JP4923577B2 - Water-based lithographic printing ink and printed matter - Google Patents

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 organic component from the 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, inking properties, stain resistance, water resistance, and friction resistance.
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 an aqueous lithographic printing ink and printed matter that are excellent in high-speed printing suitability, inking property, and stain resistance.

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

That is, the present invention provides (a) a pigment, (b) one or more resins selected from acrylic resins, styrene acrylic resins, styrene maleic resins, and α-olefin maleic resins , (c) vegetable oils or vegetable oil-derived fatty acid esters. And (d) a water-based lithographic printing ink characterized by containing water ,
The acrylic resin has an acid value of 30 to 350 and a weight average molecular weight of 5,000 to 100,000.
And
Styrene acrylic resin has an acid value of 30 to 350 and a weight average molecular weight of 5000 to
100,000
And
Styrene maleic acid resin has an acid value of 30 to 450 and a weight molecular weight of 5000 to
100,000
And
The α-olefin maleic acid resin has an acid value of 30 to 450 and a weight average molecular weight of 5000 to
100,000
A water-based lithographic printing ink characterized in that

  The present invention also provides the printing ink, wherein (c) the vegetable oil or the vegetable oil-derived fatty acid ester is a vegetable oil or a vegetable oil-derived fatty acid ester having an iodine value of 130 or more.

  The present invention also provides (c) a printing ink characterized in that the vegetable oil or vegetable oil-derived fatty acid ester is a vegetable oil or vegetable oil-derived fatty acid ester containing 30% or more of a fatty acid having a conjugated double bond as its fatty acid group.

Moreover, this invention is the said printing ink whose heating organic compound volatile matter in 110 degreeC 1 hour is 1 weight % or less.

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

  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.

  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, acetoacetyl allylide, pyrazolone, β-naphthol, β-oxynaphthoic acid allylide, acetoacetyl allylide Insoluble azo pigments such as monoazo, allyl acetoacetate 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 viewpoint 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 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.

  Examples of vegetable oils include soybean oil, cottonseed oil, linseed oil, safflower oil, tung oil, tall oil, dehydrated castor oil, canola oil and the like. Moreover, as vegetable oil-derived fatty acid esters, fatty acids derived from the above-mentioned vegetable oils, that is, alkyl main chains having about 15 to 20 carbon atoms such as stearic acid, isostearic acid, hydroxystearic acid, oleic acid, linoleic acid, linolenic acid, and eleostearic acid. Examples thereof include alkyl esters having about 1 to 10 carbon atoms such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl and 2-ethylhexyl.

  Since these vegetable oils and vegetable oil-derived fatty acid esters are not compatible with the aqueous resin, they are considered to diffuse from the ink by contact with the plate surface. In other words, the WFBL model is considered to significantly improve the soil resistance. The vegetable oil or vegetable oil-derived fatty acid ester is preferably contained in the ink in an amount of 1 to 30% by weight. Below this range, the effect is hardly recognized, and when it is more than this range, it is difficult to obtain stability on the printing press.

  Furthermore, the vegetable oil and the vegetable oil-derived fatty acid ester to be used are preferably those classified as a dry oil having an iodine value of 130 or more. Dry oil is preferable because the unsaturated fatty acid group has a high rate of formation of a cured film by oxidative polymerization, and the film strength tends to increase. Therefore, the water resistance and friction resistance of the ink film can be improved. Examples of vegetable oils having an iodine value of 130 or more include linseed oil (170 to 204), safflower oil (130 to 150), tung oil (155 to 175), dehydrated castor oil (130 to 145), etc. Examples of vegetable oil-derived fatty acid esters include alkyl esters derived from these vegetable oils.

  Furthermore, it is most preferable that the vegetable oil and the fatty acid ester derived from the vegetable oil to be used contain 20% or more of linolenic acid, eleostearic acid or the like having a conjugated double bond as the fatty acid group. Such vegetable oils and vegetable oil-derived fatty acid esters are preferred because the cured film formation rate and film strength tend to be particularly high. Linseed oil (linolenic acid 20-65%), tung oil (eleostearic acid 80%), etc. can be exemplified as this vegetable oil (components in parentheses are quoted from the Chemical Dictionary), and vegetable oil-derived fatty acid esters are derived from these vegetable oils The alkyl ester of can be illustrated.

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) Vegetable oil or vegetable oil-derived fatty acid ester 1 to 30% by weight
(D) 10 to 50% by weight of water
(E) Solvent 0-40% 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 the solvent, a solvent used in general water-based inks and water-based paints can be used.

