JP2006257620A - Newsprint paper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide high-quality newsprint paper having high whiteness with a small amount of impurities and excellent inking properties, slightly deteriorating tearing strength and stiffness in spite of bulkiness though DIP (de-inked pulp) is highly compounded. <P>SOLUTION: The newsprint paper comprises the DIP obtained by generating bubbles according to cavitation, bringing the bubbles into contact with a waste paper pulp suspension and peeling contaminants sticking to the pulp fibers and ash as a raw material. Book printing paper can be obtained by generating the bubbles according to the cavitation, bringing the bubbles into contact with the pulp suspension, treating the pulp suspension and thereby using the resultant pulp having the regulated freeness of the pulp as a pulp raw material for the newsprint paper. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to newspaper printing paper. More specifically, the present invention relates to a newspaper printing paper manufactured using pulp processed by contacting bubbles generated by cavitation.

  In recent years, recycling of waste paper has been strongly demanded from the viewpoint of resource saving or environmental protection on a global scale, and expanding the range of use has become a very important issue. On the other hand, conventional recycled pulp was often used for newspaper and magazine paper, but in recent years, waste paper has been processed to a higher degree, with high whiteness and little residual ink, in order to develop various applications. There is a demand for producing recycled pulp (hereinafter referred to as deinked pulp).

  The method for recycling used paper generally comprises a step of peeling ink from pulp fibers and a step of removing the peeled ink. More specifically, in the pulper, the exfoliation and miniaturization of the ink from the pulp fiber is promoted by hydrodynamic shear force or frictional force between the pulp fibers, and then the ink is removed by flotation and / or washing. The way to do it is mainstream. In this process, if necessary, deinking chemicals such as sodium hydroxide, sodium silicate, oxidizing bleaching agent and / or reducing bleaching agent, deinking agent, etc. may be added to treat waste paper at an alkaline pH value. It is common. When waste paper is processed at a higher level, the ink remaining on the pulp fibers that could not be removed by the above treatment is peeled off.For example, after the ink peeling step or the ink removing step, the ink is further peeled off and refined by mechanical force. A method of promoting, a method of removing ink thereafter (see Patent Document 1), and the like are employed.

  However, with the diversification of used paper, the inclusion of offset ink that has deteriorated with time and advanced oxidative polymerization, toner ink that has been heat-sealed to pulp fibers, UV resin ink that has been cured by processing during printing, and the like has increased. In the used paper recycling method, there is a problem that the peel strength is insufficient, the unpeeled ink remains, and the finished pulp quality is significantly lowered. As a countermeasure, a method of processing at a higher mechanical load or higher temperature, or a method of adding more chemicals such as alkali or deinking agent is adopted, but due to an increase in mechanical load, Reduced paper strength (particularly reduced tear strength) due to shortening of pulp fibers and increase in fine fibers, reduced dimensional stability due to pulp fiber twist, increased paper curl, increased steam cost and chemical costs due to high temperature The cost of recycled pulp due to the problem has been a problem.

  In addition, there is a method that repeats a plurality of times until the desired pulp quality is obtained, but an extremely large capital investment is required, and the ink removing step consisting of the mechanical force and the flotation and / or washing are repeated. In addition, since the drainage load is increased, the introduction is not proceeding with great demerits in terms of cost, energy and environment. For this reason, in particular, toner prints and UV resin ink prints are used only for paperboards and household papers, and can be actively used as waste paper materials for paper such as printing papers, information papers, and newspaper printing papers. There wasn't.

  In addition, the number of recyclings of pulp fiber itself has increased with the improvement in the waste paper utilization rate, and reports by Okayama et al. (Takayuki Okayama, 7th Pulp Basic Course, Waste Paper Pulp (Part 2), Paper Pulp Technology Association, p101-111, 2002) ) The pulp fiber is severely damaged. Pulp fibers are known to have a significant decrease in hydrogen bond-forming ability due to heat drying. When reclaiming waste paper once dried, beating it with a refiner or the like to make up for this, make the pulp fibers fluffy. It is necessary to improve the hydrogen bond forming ability. However, in this process, the internal structure of the pulp fiber is significantly damaged, resulting in a layered or annular cracked structure. The pulp fibers in such a state are considered to be easily cut by contact between the fibers by rubbing between the fibers due to mechanical force in the recycling process of the waste paper and stirring blades, and promote shortening of the pulp fibers. ing. As described above, in the conventional technology, in order to produce high-quality pulp from diversified waste paper, it is inevitable that the pulp fiber is damaged, or the energy consumption and the wastewater treatment cost are increased. .

