JP2007112963A - Water-based lithographic ink and printed product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a water-based lithographic ink capable of being cleaned with water after printing, improving the global environment and working environment, and having excellent high-speed printability and inking properties. <P>SOLUTION: The water-based lithographic ink contains a pigment, a water-soluble or dispersible resin, a hydroxy group-containing compound or an amino group-containing compound and water, and has ≥10 Pa s viscosity measured by a cone-plate type rotary viscometer at 25°C at 120 s<SP>-1</SP>shear rate. The water-soluble or dispersible resin (b) is one or more kinds of resins selected from an acrylic resin, a styrene-acrylic resin, a styrene-maleic acid resin and an α-olefin-maleic acid resin in the water-based lithographic ink. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a novel and useful aqueous lithographic printing ink and printed matter. More specifically, the present invention relates to a printing ink and printed matter that are suitably used for waterless lithographic printing.

  Lithographic printing is widely used as a system for supplying printed matter at high speed, in large quantities, and at low cost. Lithographic printing is a system in which dampening water is supplied to a non-image area, and an image area and a non-image area are formed using dampening water and ink repellency.

  In recent years, a waterless lithographic printing method has been proposed as a method for solving work related to dampening water and environmental problems, and in particular for the purpose of showing ink repellency in place of dampening water, A waterless printing method in which rubber is used for printing has been put into practical use.

  In general, lithographic inks are formed mainly of pigments, ink resins, petroleum solvents and vegetable oils. Petroleum solvents are also dearomatized from the viewpoint of global environmental protection and labor environment protection. In recent years, there has been a growing need for VOC-free inks that do not contain any volatile petroleum-based solvents that are more environmentally friendly. VOC is a compound that volatilizes at room temperature. The US Environmental Protection Agency presents the measurement of heating residue by heating at 110 ° C. for 1 hour as a VOC measurement method, which is used as a measurement method in accordance with actual use.

  As the VOC-free type ink, sheet-fed printing ink that forms a printed film by adding a metal dryer and oxidative polymerization has already been put into practical use, but printing is performed by evaporating the solvent in a hot air dryer. It has not yet been put to practical use in an off-wheel printing ink that forms a film.

Further, it is common to use a cleaning agent containing a volatile solvent as a cleaning agent for the lithographic ink after printing. It is desirable that the cleaning agent does not contain a volatile component from an environmental viewpoint. Patent Documents 1 to 4 disclose water-based lithographic printing using water-based water-based printing ink that uses water as a medium, and the water-based printing ink that is used is a flexographic ink or a similar structure, It is a physical property ink. However, the physical properties of flexographic inks are insufficient in high-speed printability and inking properties.
JP-A-7-232485 JP-A-8-310101 JP-A-8-169188 JP 2001-117218 A

  An object of the present invention is to solve the above-described problems and provide a water-based lithographic printing ink and printed matter that are excellent in high-speed printing suitability and inking property.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found an aqueous lithographic printing ink that is excellent in high-speed printing suitability and inking property and can be washed with water, and has completed the present invention.

That is, the present invention comprises (a) a pigment, (b) a water-soluble resin or a water-dispersible resin, (c) a hydroxyl group-containing compound or amino group-containing compound, and (d) water, and a cone plate type rotary viscometer The water-based lithographic printing ink is characterized in that the viscosity at 25 ° C. and the shear rate of 120 s ⁻¹ is 10 Pa · s or more.

  The present invention is also characterized in that (b) the water-soluble resin or the water-dispersible resin is at least one resin selected from an acrylic resin, a styrene acrylic resin, a styrene maleic acid resin, and an α-olefin maleic resin. The printing ink described above.

  Moreover, this invention is the printing ink of the said description whose heating volatile content in 110 degreeC 1 hour is 1% or less.

  Moreover, this invention is a printed matter formed by printing the said printing ink on a base material.

  The aqueous lithographic printing ink according to the present invention can provide excellent printability as a printing ink containing water as a medium and further containing no volatile solvent. After printing, it can be washed with water to improve the global environment and working environment.

