JP5087063B2 - Printing ink binder and printing ink - Google Patents

Description

  The present invention relates to a binder used for printing ink such as gravure ink. More specifically, the present invention relates to a binder for printing ink that can be suitably used for gravure printing of a packaging plastic film excellent in environmental conservation and excellent in boil resistance, retort resistance, printability and adhesiveness of printed matter.

  In recent years, various plastic films have been developed as packaging materials in accordance with diversification of packages and advancement of packaging technology. The binders of gravure printing inks used for these plastic films have conventionally been rosin-modified maleic acid resin, nitrified cotton, polyamide resin, chlorinated polypropylene, polyurethane resin, vinyl chloride-vinyl acetate copolymer resin, etc. While conversion to non-chlorine-based resins that do not generate dioxins has progressed due to demands for maintenance, polyurethane resins are used more frequently than polyamide resins in product packaging inks in terms of safety and low odor.

  In general, printing inks that use polyurethane resin as a binder have excellent adhesion to polyester and nylon films alone. However, when printing on polyethylene and polypropylene films, which are general-purpose films, In order to supplement the adhesiveness, a two-component reaction type ink in which a polyisocyanate compound is blended with the ink is used in order to supplement the adhesiveness. However, the two-component reactive ink has a disadvantage that there is a practical limitation in terms of pot life (pot life).

  For this reason, polyurethane resins that have good adhesion to various plastic films and that can be used as binders for one-component inks that do not need to contain a polyisocyanate compound have been studied. It has been improved.

  However, for example, when a one-component ink is used for printing a plastic film used as a packaging material that is subjected to a boil sterilization process, a retort sterilization process, etc. after packaging food, such a printed product has a boil resistance and a retort resistance. There is a problem that the sex is still inferior. Therefore, in the field where boil resistance, retort resistance and the like are required, the one-component ink is difficult to use, and the two-component reactive ink is still used.

  In addition, recently, many manufacturers are actively tackling environmental problems, and there is a movement to configure products using materials with excellent environmental conservation. For example, in printing ink, studies are underway not to select toluene as the organic solvent to be used, and water-based printing inks that use aqueous solvents instead of organic solvents are being actively studied. Is insufficient (see Patent Documents 1 and 2).

JP 2003-221539 A JP 2004-115670 A

  Under such circumstances, binders used in printing inks such as gravure inks are required to have higher boil resistance, retort resistance, printing suitability, and adhesiveness, etc., as well as environmental conservation on a global scale. There is a demand for the development of environmentally friendly products.

  Accordingly, the object of the present invention is to contribute to the reduction of greenhouse gases by incorporating carbon dioxide from the viewpoint of the global environment as well as being excellent in the boil resistance, retort resistance, printability, and adhesiveness of the printed matter. It is to provide printing ink binders as environmentally friendly products.

The above object is achieved by the present invention described below. That is, the present invention is a hydroxyl group having a number average molecular weight of 2,000 to 100,000, obtained by reacting an amine compound with a 5-membered cyclic carbonate compound obtained by reacting an epoxy compound and carbon dioxide. The main component is a polyhydroxy polyurethane resin having a value of 25 to 300 mgKOH / g, the epoxy compound is at least one of the compounds represented by the following formulas, and the amine compound is methylene diamine, ethylene diamine, trimethylene. Diamine, 1,3-diaminopropane, hexamethylenediamine, octamethylenediamine, phenylenediamine, 3,3′-dichloro-4,4′-diaminodiphenylmethane, 4,4′-methylenebis (phenylamine), 4,4 ′ -Diaminodiphenyl ether, 4,4'-diaminodiph Nylsulfone, metaxylylenediamine, paraxylylenediamine, 1,4-cyclohexanediamine, 4,4'-diaminocyclohexylmethane, 1,4'-diaminomethylcyclohexane, isophoronediamine, monoethanoldiamine, ethylaminoethanolamine, hydroxy ethylamino propylamine, and bis to provide a printing ink binders according to at least one der wherein Rukoto selected from the group consisting of (aminopropyl) piperazine.

