JP3386249B2 - Aqueous printing ink composition for plastic film and laminating method using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a water-based printing ink composition for a plastic film and a laminating method using the same, more specifically, good storage stability, strong adhesion to a plastic film, and high adhesion. The present invention relates to a water-based printing ink composition for plastic films, which has water resistance, gloss, and good laminate strength and boil retort suitability.

[0002]

2. Description of the Related Art Inks that have hitherto been used for printing on plastic films include basic properties of ink such as pigment dispersibility, adhesion to film, water resistance, drying property and printability, as well as lamination and boiling.・ Most of them were of solvent type because of their excellent post-processing suitability such as retort treatment.

However, recently, from many viewpoints such as environmental problems, resource saving, occupational hygiene and disaster prevention and safety, there is a demand for water-based printing inks in which the use of organic solvents is suppressed as much as possible, regardless of the fields of use of the inks. It's getting stronger. In particular, among them, printing inks for plastic films are often used for food packaging applications, so that the residual solvent of the inks poses a serious problem and the demand for water-based printing is particularly strong.

Therefore, as a water-based printing ink used in this field, one using a water-soluble acrylic resin as a binder has been developed. This is because the acrylic resin can be made water-based relatively easily, pigment dispersibility, printing This is because it has excellent suitability.

Further, a printing ink in which the binder resin is composed of only a water-soluble resin has insufficient water resistance and drying property, and therefore, at present, although the printability is somewhat deteriorated, water excellent in these properties is used. Inks that use a dispersible resin together are used.

However, the most disadvantageous point of the conventional water-based printing ink for plastic films as compared with that of the solvent type is that the ink is repelled on the film and it is difficult to obtain an ink film having good adhesion. In addition, it is also not possible to perform boil retort treatment in hot water (poor suitability for boil retort).

Therefore, various crosslinking systems have been proposed for the purpose of imparting adhesion of the ink film to the film, imparting boil / retort suitability, and improving the water resistance. For example, as an aqueous crosslinking system for a carboxyl group-containing resin, an aziridine crosslinking agent (for example,
JP-A-6-1939), epoxy-based cross-linking agent (for example, JP-A-5-171087), oxazoline-based cross-linking agent (for example, JP-A-5-271598), carbodiimide-based cross-linking agent (for example, JP-A-5-179598). 5-28722
No. 9), a metal chelate compound (JP-A-4-2250).
No. 81) has been proposed.

In all of these systems, the effect of improving the performance such as adhesion and water resistance is recognized, but the viscosity stability and printability of the ink over time are significantly reduced, and the system is not put into practical use. Not in.

Further, an aqueous crosslinking system comprising a water-dispersible resin obtained by emulsion polymerization of a carbonyl group-containing monomer and the like in the presence of a usual surfactant and a hydrazine-based crosslinking agent is disclosed in, for example, JP-A-4-249587. Has been proposed by. However, in these cross-linking systems, when the carbonyl group concentration in the system becomes high, the viscosity stability with time also decreases, so that it is unavoidable to use a water-dispersible resin having a low carbonyl group content concentration.

As a result, in order to obtain the original effect of the crosslinking system, it is necessary to add a large amount of the water-dispersible resin emulsion, and when it is applied to a printing ink, the printability becomes poor and a good printed matter cannot be obtained. There's a problem.

[0011]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is, in spite of being a water-based printing ink, basic properties such as pigment dispersibility, adhesion to a plastic film, water resistance, drying property and printability, and lamination processing. It is intended to provide a water-based printing ink composition for plastic films, which is also excellent in post-processability such as boil / retort treatment.

Further, an object of the present invention is to provide a laminating method using the above water-based printing ink composition for plastic films.

[0013]

That is, the present invention provides a coloring agent, an aqueous resin emulsion, and at least 2 in a molecule.
The present invention relates to a water-based printing ink composition for plastic films, which comprises a hydrazine-based crosslinking agent having three or more hydrazine residues as an essential component and satisfies the following conditions I and II.

Condition I The aqueous resin emulsion comprises a. 5 to 20 % by weight of carboxylic acid and / or acid anhydride having a radical-polymerizable double bond b. 1 to 4 % by weight of a ketone and / or aldehyde compound having a radical-polymerizable double bond c. An alkali obtained by dissolving an alkali-soluble resin obtained by copolymerizing a radical-polymerizable monomer (A1) consisting of 76 to 94 % by weight of a compound having a radical-polymerizable double bond excluding a and b in an alkaline aqueous solution. In a soluble resin solution, d. Ketone and / or aldehyde compound having radically polymerizable double bond 0 to 30% by weight e. A compound having a radical-polymerizable double bond other than d, obtained by emulsion polymerization of a radical-polymerizable monomer (A2) consisting of 70 to 100% by weight, and the sum of the weights of the b component and the d component is a. To 0.5 to 25% of the total weight of all the monomer components of A to E, A1
The weight ratio of component / A2 component is in the range of 20/80 to 80/20.

Condition II The ratio of the number of hydrazine residues of the hydrazine-based crosslinking agent contained in the aqueous printing ink composition to the total number of keto groups and aldo groups derived from the components b and d is 0. It is in the range of 1: 1.0 to 3.0: 1.0.

