JP3003161B2 - Gloss processing method for lithographic printing - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for processing gloss of a lithographic printed matter, and more particularly, to glossiness, adhesiveness of cellophane adhesive tape, folding property and gluing suitability on the surface of the lithographic printed matter. And a method for forming a clear coating film having excellent secondary workability such as friction resistance.

[Prior Art] Switching to a UV-curable gloss varnish has been carried out in order to reduce work environment pollution or increase work efficiency by discharging organic solvents contained in oily gloss varnish.

When UV-curable gloss varnish is applied to the underlying printing layer composed of UV-curable ink, it can be made to have the same composition as the underlying ink, without worrying about adhesion to the printing layer,
Further, there is an advantage that the balance adjustment of the gloss and the secondary workability of the printed matter becomes easy.

[Problems to be Solved by the Invention] However, limiting the base ink to the ultraviolet curable ink is not preferable because the range of the target printed matter for glossy varnish finishing is limited. If the base ink is an oil-based ink, the target range is expanded, but the method of blending and preparing the clear paint becomes important. If the clear paint for the ultraviolet-curable ink is left as it is, the adhesion is insufficient. On the other hand, if the adhesion is improved, the gloss will decrease,
Alternatively, problems such as insufficient friction resistance occur. Also, if you improve the gloss, adhesion and bendability,
There is a problem that the friction resistance becomes insufficient. If an additive such as silicone is used in the formulation of the clear paint, there arises a problem that the suitability for pasting is deteriorated. In short, it is very difficult to satisfy all the important required qualities of clear coating and finishing, and this has been a major problem in developing an ultraviolet curable clear coating.

The problem to be solved by the present invention is a method of forming a clear coating film having excellent secondary workability such as gloss, adhesive property of cellophane adhesive tape, bending property, proper gluing, and abrasion resistance on the surface of a lithographic print. Is to provide.

Means for Solving the Problems The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and as a result, by adding an alkyd resin to a conventional ultraviolet-curable resin composition, gloss, adhesiveness, Found that a clear coating film with excellent secondary workability can be formed,
The present invention has been completed.

That is, in order to solve the above-mentioned problems, the present invention provides a gloss processing method for a lithographic print, which is obtained by coating and curing an ultraviolet-curable resin composition containing an alkyd resin on the lithographic print.

The alkyd resin used in the present invention is obtained by reacting a polyhydric alcohol, a dibasic acid and an oil or fat by a known method. Its solid content acid value is usually 30
The following are appropriate:

Examples of the polyhydric alcohol used as a raw material of the alkyd resin include glycerin, trimethylolpropane, pentaerythritol, ethylene glycol, propylene glycol and the like.

Examples of the dibasic acid used as a raw material of the alkyd resin include (phthalic anhydride), isophthalic acid, terephthalic acid,
(Anhydride) trimellitic acid, adipic acid, (anhydride) maleic acid, fumaric acid and the like.

The oils and fats used as raw materials of the alkyd resin include linseed oil, safflower oil, tung oil, dehydrated castor oil, soybean oil, cottonseed oil, rice bran oil and their fatty acids. When these use ratios are represented by oil length, they are usually 50 to 90%, preferably
60-80%. When the oil length exceeds 90%, the friction resistance is reduced, and when the oil length is less than 50%, the adhesiveness and gloss tend to be reduced, so that it is not preferable.

The molecular weight of the alkyd resin used in the present invention is 4,000 or more, preferably 4,000 to 20,000. When the molecular weight is less than 4000, the friction resistance and the scratch resistance tend to be lowered, which is not preferable.

The amount of the alkyd resin in the ultraviolet-curable resin composition used in the present invention is usually 2 to 50% by weight, preferably 5 to 50% by weight.
~ 40% by weight. 50% by weight of alkyd resin used
If the amount exceeds the above range, the ultraviolet curability is remarkably deteriorated, which tends to cause backing during printing. When the use amount of the alkyd resin is less than 2%, it is not preferable that the balance of gloss, adhesion to the base, and secondary workability tends to be difficult when the base is oil-based ink.

