JP2010053193A - High-luminance laminate ink composition, and retort-resistant soft packaging material formed by using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retort-resistant high-luminance laminate ink composition for use in the soft packaging materials which have the boil/retort resistance and which are excellent in the design property and euphemism property, and to provide a retort resistant soft packaging material formed by using the same. <P>SOLUTION: This retort-resistant, high-luminance laminate ink composition is such that a high-luminance ink composition including: a resin-covered aluminum paste which is obtained by covering an aluminum fine powder having a particle diameter of 5-20 μm with an acrylic resin; and a binder resin, has a solid content of the resin-covered aluminum paste of 2-30 wt.%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a retort-resistant high-brightness laminate ink composition having a resin-coated aluminum paste. More specifically, in a resin-coated aluminum paste having an acrylic resin coating layer on the surface of an aluminum fine powder, when the paste is blended with ink, it has excellent retort resistance and chemical resistance. The present invention relates to a laminate ink composition and a retort-resistant soft packaging material using the same.

    In recent years, high-intensity metallic coating and printing have been performed on various personal products such as plastic coating of cosmetics and home appliances such as televisions, audios, and mobile phones. In these cases, aluminum pigments with high brightness are often used. However, when the aluminum pigment used in these is printed on a film or the like and applied to a product for flexible packaging, the printed surface of the aluminum pigment often fades or disappears due to the boil / retort treatment. It was. Since aluminum has strong chemical activity, it has been necessary to firmly coat the surface of the aluminum fine powder by some method.

  Even if the aluminum surface was coated with a resin, it was difficult to completely block contact with highly active aluminum. For example, Japanese Patent Application Laid-Open No. 2001-115061 discloses that a printing ink containing a resin-coated aluminum pigment, a crosslinkable resin, and a curing agent are added to a coating solution to strengthen the ink layer and the coating layer itself. However, even if the ink film is sufficiently cured, it has been difficult to completely prevent discoloration and disappearance derived from the activity of aluminum.

In particular, in the flexible packaging field based on plastic films, high brightness laminate inks that have printability for various films and excellent retort resistance are desired, but have such retort resistance. There was no laminating ink.
JP 2001-115061 A JP 2002-121423 A Japanese Patent Laid-Open No. 9-71734 JP 2003-213157 A JP 2005-146111 A

  The object of the present invention is to solve the problems associated with retort treatment as described above, and to provide a high-intensity laminate ink composition for retort resistance using a resin-coated aluminum paste that is excellent in chemical resistance and brightness. It is to provide a retort-resistant soft packaging material to be used.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have a specific resin layer thickness in an aluminum paste coated with an acrylic resin, which has excellent retort suitability for flexible packaging materials. And found the present invention.

That is, the present invention relates to an ink composition. The first invention is a high-luminance ink composition comprising a resin-coated aluminum paste obtained by coating an aluminum fine powder having a particle size of 5 to 20 μm with an acrylic resin, and a binder resin. It is related with the high-intensity laminated ink composition for anti-retort characterized by being 2-30 weight% in conversion of solid content in a composition.
The second invention is a high-intensity laminating ink composition for anti-retort according to the first invention, wherein the thickness of the resin coating layer of the aluminum fine powder coated with acrylic resin is 0.02 to 0.05 μm Related to things.
The third invention is described in the first invention 1 or the second invention, wherein the unsaturated monomer constituting the acrylic resin contains 5% or more of a monomer having two or more unsaturated double bonds. The present invention relates to a high brightness laminate ink composition for anti-retort.

  A fourth invention relates to the high-intensity laminating ink composition for retort resistance as described in any one of 1 to 3, wherein the binder resin of the high-intensity laminating ink composition contains a polyurethane resin.

  A fifth invention relates to a high-luminance laminating ink composition for retort resistance according to the fourth invention, wherein the binder resin of the high-luminance laminating ink composition contains a vinyl acetate resin.

  A sixth invention relates to a retort-resistant soft packaging material for foods comprising the retort-resistant high-luminance laminate according to any one of the first to fifth inventions.

When the high-intensity laminate ink composition for retort resistance of the present invention is used for a soft packaging material, the ink printed part does not fade or disappear even when boil / retort treatment is performed.
The characteristic brightness can be maintained. Therefore, a soft packaging material excellent in design and aesthetic properties can be obtained.

      Unlike the conventional brightness ink, the high brightness laminate ink composition of the present invention can also be applied to foods that have a boil and retort treatment process.

  Hereinafter, the present invention will be described in more detail.