  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.

The surface tension of the printing ink at 25 ° C. is preferably 40 dyncm ⁻¹ or more. The viscosity is preferably 25 Pa, measured by a cone plate type rotary viscometer, and the viscosity at a shear rate of 120 s ⁻¹ is 10 Pa · s or more. Outside the above range, it 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 is charged into a stirrer, a reflux condenser, and a flask equipped with a thermometer, heated to 90 ° C. while blowing nitrogen gas, 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, 62 parts of triethanolamine and 342 parts of ion-exchanged water were added, isopropyl alcohol was distilled off, adjusted with ion-exchanged water so that the resin content was 45%, and water-dispersible resin (A2) was obtained. Obtained.

(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.), 45 parts of water-soluble resin (A1) obtained in Resin Production Example 1, 10 parts of soybean oil, 20 parts of diethylene glycol, 4.9 parts of ion-exchanged water and A mixture of 0.1 part of the silicone antifoaming agent was kneaded for 30 minutes with a red devil type paint conditioner to prepare a printing ink having a viscosity of 22 Pa · s.

Examples 2-7, Comparative Examples 1-2
Printing inks were prepared in the same manner as in Example 1 with the blending ratios shown in Table 1. Inks of Example 2 and Comparative Example 2 had a VOC component of 0% by weight.

Sheet-fed printing test evaluation The inks of Examples 1 to 7 and Comparative Examples 1 and 2 were SK coated at 5,000 sheets / hour on a Mitsubishi Diamond I-4 sheet-fed printing machine (Mitsubishi Heavy Industries, Ltd.). 4/6 90kg (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 of 5,000 sheets of each ink, solid state of printed matter , Soil dirt, water resistance, friction resistance state was compared. The fleshing condition and background stain were evaluated by visual observation of the printed matter, and the water resistance was visually evaluated after the surface of the printed material was rubbed three times with a wet cotton swab. Friction resistance was visually evaluated using a Toyo Seiki Gakushin type friction tester with a load of 100 g and 10 reciprocations using a white surface of art paper as the paper. The results are shown in Table 2.

Off-wheel printing test evaluation The inks of Examples 1 to 5 and Comparative Examples 1 and 2 were printed on a Mitsubishi BT2-800 NEO off-wheel printing machine (Mitsubishi Heavy Industries, Ltd.) at 300 rpm with NPI coated paper 66.5 kg (Japan) Papermaking Co., Ltd.) and printing plate TAP (manufactured by Toray Industries, Inc.) were subjected to a printing test on 10,000 sheets of each ink, and the solid state, ground stain, water resistance, and friction resistance of the printed materials were compared. . The fleshing condition and background stain were evaluated by visual observation of the printed material, and the water resistance was evaluated by visual relative evaluation of the surface of the printed material after rubbing three times with a wet cotton swab. Friction resistance was visually evaluated using a Toyo Seiki Gakushin type friction tester with a load of 100 g and 10 reciprocations using a white surface of art paper as the paper. 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 (5)

(A) a pigment, (b) one or more resins selected from acrylic resins, styrene acrylic resins, styrene maleic resins, α-olefin maleic resins , (c) vegetable oils or vegetable oil-derived fatty acid esters, and (d) water. A water-based lithographic printing ink characterized by containing ,
The acrylic resin has an acid value of 30 to 350 and a weight average molecular weight of 5,000 to 100,000.
And
Styrene acrylic resin has an acid value of 30 to 350 and a weight average molecular weight of 5000 to
100,000
And
Styrene maleic acid resin has an acid value of 30 to 450 and a weight molecular weight of 5000 to
100,000
And
The α-olefin maleic acid resin has an acid value of 30 to 450 and a weight average molecular weight of 5000 to
100,000
A water-based lithographic printing ink characterized by (C) vegetable oil or vegetable oil-derived fatty acid ester, according to claim 1 Symbol placement of the printing ink, characterized in that a iodine value 130 or more vegetable oils or vegetable oil-derived fatty acid ester. (C) a vegetable oil or vegetable oil-derived fatty acid ester is its fatty acid groups, according to claim 1 or 2 Symbol mounting of the printing ink, characterized in that the fatty acids with conjugated double bonds is a vegetable oil or vegetable oil-derived fatty acid esters containing at least 20% . The printing ink according to any one of claims 1 to 3 , wherein the volatile content of the organic compound by heating at 110 ° C for 1 hour is 1% by weight or less. A printed matter obtained by printing the printing ink according to any one of claims 1 to 4 on a substrate.