JP5192191B2 - Newspaper - Google Patents

Description

  The present invention relates to newsprint. More specifically, for example, even when the proportion of waste paper pulp is high, it is bulky and has a low basis weight, so it has excellent printing opacity and printability, and is particularly suitable for high-speed offset printing. Regarding newsprint.

  Conventionally, from the viewpoint of protecting wood resources, it has been directed to use waste paper as a pulp raw material for general printing paper. Newspaper paper is an excellent student of recycling, and although it is a paper having a relatively high ratio of wastepaper pulp, efforts are being made to further increase the ratio of wastepaper pulp.

  In recent years, with the increase in the amount of waste paper pulp corresponding to such environmental protection, the newspaper paper is cold set type at a speed of 170,000 to 200,000 copies per hour as the paper weight corresponding to the increase in the number of pages progresses. Printing is performed by offset rotary printing using ink, and it is required to satisfy printability that can withstand such high-speed rotary printing.

  Newspaper paper that satisfies the printability that can withstand the increase in page weight and high-speed rotary printing, for example, contains 50% or more of mechanical pulp and / or deinked waste paper pulp, and is a water-soluble polyvalent metal salt Inkjet recording paper for newspaper printing (see Patent Document 1) for recording using a pigment ink containing at least a colorant pigment and water, and pulp slurry mainly composed of deinked waste paper pulp and mechanical pulp There has been proposed a neutral newspaper (see Patent Document 2) and the like in which a predetermined amount of calcium carbonate is contained and an organic film is formed on the surface of calcium carbonate particles in the pulp slurry.

  However, newsprint is primarily made from newspaper waste paper that has been recycled repeatedly, so that waste paper pulp made from newsprint paper becomes brittle as the waste paper pulp obtained becomes brittle through repeated recycling. There are fewer fibrils needed to entangle each other, and there is a problem that sufficient bulk cannot be obtained, and the amount of coated paper such as mixed leaflets tends to increase, leading to raw pulp derived from coated paper There is a problem that an adhesive foreign matter that causes an increase in carry-in ash content and a paper break due to synthetic resins (for example, latex) is likely to occur. Further, when the blending amount of the filler is increased in order to suppress the decrease in opacity associated with the weight reduction of the paper as described above, or when the amount of paper ash derived from the used paper is increased, there is a problem that the bulk is lowered.

  On the other hand, in recent years, efforts have been made to deal with environmental problems, and the system for collecting used paper, which is the raw material of used paper pulp, has been arranged, and various types of used paper are being sorted according to the raw material composition. Because of this, it was difficult to obtain used paper with a constant quality, and the used paper was blended so that a used paper pulp of a constant quality was obtained at the disintegration stage of the used paper. It can be used stably and can be used as a raw material for newsprint.

  Recycled paper, in particular, has a high mixing rate of mechanical pulp, unlike traditionally used newspaper wastepaper. For example, it is possible not only to use a large amount of waste paper of approximately the same quality as residual wastepaper, The amount of coated papers such as leaflets that are mixed in much is extremely small, and there is no problem of carry-in ash or problems caused by synthetic resin beyond the coated paper office. Furthermore, since there is no risk of light foreign matter such as whisker-like objects caused by the string that binds used paper, which is a problem in the use of used newspaper, paper breakage hardly occurs, and it has attracted attention as a very good used paper material in newsprint. ing.

However, while it is possible to obtain bulky and highly opaque newsprint paper from recycled paper pulp made from recycled paper having the advantages described above, the recycled paper is made of hot melt or the like. Because it contains glue and contains a lot of rigid mechanical pulp, it tries to obtain paper quality that can satisfy recent demands as newspaper, such as being lightweight and having printability that can withstand high-speed rotary printing. Then, following the conventional waste paper processing method, there still occurs a problem that the bulk does not appear and the printability is poor.
JP 2003-326844 A Japanese Patent Application Laid-Open No. 2006-124885

  The present invention has been made in view of the above-described background art, for example, even when the blending ratio of waste paper pulp is high, bulky, and low basis weight, printing opacity and printability. An object of the present invention is to provide newsprint paper that is excellent in printing and particularly suitable for high-speed offset printing.

The present invention
Newspaper paper in which a coating liquid is coated on the surface of a base paper comprising at least constituent pulp containing waste paper pulp and filler,
Waste paper pulp derived from used paper is used as the waste paper pulp, and the content ratio of mechanical pulp in all raw materials of the base paper is 50% by mass or more,
The filler contains regenerated particle aggregates mainly composed of calcium chestnut calcium carbonate and deinked floss,
A water-soluble polymer compound is contained in the coating liquid, and the water-soluble polymer compound is contained in a solid content of 0.2 to 5.0 g / m ² on the paper surface.
In accordance with the method described in ISO 8791-4, using a soft rubber packing disk, the Parker Print Surf surface roughness of the paper surface measured under the condition of a clamp pressure of 1 MPa is 4.0 to 5.5 μm,
Using a specular reflection type smoothness meter, the specular reflection type smoothness of the paper surface measured under the conditions of 20 kg / cm ² pressure, light wavelength of 0.5 μm and measurement time of 100 MS is 9 to 14%. It relates to newspaper.

According to the present invention, for example, even when the blending ratio of waste paper pulp is high, it is bulky enough to satisfy recent requirements, and even if it has a low basis weight such as 35 to 50 g / m ² , printing is not possible. Newspapers that are excellent in printability, such as high transparency, ink concentration, ink setability, ink fillability, etc., and no unevenness in ink absorption, are particularly suitable for high-speed offset printing.

(Embodiment)
The newsprint of the present invention is obtained by applying a coating liquid on the surface of a base paper comprising at least constituent pulp containing waste paper pulp and a filler, and the waste paper pulp is a waste paper pulp derived from recycled paper. (Hereinafter referred to as “recycled paper pulp”), the content ratio of mechanical pulp in all raw materials of the base paper is 50% by mass or more, and the coating liquid contains a water-soluble polymer compound, A specific amount of water-soluble polymer compound is contained on the paper surface.

  First, the pulp used in the present invention will be described. The pulp constituting the base paper of the newsprint of the present invention includes waste paper pulp, and the waste paper pulp includes renewed paper pulp.

  It is preferable from the viewpoint of environmental protection to mix recycled paper pulp in this way, and in recent years, especially from the viewpoint of effective use of resources, utilization of recycled paper pulp and higher blending have been demanded. On the other hand, when the proportion of waste paper pulp increases, especially when waste paper pulp derived from newspaper waste paper is used frequently as a raw material for newsprint paper, as described above, waste paper pulp derived from newspaper paper that has been reused several times is used. It is brittle and deteriorated, and there are few fibrils necessary for the entanglement of pulp fibers, and it is difficult to obtain sufficient quality.

  In particular, among waste paper pulp, when using waste paper pulp derived from newsprint, there is a risk of light foreign matter such as whiskers and the like being likely to break, so when using high-speed web offset printing in recent years, the operability is reduced. Immediate improvement is necessary to invite.

However, in the present invention, as will be described later, a water-soluble polymer compound is contained in the coating liquid applied to the base paper surface, the water-soluble polymer compound is contained in a predetermined amount on the paper surface, and ISO 8791- 4, the Parker print surf surface roughness of the paper surface measured using a soft rubber packing disk under the condition of a clamp pressure of 1 MPa is 4.0 to 5.5 μm, and is a regular reflection type Since the regular reflection type smoothness of the paper surface measured using a smoothness meter under the pressure of 20 kg / cm ² , light wavelength of 0.5 μm, and measurement time of 100 MS is 9 to 14%, reprint on the base paper Despite the fact that waste paper pulp is contained, it contains 20% by weight or more of the total amount of pulp, preferably 25 to 100% by weight, more preferably 30 to 100% by weight. In case Even so, the newsprint of the present invention is bulky and has high printing opacity while ensuring printability.

  The used paper pulp used in the present invention is mainly made from used paper. In addition, in this specification, in the conventional used paper classification, in the conventional used paper classification, the number 6012 “printing paper D” described in JIS P 0001 “Paper / Paperboard and Pulp Term” (definition: containing chemical pulp of less than 40%) Non-coated printing paper) or used paper that is included in the classification of “middle white”, “separate top cut”, etc. described in the “Recycled Paper Standard Quality Standards Table” by the Recycled Paper Recycling Promotion Center. As used waste paper, it is collected and recycled as a stable waste paper raw material without any mixing with other waste paper from publishers, etc. Unlike newspaper waste paper, it has a high mechanical pulp contamination rate and low ash content. In addition, the amount of coated paper such as leaflets mixed in old newspaper is extremely small, and there is also a feature that there is little mixing of whiskers that cause paper breaks.

The newsprint of the present invention using recycled paper pulp as a raw material is in accordance with the method described in ISO 8791-4 “Paper and paperboard—Roughness / Smoothness Test Method (Air Leakage Method) —Part 4: Print Surf Method”. In conformity, the Parker Print Surf surface roughness (hereinafter referred to as PPS) of the paper surface measured under the condition of a clamping pressure of 1 MPa using a soft rubber packing disk is 4.0 μm or more, preferably 4.1 μm or more. The surface of the paper was measured to be 5 μm or less, preferably 5.4 μm or less, and using a specular reflection type smoothness meter under a pressure of 20 kg / cm ² and a light wavelength of 0.5 μm and a measurement time of 100 MS. It is preferable that the regular reflection type smoothness is 9% or more, preferably 9.5% or more, and 14% or less, preferably 13.5% or less.

  Both PPS and specular reflection type smoothness are indicators for numerically evaluating the surface properties of newsprint, but as in the present invention, mechanical pulp is highly blended to evaluate the flatness of bulky newsprint. PPS that can evaluate the flatness in the microscopic area equivalent to the halftone dots and the regular reflection type smoothness considering the cushioning property due to the bulkiness of the paper surface in a relatively wide range in the evaluation of printability on the newspaper surface It is necessary to satisfy both evaluation values.

  Conventionally, as a method for adjusting PPS and regular reflection type smoothness, for example, a method of physically flattening the surface of newsprint paper using, for example, a soft calendar, a super calendar, or a machine calendar, or a ratio of a filler to be included in the paper However, since both methods result in physical treatment of the paper surface, even if they are used alone or in combination, sufficient flatness is maintained while maintaining bulkiness. Is difficult to obtain, and in recent years the basis weight has been reduced.

