JP3085994B2 - Coated resin film with excellent offset printability - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated resin film excellent in offset printability which prevents the film from becoming uneven or curled due to the solvent in the offset ink even when offset printing is performed. About.

[0002]

2. Description of the Related Art Offset printing is used for printing on paper such as art paper, high-quality paper, coated paper, polyethylene terephthalate film, and polypropylene-based synthetic paper because multicolor printing can be easily performed. The dry offset ink has the composition shown in Table 1 shown below.

[0003]

[Table 1]

As the offset ink, general-purpose offset inks such as pulp paper and pulp coated paper are generally used (Table 2).

[0005]

[Table 2]

In order to speed up the drying time of this general-purpose offset ink, a quick-drying ink in which a resin and a mineral oil (a high-boiling petroleum solvent) are mixed with a drying oil is used as a vehicle of the ink. However, in order to improve the drying property of the polyvinyl chloride resin film or the polyvinyl chloride resin containing inorganic fine powder (salt white) using these general-purpose offset inks, or the stretched product and the ink, When printing is performed on coated paper having a pigment coat layer applied to these films, the polyvinyl chloride film swells due to the solvent of the offset ink used in the general-purpose offset printing (particularly, a high boiling petroleum solvent such as mineral oil). As a result, a so-called solvent attack occurs, such as partial unevenness of the printed film or curling of the entire film. Therefore, as an offset printing ink for a polyvinyl chloride resin film, an offset printing ink for a special non-absorbing material having a low high boiling point petroleum solvent is used (see Table 2) or a solvent-free UV is used. Irradiation-curable UV offset inks are used. One method of preventing swelling of a polyvinyl chloride resin film by a solvent (especially a high boiling point solvent) of a general-purpose offset printing ink is to provide a coating (pigment coat) layer on the front and back surfaces of the polyvinyl chloride resin film. Conceivable. However, in this method, since the amount of the solvent in the general-purpose offset printing ink accounts for 45 to 70% by weight, these solvents are liable to cause a solvent attack. Therefore, in order to absorb the solvent sufficiently in the coating agent layer and to prevent the polyvinyl chloride resin layer from being attacked by the solvent, the thickness of the coating agent layer applied to the front and back surfaces of the layer should be adjusted to each thickness. 35 microns (μm)
It is necessary to do the above. However, setting the thickness of the coating agent layer to 70 μm or more on both the front and back surfaces is not an advantageous method because it requires a long time for drying after coating and leads to an increase in the cost of the coated resin film.

[0007]

With such a special offset ink for polyvinyl chloride resin, when performing offset printing, it is difficult to adjust the balance between the amount of water and the ink as compared with the case where a general-purpose ink is used. Since the viscosity of the ink changes on the printing press and the workability deteriorates, printing shops are refrained from using this printing ink. Therefore, printing shops and ink manufacturers are limited,
The appearance of a polyvinyl chloride resin film that can use a general-purpose offset ink is desired. In other words, general printing companies usually perform offset printing on pulp-based paper such as high-quality paper and coated paper using general-purpose offset inks. Only then did the printing have to switch to a special non-absorbable offset ink for the material. Therefore, it takes a lot of time and labor to switch the ink, and general printing companies do not actively print polyvinyl chloride resin films such as synthetic paper. This has been one of the factors that hinder the spread of vinyl resin films or salt white for offset printing. An object of the present invention is to provide a coated polyvinyl chloride resin film which is not deformed by solvent attack of a general-purpose offset ink even when the thickness of a coating agent layer is reduced.

[0008]

[Means for Solving the Problems]

[Summary of the Invention] The present inventors have conducted intensive studies in view of the above problems, and as a result, have found that a solvent for preventing the penetration of a solvent of a general-purpose offset printing ink into both surfaces of a polyvinyl chloride resin film or salt white. A pigment coating layer (coating agent layer) is provided on both sides or on the surface where offset printing is to be performed, and a multi-color offset printing is performed using a general-purpose offset printing ink. However, the present invention is based on the finding that the printed polyvinyl chloride resin film or salt white can be made less likely to have irregularities or curl over the entire film (solvent attack). Is completed. That is, the present invention, on both sides of the polyvinyl chloride resin film substrate layer, provided with a solvent permeation prevention layer for preventing the penetration of the solvent in the offset printing ink component,
An object of the present invention is to provide a coated resin film having excellent offset printability, wherein a coating agent layer is provided on one or both sides of the solvent permeation preventing layer.

