JP2021134231A - Printing ink composition for laminate and laminate which can be torn easily - Google Patents

Abstract

To provide a printing ink composition for laminate capable of exhibiting preferable color development and ease of tearing, without using a large amount of a curing agent, and a laminate which can be torn easily which is formed by, after printing the printing ink for laminate to a substrate film, applying an adhesive agent, and laminating a sealant film to the substrate film.SOLUTION: There is provided a printing ink composition for laminate comprising a pigment, a binder resin, a polyfunctional isocyanate compound as a curing agent, and an organic solvent. The binder resin is a polyurethane resin which has a reactive group reacting an isocyanate group in the polyfunctional isocyanate compound, and in a polymer diol being a raw material of the polyurethane resin, a polyester diol is included by 70 mass% or greater, and a solid content ratio of the polyurethane resin and the curing agent is that: polyurethane resin: curative=1:0.10 to 0.90.SELECTED DRAWING: None

Description

The present invention relates to an easily tearable laminate obtained by printing the laminating printing ink on a laminating printing ink composition and a base 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. in consideration of functions such as design, economy, content protection, and transportability. In addition, many packaging materials are gravure-printed or flexographic-printed with the intention of giving them a design and message that appeals to consumers.
Then, in order to obtain the packaging material for the intended use, a front print printed on the surface of the base film of the packaging material, or an adhesive or an anchor agent is applied to the printed surface of the base film of the packaging material as necessary. Back printing is performed by laminating the film.
In back printing, color ink and white ink are sequentially printed on various films such as polyester, nylon, and aluminum foil, and then dry lamination using an adhesive or anchor coating agent is applied on the printing layer of the white ink. A polyethylene film, a polypropylene film, or the like is laminated for the purpose of heat sealing by the extrusion laminating process used (see, for example, Patent Document 1).

After that, the laminate is used as a laminate bag for foods such as sweets, soups, and miso soup. These laminated bags are opened by human hands to remove the contents. Here, if the tearability is poor, it is necessary to apply excessive force at the time of opening, and the product is cut in an unintended direction, resulting in a problem that the contents are spilled. Therefore, good tearability is required.
In particular, the portion 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 laminate adhesive layer (see, for example, Patent Document 2), but the ink portion and the ink are not printed. When the character portions are mixed, if the adhesive layer is made hard enough to be torn by the ink portion, the non-character portion becomes too hard, and conversely, if the adhesive layer is adjusted to the non-character portion, the ink portion has a problem of inferior tearability.

In order to solve this, 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 hydroxyl group as a functional group in the molecule. It has been proposed to form a layer formed of a composition consisting of a compound (a1) having only two or more and a curing agent that reacts with its hydroxyl group (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 as polyurethane resin: polyfunctional isocyanate curing agent = 1: 0.25, so that the tearability is slightly improved. However, it still has insufficient problems such as feeling resistance when tearing.
Further, the color-developing property of the ink layer using such a compound is not sufficiently good.

In Patent Document 4, a large amount of a curing agent is used in the two-component ink to improve the tearability, but since the large amount of the curing agent has a large effect on the cost, there is room for improvement.
In Patent Document 5, it is possible to reduce the amount of the curing agent as compared with Patent Document 4, but further reduction of the curing agent is required while maintaining tearability.

Japanese Unexamined Patent Publication No. 5-97959 Japanese Unexamined Patent Publication No. 2008-274061 Japanese Unexamined Patent Publication No. 2012-125978 Japanese Unexamined Patent Publication No. 2017-25143 Japanese Patent No. 6545559

An object of the present invention is a printing ink composition for laminating that can exhibit good color development and easy tearing property without using a large amount of a curing agent, and an adhesive after printing the printing ink for laminating on a base film. To provide an easily tearable laminate formed by laminating a sealant film.

