JP2010236112A - Newsprint paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide newsprint paper that has high opacity in spite of being lightweight, excellent printability and printing opacity and is suitably useful for offset printing, for example, high-speed multicolor offset rotary printing using cold-set ink. <P>SOLUTION: The newsprint paper is formed of a raw material pulp composed of used paper pulp as a main component and a filler at least as constituent components. The filler contains white carbon (A), calcium carbonate (B) and regenerated particles (C). The regenerated particles (C) are inorganic particles obtained from papermaking sludge as a main raw material through a dehydration step, drying step, combustion step and grinding step, has a weight measured based on JIS P 8124 of 36-48 g/m<SP>2</SP>, a white paper opacity measured based on JIS P 8149 of not less than 90%, and a printing opacity of not less than 85%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to newsprint. More specifically, the present invention relates to a newspaper that is lightweight but has high opacity, excellent printability and printing opacity, and can be suitably used for offset printing such as high-speed multi-color offset rotary printing using a cold set type ink. .

In order to reduce the burden of delivery work, reduce delivery costs, and effectively use resources, it is desired to reduce the weight of newspapers used in large quantities every day. In recent years, the basis weight is 36-48 g / m ² . The main use is newspaper.

  However, with the weight reduction of newspapers and the effective use of resources, the used ratio of waste paper exceeds 50%, and the blank paper opacity and printing opacity of newspapers are decreasing. In order to suppress such a decrease in opacity, an inorganic filler is blended, but the surface strength is reduced due to the increase of the inorganic filler, causing troubles such as paper dust.

  In recent years, with the increase in advertising media, there has been an increasing demand for the quality of the printed surface of newspaper. For this reason, newspaper companies are increasing the speed of rotary presses and increasing the number of tower presses for double-sided color printing, and efforts are being made to improve the printing surface quality in multicolor printing with high-speed offset rotary printing. However, under such circumstances, particularly in multi-color printing (addition of a double-sided color tower press) in high-speed offset rotary printing, there is a problem of reduced printability and reduced newspaper opacity.

  The above-mentioned problems cannot be dealt with by the conventional technique of physically flattening the surface of the base paper or the technique of applying a surface treatment agent to the surface of the base paper. This is because, for example, when the surface of a base paper containing a large amount of waste paper pulp is subjected to a flattening treatment, the paper is once made, deinked by physical and chemical means, and deteriorated. As a result, it falls off from the surface of the newsprint, and also facilitates the dropout of the filler contained in the paper, leading to contamination of the printing equipment and poor printing.

  As a technique for solving these problems, Patent Document 1 discloses a specific amount of a water-soluble polymer on the surface of a base paper that includes recycled paper pulp and mechanical pulp is composed of at least a specific amount of pulp and a filler. A newsprint with a coating liquid containing a compound is disclosed. The newsprint is bulky for a high percentage of waste paper pulp, and has improved printing opacity and printability to some extent. However, while the amount of ink used increases due to the use of mower color in high-speed offset color printing, improvement in printing opacity cannot be expected only with the bulkiness, and it is not expected that the increased ink is retained on the surface of the base paper.

On the other hand, as a technique for improving printing suitability and printing opacity in a newspaper offset rotary press, Patent Document 2 discloses calcium carbonate on a base paper containing deinked pulp (spent paper pulp) and calcium carbonate as a filler. There is disclosed a fine coated paper for printing having a basis weight of 48 g / m ² or less, in which a coating layer containing a pigment and an adhesive is provided in a specific range. This finely coated paper for printing is intended to improve printability and printing opacity in a newspaper offset rotary press by using an ink adsorbing pigment in the coating layer. However, since the coating layer contains an inorganic substance, there is a problem that when printing is performed with a newspaper offset rotary press, the paper powder is not easily dropped off, and the printed surface derived from the paper powder is stained.

JP 2009-013513 A JP 2007-270377 A

  The present invention has been made in view of the background art described above, and is lightweight and high in opacity, and has recently become a mainstream, using a cold set type ink, for example, 170 to 200,000 parts / hour An object of the present invention is to provide newsprint paper with improved printability and printing opacity, which are issues to be improved as the amount of used paper is increased and the weight is reduced in multi-color offset rotary printing at high speed.

The present invention
Newspaper paper comprising at least constituents of raw pulp containing filler pulp as a main component and filler,
As filler, it contains white carbon (A), calcium carbonate (B) and regenerated particles (C),
Recycled particles (C) are inorganic particles obtained using papermaking sludge as the main raw material, and through a dehydration step, a drying step, a combustion step, and a pulverization step,
The basis weight measured in accordance with JIS P 8124 is 36 to 48 g / m ² , the blank paper opacity measured in accordance with JIS P 8149 is 90% or more, and the printing opacity is 85% or more. It relates to newspaper.

The newsprint of the present invention has a low basis weight such as 36 to 48 g / m ² and is lightweight, but also has a high ink setting property even in high-speed multicolor offset rotary printing using a cold set type ink. It has good printing operability and ink setting, and is excellent in printability and printing opacity.

Schematic showing a partial configuration example of the production facility flow of regenerated particles It is the partial schematic of a 2nd combustion furnace, (a) is a partially broken schematic sectional drawing of a 2nd combustion furnace, (b) is an internal expansion schematic plan view of a 2nd combustion furnace.

(Embodiment)
The newsprint of the present invention comprises raw pulp containing waste paper pulp as a main component and a filler at least as constituent components.

  The waste paper pulp is manufactured from, for example, tea waste paper, craft envelope waste paper, magazine waste paper, newspaper waste paper, flyer waste paper, office waste paper, corrugated waste paper, recycle paper waste, upper white waste paper, Kent waste paper, imitation waste paper, old paper waste paper, etc. Examples of such pulps include disaggregated waste paper pulp, disaggregated / deinked waste paper pulp, and disaggregated / deinked / bleached waste paper pulp. One or more of these can be appropriately selected and used.

  In the present invention, the amount of waste paper pulp is 50 to 100% by mass of the total amount of raw material pulp, from the viewpoint of environmental protection and the provision of sufficient bulkiness while maintaining white paper opacity of the resulting newspaper. Furthermore, it is preferable that it is 60-90 mass%.

  As a raw material pulp, as long as the object of the present invention is not hindered, for example, stone ground pulp (SGP), pressurized stone ground pulp (PGW), refiner ground pulp (RGP), chemiground pulp, in addition to the waste paper pulp. (CGP), Thermo Grand Pulp (TGP), Grand Pulp (GP), Thermo Mechanical Pulp (TMP), Chemi Thermo Mechanical Pulp (CTMP), Refiner Mechanical Pulp (RMP), etc. Mechanical Pulp; Hardwood Bleached Kraft Pulp (LBKP) , Softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), softwood unbleached kraft pulp (NUKP), hardwood semi-bleached kraft pulp (LSBKP), softwood half-bleached kraft pulp (NSBKP), hardwood sulfite pulp, conifer Sulfurous acid From various pulps such chemical pulp such as pulp, one or more suitably selected, can be used to adjust the ratio.

  The bleaching method for producing chemical pulp is not particularly limited, but ECF pulp bleached without using molecular chlorine such as chlorine gas in the bleaching step, and further chlorine compounds such as chlorine dioxide From the viewpoint of environmental conservation, TCF pulp that has been bleached without using any is preferred.

  In the news paper, from the viewpoint of effective use of resources, in particular, the use of waste paper pulp and higher blending have been demanded in recent years, but the increase in waste paper pulp makes it difficult to ensure the prescribed paper strength, In some cases, printability such as ink setting properties and ink fillability may be deteriorated.

  Among the used paper pulp, the use of deinked pulp obtained by deinking newspaper wastepaper is the most efficient in terms of resource recycling because the constituent materials are approximate. However, especially in waste newspapers, deinked pulp that has been recycled many times exists, and the pulp fiber deteriorates due to repeated regeneration treatment, not only the opacity decreases, but also becomes brittle, paper dust and Problems arise such as powder falling and fibers on the paper surface being taken up by the offset printing bracket.

  However, in the present invention, as will be described in detail below, as fillers internally added to the raw material pulp, three specific types of compounds, white carbon (A), calcium carbonate (B) and regenerated particles (C), are used. The combined use creates a synergistic effect of improving printability while covering the shortcomings of waste paper pulp.

(A) White carbon As one of the fillers, white carbon (A) is, for example, an alkali silicate solution obtained by dispersing mineral-insoluble and acid-soluble particles in an alkali silicate aqueous solution and then adding a mineral acid. Neutralized aqueous solution, further produced by adding at least the same mole of mineral acid as the particles dispersed in the aqueous alkali silicate solution to the precipitated white carbon. It is particularly preferable to use carbon (hereinafter referred to as undried white carbon).

More specifically, for example, an alkali silicate aqueous solution (sodium silicate aqueous solution or silicic acid) in which SiO ₂ / R ′ ₂ O (molar ratio, R ′ represents Na or K) is in the range of 2.0 to 3.4. A mineral acid such as sulfuric acid is added to the aqueous potassium solution to neutralize the alkaline aqueous silicate solution. The mineral acid may be added at once or divided into a plurality of parts. When adding by dividing into a plurality of times, the first addition of the mineral acid is performed in the temperature range of the aqueous alkali silicate solution of 20 to 60 ° C., and the amount of mineral acid necessary for neutralizing the aqueous alkali silicate solution is increased. Add 10-50% by weight. Further, after raising the temperature of the alkali silicate aqueous solution to 85 ° C. or higher and lower than the boiling point of the aqueous solution, an aging time is provided as necessary, and then the second and subsequent mineral acids are added all at once or continuously. After the addition, an aging time may be provided as necessary.

The white carbon produced by the above-described method includes alkali-insoluble and acid-soluble particles, and a mineral acid is further added to dissolve the particles. At this time, it is preferable that the mineral acid is added in an amount of at least the same mole as the alkali-insoluble and acid-soluble particles initially dispersed, and the pH of the slurry containing white carbon is adjusted in the range of 4-6. is there.

  White carbon has small primary particles and a relatively uniform particle size at the stage of completion of the reaction in the production process, but it does not exist in the form of primary particles in the stable period after the reaction. Aggregates to form secondary particles.

Further, when white carbon undergoes a drying process at the stage of commercialization, secondary particles may form agglomerates and further coarse particles may be generated. The reason is not clear, but the dry white carbon in the slurry state does not have some silica atoms and is liberated in the form of -SiOH, and the two-dimensional structure becomes a net tube and the surface is porous. ing. On the other hand, the dried white carbon has a basic structure of SiO ₂ tetrahedron and shares a three-dimensional network structure sharing oxygen.

  Therefore, when the white carbon is dried once, the bonding strength with the cellulose fibers due to -SiOH on the surface is reduced. Therefore, the white carbon after the reaction remains in a slurry state and is wet without being subjected to a drying treatment. After pulverizing and subdividing the excessive secondary agglomerates generated in the stable period, it can be added to the raw material pulp as a filler, for example, high speed papermaking at a speed of 1300 m / min or more is possible. In addition, a newspaper based on the present invention is obtained which is lightweight, free of paper dust and excellent in opacity, particularly in printing opacity, while supporting high-speed rotary offset printing such as 170 to 200,000 copies / hour. It is suitable for.

  The excessive white carbon agglomerates remaining after the wet pulverization are removed, or the volume average particle diameter of white carbon is 3 to 10 μm, preferably 4 to 9 μm, more preferably 5 to 8 μm by laser analysis. In order to easily adjust the ratio of white carbon particles having a particle diameter of 1 to 30 μm to 80% by mass or more, it is preferable to perform a classification treatment after the wet pulverization.

  If the volume average particle size of white carbon by laser analysis is less than 3μm, the loss of dehydration in the paper making process will increase, and it will remain in the white water, causing it to bind to other foreign substances and cause damage and damage to the equipment. There is a fear. Conversely, when the volume average particle diameter of white carbon exceeds 10 μm, it appears that the paper surface is scattered as agglomerates, leading to a decrease in the strength of the paper surface, generation of paper dust, and a decrease in opacity, particularly printing opacity. There is a fear. Accordingly, the white carbon used as a filler in the present invention has a volume average particle diameter of 3 μm or more, more preferably 4 μm or more, particularly preferably 5 μm or more by laser analysis, and is preferably 10 μm or less, more preferably 9 μm or less, particularly 8 μm. The following is possible, for example, high-speed paper-making such as a paper-making speed of 1300 m / min or more, and is lightweight and generates paper dust while supporting high-speed rotary printing such as 170 to 200,000 copies / hour, for example. Therefore, it is preferable for obtaining newsprint paper having excellent opacity, particularly printing opacity.

Further, the ratio of white carbon particles having a particle size of 1 to 30 μm by laser analysis is preferably 80% by mass or more, more preferably 82% by mass or more, that is, by sharpening the particle size, It is possible to increase the dispersibility of white carbon and to form a homogeneous paper layer. Thereby, the strength of the paper surface can be improved, the generation of paper dust can be suppressed, and at the same time, the opacity, particularly the printing opacity can be improved. Although it is preferable to make the ratio of white carbon particles having a particle diameter of 1 to 30 μm as close as possible to 100% by mass as much as possible, in industrial production of white carbon that is an aggregate of fine primary particles. , 100% by mass is difficult, from the point of production cost,
The proportion of white carbon particles having a particle diameter of 1 to 30 μm is at most about 95% by mass.

  In this specification, the laser analysis method refers to a particle size distribution measuring device (laser method) for a dispersion solution in which 10 mg of a sample is added to 8 mL of a methanol solution and dispersed for 3 minutes by an ultrasonic disperser (output: 80 W). The analysis method using a Microtrac particle size analyzer (manufactured by Nikkiso Co., Ltd.).

  In the present invention, for example, it is preferable to make papermaking by previously diluting the dry white carbon obtained as described above to a concentration of 8% by mass or less, and internally adding the diluted solution to the raw material pulp.

