JP2020015773A - Polysiloxane gel, method for producing the same, heat insulation material and laminated glass - Google Patents

Abstract

To provide a polysiloxane gel having high bending fracture stress; a method for producing a polysiloxane gel having high bending fracture stress; a heat insulation material that has high heat insulation performance and resists cracking; and a laminated glass that has high heat insulation performance and prevents cracking in a transparent heat insulation layer.SOLUTION: A polysiloxane gel contains a three-dimensional network containing a 6 membered ring-containing skeleton having at least one 6 membered ring selected from the group consisting of a ring structure represented by formula (a), a ring structure represented by formula (b) and a ring structure represented by formula (c), and a polysiloxane skeleton, where, * is a bond.SELECTED DRAWING: None

Description

  The present invention relates to a polysiloxane gel, a method for producing the same, a heat insulating material, and a laminated glass.

  BACKGROUND ART Transparent heat insulating materials are expected to be used as heat insulating materials in automotive window glasses and building window glasses for the purpose of improving the cooling and heating efficiency of the interior of automobiles and buildings.

For example, the following materials have been proposed as transparent heat insulating materials.
-An alkylsiloxane aerogel having a three-dimensional network structure formed from a through-hole continuous in a three-dimensional network and a skeleton continuous in a three-dimensional network made of alkylsiloxane (Patent Document 1).

International Publication No. 2007/010949

  However, the alkylsiloxane airgel of Patent Document 1 is brittle and cannot be bent. Therefore, the alkylsiloxane airgel of Patent Document 1 is easily broken when a force in the bending direction is applied, and is not easy to use.

  The present invention provides a polysiloxane gel having a high flexural fracture stress; a method for producing a polysiloxane gel having a high flexural fracture stress; a heat insulating material having a high heat insulating property and hardly causing cracks; and a high heat insulating property and a transparent heat insulating layer. Provide a laminated glass that is less likely to break.

ただし、＊は結合手である。
本発明のポリシロキサンゲルの製造方法は、下式（ａ）で表される環構造、下式（ｂ）で表される環構造および下式（ｃ）で表される環構造からなる群から選ばれる少なくとも１種の６員環を有する６員環含有骨格と、ポリシロキサン骨格とを有する三次元網目を含むポリシロキサンゲルを製造する方法であり；下式（ａ）で表される環構造、下式（ｂ）で表される環構造および下式（ｃ）で表される環構造からなる群から選ばれる少なくとも１種の６員環を有する６員環含有骨格と加水分解性シリル基とを有する６員環含有シラン化合物と、溶媒とを含む混合物をゲル化させて湿潤ゲルを得る。

ただし、＊は結合手である。
本発明の断熱材は、本発明のポリシロキサンゲルを備える。
本発明の合わせガラスは、第１のガラス板と、第２のガラス板と、前記第１のガラス板と前記第２のガラス板との間に存在する透明断熱層とを備え、前記透明断熱層が、本発明のポリシロキサンゲルである。 The polysiloxane gel of the present invention has at least one selected from the group consisting of a ring structure represented by the following formula (a), a ring structure represented by the following formula (b), and a ring structure represented by the following formula (c). It includes a three-dimensional network having a six-membered ring-containing skeleton having one type of six-membered ring and a polysiloxane skeleton.

Here, * is a bond.
The method for producing a polysiloxane gel of the present invention comprises a ring structure represented by the following formula (a), a ring structure represented by the following formula (b), and a ring structure represented by the following formula (c). A method for producing a polysiloxane gel including a three-dimensional network having a 6-membered ring-containing skeleton having at least one selected 6-membered ring and a polysiloxane skeleton; a ring structure represented by the following formula (a): A 6-membered ring-containing skeleton having at least one 6-membered ring selected from the group consisting of a ring structure represented by the following formula (b) and a ring structure represented by the following formula (c), and a hydrolyzable silyl group A mixture containing the 6-membered ring-containing silane compound having the formula (I) and a solvent is gelled to obtain a wet gel.

Here, * is a bond.
The heat insulating material of the present invention includes the polysiloxane gel of the present invention.
The laminated glass of the present invention includes a first glass plate, a second glass plate, and a transparent heat insulating layer existing between the first glass plate and the second glass plate. The layer is the polysiloxane gel of the present invention.

The polysiloxane gel of the present invention has high bending fracture stress.
According to the method for producing a polysiloxane gel of the present invention, a polysiloxane gel having a high bending fracture stress can be produced.
The heat insulating material of the present invention has high heat insulating properties and is less likely to crack.
The laminated glass of the present invention has a high heat insulating property and hardly causes cracks in the transparent heat insulating layer.

It is sectional drawing which shows an example of the laminated glass of this invention.

