JP6731707B2 - Printing ink composition for laminating and easily tearable laminate - Google Patents

Description

TECHNICAL FIELD The present invention relates to a printing ink composition for laminating and an easily tearable laminate obtained by printing the printing ink for laminating on a substrate film, applying an adhesive, and laminating a sealant film.

Packaging materials using various plastic films are used for foods, confectionery, household goods, pet foods, etc. because of their functions such as designability, economic efficiency, content protection, and transportability. In addition, many packaging materials are subjected to gravure printing or flexographic printing for the purpose of imparting a design property and a message property that appeal to consumers.
Then, in order to obtain a packaging material for use, surface printing is printed on the surface of the base material film of the packaging material, or an adhesive or an anchor agent is applied to the printed surface of the base material film of the packaging material, if necessary, Back printing is performed by laminating the film.
In back-printing, after color ink and white ink are sequentially printed on various films such as polyester, nylon, aluminum foil, etc., a dry lamination process using an adhesive or an anchor coating agent is applied on the printed layer of the white ink. A polyethylene film, a polypropylene film, or the like is laminated for the purpose of heat sealing by the used extrusion lamination process or the like (see, for example, Patent Document 1).

After that, the laminated body is used as a laminated bag for food such as sweets, soup, and miso soup. These laminated bags are opened manually by a human to retrieve the contents. Here, if the tearability is poor, it is necessary to apply excessive force at the time of opening, and further, there is a problem that the content is spilled in an unintended direction, resulting in spilling of the content, so good tearability is required.
In particular, the area where the ink is printed tends to be inferior in tearability because the bonding force between the ink layer and the adhesive layer is inferior to that in the non-character portion.
As a means for improving the tearability, it is known that the tearability is improved by hardening the laminating adhesive layer (for example, see Patent Document 2). However, the ink portion and the ink are not printed. When the character portions are mixed, the non-character portion becomes too hard when the adhesive layer is hard enough to tear at the ink portion, and conversely, when the adhesive layer is aligned with the non-character portion, the tearability at the ink portion becomes poor.

In order to solve this problem, the ink layer contains a curing agent having two or more functional groups capable of reacting with the same functional group of the ink layer and the adhesive layer, and the ink layer has a functional group in the molecule. It has been proposed to be a layer formed from a composition comprising a compound (a1) having only two or more hydroxyl groups as a group and a curing agent that reacts with the hydroxyl groups (see, for example, Patent Document 3). In the examples, the solid content ratio of the polyfunctional isocyanate curing agent to the polyurethane resin contained in the ink layer is very low, that is, polyurethane resin:polyfunctional isocyanate curing agent=1:0.25, so the tearability is slightly improved. However, there are still problems such as feeling resistance when tearing.
Further, the ink layer using such a compound is not sufficiently good in color developability.

Japanese Patent Laid-Open No. 5-97959 JP, 2008-274061, A JP2012-125978A

An object of the present invention is to print a printing ink composition for lamination that can exhibit good color development and easy tearability, and after printing the printing ink for lamination on a base film, apply an adhesive, and laminate a sealant film. Another object of the present invention is to provide an easily tearable laminated body.

As a result of intensive studies to solve the above problems, the inventors of the present invention have invented the following printing ink composition for laminate and laminate.
The present invention is (1) a printing ink composition for laminating containing a pigment, a binder resin, a polyfunctional isocyanate compound as a curing agent, and an organic solvent, wherein the binder resin reacts with an isocyanate group of the polyfunctional isocyanate compound. Is a polyurethane resin having a possible reactive group, and the solid content ratio of the polyurethane resin and the curing agent is polyurethane resin:curing agent=1:0.35-0.9 Ink composition.
(2) The polyurethane resin has (1) at least one of a primary amino group, a secondary amino group, and a tertiary amino group at the terminal, and a hydroxyl group-containing polyurethane resin and/or ( 2) A printing ink composition for laminating according to (1) above, which is a polyurethane resin having at least one of a primary amino group, a secondary amino group and a tertiary amino group at the end. Stuff.
(3) The printing ink composition for laminating according to the above (1) or (2), wherein the polyfunctional isocyanate compound is a trifunctional or higher functional isocyanate compound.
(4) The printing ink composition for laminating according to any one of (1) to (3) above, wherein the organic solvent is a mixed solvent of an ester organic solvent and an alcohol organic solvent.
(5) An easily tearable laminate in which a printing layer comprising the printing ink for laminating according to any one of (1) to (4), an adhesive layer having a hydroxyl group, and a sealant film are sequentially laminated on a substrate film. body.
(6) After being printed with the printing ink for laminating according to any one of (1) to (4) on the base film, an adhesive having a hydroxyl group is applied, and a sealant film is laminated to obtain the product. The easily tearable laminate according to (5) above.

