JP2017002184A - Polyurethane urea resin solution and printing ink - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polyurethane urea resin solution excellent in viscosity stability while having reduced odor, capable of forming a coated film hardly deteriorating physical properties such as strength even under a wet heat condition and excellent in wet heat resistance and useful as a binder for a printing ink.SOLUTION: There is provided a polyurethane urea resin solution containing a polyester-based polyurethane urea resin having an active amino group at a terminal, an ester solvent, an alcohol solvent and acetone and having content of acetone of 0.1 to 10 molar equivalence based on amount of an active amino group.SELECTED DRAWING: None

Description

  The present invention relates to a polyurethane urea resin solution useful as a binder for printing ink and a printing ink using the same.

  A printing ink using a polyester-based polyurethane urea resin solution as a binder for printing ink is useful in that it has excellent pigment dispersibility and exhibits excellent adhesion performance to various plastic substrates. In recent years, printing inks that do not contain toluene or methyl ethyl ketone (MEK), which are considered problematic in terms of odor, have been used from the viewpoint of addressing environmental problems. Specifically, a so-called non-toluene non-MEK printing ink mainly composed of an ester solvent or an alcohol solvent is used.

  As the polyester-based polyurethane urea resin used as a binder for printing ink, a polyurethane urea resin having an active amino group at the terminal is useful from the viewpoint of pigment dispersibility and adhesion performance to various plastic substrates. However, a solution containing a polyurethane urea resin having an active amino group at the terminal and an organic solvent mainly composed of an ester solvent or an alcohol solvent has a problem that the viscosity tends to decrease with time. In addition, this solution has a problem that the molecular weight of the polyurethane urea resin contained in the solution tends to decrease, and the physical properties of the resin also easily change. And the printing ink which used this solution as a binder also had the subject that a printability changed easily while a viscosity fell with time.

  In order to prevent a decrease in viscosity over time of a solution containing a polyurethane urea resin having an active amino group at the terminal and an organic solvent mainly composed of an ester solvent or an alcohol solvent, for example, a binder containing a hydroxycarboxylic acid Etc. have been proposed (Patent Documents 1 and 2).

JP 2003-221539 A JP 2008-56782 A

  However, as a result of the study by the present inventors, it has been found that the film formed using the binder proposed in Patent Documents 1 and 2 is likely to deteriorate under wet heat conditions. In addition, it was found that an ink film formed using a printing ink containing the above-described binder or the like is likely to deteriorate under wet heat conditions, similarly to a film formed using a binder or the like.

  The present invention has been made in view of such problems of the prior art, and the problem is that the odor is reduced, the viscosity stability is excellent, and the heat and humidity conditions are satisfied. However, it is an object of the present invention to provide a polyurethane urea resin solution useful as a binder for printing inks, which can form a film excellent in moisture and heat resistance in which physical properties such as strength are not easily deteriorated. Moreover, the place made into the subject of this invention is providing the printing ink which used said polyurethane urea resin solution as a binder.

That is, according to the present invention, the following polyurethane urea resin solution is provided.
[1] A polyester-based polyurethane urea resin having an active amino group at the terminal, an ester solvent, an alcohol solvent, and acetone. The content of the acetone is 0. 0 relative to the amount of the active amino group. A polyurethane urea resin solution having 1 to 10 molar equivalents.
[2] The polyurethane urea resin solution according to [1], wherein the ester solvent is ethyl acetate and the alcohol solvent is isopropyl alcohol.
[3] The polyurethane urea resin solution according to [1] or [2], wherein the amount of the active amino group per 1 g of the solid content of the polyurethane urea resin is 15 to 100 μg equivalent.

Moreover, according to this invention, the printing ink shown below is provided.
[4] A printing ink containing a binder for printing ink and a pigment, wherein the binder is the polyurethane urea resin solution according to any one of [1] to [3].

