JP2000053896A - Oil-soluble ink for ink jet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an oil-soluble ink for ink jet which is excellent in delivery stability and long-term storage stability and gives prints excellent in resistances to scratch and water by compounding a colorant with a specific resin and a highly insulating low-permittivity carrier liquid. SOLUTION: A resin soln. obtd. by heating a monomer which makes the below described highly insulating low-permittivity carrier liquid soluble, a polar monomer, and a polymn. initiator is three-dimensionally crosslinked with a monomer having anchor groups. Then, a polymn. initiator and an insoluble monomer which forms cores are added to the resin soln. and copolymerized to give a highly insulating low-permittivity carrier liquid which contains a resin comprising 60-95 wt.% solvation part having an affinity to the carrier liquid and 40-5 wt.% nonsolvation part having no affinity. This carrier liquid is compounded with a colorant in an amt. of 1-30 wt.% and in an amt. of the sum of the resin and the pigment of 20 wt.% or lower, giving an oil-soluble ink for ink jet which contains particles with a vol. average size of 5 μm or lower and does not contain coarse particles with particle sizes of 10 μm or higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oil-soluble ink for ink-jet printing, and more particularly, to a method for converting a resin contained in an oil-soluble ink into a non-solvate having no affinity with a solvation part having an affinity for a carrier liquid. The present invention relates to an oil-soluble ink for ink jet which has improved jetting stability and long-term storage stability by being composed of a plurality of parts.

[0002]

2. Description of the Related Art Conventionally, as a printer device as an information equipment terminal such as a personal computer, a wire drive that magnetically drives a wire and presses against a platen via an ink ribbon and recording paper as a recording medium to perform printing. Printers using a recording head of an ink jet type, a printer using an ink jet type recording head that discharges ink from nozzles by the action of a piezoelectric element, etc. are used. Attention has been focused on simple non-contact, non-impact ink jet printers suitable for use in offices.

[0003] Ink jet printers are broadly classified into a continuous ejection type and a drop on demand (DOD) type.
2. Description of the Related Art An ink jet printer, which has been most widely used in the past, uses a drop-on-demand system in which small droplets are ejected from nozzles of a printer head only when necessary during a printing operation.

In a conventional DOD printer, ink is supplied from an ink tank to a nozzle and an actuator system in a printer head via a supply system, and the ink is heated by a deforming force of a piezo element or the like or an ink heating means. Ink is ejected from a minute nozzle onto a recording medium using ejection means such as pressure fluctuation due to bubble generation force by a certain heater or the like, dots are formed by the ejected ink, and various images are recorded by a dot pattern. I have.

[0005] The ink used in this DOD printer is:
In general, a water-soluble ink is used, and in many cases, a wetting agent is adjusted with a non-aqueous solvent such as polyhydric alcohols such as ethylene glycol and diethylene glycol to prevent nozzle clogging.

[0006] In such a water-soluble ink containing ethylene glycol, the viscosity increases due to the evaporation of water over time.
There is a problem that ejection becomes unstable at the nozzle tip, drying on general-purpose recording paper is slow, or ink bleeds on the recording paper, so that high-quality printing cannot be obtained.
Special paper such as special coated paper had to be used as the ink jet recording paper.

In order to print on general-purpose recording paper in ink-jet recording, ink that dries instantaneously on the recording paper is required. However, such quick-drying ink dries in the nozzles to prevent clogging. Therefore, oil-based inks containing oleic acid (if necessary, see JP-A-57-170966) and quick-drying inks in which the ink quickly penetrates the recording paper (if necessary, the 58-109570).

In the electrostatic acceleration type ink jet system of the DOD system, a carrier liquid, that is, resin particles are mainly discharged from the ink without containing a large amount of the carrier liquid, and a good recorded image is obtained. Ink resistivity of 1
It is necessary to be at least 0 ⁸ Ω · cm, if the oil-soluble ink (required with highly insulating low-permittivity solvent isoparaffinic having ¹⁰ 10 Ω · cm or more resistivity as a carrier liquid, JP-A 9-193389) has also been proposed.

