Method for manufacturing ink and printed matter

Abstract

The problem to be solved by the present invention is to provide an ink capable of forming a coating film that has high hardness, excellent chemical resistance, and excellent adhesion to a recording medium. [Solution] The inventors have solved the above problem by providing an ink that is cured by light emitted from an LED, comprising a compound (A) having two or more polymerizable unsaturated double bonds and a compound (B) having one polymerizable unsaturated double bond, wherein the compound (A) comprises a compound (a1) having a structure represented by the following general formula (1), the compound (B) is a compound (b1) having a heterocyclic structure, and the compound (A) accounts for 60 mass% or more of the total amount of the ink.

Description

Technical Field

[0001] The present invention relates to an ink that can be used in the production of various printed materials.

Background Art

[0002] Since active energy ray curable inks are excellent in curability and drying properties compared to other inks, they are used for printing on various recording media.

[0003] As the active energy ray curable ink, for example, an ink composition containing a colorant, a radical polymerization initiator having a specific structure, and a radical polymerizable compound such as tetrahydrofurfuryl acrylate is known (see, for example, Patent Document 1).

[0004] Printed materials obtained using the active energy ray curable ink are being considered for use in a wide range of applications. For example, when the printed material is used as a signboard or the like, the ink is required to be able to form a coating film with high hardness and excellent chemical resistance at a level that is not easily scratched and does not easily cause deterioration of the printed image even when chemicals or the like adhere to it.

[0005] However, when attempting to increase the hardness of the coating film, generally, the adhesion between the coating film and the recording medium decreases, and peeling of the coating film or the like may occur over time.

[0006] Thus, while there is a trade-off relationship between the high hardness and chemical resistance of the coating film and the adhesion to the recording medium, in fact, an ink capable of forming a coating film that achieves both has not yet been found.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Summary of the Invention

[0008] The problem to be solved by the present invention is to provide an ink capable of forming a coating film having high hardness, excellent chemical resistance, and excellent adhesion to a recording medium. [Means for Solving the Problems]

[0009] The present inventors have found an ink that is cured by light emitted from an LED and contains a compound (A) having two or more polymerizable unsaturated double bonds and a compound (B) having one polymerizable unsaturated double bond. The compound (A) contains a compound (a1) having a structure represented by the following general formula (1), the compound (B) is a compound (b1) having a heterocyclic structure, and the compound (A) is contained in an amount of 60% by mass or more based on the total amount of the ink, thereby solving the above problems.

[0010] [Chemical Formula]

[0011] (In general formula (1), R represents an alkylene group having 4 or more carbon atoms, and X represents a hydrogen atom or a methyl group.) [Effects of the Invention]

[0012] The ink of the present invention can form a coating film having high hardness, excellent chemical resistance, and excellent adhesion to a recording medium. [Modes for Carrying Out the Invention]

[0013] The ink of the present invention is an ink that is cured by light emitted from an LED, and contains a compound (A) having two or more polymerizable unsaturated double bonds and a compound (B) having one polymerizable unsaturated double bond. The compound (A) contains a compound (a1) having a structure represented by the following general formula (1), the compound (B) contains a compound (b1) having a heterocyclic structure, and the compound (A) is contained in an amount of 60% by mass or more based on the total amount of the ink. With the ink of the present invention, a coating film having high hardness, excellent chemical resistance, and excellent adhesion to a recording medium can be formed.

[0014]

Chemical formula

[0015] (In general formula (1), R represents an alkylene group having 4 or more carbon atoms, and X represents a hydrogen atom or a methyl group.)

[0016] The ink of the present invention is cured by light emitted from an LED (light emitting diode). Examples of the light include ultraviolet rays having a peak emission wavelength in the wavelength range of 350 nm to 420 nm, and it is particularly preferable to use ultraviolet rays having a peak emission wavelength in the region of 360 to 400 nm.

[0017] As the compound (A) contained in the ink of the present invention, those having two or more polymerizable unsaturated double bonds are used.

[0018] As the compound (A), preferably a compound having two or more, more preferably three or more polymerizable unsaturated double bonds is used. Since the crosslinking density of the cured coating film formed using the ink of the present invention becomes high, it is possible to form a cured coating film having excellent chemical resistance and high hardness. On the other hand, from the viewpoint of achieving both good chemical resistance, high hardness, and adhesion to the recording medium, the number of polymerizable unsaturated double bonds in the compound (A) is preferably 2 to 6, more preferably 2 to 3.

