Process for making paper and nonwoven articles comprising synthetic microfiber binders

Patent metadata

Field	Value
Publication number	US-9617685-B2
Application number	US-201414249868-A
Country	US
Kind code	B2
Filing date	Apr 10, 2014
Priority date	Apr 19, 2013
Publication date	Apr 11, 2017
Grant date	Apr 11, 2017

Abstract

A process of making a paper or nonwoven article is provide. The process comprising:
a) providing a fiber furnish comprising a plurality of fibers and a plurality of binder microfibers, wherein the binder microfibers comprise a water non-dispersible, synthetic polymer; wherein the binder microfibers have a length of less than 25 millimeters and a fineness of less than 0.5 d/f; and wherein the binder microfibers have a melting temperature that is less than the melting temperature of the fibers; b) routing the fiber furnish to a wet-laid nonwoven process to produce at least one wet-laid nonwoven web layer; c) removing water from the wet-laid nonwoven web layer; and d) thermally bonding the wet-laid nonwoven web layer after step (c); wherein the thermal bonding is conducted at a temperature such that the surfaces of the binder microfibers at least partially melt without causing the fibers to melt thereby bonding the binder microfibers to the fibers to produce the paper or nonwoven article.

First claim

What is claimed is:

1. A process of making a paper or nonwoven article comprising a wet-laid nonwoven web layer, said process comprising:
a) providing a fiber furnish comprising a plurality of fibers and a plurality of binder microfibers, wherein said binder microfibers comprise a water non-dispersible, synthetic polymer; wherein said binder microfibers have a length of less than 25 millimeters and a fineness of less than 0.5 d/f; wherein said binder microfibers have a melting temperature that is less than the melting temperature of said fibers; wherein there is an absence of a binder other than said binder microfibers; and wherein the amount of said binder microfibers range from about 5 weight percent to about 90 weight percent of said nonwoven web layer;
b) routing said fiber furnish to a wet-laid nonwoven process to produce at least one wet-laid nonwoven web layer;
c) removing water from said wet-laid nonwoven web layer; and
d) thermally bonding said wet-laid nonwoven web layer after step (c); wherein said thermal bonding is conducted at a temperature such that the surfaces of said binder microfibers at least partially melt without causing said fibers to melt thereby bonding said binder microfibers to said fibers to produce said paper or nonwoven article.

2. The process of making a paper or nonwoven article according to claim 1 wherein said binder microfibers are produced by a process comprising:
(a) spinning at least one water dispersible sulfopolyester and one or more water non-dispersible synthetic polymers immiscible with the sulfopolyester into multicomponent fibers, wherein said multicomponent fibers have a plurality of domains comprising said water non-dispersible synthetic polymers whereby the domains are substantially isolated from each other by the sulfopolyester intervening between the domains; wherein said multicomponent fibers have an as-spun denier of less than about 15 denier per filament; wherein said water dispersible sulfopolyester exhibits a melt viscosity of less than about 12,000 poise measured at 240° C. at a strain rate of 1 rad/sec; and wherein said sulfopolyester comprises less than about 25 mole percent of residues of at least one sulfomonomer, based on the total moles of diacid or diol residues;
(b) cutting said multicomponent fibers of step a) to a length of less than 25 millimeters to produce cut multicomponent fibers; and
(c) contacting said cut multicomponent fibers with water to remove the sulfopolyester thereby forming a wet lap of binder microfibers comprising said water non-dispersible synthetic polymer.

3. The process of making a paper or nonwoven article according to claim 1 further comprising applying at least one coating to said nonwoven web layer.

4. The process of making a paper or nonwoven article according to claim 1 wherein said thermal bonding is accomplished by through-air heating or calendaring.

5. The process of making a paper or nonwoven article according to claim 1 wherein said wet-laid nonwoven process comprises routing a paperforming slurry to continuous screens.

6. The process of making a paper or nonwoven article according to claim 1 wherein said wet-laid nonwoven process comprises:
(a) optionally, rinsing said binder microfibers with water;
(b) adding water to said binder microfibers to produce a microfiber slurry;
(c) adding said fibers and optionally, additives to said microfiber slurry to produce said fiber furnish; and
(d) transferring said fiber furnish to said wet-laid nonwoven process to produce the nonwoven web layer.

7. The process of making a paper or nonwoven article according to claim 1 wherein said wet-laid nonwoven process comprises at least one screen, mesh, or sieve in order to remove the water from said fiber furnish.

8. The process of making a paper or nonwoven article according to claim 1 wherein said wet-laid nonwoven process comprises a Fourdrinier or inclined wire process.

9. The process of making a paper or nonwoven article according to claim 1 wherein said binder microfibers have a length of less than 10 millimeters.

10. The process of making a paper or nonwoven article according to claim 1 wherein said water non-dispersible, synthetic polymer is selected from the group consisting of polyolefins, polyesters, copolyesters, polyamides, polylactides, polycaprolactone, polycarbonate, polyurethane, acrylics, cellulose ester, and/or polyvinyl chloride.

11. The process of making a paper or nonwoven article according to claim 10 wherein said polyesters are at least one selected from the group consisting of polyethylene terephthalate homopolymer, polyethylene terephthalate copolymer, polybutylene terephthalate, polycyclohexylene cyclohexanedicarboxylate, polycyclohexylene terephthalate, and polytrimethylene terephthalate.

12. The process of making a paper or nonwoven article according to claim 1 wherein said fibers are at least one selected the group consisting of glass, cellulosic, and synthetic polymers.

13. The process of making a paper or nonwoven article according to claim 1 wherein said fibers are at least one selected from the group consisting of cellulosic fiber pulp, inorganic fibers, polyester fibers, nylon fibers, polyolefin fibers, rayon fibers, lyocell fibers, acrylic fibers, cellulose ester fibers, post consumer recycled fibers, and combinations thereof.

14. The process of making a paper or nonwoven article according to claim 1 wherein said nonwoven web layer comprises fibers in an amount of at least about 10 weight percent of the nonwoven web layer.

15. The process of making a paper or nonwoven article according to claim 1 further comprising adding at least one additive to said nonwoven web layer; and wherein said additive is selected from the group consisting of starches, fillers, light and heat stabilizers, antistatic agents, extrusion aids, dyes, anticounterfeiting markers, slip agents, tougheners, adhesion promoters, oxidative stabilizers, UV absorbers, colorants, pigments, opacifiers (delustrants), optical brighteners, fillers, nucleating agents, plasticizers, viscosity modifiers, surface modifiers, antimicrobials, antifoams, lubricants, thermostabilizers, emulsifiers, disinfectants, cold flow inhibitors, branching agents, oils, waxes, and catalysts.

16. The process of making a paper or nonwoven article according to claim 1 wherein said binder fibers have a cross-section that is essentially round or essentially wedge-shaped.

17. The process of making a paper or nonwoven article according to claim 1 wherein said binder fibers are ribbon fibers having a transverse aspect ratio of at least 2:1.

Assignees

• Eastman Chem Co

Inventors

• Clark Mark Dwight
• Dema Keh
• Sohn Sungkyun
• Smith Ernest Phillip
• Anderson Chris Delbert
• Everett Charles Stuart

Classifications

• D21H13/06

  Cellulose esters · CPC title

• D21H13/12

  from macromolecular compounds obtained by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• D21H13/02 Primary

  Synthetic cellulose fibres · CPC title

• D21H13/20

  from macromolecular compounds obtained otherwise than by reactions only involving carbon-to-carbon unsaturated bonds · CPC title

• D21H15/02

  characterised by configuration · CPC title