JP2006281568A - Print base solution for plastic film and ink jet recording method using the same - Google Patents

Abstract

【選択図】 なしPROBLEM TO BE SOLVED: To provide a printing base solution which can be used together with an aqueous pigment ink composition to form a plastic recorded matter excellent in abrasion resistance, scratch resistance and water resistance.
A printing base solution according to the present invention is for an ink jet recording medium having a recording surface of a plastic film, and is represented by the formula (I) [wherein R is a linear or branched C2- 12 represents a saturated hydrocarbon chain, and X represents —CH ₂ — or —O—], a thermoplastic ester resin, and a main solvent. Is dispersed in the base solution.
[Chemical 1]

[Selection figure] None

Description

Background of the Invention

The present invention relates to a printing base solution for plastic films. Specifically, the present invention is used when printing on a recording medium whose recording surface is a plastic film, and is applied prior to printing of the water-based ink composition on the recording surface. The present invention relates to a printing base solution capable of forming The present invention also relates to an ink jet recording method using such a base solution.

BACKGROUND ART An ink jet recording method is a printing method in which printing is performed by causing droplets of an ink composition to fly and adhere to a recording surface of a recording medium. This method has a feature that a high-resolution and high-quality image can be printed at a high speed with a relatively inexpensive apparatus. As a recording medium, there is an increasing demand for materials such as plastic film in addition to general paper.

  The plastic recorded matter obtained by printing on a plastic film or the like is assumed to be used for posting outdoors where paper cannot be used. For this reason, a higher degree of water resistance and light resistance is required for the plastic recorded matter. In addition, printing of an object touched by a hand such as a label is more suitable for a plastic recorded material than for a paper printed material. Also in this case, the recorded material is required to have durability such as abrasion resistance.

  Conventionally, solvent-based ink, UV curable ink, or two-component curable ink has been used for inkjet recording using a plastic film such as vinyl chloride that has not been surface-treated exclusively for inkjet printing. It was. However, the solvent-based ink has a solvent odor and may contain harmful components in the solvent volatile components. Even in a UV curable ink or a two-component curable ink, the curable monomer to be used may contain harmful components.

  Further, when ink-jet recording is performed on a plastic film not subjected to surface treatment exclusively for ink-jet recording using a conventional water-based ink, the adhesion, scratch resistance and water resistance of the recorded image cannot be said to be sufficient.

  In the case of using a plastic film exclusively for ink jet recording, a method of coagulating and curing a colorant or a dispersion resin as an ink component using water-based ink (Japanese Patent Laid-Open No. 9-286940 (Patent Document 1)) is proposed. ing.

  Further, for example, Japanese Unexamined Patent Application Publication No. 2003-11486 (Patent Document 2) discloses an ink jet recording method using a pretreatment liquid. However, this recording method is intended to perform recording with high image quality and water resistance on a general recording medium, and is not intended for printing on a plastic film.

  For this reason, an ink jet recording method using an aqueous pigment ink capable of obtaining a plastic recorded matter excellent in water resistance and abrasion resistance is desired.

JP-A-9-286940 JP 2003-11486 A

Summary of the Invention

  In the present invention, prior to attaching the ink composition to the surface of the plastic film, a ground solution having a specific composition containing a specific cyclic ester compound is previously applied to treat the surface of the plastic film. It has been found that by forming a base film there, the abrasion resistance, scratch resistance, and water resistance of the plastic recording material formed by adhering the ink composition can be greatly improved. The present invention is based on such knowledge.

  Therefore, the present invention can form a plastic film excellent in abrasion resistance, scratch resistance, and water resistance by forming a base film having high adhesion with the ink composition to be adhered, and printing for plastic film. The purpose is to provide a base solution. Another object of the present invention is to provide an ink jet recording method using such a base solution.

［式中、
Ｒは、直鎖状もしくは分岐鎖状の、Ｃ２〜１２の飽和炭化水素鎖を表し、かつ
Ｘは、−ＣＨ_２−または−Ｏ−を表す］。 A printing ground solution for an inkjet recording medium having a recording surface of a plastic film according to the present invention comprises at least a cyclic ester compound of the following formula (I), a thermoplastic resin, and a main solvent, A plastic resin is dispersed in a base solution:

[Where:
R represents a linear or branched C2-12 saturated hydrocarbon chain, and X represents —CH ₂ — or —O—.

According to a preferred embodiment of the present invention, the main solvent of the base solution is water.
According to a preferred embodiment of the present invention, the base solution further comprises a surfactant and / or a low surface tension organic solvent.

  The ink jet recording set according to the present invention comprises an aqueous pigment ink composition comprising at least the ground solution according to the present invention, a pigment, a thermoplastic resin, and water.

  In the ink jet recording method according to the present invention, a base liquid is formed on a recording medium whose recording surface is a plastic film to form a base film, and then droplets of the ink composition are ejected to adhere to the base film. An ink jet recording method for performing printing, wherein the base liquid is the printing base liquid according to the present invention, and the ink composition comprises at least a pigment, a thermoplastic resin, and water. It is.

Detailed description of the invention

As described above, the printing base solution according to the present invention is used for printing on an ink jet recording medium having a recording surface made of a plastic film, and includes a cyclic ester compound of the formula (I) and a thermoplastic resin. A resin and at least a main solvent are contained, and a thermoplastic resin is dispersed in a base solution. In other words, the base solution according to the present invention comprises a dispersion medium comprising at least the cyclic ester compound of formula (I) and a main solvent, and a thermoplastic resin dispersed in the dispersion medium. Here, the main solvent is preferably water as described later. The base solution according to the present invention preferably further comprises a surfactant and / or a low surface tension organic solvent, more preferably further comprises a surfactant, or the surfactant and the low surface tension. It further comprises a tension organic solvent. In addition, the base solution according to the present invention can further contain a wetting agent described later. Furthermore, the base solution according to the present invention is preferably applied to a recording medium by an ink jet recording method.

