JP2018048293A - Oily inkjet ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oily inkjet ink that is excellent in repellency to a nozzle plate and prevents the deterioration of the nozzle plate while at the same time it reduces strike-through of images and gives a high image density.SOLUTION: The oily inkjet ink includes an encapsulated pigment including a pigment and an urethane compound covering the surface of the pigment and a nonaqueous solvent. The urethane compound has an urethane skeleton and a side chain and is a compound insoluble in a nonaqueous solvent. The side chain of the urethane compound includes one or more kinds selected from among an aromatic ring, a heterocyclic ring, a carboxyl group, an amide bond, a fluoroalkyl group having one or more fluorine atoms and a nitrile group.SELECTED DRAWING: None

Description

  The present invention relates to an oil-based inkjet ink.

  The ink jet recording method is a method in which ink jet ink having high fluidity is ejected as droplets from fine nozzles, and an image is recorded on a recording medium placed facing the nozzles, and high speed printing can be performed with low noise. Therefore, it has been spreading rapidly in recent years.

As an oil-based inkjet ink having a low viscosity even at a high pigment concentration, there is a technique using a capsule pigment surface-treated with a (meth) acrylic acid copolymer having an acid value of 30 to 60 (see Patent Document 1).
However, such ink has good wettability with respect to the nozzle plate surface of the head of the inkjet printing apparatus, and tends to adhere to the nozzle plate surface. For this reason, there is a problem that the ink attached to the surface of the nozzle plate hangs on the paper and stains the image, or the ink attached to the surface of the nozzle plate hinders ink ejection.

In addition, an ink jet printing apparatus using oil-based ink is designed so that a head cleaning operation is periodically performed. This head cleaning operation is generally composed of a pressure purge for discharging ink from nozzles and wiping of a nozzle plate.
When ink that adheres easily to the nozzle plate surface is used, if the nozzle plate is wiped, the pigment in the ink becomes an abrasive, scraping off the fluororesin film on the nozzle plate surface, and reducing the ink repellency of the nozzle plate. I might let you.

  To solve the above problem, Patent Document 2 uses a capsule-type pigment in which a compound having an α value of 5 to 60 is added as a side chain and surface-treated with a comb-shaped polyurethane compound miscible with a solvent in an oil-based inkjet ink. Thus, it is disclosed that the nozzle plate is excellent in repellency and can suppress deterioration of the nozzle plate.

JP 2007-314651 A JP 2011-57812 A

On the other hand, in the case of oil-based inkjet ink, when ink is ejected onto the paper, the solvent in the ink penetrates into the paper on the paper surface. At this time, when the pigment penetrates into the paper together with the solvent in the ink, a so-called show-through phenomenon occurs in which the image is shown through on the back side of the paper. When back-through occurs, the image density on the paper surface also decreases.
In Patent Document 2, since a comb-type polyurethane compound that is miscible with a solvent is used as a capsule-type pigment, the capsule-type pigment penetrates into the inside of the paper together with the solvent in the ink, causing back-through and lowering the image density. Sometimes.

  An object of the present invention is to provide an oil-based inkjet ink that is excellent in repellency to a nozzle plate, prevents deterioration of the nozzle plate, reduces image back-through, and obtains a high image density.

The gist of the present invention is as follows.
(1) An encapsulated pigment containing a pigment and a urethane compound that covers the surface of the pigment, and a non-aqueous solvent, the urethane compound having a urethane skeleton and a side chain, and insoluble in the non-aqueous solvent And the side chain of the urethane compound includes one or more selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group. , Oil-based inkjet ink.
(2) The side chain of the urethane compound is one or more selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group. The oil-based inkjet ink according to (1),
(3) The urethane compound has a structure in which units derived from a polyvalent isocyanate and units derived from an alkanolamine are alternately arranged, and the side chain of the urethane compound includes a nitrogen atom of the unit derived from the alkanolamine. The oil-based inkjet ink according to (1) or (2), which binds to the urethane compound via

（式（１）において、
ｍ、ｎ及びｐは、それぞれ独立的に正の整数であり、
Ｙは、任意の２価の基であり、
Ｒは、−Ａ−Ｒ^１であり、Ａは単結合または任意の２価の基であり、Ｒ^１は芳香環含有基、複素環含有基、水素原子、カルボキシ基、アミド結合含有基、１個以上のフッ素原子を有するフルオロアルキル基、及びニトリル基のうちから選択され、これらは置換基を有してもよい。） (4) The oil-based inkjet ink according to (3), wherein the urethane compound further includes a unit derived from asymmetric glycol.
(5) The unit derived from the alkanolamine is:
A unit derived from dialkanolamine to which an acrylate having an aromatic ring is added by Michael,
Units derived from dialkanolamines with Michael addition of heterocyclic acrylamides,
(3) or (1) comprising one or more selected from the group consisting of a dialkanolamine-derived unit to which N-alkylamide is Michael-added, and a unit from N-N-dialkylamide to which dialkanolamine is added to Michael The oil-based inkjet ink as described in 4).
(6) The oil-based inkjet ink according to any one of (1) to (5), wherein the urethane compound has a repeating unit represented by the following formula (1).

(In Formula (1),
m, n and p are each independently a positive integer;
Y is an arbitrary divalent group,
R is -A-R ¹ , A is a single bond or any divalent group, R ¹ is an aromatic ring-containing group, a heterocyclic ring-containing group, a hydrogen atom, a carboxy group, an amide bond-containing group, 1 It is selected from a fluoroalkyl group having one or more fluorine atoms and a nitrile group, and these may have a substituent. )

(7) The side chain of the urethane compound has at least one selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group; The oil-based inkjet ink according to any one of (1) to (6), comprising an alkoxysilyl group.
(8) The oil-based inkjet ink according to (7), wherein the urethane compound includes a plurality of alkoxysilyl groups, and at least a part of the plurality of alkoxysilyl groups forms a siloxane bond.

(9) The urethane compound has a structure in which units derived from a polyvalent isocyanate and units derived from a polyhydric alcohol are alternately arranged, the unit derived from the polyhydric alcohol includes a unit derived from an alkanolamine, The unit derived from the alkanolamine is a compound having at least one selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group. The oil-based inkjet ink according to (7) or (8), comprising an added alkanolamine-derived unit A and an alkanolamine-derived unit B having an alkoxysilyl group.
(10) The alkanolamine-derived unit B having an alkoxysilyl group includes a alkanolamine-derived unit to which a compound having an alkoxysilyl group and an unsaturated double bond is added, and an alkoxy group and an epoxy group-containing group. The oil-based inkjet ink according to (9), comprising one or more selected from the group consisting of units derived from alkanolamines into which an alkoxysilyl group has been introduced by a reaction with a compound having:

(11) The urethane compound has a structure in which units derived from a polyvalent isocyanate and units derived from a polyhydric alcohol are alternately arranged, the unit derived from the polyhydric alcohol includes a unit derived from an alkanolamine, The unit derived from the alkanolamine is a compound having at least one selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group. The oil-based ink-jet ink according to (7) or (8), comprising an added alkanolamine-derived unit A, wherein an alkoxysilyl group is introduced into the isocyanate group of the urethane compound via a mercapto group.
(12) The urethane compound has a structure in which units derived from a polyvalent isocyanate and units derived from a polyhydric alcohol are alternately arranged, and the unit derived from the polyhydric alcohol includes a unit derived from an alkanolamine, The unit derived from the alkanolamine is a compound having at least one selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group. The oil-based ink-jet ink according to (7) or (8), comprising an added alkanolamine-derived unit A, wherein an alkoxysilyl group is introduced into the hydroxy group of the urethane compound via an isocyanate group.

  According to the present invention, it is possible to provide an oil-based inkjet ink that has excellent repellency to a nozzle plate, prevents deterioration of the nozzle plate, reduces image back-through, and obtains a high image density.

Hereinafter, the present invention will be described using an embodiment. The illustration in the following embodiment does not limit the present invention.
(First embodiment)
The oil-based inkjet ink according to the present embodiment (hereinafter sometimes simply referred to as ink) includes an encapsulated pigment containing a pigment and a urethane compound that coats the surface of the pigment, and a non-aqueous solvent. A compound having a urethane skeleton and a side chain and insoluble in a non-aqueous solvent, wherein the side chain of the urethane compound is an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, And one or more selected from nitrile groups.
According to this embodiment, it is excellent in the repellency with respect to a nozzle plate, can prevent deterioration of a nozzle plate, can reduce the image see-through of a printed matter, and can raise an image density.

In the present embodiment, the side chain of the urethane compound has the above-described structure, so that ink repellency and wipe durability with respect to the nozzle plate can be improved. Further, after specifying the side chain of the urethane compound, the urethane compound has low solubility in the ink solvent, so that image see-through can be reduced and the image density can be increased.
When the urethane compound becomes less soluble in the ink solvent, the pigment encapsulated with the urethane compound has higher solvent detachability on the recording medium. Then, when the pigment is detached from the solvent on the surface of the recording medium and the solvent penetrates into the recording medium, the pigment tends to remain on the surface of the recording medium. As a result, image see-through can be reduced and the image density can be increased.

Moreover, since the urethane compound is excellent in the adsorptivity to the pigment, the coating efficiency of the pigment can be improved. Then, in the ink, it is possible to prevent the ink solvent from being absorbed by the urethane compound of the film and penetrating into the pigment. As a result, the releasability between the pigment and the solvent can be improved.
In addition, the pigment covering efficiency is improved by the urethane compound, so that the surface of the pigment is prevented from directly contacting the nozzle plate and being polished, and the wipe durability can be further improved.

The ink of this embodiment includes an encapsulated pigment, and the encapsulated pigment includes a pigment and a urethane compound that covers the surface of the pigment.
As the pigment, organic pigments such as azo pigments, phthalocyanine pigments, polycyclic pigments, dyed lake pigments, and inorganic pigments such as carbon black and metal oxides can be used. Examples of the azo pigment include a soluble azo lake pigment, an insoluble azo pigment, and a condensed azo pigment. Examples of phthalocyanine pigments include metal phthalocyanine pigments and metal-free phthalocyanine pigments. Polycyclic pigments include quinacridone pigments, perylene pigments, perinone pigments, isoindoline pigments, isoindolinone pigments, dioxazine pigments, thioindigo pigments, anthraquinone pigments, quinophthalone pigments, metal complex pigments. And diketopyrrolopyrrole (DPP). Examples of carbon black include furnace carbon black, lamp black, acetylene black, and channel black. Examples of the metal oxide include titanium oxide and zinc oxide. These pigments may be used alone or in combination of two or more.

