JP6391859B2 - Binder for water-based liquid ink, water-based liquid ink and printed matter - Google Patents

Description

  The present invention relates to a resin binder for aqueous liquid ink that can be used for aqueous gravure printing and aqueous flexographic printing, and an aqueous liquid ink composition.

Water-based gravure printing and water-based flexographic printing are widely used for the purpose of imparting cosmetic properties and functionality to a printing medium.
In recent years, in the printing ink industry, occupational safety and health, and flammable explosive properties have been built on the basis of sustainability against the background of global expansion such as worsening air pollution caused by VOCs contained in solvent-based printing inks and global warming. In addition, there is a move to shift to oil-free resources, and regulations on the use of organic solvents are becoming stricter.

On the other hand, film packaging consumption has been increasing globally due to population growth, income level rise, and changes in the distribution system, and the production of packaging ink has been increasing year by year.
In the past, solvent-type flexographic inks and solvent-type gravure inks have been mainly used for film package printing. However, due to the changes in environmental consciousness shown above, water-based organic solvents have recently been replaced with water. Ink is being developed, and the development and improvement of higher quality water-based liquid ink is being started.

  However, compared with solvent-type liquid inks, water-based liquid inks are designed to reduce the adhesion to the film, the blocking resistance associated with the print pattern back-off, and the entanglement stains caused by drying of the ink on the plate during long run printing. In terms of `` re-solubility of water, '' there is a need for further improvement in performance, and without this, sufficient recognition is not obtained, and more rapid spread is not expected. .

  As an example of a surface-printing water-based ink composition for packaging, an organic solvent solution of a polyretane resin obtained by reacting a polyhydrazide compound and a polyamine compound other than the polyhydrazide compound with an isocyanate group-containing polymer, deionized water containing aqueous ammonia Although the invention has been made using an aqueous polyurethane resin that has been water-solubilized by neutralization with a binder, it can be said that the re-solubility is sufficient even if adhesion to the film and blocking resistance can be maintained. In particular, it cannot be said that it can withstand long-run printing (for example, Patent Document 1: Japanese Patent Laid-Open No. 8-053641).

  Also, a water-based printing ink composition for laminating using an aqueous polyurethane resin obtained by reacting an organic diisocyanate compound, a polymer diol compound containing a specific polycarbonate diol, and a chain extender, and then adding water and trimethylamine to make it water-based Although the invention of the product has been made, it cannot be said that the invention takes into account blocking resistance and re-dissolution (for example, Patent Document 2: JP-A-5-171091).

  Higher than the trade-off between improved anti-blocking and improved re-dissolvability, while maintaining adhesion to the base material, in order to spread the use of water-based liquid inks that can be selected in terms of the global environment, work environment, and cost. Development of high quality aqueous liquid ink binders is desired.

JP-A-8-053641 Japanese Patent Laid-Open No. 5-171091

  The problems to be solved by the present invention include a binder for an aqueous liquid ink that can be used for an aqueous liquid ink excellent in adhesion to a substrate, blocking resistance, and ink re-dissolvability, and an aqueous liquid ink composition containing the binder. Is to provide things.

  As a result of diligent research to solve the above-mentioned problems, the present inventors have used the aqueous liquid ink binder containing a urethane resin obtained by neutralizing an acid group of a urethane resin with a metal salt. The inventors have found that this can be solved and completed the present invention.

  That is, the present invention provides a polyol (a1) containing a polyol (a1-1) having an acid group and a polyether polyol (a1-2) other than the polyol (a1-1), and a polyisocyanate (a2). This is a binder for aqueous liquid ink containing the urethane resin (A) which is a reaction product of the above and an aqueous medium (B), wherein the acid group of the urethane resin (A) is neutralized with a metal salt. Yes, the urethane resin (A) contains an alicyclic structure in the range of 1000 to 5000 mmol / kg with respect to the entire urethane resin (A), and contains the binder for aqueous liquid ink and the binder The present invention relates to an aqueous liquid ink composition.

  Moreover, this invention relates to the binder for aqueous | water-based liquid inks whose acid value of the said urethane resin (A) is the range of 10-50.

  Moreover, this invention relates to the binder for aqueous | water-based liquid inks in which the said polyol (a1) contains 0-20 mass% of polyol (a1-3) which has an alicyclic structure further.

  The present invention also relates to an aqueous liquid ink comprising the aqueous liquid ink binder, pigment, and water, wherein the surface tension at 25 ° C. is 25 to 50 mN / m.

  The present invention also relates to a printed matter characterized in that flexographic printing is performed with the water-based liquid ink.

  The present invention also provides a printed matter characterized in that gravure printing is performed with the water-based liquid ink.

  If it is the binder for aqueous | water-based liquid inks of this invention, the aqueous | water-based liquid ink excellent in the adhesiveness with respect to a base material, blocking resistance, and the re-dissolution property of ink can be obtained.

  The binder for aqueous liquid ink of the present invention is characterized by containing a urethane resin (A) and an aqueous medium (B).

  Examples of the urethane resin (A) include a polyol (a1) containing an acid group-containing polyol (a1-1) and a polyether polyol (a1-2) other than the polyol (a1-1), and What was obtained by making it react with polyisocyanate (a2) can be used.

  Examples of the polyol (a1-1) having an acid group include a polyol having a carboxyl group and a polyol having a sulfonic acid group.