[0019] Further, the compound (A) is used in an amount of 60% by mass or more based on the total amount of the ink of the present invention. Thereby, since the crosslinking density of the cured coating film formed using the ink of the present invention becomes high, it is possible to form a cured coating film having excellent chemical resistance and high hardness. Here, when the content of the compound (A) is less than 60% by mass based on the total amount of the ink, it may cause a decrease in chemical resistance and hardness.

[0020] The compound (A) is preferably used in the range of 65% by mass to 85% by mass based on the total amount of the ink, and more preferably used in the range of 70% by mass to 80% by mass in order to obtain an ink capable of forming a cured coating film having more excellent chemical resistance and high hardness.

[0021] As the compound (A), those containing a compound (a1) having a structure represented by the general formula (1) are used.

[0022] [Chemical formula]

[0023] (In the general formula (1), R represents an alkylene group having 4 or more carbon atoms, and X represents a hydrogen atom or a methyl group.)

[0024] As the compound (a1), those in which R in the general formula (1) is an alkylene group having 4 to 9 carbon atoms are preferably used, those in which R is an alkylene group having 6 to 9 carbon atoms are preferably used, and those in which R is an alkylene group having 6 carbon atoms are particularly preferably used in order to obtain an ink capable of forming a coating film having high hardness, excellent chemical resistance, excellent adhesion to the recording medium, high sensitivity to light emitted from an LED, and quickly curing upon irradiation.

[0025] Specific examples of the compound (a1) include 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate, 1,5-pentanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate, 1,8-octanediol di(meth)acrylate, and 1,9-nonanediol di(meth)acrylate. Among them, the use of 1,6-hexanediol di(meth)acrylate is particularly preferable for obtaining an ink that can form a coating film with high hardness, excellent chemical resistance, excellent adhesion to the recording medium, high sensitivity to light emitted from an LED, and rapid curing upon irradiation.

[0026] The compound (a1) is preferably used in an amount of 20% by mass to 70% by mass, and particularly preferably in the range of 30% by mass to 60% by mass, based on the total amount of the ink, in order to obtain an ink that can form a coating film with excellent adhesion to the recording medium, high sensitivity to active energy rays, and rapid curing upon irradiation.

[0027] In addition, as the compound (A), a compound (a2) other than the compound (a1) can be used in combination with the compound (a1).

[0028] Examples of the compound (a2) include dicyclodecane dimethanol di(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate and other di(meth)acrylates, dicyclohexanedimethanol di(meth)acrylate, neopentyl glycol di(meth)acrylate, bisphenol A di(meth)acrylate, bisphenol F di(meth)acrylate, hydrogenated bisphenol A di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, poly(meth)acrylate of dipentaerythritol, and alkylene oxide modified products and caprolactone modified products thereof such as ethylene oxide and propylene oxide, ethylene oxide modified phosphoric acid (meth)acrylate, ethylene oxide modified alkyl phosphoric acid (meth)acrylate, etc., 2-(2-vinyloxyethoxy)ethyl (meth)acrylate, ethylene glycol divinyl ether, diethylene glycol divinyl ether, triethylene glycol divinyl ether, propylene glycol divinyl ether, dipropylene glycol divinyl ether, butanediol divinyl ether, hexanediol divinyl ether, cyclohexanedimethanol divinyl ether, trimethylolpropane trivinyl ether and other di- or trivinyl ether compounds, urethane (meth)acrylate, epoxy (meth)acrylate, polyester (meth)acrylate, etc. These can be used alone or in combination of two or more kinds. As the compound (a2), it is preferably used in the range of 60% by mass to 95% by mass, and more preferably in the range of 75% by mass to 90% by mass, based on the total amount of the ink, for achieving both good adhesion to the substrate and chemical resistance.

[0029] Next, the compound (B) having one polymerizable unsaturated double bond will be described.

[0030] As the compound (B), a compound (b1) having a heterocyclic structure having one polymerizable unsaturated double bond is used alone, or the compound (b1) and a compound (b2) having one polymerizable unsaturated double bond other than the compound (b1) are used in combination. By using the compound (B), the crosslinking density formed using only the compound (A) having two or more polymerizable unsaturated double bonds is appropriately reduced as compared with the case of using only the compound (A). As a result, it is possible to obtain an ink capable of forming a cured coating film having good flexibility without significantly impairing the hardness, chemical resistance, adhesion, and sensitivity to light emitted from the LED of the coating film. Examples of the polymerizable unsaturated double bond of the compound (B) include a (meth)acryloyl group, and an acryloyl group is preferable.