  However, the present inventors do not perform a physical treatment on the conventional paper surface, but perform a disaggregation treatment and a beating treatment on the raw material pulp under the conditions described later. It has been found that it is preferable to ensure the flatness and bulkiness of the film at the same time.

PPS is to measure the unevenness (flatness) of the paper surface in a region separated by a narrow interval of about 50 μm. On the other hand, specular reflection type smoothness is relatively measured at a constant pressure and at a measurement time. The flatness of the paper surface is measured by the amount of optical reflection over a wide range of paper surfaces. Therefore, it is useful as an index for evaluating and adjusting the surface properties of newsprint paper, which is a relatively stiff, used paper pulp derived from recycled paper that uses a lot of mechanical pulp. The surface roughness (hereinafter referred to as PPS) is 4.0 μm or more, preferably 4.1 μm or more, 5.5 μm or less, preferably 5.4 μm or less, and using a regular reflection type smoothness meter, The regular reflection type smoothness of the paper surface measured at 20 kg / cm ² under the conditions of a light wavelength of 0.5 μm and a measurement time of 100 MS is 9% or more, preferably 9.5% or more, preferably 14% or less, preferably By producing newsprint so that it becomes 13.5% or less, it is possible to print in fine print even when using waste paper pulp derived from recycled paper, while ensuring the appearance of photographs and design parts, At a rate of 17 to 200,000 parts per hour, in order to identify the quality capable of satisfying the printability capable of withstanding high-speed web offset printing using cold-set type ink, it is possible to satisfy both.

  PPS and specular reflection type smoothness are the disaggregation process in the used paper pulping process of the used paper, for example, the beating process such as viscous beating, and the composition of the coating liquid applied to the surface of the base paper (for example, a water-soluble polymer compound). ), The coating amount, the type of filler to be internally added, the addition amount, and the like can be adjusted at any time by singly or in combination.

  When the PPS is less than 4.0 μm, there is a problem that it is difficult to produce bulk and inferior in opacity. Conversely, if the PPS exceeds 5.5 μm, there arises a problem that the ink setting property is deteriorated.

  On the other hand, when the regular reflection type smoothness is less than 9%, there arises a problem that the printability is inferior, such as a decrease in ink deposition property and occurrence of ink absorption unevenness. On the other hand, when the regular reflection type smoothness exceeds 14%, there arises a problem that the ink setting property is deteriorated similarly to the PPS.

  The raw material used to obtain the used paper pulp is a used paper material containing a used paper component derived from the used paper as a main component, and usually containing mechanical pulp. In the present invention, the mechanical pulp has a content ratio of 50% in all raw materials of the base paper (waste paper pulp, pulp such as mechanical pulp and other pulps, and all raw materials used when obtaining the base paper such as filler described later). The content ratio is, of course, calculated including the amount of mechanical pulp in the used paper raw material when obtaining used paper pulp such as used paper pulp.

  In the present invention, in order to obtain a used paper pulp, the waste paper raw material is disaggregated at a disaggregation concentration of 15% or more, further 16% or more, a disaggregation temperature of 50 ° C or less, and further a low temperature of 40 to 48 ° C. It is preferable to do. If the disaggregation concentration is less than 15%, the deterioration of the waste paper progresses due to the high shearing force accompanying disaggregation, and if the disaggregation temperature exceeds 50 ° C., there is a possibility that fine particles such as back glue may be made finer. The disaggregation concentration is preferably 22% or less, and more preferably 21% or less. If the disaggregation concentration is higher than 22%, the viscosity of the raw material increases, so that disaggregation does not proceed easily, and there is a possibility that a great amount of energy is consumed for the disaggregation treatment for a long time.

  It is preferable that the disaggregated waste paper pulp is beaten and the conditions at this time are, for example, 100 ° C. or less, more preferably 80 to 90 ° C., and the power consumption is preferably more than 50 kwh / t, further 60 kwh / t or more, particularly 75 kwh / t or more is preferable in terms of production efficiency and energy saving. On the other hand, if it exceeds 120 kwh / t, it will result in cutting the fiber by increasing the load, which will be negative in terms of energy and tend to be negative in pulp quality. Further, by performing a viscous beating treatment at a temperature of 100 ° C. or less, it is possible to obtain an internal fibril of the pulp fiber while reducing the risk of fiber cutting.

  As one of the features found by the present inventors in reusing used paper pulp, after the disaggregation step in the present invention, it is disaggregated at a disaggregation temperature of 50 ° C. or lower, and further at a low temperature of 40 to 48 ° C. This makes it possible to discharge foreign matter such as back paste that has not been refined to the outside of the system, and obtain external fibrils and internal fibrils by sticking used paper pulp with sticky beating. When such recycled paper pulp is used as a raw material, newsprint paper that is more bulky and has improved opacity can be obtained.

  In the present invention, prior to viscous beating, after dewatering and concentrating the waste paper pulp previously disaggregated with a pulper, a kneading process is performed using a kneader such as a known PFI mill, or a kneader such as a disperser or a kneader. Is preferred. The pulp concentration at the time of kneading is preferably as high as possible within the range permitted by the performance of the concentrating device or the kneading device, and the kneading treatment sufficiently reduces the fragmentation of the aggregated ash such as the filler added internally or the pigment in the coating liquid. In order to make it progress, it is preferable that this pulp density | concentration is 20 mass% or more, Furthermore, it is about 25-35 mass%.

  In addition, it is desirable that the Canadian standard freeness (hereinafter referred to as CSF) of waste paper pulp is not reduced as much as possible during kneading. If the CSF of the waste paper pulp is excessively lowered, not only the operability in the subsequent classification process is lowered, but also there is a possibility that the beating margin in the subsequent viscous beating process may be reduced.

  In the present invention, the viscous beating is preferably performed by beating the used paper pulp after the kneading treatment at a beating concentration of 2 to 5%. When the beating concentration of the waste paper pulp is less than 2%, the internal fibrillation and external fibrillation required by the beating effect do not proceed sufficiently and cutting of the pulp fibers occurs, so that the quality becomes difficult to be constant and the bulkiness is sufficient. May be difficult to obtain. On the other hand, if the beating concentration of the used paper pulp exceeds 5%, the amount of power consumed at the time of beating increases and the cost effectiveness is reduced, which is not preferable. The optimum beating pulp concentration is 2 to 4%, and the power consumption during beating is preferably in the range of 70 to 100 kwh / t, and the bulk becomes highest in the vicinity of about 80 kwh / t.

  For example, a normal disc refiner can be used for the viscous beating process. However, the disc refiner remains a transient viscous beating process due to centrifugal force at high speed rotation of the refiner, whereas a conical disc is used. The refiner is a centrifugal force generated by high-speed rotation of the refiner, and the flow vortex of the raw material generated in the groove between the beating blades increases the frequency at which the waste paper pulp fibers are repeatedly beaten by the beating blades. Beating is easy to progress. Therefore, it is preferable to use a conical disc refiner in this respect. In order to generate many flow vortices of the raw material, the blade width and the groove width are in the relationship of “blade width <groove width”, and unlike conventional refiners having a blade width of 2.0 mm or more, the blade width is 1. 5 mm or less, further 1.0 mm or less, the groove width is 1.5 mm or more, and a beating process may be performed with a rotary blade and / or a fixed blade having a groove depth three times or more the blade width. It is preferable for waste paper pulping of recycled paper. The optimum blade width and groove width are 1.3 mm and 2.4 mm, respectively. When using a conical type disc refiner under such conditions, even inside waste paper pulp made of newsprint waste paper that is flat and difficult to swell, internal fibrillation is possible. When pulp is used as a raw material, it is possible to obtain newsprint paper that is more bulky and has improved opacity.

  For example, when waste paper pulp is beaten at a low beating concentration of less than 2%, the beating process is performed continuously and in a short time, so the frequency with which the fibers come into contact with the beating blade is reduced, and uniform beating is difficult. , Causing a large amount of fine fibers to be generated. In particular, waste paper pulp derived from newsprint is made at least once and the moisture in the pulp fiber is removed, so that the fiber is flat and does not swell even when disintegrated with a pulper. Due to the peeling and cutting (cutting) of the paper, there is a risk that it will become a waste paper pulp which is difficult to be bulked and has many fine fibers.

  The viscous beating effect as described above is uniformly expressed with respect to the entire pulp fiber, and can promote both the internal fibrils and the external fibrils of the pulp fiber.

  Furthermore, by adjusting the power consumption of the viscous beating process and the pulp beating amount appropriately, foreign matter can be removed and dispersed while suppressing fiber deterioration and further flattening, and the bulky newsprint raw material can be renewed. Used paper pulp can be obtained.

  For example, in addition to the recycled paper pulp obtained as described above, as waste paper pulp, for example, tea waste paper, craft envelope waste paper, magazine waste paper, newspaper waste paper, leaflet waste paper, office waste paper, corrugated waste paper, upper white waste paper, Kent waste paper, imitation It can be used by appropriately selecting one or two or more kinds from among de-aggregated used paper pulp, de-aggregated / de-inked used paper pulp, de-aggregated / de-inked / bleached used paper pulp, etc. produced from used paper, old paper, etc. .

  In the present invention, the amount of used paper pulp is 20% by mass or more, more preferably 25 to 100% by mass of the total amount of pulp from the viewpoint of sufficiently imparting bulkiness while maintaining the blank opacity of the resulting newsprint. %, Particularly 30 to 100% by mass is preferred.

  As pulp which is a constituent component of newsprint paper, other than the waste paper pulp, for example, stone grand pulp (SGP), pressurized stone grand pulp (PGW), refiner ground, as long as the object of the present invention is not impaired. Mechanical pulp such as pulp (RGP), chemi-ground pulp (CGP), thermo-ground pulp (TGP), ground pulp (GP), thermo-mechanical pulp (TMP), chemi-thermomechanical pulp (CTMP), refiner mechanical pulp (RMP) 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), conifer semibleached kraft pulp ( NSBKP), Hardwood Acid pulp, such as chemical pulp such as soft wood sulfite pulp, be mentioned various known pulps, select one or more from among these can be appropriately used by adjusting the ratio.

  In the present invention, waste paper pulp derived from recycled paper is used as the raw material pulp, but in order to ensure bulkiness, printing opacity and stabilization of quality, the amount of mechanical pulp is adjusted to the total raw material of the base paper (above-mentioned The content ratio in waste paper pulp, pulp such as mechanical pulp and other pulp, and all raw materials used when obtaining the base paper such as filler described later) is 50% by mass or more, preferably 52 to 85% by mass, more preferably 54%. It adjusts so that it may become -80 mass%.

