JP5419619B2 - Heatset offset printing paper - Google Patents

Description

  The present invention relates to a printing paper containing a papermaking filler obtained from incinerated ash, and more particularly to a printing paper suitable for heatset offset printing.

  In recent years, reduction of industrial waste has been strongly demanded from the viewpoint of environmental conservation. The reduction of industrial waste is a request to all companies and local governments that are engaged in power generation and waste incineration, and the paper and pulp industry is no exception.

  Under such circumstances, handling of incinerated ash has become a major social problem. At present, some of the incineration ash is effectively used as recycled materials such as cement raw materials, iron-making antioxidants, admixtures, etc., but the rest are often landfilled as industrial waste. It is considered that the reason why reuse is not so advanced is that even if incinerated ash is discharged from the same equipment, the constituent elements are not constant, so the product quality of the reused product is not constant. Another possible cause is that the generation amount is enormous.

  However, on the other hand, the development of methods for reusing incineration ash is also progressing. The methods are broadly divided into (1) a method for reusing incineration ash as a raw material, and (2) some processing for incineration ash. There are two methods: a method of performing and reusing as a raw material after improving a specific property.

  As the former method, a method of reusing it as artificial soil by mixing cement raw materials, antioxidants for iron making, snow melting agents, organic sludge, etc. and incinerated ash has been studied and commercialized (Patent Literature) 1).

The latter method is more complicated because of the processing. As an example, Patent Document 2 discloses a porous material produced by carbonizing papermaking sludge and papers in a non-oxygen atmosphere at 650 ° C. or lower, and further hydrothermally synthesizing them in an alkaline aqueous solution. ing. Patent Document 3 discloses a regenerated particle aggregate obtained by using deinked floss as a main raw material, and subjecting the main raw material to dehydration, drying, combustion, and pulverization operations, including gehlenite (Ca ₂ Al ₂ SiO ₇ ) and A regenerated particle aggregate that suppresses the total content of hard substances such as anorthite (CaAl ₂ Si ₂ O ₈ ) to 2.0 mass% or less is shown. Furthermore, Patent Document 4 discloses a method for producing an inorganic material while applying heat treatment at 600 to 800 ° C. to an aqueous slurry discharge containing organic matter and inorganic particles, and suppressing decomposition of calcium carbonate in the discharge. Yes.

Both the former and the latter are common in that incinerated ash is not used as waste, but has some added value and is used again as a raw material, and is considered to reflect the current social background.
On the other hand, in order to reuse these products using incinerated ash, a lot of costs and energy may be required, or the quality of the reused product often does not reach the required quality. Also, from the viewpoint of life cycle assessment, the cost and energy required to recycle incineration ash and the quality of the obtained reused product are comprehensively judged and are not practically practical. There are also many. For example, as in Patent Document 2, enormous energy is required to perform carbonization treatment in a non-oxygen atmosphere and hydrothermal treatment in an alkaline aqueous solution, and the process becomes complicated. In Patent Document 3, since it is preferable to perform a plurality of stages of combustion using a plurality of combustion furnaces, it also consumes a large amount of energy and also requires a large amount of equipment space. It may be disadvantageous in terms of cost from the viewpoint of use. As described above, in order to perform various pretreatments for reusing incineration ash, a lot of costs and labor are required, which are often difficult in practice. This is also one of the reasons why recycling of incineration ash cannot be actively promoted.

On the other hand, in recent years, printing technology has made great progress such as colorization, high-speed mass printing, and automation.
Among various printing methods, the offset printing method has the advantages of good reproducibility of halftone dots, vivid color printing, high-speed and large-volume printing, and has become the mainstream of current commercial printing.

  There are two types of offset printing: a cold offset type that is dried without passing through a dryer after printing, and a heat set type that is dried through a dryer after printing. Newspaper papers are printed by cold offset printing using penetrating dry ink because there is a high need to deliver newer information to more readers faster. On the other hand, advertising flyers, magazines such as weekly magazines and manga, catalogs, pamphlets, etc. contain low-boiling petroleum solvents because they require a cleaner printing surface, although printing speed is slightly slower than cold offset printing. It is printed by heat set printing using ink. In either case, the paper is required to have good ink setting properties and ink setting properties. Also, high printing workability is required in order to realize high-speed and mass printing.

  In the first place, offset printing is a system in which dampening water and ink are supplied to a plate called a PS plate (Pre-Sensitized Plate), transferred onto paper via a blanket, and printed. The ink used is relatively high in tack. Has characteristics. For this reason, troubles are often caused by so-called piling, in which fibrous substances such as vessels are taken from the paper during printing and are deposited as paper dust on a plate or blanket. Therefore, it is necessary to stop the printing machine and clean the plate and blanket, which causes a significant decrease in printing workability.

  In addition, the demand for paper quality is increasing year by year, and there is a demand for paper that is lightweight but has excellent back-through (opacity during printing: a phenomenon in which characters and patterns on the opposite side can be seen through). Yes. There are several methods for improving paper breakthrough, but it is most effective to improve the opacity of the paper by using a filler having a high specific scattering coefficient. However, when the ash content in the paper (filler content in the paper) is increased, there arises a problem that the surface strength, tensile strength, and paper thickness of the paper are reduced. In particular, the decrease in surface strength increases the amount of paper dust accumulated on the blanket of the printing press and the wear of the printing plate, which causes blurring of characters and ruled lines, and ink inking properties such as solid surface roughness (imperfection of imperfections). Also has an adverse effect. These problems are fatal in heatset offset printing.

  In addition, waste paper is being used for environmental considerations, but most of the ash content in DIP is derived from the filler, so if the amount of paper brought into the paper increases, problems with paper dust may occur. Cause.

Japanese Patent Laid-Open No. 09-121684 JP 2004-277272 A JP 2008-190049 A JP-A-10-29818

  As described above, by adding a high amount of filler to the printing paper, it is possible to increase the opacity of the paper and suppress print back-through. However, when paper with a high amount of filler is subjected to offset printing, There has been a technical problem that it is likely to occur and ink inking property is reduced.

  An object of the present invention is to provide a heat-set type offset printing paper in which generation of paper dust and printing plate wear during printing are suppressed despite high ash content in the paper.

  The present inventor has added a paper-making filler made from incinerated ash after heat treatment at a temperature of 700 to 800 ° C. to the printing paper, so that the heat-set type can be used even when the ash content in the paper is high. It has been found that paper dust generation and printing plate wear during offset printing are suppressed, and ink deposition properties are improved, and the present invention has been completed. Further, the printing paper of the present invention has little wear on the printing plate during heat-set offset printing.

