TWI766124B - Water-based liquid ink and printed matter - Google Patents

Abstract

The subject of the present invention is to provide an aqueous liquid ink composition which has the basic properties (adhesion to substrates, anti-blocking, high printing density, etc.) as an aqueous liquid ink, and furthermore It has both high water resistance (boil retort) and solvent resistance. The solution of the present invention is to use an aqueous liquid ink, which comprises a colorant (A), a binder (B) with an acid group, an alkaline compound (C) and an aqueous medium (D), and a binder with an acid group (B) comprising urethane resin (B1), urethane resin (B1) is a reaction product of polyol (b1) and polyisocyanate (b2), polyol (b1) comprising a polyvalent alcohol having an acid group At least one of the alcohol (b1-1), the polyester polyol (b1-2), and the polycarbonate polyol (b1-3), and the content of the alicyclic structure in the urethane resin (B1) is 1,000 mmol/kg or more, the basic compound (C) contains at least one of the basic metal compound (C1) and the organic amine (C2).

Description

Water-based liquid ink and printed matter

The present invention relates to aqueous liquid inks that can be used for aqueous printing and to prints printed using aqueous liquid inks.

Gravure printing and flexographic printing are widely used for the purpose of imparting decoration and functionality to to-be-printed objects. In recent years, in the printing ink industry, as a means to solve the problems of public hazards such as air pollution caused by solvent-based printing ink, occupational safety and health such as organic solvent poisoning, and even fire and explosion hazards The demand for water-based printing inks is increasing from the standpoint of safety and hygiene, environmental protection, and reduction of residual solvents in packaging materials. In fact, water-based printing inks are gradually being widely used in the printing of general packaging paper, corrugated paper and other paper containers.

As an example of such a water-based printing ink, there is proposed a surface-printing water-based ink for packaging, which is obtained by reacting a polyhydrazide compound and a polyamine compound other than the polyhydrazide compound with an isocyanate group-containing polymer. The organic solvent solution of the polyurethane resin is neutralized with deionized water containing ammonia water, whereby the water-solubilized water-based polyurethane resin is used as a binder (for example, refer to Patent Document 1: Japanese Patent Application Laid-Open No. 8-53641).

Furthermore, there is proposed a laminate water-based printing ink composition using a water-based polyurethane resin in which an organic diisocyanate compound, a specific polycarbonate diol containing a After the polymer diol compound and the chain extender are reacted and obtained, water and trimethylamine are added to make them water-based (for example, refer to Patent Document 2: Japanese Patent Laid-Open No. 5-171091).

prior art literature Patent Literature

Patent Document 1 Japanese Patent Application Laid-Open No. 8-53641

Patent Document 2 Japanese Patent Application Laid-Open No. 5-171091

However, if compared with solvent-based inks, water-based printing inks dry more slowly, in addition to having the basic properties of adhesion to plastic substrates and anti-blocking (anti-blocking), it must also have pigment dispersion. It is difficult to increase the printing density on the basis of both the properties and the like. For example, the water-based ink composition for packaging surface printing described in Patent Document 1 and the laminate water-based printing ink composition described in Patent Document 2 may have insufficient basic performance as an aqueous liquid ink. Moreover, the laminated water-based printing ink composition described in Patent Document 2 cannot be said to be able to withstand long-term printing in particular.

The present invention has been made in view of the foregoing, and its object is to provide an aqueous liquid ink that has both basic properties (adhesion to substrates, anti-sticking properties, high printing density, etc.) as well as high water resistance. (boil retort property) and solvent-resistant water-based liquid ink composition. By having the above-mentioned properties, it is possible to provide a printed matter that is resistant to boiling and high temperature sterilization even when it is used as an aqueous liquid ink (especially, an aqueous liquid ink for lamination printing of packaging materials).

The inventors of the present invention have made intensive studies to solve the above-mentioned problems, and as a result, have found that by using a binder for aqueous flexographic printing inks containing a urethane resin, the urethane resin contains an alkali metal. The basic compound of a compound and an organic amine neutralizes the urethane resin which the acid group which the urethane resin has, can solve the said subject, and completed this invention.

That is, the present invention relates to an aqueous liquid ink, which is an aqueous liquid ink comprising a colorant (A), a binder (B) having an acid group, an alkaline compound (C) and an aqueous medium (D), It is characterized in that: the aforementioned binder (B) having an acid group comprises a urethane resin (B1) which is a reaction product of a polyol (b1) and a polyisocyanate (b2), and the polyol (b1) comprises A polyol (b1-1) having an acid group and at least one selected from the group consisting of a polyester polyol (b1-2) and a polycarbonate polyol (b1-3), in the aforementioned urethane resin In the total amount of (B1), the content of the alicyclic structure contained in the urethane resin (B1) is 1,000 mmol/kg or more, and the basic compound (C) is selected from the group consisting of basic metal compounds ( At least one of the group of C1) and organic amine (C2).

According to the present invention, an aqueous liquid ink can be provided, which not only has the basic properties as an aqueous liquid ink (adhesion, anti-adhesion, high printing density, etc.), but also has high water resistance (boiling and high temperature sterilization) and High solvent resistance.

Form for carrying out the invention

The aqueous liquid ink of the present invention comprises a colorant (A), a binder (B) having an acid group, a basic compound (C) and an aqueous medium (D).

As the colorant (A), one type or two or more types can be used, and examples thereof include pigments such as organic pigments and inorganic pigments, dyes, and the like, and those that can be used for printing inks, paints, and recording agents are preferred.

系、異吲哚啉酮系、喹啉黃系、甲亞胺偶氮系、吡咯并吡咯二酮(diketopyrrolopyrrole)系、異吲哚啉系等顏料。 Examples of the organic pigments include azo-based, phthalocyanin-based, anthraquinone-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based,

series, isoindolinone series, quinoline yellow series, azomethine series, diketopyrrolopyrrole series, isoindoline series and other pigments.