As a result of diligent studies to solve the above problems, the present inventors have invented the following printing ink composition for lamination and a laminate.
The present invention
(1) A printing ink composition for lamination containing a pigment, a binder resin, a polyfunctional isocyanate compound as a curing agent, and an organic solvent, wherein the binder resin is a reactive group capable of reacting with the isocyanate group of the polyfunctional isocyanate compound. The polyester diol is 70% by mass or more in the polymer diol which is the raw material of the polyurethane resin, and the solid content ratio of the polyurethane resin and the curing agent is polyurethane resin: curing agent = 1. : A printing ink composition for laminating, which is 0.10 to 0.90.
(2) The printing ink composition for lamination according to (1), wherein the polyurethane resin is the following (1) or (2), or a mixture of the following (1) and (2).
(1) Polyurethane resin having one or more of a primary amino group, a secondary amino group and a tertiary amino group at the terminal and having a hydroxyl group (2) A primary amino group and a primary amino group at the terminal Polyurethane resin having at least one of a secondary amino group and a tertiary amino group (3) The above (1) or (2), wherein the polyfunctional isocyanate compound is a trifunctional or higher functional isocyanate compound. ). The printing ink composition for lamination.
(4) The above-mentioned (1) to (3), wherein the pigment contains rutile-type titanium oxide having an oil absorption amount of 20 to 35 g / 100 g, which is treated with silica and alumina. Printing ink composition for laminating.
(5) The printing ink composition for lamination according to (4) above, wherein the pigment contains rutile-type titanium oxide having an oil absorption of 25 to 35 g / 100 g, which is treated with silica and alumina.
(6) The printing ink composition for lamination according to any one of (1) to (5) above, wherein the organic solvent is a mixed solvent of an ester-based organic solvent and an alcohol-based organic solvent.
(7) Easy-to-tear laminating in which a printing layer made of the printing ink for laminating according to any one of (1) to (6) above, an adhesive layer having a hydroxyl group, and a sealant film are laminated in this order on a base film. body.
(8) After printing the laminating printing ink according to any one of (1) to (6) above on the base film, an adhesive containing a resin having a hydroxyl group is applied, and the sealant film is laminated. The easily tearable laminate according to (7) above, which is obtained.

The printing ink composition for lamination of the present invention uses the above polyurethane resin as a binder resin, a polyfunctional isocyanate compound as a curing agent, and the solid content ratio of the polyurethane resin and the curing agent is polyurethane resin: curing agent = 1: It is a composition used in the range of 0.10 to 0.90. The polyurethane resin has a reactive group that can react with the isocyanate group of the polyfunctional isocyanate compound. Therefore, the curing agent in the printing ink composition for lamination reacts with the polyurethane resin in the ink composition and the hydroxyl group of the adhesive layer to increase the bonding force between the printing layer and the adhesive layer, and the ink It is considered that the layer becomes hard and the tearability becomes good.
In particular, as the polyurethane resin, (1) a polyurethane resin having one or more 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 one or more of a primary amino group, a secondary amino group and a tertiary amino group at the terminal, and a polyfunctional isocyanate compound as a curing agent, a polyurethane resin, and a solid content ratio of the curing agent. However, when it is used in the range of polyurethane resin: curing agent = 1: 0.10 to 0.90, the polyurethane resin viscosity can be adjusted to an appropriate viscosity range for printing ink, and the pigment dispersibility is also good. The resin content in the printing ink composition for lamination can be increased.
Further, since the polyurethane resin has a hydroxyl group, the curing agent in the printing ink composition for lamination reacts with the hydroxyl group of the adhesive layer to increase the bonding force between the printing layer and the adhesive layer. It is considered that the ink layer becomes hard and the tearability becomes good. Further, it is considered that the color-developing property is also good because the pigment dispersibility is good.

Hereinafter, the printing ink composition for lamination 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.
The content of the pigment in the printing ink composition for lamination of the present invention is preferably in the range of 5 to 60% by mass in the ink composition.
When the content of the pigment in the printing ink composition for lamination is less than the above range, the coloring power of the ink composition is lowered, and when it is more than the above range, the viscosity of the ink composition is increased and the printed matter becomes dirty. It will be easier.
The pigment preferably contains rutile-type titanium oxide having an oil absorption of 20 to 35 g / 100 g treated with silica and alumina, and has an oil absorption of 25 to 35 g / 100 g treated with silica and alumina. It is more preferable to contain rutile-type titanium oxide.
If the oil absorption amount is less than 20 g / 100 g, the tearability may be lowered, and if it exceeds 35 g / 100 g, the pigment dispersibility may be deteriorated.

