JP2017014306A - Aqueous ink composition for off-set printing without water, printing method using the aqueous ink composition and printed article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aqueous ink composition having almost no vaporization of organic compounds, excellent in water resistance of a printed article and suitable for off-set printing without water.SOLUTION: There is provided an aqueous ink composition for off-set printing without water by neutralizing an acid group of an acid group-containing acrylic resin obtained by polymerizing at least one kind of the formula (1) or (2) where R is H and B1 to 6 are each C1 to 12 alkyl without containing A and an acid group of an acid-containing rosin ester resin, with a basic compound.SELECTED DRAWING: None

Description

  The present invention relates to a water-based ink composition for waterless offset printing, a printing method using the water-based ink composition, and a printed material.

  Offset printing is widely used in the field of commercial printing because high-quality printed materials can be obtained efficiently. Since printing ink used for offset printing contains mineral oil, organic compounds derived from mineral oil volatilize during the printing process. In order to prevent the volatilized organic compound from being released into the atmosphere, it is necessary to install an afterburner to burn and remove the volatilized organic compound.

  In order to reduce volatilization of such organic compounds, it has been attempted to perform printing using water-based ink by waterless offset printing. As the water-based ink composition, there has been proposed a water-based ink composition containing a pigment, a water-soluble resin or a water-dispersible resin, a hydroxyl group-containing compound or an amino group-containing compound, and water as disclosed in Patent Documents 1-3. As the water-soluble resin or water-dispersible resin, one obtained by copolymerizing an acid group-containing monomer and then neutralizing part or all of the acid with a basic compound is used.

JP 2007-112963 A JP 2007-112964 A JP 2007-112965 A

  When such a water-based ink composition is used for high-speed printing, a step of drying water and other solvents in the printing ink using a dryer is provided. At this time, if a basic organic compound that volatilizes in the drying step is used, the water resistance of the ink coating is improved, but volatilization of the organic compound in the printing step (drying step) is inevitable. In order to prevent the volatilized organic compound from being released into the atmosphere, it is also necessary to perform treatment such as combustion removal.

  On the other hand, when a basic compound having a high boiling point that does not volatilize in the drying step is used, the basic compound stays in the ink coating film and the organic compound is hardly volatilized. Although it is not necessary to remove the combustion by installing an afterburner, the environmental load is reduced, but there is a problem that the water resistance of the printed matter is lowered due to the basic compound remaining in the ink coating film.

  The present invention has been made in order to solve at least a part of the above problems, and there is almost no volatilization of organic compounds in the printing process, the water resistance of the printed matter is excellent, and a water-based ink composition suitable for waterless offset printing, An object is to provide a printing method using the water-based ink composition and a printed material using the water-based ink composition.

(Application example 1)
An aqueous ink composition according to this application example includes a pigment, an acid group-containing acrylic resin, an acid group-containing rosin ester resin, a basic compound having a boiling point of 200 ° C. or more, and water, and includes an acid group-containing acrylic resin. Is obtained by polymerizing at least one of the monomers represented by the following formula (1) or (2), an acid group of the acid group-containing acrylic resin, an acid group of the acid group-containing rosin ester resin, Is neutralized with a basic compound.

（上記式（１）中、Ｒは水素、メチル基、エチル基のいずれかであり、Ａは炭素原子数が１以上１０以下のアルキル鎖、アルキレンエーテル、アルキルエステルのいずれかであり、Ｂ^１〜Ｂ^６はそれぞれ独立して、水素、炭素原子数が１以上１２以下のアルキル基、ヒドロキシル基、スルホン酸基、カルボキシル基のいずれかである。）

(In the above formula (1), R is any one of hydrogen, a methyl group, and an ethyl group, A is any one of an alkyl chain, alkylene ether, and alkyl ester having 1 to 10 carbon atoms, and B ¹ .about.B ⁶ are each independently hydrogen, 1 to 12 alkyl group carbon atoms, a hydroxyl group, a sulfonic acid group is either a carboxyl group.)

（上記式（２）中、Ｂ^７〜Ｂ^１２はそれぞれ独立して、水素、炭素原子数が１以上１２以下のアルキル基、ヒドロキシル基、スルホン酸基、カルボキシル基のいずれかである。）
このような水性インキ組成物は、印刷時における有機化合物の揮発が抑制されるとともに、耐水性に優れた印刷物を提供することができる。

(In the above formula (2), B ^{7 to} B ¹² are each independently hydrogen, an alkyl group having 1 to 12 carbon atoms, a hydroxyl group, a sulfonic acid group, or a carboxyl group.)
Such a water-based ink composition can provide a printed matter with excellent water resistance while suppressing volatilization of organic compounds during printing.

(Application example 2)
In the aqueous ink composition according to the above application example, the total content of the acid group-containing acrylic resin and the acid group-containing rosin ester resin is 5% by mass or more and 50% by mass or less of the total mass of the aqueous ink composition. The mass ratio of the acid group-containing acrylic resin and the acid group-containing rosin ester resin is preferably 10:90 or more and 90:10 or less.