[0031] As the compound (B), it is preferably used in the range of 1 to 39% by mass, more preferably in the range of 5% to 30% by mass, and particularly preferably in the range of 10% to 20% by mass with respect to the total amount of the ink. This is particularly preferable for obtaining an ink capable of forming a cured coating film having good flexibility, adhesion to the recording medium, high hardness of the cured coating film, excellent chemical resistance, and sensitivity without significantly impairing these properties.

[0032] As the compound (b1) having a heterocyclic structure, for example, a compound having a caprolactone structure, a compound having a pyridine structure, a compound having a pyrrolidone structure, a compound having a tetrahydrofuran structure, or a compound having a cyclic trimethylolpropane structure can be used. Among them, as the compound (b1), a compound having a caprolactone structure is preferably used. Specifically, the use of N-vinylcaprolactam is particularly preferable for obtaining an ink capable of forming a cured coating film having good flexibility, adhesion to the recording medium, high hardness of the cured coating film, excellent chemical resistance, and higher sensitivity without significantly impairing these properties.

[0033] In addition, the compound (b1) having a heterocyclic structure including the compound having a caprolactone structure is preferably used in an amount of 15% by mass or less, more preferably in the range of 1% to 12% by mass, and most preferably in the range of 5% to 10% by mass, based on the total amount of the ink. This can form a cured coating film with good flexibility and adhesion to the recording medium without significantly impairing the high hardness and excellent chemical resistance of the cured coating film, and is particularly preferable for obtaining an ink with even higher sensitivity.

[0034] As the compound (b2), known monofunctional compounds can be used without particular limitation. Examples include acrylates having substituents such as methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, amyl acrylate, 2-ethylhexyl acrylate, isooctyl acrylate, nonyl acrylate, isodecyl acrylate, dodecyl acrylate, hexadecyl acrylate, octadecyl acrylate, cyclohexyl acrylate, benzyl acrylate, methoxyethyl acrylate, butoxyethyl acrylate, phenoxyethyl acrylate, nonylphenoxyethyl acrylate, glycidyl acrylate, dimethylaminoethyl acrylate, diethylaminoethyl acrylate, isobornyl acrylate, dicyclopentanyl acrylate, dicyclopentenyl acrylate, and dicyclopentenyloxyethyl acrylate. As the compound (b2), it is preferably used in an amount of 5% to 40% by mass, more preferably in the range of 10% to 25% by mass, based on the total amount of the ink. This is more preferable for achieving both excellent adhesion to the recording medium and excellent chemical resistance.

[0035] As the ink of the present invention, it is preferable to use a combination containing the compound (A), the compound (B), and further a compound (C) having one or more methacryloyl groups different from the compound (A) and the compound (B) in order to further improve the adhesion to the recording medium.

[0036] Examples of the compound (C) include monofunctional methacrylates such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, amyl methacrylate, 2-ethylhexyl methacrylate, isooctyl methacrylate, nonyl methacrylate, lauryl methacrylate, tridecyl methacrylate, dodecyl methacrylate, hexadecyl methacrylate, octadecyl methacrylate, isodecyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, methoxyethyl methacrylate, butoxyethyl methacrylate, phenoxyethyl methacrylate, nonylphenoxyethyl methacrylate, glycidyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, isobornyl methacrylate, tetrahydrofurfuryl methacrylate, dicyclopentanyl methacrylate, dicyclopentenyl methacrylate, dicyclopentenyloxyethyl methacrylate; 1,3-butylene glycol dimethacrylate, 1,4-butanediol dimethacrylate, 1,5-pentanediol dimethacrylate, 3-methyl-1,5-pentanediol dimethacrylate, 1,6-hexanediol dimethacrylate, neopentyl glycol dimethacrylate, 1,8-octanediol dimethacrylate, 1,9-Nonanediol dimethacrylate, tricyclodecane dimethanol dimethacrylate, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, propylene glycol dimethacrylate, dipropylene glycol dimethacrylate, tripropylene glycol dimethacrylate, polypropylene glycol dimethacrylate, dimethacrylate of tris(2-hydroxyethyl) isocyanurate, dimethacrylate of diol obtained by adding 4 moles or more of ethylene oxide (EO) or propylene oxide (PO) to 1 mole of neopentyl glycol, dimethacrylate of diol obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mole of bisphenol A, dimethacrylate of triol obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane, trimethacrylate of triol obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane, dimethacrylate of diol obtained by adding 4 moles or more of ethylene oxide or propylene oxide to 1 mole of bisphenol A, trimethylolpropane trimethacrylate, pentaerythritol trimethacrylate, polymethacrylate of dipentaerythritol, ethylene oxide-modified methacrylate phosphate, ethylene oxide-modified alkyl methacrylate phosphate, etc. can be used. As the compound (C), among those described above, it is preferable to use trimethacrylate of triol obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of trimethylolpropane or neopentyl glycol dimethacrylate.

