JP7036099B2 - Organic solvent-based printing inks, printed matter and laminates - Google Patents

Description

The present invention relates to an organic solvent-based printing ink, and a printed matter and a laminate using the same.

In recent years, packages made from plastic films, plastic bottles and other plastic products have been disposed of and dumped as garbage in the ocean, which has become an environmental pollution problem. These plastic products are decomposed in seawater into submicron-sized fragments (microplastics) that float in seawater. When the plastic is ingested by marine organisms such as fish, it is concentrated in the organism. Then, there is a concern that it will affect the health of seabirds and humans who ingest the marine organisms as food.
In the case of a laminated package as shown below, ink, adhesives, and harmful substances caused by the coating layer are also attached to the surface of the microplastic, which is more concerned about environmental protection. There is. Various efforts have begun to reduce microplastics to remedy these problems.

Examples of the plastic products include food packaging packages using a plastic base material. In the package, various plastic base materials such as polyester base material (PET), nylon base material (NY), polypropylene base material (OPP), and metal vapor deposition base materials thereof are used as the film base material. A pattern layer is applied to these with gravure ink, flexo ink, or other printing ink, and the laminate is further bonded to a heat-melt resin base material via an adhesive or the like to form a (laminate) laminate, and then the laminate is cut. It is heat-sealed to form a package. As the package form, there are a form in which the pattern layer is the outermost layer of the package (referred to as front printing) and a form in which the pattern layer exists as an intermediate layer between the base materials (referred to as laminating or back printing).

As an attempt to reduce the amount of microplastics, in the above package, (1) the plastic base material is replaced with paper, and (2) the plastic base material is limited to the use of only the same type to simplify recycling (referred to as monomaterialization). , (3) Remove impurities and recycle plastic.

In the above (1), if paper is used as a raw material, it is promising in terms of safety and recyclability, but it becomes a problem because its gas barrier property and water resistance are inferior to those of a plastic base material. Although studies are being conducted on coating agents for paper, there are high hurdles for practical use. The above (2) is an attempt to recycle a plastic base material by forming a package with only a polyolefin base material such as polypropylene. However, there is a problem that the performance cannot be obtained with the polyolefin base material in the usage form in which high functions such as retort resistance and light shielding property are required in the first place. Therefore, the technology development for (3) above has been carried out after comprehensively considering the efficiency of recycling and the performance of the package.

As the above (3), an attempt has been made to remove the pattern layer (front printing ink layer) on the outer surface of the package, which becomes an impurity in the recycling process of the plastic base material, with an alkaline aqueous solution. For example, Cited Document 1 discloses a technique in which an undercoat layer made of an acrylic resin or a styrene maleic acid resin is provided on a plastic base material, and a front print layer arranged on the undercoat layer is removed with alkaline water. .. Further, Patent Document 2 discloses a technique of printing an ink using a polyurethane resin having an acidic group or an acrylic resin as a binder resin and removing the printing layer with alkaline water. However, these are techniques only for removing the front printing ink on the outside of the package, and have not yet removed the ink layer in the laminated laminate and peeled off the base materials from each other.

In addition to removing the front printing ink layer for plastic recycling, the technology for removing the ink layer in the laminated laminate is an important technology that can be industrially used for environmental protection in promoting plastic recycling. However, the technology that can achieve both of these has not yet been reported.

Japanese Unexamined Patent Publication No. 2001-131484 Japanese Unexamined Patent Publication No. 11-209677

INDUSTRIAL APPLICABILITY The present invention has good print processing suitability, can desorb ink and the like from a plastic film with an alkaline aqueous solution in a laminate having a front printing structure and a laminated structure, and has good retort suitability in a laminated structure. It is an object of the present invention to provide an organic solvent-based printing ink that expresses the above.

As a result of diligent research on the subject of the present invention, the present inventor has found that the problem can be solved by using the organic solvent-based printing ink described below, and has come to the present invention.

That is, the present invention is an organic solvent-based printing ink containing a clear ink or a color ink for forming a desorption layer, and the printing ink contains a polyurethane resin having an acid value of 15 to 70 mgKOH / g as a binder resin. Regarding organic solvent-based printing inks.

The present invention also relates to the organic solvent-based printing ink in which the molecular weight distribution (Mw / Mn) of the polyurethane resin is 6 or less.

Further, the present invention is the organic solvent-based printing ink, wherein the polyurethane resin contains a structural unit derived from a polyol, and the structural unit derived from a polyester polyol is contained in an amount of 5% by mass or more in the total mass of the structural unit.

The present invention also relates to the organic solvent-based printing ink in which the acid value of the polyurethane resin is 20 to 50 mgKOH / g.

The present invention also relates to a printed matter having a desorption layer made of the organic solvent-based printing ink on the base material 1.

The present invention also relates to a laminate having at least a base material 1, a desorbing layer made of the organic solvent-based printing ink, and a base material 2.

By using the organic solvent-based printing ink of the present invention, the ink and the like can be desorbed from the plastic film by the alkaline aqueous solution in the laminated body in the front printing structure and the laminated structure, and the good retort suitability in the laminated structure. We were able to provide an organic solvent-based printing ink that expresses the above.

Hereinafter, embodiments of the present invention will be described in detail, but the embodiments or requirements described below are examples of embodiments of the present invention, and the present invention includes these contents as long as the gist thereof is not exceeded. Not limited.

In the following description, "organic solvent-based printing ink" may be simply abbreviated as "printing ink" or "ink", but they have the same meaning. Further, a printing layer made of an organic solvent-based printing ink is referred to as a "desorption layer", and may be simply referred to as an "ink layer", but they have the same meaning. On the other hand, the printing ink having no desorption function is called "picture ink", and the printing layer is called "picture ink layer" or "picture layer".

The present invention is an organic solvent-based printing ink containing a clear ink or a color ink for forming a desorption layer, and the printing ink contains a polyurethane resin having an acid value of 15 to 70 mgKOH / g as a binder resin. It is an organic solvent-based printing ink. However, the ink excludes the case where the acid value of the polyurethane resin is neutralized in the ink.

The organic solvent-based printing ink is organic solvent-based and contains a polyurethane resin having an acid value of 15 to 70 mgKOH / g as a binder resin, so that desorption resistance and retort resistance are improved. When the acid value is 15 mgKOH / g or more, the desorption property of the ink layer is improved by the neutralizing action of the polyurethane resin and the alkaline aqueous solution. When the acid value is 70 mgKOH / g or less, the adhesion between the ink layer and the plastic film is improved, and the retort resistance is improved.

The above-mentioned "desorption" means peeling by swelling, dissolution, erosion, etc. with a basic (alkaline) aqueous solution. The basic aqueous solution used is not particularly limited, but sodium hydroxide (NaOH), potassium hydroxide (KOH), calcium hydroxide (Ca (OH) ₂ ), ammonia, barium hydroxide ( Ba (OH) ₂ ), sodium carbonate (Na ₂ CO ₃ ) and the like are preferably mentioned. It is preferably NaOH or KOH. However, the form of the desorption condition of the present invention is not limited to these.

The peeling with the alkaline aqueous solution has a feature including not only the peeling of the desorption layer but also the peeling of the pattern layer, the adhesive layer, the base material 1 and the base material 2 described later together with the peeling of the desorption layer.

The desorption layer in the present invention is formed from the organic solvent-based printing ink described below. First, a polyurethane resin contained as a binder resin in an organic solvent-based printing ink will be described. The binder resin refers to a main resin component for forming a desorbed layer.

