JP2017039835A - Laminate ink composition for soft packaging - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminate ink composition for soft packaging which can be applied to a wide range of films, and is excellent in a polyethylene extrusion laminate strength and suitability on various high functional films.SOLUTION: A laminate ink composition for soft packaging contains a polyurethane resin (A) containing an urea bond, a block isocyanate compound (B), a colorant (C), and an organic solvent (D).SELECTED DRAWING: None

Description

  The present invention relates to a laminate ink composition for soft packaging. In particular, it is a gravure ink for polyethylene extrusion laminating that can exhibit very good adhesion performance to a printed laminate substrate, and is a flexible packaging laminate for various films coated with inorganic or organic barrier coating materials. The present invention relates to an ink composition.

Polyethylene extruded laminate films are widely used as food packaging materials. A polyethylene extruded laminate film is produced by melt-extruding polyethylene and laminating it onto a laminate base film such as a biaxially stretched polyester film, a biaxially stretched polyamide film, or a biaxially stretched polypropylene film. In particular, in the case of a biaxially stretched polypropylene base material, there is a tendency that the extrusion laminate strength tends to be insufficient. Therefore, a laminate ink having an excellent laminate strength is desired.
In recent years, among the films used for film packages, high-functional films imparted with various barrier properties tend to increase. These high-performance films have an inorganic or organic barrier coating applied on the surface, and when these high-performance films are used as gravure or flexographic printing, the adhesion between the film and the ink is inhibited. When stored in a wound state, the ink film moves to a non-printing surface (blocking phenomenon), often causing trouble. These high-performance films exist in a wide variety depending on the type of business and purpose, such as oxygen barriers that block air and water vapor barriers that block water vapor for food and electronic parts to prevent the contents from being altered. Also, there are many technically undisclosed ones, and the current situation is that it is difficult to cope with compared with general film printing.

For example, in Patent Document 1 (Japanese Patent Application Laid-Open No. 2005-298618), a specific polyurethane resin and a vinyl chloride vinyl acetate copolymer resin having a hydroxyl group are used in a specific ratio, thereby providing excellent adhesion to a wide variety of films. The laminate ink for soft packaging having blocking resistance, laminate strength and suitability for boil retort is exemplified, but the above-mentioned extrusion laminate strength is not sufficient.
Conventionally, such soft packaging laminate products have improved the high adhesion to the substrate and the laminate strength by adding a silane coupling agent to the printing ink with polyurethane resin as a binder. It is illustrated (for example, patent document 2: Unexamined-Japanese-Patent No. 2001-2971). However, while the types of high-performance films are diversified, the adhesiveness to the printing medium and the laminate strength are still not sufficient. It is desired that high adhesiveness and laminate strength can be maintained for a wider range of high-performance films.

JP 2005-298618 A JP 2001-2971 A

  In addition to being applicable to a wide variety of films, the present invention aims to provide a laminate ink composition for flexible packaging that is particularly excellent in polyethylene extrusion laminate strength and suitability on various high-functional films. To do.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have found that a polyurethane resin (A) containing a urea bond, a blocked isocyanate compound (B), a colorant (C ) And an organic solvent (D) were found to be effective in solving the problem.

That is, the present invention includes a laminate for flexible packaging, which contains a polyurethane resin (A) containing a urea bond, a blocked isocyanate compound (B), a colorant (C) and an organic solvent (D) as essential components. The present invention relates to an ink composition.
The present invention also relates to a laminate ink composition for soft packaging, wherein the polyurethane resin (A) has a weight average molecular weight in the range of 10,000 to 100,000.
The present invention also relates to a laminating ink composition for soft packaging comprising 1 to 30% by weight of a polyether polyol resin having a number average molecular weight of 100 to 3500 in the polyurethane resin (A).
The present invention also relates to a laminate ink composition for soft packaging, which further contains a vinyl chloride / vinyl acetate copolymer resin (E) having a hydroxyl group.
In the present invention, the vinyl chloride vinyl acetate copolymer resin (E) having a hydroxyl group has a hydroxyl value of 50 to 200 mgKOH / g, and the content ratio of the vinyl chloride component in the copolymer resin is 80 to 95. The present invention relates to a laminating ink composition for soft packaging which is in weight percent.
Furthermore, this invention relates to the laminate ink composition for soft packaging whose organic solvent (D) is an organic solvent which does not have an aromatic group.
In addition, the present invention relates to a printed matter obtained by printing the laminate ink composition for soft packaging.

