JP2008156774A - Paper for book and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a paper for a book, obtained by reutilizing a resource and adding a loading material into the inside, and to provide a method for producing the same. <P>SOLUTION: The paper for the book containing the loading material added into a pulp is obtained by internally adding a reclaimed particle aggregate obtained by using a deinked froth discharged from a waste paper-treating process as a main raw material, and passing the main raw material through a dehydration step, a drying step, a firing step and a pulverizing step, to the inside as the loading material. In the firing step, the reclaimed particle aggregates aggregated so as to contain three components of calcium, silicon and aluminum in a particle, and the paper has a flexibility index of ≤2.9, which is represented by the formula: B=(S×10<SP>5</SP>)/T<SP>3</SP>[wherein, B is a flexibility index; S is a transverse Clark stiffness (cm<SP>3</SP>/100) measured based on JIS P 8143; T is the thickness (μm) of paper]. The method for producing the paper is also provided. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to book paper and a method for manufacturing the same. More specifically, the present invention relates to a book paper having a flexibility and flatness, and a method for producing the book paper at low cost, with a filler reusing resources from a used paper processing step being internally added and maintaining bulkiness.

  Book paper is usually required to be bulky (low density) in addition to its flexibility and flatness because of its use. In general, calcium carbonate is added to the raw material pulp in order to give the book paper flexibility and flatness. However, if the amount of calcium carbonate added is too large, the bulkiness is lost. Therefore, there is a limit in making book paper compatible with both flexibility and flatness and bulkiness by using calcium carbonate.

  In view of this, various research and developments have been made on techniques for achieving both suppleness, flatness and bulkiness in book paper without using calcium carbonate. Many of them are technologies that simultaneously add suppleness and bulkiness by adding chemicals consisting of surfactants such as paper thickness improvers and softeners to raw pulp, or blend mechanical pulp as raw pulp to increase bulkiness. It is a technology to get.

  As a technique for adding the chemicals to the raw material pulp, for example, in Patent Document 1, a bulky softener is used, and it is manufactured by drying so that the paper surface temperature is equal to or higher than the melting point of the bulky softener during the preheating drying period. A bulky flexible paper is disclosed. Patent Document 2 discloses a bulky printing paper in which 50% or more of the total inter-fiber binding inhibitor is present up to 30 μm from both surfaces, and containing starch and sizing agent as necessary. ing.

  However, when a chemical such as a bulky softener or an all-fiber bond inhibitor is internally added to the raw material pulp as in the bulky flexible paper described in Patent Document 1 or the bulky printing paper described in Patent Document 2, the size press part The applicator roll is damaged, and for example, the surface paper strength agent starch is uncoated. In addition, the cost increases by adding such chemicals.

  On the other hand, as a technique for blending mechanical pulp as raw pulp, for example, Patent Document 3 discloses that 65 to 95% by weight of all pulp components is mechanical pulp, and 20 to 80% by weight of mechanical pulp components is pine. A bulky offset printing medium paper composed of a thermo-mechanical pulp of a material system is disclosed. Patent Document 4 discloses a bulky medium-sized printing paper in which a starch-based paper strength agent is coated on the surface of a base paper obtained from a stock containing at least one hardwood mechanical pulp and a bulking agent. .

However, when mechanical pulp is blended as pulp, such as the bulky offset printing medium described in Patent Document 3 and the bulky medium printing paper described in Patent Document 4, the smoothness of the paper surface is remarkably increased. In order to maintain smoothness, surface calendering is necessary. However, when the surface is calendered in this way, there arises a problem that a sufficient bulky effect cannot be obtained this time.
JP 2002-155495 A JP 2004-115986 A JP-A-5-98593 JP 2005-163253 A

  The present invention has been made in view of the above-described background art, and solves the problems when a specific chemical is blended, when mechanical pulp is used as a raw material pulp, or when calcium carbonate is internally added as a filler. The present invention provides a book paper that combines flexibility and flatness while maintaining bulkiness, and provides a method that can realize the recycling and can easily manufacture such book paper at low cost. For the purpose.

That is, the present invention
(I) Book paper in which a filler is internally added to pulp,
Deinking floss discharged from the waste paper treatment process is used as the main raw material, and the main raw material is obtained through a dehydration process, a drying process, a firing process and a pulverization process. In the firing process, the three components of calcium, silicon and aluminum are contained in the particles. Regenerated particle aggregates aggregated so as to contain at least internally added as the filler,
The following formula (1):
B = (S × 10 ⁵ ) / T ³ (1)
(here,
B: supple index,
S: JIS P 8143 horizontal Clark stiffness was measured according to (cm ^3/10
0),
T: Paper thickness (μm)
Is)
It is related with a book paper characterized by the supple index represented by 2.9 being 2.9 or less.

The present invention also provides
(Ii) a book paper in which a filler is internally added to pulp,
Deinking floss discharged from the waste paper treatment process is used as the main raw material, and the main raw material is obtained through a dehydration process, a drying process, a firing process and a pulverization process. In the firing process, the three components of calcium, silicon and aluminum are contained in the particles. The silica-coated regenerated particle aggregate in which silica is further precipitated is added at least internally as the filler on the surface of the regenerated particle aggregate that has been aggregated to contain
The following formula (1):
B = (S × 10 ⁵ ) / T ³ (1)
(here,
B: supple index,
S: JIS P 8143 horizontal Clark stiffness was measured according to (cm ^3/10
0),
T: Paper thickness (μm)
Is)
It is related with a book paper characterized by the supple index represented by 2.9 being 2.9 or less.

