Liquid ink composition

Abstract

To provide a liquid ink composition capable of enhancing adhesiveness and laminate strength particularly to olefin films such as polypropylene films and polyethylene films, while retaining superior adhesion to various films.SOLUTION: A liquid ink composition comprises a binder resin, at least one selected from polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2), and an organic solvent (C). The polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2) have a number average molecular weight of 500 or more and 50000 or less, and the content of the polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2) is 0.05 to 10.0 mass% relative to the total solid content of the liquid ink composition.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a liquid ink composition for gravure ink and flexo ink for use in laminating applications for flexible packaging. In addition to pet films, nylon films, inorganic and organic barrier layers, and various barrier films coated with coating agents, the present invention particularly relates to a liquid ink composition suitable for polypropylene films and polyethylene films, which are prone to reduced adhesion.

Background Art

[0002] In recent years, in the flexible packaging industry, the movement to enhance the recyclability of packages after use by consumers has been accelerating. In order to improve recyclability, the development of so-called monomaterial packages composed only of olefins (polypropylene, polyethylene) has been particularly active.

[0003] Liquid inks for laminating applications used in the manufacture of flexible packaging materials mainly use urethane resins or urethane-urea resins. Furthermore, in recent years, the use of aromatic solvents such as toluene and ketone solvents such as methyl ethyl ketone has been increasingly restricted from the perspectives of work hygiene during printing and the harmfulness of packaging materials. For example, in the case of de-aromatic solvent- and ketone solvent-based liquid inks, from the viewpoint of printing suitability, esters such as ethyl acetate and propyl acetate, alcohol solvents such as isopropyl alcohol and normal propyl alcohol, or mixed solvents thereof are used instead of aromatic and ketone solvents as solvents.

[0004] Furthermore, in response to the trend of the times, such as the construction of a circular society that reduces substances that can have an adverse impact on the human body or the environment, as represented by the Sustainable Development Goals, regulations regarding packaging materials that use plastic have become stricter globally. In particular, in recent years, there has been a demand for stricter regulations on the components used in packaging materials and their migration to food. In addition, the movement to eliminate plastic has also accelerated, and the demand for the recyclability of packaging materials has increased. Therefore, in the development of products related to packaging materials, including inks, it has become necessary to design packaging material constituent materials using materials that ensure safety for the human body or the environment.

[0005] Among them, vinyl chloride-vinyl acetate copolymer is a substance that is suspected of inhibiting the recycling of packaging materials for the following reasons (a) and (b).

[0006] (a) Chlorine-based resins such as vinyl chloride can cause corrosion of equipment or piping due to the elimination of hydrogen chloride and the generation of hydrochloric acid in the thermal decomposition process of recycling.

[0007] (b) In thermal recycling, which reuses the energy generated when waste is incinerated, when chlorine-based resins are incinerated, environmental hormones such as dioxins can be emitted.

[0008] Therefore, in the future, the development of environmentally friendly materials, such as making chlorine-free chlorine-based resins free, is required. However, it is difficult to satisfy various physical properties such as the dispersibility of the ink composition and the adhesion to the film in such environmentally friendly materials.

[0009] In the manufacture of flexible packaging materials, various films such as polyethylene terephthalate, polypropylene, nylon, and high-functional films with barrier properties are used, and printing inks are required to have adhesion to these various printing substrates. In particular, the adhesion to polypropylene films and polyethylene films is often insufficient. From the perspective of imparting recyclability as described above, inks suitable for olefin-based monomaterials are demanded in the market.

[0010] For example, Patent Document 1 and Patent Document 2 describe inventions in which polydiene polyol or hydrogenated polydiene diol is introduced into urethane. However, since the polyol is incorporated into the urethane resin in Patent Document 1 and Patent Document 2, the adhesion to the olefin film is not satisfactory. Therefore, further improvement in adhesion is desired using diverse ink materials and film substrates from the viewpoint of environmental response and the like.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0012] An object of the present invention is to provide a liquid ink composition that can achieve good adhesion and laminate strength to olefin films such as polypropylene films and polyethylene films, while maintaining excellent adhesion to various films.

Means for Solving the Problems

[0013] The present invention contains a binder resin, at least one selected from polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2), and an organic solvent (C). Polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2) have a number average molecular weight of 500 to 50,000 and are contained in an amount of 0.05 to 10.0% by mass based on the total solid content of the liquid ink composition, thereby overcoming the above problems.

[0014] Furthermore, the present invention relates to a liquid ink composition containing a polyurethane resin (D) as the binder resin.

[0015] Furthermore, the present invention relates to a liquid ink composition containing a resin (E) having a glass transition temperature (Tg) of 40°C or higher.

[0016] Furthermore, the present invention relates to a liquid ink composition in which the polyurethane resin (D) has a urea bond.

[0017] Furthermore, the present invention relates to a liquid ink composition in which the polyurethane resin (D) uses a polyether resin as a reaction raw material, and the polyether resin is 1 to 50% by mass based on the total amount of the polyurethane resin (D).

[0018] Furthermore, the present invention relates to a liquid ink composition in which the urethane bond concentration of the polyurethane resin (D) is 0.3 to 2.0 mmol / g.

[0019] Furthermore, the present invention relates to a liquid ink composition in which the resin (E) having a glass transition temperature (Tg) of 40°C or higher is any one or more of a vinyl chloride-vinyl acetate copolymer resin having a hydroxyl group, a polyvinyl butyral resin, and a cellulose-based resin.

[0020] Furthermore, the present invention relates to a liquid ink composition in which the organic solvent (C) does not contain an aromatic organic solvent and / or a ketone-based solvent.

[0021] Furthermore, the present invention relates to a printed matter obtained by printing the liquid ink composition.

[0022] Furthermore, the present invention relates to a printed matter in which the printed matter is a printed matter obtained by printing the liquid ink composition on a plastic film, and the plastic film is a polyolefin resin.

[0023] Furthermore, the present invention relates to a laminate laminate having the printed matter.

Advantages of the Invention

[0024] According to the present invention, a liquid ink composition is obtained which has adhesiveness to a wide range of films, laminate strength, extrusion laminate strength, and good printability, and particularly excellent adhesion to olefin films and laminate strength. Further, according to the present invention, even in an environment-friendly liquid ink composition containing no vinyl chloride-vinyl acetate copolymer and reducing or containing no chlorine-based resin, a liquid ink composition can be obtained which has adhesiveness to a wide range of films including olefin films, laminate strength, extrusion laminate strength, and good printability.

Embodiments for Carrying Out the Invention

[0025] The present invention will be described in detail. In the following description, all "inks" refer to "printing inks". Also, "parts" and "%" all refer to "parts by mass" and "% by mass".

[0026] The liquid ink composition of the present invention essentially contains a binder resin, at least one selected from polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2), and an organic solvent (C).

[0027] Specifically, the liquid ink composition of the present invention is prepared by premixing at least one selected from the above binder resin, polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2) with various organic solvents such as ethyl acetate, methyl ethyl ketone, toluene, and IPA. In the case of a varnish composition, the varnish composition can be obtained by adding various additives while stirring the solution with a dispersion stirrer and further stirring. In the case of an ink composition, the ink composition can be obtained by adding a colorant and dispersing it sufficiently.

[0028] The polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2) used in the present invention have a hydrocarbon-based main component. They have excellent affinity for hydrocarbon-based films (e.g., polyolefin films such as polypropylene films and polyethylene films), resulting in excellent adhesion and laminate strength, and particularly improved extrusion laminate strength.

[0029] These number average molecular weights are from 500 to 5000 from the viewpoint of adhesion, and the range of 500 to 3000 is preferable for further improving compatibility. When the molecular weight is less than 500, the blocking resistance is particularly poor, and when it exceeds 5000, the compatibility becomes poor.