[Specific description of the invention] [I] Layer structure (1) Polyvinyl chloride resin film base layer Polyvinyl chloride resin film base layer constituting the coated resin film of the present invention having excellent offset printability As the polyvinyl chloride resin film used in the above, a polyvinyl chloride resin or a polyvinyl chloride resin mixed with an inorganic filler in an amount of 8 to 60% by weight is used for various film forming methods such as an inflation method, a T-die method, and a calendar method. It is obtained by molding. If necessary, those obtained by stretching these films may be used. The thickness of the polyvinyl chloride resin film is usually from 40 to 500 μm, preferably from 60 to 160 μm, depending on the use.

(2) Solvent Permeation Prevention Layer The solvent permeation prevention layer constituting the coated resin film having excellent offset printability of the present invention is a solvent attack (a solvent attack on a polyvinyl chloride resin film by a solvent in offset printing ink). It is provided on the front and back surfaces of the polyvinyl chloride resin film in order to prevent uneven dots and curls. This forms a film made of cross-linked polyvinyl alcohol, cross-linked casein, polyvinylidene chloride, polyacrylonitrile, polyacrylamide, polyvinyl fluoride, etc., and has excellent solvent resistance to mineral oil and high boiling petroleum solvent components. Is formed.
This solvent permeation prevention layer is formed not only on the surface on which offset printing is performed but also on the back surface side. In other words, printing paper that has been offset printed is stored while being stacked,
This is because the solvent during printing is prevented from penetrating from the surface of the printed matter one sheet below during storage and the occurrence of unevenness and curl is prevented.

As a primer for forming such a solvent permeation preventing layer, a vinylidene chloride content of 82 to 94% by weight and 18 to 6% by weight of another vinyl monomer such as alkyl acrylate, acrylonitrile and acrylic acid are used. A vinylidene chloride copolymer which is a polymer; a crosslinked polyvinyl alcohol obtained by mixing a crosslinking agent with polyvinyl alcohol having a saponification degree of 65 to 100%; acrylamide and / or methacrylamide 35 to 9
A copolymer of 8% by weight with 65 to 2% by weight of another vinyl monomer such as alkyl acrylate, alkyl methacrylate, styrene, acrolein, acrylic acid, 20 to 55% by weight of acrylonitrile and alkyl acrylate Ester, alkyl methacrylate, styrene, α-methylstyrene, acrylic acid, itaconic acid, copolymer with 80 to 45% by weight of other vinyl monomers such as vinyl acetate, polydifluoroethylene, difluoride Polyfluorinated resin such as ethylene / tetrafluoroethylene copolymer, N-methylolacrylamide, acrylamide, methacrylamide, etc. 1-10% by weight, acrylonitrile 5-30% by weight, alkyl acrylate, alkyl methacrylate , Acrylic acid, methacrylic acid and other vinyl monomers 85 to 60 %, A copolymer, such as cross-linked casein solution, aqueous solutions of these resins, emulsions or it toluene, mineral spirits, those dissolved in a solvent such as petroleum can be used. The thickness of the solvent permeation prevention layer varies depending on the resin used, but is generally 0.5 to 15 μm, preferably 3 to 10 μm.