The present invention also provides
(Iii) A book paper manufacturing method for making paper by adding a filler to pulp,
Deinking floss discharged from the used paper processing process is the main raw material, and the main raw material is subjected to a dehydration process, a drying process, a baking process, and a pulverization process. In the baking process, the particles contain three components: calcium, silicon, and aluminum. Agglomerated to prepare regenerated particle aggregates,
As the filler, at least the regenerated particle aggregate is internally added to the pulp,
The following formula (1):
B = (S × 10 ⁵ ) / T ³ (1)
(here,
B: supple index,
S: JIS P 8143 horizontal Clark stiffness was measured according to (cm ^3/10
0),
T: Paper thickness (μm)
Is)
It is related with the manufacturing method of the book paper whose supple index represented by these is 2.9 or less.

Furthermore, the present invention provides
(Iv) A book paper manufacturing method in which a paper is internally added with a filler,
Deinking floss discharged from the used paper processing process is the main raw material, and the main raw material is subjected to a dehydration process, a drying process, a baking process, and a pulverization process. In the baking process, the particles contain three components: calcium, silicon, and aluminum. A regenerated particle aggregate is prepared by agglomeration as described above, and silica is further precipitated on the surface of the regenerated particle aggregate to prepare a silica-coated regenerated particle aggregate.
As the filler, at least the silica-coated regenerated particle aggregate is internally added to the pulp,
The following formula (1):
B = (S × 10 ⁵ ) / T ³ (1)
(here,
B: supple index,
S: JIS P 8143 horizontal Clark stiffness was measured according to (cm ^3/10
0),
T: Paper thickness (μm)
Is)
It is related with the manufacturing method of the book paper whose supple index represented by these is 2.9 or less.

  The book paper of the present invention has a flexibility and flatness while maintaining its bulkiness, since a filler that reuses resources from the used paper processing process is internally added. Further, by the manufacturing method of the present invention, resource recycling is realized, and book paper having excellent characteristics as described above can be easily manufactured at low cost.

  As described above, the book paper of the present invention has a filler internally added to the pulp, and the filler is a deinking floss discharged from the used paper processing step as a main raw material, and the main raw material is used in a dehydration step and a drying step. At least a specific regenerated particle aggregate obtained by agglomeration so that the three components of calcium, silicon, and aluminum are contained in the particle is obtained through the firing step and the pulverization step.

  First, the pulp used in the present invention will be described. The type of the pulp is not particularly limited. For example, hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), softwood unbleached kraft pulp (NUKP), hardwood semi-bleached kraft Pulp (LSBKP), softwood semi-bleached kraft pulp (NSBKP), hardwood sulfite pulp, softwood sulfite pulp and other chemical pulp; Stone Grand Pulp (SGP), Pressurized Stone Grand Pulp (PGW), Refiner Grand Pulp (RGP), Thermo Mechanical pulp such as Grand Pulp (TGP), Chemi Grand Pulp (CGP), Crushed Wood Pulp (GP), Thermomechanical Pulp (TMP), etc .; used tea paper, craft envelope waste paper, magazine waste paper, newspaper waste paper, leaflet waste paper, office waste paper, cardboard Old paper, old white paper, old Kent , Waste paper pulp manufactured from imitation waste paper, old paper waste paper, etc., waste paper pulp such as disaggregation / deinking waste paper pulp, disaggregation / deinking / bleaching waste paper pulp; chemically from non-wood fibers such as kenaf, hemp, straw Or well-known various pulps, such as a pulp manufactured mechanically, are mention | raise | lifted, From these, 1 type (s) or 2 or more types can be selected suitably, and can be used.

  In the present invention, as will be described later, since a specific regenerated particle aggregate is at least internally added as a filler, even if mechanical pulp is used as the pulp, a conventional general filler is added internally. Furthermore, the smoothness of the paper surface is not significantly reduced. However, if too much such mechanical pulp is blended, the smoothness and tensile strength of the resulting book paper may decrease, so the blending amount of the mechanical pulp is adjusted to 50% by mass or less of the total amount of pulp. It is preferable.

  Next, the filler blended in the pulp will be described. In the present invention, at least a specific regenerated particle aggregate is used as the filler, and the specific regenerated particle aggregate is a deinking floss discharged from a used paper processing step as a main raw material, and the main raw material is a dehydration step. It is obtained through a drying step, a firing step, and a pulverization step, and in the firing step, the particles are aggregated so that the three components of calcium, silicon, and aluminum are contained therein.

  As described above, in the present invention, one of the major features is that the specific regenerated particle aggregate is internally added to the pulp as at least a filler, and the specific regenerated particle aggregate is internally added as a filler. As a result, the problems associated with the conventional addition of calcium carbonate are solved, and the resulting book paper has both flexibility and flatness while maintaining its bulkiness.

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

  The main raw material of the regenerated particle aggregate is deinking floss generated in a deinking process for producing used paper pulp from used paper. In particular, deinking floss discharged in the recycling process of used paper is preferable because it is made of a material derived from papermaking raw materials and contains less impurities such as iron and other heavy metals. In the used paper recycling process, the used paper itself is selected in advance, so that the deinking floss has a stable inorganic composition over time, and the resulting recycled particle aggregate has a stable composition. These deinking froths contain, for example, calcium carbonate, kaolin, talc, titanium dioxide, silica, alumina and the like as inorganic substances. In the present invention, such deinking floss is used as the main raw material of the regenerated particle aggregate. The proportion of deinking floss in all raw materials is preferably 50% by mass or more, more preferably 60% by mass or more as a solid content.