  On the other hand, not only when deinked pulp is produced from the above-mentioned waste paper, but for the purpose of improving the smoothness of the paper surface and improving the paper strength, conventionally, the pulp is beaten using mechanical force. The pulp fiber has been modified. This beating process increases the shortened pulp fibers and fine fibers, so that the paper layer becomes dense and the smoothness of the paper is improved, and the interfiber bonding area is increased by fluffing of microfibrils on the surface of the pulp fibers. The effect of increasing the paper strength was obtained. However, in this beating treatment, damage due to cutting of the pulp fiber itself occurs, so that a decrease in paper strength (particularly a decrease in tear strength) occurs due to a decrease in pulp fiber length. In addition, the paper layer becomes dense, but there is also a problem that the bulk of the paper is reduced (density is increased).

  In this way, the conventional deinked pulp manufacturing technology and pulp beating technology impose a mechanical load on the entire pulp fiber, so to improve the pulp quality, damage or shortening of the pulp fiber or increase in the cost of added chemicals is required. It was inevitable.

  In the following Ukrainian non-patent documents (see Non-patent documents 1, 2, and 3), cavitation is used for the production of used paperboard pulp, but it does not perform deinking or beating as in the present invention. . In addition, Patent Document 2 discloses a pulp processing method using cavitation by passing a pulp suspension through a reactor having a specific shape. In this method, ink is sufficiently peeled and removed. It was difficult to do.

  As a recent technological trend in the field of newspaper printing paper, first of all, an increase in the ratio of used paper to newspaper printing paper can be mentioned against the background of improvement of environmental awareness and cost reduction. The ratio of used paper is increasing year by year, and it is not uncommon for newspaper printing paper to exceed 70%. As described above, deinked pulp obtained by the conventional technology has shortened pulp fiber, increased fine fiber content, twisted pulp fiber, increased unpeeled ink, decreased whiteness, etc. There was a quality problem. When this conventional deinked pulp is highly blended, the paper strength (particularly tear strength) and stiffness (paper stiffness) of the resulting newspaper printing paper will be reduced, so it will be necessary to blend high-concentration softwood kraft pulp. In other words, there are problems such as an increase in manufacturing cost, and a problem such as a decrease in dimensional stability and an increase in curl, and an increase in the whiteness of newspaper printing paper. Newspaper paper tear strength is one of the important paper quality items.

Secondly, it is possible to reduce the weight (low basis weight) of newspaper printing paper against the background of demands for reducing pulp resource consumption and reducing transportation costs. At present, some major users are using 40.5 g / m ² ultra-lightweight newspapers. However, the weight of newspaper printing paper tends to decrease due to the weight reduction, which has been a major limitation in promoting weight reduction.

  Thirdly, double-sided color printing has become possible with the advent of a tower press-type offset printing press, so it can be mentioned that the increase in the color surface of newspapers has been advancing rapidly in recent years. Nearly half of the pages are expected to become color in the near future, and a clear color printing surface is required. Against this background, demand for the quality of newsprint for offset printing is increasing year by year. Above all, the demand for ink fillability is high. As the most common method for improving the ink deposition property, a calendar process for paper is exemplified. By applying the calendering process, the smoothness of the paper surface can be improved and the ink transfer from the blanket of the offset printing machine to the paper can be improved. When the smoothness of the paper is improved, the paper layer is greatly crushed and the paper thickness is reduced. This reduction in paper thickness has the problem of lowering paper stiffness.