As another ink, a hot-melt ink using wax or a thermoplastic material has also been proposed. Ink which is solid at room temperature is heated during use to be liquefied and discharged from a nozzle. The ejected ink solidifies when it comes into contact with a medium such as recording paper.

[0010]

However, the above oil-based inks and quick-drying inks have a problem that the frequency of the ink jet recording head is not increased due to the high viscosity, and the printing speed is not improved. There is a problem that high quality printing cannot be realized due to large bleeding.

In the case of the hot melt ink, there is no such a problem, and there is no problem such as clogging of the head because there is no influence of volatilization of the solvent. However, it can be applied only at a low dye concentration. In addition, large liquid droplets are required to obtain a sufficient color density, and the resolution of a printed image is reduced. Further, since a thermoplastic material is used, there are problems such as poor abrasion and bending characteristics.

Accordingly, the present invention provides a method for producing a printed matter,
It is an object of the present invention to provide an oil-soluble ink for inkjet which is excellent in water resistance and excellent in ejection stability and long-term storage stability.

[0013]

Here, means for solving the problems in the present invention will be described. See FIG. 1. (1) The present invention relates to an oil-soluble ink for ink-jet ink containing a colorant, a resin, and a high-insulating, low-dielectric carrier liquid as main components. It is characterized by comprising a solvated part having an affinity and a non-solvated part having no affinity.

As described above, by using the carrier liquid having a high insulating property and a low dielectric constant, it is possible to satisfy the condition of 20 cps or less, which is a suitable viscosity for an ink-jet ink. The non-solvated part, which has no affinity for the liquid, improves the abrasion resistance, and the solvated part, which has an affinity for the high-insulating, low-dielectric-constant carrier liquid that forms the shell, ensures the dispersion stability of the resin particles. Can be improved. In addition, such an amphiphilic resin having both a solvated part and a non-solvated part with respect to a carrier liquid having a high insulating property and a low dielectric constant is called an organosol and is a resin having excellent dispersion stability.

(2) The present invention relates to the above-mentioned (1), wherein the acrylic acid having 10 to 30 carbon atoms in the monomer portion of the resin having an affinity for the high insulating low dielectric constant carrier liquid in the resin. It contains at least one of an ester derivative or a methacrylic acid ester derivative, or has 4 to 10 carbon atoms in a monomer portion of a resin having no affinity for a high insulating low dielectric constant carrier liquid in the resin. Acrylic ester derivatives,
Methacrylic acid ester derivatives, styrene, derivatives of substituted styrene, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyvinyl butyral, rosin, tempel resin, phenol resin,
It is characterized by satisfying at least one of conditions including at least one of an aliphatic hydrocarbon resin, an alicyclic hydrocarbon resin and an aromatic class resin.

As described above, the monomer portion of the resin having an affinity for the carrier liquid having a high insulating property and a low dielectric constant in the resin may be an acrylate derivative or a methacrylic ester derivative having a long straight-chain ester having 10 to 30 carbon atoms. It is preferable to use at least one of the acid ester derivatives. Further, as the monomer portion of the resin having no affinity for the high insulating low dielectric constant carrier liquid in the resin, a short acrylate derivative of a straight ester chain having 4 to 10 carbon atoms, a methacrylate derivative, Styrene, derivatives of styrene, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyvinyl butyral, rosin, tempel resin, phenolic resin, aliphatic hydrocarbon resin, alicyclic hydrocarbon resin, or aromatic It is preferred to use at least one of the group-based resins.

(3) In the present invention, in the above (1) or (2), the weight ratio of the monomer portion of the resin having affinity to the monomer portion of the resin having no affinity in the resin is 6%.
0:40 to 95: 5.

As described above, the weight ratio of the monomer portion of the resin having affinity to the monomer portion of the resin having no affinity is preferably in the range of 60:40 to 95: 5. When the weight of the monomer portion of the resin having the following is less than 60%, sedimentation of the resin particles becomes remarkable, and further, the non-solvated portions are settled, which is not preferable from the viewpoint of re-dispersion of ink. In addition, the weight of the monomer part of the resin having no affinity is 5%.
% Or less, the resin can only be agglomerated and the dispersion stability cannot be obtained.