<Polyurethane resin>
The polyurethane resin used in the organic solvent-based printing ink of the present invention is characterized by having an acid value of 15 to 70 mgKOH / g. The acid value is a value obtained by converting the amount of acid in 1 g of the resin calculated by titrating the acid with an alkali into the number of mg of potassium hydroxide, and is a value measured according to JIS K0070. When the acid value is 15 mgKOH / g or more, the ink can be easily removed with an alkaline aqueous solution. When the acid value is 70 mgKOH / g or less, the adhesion to the plastic film and the water resistance are good, and as a result, the retort resistance is good. From the viewpoint of the balance between alkali desorption and retort resistance, the acid value of the polyurethane resin is preferably 20 to 50 mgKOH / g, more preferably 25 to 50 mgKOH / g, and even more preferably 25 to 45 mgKOH / g. It is more preferably g.

The molecular weight distribution (Mw / Mn) of the polyurethane resin is preferably 6 or less. Mw represents a weight average molecular weight, and Mn represents a number average molecular weight. When Mw / Mn is 6 or less, the influence caused by an excessive high molecular weight component, an unreacted component, a side reaction component and other low molecular weight components can be avoided, and the detachability, drying property and retort resistance are suitable. Becomes good. Further, when the molecular weight distribution is smaller (the molecular weight distribution is sharp), the action of uniform contact with the alkaline aqueous solution is exhibited, and the desorption property by the alkali becomes better. The molecular weight distribution is more preferably 5 or less, and even more preferably 4 or less. The molecular weight distribution is preferably 1.5 or more, and more preferably 1.2 or more. In addition, Mw, Mn and Mw / Mn are values using polystyrene conversion values which can be obtained by gel permeation chromatography (GPC). If the molecular weight distribution is within the corresponding range and the acid value is within the above range, the alkali desorption property, drying property, retort resistance, etc. are sufficiently satisfied.

In order to keep the molecular weight distribution (Mw / Mn) in the above range, in polyurethane resin synthesis, the ratio of urethane synthetic raw material / organic solvent (solid content ratio), the dropping rate of reactive raw materials such as polyisocyanate, and further, during the reaction It can be within the range by appropriately setting the stirring speed and the uniformity of the reaction solution. When the chain extension reaction is further carried out, the molecular weight distribution can be set within a predetermined range by appropriately controlling the stirring speed, the dropping speed, and the temperature. Further, the molecular weight distribution can be set within a predetermined range by setting the charging ratio of the reaction raw material to an appropriate ratio. The charging ratio includes, for example, the NCO / OH ratio, which is the ratio of the hydroxyl group of the polyol and hydroxyic acid to the isocyanate group of the polyisocyanate, and is the ratio of the amino group of the polyamine to the isocyanate group of the urethane prepolymer. , Amino group / NCO ratio and the like. In order to control the molecular weight distribution, it is preferable to use a polymerization inhibitor for the purpose of preventing an excessive reaction. Preferable examples of the polymerization terminator are monoalcohols and monoamines.

The weight average molecular weight (Mw) of the polyurethane resin is preferably 10,000 to 100,000. It is still more preferably 15,000 to 70,000, and even more preferably 15,000 to 50,000. This is because the blocking resistance, work efficiency in the printing process of the organic solvent-based printing ink, printability, and the like are improved. Further, the above molecular weight distribution improves the desorption property by alkali.

The polyurethane resin may have an amine value and / or a hydroxyl value, and when it has an amine value, it is preferably 0.1 to 20 mgKOH / g, and more preferably 1 to 15 mgKOH / g. This is because the adhesion to the base material is good. When it has a hydroxyl value, it is preferably 0.1 to 20 mgKOH / g, and more preferably 1 to 15 mgKOH / g. This is because the solubility is good.

The polyurethane resin used in the present invention is not limited depending on the production method thereof, but it is preferable to use, for example, a polyurethane resin obtained by reacting a polyisocyanate, a polyol and a hydroxy acid.
Further, it is still preferable to use a polyurethane resin obtained by further reacting a urethane prepolymer obtained by reacting a polyisocyanate, a polyol and a hydroxy acid with a polyamine (referred to as a chain extension reaction). In any of the above cases, the polyurethane resin used in the present invention can be imparted with an acid value by using a hydroxy acid.

(Polyisocyanate)
As the polyisocyanate used in the polyurethane resin used in the organic solvent-based printing ink of the present invention, diisocyanate and / or triisocyanate are preferable, and aromatic, aliphatic or alicyclic diisocyanates can be preferably used.
For example, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzylisocyanate, dimethyldiphenylmethane diisocyanate, tetramethyldiphenylmethane diisocyanate, 1,3- Phenylene diisocyanate, 1,4-phenylenedi isocyanate, m-xylylene diisocyanate, p-xylylene diisocyanate, o-xylylene diisocyanate and 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate and other aromatic diisocyanates,
Tetramethylene diisocyanate, hexamethylene diisocyanate, isopropylene diisocyanate, methylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate and other aliphatic diisocyanates,
Cyclohexane-1,4-diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, lysine diisocyanate, dicyclohexylmethane-4,4'-diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, methylcyclohexanediisocyanate, m-tetramethyl Preferable examples thereof include xylylene diisocyanate, diisocyanate obtained by converting the carboxyl group of dimer acid into an isocyanate group, and other alicyclic diisocyanates. These can be used alone or in admixture of two or more.

Of the above, from the viewpoint of reactivity and the like, from isophorone diisocyanate, 4,4'-diphenylmethane diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, tolylene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane-4,4'-diisocyanate. At least one of the chosen uses is preferred. It should be noted that these diisocyanates are also preferably triisocyanates which are trimers and have an isocyanurate structure.

(Polyol)
The polyurethane resin has a structural unit derived from a polyol, and the polyol is not particularly limited and is not limited to the following, but a polyether polyol, a polyester polyol, a polylactone polyol, a polycarbonate polyol and the like are preferably used. In addition, other dimer diols, hydrogenated dimer diols, castor oil-modified polyols and the like may be used. The polyurethane resin preferably has at least one structural unit selected from a polyether structural unit, a polyester structural unit and a polycarbonate structural unit, and more preferably contains a structural unit derived from a polyester polyol.

As the usage ratio of the polyol, it is preferable that the structural unit derived from the polyester polyol is contained in an amount of 5% by mass or more in the total mass of the structural units derived from the polyol. It is still more preferable to contain 10% by mass or more, and further preferably 30% by mass or more. In addition to the action of incorporating hydroxyic acid, which will be described later, into the polyurethane resin, it is possible to impart desorption by alkali, that is, the ability to desorb the desorbing layer and the pattern layer from the plastic base material with an alkaline aqueous solution, as well as the polyester polyol. In order to further improve the desorption property by alkaline hydrolysis of the ester bond site of the above, it is preferably contained in an amount of 45% by mass or more, and more preferably 60% by mass or more. It is more preferable to contain 70% by mass or more. Further, the total mass of the polyol preferably contains the structural unit derived from the polyether polyol in an amount of 55% by mass or less, and more preferably 35% by mass or less. It is also preferable that the content is 3% by mass or more.

The polyurethane resin preferably contains a structural unit derived from a polyether polyol and / or a structural unit derived from a polyester polyol. This is because the adhesion to the plastic base material and the printability are good. The polyether structural unit is preferably contained in an amount of 40% by mass or less, still more preferably 3 to 25% by mass, based on the total mass of the polyurethane resin. The polyester structural unit preferably contains 10 to 60% by mass, and more preferably 20 to 50% by mass. It is more preferably contained in an amount of 25 to 50% by mass.

