JP2002371492A - Coated paper for offset rotary printing resistant to delamination and method for producing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coated paper for offset rotary printing, effective for preventing the defective printing caused by delamination, having high white paper brightness and printing gloss and free from delamination trouble and provide a method for the production of the paper. SOLUTION: The coated paper for offset rotary printing free from delamination trouble has coating layers on one or both surfaces of a base paper. The coating layer contains 5-20 wt.% hollow pigment having particle diameter of >=1 μm based on the total pigment and 3-30 wt.% latex binder (based on the pigment) having a gel content of <=65% and an average particle diameter of 100-250 nm. The coated paper has an air permeability of >=1.0 kpa measured by Smooster (an air-micrometer type smoothness tester). The method for producing the coated paper comprises the application of the coating layer to the base paper and the calendaring treatment with a supercalender under a calendaring pressure of <=200 kN/cm to set the surface smoothness of the coated paper to >=1.3 μmH20 measured by Parker Print-Surf (an air-leak paper smoothness tester).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coated paper for offset rotary printing in which printing defects due to delamination are prevented and delamination having high blank gloss and printed gloss is prevented, and a method for producing the same. is there.

[0002]

2. Description of the Related Art In web offset printing presses for printing on rolled paper, a phenomenon called "delamination" in which paper is taken on a blanket cylinder may occur. This is the imbalance of the dot area ratio of the upper and lower trunk blanket,
This phenomenon is likely to occur in the case of high ink tackiness, insufficient tension in the printing press, and the like, and this phenomenon causes printing defects such as white spots and doubles on a printed image. In recent years, the gloss of coated paper for printing has been increased, and the occurrence of this printing failure has increased.

[0003] This delamination will be described with reference to FIG. FIG. 1 is an explanatory diagram showing the traveling properties of printing paper in a normal state and when delamination occurs. Printing paper 1
Is traveling from right to left, and while passing between the lower and upper body blankets 2 and 3 on the upstream side, the ink on the blanket is transferred to the printing paper 1 to print a print image of a predetermined color. After printing on the back and front sides of the paper, the printing paper reaches a downstream upper and lower blanket (not shown), where a print image of another color is printed.

Here, the reason why the upper body blanket 3 advances in the running direction of the printing paper 1 as compared with the lower body blanket 2 is called a stuck card amount, and the amount X of winding the printing paper 1 around the blanket is determined. As described above, by always winding the print paper 1 by about 5 °, the tension fluctuation when the printing paper 1 passes between the upper and lower blankets is suppressed. Accordingly, the normal running property of the printing paper is such that it runs around the upper and lower body blankets by about 5 ° as indicated by the solid line, and normal printing can be performed by maintaining the running property in this state.

On the other hand, the dotted line Y and the dotted line Z show the running state of the printing paper when delamination occurs, and the halftone dot area ratio of the lower body blanket 2 is large (the ink coverage is large). When the halftone dot area ratio of the upper body blanket 3 is small (the amount of ink is small), the printing paper 1 is pulled toward the lower body blanket 2 side, so that the dotted line indicates the running state Y when delamination occurs. Delamination occurs, and in the opposite case, the printing paper 1 is pulled toward the upper body blanket 3 side, so that a delamination such as the traveling state Z at the time of the occurrence of the delamination indicated by the dotted line occurs.

With reference to FIG. 3, a description will be given, with reference to FIG. 3, of a mechanism in which, among print defects caused by this delamination, a print defect as shown in a print image 6 in which a blank-state print defect has occurred in FIG. FIG. 3 is an explanatory diagram showing ink transferability to printing paper when delamination occurs. In FIG. 3, the halftone dot area ratio of the lower body blanket 2 is large (the amount of the lower body ink 4 is large) and the halftone dot area ratio of the upper body blanket 3 is small (the amount of the upper body ink 5 is small). On the lower cylinder blanket 2 side, the printing paper 1 is normally wound like the winding amount X around the blanket, while on the upper cylinder blanket 3 side, the printing paper 1 is pulled toward the lower cylinder blanket 2 side, and the dotted line A delamination like the running state Y at the time of the delamination occurs, and a normal winding amount cannot be maintained. as a result,
Ink transfer from the upper cylinder blanket 3 to the printing paper 1 becomes insufficient, and by proceeding with printing in this state, a small amount of ink residue 7 is generated on the upper cylinder blanket 3, and finally the ink residue 7 is deposited. Dried.