(4) The invention according to any one of the above (1) to (3), wherein the average volume particle diameter of the particles contained in the oil-soluble ink for ink jet is 5 μm or less, and the coarse particle diameter is 10 μm or more. It is characterized by not containing particles.

Generally, the size of a hole of a filter used for supplying ink from an ink tank to a head portion is 20 to 30 μm. Therefore, in order to prevent clogging in the filter, it is necessary to use an oil-soluble ink jet ink. The average volume particle diameter of the particles contained in the ink is 5 μm or less, and 1
It is necessary not to include coarse particles of 0 μm or more.

(5) In the present invention, in any one of the above (1) to (4), the total ratio of the resin and the colorant to the oil-soluble ink for inkjet is 20% by weight or less, or It is characterized in that the ratio of the colorant to the total of the resin and the colorant satisfies at least one of the conditions of 1 to 30% by weight.

As described above, by setting the total ratio of the resin and the colorant to the oil-soluble ink for ink jet, that is, the ratio of the solid component to 20% by weight or less, a suitable viscosity can be obtained, and the solid component can be further increased. Even if the number is increased, the energy required for ejection is increased, but the ejection stability is lacking. Further, by setting the ratio of the colorant to the total of the resin and the colorant to be 1 to 30% by weight, a suitable color density and saturation can be obtained, and the color density can be increased even if the density of the colorant is further increased. An obstacle such as saturation and, on the contrary, a decrease in saturation occurs.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Here, the procedure of the embodiment of the present invention will be described. First, a stirrer, a thermometer, a reflux condenser, a non-aqueous high-insulating low-dielectric carrier liquid for dispersing resin particles in a flask equipped with a dropping funnel, a monomer that imparts solubility, a monomer having a polar group, and The polymerization initiator is dropped and heated for copolymerization.

As the carrier liquid having a high insulating property and a low dielectric constant in this case, an isoparaffinic organic solvent having an electric resistivity of about 10 ¹⁴ Ω · cm is suitable.
L, H and Solvents 100 (all are trade names manufactured by Exxon) can be used, and these may be used alone or in combination of two or more depending on the specifications. Such an isoparaffinic organic solvent has a solution viscosity at room temperature of 20 cps or less, and therefore sufficiently satisfies the condition of 30 cps or less, which is a suitable viscosity used for inkjet.

In addition, the monomer that gives solubility is n
Hexyl acrylate, n-hexyl methacrylate, 2 ethyl hexyl acrylate, 2 ethyl hexyl methacrylate, lauryl acrylate, lauryl methacrylate, stearyl acrylate, stearyl methacrylate, etc., a linear long methacrylate (methacrylic acid ester) derivative having 10 to 30 carbon atoms, Acrylate (acrylate) derivatives are suitable.

Since a monomer having a polar group has a high affinity for a colorant, it has a function of contributing to the adsorption of the colorant mainly by hydrogen bonding with the colorant or van der Waals force. Another effect is that an ester bond is formed with an anchor group of a monomer having an anchor group to be described later, thereby contributing to a molecular bond between a core, which is a resin insoluble in a solvent, and a shell, which is a soluble resin. As such a monomer having a polar group, acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and the like are preferable.

Next, the resin is cross-linked three-dimensionally,
It is preferable to form a covalent bond between the core portion and the shell portion of the resin particles, add a monomer having an anchor group for stabilizing the dispersion of the colorant, and perform an esterification reaction with the monomer having a polar group. The anchor group reacts with the functional group of the ethylenically unsaturated compound to form a graft copolymer stabilizer, and the ethylenically unsaturated portion of the anchor group undergoes a copolymerization reaction with the comonomer in the non-aqueous medium. And a stable dispersion can be obtained. Thus, the shell is a graft copolymer that is conditioned by a polymerization reaction of at least two comonomers.