  Hereinafter, the present invention will be specifically described. Examples of the pigment (a) used in the present invention include inorganic pigments and organic pigments. Inorganic pigments such as yellow lead, zinc yellow, bitumen, barium sulfate, cadmium red, titanium oxide, zinc white, petal, alumina white, calcium carbonate, ultramarine blue, carbon black, graphite, aluminum powder, etc. -Soluble azo pigments such as naphthol, β-oxynaphthoic acid, β-oxynaphthoic acid allylide, acetoacetate allylide, pyrazolone, β-naphthol, β-oxynaphthoic acid allylide, acetoacetyl allylide Insoluble azo pigments such as monoazo, acetoacetyl allyl disazo, pyrazolone, phthalocyanine pigments such as copper phthalocyanine blue, halogenated (chlorine or brominated) copper phthalocyanine blue, sulfonated copper phthalocyanine blue, metal-free phthalocyanine, quinacridone , Dioxazine, Polycyclic pigments such as pyrenetron, anthanthrone, indanthrone, anthrapyrimidine, flavantron, thioindigo, anthraquinone, perinone, perylene, etc., isoindolinone, metal complex, quinophthalone, and complex Various publicly known pigments such as cyclic pigments can be used.

  (B) Examples of water-soluble resins or water-dispersible resins include acrylic resins, styrene acrylic resins, styrene maleic resins, α-olefin maleic resins, polyester resins, polyurethane resins, epoxy resins, phenol resins, and the like. The resin is not particularly limited as long as the resin is water-dispersible or water-dispersible. Commercially available resins can also be suitably used. From the viewpoints of pigment dispersibility and ink storage stability, acrylic resins, styrene acrylic resins, styrene maleic resins, and α-olefin maleic resins are desirable.

  An acrylic resin is a resin obtained by addition polymerization of at least one monomer selected from acrylic acid, methacrylic acid, acrylic acid ester, and methacrylic acid ester. A comonomer containing a functional group such as a hydroxyl group, an epoxy group, or an amino group in the molecule can also be used. Furthermore, it is possible to partially copolymerize vinyl monomers such as vinyl acetate and vinyl chloride. In order to obtain a water-soluble or water-dispersible resin, it is necessary to neutralize with a basic compound after copolymerizing an acid group-containing monomer such as acrylic acid or methacrylic acid. The acid value is preferably 30 to 350 from the viewpoint of ink storage stability. It is also possible to make water-soluble or water-dispersed by copolymerization of a monomer containing a polyethylene oxide group in the molecule. The weight average molecular weight is preferably 5,000 to 100,000. Outside this range, it is not preferred because good ink storage stability and high-speed printing suitability are difficult to obtain.

  The styrene acrylic resin is a resin containing styrene as a monomer component in the acrylic resin. Similar to the acrylic resin, a comonomer containing a functional group such as a hydroxyl group, an epoxy group, or an amino group in the molecule can also be used. Furthermore, it is possible to partially copolymerize vinyl monomers such as vinyl acetate and vinyl chloride. In order to obtain a water-soluble or water-dispersible resin, it is necessary to neutralize part or all of the acid with a basic compound after copolymerizing an acid group-containing monomer such as acrylic acid or methacrylic acid. It is. The acid value is preferably 30 to 350 from the viewpoint of ink storage stability. It is also possible to make water-soluble or water-dispersed by copolymerization of a monomer containing a polyethylene oxide group in the molecule. The weight average molecular weight is preferably 5,000 to 100,000. Outside this range, it is not preferred because good ink storage stability and high-speed printing suitability are difficult to obtain.

  Styrene maleic acid resin is a resin obtained by copolymerizing styrene and maleic anhydride. Other monomers can also be partially copolymerized. Furthermore, it may be partially modified with a hydroxyl group-containing compound or an amino group-containing compound. A water-soluble or water-dispersible resin can be obtained by neutralizing part or all of the acid anhydride group or the modified acid group with a basic compound. The acid value is preferably 30 to 450 from the viewpoint of ink storage stability. The weight average molecular weight is preferably 5,000 to 100,000. Outside this range, it is not preferred because good ink storage stability and high-speed printing suitability are difficult to obtain.

