JP6988423B2 - Inkjet recording medium, image forming method and film laminate manufacturing method - Google Patents

Description

The present invention relates to an inkjet recording medium, an image forming method, and a method for producing a film laminate.

The inkjet method is used in various printing fields because it can form an image easily and inexpensively. As the ink (inkjet ink) used in the inkjet method, water-based inks using water and water-based solvents are often used from the viewpoint of reducing the environmental load.

On the other hand, since the water-based ink is difficult to be absorbed by a non-water-absorbing recording medium such as a film, there are problems that ink bleeding occurs and it is difficult to obtain adhesion to the recording medium.

On the other hand, for example, Patent Document 1 describes a step of applying a treatment liquid containing polyvinyl alcohol (water-soluble resin) and water to a recording medium, and an aqueous system containing a pigment in a recording medium to which the treatment liquid is applied. An inkjet recording method including a step of applying ink by an inkjet method to form an image is disclosed.

Japanese Unexamined Patent Publication No. 2015-85576

In the method of Patent Document 1, since the ink absorbency of the recording medium to which the treatment liquid is applied is enhanced, it is considered that the ink bleeding can be suppressed to some extent. However, the adhesion of the obtained image was not sufficient. Further, when a film is further laminated (laminated) on the obtained image-forming product to form a film laminate, resin or the like is easily eluted from the image, and sufficient adhesive strength (lamination) between the film and the image-forming product is obtained. Strength) was not obtained either.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an inkjet recording medium which suppresses ink bleeding and has good adhesion to an image, and an image forming method using the same. And. It is also an object of the present invention to provide a method for producing a film laminate having high lamination strength.

[1] It has a film base material, a treatment layer arranged on the film base material, and a treatment layer containing a curing agent and a water-soluble resin having a functional group that reacts with the curing agent, and the film thickness of the treatment layer. Is 0.3 μm or more and 3.0 μm or less, and the amount of the water-soluble resin extracted from the treated layer when immersed in water at 40 ° C. for 1 hour is 0.1 g / m ² or more and 2.0 g / g /. A recording medium for inkjet, which is ^{m 2 or less.}
[2] The recording medium for inkjet according to [1], wherein the functional group that reacts with the curing agent is selected from the group consisting of a hydroxyl group, an amino group and a carboxyl group.
[3] The recording medium for inkjet according to [1] or [2], wherein the curing agent is selected from the group consisting of an isocyanate-based curing agent, a carbodiimide-based curing agent, an oxazoline-based curing agent, and an epoxy-based curing agent.
[4] The inkjet recording medium according to any one of [1] to [3], wherein the treated layer further contains a compound that agglomerates a coloring material.
[5] The inkjet recording medium according to any one of [1] to [4], wherein the treated layer further contains a water-dispersible resin.
[6] The recording medium preparation step of preparing the inkjet recording medium according to any one of [1] to [5], and ink jet containing at least a coloring material and water on the inkjet recording medium. An image forming method comprising an ink applying step of applying by a method and an ink drying step of drying the applied ink at a temperature of 40 ° C. or higher to form an image forming layer.
[7] In the ink drying step, when the obtained image-forming product is immersed in water at 40 ° C. for 1 hour, the total amount of the treated layer and the water-soluble resin extracted from the image-forming layer is 0.1 g / g. The image forming method according to [6], which is performed so as to be less than m ^2.
[8] The ink drying step includes a step of drying the ink at a second drying temperature and a step of further heating the ink at a second heating temperature lower than the second drying temperature, according to [7]. The image forming method described.
[9] The recording medium preparation step includes a treatment liquid coating step of applying a treatment liquid containing at least a curing agent, a water-soluble resin having a functional group that reacts with the curing agent, and water to a film substrate. The image forming method according to any one of [6] to [8], which comprises a treatment liquid drying step of drying the treatment liquid applied to the film substrate at a temperature of 40 ° C. or higher to form a treatment layer. ..
[10] The treatment liquid drying step includes a step of drying the treatment liquid at a first drying temperature and a step of further heating the treatment liquid at a first heating temperature lower than the first drying temperature. 9] The image forming method according to.
[11] The image forming method according to any one of [6] to [10], wherein the ink does not contain a water-dispersible resin.
[12] The image forming method according to any one of [6] to [11], wherein the coloring material is titanium oxide.
[13] By the image forming method according to any one of [6] to [12], an image forming step of forming an image forming layer on an inkjet recording medium and an adhesive layer on the image forming layer are provided. A method for producing a film laminate, which comprises a film laminating step of laminating films.

According to the present invention, an inkjet recording medium that suppresses ink bleeding, has good adhesion to an image, and has good adhesive strength even when a film is laminated, and image formation using the same. A method as well as a method for producing a film laminate can be provided.

In the present invention, in a recording medium having a film base material and a treated layer, a cured state of a water-soluble resin having a functional group that reacts with a curing agent contained in the treated layer and having a thickness of the treated layer within a predetermined range. Is adjusted so that the amount of the water-soluble resin extracted from the treatment layer when immersed in water at 40 ° C. for 1 hour is 0.1 g / m ² or more and 2.0 g / m ^{2 or less.} As a result, the water-soluble resin having a functional group that reacts with the curing agent contained in the treated layer can be in a state of not being completely cured (incompletely cured state). It is presumed that the ink applied by the inkjet method easily penetrates into such a treated layer, and bleeding between the applied inks is prevented.

Further, in the image forming method using such a recording medium, after applying the ink to the processing layer, the ink is dried at a temperature of 40 ° C. or higher. Above all, in the drying of the ink, the total amount of the water-soluble resin having a functional group that reacts with the curing agent, which is extracted from the treatment layer and the image-forming layer when the obtained image-forming product is immersed in water at 40 ° C. for 1 hour, is used. It is preferable to carry out under the condition that the amount is less than 0.1 g / m ^2. As a result, when the ink is applied to the treated layer, the elution of the water-soluble resin contained in the treated layer into the ink is easily promoted, and the ink is easily diffused to the vicinity of the coloring material. Further, since the water-soluble resin eluted in the ink can be sufficiently reacted with the curing agent after the ink is applied to the treated layer, it is presumed that the adhesion of the image and the laminating strength are enhanced. The present invention has been made based on such findings.

1. 1. Recording medium The recording medium of the present invention has a film base material and a processing layer.

1-1. Film substrate The film substrate is preferably one that is non-absorbent or slightly absorbent. Examples of resins constituting the film substrate include polyesters such as polyethylene terephthalate and polyethylene naphthalate, polyolefins such as polyethylene and polypropylene, polyamides such as nylon, polystyrene, polyvinyl alcohol, polyvinyl chloride, polycarbonate, polyacrylonitrile, and polylactic acid. Examples thereof include biodegradable resins such as. In particular, polyolefin films, polyethylene films, nylon films and the like are preferable.

The film substrate may be either an unstretched film or a stretched film, and is preferably a stretched film stretched in the uniaxial or biaxial direction.

The film substrate may be subjected to surface treatment such as corona discharge treatment, ozone treatment, low temperature plasma treatment, frame treatment, and glow discharge treatment. In particular, from the viewpoint of facilitating the adhesion and lamination strength of the curing agent contained in the treated layer, the surface of the film substrate is preferably treated with a corona discharge treatment. The wetting tension of the corona-treated film surface is preferably 45 to 70 mN / m, more preferably 50 to 60 mN / m. Further, the film base material may be subjected to antistatic processing or anti-fog processing.

1-2. Treated layer The treated layer contains a water-soluble resin having a functional group that reacts with the curing agent, a curing agent, and if necessary, further contains a compound that further aggregates the coloring material and a water-dispersible resin.

1-2-1. Water-soluble resin that reacts with the curing agent A water-soluble resin having a functional group that reacts with the curing agent (hereinafter, also simply referred to as “water-soluble resin”) is a resin that is soluble in water and has a functional group that reacts with the curing agent. It is different from the water-dispersible resin (so-called dispersion or emulsion) dispersed in water in the form of fine particles by an emulsifier or a polar functional group as described later.

Examples of functional groups that can react with the curing agent include carboxyl groups, hydroxyl groups, carbonyl groups, amino groups, acetoxy groups, silanol groups and the like. Of these, a carboxyl group, a hydroxyl group and an amino group are preferable because they have good reactivity with a curing agent.