(Application example 3)
In the water-based ink composition according to the application example described above, the monomer represented by the formula (1) or (2) is preferably at least one selected from dicyclopentenyloxyethyl methacrylate and dicyclopentenyloxyethyl acrylate.
(Application example 4)
In the water-based ink composition according to the application example, the acid group-containing acrylic resin is obtained by polymerizing a monomer mixture containing 5% by mass or more and 40% by mass or less of the monomer represented by the formula (1) or (2). It is preferable that

(Application example 5)
In the water-based ink composition according to the application example, the acid value of the acid group-containing acrylic resin is from 50 mgKOH / g to 200 mgKOH / g, and the acid value of the acid group-containing rosin ester resin is from 75 mgKOH / g to 300 mgKOH / g. Preferably there is.
(Application example 6)
The water-based ink composition according to the application example described above preferably further includes a hydrophilic organic solvent having a water solubility of 5% by mass to 80% by mass at 20 ° C.
(Application example 7)
The water-based ink composition according to the above application example preferably further includes a water-soluble organic solvent that dissolves in water at an arbitrary ratio at 20 ° C.

(Application example 8)
The printing method according to this application example uses the water-based ink composition according to the application example described above, and performs printing in a state where the relative humidity is maintained at 70% or more.
(Application example 9)
The printed matter according to this application example is printed using the water-based ink composition according to the application example.

  According to the water-based ink composition of the present invention, it is possible to provide a printed matter excellent in water resistance and printability while suppressing the volatilization of the organic compound in the printing process.

<Water-based ink composition>
The aqueous printing ink composition of the present invention includes a pigment, an acid group-containing acrylic resin, an acid group-containing rosin ester resin, a basic compound having a boiling point of 200 ° C. or higher, and water. Moreover, the water-based ink composition of the present invention does not substantially contain an organic compound that volatilizes in the drying step. In the present specification, “substantially free of organic compounds that volatilize in the drying step” means that the water-based ink composition is applied on a glass plate using an applicator 0.5 mil so that the ink film thickness becomes 12.5 μm. The case where the amount of the organic compound volatilized when applied and heated in a thermostat at 80 ° C. for 20 minutes to dry the ink coating film is less than 1% by mass of the applied aqueous ink composition. Hereinafter, the water-based printing ink composition of the present invention will be described in detail.

(Pigment)
The pigment used in the aqueous printing ink composition of the present invention is not particularly limited, and various inorganic pigments and organic pigments can be used.
As the inorganic pigment, barium sulfate, titanium oxide, zinc white, dial, alumina white, calcium carbonate, ultramarine, carbon black, graphite, aluminum powder and the like are used.

  Examples of organic pigments include soluble azo pigments (azo lake pigments), insoluble azo pigments, condensed azo pigments, copper phthalocyanine pigments, metal-free phthalocyanine pigments, condensed polycyclic pigments, and lake pigments of acidic or basic dyes.

  Examples of organic pigments include soluble azo pigments (azo lake pigments) such as acetoacetate anilide, pyrazolone, β-naphthol, β-oxynaphthoic acid, and β-oxynaphthoic acid anilide. Examples of the insoluble azo pigments include acetoacetanilide monoazo, acetoacetanilide disazo, pyrazolone monoazo, pyrazolone disazo, β-naphthol, β-oxynaphthoic acid anilide monoazo, and β-oxynaphthoic acid anilide disazo. Can be mentioned. Examples of the condensed azo pigment include acetoacetate anilide type and β-oxynaphthoic acid anilide type. Examples of the copper phthalocyanine pigment include copper phthalocyanine, halogenated copper phthalocyanine, and sulfonated copper phthalocyanine lake. Examples of the condensed polycyclic pigment include anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, and metal complex pigments.

(acrylic resin)
In this specification, an acrylic resin refers to a resin obtained by polymerizing a monomer mixture containing at least one (meth) acrylic acid or ester thereof. “(Meth) acrylic acid” refers to one or both of methacrylic acid and acrylic acid, and “(meth) acrylate” refers to one or both of methacrylate and acrylate.
The acrylic resin used in the water-based ink composition of the present invention must include at least one monomer represented by the following formula (1) or (2) and a monomer having an acidic group and a polymerizable group in one molecule. It is an acid group-containing acrylic resin which is obtained as a component and is copolymerized with other polymerizable monomers as required, and is neutralized with a basic compound having a boiling point of 200 ° C. or higher to make it water-soluble.

（上記式（１）中、Ｒは水素、メチル基、エチル基のいずれかであり、Ａは炭素原子数が１以上１０以下のアルキル鎖、アルキレンエーテル、アルキルエステルのいずれかであり、Ｂ^１〜Ｂ^６はそれぞれ独立して、水素、炭素原子数が１以上１２以下のアルキル基、ヒドロキシル基、スルホン酸基、カルボキシル基のいずれかである。）

(In the above formula (1), R is any one of hydrogen, a methyl group, and an ethyl group, A is any one of an alkyl chain, alkylene ether, and alkyl ester having 1 to 10 carbon atoms, and B ¹ .about.B ⁶ are each independently hydrogen, 1 to 12 alkyl group carbon atoms, a hydroxyl group, a sulfonic acid group is either a carboxyl group.)