  Usually, the deinking floss has a moisture content of about 95 to 98% by mass, and a floc is formed by adding a flocculant to perform dehydration. Such dehydration treatment can be carried out in one or more stages, but solidifying the floc can cause uneven firing in the subsequent firing step. The moisture content is preferably dehydrated to 40 to 70% by mass. If the moisture content is less than 45% by mass, the dehydration energy cost increases. On the other hand, if it exceeds 70% by mass, the drying energy cost in the next drying step increases or the particle size after drying varies. As a result, uniform firing may be difficult.

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

  Specific examples of hot air drying means that can be suitably used are such that the dehydrated product has a volume average particle diameter of about 250 to 3000 μm, preferably about 355 to 2000 μm, using a loosening facility such as an impeller. While loosening, hot air is blown by hot air blowing means provided below the impeller equipment, and hot air drying is performed. Of the deinked floss that has been loosened and dried, the deinked floss having a low specific gravity is discharged from the outlet provided in the upper part of the hot air drying means, whereby drying and classification can be performed. As a suitable means for classification of the dry deinking floss, a classification means using a cyclone can be adopted.

  In addition, it is preferable to adjust the particle size of the deinked floss (dried material) that has been dried and graded so that the particle size of 355 to 2000 μm is 70% by mass or more, and 72% by mass or more. It is more preferable to adjust, and it is especially preferable to adjust so that it may become 80 mass% or more. As described above, when the dried product is manufactured so that the particle size of 355 to 2000 μm is 70% by mass or more, that is, when the dried product of small-diameter particles is removed, partial over-burning is prevented, and firing is prevented. It becomes more uniform. Therefore, the possibility of practical use in terms of making the quality of the obtained regenerated particle aggregate uniform can be increased. Furthermore, when classification is performed after drying in this manner, dried particles having small diameters can be reliably removed, and the processing efficiency is also improved.

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

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

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

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

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

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

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

  Thus, since the firing temperature has a great influence on the whiteness and hardness of the regenerated particle aggregate to be produced, the firing conditions are 510 to 750 ° C. for primary firing and 500 to 700 ° C. for secondary firing. It is preferable that the primary baking is performed at 520 to 650 ° C, and the secondary baking is performed at 500 to 600 ° C. When the primary firing temperature is less than 510 ° C., the remaining amount of unburned matter is large, and the aggregate formation of the regenerated particles is insufficient. For example, the whiteness of the regenerated particle aggregate obtained is about 70% or more. May not reach. 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 difficult to use as a recycling resource, such as calcium oxide, calcium silicate, etc. May occur, and the resulting regenerated particle agglomerates may be melted by heat and may be extremely hard and reduce wire wear. On the other hand, when the secondary calcination temperature is less than 500 ° C., the organic matter may be insufficiently combusted or firing unevenness may occur, and the whiteness of the resulting regenerated particle aggregate may not be improved. Conversely, when the secondary firing temperature exceeds 700 ° C., the surface of the regenerated particle aggregate that has been baked and aggregated is exposed to a high temperature, which may cause melting to form an extremely hard melt. Because of the high temperature combustion, oxygen hardly reaches the regenerated particle core, and there is a possibility that firing unevenness or unfired parts are generated. Moreover, by making the secondary firing temperature lower by 10 to 50 ° C. than the primary firing temperature, it is possible to burn the unburned matter while preventing over-burning of the surface of the regenerated particle aggregate.

  Of course, the secondary firing temperature may be the same as the primary firing temperature. When the secondary firing temperature is set to the same temperature as the primary firing temperature, for example, 520 to 600 ° C., the firing proceeds slowly, the unburned material can be reduced, and the whiteness is preferably 70% or more. Can obtain a regenerated particle aggregate exceeding 80%. In this embodiment, the temperature difference between the primary firing temperature and the secondary firing temperature is based on the temperature at the upper end of the firing furnace.

  In the firing step, the oxygen concentration in the firing step is 0.05% or more, more preferably 0.1% or more, by at least one of means for blowing air into this step and means for exhausting air from within this step. It is preferable to adjust to 20% or less. In particular, the oxygen concentration in the firing step is 0.05 to 20% at the upper end in the primary firing furnace, more preferably 0.1 to 20%, more preferably 5 to 15%, and particularly preferably 7 to It is desirable to adjust to 13%, and it is desirable to adjust to 10 to 20% in the vicinity of the burner of the secondary firing furnace, more preferably to 12 to 18%. If the oxygen concentration at the upper end in the primary firing furnace is less than 0.05%, firing does not proceed and uneven firing proceeds, and there is a risk that enormous time and energy costs are required for firing. is there. On the other hand, if the oxygen concentration in the vicinity of the burner of the secondary firing furnace exceeds 20%, it is easy to overheat, and the regenerated particle aggregates turn yellow due to overheating unevenness, and the regenerated particle aggregates frequently melt and decompose. Oxidation and oxidation may make it difficult to use as a filler. In the present embodiment, the moisture content of the dried and classified deinked floss (dried material) supplied to the firing step is preferably about 2 to 20% by mass, more preferably about 5 to 15% by mass. Therefore, if the oxygen concentration in the firing process is 0.05 to 20%, the firing can proceed extremely efficiently, and the firing can be performed within 90 minutes, resulting in extremely high productivity. Can be obtained. For example, baking can be performed in about 60 minutes by making the moisture content of a dried material into 10 mass%.

