JP2015196731A - Oily ink composition for inkjet recording and inkjet recording method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oily ink composition for inkjet recording having print drying property in high-speed printing, image uniformity of a solid part, thin line image reproducibility, surface glossiness of a printed matter, abrasion resistance, high-speed printability, intermittent ejectability, printer member adequacy and maintainability.SOLUTION: There is provided an oily ink composition for inkjet recording which is an oily ink composition comprising a coloring material, a solvent and a binder resin, where the oily ink composition contains at least one of a lactone-based solvent and an amide-based solvent, the total amount of the solvent and the amide solvent is 10 to 40 mass% in the total solvents and the oily ink composition contains 3 to 20 mass% of a polyoxyalkylene glycol monoalkyl ether having a boiling point of 200 to 330°C in the total solvents.

Description

  The present invention relates to an oil-based ink composition for ink jet recording and an ink jet recording method.

  As an inkjet recording method, a method of discharging ink using an electrostatic attraction force (electric field control method), a method of discharging ink using a driving pressure of a piezo element (a drop-on-demand method or a pressure pulse method) In addition, there are various ink jet recording methods such as a method (bubble or thermal jet method) in which ink is ejected by using pressure generated by forming and growing bubbles by high heat. It is known that a highly accurate image can be obtained.

  As inks used in these ink jet recording methods, water-based inks using water as a main solvent and oil-based inks using an organic solvent as a main solvent are generally used. Printed images formed using water-based inks are generally poor in water resistance, and printing on recording media having a water-resistant surface is difficult, whereas oil-based inks provide print images with excellent water resistance. In addition, the oil-based ink using a pigment as a coloring material is excellent in light resistance, such as being easy to print on a recording medium having a water-resistant surface and high-quality paper.

  Conventionally, in oil-based inks, as organic solvents, aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as hexane and kerosene, ketones such as methyl ethyl ketone, esters such as ethyl acetate, or propylene glycol monomethyl ether Low boiling solvents such as acetate have been used, but when printing using inks made from these organic solvents, these organic solvents have low boiling points and flash points, and the nozzles are clogged due to excessively fast drying. There was a problem that it was easy. Further, there has been a problem that the cost of the printer specifications is high due to the solubility and swelling properties of the materials and plastics used in devices and parts such as ink storage containers and printers. Further, the printing quality when printing on a polyvinyl chloride substrate was not satisfactory.

Therefore, a technique has been developed in which an alkylene glycol dialkyl ether solvent having a higher boiling point, lower vapor pressure, and lower odor is used as an organic solvent for oil-based ink. For example, Patent Document 1 describes an oil-based ink composition for ink jet recording containing a specific amount of a mixed solvent containing a specific polyoxyethylene glycol dialkyl ether and a lactone solvent in a specific ratio and a coloring material. ing. According to Patent Document 1, it is described that the oil-based ink composition for ink-jet recording according to the technique is suitable for printing on a polyvinyl chloride substrate, and is excellent in print quality, print stability, print drying property, and ink storage stability. Has been.
Patent Document 2 discloses a non-aqueous ink for ink jetting containing an amide solvent composed of β-alkoxypropionamides and a copolymer containing vinyl chloride and vinyl acetate. According to Patent Document 2, it is described that the non-aqueous ink for ink jet according to the technology can firmly fix the ink on the surface of the recording medium containing the vinyl chloride resin, and is excellent in fixability and ejection stability. ing.

International Publication No. 2004/007626 Pamphlet JP 2013-18930 A

In recent years, there has been an increasing demand for high-speed and high-definition printing in an inkjet printer.
In recent years, “high density heads” have been developed in which the number of nozzles is two times higher than that of conventional inkjet heads. When such a high-density head is used, high-definition printing is possible, and at the same time, high-speed printing is possible, and high-density printing is also possible. Therefore, as an inkjet ink used in a printer having such a high-density head, high ejection responsiveness and ejection stability during intermittent ejection are required, and even during high-speed printing, the ink is ejected instantaneously, and , High-speed printing suitability that prevents ink scattering and landing position deviation, high image uniformity that does not cause unevenness and streaks in solid printing, and image reproducibility that does not cause blurring in fine line printing, etc. Related high demands are made. On the other hand, as the printing speed increases, it is demanded that high drying properties and a process after drying can be performed immediately.
In addition, as a recent trend of inkjet printers for oil-based inkjet inks, it has been practiced to use those developed for aqueous inkjet inks as inkjet heads. This is intended to reduce the cost of the printer by using an inkjet head for water-based inkjet that is mass-produced. However, ink jet heads for water-based ink jets are often developed without considering solvent resistance, and problems such as dissolution and swelling of the ink jet head member due to the solvent contained in the oil-based ink are likely to occur. In particular, when a low-boiling solvent is contained in order to increase the drying property, the above-mentioned problems tend to occur.
In addition, as a countermeasure for preventing clogging of the ink jet head, a printer including a system for performing a head cap at the time of a stoppage has become mainstream. The head cap is composed of a cap for covering the head and an absorbent member provided inside the cap, and the absorbent member is usually made of PVA. For this reason, the oil-based ink adheres and the absorbent member swells, and there is a case where the absorbent member comes into contact with the inkjet head.
Therefore, as an oil-based ink composition for ink-jet recording, it does not adversely affect the plastic or adhesive used in printer members such as ink-jet heads, and does not swell the absorbent member for head caps. For example, printer member suitability is also required.
Furthermore, in recent years, improvement in maintenance performance of inkjet printers has been demanded. Nozzles are difficult to clog even when the printer is used less frequently or left for a long time, etc., and it is required that the clogged nozzles can be cleaned to restore ejection, and inkjet printers equipped with a cleaning system have become the mainstream. ing. In the cleaning system, for example, a roller pump is operated at the time of cleaning, and ink is sucked from the ink jet head to eliminate ink clogging in the nozzle and the ink feeding tube. After cleaning, ink remains in a part of the ink feeding tube. However, when the ink is solidified, the cleaning system does not function such that ink cannot be sucked or waste liquid cannot be fed. The ink feeding tube is usually made of elastomer because it corresponds to a roller pump, but if the remaining ink solvent penetrates into the tube and volatilizes out of the tube, the fluidity of the ink in the tube decreases, or the ink flows. The problem of solidification occurs. For this reason, the maintainability of the oil-based ink composition for ink jet recording is suitable for a tube that does not easily clog ink in the ink feeding tube used in the printer, and the nozzle clogging is eliminated by cleaning even if the nozzle is clogged. Recoverability is required.
From the above, it is possible to maintain high dryness that is compatible with high-speed printing, excellent solid image uniformity and high-resolution image reproducibility that are compatible with high-definition printing, and high-definition printing as it is. Are required to have abrasion resistance, surface gloss of printed matter, high-speed printing suitability, intermittent discharge ability, printer member suitability, and maintenance ability.
However, even the inks described in Patent Document 1 and Patent Document 2 cannot satisfy all these requirements. Patent Document 1 also describes an example in which a specific polyoxyethylene glycol dialkyl ether, a lactone solvent, and a specific polyoxyethylene glycol monoalkyl ether are combined. However, in this technology, physical properties that tend to be a trade-off. It was difficult to obtain a material satisfying both the drying property and the surface glossiness of the printed material, or the reproducibility of fine lines and the uniformity of the solid portion at the same time.

  The present invention has been made in view of the above-described problems, and is intended to provide printing drying properties at high speed printing, solid image uniformity and image reproducibility of fine lines, surface glossiness of printed matter, abrasion resistance, and high-speed printing suitability. Ink jet recording oil-based ink composition having intermittent ejection properties, printer member suitability, and maintainability, print drying property in high-speed printing, solid image uniformity and fine lines using the ink-jet recording oil-based ink composition It is an object of the present invention to provide an ink jet recording method having image reproducibility, surface gloss of printed matter, abrasion resistance, high-speed printing suitability, intermittent ejection ability, printer member suitability, and maintenance ability.

The oil-based ink composition for inkjet recording according to the present invention is an oil-based ink composition containing a color material, a solvent, and a binder resin,
The solvent contains at least one of a lactone solvent and an amide solvent, the total amount of the lactone solvent and the amide solvent is 10 to 40% by mass in the total solvent, and the boiling point is 200 ° C. It is characterized by containing 3 to 20% by mass of polyoxyalkylene glycol monoalkyl ether at ˜330 ° C. in all solvents.
The oil-based ink composition for ink-jet recording according to the present invention contains at least one lactone solvent and amide solvent in a total amount of 10 to 40% by mass, and has a boiling point of 200 ° C. to 330 ° C. By containing 3-20% by mass of polyoxyalkylene glycol monoalkyl ether in all the solvents, print drying at high speed printing, solid image uniformity and image reproducibility of fine lines, surface gloss of printed matter, abrasion resistance And an oil-based ink composition for ink-jet recording having high performance, high-speed printing suitability, intermittent discharge ability, printer member suitability, and maintenance ability.

  In the oil-based ink composition for ink jet recording according to the present invention, the total amount of the lactone solvent and the amide solvent exceeds 2.0 parts by mass with respect to 1 part by mass of the polyoxyalkylene glycol monoalkyl ether solvent. In addition, the inclusion in a proportion of 6.0 parts by mass or less makes the solid image uniformity and the surface gloss of the printed material particularly excellent, and achieves both fine line image reproducibility and solid image uniformity. This is preferable from the viewpoint of achieving both the drying property, the abrasion resistance and the surface gloss of the printed matter.