  The newsprint paper base of the present invention comprises at least a filler as well as the pulp.

The filler used in the present invention, or used paper pulp from bleached paper containing a large amount of rigid mechanical pulp, fibers are flat, macerating difficult to swell the fibers be treated with a pulper, the fiber surface during beating Due to peeling and cutting (cutting), calcite calcium carbonate and aragonite calcium carbonate are aggregated or crystallized in a chestnut shape, considering the use of waste paper pulp from newspaper waste paper that is difficult to bulk and has many fine fibers. a burr calcium carbonate, include the later-described playback particle agglomerates, chemically with such paper pulp, it is effective to hold between physical pulp fibers.

  In the process of obtaining calcium carbonate having a stable calcite type crystal structure such as a spindle type or a columnar shape, or a calcium carbonate having a metastable aragonite type crystal structure by reacting calcium hydroxide with a carbon dioxide-containing gas. 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 the spindle 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 100 to 100 according to “Pigment test method—Part 13: Oil absorption amount—Section 1: Refined linseed oil method” described in JIS K 5101-13-1. It is preferable that it is 150 ml / 100g, a BET specific surface area is 5-50 m < ² > / g, and a volume average particle diameter is 1.0-10.0 micrometers.

  If the amount of oil absorption of Hagi chestnut calcium carbonate is less than 100 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 150 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 the chestnut calcium carbonate is preferably 100 ml / 100 g or more, more preferably 110 ml / 100 g or more, and preferably 150 ml / 100 g or less, more preferably 140 ml / 100 g or less.

In addition, if the BET specific surface area of calcium chloride calcium carbonate is less than 5 m ² / g, voids in the aggregated structure may decrease, and ink absorbability may decrease. On the other hand, if it exceeds 50 m ² / g, the filler dispersion There is a risk that the dilution viscosity of the ink becomes high, the operability is lowered, and the printing density is lowered. Therefore, it is preferable that the BET specific surface area of Oguri calcium carbonate is 5 m ² / g or more, more preferably 10 m ² / g or more, and 50 m ² / g or less, more preferably 20 m ² / g or less.

  In the present specification, the BET specific surface area of Oguri calcium carbonate means a value measured with a high-speed specific surface area / pore distribution measuring device (model number: Asap 2420, manufactured by Shimadzu Corporation).

  Further, when the volume average particle size of the calcium chloride calcium carbonate is less than 1.0 μm, when added as a filler, it becomes easy to enter the gaps between the pulp fibers constituting the paper, and the paper structure possessed by the calcium chloride calcium carbonate. It is difficult to exert the effect of increasing the bulk of the paper, and as a result, the printability may be reduced. On the other hand, when the thickness exceeds 10.0 μm, the contact area with the pulp fiber is reduced. There is a possibility that powder may be generated and printability may be deteriorated. Therefore, the volume average particle diameter of the calcium chloride calcium carbonate is preferably 1.0 μm or more, more preferably 1.8 μm or more, more preferably 10.0 μm or less, and further preferably 9.6 μm or less.

  In this specification, the volume average particle size of calcium chloride calcium carbonate is a particle size distribution measuring device 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). It means a value measured with a laser type microtrack particle size analyzer, manufactured by Nikkiso Co., Ltd.

  Further, the aspect ratio (the ratio of the major axis to the minor axis (major axis / minor axis)) of the calcium chestnut calcium carbonate is 3.5 or less, and further 3 from the viewpoint of further improving the opacity and printability of newspaper. .4 or less, and from the viewpoint of sufficiently suppressing deterioration in quality of newsprint, it is preferably 2.0 to 3.3.

  In the present invention, in order to sufficiently improve the printability, printing opacity, whiteness, etc. of the intended newsprint, the above-mentioned calcium carbonate is added to the filler in an amount of 5% by mass or more based on the total amount of the filler. It is preferably contained in an amount of 20% by mass or more, particularly 40% by mass or more.

In the present invention, since the regenerated particle aggregate is contained as a filler together with the above-described calcium chloride calcium carbonate, the paper structure is further bulked, the cushioning property is imparted to the newsprint, and for example, the inking property of the cold set type ink is improved. In addition to further improvements, blank paper opacity, printing opacity, printability, etc. are further improved.

  As the regenerated particle aggregate, for example, the one having a porous aggregate structure and having an aluminum component that is cationic as a constituent component has high adhesion to used paper pulp, and is used in combination with calcium chloride calcium carbonate Therefore, it is preferable from the viewpoint that the yield in the paper layer and the gap between the fibers are easily generated, and the bulkiness is high, and the property of hardly causing the decrease in the paper quality strength is exhibited.

  In addition, the whiteness of the regenerated particle aggregate alone has a low contribution in normal newsprint paper, but when used in combination with the calcium chloride of the chestnut, the whiteness of the newsprint can be appropriately improved as a result. .

  As the regenerated particle aggregate, for example, a deinking floss discharged from a used paper processing step is a main raw material, and the main raw material is obtained through a dehydration step, a drying step, a baking step, and a pulverization step. The particles are aggregated so that the three components of calcium, silicon and aluminum are contained in the particles.

  For example, such regenerated particle aggregates can be recycled by firing deinked froth, and therefore do not require disposal such as landfill as waste, reducing environmental impact and saving resources. It greatly contributes to the transformation. Further, since the main raw material is deinking floss generated in the waste paper processing step, there is an advantage that it is inexpensive, the amount of new natural inorganic minerals to be used can be suppressed, and the manufacturing cost is sufficiently reduced. Furthermore, by using such a regenerated particle aggregate, the yield of ash during papermaking is high, and unlike ordinary calcium carbonate, for example, it does not cause wear deterioration of papermaking equipment such as wire wear, and the resin component is further reduced. By adsorbing to the regenerated particle aggregate in a fine state, it is possible to prevent pitch troubles due to aggregation of the resin component, hardly cause soiling of the papermaking equipment, and to produce newsprint paper with low cost and high operability. In addition, when used together with the above-described calcium chloride calcium carbonate, an excellent opacity equal to or higher than that of the conventional art is imparted to the newsprint, and the back-through and the paper break are remarkably reduced.

  In addition, when manufacturing the said regenerated particle aggregate, 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 the regenerated particle aggregate 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 discharge 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.

  The main raw material of the regenerated particle aggregate is, for example, deinking floss generated in a deinking process for producing deinked wastepaper pulp from wastepaper. In particular, deinking floss discharged in the recycling process of used paper is preferable because it is made of a material derived from papermaking raw materials and contains less impurities such as iron and other heavy metals. 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 particle aggregate has a stable composition. These deinking froths contain, for example, calcium carbonate, kaolin, talc, titanium dioxide, silica, alumina and the like as inorganic substances. In the present invention, it is desirable to use such deinking floss as the main raw material of the regenerated particle aggregate, and the proportion of deinking floss in the total raw material is 50% by mass or more, further 60% by mass or more as the solid content. It is preferable to do.

  Usually, the deinking floss is dehydrated by a dehydrating means such as a screen so that the water content is about 90 to 97% by mass, and further the water content is 50% by mass or less, further 25 by a dehydrating unit such as a screw press. It is preferable to dehydrate until it becomes -45 mass%, especially 30-40 mass%. If the moisture content exceeds 50% by mass, the drying energy cost in the next drying process may increase, or the particle size after drying may vary, resulting in difficulty in uniform firing. The processing temperature in the firing furnace is lowered, energy loss during heating is increased, and uneven firing of the raw material is likely to occur, which may make it difficult to proceed with uniform firing. Furthermore, the moisture in the exhaust gas increases, which may result in a decrease in the efficiency of recombustion treatment for dioxin countermeasures and an increased load on the exhaust gas treatment facility. On the other hand, if the water content is dehydrated to less than 25% by mass, the dehydration equipment increases in size and the dehydration energy cost may increase.

  The obtained deinked deinking floss (dehydrated product) is dried in advance. As the drying means, known means such as hot air drying can be used, but it is possible to use the hot air drying means which can be loosened while drying the deinking floss and further can be classified by specific gravity. it can.

  Specific examples of the hot air drying means that can be suitably used are such that the dehydrated material has a volume average particle size of 4000 μm or less, more preferably 300 to 3000 μm, particularly 500 to 2000 μm, using a loosening facility such as an impeller. While loosening, hot air is blown by hot air blowing means provided below the impeller equipment, and hot air drying is performed. Of the deinked floss that has been loosened and dried, the deinked floss having a low specific gravity is discharged from the outlet provided in the upper part of the hot air drying means, whereby drying and classification can be performed. As a suitable means for classification of the dry deinking floss, a classification means using a cyclone can be adopted.

  The particle size distribution of the dried and literated deinking floss (dried product) is such that the particles having a particle size of 5000 μm or less are 70% by mass or more, further 72% by mass or more, particularly 80% by mass or more in the volume distribution of the particle diameter. It is particularly preferable to adjust to. As described above, when the dried product is produced so that the particles having a particle size of 5000 μm or less are 70% by mass or more, the quality of the obtained regenerated particle aggregate becomes more uniform, and the possibility of practical use is further increased. Can do.

  The temperature of the hot air when the hot air drying means is adopted is preferably adjusted appropriately in consideration of the moisture content of the dehydrated product to be used in the drying process and the moisture content of the intended dried product, but for example, 100 to 200 ° C. It is preferable to set the degree.

  Thus, it is preferable that the moisture content of the dried material which passed through the drying process is adjusted to about 2 to 20% by mass, and further to about 5 to 15% by mass. If the moisture content of the dried product is lower than 2% by mass, it may be overfired in the next baking step, and conversely if it is higher than 20% by mass, it becomes difficult to reliably perform baking due to insufficient drying. There is a fear.

  Next, the deinked floss that has been dried and classified is sent to a baking process. Firing can be performed using a commonly used incinerator, such as a rotary kiln, fluidized bed furnace, floating furnace, stoker furnace, etc. Among them, a method by indirect heating using a hot air furnace or an electric furnace is a firing temperature control, This is particularly preferable because fine adjustment of the firing degree is easy. For example, in firing using a rotary kiln, firing by direct heating or combustion by indirect heating can be performed alone or in combination. For example, primary firing in a primary firing furnace is a direct heating kiln furnace, particularly an internal heat kiln furnace, secondary firing in a secondary firing furnace is an indirect heating kiln furnace, particularly an external heat kiln furnace in which the firing temperature can be easily adjusted. Each method can be adopted.