  As the incineration ash of the raw material in the present invention, one or more selected from the group consisting of paper sludge incineration ash, coal incineration ash, waste incineration ash including paper, biomass incineration ash, and combined fuel incineration ash are used, More preferably, paper sludge and / or coal incineration ash is used. Further, it is preferable that the paper filler used in the present invention has an average particle size of 0.1 to 10 [mu] m because it is effective in suppressing the generation of paper dust and the abrasion of the printing plate. Furthermore, the paper filler of the present invention preferably has a whiteness of 10% to 60%, more preferably 30% to 60%.

Although not limited to this, this invention includes the following invention.
(1) Contains a papermaking filler obtained by incinerating a raw material containing at least one selected from the group consisting of papermaking sludge, coal, paper-containing waste, biomass, and composite fuel at 700 to 800 ° C. Heatset offset printing paper.
(2) The heatset offset printing paper according to (1), wherein the papermaking filler has an average particle size of 0.1 to 10 μm.
(3) The heatset offset printing paper according to (1) or (2), wherein the whiteness of the papermaking filler is 10 to 60%.
(4) The heatset offset printing paper according to any one of (1) to (3), wherein the ash content in the paper is 10% by weight or more.

  In the present invention, since incinerated ash discharged from combustion equipment such as a boiler is used as a filler for papermaking, it is preferable from an environmental viewpoint such as waste reduction. In the present invention, by using the above papermaking filler, even when the ash content in the paper is high, it is excellent in printing quality such as ink inking property, and generation of paper dust and printing plate wear during printing is suppressed. Heat set offset printing can be obtained. In addition, the printing paper of the present invention internally incorporated with a papermaking filler obtained by incinerating a specific raw material at a predetermined temperature of 700 to 800 ° C. has a characteristic that the offset printing plate is not easily worn during offset printing. And is particularly suitable as an offset printing paper. Furthermore, since the paper filler used in the present invention can be produced by a relatively simple method using incinerated ash as a raw material, it is extremely advantageous and practical from the viewpoint of waste reduction, energy, and cost.

FIG. 1 shows the result of X-ray diffraction analysis of the crystal composition of the papermaking filler used in the present invention.

Hereinafter, the details of the papermaking filler using the incinerated ash contained in the heatset type offset printing paper of the present invention and the method for producing the same will be described.
Papermaking Filler The papermaking filler of the present invention is incinerated ash obtained by heat-treating a raw material at a temperature of 700 to 800 ° C. In general, incineration ash is mainly composed of various metals and inorganic substances such as oxides, sulfides, and chlorides thereof, but the composition thereof is very complicated and varies depending on the incinerated products and the production area. Incinerated ash may contain halogens and heavy metals in addition to inorganic oxides such as SiO ₂ , Al ₂ O ₃ , CaO, and MgO, organic substances in combustion raw materials such as unburned carbon. As described above, the composition of incineration ash varies depending on the location and season, but in order to reuse industrially stably, such incineration ash with a non-constant composition is used as a raw material for a certain level of papermaking. It is required that the filler can be manufactured stably. Under such circumstances, the inventor has surprisingly found that the wire wear degree of the incineration ash is improved by controlling the incineration temperature when obtaining the incineration ash to 700 to 800 ° C. . That is, according to the present invention, it is possible to stably produce a paper filler with excellent wire wear properties from various raw materials regardless of combustion conditions such as the time for heat treatment and the shape of combustion equipment. . As demonstrated in the examples described later, by burning the raw material in the presence of oxygen at a heat treatment temperature of 800 ° C. or lower, the wire wear resistance is remarkably reduced and it can be suitably used as a filler for papermaking. become. On the other hand, when the heat treatment temperature is lower than 700 ° C., the combustion efficiency is lowered, and many unburned components mainly composed of unburned carbon remain, which is not preferable. From the viewpoint of combustion efficiency and the like, in a more preferred embodiment, the combustion temperature of the present invention is 750 to 800 ° C.

In general, the temperature at which the incineration raw material is heat-treated is set according to the specifications of the incineration equipment so that the raw material is sufficiently incinerated and has desired effects in energy recovery, volume reduction, and the like. In recent years, in order to suppress the generation of dioxins during incineration, it is common to incinerate raw materials at temperatures exceeding 800 ° C. However, when incineration is carried out at a temperature exceeding 800 ° C., aluminum calcium silicate typified by gehlenite (Ca ₂ Al (AlSi) O ₇ ) is produced. When the incinerated ash containing gehlenite or the like is used as a filler for papermaking, the papermaking wire of the papermaking machine is significantly damaged. Although the details of the mechanism by which the filler for papermaking excellent in wire wear resistance is obtained by the present invention are not clear, the amount of gehlenite contained in the incineration ash is reduced by lowering the incineration temperature of the raw material to 700 to 800 ° C. It is presumed to have something to do with it. In addition, the gehlenite etc. which are contained in incineration ash can be confirmed by X-ray diffraction.

  In addition, the offset printing paper containing the papermaking filler of the present invention hardly generates paper dust during heat-set offset printing even when the ash content in the paper is increased, and the offset printing plate is not easily worn. When the papermaking filler of the present invention is used, the details of the reason why paper dust is less likely to be generated and the printing plate for offset printing is difficult to wear is not clear, and the present invention is not limited to the following. By lowering the incineration temperature to 700 to 800 ° C., it is presumed that the generation of a substance having high hardness is suppressed, thereby reducing the number of particles that easily fall off from the paper layer structure.

  In the present invention, the wire wearability can be remarkably improved by heat-treating various incineration raw materials at a temperature of 700 to 800 ° C., but various incineration raw materials can be reused as a filler for papermaking, so the application range thereof Is wide. The incineration raw material used as a raw material can be used singly from a single source, or can be used by mixing from a plurality of sources. When mixing a plurality of incineration ash burned at a temperature of 700 to 800 ° C to make a filler for papermaking, each incineration ash needs to be heat-treated at a temperature of 700 to 800 ° C. The generated combustion equipment method and ash raw material may be different.

  In the present invention, the combustion apparatus is not particularly limited. For example, a stoker furnace (fixed bed), a burner furnace, a fluidized bed furnace, a fuel injection furnace, a cyclone furnace, a kiln furnace, an internal heat combustion furnace such as a multistage combustion furnace, A combustion apparatus such as an indirect heating type external heat combustion furnace using heavy oil or the like as a heat source can be used, and a stalker furnace (fixed bed), a burner furnace, a fluidized bed furnace, or a kiln furnace is preferable. Moreover, although combustion time (residence time) can also be determined according to the quantity of raw materials, oxygen conditions, etc., 0.1 to 60 seconds are preferable and 0.2 to 30 seconds are more preferable. Although the oxygen concentration in a combustion apparatus can also be suitably determined according to conditions, from a viewpoint of combustion efficiency, 0.1 to 15% is preferable and 1 to 10% is more preferable.

