carbon atoms, a phenyl group and the like, and the alkyl group includes a methyl group and the like. In the formula (B), m can be 2 to 30, but may be 5 to 20.
上記一般式(B)で表される構造を有するポリシロキサン化合物は、特開2000-26609号公報、特開2012-233110号公報等にて報告される製造方法を適宜参照して得ることができる。
The polysiloxane compound having the structure represented by the general formula (B) can be obtained by appropriately referring to the production methods reported in JP-A-2000-26609, JP-A-2012-233110, and the like. .
なお、アルコキシ基は加水分解するため、アルコキシ基を有するポリシロキサン化合物はゾル中にて加水分解生成物として存在する可能性があり、アルコキシ基を有するポリシロキサン化合物とその加水分解生成物は混在していてもよい。また、アルコキシ基を有するポリシロキサン化合物において、分子中のアルコキシ基の全てが加水分解されていてもよいし、部分的に加水分解されていてもよい。
Since the alkoxy group hydrolyzes, the polysiloxane compound having the alkoxy group may be present as a hydrolysis product in the sol, and the polysiloxane compound having the alkoxy group and the hydrolysis product are mixed. May be. In the polysiloxane compound having an alkoxy group, all of the alkoxy groups in the molecule may be hydrolyzed or partially hydrolyzed.
これら、加水分解性の官能基又は縮合性の官能基を有するポリシロキサン化合物、及び、加水分解性の官能基を有するポリシロキサン化合物の加水分解生成物は、単独で、又は2種類以上を混合して用いてもよい。
These polysiloxane compounds having a hydrolyzable functional group or a condensable functional group, and hydrolysis products of a polysiloxane compound having a hydrolyzable functional group may be used alone or as a mixture of two or more. May be used.
本実施形態に係るエアロゲルを作製するにあたり、ケイ素化合物としては、上述のポリシロキサン化合物以外のケイ素化合物を用いることができる。そのようなケイ素化合物としてはシランモノマーが挙げられる。すなわち、上記のケイ素化合物を含有するゾルは、加水分解性の官能基又は縮合性の官能基を有するシランモノマー、及び、加水分解性の官能基を有する当該シランモノマーの加水分解生成物からなる群より選択される少なくとも一種(以下、場合により「シランモノマー群」という)を、上述のポリシロキサン化合物群に加えて、あるいは上述のポリシロキサン化合物群に代えて、含有することができる。シランモノマーにおける分子内のケイ素数は1~6とすることができる。
作 製 In producing the airgel according to the present embodiment, a silicon compound other than the above-described polysiloxane compound can be used as the silicon compound. Such silicon compounds include silane monomers. That is, the sol containing the silicon compound is a group consisting of a silane monomer having a hydrolyzable functional group or a condensable functional group, and a hydrolysis product of the silane monomer having a hydrolyzable functional group. At least one selected from the following (hereinafter sometimes referred to as “silane monomer group”) may be contained in addition to the above-mentioned polysiloxane compound group or in place of the above-mentioned polysiloxane compound group. The number of silicon atoms in the molecule of the silane monomer can be 1 to 6.
加水分解性の官能基を有するシランモノマーとしては、特に限定されないが、アルキルケイ素アルコキシド等が挙げられる。アルキルケイ素アルコキシドは、耐水性を向上する観点から、加水分解性の官能基の数を3個以下とすることができる。このようなアルキルケイ素アルコキシドとしては、モノアルキルトリアルコキシシラン、モノアルキルジアルコキシシラン、ジアルキルジアルコキシシラン、モノアルキルモノアルコキシシラン、ジアルキルモノアルコキシシラン、トリアルキルモノアルコキシシラン等が挙げられ、具体的には、メチルトリメトキシシラン、メチルジメトキシシラン、ジメチルジエトキシシラン、ジメチルジメトキシシラン、エチルトリメトキシシラン、ヘキシルトリメトキシシラン等が挙げられる。ここで、加水分解性の官能基としては、メトキシ基、エトキシ基等のアルコキシ基などが挙げられる。
シ ラ ン The silane monomer having a hydrolyzable functional group is not particularly limited, and examples thereof include an alkyl silicon alkoxide. Alkyl silicon alkoxides can reduce the number of hydrolyzable functional groups to three or less from the viewpoint of improving water resistance. Examples of such an alkyl silicon alkoxide include monoalkyl trialkoxy silane, monoalkyl dialkoxy silane, dialkyl dialkoxy silane, monoalkyl monoalkoxy silane, dialkyl monoalkoxy silane, and trialkyl monoalkoxy silane. Examples thereof include methyltrimethoxysilane, methyldimethoxysilane, dimethyldiethoxysilane, dimethyldimethoxysilane, ethyltrimethoxysilane, hexyltrimethoxysilane and the like. Here, examples of the hydrolyzable functional group include an alkoxy group such as a methoxy group and an ethoxy group.
縮合性の官能基を有するシランモノマーとしては、特に限定されないが、シランテトラオール、メチルシラントリオール、ジメチルシランジオール、フェニルシラントリオール、フェニルメチルシランジオール、ジフェニルシランジオール、n-プロピルシラントリオール、ヘキシルシラントリオール、オクチルシラントリオール、デシルシラントリオール、トリフルオロプロピルシラントリオール等が挙げられる。
The silane monomer having a condensable functional group is not particularly limited, but includes silanetetraol, methylsilanetriol, dimethylsilanediol, phenylsilanetriol, phenylmethylsilanediol, diphenylsilanediol, n-propylsilanetriol, hexylsilane Triol, octylsilanetriol, decylsilanetriol, trifluoropropylsilanetriol and the like can be mentioned.
シランモノマーは、加水分解性の官能基及び縮合性の官能基とは異なる上述の反応性基(加水分解性の官能基及び縮合性の官能基に該当しない官能基)をさらに有していてもよい。
Even if the silane monomer further has the above-mentioned reactive group (functional group which does not correspond to the hydrolyzable functional group and the condensable functional group) different from the hydrolyzable functional group and the condensable functional group, Good.
加水分解性の官能基及び反応性基を有するシランモノマーとして、ビニルトリメトキシシラン、3-グリシドキシプロピルトリメトキシシラン、3-グリシドキシプロピルメチルジメトキシシラン、3-メタクリロキシプロピルトリメトキシシラン、3-メタクリロキシプロピルメチルジメトキシシラン、3-アクリロキシプロピルトリメトキシシラン、3-メルカプトプロピルトリメトキシシラン、3-メルカプトプロピルメチルジメトキシシラン、N-フェニル-3-アミノプロピルトリメトキシシラン、N-2-(アミノエチル)-3-アミノプロピルメチルジメトキシシラン等も用いることができる。
Examples of the silane monomer having a hydrolyzable functional group and a reactive group include vinyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropylmethyldimethoxysilane, N-phenyl-3-aminopropyltrimethoxysilane, N-2- (Aminoethyl) -3-aminopropylmethyldimethoxysilane and the like can also be used.
縮合性の官能基及び反応性基を有するシランモノマーとして、ビニルシラントリオール、3-グリシドキシプロピルシラントリオール、3-グリシドキシプロピルメチルシランジオール、3-メタクリロキシプロピルシラントリオール、3-メタクリロキシプロピルメチルシランジオール、3-アクリロキシプロピルシラントリオール、3-メルカプトプロピルシラントリオール、3-メルカプトプロピルメチルシランジオール、N-フェニル-3-アミノプロピルシラントリオール、N-2-(アミノエチル)-3-アミノプロピルメチルシランジオール等も用いることができる。
Examples of silane monomers having a condensable functional group and a reactive group include vinyl silane triol, 3-glycidoxypropyl silane triol, 3-glycidoxy propyl methyl silane diol, 3-methacryloxy propyl silane triol, and 3-methacryloxy propyl Methylsilanediol, 3-acryloxypropylsilanetriol, 3-mercaptopropylsilanetriol, 3-mercaptopropylmethylsilanediol, N-phenyl-3-aminopropylsilanetriol, N-2- (aminoethyl) -3-amino Propylmethylsilanediol and the like can also be used.
シランモノマーは2以上のケイ素原子を有していてもよく、ビストリメトキシシリルメタン、ビストリメトキシシリルエタン、ビストリメトキシシリルヘキサン等も用いることができる。
The silane monomer may have two or more silicon atoms, and bistrimethoxysilylmethane, bistrimethoxysilylethane, bistrimethoxysilylhexane and the like can also be used.
加水分解性の官能基又は縮合性の官能基を有するシランモノマー、及び、加水分解性の官能基を有する当該シランモノマーの加水分解生成物は、単独で、又は2種類以上を混合して用いてもよい。
A silane monomer having a hydrolyzable functional group or a condensable functional group, and a hydrolysis product of the silane monomer having a hydrolyzable functional group may be used alone or as a mixture of two or more. Is also good.
エアロゲルがさらにシリカ粒子を含む場合は、ゾル生成工程は、加水分解性の官能基又は縮合性の官能基を有するケイ素化合物、及び、加水分解性の官能基を有するケイ素化合物の加水分解生成物からなる群より選択される少なくとも一種と、シリカ粒子と、を含有するゾルを生成する工程であるということができる。
When the airgel further contains silica particles, the sol generation step is a silicon compound having a hydrolyzable functional group or a condensable functional group, and a hydrolysis product of a silicon compound having a hydrolyzable functional group. It can be said that this is a step of generating a sol containing at least one selected from the group and silica particles.
上記ゾルに含まれるポリシロキサン化合物群の含有量(加水分解性の官能基又は縮合性の官能基を有するポリシロキサン化合物の含有量、及び、加水分解性の官能基を有するポリシロキサン化合物の加水分解生成物の含有量の総和)は、良好な反応性をさらに得易くなる観点から、ゾルの総量100質量部に対し、5質量部以上であってもよく、10質量部以上であってもよい。上記ゾルに含まれるポリシロキサン化合物群の含有量は、良好な相溶性をさらに得易くなる観点から、ゾルの総量100質量部に対し、50質量部以下であってもよく、30質量部以下であってもよい。これらの観点から、上記ゾルに含まれるポリシロキサン化合物群の含有量は、ゾルの総量100質量部に対し、5~50質量部であってもよく、10~30質量部であってもよい。
The content of the polysiloxane compound group contained in the sol (the content of the polysiloxane compound having a hydrolyzable functional group or a condensable functional group, and the hydrolysis of the polysiloxane compound having a hydrolyzable functional group) The sum of the contents of the products) may be 5 parts by mass or more, or 10 parts by mass or more with respect to 100 parts by mass of the total amount of the sol, from the viewpoint of more easily obtaining good reactivity. . The content of the polysiloxane compound group contained in the sol may be 50 parts by mass or less with respect to 100 parts by mass of the total amount of the sol, from the viewpoint of making it easier to obtain good compatibility. There may be. From these viewpoints, the content of the polysiloxane compound group contained in the sol may be 5 to 50 parts by mass or 10 to 30 parts by mass based on 100 parts by mass of the total amount of the sol.
上記ゾルがシランモノマーを含有する場合、シランモノマー群の含有量(加水分解性の官能基又は縮合性の官能基を有するシランモノマーの含有量、及び、加水分解性の官能基を有するシランモノマーの加水分解生成物の含有量の総和)は、良好な反応性をさらに得易くなる観点から、ゾルの総量100質量部に対し、5質量部以上であってもよく、10質量部以上であってもよい。上記ゾルに含まれるシランモノマー群の含有量は、良好な相溶性をさらに得易くなる観点から、ゾルの総量100質量部に対し、50質量部以下であってもよく、30質量部以下であってもよい。これらの観点から、上記ゾルに含まれるシランモノマー群の含有量は、5~50質量部であってもよく、10~30質量部であってもよい。
When the sol contains a silane monomer, the content of the silane monomer group (the content of the silane monomer having a hydrolyzable functional group or a condensable functional group, and the content of the silane monomer having a hydrolyzable functional group) The sum of the contents of the hydrolysis products) may be 5 parts by mass or more, or 10 parts by mass or more with respect to 100 parts by mass of the total amount of the sol, from the viewpoint of further obtaining good reactivity. Is also good. The content of the silane monomer group contained in the sol may be 50 parts by mass or less, or 30 parts by mass or less, based on 100 parts by mass of the total amount of the sol, from the viewpoint of further obtaining good compatibility. May be. From these viewpoints, the content of the silane monomer group contained in the sol may be 5 to 50 parts by mass, or may be 10 to 30 parts by mass.
ゾルが、ポリシロキサン化合物群及びシランモノマー群を共に含む場合、ポリシロキサン化合物群の含有量と、シランモノマー群の含有量との比は、良好な相溶性がさらに得易くなる観点から、1:0.5以上であってもよく、1:1以上であってもよい。ポリシロキサン化合物群の含有量と、シランモノマー群の含有量との比は、ゲルの収縮がさらに抑制し易くなる観点から、1:4以下であってもよく、1:2以下であってもよい。これらの観点から、ポリシロキサン化合物群の含有量と、シランモノマー群の含有量との比は、1:0.5~1:4であってもよく、1:1~1:2であってもよい。
When the sol contains both the polysiloxane compound group and the silane monomer group, the ratio between the content of the polysiloxane compound group and the content of the silane monomer group is preferably 1: from the viewpoint that good compatibility is more easily obtained. It may be 0.5 or more, or 1: 1 or more. The ratio between the content of the polysiloxane compound group and the content of the silane monomer group may be 1: 4 or less, or 1: 2 or less, from the viewpoint of further suppressing gel shrinkage. Good. From these viewpoints, the ratio of the content of the polysiloxane compound group to the content of the silane monomer group may be from 1: 0.5 to 1: 4, and may be from 1: 1 to 1: 2. Is also good.
上記ゾルにシリカ粒子が含まれる場合、シリカ粒子の含有量は、適度な強度をエアロゲルに付与し易くなり、乾燥時の耐収縮性に優れるエアロゲルが得易くなる観点から、ゾルの総量100質量部に対し、1質量部以上であってもよく、4質量部以上であってもよい。シリカ粒子の含有量は、シリカ粒子の固体熱伝導を抑制し易くなり、断熱性に優れるエアロゲルが得易くなる観点から、ゾルの総量100質量部に対し、20質量部以下であってもよく、15質量部以下であってもよい。これらの観点から、シリカ粒子の含有量は、ゾルの総量100質量部に対し、1~20質量部であってもよく、4~15質量部であってもよい。
When silica particles are contained in the sol, the content of the silica particles makes it easy to impart appropriate strength to the aerogel, and from the viewpoint of easily obtaining an aerogel having excellent shrink resistance during drying, the total amount of the sol is 100 parts by mass. On the other hand, it may be 1 part by mass or more, or 4 parts by mass or more. The content of the silica particles is easy to suppress the solid heat conduction of the silica particles, and from the viewpoint of easily obtaining an aerogel having excellent heat insulating properties, the total amount of the sol may be 20 parts by mass or less based on 100 parts by mass of the sol, It may be 15 parts by mass or less. From these viewpoints, the content of the silica particles may be 1 to 20 parts by mass or 4 to 15 parts by mass with respect to 100 parts by mass of the total amount of the sol.
ゾル生成工程では、ケイ素化合物の混合及び場合により加水分解のために溶媒が用いられる。溶媒としては、例えば、水、又は、水及びアルコールの混合液を用いることができる。アルコールとしては、メタノール、エタノール、n-プロパノール、2-プロパノール、n-ブタノール、2-ブタノール、t-ブタノール等が挙げられる。これらの中でも、ゲル壁との界面張力を低減させる点で、表面張力が低くかつ沸点の低いアルコールとしては、メタノール、エタノール、2-プロパノール等が挙げられる。これらは単独で、又は2種類以上を混合して用いてもよい。
溶媒 In the sol generation step, a solvent is used for mixing and possibly hydrolyzing the silicon compound. As the solvent, for example, water or a mixture of water and alcohol can be used. Examples of the alcohol include methanol, ethanol, n-propanol, 2-propanol, n-butanol, 2-butanol, t-butanol and the like. Among these, examples of the alcohol having a low surface tension and a low boiling point in terms of reducing the interfacial tension with the gel wall include methanol, ethanol, and 2-propanol. These may be used alone or as a mixture of two or more.