The following definitions of terms apply throughout the present specification and claims.
The “polysiloxane gel” means a gel containing a three-dimensional network having a polysiloxane skeleton in which siloxane bonds (Si—O—Si) are continuous. The polysiloxane gel includes a wet gel containing a swelling agent (solvent) and a xerogel containing no swelling agent.
"Wet gel" means a gel in which a three-dimensional network has been swollen by a swelling agent. It includes hydrogels in which the swelling agent is water, alcogels in which the swelling agent is alcohol, and organogels in which the swelling agent is an organic solvent.
"Xerogel" is defined by the International Union of Pure and Applied Chemistry (IUPAC) Inorganic Chemistry Subcommittee and Polymers Subcommittee, Polymer Terminology Subcommittee "Definition of terms related to structure and process of sol, gel, mesh, and inorganic-organic composite materials ( According to IUPAC Recommendation 2007), it means "a gel consisting of an open network formed by removing a swelling agent from a gel." There is also a classification method in which the swelling agent removed by supercritical drying is aerogel, the one in which the swelling agent is removed by ordinary evaporation drying is xerogel, and the one in which the swelling agent is removed by freeze drying is cryogel, but this specification and In the claims, these are collectively called xerogels.
“Transparent” means that light can be transmitted.
"Bending fracture stress" is a value measured in accordance with JIS K 7171: 2008 "Plastic-Determination of bending properties" (ISO 178: 2001).
The “transmittance” is a value measured in accordance with JIS R 3106: 1998 “Test method for transmittance, reflectance, emissivity, and solar heat gain of plate glass” (ISO 9050: 1990).
“Thermal conductivity” is based on JIS A 1412-2: 1999 “Method for measuring thermal resistance and thermal conductivity of thermal insulation material-Part 2: Heat flow meter method (HFM method)” (ISO 8301: 1991). This is the value measured.
The “average pore diameter” is a value obtained by measuring the nitrogen adsorption method using a pore distribution measuring apparatus, and the cumulative pore volume plot of the BJH (Barrett-Joyner-Halenda) method adsorption becomes 50% higher. It is the value of the pore diameter called.
The “average porosity” is a value determined by the following equation from the volume of the xerogel before pressing and the volume of the xerogel after pressing under the conditions of temperature: 100 ° C., pressure: 50 MPa, and time: 10 minutes.
Average porosity = {1- (volume of xerogel after pressing / volume of xerogel before pressing)} × 100
The “compression modulus” is a value measured in accordance with JIS K 7181: 2011 “Plastic-Determination of compression characteristics” (ISO 604: 2002).

<Polysiloxane gel>
The polysiloxane gel of the present invention includes a three-dimensional network having a specific six-membered ring-containing skeleton and a polysiloxane skeleton.
The polysiloxane gel of the present invention may be a wet gel containing a solvent or a xerogel containing no solvent.

(6-membered ring-containing skeleton)
The 6-membered ring-containing skeleton has a specific 6-membered ring.
The 6-membered ring-containing skeleton preferably further has a linking group interposed between the 6-membered ring and the polysiloxane skeleton.

  The 6-membered ring-containing skeleton preferably has a plurality of bonds, and at least two of the bonds are directly or indirectly bonded to the polysiloxane skeleton. Is more preferably bonded directly or indirectly to the polysiloxane skeleton. When the two bonds of the 6-membered ring-containing skeleton are directly or indirectly bonded to the polysiloxane skeleton, the 6-membered ring-containing skeleton is incorporated in the middle of the path of the three-dimensional network, and the bending fracture stress of the polysiloxane gel is reduced. It will be even higher. When the three bonds of the 6-membered ring-containing skeleton are directly or indirectly bonded to the polysiloxane skeleton, the 6-membered ring-containing skeleton becomes a branch point of a three-dimensional network, and the bending fracture stress of the polysiloxane gel is further increased. .

(6-member ring)
The 6-membered ring in the 6-membered ring-containing skeleton includes a ring structure represented by the following formula (a) (hereinafter, also referred to as a ring structure (a)) and a ring structure represented by the following formula (b) (hereinafter, a ring structure) It is at least one selected from the group consisting of a structure (b) and a ring structure represented by the following formula (c) (hereinafter also referred to as a ring structure (c)).

Here, * is a bond. In the ring structure (a) and the ring structure (b), two or three of the three bonds are preferably directly or indirectly bonded to the polysiloxane skeleton, and three are directly or indirectly bonded to the polysiloxane skeleton. More preferably. In the ring structure (c), two to four of the six bonds are preferably directly or indirectly bonded to the polysiloxane skeleton, and three or four are directly or indirectly bonded to the polysiloxane skeleton. Is more preferred. Among the bonds in each ring structure, the other bonds that are not directly or indirectly bonded to the polysiloxane skeleton are bonded to, for example, other groups described below.
The 6-membered ring-containing skeleton may have a plurality of types of 6-membered rings.
As the 6-membered ring, the ring structure (a) is preferable from the viewpoint of availability of a 6-membered ring-containing silane compound as a raw material.

(Linking group)
The linking group in the 6-membered ring-containing skeleton is, for example, a group formed when a hydrolyzable silyl group is introduced into a 6-membered ring in the production of a 6-membered ring-containing silane compound described below.
When the six-membered ring-containing skeleton has a linking group, the ratio of the six-membered ring-containing skeleton, which is an organic skeleton in the three-dimensional network, increases, and the bending fracture stress of the polysiloxane gel further increases.

The linking group is a divalent or higher valent group having at least one group selected from the group consisting of an alkylene group, an oxyalkylene group, a polyether chain, and an arylene group. As the linking group, a divalent group having an alkylene group or a polyether chain or an oxyalkylene group is preferable from the viewpoint of availability of a 6-membered ring-containing silane compound as a raw material, and a divalent group having an alkylene group is preferable. Groups are more preferred.
1-18 are preferable, as for carbon number of an alkylene group, 2-8 are more preferable, and 3-6 are more preferable. When the number of carbon atoms of the alkylene group is equal to or more than the lower limit of the above range, the bending rupture stress of the polysiloxane gel is further increased. When the number of carbon atoms in the alkylene group is equal to or less than the upper limit of the above range, shrinkage during gel drying can be reduced, and a decrease in porosity can be prevented.

  The linking group may further have a bond such as -O-, -NH-, -C (O) O-, -NHC (O)-, at the terminal or in the middle.

(Other groups)
The 6-membered ring-containing skeleton may further have a hydrogen atom, a fluorine atom, a chlorine atom, and a monovalent organic group whose terminal is a free end, which is bonded to the 6-membered ring and not bonded to the polysiloxane skeleton.