In the above-described present invention, the polyhydroxy polyurethane resin, it contains a carbon dioxide partial 1-25 wt%; it to contain printing ink binder is still another resin. Further, according to the present invention, any one of the above printing ink binders and at least one of an alkyl titanate compound and a polyisocyanate compound capable of reacting with a hydroxyl group of the polyhydroxy polyurethane resin contained in the printing ink binder. And a printing ink characterized by containing an agent.

  According to the present invention, by using a polyhydroxypolyurethane resin as a binder for printing ink, the printed matter is excellent in boil resistance, retort resistance, printability, adhesion, and the like, and carbon dioxide is also used from the viewpoint of the global environment. Incorporation provides a printing ink binder as an environmentally friendly product by contributing to the reduction of greenhouse gases.

The infrared absorption spectrum of an epoxy compound (Epicoat 828). The infrared absorption spectrum of a 5-membered cyclic carbonate compound. GPC elution curve of a 5-membered cyclic carbonate compound. Mobile phase: THF, column: TSK-Gel GMHXL + G2000HXL + G3000HXL, detector: IR

  Next, the present invention will be described in more detail with reference to preferred embodiments. The printing ink binder of the present invention is characterized by comprising a polyhydroxy polyurethane resin derived from the reaction of a 5-membered cyclic carbonate compound and an amine compound.

  The 5-membered cyclic carbonate compound used in the present invention can be produced by reacting an epoxy compound and carbon dioxide as shown in the following [Formula-A]. More specifically, the epoxy compound is reacted with carbon dioxide in the presence or absence of an organic solvent and in the presence of a catalyst at a temperature of 40 ° C. to 150 ° C. under normal pressure or slightly increased pressure for 10 to 20 hours. Can be obtained.

［参考文献］
N.Kihara,T.Endo,J.Org.Chem.,1993,58,6198
N.Kihara,T.Endo,J.Polymer Sci.,PartA Polmer Chem.,1993,31(12),2765

[References]
N. Kihara, T. Endo, J. Org. Chem., 1993, 58, 6198
N. Kihara, T. Endo, J. Polymer Sci., Part A Polmer Chem., 1993, 31 (12), 2765

  Examples of the epoxy compound used in the present invention include the following compounds.

  The epoxy compounds listed above are preferable compounds used in the present invention, and the present invention is not limited to these exemplified compounds. Accordingly, not only the above-exemplified compounds but also any other compounds that are currently commercially available and can be easily obtained from the market can be used in the present invention.

  Examples of the catalyst used in the reaction between the epoxy compound and carbon dioxide include a base catalyst and a Lewis acid catalyst. Examples of the base catalyst include tertiary amines such as triethylamine, tributylamine, diazabicycloundecene, diazabicyclooctane, and pyridine, alkali metal salts such as lithium chloride, lithium bromide, lithium fluoride, and sodium chloride, and chloride. Alkaline earth metal salts such as calcium, quaternary ammonium salts such as tetrabutylammonium chloride, tetraethylammonium bromide, benzyltrimethylammonium chloride, carbonates such as potassium carbonate and sodium carbonate, zinc acetate, lead acetate, copper acetate, iron acetate And metal acetates such as calcium oxide, magnesium oxide and zinc oxide, and phosphonium salts such as tetrabutylphosphonium chloride.

  Examples of the Lewis acid catalyst include tin compounds such as tetrabutyltin, dibutyltin dilaurate, dibutyltin diacetate, and dibutyltin octoate.

  The amount of the catalyst is 0.1 to 50 parts by mass, preferably 0.3 to 20 parts by mass, per 50 parts by mass of the epoxy compound. When the amount used is less than 0.1 parts by mass, the effect as a catalyst is small, and when it exceeds 50 parts by mass, various performances of the final resin are lowered.

