JP2007296830A - Film printed matter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide (1) printed matter (laminate) of back printing which combines a white ink layer excellent in homogeneity and concealment nature or front printing in offset color printing on a transparent plastic base, and (2) printed matter of front printing which combines a white ink layer excellent in homogeneity and concealment nature in offset color printing to metallic tone base materials, such as aluminum vapor deposition paper, aluminum laminated paper, etc. <P>SOLUTION: In the case of the back printing, the printed matter is formed by offset printing using color ink including a process color and a special feature on a plastic base, and then, forming the white ink layer using a coater unit installed after an offset printing machine. In the case of the front printing, the printed matter is formed by forming a white ink layer using the coater unit installed in front of the offset printing machine on a plastic base and a metallic base material, and then, offset printing is performed using a color ink including a process color and a special feature. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a printed matter provided with a white ink layer having a uniform and excellent concealment property in order to obtain an excellent print image quality in a printed matter which is back-printed or surface-printed on a substrate such as a transparent plastic.

  Conventionally, when color offset printing is performed on a transparent base material such as a film, white ink is printed on the entire surface or a part thereof by back printing or surface printing in order to make the color printing stand out.

In addition to transparent substrates, for example, when performing offset printing on a substrate other than white, such as a metallic substrate (aluminum-deposited paper, etc.), a white substrate other than white, such as a metallic substrate, is used. The ink is printed on the entire surface or part of it, and offset color printing is superimposed on it to make the offset printing stand out.
The back printing here refers to a printed material in which a pattern or characters are printed on a transparent substrate with a single color or color ink, and the image is observed through a film from the side opposite to the printing surface of the transparent substrate. When white ink is printed on a pattern, the printed image stands out on a white background, and a high-quality image is obtained.
The surface printing refers to a printed material in which a pattern or a character is printed with a single color or color ink, and an image is observed from the printed surface side. In the case of front printing, a white ink is printed and then a pattern is printed.

  Along with the recent improvement in the accuracy of offset printing presses, there has been an increase in printed matter in which a high-precision printed image is formed by offset printing on a transparent plastic substrate or a metallic substrate.

  In addition, due to the diversification of application fields of offset printing machines in recent years, there is a coater unit before and after the offset printing machine unit, and a water-based or active energy ray-curable colorless and transparent coating agent is applied simultaneously with offset printing. Became possible.

Patent Document 1 describes a printed matter for display that is offset-printed on a film, in which a translucent white ink layer is provided between two identical picture layers to reduce fading due to an illumination lamp or the like. ing.
In Patent Document 2, color ink, anchor coating agent, overprint varnish, white ink, and the like are printed on a plastic film by flexographic printing. By combining these appropriately, high-quality images and coating film properties are disclosed. A composition for back-printing or surface-printing with a print is described.

Utility Model Registration No. 3065094 Japanese Patent Laying-Open No. 2005-225083

  An object of the present invention is to provide a printed material for back printing or surface printing in which a white ink layer having a uniform and excellent hiding property is combined in offset color printing on a transparent plastic substrate, and an aluminum vapor-deposited paper and an aluminum paste. An object of the present invention is to provide a printed material for surface printing in which a white ink layer having a uniform and excellent hiding property is combined in offset color printing on a metallic substrate such as a slip sheet.

  Conventionally, in offset color printing on a transparent plastic substrate, in order to make the color printing stand out, white ink is printed on the whole surface or a part by back printing or surface printing. In offset color printing on a metallic tone base material, in order to make the color printing stand out, white ink is printed on the entire surface or a part of the surface before printing. The printed layer of these white inks must be uniform with no unevenness and high concealability. Here, color printing includes the case of printing in a single color.

  However, even if an attempt is made to form a uniform and concealing printing layer with white ink using an offset printer, only a thickness of less than 2 microns can be obtained by offset printing, and a uniform white ink layer having sufficient concealing property can be obtained. It was difficult.

  In order to solve this problem, 2 to 4 cylinders of printing units are used, and white ink is overprinted. In this method, for example, 6 to 8 cylinders are required to perform color printing with four colors of processes and overprint with white ink, and printing with a large-scale multicolor printing machine of 6 colors or more, or white ink and color ink Had to be printed separately in two offline steps.