The water-soluble resin having a functional group that reacts with the curing agent is not particularly limited, and examples thereof include polyvinyl alcohol, poly (meth) acrylic acid ester, polyvinylpyrrolidone, polyvinylpyridinium halide, polyacrylamide, polydimethylacrylamide, and poly. Dimethylaminoacrylate, polyacrylic acid salt, acrylate copolymer salt of acrylate, sodium polymethacrylate, starch, oxidized starch, carboxyl starch, dialdehyde starch, cationized starch, dextrin, sodium alginate, gum arabic, casein, purulan , Dextran, methyl cellulose, ethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, polyethylene glycol, polyethylene oxide, copolymer of polyethylene oxide and polypropylene oxide, polyvinyl ether, polyglycerin, alkyl vinyl ether copolymer of maleic acid, maleic acid-N-vinyl Pyrol copolymer, styrene-maleic anhydride copolymer, polyallylamines, polyamines, dicyandiamide-based condensates, polyethyleneimine, allylamine / maleic acid copolymer, diallylamine hydrochloride / maleic acid copolymer, methyldiallylamine ・Maleic acid copolymers, diallyldimethylammonium chloride maleic acid copolymers, and derivatives thereof are included.

As will be described later, the treated layer may further contain a compound that aggregates the coloring material. Since the compound that aggregates the coloring material is often a cationic compound, the ionicity of the water-soluble resin having a functional group that reacts with the curing agent is nonionic, from the viewpoint of facilitating compatibility with the cationic compound. It is preferably cationic or amphoteric.

As the nonionic water-soluble resin having a functional group that reacts with the curing agent, polyvinyl alcohol is preferable, and a partially saponified polyvinyl alcohol is preferable from the viewpoint of the balance between flexibility and water solubility. Further, in order to enhance the reactivity with the curing agent, polyvinyl alcohol modified with a reactive group such as an acetoacetyl group can also be preferably used.

As the cationic water-soluble resin having a functional group that reacts with the curing agent, polyamines and polyallylamines having 1st to 3rd grade amines in their structures can be preferably used. For example, PAS series and PAA series manufactured by Nitto Boseki Chemical Co., Ltd. can be used.

As the amphoteric water-soluble resin having a functional group that reacts with the curing agent, a water-soluble resin having a carboxyl group as a negative component and an amine or a quaternary ammonium salt as a positive component can be preferably used. For example, an allylamine / maleic acid copolymer, a diallylamine hydrochloride / maleic acid copolymer, a methyldiallylamine / maleic acid copolymer, a diallyldimethylammonium chloride maleic acid copolymer, etc. manufactured by Nitto Boseki Chemical Co., Ltd. may be used. Can be done.

The content of the structural unit having a functional group (functional group-containing structural unit) in the water-soluble resin having a functional group that reacts with the curing agent is 0.5 to 10 mol with respect to all the structural units constituting the water-soluble resin. %, More preferably 1-5 mol%. The content of the functional group-containing structural unit can be specified by the charging ratio at the time of synthesizing the water-soluble resin, ¹³ C-NMR measurement, ¹ H-NMR measurement, or the like.

A part of the water-soluble resin having a functional group that reacts with the curing agent contained in the treated layer may react with the curing agent to form a cured product. As the water-soluble resin having a functional group that reacts with the curing agent, only one kind may be used, or two or more kinds may be used in combination.

The content of the water-soluble resin having a functional group that reacts with the curing agent is preferably 10% by mass or more and 95% by mass or less, and 20% by mass or more and 90% by mass or less with respect to the total mass of the treated layer. Is more preferable. When the content of the water-soluble resin is 10% by mass or more, bleeding of the ink when the ink is applied onto the treated layer is sufficiently suppressed, and the adhesion of the image is easily improved, which is 95% by mass or less. And, curl due to expansion and contraction is unlikely to occur.

Further, the treated layer may further contain a water-soluble resin having no functional group that reacts with the curing agent, if necessary.

1-2-2. Curing agent The curing agent is not particularly limited as long as it can covalently or ionic bond with a water-soluble resin having a functional group that reacts with the curing agent.

When the functional group in the water-soluble resin having a functional group that reacts with the curing agent is a hydroxyl group, an isocyanate-based curing agent or a methylol-based curing agent can be used. When the functional group in the water-soluble resin having a functional group that reacts with the curing agent is a carboxyl group, an epoxy-based curing agent, an aziridine-based curing agent, an oxazoline-based curing agent, a methylol-based curing agent, a carbodiimide-based curing agent or a metal chelate. A system curing agent can be used. When the functional group in the water-soluble resin having a functional group that reacts with the curing agent is a carbonyl group, a hydrazine-based curing agent can be used. When the functional group in the water-soluble resin having a functional group that reacts with the curing agent is an amino group, an isocyanate-based curing agent or an epoxy-based curing agent can be used. When the functional group in the water-soluble resin having a functional group that reacts with the curing agent is an acetoxy group, an amine-based curing agent, a methylol-based curing agent, or a metal chelate-based curing agent can be used. When the functional group in the water-soluble resin having a functional group that reacts with the curing agent is a silanol group, a silanol-based curing agent can be used.

Among them, a preferable example of a combination of a water-soluble resin having a functional group that reacts with a curing agent and a curing agent is a combination of a water-soluble resin having a hydroxyl group and an isocyanate-based curing agent; a water-soluble resin having a carboxyl group and a carbodiimide. Includes a system curing agent or a combination with an oxazoline-based curing agent.

The isocyanate-based curing agent is a compound having an isocyanate group, and is a water-dispersible isocyanate in which the isocyanate is protected by a hydrophilic outer layer due to a core-shell structure or the like to improve storage stability, or an isocyanate is used as a heat-dissociable blocking agent. It can be a protected blocked isocyanate. Examples of water-dispersible isocyanates include Takenate WD series manufactured by Mitsui Chemicals, Duranate series manufactured by Asahi Kasei Corporation, and Barnock series manufactured by DIC Corporation. Examples of blocked isocyanates include Baxenden's Aqua BI200, Aqua BI220 and the like.

The carbodiimide-based curing agent is a compound having a carbodiimide group, and examples thereof include polycarbodiimide, dicyclohexylcarposiimide, and diisopropylcarposiimide. Examples of commercially available products include carbodilite manufactured by Nisshinbo Chemical Co., Ltd.

The oxazoline-based curing agent is a compound having an oxazoline group, and examples thereof include an oxazoline group-containing polymer. Examples of commercially available products include the Epocross series manufactured by Nippon Shokubai Co., Ltd.

The curing agent may be used alone or in combination of two or more.

The content of the curing agent is preferably 0.5% by mass or more and 20% by mass or less, and more preferably 2% by mass or more and 10% by mass or less with respect to the total mass of the water-soluble resin. When the content of the curing agent is 0.5% by mass or more, the water-soluble resin can be sufficiently cured, so that it is easier to further improve the adhesion of the image, and when it is 20% by mass or less, it depends on the unreacted curing agent. It is easy to suppress bleed-out.

1-2-3. The compound treatment layer that agglomerates the coloring material preferably further contains a compound that agglomerates the coloring material contained in the applied ink (hereinafter, also referred to as an aggregating agent). As a result, bleeding that occurs especially when inkjet recording is performed at high speed can be suppressed more effectively. In particular, when a water-based inkjet ink is used, it is preferable to use a water-soluble flocculant. This is because the water-soluble flocculant is presumed to have a high diffusion rate in the vicinity of the coloring material.

When the coloring material contained in the ink is an anionic dye or pigment, for example, an acid or a cationic compound can be preferably used as the flocculant.

The acid can aggregate anionic colorants in the ink due to pH fluctuations. Examples of such acids include formic acid, acetic acid, propionic acid, isobutyric acid, oxalic acid, fumaric acid, malic acid, citric acid, malonic acid, succinic acid, maleic acid, benzoic acid, 2-pyrrolidone-5-carboxylic acid. Includes acids, lactic acids, malic acid or its derivatives, methacrylic acid or its derivatives, acrylamide or its derivatives, sulfonic acid derivatives, phosphoric acid or its derivatives. As the acid, an organic acid can be preferably used rather than an inorganic acid. By using an organic acid, compatibility with other components in the treatment liquid can be improved, and since it does not easily become a salt in the obtained treatment layer, an effect of excellent transparency can be obtained.

The cationic compound can be a polyvalent metal salt, a cationic surfactant, a cationic resin, or the like. Examples of polyvalent metal salts include water-soluble salts such as calcium salts (calcium chloride dihydrate and the like), magnesium salts, aluminum salts, zinc salts and the like. Examples of cationic surfactants (also referred to as cationic surfactants) include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts and the like. Is done. Examples of cationic resins include polyallylamine, polyvinylamine, polyethyleneimine, polydiallyldimethylammonium chloride and the like.

