JP2006291393A - Coated paper for web offset printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a coated paper for web offset printing in which offset wrinkle (wavy wrinkle of paper) generated in a drying step of web offset printing is remarkably improved and generation temperature of blister is kept in a practically sufficient level. <P>SOLUTION: In the coated paper for web offset printing in which one or more pigment coated layers containing a pigment and an adhesive as a main component are provided on at least one surface of a raw paper, the raw paper contains a mixture of a cationic fatty acid amide with a nonionic wetting agent in an amount of 0.1-10 mass% based on raw paper mass. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a coated paper for rotary offset printing, and more particularly, to a coated paper that can prevent the occurrence of off-roll wrinkles that tend to occur in a drying process after printing during offset rotary printing.

In recent years, the printing industry has shifted from an offset sheet-fed printing method (hereinafter referred to as sheet-fed printing) to an offset rotary printing method (hereinafter referred to as off-wheel printing) with labor saving and speeding up. . The off-ring printing has a higher printing speed and can save labor in the post-process, so that the productivity is much higher than the sheet-fed printing.
However, off-wheel printing has several quality problems that are not seen in sheet-fed printing because hot air drying is performed immediately after printing. Among them, the most important and difficult problem to solve is off-wheel wrinkles (sometimes referred to as “folds” in the printing industry). A mechanism for generating wrinkles due to the difference in drying shrinkage rate has been proposed.

  In the past, attempts have been made to reduce off-wrinkles. For example, while maintaining the freeness of the pulp of the base paper within a specific range, the air permeability of the base paper is also regulated to a specific area with good air permeability. A method for suppressing the generation of ring wrinkles (see Patent Document 1) has been proposed. However, since coated paper for off-wheel printing is produced through a series of processes such as pulp preparation, papermaking, coating, and pressurizing finishing with a calendar, it simply involves the freeness of pulp and the air permeability of the base paper. Just adjusting the degree does not solve the off wrinkle sufficiently.

  Also, it is defined by the ratio of the maximum and minimum values of the microwave transmission intensity of the base paper measured by microwave measurement, the Fenchel water immersion elongation in the direction perpendicular to the paper making direction, and the value obtained by dividing the air permeability by the paper thickness. Means have also been proposed for eliminating off-wrinkles by using a stencil sheet (see Patent Document 2). However, since the cause of off-roll wrinkles is not only the fiber orientation of the base paper, a satisfactory effect cannot be obtained.

  In addition, a technique for eliminating or reducing off-wrinkles has been proposed by defining the take-up moisture and the internal interlayer strength of the base paper with a specific relational expression (see Patent Document 3). However, in order to satisfy this relational expression, it is necessary to keep the water content of the coated paper low. However, a decrease in water content causes a phenomenon that the coating layer breaks in the subsequent folding process, so-called “folding”. There is a risk of causing.

  Moreover, the freeness of hardwood pulp having a lumen width (L) to fiber width (D) ratio L / D of 0.15 to 0.35 is set to 200 to 350 ml, and this is blended in an amount of 10 to 35 mass% of the total pulp. Although a method of suppressing off-wrinkle has been proposed (see Patent Document 4), such a pulp has a rigid fiber and a square shape and is large enough to be smoothened by a calendar process. There is a difficulty that it is difficult to obtain.

  Further, by providing a polyvinyl alcohol-containing coating layer containing polyvinyl alcohol or polyvinyl alcohol and a pigment as components on a base paper, and providing a pigment coating layer thereon, the drying shrinkage force and air permeability of the resulting coated paper Etc. are adjusted within a specific range, so that there is almost no off-wrinkle generation, and a coated paper for printing that causes little misregistration in gravure printing and flexographic printing has been proposed (see Patent Document 5). . However, although this proposal can significantly reduce or eliminate the occurrence of off-roll wrinkles, it is necessary to thicken the polyvinyl alcohol-containing coating layer to some extent, and there is a problem that production facilities are restricted.

