JP4020950B1 - Newspaper and its manufacturing method - Google Patents

Abstract

Kind Code: A1 The present invention provides a resource circulation type newsprint paper in which pulp fibers, fillers and pigments are recovered from used paper and used together.
A deinking floss discharged from a used paper processing process as a main material is used as the filler, and the main material is obtained by going through dehydration, drying, firing, and pulverization processes and is adjusted to have a specific composition. A particle aggregate is used at least as a filler for internal addition, the pulp consists of 50 to 100% by weight of waste paper pulp, and the basis weight according to JIS P 8124 is 37 to 48 g / m ² , according to JIS P 8113. Recycled particle-added newsprint paper having a tensile strength in the longitudinal direction measured in conformity with the tensile strength in the transverse direction is at least twice that of the transverse direction, and a surface treatment agent mainly composed of starch is provided on the surface of the paper. It is.
[Selection figure] None

Description

  The present invention relates to newsprint. More specifically, the present invention relates to a resource circulation type newsprint that recovers, recycles, and reuses raw material pulp and filler, which are main components of newsprint, from used paper.

Due to environmental problems in recent years, there has been a movement to collect waste office paper generated from offices throughout the building for the purpose of environmental protection, resource protection, and garbage reduction, and the use of recycled paper using waste paper pulp has been seen. Along with the increase, the ratio of used paper to paper is also increasing.
In addition, from the viewpoints of resource saving, transportation cost reduction, and raw material cost reduction, the weight of each paper is increasing year by year. Furthermore, at the paper mill, the production ratio of recycled paper using recycled paper pulp and the ratio of used paper to paper have increased, and the production speed of the paper manufacturing process has increased further in order to improve paper production efficiency. Yes. Under such circumstances, the demand for newsprint is also progressing in the direction of weight reduction and higher blending of used paper. For example, the weight of newspapers has been reduced in order to increase the number of pages per newspaper without increasing the weight burden at the time of newspaper delivery, the ratio of used paper has been increased in order to deal with environmental problems, The speed of printing presses and the colorization of paper are progressing.
As a result, the newspaper surface color, high-definition, good-quality print finish, double-page spread announcement, etc. can be handled, and the paper surface strength, ink absorbency, print contour and image can be seen through from the opposite side. In addition to the requirements for so-called back-through and concealment, the level of demand for strength such as tensile strength that can withstand high-speed offset rotary printing is increasing. It is an obstacle to high blending.

Conventionally, in order to improve the tensile strength of newsprint, in addition to the reduced pulp strength of recycled pulp and the ash content to be contained, the strength of dampening water used during offset printing is also used in combination with a paper strength enhancer. Attempts have been made to apply a surface treatment agent to suppress the decrease, but since the production cost increased and the opacity decreased, there was a limit to the corresponding means by changing the blending ratio or containing the drug. .
In order to improve the opacity, mechanical pulp has been frequently used as raw material pulp. However, in recent years when high content of used paper pulp is desired, it is difficult to construct newsprint paper as the main raw material. It is. Also, with the widespread use of recycled paper, in recent years, recycled paper that is recycled paper has been further reused, that is, because pulp fibers are repeatedly reused, the resulting recycled paper pulp has fine fibers. Many have reduced strength. The high blending of this waste paper causes a decrease in the strength and opacity of newsprint, lowers the print-through and concealment during printing, and reduces the appearance of the printed surface, such as shading and missing halftone dots. It is expressed.
In order to improve the concealing property of the newsprint as described above and reduce the back-through, it is common to improve the opacity and oil absorption of the paper by using a filler such as white carbon or calcium carbonate. Methods for adding the filler include an external addition in which a filler is surface-coated with a binder and the like, and an internal addition in which the filler is mixed with a pulp raw material to make paper.
Among the fillers, fine filler particles have good light scattering coefficient and absorption coefficient and high opacity improvement effect, but when used as an internal filler, the yield is low, and it is mainly applied by external addition. .
However, when the filler is externally applied, it is necessary to form a coating layer of a certain level or more, so that the weight reduction required for newsprint cannot be achieved. In addition, newsprint web offset presses do not have a drying facility at high speed, so when externally applying fillers, the quality required for newsprint is improved in terms of ink drying, surface strength, plate stains, etc. The problem of not being satisfied arises.

Therefore, for example, a paper containing a pulp and calcium carbonate, a filler internal additive paper (see Patent Document 1) in which hydrated silicic acid is internally added to a specific oil absorption, pore volume, average particle diameter, etc., white carbon and A newsprint (see Patent Document 2) has been proposed in which calcium carbonate is the main component and the proportion of ash is set within a specific range.
In the filler-added paper and newsprint, white carbon is often used as a filler, and therefore, the opacity and oil absorption are certainly improved as compared with the conventional one.
However, when white carbon is used extensively, due to its particle characteristics, there is a problem that it tends to cause a large decrease in paper strength, paper dust generation, and printing equipment contamination. There is also a limit to increasing the amount of addition.

When calcium carbonate is used as a filler, it is generally said that the wear of papermaking wire is fast because its hardness is higher than that of newspaper filler mainly used for acidic papermaking such as kaolin and talc. Similarly, there is concern about plate wear for offset rotary printing during printing.
Patent Document 3 which attempts to use this calcium carbonate for newsprint describes neutral newsprint that contains mechanical pulp and / or deinked waste paper pulp and calcium carbonate and is coated with a clear sizing agent. However, papermaking in the neutral region using calcium carbonate has the problems that the papermaking equipment, especially the wire is subject to wear deterioration, and pitch troubles due to elution of resin components derived from waste paper pulp and wood fibers, and the cause of soiling of the papermaking equipment. In order to express as a problem, when making paper in neutral or alkaline, after adding aluminum sulfate and fixing the resin component contained in the pulp to the fiber, specify calcium carbonate as a filler, in the paper making process It is described that it is necessary to take a complicated operation method in which the resin component is added to the paper while the cationic property of the aluminum sulfate is not lowered after adding as much as possible.
Therefore, it is lightweight and satisfies 120,000 to 180,000 copies per hour in recent years, for example, paper quality strength, ensuring printing workability, printability such as color misalignment, and printing opacity in offset printing using cold set ink. Newspapers suitable for offset rotary printing were not developed.

On the other hand, in paper mills, the yield of fine fibers has increased due to the rapid and forced dehydration at the wire part due to the high blending of waste paper pulp with a lot of fine fibers, the weight reduction of paper, and the speedup of paper machines in recent years. The yield of ash is extremely low, and paper sludge such as drainage and dewatered sludge discharged from each paper making process is increasing.
That is, due to the increase in the production ratio of recycled paper using waste paper pulp and the high blending of waste paper pulp, a lot of waste paper pulp is required, and the amount of waste paper used is increasing. Waste paper such as newspaper and magazine waste paper contains a lot of inorganic substances derived from fillers used in uncoated paper and fillers and pigments used in coated paper. Is separated from the pulp fiber and a large amount of deinking floss containing a large amount of fillers and pigments is generated.
Paper sludges such as deinking floss discharged from waste paper processing processes that contain a large amount of inorganic fillers and pigments, and wastewater and dewatered sludge discharged from each paper manufacturing process have been conventionally burned and reduced in volume. Many have been landfilled.
However, in order to continuously manufacture while maintaining and improving the quality of recycled paper that can contribute to environmental protection, resource protection, and dust reduction by the above-mentioned background technology, the paper mill can recycle and effectively use this paper sludge. Usage is a major issue.

Since the papermaking sludge contains a large amount of inorganic matter, a large amount of combustion ash (inorganic matter) remains even after combustion, and the effect of volume reduction is low. Therefore, efforts such as utilizing this combustion ash as a raw material for cement and soil improvement have been made, but in these methods, combustion ash is used as an auxiliary agent and is not used in large quantities. Most of the combustion ash will be landfilled.
It is conceivable to use the combustion ash as an internal filler for paper, but the combustion ash is not suitable for use as an internal paper filler because it has low whiteness. .
Therefore, a method has been proposed in which combustion ash (incineration ash) is reburned, and the whiteness is improved by slurrying and wet dispersion (see Patent Document 4).
However, in the case of the method of reburning the incinerated ash, in order to completely burn the unburned carbon, it is necessary to set the reburning temperature to 500 to 900 ° C., and the whiteness of the incinerated ash is about 50%. It has been found that it is not suitable for use as a paper filler. It has also been found that when the re-combustion temperature is set to over 900 ° C., the combustion ash (inorganic material) is sintered and melted and becomes extremely hard. In addition, when reburned ash is used as a filler for paper, the reburned ash has very hard properties, so the papermaking wire wears quickly and the life of the papermaking wire becomes very short. Could not be used.
For such papermaking wire wear, it is conceivable that the reburned ash is crushed and its particle size is reduced to reduce wear and improve smoothness, but when used as an internal filler for paper. However, there is a problem that the yield during paper making is low and the reburned ash itself is extremely hard, so that the energy cost for pulverization becomes extremely high.

Also, as a method of using paper sludge, water-containing paper mill waste sludge containing organic matter from paper fibers is supplied into a reactor into which oxygen-containing gas has been injected, and is heated to about 250 to 300 ° C. and 3000 psig (psig). There has been proposed a method of regenerating the inorganic substance in the waste sludge as a papermaking pigment (inorganic filler) by oxidation under pressure for 0.25 to 5 hours (see Patent Document 5).
However, since the method is based on wet air oxidation treatment of papermaking sludge, organic matter removal is not sufficient, the whiteness of the obtained pigment is low, and the particle diameter is not uniform, and the pigment for papermaking (inorganic It is unsuitable for use as a filler, and has a problem that the reaction operation is complicated and expensive.

