LIQUID COMPOSITION FOR FORMING SILICA POROUS FILM AND SILICA POROUS FILM FORMED FROM SUCH LIQUID COMPOSITION

• US 20170015561A1
• Filed: 03/11/2015
• Published: 01/19/2017
• Est. Priority Date: 03/11/2014
• Status: Active Grant

• Current Assignee: Mitsubishi Materials Corporation
• Original Assignee: Mitsubishi Materials Corporation
• Inventors: Masuyama, Koutaro, Higano, Satoko, Yamasaki, Kazuhiko
• Granted Patent: US 10,457,561 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B01D 2325/0283 Pore size
• CPC Class Codes: B01D 53/228 characterised by specific membranes
• CPC Class Codes: B01D 67/0048 by sol-gel transition
• CPC Class Codes: B01D 71/027 Silicium oxide
• CPC Class Codes: B01J 21/08 Silica
• CPC Class Codes: B01J 35/23 in a colloidal state
• CPC Class Codes: B01J 37/0215 Coating
• CPC Class Codes: B01J 37/0236 Drying, e.g. preparing a suspension, adding a soluble salt and drying
• CPC Class Codes: C01B 33/126 Preparation of silica of undetermined type
• CPC Class Codes: C09D 1/00 Coating compositions, e.g. paints, varnishes or lacquers, based on inorganic substances

Abstract

A liquid composition for forming a silica porous film of the invention is prepared by mixing a hydrolyzate of tetramethoxysilane or tetraethoxysilane as a silicon alkoxide with a silica sol in which fumed silica particles having primary particles having a mean particle diameter of 40 nm or less and secondary particles having a mean particle diameter of 20 nm to 400 nm, that is greater than the mean particle diameter of the primary particles, are dispersed in a liquid medium, in which the mass ratio (AB) of the SiO₂ content (B) of the silica sol to the SiO₂ content (A) in the hydrolyzate is in a range of 1/99 to 60/40.

Claims

1. A liquid composition for forming a silica porous film which is prepared by mixing a hydrolyzate of tetramethoxysilane or tetraethoxysilane as a silicon alkoxide with a silica sol in which fumed silica particles having primary particles having a mean particle diameter of 40 nm or less and secondary particles having a mean particle diameter of 20 nm to 400 nm, that is greater than the mean particle diameter of the primary particles, are dispersed in a liquid medium,

wherein a mass ratio (A/B) of a SiO₂ content (B) of the silica sol to a SiO₂ content (A) in the hydrolyzate is in a range of 1/99 to 60/40.

2. A silica porous film forming method of forming a silica porous film using the liquid composition according to claim I.

4. The silica porous film forming method according to claim 2, comprising the steps of:

coating a substrate with the liquid composition; and

baking the substrate coated with the liquid composition to harden the liquid composition coated on the substrate.

3. A silica porous film comprising:

fumed silica particles having primary particles having a mean particle diameter of 40 nm or less and secondary particles having a mean particle diameter of 20 nm to 400 nm, that is greater than the mean particle diameter of the primary particles; and

an amorphous SiO₂ component existing between the fumed silica particles or between a coating film and a substrate,

wherein a mean hole diameter of the film is in a range of 10 nm to 200 nm.