Liquid printing ink, printed matter

Abstract

To provide a liquid printing ink in which the printing ink layer itself has high printing physical properties such as scratchability, adhesion, abrasion resistance, blocking resistance, and slipperiness, and is improved with biomass raw material.SOLUTION: Provided is a liquid printing ink that contains a binder resin (A) and a wax (B), where: (1) rice bran wax (B1) and carnauba wax (B2) are contained; and (2) a total amount of rice bran wax (B1) and carnauba wax (B2) is contained by 0.5 to 10.0 mass% in a total ink solid content.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a liquid printing ink that can be used as a gravure ink or a flexographic ink for flexible packaging.

Background Art

[0002] Liquid printing inks such as gravure inks and flexographic inks are widely used for the purpose of imparting cosmetic properties and functional properties to the printing substrates of flexible packaging films. Conventionally, these liquid printing inks have been used in both cases where a laminated body obtained by laminating a printed matter and various films with an adhesive is used as a packaging material, and where the printed matter printed on the film is used as a packaging material as it is. However, in response to recent efforts towards resource conservation and simplification of packaging forms, there is an increasing demand to use the gravure / flexographic printed matter itself as a packaging material for the purpose of reducing the use of petroleum resource-derived films and simplifying post-processing. Accordingly, high printing physical properties such as scratch resistance, adhesion, abrasion resistance, blocking resistance, and slipperiness are being required for the printing ink layer itself.

[0003] Furthermore, in recent years, the biomass conversion of packaging materials has been required, and the printing inks used for packaging materials are also required to use biomass raw materials instead of 100% petroleum-derived raw materials. There is a growing movement to improve the printing physical properties themselves with biomass raw materials.

[0004] As a method for improving printing physical properties such as scratch resistance, adhesion, abrasion resistance, blocking resistance, and slipperiness required for the printing ink layer itself, a method of adding a small amount of wax such as hydrocarbon wax or fatty acid amide wax is known. For example, Patent Document 1 discloses a gravure ink containing a binder resin (A) and a hydrocarbon wax (B), wherein (1) the hardness (penetration) of the hydrocarbon wax (B) at 25°C defined by Japanese Industrial Standard JIS K 2207 is 0.5 to 12, and (2) the hydrocarbon wax (B) is contained in an amount of 0.1 to 2.5% by mass based on 100% by mass of the gravure ink. However, the hydrocarbon waxes and fatty acid amide waxes disclosed herein were not biomass raw materials.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] The problem to be solved by the present invention is to provide a liquid printing ink that has high printing physical properties such as scratch resistance, adhesion, abrasion resistance, blocking resistance, and slipperiness in the printing ink layer itself and is improved with biomass raw materials.

Means for Solving the Problems

[0007] As a result of intensive research to solve the above problems, the present inventors have found that the present invention can solve the above problems by containing a binder resin (A) and a specific wax (B) in specific amounts, and have completed the present invention.

[0008] That is, the present invention provides a liquid printing ink for printing on a paper substrate or a plastic substrate, which contains a binder resin (A) and a wax (B) and satisfies the following (1) and (2). (1) As the wax (B), it contains rice bran wax (B1) and carnauba wax (B2). (2) It contains 0.5 to 10.0% by mass in total of rice bran wax (B1) and carnauba wax (B2) based on the total solid content of the ink.

[0009] The present invention also provides a liquid printing ink for surface printing.

[0010] The present invention further provides a liquid printing ink containing olefin wax (B3).

[0011] The present invention also provides a liquid printing ink in which the mass ratio (B1) / (B2) of rice bran wax (B1) to carnauba wax (B2) is in the range of (B1) / (B2) = 1 / 10 to 2 / 1.

[0012] The present invention further provides a liquid printing ink in which glycerin acetate fatty acid ester is added in an amount of 0.8 to 12.0% by mass based on the total solid content of the ink.

[0013] The present invention also provides a liquid printing ink in which the binder resin (A) is an acrylic resin (A1), a polyurethane resin (A2), a cellulose resin (A3), a chlorinated vinyl resin (A4), or a rosin resin (A5).

[0014] The present invention also provides a printed matter printed with the liquid printing ink on a paper substrate or a plastic substrate.

[0015] The present invention also provides an integrated packaging film printed with the liquid printing ink on a heat-shrinkable plastic substrate.

[0016] The present invention also provides a printed matter printed with the liquid printing ink on a plastic substrate containing a biomass raw material.

[0017] The present invention also provides an integrated packaging film printed with the liquid printing ink on a heat-shrinkable biomass plastic substrate. [Effect of the Invention]

[0018] The liquid printing ink of the present invention has high printing physical properties such as scratch resistance, adhesion, abrasion resistance, blocking resistance, and slipperiness in the formed printing ink layer itself, and these are improved using biomass raw materials. [Embodiments for Carrying Out the Invention]

[0019] (Definition of terms) In the present invention, the liquid printing ink refers to a liquid ink applicable to a printing method using a printing plate, such as gravure ink or flexo ink, preferably gravure ink or flexo ink. Further, the liquid printing ink of the present invention does not contain an active energy curable component, that is, it is a liquid ink non-reactive to active energy rays. In the present invention, "parts" all indicate "parts by mass", "total amount of coating agent" indicates the total amount of ink including all volatile components such as organic solvents, and "total amount of solid content of coating agent" indicates the total amount of only non-volatile components without volatile components. In the present invention, the front printing ink refers to an ink used for a printed matter that circulates with the printed surface exposed after printing on a base material such as paper or film. Shrink films, films for integrated packaging, and films for bread packaging, which are specific uses of the present invention, often use such front printing ink. On the other hand, the back printing ink, also referred to as laminating ink, refers to an ink used for a printed matter that circulates with the printed surface covered with paper or film and not directly exposed after printing on a base material such as paper or film. Since it has no possibility of directly contacting food, it is often used as an ink for retort packages, etc.

[0020] First, the liquid printing ink of the present invention is a liquid printing ink for printing on a paper substrate or a plastic substrate, which contains a binder resin (A) and a wax (B), and is characterized by satisfying the following (1) and (2). (1) As the wax (B), it contains rice bran wax (B1) and carnauba wax (B2). (2) It contains 0.5 to 10.0% by mass in total of rice bran wax (B1) and carnauba wax (B2) based on the total solid content of the ink.

[0021] (Binder resin (A)) The binder resin (A) used in the present invention is not particularly limited as long as it is a binder resin used in a liquid ink applied to a printing method using a printing plate, such as gravure ink or flexo ink. However, since it is excellent in scratch resistance, adhesion, abrasion resistance, blocking resistance, slipperiness, etc. to a paper substrate or a plastic substrate, which is an object of the present invention, among others, an acrylic resin (A1), a polyurethane resin (A2), a cellulose resin (A3), a chlorinated vinyl resin (A4), or a rosin resin (A5) is preferably used as the main binder resin.

[0022] (Acrylic resin (A1)) The acrylic resin is not particularly limited as long as it is a copolymer of a polymerizable monomer mainly composed of (meth)acrylate. Examples of the polymerizable monomer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, iso-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, iso-octyl (meth)acrylate, lauryl (meth)acrylate, stearyl (meth)acrylate, iso-nonyl (meth)acrylate, cyclohexyl (meth)acrylate, benzyl (meth)acrylate, methoxyethyl (meth)acrylate, ethoxyethyl (meth)acrylate, phenoxyethyl (meth)acrylate, and the like. The polymerization method is also not particularly limited, and those obtained by known bulk polymerization, solution polymerization, emulsion polymerization, suspension polymerization methods, etc. can be used. The weight average molecular weight of the acrylic resin is preferably 5,000 to 200,000, more preferably in the range of 10,000 to 100,000. Also, the addition amount of the acrylic resin is 1.0 to 70.0% by mass based on the ink solid content, preferably 5.0 to 50.0% by mass.