<Binder resin>
As the binder resin, a polyurethane resin having a reactive group capable of reacting with the isocyanate group of the polyfunctional isocyanate compound which is the 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 one or more of a primary amino group, a secondary amino group and a tertiary amino group and / or a hydroxyl group at the terminal. Polyurethane resin having can be used. In particular, a polyurethane resin having at least one of a primary amino group, a secondary amino group and a tertiary amino group at the (1) terminal and having a hydroxyl group and / or a first at the (2) terminal. A polyurethane resin having at least one of a secondary amino group, a secondary amino group and a tertiary amino group is preferable.
In such a polyurethane resin, a urethane prepolymer is synthesized by reacting a polyfunctional diisocyanate compound with a polymer diol compound, and with respect to the obtained urethane prepolymer, (1) both ends have a primary amino group and a primary amino group. By reacting an amine compound containing a polyamine compound which is one or more of a secondary amino group and a tertiary amino group, and an amine compound having a hydroxyl group, or (2) both ends are primary aminos. It is obtained by reacting an amine compound containing a polyamine compound which is one or more of a group, a secondary amino group and a tertiary amino group.
At this time, the urethane prepolymer and (1) an amine compound containing a polyamine compound having one or more of a primary amino group, a secondary amino group and a tertiary amino group at both ends, and a hydroxyl group are used. Method of reacting with an amine compound having, (2) Reacting an amine compound containing a polyamine compound having one or more of a primary amino group, a secondary amino group and a tertiary amino group at both ends. The methods include (A) chain extension of the urethane prepolymer with a chain extender and then termination of the reaction with a reaction terminator, and (B) chain extension of the urethane prepolymer with a chain extender and a reaction terminator. Examples thereof include a method in which the reaction is stopped at the same time.

(Polyfunctional diisocyanate compound)
Examples of the polyfunctional diisocyanate compound that can be used to obtain a binder resin include aromatic diisocyanate compounds such as tolylene diisocyanate, alicyclic diisocyanate compounds such as 1,4-cyclohexane diisocyanate and isophorone diisocyanate, and hexamethylene diisocyanate. An aliphatic diisocyanate compound and an aromatic aliphatic diisocyanate compound such as α, α, α', α'-tetramethylxylylene diisocyanate can be used alone or in combination of two or more. Of these, alicyclic diisocyanate compounds, aliphatic diisocyanate compounds and aromatic aliphatic diisocyanate compounds are more preferable. Further, trifunctional or higher functional isocyanate compounds can also be used. Further, it is more preferable that the isocyanate component is a plant-derived bioisocyanate.

(Polymer diol compound)
Examples of the polymer diol compound that can be used to obtain a binder resin include polyalkylene glycols such as polyethylene glycol and polypropylene glycol, and polyether diol compounds such as ethylene oxide of bisphenol A and alkylene oxide adduct such as propylene oxide. One or more dibasic acids such as adipic acid, sebacic acid, phthalic anhydride, ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol Various high molecular weight diol compounds such as polyester diols obtained by condensing one or two or more kinds of glycols such as, and polyester diol compounds such as polycaprolactone diols can be mixed and used. ..
Among the above polymer diols, polyester diol is 70% by mass or more.
A biopolyol component can be adopted as the polymer diol compound. Of these, a biopolyester polyol obtained by reacting a short-chain diol component having 2 to 4 carbon atoms with a carboxylic acid component is preferable. As for the biopolyol component, it is more preferable that at least one of the short-chain diol component and the carboxylic acid component is derived from a plant, and it is further preferable that both are derived from a plant.
The plant-derived short-chain diol component having 2 to 4 carbon atoms is not particularly limited. As an example, the short chain diol component may be 1,3-propanediol, 1,4-butanediol, ethylene glycol or the like obtained from a plant raw material by the following method. These may be used together. 1,3-Propanediol can be produced from glycerol via 3-hydroxypropyl aldehyde (HPA) by a fermentation method in which glucose is obtained by decomposing a plant resource (for example, corn). The 1,3-propanediol compound produced by a bio-method such as the above fermentation method produces useful by-products such as lactic acid, which is superior in safety to the 1,3-propanediol compound produced by the EO production method. Moreover, the manufacturing cost can be kept low. 1,4-Butanediol can be produced by obtaining succinic acid obtained by producing glycol from plant resources and fermenting it, and hydrogenating it.
Further, ethylene glycol can be produced from bioethanol obtained by a conventional method via ethylene.

The plant-derived carboxylic acid component is not particularly limited. For example, the carboxylic acid component is sebacic acid, succinic acid, lactic acid, glutaric acid, azelaic acid, dimer acid and the like. These may be used together. Among these, the carboxylic acid component preferably contains at least one selected from the group consisting of sebacic acid, succinic acid and dimer acid.

