WO2012173032A1 - Aqueous inkjet recording ink for lamination and method for producing laminate - Google Patents

Abstract

An aqueous inkjet recording ink for lamination, which contains (a) a pigment and (b) an aqueous resin, and which is characterized in that the aqueous resin (b) contains an aqueous polyurethane resin (b-1) that is produced through a process wherein a chain extender composed of a hydrazine derivative is reacted and an acrylic copolymer (b-2) that contains a carbonyl group or an amide group. A method for producing a laminate using the aqueous inkjet recording ink for lamination.

Description

Water-based inkjet recording ink for laminating and method for producing laminate

The present invention relates to an aqueous inkjet recording ink, and more particularly to an aqueous inkjet recording ink for laminating that can be used as laminating ink for packaging materials such as food.

Printing with an inkjet printer recording device is a method that ejects ink from nozzles and attaches it to the recording material. Unlike conventional printing, it is a printing method that does not use a plate, so it has become a small variety of products that have been in increasing demand in recent years. Demand is expanding as an on-demand printing method that can be supported.

One of the high-demand applications for such a small quantity and variety is packaging materials used for packaging foods and beverages. Usually, the packaging material uses a plastic film that is a non-absorbing substrate. The packaging material is printed directly on the surface of the plastic film, and printed on the back surface of the plastic film that is an outer layer with product protection and various functions. After that, there is a laminated packaging material in which an adhesive is applied on the printed layer and a sealant film that can be heat-sealed is bonded. The latter packaging material is excellent in aesthetics such as making use of the glossiness of the plastic film and preventing the scratch resistance of the ink, as well as strength to protect the contents from distribution, refrigeration, storage, heat sterilization, etc. Functions such as resistance to cracking, resistance to retort, and heat resistance can be imparted by combining a plurality of films, and this is the current mainstream.

Among these, laminating is usually performed by a roll-to-roll method. In this case, the film after printing is wound up once after drying and then unwound again in the adhesive coating process. At this time, since pressure is applied in a state where the printing surface and the back surface of the film are in contact with each other, a so-called blocking phenomenon may occur in which the printing surface sticks to the back surface.
In addition, the laminating ability is particularly important for laminated packaging materials. If the laminate strength is insufficient, there is a possibility that the package is peeled off after being filled with food or the bag is broken from the heat seal portion.

Conventionally, gravure ink has been used as printing ink for food packaging materials. In the case of gravure ink, for the blocking property, there is a formulation that prevents the blocking phenomenon by the effect of particles floating on the surface of the ink film by adding polyethylene wax or inorganic fine particles having a particle size of about several μm. Be taken. However, in the ink jet system, the nozzle diameter for ejecting ink is small and a sufficient effect cannot be obtained.
For laminating suitability, for example, an aqueous gravure printing ink for laminating using a polyurethane resin having a hydrazine residue in the molecule and not having a functional group that reacts with the hydrazine residue as a binder is known. (For example, refer to Patent Document 1). However, the gravure ink requires a printing plate, and there has been a problem that it takes too much cost and labor to cope with the recent small quantity and variety.
On the other hand, applying gravure ink to ink-jet ink has problems such as ink discharge properties and cannot be applied unconditionally.

JP-A-6-206972

The present invention provides a water-based inkjet recording ink for laminating that has good ejection properties, can form an image as an ink for packaging materials for foods, is less susceptible to blocking during the winding process, and has excellent laminating properties. There is to do.

As a result of intensive studies to solve the above problems, the present inventors have obtained an aqueous polyurethane resin (b-1) produced through a step of reacting a chain extender comprising a hydrazine derivative with a carbonyl group or By using an aqueous resin containing an amide group-containing acrylic copolymer (b-2), it is possible to form an image as an ink for packaging materials for foods with excellent ink ejection properties, and to give sufficient laminate strength. It has been found that a water-based inkjet recording ink for laminating can be obtained.

That is, the present invention is an aqueous inkjet recording ink for laminating processing comprising (a) a pigment and (b) an aqueous resin,
The aqueous resin (b) includes an aqueous polyurethane resin (b-1) produced through a step of reacting a chain extender comprising a hydrazine derivative, and a carbonyl group or amide group-containing acrylic copolymer (b-2). An aqueous inkjet recording ink for laminating, which is an aqueous resin containing

The present invention also includes a step of forming a printing layer on a non-absorbent substrate by an inkjet recording method using the water-based inkjet recording ink described above, and a step of forming an adhesive layer on the printing layer. And a method for producing a laminate comprising a step of laminating a sealant film layer on the adhesive layer surface.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to form an image as an ink for packaging materials for foods with good ejection properties, and a blocking phenomenon is hardly generated in the winding process, and it can be applied as a food packaging material having excellent laminating properties. A water-based inkjet recording ink for laminating that can give a laminate can be obtained.

Further, the laminate of the present invention is excellent in laminate suitability and is suitable as a food packaging material.

((A) Pigment)
The pigment used in the present invention is not particularly limited, and those usually used as pigments for water-based inkjet recording inks can be used. Specifically, it can be dispersed in water or a water-soluble organic solvent, and a known inorganic pigment or organic pigment can be used. Examples of the inorganic pigment include carbon black produced by a known method such as titanium oxide, iron oxide, a contact method, a furnace method, and a thermal method. Organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, dioxazines). Pigments, thioindigo pigments, isoindolinone pigments, quinofullerone pigments, etc.), dye chelates (for example, basic dye chelates, acidic dye chelates, etc.), nitro pigments, nitroso pigments, aniline black, and the like.