FIG. 4 shows a state in which ink residue 7 is deposited on the upper cylinder blanket and dried. FIG. 4 is an explanatory view showing an aspect in which the ink film portion is formed on the upper body blanket. As shown in FIG. 4, an ink film portion 8 due to the remaining ink is formed on the upper body blanket 3, and the ink film portion 8 is inferior to the peripheral portion in ink adhesion.
It is considered that a blank print defect occurs.

[0008] Conventionally, in order to prevent printing defects caused by such delamination, the purpose of reducing the difference in tension between the upper and lower blankets has been to reduce the viscosity of ink or increase the tension of the printing press due to the addition of additives.
In order to prevent the delamination itself, measures such as installation of an air nozzle device have been adopted.

[0009] However, when additives are contained in the ink, printing conditions such as color tone change, the tension of the printing press is increased to cause paper breakage, and a new air nozzle device or the like is used to prevent delamination itself. In addition, there are problems such as the necessity of installation of various facilities and a reduction in the work space of the printing operator.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, to prevent the occurrence of delamination, and to provide coated paper for offset rotary printing having high blank gloss and high print gloss and its production. It provides a method.

[0011]

Means for Solving the Problems As a result of intensive studies in view of the above, the present inventors have invented a coated paper for offset rotary printing which prevents the occurrence of delamination of the present invention and a method for producing the same.

[0012] The coated web for offset rotary printing of the present invention, in which delamination is prevented, is a coated web for offset rotary printing provided with a coating layer on one or both sides of a base paper, wherein particles are contained in the coated layer. A hollow pigment having a diameter of 1 μm or more is 5 to 20% by mass of all pigments, and a gel content of 65% or less,
A latex binder having an average particle diameter of 100 to 250 nm is contained in an amount of 3 to 30% by mass based on the pigment, and air permeability by an air micrometer type smoothness tester Smooster is 1.0 kpa or more. Is what you do.

The method for producing a coated paper for offset rotary printing in which the occurrence of delamination is prevented is provided by applying a coating layer on one or both sides of a base paper and then using a super calender at a calender pressure of 200 kN / cm or less. The coated paper is processed, and the surface of the coated paper is adjusted to have a smoothness of 1.3 μmH20 or more by an air leak type paper smoothness tester Parker Print Surf.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a coated paper for offset rotary printing in which delamination is prevented according to the present invention and a method for producing the same will be described in detail.

The coated paper for rotary offset printing of the present invention, in which delamination is prevented, contains a specific pigment in the coating layer, and the coated paper for rotary offset printing has a smooth air micrometer type smoothness tester. Air permeability (hereinafter may be simply abbreviated as air permeability), or the air permeability and smoothness as measured by an air leak type paper smoothness tester Parker Print Surf (hereinafter simply abbreviated as dynamic smoothness). ) To prevent the occurrence of delamination during offset rotary printing.

The occurrence of delamination during offset rotary printing is largely affected by the printing plate, ink, and printing press. However, in recent years, the number of occurrences of delamination has increased due to the increase in glossiness of printing paper.

There has not been much research on the factors that cause delamination in offset rotary printing coated paper, and no knowledge has been found so far.

Therefore, the present inventor manufactured various coated papers for offset rotary printing, and examined the relationship between the coated papers and the occurrence of delamination. As a result, it was found that the occurrence of delamination is strongly related to the air permeability of the coated paper for offset rotary printing, preferably air permeability and dynamic smoothness.

The air permeability described here is the air permeability (unit: air micrometer type smoothness tester smoother).
kpa). This is a value indicating how easily the coated paper for offset rotary printing allows air to pass through. The larger the value, the easier the air passes.

The dynamic smoothness is determined by the smoothness (unit:
μmH20). Here, the “dynamic smoothness” is not simply “smoothness” indicating the smoothness of the coated web for offset rotary printing, but the smoothness when pressure is applied to the coated web for offset rotary printing. It is the smoothness shown.

Since the printing pressure is applied to the offset rotary printing paper by the blanket cylinder during the offset rotary printing, the influence of the offset rotary printing coating paper at the time of printing can be reduced by adopting the above-mentioned dynamic smoothness. Reflect well.