In addition to these, a method has been proposed in which papermaking sludge is baked into PS charcoal and then incinerated with a kiln to produce white clay as a papermaking raw material (see Patent Document 6).
However, in this method, since the papermaking sludge is fried, not only energy cannot be effectively extracted from the papermaking sludge, but also there is a great demerit that input energy is required. Furthermore, the generated white clay also has a problem that the particle size is uneven and large, and cannot be used as a papermaking filler.

Furthermore, a method for producing a papermaking filler by adding a flocculant to the waste water and granulating the resulting sludge and drying, carbonizing, and firing continuously in a rotary kiln has also been proposed (see Patent Document 7). . In this method, the granulation and shaping are performed prior to firing in order to perform firing uniformly.
However, for example, when a formed sludge having a solid content concentration of 45 to 60% (in other words, a moisture content of 65 to 40%) is continuously dried, carbonized, and calcined in a rotary kiln, regardless of the dry state or carbonized state. First, the treatment of sludge particles is forced to proceed by the rotation of the kiln. Therefore, if the drying is insufficient, a large amount of unburned matter remains inside the particles, and as a result, the firing becomes incomplete and the whiteness is lowered. On the other hand, when overdried, the firing is complete but overfired and the hardness of the obtained regenerated particles is increased. Use of the recycled particles causes a problem that wire wear in a paper machine and cutter blade wear when cutting paper are likely to occur.

The biggest problem of the conventional methods of manufacturing paper fillers and pigments using papermaking sludge as a raw material described in Patent Documents 4 to 7 is that the papermaking sludge used as a raw material flows out through a wire in the papermaking process. What was recovered from wastewater containing solids generated in the washing process in the pulping process, what was separated and recovered in the wastewater treatment process by a solids separator using precipitation or flotation, Various sludges such as those from which foreign substances are removed in the used paper processing process are mixed.
Among the various sludges, for example, a paper strength agent or the like is mixed in sludge that has flowed out through the wire in the papermaking process, and the quality of the sludge varies due to changes in the papermaking process.
Moreover, flocculant is mixed in the sludge collected from the waste water, and the quality of the sludge varies greatly due to papermaking, production volume fluctuations, and in-process washing of the production equipment.
The sludge generated from the washing process in the pulping process contains substances that are not suitable for paper fillers and pigments, and the quality may vary due to fluctuations in chip moisture and pulp production conditions.
Therefore, when various papermaking sludges are used without selection, the quality and quality of the papermaking fillers and pigments are low, and the quality is extremely variable and unstable.

As described above, all of the conventional methods using papermaking sludge all start with the recovery of papermaking particles, and the regenerated particles from the papermaking sludge obtained by these methods have a quality as a papermaking pigment and filler. It was not suitable and lacked quality stability.
Therefore, although raw paper pulp, which is a major component of newsprint, is increasingly used as waste paper pulp, conventional white carbon and calcium carbonate must be used as a filler. In order to protect the environment, conserve resources, and improve the wear problem of papermaking equipment, color printing and high-definition printing can be used to achieve excellent concealment and ink drying properties. The development of technology for obtaining newsprint with excellent halftone dot reproducibility has been awaited.
Japanese Patent Laid-Open No. 09-176985 JP 2002-201590 A JP 09-78491 A JP-A-11-310732 Japanese Examined Patent Publication No. 56-27638 Japanese Patent Laid-Open No. 54-14367 JP 2004-176208 A

The present invention has been made in view of the above-mentioned background art, and provides a resource circulation type newsprint paper that collects and uses pulp fibers and fillers, which are main components of used paper (paper), from used paper. Is an issue.
More specifically, the pulp fibers and fillers, which are the main components of waste paper (paper), are collected together, manufactured at low cost by recycling resources, and further made by making paper in the neutral or alkaline region. Not only is paper strength maintained and there are few paper breaks, it also has sufficient paper quality even when high-speed offset rotary printing is performed, and even if color printing, solid printing, or high-definition printing is performed, it does not show through and conceals. Excellent ink absorbability, good ink drying and halftone dot reproducibility, low blanket stains due to resin and paper dust, printing white spots, etc. It is an object of the present invention to provide a newsprint that can be suitably used for printing in high-speed offset rotary printing.

The present invention that has solved this problem is as follows.
[Invention of Claim 1]
Newspaper with internal filler in pulp,
The main material is deinked floss discharged from the waste paper treatment process as the filler, and the main raw material is obtained through dehydration, drying, firing and pulverization processes, and is aggregated in the firing process, and calcium and silicon are contained in the particles. And a regenerated particle aggregate containing three components of aluminum is used as the filler for internal addition,
The pulp comprises 50-100% by weight of waste paper pulp,
The ash content according to JIS P 8251 is 2% to 20%,
The basis weight according to JIS P 8124 is 37 to 48 g / m ² ,
The tensile strength in the longitudinal direction in accordance with JIS P 8113 has at least twice the tensile strength in the transverse direction,
The surface of the paper is provided with a surface treatment agent mainly composed of starch.
Recycled particle-attached newsprint.

[Invention of Claim 2]
Newspaper with internal filler in pulp,
The main material is deinked floss discharged from the waste paper treatment process as the filler, and the main raw material is obtained through a dehydration, drying, firing and pulverization process, and is aggregated in the firing process, so that calcium and silicon are contained in the particles. And silica-coated regenerated particles in which the surface of a regenerated particle aggregate containing three components of aluminum is coated with silica is used as the filler for internal addition,
The pulp comprises 50-100% by weight of waste paper pulp,
The ash content according to JIS P 8251 is 2% to 20%,
The basis weight according to JIS P 8124 is 37 to 48 g / m ² ,
The tensile strength in the longitudinal direction in accordance with JIS P 8113 has at least twice the tensile strength in the transverse direction,
The surface of the paper is provided with a surface treatment agent mainly composed of starch.
A newsprint with silica-coated regenerated particles internally added.

[Invention of Claim 3]
10 seconds Kobusaizu degree based on JIS P 8140 is 30~300g / m ^2, playback particles internally added newsprint of claim 1, wherein.

[Invention of Claim 4]
Renewed particle-added newsprint according to claim 1 or 3 , wherein the oil absorption based on JIS P 3001 is 50 to 150 seconds.

[Invention of Claim 5]
A method for obtaining newsprint with a filler added to pulp,
Deinked floss discharged from the used paper processing process as the filler is used as a main raw material, and the main raw material is obtained by going through dehydration, drying, firing and pulverization processes, and is aggregated in the firing process, so that calcium and silicon are contained in the particles. And a regenerated particle aggregate containing three components of aluminum and the filler for internal addition,
The pulp comprises 50-100% by weight of waste paper pulp,
After paper making, flatten with a soft calender consisting of an elastic roll and a metal roll,
The ash content according to JIS P 8251 is 2% to 20%,
The basis weight according to JIS P 8124 is 37 to 48 g / m ² ,
A newsprint is obtained in which the tensile strength in the longitudinal direction in accordance with JIS P 8113 is at least twice the tensile strength in the transverse direction.
A method for producing recycled particle-added newsprint.

The newsprint paper of the present invention uses deinked floss that has been incinerated or landfilled as industrial waste as a filler material for papermaking, and uses recycled paper pulp made from wastepaper as the main raw material pulp, thereby recycling resources And can be manufactured at low cost.
Moreover, in recent years, 120,000 to 180,000 copies per hour, for example, ensuring the paper quality strength and printing workability in offset printing using cold-set ink, high ash yield at the time of paper making, and paper making equipment such as wire wear Printing equipment stains due to wear deterioration and resin component elution hardly occur, excellent paper strength is maintained and there are few paper breaks, as well as less printing plate stains due to paper dust, printing white spots, etc., and ink Newspaper paper that has excellent absorbability, excellent opacity, and little show-through can be suitably used for high-speed offset rotary printing, offset rotary color printing, and high-definition printing.

Next, an embodiment of the present invention will be described.
The newsprint of this embodiment is obtained by using deinking floss discharged from the waste paper processing step as the filler as a main raw material, and the main raw material is obtained through a dehydration, drying, firing and pulverization step, and agglomerated in the firing step. A regenerated particle aggregate containing three components of calcium, silicon, and aluminum in the particles is used as the filler for internal addition, and the pulp consists of 50 to 100% by mass of waste paper pulp, and an ash content in accordance with JIS P 8251 Is 2% to 20%, the basis weight according to JIS P 8124 is 37 to 48 g / m ² , and the tensile strength in the longitudinal direction according to JIS P 8113 is more than twice the tensile strength in the lateral direction. The surface of the paper is provided with a surface treatment agent mainly composed of starch.
The regenerated particle aggregate agglomerated in the firing step contains calcium, silicon and aluminum as constituents in a mass ratio of 30 to 82: 9 to 35: 9 to 35 in terms of oxide, and the regenerated particles It is desirable that the aggregate is a regenerated particle aggregate in which the total content of calcium, silicon, and aluminum is 90% by mass or more in the regenerated particle aggregate component.

First, raw material pulp will be described. The raw material pulp is made up of 50 to 100% by mass of used paper pulp made from used paper such as newspaper waste paper, magazine waste paper, imitation / colored waste paper, and OA waste paper. Since waste paper pulp is blended in an amount of 50% by mass or more in this way, it greatly contributes to effective use of resources, and cost reduction can be achieved.
There is no limitation in particular in the kind of used paper pulp, For example, a diinking pulp (DIP), a waist pulp (WP) etc. are mention | raise | lifted, These can be used individually or simultaneously.

As the raw material pulp, pulp used for ordinary paper can be used as appropriate in addition to the waste paper pulp. Examples of raw material pulp other than waste paper pulp include Stone Grand Pulp (SGP), Pressurized Stone Grand Pulp (PGW), Refiner Grand Pulp (RGP), Chemi Grand Pulp (CGP), Thermo Grand Pulp (TGP), and ground wood. Pulp (GP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), refiner mechanical pulp (RMP) and other mechanical pulp; softwood kraft pulp (NBKP), hardwood kraft pulp (LBKP) and other chemical pulp; The pulp etc. which bleached these are mention | raise | lifted and it can select and use 1 type (s) or 2 or more types from these.
As described above, the ratio of the waste paper pulp in the raw material pulp is 50 to 100% by mass. However, 60 to 100% by mass, particularly 70 to 100% by mass, is achieved from the point of realizing resource saving and cost reduction. It can be 100 mass%.