  Examples of the polyol having a carboxyl group include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolvaleric acid, and the like. Of these, 2,2-dimethylolpropionic acid and 2,2-dimethylolbutanoic acid, which have good dispersion stability, are preferred. Moreover, the polyester polyol which has a carboxyl group obtained by making the polyol which has the said carboxyl group react with various polycarboxylic acids can also be used. These polyols having a carboxyl group can be used alone or in combination of two or more.

  Examples of the polyol having a sulfonic acid group include dicarboxylic acids such as 5-sulfoisophthalic acid, sulfoterephthalic acid, 4-sulfophthalic acid, 5- (4-sulfophenoxy) isophthalic acid, and salts thereof, ethylene glycol, Examples thereof include polyester polyols obtained by reacting low molecular polyols such as propylene glycol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, and neopentyl glycol. These polyols having a sulfonic acid group can be used alone or in combination of two or more.

  The polyol (a1-1) having an acid group is preferably used in the range where the acid value of the urethane resin (A) is from 10 to 50, more preferably from 10 to 35. In addition, the acid value said by this invention is the theoretical value computed based on the usage-amount of acid group containing compounds, such as a polyol (a1-1) which has an acid group used for manufacture of the said urethane resin (A).

  In order to express good water dispersibility, part or all of the acid groups are neutralized by metal ions such as sodium, potassium, calcium, copper, and lithium to form a metal salt. preferable. As a neutralization rate, the range of 30 to 130% is preferable, and the range of 50 to 100% is more preferable.

  Metal ions such as sodium, potassium, calcium, copper, and lithium that can be used to neutralize the acid group include, for example, metal hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide, and chlorides. It can be obtained from metal chlorides such as sodium and potassium chloride and metal sulfides such as copper sulfate.

  Examples of the polyether polyol (a1-2) include those obtained by addition polymerization of alkylene oxide using one or more compounds having two or more active hydrogen atoms as an initiator.

  Examples of the initiator include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, bisphenol A, glycerin, Examples include trimethylolethane and trimethylolpropane.

  Examples of the alkylene oxide include ethylene oxide, propylene oxide, butylene oxide, styrene oxide, epichlorohydrin, and tetrahydrofuran.

  As said polyether polyol, since the compatibility with the pigment etc. which are used for ink is good, it is preferable to use a thing with a number average molecular weight of 500-3000.

  Moreover, as said polyol (a1), the polyol (a1-3) which has an alicyclic structure other than an above described polyol can be used.

  Examples of the polyol (a1-3) having an alicyclic structure include cyclobutanediol, cyclopentanediol, 1,4-cyclohexanediol, cycloheptanediol, cyclooctanediol, cyclohexanedimethanol, hydroxypropylcyclohexanol, Cyclohexanediol, butylcyclohexanediol, 1,1′-bicyclohexylidenediol, cyclohexanetriol, hydrogenated bisphenol A, 1,3-adamantanediol, etc. The containing polyol is mentioned. These polyols having an alicyclic structure can be used alone or in combination of two or more.

  Moreover, it is preferable to use the said polyol (a1-3) in the range of 0-20 mass% in the said polyol (a1) whole quantity, since blocking of printed matter can be suppressed.

  Examples of the polyisocyanate (a2) that can react with the polyol (a1) include 4,4′-diphenylmethane diisocyanate, 2,4′-diphenylmethane diisocyanate, carbodiimide-modified diphenylmethane diisocyanate, crude diphenylmethane diisocyanate, phenylene diisocyanate, triene diisocyanate, Aromatic polyisocyanates such as naphthalene diisocyanate, xylylene diisocyanate, tetramethylxylylene diisocyanate; Aliphatic polyisocyanates such as hexamethylene diisocyanate, lysine diisocyanate; Fats such as cyclohexane diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate Cyclic structure Such as polyisocyanates with. These polyisocyanates (a2) can be used alone or in combination of two or more.

  As a method for producing the urethane resin (A) obtained by reacting the polyol (a1) and the polyisocyanate (a2), for example, in the absence of a solvent or in the presence of an organic solvent, the polyol (a1) and Examples include a method in which the polyisocyanate (a2) is mixed and reacted in a reaction temperature range of about 50 ° C to 150 ° C.

  In the reaction of the polyol (a1) and the polyisocyanate (a2), for example, the equivalent ratio of the isocyanate group of the polyisocyanate (a2) to the hydroxyl group of the polyol (a1) is in the range of 0.8 to 2.5. Preferably, it is carried out in the range of 0.9 to 1.5.

  Moreover, as said urethane resin (A), since the blocking of printed matter can be suppressed, it is preferable to use what has an alicyclic structure.

  Examples of the alicyclic structure include a cyclobutyl ring, a cyclopentyl ring, a cyclohexyl ring, a cycloheptyl ring, a cyclooctyl ring, a propylcyclohexyl ring, a tricyclo [5.2.1.2.6] decyl skeleton, and a bicyclo [ 4.3.0] -nonyl skeleton, tricyclo [5.3.1.1] dodecyl skeleton, propyltricyclo [5.3.1.1] dodecyl skeleton, norbornene skeleton, isobornyl skeleton, dicyclopentanyl skeleton, Examples thereof include an adamantyl skeleton. Among these, a cyclohexyl ring structure is preferable.

