JP6121136B2 - Gravure offset printing ink - Google Patents

Description

  The present invention relates to an ink for gravure offset printing.

  A method of printing a predetermined pattern on the surface of various articles using a liquid, paste-like ink is useful for manufacturing various industrial products. In the case of repeatedly manufacturing articles having the same pattern, the effect of suppressing the manufacturing cost is great. This is a particularly excellent method when the same pattern is repeatedly formed on a continuous sheet-like article.

  In recent years, in the electronics field, various articles have been manufactured by a printing technique. For example, the application range of the printing technique is wide, such as an electronic circuit formed on a film, various display panels as an information display device, a solar battery panel and its electrodes. Under such circumstances, a method for further improving the printing resolution and printing a finer pattern is strongly demanded.

  Ink-jet printing technology has progressed over high-resolution printing and fine pattern printing, but still, for example, printing independent patterns with an average maximum dot diameter of 20 μm or less, or fine lines with a line width of 20 μm or less It is difficult to print. As in the case of using a printing plate, ink droplets that have landed on the substrate spread on the surface, and adjacent dots are connected. In order to prevent this, even if the viscosity and surface tension of the ink are adjusted, the allowable range is extremely small in the case of inkjet printing.

  Under such circumstances, gravure printing, particularly gravure offset printing, is suitably used for printing fine patterns.

  Patent Document 1 discloses an electrode composition for offset printing comprising a conductive material, an organic binder, and a glass frit in addition to a solvent, and the glass transition temperature of the organic binder is in the range of −50 to −5 ° C. Yes. Thereby, only a necessary part is printed only by printing, drying, and baking processes, so that a fine electrode pattern can be reproducibly formed on the substrate without loss of expensive material.

Special table 2011-503240 gazette

  However, the method described in Patent Document 1 has a problem in that the glass transition temperature of the organic binder is as low as −50 to −5 ° C., so that the adhesion to the substrate and the blocking resistance are lowered. In particular, when other processing is required after the pattern is printed, the pattern may be peeled off due to the low adhesion.

  On the other hand, it is conceivable to use a resin having a high glass transition temperature as an ink composition when trying to improve adhesion, but in the case of gravure offset printing, there is a problem that transferability and printability deteriorate. .

  The ink for gravure offset printing of the present invention solves the above-described problems, and can obtain a printed matter having excellent transferability and printability, high adhesion to a substrate to be printed, and good blocking resistance. It is an ink that can be used.

That is, the gravure offset printing ink of the present invention comprises a polyester-based thermoplastic resin having a glass transition temperature (Tg) of 45 to 90 ° C., palladium metal fine particles supported on a porous carrier , acryloyl group or methacryloyl group. It is the ink for gravure offset printing containing the photocurable resin which has. The content of the photocurable resin is preferably 10 to 200% with respect to the weight of the thermoplastic resin.

  ADVANTAGE OF THE INVENTION According to this invention, the ink for gravure offset printing which can obtain the printed matter which is excellent in transferability and printability, has high adhesiveness to a to-be-printed base material, and has favorable blocking resistance can be provided.

It is a schematic diagram which shows a general gravure offset printing apparatus.

  The thermoplastic resin used in the gravure offset printing ink of the present invention may have a glass transition temperature (Tg) of 45 to 90 ° C., and examples thereof include polyester resins, polyamide resins, polyurethane resins, and acrylic resins. Of these, polyester resins are preferred because of their versatility and low cost.

  As the photocurable resin used in the present invention, a monomer, oligomer, or polymer having a photopolymerizable functional group that is crosslinked by a photopolymerization initiator can be used. Examples of the photopolymerizable functional group include an ethylenically unsaturated bond. Especially, it is preferable that the acryloyl group and the methacryloyl group are included.