[0023] (Polyurethane resin (A2)) The polyurethane resin is not particularly limited as long as it is a polyurethane resin obtained by reacting a polyol and a polyisocyanate. As the polyol, for example, various known polyols generally used in the production of polyurethane resins can be used, and one kind or two or more kinds can be used in combination. For example, saturated or unsaturated low molecular weight polyols (1) 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 glycol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerin, trimethylolpropane, trimethylolethane, 1,2,6-hexanetriol, 1,2,4-butanetriol, sorbitol, pentaerythritol, etc.; polyester polyols (2) obtained by dehydration condensation or polymerization of these low molecular weight polyols (1) and polyvalent carboxylic acids such as sebacic acid, adipic acid, phthalic acid, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, glutaric acid, pimelic acid, speric acid, azelaic acid, trimellitic acid, pyromellitic acid or anhydrides thereof; polyester polyols (3) obtained by ring-opening polymerization of cyclic ester compounds such as lactones such as polycaprolactone, polyvalerolactone, poly(β-methyl-γ-valerolactone); polycarbonate polyols (4) obtained by reaction of the above low molecular weight polyols (1) etc. with, for example, dimethyl carbonate, diphenyl carbonate, ethylene carbonate, phosgene, etc.; polybutadiene glycols (5); glycols (6) obtained by adding ethylene oxide or propylene oxide to bisphenol A; acrylic polyols (7) 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.

[0024] Examples of the polyisocyanate include various known aromatic diisocyanates, aliphatic diisocyanates, alicyclic diisocyanates, etc. generally used in the production of polyurethane resins. For example, aromatic polyisocyanates such as 1,3-phenylene diisocyanate, 1,4-phenylene diisocyanate, 1-methyl-2,4-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-2,5-phenylene diisocyanate, 1-methyl-2,6-phenylene diisocyanate, 1-methyl-3,5-phenylene diisocyanate, 1-ethyl-2,4-phenylene diisocyanate, 1-isopropyl-2,4-phenylene diisocyanate, 1,3-dimethyl-2,4-phenylene diisocyanate, 1,3-dimethyl-4,6-phenylene diisocyanate, 1,4-dimethyl-2,5-phenylene diisocyanate, diethylbenzene diisocyanate, diisopropylbenzene diisocyanate, 1-methyl-3,5-diethylbenzene diisocyanate, 3-methyl-1,5-diethylbenzene-2,4-diisocyanate, 1,3,5-triethylbenzene-2,4-diisocyanate, naphthalene-1,4-diisocyanate, naphthalene-1,5-diisocyanate, 1-methyl-naphthalene-1,5-diisocyanate, naphthalene-2,6-diisocyanate, naphthalene-2,7-diisocyanate, 1,1-dinaphthyl-2,2'-diisocyanate, biphenyl-2,4'-diisocyanate, biphenyl-4,4'-diisocyanate, 3-3'-dimethylbiphenyl-4,4'-diisocyanate, 4,4'-diphenylmethane diisocyanate, 2,2'-diphenylmethane diisocyanate, diphenylmethane-2,4-diisocyanate;Aliphatic or alicyclic polyisocyanates such as tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, trimethylhexamethylene diisocyanate, 1,3-cyclopentylene diisocyanate, 1,3-cyclohexylene diisocyanate, 1,4-cyclohexylene diisocyanate, 1,3-di(isocyanatomethyl)cyclohexane, 1,4-di(isocyanatomethyl)cyclohexane, lysine diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate, 2,4'-dicyclohexylmethane diisocyanate, 2,2'-dicyclohexylmethane diisocyanate, 3,3'-dimethyl-4,4'-dicyclohexylmethane diisocyanate, etc. can be used. These polyisocyanates may be used alone or in combination of two or more. Among these, these diisocyanate compounds can be used alone or in a mixture of two or more.;

[0025] A chain extender can also be used. Examples of the chain extender include ethylenediamine, propylenediamine, hexamethylenediamine, diethylenetriamine, triethylenetetramine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, etc. In addition, amines having a hydroxyl group in the molecule such as 2-hydroxyethyl ethylenediamine, 2-hydroxyethyl propylenediamine, 2-hydroxyethyl propylenediamine, di-2-hydroxyethyl ethylenediamine, di-2-hydroxyethylenediamine, di-2-hydroxyethyl propylenediamine, 2-hydroxypyrropyl ethylenediamine, di-2-hydroxypyrropyl ethylenediamine, di-2-hydroxypropyl ethylenediamine can also be used. These chain extenders can be used alone or in a mixture of two or more.

[0026] Moreover, a monohydric active hydrogen compound can also be used as a terminal blocking agent for the purpose of terminating the reaction. Examples of such compounds include dialkylamines such as di-n-butylamine, and alcohols such as ethanol and isopropyl alcohol. Further, when it is particularly desired to introduce a carboxyl group into the polyurethane resin, amino acids such as glycine and L-alanine can be used as the reaction terminating agent. These terminal blocking agents can be used alone or in combination of two or more. The weight average molecular weight of the polyurethane resin is preferably from 10,000 to 100,000, more preferably in the range of 15,000 to 80,000. Also, the addition amount of the polyurethane resin is preferably 1.0 to 60.0% by mass, more preferably 5.0 to 40.0% by mass, based on the ink solid content.

[0027] (Cellulosic resin (A3)) Examples of the cellulosic resin include 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, and a hexyl group. Further, the alkyl group may have a substituent. Among the above, cellulose acetate propionate, cellulose acetate butyrate, and nitrocellulose are preferred as the cellulosic resin. Particularly preferred are cellulose acetate propionate and cellulose acetate butyrate. The molecular weight is preferably a weight average molecular weight of 5,000 to 200,000, more preferably 10,000 to 50,000. Also, those having a glass transition temperature of 120°C to 180°C are preferred. When used in combination with the polyurethane resin (A2) of the present invention, improvement in blocking resistance, scratch resistance and other ink film physical properties can be expected. Nitrocellulose 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 form a nitrate ester.

[0028] By using nitrocellulose, high dispersibility in pigments can be obtained. Therefore, when it is particularly used as a coating agent for surface printing, it can improve the strength of the printed ink film and is suitable. As the nitrocellulose, a nitrogen content of 10 to 13% by mass and an average degree of polymerization of 30 to 500 are preferable, and more preferably, the nitrogen content is 10 to 13% by mass and the average degree of polymerization is 45 to 290.

[0029] The addition amount of cellulose acetate propionate or cellulose acetate butyrate is 1.0 to 40.0% by mass in the ink solid content, preferably 3.0 to 20.0% by mass. On the other hand, nitrocellulose can also be used as a biomass raw material.

[0030] (Chlorinated vinyl resin (A4)) In the chlorinated vinyl resin, the vinyl resin may be a homopolymer or copolymer of a compound having a vinyl group. Representative homopolymers or copolymers include homopolymers or copolymers using vinyl chloride or vinyl acetate. Examples of vinyl chloride resins include polyvinyl chloride, chlorinated polyvinyl chloride, polyvinylidene chloride, chlorinated polyethylene, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl isobutyl ether copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-propylene copolymer, vinyl chloride-styrene copolymer, vinyl chloride-isobutylene copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-styrene-maleic anhydride terpolymer, vinyl chloride-styrene-acrylonitrile copolymer, vinyl chloride-butadiene copolymer, vinyl chloride-isoprene copolymer, vinyl chloride-chlorinated propylene copolymer, vinyl chloride-vinylidene chloride-vinyl acetate terpolymer, vinyl chloride-maleic acid ester copolymer, vinyl chloride-methacrylic acid ester copolymer, vinyl chloride-acrylonitrile copolymer, vinyl chloride-various vinyl ether copolymers, and other vinyl chloride resins, as well as blends thereof with each other or blends with other synthetic resins not containing chlorine, such as acrylonitrile-styrene copolymer, acrylonitrile-butadiene-styrene copolymer, ethylene-vinyl acetate copolymer, ethylene-ethyl (meth)acrylate copolymer, polyester, etc., block copolymers, graft copolymers, etc. These vinyl chloride resins may be a mixture of two or more kinds, or a mixture with other synthetic resins. Among these, vinyl chloride-vinyl acetate copolymer is particularly preferred.

