JP7069674B2 - Method for manufacturing UV-curable printed matter and UV-curable printed matter - Google Patents

Description

The present invention relates to an ultraviolet curable printed matter having a cured image of an ultraviolet curable composition by offset printing, and a method for producing an ultraviolet curable printed matter.

Ultraviolet curable offset inks that cure under ultraviolet conditions are widely used in the field of package printing for food and pharmaceutical packaging such as toys and paper containers because of the convenience of instant drying characteristics.

The UV irradiation system for UV offset printing is a system that saves power and suppresses the generation of ozone and heat, for example, an LED system that uses a UV-LED light source, and a hybrid UV that uses one metal halide lamp that cuts infrared rays and short wavelengths. The system is gradually shifting to an energy-saving UV system, etc., in which the number of conventional UV lamps has been reduced from the usual 3 to 4 to 1 lamp.
Dedicated high-sensitivity UV inks designed to support these new systems have tended to switch from general oil-based inks in recent years in commercial printing, and their handleability, printability, printed matter quality, etc. have tended to increase. In various respects, performance equivalent to that of general oil-based ink is required.

Among them, one of the performances that the ultraviolet curable offset ink is generally inferior to that of general oil-based ink is deinkability. For high-sensitivity UV inks, which are expected to become widespread in the future, it is desired to design inks in consideration of this deinking property.

At a paper manufacturing company, used printing paper is crushed under an alkaline aqueous solution in the deinking process, and then the stains are removed by the ink component in the process of floating the used printing paper in bubbles with a surfactant called flotation. At this time, if a large amount of black components called darts that could not be completely decomposed remain, the paper cannot be made blank when the paper is made again, and the recycling suitability tends to deteriorate.
The fact that the amount of this dirt is larger in the ultraviolet curable offset ink than in the general oil-based ink has the same tendency in the high-sensitivity UV ink.

On the other hand, in the field of inkjet, a method for producing deinked pulp (for example, Patent Document 1) and a method for producing deinked pulp (for example, Patent Document 2) have been proposed.
However, these are not intended for UV-curable offset inks that are difficult to deink, but UV-curable printed matter using high-sensitivity UV inks, which are expected to become widespread in the future, and UV-curable printed matter with excellent deinking suitability. It is desired to establish a method for producing printed matter.

Japanese Patent Application Laid-Open No. 2013-22109 JP 2011-080187

An object of the present invention is to provide an ultraviolet curable printed matter which is comparable in curability and film strength of a printing ink film and has excellent deinkability in a paper recycling process, and a method for producing the printed matter.

As a result of diligent research to solve the above problems, the present inventors have obtained a deinking treatment for an ultraviolet curable printed matter having a cured image of an ultraviolet curable composition by offset printing provided on a substrate. We have found an ultraviolet curable printed matter based on the number of dirts, which is a measure of the ease of deinking, and have completed the present invention.

That is, the present invention is an ultraviolet curable printed matter having a cured image of an ultraviolet curable composition provided on a substrate by offset printing, and the average particle size of the dart after deinking treatment is 250 μm or more. The present invention relates to an ultraviolet curable printed matter characterized in that the number is 70,000 pieces / m ² or less.

Further, the present invention relates to the ultraviolet curable printed matter according to claim 1, wherein the (meth) acrylate compound contained in the ultraviolet curable composition has a (meth) acryloyl group concentration of 2.0 to 7.0 mmol / g. ..

Furthermore, the present invention relates to an ultraviolet curable printed matter in which the ultraviolet curable composition contains at least one selected from the following (a) to (e) in an amount of 3.0 to 10.0% by mass based on the total amount of the composition.

(A) Adipate (b) Sebacic acid or sebacic acid ester (c) Fatty acid alcohol with a boiling point of 260 ° C or higher (d) Liquid polyethylene wax having a viscosity of 3000 cps or less at 25 ° C (e) White vaseline

Further, the present invention relates to an ultraviolet curable printed matter in which the ultraviolet curable composition contains a photopolymerization initiator (f) having a molar extinction coefficient of 2000 ml / g · cm or less in a wavelength region of 300 nm or more.

Further, the present invention is an ultraviolet curable printed matter in which the photopolymerization initiator (f) is 1-hydroxy-cyclohexyl-phenyl-ketone and / or 2-hydroxy-2-methyl-1-phenyl-propane-1-one. Regarding.

Further, the present invention is the method for producing an ultraviolet curable printed matter, wherein an image of an ultraviolet curable composition is formed on a substrate by offset printing (I) and a step (II) of irradiating ultraviolet rays. The present invention relates to a method for producing an ultraviolet curable printed matter, which comprises having them in this order.

The ultraviolet curable printed matter of the present invention can provide an ultraviolet curable printed matter which is comparable in curability and film strength of a printing ink film and has excellent deinking property in a paper recycling process, and a method for producing the printed matter.

The ultraviolet-curable printed matter of the present invention is an ultraviolet-curable printed matter having a cured image of an ultraviolet-curable composition by offset printing provided on a substrate, and has an average particle size of dart of 250 μm or more after deinking. It is essential that the number of certain dirt is 70,000 pieces / m ² or less.

As a general deinking process for recycling printed so-called used paper, the paper is finely crushed under an alkaline aqueous solution and then floated on bubbles with a surfactant called flotation to remove stains. Work to remove stains mainly caused by the ink components contained. At this time, if a large amount of undecomposed black component called dirt remains, it will affect the blanking of the paper when it is made again, so the amount of dirt is important as a measure of recycling suitability. be.

Next, it is preferable that the (meth) acryloyl group concentration of the (meth) acrylate compound contained in the ultraviolet-curable composition used in the ultraviolet-curable printed matter of the present invention is in the range of 2.0 to 7.0 mmol / g. .. This is due to the ultraviolet curable monomer called the (meth) acrylic monomer used in the ultraviolet curable composition. The ultraviolet curable monomer will be described later.
When the (meth) acryloyl group concentration is 2.0 or more, curability that does not cause any problem in actual work can be obtained even in a high-sensitivity UV system or a UV-LED system that is harder to cure than a conventional ultraviolet curable system. Further, when the concentration of the (meth) acryloyl group is 7.0 mmol / g or less, it is possible to prevent the degree of curing of the ultraviolet cured product from further progressing due to the change over time of the printed matter and conversely lowering the deinkability.
Above all, the (meth) acryloyl group concentration is preferably in the range of 2.0 to 4.0 mmol / g.
The range of 2.0 to 3.9 l / g is most preferable.

The UV-curable composition used in the UV-curable printed matter of the present invention preferably contains at least one selected from the following (a) to (e) in an amount of 3.0 to 10.0% by mass based on the total amount of the composition. .. Plasticity can be imparted to the composition by adding an appropriate amount of these (a) to (e), and the hardness of the cured ink layer is softened while maintaining sufficient curability as a printed matter, and the deinking step is performed. It is possible to accelerate the decomposition of the ink with an alkaline solution.
(A) to (e) may be used alone or in combination of two or more.
When the total amount of the additions (a) to (e) is 3.0% by mass or more of the total amount of the composition, the degree of curing of the ultraviolet cured product further progresses due to the change over time of the printed matter, and the deinking property is reversed. It can be suppressed that it is lowered. If the total amount of the additions (a) to (e) is 10.0% by mass or less of the total amount of the composition, it is difficult to cure in a high-sensitivity UV system or UV-LED system as compared with the conventional ultraviolet curing type system. However, curability can be obtained without any problem in actual work.