  According to the present invention, it is possible to obtain a laminate ink composition for flexible packaging that has both excellent extrusion adhesion and strength while maintaining excellent adhesion and blocking resistance to a wide variety of films.

  The present invention will be described in detail. “Ink” used in the following description means “printing ink”. “Part” means “part by weight”.

  The present invention is a laminate ink composition for flexible packaging, comprising a polyurethane resin (A) containing a urea bond, a blocked isocyanate compound (B), a colorant (C) and an organic solvent (D). .

  Specifically, the laminate ink composition for soft packaging of the present invention uses a binder resin containing the polyurethane resin (A) and the blocked isocyanate compound (B) as an organic solvent such as ethyl acetate, methyl ethyl ketone, toluene, and IPA, and various additions. Premix into the agent. A color pigment is added while stirring the solution with a dispersion stirrer and further stirred to obtain an ink composition in which the color pigment is sufficiently dispersed.

The polyurethane resin (A) used in the laminate ink composition for soft packaging of the present invention is used as a main resin and preferably has a urea bond. The urea bond concentration in the resin solid content is preferably in the range of 0.1 to 2.0 mmol / g, more preferably 0.3 to 1.5 mmol / g, still more preferably 0.5 to 1.0 mmol / g. It is a range.
The urea bond concentration here can be calculated by the following formula (1).
Urea binding concentration = {(X ₁ / M ₁ + X ₂ / M ₂ +... + X _i / M _i ) × 2− (W ₁ × OH ₁ + W ₂ × OH ₂ +... + W _i × OH _i ) / 56100} × 1000 / S Formula (1)
In the formula (1), the symbols are as follows.
X _1: the weight _{M 1} of a diisocyanate compound 1: molecular weight diisocyanate compound 1 _{X 2:} diisocyanate compound 2 weight _{M 2:} Molecular weight of the diisocyanate compound 2 _{X i:} the weight of the diisocyanate compound i _{M i:} diisocyanate compounds i molecular weight _{W 1} of : Weight OH _{1 of} polyol ₁ : Hydroxyl value W _{2 of} polyol 1: Weight OH _{2 of} polyol 2: Hydroxyl value W _{i of} polyol 2: Weight OH _{i of} polyol i: Hydroxyl value of polyol i S: Solid content of urethane resin weight

Furthermore, it is preferable to contain 1 to 30 parts of a polyether polyol resin having a number average molecular weight of 100 to 3500 with respect to 100 parts of the polyurethane resin (A). Although details will be described later, examples of the polyether polyol resin include polyether polyols of polymers or copolymers such as ethylene oxide, propylene oxide, and tetrahydrofuran. Specifically, a known general-purpose material such as a polyethylene glycol resin, a polypropylene glycol resin, or a polytetramethylene glycol resin may be used. By containing the polyether polyol resin in the above range, the adhesion on the high-functional barrier film is greatly improved, and as a result, the blocking resistance and the laminate strength are excellent. In order to particularly improve the adhesiveness, blocking resistance and laminate strength on the high-performance barrier film, a polyethylene glycol resin is particularly preferable among the polyether polyol resins.
When the number average molecular weight of the polyether polyol resin, which is a component of the polyurethane resin (A) used in the laminate ink composition for soft packaging of the present invention, is less than 100, the polyurethane resin (A) film tends to be hard and polyester. Adhesiveness to the film is deteriorated. When the number average molecular weight is larger than 3500, the polyurethane resin (A) film tends to be brittle, so that the ink film has poor blocking resistance. When the polyether polyol resin is less than 1 part with respect to 100 parts of the polyurethane resin (A), the solubility of the urethane resin in ketones, esters, and alcohol solvents is deteriorated. In addition, the re-solubility of the ink film in the solvent is deteriorated, and the tone reproducibility of the printed matter is inferior. Moreover, when it exceeds 30 parts, there exists a tendency for blocking resistance to be inferior.

