JP2023131699A - Composition and printing method - Google Patents

Abstract

To provide a stable composition which is excellent in adhesion to a base material.SOLUTION: A composition contains at least (A) a monofunctional polymerizable compound, (B) a photopolymerization initiator, and (C) a chlorinated polyolefin resin, wherein (A) the monofunctional polymerizable compound contains (A-1) a monofunctional polymerizable compound having an alicyclic hydrocarbon group, and (A-2) a monomer represented by the following structural formula (1), the amounts of the component (A-1) and the component (C) contained in the composition satisfy a relation of amount of component (A-1)/amount of component (C)≥2.0, the amount of (A) the monofunctional polymerizable compound in the polymerizable compound contained in the composition is within a range of 70-100 mass%, and the amount of the component (A-1) in the polymerizable compound is 25 mass% or more.SELECTED DRAWING: None

Description

The present invention relates to a composition and a printing method using the composition, and particularly to a stable composition that has excellent adhesion to a substrate.

In recent years, with improvements in printing technology using inkjet printers and the like, printed matter with various designs has become widespread. In particular, photocurable inks that are cured by active energy rays or the like are used for printing on various substrates because they dry quickly and can provide images with little bleeding.

JP-A-2013-142104 (Patent Document 1) describes an invention related to an energy ray-curable inkjet ink composition containing a colorant and a polymerizable monomer. In Patent Document 1, a monofunctional monomer having an aromatic hydrocarbon-based cyclic structure in the molecule and a monofunctional monomer having an aliphatic hydrocarbon-based cyclic structure in the molecule are used, and 90% by mass or more of the polymerizable monomer is used. By using it as a monofunctional monomer, it has excellent adhesion to recording media made of various materials, and furthermore, it has energy ray curing that allows the printed image to have unprecedented flexibility and stretchability. It is described that type inkjet ink compositions can be provided.

Further, when printing ink to form an image on a recording medium, a method is known in which a primer is printed in advance in order to improve the fixability of the formed image.

JP-A No. 2012-140615 (Patent Document 2) discloses that an N-vinyllactam compound, an acrylamide compound, or an N-vinylamide compound is used as an adhesive component in a primer ink containing 2-hydroxy-3-phenoxypropyl acrylate. It is described that this can improve the fixability of images formed with inkjet ink printed after the primer to various non-absorbent recording media.

JP 2018-159038 A (Patent Document 3) discloses that chlorinated polyolefin, a monofunctional monomer with a glass transition temperature (Tg) of 0°C or lower, and a monofunctional monomer with a glass transition temperature (Tg) of 60°C or higher are used in specific amounts. The present invention relates to a photocurable inkjet printing ink composition containing: Patent Document 3 describes that this photocurable inkjet printing ink composition is a composition for a primer used on the surface of a polyolefin molded article, and has the effect of having sufficient adhesion to the polyolefin molded article. , it is stated that the effect of low tackiness of the ink coating film can be achieved in a well-balanced manner.

Japanese Patent Application Publication No. 2013-142104 Japanese Patent Application Publication No. 2012-140615 JP 2018-159038 Publication

Therefore, an object of the present invention is to provide a stable composition that has excellent adhesion to substrates. Another object of the present invention is to provide a printing method using such a composition.

As a result of intensive studies to achieve the above object, the present inventors have determined that, in a composition containing a polymerizable compound and a photopolymerization initiator, the ratio of the monofunctional polymerizable compound in the polymerizable compound is increased, and alicyclic By using a monofunctional polymerizable compound having a hydrocarbon group and a chlorinated polyolefin resin in a specific mass ratio, and using a monomer represented by the following structural formula (1), a wide range of base materials such as metals, glass, and plastics can be used. The present inventors have discovered that good adhesion can be ensured against the surface of the film, and have completed the present invention. In addition, if the amount of the monofunctional polymerizable compound having an alicyclic hydrocarbon group in the polymerizable compound is small, or if the amount of the monofunctional polymerizable compound having an alicyclic hydrocarbon group with respect to the chlorinated polyolefin resin is small, , the chlorinated polyolefin resin was not sufficiently dissolved and became cloudy in a short period of time, so from the perspective of providing a stable composition, the amount of monofunctional polymerizable compound having an alicyclic hydrocarbon group was secured. I found it important to do so.

（ここで、Ｒ^１は、水素原子またはメチル基であり、Ｒ^２は、炭素数が１以上のアルキレン基であり、ｎ１は、１以上の整数であり、ｎ２は、０または１以上の整数である）で表されるモノマーを含み、前記組成物中に含まれる成分（Ａ－１）と成分（Ｃ）の量（質量％）が、下記（式１）：
成分（Ａ－１）の量／成分（Ｃ）の量 ≧２．０ （式１）
の関係を満たし、前記組成物に含まれる重合性化合物中の単官能重合性化合物の量が７０質量％～１００質量％の範囲内であり、前記重合性化合物中の成分（Ａ－１）の量が２５質量％以上であることを特徴とする組成物である。 Therefore, the composition of the present invention is a composition containing at least (A) a monofunctional polymerizable compound, (B) a photopolymerization initiator, and (C) a chlorinated polyolefin resin, (A-1) A monofunctional polymerizable compound having an alicyclic hydrocarbon group, and (A-2) Structural formula (1)