[0037] As the compound (C), it is preferably in the range of 0.1% by mass to 10% by mass, and more preferably in the range of 0.5% by mass to 5% by mass with respect to the total amount of the ink of the present invention, in order to further improve the adhesion to the recording medium.

[0038] The ink of the present invention cures by receiving light emitted from an LED. As the ink of the present invention, those containing a photoinitiator can be used.

[0039] Examples of the photoinitiator include benzoin isobutyl ether, 2,4 - diethylthioxanthone, 2 - isopropylthioxanthone, benzyl, 2,4,6 - trimethylbenzoyldiphenylphosphine oxide 6 - trimethylbenzoyldiphenylphosphine oxide, 2 - benzyl - 2 - dimethylamino - 1 - (4 - morpholinophenyl) - butan - 1 - one, bis(2,6 - dimethoxybenzoyl) - 2,4,4 - trimethylpentylphosphine oxide, 1 - hydroxycyclohexyl phenyl ketone, benzoin ethyl ether, benzyl dimethyl ketal, 2 - hydroxy - 2 - methyl - 1 - phenylpropan - 1 - one, 1 - (4 - isopropylphenyl) - 2 - hydroxy - 2 - methylpropan - 1 - one, and 2 - methyl - 1 - (4 - methylthiophenyl) - 2 - morpholinopropan - 1 - one, benzophenone, 4 - phenylbenzophenone, isophthalophenone, 4 - benzoyl - 4'-methyl - diphenyl sulfide, etc. can be used.

[0040] Among the above - mentioned photoinitiators, it is preferable to use acylphosphine oxide - based photoinitiators.

[0041] Also, when using a UV - LED light source as the photoinitiator, 2 - benzyl - 2 - dimethylamino - 1 - (4 - morpholinophenyl) - butan - 1 - one, 2 - (dimethylamino) - 2 - [(4 - methylphenyl)methyl] - 1 - (4 - morpholinophenyl) - butan - 1 - one), bis(2,4,6 - trimethylbenzoyl)phenylphosphine oxide, 2,4,6 - trimethylbenzoyl - diphenyl - phosphine oxide, ethyl phenyl(2,4,6 - trimethylbenzoyl)phosphinate, 2,4 - diethylthioxanthone, 2 - isopropylthioxanthone, etc., corresponding to the wavelength of the light emitted from the UV - LED light source, are preferably used.

[0042] It is preferable to use the photoinitiator in combination with a sensitizer. As the sensitizer, for example, trimethylamine, methyldiethanolamine, triethanolamine, p - diethylaminoacetophenone, ethyl p - dimethylaminobenzoate, isoamyl p - dimethylaminobenzoate, N,N - dimethylbenzylamine, 4,4’ - bis(diethylamino)benzophenone, etc. can be used.

[0043] As the ink of the present invention, those containing a colorant as required can be used.

[0044] As the colorant, for example, pigments or dyes can be used. As the pigment, for example, phthalocyanine pigments used in cyan ink, quinacridone - based pigments used in magenta ink, azo pigments used in yellow ink, carbon black used in black ink, white pigments that can be used in white ink, etc. can be mentioned.

[0045] As the phthalocyanine pigment used in the cyan ink, for example, C.I. Pigment Blue 1, 2, 3, 15:3, 15:4, 16:6, 16, 17:1, 75, 79, etc. can be mentioned.

[0046] As the quinacridone - based pigment used in magenta ink, for example, C.I. Pigment Red 122, C.I. Pigment Red 202, C.I. Pigment Red 209, C.I. Pigment Violet 19, etc. can be mentioned.

[0047] As the azo pigment used in yellow ink, for example, C.I. Pigment Yellow 120, 151, 154, 175, 180, 181, 1, 65, 73, 74, 116, 12, 13, 17, 81, 83, 150, 155, 214, 128, etc., including monoazo and disazo pigments, are included.

