JP5332501B2 - Coated paper for printing - Google Patents

Abstract

The invention provides a coating paper for printing obtained by a twin-wire former type paper machine with excellent texture, paper interlayer intensity, rigidity and printing aptitude, characterized in that: more than 50 weight% of bleached pulp uses eucalypt material or acacia material as the raw material and the bleached pulp is pulped by gradually adding cooking liquor and subjected to many segments of bleaching processing steps. The coating paper for printing is produced by the following steps: forming a wet paper; squeezing the wet paper; drying the squeezed paper; setting more than one paint coating layer. The weighted mean fiber length of the dissociated paper pulp is 0.6-2.0mm and the fiber length distribution coefficient is 1.5-4.0 and the aspect ratio of the tensile strength of the coating paper is below 3.0.

Description

  The present invention relates to a coated paper for printing. In particular, the present invention relates to a coated paper for printing excellent in formation, inter-paper strength, rigidity, and printability.

  In general, coated paper for printing is manufactured by applying a coating liquid mainly composed of pigment and adhesive on a base paper and then drying it. Depending on the amount of coating liquid applied and the method of finishing the coated paper, Classified into coated paper, art paper, coated paper, finely coated paper, and the like. These coated papers are subjected to multicolor printing or single color printing, and are widely used as commercial printed materials such as leaflets, brochures and posters, or as publications such as books and magazines. In recent years, with the progress of visualization and colorization of printed matter, there has been an increasing demand for higher quality coated paper for printing. Printing of white paper quality such as white paper glossiness, smoothness and whiteness, and printing smoothness etc. Quality is important. In particular, flyers, pamphlets and the like among commercial printed materials have been required to have low cost and good print finishes for the purpose of advertising media. In addition, there is a need for greater efficiency by widening and speeding up paper machines for the purpose of saving labor and reducing manufacturing costs.

  By the way, as a method for producing a coated paper for printing, there are an off-machine method in which paper making and coating are performed in separate steps, and an on-machine method in which paper making and coating are simultaneously performed with one machine. Both the off-machine method and the on-machine method are gap type formers that immediately sandwich the raw material from the head box with two wires as a measure for speeding up the wire part. is there. However, when the raw material from the head box is immediately subjected to strong dehydration from both sides of the wire, there are problems such as a decrease in peel strength in the thickness direction, a decrease in yield, and the generation of pinholes due to a decrease in yield. In addition, since the raw material that has left the head box is immediately restrained by two wires, weakness in the CD direction due to fiber orientation, wrinkles that occur during offset rotary printing (hereinafter referred to as “off-roll wrinkles”). ), And means for solving these problems are disclosed.

  Specifically, a technology to improve blister resistance by controlling the dewatering rate ratio (top wire / bottom wire) until the raw material concentration between wires reaches a specific value when making the base paper of the coated paper for printing is disclosed. However, the peel strength in the thickness direction was insufficient (Patent Document 1).

  A method for producing a coated paper for offset rotary printing, which is excellent in blister resistance by applying a water-based adhesive to a base paper made by a gap former type paper machine using a size press device, is disclosed. Although the occurrence was suppressed, the effect was insufficient for suppressing the occurrence of off-ring wrinkles (Patent Document 2).

  A technology has been proposed to eliminate or reduce off-wrinkles by defining the interwinding moisture and the interlaminar strength of the base paper using a specific relational expression. To satisfy this relational expression, Although it is necessary to keep it low, there is a risk that a decrease in moisture may cause a phenomenon that the surface of the coated paper is cracked in the subsequent folding process, so-called “folding” (Patent Document 3).

  As a method for obtaining blister resistance at the time of offset rotary printing, a method for increasing the interlayer strength of the base paper has been studied, and as one of them, cation-modified starch is immersed in the paper layer to increase the adhesive strength between pulp fibers. Although the method of raising is proposed, it cannot be said that it is enough (patent document 4).

  As a method for improving the dimensional stability and blister resistance of printing paper, a technique of treating with an enzyme that does not have filter paper decomposition activity has been disclosed, but it cannot be said that both dimensional stability and blister resistance are sufficient. Literature 5, 6).

  A technology that uses pulp treated with an enzyme having xylan-degrading activity as a method to improve the smoothness, blister resistance, and stiffness of coated papers with coating compositions on base papers made with a gap former type paper machine However, the above three characteristics cannot be improved at the same time (Patent Document 7).

  As a technology to improve the strength between the paper and the paper, the opposite side of the top wire loop that engages with the bottom wire is run almost horizontally, the table equipment is placed in the top wire loop, and the raw material liquid ejected from the secondary head box Although a paper layer forming apparatus capable of performing both papermaking and single layer papermaking has been proposed, there is a problem that the stiffness in the CD direction is not sufficient (Patent Document) 8).

  As a technique to prevent the strength in the thickness direction of the paper after paper making, the dehydration suppression blade is upstream of the wire running direction with respect to the plane part supporting the wire and the wire surface provided on the wire entry side of the plane part And an angle formed between the inclined surface and the wire gradually decreases toward the dewatering suppression blade on the downstream side in the flow direction of the paper raw material liquid. Although the technique comprised in this way is proposed, the effect is not fully exhibited (patent document 9).

  In order to improve the difference between the front and back caused by shoe press, a method of providing a coating layer after processing a base paper and / or a paper provided with an undercoat coating layer with a soft calender is disclosed. In order to obtain the product, strong processing cannot be performed, and there are operational problems such as an increase in streaks, and it has not been improved to a satisfactory level (Patent Document 10).

  In a gap type twin wire former paper machine, a technique is disclosed in which a wet press device in a gap former section dehydrates and smoothes both sides of a base paper at a predetermined ratio. Since the coated paper for offset printing obtained by this method is dehydrated from both sides of the base paper, the fine fibers in the center of the paper layer are reduced, a large amount of fine fibers are gathered in the surface layer of the paper, and the characteristic difference between the front and back surfaces is small. Become. However, there is a possibility that fine fibers may flow out from the surface of the paper, and there is a problem that the number of fine fibers with respect to the entire paper is reduced (Patent Document 11).

  In view of this, there is a strong demand for coated paper for printing having good formation, high rigidity, and printability, taking advantage of the high-speed operation of the gap former type paper machine.

Japanese Patent Laid-Open No. 11-100808 Japanese Patent Laid-Open No. 10-46492 JP 09-291490 A Japanese Patent No. 3744115 JP 10-46493 A Japanese Patent Laid-Open No. 10-46495 JP-A-10-53997 Japanese Patent Laid-Open No. 06-341091 Japanese Patent Laid-Open No. 10-292284 Japanese Patent Laid-Open No. 11-1891 Japanese Patent Laid-Open No. 11-1000078

  In the present invention, a specific tree species, a specific pulp physical property, a pulp obtained by a specific bleaching method is formed using a gap former type paper machine, has a good formation, has a high strength between papers, and has excellent rigidity and printability. A coated paper for printing is provided.

The present invention includes the following inventions.
(1) 50% by mass or more of bleached pulp used in paper stock is made from eucalyptus or acacia wood, pulped by the cooking method in which the cooking liquor is added separately, and further in a multistage bleaching process Wetted paper with a gap former type wire part, which is a manufactured bleached pulp, in which the stock is ejected from the head box between two looped wires and dehydrated with a forming roll and / or forming shoe to form a paper layer. Step of forming, step of squeezing wet paper with one or more shoe-type wet press devices in the press part, step of drying wet paper with a single-stage dryer before at least surface treatment in the dryer part And at least one side of the base paper obtained by surface treatment using a transfer-type size press device, the pigment and contact A coated paper for printing, which comprises a step of providing one or more pigment coating layers mainly composed of an agent, wherein the base paper has an apparent specific gravity of 0.5 or less measured according to JIS K 6220-1: 2001 1 to 30% by mass of filler having a molar extinction coefficient of 5.0 or more according to Lambert-Beer's law and an average particle size (50% volume integrated particle size measured with a laser diffraction particle size distribution meter) of 1 μm or more The pulverized pulp JAPAN TPPI No. obtained by disaggregating the printing coated paper by the pulp disaggregation method described in JIS P 8220: 1998. The weight weighted average fiber length measured by the pulp fiber length test method in the optical automatic measurement method defined in 52: 2000 is 0.6 to 2.0 mm, and the fiber length distribution coefficient is 1.5 to 4.0. The freezing degree of the disaggregated pulp measured in accordance with JIS P 8121: 1995 is 250 to 500 ml, and the tensile strength of the coated coated paper measured in accordance with JIS P 8113: 2006 is A coated paper for printing having an aspect ratio of 3.0 or less.

(2) The coated paper for printing according to (1), wherein the aspect ratio of the tensile strength of the coated paper for printing is 1.3 to 3.0.

(3) The coated paper for printing according to claim 1 or 2, wherein the final nip of the press part is a roll press and the preceding stage is a shoe press.

  The coated paper for printing according to the present invention is a coated paper in which a pulp obtained by a specific tree species, a specific disaggregation pulp property, and a specific bleaching method is formed using a gap type former, and a coating layer is provided. However, the formation is good, the strength between the paper layers is strong, the rigidity and the printability are excellent.

Details of the present invention will be described below.
The raw material of the pulp used in the present invention may be any of hardwood, softwood and non-wood, but 50% by mass or more of the pulp used for the base paper must be made from eucalyptus or acacia. I must. Eucalyptus materials include E.C. camaldulensis, E .; citriodora, E .; deglupta, E.I. globulus, E.I. grandis, E .; maculata, E .; punctata, E .; saligna, E .; terericornis, E .; urophylla and the like, and hybrids thereof, and Acacia materials include A. auracocarpa, A. et al. auriculiformis, A. et al. catech, A .; classiccarpa, A.M. decurrens, A.M. holoserica, A.M. leptocarpa, A.M. Maidenii, A.M. mangium, A.M. mearnsi, A.M. melanoxylon, A.M. nerifolia, A.M. Silvestris etc. and these hybrids are mentioned. Pulp made from eucalyptus wood and acacia wood has a small fiber width and is indispensable for developing the paper properties of the present invention.

  As the cooking method for obtaining the pulp used in the present invention, known cooking methods such as kraft cooking, polysulfide cooking, soda cooking, alkali sulfite cooking, etc. can be used. It needs to be cooked. By adding the cooking liquor in a divided manner, the alkali concentration in the entire cooking can be kept low, the elution of hemicellulose in the material is suppressed, and as a result, a pulp with a high hemicellulose content is obtained. The use of a high pulp is also an indispensable factor for the paper properties of the present invention. The cooking method is not particularly limited as long as it is a cooking method in which the cooking liquid is added in portions. However, cooking methods such as the Lo-solids method, the Compact cooking method, and the Kobudomari cooking method are manufactured with a small amount of energy used during cooking. It is preferably used in terms of incidental effects such as good bleaching properties of pulp.

  For example, when the kraft cooking method is used, the degree of sulfidation of the cooking liquor is 5 to 75%, preferably 15 to 45%, and the effective alkali addition rate is 5 to 30% by weight, preferably 10 to 25% by weight, based on the mass of absolutely dry wood. The cooking temperature is 130 to 170 ° C., and the cooking method may be either a continuous cooking method or a batch cooking method.

  In cooking, a known cyclic keto compound as a cooking aid in the cooking solution to be used, for example, benzoquinone, naphthoquinone, anthraquinone, anthrone, phenanthroquinone and quinone-based compounds such as alkyl, amino, or the like, or the quinone-based compound One kind selected from hydroquinone compounds such as anthrahydroquinone which is a reduced form of 9,10-diketohydroanthracene compound which is a stable compound obtained as an intermediate of anthraquinone synthesis method by Diels Alder method Or 2 or more types may be added and the addition rate is 0.001-1.0 mass% per the absolute dry mass of a material.

  In this invention, the unbleached pulp obtained by the well-known cooking method is delignified by the well-known alkaline oxygen bleaching method through a washing | cleaning, a rough selection, and a selection process. This is because delignification by the alkaline oxygen bleaching method can reduce the amount of bleaching chemicals used in the subsequent multistage bleaching process, and can minimize degradation of pulp quality. As the alkaline oxygen bleaching method used in the present invention, a known medium concentration method or a high concentration method can be applied as it is, but a medium concentration method which is currently used at a pulp concentration of 8 to 15% is widely used. preferable.

