JP2002317397A - Coated paper for offset printing using environment- friendly ink and deinkable printed matter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coated paper for offset printing, compatibly exhibiting excellent ink setting property and printing gloss on the printing by using the environment friendly ink, and an deinkable printed matter from which the ink is easily removed when the printed matter is recycled as regenerated paper. SOLUTION: The coated paper has one layer of a coated layer on one side or both the sides of a base paper. In the coated paper, 25 wt.% or more of the pigment contained in the coated layer comprises kaolin having particle sizes of 2 μm or less in 94 wt.% or more, and the pigment has a smoothness determined by Smooster, an air micrometer-type smoothness tester, of 1.5 kPa or less and an air permeability of 0.30 kPa of more. Further, the coated paper for environment friendly ink-using offset printing has two or more layers of coated layers. Furthermore, the deinkable printed matter is obtained by offset printing on the coated paper by using an environment friendly ink containing a plant-derived oil in an amount of 20 wt.% or more based on the whole ink.

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 printing for environmentally friendly inks and an easily deinkable printed matter, and more particularly to the use of a relatively large amount of plant-based oil in place of petroleum-based solvent. When using so-called environmentally friendly inks, it has excellent ink setting properties and print gloss,
The present invention relates to a coated paper for offset printing for environment-friendly ink, which is easy to deink when processed as recycled paper, and a printed material with easy deinking properties.

[0002]

2. Description of the Related Art In recent years, in the field of offset printing and its printed matter, demands for print operability and print quality have become increasingly severe. On the other hand, reducing the burden on the environment is attracting attention as a major theme.

[0003] Offset printing inks use petroleum-derived solvents as raw materials. The component ratio of general ink is about 30% of petroleum solvent, about 5% of vegetable oil for rotary printing, and about 10% for sheet for the total amount of ink, and the others consist of pigments, resins, auxiliaries, etc. . Among these raw materials, volatile organic compounds (hereinafter abbreviated as VOCs) are contained in a large amount in petroleum solvents, and volatilize into the atmosphere, leading to pollution of the printing work environment and air pollution due to exhaust.
Attempts have been made to replace petroleum solvents with other raw materials in view of consuming petroleum, which is a limited natural resource.

[0004] For example, by the work of the American Soybean Association,
Use of soybean oil as a substitute for petroleum solvents is encouraged. By using more than a certain ratio, about 7% or more for rotary printing and about 20% or more for sheets, this is certified as soybean oil ink and used. Promotes.

Further, as an attempt to almost completely eliminate VOCs, inks in which all petroleum solvents are replaced with waste oils of vegetable oils or edible oils have been developed and sold. Such environmentally friendly offset printing inks not only reduce VOCs, but also provide a stable supply of resources and protect limited petroleum resources because they are derived from crops or food waste oils, and have a deinking property. It is reported to be superior to conventional petroleum solvent-intensive inks in terms of facilitating paper regeneration due to ease.

However, the weak points of such an environmentally friendly offset printing ink are the slow ink setting property and the low printing gloss. Petroleum solvents help to develop excellent ink setting properties due to their volatility. On the other hand, since the environmentally friendly ink contains little or no organic solvent, it takes a longer time for drying to proceed with the ink setting by polymerization of oil rather than evaporation. In particular, in a rotary printing press operated at high speed with forced hot air drying, the problem of poor ink drying properties tends to be a problem. Further, in many cases, the printing gloss, which is regarded as important as the aesthetic performance of the printed matter, is poor.

[0007] Regarding printing using environmentally friendly ink,
Some attempts have been made in terms of ink design as a method for improving the printing operability and quality, but no report has been found on printing paper.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a printing method using so-called environmentally friendly ink, which uses a lot of vegetable oil, which tends to have poor ink setting properties and print gloss.
It provides coated paper for offset printing for environmentally friendly ink that provides both excellent ink setting properties and print gloss, and easily deinkable printed matter that can be easily deinked when processed as recycled paper. is there.