  The α-olefin maleic acid resin is a resin obtained by copolymerizing an α-olefin and maleic anhydride. Other monomers can also be partially copolymerized. Furthermore, it may be partially modified with a hydroxyl group-containing compound or an amino group-containing compound. A water-soluble or water-dispersible resin can be obtained by neutralizing part or all of the acid anhydride group or the modified acid group with a basic compound. The acid value is preferably 30 to 450 from the viewpoint of ink storage stability. The weight average molecular weight is preferably 5,000 to 100,000. Outside this range, it is not preferred because good ink storage stability and high-speed printing suitability are difficult to obtain.

  Furthermore, the acrylic resin, styrene acrylic resin, styrene maleic acid resin, and α-olefin maleic resin can be obtained by emulsion polymerization in the presence of a surfactant.

  (C) The hydroxyl group-containing compound or amino group-containing compound is not particularly limited as long as it contains a hydroxyl group or an amino group in the molecule. Examples of the hydroxyl group-containing compound include ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, ethylene glycol, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol mono n -Propyl ether, ethylene glycol monoisopropyl ether, ethylene glycol mono n-butyl ether, ethylene glycol monoisobutyl ether, ethylene glycol monohexyl ether, ethylene glycol mono 2-ethylhexyl ether, ethylene glycol monoallyl ether, ethylene glycol monophenyl ether, ethylene Glycol monobenzyl ether, diethylene glycol, diethylene glycol Methyl ether, diethylene glycol monoethyl ether, diethylene glycol mono n-propyl ether, diethylene glycol monoisopropyl ether, diethylene glycol mono n-butyl ether, diethylene glycol monoisobutyl ether, diethylene glycol monohexyl ether, diethylene glycol mono 2-ethylhexyl ether, diethylene glycol monobenzyl ether, triethylene Glycol, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol mono n-butyl ether, tetraethylene glycol, tetraethylene glycol monomethyl, tetraethylene glycol monoethyl, tetraethylene glycol mono n-butyl, pro Len glycol, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono n-propyl ether, propylene glycol monoisopropyl ether, propylene glycol mono n-butyl ether, propylene glycol monophenyl ether, dipropylene glycol, dipropylene glycol monomethyl ether , Dipropylene glycol monoethyl ether, dipropylene glycol mono n-propyl ether, dipropylene glycol mono n-butyl ether, tripropylene glycol, tripropylene glycol monomethyl ether, tripropylene glycol monoethyl ether, tripropylene glycol mono n-butyl ether, 1,3-butanediol, 1, 4-butanediol, 3-methyl-1,3-butanediol, 2-methyl-2,4-pentanediol, 3-methyl-1,5-pentanediol, 3-methoxy-3-methyl-1-butanol, 2 -Ethyl-1,3-hexanediol, 2,4-diethyl-1,5-pentanediol, glycerin, diglycerin, acetylenic diol, diacetone alcohol and the like.

  Examples of amino group-containing compounds include monoethanolamine, N-methylmonoethanolamine, N, N-dimethylmonoethanolamine, N, N-diethylmonoethanolamine, 2- (2-aminoethoxy) ethanol, 2- (2 -Aminoethylamino) ethanol, 2-amino-1-butanol, 4-amino-1-butanol, diethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, triethanolamine, N- (3-aminopropyl) diethanolamine and the like. Can be mentioned.

Next, the usage form as printing ink in this invention is demonstrated. The printing ink in the present invention is usually used in the form of a lithographic printing ink, for example, sheet-fed ink, heat-set rotary ink, cold-set rotary ink, or the like. In general,
(A) Pigment 5-30% by weight
(B) Resin 10-40% by weight
(C) Hydroxyl group-containing compound or amino group-containing compound 5 to 40% by weight
(D) 10 to 50% by weight of water
(E) Other solvents 0 to 40% by weight
(F) Other additives 0 to 40% by weight
Is used in the composition consisting of

  When used as a VOC (volatile organic compound) free type ink, the VOC component may be 0% by weight in the above composition. VOC is an organic compound that volatilizes at room temperature. The US Environmental Protection Agency presents the measurement of heating residue by heating at 110 ° C. for 1 hour as a VOC measurement method, and is widely used as a measurement method in accordance with actual use. It is also applicable to the paper surface temperature in the off-wheel printer dryer, and is considered a reasonable judgment method.