Japanese Patent No. 3191828 JP 49-51703 R.A.SoloИitsyИ et al., Bum Prom-st ', 1987 (6), 22 R.A.SoloИitsyИ et al., Bum Prom-st ', 1987 (1), 25 R.A.SoloИitsyИ et al., Bum Prom-st ', 1986 (7), 24

  The first problem to be solved by the present invention is that even if it contains a high amount of deinked pulp (hereinafter referred to as DIP), it is bulky and has little reduction in tearing strength and rigidity, and there are few impurities and whiteness. Is to provide high-quality newspaper printing paper with high ink-inking properties. A second problem is to provide a newspaper printing paper that is bulky but has a small decrease in rigidity and is excellent in ink deposition.

  In the production of DIP, the present inventors pay attention to the fact that most of the ink adheres to the surface of the pulp fiber and / or coating layer. As a result of earnest research on the method of peeling the ink by selectively applying a load to the pulp fiber surface, bubbles were generated by cavitation, and the DIP processed by contacting it with the pulp suspension was , Damage and shortening of the pulp fiber itself is suppressed, peeling and miniaturization of the ink adhering to the pulp fiber surface is promoted, and a high quality product with high whiteness and little residual ink can be obtained. By using the DIP as a pulp raw material for printing paper, it is bulky but has little decrease in tear strength and rigidity, has few impurities, has high whiteness, and has high ink quality. It found to be able to produce newsprint, and completed the newsprint paper of the invention, leading to solve the first problem.

  In addition, the present inventors pay attention to the fact that the bulk of the pulp fiber itself is most reduced during the mechanical beating process, and selectively applies a load to the surface of the pulp fiber to promote fiber damage and internal fibrillation. As a result of intensive research on how to obtain a bulky pulp by controlling the freeness without reducing the bulk of the pulp fiber, bubbles are generated by cavitation and contacted with the pulp suspension. The freeness of the fine bubbles can be adjusted by adjusting the drainage without damaging the bulk of the pulp fiber, and the adjusted pulp can be used as a raw material for newspaper printing paper. As a result, it was found that a high-quality newspaper printing paper having high ink quality and a small decrease in stiffness can be produced while being bulky, and the newspaper printing paper of the present invention was completed. It has led to solve the second problem.

  That is, the present invention is a newspaper printing paper containing pulp that has been processed by generating bubbles by cavitation and contacting it with a pulp suspension.

  The first effect of the present invention is that the pulp from which contaminants adhering to the surface of the pulp fiber are removed by cavitation treatment is used as a raw material pulp for newspaper printing paper, so that it is bulky despite high DIP blending. On the other hand, it is possible to produce high-quality newspaper printing paper with little reduction in tearing strength and stiffness, few impurities, high whiteness, and excellent ink deposition. The second effect of the present invention is that, by using a pulp whose degree of drainage is adjusted by suppressing pulp fiber damage by cavitation treatment as a raw material pulp for newsprint paper, there is little decrease in stiffness while being bulky. The effect of being excellent in inking property and being able to produce newspaper printing paper with various quality improvements according to the type of cavitation treated pulp to be blended is obtained.

  Conventionally, the raw material pulp used in newspaper printing paper is chemical pulp (conifer bleached kraft pulp (NBKP) or unbleached kraft pulp (NUKP), hardwood bleached kraft pulp (LBKP)) or unbleached kraft. Pulp (LUKP, etc.), mechanical pulp (groundwood pulp (GP), refiner mechanical pulp (RGP), thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), etc.), DIP mixed in any proportion in use. In the newspaper printing paper of the present invention, the type of pulp to be treated with bubbles generated by cavitation is not particularly limited, and the above-mentioned various raw pulps, waste paper pulp, and the like can be used after being subjected to cavitation treatment. All types of pulp may be cavitation-treated and blended to make paper, or only specific types of pulp may be cavitation-treated and blended to make paper. Cavitation treatment may be used for blending and paper making. Non-wood fibers can also be used after cavitation treatment.

  The cavitation-treated pulp used in the newspaper printing paper of the present invention generates bubbles by cavitation and treats this by contacting the pulp suspension, thereby removing contaminants such as ink adhering to the pulp fiber. Pulp removed and / or pulp prepared to the desired freeness.