  The resin-coated aluminum paste used in the high-brightness laminated ink composition of the present invention imparts a sense of brightness, for example, a metal click to the ink film, and enhances the design and aesthetics of the entire product through vision. In general, the brightness of the film depends not only on the color tone unique to the aluminum fine powder, but also on the structure factor due to the arrangement and orientation of the aluminum fine powder in the ink film or in the vicinity of the ink surface. In order to obtain a feeling of brightness, it is necessary to optimize the properties of the aluminum fine powder, for example, the surface treatment method, the particle diameter, or the concentration.

  As aluminum fine powder, what was manufactured by the well-known method can be used. For example, there are a ball milling method, a stamp mill method, a vapor deposition crushing method, and the like. The aluminum fine powder can be treated with a fatty acid or the like to obtain an appropriate particle size, size, and stability.

  A conventional general aluminum paste is generally manufactured by subjecting a fine aluminum powder material to a flake shape (scale-like shape) with a ball mill or other pulverizer and then subjecting it to a surface treatment with a fatty acid. There are two types, fatty leaf type and non-leafing type, depending on the type of fatty acid. In these two types, the arrangement of aluminum in the ink coating layer varies depending on the surface treatment agent.

  In the present invention, the aluminum fine powder is coated with an acrylic resin and belongs to non-leafing type. The coating with an acrylic resin is obtained by polymerization, generally radical polymerization, from a polymerizable unsaturated monomer.

  Examples of the monomer having an unsaturated double bond include (meth) acrylic acid alkyl esters such as lauryl, methoxyethyl (meth) acrylate, methoxybutyl (meth) acrylate, and ethoxybutyl (meth) acrylate; (Meth) acrylic acid esters having a hydroxyl group such as 2-hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate; unsaturated monomers having an epoxy group such as glycidyl (meth) acrylate and allyl glycidyl ether; acrylamide N, N-methylol (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-methylacrylamide, N, N-dimethylacrylamide, N-isopropylacrylamide and other unsaturated monomers having an amide group; N, N- Dimethylaminoethyl meta (Meth) acrylic acid having a tertiary amino group such as relate, N, N-diethylaminoethyl methacrylate, N, N-dimethylaminopropyl methacrylate; nitrogen-containing compounds such as N-vinylpyrrolidone, N-vinylimidazole and N-vinylcarbazole Unsaturated monomer: Cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate, cycloaliphatic (meth) acrylate such as isobornyl (meth) acrylate, styrene, α-methylstyrene, benzyl acrylate, benzyl methacrylate, phenoxyethyl acrylate, etc. Aromatic unsaturated monomers; silicon-containing unsaturated monomers such as vinyltriethoxysilane and γ-methacryloyloxypropyltrimethoxysilane; octafluoropentyl (meth) acrylate, perfluorocyclohexyl Fluorine-containing unsaturated monomers such as (meth) acrylates, monomers having one unsaturated group such as unsaturated monomers blocked with isocyanate groups, divinylbenzene, polyethylene glycol di (meth) acrylate, etc. And a bifunctional unsaturated monomer. Examples of the unsaturated monomer having no active hydrogen include unsaturated monomers that do not contain a carboxyl group, a hydroxyl group, a methylol group, a silanol group, an amide group, a primary or secondary amino group, among the unsaturated monomers. A monomer is mentioned.

  In addition, examples of the monomer having three or more unsaturated double bonds include trimethylolpropane triacrylate, trimethylol triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, and the like.

  In the present invention, it is preferable to use 5% or more of a monomer having two or more unsaturated double bonds in the acrylic resin and 10% or more of a monomer having an aromatic ring. As the monomer having two or more unsaturated double bonds, trimethylolpropane triacrylate is preferable. Styrene is preferred as the monomer having an aromatic ring.

  The acrylic resin is preferably obtained by radical polymerization of an unsaturated monomer. As the polymerization initiator, both a water-soluble initiator and an oil-soluble initiator can be used. These polymerization initiators are suitably used within a range of 0.05 to 5% with respect to the unsaturated monomer. The temperature is preferably 40 to 100 ° C., and 80 ° C. or less is sufficient for the redox initiator. Examples of the polymerization initiator include azo compounds such as azobisisobutyronitrile and azobisisobutylvaleronitrile, benzoyl peroxide, isobutyryl peroxide, octanoyl peroxide, cumylperoxyoctate, t-butylperoxy- Organic peroxides such as 2-ethylhexanoate, t-butyl peroxyacetate, lauryl peroxide, di-t-butyl peroxide, di-2-ethylhexyl peroxydine carbonate, potassium persulfate, ammonium persulfate, hydrogen peroxide And other inorganic peroxide compounds. The organic or inorganic peroxide compound can also be used as a redox initiator in combination with a reducing agent. Examples of the reducing agent used include L-ascorbic acid, L-sorbic acid, sodium metabisulfite, ferric sulfate, ferric chloride, Rongalite and the like.

