JPH11228655A - Polyurethane emulsion for water-based printing ink and water-based printing ink using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyurethane emulsion used as a vehicle of an aqueous printing ink, and an aqueous printing ink excellent in adhesion and printability. SOLUTION: (A) a polyol, (B) a chain extender,
An aqueous emulsion of a polyurethane polymer obtained by reacting (C) a compound containing a carboxyl group and an active hydrogen group, (D) an organic polyisocyanate, and (E) a neutralizing agent. The problem is solved by a polyurethane emulsion for aqueous printing ink, wherein the temperature is less than 35 ° C., and an aqueous printing ink using the above-mentioned polyurethane emulsion.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polyurethane emulsion used as a vehicle for an aqueous printing ink having excellent adhesion and printability, and an aqueous printing ink using the same.

[0002]

2. Description of the Related Art In the field of printing inks, organic solvent-based inks have been mainly used. However, in recent years, from the viewpoints of air pollution prevention, regulations under the Fire Service Law, occupational health and safety, etc., aqueous printing inks have been used. The performance of such an aqueous printing ink largely depends on the characteristics of the resin used as a vehicle, and a resin in which a carboxylate is introduced into a molecular chain, for example, a polyester resin, an acrylic resin, a polyurethane resin, and the like have been proposed. ing. In particular, polyurethane resins are widely used in organic solvent-based printing inks because of their good adhesion to various plastic films. However, various studies have been made on polyurethane resins for aqueous printing inks because they are inferior in performance to organic resin-based resins.

For example, JP-A-5-171091 discloses an aqueous printing ink using an aqueous emulsion of a polyurethane resin using polycarbonate diol. Also, JP-A-6-346012 discloses that
A binder for an aqueous printing ink using an aqueous emulsion of a polyurethane resin having a nonionic and anionic hydrophilic group introduced therein is disclosed.

[0004]

In an aqueous emulsion, the resin is not dissolved in water. Therefore, to apply an organic solvent-based printing system to a system using an aqueous emulsion printing ink as it is, Problems such as poor drying, poor ink adhesion, and cracking of the ink film may occur.

The present invention provides a polyurethane emulsion used as a vehicle for aqueous printing inks,
An object of the present invention is to provide an aqueous printing ink excellent in printability.

[0006]

That is, the present invention provides the following (1) and (2). (1) (A) a polyol having a number average molecular weight of 500 to 10,000, (B) a chain extender, (C) a compound containing a carboxyl group and an active hydrogen group, (D) an organic polyisocyanate, and (E) neutralization. A water-based emulsion of a polyurethane polymer obtained by reacting an agent, wherein the minimum film formation temperature of the water-based emulsion is lower than 35 ° C.

(2) An aqueous printing ink using the polyurethane emulsion of (1).

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The polyol (A) used in the polyurethane emulsion of the present invention has a number average molecular weight of 5
00 to 10,000, preferably 1,000 to 5,000
0. The average number of functional groups of the polyol (A) is preferably 2 to 4, more preferably 2 to 3. When the number average molecular weight of the polyol is less than the lower limit, the ink film tends to be too hard. If the upper limit is exceeded, the blocking resistance tends to be insufficient. Examples of the polyol used in the present invention include a polyester polyol, a polyamide ester polyol, a polyether polyol, a polyether ester polyol, a polycarbonate polyol, a polyolefin polyol, and an animal and plant polyol. The preferred polyol (A) in the present invention is a polyester polyol when importance is attached to adhesion, and a polyether polyol or polycarbonate polyol when importance is attached to water resistance. In addition, the number average molecular weight of the polyol was calculated from the average number of functional groups and the amount of terminal groups determined by a terminal group determination method.