The average particle diameter of the pigment is preferably 300 nm or less, more preferably 200 nm or less, from the viewpoint of ejection stability and storage stability.
The pigment is usually 0.01 to 20% by mass with respect to the total amount of the ink, and preferably 1 to 15% by mass from the viewpoint of printing density and ink viscosity.

In encapsulated pigments, part or all of the surface of the pigment is covered with a urethane compound.
The urethane compound is preferably insoluble in the non-aqueous solvent used in the ink.
Specifically, the urethane compound is preferably dissolved at 23 g and 5 g or less, more preferably 3 g or less, and even more preferably 1 g or less with respect to 100 g of the non-aqueous solvent used in the ink. . More preferably, the urethane compound does not substantially dissolve at 23 ° C. in the non-aqueous solvent used in the ink.
The solubility in the non-aqueous solvent used in the ink is the solubility in a mixture in which two or more solvents are mixed in the same mixing ratio as the ink when two or more solvents are blended in the ink.

A urethane compound has a side chain with a urethane skeleton. This side chain preferably contains one or more selected from an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group.
The urethane compound has a comb-shaped polyurethane structure because the side chain branches from the urethane skeleton.

  As the urethane compound, for example, a compound including a main chain composed of a urethane skeleton and a side chain graft-polymerized to the main chain can be used. Here, what was obtained by making polyhydric isocyanate and polyhydric alcohol react can be used for urethane frame | skeleton.

The urethane compound has, for example, a structure in which units derived from polyisocyanate and units derived from alkanolamine are alternately arranged, and the side chain of the urethane compound is bonded via a nitrogen atom of the unit derived from alkanolamine. Can be used.
Such a urethane compound can be obtained by reacting a polyvalent isocyanate with an alkanolamine or a derivative thereof.

As the alkanolamine, monoalkanolamine, dialkanolamine, or a combination thereof can be used.
Examples of the monoalkanolamine include monomethanolamine, monoethanolamine, mono (n-propanol) amine, monoisopropanolamine, monobutanolamine, monopentanolamine, monohexanolamine, monoheptanolamine, monooctanolamine, Monononanolamine, monodecanolamine, monoundecanolamine, monododecanolamine, monotridecanolamine, monotetradecanolamine, monopentadecanolamine, monohexadecanolamine, and the like can be used.
As the dialkanolamine, for example, dimethanolamine, diethanolamine, di (n-propanol) amine, diisopropanolamine, dibutanolamine, dipentanolamine, dihexanolamine, diheptanolamine and the like can be used.
The monoalkanolamine and dialkanolamine may each have a branched chain or may have a substituent.

Preferably, dialkanolamine can be used in the urethane compound.
A urethane bond “—NH—CO—O—” is formed by the isocyanate group of the polyvalent isocyanate and the hydroxy group of the dialkanolamine which is a dihydric alcohol, and “— (CH ₂ ) _m derived from dialkanolamine”. A bond represented by “—NR— (CH ₂ ) _n —” is formed. Here, m and n are positive integers, and R is a side chain.

Specifically, a urethane compound having a repeating unit represented by the following formula (1) can be used. In the formula (1), R is a side chain, and the unit “—O— (CH ₂ ) _m —NR— (CH ₂ ) _n —O—” derived from a dialkanolamine having the side chain R and a divalent isocyanate is derived. The units “—CONH—Y—NHCO—” are alternately arranged.

In Formula (1), m and n are each independently a positive integer, and preferably an integer of 1 to 18. p is a positive integer, varies depending on the polymerization degree of the urethane compound, and may be an integer of 5 to 100.
Y is an arbitrary divalent group.
R is -A-R ¹ , A is a single bond or any divalent group, R ¹ is an aromatic ring-containing group, a heterocyclic ring-containing group, a hydrogen atom, a carboxy group, an amide bond-containing group, 1 It is selected from a fluoroalkyl group having one or more fluorine atoms and a nitrile group, and these may have a substituent.

In the formula (1), R is —A—R ¹ , and A preferably includes — (CH ₂ ) ₂ —. In this case, the dialkanolamine “OH— (CH ₂ ) _m —NH— (CH ₂ ) _n —OH” is subjected to a Michael addition reaction of a vinyl monomer having a group represented by R ¹ to give a dialkanolamine nitrogen. A target urethane compound can be produced using a dialkanolamine derivative in which a group represented by R ¹ is introduced with an atom “N” as a base point.
The general formula of dialkanolamine derivatives is shown below.
OH— (CH ₂ ) _m —NR— (CH ₂ ) _n —OH
Here, m and n are each independently a positive integer, preferably an integer of 1 to 18. R is a side chain.

Further, instead of or together with dialkanolamine or a derivative thereof, monoalkanolamine or a derivative thereof may be used.
The monoalkanolamine derivative can be produced, for example, by subjecting a monoalkanolamine to a Michael addition reaction with a vinyl monomer having a group represented by R ¹ in the same manner as the dialkanolamine described above.

The introduction of the side chain by this Michael addition reaction is usually performed on the dialkanolamine monomer before the urethanization reaction, but is performed on the dialkanolamine-derived unit contained in the urethane compound after polymerization. Also good.
As the vinyl monomer, a monomer having an acryloyloxy group such as acrylate, a monomer having an acryloyl group, acrylamide, a monomer having a vinyl group, or the like can be used.
For example, when the acrylate having a group represented by R ¹ and dialkanolamine are subjected to a Michael addition reaction, the reaction proceeds according to the following formula, and a dialkanolamine derivative can be obtained.

(1) Side chain derived from acrylate As an example of the urethane compound, in the formula (1),
The side chain R is — (CH ₂ ) ₂ —COO—R ^1a
R ^1a is a hydrogen atom, an aromatic ring-containing group, a heterocyclic ring-containing group, or a fluoroalkyl group having one or more fluorine atoms, and these may have a substituent.
According to such a urethane compound, it is possible to improve image see-through and image density as well as ink repellency and wipe durability with respect to the nozzle plate.
When the side chain of the urethane compound has a carboxy group, an aromatic ring, or a heterocyclic ring, the ink storage stability can be further favorably maintained.
Further, since the side chain of the urethane compound has a fluoroalkyl group having one or more fluorine atoms, the scratch resistance of the printed matter and the fixing property to the recording medium can be further improved.

When R ^1a is a hydrogen atom, a carboxy group is introduced into the side chain of the urethane compound.
Examples of the aromatic ring-containing group in R ^1a include the following functional groups.

Examples of the heterocyclic group-containing group in R ^1a include the following functional groups.

As the fluoroalkyl group having one or more fluorine atoms in R ^1a , 50% or more, preferably 80% or more, of hydrogen atoms (numbers) of linear or branched alkyl groups having 1 to 10 carbon atoms are fluorine. Those substituted with atoms are preferred. Examples of the fluoroalkyl group include the following functional groups.

When the above urethane compound is produced, a dialkanolamine “OH— (CH ₂ ) _m —NH— (CH ₂ ) _n —OH” based on the nitrogen atom “N” is used as a base and the following monomers are introduced. Alkanolamine derivatives can be used. An acrylate having an aromatic ring is preferable.

Moreover, as an example of a urethane compound, in Formula (1),
The side chain R is — (CH ₂ ) ₂ —COO—R ^1a
R ^1a is a nitrogen atom-containing group, and these may have a substituent.
When the above urethane compound is produced, the dimethylaminomethyl acrylate, dimethylamino is derived from the nitrogen atom “N” of dialkanolamine “OH— (CH ₂ ) _m —NH— (CH ₂ ) _n —OH”. A dialkanolamine derivative into which ethyl acrylate, diethylaminoethyl acrylate or the like is introduced can be used.

(2) Side chain derived from acrylamide As an example of the urethane compound, in formula (1),
The side chain R is — (CH ₂ ) ₂ —R ^1b ,
R ^1b is an amide bond-containing group represented by the following formula (2).
―CO-NR'R ''
In the formula (2), R ′ and R ″ are each independently a hydrogen atom, an alkyl group, or a group that forms a heterocyclic ring with N, R ′, and R ″, and these have a substituent. May be.
According to such a urethane compound, it is possible to improve image see-through and image density as well as ink repellency and wipe durability with respect to the nozzle plate.
When the side chain of the urethane compound has an amide bond-containing group, the storage stability of the ink can be further favorably maintained.

When both R ′ and R ″ are hydrogen atoms, an amide group is introduced into the side chain of the urethane compound.
When either one of R ′ and R ″ is an alkyl group and the other is a hydrogen atom, a monoalkylamide group is introduced into the side chain of the urethane compound.
When both R ′ and R ″ are alkyl groups, a dialkylamide group will be introduced into the side chain of the urethane compound.
The alkyl groups of the monoalkylamide group and the dialkylamide group may each independently have a substituent such as an amino group or a hydroxy group.
Since the side chain of the urethane compound has a monoalkylamide group or a dialkylamide group, the wipe durability can be further improved.
R ′ and R ″ may form a heterocyclic ring with the nitrogen atom “N” of “—CO—NR′R ″”.

  Examples of “—NR′R ″” include the following functional groups.

  When the above urethane compound is produced, a dialkanolamine derivative in which the following monomers are introduced based on the nitrogen atom of dialkanolamine can be used. N-acrylamide, N, N-diacrylamide, and acrylamide having a heterocyclic ring are preferable.

(3) Acrylonitrile-derived side chain As an example of the urethane compound, in the formula (1),
The side chain R is — (CH ₂ ) ₂ —R ^1c , and R ^1c is a nitrile group.
In producing such a urethane compound, a dialkanolamine derivative in which the following acrylonitrile is introduced based on the nitrogen atom of dialkanolamine can be used.

According to such a urethane compound, it is possible to improve image see-through and image density as well as ink repellency and wipe durability with respect to the nozzle plate.
Since the side chain of the urethane compound has a nitrile group, the wipe durability can be further improved, and the storage stability of the ink can be maintained well.