  Examples of the organic solvent that can be used in the reaction between the epoxy compound and carbon dioxide include dimethylformamide, dimethylsulfoxide, dimethylacetamide, N-methylpyrrolidone, N-ethylpyrrolidone, and tetrahydrofuran. These organic solvents and other poor solvents such as methyl ethyl ketone, xylene, toluene, tetrahydrofuran, diethyl ether, and cyclohexanone may be used in a mixed system.

  Next, the obtained 5-membered cyclic carbonate compound and amine compound are reacted in the presence of an organic solvent at a temperature of 20 ° C. to 150 ° C. as shown in the following [Formula-B] to be used in the present invention. A hydroxy polyurethane resin is obtained.

  As the amine compound used in the present invention, any of those conventionally used for producing a polyurethane resin can be used and is not particularly limited. For example, aliphatic diamines such as methylenediamine, ethylenediamine, trimethylenediamine, 1,3-diaminopropane, hexamethylenediamine, octamethylenediamine; phenylenediamine, 3,3′-dichloro-4,4′-diaminodiphenylmethane, 4 , 4′-methylenebis (phenylamine), 4,4′-diaminodiphenyl ether, 4,4′-diaminodiphenylsulfone, metaxylylenediamine, paraxylylenediamine, and the like; 1,4-cyclohexanediamine, 4 , 4'-diaminocyclohexylmethane, 1,4'-diaminomethylcyclohexane, isophoronediamine and other alicyclic diamines; monoethanoldiamine, ethylaminoethanolamine, hydroxyethylaminopropylamine Such as alkanol diamine and the like.

  The amine compounds listed above are preferable compounds used in the present invention, and the present invention is not limited to these exemplified compounds. Accordingly, not only the above-exemplified compounds but also any other compounds that are currently commercially available and can be easily obtained from the market can be used in the present invention.

  In addition, the number average molecular weight (measured by GPC and converted to standard polystyrene) of the polyhydroxy polyurethane resin used in the present invention is preferably 2,000 to 100,000, more preferably 5,000 to 70,000.

  The hydroxyl group content of the polyhydroxy polyurethane resin used in the present invention is preferably about 3 to 30% by mass (hydroxyl value 25 to 300 mgKOH / g). When the hydroxyl group content is less than the above range, the effect of reducing carbon dioxide is insufficient. On the other hand, when the hydroxyl group content exceeds the above range, various physical properties as a polymer are insufficient.

  In the polyhydroxypolyurethane resin used in the present invention, the hydroxyl group produced by the reaction of the 5-membered cyclic carbonate compound with the amine compound brings about further improvement in the performance of the printing ink binder of the present invention. Since the hydroxyl group has hydrophilicity, the adhesiveness to the plastic film can be remarkably improved, and furthermore, an antistatic effect that cannot be achieved by the conventional product can be obtained. Further, heat resistance can be further improved by utilizing a reaction between a hydroxyl group and a crosslinking agent.

  As the printing ink binder of the present invention, the polyhydroxy polyurethane resin can be used as it is, but the polyhydroxy polyurethane resin can also be used as a crosslinked film using a crosslinking agent. As the usable crosslinking agent, any crosslinking agent that reacts with a hydroxyl group can be used, and examples thereof include alkyl titanate compounds and polyisocyanate compounds. Known polyisocyanate compounds conventionally used for crosslinking polyurethane resins are preferred, but are not particularly limited.

  Furthermore, since the hydroxyl group in the polyhydroxy polyurethane resin used in the present invention is a secondary hydroxyl group, the reaction with the crosslinking agent depends on the temperature. The reaction hardly occurs at room temperature (10-30 ° C), and it has an unprecedented feature that it reacts at a heating temperature of 70 ° C or higher. Then, it can be used without problems in practice.

  Examples of the crosslinking agent include adducts of polyisocyanates having the following structural formula with other compounds, together with diisocyanate compounds used for the synthesis of polyurethane resins.

  In addition, in order to improve the blocking property and printability of printing ink, as well as the resistance to rubbing against printed matter and the storage stability of printing ink, other various known resin binders are used in combination with polyhydroxypolyurethane. be able to. As the other binder, those capable of chemically reacting with a crosslinking agent such as the above-mentioned polyisocyanate adduct are preferable, but those having no reactivity can also be used in the present invention.

