KR20020024778A - Off-set printing paper for newspapers - Google Patents

Abstract

PURPOSE: Provided is a newspaper paper obtained by coating, drying and calendar treatment of a surface treatment agent containing a water-soluble high polymer and an anti-slipping agent on newspaper base containing a volume expanding agent. Thus the obtained newspaper paper is excellent in printing operability and color printability. CONSTITUTION: A surface treating agent containing a water-soluble high polymer and an anti-slipping agent is coated on newspaper base containing a volume expanding agent, dried and subjected to calendar treatment such as high temperature soft nip calendar to produce newspaper paper in the range of 50 to 86 microns in thickness and 0.62 in a coefficient of friction. The water-soluble high polymer of the surface treatment agent is starch and/or starch derivatives.

Description

Offset printing paper for newspapers}

The present invention relates to a newspaper paper for offset printing excellent in color printing aptitude.

In recent years, great movements of newspaper papers include offset printing, increase in color printing surface, weight reduction, and high waste paper pulp blending.

Lightweight is rapidly progressing not only in terms of energy saving and resource saving, but also the needs of users (preventing increase of parcel delivery load due to increasing pages, reducing newspaper production costs, etc.). In 1990, lightweight newspapers (basic basis weight 43g / m ² ) accounted for 93% of the total, compared to the mainstream lightweight newspapers (basic basis weight 46 g / m ² ) in 1990.

As a problem of weight reduction, there is a problem of a decrease in paper thickness, and due to this problem, a problem of lowering of opacity, a problem of worsening of a through through, and a problem of lowering of strength are also expected. In addition, since waste paper pulp tends to decrease in volume, waste paper high blending has a negative effect on paper thickness.

As a bulky newspaper paper, Japanese Patent No. 3041297 discloses a newspaper paper containing an ester compound of a polyhydric alcohol and a fatty acid, and an alkylene oxide adduct of an ester compound of a polyhydric alcohol and a fatty acid. However, this method is effective for increasing the paper thickness, but the friction coefficient of the paper is lowered, causing paper flow and the like during printing, which is a problem in terms of printability. Further, in the embodiment of the patent, a newspaper sheet having a paper thickness of 98 to 113 µm is exemplified, but in an offset printing newspaper sheet, the paper thickness needs to be suppressed to at least 86 µm, and it is necessary to perform calendar processing for this. However, since the smoothness increases when calendering, the problem of lowering the friction coefficient becomes more remarkable.

In addition, the increase in color printing surface requires a new quality of color printing aptitude for newspaper papers, and the response is also a big problem.

It is an object of the present invention to provide an offset printing newspaper paper having a paper thickness of 50 μm or more and less than 85 μm, which is excellent in print workability and color printability, and a manufacturing method thereof.

MEANS TO SOLVE THE PROBLEM The present inventors apply | coated, dried, and calendered the surface treatment agent containing a water-soluble polymer and an anti-slip agent to the newspaper paper containing a volume expanding agent, and the paper thickness is 50 micrometers or more and less than 85 micrometers, and a dynamic friction coefficient The present invention was completed by discovering that it is possible to make the range of 0.45 to 0.62, and at the same time improving the color printability of the offset printing newspaper paper.

The present invention is obtained by applying, drying and calendering a surface treating agent containing a water-soluble polymer and an anti-slip agent to a newspaper paper containing a volume expanding agent, wherein the paper thickness is 50 μm or more and less than 85 μm, and the coefficient of dynamic friction is 0.45 to 0.62. To an offset printable newspaper paper.

Newspaper paper used in the present invention is mechanical pulp such as ground pulp (GP; ground pulp), thermomechanical pulp (TMP), chemical thermomechanical pulp (CTMP), semichemical pulp, etc. By dissociating chemical pulp represented by kraft pulp, de-inked pulp obtained by deinking waste paper containing these pulp, and damaged paper produced in the papermaking process The obtained pulp etc. which are obtained are mixed individually or in arbitrary ratios, and the volume expander mentioned later is added, and it is paper-made by the paper machine which is generally known and common. The blending ratio of DIP is more preferably in the range of 50 to 100% in view of the recent high blending flow of DIP.