  Furthermore, between the web path behind the dryer exit of the web offset press and passing between the heating roll and the pressure roll whose surface free energy is 30 mN / m or less, and by humidifying the paper, it is reduced by the dryer. There has also been proposed a method of mechanically eliminating wrinkles on the same principle as a steam iron by replenishing the generated moisture and simultaneously passing between a heating roll and a pressure roll (see Patent Document 6). However, in this method, depending on the depth and number of the generated wrinkles, several wrinkles may be combined and pressed between the rolls, resulting in a defect that greatly impairs the product value.

  In addition to this, a method for reducing off-wrinkles by applying a surface sizing agent or a surface sizing agent and a plastic pigment to the surface of the coating layer of the coated paper (see Patent Documents 7 and 8) has also been proposed. However, a sufficient effect cannot always be obtained.

JP 58-186700 A Japanese Patent Application Laid-Open No. 06-056786 JP 09-291696 A Japanese Patent Laid-Open No. 10-226979 JP 2000-45199 A JP 2002-347111 A JP 2002-263888 A JP 2004-091986 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide a coated paper for offset rotary printing that does not cause the above-described drawbacks and hardly generates off-roll wrinkles.

The present invention relates to a coated paper for offset rotary printing in which at least one surface of a base paper is provided with at least one pigment coating layer mainly composed of a pigment and an adhesive. As the base paper, a cationic fatty acid amide and a nonionic wetting are used. A base paper containing 0.1 to 10% by weight of a mixture with the agent is used.
The base paper may further contain polyacrylamide as a paper strength enhancer or may not contain it. However, when it is contained, it is preferable to keep it within a range of 1% by mass or less based on the mass of the base paper. The polyacrylamide used at that time is preferably branched polyacrylamide.
The base paper contains a filler having an apparent specific gravity (conforming to JIS K 6220-1-2001) of 0.5 g / ml or less and an average particle diameter of 1 μm or more so that the paper ash content is 2 to 20% by mass. This embodiment is also a preferred embodiment.

  The coated paper for rotary offset printing of the present invention has almost no off-wrinkle and excellent blister resistance, and therefore has the advantage that it can be used as a coated paper for high-grade printing that requires the quality of printed matter. is there.

The present invention is important when a mixture of a cationic fatty acid amide and a nonionic wetting agent is contained in the base paper of the offset rotary printing coated paper in a proportion of 0.1 to 10% by weight with respect to the base paper weight. There is a special feature.
The reason why the off-wrinkle is greatly improved by adding such a cationic fatty acid amide and a nonionic wetting agent to the base paper is estimated as follows.
The cationic fatty acid amide is easily adsorbed to the pulp fiber due to its ionicity, and forms a rod-like micelle centering on the pulp fiber. In addition, since a hydrophobic group is located outside in the micelle, a nonionic wetting agent coordinates with the alcoholic hydroxyl group facing outward. By taking this three-dimensional structure, the water dispersibility of the pulp fiber is not inhibited. On the other hand, in the papermaking dehydration step, the micelles inhibit the contact between the pulp fibers, so that a bulky paper with many voids and few bonds between the pulp fibers can be obtained. In such a paper, although the pulp fiber itself shrinks in the drying process of the printing press, the shrinkage force does not propagate to the entire paper surface because there are few bonds between the fibers. For this reason, it is thought that the base paper in which the cause of occurrence of off-roll wrinkles is reduced can be obtained.

As the cationic fatty acid amide in this mixture, various compounds can be used regardless of saturated, unsaturated, linear or branched. If the carbon chain of the fatty acid is too short, the effect of inhibiting the contact between the pulp fibers is small. On the other hand, if the carbon chain is too long, the hydrophobicity becomes too strong and the pulp fiber may be difficult to disperse in water. It is desirable to use an amide compound of a fatty acid having about 5 to 21 carbon atoms excluding the carbon of the carbonyl group. In the branched fatty acid amide, it is preferable to use an amide compound having about 5 to 21 carbon atoms that forms the longest straight chain. Further, the cationization method of the fatty acid amide is not particularly limited, but generally a method in which the amide moiety -CONH _{2 is changed} to -CONH ₃ ⁺ is used.