The monomer having such an anchor group is an insoluble component, and its content may be small. For example, glycidyl acrylate and glycidyl methacrylate are preferred. At the time of the esterification reaction, a small amount of a base such as ethylamine, vinylpyridine, imidazole or the like is added as a catalyst.

Next, an insoluble monomer serving as a core and a polymerization initiator are added, and the mixture is heated and copolymerized to prepare a resin dispersion. In this process, a copolymerization reaction with a polymer for a shell is carried out. The polymer is adjusted. The core is a dispersed phase of a dispersion liquid of the polymer, and T _g (glass transition temperature) is adjusted from a thermoplastic polymer having a temperature of 25 ° C. or less. The effect of the polymer for the core is as follows. And shows excellent fixability by preventing direct exposure to recording paper, thereby exhibiting good characteristics with respect to abrasion.

Examples of such a core monomer include ethyl methacrylate, ethyl acrylate and the like having 4 to 1 carbon atoms.
0 ester linear short methacrylate derivative, acrylate derivative, or styrene, a derivative of a substituted styrene derivative, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyvinyl butyral, rosin, tempel resin, phenol resin, fat Aromatic hydrocarbon resins, alicyclic hydrocarbon resins, and aromatic back-class resins are preferred. As is clear from the comparison with the monomer for shell, the solubility / insolubility in the oil-soluble medium depends on the length of the straight chain of the ester.

In this case, regarding the ratio of the resin composition of the resin particles formed by polymerization, the ratio of the monomer that is solvated with the non-aqueous medium, that is, the high insulating low dielectric constant carrier liquid, and the ratio of the non-solvated monomer, that is, It is necessary to set the amount of each monomer so that the ratio of the soluble monomer to the insoluble monomer is in the range of 60:40 to 95: 5 by weight.

Such conditions are conditions under which the resin particles are kept stable in the non-aqueous solvent, and are conditions under which the resin particles can easily be redispersed even if they settle. The solvation part is 60
When the content is less than 10% by weight, sedimentation of the resin becomes remarkable.
The unsolvated portions bind together and are not preferable from the viewpoint of re-dispersion of the ink. On the other hand, when the unsolvated portion is 5% by weight or less, the resin can only be solidified.

Next, a colorant is added to the above-mentioned resin particle dispersion, a high insulating low dielectric constant carrier liquid is added as a concentration adjusting solvent, and the mixture is dispersed using an attritor to prepare an oil-soluble ink for ink jet. I do. In this case, the coloring agent is bonded to the resin particles by hydrogen bonding with the monomer having the polar group or by adsorption by Van der Waals force, thereby forming colored resin particles.

As the coloring agent in this case, various pigments
It is possible to use a dye, for example, as an organic pigment, phthalocyanine blue, phthalocyanine green,
Rhodamine lake, peacock blue lake, sky blue, naphthol green B, naphthol green Y,
Naphthol Yellow S, Lisor First Yellow 2
G, Permanent Red 4R, Brilliant Fast Scarlet, Hanzai Yellow, Benzidine Yellow,
Examples include Lisor Red, Lake Red C, Lake Red D, Brilliant Carmine 6B, Permanent Red F5R, and the like. As the inorganic pigment, carbon black and the like can also be used.

As the dye, C.I. I. Solve
nt Yellow 2, C.I. I. Solvent Ye
llow14, C.I. I. Solvent Yellow
21, C.I. I. Solvent Black 5, C.I.
I. Solvent Black 22, C.I. I. Sol
vent Red3, C.I. I. Solvent Red
23, C.I. I. Solvent Red 49, C.I. I.
Solvent Blue 11, C.I. I. Solven
t Blue 25 or the like can be used, and oil-soluble dyes such as oil black and oil red, which are highly dispersible in resins, and dispersible dyes are effective.

By adding additives such as a surfactant and a dispersant as required, aggregation and sedimentation of the resin particles can be prevented.