Above all, the flocculant is preferably a polyvalent metal salt from the viewpoint that the adhesiveness of the curing agent and the effect of improving the laminating strength can be easily obtained.

As the flocculant, one type may be used alone, or a plurality of types may be used in combination.

In the case of a polyvalent metal salt, the content of the flocculant is preferably 3% by mass or more and 60% by mass or less with respect to the total mass of the treated layer. When the content of the flocculant is 3% by mass or more, bleeding is more easily suppressed, and when it is 60% by mass or less, the curability at the time of laminating is not easily impaired. The acid content may be such that the treatment liquid is less than pKa.

1-2-4. Water-dispersible resin A water-dispersible resin (hereinafter, also simply referred to as “resin fine particles”) is a resin that can be dispersed in water in the form of fine particles to form a dispersion or an emulsion.

Examples of water-dispersible resins include acrylic resins, polyvinyl acetate resins, polyvinylpyrrolidone resins, polyurethane resins, alkyd resins, polyester resins, polyvinyl chloride resins, polyolefin resins, and polyether resins. , Polybutadiene-based resin, polystyrene-based resin, etc. are included. Of these, acrylic resins, polyvinyl acetate resins, polyurethane resins, and polyolefin resins are preferable, and polyurethane resins are more preferable.

The water-dispersible resin preferably has a functional group that can react with the curing agent. That is, the water-dispersible resin is a water-dispersible resin having a functional group capable of reacting with the curing agent in the structure, or a water-dispersible resin dispersed with an emulsifier having a functional group capable of reacting with the curing agent. It is preferable to have. Examples of such functional groups include those similar to those described above. Of these, a carboxyl group, a hydroxyl group, and an amino group are preferable. From the viewpoint of enhancing the compatibility with the compound that aggregates the coloring material (cationic compound), the ionicity of the water-dispersible resin having a functional group that reacts with the curing agent is cationic, nonionic or amphoteric. Is preferable.

Examples of the cationic water-dispersible resin having a functional group that reacts with the curing agent include a water-dispersible resin having a 1st to 3rd grade amino group in the structure. For example, the cationic urethane resin can be a polymer obtained by reacting a polyisocyanate component with a polyol component containing a polyol having a 1st to 3rd amino group. Examples of the polyol having a 1st to 3rd secondary amino group include N-methyl-diethanolamine, a polyol obtained by reacting a compound having two epoxies with a secondary amine, and the like. For example, Superflex 620 (cationic polyurethane emulsion) manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. can be used.

Examples of the nonionic water-dispersible resin having a functional group that reacts with the curing agent include a water-dispersible resin having an alkylene oxide group such as an ethylene oxide group and a propylene oxide group. For example, Aquabrid 4790 manufactured by Daicel FineChem Co., Ltd. can be used.

As the amphoteric water-dispersible resin having a functional group that reacts with the curing agent, a water-dispersible resin having a carboxyl group as a negative component and an amine or a quaternary ammonium salt as a positive component can be preferably used. For example, AKW-107 manufactured by Taisei Fine Chemical Co., Ltd. can be used.

The content of the structural unit having a functional group (functional group-containing structural unit) in the water-dispersible resin having a functional group that reacts with the curing agent is 0.2 to 0.2 with respect to all the structural units constituting the water-dispersible resin. It is preferably 40% by mass, more preferably 0.5 to 15% by mass. The content of the functional group-containing structural unit can be specified by the same method as described above.

The content of the water-dispersible resin is preferably 2% by mass or more and 80% by mass or less, and more preferably 5% by mass or more and 50% by mass or less with respect to the total mass of the treated layer. When the content of the water-dispersible resin is 2% by mass or more, the bleeding of the ink when the ink is applied on the treated layer is further suppressed, and the adhesion of the image is more easily improved, and the content is 80% by mass or less. If there is, the haze of the recording medium is unlikely to increase.

The content ratio of the water-dispersible resin to the water-soluble resin can be water-dispersible resin / water-soluble resin = 10/90 to 60/40 (mass ratio). When the content ratio of the water-dispersible resin is high, not only the water resistance of the obtained image is easily improved, but also the adhesion and the laminating strength of the image are easily improved, and when the content ratio of the water-soluble resin is high, bleeding is suppressed. Cheap.

1-2-5. Other Ingredients The treated layer may further contain other ingredients such as surfactants, cross-linking agents, fungicides, fungicides, etc., as long as the effects of the present invention are not impaired.

1-2-6. Physical characteristics of the treated layer The thickness of the treated layer is 0.3 μm or more and 3.0 μm or less. When the thickness of the treated layer is 0.3 μm or more, it is possible to improve the adhesion of the image and the lamination strength while suppressing the bleeding of the ink. When the thickness of the treated layer is 3.0 μm or less, the deformation stress due to moisture and heat can be reduced, so that the adhesion of the image and the laminating strength are not easily impaired. The thickness of the treated layer is more preferably 0.5 μm or more and 2 μm or less.

1-2-6. Physical characteristics of the treated layer The amount of the water-soluble resin extracted from the treated layer when the recording medium is immersed in water at 40 ° C. for 1 hour is 0.1 g / m ² or more and 2.0 g / m ² or less, preferably 0.1 g / m 2 or more. It is 0.3 g / m ² or more and 1.0 g / m ² or less. When the amount of the water-soluble resin to be extracted is 0.1 g / m ² or more, the water-soluble resin in the treated layer is not over-cured, and therefore, when the ink is applied, the water-soluble resin is contained in the ink. It is easy to elute and diffuse, the ink can be thickened, and the ink bleeding can be suppressed. On the other hand, when the amount of the water-soluble resin to be extracted is 2.0 g / m ² or less, the water-soluble resin in the treated layer is appropriately cured, so that the swelling stress due to the applied ink does not become too large. Therefore, the adhesion of the image and the laminating strength are not easily impaired.

The amount of the water-soluble resin extracted from the treatment layer when the recording medium is immersed in water at 40 ° C. for 1 hour can be measured using a GC-MS (gas chromatograph-mass spectrometer). That is, the amount of the water-soluble resin extracted when the recording medium is immersed in water at 40 ° C. for 1 hour, and the water-soluble resin extracted from the treatment layer when the film substrate is immersed in water at 40 ° C. for 1 hour. By measuring the amount of the sex resin and taking the difference between them, the amount of the water-soluble resin extracted from the treated layer can be measured. The measurement conditions are the same as in the examples described later.

As described above, since the water-soluble resin in the treated layer is not over-cured in the recording medium, the water-soluble resin in the treated layer can be eluted into the ink when the ink is applied to the treated layer. .. As a result, the ink can be appropriately thickened, so that bleeding of the ink can be suppressed.

The amount of the water-soluble resin extracted from the treatment layer when the recording medium is immersed in water at 40 ° C. for 1 hour is the composition of the treatment layer (mainly the resin composition), the thickness, and the drying conditions in the treatment liquid drying step described later. It can be adjusted by (temperature, time) and so on. In order to increase the amount of the water-soluble resin extracted from the treatment layer when the recording medium is immersed in water at 40 ° C. for 1 hour, for example, the water-dispersible resin may not be added to the treatment layer, or the treatment layer may not be added. The thickness may be increased, or the drying time in the treatment liquid drying step may be shortened (for example, the ink drying step may have only the high temperature drying step and not the low temperature drying step).

1-3. Method for Producing Recording Medium The method for producing a recording medium of the present invention is as follows: 1) a treatment liquid applying step of applying a treatment liquid containing at least a water-soluble resin, a curing agent, and water to a film substrate, and 2). It has a treatment liquid drying step of drying the applied treatment liquid.

1-3-1. Treatment liquid application step A treatment liquid containing at least the above-mentioned water-soluble resin, a curing agent, and water is applied onto the film substrate.

The content of the water-soluble resin in the treatment liquid may be set so that the content of the water-soluble resin in the treatment layer is within the above range. For example, the content of the water-soluble resin is preferably 5% by mass or more and 40% by mass or less, and more preferably 10% by mass or more and 30% by mass or less with respect to the total mass of the treatment liquid.

It is preferable to add the curing agent to the treatment liquid immediately before applying the treatment liquid to the film substrate from the viewpoint of facilitating the stable effect of curing. The content of the curing agent in the treatment liquid may be set so that the content of the curing agent in the treatment layer is within the above range.