[0030] As commercially available products, the polybutadiene (A1) includes NISSO PB B-1000, B-2000, B-3000 manufactured by Nippon Soda Co., Ltd.; the polybutadiene diol (A2) includes Poly bd R15-HT, R45-HT manufactured by Idemitsu Kosan Co., Ltd., Krasol LBH 2000, LBH-P2000, LBH-3000, LBH-P3000 manufactured by Cray Valley, NISSO PB G-1000, G-2000, G-3000 manufactured by Nippon Soda Co., Ltd.; the hydrogenated polybutadiene diol (A3) includes NISSO PB GI-1000, GI-2000, GI-3000 manufactured by Nippon Soda Co., Ltd., Poly Tail H manufactured by Mitsubishi Chemical Corporation, Krasol HLBH P-2000, P-3000 manufactured by Cray Valley; the polyisoprene polyol (B1) includes Poly ip manufactured by Idemitsu Kosan Co., Ltd.; and the hydrogenated polyisoprene polyol (B2) includes Epole manufactured by Idemitsu Kosan Co., Ltd.

[0031] The polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2) may be used alone or in combination of two or more.

[0032] The content of polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2) is preferably 0.05 to 10.0% by mass, more preferably 0.1 to 5% by mass, and still more preferably 0.2 to 1.0% by mass based on the total solid content of the liquid ink composition.

[0033] (Organic solvent (C)) The liquid ink composition of the present invention contains an organic solvent (C). Various organic solvents can be used as the organic solvent (C). For example, aromatic organic solvents such as toluene and xylene, ketone solvents such as acetone, methyl ethyl ketone, and methyl isobutyl ketone, ester solvents such as ethyl acetate, n-propyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate, and alcohol solvents such as n-propanol, isopropanol, n-butanol, and propylene glycol monomethyl ether can be mentioned, and these can be used alone or as a mixture of two or more. In recent years, from the perspective of the working environment, it is more preferable not to use aromatic solvents such as toluene and xylene or ketone solvents.

[0034] (Binder resin) The liquid ink composition of the present invention contains a binder resin. The "binder resin" in this specification refers to a resin excluding polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2) among the binder resins contained in the ink or ink composition. Further, the binder resin may be in a state dissolved in a solvent or in an emulsion state. There is no particular limitation on the binder resin, and known materials can be used.

[0035] Among them, it is preferable to contain a polyurethane resin (D) as the binder resin. As the polyurethane resin (D), a publicly known and commonly used polyurethane resin can be used. On the other hand, it is preferable to use a polyurethane resin having a urea bond. Further, it is preferable to use a polyurethane resin using a polyether resin as a reaction raw material. In particular, it is preferable to use a polyether resin in a proportion of 1 to 50% by mass based on the total amount of the polyurethane resin (D), and it is more preferable to use a polyether resin in a proportion of 3 to 30% by mass. Further, it is preferable to use a polyurethane resin having a urethane bond concentration of 0.3 to 2.0 mmol / g.

[0036] In addition, it is preferable that the number average molecular weight of the polyether resin is 100 to 3500. Details will be described later. Examples of the polyether polyol include polyether polyols that are polymers or copolymers of ethylene oxide, propylene oxide, tetrahydrofuran, and the like. Specifically, publicly known and commonly used ones such as polyethylene glycol, polypropylene glycol, and polytetramethylene glycol may be used. By containing the polyether resin within the above range, the adhesion on a particularly high-functional barrier film is significantly improved, and as a result, the blocking resistance and the laminate strength become excellent.

[0037] When the number average molecular weight of the polyether resin is less than 100, the film of the polyurethane resin (DA) tends to become hard and the adhesiveness to the film tends to decrease. When the number average molecular weight is greater than 3500, the film of the polyurethane resin tends to become fragile and the blocking resistance of the ink film decreases. When the amount of the polyether polyol is less than 1 part by mass with respect to 100 parts by mass of the polyurethane resin (D), the solubility of the polyurethane resin (D) in ketone, ester, and alcohol solvents tends to decrease. Also, the re-solubility of the ink film in the solvent decreases, and the tone reproducibility of the printed matter tends to decrease. Further, when it exceeds 50 parts by mass, the ink film becomes overly soft and tends to have poor blocking resistance.

[0038] In addition, when the polyurethane resin (D) has a urea bond, the cohesive force between the resins is improved, and particularly the blocking resistance becomes excellent.

[0039] When the urethane bond concentration of the polyurethane resin (D) is in the range of 0.3 to 2.0 mmol / g, the adhesion on the olefin film and the extrusion lamination strength are particularly excellent. When the urethane bond concentration is 0.5 mmol / g or more, the extrusion lamination strength is particularly excellent.

[0040] As the co-polyol optionally used for the polyurethane resin (D) used in the liquid ink composition of the present invention, various known polyols generally used in the production of polyurethane resins can be used, and one kind or two or more kinds may be used in combination.For example, polyether polyols of polymers or copolymers such as methylene oxide, ethylene oxide, tetrahydrofuran (1); saturated or unsaturated low molecular weight polyols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2-ethyl-2-butyl-1,3-propanediol, 1,3-butanediol, 1,4-butanediol, neopentyl glycol, pentanediol, 3-methyl-1,5-pentanediol, hexanediol, octanediol, 1,4-butynediol, 1,4-butylene diol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, pentaerythritol (2); polyester polyols (3) obtained by dehydration condensation or polymerization of these low molecular weight polyols (2) with polycarboxylic acids such as adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, trimellitic acid, pyromellitic acid or anhydrides thereof; polyester polyols (4) obtained by ring-opening polymerization of cyclic ester compounds such as lactones such as polycaprolactone, polyvalerolactone, poly(β-methyl-γ-valerolactone); polycarbonate polyols (5) obtained by reaction of the above low molecular weight polyols (2) etc. with, for example, dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene etc.; polybutadiene glycols (6); glycols (7) obtained by adding ethylene oxide or propylene oxide to bisphenol A; acrylic polyols (8) obtained by copolymerizing one or more hydroxyethyl, hydroxypropyl acrylate, hydroxybutyl acrylate etc. in one molecule, or corresponding methacrylic acid derivatives thereof, with, for example, acrylic acid, methacrylic acid or esters thereof, etc. may be mentioned.

[0041] Further, among the polyester polyols (3), the polymer diol obtained from diols (glycols) and dibasic acids can have up to 5 mol% of the diols replaced with the low molecular weight polyols (2) having three or more hydroxyl groups.

[0042] Examples of the diisocyanate compound used for the polyurethane resin ((D)) in the ink composition for lamination for flexible packaging of the present invention include various known aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, etc. generally used in the production of polyurethane resins. For example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl isocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, tolylene diisocyanate, butane-1,4-diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, cyclohexane-1,4-diisocyanate, xylylene diisocyanate, isophorone diisocyanate, dimer diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis(isocyanatomethyl)cyclohexane, methylcyclohexane diisocyanate, norbornane diisocyanate, m-tetramethylxylylene diisocyanate, 4,4-diphenylmethane diisocyanate, tolylene diisocyanate, bis-chloromethyl-diphenylmethane-diisocyanate, 2,6-diisocyanate-benzyl chloride, and dimer diisocyanate obtained by converting the carboxyl group of dimer acid into an isocyanate group. These diisocyanate compounds can be used alone or in admixture of two or more.

[0043] As the chain extender used for the polyurethane resin (D) in the liquid ink composition of the present invention, in addition to ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, etc., amines having a hydroxyl group in the molecule such as 2-hydroxyethylethylenediamine, 2-hydroxyethylpropyldiamine, 2-hydroxyethylpropylenediamine, di-2-hydroxyethylethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethylpropylenediamine, 2-hydroxypyrropylethylenediamine, di-2-hydroxypyrropylethylenediamine, di-2-hydroxypropylethylenediamine can also be used. These chain extenders can be used alone or in combination of two or more.

[0044] Also, as a terminal blocking agent for the purpose of terminating the reaction, a monovalent active hydrogen compound can be used. Examples of such compounds include dialkylamines such as di-n-butylamine and alcohols such as ethanol and isopropyl alcohol. Further, especially when it is desired to introduce a carboxyl group into the polyurethane resin, amino acids such as glycine and L-alanine can be used as the reaction terminator. These terminal blocking agents can be used alone or in combination of two or more.

