WATER-BASED INK, PRINTED RECORDING MEDIUM, AND INK CARTRIDGE

Abstract

A water-based ink for inkjet recording, includes: a pigment; water; and an acidic preservative. The pigment is preferably a self-dispersing pigment. The acidic preservative preferably includes at least one selected from the group consisting of a polyvalent unsaturated fatty acid, a polyvalent unsaturated fatty acid salt, dehydroacetic acid, and a dehydroacetate. A content of the acidic preservative in the water-based ink is preferably 0.5% by mass to 5.0% by mass relative to a total mass of the water-based ink. The water-based ink preferably further includes a surfactant. The water-based ink preferably further includes a penetrant which includes at least one selected from the group consisting of 1,2-hexanediol, 3-methyl-1,5-pentanediol, and triethylene glycol-n-butyl ether (BTG).

Claims

1. A water-based ink comprising: a pigment; water; and an acidic preservative.

2. The water-based ink according to claim 1, wherein the pigment is a self-dispersing pigment.

3. The water-based ink according to claim 1, wherein the acidic preservative comprises at least one selected from the group consisting of a polyvalent unsaturated fatty acid, a polyvalent unsaturated fatty acid salt, dehydroacetic acid, and a dehydroacetate.

4. The water-based ink according to claim 3, wherein the polyvalent unsaturated fatty acid is sorbic acid, and the polyvalent unsaturated fatty acid salt is a sorbate.

5. The water-based ink according to claim 4, wherein the sorbate comprises at least one selected from the group consisting of potassium sorbate and sodium sorbate.

6. The water-based ink according to claim 3, wherein the dehydroacetate is sodium dehydroacetate.

7. The water-based ink according to claim 1, wherein a content of the acidic preservative in the water-based ink is 0.5% by mass to 5.0% by mass relative to a total mass of the water-based ink.

8. The water-based ink according to claim 1, further comprising a surfactant.

9. The water-based ink according to claim 8, wherein the surfactant is an acetylene-based surfactant.

10. The water-based ink according to claim 1, further comprising a penetrant which comprises at least one selected from the group consisting of an alkylene diol and a glycol ether compound.

11. The water-based ink according to claim 1, further comprising a penetrant which comprises at least one selected from the group consisting of 1,2-hexanediol, 3-methyl-1,5-pentanediol, and triethylene glycol-n-butyl ether (BTG).

12. The water-based ink according to claim 8, wherein an amount of the acidic preservative and an amount of the surfactant satisfy Condition (X):
0.5≤A/B≤50, wherein A is the amount of the acidic preservative (% by weight), and B is the amount of the surfactant (% by weight).

13. The water-based ink according to claim 10, wherein an amount of the acidic preservative and an amount of the penetrant satisfy Condition (Y):
0.1≤A/C≤5, wherein A is the amount of the acidic preservative (% by weight), and C is the amount of the penetrant (% by weight).

14. The water-based ink according to claim 1, further comprising a penetrant which comprises at least one selected from the group consisting of 1,2-hexanediol, 3-methyl-1,5-pentanediol, and triethylene glycol-n-butyl ether (BTG), wherein the acidic preservative comprises at least one selected from the group consisting of a polyvalent unsaturated fatty acid, a polyvalent unsaturated fatty acid salt, dehydroacetic acid, and a dehydroacetate.

15. The water-based ink according to claim 14, wherein the polyvalent unsaturated fatty acid is sorbic acid, and the polyvalent unsaturated fatty acid salt is a sorbate.

16. The water-based ink according to claim 1, wherein the water-based ink is suitable for inkjet recording.

17. A printed recording medium comprising: a recording medium; and the water-based ink according to claim 1, printed on the recording medium.

18. An ink cartridge comprising the water-based ink according to claim 1 stored therein.

Description

EXAMPLES

[0051] Next, examples of the present disclosure will be described together with comparative examples. Note, the present disclosure is not limited or restricted by the following examples and comparative examples.

Examples 1 to 28 and Comparative Examples 1 to 4

[0052] Components other than pigments in the water-based ink compositions (Tables 1 to 3) were uniformly mixed to obtain ink solvents. Next, the ink solvent was added to the pigment dispersed in water, and this was uniformly mixed. Then, the obtained mixture was filtered using a cellulose acetate membrane filter (pore diameter of 3.00 μm) made by Toyo Roshi Kaisha, Ltd. to obtain the water-based ink for inkjet recording in Examples 1 to 28 and Comparative Examples 1 to 4. Note, as shown in Table 1, Examples 1 to 15 used either potassium sorbate or sodium sorbate as the acidic preservative. Furthermore, as shown in Table 2, Examples 16 to 28 used sodium dehydroacetate as the acidic preservative.