The urethane compound may include one or more of the above-mentioned side chain structures. A urethane compound having two or more side chains can be obtained by reacting a polyvalent isocyanate compound with two or more dialkanolamine derivatives having different functional groups.
Preferably, the urethane compound has a first side chain having an aromatic ring and a second side chain having a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, or a nitrile group. It is preferable to have. While the urethane compound has the second side chain, the respective effects are exhibited, and the first side chain has an aromatic ring, so that the wettability with respect to the nozzle plate can be reliably improved. The first side chain and the second side chain are preferably in a molar ratio of 25:75 to 75:25.

In the urethane compound, as the unit derived from the polyvalent isocyanate, in the above formula (1), Y preferably has the following structure.
A linear or branched alkylene group having 1 to 8 carbon atoms;
A divalent group having an aromatic ring such as benzene or naphthalene;
A divalent group having a cycloalkane such as cyclohexane or norbornene;
Etc.

  The polyvalent isocyanate used when producing such a urethane compound is a compound having two or more isocyanate groups, and may be any of aliphatic polyisocyanate, alicyclic polyisocyanate, aromatic polyisocyanate and the like. Good.

Specific examples of the polyvalent isocyanate include 1,6-diisocyanate hexane, 1,3-bis (isocyanatomethyl) benzene, 1,3-bis (isocyanatomethyl) cyclohexane, 1,5-naphthalene diisocyanate, and diphenylmethane. Diisocyanates such as -4,4-diisocyanate, hexamethylene diisocyanate, metaxylene diisocyanate;
Triisocyanates such as 1-methylbenzene-2,4,6-triyltriisocyanate, 1,6,11-triisocyanatoundecane;
And polyisocyanates such as polymethylene polyphenyl polyisocyanate.
Examples of the polyvalent isocyanate compound having three or more isocyanate groups include, for example, a polyvalent isocyanate compound containing an isocyanurate ring, a polyvalent isocyanate compound containing an adduct structure, a polyvalent isocyanate compound containing a burette structure, and undodione. A polyvalent isocyanate compound containing a structure can be used.
Examples of the polyvalent isocyanate compound containing an isocyanurate ring include hexamethylene diisocyanate isocyanurate and 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate isocyanurate. Examples of the polyvalent isocyanate compound containing an adduct structure include hexamethylene diisocyanate containing an adduct structure.
Particularly preferably, divalent isocyanate can be used.

The urethane compound may further contain units derived from other polyhydric alcohols other than alkanolamine, in addition to units derived from polyvalent isocyanate and units derived from alkanolamine. By using a polyhydric alcohol having no side chain as the other polyhydric alcohol, the urethane compound can be prevented from crystallizing in the ink solvent, and miscibility with the ink solvent can be obtained.
Examples of other polyhydric alcohols include ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3 propanediol, polyethylene glycol, and polypropylene glycol. The unit derived from this may be contained in a urethane compound by 1 type or in combination of 2 or more types.
Especially, it is preferable that a urethane compound contains the unit derived from asymmetric glycol. The asymmetric glycol is preferably propylene glycol or polypropylene glycol having 3 to 600 carbon atoms.

  The urethane compound preferably contains a unit derived from an alkanolamine and a unit derived from another polyhydric alcohol in a molar ratio of 25:75 to 75:25 (alkanolamine: other dihydric alcohol).

The urethane compound represented by the formula (1) reacts a polyhydric alcohol containing diethanolamine and optionally other polyhydric alcohol with a polyvalent isocyanate in a low-boiling aprotic solvent such as methyl ethyl ketone. Can be manufactured.
It is preferable to mix and react the polyhydric alcohol and the polyvalent isocyanate so that the isocyanate group of the polyvalent isocyanate is 0.60 to 1.02 mol with respect to 1.0 mol of the hydroxy group of the polyhydric alcohol. .

  The weight average molecular weight (Mw, GPC method, standard polystyrene conversion) of the urethane compound is preferably 2000 to 40000. When the weight average molecular weight is lower than 2000, the urethane compound may float in the ink solvent and the form of the encapsulated pigment may not be maintained. When the weight average molecular weight of the urethane compound is higher than 40,000, coarse capsule particles are generated, which may cause a decrease in stability and a deterioration in dischargeability. More preferably, the weight average molecular weight of a urethane compound is 2000-30000, More preferably, it is 4000-20000.

  The urethane compound is preferably 0.01 to 30% by mass, more preferably 1 to 20% by mass, based on the total amount of ink.

The oil-based ink may contain a pigment dispersant in order to stabilize the dispersibility of the encapsulated pigment.
Examples of the pigment dispersant include a hydroxyl group-containing carboxylic acid ester, a salt of a long chain polyaminoamide and a high molecular weight acid ester, a salt of a high molecular weight polycarboxylic acid, a salt of a long chain polyaminoamide and a polar acid ester, and a high molecular weight unsaturated acid. Ester, polymer copolymer, modified polyurethane, modified polyacrylate, polyether ester type anionic activator, naphthalene sulfonic acid formalin condensate salt, polyoxyethylene alkyl phosphate ester, polyoxyethylene nonyl phenyl ether, polyester polyamine, Stearylamine acetate, polyethyleneimine compounds and the like are preferably used, and among them, a polymer dispersant is preferably used.

Examples of commercially available pigment dispersants include “Solsperse 5000 (phthalocyanine ammonium salt type), 13940 (polyesteramine type), 17000, 18000 (fatty acid amine type), 11200, 22000, 24000, 28000, 7100, manufactured by Nippon Lubrizol Corporation. (All trade names), “Efka CHEMICALS” “Efka 400, 401, 402, 403, 450, 451, 453 (modified polyacrylate), 46, 47, 48, 49, 4010, 4055 (modified polyurethane)” (any Product name), “Demol P, EP, Poise 520, 521, 530, Homogenol L-18 (polycarboxylic acid type polymer surfactant)” (all trade names) manufactured by Kao Corporation, “Disparon” manufactured by Enomoto Kasei Co., Ltd. KS-860, KS-873N4 (Amine salt of polyester) "(all trade names)," Dacol 202, 206, OA-202, OA-600 (multi-chain polymer non-ionic) "manufactured by Daiichi Kogyo Seiyaku (all trade names) , “DISPERBYK2155, 9077” manufactured by Big Chemie Japan, “Hypermer KD2, KD3, KD11, KD12” manufactured by Croda Japan Co., Ltd., and the like.
The content of the dispersant is sufficient as long as the pigment can be sufficiently dispersed in the ink, and can be appropriately set. For example, the pigment dispersant can be blended with the pigment 1 at a mass ratio of 0.1 to 5.

  As the pigment dispersant, a comb-type polyamide dispersant having a plurality of side chains composed of polyester chains can be preferably used. Comb-structured polyamide dispersants are available as commercial products such as Solsperse 11200 and Solsperse 28000 (both trade names) manufactured by Nippon Lubrizol.

  As the non-aqueous solvent, any of a non-polar organic solvent and a polar organic solvent can be used. These may be used alone or in combination. In the present embodiment, it is preferable to use a water-insoluble organic solvent that does not uniformly mix with the same volume of water at 1 atm and 20 ° C. as the non-aqueous solvent.

Preferable examples of the nonpolar organic solvent include petroleum hydrocarbon solvents such as aliphatic hydrocarbon solvents, alicyclic hydrocarbon solvents, and aromatic hydrocarbon solvents.
Examples of the aliphatic hydrocarbon solvent and the alicyclic hydrocarbon solvent include non-aqueous solvents such as paraffinic, isoparaffinic, and naphthenic solvents, and commercially available products include 0 Solvent L, 0 Solvent M, 0 Solvent H, Cactus normal paraffin N-10, Cactus normal paraffin N-11, Cactus normal paraffin N-12, Cactus normal paraffin N-13, Cactus normal paraffin N-14, Cactus normal paraffin N-15H, Cactus normal paraffin YHNP Cactus normal paraffin SHNP, Isosol 300, Isosol 400, Teclean N-16, Teclean N-20, Teclean N-22, AF Solvent No. 4, AF Solvent No. 5, AF Solvent No. 6, AF Solvent No. 7, Futezol 160, Naphthezol 200, Naphthezol 220 (all manufactured by JX Nippon Oil & Energy Corporation); Isopar G, Isopar H, Isopar L, Isopar M, Exol D40, Exol D60, Exol D80, Exol D95, Exol D110, Exol D130 (Both manufactured by TonenGeneral Sekiyu KK) and the like can be preferably mentioned.
As the aromatic hydrocarbon solvent, grade alkene L, grade alkene 200P (all manufactured by JX Nippon Oil & Energy Corporation), Solvesso 100, Solvesso 150, Solvesso 200, Solvesso 200ND (all manufactured by TonenGeneral Sekiyu KK), etc. Can be preferably mentioned.
The distillation initial boiling point of the petroleum hydrocarbon solvent is preferably 100 ° C. or higher, more preferably 150 ° C. or higher, and even more preferably 200 ° C. or higher. The distillation initial boiling point can be measured in accordance with JIS K0066 “Method for Distillation Test of Chemical Products”.

Preferred examples of the polar organic solvent include fatty acid ester solvents, higher alcohol solvents, higher fatty acid solvents and the like.
For example, isononyl isononanoate, isodecyl isononanoate, methyl laurate, isopropyl laurate, hexyl laurate, isopropyl myristate, isopropyl palmitate, hexyl palmitate, isooctyl palmitate, isostearyl palmitate, methyl oleate, ethyl oleate , Isopropyl oleate, butyl oleate, hexyl oleate, methyl linoleate, ethyl linoleate, isobutyl linoleate, butyl stearate, hexyl stearate, isooctyl stearate, isopropyl isostearate, 2-octyldecyl pivalate, soybean oil Methyl, soybean oil isobutyl, tall oil methyl, tall oil isobutyl, etc., the number of carbon atoms in one molecule is 13 or more, preferably 16-30 fatty acid esters Agent;
A higher alcohol solvent having 6 or more, preferably 12 to 20 carbon atoms in one molecule, such as isomyristyl alcohol, isopalmityl alcohol, isostearyl alcohol, oleyl alcohol, isoeicosyl alcohol, decyltetradecanol;
Higher fatty acid solvents such as lauric acid, isomyristic acid, palmitic acid, isopalmitic acid, α-linolenic acid, linoleic acid, oleic acid, isostearic acid and the like having 12 or more carbon atoms, preferably 14-20 carbon atoms Is mentioned.
The boiling point of polar organic solvents such as fatty acid ester solvents, higher alcohol solvents and higher fatty acid solvents is preferably 150 ° C. or higher, more preferably 200 ° C. or higher, and further preferably 250 ° C. or higher. preferable. The non-aqueous solvent having a boiling point of 250 ° C. or higher includes non-aqueous solvents that do not exhibit a boiling point.