[0045] The polyurethane resin (D) in the liquid ink composition of the present invention is obtained, for example, by reacting polypropylene glycol and a combined polyol with a diisocyanate compound at a ratio such that the isocyanate groups are in excess to obtain a prepolymer having terminal isocyanate groups, and then reacting the obtained prepolymer in a suitable solvent, that is, an ester solvent such as ethyl acetate, propyl acetate, or butyl acetate, which is commonly used as a solvent for gravure ink; a ketone solvent such as acetone, methyl ethyl ketone, or methyl isobutyl ketone; an alcohol solvent such as methanol, ethanol, isopropyl alcohol, or n-butanol; a hydrocarbon solvent such as toluene, xylene, methylcyclohexane, or ethylcyclohexane; or a mixed solvent thereof, by a two-step method of reacting with a chain extender and / or a terminal blocking agent, or by a one-step method of reacting polypropylene glycol, a combined polyol, a diisocyanate compound, a chain extender, and / or a terminal blocking agent all at once in a suitable solvent among the above. Among these methods, to obtain a uniform polyurethane resin, it is preferably produced by the two-step method. Further, when the polyurethane resin is produced by the two-step method, it is preferable to react such that the total (equivalent ratio) of the amino groups of the chain extender and / or the terminal blocking agent is in the ratio of 1 / 0.9 to 1.3. When the equivalent ratio of the isocyanate group to the amino group is less than 1 / 1.3, the chain extender and / or the terminal blocking agent may remain unreacted, and the polyurethane resin may turn yellow or an odor may occur after printing. Furthermore, in recent years, from the perspective of the working environment, it is more preferable not to use aromatic solvents such as toluene and xylene or ketone solvents.

[0046] The weight average molecular weight of the polyurethane resin (D) thus obtained is preferably in the range of 15,000 to 150,000, more preferably in the range of 15,000 to 100,000. When the weight average molecular weight of the polyurethane resin is less than 15,000, the blocking resistance, the strength of the printed film, the oil resistance, etc. of the obtained ink composition tend to be low, and when it exceeds 100,000, the viscosity of the obtained ink composition tends to be high and the gloss of the printed film tends to be low.

[0047] The content of the polyurethane resin (D) used in the liquid ink composition of the present invention in the ink is preferably 4% by mass or more based on the total mass of the ink from the viewpoint of sufficiently ensuring the adhesiveness of the ink to the printing object, and 25% by mass or less from the viewpoints of appropriate ink viscosity and work efficiency during ink production and printing, and more preferably in the range of 6 to 15% by mass.

[0048] The urethane bond concentration can be calculated by the following formula (1). Urethane bond concentration = {(W1 × OH1 + W2 × OH2 + ··· + W i × OH i ) × 1000} / (56100 × S) Formula (1) In formula (1), each is as follows. When using a plurality of polyols, calculate them as polyol 1, polyol 2 to polyol i respectively. W1: Mass of polyol 1 OH1: Hydroxyl value of polyol 1 W2: Mass of polyol 2 OH2: Hydroxyl value of polyol 2 W i : Mass of polyol i OH i : Hydroxyl value of polyol i S: Mass of urethane resin solid content The binder resin may contain other binder resins other than the urethane resin component. As the other binder resin, it is preferable to contain a resin (E) having a glass transition temperature (Tg) of 40°C or higher.

[0049] (Resin (E) having a glass transition temperature (Tg) of 40°C or higher) The ink composition for laminate for flexible packaging of the present embodiment may contain a resin (E) having a glass transition temperature (Tg) of 40°C or higher as needed. Thereby, good blocking resistance, redissolvability, and ink film physical properties can be exhibited.

[0050] As the resin (E) having a glass transition temperature (Tg) of 40°C or higher, there is no particular limitation as long as the glass transition temperature (Tg) is 40°C or higher, but it is preferably one or more selected from the group consisting of polyvinyl butyral resins, cellulose resins, and vinyl chloride-vinyl acetate copolymer resins. For example, when emphasizing environmental load reduction, as the resin (E) having a glass transition temperature (Tg) of 40°C or higher, a polyvinyl butyral resin or a cellulose resin is preferable. On the other hand, when emphasizing dispersibility, a polyvinyl butyral resin or a vinyl chloride-vinyl acetate copolymer resin is preferable.

[0051] In the present embodiment, with respect to the total resin solid content (100% by mass) of the ink composition, the lower limit of the content of the resin (E) having a glass transition temperature (Tg) of 40°C or higher is preferably 0.1% by mass or more, 0.3% by mass or more, 0.5% by mass or more, 1.7% by mass or more, 2.2% by mass or more, or 2.8% by mass or more. On the other hand, the upper limit of the content of the resin (E) having a glass transition temperature (Tg) of 40°C or higher is preferably 30% by mass or less, 28% by mass or less, 27% by mass or less, 26% by mass or less, 25% by mass or less, or 22% by mass or less. When the content range of the resin (E) having a glass transition temperature (Tg) of 40°C or higher is 0.1% by mass or more and 30% by mass or less, it is preferable from the viewpoints of improving film physical properties such as blocking resistance and ensuring pigment dispersibility. The above upper and lower limits can be appropriately combined.

[0052] Hereinafter, polyvinyl butyral resins, cellulose resins, and vinyl chloride-vinyl acetate copolymer resins, which are preferred embodiments of the resin (E) having a glass transition temperature (Tg) of 40°C or higher, will be described in detail.

[0053] <Polyvinyl butyral resin> The ink composition for lamination for flexible packaging of the present embodiment preferably contains a polyvinyl butyral resin as a resin (E) having a glass transition temperature (Tg) of 40°C or higher. Since the polyvinyl butyral resin has binding ability and dispersibility as a binder resin and its constituent elements are only carbon atoms, hydrogen atoms, and oxygen atoms, it has the effect of being more environmentally friendly than vinyl chloride-vinyl acetate copolymer resin. Further, when the ink composition for lamination for flexible packaging contains a pigment, when the pigment is dispersed by kneading with the polyvinyl butyral resin, any suitable group among butyral groups, polyvinyl alcohol residues, and vinyl acetate residues is adsorbed on the pigment, and steric hindrance occurs due to the bulky butyral group, so it has better dispersion stability than dispersing the pigment with a polyurethane resin (A).

[0054] As the polyvinyl butyral resin of the present embodiment, known resins can be used without particular limitation. Generally, as the polyvinyl butyral resin, a reaction product obtained by acetalizing polyvinyl alcohol with an aldehyde compound such as butyraldehyde by a known reaction can be used. The polyvinyl butyral resin of the present embodiment has the following general formula (iii-1):

[0055] [Chemical formula]

[0056] (In the above general formula (iii-1), n1 and n2 are each independently an integer of 1 or more, and R 1 represents a hydrogen atom or a hydrocarbon group having 1 to 12 carbon atoms.) Preferably has a partial structure represented by

[0057] In the above general formula (iii-1), R 1 preferably represents a hydrogen atom or a hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrogen atom or a hydrocarbon group having 1 to 7 carbon atoms, and still more preferably a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms.

[0058] The hydrocarbon group includes an alkyl group, an alkenyl group, an aryl group, or an aralkyl group, and may be linear, branched, or cyclic. Among them, an alkyl group is preferred. Among them, R 1 is more preferably a propyl group or an isopropyl group.

[0059] As described above, the polyvinyl butyral resin of this embodiment is a resin using polyvinyl alcohol and an aldehyde compound as reaction raw materials. At that time, when the aldehyde compound is represented as R 1 -C(=O)H, R 1 in the general formula (iii-1) is a hydrocarbon group derived from the aldehyde compound used when synthesizing the polyvinyl butyral resin. The preferred polyvinyl butyral resin of this embodiment is preferably a resin having a partial structure represented by the above general formula (iii-1), a partial structure represented by the following general formula (iii-2), and a partial structure represented by the following general formula (iii-2).

[0060]

Chemical formula

[0061] (In the above general formula (iii-2), n3 are each independently an integer of 1 or more, and R 2 represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.)

[0062]

Chemical formula

[0063] (In the above general formula (iii-3), n4 are each independently an integer of 1 or more.)

