JP6563344B2 - Ink composition, film sheet, and packaging material - Google Patents

Description

  The present invention relates to an ink composition used for a plastic substrate, a film sheet using the ink composition, and a packaging material including the film sheet.

  Application of ink to a plastic substrate by printing or painting is performed in various fields, and there are various forms of a plastic substrate such as a film, a sheet, and a molded body. For plastic substrates such as polyester, the ink adhesion is generally inferior. Therefore, after the surface treatment (easy adhesion treatment) is performed on the plastic substrate so that the ink is easily adhered, Application is in progress. The easy adhesion treatment includes surface modification treatment such as corona discharge treatment, plasma treatment, blast treatment, and ozone treatment, and surface coating such as primer treatment (see, for example, Patent Documents 1 and 2).

  For example, Patent Document 1 discloses an invention relating to a laminate ink composition for soft packaging mainly containing an organic solvent other than a predetermined binder resin, a colorant, and an aromatic organic solvent. In this example, a corona-treated nylon film is disclosed. And the use of corona-treated polyethylene terephthalate films. For example, Patent Document 2 discloses an invention relating to an ink composition for a light-resistant packaging material containing a predetermined pigment, a predetermined polyurethane resin, and a solvent. In this example, the use of a corona-treated polyethylene terephthalate film is disclosed. Have been described.

JP 2005-298618 A JP 2012-136582 A

  Corona discharge treatment, which is often used as an easy-adhesion treatment for a plastic substrate, is relatively deeply surface-treated (rather than plasma treatment) with respect to the surface of the treatment target (plastic substrate). For this reason, when corona discharge treatment is performed on a thin film having a thickness of, for example, 15 μm or less, and less than 8 μm, holes are likely to be formed. In addition, since it is costly to perform easy adhesion treatment on a plastic substrate, there is a demand for an ink that adheres well to a plastic substrate that has not been subjected to easy adhesion treatment. .

  In view of the above-described circumstances, the present inventors have conducted intensive research on inks that adhere well to a plastic substrate that has not been subjected to an easy adhesion treatment. As a result, when the polyester resin is used as the binder resin component in the ink, the inventors can obtain an ink layer that adheres well to the plastic substrate, but a large amount of the solvent used in the ink remains in the ink layer. It has been noticed that the large amount of residual solvent causes problems such as deterioration of blocking resistance of the ink layer and odor remaining. This detriment is particularly problematic when the plastic substrate is laminated with other films.

  Therefore, the present invention provides an ink composition that can form an ink layer with good adhesion to a plastic substrate that has not been subjected to an easy adhesion treatment and that has a small amount of residual solvent, and a film sheet using the ink composition. And it aims at providing a packaging material provided with this film sheet.

That is, according to the present invention, the following ink composition is provided.
[1] An ink composition to be applied to a plastic substrate, comprising a polyurethane resin, a polyester resin having a number average molecular weight of 1,000 to 10,000, and a polyisocyanate.
[2] The ink composition according to [1], wherein a solid content ratio of the polyurethane resin and the polyester resin is 99: 1 to 80:20 on a mass basis.
[3] The ink composition according to [1] or [2], further containing at least a pigment or a dye as a colorant.
[4] The ink composition according to [3], which contains light-shielding particles as the pigment.

Moreover, according to this invention, the film sheet shown below is provided.
[5] A film sheet comprising an ink layer formed from the ink composition according to any one of [1] to [4] on a film-like or sheet-like plastic substrate.
[6] The film sheet according to [5], wherein the plastic substrate is a polyethylene terephthalate film.

Furthermore, according to this invention, the packaging material shown below is provided.
[7] A packaging material comprising the film sheet according to [5] or [6].

  According to the present invention, it is possible to provide an ink composition capable of forming an ink layer with good adhesion to a substrate and having a small amount of residual solvent even when the plastic substrate is not subjected to easy adhesion treatment. it can. Moreover, according to this invention, the packaging material provided with the film sheet which used the ink composition, and the film sheet can be provided.

  Embodiments of the present invention will be described below, but the present invention is not limited to the following embodiments.

[Ink composition]
An ink composition according to an embodiment of the present invention is applied to a plastic substrate (ink composition for a plastic substrate), a polyurethane resin, and a polyester resin having a number average molecular weight of 1,000 to 10,000. And polyisocyanate. Therefore, this ink composition is a plastic substrate that has not been subjected to an easy adhesion treatment (plastic substrate that has not been subjected to an easy adhesion treatment). ) Can also form an ink layer exhibiting good adhesion. In this specification, “easy adhesion treatment” refers to known easy adhesion treatment such as corona discharge treatment, blast treatment, plasma treatment, ozone treatment (ultraviolet ray treatment), flame treatment, and primer treatment.

  The polyurethane resin, polyester resin, and polyisocyanate contained in the ink composition according to this embodiment can be used singly or in combination of two or more, and are also obtained from the market and used as they are. You can also. The ink composition can contain the following polyurethane resin, polyester resin, and polyisocyanate as components of the binder resin. The binder resin is a component that plays a role of adhering to a plastic substrate that is an adherend of the ink composition as an ink layer formed from the ink composition.

<Polyurethane resin>
The polyurethane resin contained in the ink composition is obtained, for example, by synthesizing a urethane prepolymer by a reaction between a diisocyanate compound and a polyol compound, and reacting with a chain extender and a reaction terminator as necessary. As the diisocyanate compound, the polyol compound, the chain extender, and the reaction terminator, known ones that have been conventionally used can be used.

  Examples of the diisocyanate compound include aromatic diisocyanate, aliphatic diisocyanate, and alicyclic diisocyanate.