Examples of the inorganic pigments include carbon black, titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, red red, aluminum, mica, and the like. In addition, based on the use of glass flakes or bulk flakes as a base material, a glittering pigment (METASHINE; Nippon Sheet Glass Co., Ltd.) coated with a metal or a metal oxide can be used.

As color index names, C.I. Pigment Yellow 1, 3, 12, 13, 14, 17, 42, 74, 83; C.I. Pigment Orange 16; C.I. Pigment Red 5, 22, 38, 48:1, 48:2, 48:4, 49:1, 53:1, 57:1, 63:1, 81, 101; C.I.Pigment Violet 19, 23; C.I.Pigment Blue 23, 15:1, 15:3, 15:4, 17: 1, 18, 27, 29 C.I. Pigment Green 7, 36, 58, 59; C.I. Pigment Black 7; C.I. Pigment White 4, 6, 18, etc.

For blue printing ink, C.I. Pigment Blue 15:3 (copper phthalocyanin) is preferably used; for yellow printing ink, C.I. Pigment Yellow 83 is preferably used from the viewpoint of cost and light resistance; For red ink, it is preferable to use C.I. Pigment Red 57:1. From the point of view of cost and tinting strength, titanium oxide is preferably used for white printing ink; carbon black is preferably used for black printing ink; and gold and silver printing ink is preferably used. Aluminum is used; for pearl ink, mica is preferably used. Although aluminum is in the form of powder or paste, from the viewpoint of handling and safety, it is preferable to use paste, and whether to use leafing or no-leafing depends on the brightness and The point of concentration is appropriately selected.

The total content of the above-mentioned pigments is preferably 1 mass % or more and preferably 50 mass % or less in the total amount of the printing ink from the viewpoint of securing the density and tinting strength of the printing ink.

The aforementioned binder (B) having an acid group comprises a urethane resin (B1) which is a reaction product of a polyol (b1) and a polyisocyanate (b2), the polyol (b1) comprising a polyol having an acid group (b1-1) and at least one selected from the group consisting of polyether polyol (b1-2) and polycarbonate polyol (b1-3).

The acid value of the urethane resin (B1) is preferably 3 mgKOH/g or more, more preferably 5 mgKOH/g or more, and preferably 40 mgKOH/g or less, more preferably 30 mgKOH/g or less. In this specification, the acid value means calculated based on the usage amount of acid group-containing compounds such as polyol (b1-1) having an acid group used in the production of the aforementioned urethane resin (B1). theoretical value.

基骨架、異莰基骨架、二環戊基骨架、金剛烷基骨架等碳原子5以上20以下(較佳為碳原子數7以上12以下)的飽和的橋聯環結構等。此等之中，較佳為飽和的單環結構，更佳為環己環結構。 Moreover, the said urethane resin (B1) contains an alicyclic structure. By including the alicyclic structure, blocking of the printed matter can be suppressed. Examples of the alicyclic structure include, for example, cyclobutane, cyclopentane, cyclohexyl, cycloheptyl, cyclooctane, propylcyclohexyl and the like having 3 to 10 carbon atoms (preferably the number of carbon atoms). 4 or more and 8 or less) saturated monocyclic structure; tricyclo[5.2.1.0 ^2,6 ]decyl skeleton, bicyclo[4.3.0]nonyl skeleton, tricyclo[5.3.1.1]dodecyl skeleton, propyl group Tricyclic [5.3.1.1] dodecyl skeleton, drop

Saturated bridged ring structures of 5 to 20 carbon atoms (preferably 7 to 12 or less of carbon atoms) such as a base skeleton, an isocamphenyl skeleton, a dicyclopentyl skeleton, and an adamantyl skeleton, etc. Among these, a saturated monocyclic structure is preferable, and a cyclohexane ring structure is more preferable.

In the total amount of the aforementioned urethane resin (B1), the content of the alicyclic structure contained in the aforementioned urethane resin (B1) is 1,000 mmol/kg or more, preferably 1,200 mmol/kg or more, It is more preferably 1,500 mmol/kg or more, more preferably 5,000 mmol/kg or less, more preferably 3,000 mmol/kg or less, still more preferably 2,500 mmol/kg or less.

In this specification, the ratio of the alicyclic structure contained in the urethane resin (B1) is based on the polyol (b1), polyisocyanate ( The total mass of all raw materials such as b2), and the alicyclic structure-containing compound (polyol (b1-3) having an alicyclic structure, having an alicyclic structure) used in the production of the urethane resin (A) described above The calculated value of the material amount of the alicyclic structure possessed by the polyisocyanate).

Moreover, the said urethane resin (B1) may contain an aromatic ring. In the case where the aforementioned urethane resin (B1) contains an aromatic ring, in the total amount of the aforementioned urethane resin (B1), its content is preferably 0 mmol/kg or more, more preferably 500 mmol/kg or more, It is more preferably 1,000 mmol/kg or more, more preferably 4,000 mmol/kg or less, more preferably 3,000 mmol/kg or less, and still more preferably 2,500 mmol/kg or less.

The said alicyclic structure may be contained in the said polyol (b1), and may be contained in the said polyisocyanate (b2). The content ratio of the alicyclic structure derived from the polyisocyanate (b2) to the alicyclic structure derived from the polyol (b1) is, on a molar basis, 0 or more, preferably 0.05 or more, more preferably 0.1 More preferably, it is 0.2 or more, more preferably 10 or less, more preferably 8 or less, and still more preferably 5 or less.

Examples of the acid group of the polyol (b1-1) having an acid group include a carboxyl group or a sulfonic acid group, and examples of the polyol (b1-1) having an acid group include a polyol having a carboxyl group. , polyols with sulfonic acid groups, etc.

