NONAQUEOUS INKJET INK COMPOSITION

Abstract

An object is to provide a nonaqueous inkjet ink composition offering excellent solid filling property and anti-mottling property, as well as excellent ink stability, discharge stability, and scratch resistance, even when printed at high speed on printing targets whose printing face is constituted by a polyvinyl chloride, ethylene-vinyl acetate-based copolymer, or other vinyl-based polymer, etc. As a solution, a nonaqueous inkjet ink composition is provided that contains acrylic-based resin, organic coloring pigment and/or carbon black, alumina, pigment dispersant, and organic solvent, wherein the organic solvent comprises propylene carbonate, diethylene glycol dialkyl ether, and dipropylene glycol alkyl ether acetate, and alumina is contained by 5 to 30 parts by mass relative to 100 parts by mass representing the total of organic coloring pigment and carbon black.

Claims

1. A nonaqueous inkjet ink composition containing acrylic-based resin, organic coloring pigment and/or carbon black, alumina, pigment dispersant, and organic solvent, wherein: the organic solvent comprises propylene carbonate, diethylene glycol dialkyl ether, and dipropylene glycol alkyl ether acetate; and alumina is contained by 5 to 30 parts by mass relative to 100 parts by mass representing a total of organic coloring pigment and carbon black.

2. The nonaqueous inkjet ink composition according to claim 1, wherein the diethylene glycol dialkyl ether comprises diethylene glycol ethyl methyl ether and/or diethylene glycol diethyl ether.

Description

EXAMPLES

[0067] The present invention is explained in greater detail below using examples; however, the present invention is not limited to these examples. It should be noted that, unless otherwise specified, “%” means “% by mass,” while “part” means “part by mass.”

[0068] The materials used in the Examples and Comparative Examples below are listed below. All components other than solvents are expressed in solids content.

[0069] In the table, the unit of values in the rows pertaining to pigments, dispersants, resin, solvents and total is “% by mass.”

<Organic Pigments>

[0070] G01 (LEVASCREEN Yellow G01 (P.Y. 150)) (manufactured by Lanxess AG)

[0071] RGT (FASTOGEN Super Magenta RGT) (manufactured by DIC Corporation)

[0072] D7110F (HELIOGEN Blue D7110F) (manufactured by BASF Japan Ltd.)

<Carbon Black>

[0073] MA7 (Carbon Black MA7) (manufactured by Mitsubishi Chemical Corporation)

<Other Pigments>

[0074] BARIFINE 20 (Barium Sulfate) (manufactured by Sakai Chemical Industry Co., Ltd.)

[0075] BARIFINE 40 (Barium Sulfate) (manufactured by Sakai Chemical Industry Co., Ltd.)

<Alumina>

[0076] AEROXIDE Alu C (manufactured by Nippon Aerosil Co., Ltd., average primary particle size 80 nm, specific surface area 100 m.sup.2/g)

<Pigment Dispersants>

[0077] PB822: AJISPER PB822 (manufactured by Ajinomoto Fine-Techno Co., Inc.)

[0078] SOLSPERSE 56000 (manufactured by Lubrizol Corporation)

[0079] SOLSPERSE 39000 (manufactured by Lubrizol Corporation)

<Resin>

[0080] BR-87: DIANAL BR-87 (manufactured by Mitsubishi Chemical Corporation, glass transition temperature 105° C., mass average molecular weight 25,000) (acrylic-based resin)

Examples 1 to 5 and Comparative Examples 1 to 4

<Manufacturing of Nonaqueous Inkjet Ink Compositions>

[0081] According to the recipes in Table 1 (compounding ratio of each material is based on % by mass), the respective materials were mixed under agitation to obtain the nonaqueous inkjet ink compositions in Examples 1 to 5 and Comparative Examples 1 to 4.

<Printing Method>

[0082] The nonaqueous inkjet ink compositions in Examples 1 to 5 and Comparative Examples 1 to 4 were loaded in a commercial inkjet printer and subjected to solid printing on polyvinyl chloride sheets in a high-speed printing mode, to obtain the printed matters in Examples 1 to 5 and Comparative Examples 1 to 4.

[0083] These printed matters were measured/evaluated for the properties below.

[0084] In the evaluations below, ratings A and B indicate levels suitable for practical use, while ratings C and D indicate levels that fall short for practical use.

(Viscosity)

[0085] The 25° C. viscosity of each of the nonaqueous inkjet ink compositions in Examples 1 to 5 and Comparative Examples 1 to 4 was measured using a viscometer (manufactured by Toki Sangyo Co., Ltd., model: RE100L).

(Scratch Resistance)

[0086] Each of the nonaqueous inkjet ink compositions in Examples 1 to 5 and Comparative Examples 1 to 4 was subjected to solid printing on a polyvinyl chloride sheet (product name: MD5, manufactured by MEAMARK (UK) Ltd.) in a high-speed printing mode, and the coating film was rubbed 100 times with a bleached cloth under a load of 500 g using a Gakushin-type abrasion tester (manufactured by Daiei Kagaku Seiki Mfg. Co., Ltd.) to visually observe the degree of removal of the coating film, and the result was evaluated according to the criteria below:

[0087] A: The coating film was not removed.