  Specific examples of the aromatic diisocyanate include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylene-1,4-diisocyanate, xylene-1,3-diisocyanate, 4,4-diphenylmethane diisocyanate, 2, 4-diphenylmethane diisocyanate, 4,4-diphenyl ether diisocyanate, 2-nitrodiphenyl-4,4-diisocyanate, 2,2-diphenylpropane-4,4-diisocyanate, 3,3-dimethyldiphenylmethane-4,4-diisocyanate, 4 , 4-diphenylpropane diisocyanate, m-phenylene diisocyanate, p-phenylene diisocyanate, naphthylene-1,4-diisocyanate, naphthylene-1,5-diisocyanate, and 3,3- It can be exemplified methoxy diphenyl-4,4-diisocyanate. Specific examples of the aliphatic diisocyanate include tetramethylene diisocyanate, hexamethylene diisocyanate, and lysine diisocyanate. Specific examples of the alicyclic diisocyanate include isophorone diisocyanate, norbornane diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated xylene diisocyanate, and hydrogenated diphenylmethane diisocyanate. These diisocyanate compounds can be used singly or in combination of two or more.

  Examples of the polyol compound include polyester polyol, polycarbonate polyol, and polyether polyol. A polyol compound can be used individually by 1 type or in combination of 2 or more types.

  Examples of the polyester polyol include a polyester polyol or a polyesteramide polyol obtained by a dehydration polycondensation reaction between a polycarboxylic acid and a polyhydric alcohol or a secondary or tertiary amine. Specific examples of the polyvalent carboxylic acids include succinic acid, adipic acid, sebacic acid, azelaic acid, terephthalic acid, isophthalic acid, orthophthalic acid, hexahydroterephthalic acid, hexahydroisophthalic acid, hexahydroorthophthalic acid, and naphthalene dicarboxylic acid. Examples thereof include polycarboxylic acids such as acids and trimellitic acids, acid esters thereof, and acid anhydrides thereof, and one or more of these can be used. Specific examples of the polyhydric alcohols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1, 5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, neopentyl glycol, 1,8-octanediol, 1,9-nonanediol, diethylene glycol, dipropylene glycol, 1,4 -Low molecular alcohol compounds such as cyclohexanedimethanol, ethylene oxide or propylene oxide adduct of bisphenol A, trimethylolpropane, glycerin and pentaerythritol, and low molecular amino alcohol compounds such as monoethanolamine and diethanolamine , It can be used one or more of these. Specific examples of the secondary to tertiary amines include low-molecular amine compounds such as hexamethylenediamine, xylylenediamine, and isophoronediamine, and one or more of these can be used. Examples of polyester polyols include lactones obtained by ring-opening polymerization of cyclic ester (lactone) monomers such as ε-caprolactone and γ-valerolactone using, for example, a low molecular alcohol compound and a low molecular amino alcohol compound as an initiator. A polyester polyol can also be used.

  Examples of the polycarbonate polyol include those obtained by dehydrochlorination reaction of a low molecular alcohol compound and phosgene used for the synthesis of a polyester polyol, the low molecular alcohol compound, diethylene carbonate, dimethyl carbonate, diethyl carbonate, diphenyl carbonate, and the like. And those obtained by transesterification reaction.

  Examples of polyether polyols include, for example, low molecular alcohol compounds, low molecular amine compounds and low molecular amino alcohol compounds used in the synthesis of polyester polyols, and alkylenes such as ethylene oxide, propylene oxide, and butylene oxide with initiators such as phenols. Examples thereof include polyoxyethylene polyol, polyoxypropylene polyol, polytetramethylene ether polyol, and polyoxyethylene polyoxypropylene polyol obtained by ring-opening polymerization of oxide and tetrahydrofuran. Furthermore, the polyester ether polyol which uses the above-mentioned polyester polyol and polycarbonate polyol as an initiator is mentioned.

  Examples of chain extenders include aliphatic diamines such as ethylenediamine, propylenediamine, tetramethylenediamine, and hexamethylenediamine, alicyclic diamines such as isophorone diamine and 4,4′-dicyclohexylmethanediamine, and toluylenediamine. Aromatic diamines, aromatic aliphatic diamines such as xylenediamine, N- (2-hydroxyethyl) ethylenediamine, N- (2-hydroxyethyl) propylenediamine, and N, N′-di (2-hydroxyethyl) ethylenediamine Examples thereof include diamines having a hydroxyl group such as ethylene glycol, propylene glycol, 1,4-butanediol, neopentyl glycol, diethylene glycol, and triethylene glycol. Furthermore, polyamines such as diethylenetriamine and triethylenetetramine can be used in combination as long as the polyurethane resin does not gel.

  As reaction terminators, monoalkylamines such as n-propylamine and n-butylamine, dialkylamines such as di-n-butylamine, alkanolamines such as monoethanolamine and diethanolamine, and monoalcohols such as ethanol Etc. can be illustrated.

  In the production of the polyurethane resin, a known polyurethane resin production method can be used as it is, using the above materials. The polyurethane resin preferably has a weight average molecular weight (Mw) of 5,000 to 100,000, more preferably 10,000 to 60,000. When the Mw of the polyurethane resin is 5,000 or more, the film cohesion of the ink layer formed from the ink composition can be easily increased, and resistance such as abrasion resistance and hot water resistance can be easily obtained. From this viewpoint, the Mw of the polyurethane resin is more preferably 7,000 or more, and further preferably 10,000 or more. On the other hand, when the Mw of the polyurethane resin is 100,000 or less, the polyurethane resin is easily dissolved in a solvent, the fluidity of the ink (ink composition) becomes good, and it can be applied satisfactorily. From this viewpoint, the Mw of the polyurethane resin is more preferably 80,000 or less, and further preferably 60,000 or less. In addition, since the hardness of the polyurethane resin obtained will differ if the molecular weight, chemical structure, and equivalent ratio of the components constituting the polyurethane resin are different, the adhesion of the ink layer to the substrate and anti-blocking properties can be achieved by appropriately combining these components. It is possible to adjust sex. In this specification, Mw of a polyurethane resin is a value measured using gel permeation chromatography (GPC). This measurement was performed by connecting two TSKgel SuperHZM-H columns (6.0 nm ID × 150 mm) manufactured by Tosoh Corporation in series, using THF (tetrahydrofuran) as a mobile phase (solvent), a column temperature of 40 ° C., and a flow rate. It can be carried out at 0.3 mL / min, and a calibration curve can be created using genuine polystyrene as a standard sample, and the weight average molecular weight can be calculated.