  There is also a method of printing only white ink using a screen printer in order to obtain the concealment property of the white ink layer. In screen printing, a thick printed layer can generally be formed. However, this method cannot be printed in-line (color printing and white ink printing are performed in one process in a single printing machine), and has two problems of offset printing and screen printing, which increases time and cost. there were.

  In order to solve the above-mentioned problems, the inventors used a coater unit attached before and after the offset printing machine on a transparent plastic base material or a metallic tone base material to form a white ink layer having a uniform and excellent concealment property. Invented to form.

  That is, in the case of back printing, the present invention is a printed matter in which a white ink layer is formed using a coater unit installed after the offset printer on a plastic substrate using a single color or color ink. The white ink is an active energy ray curable ink or a warm air drying ink.

  In the case of front printing, the present invention forms a white ink layer on a plastic substrate and a metallic substrate using a coater unit installed in front of an offset printing machine, and then applies a single color or color ink. It is a printed matter that has been offset printed using, and the white ink is an active energy ray curable ink or a warm air drying type ink.

  By using the above means, white ink, which has been conventionally printed using a plurality of printing units, is coated with a coater unit, so that a back-printed printed matter and a surface-printed printed matter having a uniform and excellent hiding white ink layer can be obtained. Can be made. In addition, as in the case of using screen printing together, the time and cost are improved compared to the case where the white ink is applied and the color ink is printed in two separate steps.

The present invention will be described in detail below based on the best mode. In the present specification, “part” and “%” are based on mass unless otherwise specified.
The present invention is characterized in that a white ink having a uniform and excellent concealment property is coated on a transparent plastic substrate or a metallic substrate using a coater unit installed before and after the offset printing machine. As a result, white ink that has been printed using a plurality of printing units can be used to create back-printed and front-printed prints having a white ink layer that is uniform and excellent in concealment by using only the coater unit. It was. Compared to the application of white ink in two off-line processes such as screen printing, the time and cost were significantly improved.

Petroleum solvent component for non-absorbing substrates for offset color printing on transparent plastic substrates such as polypropylene (PP) and polyethylene terephthalate (PET), metallic substrates such as aluminum vapor-deposited paper and aluminum laminated paper A method using an oxidation polymerization type ink having a small amount and a method using an active energy ray curable ink are generally used.
In particular, the active energy ray-curable ink is preferable because it has not only excellent quick drying properties but also good viscosity stability on a printing press. In addition, in this specification, an active energy ray refers to an ultraviolet ray or an electron beam.

As the ink used for forming a white ink layer that is uniform and excellent in hiding property for these offset color prints, the following two types are preferable.
(1) An active energy ray-curable white ink that is cured with an active energy ray mainly composed of a vehicle such as a polyester resin.
(2) Water-based white ink mainly composed of a vehicle such as styrene-acrylic acid resin and dried with warm air.

(Active energy ray-curable white ink)
As the active energy ray curable white ink in the present invention, an active energy ray curable white ink comprising a colorant, a vehicle such as a polyester resin, an acrylate prepolymer or monomer, a photopolymerization initiator, and an additive is suitable.

As the colorant, a titanium oxide pigment used in general white ink, paint, and recording material is used. The rutile type and the anatase type can be used as the titanium oxide, but the rutile type is preferable in order to ensure the density and concealment of the printed matter. The colorant is preferably contained in the ink in a range of 25 to 55% in order to secure the ink concentration and coloring power. More preferably, it is 35 to 55%. Further, by replacing some of the colorants with other organic pigments, inorganic pigments, etc., it is possible to impart color feeling and texture.
As a preferred example, the white ink of the present invention contains at least one selected from the group consisting of PY12, PY13, PR57: 3, PB15: 3, PG7, PV1, and alkali blue toner as a pigment or colorant. 0.05-10 mass parts can be contained with respect to parts. Thereby, a feeling of density and a texture can be imparted to the white ink. When these colorants are about 0.05 to 5 parts by mass, it is more preferable to use a light-resistant pigment.

  Vehicles such as polyester resins include polyester resins, epoxy resins, polyurethane resins, acrylic resins, styrene-acrylic acid copolymer resins, and styrene-maleic acid copolymers used in general UV curable ink resin varnishes (vehicles). A polymer resin, diallyl phthalate resin or the like dissolved in an acrylate monomer described later can be used, but a styrene-acrylic copolymer resin is particularly preferable in terms of fluidity, dispersibility of a colorant, and adhesion to a printing raw material. The resin content is preferably 5 to 25 parts in order to impart sufficient adhesion and fluidity to the ink. More preferably, it is 10-25 parts.