Further, as a preferred embodiment thereof,
~ Water-based printing ink composition for plastic film
It is related.

[0017] The c component of the aqueous resin emulsion is
A) Acrylic acid derivatives, styrene compounds and male
At least one selected from the group consisting of acid derivatives
An aqueous printing ink composition for a plastic film as described above. D component of aqueous resin emulsionAnd e componentBut,It
Each1 to 20% by weight of A2 componentAnd 80 to 99% by weight
Water-based printing ink for plastic film
Ki composition. All the monomers A1 and A2 of the aqueous resin emulsion are
The glass transition temperature of the polymer obtained by copolymerization is -40.
The above-mentioned plastis having a monomer composition in the range of ~ 50 ° C.
Water-based printing ink composition for back film. All the monomers A1 and A2 of the aqueous resin emulsion are
The glass transition temperature of the polymer obtained by copolymerization is -30.
The above-mentioned plastis having a monomer composition in the range of -30 ° C.
Water-based printing ink composition for back film. If the hydrazine-based cross-linking agent is hydrazine and / or
The above-mentioned plastis which is a compound represented by the general formula (1)
Water-based printing ink composition for back film. H₂N-NH-X-NH-NH₂                (1) (In the formula, X is an alkylene having 1 to 8 carbon atoms.
A group, or saturated or unsaturated with 1 to 10 carbon atoms
Represents the residue of a saturated dibasic acid).

In the present invention, a plastic film, especially a corona discharge-treated plastic film is printed with the water-based ink composition, and then an adhesive is applied to the printing surface, or if necessary, an anchor coating agent is applied. The present invention relates to a method for manufacturing a laminated product, which comprises laminating after coating.

[0019]

[Functions and Examples] Conventionally, an aqueous resin emulsion obtained by emulsion polymerization of a ketone and / or aldehyde compound having a radically polymerizable double bond using a surfactant as an emulsifier and a hydrazine-based crosslinking agent. The aqueous resin cross-linking system (hydrazine-based cross-linking system) is known as a binder for coating agents and adhesives.

However, this conventional type hydrazine-based cross-linking system is required to have special performance even if it can be applied to the fields of coating agents and adhesives which are applied by a method such as simple roll coater, doubzuke and spray coating. It cannot be used as is for printing ink systems.

Here, as the special performance required for the printing ink, the following 1) to 3) are typical. 1) Printability (fluidity, re-solubility) In the process of printing printing ink, the ink first transfers to the printing plate and then from the printing plate to the printing medium, but if the ink does not have good fluidity The amount of transferred ink is reduced and excellent printed matter cannot be obtained. Also, if the ink once dried on the plate is not redissolved by the newly supplied ink, clogging occurs and a cosmetic printed matter cannot be obtained. 2) Boil / retort suitable printed matter must be applicable as a packaging material for foods to applications in which boiling / retort treatment is performed in hot water for the purpose of cooking or sterilizing the contents. 3) Storage stability Normally, 6 months from the production is guaranteed as a period during which the printing ink can perform good printing, but during this period, good viscosity stability and printability must be maintained.

For these required performances, if a conventional hydrazine crosslinking system is used as an ink binder, the following drawbacks will occur. Regarding 1), not only the structural viscosity increases and the fluidity of the ink is impaired, but also the re-dissolving property decreases and an excellent printed matter cannot be obtained. Regarding 2), the emulsifier contained in the conventional type aqueous resin emulsion reduces water resistance and boil / retort suitability. Regarding 3), the keto group and the aldo group of the aqueous resin emulsion react with the hydrazine residue of the cross-linking agent with the passage of time, causing thickening / solidification and marked deterioration of printability.

On the other hand, the aqueous resin emulsion according to the present invention has a so-called hydrosol form obtained by emulsion-polymerizing a compound having a radical-polymerizable double bond in the presence of a polymer emulsifier composed of an alkali-soluble resin. is there.

In the present invention, the weight ratio of the alkali-soluble resin to the emulsion polymer is set within the most preferable range for the binder for printing inks, so that the water-based resin emulsion has advantages such as drying property and water resistance. One ideal as a water-based printing ink binder, which is different from both water-soluble resins and water-dispersible resins, or a mixture of both, having the same fluidity and re-solubility as water-soluble resins while maintaining. It is in resin form.

Further, in the crosslinking system of the present invention,
Since the high molecular emulsifier acts as a barrier layer that inhibits the reaction between the keto group or aldo group of the emulsion polymer and the hydrazine residue of the cross-linking agent, it is possible to maintain extremely stable viscosity and fluidity even over time.

In addition, the polymeric emulsifier is less likely to reduce the water resistance than ordinary emulsifiers, and the polymeric emulsifier and the crosslinking agent are cross-linked to the extent that thickening / solidification and printability are not deteriorated. By reacting, the water resistance can be dramatically improved.

That is, it is possible to cope with a number of special performances required as an aqueous printing ink {for example, 1) to 3)} only by using the aqueous resin crosslinking system of the present invention. It will be.

The present invention will be described in more detail below.