The alicyclic structure is preferably present in the range of 1000 mmol / kg to 5000 mmol / kg with respect to the entire urethane resin (A) because blocking of printed matter can be suppressed.
Especially, the range of 1000 mmol / kg-4000 mmol / kg is preferable. Moreover, when it is the range of 1000 mmol / kg-3000 mmol / kg, the ink which is very excellent in re-dissolution property and blocking property can be obtained, and it is more preferable.
In addition, the calculation method points out the total mol of the alicyclic structure of preparation with respect to 1 kg of urethane resin solid content.

  The alicyclic structure preferably includes a polyol-derived alicyclic structure having an alicyclic structure that can be used as the polyol (a1) used when the urethane resin (A) is produced. Need not be derived from a polyol having an alicyclic structure, and a part thereof may be derived from an alicyclic structure-containing polyisocyanate such as isophorone diisocyanate.

  In addition, the ratio of the alicyclic structure contained in the said urethane resin (A) with respect to the whole said urethane resin (A) said by this invention is the polyol (a1) used for manufacture of the said urethane resin (A). And the total mass of all raw materials such as polyisocyanate (a2) and the amount of the alicyclic structure contained in the alicyclic structure-containing compound used in the production of the urethane resin (A).

  Moreover, when manufacturing the said urethane resin (A), a chain extender can be used as needed.

  Examples of the chain extender include polyamines, hydrazine compounds, and other compounds having active hydrogen atoms. These chain extenders can be used alone or in combination of two or more.

  Examples of the polyamine include ethylenediamine, 1,2-propanediamine, 1,6-hexamethylenediamine, piperazine, 2,5-dimethylpiperazine, isophoronediamine, 4,4′-dicyclohexylmethanediamine, and 3,3′-. Diamines such as dimethyl-4,4′-dicyclohexylmethanediamine, 1,4-cyclohexanediamine; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylaminopropylamine, N-ethylaminoethylamine, N -Methylaminopropylamine, diethylenetriamine, dipropylenetriamine, triethylenetetramine and the like. Among these, ethylenediamine is preferable.

  Examples of the hydrazine compound include hydrazine, N, N′-dimethylhydrazine, 1,6-hexamethylenebishydrazine, succinic acid dihydrazide, adipic acid dihydrazide, glutaric acid dihydrazide, sebacic acid dihydrazide, isophthalic acid dihydrazide, β-semicarbazide. Examples include propionic acid hydrazide, 3-semicarbazide-propyl-carbazate, semicarbazide-3-semicarbazidemethyl-3,5,5-trimethylcyclohexane, and the like.

  Examples of the other active hydrogen-containing compounds include ethylene glycol, diethylene recall, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, 1,4-butanediol, hexamethylene glycol, Glycols such as saccharose, methylene glycol, glycerin, sorbitol; phenols such as bisphenol A, 4,4′-dihydroxydiphenyl, 4,4′-dihydroxydiphenyl ether, 4,4′-dihydroxydiphenylsulfone, hydrogenated bisphenol A, hydroquinone, Water etc. are mentioned.

  For example, when a polyamine is used as the chain extender, the equivalent ratio [amino group / isocyanate group] of the amino group and isocyanate group of the polyamine is preferably 1.2 or less, more preferably in the range of 0.3 to 1. preferable.

  Examples of the organic solvent that can be used in producing the urethane resin (A) include ketone solvents such as acetone and methyl ethyl ketone; ether solvents such as tetrahydrofuran and dioxane; acetate solvents such as ethyl acetate and butyl acetate; acetonitrile and the like. Nitrile solvents of the following: amide solvents such as dimethylformamide and N-methylpyrrolidone. These organic solvents can be used alone or in combination of two or more.

  In addition, in order to reduce the burden on safety and the environment, the organic solvent removes part or all of the organic solvent by, for example, distilling under reduced pressure during or after the production of the urethane resin (A). May be.

The urethane resin (A) obtained by the above method preferably has a weight average molecular weight in the range of 5,000 to 500,000 because the durability of the printed material can be expressed. 5,000 to 200, It is more preferable to use those having a weight average molecular weight in the range of 000, and it is more preferable to use a weight average molecular weight in the range of 20,000 to 100,000.
In addition, the measurement of the weight average molecular weight (polystyrene conversion) by GPC (gel permeation chromatography) in this invention was performed on condition of the following using the Tosoh Corporation HLC8220 system.
Separation column: Four TSKgelGMHHR-N manufactured by Tosoh Corporation are used. Column temperature: 40 ° C. Moving layer: Tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd. Flow rate: 1.0 ml / min. Sample concentration: 0.4% by mass. Sample injection volume: 100 microliters. Detector: differential refractometer.

  When the weight average molecular weight is less than 5,000, not only the durability of the printed matter is lowered, but also various problems such as blocking due to poor drying tend to occur, and when the molecular weight exceeds 500,000. Are liable to cause problems such as poor ink transfer and poor re-dissolvability.

  Moreover, the water-based conversion of the urethane resin (A) produced by the above method can be performed, for example, by the following method.

  [Method 1] After neutralizing part or all of the acid groups of the aqueous urethane resin obtained by reacting the polyol (a1) and the polyisocyanate (a2), the aqueous medium (B) is added to disperse in water. And then, the urethane resin (A) is dispersed in water by chain extension using the chain extender.

  [Method 2] Aqueous urethane resin obtained by reacting polyol (a1) and polyisocyanate (a2) and a chain extender similar to the above are charged in a reaction vessel in a batch or divided, and chain extension is performed. Method of producing urethane resin (A) by reacting, then neutralizing part or all of the acid groups in the obtained urethane resin (A), and then adding aqueous medium (B) to disperse in water .