[0031] The vinyl chloride-vinyl acetate copolymer can be a known one without particular limitation, but among them, a vinyl chloride-vinyl acetate copolymer having a hydroxyl group is preferably used, and a vinyl chloride-vinyl acetate copolymer having a hydroxyl group with a hydroxyl value of 50 to 200 mgKOH / g and a content ratio of the vinyl chloride component in the copolymer of 80 to 95% by weight is still more preferred.

[0032] The vinyl chloride-vinyl acetate copolymer having a hydroxyl group used in the present invention can be obtained by two methods. One is obtained by copolymerizing vinyl chloride monomer, vinyl acetate monomer and vinyl alcohol in an appropriate ratio. The other is obtained by saponifying a part of vinyl acetate after copolymerizing vinyl chloride and vinyl acetate. The properties of the resin film and the resin dissolution behavior of the vinyl chloride-vinyl acetate copolymer having a hydroxyl group are determined by the monomer ratio of vinyl chloride, vinyl acetate and vinyl alcohol. That is, vinyl chloride imparts toughness and hardness to the resin film, vinyl acetate imparts adhesiveness and flexibility, and vinyl alcohol imparts good solubility in polar solvents.

[0033] Moreover, as the monomer ratio of the vinyl chloride-vinyl acetate copolymer having a hydroxyl group, for example, with respect to 100 parts by mass of the vinyl chloride-vinyl acetate copolymer having a hydroxyl group, when vinyl chloride is 80 to 95 parts by mass, the balance between blocking resistance and adhesiveness is still preferable. If it is 80 parts by mass or more, the toughness of the resin film can be maintained and the blocking resistance can be ensured. If it is 95 parts by mass or less, the resin film does not become too hard and the adhesiveness is less likely to decrease. Also, the hydroxyl value obtained from vinyl alcohol is preferably 50 to 200 mgKOH / g. If it is 50 mgKOH / g or more, the solubility in polar solvents is good and the printing suitability is also likely to be stable. If it is 200 mgKOH / g or less, the laminating suitability can also be maintained well.

[0034] The vinyl-based resin is either a vinyl acetate polymer which is a homopolymer of vinyl acetate monomer, or a copolymer of vinyl acetate monomer and an unsaturated monomer copolymerizable therewith. Examples of the unsaturated monomer include long-chain (meth)acrylic monomers typified by alkyl (meth)acrylate monomers such as n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl (meth)acrylate, etc., hydroxyl group-containing (meth)acrylic monomers typified by 2-hydroxyethyl (meth)acrylate, hydroxypropyl (meth)acrylate, 1,4-butanediol mono(meth)acrylate, (poly)ethylene glycol mono(meth)acrylate, etc., carboxyl group-containing monomers such as (meth)acrylic acid, maleic acid, maleic anhydride, etc., vinyl monomers such as styrene, acrylonitrile, vinyl chloride, etc., and ethylene. These may be used alone or in combination of two or more.

[0035] The molecular weight of the vinyl-based resin is preferably 5,000 to 100,000 in terms of weight average molecular weight, more preferably 10,000 to 70,000.

[0036] The addition amount of the vinyl-based resin is 1.0 to 70.0% by mass in the ink solid content, preferably 5.0 to 50.0% by mass.

[0037] As the chlorinated vinyl-based resin used in the present invention, a vinyl-based resin obtained by chlorinating the aforementioned vinyl-based resin (also referred to as chlorinated vinyl-based resin) may be used. The chlorination method of the vinyl-based resin can be carried out by a known method. For example, the vinyl-based resin is dispersed or dissolved in a medium such as water or carbon tetrachloride, chloroform, etc., and chlorine gas is blown in at a temperature range of 50 to 120°C under pressure or normal pressure in the presence of a catalyst or under ultraviolet irradiation. Examples of the chlorinated vinyl resin include chlorinated polyolefin resins obtained by chlorinating polyolefin resins, such as chlorinated polypropylene resins obtained by chlorinating polypropylene resins, chlorinated propylene-α-olefin copolymers obtained by chlorinating propylene-α-olefin copolymers, etc., chlorinated ethylene vinyl alcohol (EVA) resins obtained by chlorinating ethylene vinyl alcohol (EVA), chlorinated ethylene-vinyl acetate copolymers obtained by chlorinating ethylene-vinyl acetate copolymers, and the like. In the case of a chlorinated polyolefin resin, its weight average molecular weight is preferably from 5,000 to 100,000, more preferably from 5,000 to 70,000, and still more preferably from 7,000 to 50,000. The chlorine content, which indicates the mass percentage of chlorine atoms in 100% by mass of the resin, is often in the range of 15 to 45% by mass. The chlorinated vinyl resin is contained in the ink solid content in an amount of 1.0 to 70% by mass, preferably 5 to 50% by mass.

[0038] Commercially available products may be used as the chlorinated vinyl resin. Chlorinated polyolefin resins, chlorinated ethylene vinyl alcohol (EVA), chlorinated ethylene-vinyl acetate copolymers, etc. are known. For example, the Super Cron series of Nippon Paper Industries Co., Ltd. can be mentioned.

[0039] (Rosin resin (A5)) As the rosin resin used in the present invention, any rosin and / or derivative of rosin that is commonly used for printing inks can be used without particular limitation. Specifically, rosin or a derivative of rosin is, for example, rosins or their carboxyl group-containing derivatives. Rosins are gum rosin, wood rosin, tall oil rosin, disproportionated rosin, hydrogenated rosin, or polymers thereof. Derivatives of rosin are carboxyl group-containing derivatives such as rosin derivatives to which unsaturated carboxylic acids such as maleic acid, itaconic acid, and crotonic acid are added. The addition amount of the rosin resin is preferably 0.1 to 20.0% by mass, more preferably 0.2 to 15.0% by mass, based on the ink solid content.

[0040] In the present invention, it is particularly preferable to use in combination a rosin-modified maleic acid resin, which is a maleic acid derivative of rosin. As the rosin-modified maleic acid resin used in the present invention, a known rosin-modified maleic acid resin can be used without particular limitation. The rosin-modified maleic acid resin preferably has an acid value of 25 mgKOH / g or more and 320 mgKOH / g or less, and particularly preferably has an acid value of 100 mgKOH / g or more and 320 mgKOH / g or less. The addition amount of the rosin-modified maleic acid resin is preferably 0.1 to 20.0% by mass based on the ink solid content, and more preferably 0.2 to 15.0% by mass.

[0041] Examples of commercially available rosin-based resins include Marukyd No. 1, 2, 5, 6, 8, 31, 32, 33, 34, 3002, etc. manufactured by Arakawa Chemical Industries, Ltd., and Harima R-80, T-80, R-100, M-453, M-130A, 135GN, 145P, R-120AH, Haritac 4851, 4821, 4740, 28JA, etc. manufactured by Harima Chemicals, Inc. In addition, these rosin-based resins can also be used as biomass raw materials. Specific examples of the rosin-modified fumaric acid resin include Arochem 475, a product name of Nippon Shokubai Co., Ltd.