  According to the present invention, it is possible to form a film that has reduced odor, is excellent in viscosity stability, and has excellent moisture and heat resistance, such that the physical properties such as strength are not easily deteriorated even under wet heat conditions. A possible polyurethane urea resin solution useful as a binder for printing inks can be provided. Moreover, according to this invention, the printing ink which used said polyurethane urea resin solution as a binder can be provided.

<Polyurethane urea resin solution>
Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments.

  The polyurethane urea resin solution of the present invention contains a polyester polyurethane urea resin having an active amino group at the terminal, an ester solvent, an alcohol solvent, and acetone. And content of acetone in a polyurethane urea resin solution is 0.1-10 molar equivalent with respect to the quantity of the active amino group of a polyurethane urea resin. The details will be described below.

  The reason why the viscosity of a solution containing a polyester-based polyurethane urea resin having an active amino group at the terminal and an organic solvent mainly composed of an ester solvent or an alcohol solvent decreases with time is as follows. I guess that. That is, the transesterification decomposition of the polyurethane urea resin by the alcohol solvent is promoted by the active amino group. And it is thought that hydrolysis of a polyurethane urea resin is further accelerated | stimulated by the trace amount water | moisture content which exists in a resin solution.

  The present inventors have found that the polyurethane urea resin is less likely to be deteriorated even under wet heat conditions by blending acetone so as to have the above predetermined ratio with respect to the amount of active amino groups of the polyurethane urea resin. Moreover, an odor can also be reduced by containing acetone, without substantially containing organic solvents, such as toluene and MEK. That is, acetone is considered to be a component that functions as a viscosity stabilizer that stabilizes the viscosity of a solution containing a polyester-based polyurethane urea resin having an active amino group at the terminal.

  By blending acetone so as to have the above-mentioned predetermined ratio with respect to the amount of the active amino group, the active amino group is masked with acetone by the ketimination reaction. Thereby, it is presumed that the decrease in viscosity over time due to the decomposition of the resin is suppressed. In addition, since said ketimination reaction is reversible, acetone scatters with another solvent at the time of drying of printing ink. For this reason, the polyurethane urea resin solution of the present invention in which the blending amount of acetone is within the above range, and the printing ink using the same are excellent in terms of odor.

  Compared with MEK, which is conventionally used in many commercially available printing inks, acetone has a lower influence on the human body even if it is the same ketone solvent. Furthermore, acetone is not designated as an air pollutant represented by the Hazardous Air Pollutant (HAPS) regulations. For this reason, the polyurethane urea resin solution of the present invention containing acetone instead of MEK has a reduced burden on the environment.

(Polyurethane urea resin)
The polyurethane urea resin may be any resin as long as it is a polyester-based polyurethane urea resin having an active amino group at the terminal and is used as a binder for printing ink. In the present specification, the “active amino group” means a primary amino group and a secondary amino group having active hydrogen. The polyurethane urea resin as described above can be produced, for example, as shown below. First, a polymer diol containing a polyester polyol is reacted with an organic diisocyanate to obtain a urethane prepolymer having isocyanate groups at both ends. Next, an excess amount of diamine is allowed to act on the isocyanate group of the obtained urethane prepolymer to cause a chain extension reaction, whereby a polyester-based polyurethane urea resin having an active amino group at the terminal can be obtained.

  As the polyester polyol, a polyester polyol obtained by polycondensation of a polyvalent carboxylic acid and a polyhydric alcohol can be used. Specific examples of the polyvalent carboxylic acid include succinic acid, glutaric acid, adipic acid, sebacic acid, fumaric acid, maleic acid, terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid, tartaric acid, oxalic acid, malonic acid, pimelic acid, and suberin. Dibasic acids such as acid, glutaconic acid, azelaic acid, 1,4-cyclohexyldicarboxylic acid, α-hydromuconic acid, β-hydromuconic acid, α-butyl-α-ethylglutaric acid, α, β-diethylsuccinic acid And anhydrides thereof.