Further, in addition to the above polymer diol compound, alkanediol such as 1,4-pentanediol, 2,5-hexanediol, 3-methyl-1,5-pentanediol, ethylene glycol, propylene glycol, 1,4- One or two or more low molecular weight diol compounds such as butanediol and 1,3-butanediol can be mixed and used in combination.
In the mixture system of the ester solvent and the alcohol solvent, the solubility of the obtained polyurethane resin tends to be higher when the polyether diol compound is used as the polymer diol compound, and it is widely used according to the required performance. It is preferable in that it enables the design of ink.
The ratio of the organic diisocyanate compound to the polymer diol compound is such that the equivalent ratio of isocyanate groups: hydroxyl groups (isocyanate index) is usually 1.2: 1 to 3.0: 1, more preferably 1.3:. It is in the range of 1 to 2.0: 1. When the above isocyanate index is smaller than 1.2, it tends to be a flexible polyurethane resin, and when the blocking resistance and the like are low when printing ink, it may be preferable to use it in combination with another hard resin. be.

(Chain extender)
As the chain extender that can be used to obtain the binder resin, known chain extenders used in polyurethane resins as ink binders can be used, and ethylenediamine, propylenediamine, tetramethylenediamine, and hexamethylene can be used. Aliper diamines such as diamines, isophorone diamines, alicyclic diamines such as 4,4'-dicyclohexylmethanediamine, polyamines such as diethylenetriamine and triethylenetetratriamine, aromatic diamines such as toluylenediamine, and xylenediamine. Aromatic aliphatic diamines such as N- (2-hydroxyethyl) ethylenediamine, N- (2-hydroxyethyl) propylene diamine, diamines having a hydroxyl group such as N, N'-di (2-hydroxyethyl) ethylenediamine, etc. Examples thereof include diol compounds such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, diamine glycol, and triethylene glycol.

(Reaction terminator)
Examples of the reaction terminator that can be used to obtain a binder resin include aliphatic diamines such as trimethylenediamine and hexamethylenediamine, isophoronediamines, and alicyclic diamines such as 4,4′-dicyclohexylmethanediamine. Polyamines such as diethylenetriamine and triethylenetetratriamine, aromatic diamines such as toluylenediamine, aromatic aliphatic diamines such as xylenediamine, N- (2-hydroxyethyl) ethylenediamine, N- (2-hydroxyethyl) propylene Polyamine compounds having primary amino groups at both ends, such as diamines having a hydroxyl group such as diamine, N, N'-di (2-hydroxyethyl) ethylenediamine, and monoalkylamines such as n-propylamine and n-butylamine. , Dialkylamines such as di-n-butylamine, alkanolamines such as monoethanolamine and diethanolamine, monoalcohols such as ethanol, and the like can be exemplified.
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 such polyamines 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, and 4,4'-. Alicyclic diamines such as dicyclohexylmethanediamine, polyamines such as diethylenetriamine and triethylenetetratriamine, aromatic diamines such as toluylene diamine, aromatic aliphatic diamines such as xylene diamine, N- (2-hydroxyethyl) Diamines having a hydroxyl group such as ethylenediamine and N- (2-hydroxyethyl) propylenediamine, among which 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. Preferably, it is preferable to use a compound having a hydroxyl group in 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. can.
Examples of the reaction terminator include diamines having a hydroxyl group such as N- (2-hydroxyethyl) ethylenediamine, N- (2-hydroxyethyl) propylenediamine, and N, N'-di (2-hydroxyethyl) ethylenediamine, and monoethanol. Examples thereof include alkanolamines having a hydroxyl group such as amine and diethanolamine.

In the present invention, a polyurethane resin can be obtained by using the above-mentioned materials and adopting a known method for producing a polyurethane resin. Further, if the molecular weight, chemical structure, and equivalent ratio of each component are different, the hardness of the obtained polyurethane resin is also different. Therefore, the printability and the laminate suitability can be adjusted by appropriately selecting and combining these components. It is possible.
The content of the binder resin is preferably 5 to 15% by mass in terms of solid content in the printing ink composition for laminating at the time of printing. If the content of the binder resin is out of the above range, the tearability tends to decrease.
The polyurethane resin in the printing ink composition for lamination of the present invention preferably has a mass average molecular weight of 1000 to 70000, more preferably 20000 to 40,000.
Further, as other binder resins, a cellulose resin, an acrylic resin, a vinyl chloride vinyl acetate copolymer, a polyamide resin, an adhesive resin and the like can be additionally added. Among these, a vinyl chloride vinyl acetate copolymer is preferable, and a vinyl chloride vinyl acetate copolymer having a hydroxyl group is particularly preferable from the viewpoint of reaction with a curing agent.