The high-insulating low-dielectric-constant carrier liquid so that the total weight of the solid components, ie, the resin and the colorant, in the oil-soluble ink for ink-jet prepared as described above is 20% by weight or less of the whole ink. It is necessary to adjust the addition amount of the solid component. By setting the content to 20% by weight or less, a suitable viscosity can be obtained. This is inconvenient as an inkjet ink because of lack of properties.

Further, the oil-soluble ink for ink jet of the present invention provides a high color density, and a sufficient color density can be obtained even with a relatively low colorant concentration. Since effective color characteristics for mixing can be appropriately set according to the purpose, the weight ratio of the colorant to the solid component is 1 to 30% by weight.
Is desirable. Even if the concentration of the colorant is increased to 30% by weight or more, an obstacle such as saturation of the color density and reduction of the saturation occurs.

The diameter of the colored resin particles dispersed in the oil-soluble ink for ink jet of the present invention is preferably a filter having a pore size of 20 to 30 μm used for supplying the ink from the ink tank to the head portion. It is necessary to set the diameter so as not to cause clogging, and to set the average volume particle diameter (diameter) to 5 μm or less and not to include coarse particles of 10 μm or more.

By using such an oil-soluble ink for ink jet of the present invention, it is possible to perform a stable ejection even when the driving conditions are changed or the device is used for a long time, because the printed portion is excellent in abrasion resistance and water resistance. Thus, it is possible to provide an oil-soluble ink for inkjet which is excellent in long-term storage stability.

[0041]

EXAMPLES Next, the present invention will be described in more detail with reference to Examples and Comparative Examples. Before that, a method for evaluating an ink-jet oil-soluble ink will be described. Viscosity Using a parallel plate-type rotary viscometer, ○ indicates that the flow rate was 20 cps or less that did not affect the fluidity of the ink and ejection of small droplets, and X indicates that the flow rate was 20 cps or more. Average volume particle size Using a Galai average particle size distribution meter, if the average volume particle size is 5 μm or less that does not cause clogging of the head and does not include particles of 10 μm or more, 、, the average volume particle size is 5 μm or more or 10
If any of the conditions including particles of μm or more was satisfied, it was evaluated as x. Dispersion stability After each ink was prepared, it was allowed to stand at room temperature for 3 months, and the formation of a precipitate was visually observed. Ejection stability Each ink for ink jet is placed in an ink cartridge, mounted on an ink jet printer with a nozzle diameter of 40 μm and a resolution of 360 dpi, and plain paper for an electrophotographic copying machine is used as a recording medium. As a result of printing, if continuous printing of 10 sheets was possible, it was evaluated as ○.

Example 1 A 1000 cc flask equipped with a stirrer, a thermometer, a reflux condenser, and a dropping funnel was charged with 300 g of Isopar L (trade name, manufactured by Exxon) as a highly insulating and low dielectric constant medium and lauryl as a soluble monomer. 170 g of methacrylate, methacrylic acid 10 as a polar monomer
g, and azoisobutyronitrile 8 as a polymerization initiator
g was added dropwise over 1 hour and copolymerized at 80 ° C. for 6 hours. Next, 10 g of glycidyl methacrylate as an anchor monomer and 0.1 g of vinylpyridine as an esterification reaction catalyst were added, and
The ester reaction is carried out at 0 ° C. for 12 hours. Then
By adding 10 g of methyl methacrylate as an insoluble monomer to be a core and 2 g of azoisobutyronitrile as a polymerization initiator and copolymerizing at 80 ° C. for 4 hours, a polymerization rate of 99% and a resin concentration of 40% by weight were obtained. A resin dispersion is obtained.

Next, 35 g of this dispersion, 6 g of a naphthol-based magenta pigment (manufactured by Clariant) as a colorant,
60 g of Isopar L (trade name, manufactured by Exxon) was added as a concentration adjusting liquid, and the mixture was dispersed for 30 minutes using an attritor to prepare an oil-soluble ink for inkjet.