The polyol used in the present invention preferably has a number average molecular weight of 500 to 10000. Here, the number average molecular weight used for the polyol is calculated from the hydroxyl value, and the hydroxyl value is calculated by esterifying or acetylating the hydroxyl group in the resin and back-dripping the remaining acid with an alkali in 1 g of the resin. The amount of hydroxyl groups is a value converted into the number of mg of potassium hydroxide, which is a value performed according to JIS K0070. When the number average molecular weight of the polyol is 10,000 or less, the blocking resistance to the plastic film is excellent. Further, when the number average molecular weight of the polyol is 500 or more, the flexibility of the polyurethane resin film is excellent and the adhesion to the plastic film is excellent. For the above reasons, the number average molecular weight is more preferably 1000 to 5000.

As the polyester polyol, for example, a polyester polyol which is a condensate of a dibasic acid and a diol is preferably mentioned. The dibasic acids include adipic acid, phthalic acid anhydride, isophthalic acid, terephthalic acid, maleic acid, fumaric acid, succinic acid, oxalic acid, malonic acid, pimelic acid, azelaic acid, sebacic acid, suberic acid, glutaric acid, 1 , 4-Cyclohexyldicarboxylic acid, dimer acid, hydrogenated dimer acid and the like are preferable, and adipic acid, succinic acid, sebacic acid and the like are preferable.
Examples of the diol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, 1,3-propanediol, 1,4-butanediol, 1,3-butanediol, 1,6-hexanediol, and 1,8-octanediol. , 1,9-Nonandiol, Neopentyl Glycol, 3-Methyl-1,5-Pentanediol, 2-Methyl-1,3-Propanediol, 3,3,5-trimethylpentanediol, 2,4-diethyl- 1,5-pentanediol, 1,12-octadecanediol, 1,2-alkanediol, 1,3-alkanediol, 1-monoglyceride, 2-monoglyceride, 1-monoglycerin ether, 2-monoglycerin ether, dimerdiol , Hydrophobic dimerdiol and the like are preferable. The polyester polyol can be used alone or in combination of two or more. Further, as a raw material for the polyester polyol, a polyol having 3 or more hydroxyl groups and a polyvalent carboxylic acid having 3 or more carboxyl groups can be used in combination.

Among these, as a preferable specific example, those containing a polyester-derived structural unit composed of adipic acid, succinic acid, sebacic acid and other dibasic acids and diols having a branched structure are preferable. This is because the adhesion to the plastic base material and the solubility of the ink composition can be improved. The diol having a branched structure is preferably a diol having a structure in which at least one hydrogen of the alkylene glycol is substituted with an alkyl group, and the diol having a branched structure is, for example, 1,2-propanediol. 1,3-Butanediol, 2-methyl-1,3-propanediol, neopentyl glycol, 1,4-pentanediol, 3-methyl-1,5-pentanediol, 2,5-hexanediol, 2-methyl -1,4-pentanediol, 2,4-diethyl-1,5-pentanediol, 2-butyl-2-ethyl-1,3-propanediol, 2-methyl-1,8-octanediol, 2,2 , 4-trimethyl-1,3-pentanediol, 2,2,4-trimethyl-1,6-hexanediol and the like are preferable. Of these, at least one selected from 1,2-propanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, and 2-butyl-2-ethyl-1,3-propanediol is preferable, and 1 The use of polyester polyols containing, 2-propanediol and / or 3-methyl-1,5-pentanediol is still preferred.

Preferred examples of the polyether polyol include polymers or copolymers such as methylene oxide, ethylene oxide, propylene oxide and tetrahydrofuran. These can be used alone or in admixture of two or more. More specifically, it preferably contains polyethylene glycol, polypropylene glycol, polytrimethylene glycol, polytetramethylene glycol and a copolymer composed of any of these, and may include polyethylene glycol, polypropylene glycol and polytetramethylene glycol. It is still preferable.

(Hydroxy acid)
Hydroxy acid refers to a compound having both a hydroxyl group, which is an active hydrogen group, and an acidic functional group in one molecule. The hydroxy acid is not particularly limited, but for example, dimethylolalkanoic acid such as 2,2-dimethylolpropionic acid, 2,2-dimethylolbutanoic acid, 2,2-dimethylolbutyric acid, and 2,2-dimethylolvaleric acid can be used. preferable. These can be used alone or in combination of two or more, and may be appropriately adjusted so that the acid value of the polyurethane resin is 15 to 70 mgKOH / g. The acid value is a value measured by JISK0070.

The acidic functional group in the present invention indicates a functional group that can be neutralized with potassium hydroxide when measuring the acid value, and specific examples thereof include a carboxyl group and a sulfonyl group, which are carboxyl groups. Is preferable. Since the acidic group has a high probability of not reacting with the isocyanate group in the process of synthesizing the polyurethane resin, the acid value can be maintained in the polyurethane resin.

Further, as described above, the polyurethane resin is a polyurethane resin obtained by further reacting a urethane prepolymer having an isocyanate group at the terminal formed by reacting a polyisocyanate, a polyol and a hydroxy acid with a polyamine (referred to as a chain extension reaction). Is preferable. In this case, in addition to the urethane bond, a urea bond is generated. As the polyisocyanate, polyol and hydroxy acid, the same embodiments as above are preferable.

(Polyamine)
Examples of the polyamine include, but are not limited to, ethylenediamine, propylenediamine, hexamethylenediamine, isophoronediamine, dicyclohexylmethane-4,4'-diamine, dimerdiamine obtained by converting the carboxyl group of dimer acid into an amino group, and the like. Diamines are preferred. These can be used alone or in admixture of two or more.
Amino acids can also be used for chain extension. The amino acid refers to a compound having both an amino group and an acidic functional group in one molecule, and preferred examples thereof include glutamine, asparagine, lysine, diaminopropionic acid, ornithine, diaminobenzoic acid and diaminobenzenesulfonic acid. Since the acidic group has a high probability of not reacting with the isocyanate group in the process of synthesizing the polyurethane resin, the acid value can be maintained in the polyurethane resin.

(Synthesis of polyurethane resin)
The method for synthesizing the polyurethane resin in the present invention will be described. The polyurethane resin in the present invention is formed by reacting a polyisocyanate, a polyol and a hydroxy acid (referred to as a urethanization step). The reaction ratio (NCO / OH) of the polyisocyanate to the polyol and the hydroxy acid is preferably 1.05 to 3.0, more preferably 1.1 to 2.8. The urethanization reaction step is preferably carried out at a temperature of 70 to 90 ° C. for 2 to 8 hours using an organic solvent inert to the isocyanate group, if necessary, and further using a catalyst if necessary. At this time, the polyisocyanate can be added dropwise at an appropriate rate while the polyol and the organic solvent are mixed and stirred. The stirring speed during the reaction is preferably that the reaction solutions are uniformly mixed, and that the stirring speed is appropriate and uniform rather than excessively slow stirring or possible fast stirring.

When the polyurethane resin is further subjected to a chain extension reaction with polyamine as a urethane prepolymer having an isocyanate group at the terminal obtained by the urethanization reaction step (referred to as a urea conversion reaction step), the solid content of the urethane prepolymer or polyamine is used. It is preferable to set it appropriately, and it is preferable to control the dropping rate relatively slowly. Since the viscosity of the dropping changes greatly in the reaction, it is preferable to set the stirring speed high in order to obtain a uniform reaction solution. The amino group / NCO, which is the ratio of the isocyanate group of the urethane prepolymer to the amino group of the polyamine, is preferably 0.7 to 1.3, and the reaction takes 1 to 8 hours at a temperature of 20 to 60 ° C. It is preferable that this is done.