The aqueous printing ink composition for plastic films of the present invention comprises a colorant, an aqueous resin emulsion and a hydrazine-based crosslinking agent having at least two hydrazine residues in the molecule as essential components.

Colorant As the colorant used in the present invention, dyes, inorganic pigments, organic pigments and extender pigments generally used in printing inks, paints and the like can be used.

Examples of dyes that can be used here include various dyes such as azo dyes, anthraquinone dyes, indigo dyes, phthalocyanine dyes, carbonyl dyes, quinoneimine dyes, methine dyes, quinoline dyes, and nitro dyes.

Inorganic pigments that can be used include titanium oxide, red iron oxide, antimony red, cadmium red, cadmium yellow, cobalt blue, dark blue, ultramarine blue, carbon black and graphite.
Examples thereof include soluble azo pigments, insoluble azo pigments, azo lake pigments, condensed azo pigments, copper phthalocyanine pigments and condensed polycyclic pigments.

Further usable extender pigments include calcium carbonate, kaolin, clay, barium sulfate, aluminum hydroxide and talc.

Aqueous Resin Emulsion The aqueous resin emulsion used in the present invention is obtained by emulsion polymerization of a compound having a radical-polymerizable double bond in an aqueous solution of an alkali-soluble resin.

The alkali-soluble resin of the present invention comprises a component:
Carboxylic acids and / or acid anhydride having a radically polymerizable double bond, b Ingredients: ketone and / or aldehyde compounds having a radically polymerizable double bond, and c components: a radical polymerizable two except a and b components It is a copolymer resin obtained by copolymerizing a compound having a heavy bond and soluble in an alkaline aqueous solution. In the present invention, a, b
The components c and c are collectively referred to as component A1.

The carboxylic acid having a radical-polymerizable double bond as the component a is a monocarboxylic acid having about 3 to 4 carbon atoms such as acrylic acid, methacrylic acid or crotonic acid, and maleic acid. Examples include dicarboxylic acids having about 4 to 5 carbon atoms such as fumaric acid, citraconic acid, and itaconic acid, and their monoalkyl esters, monohydroxyalkyl esters, and monoamides.

The dicarboxylic acid monoesters, monohydroxyalkyl esters, and monoamides include the dicarboxylic acid component and the following monoalcohol component or carbon atom having about 1 to 18 carbon atoms. Examples thereof include a monoester compound with a diol component having about 2 to 8 atoms and a monoamide compound with an amine component having about 1 to 18 carbon atoms.

Monoalcohol component: methanol, ethanol, propanol, butanol, hexanol, octanol, decanol, dodecanol, octadecanol, etc. Diol component: ethylene glycol, propylene glycol, butylene glycol, etc. Amine component: ethylamine, diethylamine, butylamine, hexylamine , Octylamine, decylamine, octadecylamine, etc. Further, examples of the acid anhydride having a radical-polymerizable double bond as the component a include maleic anhydride, citraconic anhydride, itaconic anhydride and the like.

Among these carboxylic acids or acid anhydrides having a radical-polymerizable double bond, it is preferable to use a monocarboxylic acid, particularly acrylic acid or methacrylic acid, from the viewpoint of the emulsifying ability of the polymer emulsifier obtained. .

Next, the ketone compound having a radical-polymerizable double bond of the component b is a radical-polymerizable compound having at least one or more keto group in the molecule, and specifically, diacetone (meth ) Acrylamide, diacetone (meth) acrylate, acetonyl (meth) acrylate, vinyl alkyl ketones and the like can be mentioned.

The aldehyde compound having a radical-polymerizable double bond of the component b is a radical-polymerizable compound having at least one aldo group in the molecule, and includes acrolein, formylstyrene, and alkanal (meth). ) Acrylates and the like can be mentioned.

Next, as the c component, for example, the (meth) acrylic acid derivative, styrene compound and maleic acid derivative described below can be used.

(Meth) acrylic acid derivative: an alkyl ester of (meth) acrylic acid having 1 to 18 carbon atoms,
Alkyl amides having 1 to 18 carbon atoms, hydroxyalkyl esters having 2 to 4 carbon atoms, and the like, specifically, methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, hexyl ( (Meth) acrylate, octyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, methyl (meth) acrylamide, ethyl (meth) acrylamide, butyl (meth) acrylamide,
Hexyl (meth) acrylamide, 2-hydroxyethyl (meth) acrylate and the like can be mentioned.

Styrenic compound: styrene and its derivatives having about 8 to 10 carbon atoms, specifically α
-Methylstyrene, chlorostyrene, vinyltoluene and the like can be mentioned.

Maleic acid derivative: a dialkyl ester of maleic acid having 1 to 18 carbon atoms, having 1 carbon atom
~ 18 dialkyl amide, dihydroxy alkyl ester having 2 to 4 carbon atoms, and the like, specifically, dimethyl malate, diethyl malate, dibutyl malate, dioctyl malate, bis-2-hydroxyethyl malate, Examples thereof include maleic acid dimethylamide, maleic acid diethylamide, maleic acid dibutylamide and the like.

In the alkali-soluble resin of the present invention, the amount of the component a used is 5 to 20% by weight, and the amount of the component b used.
Is 1 to 4% by weight, and the amount of the component c used is 76 to 94% by weight.