[0042] (Polyamide resin) In the liquid printing ink of the present invention, a polyamide resin may be used as the binder resin. The polyamide resin is, for example, a thermoplastic polyamide soluble in an organic solvent that can be obtained by polycondensing a polybasic acid and a polyvalent amine. In particular, it is preferably a polyamide resin containing a reaction product of a fatty acid component containing polymerized fatty acid and / or dimer acid and an aliphatic and / or aromatic polyamine, and more preferably one containing a part of primary and secondary monoamines. Examples of the polybasic acids used as raw materials for polyamide resins include, but are not limited to, adipic acid, sebacic acid, azelaic acid, phthalic anhydride, isophthalic acid, suberic acid, glutaric acid, fumaric acid, pimelic acid, oxalic acid, malonic acid, succinic acid, maleic acid, terephthalic acid, 1,4-cyclohexyl dicarboxylic acid, trimellitic acid, dimer acid, hydrogenated dimer acid, polymerized fatty acid, etc. Among them, polyamide resins containing a structure derived from dimer acid or polymerized fatty acid as the main component (50% by mass or more in the polyamide resin) are preferred. Here, the polymerized fatty acid is obtained by the cyclization reaction of unsaturated fatty acids, etc., and includes monobasic fatty acids, dimerized polymerized fatty acids (dimer acid), trimerized polymerized fatty acids, etc. The fatty acids constituting the dimer acid or polymerized fatty acid are preferably those derived from natural oils such as soybean oil, palm oil, rice bran oil, etc., and those obtained from oleic acid and linoleic acid are preferred. A monocarboxylic acid can also be used in combination with the polybasic acid. Examples of the monocarboxylic acid used in combination include acetic acid, propionic acid, lauric acid, palmitic acid, benzoic acid, cyclohexanecarboxylic acid, etc.

[0043] Examples of the polyvalent amines include polyamines, primary or secondary monoamines, etc. Examples of the polyamines used in polyamide resins include aliphatic diamines such as ethylenediamine, propylenediamine, hexamethylenediamine, methylaminopropylamine, etc., aliphatic polyamines such as diethylenetriamine, triethylenetetramine, etc. Examples of the alicyclic polyamines include cyclohexylenediamine, isophoronediamine, etc. Examples of the araliphatic polyamines include xylylenediamine, and examples of the aromatic polyamines include phenylenediamine, diaminodiphenylmethane, etc. Further, examples of the primary and secondary monoamines include n-butylamine, octylamine, diethylamine, monoethanolamine, monopropanolamine, diethanolamine, dipropanolamine, etc. In addition, the amount of the polyamide resin added is 0.1 to 15.0% by mass, preferably 0.5 to 3.0% by mass, in the ink solid content.

[0044] Wax (B) In the liquid printing ink of the present invention, the following (1) and (2) are essential as the wax (B). (1) As the wax (B), it contains rice bran wax (B1) and carnauba wax (B2). (2) It contains 0.5 to 10.0% by mass in total of the rice bran wax (B1) and the carnauba wax (B2) with respect to the total solid content of the ink. The rice bran wax is not particularly limited as long as it is generally a wax derived from rice bran, which is a light brown powder obtained by pulverizing the outer skin and embryo of rice generated when polishing brown rice into polished rice. In addition, the carnauba wax includes natural carnauba wax collected from the leaves of carnauba palm of the palm family, its purified products and derivatives, and those modified with additives and the like. According to a preferred embodiment, the melting point of the carnauba wax is 80°C or higher and 90°C or lower, the acid value is 10 mg·KOH / g or lower, and the saponification value is 78 mg·KOH / g or higher and 88 mg·KOH / g or lower. Both the rice bran wax and the carnauba wax can be used as biomass raw materials. It is essential that the total amount of the rice bran wax (B1) and the carnauba wax (B2) contains 0.5 to 10.0% by mass with respect to the total solid content of the ink. If the total amount of the rice bran wax (B1) and the carnauba wax (B2) is 0.5% by mass or more, it can have scratch resistance, cellophane tape adhesion, abrasion resistance, and blocking resistance. If the total amount of the rice bran wax (B1) and the carnauba wax (B2) is 10% by mass or less, it tends to maintain plate fogging resistance and tone reproducibility.

[0045] In addition to the rice bran wax and carnauba wax, olefin waxes such as polyethylene wax and polypropylene wax, and hydrocarbon waxes such as Fischer-Tropsch wax, paraffin wax, and microcrystalline wax may be appropriately and optionally combined and used in appropriate amounts. Among them, olefin waxes such as polyethylene wax and polypropylene wax are preferred. The addition amount of the olefin wax is preferably in the range of 0.5 to 5.0% by mass based on the total solid content of the ink.

[0046] (Glycerin acetate fatty acid ester) Furthermore, in the liquid printing ink of the present invention, it is preferable to add glycerin acetate fatty acid ester. Glycerin acetate fatty acid ester is a plasticizer with a high degree of biomass mainly made from vegetable oil, and since it can prevent ink cracking during heat shrinkage, it is particularly preferable for liquid printing ink for applications such as shrink films for integrated packaging. It is preferable to add glycerin acetate fatty acid ester in an amount of 0.8 to 12.0% by mass based on the total solid content of the ink. If it is 0.8% by mass or more based on the total solid content of the ink, it tends to prevent ink cracking due to heat shrinkage during heating after printing, and if it is 12% by mass or less, the tendency of the blocking property to decrease can be suppressed. Examples of glycerin acetate fatty acid ester include "BIOCIZER" (trade name) (main component glycerin diacetate monolaurate) of Riken Vitamin Co., Ltd. The BIOCIZER uses fatty acids derived from palm kernel oil. Also, the "main component" means containing 50% by mass or more.

[0047] (Organic solvent) Although there is no particular limitation on the organic solvent used in the liquid printing ink of the present invention, for example, aromatic hydrocarbon-based organic solvents such as toluene, xylene, Solvesso #100, and Solvesso #150, aliphatic hydrocarbon-based organic solvents such as hexane, methylcyclohexane, heptane, octane, and decane, and various ester-based organic solvents such as methyl acetate, ethyl acetate, isopropyl acetate, normal propyl acetate, butyl acetate, amyl acetate, ethyl formate, and butyl propionate can be mentioned. In addition, as water-miscible organic solvents, alcohol-based solvents such as methanol, ethanol, propanol, butanol, and isopropyl alcohol, ketone-based solvents such as acetone, methyl ethyl ketone, and cyclohexanone, and various glycol ether-based organic solvents such as ethylene glycol (mono, di) methyl ether, ethylene glycol (mono, di) ethyl ether, ethylene glycol monopropyl ether, ethylene glycol monoisopropyl ether, monobutyl ether, diethylene glycol (mono, di) methyl ether, diethylene glycol (mono, di) ethyl ether, diethylene glycol monoisopropyl ether, diethylene glycol monobutyl ether, triethylene glycol (mono, di) methyl ether, propylene glycol (mono, di) methyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, and dipropylene glycol (mono, di) methyl ether can be mentioned. These can be used alone or in combination of two or more.

[0048] In addition, from the viewpoints of work hygiene during printing and the harmfulness of packaging materials, it is more preferable to use ethyl acetate, propyl acetate, isopropanol, normal propanol, etc., and not to use aromatic solvents such as toluene and ketone-based solvents such as methyl ethyl ketone.

[0049] Among them, from the viewpoint of solubility in each binder resin, a mixed solution of isopropyl alcohol:ethyl acetate:normal propyl acetate is more preferable. In addition, glycol ethers can also be added if it is less than 10% by mass of the ink solid content for drying adjustment.

[0050] (Colorant) As the liquid printing ink of the present invention, it can also be used as a varnish for adjusting the concentration of ink without a colorant and an overprint varnish, and can also be used as an ink containing a colorant for design printing and the like for the purpose of imparting beauty and the like containing a colorant. A pigment is preferably used as the colorant, and examples thereof include inorganic pigments and organic pigments used in general inks, paints, and recording agents. Examples of organic pigments include soluble azo-based, insoluble azo-based, azo-based, phthalocyanine-based, halogenated phthalocyanine-based, anthraquinone-based, ansanthrone-based, dianthraquinonyl-based, anthrapyrimidine-based, perylene-based, perinone-based, quinacridone-based, thioindigo-based, dioxazine-based, isoindolinone-based, quinophthalone-based, azomethine azo-based, flavanthrone-based, diketopyrrolopyrrole-based, isoindoline-based, indanthrone-based, carbon black-based pigments, and the like. Further, for example, carmine 6B, lake red C, permanent red 2B, disazo yellow, pyrazolone orange, carmine FB, chromophthal yellow, chromophthal red, phthalocyanine blue, phthalocyanine green, dioxazine violet, quinacridone magenta, quinacridone red, indanthrone blue, pyrimidine yellow, thioindigo Bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, daylight fluorescent pigments, and the like can be mentioned. Also, either unacid-treated pigments or acid-treated pigments can be used. Specific examples of preferred organic pigments are given below.