[0053] The water-based inks of examples 1 to 28 and comparative examples 1 to 4 were subjected to (a) recording density evaluation and (b) preservation evaluation according to the following methods.

[0054] (a) Recording Density Evaluation

[0055] The water-based inks of Examples 1 to 28 and Comparative Examples 1 to 4 were applied to a recording medium (“Multipaper Super White+” made by Askul Corporation) such that the application amount per unit area was approximately 0.90 mg/cm2, producing an evaluation sample. Optical densities (OD value) of five locations in the evaluation sample were measured using a SpectroEye spectrophotometer (light source: D50, viewing angle: 2°, ANSI-T) made by X-Rite, Incorporated, and the average value was obtained. Next, the optical density (OD value) difference (40D) was calculated by subtracting the optical density (OD value) in Comparative Example 1, in which the evaluation sample was produced using only a water-based black pigment ink (CAB-O-JET® 300) without using an acidic preservative, from the optical density (OD value) in Examples 1 to 14, 16 to 27, Comparative Example 2, and Comparative Example 3. Similarly, the optical density (OD value) difference (40D) was calculated by subtracting the optical density (OD value) in Comparative Example 4, in which the evaluation sample was produced using only a water-based magenta pigment ink (CAB-O-JET® CAB-O-JET 465) without using an acidic preservative, from the optical density (OD value) in Example 15 and Example 28. The recording density was evaluated according to the following evaluation criteria.

[0056] Recording Density Evaluation: Evaluation Criteria

[0057] AA: Improvement of optical density (OD value) (40D) was 0.1 or more.

[0058] A: Improvement of optical density (OD value) (40D) was 0.06 to 0.09.

[0059] B: Improvement of optical density (OD value) (40D) was 0.03 to 0.05.

[0060] C: Improvement of optical density (OD value) (40D) was 0.02 or less.

[0061] (b) Preservative Property Evaluation

[0062] The water-based inks of Examples 1 to 28 and Comparative Examples 1 to 4 were applied to a standard agar culture medium and stored for three days in a 35° C. temperature environment.

[0063] Then, it was visually checked whether a fungal colony had developed in the standard agar culture medium, and the preservative properties were evaluated according to the following evaluation criteria.

[0064] Preservative Property Evaluation: Evaluation Criteria

[0065] A: No colonies developed

[0066] C: A colony developed

[0067] Table 1 to Table 3 show the water-based ink composition and evaluation results of the water-based inks of Examples 1 to 28 and Comparative Examples 1 to 4.