(Polysiloxane skeleton)
The polysiloxane skeleton is a skeleton in which siloxane bonds (Si-O-Si) are continuous.
The polysiloxane skeleton may have a pendant group bonded to Si. Examples of the pendant group include a monovalent organic group, for example, an alkyl group, a cycloalkyl group, an alkenyl group, an aryl group, and those in which a hydrogen atom thereof is substituted by a halogen atom.

(Polysiloxane wet gel)
The polysiloxane wet gel contains a three-dimensional network and a solvent.
Examples of the solvent include water, alcohols (methanol, ethanol, isopropyl alcohol, tert-butyl alcohol, etc.), aprotic polar organic solvents (N, N-dimethylformamide, dimethyl sulfoxide, N, N-dimethylacetamide, etc.), hydrocarbons (N-hexane, heptane, etc.), fluorinated solvents (2H, 3H-decafluoropentane, 1,1,2,2,3,3,4-heptafluorocyclopentane), and mixtures thereof.

(Polysiloxane xerogel)
The polysiloxane xerogel is obtained by replacing the solvent contained in the wet gel with a gas, and comprises a three-dimensional network. The polysiloxane xerogel has a three-dimensional fine porous structure in which continuous pores exist between the three-dimensional network skeleton.

(Bending fracture stress)
The bending rupture stress of the polysiloxane gel is preferably at least 0.3 MPa, more preferably at least 0.5 MPa, further preferably at least 1 MPa, particularly preferably at least 3 MPa, most preferably at least 6 MPa. When the bending rupture stress of the polysiloxane gel is 0.3 MPa or more, the polysiloxane gel does not become brittle and the usability is good. The bending rupture stress of the polysiloxane gel is preferably 50 MPa or less, more preferably 30 MPa or less, further preferably 20 MPa or less, particularly preferably 15 MPa or less, and most preferably 10 MPa or less. When the bending fracture stress of the polysiloxane gel is 50 MPa or less, continuous pores in the polysiloxane xerogel are sufficiently formed, and the heat insulation property of the polysiloxane xerogel is excellent.

(Transmissivity)
The 1 mm thickness-converted value of the transmittance of the polysiloxane gel for light having a wavelength of 500 nm is preferably 50% or more, more preferably 70% or more, and even more preferably 80% or more. When the transmittance of the polysiloxane gel is equal to or more than the lower limit of the above range, the transparency of the polysiloxane gel is excellent. The 1 mm thickness conversion value of the transmittance of the polysiloxane gel for light having a wavelength of 500 nm is preferably as high as possible, and the upper limit is 100%.

(Thermal conductivity)
The thermal conductivity of the polysiloxane gel is preferably at least 5 mW / (m · K), more preferably at least 10 mW / (m · K), even more preferably at least 12 mW / (m · K). When the thermal conductivity of the polysiloxane gel is 5 mW / (m · K) or more, a three-dimensional network is densely formed, and the bending fracture stress of the polysiloxane gel increases. The thermal conductivity of the polysiloxane gel is preferably 40 mW / (m · K) or less, more preferably 25 mW / (m · K) or less, and even more preferably 20 mW / (m · K) or less. When the thermal conductivity of the polysiloxane gel is 40 mW / (m · K) or less, the heat insulation of the polysiloxane gel is excellent.

(Pore size and porosity)
Compatibility of the transparency and the heat insulating property of the polysiloxane gel can be achieved by adjusting the pore diameter and porosity of continuous pores in the polysiloxane xerogel.
The average pore diameter of the continuous pores in the polysiloxane xerogel is preferably 10 nm or more, more preferably 30 nm or more, still more preferably 40 nm or more, and particularly preferably 50 nm or more. When the average pore diameter of the continuous pores is 10 nm or more, the heat insulation property of the polysiloxane xerogel is excellent. The average pore diameter of continuous pores in the polysiloxane xerogel is preferably 150 nm or less, more preferably 100 nm or less, further preferably 70 nm or less, and particularly preferably 60 nm or less. When the average pore diameter of the continuous pores is 150 nm or less, the heat insulation property and transparency of the polysiloxane xerogel are excellent.

  The average porosity of the polysiloxane xerogel is preferably at least 50%, more preferably at least 70%, further preferably at least 80%, particularly preferably at least 90%. When the average porosity of the polysiloxane xerogel is 50% or more, the heat insulation of the polysiloxane xerogel is excellent. The average porosity of the polysiloxane xerogel is preferably 97% or less, more preferably 95% or less, and even more preferably 93% or less. When the average porosity of the polysiloxane xerogel is 97% or less, the bending rupture stress of the polysiloxane xerogel increases.

(Mechanism of action)
In the polysiloxane gel of the present invention described above, the bending fracture stress is increased by the combination of the specific 6-membered ring-containing skeleton that is an organic skeleton and the polysiloxane skeleton that is an inorganic skeleton.

<Method for producing polysiloxane gel>
The method for producing a polysiloxane gel of the present invention is a method comprising the following steps (i) to (iii).
Step (i): a step of gelling a mixture containing a specific 6-membered ring-containing silane compound and a solvent to obtain a wet gel.
Step (ii): a step of replacing the solvent of the wet gel as necessary.
Step (iii): a step of removing the solvent from the wet gel, if necessary, to obtain a xerogel.

(6-membered ring-containing silane compound)
The 6-membered ring-containing silane compound has a specific 6-membered ring-containing skeleton and a hydrolyzable silyl group.
The six-membered ring-containing skeleton is the same as the six-membered ring-containing skeleton in the three-dimensional network described above, and the preferred embodiment is also the same.

  The hydrolyzable silyl group becomes a silanol group (Si—OH) by a hydrolysis reaction during gelation, and further reacts between molecules to form a Si—O—Si bond to form a polysiloxane skeleton.