The ultraviolet-curable resin composition used in the present invention contains, in addition to the alkyd resin, a radically polymerizable monomer and a photopolymerization initiator, and, if necessary, may further contain a radically polymerizable oligomer. .

As the radically polymerizable monomer, oligomer and photopolymerization initiator used in the present invention, conventionally known materials used in UV-curable inks or paints can be used without any particular limitation.

Among the radical polymerizable monomers, examples of the monofunctional monomer include lauryl (meth) acrylate, stearyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl (meth) acrylate, and cyclohexyl (meth). Acrylate, dicyclopentanyl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, phenyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, phenoxytetraethylene glycol (meth) Acrylate, nonylphenoxyethyl (meth) acrylate, nonylphenoxytetraethylene glycol (meth) acrylate, methoxydiethyl Glycol (meth) acrylate, ethoxy diethylene glycol (meth) acrylate, butoxyethyl (meth) acrylate, butoxy triethylene glycol (meth) acrylate, 2
-Ethylhexyl polyethylene glycol (meth) acrylate, nonylphenyl polypropylene glycol (meth) acrylate, methoxydipropylene glycol (meth) acrylate, glycidyl (meth) acrylate, N-vinylpyrrolidone, 2-hydroxyethyl (meth) acrylate, 2-hydroxy Propyl (meth) acrylate, glycerol (meth) acrylate, polyethylene glycol (meth) acrylate, polypropylene glycol (meth) acrylate, epichlorohydrin-modified butyl (meth) acrylate, epichlorohydrin-modified phenoxy (meth) acrylate, ethylene oxide-modified phthalic acid (meth) Acrylate,
Ethylene oxide-modified succinic acid (meth) acrylate, caprolactone-modified 2-hydroxyethyl (meth)
Acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-diethylaminoethyl (meth) acrylate, ethylene oxide-modified phosphoric acid (meth) acrylate, and the like can be given.

Examples of the bifunctional monomer include, for example, 1,3-butylene glycol di (meth) acrylate, 1,4-butylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, and 1,6-hexane glycol. Di (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, ethylene oxide-modified neopentyl glycol di (meth) acrylate, propylene oxide-modified neopentyl glycol di ( Meth) acrylates,
Bisphenol A di (meth) acrylate, ethylene oxide modified bisphenol A di (meth) acrylate, epichlorohydrin modified bisphenol A di (meth) acrylate, ethylene oxide modified bisphenol S di (meth) acrylate, allyl di (meth) acrylate, hydroxypivalic acid ester Neopentyl glycol diacrylate, caprolactone-modified hydroxypivalic acid ester neopentyl glycol diacrylate, neopentyl glycol-modified trimethylolpropane di (meth) acrylate, stearyl acid-modified pentaerythritol di (meth) acrylate, dicyclopentenyl acrylate, ethylene oxide-modified Examples include dicyclopentenyl (meth) acrylate and diacrylated isocyanurate. It is.

Examples of the trifunctional monomer include, for example, trimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, and propylene oxide-modified trimethylolpropane tri (meth) acrylate. Acrylate, epichlorohydrin-modified trimethylolpropane tri (meth) acrylate, epichlorohydrin-modified glycerol tri (meth) acrylate, tris (acryloxyethyl) isocyanurate,
Tris (methacrylate ethyl) isocyanurate and the like can be mentioned.

Further, as the polyfunctional acrylate, for example, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol monohydroxypenta (meth) acrylate, alkyl-modified dipentaerythritol pentaacrylate, dipentaerythritol hexa (Meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, and the like.

Examples of the oligomer include bisphenol A type,
Novolak type, polyhydric alcohol type, polybasic acid type, polybutadiene type epoxy acrylate, polyester type,
Polyether type urethane acrylate and the like can be mentioned.

Further, if necessary, an unsaturated polyester using α, β-unsaturated dicarboxylic acid or an oligomer of diallyl terephthalate may be added to the ultraviolet-curable resin composition used in the present invention.