TABLE-US-00001 TABLE 1 Example 1 2 3 4 5 6 7 8 Water-based Pigment CAB-O-JET ® 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 ink 200 (*1) composition CAB-O-JET ® — — — — — — — — (% by weight) 465 (*2) Preservative Potassium sorbate (*3) 3.0 5.0 1.0 0.5 — 5.0 3.0 0.5 Sodium sorbate (*4) — — — — 3.0 — — — Sodium — — — — — — — — dehydroacetate (*5) Proxel GXL(s) (*6) — — — — — — — — Sodium — — — — — — — — L-ascorbate (*7) Wetting Glycerin 13.0  13.0  13.0  13.0  13.0  13.0  13.0  13.0  agent Propylene glycol — — — — — — — — Penetrant Triethylene glycol 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 n-butyl ether 1,2-Hexanediol — — — — — — — — 3-Methyl-1,5- — — — — — — — — pentanediol Surfactant Olfine ® E1010 (*8) 0.2 0.2 0.2 0.2 0.2 0.1 0.1 0.1 Olfine ® E1004 (*9) — — — — — — — — Water Remainder Remainder Remainder Remainder Remainder Remainder Remainder Remainder Ratio Acidic preservative/surfactant 15.0  25.0  5.0 2.5 15.0  50.0  30.0  0.5 Acidic preservative/penetrant 3.0 5.0 1.0 0.5 3.0 5.0 3.0 0.5 Evaluation Optical density AA AA A A B AA AA A (OD value)  (1.57)  (1.56)  (1.52)  (1.50)  (1.48)  (1.56)  (1.55)  (1.50) Preservative A A A A A A A A performance Example 9 10 11 12 13 14 15 Water-based Pigment CAB-O-JET ® 6.0 6.0 6.0 6.0 6.0 6.0 — ink 200 (*1) composition CAB-O-JET ® — — — — — — 3.5 (% by weight) 465 (*2) Preservative Potassium sorbate (*3) 3.0 3.0 0.5 3.0 3.0 3.0 3.0 Sodium sorbate (*4) — — — — — — — Sodium — — — — — — — dehydroacetate (*5) Proxel GXL(s) (*6) — — — — — — — Sodium — — — — — — — L-ascorbate (*7) Wetting Glycerin 13.0  13.0  13.0  13.0  13.0  13.0  16.0  agent Propylene glycol — — — — — — 5.0 Penetrant Triethylene glycol 1.0 — — — 1.0 — 1.0 n-butyl ether 1,2-Hexanediol — 0.5 0.5 — — — 3-Methyl-1,5- — 3.0 4.5 — — — pentanediol Surfactant Olfine ® E1010 (*8) — 0.2 0.2 0.2 — — 0.2 Olfine ® E1004 (*9) 0.2 — — — — — Water Remainder Remainder Remainder Remainder Remainder Remainder Remainder Ratio Acidic preservative/surfactant 15.0  15.0  2.5 15.0  — — 15.0  Acidic preservative/penetrant 3.0 0.9 0.1 — 3.0 — 3.0 Evaluation Optical density AA AA A AA AA AA B (OD value)  (1.54)  (1.55)  (1.50)  (1.55)  (1.54)  (1.54)  (1.00) Preservative A A A A A A A performance (*1): Made by Cabot Specialty Chemicals, Inc. (*2): Made by Cabot Specialty Chemicals, Inc. (*3): Made by Kanto Chemical Co., Ltd. (*4): Made by Kanto Chemical Co., Ltd. (*5): Made by Kanto Chemical Co., Ltd. (*6): Made by Arch Chemicals, Inc.; 450 ppm (*7): Made by Kanto Chemical Co., Ltd. (*8): Acetylene glycol-based surfactant (ethylene oxide (10 mol) adduct of diol): Nissin Chemical Industry Co., Ltd.; active ingredient = 100% (*9): Acetylene glycol-based surfactant (ethylene oxide (4 mol) adduct of diol): Nissin Chemical Industry Co., Ltd.; active ingredient = 100%

TABLE-US-00002 TABLE 2 Example 16 17 18 19 20 21 22 Water-based Pigment CAB-O-JET ® 200 (*1) 6.0 6.0 6.0 6.0 6.0 6.0 6.0 ink CAB-O-JET ® 465 (*2) — — — — — — — composition Preservative Potassium sorbate (*3) — — — — — — — (% by weight) Sodium sorbate (*4) — — — — — — — Sodium dehydroacetate (*5) 0.5 1.0 3.0 5.0 0.5 0.5 0.5 Proxe GXL(s) (*6) — — — — — — — Sodium L-ascorbate (*7) — — — — — — — Wetting Glycerin 13.0  13.0  13.0  13.0  13.0  13.0  13.0  agent Propylene glycol — — — — — — — Penetrant Triethylene glycol 1.0 1.0 1.0 1.0 1.0 1.0 1.0 n-butyl ether 1,2-Hexanediol — — — — — — — 3-Methyl-1,5-pentanediol — — — — — — — Surfactant Olfine ® E1010 (*8) 0.2 0.2 0.2 0.2 0.1 1.0 — Olfine ® E1004 (*9) — — — — — — 0.2 Water Remainder Remainder Remainder Remainder Remainder Remainder Remainder Ratio Acidic preservative/surfactant 2.5 5.0 15.0  25.0  5.0 0.5 2.5 Acidic preservative/penetrant 0.5 1.0 3.0 5.0 0.5 0.5 0.5 Evaluation Optical density A A A AA B A B (OD value)  (1.50)  (1.51)  (1.52)  (1.55)  (1.48)  (1.51)  (1.46) Preservative A A A A A A A performance Example 23 24 25 26 27 28 Water-based Pigment CAB-O-JET ® 200 (*1) 6.0 6.0 6.0 6.0 6.0 — ink CAB-O-JET ® 465 (*2) — — — — — 3.5 composition Preservative Potassium sorbate (*3) — — — — — — (% by weight) Sodium sorbate (*4) — — — — — — Sodium dehydroacetate (*5) 0.5 0.5 0.5 0.5 0.5 0.5 Proxe GXL(s) (*6) — — — — — — Sodium L-ascorbate (*7) — — — — — — Wetting Glycerin 13.0  13.0  13.0  13.0  13.0  16.0  agent Propylene glycol — — — — — 5.0 Penetrant Triethylene glycol — — — 1.0 — 1.0 n-butyl ether 1,2-Hexanediol 5.0 0.1 — — — — 3-Methyl-1,5-pentanediol — 4.9 — — — — Surfactant Olfine ® E1010 (*8) 0.2 0.2 0.2 — — 0.2 Olfine ® E1004 (*9) — — — — — — Water Remainder Remainder Remainder Remainder Remainder Remainder Ratio Acidic preservative/surfactant 2.5 2.5 2.5 2.5 — 2.5 Acidic preservative/penetrant 0.1 0.1 0.1 — — 0.5 Evaluation Optical density A A A B B B (OD value)  (1.51)  (1.51)  (1.50)  (1.46)  (1.46)  (0.98) Preservative A A A A A A performance (*1): Made by Cabot Specialty Chemicals, Inc. (*2): Made by Cabot Specialty Chemicals, Inc. (*3): Made by Kanto Chemical Co., Ltd. (*4): Made by Kanto Chemical Co., Ltd. (*5): Made by Kanto Chemical Co., Ltd.) (*6): Made by Arch Chemicals, Inc.; 450 ppm (*7): Made by Kanto Chemical Co., Ltd. (*8): Acetylene glycol-based surfactant (ethylene oxide (10 mol) adduct of diol): Nissin Chemical Industry Co., Ltd.; active ingredient = 100% (*9): Acetylene glycol-based surfactant (ethylene oxide (4 mol) adduct of diol): Nissin Chemical Industry Co., Ltd.; active ingredient = 100%