Next, the filler will be described. The filler of the present invention is obtained by using deinked floss as a main raw material and through a dehydration step, a drying step, a firing step, and a pulverization step. Furthermore, as will be described later, a deinking floss aggregation process, a granulation process, a classification process provided between the processes, and the like may be performed. 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.
Regenerated particle aggregates containing specific amounts of calcium, silicon and aluminum obtained by firing in the firing step are used as fillers.
The regenerated particle agglomerates using deinking floss as a main raw material mainly use deinking floss generated in a deinking treatment process for producing waste paper pulp from waste paper. Particularly, deinking floss discharged in the recycling process of waste 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. And in the used paper recycling process, since the used paper itself is selected in advance, the deinking floss has a stable composition over time of its inorganic matter, and thus the composition of the resulting recycled particle aggregate is also stable. Become. These deinking froths contain calcium carbonate, kaolin, talc, titanium dioxide, silica, alumina and the like as inorganic substances.

For further dehydration of the deinking floss, known dehydration means can be used as appropriate. In one example of the present embodiment, the deinking floss is dehydrated by separating water from the deinking floss by a screen serving as a dewatering unit. In the screen, the deinking floss dehydrated to 90% to 97% is preferably sent to, for example, a screw press and further dehydrated to 50% or less.
If the moisture content exceeds 50%, the temperature of the drying / combustion process in the first combustion furnace is lowered, energy loss due to heating increases, and uneven combustion of the raw material tends to occur, thereby promoting uniform combustion. I want to. Further, there are problems that the moisture in the exhaust gas to be discharged increases, the recombustion treatment efficiency is reduced in dioxin countermeasures, and the load on the exhaust gas treatment facility is increased. In addition, although lowering the moisture content of the raw material facilitates uniform combustion, dehydrating the moisture content of the raw material to less than 25% increases the size of the dehydration equipment and significantly increases the dehydration energy. Have the problem.

The dehydrated product is dried in advance. As the drying means, known drying means such as hot air drying can be used, but hot air drying means which can be loosened while drying the deinking floss and further can be classified by specific gravity can be most preferably used.
Specific examples of hot air drying means that can be suitably used include dewatering deinking floss with a loosening facility such as an impeller, while loosening so that the volume average particle diameter is about 250 to 3000 μm, preferably about 355 to 2000 μm, Hot air is blown by hot air blowing means provided below the impeller equipment to perform hot air drying. 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 deinked floss that has been dried, classification by a cyclone can be employed.

The deinked floss that has been dried and classified is sent to the firing process.
For firing, for example, a commonly used firing furnace such as a rotary kiln, fluidized bed furnace, floating furnace, stoker furnace or the like can be used, and particularly preferably, a combustion / firing method by indirect heating using a hot air furnace or an electric furnace is performed. Temperature control and fine adjustment of firing degree are easy. For example, in firing using a rotary kiln, combustion treatment can be carried out either alone or in combination with firing by direct heating or indirect overheating, and primary firing is direct heating kiln furnace, secondary firing is indirect heating kiln furnace In particular, a method of firing with an externally heated electric furnace in which the firing temperature can be easily adjusted can be employed.

The firing temperature burns ink pigments such as carbon black in sludge and organic compounds such as fibers and polymers, and agglomerates them in the firing step so that the regenerated particle aggregate contains 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.
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 a substance with high hardness, for example, baking at a temperature of 500 ° C. or less is considered. However, under such conditions, it is difficult to completely burn the organic compound, and it is useful for papermaking. It is not possible to obtain a silica-coated regenerated particle aggregate having a possible level of whiteness.
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, and alumina contained in the deinking floss progresses and the hardness is increased. In addition, it is not preferable because a large amount of energy and time may be required to pulverize the regenerated particle aggregate mainly composed of deinked floss to the desired particle size in the present invention. Therefore, as firing conditions, primary firing is preferably performed at 510 to 750 ° C., secondary firing is preferably performed at 500 to 700 ° C., primary firing is performed at 520 to 650 ° C., and secondary firing is performed at 500 to 600 ° C. More preferably.

The firing process can be performed in one step, but is preferably at least two steps, and more preferably at least two steps by continuous equipment. If the firing process is composed of at least two stages of firing, firing unevenness is less likely to occur during firing by burning organic matter, and firing can be performed evenly. In particular, by varying the physical means in the firing step, it is possible to avoid uneven firing and improve the firing rate.
The firing temperature has a great influence on the whiteness and hardness of the regenerated particle aggregate to be produced. If the primary firing temperature is less than 510 ° C., the remaining amount of unburned material is large and the regenerated particle aggregate formation is insufficient. And the whiteness of the obtained regenerated particle aggregate does not reach 70% or more. On the other hand, when the primary firing temperature exceeds 750 ° C., most of the calcium carbonate contained in the deinking floss is thermally decomposed, and many substances causing high pH such as calcium oxide and calcium silicate are generated which are difficult to use as resources. In addition, there is a possibility that the obtained regenerated particle aggregate is melted by heat and is extremely hard and has poor wire wear. On the other hand, when the secondary firing temperature is less than 500 ° C., the organic matter is not sufficiently combusted, or the combustion is uneven, and the whiteness of the produced regenerated particle aggregate is not increased. On the other hand, if the secondary calcination exceeds 700 ° C., the problem is that the surface of the carbonized and calcined regenerated particle aggregates is melted by being exposed to a high temperature to form a very hard melt, Oxygen is unlikely to reach the core of the regenerated particle aggregate due to combustion due to composting, and there is concern over occurrence of uneven combustion and unburned sites. Moreover, by making the temperature of the secondary firing 10-50 ° C. lower than the temperature of the primary firing, the unburned matter can be burned while preventing overfire of the surface of the regenerated particle aggregate.
Of course, the temperature of the secondary firing can be the same as the temperature of the primary firing, and in the case of the same temperature, if the temperature is 520 to 600 ° C., the firing can be slowly reduced to reduce the unburned matter, and the white A regenerated particle aggregate having a degree of at least 70% or more, preferably more than 80% 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 in the firing furnace.

In the firing step, the oxygen concentration in the process is 0.05% or more, preferably from 0.05 to at least one of means for blowing air into the process and means for exhausting air from the process. 20%, more preferably 5 to 15% at the upper end in the primary firing furnace, more preferably 7 to 13%, and 10 to 20% in the vicinity of the burner of the secondary firing furnace, more preferably 12 to 18%. . When the oxygen concentration in the primary firing furnace is less than 0.05%, firing does not proceed and not only uneven firing proceeds, but also enormous time and energy costs are required for firing. On the other hand, when the oxygen concentration in the secondary firing furnace exceeds 20%, overheating tends to occur, and the regenerated particle aggregates turn yellow due to overheating unevenness. Oxidation may progress and it may be difficult to use as a paper filler. In the present embodiment, the moisture content of the dried and classified deinked floss (dried material) supplied to the firing step is adjusted to at least 2 to 20%, more preferably 5 to 15% by mass. Therefore, when the oxygen concentration in the firing step is 0.05 to 20%, firing can be performed very efficiently, firing can be performed within 90 minutes, and extremely high productivity can be obtained. . For example, baking can be performed in about 60 minutes by setting the moisture content of the dried product to 10% by mass.
In this regard, oxygen in the firing process is consumed by a burner or the like for firing, and the oxygen concentration decreases. However, the oxygen concentration can be maintained and adjusted by blowing or exhausting an oxygen-containing gas such as air. In addition, by blowing or exhausting oxygen-containing gas, the temperature in the firing step can be finely adjusted, and the regenerated particle aggregate can be uniformly fired uniformly.

Firing in the primary firing furnace is desirably performed so that the unburned rate becomes 5 to 30% by mass. It is more preferable to carry out so that it may become 8-25 mass%, and it is especially preferable to carry out so that it may become 10-20 mass%. If the unburned ratio in the primary firing is less than 5 mass percent, the particle surface is overfired in the firing and the surface becomes hard, the internal oxygen is deficient, and the whiteness of the regenerated particle aggregate decreases. . On the other hand, when the unburned ratio in primary firing exceeds 30% by mass, unburned matter remains even after subsequent burning and firing, the unburned matter is hardened by over-burning due to self-burning, unburned matter In order to prevent the remaining of the particles, the particles are burned and fired until the particle surface is overfired, and the regenerated particle aggregate surface becomes hard.
In the recycled particle agglomerate production facility, it is preferable to remove in advance foreign matters other than the raw material of the regenerated particles. It is preferable in terms of removal efficiency to remove foreign matters such as sand, plastic, and metal. In particular, the iron content is preferably removed by avoiding the mixing of iron content, since it causes the whiteness of the regenerated particles to be reduced due to oxidation. Therefore, each process is designed or lined with materials other than iron to prevent iron from being mixed into the system due to wear, etc., and a high magnetic material such as a magnet is installed in the drying / classifying equipment, etc. In particular, it is preferable to remove iron.

In the present embodiment, particles having a particle size of 40 μm or less are 80% by mass or more, more preferably 90% or more in advance before the pulverization step in the drying step, firing step, and classification step as necessary. It is preferable to treat it in advance. 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.
The particle size of the regenerated particle aggregate according to the present invention is 0.05 μm or more, more preferably 0.3 μm or more, in terms of yield in raw pulp and prevention of loss of regenerated particle aggregate into white water. The average particle diameter is preferably 10 μm or less, and more preferably 8 μm or less, from the viewpoint of maintaining proper printing and preventing clogging of the blade tip.
Furthermore, by adjusting calcium, silicon, and aluminum in the deinking floss as a raw material in advance to a mass ratio described below, for example, the pore volume of the regenerated particle aggregate is 0.15 to 0.60 cc / g, fine. The pore surface area can be 10 to 25 m ² / g, the pore radius can be 30 to 100 nm, and a regenerated particle aggregate excellent in oil absorption and opacity can be obtained.