When the amount of the component a used is less than the above range, sufficient solubility in the aqueous alkaline compound solution cannot be obtained, the stability of emulsion polymerization and the dispersion stability of the polymer are reduced, and The fluidity of the resulting printing ink is also poor. On the other hand, if it exceeds the above range, water resistance and printability are deteriorated, which is not preferable.

If the amount of component b used exceeds the above range, thickening / solidification with time and deterioration of printability are not preferable.

As a method for obtaining an alkali-soluble resin by copolymerizing the above-mentioned A1 component, a mixture of the above compounds is reacted in an organic solvent in the presence of a polymerization initiator at a predetermined temperature and a reaction time, and then an organic solvent is added. A method of distilling off the solvent can be used.

Examples of usable organic solvents include ester solvents such as ethyl acetate and isopropyl acetate, ketone solvents such as acetone and methyl ethyl ketone, lower alcohol solvents, glycols and their derivatives, and the like. Possible polymerization initiators include potassium persulfate, sodium persulfate, persulfates such as ammonium persulfate, organic peroxides such as benzoylhydroperoxide, azo compounds such as azobisisobutyronitrile, and also If necessary, a redox type initiator which is combined with a reducing agent may be mentioned.

When the present alkali-soluble resin is used as a polymeric emulsifier, the preferred molecular weight (number average molecular weight, the same applies hereinafter) is 3,000 to 100,000, more preferably 5,
It is in the range of 000 to 30,000. When the molecular weight is lower than the above range, another measure is required to give the obtained printing ink water resistance and blocking resistance, while when it is higher than the above range, the viscosity of the obtained printing ink is high. It is difficult to obtain high-concentration ink. The acid value of the alkali-soluble resin of the present invention is 50.
The range of -300 is preferable. If the acid value is less than the above range, sufficient solubility in an alkaline compound aqueous solution cannot be obtained, while if it exceeds the above range, the water resistance of the obtained printing ink,
Printability tends to decrease.

Next, as the compound (A2) having a radical-polymerizable double bond used for emulsion polymerization, the component d (used as necessary): a ketone having a radical-polymerizable double bond and / Or aldehyde compound and e component:
A compound having a radically polymerizable double bond other than the component d is used. In the present invention, the d and e components are collectively referred to as the A2 component.

Examples of the component d include the above-mentioned ketone and aldehyde compounds having a radical-polymerizable double bond.

On the other hand, as the component e, the carboxylic acid and acid anhydride having the radical-polymerizable double bond exemplified as the component a, the (meth) acrylic acid derivative exemplified as the component c, the styrene compound, Examples thereof include maleic acid derivatives, and other vinyl esters of saturated carboxylic acids having 2 to 18 carbon atoms, such as vinyl acetate, vinyl propionate, vinyl laurate and vinyl stearate.

Among these e components, from the dispersibility of the aqueous resin emulsion and the performance of the resulting aqueous printing ink,
A (meth) acrylic acid derivative and a styrene compound are preferable.

In the above A2 component, the amount of the component d used is 0 to 30% by weight, preferably 1 to 20% by weight, and the amount of the component e is 70 to 100% by weight, more preferably 80.
~ 99% by weight.

Here, if the amount of the component d used exceeds the above range, thickening / solidification with time and deterioration of printability are unfavorable.

Further, when synthesizing an aqueous resin emulsion using these components a to e, the sum of the weights of the components b and d is 0.5 with respect to the total weight of all the monomer components a to e.
It is about 25%. Here, if the sum of the weights of the b component and the d component is less than the above range, the adhesion of the ink to the plastic film and the suitability for lamination are deteriorated, which is not preferable. It is desirable to use the component b as an essential component when the water resistance of the ink is required, and the component d when the storage stability is required.

The weight ratio of A1 component / A2 component is
20 / 80-80 / 20, preferably 30 / 70-70
The range is / 30.

Here, when the weight ratio of the component A1 is lower than the above range, the re-solubility, fluidity and storage stability of the ink are lowered, while when it is higher than the above range, the water resistance of the ink is lowered. Is not preferable.

Further, the monomer composition of the aqueous resin emulsion of the present invention has a glass transition temperature of -40 to 5 when the monomers a to e used are copolymerized.
It is preferable that the temperature is adjusted to 0 ° C, more preferably to -30 to 30 ° C. If the glass transition temperature of this polymer is lower than the above range, another measure is required for the resulting printing ink to have blocking resistance, while on the other hand, if it is higher, rubbing resistance and adhesion are imparted. Another way is needed.

Generally, comparing the alkali-soluble resin and the emulsion polymer, the glass transition temperature of the alkali-soluble resin having an excellent film-forming property is increased to improve the blocking resistance, and the glass transition temperature of the emulsion polymer is lowered. By so doing, it is possible to obtain a binder resin having good film physical properties by improving the rubbing resistance and the adhesiveness.

As a method for producing an aqueous resin emulsion using the above-mentioned alkali-soluble resin obtained by copolymerizing the A1 component, the A2 component and an alkaline aqueous solution,
A method in which the alkali-soluble resin is dissolved in an alkaline aqueous solution, a mixture of the component A2 and a polymerization initiator is added dropwise, and the mixture is reacted at a predetermined temperature and reaction time can be used.