Examples of the polyester polyol include known phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, succinic acid, tartaric acid, oxalic acid, malonic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, curtaconic acid, Azelaic acid, sebacic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, 1,4-
Cyclohexyldicarboxylic acid, α-hydromuconic acid,
one or more kinds of dicarboxylic acids or anhydrides such as β-hydromuconic acid, α-butyl-α-ethylglutaric acid, α, β-diethylsuccinic acid, maleic acid, and fumaric acid; ethylene glycol; Propanediol, 1,3
-Propanediol, 1,2-butanediol, 1,3
-Butanediol, 1,4-butanediol, 1,5-
Pentanediol, 1,6-hexanediol, 1,8
-Octanediol, 1,9-nonanediol, 3-methyl-1,5-pentanediol, 3,3-dimethylolheptane, diethylene glycol, dipropylene glycol, neopentyl glycol, diethylene glycol, dipropylene glycol, cyclohexane-1, 4
-Diol, cyclohexane-1,4-dimethanol,
Polycondensation with one or more low molecular polyols such as dimer acid diol, ethylene oxide and propylene oxide adducts of bisphenol A, bis (β-hydroxyethyl) benzene, xylylene glycol, glycerin, trimethylolpropane, and pentaerythritol. Obtained from the reaction. Further, there are lactone-based polyester polyols obtained by ring-opening polymerization of cyclic ester (so-called lactone) monomers such as ε-caprolactone, alkyl-substituted ε-caprolactone, δ-valerolactone, and alkyl-substituted δ-valerolactone. Further, a part of the low molecular polyol may be a low molecular polyamine such as hexamethylenediamine, isophoronediamine, monoethanolamine, or a low molecular amino alcohol. In this case, a polyester-amide polyol is obtained.

Examples of the polyether polyols include low-molecular-weight polyols used in the above-mentioned polyester polyols and low-molecular-weight polyamines such as ethylenediamine, propylenediamine, toluenediamine, metaphenylenediamine, diphenylmethanediamine, and xylylenediamine. Using a compound having two or more, preferably two to three hydrogen groups as an initiator, alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide, alkyl glycidyl ethers such as methyl glycidyl ether, phenyl glycidyl ether, etc. Can be obtained by addition polymerization from a single product or a mixture of cyclic ether monomers such as aryl glycidyl ethers and tetrahydrofuran by a known method.

The polycarbonate polyol is obtained by a dealcoholation reaction or a dephenolization reaction of at least one of the above-mentioned low molecular weight diols and low molecular weight triols of the polyester polyol with ethylene carbonate, diethyl carbonate and diphenyl carbonate. In addition,
Transesterified products of the above-mentioned polycarbonate polyol and polyester polyol can also be suitably used.

As the polyetherester polyol, there is a copolyol obtained from the above-mentioned polyether polyol and the above-mentioned dicarboxylic acid. In addition, there are those obtained by the reaction of the above-mentioned polyester or polycarbonate with epoxide or cyclic ether.

Examples of the polyolefin polyol include polybutadiene having two or more hydroxyl groups, hydrogenated polybutadiene, polyisoprene, and hydrogenated polyisoprene.

Examples of animal and plant-based polyols include castor oil-based polyols and silk fibroin.

The number average molecular weight is from 500 to 10,000.
0 and an average of at least one active hydrogen group in one molecule, epoxy resin, polyamide resin, polyester resin, acrylic resin, rosin in addition to dimer acid polyol and hydrogenated dimer acid polyol. resin,
Active hydrogen group-containing resins such as urea resins, melamine resins, phenol resins, coumarone resins, and polyvinyl alcohol can also be used.

As the chain extender (B) used in the present invention, low molecular polyols used for obtaining the above-mentioned polyester polyol and polyether polyol,
Examples thereof include amino alcohols such as monoethanolamine, diethanolamine, N-methyldiethanolamine, and N-phenyldipropanolamine. Preferred chain extenders in the present invention are aliphatic polyols, alicyclic polyols, aliphatic polyamines and alicyclic polyamines having 2 to 15 carbon atoms.