  The base solution according to the present invention is used for printing on a recording medium whose recording surface is a plastic film. Here, the recording medium whose recording surface is a plastic film includes, in addition to the recording medium itself being a plastic film, a plastic recording material on a conventional recording medium substrate such as paper, Also included are those obtained by bonding a plastic film thereon. Here, the plastic is not particularly limited as long as it can be dissolved or wetted by the cyclic ester compound of formula (I). For example, vinyl chloride, polyethylene terephthalate (PET), polycarbonate, Examples thereof include polystyrene and polyurethane. In the present invention, the plastic is preferably vinyl chloride. Further, the base solution according to the present invention can be used for printing on any of a plastic film that has not been subjected to a surface treatment dedicated to inkjet printing and a plastic film that has been subjected to a surface treatment dedicated to inkjet printing.

  The base liquid of the present invention is preferably used together with an ink composition comprising a thermoplastic resin, so that the surface of the plastic film and the resin film formed by drying the ink are formed by the base liquid. It can adhere firmly through the base film. As a result, it is possible to form a plastic recorded matter excellent in abrasion resistance, scratch resistance, and water resistance. In this case, the ink composition preferably includes at least a pigment, a thermoplastic resin, and water. Thus, according to the present invention, since a pigment-based aqueous ink composition can be used, a recorded matter having excellent light resistance can be formed on a plastic film.

  Here, the base film means a state in which all or a part of the water in the base liquid evaporates, so that the thermoplastic resin contained in the base liquid is cured, and the entire base liquid becomes an integral film.

The reason why the desired effect is achieved by the present invention is considered as follows. However, the following is assumed and the present invention is not limitedly interpreted by this.
When the base solution according to the present invention is applied to a plastic film, it spreads uniformly on the surface, and when water is evaporated in this state, the cyclic ester compound can remain on the plastic film surface uniformly and at a high concentration. As a result, the cyclic ester compound can dissolve or wet a portion that is extremely shallow from the surface of the plastic film. At the same time, the resin component contained in the base solution is cured to form a film, and a base film is formed. At this time, it is considered that the base film forms a mixed layer with the dissolved plastic. For this reason, the base film which the plastic film surface and the resin film were integrated and adhered firmly to the plastic film surface is obtained. When an ink composition containing a resin that can be formed into a film by heating is further adhered thereto, and then the resin contained therein is cured to form a film, the cured film of the ink is strongly bonded to the base film. At this time, if the resin contained in the base liquid and the ink composition are the same component, the bond is further strengthened. By using the base solution, it is considered that the adhesion between the ink layer and the plastic film can be dramatically improved through the base film. As a result of this increased adhesion, there is almost no peeling of the print due to external forces such as rubbing or water permeation into the interface, and a plastic recorded matter excellent in abrasion resistance, scratch resistance, and water resistance can be formed. Can do. For this reason, it becomes possible to produce a tough printed matter that takes advantage of the durability of the plastic film itself.

  In the base solution according to the present invention, since the cyclic ester compound, which is a component capable of dissolving the plastic, is preferably diluted with water, the liquid contact member constituting the printer is hardly destroyed or damaged. Further, since the preferred base solution according to the present invention is an aqueous solution, the base solution itself and generated steam are also excellent in safety.

Cyclic ester compound The ground solution according to the present invention comprises the cyclic ester compound of formula (I) as an essential component.
In formula (I), as described above, R represents a linear or branched C2-12 saturated hydrocarbon chain, and X represents —CH ₂ — or —O—. R preferably represents a C2-8 saturated hydrocarbon chain, more preferably a C2-5, more preferably a C2-4 saturated hydrocarbon chain. Here, for example, “C2-12” in the case of “C2-12 saturated hydrocarbon chain” means that the saturated hydrocarbon chain has 2 to 12 carbon atoms.

Also the saturated hydrocarbon chain linear C2~12, - _(CH 2) (in m here represents an integer of 2 to 12) chain represented by m- means that the. The branched saturated hydrocarbon chain C2~12, - (CH 2) a chain represented by _n-, the hydrogen on the carbon in the carbon number total such that p number 1 or more It means a chain having a side chain substituted with an alkyl group (where n + p (p is the total number of carbons in all side chains) represents an integer of 2 to 12). Examples of such an alkyl substituent include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, an isobutyl group, an s-butyl group, and a t-butyl group. Moreover, the saturated hydrocarbon chain on a straight chain or branched chain may be further substituted with a hydroxyl group, hydroxymethylene, or the like, if necessary.
Specific examples of the linear or branched C2-12 saturated hydrocarbon chain include ethylene and propylene.

  Specific examples of the cyclic ester compound include γ-butyrolactone, ε-caprolactone, δ-hexanolactone, propylene carbonate, ethylene carbonate, 1,3-dioxane-2-one, and preferably γ-butyrolactone, Examples thereof include those selected from the group consisting of ε-caprolactone, propylene carbonate, and ethylene carbonate. More preferably, the cyclic ester compound is γ-butyrolactone or propylene carbonate.

  In the base solution of the present invention, one or more cyclic ester compounds may be mixed and used. Although the cyclic ester compound used in this invention may be synthesize | combined as needed, you may use a commercial item.

  If the content of the cyclic ester compound is too small relative to the entire base solution composition, the plastic surface may not be sufficiently dissolved, and the base film and the plastic may not adhere to each other. Moreover, when there is too much content of a cyclic ester compound, the dispersion stability of a resin component may deteriorate. Therefore, the content of the cyclic ester compound in the undercoat liquid of the present invention can be uniformly applied to the recording medium in consideration of the above points, can be set to a predetermined surface tension, and constitutes a printer. It is desirable that the selection be made so that the liquid contact member is hardly destroyed or damaged. The content of the cyclic ester compound is, for example, 0.1 to 40.0% by weight, preferably 2.0 to 25.0% by weight, based on the total amount of the base solution.

Thermoplastic resin The base solution of the present invention comprises a thermoplastic resin. As the thermoplastic resin, a resin that is soluble in the main solvent of the base solution or an insoluble resin can be used. As the resin soluble in the main solvent of the base solution, a resin dispersant used for dispersing a pigment described later can be suitably used. Moreover, it is preferable that the resin insoluble in the main solvent of the base solution is added to the base solution in the form of a resin emulsion. Here, the resin emulsion is composed of a main solvent as a continuous phase and a resin component (thermoplastic resin component) as a dispersed phase.