[0051] Examples of black pigments include C.I. Pigment Black 1, C.I. Pigment Black 6, C.I. Pigment Black 7, C.I. Pigment Black 9, C.I. Pigment Black 20, and the like.

[0052] Examples of blue pigments include C.I. Pigment Blue 15, C.I. Pigment Blue 15:1, C.I. Pigment Blue 15:2, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Blue 15:5, C.I. Pigment Blue 15:6, C.I. Pigment Blue 16, C.I. Pigment Blue 17:1, C.I. Pigment Blue 22, C.I. Pigment Blue 24:1, C.I. Pigment Blue 25, C.I. Pigment Blue 26, C.I. Pigment Blue 60, C.I. Pigment Blue 61, C.I. Pigment Blue 62, C.I. Pigment Blue 63, C.I. Pigment Blue 64, C.I. Pigment Blue 75, C.I. Pigment Blue 79, C.I. Pigment Blue 80, etc.

[0053] Examples of green pigments include C.I. Pigment Green 1, C.I. Pigment Green 4, C.I. Pigment Green 7, C.I. Pigment Green 8, C.I. Pigment Green 10, C.I. Pigment Green 36, etc.

[0054] Examples of red pigments include C.I. Pigment Red 1, C.I. Pigment Red 2, C.I. Pigment Red 3, C.I. Pigment Red 4, C.I. Pigment Red 5, C.I. Pigment Red 6, C.I. Pigment Red 7, C.I. Pigment Red 8, C.I. Pigment Red 9, C.I. Pigment Red 10, C.I. Pigment Red 11, C.I. Pigment Red 12, C.I. Pigment Red 15, C.I. Pigment Red 16, C.I. Pigment Red 17, C.I. Pigment Red 18, C.I. Pigment Red 19, C.I. Pigment Red 20, C.I. Pigment Red 21, C.I. Pigment Red 22, C.I. Pigment Red 23, C.I. Pigment Red 31, C.I. Pigment Red 32, C.I. Pigment Red 38, C.I. Pigment Red 41, C.I. Pigment Red 43, C.I. Pigment Red 46, C.I. Pigment Red 48, C.I. Pigment Red 48:1, C.I. Pigment Red 48:2, C.I. Pigment Red 48:3, C.I. Pigment Red 48:4, C.I. Pigment Red 48:5, C.I. Pigment Red 48:6, C.I. Pigment Red 49, C.I. Pigment Red 49:1, C.I. Pigment Red 49:2, C.I. Pigment Red 49:3, C.I. Pigment Red 52, C.I. Pigment Red 52:1, C.I. Pigment Red 52:2, C.I. Pigment Red 53, C.I. Pigment Red 53:1, C.I. Pigment Red 53:2, C.I. Pigment Red 53:3, C.I. Pigment Red 54, C.I. Pigment Red 57, C.I. Pigment Red 57:1, C.I. Pigment Red 58, C.I. Pigment Red 58:1, C.I. Pigment Red 58:2, C.I. Pigment Red 58:3, C.I. Pigment Red 58:4, C.I. Pigment Red 60:1, C.I. Pigment Red 63, C.I. Pigment Red 63:1, C.I. Pigment Red 63:2, C.I. Pigment Red 63:3, C.I. Pigment Red 64:1, C.I. Pigment Red 68, C.I. Pigment Red 68, C.I. Pigment Red 81:1, C.I. Pigment Red 83, C.I. Pigment Red 88, C.I. Pigment Red 89, C.I. Pigment Red 95, C.I. Pigment Red 112, C.I. Pigment Red 114, C.I. Pigment Red 119, C.I. Pigment Red 122, C.I. Pigment Red 123, C.I. Pigment Red 136, C.I. Pigment Red 144, C.I. Pigment Red 146, C.I. Pigment Red 147, C.I. Pigment Red 149, C.I. Pigment Red 150, C.I. Pigment Red 164, C.I. Pigment Red 166, C.I. Pigment Red 168, C.I. Pigment Red 169, C.I. Pigment Red 170, C.I. Pigment Red 171, C.I. Pigment Red 172, C.I. Pigment Red 175, C.I. Pigment Red 176, C.I. Pigment Red 177, C.I. Pigment Red 178, C.I. Pigment Red 179, C.I. Pigment Red 180, C.I. Pigment Red 181, C.I. Pigment Red 182, C.I. Pigment Red 183, C.I. Pigment Red 184, C.I. Pigment Red 185, C.I. Pigment Red 187, C.I. Pigment Red 188, C.I. Pigment Red 190, C.I. Pigment Red 192, C.I. Pigment Red 193, C.I. Pigment Red 194, C.I. Pigment Red 200, C.I. Pigment Red 202, C.I. Pigment Red 206, C.I. Pigment Red 207, C.I. Pigment Red 208, C.I. Pigment Red 209, C.I. Pigment Red 210, C.I. Pigment Red 211, C.I. Pigment Red 213, C.I. Pigment Red 214, C.I. Pigment Red 216, C.I. Pigment Red 215, C.I. Pigment Red 216, C.I. Pigment Red 220, C.I. Pigment Red 221, C.I. Pigment Red 223, C.I. Pigment Red 224, C.I. Pigment Red 226, C.I. Pigment Red 237, C.I. Pigment Red 238, C.I. Pigment Red 239, C.I. Pigment Red 240, C.I. Pigment Red 242, C.I. Pigment Red 245, C.I.Examples include Pigment Red 247, C.I. Pigment Red 248, C.I. Pigment Red 251, C.I. Pigment Red 253, C.I. Pigment Red 254, C.I. Pigment Red 255, C.I. Pigment Red 256, C.I. Pigment Red 257, C.I. Pigment Red 258, C.I. Pigment Red 260, C.I. Pigment Red 262, C.I. Pigment Red 263, C.I. Pigment Red 264, C.I. Pigment Red 266, C.I. Pigment Red 268, C.I. Pigment Red 269, C.I. Pigment Red 270, C.I. Pigment Red 271, C.I. Pigment Red 272, C.I. Pigment Red 279, and the like.

[0055] Examples of the purple pigment include, for example, C.I. Pigment Violet 1, C.I. Pigment Violet 2, C.I. Pigment Violet 3, C.I. Pigment Violet 3:1, C.I. Pigment Violet 3:3, C.I. Pigment Violet 5:1, C.I. Pigment Violet 13, C.I. Pigment Violet 19 (γ type, β type), C.I. Pigment Violet 23, C.I. Pigment Violet 25, C.I. Pigment Violet 27, C.I. Pigment Violet 29, C.I. Pigment Violet 31, C.I. Pigment Violet 32, C.I. Pigment Violet 36, C.I. Pigment Violet 37, C.I. Pigment Violet 38, C.I. Pigment Violet 42, C.I. Pigment Violet 50, and the like.