  As the combined polyol used as needed for the polyurethane resin (A) used in the laminate ink composition for soft packaging of the present invention, various known polyols generally used in the production of polyurethane resins can be used. You may use together 1 type (s) or 2 or more types. For example, polyether polyols (1) of polymers or copolymers such as methylene oxide, ethylene oxide, and tetrahydrofuran; ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3 -Propanediol, 2-ethyl-2butyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, hexane Diol, Octanediol, 1,4-Butynediol, 1,4-Butylenediol, Diethylene glycol, Triethylene glycol, Dipropylene glycol, Glycerin, Trimethylolpropane, Trimethylolethane, 1,2,6-hexanetriol, 1, 2,4-butanetri Saturated or unsaturated low molecular polyols (2) such as alcohol, sorbitol, and pentaerythritol; these low molecular polyols (2) and adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, Dehydration condensation or polyhydric carboxylic acids such as fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, speric acid, azelaic acid, sebacic acid, trimellitic acid, pyromellitic acid or their anhydrides Polyester polyols (3) obtained by polymerization; polyester polyols obtained by ring-opening polymerization of cyclic ester compounds, for example, lactones such as polycaprolactone, polyvalerolactone, and poly (β-methyl-γ-valerolactone) (4); the low molecular polyols (2) and the like, for example, dimethyl carbonate, Polycarbonate polyols obtained by reaction with phenyl carbonate, ethylene carbonate, phosgene, etc. (5); polybutadiene glycols (6); glycols obtained by adding ethylene oxide or propylene oxide to bisphenol A (7); 1 molecule Acrylic obtained by copolymerizing one or more hydroxyethyl, hydroxypropyl acrylate, acrylhydroxybutyl, etc., or their corresponding methacrylic acid derivatives, for example, with acrylic acid, methacrylic acid or its ester A polyol (8) etc. are mentioned.

  Among the polyester polyols (3), a polymer diol obtained from a diol (glycol) and a dibasic acid is a low molecular weight compound having up to 5 mol% of the diols having three or more hydroxyl groups. The polyols (2) can be substituted.

  Examples of the diisocyanate compound used in the polyurethane resin (A) in the laminate ink composition for soft packaging of the present invention include various known aromatic diisocyanates, aliphatic diisocyanates, and alicyclic diisocyanates that are generally used in the production of polyurethane resins. Etc. For example, 1,5-naphthylene diisocyanate, 4,4′-diphenylmethane diisocyanate, 4,4′-diphenyldimethylmethane diisocyanate, 4,4′-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3- Phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, cyclohexane-1 , 4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, Melyl diisocyanate, dicyclohexylmethane-4,4′-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, 4,4-diphenylmethane diisocyanate, tolylene diisocyanate Bis-chloromethyl-diphenylmethane-diisocyanate, 2,6-diisocyanate-benzyl chloride, dimerisocyanate obtained by converting a carboxyl group of dimer acid into an isocyanate group, and the like. These diisocyanate compounds can be used alone or in admixture of two or more.

Examples of the chain extender used for the polyurethane resin (A) in the laminate ink composition for soft packaging of the present invention include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, and dicyclohexylmethane-4,4. In addition to '-diamine, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine , 2-hydroxy pyrrole ethylene diamine, di-2-hydroxy pyrrole ethylene diamine, di-2-hydroxy propyl ethylene diamine, etc. Amines can also be used. These chain extenders can be used alone or in admixture of two or more.
Moreover, a monovalent active hydrogen compound can also be used as a terminal blocking agent for the purpose of stopping the reaction. Examples of such compounds include dialkylamines such as di-n-butylamine and alcohols such as ethanol and isopropyl alcohol. Furthermore, amino acids such as glycine and L-alanine can be used as a reaction terminator, particularly when it is desired to introduce a carboxyl group into the polyurethane resin. These end blockers can be used alone or in admixture of two or more.

  The polyurethane resin (A) used in the laminating ink composition for soft packaging of the present invention is obtained by, for example, reacting polypropylene glycol and a combination polyol with a diisocyanate compound in an excess ratio of an isocyanate group, and a prepolymer of a terminal isocyanate group. The obtained prepolymer is used in an appropriate solvent, that is, an ester solvent such as ethyl acetate, propyl acetate or butyl acetate, which is usually used as a solvent for non-toluene gravure ink; acetone, methyl ethyl ketone, methyl isobutyl ketone, etc. Ketone solvents such as methanol, ethanol, isopropyl alcohol, n-butanol, etc .; hydrocarbon solvents such as methylcyclohexane, ethylcyclohexane, etc .; And / or a one-step process in which a polypropylene glycol and a combination polyol, a diisocyanate compound, a chain extender and / or a terminal blocker are reacted at once in a suitable solvent. Manufactured. Among these methods, in order to obtain a uniform polyurethane resin (A), it is preferable to use a two-stage method. When the polyurethane resin (A) is produced by a two-stage method, the total (equivalent ratio) of amino groups of the chain extender and / or end-capping agent is 1 / 0.9 to 1.3. It is preferable to make it react. When the equivalent ratio of isocyanate group to amino group is less than 1 / 1.3, the chain extender and / or the end-capping agent remain unreacted, the polyurethane resin turns yellow, or the odor after printing May occur.