（上記式（２）中、Ｂ^７〜Ｂ^１２はそれぞれ独立して、水素、炭素原子数が１以上１２以下のアルキル基、ヒドロキシル基、スルホン酸基、カルボキシル基のいずれかである。）

(In the above formula (2), B ^{7 to} B ¹² are each independently hydrogen, an alkyl group having 1 to 12 carbon atoms, a hydroxyl group, a sulfonic acid group, or a carboxyl group.)

  The acrylic resin synthesized containing such a monomer can be water-solubilized by neutralization with a basic compound to give the water-based printing ink composition a viscosity suitable for waterless offset printing. Moreover, the acrylic resin synthesized by including such a monomer can improve the water resistance of the ink coating film even when the basic compound used for neutralization remains. For the sake of simplicity, hereinafter, the monomer represented by the formula (1) or (2) is also referred to as a monomer (A).

  Examples of such a monomer (A) include dicyclopentenyloxyethyl methacrylate, dicyclopentenyloxyethyl acrylate, dicyclopentenyl acrylate, etc. Among them, dicyclopentenyloxyethyl methacrylate and dicyclopentenyloxyethyl acrylate are preferably used. It is done.

The acrylic resin used in the water-based ink composition of the present invention is obtained by copolymerizing a monomer having an acidic group and a polymerizable group in one molecule in addition to the monomer (A). For simplicity, a monomer having an acidic group and a polymerizable group in one molecule is also referred to as a monomer (B).
Examples of such a monomer (B) include ethylenically unsaturated monocarboxylic acids such as (meth) acrylic acid and crotonic acid, ethylenically unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid, maleic acid and itaconic acid. And acid anhydrides thereof and monoesterified products thereof, p-styrenesulfonic acid, p-styrenephosphoric acid, mono (meth) acryloyloxyethyl phosphate, and the like.

The acrylic resin used in the water-based ink composition of the present invention may be one obtained by copolymerizing a monomer mixture containing another polymerizable monomer in addition to the monomer (A) and the monomer (B). The other monomer is not particularly limited as long as it is a monomer copolymerizable with the monomer (A) and the monomer (B), and a known polymerizable monomer can be appropriately selected and used. For convenience, the monomer (A) and another monomer copolymerizable with the monomer (B) are also referred to as a monomer (C). As the monomer (C),
Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, n-butyl (meth) acrylate, i-butyl (meth) acrylate, t-butyl (meth) acrylate, hexyl (meth) acrylate, 2- Linear or branched aliphatic (meta) such as ethylhexyl (meth) acrylate, isononyl (meth) acrylate, isooctyl (meth) acrylate, n-octyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate ) Acrylate;
Cycloaliphatic (meth) acrylates such as cyclohexyl (meth) acrylate, trimethylcyclohexyl (meth) acrylate, isobornyl (meth) acrylate, bornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, adamantyl (meth) acrylate;
Aromatic (meth) acrylates such as benzyl (meth) acrylate;
Aromatic unsaturated monomers such as styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, t-butylstyrene, divinylbenzene, vinyltoluene;
Aliphatic unsaturated monomers such as ethylene, acetylene, butadiene;
Examples thereof include cycloaliphatic unsaturated monomers such as cyclopentene, cyclopentadiene and cyclohexene.

  The acrylic resin is a basic compound having a boiling point of 200 ° C. or more after copolymerizing a monomer mixture in which the monomer (A) and the monomer (B) are essential components and the monomer (C) is mixed as necessary. Used in combination.

  The proportion of the monomer (A) in such a monomer mixture is preferably 5% by mass to 40% by mass, more preferably 10% by mass to 35% by mass, and more preferably 15% by mass to 30%. More preferably, it is at most mass%. By making content of a monomer (A) into 5 mass% or more, the water resistance of the printed matter printed using the water-based ink composition of this invention can be made favorable. Moreover, when content of a monomer (A) exceeds 40 mass%, an acrylic resin will not become water-soluble and there exists a possibility that the printability of a water-based ink composition may fall.

  The acid value of the acrylic resin is preferably 50 mgKOH / g or more and 200 mgKOH / g or less, more preferably 75 mgKOH / g or more and 150 mgKOH / g or less, and further preferably 90 mgKOH / g or more and 125 mgKOH / g or less. . Such an acrylic resin can make the viscosity of the water-based ink composition suitable for waterless offset printing by neutralizing with a basic compound. The acid value of the acrylic resin is adjusted by the content of the monomer (B) in the monomer mixture.

The basic compound used for neutralizing the acrylic resin is not particularly limited as long as it has a boiling point of 200 ° C. or higher, and is diethanolamine, methyldiethanolamine, triethanolamine, diisopropanolamine, triisopropanolamine, N-ethyl. Diethanolamine, Nn-butyldiethanolamine, Nt-butyldiethanolamine, 4-amino-1-butanol, N- (β-aminoethyl) ethanolamine, N- (β-aminoethyl) isopropanolamine, cyclohexyldiethanolamine, Benzyldiethanolamine, 3- (2-ethylhexyloxy) propylamine, methoxypoly (oxyethylene / oxypropylene) -2-propylamine (for example, Jeffamine M manufactured by HUNTSMAN) Series), potassium hydroxide, sodium hydroxide, lithium hydroxide, calcium hydroxide, magnesium hydroxide, barium hydroxide, tetramethylammonium hydroxide, tetraethylammonium hydroxide, and the like.
Such a compound hardly volatilizes from the ink coating film even when the printed material is dried using a dryer or is naturally dried without using a dryer.