As the polyol having the aforementioned carboxyl group, one type or two or more types can be used, and examples thereof include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, and 2,2-dimethylolpropionic acid. Hydroxy acids such as oxalic acid; polyester polyols with carboxyl groups, etc. The polyester polyol having the aforementioned carboxyl group can be obtained by reacting the aforementioned hydroxy acid with various polycarboxylic acids.

As the polyol having a sulfonic acid group, one type or two or more types can be used, and examples thereof include a dicarboxylic acid having a sulfonic acid group or a salt thereof, and a polyol having a low molecular weight (eg, a molecular weight of 100 or more and 1000 or less). The polyester polyol of the reaction product, etc. Examples of the dicarboxylic acid having a sulfonic acid group include 5-sulfoisophthalic acid, sulfonic acid terephthalic acid, 4-sulfonic acid phthalic acid, and 5-(4-sulfonic acid phenoxy group) ) isophthalic acid, etc. Examples of the low-molecular-weight polyols include alkane diols having 1 to 10 carbon atoms, such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,6-hexanediol, and neopentyl glycol; Polyether polyols with 2 to 10 carbon atoms, such as diethylene glycol, etc.

The number-average molecular weight of the aforementioned acid group-containing polyol (b1-1) is preferably 100 or more, more preferably 2,000 or less, and more preferably 1,000 or less.

In this specification, the number-average molecular weight and the weight-average molecular weight are expressed as polystyrene-equivalent values measured by a gel permeation chromatography (GPC) method.

Examples of the polyester polyol (b1-2) include polyester polyols obtained by esterification of low-molecular-weight polyols (for example, polyols having a molecular weight of 50 to 300) and polycarboxylic acids; Polyester polyols obtained by ring-opening polymerization of cyclic ester compounds such as caprolactone; these copolymerized polyester polyols, etc.

As said low-molecular-weight polyol, ethylene glycol, diethylene glycol, 1,2-propylene glycol, dipropylene glycol, neopentyl glycol, 2-butyl-2-ethyl-1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,4-cyclohexanediol, 1,6-hexanediol, cyclohexanediol Low molecular weight (for example, molecular weight 50 or more and 300 or less) polyol and the like such as methanol.

Examples of the polycarboxylic acid include aliphatic polycarboxylic acids such as succinic acid, adipic acid, sebacic acid, and dodecanedicarboxylic acid; terephthalic acid, isophthalic acid, phthalic acid, and naphthalenedicarboxylic acid. and other aromatic polycarboxylic acids; and anhydrides or ester-forming derivatives of the aforementioned aliphatic polycarboxylic acids and aromatic polycarboxylic acids, and the like.

The number average molecular weight of the polyester polyol (b1-2) is preferably 500 or more, more preferably 1,000 or more, more preferably 4,000 or less, more preferably 3,000 from the viewpoint of compatibility with pigments and the like the following.

As said polycarbonate polyol (b1-3), the reaction product of carbonate and a polyol; the reaction product of phosgene and a polyol, etc. are mentioned, for example.

As said carbonate, methyl carbonate, dimethyl carbonate, ethyl carbonate, diethyl carbonate, cyclic carbonate, diphenyl carbonate, etc. are mentioned, for example.

Examples of the carbonate and the polyol that can react with phosgene include the polyols exemplified as the low-molecular-weight polyols mentioned above; polyether polyols (polyethylene glycol, polypropylene glycol, etc.), polyester polyols (Polyhexamethylene adipic acid etc.) etc. high molecular weight polyol (weight average molecular weight 500 or more 5,000 or less) etc. Among them, aromatic ring-containing polyols are preferred.

The number average molecular weight of the aforementioned polycarbonate polyol (b1-3) is preferably 500 or more, more preferably 1,000 or more, and more preferably 4,000 or less, from the viewpoint of compatibility with pigments and the like 3,000 or less.

Moreover, in the said polyol (b1), it is preferable that the content rate of the polycarbonate polyol (b1-3) in the sum total of the polyester polyol (b1-2) and the polycarbonate polyol (b1-3) is 0 mass % or more, more preferably 10 mass % or more, still more preferably 20 mass % or more, and preferably 100 mass % or less, more preferably 90 mass % or less, still more preferably 80 mass % or less.

The aforementioned polyol (b1) preferably contains at least the polycarbonate polyol (b1-3). Among the polyols (b1), the content of the polycarbonate polyol (b1-3) is preferably 0 mass % or more, more preferably 5 mass % or more, still more preferably 10 mass % or more, and preferably 100 mass % or more. The mass % or less is more preferably 90 mass % or less, and still more preferably 80 mass % or less.

In the polyol (b1), the total content of the acid group-containing polyol (b1-1), the polyester polyol (b1-2), and the polycarbonate polyol (b1-3) is preferable It is 60 mass % or more, more preferably 75 mass % or more, more preferably 80 mass % or more, still more preferably 90 mass % or more, and may be 95 mass % or less.

The aforementioned polyol (b1) preferably contains a polyol (b1-4) having an alicyclic structure.

As the polyol (b1-4) having an alicyclic structure, one type or two or more types can be used, and examples thereof include cyclobutanediol, cyclopentanediol, 1,4-cyclohexanediol, and cycloheptanediol. , cyclooctanediol, butylcyclohexanediol, cyclohexanedimethanol, hydroxypropylcyclohexanol, dicyclohexanediol, hydrogenated bisphenol A, 1,3-adamantanediol, etc. Saturated diols with structures; unsaturated diols with alicyclic structures such as 1,1'-biscyclohexylene glycol; saturated triols with alicyclic structures such as cyclohexane triols. The number average molecular weight of the polyol (b1-4) having an alicyclic structure is preferably 100 or more and 500 or less.