例えば溶媒としてアルコールを用いる場合、アルコールの量は、ポリシロキサン化合物群及びシランモノマー群の総量1モルに対し、4~8モルとすることができるが、4~6.5であってもよく、又は4.5~6モルであってもよい。アルコールの量を4モル以上にすることにより良好な相溶性をさらに得易くなり、また、8モル以下にすることによりゲルの収縮をさらに抑制し易くなる。
For example, when an alcohol is used as the solvent, the amount of the alcohol can be 4 to 8 mol, or 4 to 6.5 mol per 1 mol of the total amount of the polysiloxane compound group and the silane monomer group. Alternatively, it may be 4.5 to 6 mol. By setting the amount of the alcohol to 4 mol or more, it becomes easier to obtain good compatibility, and to set the amount to 8 mol or less, the shrinkage of the gel is more easily suppressed.
また溶媒には、加水分解反応を促進させるための酸触媒が含まれていてもよい。酸触媒としては、フッ酸、塩酸、硝酸、硫酸、亜硫酸、リン酸、亜リン酸、次亜リン酸、臭素酸、塩素酸、亜塩素酸、次亜塩素酸等の無機酸;酸性リン酸アルミニウム、酸性リン酸マグネシウム、酸性リン酸亜鉛等の酸性リン酸塩;酢酸、ギ酸、プロピオン酸、シュウ酸、マロン酸、コハク酸、クエン酸、リンゴ酸、アジピン酸、アゼライン酸等の有機カルボン酸などが挙げられる。これらの中でも、得られるエアロゲルの耐水性をより向上する酸触媒としては有機カルボン酸が挙げられる。当該有機カルボン酸としては酢酸が挙げられるが、ギ酸、プロピオン酸、シュウ酸、マロン酸等であってもよい。これらは単独で、又は2種類以上を混合して用いてもよい。
Also, the solvent may contain an acid catalyst for promoting the hydrolysis reaction. Examples of the acid catalyst include inorganic acids such as hydrofluoric acid, hydrochloric acid, nitric acid, sulfuric acid, sulfurous acid, phosphoric acid, phosphorous acid, hypophosphorous acid, bromic acid, chloric acid, chlorous acid, and hypochlorous acid; Acid phosphates such as aluminum, magnesium acid phosphate and zinc acid phosphate; organic carboxylic acids such as acetic acid, formic acid, propionic acid, oxalic acid, malonic acid, succinic acid, citric acid, malic acid, adipic acid and azelaic acid And the like. Among these, an organic carboxylic acid is mentioned as an acid catalyst for further improving the water resistance of the obtained airgel. Examples of the organic carboxylic acid include acetic acid, and may be formic acid, propionic acid, oxalic acid, malonic acid, and the like. These may be used alone or as a mixture of two or more.
酸触媒を用いることで、ケイ素化合物の加水分解反応を促進させて、より短時間でゾルを得ることができる。
By using a diacid catalyst, the hydrolysis reaction of the silicon compound is promoted, and a sol can be obtained in a shorter time.
酸触媒の添加量は、ポリシロキサン化合物群及びシランモノマー群の総量100質量部に対し、0.001~0.1質量部とすることができる。
The amount of the acid catalyst can be 0.001 to 0.1 part by mass based on 100 parts by mass of the total of the polysiloxane compound group and the silane monomer group.
また、特許第5250900号公報に示されるように、溶媒中に界面活性剤、熱加水分解性化合物等を添加することもできる。
界面 Also, as disclosed in Japanese Patent No. 5250900, a surfactant, a thermally hydrolyzable compound, and the like can be added to a solvent.
界面活性剤としては、非イオン性界面活性剤、イオン性界面活性剤等を用いることができる。これらは単独で、又は2種類以上を混合して用いてもよい。
非 As the surfactant, a nonionic surfactant, an ionic surfactant or the like can be used. These may be used alone or as a mixture of two or more.
非イオン性界面活性剤としては、例えば、ポリオキシエチレン等の親水部と主にアルキル基からなる疎水部とを含む化合物、ポリオキシプロピレン等の親水部を含む化合物などを使用できる。ポリオキシエチレン等の親水部と主にアルキル基からなる疎水部とを含む化合物としては、ポリオキシエチレンノニルフェニルエーテル、ポリオキシエチレンオクチルフェニルエーテル、ポリオキシエチレンアルキルエーテル等が挙げられる。ポリオキシプロピレン等の親水部を含む化合物としては、ポリオキシプロピレンアルキルエーテル、ポリオキシエチレンとポリオキシプロピレンのブロック共重合体等が挙げられる。
As the nonionic surfactant, for example, a compound containing a hydrophilic part such as polyoxyethylene and a hydrophobic part mainly composed of an alkyl group, a compound containing a hydrophilic part such as polyoxypropylene and the like can be used. Examples of the compound containing a hydrophilic part such as polyoxyethylene and a hydrophobic part mainly composed of an alkyl group include polyoxyethylene nonyl phenyl ether, polyoxyethylene octyl phenyl ether, polyoxyethylene alkyl ether and the like. Examples of the compound containing a hydrophilic portion, such as polyoxypropylene, include polyoxypropylene alkyl ether, a block copolymer of polyoxyethylene and polyoxypropylene, and the like.
イオン性界面活性剤としては、カチオン性界面活性剤、アニオン性界面活性剤、両イオン性界面活性剤等が挙げられる。カチオン性界面活性剤としては、臭化セチルトリメチルアンモニウム、塩化セチルトリメチルアンモニウム等が挙げられ、アニオン性界面活性剤としては、ドデシルスルホン酸ナトリウム等が挙げられる。また、両イオン性界面活性剤としては、アミノ酸系界面活性剤、ベタイン系界面活性剤、アミンオキシド系界面活性剤等が挙げられる。アミノ酸系界面活性剤としては、例えば、アシルグルタミン酸等が挙げられる。ベタイン系界面活性剤としては、例えば、ラウリルジメチルアミノ酢酸ベタイン、ステアリルジメチルアミノ酢酸ベタイン等が挙げられる。アミンオキシド系界面活性剤としては、例えばラウリルジメチルアミンオキシドが挙げられる。
Examples of the ionic surfactant include a cationic surfactant, an anionic surfactant, and an amphoteric surfactant. Examples of the cationic surfactant include cetyltrimethylammonium bromide and cetyltrimethylammonium chloride, and examples of the anionic surfactant include sodium dodecylsulfonate. In addition, examples of the amphoteric surfactant include an amino acid-based surfactant, a betaine-based surfactant, and an amine oxide-based surfactant. Examples of the amino acid surfactant include acylglutamic acid and the like. Examples of the betaine-based surfactant include betaine lauryldimethylaminoacetate and betaine stearyldimethylaminoacetate. Examples of the amine oxide-based surfactant include lauryl dimethylamine oxide.
これらの界面活性剤は、後述する湿潤ゲル生成工程において、反応系中の溶媒と、成長していくシロキサン重合体との間の化学的親和性の差異を小さくし、相分離を抑制する作用をすると考えられている。
These surfactants have the effect of reducing the difference in chemical affinity between the solvent in the reaction system and the growing siloxane polymer in the wet gel formation step described below, and suppressing phase separation. It is believed that.
界面活性剤の添加量は、界面活性剤の種類、あるいはケイ素化合物の種類及び量にも左右されるが、例えばポリシロキサン化合物群及びシランモノマー群の総量100質量部に対し、1~100質量部とすることができる。なお、同添加量は5~60質量部であってもよい。
The amount of the surfactant added depends on the type of the surfactant or the type and amount of the silicon compound. For example, 1 to 100 parts by mass relative to 100 parts by mass of the total of the polysiloxane compound group and the silane monomer group. It can be. Incidentally, the addition amount may be 5 to 60 parts by mass.
熱加水分解性化合物は、熱加水分解により塩基触媒を発生して、反応溶液を塩基性とし、後述する湿潤ゲル生成工程でのゾルゲル反応を促進すると考えられている。よって、この熱加水分解性化合物としては、加水分解後に反応溶液を塩基性にできる化合物であれば、特に限定されず、尿素;ホルムアミド、N-メチルホルムアミド、N,N-ジメチルホルムアミド、アセトアミド、N-メチルアセトアミド、N,N-ジメチルアセトアミド等の酸アミド;ヘキサメチレンテトラミン等の環状窒素化合物などを挙げることができる。これらの中でも、特に尿素は上記促進効果を得られ易い。
(4) It is considered that the thermally hydrolyzable compound generates a basic catalyst by thermal hydrolysis, makes the reaction solution basic, and promotes the sol-gel reaction in the wet gel formation step described later. Accordingly, the thermohydrolyzable compound is not particularly limited as long as it can make the reaction solution basic after hydrolysis, and urea; formamide, N-methylformamide, N, N-dimethylformamide, acetamide, N Acid amides such as -methylacetamide and N, N-dimethylacetamide; and cyclic nitrogen compounds such as hexamethylenetetramine. Among these, urea is particularly easy to obtain the above-mentioned promoting effect.
熱加水分解性化合物の添加量は、後述する湿潤ゲル生成工程でのゾルゲル反応を十分に促進することができる量であれば、特に限定されない。例えば、熱加水分解性化合物として尿素を用いた場合、その添加量は、ポリシロキサン化合物群及びシランモノマー群の総量100質量部に対して、1~200質量部とすることができる。なお、同添加量は2~150質量部であってもよい。添加量を1質量部以上とすることにより、良好な反応性をさらに得易くなり、また、200質量部以下とすることにより、結晶の析出及びゲル密度の低下をさらに抑制し易くなる。
添加 The amount of the thermally hydrolyzable compound to be added is not particularly limited as long as it can sufficiently promote the sol-gel reaction in the wet gel forming step described below. For example, when urea is used as the thermally hydrolyzable compound, the amount of addition can be 1 to 200 parts by mass based on 100 parts by mass of the total of the polysiloxane compound group and the silane monomer group. The amount may be 2 to 150 parts by mass. By setting the addition amount to 1 part by mass or more, it becomes easier to obtain good reactivity, and by setting the addition amount to 200 parts by mass or less, it becomes easier to further suppress precipitation of crystals and reduction in gel density.
ゾル生成工程では、熱線輻射抑制等を目的として、溶媒中にカーボングラファイト、アルミニウム化合物、マグネシウム化合物、銀化合物、チタン化合物等の成分を添加してもよい。
In the sol generation step, components such as carbon graphite, an aluminum compound, a magnesium compound, a silver compound, and a titanium compound may be added to a solvent for the purpose of suppressing heat radiation.
ゾル生成工程の加水分解は、混合液中のケイ素化合物、シリカ粒子、酸触媒、界面活性剤等の種類及び量にも左右されるが、例えば20~60℃の温度環境下で10分~24時間行ってもよく、50~60℃の温度環境下で5分~8時間行ってもよい。これにより、ケイ素化合物中の加水分解性官能基が十分に加水分解され、ケイ素化合物の加水分解生成物をより確実に得ることができる。
The hydrolysis in the sol generation step depends on the type and amount of the silicon compound, silica particles, acid catalyst, surfactant and the like in the mixed solution, but for example, in a temperature environment of 20 to 60 ° C. for 10 minutes to 24 hours. The heat treatment may be performed for a period of time, or for 5 minutes to 8 hours in a temperature environment of 50 to 60 ° C. Thereby, the hydrolyzable functional group in the silicon compound is sufficiently hydrolyzed, and a hydrolysis product of the silicon compound can be obtained more reliably.
ただし、溶媒中に熱加水分解性化合物を添加する場合は、ゾル生成工程の温度環境を、熱加水分解性化合物の加水分解を抑制してゾルのゲル化を抑制する温度に調節してもよい。この時の温度は、熱加水分解性化合物の加水分解を抑制できる温度であれば、いずれの温度であってもよい。例えば、熱加水分解性化合物として尿素を用いた場合は、ゾル生成工程の温度環境は0~40℃とすることができるが、10~30℃であってもよい。
However, when the heat-hydrolyzable compound is added to the solvent, the temperature environment of the sol generation step may be adjusted to a temperature at which the hydrolysis of the heat-hydrolyzable compound is suppressed and the gelation of the sol is suppressed. . The temperature at this time may be any temperature as long as it can suppress hydrolysis of the thermally hydrolyzable compound. For example, when urea is used as the thermally hydrolyzable compound, the temperature environment in the sol generation step can be 0 to 40 ° C., but may be 10 to 30 ° C.
(湿潤ゲル生成工程)
湿潤ゲル生成工程は、ゾル生成工程で得られたゾルをゲル化し、その後熟成して湿潤ゲルを得る工程である。本工程では、ゲル化を促進させるため塩基触媒を用いることができる。 (Wet gel formation step)
The wet gel generation step is a step of gelling the sol obtained in the sol generation step and then aging to obtain a wet gel. In this step, a base catalyst can be used to promote gelation.
湿潤ゲル生成工程は、ゾル生成工程で得られたゾルをゲル化し、その後熟成して湿潤ゲルを得る工程である。本工程では、ゲル化を促進させるため塩基触媒を用いることができる。 (Wet gel formation step)
The wet gel generation step is a step of gelling the sol obtained in the sol generation step and then aging to obtain a wet gel. In this step, a base catalyst can be used to promote gelation.
塩基触媒としては、炭酸カルシウム、炭酸カリウム、炭酸ナトリウム、炭酸バリウム、炭酸マグネシウム、炭酸リチウム、炭酸アンモニウム、炭酸銅(II)、炭酸鉄(II)、炭酸銀(I)等の炭酸塩類;炭酸水素カルシウム、炭酸水素カリウム、炭酸水素ナトリウム、炭酸水素アンモニウム等の炭酸水素塩類;水酸化リチウム、水酸化ナトリウム、水酸化カリウム、水酸化セシウム等のアルカリ金属水酸化物;水酸化アンモニウム、フッ化アンモニウム、塩化アンモニウム、臭化アンモニウム等のアンモニウム化合物;メタ燐酸ナトリウム、ピロ燐酸ナトリウム、ポリ燐酸ナトリウム等の塩基性燐酸ナトリウム塩;アリルアミン、ジアリルアミン、トリアリルアミン、イソプロピルアミン、ジイソプロピルアミン、エチルアミン、ジエチルアミン、トリエチルアミン、2-エチルヘキシルアミン、3-エトキシプロピルアミン、ジイソブチルアミン、3-(ジエチルアミノ)プロピルアミン、ジ-2-エチルヘキシルアミン、3-(ジブチルアミノ)プロピルアミン、テトラメチルエチレンジアミン、t-ブチルアミン、sec-ブチルアミン、プロピルアミン、3-(メチルアミノ)プロピルアミン、3-(ジメチルアミノ)プロピルアミン、3-メトキシアミン、ジメチルエタノールアミン、メチルジエタノールアミン、ジエタノールアミン、トリエタノールアミン等の脂肪族アミン類;モルホリン、N-メチルモルホリン、2-メチルモルホリン、ピペラジン及びその誘導体、ピペリジン及びその誘導体、イミダゾール及びその誘導体等の含窒素複素環状化合物類などが挙げられる。これらの中でも、水酸化アンモニウム(アンモニア水)は、揮発性が高く、乾燥後のエアロゲル粒子中に残存し難いため耐水性を損ない難いという点、さらには経済性の点で優れている。上記の塩基触媒は単独で、又は2種類以上を混合して用いてもよい。
Examples of the base catalyst include carbonates such as calcium carbonate, potassium carbonate, sodium carbonate, barium carbonate, magnesium carbonate, lithium carbonate, ammonium carbonate, copper (II) carbonate, iron (II) carbonate and silver (I) carbonate; hydrogen carbonate Hydrogen carbonates such as calcium, potassium hydrogen carbonate, sodium hydrogen carbonate and ammonium hydrogen carbonate; alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, potassium hydroxide and cesium hydroxide; ammonium hydroxide, ammonium fluoride; Ammonium compounds such as ammonium chloride and ammonium bromide; basic sodium phosphates such as sodium metaphosphate, sodium pyrophosphate and sodium polyphosphate; allylamine, diallylamine, triallylamine, isopropylamine, diisopropylamine, ethylamine, diethylamine Ruamine, triethylamine, 2-ethylhexylamine, 3-ethoxypropylamine, diisobutylamine, 3- (diethylamino) propylamine, di-2-ethylhexylamine, 3- (dibutylamino) propylamine, tetramethylethylenediamine, t-butylamine, aliphatic amines such as sec-butylamine, propylamine, 3- (methylamino) propylamine, 3- (dimethylamino) propylamine, 3-methoxyamine, dimethylethanolamine, methyldiethanolamine, diethanolamine and triethanolamine; morpholine Heterocyclic compounds such as N-methylmorpholine, 2-methylmorpholine, piperazine and its derivatives, piperidine and its derivatives, imidazole and its derivatives, etc. And the like. Among them, ammonium hydroxide (aqueous ammonia) is excellent in that it has high volatility and hardly remains in the airgel particles after drying, so that it does not easily impair water resistance, and furthermore, it is economical. The above base catalysts may be used alone or in combination of two or more.