  In the oil-based ink composition for ink-jet recording according to the present invention, the acrylic resin as the binder resin contains a discharge response that is compatible with high-speed printing, discharge stability during intermittent discharge, and a printed film. It is preferable from the viewpoint of excellent physical properties.

  The present invention also provides an ink jet recording method using the oil-based ink composition for ink jet recording according to the present invention.

  According to the present invention, print drying in high-speed printing, solid image uniformity and image reproducibility of fine lines, surface glossiness of printed matter, abrasion resistance, high-speed printing suitability, intermittent ejection properties, printer member suitability, Ink-jet recording oil-based ink composition with maintenance properties, and ink-jet recording oil-based ink composition using the above-described ink-jet recording oil-based ink composition, high-speed printing, dry image uniformity, solid line image reproducibility, surface gloss of printed matter Ink jet recording method having high performance, scratch resistance, high-speed printing suitability, intermittent ejection ability, printer member suitability, and maintenance ability can be provided.

  Hereinafter, the oil-based ink composition for ink-jet recording and the ink-jet recording method according to the present invention will be described in order.

1. Oil-based ink composition for ink-jet recording The oil-based ink composition for ink-jet recording according to the present invention is an oil-based ink composition containing a coloring material, a solvent and a binder resin,
The solvent contains at least one of a lactone solvent and an amide solvent, the total amount of the lactone solvent and the amide solvent is 10 to 40% by mass in the total solvent, and the boiling point is 200 ° C. It is characterized by containing 3 to 20% by mass of polyoxyalkylene glycol monoalkyl ether at ˜330 ° C. in all solvents.

The oil-based ink composition for ink jet recording according to the present invention contains at least one of a lactone solvent and an amide solvent, and the total amount of the lactone solvent and the amide solvent is 10 to 40% by mass in the total solvent. In addition, the polyoxyalkylene glycol monoalkyl ether having a boiling point of 200 ° C. to 330 ° C. is contained in an amount of 3 to 20% by mass in all the solvents, so that print drying in high-speed printing, solid image uniformity, and fine lines Ink jet recording oil-based ink compositions having excellent image reproducibility, surface glossiness of printed matter, abrasion resistance, high-speed printing suitability, intermittent ejection ability, printer member suitability, and maintenance ability.
In the oil-based ink composition for ink-jet recording according to the present invention, the action for obtaining the above-mentioned effect is considered as follows although there are unclear parts.
Since the lactone solvent and the amide solvent have particularly high penetrability with respect to a substrate mainly composed of a vinyl chloride polymer, the lactone solvent and the amide solvent improve the drying property and abrasion resistance of the print surface. On the other hand, lactone solvents and amide solvents are solvents having a relatively high boiling point, easily maintain the fluidity of the ink, and contribute to ejection response and intermittent ejection stability. Moreover, since it shows high solubility with respect to the resin used as a binder in the ink, there is an effect of eliminating nozzle clogging due to drying of the ink at the time of printing or idling.
However, lactone solvents and amide solvents are highly permeable to substrates made of vinyl chloride polymers and have a high effect of sharpening fine line images. In some cases, the permeability of the base material made of a polymer is excessively strong, unevenness is likely to occur, and it is difficult to increase the image uniformity of the solid portion. In addition, if the content of lactone solvents and amide solvents is increased, the ability to dissolve the substrate is strong, so the gloss of the surface of the printed material can be easily lost, and the adhesive used for the head (epoxy resin) In some cases, the suitability of printer members such as plastic and plastic deteriorated. In particular, problems are likely to occur in printers using the above-described aqueous inkjet ink head.

  On the other hand, by containing a specific amount of at least one of a lactone solvent and an amide solvent and a specific amount of polyoxyalkylene glycol monoalkyl ether having a specific boiling point, fast drying properties and excellent resistance While maintaining rubbing and intermittent ejection properties, wetting and spreading of ink is improved, white spots (filling defects) are less likely to occur, and solid image quality is improved, thereby preventing unevenness. . Furthermore, printer member suitability, maintainability, and surface gloss of printed matter are improved. The polyoxyalkylene glycol monoalkyl ether having the specific boiling point has a relatively slow volatilization and a relatively poor permeability to the printing surface made of a vinyl chloride polymer, so that it tends to remain on the substrate. It is estimated that the spreadability is improved, the above-described solid image uniformity is obtained, and the surface gloss of the printed matter is improved. In addition, since the polyoxyalkylene glycol monoalkyl ether is used by selecting a specific boiling point, it has excellent drying properties and excellent reproducibility of fine lines, while having fast drying properties and excellent abrasion resistance. It is excellent in both uniformity of the solid part. In addition, it is presumed that intermittent ejection properties can be maintained, and printer member suitability (head cap absorber) is also improved. In addition, by combining the polyoxyalkylene glycol monoalkyl ether having a specific boiling point with a specific amount, the volatility of the ink on the head surface becomes appropriate, and in particular, the effect of reducing ink scattering that is likely to occur during high-speed printing. It is estimated that there is.

The oil-based ink composition for ink-jet recording according to the present invention is an oil-based ink composition containing a coloring material, a solvent, and a binder resin, and may contain other components as necessary.
Hereinafter, the constituent components will be described in order.

<Solvent>
The solvent used in the ink composition of the present invention contains at least one of a lactone solvent and an amide solvent, and the total amount of the lactone solvent and the amide solvent is 10 to 40% by mass in the total solvent. And 3 to 20% by mass of polyoxyalkylene glycol monoalkyl ether having a boiling point of 200 ° C. to 330 ° C. in all the solvents.
(Lactone solvent)
The lactone solvent of the present invention is a cyclic ester compound, which means that a hydroxyl group and a carboxyl group in the molecule are dehydrated and condensed to form a cyclic structure. A compound having a 5- to 11-membered cyclic structure is preferable, and examples include γ-lactone having a 5-membered ring structure, δ-lactone having a 6-membered ring structure, and ε-lactone having a 7-membered ring structure. Examples of the lactone solvent include γ-butyrolactone, γ-valerolactone, γ-hexalactone, γ-heptalactone, γ-octalactone, γ-nonalactone, γ-decalactone, γ-undecalactone, and δ-valerolactone. , Δ-hexalactone, δ-heptalactone, δ-octalactone, δ-nonalactone, δ-decalactone, δ-undecalactone, and the like.

The lactone solvent is a solvent having a particularly high permeability to the printing surface mainly composed of a vinyl chloride polymer, and improves the print drying property, the image reproducibility of fine lines, and the abrasion resistance. In addition, lactone solvents have a relatively slow drying property and are difficult to volatilize, and also have the advantage of improving ink fluidity, ejection response, and intermittent ejection stability.
The lactone solvent has a boiling point of preferably 160 ° C. or higher, more preferably 180 ° C. or higher, particularly preferably 200 ° C. or higher, and preferably 280 ° C. or lower. This is because it is excellent in terms of improvement in print drying property, image reproducibility of fine lines, and abrasion resistance, improvement in ejection response, and intermittent ejection stability.

(Amide solvent)
The amide solvent of the present invention is a compound containing one carboxylic acid amide structure in the molecular structure and having an ether bond in the linear alkyl structure. In the present invention, an amide solvent represented by the following general formula (1) is preferably used.

（式中、Ｒ^１は炭素数１〜８のアルキル基であり、Ｒ^２及びＲ^３はそれぞれ独立に水素原子、炭素数１〜６のアルキル基、又は、炭素数１〜６のアルコキシアルキル基である。）

(In the formula, R ¹ is an alkyl group having 1 to 8 carbon atoms, and R ² and R ³ are each independently a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or an alkoxyalkyl group having 1 to 6 carbon atoms. .)

R ¹ is a linear or branched alkyl group having 1 to 8 carbon atoms. R ¹ is methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, sec-butyl group, t-butyl group, n-pentyl group, i-pentyl group. , Sec-pentyl group, t-pentyl group, n-hexyl group, i-hexyl group, sec-hexyl group, t-hexyl group, n-heptyl group, i-heptyl group, sec-heptyl group, t -Heptyl group, n-octyl group, i-octyl group, sec-octyl group, t-octyl group, and the like are mentioned. Among them, a linear or branched alkyl group having 1 to 4 carbon atoms is preferable, and methyl Group or various butyl groups are preferably used. The alkyl groups of R ² and R ³ are also linear or branched alkyl groups, and an alkyl group having 1 to 6 carbon atoms among the examples of R ¹ can be used. The alkoxyalkyl group having 1 to 6 carbon atoms of R ² and R ³ has a structure including an ether bond in a linear or branched alkyl group having 1 to 6 carbon atoms among the above alkyl groups. Examples thereof include methoxymethyl group and ethoxymethyl group. R ² and R ³ are preferably a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, or a t-butyl group, and more preferably a methyl group or an ethyl group. It is done.
Among them, in the amide solvent represented by the general formula (1), a combination in which R ¹ is a methyl group, R ² and R ³ are methyl groups, R ¹ is an n-butyl group, and R ² and R ³ are methyl groups. The combination which is is used suitably. These solvents have high penetrability into a printing surface mainly composed of a vinyl chloride polymer, and have good drying properties and abrasion resistance. Furthermore, since volatilization on the head surface is slow, ink fluidity, ejection response, and intermittent ejection stability can be improved.
The amide solvent represented by the general formula (1) can be produced, for example, with reference to the method described in International Publication No. 2008/102615 pamphlet. Examples of commercially available amide solvents represented by the general formula (1) include ecamide (trademarks, product numbers M100 and B100, Idemitsu Kosan Co., Ltd.).