In the case of using the polyol (b1-4) having an alicyclic structure, the content of the polyol (b1) in the total amount of the polyol (b1) is preferably 0% by mass or more, from the viewpoint of suppressing the sticking of printed matter. 5 mass % or more is preferable, and 40 mass % or less is preferable, 25 mass % or less is preferable, 20 mass % or less is more preferable, and 10 mass % or less is further more preferable.

In the polyol (b1), the aforementioned polyol (b1-1) having an acid group, the aforementioned polyester polyol (b1-2), the aforementioned polycarbonate polyol (b1-3), and the aforementioned polyol having an alicyclic structure The total content of the polyol (b1-4) is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more.

As said polyol (b1), another polyol (b1-5) may be contained. As said other polyol, polyether polyol, low molecular weight polyol (for example, molecular weight 50 or more and 300 or less), polyolefin polyol, etc. are mentioned.

As the polyether polyol (b1-2), for example, one or two or more kinds of compounds having two or more groups (-NH- or -OH) having an active hydrogen atom as a starter can be exemplified. Alkylene oxide addition polymerizer.

As said starter, ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, trimethylene glycol, 1,3-butanediol, 1,4-butanediol, 1,3-butanediol, Compounds having two hydroxyl groups such as 6-hexanediol and bisphenol A; compounds having three hydroxyl groups such as glycerin, tri(methylol)ethane, and trimethylolpropane, and the like.

Examples of the alkylene oxide include epoxide compounds such as ethylene oxide, propylene oxide, butylene oxide, styrene oxide, and epichlorohydrin; and tetrahydrofuran and the like having 4 or more carbon atoms (preferably carbon atoms). 4 to 6, particularly preferably a cyclic ether having a carbon number of 4).

The number average molecular weight of the polyether polyol is preferably 500 or more, more preferably 1,000 or more, and more preferably 4,000 or less, more preferably 3,000 or less, from the viewpoint of compatibility with pigments and the like.

In this specification, the number average molecular weight is set to represent a value measured by a gel permeation chromatography (GPC) method.

As the low-molecular-weight polyol, a polyol having a molecular weight of 50 or more and 300 or less can be used, and examples thereof include ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6- Aliphatic polyols having 2 to 6 carbon atoms, such as hexanediol, 3-methyl-1,5-pentanediol, diethylene glycol, dipropylene glycol, neopentyl glycol, and 1,3-butanediol ; 1,4-cyclohexanediol, cyclohexanedimethanol and other polyols containing alicyclic structures; bisphenol compounds such as bisphenol A, bisphenol F and other alkylene oxide adducts containing aromatic structures of polyols, etc.

As said polyolefin polyol, a polyisobutylene polyol, a hydrogenation (hydrogenation) polybutadiene polyol, a hydrogenation (hydrogenation) polyisoprene polyol, etc. are mentioned, for example.

In the polyol (b1), the content of the other polyols (b1-5) is preferably 50 mass % or less, more preferably 40 mass % or less, still more preferably 30 mass % or less, still more preferably 20 mass % % or less, particularly preferably 10% by mass or less.

As said polyisocyanate (b2), 1 type or 2 or more types can be used, for example, 4,4'- diphenylmethane diisocyanate, 2,4'- diphenylmethane diisocyanate, carbodiimide modified|denatured are mentioned, for example Diphenylmethane diisocyanate, crude diphenylmethane diisocyanate, phenylene diisocyanate, tolyl diisocyanate, naphthalene diisocyanate, stretched diisocyanate, tetramethyl stretched diisocyanate, etc. Aromatic polyisocyanates; aliphatic polyisocyanates such as hexamethylene diisocyanate and lysine diisocyanate; cyclohexane diisocyanate, hydrogenated stubble diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, etc. Alicyclic structure polyisocyanate, etc.

As said polyisocyanate (b2), it is preferable to contain the polyisocyanate which has an alicyclic structure. In the aforementioned polyisocyanate (b2), the content of the polyisocyanate having an alicyclic structure is preferably 50% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and more preferably 100% by mass the following.

The equivalent ratio of the isocyanate group of the polyisocyanate (b2) to the hydroxyl group contained in the polyol (b1) [isocyanate group/hydroxyl group], on a molar basis, is preferably 0.8 or more, more preferably 0.9 or more, and It is preferably 2.5 or less, more preferably 2.0 or less, still more preferably 1.5 or less.

When producing the aforementioned urethane resin (B1), a chain extender may be used as necessary.

As the chain extender, one type or two or more types can be used, and examples thereof include polyamines, hydrazine compounds, and other compounds having active hydrogen atoms.

、2,5-二甲基哌

、異佛酮二胺、4,4’-二環己基甲烷二胺、3,3’-二甲基-4,4’-二環己基甲烷二胺、1,4-環己烷二胺、N-乙基胺基乙基胺、N-甲基胺基丙基胺等二胺；N-羥甲基胺基乙基胺、N-羥乙基胺基乙基胺、N-羥丙基胺基丙基胺等具有羥基的二胺；二乙烯三胺、二丙烯三胺等三胺；三乙烯四胺等四胺等。此等之中，較佳為乙二胺。 As said polyamine, ethylene diamine, 1, 2- propane diamine, 1, 6- hexamethylene diamine, piperazine, for example, can be mentioned.

, 2,5-Dimethylpiperidine

, isophorone diamine, 4,4'-dicyclohexylmethanediamine, 3,3'-dimethyl-4,4'-dicyclohexylmethanediamine, 1,4-cyclohexanediamine, N-ethylaminoethylamine, N-methylaminopropylamine and other diamines; N-hydroxymethylaminoethylamine, N-hydroxyethylaminoethylamine, N-hydroxypropylamine Diamines having hydroxyl groups such as aminopropylamine; triamines such as diethylenetriamine and dipropylenetriamine; tetraamines such as triethylenetetramine and the like. Among these, ethylenediamine is preferable.