Examples of the hydrolyzable silyl group include a group represented by the following formula (x).
—SiR _n L _3-n (x)
Here, R is a hydrogen atom or a monovalent hydrocarbon group, L is a hydrolyzable group, and n is an integer of 0 to 2.

Examples of R include an alkyl group, a cycloalkyl group, an alkenyl group, and an aryl group, and an alkyl group is preferable.
Examples of L include an alkoxy group, a halogen atom, an acyl group, an isocyanate group, and the like. From the viewpoint of easy production of a 6-membered ring-containing silane compound, a methoxy group or an ethoxy group is preferable, and a point of high reactivity. Therefore, a methoxy group is more preferable.
n is preferably 0 or 1, and more preferably 0, in that a three-dimensional network is easily formed.

  The 6-membered ring-containing silane compound preferably has at least two hydrolyzable silyl groups, more preferably at least three hydrolyzable silyl groups. When the 6-membered ring-containing silane compound has at least two hydrolyzable silyl groups, the 6-membered ring-containing skeleton is incorporated in the middle of the path of the three-dimensional network, and the bending fracture stress of the polysiloxane gel is further increased. When the six-membered ring-containing silane compound has at least three hydrolyzable silyl groups, the six-membered ring-containing skeleton serves as a branch point of a three-dimensional network, and the bending stress of the polysiloxane gel further increases.

  Examples of the 6-membered ring-containing silane compound include a compound having a ring structure (a) and a hydrolyzable silyl group (hereinafter also referred to as compound (α)), a ring structure (b) and a hydrolyzable silyl group. (Hereinafter, also referred to as compound (β)), a compound having a ring structure (c) and a hydrolyzable silyl group (hereinafter, also referred to as compound (γ)), and the like.

  Preferred examples of the compound (α) include a compound represented by the following formula (α1). Preferred examples of the compound (β) include a compound represented by the following formula (β1). Preferred examples of the compound (γ) include a compound represented by the following formula (γ1).

However, Q ¹ , Q ² and Q ³ are each a linking group. p is an integer of 1 to 3, preferably 2 or 3. In the ring structure (c) of the formula (γ1), the above-mentioned other groups (hydrogen atom, fluorine atom, chlorine atom, monovalent organic group) are bonded to carbon atoms other than the carbon atom to which Q ³ is bonded. A plurality of Q ¹ may be the same group, or a part or all may be different groups. The same applies to Q ² , Q ³ and SiR _n L _3-n .

Q ¹ , Q ² and Q ³ each include a divalent or higher valent group having at least one group selected from the group consisting of an alkylene group, an oxyalkylene group, a polyether chain and an arylene group. As Q ¹ , Q ² and Q ³ , — (CH ₂ ) _m — and —O (CH ₂ ) _m — (where m is an integer of 1 to 18) are preferable.

  As the compound (α), a compound (α1-1) represented by the following formula is preferable from the viewpoint of availability. Compound (α1-1) can be obtained from Tokyo Chemical Industry Co., Ltd. or the like.

The 6-membered ring-containing silane compound includes, for example, a compound having a specific 6-membered ring and a carbon-carbon unsaturated bond (vinyl group, allyl group, etc.) (triallyl isocyanurate, divinylbenzene, trivinylbenzene, etc.) and hydrosilyl It can be produced by subjecting a compound having a group (HSiR _n L _3-n ) to a hydrosilylation reaction by the method described in JP-A-2012-121852, JP-A-2012-121853, and the like.

(Step (i))
Examples of the solvent used in the step (i) include the solvent in the above-mentioned polysiloxane wet gel, which has good solubility of the compound (α) and affinity with the gel, forms a fine three-dimensional network structure, and is transparent. An aprotic polar organic solvent or alcohol is preferred because a gel having excellent properties is easily obtained. Further, it preferably contains water for hydrolyzing the hydrolyzable silyl group.

The mixture may further include another silane compound having a hydrolyzable silyl group. When the mixture further contains another silane compound, a skeleton derived from the other silane compound is introduced into the three-dimensional network, and the characteristics of the skeleton can be imparted to the polysiloxane gel.
Other silane compounds include alkoxysilanes; silyl group-containing polymers having a hydrolyzable silyl group and an organic polymer skeleton having at least one chain selected from the group consisting of polyether chains, polyester chains and polycarbonate chains. No.

  Examples of the alkoxysilane include tetraalkoxysilanes (tetramethoxysilane, tetraethoxysilane, etc.), monoalkyl trialkoxysilanes (methyltrimethoxysilane, methyltriethoxysilane, etc.), and dialkyldialkoxysilanes (dimethyldimethoxysilane, dimethyldiethoxysilane) Etc.), trimethoxyphenylsilane, compounds having alkoxysilyl groups at both ends of an alkylene group (1,6-bis (trimethoxysilyl) hexane, 1,2-bis (trimethoxysilyl) ethane, etc.), perfluoropolyether Alkoxysilane having a perfluoroalkyl group (e.g., perfluoropolyether triethoxysilane), alkoxysilane having a perfluoroalkyl group (e.g., perfluoroethyltriethoxysilane), pentafluorophenylethoxy Dimethylsilane, trimethoxy (3,3,3-trifluoropropyl) silane, alkoxysilane having a vinyl group (vinyltrimethoxysilane, vinyltriethoxysilane, etc.), and alkoxysilane having an epoxy group (2- (3,4- Epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, etc.), alkoxysilane having an acryloyloxy group (3 -Acryloyloxypropyltrimethoxysilane and the like).

Examples of the silyl group-containing polymer include JP-A-6-340798, WO 2010/013653, WO 2010/041667, JP-A-2010-111962, JP-A-2010-24070, and JP-A-547284. And the like.
Commercially available silyl group-containing polymers include Exester (a modified polyether polymer in which a hydrolyzable silyl group is introduced into the end of a polyether polyol) manufactured by Asahi Glass Co., Ltd.