  The firing process may be one-stage firing, but is preferably at least two-stage firing, and more preferably at least two-stage firing with continuous equipment. If the firing process is at least two stages, firing unevenness is less likely to occur during firing by burning organic substances, and firing can be performed evenly. In particular, by making different physical means in the firing step, it is possible to avoid uneven firing and improve the firing rate.

  The firing temperature is such that ink pigments such as carbon black in the deinking floss, organic compounds such as fibers and polymers are burned, and the particles contain three components of calcium, silicon and aluminum. The temperature is not particularly limited as long as the temperature is sufficient and stable to form aggregates of regenerated particles aggregated in the firing step.

  When silica is contained in the deinking floss, there is a possibility that silica reacts with calcium and aluminum to produce aluminum calcium silicate having high hardness. In order to prevent the formation of such a material having high hardness, for example, it is considered to calcinate at a temperature of 500 ° C. or less. However, under such conditions, it is difficult to completely burn the organic compound, and as a filler Obtaining regenerated particle aggregates having useful levels of whiteness can be difficult.

  On the other hand, when the firing temperature exceeds 1000 ° C., the decomposition and sintering of inorganic substances such as calcium carbonate, kaolin, talc, titanium dioxide, silica, alumina, etc. contained in the deinking floss progress and increase in hardness. There is a possibility that much energy and time are required to grind the regenerated particle aggregate to a desired particle size.

  Thus, the firing temperature has a great influence on the whiteness and hardness of the regenerated particle aggregate to be produced. Therefore, as firing conditions, primary firing is 500 to 650 ° C., and secondary firing is 550 to 750 ° C. It is preferable that the primary baking is performed at 530 to 630 ° C, and the secondary baking is performed at 600 to 730 ° C. When the primary firing temperature is less than 500 ° C., the remaining amount of unburned matter is large, and the aggregate formation of the regenerated particles is insufficient. For example, the whiteness of the obtained regenerated particle aggregates may not be sufficiently improved. There is. Conversely, when the primary firing temperature exceeds 650 ° C., most of the calcium carbonate contained in the deinking floss is thermally decomposed and is difficult to use as a reusable material, such as calcium oxide and calcium silicate. May occur, and the resulting regenerated particle agglomerates may be melted by heat and may be extremely hard and reduce wire wear. On the other hand, when the secondary firing temperature is less than 550 ° C., the organic matter may not be sufficiently burned or firing unevenness may occur, and the whiteness of the resulting regenerated particle aggregate may not be improved. Conversely, when the secondary firing temperature exceeds 750 ° C., the surface of the regenerated particle aggregate that has been baked and agglomerated is exposed to a high temperature, which may cause melting to form an extremely hard melt. Because of the high temperature combustion, oxygen hardly reaches the regenerated particle core, and there is a possibility that firing unevenness or unfired parts are generated. Moreover, an unburned thing can be combusted, making the secondary baking temperature 50-120 degreeC higher than a primary baking temperature, preventing the overfire of the surface of a regenerated particle aggregate.

  Of course, the secondary firing temperature may be the same as the primary firing temperature. When the secondary firing temperature is set to the same temperature as the primary firing temperature, for example, if the temperature is set to 530 to 730 ° C., the firing proceeds slowly, the unburned material can be reduced, and the regenerated particle aggregate having sufficient whiteness can be obtained. A collection can be obtained. In this embodiment, the temperature difference between the primary firing temperature and the secondary firing temperature is based on the temperature at the upper end of the firing furnace.

  In the firing step, the oxygen concentration in the firing step is 0.05% or more, more preferably 0.1% or more, by at least one of means for blowing air into this step and means for exhausting air from within this step. It is preferable to adjust to 20% or less. In particular, the oxygen concentration in the firing step is desirably adjusted to 0.2 to 20%, more preferably 1 to 15%, and particularly preferably 5 to 12% at the upper end in the primary firing furnace. It is desirable to adjust to 5 to 20%, more preferably 10 to 20%, particularly preferably 15 to 18% in the vicinity of the burner of the next firing furnace. If the oxygen concentration at the upper end of the primary firing furnace is less than 0.2%, firing does not proceed and uneven firing proceeds, and there is a risk that enormous time and energy costs may be required for firing. is there. On the other hand, if the oxygen concentration in the vicinity of the burner of the secondary firing furnace exceeds 20%, it is easy to overheat, and the regenerated particle aggregates turn yellow due to overheating unevenness, and the regenerated particle aggregates frequently melt and decompose. Oxidation and oxidation may make it difficult to use as a filler. In the present embodiment, the moisture content of the dried and classified deinked floss (dried product) supplied to the firing step is preferably about 2 to 20% by mass, more preferably about 5 to 15% by mass. Therefore, if the oxygen concentration in the firing process is 0.05 to 20%, the firing can proceed extremely efficiently, and the firing can be performed within 90 minutes, resulting in extremely high productivity. Can be obtained. For example, baking can be performed in about 60 minutes by making the moisture content of a dried material into 10 mass%.

  Note that oxygen in the firing process is consumed by a burner or the like for firing, and the oxygen concentration in the firing process is reduced, but the oxygen concentration is maintained by blowing or exhausting an oxygen-containing gas such as air. It is possible to adjust the temperature in the firing process finely by blowing or exhausting oxygen-containing gas, and firing the regenerated particle aggregate uniformly and uniformly. Can do.

  The residence time in the firing process is not particularly limited, and may be adjusted so that firing is sufficiently performed according to conditions such as the firing temperature and the oxygen concentration in the firing process. For example, the residence time in the primary firing furnace The time is 30 to 90 minutes, further 40 to 80 minutes, particularly 50 to 70 minutes, and the residence time in the secondary firing furnace is 10 to 60 minutes, further 15 to 45 minutes, especially 20 to It is preferable to adjust so that it may be 40 minutes.

  The firing in the primary firing furnace is preferably performed so that the unburned rate is 5 to 30% by mass, further 8 to 25% by mass, and particularly 10 to 20% by mass. When the unburned rate after primary firing is less than 5% by mass, over-burning of the particle surface during firing occurs, the surface becomes hard, oxygen deficiency inside occurs, and the whiteness of the regenerated particle aggregate may be reduced. . On the other hand, when the unburned rate after primary firing exceeds 30% by mass, unburned matter remains after the subsequent burning and firing, or particles are cured by over-burning due to self-burning of unburned matter, In order to prevent the particles from remaining, they are burned and fired until the particle surface is overfired, and the regenerated particle aggregate surface may become hard.

  The fired particles can be finely granulated to a necessary particle size in a pulverization step, and regenerated particle aggregates usable as a filler can be obtained without agglomerating the fine particles after the pulverization step.

  For example, particles obtained by firing 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, and the desired regenerated particle aggregate It can be. The filler preferably has a uniform particle size and a fine particle size, and the proportion of aggregates having a particle size volume distribution of 20 μm or less is preferably 70% by mass or more.

  In the case of seeking further stabilization of the quality of the regenerated particle aggregate, it is preferable to classify the particle size of the regenerated particle aggregate in each step, and coarse particles and fine particles are fed back to the previous step. It is desirable.

  In addition, it is preferable to granulate the deinked floss that has been subjected to dehydration in the previous stage of the drying process, more preferably to classify the granulated product uniformly, and coarse granulated particles. Further, the quality can be further stabilized by feeding back the fine granulated particles to the previous process. For granulation, ordinary granulation equipment can be used, and for example, rotary, agitation, and extrusion equipment are suitable.

  Furthermore, it is preferable to remove foreign substances other than the aggregates of regenerated particles. For example, in the manufacturing process of deinked waste paper pulp, sand, plastic foreign substances, metals, etc. are removed with a pulper, screen, cleaner, etc. before the deinking process. It is preferable in terms of removal efficiency. In particular, iron content may reduce the whiteness of the regenerated particle aggregate by oxidation, and therefore it is preferable to avoid iron content and selectively remove it. The equipment in 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 high magnetic materials such as magnets are selectively installed in the drying / classifying equipment. It is preferable to remove iron.

In the drying step, the firing step, and the classification step as necessary, the particles having a particle size of 40 μm or less are preliminarily processed to be 80% by mass or more, and further 90% by mass or more before the pulverization step. It is preferable to keep it. Accordingly, a single-stage pulverization process by wet pulverization can be performed without performing a multistage pulverization process such as pulverization of coarse particles by dry pulverization and fine particle formation by wet pulverization. Moreover, by this, the average particle diameter in the differential curve of the particle size distribution by the laser particle size distribution measuring device (laser diffraction type particle size distribution measuring device SALD-2200 type, measured by standard refractive index (1), manufactured by Shimadzu Corporation) The peak height can be 30% or more. Furthermore, the pore volume of the regenerated particle aggregate is adjusted to 0.15 to 0.60 ml / g by adjusting calcium, silicon, and aluminum in the deinking floss as the main raw material in advance, for example, to a mass ratio described later. The pore surface area can be 10 to 25 m ² / g, and the pore radius can be 30 to 100 nm, so that the dispersibility of the regenerated particle aggregate and the blank opacity of newspaper can be improved.

  Furthermore, in the present invention, a silica-coated regenerated particle aggregate in which the surface of the regenerated particle aggregate obtained through the above-described steps is coated with silica can be suitably used as the regenerated particle aggregate as a filler.

  The silica-coated regenerated particle aggregate whose surface is coated with silica has a high porosity and a specific surface area that is dramatically increased. For example, it can be obtained by applying a beating process such as the above-mentioned waste paper process. Waste paper pulp fiber derived from recycled paper with many external fibrils and internal fibrils, excellent chemical and physical adhesion between fibers, higher printing opacity and better printability, especially offset at high speed Newspaper suitable for printing can be obtained.

  Silica is further precipitated on the surface of the regenerated particle aggregate to form a silica-coated regenerated particle agglomerate, so that it is reacted with sodium hydroxide in the used paper processing step in circulation use and used as a buffering agent or bleaching aid as a papermaking raw material. In addition, it can contribute to the recycling of inorganic particles. Further, when such a silica-coated regenerated particle aggregate is used as a filler, it is possible to impart porosity that contributes to the improvement of the opacity and ink absorption capacity possessed by silica, and the pulp fibers that constitute newsprint paper. When the silica-coated regenerated particle aggregate is contained in the gap, the displacement between the pulp fibers can be suppressed, and for example, the density can be prevented from excessively increasing in the flattening process. Furthermore, when such a silica-coated regenerated particle aggregate is used as a filler, the whiteness of the resulting newspaper is improved in combination with calcium chloride calcium carbonate, compared to the case of using a regenerated particle aggregate not coated with silica. It is possible to further improve effects such as improvement in the degree of ink, white paper opacity, surface strength, ink drying, etc., suppression of ink absorption unevenness, and provision of bulkiness.