  Undried white carbon has a characteristic (thixotropic property) in which the apparent viscosity decreases at a high shear rate. When a shearing force is applied to secondary aggregates and aggregates of white carbon, aggregation is broken, and one after another. It becomes a small aggregate. In order to obtain small agglomerates by this shearing force and not to cause problems due to secondary agglomerates and agglomerates of white carbon, the white carbon is preferably 8 mass% or less in advance, more preferably 3%. It is desirable to add to the raw material pulp after diluting and dispersing to a concentration of ˜7.5 mass%, particularly preferably 3 to 6 mass%. The concentration of white carbon is 8% by mass or less from the viewpoint of effectively imparting the dispersing capacity of the existing equipment, the shearing force to the secondary aggregates, and not making the particle size distribution of the dispersed white carbon broad. For example, it is preferable to dilute in advance in high-speed papermaking such as a papermaking speed of 1300 m / min or more.

  Furthermore, in order to prevent such agglomeration of small agglomerated particles, it is preferable to add the diluted solution of undried white carbon to the raw pulp before the screen.

(B) Calcium carbonate Calcium carbonate (B), which is one of the fillers, is preferably light calcium carbonate. Examples of the shape of the light calcium carbonate include a needle shape, a columnar shape, a spherical shape, a spindle shape, a cubic shape and the like, and any of them can be used in the present invention. Calcium carbonate and spindle-shaped light calcium carbonate are preferable, and light chestnut-shaped light calcium carbonate having crystal protrusions in a three-dimensional direction (hereinafter referred to as calcium chloride calcium carbonate) is particularly preferable.

The reason why calcite-based light calcium carbonate is suitable is not clear, but calcite-based light calcium carbonate has better dispersibility in the paper layer than aragonite-based calcium carbonate or vaterite-based calcium carbonate. Uniform dispersibility with (A) and regenerated particles (C) to be described later, in particular, obtained by combustion treatment at a temperature of 300 ° C. or higher and lower than 500 ° C. in the unburned white carbon or in the first combustion step described later Excellent uniform dispersibility with regenerated particles, and less quality bias due to filler used. Therefore, even when the basis weight is as low as 36 to 48 g / m ² as in the newsprint of the present invention, the offset rotary printing operability is good at the time of high-speed multicolor rotary printing using a cold set type ink. Therefore, while having high ink fillability, the ink setting property is also good, the printing opacity is improved, and the printability is excellent.

  In the process of obtaining calcium carbonate having a stable calcite-type crystal structure such as a spindle shape or a columnar shape, or a calcium carbonate having a metastable aragonite-type crystal structure by reacting a calcium dioxide-containing gas with calcium hydroxide. When the carbon dioxide-containing gas supply method is adjusted, or when dehydration, drying, and heat treatment are performed, for example, an additive such as condensed phosphoric acid or a metal salt thereof is added to agglomerate a spindle-like or columnar crystal structure. Obtained by crystallization.

In the case of calcite-based calcium carbonate, calcite is produced more naturally than limestone because it is more stable than other crystal structures. In addition, artificially, for example, natural limestone is decomposed into calcium oxide and carbon dioxide at high temperatures (impurities are removed), and calcium oxide is put into water to form calcium hydroxide (soaking). The calcite calcium carbonate can be obtained by blowing carbon dioxide while controlling the conditions (temperature, concentration, degree of stirring) as in the following reaction formula.
Ca (OH) ₂ + CO ₂ → CaCO ₃ + H ₂ O

Aragonite-based calcium carbonate is almost the same as the method for producing calcite-based calcium carbonate, and aragonite-based calcium carbonate can be obtained by adjusting the reaction conditions during the production. For example, as shown in the following reaction formula, using slaked lime and water in a causticization reaction tank, stirring and mixing with a stirrer equipped with a stirring blade to prepare lime milk, the sodium carbonate addition rate, addition time, and temperature conditions are appropriately set It is obtained by adjusting to cause a causticizing reaction.
Na ₂ CO ₃ + CaO + H ₂ O → CaCO ₃ + 2NaOH

The oil chestnut calcium carbonate used in the present invention has an oil absorption amount of 150 mL / in accordance with “Pigment Test Method—Part 13: Oil Absorption—Section 1: Refined Sesame Oil Method” described in JIS K 5101-13-1. It is preferable that it is 100 g or more, the BET specific surface area is 50 m ² / g or more, and the volume average particle diameter is 1.8 to 10 μm.

  If the amount of oil absorption of Hikari chestnut calcium carbonate is less than 150 mL / 100 g, for example, there may be a decrease in opacity of white paper and an increase in bleeding in cold-set offset printing, while if it exceeds 250 mL / 100 g, The vehicle component may penetrate into the paper and make it difficult to obtain an excellent printing density. Therefore, the amount of oil absorption of Oguri calcium carbonate is preferably 150 mL / 100 g or more, more preferably 160 mL / 100 g or more, and preferably 250 mL / 100 g or less, and more preferably 240 mL / 100 g or less.

If the BET specific surface area of Oguri calcium carbonate is less than 50 m ² / g, voids in the agglomerated structure may decrease, which may reduce ink absorbency. On the other hand, if it exceeds 150 m ² / g, dilution of the filler dispersion may occur. There is a possibility that operability may be lowered due to increase in viscosity, and drying of the cold-set offset ink taken in may be deteriorated, resulting in scumming stains or print set-off. Therefore, the BET specific surface area of potato chestnut calcium carbonate is preferably 50 m ² / g or more, more preferably 60 m ² / g or more, and preferably 150 m ² / g or less.

  In addition, in this specification, the BET specific surface area of Oguri calcium carbonate means the value measured with the fully automatic BET specific surface area measuring device (model number: Frosorb 2300, Shimadzu Corporation make).

  When the volume average particle diameter of the potato chestnut calcium carbonate is less than 1.8 μm, when added as a filler, it becomes easy to enter the gaps between the pulp fibers constituting the paper, and the potato chestnut calcium carbonate has a bulky paper configuration. As a result, the printability may be reduced, and if it exceeds 10 μm, the contact area with the pulp fiber decreases, and as a result, paper dust is generated at the paper making stage and the printing stage. Or printability may be reduced. Therefore, the volume average particle diameter of the calcium chloride calcium carbonate is 1.8 μm or more, more preferably 2.3 μm or more, particularly preferably 3 μm or more, and 10 μm or less, further 9.6 μm or less, particularly 9 μm or less. Is preferred.

In the present specification, the volume average particle size of Hashikari calcium carbonate is measured for the particle size distribution of a dispersion solution in which 10 mg of a sample is added to 8 mL of a methanol solution and dispersed for 3 minutes with an ultrasonic disperser (output: 80 W). It means a value measured with an apparatus (laser type microtrack particle size analyzer, manufactured by Nikkiso Co., Ltd.).

  Furthermore, the aspect ratio (the ratio between the major axis and the minor axis of the particles (major axis / minor axis)) of Higurashi calcium carbonate is 3.3 or less, further 3 in view of further improving the opacity and printability of newsprint. Is preferably not more than 0.0, and more preferably not less than 2.1, and more preferably not less than 2.3, from the viewpoint of sufficiently suppressing a decrease in paper strength of newsprint.

  In the present invention, in order to uniformly disperse the three kinds of specific fillers in the raw material pulp, for example, the calcium chloride calcium carbonate obtained as described above is preferably 10% by mass or less, more preferably 2% in advance. It is desirable to make paper by diluting and dispersing to a concentration of 10 to 10% by mass, particularly preferably 3 to 9% by mass, and internally adding the diluted solution into the raw material pulp.

  Calcium carbonate (B) can be added to the raw pulp in any machine chest, fan pump, and suction to paper machine inlet, but it further improves printability and printing opacity in web offset printing. For this purpose, it is effective to add calcium carbonate (B) before the fan pump.

(C) Recycled particles Recycled particles (C), which is one of the fillers, are inorganic particles obtained by using papermaking sludge as a main raw material, and through a dehydration process, a drying process, a combustion process, and a pulverization process.

  The papermaking sludge used as a raw material is not particularly limited, and among these, deinking floss discharged in the deinking process of the used paper processing process for producing used paper pulp is particularly preferable.

  Recycled particles obtained by burning deinked floss are those that can be circulated, so there is no need to dispose of landfills as waste, which greatly contributes to reducing environmental impact and saving resources. It is. In addition, when the main raw material is deinking floss generated in the deinking process of the used paper processing process, there is an advantage that it is inexpensive, the amount of new natural inorganic minerals can be suppressed, and the manufacturing cost is sufficiently reduced. is there. Furthermore, by using such regenerated particles, the yield of ash during papermaking is high, there is no deterioration in wear of papermaking equipment such as wire wear, and the resin component is adsorbed to the regenerated particles in a fine state. Thus, it is possible to prevent pitch troubles due to agglomeration of the resin, hardly cause soiling of the papermaking equipment, and to produce newsprint with low cost and high operability.

  In addition, when manufacturing the said reproduction | regeneration particle | grains, you may pass through the granulation process of a deinking floss, the classification process provided between each process, etc. so that it may mention later. In addition, it is desirable to provide various sensors in the production facility for regenerated particles to control the state of the object to be processed and the equipment, the processing speed, and the like. Various flow paths such as a transfer flow path, a supply flow path, a delivery flow path, a circulation flow path, and a return flow path shown in the following specific description can be constituted by, for example, a pipe, a duct, or the like.

  In particular, the deinking floss discharged in the waste paper recycling process is made of a material derived from papermaking raw materials, and is less contaminated with impurities such as iron and other heavy metals, and thus is suitable as a main raw material for the regenerated particles. In the used paper recycling process, the used paper itself is selected in advance, so that the deinking floss has a stable inorganic composition over time, and the resulting recycled particles have a stable composition. These deinking froths contain, for example, calcium carbonate, kaolin, talc, titanium dioxide, silica, alumina and the like as inorganic substances. In addition, it is preferable that the ratio of the deinking froth in all the raw materials of reproduction | regeneration particle | grains shall be 50 mass% or more as a solid content, Furthermore, 60 mass% or more.

In the present invention, the deinking floss as described above is used as the papermaking sludge, and at least the first combustion process and the second combustion process are performed as the combustion process, and combustion is performed at a temperature of 300 ° C. or more and less than 500 ° C. in the first combustion process. It is preferable to use the treated regenerated particles as regenerated particles (C). Therefore, the combustion process, particularly the first combustion process, will be briefly described before the detailed description of the four production steps of the regenerated particles.

  For example, in the case of burning papermaking sludge, (1) Japanese Patent Application Laid-Open No. 2003-119695 discloses an oxygen-deficient state in which oxygen is not present substantially in an oxygen concentration of 0.1% by volume or less in a furnace. Specifically, drying and carbonization in an indirect heating furnace (external heat combustion furnace), then deoxidizing carbon derived from organic matter contained in the carbide, specifically whitening in an indirect heating furnace A method of processing has been proposed. The publication also discloses the use of an internal heat rotary kiln furnace in the latter whitening treatment.

  On the other hand, (2) JP 2002-275785 also discloses the use of a rotary kiln furnace for recombustion after carbonization.

  Further, in (3) Japanese Patent No. 3808852, deinking sludge is used as a raw material sludge, and the drying process is performed, and the dried deinking sludge is supplied into the furnace from the upper part of the cyclone combustion furnace. A primary combustion process for obtaining a primary combustion product containing unburned matter by burning while swirling and lowering, and a mechanical combustion in communication with the cyclone type combustion furnace and receiving the primary combustion product containing unburned content from its lower end A secondary combustion process in which the heat of combustion in the primary combustion process is used to promote combustion until the predetermined whiteness is achieved while promoting contact with oxygen by vigorous stirring, and the white pigment or white filler from the deinking sludge. Manufacturing methods have been proposed.

  Also, (4) Japanese Patent Application Laid-Open No. 2004-176208 proposes a method of drying, carbonizing, and burning molded sludge in one rotary kiln furnace when producing filler from wastewater treatment sludge in the coated paper manufacturing process. Has been.

  The methods described in the above (1), (2) and (4) are not based on deinking floss separated from pulp fibers in the deinking process of the used paper processing facility for producing used paper pulp, The sludge is used as a main raw material, and the regenerated particles obtained are considered to be different from the regenerated particles used in the present invention.

  On the other hand, according to the method described in (3), regenerated particles substantially the same as the regenerated particles used in the present invention can be obtained. In this method, a cyclone fluidized combustion furnace is used to burn dry matter. Then, secondary combustion is performed.

  When using a cyclonic fluidized combustion furnace in the combustion process, it is thought that it is derived from its own form, but in the cyclone type, raw materials and air of tens to hundreds of microns are generally supplied from the supply port as a swirling flow. The raw material is burned by being effectively mixed with air by the swirling action of air. Therefore, the fine particles contained in the raw material are discharged out of the system together with the exhaust gas, resulting in a decrease in product yield, and the burning time (heating time) of the deinking floss that is the main raw material is short, so unburned components are likely to occur. The quality, particularly the shape, of the finally obtained combustion product is not constant, and the whiteness of the combustion product may vary.

  Therefore, the first combustion furnace is provided for at least two stages of combustion processes, including a first combustion furnace, and a second combustion furnace that burns again the deinking floss burned in the first combustion furnace. In the above, for example, by performing the combustion treatment at a relatively low temperature of 300 ° C. or higher and lower than 500 ° C., excessive combustion does not occur, and regenerated particles with more stable quality can be produced.

Specifically, the raw material after dehydration is dried and burned in series, and the combustion time (residence time) in the first combustion furnace by internal heat exceeds 30 minutes and is 90 minutes or less, more preferably 40 to 80. Minutes, optimally 50-70 minutes. Further, the raw material after dehydration is dried and burned (primary combustion) by an internal heat (direct heating) kiln furnace in which the main body is placed horizontally and rotates around the central axis, and then combustion obtained from the first combustion furnace The product is combusted again (secondary combustion) in a second combustion furnace with external heat, and the combustion time (residence time) is 60 minutes or more, more preferably 60 to 240 minutes, particularly preferably 90 to 150 minutes, Optimally, it is desirable to be 120 to 150 minutes. Further, it is more preferable to perform secondary combustion in an external heat (indirect heating) kiln furnace in which the main body is placed horizontally and rotates around the central axis, particularly an external heat electric furnace in which the combustion temperature can be easily adjusted.