  In [Method 1] to [Method 2], an emulsifier may be used as necessary. In addition, when water is dissolved or dispersed, a machine such as a homogenizer may be used as necessary.

  Examples of the aqueous medium (B) include water, organic solvents miscible with water, and mixtures thereof. Examples of the organic solvent miscible with water include alcohol solvents such as methanol, ethanol, n-propanol and isopropanol; ketone solvents such as acetone and methyl ethyl ketone; polyalkylene glycols such as ethylene glycol, diethylene glycol and propylene glycol; Alkyl ethers; lactam solvents such as N-methyl-2-pyrrolidone and the like. In the present invention, only water may be used, a mixture of water and an organic solvent miscible with water may be used, or only an organic solvent miscible with water may be used.

  The aqueous medium (B) is preferably water alone or a mixture of water and an organic solvent miscible with water, particularly water alone, from the viewpoint of safety and environmental load.

  Examples of the emulsifier include nonionic emulsifiers such as polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene styryl phenyl ether, polyoxyethylene sorbitol tetraoleate, and polyoxyethylene / polyoxypropylene copolymer. Fatty acid salts such as sodium oleate, alkyl sulfate esters, alkyl benzene sulfonates, alkyl sulfosuccinates, naphthalene sulfonates, polyoxyethylene alkyl sulfates, alkane sulfonate sodium salts, sodium alkyl diphenyl ether sulfonates, etc. Anionic emulsifiers; Cationic emulsifiers such as alkylamine salts, alkyltrimethylammonium salts, and alkyldimethylbenzylammonium salts . Among these, an anionic or nonionic emulsifier is preferable from the viewpoint of maintaining the excellent storage stability of the aqueous flexo ink of the present invention.

The binder for aqueous liquid ink of the present invention in which the urethane resin (A) obtained by the above method is dispersed in the aqueous medium (B), the urethane resin (A) is 20 to 20% of the total solid content of the aqueous liquid ink. It is preferably contained in the range of 75% by mass and in the range of 10 to 50% by mass with respect to the total amount of the aqueous liquid ink. By setting the urethane resin (A) in the range of 20 to 75% by mass with respect to the total amount of the solid content of the aqueous liquid ink, the adhesion to the base material is improved, while 10 to 50 with respect to the total amount of the aqueous liquid ink. By setting it as the range of the mass%, it is preferable in the re-dissolution property of the water-based ink at the time of printing, suppression of blocking of printed matter, and improvement of printing density.
Other resins that can be blended with the aqueous liquid ink binder of the present invention are preferably water-based or water-dispersible resins, particularly those having an acid value of 5 to 150 mgKOH / g, such as acrylic resins and styrene acrylic resins. Maleic acid resin, styrene maleic acid resin, α-olefin maleic acid resin, ester resin, sulfonic acid resin, phosphoric acid resin and the like. Of these, styrene / maleic acid copolymers are preferred. Further, when the styrene / maleic acid copolymer is taken as an example, the addition amount is preferably 1 to 10% by mass with respect to the total amount of the liquid ink. In addition, a part of the resin may function as a pigment dispersant.

  Examples of the pigment used in the aqueous liquid ink using the binder for the aqueous liquid ink of the present invention include organic and inorganic pigments and dyes used in general inks, paints, and recording agents.

  Examples of the organic pigment include azo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, azomethine azo, dictopyrrolopyrrole, and isoindoline. These pigments are mentioned. Indigo ink is copper phthalocyanine, and transparent yellow ink is C.I. I. Pigment No Yellow 83 is preferably used.

Examples of the inorganic pigment include carbon black, titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, bengara, aluminum, mica (mica), and the like. Further, a luster pigment (Metashine; Nippon Sheet Glass Co., Ltd.) having glass or block flake as a base material and coated with metal or metal oxide can be used. From the viewpoints of cost and coloring power, it is preferable to use titanium oxide for white ink, carbon black for black ink, aluminum for silver ink, and mica for pearl ink. Aluminum is in the form of powder or paste, but is preferably used in the form of paste from the viewpoint of handling and safety, and whether to use leafing or non-leafing is appropriately selected from the viewpoint of brightness and concentration.
The total amount of the pigment is preferably contained in an amount sufficient to ensure the density and coloring power of the ink, that is, in a ratio of 1 to 50% by mass with respect to the total weight of the ink. Moreover, a coloring agent can be used individually or in combination of 2 or more types.

The aqueous liquid ink using the aqueous liquid ink binder of the present invention can further use a solvent and other auxiliary agents according to the purpose.
As the solvent, water alone or an organic solvent miscible with water can be used. Examples of the organic solvent include alcohols such as methyl alcohol, ethyl alcohol, isopropyl alcohol and n-propyl alcohol, polyhydric alcohols such as propylene glycol and glycerin, propylene glycol monomethyl ether, propylene glycol monoethyl ether, and propylene glycol mono n. -Ethers such as propyl ether and ethyl carbitol.

  Other auxiliary ingredients include waxes such as paraffin wax, polyethylene wax, carnauba wax, oleic acid amide, stearic acid amide, erucic acid amide, etc. for imparting friction resistance, slipperiness, etc. Fatty acid amides, silicon-based and non-silicon-based antifoaming agents for suppressing foaming at the time of printing, various dispersants for improving pigment wetting, and the like can also be used as appropriate.