[0009]

Means for Solving the Problems As a result of intensive studies on the above-mentioned problems, the present inventor has found that the smoothness and the air permeability of the coated paper for offset printing are within a certain range, and the specific uppermost layer is It has been found that, by containing kaolin having a particle size distribution, excellent ink setting properties and print gloss are exhibited even when a so-called environmentally friendly ink using a large amount of vegetable oil is used.

[0010] That is, the coated paper for offset printing for environmentally friendly ink according to the first invention is a coating paper for offset printing for environmentally friendly ink in which one coating layer is provided on one or both sides of the base paper. In the paper, 25% by weight or more of the pigment contained in the coating layer is kaolin having a particle size of 2 μm or less of 94% by weight or more, and is smoothed by an air micrometer type smoothness tester Smooster. 1.5 degrees
It is characterized by being not more than kPa and having an air permeability of not less than 0.30 kPa.

Further, the coated paper for offset printing for environment-friendly ink according to the second invention is an offset printing paper for environment-friendly ink having two or more coating layers on one or both sides of a base paper. In the coated paper, at least 25% by weight of the pigment contained in the uppermost layer of the coating layer is kaolin having a particle size of 2 μm or less of 94% by weight or more, and a second kaolin adjacent to the uppermost layer. 40% by weight of the pigment contained in the coating layer
The above is calcium carbonate, and the smoothness of the air micrometer type smoothness tester Smooster is 1.5
It is characterized by being not more than kPa and having an air permeability of not less than 0.35 kPa.

Further, the easily deinkable printed material according to the first and second aspects of the present invention is characterized in that the content ratio of plant-derived oil in the offset printing coated paper for environmentally friendly ink is 20% by weight based on the total ink. % Or more, which is characterized in that the printed matter is printed by offset printing using an environmentally-friendly ink of not less than%.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The coated paper for offset printing for eco-friendly ink and the easily deinkable printed matter of the present invention will be described below in detail.

A first aspect of the present invention is that the base paper is provided with one coating layer on one side or both sides, and has a smoothness of 1 based on the measurement using an air micrometer type smoothness tester smoother. 0.5 kPa or less and air permeability of 0.30 kPa or more, so that even if a so-called environmentally friendly ink using a lot of vegetable oil is used, excellent ink setting properties and print gloss are exhibited. It is coated paper for offset printing.

There are roughly three drying mechanisms for drying the offset printing ink. The first is the mechanism by evaporation of petroleum-derived solvent by forced hot air drying, the second is the mechanism by which a relatively low-viscosity solvent or oil permeates the coating layer and the capillary of the base paper, and the last is vegetable oil. The mechanism is that the unsaturated double bond contained in the molecular structure of the drying oil is oxidized to form a network-like crosslinked structure. In both cases, the ink has a function of fixing the ink on paper by thickening the ink which originally has fluidity and solidifying it through immobilization.

Some of these three mechanisms work in combination, but in sheet printing, the penetration of solvent and oil and oxidative polymerization play an important role in drying the ink, and the speed is relatively high. slow. On the other hand, in the rotary printing, all of these three mechanisms operate. However, because of the fact that a large amount of printing is performed at a high speed with forced hot air drying, the setting property of the ink by evaporation of the petroleum solvent is the most important. It can be said to indicate a role.

In any case, the setting of the ink is an important factor that affects the operability of the printing press. In the case of the combination of the ink and the paper having the poor ink setting, contamination of the printing press and the printed matter by the ink is difficult. It causes problems such as solvent odor or adhesion of printed matter.

The so-called environmentally friendly ink, which uses a relatively large amount of vegetable oil, which has recently attracted attention in terms of the printing work environment, reduction of air pollution, ease of deinking, protection of petroleum resources, and the like, has its weak points. It is mentioned that ink setting property is slow and printing gloss is low.

Since the ink setting property in a short time depends on the evaporation of the petroleum-based solvent and the penetration into the coated paper for offset printing, the ink-setting property of the environment-friendly ink having a low content of the petroleum-based solvent. It is clear that is inferior.