  Examples of the raw material of the present invention include papermaking sludge, coal, paper-containing waste, biomass, composite fuel, and the like, and other materials may be included in addition to these. Among them, it is preferable in the present invention to use paper sludge and / or coal incineration ash.

  Incineration residue obtained by heat-treating sludge (PS: paper sludge, also called paper sludge) generated in the paper making process at 700 to 800 ° C. in various combustion facilities such as a kiln and a heat recovery boiler (Incineration ash) can be suitably used. The incineration ash obtained from sludge derived from the papermaking process consists of inorganic pigments such as calcium carbonate, titanium dioxide, talc and kaolin discharged from the waste paper recycling process and papermaking white water, aluminum sulfate as an inorganic flocculant, and ink components and fibers. It includes a part of. In the present invention, when a paper filler is manufactured using sludge from the paper manufacturing process as a raw material, it can be reused as a paper manufacturing raw material while reducing waste from a paper mill, and it is extremely advantageous because it does not involve transportation costs. It is. Also, the incineration ash of paper sludge is advantageous in that its composition is relatively stable. The papermaking sludge combustion facility is not particularly limited, and examples thereof include a rotary kiln and a sludge boiler.

  Examples of the papermaking sludge of the present invention include sludge from a used paper recycling process (DIP process), a pulp manufacturing process, a papermaking process, and the like. Papermaking sludge is mainly composed of solids in wastewater washed away from the wastepaper recycling process, pulp manufacturing process, papermaking process, etc. And sludge obtained by dehydrating the waste liquid after the treatment. Such papermaking sludge contains fibers, ink particles and the like in addition to inorganic fillers and inorganic pigments such as kaolin clay and calcium carbonate.

  In the present invention, coal incineration ash refers to coal burnout generated in combustion equipment. In general, it is said that coal ash has a particle size of almost 100 μm or less in fly ash and a size of 1 to 1 mm or more in bottom ash. In the present invention, coal ash having any size and shape is used for papermaking. It may be used as a filler. As the coal incineration ash, for example, the coal incineration ash discharged from pulverized coal boilers in the electric power industry and the like, and the coal incineration ash obtained from the coal combustion facility of the paper mill can be used as a raw material for the paper filler of the present invention. .

  In the present invention, paper-containing waste includes various types of waste other than paper, in addition to waste mainly composed of so-called waste paper and waste paper, which is no longer necessary in homes, offices, and papermaking processes. This includes waste that is generated. For example, even if paper coated with a resin film or the like is used as a raw material, according to the present invention, a papermaking filler having excellent wire wear can be obtained.

  In the present invention, the biomass is an organism-derived industrial resource. For example, waste biomass includes paper, livestock manure, food waste, construction waste such as wood chips and wood flour, black liquor, sewage sludge, and raw garbage. Examples of unused biomass include agricultural waste such as rice straw, wheat straw, and rice husk, forest land residues such as thinned and damaged wood, timber, resource crops, and feed crops.

  In the present invention, the composite fuel is a material obtained by converting a material such as waste, such as waste solid fuel (RDF), and is mainly used for obtaining thermal energy by combustion, and is disposed of. It is effectively used as fuel for power generation and boilers. For example, RDF is a solid fuel made of waste such as raw garbage and plastic garbage that is thrown away at home and can be suitably used in the present invention. In addition, RPF (Refuse Paper & Plastic Fuel) obtained from waste, mainly waste paper and waste plastics, has a clear content of waste, so its calorific value is easy to control and its water content is low. Since polyvinyl chloride (PVC), which is considered to be the cause of the occurrence of the above, can be excluded, it can be particularly preferably used in the present invention.

  The papermaking filler of the present invention can of course be used as a papermaking filler without any treatment on the incinerated ash heat-treated at 700 to 800 ° C., but the incinerated ash is subjected to a pulverization treatment to obtain an average particle size. It is preferable to use as 0.1-10 micrometers. In general, calcium carbonate, filler kaolin, talc, hydrous silicic acid (white carbon), titanium dioxide, etc., used as a papermaking filler, when used as a papermaking filler, preferably have an average particle size of 0.1 to 30 μm. Has been. However, since incineration ash has a relatively high hardness, if paper is manufactured by simply adding incineration ash in the above-mentioned particle size range, the wire life of the paper machine will be greatly worn, shortening the wire life. There was a problem that productivity was remarkably lowered. In the present invention, by pulverizing the incinerated ash to make the particle size in the range of 0.1 to 10 μm, the wire wearability is greatly improved. Details of this reason are not clear, and the present invention is not limited to the following, but the incineration ash having high hardness is appropriately pulverized by the pulverization treatment, and the weight of the filler particles is reduced, so that the particles are put in the paper machine. Since the kinetic energy at the time of moving is reduced, it is presumed that the wire wearability is improved.

  In consideration of the balance between filler yield and wire wear, the papermaking filler of the present invention preferably has an average particle size after pulverization of incinerated ash of 0.1 to 10 μm, preferably 0.5 to 5.0 μm. More preferably, 1.0-4.0 micrometers is further more preferable, and 1.0-3.0 micrometers is the most preferable. If the average particle size is smaller than 0.1 μm, it is difficult to stay in the paper in the paper making process and the yield of incinerated ash in the paper is lowered, which is not industrially preferable.

  The incineration ash in the present invention can be pulverized by various methods, and is preferably pulverized using a pulverizer. The pulverization method can be either dry or wet. Pulverizers used in the pulverization process include ball mills, rod mills, and other broad ball mills; bead mills, tower mills, attritors, sateley mills, sand grinders, annular mills, and other medium agitation mills, colloid mills, homomixers, homogenizers, and inline In addition to a high-speed rotary pulverizer such as a mill, a dry pulverizer such as a jet mill, a dry bead mill, or a dry ball mill may be used. In addition, a classification step using a sieve or the like can be combined for the purpose of increasing the efficiency of pulverization or removing non-standard products before, after or during the pulverization step. Examples of classification means using a sieve include a vibrating sieve, an ultrasonic sieve, a jet screen, an air separator, and a trommel screen. The pulverization step may be performed by combining a plurality of pulverizers. The pulverizer used at this time may be dry or wet as described above, and a dry pulverizer and a wet pulverizer may be used in combination.