  In the alkali oxygen bleaching method by the medium concentration method, caustic soda or oxidized kraft white liquor can be used as the alkali. As the oxygen gas, oxygen from a cryogenic separation method, PSA (Pressure Swing Adsorption) Oxygen, oxygen from VSA (Vacuum Swing Adsorption), etc. can be used. The oxygen gas and alkali are added to a medium-concentration pulp slurry in a medium-concentration mixer. After sufficient mixing, the oxygen gas and alkali are sent to a reaction tower capable of holding a mixture of pulp, oxygen, and alkali for a certain period of time under pressure. Ligned.

  The oxygen gas addition rate is 0.5 to 3% by mass per mass of dry pulp, the alkali addition rate is 0.5 to 4% by mass, the reaction temperature is 80 to 120 ° C., the reaction time is 15 to 100 minutes, and the pulp concentration Is 8 to 15%, and other known conditions can be applied. In the present invention, in the alkaline oxygen bleaching step, it is a preferred embodiment that the alkali oxygen bleaching is continuously performed a plurality of times and delignification proceeds as much as possible.

  The pulp that has been subjected to alkaline oxygen bleaching is then sent to a washing step. After washing, the pulp is sent to a multistage bleaching process.

  In the multistage bleaching step for obtaining the bleached pulp used in the present invention, it is preferable to use the ozone bleaching stage (Z). This is because by using the ozone bleaching stage, hexeneuronic acid contained in a large amount in the pulp from eucalyptus wood and acacia wood can be decomposed, and the color return of the pulp due to hexeneuronic acid can be suppressed. The treatment conditions of the ozone bleaching stage are not particularly limited, but when ozone is excessively reacted, the pulp strength is impaired. Therefore, the ozone addition rate is preferably 0.1 per mass of the dry pulp. It is -1.0%, More preferably, it is 0.3-0.7%. The treatment temperature is 10 to 100 ° C., preferably 20 to 70 ° C., the treatment time is 1 second to 60 minutes, preferably 10 seconds to 5 minutes, and the treatment pH is 1.5 to 7, preferably 2 to 4. The pulp concentration in the ozone bleaching stage may be medium or high and is not limited. If necessary, chlorine dioxide and other bleaching chemicals can be used in combination.

  The bleaching stage that can be used in the multistage bleaching process of the present invention is not particularly limited, and a known bleaching stage can be used. Known bleaching stages include chlorine dioxide bleaching stage (D), alkali extraction stage (E), oxygen bleaching stage (O), hydrogen peroxide bleaching stage (P), peracid bleaching stage (PA), acid washing stage (a ), Acid treatment stage (A) and the like. Examples of the multi-stage bleaching process include ZEPD, ZEDP, ZEPP, AZPEPD, and AZED. -P, A-Z-E-P-AP, a-Z-E-P-D, a-Z-E-D-P, a-Z-E-P-AP, Z / D-E-P -D, Z / D-E-D-P, Z / D-E-P-AP, A-ZD-E-P-D, A-Z / D-E-D-PA-Z / DE -P-AP, a-Z / D-E-P-D, a-Z / D-E-D-P, a-Z / D-E-P-AP, Z-EO-P-D, Z -EO-DP, Z-EO-P-AP, AZ-EO-PD, AZ-EO-DP, AZ-EO-P-AP, a-Z-EO -P-D, a-Z-EO-DP, a-Z-EO-P-AP, Z / D-EO-PD, Z / D-EO-DP, Z / D-EO -PA A-ZD-EO-PD, AZ / D-EO-DP, AZ / D-EO-P-AP, aZ / D-EO-PD, a-Z / D-EO-DP, a-Z / D-EO-P-AP, D-E-P-D, D-E-D-P, D-E-P-AP, A-D-E -P-D, A-D-E-D-P, A-D-E-P-AP, a-D-E-P-D, a-D-E-D-P, a-D-E -P-AP, D-EO-PD, D-EO-DP, D-EO-P-AP, AD-EO-PD, AD-EO-DP, A -D-EO-P-AP, a-D-EO-PD, a-D-EO-DP, a-D-EO-P-AP, etc. It can also be provided. Further, a bleaching stage can be further added, or another bleaching stage can be incorporated in the bleaching stage and used together, and is not particularly limited. The pulp after multistage bleaching is sent to a beating process or a papermaking process.

  In the present invention, the wire part is not particularly limited in model, but the raw material that comes out of the head box developed to enable operation at a high speed of 1000 m / min or more is immediately used with two wires. It is a gap-type former that is sandwiched, and further performs initial dewatering with a suction blade, curvature shoe and roll. Initial dehydration with a forming roll having a good yield is preferred. Also, the press part needs to have at least one shoe-type wide nip for improving sheet dryness. In the gap type former, the raw material that has exited the head box is immediately sandwiched between two wires, so that dehydration from both wire surfaces is possible, and the lack of dewatering capacity associated with higher speeds can be compensated. In addition, it is possible to eliminate the free surface of the raw material on the wire, change the dehydration pressure applied to the raw material between the wires, and greatly improve the formation of the base paper.

However, if strong dehydration is performed immediately from the low-concentration raw material that exits the head box on both wire surfaces, the retention on the wet paper layer decreases, the peel strength in the thickness direction of the paper decreases, and the fiber orientation The problem that the property becomes strong is likely to occur. For this reason, coated paper for printing manufactured using a base paper made with a paper machine having such a gap type former in the wire part is offset in comparison with those using a base paper such as a conventional long web former. There is a drawback that blister troubles and wrinkle troubles are likely to occur when printed on a rotary printing press.
In addition, the wet press device with a shoe-type wide nip is a gentle dewatering with a wide width, and the movement of fibers to the dewatering side during dehydration is reduced, and compared with the conventional roll type press, Since the density difference in the central part tends to be small, the surface strength and the rigidity are liable to decrease.

  In the present invention, using the above-mentioned specific raw materials, using the bleached pulp produced in the cooking step and the bleaching step as described above, the weight-weighted average of the disaggregated pulp obtained by disaggregating the coated paper for printing By adjusting the fiber length and fiber length distribution coefficient, taking advantage of the high-speed operation characteristics of the gap type former and the wet type press machine with a shoe type wide nip, the reduction in retention, which is a drawback of the gap type former, The present inventors have found a method for improving a decrease in peel strength in the thickness direction of paper, fiber orientation, and a decrease in surface strength and stiffness, which are disadvantages of a wet press apparatus having a shoe-type wide nip.

In other words, taking advantage of the characteristics capable of high-speed operation in a wet press machine having a gap type pharma and a shoe type wide nip, the former and the wet press have the disadvantages of reduced retention and peeling strength in the paper thickness direction. In order to improve the decrease, fiber orientation, surface strength, and rigidity, the weight-weighted average fiber length of the disaggregated pulp obtained by disaggregating the printing coated paper is 0.6 to 2.0 mm. It is necessary to be 0.6 to 1.5 mm. Further, 0.6 to 1.2 mm is more preferable, and 0.6 to 1.0 mm is extremely preferable. When the weight-weighted average fiber length of the disaggregated pulp is less than 0.6 mm, the bonding area between the fibers is small, and the gap type former is insufficient in strength, so that the paper is easily peeled.
On the contrary, when the weight-weighted average fiber length of the disaggregated pulp exceeds 2.0 mm, the texture is deteriorated. Therefore, when offset rotary printing is performed, wrinkles are easily generated due to shrinkage stress due to hot air drying.

In the present invention, the fiber length distribution coefficient of the disaggregated pulp obtained by disaggregating the coated paper for printing needs to be 1.5 to 4.0, preferably 1.5 to 3.0, and further 1 It is more preferable that it is 0.5 to 2.5, and it is very preferable that it is 1.5 to 2.0. When the fiber length distribution coefficient of the disaggregated pulp is less than 1.5, there are few fibers having different fiber lengths that strengthen the paper interlayer bond, and the interfiber bond area becomes small and the strength becomes insufficient.
In addition, when the fiber length distribution coefficient of the disaggregated pulp exceeds 4.0, long fibers and fine fibers increase and the texture deteriorates. Therefore, when web offset printing is performed, wrinkles are likely to occur due to shrinkage stress due to hot air drying. .

Here, the fiber length distribution coefficient is a numerical value obtained by dividing the weight weighted average fiber length (W) by the number average fiber length (M), and is a value obtained by the following equation.
Fiber length distribution coefficient = weight-weighted average fiber length (W) / number average fiber length (M)
The larger the fiber length distribution coefficient, the wider the fiber length distribution, and the smaller the fiber length distribution coefficient, the narrower the fiber length distribution. The weight-weighted average fiber length and the number average fiber length are those of JAPAN TAPPI No. It is a value measured by an optical automatic measurement method defined in 52: 2000.

The coated paper for printing of the present invention preferably has a freeness of 250 to 500 ml according to JIS P 8121: 1995 of the disaggregated pulp obtained by disaggregation by the pulp disaggregation method described in JIS P 8220: 1998. . More preferably, it is 300-400 ml.
When the freeness of the disaggregated pulp is less than 250 ml, the pulp fiber of the coated paper is composed of a base paper with weak aggregates, and the bonding force between the fibers is small and the paper is easily peeled off. On the other hand, when the freeness of the disaggregated pulp exceeds 500 ml, wrinkles are likely to occur due to shrinkage stress due to hot air drying in the case of offset rotary printing. This is because when the base paper having a freeness of disaggregated pulp of more than 500 ml is made, the pulp fibers in the base paper are not uniformly dispersed, and the base paper is composed of strong aggregates of pulp fibers, and the formation is poor. Since shrinkage unevenness due to hot air drying occurs, wrinkles are likely to occur.

  The weight-weighted average fiber length, fiber length distribution coefficient, and freeness of the disaggregated pulp from the above coated paper for printing are the weight-weighted average fiber length, fiber length distribution coefficient, and filterability of the pulp used in the production of the base paper. It does not necessarily match the water level. This is because some of the fine fibers are removed from the wire mesh or net when the base paper is manufactured, and the aggregation state of the pulp fibers changes depending on the conditions in the wire part, press part, and dryer part (drying process). In the preparation process until it is sent to the wire part, in order to improve the strength between the paper layers, or to improve the yield and formation, a beating method and / or various internal additives are added to the pulp fiber. This is to adjust the size and / or shape of the floc formed between each other.

  Since the base paper used in the present invention has adjusted the weight-weighted average fiber length, fiber length distribution coefficient, and freeness of the disintegrated pulp from the printing coated paper within a specific range, the paper interlayer strength is strong, the rigidity, Excellent printability.

(Manufacture of base paper)
The base paper used in the present invention takes advantage of the characteristics capable of high-speed operation in a wet press apparatus having a gap type former and a shoe type wide nip, and reduces the retention, paper thickness, which is a disadvantage of the gap type former. Disaggregation obtained by disaggregating the coated paper for printing in order to improve the decrease in the peel strength in the direction, the fiber orientation, and the decrease in surface strength and stiffness, which are disadvantages of the wet press device having a shoe-type wide nip. The pulp is controlled to the weight-weighted average fiber length, fiber length distribution coefficient, and freeness of the specific range. Specifically, it can be produced by making paper by the following method.

