JPH1112528A - Pigment dispersion and ink composition using the same and used for offset printing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pigment dispersion containing a pigment well, finely and stably dispersed therein even in a high pigment concentration and further containing a general pigment dispersion auxiliary capable of being used also for white inks and light color inks. SOLUTION: This pigment dispersion comprises a pigment, a pigment dispersion auxiliary having aromatic rings and basic groups or acidic groups, a pigment dispersion resin having acidic or basic groups capable of forming salts groups together with the basic groups or acidic groups of the pigment dispersion auxiliary, a solvent, and, if necessary, a binder resin. Therein, the pigment dispersion auxiliary is a copolymer having an acidic value of 10-200 or an amine value of 10-200 and containing a monomer having an aromatic ring in an amount of 10-90 mol.%, and the pigment dispersion auxiliary and the pigment dispersion resin are contained in amounts of >=0.5 pt.wt. and >=0.5 pt.wt., respectively, per 100 pts.wt. of the pigment, wherein the total amount of the pigment dispersion auxiliary and the pigment dispersion resin is 1-51 pts.wt.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a technical field such as ink, paint or pigment-dispersed resist in which a pigment is finely dispersed at a high concentration in a non-aqueous medium and can be used for each color.
In particular, the present invention relates to a pigment dispersion useful for dispersing a pigment in the field of ink for offset printing, and an ink composition for offset printing using the same.

[0002]

2. Description of the Related Art In general, pigments are widely used in coating agents such as inks, paints or pigment-dispersed resists for the purpose of coloring, shielding light, preventing rust, and the like. These coatings include vivid colors, high gloss and tinting strength, high transparency, high fluidity required for handling, coating, printing, etc., and pigment reaggregation even after long-term storage. Stability is required. For this purpose, it is necessary to maintain good dispersibility even when the pigment concentration is increased.

[0003] However, even if the pigment is once finely dispersed in a meat mill, the finely dispersed pigment particles are likely to form a higher-order structure by reaggregation, and it is difficult to obtain a stable fine dispersion. Often, reduced color clarity, reduced tinting strength, reduced transparency, increased viscosity and increased yield value of a standing dispersion,
Phenomena such as a decrease in fluidity with an increase in temperature appear.

[0004] These phenomena not only deteriorate the quality of printed and coated materials, but also cause troubles in the printing and coating processes and in the manufacturing processes of inks, paints, pigment-dispersed resists and the like.

[0005] To improve these problems, various methods using a pigment dispersant have been carried out.

For example, US Pat. No. 3,996,05
No. 9, JP-A-61-163977 and the like,
A compound having a free amino group at a terminal synthesized by reacting a polyester obtained by dehydrating and condensing a hydroxycarboxylic acid with a specific amine has been proposed.

Further, US Pat. No. 4,224,212
Specification, U.S. Pat. No. 4,415,705, U.S. Pat. No. 3,882,088, etc., have a polyalkyleneimine having a molecular weight of 500 to tens of thousands directly with the above polyester, or Indirectly reacted products are described.

Further, JP-A-64-79279 discloses a
JP-A-2-99132 proposes a reaction product of a polyamine with a fatty acid or an acid anhydride.

However, these pigment dispersants have a certain effect in terms of increasing the concentration of the pigment in the non-aqueous dispersion system and stabilizing the dispersion, but still have an effect that can be satisfied with respect to the stabilization of the fine dispersion of the pigment. Was not obtained.

As represented by US Pat. No. 2,761,865 and Japanese Patent Publication No. 41-2466, a sulfon group, a sulfonamide group and an aminomethyl group are formed on the side chain of an organic pigment as a parent skeleton. And a method using a compound (pigment dispersion aid) obtained by introducing a substituent such as a phthalimidomethyl group.

According to this method, the effect of stabilizing the fine dispersion of the pigment is greater than that of the pigment dispersant,
It is known to be quite effective. However,
Since such a compound (pigment dispersing agent) uses an organic pigment as a base skeleton as described above, it can be used only for similar colors, and the pigment dispersing aid must be changed for each color. There is a problem that it cannot be used for white ink and light color ink.

[0012]

DISCLOSURE OF THE INVENTION The present invention has been made to solve these problems, and pigments can be finely dispersed and stabilized even at a high pigment concentration. To provide a pigment dispersion containing a versatile pigment dispersion aid that can also be used,
An object of the present invention is to provide an ink composition for offset printing using the same.

[0013]

Means for Solving the Problems The inventors of the present invention have conducted various studies to solve the above-mentioned problems. As a result, the following pigment dispersing aids having an aromatic ring and a basic group or an acid group, and The present inventors have found that these problems can be solved by using a pigment dispersing resin having an acid group or a basic group capable of forming a salt with a basic group or an acid group of the agent, and have completed the present invention. is there.

That is, the present invention provides: Pigment, a pigment dispersing aid having an aromatic ring and a basic group or an acid group, a pigment dispersing resin having an acid group or a basic group capable of forming a salt with the basic group or the acid group of the pigment dispersing aid, a solvent, A pigment dispersion containing a binder resin as required, wherein the pigment dispersing aid has an acid value of 10 to 90 mol% of a monomer having an aromatic ring in monomers constituting the copolymer. 10 to 200 or an amine number of 10 to 200, and a pigment dispersing aid of 0.5 parts by weight or more and a pigment dispersing resin of 0.5 parts by weight or more based on 100 parts by weight of the pigment. The present invention relates to a pigment dispersion, wherein the total amount of the dispersing aid and the pigment dispersing resin is 1 to 51 parts by weight.

Further, the present invention provides: 2. The pigment dispersion according to claim 1, wherein the pigment dispersion aid is at least one selected from the group consisting of the following (1) to (7).

(1) A copolymer obtained from a monomer having an aromatic ring, a monomer having an acid group, and if necessary, other copolymerizable monomers.

(2) An acid group and a monohydric alcohol of a copolymer obtained from a monomer having an aromatic ring, a monomer having an acid group, and if necessary, other copolymerizable monomers, A compound obtained by reacting a hydroxycarboxylic acid or a polycondensate thereof.

