Method of making transparent film from multilayer blown microfibers

• US 5,248,455 A
• Filed: 02/19/1993
• Issued: 09/28/1993
• Est. Priority Date: 09/30/1991
• Status: Expired due to Term

• Current Assignee: 3M Company
• Original Assignee: 3M Company
• Inventors: Joseph, Eugene G., Rustad, James A.
• Primary Examiner(s): THEISEN, MARY LYNN F
• Application Number:
  US08/020,132
• Time in Patent Office: 221 Days
• Field of Search: 264/6, 264/12, 264/115, 264/119, 156/167
• US Class Current: 264/6
• CPC Class Codes: D01D 5/0985 by means of a flowing gas (e.g. melt-blowing)
• 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

Abstract

Method of making a transparent film by forming two or more melt streams, combining the melt streams into a multilayer melt stream, extruding the layered melt stream and attenuating with an airstream to form multilayer microfibers, collecting the microfibers as a nonwoven web, and consolidating the web under heat and pressure. At least one of the melt streams is a thermoplastic elastomer and at least one of the melt streams is a thermoplastic material. The transparent web has a generally continuous elastomeric phase with an included array of thermoplastic microfibers.

Claims

1. A method of forming a transparent film comprising;

forming two or more melt streams at least one of which comprises a thermoplastic elastomer and at least one of which comprises thermoplastic material,

combining the melt stream into a multilayer melt stream,

extruding the layered melt stream through an orifice to form multilayered microfibers by an attenuating airstream,

collecting the formed microfibers as a nonwoven web, and

consolidating the web under heat and pressure sufficient to soften the thermoplastic elastomeric film having a generally continuous elastomeric phase and an included array of thermoplastic material microfibers.

2. The method of claim 1 wherein the thermoplastic material microfibers in the consolidated web have an average thickness of less than 10 microns.

3. The method of claim 1 wherein the thermoplastic material microfibers in the consolidated web have an average thickness of less than 1 micron.

4. The method of claim 1 wherein the thermoplastic material microfibers in the consolidated web have an average thickness of less than 0.1 microns.

5. The method of claim 1 wherein the elastomeric phase comprises a polyurethane and the thermoplastic microfibers comprises a polyolefin.