[0048] Examples of carbon black used in black ink include No. 2300, No. 900, MCF88, No. 33, No. 40, No. 45, No. 52, MA7, MA8, MA100, No. 2200B, etc. of Mitsubishi Chemical Corporation; Raven5750, 5250, 5000, 3500, 1255, 700, etc. of Columbian Chemicals Company; Regal400R, 330R, 660R, Mogul L, 700, Monarch800, 880, 900, 1000, 1100, 1300, 1400, etc. of Cabot Corporation; Color Black FW1, FW2, FW2V, FW18, FW200, ColorBlack S150, S160, S170, Printex 35, U, V, 140U, Special Black 6, 5, 4A, 4, etc. of Degussa AG.

[0049] There is no particular limitation on the white pigment that can be used in white ink, and known inorganic white pigments can be used. Examples of the inorganic white pigment include sulfates or carbonates of alkaline earth metals, silicas such as fine silica and synthetic silicates, calcium silicate, alumina, alumina hydrate, titanium oxide, zinc oxide, talc, clay, etc. As the inorganic white pigment, those in which the surface such as the above-mentioned silicas is surface-treated by various surface treatment methods can also be used.

[0050] The average particle size (median diameter: 50% diameter) of the pigment is preferably in the range of 10 nm to 300 nm, more preferably 50 nm to 200 nm.

[0051] Among the pigments, the white pigment is used in white ink for imparting hiding power to printed matter. In order to obtain white ink having excellent hiding power, excellent discharge stability, and high color development of printed images, it is preferable to use those having an average particle size (median diameter: 50% diameter) of 100 nm to 500 nm, and more preferably 150 nm to 400 nm.

[0052] The pigment is preferably contained in the range of 1% by mass to 20% by mass, more preferably in the range of 1% by mass to 10% by mass, and most preferably in the range of 1% by mass to 5% by mass, based on the total amount of the ink, in order to obtain sufficient image density and light resistance of the printed image.

[0053] The pigment may be used in combination with a pigment dispersant, a pigment derivative (synergist), etc. in order to obtain good dispersion stability in the compound (A) and the compound (B).

[0054] The pigment dispersant is not particularly limited. For example, Ajisper PB821, PB822, PB817 manufactured by Ajinomoto Fine-Techno Co., Ltd., Solsperse 24000GR, 32000, 33000, 39000 manufactured by Avecia, Inc., Disparon DA-703-50, DA-705, DA-725 manufactured by Nippon Kayaku Co., Ltd., etc. can be used.

[0055] The pigment dispersant is preferably used in the range of 10% by mass to 100% by mass with respect to the pigment, and more preferably, one in the range of 20% by mass to 80% by mass is used in order to obtain an ink having more excellent ejection stability and pigment dispersibility.

[0056] As the ink of the present invention, in addition to the above-described components, those containing a polymerization inhibitor such as hydroquinone, methoxyquinone, di-t-butylhydroquinone, P-methoxyphenol, butylhydroxytoluene, nitrosoamine salt, etc. can be used as needed. The polymerization inhibitor can be used in the range of 0.01% by mass to 2% by mass with respect to the total amount of the ink of the present invention.

[0057] As the ink of the present invention, those containing a non-reactive resin such as an acrylic resin, an epoxy resin, a terpene phenol resin, a rosin ester, etc. can be used in order to further improve the adhesion to a recording medium such as a plastic substrate.

[0058] When the ink of the present invention is ejected by an inkjet recording method, the viscosity of the ink at 25°C is preferably in the range of 3 mPa·sec to 30 mPa·sec, and more preferably in the range of 5 mPa·sec to 20 mPa·sec in order to ensure good ejection stability from the ink ejection nozzles.

[0059] The ink of the present invention can be produced, for example, by mixing the compound (A), the compound (B), and, if necessary, the compound (C), a pigment, a pigment dispersant, a resin, etc. using an ordinary disperser such as a bead mill, then adding a photopolymerization initiator, and adding and mixing additives such as a polymerization inhibitor, a sensitizer, and a surface tension modifier if necessary.

[0060] The ink can also be produced by previously producing a high-concentration pigment dispersion (mill base) containing a pigment, a pigment dispersant, a resin, etc. using an ordinary disperser such as a bead mill, and then mixing and stirring a photopolymerization initiator, the compound (A), the compound (B), the compound (C), additives, etc. into the pigment dispersion.

[0061] As the disperser, in addition to a bead mill, various known and commonly used dispersers such as an ultrasonic homogenizer, a high-pressure homogenizer, a paint shaker, a ball mill, a roll mill, a sand mill, a sand grinder, a dyno mill, a dispersermat, an SC mill, and a nanomizer can be used.