  According to a preferred embodiment of the present invention, the thermoplastic resin is preferably a polymer having both a hydrophilic portion and a hydrophobic portion. When a resin emulsion is used as the thermoplastic resin, the particle size is not particularly limited as long as the emulsion is formed, but is preferably about 150 nm or less, more preferably about 5 to 100 nm.

  As the thermoplastic resin, a resin component similar to a dispersant resin or a resin emulsion conventionally used in ink compositions for ink jet recording can be used. Specific examples of the thermoplastic resin include acrylic polymers such as polyacrylic acid esters or copolymers thereof, polymethacrylic acid esters or copolymers thereof, polyacrylonitrile or copolymers thereof, polycyanoacrylates, poly Acrylamide, polyacrylic acid, or polymethacrylic acid; polyolefin polymers such as polyethylene, polypropylene, polybutene, polyisobutylene, polystyrene or copolymers thereof, petroleum resins, coumarone-indene resins, or terpene resins; vinyl acetate Vinyl alcohol polymers such as polyvinyl acetate or copolymers thereof, polyvinyl alcohol, polyvinyl acetal, or polyvinyl ether; halogen-containing polymers such as polyvinyl chloride or copolymers thereof. Polymers, polyvinylidene chloride, fluororesins, or fluororubbers; nitrogen-containing vinyl polymers such as polyvinyl carbazole, polyvinyl pyrrolidone or copolymers thereof, polyvinyl pyridine, or polyvinyl imidazole; diene polymers such as polybutadiene or the like A copolymer, polychloroprene, or polyisoprene (butyl rubber); or other ring-opening polymerization resin, condensation polymerization resin, natural polymer resin, or the like can be used.

  When the thermoplastic resin is obtained in the form of an emulsion, it can be prepared by mixing the resin particles with water, optionally with a surfactant. For example, an emulsion of an acrylic resin or a styrene-acrylic acid copolymer resin is composed of a (meth) acrylic ester resin or a styrene- (meth) acrylic ester resin, and optionally a (meth) acrylic resin, It can be obtained by mixing the active agent with water. The mixing ratio of the resin component and the surfactant is usually preferably about 50: 1 to 5: 1. When the amount of the surfactant used is less than the above range, it is difficult to form an emulsion, and when it exceeds the above range, the water resistance of the base film and ink is lowered or the adhesion is deteriorated. Since there is a tendency, it is not preferable.

  The surfactant used in the preparation of the resin emulsion is not particularly limited, but preferred examples include anionic surfactants (for example, sodium dodecylbenzansulfonate, sodium laurylate, ammonium salt of polyoxyethylene alkyl ether sulfate, etc.) ), Nonionic surfactants (eg, polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene alkylphenyl ether, polyoxyethylene alkylamine, polyoxyethylene alkylamide, etc.) These may be used, and two or more of these may be used in combination.

  An emulsion of a thermoplastic resin can also be obtained by emulsion polymerization of the above resin component monomers in water in the presence of a polymerization catalyst and an emulsifier. A polymerization initiator, an emulsifier, and a molecular weight modifier used in the emulsion polymerization can be used according to a conventional method.

  As the polymerization initiator, the same ones used for normal radical polymerization can be used, for example, potassium persulfate, ammonium persulfate, hydrogen peroxide, azobisisobutyronitrile, benzoyl peroxide, peroxide. Examples include dibutyl, peracetic acid, cumene hydroperoxide, t-butyl hydroxy peroxide, paramentane hydroxy peroxide, and the like. When the polymerization reaction is performed in water, a water-soluble polymerization initiator is preferable. Examples of the emulsifier include sodium lauryl sulfate, those generally used as an anionic surfactant, nonionic surfactant or amphoteric surfactant, and mixtures thereof. These can be used in combination of two or more.

  The ratio of the resin and water as the dispersed phase component is preferably 60 to 400 parts by weight, more preferably 100 to 200 parts by weight of water with respect to 100 parts by weight of the resin.

  When a resin emulsion is used as the thermoplastic resin, a known resin emulsion can be used. For example, the resin emulsions described in JP-B-62-1426, JP-A-3-56573, JP-A-3-79678, JP-A-3-160068, or JP-A-4-18462 can be used as they are. . Commercially available resin emulsions can also be used. For example, Microgel E-1002, E-5002 (styrene-acrylic resin emulsion; manufactured by Nippon Paint Co., Ltd.), Boncoat 4001 (acrylic resin emulsion; Dainippon) Ink Chemical Co., Ltd.), Boncoat 5454 (styrene-acrylic resin emulsion; Dainippon Ink and Chemicals Co., Ltd.), SAE1014 (styrene-acrylic resin emulsion; manufactured by Nippon Zeon Co., Ltd.), or Cybinol SK-200 ( Acrylic resin emulsion; manufactured by Seiden Chemical Co., Ltd.).

  In the present invention, the thermoplastic resin may be mixed with other components in the base solution as fine particle powder. However, after the resin fine particles are dispersed in an aqueous medium to form a resin emulsion, It is preferred to mix with the ingredients.

  From the viewpoint of long-term storage stability and ejection stability of the base solution, the resin fine particles preferably used in the present invention have a particle size in the range of 5 to 400 nm, more preferably in the range of 50 to 200 nm.

  The thermoplastic resin is preferably contained in the range of 0.1 to 15.0% by weight in terms of solid content, and preferably in the range of 1.0 to 10.0% by weight, based on the total amount of the base solution. More preferred. If the resin component is too small in the base solution, the base film formed on the plastic surface may become thin and adhesion to the ink layer may be insufficient. If the resin component is too much, the dispersion of the resin may become unstable during storage of the base solution, or the resin component may be agglomerated and solidified due to the slight evaporation of water, making it impossible to form a uniform base film.

  According to a preferred aspect of the present invention, the thermoplastic resin as the base liquid component is the same component as the thermoplastic resin used in the ink composition described below. By using the same component, the affinity between the base film and the resin film formed from the ink composition is increased, and the mutual adhesion can be further strengthened.