As a binder resin used in the printing ink composition for lamination of the present invention, a polyurethane resin having a reactive group capable of reacting with an isocyanate group of a polyfunctional isocyanate compound, and a solid content of a polyfunctional isocyanate compound, a polyurethane resin and a curing agent as a curing agent. The polyurethane resin has a reactive group capable of reacting with the isocyanate group of the polyfunctional isocyanate compound when used in such a range that the content ratio is polyurethane resin:curing agent=1:0.35-0.9. Therefore, the binding agent between the printing layer and the adhesive layer can be increased by reacting with the curing agent in the printing ink composition for lamination and the isocyanate group of the adhesive layer, and the polyurethane resin:curing agent=1: Since a large amount of the curing agent is used so as to be 0.35 to 0.9, it is considered that the ink layer becomes hard and tearability becomes good. In particular, as the polyurethane resin, (1) a polyurethane resin having at least one of a primary amino group, a secondary amino group and a tertiary amino group at the terminal and having a hydroxyl group, and/or (2) A polyurethane resin having at least one of a primary amino group, a secondary amino group, and a tertiary amino group at the terminal, a polyfunctional isocyanate compound as a curing agent, a polyurethane resin, and a solid content ratio of the curing agent. However, when the polyurethane resin:curing agent=1:0.35-0.9 is used in a range such that the polyurethane resin has a primary amino group, a secondary amino group and a tertiary amino group at the end. Since it has one or more of them, it has a polyurethane resin viscosity that can be adjusted to an appropriate viscosity range as a printing ink, and also has good pigment dispersibility, so the resin content in the printing ink composition for lamination is high. can do. Further, since the polyurethane resin has a hydroxyl group, it can react with the curing agent in the printing ink composition for lamination and the isocyanate group of the adhesive layer to increase the binding force between the printing layer and the adhesive layer. In addition, since a large amount of the curing agent is used such that polyurethane resin:curing agent=1:0.35 to 0.9, it is considered that the ink layer becomes hard and tearability becomes good. Further, since the pigment dispersibility is good, it is considered that the color developability is also good.

Hereinafter, the printing ink composition for laminating and the easily tearable laminate of the present invention will be described in more detail.
First, the printing ink composition for lamination of the present invention will be described.
<Pigment>
As the pigment that can be used in the present invention, various inorganic pigments and/or organic pigments that are generally used in printing inks can be used.
As the inorganic pigment, titanium oxide, red iron oxide, antimony red, cadmium yellow, cobalt blue, dark blue, ultramarine blue, carbon black, colored pigments such as graphite, silica, calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide, talc, etc. Other extender pigments can be mentioned.
Examples of organic pigments include soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments, condensed polycyclic pigments, and the like.
The content of the pigment in the printing ink composition for laminating of the present invention is preferably in the range of 5 to 60 mass% in the ink composition.
When the content of the pigment in the printing ink composition for laminating is less than the above range, the coloring power as the ink composition is reduced, and when it is more than the above range, the viscosity of the ink composition becomes high and the printed matter becomes dirty. It will be easier.

<Binder resin>
As the binder resin, a polyurethane resin having a reactive group capable of reacting with an isocyanate group of a polyfunctional isocyanate compound used as a curing agent described below can be used.
The polyurethane resin having a reactive group capable of reacting with the isocyanate group of the polyfunctional isocyanate compound has at least one of a primary amino group, a secondary amino group and a tertiary amino group and/or a hydroxyl group at the terminal. It is possible to use a polyurethane resin having, in particular, (1) a polyurethane resin having at least one kind of a primary amino group, a secondary amino group and a tertiary amino group at a terminal and having a hydroxyl group. And/or (2) a polyurethane resin having at least one of a primary amino group, a secondary amino group and a tertiary amino group at the terminal is preferable. Such a polyurethane resin is highly functional with a polyfunctional diisocyanate compound. A urethane prepolymer was synthesized by a reaction with a molecular diol compound, and (1) both ends of the resulting urethane prepolymer were selected from primary amino groups, secondary amino groups, and tertiary amino groups. By reacting with an amine compound containing one or more polyamine compounds and an amine compound having a hydroxyl group, (2) both ends of a primary amino group, a secondary amino group and a tertiary amino group It is obtained by reacting an amine compound containing one or more polyamine compounds.
At this time, the urethane prepolymer and (1) an amine compound containing a polyamine compound whose both ends are one or more of a primary amino group, a secondary amino group and a tertiary amino group, and a hydroxyl group (2) reacting an amine compound containing a polyamine compound having at least one of a primary amino group, a secondary amino group and a tertiary amino group at both ends As the method, (1) a method of chain-extending the urethane prepolymer with a chain extender and then stopping the reaction with a reaction terminator, and (2) a chain extension of the urethane prepolymer with a chain extender and a reaction terminator Examples thereof include a method of reacting the reaction terminations at the same time.