Specific examples of the pigment include carbon black, No. manufactured by Mitsubishi Chemical Corporation. 2300, no. 2200B, no. 900, no. 980, no. 33, no. 40, No, 45, No. 45L, no. 52, HCF88, MA7, MA8, MA100, etc. are Raven5750, Raven5250, Raven5000, Raven3500, Raven1255, Raven700, etc. manufactured by Columbia, Regal 400R, Regal 330R, Regal 660R, Mull 660R, Mull 660R Monarch 800, Monarch 880, Monarch 900, Monarch 1000, Monarch 1100, Monarch 1300, Monarch 1400, etc. are Degussa's Color Black FW1, FW2, FW2V, FW18, FW200, S170, U, S150, S35, P , V, 1400U, Special Black 6 , 5, 4, 4A, NIPEX150, NIPEX160, NIPEX170, NIPEX180, and the like.
Specific examples of pigments used in yellow ink include C.I. I. Pigment Yellow 1, 2, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 120, 128, 129, 138, 150, 151, 154, 155, 174, 180, 185 and the like.
Specific examples of pigments used in magenta ink include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 146, 168, 176, 184, 185, 202, 209, etc. It is done.
Specific examples of pigments used for cyan ink include C.I. I. Pigment blue 1, 2, 3, 15, 15: 3, 15: 4, 16, 22, 60, 63, 66, and the like.
In the present invention, a so-called self-dispersing pigment (surface-treated pigment) having a water dispersibility-imparting group on the pigment surface and capable of stably maintaining the dispersion state without a dispersant may be used. So-called capsule pigments (water-dispersible polymer-containing pigments) that can be stably maintained without a dispersant, or pigments dispersed with a dispersant may be used.

The pigment may be preferably dispersed in (b) an aqueous resin or a water-soluble solvent described later as a pigment dispersion dispersed by various pigment dispersants or surfactants.
The pigment dispersant is preferably an aqueous resin, and preferable examples include polyvinyl alcohols, polyvinylpyrrolidones, acrylic resins such as acrylic acid-acrylic acid ester copolymers, styrene-acrylic acid copolymers, styrene-methacrylic acid. Styrenes such as acid copolymers, styrene-methacrylic acid-acrylic acid ester copolymers, styrene-α-methylstyrene-acrylic acid copolymers, styrene-α-methylstyrene-acrylic acid-acrylic acid ester copolymers, etc. Examples thereof include acrylic resins, styrene-maleic acid copolymers, styrene-maleic anhydride copolymers, vinylnaphthalene-acrylic acid copolymers, and salts of the aqueous resins.
The compounds for forming the copolymer salt include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, and diethylamine, ammonia, ethylamine, triethylamine, propylamine, isopropylamine, Examples include propylamine, butylamine, isobutylamine, triethanolamine, diethanolamine, aminomethylpropanol, and morpholine. The amount of the compound used to form these salts is preferably equal to or greater than the neutralization equivalent of the copolymer.
Of course, it is also possible to use a commercial item. Commercially available products include Ajinomoto Fine Techno Co., Ltd. product Ajisper PB series, Big Chemie Japan Co., Ltd. Disperbyk series, BYK-series, and EFKA series manufactured by Ciba Specialty Chemicals.

((B) aqueous resin)
The aqueous resin (b) used in the present invention comprises an aqueous polyurethane resin (b-1) produced through a step of reacting a chain extender composed of a hydrazine derivative, and a carbonyl group or amide group-containing acrylic copolymer ( b-2) and an aqueous resin.
The aqueous resin (b) includes an —NHNH ₂ group at the molecular end of the aqueous polyurethane resin (b-1) generated by reacting a chain extender composed of a hydrazine derivative, and an acrylic copolymer (b-2). Reacts with the carbonyl group or amide group possessed by the resin, so that the resin has a crosslinking point at least after printing and drying. This is presumed to be the cause of the blocking phenomenon hardly occurring.

The aqueous polyurethane resin (b-1) and the acrylic copolymer (b-2) may be mixed in an aqueous medium. In this case, a resin having a crosslinking point after printing is dried. It becomes. Further, by copolymerizing various acrylic monomers as raw materials of the acrylic copolymer (b-2) in the presence of the aqueous polyurethane resin (b-1), the aqueous polyurethane resin (b- An aqueous dispersion of resin particles obtained by crosslinking 1) and the acrylic copolymer (b-2) can also be obtained. In the present invention, either system may be used, but an aqueous dispersion of resin particles obtained by the latter method is more preferable because of excellent storage stability because the reaction site has already reacted.

The aqueous polyurethane resin (b-1) produced through the step of reacting the chain extender comprising the hydrazine derivative is produced as follows. First, a urethane prepolymer is obtained by urethanizing diisocyanate with glycol and glycol having a carboxylic acid group.
Examples of the diisocyanates used at this time include aliphatic, alicyclic or aromatic diisocyanates. Examples of these are 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, and 4,4-diphenylmethane. diisocyanate, m- phenylene diisocyanate, xylylene diisocyanate, tetramethylene diisocyanate, lysine diisocyanate, 1,4-cyclohexylene diisocyanate, 4,4 '- dicyclohexylmethane diisocyanate, 3,3'-dimethyl-4,4-biphenylene diisocyanate, 3 , 3'-Dimethoxy-4,4-biphenylene diisocyanate, 3,3'-dichloro-4,4-biphenylene diisocyanate, 1,5-naphthalene diisocyanate, 1,5-tetrahydronaphtha Down diisocyanate, and isophorone diisocyanate.

As the glycols for preparing the urethane prepolymer, low molecular weight glycols, high molecular weight glycols, polyester diols, polycarbonate diols, etc. may be used alone or as well known in urethane technology. In addition, low molecular weight glycols may be used in combination with polyester diols and high molecular weight glycols.

Examples of the low molecular weight glycols include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-butylene glycol, tetramethylene glycol, mexamethylene glycol, decamethylene glycol, octanediol, tricyclodehydride. There are candimethylol, hydrogenated bisphenol A, cyclohexane dimethal, and the like, and two or more of these may be mixed.
Examples of the high molecular weight glycols include polyethylene glycol, polypropylene glycol, and polytetramethylene glycol.