Examples of the volume expander used in the present invention include ester compounds of polyhydric alcohols and fatty acids described in Japanese Patent Application Laid-Open No. 11-350380, Japanese Patent Application Laid-Open No. 2000-34691, or esters of polyhydric alcohols and fatty acids having an oxyalkylene group. Compounds, polyoxyalkylene adducts of higher alcohols described in Japanese Patent Application Laid-open No. WO98 / 03730, oil-based nonionic surfactants and sugar alcohols described in Japanese Patent Application Laid-Open No. 11-200283 Nonionic surfactants, sugar-based nonionic surfactants, specific fatty acids described in JP-A-11-200284, and polyoxyalkylene adducts of fatty acid esters, JP-A-11-200285 And combinations of specific nonionic surfactants described with specific anionic surfactants. As drugs for increasing volume (volume increasing), BASF's Ssol VL, Bayer's Bivolume P Liquid, and Japan's Huawang Co., Ltd. KB-08T, KB-08W, KB-110, KB-115, There is a chemical called Reactfake of Samchang Co., Ltd. in Japan. These volume expansion chemicals may use 2 or more types together, respectively.

Although the volume expansion agent used in the present invention is difficult to define the amount of use, since the volume expansion effect and the degree of friction coefficient reduction are different due to the influence of pulp blending, internal chemicals, etc. The base paper may be prepared by adding 0.1 to 1% by weight in the range of 0.1 to 5% by weight per absolute dry weight of the pulp to be composed.

Newspaper paper of the present invention, if necessary, white carbon, clay, silica, talc, titanium oxide, calcium carbide, synthetic resin filler (vinyl chloride resin, polystyrene resin, urea formalin resin, melamine resin, styrene / butadiene type) Copolymer-based resins). In addition, a copolymer salt of acrylamide / aminomethylacrylamide and a mineral-enhancer such as polyacrylamide polymer, polyvinyl alcohol polymer, cationic starch, urea / formalin resin, melamine / formalin resin, and Water-soluble / yield improvers such as mild starch, polyethyleneimine, polyethylene oxide, acrylamide / sodium acrylate copolymer, rosin-based sizing agent, alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA), petroleum You may contain internal additive size agents, such as a system size agent and a neutral rosin size agent, preparations, such as aluminum sulfate (sulfate band), an ultraviolet-ray inhibitor, and a fading inhibitor. In addition, the physical properties other than the coefficient of friction of the base paper of the news paper may be those of the tensile strength, tear strength, elongation, and the like of a normal news paper.

The base paper of the present invention may be a base paper of acidic paper, and may be a base paper of neutral paper or alkaline paper. The basis weight of the newspaper paper is not particularly limited, but is about 33 to 45 g / m ² .

Newspaper paper for offset printing of the present invention is obtained by applying, drying, and calendering a surface treatment agent containing a water-soluble polymer and an anti-slip agent to the paper base paper.

Examples of the water-soluble polymer used in the present invention include starch, enzyme modified starch, thermochemical modified starch, oxidized starch, esterified starch, etherified starch, cationic starch and the like, polyvinyl alcohol, fully saponified polyvinyl alcohol, Polyvinyl alcohols such as partially saponified polyvinyl alcohol, carboxyl modified polyvinyl alcohol, cyranol modified polyvinyl alcohol, cation modified polyvinyl alcohol, terminal alkyl modified polyvinyl alcohol, polyacrylamide, cationic polyacrylamide, anion And polyacrylamides such as polyacrylamide and amphoteric polyacrylamide, and celluloses such as carboxymethyl cellulose, hydroxyethyl cellulose, and methyl cellulose. These are used individually or in mixture of 2 or more types. Among these, it is preferable to use starch, and among them, oxidized starch, etherified starch and esterified starch are most preferred.