  The content (blending amount) of the polyurethane resin is not particularly limited, but from the viewpoint of obtaining an ink layer with a small residual solvent amount, the solid content of the polyurethane resin in the total solid content excluding the solvent amount in the ink composition is 20 -80 mass% is preferable, More preferably, it is 30-70 mass%, More preferably, it is 40-60 mass%. Further, the content (blending amount) of the polyurethane resin in the total mass of the ink composition is not particularly limited as long as the ink composition can be satisfactorily applied according to the application method to be applied. For example, a gravure printing method is suitable as a gravure ink. From the viewpoint that can be utilized for the polyurethane resin, the solid content of the polyurethane resin is preferably 1 to 30% by mass, more preferably 5 to 25% by mass, and still more preferably 7 to 20% by mass.

<Polyester resin>
The polyester resin contained in the ink composition is a polymer having an ester bond in the main chain formed by copolymerization of a polyvalent carboxylic acid and / or an anhydride thereof and a polyol as a monomer.

Specific examples of the polyvalent carboxylic acid and its anhydride include malonic acid, phthalic acid, terephthalic acid, isophthalic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid, hexahydrophthalic acid, methylhexahydrophthalic acid, succinic acid, glutar acid, hexachloroendomethylene tetrahydrophthalic acid, endomethylene tetrahydrophthalic acid, endomethylene hexahydrophthalic acid, adipic acid, sebacic acid, azelaic acid, de Kajikarubon acid, cyclohexanedicarboxylic acid, trimellitic acid, pyromellitic acid, trimesic acid, And cyclopentanedicarboxylic acid, and anhydrides thereof. These polyvalent carboxylic acids and anhydrides thereof can be used alone or in combination of two or more.

  On the other hand, specific examples of polyols that can be used in the polyester resin include polyether polyols such as diethylene glycol, dipropylene glycol, triethylene glycol, and polyethylene glycol, polyester polyols, ethylene glycol, propylene glycol, 1,4-butanediol, , 3-pentanediol, neopentyl glycol, 1,6-hexanediol, cyclohexanediol, 2,2,4-trimethyl-1,3-pentanediol, glycerin, glycerin monoallyl ether, trimethylolethane, trimethylolpropane, And pentaerythritol. These polyols can be used individually by 1 type or in combination of 2 or more types.

  The combination of each component such as polyol and polyvalent carboxylic acid used for the synthesis of the polyester resin is not particularly limited, and the polyester resin may be a polymer according to one type of combination, or may be a combination of a plurality of types. Such a polymer may be used.

  The number average molecular weight (Mn) of the polyester resin is 1,000 to 10,000, preferably 1,000 to 9,000, and more preferably 1,000 to 8,000. When a polyester resin having an Mn of less than 1,000 is used, it is difficult to serve as a binder resin. When a polyester resin having Mn exceeding 10,000 is used, compatibility with the polyurethane resin is deteriorated, and gelation may occur when mixed. As a result, the adhesion between the plastic substrate and the ink layer may be reduced. On the other hand, a polyester resin having an Mn of 1,000 to 10,000 does not cause gelation when mixed with a polyurethane resin in the ink composition. The structure derived from the polyester resin having an Mn of 1,000 to 10,000 is present in the ink layer formed from the ink composition. Good adhesion to PET film and the like). In the present specification, Mn of the polyester resin is a value that can be measured by a vapor pressure infiltration method (VPO method) or GPC. As a commercial item of the polyester resin whose Mn is 1,000 to 10,000, for example, Eritel (registered trademark) series manufactured by Unitika, and Byron (registered trademark) series manufactured by Toyobo can be used. Among these commercially available products, the former Mn can be measured by the VPO method, and the latter Mn can be measured by GPC using THF (tetrahydrofuran) as a mobile phase (solvent).

  When the ink composition does not contain a polyester resin and contains a polyurethane resin, the adhesion to a non-easy-adhesion-treated plastic substrate (such as a non-easy-adhesion-treated PET film) is poor. On the other hand, the ink composition contains a polyurethane resin and a polyester resin having a number average molecular weight of 1,000 to 10,000 in combination, so that it is good even for a plastic substrate that has not been subjected to easy adhesion treatment. An ink layer showing adhesion can be obtained.

  In addition, when the ink composition does not contain a structure derived from a polyurethane resin, a very large amount of solvent remains in the ink layer formed from the ink composition, resulting in problems such as deterioration in blocking resistance of the ink layer and odor. There is. On the other hand, the ink composition contains a polyurethane resin and a polyester resin having a number average molecular weight of 1,000 to 10,000 in combination to suppress the amount of residual solvent in the ink layer formed from the ink composition. be able to. From the viewpoint of reducing the amount of residual solvent in the ink layer formed from the ink composition, the solid content ratio of the polyurethane resin and the polyester resin is preferably 99: 1 to 80:20, more preferably, on a mass basis. Is 98: 2-80: 20. The solid content of the polyurethane resin / the solid content of the polyester resin is preferably 99 to 4 on a mass basis, more preferably 80 to 4, and still more preferably 49 to 4.

  The content (blending amount) of the polyester resin is not particularly limited, but from the viewpoint of obtaining an ink layer that adheres well to the plastic substrate, the total solid content excluding the amount of solvent in the ink composition forming the ink layer As solid content of the polyester resin in it, 0.1-30 mass% is preferable, More preferably, it is 0.5-20 mass%, More preferably, it is 1-10 mass%. Further, the content (blending amount) of the polyester resin in the total mass of the ink composition is not particularly limited as long as the ink composition can be satisfactorily applied according to the application method to be applied. For example, a gravure printing method is suitable as a gravure ink. From the viewpoint that can be utilized for the polyester resin, the solid content of the polyester resin is preferably 0.05 to 15% by mass, more preferably 0.08 to 10% by mass, and still more preferably 0.1 to 5% by mass.

<Polyisocyanate>
As described above, the ink composition must contain polyisocyanate as a curing agent. By using polyisocyanate in combination with the aforementioned polyurethane resin and polyester resin as a component of the ink composition, the adhesion between the plastic substrate and the ink layer is improved. In addition, when the ink composition contains a polyisocyanate, a crosslinked structure is introduced into the ink layer formed from the ink composition, and accordingly, an effect of improving the heat resistance and solvent resistance of the ink layer can be expected.

