Wicking nonwoven mat from wet-laid process

Patent metadata

Field	Value
Publication number	US-2016268640-A1
Application number	US-201514642273-A
Country	US
Kind code	A1
Filing date	Mar 9, 2015
Priority date	Mar 9, 2015
Publication date	Sep 15, 2016
Grant date	—

Abstract

Examples of the present technology may include a method of making a non-woven fiber mat. The wet nonwoven fiber mat may include a first plurality of first glass fibers and a second plurality of second glass fibers. The first plurality of first glass fibers may have nominal diameters of less than 5 μm, and the second plurality of second glass fibers may have nominal diameters of greater than 6 μm. The method may further include curing the binder composition to produce the nonwoven fiber mat. The nonwoven fiber mat may have an average 40 wt. % sulfuric acid wick height of between about 1 cm and about 5 cm after exposure to 40 wt. % sulfuric acid for 10 minutes conducted according to method ISO8787, and the nonwoven fiber mat may have a total normalized tensile strength greater than 2 (lbf/in)/(lb/sq) for a sq (100 ft 2 ).

First claim

What is claimed is:

1 . A method of making a nonwoven fiber mat for use in a lead-acid battery, the method comprising:
adding a binder composition to a wet nonwoven fiber mat, wherein:
the wet nonwoven fiber mat comprises a first plurality of first glass fibers and a second plurality of second glass fibers,
the first plurality of first glass fibers has nominal diameters of less than 5 μm,
the second plurality of second glass fibers has nominal diameters of greater than 6 μm, and
the first plurality of first glass fibers comprises between about 10% and about 50% by weight of the combined weight of the first plurality of first glass fibers and the second plurality of second glass fibers; and
curing the binder composition to produce the nonwoven fiber mat, wherein:
the nonwoven fiber mat has an average 40 wt. % sulfuric acid wick height of between about 1 cm and about 5 cm after exposure to 40 wt. % sulfuric acid for 10 minutes conducted according to method ISO8787, and
the nonwoven fiber mat has a total normalized tensile strength of greater than 2 (lbf/in)/(lb/sq).

2 . The method of claim 1 , wherein the nonwoven fiber mat has a Cobb 60 degree of less than 1.

3 . The method of claim 1 , wherein the first plurality of first glass fibers has an average diameter of between 0.5 μm and 1.0 μm.

4 . The method of claim 1 , wherein the first plurality of first glass fibers has an average diameter of about 0.7 μm.

5 . The method of claim 1 , wherein the first plurality of first glass fibers comprises between about 30% and about 40% by weight of the combined weight of the first plurality of first glass fibers and the second plurality of second glass fibers.

6 . The method of claim 1 , wherein the first plurality of first glass fibers comprises between about 40% and about 50% by weight of the combined weight of the first plurality of first glass fibers and the second plurality of second glass fibers.

7 . The method of claim 1 , wherein the first plurality of first glass fibers comprises between about 20% and about 30% by weight of the combined weight of the first plurality of first glass fibers and the second plurality of second glass fibers.

8 . The method of claim 1 , wherein the first plurality of first glass fibers comprises between about 10% and about 20% by weight of the combined weight of the first plurality of first glass fibers and the second plurality of second glass fibers.

9 . The method of claim 1 , wherein the second plurality of second glass fibers has an average diameter of between about 8 μm and about 13 μm.

10 . The method of claim 1 , wherein:
the first glass fibers comprise a first glass composition, the second glass fibers comprise a second glass composition, and the first glass composition is different from the second glass composition.

11 . The method of claim 1 , wherein the method further comprises:
mixing the first plurality of first glass fibers and the second plurality of second glass fibers to form a slurry prior to adding the binder composition, and maintaining a pH of the slurry at about 5 or higher.

12 . The method of claim 1 , wherein the method further comprises:
mixing the first plurality of first glass fibers and the second plurality of second glass fibers to form a slurry prior to adding the binder composition, and maintaining a pH of the slurry at between about 7 and about 8.5.