Examples of the monomer of the photocurable resin include isoamyl acrylate, lauryl acrylate, stearyl acrylate, ethoxy-diethylene glycol acrylate, methoxy-triethylene glycol acrylate, 2-ethylhexyl-diglycol acrylate, methoxy-polyethylene glycol acrylate, and methoxydipropylene. Glucol acrylate, phenoxyethyl acrylate, phenoxydiethylene glycol acrylate, phenoxy-polyethylene glycol acrylate, tetrahydrofurfuryl acrylate, isobornyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, 2-hydroxybutyl acrylate, 2-hydroxy- 3-phenoxypropyl aqua Rate, 3-acryloyloxyethyl-succinic acid, 2-acryloyloxyethyl hexahydrophthalic acid, 2-acryloyloxyethyl-phthalic acid, 2-acryloyloxyethyl-2-hydroxyethyl-phthalic acid, neopentyl Glycol-acrylic acid-benzoic acid ester, 2-acryloyloxyethyl acid phosphate, triethylene glycol diacrylate, polytetramethylene glycol diacrylate, neopentyl glycol diacrylate, 3-methyl-1.5 pentanediol diacrylate 1.6-hexanediol diacrylate, 1.9-nonanediol diacrylate, dimethylol-tricyclodecane diacrylate, 2-hydroxy-3-acryloyloxypropyl methacrylate, trimethylol B bread triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate, and the like.

Examples of photocurable resin oligomers or polymers include vinyl polymers such as (meth) acrylic acid (co) polymers, maleic acid (co) polymers, polyethylene oxide, polyvinylpyrrolidone, polyamides, polyurethanes, polyethers, Examples thereof include polymers having an ethylenic double bond in the side chain such as polyester. These monomers, oligomers and polymers may be used alone or in combination of two or more.

The photocurable resin preferably has a number average molecular weight of 200 to 10,000, more preferably 300 to 5,000. If it is less than 200, the print transferability tends to be reduced, and if it exceeds 10,000, the viscosity after ink adjustment becomes high, and it tends to be difficult to scrape off the doctor for offset printing.

In this invention, a photoinitiator can be used by 1 type (s) or 2 or more types, It is preferable to contain 1-20% with respect to the weight of a photocurable resin, especially 5-15%. Examples of the photopolymerization initiator include acetophenone-based, benzoin-based, benzophenone-based, and thioxanthone-based initiators.

Examples of the acetophenone polymerization initiator include acetophenone, p- (tert-butyl) -1 ′, 1 ′, 1′-trichloroacetophenone, chloroacetophenone, 2 ′, 2′-diethoxyacetophenone, hydroxyacetophenone, 2, Examples include 2-dimethoxy-2′-phenylacetophenone, 2-aminoacetophenone, dialkylaminoacetophenone and the like. Benzoin-based polymerization initiators include benzyl, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin isobutyl ether, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenyl-2-methyl Propan-1-one, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, benzyldimethyl ketal and the like can be mentioned. Examples of the benzophenone polymerization initiator include benzophenone, benzoylbenzoic acid, methyl benzoylbenzoate, methyl-o-benzoylbenzoate, 4-phenylbenzophenone, hydroxybenzophenone, hydroxypropylbenzophenone, acrylic benzophenone, 4,4′-bis (dimethylamino). ) Benzophenone and the like.
Examples of the thioxanthone polymerization initiator include thioxanthone, 2-chlorothioxanthone, 2-methylthioxanthone, diethylthioxanthone, and dimethylthioxanthone.

  As the metal fine particles, copper, gold, silver, platinum, palladium, iron, cobalt, nickel and the like can be used. These can be used in the form of simple metals, salts or oxides. These metal fine particles may be supported on a carrier. As the carrier, alumina gel, silica gel, titanium oxide, aluminum oxide, zirconium oxide, silicon dioxide and the like are used. The carrier is preferably porous in order to improve the amount of metal fine particles supported. These metal fine particles themselves act as conductive fine particles and impart conductivity to the printed pattern. Further, a metal film can be formed by electroplating or electroless plating using these metal fine particles as a nucleus.

