JP4020932B2 - Printing paper - Google Patents

Description

  The present invention relates to printing paper such as paperback paper and comic paper.

  In general, printing paper refers to non-coated printing paper, fine-coated printing paper, and coated printing paper used for booklets such as books and reports, among the printing papers in the classification of production dynamic statistics surveys. Printing paper is used in particular for books, and is distributed based on a consignment system in which publishers line up at bookstores through agencies, and usually 30 to 40% that could not be sold at bookstores. The book is returned. The returned books will be sent to other bookstores as merchandise again. However, in the case of books using medium-quality paper, it is particularly discolored, so the top edge except the back (Top edge), the ground (Bottom edge) and fore edge (Front edge) are subjected to a polishing process called “retouching”.

  However, the polished surface after polishing is adjacent to each page of the book with wood pulp fiber, which is the raw material of printing paper, and clear coat agent (clear size agent) processed to prevent paper surface properties during printing. Blocking occurs at each of the top edge, bottom edge, and front edge, causing a problem that it is difficult to open the page. In order to eliminate such problems caused by blockages, it is necessary to page one page at a time, which causes the problem of troublesome work called “repair” and the lack of confirmation by such work. Since the product flows to the bookstore as it is, the quality of the book is greatly impaired.

  As a countermeasure, the present inventors conducted a study to change the pulp blending and the blending mass ratio of the internal filler, but did not lead to the solution of blocking between the pages, but conversely the tearing problem due to insufficient paper strength As a result, it was necessary to conduct further technological development.

  As a result of the measures for providing a small amount of coating layer on the paper surface as a further countermeasure against blocking between pages, the present inventors have obtained a result that the problem of blocking between pages can be almost solved. In printing and product processing stages, a small amount of coating layer causes a phenomenon that the paper does not slip during processing or transport, resulting in poor paper alignment in the cutting process, and problems with paper passing through the bookbinding machine. And further technical development. In the technical investigation by the present inventors, as a countermeasure against slip, an attempt was made to improve the Beck smoothness (JIS P 8119: 1998), which was conventionally about 50 seconds, to a highly smooth 78 seconds. The problem of still slipping did not improve.

  By the way, as a document related to printing paper used for books, there is, for example, Patent Document 1. Patent Document 1 proposes a method for producing a bulky paper using a bulking agent that is excellent in bulkiness effect and can suppress the decrease in paper strength, surface strength, and size. However, even when using bulky raw materials or using bulking agents to obtain density reduction, weight reduction, and flexibility, the paper surface tends to become rough. The printability such as fleshness is deteriorated. In addition, printing paper using a bulking agent has lower sizing and paper strength than ordinary high-quality paper, and if it is not produced by adding an excessive amount of sizing agent or paper strength enhancer, it can be used for book printing and bookbinding. It is said that it cannot withstand actual use including For this reason, it is necessary to limit the amount of bulking agent used or increase the amount of sizing agent and paper strength enhancer to produce, but in this way, the wire that squeezes water from wet paper in the papermaking process. Part and press part dirt, raw material pipes and the like are dirtied, and there is a problem that the production cost becomes high due to the necessity of cleaning and the like. In this respect, Patent Document 1 cannot find technical knowledge related to “blocking between pages” and “slip”, but naturally there is a tendency to separate the fibers due to their bulkiness. It is assumed that it is assumed that there are blocking and slippery problems between pages.

  In addition, as other documents related to printing paper used for books, there are, for example, Patent Document 2 and Patent Document 3. Among these, patent document 2 respond | corresponds to the improvement of an opacity by making a mechanical pulp and a filling amount high. On the other hand, Patent Document 3 applies the starch slurry to the surface of the base paper to prevent ink bleeding and improve the adhesion with the plate to cope with the improvement of printing suitability. However, when mechanical pulp is highly blended as in Patent Document 2, paper strength decreases. This reduction in paper strength is a more serious problem in recent years because printing speed has been increased. In addition, when the filling amount is high as in Patent Document 2, since interfiber bonding is inhibited, paper strength is reduced, paper dust is increased, and stiffness is reduced. Furthermore, even if the starch slurry is applied as in Patent Document 3, this alone does not sufficiently improve the printing suitability, and conversely, the impregnation of starch and the flattening treatment by a calendar, etc., reduce the bulkiness. To do.

  In the first place, these Patent Documents 1 to 3 do not disclose any means for solving the above-mentioned “blocking between pages” and “non-slip” problems.

  On the other hand, in the paper mills, with the increase in the use of waste paper (waste paper pulp), the generation of deinking floss discharged from the waste paper processing process and wastewater and dewatered sludge discharged from each paper manufacturing process has increased remarkably. Yes. This papermaking sludge contains a lot of inorganic materials such as fillers used for various papers and pigments used for paper coating layers. Conventionally, this papermaking sludge is burned to reduce its volume or to landfill. However, since the papermaking sludge contains a large amount of inorganic substances, a large amount of combustion ash (inorganic substances) remains even when burned, and the effect of volume reduction is low. Therefore, efforts have been made to utilize this combustion ash as a raw material for cement and soil improvement, but in these methods, combustion ash is only used as an auxiliary agent, and a large amount of incineration ash is used. In the end, most of the combustion ash will be landfilled.

  As a method of effectively using the combustion ash, it is conceivable to use it as an internal paper filler. However, since the whiteness of the combustion ash is low, it is suitable for use as an internal paper filler. Absent. Therefore, Patent Document 4 discloses a method of using combustion ash (incineration ash) after reburning and improving the whiteness.