[0062] The ink of the present invention cures by irradiation with light emitted from an LED, preferably light such as ultraviolet light. As a light source such as ultraviolet light, a UV-LED lamp or the like can be used.

[0063] The ink of the present invention can be preferably used exclusively for printing by an inkjet recording method using an inkjet recording apparatus.

[0064] As the inkjet recording method, any conventionally known method can be used. For example, a method of ejecting droplets by utilizing the vibration of a piezoelectric element (a recording method using an inkjet head that forms ink droplets by mechanical deformation of an electrostrictive element) and a method of utilizing thermal energy can be mentioned.

[0065] The ink can be ejected using an inkjet recording apparatus, printed on a recording medium, and cured by irradiating light emitted from an LED, thereby manufacturing a printed matter. Examples of the printed matter include advertisements, signboards, guide boards, promotional item printing, and the like.

[0066] Since the ink of the present invention is excellent in adhesion to various types of recording media, it can be easily printed on the surface of a recording medium having a curved surface or an irregular shape with unevenness.

[0067] As the recording medium, for example, a plastic substrate can be used. Specifically, as the plastic substrate, ABS (acrylonitrile-butadiene-styrene) resin, PVC (polyvinyl chloride) / ABS resin, PA (polyamide) / ABS resin, PC (polycarbonate) / ABS resin, PBT (polybutylene terephthalate) / ABS and other ABS-based polymer alloys, AAS (acrylonitrile-acrylic rubber-styrene) resin, AS (acrylonitrile-styrene) resin, AES (acrylonitrile-ethylene rubber-styrene) resin, MS ((meth)acrylate-styrene) - based resin, PC (polycarbonate) - based resin, acrylic resin, methacrylic resin, PP (polypropylene) - based resin, and other substrates can be mentioned. These are general-purpose plastics used for injection molding.

[0068] In addition, as the plastic substrate, for example, a thermoplastic resin film used for packaging materials can also be used.

[0069] Examples of the thermoplastic resin film include those generally used for food packaging, such as polyethylene terephthalate (PET) film, polystyrene film, polyamide film, polyacrylonitrile film, polyethylene film (LLDPE: low-density polyethylene film, HDPE: high-density polyethylene film), and polyolefin films such as polypropylene film (CPP: uniaxially oriented polypropylene film, OPP: biaxially oriented polypropylene film), polyvinyl alcohol film, ethylene-vinyl alcohol copolymer film, etc. As the thermoplastic resin film, those subjected to stretching treatments such as uniaxial stretching or biaxial stretching, or those with flame treatment or corona discharge treatment applied to the surface can also be used.

Examples

[0070] Hereinafter, the present invention will be described in more detail with reference to examples.

[0071] [Preparation Example of Pigment Dispersion] Preparation Example 1; Cyan Pigment Dispersion (1) 10 parts by mass of Fastogen Blue TGR-G (phthalocyanine pigment C.I. Pigment Blue 15:4 manufactured by DIC Corporation), 4.5 parts by mass of Solsperse 32000 (a polymeric pigment dispersant manufactured by Lubrizol), and 85.5 parts by mass of MIRAMER M222 (dipropylene glycol diacrylate manufactured by MIWON) were stirred and mixed with a stirrer for 1 hour, and then treated with a bead mill for 2 hours to obtain cyan pigment dispersion (1).

[0072] Preparation Example 2; Cyan Pigment Dispersion (2) Cyan pigment dispersion (2) was obtained in the same manner as in Preparation Example 1, except that 85.5 parts by mass of MIRAMER M200 (1,6-hexanediol diacrylate manufactured by MIWON) was used instead of 85.5 parts by mass of MIRAMER M222.

[0073] Preparation Example 3; Magenta Pigment Dispersion (3) Instead of 10 parts by mass of Fastogen Blue TGR-G (phthalocyanine pigment C.I. Pigment Blue 15:4, manufactured by DIC Corporation), 10 parts by mass of Fastogen Super Magenta RTS (magenta pigment C.I. Pigment Red 122, manufactured by DIC Corporation) was used, and a magenta pigment dispersion (3) was obtained in the same manner as in Preparation Example 1.

[0074] Preparation Example 4; Yellow Pigment Dispersion (4) 10 parts by mass of Levascreen Yellow G01 (C.I. Pigment Yellow 150, manufactured by Ranses Co., Ltd.), 6 parts by mass of Solsperse 32000 (polymeric pigment dispersant, manufactured by Lubrizol), and 84 parts by mass of MIRAMER M222 (dipropylene glycol diacrylate, manufactured by MIWON) were stirred and mixed with a stirrer for 1 hour, and then treated with a bead mill for 2 hours to obtain a yellow pigment dispersion (4).

