JPH0229471A - ink composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an ink composition used in an inkjet recording device. More specifically, the present invention relates to an ink composition in which inkjet recording is performed at a temperature higher than room temperature.

1. Prior Art 1 Inkjet recording is excellent in quietness during recording and high-speed printing performance. BACKGROUND ART Liquid ink compositions based on water or the like have conventionally been used as ink compositions for inkjet recording. However, since ink is recorded by soaking into the paper, it has the disadvantage that when recording on paper where ink easily soaks, bleeding occurs, the periphery of the recorded dots becomes unclear, and the print quality deteriorates.

For this reason, as an ink composition that provides good print quality regardless of paper quality, U.S. Patent No. 4390369.46593
Publication No. 83, JP 55-54368.58-1082
No. 71.61-83268 proposes a method in which a hot-melt ink composition that is solid at room temperature is used, the solid ink is heated and melted at a high temperature, the ink is jetted, and the ink is cooled and solidified on recording paper to form recording dots. has been done.

(Problems to be Solved by the Invention) In water-based ink compositions, the print quality depends on the paper quality, ranging from good print quality to extremely poor print quality depending on the paper quality of the recording paper. In fact, it has not been possible to create an ink composition that satisfies both of these requirements, as it takes a long time to dry the ink after printing.Furthermore, conventional hot-melt ink compositions have problems with compatibility with recording paper, Although the drying properties after printing are good, the adhesion strength to the recording paper is low because the ink droplets are rapidly cooled and solidified on the surface of the recording paper during recording, and the ink image may peel off due to external friction, heat, pressure, etc., and the ink image becomes smudged. We are facing the problem of causing such problems.

The present invention solves the above-mentioned problems,
The objective is to provide an ink composition that has high adhesion strength and provides high print quality regardless of the substrate of the recorded material.

1 Means for Solving Problems 1 The ink composition of the present invention is an ink composition comprising a vehicle and a coloring material that is ejected from an inkjet recording device at a temperature higher than room temperature. (a) 50% to 80% by weight of ketones with a melting point of 60°C to 110°C; (b) 5% to 15% by weight of ketones with a melting point of 60°C to 110°C;
Amides at 10°C and (c) 5 to 30% by weight
It is characterized by being composed of a wax having a melting point of 60° C. to 110° C. in weight percent, and (d) a coloring material in a weight percent range of 3 weight percent to 10 weight percent. Furthermore, as ketones, stearon and lauron, and as amides, carbon number is 1.
It is characterized by being selected from fatty acid amides of 2 to 22, petroleum wax, carnauba wax, montan wax as waxes, and dyes as coloring materials.

The amount of ketones added as a vehicle is preferably 50% by weight (hereinafter abbreviated as wt%) to 80% by weight. If the amount added is 50 wt%, the thermal stability of the ink composition will be poor, resulting in discoloration, changes in physical properties, etc., and if it exceeds 80 wt%, the initial physical properties (viscosity, etc.) of the ink composition will be poor. ) as the ink hardness increases, the ink hardness decreases significantly, resulting in a decrease in the abrasion resistance of the recorded material. Further, in order to realize high responsiveness of the print head (responsiveness of 2 to 3 KHz or more), it is preferable that the ink viscosity is kept low, and the amount added for this purpose is more preferably 50 wt% to 70 wt%.

Further, the amount of amides used as a vehicle to be added is preferably 5 wt% to 15 wt%. If the amount added is 5 wt%, the solubility of the dye as a coloring material in the ink composition will decrease significantly, making it impossible to obtain the desired print density, and if it exceeds 15 wt%, In this case, the initial physical properties (viscosity) of the ink composition increase and the thermal stability of the ink composition deteriorates. In addition, in order to achieve high responsiveness of the print head, it is preferable to keep the ink viscosity low, and for this purpose, the addition amount is 5wt%.
to 10 wt% is more preferable.