In the method for producing an encapsulated pigment according to this embodiment, it is preferable to use a urethane compound solution obtained by dissolving the above urethane compound in a low-boiling aprotic solvent.
Examples of low-boiling aprotic solvents include amide solvents such as dimethylformamide, diethylformamide, dimethylacetamide, and N-methylpyrrolidone; sulfoxide solvents such as dimethyl sulfoxide; ketone solvents such as methyl ethyl ketone, cyclohexanone, and methyl isobutyl ketone; Examples include ether solvents such as tetrahydrofuran and dioxane; ester solvents such as methyl acetate, ethyl acetate, and butyl acetate; and aromatic hydrocarbon solvents such as toluene and xylene.

This urethane compound solution may be obtained by reacting the above polyisocyanate and an alkanolamine derivative in a low-boiling aprotic solvent, if necessary, with a diluting solvent added.
The encapsulated pigment is prepared by mixing a urethane compound solution with optional components such as a high-boiling solvent for ink, a pigment, and a pigment dispersant, and dispersing the mixture with a disperser such as a bead mill. It can be produced by removing the solvent. For removal of the low boiling point solvent, pressurization, heating, distillation or the like can be used. If desired, it may be prepared through a filter such as a membrane filter.
The obtained encapsulated pigment dispersion can be used as it is as an oil-based ink by adding a diluting solvent if necessary.

In the oil-based ink, the encapsulated pigment is preferably 1 to 40% by mass, more preferably 5 to 30% by mass with respect to the total amount of the ink.
In the oil-based ink, the compounding amount of the urethane compound is preferably 0.1 to 5 with respect to the pigment 1 in terms of mass ratio.
The oil-based ink preferably has a nonvolatile content of 1 to 40% by mass. The blending amount of the ink solvent may be adjusted so that the non-volatile content is obtained.
In the encapsulated pigment manufacturing process, it is preferable that the low-boiling aprotic solvent is blended in a sufficient amount so that aggregation does not occur when the urethane compound is mixed with the ink solvent. The blending amount of the preferred low-boiling aprotic solvent is 1 to 15 with respect to the urethane compound 1 in terms of mass ratio.

  In addition to the above components, the oil-based ink may contain various additives as long as the effects of the present invention are not impaired. As additives, nozzle clogging inhibitors, antioxidants, conductivity modifiers, viscosity modifiers, surface tension modifiers, oxygen absorbers, and the like can be appropriately added. Further, from the viewpoint of color developability, a dye may be used in combination with the encapsulated pigment. These types are not particularly limited, and those used in the field can be used.

  The viscosity of the oil-based inkjet ink varies depending on the nozzle diameter of the ejection head of the inkjet recording system, the ejection environment, and the like, but in general, it is preferably 5 to 30 mPa · s at 23 ° C., preferably 5 to 15 mPa · s. It is more preferable that it is about 10 mPa · s. Here, the viscosity represents a value at 10 Pa when the shear stress is increased from 0 Pa at a rate of 0.1 Pa / s at 23 ° C.

  The printing method using the inkjet ink is not particularly limited, and any method such as a piezo method, an electrostatic method, or a thermal method may be used. When an ink jet recording apparatus is used, it is preferable that the ink according to the present embodiment is ejected from the ink jet head based on a digital signal, and the ejected ink droplets are attached to the recording medium.

  In the present embodiment, the recording medium is not particularly limited, and printing paper such as plain paper, coated paper, special paper, cloth, inorganic sheet, film, OHP sheet, etc., and these are used as a base material and an adhesive layer on the back surface An adhesive sheet or the like provided with can be used. Among these, printing paper such as plain paper and coated paper can be preferably used from the viewpoint of ink permeability.

  Here, the plain paper is paper in which an ink receiving layer, a film layer, and the like are not formed on normal paper. Examples of plain paper include high quality paper, medium quality paper, PPC paper, reprinted paper, recycled paper, and the like. Plain paper is a paper in which ink easily penetrates because paper fibers having a thickness of several μm to several tens of μm form voids of several tens to several hundreds of μm.

  Further, as the coated paper, inkjet coated paper or so-called coated printing paper can be preferably used. Here, the coated printing paper is a printing paper conventionally used in letterpress printing, offset printing, gravure printing, etc., and has an inorganic pigment such as clay or calcium carbonate on the surface of high-quality paper or medium-quality paper. A printing paper provided with a coating layer by a paint containing a binder such as starch. Coated printing paper can be applied to fine coated paper, high-quality lightweight coated paper, medium-weight lightweight coated paper, high-quality coated paper, medium-quality coated paper, art paper, cast coated paper, etc., depending on the coating amount and coating method. being classified.

(Second Embodiment)
Hereinafter, the second embodiment will be described. In the second embodiment, the parts that are not particularly described are the same as those in the first embodiment.
The oil-based inkjet ink according to the present embodiment (hereinafter sometimes simply referred to as ink) includes an encapsulated pigment containing a pigment and a urethane compound that coats the surface of the pigment, and a non-aqueous solvent. A compound having a urethane skeleton and a side chain and insoluble in a non-aqueous solvent, wherein the side chain of the urethane compound is an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, And one or more selected from the group consisting of nitrile groups and an alkoxysilyl group.
According to this embodiment, it is excellent in the repellency with respect to a nozzle plate, can prevent deterioration of a nozzle plate, can reduce the image see-through of a printed matter, and can raise an image density.

  The ink of this embodiment includes an encapsulated pigment and a non-aqueous solvent, and the encapsulated pigment includes a pigment and a urethane compound that coats the surface of the pigment. The solubility of the non-aqueous solvent, the pigment, and the urethane compound in the non-aqueous solvent is as described in the first embodiment. Further, as in the first embodiment, the ink may contain a pigment dispersant and various additives.

A urethane compound has a side chain with a urethane skeleton. This side chain is one or more selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group (hereinafter referred to as side chain A). And an alkoxysilyl group (hereinafter sometimes referred to as a side chain B).
Since the urethane compound contains an amino group in the main chain, the urethane compound has a property that is biased toward basicity and a flexible structure that is extensible. By including an alkoxysilyl group in the urethane compound, the alkoxysilyl group forms a siloxane bond during the solvent removal process, and the resin is cross-linked on the surface of the encapsulated pigment, thereby improving the scratch resistance of the printed matter. be able to.

The urethane compound preferably contains a plurality of alkoxysilyl groups, and at least a part of the plurality of alkoxysilyl groups preferably forms a siloxane bond.
As the alkoxysilyl group, one or more selected from the group consisting of a monoalkoxysilyl group, a dialkoxysilyl group, and a trialkoxysilyl group can be used.
The alkoxysilyl group is, for example, a functional group represented by the general formula “—Si (R ¹ ) (R ² ) (R ³ )”.
In the above general formula, R ¹ , R ² , and R ³ are each independently an alkoxy group having 1 to 10 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or a hydrogen atom,
It is preferable that at least one of R ¹ , R ² , and R ³ is an alkoxy group having 1 to 10 carbon atoms, particularly 1 to 4 carbon atoms.
Examples of the alkoxy group having 1 to 10 carbon atoms include methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, pentoxy group, methyl-n-butoxy group, methyl-n-butoxy group, dimethyl-n. -Propoxy group, ethyl-n-propoxy group, hexyloxy group, methyl-n-pentyloxy group, 1,1-dimethyl-n-butoxy group, 1,2-dimethyl-n-butoxy group, dimethyl-n-butoxy Group, ethyl-n-butoxy group, trimethyl-n-propoxy group, ethyl-methyl-n-propoxy group and the like. Preferably, the alkoxy group has 1 to 4 carbon atoms.
Examples of the alkyl group having 1 to 10 carbon atoms include methyl group, ethyl group, propyl group, isopropyl group, cyclopropyl group, butyl group, isobutyl group, cyclobutyl group, methyl-cyclopropyl group, pentyl group, and methyl-n-butyl. Group, dimethyl-n-propyl group, ethyl-n-propyl group, cyclopentyl group, methyl-cyclobutyl group, dimethyl-cyclopropyl group, ethyl-cyclopropyl group, hexyl group, methyl-n-pentyl group, dimethyl-n- Butyl group, ethyl-n-butyl group, trimethyl-n-propyl group, ethyl-methyl-n-propyl group, cyclohexyl group, methyl-cyclopentyl group, ethyl-cyclobutyl group, dimethyl-cyclobutyl group, propyl-cyclopropyl group, Isopropyl-cyclopropyl group, trimethyl-cyclopro Group, ethyl - methyl - can be exemplified cyclopropyl group. Preferably, the alkyl group has 1 to 4 carbon atoms.

Preferred alkoxysilyl groups include, for example,
Trimethoxysilyl group, triethoxysilyl group, triisopropoxysilyl group, methyldimethoxysilyl group, methyldiethoxysilyl group, ethyldimethoxysilyl group, ethyldiethoxysilyl group, phenyldimethoxysilyl group, dimethylmethoxysilyl group, dimethoxyphenyl Silyl group, 2- (trimethoxysilyl) ethyl group, 3- (trimethoxysilyl) propyl group, 4- (trimethoxysilyl) butyl group, 6- (trimethoxysilyl) hexyl group, 2- (triethoxysilyl) Ethyl group, 3- (triethoxysilyl) propyl group, 4- (triethoxysilyl) butyl group, 2- (dimethoxymethylsilyl) ethyl group, 3- (dimethoxymethylsilyl) propyl group, 4- (dimethoxymethylsilyl) Butyl group, 2- (diethoxymethylsilyl) Ethyl group, 3- (diethoxymethylsilyl) propyl group, 4- (diethoxymethylsilyl) butyl group, 2- (dimethoxyethylsilyl) ethyl group, 2- (diethoxyethylsilyl) ethyl group, 2- (diethyl) A methoxysilyl) ethyl group, a 2- (dimethylethoxysilyl) ethyl group, and the like.
These may be contained alone or in plural types in one urethane compound.