(Here, R ¹ is a hydrogen atom or a methyl group, R ² is an alkylene group having 1 or more carbon atoms, n1 is an integer of 1 or more, and n2 is 0 or an integer of 1 or more. The amount (% by mass) of component (A-1) and component (C) contained in the composition is as follows (Formula 1):
Amount of component (A-1)/amount of component (C) ≧2.0 (Formula 1)
the amount of the monofunctional polymerizable compound in the polymerizable compound contained in the composition is within the range of 70% by mass to 100% by mass, and the amount of component (A-1) in the polymerizable compound is within the range of 70% by mass to 100% by mass. The composition is characterized in that the amount thereof is 25% by mass or more.

In a preferred embodiment of the composition of the present invention, at least 30% by mass of component (A-1) is a monofunctional polymerizable compound having an alicyclic hydrocarbon group selected from those other than isobornyl acrylate.

In another preferred embodiment of the composition of the present invention, the amount of component (A-2) in the polymerizable compound is 5 to 50% by mass.

In another preferred embodiment of the composition of the present invention, the total amount of component (A-1) and component (A-2) is 50% by mass or more of the total amount of the composition.

In another preferred embodiment of the composition of the present invention, component (A-1) contains at least t-butylcyclohexyl acrylate or trimethylcyclohexyl acrylate.

In another preferred example of the composition of the present invention, component (A-2) contains any one of ethoxydiethylene glycol acrylate, methoxydipropylene glycol acrylate, 2-ethylhexyldiethylene glycol acrylate, and methoxytripropylene glycol acrylate.

Moreover, the printing method of the present invention is a printing method characterized by printing the above-described composition of the present invention as a primer ink, photocuring it, and then printing a color ink and/or a clear ink.

In a preferred embodiment of the printing method of the present invention, the printed color ink and/or clear ink covers 90% or more of the surface of the photocured composition layer.

According to the composition of the present invention, a stable composition with excellent adhesion to a substrate can be provided. Moreover, according to the printing method of the present invention, a printing method using such a composition can be provided.

The present invention will be explained in detail below. The present invention relates to compositions and printing methods.

One embodiment of the present invention is a composition that includes at least (A) a monofunctional polymerizable compound, (B) a photopolymerization initiator, and (C) a chlorinated polyolefin resin. This composition is also referred to herein as the "composition of the invention."

The composition of the present invention contains a polymerizable compound. Polymerizable compounds are polymerizable through functional groups that exhibit reactivity when irradiated with active energy rays (for example, polymerizable unsaturated groups such as carbon-carbon double bonds constituting acryloyl groups, methacryloyl groups, vinyl groups, or allyl groups). A compound that causes a polymerization reaction. The polymerizable compounds may be used alone or in combination of two or more. The amount of polymerizable compound in the composition of the invention is preferably 70 to 95% by weight.

Polymerizable compounds are classified as monofunctional polymerizable compounds or polyfunctional polymerizable compounds. Here, monofunctional polymerizable compounds include monofunctional polymerizable monomers having one functional group that exhibits reactivity upon irradiation with active energy rays (for example, monofunctional polymerizable monomers having one polymerizable unsaturated group), and active energy rays. Examples include monofunctional polymerizable oligomers having one functional group that exhibits reactivity upon energy ray irradiation (for example, monofunctional polymerizable oligomers having one polymerizable unsaturated group). Examples of polyfunctional polymerizable compounds include polyfunctional polymerizable monomers that have two or more functional groups that exhibit reactivity when irradiated with active energy rays (e.g., polyfunctional polymerizable monomers that have two or more polymerizable unsaturated groups), and activated Examples include polyfunctional polymerizable oligomers having two or more functional groups that exhibit reactivity upon energy ray irradiation (for example, polyfunctional polymerizable oligomers having two or more polymerizable unsaturated groups).

The composition of the present invention contains at least a monofunctional polymerizable compound as a polymerizable compound. In this specification, the monofunctional polymerizable compound is also referred to as "(A) monofunctional polymerizable compound" or "component (A)." The monofunctional polymerizable compounds may be used alone or in combination of two or more. The amount of the monofunctional polymerizable compound in the polymerizable compound is preferably in the range of 70% by mass or more, more preferably in the range of 85% by mass or more, and 95% by mass to 100% by mass. is even more preferable. By increasing the proportion of the monofunctional polymerizable compound contained in the polymerizable compound, a film with excellent flexibility and good adhesion can be obtained.

As used herein, the term (meth)acrylate means methacrylate or acrylate. In addition, when a prefix indicating plurality is attached to a (meth)acrylate, such as di(meth)acrylate, tri(meth)acrylate, etc., each (meth)acrylate may be the same or different. good.

As the monofunctional polymerizable compound, it is preferable to use monomers that do not leave an odor on printed materials when used in places that are visible to people, such as outdoor advertisements and plastic boards. For example, ethoxydiethylene glycol acrylate, N-acryloyl Examples include morpholine, N-methacryloylmorpholine, t-butylcyclohexyl acrylate, trimethylcyclohexyl acrylate, and the like.