  In the method for producing regenerated particles, which will be described later with reference to the drawings, an internal heat kiln furnace is exemplified as the first combustion furnace, and an external heat kiln furnace is exemplified as the second combustion furnace. A combustion furnace can be used. Moreover, it is not limited to a kiln furnace, Well-known combustion furnaces, such as a fluidized bed furnace, a stalker furnace, a cyclone furnace, a semi-dry distillation / negative pressure combustion type furnace, can be used. In the present invention, any known combustion furnace can be used as long as it is at least a two-stage combustion furnace in which the first primary combustion is performed in the first combustion furnace using internal heat and the subsequent secondary combustion is performed in the second combustion furnace using external heat. These combustion furnaces can also be suitably used. Further, as the second combustion furnace using external heat, a known combustion method using an indirect heating type combustion furnace using heavy oil or the like as a heat source may be employed.

  In the internal heat kiln furnace that is preferably used as the first combustion furnace, drying and combustion can be performed in one furnace, and drying and combustion proceed slowly and stably from the supply port to the discharge port, and Combustion is prevented from being pulverized. Further, when combustion is performed in an external heat kiln furnace that is preferably used as the second combustion furnace, the combusted material after the primary combustion is subjected to secondary combustion with a predetermined residence time from the end portion thereof, and then from the discharge port of the other end portion. Further, since uniform heat is applied to the combustion product by the external heat, the combustion is performed uniformly and there is no variation in the combustion. Furthermore, since the combustion product is gently stirred by friction caused by rotation of the inner wall of the kiln furnace, pulverization is unlikely to occur. As a result, the quality and shape of the final combustion product becomes more stable.

  For example, as described above, in the first combustion furnace, in order to efficiently burn fine fibers in the raw material, latex that is an organic polymer compound frequently used for coated paper, ink components applied by printing, etc., A method of dehydrating and drying the rate to less than 40% and combusting at a high temperature can be adopted. In the first combustion furnace, for example, by performing a heating operation at a relatively low temperature of 300 ° C. or more and less than 500 ° C., The organic matter contained in is converted into combustion gas, and the combustion gas is burned (oxidized), whereby the quality stability and whiteness of the obtained regenerated particles are further improved.

  Thus, drying and combustion in the combustion process are preferably performed in an internal heat kiln furnace and an external heat kiln furnace in at least a two-stage combustion furnace, so that regenerated particles having more uniform and excellent stability can be obtained. Obtainable.

  An internal heat kiln furnace or an external heat kiln furnace used as a suitable combustion furnace can lift and agitate the combusted material without slipping by making the internal refractory into a hexagonal or octagonal shape instead of a circumferential shape. However, in reality, the kiln furnace has a cylindrical shape, and it is optimal to provide a lifter for stirring the combusted material in terms of uniform combustion of the raw materials and uniform quality. This is also considered to be related to intentionally burning the entire raw material slowly at a low temperature in the first combustion furnace.

  Further, a combustion furnace for obtaining more suitable regenerated particles will be described below.

  Conventionally used combustion furnaces can be broadly classified into four types: stalker furnaces (fixed bed), fluidized bed furnaces, cyclone furnaces, and kiln furnaces.

(Stoker furnace (fixed floor))
It is difficult to adjust the degree of combustion of the deinking floss, the combustibles are likely to be non-uniform, and the combustion of the deinking floss with a large amount of ash causes dust to fall due to the clearance between the grate. Since air is blown up and burned under the combustion material through the grate, calcium carbonate or the like becomes fly ash and is sent to the exhaust gas facility together with the exhaust gas, and the yield is likely to decrease.

(Fluidized bed furnace)
Since a particulate fluid medium such as silica sand is used as the fluid medium in the furnace, the silica sand is mixed into the regenerated particles, leading to a decrease in quality. In addition, it is difficult to uniformly stir, and after mixing and burning the cinnabar in a fluidized bed, the cinnabar and the burned material are separated, and the cinnabar is returned to the combustion furnace and only the burned material is taken out. Since the same particle size occurs, it cannot be separated. Furthermore, since combustion is performed in a state of floating with dredged sand, it is difficult to adjust the degree of combustion, resulting in variations in quality. Combustion proceeds while a combustion product passes through a stalker (stepped shape) of a combustion furnace at a predetermined width, so that the ash is not sufficiently stirred and the combustion varies in the width direction. In addition, due to friction and collision with high-hardness silica sand, the combusted material is pulverized and discharged as fly ash, and the yield is reduced.

(Cyclone furnace)
Since it passes through the furnace in an instant, the fixed carbon in the combustion product is not burned sufficiently, leading to a decrease in the whiteness of the regenerated particles. In addition, fine particles are not separated by a cyclone and are sent to the exhaust gas treatment step together with the exhaust gas, resulting in a decrease in yield.

  From these facts, in the present invention, it is most preferable to use a kiln furnace as the combustion furnace. Further, as described above, it is preferable from the following point that the first combustion furnace is an internal heat kiln furnace and the second combustion furnace is an external heat kiln furnace.

  The external heat kiln furnace has a structure in which heating equipment is provided outside the kiln furnace, so the structure of the kiln furnace is relatively complicated, and a large amount of heat source is required to dry and burn the combustion products indirectly. It becomes. Therefore, when the external heat kiln furnace is used as the first combustion furnace in the primary combustion process of drying and burning the raw material having a high water content after dehydration, the drying / combustion efficiency is lowered, and the productivity is lowered. Temperature control becomes difficult and requires a large energy cost, which may reduce cost effectiveness.

  In addition, when the internal heat kiln furnace is used as the second combustion furnace, a large amount of diluted air is required to adjust the furnace temperature when the remaining carbon is burned. It is difficult to transfer heat uniformly into the internal heat kiln furnace. In addition, since it is difficult to suppress fluctuations in the furnace temperature, overburning and combustion unevenness of the combustion products are likely to occur. In addition, heavy fuel oil burner used for normal heating is contaminated with heavy fuel combustion residual carbon and sulfur oxides, resulting in decreased whiteness and variation at the product stage, making it difficult to equalize the quality of the resulting combustion product There is also a risk of becoming.

  For these reasons, in the present invention, it is optimal to use the first combustion furnace as the internal heat kiln furnace and the second combustion furnace as the external heat kiln furnace in the combustion process.

  Next, an example of a more preferable method for producing regenerated particles used in the present invention will be described in more detail with reference to the drawings.

[Overview]
The production facility flow of the regenerated particles includes a dehydration step, a drying step, a combustion step, and a pulverization step. Further, a deinking floss agglomeration step or granulation step, a classification step or the like may be provided between the steps.

  FIG. 1 is a schematic diagram illustrating a partial configuration example (an example of equipment including a drying process, a combustion process, and a combustion process) of a production facility flow for regenerated particles. This equipment is equipped with various sensors, and controls the state of combustibles, equipment, and processing speed.

  The deinking floss separated from the pulp fiber in the deinking process for producing waste paper pulp (not shown) is dehydrated by a known dehydration equipment (not shown) through various operations. The material after dehydration is desirably 35% by mass or more, preferably less than 90% by mass, more preferably 45 to 70% by mass, particularly preferably more than 50% by mass and 60% by mass or less.

  The material 10 after such dehydration is desirably pulverized to a particle size of 40 mm or less by a pulverizer (or pulverizer). The raw material 10 is cut from the storage tank 12 and charged by a charging machine 15 from one side of the first combustion furnace 14 which is an internal heat kiln furnace in which the main body is placed horizontally and rotates around the central axis. An exhaust gas chamber 16 is provided on one side of the first combustion furnace 14, and an exhaust chamber 18 is provided on the other side. The raw material 10 is passed through the discharge chamber 18, hot air is blown from the other side of the first combustion furnace 14, charged from the one side, and sequentially transferred to the other side as the first combustion furnace 14 rotates. Is dried and burned.

  Here, it is desirable to prepare the hot air blown into the first combustion furnace 14 so that the oxygen concentration becomes 0.1 to 20%. The in-furnace temperature is preferably 300 ° C. or higher and lower than 500 ° C., preferably 400 ° C. or higher and lower than 500 ° C., particularly 400 to 450 ° C. Hot air is blown from a hot air generating furnace 20 provided with a burner 20A.

  From the exhaust gas chamber 16, exhaust gas subjected to drying and combustion is sent into the recombustion chamber 22. The fine powder of the combustion material contained in the exhaust gas is discharged from the lower part of the exhaust gas chamber 16 and reused. The exhaust gas is recombusted by the burner in the recombustion chamber 22, precooled by the precooler 24, passed through the heat exchanger 26, and discharged from the chimney 30 by the induction fan 28. Here, after raising the temperature of the outside air, the heat exchanger 26 is sent to the hot air generating furnace 20 and used for the hot air blown from the first combustion furnace 14 to recover the heat of the exhaust gas from the exhaust gas chamber 16. . The treatment of exhaust gas is effective for removing harmful substances contained in the exhaust gas.

  Combustion products that have undergone drying and combustion treatment in the first combustion furnace 14 are charged into a second combustion furnace 32 that is an external heat kiln furnace in which the main body is placed horizontally and rotates around the central axis. The particle size of the combusted material to be charged is preferably 40 μm or less. As a heat source in the second combustion furnace 32, it is preferable to adjust by electricity so that temperature control in the second combustion furnace 32 is easy and temperature control in the longitudinal direction is easy. Therefore, it is desirable that the externally heated second combustion furnace 32 is configured to again burn the combustion product obtained from the first combustion furnace 14 indirectly by an electric heater.

  In the second combustion furnace 32, the oxygen concentration is 5 to 20%, preferably 10 to 20%, particularly 10 to 15% by an air or oxygen supply mechanism (not shown) for adjusting the oxygen concentration. It is desirable to burn. The combustion temperature is 550 to 780 ° C, preferably 600 to 750 ° C. Further, the residence time in the second combustion furnace is preferably 60 minutes or longer, preferably 60 to 240 minutes, particularly 90 to 150 minutes, and 120 to 150 minutes for complete combustion of the remaining carbon. Is optimal.

The regenerated particles that have been burned are cooled by a cooler 34, and then sorted by a particle size sorter 36 such as a vibration sieve, and the combustion is adjusted to a target particle size in a grinding process using a wet grinding machine or the like. The material is temporarily stored in the combustible product silo 38 and is sent to the use destination of the filler.

  In addition, although the case where only the deinking floss was used as the raw material in the above-mentioned process was illustrated, the combustion product using the deinking floss as a main raw material and the raw material obtained by appropriately mixing other papermaking sludge such as papermaking sludge in the papermaking process It may be.

  The outline of the method for producing regenerated particles has been described above, and details and application examples thereof will be described below.

[material]
In the used paper pulp manufacturing process, in order to continuously produce used paper pulp of stable quality, used paper is selected and selected, and used paper of a certain quality is used. For this reason, the types, ratios, and amounts of inorganic substances brought into the waste paper pulp manufacturing process are basically constant. Moreover, even when plastics such as vinyl film, which cause fluctuations in unburned materials in the method for producing regenerated particles, are contained in the waste paper, these foreign substances are the pre-stage leading to the deinking process to obtain deinking floss Can be removed. Accordingly, the deinking floss is a raw material for producing regenerated particles having extremely stable quality as compared with papermaking sludge generated in other processes such as a factory drainage process and a papermaking raw material preparation process.

  In the present specification, deinking floss refers to what is separated from pulp fibers in a used paper processing process for producing used paper pulp, mainly in a deinking process for removing ink adhering to used paper.

[Dehydration process]
For further dehydration of the deinking floss, known dehydration means can be appropriately used. In an example in the present embodiment, water is separated from the deinking floss by a screen, for example, and dehydrated. In the screen, the deinking floss dehydrated to 90 to 97% by mass is preferably sent to, for example, a screw press and further dehydrated to a predetermined moisture content.

  If the water content of the raw material after dehydration exceeds 70% by mass, the temperature of the drying / combustion treatment in the first combustion furnace will be lowered, the energy loss for heating will be great, and the uneven combustion of the raw material will easily occur. It becomes difficult to promote uniform combustion. Furthermore, the moisture in the exhaust gas discharged increases, and there is a risk that the recombustion treatment efficiency in dioxin countermeasures will be reduced and the load on the exhaust gas treatment equipment will be increased. Moreover, when the moisture content of the raw material after dehydration is as low as less than 35% by mass, it causes excessive combustion of the deinking floss. By appropriately adjusting the moisture content of the raw material after dehydration, it is possible to contribute to the reduction of dehydration energy.

  As described above, if deinking of the deinking floss is performed in a multi-stage process and abrupt dewatering is avoided, the outflow of inorganic substances can be suppressed, and there is no fear that the flocs of the deinking floss become too hard. In the dehydration treatment, an auxiliary agent for improving the dehydration efficiency such as an aggregating agent for aggregating the deinking floss may be added, but it is preferable to use an aggregating agent that does not contain iron. If iron is contained, the whiteness of the regenerated particles may decrease due to oxidation of the iron.

  The deinking process of the deinking floss is preferably adjacent to the recycled particle manufacturing process in terms of production efficiency, but it is also possible to transport the dehydrated product by providing equipment adjacent to the waste paper pulp manufacturing process in advance. It is conveyed to a fixed quantity feeder by a conveyance means such as a truck or a belt conveyor, and supplied to the drying / combustion process from this fixed quantity feeder.