  Specific examples of the polyhydric alcohol include ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, 1,2-propanediol, 1,3-propanediol, and 2-methyl-1,3-propanediol. 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1,8 Aliphatic glycols such as octanediol, 1,9-nonanediol, neopentyl glycol; alicyclic glycols such as bishydroxymethylcyclohexane and cyclohexane-1,4-diol; aromatic glycols such as xylylene glycol; carbon number 1-18 alkyldiethanos Glycols such as alkyl dialkanolamines, such as amine.

  Specific examples of the polyester polyol include polyethylene adipate, polybutylene adipate, polyhexamethylene adipate, poly-2-methyl-1,3-propanediol adipate, poly-3-methyl-1,5-pentanediol adipate, polyneopentyl glycol Condensed polyester polyols such as adipate; lactone polyester diols such as polylactone diols, polycaprolactone diols and polymethylvalerolactone diols obtained by ring-opening polymerization of lactones using the above diols as initiators be able to.

  The number average molecular weight of the polyester polyol is preferably 500 to 6,000. If the number average molecular weight of the polyester polyol is less than 500, the re-solubility of the resulting polyurethane urea resin in the solvent may be poor, and the high-speed printability of the printing ink may be reduced. On the other hand, if the number average molecular weight of the polyester polyol is more than 6,000, the resulting polyurethane urea resin may have poor heat resistance, and the blocking resistance during winding required for printing ink may be reduced. is there.

  As polymer diols other than polyester polyol, for example, polyoxyethylene glycol, polyoxypropylene glycol, polyoxyethylene polyoxypropylene glycol, polyoxytetrabutylene glycol, polycarbonate diol, polybutadiene diol and the like may be used in combination with polyester polyol. .

  Specific examples of the organic diisocyanate include hexamethylene diisocyanate, butane-1,4-diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, xylylene diisocyanate, m-tetramethyl. Aliphatic diisocyanates such as xylylene diisocyanate; isophorone diisocyanate, cyclohexane-1,4-diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, methylcyclohexane diisocyanate, 4, 4'-dicyclohexylmethane diisocyanate, isopropylidene dicyclohexyl-4,4'-diisocyanate, norvo Alicyclic diisocyanates such as nadiisocyanate; 1,5-naphthylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 4,4′-dibenzyl diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyl Mention may be made of aromatic diisocyanates such as diphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, hydrogenated xylylene diisocyanate, tetramethyl xylylene diisocyanate.

  In addition to the above organic diisocyanates, for example, modified products such as burette modified products, allophanate modified products, isocyanurate modified products, and carbodiimide modified products of the above organic diisocyanates; adducts obtained by reacting the above organic diisocyanates with polyols, etc. It can also be used. From the comprehensive viewpoints such as reactivity and physical properties, the organic diisocyanate is preferably isophorone diisocyanate, hexamethylene diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, tolylene diisocyanate, or 4,4'-diphenylmethane diisocyanate. These organic diisocyanates can be used alone or in combination of two or more.

  Aliphatic diamine, alicyclic diamine, and aromatic diamine can be used as the diamine. Specific examples of the diamine include ethylenediamine, propylenediamine, butylenediamine, hexamethylenediamine, isophoronediamine, cyclohexyldiamine, piperazine, 2-methylpiperazine, phenylenediamine, tolylenediamine, xylenediamine, 1,3-cyclohexyldiamine, 4 , 4'-diaminodicyclohexylamine, m-xylylenediamine, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylpropylenediamine, di-2-hydroxypropylethylenediamine, hydrogenated products thereof, And a mixture thereof.

  Moreover, monoamines can be used as a reaction terminator with diamine as needed. Specific examples of monoamines include mono-n-butylamine, di-n-butylamine, monoethanolamine, diethanolamine and the like.