  In addition, the deinking floss produced in the used paper processing step used in the present embodiment has a tendency to increase the content of calcium carbonate with the recent neutral paper making, the proportion of calcium in the obtained regenerated particle aggregate Tend to be higher. When the regenerated particle agglomerate having a high calcium ratio is used as a filler, the blank newspaper opacity of the resulting newspaper may be slightly reduced, but the silica-coated regenerated particle agglomerate with silica precipitated on the surface is The function as a regenerated particle for papermaking is very high, and the newspaper paper using the silica-coated regenerated particle aggregate as a filler has sufficiently improved white paper opacity and oil absorption.

  The silica covering the surface of the regenerated particle aggregate 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 has a shape such as a spherical shape, a chain shape, and an amorphous shape, in which impurities are removed from a silicic acid compound to form an anhydrous silicic acid sol, and the sol is stabilized by adjusting pH and concentration. Amorphous 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.

  There is no particular limitation on the method for obtaining silica-coated regenerated particle aggregates by precipitating silica on the surface of the regenerated particle aggregates. For example, the following methods can be suitably employed.

  First, regenerated particle agglomerates are added to and dispersed in an alkali silicate solution, and after preparing a slurry, the temperature of the liquid is maintained at about 70 to 100 ° C., more preferably at a predetermined pressure in a sealed container, while stirring with heating. An acid is added to form a silica sol. Subsequently, silica can be deposited on the surface of the regenerated particle aggregate by adjusting the pH of the final reaction solution to a range of 8 to 13. Silica deposited on the surface of the regenerated particle aggregate in this way reacts at a 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. And silica sol particles having a particle size of about 10 to 20 nm, which are obtained by hydrolysis reaction and polymerization of silicic acid.

  In addition, silica sol fine particles with a particle size of several nanometers, which are generated by adding an acid such as dilute sulfuric acid to an alkali silicate solution such as sodium silicate solution, cover the entire porous surface of the regenerated particle aggregate. As the silica sol fine particles grow, the silica sol fine particles on the surface of the inorganic fine particles are bonded to the silica particles on the surface of the regenerated particles by the bond formed between the silica sol fine particles on the surface of the inorganic fine particles and the silicon, calcium, or aluminum included in the regenerated particle aggregates. Can also be deposited. In this case, the pH when adding the acid to the alkali silicate solution is in a neutral to weakly alkaline range, and the pH is preferably adjusted in the range of 8-11. This is because if the acid is added until the pH reaches an acidic condition of less than 7, white carbon may be generated instead of silica sol particles.

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 particle aggregate is reduced and the silica content (SiO _{2) in the} solution is prevented so that silica does not easily precipitate on the surface of the regenerated particle aggregate. (Converted) is preferably 3% by mass or more, and the silica deposited on the surface of the regenerated particle aggregate becomes white carbon from the form of the silica sol, and the porosity of the regenerated particle aggregate is obstructed, opacity and printing In order to eliminate the possibility that the effect of improving the aptitude is insufficient, the silicic acid content is preferably 10% by mass or less.

  Thus, the regenerated particle aggregate suitably used in the present invention contains three components of calcium, silicon, and aluminum in the particle. In the 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 particle aggregate are converted to oxides, Calcium, silicon and aluminum are in a mass ratio of 30 to 82: 9 to 35: 9 to 35, more preferably 40 to 82: 9 to 30: 9 to 30, especially 60 to 82: 9 to 20: 9 to 20 It is preferably contained.

  In particular, when the regenerated particle aggregate is a silica-coated regenerated particle aggregate, in the elemental analysis by the X-ray microanalyzer, the particle component of the silica-coated regenerated particle aggregate includes calcium in terms of oxide. It is preferable that silicon, and aluminum and aluminum are contained in a mass ratio of 10 to 80:10 to 80: 5 to 29, more preferably 15 to 80:15 to 80: 5 to 25.

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

  The regenerated particle aggregate used in the present invention contains silicon, and the silica particles made of silicon are fine, so the optical refractive index is high. Therefore, for example, newsprint with a regenerated particle agglomerate containing silicon in an oxide equivalent or more in the above mass ratio has a particularly high blank paper opacity.

  In addition, for example, when a regenerated particle aggregate containing calcium in an amount of the above-mentioned mass ratio in terms of oxide is used as the filler, the whiteness of the newsprint obtained can be improved.

  In order to adjust the mass ratio of calcium, silicon and aluminum in the particle constituents of the regenerated particle aggregate within the above range in terms of oxides, it is preferable to originally adjust the raw material composition in the deinking floss, It is also possible to adopt a method of including a coating floss with a clear origin or a preparation step floss with a spray, etc., or a method of containing an incinerator scrubber lime in the drying step, firing step, and classification step as necessary. It is.

  For example, neutral paper-making wastewater sludge for the adjustment of calcium in recycled particle aggregates and wastewater sludge from the coated paper manufacturing process, and coated paper that is added in large quantities as an opacity improver for the adjustment of silicon. For the production of wastewater sludge, for the adjustment of aluminum, papermaking wastewater sludge using an acid papermaking system or other sulfuric acid band, or wastewater sludge from the high quality papermaking process in which a large amount of clay is used can be used.

  Further, in the regenerated particle aggregate, in order to adjust the total content ratio of calcium, silicon, and aluminum to 85% by mass or more 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 adopt a means for removing. In particular, iron is preferably a causative substance that lowers the whiteness by oxidation, and thus is preferably removed selectively.

  Further, the regenerated particle aggregate contains silicon, but since the primary particles of silica made of silicon are fine, the optical refractive index is high. Therefore, for example, when a regenerated particle aggregate containing silicon in an amount of the above-mentioned mass ratio in terms of oxide is used as a filler, it is possible to improve the blank paper opacity of newspaper paper obtained.

  The particle diameter of the regenerated particle aggregate suitably used in the present invention is 5 μm or more, more preferably 8 μm or more, in terms of yield in the pulp and prevention of loss of the regenerated particle aggregate into white water. Preferably, the volume average particle diameter is 20 μm or less, more preferably 18 μm or less, and particularly preferably 15 μm or less, from the viewpoint of maintaining printability and preventing clogging of the blade tip.

  The regenerated particle aggregate suitably used in the present invention is such that the ratio of aggregates having a particle size volume distribution of 20 μm or less is 70% by mass or more and the ratio of aggregates having a particle size volume distribution exceeding 18 μm. Is more preferably adjusted to 0.5 mass% or less.

  In this specification, the volume average particle size and volume distribution of the regenerated particle aggregate are measured with a laser particle size distribution measuring device (laser diffraction type particle size distribution measuring device SALD-2200, standard refractive index (1), The value measured by Shimadzu Corporation).

  Further, the regenerated particle aggregate has an oil absorption amount of 30 ml / 100 g in accordance with “Pigment Test Method—Part 13: Oil Absorption—Section 1: Refined Sesame Oil Method” described in JIS K 5101-13-1. As described above, it is preferably 40 ml / 100 g or more, 100 ml / 100 g or less, and more preferably 90 ml / 100 g or less. If the oil absorption amount of the regenerated particle aggregate is less than 30 ml / 100 g, there is little difference between the opacity of the blank paper and the printing opacity, and there is a risk that print back-through occurs or neppari occurs. If it exceeds 100 ml / 100 g, There is a tendency that the pH of the paper surface tends to be high, and the ink density may be lowered.

  In the present invention, when the amount of the regenerated particle aggregate used is too small, for example, in a calendar process on a paper machine, a smoothing effect is hardly exhibited, and the blank paper opacity of newspaper is sufficiently improved. In addition, since the printing opacity becomes insufficient, the rigidity of the newsprint becomes high, and the running property on the rotary press may be lowered, the recycled particle aggregate is 2% of the total amount of the filler in the filler. It is preferably contained in an amount of at least 5% by mass, more preferably at least 5% by mass. Conversely, if the amount of regenerated particle agglomerates used is too large, it is desirable in terms of surface properties and rigidity, but ash tends to fall off as it is transported in the printing press, resulting in reduced surface strength, Since there is a risk of occurrence of fluffing, printing white spots, paper dust and the like, the filler preferably contains 15% by mass or less, more preferably 10% by mass or less of the total amount of the filler. Further, in order to maintain blank paper opacity and printing opacity, ensure ink absorption and drying properties, and suppress back-through, the amount of the regenerated particle aggregate is preferably 7% by mass or more of the total amount of the filler in the filler. In particular, it is particularly preferable to adjust to 7.5% by mass or more.

As the filler is used together with calcium chestnut calcium carbonate and regenerated particle agglomerates, it suppresses the decrease in paper surface properties, smoothness and opacity when only calcium chestnut calcium carbonate is used, and only regenerated particle agglomerates are used. In this case, it is possible to suppress the decrease in whiteness, ink inking property, and ink absorption unevenness, and synergistic quality improvement can be achieved. In addition, in order to impart printability, bulkiness, etc. in a balanced manner to the target newspaper, the ratio of calcium chloride calcium carbonate and regenerated particle aggregates (calcium calcium carbonate: regenerated particle aggregates (mass ratio)) is 5: It is preferably 95 or more, more preferably 20:80 or more, and more preferably 80:20 or less, and even more preferably 60:40 or less.

In the present invention, the filler Ru are contained as the burr calcium carbonate and reproducing particle aggregates, in addition to these, within a range not impair the object of the present invention, such as white carbon, kaolin, engineered kaolin, clay, Delaminated clay, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, zeolite, barium sulfate, zinc oxide, aluminum oxide, magnesium oxide, silicic acid, colloidal silica, colloidal alumina, satin white and other inorganic fillers and organic Fillers can be used alone or in combination of two or more.

  The ratio of the filler to the pulp is 100 parts by mass of pulp solids in order to sufficiently exhibit the effects of improving the printing operability, printability, etc. while maintaining high printing opacity due to the use of the filler. On the other hand, it is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, and in order not to cause the generation of paper dust of newsprint, 20 parts by mass or less with respect to 100 parts by mass of pulp solids, Furthermore, it is preferable to set it as 15 mass parts or less.