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

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

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

  For example, particles obtained by firing are pulverized using a dry pulverizer such as a jet mill or a high-speed rotary mill, or a wet pulverizer such as an attritor, a sand grinder, or a ball mill, and the desired regenerated particle aggregate It can be. As the pigment, it is preferable that the particle diameter is uniform and fine, the ratio of particles having a particle diameter of 1 to 30 μm is 80% by mass or more, and the ratio of particles having a particle diameter of 40 μm or more. It is preferable that it is 0.4 mass% or less.

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

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

  Further, it is preferable to remove foreign matters other than the regenerated particle aggregates. For example, in the manufacturing process of waste paper pulp, sand, plastic foreign matters, metals, etc. are removed with a pulper, screen, cleaner, etc. before the deinking step Is preferable in terms of removal efficiency. In particular, iron content may reduce the whiteness of the regenerated particle aggregate by oxidation, and therefore it is preferable to avoid iron content and selectively remove it. The equipment in each process is designed or lined with materials other than iron to prevent iron from being mixed into the system due to abrasion, etc., and high magnetic materials such as magnets are selectively installed in the drying / classifying equipment. It is preferable to remove iron.

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

  Furthermore, in the present invention, a silica-coated regenerated particle aggregate in which the surface of the regenerated particle aggregate obtained through the above-described steps is coated with silica is particularly suitable as a regenerated particle aggregate that is a filler internally added to the pulp. Can be used.

  Silica is further precipitated on the surface of the regenerated particle aggregate to form a silica-coated regenerated particle agglomerate, so that it is reacted with sodium hydroxide in the used paper processing step in circulation use and used as a buffering agent or bleaching aid as a papermaking raw material. In addition, it can contribute to the recycling of inorganic particles. In addition, when such silica-coated regenerated particle aggregates are internally added to the pulp as a filler, it is possible to impart porosity that contributes to the improvement of the opacity and ink absorbability possessed by silica, and constitute book paper When the silica-coated regenerated particle aggregates are contained in the gaps between the pulp fibers, the displacement between the pulp fibers is suppressed, and for example, it is suppressed that the density is easily increased in the flattening process, and in the book processing of the resulting book paper The suppleness 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. Thus, when the regenerated particle aggregate having a high calcium ratio is internally added as a filler, the opacity of the resulting book paper may be slightly lowered, but the silica-coated regenerated particle aggregate having silica deposited on the surface, The function as a regenerated particle for papermaking is very high, and the opacity of book paper in which the silica-coated regenerated particle aggregate is internally added as a filler is sufficiently improved.

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

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

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

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

The type of the alkali silicate solution is not particularly limited, but a sodium silicate solution (No. 3 water glass) is particularly desirable from the viewpoint of easy availability. The concentration of the alkali silicate solution is such that the silica component in the regenerated particle aggregate is reduced and the silica content (SiO _{2) in the} solution is prevented so that silica does not easily precipitate on the surface of the regenerated particle aggregate. (Converted) is preferably 3% by mass or more, and the silica deposited on the surface of the regenerated particle aggregate becomes white carbon from the form of the silica sol, and the porosity of the regenerated particle aggregate is obstructed, opacity and printing In order to eliminate the possibility that the effect of improving the aptitude is insufficient, the silicic acid content is preferably 10% by mass or less.

  Thus, the regenerated particle aggregate used in the present invention contains three components of calcium, silicon and aluminum in the particle. In the elemental analysis using an X-ray microanalyzer (model number: E-MAX S-2150, manufactured by Hitachi, Ltd./Horiba, Ltd.), the particle constituents of the regenerated particle aggregate are converted to oxides, It is preferable that calcium, silicon, and aluminum are contained in a mass ratio of 20 to 82:10 to 40: 8 to 40, and the mass ratio is further 40 to 82:10 to 30: 8 to 30, In particular, it is preferably 60 to 82:10 to 20: 8 to 20.

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

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

  The regenerated particle aggregate used in the present invention contains silicon, and the silica particles made of silicon are fine, so the optical refractive index is high. Therefore, for example, a book paper in which a regenerated particle aggregate containing silicon in an oxide equivalent or more in the mass ratio is internally added as a filler has a particularly high opacity.

  In addition, for example, when a regenerated particle aggregate containing calcium in an oxide equivalent or more in the mass ratio is internally added as a filler, the whiteness of the book paper obtained can be improved.

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

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

  Further, in the regenerated particle aggregate, in order to adjust the total content ratio of calcium, silicon, and aluminum to 85% by mass or more in terms of oxides, for example, a means of using a flocculant that does not contain iron in the flocculation treatment of drainage sludge, Designing or lining the manufacturing equipment process with materials other than iron to prevent iron from entering the system due to wear, etc.Furthermore, high magnetic materials such as magnets are installed in the drying / classifying equipment to reduce the iron content. It is possible to adopt a means for removing. In particular, iron is preferably a causative substance that lowers the whiteness by oxidation, and thus is preferably removed selectively.

  By the way, calcium carbonate has homogeneous images such as hexagonal calcite crystals (calcite) and orthorhombic aragonite crystals (aragonite). Most limestones produced in nature are calcite crystals, and shellfish contain aragonite crystals in addition to calcite crystals. Furthermore, although not natural, calcium carbonate also has vaterite crystals. There are various kinds of calcium obtained from the deinking floss, but it becomes a substantially uniform calcium carbonate property by calcination and aggregation. Therefore, such calcium contributes to the quality stability of the regenerated particle aggregate itself, and the regenerated particle aggregate exhibits stable properties while being an aggregate composed of different components such as calcium, silicon, and aluminum.