The weight average molecular weight of the polyurethane resin (A) thus obtained is preferably in the range of 10,000 to 100,000, more preferably in the range of 15,000 to 80,000. When the weight average molecular weight of the polyurethane resin (A) is less than 10,000, there is a tendency that the blocking resistance of the ink composition obtained, the strength of the printed film, the oil resistance, etc. tend to be low, and it exceeds 100,000. In some cases, the viscosity of the resulting ink composition tends to be high and the gloss of the printed film tends to be low.
The content of the polyurethane resin (A) used in the laminate ink composition for soft packaging of the present invention in the ink is 4% by weight with respect to the total weight of the ink from the viewpoint of sufficient adhesion of the ink to the printing medium. As mentioned above, 25 weight% or less is preferable from a viewpoint of moderate ink viscosity and the work efficiency at the time of ink manufacture and printing, and also the range of 6 to 15 weight% is preferable.

  The urethane resin (A) used in the present invention can be used without particular limitation as long as it has the above-described composition. Among these, the active hydrogen-containing functional group in the polyurethane resin (A), for example, a hydroxyl group, primary, or A material containing a secondary amino group or the like is preferable because crosslinking of the polyurethane resin and the blocked isocyanate proceeds smoothly and the resulting printing ink layer becomes strong. In addition, even if the active hydrogen-containing functional group is not included in the urethane resin (A), if the ink layer is heated at a high temperature, the same result as in the case where the urethane resin (A) containing active hydrogen is used. Is obtained.

Next, the blocked isocyanate compound (B) used in the present invention will be described.
The blocked isocyanate compound (B) is obtained by masking the terminal isocyanate group of isocyanurate type polyisocyanate, burette type polyisocyanate, or adduct type polyisocyanate with a blocking agent. By using a block type isocyanate, the polyethylene extrusion strength is dramatically improved. At present, in order to improve the polyethylene extrusion laminate strength, non-block type isocyanate is used in combination, so-called two-component ink is used. However, there is a problem that the residual ink after use is not reusable. On the other hand, in the case of block-type isocyanate compounds, the change over time is extremely small, so there is no need for blending into two liquids, and there is no problem of discarding the remaining ink, and handling is the same as with one-liquid type inks. It is possible to obtain a high polyethylene extrusion strength.

  Preferred organic diisocyanates that are raw materials for the blocked isocyanate compound (B) are 1,6-hexamethylene diisocyanate, isophorone diisocyanate, 4,4′-diphenylmethane diisocyanate, xylylene diisocyanate, tolylene diisocyanate, naphthylene diisocyanate, and these. Of the mixture.

As blocking agents, malonic acid diester, acetoacetate ester, acetylacetone, etc. as active methylene compounds, acetooxime, ketoxime (methyl ethyl ketoxime, butanone oxime), etc. as oxime compounds, phenol, cresol, etc. as lactose compounds, lactam compounds Ε caprolactam and the like, and imidazole compounds include 2-methylimidazole and the like. The blocking agent is not necessarily one type, and can be used even if mixed.
Blocked polyisocyanate compounds obtained by blocking isocyanate groups with this blocking agent are also commercially available from various companies. For example, Duranate 17B-60PX (solid content 60%), Duranate manufactured by Asahi Kasei Chemicals Corporation. TPA-B80E (solid content 80%), Duranate MF-B60X (solid content 60%), Duranate E402-B80T (solid content 80%); Vestagon B1530 (solid content 100%) manufactured by Degussa Japan, Vestagon B1065 ( Solid content 100%), Vesta nut B1358 (solid content 100%), Vesta nut B1370 (solid content 60%), and the like, which can be appropriately selected.