A surfactant aqueous solution is usually repelled by plastics, but a surfactant and / or a low surface tension organic solvent can be added to the base solution according to the present invention, so that a cyclic ester compound is uniformly coated on the plastic surface. be able to. By evaporating water from the uniformly applied base solution, the cyclic ester compound can be fixed on the plastic surface without excess and deficiency, and only the plastic surface in a desired region can be dissolved. In addition, since the base solution is uniformly applied, the resin contained in the base solution can be uniformly formed on the surface of the plastic film.

  In the present invention, as the surfactant, any of anionic, cationic, amphoteric, and / or nonionic can be used.

  Examples of the anionic surfactant include alkyl sulfocarboxylates, α-olefin sulfonates, polyoxyethylene alkyl ether acetates, N-acyl amino acids and salts thereof, N-acyl methyl taurates, alkyl sulfates. Polyoxyalkyl ether sulfate, alkyl sulfate polyoxyethylene alkyl ether phosphate, rosin acid soap, castor oil sulfate ester, lauryl alcohol sulfate ester, alkylphenol type phosphate ester, alkyl type phosphate ester, alkylaryl sulfonate, Examples thereof include diethyl sulfosuccinate, diethylhexyl sulfosuccinate, dioctyl sulfosuccinate, 2-vinylpyridine derivatives, poly-4-vinylpyridine derivatives, and the like.

  Examples of amphoteric surfactants include lauryldimethylaminoacetic acid betaine, 2-alkyl-N-carboxymethyl-N-hydroxyethylimidazolinium betaine, coconut oil fatty acid amidopropyldimethylaminoacetic acid betaine, polyoctylpolyaminoethylglycine and other imidazolines. Derivatives and the like can be mentioned.

（ここで、Ｒ^１１、Ｒ^１２、Ｒ^１３、およびＲ^１４はそれぞれ独立して炭素数１〜６のアルキル基を表し、ｎおよびｍはそれらの和が０〜３０となる整数である）で表されるアセチレングリコール系界面活性剤、例えば、２，４，７，９−テトラメチル−５−デシン−４，７−ジオール（例えば、Air Products and Chemicals. Inc.社製のサーフィノール１０４）、３，６−ジメチル−４−オクチン−３，６−ジオール（例えば、Air Products and Chemicals. Inc.社製のサーフィノール８２）、これらアセチレングリコール類の誘導体（例えば、Air Products and Chemicals. Inc.社製のサーフィノール４６５、４８５など）などがある。 Examples of the nonionic surfactant include polyoxyethylene nonyl phenyl ether, polyoxyethylene dodecyl phenyl ether, polyoxyethylene alkyl aryl ether, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether, Ethers such as polyoxyalkylene alkyl ether, polyoxyethylene oleate, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan laurate, sorbitan monostearate, sorbitan monooleate, sorbitan sesquioleate, poly Esters such as oxyethylene monooleate and polyoxyethylene stearate, or the following formula (i):

(Wherein R ¹¹ , R ¹² , R ¹³ , and R ¹⁴ each independently represents an alkyl group having 1 to 6 carbon atoms, and n and m are integers whose sum is 0 to 30). Acetylene glycol surfactants such as 2,4,7,9-tetramethyl-5-decyne-4,7-diol (eg, Surfynol 104 from Air Products and Chemicals. Inc.), 3,6-dimethyl-4-octyne-3,6-diol (for example, Surfynol 82 manufactured by Air Products and Chemicals. Inc.) and derivatives of these acetylene glycols (for example, Air Products and Chemicals. Inc.) Manufactured by Surfinol 465, 485, etc.).

  Among these, nonionic surfactants having good foaming or nozzle ejection reliability are preferable, and acetylene glycol surfactants are more preferable.

The content of the surfactant in the base solution of the present invention is not particularly limited as long as it can uniformly coat the cyclic ester compound on the plastic surface, and the type of surfactant used and the type of cyclic ester compound And it can select suitably according to the quantity. The content of the surfactant is, for example, 0.01 to 5.0% by weight, preferably 0.1 to 2.0% by weight, based on the total amount of the base solution.
Low surface tension organic solvent In order to uniformly coat the cyclic ester compound on the plastic surface, the base solution of the present invention comprises a low surface tension organic solvent instead of or in addition to the surfactant. be able to.

  Examples of the low surface tension organic solvent include monohydric alcohols and polyhydric alcohol derivatives.

  As the monohydric alcohol, a monohydric alcohol having 1 to 4 carbon atoms such as methanol, ethanol, n-propanol, i-propanol, or n-butanol can be used.

In particular, as the polyhydric alcohol derivative, a complete or partial ether of a divalent to pentavalent alcohol having 2 to 6 carbon atoms and a lower alcohol having 1 to 4 carbon atoms can be used. Here, the polyhydric alcohol derivative is an alcohol derivative in which at least one hydroxyl group is etherified, and does not mean a polyhydric alcohol itself that does not contain an etherified hydroxyl group. The preferred polyhydric alcohol lower alkyl ether as the ether is represented by the general formula (ii):
R ²¹ _O-[CH 2 -CH ^(R 23) -O] ^{t-R 22} (ii)
[Wherein R ²¹ and R ²² each independently represent a hydrogen atom or an alkyl group having 3 to 6 carbon atoms (preferably a butyl group), and R ²³ represents a hydrogen atom or a lower alkyl having 1 to 4 carbon atoms. A group, preferably a hydrogen atom, a methyl group or an ethyl group, and t is an integer of 1 to 8, preferably 1 to 4, provided that at least one of R ²¹ and R ²² is an alkyl having 3 to 6 carbon atoms. It is a group (preferably a butyl group)].

  Specific examples of these polyhydric alcohol lower alkyl ethers include, for example, mono, di or triethylene glycol-mono or di-alkyl ether, mono, di or tripropylene glycol-mono or di-alkyl ether, and preferably May include triethylene glycol monobutyl ether, diethylene glycol monobutyl ether, diethylene glycol monopropyl ether, diethylene glycol monopentyl ether, or propylene glycol monobutyl ether.

  According to a preferred embodiment of the present invention, the low surface tension organic solvent is diethylene glycol monobutyl ether or triethylene glycol monobutyl ether.