As the anti-slip agent used in the present invention, colloidal silica, alumina sol, water glass, synthetic resin particles (for example, butyl polyacrylate, polymethyl methacrylate, etc.) described in Japanese Patent Application Laid-Open No. 52-103510 Styrene / (meth) acrylic acid ester resin, the composition which consists of the coarse particle silica / colloidal silica / soft binder of Unexamined-Japanese-Patent No. 55-107597, and the colloidal silica of Unexamined-Japanese-Patent No. 61-296198, A composition consisting of a polyacrylic acid derivative or a cellulose derivative, a composition composed of styrene-butadiene copolymer latex described in JP-A-62-110997, particulate polystyrene and polyvinyl alkyl ether, JP-A-62-133199 (Meth) acrylic acid ester / polyfunctional (meth) acrylic acid ester copolymerization of Unexamined-Japanese-Patent No. 11-61688. An anti-slip agent comprising: a fine silica powder as disclosed in Japanese Patent Application Laid-Open No. H11-183596, an aluminum compound, a composition containing a water-soluble cellulose derivative, and a styrene (derivative) as described in Japanese Patent Application Laid-Open No. 2-26997; Anti-slip agent consisting of a reaction product obtained by reacting a copolymer containing a dialkylaminoalkyl (meth) acrylamide with a quaternizing agent, rice husks of rice and cereals described in Japanese Patent Application Laid-Open No. 5-263392, Japanese Laid-Open Patent Publication The colloidal silica of 6-184991, the coating composition for paper containing a silane coupling agent, the anti-slip agent which consists of the colloidal silica of JP-A-7-48800, and ethylene vinyl acetate emulsion, JP-A An anti-slip agent mainly composed of silica particles and aqueous resin emulsions described in Japanese Patent Application Laid-Open No. 7-304999; An anti-slip agent composition containing rica particles, an anti-slip treatment agent obtained by emulsion-polymerizing a specific water-soluble monomer using the cationic water-soluble polymer described in JP-A-7-82692, JP-A 9-279500 The non-slip agent for paper described in the publication, the non-slip agent for paper of the acrylic acid system described in JP-A-9-291495, and the anionic sizing agent described in JP-A-10-204792 and the specific acrylamide polymer The surface size agent which has the slipperiness | lubricacy which consists of mixed ion complexes mentioned above, the aqueous coating composition excellent in the slipperiness | lubrication property of Unexamined-Japanese-Patent No. 11-1893, etc. are mentioned. These are used individually or in mixture of 2 or more types. In addition, fillers such as silica powder, calcium carbonate, kaolin, white carbon, engineered kaolin, titanium oxide, and the like may also be used, although this is not necessarily preferable because of the cause of filing.

The surface treating agent of the present invention may contain preparations such as preservatives, antifoaming agents, anti-sticking agents, anti-UV agents, anti-fading agents, fluorescent whitening agents, viscosity stabilizers, and surface size agents within a range not affected by the present invention.

The mixing ratio (weight ratio) of the water-soluble polymer and the anti-slip agent of the surface treatment agent of the present invention may be determined depending on the quality required for the offset printing newspaper paper to be produced, but is not necessarily limited. However, if the compounding ratio is limited, the range of water-soluble polymer: anti-slip agent = 100: 0.1 to 20 is appropriate.

The coating amount of the surface treatment agent of the present invention (in other words, the total amount of solids of the water-soluble polymer and the anti-slip agent) must also be determined according to the quality of the newspaper paper for offset printing, which is also produced. 1.5 g / m ² is suitable. When the coating amount is less than 0.1 g / m ² , the effect of the surface treating agent is not sufficiently exhibited in terms of improving the surface strength or improving the coefficient of friction. On the other hand, when the application amount is higher than 1.5 g / m ² , there is a high possibility of causing so-called adhesion (stickiness). In the surface treating agent of the present invention, when the water-soluble polymer is starch, the coating amount of the surface treating agent is suitably about 0.3 to 1.2 g / m ² in consideration of the effect of improving the surface strength.

The apparatus (coating machine) for coating the surface treating agent of the present invention is not particularly limited as long as it is a conventional paper coating machine, but is, for example, a two-roll press, a blade metal ring press, and a rod metal ring press. And devices such as a gate roll coater, a bar coater, and an air knife coater. Among these devices, a film transfer type coater represented by a gate roll coater is preferable, and in the case of newspaper paper, a gate roll coater is common among these devices, and most preferably used in the present invention.

In the production of newspaper paper, the coating of the surface treatment agent generally consists of an on-machine coating machine. Therefore, the coating speed should be about the papermaking speed of a conventional newspaper paper machine, and is in the range of 800 to 1800 m / min.

Newspaper paper for offset printing of the present invention is obtained by applying a surface treatment agent and calendering in order to obtain paper thickness and smoothness suitable for offset printing. As a calendar, a normal hard nip calendar or a soft nip calendar (for example, summarized in paper pulp technique Times Vol. 43, No. 1 (2000) p23, etc.) is mentioned. In light of the weight reduction of the newspaper paper in the future, the soft nip calendar is more preferably used in the offset printing newspaper paper of the present invention. As a condition of the soft nip calendering process, it is good to use it in the range of 30-150 degreeC of temperature and 20-150 kN./m of linear pressures according to the quality (paper thickness, smoothness, etc.) of the newspaper paper requested | required. In view of color printability, the surface treating agent of the present invention may be combined with a soft nip calendering treatment.