Nonionic wetting agents include polyoxyethylene-fatty acid monoethanolamide adduct, polyoxypropylene-fatty acid isopropanolamide adduct, nonylphenol-ethylene oxide adduct polyoxyethylene or polyoxypropylene adduct, polyethylene Examples include glycols, polyalkylene glycols such as poly-oxyethylene-oxypropylene glycol and polypropylene glycol, and glycerin. Of these, compounds having more alcoholic hydroxyl groups such as polyalkylene glycols and glycerin are preferred.

In the present invention, the mixing ratio of the cationic fatty acid amide and the nonionic wetting agent is preferably in the range of 100: 5 to 100: 30 in terms of solid content mass ratio, which is suitable for micelle formation.
As the mixture of the cationic fatty acid amide and the nonionic wetting agent, for example, those commercially available from Riken Green Co., Ltd. as Prosoft TQ216, Prosoft TQ218, Prosoft TQ230, and Prosoft TQ236 can be used. .

  In the present invention, as described above, the mixture of the cationic fatty acid amide and the nonionic wetting agent is contained at a ratio of 0.1 to 10% by mass with respect to the mass of the base paper. When the content of the mixture is less than 0.1% by mass, the effect of micelle formation is not exhibited, and as a result, the effect of improving off-roll wrinkles cannot be obtained. On the other hand, if it exceeds 10% by mass, hydrogen bonds between pulp fibers are excessively inhibited, and paper strength is greatly reduced. In order to compensate for this, it is necessary to use a paper strength enhancer, which is not realistic. .

The base paper used in the present invention can be produced by making paper according to a conventional method from a paper stock obtained by incorporating pulp as a main component and a mixture of a cationic fatty acid amide and a nonionic wetting agent.
As such pulp, hardwood bleached kraft pulp, softwood bleached kraft pulp, mechanical pulp, and deinked waste paper pulp can be appropriately blended and used.
Examples of mechanical pulp include unexposed and semi-exposed such as Stone Grand Pulp (GP), Pressurized Stone Grand Pulp (PGW), Refiner Grand Pulp (RGP), Chemi Grand Pulp (CGP), and Thermomechanical Pulp (TMP). Or bleached pulp can be used.

In addition, as deinked waste paper pulp, the following waste paper deinked can be used.
Used paper classified as “super white, card”: high quality paper generated in bookbinding / printing factories, unprinted cream and dragonflies, waste paper with blue / red ruled paper, used cards for computers, etc.
Used paper classified as “imitation and color”: High quality paper with black ink printing, quality with color printing, Kent, and art paper printing.
Waste paper classified as “special white, medium white, white Manila”: medium quality paper, modified paper, unprinted manila balls and dragonflies, damaged paper with blue and red rules.
Wastepaper classified as "newspaper": Wastepaper wastepaper generated from households, companies and government offices.
Waste paper classified as “magazine”: Waste paper generated from households, companies, and public offices.

In the stock, starch, oxidized starch, cationized starch, carboxymethylated starch, carboxymethylcellulose, polyvinyl alcohol, anionic, cationic or amphoteric polyacrylamide can be used as an internal paper strength enhancer. .
In recent years, there has been a growing demand for paper containing a large amount of deinked wastepaper pulp. In special cases, 100% of the pulp components may be deinked wastepaper pulp, and blistering occurs due to a decrease in paper strength. There is a fear.
However, excessive addition of a paper strength enhancer may promote the occurrence of off-ring wrinkles, so the use of a paper strength enhancer is the minimum amount necessary to suppress the occurrence of paper breaks and blisters during printing. Addition is preferred.