[0064] In the above general formula (iii-2), R 2 preferably represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms. In addition, the R2 Examples thereof include a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, or a tert-butyl group, with a hydrogen atom, a methyl group, or an ethyl group being more preferred.

[0065] When the polyvinyl butyral resin of the present embodiment is represented by a resin having a partial structure represented by the general formula (iii-1), a partial structure represented by the following general formula (iii-2), and a partial structure represented by the following general formula (iii-3), the content of the partial structure represented by the general formula (iii-2) with respect to the total amount of the polyvinyl butyral resin is preferably 12% by mass or less, more preferably 8% by mass or less, and still more preferably 5% by mass or less. By setting the content of the partial structure represented by the general formula (iii-2) of the polyvinyl butyral resin within the above range, an ink layer excellent in the balance between fluidity and dispersibility can be obtained.

[0066] The weight average molecular weight of the polyvinyl butyral resin of the present embodiment is preferably from 5,000 to 150,000, more preferably from 6,000 to 100,000, and still more preferably from 7,000 to 50,000. By setting the weight average molecular weight of the polyvinyl butyral resin within the above range, excellent curability can be achieved, and both the strength and appropriate flexibility of the coating film can be achieved. In addition, a polyvinyl butyral resin having a weight average molecular weight of 5,000 to 150,000 is easily available, and by using such a polyvinyl butyral resin, an ink layer excellent in the balance between fluidity and dispersibility can be obtained.

[0067] The glass transition temperature (hereinafter sometimes referred to as Tg) of the polyvinyl butyral resin of the present embodiment is preferably in the range of 50°C to 120°C, more preferably in the range of 55°C to 115°C, and still more preferably in the range of 60°C to 110°C. In the present invention, the glass transition temperature is obtained by measurement using a differential scanning calorimeter.

[0068] The hydroxyl value of the polyvinyl butyral resin of this embodiment is preferably in the range of 10 to 40 mass%, more preferably 15 mass% to 30 mass%. By setting the amount of hydroxyl groups in the polyvinyl butyral resin within the above range, an ink layer excellent in the balance between fluidity and dispersibility can be obtained. Note that the amount of hydroxyl groups refers to the content of the partial structure represented by the above general formula (iii-3) with respect to the total amount of the polyvinyl butyral resin.

[0069] The amount of acetyl groups in the polyvinyl butyral resin is preferably 8 mass% or less, more preferably 5 mass% or less. By setting the amount of acetyl groups in the polyvinyl butyral resin within the above range, an ink layer excellent in the balance between fluidity and dispersibility can be obtained. Note that the amount of acetyl groups refers to the partial structure in the partial structure represented by the above general formula (iii-2) where R 2 is a methyl group as an acetyl group, and the amount of the acetyl group refers to the content with respect to the total amount of the polyvinyl butyral resin.

[0070] The content (solid content) of the polyvinyl butyral resin is preferably contained in an amount of 0.1 to 5 mass% with respect to the total resin solid content (100 mass%) of the ink composition, more preferably 0.1 to 4.0 mass%, and most preferably 0.2 to 3.0 mass%. By adding 0.1 mass% or more of the total amount of the polyvinyl butyral resin, the adhesion and transfer properties of the ink film tend to be maintained, and by setting the total amount to 5 mass% or less, the lamination strength of the ink can be maintained. Further, the lower limit of the solid content mass ratio in the ink composition is preferably 0.1 mass% or more, more preferably 0.2 mass% or more, and most preferably 0.3 mass%. Also, the upper limit of the solid content mass ratio in the ink is preferably 45 mass% or less, more preferably 40 mass%, still more preferably 30 mass%, even more preferably 20 mass%, even more preferably 15 mass%, and particularly preferably 10 mass%.

[0071] <Cellulose-based resin> Examples of the cellulose resin include cellulose ester resins such as cellulose acetate propionate, cellulose acetate butyrate, and other cellulose ester resins; nitrocellulose (also referred to as nitrated cotton); hydroxyalkyl cellulose; and carboxyalkyl cellulose. The cellulose ester resin preferably has an alkyl group, and examples of the alkyl group include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, a pentyl group, a hexyl group, etc., and the alkyl group may further have a substituent.

[0072] Among the above, cellulose acetate propionate, cellulose acetate butyrate, and nitrocellulose are preferable as the cellulose resin, and cellulose acetate propionate and cellulose acetate butyrate are particularly preferable. As the molecular weight, those having a weight average molecular weight of 5,000 to 200,000 are preferable, and 10,000 to 50,000 are more preferable. Also, those having a glass transition temperature of 120°C to 180°C are more preferable. When used in combination with the polyurethane resin of the present invention, it can be expected to improve blocking resistance, scratch resistance, and other ink film physical properties.

[0073] Nitrocellulose (nitrated cotton) is preferably obtained by reacting natural cellulose with nitric acid to substitute three hydroxyl groups in the six-membered ring of the anhydroglucopyranose group in natural cellulose with nitrate groups to obtain a nitrate ester.

[0074] The content (solid content) of the cellulose resin is preferably 0.1 to 5% by mass, more preferably 0.1 to 4.0% by mass, and most preferably 0.2 to 3.0% by mass with respect to the total resin solid content (100% by mass) of the ink composition. By setting the content range of the cellulose resin to 0.2 to 3.0% by mass, the effect of blocking resistance can be exhibited.

[0075] <Vinyl chloride-vinyl acetate copolymer resin> The above vinyl chloride-vinyl acetate copolymer resin is a copolymer of a vinyl chloride monomer and a vinyl acetate monomer. Therefore, the vinyl chloride-vinyl acetate copolymer resin contains vinyl chloride monomer units and vinyl acetate monomer units. Further, the vinyl chloride-vinyl acetate copolymer resin may optionally contain monomer units (other monomers) other than vinyl chloride monomer units and vinyl acetate monomer units. The other monomers are not particularly limited as long as they are copolymerizable with vinyl chloride and vinyl acetate.

[0076] As the vinyl chloride-vinyl acetate copolymer resin, the hydroxyl value is preferably 50 to 200 mgKOH / g. Further, the content of the vinyl chloride monomer units is preferably 70% by mass to 98% by mass, more preferably 80% by mass to 95% by mass, based on the total amount of the vinyl chloride-vinyl acetate copolymer resin. When the content of the vinyl chloride monomer units is within the above range, better blocking resistance can be exhibited.

[0077] The content of the vinyl acetate monomer units is preferably 2% by mass to 30% by mass, more preferably 5% by mass to 20% by mass, based on the total amount of the vinyl chloride-vinyl acetate copolymer resin. When the content of the vinyl acetate monomer units is within the above range, it is flexible and has excellent adhesion.

[0078] The mass ratio (polyurethane resin component: vinyl chloride-vinyl acetate copolymer resin) in terms of solid content between the whole polyurethane resin component and the vinyl chloride-vinyl acetate copolymer resin in the ink composition for lamination for flexible packaging of the present embodiment is preferably 60:40 to 100:0, more preferably 70:30 to 100:0. By containing the vinyl chloride-vinyl acetate copolymer resin, the lamination suitability and the pigment dispersibility can be improved. On the other hand, from the viewpoint of reducing the environmental load, it is preferable not to contain the vinyl chloride-vinyl acetate copolymer resin or to have a lower content.

[0079] Examples of the resin optionally used in combination with the liquid ink composition of the present invention include the polyurethane resin, polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2), and resins other than the resin (EF) having a Tg of 40 degrees or higher. For example, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, polyamide resin, acrylic resin, polyester resin, alkyd resin, polyvinyl chloride resin, rosin-based resin, rosin-modified maleic acid resin, ketone resin, cyclized rubber, chlorinated rubber, butyral, petroleum resin, etc. can be mentioned. The combined resin can be used alone or in a mixture of two or more. The content of the combined resin is preferably 0.1 to 25% by mass, more preferably 2 to 15% by mass, based on the total mass of the ink.