<Hardener>
As the curing agent, a polyfunctional polyisocyanate compound can be used. Specifically, biuret, isocyanurate, adduct, a bifunctional polyfunctional isocyanate compound, and isophorone diisocyanate can be used, and 24A-100, 22A-75, TPA-100, TSA-100, TSS-100, and TAE-100 can be used. , TKA-100, P301-75E, E402-808, E405-70B, AE700-100, D101, D201, A201H (manufactured by Asahi Kasei Corporation), Mitec Y260A (manufactured by Mitsubishi Chemical Co., Ltd.), Coronate CORONATE HX, Coronate CORONATE Examples thereof include HL, coronate isocyanate L (manufactured by Tosoh Corporation), and death module N75MPA / X (manufactured by Bayer). Of these, isophorone diisocyanate or its adduct is preferable. Further, trifunctional or higher functional isocyanate compounds can also be used.
Further, it is more preferable that the isocyanate component is a plant-derived bioisocyanate.
The amount of this curing agent used is such that the mass ratio of the content of the polyurethane resin and the curing agent is in the range of polyurethane resin: curing agent = 1: 0.10 to 0.90 from the viewpoint of tearability. , Polyurethane resin: curing agent = 1: 0.13 to 0.40, more preferably polyurethane resin: curing agent = 1: 0.15 to 0.35.

<Organic solvent>
Examples of the organic solvent used in the printing ink composition for lamination include toluene, ketone-based organic solvents (for example, acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.), and ester-based organic solvents (for example, methyl acetate, ethyl acetate, n-acetate). Alcoholic organic solvents (eg, methanol, ethanol, n-propanol, isopropanol, butanol, etc.) and hydrocarbon solvents (toluene, methylcyclohexane, etc.) can be used.
In consideration of recent environmental problems, printability and dryness of inks, ester-based organic solvents and alcohol-based organic solvents are used as organic solvents for laminating printing ink compositions during printing. The mixed organic solvent is set in the range of ester-based organic solvent / alcohol-based organic solvent = 50/50 to 95/5, preferably in the range of ester-based organic solvent / alcohol-based organic solvent = 60/40 to 85/15. It is preferable to use it.
Further, from the viewpoint of ink printability, it is preferable that propyl acetate is contained in the printing ink composition for lamination at the time of printing in an amount of 5% by mass or more, preferably 15% by mass or more.

<Additives>
Various additives such as a tackifier, a cross-linking agent, a lubricant, a blocking agent, an antistatic agent, and a surfactant can be further added to the organic solvent-based gravure printing composition.

<Manufacturing Method of Printing Ink Composition for Laminating of the Present Invention>
The printing ink composition for laminating of the present invention is produced by using various dispersion / kneading devices that are generally used conventionally for various materials other than the above-mentioned curing agent, and the content of each solid content material. After adjusting the viscosity to 10 to 1000 mPa · s by adjusting the combination of polyurethane resin and organic solvent, a curing agent is added at the time of printing from the viewpoint of stability over time, and printing is performed at the atmospheric temperature at the time of printing. To make the number of seconds appropriate according to the conditions, specifically, add an organic solvent and stir until the outflow time of Zahn Cup No. 3 is 12 to 23 seconds, preferably about 14 to 16 seconds for high-speed printing. Can be obtained by printing.

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

(Base film)
The base film of the easily tearable laminate of the present invention is not particularly limited, and is not particularly limited, a polyolefin film such as polyethylene and polypropylene, a polyester film such as polyethylene terephthalate, polylactic acid and polycaprolactone, and various plastic films for printing such as nylon and vinylon. Can be used.
Further, a biomass-based film made of a biomass-based resin can be used.

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

(glue)
Conventionally, an adhesive containing a resin having a hydroxyl group, which has been used in extrusion laminating processing and dry laminating processing, can be used. For example, a polyester adhesive having a hydroxyl group, an adhesive containing an isocyanate group containing an isocyanate group, and the like can be exemplified.
Specifically, the adhesives (anchor coating agents) used in the extrusion laminating process include A-3210 / A-3070, A-3210 / A3072, and A-3210 / A-3075 (manufactured by Mitsui Chemicals, Inc.). ), Secadyne 2710A / Secadyne 2810C (T), Secadyne 2730A / Secadyne 2730B, Secadyne 2710A / Secadine 2710C (manufactured by Dainichiseika Kogyo Co., Ltd.), LX-500, LX-901, LX747A, etc. Adhesives used include Dick Dry LX-401A, 75A, 719, 703VL, 500, 510, etc. (manufactured by DIC Graphics, Dic 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, Inc.), RU-77, 771, 3600, 3900, etc. (manufactured by Rock Paint) and the like.
In addition, a biomass-based adhesive made of a biomass-based material can also be used.