  However, in the method of reburning the incinerated ash of Patent Document 4, it is necessary to set the reburning temperature to 500 to 900 ° C. in order to completely burn the unburned carbon, and the whiteness of the incinerated ash is 50 It has been found that it does not become suitable for use as a paper filler. Furthermore, it has been found that when the reburning temperature is set to over 900 ° C., the burning ash (inorganic matter) is sintered and melted and becomes extremely hard. In addition, when reburned ash is used as a filler, this reburned ash has very hard properties, so the papermaking wire wears out quickly, and the life of the papermaking wire becomes very short. It wasn't something that could be done. In this regard, it is conceivable to grind the reburned ash and reduce its particle size to reduce wear and improve smoothness, but when used as an internal filler, the yield during paper making is low. Since the combustion ash itself is extremely hard, the energy cost for pulverization is extremely high. In the first place, the biggest problem when paper sludge described in Patent Document 4 is used as a raw material is that the paper sludge used as a raw material flows out of the wire in the paper making process and is generated in the washing process in the pulping process. Collected from wastewater containing solids, those separated and recovered by solids separation equipment using sedimentation or flotation, etc. in wastewater treatment processes, those from which foreign substances have been removed in wastepaper treatment processes, etc. It is a point where various sludge is mixed. Among these papermaking sludges, for example, those that flow out through the wire in the papermaking process are mixed with a paper strength agent and the quality varies due to changes in the papermaking product in the papermaking process. Further, in the case of drainage sludge, a flocculant is mixed, and large fluctuations occur due to papermaking in the entire factory, fluctuations in production, or in-process cleaning of production facilities. In papermaking sludge generated from the washing process in the pulping step, various substances that cannot be made into fillers and pigments are mixed, such as fluctuations in chip moisture and pulp production conditions, resulting in quality fluctuations. Therefore, when trying to obtain papermaking fillers and pigments using various papermaking sludges without selection, the quality is greatly lowered, and the quality fluctuation is extremely large and unstable.

The conventional methods disclosed in Patent Document 4 and the like all start with simple recovery of paper-made recycled particles, are not suitable for use as recycled particles for printing paper, and lack quality stability. Met.
JP 2003-96692 A (paragraph numbers 0003 and 0004) JP-A-8-246390 JP 2001-316999 A JP-A-11-310732

  SUMMARY OF THE INVENTION The main problem to be solved by the present invention is to provide a printing paper having suitable workability that is more slippery and does not cause blocking between pages on a polished surface after polishing processing called “repair”. . Further, a subordinate problem to be solved by the present invention is to provide a printing paper that is bulky, has high opacity, and has good printability, while resources such as fillers and pigments are circulated and used at low cost. It is in.

The present invention that has solved this problem is as follows.
[Invention of Claim 1]
A printing paper having a coating layer mainly composed of a pigment and an adhesive on the surface of a base paper composed mainly of raw material pulp and filler ,
As the filler, in the used paper processing process for producing used paper pulp, the deinking floss separated from the pulp fiber in the deinking process for removing ink adhering to the used paper is the main raw material,
Including regenerated particle aggregates obtained through a dehydration step, a drying step, a firing step and a pulverization step,
As the pigment, in the used paper processing process for producing clay and used paper pulp, the deinking floss separated from the pulp fiber in the deinking process for removing ink adhering to the used paper is the main raw material,
Including regenerated particle aggregates obtained through a dehydration step, a drying step, a firing step and a pulverization step,
The ash content according to JIS P 8251 in the printing paper is 10 to 25%,
Printing paper, characterized in that an angle of starting to slide between coated surfaces based on a tilt method of JIS P 8147: 1994 is 22 to 32 °.

[Invention of Claim 2]
The printing according to claim 1, wherein the regenerated particle aggregate used as the filler and / or the pigment contains calcium, silicon, and aluminum in a mass ratio of 30 to 82: 9 to 35: 9 to 35 in terms of oxide. Paper.

[Invention of Claim 3]
The printing paper of Claim 1 or 2 containing the reproduction | regeneration particle | grains which the silica fixed to the surface of the said reproduction | regeneration particle as said filler and / or said pigment.

  According to the present invention, a printed paper having a suitable workability that is more slippery and does not cause blocking between pages on a polished surface after polishing called “repair”. In addition, according to the present invention, the resources such as fillers and pigments whose generation amount is remarkably increased due to the increase in the use of waste paper are recycled, and the cost is high. It becomes paper.

Next, an embodiment of the present invention will be described.
By repeatedly reviewing the color formulation, raw material blending, freeness (fiber length), ash content, blending amount of mechanical pulp in all pulp, mechanical pulp type, clear sizing agent coating amount, etc. The present invention has been found to solve the problems of blocking, slipping and glossiness between pages. In addition, as a result of earnest research focusing on recycling and use of raw material pulp and filler, which are the main constituent raw materials of paper from used paper, as a result of intensive research, component composition that forms recycled particles and these components are particles The present inventors have found a technique capable of obtaining a printing paper in which recycled particles that can be recycled as main constituent raw materials are used by limiting the ratio of the total to the whole.

  The printing paper of this embodiment has a coating layer mainly composed of a pigment and an adhesive on the surface of the base paper. The printing paper of this embodiment preferably contains, as the pigment, clay as a main component, and calcium carbonate and regenerated particles. And, when the pigment contains clay and calcium carbonate, it is possible to utilize the contradictory properties of slipperiness of clay and anti-slip property of calcium carbonate, without using other auxiliary agents, and containing clay and calcium carbonate. The slip angle can be adjusted by adjusting the amount. Here, “the main component” of clay refers to a case where the mass ratio of clay is 50% or more with respect to 100% of all pigments. When the mass ratio of the clay is 50% or more, the problem of slippage, which is a main problem to be solved by the present invention, is improved, and the problem of blocking between pages does not occur, so that smooth pages as printing paper can be obtained. It is characterized by a good feeling of touch and touch. By using regenerated particles, a low-density coating layer can be obtained and the bulkiness can be improved.

  The printing paper of this embodiment contains a predetermined ash content to prevent blocking between pages, and as an inorganic substance constituting this ash content, clay or Calcium carbonate is most suitable.

  The ash content in accordance with JIS P 8251 in this paper is 10 to 25%.