(Polymerization inhibitor)
It is preferable to use a polymerization inhibitor for the purpose of preventing a high molecular weight or a non-uniform reaction due to an excessive reaction. As the polymerization terminator, monoalcohol or monoamine is preferably used in the case of a polyurethane resin that can be produced only by the urethanization step, and monoamine is used in the case of a polyurethane resin that is produced by performing a urea conversion reaction step in addition to the urethanization step. It is preferable to do so.
As the monoalcohol, substituted or unsubstituted alcohol is preferable, and methanol, ethanol, n-propanol, isopropyl alcohol, 1-butanol, and the like are preferable. As the monoamine, substituted or unsubstituted monoamine is preferable, and n-butylamine, n-dibutylamine, octylamine, diethylamine, monoethanolamine, monopropanolamine, diethanolamine, dipropanolamine and the like are preferable.

(Other resins)
In the present invention, the binder resin is also suitable when other resins are used in combination in addition to the above polyurethane resin, and examples thereof are not limited to the following, but all of cellulose-based resins, polyamide resins, and vinyl chloride-vinyl acetate are used. Vinyl chloride resin such as polymer resin, vinyl chloride-acrylic copolymer resin, rosin resin, ethylene-vinyl acetate copolymer resin, vinyl acetate resin, acrylic resin, styrene resin, dammar resin, styrene-maleic acid copolymer Examples thereof include resins, polyester resins, alkyd resins, terpene resins, phenol-modified terpene resins, ketone resins, cyclized rubbers, rubber chlorides, butyral, polyacetal resins, petroleum resins, and modified resins thereof. These resins can be used alone or in admixture of two or more. Above all, it is preferable to use at least one selected from the group consisting of vinyl chloride resin, acrylic resin and cellulosic resin. It is still more preferable to use a vinyl chloride resin and / or a cellulosic resin. The ratio of the polyurethane resin to the combined resin is more preferably 95: 5 to 50:50 for the former: the latter. This is because the detached pattern layer and the like can be easily collected. When an acrylic resin is used in combination, it is preferably an acrylic resin having an acid value of 20 to 70 mgKOH / g.

<Organic solvent>
The organic solvent-based printing ink of the present invention contains an organic solvent. Examples of the organic solvent used include, but are not limited to, aromatic organic solvents such as toluene and xylene, ketone organic solvents such as methyl ethyl ketone and methyl isobutyl ketone, ethyl acetate, n-propyl acetate and isopropyl acetate. Known organic solvents such as isobutyl acetate, ester organic solvent, methanol, ethanol, n-propanol, isopropanol, n-butanol and other alcohol-based organic solvents, ethylene glycol monopropyl ether and propylene glycol monomethyl ether and other glycol ether-based solvents. It can be used, and it is preferable to mix and use it. Among them, an organic solvent (non-toluene-based organic solvent) that does not contain aromatic organic solvents such as toluene and xylene is preferable because the stability of the gravure ink with time is good when it contains a hydrocarbon-based wax, and a ketone-based organic solvent is preferable. Is more preferable, and it is more preferable to contain an ester-based organic solvent and an alcohol-based organic solvent. When the ester-based organic solvent and the alcohol-based organic solvent are contained, a mixed organic solvent containing an ester-based organic solvent: alcohol-based organic solvent at a mass ratio of 90:10 to 40:60 is more preferable. Further, the glycol ether-based organic solvent may be contained in an amount of 5% by mass or less in 100% by mass of the ink.

<Additives>
The organic solvent-based printing ink of the present invention can appropriately contain conventionally known additives, and in the production of gravure ink, additives such as pigment derivatives, dispersants, wetting agents, and adhesive aids are used as necessary. , Leveling agent, defoaming agent, antistatic agent, viscosity modifier, metal chelate, trapping agent, blocking inhibitor, wax component other than the above, isocyanate-based curing agent, silane coupling agent and the like can be used.

<Organic solvent-based printing ink>
The organic solvent-based printing ink of the present invention includes a form of a clear ink or a color ink. However, the form further containing an organic solvent, other inks, etc. is not excluded as long as the gist of the present invention is not changed.

<Clear ink>
The clear ink means a form in which the ink or the printing layer is approximately cloudy or colorless / transparent, and does not exclude slight coloring caused by the binder resin, extender pigment, additives, or the like. The solid content of the clear ink in the total mass of the ink is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass. Further, the binder resin is preferably contained in the total mass of the ink in an amount of 0.5 to 50% by mass as a solid content, and more preferably 5 to 30% by mass. Within the above range, the viscosity of the clear ink becomes appropriate, and when the ink is applied to the plastic film by any printing method, the printability such as halftone dot reproducibility becomes good. The "solid content" means the total mass% of the non-volatile components.

(Constitution pigment)
The clear ink preferably contains an extender pigment. As the extender pigment, silica, barium sulfate, kaolin, clay, calcium carbonate, magnesium carbonate and the like are preferable. These are used to improve fluidity, film strength and optical properties. Above all, the use of silica is preferable, and it is preferable that it is hydrophilic. The extender pigment preferably has an average particle size of 0.5 to 10 μm, and more preferably 1 to 8 μm. The extender pigment is preferably contained in an amount of 0.5 to 10% by mass, more preferably 1 to 5% by mass, in the total mass of the ink. This is because the wettability of the pattern ink becomes good when the pattern ink is overprinted.

<Color ink>
The color ink refers to an organic solvent-based printing ink containing a colorant, and does not include the above-mentioned clear ink. The colorant component is preferably a color dye and / or a color pigment. The solid content of the color ink in the total mass of the ink is preferably 5 to 50% by mass, and more preferably 10 to 40% by mass. The colorant is preferably contained in an amount sufficient to secure the concentration and coloring power of the ink, that is, 1 to 50% by mass in the total mass of the ink, and more preferably 3 to 15% by mass. The binder resin preferably contains 0.5 to 50% by mass in solid content in the total mass of the ink, and more preferably 5 to 30% by mass. Within the above range, the viscosity of the color ink becomes appropriate, and when the ink is applied to the plastic film by any printing method, the printability such as halftone dot reproducibility becomes good. As the color ink, an extender pigment may be used as an auxiliary, and the extender pigment is preferably the same as in the case of the above clear ink.

(Coloring Pigment) The colorant is preferably a pigment, and the mass ratio of the binder resin to the color pigment (binder resin / pigment) is preferably 99/1 to 10/90. Further, it is more preferably 80/20 to 20/80. The coloring pigment is preferably an organic pigment or an inorganic pigment, and the inorganic pigment preferably contains titanium oxide, and the organic pigment preferably consists of an organic compound or an organic metal complex.

Among the coloring pigments, the organic pigments are not limited to the following examples, but are soluble azo type, insoluble azo type, azo type, phthalocyanine type, halogenated phthalocyanine type, anthraquinone type, ansanthron type, dianthraquinonyl type, and anthra. Pyrimidine, perylene, perinone, quinacridone, thioindigo, dioxazine, isoindolenone, quinophthalone, azomethinazo, flavanthrone, diketopyrrolopyrrole, isoindoline, indancelon, carbon black Pigments such as system can be mentioned. Also, for example, Carmin 6B, Lake Red C, Permanent Red 2B, Disazo Yellow, Pyrazolon Orange, Carmin FB, Chromophthal Yellow, Chromophthal Red, Phthalocyanine Blue, Phthalocyanine Green, Dioxazine Violet, Quinacridone Magenta, Quinacridone Red, Indance. Examples thereof include lonblue, pyrimidine yellow, thioindigo bordeaux, thioindigo magenta, perylene red, perinone orange, isoindolinone yellow, aniline black, diketopyrrolopyrrole red, and daylight fluorescent pigment.