The compound (C) containing a carboxyl group and an active hydrogen group used in the present invention includes dimethylolpropionic acid, dimethylolbutanoic acid, a reaction product of a polyamine with an acid anhydride, dimethylolpropionic acid, Lactone adducts using dimethylolbutanoic acid as an initiator are exemplified. Preferred compounds (C) having a carboxyl group and an active hydrogen group in the present invention are dimethylolpropionic acid and dimethylolbutanoic acid.

The (D) organic polyisocyanate used in the present invention includes 2,4-toluene diisocyanate, 2,6-toluene diisocyanate, 2,2'-diphenylmethane diisocyanate, 2,4'-diphenylmethane diisocyanate, Aromatic diisocyanates such as 4'-diphenylmethane diisocyanate, diphenyldimethylmethane diisocyanate, dibenzyl diisocyanate, naphthylene diisocyanate, phenylene diisocyanate, xylylene diisocyanate, tetramethyl xylylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (hereinafter abbreviated as HDI) ), Lysine diisocyanate, 2-methylpentane-1,5-diisocyanate,
3-methylpentane-1,5-diisocyanate, 2,
2,4-trimethylhexahylene-1,6-diisocyanate, 2,4,4-trimethylhexahylene-
Aliphatic diisocyanates such as 1,6-diisocyanate, isophorone diisocyanate (hereinafter abbreviated as IPDI), cyclohexyl diisocyanate, hydrogenated xylylene diisocyanate (hereinafter abbreviated as H ₆ XDI), hydrogenated diphenylmethane diisocyanate (hereinafter H ₁₂ MDI), and alicyclic diisocyanates such as hydrogenated trimethylxylylene diisocyanate. These organic diisocyanates can be used alone or as a mixture. Furthermore, these adduct modified products, carbodiimide modified products,
Modified products such as allophanate modified product, buret modified product, uretdione modified product, uretoimine modified product, and isocyanurate modified product can also be used. In these (D) organic polyisocyanates, HDI, IPDI, H ₆ XDI, and H ₁₂ MD are considered in consideration of weather resistance and adhesion when formed into a paint.
I is preferred.

The neutralizing agent (E) used in the present invention includes ammonia, ethylamine, trimethylamine, triethylamine, triisopropylamine, tributylamine, triethanolamine, N-methyldiethanolamine, N-phenyldiethanolamine and monoethanol. Organic amines such as amine, dimethylethanolamine, diethylethanolamine, morpholine, N-methylmorpholine and 2-amino-2-ethyl-1-propanol; alkali metals such as lithium, potassium and sodium; sodium hydroxide; Inorganic alkalis of potassium and the like can be mentioned, but in order to improve weather resistance and water resistance after drying, those having high volatility which easily dissociates by heat are preferable, and ammonia, trimethylamine and triethylamine are preferable. Good. These neutralizing agents may be used alone or in combination of two or more.

The neutralizing agent (D) forms a salt with the carboxylic acid introduced into the polyurethane polymer. The amount of the carboxylate to be introduced is 0.05 to 1.5 mmol / g in the polyurethane-based polymer.
0.1 to 1.3 mmol / g. If the amount of the carboxylate is less than the lower limit, the polyurethane polymer does not disperse well in water. If it exceeds the upper limit, the water resistance of the dried polyurethane-based polymer will be insufficient. The pH of the emulsion is preferably from 7.5 to 10.5, and from 8 to 1
0 is more preferred. When the pH is lower than 7.5, the water-dispersibility of the polyurethane polymer becomes insufficient. Also, p
If H exceeds 10.5, the polymer may undergo molecular breakage over time due to a hydrolysis reaction.

In the present invention, a carboxylic acid salt is introduced into the molecular chain as a hydrophilic group in the polyurethane polymer in order to have a water dispersing ability.
An anionic polar group other than a carboxylate such as a sulfonate, a phosphate, or a phosphonate may be introduced, a cationic polar group such as a quaternary ammonium salt, or a nonionic polar group such as an ether group.