The composition of the ink of Example 1 is as follows: solvated part: unsolvated part = (170 + 10 + 10): 10 = 95: 5 solid content concentration = colored resin particles / ink = (35 × 0.4 + 6) / ( 35 + 6 + 60) = 20/101 ≒ 0.20 (20% by weight) Dye concentration = colorant / colored resin particles = 6 / (35 × 0.4 + 6) = 0.3 (30% by weight). In the above calculation of the composition ratio, the polymerization initiator and the esterification reaction catalyst were excluded. Continuous color printing was performed using this ink, and the above evaluation test was performed. As shown in FIG. 1, the viscosity, the average volume particle size,
Good results were obtained for all of dispersion stability and jetting stability, and high-quality color printing was obtained.

Next, Example 2 will be described. The other manufacturing conditions are the same as in Example 1 except that the amount of the starting material for preparing the resin dispersion is different. Description is omitted. The polymerization initiator and the esterification catalyst were used in the same manner as in Example 1. (Example 2) Isopar L (trade name of Exxon) 300 g Lauryl methacrylate 100 g Methacrylic acid 10 g Glycidyl methacrylate 10 g Methyl methacrylate 80 g A resin dispersion was prepared using the above substances as starting materials, and 35 g of this dispersion and a coloring agent were used. 6 g of a naphthol-based magenta pigment (manufactured by Clariant) and 60 g of Isopar L (trade name, manufactured by Exxon) as a concentration adjusting liquid were added, and the mixture was dispersed for 30 minutes using an attritor to prepare an oil-soluble ink for inkjet.

The composition of the ink of Example 2 is as follows: solvated part: unsolvated part = (100 + 10 + 10): 80 = 60: 40 solids concentration = (35 × 0.4 + 6) / (35 + 6 + 60) = 20/101 ≒ 0.20 (20% by weight) Dye concentration = 6 / (35 × 0.4 + 6) = 0.3 (30% by weight) Perform continuous color printing using this ink,
When the above evaluation test was performed, as shown in FIG. 1, good results were obtained for all of the viscosity, average volume particle size, dispersion stability, and jetting stability, and high-quality color recording was obtained. Was completed.

Next, Example 3 will be described. Since the other manufacturing conditions are the same as in Example 1 except that the amount of the coloring agent is different, detailed description of the manufacturing steps is omitted. The polymerization initiator and the esterification catalyst were used in the same manner as in Example 1. (Example 3) Isopar L (trade name of Exxon) 300 g Lauryl methacrylate 170 g Methacrylic acid 10 g Glycidyl methacrylate 10 g Methyl methacrylate 10 g A resin dispersion was prepared using the above substances as starting materials, and 40 g of this dispersion and a coloring agent were used. 0.1 g of a naphthol-based magenta pigment (manufactured by Clariant), 60 g of Isopar L (trade name, manufactured by Exxon) as a concentration adjusting liquid were added, and the mixture was dispersed for 30 minutes using an attritor to prepare an oil-soluble ink for inkjet. did.

The composition of the ink of Example 3 is as follows: solvated part: unsolvated part = (170 + 10 + 10): 10 = 95: 5 solids concentration = (40 × 0.4 + 0.1) / (40 + 0.1 + 60) = 16.1 / 100.1 @ 0.16 (16% by weight) Dye concentration = 0.1 / (40 x 0.4 + 0.1) $ 0.0062 @ 0.01 (1% by weight). Perform continuous color printing using this ink,
When the above evaluation test was performed, as shown in FIG. 1, good results were obtained for all of the viscosity, average volume particle size, dispersion stability, and jetting stability, and high-quality color recording was obtained. Was completed.

Next, Comparative Example 1 will be described. The other manufacturing conditions are the same as in Example 1 except that the amount of the starting material and the type of the colorant for preparing the resin dispersion are different.
Detailed description of the manufacturing process is omitted. The polymerization initiator and the esterification catalyst were used in the same manner as in Example 1. (Comparative Example 1) Isopar L (trade name of Exxon) 300 g Lauryl methacrylate 80 g Methacrylic acid 10 g Glycidyl methacrylate 10 g Methyl methacrylate 100 g A resin dispersion was prepared using the above substances as starting materials, and 35 g of this dispersion and a coloring agent were used. 6 g of azo type magenta dye (manufactured by Nippon Kayaku), Isopar L as a concentration adjusting solution
(Exxon Corp.) (60 g) was added and dispersed for 30 minutes using an attritor to prepare an oil-soluble ink for inkjet.