As the polyester polyols, the glycols and dicarboxylic acids, for example, linear aliphatic dicarboxylic acids having 4 to 12 carbon atoms are preferable. Specific examples thereof include succinic acid, adipic acid, azelaic acid, sebacic acid. Aliphatic dicarboxylic acids such as decanedioic acid, dodecanedioic acid, terephthalic acid, isophthalic acid, 1,4-naphthalenedicarboxylic acid, 2,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, naphthalic acid, biphenyl What is necessary is just what reacted dicarboxylic acid, such as dicarboxylic acid, diphenic acid, and aromatic dicarboxylic acids, such as its anhydride, and it manufactures by a well-known method. Moreover, not only esterification reaction but transesterification reaction may be sufficient. Polyester polyols can also be produced by transesterification using lower alkyl esters of glycols and dicarboxylic acids.

The polycarbonate polyol may be any of those obtained by reacting the glycols with carbonates such as dimethyl carbonate, diethyl carbonate, ethylene carbonate, propylene carbonate and the like. It is manufactured by the method.

Examples of the glycols having a carboxylic acid group include 2,2-dimethylolpropionic acid, 2,2-dimethylolbutyric acid, 2,2-dimethylolvaleric acid, and the like.

The urethanization reaction is desirably performed in an organic solvent that is inert to isocyanate groups and has a high affinity for water, such as dioxane, acetone, methyl ethyl ketone, N-methylpyrrolidone, and tetrahydrofuran.

Next, the prepolymer is neutralized and chain-extended, and distilled water is added to obtain an aqueous polyurethane resin.
Examples of the neutralizing agent used for neutralization include amines such as trimethylamine, triethylamine, tri-n-propylamine, tributylamine, triethanolamine; sodium hydroxide, potassium hydroxide, ammonia and the like.

Specific examples of hydrazine or derivatives thereof used for chain extension include hydrazine, ethylene-1,2-dihydrazine, propylene-1,3-dihydrazine, butylene-1,4-hydrazine, and hydrates thereof. Etc.
Polyols such as ethylene glycol and propylene glycol, which are widely used as chain extenders for urethane prepolymers; ethylenediamine, propylenediamine, hexamethylenediamine, tolylenediamine, xylylenediamine, diphenyldiamine, diaminodiphenylmethane, diaminocyclohexylmethane, piperazine, Aliphatic, alicyclic and aromatic diamines such as 2-methylpiperazine and isophorone diamine tend to be inferior in laminate suitability, which is an effect of the present invention.

The acid value of the polyurethane resin is preferably 10 to 200 mgKOH / g per resin solid content. When the acid value is less than 10 mgKOH / g, when the urethane prepolymer reacted in an organic solvent is made aqueous by using a neutralizer, a chain extender, or distilled water, aggregates are likely to be formed, or the obtained aqueous polyurethane There is a possibility that the storage stability of the resin is poor. On the other hand, when the acid value exceeds 200 mgKOH / g, physical properties such as preferable durability and water resistance may not be obtained.

The glass transition temperature (hereinafter abbreviated as Tg) of the polyurethane resin is preferably set as appropriate depending on the desired application. For example, when printing the water-based inkjet recording ink of the present invention on a plastic film having flexibility such as for food packaging materials, the adhesion of the film when laminating and the flexibility of the packaging Because of the demand for flexibility, it is preferable that the glass transition temperature (hereinafter abbreviated as Tg) of the polyurethane resin is not so high. In order to achieve both good adhesion to a suitable film and flexibility, the Tg of the polyurethane resin used is preferably in the range of −80 ° C. to 30 ° C., more preferably in the range of −50 ° C. to 20 ° C.

The acrylic monomer that is a raw material of the carbonyl group or amide group-containing acrylic copolymer (b-2) has a carbonyl group-containing monomer or an amide group-containing monomer as an essential component. The blending amount is preferably at least 0.5 parts by weight with respect to 100 parts by weight of the total polymerizable monomer. In addition, conventionally known surfactants, protective colloids, and polymerization initiators used for emulsion polymerization can be used.

The carbonyl group-containing monomer is a monomer containing an aldo group or a keto group, and does not include a compound having only an ester bond or a carboxyl group.
Examples of the carbonyl group-containing monomer used in the present invention include acrolein, diacetone acrylamide, vinyl methyl ketone, vinyl ethyl ketone, vinyl butyl ketone, diacetone acrylate, acetonitrile acrylate and the like.
Examples of amide group-containing monomers include monoolefinic unsaturated carboxylic acid amides, N-alkyl derivatives of monoolefinic unsaturated carboxylic acid amides, and N-alkylol derivatives of monoolefinic unsaturated carboxylic acid amides. Can be mentioned. Examples of such monomers are amides of acrylic acid, methacrylic acid, itaconic acid or maleic acid; N-methylacrylamide, N-isobutylacrylamide, N-methylmethacrylamide, N-methylolacrylamide, N-methylolmethacrylic Examples thereof include amide, N-ethoxymethylacrylamide, Nn-butoxymethylacrylamide, N-isopropoxymethacrylamide and the like.

These carbonyl group-containing monomers or amide group-containing monomers may be used alone or in combination, but at least 0.5 parts by weight with respect to 100 parts by weight of the total polymerizable monomers. It is preferable to use it, and a particularly preferable region is 1.0 to 10.0 parts by weight.

In addition, acrylic monomers other than the above used for emulsion polymerization in the present invention include acrylic acid esters such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate; methyl methacrylate, methacrylic acid Methacrylic acid esters such as ethyl acid, and other polymerizable unsaturated monomers that can be copolymerized with the acrylic monomers, such as maleic acid, fumaric acid, itaconic acid esters; vinyl acetate , Vinyl esters such as vinyl propionate and vinyl tertiary carboxylate; aromatic vinyl esters such as styrene and vinyl toluene; heterocyclic vinyl compounds such as vinyl pyrrolidone; vinyl chloride, acrylonitrile, vinyl ether, vinyl ketone, vinyl amide Etc .; Halogens such as vinylidene chloride and vinylidene fluoride Fluoride compounds, ethylene, alpha-olefins such as propylene, dienes such as butadiene and the like.