In order to make the particle size of the regenerated particle aggregate uniform in each step, classification is preferably performed, and the quality can be further stabilized by feeding back coarse particles and fine particles to the previous step.
In addition, it is preferable to granulate the deinked floss that has been dehydrated in the previous stage of the drying process, and more preferably to classify the granulated product uniformly so that coarse or fine particles are formed. The quality can be further stabilized by feeding back the grains to the previous process. In granulation, ordinary granulation equipment can be used, and equipment such as a rotary type, a stirring type, and an extrusion type is preferable.

One of the great features of the newsprint of the present invention is that at least the regenerated particle aggregate is used as a filler, and a specific amount is internally added to raw pulp containing 50 to 100% by weight of waste paper pulp.
Since this recycled particle aggregate can be recycled by firing deinked floss, it does not require disposal such as landfill as waste, greatly reducing environmental burden and saving resources. It contributes. In addition, since the raw material is deinked floss generated in the waste paper processing step, there is an advantage that it is inexpensive, the amount of new regenerated particle aggregate used can be suppressed, and the manufacturing cost is sufficiently reduced. Furthermore, by using the regenerated particle aggregate, the yield of ash during paper making is high. Unlike calcium carbonate, for example, there is no wear deterioration of paper making equipment such as wire wear, and the resin component is regenerated in a fine state. By adsorbing to particle agglomerates, pitch troubles due to resin agglomeration can be prevented, printing equipment can be hardly contaminated, paper can be manufactured at low cost with high operability, and superior to the previous level. Opacity and paper strength are imparted to the paper, and there are fewer breakthroughs and paper breaks.
The regenerated particle aggregate thus obtained contains calcium, silicon and aluminum. The ratio of these calcium, silicon, and aluminum in the regenerated particle aggregate is subjected to elemental analysis using an X-ray microanalyzer (model number: E-MAX S-2150, Hitachi, Ltd./Horiba, Ltd.). In terms of oxide, calcium: silicon: aluminum is 30 to 82: 9 to 35: 9 to 35, further 40 to 82: 9 to 30: 9 to 30, particularly 60 to 82: 9 to 20: 9 to 20 The mass ratio is preferably. At the same time, the total content in terms of oxides in the elemental analysis of calcium, silicon and aluminum is 85% by mass or more, preferably 90% by mass or more.

Further, as a suitable regenerated particle aggregate internally added to the raw material pulp in this embodiment, a silica-coated regenerated particle aggregate in which the surface of the particle obtained through the above-described steps is coated with silica is particularly preferably used. Can do.
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 aggregates are added and dispersed in an alkali silicate solution, and after preparing a slurry, while heating and stirring, an acid is added while maintaining the liquid temperature at about 70 to 100 ° C. to produce 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 8-13. 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. The surface of the regenerated particle aggregate is caused by the bond between the silica sol fine particle on the surface of the inorganic fine particle and the silicon, calcium, or aluminum included in the regenerated particle aggregate accompanying the crystal growth of the silica sol fine particle. Silica can be deposited on the substrate. 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 to a range of 8 to 13. 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 decreases and the silica content (SiO _{2) in the} solution does not become difficult to 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 hindered. In order to eliminate the possibility that the effect of improving the fixability will be insufficient, the silicic acid content (in terms of SiO ₂ ) is preferably 10% by mass or less.

The silica-coated regenerated particle aggregate in which the regenerated particle aggregate surface is coated with silica is obtained by measuring the volume distribution average particle diameter using a particle size distribution analyzer (Microtrac particle size analyzer: Nikkiso Co., Ltd.). Is preferably adjusted to 0.1 to 10 μm with a known pulverizer such as a wet pulverizer, the ratio of the average particle diameter of 0.1 to 10 μm is at least 80% and the ratio of 20 μm or more is 0.5%. It is more preferable to make it below. Moreover, the oil absorption property by the silica coating effect and opacity can be improved by making calcium, silicon, and aluminum into the mass ratio of 10-80: 10-80: 5-29 in conversion of an oxide.
By using silica-coated recycled particle agglomerates, it is possible to react with sodium hydroxide and contribute to the recycling of recycled paper agglomerates as a buffering agent and bleaching aid in the used paper processing process for recycling. Can do. Further, when such a silica-coated regenerated particle aggregate is internally added to the raw material pulp as a filler, the whiteness of the paper, opacity, surface strength, and more than when using a regenerated particle aggregate not coated with silica, Effects such as ink drying properties, ink absorption unevenness, and bulkiness can be further improved.

  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 regenerated particle agglomerates with a high calcium content are added internally to the raw material pulp, the opacity of the paper may be slightly reduced, but the silica-coated regenerated particle agglomerates with silica precipitated on the surface are used for papermaking. The regenerated particle aggregate has a very high function, and the opacity of the paper obtained by internally adding the silica-coated regenerated particle aggregate to the raw material pulp is remarkably improved.

In particular, when the regenerated particle aggregate is a silica-coated regenerated particle aggregate, the ratio of these calcium, silicon and aluminum is 10 to 80: It is preferable that it is a mass ratio of 10-80: 5-29. At the same time, the total content in terms of oxides in the elemental analysis of calcium, silicon and aluminum is 85% by mass or more, preferably 90% by mass or more.
Thus, for example, in the regenerated particle aggregate, calcium is contained in an amount of 30% by mass or more in terms of oxide, and in the silica-coated regenerated particle agglomerate, the regenerated particle aggregate in which the amount is 10% by mass or more in terms of oxide is used as a raw material. When added internally to the pulp, the whiteness of the resulting paper can be particularly improved.

In order to adjust the ratio of calcium, silicon, and aluminum in the regenerated particle aggregate within the above range, for example, in terms of oxide, it is originally preferable to adjust the raw material composition in the deinking floss, but the drying step and the firing step Further, if necessary, in the classification step, it is also possible to employ a method in which a coating floss having a clear origin or an adjustment step floss is contained by spraying or a method in which incinerator scrubber lime is contained.
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 newsprint manufacturing with a large amount added as an opacity improver for silicon adjustment For the adjustment of aluminum, a papermaking wastewater sludge using an acid papermaking system or other sulfuric acid band or a high quality papermaking process wastewater sludge using a large amount of clay can be used as appropriate.

Furthermore, since the regenerated particle aggregate used in the present embodiment has a flexible and porous property in which fine particles are aggregated, it contributes to the formation of a bulky paper layer, and the regenerated particle aggregate is internally added to the raw material pulp as a filler. The newsprint obtained in this way has a high filler yield, a low density, and a good stiffness.
When the content of the regenerated particle aggregate is too small, for example, in a calendar process on a paper machine, a smoothing effect is hardly exhibited, and the opacity after printing is lowered due to a decrease in paper opacity. Or the rigidity of the newsprint is increased, and the running performance on a rotary press may be reduced. Therefore, the content is preferably 2% by mass or more, more preferably 5% by mass or more based on the raw material pulp. . Conversely, if the content of regenerated particle aggregates is too high, it is desirable in terms of surface properties and rigidity, but ash tends to fall off during transport in the printing press, resulting in reduced surface strength, Since there is a possibility that fluffing, printing white spots, and paper dust may occur, the content is preferably 20% by mass or less, more preferably 15% by mass or less, based on the raw material pulp.

In the present embodiment, the regenerated particle aggregate can be used alone as a filler, but in addition to this, calcium carbonate such as heavy calcium carbonate and light calcium carbonate, talc, etc. And at least one filler selected from clays such as kaolin clay and delaminated clay, inorganic fillers such as titanium dioxide, synthetic silica and aluminum hydroxide, and synthetic polymer fine particles such as polystyrene resin and urea formaldehyde resin You can also
In addition, as additives to be added to the paper slurry obtained from raw pulp and filler, those added to ordinary paper can be used, such as starches, vegetable gums, aqueous cellulose derivatives, sodium silicate, etc. Paper strength enhancers: rosin, starch, CMC (carboxyl methylcellulose), polyvinyl alcohol, alkyl ketene dimer, ASA (alkenyl succinic anhydride), neutral rosin and other internal sizing agents; polyacrylamide and copolymers thereof, silica Examples thereof include a yield improving agent such as sodium acid.

Furthermore, after preparing a paper stock slurry from raw pulp and making paper, a surface treatment agent containing at least starch as a main component is provided on the surface. As an example of starch, modified starch can be used, and in addition, a surface treatment agent containing a polymer material such as PVA (polyvinyl alcohol) or polyacrylamide as a component can be applied in combination.
The starch that can be suitably used in the surface treatment agent is not particularly limited, but modified starches such as carboxymethyl starch (anionic), hydroxyalkyl starch (nonionic), and phosphate starch (anionic) penetrate into paper. However, although it has the effect of improving the tensile strength and surface strength, it exhibits neutrality or anionicity, so it is inferior in fixability to the surface of an anionic pulp fiber and has low coating properties. Therefore, it is preferable that it is a cationic starch having high fixability to the pulp fiber surface exhibiting anionic property.
Cationic starch is a starch in which a primary amino group, a secondary amino group, a tertiary amino group, a quaternary ammonium base, and a cationic group such as a tertiary amino group and a halogenated alkyl group are added. Alternatively, amphoteric starch having an anionic group introduced in addition to the cationic group may be used. The degree of substitution of the cationic group is preferably about 0.005 to 0.05. When the degree of substitution is less than 0.005, the water absorption resistance is lowered, and it is very difficult to introduce a large amount of cationic groups exceeding 0.05. Although the kind of raw material starch is not specifically limited, general industrial starches such as tapioca, corn, potato, waxy maize can be used, and tapioca is particularly preferable. When the starch is cationic, the fixability to pulp fibers is improved, the coating property is excellent, and the surface strength is also improved.