  If the ash content in the paper is less than 10%, blocking between pages may occur. On the other hand, if the ash content exceeds 25%, the paper strength of the printing paper is lowered, the rigidity of the printing paper is lowered and it is difficult to bend, and the handling of books and the like is deteriorated. As a secondary effect by adjusting the ash content to 10 to 25%, if the ash content is less than 10%, the entanglement of fibers constituting the printing paper is promoted, and the problem of blocking between pages is likely to occur. However, when the ash content exceeds 25%, the paper quality strength is inferior and the paper may be easily broken. Furthermore, when the ash content is adjusted to 10 to 25%, the texture and feel are good.

  If the slip angle is less than 22 °, the workability on the workbench is good, but there is a possibility that the processing suitability for books and the like and the shape stability of the books and the like are impaired. On the other hand, when the slip angle exceeds 32 °, the printing paper is difficult to slip and the workability is extremely poor.

  In order to make the sliding angle 22 ° or more, it is necessary to contain 50% or more of clay by mass with respect to all the pigments in the coating layer. If necessary, the slip angle can be adjusted by the following method. In order to adjust the slip angle higher, that is, to improve the slip resistance, it is desirable to use polyester acrylate as an auxiliary agent. On the other hand, in order to adjust the sliding angle to a lower level, synthetic particles such as polyethylene, polypropylene, polytetrafluoroethylene, carnauba and lanolin, or fine particles such as natural wax, polystyrene and polyacrylate are added to the coating composition. Thus, it is desirable to form a coating layer. The slip angle can be adjusted by appropriately blending a known pigment other than clay, for example, calcium carbonate.

  The printing paper of this embodiment has an average fiber length of 0.7 to 1.5 mm, preferably 0.9 to 1.3 mm when disaggregated based on JIS P 8220: 1998, and JIS P 8120 of the base paper: The quantitative analysis result of mechanical pulp based on 1998 is 30 to 80%, preferably 35 to 64%.

  When the average fiber length is 0.7 to 1.5 mm, the blocking problem between pages is further improved. In addition, when the average fiber length exceeds 1.5 mm, the pulp fiber end separated from the cross section of the printing paper at the time of polishing processing is easily entangled with other pulp fibers separated from the adjacent printing paper cross section by the polishing process, A blocking problem occurs between pages. On the other hand, if the average fiber length is less than 0.7 mm, the pulp fibers forming the paper layer of the printing paper become dense, resulting in a decrease in rigidity and opacity, and the entanglement between the pulp fibers because the constituent fiber length is short. Decreases and the paper strength decreases.

  The average fiber length can be adjusted, for example, by adjusting classification or beating.

  When the mechanical pulp quantitative analysis result is 30 to 80%, it becomes possible to obtain entanglement between pulp fibers due to high fibrillation despite the short fibers that are characteristic of mechanical pulp, and blocking problems between pages are prevented. However, the opacity, bulkiness and rigidity required for the printing paper are also improved. If the result of quantitative analysis of mechanical pulp is less than 30%, this effect is difficult to obtain. If it exceeds 80%, conversely, a problem of blocking between pages occurs due to entanglement of fibers between mechanical pulps.

  In the printing paper of this embodiment, the base paper is mainly composed of raw pulp and filler, and as the filler and / or pigment, preferably both, deinking floss is the main raw material, dehydration step, drying step, firing step And the calcium, silicon, and aluminum obtained through the pulverization step are in a mass ratio of 30 to 82: 9 to 35: 9 to 35, preferably 40 to 70:15 to 30:15 to 30, in terms of oxides. Preferably, the recycle particles contained in the range of 50 to 61:19 to 25:19 to 25 are contained, and the ash content in accordance with JIS P 8251 in the paper is 10 to 25%.

  The above regenerated particles are formed by agglomeration of fine inorganic particles to form a lump, which has a slight cushioning property due to the gaps between the fine inorganic particles and is porous, so that the bulk of the printing paper is high. Property, opacity and ink absorbency are improved. When the total content of calcium, silicon and aluminum is 90% or more, the density of the coating layer can be set low, and the flatness of the coating layer surface is improved. Furthermore, when the mass ratio of the regenerated particles to the raw material pulp is 1 to 30%, a bulky paper layer can be formed without reducing the paper quality strength, and a hand feeling can be produced, and opacity improvement and page turning can be achieved. The touch becomes better.

  The printing paper of this embodiment preferably contains regenerated particles in which silica is fixed on the surface of the regenerated particles as the filler and / or the pigment, preferably both. These silica fixing regenerated particles can further improve printing suitability due to the high opacity and ink absorption drying property of silica, and cause ink bleeding and printing crushing even when printing extremely fine print information. In addition, finer print information can be provided in a book.

Next, the regenerated particles including the silica fixing regenerated particles will be described in detail.
The regenerated particles of the present embodiment are 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, you may pass through the deinking floss aggregation process, the granulation process, the classification process provided between each process, etc. It is desirable to provide various sensors in the facility for producing regenerated particles to control the state of the object to be processed, the equipment, the processing speed, and the like.

  Recycled particles can be used as a filler for papermaking (for printing paper) as they are after passing through the pulverization process, but by further fixing silica to the regenerated particles, the function as regenerated particles can be achieved. It is possible to increase it further.

  Examples of fixing silica to regenerated particles are described below. As a suitable measure for fixing silica, the regenerated particles are added / dispersed in an alkali silicate aqueous solution, and after preparing the slurry, the liquid temperature is 70 to 100 ° C., more preferably, the acid is added in a sealed container. By doing so, silica can be fixed on the surface of the regenerated particles. Silica fixed on the surface of regenerated particles is obtained by reacting sodium silicate (water glass) as a raw material with a dilute solution of mineral acids such as sulfuric acid, hydrochloric acid, and nitric acid at high temperature, and by hydrolysis and polymerization of silicic acid. Silica sol particles having a particle diameter of 10 to 80 nm.

  The silica sol fine particles of about several nanometers produced by adding an acid such as dilute sulfuric acid to a sodium silicate solution are attached so as to cover the entire porous surface of the regenerated particles. The silica sol fine particles and silicon, calcium, and aluminum included in the regenerated particles are bonded to fix silica on the surface of the regenerated particles.