塩基触媒を用いることで、ゾル中のケイ素化合物、及びシリカ粒子の、脱水縮合反応又は脱アルコール縮合反応を促進することができ、ゾルのゲル化をより短時間で行うことができる。また、これにより、強度(剛性)のより高い湿潤ゲルを得ることができる。特に、アンモニアは揮発性が高く、エアロゲル粒子中に残留し難いので、塩基触媒としてアンモニアを用いることで、より耐水性の優れたエアロゲル粒子を得ることができる。
By using a base catalyst, a dehydration condensation reaction or a dealcoholization condensation reaction of the silicon compound and silica particles in the sol can be promoted, and the sol can be gelled in a shorter time. In addition, thereby, a wet gel having higher strength (rigidity) can be obtained. In particular, ammonia has high volatility and hardly remains in the airgel particles. Therefore, by using ammonia as the base catalyst, airgel particles having more excellent water resistance can be obtained.
塩基触媒の添加量は、ポリシロキサン化合物群及びシランモノマー群の総量100質量部に対し、0.5~5質量部とすることができるが、1~4質量部であってもよい。0.5質量部以上とすることにより、ゲル化をより短時間で行うことができ、5質量部以下とすることにより、耐水性の低下をより抑制することができる。
The amount of the base catalyst added can be 0.5 to 5 parts by mass, or 1 to 4 parts by mass, based on 100 parts by mass of the total of the polysiloxane compound group and the silane monomer group. When the amount is 0.5 parts by mass or more, gelation can be performed in a shorter time, and when the amount is 5 parts by mass or less, a decrease in water resistance can be further suppressed.
湿潤ゲル生成工程におけるゾルのゲル化は、溶媒及び塩基触媒が揮発しないように密閉容器内で行ってもよい。ゲル化温度は、30~90℃とすることができるが、40~80℃であってもよい。ゲル化温度を30℃以上とすることにより、ゲル化をより短時間に行うことができ、強度(剛性)のより高い湿潤ゲルを得ることができる。また、ゲル化温度を90℃以下にすることにより、溶媒(特にアルコール)の揮発を抑制し易くなるため、体積収縮を抑えながらゲル化することができる。
ゲ ル The gelation of the sol in the wet gel formation step may be performed in a closed container so that the solvent and the base catalyst do not volatilize. The gelling temperature can be between 30 and 90 ° C, but may be between 40 and 80 ° C. By setting the gelation temperature to 30 ° C. or higher, gelation can be performed in a shorter time, and a wet gel having higher strength (rigidity) can be obtained. Further, by setting the gelling temperature to 90 ° C. or lower, the volatilization of the solvent (particularly, alcohol) is easily suppressed, so that gelation can be performed while suppressing volume shrinkage.
湿潤ゲル生成工程における熟成は、溶媒及び塩基触媒が揮発しないように密閉容器内で行ってもよい。熟成により、湿潤ゲルを構成する成分の結合が強くなり、その結果、乾燥時の収縮を抑制するのに十分な強度(剛性)の高い湿潤ゲルを得ることができる。熟成温度は、30~90℃とすることができるが、40~80℃であってもよい。熟成温度を30℃以上とすることにより、強度(剛性)のより高い湿潤ゲルを得ることができ、熟成温度を90℃以下にすることにより、溶媒(特にアルコール)の揮発を抑制し易くなるため、体積収縮を抑えながらゲル化することができる。
The aging in the wet gel forming step may be performed in a closed container so that the solvent and the base catalyst do not volatilize. The aging strengthens the binding of the components constituting the wet gel, and as a result, a wet gel having high strength (rigidity) enough to suppress shrinkage during drying can be obtained. The aging temperature can be 30 to 90 ° C, but may be 40 to 80 ° C. By setting the aging temperature to 30 ° C. or higher, a wet gel having higher strength (rigidity) can be obtained, and by setting the aging temperature to 90 ° C. or lower, the volatilization of the solvent (particularly alcohol) is easily suppressed. Gelation can be performed while suppressing volume shrinkage.
なお、ゾルのゲル化終了時点を判別することは困難な場合が多いため、ゾルのゲル化とその後の熟成とは、連続して一連の操作で行ってもよい。
た め Since it is often difficult to determine the end point of the gelation of the sol, the gelation of the sol and the subsequent aging may be performed continuously in a series of operations.
ゲル化時間と熟成時間は、ゲル化温度及び熟成温度により適宜設定することができる。ゾル中にシリカ粒子が含まれている場合は、含まれていない場合と比較して、特にゲル化時間を短縮することができる。この理由は、ゾル中のケイ素化合物が有するシラノール基又は反応性基が、シリカ粒子のシラノール基と水素結合又は化学結合を形成するためであると推察する。なお、ゲル化時間は10~120分間とすることができるが、20~90分間であってもよい。ゲル化時間を10分間以上とすることにより均質な湿潤ゲルを得易くなり、120分間以下とすることにより後述する洗浄及び溶媒置換工程から乾燥工程の簡略化が可能となる。なお、ゲル化及び熟成の工程全体として、ゲル化時間と熟成時間との合計時間は、4~480時間とすることができるが、6~120時間であってもよい。ゲル化時間と熟成時間の合計を4時間以上とすることにより、強度(剛性)のより高い湿潤ゲルを得ることができ、480時間以下にすることにより熟成の効果をより維持し易くなる。
The gelation time and the aging time can be appropriately set according to the gelation temperature and the aging temperature. When silica particles are contained in the sol, the gelation time can be particularly shortened as compared with the case where silica particles are not contained. This is presumed to be because the silanol group or the reactive group of the silicon compound in the sol forms a hydrogen bond or a chemical bond with the silanol group of the silica particles. The gelation time can be 10 to 120 minutes, but may be 20 to 90 minutes. By setting the gelling time to 10 minutes or more, it becomes easy to obtain a uniform wet gel, and by setting the gelling time to 120 minutes or less, the washing and solvent replacement steps to be described later can be simplified from the drying step. The total time of the gelation time and the aging time in the entire gelation and aging step can be 4 to 480 hours, but may be 6 to 120 hours. By setting the total of the gelation time and the aging time to 4 hours or more, a wet gel having higher strength (rigidity) can be obtained, and by setting the total time to 480 hours or less, the effect of the aging can be more easily maintained.
得られるエアロゲル粒子の密度を下げたり、平均細孔径を大きくするために、ゲル化温度及び熟成温度を上記範囲内で高めたり、ゲル化時間と熟成時間の合計時間を上記範囲内で長くしてもよい。また、得られるエアロゲル粒子の密度を上げたり、平均細孔径を小さくするために、ゲル化温度及び熟成温度を上記範囲内で低くしたり、ゲル化時間と熟成時間の合計時間を上記範囲内で短くしてもよい。
To lower the density of the obtained airgel particles, or to increase the average pore size, increase the gelation temperature and aging temperature within the above range, or increase the total time of the gelation time and the aging time within the above range. Is also good. Also, to increase the density of the obtained airgel particles, to reduce the average pore diameter, to lower the gelation temperature and aging temperature in the above range, or to set the total time of gelation time and aging time in the above range. It may be shorter.
(湿潤ゲル粉砕工程)
湿潤ゲル粉砕工程を行う場合、湿潤ゲル生成工程で得られた湿潤ゲルを粉砕する。粉砕は、例えば、ヘンシャル型ミキサーに湿潤ゲルを入れるか、又はミキサー内で湿潤ゲル生成工程を行い、ミキサーを適度な条件(回転数及び時間)で運転することにより行うことができる。また、より簡易的には密閉可能な容器に湿潤ゲルを入れるか、又は密閉可能な容器内で湿潤ゲル生成工程を行い、シェイカー等の振盪装置を用いて、適度な時間振盪することにより行うことができる。なお、必要に応じて、ジェットミル、ローラーミル、ビーズミル等を用いて、湿潤ゲルの粒子径を調整することもできる。 (Wet gel crushing process)
When performing the wet gel pulverizing step, the wet gel obtained in the wet gel generating step is pulverized. The pulverization can be performed, for example, by putting the wet gel in a Henshall type mixer, or by performing a wet gel generation step in the mixer, and operating the mixer under appropriate conditions (number of rotations and time). In addition, more simply, a wet gel is placed in a sealable container, or a wet gel generation step is performed in a sealable container, and shaking is performed by using a shaking device or the like for an appropriate time. Can be. Note that the particle size of the wet gel can be adjusted using a jet mill, a roller mill, a bead mill, or the like, if necessary.
湿潤ゲル粉砕工程を行う場合、湿潤ゲル生成工程で得られた湿潤ゲルを粉砕する。粉砕は、例えば、ヘンシャル型ミキサーに湿潤ゲルを入れるか、又はミキサー内で湿潤ゲル生成工程を行い、ミキサーを適度な条件(回転数及び時間)で運転することにより行うことができる。また、より簡易的には密閉可能な容器に湿潤ゲルを入れるか、又は密閉可能な容器内で湿潤ゲル生成工程を行い、シェイカー等の振盪装置を用いて、適度な時間振盪することにより行うことができる。なお、必要に応じて、ジェットミル、ローラーミル、ビーズミル等を用いて、湿潤ゲルの粒子径を調整することもできる。 (Wet gel crushing process)
When performing the wet gel pulverizing step, the wet gel obtained in the wet gel generating step is pulverized. The pulverization can be performed, for example, by putting the wet gel in a Henshall type mixer, or by performing a wet gel generation step in the mixer, and operating the mixer under appropriate conditions (number of rotations and time). In addition, more simply, a wet gel is placed in a sealable container, or a wet gel generation step is performed in a sealable container, and shaking is performed by using a shaking device or the like for an appropriate time. Can be. Note that the particle size of the wet gel can be adjusted using a jet mill, a roller mill, a bead mill, or the like, if necessary.
(洗浄及び溶媒置換工程)
洗浄及び溶媒置換工程は、湿潤ゲル生成工程又は湿潤ゲル粉砕工程により得られた湿潤ゲルを洗浄する工程(洗浄工程)と、湿潤ゲル中の洗浄液を乾燥条件(後述の乾燥工程)に適した溶媒に置換する工程(溶媒置換工程)を有する工程である。洗浄及び溶媒置換工程は、湿潤ゲルを洗浄する工程を行わず、溶媒置換工程のみを行う形態でも実施可能であるが、湿潤ゲル中の未反応物、副生成物等の不純物を低減し、より純度の高いエアロゲル粒子の製造を可能にする観点からは、湿潤ゲルを洗浄してもよい。 (Washing and solvent replacement process)
The washing and solvent replacement step includes a step of washing the wet gel obtained in the wet gel generation step or the wet gel pulverizing step (washing step) and a step of washing the washing liquid in the wet gel with a solvent suitable for drying conditions (a drying step described later). (A solvent replacement step). The washing and solvent replacement step can be performed in a form in which only the solvent replacement step is performed without performing the step of washing the wet gel, but it is possible to reduce impurities such as unreacted substances and by-products in the wet gel. The wet gel may be washed from the viewpoint of enabling the production of highly pure airgel particles.
洗浄及び溶媒置換工程は、湿潤ゲル生成工程又は湿潤ゲル粉砕工程により得られた湿潤ゲルを洗浄する工程(洗浄工程)と、湿潤ゲル中の洗浄液を乾燥条件(後述の乾燥工程)に適した溶媒に置換する工程(溶媒置換工程)を有する工程である。洗浄及び溶媒置換工程は、湿潤ゲルを洗浄する工程を行わず、溶媒置換工程のみを行う形態でも実施可能であるが、湿潤ゲル中の未反応物、副生成物等の不純物を低減し、より純度の高いエアロゲル粒子の製造を可能にする観点からは、湿潤ゲルを洗浄してもよい。 (Washing and solvent replacement process)
The washing and solvent replacement step includes a step of washing the wet gel obtained in the wet gel generation step or the wet gel pulverizing step (washing step) and a step of washing the washing liquid in the wet gel with a solvent suitable for drying conditions (a drying step described later). (A solvent replacement step). The washing and solvent replacement step can be performed in a form in which only the solvent replacement step is performed without performing the step of washing the wet gel, but it is possible to reduce impurities such as unreacted substances and by-products in the wet gel. The wet gel may be washed from the viewpoint of enabling the production of highly pure airgel particles.
洗浄工程では、湿潤ゲル生成工程又は湿潤ゲル粉砕工程により得られた湿潤ゲルを洗浄する。当該洗浄は、例えば水又は有機溶媒を用いて繰り返し行うことができる。この際、加温することにより洗浄効率を向上させることができる。
In the washing step, the wet gel obtained in the wet gel forming step or the wet gel pulverizing step is washed. The washing can be repeatedly performed using, for example, water or an organic solvent. At this time, the cleaning efficiency can be improved by heating.
有機溶媒としては、メタノール、エタノール、1-プロパノール、2-プロパノール、1-ブタノール、アセトン、メチルエチルケトン、1,2-ジメトキシエタン、アセトニトリル、ヘキサン、トルエン、ジエチルエーテル、クロロホルム、酢酸エチル、テトラヒドロフラン、塩化メチレン、N、N-ジメチルホルムアミド、ジメチルスルホキシド、酢酸、ギ酸等の各種の有機溶媒を使用することができる。上記の有機溶媒は単独で、又は2種類以上を混合して用いてもよい。
Examples of the organic solvent include methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, acetone, methyl ethyl ketone, 1,2-dimethoxyethane, acetonitrile, hexane, toluene, diethyl ether, chloroform, ethyl acetate, tetrahydrofuran, and methylene chloride. , N, N-dimethylformamide, dimethylsulfoxide, acetic acid, formic acid and the like can be used. The above organic solvents may be used alone or in combination of two or more.
後述する溶媒置換工程では、乾燥によるゲルの収縮を抑制するため、低表面張力の溶媒を用いることができる。しかし、低表面張力の溶媒は、一般的に水との相互溶解度が極めて低い。そのため、溶媒置換工程において低表面張力の溶媒を用いる場合、洗浄工程で用いる有機溶媒としては、水及び低表面張力の溶媒の双方に対して高い相互溶解性を有する親水性有機溶媒が挙げられる。なお、洗浄工程において用いられる親水性有機溶媒は、溶媒置換工程のための予備置換の役割を果たすことができる。上記の有機溶媒の中で、親水性有機溶媒としては、メタノール、エタノール、2-プロパノール、アセトン、メチルエチルケトン等が挙げられる。なお、メタノール、エタノール、メチルエチルケトン等は経済性の点で優れている。
で は In the solvent replacement step described below, a solvent having a low surface tension can be used to suppress shrinkage of the gel due to drying. However, low surface tension solvents generally have very low mutual solubility with water. Therefore, when a low surface tension solvent is used in the solvent replacement step, the organic solvent used in the washing step includes a hydrophilic organic solvent having high mutual solubility in both water and the low surface tension solvent. Note that the hydrophilic organic solvent used in the washing step can serve as a preliminary replacement for the solvent replacement step. Among the above organic solvents, examples of the hydrophilic organic solvent include methanol, ethanol, 2-propanol, acetone, and methyl ethyl ketone. In addition, methanol, ethanol, methyl ethyl ketone, etc. are excellent in terms of economy.