  The coating of the aluminum fine powder with the acrylic resin can be obtained, for example, by polymerizing an unsaturated monomer in the presence of the aluminum fine powder in a stainless steel reaction vessel using a solvent such as mineral spirit, hexane, or solvent naphtha. . In the polymerization, a crosslinking agent or curing agent having two or more unsaturated double bonds is used for the purpose of crosslinking, or a known chain transfer agent such as octyl mercaptan, lauryl mercaptan, 2-mercapto for the purpose of adjusting the molecular weight. Ethanol, tert-dodecyl mercaptan, thioglycolic acid or the like can also be used. The polymerization is preferably performed at a reaction temperature of 60 to 110 ° C. for 1 to 7 hours in a nitrogen atmosphere. Further, the polymerization initiator concentration is preferably 0.01 to 10% by weight or less. After the polymerization of the unsaturated monomer, the solvent is replaced with a target solvent, or the unreacted monomer, the resin that is not adsorbed or fixed to the surface, and the like are removed.

The aluminum fine powder used in the present invention preferably has a particle size of 5 to 20 μm. When the particle size is 5 μm or less, the viscosity of the obtained ink is increased, the leveling property is lowered, and the printing effect (appearance quality of the printed matter) is lowered. In the case of 20 μm or more, the hiding power of the ink coating film tends to decrease, the generation of doctor stripes, and the printing effect tends to decrease. More preferably, it is 8-15 micrometers.
The aluminum fine powder generally has a scaly shape, and the shape is represented by the particle diameter and thickness. The particle diameter is an average particle diameter on the side of a large particle surface and is measured by direct observation using a particle size distribution measuring device by light scattering or an electron microscope. In the present invention, the particle diameter determined by the light scattering method is the average particle diameter of D50 value (cumulative weight 50% particle diameter).

  The thickness of the resin coating layer of the resin-coated aluminum paste is such that the relative amount of the unsaturated monomer charged relative to the aluminum fine powder, the concentration of the polymerization initiator, and the monomer having two or more unsaturated double bonds. It can be adjusted according to the amount used. An acrylic resin is deposited on the surface of the aluminum fine powder by polymerization of an unsaturated monomer to form a resin layer. After completion of the reaction, it is made into a paste by filtration, washing, and solvent replacement steps. By preparing the aluminum paste by such a method, a printed matter, a laminate, and a flexible packaging bag that are extremely excellent in boil resistance, retort resistance, and brightness are obtained. The thickness of the acrylic resin coating layer is preferably 0.02 μm or more. If the thickness of the coating layer is 0.02 μm or less, the boil resistance and retort resistance tend to be inferior. The coating layer is preferably thicker, but if it is 0.05 μm or more, the resin layer is thick, so that the relative position and orientation of the aluminum paste in the ink film are affected, and the brightness is lowered. Therefore, it is preferably 0.02 to 0.05 μm.

  The thickness of the resin coating layer is directly obtained by a cross-sectional photograph taken with an electron microscope. For example, it is obtained by a method in which metal is vapor-deposited on resin-coated aluminum, embedded in an epoxy resin, cured, a cross section of aluminum is taken out by a microtome, and observed with an electron microscope.

  The solid content of the aluminum paste in the high brightness laminate ink composition is preferably 2 to 30% by weight. In the case of 2% by weight or less, the hiding power and the brightness feeling tend to decrease. In the case of 30% by weight or more, the viscosity of the ink increases and the ink fluidity decreases. More preferably, it is 5 to 20% by weight.

  Next, in the present invention, urethane resin, vinyl copolymer, vinyl acetate resin, polyamide resin, nitrified cotton, chlorinated polyolefin resin, alkyd resin, rosin resin and the like can be used as the binder resin. In the present invention, urethane resin or urethane resin / vinyl acetate resin is preferably used. Urethane resin has good adhesion to various base materials and is preferable for obtaining boil resistance and retort. Also, vinyl chloride resin is preferable in terms of stabilizing the aluminum paste in the ink and improving the blocking resistance after printing.

  The polyurethane resin usable in the present invention can be produced by a conventionally known method, and the production method is not particularly limited. For example, a polyol compound and an organic diisocyanate compound are reacted in an excess ratio of an isocyanate group to prepare a prepolymer having an isocyanate group at the end of the polyol, and then a chain extender and a reaction terminator in a solvent. A two-stage method of reacting is mentioned. The two-stage method is preferable because a uniform polymer solution can be easily obtained. As the solvent, an ester solvent, a ketone solvent, and an alcohol solvent may be used alone or in combination of two or more.