  The pH is in the neutral to weakly alkaline range, and the preferred pH is 8-11. If sulfuric acid is added until the pH reaches an acidic condition of less than 8, white carbon is generated instead of silica sol.

Although the alkali silicate aqueous solution used here is not particularly limited, a sodium silicate aqueous solution (No. 3 water glass) is desirable in view of availability. The concentration of the alkali silicate aqueous solution is preferably 3 to 10% by mass in terms of the silicic acid content (in terms of SiO ₂ ) in the aqueous solution. When the amount exceeds 10% by mass, the silica fixed to the regenerated particles becomes white carbon from the form of the silica sol, which impairs the porosity of the regenerated particles and lowers the effect of improving opacity and ink fixability. On the other hand, when the amount is less than 3% by mass, the silica component in the regenerated particles is reduced, and silica fixing to the surface of the regenerated particles is difficult to occur.

  Silica is fixed on the surface of the regenerated particles, and calcium, silicon, and aluminum are made into a mass ratio of 30 to 82: 9 to 35: 9 to 35 in terms of oxides, so that the ink fixing property and the opacity due to the silica fixing effect can be obtained. Can be improved.

  As an example of fixing silica to other regenerated particles, in the regenerated particle manufacturing process that goes through the dehydration process, drying process, firing process, and pulverization process, carbon dioxide is reacted with calcium oxide generated in the firing process to achieve calcium carbonate. In the means, sodium silicate (water glass) as a raw material is reacted with a dilute solution of mineral acid such as sulfuric acid, hydrochloric acid, nitric acid at high temperature, and a particle size of 25 to 75 nm obtained by hydrolysis reaction and polymerization of silicic acid. There is a means for fixing silica sol particles.

  In the production facility, in order to further stabilize the quality, it is preferable to classify the regenerated particles in order to make the particle size uniform in each process, and the quality can be improved by feeding back coarse particles and fine particles to the previous process. Stabilization can be achieved.

  In addition, it is preferable to granulate the dehydrated product that has been subjected to the dehydration treatment before the drying step, and it is more preferable to classify the granulated product to make the particle size uniform. The quality can be further stabilized by feeding back coarse or fine granulated particles to the previous process. In granulation, a known granulation facility can be used, and facilities such as a rotary type, a stirring type, and an extrusion type are suitable.

  In production facilities, it is preferable to remove foreign substances other than regenerated particles. For example, sand, plastic foreign substances, metals, etc. are removed with pulpers, screens, cleaners, etc. used in the preceding stage of the deinking process of the used paper pulp manufacturing process. It is preferable in terms of removal efficiency. In particular, iron contamination is a substance that causes the decrease in whiteness of fine particles due to oxidation, so it is recommended to avoid contamination and selectively remove it. Design or lining each process with materials other than iron. It is preferable to prevent iron from being mixed into the system due to abrasion or the like, and to selectively remove iron by installing a high magnetic material such as a magnet in a drying / classifying facility or the like.

  The regenerated particles of the present embodiment contain calcium, silicon, and aluminum at a mass ratio of 30 to 82: 9 to 35: 9 to 35 in terms of oxides, preferably 40 to 82: 9 to 30: 9 to 30 mass. The ratio is more preferably 60 to 82: 9 to 20: 9 to 20.

  As a method to adjust the oxide equivalent ratio of regenerated particles calcium, silicon and aluminum, the main method is to adjust the raw material composition in the deinking floss, but the source is clear in the drying / classification process and firing process It can also be adjusted by a method of adding a coating floss or adjustment process floss in the process by spraying or a method of containing incinerator scrubber lime.

  More specifically, for example, neutral papermaking wastewater sludge and coated paper manufacturing process wastewater sludge are used to adjust calcium in regenerated particles, and silicon is added in large amounts as an opacity improver. For the adjustment of aluminum, use the papermaking wastewater sludge used in the acid papermaking system and other sulfuric acid bands, and the wastewater sludge in the high quality papermaking process that uses a lot of clay. be able to.

  For example, the regenerated particles of this embodiment have an oil absorption of 30 to 100 ml / 100 g, and when used for internal addition in the paper making process, it is preferable to adjust the average particle size to 0.1 to 10 μm.

The regenerated particles of this embodiment are preferably treated so that the particles having a size of 40 μm or less are 90% or more before the pulverization step after the above-described dehydration step, drying step, firing step, and the like. This makes it possible to perform wet one-stage pulverization without performing multi-stage pulverization such as pulverization of large particles by dry pulverization and micronization by wet pulverization, which are generally performed conventionally. Thereby, the peak height of the average particle diameter in the differential curve of the particle size distribution by the Coulter counter method can be set to 30% or more. Furthermore, calcium, silicon and aluminum in the deinking floss can be converted to 30 to 30 in terms of oxides. By adjusting the mass ratio to 82: 9 to 35: 9 to 35, the pore volume of the regenerated particles is 0.15 to 0.60 cc / g, the pore surface area is 10 to 25 m ² / g, and the pore radius is It can be 300-1000 Angstroms.

In this embodiment, the above regenerated particles can be used alone, but such regenerated particles are usually used as a filler for internal addition, for example, heavy calcium carbonate, light calcium carbonate, talc, clay, kaolin. In addition, at least one filler (particles) selected from inorganic fillers such as titanium dioxide, synthetic silica and aluminum hydroxide, and synthetic polymer fine particles such as polystyrene resin and urea formaldehyde resin can be used in combination.

  When the ash content in accordance with JIS P 8251 in the paper containing recycled particles exceeds 25% by mass, the paper strength is reduced. Therefore, the ash content in the printing paper is 10 to 25% by mass, more preferably 14 to 21% by mass. Is preferred.