The treatment liquid may further contain an organic solvent in addition to water as a solvent, if necessary. Further, the treatment liquid may further contain a surfactant, an antifungal agent, a bactericide and the like as long as the effects of the present invention are not impaired.

The method for applying the treatment liquid onto the film substrate is not particularly limited, and examples thereof include a roller coating method, a curtain coating method, a spray coating method, and an inkjet method.

1-3-2. Treatment liquid drying step Next, the treatment liquid applied to the film substrate is dried.

It is preferable that the treatment liquid is dried to such an extent that the water-soluble resin is not completely cured while evaporating and removing water or the like, which is a solvent component of the treatment liquid. That is, in this step, the treated layer is kept in a state (incompletely cured state) in which there is room for further progress of film formation. The incompletely cured state is specifically a state in which the water-soluble resin is not completely cured by heating and is in an uncured state, or even if a part of the water-soluble resin is cured, it is water-soluble. All of the sex resin is not cured. In such an incompletely cured treatment layer, when the ink is applied, the water-soluble resin is likely to elute into the ink, so that the ink is easily thickened and bleeding is easily suppressed.

It is also preferable to further heat and store the treatment liquid after it has dried. As a result, it is easy to fine-tune the cured state of the water-soluble resin contained in the treatment liquid, so that it is easy to fine-tune the amount of the water-soluble resin eluted from the treatment layer into the ink when the ink is applied. can.

Specifically, in the drying and heat storage of the treatment liquid, the amount of the water-soluble resin extracted from the treatment layer when the obtained recording medium is immersed in water at 40 ° C. for 1 hour is 0.1 g / m ² or more 2 Perform under conditions (temperature, time) such that it is 0.0 g / m ^{2 or less.} Such drying and heat storage conditions may be lower temperature or shorter time conditions than conditions under which the water-soluble resin is completely cured.

The drying temperature (first drying temperature) of the treatment liquid is preferably, for example, 40 ° C. or higher, and more preferably 40 ° C. or higher and 100 ° C. or lower. The drying time of the treatment liquid depends on the drying temperature of the treatment liquid (first drying temperature), but is preferably 3 seconds or more and 60 seconds or less, for example.

The heating temperature (first heating temperature) is preferably 40 ° C. or higher and 120 ° C. or lower, and the heating storage time is preferably 0.5 hours or more and 30 hours or less, although it depends on the heating temperature. The heating temperature (first heating temperature) may be lower than the drying temperature (first drying temperature).

The treatment liquid may be dried and stored by heating using a non-contact heating type drying device such as a drying oven or a hot air blower, or a contact heating type drying such as a hot plate or a hot roller. It may be done using a device.

The drying temperature and heating temperature are (a) an atmospheric temperature such as the temperature inside the furnace or the temperature of hot air when a non-contact heating type drying device such as a drying furnace or a hot air blower is used, and (b) a hot plate. When a contact heating type drying device such as a heat roller or a heat roller is used, any one selected from the temperature of the contact heating part or (c) the surface temperature of the surface to be dried is used for all the drying of the treatment liquid. It can be obtained by measuring during the period, and it is more preferable to measure (c) the surface temperature of the surface to be dried as the measurement location.

2. 2. Image Forming Method The image forming method of the present invention comprises 1) an inkjet recording medium preparation step for preparing the above-mentioned inkjet recording medium, and 2) an ink containing at least a coloring material and water on the inkjet recording medium. It has an ink applying step of applying the ink by an inkjet method and 3) an ink drying step of drying the applied ink.

2-1. Recording medium preparation step The above-mentioned inkjet recording medium is the above-mentioned 1-3. It can be manufactured by the same method as that of the recording medium.

2-2. About the ink applying step Next, an ink containing at least a coloring material and water is applied onto the processing layer of the recording medium by an inkjet method. The ink used in this step will be described later.

2-3. About the ink drying step Next, the ink applied on the processing layer is dried.

Drying the ink mainly evaporates and removes water and organic solvents, which are solvent components of the ink, and promotes the elution of the water-soluble resin from the treatment layer to the ink, so that the water-soluble resin eluted in the ink is sufficiently removed. It is preferable to carry out to the extent that it is cured. Specifically, the water-soluble resin in the treated layer and the water-soluble resin eluted in the ink are completely cured or cured to a state close to that. As a result, the adhesion of the image formed by the ink can be enhanced, and further, the laminating strength when the film is laminated (thermocompression bonding) can be enhanced.

In terms of achieving both elution and curing of the water-soluble resin, it is also preferable to further heat and store the ink after it has dried. Thereby, when the ink is applied, the amount of the water-soluble resin eluted from the treatment layer into the ink can be finely adjusted.

Specifically, in drying and heat storage, the total amount of water-soluble resin extracted from the treated layer and the image-forming layer when the image-forming product is immersed in water at 40 ° C. for 1 hour is less than ^{0.1 g / m 2.} More preferably, it is carried out under conditions (temperature, time) such that it is less than 0.04 g / m ^2. When the amount of the water-soluble resin extracted is ^{less than 0.1 g / m 2} , the water-soluble resin eluted in the ink is sufficiently cured, so that the lamination strength can be further increased.

The drying temperature (second drying temperature) of the ink is preferably, for example, 40 ° C. or higher, and more preferably 40 ° C. or higher and 100 ° C. or lower. The drying time of the ink depends on the drying temperature of the ink, but is preferably 3 seconds or more and 60 seconds or less, for example.

The heating temperature (second heating temperature) of the ink is preferably 40 ° C. or higher and 120 ° C. or lower, and the heating time is preferably 0.5 hours or longer and 30 hours or lower, although it depends on the heating temperature. .. The heating temperature (second heating temperature) may be lower than the drying temperature (second drying temperature).

The ink can be dried and stored by heating in the same manner as the above-mentioned drying and heat storage of the treatment liquid. Further, the drying temperature and the heating temperature of the ink can be measured in the same manner as the drying temperature and the heating temperature in the above-mentioned processing liquid drying step, and unless there are special circumstances, the drying temperature and the heating in the treatment liquid drying step can be measured. Use the values measured under the same conditions as the temperature measurement conditions.

It is preferable that the water-soluble resin eluted in the ink is sufficiently cured in the obtained image-forming product. Specifically, as described above, the total amount of the water-soluble resin extracted from the treated layer and the image-forming layer when the image-forming product is immersed in water at 40 ° C. for 1 hour is less than ^{0.1 g / m 2.} Is preferable, and more preferably less than ^{0.01 g / m 2.}

The total amount of the water-soluble resin extracted from the treatment layer and the image-forming layer when the image-forming product is immersed in water at 40 ° C. for 1 hour can be measured by the same method as described above (GC-MS). That is, the total amount of the water-soluble resin extracted when the image-forming material (the processing layer and the recording medium having the image-forming layer) is immersed in water at 40 ° C. for 1 hour, and the film substrate is 1 in water at 40 ° C. By measuring the amount of the water-soluble resin extracted when immersed for a time and taking the difference between them, the total amount of the water-soluble resin extracted from the treated layer and the image forming layer can be measured.

The total amount of the water-soluble resin extracted from the treatment layer and the image-forming layer when the image-forming product is immersed in water at 40 ° C. for 1 hour is the composition of the treatment layer (mainly the resin composition), the drying of the treatment liquid drying step, and the drying of the treatment liquid. It can be adjusted according to the heat storage conditions (temperature, time), the drying of the ink drying step, and the heat storage conditions (temperature, time). In order to reduce the amount of the water-soluble resin extracted from the treatment layer and the image forming layer when the recording medium is immersed in water at 40 ° C. for 1 hour, for example, a water-dispersible resin may be added to the treatment layer or the treatment may be performed. The drying and heating time of the liquid drying step and the ink drying step may be lengthened (for example, the treatment liquid drying step and the ink drying step may be performed not only for drying but also for heat storage).

As described above, in the present invention, in the treatment liquid drying step, drying (further heat storage if necessary) is performed under conditions that the water-soluble resin in the treatment liquid is not completely cured. That is, the treatment liquid is dried so that the amount of the water-soluble resin extracted from the treatment layer when the recording medium is immersed in water at 40 ° C. for 1 hour is 0.1 g / m ² or more and 2.0 g / m ^{2 or less.} Adjust the drying and heat storage conditions (temperature, time) of the process. As a result, the water-soluble resin can be in a state of not being completely cured (incompletely cured state) while removing solvent components such as water contained in the treated layer. It is presumed that the ink applied by the inkjet method easily penetrates into such a treated layer, and bleeding between the applied inks is prevented. In particular, even in the single-pass method in which ink is applied at high speed, bleeding can be suppressed because the ink permeates the processing layer quickly.