The aqueous printing ink composition according to the present invention is produced using an Eiger mill, a sand mill, a gamma mill, an attritor or the like generally used for the production of gravure and flexographic printing inks.
The aqueous liquid ink obtained using the binder for aqueous liquid ink of the present invention, when used as an aqueous flexo ink, has a viscosity of 7 to 25 seconds at 25 ° C. using Zaan Cup # 4 manufactured by Kouaisha. Well, more preferably 10 to 20 seconds. Moreover, 25-50 mN / m is preferable and, as for the surface tension in 25 degreeC of the obtained water-based flexographic printing ink, it is more preferable if it is 33-43 mN / m. The lower the surface tension of the ink, the better the wettability of the ink to the substrate such as a fill. However, when the surface tension is below 25 mN / m, the ink wetting spreads, so that the halftone dots adjacent to each other are halftone. Tend to be connected, and it is easy to cause smearing on the printing surface called dot bridge. On the other hand, when the surface tension exceeds 50 mN / m, the wettability of the ink with respect to the substrate such as a film is lowered, which tends to cause repelling.
On the other hand, when using it as a water-based gravure ink, the viscosity should just be 7-25 seconds at 25 degreeC using the Zahn cup # 3 made from Kogosha, More preferably, it is 10-20 seconds. Further, the surface tension at 25 ° C. of the obtained aqueous gravure ink is preferably 25 to 50 mN / m, and more preferably 33 to 43 mN / m, similarly to the aqueous flexo ink. The lower the surface tension of the ink, the better the wettability of the ink to the substrate such as a fill. However, when the surface tension is below 25 mN / m, the ink wetting spreads, so that the halftone dots adjacent to each other are halftone. Tend to be connected, and it is easy to cause smearing on the printing surface called dot bridge. On the other hand, when the surface tension exceeds 50 mN / m, the wettability of the ink with respect to the substrate such as a film is lowered, which tends to cause repelling.

The aqueous liquid ink obtained by using the binder for aqueous liquid ink of the present invention has excellent adhesion to various substrates and can be used for printing on paper, synthetic paper, thermoplastic resin film, plastic product, steel plate and the like.
As the base film, polyamide resins such as Ny6, nylon 66, nylon 46, etc., polyester resins such as PET, polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, poly Biodegradable resins represented by aliphatic polyester resins such as polyhydroxycarboxylic acids such as lactic acid, poly (ethylene succinate), poly (butylene succinate), polyolefin resins such as PP and polyethylene, polyimide resins, polyarylate Examples thereof include a film made of a thermoplastic resin such as a resin or a mixture thereof, and a laminate thereof. Among these, a film made of polyester, polyamide, polyethylene, or polypropylene can be preferably used. These base films may be unstretched films or stretched films, and the production method is not limited. Moreover, although the thickness of a base film is not specifically limited, Usually, what is necessary is just to be the range of 1-500 micrometers.
Moreover, it is preferable that the printing surface of the base film is subjected to corona discharge treatment. Further, silica, alumina or the like may be deposited.

  Hereinafter, the present invention will be specifically described by way of examples and comparative examples.

(Synthesis Example 1: Preparation of binder (1) for aqueous liquid ink)
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 191 parts by mass of polyoxytetramethylene glycol (molecular weight 2000), 141 parts by mass of isophorone diisocyanate, 26 parts by mass of 2,2-dimethylolpropionic acid And an organic solvent solution of a urethane prepolymer having an isocyanate group at the molecular terminal was obtained by reacting in a mixed solvent of 28 parts by mass of 1,4-cyclohexanedimethanol and 200 parts by mass of methyl ethyl ketone.
Next, 20 parts by mass of 50% aqueous potassium hydroxide solution was added to neutralize part or all of the carboxyl groups of the urethane prepolymer, and 700 parts by mass of water and 9.0 parts by mass of 80% hydrazine aqueous solution were further added. The aqueous dispersion of urethane resin was obtained by stirring the mixture, and then the binder (1) for aqueous liquid ink having a nonvolatile content of 40% by mass was obtained by aging and solvent removal.
In this aqueous liquid ink binder (1), the ratio of the alicyclic structure in the urethane resin was 2067 mmol / kg, and the acid value was 28.
In addition, the calculation method points out the total mol of the alicyclic structure of preparation with respect to 1 kg of urethane resin solid content.

(Synthesis Example 2: Preparation of aqueous liquid ink binder (2))
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 256 parts by mass of polyoxytetramethylene glycol (molecular weight 2000), 102 parts by mass of isophorone diisocyanate, 23 parts by mass of 2,2-dimethylolpropionic acid And an organic solvent solution of a urethane prepolymer having an isocyanate group at the molecular terminal was obtained by reacting in a mixed solvent of 6.5 parts by mass of neopentyl glycol and 200 parts by mass of methyl ethyl ketone.
Next, 18 parts by mass of 50% aqueous potassium hydroxide solution was added to neutralize part or all of the carboxyl groups of the urethane prepolymer, and 700 parts by mass of water and 6.5 parts by mass of 80% hydrazine aqueous solution were further added. To obtain an aqueous dispersion of urethane resin, and then aging and solvent removal to obtain an aqueous liquid ink binder (2) having a nonvolatile content of 40% by mass.
The ratio of the alicyclic structure in the urethane resin in the aqueous liquid ink binder (2) was 1150 mmol / kg, and the acid value was 25.

