Cationically charged coating on hydrophobic polymer fibers with poly (vinyl alcohol) assist

• US 6,537,614 B1
• Filed: 12/18/1998
• Issued: 03/25/2003
• Est. Priority Date: 12/18/1998
• Status: Expired due to Term

• Current Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Original Assignee: Kimberly-Clark Worldwide Incorporated (Kimberly-Clark Corporation)
• Inventors: Wei, Ning, Lyng, Robert John, Varriale, Monica Graciela
• Primary Examiner(s): WEISBERGER, RICHARD C
• Application Number:
  US09/216,087
• Time in Patent Office: 1,558 Days
• Field of Search: 427/331, 427/372.2, 427/384, 264/296, 264/381, 264/41, 264/48
• US Class Current: 427/331
• CPC Class Codes: B01D 2239/0428 Rendering the filter material hydrophobic
• CPC Class Codes: B01D 2239/0492 on fibres
• CPC Class Codes: B01D 39/1623 of synthetic origin
• CPC Class Codes: D06M 15/333 of vinyl acetate; Polyvinylalcohol
• CPC Class Codes: D06M 15/55 Epoxy resins
• CPC Class Codes: D06M 15/59 Polyamides; Polyimides
• CPC Class Codes: D06M 15/61 Polyamines polyimines
• CPC Class Codes: D06M 23/10 Processes in which the treating agent is dissolved or dispersed in organic solvents; Processes for the recovery of organic solvents thereof
• CPC Class Codes: Y10T 428/249921 Web or sheet containing structurally defined element or component
• CPC Class Codes: Y10T 428/29 Coated or structually defined flake, particle, cell, strand, strand portion, rod, filament, macroscopic fiber or mass thereof
• CPC Class Codes: Y10T 428/2929 Bicomponent, conjugate, composite or collateral fibers or filaments [i.e., coextruded sheath-core or side-by-side type]
• CPC Class Codes: Y10T 428/2933 Coated or with bond, impregnation or core
• CPC Class Codes: Y10T 428/2967 Synthetic resin or polymer

Abstract

A hydrophobic polymer fiber having a cationically charged coating thereon, in which the coating includes a functionalized cationic polymer, such as an epichlorohydrin-functionalized polyamine or an epichlorohydrin-functionalized polyamido-amine, which has been crosslinked by heat. The present invention also provides a fibrous filter which includes hydrophobic polymer fibers having the foregoing cationically charged coating thereon. The present invention further provides a method of preparing a fibrous filter. The method involves providing a fibrous filter comprised of hydrophobic polymer fibers; treating the fibrous filter with an aqueous solution of a functionalized cationic polymer crosslinkable by heat under conditions sufficient to substantially coat the fibers with the functionalized cationic polymer, wherein the solution includes the functionalized cationic polymer, a poly(vinyl alcohol), a polar solvent for the poly(vinyl alcohol), and water; and treating the resulting coated fibrous filter with heat at a temperature and for a time sufficient to crosslink the functionalized cationic polymer present on the hydrophobic polymer fibers. The present invention additionally provides a method of preparing a fibrous filter. The method includes providing a fibrous filter comprised of hydrophobic polymer fibers; passing a solution of a functionalized cationic polymer crosslinkable by heat through the fibrous filter under conditions sufficient to substantially coat the fibers with the functionalized cationic polymer, wherein the solution includes the functionalized cationic polymer, a poly(vinyl alcohol), and water; and treating the resulting coated fibrous filter with heat at a temperature and for a time sufficient to crosslink the functionalized cationic polymer present on the hydrophobic polymer fibers.

Claims

1. A method of preparing a fibrous filter, the method comprising:

providing a fibrous filter comprised of hydrophobic polymer fibers;

treating the fibrous filter with an aqueous solution of a functionalized cationic polymer crosslinkable by heat under conditions sufficient to substantially coat the fibers with the functionalized cationic polymer, wherein the solution comprises the functionalized cationic polymer, a poly(vinyl alcohol), a polar solvent for the poly(vinyl alcohol), and water; and

treating the resulting coated fibrous filter with heat at a temperature and for a time sufficient to crosslink the functionalized cationic polymer present on the hydrophobic polymer fibers.

2. The method of claim 1, in which the functionalized cationic polymer is an epichlorohydrin-functionalized polyamine.

3. The method of claim 2, in which the functionalized cationic polymer is an epichlorohydrin-functionalized polyamido-amine.

4. The method of claim 1, in which the aqueous solution of a functionalized cationic polymer comprises:

from about 0.1 to about 2 percent by weight of the functionalized cationic polymer;

from about 0.1 to about 4 percent by weight of the poly(vinyl alcohol); and

from about 10 to about 50 percent by weight of the polar solvent;

with the remainder of the solution being water.

5. The method of claim 4, in which the polar solvent is isopropyl alcohol.

6. The method of claim 5, in which the aqueous solution of a functionalized cationic polymer comprises:

from about 0.2 to about 1 percent by weight of the functionalized cationic polymer;

from about 0.1 to about 2 percent by weight of the poly(vinyl alcohol); and

from about 15 to about 45 percent by weight of the isopropyl alcohol;

with the remainder of the solution being water.

7. A method of preparing a fibrous filter, the method comprising:

providing a fibrous filter comprised of hydrophobic polymer fibers;

passing a solution of a functionalized cationic polymer crosslinkable by heat through the fibrous filter under conditions sufficient to substantially coat the fibers with the functionalized cationic polymer, wherein the solution comprises the functionalized cationic polymer, a poly(vinyl alcohol), and water; and

treating the resulting coated fibrous filter with heat at a temperature and for a time sufficient to crosslink the functionalized cationic polymer present on the hydrophobic polymer fibers.

8. The method of claim 7, in which the functionalized cationic polymer is an epichlorohydrin-functionalized polyamine.

9. The method of claim 8, in which the functionalized cationic polymer is an epichlorohydrin-functionalized polyamido-amine.

10. The method of claim 7, in which the aqueous solution of a functionalized cationic polymer comprises:

from about 0.1 to about 4 percent by weight of the functionalized cationic polymer; and

from about 0.1 to about 2 percent by weight of the poly(vinyl alcohol);

with the remainder of the solution being water.

11. The method of claim 10, in which the polar solvent is isopropyl alcohol.

12. The method of claim 11, in which the aqueous solution of a functionalized cationic polymer comprises:

from about 0.2 to about 2 percent by weight of the functionalized cationic polymer; and

from about 0.1 to about 1 percent by weight of the poly(vinyl alcohol);

with the remainder of the solution being water.