Furthermore, the starch according to the present invention is more preferably an esterified starch. In the case of esterified starch, the ink density and ink setting properties are dramatically improved. The raw material starch for esterification includes various starch-containing materials in addition to untreated starch and treated starch. As such, for example, wheat starch, potato starch, corn starch, sweet potato starch, tapioca starch, sago starch, rice starch, waxy corn starch, high amylose content corn starch and other untreated starch, wheat flour, tapioca starch, Examples include starch-containing materials such as corn flour and rice flour, and those obtained by oxidizing and acid-treating these starches and starch-containing materials. Among these, tapioca starch is preferable because the ester-modified product is superior to other cereal starches in terms of viscosity, film property, elasticity, and extensibility. In the esterified starch, the degree of esterification is not particularly limited, but is the average number of ester bonds introduced and is 1 to 3, preferably 1 to 2, per glucose unit. Of the esterified starches, hydroxyesterified starch is preferred. This can be easily and inexpensively obtained by subjecting the raw starch to an oxidation treatment and reducing the carboxymethyl group to a hydroxyethyl group. Most preferably, a hydrophobic group-containing ester-modified tapioca starch in which a hydrophobic group is introduced into the terminal group of the ester-modified starch can be used.
More preferably, the esterified starch to be used has a carboxylic acid (—COOH) structure in the terminal group, and in the neutral region, ionization like —COO 2 ⁻ cannot secure a bond due to hydrogen bonding, resulting in repulsion. Because ester-modified starch that exhibits thixotropic behavior due to its properties exhibits fluidity during coating, it does not easily penetrate into the base paper after application to the base paper surface, and exhibits high film properties on the base paper surface. In addition, it is preferable that a binder resin for polyvinyl alcohol having a high film property is contained. The esterified starch is particularly preferably 1-octenyl succinic esterified starch obtained by esterifying and modifying tapioca starch as a main raw material. 1-Octenyl succinate esterified starch is particularly excellent in terms of viscosity, film elasticity, and coatability, and in combination with polyvinyl alcohol, it is intended to further improve coatability, ink density, and ink setability. Can do.

As the surface treatment agent, other adhesives as appropriate, for example, latexes such as styrene-butadiene copolymer, polyvinyl alcohol and polyacrylamide, and pigments such as kaolin and calcium carbonate, antifoaming agents, water-proofing agents, surface size, etc. Various auxiliaries such as agents and preservatives can also be added. Moreover, the solid content concentration of the surface treatment agent is not particularly limited, and is preferably adjusted to, for example, about 2 to 25% by mass according to the coating apparatus and the coating amount.
A particularly suitable surface treating agent used in combination with starch is polyvinyl alcohol.
When coated with polyvinyl alcohol alone as a surface treatment agent, it exhibits almost three times the surface strength compared to when coated with starch alone and is excellent in coating properties, but has high coating properties. In the case of printing ink that is dried by the permeation of the solvent into the paper, such as mold ink, the absorbability of the printing ink solvent is poor, and the ink setting speed of the ink is inferior. In addition, when a certain amount of polyvinyl alcohol is applied alone, the viscosity of the coating solution is high, and the film transfer method cannot be used due to problems such as paper breakage, papermaking equipment contamination, wrinkles, and paper surface contamination. . Therefore, when used together with starch, while promoting the penetration of an appropriate ink solvent into the paper, the ink pigment component is retained on the paper surface, the coating property is improved, and the ink setting property is also prevented from being lowered. The kind of polyvinyl alcohol is not particularly limited. The polyvinyl alcohol includes, in addition to ordinary polyvinyl alcohol obtained by hydrolyzing polyvinyl acetate, modified polyvinyl alcohol such as polyvinyl alcohol having a terminal cation-modified or anion-modified polyvinyl alcohol having an anionic group.

As the polyvinyl alcohol, those having an average degree of polymerization of 500 to 3500 are preferably used, and in particular, those having an average degree of polymerization of 1000 to 2400, and more preferably in the range of 1700 to 2400 are excellent in compatibility with starch. Since it becomes easy to obtain a good film property, it is preferably used. Further, it is preferably polyvinyl alcohol having a saponification degree of 80 or more and close to 100, and is preferably completely saponified polyvinyl alcohol having a saponification degree of 90 or more and 100. When it is completely saponified polyvinyl alcohol, it becomes easier to obtain a coating property having water resistance and heat resistance on the paper surface than when it is partially saponified polyvinyl alcohol.
In addition, by using such polyvinyl alcohol, starch and polyvinyl alcohol can be blended in a short time with good affinity with starch, improving operability and generating mist in the coating equipment. Can be reduced. By using polyvinyl alcohol having a high degree of saponification and a high degree of polymerization, it is possible to realize a high offset ink setting property while obtaining a high ink concentration. In addition, it is preferable that even if the sheets are stacked after printing on the paper, ink transfer to the back surface can be prevented.

  If the surface treatment agent is used in an excessively large amount, not only the cost is increased, but also the adhesiveness of the paper surface called “Nepari” property tends to be expressed when the paper surface is wet. If this sharpness increases, there is a risk that blanket piling, especially in non-image areas, will increase and the paper surface will stick to the blanket during printing, resulting in running problems such as wrinkles and paper breaks. Because there is, it is not preferable. Further, when the amount of the surface treatment agent used is increased, the transparency of the target paper may be increased, that is, the opacity may be decreased, or the ink drying property may be deteriorated. Of these surface treatments, starch and polyacrylamide are widely used because of their relatively low nepariness, but they are both highly soluble in water, so that they can be easily eluted in dampening water during printing. At the same time, it is deposited on the blanket, and blanket piling is likely to occur. Also, the eluted surface treatment agent is transferred to and accumulated on the printing plate via the blanket, so that the non-image area of the printing plate becomes sensitized, and ink stains on the non-image area, that is, paper contamination called background contamination, is induced. Therefore, it is not preferable to use a large amount.

As a result of the synergistic effect of providing the surface treatment agent on newsprint with internally added recycled particle aggregates, it is possible to suppress generation of paper dust and ink absorption unevenness by using waste paper pulp as raw material pulp, and ink It is possible to further improve the printability such as improvement in setability and halftone dot reproducibility.
The surface treatment agent is a coating apparatus commonly used in the papermaking field, such as a size press, a blade metering size press, a rod metalling size press, a gate roll coater, a blade coater, a bar coater, a rod coater, an air knife coater, etc. And apply.
The coating amount of the surface treatment agent is preferably adjusted so that the dry weight on one side is 0.4 g / m ² or more in order to sufficiently improve the surface strength of the paper. to prevent or cause a decrease in and ink drying property, so that the 3.0 g / m ² or less on one surface dry weight mass, more preferably adjusted to below 0.7 to 2.5 g / m ² It is preferable to do.

Thus, the stock prepared from the stock slurry and, if necessary, the additive can be made by a known paper machine, and further passed through a calender device as necessary, followed by pressurization and smoothing treatment. Can be finished into newspaper.
As the calender device, from a machine calendar by a combination of metal rolls, a metal roll, and a roll imparted with elasticity such as a roll covered with a highly durable resin material such as a woolen paper roll or a polyamide resin. A so-called soft calendar is known, and a machine calendar using a combination of a metal roll and a metal roll is generally used.
However, if smoothening is achieved by increasing the nip pressure in the calendar process or increasing the number of nips, the ink fillability will increase, but the bulkiness of the paper will be impaired. In addition to causing this, the opacity after printing is lowered and the rigidity is lowered.
On the other hand, if the calendar process is reduced, a bulky paper can be obtained, but the difference in front and back of the paper surface is increased. There arises a problem that the density of the image is significantly different between the back side and the back side. This is because the dehydration conditions in the wire part and press part are slightly different between the front and back sides during the paper making process, so there is a difference in the smoothness of the paper, and the distribution of filler and fine fibers in the thickness direction. It is considered that there is a difference between the front and the back of the ink transferability.
In particular, in recent years, with the colorization and weight reduction of newsprint, there has been a further demand for good ink fillability and high opacity after printing. In the present invention, a soft calender is preferably used.

When a machine calendar is used in a suitable combination with newspapers internally containing recycled particle aggregates as a filler, there is a tendency to promote the difference between the smoothness and the smoothness that occurs in the process up to drying before applying the surface treatment agent. On the other hand, when combined with a soft calendar, density unevenness after calendering due to uneven formation of the paper layer can be reduced, and as a result, printing with a uniform density without ink absorption unevenness when color printing is performed during offset printing. A surface can be obtained, especially in combination with the regenerated particle aggregate, and the unevenness is reduced so that the surface of the paper is flattened with a high-temperature iron without increasing the density with the regenerated particle aggregate that originally has cushioning properties. The soft calender makes the regenerated particle aggregates easily entangled with the fibril fibers of the raw pulp, improving the flatness and denseness of the paper surface without increasing the density. A decrease in paper strength difficult Kitashi. In addition, as a means for improving ink fillability, it is possible to smooth newspaper paper by flattening with a soft calender or the like as described above, and to smooth the paper layer without strongly pressing, It is more preferable to use a soft calender because a decrease in paper layer strength can be sufficiently suppressed.
On the other hand, it is desirable that the hardness of the elastic roll of the soft calender is 87 to 95 ° in Shore hardness according to JIS Z 2246. If it is less than 87 °, the durability of the elastic roll is poor and sufficient smoothness cannot be obtained. On the other hand, if it exceeds 95 °, there is a problem that it is difficult to obtain a uniform profile. As for the roughness of the elastic roll, it is particularly desirable that the maximum value of the surface roughness according to JIS B 6001 is less than 0.5 μm in order to reduce ink unevenness on the paper surface.
Moreover, in order to smooth the surface which touches the metal roll of the soft calender, the surface temperature of the metal roll is set to 40 to 150 ° C, preferably 80 to 140 ° C, and more preferably 90 to 120 ° C. By setting the surface temperature within this range, even in multi-color printing in which slight density unevenness affects, a printing surface with a uniform density can be made without any difference between the front and the back.
In the use of the soft calendar, the flatness and bulkiness can be further improved by passing the paper so that the back side that contacts the wire side of the newsprint is in contact with the metal roll surface of the soft calendar first, In high-speed papermaking at 1500 m / min or more, it is possible to obtain newsprint with high flatness and little difference in front and back in color printing.
More preferably, by increasing the coating amount of the surface treatment agent provided on the front and back sides on the back side from the front side, better flatness and bulkiness can be obtained, and it is possible to obtain a newsprint with a waist.