  The amount of active amino groups per gram of solid content of the polyurethane urea resin is preferably 15 to 100 μg equivalent. When the amount of the active amino group is less than 15 μg equivalent per 1 g of the solid content of the polyurethane urea resin, the adhesion to the polypropylene film or the polyester film may be lowered. On the other hand, if the amount of active amino groups exceeds 100 μg equivalent per gram of solid content of the polyurethane urea resin, for example, the increase in viscosity of the blended liquid when using a two-component ink blended with an isocyanate curing agent becomes significant. Usage time may be shortened. The amount of the active amino group at the end of the polyurethane urea resin can be controlled, for example, by adjusting the blending ratio of the urethane prepolymer, the diamine as a chain extender, and the monoamine as a reaction terminator. .

(Organic solvent)
The polyurethane urea resin solution of the present invention contains an ester solvent, an alcohol solvent, and acetone as an organic solvent. Examples of the ester solvent include ethyl acetate, n-propyl acetate, isopropyl acetate, n-butyl acetate, and isobutyl acetate. Of these, ethyl acetate is preferred. The content of the ester solvent in the polyurethane urea resin solution is not particularly limited, but may be usually 20 to 95% by mass.

  Examples of alcohol solvents include methyl alcohol, ethyl alcohol, isopropyl alcohol, n-butyl alcohol, and tertiary butyl alcohol. Of these, isopropyl alcohol is preferred. The content of the alcohol-based solvent in the polyurethane urea resin solution is not particularly limited, but may be usually 5 to 60% by mass.

  The method for preparing the polyurethane urea resin solution of the present invention is not particularly limited. For example, after preparing a resin solution containing a polyester-based polyurethane urea resin having an active amino group at the terminal, an ester solvent and an alcohol solvent, the ratio is set to a predetermined ratio with respect to the amount of active amino groups. The polyurethane urea resin solution of the present invention can be obtained by adding and mixing acetone.

<Printing ink>
The printing ink of the present invention contains a binder and a pigment for printing ink. And the binder for printing ink is the above-mentioned polyurethane urea resin solution.

  The kind of pigment used for the printing ink of the present invention is not particularly limited. For example, any of conventionally known inorganic pigments and organic pigments can be used. In addition, although it does not specifically limit about content of the pigment in printing ink, Usually, what is necessary is just 5-50 mass%.

  The method for preparing the printing ink of the present invention is not particularly limited. For example, first, a polyurethane urea resin solution, a pigment, and an organic solvent for dilution such as an ester solvent or an alcohol solvent are mixed, and if necessary, a dispersant, an antiblocking agent, an antifoaming agent, a leveling agent, a cup A ring agent, a plasticizer, a slow-drying solvent for controlling drying, an ultraviolet absorber, an antioxidant and the like are added. Subsequently, if it disperse | distributes using a well-known various disperser, the printing ink of this invention can be obtained.

  The content of the binder in the printing ink of the present invention is not particularly limited, but the content of the polyurethane urea resin solution (however, as a solid content) may be usually 10 to 50% by mass. In addition, the printing ink of the present invention includes, as necessary, nitrified cotton, chlorinated polyethylene, chlorinated polypropylene, vinyl chloride-vinyl acetate copolymer resin, maleic acid resin, polyvinyl as long as the effects of the present invention are not impaired. Butyral resins, fiber-based resins, and the like can also be included.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified.

<Preparation of polyurethane urea resin solution (binder)>
Example 1
A polyester diol having a number average molecular weight of 3,000, which was obtained using adipic acid and neopentyl glycol / 1,4-butanediol = 7/3 (molar ratio), was prepared. 500 parts of this polyester diol and 66.5 parts of isophorone diisocyanate were placed in a reaction vessel. The reaction was carried out at 100 ° C. for 5 hours under a nitrogen stream to obtain a urethane prepolymer having an NCO group content of 1.87%. The obtained urethane prepolymer was dissolved in 188.8 parts of ethyl acetate to obtain a urethane prepolymer solution having a nonvolatile content of 75%. 23.5 parts of isophoronediamine, 981.2 parts of ethyl acetate, and 206.5 parts of isopropyl alcohol were placed in a separate reaction vessel. While stirring the contents, 755.4 parts of a urethane prepolymer solution was dropped and reacted at 40 ° C. for 1 hour. As a viscosity stabilizer, 0.29 parts of acetone (0.2 molar equivalent with respect to the amount of active amino groups at the end of the resin) was added, and a ketimine reaction was performed at 40 ° C. for 30 minutes. As a result, a polyurethane urea resin solution having a nonvolatile content of 30% and a viscosity of 1020 mPa · s (25 ° C.) was obtained. The amount of active amino groups per gram of solid content of the polyurethane urea resin was 42.7 μg equivalent.