  The content of the low surface tension organic solvent in the base solution of the present invention is not particularly limited as long as the cyclic ester compound can be uniformly applied to the plastic surface, and the type of cyclic ester compound and surfactant to be used. And can be selected according to the amount. The content of the low surface tension organic solvent is, for example, 0 to 25.0% by weight, preferably 2.0 to 15.0% by weight, based on the total amount of the base solution.

  Although various physical properties of the base solution according to the present invention can be appropriately controlled, according to a preferred embodiment of the present invention, the viscosity of the base solution is preferably 25 mPa · sec or less, more preferably 10 mPa · sec or less (25 ° C.). It is. When the viscosity is within this range, the base liquid can be stably discharged from the ink discharge head. The undercoat liquid according to the present invention can be appropriately controlled, and the surface tension is preferably in the range of 20.0 to 40.0 mN / m (25 ° C.), more preferably 25.0 to 35.0 mN / m. m range.

In consideration of storage of the wetting agent base solution and handling at the time of application, a known wetting agent (water-soluble organic solvent) can be further added to the base solution according to the present invention. By including the wetting agent, it is possible to prevent aggregation and solidification of the resin component due to water evaporation, prevent clogging of the nozzles of the ink jet head during ink jet application, and ensure ejection stability.

  Examples of the wetting agent include water-soluble polyhydric alcohols, in particular, divalent to pentavalent alcohols having 2 to 10 carbon atoms; nitrogen-containing hydrocarbon solvents such as formamides, imidazolidinones, pyrrolidones, Or amines; a sulfur-containing hydrocarbon solvent can be mentioned. You may use these in combination of 2 or more types.

  Examples of the water-soluble polyhydric alcohol include divalent to trivalent alcohols having 3 to 10 carbon atoms such as glycerin, ethylene glycol, diethylene glycol, triethylene glycol, dipropylene glycol, hexylene glycol, 1,2,6- One or more hexanetriols can be used in combination.

  The content of the wetting agent is, for example, 0 to 5.0% by weight, preferably 1.0 to 5.0% by weight with respect to the total amount of the base solution. By setting it as such a range, clogging prevention property or discharge stability can be ensured. When there is too much content, it may become a dry defect.

Main solvent The base solution according to the present invention comprises a main solvent. In order to apply the water-soluble component containing the cyclic ester compound thinly and uniformly to the plastic surface, in the present invention, the cyclic ester compound is applied after being diluted with a main solvent. As such a main solvent, water or a water-soluble organic solvent can be used. In the present invention, water is preferable from the viewpoint of safety and the like.
Therefore, in the base solution in the present invention, preferably, the main solvent is water. As water used here, pure water such as ion exchange water, ultrafiltration water, reverse osmosis water, distilled water, or ultrapure water is used for the purpose of reducing ionic impurities as much as possible. it can. In addition, it is preferable to use water sterilized by ultraviolet irradiation or addition of hydrogen peroxide because generation of mold and bacteria can be prevented when the base solution is stored for a long period of time.

Other components The base solution of the present invention can achieve a desired effect by including the above-described components, but if necessary, an antiseptic / antifungal agent, a pH adjuster, a dissolution aid, An antioxidant, a nozzle clogging preventing agent, and the like can be further included.

  Examples of the pH adjuster include potassium dihydrogen phosphate and disodium hydrogen phosphate. Examples of preservatives and fungicides include sodium benzoate, sodium pentachlorophenol, sodium 2-pyridinethiol-1-oxide, sodium sorbate, sodium dehydroacetate, 1,2-dibenzisothiazoline-3-one (Proxel CRL, Proxel BDN, Proxel GXL, Proxel XL-2, Proxel TN from ICI) and the like. Furthermore, examples of the dissolution aid or antioxidant include amines such as diethanolamine, triethanolamine, propanolamine, morpholine and their modified products, inorganic salts such as potassium hydroxide, sodium hydroxide, and lithium hydroxide. , Ammonium hydroxide, quaternary ammonium hydroxide (such as tetramethylammonium), carbonates such as potassium carbonate, sodium carbonate, lithium carbonate, and other phosphates, or N-methyl-2-pyrrolidone, urea, thiourea, tetra Examples include L-ascorbic acid and salts thereof, such as ureas such as methylurea, allophanates such as allophanate and methylallohanate, and biurets such as biuret, dimethylbiuret and tetramethylbiuret. Furthermore, urea, thiourea, ethylene urea or the like can be added for the purpose of preventing nozzle drying.

Manufacture of base solution The base solution of the present invention is prepared by appropriately mixing and dissolving (or dispersing) each of the above-mentioned blending components in an arbitrary order, and then filtering and removing impurities as necessary. can do.

In the base solution according to the present invention, the cyclic ester compound can be uniformly applied to the plastic surface; the viscosity and the surface tension can be discharged by the ink jet recording head; the base solution aggregates in the storage container or at the nozzle of the ink jet head. In addition, the amount of each component described above can be appropriately set in consideration of the fact that the liquid contact member of the ink jet printer is not dissolved or broken. Typical compositions of such a base solution include, for example, the following:
Cyclic ester compound 0.1 to 40.0% by weight;
Thermoplastic resin 0.1 to 15.0 wt% (solid content);
Surfactant 0.01-5.0% by weight;
Low surface tension organic solvent 0-25.0 wt%;
Wetting agent 0-5.0% by weight; and water remaining.

  Therefore, according to one preferable aspect of the present invention, in the base solution, the content of the cyclic ester compound is 0.1 to 40.0% by weight, and the content of the thermoplastic resin is 0.1 in terms of solid content. The content of the surfactant is 0.01 to 5.0% by weight.

Recording Method The inkjet recording method according to the present invention, as described above, discharges ink composition droplets after forming a base film by applying a printing base liquid to a recording medium whose recording surface is a plastic film. Printing on the recording surface.

  In the step of applying the base solution, the base solution according to the present invention is applied to the recording surface of the recording medium. In this step, it is desirable to apply a base solution in advance to at least a portion (printing portion) where ink is applied in the next step in which ink jet recording is performed. The coating amount can be appropriately adjusted according to the state of the plastic film that is the recording medium, the type of material, the amount of ink to be applied, and the like.