  The proportion of the 6-membered ring-containing silane compound in the total (100% by mass) of the 6-membered ring-containing silane compound and the other silane compounds in the mixture is preferably 5 to 100% by mass, more preferably 20 to 100% by mass. Preferably, it is more preferably 50 to 100% by mass. When the proportion of the 6-membered ring-containing silane compound is equal to or more than the lower limit of the above range, the bending rupture stress of the polysiloxane gel is further increased.

  The gelation of the mixture is performed by hydrolyzing the hydrolyzable silyl groups of the 6-membered ring-containing silane compound or other silane compounds in the presence of a base catalyst or an acid catalyst to generate silanol groups (Si-OH). Is reacted between molecules to form a Si—O—Si bond. For example, when the 6-membered ring-containing silane compound is a compound represented by the formula (α1-1), three Si—O—Si bonds are formed in each of three trimethoxysilyl groups as shown in the following formula. , A three-dimensional network having a 6-membered ring-containing skeleton and a polysiloxane skeleton is formed.

Examples of the base catalyst include an amine (such as tetramethylammonium hydroxide), urea, ammonia, sodium hydroxide, and potassium hydroxide. Examples of the acid catalyst include inorganic acids (such as nitric acid, sulfuric acid, and hydrochloric acid) and organic acids (such as formic acid, oxalic acid, acetic acid, monochloroacetic acid, dichloroacetic acid, and trichloroacetic acid).
The mixture may further include a surfactant such as hexadecyltrimethylammonium bromide and hexadecyltrimethylammonium chloride.

(Step (ii))
The solvent replacement is performed by immersing the wet gel in a solvent.
Examples of the solvent used in the step (ii) include the solvents in the above-described polysiloxane wet gel. When supercritical drying is performed in the step (iii), the solvent is preferably replaced with an alcohol such as methanol, ethanol, or isopropyl alcohol. When evaporating and drying in the step (iii), it is preferable to replace the solvent with a hydrocarbon solvent such as hexane or heptane having a low surface tension or a fluorinated solvent (2H, 3H-decafluoropentane). When drying, it is preferable to substitute t-butanol or a fluorinated solvent (1,1,2,2,3,3,4-heptafluorocyclopentane) or the like.

(Step (iii))
As a method for drying a wet gel, a normal pressure drying method, a freeze drying method (freeze drying), a subcritical drying method, a supercritical drying method, and the like are known.

The evaporative drying is performed, for example, by evaporating the solvent from the wet gel under conditions of a temperature of 30 to 100 ° C. and normal pressure.
Freeze-drying is performed by, for example, freezing the wet gel at a temperature of -30 to 0 ° C, and then vacuum-drying at a temperature of -30 to 100 ° C.
The supercritical drying is performed by, for example, bringing supercritical carbon dioxide into contact with the wet gel under the conditions of a temperature of 35 to 100 ° C and a pressure of 7.4 to 30 MPa.

(Mechanism of action)
In the method for producing a polysiloxane gel of the present invention described above, a method of gelling a mixture containing a solvent containing a 6-membered ring-containing silane compound having a specific 6-membered ring-containing skeleton and a hydrolyzable silyl group is used. Therefore, it is possible to produce a polysiloxane gel having a high bending fracture stress, having a specific 6-membered ring-containing skeleton that is an organic skeleton and a polysiloxane skeleton that is an inorganic skeleton.

<Insulation material>
The heat insulating material of the present invention includes the polysiloxane gel of the present invention. As the polysiloxane gel, a polysiloxane xerogel is preferable because of its excellent heat insulating property.
The heat insulating material of the present invention may be in the form of a sheet, a plate, or a molded article having an arbitrary shape.

The heat insulating material of the present invention may be composed only of a polysiloxane gel; may be a laminate composed of a layer composed of a polysiloxane gel and another layer; and a sheet-shaped or plate-shaped polysiloxane. A frame-shaped frame supporting the gel may be provided on the periphery.
Other layers include an adhesive layer, a glass plate, a plastic plate, a plastic film, a penetration resistant film, and the like.

  The heat insulating material of the present invention described above is provided with the polysiloxane gel having heat insulating properties, and therefore has high heat insulating properties. In addition, since the polysiloxane gel of the present invention having a high bending fracture stress is provided, cracks are less likely to occur in the polysiloxane gel.

<Laminated glass>
The laminated glass of the present invention is a transparent heat insulating layer comprising the first glass plate, the second glass plate, and the polysiloxane gel of the present invention, which is present between the first glass plate and the second glass plate. And
The laminated glass of the present invention may further include a transparent adhesive layer between the first glass plate or the second glass plate and the transparent heat insulating layer.

FIG. 1 is a sectional view showing an example of the laminated glass of the present invention.
The laminated glass 1 includes a first glass plate 10; a second glass plate 12; a transparent heat insulating layer 14 disposed between the first glass plate 10 and the second glass plate 12; A first transparent adhesive layer 16 for bonding the glass plate 10 and the transparent heat insulating layer 14; and a second transparent adhesive layer 18 for bonding the second glass plate 12 and the transparent heat insulating layer 14.

(Glass plate)
The material of the first glass plate and the second glass plate (hereinafter, also collectively referred to as a glass plate) may be an inorganic glass or an organic glass, and has weather resistance, rigidity, and solvent resistance. In view of the above, inorganic glass is preferable. The materials of the first glass plate and the second glass plate may be the same or different.
Examples of the inorganic glass include soda lime glass, borosilicate glass, alkali-free glass, and quartz glass, and soda lime glass is preferable.
Examples of the organic glass include polycarbonate and acrylic resin.