Examples of the polymerizable unsaturated monomer having a reactive polar group include glycidyl compounds such as glycidyl acrylate, glycidyl methacrylate, and allyl glycidyl ether: vinyltrichlorosilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, Silane compounds such as γ-methacryloxypropyltrimethoxysilane; Acrylic acid, methacrylic acid, maleic acid or half-ester thereof, fumaric acid or half-ester thereof, itaconic acid or half-ester thereof, carboxyl compounds such as crotonic acid; β -Hydroxyl compounds such as hydroxyethyl acrylate and β-hydroxyethyl methacrylate; and amine compounds such as alkylamino acrylate and alkylamino methacrylate.

In the present invention, when using a system in which the aqueous polyurethane resin (b-1) and the acrylic copolymer (b-2) are mixed in an aqueous medium, the acrylic copolymer (b- After obtaining 2), each may be blended in a desired ratio.
Examples of a method for obtaining the acrylic copolymer (b-2) include known emulsion polymerization methods. Specifically, a radical polymerization initiator, the monomer, etc. are sequentially added to a mixture of water and an emulsifier (surfactant) while stirring with heating as necessary, and then polymerized. Can be obtained.
In the present invention, conventionally known surfactants (emulsifiers) used for emulsion polymerization can be used. Anionic emulsifiers such as sodium dodecylbenzene sulfate, sodium dodecylbenzene sulfonate, alkylaryl polyether sulfate, etc .; polyoxyethylene lauryl ether, polyoxyethylene nonylphenyl ether, polyoxyethylene-polyoxypropylene block copolymer Nonionic emulsifiers such as coalescents; and cationic emulsifiers such as cetyltrimethylammonium bromide and laurylpyridinium chloride can be appropriately selected and used. Moreover, it is also possible to use a water-soluble oligomer as a dispersant in place of the above-mentioned emulsifier or in combination with an emulsifier. Furthermore, it is also effective to use a water-soluble polymer substance such as polyvinyl alcohol or hydroxyethyl cellulose in combination with the above-mentioned emulsifier, or add it to the emulsion after polymerization.

The total amount of the emulsifier, the water-soluble oligomer and the water-soluble polymer substance is preferably used in the range of 0.5 to 10 parts by weight with respect to 100 parts by weight of the acrylic monomer. If it exceeds this, the water resistance of the printed matter may be inferior, and if the amount used is less than this, the stability during emulsion polymerization and the stability of the resulting emulsion polymer may be reduced.

As the radical polymerization initiator used in the emulsion polymerization of the acrylic copolymer (b-2), those used in usual emulsion polymerization can be used, and examples thereof include potassium persulfate, Examples thereof include ammonium persulfate, azobisisobutyronitrile, and hydrochloride thereof, and organic peroxides such as cumene hydroperoxide and tert-butyl hydroperoxide can also be used as necessary. Furthermore, known redox initiators using these persulfates or peroxides in combination with metal ions such as iron ions, and reducing agents such as sodium sulfooxylate formaldehyde, sodium pyrosulfite, and L-ascorbic acid. Can also be used.

The concentration during emulsion polymerization should be such that the final composition has a solid content of 25 to 65% by weight from a practical viewpoint, and the ethylenically unsaturated monomer and radical polymerization in the reaction system. The initiator can be carried out by any known method such as batch charging, continuous dropping, or divided addition.

The temperature at the time of emulsion polymerization may be within the range that is used in known emulsion polymerization, and the emulsion polymerization is performed under normal pressure or under pressure when a gaseous ethylenically unsaturated monomer is used.

In the blending ratio of the aqueous polyurethane resin (b-1) and the acrylic copolymer (b-2), the aqueous polyurethane resin (b-1) is increased by increasing the ratio of the aqueous polyurethane resin (b-1). ) Characteristics are emphasized and the laminate strength tends to be improved. On the other hand, by increasing the ratio of the acrylic copolymer (b-2), the characteristics of the acrylic copolymer (b-2) are emphasized. And blocking properties tend to be improved. From this, it is preferable to determine the blending ratio as appropriate according to the desired physical properties. Specifically, the water-based polyurethane resin (b-1) / the acrylic copolymer (b-2) is preferably blended so as to be 95/5 to 5/95. More preferably, 80/20 to 40/60 is particularly preferable.

On the other hand, by copolymerizing various acrylic monomers as raw materials of the acrylic copolymer (b-2) in the presence of the aqueous polyurethane resin (b-1), the aqueous polyurethane resin (b- An aqueous dispersion of resin particles obtained by crosslinking 1) and the acrylic copolymer (b-2) can also be obtained. In this case, a radical polymerization initiator, the monomer and the like are sequentially added to the mixture of the water, the emulsifier (surfactant) and the aqueous polyurethane resin (b-1) by a method such as dropwise addition, and polymerized. Can be obtained at

The water-based resin (b) used in the present invention emphasizes the resin properties of the water-based polyurethane resin (b-1) and the acrylic copolymer (b-2), and is effective in laminate strength and blocking properties. However, if the content in the ink is small, sufficient laminate strength cannot be obtained. On the other hand, if the content is too large, the viscosity increase and ejection are adversely affected. Accordingly, the resin solid content in the total amount of the ink is preferably 1.0 to 10.0% by weight, and particularly preferably 3.0 to 5.0%.

When the aqueous resin (b) used in the present invention is an aqueous dispersion, if its average particle size is too large, it will cause clogging of the head and cause ejection failure. For this reason, it is preferable that the average particle diameter of the polyurethane resin particles is as small as possible because the influence on ejection failure is small. Specifically, it is preferably in the range of 10 nm to 500 nm, and particularly preferably in the range of 10 to 100 nm.
Here, the particle diameter can be measured by a known and common centrifugal sedimentation method, laser diffraction method (light scattering method), ESA method, capillary method, electron microscope method, or the like. Preferable is measurement by Microtrac UPA using a dynamic light scattering method.

(Water-based inkjet recording ink for laminating)
The (a) pigment and the (b) aqueous resin are blended to obtain the water-based inkjet recording ink for laminating of the present invention.
The resin solid content (%) of the (b) aqueous resin is preferably 1.0 to 10.0% by weight based on the total amount of ink. By setting it within this range, an ink having an excellent balance between laminate suitability and blocking resistance can be obtained.