The amide solvent also has high penetrability to the printing surface mainly composed of a vinyl chloride polymer, and improves dryness and abrasion resistance. On the other hand, the amide solvent is less likely to volatilize on the head surface, and has the advantage of improving ink fluidity, ejection response, and intermittent ejection stability.
The amide solvent preferably has a boiling point of 160 ° C. or higher, more preferably 180 ° C. or higher, particularly preferably 200 ° C. or higher, and preferably 280 ° C. or lower. This is because it is excellent in terms of improvement in print drying property, image reproducibility of fine lines, and abrasion resistance, improvement in ejection response, and intermittent ejection stability.

(Polyoxyalkylene glycol monoalkyl ether)
As the polyoxyalkylene glycol monoalkyl ether of the present invention, a polyoxyalkylene glycol monoalkyl ether having a boiling point of 200 ° C. to 330 ° C. is used so as to contain 3 to 20% by mass in all the solvents.
The polyoxyalkylene glycol monoalkyl ether having a specific boiling point has a hydroxyl group at the end, has a relatively slow volatilization, and has a relatively poor permeability to a printing surface made of a vinyl chloride polymer. Easy to remain in. Therefore, when the polyoxyalkylene glycol monoalkyl ether having the specific boiling point is used in combination with at least one of a lactone solvent and an amide solvent having high permeability to a printing surface made of a vinyl chloride polymer, In addition to image reproducibility of fine lines as described above, white spots (filling defects) are less likely to occur, and solid image uniformity is improved and printing unevenness is prevented. And the surface glossiness of printed matter is improved. When the polyoxyalkylene glycol monoalkyl ether having a specific boiling point is combined in a specific amount, the volatility of the ink on the head surface becomes appropriate, and in particular, there is an effect of reducing ink scattering that is likely to occur during high-speed printing.

  In particular, the polyoxyalkylene glycol monoalkyl ether having a boiling point of 200 ° C. to 330 ° C. preferably has a boiling point of 220 ° C. or higher, preferably 300 ° C. or lower, and more preferably 280 ° C. or lower. . When the boiling point is equal to or higher than the lower limit, it is difficult for the ink to volatilize from the liquid feeding tube, the ink fluidity is maintained, and there is no adverse effect on the ink liquid feeding tube in the cleaning system, and no adverse effect on the intermittent ejection property. It is possible to improve the image uniformity of the solid portion and the surface gloss of the printed matter. On the other hand, when the boiling point is below the upper limit, the image reproducibility of fine lines is improved without deteriorating the image reproducibility of fine lines, the suitability of printer members (head cap absorber), the drying property, and the abrasion resistance. can do. If the boiling point is less than the lower limit, the amount of solvent that volatilizes from the liquid supply tube increases, and ink gelation and solidification are likely to occur, which increases the frequency of cleaning and tends to cause problems with the cleaning system. . Further, when the boiling point exceeds the upper limit, the hydrophilicity of the polyoxyalkylene glycol monoalkyl ether tends to be strong, and the head cap absorbent body (PVA) is likely to swell. Moreover, it becomes easy to deteriorate print drying property and abrasion resistance.

  The above polyoxyalkylene glycol monoalkyl ether having a specific boiling point deteriorates with respect to printer members, for example, adhesives (epoxy resins, etc.) used for inkjet heads, plastic members, and head cap absorbers (PVA, etc.). In particular, even a printer member using a water-based inkjet printer head that is easily affected by a solvent is difficult to be deteriorated or deformed. Among them, the lactone solvents and amide solvents, and polyoxyalkylene glycol dialkyl ethers may adversely affect adhesives (epoxy resins) and plastic members used in inkjet heads. When the polyoxyalkylene glycol monoalkyl ether is combined, it is difficult to affect the adhesive (epoxy resin) and the plastic member used in the inkjet head. In addition, since the ink feeding tube (elastomer) in the cleaning system has a low property of permeating and volatilizing, the fluidity of the ink and the solidification of the ink hardly occur, and the maintenance performance is improved.

  Specific examples of the polyoxyalkylene glycol monoalkyl ether having a boiling point of 200 ° C. to 330 ° C. include, for example, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, diethylene glycol monohexyl ether, diethylene glycol mono 2-ethylhexyl ether, triethylene glycol Ethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol monopropyl ether, triethylene glycol mono n-butyl ether, dipropylene glycol monopropyl ether, dipropylene glycol monobutyl ether, tripropylene glycol monomethyl ether, tripropylene glycol mono Butyl ether Etc., and the like. Among them, one kind selected from the group consisting of diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, and triethylene glycol monobutyl ether from the viewpoint of excellent solid image uniformity, surface gloss of printed matter, and printer member suitability. The above is preferable.

In this invention, 3-20 mass% of polyoxyalkylene glycol monoalkyl ether is contained in all the solvents.
When the content is above the lower limit, the ink feeding tube suitability and intermittent discharge performance in the cleaning system are improved, the effect of spreading wet on the substrate is increased, and the solid image uniformity and surface gloss of the printed matter are improved. Can be improved. In addition, since there is no solubility in the adhesive used in the head, there is an effect of reducing the influence of the ink on the adhesive. On the other hand, when the content is less than or equal to the upper limit, the image uniformity of the solid portion is not deteriorated without deteriorating the suitability of the printer member (head cap absorber), drying property, abrasion resistance, and fine line image reproducibility. The surface gloss of the printed material can be improved.
In particular, the polyoxyalkylene glycol monoalkyl ether is preferably contained in 3 to 10% by mass in all the solvents. If it is within the above range, it is excellent in ejection responsiveness, drying property, and maintainability, and from the viewpoint of printer member suitability (adhesive for head and plastic member and absorber for head cap) and solid image uniformity. It is because it is preferable.

  The oil-based ink composition of the present invention contains at least one of a lactone solvent and an amide solvent, the total amount of the lactone solvent and the amide solvent is 10 to 40% by mass in the total solvent, and The polyoxyalkylene glycol monoalkyl ether having a boiling point of 200 ° C. to 330 ° C. is contained in 3 to 20% by mass in all the solvents. In particular, the total content of the lactone solvent and the amide solvent is preferably 10 to 30% by mass in the total solvent. If the total content of the lactone solvent and the amide solvent is too large, the solvent may dissolve on the printed surface, resulting in a decrease in gloss and stickiness, and a decrease in printer member suitability. , Fine line image reproducibility, rubbing resistance, intermittent ejection property, and maintainability may be inferior. When combined with at least one of a lactone solvent and an amide solvent, if the polyoxyalkylene glycol monoalkyl ether content is too high, the solvent will not easily penetrate into the raw material. May be inferior, and printer member suitability (head cap absorber) may be inferior. On the other hand, if the amount is too small, solid image uniformity, gloss, intermittent ejection property, printer member suitability (head adhesive) and There is a risk of poor maintenance.

  In the oil-based ink composition of the present invention, the total amount of the lactone solvent and the amide solvent exceeds 2.0 parts by mass with respect to 1 part by mass of the polyoxyalkylene glycol monoalkyl ether solvent, and Containing at a ratio of 0 part by mass or less makes the solid image uniformity and the surface gloss of the printed matter particularly excellent, and it is compatible with the image reproducibility of fine lines and the solid image uniformity, and drying. Is preferable from the standpoint of achieving both the properties and abrasion resistance and the surface gloss of the printed matter.

(Other solvents)
Examples of solvents other than lactone solvents, amide solvents, and polyoxyalkylene glycol monoalkyl ethers (hereinafter sometimes referred to as other solvents) include those conventionally used in oil-based ink compositions for ink jet recording. It can be appropriately selected and used as the main body. Other solvents may be used in combination of two or more.
Among these, it is preferable to use those having a boiling point of 140 ° C. or more from the viewpoint of ink ejection stability. On the other hand, those having a boiling point of 310 ° C. or less are preferable from the viewpoint of the drying property of the ink.
Other solvents are preferably polyoxyalkylene glycol dialkyl ethers, glycol alkyl ether acetates, glycols, etc. from the viewpoint of ejection stability. Among them, polyoxyalkylene glycol dialkyl ethers are preferred from the viewpoint of ejection stability. Used for.

As polyoxyalkylene glycol dialkyl ethers, polyoxyethylene glycol dialkyl ether represented by the following general formula (2) and polyoxypropylene glycol dialkyl ether represented by the following general formula (3) are preferably used.
General formula (2)
R ⁴ —O— (C ₂ H ₄ —O) _n —R ⁵
(In the formula, R ⁴ and R ⁵ are each independently an alkyl group having 1 to 4 carbon atoms, and n is an integer of 1 to 4).
General formula (3)
R ⁶ —O— (C ₃ H ₆ —O) _m —R ⁷
(In the formula, R ⁶ and R ⁷ are each independently an alkyl group having 1 to 4 carbon atoms, and m is an integer of 1 to 3).

R ⁴ and R ⁵ in the polyoxyethylene glycol dialkyl ether represented by the general formula (2), and R ⁶ and R ⁷ in the polyoxypropylene glycol dialkyl ether represented by the general formula (3) are each independently , A linear or branched alkyl group having 1 to 4 carbon atoms. Examples of R ⁴ and R ⁵ , and R ⁶ and R ⁷ include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, and a t-butyl group.