  Here, usable polyol compounds include polyether polyols such as polymers or copolymers such as ethylene oxide, propylene oxide, and tetrahydrofuran; ethylene glycol, 1,2-propanediol, 1,3-propanediol, Saturation of 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentadiol, methylpentadiol, hexadiol, octanediol, nonanediol, methylnonanediol, diethylene glycol, triethylene glycol, dipropylene glycol, etc. And unsaturated low molecular weight glycols, alkyl glycidyl ethers such as n-butyl glycidyl ether and 2-ethylhexyl glycidyl ether, and monocarbohydrate such as versatic acid glycidyl ester Acid glycidyl ester and dibasic acid such as adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, azelaic acid, sebacic acid, dimer acid Various known polyols such as polyester polyols obtained by dehydration condensation with acids or their anhydrides; other polycarbonate diols, polybutadiene glycols, glycols obtained by adding bisphenol A ethylene oxide or propylene oxide; dimer diols, etc. Can be mentioned. These polyols may be used alone or in combination of two or more.

  In addition, when using the polyol obtained from glycols and a dibasic acid among these polyols, up to 5 mol% of glycols can be substituted by various polyols. That is, for example, it may be substituted with a polyol such as glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, pentaerythritol.

  Although it determines suitably considering the solubility of the polyurethane resin obtained, drying property, blocking resistance, etc., the molecular weight of 500-6,000 is preferable normally. When the molecular weight is less than 500, the printability tends to be inferior with the decrease in solubility, and when it exceeds 6,000, the drying property and blocking resistance are deteriorated.

  Next, examples of the organic diisocyanate compound that can be used include various known diisocyanates of aromatic, aliphatic, and alicyclic groups. 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, cyclohexane-1,4- Diisocyanate, xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate Dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis (isocyanatemethyl) cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, dimerized isocyanate obtained by converting the carboxyl group of dimer acid to an isocyanate group, etc. It is.

  Next, the method for producing the polyurethane resin when the polyol compound and the organic diisocyanate are reacted is not particularly limited. For example, the conditions for reacting the polyol compound with the organic diisocyanate are not particularly limited except that the organic diisocyanate is excessive, but the molar equivalent ratio of isocyanate group / hydroxyl group is within the range of 1.2 / 1 to 3/1. It is desirable to be in Since the obtained polyurethane resin is brittle when the isocyanate group / hydroxyl molar equivalent ratio is 1.2 / 1 or less, blocking tends to occur when used in printing ink. On the other hand, if the molar equivalent ratio of isocyanate group / hydroxyl group is 3/1 or more, the viscosity becomes high in the production of the resin, and gelation is likely to occur during the reaction. Moreover, reaction temperature is normally performed between 80 degreeC-200 degreeC, Preferably it is good to carry out between 90 degreeC-150 degreeC.

  The polyurethane forming reaction may be performed in a solvent or may be performed in a solvent-free atmosphere. In the case of using a solvent, a solvent shown later may be appropriately selected and used from the viewpoints of temperature and viscosity during reaction and control of side reactions. When the polyurethane-forming reaction is carried out in a solvent-free atmosphere, it is desirable to raise the temperature and lower the viscosity to such an extent that stirring is sufficient in order to obtain a uniform polyurethane resin. The urethanization reaction is desirably carried out for 10 minutes to 5 hours, and the end point of the reaction is judged by viscosity measurement, NCO peak by IR measurement, NCO% measurement by titration, and the like.

  Furthermore, after reacting a polyol compound and an organic diisocyanate to synthesize a prepolymer having a terminal isocyanate group, a urea bond is introduced into the polyurethane resin using a chain extender and a reaction terminator to obtain a polyurethane / urea resin. Thus, the physical properties of the coating film are further improved.

  Next, various known amines can be used as a chain extender that can be used when a urea bond is introduced. For example, ethylenediamine, propylenediamine, hexamethylenediamine, triethylenetetramine, diethylenetriamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine and the like can be mentioned. In addition, 2-hydroxyethylethylenediamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypropylethylenediamine, di-2-hydroxypropylethylenediamine, etc. Representative examples thereof include diamines having a hydroxyl group and dimer diamine obtained by converting a carboxyl group of dimer acid into an amino group.

Then, as the reaction terminator available, aliphatic amine compounds having a C ₈ or more C ₂₂ or less long-chain alkyl groups, aliphatic amide compounds. As the aliphatic amine compound, octylamine, laurylamine, coconutamine, myristylamine, stearylamine, oleylamine, palmitylamine and the like can be used alone or in combination. Fatty acid amide compounds include octanoic acid amide, decanoic acid amide, lauric acid amide, myristic acid amide, palmitic acid amide, stearic acid amide, behenic acid amide, oleic acid amide, erucic acid amide, linoleic acid amide, linolenic acid amide, etc. These are used alone or in admixture of two or more.