The blending method of the ink is not particularly limited, and can be performed by a generally used method. First, (a) a pigment (if necessary, (a) a pigment dispersion in which a pigment is dispersed with a pigment dispersant may be used), (b) an aqueous resin (various solvents after being adjusted by the above method) May be included), an aqueous solvent such as water or a water-soluble organic solvent, and, if necessary, a surfactant, a pigment dispersant, a viscosity modifier, an antifoaming agent, an antiseptic, etc. Examples of the dispersing and mixing method include a bead mill, a ball mill, a sand mill, an attritor, a roll mill, an agitator, a Henschel mixer, a colloid mill, an ultrasonic homogenizer, an ultrahigh pressure homogenizer, and a pearl mill. If necessary, various additives may be further added thereafter.

The water-soluble organic solvent used in the present invention is not particularly limited, but those that are miscible with water and can prevent clogging of the head of an inkjet printer are preferred. For example, glycerin, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol having a molecular weight of 2000 or less, propylene glycol, dipropylene glycol, tripropylene glycol, 1,3-propylene glycol, isopropylene glycol, isobutylene glycol, 1,4-butane Examples include diol, 1,3-butanediol, 1,5-pentanediol, 1,6-hexanediol, mesoerythritol, pentaerythritol, and the like. Among them, the inclusion of propylene glycol and 1,3-butyl glycol has safety and excellent effects in ink drying properties and ejection performance.

Further, examples of the surfactant used in the present invention include acetylene surfactants. For example, 2,4,7,9-tetramethyl-5-decyne-4,7-diol, 3,6-dimethyl-4-octyne-3,6-diol, 3,5-dimethyl-1-hexyne-3- In addition to all, commercially available products such as Surfinol 104, 82, 440, 465, 485, or TG (available from Air Products and Chemicals. Inc.), Olfin STG, Olfin E1010 (trade names manufactured by Nisshin Chemical Co., Ltd.) ) And the like.

(Laminate)
The water-based inkjet recording ink for laminating according to the present invention is used as a printing ink for laminates such as laminate films used for food packaging materials and the like.

The plastic film which is a non-absorbing substrate used in the present invention is not particularly limited as long as it is used for food packaging materials, and a known plastic film can be used. Specific examples include polyester films such as polyethylene terephthalate and polyethylene naphthalate, polyolefin films such as polyethylene and polypropylene, polyamide films such as nylon, polystyrene films, polyvinyl alcohol films, polyvinyl chloride films, polycarbonate films, polyacrylonitrile films, Examples include biodegradable films such as polylactic acid films. In particular, a polyester film, a polyolefin film, and a polyamide film are preferable, and polyethylene terephthalate, polypropylene, and nylon are more preferable. Moreover, the above-mentioned film coated with polyvinylidene chloride or the like for imparting a barrier property may be used, and if necessary, a film in which a deposited layer of a metal oxide such as aluminum or a metal oxide such as silica or alumina is used in combination. May be.

The plastic film may be an unstretched film, but is preferably stretched uniaxially or biaxially. Further, the surface of the film may be untreated, but those subjected to various treatments for improving adhesive properties such as corona discharge treatment, ozone treatment, low temperature plasma treatment, flame treatment, glow discharge treatment and the like are preferable.
The film thickness of the plastic film is appropriately changed according to the application. For example, in the case of a flexible packaging application, the film thickness is 10 μm to 100 μm assuming that it has flexibility, durability, and curl resistance. Preferably there is. More preferably, it is 10 μm to 30 μm.

A printing layer is formed on the plastic film with the water-based inkjet recording ink for laminating according to the present invention.
Any conventionally known method can be used as the ink jet recording method. For example, a method of ejecting droplets using vibration of a piezoelectric element (a recording method using an ink jet head that forms ink droplets by mechanical deformation of an electrostrictive element) or a method of using thermal energy can be given.

Next, an adhesive layer for laminating is formed on the printed layer. The adhesive used for the adhesive layer is not particularly limited as long as it is generally used for laminating, and a known adhesive can be used. Specific examples include acrylic resin, urethane resin, urethane-modified polyester resin, polyester resin, epoxy resin, ethylene-vinyl acetate copolymer resin (EVA), vinyl chloride resin, vinyl chloride-vinyl acetate copolymer resin, natural rubber, SBR. Adhesives such as synthetic rubber such as NBR, silicone rubber, etc., but preferably as one- or two-component curable polyether polyurethane adhesive, polyester polyurethane adhesive, polyester adhesive as an adhesive for dry lamination Good adhesive. As the adhesive for extrusion lamination, polyethyleneimine, alkyl titanate, polyurethane resin, urethane adhesive, and the like are preferable.

Next, a sealant film layer is formed by laminating.
As a laminating method, known lamination such as dry lamination, non-solvent lamination, extrusion lamination, etc. can be used.
Specifically, in the dry lamination method, the adhesive is applied to one of the base films by the gravure roll method, and the other base film is stacked and bonded by dry lamination (dry lamination method). Non-solvent lamination is a new film material on the surface immediately after applying the above-mentioned adhesive heated to room temperature to about 120 ° C on a base film with a roll such as a roll coater heated to room temperature to about 120 ° C. A laminated film can be obtained by laminating.
In the case of the extrusion laminating method, an organic solvent solution of the adhesive is applied to the base film as an adhesion auxiliary agent (anchor coating agent) by a roll such as a gravure roll, and the solvent is dried and cured at room temperature to 140 ° C. After being performed, a laminate film can be obtained by laminating the polymer material melted by the extruder. The polymer material to be melted is preferably a polyolefin resin such as a low density polyethylene resin, a linear low density polyethylene resin, or an ethylene-vinyl acetate copolymer resin.

When the laminate thus obtained is used as a packaging material for food, the thickness of the plastic film, the thickness of the ink layer, and the thickness of the adhesive layer is controlled so that the thickness is 300 μm or less. It is preferable.