(A) Adipate (b) Sebacic acid or sebacic acid ester (c) Fatty acid alcohol with a boiling point of 260 ° C or higher (d) Liquid polyethylene wax having a viscosity of 3000 cps or less at 25 ° C (e) White vaseline

Specific examples of the (a) adipate ester include bis (2-ethylhexyl) diisononyl adipate (weight average molecular weight 371, boiling point 335 ° C., CAS number 103-23-1) and diisononyl adipate (weight average). Examples thereof include molecular weight 339, boiling point 227 ° C., CAS No. 33703-08-1), diisononyl adipate (weight average molecular weight 427, boiling point 244 ° C., CAS No. 27178-16-1), and diisononyl adipate is preferable. Further, these may be used alone or in combination of two or more.

Examples of the (b) sebacic acid (di) ester include sebacic acid, sebacic acid diester, sebacic acid monoester and the like. Among them, sebacic acid (di) ester is preferable, and specifically, sebacic acid dioctyl (weight average molecular weight). 426.7, boiling point 256 ° C., CAS number 122-62-3) are preferred. Further, these may be used alone or in combination of two or more.

Generally, the ultraviolet curable composition by offset printing does not contain a VOC component having a boiling point of 260 ° C. or lower.
The fatty acid alcohol having a boiling point of 260 ° C. or higher in (c) is a higher alcohol that does not correspond to the VOC component, and specifically, lauryl alcohol (boiling point 264 ° C., CAS number: 112-53-8), myristyl alcohol ( 1-Tetradecanol, boiling point 260 ° C., CAS number: 112-72-1), stearyl alcohol (1-octadecanol, boiling point 350 ° C., CAS number: 112-92-5), isostearyl alcohol (16-methyl) Heptadecene-1-ol, boiling point 270.5 ° C., CAS number: 27458-93-1), arachidyl alcohol (1-eicosanol, boiling point 372 ° C., CAS number: 629-96-9), 2-decyl-1 -Tetradecanol (boiling point 271-275 ° C., CAS number: 58670-89-6), rac-R-3-[(Z) -9-octededecenyloxy] -1,2-propanediol (R is Examples thereof include 1 to 10 carbon atoms, a boiling point of 470.6 ° C., CAS34783-94-3), and among them, stearyl alcohol (1-octadecanol) is preferable.
Further, these may be used alone or in combination of two or more. The boiling point is measured according to JIS K-2254-1998.

As the liquid polyethylene wax having a viscosity of 3000 cps or less at 25 ° C. in (d), all of which are commercially available are Versaflow BASE (viscosity at 25 ° C., 900 cps) and Versaflow LV (25) manufactured by Shamrock. (Viscosity at 25 ° C. 100 cps), Versaflow EV (viscosity at 25 ° C. 1000 cps), Versaflow HV (viscosity at 25 ° C. 3000 cps) and the like.
Of these, Versaflow BASE and Versaflow EV are preferable.
Further, these may be used alone or in combination of two or more. The viscosity is measured by an E-type viscometer at 25 ° C.

The white petrolatum (e) is a paraffin mixture of C ₁₅ H ₃₂ to C ₂₀ H ₄₂ , and CAS No. 8009-03-8 is preferable.

It is desirable that the ultraviolet curable composition used in the ultraviolet curable printed matter of the present invention contains a photopolymerization initiator (f) having a molar extinction coefficient of 2000 ml / g · cm or less in a wavelength region of 300 nm or more. If the molar extinction coefficient in the wavelength region of 300 nm or more is 2000 ml / g · cm or less, even if the addition amount is increased, the curing of the ultraviolet cured product proceeds more than necessary at the time of printing, or the ultraviolet curing is caused by the change over time of the printed matter. It is possible to prevent the degree of hardening of the object from further progressing and the deinkability from being lowered.
Further, the photopolymerization initiator (f) having a molar extinction coefficient of 2000 ml / g · cm or less in the wavelength region of 300 nm or more cannot be effective as a curing agent even if the addition amount thereof is extremely increased. If the amount added is appropriate, the plasticity of the composition can also be imparted. The amount of the photopolymerization initiator (f) added is preferably 3.0 to 10.0% by mass based on the total amount of the composition. When the total amount of the photopolymerization initiator (f) is 3.0% by mass or more of the total amount of the composition, the degree of curing of the ultraviolet cured product further progresses due to the aging of the printed matter due to its efficacy as a plasticizer, and deinking. On the contrary, it is possible to prevent the sex from deteriorating. If the total amount of the photopolymerization initiator (f) is 10.0% by mass or less of the total amount of the composition, the high sensitivity is less likely to be cured than the conventional ultraviolet curing type system without imparting excessive plasticity. Even in a UV system or a UV-LED system, curability that does not cause any problem in actual work can be obtained.