On the other hand, in the ink drying step after applying the ink to the treated layer, it is preferable to perform drying (further heat storage if necessary) under conditions that the water-soluble resin eluted in the ink is sufficiently cured. That is, the ink drying step is dried so that the total amount of the water-soluble resin extracted from the treatment layer and the image-forming layer is ^{less than 0.1 g / m 2 when the image-forming product is immersed in water at 40 ° C. for 1 hour.} And it is preferable to adjust the heat storage conditions (temperature, time). As a result, the movement of the water-soluble resin in the treated layer to the ink is promoted, and the water-soluble resin easily moves to the vicinity of the coloring material. Further, since the water-soluble resin can react with the curing agent and be sufficiently cured, it is presumed that the adhesion of the image and the laminating strength are enhanced.

Thereby, it is possible to improve the adhesion and the laminating strength while preventing the blurring of the image.

Next, the ink applied on the processing layer in the ink application step will be described in detail.

As mentioned above, the ink contains at least a colorant and water.

As the coloring material, for example, dyes, pigments or mixtures thereof can be used.

Examples of the dye include water-soluble dyes and disperse dyes. Examples of the water-soluble dye include acid dyes, direct dyes, and basic dyes. Examples of the disperse dye include colored polymers and colored waxes.

As the pigment, conventionally known pigments can be used without particular limitation, and any of water-dispersible pigments, solvent-dispersible pigments and the like can be used. For example, organic pigments such as insoluble pigments and lake pigments, or titanium oxide and carbon black can be used. And other inorganic pigments can be preferably used. These pigments can be used in a state of being dispersed in the ink by, for example, a pigment dispersant.

The insoluble pigment is not particularly limited, and is, for example, azo, azomethine, methine, diphenylmethane, triphenylmethane, quinacridone, anthraquinone, perylene, indigo, quinophthalone, isoindolinone, isoindoline, azine, oxazine, thiazine, dioxazine, thiazole, and the like. Phthalocyanine, diketopyrrolopyrrole and the like are preferable.

The organic pigment is not particularly limited, but for example, the following can be preferably exemplified.

Examples of the pigment used for yellow or orange include C.I. I. Pigment Orange 31, C.I. I. Pigment Orange 43, C.I. I. Pigment Yellow 12, C.I. I. Pigment Yellow 13, C.I. I. Pigment Yellow 14, C.I. I. Pigment Yellow 15, C.I. I. Pigment Yellow 15: 3, C.I. I. Pigment Yellow 17, C.I. I. Pigment Yellow 74, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 128, C.I. I. Pigment Yellow 94, C.I. I. Pigment Yellow 138, C.I. I. Pigment Yellow 155 and the like.

Examples of the pigment used for magenta or red include C.I. I. Pigment Red 2, C.I. I. Pigment Red 3, C.I. I. Pigment Red 5, C.I. I. Pigment Red 6, C.I. I. Pigment Red 7, C.I. I. Pigment Red 15, C.I. I. Pigment Red 16, C.I. I. Pigment Red 48: 1, C.I. I. Pigment Red 53: 1, C.I. I. Pigment Red 57: 1, C.I. I. Pigment Red 122, C.I. I. Pigment Red 123, C.I. I. Pigment Red 139, C.I. I. Pigment Red 144, C.I. I. Pigment Red 149, C.I. I. Pigment Red 166, C.I. I. Pigment Red 177, C.I. I. Pigment Red 178, C.I. I. Pigment Red 202, C.I. I. Pigment Red 222, C.I. I. Pigment Violet 19 and the like.

Examples of the pigment used for cyan or green include C.I. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15: 3, C.I. I. Pigment Blue 16, C.I. I. Pigment Blue 60, C.I. I. Pigment Green 7 and the like.

Examples of the pigment used for black and the like include C.I. I. Pigment Black 1, C.I. I. Pigment Black 6, C.I. I. Pigment Black 7 and the like.

The average particle size of the dispersed state of the pigment in the ink is preferably in the range of 50 nm to 200 nm. As a result, the dispersion stability of the pigment can be improved, and the storage stability of the ink can be improved. The particle size of the pigment can be measured by a commercially available particle size measuring device using a dynamic light scattering method, an electrophoresis method, etc., but the measurement by the dynamic light scattering method is simple and the particle size region can be measured. It can be measured accurately.

The pigment can be dispersed and used by a disperser together with a pigment dispersant and other additives necessary for various purposes.

As the disperser, a conventionally known ball mill, sand mill, line mill, high-pressure homogenizer, or the like can be used. Above all, it is preferable to disperse the pigment by a sand mill because the particle size distribution becomes sharp. The material of the beads used for the sand mill dispersion is not particularly limited, but is preferably zirconia or zircon from the viewpoint of preventing the formation of bead fragments and the contamination of ionic components. Further, the bead diameter is preferably 0.3 mm to 3 mm.

The content of the pigment in the ink is not particularly limited, but is preferably in the range of 7 to 18% by mass for the inorganic pigment and preferably in the range of 0.5 to 7% by mass for the organic pigment. ..

It is particularly preferable to use an anionic dispersed pigment as the pigment. Examples of the anionic dispersed pigment include a pigment having an anionic group introduced on the surface and a pigment dispersed by a pigment dispersant having an anionic group.

As the anionic group, a carboxyl group, a sulfonic acid group and the like can be preferably exemplified.

Further, the anionic group is preferably alkali-neutralized. Examples of the alkali that neutralizes the anionic group include metal base compounds such as sodium hydroxide, potassium hydroxide, lithium hydroxide, and calcium hydroxide, organic amines such as ammonia, triethylamine, pyridine, and morpholine, and monoethanol. Alkanolamines such as amines can be preferably mentioned.

As the pigment dispersant, a polymer dispersant having an acid value (also referred to as a resin dispersant) can be preferably used. The acid value is not particularly limited, but is preferably in the range of 50 mgKOH / g or more and 250 mgKOH / g or less.

As the pigment dispersant, for example, an acrylic dispersant can be preferably used. As the acrylic dispersant, one or more kinds selected from poly (meth) acrylic acid and (meth) acrylic acid copolymer can be preferably used.

The acrylic dispersant contains (meth) acrylic acid as a monomer component. As the acrylic dispersant, a polymer of (meth) acrylic acid (that is, poly (meth) acrylic acid) or, if necessary, a copolymer obtained by copolymerizing other monomer components such as styrene (that is, (meth)). Acrylic acid copolymer) can be preferably used.

Examples of the acrylic dispersant include "John Krill 819" (acid value 75 mgKOH / g), "John Krill 67" (acid value 213 mgKOH / g), "John Krill 678" (acid value 215 mgKOH / g) manufactured by BASF, etc. Commercially available products can be used.

As the pigment dispersant, one type may be used alone, or a plurality of types may be used in combination.

As the organic solvent contained in the ink, for example, a water-soluble organic solvent can be preferably used.

As the water-soluble organic solvent, for example, monohydric alcohols, glycols (dihydric alcohols), trihydric alcohols, glycol ethers, acetates, amines, amides and the like can be preferably mentioned.

As the monohydric alcohols, for example, methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol, tertiary butanol and the like can be preferably mentioned.

Examples of glycols include ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene glycol having 5 or more ethylene oxide groups, propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol, and propylene oxide groups. Polypylene glycol, butylene glycol, thiodiglycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,2-hexanediol , 1,2-Heptanediol, 3-methyl-2,4-pentanediol and the like can be preferably mentioned.

As the trihydric alcohols, for example, glycerin, hexanetriol and the like can be preferably mentioned.

Examples of glycol ethers include ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol monopropyl ether, diethylene glycol monobutyl ether, triethylene glycol monomethyl ether, and triethylene glycol monoethyl ether. Triethylene glycol monopropyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monomethyl ether, tetraethylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monoethyl ether, Dipropylene Glycol Monopropyl Ether, Tripropylene Glycol Monomethyl Ether, Tripropylene Glycol Monoethyl Ether, Tripropylene Glycol Monopropyl Ether, Tripropylene Glycol Monobutyl Ether, Tetrapropylene Glycol Monomethyl Ether, Diethylene Glycol Diethyl Ether, Diethylene Glycol Dibutyl Ether, Triethylene Glycol Preferred examples thereof include diethyl ether, triethylene glycol dibutyl ether, dipropylene glycol dibutyl ether, and tripropylene glycol dibutyl ether.