The composition of the ink of Example 1 is as follows: solvated part: unsolvated part = (80 + 10 + 10): 100 = 50: 50 solids concentration = (35 × 0.4 + 6) / (35 + 6 + 60) = 20/100 = 0.20 (20% by weight) Dye concentration = 6 / (35 × 0.4 + 6) = 0.30 (30% by weight).

Continuous color printing was performed using this ink, and the above evaluation test was performed. As shown in FIG. 1, although the viscosity was good, the average volume particle diameter, dispersion stability, and jetting Poor stability, clogging of the head, etc., hindered continuous color printing. This is the solvated part: unsolvated part = 50: 50, the unsolvated part,
That is, it is considered that the ratio of the core resin is too large, and the sedimentation of the resin particles becomes remarkable.

Next, Comparative Example 2 will be described. The other manufacturing conditions are the same as in Example 1 except that the composition ratio and the type of the coloring agent in the coloring step are different. Omitted. The polymerization initiator and the esterification catalyst were used in the same manner as in Example 1. (Comparative Example 2) Isopar L (trade name of Exxon) 300 g Lauryl methacrylate 170 g Methacrylic acid 10 g Glycidyl methacrylate 10 g Methyl methacrylate 10 g A resin dispersion was prepared using the above substances as starting materials, and 52 g of this dispersion and a coloring agent were used. 6 g of azo type magenta dye (manufactured by Nippon Kayaku), Isopar L as a concentration adjusting solution
(Exxon Co., Ltd.) (42 g) was added and dispersed for 30 minutes using an attritor to prepare an oil-soluble ink for inkjet.

The composition of the ink of Comparative Example 2 was as follows: solvated part: unsolvated part = (170 + 10 + 10): 10 = 95: 5 solid content concentration = (52 × 0.4 + 6) / (52 + 6 + 42) = 26.8 /100=0.268 (about 27% by weight) Dye concentration = 6 / (52 × 0.4 + 6) ≒ 0.224 (about 22% by weight).

Continuous color printing was performed using this ink, and the above-described evaluation test was performed. As shown in FIG. 1, since high viscosity and low fluidity make it difficult to discharge small droplets. Injection stability was also poor, and high-quality color recording could not be obtained. This means that the solids concentration is about 27
It is considered that the viscosity increased with the increase of the solid content concentration due to the high weight percent.

Next, Comparative Example 3 will be described. The other manufacturing conditions are the same as in Example 1 except that the composition ratio and the type of the coloring agent in the coloring step are different. Omitted. The polymerization initiator and the esterification catalyst were used in the same manner as in Example 1. (Comparative Example 3) Isopar L (trade name of Exxon) 300 g Lauryl methacrylate 170 g Methacrylic acid 10 g Glycidyl methacrylate 10 g Methyl methacrylate 10 g A resin dispersion was prepared using the above substances as starting materials, and 30 g of this dispersion and a coloring agent were used. 8 g of azo-based magenta dye (manufactured by Nippon Kayaku), Isopar L as a concentration adjusting solution
(Exxon Corp.) (60 g) was added and dispersed for 30 minutes using an attritor to prepare an oil-soluble ink for inkjet.

The composition of the ink of Comparative Example 3 was as follows: solvated part: unsolvated part = (170 + 10 + 10): 10 = 95: 5 solid content concentration = (30 × 0.4 + 8) / (30 + 8 + 60) = 20/98 ≒ 0.204 (20.4% by weight) Dye concentration = 8 / (30 × 0.4 + 8) = 0.40 (40% by weight).