  The ink for gravure offset printing of the present invention may contain a solvent for the purpose of adjusting the viscosity during printing. The solvent can be appropriately selected according to other functional materials contained in the ink. Common solvents include alcohols such as methanol, ethanol, n-propyl alcohol and isopropyl alcohol, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone and isophorone, aromatic hydrocarbons such as toluene and xylene, Propylene glycol monomethyl ether, propylene glycol monomethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether, diethylene glycol monoethyl ether acetate, diethylene glycol monobutyl acetate, 3-methoxybutanol, 3-methoxybutyl acetate, 1,3-butylene glycol , Dipropylene glycol methyl ether, tripropylene glycol Chill ether, tripropylene glycol methyl ether, propylene glycol n-propyl ether, dipropylene glycol n-propyl ether, tripropylene glycol n-butyl ether, dipropylene glycol methyl ether acetate, propylene glycol acetate, 1,3-butylene glycol diacetate, Glycols and derivatives thereof such as 1,4-butanediol diacetate, 1,6-hexanediol diacetate, dipropylene glycol dimethyl ether, dipropylene glycol methyl-n-propyl ether, glycerin and derivatives thereof such as glycerin and triacetin, Methyl acetate, ethyl acetate, isopropyl acetate, n-propyl acetate, butyl acetate, cyclohexane Acetic acid esters such as cyclohexanol acetate, .gamma.-butyrolactone, N- methyl pyrrolidone, N, N- dimethylformamide, dimethyl sulfoxide, dimethyl acetamide, dimethyl carbonate, dioxane, tetrahydrofuran, solvent naphtha, and the like. One of these solvents may be used, or a mixture of a plurality of kinds may be used.

  Examples of the substrate to be printed used in the present invention include glass, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyethylene terephthalate-isophthalate copolymer, terephthalic acid-cyclohexanedimethanol-ethylene glycol copolymer, and the like. Polyester resins such as polyester resins, polyamide resins such as nylon 6, polyolefin resins such as polypropylene and polymethylpentene, acrylic resins such as polyacrylate, polymethacrylate and polymethyl methacrylate, styrene resins such as ABS resin, triacetyl Examples thereof include cellulose-based resins such as cellulose, imide-based resins, polycarbonate, and glass. Of these, polyester films such as polyethylene terephthalate and polyethylene naphthalate are suitable for use because of their high versatility and low cost, and polyethylene terephthalate films are particularly suitable. The substrate to be printed is used as a sheet, a film, or a plate made of these materials.

  Although the thickness of a base material is not specifically limited, Usually, it is about 10 micrometers-about 2000 micrometers, Preferably it is the range of about 50 micrometers-1000 micrometers. If the thickness is too thin, the strength is too low, and if it is too thick, it tends to be impractical in terms of weight and cost, and the suitability for continuous printing also decreases.

FIG. 1 is a schematic diagram showing a general gravure offset printing apparatus. In the gravure offset printing method, ink is supplied from the ink pan 6 onto the printing plate 5, the excess ink on the printing plate 5 is scraped off by the doctor blade 4, and filled into the recesses formed on the printing plate 5. The transferred ink is transferred onto the rotating blanket 3 in contact with the printing plate 5, and then the ink transferred to the blanket is printed while pressing the impression cylinder 2 against the substrate 1.

The running speed of the substrate during printing is preferably 5 to 100 m / min, and more preferably 10 to 50 m / min. With such a traveling speed, fine wiring can be printed with high accuracy without blurring or blurring.

The printing plate used in the present invention can be a general printing plate. For example, a printing plate made of metal such as copper or iron, resin, or ceramic is used. Moreover, what formed the film which consists of chromium, a ceramic, diamond-like carbon, etc. on the surface may be used. The printing plate is engraved with a printing pattern by an etching method or a laser engraving method, and this pattern is filled with ink. The printing plate is a flat plate or a roll. The plate-like printing plate is suitable for the purpose of producing a relatively small printed material or a small amount of printed material, and the roll-shaped printing plate is useful for producing a large printed material or a large amount of printed material continuously.