In order to obtain the base paper constituting the newsprint of the present invention, a filler is added to the pulp slurry made of the pulp, for example, preferably pH 6.0 to 10.0, and more preferably pH 6.5 to 9.5. It is possible to adjust the conditions such as pH so that it becomes neutral to alkaline, and adopt a method of making paper with a normal paper machine such as a long net paper machine or a twin-wire paper machine. It is preferable from the point of improving. That is, when, for example, calcium chestnut calcium carbonate is used as a filler, the papermaking pH becomes about 7 to 9 due to its buffer effect. When the papermaking pH is neutral to alkaline, each fiber easily swells compared to the case of acidity, and the area for forming hydrogen bonds between fibers that are externally fibrillated and internally fibrillated increases. Therefore, when the ash content is about the same as that of acid newsprint paper, the neutral newsprint paper has a higher paper strength. As a result, sufficient quality that can withstand high-speed offset printing can be ensured even for newspapers with a low basis weight, such as 35-50 g / m ² .

  Further, in the present invention, when obtaining the base paper, it is possible to add a coagulant in the pulp preparation stage and further add a flocculant in the first stage of the papermaking process following the pulp preparation stage. This is preferable because it promotes agglomeration of fine inorganic particles and further adheres inorganic particles to the raw material pulp to improve filler yield, and improves drainage and wet end stability.

  Since the recycled paper pulp used in the present invention has a high proportion of mechanical pulp and a relatively high anionic property on the pulp surface, a coagulant is added during the pulp preparation stage, and further the papermaking following the pulp preparation stage. The addition of a flocculant at the pre-stage of the process allows the filler to be physically and chemically adhered between the pulp fibers to improve the filler yield, and the wet end stability can be obtained by improving drainage. To preferred.

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

  The organic polymer-based coagulant is, for example, in the case of using calcium chestnut calcium carbonate and regenerated particle aggregates together, the regenerated particle aggregates can be retained in the pulp, and the charge density can be improved. 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 fixation of the calcium chloride or regenerated particle aggregate to the wet paper may be insufficient, and as a result, the intended effect may not be improved. If it exceeds 1.3 million, the cohesive force is too strong, so the paper fit of the newsprint decreases, and in order to maintain the paper fit well, the amount of addition must be reduced, and also the intended effect is improved. There is a fear that I can not hope.

  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, the addition amount of the organic polymer coagulant depends on the addition amount of the inorganic coagulant described later, but is preferably 1000 to 4000 ppm, more preferably 1200 to 3800 ppm in solid content with respect to the pulp. . 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, the addition amount of the inorganic coagulant is 0.1 to 5.0% by mass, further 0.1 to 3.0% by mass, particularly 0.1 to 2.0% by mass with respect to the pulp. Is preferred.

  In the present invention, as described above, it is preferable to add a coagulant in the pulp preparation stage. For example, the pulp and filler, and if necessary, an internal sizing agent, a fixing agent, a yield improver, a cation Various paper-making aids such as an 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.

  Furthermore, in the present invention, it is preferable to add a coagulant in the stage before the paper making process following the pulp preparation stage after adding the coagulant in the 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 quantity of the chestnut calcium carbonate and reproduction | regeneration particle | grain aggregate which are missing | missed in a papermaking net | network can be reduced significantly.

  Moreover, it is preferable that the addition amount of a flocculant is 100-150 ppm with a pure part with respect to a pulp, Furthermore, it is preferable that it is 120-140 ppm. If the addition amount of the flocculant is less than 100 ppm, there is a possibility that the yield improvement effect of the chestnut calcium carbonate and the regenerated particle agglomerates may not be sufficiently obtained. On the other hand, if it exceeds 150 ppm, the formation of the newsprint may be lowered. is there.

  In the present invention, for example, by using the above-mentioned coagulant or flocculant, the final newspaper paper has a formation index of 5.0 to 10.0%, further 6.0 to 9.5%, and particularly 8. It is preferable to adjust to 0 to 8.5%. The newsprint of the present invention requires a predetermined tensile strength because it is mainly printed on a rotary press. Therefore, in order to obtain a predetermined tensile strength in the longitudinal direction, the formation index is preferably 5.0% or more. On the other hand, even if the formation index exceeds 10.0%, 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, and printability, particularly printing opacity. There is a risk of lowering.

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

  Furthermore, when producing the base paper constituting the newsprint of the present invention, before preparing a plurality of stocks and supplying them to the seed box, the slurry of each stock was subjected to an on-line cation demand measuring device and measured. It is also possible to control the amount of coagulant added in the preparation stage based on the cation demand measurement.

  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, including pulp (including fine fibers), fillers (preferably used calcium chestnut calcium carbonate, regenerated particle aggregates, etc.), various wet substances. End paper making aids (other fillers, internal sizing agents, antifoaming agents, etc.), resin pitch, elution lignin and the like.

  A typical example of an apparatus for measuring 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.

  Next, a coating liquid containing a water-soluble polymer compound is provided on the surface of the base paper, so that the newsprint of the present invention can be obtained.

  Examples of the water-soluble polymer compound contained in the coating solution include starch, polyvinyl alcohol (hereinafter referred to as PVA), and the like, and these can be used alone or at the same time, and in particular, starch is used as a main component. Is preferred.

In the present invention, waste paper pulp mainly composed of recycled paper pulp is used as raw material pulp, but the recycled paper pulp contains a lot of mechanical pulp, its pulp fiber is rigid, and fine beating on the fiber surface. There are fibril fibers. By adding 0.2 to 5.0 g / m ² of a water-soluble polymer compound as a solid content on the surface of the paper having this rigid waste paper pulp and fine fibril fibers, it is preferable to use a known machine calendar or software. By flattening with a flattening equipment such as a calendar, the surface of the paper is secured with a water-soluble polymer compound while keeping the fibers and fibrils protruding from the paper surface flat, maintaining the bulkiness of the paper. However, it is possible to satisfy printability that can withstand high-speed rotary printing.

  The type of starch is not particularly limited, but in the present invention, for example, esterified starch or oxidized starch can be suitably used, and esterified starch is particularly preferable.

  For example, although modified starch has the effect of improving tensile strength and surface strength while penetrating into paper, it exhibits neutrality or anionic property, so it has low fixability on the surface of an anionic pulp fiber and has a 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. Further, when esterified starch or oxidized starch is used, the fixability to pulp fibers is high, the coating property is excellent, and the quality of the newspaper paper surface is improved.

  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. Furthermore, the esterified starch having thixotropic properties exhibits fluidity when applied to the surface of the base paper, but does not easily penetrate into the base paper after coating, and exhibits high coating properties on the surface of the base paper. preferable.

  As the oxidized starch, conventionally used modified starch is preferably exemplified. For example, by oxidation reaction with sodium hypochlorite or the like, the molecular weight is reduced, and carboxyl groups, aldehyde groups, carbonyl groups, etc. The one that has been introduced.

  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 used as a 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.

Further, as the starch, fibers (fibrils) having a viscosity (10%) of 30 × 10 ⁻³ Pa · s or less, and further having a viscosity of 15 × 10 ^{−3 to} 25 × 10 ⁻³ Pa · s are projected on the paper surface. In the flattening of the fibers, it is preferable from the viewpoint that it can remain on the paper surface without penetrating into the paper because of its high viscosity.

  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 surface of a newsprint, it exhibits approximately three times the surface strength compared to the case where starch is applied alone, and is excellent in coating properties, but has high coating properties. In addition, when a printing ink that is dried by the penetration of a solvent into the paper, 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 trying to apply a certain amount of PVA alone, the viscosity of the coating solution containing the PVA is high. 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, while suitably promoting the penetration of the solvent of the printing ink into the paper, the film property for retaining the ink filler component on the paper surface is improved and the ink setting property is lowered. Also has the advantage of being 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 starch and PVA are used in combination, the ratio of the two (starch: PVA (solid content mass ratio)) is 10: 0.8 to 10: 2.0, and further 10: 0.9 to 10: 1.2. It is preferable that When the ratio of PVA to starch exceeds 10: 2.0, the viscosity of the coating liquid 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 in the compatibility between starch and PVA, but when applied to the surface of the base paper, a synergistic effect between starch and PVA is obtained. This may cause penetration into the base paper and uneven coating. In particular, calcium carbonate such as Oguri calcium carbonate is used as the filler, and when the calcium carbonate is present in an amount of 10% or more by a surface analysis of the surface of the base paper with an X-ray microanalyzer, Since the bonding between fibers is more likely to be inhibited than in the case of using, the coverage with starch and PVA is lowered, and the ink absorption drying property on the paper surface may be inhibited. Therefore, by setting the ratio of both in this range, a synergistic effect between starch and PVA, and further a synergistic effect with the filler constituting the base paper can be ensured. A high ink density can be expressed by staying on the surface, and at the same time, the solvent in the ink can be quickly absorbed into the newspaper and a fast ink setting property can be expressed.

  The coating liquid to be applied to the surface of the base paper is, for example, a water-soluble polymer compound such as starch or PVA and, if necessary, a surface paper strength agent such as polyacrylamide, or a surface such as styrene-based polymer. It can be obtained by appropriately mixing the sizing agent, adding water, and appropriately adjusting the solid content concentration.

For example, a coating solution containing a water-soluble polymer compound such as starch or PVA can be applied to the surface of the base paper by a known coating method, and among these, it is preferable to apply by a film transfer method. Coating by the film transfer method, particularly coating by a gate roll, unlike other coating methods, covers the surface of the base paper at a low coating amount of, for example, 0.5 to 1.0 g / m ² . The coating solution is optimal when applying a high contour coating, and since the coating solution is not subjected to a rapid shearing force, the coating solution used in circulation is excellent in stability, and a uniform coating can be obtained at high speed.

  For example, the coating liquid mainly composed of starch and PVA can be applied by a coating means such as a size press or a rod metaling size press, not the film transfer method, but the surface of the base paper If the contour coating is not applied along the unevenness of the surface, the covering property by starch and PVA is not sufficiently exhibited. For example, when multicolor offset rotary printing is performed using a cold set type ink, the ink density and the ink setting property In addition, it is difficult to obtain newsprint paper with excellent printability such as ink fillability. Therefore, the film transfer method is suitable for applying a coating solution mainly composed of starch and PVA at a low concentration and a low coating amount.