In the composition of the present invention, the monofunctional polymerizable compound preferably contains a monofunctional polymerizable compound having an alicyclic hydrocarbon group from the viewpoint of adhesion. In this specification, the monofunctional polymerizable compound having an alicyclic hydrocarbon group is also referred to as "(A-1) Monofunctional polymerizable compound having an alicyclic hydrocarbon group" or "component (A-1)." . Moreover, the monofunctional polymerizable compound having an alicyclic hydrocarbon group also has excellent compatibility with the chlorinated polyolefin resin described below. Alicyclic hydrocarbon group means an alicyclic structure (saturated or unsaturated carbon ring having no aromaticity), for example, a cycloalkyl group, preferably a C _4-20 cycloalkyl group, more preferably a C _{4 -10} cycloalkyl group. Examples of monofunctional polymerizable compounds having an alicyclic hydrocarbon group include cycloalkyl (meth)acrylates such as cyclohexyl (meth)acrylate, 4-methylcyclohexyl (meth)acrylate, t-butylcyclohexyl acrylate, and trimethylcyclohexyl acrylate. Cycloalkylalkyl (meth)acrylates such as alkylcycloalkyl (meth)acrylates, cyclohexylmethyl (meth)acrylate, cyclohexylethyl (meth)acrylate, cyclohexylpropyl (meth)acrylate, 4-methylcyclohexylmethyl (meth)acrylate, Examples include crosslinked cyclic (meth)acrylates such as isobornyl (meth)acrylate and adamantyl (meth)acrylate. Among these, t-butylcyclohexyl acrylate and trimethylcyclohexyl acrylate are particularly preferred. The monofunctional polymerizable compound having an alicyclic hydrocarbon group may be used alone or in combination of two or more. The amount of the monofunctional polymerizable compound having an alicyclic hydrocarbon group in the polymerizable compound is preferably in the range of 25% by mass or more, more preferably 45 to 70% by mass or more. Note that if the amount of the monofunctional polymerizable compound having an alicyclic hydrocarbon group in the polymerizable compound is too small, the chlorinated polyolefin resin will not be sufficiently dissolved, and there is a risk that cloudiness will occur in a short period of time.

In the composition of the present invention, at least 30% by mass or more of the monofunctional polymerizable compound having an alicyclic hydrocarbon group is a monofunctional polymerizable compound having an alicyclic hydrocarbon group selected from those other than isobornyl acrylate. Preferably, it is a compound.

In the composition of the present invention, the polymerizable compound preferably contains a monofunctional polymerizable compound that is difficult to dry from the viewpoint of adhesion and discharge properties. Specifically, monofunctional polymerizable compounds having an ethylene glycol or propylene glycol structure are preferred, such as ethoxydiethylene glycol acrylate, methoxydipropylene glycol acrylate, methoxytriethylene glycol acrylate, phenoxyethyl acrylate, and phenoxyethyl diethylene glycol acrylate. etc.

In the composition of the present invention, the monofunctional polymerizable compound preferably contains a monofunctional polymerizable compound having an alicyclic hydrocarbon group whose homopolymer Tg is 80° C. or less. Examples of the monofunctional polymerizable compound having an alicyclic hydrocarbon group with a homopolymer Tg of 80° C. or less include t-butylcyclohexyl acrylate, trimethylcyclohexyl acrylate, and the like. Monofunctional polymerizable compounds having an alicyclic hydrocarbon group with a homopolymer Tg of 80° C. or less may be used alone or in combination of two or more. A monofunctional polymerizable compound having a homopolymer Tg of 80° C. or less and having an alicyclic hydrocarbon group has a strong sticky feeling during polymer formation and is excellent in adhesion. The amount of the monofunctional polymerizable compound having an alicyclic hydrocarbon group with a homopolymer Tg of 80°C or less in the polymerizable compound is preferably 10% by mass or more, and within the range of 15 to 80% by mass. It is more preferable that there be.

The glass transition temperature (Tg) of a homopolymer is common technical knowledge, but when using a monomer whose glass transition temperature is unknown, the glass transition temperature of the monomer can be determined by differential scanning calorimetry (DSC) or differential calorimetry. (DTA), thermomechanical analysis (TMA), etc.

（ここで、Ｒ^１は、水素原子またはメチル基であり、Ｒ^２は、炭素数が１以上のアルキレン基であり、ｎ１は、１以上の整数であり、ｎ２は、０または１以上の整数である）で表されるモノマーを含むことが好ましい。構造式（１）で表されるモノマーは、粘着性の確保に効果を有する。本明細書では、構造式（１）で表されるモノマーを「（Ａ－２）構造式（１）で表されるモノマー」または「成分（Ａ－２）」とも称する。成分（Ａ－２）は、一種単独で用いてもよく、二種以上を組み合わせて用いてもよい。 In the composition of the present invention, the monofunctional polymerizable compound has the structural formula (1)

(Here, R ¹ is a hydrogen atom or a methyl group, R ² is an alkylene group having 1 or more carbon atoms, n1 is an integer of 1 or more, and n2 is 0 or an integer of 1 or more. It is preferable to include a monomer represented by The monomer represented by structural formula (1) is effective in ensuring adhesiveness. In this specification, the monomer represented by structural formula (1) is also referred to as "(A-2) monomer represented by structural formula (1)" or "component (A-2)." Component (A-2) may be used alone or in combination of two or more.

