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US-12617960-B2 - Washable ink composition

US12617960B2US 12617960 B2US12617960 B2US 12617960B2US-12617960-B2

Abstract

The present invention concerns a washable aqueous ink composition comprising: a) at least one salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon atoms, 5b) at least one salt of polyacrylic acid, c) at least one dye. It also concerns a writing instrument comprising it and the use of the association of a) at least one salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon and b) at least one salt of polyacrylic acid, to improve the washability 10 and/or vividness of the shades of a washable aqueous ink composition.

Inventors

  • Carine Bethouart

Assignees

  • SOCIéTé BIC

Dates

Publication Date
20260505
Application Date
20211004
Priority Date
20201006

Claims (20)

  1. 1 . An aqueous ink composition, comprising: a combination of: at least one salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon atoms, and at least one salt of polyacrylic acid; and at least one water soluble dye, wherein the aqueous ink composition is washable.
  2. 2 . The aqueous ink composition according to claim 1 , wherein the at least one salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon atoms is a salt of monocarboxylic acid with from 3 to 8 carbon atoms, dicarboxylic acid with from 3 to 8 carbon atoms, or tricarboxylic acid with from 3 to 8 carbon atoms or mixture thereof.
  3. 3 . The aqueous ink composition according to claim 1 , wherein the at least one salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon atoms is selected from the group consisting of salts of gluconic acid, salts of citric acid, and a mixture thereof.
  4. 4 . The aqueous ink composition according to claim 1 , wherein the at least one salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon atoms is selected from the group consisting of sodium citrate, sodium gluconate, and a mixture thereof.
  5. 5 . The aqueous ink composition according to claim 1 , wherein the at least one salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon atoms is an alkali metal salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon atoms.
  6. 6 . The aqueous ink composition according to claim 1 , wherein a total amount of the at least one salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon atoms in the aqueous ink composition ranges from 0.5 wt. % to 30 wt. %, based on a total weight of the aqueous ink composition.
  7. 7 . The aqueous ink composition according to claim 1 , wherein the at least one salt of polyacrylic acid is an alkali metal salt of polyacrylic acid.
  8. 8 . The aqueous ink composition according to claim 1 , wherein the at least one salt of polyacrylic acid includes sodium polyacrylate.
  9. 9 . The aqueous ink composition according to claim 1 , wherein a total amount of the at least one salt of polyacrylic acid in the aqueous ink composition ranges from 0.2 wt. % to 15 wt. %, based on a total weight of the aqueous ink composition.
  10. 10 . The aqueous ink composition according to claim 1 , wherein the at least one water soluble dye comprises an acid dye.
  11. 11 . The aqueous ink composition according to claim 1 , wherein a total amount of the at least one water soluble dye in the aqueous ink composition ranges from 0.01 wt. % to 20 wt. %, based on a total weight of the aqueous ink composition.
  12. 12 . The aqueous ink composition according to claim 1 , further comprising at least one humectant.
  13. 13 . The aqueous ink composition according to claim 12 , wherein the at least one humectant includes a water-soluble alcohol having a melting point of less than 20° C. and a boiling point of at least 150° C.
  14. 14 . The aqueous ink composition according to claim 12 , wherein the at least one humectant is selected from the group consisting of glycerin, ethylene glycol, sorbitol, diethylene glycol, triethylene glycol, propylene glycol, thiodiglycol, and mixtures thereof.
  15. 15 . The aqueous ink composition according to claim 12 , wherein a total amount of the at least one humectant in the aqueous ink composition ranges from 1 wt. % to 50 wt. %, based on a total weight of the aqueous ink composition.
  16. 16 . The aqueous ink composition according to claim 1 , further comprising an additive.
  17. 17 . The aqueous ink composition according to claim 1 , wherein a total amount of water in the aqueous ink composition ranges from 20 wt. % to 95 wt. %, based on a total weight of the aqueous ink composition.
  18. 18 . A writing instrument comprising the aqueous ink composition as claimed in claim 1 .
  19. 19 . The aqueous ink composition according to claim 1 , wherein an average molar mass of the at least one salt of polyacrylic acid ranges from 500 g/mol to 300,000 g/mol.