(Polyfunctional diisocyanate compound)
Examples of the polyfunctional diisocyanate compound that can be used to obtain the binder resin include aromatic diisocyanate compounds such as tolylene diisocyanate, 1,4-cyclohexane diisocyanate, alicyclic diisocyanate compounds such as isophorone diisocyanate, and hexamethylene diisocyanate. The aliphatic diisocyanate compound and the araliphatic diisocyanate compound such as α,α,α′,α′-tetramethylxylylene diisocyanate can be used alone or in combination of two or more. Of these, an alicyclic diisocyanate compound, an aliphatic diisocyanate compound and an araliphatic diisocyanate compound are more preferable. Furthermore, a trifunctional or higher functional isocyanate compound can be used.

(Polymer diol compound)
Examples of the polymer diol compound that can be used to obtain the binder resin include polyalkylene glycols such as polyethylene glycol and polypropylene glycol, polyether diol compounds such as ethylene oxide of bisphenol A and alkylene oxide adducts such as propylene oxide, One or more dibasic acids such as adipic acid, sebacic acid, and phthalic anhydride, and ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol. One or more kinds of various polymer diol compounds such as polyester diol compounds such as polyester diols and polycaprolactone diols obtained by condensation reaction of one or more kinds of glycols such as ..
Further, in addition to the above-mentioned polymer diol compound, alkanediol such as 1,4-pentanediol, 2,5-hexanediol, 3-methyl-1,5-pentanediol, ethylene glycol, propylene glycol, 1,4- Low molecular weight diol compounds such as butanediol and 1,3-butanediol can be used alone or in combination of two or more.
In addition, in a mixture system of an ester solvent and an alcohol solvent, the use of a polyether diol compound as the polymer diol compound tends to increase the solubility of the obtained polyurethane resin, and thus it can be widely used according to the required performance. It is preferable in that the ink can be designed.
Further, the use ratio of the organic diisocyanate compound and the polymer diol compound is such that the equivalent ratio of isocyanate group:hydroxyl group (isocyanate index) is usually 1.2:1 to 3.0:1, more preferably 1.3: The range is 1 to 2.0:1. If the above-mentioned isocyanate index is smaller than 1.2, it tends to be a flexible polyurethane resin, and when blocking resistance and the like when printing ink is low, it may be preferable to use it in combination with another hard resin. is there.

(Chain extender)
As the chain extender that can be used to obtain the binder resin, known chain extenders used in polyurethane resins as binders for inks can be used, such as ethylenediamine, propylenediamine, tetramethylenediamine, and hexamethylene. Aliphatic diamines such as diamines, isophoronediamine, alicyclic diamines such as 4,4′-dicyclohexylmethanediamine, polyamines such as diethylenetriamine and triethylenetetratriamine, aromatic diamines such as toluylenediamine, xylenediamine Diamines having a hydroxyl group such as araliphatic diamines, N-(2-hydroxyethyl)ethylenediamine, N-(2-hydroxyethyl)propylenediamine, N,N′-di(2-hydroxyethyl)ethylenediamine, and the like. Examples thereof include diol compounds such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol and triethylene glycol.