In the operation of supplying the raw material 10 after dehydration to the first combustion furnace 14, it is preferable that the average particle size is adjusted to a particle size of 40 mm or less by a pulverizer (or a pulverizer).
More preferably, the average particle diameter is adjusted to 3 to 30 mm, and further preferably, the average particle diameter is adjusted to be in the range of 5 to 20 mm. Furthermore, it is more preferable to grind so that the ratio of the raw material 10 whose particle diameter is 50 mm or less becomes 70 mass% or more. In order to achieve a combustion treatment that does not cause a heat change of the calcium carbonate contained in the deinking floss, it is preferable that the particle diameter of the raw material is uniform, but if the average particle diameter is less than 3 mm, overcombustion tends to occur. On the other hand, when the average particle diameter exceeds 40 mm, it is difficult to achieve uniform combustion up to the raw material core.

  In the present specification, the average particle diameter and the ratio of the particle diameter are values measured using a sample solution sufficiently dispersed by a stirring type disperser, and the particle diameter in each combustion stroke is JIS Z 8801. -2 (2000) A value measured with a metal plate sieve having a pore size of 1 mm unit as defined in “Test Sieve—Part 2: Metal Plate Sieve”.

  Moreover, in this invention, between the said spin-drying | dehydration process and the following drying process, shower water is preferably contained, and raw material water | moisture content can be adjusted to a fixed ratio in the range of 40-85 mass% in moisture content. preferable. Thus, when low-temperature firing is performed, the raw material is adjusted to a predetermined range in advance, and moisture is contained in a predetermined ratio, thereby preventing overburning of the raw material while volatilizing the combusted material contained therein. The effect of promoting combustion gasification and promoting homogeneous combustion can be brought about.

[First combustion process (drying / combustion process)]
The raw material 10 is cut out from the storage tank 12 and supplied to the first combustion furnace 14. The first combustion furnace 14 has an internal heat kiln furnace system in which a main body is placed horizontally and rotates around a central axis, and is charged by a charging machine 15 from one side of the first combustion furnace 14 (internal heat kiln furnace 14). The Hot air generated in the hot air generating furnace is sent from the discharge port side of the internal heat kiln furnace 14 so as to counter-current with the flow of the dehydrated product, and the internal heat kiln furnace 14 is heated. An exhaust gas chamber 16 is provided on one side of the internal heat kiln furnace 14, and an exhaust chamber 18 is provided on the other side. Hot air is blown from the other side of the internal heat kiln furnace 14 through the discharge chamber 18, charged from the one side, and sequentially transferred to the other side as the internal heat kiln furnace 14 rotates. Drying and burning takes place.

  That is, in this drying / combustion step, the dehydrated product is dried and burned gently from the supply port to the discharge port by drying and burning in an internal heat kiln furnace in which the main body is placed horizontally and rotates around the central axis. Combustion of organic content, suppression of pulverization of combustibles, stable control of the degree of combustion and particle size of dehydrated products with various properties such as formation of aggregates, hard and soft Can do. In addition, it is also possible to divide drying into another process and to put in a blow-up type dryer.

  Here, the hot air blown into the internal heat kiln furnace 14 is preferably adjusted so that the oxygen concentration is 0.1 to 20%, further 1 to 17%, particularly 7 to 15%.

  Since oxygen is consumed by the combustion (oxidation) of the raw material, the oxygen concentration varies depending on the state of combustion. When the oxygen concentration is excessively low, it is difficult to achieve sufficient combustion. The oxygen concentration in the combustion furnace decreases as oxygen is consumed due to the combustion of the raw material, etc., but the oxygen concentration is increased by blowing or exhausting oxygen-containing gas such as air by a hot air generator for combustion. It is also possible to finely adjust the temperature in the combustion furnace by blowing or exhausting oxygen-containing gas, and the raw material can be uniformly burned without unevenness. it can.

The furnace temperature (combustion temperature) of the first combustion furnace is preferably 300 ° C. or higher and lower than 500 ° C., more preferably 400 ° C. or higher and lower than 500 ° C., and particularly preferably 400 to 450 ° C. In the first combustion furnace, it is preferable to combust in a temperature range of 300 ° C. or more and less than 500 ° C. for the purpose of slowly burning organic substances that can be easily combusted and suppressing the generation of residual carbon that is difficult to combust. If the combustion temperature is excessively low, the organic matter may be insufficiently combusted. If the combustion temperature is excessively high, overcombustion occurs, and calcium oxide is easily generated due to decomposition of calcium carbonate. Furthermore, when the temperature of the hot air is 500 ° C. or higher, drying / combustion proceeds locally faster than the particle alignment of the burned material having various properties such as hard and soft, so that the unburned surface of the particles It becomes difficult to make the difference between the rate and the internal unburned rate small and uniform.

  In addition, a hot air is blown in from the hot air generation furnace 20 provided with 20 A of burners.

  From the exhaust gas chamber 16, exhaust gas subjected to drying and combustion is sent into the recombustion chamber 22. The fine powder is discharged from the lower part of the exhaust gas chamber 16, and is mixed again with the raw material and reused.

  The exhaust gas is recombusted by the burner in the recombustion chamber 22, precooled by the precooler 24, passed through the heat exchanger 26, and discharged from the chimney 30 by the induction fan 28. Here, after raising the temperature of the outside air, the heat exchanger 26 is sent to the hot air generating furnace 20 and is used for hot air blown from the internal heat kiln furnace 14 to recover the heat of the exhaust gas from the exhaust gas chamber 16. .

  The first combustion furnace preferably burns with a residence time of 30 to 90 minutes under the above conditions in order to slowly burn the easily combustible organic substances contained in the deinking floss and suppress the formation of residual carbon. Is preferred. A residence time (burning time) of 40 to 80 minutes is more preferable in terms of organic combustion and production efficiency, and a residence time (burning time) of 50 to 70 minutes ensures constant quality. Is particularly preferable. If the combustion time is less than 30 minutes, sufficient combustion may not be performed and the proportion of residual carbon may increase. On the other hand, if the combustion time exceeds 90 minutes, thermal decomposition of calcium carbonate due to overcombustion of the raw material may occur, and the resulting regenerated particles may become extremely hard.

  In particular, it is preferable to dry and burn so that the unburned rate of the combustion product supplied in the second combustion step of the next step is 2 to 20% by mass, and the unburned rate is more preferably 5 to 17% by mass. %, Particularly preferably 7 to 12% by mass.

  As described above, by setting the unburned rate of the combustion product supplied in the second combustion step to 2 to 20% by mass, combustion in the second combustion step can be efficiently performed in a short time, By stable heating in the external heating furnace, it is possible to obtain a high whiteness combustion product having a low hardness and a whiteness of 80% or more, at least 70% or more. In particular, if the unburned rate of the combustion material supplied in the second combustion process is less than 2% by mass, the energy cost in the primary combustion furnace may be high and the hardness of the combustion material may be relatively high. In some cases, the quality of the combustion product may be reduced, such as a decrease in the whiteness of the combustion product at the outlet of the second combustion furnace.

[Second combustion process]
Combustion products that have undergone drying and combustion treatment in the internal heat kiln furnace 14 are loaded into an external heat kiln furnace corresponding to a second combustion furnace 32 having an external heat jacket 31 that rotates horizontally around the central axis through a transfer channel. Entered. In the second combustion furnace 32 (external heat kiln furnace 32), while the combustion product is heated with external heat, the transfer of the raw material in the combustion furnace is controlled by a lifter provided on the inner wall of the kiln furnace, and the combustion is performed slowly. As a result, the unburned portion is burned more uniformly.

In the combustion in the second combustion furnace, the residual organic matter that could not be combusted in the first combustion furnace, for example, residual carbon, was burned, so that the particle diameter was adjusted to be smaller than the particle diameter of the raw material supplied in the first combustion furnace. It is preferable to use a combustion product. It is preferable to adjust the combustion product after the drying / combustion step (combustion product at the inlet of the second combustion furnace) so that the average particle diameter is 10 mm or less, further 1 to 8 mm, and particularly 1 to 5 mm.

  If the average particle diameter of the combustion product at the inlet of the second combustion furnace is less than 1 mm, there is a risk of overcombustion. Conversely, if the average particle diameter exceeds 10 mm, the remaining carbon is difficult to burn and combustion does not proceed to the core. The whiteness of the regenerated particles obtained may be reduced. In order to ensure stable production in the second combustion furnace, it is preferable to adjust the particle size so that the combustion product having an average particle size of 1 to 8 mm is 70% by mass or more. Therefore, it is useful for practical application in terms of uniforming the quality of the obtained regenerated particles. Furthermore, when classification is performed after drying, there is an advantage that combustion products of small-diameter particles can be surely removed and the processing efficiency is improved.

  As an external heat source in the external heat kiln furnace 32, an electric heating type electric furnace in which temperature control in the external heat kiln furnace 32 is easy and temperature control in the longitudinal direction is easy is suitable. Therefore, it is desirable that the external heat kiln furnace 32 is an electric heater.

  By using electricity for external heat, it becomes possible to finely adjust the temperature and control the internal temperature uniformly, and the degree of combustion of dehydrated products with various properties such as formation of aggregates, hard and soft Can be stably controlled.

  Furthermore, the electric furnace can be provided with a temperature gradient arbitrarily by providing a plurality of electric heaters in the flow direction of the furnace, and can maintain the temperature of the combustion product for a certain period of time. Residual organic components in the combustion product that has passed through one combustion furnace, in particular residual carbon, can be brought to zero as much as possible without causing unburned carbon to decompose in the second combustion furnace. In the present invention, such a second combustion furnace is used, and preferably, by using the internal heat kiln furnace as the first combustion furnace, the combustion treatment is performed at a temperature of 300 ° C. or higher and lower than 500 ° C. Uses an internal heat kiln furnace in which the main body is placed horizontally and rotates around the central axis as the first combustion furnace, and the oxygen concentration in the internal heat kiln furnace is adjusted so that the moisture content of the raw material after dehydration is 35% or more. By adjusting the content to 0.1 to 20% and performing the combustion treatment at a temperature of 300 ° C. or higher and lower than 500 ° C., regenerated particles with high whiteness can be finally obtained with a low degree of wire wear.

  In the external heat kiln furnace 32, it is desirable to adjust the oxygen concentration to be 5 to 20%, more preferably 10 to 20%, and most preferably 10 to 15%. The oxygen concentration can be controlled by controlling the amount of oxygen or air input to the second combustion furnace by an appropriate means. However, in FIG. 1, illustration of specific forms is omitted. In particular, if the oxygen concentration in the external heat kiln furnace is less than 5%, there is a possibility that the combustion of residual carbon that is difficult to burn does not proceed.

  The combustion temperature in the second combustion furnace is preferably 550 to 780 ° C, more preferably 600 to 750 ° C. In the second combustion furnace, as described above, since it is necessary to burn the residual organic matter that has not been burned in the first combustion furnace, particularly the residual carbon, it is preferable to burn at a higher temperature than the first combustion furnace. If the combustion temperature in the second combustion furnace is less than 550 ° C., it is difficult to sufficiently burn the residual organic matter. Conversely, if the combustion temperature exceeds 750 ° C., the oxidation of calcium carbonate in the combustion product proceeds. The particles may become hard.

  In this specification, the combustion temperature (primary combustion temperature) in the first combustion furnace is the outlet temperature of the first combustion furnace, and the combustion temperature (secondary combustion temperature) in the second combustion furnace is a radiation thermometer. Based on the inner wall surface temperature of the second combustion furnace.

The residence time in the second combustion furnace is preferably 60 minutes or longer, more preferably 60 to 240 minutes, particularly preferably 90 to 150 minutes, and most preferably 120 to 150 minutes. In particular, the remaining carbon must be burned slowly at a high temperature that does not cause decomposition of calcium carbonate as much as possible. If the residence time in the second combustion furnace is less than 60 minutes, the burning of the remaining carbon is not possible in a short time. On the contrary, if it exceeds 240 minutes, calcium carbonate may be decomposed. In order to perform stable production of the combustion products, it is preferable that the residence time is 60 minutes or longer, and in order to prevent overcombustion and ensure productivity, it is preferable to burn the residence time in 240 minutes or less.

  The average particle diameter of the combustion product discharged from the external heat kiln furnace 32 (combustion product at the second combustion furnace outlet) is preferably adjusted to 10 mm or less, more preferably 1 to 8 mm, and most preferably 1 to 4 mm. It is.

  The regenerated particles that have been combusted are cooled by the cooler 34 and then temporarily stored in the combusted product silo 38 by a particle size selector 36 such as a vibrating sieve to be used as a filler application destination. It is done.

[Crushing process]
The combusted product (regenerated particles) having undergone the second combustion step is further finely granulated to a necessary particle size in a known dispersion / pulverization step, and used as a raw material pulp filler.

  For example, after combustion in the second combustion step, the obtained particles are pulverized using a dry pulverizer such as a jet mill or a high-speed rotary mill, or a wet pulverizer such as an attritor, a sand grinder, or a ball mill. The regenerated particles used as a filler in the present invention are preferably aggregates having a volume average particle diameter of 5 to 15 μm, as will be described later.

[Attached process]
For example, in the production facility for regenerated particles shown in FIG. 1, in order to obtain more stable quality, it is preferable to classify the regenerated particles so that the particle diameter is uniform in each step. By feeding back coarse particles and fine particles to the previous process, quality can be further stabilized.

  In addition, it is preferable to granulate the deinked floss that has been subjected to dehydration in the previous stage of the drying process, and it is more preferable to classify the granulated product so as to have a uniform particle diameter. Again, the quality can be further stabilized by feeding back coarse granulated particles and fine granulated particles to the previous process. Known granulation equipment can be used for granulation, and equipment of a rotary type, a stirring type, an extrusion type, etc. are suitable.

  In addition, it is preferable to remove in advance those that can be used as raw materials for recycled particles. For example, sand, plastic foreign matter, metal, etc. are removed with a pulper, screen, cleaner, etc. before the deinking process in the waste paper pulp manufacturing process. It is preferable in terms of removal efficiency. In particular, iron oxide is a causative substance for reducing the whiteness of the fine particles. Therefore, it is recommended to avoid the iron content and selectively remove it. Each process is designed or lined with materials other than iron to prevent iron from being mixed into the system due to wear, etc., and a high magnetic material such as a magnet is installed in the drying / classifying equipment, etc. It is preferable to remove iron.