Furthermore, waxes as a vehicle are effective in improving the hardness of the ink composition and in turn improving the abrasion resistance of printed matter, and the amount added thereof is preferably from 5 wt% to 30 wt%. If the amount added is 5 wt % without grooves, it will not be effective in improving the abrasion resistance of printed matter, and if it exceeds 30 wt %, the solubility of the dye will decrease.

In addition, the melting points of ketones, amides, and waxes as vehicles should be considered when considering the stability of the ink image under high temperatures of printed matter. A temperature of 60° C. or higher is preferable to prevent the occurrence of problems such as sticking to an opposing object, etc.), and a temperature of 110° C. or lower is preferable from the viewpoint of the heating temperature for an inkjet recording device and the heat resistance of the ink.

[Example code] The present invention will be explained below with reference to Examples.

The ink composition of the present invention can be prepared by a known method, in which a vehicle component and a coloring material are mixed, melted by heating to a temperature higher than the melting point of the vehicle component, preferably 80° C. or higher, and then heated and stirred at that temperature. After that, a homogenized/dissolved composition can be obtained, if necessary, by filtering it through a filter in a high temperature molten state and then cooling it. As for ink physical properties, the viscosity at an ink temperature of approximately 80°C to 120°C during operation is 15.0 milliscal seconds (mPa, s) based on the ink supply stability and ink droplet formation flight stability under high-speed response of the head. The following are required, and in order to achieve even higher responsiveness (to achieve responsiveness of 2 to 3 KH2 or higher), 7. 0 mPa, s to 2. 0 mPa,s is more preferable.

Surface tension affects meniscus formation near the nozzle.5
0 millinewtonmmeter (mN/m) or less is preferable.

As the ketones having a melting point of 60°C to 110°C, waxy dialkyl ketones are preferable, and specifically stearon (Kaohwax T-1: produced by Kao Corporation, mpnia 5) is preferable.
-85°C), Lauron (mp: 60-70°C) are selected. Moreover, these can also be used in combination of two or more types depending on the case.

Further, as the amides having a melting point of 60°C to 110°C, saturated or unsaturated fatty acid amides (carbon number 12-22) are preferable, and specifically, erucic acid amide, lauric acid amide, stearic acid amide, palmitic acid amide Amide, behenic acid amide, brassic acid amide, Amide HT-P, C (manufactured by Lion Corporation), fatty acid amide-3, T, P, (manufactured by Kao Corporation), etc. are selected. Moreover, these can also be used in combination of two or more types depending on the case.

In addition, waxes with a melting point of 60°C to 110°C include:
For example, paraffin or paraffin wax selected from petroleum waxes, carnauba wax, montan wax, etc. are selected. Specifically, (Paraffin) N-paraffin and isoparaffin (paraffin wax) with carbon numbers from 23 to 32 NO1140, 150, 155
．． 16 SB+5PY-0145, 3040, 3035 (microcrystalline wax, others) Hi-Mitsuku 2045.1045 Cartwax-3735, 3640 (all manufactured by Nippon Seiro Co., Ltd.) (Montan wax and its derivatives) Hoechstwax-S , SW, LP, etc. are selected.

Moreover, as the coloring material, oil-soluble dyes having heat resistance and water resistance are preferable.