  Moreover, a well-known thing can be used as an additive added to paper stock slurry. For example, starch, vegetable gum, aqueous cellulose derivative, sodium silicate and the like are used as a paper strength enhancer, and rosin, starch, CMC (carboxyl methylcellulose), polyvinyl alcohol, alkyl ketene dimer, ASA (as a sizing agent) Alkenyl succinic anhydride), neutral rosin and the like, and as a yield improver, polyacrylamide and copolymers, sodium silicate and the like can be added by internal addition or size press. Furthermore, colorants such as dyes and pigments can be added as necessary.

  The kind of waste paper used as the raw material of the pulp which can be used suitably in this form is not specifically limited. For example, in addition to used newspapers, used in coated paper and non-coated paper in color or black and white printed flyers, magazine waste paper, bookbinding, printing plants, cutting plants, cutting paper, and offices. It is possible to use waste paper printed with an electrophotographic system, a thermal system, a thermal transfer system, a pressure-sensitive recording system, an inkjet recording system, and the like.

  In particular, in the case of printing paper containing 10 to 25% by mass, preferably 14 to 21% by mass of ash in accordance with JIS P 8251 in the paper, the waste paper pulp once becomes “paper” and is pulped again. Therefore, it is easy to make the paper flat and loose, but when combined with the regenerated particles used in this form, the bulk of the recycled paper pulp is due to the porous nature of the regenerated particles, the massive shape and the entanglement of the pulp fibers. It is possible to obtain a higher bulkiness in the maintenance of the cushioning property and the comparison with the same US basis weight. Furthermore, the regenerated particles on which silica has been fixed have a low density and a remarkable bulky effect. In particular, when the regenerated particles are silica-coated (fixed) regenerated particles, the ratio of calcium, silicon and aluminum is 30 to 62:29 to 55: 9 to 35 of calcium: silicon: aluminum in terms of oxide. Preferably there is. Thus, for example, when regenerated particles containing 30 mass% or more of calcium in terms of oxide are internally added to the raw material pulp as a filler, the whiteness of the obtained paper can be improved. Although it is common to use waste paper pulp for printing paper, it uses waste paper pulp as a raw material for environmentally friendly printing paper, and reuses waste that was originally disposed of in landfills as industrial waste. This makes it possible to produce printing paper that is more environmentally friendly.

  In addition to this, virgin pulp can also be used, and there is no restriction on hardwood materials and softwood materials, and pulps obtained from both raw materials can be arbitrarily blended. Also in the production method, kraft pulp (KP), sulfite pulp (SP), mechanically ground wood pulp (GP), refiner ground wood pulp (RGP), which are chemical pulping methods that are delignified by cooking liquor. ), Thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), chemiground pulp (CGP), semi-chemical pulp (SCP), etc. These pulps and regenerated particles are mixed so as to be a main constituent material, and a printing paper can be produced by using a known paper machine.

In this embodiment, the basis weight based on JIS P 8124: 1998 of the printing paper is not particularly limited, but if it is in the range of around 64 g / m ² , the desired effect using the regenerated particles according to this embodiment. Is preferable because it is remarkably exhibited. Of course, even a basis weight of 70 g / m ² about a cardboard or 45~55g / m ² about thin paper such as a card that exceeds this range, it is possible to apply the present embodiment.

  The addition of the regenerated particles can be performed at any conventionally known location, but is preferably performed between the raw material blending chest and the inlet. By adding in the meantime, the regenerated particles are easily dispersed and the fixability to the fibers is improved. As a result, the yield of filler (regenerated particles) is improved. Further, since the regenerated particles do not hinder the bonding between the fibers, the rigidity of the base paper is not lowered. In order to disperse the regenerated particles more uniformly and improve the fixing to the fibers, it is preferable to add them in the vicinity of the inlet as much as possible.

  In this embodiment, size press processing can be performed. As the size press method, a size press solution is applied to both sides of the base paper through a base paper between two press rolls, and three pairs of rolls (a fountain roll, a metering roll, The size press liquid is supplied between the fountain roll and the metering roll, transferred from the metalling roll to the applicator roll, and the size press liquid layer on the applicator roll and the base paper are transferred to the other side. For example, there is a method in which coating is performed by contacting with an applicator roll at a nip pressure. In addition, there are, for example, a tab size press, a calendar size press, and the like. In these methods, the starch concentration and viscosity to be used can be appropriately adjusted.

  Since the printing paper based on this embodiment uses regenerated particles with a high calcium content and high apparent whiteness, the whiteness based on JIS P 8148: 2001 is about 82% or more and about 84%, and JIS P 8149: 2000. Therefore, it is possible to obtain a quality that can be used as printing paper having an opacity of about 80 to 90%.

  Furthermore, even with an average roughness of 10 points, suitable printing is possible without causing the problem of transportability due to the excessively high flatness of 10.6 to 16.6 and without impairing the printing suitability because it is too rough. Paper can be obtained. The “ten-point average roughness” is a roughness at 25 mm obtained based on a roughness curve measured by a stylus type surface roughness measuring instrument based on JIS B 0601: 1982.

Here, a method for producing regenerated particles (hereinafter also referred to as “inorganic particles”) will be described in detail.
〔Overview〕
The production facility flow of the regenerated particles of this embodiment has a dehydration process, a drying process, a firing process, and a pulverization process, but further includes a deinking floss agglomeration process, a granulation process, a classification process provided between each process, and the like. May be.

  In FIG. 1, the example of a partial structure of the manufacturing equipment flow of the inorganic particle of this form was shown. This equipment is equipped with various sensors, and controls the state of processing objects, equipment, processing speed, and so on.

  Moreover, 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.

  In the present embodiment, the case where the deinking floss S is used as a raw material will be exemplified below, but other papermaking sludge such as papermaking sludge in the papermaking process can be appropriately used with the deinking floss as a main raw material.

〔material〕
In the used paper pulp manufacturing process, in order to continuously produce used paper pulp of stable quality, used paper is selected and selected, and used paper of a certain quality is used. For this reason, the types, ratios, and amounts of inorganic substances brought into the used paper pulp manufacturing process are basically constant. Moreover, even when waste paper contains plastics such as vinyl and film, which cause unburned materials to fluctuate in the method of producing inorganic particles, these foreign substances are before the deinking process to obtain deinking floss. Can be removed in stages. Therefore, deinking floss is a raw material for producing inorganic particles with extremely stable quality as compared with sludge generated in other processes such as a factory drainage process and a papermaking raw material adjustment process.