  An internal heat kiln furnace or an external heat kiln furnace used as a suitable combustion furnace can lift and agitate the combusted material without slipping by making the internal refractory into a hexagonal or octagonal shape instead of a circumferential shape. However, in reality, the kiln furnace has a cylindrical shape, and it is optimal to provide a lifter for stirring the combusted material in terms of uniform combustion of the raw materials and uniform quality. This is also considered to be related to intentionally burning the entire raw material slowly at a low temperature in the first combustion furnace.

[About the lifter of the second combustion furnace]
By arranging a helical lifter and / or a parallel lifter parallel to the axial center from the one end side to the other end side on the inner wall in the second combustion furnace, uniform combustion of the raw material and uniform quality Can be achieved. In particular, it is desirable to dispose the spiral lifter and the parallel lifter parallel to the axial center from the charging side to the discharge side of the combusted material.

  According to the structure of the lifter, the contents introduced from the charging side are first lifted while being fed by an appropriate amount toward the other end side by the spiral lifter, and dropped, and the organic components resulting from the raw material Gasifies and efficiently contacts with the generated combustion gas (combustible gas), and further contacts the combustion gas (combustible gas) efficiently by repeating the operation of being lifted and dropped by a parallel lifter. Therefore, the contents can be combusted efficiently with heat exchange. In particular, the amount of content fed into the parallel lifter is controlled by the spiral lifter, so that the content is properly lifted and dropped at the parallel lifter portion, and the content is burned uniformly and efficiently. be able to. Further, since there is no fear of damage to the refractory, there is no decrease in the purity of the combustion product, and its production capacity is improved.

  In addition, when the spiral lifter and the parallel lifter are made of metal such as a stainless steel plate having heat resistance, for example, since the temperature is relatively low, sufficient durability and strength can be secured without using expensive heat-resistant materials. In addition, since the heat transfer efficiency is higher than that of a refractory lifter or the like, the heat efficiency is further improved.

  By providing a lifter in the second combustion furnace, it is possible to produce regenerated particles with less hard material, and to reduce frictional resistance.

  The lifter of the second combustion furnace will be described with reference to the drawings. FIG. 2 is a partial schematic view of the second combustion furnace, (a) is a partially broken schematic cross-sectional view of the second combustion furnace, and (b) is a schematic plan view of an internal development of the second combustion furnace. In FIG. 2, the combusted material is charged from the left side of the second combustion furnace 32 (shown as “charging” in FIG. 2A), and is configured to be rotationally driven by a rotational driving means (not shown). And discharged from the other end.

  The second combustion furnace 32 is configured by lining a fireproof wall 32B made of fireproof castable or fireproof brick on the inner surface of a cylindrical outer casing 32A. On the inner surface of the refractory wall 32B of the second combustion furnace 32, a plurality of spirals (eight in FIG. 2) are inclined at an inclination angle of 45 to 70 ° with respect to the axis of the second combustion furnace 32 on the input side. The lifters 4 are projected at equal intervals. Further, a plurality of parallel lifters 5A having appropriate lengths parallel to the axis of the second combustion furnace 32 are provided at equal intervals in the circumferential direction on the other end side of the region where the spiral lifters 4 are disposed (eight in FIG. 2). ) And a plurality of rows (eight rows in FIG. 2) arranged in a staggered manner in the axial direction.

  Further, the parallel lifter 5A is continuously formed on the right side of FIG. 2 toward the discharge portion (not shown). In this case, since the temperature is low on the charging side, the parallel lifter 5A on the charging side is preferably formed of a metal plate having heat resistance and corrosion resistance, such as a stainless steel plate, and becomes high on the discharge side. Therefore, it is desirable that the parallel lifter 5A on the discharge part side has refractory properties.

  In FIG. 2, the spiral lifter 4 is fixedly disposed on mounting brackets 6 disposed at appropriate intervals in the longitudinal direction. Further, each parallel lifter 5A is fixedly disposed on each mounting bracket 5B.

  Furthermore, it is possible to provide only one of a spiral lifter or a parallel lifter as required.

[Silica coating]
As mentioned above, although an example of the suitable manufacturing method of the regenerated particle | grains which are fillers was demonstrated in detail, in this invention, the surface of the regenerated particle obtained through the above processes as this regenerated particle was coat | covered with the silica. Silica-coated regenerated particles can also be suitably used.

  Silica-coated reclaimed particles whose surface is coated with silica have a highly porous surface and a large specific surface area, so that the absorption drying property of offset ink is improved and the printing density is sufficiently improved. The printing opacity can be further improved.

  The deinking floss generated in the deinking process of the used paper processing process used in the present invention has a tendency to increase the content of calcium carbonate with the recent neutral papermaking, and the calcium in the regenerated particles obtained. There is a tendency for the ratio to increase. When regenerated particles having a high calcium ratio are used as fillers, the blank paper opacity of the resulting newsprint may be slightly reduced, but the silica-coated regenerated particles having silica deposited on the surface are inorganic for papermaking applications. The function as particles is very high, and the newspaper opacity using the silica-coated regenerated particles as a filler sufficiently improves the blank paper opacity and oil absorption.

  The silica covering the surface of the regenerated particles can be used without particular limitation as long as it is not naturally produced silica but synthetic silica by some chemical reaction. Specific examples include colloidal silica, silica gel, and anhydrous silica. These synthetic silicas make use of excellent properties such as high specific surface area, high gas adsorbing capacity, fineness, permeability to pores and large adsorbing power, high adhesion, and high oil absorption. It is used in a wide range of fields. Among these, colloidal silica is an amorphous silicic acid sol obtained by removing impurities from a silicic acid compound, and stabilizing the sol by adjusting pH and concentration, and has an amorphous shape such as a spherical shape, a chain shape, and an amorphous shape. Silica. Silica gel is hydrous silicic acid obtained by decomposing sodium silicate with an inorganic acid. Anhydrous silica is obtained by hydrolysis of silicon tetrachloride.

  Silica-coated regenerated particles can be obtained by suspending the regenerated particles obtained in the combustion step in an alkali silicate solution and adding mineral acid, and coating the periphery of the regenerated particles with silica. This method can be suitably employed.

  First, regenerated particles are added to and dispersed in an alkali silicate solution, and after preparing a slurry, while heating and stirring, the liquid temperature is maintained at about 70 to 100 ° C., more preferably at a predetermined pressure in an airtight container, and the mineral acid is added. Add to produce silica sol. Subsequently, silica can be deposited on the surface of the regenerated particles by adjusting the pH of the final reaction solution to a range of about 8-11. Silica deposited on the surface of the regenerated particles in this way is hydrolyzed by reacting at high temperature with a dilute solution of mineral acid such as sulfuric acid, hydrochloric acid, nitric acid, etc. using alkali silicate (eg, sodium silicate: water glass) as a raw material. Silica sol particles having a particle size of about 10 to 20 nm obtained by reaction and polymerization of silicic acid.

  In addition, silica sol microparticles with a particle size of about several nanometers produced by adding a mineral acid such as dilute sulfuric acid to an alkali silicate solution such as a sodium silicate solution so as to cover the entire porous surface of the regenerated particles. The silica may be deposited on the surface of the inorganic particles by bonding between the silica sol fine particles on the surface of the inorganic particles and the silicon, calcium, or aluminum included in the regenerated particles accompanying the crystal growth of the silica sol fine particles. it can. In this case, it is preferable to neutralize by adding an acid to the alkali silicate solution to adjust the pH to a range of about 7-9.

The type of the alkali silicate solution is not particularly limited, but a sodium silicate solution (No. 3 water glass) is particularly desirable from the viewpoint of easy availability. The concentration of the alkali silicate solution is such that the silica component in the regenerated particles is reduced, and the silica content (SiO ₂ equivalent) in the solution is 3% by mass so that silica does not easily precipitate on the surface of the regenerated particles. Preferably, the silica deposited on the surface of the regenerated particles becomes white carbon from the form of the silica sol, and the porosity of the regenerated particles is hindered, and the effect of improving opacity and printability may be insufficient. In order to eliminate this, it is preferable that the silicic acid content is 10% by mass or less.

  Thus, the regenerated particles (C) used in the present invention preferably contain three components of calcium, silicon and aluminum in the particle constituent components. In elemental analysis using an X-ray microanalyzer (model number: E-MAX S-2150, manufactured by Hitachi, Ltd./Horiba, Ltd.), the particle constituents of the regenerated particles include calcium in terms of oxide. Silicon and aluminum are contained in a mass ratio of 30 to 82: 9 to 35: 8 to 35, more preferably 40 to 82: 9 to 30: 9 to 30, particularly 60 to 82: 9 to 20: 9 to 20. It is preferable. The regenerated particles in which the mass ratio of calcium, silicon, and aluminum is adjusted to such a range have a low specific gravity, suppress excessive aqueous solution absorption, and do not have excessive hardness.

  In particular, when the regenerated particles (C) are silica-coated regenerated particles, in the elemental analysis by the X-ray microanalyzer, the particle components of the silica-coated regenerated particles include calcium and silicon in terms of oxides. It is preferable that aluminum is contained in a mass ratio of 30 to 62:29 to 55: 9 to 35. Silica-coated regenerated particles in which the mass ratio of calcium, silicon, and aluminum is adjusted to such a range has a low specific gravity, suppressed excessive aqueous solution absorption, and does not have excessive hardness. Combined with the effect, the occurrence of excessive frictional resistance is suppressed.

  In addition, in the regenerated particles (C) (hereinafter described as a concept including silica-coated regenerated particles), the total content ratio of calcium, silicon and aluminum in terms of oxide is 85% by mass in the particle constituents of the regenerated particles. In addition, the content is preferably 90% by mass or more.

  In order to adjust the mass ratio of calcium, silicon and aluminum in the particle constituents of the regenerated particles (C) within the above range in terms of oxide, it is originally preferable to adjust the raw material composition in the deinking floss. In addition, in the drying process, the combustion process, and, if necessary, in the classification process, it is also possible to adopt a method of containing a coating floss with a clear origin or a preparation process floss by spraying or a method of containing incinerator scrubber lime Is possible.

  For example, a neutral papermaking wastewater sludge or a wastewater sludge from the coated paper manufacturing process is used to adjust calcium in the regenerated particles (C), and a large amount of opacity improver is added to adjust silicon. Paper manufacturing wastewater sludge, papermaking wastewater sludge using acid banding and other sulfuric acid bands for adjusting aluminum, and wastewater sludge from high quality papermaking process with a large amount of clay can be used as appropriate. .

  Further, in the regenerated particles (C), in order to adjust the total content ratio of calcium, silicon, and aluminum to the above range in terms of oxides, for example, a means of using a flocculant that does not contain iron in the flocculation treatment of drainage sludge, Designing or lining the manufacturing equipment process with materials other than iron to prevent iron from entering the system due to wear, etc.Furthermore, high magnetic materials such as magnets are installed in the drying / classifying equipment to reduce the iron content. It is possible to employ a means for removing. In particular, iron is preferably a causative substance that lowers the whiteness by oxidation, and thus is preferably removed selectively.

In addition, for example, the regenerated particles (C) obtained by the production method as described above are used in the differential thermal analysis using the differential thermothermal gravimetric simultaneous measurement device, and the weight loss rate in the decomposition (change to calcium oxide) of calcium carbonate occurring around 700 ° C. By controlling the combustion of the deinking floss so that it becomes 50% or more, the progress of oxidation of the calcium component can be suppressed more accurately, and the regenerated particles (C) can be prevented from becoming hard.

  The regenerated particles (C) thus obtained can easily adjust the volume average particle diameter by appropriately setting the dispersion concentration, temperature and time by wet grinding.

The volume average particle diameter of the regenerated particles (C) is preferably 0.1 to 20 μm, more preferably 5 to 15 μm. When the volume average particle diameter is less than 0.1 μm, the effect of using the regenerated particles (C) as a filler is low, and a multi-color is obtained using a cold set ink at a low basis weight of 36 to 48 g / m ^2. For high-speed offset printing, newsprint paper with excellent printing aptitude is obtained with good offset rotary printing operability, high ink fillability, good ink setting, and improved printing opacity. May be difficult. Conversely, if the volume average particle diameter exceeds 20 μm, the ratio of the regenerated particles (C) having a relatively large particle diameter present on the paper surface increases, which may cause damage to paper powder and printing equipment. .

  Moreover, it is preferable that the particle | grains which have a particle diameter of 5-15 micrometers in regenerated particle | grains (C) are 60% or more of the whole, and also the sharp thing which occupies 62 mass% or more by adjustment of particle formation conditions. . If the particles having a particle diameter of 5 to 15 μm are less than 60% by mass of the whole, the volume distribution of the particles becomes a broad state, so that unevenness of the resulting newspaper paper and unevenness of the paper quality are likely to occur. There is.

  In the present specification, the volume average particle size and volume distribution of the regenerated particles (C) are as follows: a dispersion solution in which 10 mg of a sample is added to 8 mL of a methanol solution and dispersed for 3 minutes with an ultrasonic disperser (output: 80 W). The particle size distribution was measured by a particle size distribution measuring device (laser type microtrack particle size analyzer, manufactured by Nikkiso Co., Ltd.).

  Furthermore, the recycled particles (C) can be added to the raw material pulp in any of the machine chest, fan pump, and suction to the paper machine inlet, but the printing suitability and printing opacity in rotary offset printing are further improved. For this purpose, it is effective to add between the suction and the paper machine inlet, and further before the inlet.

  In the present invention, three kinds of fillers having different shapes and particle diameters, such as white carbon (A), calcium carbonate (B) and regenerated particles (C), are used in combination. Even when the absorption-drying newspaper offset ink vehicle is quickly absorbed and there is no see-through, the speed of the rotary press increases or the amount of printing ink by the double-sided color tower press increases. High absorption drying properties can be exhibited, and the printing opacity and printability can be improved.