In structural formula (1), R ¹ is a hydrogen atom or a methyl group. R ² is an alkylene group having 1 or more carbon atoms, preferably an alkylene group having 1 to 4 carbon atoms. Examples of R ² include a methylene group, an ethylene group (or a dimethylene group), a propylene group, and a trimethylene group. n1 is an integer of 1 or more, preferably 2 or more. n2 is an integer of 0 or 1 or more, preferably 0 or 1.

Examples of the monomer represented by structural formula (1) include methoxydipropylene glycol (meth)acrylate, methoxytriethylene glycol (meth)acrylate, ethoxydiethylene glycol (meth)acrylate, 2-ethylhexyldiethylene glycol (meth)acrylate, Examples include methoxytripropylene glycol (meth)acrylate. The monomer represented by structural formula (1) preferably contains any one of ethoxydiethylene glycol acrylate, methoxydipropylene glycol acrylate, 2-ethylhexyldiethylene glycol acrylate, and methoxytripropylene glycol acrylate.

The amount of component (A-2) in the polymerizable compound is preferably within the range of 5 to 50% by mass, more preferably within the range of 10 to 40% by mass.

In the composition of the present invention, the total amount of component (A-1) and component (A-2) is preferably 50% by mass or more of the total amount of the composition.

In the composition of the present invention, the monofunctional polymerizable compound may include a nitrogen atom-containing monofunctional polymerizable compound, and preferably includes a monomer having a (meth)acrylamide structure. A monomer having a (meth)acrylamide structure makes it difficult for the composition to dry in the head portion of a printing device, so it has the effect of improving re-discharge properties.

Although nitrogen atom-containing monofunctional polymerizable compounds have excellent re-discharge properties, they have poor storage stability and adhesion to substrates, so the amount of nitrogen atom-containing monofunctional polymerizable compounds in the polymerizable compound must be 10% by mass or less. is preferable, and more preferably within the range of 0 to 5% by mass.

The composition of the present invention contains a photoinitiator. The photopolymerization initiator has the effect of starting the polymerization of the above-mentioned polymerizable compound when irradiated with active energy rays. In this specification, the photopolymerization initiator is also referred to as "(B) photopolymerization initiator" or "component (B)." Component (B) may be used alone or in combination of two or more. The amount of photopolymerization initiator in the composition of the present invention is preferably 1 to 25% by weight, more preferably 3 to 20% by weight, even more preferably 3 to 15% by weight. If the content of the photopolymerization initiator is less than 1% by mass, the film may be poorly cured, and if it exceeds 25% by mass, precipitates may occur at low temperatures, making the composition unstable to discharge. be. Furthermore, in order to accelerate the initiation reaction of the photopolymerization initiator, it is also possible to use an auxiliary agent such as a photosensitizer.

Examples of the photopolymerization initiator include benzophenone compounds, acetophenone compounds, thioxanthone compounds, and phosphine oxide compounds, but from the viewpoint of curability, the wavelength of the active energy ray to be irradiated and the photopolymerization initiator It is preferable that the absorption wavelengths of the two overlap as much as possible. In particular, the photopolymerization initiator preferably includes an acylphosphine oxide initiator from the viewpoint of LED curing and coloring during curing.

The composition of the present invention includes a chlorinated polyolefin resin. Chlorinated polyolefin resin is a resin that greatly contributes to ensuring adhesion to substrates, and when combined with (A-1) a monofunctional polymerizable compound having an alicyclic hydrocarbon group, it can be used to bond glass, metals, and plastics. It is possible to obtain a composition that has excellent adhesion to a wide range of substrates such as. In addition, the surface of the cured film obtained from the composition containing the chlorinated polyolefin resin and component (A-1) remains tacked, and therefore the adhesion to the layer printed subsequently can be improved. . The chlorinated polyolefin resin is preferably a resin that does not have a functional group that exhibits reactivity upon irradiation with active energy rays. In this specification, the chlorinated polyolefin resin is also referred to as "(C) chlorinated polyolefin resin" or "component (C)." Component (C) may be used alone or in combination of two or more.

The amounts (mass%) of component (A-1) and component (C) contained in the composition of the present invention preferably satisfy relational expression (1), and more preferably satisfy relational expression (2). .
・Relational expression (1): Amount of component (A-1)/Amount of component (C) ≧ 2.0
・Relational expression (2): Amount of component (A-1)/Amount of component (C) ≧ 5
Even when chlorinated polyolefin resin and component (A-1) are used together, if the value of "mass of component (A-1)/mass of component (C)" is less than 2, the resin will not dissolve in the composition. do not.

The amount of chlorinated polyolefin resin in the composition of the invention is preferably from 0.1 to 15% by weight, more preferably from 1 to 10% by weight.

A chlorinated polyolefin resin is a resin obtained by chlorinating a polyolefin or an acid-modified product thereof, and at least a portion of the hydrogen in the polyolefin or an acid-modified product thereof is replaced with chlorine. For example, methods for chlorinating polyolefin resin include dissolving polyolefin or its acid-modified product in an organic solvent as needed, blowing chlorine gas, and introducing chlorine atoms into the polyolefin or its acid-modified product. Are known. A radical reaction initiator may be used when blowing chlorine gas.