In the present invention, the air permeability and dynamic smoothness are as follows:
It has a great effect on the air flow between the web offset printing press and the blanket cylinder. Offset rotary printing coated paper with high dynamic smoothness easily adheres to the blanket cylinder like a suction cup. In a portion where the density of the printing ink is high, such as a solid printing portion, the printing ink fills the fine unevenness, so that it becomes easier to adhere. In addition, if the coated paper for web offset printing is difficult to pass through the air, it is difficult for the coated paper that is in close contact to peel off from the blanket cylinder.

Therefore, it can be said that coated web for offset rotary printing having high air permeability and low dynamic smoothness is a very effective means for preventing the occurrence of delamination.

One of the important factors that determine the air permeability of the coated paper for web offset printing in the present invention is the gel content of the latex binder.

The "gel content" of the latex binder as used herein indicates the proportion of a portion insoluble in an organic solvent such as toluene or benzene, and indicates the degree of crosslinking of the polymer constituting the latex binder. It is.

If the gel content is reduced, the air permeability of the coating layer in the offset rotary printing coated paper is improved. However, on the other hand, print characteristics such as print gloss tend to decrease.

As with the gel content, the average particle size of the latex binder is also a factor that has a great influence on air permeability and print gloss.

The “average particle size” of the latex binder referred to herein is a mean value obtained by observing the Brownian motion of the latex binder in water by a dynamic laser light scattering method and analyzing the value by a photon correlation method such as a time interval method. It is a particle diameter, and a unit is nm.

When the average particle diameter of the latex binder contained in the coating layer applied to the web for offset rotary printing in the present invention is small, the air permeability decreases and the printing gloss decreases. To rise. On the other hand, when the average particle diameter is large, the opposite behavior is exhibited.

That is, in the coated paper for offset rotary printing of the present invention, the gel content and the average particle diameter of the latex binder are mutually specified to a specific value, so that the offset rotary printing can be performed at a very high level which has not been achieved conventionally. The present invention is characterized in that the air permeability of a coating layer of a printing coated paper is increased.

The coated paper for offset rotary printing of the present invention contains a latex binder having a gel content of 65% or less and an average particle diameter of 100 to 250 nm in a coating layer provided on one or both sides of the base paper. By doing so, excellent air permeability can be exhibited.

Here, when the gel content is larger than 65% or when the average particle size is less than 100 nm, the intended air permeability cannot be obtained. On the other hand, when the average particle diameter is larger than 250 nm, the dry pick strength is reduced, which may cause a reduction in workability of offset rotary printing, which is not preferable.

The amount of the latex binder is 3 to 30% by mass, preferably 5 to 30% by mass, based on the pigment in the coating layer.
25% by mass. Here, when the compounding amount of the latex binder is less than 3% by mass, the adhesion to the pigment is poor,
If it exceeds 30% by mass, air permeability is impaired, which is not preferable.

Examples of latex binders include various copolymer latexes of styrene-butadiene type, acrylic type, vinyl acetate type and the like. Specifically, trade name P9505 (Japan A & L), trade name 2600B (J
SR), trade name L-1608.01 (Asahi Kasei), trade name F8B (Zeon) and the like.

Further, in the present invention, excellent printing gloss can be imparted by incorporating a hollow pigment having a particle diameter of 1 μm or more in the coating layer in an amount of 5 to 20% by mass of all pigments. As a result, it is possible to simultaneously exhibit, at a high level, two characteristics that are difficult to achieve at the same time only by designing a latex binder, that is, excellent air permeability and print gloss.

Here, when the particle size of the hollow pigment is less than 1 μm, the air permeability of the coating layer is poor, which is not preferable. Also,
If the content of the hollow pigment with respect to all the pigments is less than 5% by mass,
Although air permeability is inferior, on the other hand, even if the content exceeds 20% by mass, the effect of extreme air permeability is not obtained, and saturation is reached, which is not efficient.

Examples of the hollow pigment include various polymerization or copolymers such as a polystyrene type and a styrene butadiene type. Specific examples thereof include HP-91 (trade name) (R & H),
A product name such as AE-850 (JSR) can be exemplified.

Next, a method for producing a coated paper for rotary offset printing in which delamination is prevented according to the present invention will be described below.

The method for producing a coated paper for web offset printing in the present invention is as follows. A coating layer is coated on one or both sides of the base paper, and the coated paper is coated with a super calender at a calender pressure of 200 kN / cm or less. The paper is calendered, and the surface of the coated paper is made to have a smoothness of 1.3 μmH20 or more by an air leak type paper smoothness tester Parker Print Surf.