As the acetates, for example, ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol diacetate, diethylene glycol monoethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol diacetate and the like can be preferably mentioned.

Examples of amines include ethanolamine, diethanolamine, triethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, morpholine, N-ethylmorpholine, ethylenediamine, diethylenediamine, triethylenetetramine, tetraethylenepentamine, polyethyleneimine, and the like. Pentamethyldiethylenetriamine, tetramethylpropylenediamine and the like can be preferably mentioned.

As the amides, for example, 2-pyrrolidinone, dimethylimidazolidinone, formamide, N, N-dimethylformamide, N, N-dimethylacetamide and the like can be preferably mentioned.

These solvents may be used alone or in combination of two or more. In particular, when the resin contained in the treated layer is a polyolefin resin, the most abundant solvent contained in the ink is preferably glycols, thereby suppressing the resin in the treated layer from swelling and dissolving more than necessary. , Good adhesion can be obtained. Here, the most abundant solvent contained in the ink refers to the solvent having the largest blending amount (mass base) in the ink if the ink contains a plurality of kinds of solvents, and the ink alone contains one kind of solvent. If it is contained in, it means the solvent.

The ink preferably contains a surfactant in order to improve the ejection property and the wettability. The surfactant is not particularly limited, and examples thereof include a cationic surfactant, an anionic surfactant, an amphoteric surfactant, and a nonionic surfactant.

Preferred examples of the cationic surfactant include aliphatic amine salts, aliphatic quaternary ammonium salts, benzalkonium salts, benzethonium chloride, pyridinium salts, and imidazolinium salts.

Examples of the anionic surfactant include fatty acid soap, N-acyl-N-methylglycine salt, N-acyl-N-methyl-β-alanine salt, N-acylglutamate salt, acylated peptide, and alkylsulphonic acid. Salt, alkylbenzene sulphonate, alkylnaphthalen sulphonate, dialkyl sulfosuccinate salt, alkyl sulfoacetate, α-olefin sulfonate, N-acylmethyl taurine, sulfated oil, higher alcohol sulphate ester salt, secondary Higher Alcohol Sulfate, Alkyl Ether Sulfate, Secondary Higher Alcohol ethoxysulfate, Polyoxyethylene Alkylphenyl Ether Sulfate, Monoglyculfate, Fatty Alkyrolamide Sulfate, Alkyl Ether Phosphate, Alkyl Phosphate Ester salts and the like can be preferably mentioned.

As the amphoteric tenside, for example, carboxybetaine type, sulfobetaine type, aminocarboxylate, imidazolinium betaine and the like can be preferably mentioned.

Examples of the nonionic surfactant include polyoxyethylene secondary alcohol ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene sterol ether, polyoxyethylene lanolin derivative, polyoxyethylene polyoxypropylene alkyl ether, and polyoxyethylene. Glycerin fatty acid ester, polyoxyethylene castor oil, hardened castor oil, polyoxyethylene sorbitol fatty acid ester, polyethylene glycol fatty acid ester, fatty acid monoglyceride, polyglycerin fatty acid ester, sorbitan fatty acid ester, propylene glycol fatty acid ester, sucrose fatty acid ester, fatty acid alkanol. Preferable examples include amides, polyoxyethylene fatty acid amides, polyoxyethylene alkylamines, alkylamine oxides, acetylene glycols, acetylene alcohols and the like.

From the viewpoint of lowering the surface tension, it is preferable that some of these surfactants are replaced with fluorine atoms or silicon atoms.

These surfactants may be used alone or in combination of two or more. The content of the surfactant in the ink is not particularly limited, but is preferably in the range of 0.1 to 5.0% by mass.

Other components can be appropriately blended in the ink as long as the effects of the present invention are not impaired.

The ink does not contain the water-dispersible resin described for the treatment liquid, or when it contains, it is 5% by mass or less, more preferably 3% by mass or less, and most preferably 2% by mass or less with respect to the ink mass. It is preferable to have. This has the effect of stabilizing the ink ejection characteristics in the inkjet method and satisfactorily preventing nozzle clogging.

The image-forming product obtained by the image-forming method of the present invention has high image adhesion and less elution of the water-soluble resin due to heat or water, and is therefore suitable for laminating applications.

3. 3. Method for Producing Film Laminate The method for producing a film laminate of the present invention is the above-mentioned image forming method, in which a step of forming an image forming layer on a recording medium for inkjet and an adhesive on the obtained image forming layer. It has a step of laminating a film via a layer.

The method for laminating the film is not particularly limited, and a generally used adhesive-applied dry laminating, extruded laminating using a molten resin, or the like can be preferably applied. In particular, in dry laminating suitable for retort and boiling applications, high laminating strength can be easily obtained by using the recording medium and image forming method of the present invention.

The dry laminating method includes a solvent type in which a two-component curable adhesive consisting of a polyol and polyisocyanate is diluted with an organic solvent, and the film is bonded and bonded after drying, and the adhesive is applied by controlling the viscosity by heating without using an organic solvent. There are so-called non-solvent type and water-based type in which an aqueous emulsion is applied and dried as an adhesive, and both are applicable. A solvent type and a non-solvent type can be particularly preferably applied to applications that require particularly strong adhesiveness.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

1. 1. Preparation of recording medium <Production of recording medium 1>
(1) Preparation of treatment liquid 1 While stirring 2,700 cc of ion-exchanged water at room temperature, polyvinyl alcohol (PVA) powder (PVA-217, degree of polymerization 1700, saponification degree 87-89%, stock) as a water-soluble resin. 240 g (manufactured by Kuraray Co., Ltd.) was gradually added. After the addition was completed, the temperature was raised to 95 ° C., and the mixture was stirred for 1 hour to dissolve. After cooling to room temperature, an amount of ion-exchanged water having a total amount of 3 kg was added and stirred to prepare an 8% by mass PVA aqueous solution.
To 62.5 parts by mass of the obtained PVA aqueous solution, 36.7 parts by mass of ion-exchanged water was added, the temperature was raised to 40 ° C., and the mixture was stirred. Immediately before coating on the film substrate, 0.8 parts by mass of water-dispersible isocyanate (Takenate WD-725, manufactured by Mitsui Chemicals, Inc.) was further added as a curing agent and stirred to obtain a treatment liquid 1.

(2) Preparation of Recording Medium 1 A biaxially stretched polyethylene terephthalate film (manufactured by Unitika Ltd., Embret PET-25, thickness 25 μm, wet tension 54 mN) obtained by corona-treating the obtained treatment liquid 1 as a film base material. / M) Using a wire bar, the coating film was applied so that the wet thickness of the coating film was 25 μm (treatment liquid application step). Next, the coating film was dried with warm air at 60 ° C. (first drying temperature) for 15 seconds to form a treated layer having a dry thickness of 1.3 μm, and a recording medium 1 was obtained. No heat storage was performed after the treatment liquid was dried.

<Preparation of recording media 2-7>
Recording media 2 to 7 were produced in the same manner as the recording medium 1 except that at least one of the drying thickness of the treated layer and the conditions of the treated layer drying step was changed as shown in Table 1.

<Preparation of recording medium 8>
(1) Preparation of Treatment Liquid 2 58.3 parts by mass of ion-exchanged water was added to 41.3 parts by mass of the PVA aqueous solution used for preparation of the treatment liquid 1, the temperature was raised to 40 ° C., and the mixture was stirred. Immediately before coating on the film substrate, 0.5 parts by mass of water-dispersible isocyanate (Takenate WD-725, manufactured by Mitsui Chemicals, Inc.) was further added as a curing agent and stirred to obtain a treatment liquid 2.

(2) Preparation of Recording Medium 8 The recording medium 8 was prepared in the same manner as the recording medium 1 except that the obtained treatment liquid 2 was applied so as to have a dry thickness of 0.2 μm.

<Preparation of recording medium 9>
(1) Preparation of Treatment Liquid 3 A treatment liquid 3 was obtained in the same manner as the treatment liquid 2 except that water-dispersible isocyanate (Takenate WD-725, manufactured by Mitsui Chemicals, Inc.) was not added as a curing agent.

(2) Preparation of Recording Medium 9 The recording medium 9 was prepared in the same manner as the recording medium 1 except that the obtained treatment liquid 3 was applied so as to have a dry thickness of 1.3 μm.