Hereinafter, the effects of the present invention will be specifically described using examples and comparative examples, but the present invention is not limited to these examples. In the following description, parts and% indicate parts by weight.

(Production Example 1 Production Example of Aqueous Polyurethane Resin (b-1-1))
1000 parts of polycarbonate polyol “Nipporan N981” (average molecular weight = 1000) manufactured by Nippon Polyurethane Industry Co., Ltd. was dehydrated at 100 ° C. under reduced pressure. Thereafter, the mixture was cooled to 80 ° C., 1000 parts of ethyl acetate was added and sufficiently stirred to dissolve.
Next, 100 parts of 2,2′-dimethylolpropionic acid was added, and then 400 parts of tolylene diisocyanate was added and reacted at 75 ° C. for 5 hours to obtain a polyurethane prepolymer (b-1).
After confirming that the isocyanate value became 1.80 to 1.90%, the mixture was cooled to 40 ° C., neutralized by adding 75 parts of triethylamine, and then dissolved by adding 7000 parts of water. Subsequently, 36 parts of 80% hydrazine hydrazine was added as a chain extender to carry out a chain extension reaction.
Ethyl acetate was removed from the obtained translucent reaction product under reduced pressure at 30 to 60 ° C., water was added to adjust the concentration, and a stable translucent solution having a nonvolatile content of 20% and a Tg of −15 ° C. An aqueous polyurethane resin (b-1-1) which is an aqueous dispersion was obtained.

(Production Example 2 Production Example of Aqueous Polyurethane Resin (b-1-2))
Instead of the polycarbonate polyol in Production Example 1, polytetramethylene ether glycol “PTMG-1000” manufactured by Mitsubishi Chemical Corporation was used in the same manner as in Production Example 1 except that average molecular weight = 1000. An aqueous polyurethane resin (b-1-2) which was a stable translucent aqueous dispersion of 20%, Tg-50 ° C. was obtained.

(Production Example 3 Production Example of Acrylic Emulsion Resin for Comparative Example)
A flask equipped with a stirrer, a thermometer, a dropping funnel, a cooling pipe and a nitrogen gas introduction pipe was charged with 400 parts of ion-exchanged water and 7.5 parts of a surfactant “New Coal 707SF” manufactured by Nippon Emulsifier Co., Ltd. Stirring was started and the temperature was raised to 80 ° C. in a nitrogen stream. A pre-emulsion comprising 75 parts of ion-exchanged water, 41.7 parts of New Coal 707SF, 12.5 parts of 80% methacrylic acid, 300 parts of methyl methacrylate and 190 parts of n-butyl methacrylate was prepared in the dropping funnel. 31.0 parts corresponding to 5% of the above was added. Next, after adding 10.2 parts of a 1.5% aqueous potassium persulfate solution and holding at that temperature for 15 minutes, the remaining 95% of the pre-emulsion and 65.4 parts of a 0.5% aqueous potassium persulfate solution were added. , And dropped from another dropping port over 3 hours. The reaction temperature at this time was kept at 80 ± 3 ° C. After the completion of dropping, the reaction is continued under stirring while maintaining the same temperature range for 2 hours, then cooled and adjusted to pH 8.0 to 9.0 with 14% ammonia water, and the nonvolatile content is 45.0%. An acrylic emulsion resin having a viscosity of 116 mPa · s, a pH of 8.8, and an average particle diameter of 60 nm was obtained.

(Production Example 4 Production Example of Aqueous Resin (b-X1) Production of 67.5 parts of ion-exchanged water and 45 parts of New Coal 707SF in a flask equipped with a stirrer, thermometer, dropping funnel, cooling pipe and nitrogen gas introduction pipe Stirring was started by adding 1028.6 parts of the aqueous polyurethane resin (b-1-1) obtained in Example 1 and 22.5 parts of methyl methacrylate, and the temperature was raised to 80 ° C. in a nitrogen stream. Pre-emulsion consisting of 22.5 parts, Newcol 707SF 31.5 parts, sodium styrenesulfonate 6.3 parts, diacetone acrylamide 1.6 parts, methyl methacrylate 44 parts, n-butyl methacrylate 22 parts and 5% 47.3 parts of an ammonium persulfate aqueous solution was added dropwise from another dropping port over 1 hour, and the reaction temperature was maintained at 80 ± 3 ° C. After the completion of dropping. While maintaining the temperature range for 2 hours, the reaction is continued with stirring, then cooled and adjusted to pH 8.0 to 9.0 with 14% aqueous ammonia, the non-volatile content is 35.4%, and the viscosity is 17 mPa · s. An aqueous resin (b-X1) having a pH of 8.7 and an average particle diameter of 60 nm was obtained.

(Production Example 5 Production Example of Aqueous Resin (b-X2)) A nonvolatile resin was produced in the same manner as in Production Example 4 except that the aqueous polyurethane resin used was changed to the aqueous polyurethane resin (b-1-2) of Production Example 2. An aqueous resin (b-X2) having a content of 35.6%, a viscosity of 21 mPa · s, a pH of 8.9, and an average particle size of 50 nm was obtained.

(Production Example 6 Production Example of Aqueous Resin (b-X3) Using 771.4 parts of aqueous polyurethane resin (b-1-2) of Production Example 2 as the aqueous polyurethane resin to be used, charging ion-exchanged water charged in a flask The same as in Production Example 4 except that the amount was changed to 225 parts and the monomer composition of the pre-emulsion was changed to 3.2 parts diacetone acrylamide, 110.4 parts methyl methacrylate, and 43.9 parts n-butyl methacrylate. Thus, an aqueous resin (b-X3) having a non-volatile content of 35.5%, a viscosity of 30 mPa · s, a pH of 8.5, and an average particle diameter of 50 nm was obtained.