The glass plate may be a colorless transparent glass plate or a colored transparent glass plate, and is preferably a heat ray absorbing glass plate (blue glass plate or green glass plate) containing a large amount of iron.
As the glass plate, a tempered glass plate may be used to enhance safety. As the tempered glass sheet, a tempered glass sheet obtained by an air-cooling tempering method or a chemical tempering method can be used.

  The shape of the glass plate may be curved or flat. Since window glass for automobiles is often curved, when the laminated glass of the present invention is used as window glass for automobiles, the shape of the glass plate is often curved.

  The thickness of the glass plate is preferably from 0.1 to 6 mm, more preferably from 1 to 3 mm. The thickness of the first glass plate and the second glass plate may be the same or different. In addition, the thickness of the glass plate in the present invention is a geometric thickness. Hereinafter, the same applies to the thickness of each layer of the laminated glass of the present invention other than the glass plate.

(Transparent adhesive layer)
The material of the first transparent adhesive layer and the second transparent adhesive layer (hereinafter, also collectively referred to as a transparent adhesive layer) may be a transparent resin capable of bonding the glass plate and the transparent heat insulating layer. Examples of the transparent resin include polyvinyl butyral, an ethylene-vinyl acetate copolymer, and a commercially available optically transparent adhesive (OCA: Optically Clear Adhesive). Polyvinyl butyral and an ethylene-vinyl acetate copolymer are preferable, and In applications requiring penetration resistance, such as window glass, polyvinyl butyral is more preferred. The materials of the first transparent adhesive layer and the second transparent adhesive layer may be the same or different. Further, each transparent adhesive layer may be a laminate of two or more materials of the same type or different types.

The transparent adhesive layer may contain an infrared absorber, an ultraviolet absorber, an antioxidant, a light stabilizer, a coloring agent, and the like within a range that does not impair the effects of the present invention.
The thickness of the transparent adhesive layer is preferably from 0.1 to 3 mm, more preferably from 0.3 to 0.8 mm. The thicknesses of the first transparent adhesive layer and the second transparent adhesive layer may be the same or different.

(Transparent thermal insulation layer)
The transparent heat insulating layer is made of a sheet-like polysiloxane gel of the present invention. As the polysiloxane gel, a polysiloxane xerogel is preferable because of its excellent heat insulating property.
The compression elastic modulus of the transparent heat insulating layer is preferably 1.3 MPa or more, more preferably 4.3 MPa or more, still more preferably 5.0 MPa or more, and particularly preferably 12 MPa or more. When the compression elastic modulus is 1.0 MPa or more, the transparent heat-insulating layer has excellent mechanical strength and can withstand compression when bonded to a glass plate during production of a laminated glass.

  The thickness of the transparent heat insulating layer is preferably 0.2 to 10 mm, more preferably 0.5 to 6 mm, and still more preferably 1 to 3 mm. When the thickness of the transparent heat insulating layer is equal to or more than the lower limit of the above range, the heat insulating property of the laminated glass is further excellent. When the thickness of the transparent heat insulating layer is equal to or less than the upper limit of the above range, the transparency of the laminated glass is further increased.

(Characteristics of laminated glass)
The transmittance of the laminated glass at a wavelength of 500 nm is preferably 50% or more, more preferably 70 to 99%, and even more preferably 80 to 96%. When the transmittance of light having a wavelength of 500 nm is equal to or higher than the lower limit of the above range, the transparency of the laminated glass is increased. It is difficult to manufacture a laminated glass in which the transmittance of light having a wavelength of 500 nm exceeds the upper limit of the above range.

Glass heat penetration rate of combined (U value), since laminated glass for current vehicle is 5.8 W / ^{m 2} K, in terms of fuel efficiency, less preferably 5.0W / ^{m 2} K, 4 0.0 W / m ² K or less is more preferable.

  The thickness of the laminated glass is preferably 2 to 20 mm, more preferably 3 to 10 mm, and still more preferably 4 to 6 mm. When the thickness of the laminated glass is equal to or more than the lower limit of the above range, the heat insulating property of the laminated glass is further excellent, and the mechanical strength is also excellent. When the thickness of the laminated glass is equal to or less than the upper limit of the above range, the laminated glass does not become too heavy and has excellent transparency.

(Method of manufacturing laminated glass)
The laminated glass can be manufactured by a known method. For example, a second glass plate, a transparent resin sheet serving as a second transparent adhesive layer, a sheet-like polysiloxane gel of the present invention serving as a transparent heat insulating layer, a transparent resin sheet serving as a first transparent adhesive layer, a first transparent adhesive sheet, It can be manufactured by stacking glass plates in order, temporarily bonding them, and then finally bonding them by heating and pressing. At this time, the transparent resin sheet serving as the first transparent adhesive layer and the transparent resin sheet serving as the second transparent adhesive layer may be of the same type, or may be composed of two or more sheets of different types. Good.

(Other forms)
The laminated glass of the present invention is a transparent heat insulating layer comprising the first glass plate, the second glass plate, and the polysiloxane gel of the present invention, which is present between the first glass plate and the second glass plate. It is sufficient that the device has the following, and is not limited to the illustrated example.

For example, the laminated glass of the present invention may have a third glass plate or more glass plates as necessary.
The laminated glass of the present invention may have a functional layer other than the transparent heat-insulating layer, such as an infrared absorbing layer and an ultraviolet absorbing layer.

(Mechanism of action)
The laminated glass of the present invention described above has a high heat insulating property because it has a transparent heat insulating layer made of polysiloxane gel. Further, since the transparent heat insulating layer is the polysiloxane gel of the present invention having a high bending fracture stress, the transparent heat insulating layer is less likely to crack.

  Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples.

(Average pore diameter)
The average pore diameter of the continuous pores in the xerogel was determined by measuring the nitrogen adsorption method using a pore distribution measuring device (3Flex-2MP, manufactured by Shimadzu Corporation). , Which is a value of a pore diameter generally called a median diameter.