Among the coloring pigments, examples of the inorganic pigments include white inorganic pigments such as titanium oxide, zinc oxide, zinc sulfide, and chromium oxide. Among the inorganic pigments, the use of titanium oxide is particularly preferable. Titanium oxide has a white color and is preferable from the viewpoints of coloring power, hiding power, chemical resistance and weather resistance, and from the viewpoint of printing performance, the titanium oxide is preferably treated with silica and / or alumina.

Among the coloring pigments, inorganic pigments other than white include, for example, aluminum particles, mica (mica), bronze powder, chrome vermillion, chrome yellow, cadmium yellow, cadmium red, ultramarine, dark blue, red iron oxide, yellow iron oxide, and iron black. , Titanium oxide, zinc oxide and the like, and aluminum is in the form of powder or paste, but it is preferable to use it in the form of paste from the viewpoint of handleability and safety, and it may be either a leaving type or a non-leaving type.

<Manufacturing of organic solvent-based printing ink>
The organic solvent-based printing ink of the present invention can be produced by dissolving and / or dispersing a binder resin, an extender pigment, a coloring pigment, or the like in a liquid medium. For example, a pigment, a polyurethane resin, a binder resin such as vinyl chloride-vinyl acetate copolymer resin, silica particles and an organic solvent as needed are dispersed, and a polyurethane resin and an organic solvent as needed are used in the pigment dispersion. Organic solvent-based printing inks can be manufactured by blending other resins and additives. The viscosity and color of the organic solvent-based printing ink can be adjusted by appropriately adjusting the size of the crushed media of the disperser, the filling rate of the crushed media, the dispersion treatment time, the ejection speed of the pigment dispersion, the viscosity of the pigment dispersion, and the like. , Can be adjusted. As the disperser, generally used, for example, a roller mill, a ball mill, a pebble mill, an attritor, a sand mill and the like can be used. It is preferably manufactured using a sand mill.

The viscosity of the organic solvent-based printing ink of the present invention is preferably in the range of 20 to 500 mPa · s, and more preferably 30 to 300 mPa · s. This is because appropriate printability can be obtained in the printing process. The viscosity of the printing ink can be adjusted by adjusting the amount of the polyurethane resin or other binder resin, the amount of the organic solvent, and the dispersion conditions of the pigment.

(Picture ink) The picture ink refers to a printing ink that does not have the above-mentioned desorption function, and preferably includes screen ink, gravure ink, flexo ink, inkjet ink, offset ink, and other printing inks. 2005-298618, 2006-299136, 2009-249388, 2013-127038, 2017-19991, 2006-131844, 2013- The printing inks described in JP-A-40248, JP-A-2007-231148, JP-A-2006-257302 and the like can be preferably used. However, it is not limited to these. Of these, the use of gravure ink, flexo ink, and inkjet ink is preferable, and the use of gravure ink and / or flexo ink is still preferable.

<Printing of organic solvent-based printing ink>
As a printing method for the organic solvent-based printing ink, a printing method such as screen printing, offset printing, flexo printing, dry offset printing, gravure printing, and inkjet printing can be preferably used. Of these, gravure printing or flexographic printing is still preferable.

<Gravure printing>
(Gravure version)
In the present invention, the gravure plate is a metal cylindrical one, and recesses are created in each color by engraving, corrosion, or laser. There are no restrictions on the use of engraving and laser, and it can be set arbitrarily according to the pattern. As the number of lines, 100 to 300 lines are appropriately used, and the larger the number of lines, the finer the printing is possible. The thickness of the print layer is preferably 0.1 μm to 100 μm.
(Printer)
In a gravure printing machine, one printing unit includes the above gravure plate and a doctor blade. There are many printing units, and printing units corresponding to organic solvent-based printing inks and pattern inks can be set, and each unit has an oven drying unit. Printing is performed by rolling, and it is a take-up printing method. The type of plate and the type of doctor blade are appropriately selected, and the one according to the specifications can be selected.

<Flexographic printing>
(Flexographic version)
Examples of the plate used for flexographic printing in the present invention include a photosensitive resin plate that utilizes ultraviolet curing by a UV light source and an elastomer material plate that uses a direct laser engraving method. Regardless of the method of forming the image portion of the flexographic plate, a plate having a screening line number of 75 lpi or more is used. Any sleeve or cushion tape can be used to attach the plate.
(Printer)
The flexo printing machine includes a CI type multicolor flexo printing machine, a unit type multicolor flexo printing machine, etc., and the ink supply method can be a chamber method or a two-roll method, and an appropriate printing machine can be used. can.

<Printed matter and laminate>
The form of the printed matter and the laminate in the present invention is not limited, but the following aspects are preferably mentioned.
-Base material 1 / desorption layer (clear) / pattern layer-base material 1 / desorption layer (color) / pattern layer-base material 1 / desorption layer (clear) / adhesive layer / base material 2
-Base material 1 / Desorption layer (color) / Adhesive layer / Base material 2
-Base material 1 / Desorption layer (clear) / Pattern layer / Adhesive layer / Base material 2
-Base material 1 / desorption layer (color) / pattern layer / adhesive layer / base material 2-Picture layer / desorption layer (clear) / base material 1 / adhesive layer / base material 2
-Picture layer / Desorption layer (color) / Base material 1 / Adhesive layer / Base material 2
-Base material 1 / desorption layer (clear) / pattern layer / desorption layer (clear) / adhesive layer / base material 2
-Base material 1 / Desorption layer (color) / Pattern layer / Desorption layer (color) / Adhesive layer / Base material 2
In the above, "clear" means clear ink, and "color" means color ink.

<Base material 1>
Examples of the base material to which the organic solvent-based printing ink of the present invention can be applied include polyethylene, polypropylene and other polyolefin base materials, polycarbonate base materials, polyethylene terephthalate, polyvinylidene and other polyester base materials, polystyrene base materials, AS resin or ABS resin and the like. Polystyrene resin, polyamide base material, polyvinyl chloride base material, various base materials of polyvinylidene chloride, cellophane base material, paper base material, aluminum foil base material, etc., or a film or sheet made of a composite material thereof. There is a thing. Of these, polyester base materials and polyamide base materials having a high glass transition temperature are preferably used.

The surface of the substrate may be coated with a metal oxide or the like by vapor deposition coating and / or a coating treatment such as polyvinyl alcohol. For example, GL-manufactured by Toppan Printing Co., Ltd., in which aluminum oxide is vapor-deposited on the surface of the substrate Examples include AE and IB-PET-PXB manufactured by Dai Nippon Printing Co., Ltd. Further, if necessary, those treated with additives such as antistatic agents and ultraviolet antioxidants, and those treated with corona treatment or low temperature plasma treatment on the surface of the base material can also be used.

<Base material 2>
The base material 2 may be the same as the base material 1, and may be the same or different. It is preferably a thermoplastic base material (sometimes referred to as a sealant), and a non-stretched polyethylene base material, a non-stretched polypropylene base material, a non-stretched polyester base material, or the like is preferable.

<Adhesive layer>
In order to bond the base material 1 and the base material 2, a laminating process using an adhesive is required. Typical examples of the laminating process include an extrusion laminating method, a dry laminating method, and a non-solvent laminating method. The laminating process is a method in which an adhesive layer is provided on any surface of a printed matter by coating, drying, or the like, and further thermocompression-bonded to the base material 2 for laminating.
The adhesive layer is not limited to the following, but preferably includes an anchoring agent layer, a molten resin layer, a urethane-based adhesive layer, an acrylic-based adhesive layer, and the like, and can be obtained by a melt extrusion method, a coating method, or the like. For example, as the urethane-based adhesive, a two-component adhesive composed of a mixture of a polyol and an isocyanate curing agent is suitable, and examples of the polyol include polyester-based adhesives and polyether-based adhesives. Specific examples thereof include TM-250HV / CAT-RT86L-60, TM-550 / CAT-RT37, TM-314 / CAT-14B manufactured by Toyo Morton Co., Ltd.