(Synthesis Example 3: Preparation of binder (3) for aqueous liquid ink)
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 263 parts by mass of polyoxytetramethylene glycol (molecular weight 2000), 98 parts by mass of isophorone diisocyanate, 22 parts by mass of 2,2-dimethylolpropionic acid Part, and 5.6 parts by mass of 1,4-cyclohexanedimethanol and 200 parts by mass of methyl ethyl ketone were reacted to obtain an organic solvent solution of a urethane prepolymer having an isocyanate group at the molecular end.
Next, 17 parts by mass of 50% aqueous potassium hydroxide solution was added to neutralize part or all of the carboxyl groups of the urethane prepolymer, and 700 parts by mass of water and 6.2 parts by mass of 80% hydrazine aqueous solution were further added. The aqueous dispersion of urethane resin was obtained by stirring the mixture, and then the binder (3) for aqueous liquid ink having a nonvolatile content of 40% by mass was obtained by aging and solvent removal.
The ratio of the alicyclic structure in the urethane resin in the binder (3) for aqueous liquid ink was 1198 mmol / kg, and the acid value was 23.

(Synthesis Example 4: Preparation of binder (4) for aqueous liquid ink)
7. In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 250 parts by mass of polyoxytetramethylene glycol (molecular weight 2000), 109 parts by mass of isophorone diisocyanate, 2,2-dimethylolpropionic acid By reacting in 6 parts by mass, a mixed solvent of 26 parts by mass of 1,4-cyclohexanedimethanol and 200 parts by mass of methyl ethyl ketone, an organic solvent solution of a urethane prepolymer having an isocyanate group at the molecular end was obtained.
Next, 6.8 parts by mass of 50% aqueous potassium hydroxide solution was added to neutralize part or all of the carboxyl groups of the urethane prepolymer, and 700 parts by mass of water and 6.9 parts by mass of 80% hydrazine aqueous solution were added. In addition, an aqueous dispersion of a urethane resin was obtained by sufficiently stirring, and then an aqueous liquid ink binder (4) having a nonvolatile content of 40% by mass was obtained by aging and solvent removal.
The ratio of the alicyclic structure in the urethane resin in the binder (4) for aqueous liquid ink was 1671 mmol / kg, and the acid value was 9.

(Synthesis Example 5: Preparation of binder (5) for aqueous liquid ink)
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas inlet tube, and a stirrer, 113 parts by mass of polyoxytetramethylene glycol (molecular weight 2000), 178 parts by mass of isophorone diisocyanate, 17 parts by mass of 2,2-dimethylolpropionic acid Part, and 84 parts by mass of 1,4-cyclohexanedimethanol and 200 parts by mass of methyl ethyl ketone were reacted to obtain an organic solvent solution of a urethane prepolymer having an isocyanate group at the molecular end.
Next, 13 parts by weight of 50% aqueous potassium hydroxide solution was added to neutralize part or all of the carboxyl groups of the urethane prepolymer, and 700 parts by weight of water and 2.2 parts by weight of 80% hydrazine aqueous solution were further added. To obtain a water dispersion of urethane resin, and then aging and solvent removal to obtain a binder (5) for aqueous liquid ink having a nonvolatile content of 40% by mass.
The ratio of the alicyclic structure in the urethane resin in the aqueous liquid ink binder (5) was 3459 mmol / kg, and the acid value was 18.

(Comparative Synthesis Example 1: Preparation of binder (6) for aqueous liquid ink)
196 parts by mass of polyoxytetramethylene glycol (molecular weight 2000), 145 parts by mass of isophorone diisocyanate, 26 parts by mass of 2,2-dimethylolpropionic acid in a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer And an organic solvent solution of a urethane prepolymer having an isocyanate group at the molecular terminal was obtained by reacting in a mixed solvent of 28 parts by mass of 1,4-cyclohexanedimethanol and 200 parts by mass of methyl ethyl ketone.
Next, 19 parts by mass of triethylamine is added to neutralize part or all of the carboxyl groups of the urethane prepolymer, and 700 parts by mass of water and 9.2 parts by mass of an 80% hydrazine aqueous solution are added and sufficiently stirred. Thus, an aqueous dispersion of urethane resin was obtained, followed by aging and solvent removal to obtain an aqueous liquid ink binder (6) having a nonvolatile content of 40% by mass.
In this aqueous liquid ink binder (6), the ratio of the alicyclic structure in the urethane resin was 2120 mmol / kg, and the acid value was 28.

(Comparative Synthesis Example 2: Preparation of binder (7) for aqueous liquid ink)
In a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer, 291 parts by mass of polyoxytetramethylene glycol (molecular weight 2000), 80 parts by mass of isophorone diisocyanate, 16 parts by mass of 2,2-dimethylolpropionic acid And an organic solvent solution of a urethane prepolymer having an isocyanate group at the molecular terminal was obtained by reaction in a mixed solvent of 4.9 parts by weight of neopentyl glycol and 200 parts by weight of methyl ethyl ketone.
Next, 13 parts by mass of 50% aqueous potassium hydroxide solution was added to neutralize part or all of the carboxyl groups of the urethane prepolymer, and 700 parts by mass of water and 3.4 parts by mass of 80% hydrazine aqueous solution were added. By sufficiently stirring, an aqueous dispersion of urethane resin was obtained, and then aging and solvent removal were performed to obtain an aqueous liquid ink binder (7) having a nonvolatile content of 40% by mass.
The ratio of the alicyclic structure in the urethane resin in the binder (7) for aqueous liquid ink was 901 mmol / kg, and the acid value was 17.