  The addition amount of the blocked isocyanate compound in the laminate ink composition is preferably in the range of 0.1 to 25% by weight, more preferably 1 to 20%, still more preferably 5 to 15% in the resin solid content in the ink. In this range, not only the polyethylene extrusion laminate strength but also the dry laminate strength using an adhesive is increased. When the added amount of the blocked isocyanate compound is less than 0.1%, the above-mentioned polyethylene extrusion laminate strength is not improved, and when it exceeds 25%, blocking problems after printing and winding may occur.

  Examples of the colorant (C) used in 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, dictopyrrolopyrrole, isoindoline, etc. Pigments. Indigo ink is copper phthalocyanine, and transparent yellow ink is C.I. I. Pigment No Yellow 83 is preferably used.

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

Next, the organic solvent (D) used in the present invention will be described. In the laminate ink composition for soft packaging of the present invention, for example, aromatic organic solvents, ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, esters such as ethyl acetate, n-propyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate Examples of the solvent include alcohol solvents such as n-propanol, innopropanol, n-butanol, and propylene glycol monomethyl ether, and these can be used alone or in a mixture of two or more. In recent years, from the viewpoint of working environment, it is desirable not to use aromatic solvents such as toluene and xylene and solvents of ketones.

  Furthermore, in the laminate ink composition for soft packaging of the present invention, the suitability of boil and retort is further improved by adding the vinyl chloride vinyl acetate copolymer resin (E) having a hydroxyl group.

  The vinyl chloride vinyl acetate copolymer resin having a hydroxyl group preferably has a hydroxyl value of 50 to 200 mg KOH / g and a content ratio of vinyl chloride component in the copolymer resin of 80 to 95% by weight.

  The vinyl chloride vinyl acetate copolymer resin having a hydroxyl group used in the present invention can be obtained by two kinds of methods. One is obtained by copolymerizing vinyl chloride monomer, vinyl acetate monomer and vinyl alcohol in appropriate proportions. The other is obtained by copolymerizing vinyl chloride and vinyl acetate and then partially saponifying vinyl acetate. In the vinyl chloride vinyl acetate copolymer resin having a hydroxyl group, the properties of the resin film and the resin dissolution behavior are determined by the monomer ratio of vinyl chloride, vinyl acetate and vinyl alcohol. That is, vinyl chloride imparts toughness and hardness of the resin coating, vinyl acetate imparts adhesion and flexibility, and vinyl alcohol imparts good solubility in polar solvents.

  When used as a laminating ink for flexible packaging, it is necessary to satisfy all of these properties: adhesiveness, anti-blocking, laminate strength, boil retort suitability, print suitability, so vinyl chloride vinyl acetate copolymer resin with hydroxyl groups is appropriate Monomer ratios exist. That is, 80 to 95 parts by weight of vinyl chloride is preferable with respect to 100 parts by weight of vinyl chloride vinyl acetate copolymer resin having a hydroxyl group. If it is less than 80 parts by weight, the resin film has poor toughness and the blocking resistance is lowered. If it exceeds 95 parts by weight, the resin coating becomes too hard and the adhesiveness is lowered. The hydroxyl value obtained from vinyl alcohol is preferably 50 to 200 mgKOH / g. If it is less than 50 mgKOH / g, the solubility in a polar solvent is poor and the printability is poor. When it exceeds 200 mgKOH / g, the water resistance is lowered and the suitability for boil and retort becomes poor.

  Examples of the resin used in combination with the laminate ink composition for soft packaging according to the present invention as needed include resins other than the polyurethane resin and vinyl chloride-vinyl acetate copolymer resin, for example, chlorinated polypropylene resin, ethylene-acetic acid Vinyl copolymer resin, vinyl acetate resin, polyamide resin, acrylic resin, polyester resin, alkyd resin, polyvinyl chloride resin, rosin resin, rosin modified maleic acid resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, petroleum Examples thereof include resins. The combined resins can be used alone or in admixture of two or more. The content of the combined resin is preferably 1 to 25% by weight, more preferably 2 to 15% by weight, based on the total weight of the ink.

  In the present invention, a combination resin, extender pigment, pigment dispersant, leveling agent, antifoaming agent, wax, plasticizer, infrared absorber, ultraviolet absorber, fragrance, flame retardant and the like can also be included as necessary. .