The chlorinated polyolefin resin may be acid-modified. In this specification, a chlorinated polyolefin resin or a raw material polyolefin resin that has been acid-modified is also referred to as an acid-modified chlorinated polyolefin resin. The acid modification treatment can be carried out by a known method. For example, a chlorinated polyolefin resin or a polyolefin resin, an α,β-unsaturated carboxylic acid or a derivative thereof is dissolved in an organic solvent as necessary, and a radical generator is added. Examples include a method of adding .

The composition of the invention may also include a radical scavenger. A radical scavenger can capture free radicals and the like and improve photostability. Further, in the present invention, a substance having a function of reacting with free radicals and preventing a polymerization reaction from occurring (so-called polymerization inhibitor) is also included in the radical scavenger in the present invention. The radical scavengers may be used alone or in combination of two or more.

Examples of the radical scavenger include hindered amine compounds, hydroquinone compounds, phenol compounds, phenothiazine compounds, nitroso compounds, and N-oxyl compounds, with phenol compounds being particularly preferred.

The composition of the present invention may contain a coloring agent such as a dye or a pigment, but in that case, it is preferable to contain a pigment from the viewpoint of weather resistance. The content of the colorant is, for example, 0.1 to 15% by mass in the composition. The coloring agents may be used alone or in combination of two or more.

Coloring agents also include aluminum flakes, glass flakes, and pearlescent pigments.

The composition of the present invention may contain various compounds for the purpose of imparting functionality. For example, it may contain calcium carbonate, barium sulfate, etc. in order to increase the altitude of the obtained film. Nanoparticles such as tin-doped indium oxide (ITO), antimony-doped tin oxide (ATO), and gold silver may be contained in order to impart a heat ray absorption function to the film, and oxidation may be added to adjust the refractive index of the resulting film. It may also contain titanium, zirconium oxide, hollow particles, etc.

From the viewpoint of ejection stability, the pigment particles dispersed in the composition preferably have a volume average particle diameter of 0.05 to 0.4 μm and a volume maximum particle diameter of 0.2 to 1 μm. When the volume average particle size is larger than 0.4 μm and the volume maximum particle size is larger than 1 μm, it tends to be difficult to stably discharge the composition. The volume average particle diameter and the maximum volume particle diameter can be measured by a measuring device using a dynamic light scattering method.

The composition of the present invention may further contain a pigment dispersant, if necessary, in order to disperse the pigment. The content of the pigment dispersant is, for example, 0.1 to 5% by mass in the composition. Pigment dispersants may be used alone or in combination of two or more.

The composition of the present invention may further contain a surface conditioner from the viewpoint of improving wettability. As used herein, the surface conditioning agent refers to a substance that has a hydrophilic site and a hydrophobic site in its molecular structure, and can adjust the surface tension of the composition by adding it.

Examples of surface conditioning agents include anionic surface conditioning agents such as dialkyl sulfosuccinates, alkylnaphthalene sulfonates, fatty acid salts, polyoxyethylene alkyl ethers, polyoxyethylene alkyl allyl ethers, acetylene glycols, and polyoxy Nonionic surface conditioning agents such as ethylene/polyoxypropylene block copolymers, cationic surface conditioning agents such as alkylamine salts and quaternary ammonium salts, acrylic surface conditioning agents, silicone surface conditioning agents, and fluorine surface conditioning agents. agents, etc. In particular, from the viewpoint of recoatability, it is preferable to use a surface conditioning agent other than a silicon-based surface conditioning agent.

The amount of the surface conditioner can be appropriately selected depending on the purpose of use, but it is preferably 0.01 to 3% by mass in the composition, for example. The surface conditioning agents may be used alone or in combination of two or more.

The composition of the present invention contains other resins, antioxidants, plasticizers, rust preventives, solvents, fillers, antifoaming agents, charge control agents, stress relaxation agents, penetrants, and light guide materials as other components. Additives such as bright materials, magnetic materials, phosphors, antibacterial agents, antiviral agents, and algaecides may be used as necessary.

Preferably, the composition of the invention is a primer composition. As used herein, the term "primer composition" refers to a composition that is first applied to a base material when printing or the like. By first printing the composition of the present invention on a substrate as a primer, the adhesion of the printed layer to the substrate can be improved.

The composition of the present invention is preferably a photocurable composition. In this specification, the photocurable composition means a composition that can be cured by irradiation with active energy rays such as ultraviolet rays, visible light, and electron beams.

The composition of the present invention can be obtained by mixing various components appropriately selected as necessary, and using a filter having a pore size of about 1/10 or less of the nozzle diameter of the inkjet print head to be used, as necessary. It can be prepared by filtering the mixture.

The composition of the present invention preferably has a viscosity at 40° C. of 5 to 25 mPa·s, more preferably 5 to 15 mPa·s. If the viscosity of the composition at 40° C. is within the range specified above, good ejection stability can be obtained. The viscosity of the composition can be measured using a cone-plate viscometer.