The weight average molecular weight of the acrylic resin is preferably 10,000 or more and 50,000 or less, more preferably 12,000 or more and 40,000 or less, and 15,000 or more and 35,000 or less. Further preferred.
The weight average molecular weight can be measured as a polystyrene converted value by a gel permeation chromatography method (GPC method). What is necessary is just to adjust polymerization temperature, polymerization time, the kind of polymerization initiator, the addition amount, the density | concentration of a monomer mixture, etc. so that the weight average molecular weight of an acrylic resin may become in said range.

(Rosin ester resin)
Examples of the rosin ester resin used in the water-based ink composition of the present invention include those obtained by esterifying rosins and polyhydric alcohols in the presence of an esterification catalyst. Moreover, the rosin ester resin used for the water-based ink composition of the present invention contains an acid group.
Examples of rosins include gum rosin, wood rosin, tall oil rosin, polymerized rosin, acid-modified rosin, and those purified by distillation or the like. Among them, it is preferable to use acid-modified rosin obtained by adding an unsaturated carboxylic acid or the like to rosins.

As a compound added to rosins to obtain an acid-modified rosin, an unsaturated carboxylic acid, an unsaturated dicarboxylic acid, a monoester thereof, or the like can be used. Specific examples of such compounds include fumaric acid, maleic acid, maleic anhydride, monomethyl maleic acid, monomethyl fumaric acid, monoethyl maleic acid, monoethyl fumaric acid, itaconic acid, itaconic anhydride, citraconic acid, citraconic anhydride. Acid, acrylic acid, methacrylic acid and the like can be mentioned, among which fumaric acid, maleic acid and maleic anhydride are preferably used.
The addition amount of unsaturated carboxylic acid or the like is preferably 1 molar equivalent or less with respect to 1 molar equivalent of rosin.

Examples of the polyhydric alcohol include glycerin, diglycerin, trimethylolethane, trimethylolpropane, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, sorbitol, and the like. Of these, glycerin, pentaerythritol and the like are preferably used.
The ratio of rosins and polyhydric alcohol used is appropriately adjusted according to the acid value of the target rosin ester resin.

  The acid value of the rosin ester resin is preferably 75 mgKOH / g or more and 300 mgKOH / g or less, more preferably 100 mgKOH / g or more and 250 mgKOH / g or less, and further preferably 125 mgKOH / g or more and 200 mgKOH / g or less. preferable. Such rosin ester resin can make the viscosity of the water-based ink composition suitable for waterless offset printing by neutralizing with a basic compound as will be described later. Furthermore, the dispersibility of the pigment in the water-based ink composition can be enhanced, and the inking property and gloss of the water-based ink composition can be improved.

  The rosin ester resin is used after being neutralized with a basic compound having a boiling point of 200 ° C. or higher and water-solubilized. The basic compound used for neutralization can be the same as that used for neutralization of the acrylic resin described above.

  The weight average molecular weight of the rosin ester resin used in the present invention is preferably 1,000 or more and 100,000 or less, more preferably 1,000 or more and 50,000 or less, and 5,000 or more and 20,000. More preferably, it is as follows. Such a rosin ester resin is excellent in pigment dispersibility, has good compatibility with the acrylic resin as described above, and provides the water-based ink composition of the present invention with printability suitable for waterless offset printing. Can do.

(solvent)
The water-based ink composition of the present invention uses water as a solvent. Tap water, ion exchange water, pure water or the like can be used, and there is no particular limitation.

Moreover, it is preferable to use together the water-soluble organic solvent whose boiling point is 200 degreeC or more. In this specification, the water-soluble organic solvent means a solvent that dissolves in water at 20 ° C. in an arbitrary ratio. Examples of such water-soluble organic solvents include diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,3- Butanediol, 3-methyl-1,5-pentanediol, 2-ethyl-1,3-hexanediol, 2,4-diethyl-1,5-pentanediol, glycerin, diglycerin, acetylenic diol, polyethylene glycol 200, polyethylene Examples include glycol 400 and polyethylene glycol 600.
By using such a water-soluble organic solvent in combination, it can be expected to improve the stability of the ink.

(Auxiliary)
The water-based ink composition of the present invention preferably contains a hydrophilic organic solvent having a water solubility at 20 ° C. of 5% by mass to 80% by mass and a boiling point of 200 ° C. or more as an auxiliary agent. As such a hydrophilic organic solvent, compounds as shown in the following formulas (3) to (6) are preferably used, and one or two or more of them can be used in combination.