As the photopolymerization initiator (f) having a molar extinction coefficient of 2000 ml / g · cm or less in the wavelength region of 300 nm or more, if it has this physical property, it is an intramolecular cleavage type photopolymerization initiator and hydrogen extraction type light. It can be used without distinction such as a polymerization initiator.
Specifically, 4'-(2-hydroxyethoxy) -2-hydroxy-2-methylpropiophenone (CAS number: 106795-53-9), oxylan, 2-methyl-, polyoxy, biz (2-benzoyl). Benzoyl), triblock, and α-hydro-ω-[(2-benzoylbenzoyl) oxy] poly [oxy (methyl-1,2-ethanezyl] -2,2-bis (hydroxymethyl) -1,3-propa Mixtures of nediol (4: 1, CAS number: 1182753-56-5 and CAS number: 119-61-9), 4-methylbenzophenone (CAS number: 134-84-9), poly (oxy-1,2). -Ethandil), α- (2-benzoylbenzoyl) -ω- [(2-benzoylbenzoyl) oxy]-(CAS number: 1246144-73-9), oligo [2-hydroxy-2-methyl-1- (4) -Methylvinyl) phenyl] Propane-1-one (CAS number: 163702-01-0), 1-propanol, 1- [2,3-dihydro-1- [4- (2-hydroxy-2-methyl-1) -Oxopropyl) phenyl] and 1-propanol, 1- [2,3-dihydro-3- [4- (2-hydroxy-2-methyl-1-oxopropyl] phenyl] -1,1,3-trimethyl-1H -Mix of -Inden-5-yl] -2-hydroxy-2-methyl-1,1,3-trimethyl-1H-Inden-5-yl] -2- (CAS number: 164578-07-8), 4-isopropyl- 4'-Methyldiphenyliodonium tetrakis (pentafluorophenyl) borate (CAS number: 178233-72-2), methylbenzoylformate (CAS number: 15205-55-0), 2,2-dimethoxy-2-phenylacet Fenon (CAS number: 24650-42-8), 2-dimethylamino-ethylbenzoate (CAS number: 2208-5-1), 2-hydroxy-1- [4- [4- (2-hydroxy-2-) Methylpropionyl) benzyl] phenyl] -2-methylpropan-1-one (CAS number: 474510-57-1), 4-methylphenyl [4- (2-methylpropyl) phenyl]-, hexafluorophosphine (1) -), Iodonium (CAS number: 344562-80-7), a mixture of carboxymethoxybenzophenone diester and polyethylene glycol 200 (CAS number: 515136) -49-9), Mixture of Diester of carboxymethoxybenzophenone and Polyethylene Glycol 250 (CAS Number: 515136-48-8), 9- [4- (2-Hydroxyethoxy) phenyl] thiantrenium hexafluorophosphate (CAS) Number: 492466-56-5), Methyl 2-benzoylbenzoate (CAS number: 606-28-0), 2,2-diethoxyacetophenylone (CAS number: 6175-45-7), 1-propanol, 1,1'-(Oxide-4,1-Phenen) Bis [2-Hydroxy-2-methyl] (CAS Registry Number: 71868-15-0), Ethyl (2,4,6-trimethylbenzoyl) -Phenylphosphinate (CAS Number: 84434-11-7), 1-Hydroxycyclohexyl-phenyl-ketone (CAS Number: 947-19-3), 2-Hydroxy-2-Methyl-1-phenyl-Propane-1-one, (CAS). Number: 7473-98-5), 4'-(2-Hydroxyethoxy) -2-hydroxy-2-methylpropiophenone (CAS Number: 106797-53-9), 4,4'-dimethyl-diphenyliodonium hexa Fluorophosphate (CAS Number: 60565-88-0), Oligo [2-Hirodoxy-2-Methyl-4- (4-methylvinyl) phenyl] Propane-1-one (CAS Number: 163702-01-0) , Phenylbis (2,4,6-trimethylbenzoyl) phosphine-oxide (CAS number: 162881-26-7), 2-hydroxy-2-methyl-propiophenone (CAS number: 7473-98-5), 1 , 2-Propadion, 1-Phenyl-, 2- [O- (ethoxycarbonyl) oxime] (CAS Registry Number: 65894-76-0),
2- (2-Chlorophenyl) -1- [2- (2-chlorophenyl) -4,5-diphenyl-1,3-diazol-2-yl] -4,5-diphenylimidazole (CAS number: 7189-82-) 4), Triarylsulfonium hexafluoroantimonate salt in propylene carbonate (CAS number: 104558-94-3), triarylsulfonium hexafluorophosphate salt in propylene carbonate (CAS number: 104558-95-4), diphenyl- 2,4,6-trimethylbenzoylphosphine-oxide (CAS number: 75980-60-8), 1,1'-bi-1H-imidazole, 2,2'-bis (2-chlorophenyl) -4,4', 5,5'-Tetraphenyl- (CAS Number:
1707-68-2) and the like can be mentioned.
Among them, 1-hydroxycyclohexyl-phenyl-ketone (CAS number: 947-19-3), 2-hydroxy-2-methyl-1-phenyl-propane-1-one, (CAS number: 7473-98-5) are preferable. Further, these may be used alone or in combination of two or more.

Next, in the ultraviolet curable composition used in the ultraviolet curable printed matter, in order to accelerate the ultraviolet curing of the composition, a photopolymerization initiator having a molar absorption coefficient of 2000 ml / g · cm or less in the wavelength region of 300 nm or more. An appropriate amount of the photopolymerization initiator (g) other than (f) may be used. The photopolymerization initiator (g) is a photopolymerization initiator whose curability increases as the amount of the photopolymerization initiator (g) is increased within an appropriate range, and plasticity unlike the photopolymerization initiator (f) cannot be expected. be.
Examples of the photopolymerization initiator (g) include an intramolecular cleavage type photopolymerization initiator and a hydrogen abstraction type photopolymerization initiator. Examples of the intramolecular cleavage type photopolymerization initiator excluding the photopolymerization initiator (f) include acetphenone compounds of diethoxyacetophenone; 1- [4- (phenylthio)-, 2- (O-benzoyloxime)]. Oxygen compounds such as 1- [9-ethyl-6- (2-methylbenzoyl) -9H-carbazole-3-yl]-, 1- (O-acetyloxime), 3,6-bis (2-methyl-) 2-Molphorinopropanol) -Carbazole compounds such as -9-butylcarbazole, benzoin compounds such as benzoin, benzoin methyl ether, benzoin isopropyl ether; 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) ) Butane-1-one, 2- (dimethylamino) -2- (4-methylbenzyl) -1- (4-morpholinophenyl) butane-1-one, 2-methyl-2-morpholino ((4-methylthio) ) Phenyl) Propane-1-one, 2-Methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) ) -Aminoalkylphenone compounds such as butanone; bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, 2,4,6-trimethylbenzoyldiphenylphosphinoxide, bis (2,6-dimethoxybenzoyl) Acylphosphine oxide-based compounds such as -2,4,4-trimethyl-pentylphosphinoxide; benzyl, methylphenylgrioxy ester and the like can be mentioned.

Further, as for the hydrogen abstraction type photopolymerization initiator, if it is other than the photopolymerization initiator (f), a photopolymerization initiator such as a benzophenone-based compound, a thioxanthone-based compound, or an aminobenzophenone-based compound may be used. good. These photopolymerization initiators may be used alone or in combination of two or more.
Among these, the hybrid UV system that uses one metal halide lamp that cuts infrared rays and short wavelengths, and the energy-saving UV system that reduces the number of conventional UV lamps from the usual 3 to 4 to one. Aminoalkylphenone-based compounds are preferred, and 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one is particularly preferred.
Further, particularly when a UV-LED light source that generates ultraviolet rays having an emission peak wavelength in the range of 350 to 420 nm is used as an active energy radiation source, an aminoalkylphenone-based compound, an acylphosphine oxide-based compound, and an aminobenzophenone-based compound are used. May be used alone or in combination of two or more. Of these, 2,4,6-trimethylbenzoyldiphenylphosphine oxide and 4,4'-bis (diethylamino) benzophenone, which are acylphosphine oxide compounds, are particularly preferable.

The amount of the photopolymerization initiator (g) used is preferably in the range of 1 to 10% by mass of the total solid content in the ultraviolet curable composition. That is, when the total amount of the photopolymerization initiator (g) used is 1% by mass or more, good curability can be obtained, and when it is 10% by mass or less, the unreacted polymerization initiator is contained in the cured product. It is possible to avoid problems such as migration, solvent resistance, weather resistance and other deterioration of physical properties due to the residual material.

As the ultraviolet curable composition used in the ultraviolet curable printed matter of the present invention, an ultraviolet curable monomer such as a (meth) acrylic monomer may be used. Here, (meth) acrylic is a general term for acrylic and methacrylic.