(3) A monomer having an aromatic ring, a monomer having a hydroxyl group, and if necessary, another copolymerizable monomer having no basic group are copolymerized. A compound having a carboxyl group obtained by reacting a hydroxyl group of a monomer having a hydroxyl group constituting a polymer with a compound having an acid anhydride ring.

(4) A monomer having an aromatic ring, a monomer having an epoxy group and, if necessary, other copolymerizable monomers having no reactivity with the epoxy group are copolymerized. Reacting a monocarboxylic acid or a hydroxycarboxylic acid or a polycondensate thereof with an epoxy group of a monomer having an epoxy group constituting a copolymer, and further, a compound having a hydroxyl group and an acid anhydride ring of the monomer A compound having a carboxyl group obtained by reacting

(5) A monomer having an aromatic ring, a compound having an unsaturated double bond and having an acid anhydride ring, and optionally a copolymer obtained from other copolymerizable monomers. A compound having a carboxyl group obtained by opening an acid anhydride ring.

(6) A copolymer obtained from a monomer having an aromatic ring, a monomer having a basic group, and if necessary, other copolymerizable monomers.

(7) A monomer having an aromatic ring, a monomer having an epoxy group, and if necessary, other copolymerizable monomers having no reactivity with the epoxy group are copolymerized. A compound having an amino group obtained by reacting an epoxy group of an epoxy group-containing monomer constituting a copolymer with an amine having at least one of a primary amino group and a secondary amino group.

Further, the present invention provides: 3. An ink composition for offset printing, comprising the pigment dispersion according to the above item 1 or 2.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION In the pigment dispersion of the present invention,
An acid capable of adsorbing or interacting with a pigment by a pigment dispersing aid (a copolymer having an aromatic ring and a basic group or an acid group) and forming a salt with the basic group or the acid group of the pigment dispersing aid. Interaction with a pigment dispersing resin having a basic group or a basic group suppresses the structural viscosity peculiar to a high-concentration fine dispersion of a pigment, and enables the handling, coating, and printing of inks, paints, pigment-dispersed resists, and the like. In addition, a high fluidity required at the time of production and a high stability without reagglomeration of the pigment for a long period of time are obtained. Further, since the pigment dispersing aid is not colored, it can be used for white ink and light-colored ink.

Hereinafter, the pigment of the present invention, a pigment dispersing aid (copolymer having an aromatic ring and a basic group or an acid group), a basic group or an acid group of the pigment dispersing aid and an acid group capable of forming a salt. Or a pigment-dispersing resin having a basic group (when the pigment dispersing aid is a copolymer having an acid group, a pigment-dispersing resin having a basic group is used in combination, and the pigment dispersing aid has a basic group. In the case of a copolymer, a pigment dispersion containing an acid group-containing pigment dispersing resin in combination, a solvent and, if necessary, a binder resin is used. In the monomers constituting the above, a monomer having an aromatic ring is 10 to 90
An acid value of 10 to 200 or an amine value of 10 to 20
The pigment dispersion containing the copolymer No. 0 and the ink composition for offset printing using the same will be described in detail.

As the pigment dispersing aid of the present invention, for example,
The following (1) to (7) can be exemplified.

<Pigment Dispersing Aid Used in Combination with Pigment Dispersing Resin Having Basic Group> (1) Monomer having aromatic ring, monomer having acid group, and other copolymerizable as required (Hereinafter, referred to as a pigment dispersing aid (1)).

(2) A monomer having an aromatic ring, a monomer having an acid group, and, if necessary, an acid group of a copolymer obtained from another copolymerizable monomer and a monohydric alcohol or A compound obtained by reacting hydroxycarboxylic acid or a polycondensate thereof (hereinafter referred to as a pigment dispersing aid (2)).

(3) A monomer having an aromatic ring, a monomer having a hydroxyl group, and if necessary, other copolymerizable monomers having no basic group are copolymerized. A compound having a carboxyl group obtained by reacting a hydroxyl group of a monomer having a hydroxyl group constituting a polymer with a compound having an acid anhydride ring (hereinafter, referred to as a pigment dispersing aid (3)).

(4) A monomer having an aromatic ring, a monomer having an epoxy group, and if necessary, another copolymerizable monomer having no reactivity with the epoxy group are copolymerized. Reacting a monocarboxylic acid or a hydroxycarboxylic acid or a polycondensate thereof with an epoxy group of a monomer having an epoxy group constituting a copolymer, and further, a compound having a hydroxyl group and an acid anhydride ring of the monomer (Hereinafter referred to as a pigment dispersing aid (4)).

(5) A monomer having an aromatic ring, a compound having an unsaturated double bond and having an acid anhydride ring, and optionally a copolymer obtained from other copolymerizable monomers. A compound having a carboxyl group obtained by opening an acid anhydride ring (hereinafter, referred to as a pigment dispersing aid (5)).

<Pigment Dispersing Aid Used in Combination with Pigment Dispersing Resin Having Acid Group> (6) A monomer having an aromatic ring, a monomer having a basic group, and other copolymerizable if necessary A copolymer obtained from a monomer (hereinafter, referred to as a pigment dispersing aid (6)).

(7) A monomer having an aromatic ring, a monomer having an epoxy group, and if necessary, another copolymerizable monomer having no reactivity with the epoxy group are copolymerized. A compound having an amino group obtained by reacting an epoxy group of an epoxy group-containing monomer constituting a copolymer with an amine having at least one of a primary amino group and a secondary amino group (hereinafter referred to as pigment dispersion Auxiliary (7)).

First, the pigment dispersing aid (copolymer having an aromatic ring and a basic group or an acid group) of the present invention will be described.

The pigment dispersing aid of the present invention can be obtained as follows.

The pigment dispersing aid (1) is composed of a monomer having an aromatic ring, a monomer having an acid group, and, if necessary, other copolymerizable monomers, and a peroxide or azo monomer. It can be obtained by reacting with a conventional method using a radical polymerization initiator such as a compound.

