阅读说明：本技术 用于制备具有可变颜色的水性凝胶油墨的方法和其水性凝胶油墨 (Method for preparing aqueous gel ink with variable color and aqueous gel ink thereof ) 是由 K·穆金 F·吉拉尔 A·斯潘根伯格 R·梅蒂隆 O·奥尔本 于 2019-11-18 设计创作，主要内容包括：本发明涉及一种用于原位制备具有可变颜色的水性凝胶油墨的方法,所述方法包括以下步骤：(i)制备包括还原剂的基于凝胶的水性油墨基质,(ii)加入金属盐溶液,(iii)加入铁粉以获得具有可变颜色的水性凝胶油墨,其中步骤(ii)和(iii)可以互换。本发明还涉及一种根据本发明的方法获得的具有可变颜色的水性凝胶油墨,所述水性凝胶油墨包括还原剂、金属纳米颗粒和铁粉。最后,本发明涉及一种书写工具,所述书写工具包括根据本发明的具有可变颜色的水性凝胶油墨。(The present invention relates to a method for the in situ preparation of an aqueous gel ink with variable colour, comprising the steps of: (i) preparing a gel-based aqueous ink base comprising a reducing agent, (ii) adding a metal salt solution, (iii) adding iron powder to obtain an aqueous gel ink having a variable color, wherein steps (ii) and (iii) are interchangeable. The invention also relates to an aqueous gel ink with variable colour obtained according to the method of the invention, comprising a reducing agent, metal nanoparticles and iron powder. Finally, the invention relates to a writing instrument comprising the aqueous gel ink with variable colour according to the invention.)

1. A method for the in situ preparation of an aqueous gel ink having a variable color, the method comprising the steps of:

(i) preparing a gel-based aqueous ink base comprising a reducing agent,

(ii) adding a metal salt solution into the mixture,

(iii) iron powder is added to obtain an aqueous gel ink with variable colour,

wherein steps (ii) and (iii) are interchangeable.

2. The method of claim 1, wherein the reducing agent is selected from the group consisting of hydroxylamine, ascorbic acid, and mixtures thereof.

3. The method of claim 1 or claim 2, wherein the concentration of reducing agent in the gel-based aqueous ink base of step (i) ranges from 0.01mol^-1To 0.3mol.L^-1。

4. The method of any one of claims 1 to 3, wherein the metal salt solution is a gold salt (Au)³⁺) Silver salt (Ag)⁺) And mixtures thereof.

5. The method of any one of claims 1 to 4, wherein the concentration of metal salt in the gel-based aqueous ink base of step (ii) is in the range of 0.001mol^-1To 0.1mol.L^-1。

6. An aqueous gel ink with variable colour obtained according to the process of any one of claims 1 to 5, comprising a reducing agent, metal nanoparticles and iron powder.

7. The aqueous gel ink of claim 6, wherein the amount of reducing agent ranges from 0.05 wt% to 5 wt% relative to the total weight of the aqueous gel ink.

8. The aqueous gel ink of claim 6 or claim 7, wherein the metal nanoparticles are selected from the group consisting of gold nanoparticles, silver nanoparticles, and mixtures thereof.

9. The aqueous gel ink according to any one of claims 6 to 8, wherein the average particle size of the metal nanoparticles ranges from 1nm to 100nm, and preferably from 10nm to 60 nm.

10. The aqueous gel ink according to any one of claims 6 to 9, wherein the amount of metal nanoparticles ranges from 0.01 wt% to 1 wt% relative to the total weight of the aqueous gel ink.

11. The aqueous gel ink of any one of claims 6 to 10, wherein the amount of iron powder ranges from 0.0001 wt% to 0.04 wt% relative to the total weight of the aqueous gel ink.

12. The aqueous gel ink of any one of claims 6 to 11, wherein the amount of water ranges from 50 wt% to 95 wt% relative to the total weight of the aqueous gel ink.

13. The aqueous gel ink of any one of claims 6-12, wherein the distance between the metal nanoparticles within the aqueous gel ink is less than 100 nm.

14. The aqueous gel ink according to any one of claims 6 to 13, further comprising a solvent selected from the group consisting of glycol ethers, preferably in an amount ranging from 5 to 30 wt% relative to the total weight of the aqueous gel ink.

15. The aqueous gel ink according to any one of claims 6 to 14, further comprising an antibacterial agent selected from the group consisting of 1, 2-benzisothiazolin-3-one, 2-methyl-4-isothiazolin-3-one, and a mixture thereof, preferably in an amount ranging from 0.01 wt% to 0.5 wt% relative to the total weight of the aqueous gel ink.

16. The aqueous gel ink according to any one of claims 6 to 15, further comprising a corrosion inhibitor selected from the group consisting of methylbenzotriazole (tolytriazole), benzotriazole and mixtures thereof, preferably in an amount ranging from 0.05 to 1 wt% relative to the total weight of the aqueous gel ink.

17. The aqueous gel ink according to any one of claims 6 to 16, further comprising an antifoaming agent, preferably in an amount ranging from 0.05 wt% to 1 wt% relative to the total weight of the aqueous gel ink.

18. The aqueous gel ink according to any one of claims 6 to 17, further comprising a rheology modifier selected from the group consisting of xanthan gum, gum arabic and mixtures thereof, preferably in an amount ranging from 0.08% to 2% by weight relative to the total weight of the aqueous gel ink.

19. A method of writing with an aqueous gel ink having a variable color, the method comprising the step of writing on a medium with the aqueous gel ink having a variable color according to any one of claims 6 to 18.

20. A writing instrument, comprising:

-a mandrel containing an aqueous gel ink with variable colour according to any one of claims 6 to 18, and

-a body delivering the aqueous gel ink stored in the cartridge.

21. The writing instrument of claim 20, selected from the group consisting of gel pens, felt pens, correction fluids, markers, and preferably gel pens.