Examples of the (meth) acrylic monomer include unsaturated carboxylic acids such as acrylic acid and methacrylic acid or esters thereof, such as alkyl (meth) acrylate, cycloalkyl (meth) acrylate, alkyl halide (meth) acrylate, and alkoxyalkyl (. Of meth) acrylate, hydroxyalkyl (meth) acrylate, aminoalkyl (meth) acrylate, allyl (meth) acrylate, glycidyl (meth) acrylate, benzyl (meth) acrylate, phenoxy (meth) acrylate, alkylene glycol, polyoxyalkylene glycol Mono- or di (meth) acrylates, trimethylolpropantri (meth) acrylates, pentaerythritol tetra (meth) acrylates, and other (meth) acrylamides or derivatives thereof, such as mono- or di-substituted with alkyl or hydroxyalkyl groups (mono or di (meth) acrylates). Examples thereof include allyl compounds such as meth) acrylamide, diacetone (meth) acrylamide, N, N'-alkylene bis (meth) acrylamide, allyl alcohol, allyl isocyanate, diallyl phthalate, triallyl isocyanurate and the like.

As another example of the (meth) acrylic monomer, polyethylene glycol having an ethylene glycol unit in the molecule (n is 3 or more and about 14 or less) di (meth) acrylate and phenol EO modified (n is 3 or more). (Approximately 14 or less) (meth) acrylate, 2-hydroxyethyl (meth) acrylate having a hydroxyl group in the molecule, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, pentaerythritol tetra (meth) Examples thereof include acrylate and monohydroxyethyl (meth) phthalate.
These (meth) acrylic monomers may be used alone or in combination of two or more.

Examples of the (meth) acrylic monomer include methyl, ethyl, propyl, butyl, amyl, 2-ethylhexyl, isooctyl, nonyl, dodecyl, hexadecyl, octadecyl, cyclohexyl, benzyl, methoxyethyl, butoxyethyl, phenoxyethyl and nonylphenoxy. (Meta) acrylates having substituents such as ethyl, glycidyl, dimethylaminoethyl, diethylaminoethyl, isobornyl, dicyclopentanyl, dicyclopentenyl, dicyclopentenyloxyethyl, ω-carboxy-polycaprolactone monoacrylate, phthalic acid Monohydroxyethyl acrylate, 2-hydroxy-3-phenoxypropyl acrylate, vinylpyrrolidone, acryloylmorpholin, monofunctional monomers such as N-vinylformamide,
1,3-butylene glycol, 1,4-butanediol, 1,5-pentanediol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, neopentylglycol, 1,8-octanediol, Di (meth) acrylates such as 1,9-nonanediol, tricyclodecanedimethanol, ethylene glycol, polyethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, and tris (2-hydroxyethyl) isocyanurate. Di (meth) acrylate, 2- (2-vinyloxyethoxy) ethyl (meth) acrylate, di (meth) acrylate of diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of openylglycol. , Di (meth) acrylate of diol obtained by adding 2 mol of ethylene oxide or propylene oxide to 1 mol of bisphenol A, and triol obtained by adding 3 mol or more of ethylene oxide or propylene oxide to 1 mol of trimethylolpropane. Di or tri (meth) acrylate, di (meth) acrylate of diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of bisphenol A, trimethylolpropanetri (meth) acrylate, pentaerythritol tri (meth). Examples thereof include polyfunctional monomers such as acrylate, poly (meth) acrylate of dipentaerythritol, ethylene oxide-modified phosphoric acid (meth) acrylate, and ethylene oxide-modified alkyl phosphate (meth) acrylate. These can be used in combination of two or more.

Further, as the ultraviolet curable composition used in the ultraviolet curable printed matter of the present invention, the polyfunctional acrylate is more preferable.
Examples of the polyfunctional acrylate include dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate mixture (DPHA), trimethylolpropane tetraacrylate (DTMPTA), ethylene oxide-modified trimethylolpropane triacrylate (EOTMPTA), and the like. Examples thereof include propylene oxide-modified trimethylolpropane triacrylate (POTMPTA) and trimethylolpropane triacrylate (TMPTA). These may be used alone or in combination of two or more. In order to maintain appropriate curability and enhance deinkability, it is better than using a mixture of dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate (DPHA), which has a high acrylate functional group. Ditrimethylolpropane tetraacrylate (DTMPTA), which has a slightly low number of functional groups, is suitable.
The amount of the ditrimethylolpropane tetraacrylate (DTMPTA) added is preferably 10% by mass or more and 50% by mass or less of the total amount of the ultraviolet curable composition.

It is preferable to use an inert resin as the binder resin of the ultraviolet curable composition used in the ultraviolet curable printed matter of the present invention. The inert resin is a resin that does not participate in radical polymerization by irradiation with ultraviolet rays, that is, does not cause radical polymerization by ultraviolet rays, and the type of the resin is not particularly limited.
Specific examples of the inert resin include polyurethane resin, amino resin, phenol resin, polyamide, cellulose derivative, fluororesin, diallyl phthalate resin, vinyl resin, polyolefin, natural rubber derivative, acrylic resin, ketone aldehyde condensation resin, and epoxy resin. Examples thereof include polyester, polystyrene, alkyd resin, rosin-modified alkido resin, and linseed oil-modified alkido resin, and these may be used alone or in combination of two or more. Among them, the ketone aldehyde condensed resin is preferable because it can be obtained as a commercially available product and has excellent compatibility with pigments and excellent fluidity.
The amount of the inert resin added is preferably 10 to 40% by mass based on the total amount of the ultraviolet curable composition.

In the ultraviolet curable composition used in the ultraviolet curable printed matter of the present invention, wax can be added for the purpose of improving the curability. The waxes include paraffin wax, carnauba wax, mitsuro, microcrystallin wax, polyethylene wax, polyethylene oxide wax, polytetrafluoroethylene wax, amido wax and other waxes, and coconut oil fatty acids and soybean oil fatty acids of about C8 to C18. Fatty acids and the like in the range can be mentioned.

Further, the present invention is the method for producing an ultraviolet curable printed matter, wherein an image of an ultraviolet curable composition is formed on a substrate by offset printing (I) and a step (II) of irradiating with ultraviolet rays. The present invention relates to a method for producing an ultraviolet curable printed matter, which is characterized by having the printed matter in this order.

The base material is not particularly limited, and is, for example, high-quality paper, coated paper, art paper, imitation paper, thin paper, cosmetics and beverages used for printed matter such as catalogs, posters, leaflets, books, magazines, direct mails, and pamphlets. , Paper such as thick paper used for packaging pharmaceuticals, toys, equipment, etc. can be used. Of these, high-quality paper or coated paper is preferable, and as for the degree of deinking property, the ink easily penetrates into the coating agent, so that the effect on the coated paper is great.

Examples of the ultraviolet curable ink corresponding to the ultraviolet curable composition used in the method for producing an ultraviolet curable printed matter of the present invention include UV-LED dedicated offset ink compatible with an LED system using a UV-LED light source, and infrared rays and short lengths. High-sensitivity ultraviolet (HUV) compatible with hybrid UV systems that use one metal halide lamp with a cut wavelength, and energy-saving UV systems that reduce the number of conventional UV lamps from the usual 3 to 4 to 1 to 2. ) Curable offset ink is more preferred.