(Example 2)
A polyester diol having a number average molecular weight of 3,000, which was obtained using adipic acid and neopentyl glycol / 1,4-butanediol = 7/3 (molar ratio), was prepared. 500 parts of this polyester diol and 66.5 parts of isophorone diisocyanate were placed in a reaction vessel. The reaction was carried out at 100 ° C. for 5 hours under a nitrogen stream to obtain a urethane prepolymer having an NCO group content of 1.87%. The obtained urethane prepolymer was dissolved in 188.8 parts of ethyl acetate to obtain a urethane prepolymer solution having a nonvolatile content of 75%. 23.5 parts of isophoronediamine, 968.3 parts of ethyl acetate, and 206.5 parts of isopropyl alcohol were placed in a separate reaction vessel. While stirring the contents, 755.4 parts of a urethane prepolymer solution was dropped and reacted at 40 ° C. for 1 hour. As a viscosity stabilizer, 13.1 parts of acetone (9 molar equivalents relative to the amount of active amino groups at the end of the resin) was added, and a ketimine reaction was performed at 40 ° C. for 30 minutes. As a result, a polyurethane urea resin solution having a nonvolatile content of 30% and a viscosity of 1010 mPa · s (25 ° C.) was obtained. The amount of active amino groups per gram of solid content of the polyurethane urea resin was 42.7 μg equivalent.

(Example 3)
A polyester diol having a number average molecular weight of 2,000, obtained by using adipic acid and 3-methyl-1,5-pentanediol / 1,4-butanediol = 8/2 (molar ratio) was prepared. 500 parts of this polyester diol and 88.6 parts of isophorone diisocyanate were placed in a reaction vessel. The reaction was carried out at 100 ° C. for 5 hours under a nitrogen stream to obtain a urethane prepolymer having an NCO group content of 2.03%. The obtained urethane prepolymer was dissolved in 196.2 parts of ethyl acetate to obtain a urethane prepolymer solution having a nonvolatile content of 75%. 25.4 parts of isophoronediamine, 1.8 parts of di-n-butylamine, 1023.7 parts of ethyl acetate, and 215.6 parts of isopropyl alcohol were placed in a separate reaction vessel. While stirring the contents, 785.0 parts of a urethane prepolymer solution was added dropwise and reacted at 40 ° C. for 1 hour. As a viscosity stabilizer, 1.7 parts of acetone (1 molar equivalent with respect to the amount of active amino groups at the end of the resin) was added, and a ketimine reaction was performed at 40 ° C. for 30 minutes. As a result, a polyurethane urea resin solution having a nonvolatile content of 30% and a viscosity of 1200 mPa · s (25 ° C.) was obtained. The amount of active amino groups per gram of solid content of the polyurethane urea resin was 46.1 μg equivalent.