  Cavitation used for processing raw material pulp of the newsprint paper of the present invention will be described. Cavitation, as described in Kato's book (edited by Yoji Kato, new edition of Cavitation Basics and Recent Advances, Tsuji Shoten, 1999), cavitation bubbles, when collapsed, has a high impact on several Gpa in a local area of several μm. Generates force, and the temperature rises to several thousand degrees when viewed microscopically by adiabatic compression when bubbles collapse. As a result, when cavitation occurs, the temperature increases. From these facts, cavitation has been a technical problem to be solved because it causes damages such as damage, vibration and performance degradation to the fluid machine. In recent years, research on cavitation has progressed rapidly, and it has become possible to control the cavitation generation region and impact force with high accuracy using the hydrodynamic parameters of the cavitation jet as operating factors. As a result, it is beginning to be expected to effectively utilize the powerful energy by controlling the bubble collapse impact force. Therefore, it has become possible to control cavitation with high precision by performing operations and adjustments based on hydrodynamic parameters. This shows that it is possible to maintain the stability of the technical effects, and not by cavitation that causes uncontrollable harm that naturally occurs in fluid machinery, but by controlled cavitation. It is a feature of cavitation in the present invention to actively introduce the generated bubbles into the pulp suspension and effectively use the energy.

  Examples of the cavitation generating means in the present invention include, but are not limited to, a method using a liquid jet, a method using an ultrasonic transducer, a method using an ultrasonic transducer and a horn-shaped amplifier, and a method using laser irradiation. It is not a thing. Preferably, the method using a liquid jet has a high action effect on contaminants such as ink because the cavitation bubble generation efficiency is high and a cavitation bubble cloud having a stronger collapse impact force is formed. The cavitation generated by the above method is clearly different from cavitation that causes uncontrollable harm that naturally occurs in conventional fluid machines.

  The liquid jet is a jet of fluid in which solid particles or gas are dispersed or mixed in the liquid or liquid, and refers to a liquid jet containing slurry or bubbles of pulp or inorganic particles. The gas here may include bubbles due to cavitation.

  Since cavitation occurs when a liquid is accelerated and the local pressure is lower than the vapor pressure of the liquid, flow rate and pressure are particularly important. From this, the basic dimensionless number representing the cavitation state, the cavitation number σ, is defined as follows (edited by Yoji Kato, new edition of cavitation basics and recent advances, Tsuji Shoten, 1999).

（p_∞：一般流の圧力、U_∞：一般流の流速、p_v：流体の蒸気圧、ρ：密度）

(P _∞ : general flow pressure, U _∞ : general flow velocity, p _v : fluid vapor pressure, ρ: density)

Here, a large number of cavitations indicates that the flow field is in a state where cavitation is difficult to occur. In particular, when cavitation is generated through a nozzle or orifice tube such as a cavitation jet, the cavitation number σ is calculated from the following equation (from the nozzle upstream pressure p ₁ , the nozzle downstream pressure p ₂ , and the saturated vapor pressure p _{v of the} sample water: 2) In the cavitation jet, the pressure difference between p ₁ , p _{2 and} p _v is large and p ₁ >> p ₂ >> p _v. Therefore, the cavitation number σ is (H. Soyama, J. Soc. Mat. Sci. Japan, 47 (4), 381 1998).

  The cavitation condition in the present invention is preferably such that the above-mentioned cavitation number σ is 0.001 or more and 0.5 or less, preferably 0.003 or more and 0.2 or less, and particularly preferably 0.01 or more and 0.1 or less. When the cavitation number σ is less than 0.001, the effect is small because the pressure difference with the surroundings when the cavitation bubbles collapse is low, and when it is greater than 0.5, the flow pressure difference is low and cavitation is difficult to occur. .