(Reaction terminator)
Examples of the reaction terminator that can be used to obtain the binder resin include aliphatic diamines such as tramethylenediamine and hexamethylenediamine, alicyclic diamines such as isophoronediamine and 4,4′-dicyclohexylmethanediamine, Polyamines such as diethylenetriamine and triethylenetetratriamine, aromatic diamines such as toluylenediamine, araliphatic diamines such as xylenediamine, N-(2-hydroxyethyl)ethylenediamine, N-(2-hydroxyethyl)propylene. Diamines having hydroxyl groups such as diamines and N,N'-di(2-hydroxyethyl)ethylenediamine, and the like, polyamine compounds having primary amino groups at both ends, and monoalkylamines such as n-propylamine and n-butylamine Examples thereof include dialkylamines such as di-n-butylamine, alkanolamines such as monoethanolamine and diethanolamine, and monoalcohols such as ethanol.
In order to obtain a polyurethane resin having a primary amino group and/or a secondary amino group at both ends, a polyamine having a primary amino group and/or a secondary amino group at both ends is used as a reaction terminator. Examples of the polyamine having a primary amino group and/or a secondary amino group at both ends include aliphatic diamines such as ethylenediamine, propylenediamine, tetramethylenediamine, and hexamethylenediamine, isophoronediamine, 4,4′- Alicyclic diamines such as dicyclohexylmethanediamine, polyamines such as diethylenetriamine and triethylenetetratriamine, aromatic diamines such as toluylenediamine, araliphatic diamines such as xylenediamine, N-(2-hydroxyethyl) Diamines having a hydroxyl group such as ethylenediamine and N-(2-hydroxyethyl)propylenediamine, and the like, and among these, polyamines having a primary amino group such as diethylenetriamine and triethylenetetratriamine are preferable.
To obtain a polyurethane resin having a hydroxyl group, a compound having a hydroxyl group is used as a chain extender and/or a reaction terminator. It is preferable to use a compound having a hydroxyl group as both the chain extender and the reaction terminator. Examples of the chain extender include diamines having a hydroxyl group such as N-(2-hydroxyethyl)ethylenediamine, N-(2-hydroxyethyl)propylenediamine and N,N'-di(2-hydroxyethyl)ethylenediamine. it can. As the reaction terminator, diamines having a hydroxyl group such as N-(2-hydroxyethyl)ethylenediamine, N-(2-hydroxyethyl)propylenediamine, N,N'-di(2-hydroxyethyl)ethylenediamine, monoethanol. Examples thereof include alkanolamines having a hydroxyl group such as amine and diethanolamine.

In the present invention, an organic diisocyanate can be obtained using the above-mentioned materials by employing a known method for producing a polyurethane resin. Further, when the molecular weight, chemical structure, or equivalent ratio of each component is different, the hardness of the resulting polyurethane resin is also different. Therefore, it is possible to appropriately select these components and combine them to adjust the printability and laminating suitability. Is.
The content of the binder resin is preferably 5 to 15 mass% in terms of solid content in the printing ink composition for lamination during printing. If the content of the binder resin is out of the range, the tearability tends to decrease.
The weight average molecular weight of the polyurethane resin in the printing ink composition for lamination of the present invention is preferably 10,000 to 70,000, and more preferably 20,000 to 40,000.
Further, as other binder resin, cellulose resin, acrylic resin, polyamide resin, adhesive resin or the like can be supplementarily added.

<Curing agent>
A polyfunctional polyisocyanate compound can be used as the curing agent. Specifically, biuret, isocyanurate, adduct, bifunctional polyfunctional isocyanate compound, isophorone diisocyanate can be used, and 24A-100, 22A-75, TPA-100, TSA-100, TSS-100, TAE-100. , TKA-100, P301-75E, E402-808, E405-70B, AE700-100, D101, D201, A201H (manufactured by Asahi Kasei Corporation), Mitec Y260A (manufactured by Mitsubishi Chemical Corporation), Coronate CORONATE HX, Coronate CORONATE HL, Coronate CORONATE L (manufactured by Nippon Polyurethane Co., Ltd.), Desmodur N75MPA/X (manufactured by Bayer Co., Ltd.) and the like can be exemplified. Of these, isophorone diisocyanate or its adduct is preferable. Furthermore, a trifunctional or higher functional isocyanate compound can also be used.
The amount of the curing agent used is such that the mass ratio of the contents of the polyurethane resin and the curing agent is in the range of polyurethane resin:curing agent=1:0.35-0.9 from the viewpoint of tearability. , Polyurethane resin:hardening agent=1:0.4 to 0.8, more preferably polyurethane resin:hardening agent=1:0.48 to 0.75.