  In the case where the incineration ash is pulverized in a wet manner in the present invention, the incineration ash is slurried prior to the wet pulverization. Although there will be no restriction | limiting in particular if the density | concentration of a slurry is a density | concentration which can perform wet grinding, 0.05 to 50% is preferable and 1 to 40% is more preferable. If it is less than 0.05%, the amount of particles produced is small and the efficiency is poor, and if it exceeds 50%, the fluidity of the slurry is deteriorated and the operability of the pulverization process may be lowered. Before applying the slurry to the pulverizer, it is desirable to uniformly disperse the incinerated ash particles in the slurry by stirring and dispersing treatment. This agitation / dispersion treatment poses no problem unless the incinerated ash is sufficiently dispersed and extremely agglomerated, and there is no particular limitation on time, agitation strength, and the like. As the stirrer or disperser, known stirrers or dispersers including, for example, an agitator, a homomixer, a homogenizer, a mixer and the like can be used without any problem. The solvent of the incineration ash slurry is preferably an aqueous solvent.

  In carrying out the pulverization step and / or slurry dispersion treatment in the present invention, a pulverization aid and / or a dispersant may be used for the purpose of adjusting the viscosity. The type of grinding aid used for dry grinding is not particularly limited, and known grinding aids such as alcohols such as ethanol and isopropyl alcohol, propylene glycol, triethanolamine, triethylamine, water or water-based aids. It can be used without any problems. Further, the type of the dispersant used for the wet pulverization and / or slurry dispersion treatment is not particularly limited, and an aqueous polymer containing acrylic acid, methacrylic acid, polyacrylic acid, and derivatives and salts thereof as constituents Any known dispersant can be used without any problem. The addition amount of the grinding aid / dispersant is appropriately adjusted according to the particle size, particle size distribution, slurry concentration, viscosity and the like.

  The pH of the papermaking filler of the present invention is preferably adjusted to a range of 7 to 10, and more preferably adjusted to a pH of 8 to 10. Incinerated ash generally shows a high alkalinity of pH 11 or higher, and if this alkali content is brought into the paper machine as it is, there is a possibility that the effects of various chemicals added to the paper stock may be hindered. When the incinerated ash of the invention exhibits high alkalinity, it is desirable to perform pH adjustment treatment on this. If the pH is more than 10, when added internally as a papermaking filler, the effects of various chemicals added to the paper may be hindered. In addition, a large amount of an acidic substance is required to make the pH less than 7, which is not industrially practical. In addition, when sulfuric acid or sulfate is used as an acidic substance, it reacts with calcium contained in ash. As a result, calcium sulfate is produced, which may increase the possibility of scale generation in the paper machine. In the present invention, the pH of the papermaking filler refers to the pH of the slurry when the papermaking filler is dispersed in water to prepare a slurry having a solid content of about 12% by weight.

  A method for adjusting the pH of the papermaking filler of the present invention is not particularly limited, but a method of adding an acidic substance to incinerated ash is simple and preferable. Acidic substances to be added include inorganic acids such as hydrochloric acid, sulfuric acid, nitric acid and carbonic acid, organic acids such as citric acid, gaseous acids such as carbon dioxide, and acidic metals such as aluminum sulfate (sulfuric acid band) and magnesium sulfate. Acids including salts can be used alone or in combination. It is industrially preferable to use sulfuric acid or aluminum sulfate from the viewpoint of easy availability in paper mills, cost and workability.

  When adjusting the pH in the present invention, the step of adjusting the pH may be performed at any stage before the pulverization process, during the pulverization process, or after the pulverization process, or may be performed in a plurality of stages. On the other hand, in order to uniformly adjust the pH of the incinerated ash, it is preferable to disperse the incinerated ash into a slurry and then add an acidic substance to the slurry. When the acidic substance is added, it is desirable to uniformly disperse the acidic substance in the slurry by stirring and dispersing treatment. This agitation / dispersion treatment is not a problem as long as the acidic substance is sufficiently dispersed, and there is no particular limitation on time and agitation strength. As the stirrer or disperser, any known stirrer or disperser including, for example, an agitator, a homomixer, a homogenizer, and a mixer can be used without any problem. In addition, when an acidic substance is added at the same time as the pulverization process, it is considered that the acidic substance is dispersed in the slurry by the pulverization process, so the pH should be sufficiently adjusted even if the step of performing only the stirring process is omitted. Can do.

  The incinerated ash material of the present invention can be filtered, washed with water, and redispersed for the purpose of removing by-products. In addition, when drying is necessary for transportation or the like, it can be dried by heating or reduced pressure. The paper filler of the present invention can be subjected to a drying treatment because the physical properties hardly change even if it is dispersed again after drying to form a slurry.

  The incineration ash material obtained by the present invention has the same whiteness as that of the incineration ash when the incineration ash is used as it is as a filler for papermaking. Also, when the incinerated ash is used after being pulverized, the whiteness of the papermaking filler is almost the same as that of the incinerated ash used as a starting material, and the average particle size is preferably 0.1 to 10 μm. By adjusting the temperature at which the incinerated ash used as a raw material is subjected to heat treatment to 700 to 800 ° C., it is possible to remarkably improve the wear properties that have been an inevitable problem in the conventional use of incinerated ash. The whiteness of the paper filler of the present invention is low compared to calcium carbonate, filler kaolin, talc, hydrous silicic acid (white carbon), titanium dioxide, etc., which are generally used as paper fillers, but low because of excellent wire wear. Whiteness grade paper can be used without any problem, and even high whiteness grade paper can be used by adjusting the addition rate or combining with other papermaking fillers. In general, it is difficult to increase the whiteness of the incinerated ash, and enormous costs and work time are essential.However, in the present invention, since the process of adjusting the whiteness is not essential, it is extremely economical to adjust the starting material. The incinerated ash material in which the whiteness is substantially maintained can be used as a filler for papermaking. Since the whiteness of the incinerated ash is generally 60% or less, the whiteness of the papermaking filler of the present invention is 60% or less unless the whiteness improvement treatment is performed. On the other hand, the whiteness of the papermaking filler of the present invention is preferably 10% or more, and more preferably 30% or more in order to maintain a practical level as a papermaking filler. If the whiteness is 30 to 60%, a desired quality can be achieved at the same time while effectively using waste without significantly reducing the whiteness of the paper. If the whiteness of the papermaking filler is less than 30%, there is a possibility that the whiteness of the paper cannot be fully maintained when internally added to the paper, but the effect of increasing the opacity of the paper is Depending on the required quality, it may be used appropriately. Moreover, the use of coal ash having a relatively low whiteness can be expected to lead to further reduction of waste. Of course, in order to increase the added value as a paper filler, the paper filler of the present invention may be subjected to a treatment for increasing the whiteness by a known method.

  According to the present invention, since the incinerated ash disposed as waste can be reused, the burden on the environment can be reduced. Moreover, since the process with respect to incineration ash is comparatively simple and few, this invention is advantageous from an energy and cost viewpoint, and can be implemented industrially simply.