[0075] Preparation Example 5; Black Pigment Dispersion (5) 10 parts by mass of Carbon Black #960 (carbon black, manufactured by Mitsubishi Chemical Corporation), 4.5 parts by mass of Solsperse 32000 (polymeric pigment dispersant, manufactured by Lubrizol), and 85.5 parts by mass of MIRAMER M222 (dipropylene glycol diacrylate, manufactured by MIWON) were stirred and mixed with a stirrer for 1 hour, and then treated with a bead mill for 2 hours to obtain a black pigment dispersion (5).

[0076] Preparation Example 6; White Pigment Dispersion (6) 50 parts by mass of TITANIX JR-806 (titanium oxide, manufactured by Teika Corporation), 2.5 parts by mass of Solsperse 24000 (polymeric pigment dispersant, manufactured by Lubrizol), and 47.5 parts by mass of MIRAMER M222 (dipropylene glycol diacrylate, manufactured by MIWON) were stirred and mixed with a stirrer for 1 hour, and then treated with a bead mill for 2 hours to obtain a white pigment dispersion (6).

[0077] Example 1 Put 9 parts by mass of MIRAMER M3130, 56 parts by mass of MIRAMER M200, 9 parts by mass of V-CAP, and 0.2 parts by mass of KF-351A into a container, stir and mix them, then add 3.5 parts by mass of Omnirad819, 4 parts by mass of Omnirad TPO-H, and 2.5 parts by mass of Kayacure DETX-S, and mix at a temperature of 60 °C for 30 minutes.

[0078] Next, the mixture and the pigment dispersion (1) were mixed and stirred for 10 minutes to obtain an ink having the formulation shown in Table 1.

[0079] Examples 2 to 12 and Comparative Examples 1 to 4 Inks were produced in the same manner as in Example 1, except that the formulations of the inks were changed to those described in Tables 1 to 3.

[0080] The details of the raw materials used are described below. () are the abbreviations described in the table. · MIRAMER M3130 (M3130): Ethylene oxide (EO) modified trimethylolpropane triacrylate manufactured by MIWON · MIRAMER M222 (M222): Dipropylene glycol diacrylate manufactured by MIWON · MIRAMER M200 (M200): 1,6 - Hexanediol diacrylate manufactured by MIWON · MIRAMER M213 (M213): Neopentyl glycol dimethacrylate manufactured by MIWON · V-CAP (V-CAP): N-Vinyl-2-caprolactam manufactured by Ashland · Light Acrylate POA (POA): Phenoxyethyl acrylate manufactured by Kyoeisha Chemical Co., Ltd. · KF-351A (KF-351A): Polysiloxane manufactured by Shin-Etsu Chemical Co., Ltd. · Omnirad819 (819): Bis(2,4,6-trimethylbenzoyl)-phenylphosphine oxide manufactured by IGM · Omnirad TPO-H (TPO): 2,4,6-Trimethylbenzoyl-diphenyl-phosphine oxide manufactured by IGM ·Kayacure DETX-S (DETX): Diethylthioxanthone manufactured by Nippon Kayaku Co., Ltd.

[0081] [Static surface tension] The static surface tension was measured using a Wilhelmy type surface tension measuring instrument: DY-300 manufactured by Kyowa Interface Science Co., Ltd. after immersing the ink placed in a plastic container in a constant temperature water bath and adjusting it to 25°C.

[0082] [Viscosity] The viscosity of the ink at 25°C was measured using a viscometer: TV-25 manufactured by Toki Sangyo Co., Ltd. The measurement rotation speed of the said measuring device was set to 20 rpm / min.

[0083] [Curability] The ink was applied to a polycarbonate plate (PC: manufactured by Asahi Glass Co., Ltd., Lexan, thickness 1 mm) using a spin coater to a thickness of 6 μm. Next, an LED irradiation device manufactured by Hamamatsu Photonics K.K. (emission wavelength: 385 nm, peak intensity: 500 mW / cm 2 ) was used to irradiate such that the energy amount per irradiation was 30 J / m 2 , and the integrated value of the energy amount of irradiation until it became tack-free when touching the said coated surface was measured.

[0084] The ink capable of forming a coating film with the integrated value of the irradiation energy amount being 400 mJ / cm 2 or less was evaluated as having excellent curability.