  In order to stably disperse the pigment in the organic solvent, it is possible to disperse the resin alone, but it is also possible to use a dispersant in order to disperse the pigment stably. As the dispersant, anionic, nonionic, cationic, amphoteric surfactants can be used. For example, a comb-structure polymer compound obtained by adding polyester to polyethyleneimine, or an alkylamine derivative of an α-olefin maleic acid polymer may be used. Specific examples include Solsperz series (ZENECA), Ajisper series (Ajinomoto), and homogenol series (Kao). Further, BYK series (Bic Chemie), EFKA series (EFKA), and the like can be used as appropriate. The dispersant is preferably contained in the ink in an amount of 0.05% by weight or more based on the total weight of the ink from the viewpoint of the storage stability of the ink and 5% by weight or less from the viewpoint of the suitability for lamination. .1 to 2% by weight.

  The laminate ink composition for soft packaging of the present invention can be produced by dissolving and / or dispersing a resin, a colorant and the like in an organic solvent. Specifically, it is possible to produce a pigment dispersion in which a pigment is dispersed in an organic solvent with a polyurethane resin, and to produce an ink by blending the obtained pigment dispersion with other compounds as necessary. it can.

The particle size distribution of the pigment in the pigment dispersion is adjusted by appropriately adjusting the size of the grinding media of the disperser, the filling rate of the grinding media, the dispersion treatment time, the discharge speed of the pigment dispersion, the viscosity of the pigment dispersion, and the like. be able to. As a disperser, generally used, for example, a roller mill, a ball mill, a pebble mill, an attritor, a sand mill and the like can be used.
In the case where bubbles or unexpectedly large particles are included in the ink, it is preferably removed by filtration or the like in order to reduce the quality of the printed matter. A conventionally well-known filter can be used.

The ink viscosity produced by the above method is in the range of 10 mPa · s or more from the viewpoint of preventing the pigment from settling and being appropriately dispersed, and 1000 mPa · s or less from the viewpoint of workability efficiency during ink production or printing. preferable. In addition, the said viscosity is a viscosity measured at 25 degreeC with the Tokimec B-type viscometer.
The viscosity of the ink can be adjusted by appropriately selecting the type and amount of raw materials used, for example, a polyurethane resin, a colorant, an organic solvent, and the like. The viscosity of the ink can also be adjusted by adjusting the particle size and particle size distribution of the pigment in the ink.

  As the hue of the ink composition of the present invention, there are five basic colors such as yellow, red, indigo, black, and white, depending on the type of colorant used, and red (orange) as the process gamut external color, There are three colors: grass (green) and purple. Further, transparent yellow, peony, vermilion, brown, gold, silver, pearl, almost transparent medium for adjusting color density (including extender pigments if necessary), etc. are prepared as base colors. The boil retort ink is appropriately selected in consideration of pigment migration and heat resistance. The base ink of each hue is diluted with a diluting solvent to a viscosity and density suitable for gravure printing, and supplied alone or mixed to each printing unit.

  A polyester resin film is particularly preferable as a usable plastic film, but it is also widely used for various highly functional films in which an inorganic or organic barrier coating material is coated on the surface of other polypropylene, nylon, polyethylene resin films and the like. I can do it.

The present invention will be described more specifically with reference to examples. Hereinafter, both “parts” and “%” are based on weight.
In addition, the measurement of the weight average molecular weight by GPC (gel permeation chromatography) in this invention and a number average molecular weight (all are polystyrene conversion) was performed on condition of the following using the HLC8220 system by Tosoh Corporation.
Separation column: 4 TSKgelGMH _HR- N manufactured by Tosoh Corporation are used. Column temperature: 40 ° C. Moving layer: Tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd. Flow rate: 1.0 ml / min. Sample concentration: 1.0% by weight. Sample injection volume: 100 microliters. Detector: differential refractometer.
The viscosity was measured at 25 ° C. with a Tokimec B-type viscometer.

(Synthesis Example 1)
In a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube, 90 parts of neopentyl glycol adipate diol (hydroxyl value: 21.2 mgKOH / g) and 10 parts of polyethylene glycol (hydroxyl value: 111 mgKOH / g) and 13.79 parts of isophorone diisocyanate were reacted at 90 ° C. for 10 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group content of 2.60% by weight. Was added to obtain a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 6.06 parts of isophorone diamine, 0.45 parts of di-n-butylamine, 121.2 parts of ethyl acetate and 98.3 parts of isopropyl alcohol. The polyurethane resin solution A-1 was obtained by stirring for a time. The obtained polyurethane resin solution A-1 has a resin solid content concentration of 30.6% by weight, a weight average molecular weight (Mw) of the resin solid content of 70,000, and a urea bond concentration of {(13.79 ÷ 222). * 2- (90 * 21.2 + 10 * 111) / 56100) * 1000 / 120.3 = 0.55 mmol / g.