（上記式（３）〜（６）中、Ｘ^ｔは炭素数３〜１８の飽和もしくは不飽和炭化水素基、フェニル基又はベンジル基であり、Ｙ^ｔは水素原子又はメチル基であり、Ｚ^ｔは水素原子又はメチル基であり、ｍ^ｕは０〜１５の整数であり、ｎ^ｖは０〜１５の整数であり、ｍ^ｕ＋ｎ^ｖは１以上である。また、上記式（３）〜（６）中、ｔ、ｕ及びｖは１以上４以下の任意の整数である。）

(In the formula (3) ~ (6), X t is a saturated or unsaturated hydrocarbon group, a phenyl group or a benzyl group having 3 to 18 carbon atoms, ^{Y t} is a hydrogen atom or a methyl group, ^{Z t} a hydrogen atom or a methyl group, ^{m u} is an integer of 0 to 15, ^{n v} is an integer of ^0~15, m u + ^{n v} is 1 or more. Further, the equation (3) - ( 6), t, u and v are any integers of 1 or more and 4 or less.)

  Specific examples of such hydrophilic organic solvents include those preferably used: ethylene glycol monohexyl ether, diethylene glycol monohexyl ether, ethylene glycol mono-2-ethylhexyl ether, diethylene glycol mono-2-ethylhexyl ether, ethylene Glycol monophenyl ether, diethylene glycol monophenyl ether, ethylene glycol monobenzyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monopropyl ether, tripropylene glycol monobutyl ether, propylene glycol monophenyl ether, diethylene glycol monolauryl ether, triethylene glycol mono Lauryl ether, tetraethyleneglycol Monolauryl ether, pentaethylene glycol monolauryl ether, tetraethylene glycol monomethyl oleyl ether and octaethylene glycol mono-oleyl ether and the like.

  Among these, diethylene glycol monohexyl ether, diethylene glycol mono-2-ethylhexyl ether, tripropylene glycol monobutyl ether, diethylene glycol monolauryl ether, triethylene glycol monolauryl ether, tetraethylene glycol monolauryl ether, and pentaethylene glycol monolauryl ether are particularly preferable. .

  A water-based ink composition containing such a hydrophilic organic solvent can improve the background stain resistance. This is because the hydrophilic organic solvent as described above is uniformly present in the water-based ink composition due to appropriate solubility in water, but does not completely dissolve, so it is detached from the water-based ink composition and the printing plate surface. This is thought to be because the release layer is formed at the interface between the water-based ink composition and the printing plate surface, and the ink hardly adheres to the non-image area.

  Moreover, since such a hydrophilic organic solvent is difficult to evaporate during printing, there is little fluctuation in the physical properties of the water-based ink composition, and the on-machine stability is improved. For this reason, it is possible to reduce the loss of the image line portion and the paper picking (edge pick).

  The content of such a hydrophilic organic solvent is preferably 1% by mass or more and 10% by mass or less, and more preferably 3% by mass or more and 7% by mass or less of the mass of the water-based ink composition. Thereby, the water-based ink composition excellent in soil stain resistance can be obtained.

(Other additives)
A surfactant may be added to the water-based ink composition used in the printing method of the present invention, if necessary. Cationic, anionic and nonionic surfactants can be used.

  In the water-based ink composition used in the printing method of the present invention, if necessary, one or more selected from the group consisting of vegetable oils, vegetable oil-derived fatty acid esters and ethers derived from vegetable oils may be used alone or arbitrarily in combination. Can be blended.

  Examples of vegetable oils include soybean oil, linseed oil, tung oil, castor oil, dehydrated castor oil, corn oil, safflower oil, south sea oil paulownia oil, regenerated vegetable oil, canol oil, and the like, and these thermal polymerization oils and oxidation polymerization oils. It is done.

  Vegetable oil-derived fatty acid esters include linseed oil fatty acid methyl ester, linseed oil fatty acid ethyl ester, linseed oil fatty acid propyl ester, linseed oil fatty acid butyl ester, soybean oil fatty acid methyl ester, soybean oil fatty acid ethyl ester, soybean oil fatty acid propyl ester, large Bean oil fatty acid butyl ester, palm oil fatty acid methyl ester, palm oil fatty acid ethyl ester, palm oil fatty acid propyl ester, palm oil fatty acid butyl ester, castor oil fatty acid methyl ester, castor oil fatty acid ethyl ester, castor oil fatty acid propyl ester, castor oil fatty acid butyl ester, regeneration An ester of vegetable oil, an ester of Nanyang oil tung oil, and the like are listed.

  Examples of ethers made from vegetable oils include di-n-octyl ether, di-nonyl ether, dihexyl ether, nonyl hexyl ether, nonyl butyl ether, diheptyl ether, didecyl ether, and nonyl octyl ether.

  The water-based ink composition of the present invention has printability suitable for waterless offset printing by including the water-soluble acrylic resin and the water-soluble rosin ester resin as described above. Furthermore, neutralizing the acid group-containing acrylic resin or acid group-containing rosin ester resin with a basic compound having a boiling point of 200 ° C. or higher makes these resins water-soluble and has a boiling point of 200 that volatilizes in the drying step. It is substantially free of organic compounds below ℃. For this reason, there is almost no volatilization of an organic compound through a printing process. When a basic compound having a boiling point of 200 ° C. or higher (that does not volatilize in the drying process) is used for neutralization of the acid group-containing acrylic resin or acid group-containing rosin ester resin, the ink coating is caused by the remaining basic compound. Although the water resistance of the film is lowered, the water-based ink composition of the present invention solves this by using one or more monomers represented by the above formula (1) or (2) as an essential component as an acrylic resin. did. That is, even when a high-boiling basic compound that remains in the ink coating is used for neutralization of the resin, it has excellent printability and good water resistance of the printed matter. it can.