In the present invention, the weight of the pulp used as a raw material is adjusted in order to adjust the freeness, weight-weighted average fiber length, and fiber length distribution coefficient of the disaggregated pulp obtained by dispersing and disaggregating the coated paper for printing again in water. The weight-weighted average fiber length and fiber length distribution coefficient are grasped and blended. Also, the freeness, weight-weighted average fiber length, and fiber length distribution coefficient are adjusted by using various internal chemicals. Further, the weight-weighted average fiber length, fiber length distribution coefficient, and freeness are adjusted also by the beating method.
As a pulp used as a raw material, it is preferable to blend 50 to 100% by mass of a pulp having a weight-weighted average fiber length of 0.5 to 1.3 mm and a fiber length distribution coefficient of 1.2 to 3.5. Preferably, 50 to 100% by mass of a pulp having a weight weighted average fiber length of 0.5 to 1.0 mm and a fiber length distribution coefficient of 1.2 to 2.2 is blended. Furthermore, it is more preferable to blend 80 to 100% by mass of the pulp.
As the internal chemical, it is preferable to use a polyacrylamide type paper strength agent having a strong cohesive force. Addition before a fan pump with a large share is more preferable.
As for the beating method, if a predetermined freeness, fiber length distribution coefficient, weight-weighted average fiber length is obtained, any of beater, Jordan, deluxe finer (DF), double disk refiner (DDR), etc. A beating machine may be used, but it is preferable to adjust the weight-weighted average fiber length and fiber length distribution coefficient by combining viscous beating and cutting beating. In particular, the weight-weighted average fiber length and fiber length distribution coefficient are adjusted by the combination of viscous beating using a beating blade with the blade width and groove width of the beating blade adjusted to be small, and cutting beating with an increased blade width and groove width. It is preferable. The degree of beating is not particularly limited as long as a predetermined fiber length distribution coefficient and a weight-weighted average fiber length can be obtained, but a treatment of about 270 to 480 ml in terms of freeness is preferable from the viewpoint of papermaking suitability.

  In this invention, it is necessary to adjust so that the aspect ratio of the tensile strength measured based on JISP8113: 2006 of the coated paper for printing may be 3.0 or less. A preferable range of the aspect ratio of the tensile strength is 1.3 to 3.0. More preferably, it is 1.3-2.5. Incidentally, if the aspect ratio of the tensile strength exceeds 3.0, the fiber orientation of the base paper constituting the coated paper for printing will be insufficiently random, the lateral stiffness will be reduced and the coated paper for printing will be turned off. In addition to the effect of suppressing the lateral propagation of the drying shrinkage force during ring printing, the effect of suppressing the generation of wrinkles is also poor.

  Here, the fiber orientation of the base paper refers to a tendency that the pulp fibers flow out onto the wire of the paper machine and are aligned in the outflow (longitudinal) direction in the process of dewatering and forming a paper layer. In other words, since the paper stock flows and dehydrates on the wire at high speed during paper making, there are many fibers oriented in the machine direction (the flow direction of the raw material on the paper machine), and the tensile strength and stiffness in the machine direction are transverse. It is considerably stronger or higher than (width direction). Presumably, the difference between the vertical and horizontal directions (anisotropy) of the base paper becomes the drying shrinkage distortion of the pulp fiber during the off-ring printing, and contributes to the wrinkles.

  In general, examples of the method for measuring the fiber orientation of paper and the like include a mechanical breaking strength method, a thermal expansion method, an X-ray diffraction method, an ultrasonic method, a microwave method, an NMR method, a polarized fluorescence method, a dielectric measurement method, and the like. It is done. In the present invention, a mechanical breaking strength method is employed, and for example, the longitudinal tensile strength and the transverse tensile strength are measured using “RTC-1210A” manufactured by Orientec Co., and the randomness of the fiber orientation is evaluated from the ratio. Is. When the aspect ratio of the tensile strength is 1.0, the fibers are completely randomly oriented. However, in the case of actual machine paper, it has some fiber orientation and cannot be reduced to 1.0 or less. .

On the other hand, since the fiber orientation is determined by the pulp used and the papermaking conditions in the machine, it is necessary to properly operate the machine. Possible means include optimization of machine speed, ratio of fiber suspension jet inflow speed to wire speed (J / W ratio), arrangement and adjustment of suction blade, curvature shoe and roll. Further, in the operation of the paper machine, the speed of the rear part is generally faster, and paper is made while pulling the paper toward the reel. When this speed difference is increased, the pulp fibers are oriented in the flow direction, so the ratio V _r / V _w of the reel rotation speed (V _r ) to the wire rotation speed (V _w ) is 1.02-1. It is preferably 07. The aspect ratio of tensile strength is controlled to 3.0 or less by combining one or more of these means.

  In some cases, the coated paper for printing according to the present invention is subjected to off-ring printing, and as a means for suppressing off-ring wrinkles and blisters at that time, the disaggregated pulp obtained by disaggregating the above-mentioned coated paper for printing The weight-weighted average fiber length is controlled to be 0.6 to 2.0 mm, the fiber length distribution coefficient is 1.5 to 4.0, and the aspect ratio of the tensile strength is 3.0 or less. In addition, by blending a filler with a specific composition and physical properties inside the paper layer of the base paper, it creates voids between pulp fibers, increases air permeability, and at the same time inhibits interfiber bonding, making it more effective off It was found that ring wrinkles and blisters can be suppressed.

  The filler internally added to the base paper is not particularly limited. For example, heavy calcium carbonate, light calcium carbonate, calcium sulfite, gypsum, talc, kaolin, calcined kaolin, delaminated kaolin, hydrated silicate , Diatomaceous earth, Magnesium carbonate, Barium carbonate, Zinc oxide, Silicon oxide, Titanium dioxide, Aluminum hydroxide, Calcium hydroxide, Magnesium hydroxide, Zinc hydroxide and other inorganic pigments, Urea / formalin resin fine particles, Organic such as micro hollow particles Pigments and the like can be exemplified, but fillers contained in waste paper and waste paper can also be reused. Two or more fillers can be used in combination.

  Among the above fillers, an apparent specific gravity of 0.5 or less measured in accordance with JIS K 6220-1: 2001 “rubber compounding agent—test method—part 1: general”, and molar absorption according to Lambert-Beer's law It is preferable to use a filler having a coefficient of 5.0 or more and an average particle diameter measured by a laser diffraction type particle size distribution meter (trade name: “MT3000”, manufactured by Nikkiso Co., Ltd.) of 1 μm or more. This is so that the weight-weighted average fiber length of the disaggregated pulp obtained by disaggregating the above-mentioned printing coated paper is 0.6 to 2.0 mm, and the fiber length distribution coefficient is 1.5 to 4.0. By placing filler between controlled pulp fibers, it is possible to effectively inhibit local aggregation of pulp fibers, further reduce off-wrinkles, and when the base paper is constructed This is because the opacity of the material is improved. As a more preferable range, a filler having an apparent specific gravity of 0.4 or less, a molar extinction coefficient of 6.0 or more, and an average particle diameter of 2 μm or more is particularly preferable. Examples of such a filler include hydrated silicate (amorphous silica such as white carbon).

Incidentally, when the average particle diameter of the filler is less than 1 μm or the apparent specific gravity exceeds 0.5, it may be difficult to obtain the effect of improving off-wrinkles. Moreover, there exists a possibility that the opacity improvement effect may become inadequate that a molar extinction coefficient is less than 5.0. Here, according to Lambert-Beer's law, if the intensity of incident light is I ₀ , the intensity of transmitted light is I, the thickness of the absorber layer is d, and the concentration of the absorber is c, log ₁₀ (I ₀ / I) = εcd, and this ε is referred to as a molar extinction coefficient. The higher the molar extinction coefficient, the higher the opacity.
The blending amount of the filler is added so as to be in the range of 1 to 30% by mass, more preferably 1 to 20% by mass. If the blending amount of the filler is less than 1% by mass, the effect of inhibiting the binding between pulp fibers is small, and it is difficult to obtain the effect of further reducing off-wrinkles. On the other hand, when the amount of the internal filler exceeds 30% by mass, the paper strength is significantly reduced.

  In addition to pulp and fillers, the paper contains internal additives such as sizing agents, anionic, nonionic, cationic or amphoteric yield improvers, drainage improvers, and paper strength enhancers. Agents can be added as needed. Specific examples of the internally added sizing agent include sizing agents such as alkyl ketene dimer, alkenyl ketene dimer, alkenyl succinic anhydride, styrene-acrylic, higher fatty acid, petroleum resin, and rosin. . Specific examples of the yield improver, drainage improver, and paper strength enhancer include, for example, polyvalent metal compounds such as aluminum (specifically, sulfate band, aluminum chloride, sodium aluminate, basic aluminum Compound), various starches, polyacrylamide, urea resin, polyamide polyamine resin, polyethyleneimine, polyamide polyamine epichlorohydrin resin, polyvinyl alcohol, polyethylene oxide and the like. Moreover, it is also possible to use a bulking agent and a softening agent having a function of inhibiting the binding between pulp fibers as long as the desired effect of the present invention is not hindered. Specific examples of bulking agents and softeners include, for example, ester compounds of polyhydric alcohols and fatty acids, polyoxyalkylene compounds of polyhydric alcohols and fatty acid ester compounds, fatty acid polyamidoamines, polyhydric alcohol surfactants, An ionic surfactant etc. can be illustrated. The amount of the bulking agent and softening agent is generally about 0.05 to 2.0% by mass with respect to the pulp.

  In the present invention, the paper layer forming apparatus is not particularly limited in model, but two sheets of raw material are immediately discharged from the head box developed to enable operation at a high speed of 1000 m / min or more. It is necessary to be a gap type former sandwiched between wires. In the gap former, the raw material exiting the head box is immediately sandwiched between two wires, so that dehydration from both wire surfaces is possible, and the lack of dewatering capacity associated with higher speeds can be compensated. In addition, it is possible to eliminate the free surface of the raw material on the wire, change the dehydration pressure applied to the raw material between the wires, and greatly improve the formation of the base paper.

  However, if a strong dehydration is performed immediately on both wire sides from the low-concentration raw material that has left the head box, there are also disadvantages such as reduced retention on the wet paper surface and reduced peel strength in the paper thickness direction. To do. Therefore, the coated paper for printing manufactured using the base paper made by a paper machine having such a gap former in the wire part is offset by rotary printing compared to the one using the base paper by the conventional long net former. When printing on a printing press, there is a drawback that blister troubles are likely to occur.

  The wet press apparatus attached to the paper machine having the gap former is not particularly limited, but one or more shoe-type wet press apparatuses can be used to meet high-speed papermaking conditions of 1000 m / min or more. is necessary.

That is, under high-speed operation conditions of 1000 m / min or more, only a conventional roll type wet press device, that is, a wet press device that passes wet paper with felt through a narrow nip formed between so-called rolls / rolls and dehydrates only, It is necessary to increase the linear pressure as the operation speed increases, and the water pressure near the roll surface increases rapidly in the nip, causing crushing between paper layers and increasing only the fiber density on the dewatered side. However, the density difference between the front and back of the base paper becomes very large, and it becomes difficult to obtain a coated paper for printing with excellent blister resistance and high printing quality. Therefore, as a wet press apparatus attached to a high-speed paper machine having a gap former as in the present invention, a wet press apparatus having one or more shoe-type wide nips has excellent blister resistance and printing quality. It is necessary for obtaining coated paper. In particular, with regard to the arrangement of the press, it is more preferable that at least the final nip is squeezed by a conventional roll press method, and the shoe press is used in the nip in the preceding stage.
As a dryer device attached to a paper machine having a gap former and one or more shoe-type wet press devices, it is arranged in a single stage at the beginning of drying at least before the surface treatment so as to be able to meet high-speed papermaking conditions of 1000 m / min or more. A mold dryer is required. That is, under high-speed operation conditions of 1000 m / min or more, when wet paper is passed through and dried with a conventional two-stage array dryer, the sheet runs out of paper or wrinkles of the sheet at the free run portion of the sheet. In addition, it becomes difficult to maintain high-speed stable running performance and quality in the width direction. Therefore, as a dryer device attached to a high-speed paper machine having a gap former and one or more shoe type wet presses as in the present invention, a single-stage array dryer is installed at least in the initial stage of drying before surface treatment. It is necessary to obtain a coated paper for printing having excellent high-speed stability and excellent printing quality.

  In the present invention, on a base paper obtained using a gap former type paper machine, using a size press machine, a size press liquid mainly composed of a synthetic adhesive such as polyacrylamide or a natural adhesive such as starch is applied to the base paper. By applying the surface treatment, the strength between the paper layers is enhanced and the blister resistance is added. In addition, as a size press apparatus attached to a gap former type paper machine and used, it is necessary to be an apparatus suitable for high speed papermaking of 1000 m / min or more.

  In other words, in a conventional two-roll type size press apparatus, which is a conventional general-purpose type, it is difficult to perform a substantially stable operation because of the dancing of the size press liquid, so-called boiling, under a high speed operation of 1000 m / min or more. Also, it is difficult to get stable quality.