[0088] B: The coating film was scratched at the surface.

[0089] C: The coating film was somewhat removed.

[0090] D: The coating film was noticeably removed.

(Fine Print Reproducibility)

[0091] The nonaqueous inkjet ink compositions in Examples 1 to 5 and Comparative Examples 1 to 4 were subjected to solid printing on polyvinyl chloride sheets (product name: MD5, manufactured by MEAMARK (UK) Ltd.) in a high-speed printing mode, and the results were visually evaluated for degree of clarity of fine print (smudged characters, garbled characters).

[0092] Evaluation Criteria

[0093] A: Not smudged nor garbled, and clear.

[0094] B: Smudged and garbled, but legible.

[0095] C: Smudged and garbled, and hardly legible.

(Solid Filling Property)

[0096] Each of the nonaqueous inkjet ink compositions in Examples 1 to 5 and Comparative Examples 1 to 4 was subjected to solid printing on a polyvinyl chloride sheet (product name: MPI 1000 Series, manufactured by Avery Dennison Corporation) in a high-speed printing mode, and the result was visually evaluated for filling of solid areas based on whether or not the images have voids, that is, if the solid areas are filled properly.

[0097] Evaluation Criteria

[0098] A: There are no voids.

[0099] B: There are some voids.

[0100] C: There are many voids.

(Anti-Mottling Property)

[0101] Each of the nonaqueous inkjet ink compositions in Examples 1 to 5 and Comparative Examples 1 to 4 was subjected to solid printing in mixed colors (red, blue, green) on a polyvinyl chloride sheet (product name: MPI 1000 Series, manufactured by Avery Dennison Corporation) in a standard mode, and the result was visually evaluated for mottled images (blotchy patterns).

[0102] Evaluation Criteria

[0103] A: Mottling did not occur.

[0104] B: Slight mottling occurred.

[0105] C: A lot of mottling occurred.

(Ink Stability)

[0106] Each of the nonaqueous inkjet ink compositions in Examples 1 to 5 and Comparative Examples 1 to 4 was stored in a glass screw-top bottle. The bottle was kept stationary for 7 days under a temperature condition of 60° C., while being evaluated visually for presence or absence of sediments.

[0107] Evaluation Criteria

[0108] A: No sediments were found.

[0109] B: Sediments were found after 3 days.

[0110] C: Sediments were found after 1 day.

(Discharge Stability)

[0111] Each of the nonaqueous inkjet ink compositions in Examples 1 to 5 and Comparative Examples 1 to 4 was subjected to printing on polyvinyl chloride sheets (product name: MPI 1000 Series, manufactured by Avery Dennison Corporation), and the result was evaluated based on the number of sheets having unprinted areas.

[0112] Evaluation Criteria

[0113] A: Unprinted areas occurred on or after the 71st sheet, or unprinted areas did not occur until the 100th sheet.

[0114] B: Unprinted areas occurred on or between the 51st and 70th sheets.

[0115] C: Unprinted areas occurred on or between the 31st and 50th sheets.

[0116] D: Unprinted areas occurred on or before the 30th sheet.

TABLE-US-00001 TABLE 1 Examples Comparative Examples 1 2 3 4 5 1 2 3 4 Organic G01 3.00 3.00 3.00 3.00 3.00 3.00 pigments RGT 3.00 D7110F 3.00 Carbon MA7 3.50 black Pigment PB822 1.44 1.32 1.44 0.24 0.24 1.20 1.44 1.44 1.68 dispersants SOLSPERSE 56000 1.20 SOLSPERSE 39000 1.40 Alumina AEROXIDE Alu C 0.60 0.30 0.60 0.60 0.60 1.20 Barium BARIFINE 20 0.60 sulfates BARIFINE 40 0.60 Resin BR-87 8.00 8.00 8.00 9.00 9.00 8.00 8.00 8.00 8.00 Organic Diethylene glycol 36.96 37.38 36.96 35.96 35.26 37.80 36.96 36.96 36.12 solvents diethyl ether Diethylene glycol 30.00 30.00 30.00 30.00 30.00 30.00 30.00 30.00 30.00 ethyl methyl ether Propylene carbonate 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 Dipropylene glycol 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 10.00 methyl ether acetate Total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 Viscosity (mPa .Math. s) 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 6.0 Scratch resistance A B A A A C B B A Fine writing property A A A A A A A A A Solid filling property A A A A A A A A A Anti-mottling property A A A A A A A A A Ink stability A A A A A A C C C Discharge stability A A A A A A A A A

[0117] Examples 1 to 4 conforming to the present invention demonstrated excellent scratch resistance, fine writing property, solid filling property, anti-mottling property, ink stability, and discharge stability. In particular, Examples 1 and 3 to 5 received rating A for all of the above because their dispersant contents were appropriate. Example 2 received B only for scratch resistance. By contrast, Comparative Example 1, which did not contain alumina pigment, led to deterioration in scratch resistance. Comparative Examples 2 and 3, in which barium sulfate was compounded in place of alumina pigment, showed deterioration in scratch resistance and ink stability. Comparative Example 4, which contained a higher level of dispersant, exhibited deterioration in ink stability.