Here, as the alkali used for dissolving the alkali-soluble resin in water, ammonia,
Dimethylethanolamine, diethylethanolamine, triethylamine, tributylamine, morpholine, diethanolamine, triethanolamine and the like can be used.

The most suitable amount of alkali is about 100 to 120% of the neutralized amount of the alkali-soluble resin, and the solubility of the alkali-soluble resin tends to decrease as the amount used falls below the above range. On the other hand, even if the amount is more than the above range, the solubility is not further improved.

As the polymerization initiator, the polymerization initiator used for producing the above-mentioned alkali-soluble resin can be used.

Hydrazine-based cross-linking agent The hydrazine-based cross-linking agent used in the present invention is preferably a water-soluble polyhydrazine or hydrazide compound having two or more hydrazine residues, which is represented by the following general formula: Examples thereof include alkylenedihydrazine represented by (1), dihydrazide compounds of saturated aliphatic dibasic acid and unsaturated dibasic acid.

H ₂ N-NH-X-NH-NH ₂ (1) (In the formula, X is an alkylene group having 1 to 8 carbon atoms, or saturated or unsaturated having 1 to 10 carbon atoms. Represents the residue of a dibasic acid).

Specific examples of the alkylenedihydrazine include methylenedihydrazine, ethylenedihydrazine, propylenedihydrazine and butylenedihydrazine. As the dihydrazide compound of saturated aliphatic dibasic acid, specifically, oxalic acid dihydrazide, malonic acid dihydrazide, succinic acid dihydrazide, glutaric acid dihydrazide, adipic acid dihydrazide, sebacic acid dihydrazide and the like can be mentioned, and further unsaturated Specific examples of the dibasic acid dihydrazide compound include phthalic acid dihydrazide, fumaric acid dihydrazide, and itaconic acid dihydrazide.

Optional Ingredients The aqueous printing ink composition of the present invention has various other aqueous resins, such as cellulose resins, acrylic resins not containing keto groups or aldo groups, polyester resins, for the purpose of improving other properties. Styrene-maleic acid resin,
It is also possible to add ethylene-acrylic acid type resins and polyurethane resins. In particular, from the viewpoint of improving the pigment dispersibility, it is more preferable to use a resin soluble in an alkaline aqueous solution as the pigment dispersion resin.

Further, in order to improve the drying property of the ink and the wettability with respect to the plastic film, a lower alcohol such as methanol, ethanol, isopropanol, methoxypropanol or a water-miscible solvent such as lower alkoxypropanol, and the improvement of each performance. Therefore, various additives such as an anti-blocking agent, a defoaming agent, and a cross-linking agent other than hydrazine can be contained.

Production of Ink Composition As a method for producing an aqueous printing ink using the above materials, first, a colorant and the aqueous resin emulsion of the present invention,
The pigment dispersant can be stirred and kneaded as necessary, and then the hydrazine-based crosslinking agent and, if necessary, other components can be added and mixed to produce.

Here, as the ink composition, the content of the colorant is 0.1 to 20% by weight in the ink composition in the case of a dye,
In the case of a pigment, a suitable amount is in the range of 1 to 60% by weight.

Further, the content of the aqueous resin emargine is appropriately in the range of 5 to 30% by weight as the resin solid content in the ink composition.

If the content of the aqueous resin emulsion is less than the above range, the adhesion of the ink to the plastic film and the suitability for lamination are deteriorated, and if it is more than the above range, the fluidity of the ink is deteriorated, which is not preferable. .

Further, the content of the hydrazine-based crosslinking agent is such that the number of hydrazine residues of the hydrazine-based crosslinking agent contained in the aqueous printing ink composition: the total number of keto groups and aldo groups = 0.1: 1.0. The range is from 3.0 to 1.0.

When the content of the hydrazine-based cross-linking agent is less than this range, the adhesiveness, water resistance, laminating strength and boil retort suitability of the obtained printing ink with respect to the plastic film are deteriorated, while when it is increased, the water resistance of the printing ink is increased. Property, storage viscosity stability, printability, etc. are deteriorated, which is not preferable.

Manufacturing method of printed matter and laminating method
Method Next, a method for manufacturing a printed matter and a method for laminating a printed matter using the aqueous printing ink composition for a plastic film of the present invention will be described.

First, as the plastic film on which the aqueous printing ink composition of the present invention is printed, various plastic films such as polyolefin, modified polyolefin, polyester, nylon and polystyrene can be used. Among them, the film subjected to corona discharge treatment has a carbonyl group, and a better printed matter can be obtained.

The aqueous printing ink composition of the present invention can be printed by a flexographic or gravure printing method using a known flexographic printing machine or gravure printing machine.

Further, as a method for laminating the printed matter obtained by the above printing method, an extrusion laminating method and a dry laminating method can be used.

In the extrusion laminating method, the surface of the printed matter may be titanate-based, isocyanate-based, or
After applying an anchor coating agent such as imine-based or polybutadiene-based, it is a method of laminating a molten polymer by a conventionally known extrusion laminating machine, and further using a molten resin as an intermediate layer to form a sandwich with other materials. It can also be stacked.