[0012] (3) As the coating agent layer for improving the drying of the coating material layer offset printing ink, usually, pigment coating agents used as a coating agent for coated papers can be used. Such a coating composition is generally composed mainly of a component consisting of 50 to 90% by weight of an inorganic fine powder and 50 to 10% by weight (solid content) of an emulsion-type or water-soluble resin binder. If necessary, an antistatic agent may be added in an amount of 0.05 to 5% by weight. Examples of such inorganic fine powders include calcium carbonate, satin white, silica, titanium oxide, alumina, clay, talc, aluminum hydroxide and the like, zinc white, iron oxide and the like, and pigments. The particle size of this inorganic fine powder is 15 μm
Hereinafter, particularly, 0.1 to 10 μm is preferable. In addition, fine particles such as an organic colorant and polystyrene called plastic pigment may be added. As the resin binder, an ethylene / vinyl acetate copolymer emulsion, an ethylene / vinyl acetate / vinyl chloride copolymer emulsion,
Resin emulsions such as vinyl acetate / acrylic ester copolymer emulsions, styrene / butadiene rubber emulsions, cold-crosslinkable acrylic resin aqueous emulsions, urethane resin aqueous emulsions; water-soluble polymers such as starch, carboxymethyl cellulose, and polyvinylpyrrolidone A single product or a mixture of two or more products is used. In addition to the inorganic fine powder and the resin binder, a slight solvent or the like can be used for the purpose of facilitating coating. In addition, colorants, preservatives, flow improvers,
A wetting agent, a film-forming aid, an antifoaming agent, a plasticizer and the like may be blended. The coating method of the coating agent may be a normal coating method. The coated polyvinyl chloride resin film is dried, and a coating layer is formed on the front surface or the front and back surfaces of the film substrate. The thickness of the coating agent layer is generally 3 to 30 μm.

[II] Offset printing The thus obtained coating type polyvinyl chloride resin film of the present invention having excellent offset printability is subjected to offset printing by attaching an offset ink to the surface thereof. . (1) Offset ink As such an offset ink, generally, as shown in Tables 1 and 2, a base material composed of a pigment and a vehicle, and an auxiliary agent composed of a viscosity modifier, a drying regulator, and others are used. Basically, this coating resin film can use not only a general-purpose offset ink but also an offset ink for a non-absorbable material. Examples of the pigments include azo pigments such as risol red and benzidine yellow, permanent pigments such as permanent grin, permanent rhodamine, permanent blue and lake red C, organic pigments such as brilliant carmine 6B and phthalocyanine blue, alumina, and barium sulfate. , Bengala, graphite,
Inorganic pigments such as navy blue, titanium white, carbon black and the like can be mentioned. Examples of the vehicle include a synthetic resin, a vegetable oil (dry oil), and a solvent. Specific examples of these vehicles include a flaxseed oil type such as linseed oil and stand oil, an alkyd type such as a dry oil-modified alkyd resin, a rosin-modified phenolic resin, a mixed liquid of flaxseed oil and drill oil, or a low-viscosity flaxseed oil. A quick-drying resin type mainly composed of a resin varnish in which the viscosity is adjusted by dissolving in an oil varnish or the like and adding a petroleum fraction having a narrow boiling point range can be exemplified. Examples of the viscosity modifier include a solvent, a dilution varnish, and a compound. Examples of the drying regulator include a desiccant (dryer) drying inhibitor. Other components include a wax, a film enhancer, a backing inhibitor and the like.

(2) Offset printing method In order to perform offset printing of the offset ink on the polyvinyl chloride resin film of the present invention having excellent offset printability, a commercially available offset printing machine is used in the same manner as in normal offset printing. Can be done.

[0015]

The present invention will be described in more detail with reference to the following Examples and Comparative Examples. The parts and percentages in the examples are on a weight basis unless otherwise specified. (A) 55 parts by weight Preparation Example 1 Polyvinyl chloride resin polyvinyl chloride resin film substrate layer, 5 parts of titanium oxide, with a heavy 35 parts of calcium carbonate powder, and a mixture consisting of a plasticizer 5 parts extruder It is melt-kneaded, extruded into a sheet at a temperature of 200 ° C. from a die, and then cooled to a thickness of 100
A μm salt white film was obtained.

(B) Primer (solvent penetration preventing layer forming agent)
Preparation Example 1 Aqueous acrylamide copolymer solution 100 parts of a vinyl monomer mixture consisting of 22 parts of acrylamide, 35 parts of acrylonitrile, 35 parts of methyl methacrylate and 8 parts of N-methylolacrylamide were added to water 1
20 parts, isopropanol 5 parts, sulfuric acid half ester of p-nonylphenol 0.5 part, p-nonylphenol 2
0.4 part of 5 mol ethylene oxide adduct and 0.7 part of potassium persulfate were blended and added dropwise to the flask.
Emulsion polymerization was performed at 4 ° C. for 4 hours. Then, after cooling to room temperature, the mixture was neutralized with aqueous ammonia to prepare an aqueous acrylamide copolymer solution having a pH of 7 to 8.