The term "environmentally friendly ink" as used herein refers to an ink containing 18% by weight or more of vegetable oil for sheet type and 6% by weight or more for rotary type with respect to the whole ink. If the blending ratio of vegetable oil is lower than these,
The advantages as an environmentally friendly ink as described above may be significantly impaired.

The term "vegetable oil" used herein refers to soybean oil, rapeseed oil, tung oil, castor oil, linseed oil, and furthermore, their polymerized oils and modified products.

The coated paper for offset printing for environmentally friendly inks of the present invention is characterized in that its smoothness and air permeability are simultaneously defined in a certain area, so that the environmentally friendly inks as previously extended can be used. It significantly improves the weaknesses of ink setting and printing gloss.

At this time, both characteristics of smoothness and air permeability are as follows:
It is most important that the smoothness is within the range defined by the present invention.
If the air permeability is lower than 0.30 kPa even if the pressure is Pa or less, good ink setting properties cannot be exhibited even if the printing gloss is excellent. In addition, even if the air permeability is 0.30 kP
When the smoothness exceeds 1.5 kPa even if it is equal to or more than a, the printed matter excellent in aesthetic appearance is compensated for by the low printing gloss, which is a weak point of the environmentally friendly ink, even though the ink setting property is excellent. Cannot be manufactured.

That is, it is the technique of compensating for the weak point of the environment-friendly ink which is inferior in the print gloss and the ink setting property only in the high smoothness and the high air permeability area, but the calendar processing in the printing paper manufacturing process. If the smoothness is pursued by, for example, the coating layer and the base paper are compressed, the air permeability is impaired. Conversely, if the air permeability is pursued by reducing the calendering treatment, the smoothness is impaired.

As a result of our intensive studies, in order to achieve such a balance between smoothness and air permeability, among pigments contained in the coating layer of coated paper for offset printing, particles having a particle size of 2 μm or less are used. It has been found that kaolin having a diameter of 94% by weight or more needs to be 25% by weight or more.

By containing the above-mentioned fine kaolin in a certain ratio or more, the coating layer in contact with the ink has more fine holes. The fine holes play an important role in the mechanism of ink drying, and strongly promote the penetration of solvents and oils into the coated paper for offset printing, and as a result, the ink setting property is improved. In addition, such fine kaolin significantly enhances the microscopic smoothness of the coated paper for offset printing, and greatly improves the appearance of ink gloss.

In the first invention, the coating amount of the coating layer provided on one or both sides of the base paper is ^{2 to} 25 g / m ² , preferably 5 to 20 g / m ² .

Further, the coated paper for offset printing for environment-friendly ink according to the second invention is the same as that of the first invention, wherein the second coating layer adjacent to the uppermost layer is provided with the coating. The pigment contained in the layer contains 40% by weight or more of calcium carbonate, and has a smoothness of 1.5 kPa or less as measured by using an air micrometer type smoothness tester Smooster. The temper needs to be 0.35 kPa or more.

Here, the calcium carbonate preferably has an average particle diameter of 2.5 to 1.0 μm, and may be either natural or artificial. The calcium carbonate used does not exist in the uppermost layer of the coated paper for offset printing of the present invention, but exists as an intermediate layer close to the uppermost layer, thereby improving the ink setting property without impairing the printing gloss. Mainly demonstrate. Therefore, the coated paper for offset printing for environmentally friendly ink shown in the second invention is the first coated paper.
While maintaining good ink gloss as shown in the invention of
Furthermore, extremely excellent ink setting properties are exhibited. Further, in offset rotary printing involving forced hot-air drying, it also exhibits a function of improving blister resistance due to its excellent air permeability.

In the present invention, the method of applying each coating layer including the lowermost layer and the uppermost layer is not particularly limited, and various metallized film transfer such as size press, gate roll, and shim sizer, air Each method such as a knife, a rod, a blade, and a direct fountain is appropriately used.