The paper thickness of the paper for offset printing of this invention needs to be in the range of 50 micrometers or more and less than 85 micrometers. When the thickness of the paper is less than 50 µm, the strength is lowered, so that the paper is cut off on the rotary press, or the quality such as strike through is degraded. If the paper thickness is 85 μm or more, the stiffness becomes high, and workability at the bend of the web is deteriorated.

The coefficient of kinetic friction of the newspaper paper for offset printing according to the present invention needs to be in the range of 0.45 to 0.62. If the coefficient of kinetic friction is less than 0.45, there may be a problem of a paper flow problem or a problem of lowering the printing tension. On the other hand, when the dynamic friction coefficient is higher than 0.62, the problem of deterioration of the running property of a paper, etc. is worried.

Although the color printing aptitude of the newspaper paper for offset printing of this invention does not have a suitable evaluation method regarding a color printing aptitude, it cannot be specifically limited, However, what is necessary is just to have good printing surface when it is printed with a real color printing machine.

(Action)

By applying, drying, and calendering a surface treatment agent containing a water-soluble polymer and an antislip agent to a newspaper paper containing a volume expanding agent, an offset printing newspaper paper having excellent color printability can be obtained.

Although it is still unclear why the color printability is good, the paper layer is advantageous for the colorability of the ink because a volume expander forms a suitable pore structure in the paper, and a non-slip agent imparts particles of a suitable particle size to the paper surface layer. It may be because the structure is formed.

EXAMPLE

Hereinafter, although an Example demonstrates this invention, this invention is not limited by these Examples. In addition, in an example, a part and% represent each weight part and weight% unless there is particular notice. The addition amount of the volume expanding agent represents the ratio per absolute dry pulp added at the time of papermaking. Therefore, it is not the ratio of component A which exists in newspaper paper.

The following were obtained about the volume expander, water-soluble polymer, and anti-slip agent used by this invention.

<Volume expanding agent>

A-1: pentaerythritol monostearate (Japanese Patent Publication No. 3041297 Example)

A-2: stearic acid monoglyceride (Japanese Patent Publication No. 3041297 Example)

A-3: Sucrose monooleate (Japanese Patent Publication No. 3041297 Example)

A-4: Product Name KB-08W (花王 Co., Ltd. product)

A-5: Brand name KB-115 (花王 Co., Ltd. product)

<Water-soluble polymer>

B-1: Oxidized Starch

B-2: hydroxyethylated starch (trade name: PG-280, manufactured by Penford)

<Antislip agent>

C-1: Styrene-based non-slip agent (brand name: BT-1, Arakawa Chemical Industries, Ltd.)

C-2: Silica Slip Resistant (Brand Name: NS-603, Somal Co., Ltd.)

C-3: Acrylic Anti-Slip Agent (Brand Name: Hamacoat G-280, Misawa Ceramics Co., Ltd. product)

C-4: Calcium Carbonate Slip Resistant (Trade Name: Tsnex E, Shiroishi Kogyo Co., Ltd.)

EXAMPLES 1-4

Cationized starch per absolute dry pulp (trade name: CATO) in a pulp slurry prepared by mixing and dissociating at a ratio of 60 parts of DIP (180 ml of freeness), 30 parts of TMP (100 ml of freeness), and 10 parts of NBKP (600 ml of Freedom degree). -302, Nippon NSC Co., Ltd., 0.5%, rosin-based sizing agent (trade name: N-773, Arakawa Chemical Co., Ltd.), 0.2%, and a volume expanding agent at the addition rate shown in Table 1, After the papermaking pH was adjusted to 4.5 with aluminum sulfate, papermaking was carried out with an experimental orientation paper machine to obtain newspaper paper. The surface treatment agent which consists of the water-soluble polymer and the anti-slip agent shown in Table 1 was apply | coated and dried to the felt surface of this newspaper paper base material using a Mayer bar. Subsequently, the super calender treatment was performed so that paper thickness might be 50 micrometers or more and less than 85 micrometers, and newspaper paper for offset printing was produced.

The following paper quality was evaluated about the obtained offset printing newspaper paper, and the result is shown in Table 1.

Basis weight: According to ISO536-1976.

Paper thickness: According to ISO534-1988 (JIS P8118).

Dynamic friction coefficient: Based on JIS P 8147.