Examples of the polyoxyethylene glycol dialkyl ether represented by the general formula (2) include ethylene glycol diethyl ether, diethylene glycol dimethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl propyl ether, diethylene glycol methyl butyl ether, diethylene glycol diethyl ether, and diethylene glycol ethyl propyl ether. , Diethylene glycol ethyl butyl ether, diethylene glycol dipropyl ether, diethylene glycol propyl butyl ether, diethylene glycol dibutyl ether, triethylene glycol dimethyl ether, triethylene glycol methyl ethyl ether, triethylene glycol methyl propyl ether Triethylene glycol methyl ether, triethylene glycol diethyl ether, triethylene glycol ethyl propyl ether, triethylene glycol ethyl ether, triethylene glycol dibutyl ether, tetraethylene glycol dimethyl ether, tetraethylene glycol diethyl ether, and the like.
Examples of the polyoxypropylene glycol dialkyl ether represented by the general formula (3) include propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, dipropylene glycol diethyl ether, dipropylene glycol ethyl methyl ether, and dipropylene glycol butyl methyl ether. , Tripropylene glycol dimethyl ether, tripropylene glycol diethyl ether and the like.

  The polyoxyethylene glycol dialkyl ether represented by the general formula (2) and the polyoxypropylene glycol dialkyl ether represented by the general formula (3) have a boiling point of 140 ° C. or higher from the viewpoint of ink ejection stability. Are preferably used. On the other hand, those having a boiling point of 310 ° C. or less are preferable from the viewpoint of the drying property of the ink. Among them, from the viewpoint of ink ejection stability when combined with at least one of the specific amount of lactone solvent and amide solvent, and the specific amount of polyoxyalkylene glycol monoalkyl ether having a boiling point of 200 ° C. to 330 ° C. It is preferable to use those having a boiling point of 170 ° C. or higher. From the viewpoint of ink drying properties, it is preferable to use those having a boiling point of 230 ° C. or lower.

  As the polyoxyethylene glycol dialkyl ether represented by the general formula (2), at least one selected from the group consisting of diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, and diethylene glycol methyl isopropyl ether is preferably used.

Other solvents other than polyoxyalkylene glycol dialkyl ethers include, for example, glycols such as ethylene glycol, diethylene glycol, dipropylene glycol, ethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monomethyl ether acetate, diethylene glycol mono Glycol alkyl ether acetates such as ethyl ether acetate, diethylene glycol monobutyl ether acetate, propylene glycol monomethyl ether acetate, dipropylene glycol monomethyl ether acetate, glycol ethers such as ethylene glycol monobutyl ether and propylene glycol monobutyl ether, Le, hexyl acetate, octyl acetate, methyl lactate, ethyl lactate, propyl lactate, esters such as butyl lactate; methyl ethyl ketone, ketones such as cyclohexanone, dioxane, cyclohexane, beta-lactams and propylene carbonate. Among them, from the viewpoint of ink ejection stability when combined with at least one of the specific amount of lactone solvent and amide solvent, and the specific amount of polyoxyalkylene glycol monoalkyl ether having a boiling point of 200 ° C. to 330 ° C. It is preferable to use those having a boiling point of 170 ° C. or higher. From the viewpoint of ink drying properties, it is preferable to use those having a boiling point of 230 ° C. or lower.
As said other solvent, it is preferable to contain in the range of 40-87 mass% in all the solvents, and it is preferable that it is 50-75 mass% in all the solvents especially.

The mixed solvent used in the oil-based ink composition of the present invention is preferably adjusted to have a viscosity at 20 ° C. of 1 to 8 mPa · s, preferably 3 to 6 mPa · s as a whole. In the present invention, the viscosity is measured with a falling ball viscometer (for example, “AMVn” viscometer manufactured by Anton Paar).
In consideration of drying of the ink from the head surface, the vapor pressure at 20 ° C. is preferably 1 hPa or less, and more preferably 0.7 hPa or less.
By using such a mixed solvent, discharge responsiveness and maintainability are improved, the burden of providing local exhaust equipment or exhaust gas treatment equipment is reduced, the work environment can be improved, and the surrounding environment can be improved. Environmental load can be reduced.

<Color material>
As the coloring material, pigments such as inorganic pigments or organic pigments usually used in conventional oil-based ink compositions, and dyes can be used alone or in combination. Carbon black, cadmium red, molybdenum red, chrome yellow, cadmium yellow, titanium yellow, chromium oxide, viridian, titanium cobalt green, ultramarine blue, Prussian blue, cobalt blue, diketopyrrolopyrrole, anthraquinone, benzimidazo Ron, anthrapyrimidine, azo pigment, phthalocyanine pigment, quinacridone pigment, isoindolinone pigment, dioxazine pigment, selenium pigment, perylene pigment, perinone pigment, thioindigo pigment, quinophthalone pigment, titanium oxide or Metal complex pigments and the like can be used. Examples of the dye include azo dyes, metal complex dyes, naphthol dyes, anthraquinone dyes, indigo dyes, carbonium dyes, quinoneimine dyes, xanthine dyes, cyanine dyes, quinoline dyes, nitro dyes, nitroso dyes, benzoquinone dyes, naphthoquinone dyes, phthalocyanine A dye or a metal phthalocyanine dye can be used, and an oil-soluble dye is particularly preferable. Although these pigments or dyes can be used alone or in combination of two or more thereof, pigments are preferred from the viewpoint of weather resistance. The volume average particle diameter of the primary pigment particles is 10 to 500 nm, preferably 15 to 300 nm.

  As specific examples of the above-mentioned pigments, for example, when organic pigments are exemplified by color index (CI) numbers, C.I. I. Pigment Yellow 1, 2, 3, 12, 13, 14, 16, 17, 20, 24, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 117, 120, 125, 128, 129, 130, 137, 138, 139, 147, 148, 150, 151, 153, 154, 155, 166, 168, 180, 185, 213, 214; I. Pigment Red 5, 7, 9, 12, 48, 49, 52, 53, 57, 97, 112, 122, 123, 146, 149, 168, 177, 179, 180, 184, 192, 202, 206, 209, 215, 216, 217, 220, 223, 224, 226, 227, 228, 238, 240, 254, 272; I. Pigment orange 16, 36, 43, 51, 55, 59, 61, 64, 71; C.I. I. Pigment violet 19, 23, 29, 30, 37, 40, 50; C.I. I. Pigment Blue 15, 15: 1, 15: 3, 15: 4, 15: 6, 16, 22, 60, 64; C.I. I. Pigment green 7, 36, 58; I. Pigment brown 23, 25, 26; I. Pigment white 6 and the like.

<Binder resin>
The binder resin is not particularly limited. For example, acrylic resin, vinyl chloride polymer, vinyl chloride-vinyl acetate copolymer, ethylene-vinyl acetate copolymer, cellulose acetate butyrate, polyester resin, urethane resin. A rosin-modified resin, a phenol resin, a terpene resin, a polyamide resin, an epoxy resin, a vinyltoluene-α-methylstyrene copolymer, or a mixture thereof can be used.
In the present invention, an acrylic resin is preferably used as the binder resin from the viewpoint of improving the discharge response at the time of high-speed printing. On the other hand, it is preferable to contain a copolymer containing vinyl chloride and vinyl acetate from the viewpoint of improving the gloss, rubbing resistance and alcohol resistance of the printed surface. Moreover, it is preferable to contain the copolymer containing vinyl chloride and vinyl acetate which are easy to wet and spread on a vinyl chloride base material from the viewpoint that ink droplets are likely to be granular by containing a lactone solvent. From the point that it has ejection response at the time of high-speed printing and has excellent gloss, scratch resistance and alcohol resistance on the printed surface, as a binder resin, a copolymer containing acrylic resin, vinyl chloride and vinyl acetate, It is preferable to use together.

(acrylic resin)
The acrylic resin used in the present invention refers to a polymer compound including a polymer using at least one selected from acrylic acid, methacrylic acid and derivatives thereof as a monomer. The acrylic resin may further contain a structural unit derived from a compound having an ethylenic double bond polymerizable with acrylic acid, methacrylic acid and derivatives thereof.
In the present invention, by combining the mixed solvent with an acrylic resin as a binder resin, as described above, it is difficult for the viscosity to increase during volatilization, the clogging of the nozzle portion of the inkjet head is suppressed, and the surface of the head and Ink can be easily wiped at the time of cleaning the periphery, high ejection responsiveness at high-speed printing can be realized, and the droplet shape after ejection becomes good, so that ink scattering and landing position deviation are less likely to occur.
Moreover, by using an acrylic resin as the binder resin, the adhesiveness after printing is suppressed, and the set-off and sticking after winding and drying can be prevented.

Among them, the acrylic resin used in the present invention has good compatibility with the mixed solvent, and radical polymerization in a polyoxyalkylene glycol dialkyl ether solvent from the point that an acrylic resin solution of the mixed solvent can be easily prepared. It is preferable to use an acrylic resin obtained by solution polymerization using an initiator.
When an acrylic resin obtained by solution polymerization using a radical polymerization initiator in a polyoxyalkylene glycol dialkyl ether solvent is used, the acrylic resin has a reaction product having a solvent bonded to the terminal, and thus the mixed solvent The amount of the acrylic resin added can be increased, and the print drying property is improved and the re-dissolution property is improved.