(Sealant film)
As the sealant film, conventionally used resins such as low density polyethylene, LLDPE, ethylene-vinyl acetate copolymer, polypropylene and the like can be used as the molten resin used when the laminating means by the dry laminating process is adopted.
Further, as the plastic film used in the extrusion laminating process by laminating the molded film, a conventionally used film such as a non-stretched plastic film (for example, a non-stretched polyethylene film, a non-stretched polypropylene film, etc.) can be used. ..

<Easy-tearable laminate and easy-to-tear laminate>
The easily tearable laminate and the easily tearable laminate 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, using the printing ink composition for laminating of the present invention.
A laminating process is performed in which a heat-sealing polymer called a sealant is laminated on the obtained printed matter. Two main methods are used for this laminating process.
The first is that printing is performed with a printing ink composition for laminating, and after or before the printing portion is cured with a curing agent, an adhesive (also referred to as an anchor coating agent) is applied to the surface of the obtained printing layer. ) Is applied, and then a heat-sealing polymer is used as a molten resin, and this is laminated. The extrusion laminating method is a known extrusion method in which an adhesive (for example, a polyester adhesive having a hydroxyl group and an adhesive containing an isocyanate group containing an isocyanate group) is applied to the surface of the printing layer, and then the surface is coated with an adhesive. The molten resin is laminated by a laminating machine. Further, the molten resin can be used as an intermediate layer, and another material can be laminated to form a sandwich. It should be noted that it is preferable to use an isocyanate-based anchor coating agent rather than using an imine-based anchor coating agent as the adhesive in that the adhesive strength is excellent.
The second is that printing is performed with a printing ink composition for laminating, and after or before the printing portion is cured with a curing agent, an adhesive (for example, a polyester-based material having a hydroxyl group) is applied to the surface of the printing layer. This is a dry laminating process in which a non-stretched plastic film is laminated after coating an adhesive and an adhesive containing an isocyanate-based adhesive containing an isocyanate group). In particular, it is also possible to laminate a metal foil used for retort pouching using a film composed of a plurality of layers sandwiched in advance.
The easily tearable laminates obtained by these methods are finally sealed with a heat sealer or the like between the sealant surfaces to form an easily tearable laminate bag.
As a matter common to these two methods, when printing is performed with the printing ink composition for laminating, the printing portion is cured with a curing agent, and then the adhesive is applied, the printing ink for laminating is applied. The composition and the adhesive may be cured by different functional groups, that is, by different curing mechanisms, or a curing agent on which the same functional group acts 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 laminating and an adhesive is applied before the printing portion is cured with a curing agent, the printing ink composition for laminating and the adhesive are the same as each other. Hardeners on which functional groups act can also be used.

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 "% by mass" and "part" means "part by mass".

(Manufacturing of polyurethane resin varnish)
Polyurethane resin varnish A production example (100% by mass of polyester diol in polymer diol, primary amino group at the end, hydroxyl group at the end)
In a four-necked flask equipped with a stirrer, a cooling tube and a nitrogen gas introduction tube, 400 parts by mass of 3-methyl-1,5-pentylene adipatediol having an average molecular weight of 2000, 33.3 parts by mass of isophorone diisocyanate, and tetra. 0.04 parts by mass of butyl titanate was charged and reacted at 80 to 90 ° C. for 6 hours while introducing nitrogen gas. Allow to cool to near room temperature, add 824 parts by mass of propyl acetate and 206 parts by mass of isopropyl alcohol, add 7.6 parts by mass of isophorone diamine to extend the chain, and add 0.37 parts by mass of monoethanolamine to react. Then, 0.41 part by mass of diaminetriamine was added and the reaction was stopped to obtain a polyurethane resin varnish A having a solid content of 30% by mass.

Polyurethane resin varnish B production example (100% by mass of polyester diol in polymer diol, primary amino group at the end, hydroxyl group in the molecule and at the end)
In a four-necked flask equipped with a stirrer, a cooling tube and a nitrogen gas introduction tube, 400 parts by mass of 3-methyl-1,5-pentylene adipatediol having an average molecular weight of 2000, 33.3 parts by mass of isophorone diisocyanate, and tetra. 0.04 parts by mass of butyl titanate was charged and reacted at 80 to 90 ° C. for 6 hours while introducing nitrogen gas. After allowing to cool to near room temperature and adding 822 parts by mass of propyl acetate and 205 parts by mass of isopropyl alcohol, a mixture of 3.8 parts by mass of isophoronediamine and 2.3 parts by mass of aminoethylethanolamine was added to extend the chain, and further. 0.37 parts by mass of monoethanolamine was added for reaction, and then 0.41 parts by mass of diethylenetriamine was added to terminate the reaction to obtain a polyurethane resin varnish B having a solid content of 30% by mass.