  In addition, when cavitation is generated by injecting the injection liquid through the nozzle or Ophiris tube, the pressure of the injection liquid (upstream pressure) is desirably 0.01 MPa or more and 30 MPa or less, and 0.7 MPa or more and 15 MPa or less. Is preferable, and 2 MPa or more and 10 MPa or less is particularly preferable. When the upstream pressure is less than 0.01 MPa, it is difficult to produce a pressure difference with the downstream pressure, and the effect is small. On the other hand, when the pressure is higher than 30 MPa, a special pump and a pressure vessel are required, and energy consumption increases, which is disadvantageous in terms of cost. On the other hand, the pressure in the container (downstream pressure) is preferably 0.05 MPa or more and 0.3 MPa or less in static pressure. Moreover, the pressure ratio between the pressure in the container and the pressure of the spray liquid is preferably in the range of 0.001 to 0.5.

  The jet velocity of the jet liquid is preferably in the range of 1 m / second to 200 m / second, and preferably in the range of 20 m / second to 100 m / second. When the jet velocity is less than 1 m / sec, the effect is weak because the pressure drop is low and cavitation hardly occurs. On the other hand, if it is higher than 200 m / sec, a high pressure is required and a special device is required, which is disadvantageous in terms of cost.

  In the present invention, the cavitation treatment can be performed in any container such as a tank or in a pipe, but is not limited thereto. Further, although it is possible to perform processing by one pass, the effect can be further increased by circulating the required number of times. Furthermore, it can be processed in parallel or in permutation using a plurality of generating means.

  The jet for generating cavitation may be made in a container open to the atmosphere such as a pulper, but is preferably made in a pressure vessel in order to control cavitation.

  In the method of generating cavitation by the liquid jet in the present invention, for the pulp suspension, for example, distilled water, tap water, industrial water, reused water recovered in the papermaking process, pulp squeezed water, white water, Pulp suspension, alcohol or the like can be sprayed, but is not limited thereto. Preferably, by injecting the pulp suspension itself, in addition to the effect of cavitation generated around the jet, the hydrodynamic shear force when jetting from the orifice at high pressure can be obtained, so that a greater effect is exhibited. To do. In addition, when using a pulp suspension as an injection liquid, it is also possible to circulate and process the whole quantity made into a process target.

  When processing by generating cavitation with a liquid jet, the solid content concentration of the pulp suspension to be processed is preferably 5% by weight or less, more preferably 3% by weight or less, and still more preferably 0.1 to 1.5% by weight. It is preferable from the point of bubble generation efficiency to process in the range of%.

  The pH of the pulp suspension during the treatment is preferably pH 1 to 13, more preferably pH 3 to 12, and further preferably pH 4 to 11. If the pH is less than 1, corrosion of the apparatus becomes a problem, which is disadvantageous from the viewpoint of material and maintenance. On the other hand, if the pH exceeds 13, an alkali burn of the pulp fiber occurs and the whiteness decreases, which is not preferable. Alkaline conditions are desirable because pulp fibers have better swelling properties and increase the amount of OH active radicals produced.

  In the present invention, by increasing the jetting pressure of the liquid, the flow rate of the jetting liquid is increased and more powerful cavitation is generated. Further, by pressurizing the container for storing the liquid to be ejected, the pressure in the region where the cavitation bubbles collapse is increased, and the pressure difference between the bubbles and the surroundings is increased, so that the bubbles collapse violently and the impact force increases. Here, the jet liquid refers to a liquid ejected from an orifice at a high pressure, and the liquid to be ejected refers to a liquid ejected in a container or piping. Cavitation is affected by the amount of gas in the liquid, and when there is too much gas, collision and coalescence of bubbles occur, so that the impact force is weakened because a collapse effect is absorbed by other bubbles. Therefore, the treatment temperature must be not lower than the melting point and not higher than the boiling point because it is affected by dissolved gas and vapor pressure. When the liquid uses water as a medium, a high effect can be obtained by setting the temperature preferably in the range of 0 to 80 ° C., more preferably 10 to 60 ° C. Generally, the impact force is considered to be maximum at the midpoint between the melting point and the boiling point, so in the case of an aqueous solution, the optimum temperature is around 50 ° C, but it is not affected by the vapor pressure even at lower temperatures. Therefore, a high effect can be obtained within the above range. A temperature higher than 80 ° C. is not suitable because the pressure resistance of the pressure vessel for generating cavitation is remarkably lowered, and the vessel is likely to be damaged.