That is, a paper having a particle size of 1 μm
m and a latex binder having a gel content of 65% or less and an average particle size of 100 to 250 nm, respectively, in an amount of 5 to 20% by mass of the total pigment and 3 to the pigment.
After providing a coating layer containing up to 30% by mass, the surface of the coated paper is calendered under a condition of 200 kN / cm or less using a super calendering apparatus, and the surface of the coated paper is smoothed by an air leak type paper smoothness tester Parker Print Surf. (Dynamic smoothness) This is a method for producing a coated paper for rotary offset printing with 1.3 μm H20 or more.

In the present invention, when a coating layer is formed on the base paper surface and calendering is performed under specified conditions, it corresponds to the flow of air between the coated paper and the blanket cylinder during offset rotary printing. The desired dynamic smoothness is obtained. Here, when the calender pressure is higher than 200 kN / cm, the dynamic smoothness is increased and the above-described air permeability is decreased, and the balance between the air permeability and the dynamic smoothness is lost and delamination occurs. Result.

In general, calendering is a very important means in the production of coated paper, by which the quality of the coated paper can be determined. In particular, in the case of coated paper such as gloss paper, a gloss type coated paper having high white gloss can be obtained by treating with a high calender pressure to enhance smoothness.

In the coated web for offset rotary printing of the present invention, the air permeability of the coated web for offset rotary printing is maintained only under such calender pressure by the effect of the latex binder contained in the coating layer. In addition, by adding a hollow pigment, it provides a coating layer with very easy gloss of white paper gloss, eliminating the need to apply unnecessary pressure, high air permeability, and high dynamic smoothness I do.

Further, the occurrence of delamination has a strong hardware factor, and the higher the air permeability of the coated web for offset rotary printing, the better, and the lower the smoothness, the lower the dynamic smoothness. The higher the better. Therefore, the coated paper for offset rotary printing of the present invention is also effective for coated paper for mat or rotary offset rotary printing.

In the present invention, the method of applying the coating layer is not particularly limited, and various metallized film transfers such as a size press, a gate roll, a shim sizer, an air knife, a rod, a blade, a direct fountain, etc. The method is used as appropriate.

In the present invention, the pigment used in the coating liquid is not particularly limited, and examples thereof include purified kaolin, talc, refined natural mineral pigments such as pulverized calcium carbonate, and composites such as satin white and lithopone. Examples include synthetic pigments, semi-synthetic pigments such as titanium oxide, precipitated calcium carbonate, and alumina hydroxide, and synthetic resin pigments such as plastic pigments.

Examples of the starch used in the coating liquid include ordinary starch, oxidized starch, etherified starch, esterified starch, enzyme-modified starch, and cold-water-soluble starch obtained by flash-drying them. Can be

As the thickener used in the coating solution, carboxymethyl cellulose, sodium alginate,
Water-soluble polymers such as methylcellulose, hydroxyethylcellulose, casein, and sodium polyacrylate; synthetic polymers such as polyacrylate and styrene-maleic anhydride copolymer; and inorganic polymers such as silicate.

Examples of binders other than starch used in the coating solution include various copolymer latexes such as styrene-butadiene, acrylic and vinyl acetate, polyvinyl alcohol, sodium polyacrylate, polyethylene oxide, polyacrylamide, urea. Or melamine /
Examples include water-soluble compounds such as formalin resin, polyethyleneimine, polyamide polyamine / epichlorohydrin, natural products such as wax, casein and soybean protein, and cationized products thereof.

If necessary, various commonly used auxiliaries such as a dispersant, an antifoaming agent, a water-proofing agent and a coloring agent, and cations of these various auxiliaries are preferably used. .

The base paper used in the present invention is LBK.
Chemical pulp such as P, NBKP, GP, PGWRMP,
Including mechanical pulp such as TMP, CTMP, CGP and various pulp such as waste paper pulp, various fillers such as light calcium carbonate, heavy calcium carbonate, talc, clay, kaolin, etc., sizing agent, fixing agent, retention agent, paper strength Various compounding agents such as an enhancer can be suitably compounded, and the paper can be made in any of acidic, neutral and alkaline conditions.

