Method for producing a toothbrush having an inner cavity

Patent metadata

Field	Value
Publication number	US-9756931-B2
Application number	US-201213683744-A
Country	US
Kind code	B2
Filing date	Nov 21, 2012
Priority date	Nov 22, 2011
Publication date	Sep 12, 2017
Grant date	Sep 12, 2017

Abstract

Methods for producing toothbrush handles having an inner cavity are provided.

First claim

What is claimed is:

1. A method for extrusion blow molding a toothbrush comprising:
a) providing an extrusion blow mold having a longitudinal axis and a cavity, the cavity having a handle portion, a neck portion, a head portion, and a surface that defines a cross-sectional area; wherein the cavity has at least one of a maximum cross-sectional area, bordered by two smaller cross-sectional areas along the longitudinal axis of the blow mold or a minimum cross sectional area bordered by two greater cross-sectional areas along the longitudinal axis of the blow mold;
b) providing a subassembly positioned in the head portion of the cavity;
c) extruding a parison comprising a thermoplastic material, the parison includes an interior cavity and an outer surface, wherein the outer surface defines a cross-sectional area of the parison;
d) expanding the parison using a fluid to contact the cavity surface and subassembly to produce a toothbrush handle having an inner cavity.

2. The method of claim 1 , wherein the subassembly comprises a front surface and a parison contacting surface.

3. The method of claim 2 , wherein the parison contacting surface of the subassembly has a convex shape.

4. The method of claim 1 , wherein the subassembly comprises at least one cleaning element extending from the front surface.

5. The method of claim 4 , wherein the at least one cleaning element extends into a recess positioned in the head portion of the cavity.

6. The method of claim 1 , wherein the parison and subassembly comprise the same thermoplastic material.

7. The method of claim 1 , wherein the subassembly comprises a mechanical feature.

8. The method of claim 1 , wherein the minimum cross-sectional area of the extrusion blow mold cavity is less than the cross-sectional area of the parison.

9. The method of claim 1 , wherein the maximum cross-sectional area of the extrusion blow mold cavity is greater than the cross-sectional area of the parison.

10. The method of claim 1 , wherein the extrusion blow mold includes a label prior to extrusion of the parison.

11. A toothbrush produced by the method of claim 1 comprising:
a) a head, neck, handle, handle end, head end, outer surface, inner cavity, and longitudinal axis;
b) the inner cavity having a surface defining a cross-sectional area; wherein the inner cavity has at least one of a greater cross-sectional area, bordered by two lesser cross-sectional areas along the longitudinal axis of the toothbrush or a lesser cross sectional area bordered by two greater cross-sectional areas along the longitudinal axis of the toothbrush;
c) the outer surface defining an outer surface cross-sectional area;
d) a wall formed from the outer cavity surface and inner cavity surface;
e) a subassembly positioned in the head;

wherein the toothbrush comprising a single unitary component.

12. The toothbrush of claim 11 , wherein the square root of the outer surface cross-sectional area varies proportionally to the square root of the inner cavity cross-sectional area along the longitudinal axis of the toothbrush.

13. The toothbrush of claim 12 , wherein the square root of the inner cavity surface cross-sectional area varies proportionally less than 5% to the variations in the square root of the outer surface cross-sectional area along the longitudinal axis of the toothbrush handle.

14. The toothbrush of claim 11 , wherein the in the thickness of the toothbrush handle wall varies in inverse proportion to the square root of the outer surface cross-sectional area.

15. The toothbrush of claim 11 having a specific gravity below about 0.60 g/cm 3 and wherein the toothbrush handle deforms less than about 20 mm under a 5.0N force applied as determined by ASTM D 790.

16. A method for extrusion blow molding a toothbrush comprising:
a) providing an extrusion blow mold having a longitudinal axis and a cavity, the cavity having a handle portion, a neck portion, a head portion, and a surface that defines a cross-sectional area; wherein the cavity has at least one of a maximum cross-sectional area, bordered by two smaller cross-sectional areas along the longitudinal axis of the blow mold or a minimum cross sectional area bordered by two greater cross-sectional areas along the longitudinal axis of the blow mold;
b) providing a subassembly positioned in the head portion of the cavity;
c) extruding a parison comprising a first thermoplastic material and a second thermoplastic material, the parison includes an interior cavity and an outer surface, wherein the outer surface defines a cross-sectional area of the parison;
d) expanding the parison using a fluid to contact the cavity surface and subassembly to produce a toothbrush handle having an inner cavity.

17. The method of claim 16 , wherein the first material forms an inner layer and the second thermoplastic material forms an outer layer.

18. The method of claim 16 , wherein the first thermoplastic material and the second thermoplastic material form a single layer.

19. A toothbrush produced by the method of claim 16 comprising:
a) a head, neck, handle, handle end, head end, outer surface, inner cavity, and longitudinal axis;
b) the inner cavity having a surface defining a cross-sectional area; wherein the inner cavity has at least one of a greater cross-sectional area, bordered by two lesser cross-sectional areas along the longitudinal axis of the toothbrush or a lesser cross sectional area bordered by two greater cross-sectional areas along the longitudinal axis of the toothbrush;
c) the outer surface defining an outer surface cross-sectional area;
d) a wall formed from the outer cavity surface and inner cavity surface;
e) a subassembly positioned in the head;

wherein the toothbrush comprising a single unitary component.

20. The toothbrush of claim 19 , wherein the square root of the outer surface cross-sectional area varies proportionally to the square root of the inner cavity cross-sectional area along the longitudinal axis of the toothbrush.

Assignees

• Procter & Gamble

Inventors

• Newman Matthew Lloyd
• Wen Li
• Houghton Stephen Alan
• Jackson Scott
• Phillips Bradley John
• Satterfield Richard Darren
• Uhe Andrew M
• Ryan Christopher Thomas

Classifications

• B29C49/04112

  for varying the thickness · CPC title

• B29C49/20

  of articles having inserts or reinforcements {; Handling of inserts or reinforcements} · CPC title

• A46D3/005 Primary

  by moulding or casting a body around bristles or tufts of bristles · CPC title

• A46B2200/1066

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

• B29L2031/425

  Toothbrush · CPC title