  As the urethane compound, for example, a compound including a main chain composed of a urethane skeleton and a side chain graft-polymerized to the main chain can be used. Here, what was obtained by making polyhydric isocyanate and polyhydric alcohol react can be used for urethane frame | skeleton.

The urethane compound has a structure in which units derived from a polyvalent isocyanate and units derived from a polyhydric alcohol are alternately arranged, the unit derived from a polyhydric alcohol includes a unit derived from an alkanolamine, and the side chain A of the urethane compound However, what couple | bonded through the nitrogen atom of the unit derived from alkanolamine can be used.
Such a urethane compound can be obtained by reacting a polyvalent isocyanate with an alkanolamine or a derivative thereof.

As the alkanolamine, monoalkanolamine, dialkanolamine, and derivatives thereof can be used singly or in combination of two or more as in the first embodiment.
Preferably, the alkanolamine is at least one selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group (side chain A). A compound in which Michael is added to an alkanolamine can be used. Details are as described in the first embodiment.

As in the first embodiment, the polyvalent isocyanate is a compound having two or more isocyanate groups, and aliphatic polyisocyanate, alicyclic polyisocyanate, aromatic polyisocyanate, etc. alone or 2 A combination of more than one species can be used.
Similarly to the first embodiment, the urethane compound may further include units derived from other polyhydric alcohols other than alkanolamine, in addition to units derived from polyvalent isocyanate and units derived from alkanolamine.

  The urethane compound is preferably 0.01 to 30% by mass, more preferably 1 to 20% by mass, based on the total amount of ink.

In the present embodiment, the urethane compound further includes an alkoxysilyl group (side chain B) as a side chain.
A method for introducing an alkoxysilyl group into a urethane compound will be described below.

(1) Alkanolamine-derived alkoxysilyl group-containing urethane compound The alkanolamine-derived alkoxysilyl group-containing urethane compound has, for example, a structure in which units derived from a polyvalent isocyanate and units derived from a polyhydric alcohol are alternately arranged. ,
The alkanolamine-derived unit is a Michael addition of a compound having at least one selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group. The alkanolamine-derived unit A and the alkanolamine-derived unit B having an alkoxysilyl group are included.

  The alkanolamine-derived unit B having an alkoxysilyl group includes an alkanolamine-derived unit B1 obtained by Michael addition of a compound having an alkoxysilyl group and an unsaturated double bond, and a compound having an alkoxy group and an epoxy group. It preferably contains one or more selected from the group consisting of alkanolamine-derived units B2 into which alkoxy groups have been introduced by reaction.

As one method for producing this alkoxysilyl group-containing urethane compound, for example, an alkanolamine derivative obtained by Michael addition of a compound having a side chain A to an alkanolamine (hereinafter referred to as alkanolamine derivative A), an alkoxysilyl group, In this method, an alkanolamine derivative B1 obtained by Michael addition of a compound having an unsaturated double bond to an alkanolamine (hereinafter referred to as alkanolamine derivative B1) is reacted with a polyvalent isocyanate.
The alkanolamine derivative A and the polyvalent isocyanate are as described in the first embodiment.

As the alkanolamine derivative B1, a compound in which a compound having an alkoxysilyl group and an unsaturated double bond is added to an alkanolamine by Michael can be used. The kind of alkanolamine and the method of Michael addition are as described in the first embodiment.
As the unsaturated double bond, for example, a vinyl group, an acryloyl group, an acrylamide group, an acryloyloxy group, or the like can be used.

As a compound having an alkoxysilyl group and an unsaturated double bond, for example,
3-acryloxypropyltrimethoxysilane,
Acryloxymethyltrimethoxysilane,
Acryloxymethylmethyldimethoxysilane,
Acryloxymethyltriethoxysilane,
Acryloxymethylmethyldiethoxysilane,
Vinyltrimethoxysilane,
Vinyltriethoxysilane,
Vinyldimethoxymethylsilane,
Vinyldiethoxymethylsilane,
Vinyltris (2-methoxyethoxy) silane or the like can be preferably used.
These can be used alone or in combination of two or more.

Other methods for producing this alkoxysilyl group-containing urethane compound include, for example, an alkanolamine derivative (alkanolamine derivative A) obtained by Michael addition of a compound having a side chain A to an alkanolamine, an alkoxysilyl group, and an epoxy-containing group. In this method, an alkanolamine derivative B2 (hereinafter referred to as alkanolamine derivative B2) in which an alkoxysilyl group is introduced into an alkanolamine is reacted with a polyvalent isocyanate.
The alkanolamine derivative A and the polyvalent isocyanate are as described in the first embodiment.

As the alkanolamine derivative B2, a compound obtained by reacting a compound having an alkoxysilyl group and an epoxy-containing group with an alkanolamine can be used. The type of alkanolamine is as described in the first embodiment.
As the epoxy group-containing group, an epoxy group, a glycidyl group, a glycidoxy group, or the like can be used.

As a compound having an alkoxysilyl group and an epoxy group-containing group, for example,
3-glycidoxypropyltrimethoxysilane,
3-glycidoxypropyltriethoxysilane,
3-glycidoxypropylmethyldimethoxysilane,
3-Glycidoxypropylmethyldiethoxysilane or the like can be preferably used.
These can be used alone or in combination of two or more.

(1) In the alkanolamine-derived alkoxysilyl group-containing urethane compound,
The content of the alkoxysilyl group relative to the entire urethane compound is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and still more preferably 1.0% in terms of alkoxysilyl group-containing alkanolamine. It is at least mass%. This can further improve the scratch resistance and fixability of the printed matter.
On the other hand, the content of the alkoxysilyl group with respect to the entire urethane compound is preferably 20% by mass or less, more preferably 11% by mass or less, and further preferably 5% by mass or less, in terms of alkoxysilyl group-containing alkanolamine. is there. Thereby, the flexibility of the urethane compound can be secured, the coating property of the pigment can be improved, and the wipe durability and the image density can be improved.

(1) In the alkanolamine-derived alkoxysilyl group-containing urethane compound,
The content of the side chain A with respect to the entire urethane compound is preferably 10% by mass or more, more preferably 20% by mass or more, and further preferably 25% by mass or more in terms of the side chain A-containing alkanolamine.
On the other hand, in the alkanolamine-derived alkoxysilyl group-containing urethane compound,
The content of the side chain A with respect to the entire urethane compound is preferably 50% by mass or less, more preferably 40% by mass or less, in terms of the side chain A-containing alkanolamine.
When there are a plurality of types of side chains A, the total content.

  The urethane compound has, as the side chain A, a first side chain having an aromatic ring and a second side having a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, or a nitrile group. It is preferable to have a chain. The first side chain and the second side chain are preferably in a molar ratio of 25:75 to 75:25.

(1) In the alkanolamine-derived alkoxysilyl group-containing urethane compound,
The total content of the alkoxysilyl group and side chain A with respect to the entire urethane compound is preferably 10 to 55% by mass, more preferably 20 to 20% in terms of alkoxysilyl group-containing alkanolamine and side chain A-containing alkanolamine. 45% by mass.

(2) Mercapto compound-derived alkoxysilyl group-containing urethane compound The mercapto compound-derived alkoxysilyl group-containing urethane compound has, for example, a structure in which units derived from a polyisocyanate and units derived from a polyhydric alcohol are alternately arranged. ,
The unit derived from a polyhydric alcohol is a compound having at least one selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group. Unit alkanolamine-derived unit A added,
An alkoxysilyl group is introduced into the isocyanate group of a urethane compound via a mercapto group.

One method for producing this mercapto compound-derived alkoxysilyl group-containing urethane compound is, for example, an alkanolamine derivative obtained by Michael addition of a compound having a side chain A to an alkanolamine (hereinafter referred to as alkanolamine derivative A), and many. It reacts with a polyvalent isocyanate to obtain a urethane compound, then reacts the urethane compound with a compound (mercapto compound) containing a mercapto group and an alkoxysilyl group, and the mercapto compound mercapto is based on the isocyanate group of the urethane compound. This is a method in which groups are reacted and bonded.
The alkanolamine derivative A and the polyvalent isocyanate are as described in the first embodiment.

As a compound containing a mercapto group and an alkoxysilyl group, for example,
3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 3-mercaptopropyl (diethoxy) methylsilane and the like can be preferably used.
These can be used alone or in combination of two or more.

(2) As a method for producing a mercapto compound-derived alkoxysilyl group-containing urethane compound,
The alkanolamine derivative A, polyvalent isocyanate, and mercapto compound can be obtained by reacting in an aprotic solvent by optionally adding a catalyst. Alternatively, the alkanolamine derivative A and the polyvalent isocyanate may be reacted, and then the mercapto compound may be reacted with the isocyanate group of the obtained urethane compound.

(2) In the mercapto compound-derived alkoxysilyl group-containing urethane compound,
The content of the alkoxysilyl group with respect to the entire urethane compound is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and still more preferably 1.0% in terms of an alkoxysilyl group-containing mercapto compound. It is at least mass%. This can further improve the scratch resistance and fixability of the printed matter.
On the other hand, the content of the alkoxysilyl group with respect to the entire urethane compound is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less in terms of an alkoxysilyl group-containing mercapto compound. is there. Thereby, the flexibility of the urethane compound can be secured, the coating property of the pigment can be improved, and the wipe durability and the image density can be improved.

  (2) In the mercapto compound-derived alkoxysilyl group-containing urethane compound, the content of the side chain A, the molar ratio of the first side chain to the second side chain in the side chain A, the alkoxysilyl group and the side chain A The preferable range of the total content of is the same as the above (1) alkanolamine-derived alkoxysilyl group-containing urethane compound.

(3) Isocyanate compound-derived alkoxysilyl group-containing urethane compound The isocyanate compound-derived alkoxysilyl group-containing urethane compound has, for example, a structure in which units derived from a polyvalent isocyanate and units derived from a polyhydric alcohol are alternately arranged. ,
The unit derived from a polyhydric alcohol is a compound having at least one selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group. Unit alkanolamine-derived unit A added,
An alkoxysilyl group is introduced into the hydroxy group of a urethane compound via an isocyanate group.