  In the present invention, the coating method of the base solution is not particularly limited, and for example, brush coating, air knife coater, roll coater, bar coater, blade coater, slide hopper coater, gravure coater, flexographic gravure coater, curtain coater, ext A coating method using a known coating device such as a rouge coater, a floating knife coater, a comma coater, a die coater, a gate roll coater, or a size press device, or non-spraying using a spray, an inkjet head, a jet nozzle, etc. The method of apply | coating by a contact system etc. are mentioned.

  In the present invention, the base liquid coating method is preferably an ink jet recording method in which droplets are ejected and adhered to a recording surface of a recording medium. By adopting the ink jet recording method, it is possible to appropriately control the application position and application amount of the base solution. By controlling the application position, the substrate solution can be applied only to the printing area, so the amount of substrate solution used can be saved, and the substrate solution can protrude from the plastic recording medium when printing the edges of the plastic recording medium. Can be prevented. In addition, when a large amount of solvent is applied to a plastic recording medium, the entire plastic is dissolved or softened. However, by controlling the coating amount, only a very shallow portion from the surface of the plastic recording medium can be selectively dissolved. it can.

  According to a preferred aspect of the present invention, the ink jet recording method according to the present invention further includes a drying step of evaporating the water of the applied base solution to form a base film before the ink composition is attached. After application to the recording medium, it is desirable that the water in the base solution is evaporated almost or completely. By this drying operation, the cyclic ester compound contained in the base solution can also be evaporated, so that it is considered that the adhesion between the plastic recording medium and the base film to be formed can be further strengthened.

  Drying of the water after applying the base solution can be performed according to a conventional method using a known heating device such as a conventional heating and drying means, for example, an infrared heating device or a hot air heating device. In the present invention, the drying process in the drying step can be preferably performed by heating with a heater or drying with hot air. The drying conditions can be appropriately changed according to the composition of the base solution used, the coating amount, and the like. For example, in the case of heater heating or hot air drying, drying can be performed at 25 to 90 ° C. (preferably 40 to 70 ° C.) for 1 minute to 1 day.

  Next, in the ink jet recording method of the present invention, after applying the base solution, the ink composition is adhered to the application surface. At this time, it is desirable that the method of attaching the ink is an ink jet recording method. Here, the ink composition contains at least a pigment, a thermoplastic resin, and water, which will be described later.

  According to a preferred aspect of the present invention, the ink jet recording method of the present invention further comprises a heating step of heating the ink composition adhered to the recording surface to form a resin film. Here, the heating means can be performed according to a conventional method using a conventional heating means, for example, a known heating device such as an infrared heating device or a hot air heating device. In the present invention, the heat treatment in the heating step can be preferably carried out by heater heating or hot air drying. Further, the heating condition may be any condition as long as the resin contained in the ink composition can be cured by heating to form a resin film, taking into account the type of resin particles and the like. It can be set appropriately. For example, in the case of heater heating or warm air drying, heating can be performed at 25 to 90 ° C. (preferably 40 to 70 ° C.) for 1 minute to 1 day (preferably 2 minutes to 16 hours). .

Aqueous Pigment Ink Composition The ink composition that can be used in the present invention is preferably an aqueous pigment ink composition comprising at least a pigment, a thermoplastic resin, and water.

Pigment:
In the present invention, the aqueous pigment ink composition may contain any pigment conventionally used in water-based inkjet recording ink compositions. As the pigment, for example, an organic pigment or an inorganic pigment conventionally used in an ink composition for inkjet recording can be used. The pigment is a resin-dispersed pigment dispersed with a dispersant such as a water-soluble resin or a surfactant, or a surface-treated pigment that has a hydrophilic group introduced into the pigment surface and can be dispersed or dissolved in an aqueous medium without the use of a dispersant. Can be added to the ink composition. In addition, when dispersing a pigment with a resin dispersing agent, you may use a thermoplastic resin as a dispersing agent. Two or more pigments may be used in combination.

  As the inorganic pigment, titanium oxide and iron oxide, or carbon black produced by a known method such as a contact method, a furnace method, or a thermal method can be used.

  Examples of organic pigments include azo pigments (for example, azo lakes, insoluble azo pigments, condensed azo pigments, or chelate azo pigments), polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, verinone pigments, anthraquinone pigments, quinacridone pigments, dioxazine pigments, A thioindigo pigment, an isoindolinone pigment, or a quinophthalone pigment), a dye chelate (for example, a basic dye chelate or an acid dye chelate), a nitro pigment, a nitroso pigment, or aniline black can be used. Of these pigments, it is preferable to use a pigment having good affinity with water.

  More specifically, as a pigment for black ink, for example, carbon black (CI pigment black 7) such as furnace black, lamp black, acetylene black, or channel black, or copper oxide, iron oxide ( And CI pigment black 11), metals such as titanium oxide, and organic pigments such as aniline black (CI pigment black 1).

  Specific examples of suitable carbon black include carbon black manufactured by Mitsubishi Chemical Corporation, No. 2300, 900, MCF88, no. 20B, no. 33, no. 40, no. 45, no. 52, MA7, MA8, MA100, No2200B and the like. Examples of carbon blacks manufactured by Degussa include color blacks FW1, FW2, FW2V, FW18, FW200, S150, S160, S170, Pretex 35, U, V, 140U, Special Black 6, 5, 4A, 4, 250, etc. It is done. Examples of carbon black manufactured by Columbia Carbon include Conductex SC, Raven 1255, 5750, 5250, 5000, 3500, 1255, 700, and the like. Examples of the carbon black manufactured by Cabot include Regal 400R, 330R, 660R, Mogul L, Monarch 700, 800, 880, 900, 1000, 1100, 1300, 1400, Elftex 12 and the like manufactured by Cabot.