The newsprint thus obtained has an ash content of 2 to 20% in accordance with JIS P 8251, and hot water measured in accordance with “Test method for pH of paper, paperboard and pulp-water extract” described in JIS P 8133. The extraction pH is preferably 6.0 or more, more preferably pH 6.1 or more, and is preferably pH 9.5 or less, more preferably pH 8.5 or less. When the hot water extraction pH is in such a range, calcium carbonate, which is considered to be an auxiliary use, or a little, but it is considered that the elution of calcium carbonate contained in the regenerated particle aggregate is prevented, and regenerated particles are used. The shape of the aggregate is stable, the formation of calcium hydroxide is prevented, the occurrence of dirt and scale in the papermaking process system is suppressed, paper deterioration can be suppressed, and resource circulation can be achieved. In addition, the ink drying property of paper can be improved, the ink absorption unevenness can be reduced, the deterioration can be sufficiently suppressed, and the storage stability and the fixing property of the auxiliary agent can be further improved.
The pH of the newsprint at the time of papermaking is determined by adding aluminum sulfate (sulfuric acid band) and fixing the resin component to the fiber through aluminum or forming an aggregate of the resin component. In order to prevent adhesion of the resin component in the manufacturing process by incorporating it into the paper support, it is common to make newsprint within the range of pH 4 to less than 6 where the cationicity of the aluminum ion species is most active, The waste paper pulp used in the present invention is manufactured by deinking from waste paper, so that the pH is as high as 6 or more, and the use of calcium carbonate, which is considered to be auxiliary use in terms of stability and pH adjustment due to high pH. At this time, the calcium carbonate dissolves to eliminate the risk of yield loss and the cause of soiling in the papermaking process. In than paper, because the improvement in paper strength is achieved by paper at pH6 or higher, it is preferable to adjust such that the order of 6 to 9.5.

  Addition of the regenerated particle agglomerates can be performed at any stage of the prior art, but is preferably performed between the raw material blending chest and the inlet. Addition during this time makes it easy to disperse the regenerated particle aggregates, improving the fixability to pulp fibers, and as a result, improving the yield of the filler. Further, since the regenerated particle aggregate does not inhibit the binding between the pulp fibers, the rigidity of the paper is not lowered. In order to disperse the regenerated particle aggregate more uniformly and to improve the fixability to the pulp fiber, it is particularly preferable to add the regenerated particle aggregate as close as possible to the inlet.

Further, the basis weight of the paper according to the present invention is measured in accordance with the “basis weight measurement method” described in JIS P 8124 from the viewpoint of weight reduction, for example, ensuring the paper quality strength in high-speed rotary printing and ensuring the printing opacity. Then, it is preferably 37 g / m ² or more, more preferably 40 g / m ² or more, and from the viewpoint of weight reduction, the basis weight is 48 g / m ² or less, and further 46 g / m ² or less. preferable. If it is less than 37 g / m ² , for example, it is difficult to ensure the strength in a high-speed offset rotary printing press, and if it exceeds 48 g / m ² , it goes against the recent weight saving and resource saving.
The whiteness of the paper varies depending on the application, but in order to prevent eye strain of subscribers in newsprint, it conforms to the “Testing Method for Hunter Whiteness of Paper and Pulp” described in JIS P 8123. Measured at least 50% or more, and the whiteness is preferably 52 to 60%, more preferably 52 to 59%.
Newspaper paper opacity is required to have high opacity because it is difficult to see through during printing, but it is measured according to the “Paper Opacity Test Method” described in JIS P 8138. And 85.0% to 95.0%, more preferably 87.0 to 93.0%.
Further, the density of newsprint is measured in accordance with “Paper and paperboard—Test method of thickness and density” described in JIS P 8118 from the viewpoint of maintaining the strength accompanying weight reduction and weight reduction in recent years. It is preferably 50 to 0.80 g / cm ³ , more preferably 0.55 to 0.75 g / cm ³ .
In addition, the stiffness in the MD direction of the paper is measured in accordance with “a stiffness test method using a paper Clark stiffness tester” described in JIS P 8143, for example, in order to give a waist suitable for high-speed rotary printing. It is preferable that it is 30-55 cm < ³ > / 100, Furthermore, it is 32-50 cm < ³ > / 100.

Offset rotary printing used in newsprint is a method in which dampening water and printing ink are supplied to a printing plate, then the ink is transferred to a rubber plate called a blanket, and then transferred to paper for printing. Compared to the conventional letterpress printing method, ink with relatively high viscosity is used, so that the ink does not penetrate into the paper layer, the ink is well-positioned, and there is little ink penetration after printing. It has the advantage (high opacity).
The present inventors consist of 50 to 100% by weight of waste paper pulp based on the present invention, and oxidize calcium, silicon and aluminum obtained through a dehydration step, a drying step, a firing step and a pulverization step as at least the filler. A regenerated particle aggregate containing at a mass ratio of 30 to 82: 9 to 35: 9 to 35 in terms of product and having a total content ratio of the calcium, the silicon and the aluminum of 90% by mass or more is used. In the transfer of dampening water and printing ink on newsprint having a basis weight of 37 to 48 g / m ² according to JIS P 8124, the 10-second bump size degree based on JIS P 8140 of the newsprint is 30 to 300 g / It has been found that it is preferable that the relationship is m ² and the oil absorption based on JIS P 3001 is 50 to 150 seconds. . By suppressing the relationship between so-called hydrophilicity and oleophilicity within a predetermined range, it becomes possible to improve the offset rotary printing suitability in combination with the flattening treatment.

Furthermore, considering the paper quality strength in high-speed rotary printing, the surface strength of the paper is preferably at least grade 3 or higher as measured by an RI tester (manufactured by Akira Seisakusho Co., Ltd.) described later.
Furthermore, in the present invention, the tensile strength in the longitudinal direction in accordance with JIS P 8113 is at least twice the tensile strength in the transverse direction, more preferably at least 2.4 times, and even more preferably at least 2.6 times. It is characterized by being.
More specifically, it is preferable that the longitudinal tensile strength is 2.4 KN / m or more and the transverse tensile strength is 0.9 KN / m or more.

The regenerated particle aggregate used in the present invention contains calcium, silicon and aluminum as constituent elements in terms of oxides, and calcium: silicon: aluminum is 30 to 82: 9 to 35: 9 to 35, and further 40 to 82: 9-30: 9-30, especially 60-82: 9-20: 9-20, and when the regenerated particle aggregate is a silica-coated regenerated particle aggregate, calcium, silicon And aluminum in a mass ratio of 10 to 80:10 to 80: 5 to 29 in terms of oxide, and at the same time, the total content in terms of oxide in the elemental analysis of these calcium, silicon and aluminum is: 85% by mass or more, preferably 90% by mass or more, more preferably 93% or more, and the reason is not clear, but in the firing step Because it has an agglomerate structure exhibiting irregular porosity due to the collection, the agglomerate structure is well entangled with the raw material pulp that constitutes newsprint, and is contained in the paper layer without reducing the bonding force between the fibers. The tensile strength in the longitudinal direction in accordance with JIS P 8113 is considered to be excellent because of the excellent ionic bond strength between the raw material pulp and calcium, silicon and aluminum constituting the regenerated particle aggregate. It is possible to ensure at least twice the tensile strength in the direction.
In newsprint, in particular, as mentioned above, offset rotary printing using 120,000 to 180,000 copies per hour, such as cold set ink, is becoming mainstream. Is an extremely important issue, and it is preferable for the operation of the rotary press to ensure that the tensile strength in the longitudinal direction is at least twice the tensile strength in the transverse direction.

  As described above, the newsprint according to the present embodiment is mainly composed of deinked floss generated in the used paper processing step in raw material pulp containing 50% by mass or more of used paper pulp, and a total of 85 masses of calcium, silicon and aluminum. % Of the regenerated particle agglomerates also contained as a filler. Therefore, the newsprint according to the present embodiment has a high ash yield at the time of papermaking, and is produced at low cost by reusing resources without causing wear deterioration of the papermaking equipment such as wire wear and printing equipment contamination. Excellent paper strength is maintained and there is no paper breakage, and there is no blanket stains due to paper dust, clogging of the sword, color misalignment, etc. In addition, the newsprint according to the present embodiment is excellent in various characteristics at the time of printing, particularly at the time of color printing, and can be suitably used for high speed offset rotary color printing such as about 1 to 180,000 copies / hour.