Examples of the hydrazine compound include hydrazine, N,N'-dimethylhydrazine, 1,6-hexamethylenedihydrazine, succinic acid dihydrazine, adipic acid dihydrazine, and glutaric acid dihydrazine. , dihydrazine sebacate, dihydrazine isophthalate, β-semi-carbazine propionate hydrazine, 3-semi-carbazine-propyl-hydrazine formate, hemi-carbazine-3-semi-carbazine A base-3,5,5-trimethylcyclohexane, etc.

Examples of the other compounds having active hydrogen described above include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,3-butanediol, and 1,4-butanediol. , hexamethylene glycol, sucrose, methylene glycol, glycerol, sorbitol and other glycols; bisphenol A, 4,4'-dihydroxybiphenyl, 4,4'-dihydroxydiphenyl ether, 4 , 4'-dihydroxydiphenyl, hydrogenated bisphenol A, hydroquinone and other phenols, water, etc.

As the chain extender, for example, when a polyamine is used, the equivalent ratio [amine group/isocyanate group] of an amine group and an isocyanate group contained in the polyamine is preferably 1.2 or less, more preferably 0.3 or more and 1 or less.

The weight average molecular weight of the urethane resin (A) is preferably 5,000 or more, more preferably 10,000 or more, still more preferably 20,000 or more, and preferably 500,000 or less, from the viewpoint of improving the durability of the printed matter, More preferably, it is 200,000 or less, and still more preferably 100,000 or less. By increasing the weight average molecular weight, not only the durability of the printed matter can be improved, but also sticking caused by poor drying can be suppressed. .

The said urethane resin (B1) can be manufactured by making the said polyol (b1) and the said polyisocyanate (b2) react, and further making a chain extender react as needed. When making the said polyol (b1) and the said polyisocyanate (b2) react, you may make an organic solvent coexist. The reaction temperature at the time of making the said polyol (b1) and the said polyisocyanate (b2) react, Preferably it is 50 degreeC or more and 150 degrees C or less.

烷等醚溶劑；乙酸乙酯、乙酸丁酯等酯溶劑；乙腈等腈溶劑；二甲基甲醯胺、N-甲基吡咯啶酮等醯胺溶劑等。 As the above-mentioned organic solvent, one kind or two or more kinds can be used, for example, ketone solvents such as acetone and methyl ethyl ketone;

ether solvents such as alkane; ester solvents such as ethyl acetate and butyl acetate; nitrile solvents such as acetonitrile; amide solvents such as dimethylformamide and N-methylpyrrolidone, etc.

In addition, in order to achieve safety and reduce the load on the environment, the organic solvent may be partially removed, for example, by distillation under reduced pressure during or after the production of the urethane resin (B1), for example. all.

In the aforementioned binder (B) having an acid group, the content of the aforementioned urethane resin (B1) is preferably 90% by mass or more, more preferably 95% by mass or more, still more preferably 99% by mass or more, Particularly preferred is 100% by mass.

The aforementioned binder (B) having an acid group may be dispersed in advance in an aqueous medium (D) to be described later. As a method of dispersing the urethane resin (B1) in the aqueous medium (D) (aqueous method), there can be mentioned the preparation of the aforementioned binder (B) having an acid group (the binder (B) preparation step) , mixing the obtained binder (B) with an acid group and at least a part of the basic compound (C) described later (neutralization step), and mixing the obtained mixture with the aforementioned aqueous medium (D) to prepare a dispersion ( dispersion step).

In the case of using a chain extender, the chain extender may be added in the aforementioned preparation step of the binder (B), or may be added after the aforementioned dispersion step.

The content rate of the binder (B) having an acid group is in the aforementioned dispersion liquid from the viewpoints of resolubility of aqueous ink, suppression of sticking of printed matter, improvement of printing density, and adhesion to substrates. , preferably 10 mass % or more, more preferably 20 mass % or more, and preferably 50 mass % or less, more preferably 40 mass % or less.

In the aforementioned water-based method, an emulsifier can also be used as required. In addition, when dissolving in water and dispersing in water, a machine such as a homogenizer may be used as necessary.

As the aforementioned emulsifier, for example, polyoxyethylene nonylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene styryl phenyl ether, polyoxyethylene sorbitan tetraoleate, polyoxyethylene poly Nonionic emulsifiers such as oxypropylene copolymers; fatty acid salts such as sodium oleate, alkyl sulfate ester salts, alkyl benzene sulfonates, alkyl sulfosuccinates, naphthalene sulfonates, polyoxyethylene alkyl Anionic emulsifiers such as sulfate, alkane sulfonic acid sodium salt, alkyl diphenyl ether sulfonic acid sodium salt; cationic emulsifiers such as alkyl amine salt, alkyl trimethyl ammonium salt, alkyl dimethyl benzyl ammonium salt Emulsifier, etc. Among them, from the viewpoint of storage stability, an anionic or nonionic emulsifier is preferred.

The aforementioned basic compound (C) includes at least one selected from the group consisting of a basic metal compound (C1) and an organic amine (C2).

Examples of the basic metal compound (C1) include metal hydroxides such as sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, and magnesium hydroxide; metal chlorides such as sodium chloride and potassium chloride; and sulfuric acid. Copper and other metal sulfates, etc.

啉等環狀胺等。 Examples of the organic amine (C2) include ammonia; primary amines such as monoethanolamine; tertiary amines such as triethylamine and diethylethanolamine;

Cyclic amines such as linoline, etc.

The aforementioned basic compound (C) preferably contains at least an organic amine (C2).

The ratio represented by the following formula is preferably 0.001 or more, more preferably 0.01 or more, still more preferably 0.05 or more, and 0.3 or less, preferably 0.25 or less, more preferably 0.2 or less, and still more preferably 0.15 or less. When the said ratio is in the said range, the boiling high temperature sterilization property becomes favorable.