(Desorption process)
In order to remove (remove) the desorbed layer or the like from the printed matter, it is immersed in the above-mentioned alkaline aqueous solution. As a condition for removing the desorbed layer, the pattern layer and other layers for removing the desorbed layer and the like in the present invention, the concentration of the alkaline aqueous solution is preferably 0.5 to 15% by mass, preferably 1 to 5% by mass. Is still preferable. When the concentration is within the above range, the alkaline aqueous solution can maintain sufficient alkalinity for desorption, and is also suitable for penetrating from the cross section of the printed matter and the laminated laminate and being compatible with the desorbed layer. , The ink can be removed in a shorter time. Moreover, it is preferable that the concentration of the alkaline aqueous solution is 5% or less from the viewpoint of environmental friendliness and handling of waste liquid in the recycling process. The immersion temperature is preferably room temperature to 90 ° C, more preferably 30 to 70 ° C. The soaking time is 1 minute to 24 hours, more preferably 1 minute to 12 hours. The removal rate of the printed layer after washing and drying with water is preferably 90% or more, more preferably 95% or more, still more preferably 98% or more.
In the case of the front printing form, the concentration of the alkaline aqueous solution is preferably 0.5 to 15% by mass, the immersion temperature is preferably 30 to 70 ° C., and the immersion time is 1 to 12 hours. preferable. In the back printing (laminated form), the concentration of the alkaline aqueous solution is preferably 1 to 15% by mass, the immersion temperature is preferably 30 to 70 ° C., and the immersion time is preferably 1 to 12 hours.

The amount of the alkaline aqueous solution used is preferably 1 to 1 million times the mass of the printed matter or the laminate. Further, in order to improve efficiency, a circulation type rinse, a printed matter or a laminate may be crushed and stirred.

With the printed matter of the present invention, the printed layer can be removed in an alkaline aqueous solution, washed with water and dried to obtain a recycled polyester base material. Further, the recycled polyester base material can be recycled into pellets by an extruder and used.

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. Unless otherwise specified, parts and% in the present invention represent parts by mass and% by mass.

(Molecular weight and molecular weight distribution)
For the weight average molecular weight (Mw), the number average molecular weight (Mn), and the molecular weight distribution (Mw / Mn), GPC (gel permeation chromatography) "Shodex GPC System-21" manufactured by Showa Denko KK was used. GPC is a liquid chromatography in which substances dissolved in a solvent are separated and quantified by the difference in their molecular sizes, and the determination of tetrohydrofuran, Mw, Mw and Mw / Mn as solvents was performed in terms of polystyrene.
(Acid value)
In the following, the acid value was measured according to the method described in JIS K0070 (1992).

[Synthesis Example 1] (Creation of P1)
124.1 parts of PPG2000 (polypropylene glycol with a number average molecular weight of 2000), PMPA2000 (number average) while introducing nitrogen gas in a reactor equipped with a reflux condenser, a dropping funnel, a gas introduction tube, a stirrer, and a thermometer. 3 parts of poly (3-methyl-1,5-pentaneadipate) diol with a molecular weight of 2000, 24.6 parts of 2,2-dimethylolbutanoic acid (DMBA), 111.2 parts of isophorone diisocyanate (IPDI), methyl ethyl ketone (MEK) ) 200 parts were charged and reacted at 90 ° C. for 5 hours to obtain a resin solution of a terminal isocyanate group prepolymer. 60 parts of the obtained terminal isocyanate group prepolymer mixed with 33.6 parts of isophorone diamine (IPDA), 3.5 parts of di-n-butylamine (DBA) and 350 parts of isopropyl alcohol (IPA) at room temperature. The mixture was added dropwise over a minute and further reacted at 70 ° C. for 3 hours. Further, the solid content was adjusted using 150 parts of MEK.
A polyurethane resin (P1) solution having a solid content of 30%, a weight average molecular weight of 35,000, Mw / Mn = 3, and an acid value of 31.1 mgKOH / g was obtained.

[Synthesis Examples 2 to 13] (Creation of P2 to P13)
Polyurethane resins (P2 to P13) were obtained by the same operation as in Synthesis Example 1 except that the raw materials and the charging ratios shown in Table 1 were used. Properties such as Mw, Mw / Mn and acid value are shown in Table 2. For P2 to P4 and P7, the dropping time of polyamine or the like was adjusted so that Mw / Mn had the values shown in Table 2. The abbreviations of the raw material compounds shown in Table 1 are shown below.
PEG2000: Polyethylene glycol with a number average molecular weight of 2000 PPA2000: Poly (propylene glycol) adipatediol with a number average molecular weight of 2000

[Synthesis Example 14] (Creation of P14)
63 parts of PPG2000, 148.9 parts of PMPA2000, 23.5 parts of DMBA, while introducing nitrogen gas in a reactor equipped with a reflux condenser, a dropping funnel, a gas introduction tube, a stirrer, and a thermometer. 64.6 parts of IPDI and 200 parts of MEK were charged and reacted at 90 ° C. for 5 hours to obtain a resin solution of a terminal isocyanate-based prepolymer. A mixture of 350 parts of IPA and 150 parts of MEK was added to the obtained terminal isocyanate group prepolymer, and the mixture was reacted at 70 ° C. for 3 hours to have a solid content of 30%, a mass average molecular weight of 20000, Mw / Mn = 3, and an acid value. A 29.7 mgKOH / g polyurethane resin (P14) solution was obtained.

[Synthesis Example 15] (Creation of P15)
A polyurethane resin (P15) solution was obtained by the same operation as in Synthesis Example 14 except that the raw materials and the charging ratios shown in Table 1 were used.

[Comparative synthesis example 1] (Preparation of PP1)
While introducing nitrogen gas in a reactor equipped with a reflux condenser, a dropping funnel, a gas introduction tube, a stirrer, and a thermometer, 73.6 parts of PEG2000, 70.3 parts of PMPA2000, and 31.6 parts of DMBA. 101.2 parts of IPDI and 200 parts of MEK were charged and reacted at 90 ° C. for 5 hours to obtain a resin solution of a terminal isocyanate-based prepolymer. A mixture of 23.3 parts of IPDA and 150 parts of IPA was added dropwise to the obtained terminal isocyanate-based prepolymer over 60 minutes at room temperature, and then 10.0 parts of 28% ammonia water and 690 parts of ion-exchanged water were added. It is solubilized by gradually adding it to the solvent-type polyurethane resin solution and neutralizing it, and further, MEK and IPA are distilled off under reduced pressure. The acid value is 39.9 mgKOH / g, the weight average molecular weight is 35,000, and the solid content is 30. % Aqueous aqueous polyurethane resin (PP1) solution was obtained. However, the acid value in PP1 is a value before neutralization.

[Comparative synthesis example 2] (Preparation of PP2)
41.3 parts of PPG2000, 39.4 parts of PMPA2000, 59.0 parts of DMBA while introducing nitrogen gas in a reactor equipped with a reflux condenser, a dropping funnel, a gas introduction tube, a stirrer, and a thermometer. 136.4 parts of IPDI and 200 parts of MEK were charged and reacted at 90 ° C. for 5 hours to obtain a resin solution of a terminal isocyanate-based prepolymer. A mixture of 21.7 parts of IPDA, 2.2 parts of DBA and 350 parts of IPA was added to the obtained terminal isocyanate group prepolymer, and the mixture was further reacted at 70 ° C. for 3 hours. Further, the solid content was adjusted with 150 parts of MEK.
A polyurethane resin (PP2) solution having a solid content of 30%, a mass average molecular weight of 35,000, Mw / Mn = 3.4, and an acid value of 74.5 mgKOH / g was obtained.