Example 2 Acrylonitrile resin aqueous emulsion Temperature controller, squirrel type stirrer, reflux condenser, supply vessel,
The following raw materials were charged into a reaction vessel equipped with a thermometer and a nitrogen inlet tube. The following mixture was used as feed I: Water 200 parts 35% solution of the anionic emulsifier ^{25 parts} acrylonitrile 175 parts n-butyl acrylate 310 parts acrylic acid 15 parts As feed II, a solution of 2.5 parts potassium persulfate in 85 parts water was prepared. After replacing the inside of the reactor with nitrogen gas,
To the charge is added 10% of said feed I and the mixture is added to 9
Heated to 0 ° C. Then, 10% of said feed II was injected into the reactor, and the remaining feeds I and II were fed into the reactor evenly in parallel over 3 to 3.5 hours. After maintaining the temperature at 90 ° C. for 1.5 hours after the completion of the supply, the reactor was cooled to room temperature. The pH of the dispersion was adjusted to 7 to 8 with aqueous ammonia to obtain an aqueous dispersion having a solid content of 50%.

Example 3 Cross-linked polyvinyl alcohol aqueous solution A mixture of a 20% aqueous solution of polyvinyl alcohol having a saponification degree of 96% and a methylolated melamine resin was used. Example 4 Vinylidene chloride copolymer emulsion Vinylidene chloride (92%) / methyl acrylate (4%)
An aqueous emulsion of acrylonitrile (3%) / acrylic acid (1%) copolymer was used. Example 5 Polyvinylidene Fluoride Solution A dimethylformamide solution of vinylidene difluoride resin was used. Example 6 Acrylamide Copolymer Acrylamide 8 parts, diacetone acrylamide 1.5
Parts, 0.5 parts of lauryl methacrylate, 1.5 parts of isopropyl alcohol, 80 parts of water, and 0.05 part of potassium persulfate were reacted at 55 ° C. for 3 hours to obtain an aqueous solution of an acrylamide copolymer. Example 7 Crosslinked Casein 10 parts by weight of casein was dissolved in 85 parts by weight of aqueous ammonia having a concentration of 1.2% by weight, and 0.5 part by weight of ammonium chloride was added thereto. Then, 5 parts by weight of a melamine-formaldehyde precondensate was added with stirring to obtain an aqueous solution of crosslinkable casein. Example 8 Crosslinked Casein 10 parts by weight of casein, 2 parts by weight of urea, 83 parts by weight of water, and 1 part by weight of trimethylenetetramine were mixed to prepare an aqueous casein solution. Glycidyl ether of bisphenol A “Epicoat 828 (trade name) J10 parts by weight 2” manufactured by Yuka Shell Epoxy Co., Ltd. was added thereto to obtain an aqueous solution of crosslinkable casein.

Example 1 On both sides of the salt white film obtained in Example 1 of (A), the aqueous solution of the acrylamide copolymer of Example 1 of (B) was applied so that the thickness of each film became 3 μm. After drying at room temperature, the following coating agents were applied on both sides of this anchor coat layer so that a film of 8 μm each was obtained.
For 1 minute to obtain a coated paper. (C) Coating agent Styrene / butadiene rubber latex 35 parts Starch 10 parts Antistatic agent (10% aqueous solution) 10 parts Calcium carbonate 30 parts Titanium white (titanium oxide) 10 parts Clay 60 parts Dispersant (Na tripolyphosphate) 0 .5 parts Antifoaming agent (San Nopco SN-DF-113) 0.1 part

(D) Evaluation A general-purpose offset ink for pulp paper (linseed oil, mineral oil,
Multi-color printing offset printing was performed using four colors of red, indigo, indigo, black and yellow inks of Graph G of Dainippon Ink Industries, Ltd. (based on pigments and resins). After leaving this printed part for 60 minutes with 1,000 sheets stacked, the printed matter (A2 size) was examined for the occurrence of unevenness. Solid printing was performed on the entire surface of the coated synthetic paper using a quick-drying offset ink “New Best One Process Ink M” manufactured by Toka Pigment Co., Ltd. so that the transfer amount was 1 g / m ² . . After standing for 60 minutes with 1000 sheets of the printed matter stacked, three of them were taken out, and the printed matter was cut into a size of 12 × 5 cm and left on a desk for one day. The measurement was performed as shown in FIG. Table 3 shows the results of the presence or absence of curling.