Production of heatset offset printing paper Heatset offset printing paper can be produced using the papermaking filler of the present invention. The papermaking filler of the present invention can be used for papermaking using a general papermaking machine because it hardly wears the wire of the papermaking machine. In particular, a paper machine used to make offset printing paper is preferably a gap former, a hybrid former, an on-top former or the like having a double-side dewatering mechanism, but is not limited thereto.

  The pulp raw material of the heat-set type offset printing paper produced in the present invention is not particularly limited, and ground pulp (GP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), deinked pulp (DIP), softwood kraft pulp (NKP), hardwood kraft pulp (LKP), etc., as long as they are generally used as a papermaking raw material. Above all, it is desirable that deinked pulp is used more frequently from the environmental viewpoint. Specifically, the deinked pulp is 30% by weight, preferably 40% by weight, and more preferably 50% by weight or more based on the total pulp solid content. Of course, it is most preferable to use 100% by weight of deinked pulp.

  The papermaking filler of the present invention can be used alone or in combination with other papermaking fillers. When used in combination with other paper-making fillers, known fillers can be used alone or in appropriate combination of two or more. For example, calcium carbonate, calcium carbonate-silica composite, kaolin (filler kaolin, calcined kaolin) Etc.), talc, hydrous silicic acid (white carbon), hydrous silicate, magnesium carbonate, barium carbonate, zinc oxide, silicon oxide, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide and other inorganic fillers; vinyl chloride Organic fillers such as resins, polystyrene resins, urea / formalin resins, melamine resins, styrene / butadiene copolymer resins, phenol resins, plastic hollow particles, or organic / inorganic composite fillers can be used.

  The ash content in the paper is not particularly limited and is about 3% by weight or more based on the absolute dry weight of the paper, and the papermaking filler used in the present invention is 10% by weight or more, and further 15% by weight or more. Even in this case, generation of paper dust and printing plate wear during printing are suppressed, which is suitable for heat-set offset printing paper having a high ash content. Most of the ash content (inorganic content) in paper is derived from fillers added in the manufacture of paper and brought in by DIP which is a pulp raw material. In the present invention, the ratio of the paper filler used incineration ash as a raw material is 0.1 to 5% by weight, preferably 0.5 to 3% by weight, based on 100% by weight of the added filler. If the paper-making filler of the present invention is too much, the influence on the whiteness of the paper becomes large.

  When producing paper using the papermaking filler of the present invention, various papermaking chemicals can be used. Specifically, if necessary, the paper strength of polyacrylamide polymer, polyvinyl alcohol polymer, starch polymer (cationized starch, modified starch, etc.), urea / formalin resin, melamine / formalin resin, etc. is increased. Agent: Acrylamide / aminomethylacrylamide copolymer salt, starch polymer (cationized starch, modified starch, etc.), polyethyleneimine, polyethylene oxide, acrylamide / sodium acrylate copolymer, etc. Agents; aluminum sulfate (sulfuric acid band); water resistance agent; bulking agent; ultraviolet light inhibitor; printability improver; fading inhibitor and the like can be used. These auxiliary agents may be added to the incineration ash filler slurry of the present invention in advance and then applied to the paper machine, or may be applied separately to the incineration ash filler slurry of the present invention to the paper machine. .

  In the present invention, for the purpose of increasing the surface strength, a surface treatment agent mainly composed of a water-soluble polymer may be applied on the paper containing the papermaking filler. Examples of water-soluble polymers include starch, oxidized starch, esterified starch, etherified starch, cationized starch, enzyme-modified starch, aldehyde-modified starch, hydroxyethylated starch and other modified starches, carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, etc. Cellulose derivatives, modified alcohols such as polyvinyl alcohol and carboxyl-modified polyvinyl alcohol, styrene butadiene copolymers, polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, polyvinyl chloride, polyvinylidene chloride, polyacrylic acid esters, polyacrylamide, etc. And is applied in the form of an aqueous solution containing an adhesive or an aqueous latex. The surface treatment agent can contain a surface sizing agent such as styrene acrylic acid, styrene maleic acid, or an olefin compound for the purpose of increasing the size. Further, in the present invention, for the purpose of improving printability, a pigment coating layer may be provided by applying a coating liquid mainly composed of a pigment and an adhesive on a paper containing the papermaking filler. Good.

What is necessary is just to set the physical property of the heat set type | mold offset printing paper of this invention according to various uses. In the case of general printing paper, for example, the basis weight is 40 to 90 g / m ² , the Oken smoothness is 10 to 120 seconds, and the dynamic friction coefficient is about 0.3 to 0.7.

Physical property values Each characteristic value in the present invention is a value obtained by the following measuring method.
(1) Particle size distribution measurement (laser method): The particle size distribution is measured by a laser diffraction method. The sample slurry was dropped and mixed in pure water to which a dispersant (sodium hexametaphosphate) 0.2% by weight (based on the solid content of the sample) was added to form a uniform dispersion, and a laser particle size measuring instrument (equipment used: Malvern) The particle size is measured using a master sizer.
(2) Degree of wire wear: Wire wear is measured with an Einlehner AT1000 wear tester using a phosphor bronze wire disk (hereinafter referred to as wire). The wire used for measurement was washed in an ultrasonic bath for 5 minutes, then washed with ion-exchanged water, and further washed with acetone. This was dried at 105 ° C. for 1 hour or longer, allowed to cool in a desiccator, and then weighed with an accuracy of 0.1 mg. This wire was fixed to the bottom of the test cylinder, and the stirrer was lowered to contact the wire. A slurry having a concentration of 10% with ion-exchanged water was used as a measurement sample and injected into a test cylinder machine. In this state, the stirrer was rotated 174,000 to wear the wire. The wire after the abrasion test was washed again in an ultrasonic bath for 5 minutes, then washed with ion-exchanged water, and further washed with acetone. This was dried at 105 ° C. for 1 hour or longer, allowed to cool in a desiccator, and then weighed with an accuracy of 0.1 mg. The wire weight after the wear test was subtracted from the wire weight before the wear test to obtain the degree of wire wear (mg).
(3) Whiteness: The sample was placed in a ring-shaped measuring instrument so as to have a thickness that did not allow the measurement light to pass through the back side, and pelletized by applying a pressure of about 20 kg / cm ² . About this pellet, using Murakami Color Research Laboratory CMS-35SPX, the whiteness was measured under conditions including a D65 light source, a 10-degree field of view, and ultraviolet light.
(4) X-ray diffraction: The crystal composition of the sample was measured with an X-ray diffraction measurement apparatus (X'Pert PRO: manufactured by PANalytical).
(5) Elemental analysis: The elemental composition of the sample was measured with a fluorescent X-ray measurement apparatus (ED2000: manufactured by Oxford Instruments).