When the internal addition of the paper strength enhancer is required, among the above-described internal strength enhancers, polyacrylamide is used, so that the required paper strength can be obtained without aggravating off-wrinkles. It is preferable because it can be maintained.
Among the polyacrylamides, when branched polyacrylamide is used, the branched chains can effectively bind the cellulose fibers, and the effect of increasing the paper strength can be obtained with a small amount of addition, and it is effective regardless of the pH of the stock. Is preferable.

Examples of such branched polyacrylamide include “Polystron 1274C” commercially available from Arakawa Chemical Industries, Ltd.
In the present invention, even when polyacrylamide is used as the paper strength enhancer, if the base paper contains polyacrylamide exceeding 1% by weight based on the weight of the base paper, off-roll wrinkles may be deteriorated. It is preferable to add so as to be 1% by mass or less based on the mass of the base paper.

  In the present invention, a filler can also be blended in the paper stock when making the base paper, and such a filler is not particularly limited, for example, clay, calcined clay, diatomaceous earth, talc, kaolin, calcined Kaolin, deramikaolin, heavy calcium carbonate, light calcium carbonate, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide, silicon oxide, amorphous silica (white carbon, etc.), amorphous silica, aluminum hydroxide, calcium hydroxide Inorganic fillers such as magnesium hydroxide and zinc hydroxide, and organic fillers such as urea-formalin resin, polystyrene resin, phenol resin, and fine hollow particles can be used alone or in appropriate combination of two or more.

Among the above fillers, the apparent specific gravity measured by the method defined in JIS K 6220-1-2001 “Rubber Compounding Agent—Test Method—Part 1: General” is 0.5 g / ml or less, In addition, it is preferable to use a bulky filler having an average particle diameter of 1 μm or more measured by a laser diffraction type particle size distribution analyzer (SALD-2000, manufactured by Shimadzu Corporation). This is because by arranging a bulky filler between the pulp fibers, the binding between the pulp fibers can be physically inhibited, and off-ring wrinkles can be further reduced.
As such a bulky filler, for example, amorphous silica such as white carbon or amorphous silica is preferably used.

Incidentally, when the average particle size of the internal filler is less than 1 μm or the apparent specific gravity exceeds 0.5 g / ml, it is difficult to obtain the effect of further improving the off wrinkles.
Although it does not specifically limit about the content rate of a filler, when considering paper strength and raw paper smoothness, it is preferable to add so that it may become 2-20 mass% as paper ash content, and especially paper ash content is 5-15 mass. It is more preferable to add internally so that it becomes%. When the paper ash content is less than 2% by mass, the effect of inhibiting the binding between pulp fibers is small, and it is difficult to obtain the effect of further reducing off-wrinkles. Further, when the internal filler is blended so as to exceed 20% by mass as a paper ash content, the paper strength is significantly lowered, the smoothness of the base paper is deteriorated, and the value as a coated paper may be impaired.
In the present invention, a bulky filler and other fillers can be used in combination. In that case, the filler may be added so that the total paper ash content is 2 to 20% by mass.

In the paper material, a sizing agent, a fixing agent, a fluorescent brightening agent, a coloring dye, and the like can be appropriately added as necessary.
There is also no particular limitation on the paper making method of the base paper, and an acidic paper making method or a neutral or alkaline paper making method can be arbitrarily adopted, and various types of paper machines such as long net, on-top, twin wire, etc. can be used as paper making equipment. . As conditions for papermaking, when the draw is weakened and the orientation of the base paper is lowered, there is a tendency to improve the off-wrinkle.
The basis weight of the base paper is not particularly limited, but is generally about 25 to 100 g / m ² .

In the present invention, the base paper thus produced can be subjected to size press treatment, and as the chemical used for such size press treatment, various conventionally used starches, polyvinyl alcohol, acrylamide polymers and the like are used. it can. In the size press liquid, wax, styrene resin, olefin resin, styrene-acrylic resin, styrene-maleic acid resin, styrene-maleic acid-acrylic resin, higher fatty acid resin, amine-epichlorohydrin resin Etc. can also be added suitably. In addition, although there is no restriction | limiting in particular about the adhesion amount in the case of performing a size press process, Generally, about 0.1-10 g / m < ² > is preferable at the dry adhesion amount of both surfaces total.