Comparative Example 1, 3 to 5

In the same manner as in Examples 1 to 4, except that the surface treatment agent shown in Table 1 containing no anti-slip agent was applied to the felt surface of the original paper paper sheet produced in Example 1 using a maya bar. Prepared. The paper quality mentioned above was evaluated about the obtained offset printing newspaper paper, and the result is shown in Table 1.

Comparative Example 2

When papermaking was carried out with an experimental oriented paper machine, a newspaper paper for offset printing was produced in the same manner as in Comparative Example 1 except that 3% of white carbon was added per absolute dry pulp. The paper quality mentioned above was evaluated about the obtained offset printing newspaper paper, and the result is shown in Table 1.

Comparative Example 6

When papermaking with an experimental orientation paper machine, a newspaper paper for offset printing was produced in the same manner as in Comparative Example 1 except that no volume expanding agent was added. The paper quality mentioned above was evaluated about the obtained offset printing newspaper paper, and the result is shown in Table 1.

TABLE 1

Component Type A Addition Rate (%) Component B Component C Compounding ratio (B: C) Coating amount (one side, g / m ² ) Basis weight (g / m ² ) Paper thickness (μm) Dynamic friction coefficient Example 1 A-1 0.5 B-1 C-1 100: 5 0.24 40.3 73 0.53 Example 2 A-2 0.5 B-1 C-2 100: 8 0.34 40.9 72 0.56 Example 3 A-3 2 B-2 C-3 100: 15 0.33 42.5 81 0.51 Example 4 A-4 0.25 B-1 C-4 100: 0.3 0.29 40.1 73 0.53 Comparative Example 1 A-1 0.5 B-1 - 100: 0 0.23 40.2 74 0.38 Comparative Example 2 A-1 0.5 B-1 - 100: 0 0.26 40.5 74 0.39 Comparative Example 3 A-2 0.5 B-1 - 100: 0 0.35 40.7 78 0.39 Comparative Example 4 A-3 2 B-2 - 100: 0 0.36 42.7 88 0.20 Comparative Example 5 A-4 0.25 B-1 - 100: 0 0.27 40.4 74 0.38 Comparative Example 6 - 0 B-1 - 100: 0 0.26 40.5 65 0.50

As shown in Examples 1 to 4 of Table 1, a paper thickness suitable for an offset printing newspaper paper was applied by applying a surface treatment agent containing a water-soluble polymer and an anti-slip agent to a newspaper paper containing a volume expanding agent and drying it, followed by a calender treatment. The above-mentioned quality which is less than 85 micrometers and whose dynamic coefficient of friction is 0.45-0.62 was obtained. On the other hand, in Comparative Examples 1 to 5 in which a surface treatment agent containing only a water-soluble polymer was applied to a newspaper paper containing a volume expanding agent, the coefficient of friction was less than 0.45, which is unsuitable as a newspaper paper for offset printing.

[Examples 5 to 8]

50 parts of DIP (180 ml of free), 35 parts of TMP (100 ml of free), 10 parts of NBKP (600 ml of Freedom), and 5 parts of GP (80 ml of Freedom) to disperse and prepare pulp slurry prepared by mixing and dissolving pulp Mild starch (brand name: CATO-302, Japan NSC Co., Ltd.) 1.0%, alkyl ketene dimer (brand name: AS263, Japan PMC Co., Ltd.) 0.06%, sulfate band 1.5%, calcium carbonate 2.0% as filler A-5 was added at the addition rate shown in Table 2 as a volume expanding agent, and the surface treatment agent containing the water-soluble polymer and the anti-slip agent shown in Table 1 was prepared on a machine using a Velveformer type paper machine at a papermaking speed of 1050 m / min. Gate roll coating was carried out, and a high-temperature soft nip calendering process (roll temperature of 110 ° C., linear pressure of 180 kN / m) made the paper thickness for offset printing using a paper thickness of 50 μm or more and less than 85 μm and smoothness suitable for offset printing.

The offset printing newspaper papers of Examples 5 to 8 were evaluated for the above items and the color printability shown below, and the results are shown in Table 2.

Evaluation of color printability: Color four-color printing (in order of navy blue, red, yellow, and black) is performed using an offset rotary press (TOSHIBA offset rotary press: 0A-4B2T-600), and the fourth index black solid portion , And the density | concentration evaluation of the superposition color part which superimposed four colors, and density | concentration staining were visually evaluated.

(Double-circle): The density of the 4th index black is very high, and there is no density unevenness. Moreover, a very uniform image is obtained in the superposition color part.