The pigment dispersing aid (2) is composed of a monomer having an aromatic ring, a monomer having an acid group and, if necessary, other copolymerizable monomers, and a peroxide or azo compound. After using a radical polymerization initiator such as a compound and reacting in a conventional manner to obtain a copolymer containing an acid group, a monohydric alcohol or hydroxycarboxylic acid described below is added to the acid group constituting the copolymer. Alternatively, it can be obtained by subjecting the polycondensate to a condensation reaction.

The pigment dispersing aid (3) comprises a monomer having an aromatic ring, a monomer having a hydroxyl group, and optionally another copolymerizable monomer having no basic group. Using a radical polymerization initiator such as a peroxide or an azo compound, and reacting in a conventional manner to obtain a hydroxyl group-containing copolymer,
It can be obtained by reacting a compound having an acid anhydride ring described below with a hydroxyl group of the copolymer.

The pigment dispersing aid (4) is a monomer having an aromatic ring, a monomer having an epoxy group, and if necessary, another copolymerizable monomer having no reactivity with the epoxy group. And a copolymer using a radical polymerization initiator such as a peroxide or an azo compound to obtain a copolymer containing an epoxy group by a conventional method, and then to the epoxy group of the copolymer, first, the following Or a polycondensate thereof, and then reacting a hydroxyl group of the monomer with a compound having an acid anhydride ring described below.

The pigment dispersing aid (5) is a monomer having an aromatic ring, a compound having an unsaturated double bond and having an acid anhydride ring, and optionally other copolymerizable monomers. And, using a radical polymerization initiator such as a peroxide or an azo compound, reacting in a conventional manner to obtain a copolymer having an acid anhydride ring, and then opening the acid anhydride ring of the copolymer. Can be obtained.

The pigment dispersing aid (6) is obtained by mixing a monomer having an aromatic ring, a monomer having a basic group, and if necessary, other copolymerizable monomers with a peroxide, It can be obtained by reacting by a conventional method using a radical polymerization initiator such as an azo compound.

The pigment dispersing aid (7) is a monomer having an aromatic ring, a monomer having an epoxy group, and if necessary, another copolymerizable monomer having no reactivity with the epoxy group. Is reacted with a radical polymerization initiator such as a peroxide or an azo compound by a conventional method to obtain a copolymer containing an epoxy group. And an amine having at least one kind of a secondary amino group and a secondary amino group.

In the case of the pigment dispersing aid (4) used in combination with the pigment dispersing resin having a basic group or the pigment dispersing aid (7) used in combination with the pigment dispersing resin having an acid group,
A monocarboxylic acid or hydroxycarboxylic acid described below or a polycondensate thereof, or a primary amino group,
Reaction of an amine having at least one kind of secondary amino group, and reaction of an epoxy group of an epoxy group-containing monomer with a monocarboxylic acid or hydroxycarboxylic acid described below or a polycondensate thereof to form an unsaturated double bond with a hydroxyl group formed. Reaction of a compound having an acid anhydride ring having no bond to obtain a monomer having a carboxyl group, or a reaction of a primary amino group and a secondary amino group described below to an epoxy group of an epoxy group-containing monomer. The reaction of reacting an amine having at least one kind to obtain a monomer having an amino group uses a solvent as necessary, and further includes an aliphatic amine, an aromatic amine,
Alternatively, using a catalyst such as an ammonium salt, a temperature of 60 to 160 ° C.
Heating.

Next, the pigment dispersing aid (1) of the present invention
(5) Materials for obtaining (in combination with a pigment dispersing resin having a basic group) and pigment dispersing aids (6) to (7) (when used in combination with a pigment dispersing resin having an acid group) Will be specifically described.

<1> Materials for Obtaining Pigment Dispersing Aid (1) or (6) As the monomer having an aromatic ring, styrene, vinyltoluene, α-methylstyrene, dimethylstyrene, ethylstyrene, isopropylstyrene , Alkyl-substituted styrene such as tert-butylstyrene, chlorostyrene, dichlorostyrene, bromostyrene, halogen-substituted styrene such as fluorostyrene, methoxystyrene, alkoxy-substituted styrene such as butoxystyrene, aryloxy-substituted styrene such as phenoxystyrene, β- Examples thereof include chlorostyrene, benzyl (meth) acrylate, and phenyl (meth) acrylate.

Examples of the monomer having a basic group or an acid group include polymerizable unsaturated carboxylic acids such as (meth) acrylic acid, itaconic acid, maleic acid, fumaric acid, crotonic acid and citraconic acid, and acid anhydrides thereof. Product, polycaprolactone acrylate, acryloyloxyethyl phthalate, a monomer having a carboxyl group such as acryloyloxysuccinate, a monomer having the carboxyl group is glycolic acid, lactic acid, oxyacid, hydroxyvaleric acid, hydroxycaproic acid, A monomer obtained by reacting a hydroxycarboxylic acid having 2 to 20 carbon atoms such as hydroxycaprylic acid, hydroxycapric acid, hydroxylauric acid, hydroxymyristic acid, hydroxypalmitic acid, 12-hydroxystearic acid or a polycondensate thereof, 2 -Hydroxyethyl (meth) acryl Over DOO, 2-hydroxypropyl (meth) acrylate, ethylene glycol mono (meth) acrylate, diethylene glycol mono (meth)
Acrylate, a monomer obtained by reacting a monomer having a hydroxyl group such as hydroxybutyl vinyl ether with a compound having an acid anhydride ring such as phthalic anhydride, succinic anhydride, glutaric anhydride, trimellitic anhydride, 2-dimethyl Monomers having a secondary or tertiary amino group such as aminoethyl (meth) acrylate and 2-ethylaminoethyl (meth) acrylate, glycidyl (meth) acrylate, 2,3-
Epoxy-2-methylpropyl (meth) acrylate,
A monomer having an epoxy group such as allyl glycidyl ether is reacted with a monovalent carboxylic acid such as acetic acid, propionic acid, butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, and stearic acid. The resulting hydroxyl group is reacted with the above-mentioned compound having an acid anhydride ring having no unsaturated double bond, and the above-mentioned monomer having an epoxy group is reacted with the above-mentioned hydroxycarboxylic acid or its polymer. A monomer obtained by reacting a compound having an acid anhydride ring having no unsaturated double bond with a hydroxyl group of a monomer obtained by reacting a condensate, a monomer having an epoxy group described above, Aliphatic 1 such as methylamine, ethylamine, propylamine, butylamine, amylamine, octylamine, dodecylamine, stearylamine, benzylamine, etc. Monoamines, aniline, aromatic primary monoamines such as naphthylamine, and their N
Amines having primary and / or secondary amino groups such as alkanol monoamines having primary or secondary amino groups such as secondary monoamines by monoalkyl substitution, ethanolamine, N-monoalkylethanolamine, diethanolamine, etc. Examples thereof include monomers having an amino group obtained by the reaction. In addition, as the compound having an acid anhydride ring, two acid anhydride rings may be used as long as the compound does not gel.
Compounds having more than one can also be used.