The amount of the radical polymerizable monomer and oligomer used in the ultraviolet-curable resin composition used in the present invention is usually preferably in the range of 40 to 85% by weight and 0 to 20% by weight, respectively.

Examples of the photopolymerization initiator include hydrogen abstraction types such as benzyl, benzophenone, Michler's ketone, 2-chlorothioxanthone and 2,4-diethylthioxanthone; benzoin ethyl ether, diethoxyacetophenone, benzyl methyl ketal, hydroxycyclohexyl phenyl ketone, Examples thereof include photocleavable types such as -hydroxy-2-methylphenyl ketone. These photopolymerization initiators can be used alone or in combination of two or more.

The amount of the photopolymerization initiator used in the ultraviolet-curable resin composition used in the present invention is usually preferably in the range of 5 to 20% by weight.

It is also possible to use a photosensitizer in combination with the photopolymerization initiator.
Examples of the photosensitizer include n-butylamine, n-dibutylamine, triethylamine, and triethylenetetramine.

In order to prevent gelation during storage, a polymerization inhibitor may be used in combination with the ultraviolet-curable resin composition used in the present invention. Examples of the polymerization inhibitor that can be used in combination include, for example, p-benzoquinone, hydroquinone, hydroquinone monomethyl ether, p-tert-butylcatechol,
Mono-tert-butylhydroquinone, α-naphthool, pyrogallol and the like can be mentioned.

The ultraviolet-curable resin composition used in the present invention, further,
Additives that are added to printing inks or paints can also be used. Additives that can be used in combination include, for example, antifoaming agents such as silicones; leveling improvers; surfactants such as polyoxyethylene glycol alkyl ethers and alkylbenzylammonium chlorides; anti-skinning agents such as eugenol and methyl ethyl ketoxime; Drying regulators such as cobalt acid, cobalt octylate, manganese nafleate, ascorbic acid, sodium p-toluenesulfonate, tertiary amine compound, triphenylphosphine; ultraviolet rays such as 2,2-dihydroxy-4-methoxybenzophenone Absorbent; white petrolatum,
Examples include film-strengthening agents such as paraffin wax, microcrystalline wax, polyethylene wax, and fluorine compounds.

The method of applying the ultraviolet-curable resin composition used in the present invention may be any of a roll coater method, a gravure coater method, and a blanket coater method. In addition, a solvent can be used, if necessary, to facilitate coating. As the solvent, a well-known solvent used for inks and paints can be used without any particular limitation. For example, n-hexane, n-heptane, ethyl acetate, butyl acetate, toluene, xylene and the like can be mentioned.

The inks used for lithographic printing are ultraviolet curable inks,
Oil-based inks may be used, and any of these may be used in combination.

Further, the application time of the ultraviolet-curable resin composition used in the present invention to the lithographic printing material can be applied regardless of the state of the ink. That is, a method of applying the ultraviolet-curable resin composition of the present invention before the ultraviolet-curable ink is irradiated with ultraviolet rays or before the oxidation-polymerization type oil-based ink leaves the printing machine and the ink is not cured. Less than,
A method. Any method (hereinafter, referred to as a B method) in which the ultraviolet-curable resin composition of the present invention is applied to the ink that has been cured for a long time.

The coating amount of the ultraviolet-curable resin composition used in the present invention on a lithographic printing material is 2 to 2 solids per square meter.
It is in the range of 10 g, preferably 3 to 8 g. If the coating amount is less than 2 g, it is liable to be affected by oxygen in the air and ultraviolet curing is insufficient, which tends to cause backing, which is not preferable. If the coating amount exceeds 10 g, the leveling of the cured surface is poor, and the function as a surface finishing agent tends not to be exerted.

[Examples] Hereinafter, the present invention will be described with reference to Examples. In the examples, “parts” indicates “parts by weight”.

Production Example 1 In a 2 liter four-necked flask equipped with a thermometer, a stirrer, a water separator and a gas inlet tube, 904 parts of linseed oil, 332 parts of isophthalic acid and 127 parts of glycerin were charged, and the system was blown with nitrogen gas. The temperature inside was raised to 250 ° C. over 2 hours, and the esterification reaction was carried out at 250 ° C. for 8 hours.
An alkyd resin (1) having an acid value of 7 and a molecular weight of 11,000 was obtained.