洗浄工程に使用される水又は有機溶媒の量としては、湿潤ゲル中の溶媒を十分に置換し、洗浄できる量とすることができる。当該量は、湿潤ゲルの容量に対して3~10倍の量とすることができる。洗浄は、洗浄後の湿潤ゲル中の含水率が、シリカ質量に対し、10質量%以下となるまで繰り返すことができる。
(4) The amount of water or the organic solvent used in the washing step can be set to an amount that can sufficiently replace the solvent in the wet gel and can be washed. The amount can be 3 to 10 times the volume of the wet gel. Washing can be repeated until the water content in the wet gel after washing becomes 10% by mass or less based on the mass of silica.
洗浄工程における温度環境は、洗浄に用いる溶媒の沸点以下の温度とすることができ、例えば、メタノールを用いる場合は、30~60℃程度の加温とすることができる。
温度 The temperature environment in the washing step can be a temperature equal to or lower than the boiling point of the solvent used for washing. For example, when methanol is used, the temperature can be raised to about 30 to 60 ° C.
溶媒置換工程では、乾燥工程におけるエアロゲルの収縮を抑制するため、洗浄した湿潤ゲルの溶媒を所定の置換用溶媒に置き換える。この際、加温することにより置換効率を向上させることができる。置換用溶媒としては、具体的には、乾燥工程において、乾燥に用いられる溶媒の臨界点未満の温度にて、大気圧下で乾燥する場合は、後述の低表面張力の溶媒が挙げられる。一方、超臨界乾燥をする場合は、置換用溶媒としては、例えば、エタノール、メタノール、2-プロパノール、ジクロロジフルオロメタン、二酸化炭素等、又はこれらを2種以上混合した溶媒が挙げられる。
In the solvent replacement step, the solvent of the washed wet gel is replaced with a predetermined replacement solvent in order to suppress shrinkage of the airgel in the drying step. At this time, the replacement efficiency can be improved by heating. As the substitution solvent, specifically, in the drying step, when drying at a temperature lower than the critical point of the solvent used for drying under atmospheric pressure, a solvent having a low surface tension, which will be described later, may be mentioned. On the other hand, in the case of supercritical drying, examples of the replacement solvent include ethanol, methanol, 2-propanol, dichlorodifluoromethane, carbon dioxide, and the like, or a solvent obtained by mixing two or more of these.
低表面張力の溶媒としては、20℃における表面張力が30mN/m以下の溶媒が挙げられる。なお、当該表面張力は25mN/m以下であっても、又は20mN/m以下であってもよい。低表面張力の溶媒としては、例えば、ペンタン(15.5)、ヘキサン(18.4)、ヘプタン(20.2)、オクタン(21.7)、2-メチルペンタン(17.4)、3-メチルペンタン(18.1)、2-メチルヘキサン(19.3)、シクロペンタン(22.6)、シクロヘキサン(25.2)、1-ペンテン(16.0)等の脂肪族炭化水素類;ベンゼン(28.9)、トルエン(28.5)、m-キシレン(28.7)、p-キシレン(28.3)等の芳香族炭化水素類;ジクロロメタン(27.9)、クロロホルム(27.2)、四塩化炭素(26.9)、1-クロロプロパン(21.8)、2-クロロプロパン(18.1)等のハロゲン化炭化水素類;エチルエーテル(17.1)、プロピルエーテル(20.5)、イソプロピルエーテル(17.7)、ブチルエチルエーテル(20.8)、1,2-ジメトキシエタン(24.6)等のエーテル類;アセトン(23.3)、メチルエチルケトン(24.6)、メチルプロピルケトン(25.1)、ジエチルケトン(25.3)等のケトン類;酢酸メチル(24.8)、酢酸エチル(23.8)、酢酸プロピル(24.3)、酢酸イソプロピル(21.2)、酢酸イソブチル(23.7)、エチルブチレート(24.6)等のエステル類などが挙げられる(かっこ内は20℃での表面張力を示し、単位は[mN/m]である)。これらの中で、脂肪族炭化水素類(ヘキサン、ヘプタン等)は低表面張力でありかつ作業環境性に優れている。また、これらの中でも、アセトン、メチルエチルケトン、1,2-ジメトキシエタン等の親水性有機溶媒を用いることで、上記洗浄工程の有機溶媒と兼用することができる。なお、これらの中でも、さらに後述する乾燥工程における乾燥が容易な点で、常圧での沸点が100℃以下の溶媒を用いてもよい。上記の溶媒は単独で、又は2種類以上を混合して用いてもよい。
溶媒 Examples of the solvent having a low surface tension include a solvent having a surface tension at 30C of 30 mN / m or less. The surface tension may be 25 mN / m or less, or 20 mN / m or less. Examples of low surface tension solvents include pentane (15.5), hexane (18.4), heptane (20.2), octane (21.7), 2-methylpentane (17.4), Aliphatic hydrocarbons such as methylpentane (18.1), 2-methylhexane (19.3), cyclopentane (22.6), cyclohexane (25.2) and 1-pentene (16.0); benzene Aromatic hydrocarbons such as (28.9), toluene (28.5), m-xylene (28.7) and p-xylene (28.3); dichloromethane (27.9), chloroform (27.2) ), Carbon tetrachloride (26.9), 1-chloropropane (21.8), 2-chloropropane (18.1) and other halogenated hydrocarbons; ethyl ether (17.1), propyl ether (20.5) ), Isop Ethers such as pill ether (17.7), butyl ethyl ether (20.8) and 1,2-dimethoxyethane (24.6); acetone (23.3), methyl ethyl ketone (24.6), methyl propyl ketone (25.1), ketones such as diethyl ketone (25.3); methyl acetate (24.8), ethyl acetate (23.8), propyl acetate (24.3), isopropyl acetate (21.2), Esters such as isobutyl acetate (23.7) and ethyl butyrate (24.6) are exemplified (the values in parentheses indicate the surface tension at 20 ° C., and the unit is [mN / m]). Among them, aliphatic hydrocarbons (hexane, heptane, etc.) have low surface tension and excellent work environment. Among these, by using a hydrophilic organic solvent such as acetone, methyl ethyl ketone, and 1,2-dimethoxyethane, the organic solvent can also be used as the organic solvent in the washing step. Among these, a solvent having a boiling point at normal pressure of 100 ° C. or lower may be used because drying in a drying step described later is easy. The above solvents may be used alone or in combination of two or more.
溶媒置換工程に使用される溶媒の量としては、洗浄後の湿潤ゲル中の溶媒を十分に置換できる量とすることができる。当該量は、湿潤ゲルの容量に対して3~10倍の量とすることができる。
溶媒 The amount of the solvent used in the solvent replacement step can be set to an amount that can sufficiently replace the solvent in the wet gel after washing. The amount can be 3 to 10 times the volume of the wet gel.
溶媒置換工程における温度環境は、置換に用いる溶媒の沸点以下の温度とすることができ、例えば、ヘプタンを用いる場合は、30~60℃程度の加温とすることができる。
温度 The temperature environment in the solvent replacement step can be a temperature equal to or lower than the boiling point of the solvent used for replacement. For example, when heptane is used, the temperature can be raised to about 30 to 60 ° C.
なお、ゲル中にシリカ粒子が含まれている場合、溶媒置換工程は必須ではない。推察されるメカニズムとしては次のとおりである。すなわち、シリカ粒子が三次元網目状の骨格の支持体として機能することにより、当該骨格が支持され、乾燥工程におけるゲルの収縮が抑制される。そのため、洗浄に用いた溶媒を置換せずに、ゲルをそのまま乾燥工程に付すことができると考えられる。このように、シリカ粒子を用いることで、洗浄及び溶媒置換工程から乾燥工程の簡略化が可能である。
場合 When silica particles are contained in the gel, the solvent replacement step is not essential. The inferred mechanism is as follows. That is, since the silica particles function as a support for the three-dimensional network skeleton, the skeleton is supported, and shrinkage of the gel in the drying step is suppressed. Therefore, it is considered that the gel can be directly subjected to the drying step without replacing the solvent used for washing. As described above, the use of the silica particles makes it possible to simplify the washing and solvent replacement steps to the drying step.
(乾燥工程)
乾燥工程では、上記のとおり洗浄及び(必要に応じ)溶媒置換した湿潤ゲルを乾燥させる。これにより、エアロゲル(エアロゲルブロック又はエアロゲル粒子)を得ることができる。すなわち、上記ゾルから生成された湿潤ゲルを乾燥してなるエアロゲルを得ることができる。 (Drying process)
In the drying step, the wet gel that has been washed and (if necessary) replaced with a solvent is dried as described above. Thereby, an airgel (an airgel block or an airgel particle) can be obtained. That is, an aerogel obtained by drying the wet gel generated from the sol can be obtained.
乾燥工程では、上記のとおり洗浄及び(必要に応じ)溶媒置換した湿潤ゲルを乾燥させる。これにより、エアロゲル(エアロゲルブロック又はエアロゲル粒子)を得ることができる。すなわち、上記ゾルから生成された湿潤ゲルを乾燥してなるエアロゲルを得ることができる。 (Drying process)
In the drying step, the wet gel that has been washed and (if necessary) replaced with a solvent is dried as described above. Thereby, an airgel (an airgel block or an airgel particle) can be obtained. That is, an aerogel obtained by drying the wet gel generated from the sol can be obtained.
乾燥の手法としては特に制限されず、公知の常圧乾燥、超臨界乾燥又は凍結乾燥を用いることができる。これらの中で、低密度のエアロゲルを製造し易いという観点からは、常圧乾燥又は超臨界乾燥を用いることができる。また、低コストで生産可能という観点からは、常圧乾燥を用いることができる。なお、本実施形態において、常圧とは0.1MPa(大気圧)を意味する。
The method of drying is not particularly limited, and known atmospheric drying, supercritical drying or freeze drying can be used. Among these, normal pressure drying or supercritical drying can be used from the viewpoint of easily producing a low-density airgel. From the viewpoint of production at low cost, normal pressure drying can be used. In the present embodiment, the normal pressure means 0.1 MPa (atmospheric pressure).
エアロゲルは、洗浄及び(必要に応じ)溶媒置換した湿潤ゲルを、乾燥に用いられる溶媒の臨界点未満の温度にて、大気圧下で乾燥することにより得ることができる。乾燥温度は、置換された溶媒(溶媒置換を行わない場合は洗浄に用いられた溶媒)の種類により異なるが、特に高温での乾燥が溶媒の蒸発速度を速め、ゲルに大きな亀裂を生じさせる場合があるという点に鑑み、20~150℃とすることができる。なお、当該乾燥温度は60~120℃であってもよい。また、乾燥時間は、湿潤ゲルの容量及び乾燥温度により異なるが、4~120時間とすることができる。なお、生産性を阻害しない範囲内において臨界点未満の圧力をかけて乾燥を早めることも、常圧乾燥に包含されるものとする。
The aerogel can be obtained by drying the wet gel after washing and (if necessary) solvent replacement at a temperature below the critical point of the solvent used for drying under atmospheric pressure. The drying temperature varies depending on the type of solvent that has been replaced (the solvent used for washing if solvent replacement is not performed), especially when drying at high temperatures increases the evaporation rate of the solvent and causes large cracks in the gel. In view of the above, the temperature can be set to 20 to 150 ° C. Incidentally, the drying temperature may be 60 to 120 ° C. The drying time varies depending on the volume of the wet gel and the drying temperature, but can be 4 to 120 hours. It should be noted that the drying under a normal pressure includes applying a pressure lower than the critical point within a range not impairing the productivity to accelerate the drying.
エアロゲルは、また、洗浄及び(必要に応じ)溶媒置換した湿潤ゲルを、超臨界乾燥することによっても得ることができる。超臨界乾燥は、公知の手法にて行うことができる。超臨界乾燥する方法としては、例えば、湿潤ゲルに含まれる溶媒の臨界点以上の温度及び圧力にて溶媒を除去する方法が挙げられる。あるいは、超臨界乾燥する方法としては、湿潤ゲルを、液化二酸化炭素中に、例えば、20~25℃、5~20MPa程度の条件で浸漬することで、湿潤ゲルに含まれる溶媒の全部又は一部を当該溶媒より臨界点の低い二酸化炭素に置換した後、二酸化炭素を単独で、又は二酸化炭素及び溶媒の混合物を除去する方法が挙げられる。
Airgel can also be obtained by supercritical drying of a wet gel that has been washed and (if necessary) replaced with a solvent. Supercritical drying can be performed by a known method. As a method of supercritical drying, for example, a method of removing the solvent at a temperature and a pressure higher than the critical point of the solvent contained in the wet gel may be mentioned. Alternatively, as a method of supercritical drying, the wet gel is immersed in liquefied carbon dioxide, for example, at a temperature of about 20 to 25 ° C. and about 5 to 20 MPa, so that all or a part of the solvent contained in the wet gel is dried. Is replaced with carbon dioxide having a lower critical point than the solvent, and then carbon dioxide alone or a mixture of carbon dioxide and a solvent is removed.
このような常圧乾燥又は超臨界乾燥により得られたエアロゲルは、さらに常圧下にて、105~200℃で0.5~2時間程度追加乾燥してもよい。これにより、密度が低く、小さな細孔を有するエアロゲルをさらに得易くなる。追加乾燥は、常圧下にて、150~200℃で行ってもよい。
エ ア The airgel obtained by such normal pressure drying or supercritical drying may be additionally dried at 105 to 200 ° C. under normal pressure for about 0.5 to 2 hours. This makes it easier to obtain an airgel having a low density and small pores. The additional drying may be performed at 150 to 200 ° C. under normal pressure.
(粉砕工程)
湿潤ゲル粉砕工程を行わない場合は、乾燥により得られたエアロゲル(エアロゲルブロック)を粉砕することによりエアロゲル粒子を得る。例えば、ジェットミル、ローラーミル、ビーズミル、ハンマーミル等にエアロゲルを入れ、適度な回転数と時間で運転することにより行うことができる。 (Crushing process)
When the wet gel pulverizing step is not performed, the airgel (aerogel block) obtained by drying is pulverized to obtain airgel particles. For example, it can be carried out by putting aerogel into a jet mill, roller mill, bead mill, hammer mill or the like and operating at an appropriate rotation speed and time.
湿潤ゲル粉砕工程を行わない場合は、乾燥により得られたエアロゲル(エアロゲルブロック)を粉砕することによりエアロゲル粒子を得る。例えば、ジェットミル、ローラーミル、ビーズミル、ハンマーミル等にエアロゲルを入れ、適度な回転数と時間で運転することにより行うことができる。 (Crushing process)
When the wet gel pulverizing step is not performed, the airgel (aerogel block) obtained by drying is pulverized to obtain airgel particles. For example, it can be carried out by putting aerogel into a jet mill, roller mill, bead mill, hammer mill or the like and operating at an appropriate rotation speed and time.
<塗液及び塗液の調製方法>
塗液は、上述のエアロゲル粒子、バインダ樹脂及び液状媒体を含む。 <Coating liquid and method for preparing coating liquid>
The coating liquid contains the airgel particles, the binder resin, and the liquid medium described above.
塗液は、上述のエアロゲル粒子、バインダ樹脂及び液状媒体を含む。 <Coating liquid and method for preparing coating liquid>
The coating liquid contains the airgel particles, the binder resin, and the liquid medium described above.