  Examples of the polyisocyanate used as the curing agent include aromatic polyisocyanates, araliphatic polyisocyanates, alicyclic polyisocyanates, and aliphatic polyisocyanates.

  Examples of the aromatic polyisocyanate include m- or p-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,5-naphthalene diisocyanate (NDI), 4,4′-, 2,4′- or 2, Examples thereof include 2'-diphenylmethane diisocyanate (MDI), 2,4- or 2,6-tolylene diisocyanate (TDI), and 4,4'-diphenyl ether diisocyanate.

  Examples of the araliphatic polyisocyanate include 1,3- or 1,4-xylylene diisocyanate (XDI), 1,3- or 1,4-tetramethylxylylene diisocyanate (TMXDI), and the like. .

  Examples of the alicyclic polyisocyanate include 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate (isophorone diisocyanate; IPDI), 4,4 ′. -, 2,4'- or 2,2'-dicyclohexylmethane diisocyanate (hydrogenated MDI), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, and 1,3- or 1,4- Bis (isocyanatemethyl) cyclohexane (hydrogenated XDI) and the like can be mentioned.

  Examples of the aliphatic polyisocyanate include trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-, 2,3- or 1,3- Examples include butylene diisocyanate and 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate.

  As the polyisocyanate contained in the ink composition, a trifunctional or higher functional polyisocyanate having three or more isocyanate groups in one molecule can be used, and a trifunctional polyisocyanate is preferable. If a trifunctional polyisocyanate is used, a sufficient cross-linked structure can be obtained as compared with a bifunctional one, and an effect of improving solvent resistance can be expected. Examples of the trifunctional polyisocyanate include derivatives of the aforementioned polyisocyanates (diisocyanates), triphenylmethane triisocyanate, and 1-methylbenzole-2,4,6-triisocyanate. Among these, more preferable examples of the aforementioned polyisocyanate derivatives include adduct-modified products, burette-modified products, and nurate-modified products. In addition, polyisocyanate can be used individually by 1 type or in combination of 2 or more types.

  The content (blending amount) of the polyisocyanate is not particularly limited, but from the viewpoint of obtaining the effect of blending the polyisocyanate, the solid content of the polyisocyanate in the total solid content excluding the solvent amount in the ink composition forming the ink layer. As a fraction, 1-50 mass% is preferable, More preferably, it is 5-40 mass%. Further, the content (blending amount) of the polyisocyanate in the total mass of the ink composition is not particularly limited as long as the ink composition can be satisfactorily applied according to the application method to be applied. For example, a gravure printing method is suitable as a gravure ink. From a viewpoint which can be utilized for, as solid content of polyisocyanate, 0.1-20 mass% is preferable, for example, More preferably, it is 0.5-15 mass%, More preferably, it is 1-10 mass%.

<Colorant>
The ink composition may contain a colorant. The ink composition preferably contains at least a pigment or a dye as a colorant. By containing the colorant in the ink composition, the ink layer formed from the ink composition can be colored. As the colorant, known pigments and dyes can be used, and either one or both of pigments and dyes can be used. Examples of the pigment include colored inorganic pigments such as bitumen, ultramarine blue, bengara, iron black, and yellow iron oxide, monoazo pigments, disazo pigments, condensed azo pigments, phthalocyanine pigments, anthraquinone pigments, quinacridone pigments, Colored organic pigments such as isoindolinone pigments, thioindigo pigments, and pyrrolopyrrole pigments, white pigments such as titanium oxide, zinc oxide, lead oxide, and zinc sulfide, silver pigments such as aluminum paste, and carbon black and azomethineazo And black pigments such as perylene pigments can be used.

The ink composition may contain light-shielding particles as the pigment. Here, “light-shielding particles” refers to particulate matter that imparts light-shielding properties to an ink layer formed from an ink composition. The ink composition containing light-shielding particles can be used for forming a light-shielding ink layer.
A light-shielding film sheet can be obtained by providing the light-shielding ink layer on a film-like or sheet-like plastic substrate.

  The light-shielding particles are not particularly limited as long as they can impart light-shielding properties to the ink layer formed from the ink composition. For example, a known pigment similar to the colorant described above can be used. Further, as the light-shielding particles, metal particles, metal oxide particles, composite particles in which two or more of them are combined, and the like can also be used. Examples of the metal particles include any one of gold, silver, copper, palladium, nickel, and aluminum, and alloy particles obtained by alloying two or more of these metal particles. Examples of the metal oxide particles include metal oxide particles of copper, tin, tungsten, and titanium.

  As the light-shielding particles, carbon black, aluminum, silver and the like are preferable, and black pigments such as the above-described carbon black can be suitably used. Among the black pigments, it is more preferable to use carbon black as the light-shielding particles from the viewpoint of being able to form a black light-shielding ink layer having excellent concealability and further from the viewpoint of dispersibility and cost. The content of carbon black in the ink composition forming the light-shielding ink layer can be appropriately adjusted so that sufficient light-shielding properties can be obtained for the ink layer. From the viewpoint of obtaining sufficient light-shielding properties for the ink layer, the content of carbon black in the ink composition is, for example, preferably 2% by mass or more, more preferably 5% by mass or more. Further, the upper limit of the carbon black content in the ink composition is not particularly limited, but if it is too much, the cost becomes uselessly high, and from the viewpoint of maintaining the fluidity of the ink composition, it is 30% by mass or less. Preferably, it is 20% by mass or less.

<Solvent>
The ink composition may contain a solvent. Although it does not specifically limit as a solvent, For example, a ketone solvent, a hydrocarbon solvent, an ester solvent, etc. are preferable. Specific examples of the ketone solvent include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methylcyclohexanone, and diacetone alcohol. Specific examples of the hydrocarbon solvent include toluene, cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, cyclopentane, methylcyclopentane, and ethylcyclopentane. Specific examples of the ester solvent include ethyl acetate, propyl acetate, and butyl acetate.

  As the solvent, a solvent compatible with the aforementioned solvent may be used. As such a solvent, for example, an alcohol solvent and a glycol ether solvent can be used. Examples of the alcohol solvent include methanol, ethanol, 1-propanol, 2-propanol, isopropyl alcohol, and various butanols. Examples of glycol ether solvents include ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, and Examples thereof include propylene glycol monoethyl ether acetate. Each of the solvents that can be contained in the ink composition can be used alone or in combination of two or more. Moreover, it is also possible to design a water-based ink by appropriately combining water and an alcohol solvent as a solvent in accordance with printability.

