Thermal insulator and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-9950963-B2
Application number	US-201615143007-A
Country	US
Kind code	B2
Filing date	Apr 29, 2016
Priority date	Dec 22, 2010
Publication date	Apr 24, 2018
Grant date	Apr 24, 2018

Abstract

A thermal insulator with both excellent heat insulation and strength and a method of manufacturing the thermal insulator are provided.
A thermal insulator according to the present invention includes metal oxide fine particles with an average particle diameter equal to or smaller than 50 nm and a reinforcing fiber, wherein the thermal insulator has a bridge structure between the metal oxide fine particles which is formed by elution of part of the metal oxide fine particles. A method of manufacturing a thermal insulator according to the present invention includes a curing step of curing a dry pressed compact including metal oxide fine particles with an average particle diameter equal to or smaller than 50 nm and a reinforcing fiber under a pressurized vapor saturated atmosphere at a temperature equal to or higher than 100° C. for four hours and a drying step of drying the cured dry pressed compact.

First claim

The invention claimed is:

1. A method of manufacturing a thermal insulator, comprising:
a curing step of curing a dry pressed compact including metal oxide fine particles with an average particle diameter equal to or smaller than 50 nm and a reinforcing fiber under a pressurized vapor saturated atmosphere at a temperature equal to or higher than 100° C.,
wherein the metal oxide fine particles include alumina fine particles.

2. The method of manufacturing a thermal insulator according to claim 1 , wherein
in the curing step, part of the metal oxide fine particles is eluted between the metal oxide fine particles to form a liquid bridge structure, and
in a drying step, the bridge structure is solidified.

3. The method of manufacturing a thermal insulator according to claim 1 , wherein the metal oxide fine particles include silica fine particles.

4. The method of manufacturing a thermal insulator according to claim 1 , wherein the dry pressed compact includes 50 to 98 mass % of the metal oxide fine particles and 2 to 20 mass % of the reinforcing fiber.

5. The method of manufacturing a thermal insulator according to claim 1 , wherein
the dry pressed compact does not comprise a binder.

6. The method of manufacturing a thermal insulator according to claim 1 , further comprising:
a step of mixing the metal oxide fine particles and the reinforcing fiber by a dry method to fabricate a dry mixture; and
a step of pressure-forming the dry mixture by a dry method to fabricate the dry pressed compact.

7. The method of manufacturing a thermal insulator according to claim 1 , wherein the content of the alumina fine particles is 20 mass % or more.

8. The method of manufacturing a thermal insulator according to claim 1 , wherein the dry pressed compact further includes a radiating and scattering material.

9. The method of manufacturing a thermal insulator according to claim 8 , wherein the dry pressed compact includes:
50 to 98 mass % of the metal oxide fine particles;
2 to 20 mass % of the reinforcing fiber; and
5 to 40 mass % of the radiating and scattering material.

10. The method of manufacturing a thermal insulator according to claim 1 , wherein the reinforcing fiber has an average fiber length of equal to or larger than 1 mm and equal to or smaller than 10 mm.

11. The method of manufacturing a thermal insulator according to claim 2 , wherein
the bridge structure comprises a portion bridging an alumina fine particle and a silica fine particle; and
the thermal insulator comprises alumina fine particles equal to or larger than 10 mass % and silica fine particles equal to or larger than 5 mass % based on the mass of the thermal insulator.

Assignees

• Nichias Corp

Inventors

• Sakamoto Akifumi
• Goto Yoshihiko
• Ito Yasuo
• Maeda Ken

Classifications

• Y10T428/268

  Monolayer with structurally defined element · CPC title

• C04B40/0259

  Hardening promoted by a rise in pressure (C04B40/024 takes precedence) · CPC title

• C04B30/02 Primary

  containing fibrous materials · CPC title

• C04B40/0263

  Hardening promoted by a rise in temperature (C04B40/024 takes precedence) · CPC title

• B28B11/24

  for curing, setting or hardening (processes for influencing or modifying the setting or hardening ability of mortars, concrete or artificial stone compositions, in general C04B40/00) · CPC title