The blanket may have a multilayer structure in which a surface layer made of a resin that receives ink filled in the printing plate and a cushion layer laminated on the side of the surface layer opposite to the surface that receives ink. Furthermore, the structure which laminated | stacked reinforcement layers, such as a fabric for improving an intensity | strength, and a resin film, may be sufficient. Such a blanket may be used by being attached to a base member that supports the blanket. The base member is preferably made of a material that hardly undergoes deformation due to stress, and is made of metal, resin, ceramic, or the like. In addition, the shape of the base member may be a flat plate shape, a roll shape, or the like, and is configured to cover the surface of the base member with a blanket.

The surface layer of the blanket of the present invention is preferably made of a resin and particularly elastic rubber. Examples of the material for the surface layer of the blanket include nitrile rubber, hydrogenated nitrile rubber, fluorine rubber, silicone rubber, urethane rubber, ethylene propylene rubber, chloroprene rubber, styrene butadiene rubber, butadiene rubber, and mixtures thereof. Of these, silicone rubber is preferably used because of its high solvent resistance and low wet tension and a wide range of solvent options.

The substrate on which the ink has been printed becomes solid after being dried and then irradiated with ultraviolet rays (UV). Examples of means for drying include air drying, hot air drying, and heat drying using an infrared furnace. The drying method can be appropriately selected depending on the heat resistance of the substrate to be printed and the drying speed of the solvent. As a light source for irradiating with ultraviolet rays, a high pressure mercury lamp, a low pressure mercury lamp, a xenon lamp, a metal halide lamp or the like can be appropriately selected and used.

Moreover, electroconductivity can be provided by plating after ultraviolet irradiation. There are electroless plating and electroplating as plating methods. Examples of the metal to be plated include copper, nickel, tin, zinc, and gold, and alloys thereof can be used, and copper is preferable from the viewpoint of conductivity and cost.

An example of the electroless plating treatment of the printed substrate will be given. When forming a conductive layer made of copper, a water-soluble copper salt such as copper sulfate 1 to 100 g / L, particularly 5 to 50 g / L, a reducing agent such as formaldehyde 0.5 to 10 g / L, particularly 1 to 5 g / L. A transparent substrate having a plating catalyst layer and the like in a solution containing complexing agents such as EDTA, 20 to 100 g / L, particularly 30 to 70 g / L, and adjusted to pH 12 to 13.5, particularly 12.5 to 13 A method of immersing at 50 to 90 ° C. for 30 seconds to 60 minutes can be employed. In addition, you may add 1-50 mg / L of bipyridine, especially 2-10 mg / L as a stabilizer of a liquid. Moreover, when there is conduction in the printing substrate, electroplating is possible.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to these Examples.

Example 1
20 parts by weight of a thermoplastic resin having a glass transition temperature Tg of 47 ° C., 10 parts by weight of titanium oxide porous catalyst particles containing palladium metal, 70 parts by weight of a cyclohexanone solvent, and 20 parts by weight of a photocurable resin having a molecular weight of about 300 ( The ink was prepared using 100% of the weight of the thermoplastic resin) and 2 parts by weight of the photopolymerization initiator.

The base material was a 100 μm-thick easy-adhesion-treated polyester film (Diafoil T680E100U76, manufactured by Mitsubishi Resin Co., Ltd.), and the printing surface was an easy-adhesion surface.

  As a printing plate for gravure offset printing, a lithographic plate which was formed by patterning on a copper plate having a thickness of 100 μm by an etching method and then was plated with chromium (5 μm thickness) was used. The pattern after chromium plating had a grid of concave lines, a line width of 30 μm, a depth of 10 μm, and a pitch of 200 μm.

  The blanket is coated with a two-part silicone RTV rubber (KE-12, manufactured by Shin-Etsu Chemical Co., Ltd.) with a bar coater on a 100 μm thick polyester film (Diafoil T600E100, manufactured by Mitsubishi Plastics). A product prepared by leaving it to stand for 24 hours at room temperature was used.

  In gravure offset printing, the ink prepared above was applied to a printing plate, scraped off with a doctor blade, the blanket was overlaid on the printing plate, and ink was applied from the printing plate to the blanket. Ten seconds later, the substrate was placed on a blanket and the entire surface was pressed with a rubber roller to complete printing. Printing was performed with the atmospheric temperature during the printing operation being 25 ° C. and the plate surface temperature of the printing plate being adjusted to 25 ° C.