(Production Example 7 Production Example of Aqueous Resin (b-X4) Using 257.1 parts of aqueous polyurethane resin (b-1-1) of Production Example 1 as the aqueous polyurethane resin to be used, charging ion-exchanged water charged into the flask The amount was changed to 225 parts, and the monomer composition of the pre-emulsion was 67.5 parts ion-exchanged water, 7.2 parts diacetone acrylamide, 85.5 parts styrene, 122.4 parts methyl methacrylate, 2-ethylhexyl acrylate Except for changing to 118.8 parts and 4.5 parts of 80% methacrylic acid, in the same manner as in Production Example 4, an aqueous solution having a non-volatile content of 45.8%, a viscosity of 810 mPa · s, a pH of 8.5, and an average particle diameter of 55 nm Resin (b-X4) was obtained.

(Preparation Example 1 Pigment Dispersion (a-1) Cyan Pigment Dispersion)
Stir 20 parts of cyan pigment “FANTOGEN BLUE FSJ-SD” manufactured by DIC Corporation, 30 parts of “Disperbyk-190” manufactured by Big Chemie Japan Co., Ltd. as a pigment dispersant, 5 parts of isopropyl alcohol, and 45 parts of pure water. Mixed. Next, after the kneaded meat was dispersed using a bead mill, coarse particles were removed by a centrifugal separator, and pure water was added to obtain a cyan pigment dispersion (a-1) adjusted to a pigment concentration of 15%.

(Preparation Example 2 Pigment Dispersion (a-2) Magenta Pigment Dispersion)
20 parts of magenta pigment “Fastogen Super Magenta RTS” manufactured by DIC Corporation, 30 parts of “Disperbyk-190” manufactured by Big Chemie Japan Co., Ltd. as a pigment dispersant, 5 parts of isopropyl alcohol, and 45 parts of pure water are mixed. did. Next, after the kneaded meat was dispersed using a bead mill, coarse particles were removed by a centrifugal separator, and pure water was added to obtain a magenta pigment dispersion (a-2) adjusted to a pigment concentration of 15%.

(Preparation Example 3 Pigment Dispersion (a-3) Yellow Pigment Dispersion)
20 parts of yellow pigment “Fast Yellow 7413” manufactured by Sanyo Dye Co., Ltd., 30 parts of “Disperbyk-190” manufactured by Big Chemie Japan Co., Ltd. as a pigment dispersant, 5 parts of isopropyl alcohol, and 45 parts of pure water are mixed with stirring. did. Next, after the kneaded meat was dispersed using a bead mill, coarse particles were removed by a centrifugal separator, and pure water was added to obtain a yellow pigment dispersion (a-3) adjusted to a pigment concentration of 15%.

(Preparation Example 4 Pigment dispersion (a-4) Black pigment dispersion)
20 parts of black pigment “Carbon Black # 960” manufactured by Mitsubishi Chemical Corporation, 30 parts of “Disperbyk-190” manufactured by Big Chemie Japan Co., Ltd., 5 parts of isopropyl alcohol, and 45 parts of pure water as a pigment dispersant Mixed. Next, after the kneaded meat was dispersed using a bead mill, coarse particles were removed by a centrifugal separator, and pure water was added to obtain a black pigment dispersion (a-4) adjusted to a pigment concentration of 15%.

(Preparation Example 5 Pigment dispersion (a-5) White pigment dispersion)
40 parts of white pigment “JR-804” manufactured by Teika Co., Ltd., 10 parts of “Disperbyk-190” manufactured by Big Chemie Japan Co., Ltd. as a pigment dispersant, 5 parts of isopropyl alcohol, and 45 parts of pure water are mixed with stirring. A white pigment dispersion (a-5) was prepared by dispersing the kneaded meat using a bead mill and then adding pure water to adjust the pigment concentration to 38%.

(Solid content measurement method)
The weight of the evaporating dish (A), the total weight of the pigment dispersion dropped onto the evaporating dish (B), and the evaporating dish on which the pigment dispersion was dropped was allowed to stand in a dryer heated to 100 ° C. for 2 hours to evaporate water. The total amount (C) of the pigment dispersion and the evaporating dish that had been solidified was measured, and the solid content was determined by the following formula.

(Example 1 to Example 12 Ink adjustment)
According to the formulation shown in Tables 1 and 2, a mixed solution obtained by stirring and mixing was prepared. The mixture was filtered through a 0.5 μm filter to obtain water-based inkjet recording inks (1) to (12) for laminating.

(Comparative Examples 1 to 5 Ink Adjustment)
According to the formulation shown in Table 3, a mixed solution obtained by stirring and mixing was prepared. The mixture was filtered through a 0.5 μm filter to obtain water-based inkjet recording inks (H1) to (H5) for laminating.

Aqueous gravure ink (manufactured by DIC Graphics, Inc., Marine Plus G R507 primary color indigo (C1)) 100 parts, ethanol 21 parts, and pure water 9 parts were mixed and stirred to obtain an aqueous inkjet recording ink (H7) for laminating.

[Evaluation of the physical properties]
(Storage stability test)
Viscosity of inks of Examples 1 to 12 and Comparative Examples 1 to 5 was measured with an E-type viscometer (TV-20, manufactured by Toki Sangyo Co., Ltd.), and a particle size distribution meter (Microtrac UPA-150, manufactured by Nikkiso Co., Ltd.) After measuring the 50% particle size, the sample was placed in a glass sample bottle, and the lid was closed and sealed, and left in a constant temperature bath at 60 ° C. After 30 days, the sample bottle was taken out of the thermostatic chamber, and the viscosity and 50% particle size of the ink were measured. Evaluation was judged as follows.
○: Change rate of viscosity / 50% particle size is less than 10% Δ: Change rate of viscosity / 50% particle size is 10% or more and less than 20% ×: Change rate of viscosity / 50% particle size is 20% or more, or Ink separation occurs

(Discharge test)
An ink jet printer having a piezo head with a maximum drive frequency of 7.6 KHz and a resolution of 360 DPI (360 dots per 25.4 mm) was evaluated by ejecting onto a PET film (Ester E-5100 manufactured by Toyobo Co., Ltd.). .
Evaluation was judged as follows.
After printing equivalent to 10 sheets of A4 solid, a check pattern is printed and non-ejection nozzles are evaluated. ○: Non-ejection nozzles less than 1% Δ: Non-ejection nozzles 1% to 5% x: Non-ejection nozzles 5% or more

(Lamination test)
(1) Adjustment of adhesive 10 parts of adhesive “Dick Dry LX-401” manufactured by DIC Graphics, 10 parts of curing agent “SP-60” manufactured by DIC Graphics, and 60 parts of ethyl acetate as curing agents The mixture was stirred and the adhesive was adjusted.