[0085] [Adhesion] The said ink was applied to a polycarbonate plate (PC: manufactured by Asahi Glass Co., Ltd., Lexan, thickness 1 mm), an acrylic plate (PMMA: manufactured by Kuraray Co., Ltd., Komoglas), and a vinyl chloride plate (PVC: manufactured by Mitsubishi Chemical Corporation, Hisiprate GE301) to a thickness of 10 μm using a spin coater. Next, an LED irradiation device manufactured by Hamamatsu Photonics K.K. (emission wavelength: 385 nm, peak intensity: 500 mW / cm 2 , and the energy amount per irradiation being 30 J / m 2Using [the irradiation device], irradiation was carried out until the coating surface became tack-free to obtain a cured coating film.

[0086] After making cuts with a cutter knife in a 5×5 grid pattern with a 2-mm interval on the obtained cured coating film, a cellophane adhesive tape manufactured by Nichiban Co., Ltd. was attached to the cured coating film, and the surface of the tape was rubbed 10 times with a fingernail. Next, the tape was vigorously peeled off at a peeling speed of approximately 1 cm / sec, and the number of grid cells of the coating film remaining on the surfaces of the polycarbonate plate, vinyl chloride plate, and acrylic plate was confirmed.

[0087] Evaluation Criteria Good: The number of coating film cells is 20 or more Fair: The number of coating film cells is 15 or more and less than 20 Poor: The number of coating film cells is less than 15

[0088] [Chemical Resistance] The ink was applied to a polycarbonate plate (Lexan, thickness 1 mm, PC, manufactured by Asahi Glass Co., Ltd.) with a spin coater to a thickness of 10 μm. Next, an LED irradiation device manufactured by Hamamatsu Photonics K.K. (emission wavelength: 385 nm, peak intensity: 500 mW / cm 2 , and the energy amount per irradiation is 30 J / m 2 ) was used to irradiate until the coating surface became tack-free to obtain a cured coating film.

[0089] The obtained cured coating film was rubbed 10 times to the left and right with a cotton swab dipped in a mixture of ethanol and water (ethanol content ratio 70% by mass) over a width of approximately 2 cm. Those without rubbing marks on the coating film surface were evaluated as "○", and those with rubbing marks confirmed were evaluated as "×".

[0090] [Pencil Hardness] The ink was applied to a polycarbonate plate (Lexan, thickness 1 mm, PC, manufactured by Asahi Glass Co., Ltd.) with a spin coater to a thickness of 10 μm. Next, an LED irradiation device manufactured by Hamamatsu Photonics K.K. (emission wavelength: 385 nm, peak intensity: 500 mW / cm 2 , and the energy amount per irradiation is 30 J / m2 ) was used to irradiate until the coated surface became tack-free to obtain a cured coating film.

[0091] The pencil hardness of the obtained cured coating film was evaluated according to the test method of JIS-K5600-5-4 with respect to. A pencil made by MITSU-BISHI was used, and the test equipment was evaluated using a pencil scratch hardness tester manufactured by Toyo Seiki Seisakusho Co., Ltd.

[0092]

Table 1

[0093]

Table 2

[0094]

Table 3

Claims

1. An ink that cures by light emitted from an LED, comprising a compound (A) having two or more radically polymerizable unsaturated double bonds, a compound (B) having one radically polymerizable unsaturated double bond, and a compound (C) having one or more methacryloyl groups with a structure different from that of the compound (A) and the compound (B), wherein the compound (A) contains a compound (a1) having a structure represented by the following general formula (1), the compound (B) contains a compound (b1) having a heterocyclic structure, the compound (b1) is a compound having a caprolactone structure, the compound (C) is a compound selected from the group consisting of trimethacrylate of triol to which 3 moles or more of ethylene oxide or propylene oxide are added per 1 mole of trimethylolpropane and neopentyl glycol dimethacrylate, the compound (a1) is contained in an amount of 30% by mass to 60% by mass based on the total amount of the ink, and the compound (A) is contained in an amount of 60% by mass or more based on the total amount of the ink, the compound (b1) is contained in the range of 1% by mass to 12% by mass based on the total amount of the ink, and the compound (C) is contained in an amount of 0.5% by mass to 5% by mass based on the total amount of the ink. (In the general formula (1), R represents an alkylene group having 4 to 9 carbon atoms, and X represents a hydrogen atom or a methyl group.)

2. A method for producing a printed matter, characterized in that the ink according to claim 1 is printed on a recording medium, and the printed surface of the recording medium is irradiated with light emitted from an LED to be cured.

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