Other copolymerizable monomers used as required include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and cyclohexyl (meth) acrylate. , 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, dodecyl (meth) acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, behenyl (meth) acrylate, norbornyl (meth) acrylate (Meth) acrylates having cyclic ether groups such as tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate,
(Meth) acrylates having a hydroxyl group such as hydroxypropyl (meth) acrylate; vinyl ethers such as methyl vinyl ether, dodecyl vinyl ether and propenyl ether propylene carbonate; vinyl ethers having a hydroxyl group such as hydroxybutyl vinyl ether; and various acids such as allyl acetate. Allyl esters and the like can be exemplified.

<2> Materials for Obtaining Pigment Dispersing Aid (2) As the monomer having an aromatic ring, the monomer having an acid group, and other copolymerizable monomers as required, The same materials as those for obtaining the above-mentioned pigment dispersing aid (1) or (6) can be exemplified. Examples of the monohydric alcohol to be reacted with the acid group of the copolymer include methyl alcohol, butyl alcohol, pentyl alcohol, cyclohexanol, octyl alcohol, decyl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol and the like. Examples of the hydroxycarboxylic acid or the polycondensate thereof to be reacted with the acid group of the copolymer include the same materials as those described above for obtaining the pigment dispersing aid (1).

<3> Materials for Obtaining Pigment Dispersing Aid (3) As the monomer having an aromatic ring and the compound having an acid anhydride ring, the above-mentioned pigment dispersing aid (1) or (6) is used. The same materials as those for obtaining can be exemplified.

As the monomer having a hydroxyl group, the same materials as those for obtaining the above-mentioned pigment dispersing aid (1) or (6) may be used.
Examples thereof include (meth) acrylates having a hydroxyl group and vinyl ethers having a hydroxyl group.

As other copolymerizable monomers having no basic group, the same materials as those for obtaining the above-mentioned pigment dispersing aid (1) or (6) may be used. Alkyl esters, having a cyclic ether group (meth)
Examples thereof include acrylates, vinyl ethers, and allyl esters of various acids.

<4> Materials for Obtaining Pigment Dispersing Aid (4) Monomer having aromatic ring, monomer having epoxy group, monocarboxylic acid, hydroxycarboxylic acid or polycondensate thereof, acid anhydride Examples of the compound having a ring include the same compounds as those described above for obtaining the pigment dispersing aid (1) or (6).

Other copolymerizable monomers having no reactivity with the epoxy group include the same (meth) acrylic acid as the material for obtaining the above-mentioned pigment dispersing aid (1) or (6). Examples thereof include alkyl esters, (meth) acrylates having a cyclic ether group, (meth) acrylates having an aliphatic hydroxyl group, vinyl ethers, vinyl ethers having an aliphatic hydroxyl group, and allyl esters of various acids.

<5> Materials for Obtaining Pigment Dispersing Aid (5) The monomer having an aromatic ring and other copolymerizable monomers include the pigment dispersing aid (1) or (6) described above. ) Can be exemplified.

Compounds having an unsaturated double bond and having an acid anhydride ring include maleic anhydride, citraconic anhydride,
Examples thereof include itaconic anhydride, tetrahydrophthalic anhydride, and glutaconic anhydride.

Examples of the compound that opens the acid anhydride of the copolymer include water, methyl alcohol, ethyl alcohol, propyl alcohol, butyl alcohol, pentyl alcohol, cyclohexanol and benzyl alcohol.
Divalent alcohol, the above-mentioned pigment dispersing aid (1) or (6)
The same hydroxycarboxylic acids or polycondensates thereof as the material for obtaining the same can be exemplified.

<6> Materials for Obtaining Pigment Dispersing Aid (7) Monomers having an aromatic ring, monomers having an epoxy group,
Examples of the amine having at least one of a secondary amino group and a secondary amino group include the same materials as those described above for obtaining the pigment dispersing aid (1) or (6).

Examples of the other copolymerizable monomer having no reactivity with the epoxy group include the same as the above-mentioned materials for obtaining the pigment dispersing aid (4).

The pigment dispersing aid of the present invention must have an aromatic ring and a basic or acid group, preferably an aromatic ring and an amino or carboxyl group. for that purpose,
The compounds of the pigment dispersing aids (1) to (7) preferably contain 10 to 90 mol of a monomer having an aromatic ring in the copolymer.

When the pigment dispersing aid having a basic group or an acid group of the present invention is a basic group, the amine value is 10 to 20.
In the case of 0 and an acid group, the acid value is preferably from 10 to 200.

When both the aromatic ring and the basic group or the acid group (preferably the amino group or the carboxyl group) are not contained in a predetermined amount, sufficient pigment dispersibility cannot be obtained. However, appropriate values vary depending on the type of pigment, the specific surface area and particle size of the pigment particles, the properties of the pigment surface treatment agent, the polarity of the dispersion medium, and the like. There is a need.

When used in an ink composition for offset printing using a fountain solution, the amine value is 10 to 50 when the pigment dispersing aid is a basic group, and the acid group is an acid group. In this case, the acid value is preferably from 10 to 50.

The molecular weight of the pigment dispersing aid of the present invention is preferably in the range of 3,000 to 100,000 on a weight average. Even if the weight average molecular weight is less than 3,000, there is a pigment dispersing effect, but the polymerization reaction becomes difficult, and at the same time, the emulsification suitability tends to decrease due to the influence of terminal groups caused by a large amount of a polymerization initiator or a chain transfer agent. On the other hand, when the weight average molecular weight exceeds 100,000, there is a tendency that a sufficient pigment dispersing effect cannot be obtained.