One method for producing this isocyanate compound-derived alkoxysilyl group-containing urethane compound is, for example, an alkanolamine derivative obtained by Michael addition of a compound having a side chain A to an alkanolamine (hereinafter referred to as alkanolamine derivative A), and many. It reacts with a polyvalent isocyanate to obtain a urethane compound, then reacts the urethane compound with a compound containing an isocyanate group and an alkoxysilyl group (isocyanate compound), and the isocyanate compound of the isocyanate compound is based on the hydroxy group of the urethane compound. This is a method in which groups are reacted and bonded. The hydroxy group of the urethane compound includes a hydroxy group derived from an alkanolamine, a hydroxy group derived from an optionally added polyhydric alcohol, a hydroxy group introduced into an alkanolamine derivative, and the like.
The alkanolamine derivative A and the polyvalent isocyanate are as described in the first embodiment.

As a compound containing an isocyanate group and an alkoxysilyl group, for example,
3-isocyanatopropyltriethoxysilane, 3-isocyanatopropyltrimethoxysilane and the like can be preferably used.
These can be used alone or in combination of two or more.

(3) As a production method of an isocyanate compound-derived alkoxysilyl group-containing urethane compound,
The alkanolamine derivative A, the polyvalent isocyanate, and the isocyanate compound can be obtained by reacting in an aprotic solvent, optionally adding a catalyst. Alternatively, the alkanolamine derivative A and the polyvalent isocyanate may be reacted, and then the isocyanate compound may be reacted with the hydroxy group of the obtained urethane compound.

(3) In the isocyanate compound-derived alkoxysilyl group-containing urethane compound,
The content of the alkoxysilyl group with respect to the entire urethane compound is preferably 0.01% by mass or more, more preferably 0.1% by mass or more, and still more preferably 1.0% in terms of the alkoxysilyl group-containing isocyanate compound. It is at least mass%. This can further improve the scratch resistance and fixability of the printed matter.
On the other hand, the content of the alkoxysilyl group with respect to the entire urethane compound is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 3% by mass or less, in terms of alkoxysilyl group-containing isocyanate compound. is there. Thereby, the flexibility of the urethane compound can be secured, the coating property of the pigment can be improved, and the wipe durability and the image density can be improved.

  (3) In the isocyanate compound-derived alkoxysilyl group-containing urethane compound, the content of the side chain A, the molar ratio of the first side chain to the second side chain in the side chain A, the alkoxysilyl group and the side chain A The preferable range of the total content of is the same as the above (1) alkanolamine-derived alkoxysilyl group-containing urethane compound.

  Hereinafter, the present invention will be described in detail with reference to examples. The present invention is not limited to the following examples.

"Production Example A"
Hereinafter, Examples 1 to 20 and Comparative Examples 1 to 4 will be described as Production Example A.
<Synthesis of diol>
Table 1 shows the raw material composition of the diol.
In a 300 mL four-necked flask, 105.1 g of diethanolamine (molecular weight (Mw) 105.1) was charged, and the temperature was raised to 110 ° C. with aeration and stirring of nitrogen gas. The monomer shown in Table 1 was dripped at this over 30 minutes with each compounding quantity. The Michael addition reaction was completed at 110 ° C. for 2 hours to obtain a liquid diol.

The components shown in Table 1 are as follows.
Diethanolamine: NH (C ₂ H ₄ OH) ₂ , “DEA” manufactured by Nippon Shokubai Co., Ltd.
Benzyl acrylate: “Biscoat # 160” manufactured by Osaka Organic Chemical Industry Co., Ltd.
Tetrahydrofurfuryl acrylate: “Biscoat # 150” manufactured by Osaka Organic Chemical Industry Co., Ltd.
Acryloylmorpholine: “ACMO” manufactured by KJ Chemicals.
Acrylic acid: “AA” manufactured by Nippon Shokubai Co., Ltd.
Dimethylacrylamide: “DMAA” manufactured by KJ Chemicals.
Diethylacrylamide: “DEAA” manufactured by KJ Chemicals.
Dimethylaminopropylacrylamide: “DMAPAA” manufactured by KJ Chemicals.

1H, 1H, 2H, 2H-Tridecafluoroacrylate: “Biscoat 13F” manufactured by Osaka Organic Chemical Industry Co., Ltd.
1H, 1H, 5H-octafluoropentyl acrylate: “Biscoat 8F” manufactured by Osaka Organic Chemical Industry Co., Ltd.
2,2,3,3-tetrafluoropropyl acrylate: “Biscoat 4F” manufactured by Osaka Organic Chemical Industry Co., Ltd.
Methoxy polyethylene glycol (PEG9) acrylate: Comparison _{monomer, CH 2 = CH-CO- (} OCH 2 -CH 2) 9 -OCH 3, manufactured by NOF Corporation, "AME-400".
n-octyl acrylate: Comparative monomer, CH ₂ ═CH—CO—O—C ₈ H ₁₇ , “NOAA” manufactured by Osaka Organic Chemical Industries, Ltd.
Acrylic nitrile: Wako Pure Chemical Industries, Ltd.
Dimethylaminoethyl acrylate: “Aron DA” manufactured by Toagosei Co., Ltd.

<Synthesis of urethane compounds>
Tables 2, 4, and 6 show the raw material composition of the urethane compound.
A 300 mL four-necked flask was charged with the diol solution obtained above and propylene glycol as the other diol component, 0.15 g of dibutyltin dilaurate was added as a tin catalyst, and nitrogen gas was bubbled and stirred. The temperature was raised to ° C. And the mixture of diisocyanate and methyl ethyl ketone (MEK) was dripped over 30 minutes. After the dropwise addition, the mixture was reacted at a temperature of 78 ° C. to 80 ° C. for 24 hours and then cooled to obtain a resin solution having a solid content of 50.0% by mass. The weight average molecular weight (Mw; GPC method, standard polystyrene conversion) is shown in each table.

The components shown in each table are as follows.
Hexamethylene diisocyanate: OCN— (CH ₂ ) ₆ —NCO, manufactured by Wako Pure Chemical Industries, Ltd.
Xylene diisocyanate: OCN—CH ₂ —C ₆ H ₄ —CH ₂ —NCO, “Takenate 500” manufactured by Mitsui Chemicals, Inc.
Propylene glycol: Wako Pure Chemical Industries, Ltd.
Tin catalyst: Dibutyltin dilaurate, “L-101” manufactured by Tokyo Fine Chemical Co., Ltd.
MEK: Methyl ethyl ketone, manufactured by Wako Pure Chemical Industries, Ltd.

<Ink preparation>
Tables 3, 5 and 7 show the ink formulations.
According to the blending amount shown in each table, the resin solution obtained above, the pigment “MOGUL L”, the pigment dispersant “Hypermer KD12”, methyl oleate, Exol D130, and methyl ethyl ketone “MEK” were mixed, and zirconia beads (diameter 0.5 mm) and dispersed with a rocking mill (Seiwa Giken Co., Ltd.) at 67.50 Hz for 120 minutes. After dispersion, the zirconia beads were removed, and the low boiling point solvent (methyl ethyl ketone) of the dispersion was removed using an evaporator while heating and reducing the pressure. Subsequently, the obtained dispersion was cooled and irradiated with ultrasonic waves for 10 minutes using an ultrasonic homogenizer (SONIC & MATERIALS, INC., VC750) while stirring. Thus, the pigment was encapsulated with the urethane compound to obtain an ink containing the encapsulated pigment.

The components shown in each table are as follows.
Pigment: Carbon black, “MOGUL L” manufactured by Cabot Specialty Chemicals, Inc.
Pigment dispersant: Comb amine dispersant, “Hypermer KD12” manufactured by Croda Japan Co., Ltd.
Methyl oleate: CH ₃ (CH ₂ ) ₇ CH═CH (CH ₂ ) ₇ COOCH ₃ , Tokyo Chemical Industry Co., Ltd.
Petroleum hydrocarbon solvent: Naphthenic solvent, “Exsol D130” manufactured by TonenGeneral Sekiyu KK

Except for the following points, inks of Examples and Comparative Examples were prepared according to the above-described method.
In Example 18, the ink solvent was only methyl oleate.
In Comparative Example 1, the resin solution was not used and the pigment was not encapsulated with the urethane compound.
In Comparative Examples 2 and 4, resins 20 and 21 having high miscibility with the ink solvent were used as the resin of the resin solution.
In Comparative Example 3, a resin 21 in which no diol was used and no side chain was introduced into the urethane compound was used.

The urethane compound used in each example and each comparative example is completely dissolved in 100 g of the non-aqueous solvent used in each example and each comparative example (a mixture when two or more kinds of non-aqueous solvents are used). Mass (g / 100g) was measured and the solubility of the urethane compound (resins 1-22) was calculated | required.
As a result, in each Example, the solubility of each resin with respect to 100 g of the non-aqueous solvent was less than 1 g / 100 g. In Comparative Example 3, the solubility of the resin 21 with respect to 100 g of the non-aqueous solvent was less than 1 g / 100 g.
In Comparative Examples 2 and 4, the solubility of the resins 20 and 22 was more than 5 g / 100 g with respect to 100 g of the non-aqueous solvent, respectively. Resins 20 and 22 were miscible with non-aqueous solvents.

<Evaluation>
The inks of the above examples and comparative examples were evaluated by the following methods. These evaluation results are shown in Table 3, Table 5, and Table 7.

(1) Wettability to the nozzle plate Each ink is placed in a 30 ml glass container, and the nozzle plate (length: 5 mm, width: 5 mm) used in the inkjet printer “Orifice EX9050” (trade name: manufactured by Riso Kagaku Co., Ltd.) One side was pinched with tweezers, and 2 cm from one side on the opposite side was immersed in the ink for 5 seconds. Thereafter, the nozzle plate was quickly pulled up, and the time t until the ink film remaining on the nozzle plate became ink droplets was measured. The same operation was repeated 10 times using the same nozzle plate, and each time t was measured. The average value was calculated and used as the ink repellent time, and evaluated according to the following criteria.
AA: The ink repellent time is less than 1 second.
A: The ink repellent time is 1 second or more and less than 3 seconds.
B: The ink repellent time is 3 seconds or more and less than 4 seconds.
C: The ink repellent time is 4 seconds or more.

