Process for making filament having unique tip and surface characteristics

Patent metadata

Field	Value
Publication number	US-9340903-B2
Application number	US-201414301716-A
Country	US
Kind code	B2
Filing date	Jun 11, 2014
Priority date	Jun 11, 2014
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

A process for making a filament for use in a brush implement comprises providing a composite filament comprising an external material and at least one internal material, wherein the tip surface comprises the internal material surrounded by the external material, the internal material having longitudinal shrinkage characteristics that differ from those of the external material; and causing the internal material to shrink inside the external material, whereby the internal material comprising the tip surface sinks relative to the external material comprising the tip surface so that at least one crater is formed at the tip surface of the filament, the at least one crater comprising a bottom formed by the internal material and walls formed by the external material, the at least one crater having a surface edge of a predetermined size and a predetermined shape.

First claim

What is claimed is:

1. A process for making a filament having at least one crater at a tip surface of at least one free end of the filament, the process comprising:
providing a composite filament comprising an external material and an internal material, wherein the tip surface comprises the internal material surrounded by the external material, the internal material having longitudinal shrinkage characteristics that differ from those of the external material;
causing the internal material to shrink inside the external material, whereby the internal material comprising the tip surface sinks relative to the external material comprising the tip surface so that at least one crater is formed at the tip surface of the filament, wherein the at least one crater comprises a bottom formed by the internal material and walls formed by the external material, and wherein the at least one crater has a surface edge of a predetermined size and a predetermined shape.

2. The process of claim 1 , wherein providing a composite filament comprises providing the filament in which the external material differs from the internal material in at least one physical property selected from the group consisting of color, elasticity, density, hardness, surface energy, heat-shrinkage rate, longitudinal anisotropic-shrinkage rate, isotropic-shrinkage rate, bending-shrinkage rate, and any combination thereof.

3. The process of claim 1 , wherein providing a filament comprises providing a filament having the internal material that comprises a plurality of strands extending inside the filament along the longitudinal axis thereof and separated from one another by the external material, and wherein the at least one crater comprises a plurality of craters.

4. The process of claim 1 , wherein the process comprises extruding a continuous filament and cutting the continuous filament into a plurality of filaments of predetermined length.

5. The process of claim 1 , wherein the process comprises profiling the tip surface of the filament.

6. The process of claim 1 , wherein profiling the tip surface of the filament comprises causing the tip of the filament to acquire, at least partially, a shape selected from the group consisting of a concave shape, a convex shape, a planar shape, and any combination thereof.

7. The process of claim 1 , wherein causing the internal material to shrink inside the external material comprises heating the internal material to a first temperature and then cooling the internal material to a second temperature, wherein the first temperature is a temperature between the glass-transition temperature and the melting temperature of the internal material, and the second temperature is a room temperature.

8. The process of claim 7 , wherein the first temperature is from 90° C. to 140° C.

9. The process of claim 7 , wherein the second temperature is from 15° C. to 25° C.

10. The process of claim 1 , wherein causing the internal material to shrink inside the external material comprises causing the filament to repeatedly bend multiple times and in multiple directions.

11. The process of claim 1 , wherein causing the internal material to shrink inside the external material comprises causing the filament to be repeatedly brushed against a surface.

12. The process of claim 1 , the process comprising preventing the internal material from moving relative to the external material inside the filament at a location removed from the tip surface of the filament.

13. The process of claim 12 , wherein preventing the internal material from moving relative to the external material inside the filament at a location removed from the tip surface of the filament comprises affixing a portion of the filament at the location removed from the tip surface to a body of an oral-care implement.

14. The process of claim 13 , wherein affixing a portion of the filament to a body of an oral-care implement comprises a method selected from the group consisting of stapling, overmolding, hot tufting, and any combination thereof.

15. The process of claim 1 , wherein profiling the tip surface of the filament occurs prior to causing the internal material to shrink inside the external material.

16. The process of claim 1 , wherein preventing the internal material from moving relative to the external material inside the filament occurs prior to causing the internal material to shrink inside the external material.

17. The process of claim 1 , wherein causing the internal material to shrink inside the external material results in the at least one crater having the walls substantially parallel to the longitudinal axis of the filament.

18. The process of claim 1 , wherein causing the internal material to shrink inside the external material results in the at least one crater comprising the surface edge having the curvature radius of less than 5 μm.

19. The process of claim 1 , wherein causing the internal material to shrink inside the external material results in the at least one crater comprising the surface edge having the curvature radius of less than 3 μm.

20. A process for making an oral-care implement comprising a plurality of cleaning elements, wherein at least some of the cleaning elements comprise composite filaments having a plurality of craters at tip surfaces of free ends of the filaments, the process comprising:
providing a plurality of composite filaments, each composite filament comprising an external material and an internal material, wherein the tip surface comprises the internal material surrounded by the external material, the internal material having longitudinal shrinkage characteristics that differ from those of the external material;
affixing the plurality of composite filaments to a body of the oral-care implement;
profiling the tip surfaces of the plurality of composite filaments according to a predetermined pattern; and
causing the internal material to shrink inside the external material in the composite filaments, whereby the internal material comprising the tip surfaces sinks relative to the external material comprising the tip surface so that the plurality of craters is formed at the tip surfaces of the composite filaments, the craters having surface edges comprising the external material, bottoms comprising the internal material, and walls extending between the edges and the bottoms and comprising the external material.

Assignees

• Procter & Gamble
• Procter & Gamble

Inventors

• Chan John Geoffrey
• Wen Li
• Reno Elizabeth Ann Brown
• Carson John Kit
• Mao Xiaole

Classifications

• A46B2200/1066

  Toothbrush for cleaning the teeth or dentures (A61C17/16 takes precedence; bristles arrangements for toothbrushes A46B9/04) · CPC title

• D01D10/02 Primary

  Heat treatment (heating for finishing D02J13/00) · CPC title

• A46D3/00

  Preparing, {i.e. Manufacturing} brush bodies · CPC title

• D01D5/34

  Core-skin structure; Spinnerette packs therefor · CPC title

• A46D1/0246

  Hollow bristles · CPC title