[0080] The liquid ink composition of the present invention can be used as a varnish if no colorant is added, while it can be used as a process color liquid ink or a special color liquid ink if a colorant is added. Examples of the colorant include organic and inorganic pigments and dyes used in general inks, paints, and recording agents. Examples of the organic pigment include azo-based, phthalocyanine-based, anthraquinone-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindolinone-based, quinophthalone-based, azomethine azo-based, diketopyrrolopyrrole-based, isoindoline-based pigments, etc. For blue ink, copper phthalocyanine is preferably used, and for transparent yellow ink, C.I.Pigment No Yellow83 is preferably used from the viewpoints of cost and lightfastness.

[0081] Examples of inorganic pigments include carbon black, titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, red iron oxide, aluminum, mica, etc. Additionally, a lustrous pigment (Meta Shine; Nippon Sheet Glass Co., Ltd.) in which a metal or metal oxide is coated on a glass flake or massive flake as a base material can be used. From the viewpoints of cost and coloring power, it is preferable to use titanium oxide for white ink, carbon black for black ink, aluminum for gold and silver inks, and mica for pearl ink. Aluminum is in powder or paste form, but it is preferably used in paste form from the viewpoints of handleability and safety, and whether to use leafing or non-leafing is appropriately selected from the viewpoints of brightness and density.

[0082] The colorant is preferably contained in an amount sufficient to ensure the density and coloring power of the ink, that is, at a ratio of 1 to 50% by mass based on the total mass of the ink. The colorant can be used alone or in combination of two or more.

[0083] In the present invention, optionally, a resin, extender pigment, pigment dispersant, leveling agent, defoaming agent, wax, plasticizer, infrared absorber, ultraviolet absorber, fragrance, flame retardant, etc. can also be included.

[0084] In order to stably disperse the pigment in the organic solvent, it can be dispersed with the resin alone, but a dispersant can also be used in combination to more stably disperse the pigment. As the dispersant, surfactants such as anionic, nonionic, cationic, and zwitterionic surfactants can be used. For example, a comb-shaped polymer compound obtained by adding polyester to polyethyleneimine, or an alkylamine derivative of an α-olefin maleic acid polymer, etc. can be mentioned. Specifically, Solsperse series (ZENECA), Ajisper series (Ajinomoto), Homogenol series (Kao), etc. can be mentioned. Also, BYK series (BYK Chemie), EFKA series (EFKA), etc. can be appropriately used. The dispersant is preferably contained in the ink in an amount of 0.05% by mass or more based on the total mass of the ink from the viewpoint of storage stability of the ink, and 5% by mass or less from the viewpoint of lamination suitability. More preferably, it is in the range of 0.1 - 2% by mass.

[0085] The liquid ink composition of the present invention can be produced by dissolving and / or dispersing a resin, a colorant, etc. in an organic solvent. Specifically, a pigment dispersion in which a pigment is dispersed in an organic solvent with a polyurethane resin is produced, and the obtained pigment dispersion is blended with other compounds, etc. as necessary to produce the ink.

[0086] The particle size distribution of the pigment in the pigment dispersion can be adjusted by appropriately adjusting the size of the grinding media of the dispersing machine, the filling rate of the grinding media, the dispersion treatment time, the discharge rate of the pigment dispersion, the viscosity of the pigment dispersion, etc. As the dispersing machine, generally used ones such as a roller mill, a ball mill, a pebble mill, an attritor, a sand mill, etc. can be used.

[0087] When the ink contains air bubbles or unexpectedly large particles, etc., it is preferable to remove them by filtration, etc. in order to reduce the print quality. A conventionally known filter can be used.

[0088] The ink viscosity produced by the above method is preferably in the range of 10 mPa·s or more from the viewpoint of preventing pigment sedimentation and achieving appropriate dispersion, and 1000 mPa·s or less from the viewpoint of work efficiency during ink production and printing. The above viscosity is the viscosity measured at 25°C using a B-type viscometer manufactured by Tokimec Co., Ltd.

[0089] The viscosity of the ink can be adjusted by appropriately selecting the types and amounts of raw materials used, such as polyurethane resin, colorant, organic solvent, etc. Also, the viscosity of the ink can be adjusted by controlling the particle size and particle size distribution of the pigment in the ink.

[0090] When using a colorant in the liquid ink composition of the present invention, as the hue, there are 5 process basic colors: yellow, red, blue, black, and white according to the type of colorant used, and 3 process gamut outside colors: red (orange), grass (green), and purple. Furthermore, transparent yellow, peony, vermilion, tea, gold, silver, pearl, and a nearly transparent medium for adjusting color density (including extender pigment as required) are prepared as base colors. The ink for retort pouch is appropriately selected considering the migration property and heat resistance of the pigment. The base ink of each hue is diluted with a diluting solvent to a viscosity and concentration suitable for gravure printing or flexographic printing, and is supplied to each printing unit alone or in combination.

[0091] (Printed matter) The liquid ink composition of this embodiment can be printed on a base material described later to obtain a printed matter.

[0092] As the printing method, printing can be performed using a known printing method such as gravure printing or flexographic printing, but it is particularly preferable to perform printing by the gravure printing method. Cylinders used for gravure printing can be known ones such as engraving type and etching type.

[0093] The layer formed by the liquid ink composition of the present embodiment to form a desired pattern is referred to as a printing layer. The printing layer may be a single layer or there may be a plurality of printing layers. When there are a plurality of printing layers, the ink compositions used for each printing layer may be the same, or may have the same composition except for the pigments being different, or may have different compositions.

[0094] As an example of the case where there are a plurality of such printing layers, a printed matter having, in this order, a first printing layer formed of a colored color ink composition, a second white printing layer formed of white ink, and a third white printing layer can be used. The first printing layer can form a pattern with pigments, and the second white printing layer and the third printing layer formed of the white liquid ink can be used as the background of the pattern. When the second or third printing layer is an overprint nip, it may not contain a coloring agent such as a pigment.

[0095] The base ink is diluted with a diluting solvent to a viscosity and concentration suitable for gravure printing or flexographic printing, and is supplied to each printing unit alone or in a mixture and is used for printing.

[0096] (Laminate) The present disclosure can be a laminate having a base material and a printing layer in which a liquid ink composition is printed on at least a part of the surface of the base material. Note that for the printing layer on the surface of the base material, it is sufficient that the surface of the base material and the printing layer are in direct or indirect contact.

[0097] Preferred configurations of the laminate of the present embodiment include, for example, the following (1) to (4). (1) Base material / Adhesive layer / Printing layer / Base material (2) Base material / Adhesive layer / Base material / Printing layer / Adhesive layer / Base material (3) Base material / Adhesive layer / First printing layer / Second printing layer / Base material (4) Base material / Adhesive layer / Barrier layer / Printing layer / Adhesive layer / Base material (5) Base material / Printing layer / Adhesive layer / Base material However, the laminate of the present embodiment is not limited to the above (1) to (4), and may further include an additional base material. When a plurality of base materials are included, the base materials may be the same or different. Further, the base material may be a sealable sealant film or a base material such as a multilayer film including a sealant layer formed by a heat sealant or the like, and the sealable layer is referred to as a sealant layer.

[0098] Also, the plurality of adhesive layers may have the same composition or different compositions. Further, in order to improve the adhesive strength of the adhesive layer, an anchor coat layer may be interposed therebetween.

[0099] (Base material) As the base material for printing the liquid ink composition of the present embodiment, it is useful for various films ranging from general-purpose plastic films to various high-functional films. The plastic films that can be used are not particularly limited. For example, polyamide resins such as Ny6, nylon 66, and nylon 46, polyester resins such as polyethylene terephthalate (PET), polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, and polybutylene naphthalate, polyhydroxycarboxylic acids such as polylactic acid, biodegradable resins typified by aliphatic polyester resins such as poly(ethylene succinate) and poly(butylene succinate), polyolefin resins such as polypropylene (PP) and polyethylene, films made of thermoplastic resins such as polyimide resins, polyarylate resins, or mixtures thereof, various high-functional films coated with inorganic or organic barrier coating materials on the surface, and laminates thereof can be mentioned. Among them, films made of polyester, polyamide, polyethylene, and polypropylene can be preferably used.