  The deinking floss referred to in the present specification refers to what is separated from the pulp fiber in the deinking process for removing ink adhering to the used paper in the used paper processing process for producing the used paper pulp.

[Dehydration process]
For further dehydration of the deinking floss S, known dehydration means can be used as appropriate. In one example of this embodiment, the deinking floss S is dehydrated by separating water from the deinking floss S by a rotary screen 14 serving as a dehydrating unit. In the rotary screen 14, the deinking floss S dehydrated to 95 to 98% of the moisture can be suitably sent to, for example, the screw press 15 and further dehydrated to 40% to 70%.

  As described above, if the deinking floss S is dehydrated in a multi-stage process and abrupt dehydration is avoided, the outflow of the inorganic substance can be suppressed and there is no possibility that the flocs of the deinking floss S will become too hard. In the dehydration treatment, an auxiliary agent for improving the dehydration efficiency such as a flocculant for aggregating the deinking froth S may be added, but it is preferable to use a coagulant that does not contain iron. When iron is contained, it causes a problem of lowering the whiteness of inorganic particles due to oxidation of iron.

  The deinking process of the deinking froth S is preferably adjacent to the inorganic particle manufacturing process in the present embodiment in terms of production efficiency, but is equipped with a facility adjacent to the used paper pulp manufacturing process in advance to transport the dehydrated product It is also possible to do.

[Drying process]
The dehydrated product D obtained by dehydrating the deinking floss S is transported to the constant supply unit 16 by transporting means such as a truck and a belt conveyor, and supplied from the constant supply unit 16 to the drying unit 17.

  The drying means 17 includes a drying container 17b to which a dehydrated product D is supplied, a pair of rolls 17a and 17a that scrapes the supplied dehydrated product D provided at the bottom of the drying container 17b, and the pair of rolls 17a and 17a. Hot air blowing means that blows hot air upward from the middle, mainly. Further, the hot air blowing means is configured such that a feeding flow path 56 is connected to the bottom of the drying container 17 b and hot air is blown into the drying container 17 b through the feeding flow path 56.

  That is, the main drying means 17 loosens the dehydrated product D weakly and finely by a tangible means such as a pair of rolls 17a and 17a, and loosely and loosely by an intangible means such as hot air. Thus, the moisture content of the dehydrated product D having various properties such as large, small, hard and soft can be controlled and the grain size can be stably controlled.

  In particular, when the dehydrated product D supplied into the drying container 17b is dehydrated to a moisture content of 40 to 70% by mass, the temperature of the hot air is preferably 100 to 200 ° C, and is preferably 120 to 180 ° C. Is more preferable, and 130 to 170 ° C. is particularly preferable. When the moisture content of the dehydrated product D is 40 to 70% by mass, it can be sufficiently dried even with hot air at 100 ° C. On the other hand, the temperature of the hot air is preferably 200 ° C. or lower. When the temperature of the hot air exceeds 200 ° C, the drying proceeds faster than the particle alignment of the dehydrated material D having various properties such as large, small, hard, and soft, so the difference in moisture content between the particle surface and the inside It is difficult to make the amount uniform.

  It is preferable to dry the above dehydrated product D so that the moisture content of the dried product K before the firing step is 2 to 20% by mass, and the moisture content of the dried product K is 3 to 15% by mass. It is more preferable to dry it so that the moisture content of the dried product K is 3 to 10% by mass. When the dehydrated product D is dried to a range where the moisture content is less than 2% by mass, a problem of over-burning occurs in the subsequent baking. On the other hand, when the dehydrated product D is dried in a range where the moisture content exceeds 20% by mass, it is difficult to reliably perform subsequent firing.

  The particle size of the dried product K is preferably adjusted so that the particle size of 355 to 2000 μm is 70% by mass or more, and adjusted so that the particle size of 355 to 2000 μm is 75% by mass or more. More preferably, it is particularly preferable to adjust the particle size of 355 to 2000 μm so that it is 80% by mass or more.

  When the dried product K is manufactured so that particles having a particle diameter of 355 μm to 2000 μm or more are 70% by mass or more, that is, when the dried product K of small particles is removed, partial over-burning is prevented, and the firing is uniform. Become. Therefore, it is useful for practical application in terms of uniforming the quality of the obtained inorganic particles. Furthermore, when the classification is after drying as in this embodiment, the dried product K of small-diameter particles can be reliably removed, and the processing efficiency is also improved.

[Baking process]
The dry matter K that has fallen to the bottom in the cyclone 18 is increased in vigor by the exhaust fan H provided in the transfer flow path 58 and in the middle of the transfer flow path 58, and constitutes a cyclone-type first firing stage. It is sent to the furnace 21.

  In the firing furnace 21, the dried product K is swirled and dropped to suppress particle refinement, and in this process, firing is performed to adjust the unburned content.

  Firing in the main firing furnace 21 is preferably performed such that the unburned rate is 5 to 30% by mass, more preferably 8 to 25% by mass, and 10 to 30% by mass. Particularly preferably. When the unburned ratio is less than 5% by mass, the particle surface is overfired in the firing, the surface becomes hard, the oxygen is deficient inside, and the whiteness of the inorganic particles is lowered. On the other hand, if the unburned rate exceeds 30% by mass, the surface of the particles is overfired in order to prevent the unburned matter from remaining after the subsequent burning and firing. Until it is burned and fired, the problem arises that the surface of the inorganic particles becomes hard.

  The form of the main firing furnace 21 is not particularly limited, but is preferably a cyclone type. According to the cyclone type, as described above, the unburned rate can be adjusted uniformly and reliably by suppressing the refinement of the particles.