Using this alkyd resin (1), an ultraviolet curable resin composition (A) having the following composition was obtained.

(1) Phenyl carbitol acrylate 19 parts (2) Urethane acrylate 5 parts (3) Neopentyl glycol diacrylate 41 parts (4) Trimethylolpropane triacrylate 12 parts (5) Benzophenone 4 parts (6) Hydroxycyclohexyl phenyl ketone 4 Part (7) Alkyd resin (1) 15 parts Production Example 2 In a 2 liter four-necked flask equipped with a thermometer, a stirrer, a water separator and a gas inlet tube, 843 parts of linseed oil 240 parts of phthalic anhydride and 102 parts of glycerin The temperature of the system was raised to 250 ° C. over 2 hours while blowing nitrogen gas, and the esterification reaction was carried out at 250 ° C. for 8 hours.
An alkyd resin (2) having an acid value of 7 and a molecular weight of 13,000 was obtained.

Using this alkyd resin (2), an ultraviolet curable resin composition (B) having the following composition was obtained.

(1) Phenylcarbitol acrylate 19 parts (2) Urethane acrylate 5 parts (3) Stearic acid-modified pentaerythritol diacrylate 12 parts (4) Trimethylolpropane triacrylate 12 parts (5) Benzophenone 4 parts (6) Hydroxycyclohexylphenyl Ketone 4 parts (7) Alkyd resin (2) 15 parts Production Example 3 In a 2-liter four-necked flask equipped with a thermometer, a stirrer, a water separator, and a gas inlet tube, 819 parts of soybean oil, 272 parts of isophthalic acid, Charge 142.7 parts of trimethylolpropane, and blow the nitrogen gas through the system for 2 hours.
The temperature was raised to 0 ° C and the esterification reaction was carried out at 250 ° C for 8 hours. An alkyd resin having an oil length of 70%, an acid value of 4, and a molecular weight of 12,000 (3)
I got

Using this alkyd resin (3), an ultraviolet curable resin composition (C) having the following composition was obtained.

(1) Phenyl carbitol acrylate 19 parts (2) Urethane acrylate 5 parts (3) Polyethylene glycol diacrylate 41 parts (4) Trimethylolpropane triacrylate 12 parts (5) Benzophenone 4 parts (6) Hydroxycyclohexyl phenyl ketone 4 parts (7) Alkyd Resin (3) 15 parts Production Example 4 Using the alkyd resin (1) obtained in Production Example 1, an ultraviolet curable resin composition (D) having the following composition was obtained.

(1) 2-ethylhexyl polyethylene glycol acrylate 25 parts (2) urethane acrylate 7 parts (3) neopentyl glycol diacrylate 40 parts (4) trimethylolpropane triacrylate 10 parts (5) benzophenone 4 parts (6) hydroxycyclohexyl phenyl Ketone 4 parts (7) Alkyd resin (1) 10 parts Production Example 5 Using the alkyd resin (1) obtained in Production Example 1, an ultraviolet-curable resin composition (E) having the following composition was obtained.

(1) 30 parts of phenyl carbitol acrylate (2) 5 parts of urethane acrylate (3) 37 parts of neopentyl glycol diacrylate (4) 12 parts of trimethylolpropane triacrylate (5) 4 parts of benzophenone (6) hydroxycyclohexyl phenyl ketone 4 Part (7) Alkyd resin (1) 8 parts Comparative production example 1 The composition obtained by removing the alkyd resin (1) from the ultraviolet-curable resin composition (A) obtained in Production example 1 was used as the ultraviolet-curable resin composition (F). ).

Comparative Production Example 2 A composition obtained by removing the alkyd resin (1) from the ultraviolet-curable resin composition (D) obtained in Production Example 4 was designated as an ultraviolet-curable resin composition (G).