バインダ樹脂は、塗膜形成後にエアロゲル粒子同士を結着する機能を有する。バインダ樹脂としては、例えば、エポキシ樹脂、シリコーン樹脂、フェノール樹脂、尿素樹脂、メラミン樹脂、ポリウレタン樹脂、ポリエチレン樹脂、ポリプロピレン樹脂、ポリスチレン樹脂、ポリエステル樹脂、アクリル樹脂、ポリ塩化ビニル樹脂、ポリ酢酸ビニル樹脂、ポリアミド樹脂、ポリイミド樹脂、セルロース系樹脂、ポリビニル系樹脂等が挙げられる。これらの中でも、耐熱性及び強靭性という観点から、シリコーン樹脂、アクリル樹脂、フェノール樹脂及びポリエステル樹脂を好適に用いることができる。
The binder resin has a function of binding the airgel particles after forming the coating film. As the binder resin, for example, epoxy resin, silicone resin, phenol resin, urea resin, melamine resin, polyurethane resin, polyethylene resin, polypropylene resin, polystyrene resin, polyester resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, Examples thereof include a polyamide resin, a polyimide resin, a cellulose resin, and a polyvinyl resin. Among them, from the viewpoint of heat resistance and toughness, silicone resin, acrylic resin, phenol resin and polyester resin can be preferably used.
なお、セルロース系樹脂としては、例えば、ヒドロキシプロピルメチルセルロース、カルボキシメチルセルロースアンモニウム、ヒドロキシエチルメチルセルロース等が挙げられる。また、ポリビニル系樹脂としては、例えば、ポリビニルアルコール、ポリビニルピロリドン等が挙げられる。
セ ル ロ ー ス As the cellulose resin, for example, hydroxypropylmethylcellulose, carboxymethylcellulose ammonium, hydroxyethylmethylcellulose and the like can be mentioned. Examples of the polyvinyl resin include polyvinyl alcohol and polyvinyl pyrrolidone.
バインダ樹脂が熱硬化性樹脂であるとき、塗液は、硬化剤をさらに含有していてよい。硬化剤は特に限定されず、熱硬化性樹脂の種類に応じて適宜変更してよい。例えば、熱硬化性樹脂がエポキシ樹脂であるとき、硬化剤としては、公知のエポキシ樹脂硬化剤を用いることができる。エポキシ樹脂硬化剤としては、例えば、アミン系硬化剤、酸無水物系硬化剤、ポリアミド系硬化剤等が例示でき、反応性の観点からはアミン系硬化剤及びポリアミド系硬化剤を好適に用いることができる。
と き When the binder resin is a thermosetting resin, the coating liquid may further contain a curing agent. The curing agent is not particularly limited, and may be appropriately changed according to the type of the thermosetting resin. For example, when the thermosetting resin is an epoxy resin, a known epoxy resin curing agent can be used as the curing agent. Examples of the epoxy resin curing agent include, for example, an amine curing agent, an acid anhydride curing agent, a polyamide curing agent, and the like. From the viewpoint of reactivity, preferably use an amine curing agent and a polyamide curing agent. Can be.
液状媒体としては水及び有機溶媒が挙げられる。有機溶媒としては、エアロゲル粒子を分散し得るものであれば特に制限はなく、例えば、トルエン、キシレン、メシチレン、クメン、p-シメン等の芳香族炭化水素類;ヘキサン、ヘプタン、ペンタン等の脂肪族炭化水素類;ジエチルエーテル、テトラヒドロフラン、1,4-ジオキサン等のエーテル類;メタノール、エタノール、イソプロパノール(イソプロピルアルコール)、ブタノール、エチレングリコール、プロピレングリコール等のアルコール類;アセトン、メチルエチルケトン、メチルイソブチルケトン、シクロヘキサノン、4-ヒドロキシ-4-メチル-2-ペンタノン等のケトン類;酢酸メチル、酢酸エチル、酢酸ブチル等のエステル類;N,N-ジメチルホルムアミド、N,N-ジメチルアセトアミド、N-メチルピロリドン等のアミド類などが挙げられる。これらの中でも、揮発性、沸点等の観点から、アルコール類及びケトン類を用いることができ、特にアルコール類を好適に用いることができる。アルコール類及びケトン類は、水、水系樹脂等との混合が容易であるため、それらの成分との併用時にも好適である。
Liquid media include water and organic solvents. The organic solvent is not particularly limited as long as it can disperse the airgel particles. Examples thereof include aromatic hydrocarbons such as toluene, xylene, mesitylene, cumene and p-cymene; and aliphatic hydrocarbons such as hexane, heptane and pentane. Hydrocarbons; ethers such as diethyl ether, tetrahydrofuran, and 1,4-dioxane; alcohols such as methanol, ethanol, isopropanol (isopropyl alcohol), butanol, ethylene glycol and propylene glycol; acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone And ketones such as 4-hydroxy-4-methyl-2-pentanone; esters such as methyl acetate, ethyl acetate and butyl acetate; N, N-dimethylformamide, N, N-dimethylacetamide, N-methylpyrrolid An amide such as emissions and the like. Among these, alcohols and ketones can be used from the viewpoints of volatility, boiling point, and the like, and alcohols can be particularly preferably used. Since alcohols and ketones can be easily mixed with water, an aqueous resin or the like, they are also suitable when used in combination with those components.
塗液は、他の成分として増粘剤、繊維状物質、顔料、レベリング剤等を含んでいてもよい。
The coating liquid may contain a thickener, a fibrous substance, a pigment, a leveling agent and the like as other components.
増粘剤は塗液の粘性を向上させ、対象に対する塗工性をより良好にすることができる。増粘剤としては、例えば、フュームドシリカ、粘土鉱物等の微粒子が挙げられる。
(4) The thickener can improve the viscosity of the coating liquid and improve the coating property for the object. Examples of the thickener include fine particles such as fumed silica and clay mineral.
繊維状物質は塗膜形成後にエアロゲル粒子間のアンカー機能を発現することができ、塗膜強度をより向上することができる。繊維状物質としては特に制限されず、有機繊維及び無機繊維が挙げられる。有機繊維としては、例えば、ポリアミド系繊維、ポリイミド系繊維、ポリビニルアルコール系繊維、ポリ塩化ビニリデン系繊維、ポリ塩化ビニル系繊維、ポリエステル系繊維、ポリアクリロニトリル系繊維、ポリエチレン系繊維、ポリプロピレン系繊維、ポリウレタン系繊維、フェノール系繊維、ポリエーテルエステル系繊維、ポリ乳酸系繊維、ポリカーボネート系繊維等が挙げられる。無機繊維としては、例えば、ガラス繊維、炭素繊維、セラミック繊維、金属繊維等が挙げられる。
The fibrous substance can exhibit an anchor function between the airgel particles after the formation of the coating film, and can further improve the coating film strength. The fibrous substance is not particularly limited, and includes organic fibers and inorganic fibers. Examples of the organic fiber include polyamide fiber, polyimide fiber, polyvinyl alcohol fiber, polyvinylidene chloride fiber, polyvinyl chloride fiber, polyester fiber, polyacrylonitrile fiber, polyethylene fiber, polypropylene fiber, and polyurethane fiber. Fiber, phenolic fiber, polyetherester fiber, polylactic acid fiber, polycarbonate fiber and the like. Examples of the inorganic fibers include glass fibers, carbon fibers, ceramic fibers, and metal fibers.
本実施形態の塗液中には、従来に比して多量のエアロゲル粒子が含まれており、塗液中のエアロゲル粒子の含有量は20質量%以上である。より低密度の塗膜を得るという観点から、当該含有量は25質量%以上とすることができ、30質量%以上であってもよく、30質量%超であってもよい。なお、当該含有量の上限は特に制限されないが、エアロゲル粒子の分散性、良好な塗工性等の観点から、50質量%とすることができる。
塗 The coating liquid of the present embodiment contains a larger amount of airgel particles than in the past, and the content of airgel particles in the coating liquid is 20% by mass or more. From the viewpoint of obtaining a lower-density coating film, the content can be 25% by mass or more, may be 30% by mass or more, or may be more than 30% by mass. The upper limit of the content is not particularly limited, but may be 50% by mass from the viewpoint of the dispersibility of the airgel particles, good coating properties, and the like.
塗液中のバインダ樹脂の含有量は、エアロゲル粒子同士の結着性、塗膜の断熱性等の観点から、1質量%以上とすることができ、2質量%以上であってもよく、3質量%以上であってもよい。また、当該含有量は、10質量%以下とすることができるが、7質量%以下であってもよく、5質量%以下であってもよい。
The content of the binder resin in the coating liquid may be 1% by mass or more, and may be 2% by mass or more from the viewpoints of the binding property between the airgel particles and the heat insulating property of the coating film. It may be not less than mass%. Further, the content can be 10% by mass or less, but may be 7% by mass or less, or may be 5% by mass or less.
塗液中のバインダ樹脂の含有量は、例えば、エアロゲル粒子100質量部に対して、5質量部以上とすることができるが、7質量部以上であってもよく、10質量部以上であってもよく、12質量部以上であってもよい。これにより、エアロゲル粒子がバインダ樹脂によって強固に結着され易くなり、塗膜の強度が一層向上する。
The content of the binder resin in the coating liquid can be, for example, 5 parts by mass or more with respect to 100 parts by mass of the airgel particles, but may be 7 parts by mass or more, or 10 parts by mass or more. And may be 12 parts by mass or more. This makes it easier for the airgel particles to be firmly bound by the binder resin, further improving the strength of the coating film.
また、バインダ樹脂の含有量は、例えば、エアロゲル粒子100質量部に対して、20質量部以下とすることができるが、18質量部以下であってもよく、15質量部以下であってもよい。これにより、塗膜中のエアロゲル粒子の比率が高くなり、塗膜密度を低下することができ、また塗膜の断熱性が一層向上する。
Further, the content of the binder resin can be, for example, 20 parts by mass or less with respect to 100 parts by mass of the airgel particles, but may be 18 parts by mass or less, or may be 15 parts by mass or less. . Thereby, the ratio of the airgel particles in the coating film is increased, the density of the coating film can be reduced, and the heat insulating property of the coating film is further improved.
塗液中の繊維状物質の含有量は、塗液中での分散性、良好なアンカー機能の発現性等の観点から、0.01~30質量%とすることができるが、0.1~10質量%であってもよい。
The content of the fibrous substance in the coating liquid can be 0.01 to 30% by mass from the viewpoints of dispersibility in the coating liquid, good anchor function, and the like. It may be 10% by mass.
塗液中の繊維状物質の含有量は、例えば、エアロゲル粒子100質量部に対して、5質量部以上とすることができるが、7質量部以上であってもよく、9質量部以上であってもよい。これにより、繊維状物質によるアンカー効果が得られ易くなり、塗膜強度が一層向上する。
The content of the fibrous substance in the coating liquid can be, for example, 5 parts by mass or more with respect to 100 parts by mass of the airgel particles, but may be 7 parts by mass or more, or 9 parts by mass or more. You may. Thereby, the anchor effect by the fibrous substance is easily obtained, and the coating film strength is further improved.
また、繊維状物質の含有量は、例えば、エアロゲル粒子100質量部に対して、50質量部以下とすることができるが、35質量部以下であってもよく、25質量部以下であってもよく、20質量部以下であってもよく、15質量部以下であってもよい。これにより、塗膜中のエアロゲル粒子の比率が高くなり、塗膜の断熱性が一層向上する。
Further, the content of the fibrous substance can be, for example, 50 parts by mass or less based on 100 parts by mass of the airgel particles, but may be 35 parts by mass or less, or 25 parts by mass or less. The amount may be 20 parts by mass or less, or 15 parts by mass or less. Thereby, the ratio of the airgel particles in the coating film is increased, and the heat insulating property of the coating film is further improved.
増粘剤の含有量は、所望の塗液粘度(例えば、1000mPa・s以上)となるように適宜調整することができる。塗液の粘度はバインダ樹脂を配合することにより向上させることもできるため、その場合は必ずしも増粘剤を配合する必要はない。
含有 The content of the thickener can be appropriately adjusted so as to have a desired coating liquid viscosity (for example, 1000 mPa · s or more). Since the viscosity of the coating liquid can be improved by blending a binder resin, in such a case, it is not always necessary to blend a thickener.
塗液中の固形分全体に対するエアロゲル粒子の割合は、90体積%以上とすることができるが、95体積%以上であってもよく、98体積%以上であってもよい。また、塗液中の固形分全体に対するバインダ樹脂の割合は、3体積%以下とすることができるが、2.5体積%以下であってもよく、2体積%以下であってもよい。
割 合 The ratio of the airgel particles to the entire solid content in the coating liquid can be 90% by volume or more, but may be 95% by volume or more, or may be 98% by volume or more. In addition, the ratio of the binder resin to the entire solid content in the coating liquid can be 3% by volume or less, but may be 2.5% by volume or less, or may be 2% by volume or less.
液状媒体は水を主成分(例えば90質量%以上)として含んでいてもよい。水は撥水性のエアロゲル粒子が有する多孔質構造内に浸入し難いため、塗液化がより容易になる。ただし、液状媒体は、エアロゲル粒子とバインダ樹脂との混練性をより向上するために、有機溶媒を含んでいてもよい。液状媒体中の有機溶媒の含有量は、1質量%以上とすることができ、3質量%以上であってもよく、5質量%以上であってもよい。
The liquid medium may contain water as a main component (for example, 90% by mass or more). Water is less likely to penetrate into the porous structure of the water-repellent airgel particles, so that the application of the liquid becomes easier. However, the liquid medium may contain an organic solvent in order to further improve the kneading properties of the airgel particles and the binder resin. The content of the organic solvent in the liquid medium may be 1% by mass or more, may be 3% by mass or more, and may be 5% by mass or more.
塗液の比重は0.8以下とすることができるが、0.77以下であってもよく、0.75以下であってもよい。比重の下限は、クラックの発生を抑制しつつ塗膜を形成し易いという観点から、0.35とすることができ、0.6としてもよい。塗液の比重は、室温(10~30℃)環境で、ディスポーザブルシリンジを用いて測定することができる。具体的には、2.5mLのディスポーザブルシリンジに1.5mL以上の塗液を詰め、シリンジ内の空気を抜いた後に、シリンジ及び塗液の合計重量(A)を計測する。続いてシリンジから塗液を1.0mL押し出した後のシリンジ及びシリンジ内の塗液の合計重量(B)を計測する。そして(A)-(B)の重量差を塗液1.0mLあたりの重量として、塗液の比重を算出することができる。ただし、塗液の比重は、シリンジを用いた上記の方法の他、レーザー体積計、浮ひょう、比重計等によっても測定することができる。
比 The specific gravity of the coating liquid can be 0.8 or less, but may be 0.77 or less, or 0.75 or less. The lower limit of the specific gravity can be set to 0.35, and may be set to 0.6, from the viewpoint of easily forming a coating film while suppressing the occurrence of cracks. The specific gravity of the coating solution can be measured at room temperature (10 to 30 ° C.) using a disposable syringe. Specifically, a 2.5 mL disposable syringe is filled with 1.5 mL or more of the coating liquid, and after evacuating the air in the syringe, the total weight (A) of the syringe and the coating liquid is measured. Subsequently, the total weight (B) of the syringe and the coating liquid in the syringe after extruding 1.0 mL of the coating liquid from the syringe is measured. The specific gravity of the coating liquid can be calculated by setting the weight difference between (A) and (B) as the weight per 1.0 mL of the coating liquid. However, the specific gravity of the coating liquid can be measured by a laser volume meter, a float, a specific gravity meter, or the like, in addition to the above-described method using a syringe.
なお、本実施形態に係る塗液はエアロゲル粒子含有塗液と言うことができるが、粘度次第ではペースト状であってもよく、エアロゲル粒子含有ペーストと言うことができる。
The coating liquid according to the present embodiment can be referred to as an airgel particle-containing coating liquid, but may be in a paste form depending on the viscosity, and can be referred to as an airgel particle-containing paste.