Specifically, [Black dye] C,1, Solvent Black 3,22,23C,1, Acid Black 123 Sumiblast Flac-G (BKGl, 3BA(S
umiplast Black G (BKG), 3BA
) (manufactured by Sumitomo Chemical Co., Ltd.) Sumisol Black ARsol (Sumisol Black ARsol,) (
(Same as above) [Yellow Dye Co.
5pilon Yellow GRH5special)
(Manufactured by Hodogaya Chemical Industry Co., Ltd.) Sumiplast Yellow GG, FC (Sumiplast Yellow GG, FC)
(manufactured by Sumitomo Chemical Co., Ltd.) [Red, magenta dye] C01, Solvent Red 8, 49, 81, 82° 83
．． 84,100゜109.121 C, 1, Disperse Red 9 Sumifira Strebbee AS, 3B, FB (Sumip
last Red AS, 3B, FB) (manufactured by Sumitomo Chemical Co., Ltd.) Eyesense Iron Red-GEE Special (Ai
zen 5pilon Red GEE 5p
(manufactured by Hodogaya Chemical Industry Co., Ltd.) [Blue, cyan dye] C, 1, Solvent Blue 11. ．． 12, 25, 36,
55. 73 Sumiplast Blue 3R, BG (Sumiplast Blue 3R, BG) (
Manufactured by Sumitomo Chemical Co., Ltd.) Sumiflast Turquoise Blue B (Sumipl)
ast Turquoise Blue B) (same as above) [Complementary color dye]
n 5pilon Violet C-R1 () (manufactured by Hodogaya Chemical Industry Co., Ltd.)
en 5pilon Yellow C-(J[new
) (Same as above) Aizen Methyl Violet Ba5e
) (Same as above) Aizen Crystal Viole
(same as above) Aizen Methyl
Violet pure 5special) (Same as above) Aizen Victoria pure Blu
e BOHcone, ) (same as above)
Aizen SBT Orange '6
S, P, T Orange 6) (same as above), etc.

The amount of the coloring material added is preferably 10.0 weight percent or less, and more preferably 5.0 weight percent or less in consideration of flight stability and appropriate viscosity under high response of the head. In addition, two or more types of dyes can be appropriately mixed and used for adjusting the color tone.

Furthermore, since the ink composition of the present invention is printed at a temperature higher than room temperature, an antioxidant can be added as appropriate to prevent oxidation of the composition due to heat or the like. Specifically, dibutylhydroxytoluene (BIT),
Irganox 1010゜1035, 1035FF
, 1076 (manufactured by Japan Chiheki Iki Co., Ltd.)
etc.

Next, specific examples of the above components will be shown.

Example 1 Composition Weight Percent Colorant: C, 1, Vine Rubber 23
3. 0 Vehicle: Stearon
67.2: Fatty acid 1 Mybee 3 9
．． 7: Carnauba wax 20.0 Antioxidant: Cyphytylhydroxytoluene
0.1 The above acid mixture was melted at 120°C, mixed under heating for 3 hours, filtered under pressure using a Teflon membrane filter with a pore size of 5 microns in the high temperature molten state, and then heated to 100°C. The viscosity is 5.0
An ink composition having a surface tension of 29.0 mN/m in mPa,s was obtained.

Next, the recording head of a known ink-on-demand type impulse inkjet recording device compatible with heat-melting ink was heated, the ink composition shown in Example 1 was filled into it, and the ink composition was kept at 100°C. , bond paper,
After bit image printing, character printing, etc. were performed on PPC paper, etc., A1 to A4 were evaluated, and the following results were obtained.

(A1) Printing abrasion resistance: After printing on various types of recording paper, the presence or absence of staining caused by rubbing the printed surface with tissue paper was evaluated based on the elapsed time after printing. - No staining after 10 seconds 01. Suitable (■) - No occurrence after 20 to 30 seconds 94. Appropriate (0) - Occurred after 30 seconds or more 11. When classified and evaluated by unsuitability (X), all of them were rated "suitable" or higher, although there were some differences depending on the paper quality.

(A2) Printed matter blocking property = Blank recording paper is stacked on top of the recording paper at a high temperature of 60°C, and after being left under pressure from above for 24 hours, ink smudges on the recording paper surface and the stacked recording paper The presence or absence of ink transfer was examined, but the dot diameter remained the same as before, no ink bleeding occurred, and no ink transfer was observed.

