Method for preparing thermochromic water-based gel ink compositions, and thermochromic water-based gel ink compositions thereof

Patent metadata

Field	Value
Publication number	US-11920047-B2
Application number	US-202117997497-A
Country	US
Kind code	B2
Filing date	Apr 28, 2021
Priority date	Apr 30, 2020
Publication date	Mar 5, 2024
Grant date	Mar 5, 2024

Abstract

A method for preparing a thermochromic water-based gel ink composition, as well as a thermochromic water-based gel ink composition thereof comprising a specific monocarboxylic or polycarboxylic acid. A writing instrument, such as a ballpoint pen, a brush pen, a marker, a highlighter, and a felt pen, comprising a thermochromic water-based gel ink composition according to the disclosure.

First claim

The invention claimed is:

1. A method for preparing a thermochromic water-based gel ink composition comprising the steps of:
(i) preparing a thermochromic pigment composition by mixing:
(A) at least one electron-donating color-developing organic compound,
(B) at least one electron-accepting compound, and
(C) at least one color change temperature regulator,

(ii) encapsulating the thermochromic pigment composition prepared in step (i) in presence of a copolymer surfactant comprising at least one monomer of maleic anhydride, to generate an aqueous suspension of thermochromic pigment microcapsules,
(iii) acidifying the aqueous suspension of thermochromic pigment microcapsules obtained in step (ii) at a pH lower than or equal to 4.6, by adding a monocarboxylic or polycarboxylic acid,
(iv) preparing a thermochromic water-based gel ink composition comprising the aqueous suspension of thermochromic pigment microcapsules obtained in step (iii) and at least a gelling agent.

2. A method as claimed in claim 1 , wherein the copolymer surfactant is chosen from the group consisting of copolymers of maleic anhydride.

3. A method as claimed in claim 1 or claim 2 , wherein the monocarboxylic or polycarboxylic acid is non-polymeric and/or wherein the monocarboxylic or polycarboxylic acid comprises from 2 to 10 carbon atoms.

4. A method as claimed in claim 1 , wherein the encapsulating step (ii) is performed by adding an amino resin to the thermochromic pigment composition prepared in step (i) and the copolymer surfactant.

5. A method as claimed in claim 1 , wherein the monocarboxylic or polycarboxylic acid is chosen from the group consisting of gallic acid, succinic acid, itaconic acid, glutaric acid, oxalic acid, oxaloacetic acid, pyruvic acid, 2-oxo-glutaric acid, malonic acid, salicylic acid, tartaric acid, lactic acid, citric acid, malic acid, picolinic acid, argininosuccinic acid, 2,4,6-trihydroxybenzoic acid, dihydroxymalic acid, aspartic acid, glutathione, glutamic acid, glutamine, 3-methyl-2-oxovaleric acid, acotinic acid and mixtures thereof.

6. A method as claimed in claim 1 , wherein the amount of monocarboxylic or polycarboxylic acid is ranging from 0.5 to 5% by weight relative to the total weight of the aqueous suspension of thermochromic pigment microcapsules.

7. An aqueous suspension of thermochromic pigment microcapsules comprising:
thermochromic pigment microcapsules encapsulating a thermochromic pigment composition comprising:
(A) at least one electron-donating color-developing organic compound,
(B) at least one electron-accepting compound, and
(C) at least one color change temperature regulator,

a monocarboxylic or polycarboxylic acid,
a copolymer surfactant comprising at least one monomer of maleic anhydride,
water
the aqueous suspension of thermochromic pigment microcapsules having a pH lower than or equal to 4.6.

8. An aqueous suspension of thermochromic pigment microcapsules as claimed in claim 7 , wherein the monocarboxylic or polycarboxylic acid is non-polymeric and/or wherein the monocarboxylic or polycarboxylic acid comprises from 2 to 10 carbon atoms.

9. A thermochromic water-based gel ink composition comprising:
thermochromic pigment microcapsules encapsulating a thermochromic pigment composition comprising:
(A) at least one electron-donating color-developing organic compound,
(B) at least one electron-accepting compound, and
(C) at least one color change temperature regulator,
a monocarboxylic or polycarboxylic acid,
a carrier,
a gelling agent, and
a copolymer surfactant comprising at least one monomer of maleic anhydride.