(Synthesis Example 2)
In a four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube, 90 parts of neopentyl glycol adipate diol (hydroxyl value: 21.2 mgKOH / g) and 10 parts of polypropylene glycol (hydroxyl value: 111 mgKOH / g) and 13.79 parts of isophorone diisocyanate were reacted at 90 ° C. for 10 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group content of 2.60% by weight. Was added to obtain a uniform solution of urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 6.06 parts of isophorone diamine, 0.45 parts of di-n-butylamine, 121.2 parts of ethyl acetate and 98.3 parts of isopropyl alcohol. The polyurethane resin solution A-2 was obtained by stirring for a time. The obtained polyurethane resin solution A-2 had a resin solid content concentration of 30.2% by weight, a weight average molecular weight (Mw) of the resin solid content of 70,000, and the urea bond concentration was calculated in the same manner as in Synthesis Example 1. 0.55 mmol / g.

(Synthesis Example 3)
A four-necked flask equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube was charged with 100 parts of neopentyl glycol adipate diol (hydroxyl value: 30.1 mg KOH / g) and 13.78 parts of isophorone diisocyanate, and nitrogen was added. After making it react at 90 degreeC under airflow for 10 hours and manufacturing the urethane prepolymer with an isocyanate group content rate of 2.60 weight%, 61.3 parts of ethyl acetate was added to this, and it was set as the uniform solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 6.06 parts of isophoronediamine, 0.45 parts of di-n-butylamine, 121.1 parts of ethyl acetate and 98.2 parts of isopropyl alcohol, The polyurethane resin solution A-3 was obtained by stirring for a time. The obtained polyurethane resin solution A-3 had a resin solid content concentration of 30.0% by weight, a weight average molecular weight (Mw) of the resin solid content of 40,000, and the urea bond concentration was calculated in the same manner as in Synthesis Example 1. It was 0.58 mmol / g.

As the isocyanate compound (B), the following two commercially available products were used in this example.
1) Isocyanate compound (B-1): Duranate MF-K60B manufactured by Asahi Kasei Corporation (hexamethylene diisocyanate type, dissociation temperature 90 ° C., non-volatile content 60%, NCO = 6.5% by weight, viscosity: 220 mPa · s / 25 ℃)
2) Isocyanate compound (B-2): Duranate 17B-60P manufactured by Asahi Kasei (hexamethylene diisocyanate system, dissociation temperature 130 ° C., non-volatile content 60%, NCO = 9.5% by weight, viscosity: 500 mPa · s / 25 ° C. Solvent: Propylene glycol monomethyl ether acetate PMA)

(Preparation of vinyl chloride vinyl acetate copolymer resin solution)
Vinyl chloride vinyl acetate copolymer resin having hydroxyl group used in combination with polyurethane resin (resin monomer composition is vinyl chloride / vinyl acetate / vinyl alcohol = 92/3/5, hydroxyl value (mgKOH) = 64 in weight%) acetic acid A 15% solution was made with ethyl, and this was made into a vinyl chloride resin solution (E-1).