  The resin is preferably used in the form of a resin varnish in which a basic compound is added and dissolved or dispersed in water as necessary for ease of handling.

  As other solvents, there can be used solvents used in general water-based inks and water-based paints other than the above-mentioned hydroxyl group-containing compound or amino group-containing compound.

  The printing ink of the present invention is a mixture of printing ink components such as pigments, resins or varnishes, kneaders such as kneaders, three rolls, attritors, sand mills, gate mixers, paint shakers, etc. Manufactured using a regulator.

As the viscosity of the printing ink, it is preferable that the viscosity at 25 ° C. and the shear rate of 120 s ⁻¹ measured by a cone plate type rotary viscometer is 10 Pa · s or more. Less than 10 Pa · s is not preferable because it tends to be insufficient in terms of high-speed printing suitability and inking properties.

  Furthermore, other additives can be used in the printing ink of the present invention as necessary. For example, anti-friction agent, anti-blocking agent, slip agent, anti-scratch agent include natural wax such as carnauba wax, wood wax, lanolin, montan wax, paraffin wax, microcrystalline wax, Fischer Trops wax, polyethylene wax, polypropylene Synthetic waxes such as wax, polytetrafluoroethylene wax, polyamide wax, and silicone compound can be exemplified.

[Example]
Next, the present invention will be described in detail with specific examples. In the examples, “parts” means parts by weight. The viscosity of the ink was measured at 25 ° C. and a shear rate of 120 s ⁻¹ with a cone plate rotational viscometer Roto Visco 1 manufactured by HAAKE.

(Resin production example 1)
200 parts of isopropyl alcohol was charged into a stirrer, a reflux condenser, and a flask equipped with a thermometer, heated to 90 ° C. while blowing nitrogen gas, and 90 parts of acrylic acid, 30 parts of 2-hydroxyethyl methacrylate, 180 parts of cyclohexyl methacrylate, 9 parts of perbutyl O (Nippon Yushi Co., Ltd. peroxide, t-butyl peroxy-2-ethylhexanoate) was added dropwise over 3 hours. After completion of dropping, the mixture was reacted at 90 ° C. for 2 hours, 1.5 parts of perbutyl O was added, and further reacted at 90 ° C. for 2 hours. After completion of the reaction, 76 parts of N-monoethanolamine and 481 parts of ion-exchanged water were added, isopropyl alcohol was distilled off, and the resin content was adjusted to 35% with ion-exchanged water to obtain a water-soluble resin (A1). Got.

(Resin production example 2)
In the same apparatus as in resin production example 1, 200 parts of isopropyl alcohol was charged and heated to 90 ° C. while blowing nitrogen gas, and 30 parts of acrylic acid, 60 parts of n-butyl acrylate, 210 parts of styrene, 9 parts of perbutyl O Was added dropwise over 3 hours. After completion of dropping, the mixture was reacted at 90 ° C. for 2 hours, 1.5 parts of perbutyl O was added, and further reacted at 90 ° C. for 2 hours. After completion of the reaction, 25 parts of N-monoethanolamine and 342 parts of ion-exchanged water were added, isopropyl alcohol was distilled off, and the resin content was adjusted to 45% with ion-exchanged water. )

(Resin production example 3)
200 parts of isopropyl alcohol was charged into the same apparatus as in resin production example 1, heated to 90 ° C. while blowing nitrogen gas, and 90 parts of maleic anhydride, 210 parts of styrene and 9 parts of perbutyl O were added over 3 hours. did. After completion of the addition, the mixture was reacted at 90 ° C. for 2 hours, 1.5 parts of perbutyl O was added, and further reacted at 90 ° C. for 2 hours. After completion of the reaction, 112 parts of N-monoethanolamine and 445 parts of ion-exchanged water were added, isopropyl alcohol was distilled off, and the resin content was adjusted to 35% with ion-exchanged water to obtain a water-soluble resin (A3). Got.

