Latex With Isocyanate Crosslinker As Binder For Fibrous Substrates

• US 20070149077A1
• Filed: 12/18/2006
• Published: 06/28/2007
• Est. Priority Date: 12/22/2005
• Status: Active Grant

• Current Assignee: Lubrizol Advanced Materials Incorporated (Berkshire Hathaway Incorporated)
• Original Assignee: Noveon, Inc. (Berkshire Hathaway Incorporated)
• Inventors: Stanislawczyk, Vic, Wolfinger, Mark
• Granted Patent: US 7,455,909 B2
• Time in Patent Office: Days
• US Class Current: 442/152
• CPC Class Codes: C08G 18/706 the liquid medium being water
• CPC Class Codes: C08G 18/80 Masked polyisocyanates
• CPC Class Codes: D04H 1/587 characterised by the bonding agents used
• CPC Class Codes: D04H 1/64 the bonding agent being applied in wet state, e.g. chemical agents in dispersions or solutions
• CPC Class Codes: D21H 17/37 Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
• CPC Class Codes: D21H 17/57 Polyureas; Polyurethanes
• CPC Class Codes: D21H 21/18 Reinforcing agents
• CPC Class Codes: Y10T 428/31547 Of polyisocyanurate
• CPC Class Codes: Y10T 428/31551 Of polyamidoester [polyurethane, polyisocyanate, polycarbamate, etc.]
• CPC Class Codes: Y10T 442/2762 Coated or impregnated natural fiber fabric [e.g., cotton, wool, silk, linen, etc.]
• CPC Class Codes: Y10T 442/2861 Coated or impregnated synthetic organic fiber fabric
• CPC Class Codes: Y10T 442/2926 Coated or impregnated inorganic fiber fabric
• CPC Class Codes: Y10T 442/2992 Coated or impregnated glass fiber fabric
• CPC Class Codes: Y10T 442/611 Cross-sectional configuration of strand or fiber material is other than circular

Abstract

A polymeric dispersion in aqueous phase for use as a polymeric binder for paper and other nonwoven articles is described utilizing a polyisocyanate in combination with said polymeric binder to increase the ratio wet tensile/dry tensile strength. The polyisocyanate seems to be functioning by increasing the fiber to binder interaction rather than by simply increasing the strength/crosslink density of the binder. The polyisocyanate can be blocked isocyanate(s) or water dispersible isocyanate(s). The binder may or may not have isocyanate reactive species along the backbone.

Claims

1. A binder for a nonwoven composite of non-oleophilic fibrous material comprising:

a) a dispersed phase in an aqueous media of polymer from the polymerization of unsaturated monomer(s) in combination with,

b) a water dispersible and/or blocked polyisocyanate component dispersed in an aqueous media, said polyisocyanate present from 0.01 to about 20 weight percent based on the weight of the binder less the volatile portion of said aqueous media.

2. A fibrous construction comprising a binder according to claim 1 in combination with a major amount of non-oleophilic fibrous material formed into a nonwoven composite.

3. A fibrous construction according to claim 2, wherein said fibrous material is cellulosic, cotton, glass, polyester or blends thereof.

4. A fibrous construction according to claim 2, wherein said polyisocyanate component is present from about 0.1 to about 10 percent by weight based on the dry binder weight.

5. A fibrous construction according to claim 4, wherein said fibrous construction is formed into a paper, matt, or rope.

6. A fibrous construction according to claim 4, wherein said fibrous construction is formed into a reinforcing element for an unsaturated resin composition.

7. A fibrous construction according to claim 2, wherein said dispersed phase from polymerization of unsaturated monomer(s) is comprised of a) at least 30 weight percent repeating units from a C1-C8 alkyl(alk)acrylate or b) at least 30 weight percent a C₄ or C₅ diene monomer based on the total weight of the dispersed polymer phase.

8. A fibrous construction according to claim 2, wherein said fibrous material has an aspect ratio of at least 2:

1 and at least one weight average dimension of said fibrous material is at least 10 um.

9. A fibrous construction according to claim 8, wherein said polymer and said polyisocyanate of said dispersed phase is substantially simultaneously coagulated onto said fibrous material.

10. A fibrous construction according to claim 2, wherein said dispersed polymer phase is coagulated onto said fibrous material in such a manner that said polymer phase restricts said fibrous material from sliding past each other during tensile strength measurements.

11. A fibrous construction according to claim 2, wherein said polymer of said dispersed phase is substantially formaldehyde free during curing.

12. A fibrous construction according to claim 2, wherein said fibrous material and binder in a nonwoven having ratio of wet tensile to dry tensile of at least 0.20 after curing 3 minutes at 100°

C.

13. A fibrous construction according to claim 12, wherein said fibrous material and binder result in a nonwoven that has a 100% increase in the ratio of wet:

dry tensile strength over an otherwise identical fibrous construction lacking said polyisocyanate component after curing both samples 3 minutes at 100°

C.