  Specifically, a resin having compatibility with polyhydroxypolyurethane resin can be used in combination, such as acrylic resin, rosin-modified maleic acid resin, nitrified cotton, polyamide resin, chlorinated polypropylene, polyurethane resin, vinyl chloride-acetic acid. Examples include vinyl copolymer resins. Content of the said resin is 1-100 mass% with respect to the said polyhydroxy polyurethane resin. Furthermore, 3-30 mass% is suitable for the total content of the binder in printing ink.

  Examples of the colorant used in the printing ink containing the printing ink binder of the present invention include organic and inorganic pigments and dyes used in general inks, paints, and recording agents. Organic pigments include azo, phthalocyanine, anthraquinone, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolinone, quinophthalone, azomethine azo, diketopyrrolopyrrole, and isoindoline. Pigments. It is preferable to use copper phthalocyanine for the blue ink and C.I. Pigment yellow 83 for the transparent yellow ink.

  Examples of inorganic pigments include carbon black, titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, bengara, aluminum, kaolin clay, talc, and mica. Further, a luster pigment obtained by coating a metal or metal oxide on a glass flake or block flake as a base material can be used.

  The colorant is preferably contained in an amount sufficient to ensure the density and coloring power of the printing ink, that is, in a proportion of 1 to 60% by mass relative to the total mass of the printing ink. Moreover, a coloring agent can be used individually or in combination of 2 or more types.

  The printing ink using the printing ink binder of the present invention is composed of the above-mentioned colorant, solvent, and surfactant, pigment dispersant, wax, antifoaming agent, etc. A printing ink can be produced by appropriately blending additives and kneading using a normal ink production apparatus such as a ball mill, attritor, sand mill, or bead mill.

  Next, the present invention will be described in more detail with reference to reference examples, specific polymerization examples, examples and comparative examples, but the present invention is not limited to these examples. In the following examples, “part” and “%” are based on mass unless otherwise specified.

Reference Example 1 (Production of 5-membered cyclic carbonate compound)
In a reaction vessel equipped with a stirrer, a thermometer, a gas introduction tube and a reflux condenser, a divalent epoxy compound represented by the following formula A (Japan Epoxy Resin Co., Ltd., Epicoat 828; epoxy equivalent 187 g / mol [Figure] 1]) After 100 parts, 100 parts of N-methylpyrrolidone and 1.5 parts of sodium iodide were added and dissolved uniformly, carbon dioxide gas was added at 0.5 liter / min. The mixture was heated and stirred at 80 ° C. for 30 hours while bubbling at a speed of 5 ° C.

  After completion of the reaction, the obtained solution was gradually added to 300 parts of n-hexane with high-speed stirring at 300 rpm, and the resulting powdered product was filtered with a filter, further washed with methanol, and N-methylpyrrolidone and Sodium iodide was removed. The powder was dried in a drier to obtain 118 parts (yield 95%) of a white powder 5-membered cyclic carbonate compound (1-A).

In the infrared absorption spectrum (Horiba FT-720) of the obtained product, the peak derived from the epoxy group in the vicinity of 910 cm ⁻¹ almost disappears in the product, and the cyclic that does not exist in the raw material in the vicinity of 1,800 cm ^−1. Absorption of the carbonyl group of the carbonate group was confirmed ([FIG. 2]). Moreover, the number average molecular weight of the product was 414 (polystyrene conversion, Tosoh; GPC-8220) ([FIG. 3]). In the obtained 5-membered cyclic carbonate compound (1-A), 19% of carbon dioxide is immobilized.

Reference Example 2 (Production of 5-membered cyclic carbonate compound)
Reference Example 1 except that an epoxy compound represented by the following formula B (manufactured by Toto Kasei Co., Ltd., YDF-170; epoxy equivalent 172 g / mol) was used instead of the divalent epoxy compound A used in Reference Example 1. To obtain 121 parts (yield 96%) of white powdered 5-membered cyclic carbonate compound (1-B). The product was confirmed by infrared absorption spectrum, GPC and NMR.
In the obtained 5-membered cyclic carbonate compound (1-B), 20.3% of carbon dioxide is immobilized.