As the acrylate prepolymer, polyester acrylate, epoxy acrylate, urethane acrylate, or the like can be used. Examples of the acrylate monomer include low molecular polyol acrylates used in general ultraviolet curable inks, polyether polyols obtained by adding alkylene oxide to them, polyester polyol acrylates obtained by modifying polybasic carboxylic acids, and the like.
Specifically, dipropylene glycol diacrylate (DPGDA), tripropylene glycol diacrylate (TPGDA), polyethylene glycol diacrylate (PEGDA), trimellilol propane triacrylate (TMPTA), ethoxy 3 mol modified trimethylol propane triacrylate ( EO3TMPTA), ditrimethylolpropane tetraacrylate (DTMPTA) and the like can be used alone or in combination. In particular, an acrylate of a low molecular polyol such as DPGDA is preferable in terms of ink fluidity, curability, and adhesion to a substrate.

  The content of these acrylate monomers in the ink is preferably 10 to 50% in order to impart sufficient fluidity to the ink. More preferably, it is 20 to 50%. Moreover, the resin varnish (vehicle) can also be created by heating and mixing one or more of these acrylate monomers with the aforementioned resin component.

When the active energy ray-curable white ink of the present invention is of a type that is cured by ultraviolet rays, it is necessary to contain a photopolymerization initiator. A sensitizer can be used in combination with the photopolymerization initiator as necessary.
Specific examples of photopolymerization initiators and sensitizers used for UV curing include 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, 2-hydroxy- 2-methyl-1-phenyl-propan-1-one, benzophenone, 1- [4- (2-hydroxyethoxy) -phenyl] -2-hydroxy-2-methyl-1-propan-1-one, 2-methyl -1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, bis (2,6 -Dimethoxybenzoyl) -2,4,4-trimethyl-pentylphosphinoxide, bis (2,4,6-trimethylbenzoyl) -phenylphosphine Oxide, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide, benzyldimethyl ketal, 2,4,6-trimethylbenzophenone, oligo [2-hydroxy-2-methyl-1- (4- (1-methyl Vinyl) phenyl) propanone], 2,4-diethylthioxanthone, p-dimethylaminobenzoic acid isoamyl ester, p-dimethylaminobenzoic acid ethyl ester, and the like, but are not limited thereto.

The titanium oxide used in the ultraviolet curable white ink does not easily transmit ultraviolet rays, but it is preferable to contain 35% or more in the ink in order to ensure concealment. For this reason, the ultraviolet curing rate of the ultraviolet curable white ink tends to be slower than that of a general ultraviolet curable ink containing an organic pigment.
Further, since this white ink is printed by the coating unit, the white ink layer has a thickness of 3 to 5 μm, and the film thickness of the layer is thicker than the ink layer by offset printing.
For this reason, as the photopolymerization initiator, it is preferable to use a photopolymerization initiator that is cured by ultraviolet rays in a long wavelength region of 350 nm or more which is closer to visible light. Moreover, in order to form an ink layer with high whiteness, it is preferable to use a photopolymerization initiator having a light color.

  As a suitable photopolymerization initiator, 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (LUSILIN TPO (trade name) manufactured by BASF Japan Ltd.), bis (2,4,6- Trimethylbenzoyl) -phenylphosphine oxide (Irgacure 819 (trade name) from Ciba Specialty Chemicals), 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropan-1-one (Irgacure 907 (trade name) of Ciba Specialty Chemicals Co., Ltd.).

  The photopolymerization initiator has a content of 1 to 10%, more preferably 3 to 7%, in an ultraviolet curable white ink composed of titanium oxide, an ultraviolet curable resin varnish, an acrylate oligomer and / or an acrylate monomer. Use with a range. If the ratio of the photopolymerization initiator in the white ink exceeds 10%, the excess photopolymerization initiator and the product after radical generation may adversely affect the adhesion and hardness of the white ink, and 1% If it is less than this, the required UV curability cannot be obtained.

  As the polymerization inhibitor used in the active energy ray-curable white ink, a polymerization inhibitor generally used in active energy ray-curable inks such as hydroquinone can be used.