As the molten resin used in the extrusion laminating method, conventionally used resins such as low density polyethylene, ethylene-vinyl acetate copolymer and polypropylene can be used. Among them, the effect of the present invention is enhanced in combination with low density polyethylene which is easily oxidized when melted to generate a carbonyl group.

Next, in the dry laminating method, a water-based, solvent-based, or solvent-free isocyanate-based adhesive or the like is applied to the surface of the printed matter, and then a film-like adhesive is formed by a conventionally known dry laminating machine. This is a method of bonding a polymer.

As the film-like polymer used in the dry laminating method, polyethylene, polypropylene and the like can be used. Especially in the case of a laminated product used for retort applications, it is laminated with a substrate for imparting hot water resistance. Aluminum foil can be laminated between plastic films.

In terms of safety and health, environmental problems, etc.,
In order to obtain a laminated product without using any organic solvent in the manufacturing process, it is preferable to use an aqueous or solvent-free adhesive.

The laminated product obtained by the above method has a high laminating strength and can be applied to the use of boil retort. By combining with a solvent-free laminating adhesive, it is possible to obtain a laminated product suitably from the viewpoint of safety and hygiene, environmental problems, etc. without using any organic solvent in the manufacturing process.

[Examples] The present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

The parts and% in the examples and the like represent parts by weight and% by weight, unless otherwise specified.

<Production Example of Alkali-Soluble Resin A1> 100 parts of propylene glycol monomethyl ether acetate (PMAc) was charged into a four-necked flask equipped with a stirrer, a thermometer, a nitrogen gas introduction tube, and a dropping funnel, and the atmosphere was replaced with nitrogen gas. Then it was heated to 145 ° C.

Then, while introducing nitrogen gas, the mixture of the monomer and the di-t-butylperoxide having the composition shown in Table 1 was dropped from the dropping funnel over 3 hours. After completion of the dropping, the reaction was completed by polymerizing for 2 hours while maintaining the same temperature to obtain a PMAc solution of each copolymer.

The obtained copolymer solution was heated to 180 ° C., distilled under normal pressure, and further heated to 190 ° C. to distill off PMAc under reduced pressure distillation, and to obtain a solid copolymer which is soluble in an alkaline aqueous solution. Combined 1 to 20 were obtained.

[0093]

[Table 1]

<Production Example of Aqueous Resin Emulsion> Stirrer,
A four-necked flask equipped with a thermometer, a nitrogen gas introduction tube, and a dropping funnel was charged with crushed solid copolymers 1 to 20 and 1.2 times the neutralization amount of ammonia of the solid copolymer used. The already dissolved ammonia water is shown in Tables 2-1 and 2-2.
Then, the mixture was heated to 80 ° C. to dissolve the solid copolymer, and then a mixture of the monomer of A2 and ditertiarybutyl peroxide was added dropwise over 3 hours while introducing nitrogen gas. After completion of the dropping, the reaction was completed by polymerizing for 2 hours, and an appropriate amount of water was added to the mixture to add an aqueous resin emulsion No. (Aqueous resin Em No.) 1 to 31 were obtained.

[0095]

[Table 2]

[0096]

[Table 3]

Examples 1 to 5 and Comparative Examples 1 to 12 ,
In addition, according to the formulation of Reference Examples 1 to 20 and Tables 3-1 to 3-3, first, a mixture of a pigment, a water-soluble resin for kneading meat and an appropriate amount of water was kneaded with a red devil type paint conditioner for 30 minutes, and other predetermined amounts were used. The materials were added and mixed to prepare the aqueous printing inks of Examples 1 to 5 and Comparative Examples 1 to 12 and Reference Examples 1 to 20 .

As a pigment, lionol blue FG-
7330 (manufactured by Toyo Ink Mfg. Co., Ltd.) as a resin varnish for pigment dispersion, John Cryl J-61 (manufactured by Johnson Polymer Co., Ltd.), adipic acid dihydrazide (ADH) as a hydrazine-based cross-linking agent, and isopropyl alcohol (IPA) as an organic solvent. It was used.

Examples 1 to 5 and Comparative Examples 1 to 12 ,
Also , the following tests were performed on the water-based printing inks obtained in Reference Examples 1 to 20 , and the results are shown in Tables 3-1 to 3-3.
Described in.

Blocking resistance test method Each test ink was printed on a biaxially oriented polypropylene film (hereinafter referred to as an OPP film) by a gravure proofing machine, and the printing surfaces of the obtained OPP film printed matter were overlapped and sandwiched between vises. 2 under the temperature condition of ℃
It was left for 4 hours. The sample was peeled off by hand, and the blocking resistance was evaluated from the rate at which the ink was removed from the printed film. Evaluation Criteria A: No ink is removed from the film. B: Ink is taken from the film in a range of less than 20%. C: 20% or more of ink is taken from the film.