  Further, the regenerated particle aggregate contains silicon, but since the primary particles of silica made of silicon are fine, the optical refractive index is high. Therefore, for example, when regenerated particle aggregates containing silicon in an oxide equivalent or more in the above-mentioned mass ratio are internally added as a filler, the opacity of the resulting book paper can be improved.

  Furthermore, since the regenerated particle aggregate used in the present invention has a flexible and porous property, it is particularly bulky and can contribute to flexible paper layer formation.

  The particle size of the regenerated particle aggregate used in the present invention is determined by a laser particle size distribution measuring device (laser diffraction type particle size distribution measuring device SALD) in terms of yield in the pulp and prevention of the regenerated particle aggregate from flowing into white water. -200, measured by standard refractive index (1), measured by Shimadzu Corporation), average particle diameter is preferably 0.05 μm or more, more preferably 0.3 μm or more, and printing From the viewpoint of maintaining suitability and preventing flatness from being lowered, the average particle size is preferably 16 μm or less, more preferably 10 μm or less.

  Further, the ratio of aggregates having a particle size volume distribution of 0.05 to 10 μm is adjusted to 80% by mass or more, and the ratio of aggregates having a particle size volume distribution of 20 μm or more to 0.5% by mass or less. More preferably.

  When the added amount of the regenerated particle aggregate as a filler is too small, the bulky effect of the regenerated particle aggregate may not be sufficiently exhibited. In contrast, the ash content is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, and particularly preferably 15 parts by mass or more. On the other hand, when the amount of the regenerated particle aggregate is too large, the paper strength of the resulting book paper may be reduced, so ash content is 35 mass with respect to 100 mass parts of pulp (absolutely dry pulp mass). Or less, more preferably 30 parts by mass or less, and particularly preferably 25 parts by mass or less.

  In the present invention, as the filler, in addition to the regenerated particle aggregates, clays such as calcium carbonate such as heavy calcium carbonate and light calcium carbonate, talc, kaolin clay, and delaminated clay are used. In addition, at least one selected from inorganic fillers such as titanium dioxide, synthetic silica and aluminum hydroxide, synthetic polymer fine particles such as polystyrene resin and urea formaldehyde resin, and the like, as long as the object of the present invention is not impaired. The blending amount can be appropriately adjusted and used.

  Furthermore, in this invention, you may mix | blend with pulp various additives normally mix | blended with paper to the stock slurry prepared from a pulp and the said filler. Examples of such additives include paper thickness improvers such as esters including polyhydric alcohol fatty acid esters and polycarboxylic esters, amines, amides, and higher alcohol alkylene oxide adducts; rosin, starch, CMC (carboxyl methylcellulose) , Polyvinyl alcohol, alkyl ketene dimer, ASA (alkenyl succinic anhydride), neutral rosin and other internally added sizing agents; starches, vegetable gums, aqueous cellulose derivatives, paper strength enhancers such as sodium silicate; polyacrylamide, Examples thereof include a yield improver such as a copolymer and sodium silicate, and these can be used by appropriately adjusting the type and blending amount thereof.

  In addition, when the paper thickness improver is blended, if the amount is too large, for example, as described later, when a surface treatment agent such as starch is applied after papermaking, uncoated defects of the surface treatment agent Therefore, it is preferable to adjust the amount to 0.5 parts by mass or less with respect to 100 parts by mass of pulp (absolutely dry pulp mass). In addition, when such a paper thickness improver is blended with a pulp containing a relatively small amount of mechanical pulp of 50% by mass or less and an amount of 0.5 parts by mass or less with respect to 100 parts by mass of pulp (absolutely dry pulp mass). In addition, a synergistic effect between bulkiness and flexibility is further exhibited.

  Paper stocks made from pulp slurry and fillers and, if necessary, paper stocks are, for example, long net paper machines, on-top paper machines, twin-wire paper machines, circular net paper machines, short nets, etc. Paper can be produced by a normal paper machine such as a paper machine. Further, in the present invention, a suitable Beck smoothness of, for example, 10 to 30 seconds can be imparted, for example, as described later without subjecting the obtained book paper to a surface treatment. The paper may be passed through and pressed and smoothed. As the calendering apparatus, it is possible to smooth the paper layer without strongly pressing by using a soft calender with a combination of a metal roll / resin roll rather than a machine calender with a combination of a normal metal roll / metal roll. It is more preferable because the paper layer strength can be sufficiently suppressed.

  The pH at the time of papermaking is, for example, as a filler, when calcium carbonate is contained in addition to the regenerated particle aggregate, the calcium carbonate dissolves and the yield decreases, or it causes soiling in the papermaking process. From the point of eliminating fear, it is preferable to adjust to about 5-8.

  Addition of the regenerated particle aggregate can be performed at any stage of the papermaking process, but it 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 hinder the binding between the pulp fibers, the stiffness of the book paper does not decrease too much. 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.

  Furthermore, in the present invention, after preparing a paper slurry from pulp and making paper, a surface treatment agent containing, as a component, a polymer material such as starch, polyvinyl alcohol, or polyacrylamide is applied to the surface. It is also possible to add colorants such as dyes and pigments to the slurry.

  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 amount of the surface treatment agent applied is preferably adjusted as appropriate in consideration of the surface strength of the target book paper.

The book paper thus obtained has the following formula (1):
B = (S × 10 ⁵ ) / T ³ (1)
(here,
B: supple index,
S: JIS P 8143 was measured according to the method described in "stiffness test method according paper Clark stiffness tester" described in the lateral direction Clark stiffness (cm ^3/100)
,
T: Paper thickness (μm)
Is)
The supple index represented by is 2.9 or less.