  In order to obtain a water-based ink composition having a good balance between printability in waterless offset printing and water resistance of the ink coating film, the total content of acrylic resin and rosin ester resin is water-based ink. It is preferably 5% by mass or more and 50% by mass or less, more preferably 10% by mass or more and 40% by mass or less, and further preferably 15% by mass or more and 35% by mass or less of the total mass of the composition. The mass ratio of the acrylic resin and the rosin ester resin is preferably 10:90 or more and 90:10 or less, more preferably 20:80 or more and 80:20 or less, and 30:70 or more and 70:30 or less. More preferably it is. Thereby, it can be set as the water-based ink composition which has printability, the water resistance of printed matter, and the glossiness with good balance.

<Manufacturing method>
The water-based ink composition of the present invention is produced using a kneading disperser such as a roll mill after preparing a solution containing a water-soluble resin and then mixing the water-soluble resin solution and the pigment and other raw materials.

As a specific example, one or more monomers represented by the above formula (1) or (2) are essential components, and an acrylic resin is obtained by copolymerizing with other polymerizable monomers as necessary. A conventionally known method can be used as the polymerization method, and there is no particular limitation. When the solvent used for the polymerization includes a solvent that volatilizes in the drying step, it is removed by a method such as reduced pressure or solvent replacement. After neutralizing the obtained acrylic resin using a basic compound having a boiling point of 200 ° C., water, a water-soluble organic solvent or the like is added to obtain an acrylic resin solution.
In addition, rosin and polyhydric alcohol are esterified in the presence of an esterification catalyst to obtain a rosin ester resin. After neutralizing the obtained rosin ester resin with a basic compound having a boiling point of 200 ° C., water, a water-soluble organic solvent, etc. are added to obtain a rosin ester resin solution.

  After adding a pigment to the acrylic resin solution and rosin ester resin solution thus obtained and dispersing the mixture into a pigment base, the acrylic resin solution, rosin ester resin solution, water, other additives, A water-based ink composition is obtained by adding and adjusting the ink composition at an arbitrary ratio so as to have a desired viscosity.

<Printing method>
The water-based ink composition of the present invention can be suitably used for waterless offset printing. Since the removal rate of the solvent (water) from the ink coating film is high and it has an effect of rapid drying into the base material, it can be used not only for rotary printing but also for sheet-fed printing. Moreover, it is preferable to perform a printing process in the state maintained at 70% RH (relative humidity) or more, and it is more preferable to carry out in the state maintained at 80-100% RH. Thereby, the fluctuation | variation of the physical property of the printing ink composition in a printing process can be suppressed, and high quality printing can be performed stably.
In order to perform the printing process under the above conditions, the printing machine preferably includes a covering member and a humidifying member. The covering member may not completely seal the printing machine, and specific examples include a vinyl sheet and a plastic case. The humidifying member preferably includes at least a water supply unit, a humidifier, and a humidification sensor. As the humidifier provided in the humidifying member, one that humidifies without heating water is preferably used, and a vaporizing humidifier, an ultrasonic humidifier, and the like are exemplified. Among these, an ultrasonic humidifier is preferable.

<Printed matter>
The water-based ink composition of the present invention can be applied to various original fabrics used for offset printing. Volatilization of organic compounds in the printing process is suppressed, and the printed material has a small environmental load and is excellent in water resistance.

  Hereinafter, although an example and a comparative example explain the present invention, the present invention is not limited to this. In the following examples, parts and% are based on mass unless otherwise specified.

(Synthesis Example 1) Synthesis of acrylic resin solution A 164 parts of methyl ethyl ketone was placed in a reactor equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen blowing tube, and the temperature was raised to 80 ° C. Then, 200 parts of the monomer mixture shown in Table 1 and 20 parts of a solution in which perbutyl O (manufactured by NOF Corporation) and an equivalent amount of methyl ethyl ketone were mixed as radical polymerization initiators were dripped in parallel over 4 hours to complete the dropping. After stirring for 3 hours, 160 parts of purified glycerin (manufactured by Sakamoto Pharmaceutical Co., Ltd.) was added and stirred until uniform. Methyl ethyl ketone was distilled off under reduced pressure using a vacuum pump, and then 80 parts of triethanolamine was added to neutralize the acid groups of the acrylic resin. 200 parts of ion-exchanged water was added to make it water-soluble to obtain a water-soluble acrylic resin A solution. When the acid value was measured, it was 150 mgKOH / g.

Synthesis Example 2 Synthesis of Acrylic Resin Solution B A water-soluble acrylic resin B solution was obtained in the same manner as the acrylic resin solution A except that the monomer mixture was changed to that shown in Table 1.
Synthesis Example 3 Synthesis of Acrylic Resin Solution C A water-soluble acrylic resin C solution was obtained in the same manner as the acrylic resin solution A except that the monomer mixture was changed to that shown in Table 1.