[0100] These films may be either unstretched films or stretched films, and their manufacturing methods are not limited either. They may be multilayer films produced by co-extruding the resins of each layer, or may be multilayer sealant films having a sealant layer on the outermost layer of the multilayer film. Also, the thickness of the base film is not particularly limited, but usually it may be in the range of 1 to 500 μm.

[0101] The above-mentioned base material may be formed of biomass polyolefin. The biomass polyolefin refers to a polyolefin resin using plant-derived olefins as raw material monomers. The raw material monomers may contain petroleum-derived monomers and do not have to contain 100% plant-derived monomers. As the biomass polyolefin, commercially available products can also be used. Examples of commercially available products include those manufactured by Braskem, SGM9450F, SLL118, SLL118 / 21, SLL218, SLL318, SLH118, SLH218, SLH0820, etc.

[0102] Also, as the base material used in the laminate of this embodiment, a base material provided with a vapor deposition layer made of an inorganic substance and / or inorganic oxide on the above-mentioned resin film may be used. By using the base material provided with the vapor deposition layer, barrier properties can be imparted to the laminate of this embodiment.

[0103] The vapor deposition layer can be formed by a known method using a known inorganic substance or inorganic oxide, and its composition and formation method are not particularly limited. Also, the laminate may have two or more vapor deposition films, and they may have the same composition or different compositions.

[0104] As the vapor deposition layer, for example, a vapor deposition film of an inorganic substance or inorganic oxide such as silicon (Si), aluminum (Al), magnesium (Mg), calcium (Ca), potassium (K), tin (Sn), sodium (Na), boron (B), titanium (Ti), lead (Pb), zirconium (Zr), yttrium (Y), etc. can be used. Further, a vapor deposition film of an inorganic oxide such as silicon oxide and aluminum oxide has transparency.

[0105] The above inorganic oxides are represented as MOx (wherein M represents an inorganic element), such as SiOx, AlOx, etc. The value of x can be in the range of 0 to 2 for silicon (Si), 0 to 1.5 for aluminum (Al), 0 to 1 for magnesium (Mg), 0 to 1 for calcium (Ca), 0 to 0.5 for potassium (K), 0 to 2 for tin (Sn), 0 to 0.5 for sodium (Na), 0 to 1.5 for boron (B), 0 to 2 for titanium (Ti), 0 to 1 for lead (Pb), 0 to 2 for zirconium (Zr), and 0 to 1.5 for yttrium (Y).

[0106] In the above, when x = 0, it is a complete inorganic single substance (pure substance) and is not transparent. When the value of x is the upper limit of the range, it indicates that it is completely oxidized.

[0107] As the vapor deposition layer, silicon (Si) or aluminum (Al) is preferably used. For silicon (Si), those with a value of x in the range of 1.0 to 2.0, and for aluminum (Al), those with a value of x in the range of 0.5 to 1.5 can be used.

[0108] The above vapor deposition layer can be formed on the surface of the above substrate or the like by methods such as physical vapor deposition methods (Physical Vapor Deposition method, PVD method) such as vacuum vapor deposition method, sputtering method, and ion plating method, chemical vapor deposition methods (Chemical Vapor Deposition method, CVD method) such as plasma chemical vapor deposition method, thermal chemical vapor deposition method, and photo chemical vapor deposition method.

[0109] The thickness of the vapor deposition layer of the above vapor deposition layer is not particularly limited as long as a certain gas barrier function can be exhibited even when the vapor deposition layer is alone. The preferable range of the thickness varies depending on the type of the metal or metal oxide to be vapor deposited, but 0.05 to 70 nm is preferable, 0.1 to 70 nm is more preferable, 3 to 70 nm is more preferable, and 5 to 60 nm is even more preferable.

[0110] As the above metal vapor deposition film, a VM-CPP film obtained by vapor depositing a metal such as aluminum on a CPP film, or a VM-OPP film obtained by vapor depositing a metal such as aluminum on an OPP film can be used. Further, examples of the above transparent vapor deposition film include films obtained by vapor depositing silica or alumina on an OPP film, a PET film, a nylon film, etc. A film having a coating applied on the vapor deposition layer may be used for the purpose of protecting an inorganic vapor deposition layer of silica or alumina.

[0111] <Laminating method> The laminating method for producing the laminate of the present embodiment is not particularly limited, and examples thereof include methods such as dry lamination, wet lamination, non-solvent lamination, and extrusion lamination. At this time, the layer located between the base materials is referred to as an adhesive layer.

[0112] Examples of the adhesive used in the above dry lamination include solvent-based two-component curable adhesives. The "solvent-based" adhesive refers to a form used in the so-called dry lamination method, in which after the adhesive is applied to a base material, it is heated in an oven or the like to volatilize the organic solvent in the coating film and then laminated with another base material, and includes a polyisocyanate composition, a polyol composition, and an organic solvent capable of dissolving (diluting) them.

[0113] In the above two-component curable adhesive, in consideration of the construction of a sustainable recycling-oriented society that should continue to develop (sustainability), it is preferable to use plant-derived raw materials (biomass raw materials) as raw materials for the above polyisocyanate composition or polyol composition.

[0114] By appropriately using biomass raw materials, the environmental load can be reduced. Examples of biomass raw materials include castor oil, dehydrated castor oil, hydrogenated castor oil which is a hydrogenated product of castor oil, castor oil-based polyols such as 5 - 50 mol adducts of alkylene oxide with castor oil, aliphatic polybasic acids such as succinic acid, succinic anhydride, glutaric acid, adipic acid, azelaic acid, sebacic acid, itaconic acid, and alkyl esterified products of such acids, dimer acid, and the like.

[0115] As the above-mentioned adhesive using biomass raw materials, commercially available products can also be used. As commercially available products, adhesives described in the Japan Organic Resources Association can be used. For example, Dick Dry BM (manufactured by DIC Corporation), Take Nate BM (Mitsui Chemicals, Inc.), and the like can be mentioned.

[0116] The weight of the above-mentioned adhesive layer after drying is preferably 0.1 - 10 g / m 2 and more preferably 1 - 6 g / m 2 and even more preferably 2 - 5 g / m 2 In addition, the thickness of the adhesive layer is preferably 0.1 - 10 μm, more preferably 1 - 7 μm, and even more preferably 2 - 5 μm.

[0117] Also, various adhesives can be used as the above-mentioned adhesive layer, but it is preferable to use a pressure-sensitive adhesive.

[0118] Examples of the pressure-sensitive adhesive include rubber-based adhesives obtained by dissolving polyisobutylene rubber, butyl rubber, or mixtures thereof in organic solvents such as benzene, toluene, xylene, and hexane, or those obtained by blending tackifiers such as abietic acid rosin ester, terpene-phenol copolymer, terpene-indene copolymer, etc. with these rubber-based adhesives, or acrylic adhesives obtained by dissolving acrylic copolymers having a glass transition point of 20°C or lower, such as 2-ethylhexyl acrylate - n-butyl acrylate copolymer, 2-ethylhexyl acrylate - ethyl acrylate - methyl methacrylate copolymer, etc. in organic solvents.

[0119] When a material having gas barrier properties is used as the above-mentioned adhesive or the anchor coat agent described later, a laminate film having particularly excellent barrier properties can be obtained.

[0120] Particularly preferably, as an adhesive having excellent gas barrier properties, the oxygen barrier property of the cured coating film of the adhesive applied at 3 g / m 2 (solid content) is 300 cc / m 2 / day / atm or less, or the water vapor barrier property is 120 g / m 2 / day or less, and those satisfying at least one of the conditions are referred to. Commercially available products include the "PASLIM" series such as PASLIM VM001 and PASLIM J350X manufactured by DIC Corporation, and "Maxieve" manufactured by Mitsubishi Gas Chemical Company.

[0121] In addition, the above adhesive layer can also be formed of a thermoplastic resin, and the forming method can be a conventionally known method, for example, a melt extrusion lamination method or a sand lamination method. The liquid ink composition of the present invention is particularly preferably laminated by an extrusion lamination method or a sand lamination method in order to improve the interlayer adhesion strength of the extrusion lamination.