  In the present invention, the energy required to generate cavitation can be reduced by adding a substance such as a surfactant that lowers the surface tension of the liquid. Substances to be added include known or novel surfactants, for example, nonionic surfactants such as fatty acid salts, higher alkyl sulfates, alkylbenzene sulfonates, higher alcohols, alkylphenols, alkylene oxide adducts such as fatty acids, and the like. Examples include, but are not limited to, ionic surfactants, cationic surfactants, amphoteric surfactants, and organic solvents. These may be a single component or a mixture of two or more components. The addition amount may be an amount necessary for reducing the surface tension of the jet liquid and / or the liquid to be jetted. Further, the addition place may be any place in the process before the place where cavitation is generated, and when the liquid is circulated, it may be after the place where cavitation is generated.

  The newspaper printing paper according to the first aspect will be described below. The newspaper printing paper of the present invention contains DIP in which bubbles generated by cavitation are brought into contact with the waste paper pulp suspension to remove contaminants adhering to pulp fibers and ash. The used paper is a newspaper, a flyer, a paper-based magazine, a coated paper-based magazine, heat-sensitive / pressure-sensitive paper, imitation / color-quality paper, copy paper, computer output paper, or a mixed old paper thereof. In addition, used newspapers such as used newspapers that have deteriorated over time in summer and the like, paper magazines, and used office papers including toner prints can also be used. Furthermore, those in which contraindicated products such as laminated paper and paper printed with UV resin ink are mixed in the above-mentioned waste paper can be used. Contraindicated products refer to Class A and Class B as defined by the Waste Paper Recycling Promotion Center (Edited by the Waste Paper Recycling Promotion Center, Waste Paper Handbook 1999, p.4). Used office paper refers to all high-quality office waste paper defined by the Waste Paper Recycling Promotion Center (Waste Paper Handbook 1999, p.3). It is not limited. As inks other than toner contained in waste paper, known printing inks (edited by the Japan Printing Society, “Printing Engineering Handbook”, Gihodo, p.606, 1983), non-impact printing inks (“latest and special function inks”, CMC , P.1, 1990). Non-heated penetrating drying offset inks used in newspapers and magazines include known offset inks for newspapers and newspapers (Akiyuki Goto, Journal of Japan Printing Society, 38 (5), 7, (2001), etc.) Although it is mentioned, it is not limited to these.

  Any pulp contained in the above various waste papers can be used as the DIP of the newsprint paper of the present invention after removing contaminants by cavitation treatment. Moreover, there is no restriction | limiting in particular about the ratio of the pulp fiber and ash content in this DIP. Ash refers to inorganic particles in general and is a substance that remains when paper is incinerated, such as fillers added internally during paper manufacture or coated pigments.For example, calcium carbonate, talc, kaolin, Examples thereof include crystalline silica, titanium dioxide, and calcium sulfate.

  High quality by generating cavitation bubbles in the process of recycling used paper, bringing this into contact with the used paper pulp suspension to remove contaminants adhering to pulp fibers and ash, and removing the removed contaminants This contaminant refers to foreign matter adhering to pulp fibers and ash. For example, in addition to the above inks, fluorescent dyes and general dyes, paints and natural or synthetic polymers Examples thereof include coating layer residues such as substances, processed layer residues such as laminates, adhesives and pressure-sensitive adhesives, and sizing agents. Further, a yield improver, a freeness improver, a paper strength enhancer, an internal sizing agent, an internal additive for paper making such as a dye, and the like, which are internally added when paper is made, may be mentioned. Of these, ink is a major contaminant.