10. A thermochromic water-based gel ink composition as claimed in claim 9 , wherein the electron-donating color-developing organic compound (A) is chosen from the group consisting of 3-(4-diethylamino-2-ethoxyphenyl)-3-(1-ethyl-2-methylindol-3-yl)-4-azaphthalide (Blue 63, CAS number: 69898-40-4), 2′-(dibenzylamino)-6′-(diethylamino)fluoran (CAS number: 34372-72-0), N,N-dimethyl-4-[2-[2-(octyloxy)phenyl]-6-phenyl-4-pyridinyl]benzenamine (Yellow CK37, CAS number: 144190-25-0), 7-(4-diethylamino-2-hexyloxyphenyl)-7-(1-ethyl-2-methyl-1H-indol-3-yl) -7H-furo[3,4-b]pyridin-5-one (Blue 203, CAS number: 98660-18-5), 2-(2,4-dimethylphenylamino)-3-methyl-6-diethylaminofluoran (Black 15, CAS number: 36431-22-8), 3,3-bis-(1-butyl-2-methyl-indol-3-yl)-3H-isobenzofuran-1-one (Red 40, CAS number: 50292-91-6), and mixtures thereof.

11. A thermochromic water-based gel ink composition as claimed in claim 9 , wherein the electron-accepting compound (B) is chosen from the group consisting of 2,2-bis(4-hydroxy-3-methylphenyl)propane (bisphenol C, CAS number: 79-97-0), 4-hexyl-1,3-dihydroxybenzene (4-hexylresorcinol, CAS number: 136-77-6), 4,4′-cyclohexylidenebisphenol (BPZ, CAS number: 843-55-0), 4,4′-(hexafluoroisopropylidene)diphenol (bisphenol AF, CAS number: 1478-61-1), 4,4′-(1-phenylethylidene)bisphenol (CAS number: 1571-75-1), 2,2′-dihydroxybiphenyl (CAS number: 1806-29-7), 4,4′-(1,4-phenylenediisopropylidene)bisphenol (CAS number: 2167-51-3), 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane (CAS number: 2362-14-3), 9,9-bis(4-hydroxyphenyl)fluorene (CAS number: 3236-71-3), 4,4′-(1,3-phenylenediisopropylidene)bisphenol (CAS number: 13595-25-0), 1,1,1-tris(4-hydroxyphenyl)ethane (CAS number: 27955-94-8), 4,4′-(2-ethylhexylidene)diphenol (CAS number: 74462-02-5), α,α,α′-tris(4-hydroxyphenyl)-1-ethyl-4-isopropylbenzene (CAS number: 110726-28-8), and mixtures thereof.

12. A thermochromic water-based gel ink composition as claimed in claim 9 , wherein the color change temperature regulator (C) is chosen from the group consisting of waxes having a melting point ranging from 40 to 80° C.

13. A thermochromic water-based gel ink composition as claimed in claim 9 , wherein the thermochromic pigment microcapsules are present in an amount ranging from 10 to 35%, by weight relative to the total weight of the thermochromic ink composition.

14. A thermochromic water-based gel ink composition as claimed in claim 9 , wherein the monocarboxylic or polycarboxylic acid is non-polymeric and/or wherein the monocarboxylic or polycarboxylic acid comprises from 2 to 10 carbon atoms.

15. A thermochromic water-based gel ink composition as claimed in claim 9 , wherein the monocarboxylic or polycarboxylic acid is present in an amount ranging from 0.2 to 5%.

16. A thermochromic water-based gel ink composition as claimed in claim 9 , wherein the gelling agent is chosen from the group consisting of xanthan gum, sodium alginate, sodium carboxymethyl cellulose, gellan gum, tragacanth gum, and diutan gum.

17. A thermochromic water-based gel ink composition as claimed in claim 9 , comprising one or more adjuvants chosen from the group consisting of rheology modifiers, antimicrobial agents, corrosion inhibitors, antifoam agents, and mixtures thereof.

18. A writing instrument comprising:
an ink reservoir containing a thermochromic water-based gel ink composition as claimed in claim 9 , and
a pen body which delivers the thermochromic water-based gel ink composition stored in the ink reservoir.

19. A thermochromic water-based gel ink composition as claimed in claim 9 , wherein the monocarboxylic or polycarboxylic acid is chosen from the group consisting of gallic acid, succinic acid, itaconic acid, glutaric acid, oxalic acid, oxaloacetic acid, pyruvic acid, 2-oxo-glutaric acid, malonic acid, salicylic acid, tartaric acid, lactic acid, citric acid, malic acid, picolinic acid, argininosuccinic acid, 2,4,6-trihydroxybenzoic acid, dihydroxy

Assignees

• SOCIéTé BIC

Inventors

• Bourque Alexander
• Sauvage Aurore

Classifications

• C09D11/50 Primary

  Sympathetic, colour changing or similar inks · CPC title

• C09D11/17

  characterised by colouring agents · CPC title

• B43K7/00

  Ball-point pens ({B43M11/085 takes precedence}; multiple-point writing implements B43K27/00) · CPC title

• B43K8/024

  with writing-points comprising felt · CPC title

• C09D11/16 Primary

  Writing inks · CPC title