  Therefore, as a size press apparatus attached to and used in a high-speed paper machine as in the present invention, a transfer type size press apparatus such as an application head metering size press is required in order to obtain operability and excellent quality. .

  When operating a high-speed paper machine and a transfer-type size press apparatus with on-machine specifications, the solid content concentration of the adhesive in the size press liquid supplied to the size press apparatus is particularly important. Is set to 2 to 12% by mass, preferably 4 to 10% by mass. Incidentally, if the solid content concentration exceeds 12% by mass, the size press solution does not sufficiently penetrate into the base paper and the effect of improving the strength between the paper layers is small. Although the penetration of paper into the base paper is promoted, the amount of size press liquid that can be penetrated is naturally limited, and as a result, the amount of adhesive in the paper layer becomes insufficient and the effect of improving the paper interlayer strength cannot be expected. It is not preferable. In addition, if the concentration of the size press solution is lowered more than necessary, the drying load of the base paper after the size press treatment increases, which is not a desirable embodiment in high-speed papermaking.

  In the present invention, the adhesive used in the size press step includes starch purified from natural plants, hydroxyethylated starch, oxidized starch, etherified starch, phosphate esterified starch, enzyme-modified starch, and flash-dried them. Cold water soluble starch, dextrin, mannan, chitosan, arabinogalactan, glycogen, inulin, pectin, hyaluronic acid, carboxymethylcellulose, hydroxyethylcellulose, and other natural polysaccharides and oligomers thereof, and modified forms thereof. Furthermore, natural polymers such as casein, gelatin, soybean protein, and collagen, and modified products thereof, and synthetic polymers and oligomers such as polylactic acid and peptides can be mentioned. In addition, each (co) polymer latex such as styrene-butadiene, acrylic, polyvinyl acetate, ethylene-vinyl acetate, polyvinyl alcohol, modified polyvinyl alcohol, sodium polyacrylate, polyethylene oxide, polyacrylamide, urea or melamine / Examples thereof include water-soluble polymers such as formalin resin, polyethyleneimine, and polyamide polyamine epichlorohydrin resin. One or more of these can be used. In addition, the use of known natural and synthetic organic compounds is not particularly limited.

  Moreover, you may add a pigment to a size press liquid as needed. Examples of the pigment include pigments for ordinary coated paper such as kaolin, barium sulfate, light calcium carbonate, heavy calcium carbonate, aluminum hydroxide, satin white, titanium dioxide, calcium sulfite, zinc sulfate, and plastic pigment. It is done. Of these, use of heavy calcium carbonate is preferable because the air permeability of the base paper can be lowered and blister trouble can be suppressed when printed on an offset rotary printing press. When a pigment is blended in the size press liquid, the blending ratio is preferably 5 to 200 parts by mass, more preferably 10 to 100 parts by mass with respect to 100 parts by mass of the pigment.

The coating amount of the size press solution is preferably about 0.5 to 13 g / m ² .

Regarding the paper making conditions of the base paper, paper is made with a gap type twin wire former, then dehydrated with one or more shoe presses, and dried at least in the initial drying stage before surface treatment with a single-stage dryer. There is no particular limitation, and any system such as acidic papermaking, neutral papermaking, or weak alkali papermaking may be used. However, in recent years, since the storage stability of paper is required, a base paper made by neutral paper making is preferable. The base paper can be subjected to a smoothing finishing process using a soft calendar or the like. The basis weight of the base paper made under these paper making conditions is preferably 30 to 150 g / m ² .

(Manufacture of coated paper for printing)
In the method for forming a coating layer of the coated paper for printing according to the present invention, at least one side of the base paper is coated with a coating liquid mainly composed of a pigment and an adhesive and dried to form one or more coating layers. It is a method which has the process of providing, and the process of performing a pressure finishing process to a base paper and a coating layer.

  In the present invention, the pigment that can be used when a coating layer is provided on the base paper is not particularly limited, for example, various natural mineral pigments such as various kaolins, talc, and heavy calcium carbonate, light calcium carbonate , Composite synthetic pigments of calcium carbonate and other hydrophilic organic compounds, satin white, lithopone, titanium dioxide, silica, alumina, aluminum hydroxide, zinc oxide, magnesium carbonate, calcined kaolin, hollow organic pigment, dense organic pigment, Examples include plastic pigments, binder pigments, plastic beads, and microcapsules. Of course, it is not limited to these.

  Adhesives used in the coating layer include starch purified from natural plants, hydroxyethylated starch, oxidized starch, etherified starch, phosphate esterified starch, enzyme-modified starch, and cold water soluble obtained by flash drying them Examples thereof include natural polysaccharides such as starch, dextrin, mannan, chitosan, arabinogalactan, glycogen, inulin, pectin, hyaluronic acid, carboxymethylcellulose, hydroxyethylcellulose, oligomers thereof, and modified products thereof. Furthermore, natural polymers such as casein, gelatin, soybean protein, and collagen, and modified products thereof, and synthetic polymers and oligomers such as polylactic acid and peptides can be mentioned. In addition, each (co) polymer latex such as styrene-butadiene, acrylic, polyvinyl acetate, ethylene-vinyl acetate, polyvinyl alcohol, modified polyvinyl alcohol, sodium polyacrylate, polyethylene oxide, polyacrylamide, urea or melamine / Examples thereof include water-soluble polymers such as formalin resin, polyethyleneimine, and polyamide polyamine epichlorohydrin resin. One or more of these can be used. In addition, the use of known natural and synthetic organic compounds is not particularly limited.

  Further, as a thickener used in the coating solution, water-soluble polymers such as carboxymethyl cellulose, sodium alginate, methyl cellulose, hydroxymethyl cellulose, casein, sodium polyacrylate, styrene-maleic anhydride copolymer, silicate, etc. And inorganic polymers.

  Furthermore, if necessary, various commonly used auxiliaries such as a dispersant, an antifoaming agent, a water-proofing agent, and a colorant, and those obtained by cationizing these various auxiliaries are suitably used.

  In the present invention, the method of coating the coating layer is not particularly limited, and includes various blade coaters such as trailing, flexible, roll application, fountain application, short dwell, size press, gate roll, and shim sizer. Various systems such as various transfer coaters, air knife coaters, bar coaters, rod coaters, rod blade coaters, champlex coaters, gravure coaters, curtain coaters, die coaters, direct fountain coaters, spray coaters, cast coaters are appropriately used. These devices may be on-machine or off-machine.

The coating amount of the coating layer is not particularly limited. For example, in the case of two-layer coating, the undercoating coating layer and the top coating layer are about 1.5 to 15 g / m ² per side in terms of dry mass, and the resulting printing is obtained. In consideration of the white paper quality, print quality and printability of the coated paper for coating, and the drying capacity at the time of producing the coated paper, the undercoat coating layer and the top coating layer are combined to 5 to 30 g / m ² per side. It is desirable to make it within a range. As a method for drying the wet coating layer, for example, various methods such as steam drying, gas heater drying, electric heater drying, infrared heater drying and the like can be adopted.

In the coated paper for printing of the present invention, a third coated layer may be formed between the base paper and a third coated layer in contact with the undercoat layer. The composition and the coating amount of the third coating layer are not particularly limited, and a coating liquid containing an arbitrary pigment and / or adhesive as a main component is 0.5 to 10 g per side in terms of dry mass. / M ² may be applied with a transfer type size press device or the like and dried.

  In the production of the coated paper for printing of the present invention, after the formation of the coating layer, it is subjected to a smoothing process in various calendar devices, such as a calendar device, a super calendar, a soft calendar, Commonly used calendar devices such as a gloss calendar, a compact calendar, a mat super calendar, and a mat calendar can be used as appropriate. As the calender finishing conditions, the temperature of the rigid roll, the calender pressure, the number of nips, the roll speed, the paper moisture before the calender, and the like are appropriately selected according to the required quality. Furthermore, the calendar device includes an off type that is different from the coater and an on type that is integrated with the coater, but can be used in either case. The material of the calendar apparatus to be used is a roll which is mirror-finished with a metal or a hard chrome plating on the surface of a rigid roll. As the elastic roll, a roll obtained by molding a resin roll such as urethane resin, epoxy resin, polyamide resin, phenol resin, or polyacrylate resin, cotton, nylon, asbestos, aramid fiber, or the like is appropriately used. In addition, it is also possible to use suitably combining the water coating apparatus, electrostatic humidification apparatus, steam humidification apparatus, etc. for humidity control and humidification of the coated paper after finishing with a calendar.

  Hereinafter, the present invention will be specifically described with reference to examples. However, the present invention is not limited to these examples. In addition, unless otherwise indicated, the part and% in an example show a mass part and the mass%, respectively. Moreover, the addition amount of the used chemical | medical agent shows the mass part of solid content conversion.

(Production of hydrated silicate (A))
According to Japanese Patent Application No. 2007-319072, 646 parts by mass of water, 138 parts by mass of a 5% strength aqueous sodium sulfate solution, and 347 parts by mass of sodium silicate No. 3 as defined in JIS K 1408-1966 were sequentially added. After stirring to a temperature of 50 ° C., the peripheral speed of the stirring blade was adjusted to 10 m / sec, and 91 parts by mass of sulfuric acid (concentration 20%) was added in 15 minutes to neutralize the first stage, The temperature was raised to 90 ° C. at the above peripheral speed. Then, 20% sulfuric acid was added at this temperature while stirring until pH 5.5, and neutralization was performed in the second stage. Next, the slurry obtained above was separated and filtered with a 200 mesh sieve to obtain a 12% by mass hydrated silicate (A) slurry.
The obtained hydrated silicate (A) was measured with a laser diffraction particle size distribution meter manufactured by Nikkiso Co., Ltd. As a result, the particle diameter of the 50% volume integrated value was 15.4 μm. Further, the transmitted light intensity of the hydrated silicate slurry diluted to a predetermined concentration was measured with a spectrophotometer to obtain the molar extinction coefficient ε (ε = 5.5).
Further, after filtering and washing the obtained hydrated silicate slurry, a part of the cake was dried at 105 ° C. and subjected to measurement of apparent specific gravity (apparent specific gravity = 0.1).

(Production of hydrated silicate (B))
According to Japanese Patent Application No. 2007-319072, 396 parts by mass of water, 666 parts by mass of a 5% strength aqueous sodium sulfate solution, and 347 parts by mass of sodium silicate No. 3 as defined in JIS K 1408-1966 were sequentially added. After stirring to a temperature of 50 ° C., the peripheral speed of the stirring blade was adjusted to 10 m / sec, and 91 parts by mass of sulfuric acid (concentration 20%) was added in 15 minutes to neutralize the first stage, The temperature was raised to 90 ° C. at the above peripheral speed. Then, 20% sulfuric acid was added at this temperature while stirring until pH 5.5, and neutralization was performed in the second stage. Next, the slurry obtained above was separated and filtered with a 200 mesh sieve to obtain a 12 mass% hydrated silicate (B) slurry.
When the obtained hydrated silicate (B) was measured with the laser diffraction particle size distribution analyzer, the particle diameter at 50% volume integrated value was 19.0 μm. Further, the transmitted light intensity of the hydrated silicate slurry diluted to a predetermined concentration was measured with a spectrophotometer to obtain the molar extinction coefficient ε (ε = 4.8).
Further, after filtering and washing the obtained hydrated silicate slurry, a part of the cake was dried at 105 ° C. and subjected to measurement of apparent specific gravity (apparent specific gravity = 0.1).

(Production of calcium carbonate slurry (A))
A calcium carbonate slurry (A) was produced by the method described in JP-A-5-163018 “Method for producing calcium carbonate”. The reaction tank was charged with 600 liters of 9.0 mass% aqueous calcium hydroxide suspension, and the dilution gas (carbon dioxide concentration: 20% by volume) was diluted with air and the flow rate was 1500 liters / minute ( (15 ° C.).

  As a means for forming fine bubbles of carbon dioxide, fine bubbles were bubbled from a small hole (round shape, diameter 20 mm, opening rate 5%) formed in a conical gas reservoir (vertical angle 90 °) at the bottom of the reaction tank. . The reaction start temperature was 42 ° C., and the reaction time was 80 minutes. The average particle diameter, molar extinction coefficient, and apparent specific gravity of the obtained calcium carbonate were 6.2 μm, 17.9, and 0.25.