(Resin production example 4)
In an apparatus similar to that in Resin Production Example 1, 211 parts of diallen 168 (α-olefin manufactured by Mitsubishi Chemical Corporation) was charged, heated to 150 ° C. while blowing nitrogen gas, and 89 parts of maleic anhydride, perbutyl D ( 6 parts of peroxide manufactured by Nippon Oil & Fats Co., Ltd. and di-t-butyl peroxide) were added over 3 hours. After completion of the addition, the temperature was raised to 180 ° C. and reacted for 2 hours, 3 parts of perbutyl D was added, and further reacted at 180 ° C. for 2 hours. Further, 72 parts of diethylene glycol monoethyl was added and reacted at 180 ° C. for 6 hours. After completion of the reaction, 78 parts of N-monoethanolamine and 613 parts of ion-exchanged water were added to obtain a water-soluble resin (A4) having a resin content of 35%.

Example 1
20 parts of Lionol Blue FG7330 (manufactured by Toyo Ink Manufacturing Co., Ltd.), 55 parts of water-soluble resin (A1) obtained in Resin Production Example 1, 20 parts of diethylene glycol monoethyl, 4.9 parts of ion-exchanged water, and silicone defoaming A mixture of 0.1 part of the agent was kneaded with a red devil type paint conditioner for 30 minutes to prepare a printing ink having a viscosity of 24 Pa · s.

Examples 2-4, Comparative Example 1
Printing inks were prepared in the same manner as in Example 1 with the blending ratios shown in Table 1. The inks of Example 2 and Comparative Example 2 had a volatile content of 1% or less at 110 ° C. for 1 hour.

Sheet-fed printing test evaluation The inks of Examples 1 to 4 and Comparative Examples 1 to 2 were printed on a Mitsubishi Dia I-4 sheet-fed printing machine (Mitsubishi Heavy Industries, Ltd.) at 5,000 or 8,000 sheets / hour. Using SK coat 4/6 90 kg (manufactured by Nippon Paper Industries Co., Ltd.), plate surface temperature 27-30 ° C., printing plate HG-2 (manufactured by Toray Industries, Inc.), a printing test was performed on 5,000 sheets of each ink. The solid state and the soiled state were compared. The results are shown in Table 2.

Off-wheel printing test evaluation The inks of Examples 1 to 4 and Comparative Examples 1 and 2 were printed on a Mitsubishi BT2-800 NEO off-wheel printing machine (Mitsubishi Heavy Industries, Ltd.) at 300 or 500 rpm. A printing test of 10,000 sheets of each ink was performed as a printing plate TAP (manufactured by Nippon Paper Industries Co., Ltd.) and a printing plate TAP (manufactured by Toray Industries, Inc.), and the solid state of the printed matter and the state of the background stain were compared. The results are shown in Table 3.

The water-based lithographic printing ink according to the present invention can provide excellent printability as a printing ink containing water as a medium and not containing a volatile solvent. After printing, it can be washed with water to improve the global environment and working environment.

Claims (4)

(A) Pigment, (b) Water-soluble resin or water-dispersible resin, (c) Hydroxyl group-containing compound or amino group-containing compound, (d) Water, 25 ° C. measured by cone plate type rotary viscometer An aqueous lithographic printing ink having a viscosity at a shear rate of 120 s ⁻¹ of 10 Pa · s or more. (B) The water-soluble resin or the water-dispersible resin is at least one resin selected from an acrylic resin, a styrene acrylic resin, a styrene maleic resin, and an α-olefin maleic resin. Printing ink. The printing ink according to claim 1 or 2, wherein a heating volatile content at 110 ° C for 1 hour is 1% or less. A printed matter obtained by printing the printing ink according to any one of claims 1 to 3 on a substrate.