Heat resistance test method OP of each test ink by gravure proofing machine
An aluminum foil was applied to the printed surface of the P film printed matter, heated with a heat sealer and pressed at a pressure of 2.0 kg / cm @ 2, and the heat resistance was evaluated from the temperature at which the ink was taken on the aluminum foil. Evaluation Criteria A: Ink is not removed from the aluminum foil even at 180 ° C. B: The ink is taken on the aluminum foil in the range of 150 to 180 ° C. C: Ink is removed on the aluminum foil at a temperature lower than 150 ° C.

Heat-resistant water whitening test method OP of each test ink by gravure proofing machine
The P film printed matter was immersed in hot water at 70 ° C. for 1 hour, and the whitening state of the printed matter when taken out was visually observed to evaluate the hot water whitening property. Evaluation Criteria A: No whitening occurs. B: Slightly whitened. C: Significant whitening.

Water Rubbing Resistance Test Method OP of each test ink by gravure proofing machine
After the P film printed matter was wetted with water, it was strongly rubbed 10 times to evaluate the water rub resistance from the state of ink peeling. Evaluation Criteria A: No ink is peeled off from the film. B: The ink is peeled off from the film in the range of less than 20%. C: Ink is peeled off from the film at 20% or more and less than 50%. D: 50% or more of the ink is peeled off from the film.

Adhesion test method OP of each test ink by gravure proofing machine
After sticking cellophane tape (TE-12 manufactured by Nichiban Co., Ltd.) on the printed surface of the P film printed matter and pressing it with a finger three times, peel off the cellophane tape from the printed surface, and the adhesiveness is determined from the rate at which the ink is peeled from the film. Was evaluated. Evaluation Criteria A: No ink is peeled off from the film. B: The ink is peeled off from the film in the range of less than 20%. C: 20% or more of the ink peels from the film.

Re-solubility test method OP of each test ink was measured by a gravure proofing machine.
After printing on the P film for a while, the operation was stopped and the state was left as it was for 60 seconds. After that, printing was restarted, and re-dissolvability was evaluated from the number of pitches until a normal printed matter was obtained. Evaluation Criteria A: Return to normal within 20 pitches. B: Return to normal at 21 to 50 pitches. C: It does not return to normal even if it exceeds 50 pitches.

Swimming (uneven printing) test method OP of each test ink by gravure proofing machine
The printing unevenness of the P film printed matter was visually observed to evaluate swimming. Evaluation Criteria A: No print unevenness is observed. B: Some print unevenness is observed. C: Print unevenness is severe.

Flowability Test Method Using a Brookfield type (B type) viscometer,
The viscosities of the test inks were measured at rotational speeds of 30 rpm and 60 rpm, respectively, and the viscosity ratios (viscosity at 30 rpm /
The fluidity was evaluated by (viscosity at 60 rpm). Evaluation Criteria A: A viscosity ratio of 0.8 or more and less than 1.2. B: A viscosity ratio of 0.5 or more and less than 0.8 or 1.2 or more and less than 2.0. C: A viscosity ratio of less than 0.5 or 2.0 or more.

Gloss test method OP of each test ink by gravure proofing machine
The gloss of the P film print was measured with a gloss meter (60 °), and the gloss was evaluated from the value. Evaluation Criteria A: Gloss value of 60 or more. B: A gloss value of 50 or more and less than 60. C: A gloss value of less than 50.

Storage stability test method The test ink was stored for 7 days under the temperature condition of 40 ° C., and the storage stability was evaluated from the ratio of the viscosity after storage and the initial viscosity. Viscosity ratio = viscosity after storage at 40 ° C. for 7 days / initial viscosity evaluation standard A: viscosity ratio of 1.5 or less. B: A viscosity ratio of more than 1.5 and 4.0 or less. C: A viscosity ratio of more than 4.0.

Extrusion Laminate Strength Test Method OP of each test ink by gravure proofing machine
Imine-based anchor coating agent (EL-420 manufactured by Toyo Morton Co., Ltd.) was applied to the P film printed matter, and polyethylene melted at 345 ° C. by an extrusion laminating machine was 30 μm.
A laminated product was obtained by laminating the films with a thickness of m.

Also, a polyethylene terephthalate film printed matter of each test ink by a gravure proofing machine (hereinafter,
Isocyanate type anchor coating agent (Toyo Morton Co., Ltd. EL-433A /
C) was applied, and polyethylene melted at 350 ° C. with an extrusion laminating machine was laminated to a film thickness of 45 μm to obtain a laminated product. These laminates at 40 ° C for 3
After leaving it for a day, it is cut into 15 mm width and manufactured by Yasuda Seiki Co., Ltd.
The T-type peel strength was measured using a peeling tester. Evaluation Criteria The actually measured value of the peel strength (g / 15 mm) is described.

Dry Lamination Test Test Method OP of each test ink by gravure proofing machine
P film printed matter, PET film printed matter, polyurethane adhesive (Toyo Morton Co., Ltd. Adcoat 308 /
CAT-8D) was applied, and then an unstretched polypropylene film having a thickness of 30 μm (hereinafter referred to as CPP film) (P-1128 manufactured by Toyobo Co., Ltd.) was laminated to obtain a laminated product. 15mm of these laminates
Cut to width and use a peeling tester manufactured by Yasuda Seiki Co., Ltd.
The mold peel strength was measured. Evaluation Criteria The actually measured value of the peel strength (g / 15 mm) is described.