An aliphatic amide compound having an aliphatic amine compound or C ₈ or C ₂₂ or less long chain alkyl group improves the blocking resistance by introducing the end of the polyurethane resin having a C ₈ or more C ₂₂ or less long-chain alkyl group To do. Since the long-chain alkyl group exhibits surface-active properties, it is considered that the long-chain alkyl group is oriented on the surface in the process of forming the coating film, thereby improving the blocking resistance of the polyurethane resin.

  The production method for introducing the urea bond into the polyurethane resin is not particularly limited, but the chain extender and the reaction terminator when the number of free isocyanate groups at both ends of the prepolymer is 1 are used. It is preferable that the total quantity of the amino groups in it is in the range of 0.5 to 1.3. When the total number of amino groups is less than 0.5, the drying property, blocking resistance and coating strength are not sufficient, and when it exceeds 1.3, the chain extender and the reaction terminator remain unreacted. , Odor is likely to remain on the printed matter.

  As the solvent used in the above production method, alcohol solvents such as methanol, ethanol, isopropanol, n-propanol, n-butanol, etc., well known as solvents for printing ink, acetone, methyl ethyl ketone, methyl isobutyl ketone Ketone solvents such as ethyl acetate, propyl acetate, and butyl acetate, and non-aromatic hydrocarbon solvents such as methylcyclohexane and ethylcyclohexane. These may be used alone or in a mixture of two or more. In addition, when said ketone solvent is used at the time of reaction, a ketimine arises between a ketone and the amine used as a chain extender, and smooth reaction is inhibited. It is desirable to use a small amount of water in order to suppress the generation of ketimine and facilitate the reaction.

  In the present invention, the urethane resin can be produced in an aromatic solvent, but it is preferable to use a non-aromatic solvent from the viewpoint of safety in the working environment. For example, ketone solvents, ester solvents, alcohol solvents and the like.

  The average molecular weight of the polyurethane resin is obtained by GPC (gel permeation chromatography) measurement, and indicates a weight average molecular weight calculated in terms of polystyrene. The average molecular weight is preferably in the range of 5,000 to 100,000. When the number average molecular weight of the polyurethane resin is less than 5,000, the drying property, blocking resistance, film strength, oil resistance, etc. of the printing ink using this as a binder are likely to be lowered, while exceeding 10,000. In this case, the viscosity of the printing ink tends to be high and the gloss of the printed film tends to be low.

  Next, in the present invention, a vinyl chloride resin can also be suitably used. The vinyl chloride resin is obtained by copolymerizing a vinyl chloride monomer, a fatty acid vinyl monomer, and a monomer having an unsaturated carbon-carbon double bond in one molecule and having a functional group.

  Examples of the fatty acid vinyl monomer used in the present invention include vinyl acetate, vinyl propionate, vinyl monochloroate, vinyl versakate, vinyl laurate, vinyl stearate, and vinyl benzoate.

  Here, examples of the functional group in the monomer having a carbon-carbon unsaturated double bond in one molecule and having a functional group include a hydroxyl group, a carboxyl group, an isocyano group, and an epoxy group.

  As monomers having a hydroxyl group, vinyl alcohol, 2-hydroxyethyl (meth) acrylate, 1-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, polyethylene glycol mono (Meth) acrylate, polypropylene glycol mono (meth) acrylate, hydroxystyrene, N-methylolacrylamide and the like.

  Examples of the monomer having a carboxyl group include (meth) acrylic acid, itaconic acid, isovaleric acid, maleic acid, fumaric acid, and derivatives such as (meth) acrylonitrile, (meth) acrylate, methyl (meth) acrylate, Examples thereof include alkyl (meth) acrylates such as butyl (meth) acrylate, ethylhexyl (meth) acrylate, stearyl (meth) acrylate, and benzyl (meth) acrylate.

  In addition, examples of the monomer having an isocyano group include (meth) acryloyloxyethyl isocyanate, (meth) acryloyloxypropyl isocyanate, and hydroxyalkyl such as 2-hydroxyethyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate. Examples thereof include those obtained by reacting (meth) acrylate with polyisocyanates such as toluene diisocyanate and isophorone diisocyanate.

  Examples of the monomer having an epoxy group include glycidyl methacrylate, glycidyl cinnamate, glycidyl allyl ether, glycidyl vinyl ether, vinylcyclohexane monoepoxide, 1,3-butadiene monoepoxide, and the like.

  Depending on the required performance, one of these or a mixture of two or more may be used.