As the base paper of the present invention, a base paper which has been size-pressed with a no-size press base paper, starch, polyvinyl alcohol or the like can be used. In addition, various types of calendering may be performed to obtain the required density and smoothness of the base paper. In a series of operations, the coated and dried coated web for offset rotary printing is subjected to various calendering processes as necessary.

[0053] In the present invention, the coating amount, as dry weight, 1 to 40 g / m ^2, preferably 2 to 30 g / m ²
It is.

In the present invention, the amount of the latex binder contained in the coating layer is usually 1 to 30 parts by mass, preferably 3 to 20 parts by mass, based on the total mass of the pigment.

In the present invention, the layer structure of the coating layer is not particularly limited to a single layer.
It may be a coating layer having more than two layers.

[0056]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples. All parts and% in the examples are parts by mass and% by mass unless otherwise specified.

Example 1 <Blend of base paper> LBKP (freeness 440 mlcsf) 70 parts NBKP (freeness 490 mlcsf) 30 parts

<Internally added chemicals> Light calcium carbonate (* indicated by ash content in base paper) * 8 parts Commercially available cationized starch 1.0 part Commercially available cationic polyacrylamide retention aid 0.03 parts Pulp and internal additives are as described above. Adjusted by blending, basis weight 70g /
the base paper of m ² and papermaking.

<Blending of Coating Liquid> Commercially available hollow pigment (particle size: 1 μm) 5 parts Commercially available fine kaolin clay 45 parts Commercially available primary kaolin clay 20 parts Commercially available heavy calcium carbonate 30 parts Commercially available polyacrylic acid dispersant 0.1 part Latex binder 10 parts Commercially available phosphate ester starch 5 parts Sodium hydroxide adjusted to pH 9.6 A coating solution was prepared for the base paper obtained as described above by the above blending, and using a fountain application / blade type coating machine. The coating solution was applied at a coating speed of 1600 m / min on one side at 15 g / m ² and dried to obtain a coated paper.

The obtained coated paper was subjected to an off-line super calendering apparatus (10 steps, rigid roll: chilled roll having an outer diameter of 400 mm, elastic roll: outer diameter of 400 m).
m, a calendering treatment was performed using a cotton roll with a linear pressure of 220 kg / cm) to produce a coated paper for offset rotary printing of Example 1.

Examples 2 to 10 and Comparative Examples 1 to 5 The blending number of the hollow pigment with respect to 50 parts by weight of the total blending amount of the commercially available hollow pigment and the commercially available fine kaolin clay in Example 1, the gel content of the latex binder and the average particle Coated papers for offset rotary printing of Examples 2 to 10 and Comparative Examples 1 to 5 were produced in the same manner as in Example 1 except that the diameter was as described in Table 1.

The coated paper for web offset printing obtained in Examples 1 to 10 and Comparative Examples 1 to 5 was evaluated by the following evaluation methods. The results are shown in Table 1.

<Evaluation Method> (1) Air Permeability Air permeability was measured with a smoother air micrometer type smoothness tester. The unit is kpa.

(2) Gloss on White Paper Gloss was measured at an angle of 75 degrees according to JIS P-8142. The evaluation criteria are shown below. However, in the present invention, objects of ○ or more are included in the invention. ◎ (very good): blank paper gloss is 75% or more ○ (good): blank paper gloss is 65% or more and less than 75% △ (normal): blank paper gloss is 55% or more and less than 65% × (bad): blank paper gloss Is less than 55%

(3) Delamination A printing test was carried out using a Lithopia rotary offset printing press, and the resulting printing defects were visually judged and evaluated. ○ The above was the subject of the invention. A: No occurrence. ：: Almost no occurrence was observed. Δ: Slight occurrence. ×: Occurred.

[0066]

[Table 1]

Evaluation: In Examples 1 to 10, the air permeability was kept high and delamination was prevented by using an appropriate pigment blend satisfying the conditions of the present invention, a gel content and a latex binder having an average particle diameter. ing. When the number of hollow pigment parts is 10 or more, the glossiness of white paper is very high (Examples 2 to 4). However, even below that, the effect of preventing the delami ghost is sufficient (Example 1). If the particle size of the latex binder is the same, the air permeability is kept higher as the gel content is lower (Examples 3, 5 to 7), and if the gel content is the same, the air permeability is higher as the average particle size is higher. The degree is kept high (Examples 3, 8 to 10). In any case, delamination is prevented because of maintaining the air permeability satisfying the conditions of the present invention. On the other hand, in Comparative Examples 1 to 5, since one or both of the gel content and the average particle size of the latex binder contained are not within the specified ranges, the air permeability cannot be kept high, and deami ghost occurs. Has been done.