Molar number of basic metal compound (C1)×valence of basic metal compound (C1)/{(molar number of organic amine (C2)×valence of organic amine (C2))+(basic metal compound (C1) molar number × valence of basic metal compound (C1))}

The above-mentioned basic metal compound (C1) and the above-mentioned organic amine (C2) can also form a salt with the acid group of the above-mentioned binder (B) having an acid group in the aqueous liquid ink. It becomes easy to improve water dispersibility by neutralizing the acid group of the said binder which has an acid group by the said basic compound (C1) and the said organic amine (C2).

The content of the basic compound (C) is preferably 0.01 part by mass or more, more preferably 0.05 part by mass or more, more preferably 0.1 part by mass or more, relative to 100 parts by mass of the aforementioned binder (B) having an acid group, And it is preferable that it is 10 mass parts or less, More preferably, it is 7 mass parts or less, More preferably, it is 4 mass parts or less.

Examples of the aqueous medium (D) include water; a hydrophilic organic solvent; a mixture of water and a hydrophilic organic solvent, etc. From the viewpoint of safety and burden on the environment, water, or water and hydrophilicity are preferred. A mixture of organic solvents.

As the above-mentioned hydrophilic organic solvent, one kind or two or more kinds can be used, preferably one mixed with water, for example, alcohol solvents such as methanol, ethanol, n-propanol and 2-propanol; acetone, methyl ethyl ketone and the like; Isotonic solvent; ethylene glycol, diethylene glycol, propylene glycol, polyalkylene glycol, glycerin and other polyol solvents; propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol mono-n-propyl ether, ethyl card ether solvents such as alcohol; amide solvents such as N-methyl-2-pyrrolidone, etc.

When the aforementioned aqueous medium (D) contains water and a hydrophilic organic solvent, in the aqueous medium (D), the content of water is preferably 80% by mass or more, more preferably 85% by mass or more, and more preferably 90% by mass It is more than 100 mass % or less, for example, and also allows it to be 95 mass % or less.

The aqueous liquid printing ink of the present invention may further contain an auxiliary agent. As the adjuvant, waxes such as paraffin-based wax, polyethylene-based wax, and carnauba wax for imparting friction resistance, sliding property, etc.; amide oleate, amide stearate, amide sinapic acid, etc. Fatty acid amide compounds; silicone-based and non-silicon-based defoamers for suppressing foaming during printing; dispersants, etc.

As said dispersing agent, a nonionic dispersing agent is preferable.

The acid value of the dispersant is preferably 30 mgKOH/g or less, more preferably 25 mgKOH/g or less, still more preferably 20 mgKOH/g or less, and, for example, 1 mgKOH/g or more, and may be 3 mgKOH/g or more.

The acid value of the dispersant is preferably smaller than the acid value of the binder (B) having an acid group. The difference between the acid value of the binder (B) having an acid group and the acid value of the dispersing agent is, for example, 1 mgKOH/g or more, more preferably 3 mgKOH/g or more, and preferably 30 mgKOH/g or less, more preferably 20mgKOH/g or less.

The content of the dispersant is preferably 40 parts by mass or more, more preferably 50 parts by mass or more, more preferably 60 parts by mass or more, and preferably 100 parts by mass or less, relative to 100 parts by mass of the colorant (A). , more preferably 80 parts by mass or less, still more preferably 75 parts by mass or less.

The content of the dispersant is preferably 10 parts by mass or more, more preferably 20 parts by mass or more, more preferably 30 parts by mass or more, relative to 100 parts by mass of the aforementioned binder (B) having an acid group, and preferably 100 parts by mass or less, more preferably 80 parts by mass or less, still more preferably 60 parts by mass or less.

The viscosity of the aforementioned water-based liquid ink, as a value measured at 25°C using Zahn Cup #4 manufactured by Zahn Co., is preferably 7 seconds or more, more preferably 10 seconds or more, and more It is preferably 25 seconds or less, more preferably 20 seconds or less.

If the viscosity is expressed in milliPascal seconds, at 25°C, it is preferably 70(mPa·s) or more, more preferably 100(mPa·s) or more, and preferably 350(mPa·s) or less, more preferably Preferably, it is 250 (mPa·s) or less.

The surface tension of the aforementioned aqueous liquid ink is preferably 25 mN/m or more, more preferably 33 mN/m or more, and preferably 50 mN/m or less, more preferably 43 mN/m or less. By appropriately increasing the surface tension of the printing ink, the wettability of the printing ink to the substrate can be maintained, and at the same time, dot bridges (dot bridges in which adjacent dots are connected to each other in halftone dots) can be suppressed. Dirt on the printing surface), by appropriately reducing the surface tension of the printing ink, the wettability of the printing ink to the substrate can be improved and shrinkage can be suppressed.

The water-based liquid ink of the present invention can use Eiger Mill, sand mill, Gamma Mill, attritor commonly used in the manufacture of gravure and flexographic printing inks ), etc. to manufacture.

When preparing the aqueous liquid ink of the present invention, from the viewpoint of uniformity, the coloring agent (A), at least a part of the binder (B) having an acid group, and the basic compound (C) may be mixed in advance. ), the aforementioned dispersant, and at least a portion of the aforementioned aqueous medium (D) are mixed to prepare a preliminary composition (kneaded base ink).

The aqueous liquid ink system of the present invention has excellent adhesion to various substrates, and can be used for printers on paper, synthetic paper, thermoplastic resin films, plastic products, steel plates, etc. Ink for gravure printing of gravure printing plates, or flexographic printing using flexographic printing plates made of resin plates, etc., on the other hand, exclude inks suitable for ejecting ink from inkjet nozzles without using a plate. Inkjet printer. That is, in the case of inkjet printing, the ink droplets ejected from the nozzles will directly adhere to the substrate to form a printed matter. On the contrary, the aqueous liquid printing ink of the present invention temporarily attaches and transfers the printing ink. After the printing plate or the pattern is printed, only the ink is reattached to the substrate, and it is dried as required to make a printed matter.