Continuous color printing was performed using this ink, and the above-described evaluation test was performed. As shown in FIG. 1, the dispersion stability of the dyes deteriorated, and aggregation of the dyes was confirmed. The body volume particle size was not a satisfactory value, clogging occurred, and hindered continuous color printing. This is presumably because the dye concentration was as high as 40% by weight, so that the dispersion stability was reduced as the dye concentration was increased, and the chroma was also deteriorated as the dye concentration was increased.

The oil-soluble ink for ink-jet of the present invention has been described above. However, the oil-soluble ink for ink-jet of the present invention is not limited to a DOD type ink-jet printer, but is also used in a continuous jet type ink-jet printer. Things.

In the oil-soluble ink for ink jet of the present invention, since a non-aqueous solvent having a high insulating property and a low dielectric constant is used as a carrier liquid, the ink is not limited to a piezo type or bubble type, but may be an electrostatic acceleration type ink jet printer. Can also be used.

[0060]

According to the present invention, in an oil-soluble ink for ink jet, a colorant and a resin are dispersed in a non-aqueous solvent having a high insulating property and a low dielectric constant, and the resin has an affinity with a solvate having an affinity for a carrier liquid. Uses an amphiphilic resin composed of an acrylate derivative composed of a non-solvated part without insolubility, so it has excellent scratch resistance and water resistance of printed matter, and is stable against fluctuations in driving conditions and long-term use Discharge can be performed,
Since it is possible to provide an oil-soluble ink for inkjet which has excellent long-term storage stability, it greatly contributes to further spread of inkjet printers.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of evaluation results of an oil-soluble ink for ink jet.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Norio Saruwatari 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa Prefecture Inside Fujitsu Limited (72) Mitsuo Ozaki 4-1-1, Kamiodanaka, Nakahara-ku, Kawasaki-shi, Kanagawa No. 1 Fujitsu Limited F term (reference) 4J039 AD01 AD03 AD05 AD07 AD08 AD10 AD18 AD19 AE02 AF01 BC02 BC20 BE12 BE22 BE33 EA36 EA38 EA41 EA44 EA46 GA24

Claims (5)

[Claims] 1. An oil-soluble ink for ink-jet ink comprising a colorant, a resin, and a high-insulating, low-dielectric-constant carrier liquid as main components, wherein the resin has an affinity for the high-insulating, low-dielectric-constant carrier liquid. An oil-soluble ink for inkjet, comprising a solvated part having a non-solvated part and an unsolvated part having no affinity. 2. A resin having an affinity for a carrier liquid having a high insulating property and a low dielectric constant in the resin, wherein the carbon number of a monomer portion of the resin is 10 to 3;
0 at least one of an acrylate derivative or a methacrylate derivative, or
Acrylic ester derivative, methacrylic ester derivative, styrene, substituted styrene derivative having 4 to 10 carbon atoms in the monomer part of the resin having no affinity for the high insulating low dielectric constant carrier liquid in the resin. , Polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, polyvinyl butyral, rosin, tempel resin, phenolic resin, aliphatic hydrocarbon resin, alicyclic hydrocarbon resin, or aromatic resin The oil-soluble ink for inkjet according to claim 1, which satisfies at least one condition of at least one of the conditions. 3. The weight ratio of the monomer portion of the resin having affinity to the monomer portion of the resin having no affinity in the resin is 6%.
The oil-soluble ink for inkjet according to claim 1 or 2, wherein the ratio is in the range of 0:40 to 95: 5. 4. An average volume particle diameter of particles contained in the oil-soluble ink for ink-jet recording is 5 μm or less, and
The oil-soluble ink for inkjet according to any one of claims 1 to 3, wherein the oil-soluble ink does not contain coarse particles having a size of not less than μm. 5. The composition according to claim 1, wherein the total ratio of the resin and the colorant to the oil-soluble ink for inkjet is 20% by weight or less, or the ratio of the colorant to the total of the resin and the colorant is 1 to 30%. The oil-soluble ink for inkjet according to any one of claims 1 to 4, wherein at least one of the conditions is satisfied.