[0021] directly Shioshiro film of Example 1 of Comparative Example 1 above (A), performs a similar multicolor offset printing as in Example 1, and the presence or absence of curling,
The presence or absence of the irregularities shown in FIG. 2 was examined. Table 3 shows the results.

Comparative Example 2 A coated paper was obtained in the same manner as in Example 1 except that the acrylamide resin primer layer was not provided. This was similarly evaluated for printability with a general-purpose offset printing ink. Table 3 shows the results.

Example 2 The crosslinked polyvinyl alcohol aqueous solution of Example 3 of (B) was applied to the front and back surfaces of the salt white film obtained in Example 1 of (A) such that a 5 μm film was obtained. After drying, the coating agents shown below were applied to both sides of the crosslinked polyvinyl alcohol film, and dried to obtain coated paper having a coating agent layer having a thickness of 8 microns. Coating composition SBR latex (solid content 50%) 32 parts Acrylic ester resin latex (solid content 50%) 11 parts Clay 70 parts Calcium carbonate with 1.5 μm particle size 25 parts Titanium oxide 5 parts ST -1100 aqueous solution ^* (solid content 4%) 12 parts Dispersant 1 part ^* Mitsubishi Yuka Corporation water-soluble acrylic resin antistatic agent

Example 3 The aqueous acrylonitrile resin emulsion obtained in Example 2 of (B) was applied to the front and back surfaces of the salt white film obtained in Example 1 of (A) so that a 4 μm film was obtained. And dried. Then, the coating agent used in Example 1 was applied on the front and back surfaces so that a coating film having a thickness of 8 μm was obtained, and dried to obtain a coated paper.

Examples 4 to 9 and Comparative Examples 3 to 5 Coated papers were obtained by changing the types and thicknesses of primers and coating agents as shown in Table 3, and the coated papers were obtained in the same manner as in Example 1 The multicolor printability with the printing ink was evaluated. Table 3 shows the results. In addition, the drying property of the offset printing ink in Table 3 indicates the drying time of the ink that can be transferred to the next step (for example, bookbinding or folding) after offset printing.

[0026]

[Table 3]

[0027]

As described above, the coated resin film of the present invention having excellent offset printability is provided with a solvent permeation preventing layer for preventing the penetration of the solvent in the offset ink. Layer with solvent (high boiling petroleum solvent)
The thickness of the coating agent layer can be reduced because it is prevented from penetrating, and even if a general-purpose offset printing ink is printed on the surface of the coating agent layer, the printed coating layer can be printed. Irregularities are generated in the type of polyvinyl chloride resin film or salt white, and curl is hardly generated in the entire film.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a method for measuring the curl height of a printed material according to an embodiment of the present invention.

FIG. 2 shows a perspective view of an offset multicolor print having irregularities caused by a vehicle in the offset printing ink.

[Description of Signs] 1 Printed matter 2 Flat plate 3 Concave or convex h Curl height

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41M 1/06 B41M 1/30 C08J 7/04 CEV B32B 7/00-7/02

Claims (2)

(57) [Claims] 1. A solvent permeation preventing layer for preventing permeation of a solvent in an offset printing ink component is provided on both surfaces of a polyvinyl chloride resin film base material layer, and a coating is applied to one or both sides of the solvent permeation preventing layer. A coated resin film having excellent offset printability, characterized by having a coating layer. 2. A solvent permeation preventing layer for preventing permeation of a solvent of an offset printing ink is formed of a cross-linked polyvinyl alcohol, a cross-linked casein, or acrylonitrile in an amount of 20 to 55.
Acrylonitrile copolymer containing 35% to 98% by weight of acrylonitrile copolymer, acrylamide copolymer containing 35 to 98% by weight of acrylamide, and at least one resin selected from polyvinylidene chloride and polyvinylidene fluoride. The coated resin film having excellent offset printability according to claim 1.