  Conventionally, it has been said that the stiffness is proportional to the cube of the paper thickness, and through the analysis and sensory test based on this finding, the results of an earnest study on the correlation between the stiffness and the paper thickness and the “flexibility” result. It has been found that the value obtained in (1) being 2.9 or less is an indicator of “flexibility” in the present invention. Thus, the flexible index B of the book paper of the present invention is 2.9 or less, preferably 2.5 or less, and more preferably 2.3 or less. In view of printing workability, ease of turning pages, and paper size, the supple index B is preferably 1.0 or more.

  Further, the Beck smoothness of the book paper of the present invention is measured in accordance with the method described in “Smoothness test method using paper and paperboard-Beck smoothness tester” described in JIS P 8119, and is 10 to 30 seconds. It is preferable that If the Beck smoothness is less than 10 seconds, the printability may be insufficient. Conversely, if it exceeds 30 seconds, the target bulkiness of the present invention may be impaired. The Beck smoothness is more preferably 12 seconds or more, and particularly preferably 15 seconds or more, from the viewpoint that sufficient satisfaction is imparted to the flatness of the book paper.

Further, the density of the book paper of the present invention is 0.63 g / cm ³ or less as measured according to the method described in “Paper and Paperboard—Test Method for Thickness and Density” described in JIS P 8118. It is preferable. If the density exceeds 0.63 g / cm ³ , it cannot be said to be bulky book paper, and the cushioning property is lowered. Therefore, when the Beck smoothness is 30 seconds or less as described above, the printability is poor. There is a risk that it will be sufficient. Incidentally, such a density, the bulkiness of the book paper, from the viewpoint of further sufficient satisfaction is given, more preferably 0.61 g / cm ³ or less, particularly preferably 0.60 g / cm ³ or less. In consideration of the interlaminar strength of the paper, ink penetration, and hand feeling, the density is preferably 0.30 g / cm ³ or more.

The basis weight of the book paper of the invention, from the viewpoint of securing paper quality strength, as measured in conformity with "grammage measuring method" described in JIS P 8124, 50g / m ² or more, further 55 g / m ² The basis weight is preferably 110 g / m ² or less, and more preferably 105 g / m ² or less from the viewpoint of weight reduction.

  The surface roughness (Ra) of the book paper of the present invention is described in JIS B 0651 “Geometrical Characteristic Specifications (GPS) —Surface Properties: Contour Curve Method—Probing Type” in terms of maintaining excellent flatness. It is preferably 2.7 μm or less, more preferably 2.5 μm or less, and particularly preferably 2.4 μm or less, as measured and calculated according to “Characteristics of surface roughness measuring machine”. In consideration of printing workability, offset printing suitability, and hand feeling, the surface roughness (Ra) is preferably 1.0 μm or more.

  Furthermore, the tensile strength of the book paper of the present invention is 2.0 kN, measured in accordance with “Paper and paperboard—Test method for tensile properties” described in JIS P 8113, from the viewpoint of ensuring good paper strength. / M or more, more preferably 2.1 kN / m or more.

  The book paper of the present invention was obtained by at least internally adding a specific regenerated particle aggregate produced at low cost by reusing deinking floss, which is a resource from the used paper processing process, as a filler. It has a specific supple index calculated from Clark stiffness and paper thickness. Therefore, the book paper of the present invention has both flexibility and flatness while maintaining bulkiness. The book paper having such excellent characteristics can be easily manufactured at low cost while being recycled by the manufacturing method of the present invention.

  Next, the book paper and its manufacturing method 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 Examples 1 to 20 and Comparative Production Examples 1 to 5 (production of regenerated particle aggregates or regenerated particles)
As shown in Tables 1 and 2, as raw materials, deinking floss (deinking floss discharged from the used paper processing process for producing used paper pulp) and / or paper sludge (mainly drained / dehydrated sludge discharged from the paper manufacturing process) ), The dehydration step, the drying step, and the firing step are sequentially performed under the conditions shown in Tables 1 and 2, and the particles are aggregated in the firing step (Production Examples 1 to 20). Regenerated particle aggregates (Production Examples 1 to 20) or regenerated particles (Comparative Production Examples 1 to 5) were obtained without performing the particle aggregation step after the wet pulverization treatment.

In Production Examples 3, 5, 19, and 20, the regenerated particle aggregate was added to and dispersed in a sodium silicate solution (water glass) to prepare a slurry, and then heated to the liquid temperature shown below while stirring. While maintaining, dilute sulfuric acid was added to form a silica sol. Next, the final reaction solution was adjusted to the pH shown below, and silica was deposited on the surface of the regenerated particle aggregate to obtain a silica-coated regenerated particle aggregate.
Production example: 3 5 19 20
Liquid temperature (° C.): 70 100 93 90
Final reaction solution (pH): 13.0 8.0 8.5 8.3

  Regarding the obtained regenerated particle aggregate (and silica-coated regenerated particle aggregate) or regenerated particles, the content of calcium, silicon and aluminum in the particle constituents (as oxide), the total content of calcium, silicon and aluminum (Converted to oxide), average particle diameter, ratio of aggregates or particles that are 0.05 to 10 μm in volume distribution of particle diameter, ratio of aggregates or particles that are 20 μm or more in volume distribution of particle diameter, appearance, wire The degree of wear, productivity and quality stability were investigated. These results are shown in Tables 3-5.

  Further, commercially available calcium carbonate (product number: TNC-N360, manufactured by Toyo Denka Kogyo Co., Ltd.) was used as Comparative Production Example 6, and the physical properties were measured in the same manner as the regenerated particle aggregate. These results are also shown in Tables 4 to 5.