(Production of calcium carbonate slurry (B))
A calcium carbonate slurry (B) was produced by the method described in JP-A-5-163018 “Method for producing calcium carbonate”. The reaction tank was charged with 600 liters of aqueous calcium hydroxide suspension having a concentration of 7.2% by weight, and the diluted gas (carbon dioxide concentration: 20% by volume) was diluted with air to a flow rate of 1500 liters / minute ( (15 ° C.).

  As a means for forming fine bubbles of carbon dioxide, fine bubbles were bubbled from a small hole (round shape, diameter 20 mm, opening rate 5%) formed in a conical gas reservoir (vertical angle 90 °) at the bottom of the reaction tank. . The reaction start temperature was 45 ° C. and the reaction time was 65 minutes. The average particle diameter, molar extinction coefficient, and apparent specific gravity of the obtained calcium carbonate were 6 μm, 17.3, and 0.3.

(Production of DIP)
Waste paper raw materials, mixed with the same amount of waste newspaper and magazine waste paper, were loaded into a high-concentration pulper and disintegrated. The raw material after disaggregation was diluted to 1%, and as a dust removal process, it was sequentially processed with a screen having a hole basket and a slit basket. Furthermore, after processing in a deinking process by a floatator (trade name: OK Floator, manufactured by Oji Engineering Co., Ltd.) and a cleaning process by an extractor, and then concentrating to 25% by a valveless thickener and a concentration process using a screw press, Add 3% hydrogen peroxide, 2% caustic soda and 2% sodium silicate, raise the temperature to 70 ° C, and perform the first dispersion using a disperser (manufactured by Aikawa Tekko Co., Ltd.) as a shaft type disperser. It was. The treated pulp was bleached for 3 hours while maintaining the temperature, and then a second dispersion treatment was performed using a disperser (manufactured by Aikawa Tekko Co., Ltd.) as a shaft type disperser.

The pulp after dispersion treatment is diluted to 1%, and further processed in a deinking process using a floatator (trade name: OK Flotator, manufactured by Oji Engineering Co., Ltd.), a washing process using an extractor, and a dust removing process using a slit basket screen. In a concentration step using a valveless thickener and screw press, the solution was concentrated to 35%. Add 1% thiourea dioxide (FAS) and 0.5% caustic soda to the concentrated pulp, raise the temperature to 110 ° C, and use the hot disperser (manufactured by KRIMA) as the disk type disperser for the third time. Was distributed. Further, it was concentrated to 10% by a washing process using an extractor and a concentration process using a valveless thickener to obtain a waste paper pulp raw material (DIP) having a whiteness of 81%, CSF of 270 ml, and impurities of 110 pieces / m ² .

<Example 1>
(Production of hardwood pulp)
Using a Lo-solids digester (manufactured by Andritz), hardwood chips composed of Acacia mangum: eucalyptus grandis = 30: 70 (mass ratio) were kraft-cooked by the Lo-solids cooking method. Here, using white liquor with a sulfidity of 28, the white liquor addition rate was divided into 10% per chip absolutely dry mass for the chip supply system, 8% for the cooking zone and 2% for the washing zone as the active alkali. And the cooking temperature was 146 ° C. After digesting the chips after cooking, unbleached pulp was obtained through a washing process, a screen process, and a washing process again.

  To the unbleached pulp, 1.7% of caustic soda and 1.8% of oxygen per mass of dry pulp were added, and two-stage alkaline oxygen bleaching was performed under the conditions of a pulp concentration of 10%, 98 ° C. for 50 minutes. Here, caustic soda was added all at once in the first stage, and oxygen gas was added in 1.0% in the first stage and 0.8% in the second stage. The pulp after alkaline oxygen bleaching was washed in the washing step.

  After 1.2% sulfuric acid was added to the pulp after the alkali oxygen bleaching, and the pulp was retained under the conditions of 10% pulp concentration, 60 ° C. and 60 minutes, it was washed in the washing step. Next, after adding 0.5% ozone and 0.5% chlorine dioxide per mass of dry pulp, medium concentration ozone / chlorine dioxide bleaching was performed at a pulp concentration of 10%, 58 ° C. for 60 minutes, followed by washing. It was washed in the process. Subsequently, 1.0% caustic soda and 0.1% hydrogen peroxide per mass of dry pulp are added, and after alkali extraction under conditions of pulp concentration 10%, 60 ° C. for 90 minutes, washing treatment is performed in the washing step. did. Finally, 0.2% chlorine dioxide is added per mass of dry pulp, and chlorine dioxide bleaching is performed under the conditions of 10% pulp density, 70 ° C, 120 minutes, and then washed in the washing step. Obtained. The ISO whiteness of the obtained bleached pulp was 90.1%. The xylan content was 13.5%.

Here, the xylan content in the bleached pulp was measured by the following method.
350 mg of absolutely dried bleached pulp was collected, 3 ml of 72% sulfuric acid was added thereto, and the mixture was stirred well, and then allowed to stand for 2.5 hours. Thereafter, 84 ml of distilled water was added and stirred well, followed by reaction at 121 ° C. for 1 hour to hydrolyze the polysaccharide of the bleached pulp to a monosaccharide. Monosaccharides were quantified using ion chromatography (DX-500, manufactured by Dionex) equipped with a column (CarboPac PA1), and the ratio of the xylose content in the total monosaccharide content was defined as the xylan content of the bleached pulp.

  Double disk refiner (blade material: Ni-Hard, blade width: 4.0 mm, groove) in which the above bleached pulp (concentration 4.2% by mass) is connected in parallel with three machines (the blades are the same) (Width: 4.0 mm) and beaten to CSF 450 ml.

(Production of softwood pulp)
Using a Lo-solids digester (manufactured by Andritz), conifer chips made of Douglas fir: radiata pine: caribbean pine = 1: 1: 1 (mass ratio) were craft-cooked by the Lo-solids cooking method. Here, using white liquor having a sulfidity of 25, the white liquor addition rate was divided into 10% per chip dry mass for the chip supply system, 8% for the digestion zone, and 2% for the cleaning zone as the active alkali. And the cooking temperature was 165 ° C. After digesting the chips after cooking, unbleached pulp was obtained through a washing process, a screen process, and a washing process again.

  To the unbleached pulp, 2.0% caustic soda and 1.8% oxygen per mass of dry pulp were added, and two-stage alkaline oxygen bleaching was performed under the conditions of a pulp concentration of 10%, 98 ° C., and 50 minutes. Here, caustic soda was added all at once in the first stage, and oxygen gas was added in 1.0% in the first stage and 0.8% in the second stage. The pulp after alkaline oxygen bleaching was washed in the washing step.

  After 1.2% sulfuric acid was added to the pulp after the alkali oxygen bleaching, and the pulp was retained under the conditions of 10% pulp concentration, 60 ° C. and 60 minutes, it was washed in the washing step. Next, after adding 0.5% ozone and 0.5% chlorine dioxide per mass of dry pulp, medium concentration ozone / chlorine dioxide bleaching was performed at a pulp concentration of 10%, 58 ° C. for 60 minutes, followed by washing. It was washed in the process. Subsequently, 1.0% caustic soda and 0.1% hydrogen peroxide per mass of dry pulp are added, and after alkali extraction under conditions of pulp concentration 10%, 60 ° C. for 90 minutes, washing treatment is performed in the washing step. did. Finally, 0.2% chlorine dioxide is added per mass of dry pulp, and chlorine dioxide bleaching is performed under the conditions of 10% pulp density, 70 ° C, 120 minutes, and then washed in the washing step. Obtained. The ISO whiteness of the obtained bleached pulp was 84.5%, and the xylan content was 6.6%.

  The above bleached pulp (concentration: 4.2% by mass) is introduced into one double disc refiner (blade material: 17 chrome, blade width: 4.8 mm, groove width: 4.8 mm) and beaten to 480 ml of CSF did.

(Preparation of base paper)
To the pulp slurry in which the beaten pulp is mixed so that conifer: hardwood = 30: 70 (mass ratio), 0.5% of aluminum sulfate (vs. pulp, solid content conversion), cationized starch (trade name: Oji) Ace K (manufactured by Oji Cornstarch) 0.9% (vs. pulp, solid content conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical) 0.03% (vs. pulp, (Solid content conversion) was sequentially added to the machine chest, and then the recovered white water and the pulp slurry were mixed, and the calcium carbonate (B) was added as a filler before the fan pump so that the paper ash content was 15%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co., Ltd.) was added in front of the screen to prepare a paper stock (concentration: 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.04, and an operation speed of 1500 m / min. After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 2.5 g / m ² , then dry it with a two-stage arrangement dryer, pass it through a machine calendar that becomes on-machine specification, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Preparation of pigment coating solution for undercoat coating layer)
Starch (trade name: Oji Ace A, manufactured by Oji Cornstarch Co., Ltd.) 4 as an adhesive to 100 parts of pigment in a pigment slurry made of heavy calcium carbonate (trade name: Hydrocurve 60, manufactured by Bihoku Flour & Chemical Co., Ltd.) 4 Part, 5 parts of styrene-butadiene copolymer latex (trade name: OJ-2000, manufactured by JSR) were added, and an antifoaming agent and a dye were sequentially added as auxiliary agents, and finally a solid content concentration of 67% was obtained. A pigment coating solution for an undercoat coating layer was prepared.

(Preparation of pigment coating solution for top coat layer)
Kaolin (trade name: Hydra Gloss 90, manufactured by Huber) is added to an aqueous solution in which 0.1 part of polyacrylic acid sodium (trade name: Aron T-50, manufactured by Toagosei Co., Ltd.) is added as a dispersant. 50 parts of heavy calcium carbonate (trade name: Hydrocurve 90, manufactured by Bihoku Powder Chemical Co., Ltd.) (50 parts) was added and dispersed with a Coreless disperser to prepare a pigment slurry. To 100 parts of the pigment slurry, 3 parts of oxidized starch (trade name: Oji Ace A, manufactured by Oji Cornstarch Co.), styrene-butadiene copolymer latex (trade name: OJ-2000, manufactured by JSR) 8 .4 parts, and further, an antifoaming agent and a dye were sequentially added as auxiliaries to finally prepare a pigment coating solution for a top coating layer having a solid content concentration of 66.5%.

(Manufacture of coated paper for printing)
Using a blade coater that supplies the above-mentioned pigment coating liquid for the undercoat coating layer to the base paper for coating (basis weight 47.4 g / m ² ) by the jet fountain method, Coating and drying were carried out so that the dry coating amount was 7.5 g / m ² to obtain a double-sided undercoat coated paper. Subsequently, using a blade coater that supplies the pigment coating liquid for the top coat layer to the double-sided undercoating paper and the coating liquid by the jet fountain method, the dry coating amount per side is 9.5 g. The coated paper was obtained by coating and drying so as to be / m ² . The coated paper obtained in this manner is adjusted to the temperature, linear pressure, and paper feeding conditions with a multi-nip calender in which a metal roll and a resin roll are inclined, and the blank paper glossiness becomes 70%. Thus, a coated paper for printing having a basis weight of 81.4 g / m ² was obtained.

<Example 2>
(Production of hardwood pulp)
As a beating treatment condition, a pulp concentration of 4.3% and a double disk refiner connected in parallel with three machines (blade material: SUS, blade width: 1.0 mm, groove width: 2.0 mm for one machine and blade A hardwood beaten pulp was obtained in the same manner as in Example 1 except that the material was 17 chrome, the blade width was 2.4 mm, and the groove width was 2.4 mm.

(Production of softwood pulp)
In Example 1, softwood bleached pulp (concentration 4.4% by mass) was introduced into one double disc refiner (blade material: 17 chrome, blade width: 4.8 mm, groove width: 4.8 mm). Coniferous beating pulp was obtained in the same manner as in Example 1 except that CSF was beaten to 480 ml.