In the present invention, when synthesizing the polyurethane polymer, other polyols such as polyester polyol and a reaction terminator can be used as necessary. Examples of the reaction terminator include monoalcohols and monoamines, and in some cases, amino alcohols can also be a reaction terminator. Further, monoisocyanates such as phenyl isocyanate, butyl isocyanate, cyclohexyl isocyanate and the like can also be used as a reaction terminator.

Specific examples of the monoalcohol include methanol, ethanol, propanol, isopropanol,
2-ethylhexanol and the like. Monoamines include primary amines such as ethylamine, propylamine and butylamine, and secondary amines such as diethylamine and dibutylamine.
There are secondary amines. Examples of the amino alcohol include monoethanolamine and diethanolamine.

The method for producing the polyurethane polymer used in the present invention includes a one-shot method in which the reaction is carried out in an atmosphere having an excess of active hydrogen, and a method in which an active hydrogen compound is reacted with an organic diisocyanate in an excess of an isocyanate group to form an isocyanate group-terminated prepolymer. A polymer can be synthesized and then synthesized by a known method such as a prepolymer method in which an active hydrogen compound, particularly a chain extender is reacted. Also, after reacting the polyurethane polymer in an organic solvent compatible with water,
It can also be obtained by adding water and then removing the organic solvent, or by synthesizing a polymer without using a solvent and forcibly dispersing or dissolving in water. The salt formation time between the carboxylic acid introduced into the polyurethane polymer and the (D) neutralizing agent may be before or after the urethane-forming reaction.

In the case of the one-shot method, the molar ratio of isocyanate groups / active hydrogen groups is from 0.5 to less than 1, preferably from 0.8 to less than 1. If less than 0.5,
Since the molecular weight of the polyurethane polymer is too small, durability is lacking. In the case of one or more, when synthesizing the polymer,
Gelation is likely to occur.

In the case of the prepolymer method, the molar ratio of isocyanate groups / active hydrogen groups at the time of prepolymer synthesis is 1.1.
To 5.0, preferably 1.5 to 4.0.
If it is less than 1.1, the molecular weight of the prepolymer becomes too large, making it difficult to proceed to the subsequent reaction step. 5.0
If it exceeds, the adhesion will be poor.

The total of the urethane group concentration and the urea group concentration of the polyurethane polymer used in the present invention is 1.0 to 1.0.
3.0 mmol / g, preferably 1.3 to 2.7 mmol
1 / g. When no urea group is present in the polymer, the urethane group concentration is 1.0 to 3.0 mmol /
g, preferably 1.3 to 2.7 mmol / g. If the sum of the urethane group concentration and the urea group concentration is less than the lower limit, the strength of the ink film tends to be insufficient. If the upper limit is exceeded, the adhesion of the ink film tends to be insufficient.

When an organic solvent is used, usable organic solvents include toluene, xylene, swazol (an aromatic hydrocarbon solvent manufactured by Cosmo Oil Co., Ltd.) and Solvesso (an aromatic hydrocarbon solvent manufactured by Exxon Chemical Co., Ltd.). Aromatic solvents such as hydrogen solvents), ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; alcohol solvents such as methanol, ethanol, and isopropanol; ester solvents such as ethyl acetate, butyl acetate, and isobutyl acetate; Glycol ether ester solvents such as ethylene glycol ethyl ether acetate, propylene glycol methyl ether acetate, 3-methyl-3-methoxybutyl acetate, and ethyl-3-ethoxypropionate; and ethers such as tetrahydrofuran and dioxane. Le-based solvents. One or more of the above solvents can be used.

As a reaction catalyst for synthesizing an isocyanate group-terminated prepolymer or a polyurethane polymer used in the present invention, a known so-called urethanization catalyst can be used. Specific examples include organic metal compounds such as dioctyltin dilaurate, organic amines such as triethylenediamine, and salts thereof. The reaction temperature during urethanization is 10 to 100 ° C, preferably 30 to 80 ° C.
It is.