As the color of the ultraviolet curable offset ink, yellow, red, indigo, and black process inks are preferable. These four colors may be used as a single color, or two to four colors may be overprinted.
Based on coated paper, which tends to be more difficult to deink than high-quality paper, its print density, dot gain when halftone dots are reproduced, and hue are within the range of the world standard offset printing certification standard (ISO12647). And with the Gretag Macbeth densitometer, the yellow density is 1.3 ± 0.05, the red density is 1.4 ± 0.05, the indigo density is 1.4 ± 0.05, and the black density is 1.75 ± 0.05. It is preferable that it is printed.

The pigment used for the ultraviolet curable offset ink is not particularly limited, and either an untreated pigment or a treated pigment can be applied.

Specifically, known inorganic pigments and organic pigments can be used. Examples of the inorganic pigment include iron oxide, carbon black produced by a known method such as a contact method, a furnace method, and a thermal method. Examples of organic pigments include azo pigments (including azo lakes, insoluble azo pigments, condensed azo pigments, chelate azo pigments, etc.) and polycyclic pigments (for example, phthalocyanine pigments, perylene pigments, perinone pigments, anthraquinone pigments, quinacridone pigments, and dioxazines). Pigments, thioindigo pigments, isoindolinone pigments, quinoflorone pigments, etc.), dye chelate (for example, basic dye type chelate, acid dye type chelate, etc.), nitro pigments, nitroso pigments, aniline black and the like can be used.
For black ink, carbon black is suitable.

Examples of the pigment used in the black ink include carbon black produced by a known method such as a furnace method, a thermal method, and a contact method. For example, Raven 14, Raven 450, Raven 860 Ultra, Raven 1035, and the like. Raven 1040, Raven 1060 Ultra, Raven 1080 Ultra, Raven 1180, Raven 1255 (above, Colombian Chemical), Legal 400R, Legal 330R, Legal 660R, Mogle L (above, Cabot), MA7, MA8, MA11 (above) , Mitsubishi Chemical Corporation) and the like, and these may be used alone or in combination of two or more as appropriate.

Specific examples of the pigment used in the yellow ink include C.I. I. Pigment Yellow 1, 2, 12, 13, 14, 16, 17, 73, 74, 75, 83, 93, 95, 97, 98, 109, 110, 114, 120, 128, 129, 138, 150, 151, 154, 155, 174, 180, 185 and the like can be mentioned.

Specific examples of pigments used in magenta ink include C.I. I. Pigment Red 5, 7, 12, 48 (Ca), 48 (Mn), 57 (Ca), 57: 1, 112, 122, 123, 146, 168, 176, 184, 185, 202, 209, 269, etc. C. I. Pigment Violet 19, 23 and the like.

Specific examples of the pigment used in the cyan ink include C.I. I. Pigment Blue 1, 2, 3, 15, 15: 3, 15: 4, 16, 22, 60, 63, 66 and the like.

In addition, inorganic fine particles may be used as the extender pigment in the ultraviolet curable offset ink. Inorganic fine particles include inorganic coloring pigments such as titanium oxide, graphite, and zinc flower; lime carbonate powder, precipitated calcium carbonate, gypsum, ChinaClay, silica powder, diatomaceous earth, talc, kaolin, alumina white, barium sulfate, stearer. Inorganic pigments such as aluminum acetate, magnesium carbonate, barite powder, abrasive powder; and other inorganic pigments, silicone, glass beads, and the like can be mentioned. By using these inorganic fine particles in the range of 0.1 to 20% by mass of the total amount of ink, it is possible to obtain effects such as adjusting the fluidity of the ink, preventing misching, and preventing penetration into a printing substrate such as paper. be.

In the ultraviolet curable offset ink, as other formulations of the above-mentioned components, a polymerization inhibitor, a dye, an organic solvent, an antistatic agent, a defoaming agent, a viscosity modifier, a light-resistant stabilizer, a weather-resistant stabilizer, and a heat-resistant stable. Additives such as agents, UV absorbers, antioxidants, leveling agents, pigment dispersants and the like can be used.

In the production of the ultraviolet curable offset ink, the coloring pigment, the extender pigment, the polymerizable acrylate monomer, the binder resin, the photopolymerization initiator, the polymerization inhibitor, the wax, and the like are assisted in the production of the ultraviolet curable offset ink, as in the conventional ultraviolet curable offset ink. It is manufactured by blending an agent or the like, stirring and mixing with a mixer or the like, and kneading the meat using a disperser such as a three-roll mill or a bead mill.

In the method for producing an ultraviolet curable printed matter of the present invention, the printing machine used in the step (I) of forming an image of an ultraviolet curable composition on a substrate by offset printing is the world standard offset printing certification standard (ISO12647). ), The dot gain when reproducing the mesh dots, and the offset printing machine that can print with the hue, regardless of the mechanism, size, and manufacturer of the printing machine, light off printing from a large machine of A full size. It doesn't matter whether it is a sheet-fed machine or a rotary machine. Further, a test printing machine such as a color developing machine or a proofing machine may be used.

In the ultraviolet irradiation system used in the step (II) of irradiating ultraviolet rays in the method for producing an ultraviolet curable printed matter of the present invention, an LED system using only one UV-LED light source and only one metal halide lamp are used. However, a hybrid UV system that cuts infrared rays and short wavelengths of about 300 nm or less, an energy-saving UV system that reduces the number of conventional UV lamps from the usual 3 to 4 to 1 to 2 are preferable. In either case, an energy-saving system that suppresses the generation of ozone and heat can be realized.
The wavelength peak of the UV-LED light source is preferably in the range of 365 to 420 nm.

In the method for producing an ultraviolet curable printed matter of the present invention, after undergoing a step (I) of forming an image of an ultraviolet curable composition on the paper as a substrate by offset printing and a step (II) of irradiating with ultraviolet rays in this order. , It is preferable to store the printed matter after aging treatment.
As the aging treatment conditions, it is preferable to control the aging at 60 ° C. for 1 week from printing within the range of room temperature 23 ± 1 ° C. and humidity 50 ± 2%. When the curability of the ultraviolet curable composition on the substrate is excessively promoted beyond these aging conditions, the deinkability tends to decrease.

Hereinafter, the present invention will be specifically described with reference to Examples.
The boiling point according to the present invention was measured according to JIS K-2254-1998.
The viscosity was measured at 25 ° C. using an E-type viscometer (Toki Sangyo model: VISCOMETER TV-25).
The weight average molecular weight (Mw) and the number average molecular weight (Mn) are values measured by gel permeation chromatography (GPC) under the following conditions.