[Comparative synthesis example 3] (Preparation of PP3)
A polyurethane resin (PP3) solution was obtained by the same operation as in Comparative Synthesis Example 2 except that the raw materials and the charging ratios shown in Table 1 were used.

The composition of the polyurethane resin at the time of synthesis is shown in Table 1-1, and the characteristic values of the obtained polyurethane resin are shown in Table 1-2.

(Example 1: Preparation of clear ink S1)
87 parts of polyurethane resin solution P1 (solid content 25%), 5 parts of ethyl acetate (EA), 5 parts of IPA, and 3 parts of silica (hydrophilic silica particles P-73 with an average particle diameter of 3.8 μm manufactured by Mizusawa Chemical Co., Ltd.). The mixture was stirred and mixed using a disper to obtain clear ink S1.

[Examples 2 to 19] (Preparation of clear inks S2 to S19)
Organic solvent-based printing inks S2 to S19 were obtained by the same method as in Example 1 using the raw materials shown in Table 2 at the blending ratios described.
The abbreviations of the raw material compounds shown in Table 2 are shown below.
Vinyl chloride resin: Vinyl chloride-vinyl acetate copolymer resin (vinyl chloride: vinyl acetate: vinyl alcohol = 88: 1: 11) (30% solid content solution)
Acrylic resin: Styrene-acrylic copolymer resin (30% solid content solution) with a weight average molecular weight of 40,000 and an acid value of 60 mgKOH / g.

(Example 20: Creation of color ink S20)
10 parts of copper phthalocyanine indigo (phthalocyanine LIONOL BLUE FG-7358-G manufactured by Toyo Color Co., Ltd.), 40 parts of polyurethane resin (P10), 3 parts of ethyl acetate and 3 parts of IPA were stirred and mixed, and then the pigment was dispersed in a sand mill for 20 minutes. Further, 40 parts of the polyurethane resin solution (P10), 2 parts of ethyl acetate and 2 parts of IPA were stirred and mixed to obtain an indigo printing ink (S20). The total value is shown for each component shown in Table 2.

(Example 21: Preparation of color ink S21)
The organic solvent-based printing ink S21 was obtained by the same method as in Example 20 using the raw materials shown in Table 2 at the blending ratios described.

(Comparative Examples 1 to 5) (Creation of SS1 to 5)
Inks SS1 to 5 were obtained by the same method as in Example 1 except that the raw materials shown in Table 2 were used in the blending ratios described.

<Creation of printed matter using S1>
(Print composition A: PET substrate / desorption layer / pattern layer)
Clear ink S1 was diluted with ethyl acetate / IPA mixed solvent (mass ratio 70/30) to Zahn Cup # 3 (manufactured by Rigosha) for 15 seconds (25 ° C.). Then, a clear ink S1 and PANNECO AM 92 ink (organic solvent-based gravure ink manufactured by Toyo Ink Co., Ltd.) were provided on a corona-treated polyethylene terephthalate (PET) substrate (thickness 12 μm), and a gravure plate having a plate depth of 35 μm was provided. Printing was performed in this order on a gravure printing machine and dried at 50 ° C. to obtain a printed matter as a PET substrate / desorption layer (S1) / pattern layer.

<Creation of printed matter using S2 to S21 and printed matter using SS1 to SS5>
The printing inks (S2 to S21) obtained in Examples 2 to 21 and the printing inks (SS1 to SS5) obtained in Comparative Examples 1 to 5 are also printed matter having the same printing configuration by the same procedure as described above. It was created.

<Creation of laminated laminate using S1>
(Laminate structure A: OPP base material / desorption layer / pattern layer / adhesive layer / VMCPP base material)
Clear ink S1 was diluted with ethyl acetate / IPA mixed solvent (mass ratio 70/30) to Zahn Cup # 3 (manufactured by Rigosha) for 15 seconds (25 ° C.). After that, clear ink S1 and Rio Alpha S R92 ink (organic solvent-based gravure ink manufactured by Toyo Ink Co., Ltd.) were applied to the corona-treated OPP film (thickness 20 μm), and two gravure calibration colors equipped with a gravure plate with a plate depth of 35 μm. Printing was performed in this order on a machine, and each unit was dried at 50 ° C. to obtain a printed matter having an OPP substrate / desorption layer (S1) / pattern layer in this order.
Using a dry laminating machine, a dry laminating adhesive (TM-340V / CAT-29B manufactured by Toyo Morton Co., Ltd.) was applied onto the pattern layer of this printed matter, and VMCPP (aluminum vapor deposition non-stretching) was applied at a line speed of 40 m / min. It was laminated with a polypropylene film (thickness 25 μm) to obtain a laminated laminate in the order of OPP base material / desorption layer (S1) / pattern layer / adhesive layer / VMCPP base material.

<Preparation of laminated laminate using S2 to S21 and SS1 to SS5>
When the printing inks (S2 to S21) obtained in Examples 2 to 21 and the printing inks (SS1 to SS5) obtained in Comparative Examples 1 to 5 are used, the same laminating is performed in the same procedure as above. Laminated laminates using S2 to S21 and SS1 to SS5 having a structure were prepared.

<Creation of packaging bag using S1>
(Laminate structure B: PET base material / desorption layer / pattern layer / adhesive layer / CPP base material)
Clear ink S1 was diluted with ethyl acetate / IPA mixed solvent (mass ratio 70/30) to Zahn Cup # 3 (manufactured by Rigosha) for 15 seconds (25 ° C.). After that, clear ink S1 and Rio Alpha S R92 ink (manufactured by Toyo Ink Co., Ltd.) were applied to the corona-treated PET substrate (thickness 12 μm) with a gravure calibration two-color machine equipped with a gravure plate with a plate depth of 35 μm. Printing was performed in order, and each unit was dried at 50 ° C. to obtain a printed matter having a PET substrate / desorption layer (S1) / pattern layer in this order.
Using a dry laminating machine, a dry laminating adhesive (TM-250HV / CAT-RT86L-60 manufactured by Toyo Morton Co., Ltd.) was applied onto the pattern layer of this printed matter, and CPP (unstretched polypropylene) was applied at a line speed of 40 m / min. It was laminated with a base material having a thickness of 30 μm) to obtain a laminated laminate in the order of PET base material / desorption layer (S1) / pattern layer / adhesive layer / CPP. The laminated laminate was cut into 15 cm × 25 cm, and the edge portion was thermocompression bonded (called heat seal) at 180 ° C. to obtain each packaging bag.

<Creation of packaging bags using S2-S21 and SS1-SS5>
When the printing inks (S2 to S21) obtained in Examples 2 to 21 and the printing inks (SS1 to SS5) obtained in Comparative Examples 1 to 5 are used, the same laminating is performed by the same procedure as described above. A packaging bag using S2 to S21 and SS1 to SS5 having a structure was prepared.

<Characteristic evaluation>
The evaluations described below were carried out using the organic solvent-based printing inks S1 to S21 (Examples), SS1 to SS5 (Comparative Examples) obtained above, their printed matter, laminated laminates, and packaging bags.

