Using recycled waste water to make nonwoven fibrous materials suitable for use in a pollution control device or in a firestop

Patent metadata

Field	Value
Publication number	US-10995454-B2
Application number	US-201415102393-A
Country	US
Kind code	B2
Filing date	Dec 12, 2014
Priority date	Dec 19, 2013
Publication date	May 4, 2021
Grant date	May 4, 2021

Abstract

A method of making nonwoven fibrous materials suitable for use in a pollution control device or as a firestop, where the method comprises: providing a first slurry comprising water, first inorganic fibers, a first organic binder, and a first neutral pH flocculent; removing first waste water from the first slurry; optionally forming a first nonwoven fibrous material from the first slurry; providing a second slurry comprising a quantity of the first waste water, an optional quantity of relatively clean water, second inorganic fibers, a second organic binder, and a second flocculent that is the same and/or a different flocculent than that used in the first slurry; and forming a second nonwoven fibrous material from the second slurry. The addition of the first waste water in the second slurry does not adversely affect the flocculation of the second organic binder in the second slurry.

First claim

What is claimed is:

1. A method of making nonwoven fibrous materials suitable for use in a pollution control device or as a firestop, said method comprising:
providing a first slurry comprising water, first inorganic fibers, a first organic binder, and a first neutral pH flocculent, where the first slurry is used to form a first nonwoven fibrous material suitable for use in a pollution control device or as a firestop;
removing first waste water from the first slurry;
optionally forming a first nonwoven fibrous material from the first slurry;
providing a second slurry comprising a quantity of the first waste water, an optional quantity of relatively clean water, second inorganic fibers, a second organic binder, and a second flocculent that is the same and/or a different flocculent than that used in the first slurry; and
forming a second nonwoven fibrous material from the second slurry,
wherein the addition of the first waste water in the second slurry does not adversely affect the flocculation of the second organic binder in the second slurry, and the second nonwoven fibrous material is suitable for use in a pollution control device or as a firestop.

2. The method according to claim 1 , wherein the second flocculent comprises a second neutral pH flocculent, which is the same as or a different flocculent than that used in the first slurry, and said method further comprises:
removing a quantity of a second waste water from the second slurry;
providing a third slurry comprising a quantity of the second waste water, an optional quantity of relatively clean water, third inorganic fibers, a third organic binder, and a third neutral pH flocculent; and
forming a third nonwoven fibrous material from the third slurry,
wherein the addition of the second waste water in the third slurry does not adversely affect the flocculation of the third organic binder in the third slurry, and the third nonwoven fibrous material is suitable for use in a pollution control device or as a firestop.

3. The method according to claim 1 , wherein for each additional N th slurry, said method further comprises:
providing an N th slurry comprising a quantity of waste water removed from a previous slurry, an optional quantity of relatively clean water, N th inorganic fibers, an N th organic binder, and an N th neutral pH flocculent;
forming an N th nonwoven fibrous material from the N th slurry,
wherein N is a whole number greater than or equal to 4, and the addition of the N th −1 waste water in the N th slurry does not adversely affect the flocculation of the N th organic binder in the N th slurry, and the N th nonwoven fibrous material is suitable for use in a pollution control device or as a firestop.

4. The method according to claim 1 , wherein the organic binder in at least one slurry comprises at least one polymer having anionic groups.

5. The method according to claim 1 , wherein at least one neutral pH flocculent comprises an organic polymer having cationic groups.

6. The method according to claim 1 , wherein at least one neutral pH flocculent comprises a metal cation.

7. The method according to claim 1 , wherein at least one slurry exhibits a pH in the range of from about 5.5 up to and including about 8.5.

8. The method according to claim 1 , wherein each slurry containing waste water has a total water content comprising in the range of from at least about 10%.

9. The method according to claim 1 , wherein said forming is a slurry molding process.

10. The method according to claim 1 , wherein each nonwoven fibrous material is in the form of an individually molded nonwoven fibrous material structure having a two-dimensional or three-dimensional shape.

11. The method according to claim 1 , wherein at least one nonwoven fibrous material is in the form of (a) at least one mounting mat operatively adapted for use in mounting a pollution control element in a pollution control device, (b) at least one end cone insulator operatively adapted for use in insulating an end cone region of a pollution control device, (c) at least one fire stop.

12. A slurry for making nonwoven fibrous materials, said slurry comprising:
a quantity of a first waste water removed from a prior slurry comprising water, first inorganic fibers, a first organic binder, and a first neutral pH flocculent;
an optional quantity of relatively clean water that is commercially acceptable for use in the slurry and is not waste water;
second inorganic fibers;
a second organic binder; and
an optional second neutral pH flocculent,
wherein the amount of first neutral pH flocculent present in the prior slurry causes the first waste water to maintain a relatively neutral pH.

13. The slurry according to claim 12 , wherein at least the first neutral pH flocculent comprises an organic polymer having cationic groups.

14. The slurry according to claim 12 , wherein at least the first neutral pH flocculent further comprises a metal cation.

15. The slurry according to claim 12 , wherein the flocculent is selected from the group consisting of Flocculent 1 to Flocculent 30, and any combination thereof.

16. The slurry according to claim 12 , wherein each slurry exhibits a pH in the range of from about 5.5 up to and including about 8.5.

17. The slurry according to claim 12 , further comprising:
a quantity of relatively clean water that is commercially acceptable for use in the slurry and is not waste water; and
a second flocculent that is the same as, or a different flocculent than, that used in the prior slurry;
forming a second nonwoven fibrous material from the second slurry,
wherein the addition of the first waste water in the does not adversely affect the flocculation of the second organic binder.

Assignees

• 3M Innovative Properties Co

Inventors

• Merry Richard P
• Harding Ian R I
• Howorth Gary F

Classifications

• D21H13/36 Primary

  Inorganic fibres or flakes · CPC title

• F16L59/145

  providing fire-resistance · CPC title

• F16L59/026

  Mattresses, mats, blankets or the like · CPC title

• F01N13/18

  Construction facilitating manufacture, assembly, or disassembly · CPC title

• D21H21/10

  Retention agents or drainage improvers · CPC title