(Average porosity)
The average porosity of the xerogel was determined from the volume of the xerogel before pressing and the volume of the xerogel after pressing under the conditions of temperature: 100 ° C., pressure: 50 MPa, and time: 10 minutes.
Average porosity = {1- (volume of xerogel after pressing / volume of xerogel before pressing)} × 100

(Bending fracture stress)
The bending fracture stress of the polysiloxane xerogel was measured using a table-top precision universal testing machine (Autograph AGS-5kNX, manufactured by Shimadzu Corporation) in accordance with JIS K 7171: 2008 (ISO 178: 2001).

(Transmissivity)
The light transmittance of the polysiloxane xerogel at a wavelength of 500 nm was measured using a spectrophotometer (SolidSpec-3700DUV, manufactured by Shimadzu Corporation) in accordance with JIS R 3106: 1998 (ISO 9050: 1990).

(Thermal conductivity)
The thermal conductivity of the polysiloxane xerogel was measured using a thermal conductivity measuring device (HC-074 / 630, manufactured by Eiko Seiki Co., Ltd.) in accordance with JIS A 1412-2: 1999 (ISO 8301: 1991).

(Compressive modulus)
The compression elastic modulus of the polysiloxane xerogel was measured using a desktop precision universal testing machine (Shimadzu Corporation, Autograph AGS-5kNX) in accordance with JIS K 7181: 2011 (ISO 604: 2002).

(Example 1)
5 g of compound (α1-1) (manufactured by Tokyo Chemical Industry Co., Ltd., tris [3- (trimethoxysilyl) propyl] isocyanurate) and 30 g of N, N-dimethylformamide (hereinafter, also referred to as DMF), a magnetic stirrer. And stirred for 1 minute at room temperature. To this, 2 g of a 0.75 mol / L aqueous solution of tetramethylammonium hydroxide as a base catalyst and a surfactant was added, and the mixture was stirred at 1500 rpm for 10 seconds to obtain a mixture. The obtained mixture was placed in two polypropylene trays with different liquid thicknesses. The tray was put into a stainless steel airtight container, the lid was closed, and the tray was put in an oven at 60 ° C. in a sealed state to promote gelation. Three days later, the container was taken out of the oven, and the wet gel in the tray was immersed in methanol in another stainless steel closed container. The methanol in the container was replaced with new methanol every 24 hours. The exchange of methanol was repeated four times to obtain a methanol gel. The same solvent replacement was repeated four times, replacing the solvent with hexane, and the solvent of the methanol gel was replaced with hexane to obtain a hexane gel. The hexane gel was placed in an oven at 60 ° C. and dried under normal pressure for 24 hours to obtain polysiloxane xerogels having a thickness of 1 mm and 10 mm.
The transmittance was measured for a polysiloxane xerogel having a thickness of 1 mm, and the average pore diameter, average porosity, bending fracture stress, thermal conductivity, and compression modulus were measured for a polysiloxane xerogel having a thickness of 10 mm. Table 1 shows the results.

(Example 2)
Supercritical drying of carbon dioxide was performed using a methanol gel obtained in the same manner as in Example 1 to obtain a polysiloxane xerogel. Specifically, a high-pressure vessel was filled with methanol, and a methanol gel was placed therein. After forming a closed system with a lid, liquefied carbon dioxide gas was introduced at 20 ° C. at a rate of 10 mL / min, and the pressure was adjusted and maintained at a constant value of 26 MPa with a back pressure valve. After this operation was continued for 24 hours, the temperature of the high-pressure vessel was raised to 50 ° C. while maintaining the pressure at 26 MPa to bring it into a supercritical state. Carbon dioxide was kept flowing at 5 mL / min to maintain 26 MPa. After 3 hours, the supercritical carbon dioxide was purged and returned to normal pressure over 1 hour. The high pressure vessel was opened, the xerogel was taken out, and dried in a vacuum oven at 50 ° C. for 16 hours to obtain polysiloxane xerogels having a thickness of 1 mm and 10 mm. The same measurement as in Example 1 was performed. Table 1 shows the results.

(Example 3)
Polysiloxane xerogels having a thickness of 1 mm and 10 mm were obtained in the same manner as in Example 1 except that dimethyl sulfoxide (hereinafter, also referred to as DMSO) was used instead of DMF. The same measurement as in Example 1 was performed. Table 1 shows the results.

(Example 4)
Instead of using 5 g of the compound (α1-1), a thickness of 1 mm was obtained in the same manner as in Example 1 except that 3 g of the compound (α1-1) and 2 g of methyltrimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) were used. And a 10 mm polysiloxane xerogel was obtained. The same measurement as in Example 1 was performed. Table 2 shows the results.

(Example 5)
Polysiloxane xerogels having a thickness of 1 mm and 10 mm were prepared in the same manner as in Example 1 except that 1 g of the compound (α1-1) and 4 g of methyltrimethoxysilane were used instead of 5 g of the compound (α1-1). Obtained. The same measurement as in Example 1 was performed. Table 2 shows the results.

(Example 6)
0.5 g of the compound (α1-1), 4.5 g of methyltrimethoxysilane, 30 g of a 5 mmol / L acetic acid aqueous solution as a solvent, 2 g of urea as a base catalyst, and hexadecyltrimethylammonium bromide as a surfactant ( 0.75 g (manufactured by Tokyo Chemical Industry Co., Ltd.) was placed in a plastic container containing a magnetic stirrer, and stirred at room temperature for 60 minutes at a rotation speed of 1500 rpm to obtain a mixture. Except that this mixture was used, polysiloxane xerogels having a thickness of 1 mm and 10 mm were obtained in the same manner as in Example 1. The same measurement as in Example 1 was performed. Table 2 shows the results.