(2) Wipe Durability Head cleaning was carried out 1000 times by normal cleaning of head maintenance using an inkjet printer “Orifice EX9050” (trade name: manufactured by Riso Kagaku Kogyo Co., Ltd.). After 1000 times of head cleaning, the ink repellency of the nozzle plate portion in contact with the wiping blade was visually evaluated.
AA: Ink repellency is maintained at all the portions where the wiping blade is in contact. Immediately after the test, the ink is completely repelled.
A: Ink repellency is maintained at all the portions where the wiping blade is in contact.
After the test, it takes a few seconds for the ink to completely repel.
B: The ink repellency of the part which the wiping blade contacted has fallen.
C: The ink repellency of all the parts that are in contact with the wiping blade is lowered.

(3) Image density and image see-through Using an inkjet head mounted on an inkjet printer “Orifice EX9050”, per pixel per pixel at a resolution of 600 dpi × 600 dpi on plain paper (Ideal Paper Multi, produced by Riso Kagaku Corporation) , 12 pl solid image was printed. One day after printing, an optical densitometer (RD920, manufactured by Macbeth) was used to measure the OD value (table OD value) of the printed material surface and the OD value (back OD value) of the back surface of the printed material. The image density was evaluated from the table OD value according to the following criteria. Image back-through was evaluated from the back OD value according to the following criteria.
(Image density)
AA: The OD value is 1.15 or more.
A: The OD value is 1.10 or more and less than 1.15.
B: The OD value is 1.00 or more and less than 1.10.
C: The OD value is less than 1.00.
(Image strikethrough)
AA: OD value is less than 0.10.
A: The OD value is 0.10 or more and less than 0.20.
B: The OD value is 0.20 or more and less than 0.30.
C: The OD value is 0.30 or more.

(4) Scratch resistance (coated paper)
Each ink was loaded into a line-type ink jet printer “OLIFIS EX9050” (manufactured by Riso Kagaku Co., Ltd.), and a solid image was printed on high-quality coated paper “Aurora Coat” (manufactured by Nippon Paper Industries Co., Ltd.) to obtain a printed matter. . Printing was performed at a resolution of 300 × 300 dpi under an ejection condition where the ink amount per dot was 42 pl. Note that the “Orifice EX 9050” is a system that uses a line-type inkjet head and conveys paper in the sub-scanning direction orthogonal to the main scanning direction (the direction in which the nozzles are arranged) to perform printing.
After standing for 24 hours after printing, the state when the solid image portion of the printed material was strongly rubbed with a finger five times was visually observed, and the scratch resistance was evaluated according to the following criteria.
A: Image peeling is hardly observed.
B: Although some peeling of the image is confirmed, there is no problem in actual use.
C: Image peeling is remarkable and there is a problem in actual use.

(5) Fixability (glass surface)
Each ink was evenly applied to the slide glass “White Edge Polish No. 1” (manufactured by Matsunami Glass Industry Co., Ltd.) with a wire bar “# 4”, placed in a thermostat set at 100 ° C., dried for 3 minutes, and 5 ° C. at room temperature. After being left for a minute, a finger touch drying test was conducted to evaluate the fixability of the ink film to the glass surface.
The ink-applied portion was touched with a finger and visually observed, and the fixability to the glass surface was evaluated according to the following criteria.
Tack is an index representing the degree of stickiness.
A: There is no ink on the finger and no tack.
B: The finger does not get ink, but there is tack.
C: The finger is inked.

(6) Storage stability (70 ° C, 1 month)
First, the viscosity of the ink immediately after ink preparation was measured.
The ink was then placed in a 10 ml screw-vial bottle and left at 70 ° C. for 1 month.
Thereafter, the ink was sampled and the ink viscosity was measured.
The viscosity was measured at room temperature (23 ° C.) with a cone angle of 2 ° and a diameter of 40 mm using a rheometer ARG2 (manufactured by TI Instruments).
From the ink viscosity before and after standing for 1 month, the rate of change in viscosity was determined by the following formula, and the storage stability was evaluated according to the following criteria.
Viscosity change rate (%) = 100− (ink viscosity after standing (mPa · s) / ink viscosity immediately after preparation (mPa · s)) × 100
A: Viscosity change rate is within ± 5%.
A ⁻ : Viscosity change rate is within ± 7%.
B: Viscosity change rate is less than ± 10%.
C: Viscosity change rate is ± 10% or more.

As shown in each table, the inks of the respective examples had good wettability and wipe durability with respect to the nozzle plate, and prevented image print-through from being achieved, thereby obtaining a high image density.
In Examples 1 to 4, encapsulated pigments were prepared using various diols and urethane compounds having various side chains, and good results were obtained. When the polarity of the diol is increased, the solvent detachability is promoted, the back-through is reduced, and the wettability to the nozzle plate is also improved.

In Examples 5 to 7, encapsulated pigments were prepared using urethane compounds having various side chains together with benzyl groups, and wettability and wipe durability with respect to the nozzle plate were further improved, and image see-through was reduced. The image density became high.
In Examples 8 to 10, 19, and 20, encapsulated pigments were prepared using a urethane compound having a nitrogen-containing group, and good results were obtained. It has been found that when the urethane compound contains a nitrogen-containing group, the wipe durability is further improved, the image see-through is reduced, and the image density is increased.

In Examples 11 to 13, encapsulated pigments were prepared using a urethane compound having a nitrogen-containing group together with a benzyl group, and good results were obtained. In Examples 11-12, the wettability with respect to the nozzle plate was further improved.
In Examples 14 to 16, encapsulated pigments were prepared using a urethane compound containing a fluoroalkyl group, and good results were obtained. In Examples 14 to 16, it was possible to improve the scratch resistance to the coated paper and the fixability to the glass surface, and to impart further functionality.

In Example 17, an encapsulated pigment was prepared using urethane compounds having different urethane skeletons as compared to Example 3, and good results were obtained.
Example 18 was different from Example 3 in the non-aqueous solvent of the ink, and good results were obtained.

In Comparative Example 1, no urethane compound was contained and the pigment was not encapsulated, and sufficient results were not obtained.
In Comparative Example 2, an encapsulated pigment was prepared using a urethane compound having a methoxypolyethylene glycol chain, and the urethane compound showed miscibility in a non-aqueous solvent, and the result of image see-through and image density of printed matter was poor. It was enough.
In Comparative Example 3, the pigment was encapsulated with a urethane compound containing no side chain, and sufficient results were not obtained. In Comparative Example 3, wettability and wipe durability with respect to the nozzle plate were particularly inferior.
In Comparative Example 4, an encapsulated pigment was prepared using a urethane compound having an octyl chain, and the urethane compound showed miscibility with a non-aqueous solvent, and the results of image show-through and image density of the printed matter were insufficient. there were.

"Production example B"
Hereinafter, Examples B1 to B12 and Comparative Example B1 will be described as Production Example B. Components not specifically described are the same as those in Production Example A.
<Synthesis of diol>
Table 8 shows the raw material composition of the diol.
In a 300 mL four-necked flask, 105.1 g of diethanolamine (molecular weight (Mw) 105.1) was charged, and the temperature was raised to 110 ° C. with aeration and stirring of nitrogen gas. The monomer shown in Table 8 was dripped at this over 30 minutes with each compounding quantity. The reaction was completed at 110 ° C. for 2 hours to obtain a liquid diol.

The components shown in Table 8 are as follows.
Diethanolamine: NH (C ₂ H ₄ OH) ₂ , “DEA” manufactured by Nippon Shokubai Co., Ltd.
Benzyl acrylate: “Biscoat # 160” manufactured by Osaka Organic Chemical Industry Co., Ltd.
Acryloylmorpholine: “ACMO” manufactured by KJ Chemicals.
Dimethylacrylamide: “DMAA” manufactured by KJ Chemicals.
3-acryloxypropyltrimethoxysilane: “KBM-5103” manufactured by Shin-Etsu Chemical Co., Ltd.
3-Glycidoxypropyltrimethoxysilane: “KBM-403” manufactured by Shin-Etsu Chemical Co., Ltd.
Methoxy polyethylene glycol (PEG9) acrylate: Comparison _{monomer, CH 2 = CH-CO- (} OCH 2 -CH 2) 9 -OCH 3, manufactured by NOF Corporation, "AME-400".

<Synthesis of urethane compounds>
In Table 9, the raw material composition of resin B1-B6 is shown as a urethane compound.
In accordance with the formulation shown in the table, diol solution B4 obtained above, diol solutions B1 to B3, and propylene glycol as other diol components were charged into a 300 mL four-necked flask, and dibutyltin dilaurate was added as a tin catalyst. 0.15g was added, and it heated up to 78 degreeC, carrying out nitrogen gas bubbling and stirring. And the mixture of bivalent isocyanate and methyl ethyl ketone (MEK) was dripped over 30 minutes. After the dropwise addition, the mixture was reacted at a temperature of 78 ° C. to 80 ° C. for 24 hours and then cooled to obtain a resin solution having a solid content of 50.0% by mass. The weight average molecular weight (Mw; GPC method, standard polystyrene conversion) is shown in the table.

In Table 11, the raw material composition of resin B7-B13 is shown as a urethane compound.
In resins B7 to B9, in accordance with the formulation shown in the table, in a 300 mL four-necked flask, 3-mercaptopropyltrimethoxysilane, the diol solutions B1 to B3 obtained above, and propylene glycol as other diol components The resin solution having a solid content of 50.0% by mass was obtained in the same manner as the resin B1 except that was charged.
For Resin B10, a resin solution with a solid content of 50.0 mass% was obtained in the same manner as Resin B1 except that diol solution B4 was changed to diol solution B5 according to the formulation shown in the table.
In resin B11, according to the prescription shown in the table, 3-isocyanatepropyltriethoxysilane, the diol solutions B1 to B3 obtained above, and propylene glycol as other diol components were charged into a 300 mL four-necked flask. Otherwise, a resin solution having a solid content of 50.0% by mass was obtained in the same manner as the resin B1.
Resin B12 was the same as Resin B1 except that propylene glycol was charged as a diol component B1-B3 obtained above and other diol components in a 300 mL four-necked flask according to the formulation shown in the table. Thus, a resin solution having a solid content of 50.0% by mass was obtained.
In the resin B13, according to the formulation shown in the table, a 300 mL four-necked flask was prepared in the same manner as the resin B1 except that the diol solution B6 obtained above and propylene glycol as other diol components were charged. A resin solution having a solid content of 50.0% by mass was obtained.