<Preparation of recording medium 10>
(1) Preparation of Treatment Liquid 4 Add 3.5 g of calcium chloride dihydrate as a flocculant to the treatment liquid 1 and adjust the amount of ion-exchanged water so that the total mass of the treatment liquid becomes 100 g. , The treatment liquid 4 was obtained.

(2) Preparation of Recording Medium 10 The recording medium 10 was prepared in the same manner as the recording medium 1 except that the obtained treatment liquid 4 was used.

<Preparation of recording medium 11>
(1) Preparation of treatment liquid 5 Superflex 620 (cationic polyurethane emulsion) manufactured by Daiichi Kogyo Seiyaku Co., Ltd. was further added to the treatment liquid 1 as resin fine particles so as to have a solid content of 5% by mass, and the entire treatment liquid was added. The treatment liquid 5 was obtained in the same manner as the treatment liquid 1 except that the amount of ion-exchanged water was adjusted so that the mass of the treatment liquid was 100 g.

(2) Preparation of Recording Medium 11 The recording medium 11 was prepared in the same manner as the recording medium 1 except that the obtained treatment liquid 5 was applied so as to have a dry thickness of 1.4 μm.

<Preparation of recording media 12 to 15>
(1) Preparation of Treatment Liquids 6 to 9 Treatment liquids 6 to 9 were obtained in the same manner as in the treatment liquid 5 except that the types of the water-soluble resin or the curing agent in the treatment liquid were changed as shown in Table 1.

(2) Preparation of Recording Media 12 to 15 Recording media 12 to 15 were prepared in the same manner as the recording medium 11 except that the obtained treatment liquids 6 to 9 were used.

The extraction amount of the water-soluble resin of the obtained recording media 1 to 15 was evaluated by the following method.

(Extraction amount of water-soluble resin)
When the obtained recording medium was immersed in water at 40 ° C. for 1 hour, the amount of water-soluble resin (PVA) eluted in the water was measured using a GC-MS (gas chromatograph-mass spectrometer). .. Further, for blank measurement, a water-soluble resin (PVA) eluted in water when a film substrate (biaxially stretched polyethylene terephthalate film recording medium treated with corona) was immersed in water at 40 ° C. for 1 hour. The amount of was also measured. Then, the latter was subtracted from the former to obtain the amount of the water-soluble resin extracted from the treated layer. The measurement conditions for GC-MS were as follows.

(GC-MS analysis)
Water after immersion was analyzed using a gas chromatograph device (Agilent 6890GC / 5973MSD manufactured by Agilent Technologies). The analysis conditions are as follows.
Column: DB-624 manufactured by J & W
Carrier gas: Helium Carrier gas flow rate: 0.7 ml / min
Injection port temperature: 160 ° C
Column temperature: 40 ° C (hold for 3 minutes) -20 ° C / min to raise temperature -230 ° C (hold for 8 minutes)
Detector: HP5793MSD

Table 1 shows the production conditions (composition of the treatment liquid / drying conditions of the treatment liquid) and the evaluation results (extraction amount of the water-soluble resin) of the obtained recording media 1 to 15. The abbreviations in the table indicate the following.
P-1: PVA-220 manufactured by Kuraray Co., Ltd. (partially saponified polyvinyl alcohol, degree of polymerization 2400)
P-2: PAS-2351 (diallyldimethylammonium chloride / maleic acid copolymer) manufactured by Nitto Boseki Chemical Co., Ltd.
P-3: PAS-21CL (diallylamine hydrochloride polymer) manufactured by Nitto Boseki Chemical Co., Ltd.
H-1: Takenate WD-725 (water-dispersible isocyanate) manufactured by Mitsui Chemicals, Inc.
H-2: Diethylene glycol diglycidyl ether H-3: Carbodilite V-04 (carbodiimide group-containing resin) manufactured by Nisshinbo Chemical Co., Ltd.
H-4: Epolite K-2020E (polymer containing oxazoline group) manufactured by Nippon Shokubai Co., Ltd.
A-1: Superflex 620 manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd. (cationic polyurethane emulsion)

2. 2. Ink preparation <Ink (I-1) preparation>
As a polymer dispersant, a styrene-acrylic acid copolymer (BASF's "John Krill 678", molecular weight 8500, acid value 215) 4.5% by mass, 25% ammonia aqueous solution 1.25% by mass, pigment (DIC) "GNKA-SD" manufactured by Pigment Blue 15: 3) A sand grinder filled with 0.5 mm zirconia beads at a volume ratio of 50% after premixing a mixed solution containing 15% by mass and ion-exchanged water as the balance. To obtain a cyan pigment dispersion (also simply referred to as a pigment dispersion) having a pigment content of 15% by mass. The average particle size of the pigment particles contained in this pigment dispersion measured by a dynamic light scattering method was 122 nm.

29.8% by mass of the obtained pigment dispersion, 15.0% by mass of ethylene glycol, 10.0 parts by mass of propylene glycol, 0.3% by mass of a silicone-based surfactant (KF-351A manufactured by Shin-Etsu Chemical Co., Ltd.), ions. The volume was adjusted to 100% by mass according to the amount of exchanged water (remaining portion), and the mixture was mixed and stirred. After stirring sufficiently, the ink (I-1) was obtained by filtering through a 5.0 μm filter. There was no substantial change in the composition of the ink before and after filtration.

<Preparation of ink (I-2)>
Pigment dispersion 29.8% by mass produced by ink (I-1), acrylic aqueous dispersion dispersion (JoncrylPDX-7667, manufactured by Johnson Polymer Co., Ltd., acid value 82, Tg75 ° C., solid content concentration) as an aqueous dispersible resin. 45%) 6.7% by mass, ethylene glycol 15.0% by mass, propylene glycol 10.0 parts by mass, silicone-based surfactant (manufactured by Shin-Etsu Chemical Industry Co., Ltd., KF-351A) 0.3% by mass, ion-exchanged water ( The amount was adjusted to 100% by mass according to the amount of the balance), and the mixture was mixed and stirred. After stirring sufficiently, the ink (I-2) was obtained by filtering through a 5.0 μm filter. There was no substantial change in the composition of the ink before and after filtration.

3. 3. Image formation by inkjet method <Test 1>
The ink (I-1) prepared above was applied onto the obtained treated layer by a single-pass method (one-pass printing) inkjet image forming method.
Specifically, two independently driven inkjet heads (360 dpi) manufactured by Konica Minolta are arranged side by side so that the nozzles are staggered, and two head modules capable of printing an image of 720 dpi x 720 dpi in a single pass method are prepared. Then, they were arranged side by side along the transport direction of the transport stage for transporting the recording medium. Each head module was installed so as to intersect the transport direction (movement axis of the transport stage). In this way, the ink ejection voltage was adjusted so that the printing rate of 200%, that is, the amount of ink applied for two colors (22.5 cc / m ^{2) could be printed when the recording medium was passed once.}

The recording medium 1 produced above is set on the transfer stage, and while the recording medium 1 is conveyed at a speed of 50 m / min and 5 m / min, respectively, an image is formed by a single pass method when the recording medium 1 passes under the head. (Ink applying step), the mixture was dried with warm air at 80 ° C. (second drying temperature) for 15 seconds. As an image, an image was formed in which characters having a size of 6 points were arranged as characters in a solid 7 cm square with an ink application amount of 22.5 cc / m ^2. The image formation by the inkjet method was continuously performed immediately after the production of the recording medium 1.

Further, the obtained image was further heated and stored at 40 ° C. (second heating temperature) for 24 hours to obtain an image-forming product.

<Tests 2-3, 5-9, 11-12 and 14-17>
An image-forming product was obtained in the same manner as in Test 1 except that the recording medium was changed to that shown in Table 2.

<Preparation of test 4>
An image-forming product was obtained in the same manner as in Test 1 except that the drying conditions after image formation were changed as shown in Table 2.

<Tests 10 and 13>
An image-forming product was obtained in the same manner as in Test 1 except that the recording medium and the drying conditions after image formation were changed as shown in Table 1.

<Test 18>
An image-forming product was obtained in the same manner as in Test 13 except that the type of ink was changed as shown in Table 2.

In Tests 1 to 18, the extraction amount of the water-soluble resin, the adhesion, the permissible bleeding printing speed and the laminating strength, and the ink ejection property of the image forming material were evaluated by the following methods.

(1) Extraction amount of water-soluble resin When the obtained image-forming product was immersed in water at 40 ° C. for 1 hour, the amount of water-soluble resin (PVA) eluted in the water was measured by GC-MS (gas chromatograph). -Measured by mass spectrometer). The amount of the water-soluble resin extracted from the film substrate measured for blank measurement described above was subtracted from the obtained value to obtain the total amount of the water-soluble resin extracted from the treatment layer and the image forming layer. The measurement conditions for GC-MS were the same as described above.