(Preparation of base paper)
To the pulp slurry in which the beaten pulp was mixed so that conifer: broadleaf = 10: 90 (mass ratio), 0.5% of aluminum sulfate (vs. pulp, solid content), cationized starch (trade name: Oji) Ace K (manufactured by Oji Cornstarch) 0.9% (vs. pulp, solid content conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical) 0.03% (vs. pulp, (Solid content conversion) was sequentially added to the machine chest, and then the recovered white water and the pulp slurry were mixed, and the calcium carbonate (B) was added as a filler before the fan pump so that the paper ash content was 15%. Further, the same procedure as in Example 1 was conducted except that 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co., Ltd.) was added in front of the screen to prepare a paper stock (concentration: 1.01%). Thus, a base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
In the same manner as in Example 1 on the coating base paper (basis weight 47.4 g / m ² ) obtained above, a printing coating having a basis weight of 81.4 g / m ² so that the glossiness of the white paper is 70%. Obtained paper.

<Example 3>
(Production of hardwood pulp)
As a beating condition, the pulp concentration was 4.4%, and a double disc refiner (blade material: SUS, blade width: 1.0 mm, groove width: 2.0 mm) A hardwood beaten pulp was obtained in the same manner as in Example 1 except that the material was 17 chrome, the blade width was 2.4 mm, and the groove width was 2.4 mm.

(Production of softwood pulp)
The pulp concentration was set to 4.4% as the beating treatment condition, and it was introduced into one double disc refiner (blade material: 17 chrome, blade width: 4.8 mm, groove width: 4.8 mm), and beaten to 480 ml of CSF. Except that, softwood beating pulp was obtained in the same manner as in Example 1.

(Preparation of base paper)
To the pulp slurry in which the beaten pulp is mixed so that conifer: hardwood = 5: 95 (mass ratio), 0.5% of aluminum sulfate (vs. pulp, solid content conversion), cationized starch (trade name: Oji) Ace K (manufactured by Oji Cornstarch) 0.9% (vs. pulp, solid content conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical) 0.03% (vs. pulp, (Solid content conversion) is sequentially added to the machine chest, the recovered white water and the above pulp slurry are mixed, and amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Industries, Ltd.) 0.1% is added. As a filler, the calcium carbonate (B) was added before the fan pump so that the paper ash content was 15%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co., Ltd.) was added in front of the screen to prepare a paper stock (concentration: 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.04, and an operation speed of 1500 m / min. After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Example 4>
(Production of hardwood pulp)
Introduced into a double disk refiner (blade material: SUS, blade width: 1.0 mm, groove width: 2.0 mm, 3 machines) with a pulp concentration of 4.6% as the beating treatment condition and connected in parallel with 3 machines Then, a hardwood beaten pulp was obtained in the same manner as in Example 1 except that the beef was beaten up to 350 ml of CSF.

(Preparation of base paper)
To the slurry consisting only of the above-mentioned hardwood pulp, cationized starch (trade name: Oji Ace K, manufactured by Oji Corn Starch) 0.9% (vs. pulp, solid content conversion), AKD sizing agent (trade name: size) Pine K-902 (Arakawa Chemical Co., Ltd.) 0.03% (vs. pulp, solid content conversion) was sequentially added to the machine chest, 0.5% aluminum sulfate was added to the collected white water, and then mixed with the pulp slurry. The calcium carbonate (B) was added as a filler before the fan pump so that the paper ash content was 15%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co., Ltd.) was added in front of the screen to prepare a paper stock (concentration: 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.03, and an operating papermaking speed of 1500 m / min, and after squeezing with two continuous shoe presses, a roll press After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Example 5>
(Production of hardwood pulp)
Double disk refiner (pullet material: 17 chrome, blade width: 2.4 mm, groove width) with pulp concentration of 4.1% as the beating condition and connected in parallel with three machines (the blades are the same) : 2.4 mm), and hardwood beaten pulp was obtained in the same manner as in Example 1 except that it was beaten to 350 ml of CSF.

(Production of softwood pulp)
The pulp concentration was set to 4.4% as the beating treatment condition, and it was introduced into one double disc refiner (blade material: 17 chrome, blade width: 4.8 mm, groove width: 4.8 mm), and beaten to 480 ml of CSF. Except that, softwood beating pulp was obtained in the same manner as in Example 1.

(Preparation of base paper)
Cationized starch (trade name: Oji Ace K, manufactured by Oji Cornstarch) 0.9% (compared to pulp slurry obtained by mixing the hardwood pulp and the softwood pulp with a ratio of softwood: hardwood = 10: 90 (mass ratio) Pulp, solid content conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical Co., Ltd.) as an internal sizing agent, 0.03% (vs. pulp, solid content conversion) was sequentially added to the machine chest. 0.5% of aluminum sulfate is added to the recovered white water, and then mixed with the above pulp slurry. Amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Industries) 0.1% (vs. pulp, solid content conversion) Next, calcium carbonate (A) was added as a filler before the fan pump so that the paper ash content was 18%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co.) is placed in front of the screen, and 0.01% of an anionic acrylic resin (trade name: FA-230, manufactured by Hymo Co.) is applied after the screen. Addition to prepare a stock (concentration 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.03, and an operating papermaking speed of 1500 m / min, and after squeezing with two continuous shoe presses, a roll press After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Example 6>
(Production of hardwood pulp)
Double disk refiner with 3 hardwood bleached pulps (concentration 4.4% by mass) connected in parallel (blade material: SUS, blade width: 1.0 mm, groove width: 2.0 mm, 2 machines and blade material) : 17 chrome, blade width: 2.4 mm, groove width: 2.4 mm was used in combination with one machine), and hardwood beaten pulp was obtained in the same manner as in Example 1 except that it was beaten to CSF 350 ml.

(Production of softwood pulp)
The pulp concentration was set to 4.4% as the beating treatment condition, and it was introduced into one double disc refiner (blade material: 17 chrome, blade width: 4.8 mm, groove width: 4.8 mm), and beaten to 480 ml of CSF. Except that, softwood beating pulp was obtained in the same manner as in Example 1.

(Preparation of base paper)
Cationized starch (trade name: Oji Ace K, manufactured by Oji Cornstarch) 0.9% (compared to pulp slurry obtained by mixing the hardwood pulp and the softwood pulp with a ratio of softwood: hardwood = 10: 90 (mass ratio) Pulp, solid content conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical Co., Ltd.) as an internal sizing agent, 0.03% (vs. pulp, solid content conversion) was sequentially added to the machine chest. 0.5% of aluminum sulfate is added to the recovered white water, and then mixed with the above pulp slurry. Amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Industries) 0.1% (vs. pulp, solid content conversion) Next, calcium carbonate (A) as a filler was added before the fan pump so that the paper ash content was 17% and the hydrated silicate (A) was 2% paper ash content. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co.) is placed in front of the screen, and 0.01% of an anionic acrylic resin (trade name: FA-230, manufactured by Hymo Co.) is applied after the screen. Addition to prepare a stock (concentration 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.03, and an operating papermaking speed of 1500 m / min, and after squeezing with two continuous shoe presses, a roll press After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Example 7>

(Production of hardwood pulp)
Double disk refiner (pullet material: SUS, blade width: 1.0 mm, groove width) with a pulp concentration of 4.4% as the beating treatment condition and connected in parallel with three machines (the blades are the same) 2.0 mm), and hardwood beaten pulp was obtained in the same manner as in Example 1 except that the beef was beaten to 350 ml of CSF.

(Preparation of waste paper pulp)
The concentration of the DIP is 4.4% as a beating process condition, introduced into one double disc refiner (blade material: 17 chrome, blade width: 2.3 mm, groove width: 2.3 mm), up to 270 ml CSF Beating to obtain DIP beaten pulp.

(Preparation of base paper)
Cationized starch (trade name: Oji Ace K, manufactured by Oji Corn Starch) 0.9% (compared to pulp slurry obtained by mixing the hardwood pulp and waste paper pulp with hardwood: used paper = 90: 10 (mass ratio) Pulp, solid content conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical Co., Ltd.) as an internal sizing agent, 0.03% (vs. pulp, solid content conversion) was sequentially added to the machine chest. 0.5% of aluminum sulfate is added to the recovered white water, and then mixed with the above pulp slurry. Amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Industries) 0.25% (vs. pulp, solid content conversion) Next, calcium carbonate (A) was added as a filler before the fan pump so that the paper ash content was 18%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co.) is placed in front of the screen, and 0.012% of an anionic acrylic resin (trade name: FA-230, manufactured by Hymo Co.) is applied after the screen. Addition to prepare a stock (concentration 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.03, and an operating papermaking speed of 1500 m / min, and after squeezing with two continuous shoe presses, a roll press After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Example 8>
(Production of hardwood pulp)
Double disk refiner (pullet material: SUS, blade width: 1.0 mm, groove width) with a pulp concentration of 4.6% as a beating process and connected in parallel with three machines (the blades are the same) 2.0 mm), and hardwood beaten pulp was obtained in the same manner as in Example 4 except that the beef was beaten to 350 ml of CSF.

(Preparation of base paper)
To the slurry consisting only of the above-mentioned hardwood pulp, cationized starch (trade name: Oji Ace K, manufactured by Oji Corn Starch) 0.9% (vs. pulp, solid content conversion), AKD sizing agent (trade name: size) Pine K-902 (Arakawa Chemical Co., Ltd.) 0.03% (vs. pulp, solid content conversion) was sequentially added to the machine chest, 0.5% aluminum sulfate was added to the collected white water, and then mixed with the pulp slurry. , Amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Industries Co., Ltd.) 0.1% (vs. pulp, solid content conversion) was added, and then the calcium carbonate (B) as a filler had a paper ash content of 15% It was added before the fan pump. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co., Ltd.) was added in front of the screen to prepare a paper stock (concentration: 1.01%). The paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.05, and an operating papermaking speed of 1500 m / min. After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Example 9>
(Production of hardwood pulp)
Double disk refiner (pullet material: 17 chrome, blade width: 2.4 mm, groove width) with a pulp concentration of 4.4% as a beating process and connected in parallel with three machines (the blades are the same) : 2.4 mm), and broad-leaved tree beating pulp was obtained in the same manner as in Example 1 except that beating to 270 ml of CSF was performed.

(Preparation of base paper)
To the slurry consisting only of the above-mentioned hardwood pulp, cationized starch (trade name: Oji Ace K, manufactured by Oji Corn Starch) 0.9% (vs. pulp, solid content conversion), AKD sizing agent (trade name: size) Pine K-902 (Arakawa Chemical Co., Ltd.) 0.03% (vs. pulp, solid content conversion) was sequentially added to the machine chest, 0.5% aluminum sulfate was added to the collected white water, and then mixed with the pulp slurry. The calcium carbonate (B) was added as a filler before the fan pump so that the paper ash content was 15%. Further, 0.008% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co., Ltd.) was added in front of the screen to prepare a paper stock (concentration: 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.04, and an operation speed of 1500 m / min. After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

< Reference Example 1 >
(Production of hardwood pulp)
Double disk refiner (pullet material: SUS, blade width: 1.0 mm, groove width) with a pulp concentration of 4.6% as a beating process and connected in parallel with three machines (the blades are the same) 2.0 mm) and beaten to CSF 350 ml.

(Preparation of base paper)
To the slurry consisting only of the above hardwood pulp, cationized starch (trade name: Oji Ace K, manufactured by Oji Corn Starch) 1.2% (vs. pulp, solid content conversion), AKD sizing agent (trade name: size) Pine K-902 (Arakawa Chemical Co., Ltd.) 0.03% (vs. pulp, solid content conversion) was sequentially added to the machine chest, 0.5% aluminum sulfate was added to the collected white water, and then mixed with the pulp slurry. , Amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Co., Ltd.) 0.2% (vs. pulp, solid content conversion) is added, and then the calcium carbonate (B) is used as a filler with a paper ash content of 15%. It was added before the fan pump. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co.) is before the screen, and 0.015% of an anionic acrylic resin (trade name: FA-230, manufactured by Hymo Co.) is after the screen. Addition to prepare a stock (concentration 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.04, and an operation speed of 1500 m / min. After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Example 10 >
(Production of hardwood pulp)
Double disk refiner (pullet material: SUS, blade width: 1.0 mm, groove width) with a pulp concentration of 4.6% as a beating process and connected in parallel with three machines (the blades are the same) 2.0 mm), and hardwood beaten pulp was obtained in the same manner as in Example 4 except that the beef was beaten to 350 ml of CSF.