[0056] Examples of yellow pigments include, for example, C.I. Pigment Yellow 1, C.I. Pigment Yellow 3, C.I. Pigment Yellow 12, C.I. Pigment Yellow 13, C.I. Pigment Yellow 14, Pigment Yellow 17, C.I. Pigment Yellow 24, C.I. Pigment Yellow 42, C.I. Pigment Yellow 55, C.I. Pigment Yellow 62, C.I. Pigment Yellow 65, C.I. Pigment Yellow 74, C.I. Pigment Yellow 83, C.I. Pigment Yellow 86, C.I. Pigment Yellow 93, C.I. Pigment Yellow 94, C.I. Pigment Yellow 95, C.I. Pigment Yellow 109, C.I. Pigment Yellow 110, C.I. Pigment Yellow 117, C.I. Pigment Yellow 120, Pigment Yellow 125, C.I. Pigment Yellow 128, C.I. Pigment Yellow 129, C.I. Pigment Yellow 137, C.I. Pigment Yellow 138, C.I. Pigment Yellow 139, C.I. Pigment Yellow 147, C.I. Pigment Yellow 148, C.I. Pigment Yellow 150, C.I. Pigment Yellow 151, C.I. Pigment Yellow 153, C.I. Pigment Yellow 154, C.I. Pigment Yellow 155, C.I. Pigment Yellow 166, C.I. Pigment Yellow 168, C.I. Pigment Yellow 174, C.I. Pigment Yellow 180, C.I. Pigment Yellow 185, and C.I. Pigment Yellow 213, etc.

[0057] Examples of orange pigments include, for example, C.I. Pigment Orange 5, C.I. Pigment Orange 13, C.I. Pigment Orange 16, C.I. Pigment Orange 34, C.I. Pigment Orange 36, C.I. Pigment Orange 37, C.I. Pigment Orange 38, C.I. Pigment Orange 43, C.I. Pigment Orange 51, C.I. Pigment Orange 55, C.I. Pigment Orange 59, C.I. Pigment Orange 61, C.I. Pigment Orange 64, C.I. Pigment Orange 71, or C.I. Pigment Orange 74, etc.

[0058] Examples of the brown pigment include C.I. Pigment Brown 23, C.I. Pigment Brown 25, or C.I. Pigment Brown 26.

[0059] Among them, as a preferred pigment, C.I. Pigment Black 7 as a black pigment C.I. Pigment Blue 15, C.I. Pigment Blue 15:1, C.I. Pigment Blue 15:2, C.I. Pigment Blue 15:3, C.I. Pigment Blue 15:4, C.I. Pigment Blue 15:6 as blue pigments C.I. Pigment Green 7 as a green pigment C.I. Pigment Red 57:1, C.I. Pigment Red 48:1, C.I. Pigment Red 48:2, C.I. Pigment Red 48:3, C.I. Pigment Red 146, C.I. Pigment Red 242, C.I. Pigment Red 185, C.I. Pigment Red 122, C.I. Pigment Red 178, C.I. Pigment Red 149, C.I. Pigment Red 144, C.I. Pigment Red 166 as red pigments C.I. Pigment Violet 23, C.I. Pigment Violet 37 as purple pigments C.I. Pigment Yellow 83, C.I. Pigment Yellow 14, C.I. Pigment Yellow 180, C.I. Pigment Yellow 139 as yellow pigments C.I. Pigment Orange 38, C.I. Pigment Orange 13, C.I. Pigment Orange 34, C.I. Pigment Orange 64 as orange pigments and the like are included, and it is preferable to use at least one or two or more selected from these groups.

[0060] Examples of inorganic pigments include white inorganic pigments such as titanium oxide, zinc oxide, zinc sulfide, barium sulfate, calcium carbonate, chromium oxide, silica, lithopone, antimony white, and gypsum. Among the inorganic pigments, the use of titanium oxide is particularly preferred. Titanium oxide exhibits white color and is preferred in terms of coloring power, hiding power, chemical resistance, and weather resistance. From the viewpoint of printing performance, the titanium oxide preferably has been treated with silica and / or alumina.

[0061] Examples of inorganic pigments other than white include, for example, aluminum particles, mica, bronze powder, chrome vermilion, lead yellow, cadmium yellow, cadmium red, ultramarine, cobalt blue, red iron oxide, iron black, and zircon. Aluminum is in the form of powder or paste, and it is preferably used in the form of paste from the viewpoints of handleability and safety. Whether to use leafing or non-leafing is appropriately selected from the viewpoints of brightness and density.

[0062] The pigment is preferably contained in an amount sufficient to ensure the density and coloring power of the liquid printing ink, that is, in a proportion of 1 to 60% by mass based on the total mass of the ink and 10 to 90% by mass in terms of the solid content weight ratio in the ink. These pigments can be used alone or in combination of two or more.

[0063] The liquid printing ink of the present invention may further contain, if necessary, extender pigments, leveling agents, defoaming agents, plasticizers, infrared absorbers, ultraviolet absorbers, fragrances, flame retardants, and the like. For example, if an appropriate amount of silica is added as the extender pigment, the friction resistance tends to be improved.

[0064] The liquid printing ink of the present invention can be produced by dissolving and / or dispersing a binder resin, a pigment, etc. in an organic solvent. Specifically, a pigment dispersion in which a pigment is dispersed in an organic solvent with a binder resin is produced, and the obtained pigment dispersion is blended with other compounds, etc. as necessary to produce the ink.

[0065] 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 disperser, 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 disperser, generally used ones such as a roller mill, a ball mill, a pebble mill, an attritor, a sand mill, etc. can be used. When the ink contains bubbles, unexpectedly large particles, etc., it is preferable to remove them by filtration or the like in order to reduce the print quality. As the filter, a conventionally known one can be used.

[0066] The ink viscosity produced by the above method is preferably in the range of 10 mPa·s or more from the viewpoint of preventing the sedimentation of the pigment and dispersing it appropriately, and 1000 mPa·s or less from the viewpoint of workability efficiency during ink production and printing. Incidentally, the above viscosity is the viscosity measured at 25 °C with a B-type viscometer manufactured by Tokimec Co., Ltd. The viscosity of the ink can be adjusted by appropriately selecting the types and amounts of the raw materials used, the binder resin, the pigment, the organic solvent, etc. Also, the viscosity of the ink can be adjusted by adjusting the particle size and particle size distribution of the pigment in the ink.

[0067] (Printed matter and laminate) A printed matter is obtained by printing the liquid printing ink of the present invention on an arbitrary substrate. The substrate used in the present invention is not particularly limited, and a paper or plastic substrate usually used in the gravure / flexographic printing field, or a flexible packaging substrate used in the food packaging field may be used. For example, in the case of paper, high-quality paper, kraft paper, pure white roll paper, glassine paper, parchment paper, manila board, white board, coated paper, art paper, imitation paper, thin paper, thick paper, polyethylene-coated paper, etc. used for printing packaging and packages of cosmetics, beverages, pharmaceuticals, toys, equipment, etc., various synthetic papers, etc. can be mentioned.

[0068] The film substrate is made of biodegradable resins such as polyamide resins like nylon 6, nylon 66, nylon 46, polyester resins such as polyethylene terephthalate (hereinafter sometimes referred to as PET), polyethylene naphthalate, polytrimethylene terephthalate, polytrimethylene naphthalate, polybutylene terephthalate, polybutylene naphthalate, polyhydroxycarboxylic acids such as polylactic acid, aliphatic polyester resins such as poly(ethylene succinate), poly(butylene succinate), thermoplastic resins such as polyolefin resins like polypropylene, polyethylene, polyimide resins, polyarylate resins or mixtures thereof, etc. Among them, films made of polyethylene terephthalate (PET), polyester, polyamide, polyethylene, polypropylene are preferably used. These base films may be unstretched films or stretched films, and their manufacturing methods are not limited. Also, the thickness of the base film is not particularly limited, but usually it may be in the range of 1 to 500 μm. The printing surface of the base film is preferably subjected to corona discharge treatment, and aluminum, silica, alumina, etc. may be vapor-deposited. Moreover, if these base materials are plastic base materials containing biomass raw materials, it is more preferable because the biomass conversion ratio can be further increased by the synergistic effect with each biomass raw material such as rice bran wax, carnauba wax, cellulose of fiber-based resin, rosin-modified fumaric acid resin, glycerin acetic fatty acid ester.