・No blocking (0) ・Blocking (×) (A3) Environmental abrasion resistance of ink image: A recorded material on which an ink image is formed can be touched by sweeping with a finger or the like under normal circumstances. , sweeping with cloth, etc., and sweeping with paper, etc. were evaluated: - No missing or smudged ink image - Good (O) - Partially missing or smudged ink image - Suitable (0) - Significant missing or smudged ink images - Unsuitable (x) (A4) Ink heat resistance: The discoloration of the vehicle composition after one month of leaving the ink composition and the vehicle composition excluding the dye component at 120°C. The degree of discoloration, discoloration, and physical properties (viscosity, thermal properties, etc.) of the ink composition were evaluated.・The degree of discoloration is extremely small, and there is almost no change in physical properties.
...Favorable (O): Some discoloration is observed in the vehicle composition, but almost no discoloration or change in physical properties is observed in the ink composition....Suitable (0): Discoloration is clearly observed, and no change in physical properties is observed. Is recognized
...When classified and evaluated by unsuitability (×),
All scores were ``suitable'' or better. From the three evaluation results, printed matter with good dot reproducibility and scratch resistance was obtained.

Example 2 Ink compositions shown in Table 1 from 2-1 to 2-8 were obtained in the same manner as in Example 1.

Comparative Example Ink compositions shown in Table 1 C-1 to C-5 were obtained in the same manner as in Example 1.

For Example 2 and Comparative Example, A1-A as in Example 1.
4 was evaluated, and the results shown in Table 2 were obtained. Further, the evaluation status of each comparative example was as shown below.

Discoloration was observed because the amount of C-1-ketones added was small and the amount of amides added was large. Moreover, when a dye other than black was used, the problem was significant.

Since the amount of C-2 diketones added was large and the amount of waxes added was small, the evaluation A3 (environmental abrasion resistance) was extremely poor.

C-4, 5: Because waxes and amides used components with lower melting points than the specified ones, a produkking phenomenon was observed when the ink image was left at high temperatures.

Note that the present invention is not limited to the above embodiments.

1 Effects of the Invention 1 As described above, in an ink composition consisting of a vehicle and a coloring material that is ejected from an inkjet recording device at a temperature higher than room temperature, as the vehicle and coloring material, (a, ,) 50% to 80% by weight of ketones with a melting point of 60°C to 110°C, and (b) 51
t percent to 15 weight percent of amides with a melting point of 60° C. to 110° C.; and (c) 51 ffl percent to 30 weight percent of amides with a melting point of 60° C. to 11-0° C.
and (d) a coloring material of 3 to 10 weight percent, further comprising stearon, lauron as ketones, carbon number 12 to 1 as amides.
8 fatty acid amide, petroleum wax, carnauba wax, montan wax as waxes, and dyes as coloring materials, it has high fixing strength, scratch resistance, and dot reproduction regardless of the quality of the recording paper. This has the effect that good printing with good quality can be obtained. In addition, by using a waxy dialkyl ketone as the main component of the vehicle structure, it protects the ink composition from heat compared to other vehicles that have relatively weak heat resistance properties when used alone. It has the special effect of increasing the

Claims (5)

[Claims] (1) In an ink composition consisting of a vehicle and a coloring material that is ejected from an inkjet recording device at a temperature higher than room temperature, the vehicle and coloring material (a) have a melting point of 50% to 80% by weight of 60°C or higher; (b) 5% to 15% by weight of amides with a melting point of 60°C to 110°C; (c) 5% to 30% by weight of a wax with a melting point of 60°C to 110°C. (d) 3 to 10 weight percent of a coloring material. (2) The ink composition according to claim 1, wherein the ketone is selected from stearon and lauron. (3) The ink composition according to claim 1, wherein the amide is selected from fatty acid amides having 12 to 22 carbon atoms. (4) Waxes include petroleum wax, carnauba wax,
The ink composition according to claim 1, wherein the ink composition is selected from montan waxes. (5) The ink composition according to claim 1, wherein the coloring material is selected from dyes.