  20. 20 . The aqueous ink composition according to claim 1 , wherein a weight ratio of the at least one salt of salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon atoms to the at least one salt of polyacrylic acid ranges from 0.1:1 to 100:1.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a National Stage Application of International Application No. PCT/EP2021/077285, filed on Oct. 4, 2021, now published as WO2022/073925A1 and which claims priority to European Application No. 20306159.3, filed on Oct. 6, 2020, the entire contents of which is incorporated herein by reference. TECHNICAL FIELD The present disclosure concerns washable/rinseable ink compositions, more specifically aqueous washable ink compositions. Existing washable ink compositions contain «conventional» dyes which are often acid dyes, soluble in water. These dyes can be Food dyestuffs or if not, these dyes must be in conformity with the Toy's Regulation in place if the products are dedicated to children. The word “washable” means that stains may be removed from common washable fabrics after 1 to 3 washes at 40° C. following ISO 6330:2012 standard. The “washable” inks contain generally glycol in order to manage surface tension of the inks and to limit the drying of the nib in case the cap of the marker or felt pen is off. The dyes used have generally a “substantive” character, the size of the dye molecules is so small and the surface tension of the ink is usually low that the stains are difficult to remove from the substrate, mainly on the skin. There is a penetration of the dye molecules into the porosity of the surface. Existing washable ink formulations having better washability requirements and more specifically whose stains may be removed from the skin with tepid water and soap, contains specific dyes which are often polymeric dyes. These dyes are not Food dyestuffs but these dyes must be in conformity with the Toy's Regulation in place if the products are dedicated to children. These inks are usually much more expensive and the shades obtained with the polymeric dyes are generally less vivid than the ones obtained with conventional Acid dyes. SUMMARY The aim of the disclosure is to formulate washable inks having better washability requirements, more specifically being washable from the skin even with cold water, and containing “conventional dyes” such as acid dyes in order to have more vivid color. More specifically the inventors have found that there was a synergy in the combined used of a salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon atoms and a salt of polyacrylic acid. Indeed this combination improves the skin washability of the ink, more specifically with water, even more specifically without using soap, even more specifically using cold water. Moreover acid dyes could be used with this combination in the washable ink, which provides vivid color to the ink. DETAILED DESCRIPTION The present disclosure therefore concerns a washable aqueous ink composition comprising: a) at least one salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon atoms, more specifically an alkali metal salt of monocarboxylic or polycarboxylic acid with from 3 to 8 carbon atoms, and even more specifically wherein the alkali metal salt is sodium,b) at least one salt of polyacrylic acid, specifically an alkali metal salt of polyacrylic acid, more specifically sodium polyacrylate,c) at least one dye. Hereinafter, a detailed description of the present disclosure will be given. The specific embodiments are meant to better illustrate the present disclosure, however, it should be understood that the present disclosure is not limited to these specific embodiments. In the sense of the present disclosure, the expression “comprising a” should be understood as being synonymous with “comprising at least one”. In the sense of the present disclosure, the expressions “between . . . and . . . ” or “ranging from . . . to . . . ” should be understood as including the values of the limits. As indicated above, in the sense of the present disclosure, “a washable ink” is intended to mean any ink, the stains of which may be removed from common washable fabrics after 1 to 3 washes at 40° C. following ISO 6330:2012 standard. More specifically, the washable ink composition according to the present disclosure is a writing ink. For the purposes of the present disclosure, the term “writing ink” is intended to mean any ink which is intended to be used in a writing instrument, and more specifically in a felt-pen, a highlighter, a roller pen or a marker. A writing ink should not be confused with a printing ink which is used in printing machines and which does not have the same technical constraints, and thus the same specifications. Indeed, a writing ink must not contain solid particles of which the size is greater than the channels of the writing instrument, in order to avoid blocking them, which would inevitably lead to writing being irreversibly stopped. It must also dry sufficiently rapidly to avoid smudging the writing medium. It must also avoid the problems of migration (bleeding) over time. Thus, the writing ink composition according to the present disclosure will be suitabl