  In addition, the active energy ray-curable white ink includes a leveling agent, an antifoaming agent, a wax, a silane coupling agent, a plasticizer, an infrared absorber, an ultraviolet absorber, a fragrance, a flame retardant and the like as necessary. Additives can be used.

(Water-based white ink)
The water-based white ink dried with warm air in the present invention includes a colorant, a vehicle such as an emulsion resin such as a styrene-acrylic acid resin, a solvent such as an alcohol-based or glycol ether-based solvent and water, and an additive. Air-dried water-based white ink can be used.

As the colorant, a titanium oxide pigment used in general white ink, paint, and recording material is used. Titanium oxide can be either rutile or anatase crystalline, but rutile type is preferable for ensuring the density and concealment of printed matter, and anatase type is preferable for ensuring whiteness. It is preferable that the colorant is contained in an amount sufficient to ensure the concentration and coloring power of the ink, that is, in the range of 25 to 45% in the ink. Further, by substituting some of the colorants with other organic pigments, it is possible to impart a feeling of density and a texture.
As a preferred example, the white ink of the present invention contains at least one selected from the group consisting of PY12, PY13, PR57: 3, PB15: 3, PG7, PV1 and alkali blue toner as a pigment or colorant. 0.05-10 mass parts can be contained with respect to parts. Thereby, a feeling of density and a texture can be imparted to the white ink. In addition, when these colorants are about 0.05 to 5 parts, it is more preferable to use a pigment having light resistance.

  Vehicles such as styrene-acrylic acid resins include styrene- (meth) acrylic acid resins, styrene-maleic acid resins, α-methylstyrene- (meth) acrylic acid resins, (meth) acrylic acid ester resins, acrylic acid ester resins. Such alkali-soluble resins, hydrosol resins, or emulsion resins can be used alone or in admixture of two or more. The resin content is preferably contained in the ink in a proportion of 15 to 55% in order to maintain sufficient wettability with the colorant and fluidity of the ink.

  Examples of the alcohol solvent or glycol ether solvent and water include alcohols such as methanol, ethanol, propyl alcohol, isopropyl alcohol (IPA), ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monobutyl ether, and diethylene glycol. Glycol monoethers such as monomethyl ether, triethylene glycol monomethyl ether, ethylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl ether acetate, or esters thereof, and glycol diethers alone or in combination with two or more solvents Can be used as a solvent with water. The solvent content is preferably included in the ink at a rate of 5 to 15% in order to impart sufficient fluidity to the ink.

  In addition, additives generally used in gravure inks and paints such as colorants, waxes, high boiling point solvents, surfactants and antifoaming agents may be added as necessary.

(Base material)
As the transparent substrate in the present invention, various types of transparent or translucent plastic substrates which have been subjected to surface treatment such as corona discharge or plasma treatment are suitably used. Examples thereof include polyolefin plastics such as polyethylene and polypropylene, polystyrene, and polyester (PET).
In particular, when printing on polyolefin plastic substrates with low polarity, white ink coating that can be printed without water is more effective than printing with offset white ink using fountain solution. It is advantageous with respect to transferability (hiding property) and adhesiveness.
Examples of the base material other than white for surface printing include aluminum vapor-deposited paper and aluminum-laminated paper.

  Examples The present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples without departing from the technical idea of the present invention.

(Preparation of active energy ray-curable white ink of Example 1)
Various materials were blended based on the blending shown in Table 1, and kneaded using a three-roll mill to produce an active energy ray-curable white ink. The numerical values in the table indicate mass%.

(Preparation of active energy ray-curable inks of other examples and comparative examples)
The active energy ray-curable white ink of Example 2 is the same as the active energy ray-curable white ink of Example 1.
The active energy ray-curable white inks of Examples 3 to 9 and Comparative Example 1 were also prepared in the same manner as the active energy ray-curable white ink of Example 1 except that the composition of the raw materials was changed.
The active energy ray-curable white ink of Example 9 is the same as the active energy ray-curable white ink of Example 6.
The water-based white ink dried in warm air of Example 10 was prepared by blending various materials based on the formulation shown in <Composition of Example 10> and kneading using a three-roll mill.
The active energy ray curable white ink of Comparative Example 1 is a general UV curable ink for offset printing.
The reference example is a method in which offset color printing and screen ink printing are performed in separate steps, and is a conventional method.