(Comparative synthesis example 3: Preparation of binder (8) for aqueous liquid ink)
196 parts by mass of polyoxytetramethylene glycol (molecular weight 2000), 145 parts by mass of isophorone diisocyanate, 26 parts by mass of 2,2-dimethylolpropionic acid in a nitrogen-substituted container equipped with a thermometer, a nitrogen gas introduction tube, and a stirrer And an organic solvent solution of a urethane prepolymer having an isocyanate group at the molecular terminal was obtained by reacting in a mixed solvent of 28 parts by mass of 1,4-cyclohexanedimethanol and 200 parts by mass of methyl ethyl ketone.
Next, 13 parts by mass of 25% aqueous ammonia solution was added to neutralize part or all of the carboxyl groups of the urethane prepolymer, and 700 parts by mass of water and 9.2 parts by mass of 80% hydrazine aqueous solution were further added. By stirring, an aqueous dispersion of urethane resin was obtained, and then aging and solvent removal were performed to obtain an aqueous liquid ink binder (8) having a nonvolatile content of 40% by mass.
In this aqueous liquid ink binder (8), the ratio of the alicyclic structure in the urethane resin was 2120 mmol / kg, and the acid value was 28.

[Production of water-based flexographic ink]
Using each of the aqueous liquid ink binders obtained in Synthesis Examples 1 to 5 and Comparative Synthesis Examples 1 to 3, the flexographic inks were thoroughly stirred and mixed with the following composition, and then kneaded in a bead mill and then kneaded base ink Then, 10 parts of “aqueous liquid ink binder” and 4 parts of water were further mixed with the kneaded meat base ink to prepare an aqueous blue flexographic printing ink. The viscosity of the obtained flexographic printing ink was adjusted with water (+ α) so that the viscosity would be 16 seconds (25 ° C.) with Zahn Cup # 4 (manufactured by Kosei Co., Ltd.).
Moreover, in order to confirm the surface tension of the obtained flexographic printing ink, the surface tension at 25 ° C. was measured.
The surface tension measurement method was based on the Whihelmy method, and was performed using an automatic surface tension meter DY-300 manufactured by Kyowa Interface Science Co., Ltd.

[Containing kneaded meat base ink]
FASTPGEN BLUE LA5380 indigo pigment (DIC) 15 parts Binder for aqueous liquid ink 40 parts Nonionic pigment dispersant (BYK) 10 parts Isopropyl alcohol 3 parts Water 8 parts Silicone defoamer (BYK) 0. 2 parts

[Total amount of final aqueous blue flexo ink blended (excluding water for viscosity adjustment)]
FASTPGEN BLUE LA5380 indigo pigment (manufactured by DIC) 15 parts binder for aqueous liquid ink 50 parts nonionic pigment dispersant (manufactured by BYK) 10 parts isopropyl alcohol 3 parts water 12 parts + α
(Adjusted with Zaan Cup # 4)
Silicone defoamer (byk) 0.2 part

  Examples 1 to 5 and Comparative Examples 1 to 3 which are blue flexographic inks with viscosity adjustments described above are shown in Table 1 using a Flexoprof 100 test printing machine (Testing Machines, Inc., Anilox 200 line / inch). Corona-treated polyethylene terephthalate (PET) film shown (Easter E5102, manufactured by Toyobo Co., Ltd., 12 μm thick), corona-treated polypropylene (OPP) biaxially stretched film (Pyrene P2161, manufactured by Toyobo Co., Ltd., 20 μm thick), 240 mm long X After printing a solid pattern with a width of 80 mm, it was dried with a dryer to obtain a printed matter.

[Production of water-based gravure ink]
Using each of the aqueous liquid ink binders obtained in Synthesis Examples 1 to 5 and Comparative Synthesis Examples 1 to 3, each gravure printing ink was thoroughly agitated and mixed with the following composition, and then kneaded with a bead mill, and then the kneaded base ink Then, 10 parts of “aqueous liquid ink binder” and 9 parts of water were further mixed with the kneaded meat base ink to prepare an aqueous blue gravure printing ink. The viscosity of the obtained gravure printing ink was adjusted with water (+ α) so that the viscosity would be 16 seconds (25 ° C.) with Zahn Cup # 3 (manufactured by Kosei Co., Ltd.).
Moreover, in order to confirm the surface tension of the obtained gravure printing ink, the surface tension at 25 degreeC was measured.
The surface tension measurement method was based on the Whihelmy method, and was performed using an automatic surface tension meter DY-300 manufactured by Kyowa Interface Science Co., Ltd.