The coating amount of the coating liquid on the surface of the newsprint is such that the water-soluble polymer compound is 0.2 g / m ² or more, preferably 0.5 g / m ² or more, in terms of solid content on the paper surface. .0g / m ² or less, are preferably adjusted so as to be contained 4.0 g / m ² or less. If the amount of the water-soluble polymer compound contained in the paper surface is less than 0.2 g / m ² , sufficient film properties with the water-soluble polymer compound cannot be obtained, and the filler component in the ink is the surface of the newspaper paper. Insufficient ink density cannot be obtained. On the other hand, if the amount of the water-soluble polymer compound contained on the paper surface exceeds 5.0 g / m ² , a large amount of coating solution mist containing the water-soluble polymer compound is generated around the coating equipment. In addition to fouling the equipment, paper breaks and paper defects are caused by the dirt.

As described above, in the present invention, starch is used as the main component of the water-soluble polymer compound, and PVA is used in combination, and the ratio of both (starch: PVA (solid content mass ratio)) is 10: 0.8-10. : It is optimum that the starch and PVA are contained in a solid content of 0.2 to 5.0 g / m ² in the coating layer formed on the paper surface by the coating liquid of 2.0. . As a result, for example, the pigment component of cold set type offset ink can be sufficiently retained on the surface of the newsprint, and the solvent (vehicle) permeability in the Z-axis direction of the newsprint can be further improved. By developing the concentration and obtaining a suitable solvent permeability, the ink setting property of the cold set type offset ink is further improved.

  In addition, to improve the ink setting properties of offset ink, it is also effective to apply starch, but by simply applying starch, cold set offset ink can be sufficiently retained on the surface of newsprint paper. By adjusting the solid content of the water-soluble polymer compound contained in the coating layer formed on the surface of the paper so that it falls within a specific range as in the present invention, cold set type offset ink It is possible to keep the pigment component on the surface of the newsprint and allow the solvent to permeate appropriately in the direction of the newsprint Z-axis, with good ink setting, high ink density, and high-definition printed images and print defects. Transparency can be obtained.

  Furthermore, the newspaper of the present invention can be subjected to a flattening process using a calendar facility such as a super calendar, a gloss calendar, or a soft calendar.

The newspaper of the present invention thus obtained has a basis weight in accordance with the “basis weight measuring method” described in JIS P 8124, preferably 35 g / m ² or more, from the viewpoint of reducing labor in transportation and reducing weight. The weight is preferably 38 g / m ² or more, preferably 50 g / m ² or less, more preferably 48 g / m ² or less. When the basis weight is less than 35 g / m ² , the opacity cannot be ensured sufficiently, and particularly in recent high-speed printing, which reaches 170 to 180,000 copies / hour, paper breakage and wrinkles are likely to occur. There is a risk of quality problems. On the other hand, when the basis weight exceeds 50 g / m ² , it becomes easy to secure sufficient opacity, but it is difficult to handle as lightweight newsprint.

  Ash content in newsprint is measured in accordance with “Paper, paperboard and pulp-ash content test method—525 ° C. combustion method” described in JIS P 8251, and is 4.0% or more, and further 6.0% or more. In particular, it is preferably 7.0% or more, 15.0% or less, more preferably 12.0% or less, and particularly preferably 10.0% or less.

  For example, waste paper pulp made from conventional newspaper wastepaper contains mixed paper such as leaflets. It is necessary to adjust the overall ash content while taking into account the ash content. The ash content in the paper increases due to the inadvertent presence of ash content, the paper strength decreases and paper breaks occur, resulting in poor operability. Had. In addition, the ash derived from waste paper is easy to fall off after paper making, and also causes frictional sites in the printing press and paper dust when cutting. Therefore, it is preferable to keep the carried ash content in the waste paper raw material as low as possible.

  In the newsprint of the present invention, used paper pulp containing recycled paper pulp is used as the pulp constituting the base paper, and therefore, different from the used paper pulp made of conventional newsprint, mixed paper such as flyers is mixed. As a result, there is little ash derived from waste paper, and the carried ash content in the waste paper raw material can be kept low.

  If the ash content in the newsprint is less than 4.0%, sufficient opacity is difficult to obtain, which may cause show-through. In particular, in the case of high whiteness, if the ash content is too small, the show-through tends to be noticeable. On the other hand, if the ash content exceeds 15.0%, the paper strength is liable to decrease as described above, causing a paper-cutting trouble in the paper-making process, resulting in a decrease in productivity and the possibility of contamination in the system. There is a tendency for paper breakage in high-speed rotary printing to occur, which may cause a decrease in printing operability.

  The paper surface pH of the newsprint is preferably 6.0 or more, more preferably 6.5 or more, and is preferably 10.0 or less, more preferably 9.5 or less. Especially in high-speed rotary offset printing on newsprint, the dampening solution applied to the paper before printing varies depending on the newspaper company, but it is almost neutral. In order to reduce the risk of occurrence of defects, it is preferable to adjust to such a paper surface pH range.

  In the present specification, the pH of the paper is visually determined with a color change standard meter using a reagent (MPC-BCP, pH 4.8 to 6.8) with a pH measurement kit for paper (manufactured by Kyoritsu Riken). The measured value.

The density of the newsprint is measured according to the method described in “Paper and paperboard—Test method for thickness and density” described in JIS P 8118, 0.5 to 1.0 g / cm ³ , Is preferably 0.6 to 0.9 g / cm ³ . When the density is less than 0.5 g / cm ³ , the paper strength decreases, which may cause a paper break in high-speed rotary printing and a problem that paper dust is generated. On the other hand, if the density exceeds 1.0 g / cm ³ , it becomes easy to cause a back-through after printing, and the rigidity may be lowered and the printing workability may be lowered.

  Further, the whiteness of the newsprint is 55% or more, more preferably 55.5 to 58, as measured according to “Pulp—Diffusion Blue Light Reflectance (ISO Whiteness) Measurement Method” described in JIS P 8212. % Is preferred. When the whiteness is less than 55%, not only the white paper appearance before printing is degraded, but also the appearance of the printed matter after offset printing, particularly after color printing, may be degraded.

  The blank paper opacity of the newsprint is 88% or more, more preferably 85 to 94%, as measured according to “Paper and paperboard—Opacity test method (paper backing)” described in JIS P 8149. It is preferable. If the blank paper opacity is less than 88%, not only the appearance of the blank paper before printing is deteriorated but also the appearance of the printed matter after the offset printing may be lowered.

  The printing opacity after printing on the newsprint of the present invention is preferably 0.5% or more, more preferably 0.8 to 2.0% higher than the blank paper opacity.

  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.

Reference Examples 1 to 13 (Production of regenerated particle aggregate)
Using deinking floss as raw material (deinking floss discharged from waste paper treatment process for producing deinked waste paper pulp, solid content of 100% by mass), the dehydration process, drying process and firing process are performed under the conditions shown in Table 1. Sequentially, the particles were aggregated in the firing step, and then wet pulverization was performed to obtain a regenerated particle aggregate.

In Production Examples 8 and 9, a regenerated particle aggregate was added to and dispersed in a sodium silicate solution (water glass) to prepare a slurry. Sulfuric acid was added to produce a silica sol. Next, the final reaction solution was adjusted to the pH shown below, and silica was deposited on the surface of the regenerated particle aggregate to obtain a silica-coated regenerated particle aggregate.
Liquid temperature (° C): 90 ° C
Final reaction solution (pH): 9

  Regarding the obtained regenerated particle aggregate (and silica-coated regenerated particle aggregate), the content of calcium, silicon and aluminum (as oxide) in the particle constituents, and the total content of calcium, silicon and aluminum (oxide) Conversion), volume average particle size, proportion of aggregates of 20 μm or less in the volume distribution of the particle size, oil absorption, appearance, wire wear, productivity, and quality stability. These results are shown in Tables 2 and 3.

  Various measured values shown in Tables 1 to 3 were measured by the following methods.

(A) Moisture content of dehydrated product and dried product Samples were collected and measured in accordance with “paper and paperboard—moisture test method—method using dryer” described in JIS P 8127.

(A) Volume average particle size and particle size distribution of dried product at the entrance of the primary firing process An X-ray microanalyzer (model number: EMAX2770, manufactured by Hitachi, Ltd./Horiba, Ltd.) was used at an acceleration voltage of 15 kV. 20 X-ray images of X-ray microanalyzer display were taken and measured with a black and white polaroid film (Polaroid, 8.5 cm × 10.8 cm).

(C) Unburned rate after primary firing After heating the electric muffle furnace to 600 ° C in advance, the sample was put in a crucible and completely burned in about 3 hours, and the unburned content was calculated from the change in weight before and after burning.

(D) Oxygen concentration in the upper end of the primary firing furnace and in the vicinity of the burner of the secondary firing furnace This was measured with a gas analyzer (model number: PG250 type, manufactured by Horiba, Ltd.).

(E) Content of calcium, silicon and aluminum in the regenerated particle aggregate (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 particle aggregate was calculated from the contents of these calcium, silicon, and aluminum.

(F) Volume average particle diameter and volume distribution of regenerated particle aggregate 10 mg of the regenerated particle aggregate sample was dispersed for 3 minutes with an ultrasonic disperser (output: 80 W). Using this, a laser particle size distribution measuring device (laser diffraction type particle size distribution measuring device SALD-2200 type, measured with standard refractive index (1), manufactured by Shimadzu Corporation) with an average particle size of 20 μm or less. The proportion of certain aggregates was measured.

(G) Oil absorption amount A sample was collected and measured in accordance with “Pigment test method—Part 13: Oil absorption amount—Section 1: Refined linseed oil method” described in JIS K 5101-13-1.

(H) Appearance The color of the regenerated particle aggregate was visually observed and divided into white and gray.

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

(G) Productivity Each of the raw material dewatering 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.

(C) Quality stability The degree of variation was measured for each item of whiteness, particle diameter, and production volume at regular time intervals, 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 3, it can be seen that the regenerated particle aggregates of Reference Examples 1 to 13 all have high whiteness, low wire wear, and excellent productivity and quality stability. .

Production Examples 1-14 and Comparative Production Examples 1-7 (Manufacture of base paper)
Under the conditions shown in Table 4, the recycled waste paper and / or waste newspaper was kneaded with a pulper, kneaded with a kneader, and then beaten with a conical disc refiner (Comparative Production Example 4 had no sticky beating treatment). Recycled waste paper pulp and / or newspaper waste paper pulp were produced. The obtained waste paper pulp and mechanical pulp (TMP) were blended at a ratio shown in Table 5, and the CSF was adjusted to about 100 to 200 mL.