The blending of these active energy ray-curable white inks is as shown in Tables 1 and 2. The formulation of Example 10 is shown separately.
In Table 1 and Table 2, the pigment is titanium oxide CR58-2 (Ishihara Sangyo Co., Ltd.), the acrylic resin is Beamset 255 (Arakawa Chemical Industries, Ltd.), and the polyester resin is Unidic V. -3211 (manufactured by Dainippon Ink & Chemicals, Inc.), 61X2002 (manufactured by Dainippon Ink & Chemicals, Inc.) was used as the epoxy resin, and Daisoda Dup A (manufactured by Daiso Corporation) was used as the diallyl phthalate resin. .
DPGDA is an abbreviation for dipropylene glycol diacrylate, TPGDA is an abbreviation for tripropylene glycol diacrylate, EOTMPTA is an ethoxy-modified trimethylolpropane triacrylate, and DTMPTA is an abbreviation for ditrimethylolpropane triacrylate.
Irgacure 907 (trade name of Ciba Specialty Chemicals Co., Ltd.) and Lucillin TPO (trade name of BASF Japan Co., Ltd.) are the photopolymerization initiators. As the polymerization inhibitor, tert-butyl hydroquinone was used.

(Evaluation of active energy ray-curable white ink and printed matter)
About the obtained active energy ray hardening-type white ink, the following method performed ink viscosity measurement, sclerosis | hardenability evaluation, hiding property evaluation, and adhesive evaluation. The evaluation results are shown in Tables 1-3.

Example 1
On the printed material, a 300 μm thick corona discharge-treated polypropylene sheet (PP sheet), offset printing was performed using ultraviolet curable ink “Dicure RT-V Black” (manufactured by Dainippon Ink & Chemicals, Inc.). UV (ultraviolet) curing by passing under the irradiation of a UV lamp / metal halide lamp (160 W / cm) × 1 lamp installed in between at a printing speed of 6500 sheets / hour (about 30 m / min) An offset color back print was obtained. The term “between cylinders” means that a lamp is installed between each unit (referred to as a cylinder) when printing each color by a plurality of printing units as in process printing.
Subsequently, an active energy ray-curable white ink having the composition shown in Example 1 in Table 1 was applied onto the printed matter by an in-line roll coater, and UV lamp / metal halide lamp (160 W / cm) manufactured by Eye Graphics Co., Ltd. × By passing 6500 sheets / hour under irradiation of 3 lamps, a printed matter for evaluation of offset color + white ink back printing was obtained. The following items a to d were evaluated for the ink used and the prepared printed matter for evaluation.

(A. Ink viscosity)
The ink viscosity was measured with a BM type viscometer manufactured by Tokyo Keiki Co., Ltd. at a rotation speed of 60 rpm and a temperature of 25 ° C. In Table 1, the fluidity was evaluated according to the following criteria. An ink having a viscosity of 5 poises or less can be said to be an ink having excellent coating suitability. If it is 15 poises or less, it is sufficient for practical use.
5: The viscosity is 5 poises or less.
4. The viscosity is 5 poise or more and 10 poise or less.
3. The viscosity is 10 poise or more and 15 poise or less.
2. Viscosity is 15 poise or more and 20 poise or more.
1 ... The viscosity is 20 poise or more.

(B. Curability measurement)
Using the printed matter for evaluation, the surface of the printed material was evaluated by the tackiness when touched with a finger and the smoothness of the surface. In Table 1, the curability was evaluated according to the following criteria. A rating of 3 or higher is a practically sufficient level.
5: There is no tackiness and the surface is smooth.
4 ... There is no tackiness at all, but the surface smoothness is slightly worse.
3 ... There is no tackiness, but there is no surface roughness.
2 ... Slight tackiness and no surface roughness.
1 ... There is a lot of tackiness and the surface is sticky.

(C. Adhesive evaluation)
A peel test was performed using a printed product for evaluation using a cellophane adhesive tape having a width of 18 mm (hereinafter simply referred to as an adhesive tape) manufactured by Nichiban Co., Ltd., and ink removal on the cellophane adhesive tape was evaluated. Judgment criteria are as follows. A rating of 3 or higher is a practically sufficient level.
5: No ink is taken on the adhesive tape.
4 ... Less than 20% of ink is removed from the adhesive tape.
3 ... 20% or more and less than 40% of ink is removed from the adhesive tape.
2 ... 40% or more and less than 60% of ink is observed on the adhesive tape.
1 ... 60% or more of ink was removed from the adhesive tape.