The components shown in each table are as follows.
3-mercaptopropyltrimethoxysilane (Mw196.4): “KBM-803” manufactured by Shin-Etsu Chemical Co., Ltd.
Diol 53-isocyanatopropyltriethoxysilane (Mw274.4): “KBE-9007” manufactured by Shin-Etsu Chemical Co., Ltd.
Hexamethylene diisocyanate: OCN— (CH ₂ ) ₆ —NCO, Mw 168.2, manufactured by Wako Pure Chemical Industries, Ltd.
Xylene diisocyanate: OCN—CH ₂ —C ₆ H ₄ —CH ₂ —NCO, Mw 188.18, “Takenate 500” manufactured by Mitsui Chemicals, Inc.
Propylene glycol: Mw 76.1, manufactured by Wako Pure Chemical Industries, Ltd.
Tin catalyst: Dibutyltin dilaurate, “L-101” manufactured by Tokyo Fine Chemical Co., Ltd.
MEK: Methyl ethyl ketone, manufactured by Wako Pure Chemical Industries, Ltd.

<Ink preparation>
Tables 10 and 12 show the ink formulations.
According to the blending amount shown in each table, the resin solution obtained above, the pigment “MOGUL L”, the pigment dispersant “Hypermer KD11”, methyl oleate, Exol D130, and methyl ethyl ketone “MEK” were mixed, and zirconia beads (diameter 0.5 mm) and dispersed with a rocking mill (Seiwa Giken Co., Ltd.) at 67.50 Hz for 120 minutes. After dispersion, the zirconia beads were removed, and the low boiling point solvent (methyl ethyl ketone) of the dispersion was removed using an evaporator while heating and reducing the pressure. Subsequently, the obtained dispersion was cooled and irradiated with ultrasonic waves for 10 minutes using an ultrasonic homogenizer (SONIC & MATERIALS, INC., VC750) while stirring. Thus, the pigment was encapsulated with the urethane compound to obtain an ink containing the encapsulated pigment.

The components shown in each table are as follows.
MOGUL L: Carbon black, “MOGUL L” manufactured by Cabot Specialty Chemicals, Inc.
Raven 1035: “Raven 1035” manufactured by Aditya Birla.
HYPERMER KD11: “HYPERMER KD11” manufactured by Croda Japan Co., Ltd.
SOLPERSE 28000: "SOLSPERSE 28000" manufactured by Lubrizol Japan.
Methyl oleate: CH ₃ (CH ₂ ) ₇ CH═CH (CH ₂ ) ₇ COOCH ₃ , Tokyo Chemical Industry Co., Ltd.
Isopropyl myristate: “IPM-R” manufactured by Higher Alcohol Industry Co., Ltd.
Petroleum hydrocarbon solvent: Naphthenic solvent, “Exsol D130” manufactured by TonenGeneral Sekiyu KK
Oleyl alcohol: “Oleyl alcohol VP” manufactured by Higher Alcohol Industry Co.

Except for the following points, inks of Examples and Comparative Examples were prepared according to the above-described method.
In Example B11 and Example B12, inks were prepared by changing the solvent and the dispersant.
In Example B13, an ink was prepared using the diol B1 and the diol B3, and the resin B12 not containing an alkoxysilyl group.
In Comparative Example B1, diol B6 was prepared using a comparative monomer, and ink was prepared using a resin B13 that does not contain an alkoxysilyl group.

The urethane compound used in each example and each comparative example is completely dissolved in 100 g of the non-aqueous solvent used in each example and each comparative example (a mixture when two or more kinds of non-aqueous solvents are used). Mass (g / 100g) was measured and the solubility of the urethane compound (resins 1-22) was calculated | required.
As a result, in each Example, the solubility of each resin with respect to 100 g of the non-aqueous solvent was less than 1 g / 100 g.
In Comparative Example B1, the solubility of the resin B13 with respect to 100 g of the non-aqueous solvent was more than 5 g / 100 g. Resin B13 exhibited miscibility with non-aqueous solvents.

<Evaluation>
The inks of the examples and comparative examples were evaluated by the same method as in Production Example A. These evaluation results are shown in Tables 10 and 12.

As shown in each table, the inks of the respective examples had good wettability and wipe durability with respect to the nozzle plate, and prevented image print-through from being achieved, thereby obtaining a high image density.
Through each example, it was found that the scratch resistance and fixability were further improved as compared to the case of using the urethane compound containing no alkoxysilyl group in Example B12.
In Examples B1 to B6, urethane compounds having various side chains were produced using various diols B1 to B3 together with diol B4 derived from 3-acryloxypropyltrimethoxysilane, and an encapsulated pigment was produced from the urethane compound. And good results were obtained. When the polarity of the diol is increased, the solvent detachability is promoted, the back-through is reduced, and the wettability to the nozzle plate is also improved.

  In Examples B3 to B6, encapsulated pigments were prepared using urethane compounds having various side chains including a benzyl group together with side chains including a propyltrimethoxysilyl group, and wettability to the nozzle plate was further improved. It was done.

In Examples B7 and B8, units derived from 3-mercaptopropyltrimethoxysilane were introduced into an isocyanate group of a urethane compound, and encapsulated pigments were prepared using urethane compounds having various side chains including a benzyl group. And good results were obtained.
Example B9 produced a urethane compound having various side chains by using diol B5 derived from 3-glycidoxypropyltrimethoxysilane as compared with Example B3, and obtained good results.
In Example B10, a unit derived from 3-isocyanatopropyltriethoxysilane was introduced into the hydroxy group of the urethane compound to produce a urethane compound having various side chains, and good results were obtained. .
In Example B11, the composition of the solvent was changed with respect to Example B1, and good results were obtained.
In Example B12, a dihydric isocyanate was changed to prepare a urethane compound, and the constitution of the ink dispersant and the solvent was changed, and good results were obtained.
In Example B13, a urethane compound having a nitrogen-containing group together with a benzyl group was produced without introducing an alkoxysilyl group, and an encapsulated pigment was produced using this urethane compound, and good results were obtained.

  In Comparative Example B1, an encapsulated pigment was prepared using a urethane compound having a methoxypolyethylene glycol chain, and the urethane compound showed miscibility in a non-aqueous solvent, and the results of image see-through and image density of the printed matter were inferior. It was enough.

Claims (12)

An encapsulated pigment comprising a pigment and a urethane compound covering the surface of the pigment, and a non-aqueous solvent,
The urethane compound has a urethane skeleton and a side chain, and is a compound insoluble in the non-aqueous solvent,
The oil-based inkjet, wherein the side chain of the urethane compound includes at least one selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group ink.   The side chain of the urethane compound has an aromatic ring and at least one selected from the group consisting of a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group. The oil-based inkjet ink according to claim 1. The urethane compound has a structure in which units derived from polyisocyanate and units derived from alkanolamine are alternately arranged,
3. The oil-based inkjet ink according to claim 1, wherein a side chain of the urethane compound is bonded to the urethane compound through a nitrogen atom of a unit derived from the alkanolamine.   The oil-based inkjet ink according to claim 3, wherein the urethane compound further includes a unit derived from asymmetric glycol. The unit derived from the alkanolamine is:
A unit derived from dialkanolamine to which an acrylate having an aromatic ring is added by Michael,
Units derived from dialkanolamines with Michael addition of heterocyclic acrylamides,
The N-alkylamide contains one or more selected from the group consisting of a dialkanolamine-derived unit to which Michael is added, and a N, N-dialkylamide is a unit derived from a dialkanolamine to which Michael is added. The oil-based inkjet ink described in 1. The oil-based inkjet ink according to any one of claims 1 to 5, wherein the urethane compound has a repeating unit represented by the following formula (1).

(In Formula (1),
m, n and p are each independently a positive integer;
Y is an arbitrary divalent group,
R is -A-R ¹ , A is a single bond or any divalent group, R ¹ is an aromatic ring-containing group, a heterocyclic ring-containing group, a hydrogen atom, a carboxy group, an amide bond-containing group, 1 It is selected from a fluoroalkyl group having one or more fluorine atoms and a nitrile group, and these may have a substituent. )   The urethane compound has at least one side chain selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group, and an alkoxysilyl group. The oil-based inkjet ink of any one of Claim 1 to 6 containing these.   The oil-based inkjet ink according to claim 7, wherein the urethane compound includes a plurality of alkoxysilyl groups, and at least a part of the plurality of alkoxysilyl groups forms a siloxane bond. The urethane compound has a structure in which units derived from a polyisocyanate and units derived from a polyhydric alcohol are alternately arranged,
The unit derived from the polyhydric alcohol includes a unit derived from alkanolamine,
The unit derived from the alkanolamine is a compound having at least one selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group. The oil-based inkjet ink according to claim 7 or 8, comprising an added alkanolamine-derived unit A and an alkanolamine-derived unit B having an alkoxysilyl group.   The alkanolamine-derived unit B having an alkoxysilyl group is a alkanolamine-derived unit to which a compound having an alkoxysilyl group and an unsaturated double bond is Michael-added, and a compound having an alkoxy group and an epoxy group-containing group The oil-based inkjet ink of Claim 9 containing 1 or more types selected from the group which consists of the unit derived from the alkanolamine into which the alkoxy silyl group was introduce | transduced by reaction with. The urethane compound has a structure in which units derived from a polyisocyanate and units derived from a polyhydric alcohol are alternately arranged,
The unit derived from the polyhydric alcohol includes a unit derived from alkanolamine,
The unit derived from the alkanolamine is a compound having at least one selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group. Unit alkanolamine-derived unit A added,
The oil-based inkjet ink according to claim 7 or 8, wherein an alkoxysilyl group is introduced into an isocyanate group of the urethane compound via a mercapto group. The urethane compound has a structure in which units derived from a polyisocyanate and units derived from a polyhydric alcohol are alternately arranged,
The unit derived from the polyhydric alcohol includes a unit derived from alkanolamine,
The unit derived from the alkanolamine is a compound having at least one selected from the group consisting of an aromatic ring, a heterocyclic ring, a carboxy group, an amide bond, a fluoroalkyl group having one or more fluorine atoms, and a nitrile group. Unit alkanolamine-derived unit A added,
The oil-based inkjet ink according to claim 7 or 8, wherein an alkoxysilyl group is introduced into a hydroxy group of the urethane compound via an isocyanate group.