  The firing temperature range is preferably in the range of 510 to 750 ° C. In the first stage firing, the temperature of the upper end of the firing furnace 21 is 510 to 750 ° C., and the temperature in the combustion firing furnace 25 is the upper end of the firing furnace 21. The temperature at the upper end of the firing furnace 21 is preferably 550 to 730 ° C., and the temperature inside the combustion firing furnace 25 is 510 to 680 ° C. lower than the temperature at the upper end of the firing furnace 21. More preferably, the temperature at the upper end of the firing furnace 21 is 580 to 700 ° C., and the temperature in the combustion firing furnace 25 is particularly preferably 550 to 660 ° C. lower than the temperature at the upper end of the firing furnace 21. When the temperature at the upper end of the firing furnace 21 is 600 to 680 ° C. and the temperature in the combustion firing furnace 25 is 580 to 650 ° C. lower than the temperature at the upper end of the firing furnace 21, the fine papermaking particles produced are recycled fillers and pigments. It will be suitable for use as.

  By making the temperature in the combustion firing furnace 25 lower by 10 to 50 ° C. than the temperature at the upper end of the firing furnace 21, the unburned material can be burned while preventing the surface of the fine particles for papermaking from being overfired.

  The fired product obtained in the firing furnace 21 is sent to the combustion firing furnace 25, which is the second firing stage, and is fired and fired. As the combustion firing furnace 25, a known apparatus such as a rotary kiln furnace, a fluidized bed furnace, a stalker furnace, a cyclone furnace, a semi-dry distillation / negative pressure combustion type furnace, etc. can be used. A rotary kiln furnace is preferred as a measure that can be uniformly burned while stirring without applying an excessive physical pressure.

[Crushing process]
In the method for producing fine particles based on this embodiment, if necessary, further known dispersion / grinding steps are provided, and finely granulated to a necessary particle size as appropriate, as a pigment for coating and a filler for internal addition. Can be used.

  In one example, after incineration, the fine particles obtained 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. For use in fillers and pigments, it is necessary to make the particle size uniform and fine, but it is optimal for fillers, pigments, etc. using fine particles obtained by the production method based on this embodiment. Regarding the particle diameter and pigment diameter, the fine particles of this embodiment have primary particles with an average particle diameter of 0.01 to 0.1 μm, and secondary particles in which the primary particles are aggregated have an average particle diameter of 0.1 to 10 μm. Preferably there is.

[Attached process]
In this production facility, in order to further stabilize the quality, it is preferable to classify the fine particle size uniformly in each process, and the quality can be improved by feeding back coarse particles and fine particles to the previous process. Can be stabilized.

  In addition, it is preferable to granulate the deinked floss that has been subjected to dehydration in the previous stage of the drying process, and it is more preferable to classify the granulated product to have a uniform particle size. It is possible to further stabilize the quality by feeding back the granulated particles to the previous process. In granulation, a known granulation facility can be used, and facilities such as a rotary type, a stirring type and an extrusion type are suitable.

  In this production facility, it is preferable to remove foreign matters other than fine particles. For example, sand, plastic foreign matters, metals, etc. are removed with a pulper, a screen, a cleaner, etc. before reaching the deinking step of the used paper pulp manufacturing process. Is preferable in terms of removal efficiency. In particular, iron contamination is a substance that reduces the whiteness of fine particles due to oxidation, so it is recommended to avoid iron contamination and selectively remove it. Design or lining each process with materials other than iron, It is preferable to prevent iron from being mixed into the system due to abrasion or the like, and to further remove iron selectively by installing a high magnetic material such as a magnet in the drying / classifying equipment.

  Furthermore, the inorganic particles produced by the method for producing inorganic particles according to the present embodiment are obtained by using calcium, silica, and aluminum in an oxide conversion of 30 to 82: 9 to 35: 9 to 35 in elemental analysis of fine particles using an X-ray microanalyzer. It is preferable to include by mass ratio. More preferably, it is a mass ratio of 40-82: 9-30: 9-30, More preferably, it is a mass ratio of 60-82: 9-20: 9-20.

  By including calcium, silica, and aluminum in a mass ratio of 30 to 82: 9 to 35: 9 to 35 in terms of oxides, the specific gravity is light and excessive aqueous solution absorption can be suppressed, so that the dehydrating ability in the dehydration process can be reduced. It is good, and not only the moisture adjustment in the drying process is easy, but also the ratio of unburned substances in the firing process and the possibility of causing excessive hardness due to sintering can be reduced.

  As a method for adjusting the mass ratio of the present embodiment in the firing process, the main point is to adjust the raw material composition in the deinking floss, but in the drying process and firing process, the coating floss and adjustment with a clear origin It is also possible to adjust by means for containing the process froth in the process by spraying or the like, or means for containing the incinerator scrubber lime.

  For example, using deinked floss as the main raw material, neutral papermaking wastewater sludge and wastewater sludge from the coated paper manufacturing process are used to adjust calcium in the inorganic particle aggregate, and opacity is used to adjust silica. Newspaper manufacturing wastewater sludge, which is added in large quantities as an improver, papermaking wastewater sludge that uses sulfuric acid bands such as acidic papermaking to adjust aluminum, and wastewater in the high quality papermaking process that often uses talc Sludge can be used.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to these Examples.

  Regenerated particles were produced under the conditions shown in Table 1, and printing paper was produced using the regenerated particles. Tables 1 to 3 show the properties of the recycled particles and the printing paper and the evaluation of the printing paper. Moreover, the commercially available printing paper was prepared as a test paper, and the property and evaluation were shown to Table 2 and Table 3 as Comparative Examples 5-7 similarly to the above printing paper. In Example 15 and Example 16, the regenerated particles having silica fixed in the present invention were used.

Measurement, analysis, and evaluation were as follows.
[Average particle size (at the drying process outlet)]
It measured by the X-ray microanalyzer.

[Mass ratio (at drying process outlet)]
A mass ratio of more than 2000 μm was measured with a 4.7 mesh sieve, a mass ratio of less than 355 μm was measured with a 42 mesh sieve, and a mass ratio at the entrance of the firing step was measured.