塗液は、少なくともエアロゲル粒子、バインダ樹脂及び液状媒体を含む原料を、市販のミキサーを一種又は複数用いて撹拌(混合)することにより調製することができる。そのようなミキサーとしては、自転公転型ミキサー等の剪断撹拌機、遊星運動型ミキサー(プラネタリミキサー)等の低速剪断撹拌機、ホモミキサー等の高速剪断撹拌機などが挙げられる。
The coating liquid can be prepared by stirring (mixing) a raw material containing at least airgel particles, a binder resin and a liquid medium using one or more commercially available mixers. Examples of such a mixer include a shear stirrer such as a rotation-revolving mixer, a low-speed shear stirrer such as a planetary mixer (planetary mixer), and a high-speed shear stirrer such as a homomixer.
自転公転型ミキサーを用いる場合の撹拌条件は、攪拌速度を500~1500rpmとし、攪拌時間を1~60分間とすることができる。遊星運動型ミキサーを用いる場合の撹拌条件は、攪拌速度を8~200rpmとし、攪拌時間を1~120分間とすることができる。ホモミキサーはこれらのミキサーによる本撹拌と組み合わせて用いることが好ましく、特に当該本撹拌の予備撹拌手段として用いることが好ましい。例えば、本実施形態の撹拌は、原料を高速剪断撹拌機により撹拌する高速剪断撹拌工程と、その後の低速剪断撹拌機により撹拌する低速剪断撹拌工程とを備えることができる。ホモミキサーを予備撹拌手段として用いる場合の撹拌条件は、攪拌速度を1000~3000rpmとし、攪拌時間を1~20分間とすることができる。
撹 拌 As for the stirring conditions when using a rotation and revolution type mixer, the stirring speed can be 500 to 1500 rpm, and the stirring time can be 1 to 60 minutes. The stirring conditions when using a planetary mixer can be a stirring speed of 8 to 200 rpm and a stirring time of 1 to 120 minutes. The homomixer is preferably used in combination with the main stirring by these mixers, and particularly preferably used as a preliminary stirring means for the main stirring. For example, the stirring of the present embodiment can include a high-speed shearing and stirring step of stirring the raw material by a high-speed shearing stirrer and a subsequent low-speed shearing and stirring step of stirring by a low-speed shearing stirrer. When a homomixer is used as the preliminary stirring means, the stirring conditions may be a stirring speed of 1000 to 3000 rpm and a stirring time of 1 to 20 minutes.
自転公転型ミキサーとしては、あわとり練太郎シリーズ(株式会社シンキー製、製品名)、ME-N300BR(株式会社ビートセンシング製、製品名)、ハイマージャ(アズワン株式会社製、製品名)等が挙げられる。遊星運動型ミキサーとしては、プラネタリーミキサーシリーズ(株式会社井上製作所製、製品名)、ピーディーミキサーシリーズ(株式会社井上製作所製、製品名)、ハイビスミックスシリーズ(プライミクス株式会社製、製品名)、ハイビスディスパーミックスシリーズ(プライミクス株式会社製、製品名)等が挙げられる。ホモミキサーとしては、L5シリーズ(SILVERSON製、製品名)、ホモミクサーMARKIIシリーズ(プライミクス株式会社製、製品名)等が挙げられる。
Examples of the rotation-revolution type mixer include the Awatori Rentaro series (Shinky Co., Ltd., product name), ME-N300BR (Beat Sensing Co., Ltd., product name), Hi-Maja (AS-ONE Co., Ltd., product name) and the like. Can be Planetary mixers series include Planetary Mixer Series (product name, Inoue Manufacturing Co., Ltd.), PD Mixer Series (product name, Inoue Manufacturing Co., Ltd.), Hibis Mix Series (product name, manufactured by Primix Co., Ltd.), Hibis Dispermix series (product name, manufactured by Primix Corporation) and the like. Examples of the homomixer include an L5 series (manufactured by SILVERSON, product name) and a homomixer MARKII series (manufactured by Primix, product name).
なお、エアロゲル粒子が有する空孔内に液状の成分(バインダ樹脂、液状媒体等)が多く入り込むと、塗液比重が上昇し、その結果塗膜の密度が大きくなる。このことを抑制するべく、塗液の調製に当たっては、使用するエアロゲル粒子の特性に応じて撹拌条件を調整したり(過度な条件での攪拌を行わない)、あるいはバインダ樹脂の種類を変更したりする(液状の成分の粘度を上げる、エアロゲル粒子に対して親和性の低いバインダ樹脂を選択する)ことが好ましい。
多 く If a lot of liquid components (binder resin, liquid medium, etc.) enter the pores of the airgel particles, the specific gravity of the coating liquid increases, and as a result, the density of the coating film increases. In order to suppress this, when preparing the coating liquid, adjust the stirring conditions according to the characteristics of the airgel particles to be used (do not perform stirring under excessive conditions), or change the type of binder resin. (It is preferable to increase the viscosity of the liquid component and to select a binder resin having low affinity for the airgel particles).
<塗膜の製造方法及び塗膜>
塗膜は、エアロゲル粒子、バインダ樹脂及び液状媒体を含む上記塗液から、液状媒体を除去することで形成することができる。より具体的には、塗膜の製造方法(塗膜形成方法)は、上述の塗液を対象物上に塗布する工程と、対象物上に塗布された塗液から液状媒体を除去する工程と、を備えることができる。 <Production method and coating film>
The coating film can be formed by removing the liquid medium from the coating liquid containing the airgel particles, the binder resin, and the liquid medium. More specifically, a method for producing a coating film (a method for forming a coating film) includes a step of applying the above-described coating liquid on an object, and a step of removing a liquid medium from the coating liquid applied on the object. , Can be provided.
塗膜は、エアロゲル粒子、バインダ樹脂及び液状媒体を含む上記塗液から、液状媒体を除去することで形成することができる。より具体的には、塗膜の製造方法(塗膜形成方法)は、上述の塗液を対象物上に塗布する工程と、対象物上に塗布された塗液から液状媒体を除去する工程と、を備えることができる。 <Production method and coating film>
The coating film can be formed by removing the liquid medium from the coating liquid containing the airgel particles, the binder resin, and the liquid medium. More specifically, a method for producing a coating film (a method for forming a coating film) includes a step of applying the above-described coating liquid on an object, and a step of removing a liquid medium from the coating liquid applied on the object. , Can be provided.
塗液を対象物上に塗布する方法としては特に制限されず、例えばディップコート、スプレーコート、スピンコート、ロールコート等が挙げられる。塗膜の形成に際しては、塗布された塗液に対し、加熱(例えば、40~150℃)処理、減圧(例えば、10000Pa以下)処理、又はそれらの両処理を行うことで、塗液から液状媒体を除去すればよい。
方法 The method of applying the coating liquid on the object is not particularly limited, and examples thereof include dip coating, spray coating, spin coating, and roll coating. When forming a coating film, the applied coating liquid is subjected to a heating (for example, 40 to 150 ° C.) treatment, a reduced pressure (for example, 10,000 Pa or less) treatment, or both of these treatments, so that the coating liquid is converted to a liquid medium. May be removed.
上記工程により、エアロゲル粒子及びバインダ樹脂を含む塗膜を得ることができる。
に よ り By the above steps, a coating film containing the airgel particles and the binder resin can be obtained.
塗膜中のエアロゲル粒子の含有量は、例えば、80質量%以上とすることができるが、85質量%以上であってもよく、90質量%以上であってもよい。これにより、塗膜密度が低下し、塗膜の断熱性が一層向上する。塗膜中のエアロゲル粒子の含有量は、例えば、95質量%以下とすることができるが、93質量%以下であってもよい。これにより、塗膜が形成し易くなる傾向がある。
含有 The content of the airgel particles in the coating film can be, for example, 80% by mass or more, but may be 85% by mass or more, or 90% by mass or more. As a result, the coating film density is reduced, and the heat insulating properties of the coating film are further improved. The content of the airgel particles in the coating film can be, for example, 95% by mass or less, but may be 93% by mass or less. Thereby, a coating film tends to be easily formed.
塗膜中のエアロゲル粒子の割合は、90体積%以上とすることができるが、95体積%以上であってもよく、98体積%以上であってもよい。また、塗膜中のバインダ樹脂の割合は、3体積%以下とすることができるが、2.5体積%以下であってもよく、2体積%以下であってもよい。
割 合 The proportion of the airgel particles in the coating film can be 90% by volume or more, but may be 95% by volume or more, or 98% by volume or more. Further, the ratio of the binder resin in the coating film can be 3% by volume or less, but may be 2.5% by volume or less, or may be 2% by volume or less.
本実施形態の塗液を用いることにより、非常に軽質な塗膜(エアロゲル塗膜)を得ることができる。塗膜の密度は0.4g/cm3以下とすることができるが、0.37g/cm3以下であってもよく、0.35g/cm3以下であってもよい。塗膜の密度の下限は特に制限されないが、良好な塗膜強度を得易いという観点から、0.1g/cm3とすることができ、0.2g/cm3としてもよい。塗膜の密度は、JIS Z 8827:2012に記載の「液中ひょう量法による密度及び比重の測定方法」、あるいは「幾何学的測定による密度及び比重の測定方法」により測定することができる。
By using the coating liquid of the present embodiment, a very light coating film (airgel coating film) can be obtained. The density of the coating may be 0.4 g / cm 3 or less, but may be 0.37 g / cm 3 or less, or 0.35 g / cm 3 or less. Although the lower limit of the density of the coating film is not particularly limited, it may be 0.1 g / cm 3 or may be 0.2 g / cm 3 from the viewpoint of easily obtaining good coating strength. The density of the coating film can be measured by the “method of measuring density and specific gravity by weighing in liquid” or “the measuring method of density and specific gravity by geometrical measurement” described in JIS Z 8827: 2012.
塗膜の厚さは特に制限されず、例えば、0.01~5mmとすることができる。
The thickness of the coating film is not particularly limited, and may be, for example, 0.01 to 5 mm.
対象物を構成する材料としては特に制限されず、金属、セラミック、ガラス、樹脂、これらの複合材料等が挙げられる。対象物の形態としては、使用する目的又は材料に応じて適宜選択することができ、ブロック状、シート状、パウダー状、繊維状等が挙げられる。
材料 The material constituting the object is not particularly limited, and examples thereof include metal, ceramic, glass, resin, and composite materials thereof. The form of the target object can be appropriately selected according to the purpose or material used, and includes a block shape, a sheet shape, a powder shape, a fiber shape, and the like.
塗膜は、エアロゲルに由来する優れた断熱性、耐熱性、難燃性等を有する。このような利点から、当該塗膜を、極低温容器、宇宙分野、建築分野、自動車分野、家電分野、半導体分野、産業用設備等における断熱材としての用途等に適用できる。なお、当該塗膜は、断熱材としての用途の他に、撥水材、吸音材、静振材、触媒担持材等としても利用することができる。
The coating film has excellent heat insulation, heat resistance, flame retardancy, etc. derived from aerogel. Due to such advantages, the coating film can be applied to a cryogenic container, a space field, an architectural field, an automobile field, a home appliance field, a semiconductor field, a heat insulating material in industrial equipment, and the like. The coating film can be used not only as a heat insulating material but also as a water repellent material, a sound absorbing material, a vibration damping material, a catalyst supporting material, and the like.
次に、下記の実施例により本発明をさらに詳しく説明するが、これらの実施例は本発明を制限するものではない。
Next, the present invention will be described in more detail with reference to the following examples, but these examples do not limit the present invention.
(エアロゲル粒子Aの作製)
シリカ粒子含有原料としてPL-2L(扶桑化学工業株式会社製、製品名)を100.0質量部、水を80.0質量部、酸触媒として酢酸を0.5質量部、カチオン性界面活性剤として臭化セチルトリメチルアンモニウム(和光純薬工業株式会社製)を1.0質量部、及び熱加水分解性化合物として尿素を150.0質量部混合し、これにケイ素化合物としてメチルトリメトキシシラン(信越化学工業株式会社製、製品名:KBM-13)を60.0質量部、ジメチルジメトキシシラン(信越化学工業株式会社製、製品名:KBM-22)を20.0質量部、上記一般式(B)で表される構造を有する両末端2官能アルコキシ変性ポリシロキサン化合物(以下、「ポリシロキサン化合物X」という)を20.0質量部加え、25℃で2時間反応させてゾルを得た。得られたゾルを60℃でゲル化した後、60℃で48時間熟成して湿潤ゲルを得た。 (Preparation of airgel particles A)
100.0 parts by mass of PL-2L (product name, manufactured by Fuso Chemical Industry Co., Ltd.) as a silica particle-containing raw material, 80.0 parts by mass of water, 0.5 parts by mass of acetic acid as an acid catalyst, a cationic surfactant 1.0 part by mass of cetyltrimethylammonium bromide (manufactured by Wako Pure Chemical Industries, Ltd.) and 150.0 parts by mass of urea as a thermally hydrolyzable compound, and methyltrimethoxysilane (Shin-Etsu) as a silicon compound 60.0 parts by mass of Chemical Industry Co., Ltd., product name: KBM-13), 20.0 parts by mass of dimethyldimethoxysilane (Shin-Etsu Chemical Co., Ltd., product name: KBM-22), and the above-mentioned general formula (B) 20.0 parts by mass of a bifunctional alkoxy-modified polysiloxane compound having a structure represented by the formula (hereinafter referred to as “polysiloxane compound X”), Obtain a sol by. After gelling the obtained sol at 60 ° C., it was aged at 60 ° C. for 48 hours to obtain a wet gel.
シリカ粒子含有原料としてPL-2L(扶桑化学工業株式会社製、製品名)を100.0質量部、水を80.0質量部、酸触媒として酢酸を0.5質量部、カチオン性界面活性剤として臭化セチルトリメチルアンモニウム(和光純薬工業株式会社製)を1.0質量部、及び熱加水分解性化合物として尿素を150.0質量部混合し、これにケイ素化合物としてメチルトリメトキシシラン(信越化学工業株式会社製、製品名:KBM-13)を60.0質量部、ジメチルジメトキシシラン(信越化学工業株式会社製、製品名:KBM-22)を20.0質量部、上記一般式(B)で表される構造を有する両末端2官能アルコキシ変性ポリシロキサン化合物(以下、「ポリシロキサン化合物X」という)を20.0質量部加え、25℃で2時間反応させてゾルを得た。得られたゾルを60℃でゲル化した後、60℃で48時間熟成して湿潤ゲルを得た。 (Preparation of airgel particles A)
100.0 parts by mass of PL-2L (product name, manufactured by Fuso Chemical Industry Co., Ltd.) as a silica particle-containing raw material, 80.0 parts by mass of water, 0.5 parts by mass of acetic acid as an acid catalyst, a cationic surfactant 1.0 part by mass of cetyltrimethylammonium bromide (manufactured by Wako Pure Chemical Industries, Ltd.) and 150.0 parts by mass of urea as a thermally hydrolyzable compound, and methyltrimethoxysilane (Shin-Etsu) as a silicon compound 60.0 parts by mass of Chemical Industry Co., Ltd., product name: KBM-13), 20.0 parts by mass of dimethyldimethoxysilane (Shin-Etsu Chemical Co., Ltd., product name: KBM-22), and the above-mentioned general formula (B) 20.0 parts by mass of a bifunctional alkoxy-modified polysiloxane compound having a structure represented by the formula (hereinafter referred to as “polysiloxane compound X”), Obtain a sol by. After gelling the obtained sol at 60 ° C., it was aged at 60 ° C. for 48 hours to obtain a wet gel.
