Cement and skinning material based on a water-swellable clay, and method for producing segmented or skinned ceramic honeycomb structures

Patent metadata

Field	Value
Publication number	US-10214451-B2
Application number	US-201214362483-A
Country	US
Kind code	B2
Filing date	Dec 10, 2012
Priority date	Dec 15, 2011
Publication date	Feb 26, 2019
Grant date	Feb 26, 2019

Abstract

Skins and/or adhesive layers are formed on a porous ceramic honeycomb by applying a layer of a cement composition to a surface of the honeycomb and firing the cement composition. The cement composition contains a water-swellable clay, high aspect inorganic filler particles and water, and are nearly or completely devoid of particles smaller than 100 nm and a cellulosic polymer.

First claim

What is claimed is:

1. An uncured inorganic cement composition comprising:
a) 1 to 18% by weight of a water-swellable clay;
b) 20 to 70% by weight of non-water-swellable, non-fugitive, inorganic filler particles that have an equivalent diameter of greater than 250 nm;
c) 20 to 60% by weight of water;
d) larger than to less than 0.05% by weight of a water-soluble cellulosic polymer;
e) Larger than 0 to less than 0.25% by weight of inorganic particles having an equivalent diameter of 250 nm or less; and
f) 5 to 30% by weight of one or more porogens;
wherein the uncured cement composition is self-supporting with a shear viscosity of 1 to less than 28 Pa*s when measured by oscillating shear rheometry methods at 20° C., 1 rad/s oscillation and 5 MPa amplitude.

2. The uncured inorganic cement composition of claim 1 , wherein the water-swellable clay expands to a volume of at least 15 mL when 2 grams of the clay are added in small increments to room temperature distilled water.

3. The uncured inorganic cement composition of claim 1 , which contains from 1 to 7 wt-% of the water-swellable clay.

4. The uncured inorganic cement composition of claim 1 , wherein the inorganic filler particles include at least one high aspect ratio filler having an aspect ratio of 5 or greater.

5. The uncured inorganic cement composition of claim 4 which contains from 10 to 45 wt-% of the at least one high aspect ratio filler having an aspect ratio of 5 or greater.

6. The uncured inorganic cement composition of claim 4 wherein the at least one high aspect ratio filler having an aspect ratio of 5 or greater is a low-biopersistent fiber.

7. The uncured inorganic cement composition of claim 1 wherein the inorganic filler particles include alumina.

8. The uncured inorganic cement composition of claim 7 wherein the alumina and water-swellable clay are present in a weight ratio of from 0.25 to 2 parts of alumina to one part clay.

9. The uncured inorganic cement composition of claim 8 wherein the alumina and water-swellable clay are present in a weight ratio of from 0.3 to 1 part of alumina to one part clay.

10. The uncured inorganic cement composition of claim 7 wherein the alumina and water-swellable clay together constitute from 3 to 15 wt-% of the composition.

11. The uncured inorganic cement composition of claim 7 which contains from 10 to 35% by weight of low aspect ratio particles having an aspect ratio of less than 5 other than alumina or a water-swellable clay.

12. The uncured inorganic cement composition of claim 1 which includes:
a) 1 to 7% by weight of the water-swellable clay;
b) 0.75 to 4 parts by weight, per part by weight of the water-swellable clay, of alumina particles that have an effective diameter greater than 250 nm;
c) 10 to 70% by weight of inorganic filler particles that have an aspect ratio of at least 10;
d) 20 to 60% by weight of water;
e) greater than 0 to less than 0.05% by weight of a water-soluble cellulosic polymer;
f) greater than 0 to less than 0.25% by weight of inorganic particles having an equivalent diameter of 250 nm or less; and
g) 10 to 25% by weight of the one or more porogens;
wherein the composition is devoid of colloidal sol;
wherein uncured cement composition is self-supporting with a shear viscosity of 3 to less than 10 Pa·s when measured by oscillating shear rheometry methods at 20° C., 1 rad/s oscillation and 5 MPa amplitude.

13. The uncured cement composition of claim 1 which has a shear viscosity of 3 to 10 Pa·s when measured by oscillating shear rheometry methods at 20° C., 1 rad/s oscillation and 5 MPa amplitude.

14. A method of forming a honeycomb structure comprising forming a layer of the uncured inorganic cement composition of claim 1 on at least one surface of a ceramic honeycomb having porous walls and then firing the uncured inorganic cement composition and the ceramic honeycomb to form a cured cement layer on said at least one surface of the ceramic honeycomb.

15. The method of claim 14 , wherein the cured cement layer forms a peripheral skin on the ceramic honeycomb.

16. The method of claim 14 , wherein the cured cement layer forms a cement layer between segments of a segmented honeycomb structure.

17. The method of claim 14 , wherein fired cement composition has a CTE over the temperature range of 100° C.-600° C. that is within the range CTE honeycomb +1 ppm/° C. to CTE honeycomb −5 ppm, where CTE honeycomb is the coefficient of thermal expansion of the honeycomb.

18. The method of claim 17 wherein the inorganic filler particles include low-biopersistent inorganic fibers and low aspect ratio particles other than alumina or a water-swellable clay which have a CTE equal to or lower than that of the ceramic honeycomb.

19. The uncured cement composition of claim 1 , wherein the one or more porogens is wheat flour, wood flour, soy flour, potato starch, corn starch, corn meal, cellulose flour, and/or nut shell flour.

Assignees

• Dow Global Technologies Llc

Inventors

• Pyzik Aleksander J
• Allen Sharon
• Saucier Peter C

Classifications

• B29L2031/608

  Honeycomb structures · CPC title

• C04B37/00

  Joining burned ceramic articles with other burned ceramic articles or other articles by heating {(soldering and welding materials B23K35/24; laminated products B32B, E04C)} · CPC title

• C04B38/0006

  Honeycomb structures (from one or more corrugated sheets by winding or stacking C04B38/0083) · CPC title

• C04B37/005

  consisting of glass or ceramic material · CPC title

• C04B28/001 Primary

  containing unburned clay (polymer binder - clay mixtures used in well cementing C09K8/44) · CPC title