[Example 1]
30 parts of the obtained polyurethane resin solution A-1, 2 parts of blocked isocyanate (B-1) (Duranate MF-K60B, hexamethylene isocyanate, dissociation temperature 90 ° C., non-volatile content 60%, manufactured by Asahi Kasei Corporation) Kneaded a mixture of 30 parts of vinyl chloride vinyl acetate copolymer resin solution E-1 (15% solution) having a hydroxyl group, 10 parts of phthalocyanine blue pigment (DIC Corporation FASTGEN Blue LA5380), and 27 parts of ethyl acetate, A blue printing ink was made.
The viscosity of the obtained printing ink was adjusted to 16 seconds (25 ° C.) with Zahn cup # 3 (manufactured by Kouaisha) with ethyl acetate, and shown in Tables 1 and 2 using a gravure proofing machine equipped with a 35 μm gravure plate. Various barrier films (T, U, V, W) and biaxially stretched polypropylene films (hereinafter referred to as OPP films: X, Y, Z) were printed and dried at 40 to 50 ° C. to obtain printed matter.
About the obtained printed matter, the adhesiveness to various barrier films, blocking resistance, the adhesiveness to an OPP film, and extrusion laminate strength were measured and evaluated. The results are shown in Table 1. The evaluation was performed by the following test method.
1) Adhesiveness (common to various barrier films and OPP films)
After leaving the printed matter for 1 day, a cellophane tape (manufactured by Nichiban Co., Ltd., 12 mm width) was attached to the printed surface, and the appearance of the printed film when it was rapidly peeled off was visually judged. The determination criteria were as follows.
○: The printed film was not peeled off at all.
Δ: 50 to 80% of the printed film remained on the film.
X: 50% or less of the printed film remained in the film.
2) Blocking resistance (various barrier films only)
The film is overlapped so that the printed surface and the non-printed surface of the printed matter are in contact with each other, a load of 10 kgf / cm ² is applied, and the film is allowed to elapse for 12 hours in an environment of 40 ° C. The state of was visually evaluated in three stages.
○: No transfer observed when the amount of ink transferred to the non-printing surface is 0% Δ: Transfer is observed at a rate of less than 20% ×: Transfer is achieved at a rate of 20% or more 3) Extrusion laminate strength Measurement (OPP film only)
After applying 0.1 g / m ^{2 of a} polyethyleneimine-based anchor coating agent to an OPP printed material, molten polyethylene is laminated at a thickness of 40 μm by an extrusion laminating machine to obtain a laminated product, and then the laminated film is 15 mm wide. And a 90 degree peel test was conducted at a pulling speed of 50 mm / min.

[Examples 2-6, Comparative Examples 1 and 2]
Inks were prepared and evaluated in the same manner as in Example 1 for Examples 2 to 6, and Comparative Examples 1 and 2 with the composition shown in Table 1.

Barrier film to be evaluated T: Dainippon Printing Co., Ltd. Alumina-deposited transparent PET film IB-PET-PUB (thickness: 12 μm)
U: manufactured by Mitsubishi Plastics, Inc. Silica-deposited transparent PET film, Tech Barrier TX-R (thickness: 12 μm)
V: manufactured by Oike Industry Co., Ltd. Silica-deposited transparent PET film MOS-TEB (thickness: 12 μm)
W: manufactured by Toppan Printing Co., Ltd. Aluminum oxide-deposited transparent PET film GL-ARH (thickness: 12 μm)

OPP film X to be evaluated: P2161 (thickness: 20 μm) manufactured by Toyobo Co., Ltd.
Y: U-1 (thickness 20 μm) manufactured by Mitsui Chemicals Tosero Co., Ltd.
Z: Futamura Chemical Co., Ltd. FOR (thickness: 20 μm)

  The laminating ink composition for soft packaging of the present invention exhibits high adhesion and block resistance, even when it is a high-functional film subjected to various types of barrier treatments, and has high extrusion laminating strength on an OPP film. As a laminating ink composition for soft packaging, it can be widely used in applications for industrial products such as food packaging materials, sanitary products, cosmetics and electronic parts.

Claims (7)

  A laminate ink composition for flexible packaging, comprising a polyurethane resin (A) containing a urea bond, a blocked isocyanate compound (B), a colorant (C) and an organic solvent (D).   The laminate ink composition for soft packaging according to claim 1, wherein the polyurethane resin (A) has a weight average molecular weight in the range of 10,000 to 100,000.   The laminate ink composition for soft packaging according to claim 1 or 2, wherein the polyurethane resin (A) contains 1 to 30% by weight of a polyether polyol resin having a number average molecular weight of 100 to 3500.   Furthermore, the laminated ink composition for flexible packaging as described in any one of Claims 1-3 containing the vinyl chloride vinyl acetate copolymer resin (E) which has a hydroxyl group.   The hydroxyl value of the vinyl chloride vinyl acetate copolymer resin (E) having a hydroxyl group is 50 to 200 mgKOH / g, and the content ratio of the vinyl chloride component in the copolymer resin is 80 to 95% by weight. Item 5. The laminated ink composition for soft packaging according to any one of Items 1 to 4.   The laminate ink composition for soft packaging according to any one of claims 1 to 5, wherein the organic solvent (D) is an organic solvent having no aromatic group.   The printed matter formed by printing the laminate ink composition for soft packaging as described in any one of Claims 1-6.