In the second invention, when two or more coating layers are provided on one or both sides of the base paper, the coating amount of the uppermost layer is as follows:
^{2 to} 25 g / m ² , preferably 5 to 20 g / m ² ,
And the coating amount of the second coating layer close to the top layer is
It is 1 to 20 g / m ² , preferably ² to 15 g / m ² .

In the first and second aspects of the present invention, the other pigments used in the coating liquid are not particularly limited. For example, various kinds of purified natural mineral pigments such as kaolin, talc, pulverized calcium carbonate, etc. Sachin white,
Examples include composite synthetic pigments such as lithophone, semi-synthetic pigments such as titanium oxide, precipitated calcium carbonate, and alumina hydroxide, and synthetic 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.

As binders other than starch used in the coating solution, 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 waterproofing agent, and a coloring agent, and cations of these 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 is size-pressed with no-size press base paper, starch, polyvinyl alcohol, or the like can be used. Various calendering processes may be performed to obtain the required density and smoothness of the base paper.

In a series of operations, the coated and dried coated paper is subjected to various calender treatments as necessary.

Further, the third invention is characterized in that the content ratio of plant-derived oil to the coated paper for offset printing for environmentally friendly inks shown in the first and second inventions selected in this manner is reduced. It is an easily deinkable printed material consisting of a printed material that has been offset-printed using an environment-friendly ink that is 20% by weight or more with respect to all inks.

The environment-friendly ink according to the present invention is an ink containing the above-described vegetable oil in an amount of 20% by weight or more, and is applied to the coated paper for offset printing according to the first and second inventions. The deinking effect on the printed material is improved.

Here, the production process of the deinked pulp can be broadly divided into two processes, namely, disintegration and peeling of the ink by a pulper, and removal of the ink by a floater and purification of the pulp. The coated paper for offset printing according to the first and second aspects of the present invention contains a relatively large amount of kaolin having a small particle diameter in its coating layer. Facilitates destruction and promotes deinking. Furthermore, if there are two or more coating layers as in the second invention, the coating layer can be easily separated in the pulper process.

Therefore, the printed matter according to the third aspect of the present invention realizes better printing workability due to superior ink setting properties than the combination of the conventional offset printing coated paper and the environmentally friendly ink, and The present invention provides a printed material having excellent aesthetic performance with excellent print gloss, and in addition, the printed material exhibits excellent deinking properties when preparing deinked pulp. Therefore, it can be said that the printed matter is a significant printed matter that promotes the demand for recycled paper.

[0044]

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 percentages in the examples are by weight unless otherwise specified.

<< First Invention >> Examples 1-4 and Comparative Examples 1-3 Coated papers for offset printing of Examples 1-4 and Comparative Examples 1-3 were prepared with the following formulations. <Base paper composition> LBKP (freeness 330 to 440 mlcsf) 70 parts NBKP (freeness 390 to 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 described above Adjusted by blending, basis weight 70g /
the base paper of m ² and papermaking.

To this base paper, 0.30 g / m ² of oxidized starch was adhered by a size press to obtain a base paper for coating.

<Composition of coating liquid> Commercial kaolin clay * The types and the number of parts are shown in Table 1. Commercial heavy calcium carbonate 20 to 80 parts Commercial polyacrylic acid-based dispersant 0.1 part Latex binder 15 parts Commercial phosphoric acid Esterified starch 3 parts Commercially available carboxymethylcellulose-based thickener (CMC) 0.1 part Adjusted to pH 9.6 with sodium hydroxide

The coated papers for offset printing prepared in Examples 1 to 4 and Comparative Examples 1 to 3 were evaluated by the following evaluation methods. The results are shown in Table 1. The environmentally friendly ink used in the evaluation was a sheet offset ink in which the blending ratio of vegetable oil was 20% by weight with respect to all inks.