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.
[Production of regenerated particle aggregates (Production Examples (Examples) 1 to 20 and Comparative Production Examples 1 to 10), commercially available newsprint (commercial products) 1 to 2]
As shown in Table 1, deinking floss, papermaking sludge, a mixture of deinking floss and papermaking sludge, a commercially available filler, and agglomerates by cross-linking adsorption of a commercially available filler are used as raw materials. After going through the steps, the drying step and the firing step, a wet pulverization treatment was performed to obtain a regenerated particle aggregate. In addition, deinking floss means what was separated from pulp fiber in the deinking process to remove ink adhering to the used paper in the used paper processing process for producing deinked pulp from used paper, and the papermaking sludge is the papermaking sludge The sludge separated in the clarifier in the wastewater treatment process of the factory was used.
Furthermore, in Production Examples 3, 5, 19, and 20, the regenerated particle aggregates were added to and dispersed in a sodium silicate solution (water glass) to prepare a slurry, and then the liquid temperature under the conditions shown in the table while stirring with heating. In this state, dilute sulfuric acid was added to form a silica sol. Next, the pH of the reaction solution was adjusted to the conditions shown in the table, and silica was deposited on the surface of the regenerated particle aggregate to obtain a silica-coated regenerated particle aggregate.
With respect to the obtained regenerated particle aggregate and the silica-coated regenerated particles after silica coating, the contents of calcium, silicon and aluminum were determined in terms of oxides, respectively, and the total content of calcium, silicon and aluminum was calculated. The results are shown in the table. The average particle size is also shown in the table. Furthermore, the wire wear degree, productivity, quality stability and appearance were also examined. These results are also shown in Table 2.

In addition, the various measured values shown in Table 1 and Table 2 were measured by the following methods.
(A) After the dehydration process and the raw material moisture content of the dried product A sample was collected, and the moisture content was measured using a drier in accordance with the moisture test method described in JIS P 8127.
(A) The proportion of particles having a particle size of 355 to 2000 μm after the drying step (firing step inlet) is the same as the mass ratio of the dried particles having a particle size of more than 2000 μm. Then, the mass ratio of the dried particles having a particle diameter of less than 355 μm was measured, and the mass ratio was calculated.
(C) Oxygen concentration in the firing process Measured with a gas analyzer (model: PG250 type) manufactured by Horiba.
(D) Content of calcium, silicon and aluminum in regenerated particle aggregate (as oxide) X-ray microanalyzer (model number: E-MAX S-2150, manufactured by Hitachi, Ltd./Horiba, Ltd.) Elemental analysis in terms of oxide and mass ratio measurement of elements were performed.
(E) Average particle diameter of regenerated particle aggregate 10 mg of the regenerated particle aggregate sample was added to 8 mL of a methanol solution and dispersed for 3 minutes with an ultrasonic disperser (output: 80 W). The average particle size of this solution was measured with a particle size distribution measuring device (Laser Microtrac Particle Size Analyzer: manufactured by Nikkiso Co., Ltd.).
(F) Whiteness of regenerated particles The whiteness was measured with a whiteness meter KR-III manufactured by Kumagaya Riki Kogyo Co., Ltd. in accordance with US TAPPI standard method T-646os75.
(G) Degree of wire wear Using a wear degree test apparatus (manufactured by Nippon Filcon Co., Ltd.), the degree of wear of the plastic wire was measured for 3 hours at a slurry concentration of 2% by mass.
(H) 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.
(I) Quality stability For each item of whiteness, particle size, and production volume at a fixed time interval, the degree of fluctuation was measured, ranked in the order of the smallest fluctuation, and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: Up to the top 10 o: 11-22, Δ: 23-25, x: 26 or less (co) Appearance The color of the regenerated particle aggregate was visually observed and classified into white and gray.

  From the results shown in Table 2, it can be seen that the regenerated particle aggregates of Production Examples 1 to 20 each have a low degree of wire wear and excellent productivity and quality stability. On the other hand, it can be seen that the regenerated particle aggregates of Comparative Production Examples 1 to 4 all have a high degree of wire wear and are inferior in productivity and quality stability.

[Manufacture of Newspaper (Production Examples 1-20 and Comparative Examples 1-10)]
In the ratio shown in Table 3, deinking pulp (DIP), pressurized stone ground pulp (PGW) and softwood kraft pulp (NBKP) were blended, and the freeness was 120 mL with a refiner. S. A pulp slurry adjusted to F (based on JIS P 8121) was obtained. To this pulp slurry, 0.5 part by mass of cationized starch is added per 100 parts by mass of absolutely dry pulp, and the regenerated particle aggregates obtained in Production Examples 1 to 20 and Comparative Production Examples 1 to 10 are used as fillers. The aggregate was added so as to have an ash content shown in Table 4, and after adjusting the pH with a sulfuric acid band, newspaper paper having the basis weight shown in the table was made with a twin wire paper machine. Furthermore, a surface treatment agent having the conditions shown in Table 3 was provided, and a planarization treatment was performed using a soft calender.
Various physical properties of the obtained newspaper were examined. These results are shown in Tables 3 and 4. Moreover, commercial newsprint was prepared as commercial products 1 and 2, and various physical properties were examined in the same manner as the newsprints of Examples 1 to 20 and Comparative Examples 1 to 10. The results are shown in Tables 3 and 4.