なお、上記「ポリシロキサン化合物X」は次のようにして合成した。まず、撹拌機、温度計及びジムロート冷却管を備えた1リットルの3つ口フラスコにて、両末端にシラノール基を有するジメチルポリシロキサンXC96-723(モメンティブ・パフォーマンス・マテリアルズ・ジャパン合同会社製、製品名)を100.0質量部、メチルトリメトキシシランを181.3質量部及びt-ブチルアミンを0.50質量部混合し、30℃で5時間反応させた。その後、この反応液を、1.3kPaの減圧下、140℃で2時間加熱し、揮発分を除去することで、両末端2官能アルコキシ変性ポリシロキサン化合物(ポリシロキサン化合物X)を得た。
The "polysiloxane compound X" was synthesized as follows. First, in a 1-liter three-necked flask equipped with a stirrer, a thermometer and a Dimroth condenser, dimethylpolysiloxane XC96-723 having silanol groups at both ends (manufactured by Momentive Performance Materials Japan GK. (Product name), 101.3 parts by mass of methyltrimethoxysilane, and 0.50 parts by mass of t-butylamine were mixed and reacted at 30 ° C. for 5 hours. Thereafter, this reaction solution was heated at 140 ° C. for 2 hours under a reduced pressure of 1.3 kPa to remove volatile components, thereby obtaining a bifunctional alkoxy-modified polysiloxane compound at both ends (polysiloxane compound X).
その後、得られた湿潤ゲルをプラスチック製ボトルに移し、密閉後、エクストリームミル(アズワン株式会社製、MX-1000XTS)を用いて、27,000rpmで10分間粉砕し、粒子状の湿潤ゲルを得た。得られた粒子状の湿潤ゲルをメタノール2500.0質量部に浸漬し、25℃で24時間かけて洗浄を行った。この洗浄操作を、新しいメタノールに交換しながら合計3回行った。次に、洗浄した粒子状の湿潤ゲルを、低表面張力溶媒であるヘプタン2500.0質量部に浸漬し、25℃で24時間かけて溶媒置換を行った。この溶媒置換操作を、新しいヘプタンに交換しながら合計3回行った。洗浄及び溶媒置換された粒子状の湿潤ゲルを、常圧下にて、40℃で96時間乾燥し、その後さらに150℃で2時間乾燥した。最後に、ふるい(東京スクリーン株式会社製、目開き45μm、線径32μm)にかけ、上記一般式(3)、(4)及び(5)で表される構造を有するエアロゲル粒子Aを得た。
Thereafter, the obtained wet gel was transferred to a plastic bottle, sealed, and then pulverized for 10 minutes at 27,000 rpm using an extreme mill (manufactured by As One Corporation, MX-1000XTS) to obtain a particulate wet gel. . The obtained particulate wet gel was immersed in 2500.0 parts by mass of methanol and washed at 25 ° C. for 24 hours. This washing operation was performed three times in total while exchanging with fresh methanol. Next, the washed particulate wet gel was immersed in 2500.0 parts by mass of heptane as a low surface tension solvent, and the solvent was replaced at 25 ° C. for 24 hours. This solvent replacement operation was performed a total of three times while exchanging for new heptane. The washed and solvent-substituted particulate wet gel was dried at 40 ° C. for 96 hours under normal pressure, and further dried at 150 ° C. for 2 hours. Finally, it was sieved (Tokyo Screen Co., Ltd., mesh size: 45 μm, wire diameter: 32 μm) to obtain the airgel particles A having the structures represented by the general formulas (3), (4) and (5).
(エアロゲル粒子Bの準備)
エアロゲル粒子BとしてJIOS AeroVa(登録商標、JIOS AEROGEL CORPORATION社製、製品名)を準備した。 (Preparation of airgel particles B)
JIOS AeroVa (registered trademark, manufactured by JIOS AEROGEL CORPORATION, product name) was prepared as the airgel particles B.
エアロゲル粒子BとしてJIOS AeroVa(登録商標、JIOS AEROGEL CORPORATION社製、製品名)を準備した。 (Preparation of airgel particles B)
JIOS AeroVa (registered trademark, manufactured by JIOS AEROGEL CORPORATION, product name) was prepared as the airgel particles B.
(エアロゲル粒子の比表面積測定)
エアロゲル粒子のBET比表面積を、ガス吸着量測定装置(カンタクローム・インスツルメンツ・ジャパン合同会社製、Autosorb-iQ(Autosorbは登録商標))を用いて測定した。エアロゲル粒子Aの比表面積は125m2/g、エアロゲル粒子Bの比表面積は716m2/gであった。 (Specific surface area measurement of airgel particles)
The BET specific surface area of the airgel particles was measured using a gas adsorption amount measurement device (Autosorb-iQ (Autosorb is a registered trademark) manufactured by Kantachrome Instruments Japan GK). The specific surface area of the airgel particles A was 125 m 2 / g, and the specific surface area of the airgel particles B was 716 m 2 / g.
エアロゲル粒子のBET比表面積を、ガス吸着量測定装置(カンタクローム・インスツルメンツ・ジャパン合同会社製、Autosorb-iQ(Autosorbは登録商標))を用いて測定した。エアロゲル粒子Aの比表面積は125m2/g、エアロゲル粒子Bの比表面積は716m2/gであった。 (Specific surface area measurement of airgel particles)
The BET specific surface area of the airgel particles was measured using a gas adsorption amount measurement device (Autosorb-iQ (Autosorb is a registered trademark) manufactured by Kantachrome Instruments Japan GK). The specific surface area of the airgel particles A was 125 m 2 / g, and the specific surface area of the airgel particles B was 716 m 2 / g.
(エアロゲル粒子の平均粒子径測定)
エタノールに、エアロゲル粒子の含有量が0.5質量%となるように添加し、これに50Wの超音波ホモジナイザーで20分間振動を与えることで分散液を調製した。得られた分散液10mLをMicrotrac MT3000(日機装株式会社製、製品名)に注入し、25℃で、屈折率1.3、吸収0として粒子径を測定した。そして、得られた粒子径分布における積算値50%(体積基準)での粒子径を平均粒子径D50とした。エアロゲル粒子Aの平均粒子径D50は20μm、エアロゲル粒子Bの平均粒子径D50は17μmであった。 (Average particle size measurement of airgel particles)
Ethanol was added so that the content of the airgel particles was 0.5% by mass, and this was vibrated with a 50 W ultrasonic homogenizer for 20 minutes to prepare a dispersion. 10 mL of the obtained dispersion was injected into Microtrac MT3000 (manufactured by Nikkiso Co., Ltd., product name), and the particle size was measured at 25 ° C. with a refractive index of 1.3 and an absorption of 0. The particle diameter at an integrated value of 50% (by volume) in the obtained particle diameter distribution was defined as an average particle diameter D50. The average particle diameter D50 of the airgel particles A was 20 μm, and the average particle diameter D50 of the airgel particles B was 17 μm.
エタノールに、エアロゲル粒子の含有量が0.5質量%となるように添加し、これに50Wの超音波ホモジナイザーで20分間振動を与えることで分散液を調製した。得られた分散液10mLをMicrotrac MT3000(日機装株式会社製、製品名)に注入し、25℃で、屈折率1.3、吸収0として粒子径を測定した。そして、得られた粒子径分布における積算値50%(体積基準)での粒子径を平均粒子径D50とした。エアロゲル粒子Aの平均粒子径D50は20μm、エアロゲル粒子Bの平均粒子径D50は17μmであった。 (Average particle size measurement of airgel particles)
Ethanol was added so that the content of the airgel particles was 0.5% by mass, and this was vibrated with a 50 W ultrasonic homogenizer for 20 minutes to prepare a dispersion. 10 mL of the obtained dispersion was injected into Microtrac MT3000 (manufactured by Nikkiso Co., Ltd., product name), and the particle size was measured at 25 ° C. with a refractive index of 1.3 and an absorption of 0. The particle diameter at an integrated value of 50% (by volume) in the obtained particle diameter distribution was defined as an average particle diameter D50. The average particle diameter D50 of the airgel particles A was 20 μm, and the average particle diameter D50 of the airgel particles B was 17 μm.
(実施例1)
泡とり練太郎ARV-310(株式会社シンキー製、製品名)の専用容器に、ヒドロキシプロピルメチルセルロースとしてマーポローズMP30000(松本油脂株式会社製、製品名、比重1.2)を0.50g、イソプロピルアルコール(比重0.78)を1g、水を10g、及びエアロゲル粒子Aを5.00g投入した。そして容器の蓋を閉め、撹拌速度1000rpmで10分間撹拌することで、実施例1の塗液を得た。 (Example 1)
0.50 g of Marpolose MP30000 (manufactured by Matsumoto Yushi Co., Ltd., product name, specific gravity: 1.2) as hydroxypropyl methylcellulose in a dedicated container of Awatori Nerita ARV-310 (manufactured by Shinky Inc., product name), 1 g of specific gravity 0.78), 10 g of water, and 5.00 g of airgel particles A were added. Then, the lid of the container was closed, and the mixture was stirred at a stirring speed of 1000 rpm for 10 minutes to obtain a coating liquid of Example 1.
泡とり練太郎ARV-310(株式会社シンキー製、製品名)の専用容器に、ヒドロキシプロピルメチルセルロースとしてマーポローズMP30000(松本油脂株式会社製、製品名、比重1.2)を0.50g、イソプロピルアルコール(比重0.78)を1g、水を10g、及びエアロゲル粒子Aを5.00g投入した。そして容器の蓋を閉め、撹拌速度1000rpmで10分間撹拌することで、実施例1の塗液を得た。 (Example 1)
0.50 g of Marpolose MP30000 (manufactured by Matsumoto Yushi Co., Ltd., product name, specific gravity: 1.2) as hydroxypropyl methylcellulose in a dedicated container of Awatori Nerita ARV-310 (manufactured by Shinky Inc., product name), 1 g of specific gravity 0.78), 10 g of water, and 5.00 g of airgel particles A were added. Then, the lid of the container was closed, and the mixture was stirred at a stirring speed of 1000 rpm for 10 minutes to obtain a coating liquid of Example 1.
(実施例2)
100mLポリカップにマーポローズMP30000を5.00g、イソプロピルアルコールを10gとり、薬さじによりかき混ぜることでMP30000の分散液を調製した。次に、500mLポリカップに純水を100gとり、ホモミキサーL5R(SILVERSON製、製品名)により純水を2000rpmで撹拌しながら、上記の分散液を全量添加した。撹拌時間は3分間とした。これによりベース液を調製した。 (Example 2)
5.00 g of Marpolose MP30000 and 10 g of isopropyl alcohol were placed in a 100 mL polycup, and stirred with a spoonful of scoop to prepare a dispersion of MP30000. Next, 100 g of pure water was placed in a 500 mL polycup, and the whole amount of the above dispersion was added while stirring the pure water at 2000 rpm using a homomixer L5R (manufactured by SILVERSON, product name). The stirring time was 3 minutes. Thus, a base solution was prepared.
100mLポリカップにマーポローズMP30000を5.00g、イソプロピルアルコールを10gとり、薬さじによりかき混ぜることでMP30000の分散液を調製した。次に、500mLポリカップに純水を100gとり、ホモミキサーL5R(SILVERSON製、製品名)により純水を2000rpmで撹拌しながら、上記の分散液を全量添加した。撹拌時間は3分間とした。これによりベース液を調製した。 (Example 2)
5.00 g of Marpolose MP30000 and 10 g of isopropyl alcohol were placed in a 100 mL polycup, and stirred with a spoonful of scoop to prepare a dispersion of MP30000. Next, 100 g of pure water was placed in a 500 mL polycup, and the whole amount of the above dispersion was added while stirring the pure water at 2000 rpm using a homomixer L5R (manufactured by SILVERSON, product name). The stirring time was 3 minutes. Thus, a base solution was prepared.
次に、ハイビスミックス2P-03型(プライミクス株式会社製、製品名)の受け容器に上記のベース液を全量入れ、100rpmで撹拌しながら、エアロゲル粒子Aを50g添加した。撹拌時間は60分間とした。これにより実施例2の塗液を得た。
Next, the entire amount of the above base liquid was put into a receiving container of Hibismix 2P-03 type (manufactured by Primix Co., Ltd.), and 50 g of airgel particles A was added while stirring at 100 rpm. The stirring time was 60 minutes. Thus, a coating liquid of Example 2 was obtained.
(その他の実施例及び比較例)
塗液の配合原料及び撹拌方式を表1又は2に示すように変更したこと以外は、実施例1と同様にして塗液を調製した。 (Other Examples and Comparative Examples)
A coating liquid was prepared in the same manner as in Example 1, except that the raw materials and the stirring method of the coating liquid were changed as shown in Table 1 or 2.
塗液の配合原料及び撹拌方式を表1又は2に示すように変更したこと以外は、実施例1と同様にして塗液を調製した。 (Other Examples and Comparative Examples)
A coating liquid was prepared in the same manner as in Example 1, except that the raw materials and the stirring method of the coating liquid were changed as shown in Table 1 or 2.
表1及び2中、撹拌手段A~Cの詳細は以下のとおりである。
A:あわとり練太郎 ARV-310(株式会社シンキー製、製品名)
B:ホモミキサー L5R(SILVERSON製、製品名)
C:プラネタリミキサー ハイビスミックス2P-03(プライミクス株式会社製、製品名) In Tables 1 and 2, details of the stirring means A to C are as follows.
A: Awatori Naritaro ARV-310 (Shinky Co., Ltd., product name)
B: Homomixer L5R (SILVERSON, product name)
C: Planetary mixer Hibismix 2P-03 (Primix Corporation, product name)
A:あわとり練太郎 ARV-310(株式会社シンキー製、製品名)
B:ホモミキサー L5R(SILVERSON製、製品名)
C:プラネタリミキサー ハイビスミックス2P-03(プライミクス株式会社製、製品名) In Tables 1 and 2, details of the stirring means A to C are as follows.
A: Awatori Naritaro ARV-310 (Shinky Co., Ltd., product name)
B: Homomixer L5R (SILVERSON, product name)
C: Planetary mixer Hibismix 2P-03 (Primix Corporation, product name)
(各種評価)
各例にて得られた塗液について以下の評価を行った。評価結果を表3に示す。 (Various evaluations)
The following evaluation was performed on the coating liquid obtained in each example. Table 3 shows the evaluation results.
各例にて得られた塗液について以下の評価を行った。評価結果を表3に示す。 (Various evaluations)
The following evaluation was performed on the coating liquid obtained in each example. Table 3 shows the evaluation results.
(塗液分散性評価)
各例にて得られた塗液をメスシリンダー様の縦長のガラス容器に入れ、容器に蓋をした。その状態で60分間静置した後、塗液の状態を目視にて観察した。評価基準は以下のとおりとした。
良好:白濁したペースト状であった。
不良:液状の成分とエアロゲル粒子とが分離し、塗液全体の1体積%以上の上澄みが生じていた。 (Evaluation of coating liquid dispersibility)
The coating solution obtained in each case was placed in a vertically long glass container like a measuring cylinder, and the container was covered. After standing in that state for 60 minutes, the state of the coating liquid was visually observed. The evaluation criteria were as follows.
Good: A cloudy paste was formed.
Poor: The liquid component and the airgel particles were separated, and a supernatant of 1% by volume or more of the entire coating liquid was generated.
各例にて得られた塗液をメスシリンダー様の縦長のガラス容器に入れ、容器に蓋をした。その状態で60分間静置した後、塗液の状態を目視にて観察した。評価基準は以下のとおりとした。
良好:白濁したペースト状であった。
不良:液状の成分とエアロゲル粒子とが分離し、塗液全体の1体積%以上の上澄みが生じていた。 (Evaluation of coating liquid dispersibility)
The coating solution obtained in each case was placed in a vertically long glass container like a measuring cylinder, and the container was covered. After standing in that state for 60 minutes, the state of the coating liquid was visually observed. The evaluation criteria were as follows.
Good: A cloudy paste was formed.
Poor: The liquid component and the airgel particles were separated, and a supernatant of 1% by volume or more of the entire coating liquid was generated.