Measuring device: HLC-8220GPC manufactured by Tosoh Corporation
Column: TSK-GUARDCOLUMN SuperHZ-L manufactured by Tosoh Corporation
+ TSK-GEL SuperHZM-M x 4 manufactured by Tosoh Corporation
Detector: RI (Differential Refractometer)
Data processing: Multi-station GPC-8020modelII manufactured by Tosoh Corporation
Measurement conditions: Column temperature 40 ° C
Solvent tetrahydrofuran
Flow velocity 0.35 ml / min Standard: Monodisperse polystyrene Sample: Tetrahydrofuran solution of 0.2% by mass in terms of resin solid content filtered with a microfilter (100 μl)

[Manufacturing of UV curable ink]
According to the compositions of Tables 1 to 6, UV-curable offset inks were obtained by kneading Preparation Examples 1 to 48 with a three-roll mill.
The numerical values in Tables 1 to 6 are mass%.

[Adjustment example 1: Ink ink]
Regarding the black ink of Adjustment Example 1, carbon black (manufactured by Mitsubishi Chemical) 17% by mass as a coloring component, magnesium carbonate TT (manufactured by Naikai Salt Industry Co., Ltd.) 2% by mass as a viscosity and fluidity initiator, and polyethylene wax S-381 as a wax. -N1 (manufactured by Shamrock) 1% by mass, Variplus AP (manufactured by Evonik) which is a ketone aldehyde condensation type inert resin as a binder, 23.5% by mass, and ditrimethylolpropane tetraacrylate (DTMPTA, (Sartomer) as a polymerization diluent. IGM Irgacure907 (α-aminoalkylphenone-based initiator, 2-methyl-1- [4- (methylthio) phenyl] -2-morpho, which corresponds to 46.5% by mass of the photopolymerization initiator (g). Renopropane-1-one, number average molecular weight 279.4) 6% by mass, and EMK (4,4'-bis (diethylamino) benzophenone, manufactured by IMG) 2% by mass, stearer TBH (2-tert) as a polymerization initiator -Butylhydroquinone, manufactured by Daido Kasei Co., Ltd.) 0.1% by mass, and Irgacure 184 (1-hydroxycyclohexylphenylketone, number average molecular weight 204.3) 2% by mass corresponding to the photopolymerization initiator (f) were blended. ..

[Adjustment Examples 2-45: Ink Ink]
For Adjustment Examples 2 to 45, black ink was prepared in the same procedure as in Adjustment Example 1 according to the formulations shown in Tables 1 to 5.

[Adjustment Examples 46 to 48: Color Ink]
As for the indigo, red, and yellow inks, color inks having the same formulations as those of all the adjustment examples of the black inks were prepared. Table 6 shows adjustment examples 46 to 48 as representatives of the formulations of indigo, red, and yellow inks corresponding to the adjustment example 1 of the black ink.
As for the other indigo, red, and yellow inks, color inks corresponding to the black inks of Adjustment Examples 2 to 45 were prepared according to the following.
For all the adjustment examples, the pigment percentage of the indigo ink was 17% by mass of the total amount of ink equivalent to that of the black ink, 18% by mass of the red ink, and 14% by mass of the yellow ink.
As for indigo ink, since the pigment percentage is the same as that of black ink, which is 17% by mass, carbon black shown in adjustment examples 1 to 45 of black ink is replaced with Pigment Blue 15: 4 manufactured by DIC Co., Ltd. All have the same composition as black ink.
As for the red ink, Pigment Red 57: 1 manufactured by DIC Corporation was set to 18% by mass, and the binder resin was all the same as the black ink except that the binder resin was reduced by 1% by mass from the black ink.
As for the yellow ink, Pigment Yellow 13 manufactured by DIC Corporation was used at 14% by mass, and the same composition as that of the black ink was used except that the binder resin was added by 3% by mass from the composition of the black ink.
The difference in pigment percentage for indigo, red, and yellow inks was all adjusted by the amount of binder, and all others had the same composition.

表１～６の数値は質量％である。
各表に示す諸原料及び略を以下に示す。
・カーボンブラック：三菱化学（株）製
・炭酸マグネシウムＴＴ：ナイカイ塩業（株）製
・ワックス：ポリエチレンワックスＳ－３８１－Ｎ１、シャムロック社製
・ジアリルフタレート樹脂：（株）大阪ソーダ社製
・イナート樹脂：ケトンアルデヒド縮合樹脂 Ｖａｒｉｐｌｕｓ ＡＰ、Ｅｖｏｎｉｋ社製
・ＤＴＭＰＴＡ：ジトリメチロールプロパンテトラアクリレート（４官能）、Ｓａｒｔｏｍｅｒ社製
・ＤＰＨＡ：ジペンタエリスリトールペンタ（メタ）アクリレートとジペンタエリスリトールヘキサ（メタ）アクリレート混合物（質量混合比１：３）、Ｓａｒｔｏｍｅｒ社製
・Ｉｒｇａｃｕｒｅ９０７：２－メチル－１－[４－（メチルチオ）フェニル]－２－モルフォリノプロパン－１－オン、数平均分子量２７９．４、ＩＧＭ社製
・ＩｒｇａｃｕｒｅＴＰＯ：２，４，６－トリメチルベンゾイルジフェニルフォスフィンオキサイド、数平均分子量４１８．５、ＩＧＭ社製
・ＥＭＫ：４，４’-ビス(ジエチルアミノ)ベンゾフェノン、数平均分子量３２４．５、ＩＧＭ社製
・重合禁止剤：ステアラーＴＢＨ（２－ｔｅｒｔ－ブチルハイドロキノン）大同化成工業（株）製
・Ｉｒｇａｃｕｒｅ１８４：１－ヒドロキシシクロヘキシル－フェニル－ケトン、数平均分子量２０４．３、ＩＧＭ社製
・Ｉｒｇａｃｕｒｅ１１７３：２－ヒドロキシ－2－メチル－１－フェニル－プロパン－１－オン、数平均分子量１６４．２、ＩＧＭ社製
・アジピン酸ジイソノニル：重量平均分子量３３９、沸点２２７℃、ＣＡＳ番号３３７０３－０８－１、三菱ケミカル（株）製
・セバシン酸ジオクチル：重量平均分子量４２６．７、沸点２５６℃、ＣＡＳ番号１２２－６２－３、米山薬品工業（株）製
・ステアリルアルコール：１－オクタデカノール、沸点３５０℃、ＣＡＳ番号：１１２－９２－５、高級アルコール工業（株）製
・Ｖｅｒｓａｆｌｏｗ Ｂａｓｅ：液状ポリエチレンワックス、２５℃での粘度 ９００ｃｐｓ、シャムロックス社製

