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Process for producing silica aerogel

A silicon dioxide and aerogel technology, applied in the directions of silicon dioxide, silicon oxide, chemical instruments and methods, etc., can solve the problems of complex manufacturing process, product properties depend on molecular weight distribution, and reaction solution preparation takes a long time.

Inactive Publication Date: 2007-06-20
DAINATSUKUSU +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0008] However, in the methods of Japanese Patent Publication No. 8-29952 and Japanese Patent Laid-Open No. 7-41374, since water-soluble polymer compounds are used, the preparation of the reaction solution takes a long time, and the properties of the product depend on the molecular weight distribution. , and the stage of making the gel and the stage of solvent replacement are separated, and the manufacturing process becomes complicated
[0009] In addition, in the gel drying methods of JP-A-8-29952 and JP-A-7-41374, when the solvent is removed from the alcogel, there is also a stress caused by capillary action inside the alcogel so that the gel The problem of shrinkage rupture

Method used

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  • Process for producing silica aerogel
  • Process for producing silica aerogel
  • Process for producing silica aerogel

Examples

Experimental program
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preparation example Construction

[0024] The first method of producing silica airgel according to the present invention is characterized in that a silicon compound having a hydrolyzable functional group and a hydrophobic functional group in the molecule is added to a solution in which a surfactant is dissolved in an acidic aqueous solution, and hydrolyzed to form a gel. And after curing, the gel is supercritically dried.

[0025] A silicon compound having a hydrolyzable functional group and a hydrophobic functional group in the molecule is used as a starting material of the sol-gel method.

[0026] A substance having a hydrolyzable functional group and a hydrophobic functional group in a molecule shows affinity for a hydrophilic solvent and a hydrophobic solvent in a solution, respectively, and can form a fine phase-separated structure at the level of a mesoscopic mirror.

[0027] As the silicon compound, an alkyl silicon alkoxide is preferable. In particular, when a silica airgel is produced using methyltrime...

Embodiment 1

[0048] Mix 9.5 g of methyltrimethoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., LS-530, hereinafter abbreviated as "MTMS") and 5.0 g of nonionic surfactant, polyethylene glycol (10) nonyl Phenyl ether (manufactured by NOF Co., Ltd., NS210, hereinafter abbreviated as "NS210") was uniformly dissolved, and a 1 mol / L nitric acid aqueous solution was added to carry out a hydrolysis reaction while stirring the solution under ice cooling. Then, the mixture was stirred for 5 minutes under ice cooling while maintaining the above state. At this time, by changing the amount of nitric acid aqueous solution, MTMS:NS210:H 2 O=1:0.1:(1.8, 2.0, 2.2). They were then designated as MN21018, MN21020 and MN21022 according to the molar ratio of water added. Then, it was left to stand at 40°C in an airtight container for gelation. After gelation, the gel was aged by standing at 40° C. for 39 hours under airtight conditions. Next, the undried wet gel was immersed in 2-propanol for solve...

Embodiment 2

[0062] After mixing 1.819g of 1mol / L nitric acid aqueous solution, 7.315g of formamide and 5.0g of nonionic surfactant NS210 to make it dissolve uniformly, add 10.32g of tetramethoxysilane (Shin-Etsu Chemical Co., Ltd. Co., Ltd. product, LS-540, hereinafter abbreviated as "TMOS".) Hydrolysis reaction was carried out. Then, the mixture was stirred for 5 minutes under ice cooling while maintaining the above state. At this time, TMOS:formamide:H 2 The molar ratio of O is =1:2.4:1.4. This composition is referred to as "TF14". Then, it was left to stand at 40°C in an airtight container for gelation. After gelation, the gel was aged by standing at 80° C. for 48 hours under airtight conditions.

[0063] Then, a supercritical drying operation was performed in the same manner as in Example 1. The micropore diameter distribution of samples without cracks after supercritical drying was measured by mercury intrusion method. The result shown below is obtained. Scanning electron micr...

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Abstract

A surfactant is dissolved in an acidic aqueous solution. A silicon compound having a hydrolysable functional group and a hydrophobic functional group is added thereto to conduct hydrolysis reaction and yield a gel. After the gel is solidified, the gel is supercritically dried. Thus, a silica aerogel having a regulated pore diameter and pore diameter distribution can be produced. The surfactant preferably is one of or a mixture of two or more of nonionic surfactants, cationic surfactants, and anionic surfactants. The silica aerogel produced is usable in applications such as a heat insulator for solar-heat collector panals and a heat-insulating window material for housing.

Description

technical field [0001] The present invention relates to a method for producing silica aerogel. Background technique [0002] Silica airgel is a well-known thermal insulation material due to its high porosity and extremely low thermal conductivity. Due to its high visible light transmittance and low specific gravity of about 0.1, it is relatively light, so it is currently being used for solar heat collection. Thermal insulation materials for appliance covers and thermal insulation window materials for residential buildings. [0003] Generally, inorganic porous bodies such as silica aerogels are prepared by liquid-phase reaction, that is, sol-gel method. The alcohol gel used in the production of the existing silica airgel is obtained by diluting the silicon compound in an alcohol solvent to make the silica content reach about 4-5%, and hydrolyzing and polycondensing it with an acidic or alkaline catalyst of. In the above process, conditions such as temperature and humidity ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B33/16C01B33/158
CPCC01B33/1585
Inventor 中西和树金森主祥会泽守和泉博明
Owner DAINATSUKUSU