  Examples of color ink pigments include C.I. I. Pigment Yellow 1 (Fast Yellow G), 3, 12 (Disazo Yellow AAA), 13, 14, 17, 23, 24, 34, 35, 37, 42 (Yellow Iron Oxide), 53, 55, 74, 81, 83 (Disazo Yellow HR), 95, 97, 98, 100, 101, 104, 108, 109, 110, 117, 120, 138, 153, 154; I. Pigment Red 1, 2, 3, 5, 17, 22 (Brilliant First Scarlet), 23, 31, 38, 48: 2 (Permanent Red 2B (Ba)), 48: 2 (Permanent Red 2B (Ca)), 48 : 3 (Permanent Red 2B (Sr)), 48: 4 (Permanent Red 2B (Mn)), 49: 1, 52: 2, 53: 1, 57: 1 (Brilliant Carmine 6B), 60: 1, 63: 1, 63: 2, 64: 1, 81 (Rhodamine 6G rake), 83, 88, 92, 101 (Bengara), 104, 105, 106, 108 (Cadmium red), 112, 114, 122 (Quinacridone magenta), 123, 146, 149, 166, 168, 170, 172, 177, 178, 179, 185, 190, 193, 209, 2 9; or C. I. Pigment Blue 1, 2, 15 (phthalocyanine blue R), 15: 1, 15: 2, 15: 3 (phthalocyanine blue G), 15: 4, 15: 6 (phthalocyanine blue E), 16, 17: 1, 56 , 60, 63; and the like.

  The particle diameter of the pigment is not particularly limited, but the average particle diameter is preferably 25 μm or less, more preferably 1 μm or less. By using a pigment having an average particle diameter of 25 μm or less, the occurrence of clogging can be suppressed, and further sufficient ejection stability can be realized.

  The content of the pigment is preferably 0.5 to 25% by weight, more preferably 2 to 15% by weight, based on the entire ink composition.

Thermoplastic resin:
In the present invention, the aqueous pigment ink composition comprises a thermoplastic resin. The thermoplastic resin can be appropriately selected and used in accordance with the description in the “thermoplastic resin” column of the above-described base solution.

  In the present invention, the thermoplastic resin may be mixed with other components in the ink composition as fine particle powder. However, after the resin fine particles are dispersed in an aqueous medium to form a resin emulsion, It is more preferable to mix with these components. When a thermoplastic resin is used as a pigment dispersant, it is preferably mixed with other components in the ink composition in the form of a pigment dispersion.

  The thermoplastic resin is preferably contained in the range of 0.1 to 30% by weight in terms of solid content, more preferably in the range of 0.3 to 15% by weight, based on the total amount of the aqueous pigment ink composition. preferable.

Water and other ingredients:
In the present invention, the aqueous pigment ink composition contains water. Here, water can be selected in accordance with the description in the column “Main solvent” of the above-mentioned base solution. In addition, the aqueous pigment ink composition includes other known components such as a penetrating agent and a humectant, as well as the “surfactant”, “low surface tension organic solvent”, “humectant” and “other components” of the above-described base liquid Can be appropriately selected and used in accordance with the description in the column.

  In the present invention, the water-based pigment ink composition is necessary after each of the above-mentioned blending components individually or in the form of a pigment dispersion or resin emulsion and appropriately mixed and dissolved (or dispersed) in any order. Depending on the condition, it can be prepared by filtering and removing impurities.

  According to another aspect of the present invention, there is provided a recorded matter printed by the ink jet recording method according to the present invention.

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

Preparation of base solution A base solution according to the present invention was prepared according to the following composition.
Base solution 1:
γ-butyrolactone 5.0% by weight
Styrene-acrylic acid copolymer 5.0% by weight (solid content)
Diethylene glycol 4.0 wt%
Diethylene glycol monobutyl ether 3.0% by weight
Surfinol 465 1.0 wt%
Pure water remaining

Base solution 2:
Propylene carbonate 5.0% by weight
Styrene-acrylic acid copolymer 5.0% by weight (solid content)
Diethylene glycol 4.0 wt%
Diethylene glycol monobutyl ether 3.0% by weight
Surfinol 465 1.0 wt%
Pure water remaining

Preparation of water-based pigment ink composition Water-based pigment ink compositions were prepared according to the following compositions.
Black ink:
Carbon black MA7 (Mitsubishi Kasei Co., Ltd.) 5.0 wt%
Styrene-acrylic acid copolymer (thermoplastic resin) 2.5 wt% (solid content)
Glycerin 3.0% by weight
Diethylene glycol 4.0 wt%
Diethylene glycol monobutyl ether 3.0% by weight
2-pyrrolidone 3.0 wt%
Surfinol 465 1.0 wt%
Pure water remaining

Cyan ink:
C. I. Pigment Blue 15: 3 2.0 wt%
Styrene-acrylic acid copolymer (thermoplastic resin) 1.0 wt% (solid content)
Glycerin 3.0% by weight
Diethylene glycol 6.0% by weight
Diethylene glycol monobutyl ether 3.0% by weight
2-pyrrolidone 3.0 wt%
Surfinol 465 1.0 wt%
Pure water remaining

Magenta ink:
C. I. Pigment Red 122 3.0 wt%
Styrene-acrylic acid copolymer (thermoplastic resin) 1.5% by weight (solid content)
Glycerin 3.0% by weight
Diethylene glycol 5.0% by weight
Diethylene glycol monobutyl ether 3.0% by weight
2-pyrrolidone 3.0 wt%
Surfinol 465 1.0 wt%
Pure water remaining

Yellow ink:
C. I. Pigment Yellow 74 2.0 wt%
Styrene-acrylic acid copolymer (thermoplastic resin) 1.0 wt% (solid content)
Glycerin 3.0% by weight
Diethylene glycol 6.0% by weight
Diethylene glycol monobutyl ether 3.0% by weight
2-pyrrolidone 3.0 wt%
Surfinol 465 1.0 wt%
Pure water remaining

Evaluation test
Creating print samples (Examples 1-5):
A base solution 1 or a base solution 2 is applied to a soft vinyl chloride film (Scotch film; manufactured by Sumitomo 3M Co., Ltd.) that has not been subjected to surface treatment exclusively for ink jet printing using an inkjet printer (TM-J8000; manufactured by Seiko Epson Corporation). Was applied at 50% duty. Then, it dried for 1 hour with the thermostat of 60 degreeC and relative humidity 20%, and formed the base film. Next, a 100% duty pattern was printed using an inkjet printer (TM-J8000; manufactured by Seiko Epson Corporation) filled with black ink, cyan ink, magenta ink, or yellow ink.
The printed sample was dried in a thermostatic bath at 60 ° C. and a relative humidity of 20% for 1 hour and further at room temperature for 1 day, and then subjected to the following evaluation test.