<Organic solvent>
As the organic solvent used in the printing ink composition for lamination, toluene, ketone-based organic solvents (for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), ester-based organic solvents (for example, methyl acetate, ethyl acetate, n-propyl acetate) are used. , N-butyl acetate, isobutyl acetate, etc.), alcoholic organic solvents (eg, methanol, ethanol, n-propanol, isopropanol, butanol, etc.), and hydrocarbon solvents (toluene, methylcyclohexane, etc.) can be used.
In addition, in consideration of recent environmental problems and the printability and drying properties of the ink, among others, as an organic solvent of the printing ink composition for lamination at the time of printing, an ester organic solvent and an alcohol organic solvent are used. The mixed organic solvent should be in the range of ester organic solvent/alcohol organic solvent=50/50 to 95/5, preferably ester organic solvent/alcohol organic solvent=60/40 to 85/15. Preference is given to using.
Further, from the viewpoint of the printability of the ink, it is preferable that the printing ink composition for laminating at the time of printing contains 5 mass% or more, preferably 15 mass% or more of propyl acetate.

<Additive>
The organic solvent-based gravure printing composition may further contain various additives such as a tackifier, a crosslinking agent, a lubricant, an anti-blocking agent, an antistatic agent, and a surfactant.

<The manufacturing method of the printing ink composition for lamination of this invention>
The printing ink composition for laminating of the present invention is produced by using various materials other than the above-mentioned curing agent by using various commonly used dispersing/kneading apparatuses, and the content of each solid content material and By adjusting the combination of polyurethane resin and organic solvent, etc., after setting the viscosity to 10 to 1000 mPa·s, from the viewpoint of experience stability, a curing agent is added at the time of printing and printing is performed at the ambient temperature during printing. To obtain an appropriate number of seconds depending on the conditions, specifically add an organic solvent and stir until the outflow seconds of Zahn Cup No. 3 is 12 to 23 seconds, preferably about 14 to 16 seconds in high speed printing. Can be obtained.

<Easy tearable laminate>
Next, the base film is printed with a printing ink for laminating, and then a polyester-based adhesive having a hydroxyl group and an adhesive containing an isocyanate-based adhesive containing an isocyanate group are applied, and a sealant film is laminated. The easily tearable laminate will be described.

(Base film)
The substrate film of the easily tearable laminate of the present invention is not particularly limited, and a polyolefin film such as polyethylene and polypropylene, a polyester film such as polyethylene terephthalate, polylactic acid and polycaprolactone, a plastic film for various printing such as nylon and vinylon. Can be used.

(Printing ink composition for lamination)
As the printing ink composition for laminating, the printing ink composition for laminating described above can be used.

(adhesive)
Conventionally, an adhesive having a hydroxyl group, which has been used in extrusion laminating and dry laminating, can be used. For example, a polyester-based adhesive having a hydroxyl group and an adhesive containing an isocyanate-based adhesive containing an isocyanate group can be exemplified.
Specifically, as an adhesive (anchor coat agent) used in extrusion lamination processing, A-3210/A-3070, A-3210/A3072, A-3210/A-3075 (manufactured by Mitsui Chemicals, Inc.) , Secedane 2710A/Secedane 2810C(T), Secedane 2730A/Secedine 2730B, Secedane 2710A/Secedane 2710C (manufactured by Dainichiseika Kogyo KK), LX-500, LX-901, LX747A, etc. As the agent, Deck Dry LX-401A, 75A, 719, 703VL, 500, 510 and the like (manufactured by DIC Graphic, Dick Dry is a registered trademark of DIC Graphics), Takelac/Takenate A-909/A-5, A -977/A-92, A-606/A-50, A-515/A-50, A-626/A-50, A-525/A-52, A-666/A-65, etc. (Mitsui Chemicals) Company), RU-77, 771, 3600, 3900, etc. (manufactured by Rock Paint).

(Sealant film)
For the sealant film, a conventionally used resin such as low-density polyethylene, LLDPE, ethylene-vinyl acetate copolymer, or polypropylene can be used as the molten resin used when the laminating means by dry laminating is adopted.
As the plastic film used for extrusion lamination by laminating the formed films, conventionally used films such as unstretched plastic films (eg, unstretched polyethylene film, unstretched polypropylene film, etc.) can be used. ..