TABLE-US-00003 TABLE 3 Comparative Example 1 2 3 4 Water-based ink Pigment CAB-O-JET ® 200 (*1) 6.0 6.0 6.0 — composition CAB-O-JET ® 465 (*2) — — — 3.5 (% by weight) Preservative Potassium sorbate (*3) — — — — Sodium sorbate (*4) — — — — Sodium dehydroacetate (*5) — — — — Proxel GXL(s) (*6) — 0.2 — — Sodium L-ascorbate (*7) — — 0.5 — Wetting Glycerin 13.0 13.0 13.0 16.0 agent Propylene glycol — — — 5.0 Penetrant Triethylene glycol n-butyl 1.0 1.0 1.0 1.0 ether 1,2-Hexanediol — — — — 3-Methyl-1,5-pentanediol — — — — Surfactant Olfine ® E1010 (*8) 0.2 0.2 0.2 0.2 Olfine ® E1004 (*9) — — — — Water Remainder Remainder Remainder Remainder Ratio Acidic preservative/surfactant — — — — Acidic preservative/penetrant — — — — Evaluation Optical densify (OD value) — C B — (1.43) (1.43) (1.47) (0.95) Preservative performance C A C C *1: Made by Cabot Specialty Chemicals, Inc. *2: Made by Cabot Specialty Chemicals, Inc. *3: Made by Kanto Chemical Co., Ltd. *4: Made by Kanto Chemical Co., Ltd. *5: Made by Kanto Chemical Co., Ltd. *6: Made by Arch Chemicals, Inc.; 450 ppm *7: Made by Kanto Chemical Co., Ltd. *8: Acetylene glycol-based surfactant (ethylene oxide (10 mol) adduct of diol): Nissin Chemical Industry Co., Ltd.; active ingredient = 100% *9: Acetylene glycol-based surfactant (ethylene oxide (4 mol) adduct of diol): Nissin Chemical Industry Co., Ltd.; active ingredient = 100%

[0068] As shown in Table 1 and Table 2, improvement in recording density (OD value) was observed in Examples 1 to 28, and the results of the preservative property evaluation were all satisfactory. In particular, the degree of improvement in recording density (OD value) was large in Examples 1, 2, 6, 7, 9, 10, 12 to 14, and 19.

[0069] Conversely, as shown in Table 3, the results of the preservative property evaluation were poor for Comparative Examples 1 and 4, which did not use preservatives. Furthermore, in Comparative Example 2, which used 1,2-dibenzinthiazolin-3-one (product name: PROXEL GXL from Arch Chemicals, Inc.) instead of the acidic preservative, the recording concentration (OD value) was the same as Comparative Example 1. Furthermore, the results of the preservative property evaluation were poor in Comparative Example 3, which used sodium ascorbate in place of the acidic preservative.

[0070] As described above, the water-based ink of the present disclosure can improve the optical density (OD value) of a recorded matter made using a water-based ink without increasing the coloring agent density and can impart preservative properties. The applications of the water-based ink of the present disclosure are not particularly limited, and it can be widely applied to various types of inkjet recording.

[0071] Obviously, numerous modifications and variations of the present invention(s) are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention(s) may be practiced otherwise than as specifically described herein.