Friction body

Patent metadata

Field	Value
Publication number	US-12240266-B2
Application number	US-202118258128-A
Country	US
Kind code	B2
Filing date	Dec 17, 2021
Priority date	Dec 18, 2020
Publication date	Mar 4, 2025
Grant date	Mar 4, 2025

Abstract

A friction body for discoloring handwriting written with a thermochromic ink with frictional heat, the friction body including a surface portion configured to generate frictional heat when manually rubbed on a porous substrate. The surface portion may have a thermal effusivity of less than about 300 J K −1 m −2 s −1/2 .

First claim

The invention claimed is:

1. A friction body for discoloring handwriting written with a thermochromic ink with frictional heat,
wherein the friction body comprises a surface portion configured to generate frictional heat when manually rubbed on a porous substrate, and
wherein the surface portion has a thermal effusivity of less than about 300 J K −1 m −2 s −1/2 .

2. The friction body of claim 1 , wherein the porous substrate is a paper substrate.

3. The friction body of claim 1 , wherein the thermal effusivity is less than about 250 J K−1 m−2 s−½.

4. The friction body of claim 1 , wherein the surface portion is configured to heat to a surface temperature of between about 40° C. to about 80° C. when pressed onto a 45 g/m2 paper made of 100% chemical pulp and having a brightness of about 83% with a load of about 500 g per about 3 mm2 to about 8 mm2 contact area and pulled across the paper with a constant pull rate of about 50 to about 500 mm/s.

5. The friction body of claim 1 , wherein the friction body comprises a macromolecular matrix having a first thermal conductivity and domains arranged within said macromolecular matrix having a second thermal conductivity which is lower than the first thermal conductivity.

6. The friction body of claim 1 , wherein the friction body comprises a macromolecular matrix and gas-filled pores.

7. The friction body of claim 5 , wherein the macromolecular matrix is plant-based.

8. The friction body of claim 1 , wherein the friction body comprises a plant-based material having a density of less than about 0.40 g/cm−3.

9. The friction body of claim 1 , wherein the friction body comprises a bark material.

10. The friction body of claim 9 , wherein the friction body comprises natural cork.

11. The friction body of claim 9 , wherein the friction body comprises a lignin-containing material.

12. The friction body of claim 1 , wherein the surface portion has a kinetic coefficient of friction of between about 0.20 and about 0.90, when a specimen of the friction body comprising at least a part of said surface portion is pressed onto a 45 g/m2 paper made of 100% chemical pulp and having a brightness of about 83% with a load of about 500 g per about 3 mm2 to about 8 mm2 contact area contact area and pulled across the paper with a constant pull rate of about 1.6 mm/s.

13. The friction body of claim 1 , wherein at least the surface portion of the friction body has a Shore A hardness of between about 50 to about 90.

14. The friction body of claim 1 , wherein at least the surface portion of the friction body has a thermal conductivity of less than 0.05 W/(m·K).

15. The friction body of claim 1 , wherein the friction body has a Young's modulus of less than about less than about 35 MPa.

16. The friction body of claim 1 , wherein the friction body has a specific heat capacity of at least about 1300 J·kg−1·K−1.

17. A writing instrument comprising a writing tip, a storage compartment comprising a thermochromic ink which is in fluid communication with the writing tip, and a friction body as defined in claim 1 ; optionally wherein the friction body is positioned at an end of the writing instrument opposite to the writing tip or wherein the writing instrument comprises a cap for capping the writing tip which comprises the friction body.

18. The writing instrument of claim 17 , wherein the thermochromic ink is configured to change its color or discolor when heated to a temperature of between about 40° C. to about 80° C.

19. A friction body for discoloring handwriting written with a thermochromic ink with frictional heat, wherein the friction body comprises a first surface portion comprising bark material, and wherein the friction body comprises a second surface portion comprising natural cork.

Assignees

• SOCIéTé BIC

Inventors

• Oger Myriam

Classifications

• B43K29/02 Primary

  with rubbers · CPC title

• B43L19/0025 Primary

  Eraser or rubber material, e.g. comprising hard particles · CPC title