<Easily tearable laminated body and easily tearable laminated bag>
The easily tearable laminate and the easily tearable laminated bag of the present invention will be described.
First, a desired pattern, characters or the like is printed on the above-mentioned printing substrate by using a general gravure printing method, a flexographic printing method or the like with the printing ink composition for lamination of the present invention.
Lamination is performed by laminating a heat-fusible polymer called a sealant on the obtained printed matter. Two methods are mainly used for this laminating process.
The first is printing with a printing ink composition for laminating, and after or before curing the printed portion with a curing agent, an adhesive (also called an anchor coating agent) is applied to the surface of the obtained printing layer. ) Is applied, and then the heat-fusible polymer is used as a molten resin, which is laminated by extrusion laminating. The extrusion laminating method is performed by applying an adhesive (for example, a polyester-based adhesive having a hydroxyl group and an isocyanate-containing adhesive containing an isocyanate group) on the surface of the printed layer, and then applying a known extrusion method. It is formed by laminating molten resins by a laminating machine. Further, the molten resin may be used as an intermediate layer, and another material may be further laminated to form a sandwich. In addition, it is preferable to use an isocyanate-based anchor coating agent as an adhesive, because the adhesive strength is superior to that of an imine-based anchor coating agent.
The second is printing with a printing ink composition for laminating, and after the printed portion is cured with a curing agent or before the adhesive is applied to the surface of the printed layer (for example, a polyester-based resin having a hydroxyl group). This is a dry lamination process in which an unstretched plastic film is laminated after applying an adhesive and an adhesive containing an isocyanate-based adhesive containing an isocyanate group. In particular, a metal foil used for retort applications can be laminated using a film composed of multiple layers sandwiched in advance.
The easily tearable laminate obtained by these methods is finally sealed with the sealant surfaces by a heat sealer or the like to form an easily tearable laminated bag.
In addition, as a matter common to these two methods, when printing is performed with a printing ink composition for lamination, and an adhesive is applied after the printing portion is cured with a curing agent, the printing ink for lamination is used. The composition and the adhesive may be cured by functional groups different from each other, that is, may be cured by different curing mechanisms, and a curing agent having the same functional group may be used. As a result, it becomes possible to select a more appropriate combination of the printing ink composition for laminating and the adhesive.
On the other hand, when printing is performed with the printing ink composition for lamination and an adhesive is applied before curing the printed part with a curing agent, the printing ink composition for lamination and the adhesive are the same as each other. It is also possible to use hardeners on which functional groups act.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples. Unless otherwise specified, "%" means "mass%" and "part" means "part by mass".

(Manufacture of polyurethane resin varnish)
Polyurethane resin varnish A production example (with terminal primary amino group and terminal hydroxyl group)
In a four-necked flask equipped with a stirrer, a cooling pipe and a nitrogen gas introduction pipe, 100 parts by mass of 3-methyl-1,5-pentylene adipatediol having an average molecular weight of 2000, 100 parts by mass of polypropylene glycol having an average molecular weight of 2000, and 44.4 parts by mass of isophorone diisocyanate was charged and reacted at 100 to 105° C. for 6 hours while introducing nitrogen gas. After cooling to near room temperature, 521 parts by mass of ethyl acetate and 92 parts by mass of isopropyl alcohol were added, 15.6 parts by mass of isophoronediamine was added to extend the chain, and 0.31 parts by mass of monoethanolamine was further added to react. Then, 1.68 parts by mass of isophoronediamine and 0.17 parts by mass of diethylenetriamine were added to stop the reaction to obtain a polyurethane resin varnish A (solid content 30% by mass, viscosity 250 mPa·s/25° C.).

Polyurethane resin varnish B production example (with primary amino group at the terminal, intramolecular and terminal hydroxyl groups)
In a four-necked flask equipped with a stirrer, a cooling pipe and a nitrogen gas introduction pipe, 100 parts by mass of 3-methyl-1,5-pentylene adipatediol having an average molecular weight of 2000, 100 parts by mass of polypropylene glycol having an average molecular weight of 2000, and 35.5 parts by mass (0.16 mol) of isophorone diisocyanate and 4.7 parts by mass (0.04 mol) of N-(2-hydroxyethyl)propylenediamine were charged, and 6 at 100 to 105° C. while introducing nitrogen gas. Reacted for hours. After cooling to near room temperature, 521 parts by mass of ethyl acetate and 92 parts by mass of isopropyl alcohol were added, 15.6 parts by mass of isophoronediamine was added to extend the chain, and 0.31 parts by mass of monoethanolamine was further added to react. Then, 1.68 parts by mass of isophoronediamine and 0.17 parts by mass of diethylenetriamine were added to stop the reaction to obtain a polyurethane resin varnish B (solid content 30% by mass, viscosity 250 mPa·s/25° C.).