In addition, the various measured values shown in Table 3 and Table 4 were measured by the following methods.
(A) Basis weight It measured based on the "basis weight measuring method" as described in JISP8124.
(B) Paper thickness and density It measured based on "Paper and board-Test method of thickness and density" described in JIS P8118.
(C) Quantification of surface treatment agent (quantification method of starch and polyvinyl alcohol in surface treatment agent treated paper using starch and polyvinyl alcohol)
(1) Take a certain amount of measurement paper (about 1 or 2 A4 plates: sample area or weight is precisely weighed) and cut out to about 1 cm ² . This is heated and dissolved under stirring with water to completely loosen the paper fibers.
(2) No. Filter through 1 filter paper. Concentrate the extract. The filtration residue is heated and dissolved again by adding water and filtered. In standard work, this operation is repeated 6 to 7 times. Actually, about 90% is eluted in one operation, and it is considered that about 99% is extracted by repeating three times, and is often completed in about three times. Concentrate the total extract to about 100 ml.
(3) Add about 10 ml of concentrated hydrochloric acid to all the above extract, heat for 2 to 3 hours (80 to 90 ° C.) and leave overnight. Here, if a precipitate is formed, it is removed by filtration (No. 5A filter paper). Since about 100 ml of distilled water is used for precipitation washing, the final volume is about 200 ml of filtrate (the amount of liquid here is precisely weighed).
(4) The filtrate obtained in (3) is divided into two, and starch and PVA are quantified according to the following methods.
PVA quantification method (formalization method) Performed in a 300 ml beaker.
(5) About 10 to 15 ml of a commercial formalin aqueous solution is added to the extract, and a precipitate is completely generated by heating at 80 to 90 ° C. or more for 1 to 2 hours.
(6) Filtered with a filter paper (No. 5A) that has been dried and precisely weighed in advance, and repeatedly washed with water or warm water until no acidic reaction is observed (usually washed with 500 to 800 ml of hot water) To do).
(7) The filter paper to which the precipitate is attached is dried and weighed, and the amount of PVA is calculated from the obtained weight of the precipitate by the following formula.
PVA (g) = precipitate weight (g) × 0.95 (0.95 is a weight increase correction coefficient in formalization)
Starch quantification method (Rayeinon method) Performed in a 300 ml Erlenmeyer flask.
-Reagent adjustment-
Liquid A 34.62 g of crystalline copper sulfate is dissolved in water to make a total volume of 500 ml.
Liquid B Potassium sodium tartrate: 173 g, NaOH: 50 g are dissolved in water to make a total volume of 500 ml.
Solution C 1 g of methylene blue is dissolved in water to make 100 ml.
(8) Add 3 to 4 drops of phenolphthalein indicator to the extract and prepare it to be slightly red with NaOH granules, concentrated hydrochloric acid, and 1N NaOH (sample solution).
(9) Equivalent amounts of liquid A and liquid B are mixed (adjusting the failing liquid), and one drop of liquid C is dropped into 1 to 5 cc (often 1 cc) of this liquid. A certain amount (for example, 5 cc) of the sample liquid neutralized in (8) and 20 cc of distilled water are mixed there. Heat in an open flame.
(10) If the blue color disappears and becomes slightly red at 15 seconds after foaming, the end point is reached. If the end point is not reached, add the sample amount of (8) and search for the sample amount that the blue color disappears and becomes slightly red 15 seconds after heating and foaming (heating is limited to within 3 minutes after the start of foaming). Because it becomes difficult to confirm the end point.)
(11) The amount of starch (converted sugar) is calculated from the sample, the total sample solution, and the amount of the failing solution by the following formula.
Starch amount (g) = Fering liquid titer × Fering liquid consumption (ml)
Example) Falling fluid titer: 0.0046, Falling fluid consumption: 1 ml, Sample volume: 5 + 5 + 1 = 11 ml, Total sample volume: 262 × 2 = 524 ml (Here, consider the case where the extract is divided into two, 2 times). In this case, the amount of starch in the extract (g) = 0.22 (g). Here, the first size paper area, in the case of 0.12 m ^2, the starch coating weight = 1.8g / m ^2. Note that the Fering liquid titer is measured separately.
(Reference) Measuring method of Fering fluid titer.
[1] 0.7 g of oxidized starch is dissolved in 200 ml of distilled water.
[2] Add 10 ml of concentrated hydrochloric acid.
[3] Add 300 ml of distilled water.
[4] Using 5 ml of the liquid obtained in [3], titrate according to the above (8) to (11). Using the above formula, the Fering fluid titer is determined.
(D) Arithmetic mean surface roughness (Ra)
The arithmetic average surface roughness was measured according to the arithmetic surface roughness defined in JIS B 0601.
(E) White paper opacity This is a value measured according to JIS P 8149.
(F) Whiteness A value measured according to JIS P 8212.
(G) Cobb sizing degree This is the sizing degree at a measurement time of 10 seconds in accordance with JIS P 8140.
(H) Stiffness (longitudinal direction)
It is a value measured according to JIS P 8143.
(I) Tensile strength (vertical / horizontal)
It is a value measured according to JIS P 8113.
(J) Surface strength It printed on the surface of the paper sample by RI tester (made by Akira Seisakusho) using ink tack 6 (made by Toyo Ink Manufacturing Co., Ltd.). The state where the fibers per 10 cm ² were peeled off was visually observed and evaluated based on the following evaluation criteria (grade).
(Evaluation criteria)
1: There is considerable peeling of the fiber 2: There is peeling of the fiber 3: Some peeling of the fiber 4: Little peeling of the fiber 5: Almost no peeling of the fiber Surface strength (k) Standing The surface of the newsprint was repeatedly surface-treated 5 times with the rubber roll not applied with the test ink. Using a loupe, the surface of the paper web was visually observed in the range of 100 mm × 100 mm, and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: Very little standing
○: Little standing.
(Triangle | delta): There is a little bit of standing.
×: There are very many standing spots.
(L) Ink absorption unevenness Using an offset color printing machine (model number: SYSTEM C-20, manufactured by Komori Corporation), four-color printing was performed in the order of indigo, red, yellow, and black. The ink density unevenness of the deep blue / red color portion was visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: Ink density unevenness is not recognized at all, and the image is uniform and clear.
○: Ink density unevenness is hardly recognized, and the image is uniform.
Δ: Ink density unevenness is recognized and the image is slightly non-uniform.
X: Ink density unevenness is obvious and the image is non-uniform.
(M) Paper powder accumulation on the blanket
(1) Using an offset color printer (model number: SYSTEM C-20, manufactured by Komori Corporation), four-color printing was performed in the order of indigo, red, yellow, and black at the same printing speed. After printing 10,000 copies, the degree of paper powder accumulation on the blanket non-image area was visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: Generation of paper dust is not recognized.
○: Slight generation of paper dust is observed, but there is no practical problem.
Δ: The occurrence of paper dust is clearly recognized.
X: A lot of paper dust is accumulated on the blanket, and the blanket is white.
(2) Using an offset rotary press (Toshiba offset rotary press, manufactured by Toshiba Corporation), black monochrome printing was performed at a printing speed of 900 rpm. After printing 120,000 copies, the paper dust accumulated on the blanket was scraped off, and the mass was measured and expressed as the mass per 100 cm ^{2 of} paper. The film thickness of the fountain solution was 0.9 μm.
(N) Oil Absorption Degree According to “Oil Absorbance Test Method” described in JIS P 3001-1976, measured by light oil No. 1.
(O) Ash content Measured according to “Paper, paperboard and pulp-ash content test method” described in JIS P 8251.
(P) Hot water extraction pH
It was measured according to “Test method for pH of paper, paperboard and pulp-water extract” described in JIS P 8133.
(Q) Opacity after printing After printing with respect to the backside reflectance before printing when the offset rotary printing press changes the ink amount of the ink (black) for offset rotary printing and the printed surface reflectance is 9%. The ratio of the back surface reflectance was obtained. The reflectance is a value measured by a spectral whiteness colorimeter (manufactured by Suga Test Instruments Co., Ltd.).
(R) Printing white void Using an offset color printing machine (model number: SYSTEM C-20, manufactured by Komori Corporation), monochrome printing of ink (black) for offset rotary printing with a dot area ratio of 30 to 100%. went. About a solid part with a halftone dot area ratio of 100%, the degree of white spots on the printed surface was visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: Almost no white spots are observed.
○: Little white spots are observed.
Δ: White spots are observed.
X: White spots are remarkable.
(S) Nepparity After two newspaper paper samples were cut to an appropriate size and immersed in water for 10 seconds, the two sheets were quickly brought into close contact and passed through a calendar at a linear pressure of 100 kg / cm. After drying at room temperature for 24 hours, the peel strength of the two sheets was measured using a tensile tester (model number: Autograph AGS-500NG, manufactured by Shimadzu Corporation). In addition, the larger the numerical value, the higher the Nepari property (adhesiveness).
(T) Ink drying property Using an offset rotary press (Toshiba offset rotary press, manufactured by Toshiba Corporation), printing speed of 900 rpm, ink for newspaper printing with a vegetable oil content of 45%, indigo, red, yellow, Four-color printing was performed in the order of black. Overlap the 500 copies of the printed material so that the printed surface and the white paper surface overlap, and leave it for 1 day under a load of 24.5 kPa, then visually observe the degree of dirt on the white paper surface and evaluate based on the following evaluation criteria did.
(Evaluation criteria)
(Double-circle): Dirt is hardly recognized.
○: Only a small amount of dirt is observed.
Δ: Dirt is observed.
X: Dirt is remarkable.
(U) Number of paper breaks Using an offset rotary press (Toshiba offset rotary press, manufactured by Toshiba Corporation), black ink is printed at a printing speed of 900 rpm, and paper breaks occur during 120,000 copies. The number of times was measured.
(V) Back-through Using an offset rotary press (Toshiba offset rotary press, manufactured by Toshiba Corporation), black monochrome printing was performed at a printing speed of 900 rpm. After printing 120,000 copies, the black solid surface was visually observed from the back side and evaluated based on the following evaluation criteria.
(Evaluation criteria)
A: Almost no see-through is observed.
○: Only a small amount of strikethrough is recognized.
(Triangle | delta): See-through is recognized.
X: The showthrough is remarkable.

From the above results, the newsprints of Production Examples 1 to 20 contain calcium, silicon and aluminum in an amount of 85% by mass or more, and the deinked floss is made of recycled particle aggregates as raw materials, and used paper pulp is in an amount of 50% by mass or more. Since it is made by adding paper to the raw material pulp that contains it, not only can it be obtained at low cost by recycling resources, but it also has an appropriate basis weight, density and hot water extraction pH, whiteness, stiffness and surface strength. It can also be seen that it has both excellent opacity and paper strength. In addition, the newspapers of these production examples 1 to 20 have no or little flaking, ink absorption unevenness, accumulation of paper dust on the blanket, and no paper breakage, and high opacity after printing, and print white spots and showthrough. It can be seen that it has characteristics that are very suitable for, for example, high speed web offset printing because there is little or no.
On the other hand, the newsprint of Comparative Production Example 5 is not deinked floss, but a regenerated particle aggregate made from paper sludge as a raw material, and the amount of waste paper pulp used as a raw material pulp is small. Therefore, resource saving and cost reduction are not achieved, and in addition to eruption, ink absorption unevenness, paper powder accumulation on the blanket, paper breakage, most of the opacity after printing, printing whiteout and back-through It turns out that it has a characteristic suitable for high-speed offset printing by a bad result.
In addition, newsprint papers using commercially available fillings of Comparative Production Examples 1 to 4 are also printed in addition to the flaking, ink absorption unevenness, accumulation of paper dust on blankets, and paper breakage, as compared with Production Examples 1 to 20. As a result, most of the opacity, printing white-out and back-through are bad, and it can be seen that the present invention has characteristics suitable for high speed, color and high-definition rotary printing.

  The newsprint of the present invention can be used as newsprint particularly suitable for high-speed offset color printing in, for example, satellite-type or tower press-type offset color printing machines.

Claims (5)

Newspaper with internal filler in pulp,
The main material is deinked floss discharged from the waste paper treatment process as the filler, and the main raw material is obtained through dehydration, drying, firing and pulverization processes, and is aggregated in the firing process, and calcium and silicon are contained in the particles. And a regenerated particle aggregate containing three components of aluminum is used as the filler for internal addition,
The pulp comprises 50-100% by weight of waste paper pulp,
The ash content according to JIS P 8251 is 2% to 20%,
The basis weight according to JIS P 8124 is 37 to 48 g / m ² ,
The tensile strength in the longitudinal direction in accordance with JIS P 8113 has at least twice the tensile strength in the transverse direction,
The surface of the paper is provided with a surface treatment agent mainly composed of starch.
Recycled particle-attached newsprint. Newspaper with internal filler in pulp,
The main material is deinked floss discharged from the waste paper treatment process as the filler, and the main raw material is obtained through a dehydration, drying, firing and pulverization process, and is aggregated in the firing process, so that calcium and silicon are contained in the particles. And silica-coated regenerated particles in which the surface of a regenerated particle aggregate containing three components of aluminum is coated with silica is used as the filler for internal addition,
The pulp comprises 50-100% by weight of waste paper pulp,
The ash content according to JIS P 8251 is 2% to 20%,
The basis weight according to JIS P 8124 is 37 to 48 g / m ² ,
The tensile strength in the longitudinal direction in accordance with JIS P 8113 has at least twice the tensile strength in the transverse direction,
The surface of the paper is provided with a surface treatment agent mainly composed of starch.
A newsprint with silica-coated regenerated particles internally added. 10 seconds Kobusaizu degree based on JIS P 8140 is 30~300g / m ^2, playback particles internally added newsprint of claim 1, wherein. Renewed particle-added newsprint according to claim 1 or 3 , wherein the oil absorption based on JIS P 3001 is 50 to 150 seconds. A method for obtaining newsprint with a filler added to pulp,
Deinked floss discharged from the used paper processing process as the filler is used as a main raw material, and the main raw material is obtained by going through dehydration, drying, firing and pulverization processes, and is aggregated in the firing process, so that calcium and silicon are contained in the particles. And a regenerated particle aggregate containing three components of aluminum and the filler for internal addition,
The pulp comprises 50-100% by weight of waste paper pulp,
After paper making, flatten with a soft calender consisting of an elastic roll and a metal roll,
The ash content according to JIS P 8251 is 2% to 20%,
The basis weight according to JIS P 8124 is 37 to 48 g / m ² ,
A newsprint is obtained in which the tensile strength in the longitudinal direction in accordance with JIS P 8113 is at least twice the tensile strength in the transverse direction.
A method for producing recycled particle-added newsprint.