<Evaluation method> (1) Ink setting property After printing a sample with a fixed amount of ink using an RI printing suitability tester, a coating for offset printing prepared separately was provided at intervals of 30 seconds. The image was transferred to paper, and the degree of transfer was visually evaluated (a maximum of 10 points). Here, を or more was the subject of the invention. ◎ (very good): 10 points ○ (good): 7 to 9 points △ (normal): 4 to 6 points × (bad): 5 points or less

(2) Printing Gloss Using a RI printing suitability tester, after applying solid printing of indigo, red, and yellow (each ink amount: 0.2 cc), the gloss was measured with a gloss meter at an incident angle of 60. The evaluation was made based on the reflectance at a reflection angle of 60 °. The evaluation criteria are shown below. Here, を or more was 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%

[0052]

[Table 1]

Evaluation: In all of Examples 1 to 4, both excellent ink setting property and printing gloss are compatible at a high level.
On the other hand, in Comparative Examples 1 to 3, it can be seen that both the ink setting property and the print gloss are inferior because the weak points in the quality of the environment-friendly ink are exhibited.

<< Second Invention >> Examples 5 to 7 and Comparative Examples 4 and 5 Coated papers for offset printing of Examples 5 to 7 and Comparative Examples 4 to 5 were prepared with the following formulations. <Base paper composition> LBKP (freeness 330 to 440 mlcsf) 70 parts NBKP (freeness 390 to 490 mlcsf) 30 parts

<Internally added chemicals> Light calcium carbonate (* expressed 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 Undercoating Liquid> Commercially available primary kaolin clay (proportion of particle size 2 μm or less 93%) 20 to 90 parts Commercially available heavy calcium carbonate 10 to 80 parts Commercially available polyacrylic acid dispersant 0.1 part Latex binder 8 Part Commercially available phosphorylated starch 8 parts Commercially available carboxymethylcellulose-based thickener (CMC) 0.1 part Adjusted to pH 9.6 with sodium hydroxide

The base paper was coated with 5.0 g / m ² of the above undercoat liquid by a film press coater to obtain a base paper for coating.

<Blending of Overcoating Liquid> 30 parts of commercially available fine kaolin clay (particle ratio of 2 μm or less: 98%) 30 parts of commercial primary kaolin clay (93% of particle diameter of 2 μm or less) 20 parts commercially available heavy calcium carbonate 50 parts commercially available poly Acrylic acid dispersant 0.1 part Latex binder 15 parts Commercial phosphorylated ester 3 parts Commercial carboxymethyl cellulose thickener (CMC) 0.1 part Adjusted to pH 9.6 with sodium hydroxide

Further, a coating solution having the above ratio was prepared, and using a fountain application / blade type coating machine, the coating solution was coated at 11 g on one side at a coating speed of 1600 m / min.
/ m ² and dried to obtain a coated paper.

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

The coated papers for offset printing prepared in Examples 5 to 7 and Comparative Examples 4 to 5 were evaluated by the following evaluation methods. The results are shown in Table 2. The evaluation methods of the ink setting property and the print gloss are the same evaluation methods as described above.

<Evaluation method> (1) Blister resistance The coated paper for offset printing wrapped with aluminum was immersed in an oil bath at 150 ° C. to 200 ° C. for a certain period of time, and scored according to the number and size of the generated blisters. (Out of 10). Here, を or more was the subject of the invention. ◎ (very good): 10 points ○ (good): 7 to 9 points △ (normal): 4 to 6 points × (bad): 5 points or less

[0063]

[Table 2]

Evaluation: From Example 5 to Example 7, as the proportion of the heavy calcium carbonate in the undercoat increases, the air permeability increases and the ink setting property becomes better. In addition, the blister resistance has also been improved. On the other hand, in Comparative Examples 4 and 5, it can be seen that only normal blister resistance can be obtained.