Example 4
A polyester diol having a number average molecular weight of 3,000, obtained by using adipic acid and 2-methyl-1,3-butanediol / ethylene glycol = 7/3 (molar ratio) was prepared. 500 parts of this polyester diol and 62.8 parts of isophorone diisocyanate were placed in a reaction vessel. The reaction was performed at 100 ° C. for 5 hours under a nitrogen stream to obtain a urethane prepolymer having an NCO group content of 1.67%. The obtained urethane prepolymer was dissolved in 187.6 parts of ethyl acetate to obtain a urethane prepolymer solution having a nonvolatile content of 75%. 20.3 parts of isophoronediamine, 0.86 parts of di-n-butylamine, 969.4 parts of ethyl acetate, and 204.4 parts of isopropyl alcohol were placed in a separate reaction vessel. While stirring the contents, 750.5 parts of a urethane prepolymer solution was dropped and reacted at 40 ° C. for 1 hour. As a viscosity stabilizer, 1.3 parts of acetone (1 molar equivalent with respect to the amount of active amino groups at the end of the resin) was added, and a ketimine reaction was performed at 40 ° C. for 30 minutes. As a result, a polyurethane urea resin solution having a nonvolatile content of 30% and a viscosity of 1300 mPa · s (25 ° C.) was obtained. The amount of active amino groups per gram of solid content of the polyurethane urea resin was 38.2 μg equivalent.

(Comparative Example 1)
A polyester diol having a number average molecular weight of 3,000, which was obtained using adipic acid and neopentyl glycol / 1,4-butanediol = 7/3 (molar ratio), was prepared. 500 parts of this polyester diol and 66.5 parts of isophorone diisocyanate were placed in a reaction vessel. The reaction was carried out at 100 ° C. for 5 hours under a nitrogen stream to obtain a urethane prepolymer having an NCO group content of 1.87%. The obtained urethane prepolymer was dissolved in 188.8 parts of ethyl acetate to obtain a urethane prepolymer solution having a nonvolatile content of 75%. 23.5 parts of isophoronediamine, 981.5 parts of ethyl acetate, and 206.5 parts of isopropyl alcohol were placed in a separate reaction vessel. While stirring the contents, 755.4 parts of a urethane prepolymer solution was dropped and reacted at 40 ° C. for 1 hour. As a result, a polyurethane urea resin solution having a nonvolatile content of 30% and a viscosity of 1020 mPa · s (25 ° C.) was obtained. The amount of active amino groups per gram of solid content of the polyurethane urea resin was 42.7 μg equivalent.

(Comparative Example 2)
A polyester diol having a number average molecular weight of 3,000, which was obtained using adipic acid and neopentyl glycol / 1,4-butanediol = 7/3 (molar ratio), was prepared. 500 parts of this polyester diol and 66.5 parts of isophorone diisocyanate were placed in a reaction vessel. The reaction was carried out at 100 ° C. for 5 hours under a nitrogen stream to obtain a urethane prepolymer having an NCO group content of 1.87%. The obtained urethane prepolymer was dissolved in 188.8 parts of ethyl acetate to obtain a urethane prepolymer solution having a nonvolatile content of 75%. 23.5 parts of isophoronediamine, 981.4 parts of ethyl acetate, and 206.5 parts of isopropyl alcohol were placed in a separate reaction vessel. While stirring the contents, 755.4 parts of a urethane prepolymer solution was dropped and reacted at 40 ° C. for 1 hour. As a viscosity stabilizer, 0.073 parts of acetone (0.05 molar equivalent with respect to the amount of active amino groups at the end of the resin) was added, and a ketimine reaction was performed at 40 ° C. for 30 minutes. As a result, a polyurethane urea resin solution having a nonvolatile content of 30% and a viscosity of 1020 mPa · s (25 ° C.) was obtained. The amount of active amino groups per gram of solid content of the polyurethane urea resin was 42.7 μg equivalent.