(D. Evaluation of concealment)
The hiding property of the white ink in the evaluation printed matter was determined by visually observing the degree of transparency of the characters placed under the evaluation printed matter and the transparency of the characters. A rating of 3 or higher is a practically sufficient level.
5 ... Characters are not transparent at all.
4 ... There is a transparent character, but cannot be read.
3 ... There is a translucency of the character and can be read a little.
2 ... The characters are transparent and can be read roughly.
1 ... The characters are transparent and can be read clearly.

(Example 2)
The obtained active energy ray-curable white ink was coated on a 300 μm thick corona discharge treated polypropylene sheet (PP sheet) using a roll coater installed in front of the offset printing cylinder. UV curing was performed by passing 6500 sheets / hour (about 30 m / min) under irradiation of a UV lamp / metal halide lamp (160 W / cm) × 1 lamp manufactured by Graphics Co., Ltd. to obtain a white ink coated printed matter.
On this white ink-coated printed material, UV printing ink “Dicure RT-V Black” (manufactured by Dainippon Ink & Chemicals, Inc.) was subsequently offset printed, and a UV lamp / metal halide lamp (made by Eye Graphics Co., Ltd.) 160W / cm) × 3 lamps were passed through at 6500 sheets / hour (about 30 m / min) for UV curing to produce a printed surface print for evaluation. About the used ink and produced printed matter, it evaluated similarly about the item of said ad.

(Example 3)
A back print was prepared and evaluated in the same manner as in Example 1 except that an active energy ray-curable white ink using a polyester resin as a resin varnish was used.

Example 4
A back printed material was prepared and evaluated in the same manner as in Example 1 except that an active energy ray-curable white ink using an epoxy resin was used as the resin varnish.

(Example 5)
A back print was prepared and evaluated in the same manner as in Example 1 except that an active energy ray-curable white ink using diallyl phthalate resin as the resin varnish was used.

(Example 6)
A back print was prepared and evaluated in the same manner as in Example 1 except that an active energy ray-curable white ink using tripropylene glycol diacrylate (TPGDA) as a monomer was used.

(Example 7)
A back print was prepared and evaluated in the same manner as in Example 1 except that an active energy ray-curable white ink using ethoxy-modified trimethylolpropane triacrylate (EOTMPTA) as a monomer was used.

(Example 8)
A back print was prepared and evaluated in the same manner as in Example 1 except that an active energy ray-curable white ink using ditrimethylolpropane tetraacrylate (DTMPTA) as a monomer was used.

Example 9
A surface printed material was prepared and evaluated under the same conditions as in Example 2 except that the active energy ray-curable white ink of Example 6 was used.

(Example 10)
The formulation is shown in <Formulation of Example 10>. As the pigment, Sanka Titanium JR809 (Taika Co., Ltd.) was used as the rutile type titanium oxide, and Titanium White A220 (Ishihara Sangyo Co., Ltd.) was used as the anatase type titanium oxide.
Further, Shonkrill 7001 (Johnson Polymer Co., Ltd.) and John Krill 352D (Johnson Polymer Co., Ltd.) were used as the styrene-acrylic emulsion resin, and Jonkrill 60 (Johnson Polymer) was used as the water-soluble resin. In addition to these, other raw materials shown in the formulation were mixed to prepare a white ink of Example 10 which is a warm air drying type. Prior to coating, the viscosity was readjusted to about 18 seconds with Zahn Cup # 4 using water.
UV graphics curable ink "Dicure RT-V Black" (Dainippon Ink Chemical Co., Ltd.) is offset printed on a 300 µm thick corona discharge-treated polypropylene sheet (PP sheet) to be printed. Curing was performed with a torso UV lamp / metal halide lamp (160 W / cm) × 1 lamp.
Subsequently, the hot air-dried water-based white ink of Example 10 was applied onto the printed matter with an in-line roll coater and irradiated with UV lamp / metal halide lamp (160 W / cm) × 3 lamps manufactured by Eye Graphics Co., Ltd. Was passed through 6500 sheets / hour to completely cure the underlying UV-curing black ink and dry the warm water-based white ink simultaneously to obtain a printed material for evaluation of the back print. About the used ink and produced printed matter, it evaluated similarly about the item of said ad.