(2) Laminate production method A PET film (Ester E-5100 manufactured by Toyobo Co., Ltd.) and an OPP film (FOR30 manufactured by Futamura Chemical Co., Ltd.) used for food packaging materials are coated with a bar coater No. In Example 4, the inks of Examples 1 to 12 and Comparative Examples 1 to 5 were applied and allowed to stand for 3 minutes in a dryer heated to 100 ° C. to dry the ink.
After the ink dries, the bar coater no. 10 was applied with the adhesive adjusted in the above (1), the whole was applied for 10 seconds with hot air of a dryer, the adhesive was dried, and a CPP film (PYLEN P-1128 made by Toyobo Co., Ltd.) was covered, The roll temperature was pasted with a laminator set at 40 ° C. The laminated product was left in a constant temperature bath at 40 ° C. for 48 hours to cure the adhesive.

(3) Laminate strength test The laminate of (2) in which the adhesive was sufficiently cured was cut into a length of 200 mm and a width of 15 mm, and the bonded portion was peeled off by about 30 mm. The slightly peeled portion was further peeled with a tensile tester (TENSILON RTM-25 manufactured by Orientec Co., Ltd.), and the adhesive strength of the laminate layer was measured.
Evaluation was judged as follows.
○: Strength when peeling a laminated product is 1 N / 15 mm or more Δ: Strength when peeling a laminated product is 0.5 N / mm to less than 1 N / 15 mm X: Strength when peeling a laminated product Less than 0.5N / 15mm

(4) Anti-blocking test PET coater (Ester E-5100 manufactured by Toyobo Co., Ltd.) and OPP film (FOR30 manufactured by Futamura Chemical Co., Ltd.) used for food packaging are coated with a bar coater no. The ink was applied at 4 and left in a dryer heated to 100 ° C. for 1 minute to dry the ink. After the ink was dried, the printing surface and the film back surface were overlapped, and a pressure of 9.8 × 10 ⁴ Pa (1 kgf / cm ² ) was applied thereto. After leaving for 24 hours, it was peeled off and evaluated for blocking resistance.
Evaluation was judged as follows.
○: There is no setback on the back of the film when the stacked film is peeled. Δ: About 10% setback occurs on the back of the film when the stacked film is peeled. ×: The back of the film when the stacked film is peeled off. Overset of about 10% occurs

Tables 1 to 3 show ink formulations, and Tables 4 to 6 show physical property evaluation results.

From this result, the water-based inkjet recording ink for laminating of the example obtained excellent storage stability, dischargeability, and laminate strength.
Comparative Examples 1 to 4 are examples in which (b) an aqueous resin is not used, but it was impossible to achieve both laminate strength and blocking resistance.
Comparative Example 5 is an example in which gravure ink is applied to inkjet ink, but ejection was not possible.

[Manufacturing Method of Multicolored Printed Laminate]
(Example 13)
PET film (Toyobo Co., Ltd.) used as a packaging material for food in an ink jet printer having a piezo head having the maximum driving frequency of 7.6 KHz and resolution of 360 DPI (360 dots per 25.4 mm). Ester E-5100), OPP film (FOR30, FORMURA CHEMICAL CO., LTD.) Was discharged onto the dryer and allowed to stand in a dryer heated to 100 ° C. for 1 minute to dry the ink. After the ink of Example 1 was dried, the ink of Example 7 was ejected and dried in the same manner as in Example 1, and the same operation was performed for the inks of Examples 8, 9, and 10 for each color ink. A multicolored print was produced. In accordance with the laminating test method, a bar coater no. After the adhesive was applied and cured using No. 10, the laminate strength was measured. As a result, the evaluation was good.

Claims (8)

1. (A) a pigment, and (b) a water-based inkjet recording ink for laminating containing an aqueous resin,
   The aqueous resin (b) includes an aqueous polyurethane resin (b-1) produced through a step of reacting a chain extender comprising a hydrazine derivative, and a carbonyl group or amide group-containing acrylic copolymer (b-2). A water-based inkjet recording ink for laminating, characterized in that it is a water-based resin.
2. The (b) aqueous resin was obtained by neutralizing a urethane prepolymer obtained by reacting a diisocyanate and a glycol containing a carboxylic acid group-containing glycol, and chain-extending with a hydrazine derivative. The laminating process according to claim 1, which is an aqueous resin obtained by polymerizing a radical polymerizable acrylic monomer containing a carbonyl group-containing monomer or an amide group-containing monomer in the presence of the aqueous polyurethane resin (b-1). Water-based inkjet recording ink.
3. The aqueous inkjet recording ink for laminating according to claim 1 or 2, wherein the aqueous resin (b) is resin particles having an average particle diameter of 10 to 100 nm.
4. The water-based inkjet recording for laminate processing according to any one of claims 1 to 3, wherein the resin solid content (%) of the (b) aqueous resin is 1.0 to 10.0% by weight based on the total amount of the ink. ink.
5. The laminate according to any one of claims 1 to 4, wherein a solid content weight ratio of the urethane resin and the acrylic resin in the (b) aqueous resin is (A) / (B) = 95/5 to 5/95. Water-based inkjet recording ink for processing.
6. A step of forming a printing layer on a non-absorbent substrate by an inkjet recording method using the water-based inkjet recording ink for laminating according to any one of claims 1 to 5, and adhesion onto the printing layer The manufacturing method of the laminated body characterized by having the process of forming a layer, and the process of laminating a sealant film layer on the said adhesive layer surface.
7. The method for manufacturing a laminate according to claim 6, wherein the thickness of the laminate is 300 μm or less.
8. The method for producing a laminate according to claim 6 or 7, wherein the non-absorbing substrate is a plastic film.