Polyurethane resin varnish C production example (polyester diol / polyether diol in polymer diol = 80/20 (mass ratio), primary amino group at the end, hydroxyl group at the end)
In the production example of polyurethane resin varnish A, 400 parts by mass of 3-methyl-1,5-pentylene adipatediol having an average molecular weight of 2000, 320 parts by mass of 3-methyl-1,5-pentylene adipatediol having an average molecular weight of 2000, and 320 parts by mass. By changing to a mixture of 80 parts by mass of polypropylene glycol having an average molecular weight of 2000, a polyurethane resin varnish C having a solid content of 30% by mass was obtained.

Polyurethane resin varnish D production example (100% polyester diol in polymer diol, primary amino group at the end, no hydroxyl group)
In the production example of polyurethane resin varnish A, monoethanolamine was changed to dibutylamine to obtain polyurethane resin varnish D having a solid content of 30% by mass.

Polyurethane resin varnish E production example (100% polyester diol in polymer diol, no primary amino group at the end, hydroxyl groups (that is, two hydroxyl groups) at both ends)
In the production example of polyurethane resin varnish A, diethylenetriamine was changed to monoethanolamine to obtain polyurethane resin varnish E having a solid content of 30% by mass.

Polyurethane resin varnish F production example (polyester diol / polyether diol = 50/50 (mass ratio) in polymer diol, primary amino group at the end, hydroxyl group at the end)
In the production example of polyurethane resin varnish A, 400 parts by mass of 3-methyl-1,5-pentylene adipatediol having an average molecular weight of 2000, 200 parts by mass of 3-methyl-1,5-pentylene adipatediol having an average molecular weight of 2000, and 200 parts by mass. A polyurethane resin varnish F having a solid content of 30% by mass was obtained by changing to a mixture of 200 parts by mass of polypropylene glycol having an average molecular weight of 2000.

Polyurethane resin varnish G production example (polyurethane resin varnish A with reduced molecular weight: for Helio 200 wire)
In the production example of polyurethane resin varnish A, the solid content is 30 by changing the amount of isophorone diamine to 6.8 parts by mass, the amount of monoethanolamine to 0.73 parts by mass, and the amount of diethylenetriamine to 0.82 parts by mass. A mass% polyurethane resin varnish G was obtained.

(Pigment)
Titanium oxide A (rutile type titanium oxide treated with silica and alumina, oil absorption 29g / 100g)
Titanium oxide B (rutile type titanium oxide treated only with alumina, oil absorption 29g / 100g)

(Salt vinegar vinyl acetate varnish)
20 parts by mass of vinyl chloride vinyl acetate copolymer having a hydroxyl group (trade name: solvent TA3, manufactured by Nissin Chemical Industry Co., Ltd.), mixed organic consisting of 40 parts by mass of methyl ethyl ketone, 20 parts by mass of ethyl acetate, and 20 parts by mass of propyl acetate. It was dissolved in a solvent to obtain a vinyl acetate resin varnish A having a solid content of 20%.

(Manufacturing of printing ink composition for lamination)
35 parts by mass of pigments A to B, 30 parts by mass of polyurethane resin varnishes A to G, and 10 parts by mass of mixed solvent were kneaded using a paint conditioner, and the residue of mixed solvent 1 was added and mixed according to the formulation shown in Table 1. Dilute 100 parts by mass with a curing agent (trade name "Mytec NY260A", manufactured by Mitsubishi Chemical Co., Ltd.) and a mixed solvent 2 according to the formulation shown in Table 1 at the time of printing, and adjust the viscosity to Zahn Cup # 3 manufactured by Rigosha Co., Ltd. The printing ink compositions for lamination of Examples 1 to 10 and Comparative Examples 1 to 4 were prepared in 15 seconds.

<Performance evaluation>
The printing ink composition for lamination of Examples 1 to 8 and Comparative Examples 1 to 4 is an engraving plate (helio 175 lines), and the printing ink composition for lamination of Examples 9 to 10 is an engraving plate (helio 200 lines). A gravure printing machine (manufactured by Higashiya Seisakusho Co., Ltd.) equipped with I printed it.

(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 matter of Examples 1 to 10 and Comparative Examples 1 to 4 (manufactured by Mitsui Chemicals Co., Ltd., A-515 /). A-50 ethyl acetate solution) was applied, and LLDPE # 50 (manufactured by Toyo Boseki Co., Ltd., L-4104), which is a sealant film, was laminated with a dry laminating machine to obtain a laminated body.