In the present invention, the pigment coating layer formed on the base paper is an aqueous system comprising a pigment coating composition containing a pigment and an adhesive as main components, as in the case of producing a conventional coated paper for printing. Paint is used.
As such a pigment, one or more kinds such as clay, kaolin, aluminum hydroxide, calcium carbonate, titanium dioxide, barium sulfate, zinc oxide, satin white, calcium sulfate, talc, and plastic pigment can be selected and used.
Among these pigments, the average particle diameter measured with an X-ray transmission type particle size distribution analyzer (Cedigraph 5100, manufactured by Micrometrics) is 0.15 to 0.5 μm, more preferably 0.15 to 0.5. When 3 μm of kaolin is contained in the range of 50 to 100% by mass of the whole pigment, generation of off-ring wrinkles is further improved, which is desirable.

  Examples of the adhesive include conjugated diene copolymer latex such as styrene-butadiene copolymer latex, methyl methacrylate-butadiene copolymer latex, styrene-methyl methacrylate-butadiene copolymer latex, acrylic ester and / or methacrylate ester. Acrylic polymer latex such as polymer latex or copolymer latex, vinyl polymer latex such as ethylene-vinyl acetate polymer, or these various polymer latexes modified with functional group-containing monomers such as carboxyl groups Water-dispersible adhesive such as polymer or copolymer latex, synthetic resin adhesives such as polyvinyl alcohol and olefin-maleic anhydride resin, oxidized starch, positive starch, esterified starch, starch such as dextrin, carboxy Methyl cell Over scan, a water-soluble adhesive such as cellulose derivatives such as hydroxyethyl cellulose and the like. As the adhesive, one or more of these water-dispersible and / or water-soluble adhesives can be appropriately selected and used.

In addition, as for the mixture ratio of a pigment and an adhesive agent, 5-25 mass parts adhesive agent is generally used with respect to 100 mass parts of pigments.
In the present invention, the coating layer of the pigment coating composition may be a single layer or a multilayer. However, regardless of whether the coating layer is a single layer or multiple layers, when forming the coating layer, the adhesive is 5 to 25 parts by mass per 100 parts by mass of the pigment as the adhesive of the entire coating layer. Adjust it. When the amount of adhesive is less than 5 parts by mass, the pigment coating layer strength that can withstand offset printing cannot be obtained. On the other hand, when the amount of adhesive exceeds 25 parts by mass, the occurrence of blistering during the drying process of offset rotary printing or There is a risk of ink drying failure.
The pigment coating composition may further contain auxiliary agents such as water retention agents, thickeners and various dyes as necessary.

In applying the water-based paint of the pigment coating composition to the base paper, a coating apparatus generally used for the production of coated paper can be used, for example, a blade coater, an air knife coater, a roll coater, a reverse roll coater, a bar coater, On-machine method or off-machine method using coating equipment such as curtain coater, die slot coater, gravure coater, Champlex coater, 2-roll size press coater, gate roll size press coater, film metering size press coater In at least one side of the base paper, it is applied in a single layer or multiple layers.
The solid content concentration of the pigment coating composition at the time of coating can be generally selected in the range of 40 to 75% by mass, but is preferably in the range of 45 to 70% by mass in consideration of operability. The coating amount per coating layer is generally selected in the range of 3 to ²⁰ g / m ² per side in terms of dry weight.

  Also, as a method of drying the wet coating layer, for example, a steam heating cylinder, a heated hot air air dryer, a gas heater dryer, an electric heater dryer, an infrared heater dryer, a high frequency heater dryer, or the like, or laser heating, electron beam heating Various methods such as dielectric heating are used alone or in combination. As drying conditions at the time of drying, it is necessary that the temperature of the wet coating layer be equal to or higher than the glass transition temperature of the latex used as the adhesive. For example, in the case of a hot air heating dryer, the hot air temperature is 120 to 120 ° C. A range of 180 ° C. and a hot air flow rate of 20 to 60 m / sec is preferably used. If the temperature of the wet coating layer during drying is equal to or lower than the glass transition temperature of the latex used as an adhesive, the latex is dried without functioning as an adhesive. The layer may adhere to the roll and peel off.