  In particular, in the present invention, the deinking of the used paper processing step in which the white carbon (A) is undried white carbon, the calcium carbonate (B) is potato chestnut calcium carbonate, and the recycled particles (C) produce used paper pulp as a papermaking sludge. Using the deinking floss discharged in the process, at least a first combustion process and a second combustion process are performed as a combustion process, and the combustion process is performed at a temperature of 300 ° C. or more and less than 500 ° C. in the first combustion process. It is preferable from the viewpoint of further improving printing opacity and printability.

The blending ratio of the filler is white carbon (A): calcium carbonate (B): regenerated particles (C) = 5-30: 15-70: 20-70 (mass ratio), and further 10-25: 20-65: It is preferable that it is 25-65 (mass ratio) at the point that sufficient absorption drying property is exhibited and the effect of improving printing opacity and printability is large.

  Although the ink setting property is further enhanced by the blending of white carbon (A), if the blending amount of white carbon (A) is too large, ink sinking may occur and the ink density may decrease. is there. Moreover, since white carbon (A) is expensive, it is preferable to reduce the amount of use as much as possible in terms of reduction in production cost. Also from these points, it is preferable to set the blending ratio of white carbon (A), calcium carbonate (B), and regenerated particles (C) within the above range.

The total amount of filler in the raw material pulp is JIS P
It is preferable to adjust it to 7 to 15%, further 8 to 14%, particularly 9 to 13% as measured in accordance with the method described in 8251 “Ashes Test Method”. If the ash content in the newspaper is less than 7%, the full-color ink of each color will be insufficiently set when the newspaper is full-color printed, and problems such as ink back-off and ink rubbing are likely to occur. There is a fear. On the contrary, if the ash content in the newsprint exceeds 15%, a paper breakage trouble is likely to occur in the paper making process, the productivity is lowered, and a problem of contamination in the system may occur. Furthermore, a paper break problem in high-speed rotary printing is likely to occur, which may cause a decrease in printing operability.

  In the present invention, a dispersant may be added in order to improve the dispersibility of the filler with respect to the raw material pulp. There is no particular limitation on the type of the dispersant, and for example, general inorganic filler dispersants such as polyacrylate, polycarboxylate and polyphosphate can be used.

  The amount of the dispersant used is preferably 0.1 to 2 parts by mass, more preferably 0.5 to 1.5 parts by mass with respect to 100 parts by mass of the filler. If the amount of the dispersant used exceeds 2 parts by mass, the dispersion performance may be too good, and it may be difficult to obtain an aggregate that is stable against shear. Conversely, when the amount of the dispersant used is less than 0.1 parts by mass, the slurry viscosity becomes extremely high, which may cause a problem in handling.

  In order to obtain the newsprint of the present invention, a filler is added to the pulp slurry made of the raw material pulp, for example, preferably pH 6 to 10, more preferably pH 6.5 to 9.5 neutral to alkaline. It is possible to adjust the pH and other conditions, and to adopt a method of making paper on a normal paper machine such as a long net paper machine or a twin-wire paper machine. Adding a coagulant in the process, and further adding a flocculant in the pre-stage of the papermaking process following the preparation stage of the raw material pulp promotes the aggregation of fine inorganic particles mixed in the pulp suspension. This is preferable because it has the advantages of adhering inorganic particles to improve the filler yield, improving drainage and obtaining wet-end stability.

  As a coagulant preferably added in the raw material pulp preparation stage as described above, for example, polyacrylamide (PAM), polyvinylamine (PVAm), polydiallyldimethylammonium chloride (polydadomac, PDADMAC), polyamine (PAm), polyethyleneimine Examples thereof include organic polymer coagulants such as (PEI), and inorganic coagulants such as sulfuric acid bands and polyaluminum chloride. Among these, it is preferable to use at least one of PAM, PDADMAC, PAm, and PEI.

The organic polymer-based coagulant retains the regenerated particles (C) among the white carbon (A), calcium carbonate (B), and regenerated particles (C), which are fillers, to improve drainage. From the viewpoint of being able to do so, the charge density is preferably 3 meq / g or more, more preferably 10 meq / g or more. When the charge density is less than 3 meq / g, it is necessary to increase the amount of the organic polymer coagulant to increase the cation requirement of the pulp to a predetermined value. The sheet formation may be reduced. The average molecular weight of the organic polymer coagulant is preferably 700,000 to 1.3 million, more preferably 800,000 to 1,200,000. If the average molecular weight is less than 700,000, the cohesive force is weak, and the filler is not sufficiently fixed on the wet paper. As a result, the intended effect may not be improved. Since the strength is too strong, the amount of newsprint is reduced, and the amount added must be reduced to maintain a good result, and there is a possibility that the intended effect cannot be improved.

  The addition amount of the organic polymer coagulant is preferably adjusted so that the cation requirement reduction rate and the cation requirement of the paper filtrate after the addition of the organic polymer coagulant are satisfied. Therefore, although the addition amount of the organic polymer coagulant depends on the addition amount of the inorganic coagulant described later, it is 1000 to 4000 ppm in solid content with respect to the raw material pulp, and further 1200 to 3800 ppm. preferable. If the amount of the organic polymer-based coagulant added is less than 1000 ppm, the effect may be insufficient. On the other hand, if it exceeds 4000 ppm, the paper texture may be lowered and the cost may be increased.

  Moreover, it is preferable that the addition amount of an inorganic type coagulant is 0.1-5.0 mass% with respect to raw material pulp, Furthermore, it is 0.1-3.0 mass%.

  In addition, when using a cationic coagulant especially among the said coagulants, it is preferable that the addition amount is 50-400 ppm with a pure part with respect to raw material pulp, Furthermore, it is preferable that it is 100-300 ppm. As such a cationic coagulant, a polymer compound similar to the aggregating agent described later, that is, a cationic water-soluble polymer or copolymer, can be used, but those having a small molecular weight are preferably used. That is, as the cationic coagulant, a cationic water-soluble polymer having an average molecular weight of 1,000,000 to 1,200,000 and a ratio of the cationic monomer of 5 to 100 mol%, further 10 to 100 mol%, or Copolymers can be used. Representative examples of such cationic coagulants include PAm, PEI and the like. If the average molecular weight of the cationic coagulant is less than 1 million, the effect of using the cationic coagulant may not be sufficiently exhibited. However, there is a risk of high costs.

  In the present invention, as described above, it is preferable to add a coagulant in the raw pulp preparation stage. For example, the raw pulp and filler, and, if necessary, an internal sizing agent, a fixing agent, and a yield improver. Various papermaking aids such as a cationizing agent, a paper strength enhancer, and an antifoaming agent are mixed in a compounding chest to become a finished raw material. Therefore, it is preferable that a coagulant is added between the compounding chest and the machine chest, and in order to sufficiently mix the coagulant with the finished raw material, it is more preferable to add the coagulant to the compounding chest.

  In particular, when a cationic flocculant is used as the flocculant described later, it is preferable to add the coagulant at an initial stage of raw material pulp preparation, that is, at an early stage with respect to the pulp slurry. After that, it is optimal to add the flocculant before the paper making process, that is, at the head box before the paper making net. When such an addition procedure is adopted, in the slurry solution state before the papermaking raw material is placed on the papermaking net, the cohesive agent has a cohesive effect, which increases the adhesion between the pulp fiber and the filler. In addition, the adhesion between the pulp fiber and the filler becomes stronger. As a result, the yield of the filler in the paper is further improved. And when such an addition procedure is taken, the effect that smooth papermaking work advances with the further improvement of the yield of a filler is also expressed.

  In the present invention, after adding a coagulant in the raw pulp preparation stage, it is preferable to add a flocculant in the first stage of the papermaking process following the raw pulp preparation stage.

  As the flocculant, a cationic flocculant is particularly suitable for an anionic pulp and filler. As such a cationic flocculant, for example, the average molecular weight is 8 million to 12 million, more preferably 8.5 million to 11 million, and the proportion of the cationic monomer is 5 to 100 mol%, further 10 to 100 mol%. Cationic water-soluble polymers or copolymers can be used. Typical examples of such cationic flocculants include PAM. If the average molecular weight of the cationic flocculant is less than 8 million, the effect using the cationic flocculant may not be sufficiently exhibited. On the other hand, if the average molecular weight is larger than 12 million, the desired effect can be hardly improved. However, there is a risk of high costs.

  As described above, the addition of the flocculant is particularly preferably performed in the head stage before the paper making process, that is, in the head box before the paper making net. Thereby, the amount of filler missing in the papermaking net can be significantly reduced.

  Moreover, the addition amount of the flocculant is preferably 100 to 150 ppm, more preferably 120 to 140 ppm as a pure component with respect to the raw material pulp. If the addition amount of the flocculant is less than 100 ppm, the filler yield improvement effect may not be sufficiently obtained, while if it exceeds 150 ppm, the formation of the newsprint may be lowered.

  In the present invention, for example, by using the above-mentioned coagulant or flocculant, the formation index of newsprint can be adjusted to 5 to 10%, further 6 to 9.5%, particularly 7 to 8.5%. preferable. The newsprint of the present invention requires a predetermined tensile strength because it is printed on a rotary press. Therefore, in order to obtain a predetermined tensile strength in the longitudinal direction, the formation index is preferably 5% or more. On the other hand, even if the formation index exceeds 10%, it is difficult to obtain sufficient tensile strength in the vertical direction, and for example, in offset printing, ink absorption unevenness occurs particularly in color printing, resulting in a decrease in printing suitability, particularly printing opacity. There is a risk of being connected.

  In addition, in this specification, the formation index of newsprint means a value measured by a sheet formation tester (manufactured by Toyo Seiki Seisakusho).

  Further, when producing the newsprint of the present invention, before preparing a plurality of stocks and supplying them to a seed box, the slurry of each stock is subjected to a cation demand measurement value measured using an on-line cation demand measurement device. Based on this, the amount of the coagulant added in the preparation stage can be controlled.

  Thus, by controlling the addition amount of the coagulant on-line, it is possible to control the potential according to the optimum cation demand. In particular, it is possible to feed back and control the rapid cation demand measurement value, stabilize the drainage at the wire part of the paper machine, and only reduce the paper breakage at the wet part. In addition, it is possible to satisfactorily maintain the resulting newspaper.

  The cation demand is the total charge of the anionic substance. An anionic substance (anionic trash) is a negatively charged substance, and includes pulp (including fine fibers), filler (white carbon (A), calcium carbonate (B), and regenerated particles (C)). These are various wet end papermaking aids (other fillers, internal sizing agents, antifoaming agents, etc.), resin pitches, elution lignins, and the like.

By adding a cationic coagulant to the anionic substance and adding the anionic (or cationic) flocculant to the coagulated substance, the coagulated anionic substance aggregates to form a floc. Under such a mechanism, the pitch concentration can be reduced mainly by adsorbing the pitch to the pulp and passing the process together with the paper stock in a minimal state, or discharging the process out of the system. Thereby, dirt, a defect, a paper break, etc. can be reduced and productivity can be further improved. Further, the yield can be further improved by neutralization with an anionic substance, and when the anionic substance aggregates and forms a floc, the drainage state is improved. For this reason, it is preferable that the cation demand (or the amount thereof) is low with respect to the drainage state.

  A typical example of an apparatus for measuring an online cation demand as described above is a cation demand measuring apparatus (model number: PCT15 or PCT20, manufactured by Mutek). In the cation demand measuring apparatus, when the stock is introduced into the cell of the tester, the sample liquid flows between the cell cylinder and the piston by the operation of the upper and lower pistons, and electricity is generated by the distortion of the surface charge of the colloidal particles. Arise. The colloidal dissolved substance particles in the pulp suspension are charged with ions, and the charge requirement is measured by measuring the polymer electrolyte by using this.

  Thus, the newsprint of the present invention is obtained through the paper making process. In the present invention, it is preferable that a coating layer containing at least a water-soluble polymer compound is further provided on the front and back surfaces of the newsprint.

  As a result, for example, the vehicle of cold set type offset ink is quickly absorbed, and even if the amount of printing ink is increased by using a high-speed rotary press or using a tower press for double-sided color, sufficient absorption and drying properties are expressed, Furthermore, excellent printing opacity, printability, etc. can be ensured.

The reason why the combination of the filler used in the present invention and the water-soluble polymer compound is suitable is that calcium carbonate (B), especially calcium chloride calcium carbonate, is rich in three-dimensional porosity and has a large specific surface area, For example, it is excellent in the film-forming property at the time of apply | coating an offset ink receiving agent to the newspaper paper surface based on the synergistic effect with water-soluble high molecular compounds, such as starch and / or polyvinyl alcohol (PVA). In particular, Oguri calcium carbonate has a larger oil absorption than normal calcium carbonate, and a basis weight of 36-48 g / m is obtained by quickly absorbing and drying cold-set offset ink on the surface of newsprint paper and combining it with a water-soluble polymer compound. ^{Even if it is 2} and lighter, it exhibits an even better printing opacity improvement effect.

  Suitable water-soluble polymer compounds include, for example, starch and PVA, and these can be used alone or simultaneously.

  The type of starch is not particularly limited. For example, modified starch has an effect of improving tensile strength and surface strength while penetrating into paper, but exhibits neutrality or anionic property, and thus exhibits anionic property. The fixability to the pulp fiber surface is low and the coating property is low. Therefore, in the present invention, it is preferable to use a cationic starch having high fixability to the surface of an anionic pulp fiber. In the case of cationic starch, the fixability to pulp fibers is high, the coating property is excellent, and the surface strength is also improved.

Furthermore, as said starch, esterified starch is more preferable. When esterified starch is used, the ink density and ink setting properties are dramatically improved. Examples of the raw material starch for obtaining such esterified starch include various starch-containing materials in addition to untreated starch and treated starch. Representative examples of such raw material starch include, for example, untreated starch such as wheat starch, potato starch, corn starch, sweet potato starch, tapioca starch, sago starch, rice starch, waxy corn flour, and high amylose content corn starch; And starch-containing materials such as tapioca starch, corn flour, rice flour, etc., and processed starch obtained by subjecting it to oxidation, acid treatment and the like. Among these, tapioca starch is preferable in that the ester-modified product is superior to other cereal starches in terms of viscosity, coating properties, elasticity, and extensibility.