  In this pulp, 0.4 kg (solid content) of alkyl ketene dimer sizing agent (product name: AD-1624, manufactured by Nippon PMC Co., Ltd.) with respect to 1 t of pulp solid content, and Table 6 with respect to 100 mass parts of pulp solid content. A filler comprising the varieties A and B shown in Table 6 was added at a ratio shown in Table 6, and a coagulant shown in Table 7 was further added to obtain a pulp slurry.

The fillers shown in Table 6 are as follows.
Chestnut: Chestnut calcium carbonate Spindle type: Spindle type Calcium carbonate Spherical: Spherical calcium carbonate Needle: Needle-like calcium carbonate Column: Columnar calcium carbonate Heavy: Heavy calcium carbonate White: White carbon (wet silica)

  The ratio of the filler shown in Table 6 (variety A: variety B (mass ratio)) is randomized as a 500-fold image by electron beam probe microanalysis using ash obtained according to JIS P 8251 as a sample. About 10 places selected, the ratio of calcium and silica in terms of oxide was measured, and the measurement results at these 10 places were averaged. The measurement was performed using an X-ray microanalyzer (model number: E-MAX, manufactured by Hitachi, Ltd.) and an electron microscope (manufactured by Shimadzu Corporation) under the condition of an acceleration voltage of 15 kV.

Moreover, the physical property of the white carbon used as a filler (variety B) of the comparative examples 1 and 4 shown in Table 6 is as follows.
Secondary particle diameter Oil absorption amount comparison example 1: 15 μm 221 ml / 100 g
Comparative Example 4: 15 μm 222 ml / 100 g

  Then, the flocculant shown in Table 7 was added to the obtained pulp slurry, and paper was made with a long net paper machine at the paper making pH shown in Table 7 to produce a base paper. Moreover, the content rate of the mechanical pulp in all the raw materials of a base paper is combined with said Table 5, and is shown. The total raw materials are all raw materials used for obtaining the base paper such as pulp, filler, sizing agent, coagulant, and flocculant, and the content ratio of the mechanical pulp is used to produce used paper pulp. It is calculated including the amount of mechanical pulp in the used paper raw material used in the process.

In addition, the coagulant | flocculant and flocculant which are shown in Table 7 are as follows.
PAm: Polyamine PEI: Polyethyleneimine PAM: Polyacrylamide

Examples 1-14 and Comparative Examples 1-7 (Manufacture of newsprint)
On the front and back surfaces of the base paper obtained as described above, a water-soluble polymer compound shown in Table 8 and water were stirred and mixed, and a coating liquid having a solid content concentration adjusted to about 3 to 6% was obtained. 8 was applied so that the water-soluble polymer compound was contained in the coating amount shown in Table 8 (Comparative Example 4 had no coating solution applied) to obtain a newspaper. .

The water-soluble polymer compounds shown in Table 8 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 9.

(A) PPS
According to ISO 8791-4, "Paper and board - Roughness smoothness testing method (air leakage method) - Part 4: Print Surf method" conforming to, PPS TE ST ER (SE- 115 type, Lorentzen and Bet (Manufactured by Rye Co., Ltd.), and using a soft rubber packing disk, the PPS on the paper surface was measured under a clamp pressure of 1 MPa.

(B) Regular reflection type smoothness Using a regular reflection type smoothness meter (Microtopograph, manufactured by Toyo Seiki Seisakusho Co., Ltd.), under the conditions of 20 kg / cm ² pressure, light wavelength of 0.5 μm, and measurement time of 100 MS. The sample was measured 10 times, and the average value of the remaining seven data excluding the data from the largest to the third was calculated to obtain the regular reflection type smoothness of the paper surface.

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

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

(E) 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.

(F) Density The density was measured in accordance with “Paper and paperboard—Test method for thickness and density” described in JIS P 8118.

(G) Geometric Index Measured with a sheet formation tester (manufactured by Toyo Seiki Seisakusho).

(H) Whiteness Measured according to “Pulp—Diffusion Blue Light Reflectance (ISO Whiteness) Measurement Method” described in JIS P 8212.

(I) Blank paper opacity It was measured in accordance with “Paper and paperboard—Opacity test method (backing of paper)” described in JIS P 8149.

(J) Opacity of printing Offset rotary printing press (model number: RI-2, manufactured by Ishikawajima Industrial Machinery Co., Ltd.), offset rotary printing ink (trade name: News Zet Naturalis (black), Dainippon Ink and 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.

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

(L) Ink Concentration Using an RI printing aptitude tester (model number: RI-2 type, manufactured by Ishikawajima Industrial Machinery Co., Ltd.), offset printing ink (trade name: News Zet Naturalis) in the gap between the metal roll and the rubber roll. (Black), Dainippon Ink & Chemicals, Inc., ink usage: 0.85 ml), and printing at a speed of 30 rpm (test piece: CD direction 50 mm, MD direction 100 mm) It was dried for 24 hours according to “Paper, paperboard and pulp-standard conditions for humidity conditioning and testing” described in JIS P8111. About this print sample, the ink density | concentration of 25 printing parts selected at random was measured with the Macbeth densitometer, and these average values were calculated | required. If the ink density is less than 0.8, there is a possibility that a desired ink density may not be obtained in, for example, offset rotary printing in a newspaper company. Conversely, if the ink density exceeds 1.2, the ink density is sufficient. However, there may be a decrease in printing opacity and a problem of set-off.

  Next, each characteristic was investigated about the newsprint of Examples 1-14 and Comparative Examples 1-7 based on the following test examples 1-5. The results are shown in Table 10.

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 (black), 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 printer (model number: Komori SYSTEMC-20, manufactured by Komori Corporation), continuously 10,000 newspaper newspapers (trade name: News Zet Naturalis (black), manufactured by Dainippon Ink & Chemicals, Inc.) Copies were printed. 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)
Ink tack 18 using a color change tester (model number: RI-1 type, manufactured by Ishikawajima Sangyo Co., Ltd.) in accordance with “lithographic ink—Part 1: test method” described in JIS K5701-1. The printing was performed under the conditions of the first printing. 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), printing with newspaper ink (trade name: News Zeta Naturalis (black), manufactured by Dainippon Ink & Chemicals, Inc.) went. The obtained printed matter was visually observed for ink density unevenness 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 and 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.

All the newsprints of Examples 1 to 14 include recycled paper pulp as pulp constituting the base paper, the content ratio of mechanical pulp in all raw materials of the base paper is 50% by mass or more, and the filler is, A water-soluble polymer compound in the coating liquid contains 0.2 to 5.0 g / m ^{2 on the} surface of the paper containing calcium chloride and calcium carbonate and regenerated particle aggregates mainly composed of deinked floss. These are contained in specific amounts. Therefore, as shown in Tables 9 and 10, all the newspapers of Examples 1 to 14 have a PPS of 4.0 to 5.5 μm and a regular reflection type smoothness of 9 to 14%. The basis weight is 35 to 50 g / m ² , the weight is light, the ash content is 7 to 15%, the paper surface pH is 6 to 10 neutral to alkaline, the bulk is high, and the whiteness and white paper opacity are high. It can be seen that high printing opacity is maintained. In addition, all the newspapers of Examples 1 to 14 have a reasonably high ink concentration in the range of 0.8 to 1.2, but also have good ink setting properties and ink inking properties and excellent printability. It can be seen that the surface strength is high, the printing operability is excellent, and particularly excellent properties suitable for high-speed offset rotary printing are provided.

Both newsprint Comparative Examples 1-4, on the other hand, contains only recycled newspaper pulp does not contain a further paper waste paper pulp as a pulp constituting the base paper, coagulation playback particles burr calcium carbonate as a filler The aggregate is not used together, and the water-soluble polymer compound in the coating liquid is not contained in the range of 0.2 to 5.0 g / m ^{2 on} the paper surface (Comparative Examples 1 to 3). In addition, since the coating liquid containing the water-soluble polymer compound is not applied (Comparative Example 4), the PPS and / or regular reflection type smoothness is out of the above range, and the whiteness and blank paper opacity. Is insufficient and the printing opacity is low. Moreover, all the newspapers of Comparative Examples 1 to 4 have a low ink concentration, poor ink setability and ink fillability, uneven ink coloring, low surface strength, poor print operability, etc. It can be seen that it does not have the characteristics necessary for high-speed offset rotary printing.

  In addition, the newspapers of Comparative Examples 5 to 7 also contain only newspaper waste paper pulp, not recycled paper pulp, as the pulp constituting the base paper, which is also inferior in ink setting properties and ink setting properties, or uneven ink coloring. It can be seen that the ink does not have the characteristics necessary for high-speed offset rotary printing, such as the occurrence of printing, low surface strength, and poor printing operability.

  The newsprint of the present invention can be suitably used for offset rotary printing at a high speed of, for example, 170 to 200,000 copies / hour.

Claims (4)

Newspaper paper in which a coating liquid is coated on the surface of a base paper comprising at least constituent pulp containing waste paper pulp and filler,
Waste paper pulp derived from used paper is used as the waste paper pulp, and the content ratio of mechanical pulp in all raw materials of the base paper is 50% by mass or more,
The filler contains regenerated particle aggregates mainly composed of calcium chestnut calcium carbonate and deinked floss,
A water-soluble polymer compound is contained in the coating liquid, and the water-soluble polymer compound is contained in a solid content of 0.2 to 5.0 g / m ² on the paper surface.
In accordance with the method described in ISO 8791-4, using a soft rubber packing disk, the Parker Print Surf surface roughness of the paper surface measured under the condition of a clamp pressure of 1 MPa is 4.0 to 5.5 μm,
Using a specular reflection type smoothness meter, the specular reflection type smoothness of the paper surface measured under the conditions of 20 kg / cm ² pressure, light wavelength of 0.5 μm and measurement time of 100 MS is 9 to 14%. Yes, newspaper.   The newsprint according to claim 1, wherein the amount of used paper pulp derived from used paper is 20% by mass or more of the total amount of pulp.   Recycled paper pulp derived from wastepaper waste paper disintegrates wastepaper raw material containing wastepaper components derived from recycled paper waste as a main component at a disaggregation concentration of 15% or more and a disaggregation temperature of 50 ° C or less, and a viscosity of 2 to 5% of a beating concentration. The newsprint according to claim 1 or 2, which is obtained by refining a shape.   The newsprint according to any one of claims 1 to 3, wherein the water-soluble polymer compound is mainly composed of starch.