Polyurethane resin varnish C production example (terminal primary amino group, terminal hydroxyl group)
In a four-necked flask equipped with a stirrer, a cooling pipe and a nitrogen gas introduction pipe, 100 parts by mass of 3-methyl-1,5-pentylene adipatediol having an average molecular weight of 2000, 100 parts by mass of polypropylene glycol having an average molecular weight of 2000, and 44.4 parts by mass of isophorone diisocyanate was charged and reacted at 100 to 105° C. for 6 hours while introducing nitrogen gas. After allowing to cool to near room temperature, 523 parts by mass of ethyl acetate and 92 parts by mass of isopropyl alcohol were added, 13.6 parts by mass of isophoronediamine was added to extend the chain, and 0.49 parts by mass of monoethanolamine was further added to react. Then, 4.76 parts by mass of isophoronediamine and 0.41 parts by mass of diethylenetriamine were added to stop the reaction, and a polyurethane resin varnish C (solid content 30% by mass, viscosity 200 mPa·s/25° C.) was obtained.

Polyurethane resin varnish D production example (primary amino group at the end, no hydroxyl group)
In a four-necked flask equipped with a stirrer, a cooling pipe and a nitrogen gas introduction pipe, 100 parts by mass of 3-methyl-1,5-pentylene adipatediol having an average molecular weight of 2000, 100 parts by mass of polypropylene glycol having an average molecular weight of 2000, and 44.4 parts by mass of isophorone diisocyanate was charged and reacted at 100 to 105° C. for 6 hours while introducing nitrogen gas. After cooling to near room temperature, 521 parts by mass of ethyl acetate and 92 parts by mass of isopropyl alcohol were added, and then 15.6 parts by mass of isophoronediamine was added to extend the chain. Thereafter, 2.54 parts by mass of isophoronediamine, and 0.2 parts of diethylenetriamine. The reaction was stopped by adding 17 parts by mass to obtain a polyurethane resin varnish D (solid content: 30% by mass, viscosity: 250 mPa·s/25° C.).

Polyurethane resin varnish E production example (no primary amino groups at the ends, hydroxyl groups at both ends (ie two hydroxyl groups))
100 parts by mass of 3-methyl-1,5-pentylene adipatediol having an average molecular weight of 2000, 100 parts by mass of polypropylene glycol having an average molecular weight of 2000, and isophorone were placed in a four-necked flask equipped with a stirrer, a cooling pipe, and a nitrogen gas introduction pipe. 44.4 parts by mass of diisocyanate was charged and reacted at 100 to 105° C. for 6 hours while introducing nitrogen gas. After allowing to cool to near room temperature, 521 parts by mass of ethyl acetate and 92 parts by mass of isopropyl alcohol were added, 15.6 parts by mass of isophoronediamine was added to extend the chain, and 1.01 parts by mass of monoethanolamine was further added to react. After stopping, a polyurethane resin varnish E (solid content 30% by mass, viscosity 230 mPa·s/25° C.) was obtained.

(Production of printing ink composition for lamination)
35 parts by weight of pigment (titanium oxide), 30 parts by weight of polyurethane resin varnishes A to E, and 10 parts by weight of mixed solvent are kneaded using a paint conditioner, and the remaining mixed solvent A or B is added and mixed according to the formulation of Table 1. 100 parts by mass of each mixture was diluted with a curing agent (Mytec NY260A, manufactured by Mitsubishi Chemical Co., Ltd., Mitec is a registered trademark of Mitsubishi Chemical Co.) and a mixed solvent according to the composition shown in Table 1 at the time of printing, and the viscosity was separated. The printing ink compositions for laminating of Examples 1 to 7 and Comparative Examples 1 to 3 adjusted to 15 seconds by Zahn cup #3 were prepared.

<Performance evaluation>
The laminating printing ink compositions of Examples 1 to 5 and Comparative Examples 1 to 3 were engraved (Helio 175 line), and the laminating printing ink compositions of Examples 6 to 7 were engraved (Helio 200 line). ) Equipped with a gravure printing machine (manufactured by Toya Seisakusho Co., Ltd.) at a printing speed of 100 m/min on the treated surface of ONY#15 (manufactured by Toyobo Co., Ltd., N-1102, thickness 15 μm, hereinafter referred to as base film). Printed.