  In the esterified starch, the degree of esterification is not particularly limited, but the average number of ester bonds introduced is preferably 1 to 3, more preferably 1 to 2, per glucose unit. Of the esterified starches, hydroxyesterified starch is preferred. The hydroxyesterified starch can be easily and inexpensively obtained by subjecting the raw material starch to an oxidation treatment and reducing the carboxymethyl group to a hydroxyethyl group. Among them, it is optimal to use a hydrophobic group-containing ester-modified tapioca starch in which a hydrophobic group is introduced into the end group of the ester-modified starch.

  Furthermore, the esterified starch that can be preferably used in the present invention has a carboxylic acid “—COOH” structure in the terminal group and is ionized like “—COO—” in the neutral region to form hydrogen bonds. The ester-modified starch, which exhibits thixotropic behavior based on repulsion without being able to secure the connection due to, shows fluidity when coated on the surface of newsprint paper, but remains in the paper after coating. It is preferable from the viewpoint that it does not easily penetrate into the paper and exhibits high film properties on the paper surface. In particular, when used in combination with PVA or the like having a high coating property, which will be described later, even if calcium carbonate (B), which is a filler added to the raw material pulp, is used in large amounts, especially calcium chloride of chestnut, further improvement in ink concentration and ink setting properties Is planned. As such esterified starch, 1-octenyl succinic esterified starch obtained by ester-modifying tapioca starch as a main raw material is particularly preferable. 1-Octenyl succinate esterified starch is particularly excellent in terms of viscosity, film elasticity, and coatability. For example, when used in combination with PVA described later, printing operability and coatability, ink concentration, and ink setability Can be further improved.

  The starch used in the present invention has an average molecular weight of 600,000 to 3,000,000, more preferably 800,000 to 2.8 million, and the solvent component is paper while keeping the paper surface coverage and the ink component on the paper surface. It is preferable from the point of taking in and improving absorption drying property.

As the starch, those having a viscosity (10%) of 30 × 10 ⁻³ Pa · s or less, more preferably 15 × 10 ^{−3 to} 25 × 10 ⁻³ Pa · s have a high viscosity on the paper surface. From the point that it can not penetrate into the paper and can remain on the paper surface.

  As described above, examples of the water-soluble polymer compound include PVA in addition to starch. In general, when PVA is applied alone to the front and back surfaces of newsprint, the surface strength is approximately three times that of the case where starch is applied alone, and the coating property is high, but the coating property is high. For this reason, when a printing ink that is permeated into a sheet and dried, such as a cold set ink, is used, there is a possibility that the ink absorbability of the printing ink is low and sufficient ink setting properties cannot be obtained. In addition, when a certain amount of PVA is applied alone, the coating agent containing the PVA has a high viscosity. For example, in the film transfer method, paper breakage, papermaking equipment stains, wrinkles, and paper surface stains may occur. . However, when such PVA is used in combination with starch, the coating property for retaining the ink filler component on the paper surface is improved and the ink setting property is lowered while appropriately promoting the penetration of the printing ink solvent into the paper. Is also sufficiently suppressed.

  There is no particular limitation on the type of PVA, and the PVA that can be used in the present invention has a PVA having a terminal cation modified or an anionic group in addition to a normal PVA obtained by hydrolyzing polyvinyl acetate. Modified PVA such as anion-modified PVA is also included.

  As normal PVA obtained by hydrolyzing polyvinyl acetate, those having an average degree of polymerization of 300 to 3000, more preferably 1000 to 2400, and particularly 1700 to 2000 are excellent in compatibility with starch and have a uniform film. It is preferable from the viewpoint of being easily obtained.

  Moreover, as normal PVA, a thing with a saponification degree of 80-100 is preferable, and the complete saponification PVA with a saponification degree of 90-100 is more preferable. When completely saponified PVA is used, a film having water resistance and heat resistance is more easily obtained on the newspaper paper surface than when partially saponified PVA is used.

  When such PVA is used, it has good affinity with starch, can be blended with starch and PVA in a short time, can further improve operability, and reduce the occurrence of mist in the coating equipment. Can be made.

  By using PVA having the above characteristics, it is possible to realize high ink setting properties of offset ink while obtaining a high ink concentration. In addition, when newspaper sheets are stacked after printing, ink transfer to the back surface can be sufficiently prevented.

  When starch and PVA are used in combination, the ratio of the two (starch: PVA (solid content mass ratio)) is 10: 0.8 to 10: 2, and further 10: 0.9 to 10: 1.2. It is preferable. When the ratio of PVA to starch exceeds 10: 2, the viscosity of the coating agent containing both increases rapidly, resulting in coating unevenness and mist, resulting in poor coating quality and contamination around the equipment. On the other hand, if the ratio is less than 10: 0.8, there is no problem with the compatibility between starch and PVA, but when applied to the newspaper surface, the synergistic effect between starch and PVA cannot be obtained. There is a risk of penetration into the paper and uneven coating. Therefore, by setting the ratio of both in this range, a synergistic effect between starch and PVA can be ensured, and at the same time a high ink concentration is expressed by retaining the filler component in the ink on the newspaper surface, It is possible to quickly absorb the solvent in the ink into the newspaper, and to express the ink setting property quickly.

When a coating agent containing at least a water-soluble polymer compound is applied to the front and back surfaces of newsprint, the amount of the water-soluble polymer compound per side is 0.2 to ² g / m ² in terms of solid content, It is preferable to adjust so that it may become 0.5-1.5 g / m < ² >. When the amount of the water-soluble polymer compound is less than 0.2 g / m ² , it becomes difficult to obtain sufficient film properties with the water-soluble polymer compound, and the filler component in the ink is difficult to stay on the surface of the newsprint. There is a possibility that a high ink density may not be obtained. On the other hand, if it exceeds ² g / m ² , a large amount of coating agent mist containing a water-soluble polymer compound is generated around the coating equipment, and the peripheral equipment is soiled. There is a risk of paper breakage and paper defects due to dirt.

  When a coating agent containing a water-soluble polymer compound such as starch or PVA is applied to the front and back surfaces of newsprint, it is preferable to employ a film transfer system such as a gate roll coater or a blade. In particular, coating with a gate roll coater, unlike other coating methods, is most suitable for applying contour coating with high coverage on the surface of newsprint paper with a low coating amount. Since no shear force is applied, the coating agent used in circulation is excellent in stability, and a uniform film can be obtained at high speed. In particular, when thixotropic ester-modified starch is used, fluidity is suppressed when coated on the surface of newspaper paper, but fluidity is suppressed after coating, and the coating agent is difficult to penetrate into the paper. The high film property is imparted to the newsprint while staying on the paper surface.

In addition, when applying a coating agent mainly composed of starch and PVA as a water-soluble polymer compound on the front and back surfaces of newspaper paper, for example, a size press or a rod metalling, without adopting the film transfer method. It is also possible to employ a conventionally known coating means such as a size press. However, if the contour coating along the unevenness of the newsprint paper surface is not applied, the coverage with starch and PVA becomes insufficient. For example, when multicolor offset rotary printing is performed using cold set ink, the ink concentration, There is a risk that it is difficult to obtain newsprint paper that is sufficiently excellent in printability such as ink setting properties and ink fillability. Therefore, it is optimal to adopt the film transfer method in order to apply the coating agent mainly composed of starch and PVA on the front and back of the newspaper with a low concentration and a low coating amount.

The newsprint of the present invention thus obtained has a basis weight of 36 to 48 g / m ² measured according to the method described in JIS P 8124 “Paper and Paperboard—Basis Weight Measurement Method”. When the basis weight is less than 36 g / m ² , the opacity and paper quality strength are insufficient, and in high-speed printing in recent years, which reaches 170 to 200,000 copies / hour, there is a problem that paper breakage easily occurs. . On the other hand, when the basis weight exceeds 48 g / m ² , it is possible to ensure opacity without using the construction of the newsprint of the present invention, and it is contrary to the recent weight reduction of newsprint.

  Further, the newsprint of the present invention has a blank paper opacity of 90% or more, preferably 90.5, measured according to the method described in JIS P 8149 “Paper and paperboard—Opacity test method (paper backing)”. % Or more. When the blank paper opacity is less than 90%, not only the appearance of the blank paper before printing is deteriorated but also the appearance of the printed matter after the offset printing is lowered.

  Furthermore, the newsprint of the present invention has a printing opacity of 85% or more, preferably 90% or more. When the printing opacity is less than 85%, not only the appearance of the printed matter after the offset printing is deteriorated but also the showthrough occurs.

  In this specification, the printing opacity of newsprint is the offset rotary printing press (model number: RI-2 type, manufactured by Ishikawajima Industrial Machinery Co., Ltd.) The ratio of the backside reflectance after printing to the backside reflectance before printing when the ink amount of squirrel (black), manufactured by Dainippon Ink & Chemicals, Inc. is changed and the printed surface reflectance is 9%. : (Back surface reflectance after printing / back surface reflectance before printing) × 100 (%) (measurement of reflectance: spectral whiteness colorimeter (manufactured by Suga Test Instruments Co., Ltd.)) Say.

  Next, the newspaper of the present invention will be described in more detail based on the following examples, but the present invention is not limited to these examples.

Preparation examples 1 to 4 (production of regenerated particles)
Using deinking floss (deinking floss discharged from the flotation process of the used paper processing process for producing deinked waste paper pulp) as a raw material, dehydration under the conditions shown in Tables 1-2 according to the manufacturing equipment flow shown in FIG. The process, the first combustion process (drying / combustion process) and the second combustion process are sequentially performed, and after the particles are agglomerated in the second combustion process, a wet pulverization process is performed in the pulverization process. Obtained.

  In Preparation Examples 1 to 4, in the first combustion process, an internal heat kiln furnace (shown as internal heat kiln in Table 1) using a heavy oil / gas mixed combustion burner in which the main body is placed horizontally and rotates around the central axis is used. In the second combustion step, an externally heated electric kiln furnace (shown as an externally heated kiln in Table 2) was used.

  In Preparation Example 4, after the regenerated particles were added to and dispersed in a sodium silicate solution (water glass) to prepare a slurry, the liquid temperature was maintained at 90 ° C. while heating and stirring, and dilute sulfuric acid was added. A silica sol was produced. Next, the pH of the final reaction solution was adjusted to 9, and silica was deposited on the surface of the regenerated particles to obtain silica-coated regenerated particles.

  About the obtained regenerated particles (and silica-coated regenerated particles), the content of calcium, silicon and aluminum in the particle constituents (as oxide), the total content of calcium, silicon and aluminum (as oxide), volume The average particle size, appearance, wire wear degree, productivity and quality stability were investigated. These results are shown in Tables 3-4.

  In addition, the various measured values shown to Tables 1-4 were measured with the following method.

(A) Moisture content of dehydrated material A sample was collected and measured in accordance with the method described in JIS P 8127 “Paper and paperboard—Moisture test method—Method using a dryer”.

(A) Average particle size and particle distribution of dehydrated product Measure the average particle size with a metal plate sieve specified in JIS Z8801-2 (2000) “Sieving for test-Part 2: Metal plate sieve”. The ratio of particles having a particle diameter of 50 mm or less was calculated.

(C) Oxygen concentration in the upper end of the first combustion furnace and in the vicinity of the burner of the second combustion furnace This was measured with a gas analyzer (model number: PG250 type, manufactured by Horiba, Ltd.).

(D) Unburnt rate of combusted material after the first combustion process After heating the electric muffle furnace to 600 ° C in advance, put the sample in a crucible and burn it completely in about 3 hours. Was calculated.

(E) Content of calcium, silicon and aluminum in regenerated particles (as oxide)
Elemental analysis of particle constituents was performed with an X-ray microanalyzer (model number: E-MAX S-2150, Hitachi, Ltd./Horiba, Ltd.). Further, the total content ratio (calculated in terms of oxide) of calcium, silicon and aluminum in the particle constituents of the regenerated particles was calculated from the contents of these calcium, silicon and aluminum.

(F) Volume average particle size and particle distribution of regenerated particles A particle size distribution measuring device for a dispersion solution obtained by adding 10 mg of a sample of regenerated particles to 8 mL of methanol solution and dispersing for 3 minutes with an ultrasonic disperser (output: 80 W). (A laser type microtrack particle size analyzer, manufactured by Nikkiso Co., Ltd.) was used to measure the volume average particle size and the proportion of particles having a particle size of 5 to 15 μm.

(G) Appearance The color of the regenerated particles was visually observed and divided into white and gray.

(H) Degree of wire wear Using a wear degree test apparatus (manufactured by Nippon Filcon Co., Ltd.), the degree of wear of the plastic wire was measured for 3 hours at a slurry concentration of 2% by mass.

(I) Productivity Each of the raw material dehydration efficiency, productivity, and electric power required for pulverization was evaluated in five stages, and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: All were highly evaluated and the balance was the best.
○: The evaluation may be averaged.
(Triangle | delta): There existed a problem in either the dehydration efficiency, productivity, and the electric power required for a grinding | pulverization.
X: Actual operation was difficult.

(G) Quality stability The degree of variation was measured for each item of whiteness, particle diameter, and production volume at a fixed time interval, and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: No change was found in any item.
○: There was almost no change in any of the items.
Δ: Variation was observed in any of the items.
X: Variation was observed in all items.

  From the results shown in Table 4, it can be seen that all the regenerated particles of Preparation Examples 1 to 4 have high whiteness, low wire wear, and excellent productivity and quality stability. In particular, as in Preparation Examples 2 to 4, the regenerated particles obtained by the combustion treatment at a temperature of 300 ° C. or higher and lower than 500 ° C. in the first combustion step have a lower wire wear degree and are more excellent. Recognize.