Evaluation of Paper Quality The paper quality of the heat-set type offset printing paper in the present invention is a value measured according to the method specified below.
(1) Basis weight: ISO536
(2) Ash content in paper: ISO 1762
(3) Whiteness: ISO 2470
(4) Opacity: ISO 2471
Printing Evaluation The printing evaluation of the heatset type offset printing paper in the present invention was carried out using a CTP output plate (ExThermoTP-R positive thermal plate manufactured by KODAK) on a Toshiba offset rotary press, with a printing speed of 700 rpm and a dampening film thickness. This is the printing workability and printing quality when 20,000 copies of black single color printing is performed using 0.7 μm heat setting ink (Toyo Ink LeoX).
(1) Measurement of the amount of paper dust: The paper dust deposited on the blanket after printing 20,000 copies was scraped, the weight was measured, and expressed in weight per 100 cm ² .
(2) Printing plate wear evaluation method: The image area (halftone dot density 100%) of the printing plate before printing and after printing 20,000 copies was measured with a reflective printing densitometer (Macbeth densitometer RD918). The concentration difference was calculated. The greater the density difference, the greater the damage to the image area, indicating that the plate is being worn.
(3) Ink fillability: The ink fillability was evaluated by visual observation of the black solid surface when printing 20,000 copies.
(4) Back-through: Back-through was evaluated by visually observing the solid surface of 20,000 copies printed from the back.

  Examples of the present invention will be specifically described below in comparison with comparative examples, but the present invention is not limited to these examples. In the description, “%” and “part” indicate “weight percent” and “part by weight” unless otherwise specified. In addition, the material addition rate indicates the solid content addition rate unless otherwise specified.

<Manufacture of paper fillers>
By the method shown below, paper filler was manufactured using incinerated ash as a raw material. As the raw material, sludge derived from the papermaking process (approximately 80% by weight sludge derived from the recycled paper recycling process, approximately 20% by weight sludge derived from papermaking white water) or coal was used. In addition, the physical property evaluation (particle size, wire wear degree, whiteness) of the incinerated ash material was carried out by the method described above.

[Paper filler A]
As a starting material, sludge derived from the papermaking process was used. This sludge was incinerated using a fluidized bed furnace at an oxygen concentration of 7%, a residence time of 2 seconds, and 770 ° C. to obtain 300 kg of incinerated ash. When this incinerated ash was measured, the average particle size was 230 μm and the whiteness was 51%.

  Add 2200 kg of water to 300 kg of the above incinerated ash, add 1% of solid sodium acrylate (Aron T-40: manufactured by Toa Gosei Co., Ltd.) as a dispersant to the incinerated ash, and thoroughly stir with an agitator Thus, an incineration ash slurry having a solid content concentration of 12% was obtained.

  Next, the slurry was pulverized using a sand grinder (grinding medium: 0.8 mm diameter glass beads). The pulverization treatment was performed for 3 hours 30 minutes by circulating the slurry between the holding tank and the pulverizer, and finally an incinerated ash material having an average particle size of 2.7 μm was obtained. While performing the pulverization step, sulfuric acid was gradually added for pH adjustment. Specifically, 97% sulfuric acid was added to the holding tank by a rotary pump, and the total amount of 97% sulfuric acid added was 24L. Sulfuric acid was added directly below the stirring blade of the agitator rotating at 1000 rpm so that the added sulfuric acid was sufficiently dispersed. The pH of the incinerated ash slurry after pH adjustment was 8.5.

  After removing coarse particles from the slurry using a 200-mesh sieve (aperture: 0.075 mm), no. Suction filtered using 2 filter papers. A part of the solid phase was dried under reduced pressure to obtain a sample for measuring whiteness. Further, a part of the filtered cake was redispersed in water at a concentration of 10% to obtain a sample for measuring the average particle diameter and wire wear. Furthermore, the remainder of the filtered cake was redispersed in water at a concentration of 1% and used as a papermaking sample. Moreover, according to the place estimated from the peak area of X-ray diffraction with respect to the gehlenite content of the comparative example 1 mentioned later, the gehlenite content of the said filler for paper manufacture was 20%.

[Paper filler B]
Incinerated ash was obtained from sludge from the papermaking process in the same manner as in Example 1. 300 kg of this incinerated ash (average particle size 230 μm, whiteness 51%) is added to 2200 kg of water, and sodium polyacrylate (Aron T-40: manufactured by Toa Gosei Co., Ltd.) as a dispersant is 1 in solid content with respect to the incinerated ash. % And the mixture was sufficiently stirred with an agitator to obtain an incinerated ash slurry having a solid content of 12%.

  Next, using this slurry, a grinding process was performed for 3 hours and 20 minutes using a sand grinder (grinding medium: 0.8 mm diameter glass beads) as the first stage grinding. The pulverization treatment was performed by circulating the slurry between the holding tank and the pulverizer to obtain an incinerated ash material having an average particle size of 2.9 μm. Next, using this slurry, a grinding process was performed for 1 hour 30 minutes using a horizontal bead mill (grinding medium: 0.5 mm zircon beads) as the second stage grinding. The pulverization process was performed by circulating the slurry between the holding tank and the pulverizer, and finally an incinerated ash material having an average particle diameter of 1.6 μm was obtained. Sulfuric acid was gradually added for the purpose of pH adjustment while performing the first and second pulverization steps. Specifically, 97% sulfuric acid was added to the holding tank by a rotary pump, and the total amount of 97% sulfuric acid added was 24L. Sulfuric acid was added directly below the stirring blade of the agitator rotating at 1000 rpm so that the added sulfuric acid was sufficiently dispersed. The pH of the incinerated ash slurry after pH adjustment was 8.5.

  After removing the coarse particles from the slurry using a 200 mesh sieve, Suction filtered using 2 filter papers. A part of the solid phase was dried under reduced pressure to obtain a sample for measuring whiteness. Further, a part of the filtered cake was redispersed in water at a concentration of 10% to obtain a sample for measuring the average particle diameter and wire wear. Further, the remainder of the filtered cake was redispersed in water at a concentration of 1% and used as a paper sample as a filler. Moreover, according to the place estimated from the peak area of X-ray diffraction with respect to the gehlenite content of the comparative example 1 mentioned later, the gehlenite content of the said filler for paper manufacture was 20%.

[Paper filler C]
A papermaking filler was produced and evaluated in the same manner as in Example 1 except that the pulverization time was 1 hour and 45 minutes, and finally an incinerated ash material having an average particle diameter of 7.8 μm was obtained.

[Paper filler D]
As the starting material, sludge from the same papermaking process as in Example 1 was used. This sludge was incinerated using a fluidized bed furnace at an oxygen concentration of 7%, a residence time of 2 seconds, and 730 ° C. to obtain 300 kg of incinerated ash. When the incinerated ash was measured, the average particle size was 205 μm and the whiteness was 53%.