The film thickness of the printing ink formed by the gravure printing method and the flexographic printing method using the aqueous liquid ink of the present invention is, for example, 10 μm or less, or preferably 5 μm or less.

The base material can include polyamide resins such as nylon 6, nylon 66, and nylon 46; polyethylene terephthalate (PET), polyethylene naphthalate, polypropylene terephthalate Polyester resins such as polyester, polypropylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate; polyhydroxycarboxylic acids such as polylactic acid; poly(ethylene succinate), Biodegradable resins such as aliphatic polyester resins such as poly(butylene succinate); polyolefin resins such as PP and polyethylene; thermoplastic resins such as polyimide resins, polyarylate resins, or mixtures thereof A film or a laminate of these can be used, but among them, films made of polyester, polyamide, polyethylene, and polypropylene can be preferably used. These base films may be either unstretched or stretched, and the production method thereof is not limited. In addition, the thickness of the base film is not particularly limited, either, but generally, it should just be in the range of 1 to 500 μm.

Corona discharge treatment is preferably performed on the printed surface of the base film, and silica, alumina, and the like can also be deposited by vapor deposition.

[Example]

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.

(Synthesis Examples 1 to 10, Comparative Synthesis Examples 1 to 3: Preparation of Binders (1) to (13))

The polyol (b1) shown in Table 1 and the polyisocyanate (b2) shown in Table 1 were reacted in methyl ethyl ketone in a nitrogen-substituted vessel equipped with a thermometer, a nitrogen introduction tube, and a stirrer, Thereby, the organic solvent solution of the urethane prepolymer (binder which has an acid group) which has an isocyanate group at a molecular terminal is obtained.

Next, by adding the basic compound (C) shown in Table 1 or its aqueous solution, a part or all of the carboxyl groups of the urethane prepolymer were neutralized, and water and water shown in Table 1 were added. The aqueous solution of the chain extender was sufficiently stirred to obtain an aqueous dispersion of the urethane resin, followed by aging and solvent removal to obtain a binder (1) to ( 40% by mass of nonvolatile content). 13).

Table 1 shows the content of the alicyclic structure, the content of the aromatic ring, and the acid value in the aforementioned urethane resin in the obtained binders (1) to (13).

In Table 1, polyester polyol 1 represents an aliphatic polyester polyol ("L212AL" manufactured by Daicel Co., Ltd., number average molecular weight 1,250), and polyester polyol 2 represents an aromatic polyester polyol (ethylene glycol 13.1 Aromatic polyester reacted in the presence of 0.03 parts by mass of monobutyltin oxide, 22.0 parts by mass of neopentyl glycol, 18.5 parts by mass of terephthalic acid, 18.5 parts by mass of isophthalic acid, and 7.9 parts by mass of acrylic acid Polyol. Number average molecular weight 1,000), polycarbonate polyol 1 represents polycarbonate polyol ("ETERNACOLL UH-200" manufactured by Ube Industries Co., Ltd., number average molecular weight 2,000), polycarbonate polyol 2 represents polyol Carbonate polyol ("ETERNACOLL UH-100" manufactured by Ube Industries Co., Ltd., number average molecular weight 1,000), polyether polyol 1 represents polyethylene tetraethylene glycol (number average molecular weight 2,000).

Examples 1 to 10, Comparative Examples 1 to 3

The binders (1) to (13) obtained in the synthesis example and the comparative synthesis example were sufficiently stirred and mixed with the following compositions, respectively, and then kneaded with a bead mill to prepare a kneaded base ink. Next, 10 parts by mass of each of the binders (1) to (13) and 4 parts by mass of water were additionally mixed with the obtained kneaded base ink to prepare a water-based blue printing ink. Using a viscosity cup #4 (manufactured by Shihe Co., Ltd.), the viscosity of the obtained printing ink was adjusted with water so that the viscosity of the obtained printing ink was 16 seconds (25° C.), and the water-based solutions of Examples 1 to 10 and Comparative Examples 1 to 3 were used, respectively. Liquid ink.

In addition, in order to confirm the surface tension of the obtained aqueous liquid ink, the surface tension at 25 degreeC was measured. The surface tension was measured based on the Whileelmy method using an automatic surface tensiometer DY-300 manufactured by Kyowa Interface Science Co., Ltd.

[Mixed base ink blending]

[Total blended amount of aqueous liquid ink (blue) (excluding water for viscosity adjustment)]

The water-based liquid inks of the examples and comparative examples were treated with the corona-treated polyethylene terephthalate (PET) film (Toyo) as shown in Table 1 using a Flexoproof 100 test printer (manufactured by Testing Machines, Inc.). On the ESTER E5102 (thickness 12μm) and corona-treated polypropylene (OPP) biaxially stretched film (PYLEN P2161, manufactured by Toyobo Corporation, thickness 20μm), a solid line pattern of 240mm in length x 80mm in width was printed. A dryer dries to obtain a printed matter.

The obtained printed matter was evaluated for boiling and high temperature sterilization, solvent resistance, anti-sticking property, and substrate adhesion when each film was used, and the ink transfer property was confirmed by printing density.

[Evaluation item 1: Boiling high temperature sterilization (hot water resistance)]

On the ink surface of the aforementioned corona-treated polyethylene terephthalate (PET) film print, a urethane-based dry lamination adhesive DICDRY LX-500/KW-75 (manufactured by DIC) was coated with After coating and drying so that the film amount would be 3.5 g/m ² , aluminum foil (hereinafter, AL: Aluminum Foil C, 15 μm, manufactured by Toyo Aluminum Co., Ltd.) was laminated by a dry laminator (manufactured by DIC ENGINEERING) to obtain a 2-layer laminate 1. Next, an adhesive was applied to the AL of the laminate 1 in the same manner, and a non-stretch polypropylene film (hereinafter, R-CPP: ZK-75 50 μm manufactured by Toray Synthetic Film Co., Ltd.) was laminated, and aged at 40° C. for 5 days. , a 3-layer composite laminate 2 was obtained.