The composition of the present invention preferably has a static surface tension of 20 to 35 mN/m at 25°C. If the surface tension of the composition at 25° C. is within the range specified above, good ejection stability can be obtained. The surface tension of the composition can be measured by the plate method.

Another aspect of the present invention is a printing method in which the composition of the present invention described above is printed as a primer ink, photocured, and then color ink and/or clear ink is printed. In this specification, this printing method is also referred to as the "printing method of the present invention." In the printing method of the present invention, the composition of the present invention is printed as a primer, so it will also be referred to as a "primer composition" below.

The printing of the primer composition is preferably carried out by an inkjet printing method, but is not limited to this, and may be performed by a gravure printing method, an offset printing method, a flexographic printing method, a screen printing method, a coater method, a spray method, etc. It is also possible to perform this by various printing methods.

Various inkjet printers can be used for inkjet printing. Examples of the inkjet printer include an inkjet printer that ejects an ink composition using a charge control method or a piezo method. Furthermore, large-sized inkjet printers, specifically inkjet printers intended for printing on articles produced on industrial lines, can also be suitably used.

In the printing method of the present invention, the printed primer composition is photocured. Photocuring is performed by irradiation with active energy rays such as ultraviolet rays. As a result, a layer of a cured primer composition (primer layer) is formed. As a light source for active energy rays, a high-pressure mercury lamp, a metal halide lamp, an LED lamp, etc. can be used. Furthermore, the wavelength of the active energy ray irradiated to cure the primer layer preferably overlaps with the absorption wavelength of the photopolymerization initiator, and the main wavelength of the active energy ray is preferably 350 to 400 nm. The cumulative amount of active energy rays is preferably in the range of 100 to 2000 mJ/cm ² .

In the printing method of the present invention, the substrate on which the primer composition is printed is not particularly limited, but suitable examples include substrates used in industrial lines.

Examples of the base material include epoxy resin, ABS resin, polycarbonate, polyvinyl chloride, polystyrene, acrylic resin, and especially plastic base materials such as polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and polypropylene (PP). Metal base materials such as iron, stainless steel, aluminum, copper, titanium, and their alloys; non-metal inorganic base materials such as cement, concrete, gypsum, calcium silicate, calcium carbonate, marble, artificial marble, glass, and ceramic; and paper. Examples include base materials, wood base materials, and composite base materials that are a combination of two or more of these base materials.

The shape of the base material includes, for example, a film shape, a sheet shape, a plate shape, and the like. The surface of the base material may be smooth or may have unevenness. The surface of the base material may be subjected to pretreatment such as degreasing treatment, chemical conversion treatment, and polishing.

Specific examples of base materials include wood building materials such as veneer, plywood, particle board, and medium density fiberboard (MDF); ceramic siding boards, flexible boards, calcium silicate boards, gypsum slag barlite boards, wood chip cement boards, Ceramic building materials such as asbestos cement boards, pulp cement boards, precast concrete boards, lightweight aerated concrete (ALC) boards or ALC panels, and gypsum boards; various building materials (especially construction materials) such as metal siding boards, metal building materials such as aluminum, iron, and stainless steel; Plate) is preferably mentioned. Specific examples of base materials include PVC sheets, tarpaulin, plastic cardboard (plastic cardboard), plastic base materials such as acrylic boards, coated paper (specifically resin coated paper), art paper, cast paper, and slightly coated paper. Also included are paper base materials such as paper, wood-free paper, synthetic paper, and inkjet paper; and inorganic base materials such as tiles and glass plates.

Color ink is an ink for coloring a base material to draw characters or create designs such as images. Like the composition of the present invention, the color ink is preferably a photocurable composition, but it may be an organic solvent-based ink that uses an organic solvent as the main solvent or an aqueous ink that uses water as the main solvent. good.

The color ink may be composed of a plurality of color inks that emit different colors, and an example is a color ink that includes at least four types of ink: cyan ink, magenta ink, yellow ink, and black ink.

In this specification, the clear ink refers to an ink that has a light transmittance of 80% or more in the wavelength range of 380 to 800 nm when a film with a thickness of 30 μm is formed, and the light transmittance is preferably 90%. or more, more preferably 95% or more, still more preferably 97% or more. In the present specification, light transmittance is measured in accordance with JIS K7361-1:1997 "Plastic - Test method for total light transmittance of transparent materials - Part 1: Single beam method".

Similarly, the clear ink is preferably a photocurable ink, but it may also be an organic solvent-based ink that uses an organic solvent as the main solvent or an aqueous ink that uses water as the main solvent.

It is preferable that the color ink and the clear ink contain a polymerizable compound and a photopolymerization initiator. The color ink further includes a colorant. The clear ink can contain a colorant as long as it satisfies the above-mentioned light transmittance. Here, details of the polymerizable compound, photopolymerization initiator, and colorant are as described in the description of the composition of the present invention.

Other components of color ink and clear ink include resin, ultraviolet absorber, radical scavenger, pigment dispersant, surface conditioner, antioxidant, plasticizer, rust preventive, solvent, filler, antifoaming agent, Additives such as charge control agents, stress relaxation agents, penetrating agents, light guide materials, glitter materials, magnetic materials, fluorescent materials, antibacterial agents, antiviral agents, and algaecides may be used as necessary. Here, details of the resin, ultraviolet absorber, radical scavenger, pigment dispersant, and surface conditioner are as described in the description of the composition of the present invention.