  Add 2200 kg of water to 300 kg of the above incinerated ash, add 1% of solid sodium acrylate (Aron T-40: manufactured by Toa Gosei Co., Ltd.) as a dispersant to the incinerated ash, and thoroughly stir with an agitator Thus, an incineration ash slurry having a solid content concentration of 12% was obtained.

  Next, the slurry was pulverized using a sand grinder (grinding medium: 0.8 mm diameter glass beads). The pulverization treatment was performed for 3 hours 30 minutes by circulating the slurry between the holding tank and the pulverizer, and finally an incinerated ash material having an average particle diameter of 2.5 μm was obtained. While performing the pulverization step, sulfuric acid was gradually added for pH adjustment. Specifically, 97% sulfuric acid was added to the holding tank by a rotary pump, and the total amount of 97% sulfuric acid added was 24L. Sulfuric acid was added directly below the stirring blade of the agitator rotating at 1000 rpm so that the added sulfuric acid was sufficiently dispersed. The pH of the incinerated ash slurry after pH adjustment was 8.5.

  After removing the coarse particles from the slurry using a 200 mesh sieve, Suction filtered using 2 filter papers. A part of the solid phase was dried under reduced pressure to obtain a sample for measuring whiteness. Further, a part of the filtered cake was redispersed in water at a concentration of 10% to obtain a sample for measuring the average particle diameter and wire wear. Further, the remainder of the filtered cake was redispersed in water at a concentration of 1% and used as a filler as a papermaking sample. Moreover, according to the place estimated from the peak area of X-ray diffraction with respect to the gehlenite content of the comparative example 1 mentioned later, the gehlenite content of the said filler for paper manufacture was 13%.

[Paper filler E]
Coal was used as a starting material. The coal was incinerated using a burner furnace at an oxygen concentration of 4%, a residence time of 2 seconds, and 750 ° C. to obtain 300 kg of incinerated ash. When this incinerated ash was measured, the average particle size was 145 μm and the whiteness was 21%.

  Add 2200 kg of water to 300 kg of the above incinerated ash, add 1% of solid sodium acrylate (Aron T-40: manufactured by Toa Gosei Co., Ltd.) as a dispersant to the incinerated ash, and thoroughly stir with an agitator Thus, an incineration ash slurry having a solid content concentration of 12% was obtained.

  Next, the slurry was pulverized using a sand grinder (grinding medium: 0.8 mm diameter glass beads). The pulverization treatment was performed by circulating the slurry between the holding tank and the pulverizer for 3 hours and 10 minutes, and finally an incinerated ash material having an average particle size of 2.6 μm was obtained. While performing the pulverization step, sulfuric acid was gradually added for pH adjustment. Specifically, 97% sulfuric acid was added to the holding tank by a rotary pump, and the total amount of 97% sulfuric acid added was 24L. Sulfuric acid was added directly below the stirring blade of the agitator rotating at 1000 rpm so that the added sulfuric acid was sufficiently dispersed. The pH of the incinerated ash slurry after pH adjustment was 8.5.

  After removing the coarse particles from the slurry using a 200 mesh sieve, Suction filtered using 2 filter papers. A part of the solid phase was dried under reduced pressure to obtain a sample for measuring whiteness. Further, a part of the filtered cake was redispersed in water at a concentration of 10% to obtain a sample for measuring the average particle diameter and wire wear. Further, the remainder of the filtered cake was redispersed in water at a concentration of 1% and used as a filler as a papermaking sample. Moreover, according to the place estimated from the peak area of an X-ray diffraction with respect to the gehlenite content of the comparative example 1 mentioned later, the gehlenite content of the said filler for paper manufacture was 8%.

[Paper Filler F] (Comparative Example)
As the starting material, sludge derived from the same papermaking process as in Example 1 was used. The sludge was incinerated using a fluidized bed furnace at an oxygen concentration of 7%, a residence time of 2 seconds, and 860 ° C. to obtain 300 kg of incinerated ash. When this incinerated ash was measured, the average particle size was 220 μm and the whiteness was 48%.

  Add 2200 kg of water to 300 kg of the above incinerated ash, add 1% of solid sodium acrylate (Aron T-40: manufactured by Toa Gosei Co., Ltd.) as a dispersant to the incinerated ash, and thoroughly stir with an agitator Thus, an incineration ash slurry having a solid content concentration of 12% was obtained.

  Next, the slurry was pulverized using a sand grinder (grinding medium: 0.8 mm diameter glass beads). The pulverization was performed by circulating the slurry between the holding tank and the pulverizer for 3 hours and 30 minutes, and finally an incinerated ash material having an average particle diameter of 2.8 μm was obtained. While performing the pulverization step, sulfuric acid was gradually added for pH adjustment. Specifically, 97% sulfuric acid was added to the holding tank by a rotary pump, and the total amount of 97% sulfuric acid added was 24L. Sulfuric acid was added directly below the stirring blade of the agitator rotating at 1000 rpm so that the added sulfuric acid was sufficiently dispersed. The pH of the incinerated ash slurry after pH adjustment was 8.5.

  After removing the coarse particles from the slurry using a 200 mesh sieve, Suction filtered using 2 filter papers. A part of the solid phase was dried under reduced pressure to obtain a sample for measuring whiteness. Further, a part of the filtered cake was redispersed in water at a concentration of 10% to obtain a sample for measuring the average particle diameter and wire wear. Further, the remainder of the filtered cake was redispersed in water at a concentration of 1% and used as a filler as a papermaking sample.

[Paper Filler G] (Comparative Example)
A paper filler was produced in the same manner as in Example 2 except that the grinding time by the sand grinder was shortened to 2 hours and 50 minutes, and finally an incinerated ash material having an average particle size of 7.3 μm was obtained.

  Table 1 shows various performances of the papermaking filler. Compared with the paper-making fillers FG (comparative examples), the paper-making fillers A to E obtained by incinerating the raw materials at 700 to 800 ° C. were able to greatly improve the degree of wire wear. In particular, when comparing the paper filler A and the paper filler F, they are the same combustion raw material, and the average particle size after pulverization is 2.7 μm for the paper filler A and 2.8 μm for the paper filler F, which is about 4 However, there is a significant difference in the degree of wire wear, and the papermaking filler A treated at 770 ° C and the papermaking filler F · G treated at 860 ° C have an opening of about 3.1 times. was there. Such a significant difference in the degree of wire wear at the heat treatment temperature of about 800 ° C. is a knowledge that has not been known so far, and is an effect found by the present invention.

  Regarding the whiteness, there was almost no change before and after the pulverization treatment. In the present invention, it is not essential to include a step for increasing the whiteness. Actually, the papermaking fillers A to E are not subjected to such a process. However, in order to increase the added value as a papermaking filler, the papermaking filler of the present invention may be subjected to a treatment for increasing the whiteness by a known method.