Next, the pigment dispersing resin used in the present invention will be described.

The pigment dispersing resin used in the present invention is an pigment dispersing resin having an acid group or a basic group capable of forming a salt with a basic group or an acid group of the aforementioned pigment dispersing aid.

As the resin for dispersing a pigment having a basic group or an acid group, preferably, when the basic group is an amino group, the amine value is 10 to 200 (for an ink composition for offset printing using a fountain solution). When used, the acid value is preferably 10 to 50), and when the acid group is a carboxyl group, the acid value is 10 to 20.
0 (preferably 10 to 50 when used in an offset printing ink composition using a fountain solution) can be used. Specifically, a resin having an amino group is disclosed in Compounds obtained by reacting a polyester derived from a long-chain hydroxycarboxylic acid described in JP-A-271593 with a polyalkylenimine containing 3 to 6 nitrogen atoms, described in JP-A-61-234919. Reaction of a polyester derived from a long-chain hydroxycarboxylic acid with polyethylene glycol diamine, and reaction of biperazines with a polyester derived from a long-chain hydroxycarboxylic acid described in JP-A-61-163977. And compounds having a carboxyl group as disclosed in JP-A-9-25443. Publication, polyester compounds derived from long-chain hydroxycarboxylic acid as described in JP-A-9-25444 and the like.

Other than these, various alkyd resins,
Phenol resin, rosin ester resin, polyester resin, epoxy resin, urethane resin, acrylic resin, melamine resin, etc., or a modified product thereof and having a basic group or an acid group is used as a pigment dispersion resin. can do.

As the pigments to be used in the present invention, general achromatic or chromatic inorganic or organic pigments can be used.
Specifically, inorganic pigments such as titanium dioxide, barium sulfate, calcium carbonate, and magnetic iron oxide; colored pigments such as azo pigments, lake pigments, phthalocyanine pigments, isoindoline pigments, anthraquinone pigments, and quinacridone pigments; and carbon black. Is mentioned.

As the binder resin of the present invention that can be used as required, various known binders used in the fields of paints, pigment-dispersed resists, and ink compositions can be used.

In order to obtain a pigment dispersion containing the pigment, the pigment dispersing aid, the pigment dispersing resin, the solvent and, if necessary, the binder resin of the present invention, the pigment dispersing aid is added to 100 parts by weight of the pigment. 0.5 parts by weight or more, preferably 1 part by weight or more, and the pigment dispersing resin is 0.5 parts by weight or more, preferably 1 part by weight or more, and the total amount of the pigment dispersing aid and the pigment dispersing resin is 1 to It is preferable that the content is 51 parts by weight, preferably 2 to 35 parts by weight. If the amount of the pigment dispersing aid or the pigment dispersing resin is less than 0.5 parts by weight, a sufficient pigment dispersing effect cannot be obtained. Even if the total amount of the pigment dispersing aid and the pigment dispersing resin is more than 51 parts by weight, the pigment dispersing effect is not further improved.

When the pigment dispersion of the present invention is used in an offset printing ink composition, 0.5 parts by weight or more, preferably 1 part by weight or more of a pigment dispersing aid per 100 parts by weight of pigment. And 0.5 parts by weight or more, preferably 1 part by weight or more of the pigment dispersing resin, and the total amount of the pigment dispersing aid and the pigment dispersing resin is 1 to 51 parts by weight, preferably 2 parts by weight.
It is desirable to make it contained within the range of up to 35 parts by weight.
If the amount of the pigment dispersing aid or the pigment dispersing resin is less than 0.5 parts by weight, a sufficient pigment dispersing effect cannot be obtained. Also,
Even if the total amount of the pigment dispersing aid and the pigment dispersing resin is more than 51 parts by weight, the pigment dispersing effect is not further improved.

However, the pigment dispersing effect varies depending on the type of pigment, the specific surface area and particle size of the pigment particles, the properties of the pigment surface treating agent, the polarity of the dispersion medium, and the like. You need to determine the amount.

In producing an offset printing ink composition using the pigment dispersion of the present invention, a known binder resin, specifically, various alkyd resins, phenol resins, petroleum resins, rosin ester resins, polyester resins, etc. Alternatively, modified products thereof can be used, and as the solvent,
Linseed oil, tung oil, vegetable oils such as soybean oil, n-paraffin,
Mineral oils such as isoparaffin, aromatic solvent, and naphthene solvent can be used, and additives such as a dryer, a gelling agent, a drying retarder, and an antioxidant can be appropriately used.

The preferred ranges of each component in the offset printing ink composition of the present invention are shown below. Component Weight% Binder resin 20-50 Vegetable oil 0-60 Mineral oil 0-60 Pigment 2-60 Pigment dispersing aid 0.02-30 Resin for pigment dispersion 0.02-30

In the above composition, the ratio of the sum of vegetable oil and mineral oil is preferably 20 to 60% by weight.

In the above composition, the total amount of the pigment dispersing aid and the pigment dispersing resin is in the range of 1 to 51 parts by weight, more preferably 2 to 35 parts by weight, per 100 parts by weight of the pigment.
It is preferably in the range of parts by weight.

In the production of the ink base (pigment dispersion) for offset printing of the present invention, the pigment, the pigment dispersing aid, the pigment dispersing resin, the binder resin and the solvent are sufficiently stirred,
It can be prepared by milling with a bead mill, a three-roll mill or the like.

The production of the ink composition for offset printing of the present invention is carried out by adding an auxiliary agent such as a binder resin, a solvent and a wax to the above-mentioned ink base for offset printing, followed by mixing with a three-roll mill or the like. can do.

When the pigment composition of the present invention is used in applications other than the ink composition for offset printing of the present invention, such as paints and pigment-dispersed resists, various binders conventionally used in those fields are used. It can be prepared using a resin, a solvent and an additive.

[0080]

The present invention will be described below with reference to examples. The present invention is not limited to these examples unless it departs from the gist and scope of application. In the following description, “parts” indicates parts by weight.