(2) Adhesion The cellophane tape was crimped onto the obtained image portion, and the state after the end of the tape was peeled off at a stretch at an angle of 45 ° was observed, and the adhesion was evaluated according to the following criteria.
◯: The solid image does not come off and is the same as before the test.
Δ: There is a slight color transfer on the tape side, but the solid image looks uniform.
×: A part of the solid image has been peeled off and is mottled.
Δ The above is a practically preferable range.

(3) Permissible bleeding print speed With respect to the obtained image, the permissible print speed at which 6-point characters can be clearly confirmed without bleeding was evaluated according to the following criteria.
⊚: Permissible bleeding print speed is 50 m / min or more ○: Permissible bleeding print speed is 20 m / min or more and less than 50 m / min Δ: Permissible bleeding print speed is 5 m / min or more and less than 20 m / min ×: Permissible bleeding print speed is 5 m / min Less than a minute Δ or more is a practically preferable range.

(4) Laminate strength (4-1) Preparation of film laminate A polyurethane adhesive (Takelac A-969V / Takenate A-5, manufactured by Mitsui Chemicals, Inc.) is applied on the image of the obtained image-forming product with a wet film thickness. After applying to a size of 3 μm, it was dried to form an adhesive layer. A nylon film (Emblem ONBC-25 manufactured by Unitika, thickness 25 μm) is laminated on this adhesive layer using a dry laminating machine, and then laminated (thermocompression bonded) to form an image / adhesive layer /. A film laminate having a laminated structure of nylon film was obtained.

(4-2) Measurement of Laminate Strength The obtained film laminate was cut into a width of 15 mm to obtain a test piece. The peel strength between the image of this test piece and the nylon film was measured using a T-type peeling tester. Then, it was evaluated according to the following criteria.
⊚: Peeling strength is 5N / 15mm or more ○: Peeling strength is 2N / 15mm or more and less than 5N / 15mm Δ: Peeling strength is 1N / 15mm or more and less than 2N / 15mm ×: Peeling strength is less than 1N / 15mm Δ or more is practically preferable The range.

(5) Using the same printer as the evaluation of the ink ejection property test 1, solid images of 35 × 35 mm each were recorded on the above-mentioned recording medium 1 at a transport speed of 50 m / min and one scan. After stopping the inkjet head for 20 seconds at a position 5 mm apart from the above image, a solid image was similarly recorded adjacently. Similarly, the head stop time was changed to 1 minute and 3 minutes, and two adjacent solid images were recorded at 5 mm intervals, respectively.
Using the square image formed as described above, the head stop time at which the edge of the image starts to be disturbed due to the abnormal ejection of ink was determined, and the ejection stability was evaluated based on the following criteria.
◯: No disturbance is observed at the edge of the image even after the head stop time of 3 minutes, and a good print image can be obtained. Δ: No disturbance is observed at the edge of the image after the head stop time of 1 minute, but after 3 minutes. Then, a slight turbulence is observed, which is a practically acceptable range. ×: A turbulence is observed at the edge of the image after the head stop time of 20 seconds, which is out of the practically acceptable range.
Δ The above is a practically preferable range.

Table 2 shows the test conditions and evaluation results of tests 1 to 18.

As shown in Table 2, it is a recording medium provided with a treatment layer containing a water-soluble resin and a curing agent, and the dry thickness of the treatment layer is 0.3 μm or more and 3 μm or less, and after immersion at 40 ° C. for 1 hour. In tests 1, 2, 4, 5, 8 and 11-18 using a recording medium in which the extraction amount of the water-soluble resin was 0.1 g / m ² or more and 2 g / m ^{2 or less, all of them had good bleeding tolerance prints.} It can be seen that the speed can be obtained, and good image adhesion and laminating strength can be obtained.

In particular, by setting the drying time to a certain level or longer in the ink drying step, the extraction amount of the water-soluble resin after image formation can be reduced to ^{less than 0.1 g / m 2} , and the adhesion and the laminating strength can be further improved. It can be seen (comparison between tests 1 and 4, comparison between tests 12 and 13).

Further, it can be seen that the permissible bleeding printing speed can be further increased by further containing the flocculant in the treated layer (comparison between Tests 1 and 11).

Further, it can be seen that the treated layer can further enhance the adhesion and the laminating strength by further containing the water-dispersible resin (comparison between tests 11 and 12).

On the other hand, the test 10 using the recording medium 9 in which the treated layer does not contain a curing agent, and the test 6 using the recording medium 5 in which ^{the extraction amount of the water-soluble resin after immersion at 40 ° C. for 1 hour exceeds 2 g / m 2.} In the test 7 using the recording medium 6 in which the dry thickness of the treated layer is thicker than 3 μm, it can be seen that the adhesion of the image and the laminating strength are low. It is considered that this is because the water-soluble resin in the treated layer is not sufficiently cured.

Further, the test 3 using the recording medium 3 in which the extraction amount of the water-soluble resin after immersion at 40 ° C. for 1 hour ^{is less than 0.1 g / m 2} and the recording medium 8 in which the dry thickness of the treated layer is thinner than 0.3 μm are used. In the test 9 used, it can be seen that the permissible bleeding print speed, the adhesion, and the laminating strength are all low. It is considered that this is because the water-soluble resin in the treated layer has been cured too much, so that the water-soluble resin in the treated layer is difficult to elute into the ink.

According to the present invention, it is possible to provide an inkjet image forming method capable of forming an image capable of suppressing ink bleeding, having good adhesion to a recording medium, and suppressing cracking under high humidity storage. can.

Claims (13)

It has a film substrate and a treatment layer disposed on the film substrate and containing a curing agent and a water-soluble resin having a functional group that reacts with the curing agent.
The film thickness of the treated layer is 0.3 μm or more and 3.0 μm or less.
The amount of the water-soluble resin extracted from the treatment layer when immersed in water at 40 ° C. for 1 hour is 0.1 g / m ² or more and 2.0 g / m ² or less.
Inkjet recording medium. The functional group that reacts with the curing agent is selected from the group consisting of a hydroxyl group, an amino group and a carboxyl group.
The inkjet recording medium according to claim 1. The curing agent is selected from the group consisting of an isocyanate-based curing agent, a carbodiimide-based curing agent, an oxazoline-based curing agent, and an epoxy-based curing agent.
The inkjet recording medium according to claim 1 or 2. The treated layer further contains a compound that aggregates the coloring material.
The inkjet recording medium according to any one of claims 1 to 3. The treated layer further contains a water-dispersible resin.
The inkjet recording medium according to any one of claims 1 to 4. The recording medium preparation step for preparing the inkjet recording medium according to any one of claims 1 to 5.
An ink application step of applying an ink containing at least a coloring material and water onto the inkjet recording medium by an inkjet method.
It has an ink drying step of forming an image forming layer by drying the applied ink at a temperature of 40 ° C. or higher.
Image formation method. In the ink drying step, when the obtained image-forming product is immersed in water at 40 ° C. for 1 hour, the total amount of the treated layer and the water-soluble resin extracted from the image-forming layer is less than ^{0.1 g / m 2.} Do it to be
The image forming method according to claim 6. The ink drying step is
The step of drying the ink at the second drying temperature and
It comprises a step of further heating the ink at a second heating temperature lower than the second drying temperature.
The image forming method according to claim 7. The recording medium preparation step is
A treatment liquid application step of applying a treatment liquid containing at least a curing agent, a water-soluble resin having a functional group that reacts with the curing agent, and water to a film substrate.
It has a treatment liquid drying step of forming a treatment layer by drying the treatment liquid applied to the film substrate at a temperature of 40 ° C. or higher.
The image forming method according to any one of claims 6 to 8. The treatment liquid drying step is
The step of drying the treatment liquid at the first drying temperature and
It comprises a step of further heating the treatment liquid at a first heating temperature lower than the first drying temperature.
The image forming method according to claim 9. The ink is substantially free of water-dispersible resin.
The image forming method according to any one of claims 6 to 10. The coloring material is titanium oxide.
The image forming method according to any one of claims 6 to 11. An image forming step of forming an image forming layer on an inkjet recording medium by the image forming method according to any one of claims 6 to 12.
It has a film laminating step of laminating a film on the image forming layer via an adhesive layer.
A method for manufacturing a film laminate.