[0069] (Film for integrated packaging) The liquid printing ink of the present invention may be used as a printing ink for a heat-shrinkable film used as a film for integrated packaging. Examples of the resin used for the heat shrinkable film include one kind or a mixture of two or more kinds selected from thermoplastic resins such as polyester resins such as polyethylene terephthalate resins and polylactic acid resins, polyolefin resins such as polyethylene resins and polypropylene resins, polystyrene resins, polyvinyl chloride resins, and polyamide resins. Among these, resin films such as polyester resins, polyolefin resins, and polystyrene resins are often used from the viewpoints of shrinkage characteristics and the like. Since the liquid printing ink of the present invention has good adhesion particularly to polyolefin resins, a polyolefin resin film is preferred, and it is particularly preferred to use a polyethylene resin or a polypropylene resin. The heat shrinkable film may be a single-layer film or a multilayer film having a plurality of layers. In the case of a multilayer film, it may have a heat seal layer as the layer constituting the back surface.

[0070] The thickness of the heat shrinkable film is not particularly limited, but from the viewpoints of strength, rigidity, shrinkage characteristics, economy, etc., it is preferably 5 to 120 μm, more preferably 7 to 100 μm, and particularly preferably 10 to 80 μm. The heat shrinkable film is preferably transparent (colorless transparent or colored transparent), more preferably colorless transparent, so as to make the printing layer of the liquid printing ink of the present invention visible through.

[0071] In order for the heat shrinkable film to exhibit good heat shrinkability, it is preferably stretched (uniaxially stretched) in at least one direction, and particularly preferably biaxially stretched. The stretching temperature varies depending on the type of resin constituting the film, but is, for example, 60 to 130°C. The stretching ratio is preferably about 2 to 8 times in the main stretching direction in the case of a uniaxially stretched film, and in both one direction and the other direction orthogonal to the one direction in the case of a biaxially stretched film. As the stretching method, a roll method, a tenter method, a tube method, etc. can be used.

[0072] The heat shrinkage rate of the heat shrinkable film is 20% or more with respect to the main stretching direction in the case of a uniaxially stretched film, and 20% or more in both directions (one direction and the other direction) in the case of a biaxially stretched film, preferably 30 to 80%, particularly preferably 40 to 80% (heat treatment conditions: immersed in warm water at 90°C for 10 seconds). In the case of a uniaxially stretched film, with respect to the direction orthogonal to the main stretching direction, it is preferably -3 to 15%, more preferably -1 to 10%, particularly preferably -1 to 5% (heat treatment conditions: the same as above).

[0073] Also, if necessary, an ink-receiving layer for facilitating printing may be provided on the heat shrinkable film. As described above, the liquid printing ink of the present invention can improve the adhesion and blocking resistance even in a biaxially stretched polypropylene film that has not been subjected to corona discharge treatment, and can exhibit the effects of the present invention to the maximum extent.

Examples

[0074] The present invention will be described more specifically by way of examples. Hereinafter, both "parts" and "%" are based on mass. Also, unless otherwise specified, solid content is indicated for components other than organic solvents.

[0075] (Acrylic resin) As the acrylic resin, "Product name: Acridic WCL-1419, weight average molecular weight: 35,000" manufactured by DIC Corporation was used.

[0076] (Polyurethane resin) As the polyurethane resin, "Product name: Barnock ECL-341, weight average molecular weight 85,000" manufactured by DIC Corporation was used.

[0077] (Preparation of cellulose acetate propionate resin solution Ca) To 20 parts of cellulose acetate propionate CAP482-0.5 (manufactured by Eastman Chemical), 80 parts of a mixed solution of isopropyl alcohol / ethyl acetate / n-propyl acetate / methylcyclohexane (ratio of 25 / 25 / 13 / 10 by weight) was added and thoroughly mixed to prepare a cellulose ester resin solution Ca.

[0078] (Preparation of vinyl chloride-vinyl acetate copolymer resin solution Ev) A vinyl chloride-vinyl acetate copolymer resin having a hydroxyl group (resin monomer composition: vinyl chloride / vinyl acetate / vinyl alcohol = 92 / 3 / 5 by mass%, hydroxyl value (mgKOH) = 64) was made into a 25% solution with ethyl acetate, and this was used as the vinyl chloride-vinyl acetate copolymer resin solution Ev.

[0079] (Rosin-modified fumaric acid resin) As the rosin-modified fumaric acid resin, "Product name: Markid No. 31, weight average molecular weight: 1200" manufactured by Arakawa Chemical Industries, Ltd. was used.

[0080] [Example 1] 15.26 parts of an acrylic resin "Product name: Acridic WCL-1419, weight average molecular weight: 35,000" manufactured by DIC, 5.09 parts of the solid content of the cellulose acetate propionate resin solution Ca, 68.49 parts of titanium oxide JR-780 (manufactured by Teika Co., Ltd.), 3.86 parts of glycerin acetate fatty acid ester as a plasticizer, 1.4 parts of polyethylene wax 1 (average particle diameter: 7 μm), 3.0 parts of ester wax derived from rice bran, 2.53 parts of carnauba wax compound, and 0.37 part of spherical polyethylene wax 2 (average particle diameter: 10 μm) as a slip-imparting agent, a total of 100.01 parts of the total solid content, 48 parts of a mixed organic solvent with a mass ratio of isopropyl alcohol:ethyl acetate:n-propyl acetate of 4:2:1 was added and kneaded to prepare a white liquid printing ink.

[0081] [Examples 2 to 18 and Comparative Examples 1 to 16] According to the formulations shown in Tables 1 to 8, each liquid printing ink was prepared in the same procedure as in Example 1. For the blue inks of Examples 12 to 18 and Comparative Examples 11 to 16, a blue liquid printing ink was used in which FASTGEN Blue LA5380: C.I. Pigment Blue 15, a phthalocyanine-based blue pigment (manufactured by DIC Corporation), was used instead of the titanium oxide JR-780.

[0082] (Production of Printed Matter) Each of the prepared liquid printing inks was applied to a biaxially stretched polystyrene sheet film, a hybrid styrene sheet film, or a polyethylene terephthalate film (all with a thickness of 40 μm) without corona discharge treatment using a bar coater #10, and left for 24 hours to create a printed matter.

[0083] [Adhesion] For each of the printed matters, after attaching cellophane tape (manufactured by Nichiban Co., Ltd.) to the printed surface, the tape was quickly peeled off, and the state of the printed surface was visually evaluated. (Evaluation Criteria) 7: The printed film does not peel off from the film at all. 6: As the area ratio of the printed film, less than 5% peels off from the film. 5: As the area ratio of the printed film, less than 15% peels off from the film. 4: As the area ratio of the printed film, less than 30% peels off from the film. 3: As the area ratio of the printed film, 30% or more and less than 50% peels off from the film. 2: As the area ratio of the printed film, 50% or more and less than 75% peels off from the film. 1: As the area ratio of the printed surface, 75% or more peels off from the film.

[0084] [Scratch Resistance] For each of the printed matters, the printed surface was rubbed 20 times back and forth with a fingernail, and the state of the ink being scraped off was visually evaluated. (Evaluation Criteria) 7: The printed film does not peel off from the film at all. 6: As the area ratio of the printed film, less than 5% peels off from the film. 5: As the area ratio of the printed film, less than 15% peels off from the film. 4: As the area ratio of the printed film, less than 30% peels off from the film. 3: As the area ratio of the printed film, 30% or more and less than 50% peels off from the film. 2: As the area ratio of the printed film, 50% or more and less than 75% peels off from the film. 1: As the area ratio of the printed surface, 75% or more peels off from the film.