[0122] Examples of the thermoplastic resin that can be used for the adhesive layer include polyethylene resins such as low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), medium-density polyethylene (MDPE), and high-density polyethylene (HDPE); polypropylene resins such as homopolymers of propylene, random copolymers of propylene-α-olefin, and block copolymers of propylene-α-olefin; norbornene-based polymers such as ring-opening polymers (COP) of norbornene-based monomers and norbornene-based copolymers (COC) obtained by copolymerizing norbornene-based monomers with olefins such as ethylene, and hydrogenated products thereof; cyclic polyolefin resins such as vinyl alicyclic hydrocarbon polymers and cyclic conjugated diene polymers; polyethylene-based elastomers such as ethylene-vinyl acetate copolymers (EVA) and ethylene-α-olefin copolymers; and thermoplastic elastomers such as polypropylene-based elastomers and butene-based elastomers; ethylene-based copolymers such as ethylene-methyl methacrylate copolymers (EMMA), ethylene-ethyl acrylate copolymers (EEA), ethylene-methyl acrylate (EMA) copolymers, ethylene-ethyl acrylate-maleic anhydride copolymers (E-EA-MAH), ethylene-acrylic acid copolymers (EAA), and ethylene-methacrylic acid copolymers (EMAA); and ionomers of ethylene-acrylic acid copolymers and ionomers of ethylene-methacrylic acid copolymers. Further, in order to improve the adhesion between layers, acid-modified polyolefin resins obtained by modifying the above polyolefin resins with unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, and itaconic acid can also be used.

[0123] In addition, resins obtained by graft-polymerizing or copolymerizing unsaturated carboxylic acids, unsaturated carboxylic acid anhydrides, and ester monomers onto polyolefin resins can also be used.

[0124] These resins can be used alone or in combination of two or more.

[0125] In addition, as the polyethylene resin, it is also preferable to use a resin using ethylene derived from biomass as a monomer unit.

[0126] When laminating the adhesive layer by the extrusion lamination method, an anchor coat layer formed by applying an anchor coat agent to the surface of the layer to be laminated and drying it may be provided.

[0127] Examples of the anchor coat agent include any resin having a heat resistance temperature of 135°C or higher, such as an anchor coat agent composed of a polybutadiene resin, a urethane resin, a polyisocyanate-polyether polyol, a polyethyleneimine, a vinyl-modified resin, an epoxy resin, a polyester resin, an alkyl titanate, etc., and an anchor coat agent obtained by diluting the above adhesive with an organic solvent. Among them, a polyethyleneimine-based anchor coat agent and an anchor coat agent obtained by diluting the above adhesive with an organic solvent can be preferably used. Further, a silane coupling agent may be used in combination as an additive, and nitrocellulose may be used in combination to enhance heat resistance.

[0128] (Packaging material) The packaging material of this embodiment preferably includes a laminate laminate including a printing layer formed from the above liquid ink composition, and more preferably is composed of a laminate laminate including the ink composition. For example, it may be a packaging material in which two laminate laminates are arranged and sealed so that their respective sealant layers are in contact with each other, or a packaging material in which a continuous (single) laminate laminate is folded and arranged so that the sealant layers are in contact with each other and sealed, or a packaging material in which the laminate laminate and a thermoplastic resin film are arranged and sealed so that the sealant layer of the laminate laminate is in contact with the thermoplastic resin film. The sealing method is not particularly limited, and it may be heat sealing or ultrasonic sealing, and a known method can be adopted.

[0129] The packaging material can be suitably used as a package. Examples of the package include food packages such as Western confectionery, snacks, bread, Japanese confectionery, and seasonings; medical packages such as drugs, bandages, and syringes; and hygiene product packages such as cleaning cloths, masks, and brushes.

[0130] The printed matter, laminate, and packaging material of the present invention are recyclable, and the plastic after recycling can be used as recycled plastic.

[0131] (Recycled plastic) The printed matter, laminate, and packaging material of the present invention can also be directly processed by various known recycled plastic processing methods to produce recycled plastic. Since the printed matter, laminate, and packaging material of the present invention have a configuration with a reduced chlorine content in the laser printing layer, they are optimal for recycling as recycled plastic. As an example of a specific embodiment, a manufacturing method having a step of separating the laminate of the present invention into each base material, or a step of crushing the laminate or packaging material of the present invention, a step of melt-kneading the crushed film pieces, and a step of pelletizing the melt-kneaded kneaded product can be used to obtain recycled plastic.

[0132] The crusher used during crushing (pulverization) may be a known crusher and is not particularly limited.

[0133] The film pieces after pulverization are physically blended by melt-kneading, solvent casting blend, latex blend, polymer complex, etc. In particular, the melt-kneading method is common. Examples of the apparatus for kneading include a tumbler, Henschel mixer, rotary mixer, super mixer, ribbon tumbler, V blender, etc. After melt-kneading with such a kneading apparatus, it is pelletized. For melt-kneading pelletization, it is common to use a single-screw or multi-screw extruder. It may be fed as it is in the form of film pieces, or may be fed after compression and volume reduction treatment with or without heating. Further, in addition to these extruders, a Banbury mixer, roller, co-kneader, blast mill, Brabender Plastograph, etc. can also be used, and these are operated batchwise or continuously. Also, instead of melt-kneading, it may be used as a molding resin and melt-kneaded in the heating cylinder of a molding machine.

[0134] As the plastic film that can be used, a polyester resin film is particularly preferable. On the other hand, the liquid ink composition of the present invention is particularly useful for a polypropylene film that is likely to have reduced adhesion, and can also be widely used for various high-functional films in which inorganic or organic barrier coating materials are applied to the surfaces of other polypropylene, nylon, polyethylene resin films, etc.

Examples

[0135] The present invention will be described more specifically with reference to examples. Hereinafter, both "parts" and "%" are based on mass.

[0136] In addition, the measurement of the weight average molecular weight (polystyrene conversion) by GPC (gel permeation chromatography) in the present invention was carried out under the following conditions using an HLC8220 system manufactured by Tosoh Corporation. Separation column: TSKgel GMH manufactured by Tosoh Corporation HR -N, 4 were used. Column temperature: 40 °C. Mobile phase: Tetrahydrofuran manufactured by Wako Pure Chemical Industries, Ltd. Flow rate: 1.0 ml / min. Sample concentration: 1.0 wt%. Sample injection volume: 100 microliters. Detector: Differential refractometer. The viscosity was measured at 25°C using a B-type viscometer manufactured by Tokimec Co., Ltd.

[0137] [Synthesis Example 1] Into a four-necked flask equipped with a stirrer, thermometer, reflux condenser, and nitrogen gas inlet tube, 80 parts of neopentyl glycol adipate diol (hydroxyl value: 56.6 mg KOH / g), 20 parts of polyethylene glycol (hydroxyl value: 111 mg KOH / g), and 22.54 parts of isophorone diisocyanate were charged and reacted at 90°C for 10 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group content of 2.84% by weight. Then, 66.0 parts of ethyl acetate was added thereto to obtain a homogeneous solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 7.25 parts of isophorone diamine, 0.27 part of di-n-butylamine, 131.3 parts of ethyl acetate, and 106.2 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45°C for 5 hours to obtain a polyurethane resin solution D1. The obtained polyurethane resin solution D1 had a resin solid content concentration of 30.2% by weight, an Mw of the resin solid content of 50,000, and a urethane bond concentration of 0.93 mmol / g.

[0138] [Synthesis Example 2] Into a four-necked flask equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen gas inlet tube, 90 parts of neopentyl glycol adipate diol (hydroxyl value: 21.2 mg KOH / g), 10 parts of polyethylene glycol (hydroxyl value: 111 mg KOH / g), and 13.79 parts of isophorone diisocyanate were charged, and the reaction was carried out at 90 °C for 10 hours under a nitrogen stream to produce a urethane prepolymer having an isocyanate group content of 2.60% by weight. Then, 61.3 parts of ethyl acetate was added thereto to obtain a uniform solution of the urethane prepolymer. Next, the urethane prepolymer solution was added to a mixture consisting of 6.06 parts of isophorone diamine, 0.45 part of di-n-butylamine, 121.2 parts of ethyl acetate, and 98.3 parts of isopropyl alcohol, and the mixture was stirred and reacted at 45 °C for 5 hours to obtain a polyurethane resin solution D2. The obtained polyurethane resin solution D2 had a resin solid content concentration of 30.6% by weight, an Mw of the resin solid content of 70,000, and a urethane bond concentration of 0.45 mmol / g.