The numerical values in Tables 1 to 6 are mass%.
The raw materials and abbreviations shown in each table are shown below.
・ Carbon black: manufactured by Mitsubishi Chemical Co., Ltd. ・ Magnesium carbonate TT: manufactured by Naikai Salt Industry Co., Ltd. ・ Wax: polyethylene wax S-381-N1, manufactured by Shamrock Co., Ltd. ・ Dialyl phthalate resin: manufactured by Osaka Soda Co., Ltd. ・Inert resin: Ketonealdehyde condensation resin Variplus AP, manufactured by Evonik ・ DTMPTA: Ditrimethylol propanetetraacrylate (tetrafunctional), manufactured by Sartomer ・ DPHA: Dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate mixture (Mass mixing ratio 1: 3), manufactured by Sartomer, Irgacure 907: 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropane-1-one, number average molecular weight 279.4, manufactured by IGM. -Irgacure TPO: 2,4,6-trimethylbenzoyldiphenylphosphine oxide, number average molecular weight 418.5, manufactured by IGM-EMK: 4,4'-bis (diethylamino) benzophenone, number average molecular weight 324.5, manufactured by IGM -Polymer banning agent: Stellar TBH (2-tert-butylhydroquinone) manufactured by Daido Kasei Kogyo Co., Ltd.-Irgacure184: 1-hydroxycyclohexyl-phenyl-ketone, number average molecular weight 204.3, manufactured by IGM-Irgacure1173: 2-hydroxy -2-Methyl-1-phenyl-propane-1-one, number average molecular weight 164.2, manufactured by IGM-Diisononyl adipate: weight average molecular weight 339, boiling point 227 ° C, CAS number 33703-08-1, Mitsubishi Chemical ( Made by Co., Ltd. ・ Dioctyl sebacate: Weight average molecular weight 426.7, boiling point 256 ° C, CAS number 122-62-3, manufactured by Yoneyama Yakuhin Kogyo Co., Ltd. ・ Stearyl alcohol: 1-octadecanol, boiling point 350 ° C, CAS number : 112-92-5, manufactured by Higher Alcohol Industry Co., Ltd.-Versaflow Base: liquid polyethylene wax, viscosity at 25 ° C, 900 cps, manufactured by Shamrocks.

Table 6 shows adjustment examples 46 to 48 as representatives of the formulations of indigo, red, and yellow inks corresponding to the adjustment example 1 of the black ink.
As for the other indigo, red, and yellow inks, color inks corresponding to the black inks of Adjustment Examples 2 to 45 were prepared according to the above paragraph [0060].

[Example 1]
Using the adjustment example 1 (black), adjustment example 48 (indigo), adjustment example 47 (red), and adjustment example 46 (yellow) thus obtained, the following steps of printing, ultraviolet irradiation, and aging are performed. An ultraviolet curable offset 4-color printed matter was produced.
[Examples 2 to 40]
Using the same procedure as in Example 1, indigo, red, and yellow inks in which the amount of binder is adjusted according to the paragraph [0060] of Adjustment Example 2 (black) and Adjustment Example 2 are used, and UV curable offset 4-color printing is performed. A printed matter was produced.
[Ratio Examples 1 to 6]
In the same procedure as in Example 1, for Comparative Examples 1 to 6, the black ink of Adjustment Examples 41 to 46 and the indigo, red, and yellow inks whose binder amount was adjusted according to the paragraph [0060] were used and UV-cured. A four-color printed matter with a mold offset was produced.

[Manufacturing method of UV-curable printed matter]
Top Coat Plus (coated paper manufactured by Oji Paper Co., Ltd., 57.5 kg,) using the Komori Lithrone G40 offset printing machine (manufactured by Komori Corporation) for the four colors of the obtained black, indigo, red, and yellow ultraviolet curable offset inks. "JPMA Color Chart 2002" pattern that reflects the color management standard Japan Color 2001 in A size) is printed in accordance with the world standard offset printing certification standard (ISO12647), dot gain when reproducing mesh dots, hue. In order to match, the black density is 1.75, the indigo density is 1.4, the red density is 1.4, and the yellow density is 1.3 (measured by the reflection densitometer Spectroscan, OffsetT, paper white zero point adjustment manufactured by Gretag Macbeth). After confirming that the entire surface of the paper was uniform, 1000 sheets were printed in the order of ink, indigo, red, and yellow at a printing speed of 15,000 sheets per hour.
As the dampening water supplied to the plate surface, an aqueous solution obtained by mixing 98% by mass of tap water and 2% by mass of an etchant (FST-700, manufactured by DIC) was used.

[Curing method using a UV lamp light source]
The curing method was carried out by the following three methods using an online ultraviolet irradiation device mounted on the Komori Lithrone G40.
Tables 7 to 10 showing Examples 1 to 40 and Table 11 showing Comparative Examples 1 to 6 used (i) one Komori-sha hybrid lamp (HUV) that cuts infrared rays and short wavelengths immediately after printing (i). In a hybrid UV system using 160 W / cm ² , 100% output), irradiation was performed so that the amount of irradiation energy at one time was 160 mJ / cm ² .
(Ii) Immediately after printing, a single irradiation energy is used in a UV-LED system using one LED 12 W / cm ² lamp (emission wavelength: 385 nm, peak intensity: 500 mW / cm ² 100% output) manufactured by Eye Graphics. The irradiation was performed so that the amount was 50 mJ / cm ² .
(Iii) Irradiation with a conventional ultraviolet irradiation system using one water-cooled metal halide lamp manufactured by Eye Graphics (1 lamp 120 W / cm ² , 100% output) so that the amount of irradiation energy at one time is 160 mJ / cm ² . bottom.
Tables 7 to 10 showing Examples 1 to 40 and Table 11 showing Comparative Examples 1 to 6 show the ultraviolet irradiation systems used, respectively.

[Aging of UV curable printed matter]
The prepared UV-curable printed matter was uniformly aged at 60 ° C. for 1 week, and then stored in an environment of room temperature 23 ± 1 ° C. and humidity 50 ± 2% for another 10 days.

[Preparation for dirt evaluation 1: Pulp dissociation treatment]
As the dirt evaluation sample material, 17.4 g of the stored UV-curable printed matter and 40.6 g of unprinted blank paper are used.
Dirt means a black dot that could not be completely dissociated, and if there is a lot of floss, the deinkability is poor and it is judged that it is not suitable for recycling.
First, put it in a 2 liter pulper, add 1.5 L of warm water at 30 ° C, 7 ml of 3.75% sodium hydroxide aqueous solution, and 7 ml of a deinking agent (DI7027 manufactured by Kao Corporation) diluted to 1.5%. Then, add 58 g of the dirt evaluation sample material, cover it, stir, and start the dissolution.
Stir at 3000 rpm, 2 minutes after the start of stirring when the stirring became stable and no scattering of the sample was observed, carefully remove the lid, wash the sample adhering to the lid etc. into the tank with a small amount of water, and then continue. If the sample is scattered on the wall surface of the pulper, wash it into the tank with a small amount of water. The stirring time is 20 minutes in total, and after the disintegration is completed, the sample is concentrated by hand drawing to 625 g using a 150 mesh (opening: 103 μm) sieve.

[Preparation for dirt evaluation 2: Pulp dilution]
Add 1350 mL of pure water at room temperature to 2 L pulper and re-dissociate with the concentrated sample for 1 minute. Next, transfer the sample from 2 L pulper to a 10 L bucket, add warm water at 30 ° C., and dilute to 5.4 kg (pulp concentration about 1%).

[Preparation for dirt evaluation 3: Pulp separation]
4.3 kg is separated from the sample diluted in the previous section, and flotation is performed.