The acrylic resin is preferably a radical polymerizability selected from the group consisting of alkyl methacrylates, aralkyl methacrylates, alkoxyalkyl methacrylates, hydroxyalkyl methacrylates, methacrylic acid, and dialkylaminoalkyl methacrylates. It can be obtained from the monomer. It has at least one radically polymerizable ethylenic double bond in the molecule, preferably one radically polymerizable ethylenic double bond in the molecule, and in the presence of a radical polymerization initiator in a solvent described later. Various monomers can be further used as long as they are polymerizable radically polymerizable monomers. For example, a vinyl compound or maleimide may be included as a radical polymerizable monomer.
The acrylic resin may be a homopolymer of one kind of radically polymerizable monomer, or may be any copolymer obtained by selecting two or more kinds of radically polymerizable monomers.

Examples of the radical polymerizable monomer used for the acrylic resin include (meth) acrylic acid, methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid-n-propyl, (meth) acrylic acid- iso-propyl, (meth) acrylic acid-n-butyl, (meth) acrylic acid-sec-butyl, (meth) acrylic acid-iso-butyl, (meth) acrylic acid-tert-butyl, (meth) acrylic acid pentyl , Neopentyl (meth) acrylate, hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, (meth) acrylic acid-iso-octyl, nonyl (meth) acrylate, ( (Meth) acrylic acid-iso-nonyl, dodecyl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate , (Meth) acrylic acid cyclopentyl, (meth) acrylic acid cyclohexyl, (meth) acrylic acid-2-methylcyclohexyl, (meth) acrylic acid dicyclopentanyl, (meth) acrylic acid dicyclopentenyloxyethyl, (meth) Dicyclohexyl acrylate, isobornyl (meth) acrylate, adamantyl (meth) acrylate, allyl (meth) acrylate, propargyl (meth) acrylate, phenyl (meth) acrylate, naphthyl (meth) acrylate, (meth) acrylic Anthracenyl acid, Anthraninon (meth) acrylate, Piperonyl (meth) acrylate, Salicyl (meth) acrylate, Furyl (meth) acrylate, Furfuryl (meth) acrylate, Tetrahydrofuryl (meth) acrylate, (Metal ) Acrylic acid tetrahydride Furfuryl, pyranyl (meth) acrylate, benzyl (meth) acrylate, phenethyl (meth) acrylate, cresyl (meth) acrylate, glycidyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate glycidyl ether, (meta ) Acrylic acid-3,4-epoxycyclohexylmethyl, (meth) acrylic acid-3,4-epoxycyclohexylethyl, (meth) acrylic acid-1,1,1-trifluoroethyl, (meth) acrylic perfluoro Ethyl, perfluoro-n-propyl (meth) acrylate, perfluoro-iso-propyl (meth) acrylate, heptadecafluorodecyl (meth) acrylate, triphenylmethyl (meth) acrylate, (meth) acrylic acid Cumyl, 3- (N, N-dimethyla) (meth) acrylic acid No) propyl, (meth) acrylic acid-2-hydroxyethyl, (meth) acrylic acid-2-hydroxypropyl, (meth) acrylic acid-2,3-dihydroxypropyl, (meth) acrylic acid-4-hydroxybutyl, Methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, 2-cyanoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate (Meth) acrylic acid such as (meth) acrylic acid trimethoxysilylpropyl, (meth) acrylic acid triethoxysilylpropyl, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldimethoxysilane and (meth) Acrylic esters;
(Meth) acrylic acid amide, (meth) acrylic acid N, N-dimethylamide, (meth) acrylic acid N, N-diethylamide, (meth) acrylic acid N, N-dipropylamide, (meth) acrylic acid N, N-di-iso-propylamide, (meth) acrylic acid butyramide, (meth) acrylic acid stearylamide, (meth) acrylic acid cyclohexylamide, (meth) acrylic acid phenylamide, (meth) acrylic acid benzylamide, (meth ) (Meth) acrylic amides such as acrylic anthracenyl amide;
Styrene, α-, o-, m-, p-alkyl of styrene, nitro, cyano, amide, ester derivatives, (meth) acrylic acid anilide, (meth) acryloylnitrile, acrolein, vinyl chloride, vinylidene chloride, vinyl fluoride Vinyl compounds such as vinylidene fluoride, N-vinyl pyrrolidone, vinyl pyridine, N-vinyl carbazole, vinyl imidazole and vinyl acetate;
Monomaleimides such as N-benzylmaleimide, N-phenylmaleimide, N-cyclohexylmaleimide, N-laurinmaleimide, N- (4-hydroxyphenyl) maleimide; and phthalimides such as N- (meth) acryloylphthalimide Can do. “(Meth) acryl” means both “acryl” and “methacryl”.

  A particularly preferred acrylic resin is a polymer of methyl methacrylate alone or a copolymer of methyl methacrylate and at least one compound selected from the group consisting of butyl methacrylate, ethoxyethyl methacrylate, and benzyl methacrylate. It is a coalescence. In the copolymer, the total amount of at least one compound selected from the group consisting of methyl methacrylate, butyl methacrylate, ethoxyethyl methacrylate, and benzyl methacrylate with respect to 100 parts by mass of methyl methacrylate is preferable. Is 0.01 to 15 parts by mass, more preferably 0.1 to 15 parts by mass, and still more preferably 0.5 to 12 parts by mass. Such an acrylic resin can provide an oil-based ink composition for ink-jet recording, which exhibits good compatibility with a solvent in the ink, and has ink storage stability and image reproducibility.

  The acrylic resin used in the present invention preferably has a mass average molecular weight of 5,000 to 100,000. In the present invention, the mass average molecular weight is a value measured with a gel permeation chromatograph (GPC) using polystyrene as a standard (for example, “HLC-8220GPC” manufactured by Tosoh Corporation). Among these, the acrylic resin used in the present invention preferably has a mass average molecular weight of 10,000 or more, and preferably 12,000 or more, from the viewpoint of abrasion resistance and easy tendency to prevent ink set-off after winding up the printed matter. Is more preferably 15000 or more. On the other hand, the acrylic resin used in the present invention is preferably 50000 or less, more preferably 35000 or less, and even more preferably 30000 or less, from the viewpoint of high discharge stability during high-speed printing.

  The acrylic resin used in the present invention preferably has a glass transition temperature (Tg) of 80 ° C. or higher and 110 ° C. or lower. In the present invention, the glass transition temperature (Tg) is a value measured by a differential scanning calorimeter (DSC) (for example, a differential scanning calorimeter “DSC-50” manufactured by Shimadzu Corporation). Although a plurality of glass transition temperatures may be observed, in the present invention, a main transition temperature having a larger endothermic amount is adopted. Moreover, when Tg is within the above range, the effect of obtaining good print drying properties becomes remarkable.

  The radical polymerization initiator used in the production of the acrylic resin used in the present invention is preferably an organic peroxide, hydroperoxide, dialkyl peroxide, peroxyester, diacyl peroxide, peroxycarbonate. -Based, peroxyketal-based, and ketone peroxide-based organic peroxides. Among them, dialkyl peroxide-based, peroxyester-based, and diacyl peroxide-based organic peroxides are preferable. This is because, as described above, since the solvent can have a reaction product bonded to the terminal, the compatibility of the acrylic resin with the solvent of the ink can be improved. Preferred specific examples include, but are not limited to, t-butylperoxy-2-ethylhexanoate, t-butyl hydroperoxide, di-t-hexyl peroxide and the like.

  Examples of commercially available (meth) acrylic resins include Rohm and Haas “Paralloid B99N” (methyl methacrylate / butyl methacrylate copolymer) Tg 82 ° C., mass average molecular weight 15,000), “Paralloid B60” ( Methyl methacrylate / butyl methacrylate copolymer) Tg 75 ° C., mass average molecular weight 50,000) and the like.

(Copolymer containing vinyl chloride and vinyl acetate)
The oil-based ink composition of the present invention preferably contains a copolymer containing vinyl chloride and vinyl acetate from the viewpoint of improving print drying properties and gloss, rubbing resistance and alcohol resistance of the printed surface. . The copolymer containing vinyl chloride and vinyl acetate may be provided with other structural units as needed together with vinyl chloride units and vinyl acetate units, such as carboxylic acid units, vinyl alcohol units, hydroxyalkyl acrylate units, etc. May be provided. The copolymer containing vinyl chloride and vinyl acetate preferably has a number average molecular weight of 10,000 to 50,000, more preferably 15,000 to 35,000, from the viewpoint of ejection stability, abrasion resistance and alcohol resistance. Is more preferable, and it is more preferable that it is 20000-30000. Here, the number average molecular weight is a value measured by GPC and converted to polystyrene.
As the copolymer containing vinyl chloride and vinyl acetate, those containing 70 to 90% by mass of vinyl chloride units in the copolymer are preferably used from the viewpoint of excellent maintenance and good image reproducibility. If the vinyl chloride unit is less than 70% of the copolymer, the abrasion resistance may decrease. On the other hand, if it exceeds 94% by mass, the gloss of the printed surface may be lowered.