[0139] A vinyl chloride-vinyl acetate copolymer resin having a hydroxyl group used in combination with the polyurethane resin (resin monomer composition: vinyl chloride / vinyl acetate / vinyl alcohol = 92 / 3 / 5 by mass%, hydroxyl value (mg KOH) = 64) was made into a 15% solution with ethyl acetate to obtain a vinyl chloride-vinyl acetate copolymer resin solution.

[0140] A butyral resin, Mobital B16H (manufactured by Kuraray Co., Ltd.), used in combination with the polyurethane resin was made into a 15% solution with ethyl acetate to obtain a butyral resin solution.

[0141] [Example 1] 25 parts of polyurethane resin solution D1 (solid content 30%), 10 parts of vinyl chloride-vinyl acetate copolymer resin (solid content 15%), 35 parts of titanium oxide pigment JR-805 manufactured by Teika Co., Ltd., 10 parts of isopropyl alcohol, and 10.5 parts of ethyl acetate were kneaded using a dynomill (manufactured by Willy E. Bachofen), and 8.5 parts of a mixed solution of isopropyl alcohol:ethyl acetate = 1:1 and 1 part of polybutadiene diol (NISSO PB G-1000 manufactured by Nippon Soda Co., Ltd.) were further added to the obtained white kneaded meat base ink to prepare the liquid ink of the present invention.

[0142] [Examples 2 to 10 and Comparative Examples 1 and 2] Regarding Examples 2 to 10 shown in Tables 1 and 2 and Comparative Examples 1 and 2 shown in Table 3, white kneaded meat base ink was prepared in the same procedure as in Example 1.

[0143] Note that NISSO PB B-1000 manufactured by Nippon Soda Co., Ltd. was used as polybutadiene (A1) in the table, NISSO PB GI-1000 manufactured by Nippon Soda Co., Ltd. was used as hydrogenated polybutadiene diol (A3), and Poly ip manufactured by Idemitsu Kosan Co., Ltd. was used as polyisoprene diol (B1).

[0144] 1) Adhesion to film The viscosity of the obtained liquid white ink was adjusted to 16 seconds (25 °C) with a Zahn cup #3 (manufactured by Separation Co., Ltd.) using ethyl acetate, and printed on various films (OPP, PET, Ny) with a gravure proofing machine equipped with a gravure plate with a plate depth of 35 μm. After leaving the printed matter for 1 day, a cellophane tape (12 mm width, manufactured by Nichiban Co., Ltd.) was attached to the printed surface, and the appearance state of the printed film when this was rapidly peeled off was visually judged in the following 3 stages.

[0145] Note that P2161 (20 μm) manufactured by Toyobo Co., Ltd. was used for the OPP film, E5102 manufactured by Toyobo Co., Ltd. was used for the PET, and Emblem ON manufactured by Unitika Ltd. was used for the Ny.

[0146] ○: The printed film did not peel off at all. △: 50 to 80% of the printed film remained on the film. ×: Less than 50% of the printed film remained on the film.

[0147] 2) Extrusion lamination (PEEL) strength The viscosities of the ink compositions described in the examples and comparative examples were adjusted to 16 seconds (25 °C) with a Zahn cup #3 (manufactured by Rika Shakai) using ethyl acetate. A gravure proofing machine equipped with a gravure plate with a plate depth of 35 μm was used to produce printed matter using OPP film P2161 (20 μm) manufactured by Toyobo Co., Ltd. To this printed matter, a polyethyleneimine-based anchor coating agent was applied at 0.1 g / m 2 After coating, molten polyethylene was laminated to a thickness of 40 μm using an extrusion laminating machine. After obtaining a laminated product, the laminated film was cut into 15 mm widths, and a 90-degree peel test (measurement of PEEL strength) was conducted at a pulling speed of 50 mm / min.

[0148] ◎: The PEEL strength is 1.5 - 2.0 N / 15 mm. ○: The PEEL strength is 1.0 - 1.5 N / 15 mm. △: The PEEL strength is 0.5 - 1.0 N / 15 mm. ×: The PEEL strength is less than 0.5 / 15 mm.

[0149] 3) Dry lamination strength (Measurement of dry lamination strength (OPP film)) The viscosities of the ink compositions described in the examples and comparative examples were adjusted to 16 seconds (25 °C) with a Zahn cup #3 (manufactured by Rika Shakai) using ethyl acetate. A gravure proofing machine equipped with a gravure plate with a plate depth of 35 μm was used to print on a corona-treated polypropylene film and dry at 40 - 50 °C to obtain printed matter.

[0150] Regarding the obtained OPP printed matter, a dry laminate was performed using an ether-based dry laminate adhesive (Dick Dry LX-401A / SP-60 (manufactured by DIC)) with a dry laminator (manufactured by DIC Engineering) to laminate an unstretched polypropylene film (hereinafter, CPP: Toyobo Co., Ltd. Pyren Film-CT P1128 30 μm). After aging at 40°C for 3 days to obtain a laminate, it was cut into 15 mm widths and a 90-degree peel test was conducted at a pulling speed of 300 mm / min.

[0151] Tables 1 to 3 show the formulations of each liquid white ink and the evaluation results.

[0152]

Table 1

[0153]

Table 2

[0154]

Table 3

[0155] In the examples, all performances were good, and the adhesiveness to the OPP film was also good. In the comparative examples, it was difficult to have all of these characteristics, and the performance on the OPP film was particularly inferior.

[0156] Also, in the examples, excellent adhesion and extrusion lamination strength were achieved even in a composition that does not contain a vinyl chloride-vinyl acetate copolymer.

Industrial Applicability

[0157] The liquid ink composition of the present invention can be widely applied to industrial products such as food packaging materials, sanitary products, cosmetics, and electronic components.

Claims

1. A binder resin, at least one selected from polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2), and an organic solvent (C), wherein the polybutadiene (A1), polybutadiene diol (A2), hydrogenated polybutadiene diol (A3), polyisoprene polyol (B1), and hydrogenated polyisoprene polyol (B2) have a number average molecular weight of 500 to 50,000 and are contained in an amount of 0.05 to 10.0% by mass based on the total solid content of the liquid ink composition A liquid ink composition characterized by the above.

2. The liquid ink composition according to claim 1, containing a polyurethane resin (D) as the binder resin.

3. Furthermore, the liquid ink composition according to claim 2, containing a resin (E) having a glass transition temperature (Tg) of 40°C or higher.

4. The liquid ink composition according to claim 2, wherein the polyurethane resin (D) has a urea bond.

5. The liquid ink composition according to claim 2, wherein the polyurethane resin (D) uses a polyether resin as a reaction raw material, and the polyether resin accounts for 1 to 50% by mass based on the total amount of the polyurethane resin (D).

6. The liquid ink composition according to claim 2, wherein the urethane bond concentration of the polyurethane resin (D) is 0.3 to 2.0 mmol / g.

7. The liquid ink composition according to claim 3, wherein the resin (E) having a glass transition temperature (Tg) of 40°C or higher is at least one of a vinyl chloride-vinyl acetate copolymer resin having a hydroxyl group, a polyvinyl butyral resin, and a cellulose-based resin.

8. The liquid ink composition according to claim 1 or 2, wherein the organic solvent (C) does not contain an aromatic organic solvent and / or a ketone-based solvent.

9. A printed matter obtained by printing the liquid ink composition according to claim 1 or 2.

10. The printed matter is a printed matter obtained by printing the liquid ink composition according to claim 1 or 2 on a plastic film, and the plastic film is a polyolefin resin The printed matter according to claim 9.

11. A laminate laminate having the printed matter according to claim 9.

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