[Preparation for dirt evaluation 4: Floatation]
Floatation is conducted by JTAPPI. The device (floatator) specified in No. 39 is used. Prior to the test, fill the tank with warm water at 30 ° C. to stabilize the temperature.
Next, hot water was discharged, 4.3 kg of the sample was put into a floatator, and while supplying 4 L / min of air while rotating at a screw of 1500 rpm, the floss was continued for 10 minutes and flossed evenly every 20 seconds. And perform flotation.
Floss is collected, filtered and dried. If the amount of floss is in the range of 5 to 15 g, it is normal, and if it deviates significantly, it is necessary to exclude it from the test and start over.

[Preparation for evaluation of dirt 5: Collection of sample]
Next, the rotation of the screw of the floatator and the supply of air are stopped, the lower plug is removed, and the sample in the floatator tank is collected. Further, the inside of the tank is washed with a small amount of water, and the washing liquid is added to the sample.

[Preparation for evaluation of dirt 6: Dilution of sample and pH adjustment]
Next, water is added to the collected sample to dilute the total amount to 8 kg, and then an aluminum sulfate solution is added to adjust the pH to 5.3.

[Preparation for evaluation of dirt 7: Papermaking / drying]
Wet paper is made using a 150 mesh (opening: 103 μm) brass wire mesh with a JIS standard round hand plow machine (φ160 mm) specified by JIS P 8222, sandwiched between new filter papers, and pressed at 410 kPa pressure for 5 minutes. And dehydrate. Subsequently, it was completely dried at 50 ° C. for 10 minutes using a hot air circulation type dryer to obtain recycled paper.
Adjust the sample amount so that the weight of the recycled paper after drying is 60 g, and make 5 or more sheets. The operation of papermaking is based on JIS P 8222.

[Evaluation method 1: Evaluation of the number of dirt roads]
For the 5 recycled papers obtained in the previous section, remove impurities such as metal pieces that are clearly not derived from the ink, and use the measuring device for the microscope 3D scanner equipped with the dirt counter software to "JISP8208". With reference to "Pulp-Measurement method for impurities", measure the number of darts with an average particle size of 250 μm or more per 1 m square of recycled paper as a threshold. The measured value was the average value of 5 recycled paper sheets.

[Evaluation method 2: UV curability of printed matter]
Immediately after irradiation with ultraviolet rays, the curability was visually evaluated in the following 10 stages by confirming the presence or absence of scratches on the surface of the developed material by the nail scratch method. With a composition in which the ink cured film is scratched by rubbing with a nail, the printed matter is easily damaged in each process such as cutting, box making, and transportation of the printed matter.
If the evaluation is 5 or higher, it is regarded as a usable level.

10: No scratches are generated by nail scratches, and the curability is the best.
Curability according to 9:10 (best) was confirmed.
8: Slight scratches are seen on the nail scratches.
Medium curability of 7: 8 (small scratches) and 6 (good) was confirmed.
Medium curability of 6: 7 and 5 (usable level) was confirmed.
5: Scratches are seen on the nail scratches, but it is at a usable level.
4: Only 5 (usable level) is not reached.
3: Scratches are generated on the nail scratches, and it cannot be said that the curability is sufficient.
Medium curability of 2: 3 (insufficient curing) and 1 (defective).
1: Claw scratches easily cause scratches and have the worst curability.

[Evaluation method 3: Film strength of printed matter image line]
The solid part of each of the four colors of the printed matter was rubbed 100 times back and forth with a cotton swab containing an aqueous solution of sodium hydroxide adjusted to pH 10.5, and the degree of peeling of the cured film was visually evaluated in the following four stages.
If it is △ or higher, it is considered to be usable.

◎: Does not peel off at all ○: Rubbing marks remain, but hardly peel off.
Δ: Slight peeling is seen, but it is a usable level.
X: It easily peels off after 3 round trips.

Tables 7 to 11 show the evaluation results of the printed matter using the four colors of the ultraviolet curable offset ink. In addition, the adjustment example is shown as a representative of black ink. In addition, the "(meth) acryloyl group concentration (mmol / g)" in each monomer is also described.
The "(meth) acryloyl group concentration" was calculated by applying the following formula.

[Calculation formula for (meth) acryloyl group concentration]
"(Meta) acryloyl group concentration (mmol / g)" = (meth) acrylate (D) number of (meth) acryloyl groups in the molecule ÷ {weight average molecular weight of (meth) acrylate (D)} × 1,000 × {( Meta) Mass of acrylate (D) (g)} ÷ Total mass of ink (g)
Taking Example 1 using Adjustment Example 1 as an example, “(meth) acryloyl group concentration” = 4 (functional number of DTMPTA) ÷ (467 × 1000 × 46.5) ÷ 100 = 3.98 mmol / g. Become.
The mixture of DPHA: dipentaerythritol penta (meth) acrylate (5-functional) and dipentaerythritol hexa (meth) acrylate (6-functional) (mass mixing ratio 1: 3) was calculated as a weight average molecular weight of 578 and 6-functional. ..

The ultraviolet curable printed matter described in the examples is not inferior to the curability and film strength of the printing ink film in the image area, and can also have the deinking property in the paper recycling process.

Claims (6)

An ultraviolet curable printed matter having a cured image of an ultraviolet curable composition provided on a substrate by offset printing, wherein the average particle size of the dirt after deinking treatment is 250 μm or more, and the number of dirt is 70,000 / m. ² or less ,
An ultraviolet curable printed matter, wherein the ultraviolet curable composition contains at least one selected from the following (a) to (e) in an amount of 3.0 to 10% by mass based on the total amount of the composition.
(A) Adipate ester
(B) Sebacic acid or sebacic acid ester
(C) Fatty acid alcohol having a boiling point of 260 ° C. or higher
(D) Liquid polyethylene wax having a viscosity at 25 ° C. of 3000 cps or less.
(E) White petrolatum The UV-curable printed matter according to claim 1, wherein the (meth) acrylate compound contained in the UV-curable composition has a (meth) acryloyl group concentration of 2.0 to 7.0 mmol / g. The ultraviolet curable printed matter according to claim 1 or 2, wherein the ultraviolet curable composition contains at least one selected from the following (a) to (c) in an amount of 3.0 to 10.0% by mass based on the total amount of the composition.
(A) Adipate (b) Sebacic acid or sebacic acid ester (c) Stearyl alcohol or 1-octadecanol The ultraviolet curable according to any one of claims 1 to 3, wherein the ultraviolet curable composition contains a photopolymerization initiator (f) having a molar extinction coefficient of 2000 ml / g · cm or less in a wavelength region of 300 nm or more. Printed matter. The ultraviolet curable printed matter according to claim 4, wherein the photopolymerization initiator (f) is 1-hydroxy-cyclohexyl-phenyl-ketone and / or 2-hydroxy-2-methyl-1-phenyl-propane-1-one. .. The method for producing an ultraviolet curable printed matter according to any one of claims 1 to 5.
Step (I) of forming an image of an ultraviolet curable composition on a substrate by offset printing, and
A method for producing an ultraviolet-curable printed matter, which comprises a step (II) of irradiating ultraviolet rays in this order.