Pigment Dispersing Aid 1 In a separable flask equipped with a cooling pipe, a water separation pipe, a thermometer, and a nitrogen introducing pipe, 166.6 parts of styrene and 34.4 parts of methacrylic acid (the ratio of each component to the total amount of both). Were added in an amount of 80 mol% and 20 mol%, respectively), and copolymerized using azobisisobutyronitrile as an initiator. Next, 64.8 parts of stearyl alcohol and xylene 30 were added to the copolymer.
Parts and 0.1 part of tetra-n-butyl titanate,
While azeotropically distilling off water generated under a nitrogen stream,
The condensation reaction was performed at 160 ° C. Weight average molecular weight 440
A copolymer having 0 and an acid value of 32 and having a carboxyl group (Pigment Dispersing Aid 1) was obtained.

Pigment Dispersing Aid 2 Instead of styrene and methacrylic acid in Pigment Dispersing Aid 1, 166.6 parts of styrene and 52.1 parts of hydroxyethyl methacrylate (the ratio of each component to the total amount of both was 80 mol% , 20 mol%).
Next, this copolymer was reacted with 13 parts of succinic anhydride to obtain a copolymer having a carboxyl group having a weight average molecular weight of 4,500 and an acid value of 33 (Pigment Dispersing Aid 2).

Pigment Dispersing Aid 3 Instead of styrene and methacrylic acid in Pigment Dispersing Aid 1, 16.6 parts of styrene and 56.9 parts of glycidyl methacrylate (the ratio of each component to the total amount of both was 80 mol%, 20 mol%). Next, 108.0 parts of stearic acid was added to this copolymer, and the reaction was carried out until the residual amount of carboxyl groups by the acid value measurement became below the measurement limit. 20 parts of succinic anhydride was further reacted with the copolymer having a hydroxyl group generated by ring opening of the epoxy group to obtain a copolymer having a carboxyl group having a weight average molecular weight of 4,700 and an acid value of 31 (pigment dispersing aid 3). I got

Pigment Dispersing Aid 4 300 g of 12-hydroxystearic acid was placed in a separable flask equipped with a cooling pipe, a water separation pipe, a thermometer, and a nitrogen inlet pipe.
To 0 parts, 300 parts of xylene and 3 parts of tetra-n-butyl titanate were added, and a condensation reaction was performed at 160 to 170 ° C. while azeotropically distilling off water generated under a nitrogen stream. When the acid value reached a predetermined value, xylene was distilled off to obtain a light brown acid value of 85.
Was obtained.

Next, 264 parts of this polyester A was used in place of stearic acid in Pigment Dispersing Aid 3, and 30 parts of succinic anhydride were subsequently reacted to obtain a copolymer having a carboxyl group having a weight average molecular weight of 6000 and an acid value of 32. A coalescence (pigment dispersion aid 4) was obtained.

Pigment Dispersing Aid 5 By changing 30 parts of succinic anhydride in Pigment Dispersing Aid 4 to 50 parts, a weight average molecular weight of 6000 and an acid value of 5 were obtained.
Thus, a copolymer having a carboxyl group of 2 (Pigment Dispersing Aid 5) was obtained.

Pigment Dispersing Aid 6 By changing 30 parts of succinic anhydride in Pigment Dispersing Aid 4 to 80 parts, a weight average molecular weight of 6000 and an acid value of 8 were obtained.
Thus, a copolymer having a carboxyl group of No. 4 (pigment dispersing aid 6) was obtained.

Pigment Dispersing Aid 7 Copolymer of 166.6 parts of styrene and 56.9 parts of glycidyl methacrylate in Pigment Dispersing Aid 4 (the ratio of each component to the total amount of both was 80 mol% and 20 mol%, respectively) Instead of using a copolymer having the same copolymerization ratio and different molecular weight, a copolymer having a carboxyl group having a weight average molecular weight of 8000 and an acid value of 30 (Pigment Dispersing Aid 7) is finally obtained. Was.

Pigment Dispersing Aid 8 Instead of 166.6 parts of styrene and 56.9 parts of glycidyl methacrylate in Pigment Dispersing Aid 4, the ratio of each component to the total amount of both was 80 mol% and 20 mol%, respectively. After copolymerizing 166.4 parts of styrene and 113.7 parts of glycidyl methacrylate (the ratio of each component to the total amount of both is 67 mol% and 33 mol%, respectively)
264 parts of polyester A and 24 parts of acetic acid were reacted.
Then, 53 parts of succinic anhydride was reacted to obtain a copolymer having a carboxyl group having a weight average molecular weight of 6000 and an acid value of 35 (Pigment Dispersing Aid 8).

Pigment Dispersing Aid 9 Instead of 166.6 parts of styrene and 56.9 parts of glycidyl methacrylate in Pigment Dispersing Aid 4, the ratio of each component to the total amount of both was 80 mol% and 20 mol%, respectively. After copolymerizing 41.6 parts of styrene and 227.2 parts of glycidyl methacrylate (the ratio of each component to the total amount of both was 20 mol% and 80 mol%, respectively), 264 parts of polyester A and 72 parts of acetic acid were reacted. Next, a copolymer having a carboxyl group having a weight average molecular weight of 6000 and an acid value of 30 (pigment dispersing aid 9) was obtained by reacting 80 parts of succinic anhydride.

Pigment Dispersing Aid 10 Instead of 166.6 parts of styrene and 56.9 parts of glycidyl methacrylate in Pigment Dispersing Aid 4 (the ratio of each component to the total amount of both is 80 mol% and 20 mol%, respectively) After copolymerizing 188.8 parts of vinyl toluene and 56.8 parts of glycidyl methacrylate (the ratio of each component to the total amount of both was 80 mol% and 20 mol%, respectively), 264 parts of polyester A was reacted. Next, a copolymer having a carboxyl group having a weight average molecular weight of 6,200 and an acid value of 34 (Pigment Dispersing Aid 10) was obtained by reacting 30 parts of succinic anhydride.

