High temperature stable nonwoven webs based on multi-layer blown microfibers

• US 5,232,770 A
• Filed: 09/30/1991
• Issued: 08/03/1993
• Est. Priority Date: 09/30/1991
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Joseph, Eugene G.
• Primary Examiner(s): Bell, James J.
• Application Number:
  US07/769,095
• Time in Patent Office: 673 Days
• Field of Search: 428/284, 428/287, 428/297, 428/298, 428/296, 428/903, 428/288, 156/167
• US Class Current: 442/345
• CPC Class Codes: B01D 2239/0407 comprising particulate additives, e.g. adsorbents apparatus incorporating gas filtering material B01D46/0036
• CPC Class Codes: B01D 2239/0457 Specific fire retardant or heat resistant properties apparatus incorporating such gas filtering material B01D46/0093
• CPC Class Codes: B01D 2239/0622 Melt-blown
• CPC Class Codes: B01D 2239/064 The fibres being mixed
• CPC Class Codes: B01D 2239/065 More than one layer present in the filtering material apparatus incorporating such gas filtering material B01D2275/10
• CPC Class Codes: B01D 39/1623 of synthetic origin
• CPC Class Codes: D04H 1/559 the fibres being within layered webs
• CPC Class Codes: D04H 1/56 in association with fibre formation, e.g. immediately following extrusion of staple fibres
• CPC Class Codes: Y10S 428/903 Microfiber, less than 100 micron diameter
• CPC Class Codes: Y10T 442/62 Including another chemically different microfiber in a separate layer
• CPC Class Codes: Y10T 442/68 Melt-blown nonwoven fabric

Abstract

A heat-stable melt-blown web of multi-layer microfibers comprising at least two layers of a heat-stable melt-blowable material and at least one included layer of a second material.

Claims

1. A nonwoven web comprised of melt-blown microfibers, each of said microfibers having at least three substantially continuous and coplanar layers throughout said microfiber length, the at least three layers comprised of at least two first layers of a temperature stable material capable of forming a nonwoven web stable at temperatures above about 130°

C. and at least one second layer of a lower softening point material having a melting point greater than 30°

C. less than the first layer material, wherein at least two first layers surround at least one second layer.

2. The nonwoven web of claim 1 wherein the web exhibits storage modulus values of greater than 10⁶ Pa at temperatures in excess of 150°

C.

3. The nonwoven web of claim 1 wherein the temperature stable material comprises a polyester and the second layer material comprises a polyolefin.

4. The nonwoven web of claim 1 wherein the temperature stable material comprises of polyalkylsulfide and the second layer material comprises of polyolefin.

5. The nonwoven web of claim 1 wherein the average fiber diameter is less than 10 micrometers.

6. The nonwoven web of claim 1 wherein the temperature-stable material has a melt temperature of greater than 150°

C.

7. The nonwoven web of claim 1 wherein the temperature-stable material has a melt temperature of greater than 180°

C.

8. The nonwoven web of claim 2 wherein the storage modulus values are greater than 10⁶ Pa at temperatures in excess of 200°

C.

9. The nonwoven web of claim 8 wherein the storage modulus values are greater than 10⁶ Pa at temperatures in excess of 240°

C.