  In addition, the various measured values shown to Tables 1-5 were measured with the following method.

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

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

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

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

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

(F) Average particle diameter and volume distribution of regenerated particle aggregates or regenerated particles 10 mg of a sample of regenerated particle aggregates or regenerated particles was dispersed for 3 minutes with an ultrasonic disperser (output: 80 W). Using this, an average particle size and a particle size were measured with a laser particle size distribution measuring device (laser diffraction particle size distribution measuring device SALD-2200, measured with standard refractive index (1), manufactured by Shimadzu Corporation). The ratio of aggregates or particles that were 0.05 to 10 μm and the ratio of aggregates or particles that were 20 μm or more were measured.

(G) Appearance (particle whiteness measurement and visual inspection)
(I) Measurement of particle whiteness Based on US TAPPI standard method T-646os75, it was measured with a whiteness meter (model number: KR-III type, manufactured by Kumagai Riki Kogyo Co., Ltd.).

(Ii) Visual observation The color of the regenerated particle aggregate or the regenerated particle was visually observed and classified into white and gray.

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

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

(G) Quality stability The degree of variation was measured for each item of whiteness, particle size, and production volume at a certain time interval, ranked in ascending order of variation, and evaluated based on the following evaluation criteria.
(Evaluation criteria)
◎: Up to the top 10 ○: 11-20th △: 21-23rd ×: 24th or lower

  From the results shown in Table 5, it can be seen that the regenerated particle aggregates of Production Examples 1 to 20 all have high whiteness, low wire wear, and excellent productivity and quality stability. . On the other hand, it can be seen that the regenerated particles of Comparative Production Examples 1 to 5 all have high wire wear and are inferior in productivity and quality stability.

Examples 1-20 and Comparative Examples 1-10 (Manufacture of book paper)
The pulps in the ratios shown in Tables 6 to 7 are beaten with a double disc refiner and mixed, and the types and addition amounts (ash content) shown in Tables 6 to 7 are added to 100 parts by mass of this pulp (absolutely dry pulp mass). A filler and an addition amount of a paper thickness improver shown in Tables 6 to 7 were added to obtain a pulp slurry.

Next, using this pulp slurry, paper was made at an on-top multi-cylinder type paper machine (Duoformer D type, manufactured by Ishikawajima Plant Construction Co., Ltd.) at a paper making speed of 800 m / min. Starch was applied to both sides so that the solid content was 0.5 g / m ² per side to obtain book paper.

The pulps and paper thickness improvers shown in Tables 6 to 7 are as follows.
Kraft pulp: LBKP beaten to 380 mL of CSF
Mechanical pulp: PGW beaten to CSF 120mL
Paper thickness improver: Part number PT8107 (manufactured by Seiko PMC)

  The Canadian Standard Freeness (CSF) is obtained by subjecting a sample to a disaggregation treatment with a standard disaggregator in accordance with “Pulp-Disaggregation Method” described in JIS P 8220, followed by “pulp drainage” described in JIS P 8121. This is a value obtained by measuring the freeness with a Canadian standard freeness tester in accordance with “degree test method”.

Various physical properties of the obtained book paper were examined according to the following methods. These results are shown in Tables 8-9. In addition, commercially available book papers 1 and 2 containing the same calcium carbonate as in Comparative Production Example 6 and containing the same paper thickness improver as described above were prepared, and the physical properties were examined in the same manner. The results are also shown in Table 9 as Comparative Examples 11-12. In these commercially available book papers 1 and 2, the addition amounts of calcium carbonate and paper thickness improver to 100 parts by mass of pulp (absolutely dry pulp mass) are as follows.
Calcium carbonate Paper thickness improver
(Ash content: parts by mass) (parts by mass)
Commercial book paper 1: 11.7 1
Commercially available book paper 2: 17.9 1

  Various values shown in Tables 8 to 9 were measured or calculated by the following methods.

(A) Clark stiffness in the horizontal direction Measured according to the method described in JIS P 8143.

(B) Paper thickness It measured based on the method of JISP8118.

(C) Supple index It calculated using the said Formula (1) from the measured value of Clark stiffness and paper thickness of a horizontal direction.

(D) Beck smoothness Measured according to the method described in JIS P 8119.

(E) Density Measured according to the method described in JIS P 8118.

(F) Basis weight It measured based on the method of JISP8124.

(G) Surface roughness (Ra)
The measurement was performed in accordance with the method described in JIS B 0651.

(H) Tensile strength Measured according to the method described in JIS P8113.

  Next, each characteristic was investigated about the book paper of Examples 1-20 and Comparative Examples 1-12 based on the following test examples 1-4. The results are shown in Tables 10-11.

Test example 1 (bulky)
Based on the measurement result of the density, evaluation was performed based on the following evaluation criteria.
(Evaluation criteria)
A: Density is 0.61 g / cm ³ or less.
○: density greater than 0.61 g / cm ^3, it is 0.63 g / cm ³ or less.
△: density greater than 0.63 g / cm ^3, it is 0.64 g / cm ³ or less.
X: The density is larger than 0.64 g / cm ³ .

Test Example 2 (Flexible)
Based on the calculation result of the supple index, evaluation was performed based on the following evaluation criteria.
(Evaluation criteria)
A: The supple index is 2.5 or less.
○: The supple index is larger than 2.5 and 2.9 or less.
(Triangle | delta): A flexible index is larger than 2.9 and is 3.2 or less.
X: The supple index is larger than 3.2.