In addition, for the purpose of improving the ejection response at the time of high-speed printing and the gloss, scratch resistance and alcohol resistance of the printed surface, the binder resin in the oil-based ink composition of the present invention includes an acrylic resin, vinyl chloride, and In the case where both the vinyl acetate-containing copolymer and the vinyl acetate / vinyl acetate-containing copolymer are contained, the viscosity during volatilization is likely to increase. In addition, an increase in viscosity and drying on the head surface may cause problems in ejection performance, and nozzle clogging and solidification in a liquid feeding tube may occur due to long-term use. Therefore, in this case, the content of the copolymer containing vinyl chloride and vinyl acetate is preferably 4 parts by mass or less and more preferably 1.5 parts by mass or less with respect to 1 part by mass of the acrylic resin. More preferably, it is 1 mass part or less. Moreover, it is preferable that it is 0.1 mass part or more from a dry point.
In addition, when the ink composition contains at least one of a lactone solvent and an amide solvent in terms of gloss on the printed surface, the dots tend to shrink and become grainy during the drying process of the ink. It is difficult to increase the uniformity. In the present invention, a lactone having improved permeability and drying properties by using a copolymer containing polyoxyalkylene glycol monoalkyl ether in the solvent and an acrylic resin, vinyl chloride and vinyl acetate in the binder resin. Even in an ink composition using at least one of a solvent and an amide solvent, the effect of improving the image uniformity of the solid portion is enhanced. In particular, a polyvinyl chloride base material is preferably used because its effect can be obtained more from the high affinity of the base material and the copolymer containing vinyl chloride and vinyl acetate in the binder resin.

  Examples of the vinyl chloride vinyl acetate copolymer resin include vinyl chloride vinyl acetate copolymer, vinyl chloride / vinyl acetate / maleic acid copolymer, vinyl chloride / vinyl acetate / vinyl alcohol copolymer, vinyl chloride / And vinyl acetate / hydroxyalkyl acrylate copolymers, and mixtures thereof. As the above-mentioned vinyl chloride vinyl acetate copolymer resin, “Solvine C (number average molecular weight (Mn), 31000), CL (Mn, 25000), CNL (Mn, 12000), CLL (Mn, 18000), C5R (Mn, 27000), TA2 (Mn, 33000), TA3 (Mn, 24000), A (Mn, 30000), AL (Mn, 22000), TA5R (Mn, 28000), M5 It can be obtained under a trade name such as (Mn, 32000) and used in the present invention.

<Other ingredients>
The oil-based ink composition for ink-jet recording according to the present invention can contain other components as necessary in addition to the above-described essential components. Examples of other components that can be included as necessary include a dispersant, a surfactant, and other various additives.

(Dispersant)
As the dispersant, any dispersant used in the oil-based ink composition for ink jet recording can be used. As the dispersant, a polymer dispersant is preferably used. As such a dispersant, the main chain is made of polyester, polyacrylic, polyurethane, polyamine, polycaprolactone, etc., and has a polar group such as amino group, carboxyl group, sulfone group, hydroxyl group as a side chain. It is. Examples of the polyacrylic dispersant include Disperbyk-2000, 2001, 2008, 2009, 2010, 2020, 2020N, 2022, 2025, 2050, 2070, 2095, 2150, 2151, 2155, 2163, 2164, BYKJET-9130, 9131. 9132, 9133, 9151 (Bic Chemie). In the polycaprolactone-based dispersant, for example, Azisper PB821, PB822, PB881 (manufactured by Ajinomoto Fine Techno Co., Ltd.) is used. A preferable dispersant is a polyester-based dispersant, for example, Hinoact KF-1000, T-6000, T-7000, T-8000, T-8000E, T-9050 (manufactured by Kawaken Fine Chemical Co., Ltd.), Solsperse 20000, 24000, 32000, 32500, 32550, 32600, 33000, 33500, 34000, 35200, 36000, 37500, 39000, 71000 (manufactured by Lubrizol), Florene DOPA-15BHFS, 17HF, 22, G-700, 900, NC-500 , GW-1500 (manufactured by Kyoeisha Chemical Co., Ltd.), Efka 4310, 4320, 4330, 4401, 4402, 4403N, 4570, 7411, 7477, 7700 (manufactured by BASF) or a mixture thereof It is possible to use the thing.

(Surfactant)
Further, in the oil-based ink composition for ink-jet recording of the present invention, for the purpose of suppressing volatilization of the oil-based ink composition in equipment such as the nozzle part and the tube, preventing solidification, and re-solubility when solidified, In addition to the mixed solvent, a liquid nonionic polyoxyethylene derivative may be added at room temperature and atmospheric pressure. For example, nonionic P-208, P-210, P-213, E-202S, E-205S, E-215, K-204, K-220, S-207, S-215 which are polyoxyalkylene alkyl ethers A-10R, A-13P, NC-203, NC-207 (manufactured by NOF Corporation), Emulgen 106, 108, 707, 709, A-90, A-60 (manufactured by Kao Corporation), Floren G-70, D-90 (manufactured by Kyoeisha Chemical Co., Ltd.), Poem J-0081HV (manufactured by Riken Vitamin Co., Ltd.), Adekatol NP-620, NP-650, NP-660, NP-675, NP-683, NP-686, Adeka Coal CS-141E, TS-230E (manufactured by Adeka), etc., Sorgen 30V, 40, TW-20, TW-80, Neugen CX-100 (first Work made by Pharmaceutical Co., Ltd.) and the like.
Moreover, the acetylene glycol surfactant represented by a following formula is mentioned.

（式中、０≦ｐ＋ｑ≦５０、Ｒ^１１、Ｒ^１２、Ｒ^１３、Ｒ^１４はそれぞれ独立にアルキル基、好ましくは炭素数１〜６のアルキル基である。）

(In the formula, 0 ≦ p + q ≦ 50, R ¹¹ , R ¹² , R ¹³ and R ¹⁴ are each independently an alkyl group, preferably an alkyl group having 1 to 6 carbon atoms.)

Specifically, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1- Hexin-3-ol and the like are exemplified, and commercially available products are Surfinol 104, 82, 465, 485, or TG (both available from Air Products and Chemicals. Inc.), Orphin E1004, E1010 (Nisshin Chemical Industry) Etc.).
The surfactant is not limited to the above, and any anionic, cationic, amphoteric or nonionic surfactant may be used, and it may be appropriately selected depending on the purpose of addition.
These surfactants may be added alone or in combination.

(Other additives)
You may add stabilizers, such as antioxidant and a ultraviolet absorber. Examples of the antioxidant include BHA (2,3-butyl-4-oxyanisole), BHT (2,6-di-t-butyl-p-cresol), polyvalent carboxylic acid, epoxidized soybean oil and the like. . Further, as the ultraviolet absorber, a benzophenone compound or a benzotriazole compound can be used.
Furthermore, as other additives, known are surface conditioners, leveling agents (acrylic and silicon-based), antifoaming agents, pH adjusting agents, bactericides, antiseptics, deodorants, charge adjusting agents, wetting agents, and the like. These additives may be added as optional components.

<Content ratio of oil-based ink composition>
The content of the solvent is usually 50 to 95% by mass, preferably 70 to 95% by mass, and more preferably 80 to 90% by mass in the oil-based ink composition.
The content of the color material is usually 0.5 to 25% by mass, preferably 0.5 to 15% by mass, and more preferably 1 to 10% by mass in the oil-based ink composition.
The content of the binder resin in the oil-based ink composition is usually 0.1 to 10.0% by mass, preferably 1.0 to 10.0% by mass, more preferably 3.0 to 8.0% by mass. . When the upper limit of the binder resin content is exceeded, there is a risk that the discharge response will be lowered or the maintainability will be deteriorated. Further, when the content exceeds the lower limit of the content of the binder resin, the drying property is slowed down, and there is a possibility that the printed surface is deteriorated in abrasion resistance and alcohol resistance.
In addition, when a dispersing agent is included as an optional component, it is usually 5 to 200 parts by weight, preferably 30 to 120 parts by weight with respect to 100 parts by weight of the color material, and may be appropriately selected depending on the color material to be dispersed. .
In addition, when various additives are included as optional components, the antioxidant is usually 0.001 to 3.0% by mass in the oil-based ink composition. Moreover, an ultraviolet absorber is 0.01-0.5 mass% normally in an oil-based ink composition. Further, the surfactant is usually 0.5 to 4.0% by mass in the oil-based ink composition.

<Method for preparing oil-based ink composition>
In the method for preparing an oil-based ink composition for ink-jet recording of the present invention, the blending order of each component and the blending method are arbitrary. For example, the properties of the blend at each stage of the manufacturing process and the ease of manufacturing are taken into consideration. Can be determined. For example, each component can be blended independently one by one, or supply and blending of each component can be performed together to obtain a blend of each component at once. Moreover, after mix | blending 2 types or 3 or more types of components previously, it can also mix | blend with the remaining other components. In this case, when two or more components are blended in advance, the amount of the components to be blended in advance may be the total amount of each component or a part of the required amount of each component.

  For example, first, part or all of each solvent used in the mixed solvent is mixed to obtain a solvent in the oil-based ink composition. For example, when a dispersant is used, a color material and a dispersant are added to a part of the solvent, and mixed and dispersed by a ball mill, a bead mill, an ultrasonic wave, a jet mill or the like to prepare a color material dispersion. It is obtained by adding the remainder of the solvent obtained above, a binder resin, and other additives to the obtained colorant dispersion with stirring. For example, when an acrylic resin solution-polymerized using a radical polymerization initiator in a polyoxyalkylene glycol dialkyl ether solvent is used, the solution-polymerized acrylic resin solution can be used as it is.