(Synthesis Example 4) Synthesis of Acrylic Resin Solution D The monomer mixture was changed to the one shown in Table 1, and water-soluble acrylic was used in the same manner as the acrylic resin solution A except that dimethylethanolamine was used instead of triethanolamine. A solution of Resin D was obtained.
(Synthesis Example 5) Synthesis of Acrylic Resin Solution E The monomer mixture was changed to that shown in Table 1, and water-soluble acrylic was used in the same manner as Acrylic Resin Solution A except that dimethylethanolamine was used instead of triethanolamine. A solution of Resin E was obtained.

Synthesis Example 6 Synthesis of Acrylic Resin Solution F A water-soluble acrylic resin F solution was obtained in the same manner as the acrylic resin solution A except that the monomer mixture was changed to that shown in Table 1.
(Synthesis example 7) Synthesis | combination of acrylic resin solution G Except having changed the monomer mixture into what is shown in Table 1, it carried out similarly to water-soluble acrylic resin solution A, and obtained the solution of water-soluble acrylic resin G.

(Synthesis Example 8) Synthesis of acrylic resin dispersion H A water-dispersible acrylic resin H dispersion was obtained in the same manner as the water-soluble acrylic resin solution A except that the monomer mixture was changed to that shown in Table 1.
Synthesis Example 9 Synthesis of Acrylic Resin Solution I A water-soluble acrylic resin I solution was obtained in the same manner as the acrylic resin solution A except that the monomer mixture was changed to that shown in Table 1.

The acid values of the acrylic resin solutions (acrylic resin dispersions) B to I were also measured and summarized in Table 1.
In Table 1, St is styrene, MMA is methyl methacrylate, BA is butyl acrylate, AA is acrylic acid, and FA-512MT is dicyclopentenyloxyethyl methacrylate (Hitachi Chemical). FA-513M is dicyclopentanyl methacrylate (manufactured by Hitachi Chemical Co., Ltd.), CHMA is cyclohexyl methacrylate, DMEA is dimethylethanolamine, and TEA is triethanolamine. The unit is part by mass.

(Synthesis Example 11) Synthesis of water-soluble rosin ester resin solution A reactor equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blowing tube was charged with 1000 parts of gum rosin having an acid value of 165 mgKOH / g and 150 parts of fumaric acid. The temperature was raised to 200 ° C. 110 parts of pentaerythritol was added and reacted to obtain a rosin ester resin having an acid value of 152 mgKOH / g and a weight average molecular weight of 15,000.
In a reactor equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen blowing tube, 100 parts of the obtained rosin ester resin and 40 parts of triethanolamine were placed, and the temperature was raised to 140 ° C. After 30 parts of purified glycerin was added and completely dissolved, the temperature was lowered to 90 ° C., and 30 parts of ion-exchanged water was added to obtain a water-soluble rosin ester resin solution.

Example 1
40 parts of acrylic resin solution A, 25 parts of water-soluble rosin ester tree solution, and 17 parts of indigo pigment (FASTOGEN BLUE FDB15 manufactured by DIC Corporation) were kneaded with a three-roll disperser to prepare an indigo base. To this indigo base, 18 parts of ion-exchanged water was added to adjust the flow time at 25 ° C. and a load of 1000 g in a Raleigh viscometer (L-type viscometer) to be in the range of 18 seconds to 22 seconds. A water-based ink composition was obtained.

(Examples 2 and 3)
Aqueous ink compositions of Examples 2 and 3 were obtained in the same manner as in Example 1 except that the contents of the acrylic resin solution and the rosin ester resin solution were as shown in Table 2.
(Examples 4 and 5)
Aqueous ink compositions of Examples 4 and 5 were obtained in the same manner as in Example 1 except that the acrylic resin solution used was as shown in Table 2.
(Examples 6 to 8)
Examples 6 to 6 were carried out in the same manner as Example 1 except that BFTG (manufactured by Nippon Emulsifier Co., Ltd.) was added as a hydrophilic organic solvent having a boiling point of 200 ° C. or higher, and the amount of ion-exchanged water used was changed as shown in Table 3. 8 aqueous ink compositions were obtained.

(Comparative Examples 1-8)
The aqueous ink compositions of Comparative Examples 1 to 8 were prepared in the same manner as in Example 1 except that the acrylic resin solution used and the content thereof were as shown in Tables 3 and 4. However, the viscosity of the water-based ink composition of Comparative Example 7 using the water-dispersible acrylic resin dispersion H is 25 ° C. in a Raleigh viscometer (L-type viscometer), the flow time of 1000 g load is 18 seconds or less, The target viscosity was not achieved.

The aqueous ink compositions of Examples 1 to 10 and Comparative Examples 1 to 8 were evaluated by the following methods, and the results are summarized in Tables 2 to 4.
(Water resistance of paint film)
Apply the prepared ink to art paper using an applicator of 0.5 mil so that the ink film thickness is 12.5 μm, heat it using an IR dryer until the paper surface temperature reaches 80 ° C., and let it cool. A test piece was prepared. The ink coating of the test piece was rubbed with a cotton swab moistened with water, and the number of times until the coating of the rubbed part was removed was visually observed and evaluated in three stages.
3: The paint film cannot be removed even if the number of times of rubbing is 10 times or more. 2: The paint film can be taken if the number of times of rubbing is 6 times or more and 9 times or less. 1: The paint film can be taken if the number of times of rubbing is 5 times or less.