(Preparation of base paper)
To the slurry consisting only of the above-mentioned hardwood pulp, cationized starch (trade name: Oji Ace K, manufactured by Oji Corn Starch) 0.9% (vs. pulp, solid content conversion), AKD sizing agent (trade name: size) Pine K-902 (Arakawa Chemical Co., Ltd.) 0.03% (vs. pulp, solid content conversion) was sequentially added to the machine chest, 0.5% aluminum sulfate was added to the collected white water, and then mixed with the pulp slurry. , Amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Industries, Ltd.) 0.1% (vs. pulp, solid content conversion) was added, and then the hydrated silicate (B) was added as a paper ash content as a filler. Was added before the fan pump so as to be 7%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co., Ltd.) was added in front of the screen to prepare a paper stock (concentration: 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.05, and an operation speed of 1500 m / min, and is squeezed with two continuous shoe presses, followed by a roll press. After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Example 11 >
(Production of hardwood pulp)
Double disk refiner (pullet material: SUS, blade width: 1.0 mm, groove width) with a pulp concentration of 4.6% as a beating process and connected in parallel with three machines (the blades are the same) 2.0 mm), and hardwood beaten pulp was obtained in the same manner as in Example 4 except that the beef was beaten to 350 ml of CSF.

(Preparation of base paper)
0.5% aluminum sulfate (vs. pulp, solids conversion), cationized starch (trade name: Oji Ace K, manufactured by Oji Cornstarch) 0.9% (vs. pulp, solids) Conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical Co., Ltd.) as an internal sizing agent, 0.03% (vs. pulp, solid content conversion) was sequentially added to the machine chest, and the recovered white water Mixed with the above-mentioned pulp slurry, amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Industries) 0.1% (vs. pulp, solid content conversion) is added, and then the calcium carbonate (B) as a filler Was added before the fan pump so that the paper ash content was 0.5%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co., Ltd.) was added in front of the screen to prepare a paper stock (concentration: 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.04, and an operation speed of 1500 m / min. After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Example 12 >
(Production of hardwood pulp)
Double disk refiner (pullet material: SUS, blade width: 1.0 mm, groove width) with a pulp concentration of 4.6% as a beating process and connected in parallel with three machines (the blades are the same) 2.0 mm), and hardwood beaten pulp was obtained in the same manner as in Example 1 except that the beef was beaten to 350 ml of CSF.

(Preparation of base paper)
0.5% aluminum sulfate (vs. pulp, solid content conversion), cationized starch (trade name: Oji Ace K, manufactured by Oji Cornstarch) 1.5% (vs. pulp, solid content) Conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical Co., Ltd.) as an internal sizing agent, 0.03% (vs. pulp, solid content conversion) was sequentially added to the machine chest, and the recovered white water Mixed with the above pulp slurry, amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Co., Ltd.) 0.3% (vs. pulp, solid content conversion) was added, and then the calcium carbonate (B) as a filler Was added before the fan pump so that the paper ash content was 32%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co.) is placed in front of the screen, and 0.01% of an anionic acrylic resin (trade name: FA-230, manufactured by Hymo Co.) is applied after the screen. Addition to prepare a stock (concentration 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.06, and an operation speed of 1500 m / min, and after squeezing with two continuous shoe presses, a roll press After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Example 13 >
(Production of hardwood pulp)
As a beating process condition, a double disk refiner (pullet material: SUS, blade width: 1.0 mm, groove width: 2.0 mm) with two machines (pulp concentration: 4.4 mass%) connected in parallel with two machines Blade material: 17 chrome, blade width: 2.4 mm, groove width: 2.4 mm was introduced into one machine), and hardwood beaten pulp was obtained in the same manner as in Example 1 except that beaten up to CSF 450 ml .

(Production of softwood pulp)
Softwood bleached pulp (concentration 4.4% by mass) was introduced into one double disc refiner (blade material: 17 chrome, blade width: 4.8 mm, groove width: 4.8 mm) and beaten to 480 ml CSF A conifer beating pulp was obtained in the same manner as in Example 1 except that.

(Preparation of base paper)
The pulp slurry obtained by mixing the hardwood pulp and the softwood pulp so that the ratio of softwood: hardwood = 10: 90 (mass ratio) is mixed with 0.5% aluminum sulfate (vs. pulp, solid content conversion), cationized starch (product) Name: Oji Ace K, manufactured by Oji Cornstarch) 0.9% (vs. pulp, solid content conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical) 0.03% After adding the pulp and solid content in order to the machine chest, the recovered white water and the pulp slurry were mixed, and amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Industries) 0.1% Pulp, solid content conversion) was added, and then the calcium carbonate (B) was added as a filler before the fan pump so that the paper ash content was 10%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co., Ltd.) was added in front of the screen to prepare a paper stock (concentration: 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.08, and an operation speed of 1500 m / min. After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Example 14 >
(Production of hardwood pulp)
As a beating treatment condition, a double disk refiner (pullet material: SUS, blade width: 1.0 mm, groove width: 2.0 mm) and a single machine with a pulp (concentration 4.3 mass%) connected in parallel in three machines Blade material: 17 chrome, blade width: 2.4 mm, groove width: 2.4 mm was used in combination of two machines), and hardwood beaten pulp was obtained in the same manner as in Example 1 except that beaten up to CSF 450 ml .

(Production of softwood pulp)
Softwood bleached pulp (concentration 4.4% by mass) was introduced into one double disc refiner (blade material: 17 chrome, blade width: 4.8 mm, groove width: 4.8 mm) and beaten to 480 ml CSF A conifer beating pulp was obtained in the same manner as in Example 1 except that.

(Production of size press liquid)
Starch (trade name: Oji Ace A, manufactured by Oji Corn Starch Co., Ltd.) 35 as an adhesive to 100 parts of pigment in a pigment slurry made of heavy calcium carbonate (trade name: Hydrocurve 60, manufactured by Bihoku Powder Chemical Co., Ltd.) Part, 5 parts of styrene-butadiene copolymer latex (trade name: OJ-2000, manufactured by JSR Co., Ltd.) are added, and an antifoaming agent and a dye are sequentially added as auxiliary agents, and finally a solid content concentration of 28% is obtained. A size press solution was prepared.

(Preparation of base paper)
To the pulp slurry in which the beaten pulp was mixed so that conifer: broadleaf = 10: 90 (mass ratio), 0.5% of aluminum sulfate (vs. pulp, solid content), cationized starch (trade name: Oji) Ace K (manufactured by Oji Cornstarch) 0.9% (vs. pulp, solid content conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical) 0.03% (vs. pulp, (Solid content conversion) is sequentially added to the machine chest, and then the recovered white water and the above-described pulp slurry are mixed, and amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Industries) 0.1% (vs. pulp, solid) Then, the calcium carbonate (B) was added as a filler before the fan pump so that the paper ash content was 15%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co., Ltd.) was added in front of the screen to prepare a paper stock (concentration: 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.04, and an operation speed of 1500 m / min. After squeezing with water, smoothing treatment, and drying with a single-stage drier, using the above-mentioned size press liquid using a rod metalling type size press apparatus, the solid content becomes 6.0 g / m ^2. Perform size press treatment, then dry with a two-stage dryer, and pass through a machine calender with on-machine specifications for coating with a moisture content of 4.5% and a basis weight of 55.4 g / m ² I got the base paper.

(Preparation of pigment coating solution for top coat layer)
Kaolin (trade name: Hydra Gloss 90, manufactured by Huber) is added to an aqueous solution in which 0.1 part of polyacrylic acid sodium (trade name: Aron T-50, manufactured by Toagosei Co., Ltd.) is added as a dispersant. 50 parts of heavy calcium carbonate (trade name: Hydrocurve 90, manufactured by Bihoku Powder Chemical Co., Ltd.) (50 parts) was added and dispersed with a Coreless disperser to prepare a pigment slurry. To 100 parts of the pigment slurry, 3 parts of oxidized starch (trade name: Oji Ace A, manufactured by Oji Cornstarch Co.), styrene-butadiene copolymer latex (trade name: OJ-2000, manufactured by JSR) 8 .4 parts, and further, an antifoaming agent and a dye were sequentially added as auxiliaries to finally prepare a pigment coating solution for a top coating layer having a solid content concentration of 66.5%.

(Manufacture of coated paper for printing)
Using a blade coater that supplies the above-mentioned pigment coating liquid for the topcoat coating layer to the base paper for coating (basis weight 55.4 g / m ² ) by the jet fountain method, Coating and drying were performed so that the dry coating amount was 13 g / m ² to obtain a double-sided undercoat coated paper. The coated paper obtained in this manner is adjusted to the temperature, linear pressure, and paper feeding conditions with a multi-nip calender in which a metal roll and a resin roll are inclined, and the blank paper glossiness becomes 70%. Thus, a coated paper for printing having a basis weight of 81.4 g / m ² was obtained.

<Comparative Example 1>
(Production of hardwood pulp)
Double disk refiner (blade material: Ni-Hard, blade width: 4.0 mm, groove) with a pulp concentration of 4.2% as the beating process and connected in parallel with three machines (the blades are the same) Width: 4.0 mm) and hardwood beaten pulp was obtained in the same manner as in Example 1 except that it was beaten to CSF 450 ml.

(Preparation of base paper)
0.5% aluminum sulfate (vs. pulp, solids conversion), cationized starch (trade name: Oji Ace K, manufactured by Oji Cornstarch) 0.9% (vs. pulp, solids) Conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical Co., Ltd.) as an internal sizing agent, 0.03% (vs. pulp, solid content conversion) was sequentially added to the machine chest, and the recovered white water It mixed with the said pulp slurry, and the said calcium carbonate (B) was added before the fan pump so that paper ash content might be 15% as a filler. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co., Ltd.) was added in front of the screen to prepare a paper stock (concentration: 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.04, and an operation speed of 1500 m / min. After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Comparative example 2>
(Production of hardwood pulp)
Double disk refiner (pullet material: SUS, blade width: 1.0 mm, groove width) with a pulp concentration of 4.6% as a beating process and connected in parallel with three machines (the blades are the same) 2.0 mm), and hardwood beaten pulp was obtained in the same manner as in Example 1 except that beating to 450 ml of CSF was performed.

(Production of softwood pulp)
The pulp concentration was 4.5% as the beating treatment condition, and it was introduced into one double disc refiner (blade material: 17 chrome, blade width: 2.3 mm, groove width: 2.3 mm) and beaten to 480 ml of CSF. Except that, softwood beating pulp was obtained in the same manner as in Example 1.

(Preparation of base paper)
To the pulp slurry in which the beaten pulp is mixed so that conifer: hardwood = 30: 70 (mass ratio), 0.5% of aluminum sulfate (vs. pulp, solid content conversion), cationized starch (trade name: Oji) Ace K (manufactured by Oji Cornstarch) 0.9% (vs. pulp, solid content conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical) 0.03% (vs. pulp, (Solid content conversion) is sequentially added to the machine chest, and the recovered white water and the pulp slurry are mixed, and then amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Industries, Ltd.) 0.3% is added. As a filler, the calcium carbonate (B) was added before the fan pump so that the paper ash content was 15%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo) and 0.01% of an anionic acrylic resin (trade name: FA-230, manufactured by Hymo) are sequentially added in front of the screen. A paper stock was prepared (concentration 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.06, and an operation speed of 1500 m / min, and after squeezing with two continuous shoe presses, a roll press Squeezed with water, smoothed, dried with a single row dryer, and then oxidized with a rod metalling type size press (4.0% by mass) (Oji Ace A, manufactured by Oji Cornstarch Co., Ltd.) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Comparative Example 3>
(Production of hardwood pulp)
As a beating treatment condition, the pulp concentration was 4.2%, and a double disk refiner (blade material: SUS, blade width: 1.0 mm, groove width: 2.0 mm was used for one machine A hardwood beaten pulp was obtained in the same manner as in Example 1 except that the material was 17 chrome, the blade width was 2.4 mm, and the groove width was 2.4 mm.