Examples 1-13 and Comparative Examples 1-7
Deinked waste paper pulp (shown as DIP in Table 5) and thermomechanical pulp (shown as TMP in Table 5) produced from newspaper waste paper were mixed at the ratio shown in Table 3 to obtain raw pulp. To this raw material pulp, white carbon (A), calcium carbonate (B), and regenerated particles (C) are added as fillers at the ratios and addition locations shown in Tables 5 to 7, and further the coagulant shown in Table 8 is added. A pulp slurry was obtained.

In addition, the filler shown in Tables 5-7 is as follows.
Undried: Undried white carbon Dried: dried white carbon Chestnut: Chestnut calcium carbonate Heavy: Heavy calcium carbonate Spindle type: Spindle type calcium carbonate

  Moreover, the various measured values shown to Tables 5-6 were measured with the following method.

(I) Volume average particle diameter of white carbon A particle size distribution measuring apparatus (laser method) was used for a dispersion solution in which 10 mg of white carbon sample was added to 8 mL of methanol solution and dispersed for 3 minutes with an ultrasonic disperser (output: 80 W). No. Microtrack particle size analyzer, manufactured by Nikkiso Co., Ltd.).

(Ii) Oil absorption amount of calcium carbonate Measured according to the method described in JIS K 5101-13-1 “Pigment test method—Part 13: Oil absorption amount—Section 1: Purified linseed oil method”.

(Iii) BET specific surface area of calcium carbonate Measured with a fully automatic BET specific surface area measuring device (model number: Frosorb 2300, manufactured by Shimadzu Corporation).

(Iv) Volume average particle size of calcium carbonate A 10 mg sample of calcium carbonate was added to 8 mL of methanol solution and dispersed for 3 minutes with an ultrasonic disperser (output: 80 W). No. Microtrack particle size analyzer, manufactured by Nikkiso Co., Ltd.).

  Next, the flocculant shown in Table 8 was added to the obtained pulp slurry, and paper was made with a long net paper machine at a paper making pH of about 6.5 to produce a base paper.

In addition, the coagulant | flocculant and flocculant which are shown in Table 8 are as follows, and the addition amount is the quantity with respect to raw material pulp.
PEI: Polyethyleneimine PAM: Polyacrylamide

  Next, on the front and back surfaces of the obtained base paper, the water-soluble polymer compound shown in Table 9 and water are mixed with stirring, and the coating liquid whose solid content concentration is adjusted to 1 to 20% by mass is shown in Table 10. With the coating method shown, the coating was carried out so that the amount of the water-soluble polymer compound per side was the value shown in Table 10 in terms of solid content, and newsprint paper was obtained.

In addition, the water-soluble polymer compounds shown in Table 9 are as follows.
Esterified starch: 1-octenyl succinate esterified starch

  Each physical property of the obtained newspaper was measured by the following method. These results are shown in Table 11.

(A) Basis weight It measured based on the method of JISP8124 "basis weight measuring method".

(B) Paper surface pH
Using a pH measurement kit for paper (manufactured by Kyoritsu Riken), a reagent (MPC-BCP, pH 4.8 to 6.8) was used, and it was visually measured with a discoloration standard meter.

(C) Ash content in paper Measured according to the method described in JIS P 8251 “Paper, paperboard and pulp-ash content test method—525 ° C. combustion method”.

(D) Formation index Measured with a sheet formation tester (manufactured by Toyo Seiki Seisakusho).

(E) Whiteness Measured according to the method described in JIS P 8148 (2001) “Paper, paperboard and pulp—Measurement method of ISO whiteness (diffuse blue light reflectance)”.

(F) White paper opacity It was measured according to the method described in JIS P 8149 (2000) “Paper and paperboard—Opacity test method (backing of paper)”.

(G) Printing Opacity Offset rotary printing press (model: RI-2, manufactured by Ishikawajima Industrial Machinery Co., Ltd.), offset rotary printing ink (trade name: News Zet Naturalis (black), Dainippon Ink & Chemicals, Inc. The ratio of the back-surface reflectance after printing to the back-surface reflectance before printing when the amount of ink is 9% and the printing surface reflectance is 9%.
(Back side reflectance after printing / Back side reflectance before printing) × 100 (%)
Asked. A spectral whiteness colorimeter (manufactured by Suga Test Instruments Co., Ltd.) was used for measuring the reflectance.

(H) Opacity difference The difference (absolute value) between blank paper opacity and printing opacity was determined.

(I) Ink concentration Using an RI printing aptitude tester (model number: RI-2 type, manufactured by Ishikawajima Industrial Machinery Co., Ltd.), the paper was passed through the gap between the metal roll and the rubber roll at a speed of 30 rpm, and offset printing ink ( Product name: News Zeta Naturalis (black), manufactured by Dainippon Ink & Chemicals, Inc., ink usage: 0.85 mL) (test piece: CD direction 50 mm, MD direction 100 mm). Print samples up to 3 printings were dried for 24 hours in a constant chamber condition (according to JIS P 8111 “Paper, paperboard and pulp—standard conditions for humidity conditioning and testing”). With respect to the samples printed once, twice, and three times, the ink density at 10 randomly selected printing sites was measured with a Macbeth densitometer, and the average value thereof was obtained.

(J) Area ratio About the printing surface of the obtained newspaper paper, the area of a fixed area is 12000 times using the X-ray microanalyzer (model number: E-MAX, manufactured by Horiba, Ltd.) attached to the scanning electron microscope. In 25 different parts of the sample, a mapping photo image was obtained by elemental analysis in terms of oxides of calcium, silicon and aluminum using the X-ray microanalyzer, and the image was analyzed on an image analyzer (model number: Luzex, manufactured by Nireco Corporation). Then, the area detected by overlapping calcium, silicon and aluminum is measured as the area (C) of the area where the regenerated particles are present, and the area of silicon alone is the area (A) where the white carbon is present. The area detected independently is calculated as the area (B) of the area where calcium carbonate is present. In addition, (A), (B), and (C) the existence ratio in the total measurement area area of the total area area was defined as the area ratio.

  Next, each characteristic was investigated about the obtained newsprint based on the following test examples 1-5. The results are shown in Table 12.

Test Example 1 (Ink setting property)
Using an RI printing aptitude tester (model number: RI-2 type, manufactured by Ishikawajima Industrial Machinery Co., Ltd.), newspaper ink (trade name: Newsjet Naturalis (indigo), manufactured by Dainippon Ink & Chemicals, Inc.) After solid printing with, the coated paper was stacked on the printing surface and pressure-bonded at a constant pressure. The state of ink transfer to the coated paper was visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
(Double-circle): The stain | pollution | contamination does not arise at all on the coated paper surface.
○: Slight dirt is generated on a part of the coated paper surface, but there is no practical problem.
Δ: Stain is observed on the entire coated paper surface.
X: Stain on the entire coated paper surface is remarkable.
Of the above evaluation criteria, the cases of ○ and ○ are judged to be actually usable.

Test example 2 (ink inking property)
Using an offset printing press (model number: Komori SYSTEMC-20, manufactured by Komori Corporation), using a color ink for newspapers (trade name: News Webmaster Eco Pure, manufactured by Sakata Inks Co., Ltd.), continuous 10,000 copies of 4 colors Printing was done. About the obtained printed matter, the clearness and the shading unevenness of an image were observed visually, and it evaluated based on the following evaluation criteria.
(Evaluation criteria)
(Double-circle): The image is clear, there is no unevenness in density, and the ink deposition property is excellent.
A: The image is clear, there is almost no unevenness in density, and the ink deposition property is good.
Δ: There are portions where the image is unclear and unevenness in density, and ink inking properties are not good.
X: Overall, the image is unclear, the density unevenness is remarkable, and the ink deposition property is inferior.
Of the above evaluation criteria, the cases of ○ and ○ are judged to be actually usable.

Test example 3 (surface strength)
In accordance with the method described in JIS K 5701-1, “Lithographic Ink—Part 1: Test Method”, using a color change tester (model number: RI-1 type, manufactured by Ishikawajima Industrial Machinery Co., Ltd.) Printing was performed under the condition of 18 single printings. The newspaper paper surface was visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: The entire surface of the newsprint is not removed.
○: Slightly removed on a part of the newspaper surface, but there is no practical problem.
Δ: Taken over the entire newspaper surface.
X: Significant removal on the entire newspaper surface.
Of the above evaluation criteria, the cases of ○ and ○ are judged to be actually usable.

Test Example 4 (Ink absorption unevenness)
Using an offset printing machine (model number: Komori SYSTEMC-20, manufactured by Komori Corporation), four-color printing was performed using newspaper color ink (trade name: News Webmaster Eco Pure, manufactured by Sakata Inx Corporation). . About the obtained printed matter, the ink density unevenness of the indigo / red heavy color portion was visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: There is no unevenness in the ink density, and the image is uniform and clear.
◯: There is almost no ink density unevenness and the image is uniform.
(Triangle | delta): The ink density nonuniformity is recognized in part, and there exists a location where an image is unclear.
X: Overall, the ink density unevenness is remarkable and the image is unclear.
Of the above evaluation criteria, the cases of ○ and ○ are judged to be actually usable.

Test Example 5 (printing operability)
(1) Cutter tip clogging Using an offset rotary printing press (model number: LITOPOPIA BTO-N4, manufactured by Mitsubishi Heavy Industries, Ltd.), printing was performed on 50-roll newspapers. The presence or absence of clogging of the sword tip was examined and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: No sword clogging occurred.
○: A sword clog occurred only once with one winding.
Δ: Claw tip clogging occurred 2 to 3 times with one winding.
X: Sword tip clogging occurred 4 times or more with one winding.
Of the above evaluation criteria, the cases of ○ and ○ are judged to be actually usable.

(2) Blanket paper powder piling Using an offset printing machine (model number: Komori SYSTEMC-20, manufactured by Komori Corporation), continuous 4-color 4-color printing was performed. The presence or absence of paper dust generation / deposition in the blanket non-image area was visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
(Double-circle): Generation | occurrence | production of paper dust is not recognized at all.
○: Slight generation of paper dust is observed, but no deposition on the blanket is observed.
(Triangle | delta): Generation | occurrence | production of paper dust is recognized and it has accumulated on the blanket.
X: Accumulation of paper dust on the blanket is remarkable.
Of the above evaluation criteria, the cases of ○ and ○ are judged to be actually usable.

(3) Neppari (Blanket adhesive)
Two samples obtained by cutting newspaper paper into a size of about 4 cm in width and about 6 cm in length were prepared, immersed in water for 10 seconds, and then these two samples were quickly brought into close contact with each other. This was passed through a calendar at a linear pressure of 100 kg / cm, dried at room temperature for 24 hours, and then manually peeled off two samples (T peel peel test imitation sensory test). Based on the evaluation.
(Evaluation criteria)
(Double-circle): It did not peel and it did not adhere | attach at all.
○: Although partly adhered, it could be easily peeled off.
(Triangle | delta): There existed a part which has adhere | attached and was hard to peel.
X: Adhered as a whole, and fluffing of fibers from the adhesion surface was observed at the time of peeling.
Of the above evaluation criteria, the cases of ○ and ○ are judged to be actually usable.

As shown in Tables 11 to 12, all the newspapers of Examples 1 to 13 were internally added to the raw pulp by combining white carbon (A), calcium carbonate (B) and regenerated particles (C) as fillers. Thus, while the basis weight is as light as about 36 to 46 g / m ² , the whiteness and white paper opacity are high, and high printing opacity is maintained. Moreover, each of the newspapers of Examples 1 to 13 not only has a moderately high ink concentration of about 1.2 to 1.4, but also has good ink setting properties and ink fillability and excellent printability. Furthermore, it has a high surface strength and excellent printing operability, and has excellent characteristics particularly suitable for high-speed multicolor rotary printing.

  On the other hand, the newspapers of Comparative Examples 1 to 7 are particularly free of white paper opacity because at least one of white carbon (A), calcium carbonate (B) and regenerated particles (C) is not internally added as a filler. Low and printing opacity is also relatively low. Moreover, since all the newspapers of Comparative Examples 1 to 7 have low ink setting properties and poor ink applicability, poor printability, low surface strength, and poor printing operability, for example, high-speed multicolor offset rotary printing. It does not have the necessary characteristics.

  The newsprint of the present invention can be suitably used for offset printing such as high-speed multicolor offset rotary printing using a cold set type ink, for example.

10 Raw material 14 First combustion furnace 32 Second combustion furnace

Claims (5)

Newspaper paper comprising at least constituents of raw pulp containing filler pulp as a main component and filler,
As filler, it contains white carbon (A), calcium carbonate (B) and regenerated particles (C),
Recycled particles (C) are inorganic particles obtained using papermaking sludge as the main raw material, and through a dehydration step, a drying step, a combustion step, and a pulverization step,
The basis weight measured in accordance with JIS P 8124 is 36 to 48 g / m ² , the blank paper opacity measured in accordance with JIS P 8149 is 90% or more, and the printing opacity is 85% or more. And newspaper. White carbon (A) is undried white carbon,
Calcium carbonate (B) is Oguri calcium carbonate,
The regenerated particles (C) use deinking floss discharged in the deinking process of the used paper processing process for producing used paper pulp as papermaking sludge, and at least the first combustion process and the second combustion process are performed as the combustion process, The newsprint according to claim 1, wherein the newspaper is regenerated particles obtained by combustion treatment at a temperature of 300 ° C or higher and lower than 500 ° C in the first combustion step.   The blending ratio of the filler is white carbon (A): calcium carbonate (B): regenerated particles (C) = 5-30: 15-70: 20-70 (mass ratio) according to claim 1 or 2. Newspaper.   The newsprint according to claim 1, 2 or 3, wherein a coating layer containing at least a water-soluble polymer compound is provided on the front and back surfaces. The newsprint according to claim 4, wherein the amount of the water-soluble polymer compound per side is 0.2 to ² g / m ² in terms of solid content.

Images