Reference Example 3 (Production of 5-membered cyclic carbonate compound)
Reference Example except that the epoxy compound represented by the following formula C (EX-212 manufactured by Nagase ChemteX Corporation; epoxy equivalent 151 g / mol) was used instead of the divalent epoxy compound A used in Reference Example 1. In the same manner as in Example 1, 111 parts (yield 86%) of a colorless and transparent liquid 5-membered cyclic carbonate compound (1-C) was obtained. The product was confirmed by infrared absorption spectrum, GPC and NMR.
In the obtained 5-membered cyclic carbonate group compound (1-C), 22.5% of carbon dioxide is immobilized.

Polymerization Examples 1 to 3 (Production of polyhydroxy polyurethane resin)
A reaction vessel equipped with a stirrer, a thermometer, a gas introduction tube and a reflux condenser was replaced with nitrogen, so that the 5-membered cyclic carbonate compound obtained in Reference Examples 1 to 3 and the solid content were 60%. Ethyl acetate was added and dissolved uniformly. Next, a predetermined equivalent of the amine compound shown in Table 1 was added, and the mixture was stirred for 10 hours at a temperature of 90 ° C. until the amine compound could not be confirmed. After completion of the reaction, a mixed solution of ethyl acetate / isopropyl alcohol (= 6/4) was diluted to a solid content of 35%. Properties of the obtained three types of polyhydroxypolyurethane resins are as shown in Table 1.

Comparative polymerization example 1 (polyurethane resin)
A reaction vessel equipped with a stirrer, thermometer, gas introduction tube and reflux condenser was replaced with nitrogen, and 150 parts of polybutylene adipate having an average molecular weight of about 2,000 and 15 parts of 1,4-butanediol were mixed with 200 parts of ethyl acetate. And dissolved in a mixed organic solvent consisting of 50 parts of toluene, and slowly added dropwise with 172 parts of ethyl acetate dissolved in 62 parts of water-added MDI while stirring well at 60 ° C. The reaction was performed for 6 hours.
This solution had a viscosity of 3.2 MPa · s (25 ° C.) at a solid content of 35%. The film obtained from this solution had a breaking strength of 45 MPa, a breaking elongation of 480%, and a thermal softening temperature of 110 ° C.

Comparative polymerization example 2 (polyurethane polyurea resin)
Using the same apparatus as in Comparative Polymerization Example 1, 606 parts of polyester polyol having an average molecular weight of 1,800 and isophorone obtained by reacting a mixture of ethylene glycol and neopentyl glycol (molar ratio = 1/1) with adipic acid 94.1 parts of diisocyanate were charged and reacted at 90 ° C. for 10 hours under a nitrogen stream to obtain a prepolymer having a free isocyanate value of 1.02% by mass, and 300 parts of ethyl acetate was added thereto to obtain a urethane prepolymer solution. Next, the urethane prepolymer solution is added to a mixture consisting of 18.1 parts of isophoronediamine, 530 parts of ethyl acetate and 503 parts of isopropyl alcohol, and the mixture is stirred at 45 ° C. for 6 hours to be reacted to obtain a polyurethane polyurea resin solution. Got. This solution has a solid content of 35% and a viscosity of 1.6 MPa · s (25 ° C.). A film obtained from this solution has a breaking strength of 21 MPa and a breaking elongation of 250%, and the thermal softening temperature is 125 ° C. Met.

Examples 1-6 and Comparative Examples 1-4
(Preparation of printing ink)
Each mixture of compositions of Polymerization Examples 1-3 and Comparative Polymerization Examples 1-2, 30 parts of titanium white (rutile type), 20 parts of ethyl acetate and 20 parts of isopropyl alcohol was kneaded with a paint shaker. The white printing inks of Examples 1 to 6 and Comparative Examples 1 to 4 were prepared. As a two-component reactive ink, a polyisocyanate compound was added to the obtained white printing ink to obtain a printing ink (Table 2).