(Preparation of base paper)
0.5% aluminum sulfate (vs. pulp, solids conversion), cationized starch (trade name: Oji Ace K, manufactured by Oji Cornstarch) 0.9% (vs. pulp, solids) Conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical Co., Ltd.) as an internal sizing agent, 0.03% (vs. pulp, solid content conversion) was sequentially added to the machine chest, and the recovered white water Mixed with the above-mentioned pulp slurry, amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Industries) 0.1% (vs. pulp, solid content conversion) is added, and then the calcium carbonate (B) as a filler Was added before the fan pump so that the paper ash content was 15%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co., Ltd.) was added in front of the screen to prepare a paper stock (concentration: 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.04, and an operation speed of 1500 m / min. After squeezing with water, smoothing, drying with a single-stage dryer, using a rod metalling type size press device, oxidized starch with a concentration of 4.0% by mass (trade name: Oji Ace A, manufactured by Oji Cornstarch) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Comparative Example 4>
(Production of hardwood pulp)
Double disk refiner (pullet material: SUS, blade width: 1.0 mm, groove width) with a pulp concentration of 4.4% as the beating treatment condition and connected in parallel with three machines (the blades are the same) 2.0 mm), and hardwood beaten pulp was obtained in the same manner as in Example 1 except that beating to 450 ml of CSF was performed.

(Production of softwood pulp)
The pulp concentration was set to 4.4% as the beating treatment condition, and it was introduced into one double disc refiner (blade material: 17 chrome, blade width: 4.8 mm, groove width: 4.8 mm), and beaten to 480 ml of CSF. Except that, softwood beating pulp was obtained in the same manner as in Example 1.

(Preparation of base paper)
To the pulp slurry in which the beaten pulp is mixed so that conifer: hardwood = 30: 70 (mass ratio), 0.5% of aluminum sulfate (vs. pulp, solid content conversion), cationized starch (trade name: Oji) Ace K (manufactured by Oji Cornstarch) 0.9% (vs. pulp, solid content conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical) 0.03% (vs. pulp, (Solid content conversion) is sequentially added to the machine chest, and then the recovered white water and the pulp slurry are mixed, and then amphoteric polyacrylamide (trade name: Polystron 1280, manufactured by Arakawa Chemical Industries, Ltd.) 0.1% is added. As a filler, the calcium carbonate (B) was added before the fan pump so that the paper ash content was 15%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo) and 0.01% of an anionic acrylic resin (trade name: FA-230, manufactured by Hymo) are sequentially added in front of the screen. A paper stock was prepared (concentration 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.995, a Vr / Vw ratio of 1.06, and an operation speed of 1500 m / min, and after squeezing with two continuous shoe presses, a roll press Squeezed with water, smoothed, dried with a single row dryer, and then oxidized with a rod metalling type size press (4.0% by mass) (Oji Ace A, manufactured by Oji Cornstarch Co., Ltd.) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

<Comparative Example 5>
(Production of hardwood pulp)
Double disk refiner (pullet material: SUS, blade width: 1.0 mm, groove width) with a pulp concentration of 4.4% as the beating treatment condition and connected in parallel with three machines (the blades are the same) 2.0 mm), and hardwood beaten pulp was obtained in the same manner as in Example 1 except that the beef was beaten to 400 ml of CSF.

(Production of softwood pulp)
The pulp concentration was set to 4.4% as the beating treatment condition, and it was introduced into one double disc refiner (blade material: 17 chrome, blade width: 4.8 mm, groove width: 4.8 mm), and beaten to 480 ml of CSF. Except that, softwood beating pulp was obtained in the same manner as in Example 1.

(Preparation of base paper)
To the pulp slurry in which the beaten pulp is mixed so that conifer: hardwood = 30: 70 (mass ratio), 0.5% of aluminum sulfate (vs. pulp, solid content conversion), cationized starch (trade name: Oji) Ace K (manufactured by Oji Cornstarch) 0.9% (vs. pulp, solid content conversion), AKD sizing agent (trade name: Size Pine K-902, manufactured by Arakawa Chemical) 0.03% (vs. pulp, (Solid content conversion) was sequentially added to the machine chest, and the recovered white water and the pulp slurry were mixed, and the calcium carbonate (B) was added as a filler before the fan pump so that the paper ash content was 15%. Furthermore, 0.016% of a cationic acrylic resin (trade name: DR-3015, manufactured by Hymo Co., Ltd.) was added in front of the screen to prepare a paper stock (concentration: 1.01%). This paper stock is formed with a gap former at a J / W ratio of 0.989, a Vr / Vw ratio of 1.07, and an operating papermaking speed of 1500 m / min. After squeezing with two continuous shoe presses, a roll press Squeezed with water, smoothed, dried with a single row dryer, and then oxidized with a rod metalling type size press (4.0% by mass) (Oji Ace A, manufactured by Oji Cornstarch Co., Ltd.) Using an aqueous solution, perform a size press treatment so that the solid content is 1.6 g / m ² , then dry with a two-stage array dryer, and pass through a machine calendar that becomes on-machine specifications, A base paper for coating having a water content of 4.5% and a basis weight of 47.4 g / m ² was obtained.

(Manufacture of coated paper for printing)
A basis weight of 81.4 g / m ² was obtained in the same manner as in Example 1 except that the base paper for coating (basis weight of 47.4 g / m ² ) obtained above was used so that the glossiness of the white paper was 70%. A coated paper for printing was obtained.

(Evaluation of coated paper for printing)
Weight-weighted average fiber length of disaggregated pulp, fiber length distribution coefficient The paper base material was disaggregated by the pulp disaggregation method described in JIS P 8220, and the fiber length of the obtained disaggregated pulp was measured by Fiber Lab manufactured by Kajaani, The weight average fiber length (W) and the number average fiber length (M) were determined. Then, the weight weighted average fiber length (W) and the number average fiber length (M) are substituted into the weight weighted average fiber length (W) / number average fiber length (M) formula to obtain the fiber length distribution coefficient. Calculated.

Tensile Strength Aspect Ratio Calculates the aspect ratio (longitudinal tensile strength / lateral tensile strength) by measuring longitudinal tensile strength and transverse tensile strength according to the method specified in JIS P 8113: 2006. did.

Internal bond strength JAPAN TAPPI Paper pulp test method no. 18-2: The interlayer strength of the coated paper was measured according to the method defined in 2000 (internal bond tester method).

Stiffness The stiffness of the coated paper was measured in accordance with the method specified in JIS P 8143: 1996 “stiffness test method by paper Clark stiffness tester”, and the geometric mean value was obtained (humidity controlled environment: 23 ± 1 ° C. 50 ± 2% RH).

Freeness of raw pulp The raw pulp obtained by beating was measured for freeness in accordance with JIS P8121.

Freeness of disaggregated pulp The paper substrate was disaggregated by the pulp disaggregation method described in JIS P 8220, and the freeness of the disaggregated pulp obtained in this way was measured according to JIS P 8121.

Apparent Specific Gravity of Filler The apparent specific gravity of the filler was measured according to the method defined in JIS K 6220-1: 2001 “Rubber Compounding Agent—Test Method—Part 1: General”.

Absorption coefficient Incident light intensity I ₀ and transmitted light intensity I with respect to filler slurry at various concentrations were measured with a spectrophotometer. The molar extinction coefficient (ε) according to Lambert-Beer's law expressed as log ₁₀ (I ₀ / I) = εcd, where d is the thickness of the absorbing material layer and c is the concentration, was calculated.

Average particle diameter The average particle diameter was measured using a Microtrac particle size distribution analyzer (MT3000) manufactured by Nikkiso Co., Ltd.

Offset rotary printing suitability (off-roll wrinkles)
Using an offset rotary printing press (Mitsubishi Lithopia L-BT3-1100, manufactured by Mitsubishi Heavy Industries, Ltd.), a combination of a four-color solid pattern on both sides, a four-color solid pattern on one side, and a light pattern on the other side in pink In the design, the printing speed was 330 m / min, the paper surface temperature at the outlet of the dryer was 120 ° C., the cooling roll after passing through the dryer was printed with cooling water at 10 ° C., and then continuously folded. After printing, the degree of off-ring wrinkles was visually evaluated according to the following criteria.
(Excellent) 6 → 1 (poor)
6: No off-ring wrinkles occur.
5: A part of wide off-ring wrinkles is generated, but the depth of the wrinkles is relatively shallow, and there is no practical problem at all.
4: Wide off-ring wrinkles are generated throughout, but the depth of the wrinkles is relatively shallow, which is a level that causes no problem in practice.
3: Narrow wrinkles with a narrow width are generated in part, but the depth of the wrinkles is shallow, which is a level that causes no problem in practical use.
2: A large number of wide off-wrinkles are generated throughout, and the wrinkle depth is moderate, which is a practically problematic level.
1: A large number of narrow off-wrinkles are generated on the entire surface, and the wrinkle depth is deep.

(Print quality): Printing glossiness Printing was performed using 0.1 cc of printing ink (Values-G type, manufactured by Dainippon Ink & Chemicals, Inc.) with an RI printer, and the printing glossiness was visually evaluated.
A: Print quality is particularly excellent.
○: Print quality is excellent.
Δ: Print quality is slightly inferior.
X: Print quality is inferior.

Blister resistance suitability The coated paper for printing was immersed in an oil bath at 180 ° C. for 1 minute, and the blister generation state of the coated paper was visually judged according to the following criteria.
(Excellent) 6 → 1 (poor)
6: Blister is not observed at all.
5: Blister is hardly observed and is an excellent level.
4: Although a very small amount of fine blisters are observed, there is no practical problem.
3: Fine blisters are observed in a small amount, but at a level where there is no practical problem.
2: Level at which blisters are clearly observed and have practical problems.
1: A level in which a large amount of blisters are observed and there is a practical problem.

Formation The watermark formation of the base paper was visually evaluated according to the following criteria.
: Very good.
: Good.
: Slightly inferior, but at a level where there is no practical problem.
X: Extremely inferior and not practical.

Comprehensive evaluation Comprehensive evaluation as a coated paper for printing was judged according to the following criteria.
: Very good.
: Good.
: Slightly inferior, but at a level where there is no practical problem
X: Extremely inferior and not practical.

  As is clear from Table 1, the coated paper for printing according to the present invention had extremely excellent performance as a printing paper.

  The coated paper for printing according to the present invention has a very good quality as a printing paper because the formation is good, the paper interlayer strength and rigidity are high, wrinkles and blisters are suppressed during offset rotary printing.

Claims (3)

More than 50% by weight of bleached pulp used in paper stock is made from eucalyptus or acacia wood, pulped by a cooking method in which cooking liquor is added in portions, and manufactured by a multistage bleaching process A process of forming wet paper with a gap former type wire part that is bleached pulp and dehydrates with a forming roll and / or a forming shoe by ejecting a paper material from a head box to two wires forming a loop. In the press part, the wet paper is squeezed with one or more shoe-type wet press devices, in the dryer part, the wet paper is dried with a single-stage drier at least in the initial stage of drying before the surface treatment, and the transfer. Pigment and adhesive on at least one side of the base paper obtained by surface treatment using a mold size press A coated paper for printing, comprising a step of providing at least one pigment coating layer as a component, wherein the base paper has an apparent specific gravity of 0.5 or less measured according to JIS K 6220-1: 2001, and lumbard・ Molar extinction coefficient of 5.0 or more according to Beer's law and average particle size (50% volume integrated particle size measured by laser diffraction particle size distribution meter) 1 to 30% by mass of filler of 1 μm or more, JIS P 8220: 1998, TPPI No. of the disaggregated pulp obtained by disaggregating the coated paper for printing by the pulp disaggregation method. The weight weighted average fiber length measured by the pulp fiber length test method in the optical automatic measurement method defined in 52: 2000 is 0.6 to 2.0 mm, and the fiber length distribution coefficient is 1.5 to 4.0. The freezing degree of the disaggregated pulp measured in accordance with JIS P 8121: 1995 is 250 to 500 ml, and the tensile strength of the coated coated paper measured in accordance with JIS P 8113: 2006 is A coated paper for printing having an aspect ratio of 3.0 or less.   The coated paper for printing according to claim 1, wherein the aspect ratio of the tensile strength of the coated paper for printing is 1.3 to 3.0. The coated paper for printing according to claim 1 or 2, wherein a final nip of the press part is a roll press and a preceding stage is a shoe press.