<Formulation of Example 10>
Sanka Titanium JR809 ... 20 parts,
Titanium white A220 ... 13 parts,
Jonkrill 7001 ... 30 copies,
Jonkrill 352D ... 10 parts,
John Krill 60 ... 12 copies,
Polyethylene wax ... 2 parts,
Anionic surfactant ... 1 part,
Diethylene glycol ether solvent ... 2 parts
IPA 3 parts,
Water ... 7 parts,
Silicone-based antifoaming agent: 0.5 part.
(Total of formulation of Example 10: 100.5 parts)

(Comparative Example 1)
On the printed material, a 300 μm thick corona discharge-treated polypropylene sheet (PP sheet), offset printing was performed using ultraviolet curable ink “Dicure RT-V Black” (manufactured by Dainippon Ink & Chemicals, Inc.). UV (ultraviolet) curing by passing under the irradiation of a UV lamp / metal halide lamp (160 W / cm) × 1 lamp installed in between at a printing speed of 6500 sheets / hour (about 30 m / min) Subsequently, the active energy ray-curable white ink of Comparative Example 1 was printed, and a printing speed of 6,500 sheets / hour (about 30 m) under irradiation of UV lamp / metal halide lamp (160 W / cm) × 3 lamps manufactured by Eye Graphics Co., Ltd. / Min), UV-curing was performed, and a printed material for evaluation of back printing was prepared.
About the used ink and the produced printed matter, it evaluated similarly to what was shown to description of the said Example 1 about the item of said ad.
Since white ink is offset printing, the film thickness is small and the hiding property is not good.

(Reference example)
On the printed sheet of 300 μm thick corona discharge-treated PP sheet, offset printing was performed using UV curable ink “Dicure RT-V Black” (manufactured by Dainippon Ink & Chemicals, Inc.). UV curing was conducted by passing 6500 sheets / hour (about 30 m / min) under irradiation of a UV lamp / metal halide lamp (160 W / cm) × 3 lamps.
After that, silk screen printing was performed using a UV screen type ink “Dicure SSD F27 White” (manufactured by Dainippon Ink & Chemicals, Inc.) using another silk screen printing machine, and UV lamps / metal halide lamps manufactured by Eye Graphics Co., Ltd. UV curing was carried out by passing it through 6160 sheets / hour (about 30 m / min) under irradiation of (160 W / cm) × 3 lamps.
Although the evaluation of this reference example is at a usable level, since it requires two steps offline, there are drawbacks that it takes time and productivity is low.

(Table 3: Evaluation of Example 10 and Comparative Example 2)

The printed matter of the present invention is a back-printed printed matter and a surface-printed printed matter having a white ink layer that is uniform and excellent in hiding properties, and can obtain a high-quality image. In addition, the conventional screen printing and offset printing are used in combination, and the time and cost are improved as compared with the case where the white ink coating and the color ink printing are performed in two separate steps.

Claims (7)

  A back-printed product in which a printing layer by offset printing is provided on a transparent substrate, and white ink is coated on the printing layer using a coater.   A surface printed matter in which a white ink is applied to a transparent substrate or a substrate other than white using a coater, and a printing layer is formed on the white ink layer by offset printing.   The printed matter according to claim 1, wherein the white ink is an active energy ray-curable ink.   The printed matter according to claim 1, wherein the white ink is a hot-air drying type ink.   3. The method according to claim 1, wherein the step of providing a printing layer by offset printing on the substrate and the step of providing a white ink layer by a coater are performed in one step by an offset printing machine having a coater unit. A method for producing a printed material according to 1.   The printed matter according to claim 3, wherein the active energy ray-curable ink contains a styrene-acrylic acid copolymer resin and dipropylene glycol diacrylate as a vehicle. The white ink contains titanium oxide, and at least one selected from the group consisting of PY12, PY13, PR57: 3, PB15: 3, PG7, PV1 and alkali blue toner as a pigment or a colorant. The printed matter according to claim 3, which contains 0.05 to 10 parts by mass with respect to 100 parts by mass.