<Other additives>
The ink composition contains additives such as a plasticizer, a matting agent, an antisettling agent, a leveling agent, an antifoaming agent, a pigment dispersant, and a silane coupling agent as long as the object of the present invention is not hindered. It may be.

[Method for producing ink composition]
The method for producing the ink composition is not particularly limited. For example, a mixture containing the above-described polyurethane resin, polyester resin, and polyisocyanate, which are essential components as an ink composition, and, if necessary, a mixture containing other resin components, the above-described colorant, solvent, and the like. By preparing the ink composition, an ink composition can be produced.

  It is preferable that the manufacturing method of the ink composition of this embodiment includes the process (preparation process) of preparing the mixture containing the above-mentioned polyurethane resin and polyester resin. The mixture prepared in this preparation step contains a polyurethane resin and a polyester resin, which are essential components as an ink composition, but preferably does not contain the aforementioned polyisocyanate. Moreover, it is preferable that the mixture prepared in a preparation process contains the above-mentioned coloring agent and solvent, and may contain other resin components other than the above-mentioned polyurethane resin and polyester resin as needed.

  When the ink composition contains a colorant (pigment), the process for finely dispersing the colorant (pigment) particles to a desired particle size in the preparation step or after the preparation step (when the ink composition contains a colorant (pigment)) (Dispersing step) is preferably included. In this dispersion step, for example, various dispersers such as a paint shaker, a ball mill, an attritor, a sand mill, a bead mill, a dyno mill, a roll mill, an ultrasonic mill, and a high-pressure collision disperser can be used. In the dispersion step, the dispersion process may be performed once or a plurality of times using one kind of disperser, or the dispersion process may be performed a plurality of times using two or more kinds of dispersers together.

  It is preferable that the manufacturing method of an ink composition includes the process (dilution process) of diluting the mixture after a preparation process, or the dispersion liquid after a dispersion process to a desired viscosity with a dilution solvent. By this dilution step, the ink composition can be diluted with a solvent until the viscosity of the ink composition becomes a viscosity corresponding to the coating method, and the target ink composition can be obtained.

  Furthermore, in this production method, it is preferable to add the aforementioned polyisocyanate to the mixture after the preparation step or the dispersion after the dispersion step, and it is more preferable to perform this addition in the dilution step or after the dilution step. As a result, when the ink composition is applied (immediately before application), the polyisocyanate is mixed, and before the viscosity increases due to the reaction between the polyisocyanate and the polyurethane resin or polyester resin, It is possible to apply an ink composition to the material. From such a manufacturing viewpoint, the above-described ink composition is also preferably in the form of a kit (ink composition kit). In this case, the polyurethane resin and the polyester resin are separated from the polyisocyanate to obtain an ink composition kit comprising a resin-containing composition containing the polyurethane resin and the polyester resin and a curing agent-containing composition containing the polyisocyanate. be able to. In this case, it is preferable that the above-described other resin components, colorants, solvents, and the like used as necessary are contained in the resin-containing composition.

  The ink composition of the present embodiment described in detail above contains a polyurethane resin, a polyester resin having a number average molecular weight of 1,000 to 10,000, and a polyisocyanate. In addition, it is possible to form an ink layer that adheres well and has a small amount of residual solvent. Therefore, if this ink composition is used and an ink layer formed from the ink composition is provided on a film-like or sheet-like plastic substrate, the film sheet has anti-blocking properties and no odor problems. Can be obtained. From these advantages, the ink composition of the present embodiment can be suitably used as a gravure ink for back printing, more preferably as a gravure ink for back printing lamination, and more preferably a gravure for packaging back printing lamination. It can be used as an ink.

  Moreover, since the ink composition of this embodiment adhere | attaches favorably with respect to a plastic base material as above-mentioned, the plastic base material of a non-easily-adhesion process can also be used as a plastic base material. By using a non-easily-adhesive plastic substrate, there is no cost for the easy-adhesion treatment for that substrate, so it is possible to reduce the manufacturing cost of products using plastic substrates to which the ink composition is applied. is there.

[Plastic substrate]
The ink composition according to this embodiment can be applied to various plastic substrates. It does not specifically limit as a form of the plastic base material, For example, a film form, a sheet form, and a molded object can be mentioned. Of these forms, a film shape or a sheet shape is preferable, and a film shape is more preferable.

  The material of the plastic substrate to which the ink composition can be applied is not particularly limited. For example, polyesters such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyolefins such as polyethylene (PE) and polypropylene (PP), and Examples include polystyrene (PS), polycarbonate (PC), polymethyl methacrylate (PMMA), polyamide (PA), polyimide (PI), and celluloses.

  The plastic substrate may or may not be subjected to easy adhesion treatment. Among the plastic substrates, a PET film is more preferable because the ink composition is more easily adhered even if the easy adhesion treatment is not performed. Since the ink composition exhibits good adhesion to both the easy adhesion treated PET film and the non-adhesion treated PET film, the presence or absence of the easy adhesion treatment may be appropriately selected. The use of a non-easy-adhesion-treated PET film is more preferable because the cost required for the easy-adhesion treatment can be reduced.

  Although it does not specifically limit as thickness of a film-form plastic base material (plastic film), For example, 1-50 micrometers is preferable, More preferably, it is 2-30 micrometers, More preferably, it is 2-25 micrometers. In addition, since the ink layer formed from the above-described ink composition adheres well to a plastic substrate that is not easily adhesively treated, it is difficult to perform an easily adhesive treatment such as a corona treatment. A plastic film having a thickness of 15 μm or less or a thickness of 10 μm or less is also suitable, and a plastic film having a thickness of less than 8 μm is also suitable.

[Film sheet]
The film sheet which concerns on one Embodiment of this invention equips the above-mentioned film-form or sheet-form plastic base material with the ink layer formed from the above-mentioned ink composition. These film sheets are suitable for use as a packaging material to be described later. In this specification, the term “film sheet” means that both a film and a sheet are included.

