FIBRILLATION METHOD

• US 3,596,816 A
• Filed: 05/05/1969
• Issued: 08/03/1971
• Est. Priority Date: 05/05/1969
• Status: Expired due to Term

• Current Assignee: Claude V. Brown
• Original Assignee: Claude V. Brown
• Inventors: Brown, Claude V.
• Application Number:
  US04/821,856
• Time in Patent Office: 820 Days
• US Class Current: 225/2
• CPC Class Codes: D01D 5/423 by fibrillation of films or filaments
• CPC Class Codes: Y10S 264/47 Processes of splitting film, webs or sheets
• CPC Class Codes: Y10T 225/12 With preliminary weakening
• CPC Class Codes: Y10T 225/14 Longitudinally of direction of feed
• CPC Class Codes: Y10T 225/321 Preliminary weakener

Abstract

A method for fibrillating an oriented film or thermoplastic material. The method includes forming elongate lines of weakness in the film and mechanically working the weakened film to promote the splitting up along the lines of weakness.

Claims

1. A method for fibrillating an oriented film of thermoplastic material comprising the steps of:

mechanically forming elongated lines of weakness in said film according to a predetermined pattern, said lines of weakness extending substantially parallel to the direction of orientation with each of said lines of weakness comprising at least one indention line on a surface of the film;

forming elongated slits through the film with each slit abutting at least one of the lines of indention of the film; and

applying a stress to said film having elongated lines of weakness and splitting the film along said lines thereby forming uniformly fibrillated material.

2. The method as recited in claim 1 wherein said thermoplastic material is composed of a polymer of 1-olefins, and said film is prepared by a water-quenching technique.

3. The method as recited in claim 2 wherein said polymer is polypropylene and the orientation of said water-quenched film of polypropylene is about 5:

1 or less.

4. A method, as set forth in claim 1, wherein the film prior to stressing has a pluralIty of lines of weakness each having a length of at least 50 mils.

5. A method for fibrillating an oriented film of thermoplastic material comprising:

mechanically forming elongated lines of weakness in said film according to a preselected pattern, said lines of weakness extending substantially parallel to the direction of orientation with each of said lines of weakness comprising at least one indention line on a surface of the film; and

applying a stress to said film having elongated lines of weakness in a direction transverse the direction of orientation with said stress being applied by frictionally working the film by oscillating the film in a direction transverse the direction of orientation of the film.

6. The method as recited in claim 5 wherein said thermoplastic material is composed of a polymer of 1-olefins, and said film is prepared by a water-quenching technique.

7. The method as recited in claim 6 wherein said polymer is polypropylene and the orientation of said water-quenched film of polypropylene is about 5:

1 or less.

8. A method, as set forth in claim 5, wherein the film prior to stressing has a plurality of lines of weakness each having a length of at least 50 mils.