Examples and Comparative Examples Using "RI Tester" manufactured by Akira Seisakusho Co., Ltd., "Calton Caps Process Red" (oil-based ink manufactured by Dainippon Ink and Chemicals, Inc.) or "Dicure New" was applied to CRC paper.
"OL Process Beni" (ultraviolet curable ink manufactured by Dainippon Ink and Chemicals, Inc.). In the A method, immediately after the exhibition,
In the B method, after color development, after 24 hours at 20 ° C and 65% RH,
Using each "hand proofer" (150 mesh mesh anilox lattice type manufactured by PAMARCO), apply the ultraviolet-curable resin composition obtained in each of the production examples or each of the comparative production examples, and irradiate with ultraviolet rays (ultraviolet irradiation conditions: air cooling). Formula 120W / cm mercury lamp 1
By turning on a light and a conveyor speed of 20 m / min), each coated product of Examples and Comparative Examples was obtained.

(Evaluation Method and Evaluation Criteria of Coated Product) The gloss, the cellophane pressure-sensitive adhesive tape adhesiveness, and the secondary workability of each coated product were evaluated, and the results are shown in Table 1.

(Glossy) Gloss is 20 ° C after coating and curing the UV curable resin composition.
・ Measured for 60 ° / 60 ° reflective mirror gloss after standing at 65% RH for 24 hours.

(Adhesive property of cellophane adhesive tape) Adhesive property of cellophane adhesive tape was measured by applying Nichiban Co., Ltd. "Cellophane Tape No.405" to the test surface and reciprocating 10 times while pressing the fingernail.
The adhesiveness to the ink was evaluated according to the following three grades depending on the degree to which the ink adhered to the "cellotape".

 Excellent: The base paper adheres to the entire surface.

 Good: Part of paper, ink and gloss varnish adhered.

Poor: no ink adhered, only gloss varnish adhered to "Cellotape".

(Bendability) The bendability of the secondary workability was evaluated in the following three stages according to the state of the glossy varnish crack at the bent portion of the coated product by bending it 180 degrees.

 Excellent: no cracks.

 Good: Partially cracked.

 Bad: cracks all over.

(Gluing aptitude) Gluing aptitude is "Life Bond AV650" (glue manufactured by Niei Chemical Co., Ltd.) on one coated surface (glossy varnish surface) of two coated products.
Was applied to a width of 5 mm, a length of 50 mm, and a thickness of 1 mm, and quickly, five sheets were prepared by laminating the adhesive surface and the back surface of another coated material. This was left for 24 hours under the condition of 20 ° C. and 65% RH, and the following 3 was determined according to the number of adhered five test specimens.
It was rated on a scale.

 Excellent: 5 sheets.

 Good: 3-4 sheets.

 Bad: 0 to 2 sheets.

(Friction resistance) The friction resistance was evaluated under the load of 500 g of "Gakushin type friction fastness tester" manufactured by Daiei Kagaku Seisakusho, and evaluated in the following three stages according to the number of times of occurrence of scratches.

 Excellent: More than 800 times.

 Good: 300 to 800 times.

 Bad: 300 times or less.

[Effects of the Invention] According to the gloss processing method of the present invention, a gloss, a cellophane adhesive tape adhesiveness, a bending property, a gluing suitability and a friction resistance can be obtained on a lithographic printing material by using an ultraviolet curable resin composition. It is possible to form a coating film having excellent performance in secondary workability.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-53-115311 (JP, A) JP-A-56-142090 (JP, A) JP-A-62-121094 (JP, A) JP-A-1- 123875 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) B41M ^7/ 00-7/02

Claims (3)

(57) [Claims] A gloss processing method for a lithographic printed matter, comprising coating and curing an ultraviolet curable resin composition containing an alkyd resin on the lithographic printed matter. 2. The method according to claim 1, wherein the ultraviolet-curable resin composition contains a radically polymerizable monomer, a photopolymerization initiator and an alkyd resin. 3. The method according to claim 1, wherein the ultraviolet-curable resin composition contains a radically polymerizable monomer, an oligomer, a photopolymerization initiator, and an alkyd resin.