13 . The method of claim 1 , wherein the binder composition comprises a powdered filler.

14 . The method of claim 13 , wherein the powdered filler is hydrophilic and acid-resistant.

15 . The method of claim 13 , wherein the powdered filler comprises between about 0.1% and about 20% by weight of the nonwoven fiber mat.

16 . The method of claim 13 , wherein the powdered filler is precipitated silica.

17 . The method of claim 1 , wherein the method further comprises blowing air through the wet nonwoven fiber mat.

18 . The method of claim 1 , wherein the nonwoven fiber mat has an average 40 wt. % sulfuric acid wick height of between about 2 cm and about 4 cm after exposure to 40 wt. % sulfuric acid for 10 minutes conducted according to method ISO8787.

19 . The method of claim 1 , wherein the nonwoven fiber mat has a total normalized tensile strength of greater than 7 (lbf/in)/(lb/sq).

20 . The method of claim 1 , wherein the nonwoven fiber mat has a total normalized tensile strength of greater than 14 (lbf/in)/(lb/sq).

21 . The method of claim 1 , wherein the nonwoven fiber mat has a total normalized tensile strength of greater than 28 (lbf/in)/(lb/sq).

22 . The method of claim 1 , wherein the method further comprises:
mixing the first plurality of first glass fibers and the second plurality of second glass fibers to form a slurry prior to adding the binder composition; and drying the wet nonwoven fiber mat, wherein the mixing, adding, and drying operations are continuous processes.

23 . A lead-acid battery comprising:
a positive electrode; a negative electrode; and a nonwoven fiber mat disposed adjacent the positive electrode or the negative electrode, wherein:
the nonwoven fiber mat comprises a first plurality of first glass fibers having nominal diameters of less than 5 μm,
the nonwoven fiber mat comprises a second plurality of second glass fibers having nominal diameters greater than 6 μm,
the first plurality of first glass fibers comprises between about 10% and about 50% by weight of the combined weight of the first plurality of first glass fibers and the second plurality of second glass fibers,
the nonwoven fiber mat comprises a binder composition,
the nonwoven fiber mat has an average 40 wt. % sulfuric acid wick height of between about 1 cm and about 5 cm after exposure to 40 wt. % sulfuric acid for 10 minutes conducted according to method ISO8787, and
the nonwoven fiber mat has a total normalized tensile strength of greater than 2 (lbf/in)/(lb/sq).

24 . The lead-acid battery of claim 23 , wherein the nonwoven fiber mat further comprises synthetic precipitated silica.

25 . A method of making a pasting paper for a battery, the method comprising:
applying an acid-resistant binder composition to a wet-laid mixture of glass fibers to form a wet nonwoven fiber mat, wherein:
the mixture of glass fibers comprises a first plurality of microfibers having an average diameter of between 0.5 μm and 1.0 μm,
the mixture of glass fibers comprises a second plurality of coarse fibers having an average diameter greater than or equal to 8 μm, and
the mass ratio of the first plurality of microfibers to the second plurality of coarse fibers is between about 1:5 and about 1:1;
drying the wet nonwoven fiber mat; and curing the acid-resistant binder composition to produce a pasting paper, wherein:
the pasting paper has an average 40 wt. % sulfuric acid wick height of between about 1 cm and about 5 cm after exposure to 40 wt. % sulfuric acid for 10 minutes conducted according to method ISO8787, and
the pasting paper has a total normalized tensile strength of greater than 7 (lbf/in)/(lb/sq).

Assignees

• Johns Manville

Inventors

• Guo Zhihua
• Nandi Souvik
• Asrar Jawed
• Dietz Iii Albert G

Classifications

• D10B2505/00

  Industrial · CPC title

• D04H1/4218

  Glass fibres · CPC title

• D10B2401/022

  hydrophylic · CPC title

• H01M10/12 Primary

  Construction or manufacture · CPC title

• H01M4/62

  Selection of inactive substances as ingredients for active masses, e.g. binders, fillers · CPC title