  Although the plastic base material in a film sheet is not specifically limited, It is more preferable to use the polyethylene terephthalate (PET) film which can be used also in a non-adhesion process.

  In the film sheet, the ink layer may be provided on substantially the entire surface of one side of the plastic substrate, or may be provided on a part thereof. Moreover, the ink layer may be provided on one side (one side) of the plastic substrate, or may be provided on both sides. From the viewpoint that the film sheet can be suitably used as a packaging material, the ink layer is preferably provided on one surface (back surface) of the plastic substrate.

  The method for applying the ink composition to the film-like or sheet-like plastic substrate is not particularly limited, and various application methods such as various known printing methods and coating methods can be used depending on the purpose. Examples of printing techniques include gravure printing, flexographic printing, offset printing, letterpress printing, and screen printing. Examples of the coating method include a gravure coater, a comma coater, a roll coater, air gun coating, and immersion coating.

  Among the above-described coating methods, a printing method is preferable, and a gravure printing method is more preferable from the viewpoint that mass production is possible at a low cost for a PET film suitable as a plastic substrate. Therefore, as a film sheet, a printing film sheet (printing film or printing sheet) provided with the ink layer formed by printing the above-mentioned ink composition on the above-mentioned film-like or sheet-like plastic substrate is preferable.

  The film sheet of this embodiment may be provided with an adhesive layer on the surface of the ink layer and / or on the surface of the plastic substrate opposite to the surface on which the ink layer is provided. When a film sheet is provided with an adhesive layer, it can be used by sticking the film sheet to an object to be adhered. In addition, the film sheet is laminated by laminating a sealant film such as polyolefin or polyester described in the explanation of the plastic substrate, or an aluminum foil or an aluminum vapor deposition film by a dry laminating method through a general laminating adhesive. It can also be a film sheet.

  The film sheet of the present embodiment described above has an ink layer that adheres well to a plastic substrate and has a small amount of residual solvent due to the ink composition described above, and thus has a negative effect such as deterioration in blocking resistance and odor remaining. There is no. Therefore, this film sheet can be used for various applications such as packaging materials, decorative materials, optical materials, electrical / electronic materials, and battery materials. The film sheet can be more suitably used as a packaging material for packaging adhesive tapes in various applications, foods, pharmaceuticals, medical materials, and the like. In addition, by using a non-easy-adhesion-treated PET film for the plastic substrate in the film sheet of the present embodiment, there is no cost for easy-adhesion treatment for the substrate, and therefore an ink layer that is well adhered to the PET film is provided. It is also possible to obtain a film sheet at low cost.

[Packaging materials]
The packaging material which concerns on one Embodiment of this invention is equipped with the above-mentioned film sheet. This packaging material can be formed from the aforementioned film sheet. The form of the packaging material is not particularly limited, and various forms such as a bag shape, a box shape, a pouch shape, and a pack shape can be employed. In order to produce a packaging material using a film sheet, various sealing methods such as adhesion with an adhesive and heat sealing can be used. The use of the packaging material is not particularly limited, and can be used as a packaging material for foods, pharmaceuticals, medical materials, chemicals, electrical / electronic parts, and the like.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited to these Examples. In the examples and comparative examples, “parts” and “%” are based on mass unless otherwise specified.

<Preparation of polyester resins A to D>
(Preparation of polyester resin A)
Add 30 parts of methyl ethyl ketone and 35 parts of toluene to 30 parts of the trade name “Eritel (registered trademark) UE-3320” (Mn1,800), which is a thermoplastic saturated copolymer polyester resin manufactured by Unitika Ltd. The mixture was stirred at 40 ° C. for 2 hours to obtain a polyester resin solution A having a solid content of 30%.

(Preparation of polyester resin B)
Add 30 parts of methyl ethyl ketone and 35 parts of toluene to 30 parts of the product name “Eritel (registered trademark) UE-3380” (Mn8,000) which is a thermoplastic saturated copolymer polyester resin manufactured by Unitika Ltd. The mixture was stirred at 40 ° C. for 2 hours to obtain a polyester resin solution B having a solid content of 30%.

(Preparation of polyester resin C)
Add 30 parts of methyl ethyl ketone and 35 parts of toluene to 30 parts of "Elitel (registered trademark) UE-9800" (Mn 13,000), which is a thermoplastic saturated copolymer polyester resin manufactured by Unitika Ltd. The mixture was stirred at 40 ° C. for 2 hours to obtain a polyester resin solution C having a solid content of 30%.

(Preparation of polyester resin D)
To 30 parts of the trade name “Eritel (registered trademark) UE-3210” (Mn: 20,000), which is a thermoplastic saturated copolymer polyester resin manufactured by Unitika, 35 parts of methyl ethyl ketone and 35 parts of toluene are added. And a polyester resin solution D having a solid content of 30% was obtained.

<Manufacture of ink composition>
(Example 1: Production of black ink A)
Polyurethane resin solution having a solid content of 30% (manufactured by Hitachi Chemical Co., Ltd., trade name “TA21-124X”, Mw: 50,100, solvent: methyl ethyl ketone (24.5%) / ethyl acetate (35%) / isopropyl alcohol (10. 5%)), 1 part of polyester resin solution A, 20 parts of methyl ethyl ketone, 10 parts of ethyl acetate, 10 parts of toluene, 10 parts of isopropyl alcohol, and carbon black (trade name “Mitsubishi Chemical Corporation” 10 parts of “MA-11”, Examples 2 to 5 and Comparative Examples 1 to 4 described below) were mixed and dispersed with dynomill to obtain black ink a. To this black ink a, 5 parts of a trifunctional polyisocyanate-based curing agent (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name “RAMIC B HARDNER”, HDI derivative, solid content: 30%) is added. 30 parts of a mixed solvent of methyl ethyl ketone / toluene / isopropyl alcohol (volume ratio: 5/3/2, manufactured by Dainichi Seika Kogyo Co., Ltd., trade name “Ramic F No. 2 Solvent (S)”) was added, and ink ink A Got.