Examples of printing methods for color ink and clear ink include various printing methods such as an inkjet printing method, a gravure printing method, an offset printing method, a flexo printing method, a screen printing method, a coater method, and a spray method. It is preferable that

In the printing method of the present invention, printing of color ink and/or clear ink is performed on a cured primer layer. Here, printing of color ink and clear ink means printing color ink and clear ink simultaneously or sequentially. For example, there is a method of printing color ink and then printing clear ink on the cured primer layer.

When the color ink and clear ink are photocurable inks, after printing the color ink and/or clear ink, the printed color ink and/or clear ink is photocured. For example, there is a method of printing color ink on a cured primer layer, photo-curing it, and then printing clear ink and photo-curing it.

In the printing method of the present invention, it is preferable that the color ink and/or the clear ink cover 90% or more of the surface of the cured primer composition layer (primer layer).

EXAMPLES The present invention will be described in more detail below with reference to Examples, but the present invention is not limited to the Examples below.

<Preparation of primer composition> (Example 1-26, Comparative Example 1-10)
Each component was mixed in the ratios shown in Tables 2 to 5, stirred at 60°C for 12 hours, and then filtered through a filter with a captured particle size of 1 μm or less to prepare a primer composition.
Below, details of the components shown in the table are shown. Note that the formulation shown in the table is expressed in mass %.
<Polymerizable compound>
(A-1) Monofunctional polymerizable compound having an alicyclic hydrocarbon group/IBXA: Isobornyl acrylate, Osaka Organic Chemical Industry Co., Ltd., Tg 97°C as a homopolymer
・TBCHA: 4-tert-butylcyclohexyl acrylate, Sartomer, homopolymer Tg 38°C
・TMCHA: 3,3,5-trimethylcyclohexyl acrylate, Sartomer, homopolymer Tg 29°C
(A-2) Monomer represented by structural formula (1)・EC-A: Ethyl carbitol acrylate, Kyoeisha Chemical Co., Ltd.・DPMA: Methyldipropylene glycol acrylate, Kyoeisha Chemical Co., Ltd.・EHDG-AT: 2-ethylhexyl Diethylene glycol acrylate, Kyoeisha Chemical Co., Ltd./MTG-A: Methyltriethylene glycol acrylate, Kyoeisha Chemical Co., Ltd. (other monofunctional polymerizable compounds)
・POA: Phenoxyethyl acrylate, Kyoeisha Chemical Co., Ltd. ・THFA: Tetrahydrofurfuryl acrylate, Kyoeisha Chemical Co., Ltd. (multifunctional polymerizable compound)
・Aronix M6250: Bifunctional polyester acrylate, Toagosei Co., Ltd. ・9EG-A: PEG400 diacrylate, Kyoeisha Chemical Co., Ltd. ・TMPEOTA: Trimethylolpropane EO addition triacrylate, Daicel Allnex Co., Ltd. <Resin>
・SC3228S: Acid-modified chlorinated polyolefin, Nippon Paper Industries Co., Ltd., chlorination rate 28%
・SC3221S: Acid-modified chlorinated polyolefin, Nippon Paper Industries Co., Ltd., chlorination rate 21%
・SC814HS: Chlorinated polyolefin, Nippon Paper Industries Co., Ltd., chlorination rate 41%
・SC390S: Chlorinated polyolefin, Nippon Paper Industries Co., Ltd., chlorination rate 36%
・SC2319S: Chlorinated polyolefin, Nippon Paper Industries Co., Ltd., chlorination rate 19.5%
・CAB551-0.01: Cellulose resin, Eastman Chemical Company ・Addbond LTH: Modified polyester resin, Evonik Company, Dianal BR-83: Acrylic resin, Mitsubishi Chemical Corporation <Photopolymerization initiator>
・TPO: Omnirad TPO, IGM <Surface conditioning agent>
・PF90: Polyflow No. 90, Kyoeisha Chemical Co., Ltd. <Polymerization inhibitor>
・MEHQ: Methoquinone, Seiko Chemical Co., Ltd.

The primer composition was evaluated as follows. The results are shown in Tables 2 to 5.

<Initial appearance>
The prepared primer composition was visually evaluated. The evaluation criteria are as follows.
○: Completely dissolved ×: There is some undissolved material

<Stability>
After the primer composition was prepared, the appearance was visually evaluated after being left at 25° C. for a maximum of 2 weeks using the following criteria.
Evaluation criteria 〇: No change in appearance after 2 weeks △: No cloudiness after 3 days and cloudiness after 2 weeks ×: Cloudiness after 3 days Note that primer compositions with a stability rating of “×” were not compared to other No evaluation was performed.