The number average molecular weight of the polyurethane polymer thus obtained is preferably 5,000 or more,
In particular, it is preferably 10,000 or more. When the number average molecular weight of the polyurethane-based polymer is less than 5,000, durability becomes poor. In the present invention, the number average molecular weight of the polymer is measured by a gel permeation chromatography (GPC) method using a polystyrene calibration curve.

The polyurethane emulsion has an average particle size of 10 to 3,000 nm, preferably 20 to 2.8 nm.
00 nm. If the average particle size exceeds the upper limit, it cannot be present as an emulsion. The average particle size is a value obtained by analyzing a value measured by a dynamic light scattering method by a cumulant method.

The viscosity of the polyurethane emulsion at 25 ° C. is from 10 to 30,000 mPa · s, preferably from 20 to 25,000 mPa · s. If the viscosity exceeds the upper limit, it will be difficult to make ink or print.

The minimum film forming temperature (hereinafter abbreviated as MFT) of the polyurethane emulsion of the present invention is lower than 35 ° C., preferably 30 ° C. or lower. If the MFT is 35 ° C. or higher, the adhesion of the ink film tends to be insufficient. Further, when the drying step is insufficient, the ink film may be cracked. The MFT is a temperature at which the polymer particles of the emulsion are deformed from the particles into a film by capillary pressure. Attempts to form a film at a temperature lower than the MFT will result in a powder or a broken film. The method of measuring MFT in the present invention is described in "Souichi Muroi, Chemistry of Polymer Latex, Polymer Publishing Association (197
0)).

The strength at break of the polyurethane polymer of the present invention (in a tensile test at a measurement temperature of 25 ° C.)
Is preferably 1 to 120 MPa, more preferably 5 to 120 MPa.
110 MPa. The elongation is 100-1,500
%, More preferably 110 to 1,400%. When the strength at break exceeds the upper limit, and when the elongation at break is less than the lower limit, the adhesion of the ink film tends to be insufficient. In the opposite case, the durability of the ink film tends to be insufficient. The tensile speed in the tensile test is a value measured at 200 mm / min.

The glass transition temperature of the polyurethane polymer in the present invention is preferably -100 to 30 ° C, more preferably -80 to 20 ° C. When the glass transition temperature is lower than the lower limit, the strength of the ink film tends to be insufficient. If the ratio exceeds the upper limit, the adhesion tends to be insufficient. The glass transition temperature is the dynamic viscoelasticity E ″
It is measured as the temperature at which the (loss modulus) becomes maximum. The measurement conditions of the dynamic viscoelasticity are a temperature rising rate of 2 ° C./min and a frequency of 35 Hz.

In the polyurethane-based emulsion of the present invention, if necessary, additives and auxiliaries commonly used in aqueous systems can be used. For example, pigments, antiblocking agents, dispersion stabilizers, viscosity regulators, leveling agents, antigelling agents, light stabilizers, antioxidants, ultraviolet absorbers, inorganic and organic fillers, plasticizers, lubricants, antistatic agents , A reinforcing material, a catalyst and the like can be added.

The polyurethane emulsion of the present invention can be used by blending another resin emulsion. For example, an acrylic emulsion, a polyester emulsion, a polyolefin emulsion, a latex and the like are used.

The aqueous printing ink of the present invention comprises the above-mentioned polyurethane-based emulsion, coloring components such as pigments and dyes, and, if necessary, other resins, water for adjusting the solid content and viscosity, and adjusting the surface tension. Organic solvents such as isopropanol and N-methylpyrrolidone, antiblocking agents,
Consists of additives such as dispersion stabilizer, thixotropic agent, antioxidant, ultraviolet absorber, defoamer, thickener, dispersant, surfactant, catalyst, filler, lubricant, antistatic agent, plasticizer, etc. These are blended and obtained using a ball mill, a sand grind mill, or the like. Further, if necessary, a curing agent may be added and used immediately before application. Specific curing agents include polyisocyanate-based curing agents such as Aquanate 100 and 200 manufactured by Nippon Polyurethane Industry.