Examples 11 to 15 Table 2 shows the blending number of the hollow pigment, the gel content of the latex binder and the average particle diameter with respect to 50 parts of the total blending amount of the commercially available hollow pigment and the commercially available fine kaolin clay in Example 1. As described, the coated paper for offset rotary printing of Examples 11 to 15 was prepared in the same manner as in Example 1 except that the dynamic smoothness was described as a condition of the calender pressure of the coated paper described in Table 2. Manufactured.

The coated paper for web offset printing obtained in Examples 11 to 15 was evaluated by the above evaluation method and the following evaluation methods of printing gloss and dynamic smoothness. The results are shown in Table 2. Was.

<Evaluation Method> (1) Printing Gloss After using a RI printing suitability tester to perform solid printing of indigo, red and yellow (each ink amount: 0.2 cc), the gloss was measured by a gloss meter. Was evaluated by 60 ° -60 ° reflectance.
The evaluation criteria are shown below. However, in the present invention,
The above is the subject of the invention. ◎ (very good): print gloss is 70% or more ○ (good): print gloss is 65% or more and less than 70% Δ (normal): print gloss is 55% or more and less than 65% × (bad): print gloss Is less than 55%

(2) Dynamic smoothness Measured by Parker Print Surf, an air leak type paper smoothness tester. The unit is μmH20.

[0072]

[Table 2]

Evaluation: In Examples 11 to 15, in addition to the condition of claim 1 in the claims of the present invention, claim 2
By satisfying the above condition, delamination is more effectively prevented. In Example 12, since the gel content was low, and in Example 13, the printing gloss was lower than that in Example 11 due to the large particle size. However, a good level was still maintained due to the effect of the hollow pigment. Example 1
Even in Nos. 4 to 15, the same level of white paper gloss as the coated paper containing no hollow pigment as in Comparative Examples 1, 3, and 5 was maintained.

[0074]

As described above, the coated paper for offset rotary printing of the present invention contains a specific hollow pigment and a latex binder in a coating layer, and is transparent by an air micrometer type smoothness tester Smooster. By defining the temper,
High white paper gloss can be obtained and delamination can be prevented.Furthermore, it is manufactured by processing with a specific calender pressure, and the air leak type paper smoothness tester Parker Print Surf is used for offset rotary printing. Man-made paper has excellent printing gloss in addition to blank gloss and can further prevent delamination.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing the traveling properties of printing paper in a normal state and when delamination occurs.

FIG. 2 is a plan view showing an upper torso image in which a white spot-shaped printing failure has occurred.

FIG. 3 is an explanatory diagram showing ink transferability to printing paper when delamination occurs.

FIG. 4 is an explanatory view showing an aspect in which an ink film portion is formed on an upper barrel blanket.

[Explanation of symbols]

 Reference Signs List 1 printing paper 2 lower drum blanket 3 upper drum blanket 4 lower drum ink 5 upper drum ink 6 Printed image with blank printing failure 7 Ink remaining 8 Ink film part X Amount of wrap around blanket Y, Z Delamination occurs Running state of printing paper

Claims (2)

[Claims] 1. A coated paper for offset rotary printing wherein a coating layer is provided on one or both sides of a base paper, wherein the coating layer comprises
A hollow pigment having a particle diameter of 1 μm or more is used in an amount of 5 to 20% by mass of all pigments and a gel content of 65% or less and an average particle diameter of 100%.
3 to 30% by mass of a latex binder having a particle size of ２５０250 nm with respect to the pigment, and an air permeability of 1.0 kp by an air micrometer type smoothness tester Smooster.
a coated web for offset rotary printing wherein occurrence of delamination is prevented. 2. The method for producing coated paper for offset rotary printing wherein delamination is prevented according to claim 1, wherein a coating layer is applied on one or both sides of the base paper, and then a calender is applied using a super calendering apparatus. Pressure 200kN /
cm or less, and the smoothness of the surface of the coated paper by an air leak type paper smoothness tester Parker Print Surf is set to 1.3 μmH20 or more. Manufacturing method of coated paper for printing.