(塗液比重測定)
各例で得られた塗液の比重をディスポーザブルシリンジ(テルモ株式会社製、容量2.5mL)を用いて測定した。具体的には、室温(10~30℃)環境で、シリンジからプランジャーを外し、塗液内に気泡が入らないように薬さじを用いてシリンジに塗液を詰め、プランジャーを再度セットしてシリンジ先端の気泡を抜いた。電子天秤により、塗液を含むシリンジ全体の重量と、塗液を1mL吐出した後の重量との差を塗液1mL当たりの重量とし、塗液の比重を算出した。 (Measurement of coating liquid specific gravity)
The specific gravity of the coating liquid obtained in each example was measured using a disposable syringe (manufactured by Terumo Corporation, capacity: 2.5 mL). Specifically, at room temperature (10 to 30 ° C), remove the plunger from the syringe, fill the syringe with a spoon using a spoon so that air bubbles do not enter the coating solution, and set the plunger again. To remove air bubbles at the tip of the syringe. Using an electronic balance, the difference between the weight of the entire syringe including the coating liquid and the weight after discharging 1 mL of the coating liquid was defined as the weight per 1 mL of the coating liquid, and the specific gravity of the coating liquid was calculated.
各例で得られた塗液の比重をディスポーザブルシリンジ(テルモ株式会社製、容量2.5mL)を用いて測定した。具体的には、室温(10~30℃)環境で、シリンジからプランジャーを外し、塗液内に気泡が入らないように薬さじを用いてシリンジに塗液を詰め、プランジャーを再度セットしてシリンジ先端の気泡を抜いた。電子天秤により、塗液を含むシリンジ全体の重量と、塗液を1mL吐出した後の重量との差を塗液1mL当たりの重量とし、塗液の比重を算出した。 (Measurement of coating liquid specific gravity)
The specific gravity of the coating liquid obtained in each example was measured using a disposable syringe (manufactured by Terumo Corporation, capacity: 2.5 mL). Specifically, at room temperature (10 to 30 ° C), remove the plunger from the syringe, fill the syringe with a spoon using a spoon so that air bubbles do not enter the coating solution, and set the plunger again. To remove air bubbles at the tip of the syringe. Using an electronic balance, the difference between the weight of the entire syringe including the coating liquid and the weight after discharging 1 mL of the coating liquid was defined as the weight per 1 mL of the coating liquid, and the specific gravity of the coating liquid was calculated.
(成膜性評価)
各例で得られた塗液を用いて塗膜を形成した。具体的には、塗液を、金属ヘラを用いて、厚みが2mmとなるようにアルミ箔上に塗布した。そして120℃で1時間加熱することで塗液から液状媒体を除去し、塗膜を得た。得られた塗膜を目視にて観察し、以下の評価基準に従って評価した。
良好:クラックのない良好な外観を有していた。
不良:クラックが発生していた。 (Evaluation of film formability)
A coating film was formed using the coating liquid obtained in each example. Specifically, the coating liquid was applied on an aluminum foil using a metal spatula so as to have a thickness of 2 mm. Then, the liquid medium was removed from the coating liquid by heating at 120 ° C. for 1 hour to obtain a coating film. The obtained coating film was visually observed and evaluated according to the following evaluation criteria.
Good: had a good appearance without cracks.
Poor: cracks occurred.
各例で得られた塗液を用いて塗膜を形成した。具体的には、塗液を、金属ヘラを用いて、厚みが2mmとなるようにアルミ箔上に塗布した。そして120℃で1時間加熱することで塗液から液状媒体を除去し、塗膜を得た。得られた塗膜を目視にて観察し、以下の評価基準に従って評価した。
良好:クラックのない良好な外観を有していた。
不良:クラックが発生していた。 (Evaluation of film formability)
A coating film was formed using the coating liquid obtained in each example. Specifically, the coating liquid was applied on an aluminum foil using a metal spatula so as to have a thickness of 2 mm. Then, the liquid medium was removed from the coating liquid by heating at 120 ° C. for 1 hour to obtain a coating film. The obtained coating film was visually observed and evaluated according to the following evaluation criteria.
Good: had a good appearance without cracks.
Poor: cracks occurred.
(塗膜密度測定)
上記の成膜性評価で得られた塗膜の密度を測定した。具体的には、得られた塗膜を3cm×3cmにカットして測定サンプルとし、水温20℃の水槽を備えた比重計(アルファーミラージュ株式会社製、MDS-300)を用いて、測定サンプルの空中及び水中での重量を測定し、塗膜の比重を得た。 (Measurement of coating film density)
The density of the coating film obtained in the above evaluation of the film forming property was measured. Specifically, the obtained coating film was cut into a size of 3 cm × 3 cm to obtain a measurement sample, and the measurement sample was measured using a hydrometer (MDS-300, manufactured by Alpha Mirage Co., Ltd.) equipped with a water tank having a water temperature of 20 ° C. The weight in the air and in the water was measured to obtain the specific gravity of the coating film.
上記の成膜性評価で得られた塗膜の密度を測定した。具体的には、得られた塗膜を3cm×3cmにカットして測定サンプルとし、水温20℃の水槽を備えた比重計(アルファーミラージュ株式会社製、MDS-300)を用いて、測定サンプルの空中及び水中での重量を測定し、塗膜の比重を得た。 (Measurement of coating film density)
The density of the coating film obtained in the above evaluation of the film forming property was measured. Specifically, the obtained coating film was cut into a size of 3 cm × 3 cm to obtain a measurement sample, and the measurement sample was measured using a hydrometer (MDS-300, manufactured by Alpha Mirage Co., Ltd.) equipped with a water tank having a water temperature of 20 ° C. The weight in the air and in the water was measured to obtain the specific gravity of the coating film.
Claims (7)
- エアロゲル粒子、バインダ樹脂及び液状媒体を含み、前記エアロゲル粒子の含有量が20質量%以上である、塗液。 (4) A coating liquid containing airgel particles, a binder resin, and a liquid medium, wherein the content of the airgel particles is 20% by mass or more.
- 前記液状媒体が水を含む、請求項1に記載の塗液。 The coating liquid according to claim 1, wherein the liquid medium contains water.
- 前記液状媒体がさらに有機溶媒を含む、請求項2に記載の塗液。 The coating liquid according to claim 2, wherein the liquid medium further contains an organic solvent.
- 前記バインダ樹脂が、エポキシ樹脂、シリコーン樹脂、フェノール樹脂、尿素樹脂、メラミン樹脂、ポリウレタン樹脂、ポリエチレン樹脂、ポリプロピレン樹脂、ポリスチレン樹脂、ポリエステル樹脂、アクリル樹脂、ポリ塩化ビニル樹脂、ポリ酢酸ビニル樹脂、ポリアミド樹脂、ポリイミド樹脂、セルロース系樹脂、及びポリビニル系樹脂からなる群より選択される少なくとも一種を含む、請求項1~3のいずれか一項に記載の塗液。 The binder resin is an epoxy resin, silicone resin, phenol resin, urea resin, melamine resin, polyurethane resin, polyethylene resin, polypropylene resin, polystyrene resin, polyester resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, polyamide resin 4. The coating liquid according to claim 1, comprising at least one selected from the group consisting of a polyimide resin, a cellulose resin, and a polyvinyl resin.
- 比重が0.8以下である、請求項1~4のいずれか一項に記載の塗液。 The coating liquid according to any one of claims 1 to 4, wherein the specific gravity is 0.8 or less.
- エアロゲル粒子及びバインダ樹脂を含み、前記エアロゲル粒子の含有量が80質量%以上であり、密度が0.4g/cm3以下である、塗膜。 A coating film containing airgel particles and a binder resin, wherein the content of the airgel particles is 80% by mass or more and the density is 0.4 g / cm 3 or less.
- 前記バインダ樹脂が、エポキシ樹脂、シリコーン樹脂、フェノール樹脂、尿素樹脂、メラミン樹脂、ポリウレタン樹脂、ポリエチレン樹脂、ポリプロピレン樹脂、ポリスチレン樹脂、ポリエステル樹脂、アクリル樹脂、ポリ塩化ビニル樹脂、ポリ酢酸ビニル樹脂、ポリアミド樹脂、ポリイミド樹脂、セルロース系樹脂、及びポリビニル系樹脂からなる群より選択される少なくとも一種を含む、請求項6に記載の塗膜。
The binder resin is an epoxy resin, silicone resin, phenol resin, urea resin, melamine resin, polyurethane resin, polyethylene resin, polypropylene resin, polystyrene resin, polyester resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, polyamide resin The coating film according to claim 6, comprising at least one selected from the group consisting of a polyimide resin, a cellulose resin, and a polyvinyl resin.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2020529875A JP7230914B2 (en) | 2018-07-10 | 2018-07-10 | Coating liquid and coating film |
PCT/JP2018/026010 WO2020012553A1 (en) | 2018-07-10 | 2018-07-10 | Coating liquid and coating film |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/JP2018/026010 WO2020012553A1 (en) | 2018-07-10 | 2018-07-10 | Coating liquid and coating film |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2020012553A1 true WO2020012553A1 (en) | 2020-01-16 |
Family
ID=69141510
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2018/026010 WO2020012553A1 (en) | 2018-07-10 | 2018-07-10 | Coating liquid and coating film |
Country Status (2)
Country | Link |
---|---|
JP (1) | JP7230914B2 (en) |
WO (1) | WO2020012553A1 (en) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPWO2020012554A1 (en) * | 2018-07-10 | 2021-07-08 | 昭和電工マテリアルズ株式会社 | Coating liquid manufacturing method, coating liquid and coating film |
WO2021153755A1 (en) * | 2020-01-31 | 2021-08-05 | 昭和電工マテリアルズ株式会社 | Manufacturing method of heat insulating material |
WO2021152850A1 (en) * | 2020-01-31 | 2021-08-05 | 昭和電工マテリアルズ株式会社 | Method for producing coating fluid and method for producing heat insulator |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10508049A (en) * | 1994-10-20 | 1998-08-04 | ヘキスト・アクチェンゲゼルシャフト | Compositions comprising airgel, methods for their preparation and their use |
JPH11513431A (en) * | 1995-10-11 | 1999-11-16 | ヘキスト、リサーチ、アンド、テクノロジー、ドイッチェラント、ゲゼルシャフト、ミット、ベシュレンクテル、ハフツング、ウント、コンパニー、コマンディート、ゲゼルシャフト | Airgel coated film |
JP2004534108A (en) * | 2001-03-15 | 2004-11-11 | キャボット コーポレイション | Matte thixotrope paint formulation |
JP2005525454A (en) * | 2002-05-15 | 2005-08-25 | キャボット コーポレイション | Composition of airgel and hollow particle binder, insulating composite material, and production method thereof |
JP2006504543A (en) * | 2002-01-29 | 2006-02-09 | キャボット コーポレイション | Heat resistant aerosol insulating composite material and method for producing the same, aerosol binder composition and method for producing the same |
JP2006515556A (en) * | 2002-12-18 | 2006-06-01 | デグサ アクチエンゲゼルシャフト | Surface-modified airgel structured silica |
JP2007514810A (en) * | 2003-11-12 | 2007-06-07 | バーチル,ジー.スチュアート,ジュニア | Composition for thermal insulation layer |
JP2017031386A (en) * | 2015-07-30 | 2017-02-09 | 現代自動車株式会社Hyundai Motor Company | Thermal insulation coating composition and thermal insulation coating layer |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR102613368B1 (en) * | 2018-07-10 | 2023-12-13 | 가부시끼가이샤 레조낙 | Manufacturing method of coating solution, coating solution and coating film |
-
2018
- 2018-07-10 JP JP2020529875A patent/JP7230914B2/en active Active
- 2018-07-10 WO PCT/JP2018/026010 patent/WO2020012553A1/en active Application Filing
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10508049A (en) * | 1994-10-20 | 1998-08-04 | ヘキスト・アクチェンゲゼルシャフト | Compositions comprising airgel, methods for their preparation and their use |
JPH11513431A (en) * | 1995-10-11 | 1999-11-16 | ヘキスト、リサーチ、アンド、テクノロジー、ドイッチェラント、ゲゼルシャフト、ミット、ベシュレンクテル、ハフツング、ウント、コンパニー、コマンディート、ゲゼルシャフト | Airgel coated film |
JP2004534108A (en) * | 2001-03-15 | 2004-11-11 | キャボット コーポレイション | Matte thixotrope paint formulation |
JP2006504543A (en) * | 2002-01-29 | 2006-02-09 | キャボット コーポレイション | Heat resistant aerosol insulating composite material and method for producing the same, aerosol binder composition and method for producing the same |
JP2005525454A (en) * | 2002-05-15 | 2005-08-25 | キャボット コーポレイション | Composition of airgel and hollow particle binder, insulating composite material, and production method thereof |
JP2006515556A (en) * | 2002-12-18 | 2006-06-01 | デグサ アクチエンゲゼルシャフト | Surface-modified airgel structured silica |
JP2007514810A (en) * | 2003-11-12 | 2007-06-07 | バーチル,ジー.スチュアート,ジュニア | Composition for thermal insulation layer |
JP2017031386A (en) * | 2015-07-30 | 2017-02-09 | 現代自動車株式会社Hyundai Motor Company | Thermal insulation coating composition and thermal insulation coating layer |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPWO2020012554A1 (en) * | 2018-07-10 | 2021-07-08 | 昭和電工マテリアルズ株式会社 | Coating liquid manufacturing method, coating liquid and coating film |
JP7259857B2 (en) | 2018-07-10 | 2023-04-18 | 株式会社レゾナック | Coating liquid manufacturing method, coating liquid and coating film |
WO2021153755A1 (en) * | 2020-01-31 | 2021-08-05 | 昭和電工マテリアルズ株式会社 | Manufacturing method of heat insulating material |
WO2021152850A1 (en) * | 2020-01-31 | 2021-08-05 | 昭和電工マテリアルズ株式会社 | Method for producing coating fluid and method for producing heat insulator |
WO2021152853A1 (en) * | 2020-01-31 | 2021-08-05 | 昭和電工マテリアルズ株式会社 | Method for producing heat insulator |
WO2021153764A1 (en) * | 2020-01-31 | 2021-08-05 | 昭和電工マテリアルズ株式会社 | Manufacturing method for coating liquid and manufacturing method for insulating material |
CN115052940A (en) * | 2020-01-31 | 2022-09-13 | 昭和电工材料株式会社 | Method for manufacturing heat insulating material |
CN115052940B (en) * | 2020-01-31 | 2024-05-24 | 株式会社力森诺科 | Method for producing heat insulating material |
Also Published As
Publication number | Publication date |
---|---|
JPWO2020012553A1 (en) | 2021-07-08 |
JP7230914B2 (en) | 2023-03-01 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
JP7196854B2 (en) | Coating liquid, method for producing coating film, and coating film | |
JP7196852B2 (en) | Coating liquid, method for producing coating film, and coating film | |
TWI829911B (en) | Coating fluids, composite materials and coating films | |
JPWO2019069494A1 (en) | Coating liquid, coating film manufacturing method and coating film | |
JP7230914B2 (en) | Coating liquid and coating film | |
JP7259857B2 (en) | Coating liquid manufacturing method, coating liquid and coating film | |
JP7294409B2 (en) | Composites, sheets and insulation | |
WO2019202635A1 (en) | Method for suppressing corrosion under heat-insulating material, and paste for suppressing corrosion under heat-insulating material | |
WO2021153764A1 (en) | Manufacturing method for coating liquid and manufacturing method for insulating material | |
JP7302654B2 (en) | Coating fluids, composites and coatings | |
JP7196853B2 (en) | Coating liquid, method for producing coating film, and coating film | |
JP7160106B2 (en) | Airgel particles, dispersions and coatings | |
JP7107321B2 (en) | Dispersions and airgel particles | |
JP2022059803A (en) | Method for producing coating liquid and method for manufacturing heat insulation material |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
121 | Ep: the epo has been informed by wipo that ep was designated in this application |
Ref document number: 18925915 Country of ref document: EP Kind code of ref document: A1 |
|
ENP | Entry into the national phase |
Ref document number: 2020529875 Country of ref document: JP Kind code of ref document: A |
|
NENP | Non-entry into the national phase |
Ref country code: DE |
|
122 | Ep: pct application non-entry in european phase |
Ref document number: 18925915 Country of ref document: EP Kind code of ref document: A1 |