The obtained laminate 2 was made into a bag with a size of 120 mm×120 mm, and as the content, 70 g of imitation food containing vinegar, salad oil, and meat sauce blended at a weight ratio of 1:1:1 was filled and sealed. After the prepared bag was subjected to sterilization treatment by steam sterilization at 135° C. for 30 minutes, the degree of peeling of the ink film was evaluated in four stages.

⊚: No peeling at all.

○: There are very few small bubble-like peelings.

(triangle|delta): Some intermediate-size foam-like peeling exists.

×: There is peeling on the entire surface irrespective of the size.

[Evaluation item 2: Solvent resistance]

The printed matter obtained above was rubbed 10 times with a cotton swab impregnated with ethanol to evaluate the degree of disappearance of the printed characters. A commercially available laminate in which the expiration date was printed by an ink jet method was used as a comparison standard. In addition, the determination criteria are as follows.

⊚: The printed part did not disappear at all, and it was good.

○: 80% or more of the printed portion did not disappear, which was good.

△: 50% of the printed portion disappeared.

×: 100% of the printed portion disappeared.

[Evaluation item 3: Sticking resistance]

Cut the film into 4cm×4cm size and overlap it so that the printing surface of the printed matter contacts the non-printing surface, apply a load of 5Kgf/cm ² , and leave it at 40°C for 12 hours. The state of the transfer of ink to the non-printed surface (ink backprint) was visually determined based on the area ratio (%) of the ink backprint portion.

⊚: Transfer to the non-printing surface was not observed at all.

○: Although it is a small amount of less than 5%, the transfer due to the back printing of the ink is seen.

△: More than 5% to less than 20% of the transfer caused by the back printing of the ink can be seen.

×: 20% or more of the transfer due to the back printing of the ink was seen.

[Evaluation Item 4: Substrate Adhesion]

After leaving the printed matter for 1 day, stick cellophane tape (12mm width made by NICHIBAN) on the printed surface, and the residual rate of the printed film when one end of the cellophane tape is rapidly peeled off at a right angle to the printed surface is based on the area ratio, The appearance was visually judged.

⊚: The printed film was not peeled off at all.

○: More than 80% to less than 90% of the printed film remains on the film.

△: More than 50% to less than 80% of the printed film remains on the film.

×: Less than 50% of the printed film remained on the film.

[Evaluation item 5: Ink transferability]

The ink transfer property was evaluated using a SpectroEye densitometer manufactured by X-Rite Corporation for the solid concentration of the printed matter.

○: The blue density of the printed matter is 1.9 or more, and the flexographic printing suitability is good.

Δ: The blue density of the printed matter is 1.6 or more and less than 1.9, and the flexographic printing suitability is medium.

×: The blue density of the printed matter is less than 1.6, and the suitability for flexographic printing is poor.

By using the water-based liquid printing ink of the present invention, it can provide both the basic properties of the water-based liquid printing ink (adhesion to the substrate, anti-adhesion, high printing concentration, etc.) Bactericidal) and solvent-resistant aqueous liquid ink composition. By having both of the above-mentioned properties, it is possible to provide printed matter that is also resistant to boiling and high temperature sterilization.

Claims (5)

An aqueous liquid printing ink for flexographic printing or gravure printing, which is an aqueous liquid printing ink comprising a colorant (A), a binder (B) with an acid group, an alkaline compound (C) and an aqueous medium (D). The ink is characterized in that: the binder (B) having an acid group is composed of a urethane resin (B1), and the urethane resin (B1) is a polyol (b1) and a polyisocyanate (b2) ), the polyol (b1) comprises: a polyol (b1-1) having an acid group; selected from the group comprising polyester polyol (b1-2) and polycarbonate polyol (b1-3) At least one of the group; and the polyol (b1-4) having an alicyclic structure, and the polyol (b1-4) having an alicyclic structure is included in a range of 20% by mass or less in the total amount of the polyol (b1). ), the polyisocyanate (b2) contains a polyisocyanate having an alicyclic structure, and in the total amount of the urethane resin (B1), the alicyclic structure contained in the urethane resin (B1) The content is 1,000 mmol/kg or more and 5,000 mmol/kg or less, the basic compound (C) contains at least one selected from the group consisting of basic metal compounds (C1) and organic amines (C2), the polyester polyvalent The alcohol (b1-2) is a polyester polyol obtained by subjecting a polyol having a molecular weight of 50 to 300 to an esterification reaction with a polycarboxylic acid, a polyester polyol obtained by subjecting a cyclic ester compound to a ring-opening polymerization reaction, and those selected from the group of copolymerized polyester polyols, the polycarbonate polyol (b1-3) is selected from the group consisting of carbonate and polyol The one selected from the group of the reaction product of alcohol and the reaction product of phosgene and polyol, the viscosity of the aqueous liquid printing ink is more than 7 seconds and less than 25 seconds at 25°C using a viscosity cup (Zahn Cup) #4 . The aqueous liquid ink according to claim 1, wherein the acid value of the binder (B) having an acid group is 3 mgKOH/g or more and 40 mgKOH/g or less. As claimed in claim 2, the water-based liquid ink has a surface tension of 25 mN/m or more and 50 mN/m or less at 25°C. As claimed in claim 1, the water-based liquid ink has a surface tension of 25 mN/m or more and 50 mN/m or less at 25°C. A printed matter is characterized in that it is printed using the aqueous liquid ink according to any one of claims 1 to 4.