[Wire wear (recycled particle wear)]
The measurement was performed with a plastic wire abrasion meter (manufactured by Nippon Filcon for 3 hours) and a slurry concentration of 2% by mass.

〔productivity〕
Evaluating the raw material dewatering efficiency, productivity, and power required for grinding, in five stages, ◎ was the most efficient condition, ○ was good, and found problems in efficiency, productivity, or grinding △, the thing where actual operation is difficult was made x.

[Quality stability]
For each item of the regenerated particles obtained by a predetermined method, whiteness, particle size, production amount at a fixed time interval, measure the degree of variation, rank in order of small variation, ◎ up to the top 10 The 11th to 22nd positions were marked with ◯, the 23rd to 25th positions were marked with △, and the rest were marked with x.

〔Appearance〕
The regenerated particles were visually compared and judged to be white and gray.

[Oxide equivalent mass spectrometry]
Component analysis in terms of oxide was performed for each of CaO, SiO ₂ and Al ₂ O _{3 using an} X-ray microanalyzer (EMAX · S-2150 / manufactured by Hitachi Horiba).

[Average particle size]
10 mg of a sample was added to 8 ml of a methanol solution and dispersed with an ultrasonic disperser (output 80 W) for 3 minutes. This solution was measured with a Coulter counter particle size distribution analyzer (TA-II type manufactured by COULTER ELECTRONICS) using an aperture of 50 μm. However, for those that could not be measured with a 50 μm aperture, measurements were made using a 200 μm aperture. The electrolyte used was ISOTON II (trade name: manufactured by COULTER ELECTRONICS, 0.7% high-purity NaCl aqueous solution).

[Basis weight]
It was based on JIS P 8124: 1998.

〔density〕
It was based on JIS P 8118: 1998.

[Recycled filler (particle) blending ratio and ash content]
In accordance with JIS P 8251: 2003 (temperature: 525 ° C.), the ash content of the paper is adjusted, and the component analysis in terms of oxide is performed with an X-ray microanalyzer (EMAX / S-2150 / manufactured by Hitachi Horiba). It calculated from the ratio of the site | part detected by overlapping each element of Al.

[Hot water extraction pH]
It was based on JIS P 8133: 1998.

[Average fiber length]
It measured using the fiber lab measuring apparatus (made by Kayani).

[(Hunter) Whiteness]
It was based on JIS P 8148: 2001.

[(Hunter) Opacity]
It was based on JIS P 8149: 2000.

[Ten point average roughness (Rz)]
Using a stylus type three-dimensional surface roughness meter manufactured by Kosaka Laboratory, measurement was performed under the conditions of a reference length of 2.5 mm and an evaluation length of 12.5 mm. In addition, an evaluation result is the average value which measured 8 places.

〔curl〕
After copying A4 size paper in the CD direction and making a single-sided copy, place it on a flat table with the curl side facing up, and measure the value higher than the surface of the table in the four corners. The average value was evaluated. The printing paper is desirably 3 mm or less.

[Manufacturing stability]
In the production of printing paper using a paper machine, production is performed while appropriately adjusting and monitoring various operating conditions. The operational stability at that time was evaluated in five stages as shown below. If the evaluation is 2 or less, it is not at a commercially practical level, and it is difficult to continue production stably while maintaining the quality of the transfer paper above a certain level.
5: The state of the paper web on the paper machine is stable, and it can be stably produced without any problem under normal production conditions.
4: The web on the paper machine is generally stable and can be manufactured stably by adjusting the operating conditions.
3: The web on the paper machine is somewhat unstable, but can be manufactured by adjusting the operating conditions.
2: The state of the paper web on the paper machine is unstable, and paper breaks often occur even when the operating conditions are adjusted.
1: The strength of the web on the paper machine is low, it is difficult to respond by adjusting the operating conditions, and paper breaks frequently occur.
[Slide angle (slip angle)]
Based on the inclination method of JIS P 8147: 1994, the slip angle in the lateral direction (CD direction) when the front surface and the back surface were brought into contact with each other was measured.

[Static friction]
Based on JIS P 8147: 1994, the static friction in the lateral direction (CD direction) when the front surface and the back surface were brought into contact with each other was measured. As printing paper, 0.45-0.75 is desirable.

  The present invention can be applied as printing paper such as paperback paper and comic paper.

It is a manufacturing equipment flow chart of inorganic particles.

Explanation of symbols

  16 ... dehydration means, 17 ... drying means, 21 ... firing furnace, 23 ... heat exchanger, 25 ... combustion firing furnace, D ... dehydrated product, F ... pulverized product, J ... fired product, K ... dried product, S ... desorption Ink floss.

Claims (3)

A printing paper having a coating layer mainly composed of a pigment and an adhesive on the surface of a base paper mainly composed of raw material pulp and filler ,
As the filler, in the used paper processing process for producing used paper pulp, the deinking floss separated from the pulp fiber in the deinking process for removing ink adhering to the used paper is the main raw material,
Including regenerated particle aggregates obtained through a dehydration step, a drying step, a firing step and a pulverization step,
As the pigment, in the used paper processing process for producing clay and used paper pulp, the deinking floss separated from the pulp fiber in the deinking process for removing ink adhering to the used paper is the main raw material,
Including regenerated particle aggregates obtained through a dehydration step, a drying step, a firing step and a pulverization step,
The ash content according to JIS P 8251 in the printing paper is 10 to 25%,
A printing paper characterized in that the angle of the sliding start of the coated surfaces based on the inclination method of JIS P 8147: 1994 is 22 to 32 °. The printing according to claim 1, wherein the regenerated particle aggregate used as the filler and / or the pigment contains calcium, silicon, and aluminum in a mass ratio of 30 to 82: 9 to 35: 9 to 35 in terms of oxide. Paper. The printing paper of Claim 1 or 2 containing the reproduction | regeneration particle | grains which the silica fixed to the surface of the said reproduction | regeneration particle as said filler and / or said pigment.

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