Pigment Dispersing Aid 11 Instead of 166.6 parts of styrene and glycidyl methacrylate (the ratio of each component to the total amount of both is 80 mol% and 20 mol%, respectively), 118.6 of styrene in pigment dispersing aid 4 is used. Parts, glycidyl methacrylate
After copolymerizing 6 parts and 18 parts of methyl methacrylate (the ratio of each component to the total amount of the three is 57 mol%, 34 mol%, and 9 mol%, respectively), polyester A264
Were reacted with 16.8 parts of acetic acid. Next, 40 parts of succinic anhydride was reacted to give a weight average molecular weight of 580.
A copolymer having 0 and an acid value of 30 and having a carboxyl group (pigment dispersing aid 11) was obtained.

Pigment Dispersing Aid 12 Instead of styrene and methacrylic acid in Pigment Dispersing Aid 1, 166.6 parts of styrene and 39.2 of maleic anhydride were used.
Parts (the ratio of each component to the total amount of both is 80
Mol%, 20 mol%). Next, 108.0 parts of stearyl alcohol was added to the copolymer and reacted. A copolymer having a carboxyl group having a weight average molecular weight of 5,900 and an acid value of 35 (Pigment Dispersing Aid 12) was obtained.

Pigment dispersing aid 13 Instead of styrene and methacrylic acid in Pigment dispersing aid 1, 166.6 parts of styrene, 53.8 parts of 2-dimethylaminoethyl methacrylate, and 44.5 parts of hydroxyethyl methacrylate (three parts) Are 70 mol%, 15 mol%, and 15 mol%, respectively, with respect to the total amount of
Thus, a copolymer having 5 amino groups (pigment dispersing aid 13) was obtained.

Pigment Dispersing Aid 14 Similarly to Pigment Dispersing Aid 3, 166.6 parts of styrene and 25.2 parts of glycidyl methacrylate (the ratio of each component to the total amount of both was 90 mol% and 10 mol%, respectively). After polymerization, 46.2 parts of stearylamine was reacted to obtain a copolymer having a weight average molecular weight of 6000 and an amino group having an amine value of 38 (Pigment Dispersing Aid 14).

[Comparative Pigment Dispersing Aid] Pigment Dispersing Aid 15 Instead of styrene and methacrylic acid in Pigment Dispersing Aid 1, only styrene was copolymerized to obtain a weight average molecular weight of 600.
Thus, a copolymer having no carboxyl group or amino group (Pigment Dispersing Aid 15) was obtained.

Pigment Dispersing Aid 16 Polyester A used in the synthesis of Pigment Dispersing Aid 4 was used as Pigment Dispersing Aid 16.

Pigment Dispersing Aid 17 A commercially available pigment dispersing aid (a phthalocyanine derivative having an acidic functional group) was used as the pigment dispersing aid 17.

[Pigment Dispersion Resin Having Basic or Acid Group Used in Combination with Pigment Dispersing Aid] Pigment Dispersion Resin 1 (Pigment Dispersion Resin Having Carboxyl Group) Cooling Tube, Water Separation Tube, Thermometer, Nitrogen Place 12-hydroxystearic acid 100 in a separable flask equipped with an inlet tube.
, A mixture of 10 parts of xylene and 0.1 part of tetra-n-butyl titanate was added, and the mixture was heated and stirred at 180 to 200 ° C. for 7 hours while separating water generated in a nitrogen stream into a water separation tube. Then, xylene was distilled off under reduced pressure, and a polyester resin having a carboxyl group, which was a light brown polymer having a weight average molecular weight of 4,000 and an acid value of 30 (resin for pigment dispersion 1)
I got

Resin for Pigment Dispersion 2 (Resin for Pigment Dispersion Having Amino Group) Resin having an amino group (poly-12-hydroxystearic acid having an amino group introduced into a terminal, weight average molecular weight 4,500, amine value) 25) was used as pigment dispersion resin 2.

[Ink Composition for Offset Printing] Examples 1 to 27 and Comparative Examples 1 to 13 Pigment dispersion aids 1 to 14, comparative pigment dispersion aids (pigment dispersion aids 15 to 17), and pigment dispersion Using the resins 1 and 2 and the amounts of the pigment dispersing aid and the pigment dispersing resin for the pigments shown in Tables 1 and 2, the ink bases for offset printing (indigo, black, red: base 1 , Yellow: base 2) was prepared. As the pigment, indigo is copper phthalocyanine (manufactured by Dainichi Seika Kogyo Co., Ltd.), black is carbon black (manufactured by Mitsubishi Chemical Corporation), and yellow is disazo yellow (manufactured by Dainippon Ink and Chemicals, Inc.). ), Crimson is Carmin 6
B (manufactured by Dainippon Ink and Chemicals, Inc.) was used. No. 5 solvent manufactured by Nippon Oil Co., Ltd. was used as the solvent. As the resin varnish A, a rosin-modified phenol resin (Tespol 135, manufactured by Hitachi Chemical Co., Ltd.)
5) was heated and dissolved in a mixed solvent of linseed oil and No. 5 solvent (resin concentration 55% by weight). In the ink base 1, the amount of the resin varnish A was changed in accordance with the amounts of the pigment dispersing aid and the pigment dispersing resin, so that the total amount of the ink base was 100 parts.

Formulation of ink base Base 1 Base 2 Component part Pigment 40 20 Pigment dispersing aid 0.8 to 8 1 Pigment dispersing resin 2 to 8 2 Resin varnish A 50 to 38 72 Solvent 6 5

After thoroughly stirring the mixture, three
The mixture was kneaded to prepare an ink base for offset printing. Using this, an ink for offset printing was prepared with the following composition. Here, polyethylene wax compound manufactured by Shamrock Co., Ltd. was used as the wax, and No. 5 solvent manufactured by Nippon Oil Co., Ltd. was used as the solvent. As the resin varnish B, rosin-modified phenol resin (manufactured by Hitachi Chemical Co., Ltd., Tespol 130)
The compound (4) was heated and dissolved in a mixed solvent of linseed oil and No. 5 solvent (resin concentration: 55% by weight).