[0085] 〔Abrasion resistance〕 For each of the above-mentioned printed matters, on the printed surface, using black high-quality paper for the friction paper and a commercially available Gakushin type friction fastness tester, it was evaluated under the conditions of a load of 500 g and 100 reciprocations. (Evaluation criteria) 7: The rubbed black high-quality paper is not colored at all. 6: The rubbed black high-quality paper is colored very thinly to a medium degree between evaluation "7" and "5". 5: The rubbed black high-quality paper is colored thinly to a medium degree between evaluation "6" and "4". 4: The rubbed black high-quality paper is thinly colored but within the practical range. 3: The rubbed black high-quality paper is colored to a medium degree between evaluation "4" and "2". 2: The rubbed black high-quality paper is colored to a medium degree between evaluation "3" and "1". 1: The rubbed black high-quality paper is colored darkly.

[0086] 〔Blocking resistance〕 For each of the above-mentioned printed matters, the printed surfaces were put together and left for 1 day under the conditions of pressure: 0.5 MPa, temperature: 50 °C, and humidity: 80% using a blocking tester, and the peelability and state of the surface after the test were evaluated. (Evaluation criteria) 7: When peeling the printed surfaces from each other, they peel off without resistance and there is no particular problem with the surface. 6: When peeling the printed surfaces from each other, there is some resistance, but there is no particular problem with the surface. 5: When peeling the printed surfaces from each other, there is some resistance, and it can be seen that the surface is slightly stuck. 4: When separating the printed surfaces, there is resistance and it can be seen that the surfaces are slightly stuck together. 3: When separating the printed surfaces, there is resistance and it can be seen that the surfaces are stuck together. 2: When separating the printed surfaces, there is quite a lot of resistance and it can be seen that the surfaces are strongly stuck together. 1: When separating the printed surfaces, they are stuck and cannot be separated.

[0087] 〔Slip property〕 For each of the above-mentioned printed matters, using a commercially available friction tester, a film with a width of 65 mm and a length of 65 mm was prepared as a test piece, and the dynamic friction coefficient between the printed surface and polyethylene terephthalate (E5101 100 μm manufactured by Toyobo) was measured at a load of 200 g, a speed of 300 mm / min, and a running distance of 50 mm. (Evaluation criteria) 7: Dynamic friction coefficient 0 to less than 0.2 6: Dynamic friction coefficient 0.2 or more to less than 0.3 5: Dynamic friction coefficient 0.3 or more to less than 0.4 4: Dynamic friction coefficient 0.4 or more to less than 0.5 3: Dynamic friction coefficient 0.5 or more to less than 0.6 2: Dynamic friction coefficient 0.6 or more to less than 0.8 1: Dynamic friction coefficient 0.8 or more

[0088] 〔Plate doubling property〕 The viscosity of each of the prepared liquid printing inks was adjusted to 16 seconds (25 °C) with a Zahn cup #3 (manufactured by Rika Shakai) using a mixed organic solvent of ethyl acetate / isopropyl alcohol = 50 / 50, and printing was performed on a biaxially stretched polystyrene sheet film, or a hybrid styrene sheet film, or a polyethylene terephthalate film (all with a thickness of 40 μm) without corona discharge treatment using an MD type gravure printing machine (manufactured by Fuji Machinery Co., Ltd.) equipped with a laser gravure plate having a plate depth of 30 μm. The degree of contamination (plate doubling degree) of the highlight non-printing part at a printing speed of 200 m / min with a circumferential length of 600 mmΦ of the gravure plate was visually evaluated. (Evaluation criteria) 7: There is no stain on the non-printing part. 6: The stain on the non-printing part is less than 5% of the total area ratio. 5: The stain on the non-printing part is 5% or more and less than 15% of the total area ratio. 4: The stain on the non-printing part is 15% or more and less than 25% of the total area ratio. 3: The stain on the non-printing part is 25% or more and less than 35% of the total area ratio. 2: The stain on the non-printing part is 35% or more and less than 50% of the total area ratio. 1: The stain on the non-printing part is 50% or more of the total area ratio.

[0089] 〔Harmony reproducibility〕 The evaluation of harmony reproducibility was carried out by dot gain, which compared the area of the cell opening of the 50% halftone part of the gravure plate with the area of the 50% halftone part of the printed matter when printing 4000 m with a gravure plate of 600 mmΦ in circumference at 200 m / min. In gravure printing, if the halftone dots spread wider than the actual area of the cell opening, the reproduction of color tones and the like deteriorates. Therefore, it is desirable that the halftone dots of the printed matter be close to the area of the cell opening. (Evaluation criteria) 7: The area of the halftone dots of the printed matter is in the range of 100% - 105% compared to the area of the cell opening. 6: The area of the halftone dots of the printed matter is in the range of 106% - 110% compared to the area of the cell opening. 5: The area of the halftone dots of the printed matter is in the range of 111% - 120% compared to the area of the cell opening. 4: The area of the halftone dots of the printed matter is in the range of 121% - 130% compared to the area of the cell opening. 3: The area of the halftone dots of the printed matter is in the range of 131% - 140% compared to the area of the cell opening. 2: The area of the halftone dots of the printed matter is in the range of 141% - 160% compared to the area of the cell opening. 1: The area of the halftone dots of the printed matter is 161% or more compared to the area of the cell opening.

[0090] The formulations and evaluation results of each white or blue liquid printing ink are shown in Tables 1 to 8. Solid content is shown except for organic solvents. Note that the blank cells in the table indicate non-formulation. OPS of the substrate indicates a biaxially oriented polystyrene sheet film, and PET indicates a polyethylene terephthalate film.

[0091]

Table 1

[0092]

Table 2

[0093]

Table 3

[0094]

Table 4

[0095]

Table 5

[0096]

Table 6

[0097]

Table 7

[0098]

Table 8

Claims

1. A liquid printing ink for printing on a paper substrate or a plastic substrate, which contains a binder resin (A) and a wax (B) and satisfies the following (1) to (4). (1) As the wax (B), it contains rice bran wax (B1) and carnauba wax (B2). (2) It contains 0.5 to 10.0% by mass in total of the rice bran wax (B1) and the carnauba wax (B2) based on the total solid content of the ink. (3) The binder resin (A) is any one of (3-1) to (3-3). (3-1) It contains an acrylic resin (A1) and a cellulose resin (A3). (3-2) It contains a polyurethane resin (A2) and a cellulose resin (A3). (3-3) It contains a polyurethane resin (A2), a cellulose resin (A3), a chlorinated vinyl resin (A4), and a rosin resin (A5). (4) It contains a pigment at a ratio of 10 to 90% by mass based on the solid content weight ratio in the ink.

2. The liquid printing ink according to Claim 1, which is for surface printing.

3. The liquid printing ink according to Claim 1 or 2, which further contains an olefin wax (B3).

4. The liquid printing ink according to any one of Claims 1 to 3, wherein the mass ratio (B1) / (B2) of the rice bran wax (B1) and the carnauba wax (B2) is in the range of (B1) / (B2)=1 / 10 to 2 / 1.

5. The liquid printing ink according to any one of Claims 1 to 4, wherein glycerin acetate fatty acid ester is further added at 0.8 to 12.0% by mass based on the total solid content of the ink.

6. The liquid printing ink according to any one of Claims 1 to 5, wherein the binder resin (A) in (3) is any one of (3-1') to (3-3'). (3-1') It contains an acrylic resin and cellulose acetate propionate. (3-2') It contains a polyurethane resin and cellulose propionate. (3-3') It contains a polyurethane resin, cellulose propionate, a chlorinated vinyl / vinyl acetate copolymer, and a rosin-modified fumaric acid resin.

7. A printed matter printed with the liquid printing ink according to any one of Claims 1 to 6 on a paper substrate or a plastic substrate.

8. An integrated packaging film printed with the liquid printing ink according to any one of Claims 1 to 6 on a heat-shrinkable plastic substrate.

9. A printed matter printed with the liquid printing ink according to any one of claims 1 to 6 on a plastic substrate containing a biomass raw material.

10. An integrated packaging film printed with the liquid printing ink according to any one of claims 1 to 6 on a heat-shrinkable biomass plastic substrate.

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