[Containing kneaded meat base ink]
FASTPGEN BLUE LA5380 indigo pigment (made by DIC) 15 parts binder for aqueous liquid ink 40 parts nonionic pigment dispersant (made by BYK) 10 parts isopropyl alcohol 3 parts water 8 parts silicon-based antifoaming agent (made by BYK) 0. 2 parts

[Total amount of final aqueous blue gravure ink blended (excluding water for viscosity adjustment)]
FASTPGEN BLUE LA5380 indigo pigment (made by DIC) 15 parts binder for aqueous liquid ink 50 parts nonionic pigment dispersant (made by BYK) 10 parts isopropyl alcohol 3 parts water 17 parts + α
(Adjusted with Zaan Cup # 3)
Silicone defoamer (byk) 0.2 part

  Corona treatment similar to Table 1 using the gravure proofing machine provided with Examples 6-10 and Comparative Examples 4-6 shown in Table 2 which are the above-described blue-gravure printing inks with adjusted viscosity and a plate depth of 25 μm. Polyethylene terephthalate (PET) film (Ester E5102, manufactured by Toyobo Co., Ltd., thickness 12 μm), corona-treated polypropylene (OPP) biaxially stretched film (Toyobo Co., Ltd., Pyrene P2161, thickness 20 μm), length 240 mm × width 80 mm After printing the solid pattern, it was dried with a dryer to obtain a printed matter.

  The obtained flexographic prints and gravure prints were evaluated for redissolvability, blocking resistance, and substrate adhesion when each film was used, and ink transferability was confirmed by printing density.

[Evaluation item 1: Re-solubility]
One drop of distilled water was dropped on the ink coating surface of the printed matter with a dropper and quickly wiped off with gauze.
After wiping, the time until the coating film did not dissolve was measured and evaluated.
A: After dropping, the coating film is dissolved for less than 3 seconds.
◯: Dissolves within 3 seconds to less than 5 seconds after dropping.
Δ: Dissolves in 5 seconds to less than 7 seconds after dropping.
X: It takes 7 seconds or more to dissolve the coating film.

[Evaluation item 2: Blocking resistance]
Cut the film into 4cm x 4cm size so that the printed surface and non-printed surface of the printed material are in contact with each other, apply the load of 5Kgf / cm ² and leave it in an environment of 40 ° C for 12 hours. The state of ink transfer (set-off) to the non-printing surface when peeled was visually determined based on the area ratio (%) of the set-up portion.
(Double-circle): The transition to a non-printing surface is not seen at all.
○: Slightly less than 5%, but transfer due to settling is observed.
(Triangle | delta): Transfer by see-through of 5% or more and less than 20% is seen.
X: Transition due to set-off of 20% or more is observed.

[Evaluation item 3: Adhesion of substrate]
After leaving the printed material for a day, paste the cellophane tape (Nichiban 12mm width) on the printed surface and quickly peel off one end of the cellophane tape in the direction perpendicular to the printed surface. The appearance was visually judged based on the above.
A: The printed film is not peeled off at all.
○: 80% or more to less than 90% of the printed film remained on the film.
Δ: 50% to less than 80% of the printed film remained on the film.
X: Less than 50% of the printed film remained on the film.

[Evaluation item 4: Ink transfer properties]
The solid density of the printed matter was evaluated for ink transfer property using a SpectroEye densitometer manufactured by X-Rite.
A: The indigo density of the printed matter is 1.9 or more, and the printability is good.
(Triangle | delta): The indigo density of printed matter is 1.6 or more and less than 1.9, and printability is medium.
X: The indigo density of the printed matter is less than 1.6, and the printability is poor.

  Table 1 shows the evaluation results of the aqueous blue flexo ink.

  The evaluation results of the aqueous blue gravure ink are shown in Table 2.

  In the aqueous liquid ink using the binder for aqueous liquid ink of the present invention, by adjusting the Zahn cup viscosity, in any printing system of flexo and gravure, while maintaining the adhesion to the substrate, ink transferability, Both blocking resistance and ink re-dissolvability can be achieved.

Claims (7)

A water-based flexographic ink or water-based gravure ink containing water as a water-based liquid ink binder, pigment, and water-based medium, wherein the water-based liquid ink binder includes an acid group-containing polyol (a1-1),
A polyol (a1) containing a polyether polyol (a1-2) other than the polyol (a1-1), a urethane resin (A) that is a reaction product of the polyisocyanate (a2), and an aqueous medium (B). A binder for aqueous liquid ink containing,
The acid group of the urethane resin (A) is neutralized with a metal salt,
The urethane resin (A) includes an alicyclic structure in a range of 1000 to 5000 mmol / kg with respect to the entire urethane resin (A).
Aqueous flexographic ink or aqueous gravure ink, wherein the urethane resin (A) has an acid value in the range of 10 to 50 (Bionano nano having an average diameter of 1 nm to 100 nm and an aspect ratio of 100 or more Unless including fiber) .   The water-based flexographic ink or water-based gravure ink according to claim 1, wherein the surface tension at 25 ° C is 25 to 50 mN / m.   The water-based flexographic ink or water-based gravure ink according to claim 1, wherein the surface tension at 25 ° C is 33 to 43 mN / m.   The aqueous flexo ink or aqueous gravure ink according to any one of claims 1 to 3, wherein the aqueous medium is water or a mixture of water and an alcohol solvent. An aqueous flexographic ink or aqueous gravure ink according to any one of claims 1 to 4, a viscosity of aqueous flexographic ink is 7 to 25 seconds at using Zahn Cup # 4 25 ° C., or, viscosity, in using the Zahn cup # 3 25 ° C. 7 to 25 Byodea Ru water soluble gravure inks.   A printed matter, which is subjected to flexographic printing with the aqueous flexographic ink according to claim 1.   Gravure printing is given with the water-based gravure ink as described in any one of Claims 1-5, The printed matter characterized by the above-mentioned.