Cavitation treatment can be applied anywhere in the deinking process used to recycle waste paper, which consists of an ink peeling process with mechanical force such as high-density pulper and kneader, and an ink removal process by flotation and / or washing. it can. Further, a cavitation treatment may be performed in place of the conventional ink peeling process accompanied by mechanical force such as high-density pulper or kneader. Specifically, there are the following two methods.
(1) When performing cavitation instead of the conventional ink peeling process with mechanical force. The deinking process in this case has the following configuration. : Cavitation treatment + (flotation and / or cleaning method)
(2) When ink is peeled off using a combination of conventional mechanical force and cavitation. The deinking process in this case has the following configuration. : (Mechanical force + Cavitation treatment) + (Flotation and / or cleaning method)

  As a device that peels ink by mechanical force, tab-type or drum-type pulpers, kneaders, mica processors, dispersers, etc. and Carre et al. (B. Carre, Y. Vernacand G. Galland, Pulp and Paper Canada, 99 ( 9), 46 (1998)), and equipment based on various disaggregation, kneading, and dispersion techniques. In particular, as described in (2) above, by combining the ink peeling device by mechanical force and the cavitation treatment, the ink peeling is performed by two different mechanisms, so that the operational effect is further increased. Further, if necessary, sodium hydroxide, sodium silicate, other alkaline chemicals, deinking agent, oxidizing bleaching agent, and reducing bleaching agent can be added. There is no restriction | limiting in particular about the ink peeling apparatus and ink removal apparatus to be used, or processing conditions. Further, if it is necessary to remove foreign matter or increase the whiteness, a foreign matter removing step or a bleaching step usually used in the deinking step can be incorporated.

  By applying cavitation treatment to the process of recycling existing waste paper, it is effective for peeling and miniaturizing dirt at relatively low concentrations and low temperatures, which is difficult with conventional deinking techniques. Therefore, by using the cavitation treatment, it is possible to produce a high-quality pulp without excessively dehydrating and increasing the concentration of the pulp.

  Further, in the cavitation treatment, when the ink is peeled from the pulp fiber, the ink can be peeled without using any deinking chemical. In conventional ink deinking methods such as kneaders used in the deinking process, the pulp fibers are rubbed together at a high concentration, so the ink is rubbed into the pulp fibers at the same time as the ink is peeled off. However, the method according to the present invention promotes the separation and dispersion of the ink at a low concentration, so that rubbing into the pulp fiber hardly occurs and the whiteness is high. Pulp is obtained. In this cavitation treatment, contaminants are removed, and at the same time, the beating action that causes less damage and shortening of the pulp fibers described later also occurs. Therefore, the obtained pulp has less impurities and high whiteness, and at the same time, bulkiness and tear strength. In addition, it has excellent properties in rigidity.

  In the present invention, the separated ink is effectively removed by appropriately combining the step of generating cavitation and the subsequent ink removal step consisting of flotation and / or washing. High quality DIP can be obtained. Furthermore, a better effect can be obtained by combining the present invention with a plurality of ink peeling steps, ink removing steps. As the flotation and cleaning apparatus, any apparatus for separating contaminants from known or novel fibers may be used.

  In the newspaper printing paper of the present invention, the blending ratio of DIP from which contaminants adhering to pulp fibers and ash are removed by cavitation treatment is not particularly limited. The ratio of DIP in conventional newspaper printing paper is 40 to 100% solids by weight, and it is preferably used within this range. DIP blend ratio that removes pollutants by bubbles generated by cavitation is the characteristic of paper quality that it is bulky but has little decrease in tear strength and rigidity, low contamination, high whiteness, and excellent ink setting. The higher the compounding rate, the more prominent it appears. From this point of view, it is desirable that the blending be as high as possible within the range of the blending ratio. Other raw pulps include chemical pulp (NBKP, NUKP, LBKP, LUKP, etc.), mechanical pulp (GP, RGP, TMP, CTMP, etc.), and non-wood fibers as appropriate according to the required quality of newspaper printing paper. Can be blended. The mechanical pulp may be hardwood or conifer.

  The newspaper printing paper of the present invention is an acidic paper that is made in an acidic region, a pseudo neutral paper that is made in a pseudo neutral region, a neutral paper that is made in a neutral region, Any of alkaline papers produced in the alkaline region of papermaking pH may be used. Further, neutral paper in which an alkaline chemical is applied to the surface of an acidic base paper made in an acidic region is also possible.