  After the pigment coating layer is formed, it is usually passed through a calendar and finished as a product. As the calendar at that time, for example, various calenders composed of metal rolls or metal drums and elastic rolls such as super calenders, gloss calenders, and soft compact calenders are used as appropriate in on-machine or off-machine specifications. The

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples and comparative examples, “parts” and “%” represent “parts by mass” and “% by mass”, respectively, unless otherwise specified.
In addition, the coated paper for rotary offset printing prepared in Examples and Comparative Examples was evaluated by the following evaluation methods, and the results are shown in Table 1.

・ Evaluation method for off-roll wrinkles Using an offset rotary printing press (Mitsubishi Lithopia L-BT3-1100 / Mitsubishi Heavy Industries), both sides have a 4-color solid design, one side has a 4-color solid design, and the other side has It is a combined design with a light pink pattern. The printing speed is 330 m / min, the paper surface temperature at the outlet of the dryer is 120 ° C, and the cooling roll after passing through the dryer is printed with 10 ° C cooling water and folded continuously. Processed. After printing, the degree of off-ring wrinkles was visually evaluated according to the following criteria.
AA: Off-ring wrinkles do not occur.
A: A wide off-ring wrinkle partially occurs, but the wrinkle depth is relatively shallow, and there is no problem at all.
B: Wide off-ring wrinkles occur throughout, but the wrinkle depth is relatively shallow, and there is no problem.
C: A large number of wide off-wrinkles are generated on the whole, and the wrinkle depth is moderate, which is a problem level.
D: A level where a large number of narrow off-wrinkles are generated throughout the entire wrinkle and the wrinkle is deep.

-Blister generation temperature Under the printing conditions of the above-mentioned off-ring wrinkle evaluation, the drying temperature was increased without changing the printing speed, and the presence or absence of blistering was evaluated at the double-sided, four-color printing section of the print sample. The paper surface temperature at the outlet of the dryer when blistering was observed was taken as the blistering temperature.
When the blister generation temperature is 140 ° C. or higher, it is a level at which printing can be performed without any problem.

Example 1
(Manufacture of base paper)
Light pulp calcium carbonate as a filler is added to a pulp slurry composed of 50 parts LBKP (freeness 550 ml / csf) and NBKP 50 parts (freeness 580 ml / csf) so that the paper ash content becomes 6.5%, and further, AKD as an internal sizing agent. Sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical) 0.1% (vs. pulp, solid content conversion), pre-gelatinized cationic starch (trade name: Ace K, manufactured by Oji Corn Starch) 0.5% (To pulp, solid content conversion) is added, and then the content of the mixture of the cationic fatty acid amide and the nonionic wetting agent (trade name: Prosoft TQ-230, manufactured by Riken Green) is 1% with respect to the base paper mass. Thus, a paper stock obtained was added, and the paper stock was made to prepare a base paper having a basis weight of 40 g / m ² and a moisture content of 5.0%.

(Manufacture of coated paper for printing)
A pigment consisting of 50 parts of heavy calcium carbonate (trade name: FMT90, manufactured by Phimatech) and 50 parts of fine kaolin (trade name: Milagros OP, average particle size: 0.25 μm, manufactured by Engelhard) was put into water with a Coreless disperser. Dispersion gave a pigment slurry. Styrene-butadiene copolymer latex (trade name: PA-9000, manufactured by Nippon A & L Co., Ltd.) 10 parts (solid content), pregelatinized oxidized starch (trade name: Ace A, manufactured by Oji Corn Starch) 3.5 parts ( Solid content), an antifoaming agent, a fluorescent whitening dye, and a printability improver were added to finally prepare a coating solution for a pigment coating layer having a solid content concentration of 64%. This coating solution was coated on the base paper obtained above with a blade coater so that the dry coating amount per side was 8 g / m ² and dried to obtain a double-sided coated paper. Next, this double-sided coated paper was smoothed under a condition of a linear pressure of 100 kg / cm ^{2 with} a four-stage super calender consisting of a metal roll and a resin roll to obtain a coated paper for offset rotary printing.