Test Example 3 (Image feel (flatness))
Based on the measurement results of the Beck smoothness, evaluation was performed based on the following evaluation criteria.
(Evaluation criteria)
A: Beck smoothness is 15 seconds or more and 30 seconds or less.
A: Beck smoothness is 10 seconds or more and less than 15 seconds.
Δ: Beck smoothness is 8 seconds or more and less than 10 seconds.
X: Beck smoothness is less than 8 seconds.

Test example 4 (uncoated defect)
From 1,000 samples cut into sixty-six plates (1091 mm x 788 mm), 5 samples were randomly extracted, and iodine solution dissolved at a predetermined concentration was applied with a roller, and the presence or absence of an iodine-starch reaction was visually observed. I investigated. In the table, there is no uncoated defect when there is a reaction, and there is an uncoated defect when there is no reaction.

  The book papers of Examples 1 to 20 are regenerated particle aggregates containing three components of calcium, silicon and aluminum, which are obtained through a specific process using deinked floss discharged from the used paper processing process as a main raw material. It is obtained by internally adding to paper as a filler and making paper. Therefore, the book papers of Examples 1 to 20 not only can be obtained at low cost by reusing resources, but also have flexibility and flatness while maintaining bulkiness, and an appropriate basis weight, It can be seen that it has surface roughness and tensile strength and is free from uncoated defects.

  On the other hand, the book papers of Comparative Examples 1 to 5 were obtained by internally adding to the pulp regenerated particles not using the deinking floss discharged from the used paper processing step as a main raw material, and making paper. Therefore, it can be seen that the book sheets of Comparative Examples 1 to 5 cannot achieve resource saving and cost reduction, and are not compatible with bulkiness, flexibility, and flatness.

  Moreover, the book paper which added the general calcium carbonate as a filler of Comparative Examples 6-12, the book paper which does not add a filler internally, and also commercially available book paper are also bulky like Comparative Examples 1-5. It can be seen that pliability and flatness are not compatible.

  The book paper of the present invention can be suitably used, for example, as a text paper for various books. Further, according to the manufacturing method of the present invention, such book paper can be easily manufactured at low cost while reusing resources.

Claims (6)

Book paper in which a filler is internally added to pulp,
Deinking floss discharged from the waste paper treatment process is used as the main raw material, and the main raw material is obtained through a dehydration process, a drying process, a firing process and a pulverization process. In the firing process, the three components of calcium, silicon and aluminum are contained in the particles. Regenerated particle aggregates aggregated so as to contain at least internally added as the filler,
The following formula (1):
B = (S × 10 ⁵ ) / T ³ (1)
(here,
B: supple index,
S: JIS P 8143 horizontal Clark stiffness was measured according to (cm ^3/10
0),
T: Paper thickness (μm)
Is)
A book paper characterized by having a supple index represented by 2.9 or less.   In elemental analysis using an X-ray microanalyzer, the particle constituents of the regenerated particle aggregate contain calcium, silicon, and aluminum in a mass ratio of 20 to 82:10 to 40: 8 to 40 in terms of oxides. The book paper according to claim 1.   The book paper according to claim 1, wherein the regenerated particle aggregate is internally added in an amount of 5 to 35 parts by mass with respect to 100 parts by mass of pulp (mass of absolutely dry pulp). Book paper in which a filler is internally added to pulp,
Deinking floss discharged from the waste paper treatment process is used as the main raw material, and the main raw material is obtained through a dehydration process, a drying process, a firing process and a pulverization process. In the firing process, the three components of calcium, silicon and aluminum are contained in the particles. The silica-coated regenerated particle aggregate in which silica is further precipitated is added at least internally as the filler on the surface of the regenerated particle aggregate that has been aggregated to contain
The following formula (1):
B = (S × 10 ⁵ ) / T ³ (1)
(here,
B: supple index,
S: JIS P 8143 horizontal Clark stiffness was measured according to (cm ^3/10
0),
T: Paper thickness (μm)
Is)
A book paper characterized by having a supple index represented by 2.9 or less. A book paper manufacturing method for making paper by adding a filler to pulp,
Deinking floss discharged from the used paper processing process is the main raw material, and the main raw material is subjected to a dehydration process, a drying process, a baking process, and a pulverization process. In the baking process, the particles contain three components: calcium, silicon, and aluminum. Agglomerated to prepare regenerated particle aggregates,
As the filler, at least the regenerated particle aggregate is internally added to the pulp,
The following formula (1):
B = (S × 10 ⁵ ) / T ³ (1)
(here,
B: supple index,
S: JIS P 8143 horizontal Clark stiffness was measured according to (cm ^3/10
0),
T: Paper thickness (μm)
Is)
A method for producing book paper having a supple index represented by 2.9 or less. A book paper manufacturing method for making paper by adding a filler to pulp,
Deinking floss discharged from the used paper processing process is the main raw material, and the main raw material is subjected to a dehydration process, a drying process, a baking process, and a pulverization process. In the baking process, the particles contain three components: calcium, silicon, and aluminum. A regenerated particle aggregate is prepared by agglomeration as described above, and silica is further precipitated on the surface of the regenerated particle aggregate to prepare a silica-coated regenerated particle aggregate.
As the filler, at least the silica-coated regenerated particle aggregate is internally added to the pulp,
The following formula (1):
B = (S × 10 ⁵ ) / T ³ (1)
(here,
B: supple index,
S: JIS P 8143 horizontal Clark stiffness was measured according to (cm ^3/10
0),
T: Paper thickness (μm)
Is)
A method for producing book paper having a supple index represented by 2.9 or less.