(Extruded laminate)
An adhesive (A-3210 / A-3070 (manufactured by Mitsui Chemicals, Inc.)) is applied to each of the printed matter of Examples 1 to 10 and Comparative Examples 1 to 4, and molten polyethylene is laminated by an extrusion laminating machine to form a laminate. Got

(Color development)
The color-developing properties of each printed matter printed on the base film with the composition for laminating printing inks of Examples 1 to 10 and Comparative Examples 1 to 4 by a gravure printing machine using a 175-line printing plate are compared. The level of color development was visually observed and evaluated according to the following evaluation criteria, using the color development of the composition for printing ink for lamination of Example 3 as a standard.
◯: Those clearly recognized as clearer than the color-developing property of Comparative Example 3 ×: Those not recognized as clearer than the color-developing property of Comparative Example 3

(Tearability)
After each of the laminates of Examples 1 to 10 and Comparative Examples 1 to 4 obtained by dry laminating and extrusion laminating was allowed to elapse at 40 ° C. for 3 days, a cut was made with a cutter, and the tearability when torn by hand was determined. evaluated.
○: Tear without resistance ○ △: Slight resistance is felt when tearing, but tears without problems △: Resistance is felt when tearing, or some sealant stretches but somehow tears ×: Sealant stretch occurs or not at all Do not tear

Hardener: Isophorone diisocyanate (IPDI Adduct) (manufactured by Mitsubishi Chemical Corporation, Mitec NY260A)
Mixed Solvents 1 and 2: Ethyl Acetate / Propyl Acetate / Isopropyl Alcohol = 50/25/25 (Mass Ratio)

The laminate of each example printed using the printing ink composition for lamination of the present invention exhibits good color development regardless of whether a printing plate of 175 lines or 200 lines is used, and is a dry laminate and a dry laminate. Regardless of which method of extrusion lamination was used for laminating, it showed good tearability that it could be torn without resistance.
On the other hand, according to Comparative Examples 1 and 2 in which the ratio of the curing agent to the polyurethane resin used was smaller than the range in the present invention, although the color developing property was good, the tearability was inferior and the elongation of the sealant was slightly increased. It did occur, but it managed to tear. According to Comparative Example 3 in which a polyurethane resin having a hydroxyl group at the terminal but not an amino group was used, the color-developing property was not good, and in addition, resistance was felt at the time of tearing. According to Comparative Example 4 in which the polyester diol was 50% by mass in the polymer diol which is the raw material of the polyurethane resin, the tearability was inferior.

Claims (8)

A printing ink composition for lamination containing a pigment, a binder resin, a polyfunctional isocyanate compound as a curing agent, and an organic solvent.
The binder resin is a polyurethane resin having a reactive group capable of reacting with the isocyanate group of the polyfunctional isocyanate compound, and the polyester diol is 70% by mass or more in the polymer diol which is the raw material of the polyurethane resin.
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: 0.10 to 0.90. The printing ink composition for lamination according to claim 1, wherein the polyurethane resin is the following (1) or (2), or a mixture of the following (1) and (2).
(1) Polyurethane resin having one or more of a primary amino group, a secondary amino group and a tertiary amino group at the terminal and having a hydroxyl group (2) A primary amino group and a primary amino group at the terminal Polyurethane resin having at least one of a secondary amino group and a tertiary amino group The printing ink composition for lamination according to claim 1 or 2, wherein the polyfunctional isocyanate compound is a trifunctional or higher functional isocyanate compound. The printing ink composition for lamination according to any one of claims 1 to 3, wherein the pigment contains rutile-type titanium oxide having an oil absorption of 20 to 35 g / 100 g, which is treated with silica and alumina. .. The printing ink composition for lamination according to claim 4, wherein the pigment contains rutile-type titanium oxide having an oil absorption of 25 to 35 g / 100 g, which is treated with silica and alumina. The printing ink composition for lamination according to any one of claims 1 to 5, wherein the organic solvent is a mixed solvent of an ester-based organic solvent and an alcohol-based organic solvent. An easily tearable laminate in which a printing layer made of the printing ink for lamination according to any one of claims 1 to 6, an adhesive layer having a hydroxyl group, and a sealant film are laminated in this order on a base film. It is characterized in that it is obtained by printing the printing ink for laminating according to any one of claims 1 to 6 on the base film, applying an adhesive containing a resin having a hydroxyl group, and laminating a sealant film. The easily tearable laminate according to claim 7.