Reverse photochromic inks, and associated methods and writing instruments

Patent metadata

Field	Value
Publication number	US-2022372321-A1
Application number	US-202017761752-A
Country	US
Kind code	A1
Filing date	Sep 23, 2020
Priority date	Sep 24, 2019
Publication date	Nov 24, 2022
Grant date	—

Abstract

Reverse photochromic ink formulations containing at least one reverse photochromic colorant, methods of erasing reverse photochromic ink formulations by exposing them to UV light, and writing instruments including a writing tip portion connected to a light-shielding tubular member or refill and a reverse photochromic ink formulation are provided herein.

First claim

1 . An ink formulation comprising:
a reverse photochromic colorant; and an activator or bleaching agent.

2 . The ink formulation of claim 1 , wherein the ink formulation contains the reverse photochromic colorant in an amount of from about 20 wt. % to about 100 wt. %.

3 . (canceled)

4 . The ink formulation of claim 1 , further comprising a solvent, wherein the ink formulation contains the solvent in an amount of from about 20 wt. % to about 80 wt. %.

5 . The ink formulation of claim 4 , wherein the solvent comprises an alcohol, wherein the alcohol is benzyl alcohol, ethanol, n-propanol, n-butanol, diacetone alcohol, or a combination thereof.

6 . (canceled)

7 . The ink formulation of claim 1 , further comprising a resin, wherein the ink formulation contains the resin in an amount of from about 10 wt. % to about 50 wt. %, wherein the resin comprises an acrylic resin.

8 - 10 . (canceled)

11 . A method of erasing ink comprising:
disposing an ink formulation comprising a reverse photochromic colorant on a surface; exposing the surface to UV light, wherein the surface is white in color and wherein, after exposing the surface to UV light, the surface has a ΔE* value of from about 40 to about 100, a ΔL* value of from about 1 to about 100, a Δa* value of from about +/−0.1 to about +/−90, a Δb* value of from about +/−0.1 to about +/−90, or any combination thereof.

12 . (canceled)

13 . The method of claim 11 , wherein the UV light comprises 340 nm UV light or 365 nm UV light.

14 . The method of claim 11 , wherein exposing the surface to UV light comprises exposing the surface to a UV light source having an irradiance of, less than 100,000 mW/cm 2 of 340 nm UV light, less than 245,000 mW/cm 2 of 365 nm UV light, or less than 909,000 mW/cm 2 of 400 nm UV light.

15 . The method of claim 11 , wherein exposing the surface to UV light comprises exposing the surface to a 340 nm to 400 nm UV light source having an irradiance of from about 1 mW/cm 2 to about 30 mW/cm 2 for a time period of from about one second to about 5 minutes.

16 - 28 . (canceled)

29 . A method of erasing ink comprising:
disposing an ink formulation comprising a reverse photochromic colorant on a surface; exposing the surface to UV light; and disposing a UV absorbing ink formulation on the reverse photochromic ink formulation disposed on the surface, prior to exposing the surface to UV light, wherein the UV absorbing ink formulation comprises a UV absorber.

30 . The method of claim 29 , wherein the UV absorbing ink formulation contains the UV absorber in an amount of from about 1 wt. % to about 20 wt. %.

31 . The method of claim 29 , wherein the UV absorber comprises 2-hydroxy-benzophenone, oxalanilide, 2-(2-hydroxyphenyl)-benzotriazole, hydroxyphenyl-s-triazine (“HPT”), any derivatives thereof, or any combination thereof.

32 . The method of claim 29 , wherein the UV absorbing ink formulation further comprises a solvent, wherein the UV absorbing ink formulation contains the solvent in an amount of from about 20 wt. % to about 80 wt. %.

33 . (canceled)

34 . The method of claim 29 , wherein the UV absorbing ink formulation further comprises a resin.

35 . The method of claim 34 , wherein the UV absorbing ink formulation contains the resin in an amount of from about 10 wt. % to about 50 wt. %.

36 . The method of claim 29 , wherein the surface is white in color and wherein, after exposing the surface to UV light, the surface has a ΔE* value of less than about 1, a ΔL* value of less than about 0.5, a Δa* value of from about −0.5 to about 0.05, a Δb* value of from about −0.5 to about 0.5, or any combination thereof.

37 . (canceled)

38 . The method of claim 29 , wherein the UV light comprises 340 nm UV light or 365 nm UV light.

39 . The method of claim 29 , wherein exposing the surface to UV light comprises exposing the surface to a UV light source having an irradiance of, less than 100,000 mW/cm 2 of 340 nm UV light, less than 245,000 mW/cm 2 of 365 nm UV light, or less than 909,000 mW/cm 2 of 400 nm UV light.

40 . The method of claim 29 , wherein exposing the surface to UV light comprises exposing the surface to a 340 nm to 400 nm UV light source having an irradiance of from about 1 mW/cm 2 to about 30 mW/cm 2 for a time period of from about one second to about 5 minutes.

41 . (canceled)

Assignees

• Sanford Lp

Inventors

• Czaplewski Kenneth

Classifications

• C09D11/50 Primary

  Sympathetic, colour changing or similar inks · CPC title

• C09D11/17

  characterised by colouring agents · CPC title

• C09D11/18 Primary

  specially adapted for ball-point writing instruments · CPC title