  Using the resulting printing ink, a gravure-printed film, and a simple gravure printing machine equipped with a gravure plate with a plate depth of 35 μm, surface-corona-treated stretched nylon film (NY film) discharge-treated surface, surface corona-treated stretched polyethylene Gravure printing is performed on one side of the surface corona-treated surface of the terephthalate film (PET film) and surface corona-treated stretched polypropylene film (OPP film) so that the thickness after drying is 3 μm, and dried at 50 ° C. to obtain a printed film The following performance test was conducted and the results shown in Table 3 were obtained.

(Adhesiveness)
A cellophane tape peeling test was performed on the printing surface of a film piece obtained by gravure printing a white printing ink on an NY film, a PET film, and an OPP film, and visually judged from the appearance of the printed film.
A: The printed film is not peeled off at all.
○: Less than 20% of the printed film is peeled off.
Δ: 20% or more and less than 50% of the printed film is peeled off.
X: 50% or more of the printed film is peeled off.

A two-component polyurethane adhesive is applied to the printed surface of a gravure-printed white printing ink on a NY film and PET film to a thickness of 3 μm, and a 60 μm polyethylene film is laminated with a laminator to form a laminar laminate film. Obtained.
(Boil aptitude)
Appearance change was observed after the laminate film was heated with hot water at 90 ° C. for 30 minutes.
(Double-circle): There is no Lami float.
○: Lami floats like a pinhole.
Δ: Delamination occurs in a stripe shape.
X: Delamination occurs on the entire surface.

(Lamination strength)
The laminate film was heated with hot water at 90 ° C. for 30 minutes, then cut to a width of 15 mm, measured with a peel tester for 180 ° peel strength (g / 15 mm), and compared with the strength before heat treatment.

(Environmental compatibility)
The environmental compatibility was judged as xx based on whether carbon dioxide was immobilized.

  According to the above invention, by using a polyhydroxypolyurethane resin as a binder for printing ink, the printed matter is excellent in boil resistance, retort resistance, printing suitability, adhesion, etc., and also from the viewpoint of the global environment, carbon dioxide. The printing ink binder is provided as an environmentally-friendly product by contributing to the reduction of greenhouse gases.

Claims (4)

A number-average molecular weight obtained by reacting an epoxy compound with a 5-membered cyclic carbonate compound obtained by reacting an epoxy compound and carbon dioxide with an amine compound is 2,000 to 100,000, and a hydroxyl value is 25 to 300 mgKOH / The main component is a polyhydroxypolyurethane resin g .
The epoxy compound is at least one of the compounds represented by the following formulae:
The amine compound is methylenediamine, ethylenediamine, trimethylenediamine, 1,3-diaminopropane, hexamethylenediamine, octamethylenediamine, phenylenediamine, 3,3′-dichloro-4,4′-diaminodiphenylmethane, 4,4. '-Methylenebis (phenylamine), 4,4'-diaminodiphenyl ether, 4,4'-diaminodiphenylsulfone, metaxylylenediamine, paraxylylenediamine, 1,4-cyclohexanediamine, 4,4'-diaminocyclohexylmethane 1,4′-diaminomethylcyclohexane, isophoronediamine, monoethanoldiamine, ethylaminoethanolamine, hydroxyethylaminopropylamine, and bis (aminopropyl) piperazine At least one Der printing ink binders, wherein Rukoto that.

The printing ink binder according to claim 1, wherein the polyhydroxy polyurethane resin contains 1 to 25 mass% of carbon dioxide. The printing ink binder according to claim 1 or 2 , further comprising another resin. A printing ink binder according to any one of claims 1 to 3,
A crosslinking agent capable of reacting with a hydroxyl group of the polyhydroxypolyurethane resin contained in the printing ink binder, at least one of an alkyl titanate compound and a polyisocyanate compound;
A printing ink comprising:

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