Example 2
In the production of the base paper of Example 1, Example 1 was used except that 3% of branched polyacrylamide (trade name: Polystron 1274C, manufactured by Arakawa Chemical) was added to the stock (vs. pulp, solid content conversion). Similarly, a coated paper for rotary offset printing was obtained.

Example 3
In the production of the base paper of Example 2, instead of adding light calcium carbonate as a filler so that the paper ash content was 6.5%, an apparent specific gravity of 0.2 g / ml and a laser diffraction type particle size distribution meter Amorphous silica having an average particle size of 18.3 μm (trade name: Toxeal GU-N, manufactured by Tokuyama Soda) was added so that the paper ash content would be 3%, and light calcium carbonate containing 3. A coated paper for rotary offset printing was obtained in the same manner as in Example 2 except that it was added so as to be 5%.

Example 4
In the production of the base paper of Example 2, as a filler, instead of adding light calcium carbonate so that the paper ash content is 6.5%, amorphous silica (trade name: Toxeal GU-N, manufactured by Tokuyama Soda) is used. A coated paper for rotary offset printing was obtained in the same manner as in Example 2 except that the paper ash content was 6.5%.

Comparative Example 1
In the production of the base paper of Example 1, the same as Example 1 except that the paper was made without adding a mixture of a cationic fatty acid amide and a nonionic wetting agent (trade name: Prosoft TQ-230, manufactured by Riken Green). Thus, a coated paper for offset rotary printing was obtained.

Comparative Example 2
In the production of the base paper of Example 1, instead of a mixture of a cationic fatty acid amide and a nonionic wetting agent (trade name: Prosoft TQ-230, manufactured by Riken Green), a cationic fatty acid amide (trade name: Neutron, A coated paper for rotary offset printing was obtained in the same manner as in Example 1 except that Nippon Seika Co., Ltd.) was added so that the content relative to the base paper mass was 1%.

Comparative Example 3
In the production of the base paper of Example 1, instead of a mixture of a cationic fatty acid amide and a nonionic wetting agent (trade name: Prosoft TQ-230, manufactured by Riken Green), a nonionic wetting agent (trade name: Sanmorin 11, A coated paper for rotary offset printing was obtained in the same manner as in Example 1 except that Sannopco) was added so that the content relative to the base paper mass was 1%.

  By using a base paper containing 0.1 to 10% by mass of a mixture of a cationic fatty acid amide and a nonionic wetting agent with respect to the base paper weight as the base paper of the coated paper, the occurrence of off-roll wrinkles is remarkable. In addition, since the blister generation temperature is maintained in a practically acceptable range, it can be applied as a coated paper for offset rotary printing that requires high-quality printing.

Claims (4)

  An offset rotary printing coated paper comprising at least one pigment coating layer mainly composed of a pigment and an adhesive on at least one side of the base paper, wherein the base paper is a mixture of a cationic fatty acid amide and a nonionic wetting agent. Coated paper for rotary offset printing, characterized by containing 0.1 to 10% by weight of the base paper.   The coated paper for offset rotary printing according to claim 1, wherein the base paper does not contain polyacrylamide in the base paper or contains polyacrylamide in an amount of 1% by mass or less based on the mass of the base paper.   The coated paper for offset rotary printing according to claim 2, wherein the polyacrylamide is branched polyacrylamide. The base paper contains a filler having an apparent specific gravity (based on JIS K 6220-1-2001) of 0.5 g / ml or less and an average particle diameter of 1 μm or more so that the paper ash content is 2 to 20% by mass. Item 4. A coated paper for rotary offset printing according to any one of items 1 to 3.