<< Third Invention >> Examples 8 to 11 and Comparative Examples 6 to 13 As described below, easily deinkable prints of Examples 8 to 11 and Comparative Examples 6 to 13 were produced. In addition, the coating paper for offset printing used for printing was represented by each symbol as shown below. Printing paper A: Coated paper for offset printing prepared in Example 1 Printing paper B: Coated paper for offset printing prepared in Example 6 Printing paper C: Coated paper for offset printing prepared in Comparative example 1 D: Coated paper for offset printing prepared in Comparative Example 4

The printing papers A to D described above were printed by a sheet offset printing machine using the following environment-friendly inks. Eco-friendly ink a: 10% by weight of vegetable oil to all inks Eco-friendly ink b: 20% by weight of vegetable oil to all inks Eco-friendly ink c: 40% by weight of vegetable oil to all inks

Examples 8 to 11 and Comparative Examples 6 to 13
Were evaluated by the following evaluation methods, and the results are shown in Table 3. The evaluation methods of the ink setting property and the print gloss are the same evaluation methods as described above.

<Evaluation Method> (1) Deinking The printed matter was subjected to a series of deinking pulp manufacturing processes such as pulper and flotation, and a sheet was prepared on a laboratory paper machine using the obtained pulp slurry. did.
The colored impurities contained in this sheet were binarized by an image analyzer, and the area and the number of the colored impurities were determined. Based on this, the deinking property was expressed on a scale of 1 to 10. Here, を or more was the subject of the invention. ◎ (very good): 10 points ○ (good): 7 to 9 points △ (normal): 4 to 6 points × (bad): 5 points or less

[0069]

[Table 3]

Evaluation: In Examples 8 to 11, the first and second
It is a combination of coated paper for offset printing for environment-friendly ink and ink containing a large amount of vegetable oil, which is applicable to the invention of the above-mentioned invention. Inks are also exhibited. In Comparative Examples 6 and 7, the ratio of the vegetable oil to the total ink was 1 in the coated paper for offset printing for the environmentally friendly ink.
It is a combination with 0% by weight of ink, and although the ink setting property and the printing gloss are good, the deinking property is slightly inferior. On the other hand, Comparative Example 8 is a combination of a coated paper for offset printing and ink having a vegetable oil ratio of 10% by weight,
Although the ink setting property and the printing gloss are good, the deinking property is very poor. In Comparative Examples 9 and 10, the proportions of the coated paper for offset printing and the vegetable oil were 20% by weight and 4%, respectively.
It is a combination with 0% by weight of ink and does not use coated paper for offset printing for environmentally friendly inks. Has not been shown much.

[0071]

The coated paper for offset printing for the environment-friendly ink according to the present invention is a case where a so-called environment-friendly ink containing a relatively large amount of plant-derived oil is used instead of the petroleum-based solvent. In addition, the ink setability and the printing gloss are excellent, and the easily deinkable printed matter is excellent in the deinking property when processed as recycled paper.

Claims (3)

[Claims] In a coated paper for offset printing for an environmentally friendly ink having one coating layer provided on one or both sides of a base paper, 25% by weight or more of a pigment contained in the coating layer is contained. A kaolin having a particle diameter of 2 μm or less of 94% by weight or more, and having a smoothness of 1.5 kPa or less and an air permeability of 0.30 kPa or more by an air micrometer type smoothness tester Smooster. Coated paper for offset printing for environmentally friendly inks. 2. In a coated paper for offset printing for environment-friendly ink having two or more coating layers provided on one or both sides of the base paper, 25% of the pigment contained in the uppermost layer of the coating layer is used.
At least 40% by weight of the pigment contained in the second coating layer adjacent to the uppermost layer is calcium carbonate; A coated paper for offset printing for environmentally friendly ink, characterized by having a smoothness of 1.5 kPa or less and an air permeability of 0.35 kPa or more by an air micrometer type smoothness tester Smooster. 3. The environment-friendly ink according to claim 1 or 2, wherein the content ratio of plant-derived oil in the coated paper for offset printing for the environment-friendly ink is 20% by weight or more based on all inks. An easily deinkable printed material, characterized in that the printed material is an offset printed material.