(Comparative Example 3)
A polyester diol having a number average molecular weight of 3,000, which was obtained using adipic acid and neopentyl glycol / 1,4-butanediol = 7/3 (molar ratio), was prepared. 500 parts of this polyester diol and 66.5 parts of isophorone diisocyanate were placed in a reaction vessel. The reaction was carried out at 100 ° C. for 5 hours under a nitrogen stream to obtain a urethane prepolymer having an NCO group content of 1.87%. The obtained urethane prepolymer was dissolved in 188.8 parts of ethyl acetate to obtain a urethane prepolymer solution having a nonvolatile content of 75%. 23.5 parts of isophoronediamine, 952.2 parts of ethyl acetate, and 206.5 parts of isopropyl alcohol were placed in a separate reaction vessel. While stirring the contents, 755.4 parts of a urethane prepolymer solution was dropped and reacted at 40 ° C. for 1 hour. As a viscosity stabilizer, 29.3 parts of acetone (20 molar equivalents relative to the amount of active amino groups at the end of the resin) was added, and a ketimine reaction was performed at 40 ° C. for 30 minutes. As a result, a polyurethane urea resin solution having a nonvolatile content of 30% and a viscosity of 1010 mPa · s (25 ° C.) was obtained. The amount of active amino groups per gram of solid content of the polyurethane urea resin was 42.7 μg equivalent.

(Comparative Example 4)
A polyester diol having a number average molecular weight of 2,000, obtained by using adipic acid and 3-methyl-1,5-pentanediol / 1,4-butanediol = 8/2 (molar ratio) was prepared. 500 parts of this polyester diol and 88.6 parts of isophorone diisocyanate were placed in a reaction vessel. The reaction was carried out at 100 ° C. for 5 hours under a nitrogen stream to obtain a urethane prepolymer having an NCO group content of 2.03%. The obtained urethane prepolymer was dissolved in 196.2 parts of ethyl acetate to obtain a urethane prepolymer solution having a nonvolatile content of 75%. 25.4 parts of isophoronediamine, 1.8 parts of di-n-butylamine, 1026.2 parts of ethyl acetate, and 215.6 parts of isopropyl alcohol were placed in a separate reaction vessel. While stirring the contents, 785.0 parts of a urethane prepolymer solution was added dropwise and reacted at 40 ° C. for 1 hour. As a viscosity stabilizer, 2.1 parts of tartaric acid (1 molar equivalent relative to the amount of active amino groups at the resin terminal) was added. As a result, a polyurethane urea resin solution having a nonvolatile content of 30% and a viscosity of 1180 mPa · s (25 ° C.) was obtained. The amount of active amino groups per gram of solid content of the polyurethane urea resin was 46.1 μg equivalent.

<Evaluation of polyurethane urea resin solution>
(1) Viscosity stability over time The polyurethane urea resin solution was stored at 40 ° C. for 1 month. The viscosity at 25 ° C. before and after storage of the polyurethane urea resin solution was measured, and the viscosity retention rate (%) was calculated. And the time-dependent viscosity stability was evaluated according to the evaluation criteria shown below. The results are shown in Table 1.
[Evaluation criteria]
○: Viscosity retention 95% or more Δ: Viscosity retention 80% or more and less than 95% ×: Viscosity retention 80% or less

(2) Odor Polyurethane urea resin solution was applied to a PET film with a 40 μm slit coater. Then, the polyurethane urea resin solution (without addition of acetone) of Comparative Example 1 was used as a control product, and the odor was sensoryly evaluated according to the following evaluation criteria. The results are shown in Table 1.
[Evaluation criteria]
○: No significant difference compared to the control product △: Stimulating odor is felt compared to the control product ×: Strong odor compared to the control product

(3) Moisture and heat resistance After the polyurethane urea resin solution was applied onto the release paper, it was dried to produce a film on which a film having a thickness of 50 μm was formed. The produced film was left in an atmosphere of 70 ° C. and 95% RH for 2 weeks. Using a tensile tester, the breaking strength of the film before and after standing was measured at a tensile speed of 200 mm / min, and the breaking strength retention rate (%) was calculated. And the heat-and-moisture resistance was evaluated according to the evaluation criteria shown below. The results are shown in Table 1.
[Evaluation criteria]
○: Breaking strength retention 80% or more Δ: Breaking strength retention 60% or more and less than 80% ×: Breaking strength retention 60% or less

<Preparation of printing ink>
(Example 5)
White ink was obtained by mixing and kneading 35 parts of titanium oxide white, 40 parts of the polyurethane urea resin solution of Example 1, 10 parts of n-propyl acetate, and 15 parts of isopropyl alcohol. A mixed solvent of ethyl acetate / isopropyl alcohol (mass ratio = 50/50) was added to the obtained white ink to adjust the viscosity at # 3 Zahn cup for 18 seconds to obtain a printing ink.