The obtained oil-based ink composition for ink-jet recording is preferably adjusted to have a viscosity at 20 ° C. of 2 to 15 mPa · s, preferably 3 to 5 mPa · s.
The surface tension in the oil-based ink composition of the present invention is usually 20 to 50 mN / m, preferably 20 to 35 mN / m, from the viewpoints of ink wetting and spreading and ink droplet ejection properties. The surface tension is measured by a surface tension meter (for example, “DY-300” manufactured by Kyowa Interface Science Co., Ltd.).
These physical properties are not limited to the above, and can be arbitrarily adjusted according to the characteristics of the inkjet head.

2. Inkjet recording method The inkjet recording method according to the present invention is an inkjet recording method in which the oil-based ink composition for inkjet recording according to the present invention is ejected by an inkjet method to perform recording on a recording medium.
Since the oil-based ink composition of the present invention has printability suitable for high-speed printing and high drying properties, for example, an ink-jet recording apparatus equipped with a high-speed printing mode is used to eject ink by an ink-jet method, thereby recording media It can be advantageously used in an ink jet recording method for performing recording. Here, the high-speed printing mode is commonly used when creating a banner advertisement to be displayed on a large signboard, for example, and includes a printing method in which large droplets of ink are ejected while the inkjet head is driven in both directions.
In addition, the oil-based ink composition of the present invention has high ejection response and drying property even at high-speed printing, and has excellent fine line image reproducibility, solid image uniformity, and abrasion resistance. Suitable for high-definition printing, for example, using an inkjet recording apparatus having a high-density head as an inkjet head, and advantageously used in an inkjet recording method in which ink is ejected by an inkjet method and recording is performed on a recording medium. it can. The high-density head here has, for example, the number of nozzles of 180 dpi to 360 dpi, which is twice the number of conventional nozzles, and ink dots close to a perfect circle are formed by liquid repellent treatment on the head surface, and the accuracy of the landing position And a head that has a higher discharge speed than conventional heads and can achieve high image quality.

As a recording medium to which the ink jet recording method of the present invention is applied, a recording surface mainly composed of a resin is preferably used. Examples of the resin include a polyvinyl chloride polymer, acrylic, PET, polycarbonate, PE, PP. Etc. are used. In particular, the printing surface is suitable for recording on a recording medium made of a hard or soft polyvinyl chloride polymer. Examples of the recording medium having a printing surface made of a polyvinyl chloride polymer include a polyvinyl chloride substrate (film or sheet).
The oil-based ink composition for ink-jet recording of the present invention enables printing on a non-treated surface of a polyvinyl chloride base material, but has a polyvinyl chloride group having a printing surface surface-treated with an ink receiving resin. It may be a material, PET film or paper.

Hereinafter, the present invention will be specifically described with reference to examples. These descriptions do not limit the present invention.
The mass average molecular weight is “HLC-8220GPC” (column: Shodex LF-404 (Showa Denko)) manufactured by Tosoh Corporation, column temperature, 40 ° C., mobile phase: THF (tetrahydrofuran), mobile phase. Flow rate: 0.35 mL / min, sample concentration 0.2 mass% solution, sample injection amount 10 μL, detector: differential refractometer), measurement was performed by gel permeation chromatography (GPC) using polystyrene as a standard. .
The average particle diameter (D50) means the volume average particle diameter at an integrated value of 50% in the particle size distribution obtained by the laser diffraction / scattering method. In the present invention, the measurement was performed using a particle size analyzer Microtrac UPA150 manufactured by Nikkiso Co., Ltd.
The viscosity was measured using an “AMVn” viscometer manufactured by Anton Paar. The surface tension was measured using “DY-300” manufactured by Kyowa Interface Science Co., Ltd.

(Synthesis Example 1: Synthesis of acrylic resin 1)
In 300 g of diethylene glycol diethyl ether kept at 100 ° C., a mixture of 200 g of methyl methacrylate and 6.3 g of t-butylperoxy-2-ethylhexanoate was added dropwise over 1.5 hours. After completion of dropping, the mixture was reacted at 100 ° C. for 2 hours and then cooled to obtain a colorless and transparent polymer solution of methyl methacrylate (solid content: 39.5%). The obtained polymer (acrylic resin 1) had a Tg of 105 ° C. When GPC measurement was performed, the mass average molecular weight was 18000.

(Synthesis Example 2: Synthesis of acrylic resin 2)
Using a mixture of 200 g of methyl methacrylate and 12.6 g of t-butylperoxy-2-ethylhexanoate, a colorless and transparent polymer solution of methyl methacrylate (solid content) was synthesized by the same synthesis method as for acrylic resin 1. 39.5%). The obtained polymer (acrylic resin 2) had a Tg of 105 ° C. and a mass average molecular weight of 11,000.

(Synthesis Example 3: Synthesis of acrylic resin 3)
Using a mixture of 200 g of methyl methacrylate and 2.0 g of t-butylperoxy-2-ethylhexanoate, a colorless and transparent polymer solution of methyl methacrylate (solid content) by the same synthesis method as acrylic resin 1 39.4%). The obtained polymer (acrylic resin 3) had a Tg of 105 ° C. and a weight average molecular weight of 48,000.

(Synthesis Example 4: Synthesis of acrylic resin 4)
Using a mixture of 180 g of methyl methacrylate, 20 g of n-butyl methacrylate and 3.6 g of t-butylperoxy-2-ethylhexanoate, a colorless and transparent methyl methacrylate was synthesized by the same synthesis method as acrylic resin 1. And a copolymer solution of n-butyl methacrylate (solid content: 39.8%) were obtained. The obtained polymer (acrylic resin 4) had a Tg of 94 ° C. and a mass average molecular weight of 30000.

[Example 1]
A mixed solvent having the following composition was prepared as a solvent.
Amide solvent: Examide M100 (trade name, in the amide solvent represented by the general formula (1), R ¹ is a methyl group, R ² and R ³ are methyl groups, manufactured by Idemitsu Kosan Co., Ltd.) 9 0.5 parts by mass Lactone solvent: γ-butyrolactone 9.5 parts by mass Polyoxyalkylene glycol monoalkyl ether having a boiling point of 200 ° C. to 330 ° C .: Triethylene glycol monobutyl ether (boiling point 271.2 ° C.): 6.0 parts by mass Other solvent: 63.8 parts by mass of diethylene glycol diethyl ether In part of the solvent having the above composition, 4.0 parts by mass of carbon black (MA-8, manufactured by Mitsubishi Chemical Corporation) and a dispersant (polyester polymer compound) , Solsperse 32000, manufactured by Lubrizol Corporation) and 2.0 parts by mass, and stirred with a dissolver at 3,000 rpm for 1 hour After that, it was predispersed in a bead mill filled with zirconia beads (2 mm) and further dispersed in a nanomill filled with zirconia beads (0.3 mm) to obtain a colorant dispersion having an average particle size of 65. It was 0 nm.
While stirring the obtained colorant dispersion at 4,000 rpm, 4.5 parts by mass of the acrylic resin 1 of Synthesis Example 1 and vinyl chloride-vinyl acetate copolymer 1 (trade name: Solvain CLL (Mn 18000) An oil-based ink composition for ink-jet recording of the present invention was prepared by adding 0.5 part by mass of Shin Chemical Co., Ltd.) and the remainder of the mixed solvent prepared above. The viscosity was 4.2 mPa · s (20 ° C.). The surface tension was 28.6 mN / m.

[Examples 2 to 30]
Examples 2 to 30 are the same as Example 1 except that the mixed solvent, binder resin, and coloring material used, and the contents thereof are changed as shown in Table 1-1 and Table 1-2 below. An oil-based ink composition for inkjet recording was prepared. The average particle size of the dispersion of each colorant was 110 nm for cyan, 155 nm for magenta, and 135 nm for yellow. The viscosity and surface tension of each oil-based ink composition for ink jet recording are also shown in Table 1. Moreover, in Table 1-1, Table 1-2, and Table 2, the compounding quantity of binder resin is shown with the amount of solid content.
Abbreviations for solvents, binder resins, dispersants, surfactants, and coloring materials other than those used in Example 1 are as follows.
Examide B100 (trade name, in the amide solvent represented by the general formula (1), R ¹ is an n-butyl group, R ² and R ³ are methyl groups, manufactured by Idemitsu Kosan Co., Ltd.)
・ Vinyl chloride copolymer 2 (a copolymer containing vinyl chloride and vinyl acetate, trade name Solvine CL (Mn 25000), manufactured by Nissin Chemical Industry Co., Ltd.)
Dispersant 2 (Polyester polymer compound, Solsperse 33000, manufactured by Lubrizol)
・ Surfactant 1 (Nonion E-202S, manufactured by NOF Corporation)
・ Surfactant 2 (Sorgen 30V, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.)
Surfactant 3 (Floren D-90, manufactured by Kyoeisha Chemical Co., Ltd.)
Cyan (P.B.15: 4) (Cyanine Blue CP-1, manufactured by Dainichi Seika Kogyo Co., Ltd.)
・ Magenta (PR 122) (FASTGEN SUPER MAGENTA RG, manufactured by DIC Corporation)
・ Yellow (P.Y.155) (INK JET YELLOW 4GC VP 3854, manufactured by Clariant)

[Comparative Examples 1-14]
The oil-based ink composition for ink-jet recording of Comparative Examples 1 to 14 was the same as Example 1 except that the mixed solvent, binder resin, and coloring material used, and the contents thereof were changed as shown in Table 2 below. A product was prepared. Table 2 also shows the viscosity and surface tension of each oil-based ink composition for inkjet recording.