<Evaluation of detachability in printed matter>
The printed matter of print configuration A prepared in the above Examples and Comparative Examples was cut into 4 cm × 4 cm, immersed in 50 g of a 2% sodium hydroxide (NaOH) aqueous solution, stirred at 70 ° C., washed with water and dried, and then PET. The peelability of the pattern layer from the substrate was evaluated.
5 (excellent): The print layer such as the pattern layer peels off from the 100% PET film within 20 minutes of stirring 4 (Good): The print layer such as the pattern layer peels off from the 100% PET film within 1 hour over 20 minutes of stirring 3 (Good) Possible): 80% or more and 100% or less of the print layer such as the pattern layer is peeled off from the PET film within 12 hours over 1 hour of stirring. Peeled from PET film.
1 (inferior): Less than 20% of the print layer such as the pattern layer is peeled off from the PET film after 12 hours of stirring.
3, 4 and 5 are ranges in which there is no practical problem.

<Evaluation of detachability in laminated laminate>
The laminated laminate of Laminated Structure A prepared in the above Examples and Comparative Examples was cut into 4 cm × 4 cm, immersed in 50 g of a 2% sodium hydroxide (NaOH) aqueous solution, stirred at 70 ° C., washed with water and dried. Later, the peelability of the pattern layer from the PET film was evaluated.
5 (excellent): The print layer such as the pattern layer peels off from the 100% PET film within 20 minutes of stirring 4 (Good): The print layer such as the pattern layer peels off from the 100% PET film within 1 hour over 20 minutes of stirring 3 (Good) Possible): 80% or more and 100% or less of the print layer such as the pattern layer is peeled off from the PET film within 12 hours over 1 hour of stirring. Peeled from PET film.
1 (inferior): Less than 20% of the print layer such as the pattern layer is peeled off from the PET film after 12 hours of stirring.
3, 4 and 5 are ranges in which there is no practical problem.
<Retort resistance evaluation>
The packaging bag of the laminated structure B prepared in the above Examples and Comparative Examples was subjected to a retort test at 120 ° C. for 80 minutes, and the laminated strength immediately after the retort and the laminated strength before the retort were compared and evaluated.
5 (excellent): No decrease in laminate strength was observed before and after the retort, and the laminate strength immediately after the retort was 1.0 N / 15 mm or more. Although it can be seen, the laminate strength immediately after retort is 1.0 N / 15 mm or more 3 (possible): The laminate strength is decreased by 1.0 N / 15 mm or more before and after the retort, but the laminate strength immediately after retort is 1.0 N. / 15 mm or more 2 (impossible): A decrease in laminate strength of 1.0 N / 15 mm or more was observed before and after the retort, and the laminate strength immediately after the retort was 0.5 N / 15 mm or more and less than 1.0 N / 15 mm 1 ( Inferior): A decrease in laminate strength of 1.0 N / 15 mm or more was observed before and after the retort, and those having a laminate strength of less than 0.5 N / 15 mm immediately after the retort 3, 4 and 5 are in the range where there is no practical problem.

<Evaluation of dryness>
On a corona-treated PET film (thickness 12 μm) at a temperature of 25 ° C., bar coater No. The organic solvent-based printing inks S1 to S21 (Example) and SS1 to SS5 (Comparative Example) were applied using No. 4. Immediately after coating, the finger was touched every 5 seconds, and the time when the stickiness (called tack) disappeared was set as the end point of drying, and the drying property was evaluated. The bar coater is Miyabar No. 1 manufactured by Daiichi Rika Co., Ltd. 4 was used.
5 (excellent): Dry in less than 15 seconds.
4 (Good): Dry in 15 seconds or more and less than 30 seconds.
3 (possible): Dry in 30 seconds or more and less than 45 seconds.
2 (impossible): Dry in 45 seconds or more and less than 60 seconds.
1 (inferior): Dry in 60 seconds or more.
3, 4 and 5 are ranges in which there is no practical problem.

<Example 22>
In the above evaluation, the color ink S20 was used, and the printed matter of the print structure A, the laminated laminate of the laminated structure A, and the packaging bag of the laminated structure B were prepared by the same method except that the pattern layer was not used. The print configuration and the laminated configuration are shown below.
(Printed matter printing configuration)
PET substrate / desorption layer (S20)
(Laminated structure of laminated laminate)
OPP base material / desorption layer (S20) / adhesive layer / VMCPP base material (laminated structure of packaging bag)
When the same characteristic evaluation as above was performed using each of the PET base material / desorption layer (S20) / adhesive layer / CPP base material, the desorption property evaluation in the printed matter on the front print: 3, the desorption in the laminated laminate. The release evaluation was 3, the retort resistance evaluation was 5, and the dryness evaluation was 5.

<Example 23>
In the above evaluation, the color ink S21 was used to prepare a printed matter, a laminated laminate, and a packaging bag having the print configuration and the laminated configuration described below by the same method as in Example 22.
(Printed matter printing configuration)
PET substrate / desorption layer (S21)
(Laminated structure of laminated laminate)
OPP base material / desorption layer (S21) / adhesive layer / VMCPP base material (laminated structure of packaging bag)
When the same characteristic evaluation as above was performed using each of the PET base material / desorption layer (S21) / adhesive layer / CPP base material, the desorption property evaluation in the printed matter on the front print: 3, the desorption in the laminated laminate. The release evaluation was 3, the retort resistance evaluation was 5, and the dryness evaluation was 5.

From the above evaluation results, the organic solvent-based printing ink of the present invention has good print processing suitability, and the ink and the like are desorbed from the plastic film by the alkaline aqueous solution in the laminate in the front print configuration and the laminate configuration. It was shown that it can be used and that it exhibits good retort suitability in a laminated structure.

Claims (7)

A substrate recycling method in which a printed matter having a substrate 1, a desorbing layer, and a pattern layer in this order is immersed in an alkaline aqueous solution to peel off the pattern layer to recycle the substrate 1.
The desorbed layer is formed of an organic solvent-based clear ink or a color ink, and is formed from an organic solvent-based clear ink or a color ink.
The clear ink or color ink contains a polyurethane resin having an acid value of 15 to 70 mgKOH / g and a molecular weight distribution (Mw / Mn) of 1.2 or more and 6 or less as a binder resin.
The temperature of the alkaline aqueous solution is room temperature to 90 ° C.
Then, a base material recycling method including washing with water and a drying step. A laminate having the base material 1, the desorbed layer, the pattern layer and the base material 2 in this order (however, having the desorbed layer in the cross section) is immersed in an alkaline aqueous solution to peel off the pattern layer and the base material 2. This is a base material recycling method that recycles the base material 1.
The desorbed layer is formed of an organic solvent-based clear ink or a color ink, and is formed from an organic solvent-based clear ink or a color ink.
The clear ink or color ink contains a polyurethane resin having an acid value of 15 to 70 mgKOH / g and a molecular weight distribution (Mw / Mn) of 1.2 or more and 6 or less as a binder resin.
The temperature of the alkaline aqueous solution is room temperature to 90 ° C.
Then, a base material recycling method including washing with water and a drying step. The substrate recycling method according to claim 1 or 2, wherein the polyurethane resin has a weight average molecular weight of 10,000 to 100,000. The substrate recycling method according to any one of claims 1 to 3 , wherein the polyurethane resin contains a structural unit derived from a polyol and contains 5% by mass or more of the structural unit derived from a polyester polyol in the total mass of the structural unit. The substrate recycling method according to any one of claims 1 to 4, wherein the polyurethane resin contains a structural unit derived from polyester composed of a dibasic acid and a diol having a branched structure. The substrate recycling method according to any one of claims 1 to 5, wherein the polyurethane resin has an acid value of 20 to 50 mgKOH / g. The organic solvent-based printing ink further contains at least one resin selected from the group consisting of a cellulose-based resin, a vinyl chloride-based resin, a rosin-based resin, an acrylic resin, and a styrene-maleic acid copolymer resin, according to claims 1 to 1. 6 The base material recycling method according to any one.