Search

JP-7855896-B2 - Inkjet ink composition

JP7855896B2JP 7855896 B2JP7855896 B2JP 7855896B2JP-7855896-B2

Inventors

  • 岡村 久史
  • 小松 英彦
  • 野口 裕未
  • 熊谷 柚花
  • 黄木 康弘

Assignees

  • セイコーエプソン株式会社

Dates

Publication Date
20260511
Application Date
20220330

Claims (4)

  1. It contains a colorant, a water-soluble organic solvent, and water. The aforementioned colorant comprises a compound (A) in which Me is Cr in the structure represented by the following formula (1), and a compound (B) in which Me is Co in the structure represented by the following formula (1). The mass ratio of compound (B) to compound (A) is greater than 0 and less than or equal to 0.06. The colorant further comprises a compound (C) having a structure represented by the following formula (2), The mass ratio of compound (A) and compound (B) to compound (C) is 4 or more and 20 or less. Inkjet ink composition. (In formula (2), Me is Cr or Co, and X1 and X2 are each independently a chlorine atom or an amino group, provided that X1 and X2 are not both chlorine atoms at the same time.)
  2. The inkjet ink composition according to claim 1, wherein the mass ratio of compound (B) to compound (A) is 0.005 or more and 0.06 or less.
  3. The inkjet ink composition according to claim 1 or 2 , wherein the content of the colorant is 5% by mass or less with respect to the total amount of the inkjet ink composition.
  4. An inkjet ink composition according to any one of claims 1 to 3 , further comprising one or more selected from the group consisting of C.I. Reactive Orange 12 and C.I. Reactive Red 24:1.

Description

This invention relates to an inkjet ink composition. Inkjet printing is being explored not only for recording images on recording media but also for textile printing, and various ink compositions for inkjet printing are being investigated. For example, Patent Document 1 describes an inkjet ink composition for textile printing that possesses color development and fastness by specifying the types of rust inhibitors and pH adjusters. Japanese Patent Publication No. 2012-153754 This flowchart shows an example of the recording method according to this embodiment. The following describes in detail embodiments of the present invention (hereinafter referred to as "these embodiments"), but the present invention is not limited thereto, and various modifications are possible without departing from its essence. 1. Inkjet Ink Composition The inkjet ink composition of this embodiment (hereinafter also referred to as "ink composition") comprises a colorant, a water-soluble organic solvent, and water, wherein the colorant comprises compound (A) in which Me is Cr (chromium) in the structure represented by the following formula (1), and compound (B) in which Me is Co (cobalt) in the structure represented by the following formula (1), and the mass ratio of compound (B) to compound (A) (compound (B) / compound (A)) is greater than 0 and less than or equal to 0.06. According to this embodiment, an ink composition can be obtained that has excellent color development and lightfastness, can suppress nozzle clogging even if the print head dries out after long-term storage, and can improve clogging recovery. Although the reason why this embodiment yields such excellent results is not entirely clear, the inventors of the present invention surmise the following: An inkjet ink composition containing a colorant comprising compound (A) and compound (B), such as C.I. Reactive Black 8, has poor color development and lightfastness, and nozzle clogging occurs after long-term storage due to drying of the print head. Compound (A) exhibits excellent color development and high solubility in solvents such as water, resulting in superior clogging recovery. However, due to its superior solubility, it tends to have poor lightfastness. Compound (B), on the other hand, exhibits excellent lightfastness, but has very poor solvent solubility and tends to have poor color development. However, the colorant according to this embodiment contains compound (A) and compound (B), and their mass ratio is within a specific range. Therefore, it is presumed that a synergistic effect between compound (A) and compound (B) can be achieved, resulting in an ink composition with excellent color development, lightfastness, and clogging recovery properties. However, the reasons are not limited to this. Next, we will explain each component contained in the ink composition. 1.1. Pigment The ink composition contains, as a colorant, compound (A) in which Me is Cr in the structure represented by formula (1) above, and compound (B) in which Me is Co in the structure represented by formula (1) above. In the colorant, the mass ratio of compound (B) to compound (A) (compound (B) / compound (A)) is greater than 0 and less than or equal to 0.06. Such a colorant is a reactive dye. The colorant may be used alone or in combination of two or more types. To obtain an ink composition with superior color development, lightfastness, and clogging recovery properties, the mass ratio of compound (B) to compound (A) (compound (B) / compound (A)) is preferably 0.005 or more and 0.06 or less. The colorant further contains compound (C) having a structure represented by the following formula (2), and preferably the mass ratio of compound (A) and compound (B) to compound (C) ((compound (A) + compound (B)) / compound (C)) is 4 or more and 20 or less. Compound (C) may be included alone or in combination of two or more types. In formula (2), Me is either Cr or Co, and X1 and X2 are independently either a chlorine atom or an amino group. However, X1 and X2 are not both chlorine atoms at the same time. When the colorant contains compound (C) along with compound (A) and compound (B) in a specific mass ratio ((compound (A) + compound (B)) / compound (C)), it exhibits superior lightfastness and clogging recovery, and tends to have even better color development on fabrics containing one or more of cotton and silk as raw yarn (hereinafter simply referred to as "cotton and silk fabrics"). In particular, it tends to have even better color development on silk. The reason for this is not clear, but the inventors of the present invention surmise the following. In other words, good color development is obtained when X1 and X2 simultaneously possess chlorine atoms in the structure represented by formula (2). On the other hand, in compound (C), X1 and X2 are not simultaneously chlorine atoms; one X1 and X2 is a chlorine atom and the other is an amino group, or both are amino groups. Therefore, good color development te