  In this invention, it can manufacture by the conventionally well-known method as a polymerization method of vinyl chloride resin, and a manufacturing method in particular is not restrict | limited. For example, water, a dispersant, and a polymerization initiator are charged into a polymerization vessel, and after deaeration, a part of vinyl chloride monomer and a fatty acid vinyl monomer are injected to start the reaction, and the remaining vinyl chloride monomer is added during the reaction. A suspension polymerization method in which the polymerization is carried out while being injected is exemplified.

  Similar resins are commercially available, for example, Nissin vinyl manufactured by Nissin Chemical Co., Ltd.

  As the polymerization initiator, those used for the polymerization of the acrylic resin described above can be used as they are. For example, benzoyl peroxide, azoisobutyl valenonitrile, azobisisobutyronitrile, di-t-butyl peroxide, t-butyl perbenzoate, t-butyl peroctoate, cumene hydroxy peroxide, etc. are used, and the polymerization temperature is 50 It is -140 degreeC, Preferably it is 70-140 degreeC.

  The preferred weight average molecular weight of the resulting polymer is 5,000 to 100,000.

  As the solvent used in the above production method, an aromatic solvent can be used, but a non-aromatic solvent is preferable from the viewpoint of safety in work environment and hygiene. For example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone, ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether, and diethylene glycol dimethyl ether, ethyl acetate, and butyl acetate can be used. The solvent may be a mixture of two or more.

  The content ratio (solid weight ratio) of the polyurethane resin and the vinyl acetate resin used in the high-brightness ink composition of the present invention is preferably 95: 5 to 50:50 from the viewpoint of adhesion to the substrate. More preferably, it is 80: 20-60: 40.

  Next, as the solvent used in the high brightness laminate ink composition of the present invention, a non-aromatic solvent is preferable as described above. For example, alcohol organic solvents such as methanol, ethanol, n-propanol, isopropanol, butanol, ketone organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, ester organics such as methyl acetate, ethyl acetate, propyl acetate, butyl acetate Solvents, aliphatic hydrocarbon organic solvents such as n-hexane, n-heptane and n-octane, and alicyclic hydrocarbon organic solvents such as cyclohexane, methylcyclohexane, ethylcyclohexane, cycloheptane and cyclooctane In consideration of the solubility and drying property of the binder resin, it is preferable to use them by mixing. The amount of these organic solvents used is 30% by weight or more in ordinary ink.

  Furthermore, in the present invention, various hard resins and waxes can be added for the purpose of improving adhesiveness and various resistances.

  Here, examples of the hard resin include dimer acid resin, maleic acid resin, petroleum resin, terpene resin, ketone resin, dammar resin, copal resin, and chlorinated polypropylene. When these hard resins are used, an effect of improving adhesiveness can be expected particularly for a plastic film that has not been surface-treated.

  Moreover, in a high-intensity ink composition, a wax component can be contained for the purpose of improving blocking resistance. Various known waxes such as polyolefin wax and paraffin wax can be used as the wax.

  Furthermore, various ink additives such as leveling agents, surfactants, and plasticizers can be used as necessary.

  As a method for producing a high-brightness laminate ink composition using these materials, first, a binder resin, an organic solvent, and, if necessary, a surfactant and the like are sufficiently stirred and mixed with a disper, and then resin-coated aluminum. A method of adding and mixing the paste is preferable.

  The high-intensity laminate ink composition obtained from the above materials and production method is gravure-printed on the plastic film (1) as a gravure ink composition for back printing. Examples of the plastic film (1) include stretched and non-stretched polyolefins such as polyethylene and polypropylene, polyester, nylon, cellophane, and vinylon. For this application, polyethylene terephthalate and nylon which are polyester films are preferable.

  As the heat-sealable plastic film (2), low density polyethylene, medium density polyethylene, high density polyethylene, non-oriented polypropylene, oriented polypropylene and the like are preferable. The film thickness is preferably 25 to 80 μm.

  A barrier substrate can be provided between the plastic film (1) and the heat-sealable plastic film (2) as necessary. Examples of the barrier substrate include a metal vapor-deposited film, silica and / or alumina vapor-deposited film, and aluminum foil. By providing a barrier substrate, the influence of gas, light, etc. on the contents can be eliminated.

  As the printing configuration, the same configuration as that used for printing ordinary laminate ink is possible. For example, Configuration (A): Plastic Film (1) / High Brightness Laminating Ink Layer / Adhesive Layer / Heat Sealable Plastic Film (2), Configuration (B): Plastic Film (1) / High Brightness Laminating Ink Layer / Adhesion Agent layer / barrier substrate / adhesive layer / heat-sealable plastic film (2), composition (C): plastic film (1) / adhesive layer / barrier substrate / adhesive layer / high brightness laminate ink layer / Adhesive layer / Heat sealable plastic film (2) and the like.