<Evaluation>
In the evaluation criteria, the evaluations AA, A, and B are superior to the conventional ones or have no practical problems, and the evaluation C has no practical advantage or problems compared to the conventional ones. Is.
The evaluation using printing was performed by printing on a polyvinyl chloride film (IMAGin JT5829R: manufactured by MACtac).
(1) Print drying property Using a printer (trade name: VersaArt RE-640, manufactured by Roland DG Co., Ltd.), using the oil-based ink composition for ink-jet recording, printing a solid part in a high-quality printing mode (1440 × 720 dpi). The time until drying at 40 ° C. was measured.
Evaluation AA: Dry in less than 3 minutes.
Evaluation A: Dry in 3 minutes or more and less than 5 minutes.
Evaluation B: Dry in 5 minutes or more and less than 7 minutes.
Evaluation C: Dry at 7 or more.

(2) Solid Image Uniformity Using the above printer, the solid part was printed in bidirectional high-speed printing mode (540 × 360 dpi) using each oil-based ink composition for ink-jet recording, and visually evaluated.
Evaluation A: The solid portion is well filled and there is no variation in density.
Evaluation B: The solid portion is well filled, but there is variation in density in the plane.
Evaluation C: Unevenness is observed in the filling of the solid portion, and white spots and density variations are observed.

(3) Fine line image reproducibility Using the above-mentioned printer, fine line printing was performed in a bidirectional high-speed printing mode (540 × 360 dpi) using each oil-based ink composition for ink-jet recording, and visually evaluated.
Evaluation A: A fine line is reproduced.
Evaluation B: Slight bleeding occurs, but visual design is not impaired.
Evaluation C: The line is thick and the image is not reproduced.

(4) Surface glossiness The above printer was used to print a solid portion in a high-quality printing mode (1440 × 720 dpi) using each oil-based ink composition for inkjet recording, and visually evaluated.
Evaluation A: The surface is glossy Evaluation B: The surface gloss is slightly inferior, but the visual design is not impaired.
Evaluation C: The surface is not glossy and the surface of the original fabric is eroded

(5) Abrasion resistance Using the above-described printer, the solid part was printed in the high-quality print mode using each oil-based ink composition for inkjet recording, and then dried at 40 ° C. for 0.5 hour. Thereafter, an area in which the printed surface was rubbed 100 times with a cotton cloth under a load of 500 g with a Gakushin type friction fastness tester (product name AB-301, manufactured by Tester Sangyo Co., Ltd.) was visually confirmed and evaluated.
Evaluation A: No damage at all.
Evaluation B: Some color fading is observed on the surface of the printed material.
Evaluation C: There is a portion where the ink is peeled off and the substrate can be seen.

(6) Printer member suitability (adhesive for head)
A cured product obtained by drying an epoxy adhesive (two-part curable epoxy adhesive “1500”, manufactured by Cemedine Co., Ltd.) used for an ink jet head member at 60 ° C. for 1 day, 0.2 g of each of the oil-based properties for ink jet recording. It was immersed in the ink composition and allowed to stand at 60 ° C. for 1 week to conduct an immersion test, and the change in the weight of the cured product was measured.
Evaluation A: Weight change rate is less than 2.5%.
Evaluation B: The weight change rate is 2.5% or more and less than 5%.
Evaluation C: The weight change rate is 5% or more.

(7) Printer member suitability (absorber for head cap)
Ink absorber PVA sponge ("Belle eater (A)" manufactured by Fuji Chemical Co., Ltd.) 1cm x 2cm x 1mm used for the head cap member of an inkjet head is immersed in each ink-jet ink composition for 7 days. Then, after drying, deformation and deterioration of the absorber were confirmed.
Evaluation A: The volume change rate is less than 10%, and there is no deterioration of the material.
Evaluation B: The volume change rate is 10% to less than 15%, and there is no deterioration of the material.
Evaluation C: The volume change rate is 15% or more, or the material is deteriorated.

(8) Suitability for high-speed printing Using the above-mentioned printer, fine lines were printed in the bidirectional high-speed printing mode (360 × 360 dpi) using each oil-based ink composition for inkjet recording, and visually confirmed and evaluated.
Evaluation A: The fine line is correctly reproduced.
Evaluation C: The landing position is displaced and bending is observed.

(9) Intermittent ejection property The above-mentioned printer is filled with each ink-based ink composition for ink jet recording, and intermittent printing is performed on the recording medium at room temperature for a long period of time. The number of occurrences was counted and evaluated.
Evaluation A: Occurrence of dot omission, flight bending or ink scattering was less than 10 times within a 24-hour test period.
Evaluation B: Occurrence of missing dots, flying bends, or ink splashes was 10 times or more and less than 20 times within a test period of 24 hours.
Evaluation C: Occurrence of missing dots, flying curves or ink scattering was 20 times or more within a test period of 24 hours.

(10) Maintenance (tube suitability)
As one evaluation of the maintainability, the drying property in the elastomer tube used for the liquid feeding tube was evaluated. Specifically, 3 mL of each oil-based ink composition for ink-jet recording was placed in an EPDM (ethylene propylene diene rubber) tube 11 cm having an outer diameter of 4 mm and an inner diameter of 2 mm, sealed, and left at 40 ° C. for 1 week. The state of the ink composition was evaluated.
Evaluation A: The ink has fluidity and is not solidified in the tube.
Evaluation B: The fluidity of the ink is reduced to be in a gel form.
Evaluation C: The ink is solidified, and the tube is clogged.

(11) Maintenance (cleaning recovery)
As one evaluation of the maintainability, it was evaluated whether the nozzle clogging can be eliminated by the cleaning operation of the printer when nozzle clogging occurs in the head.
Specifically, using a printer (trade name VersaArt RE-640, manufactured by Roland DG Co., Ltd.) equipped with a cleaning system, each oil-based ink composition for inkjet recording was filled and printed at 1.80 m ² after printing. It was left at 25 ° C. for 1 week and then evaluated.
Evaluation A: Nozzle clogging is eliminated with one normal cleaning.
Evaluation B: Nozzle clogging is eliminated by normal cleaning 2 to 3 times.
Evaluation C: Nozzle clogging is not eliminated even after three normal cleanings.
The normal cleaning here is a cleaning method used at the time of start-up or when a dot dropout occurs during the printing process, and the time is short and the ink consumption to be used is relatively small.

(Summary of results)
From Table 1-1 and Table 1-2, the oil-based ink composition for ink-jet recording of the present invention has the print drying property at high speed printing, the image uniformity of the solid portion and the image reproducibility of the fine line, the surface glossiness of the printed matter, It has been clarified that the oil-based ink composition for ink-jet recording is satisfactory in terms of rubbing properties, high-speed printing suitability, intermittent ejection properties, printer member suitability, and maintenance properties.
On the other hand, from Table 2, Comparative Examples 1 to 3 in which the total content of the lactone solvent and the amide solvent was used at a ratio outside the range specified in the present application are excellent in surface gloss and printer member suitability (adhesive for head). It was inferior.
The comparative example 4 which did not use a lactone solvent and an amide solvent was inferior in print drying property, fine line image reproducibility, abrasion resistance, high-speed printing suitability, intermittent discharge property, and maintenance property (tube suitability). Comparative Example 5 in which no polyoxyalkylene glycol monoalkyl ether was used was inferior in solid image uniformity, surface glossiness of printed matter, printer member suitability, and maintainability (tube suitability, cleaning recoverability). In Comparative Examples 6, 7, and 8 in which the glycol monoalkyl ether was used in an amount larger than the specific range, the print drying property, the fine line image reproducibility, the printer member suitability (head cap absorber), and the high-speed print suitability were poor. . Comparative Examples 9, 10, and 13 using a polyoxyalkylene glycol monoalkyl ether having a boiling point less than the lower limit specified in the present application are solid image uniformity, surface glossiness, high-speed printability, intermittent ejection properties, and maintainability. (Tube suitability and cleaning recoverability) were poor. In addition, Comparative Examples 11, 12, and 14 using a boiling point exceeding the upper limit specified in the present application of polyoxyalkylene glycol monoalkyl ether are inferior in print drying property, fine line image reproducibility, and abrasion resistance, and suitable for printer members ( There was a tendency for the head cap absorber) to deteriorate.

Claims (4)

An oil-based ink composition containing a coloring material, a solvent and a binder resin,
The solvent contains at least one of a lactone solvent and an amide solvent, the total amount of the lactone solvent and the amide solvent is 10 to 40% by mass in the total solvent, and the boiling point is 200 ° C. An oil-based ink composition for inkjet recording, comprising 3 to 20% by mass of polyoxyalkylene glycol monoalkyl ether at ˜330 ° C. in all solvents.   The total amount of the lactone solvent and the amide solvent is more than 2.0 parts by weight and less than 6.0 parts by weight with respect to 1 part by weight of the polyoxyalkylene glycol monoalkyl ether solvent. The oil-based ink composition for ink-jet recording according to claim 1, wherein:   The oil-based ink composition for ink jet recording according to claim 1, wherein the binder resin contains an acrylic resin.   The inkjet recording method which discharges the oil-based ink composition for inkjet recording of any one of the said Claims 1-3 with an inkjet method, and records on a recording medium.