The obtained printed product was dried at 80 ° C. for several minutes, and then irradiated with ultraviolet rays (UV) with an integrated light amount of 1000 mJ / cm ² in an air atmosphere.

Then, it immersed in the electroless copper plating liquid of 50 degreeC of liquid temperature, and electroless copper plating was performed for 15 minutes. The obtained electroless plating thickness was 2 μm. The composition of the electroless plating solution is shown below.

(Electroless plating solution)
Complexing agent (EDP-300, manufactured by ADEKA) 40 g / L
CuCl ₂ 5g / L
NaOH 10g / L
Bipyridine 5mg / L
Formaldehyde 5g / L

In the process from printing to electroless plating, transferability, printability, and adhesion were evaluated. Transferability refers to the ease of ink transfer from the blanket to the substrate in the gravure offset printing process. After printing, the surface of the blanket is observed, and the ink residue does not remain on the blanket. The transfer was (◯), the residue with some residues remaining and printing unevenness (Δ), and the residue with most residues (×). In addition, when transferability is x, the subsequent printability and adhesion cannot be evaluated (-). For printability, the printed product is observed with a microscope (manufactured by Keyence Corp.). If there is no disconnection (○), if there is disconnection, it is determined that conduction is possible in the subsequent plating process (△). (X) was determined to be non-conductive in the subsequent plating step. The adhesion was evaluated according to the tape test method of the peeling test method according to JIS H8504 after electroless plating. The results are shown in Table 1.

Moreover, blocking resistance was evaluated as a method of evaluating the handleability of printed products. When the printed product is rolled up, the degree to which the resin film containing the metal of the printed product peels off and moves to the back surface of the printed product is evaluated. The printed product was cut into a size of 30 mm × 30 mm, and a polyethylene terephthalate film was superimposed on the surface on which the metal-containing resin coating was formed, and was left to stand for 1 hour in a 50 ° C. atmosphere under a load of 80 g / cm ² . Thereafter, the polyethylene terephthalate film was peeled off, the state of the photocurable resin film was observed, and the determination was made according to the following criteria. When the polyethylene terephthalate film was peeled off, the resin film containing the metal had no damage (peeling) (O), and when the polyethylene terephthalate film was peeled off, the metal resin film was damaged (peeled) The thing was set as (x). In addition, when transferability is x, blocking resistance cannot be evaluated (-).
The results are shown in Table 1.

(Examples 2 to 14, Comparative Examples 1 and 2)
The same procedure as in Example 1 was conducted except that the Tg of the thermoplastic resin of the ink, the type and content ratio of the photocurable resin, and the ratio of addition of the photopolymerization initiator were the same as those shown in Tables 1 and 2. .

(Comparative Examples 3 and 4)
Instead of a photocurable resin and a photopolymerization initiator, diethyl phthalate (Comparative Example 3) and dioctyl phthalate (Comparative Example 4), which are used as general plasticizers, are used without irradiating UV to the printed product. The same operation as in Comparative Example 1 was performed except that the electroless plating was performed.

From Table 1 and Table 2, by limiting the range of Tg of the thermoplastic resin and containing an appropriate amount of photocurable resin, the transferability, printability and blocking resistance of gravure offset printing are good, and adhesion after plating It can be seen that the properties are also good. In particular, when the molecular weight of the photocurable resin is 300 or more, transferability, printability, adhesion, and blocking resistance are even better.

DESCRIPTION OF SYMBOLS 1 Substrate to be printed 2 Impression cylinder 3 Blanket 4 Doctor blade 5 Printing plate 6 Ink pan

Claims (2)

Gravure offset printing comprising a polyester thermoplastic resin having a glass transition temperature (Tg) of 45 to 90 ° C, palladium metal fine particles supported on a porous carrier, and a photocurable resin having an acryloyl group or a methacryloyl group. ink. The ink for gravure offset printing according to claim 1, wherein the content of the photocurable resin is 10 to 200% based on the weight of the thermoplastic resin.

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