(Circle): The face density of the 4th index black is high, and there is little density unevenness. In addition, a uniform image is obtained in the superposed color portion.

(Triangle | delta): The face density of the 4th index black is slightly low, and density | concentration unevenness is recognized. In addition, an image that is nonuniform in the overlapping color portion and slightly poor in sharpness is obtained.

X: The face density of the 4th index black is low, and density | concentration unevenness is also recognized clearly. In addition, an image having nonuniformity and lack of sharpness in an overlapping color portion is obtained.

Example 9

In Example 5, a newspaper paper for offset printing was produced in the same manner as in Example 5 except that the calendering treatment was a hard nip calendering treatment (five stages of 4 nips, a roll temperature of 60 ° C, and a linear pressure of 35 kN / m). The paper quality of the same items as Example 5-8 was evaluated about the obtained offset printing newspaper paper, and the result is shown in Table 2.

[Comparative Examples 7-9]

At the time of gate roll coating, as shown in Table 2, except for coating with a surface treatment agent containing no anti-slip agent, newspaper paper for offset printing was produced in the same manner as in Examples 5 to 8. The paper quality of the same items as Example 5-8 was evaluated about the obtained offset printing newspaper paper, and the result is shown in Table 2.

Comparative Example 10

Except not adding the volume expanding agent, a newspaper paper for offset printing was produced in the same manner as in Comparative Example 7. The paper quality of the same items as Example 5-8 was evaluated about the obtained offset printing newspaper paper, and the result is shown in Table 2.

TABLE 2

Component Type A Addition Rate (%) Component B Component C Compounding ratio (B: C) Coating amount (one side, g / m ² ) Basis weight (g / m ² ) Paper thickness (μm) Dynamic friction coefficient Color printability Example 5 A-5 0.25 B-1 C-1 100: 7 0.56 40.4 74 0.58 ◎ Example 6 A-5 0.5 B-1 C-1 100: 7 0.58 40.4 75 0.57 ◎ Example 7 A-5 0.5 B-1 C-1 100: 7 0.57 40.1 72 0.53 ◎ Example 8 A-5 0.75 B-1 C-1 100: 10 0.55 40.6 70 0.49 ◎ Example 9 A-5 0.25 B-1 C-1 100: 7 0.56 40.4 70 0.59 ◎-○ Comparative Example 7 A-5 0.25 B-1 - 100: 0 0.55 40.5 73 0.41 ○ to △ Comparative Example 8 A-5 0.5 B-1 - 100: 0 0.54 40.5 72 0.33 ○ to △ Comparative Example 9 A-5 0.75 B-1 - 100: 0 0.58 40.7 70 0.22 ○ to △ Comparative Example 10 - 0 B-1 - 100: 0 0.55 40.4 66 0.54 △

As shown in Examples 5 to 9 of Table 2, a paper thickness suitable for an offset printing newspaper paper was coated by applying a dry surface treatment agent containing a water-soluble polymer and an anti-slip agent to a newspaper paper containing a volume expanding agent and drying it, followed by calendering. Quality of 50 µm or more and less than 85 µm and dynamic friction coefficient of 0.45 to 0.62 was obtained, and color printability was also excellent. On the other hand, in Comparative Examples 7 to 9 in which a surface treating agent containing only a water-soluble polymer was applied to a newspaper paper containing a volume expanding agent, the coefficient of friction was less than 0.45, which is unsuitable as an offset printing newspaper paper, and the color printing aptitude was slightly inferior. The comparative example 10 (normal offset printing newspaper paper) which apply | coated the surface treatment agent containing only a water-soluble polymer to the newspaper paper which does not contain a volume expander was inferior to the color printability.

Applying, drying, and calendering a surface treatment agent containing a water-soluble polymer and an antislip agent to a newspaper paper containing a volume expanding agent has an effect of obtaining an offset printing newspaper paper having excellent color printability.

Claims (3)

For offset printing in which paper thickness obtained by applying, drying, and calendering a surface treating agent containing a water-soluble polymer and an antislip agent to a newspaper paper containing a volume expanding agent is 50 μm or more and less than 85 μm, and the coefficient of dynamic friction is in the range of 0.45 to 0.62. Newspaper. The newspaper sheet for offset printing as claimed in claim 1, wherein the calendar treatment is a high temperature soft nip calendar treatment. The newspaper paper for offset printing according to claim 1 or 2, wherein the water-soluble polymer of the surface treating agent is starch and / or starch derivative.