[0039]

According to the present invention, it has become possible to provide a water-based printing ink which has excellent adhesion and good workability during printing. The aqueous printing ink of the present invention is most suitable for an aqueous printing ink for back printing.

[0040]

EXAMPLES Next, examples of the present invention and comparative examples will be described in detail, but the present invention is not limited to these examples. Unless otherwise specified, “parts” and “%” in Examples are “parts by weight” and “% by weight”, respectively.
Means

[Synthesis of Polyurethane Emulsion] Example 1 A reactor equipped with a stirrer, a thermometer, a nitrogen sealed tube, and a condenser was equipped with 271 parts of acetone and 400 parts of polyol (1).
0 parts and 10.4 parts of NPG were charged and uniformly mixed at 40 ° C. Thereafter, 58.4 parts of IPDI and 0.072 parts of DBTDL were charged and reacted at 60 ° C. for 3 hours. In advance, 322 parts of acetone, 74.3 parts of DMBA, and T
A carboxylate solution consisting of 50.6 parts of EA was charged and further reacted at 60 ° C. for 2 hours to obtain an isocyanate group-terminated prepolymer solution. 148 parts of IPA was previously added to the isocyanate group-terminated prepolymer solution,
An amine solution consisting of 38.3 parts of IPDA and 3.1 parts of MEA was charged and allowed to undergo an amine extension reaction for 1 hour. After completion of the reaction, 1136 parts of water was charged and the phase was inverted, and then acetone and IPA were removed by a rotary evaporator.
A polyurethane emulsion P-1 was obtained. The solid content of P-1 is 40.0%, the viscosity is 330 cP (25 ° C.), the average particle size is 60 nm, the MFT is 0 ° C. or less, and the number average molecular weight is 3
It was 1,000.

Examples 2 to 9 and Comparative Examples 1 to 5 P-2 to P-2 were prepared in the same manner as in Example 1 with the formulations shown in Tables 1 and 2.
14 was synthesized. The synthesis results are shown in Tables 1 and 2.

[0043]

[Table 1]

[0044]

[Table 2]

Examples 1 to 9, Comparative Examples 1 to 5, Tables 1 and 2 Polyol (1): Polycarbonate polyol obtained from 1,6-hexanediol and diethyl carbonate Number average molecular weight = 2,000, Average number of functional groups = 2 Polyol (2): Poly (oxytetramethylene) polyol Average molecular weight = 2,000, average number of functional groups = 2 Polyol (3): Polycaprolactone polyol Number average molecular weight = 2,000, Average number of functional groups = 2 Polyol (4 ): Number average molecular weight obtained from polyol (1), diethylene glycol and adipic acid = 2
Polyester (PES) with polyester (PES) having an average number of functional groups = 2 Polyol (1) / PES = 8/2 (weight ratio) Average molecular weight = 2,000, Average number of functional groups = 2 Polyol (5): 3- Polyester polyol obtained from methyl-1,5-pentanediol and adipic acid Number average molecular weight = 3,000, average number of functional groups = 2 Polyol (6): Acid component is iPA / AZA = 5/5
(Molar ratio), the polyol component is EG / NPG = 1/9
(Molar ratio) Polyester polyol Number average molecular weight = 2,000, average functional group number = 2, iPA: isophthalic acid AZA: azelaic acid EG: ethylene glycol NPG: neopentyl glycol Polyol (7): 1,6-hexanediol Polycarbonate polyol obtained from styrene and diethyl carbonate Number average molecular weight = 1,000, average number of functional groups = 2 Polyol (8): Polyester polyol obtained from 1,6-hexanediol and adipic acid Number average molecular weight = 1,000, average functionality Number of groups = 2 Polyol (9): Poly (oxytetramethylene) polyol Average molecular weight = 1,000, Average number of functional groups = 2 NPG: Neopentyl glycol IPDI: Isophoronediamine H ₁₂ -MDI: Hydrogenated diphenylmethane diisocyanate Over preparative H ₆ -XDI: hydrogenated xylylene diisocyanate TDI: 2,4-toluene diisocyanate DBTDL: dibutyltin dilaurate DMPA: dimethylolpropionic acid DMBA: dimethylolbutanoic acid TEA: Triethylamine IPA: Isopropanol IPDA: isophorone diamine MEA: Mono Ethanolamine