(Examples 6-8 and Comparative Examples 5-8)
Each printing ink was obtained in the same manner as in Example 5 except that the polyurethane urea resin solutions of Examples 2 to 4 and Comparative Examples 1 to 4 were used in place of the polyurethane urea resin solution of Example 1. It was.

<Evaluation of printing ink>
(1) Viscosity stability with time The printing ink was stored at 40 ° C. for 1 month. The viscosity at 25 ° C. before and after storing the printing ink was measured, and the viscosity retention rate (%) was calculated. And the time-dependent viscosity stability was evaluated according to the evaluation criteria shown below. The results are shown in Table 2.
[Evaluation criteria]
○: Viscosity retention 95% or more Δ: Viscosity retention 80% or more and less than 95% ×: Viscosity retention 80% or less

(2) Odor Printing ink was applied to a PET film having a thickness of 100 μm using a coater having a 40 μm slit. Then, the printing ink of Comparative Example 5 (without addition of acetone) was used as a control, and the odor was evaluated sensorily according to the following evaluation criteria. The results are shown in Table 1.
[Evaluation criteria]
○: No significant difference compared to the control product △: Stimulating odor is felt compared to the control product ×: Strong odor compared to the control product

(3) Moisture and heat resistance A gravure printing machine equipped with a gravure plate having a plate depth of 35 μm was prepared. Using this printer, printing ink was applied twice to a 12 μm thick biaxially stretched PET film subjected to corona discharge treatment, and then dried at 50 ° C. to obtain a white printing film. The obtained white printing film was allowed to stand for 1 day, and then a wet heat test was performed in which it was exposed to an atmosphere of 70 ° C. and 95% RH for 2 weeks. Furthermore, the adhesiveness test shown below was done about the white printing film before and behind the wet heat test. And the state of the printing surface after peeling off a cellophane tape was observed visually, and the heat-and-moisture resistance was evaluated according to the evaluation criteria shown below. The results are shown in Table 2.
[Adhesion test]
Cellophane tape (trade name “Cello Tape (registered trademark) 24 mm”, manufactured by Nichiban Co., Ltd.) was attached to the printing surface of the white printing film, and then peeled off at an angle of 90 degrees.
[Evaluation criteria]
○: In the adhesion test after the wet heat test, the amount of ink remaining on the PET film (remaining ink amount) was 90% or more.
Δ: In the adhesion test after the wet heat test, the amount of ink remaining on the PET film (remaining ink amount) was 50% or more and less than 90%.
X: In the adhesion test after the wet heat test, the amount of ink remaining on the PET film (remaining ink amount) was less than 50%.

  The polyurethane urea resin solution of the present invention is useful as a binder for printing ink.

Claims (4)

Containing a polyester-based polyurethane urea resin having an active amino group at the end, an ester-based solvent, an alcohol-based solvent, and acetone;
The polyurethane urea resin solution whose content of the said acetone is 0.1-10 molar equivalent with respect to the quantity of the said active amino group. The ester solvent is ethyl acetate,
The polyurethane urea resin solution according to claim 1, wherein the alcohol solvent is isopropyl alcohol.   The polyurethane urea resin solution according to claim 1 or 2, wherein the amount of the active amino group per 1 g of the solid content of the polyurethane urea resin is 15 to 100 µg equivalent. A printing ink containing a binder and a pigment for printing ink,
Printing ink whose said binder is the polyurethane urea resin solution as described in any one of Claims 1-3.