Ink prescription Component part Ink base for offset printing 40 Resin varnish B 50 Wax 5 Solvent 5

[Evaluation Test] The results of evaluation of the properties and performance of the obtained offset printing ink base and offset printing ink are shown in Table 1 for indigo ink, and Table 2 for black ink, yellow ink and red ink. Indicated. In Comparative Examples 5 and 6, pigment equivalents were replaced with pigment dispersing resins without using pigment dispersing aids. In Comparative Examples 7, 9, 11, and 13, pigment dispersing aids were used. And resin varnish A without using pigment dispersing resin.
Was evaluated for those replaced by.

(1) Viscosity Using a cone-plate type rotational viscometer (manufactured by Rheometrics), the ink base for offset printing was used at 25 ° C.
And the shear rate 10.0 (1 /
s) (Pa · s) was measured. The lower the viscosity, the better.

(2) Coloring Power A white ink base was added to each of the ink bases for offset printing to dilute the ink bases, and the ink bases (Comparative Examples 7, 9, 11, and 13) which did not use a pigment dispersing aid and a resin for pigment dispersion were used. The coloring power was determined from the relative amount of the white ink base which can provide the same coloring as 100%. The higher the value, the better.

(3) Storage stability The ink base for offset printing and the ink for offset printing were stored in a thermostat at 25 ° C. for one month, and were judged from the change in viscosity with respect to the viscosity at the time of preparation. A sample with little increase in viscosity was evaluated as 3, a sample with relatively small increase in viscosity was evaluated as 2, and a sample with significantly increased viscosity was evaluated as 1.

[0109]

[Table 1]

[0110]

[Table 2]

The copolymer of the present invention having an aromatic ring and having a basic group or an acid group (a pigment dispersing aid), and an acid capable of forming a salt with the basic group or an acid group of the pigment dispersing aid. By using a pigment dispersing resin having a basic group or a basic group for offset printing ink, the viscosity and yield value of the offset printing ink base (pigment dispersion) decrease in each color of indigo, black, yellow, and red, resulting in coloring. Power improved. In addition, storage stability was excellent, and improvement in pigment dispersibility was shown. In comparison, in Comparative Examples, the pigment dispersibility was insufficient, or even if sufficient pigment dispersibility was obtained, the pigment dispersing aid itself was colored. It can be seen that it does not have any versatility. As can be seen from comparison with the examples, no pigment dispersing effect obtained by the pigment dispersion of the present invention was able to be obtained using novolak resin having an epoxy group or polyester alone. In addition, even when the pigment dispersion of the present invention was used, the storage stability of the ink was excellent, and improvement in pigment dispersibility was shown.

[0112]

The pigment dispersion of the present invention has an aromatic ring,
In addition, by using a copolymer having a basic group or an acid group (a pigment dispersing aid), it can be used for white ink and light-colored ink.

Further, the copolymer (pigment dispersing agent) having an aromatic ring and a basic group or an acid group of the present invention can form a salt with the basic group or the acid group of the pigment dispersing agent. Pigment dispersion containing a pigment dispersing resin having an acidic group or a basic group,
In particular, by using this in an offset printing ink, high fluidity, high coloring power and good storage stability of an offset printing ink base in which a pigment is dispersed at a high concentration can be obtained. For offset printing inks,
Good storage stability is obtained. Thereby, the working efficiency can be greatly improved as compared with the conventional one.

Claims (3)

[Claims] 1. A pigment, a pigment dispersing aid having an aromatic ring and a basic group or an acid group, and a pigment dispersion having an acid group or a basic group capable of forming a salt with the basic group or the acid group of the pigment dispersing aid. Resin, a solvent, a pigment dispersion containing a binder resin if necessary, wherein the pigment dispersing aid is a monomer having an aromatic ring in the monomers constituting the copolymer, in an amount of 10 to 90 mol. % Of a copolymer having an acid value of 10 to 200 or an amine value of 10 to 200, and at least 0.5 part by weight of a pigment dispersing aid and 0.5 part by weight of a resin for dispersing a pigment with respect to 100 parts by weight of a pigment. A pigment dispersion characterized by being contained in an amount of not less than 1 part by weight and a total amount of the pigment dispersing aid and the pigment dispersing resin of 1 to 51 parts by weight. 2. The pigment dispersion according to claim 1, wherein the pigment dispersion aid is at least one selected from the group consisting of the following (1) to (7). (1) A copolymer obtained from a monomer having an aromatic ring, a monomer having an acid group, and if necessary, other copolymerizable monomers. (2) An acid group of a copolymer obtained from a monomer having an aromatic ring, a monomer having an acid group, and optionally another copolymerizable monomer, and a monohydric alcohol or hydroxycarboxylic acid Or a compound obtained by reacting the polycondensate. (3) a monomer having an aromatic ring, a monomer having a hydroxyl group,
If necessary, other copolymerizable monomers not having a basic group are copolymerized, and then the compound having a hydroxyl group of the monomer having a hydroxyl group constituting the copolymer and having an acid anhydride ring A compound having a carboxyl group obtained by reacting (4) A monomer having an aromatic ring, a monomer having an epoxy group, and, if necessary, other copolymerizable monomers having no reactivity with the epoxy group are copolymerized. A monocarboxylic acid or a hydroxycarboxylic acid or a polycondensate thereof is reacted with the epoxy group of the monomer having an epoxy group constituting the union, and further, the hydroxyl group of the monomer is reacted with a compound having an acid anhydride ring. Having a carboxyl group obtained by the above method. (5) An acid anhydride of a copolymer obtained from a monomer having an aromatic ring, a compound having an unsaturated double bond and having an acid anhydride ring, and if necessary, other copolymerizable monomers. A compound having a carboxyl group obtained by opening a ring. (6) A copolymer obtained from a monomer having an aromatic ring, a monomer having a basic group, and if necessary, other copolymerizable monomers. (7) A monomer having an aromatic ring, a monomer having an epoxy group, and if necessary, another copolymerizable monomer having no reactivity with the epoxy group are copolymerized. A compound having an amino group obtained by reacting an epoxy group of an epoxy group-containing monomer constituting an union with an amine having at least one of a primary amino group and a secondary amino group. 3. An ink composition for offset printing, comprising the pigment dispersion according to claim 1.