(Example 7)
Instead of using 5 g of the compound (α1-1), a thickness of 1 mm was obtained by the same method as in Example 1 except that 1 g of the compound (α1-1) and 4 g of tetramethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) were used. A 10 mm polysiloxane xerogel was obtained. The same measurement as in Example 1 was performed. Table 3 shows the results.

(Example 8)
Instead of using 5 g of the compound (α1-1), 2.5 g of the compound (α1-1) and 2.5 g of 1,6-bis (trimethoxysilyl) hexane (manufactured by Tokyo Chemical Industry Co., Ltd.) were used. Polysiloxane xerogels having a thickness of 1 mm and 10 mm were obtained in the same manner as in Example 1. The same measurement as in Example 1 was performed. Table 3 shows the results.

(Example 9)
The same method as in Example 1 except that 2.5 g of compound (α1-1) and 2.5 g of dimethyldimethoxysilane (manufactured by Tokyo Chemical Industry Co., Ltd.) were used instead of 5 g of compound (α1-1). As a result, polysiloxane xerogels having a thickness of 1 mm and 10 mm were obtained. The same measurement as in Example 1 was performed. Table 3 shows the results.

(Comparative Example 1)
Polysiloxane xerogels having a thickness of 1 mm and 10 mm were obtained in the same manner as in Example 1, except that 5 g of methyltrimethoxysilane was used instead of 5 g of the compound (α1-1). The same measurement as in Example 1 was performed. Table 4 shows the results.

(Comparative Example 2)
1 g of tetramethoxysilane, 4 g of ethanol, 4 g of water, 0.5 g of urea, and 0.5 g of cetyltrimethylammonium chloride were mixed at room temperature and stirred for 60 minutes to obtain a mixture. A methanol gel was obtained in the same manner as in Example 1 except that this mixture was used. The methanol gel was supercritically dried in the same manner as in Example 2 to obtain 1 mm and 10 mm thick polysiloxane xerogels. The same measurement as in Example 1 was performed. Table 4 shows the results.

  The polysiloxane gel of the present invention is useful as a heat insulating material, a transparent heat insulating layer of laminated glass, and the like. The laminated glass of the present invention is a window glass for automobiles (window shield, roof window, elevating window, side fixed window, backlight, roof window, etc.), window glass for vehicles such as window glass for railway vehicles, and window glass for buildings. It is useful as such.

1 laminated glass,
10 first glass plate,
12 a second glass plate,
14 transparent insulation layer,
16 first transparent adhesive layer,
18 Second transparent adhesive layer.

Claims (14)

It has at least one 6-membered ring selected from the group consisting of a ring structure represented by the following formula (a), a ring structure represented by the following formula (b), and a ring structure represented by the following formula (c) A polysiloxane gel comprising a three-dimensional network having a 6-membered ring-containing skeleton and a polysiloxane skeleton.

Here, * is a bond. The 6-membered ring-containing skeleton further has a linking group interposed between the 6-membered ring and the polysiloxane skeleton,
The polysiloxane gel according to claim 1, wherein the linking group has at least one group selected from the group consisting of an alkylene group, an oxyalkylene group, a polyether chain, and an arylene group.   3. The polysiloxane gel according to claim 1, wherein the six-membered ring-containing skeleton has a plurality of bonds, and at least two of the plurality of bonds are bonded to the polysiloxane skeleton. 4. .   The polysiloxane gel according to any one of claims 1 to 3, wherein the polysiloxane gel is a wet gel containing the three-dimensional network and a solvent.   The polysiloxane gel according to any one of claims 1 to 3, which is a xerogel comprising the three-dimensional network.   The polysiloxane gel according to any one of claims 1 to 5, which has a bending fracture stress of 0.3 MPa or more.   The polysiloxane gel according to any one of claims 1 to 6, wherein a 1-mm thickness conversion value of transmittance of light having a wavelength of 500 nm is 50% or more. It has at least one 6-membered ring selected from the group consisting of a ring structure represented by the following formula (a), a ring structure represented by the following formula (b), and a ring structure represented by the following formula (c) A method for producing a polysiloxane gel containing a three-dimensional network having a 6-membered ring-containing skeleton and a polysiloxane skeleton,
It has at least one 6-membered ring selected from the group consisting of a ring structure represented by the following formula (a), a ring structure represented by the following formula (b), and a ring structure represented by the following formula (c) A method for producing a polysiloxane gel, wherein a mixture containing a 6-membered ring-containing silane compound having a 6-membered ring-containing skeleton and a hydrolyzable silyl group and a solvent is gelled to obtain a wet gel.

Here, * is a bond. The 6-membered ring-containing skeleton of the 6-membered ring-containing silane compound further has a linking group interposed between the 6-membered ring and the hydrolyzable silyl group,
The method for producing a polysiloxane gel according to claim 8, wherein the linking group has at least one group selected from the group consisting of an alkylene group, an oxyalkylene group, a polyether chain, and an arylene group.   The method for producing a polysiloxane gel according to claim 8 or 9, wherein the 6-membered ring-containing silane compound has at least two hydrolyzable silyl groups.   The method for producing a polysiloxane gel according to any one of claims 8 to 10, wherein the mixture further includes another silane compound having a hydrolyzable silyl group.   The method for producing a polysiloxane gel according to any one of claims 8 to 11, wherein a xerogel is obtained by removing a solvent from the wet gel.   A heat insulating material comprising the polysiloxane gel according to claim 1. A first glass plate, a second glass plate, and a transparent heat insulating layer existing between the first glass plate and the second glass plate;
A laminated glass, wherein the transparent heat insulating layer is the polysiloxane gel according to any one of claims 1 to 7.

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