Retort suitability test method PE of each test ink by gravure proofing machine
A polyurethane adhesive (A-515 / A-50 manufactured by Takeda Pharmaceutical Co., Ltd.) was applied to the T film printed matter, and then 6
A 0 μm thick CPP film (Trefan NZK-93K manufactured by Toray Gosei Co., Ltd.) was laminated to obtain a laminated product. This laminated product is made into a bag, filled with a content of a mixture of water / salad oil, melt-sealed, and subjected to hot water treatment in pressurized hot water of 120 ° C. for 30 minutes to suit the retort suitability of the surface of the laminated product. Was evaluated. Evaluation Criteria A: No abnormality is observed on the surface. B: A slight pinhole-like lamella float was observed on the surface, or a lamella float with a length of less than 5 mm was observed. C: Is there a pinhole-like lamella float on the entire surface?
It is possible to see a floating lami with a length of 5 mm or more.

Here, except for the water-rubbing resistance, the practical range is B or more as the evaluation standard and the water-rubbing resistance is C or more as the evaluation standard.

[0115]

[Table 4]

[0116]

[Table 5]

[0117]

[Table 6]

[0118]

EFFECTS OF THE INVENTION As specifically shown above, the aqueous printing ink composition of the present invention is excellent in water resistance, various printability, adhesiveness to various plastic films and long-term storage stability. , With higher laminating strength and retort suitability.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Maeda 1-23-37, Edobori, Nishi-ku, Osaka City, Sakata Inx Co., Ltd. (56) References JP-A-6-179844 (JP, A) JP-A-6- 155694 (JP, A) JP 5-98071 (JP, A) JP 64-48801 (JP, A) JP 58-104902 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) C09D 11/00-11/20 C08J 7/00 303-7/18

Claims (8)

(57) [Claims] 1. A colorant, an aqueous resin emulsion, and a hydrazine-based cross-linking agent having at least two hydrazine residues in the molecule are essential components, and the following conditions I and
A water-based printing ink composition for a plastic film, which satisfies II. Condition I The aqueous resin emulsion comprises a. 5 to 20 % by weight of carboxylic acid and / or acid anhydride having a radical-polymerizable double bond b. 1 to 4 % by weight of a ketone and / or aldehyde compound having a radical-polymerizable double bond c. An alkali obtained by dissolving an alkali-soluble resin obtained by copolymerizing a radical-polymerizable monomer (A1) consisting of 76 to 94 % by weight of a compound having a radical-polymerizable double bond excluding a and b in an alkaline aqueous solution. In a soluble resin solution, d. Ketone and / or aldehyde compound having radically polymerizable double bond 0 to 30% by weight e. A compound having a radical-polymerizable double bond excluding d, which is obtained by emulsion-polymerizing a radical-polymerizable monomer (A2) consisting of 70 to 100% by weight, and the sum of the weights of the b component and the d component is a. To 0.5 to 25% with respect to the sum of the weights of all the monomer components of e, and the weight ratio of A1 component / A2 component is 20/80 to 80/2.
The range is 0. Condition II The number of hydrazine residues of the hydrazine-based cross-linking agent contained in the aqueous printing ink composition, the above-mentioned b component and d
The ratio with the total number of keto groups and aldo groups derived from the components is in the range of 0.1: 1.0 to 3.0: 1.0. 2. The component c of the aqueous resin emulsion comprises:
(Meth) acrylic acid derivatives, styrene compounds and at least one kind of claim 1 Symbol mounting plastic film water based printing ink composition selected from the group consisting of maleic acid derivatives. 3. The component d of the aqueous resin emulsion and
Fine e component, 1 to 20% by weight of component A2, respectively, and
80 to 99 is in the range of weight percent according to claim 1 or 2 plastic film water based printing ink compositions described. 4. The monomer composition having a glass transition temperature of -40 to 50 ° C., which is obtained by copolymerizing all the monomer components A1 and A2 of the aqueous resin emulsion. Item 1. A water-based printing ink composition for plastic film according to any one of items 1 to 3 . 5. The glass transition temperature of the polymer obtained by copolymerizing all the monomer components A1 and A2 of the aqueous resin emulsion has a monomer composition in the range of −30 to 30 ° C. Item 1. A water-based printing ink composition for plastic film according to any one of items 1 to 4 . Wherein said hydrazine-based crosslinking agent, hydrazine and / or the general formula (1) is a compound represented by the claims 1 to plastic film water based printing ink composition according to any of the 5 below . _{H 2 N-NH-X-} NH-NH 2 (1) ( wherein, X is a saturated or unsaturated dibasic acid having an alkylene group or from 1 to 10 carbon atoms, having 1 to 8 carbon atoms Represents the residue of). 7. The plastic film according to any one of claims 1 to 6.
After printing the water-based ink composition for a plastic film according to any one of the following, characterized by applying an adhesive to the printing surface, or after applying an anchor coating agent if necessary, laminating A method for manufacturing a laminated product. 8. The method for producing a laminated product according to claim 7, wherein a corona discharge treated plastic film is used.