(Dry laminate)
An adhesive containing a polyester adhesive having a hydroxyl group and an isocyanate adhesive containing an isocyanate group in each of the printed materials of Examples 1 to 7 and Comparative Examples 1 to 3 (A-515/A manufactured by Mitsui Chemicals, Inc.) -50 ethyl acetate solution) was applied and a sealant film LLDPE#50 (manufactured by Toyobo Co., Ltd., L-4104) was laminated by a dry laminating machine to obtain a laminate.

(Extrusion lamination)
An adhesive (A-3210/A-3070 (manufactured by Mitsui Chemicals, Inc.)) is applied to each of the printed materials of Examples 1 to 7 and Comparative Examples 1 to 3, and molten polyethylene is laminated by an extrusion laminating machine to form a laminate. Got

(Color development)
The composition of the printing ink for laminating of Examples 1 to 7 and Comparative Examples 1 to 3 was printed on the above base film by a gravure printing machine using a printing plate of 175 lines to compare the color developability of each printed matter. The color development level of the composition for printing ink for laminating of Example 3 was used as a standard, and the level of color development was visually observed and evaluated according to the following evaluation criteria.
◯: clearer than the color developability of Comparative Example 3 x: not clearer than the color developability of Comparative Example 3

(Tearability)
After each laminate of Examples 1 to 7 and Comparative Examples 1 to 3 obtained by dry lamination and extrusion lamination was stored at 40° C. for 3 days, a cut was made with a cutter and the tearability was high when tearing by hand. evaluated.
◯: Tear without resistance Δ: Resistance is felt during tearing, or some sealant elongation occurs but somehow tears ×: Sealant elongation occurs or no tear occurs

Hardener: Isophorone diisocyanate (IPDI adduct) (Mitsubishi Chemical Co., Mitec NY260A)
Mixed solvent: ethyl acetate/propyl acetate/isopropyl alcohol=50/25/25 (mass ratio)

The laminates of the respective examples printed by using the printing ink composition for lamination of the present invention show good color developability using any printing plate of 175 lines and 200 lines, and dry laminate and Even if laminating was performed by any of the extrusion laminating methods, it showed good easy tearing property that it was tearable without resistance.
On the other hand, according to Comparative Examples 1 to 3 in which the ratio of the curing agent to the used polyurethane resin is less than the range in the present invention, although the color developability is good, the easy tearability is inferior and the elongation of the sealant is increased. It occurred a little, but it was just torn. Furthermore, according to Comparative Example 2 in which a polyurethane resin having a primary amino group at the terminal but not a hydroxyl group was used, a laminate having good color development but not tearing was obtained. Further, according to Comparative Example 3 in which a polyurethane resin having a hydroxyl group at the terminal but not having an amino group was used, the color developability was not good, and in addition, resistance was felt during tearing.

Claims (6)

A printing ink composition for laminating containing a pigment, a binder resin, a polyfunctional isocyanate compound as a curing agent, and an organic solvent, wherein the binder resin has a reactive group capable of reacting with an isocyanate group of the polyfunctional isocyanate compound. A printing ink composition for laminating, wherein the solid content ratio of the polyurethane resin and the curing agent is polyurethane resin:curing agent=1:0.35-0.9 (provided that styrene is used). The polyol component of the raw material of the polyurethane resin is a polyester diol obtained by reacting ethylene glycol and neopentyl glycol (molar ratio=1/1) with adipic acid, except when containing a maleic anhydride resin. In addition, the case where the curing agent has an isocyanate group and an alkoxysilyl group and the case where it is a blocked isocyanate is excluded). The polyurethane resin has at least one of a primary amino group, a secondary amino group, and a tertiary amino group at the terminal (1), and has a hydroxyl group, and/or (2) terminal. The printing ink composition for laminating according to claim 1, which is a polyurethane resin having at least one of a primary amino group, a secondary amino group and a tertiary amino group. The printing ink composition for laminating according to claim 1 or 2, wherein the polyfunctional isocyanate compound is a trifunctional or higher functional isocyanate compound. The printing ink composition for laminating according to claim 1, wherein the organic solvent is a mixed solvent of an ester organic solvent and an alcohol organic solvent. An easily tearable laminate in which a printing layer comprising the printing ink for lamination according to any one of claims 1 to 4, an adhesive layer having a hydroxyl group, and a sealant film are sequentially laminated on a base film. It is obtained by printing the printing ink for lamination according to any one of claims 1 to 4 on the base film, applying an adhesive having a hydroxyl group, and laminating a sealant film. The easily tearable laminated body according to 1.