Average particle size measuring device: Electrophoretic light scattering system ELS-800 MFT device manufactured by Otsuka Electronics Co., Ltd. Minimum film forming temperature measuring device manufactured by Takabayashi Rika Co., Ltd. Refrigerant: 35% aqueous solution of ethylene glycol Atmosphere: Dry air Medium Number average molecular weight measurement device: HLC-80 manufactured by Tosoh Corporation
20 columns: TSKgel G3000H and 4000H

P-1 to P-14 were cast and dried to form a dry film having a thickness of about 40 μm, and various physical properties were measured. Table 3 shows the measurement results. Drying conditions: 80 ° C x 20 hours

Physical property measurement items: Tensile test A sample was prepared by punching out using a No. 4 dumbbell of JIS K6301 (1995). Tensile property measuring device: Tensilon UTA-500 manufactured by Orientec Co., Ltd. Measurement conditions: Tensile speed = 200 mm / min, measuring temperature = 25
℃ Glass transition temperature The temperature at which E ″ in the dynamic viscoelasticity is a maximum is defined as the glass transition temperature. Dynamic viscoelasticity measuring device: Levivibron DDV-01FP manufactured by Orientec Co., Ltd. Measurement conditions: Heating rate = 2 ° C. / Min, frequency = 35Hz

[0049]

[Table 3]

[Inking Test] Examples 10 to 18 and Comparative Examples 6 to 10 Blue inks were prepared with the following formulations. Printing was performed on various substrates using these inks, and the ink performance of the printed samples was evaluated. Table 4 shows the evaluation results. (Ink formulation) Ink formulation Precise polyurethane emulsion (solid content conversion) 18 parts Phthalocyanine blue 12 parts Water (including water in the emulsion) 65 parts Isopropanol 5 parts The mixture of the above composition, glass beads in the dispersion medium and the mixture Using the same amount, the mixture was ground for 2 hours using a paint shaker. Next, Aquanate 10 was added to 100 parts of the meat product.
1.0 (self-emulsifying type polyisocyanate, manufactured by Nippon Polyurethane Industry) was charged and uniformly dispersed to prepare a blue aqueous printing ink. (Printing conditions) Ink: Blue ink prepared above Printing machine: Simple gravure printing machine equipped with a gravure plate Printing speed: 20 m / min Ink thickness: Ink thickness 1 μ (dry) Printing substrate: Corona-treated stretched polypropylene film ( 2
(0 μm thickness) Corona-treated stretched polyethylene terephthalate film (11 μm thickness) Corona discharge-treated nylon film (15 μ thickness) (Evaluation item) Adhesion After printing, let it stand overnight, then attach a cellophane tape to the printed surface, Peeled off. Evaluation A: 90% to 100% of the printed film remained. Good: 70% to 80% of the printed film remained. Δ: 50% to 70% of the printed film remained. X: Only 50% or less of the printed film remained. Appearance After printing, the sheet was allowed to stand overnight, and then the appearance of the printed surface was observed.

[0051]

[Table 4]

Claims (2)

[Claims] (A) a number average molecular weight of 500 to 10,000
A water-based emulsion of a polyurethane polymer obtained by reacting a polyol (B), (B) a chain extender, (C) a compound containing a carboxyl group and an active hydrogen group, (D) an organic polyisocyanate, and (E) a neutralizing agent. A polyurethane emulsion for aqueous printing ink, wherein the minimum film forming temperature of the aqueous emulsion is lower than 35 ° C. 2. An aqueous printing ink using the polyurethane emulsion according to claim 1.