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited to an Example. Unless otherwise specified, “parts” and “%” in this example represent “parts by weight” and “% by weight”.

(Preparation Example 1) <Preparation of resin-coated aluminum paste>
Aluminum pigment paste (without resin coating) 500 g, mineral spirit 5000 g, divinylbenzene 5 g, methyl methacrylate 50 g, butyl acrylate 25 g, styrene 20 g in a stainless steel reaction vessel equipped with a stirrer, thermometer, reflux condenser and nitrogen gas inlet tube Then, 0.3 g of azobisisobutyronitrile was charged, reacted at 80 ° C. for 3 hours, and cooled to obtain a reaction solution. Next, filtration and washing were performed, and the resin-coated aluminum paste (aluminum paste A) was obtained by replacing with propylene glycol monomethyl ether.

(Preparation Examples 2-7, 10, 11) <Preparation of resin-coated aluminum paste>
In Preparation Examples 2 to 7, 10, and 11, resin-coated aluminum paste was prepared in the same manner as Preparation Example 1. Table 1 shows the unsaturated monomers and initiators used. In addition, Preparation Examples 8 and 9 are aluminum pastes only with fatty acid treatment without resin coating.

(Adjustment Example 12) <Preparation of polyurethane resin>
(Polymerization example) 313 parts of polypropylene glycol having a number average molecular weight of 2,000, 63 parts of isophorone diisocyanate and 60.0 parts of ethyl acetate were added to a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser and a nitrogen gas introduction tube. The reaction was carried out at 90 ° C. for 6 hours under a nitrogen stream. Next, 21 parts of isophorone diamine, 360.0 parts of ethyl acetate and 180.0 parts of isopropyl alcohol were added, and a polyurethane resin varnish (urethane resin varnish) having a solid content of 40%, a viscosity of 200 mPaS at 25 ° C., and a weight average molecular weight of 9,000. Got. The molecular weight was calculated in terms of polystyrene using a GPC (Gel Permeation Chromatograph, Shodex DS-4, Showa Denko) equipped with a UV detector and a refractometer.

(Preparation Example 13) <Preparation of vinyl chloride-vinyl acetate copolymer varnish>
25 parts of vinyl chloride-vinyl acetate copolymer (vinyl chloride resin, Solvain TA5R manufactured by Nissin Chemical Co., Ltd.) was mixed and dissolved in 75 parts of ethyl acetate, and a vinyl chloride-vinyl acetate copolymer varnish for testing ( Salted vinegar bivarnish).

(Preparation Example 14) <Preparation of white ink>
Next, 12 parts of the urethane resin varnish obtained in Preparation Example 12, 19.2 parts of the vinyl chloride-vinyl acetate copolymer varnish (salt vinegar Vivar) obtained in Preparation Example 13, and titanium oxide (Titanics JR800 (Taika (Made by Co., Ltd.) 40 parts, mixed with 28.8 parts of methylcyclohexane: isopropyl alcohol: ethyl acetate = 40: 40: 20 (weight ratio), then dispersed and kneaded in a sand mill to give a white ink as a base. Created.

Example 1
Resin-coated aluminum paste A obtained in Preparation Example 1, 45 parts of urethane resin varnish obtained in Preparation Example 12, and 8 parts of vinegar vinegar obtained in Preparation Example 13, untreated silica (manufactured by Fuji Silysia Co., Ltd.) Cylicia 450 (particle size: 5.2 μm) was mixed with 1.0 part and 29.5 parts of a mixed solvent of methyl ethyl ketone: isopropyl alcohol: ethyl acetate = 40: 40: 20 (weight ratio), and then stirred with a disper for 20 minutes. A high brightness laminate ink composition A was obtained.

  Next, the high-intensity laminate ink composition A was printed on nylon (Ny, Emblem ON-RT, manufactured by Unitika Co., Ltd., film thickness 15 μm) with a gravure proofing machine (plate depth 30 μm), and subsequently obtained in Preparation Example 14. White ink was overprinted.

Laminates and heat seals were prepared for the purpose of evaluating and measuring retort resistance, laminate strength, heat seal strength and the like. The laminate is 3 g / m ^{2 in} solid content of an isocyanate-based adhesive (TM-250, CAT-RT80, both manufactured by Toyo Morton) on the printed matter.
An unstretched polypropylene film (Trefan ZK93K, manufactured by Toray Industries, Inc., 60 μm thick) was laminated and aged at 40 ° C. for 3 days to obtain an evaluation sample. As the heat seal product, the laminate was heat sealed at a heat seal temperature of 180 ° C., a nip pressure of 20 N / cm ² , and a heat seal time of 1 second to obtain an evaluation sample.