(Printability)
0.5 ml of ink is applied to an incometer manufactured by Toyo Seiki Co., Ltd., in which a waterless plate made by Presstec Co., Ltd., on which an image line has been formed, is attached to the upper rubber roll, and each rotation speed is 50 rpm, 75 rpm, and 100 rpm for 1 minute. It was rotated, and the degree of image formation on the plate was visually observed to evaluate waterless printing suitability in four stages. In addition, the roller temperature at the time of evaluation was 32 degreeC.
4: The image line is reproduced at a rotation speed of 50 rpm and the printability is excellent. 3: The image line is not reproduced at a rotation speed of 50 rpm, but is reproduced at 75 rpm. The printability is good. 2: The image line is reproduced at a rotation speed of 75 rpm. However, the printability that is reproduced at 100 rpm is a practical level. 1: The image line is not reproduced at a rotation speed of 100 rpm, or the image is not formed due to ink adhering to the non-image area.

(Glossy)
An applicator 0.5 mil was used to apply to an art paper so that the film thickness of the ink would be 12.5 μm, and after heating using an IR dryer, it was allowed to cool to prepare a test piece. The gloss of the test piece was measured using a BYK Gardner micro-TRI-gloss gloss meter (incident / reflection = 60 ° / 60 °) and evaluated in three stages by comparison with a conventional oil-based off-ring ink.
3: Higher gloss than conventional off-ring ink 2: Same gloss as conventional off-ring ink 1: Lower gloss than conventional off-ring ink

(Volatilization of organic compounds)
The amount of volatilization of organic compounds when the ink film is applied to a glass plate with an applicator of 0.5 mil so that the ink film thickness is 12.5 μm and heated in a thermostat at 80 ° C. for 20 minutes to dry the ink coating film. Was measured and evaluated in two stages.
2: The amount of the volatile organic compound is less than 1% by mass of the applied water-based ink composition 1: The amount of the volatile organic compound is 1% by mass or more of the applied aqueous ink composition

  As is clear from the examples and comparative examples, the water-based ink composition of the present invention has almost no volatilization of the organic compound and is excellent in water resistance, printability and gloss. The water-based ink composition of Comparative Example 7 using the acrylic resin dispersion H that was not water-soluble even when neutralized with a basic compound was not suitable for offset printing and could not be evaluated. It was.

Claims (9)

Pigments,
An acid group-containing acrylic resin;
An acid group-containing rosin ester resin;
A basic compound having a boiling point of 200 ° C. or higher;
Including water,
The acid group-containing acrylic resin is obtained by polymerizing at least one of the monomers represented by the following formula (1) or (2), and contains an acid group of the acid group-containing acrylic resin and an acid group A water-based ink composition for waterless offset printing, wherein an acid group of a rosin ester resin is neutralized with the basic compound.

(In the above formula (1), R is any one of hydrogen, a methyl group, and an ethyl group, A is any one of an alkyl chain, alkylene ether, and alkyl ester having 1 to 10 carbon atoms, and B ¹ .about.B ⁶ is hydrogen, 1 to 12 alkyl group carbon atoms, a hydroxyl group, a sulfonic acid group is either a carboxyl group.)

(In the above formula (2), B ^{7 to} B ¹² are any one of hydrogen, an alkyl group having 1 to 12 carbon atoms, a hydroxyl group, a sulfonic acid group, and a carboxyl group.)   The total content of the acid group-containing acrylic resin in the water-based ink composition and the content of the acid group-containing rosin ester resin is 5% by mass or more and 50% by mass or less of the total mass of the water-based ink composition. 2. The water-based ink composition according to claim 1, wherein the mass ratio of the acrylic resin and the acid group-containing rosin ester resin is 10:90 or more and 90:10 or less.   The water-based ink according to claim 1 or 2, wherein the monomer represented by the formula (1) or (2) is at least one selected from dicyclopentenyloxyethyl methacrylate and dicyclopentenyloxyethyl acrylate. Composition.   The acid group-containing acrylic resin is obtained by polymerizing a monomer mixture containing 5% by mass or more and 40% by mass or less of the monomer represented by the formula (1) or (2). Item 4. The water-based ink composition according to any one of Items 1 to 3.   The acid value of the acid group-containing acrylic resin is from 50 mgKOH / g to 200 mgKOH / g, and the acid value of the acid group-containing rosin ester resin is from 75 mgKOH / g to 300 mgKOH / g. The water-based ink composition as described in any one of thru | or 4.   The water-based ink composition according to any one of claims 1 to 5, further comprising a hydrophilic organic solvent having a water solubility of 5% by mass or more and 80% by mass or less at 20 ° C.   The water-based ink composition according to any one of claims 1 to 6, further comprising a water-soluble organic solvent that dissolves in water at 20 ° C at an arbitrary ratio.   A waterless offset printing method using the water-based ink composition according to any one of claims 1 to 7, wherein printing is performed in a state where the relative humidity is maintained at 70% or more.   Printed matter printed using the water-based ink composition according to any one of claims 1 to 7.