Preparation of print samples (Examples 6 to 9 (comparative examples)):
Using an inkjet printer (TM-J8000; manufactured by Seiko Epson Corporation) filled with black ink, cyan ink, magenta ink, or yellow ink, 100% is applied to the same soft vinyl chloride film (without application of the base solution) as in Example 1. A duty pattern was printed. This was dried in a thermostatic bath at 60 ° C. and a relative humidity of 20% for 1 hour and further at room temperature for 1 day, and then subjected to the following evaluation test.

Sample evaluation
Evaluation 1: Scratch resistance and scratch resistance A pencil with a printed film was removed using a 750 g load pencil scratch tester (manufactured by Imoto Seisakusho Co., Ltd.) specified in JIS K-5600-5-4 for pencils of each hardness. The presence or absence of scratches (cohesive failure) was examined. The results were evaluated according to the following criteria.
A: The HB hardness pencil is not damaged and the substrate does not appear.
B: Although the foundation | substrate appears by being damaged with a HB hardness pencil, a foundation | substrate does not appear with a B hardness pencil.
C: The groundwork appears after being damaged by a B hardness pencil.

Evaluation 2: An adhesive pressure-sensitive adhesive tape (Cello Tape No. 252; manufactured by Sekisui Chemical Co., Ltd.) was applied to the printing part of the print sample and rubbed with a finger two to three times, and then the pressure-sensitive adhesive tape was peeled off. The state of the printed part of the part was visually observed. The results were evaluated according to the following criteria.
A: There is no peeling of the ink (colorant) from the vinyl chloride film.
B: Part of the ink (colorant) peels from the vinyl chloride film.
C: The ink (colorant) is completely peeled from the vinyl chloride film.

Evaluation 3: One drop of tap water was allowed to adhere to the printing portion of the water- resistant print sample and left for 1 minute, and then the water drop was wiped off with gauze. The state of the printed part and gauze after wiping off was visually observed. The results were evaluated according to the following criteria.
A: There is no peeling of the ink (colorant) from the vinyl chloride film, and the gauze is not colored.
B: A part of the ink (colorant) is peeled off from the vinyl chloride film, and the gauze is colored.
C: The ink (colorant) is completely peeled from the vinyl chloride film, and the gauze is colored.

  The results were as shown in Table 1 below.

Claims (22)

A printing ground solution for an inkjet recording medium, wherein the recording surface is a plastic film, comprising at least a cyclic ester compound of the following formula (I), a thermoplastic resin, and a main solvent, wherein the thermoplastic resin is a ground solution: Print base solution dispersed in:

[Where:
R represents a linear or branched C2-12 saturated hydrocarbon chain, and X represents —CH ₂ — or —O—.   The base solution according to claim 1, wherein the main solvent is water.   The base solution according to claim 1 or 2, further comprising a surfactant and / or a low surface tension organic solvent.   The base solution according to any one of claims 1 to 3, further comprising a surfactant, or further comprising a surfactant and a low surface tension organic solvent.   The base solution according to any one of claims 1 to 4, wherein in formula (I), R represents a linear or branched C2-5 saturated hydrocarbon group.   The base solution according to any one of claims 1 to 5, wherein the cyclic ester compound is selected from the group consisting of γ-butyrolactone, ε-caprolactone, propylene carbonate, and ethylene carbonate.   The base solution according to any one of claims 1 to 6, further comprising a wetting agent.   The base solution according to any one of claims 3 to 7, wherein the surfactant is an acetylene glycol surfactant.   The base solution according to any one of claims 3 to 8, wherein the low surface tension organic solvent is diethylene glycol monobutyl ether or triethylene glycol monobutyl ether. The cyclic ester compound content is 0.1 to 40.0% by weight,
The content of the thermoplastic resin is 0.1 to 15.0% by weight in terms of solid content, and
The base solution according to any one of claims 3 to 9, wherein the content of the surfactant is 0.01 to 5.0% by weight.   The base solution according to any one of claims 1 to 10, which is applied to a recording medium by an inkjet recording method.   The base solution according to any one of claims 1 to 11, which is used to form a base film by coating on a recording medium before printing the ink composition. The ink composition is an aqueous pigment ink composition comprising at least a pigment, a thermoplastic resin, and water, and the thermoplastic resin contained in the base liquid and the thermoplastic contained in the aqueous pigment ink composition. The base solution according to claim 12, wherein the resin is the same component. A printing base set according to any one of claims 1 to 12, an ink jet recording set comprising an aqueous pigment ink composition comprising at least a pigment, a thermoplastic resin, and water.   The set according to claim 14, wherein the thermoplastic resin contained in the base solution and the thermoplastic resin contained in the ink composition are the same component. An ink jet recording method in which a base liquid is applied to a recording medium having a recording surface made of a plastic film to form a base film, and then droplets of the ink composition are ejected and adhered to the base film for printing. And
An aqueous pigment ink composition, wherein the base solution is the printing base solution according to any one of claims 1 to 10, and the ink composition comprises at least a pigment, a thermoplastic resin, and water. An inkjet recording method.   The method according to claim 16, wherein the thermoplastic resin contained in the base liquid is the same component as the thermoplastic resin contained in the ink composition.   The method according to claim 16 or 17, wherein the base liquid is applied by an ink jet recording method in which the droplets are ejected and adhered to a recording surface of a recording medium. Before applying the ink composition,
The method according to any one of claims 16 to 18, further comprising a drying step of evaporating moisture of the applied base solution to form a base film.   The method according to any one of claims 16 to 19, further comprising a heating step of heating the ink composition adhered to the recording surface to form a resin film.   The method according to claim 20, wherein the drying treatment in the drying step and / or the heat treatment in the heating step is performed by heater heating or hot air drying.   Recorded matter printed by the method according to any one of claims 16 to 21.