(Example 2: Production of black ink B)
33 parts of a 30% solid polyurethane resin solution used in Example 1, 7 parts of polyester resin solution A, 20 parts of methyl ethyl ketone, 10 parts of ethyl acetate, 10 parts of toluene, 10 parts of isopropyl alcohol, and carbon 10 parts of black was blended and dispersed with a dyno mill to obtain black ink b. To this black ink b, 5 parts of the polyisocyanate curing agent used in Example 1 was added, and then 30 parts of the diluent solvent used in Example 1 was added to obtain black ink B.

(Example 3: Production of black ink C)
40 parts of a 30% solid polyurethane resin solution used in Example 1, 1 part of polyester resin solution B, 20 parts of methyl ethyl ketone, 10 parts of ethyl acetate, 10 parts of toluene, 10 parts of isopropyl alcohol, and carbon 10 parts of black was blended and dispersed with a dyno mill to obtain black ink c. To this black ink c, 5 parts of the polyisocyanate curing agent used in Example 1 was added, and then 30 parts of the diluent solvent used in Example 1 was added to obtain black ink C.

(Example 4: Production of black ink D)
33 parts of a 30% solid polyurethane resin solution used in Example 1, 7 parts of polyester resin solution B, 20 parts of methyl ethyl ketone, 10 parts of ethyl acetate, 10 parts of toluene, 10 parts of isopropyl alcohol, and carbon 10 parts of black was mixed and dispersed with a dyno mill to obtain black ink d. To this black ink d, 5 parts of the polyisocyanate curing agent used in Example 1 was added, and then 30 parts of the diluent solvent used in Example 1 was added to obtain black ink D.

(Example 5: Production of black ink E)
25 parts of a 30% solid polyurethane resin solution used in Example 1, 15 parts of polyester resin solution B, 20 parts of methyl ethyl ketone, 10 parts of ethyl acetate, 10 parts of toluene, 10 parts of isopropyl alcohol, and carbon 10 parts of black was blended and dispersed with a dyno mill to obtain black ink e. To this black ink e, 5 parts of the polyisocyanate curing agent used in Example 1 was added, and then 30 parts of the diluent solvent used in Example 1 was added to obtain black ink E.

(Comparative Example 1: Production of black ink F)
40 parts of a polyurethane resin solution having a solid content of 30% used in Example 1, 20 parts of methyl ethyl ketone, 10 parts of ethyl acetate, 10 parts of toluene, 10 parts of isopropyl alcohol, and 10 parts of carbon black were mixed, To obtain black ink f. To this black ink f, 5 parts of the polyisocyanate curing agent used in Example 1 was added, and then 30 parts of the diluent solvent used in Example 1 was added to obtain black ink F.

(Comparative Example 2: Production of black ink G)
40 parts of a 30% solid polyurethane resin solution used in Example 1, 10 parts of polyester resin solution C, 20 parts of methyl ethyl ketone, 10 parts of ethyl acetate, 10 parts of toluene, 10 parts of isopropyl alcohol, and carbon 10 parts of black was mixed and dispersed with a dyno mill to obtain black ink g. To this black ink g, 5 parts of the polyisocyanate curing agent used in Example 1 was added, and then 30 parts of the diluent solvent used in Example 1 was added to obtain black ink G.

(Comparative Example 3: Production of black ink H)
40 parts of a 30% solid polyurethane resin solution used in Example 1, 1 part of polyester resin solution B, 20 parts of methyl ethyl ketone, 10 parts of ethyl acetate, 10 parts of toluene, 10 parts of isopropyl alcohol, and carbon 10 parts of black was mixed and dispersed with a dyno mill to obtain black ink h. To this black ink h, 30 parts of the diluent solvent used in Example 1 was added without adding a polyisocyanate-based curing agent to obtain black ink H.

(Comparative Example 4: Production of black ink I)
40 parts of polyester resin solution D, 20 parts of methyl ethyl ketone, 10 parts of ethyl acetate, 20 parts of toluene, and 10 parts of carbon black were mixed and dispersed with dynomill to obtain black ink i. 5 parts of the polyisocyanate curing agent used in Example 1 was added to this black ink i, and then a mixed solvent of methyl ethyl ketone / toluene (volume ratio: 1/1, manufactured by Dainichi Seika Kogyo Co., Ltd. 40 parts of the name “Almic No. 18 No. 2 solvent”) was added to obtain black ink I.

  The formulations of black inks A to E produced in Examples 1 to 5 are shown in Table 1, and the formulations of black inks F to I produced in Comparative Examples 1 to 4 are shown in Table 2.

<Manufacture of film sheet>
(Example 6: Production of printing film 1)
A polyethylene terephthalate (PET) film (Futamura Chemical Co., Ltd., “FE2000”, 12 μm thick, no corona treatment on both sides) was used as a film-like plastic substrate. On one surface (base material surface) of this PET film, the black ink A produced in Example 1 was printed once by the gravure printing method so that the coating amount was 1 g / m ² -dry, and then Aging was performed at 40 ° C. for 3 days. Thus, the printing film 1 provided with the ink layer formed from the black ink A on one side of the PET film was produced.

(Example 7: Production of printing film 2)
In Example 7, black ink A used in Example 6 was formed from black ink B on one side of a PET film in the same manner as in Example 6 except that it was changed to black ink B manufactured in Example 2. A printed film 2 having an ink layer was produced.

(Example 8: Production of printing film 3)
In Example 8, black ink A used in Example 6 was changed from black ink C manufactured in Example 3 to black ink C formed on one side of a PET film in the same manner as in Example 6. The printing film 3 provided with the made ink layer was manufactured.

(Example 9: Production of printing film 4)
In Example 9, black ink A used in Example 6 was changed from black ink D manufactured in Example 4 to black ink D on one side of a PET film in the same manner as in Example 6. The printing film 4 provided with the made ink layer was manufactured.

(Example 10: Production of printing film 5)
In Example 10, except that the black ink A used in Example 6 was changed to the black ink E manufactured in Example 5, the black ink E was formed on one side of the PET film in the same manner as in Example 6. The printing film 5 provided with the made ink layer was manufactured.

(Comparative Examples 5 to 8: Production of printing films 6 to 9)
In Comparative Examples 5 to 8, printing was performed in the same manner as in Example 6, except that the black ink A used in Example 6 was changed to the black inks F to I manufactured in Comparative Examples 1 to 4, respectively. Films 6-9 were produced.

