Porous body, honeycomb filter, method for producing porous body, and method for producing honeycomb filter

Patent metadata

Field	Value
Publication number	US-10099166-B2
Application number	US-201514667998-A
Country	US
Kind code	B2
Filing date	Mar 25, 2015
Priority date	Mar 28, 2014
Publication date	Oct 16, 2018
Grant date	Oct 16, 2018

Abstract

A porous body constituting a porous partition wall 44 of a honeycomb filter 30 has a porosity P of 20% to 60%, a permeability k of 1 μm 2 or more and satisfies k≥0.2823 P−10.404. The porous body is obtained by a method for producing, for example, includes (a) a step of acquiring porous body data representing a temporary porous body having porosity higher than target porosity, (b) a step of deriving information about a flow rate for each space voxel during passage of a fluid through inside of the porous body, (c) a step of preferentially replacing the voxel having a low flow rate among the space voxels with the object voxel, and adjusting the porosity of the porous body data to the target porosity, and (d) a step of forming a porous body based on the porous body data after replacement.

First claim

What is claimed is:

1. A method for producing a porous body including the steps of;
(a) a step of acquiring porous body data which is data representing a temporary porous body having porosity higher than target porosity, and which associates position information indicating a three-dimensional position of a voxel with voxel type information containing information capable of discriminating whether the voxel is a space voxel representing space or an object voxel representing an object;
(b) a step of deriving information about a flow rate for each space voxel during passage of a fluid through inside of the porous body represented by the porous body data by performing fluid analysis based on the porous body data;
(c) a step of preferentially replacing a voxel having a low flow rate among the space voxels in the porous body data with an object voxel based on the information about a flow rate, and adjusting the porosity of the porous body data to the target porosity; and
(d) a step of forming a porous body based on the porous body data after replacement.

2. The method for producing the porous body according to claim 1 , wherein the target porosity is 20% to 60%.

3. The method for producing the porous body according to claim 2 , wherein in the step (c), a voxel having a low flow rate among the space voxels adjacent to an object voxel is preferentially replaced with an object voxel.

4. The method for producing the porous body according to claim 3 , wherein in the step (d), the porous body based on the porous body data after replacement is formed directly by a three-dimensional shaping method.

5. The method for producing the porous body according to claim 3 , wherein the step (d) includes the steps of;
(d1) a step of forming a reverse porous body in which a space voxel is taken as an object and an object voxel is taken as space by a three-dimensional shaping method based on the porous body data after replacement;
(d2) a step of forming a green porous body by filling the spaces of the reverse porous body with a raw material slurry of the porous body; and
(d3) a step of burning out the reverse porous body by firing the green porous body to form the porous body.

6. The method for producing the porous body according to claim 2 , wherein in the step (d), the porous body based on the porous body data after replacement is formed directly by a three-dimensional shaping method.

7. The method for producing the porous body according to claim 2 , wherein the step (d) includes the steps of;
(d1) a step of forming a reverse porous body in which a space voxel is taken as an object and an object voxel is taken as space by a three-dimensional shaping method based on the porous body data after replacement;
(d2) a step of forming a green porous body by filling the spaces of the reverse porous body with a raw material slurry of the porous body; and
(d3) a step of burning out the reverse porous body by firing the green porous body to form the porous body.

8. The method for producing the porous body according to claim 1 , wherein in the step (c), a voxel having a low flow rate among the space voxels adjacent to an object voxel is preferentially replaced with an object voxel.

9. The method for producing the porous body according to claim 8 , wherein in the step (d), the porous body based on the porous body data after replacement is formed directly by a three-dimensional shaping method.

10. The method for producing the porous body according to claim 8 , wherein the step (d) includes the steps of;
(d1) a step of forming a reverse porous body in which a space voxel is taken as an object and an object voxel is taken as space by a three-dimensional shaping method based on the porous body data after replacement;
(d2) a step of forming a green porous body by filling the spaces of the reverse porous body with a raw material slurry of the porous body; and
(d3) a step of burning out the reverse porous body by firing the green porous body to form the porous body.

11. The method for producing the porous body according to claim 1 , wherein in the step (c), a voxel having the lowest flow rate is first replaced with an object voxel.

12. The method for producing the porous body according to claim 11 , wherein in the step (d), the porous body based on the porous body data after replacement is formed directly by a three-dimensional shaping method.

13. The method for producing the porous body according to claim 11 , wherein the step (d) includes the steps of;
(d1) a step of forming a reverse porous body in which a space voxel is taken as an object and an object voxel is taken as space by a three-dimensional shaping method based on the porous body data after replacement;
(d2) a step of forming a green porous body by filling the spaces of the reverse porous body with a raw material slurry of the porous body; and
(d3) a step of burning out the reverse porous body by firing the green porous body to form the porous body.

14. The method for producing the porous body according to claim 1 , wherein in the step (d), the porous body based on the porous body data after replacement is formed directly by a three-dimensional shaping method.

15. The method for producing the porous body according to claim 1 , wherein the step (d) includes the steps of;
(d1) a step of forming a reverse porous body in which a space voxel is taken as an object and an object voxel is taken as space by a three-dimensional shaping method based on the porous body data after replacement;
(d2) a step of forming a green porous body by filling the spaces of the reverse porous body with a raw material slurry of the porous body; and
(d3) a step of burning out the reverse porous body by firing the green porous body to form the porous body.

16. A method for producing a honeycomb filter using the method for producing the porous body according to claim 15 ,
wherein in the step (c), porous partition wall data is formed based on the porous body data after replacement, the porous partition wall data being data representing a porous partition wall which forms a plurality of cells serving as flow passages of a fluid, and associating the position information with the voxel type information,
in the step (d1), a reverse porous partition wall in which a space voxel is taken as an object and an object voxel is taken as space is formed by the three-dimensional shaping method based on the porous partition wall data,
in the step (d2), a green porous partition wall is formed by filling the spaces of the reverse porous partition wall with the raw material slurry,
in the step (d3), the reverse porous partition wall is burned out by firing the green porous partition wall to form a porous partition wall which forms the cells each having open both ends,
the step (d) includes a step (d4) of forming a sealed portion in each of the plurality of cells of the formed porous partition wall so that a cell in which one of the ends is opened and the other is sealed and a cell in which one of the ends is sealed and the other is opened are alternately arranged.

Assignees

• Ngk Insulators Ltd

Inventors

• Sakashita Satoshi
• Nagaoka Hiroyuki

Classifications

• C04B35/6365

  Cellulose or derivatives thereof · CPC title

• C04B2111/0081

  as catalysts or catalyst carriers · CPC title

• C04B2235/3826

  Silicon carbides · CPC title

• C04B35/62625

  Wet mixtures · CPC title

• C04B14/324

  Silicon carbide · CPC title