(Examples 2-7, Comparative Examples 1-6)
Table 2 shows the compounding ratios of aluminum paste, binder resin, and the like in Examples 2 to 7 and Comparative Examples 1 to 6. The preparation of the high brightness ink composition is the same as in Example 1. The same white ink as in Example 1 was used. Further, the printing, laminating, and creation of a heat-sealed product are the same as in the first embodiment.

  Printing effects, tape adhesion, alkali resistance, retort resistance, brightness, laminate strength, and heat seal strength were evaluated for the printed materials, laminates, and heat seal materials using the high-brightness laminate ink composition by the following methods. The results are shown in Table 3.

(Print effect)
The quality of ink leveling on the film printing surface was evaluated visually from the viewpoint of uniformity of color shading.
○: Leveling property is very good ○ △: 〃 Good △: 〃 Normal △ ×: 〃 Inferior ×: 〃 Very inferior (Evaluation of tape adhesion)
A cellophane tape (width: 12 mm, manufactured by Nichiban Co., Ltd.) was affixed to the film printing surface, pressure-bonded five times with fingers, and then the tape was peeled off. The adhesiveness to the film was evaluated by comparing the area where the tape was applied and the area where the ink film was peeled off from the film.
○: The ink film was not peeled at all ○ △: The area where the ink film was peeled was about 75% of the tape adhesion area Δ: 約 About 50% 〃
△ ×: 約 About 25% 〃
X: The surface of the ink film was peeled off (evaluation of alkali resistance)
A 3% NaOH solution was dropped onto the film printing surface and allowed to stand at room temperature for 24 hours, and then the discoloration was evaluated visually.
○: No fading ○ △: 〃 Very slight △: 多 い Many △ ×: 著 し い Remarkable ×: 〃 Extremely remarkable (Evaluation of brightness)
The brightness of the laminate was visually evaluated before and after retorting.
◯: Luminance is almost unchanged △: 〃 Slightly decreased △: 〃 Slightly decreased △ ×: 〃 Remarkable ×: 〃 Extremely remarkable (retort resistance test)
The laminate was made into a bag, filled with a mixture of vinegar: ketchup: salad oil = 1: 1: 1, heat sealed, and then retorted in hot water at 135 ° C. for 30 minutes in a retort kettle.
○: No fading ○ △: 〃 Very slight △: 多 い Many △ ×: 著 し い Significant ×: 〃 Extremely remarkable (laminate strength measurement)
The laminate was cut into strips with a width of 15 mm, and the laminate strength was measured with a peel tester (Tensilon, manufactured by Intesco) at a peel rate of 30 cm / min and a peel angle of 90 degrees (T-type peel).

(Measurement of heat seal strength)
The heat-sealed product was cut into a strip shape having a width of 15 mm and used as a sample. The measurement conditions are the same as the laminate strength measurement conditions.

DVB：ジビニルベンゼン
TMPTA：トリメチロールプロパントリアクリレート
MMA：メチルメタクリレート
BA：ブチルアクリレート
St：スチレン
AIBN：アゾビスイソブチロニトリル

DVB: Divinylbenzene
TMPTA: Trimethylolpropane triacrylate
MMA: Methyl methacrylate
BA: Butyl acrylate
St: Styrene
AIBN: Azobisisobutyronitrile

Claims (6)

  In a high-brightness ink composition comprising a resin-coated aluminum paste obtained by coating an aluminum fine powder having a particle size of 5 to 20 μm with an acrylic resin, and a binder resin, the resin-coated aluminum paste is solid in the high-brightness ink composition. A high-intensity laminating ink composition for retort resistance, which is 2 to 30% by weight in terms of minutes. 2. The high-intensity laminated ink composition for retort resistance according to claim 1, wherein the thickness of the resin coating layer of the aluminum fine powder coated with acrylic resin is 0.02 to 0.05 [mu] m. 3. The high-strength laminate ink composition for retort resistance according to claim 1 or 2, wherein the unsaturated monomer constituting the acrylic resin contains 5% or more of a monomer having two or more unsaturated double bonds. object.   The high-brightness laminating ink composition for retort resistance according to any one of claims 1 to 3, wherein the binder resin of the high-brightness laminating ink composition contains a polyurethane resin. The high-intensity laminating ink composition for retort resistance according to claim 4, wherein the binder resin of the high-intensity laminating ink composition contains a vinyl acetate resin. The retort-resistant soft packaging material for foodstuffs which consists of a retort-resistant high-intensity laminated body in any one of Claims 1-5.