Aqueous formulation comprising low visibility naphthalocyanine dye

• US 7,972,427 B2
• Filed: 10/13/2010
• Issued: 07/05/2011
• Est. Priority Date: 07/10/2006
• Status: Expired due to Fees

• Current Assignee: BASF SE
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Hall, Lachlan Everett, Silverbrook, Kia, Indusegaram, Sutharsiny, Vonwiller, Simone Charlotte, Starling, Scott Matthew, Ridley, Damon Donald, Gonzaga, Graciel
• Primary Examiner(s): KLEMANSKI, HELENE G
• Application Number:
  US12/904,027
• Publication Number:
  US 20110023751A1
• Time in Patent Office: 265 Days
• Field of Search: 106/31.49, 106/31.43
• US Class Current: 106/31.49
• CPC Class Codes: C09B 47/0673 having alkyl radicals linked directly to the Pc skeleton; having carbocyclic groups linked directly to the skeleton
• CPC Class Codes: C09B 47/0678 having-COOH or -SO3H radicals or derivatives thereof directly linked to the skeleton
• CPC Class Codes: C09B 47/26 Amide radicals
• CPC Class Codes: C09B 69/04 of anionic dyes with nitrogen containing compounds
• CPC Class Codes: C09D 11/328 characterised by dyes
• CPC Class Codes: Y10T 428/24802 Discontinuous or differential coating, impregnation or bond [e.g., artwork, printing, retouched photograph, etc.]
• CPC Class Codes: Y10T 428/24934 including paper layer

Abstract

An aqueous formulation comprises a sulfonated water-soluble IR-absorbing naphthalocyanine dye having a central metal atom moiety. A pH of the formulation is in the range of 4 to 6.5, which minimizes visibility of the formulation.

Claims

1. An aqueous formulation comprising a sulfonated water-soluble IR-absorbing naphthalocyanine dye having a central metal atom moiety, wherein a pH of said formulation is in the range of 4 to 6.5 so as to minimize visible coloration of the formulation.

2. The formulation of claim 1, wherein said formulation is buffered.

3. The formulation of claim 1 further comprising at least one base B, wherein a conjugate acid BH⁺ of said at least one base B has a pK_a of between 4 and 9.

4. The formulation of claim 3, wherein a conjugate acid BH⁺ of said at least one base B has a pK_a of between 4.5 and 8.

5. The formulation of claim 3 comprising a nitrogen base, an oxyanion base or mixtures thereof.

6. The formulation of claim 5, wherein said nitrogen base is a nitrogen-containing C_5-12 heteroaryl base.

7. The formulation of claim 6, said nitrogen base is imidazole or pyridine.

8. An inkjet ink comprising a formulation according to claim 1.

9. An inkjet ink comprising a dye according to claim 1, wherein said ink has a λ

_max of 800 nm or more.

10. A method of minimizing visible coloration of a sulfonated water-soluble IR-absorbing naphthalocyanine dye, said naphthalocyanine dye comprising a central metal atom moiety, said method comprising formulating said naphthalocyanine dye at a pH in the range of 4 to 6.5.