  Table 2 shows the results of analyzing the elemental composition of the various incinerated ash materials obtained by fluorescent X-rays. Since the papermaking fillers A to C, F, and G use the same papermaking process-derived sludge, the elemental composition is also the same. The papermaking filler D also uses a papermaking process-derived sludge and has a composition similar to that of the papermaking fillers A to C, F, and G. On the other hand, since the filler E for papermaking is coal incineration ash, it has an element composition different from these.

  Furthermore, the result of having analyzed the various incinerated ash materials obtained by X-ray diffraction is shown in FIG. Compared with the papermaking fillers F and G heat-treated at 860 ° C., the papermaking fillers A to E heat-treated at 730 to 770 ° C. had small peaks derived from gehlenite, and the formation of galenite having high hardness was suppressed.

The incinerated ash material of the present invention is particularly suitable as a filler for papermaking because it is excellent in wire wear and hardly damages the papermaking wire when internally added in the papermaking process.
<Manufacture of heatset offset printing paper using papermaking filler>
By the following method, a heat-set type offset printing paper was produced by internally adding the papermaking filler of the present invention. Paper quality evaluation (basis weight, ash content, whiteness, opacity) and printing evaluation (paper powder amount, printing plate wear resistance, ink fillability, back-through) were carried out by the methods described above. The results are shown in Table 3.

[Example 1]
As raw material pulp for papermaking, deinked pulp (freeness 200 ml, ash content 10%, hereinafter abbreviated as DIP), thermomechanical pulp (freeness 100 ml, hereinafter abbreviated as TMP), hardwood kraft pulp (freeness 500 ml) , Hereinafter referred to as LKP)) in a pulp slurry mixed at a blending ratio of 50:10:40, 1% sulfuric acid band, 0.03% internal sizing agent, and internal paper strength agent per absolute dry weight of pulp. 0.03%, 15% light calcium carbonate (particle size 2.1μm) as filler, 2% paper filler A, 300ppm yield improver, twin wire paper machine, 1000m / min. The paper was neutralized so that the basis weight was 60 g / m ² , and a heat-set offset printing paper was made.

[Example 2]
The same procedure as in Example 1 was performed except that the papermaking filler B was added instead of the papermaking filler A.

[Example 3]
The same procedure as in Example 1 was performed except that the papermaking filler C was added instead of the papermaking filler A.

[Example 4]
The same procedure as in Example 1 was performed except that the papermaking filler D was added instead of the papermaking filler A.

[Example 5]
The same procedure as in Example 1 was performed, except that papermaking filler E was added instead of papermaking filler A.

[Comparative Example 1]
The same procedure as in Example 1 was carried out except that light calcium carbonate (particle size 2.1 μm) was added in an amount of 17% by weight per pulp dry weight without using the papermaking filler A.

[Comparative Example 2]
The same procedure as in Example 1 was performed except that the papermaking filler F was added instead of the papermaking filler A.

[Comparative Example 3]
The same procedure as in Example 1 was carried out except that the papermaking filler G was added instead of the papermaking filler A.

Table 3 shows the performance of the papermaking fillers obtained in Production Examples A to G of the papermaking filler, and the results of the paper quality and printing evaluation of the printing paper obtained in Examples 1 to 5 and Comparative Examples 1 to 3. Indicates. From these results, the following can be said.
(1) Paper-made fillers A to E were obtained by incineration of raw materials at 700 to 800 ° C., compared with paper-made fillers F and G, thereby greatly improving the degree of wire wear. . In particular, when comparing the papermaking fillers A and F, the combustion raw materials are the same, and the average particle size after pulverization is only about 4%, which is 2.7 μm for the papermaking filler A and 2.8 μm for the papermaking filler F. Despite no change, a noticeable difference was observed in the degree of wire wear, and the papermaking filler A treated at 770 ° C. and the papermaking filler F treated at 860 ° C. had a difference of about 3.1 times. From this, it can be seen that there is a significant difference in the degree of wire wear at the heat treatment temperature of about 800 ° C.
(2) Regarding the whiteness of the papermaking filler, the papermaking fillers A to E were not subjected to a special process for increasing the whiteness, but there was no problem.
(3) When the obtained paper filler was analyzed by X-ray diffraction, the paper-made fillers A to F heat treated at 730 to 770 ° C. compared to the paper fillers F and G heat treated at 860 ° C. The origin peak was small, and the production of gehlenite was suppressed (FIG. 1).
(4) When the papermaking fillers A to E of the present invention are used (Examples 1 to 5), the printing paper is printed in the same manner as when the papermaking filler obtained from incinerated ash is not used (Comparative Example 1). It was possible to manufacture without problems. Compared to Comparative Example 1 in which calcium carbonate is used for the total amount of filler, even in Examples 1 to 5 in which a part of the filler is replaced with a paper filler obtained from incinerated ash, both whiteness and opacity are particularly low. It can be said that the quality of the printing paper is maintained.
(5) Comparing Examples 1 to 5 with paper-filling fillers F and G heat-treated at 860 ° C. when 20,000 copies were printed (Comparative Examples 2 and 3) The amount of powder and the wear of the printing plate were remarkably deteriorated, and the ink setting property was also inferior.
(6) When the printing evaluation results of Example 1 and Comparative Example 2 are compared, the starting materials for both papermaking fillers are the same, and the average particle size after pulverization is 2.7 μm in Example 1 and 2 in Comparative Example 1. While it was almost the same as .8 μm, a large difference was observed in the amount of paper dust, the abrasion resistance of the printing plate, and the ink setting property.

Claims (6)

A raw material comprising at least one selected from the group consisting of papermaking sludge, coal, paper-containing waste, biomass, and composite fuel at 700 to 800 ° C. for 0.1 to 60 seconds, 0.1 to 15% A heatset offset printing paper containing a papermaking filler having a whiteness of 10 to 60% obtained by incineration at an oxygen concentration and having an ash content of 10% by weight or more . The printing paper according to claim 1, wherein the raw material is papermaking sludge and / or coal. The printing paper according to claim 1 or 2, wherein the paper filler is obtained by incinerating the raw material in an internal combustion furnace. The printing paper in any one of Claims 1-3 whose average particle diameter of the said filler for paper manufacture is 0.1-10 micrometers. The papermaking filler disperses the incinerated ash obtained by incineration of the raw materials into a slurry, and wet pulverizes while adjusting the pH to 7 to 10 by adding sulfuric acid and / or sulfate to the incinerated ash slurry. The printing paper in any one of Claims 1-4 obtained by processing. The printing paper in any one of Claims 1-5 whose solid content concentration of the said incineration ash slurry is 1 to 50%.

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