<Adhesion>
After applying the primer composition onto the substrate using a bar coater #5, 385 nm light was irradiated with an LED lamp at 2000 mW/cm ² and 1000 mJ/cm ² . Thereafter, the ink listed in Table 1 was formed on the cured primer composition layer under the same conditions as the primer composition so as to cover 100% of the surface of the layer, and adhered in accordance with JIS K5600 5-6. The test was conducted. A polypropylene base material and a glass base material were used as the base materials. Adhesion was evaluated based on the following criteria. In Tables 2 to 5, the evaluation results for polypropylene substrates are shown in "Adhesion (PP)" and the evaluation results for glass substrates are shown in "Adhesion (Glass)."
Evaluation criteria ◎: The edges of the cut are completely smooth and there is no peeling ○: There is peeling only at the cut parts and corners △: Cases other than ◎, ○, and × ×: Completely peeled

Below, details of the components shown in the table are shown. Note that the formulation shown in the table is expressed in mass %.
・Pig. Bk7 20% THFA dispersion: 20% by mass tetrahydrofurfuryl acrylate dispersion of carbon black・ACMO: Acryloylmorpholine, KJ Chemicals Co., Ltd.・POA: Phenoxyethyl acrylate, Kyoeisha Chemical Co., Ltd.・THFA: Tetrahydrofurfuryl acrylate, Kyoeisha Chemical Co., Ltd. Kagaku Co., Ltd.・EBECRYL 8402: Urethane acrylate, manufactured by Daicel Ornex Corporation・PI-718: 2,4,6-trimethylbenzoyl-diphenylphosphine oxide, manufactured by IGM Polymerization initiator・DETX: Omnirad DETX, 2,4- Diethylthioxanthone, IGM polymerization initiator/BYK UV3500: BYK surfactant

<Dischargeability>
Using the RICOH head MH5420 with the primer composition set, the discharge temperature was adjusted so that the drive frequency was 10 kHz and the discharge speed was 7 m/sec, and after confirming that the primer composition was discharged normally from all nozzles, the shaking etc. The RICOH head MH5420 was allowed to stand for 10 minutes while maintaining negative pressure and discharge temperature without any intentional driving, and then the discharge performance of the primer composition was evaluated based on the following criteria.
Evaluation criteria ◎: Normal ejection from the first shot ○: Normal ejection within 3 shots △: Normal ejection within 10 shots ×: No normal ejection within 10 shots

"(A-1)/Polymerizable compound" in the table indicates the amount (% by mass) of the monofunctional polymerizable compound having an alicyclic hydrocarbon group in the polymerizable compound.
“(A-2)/Polymerizable compound” indicates the amount (% by mass) of the monomer represented by structural formula (1) in the polymerizable compound.
"Monofunctional polymerizable compound/polymerizable compound" indicates the amount (mass%) of the monofunctional polymerizable compound in the polymerizable compound.
"(A-1)/C" indicates the ratio of the amount (% by mass) of component (A-1) in the primer composition to the amount (% by mass) of component (C) in the primer composition.
“(A-1) other than IBXA” indicates the amount (mass%) of the monofunctional polymerizable compound having an alicyclic hydrocarbon group (excluding isobornyl acrylate) in the polymerizable compound.
"(A-1)+(A-2)/composition" refers to the sum of the monofunctional polymerizable compound having an alicyclic hydrocarbon group and the monomer represented by structural formula (1) in the primer composition. The amount (mass%) is shown.

Claims (8)

(A) A monofunctional polymerizable compound, (B) a photopolymerization initiator, and (C) a chlorinated polyolefin resin. A monofunctional polymerizable compound having a cyclic hydrocarbon group, and (A-2) structural formula (1)

(Here, R ¹ is a hydrogen atom or a methyl group, R ² is an alkylene group having 1 or more carbon atoms, n1 is an integer of 1 or more, and n2 is 0 or an integer of 1 or more. The amount (% by mass) of component (A-1) and component (C) contained in the composition is as follows (Formula 1):
Amount of component (A-1)/amount of component (C) ≧2.0 (Formula 1)
satisfying the following relationship, the amount of the monofunctional polymerizable compound (A) in the polymerizable compound contained in the composition is within the range of 70% by mass to 100% by mass, and the amount of the component (A- A composition characterized in that the amount of 1) is 25% by mass or more. The composition according to claim 1, wherein at least 30% by mass or more of component (A-1) is a monofunctional polymerizable compound having an alicyclic hydrocarbon group selected from those other than isobornyl acrylate. thing. The composition according to claim 1 or 2, characterized in that the amount of component (A-2) in the polymerizable compound is 5 to 50% by mass. The composition according to any one of claims 1 to 3, characterized in that the total amount of component (A-1) and component (A-2) is 50% by mass or more of the total amount of the composition. The composition according to any one of claims 1 to 4, wherein component (A-1) comprises at least t-butylcyclohexyl acrylate or trimethylcyclohexyl acrylate. The composition according to any one of claims 1 to 5, wherein component (A-2) comprises any one of ethoxydiethylene glycol acrylate, methoxydipropylene glycol acrylate, 2-ethylhexyldiethylene glycol acrylate, and methoxytripropylene glycol acrylate. thing. A printing method comprising printing the composition according to any one of claims 1 to 6 as a primer ink, photocuring it, and then printing a color ink and/or a clear ink. 8. The printing method according to claim 7, wherein the printed color ink and/or clear ink covers 90% or more of the surface of the photocured composition layer.