  Table 3 shows the black ink used in the ink layers of the printing films 1 to 9 produced in Examples 6 to 10 and Comparative Examples 5 to 8.

  The following physical property evaluation was performed about the printing films 1-9 manufactured in Examples 6-10 and Comparative Examples 5-8. The results are shown in Tables 4 and 5 below.

<Adhesion test>
Press the Nichiban cellophane tape 18mm width on the printed film 1-9, then peel off strongly, and visually check whether the ink layer is peeled off, the ink layer on the plastic substrate (non-adhesive PET film) An adhesion test was performed. The print film in which the ink layer was not peeled off was indicated as “◯” in the table, and the adhesion was evaluated as good, and the print film from which the ink layer was peeled off was indicated as “x” in the table, and was evaluated as having poor adhesion. .

<Measurement of residual solvent>
Using a personal gas chromatograph GC-8A (column; PEG600, detector; FID, column temperature; 70 ° C.) manufactured by Shimadzu Corporation, the amount of residual solvent in the printed films 1 to 9 was measured. The measurement method was based on the residual solvent measurement method described in the “Management Equipment Manual for the Production of Soft Packaging Materials” edited by the Flexible Packaging Sanitation Council. The printed film whose residual solvent amount was less than 5 mg / m ^{2 in} total was indicated as “A” in the table and evaluated that the residual solvent amount was very small. A printed film having a residual solvent amount of 5 mg / m ² or more and less than 15 mg / m ² was indicated as “B” in the table and evaluated as having a small residual solvent amount. A printed film having a residual solvent amount of 15 mg / m ² or more was indicated as “C” in the table and evaluated as having a large residual solvent amount.

  As shown in Table 4, the printed films 1 to 5 obtained in Examples 6 to 10 were excellent in adhesion to the non-corona-treated polyethylene terephthalate film, and it was confirmed that the amount of residual solvent was small. In the printing films 1 to 4 obtained in Examples 6 to 9, since the solid content ratio of the polyurethane resin and the polyester resin used in the ink layer was in the range of 99: 1 to 80:20, the residual solvent amount was further increased. It was confirmed that it was less.

  On the other hand, since the printing film 6 obtained in Comparative Example 5 did not use a polyester resin for the ink layer, the adhesion of the ink layer to the substrate was poor. In the printed film 7 obtained in Comparative Example 6, since the number average molecular weight of the polyester resin C used in the ink layer was high, the polyester resin C was incompatible with the polyurethane resin and caused gelation. The result was poor. In the printing film 8 obtained in Comparative Example 7, since the polyisocyanate was not used for the ink layer, the adhesion of the printing layer to the substrate was poor. Moreover, in the printing film 9 obtained in the comparative example 8, since the ink I which did not mix | blend a polyurethane resin was used for the ink layer, the result that the amount of residual solvents was very much was brought.

<Manufacture of laminate film>
(Example 11)
Next, a drying agent was applied in an amount of 3 g / m ² to the surface on the ink layer side of the printing film 1 produced in Example 6 and dried. Then, the printing film 1 and the sealant film were bonded together using a dry laminating machine (nip roll temperature 80 ° C.) and aged at 40 ° C. for 72 hours to obtain a laminated film 1. As the drying agent, 2 parts by mass of Seika Bond C-76 (curing agent for drying agent manufactured by Dainichi Seika Kogyo Co., Ltd.) is mixed with 17 parts by mass of Seika Bond E372 (Daiichi Seika Kogyo Co., Ltd. drying agent), Thereafter, a solution prepared by diluting the total solid content to 30% with ethyl acetate was used. As the sealant film, Trefan ZK-93KM (unstretched polypropylene film manufactured by Toray Film Processing Co., Ltd., film thickness 70 μm) was used.

(Examples 12 to 15)
In Examples 12 to 15, lamination was performed in the same manner as in Example 11 except that the printing film 1 used in Example 11 was changed to printing films 2 to 5 manufactured in Examples 7 to 10, respectively. Films 2 to 5 were obtained.

<Measurement of laminate strength>
Each of the above laminate films was cut to a width of 15 mm, and the laminate strength was measured by a T-type peel test. A Tensilon universal testing machine RTG-1225 (manufactured by AND) was used for the measurement. When the laminate strength was 1 N / 15 mm or more, it was evaluated as “◯” and the laminate strength was evaluated as sufficient. When the laminate strength was less than 1 N / 15 mm, it was evaluated as “x”, and the laminate strength was evaluated as insufficient.

  As shown in Table 6, even when a non-corona-treated PET film was used, the laminate strength was at a practical level of 1 N / 15 mm or more. Therefore, since the cost for easy adhesion treatment such as corona treatment can be suppressed, an inexpensive laminate film can be produced. From these results, the laminate films 1 to 5 obtained in Examples 11 to 15 can be suitably used not only as packaging materials but also as film sheets for various uses.

  The ink composition according to an embodiment of the present invention can be suitably used for, for example, a film sheet constituting a packaging material that contains food, pharmaceuticals, medical materials, chemicals, electrical / electronic components, and the like.

Claims (7)

An ink composition to be applied to a plastic substrate not subjected to easy adhesion treatment ,
Containing a polyurethane resin, a thermoplastic saturated copolymer polyester resin having a number average molecular weight of 1,000 to 10,000, a solvent, and a polyisocyanate ;
The ink composition whose content as solid content of the said polyurethane resin is 30-70 mass% in the total solid of the said ink composition .   The ink composition according to claim 1, wherein a solid content ratio of the polyurethane resin and the polyester resin is 99: 1 to 80:20 on a mass basis.   The ink composition according to claim 1 or 2, further comprising at least a pigment or a dye as a colorant.   The ink composition according to claim 3, wherein the pigment contains light-shielding particles. A film sheet provided with the ink layer formed from the ink composition of any one of Claims 1-4 in the film-form or sheet-form plastic base material in which the easily bonding process is not performed .   The film sheet according to claim 5, wherein the plastic substrate is a polyethylene terephthalate film.   A packaging material comprising the film sheet according to claim 5 or 6.