  The newspaper printing paper of the present invention may be blended with or without a filler, but a filler is preferably blended from the viewpoint of increasing opacity and post-printing opacity, and reducing back-through. When blending a filler, the filler generally used in acidic papermaking, neutral papermaking, or alkaline papermaking can be used, and is not particularly limited. For example, for pseudo neutral paper, neutral paper, alkaline paper, clay, calcined kaolin, deramikaolin, heavy calcium carbonate, light calcium carbonate, light calcium carbonate-silica composite, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide , Silicon oxide, amorphous silica (white carbon, etc.), aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide and other inorganic fillers, urea-formalin resin, polystyrene resin, phenol resin, micro hollow particles, etc. Organic fillers are used alone or in appropriate combination of two or more. Further, in acidic papermaking, a filler obtained by removing acid-soluble ones from the filler used in the neutral papermaking is used, and these are used alone or in combination of two or more as appropriate. Incidentally, amorphous silica and titanium dioxide have been frequently used in acidic papermaking, and these fillers can be used in the newsprint paper of the present invention.

  In the production of the newspaper printing paper of the present invention, various internal additive sizing agents may be blended. Various nonionic, cationic or amphoteric yield improvers, freeness improvers, paper strength improvers, and the like used in the past are appropriately selected and used as required. Is done.

  Further, for example, sulfuric acid bands, aluminum chloride, sodium aluminate, basic aluminum compounds such as basic aluminum chloride and basic polyaluminum hydroxide, water-soluble aluminum compounds such as water-degradable alumina sol, sulfuric acid A polyvalent metal compound such as ferrous sulfate or ferric sulfate, silica sol, or the like may be internally added.

  Other starches for papermaking, various starches, polyacrylamide, urea resin, melamine resin, epoxy resin, polyamide resin, polyamide, polyamine resin, polyamine, polyethyleneimine, vegetable gum, polyvinyl alcohol, latex, polyethylene oxide, hydrophilic cross-linked polymer Various compounds such as particle dispersions and derivatives or modified products thereof can be used.

  Furthermore, paper additives such as dyes, fluorescent brighteners, pH adjusters, antifoaming agents, pitch control agents, slime control agents and the like can be appropriately added depending on the intended use.

  The type of the paper machine is not particularly limited, and the paper machine can be made with a public paper machine such as a long net paper machine, a gap former, or a hybrid former (on-top former). The press line pressure is used within the normal operating range. The surface treatment agent may or may not be applied. When applying a surface treatment agent, there are no particular limitations on the components of the surface treatment agent, and there is no restriction on the type of size press, and the size of the liquid film transfer system such as a 2-roll size press, gate roll size press, or shim sizer. A press or the like can be used as appropriate. The calender is used at a linear pressure within the normal operating range. From the viewpoint of increasing the bulk of newspaper printing paper, a low linear pressure or a bypass is preferable as long as the smoothness of the paper can be maintained. A soft calendar is preferred.

  The surface treatment agent is not particularly limited. For example, raw starch, oxidized starch, esterified starch, cationized starch, enzyme-modified starch, aldehyde-modified starch, etherified starch (wet low molecular weight hydroxyethylated starch, dry low starch) Modified starch such as molecularized hydroxyethylated starch), cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, modified alcohols such as polyvinyl alcohol, carboxyl modified polyvinyl alcohol, styrene butadiene copolymer, polyvinyl acetate, vinyl chloride A vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, polyacrylic acid ester, polyacrylamide and the like can be used alone or in combination. Among them, the application of hydroxyethylated starch, which is excellent in the effect of improving the surface strength, is most preferable. In addition to the aforementioned agents, surface sizing agents such as styrene acrylic acid, styrene maleic acid, olefinic compounds, cationic sizing agents, and alkyl ketene dimer sizing agents can be applied to the surface treating agent.

  In the invention according to claim 1, in the step of recycling used paper, it contains DIP in which bubbles generated by cavitation are brought into contact with the used paper pulp suspension, and contaminants adhering to pulp fibers and ash are peeled off. Compared to newspaper printing paper containing DIP obtained by the conventional technology, regardless of whether it is acidic papermaking method, neutral papermaking method, or alkaline papermaking method, it has high whiteness. There is an effect that a high-quality newspaper printing paper excellent in ink depositing property can be obtained with little residual ink and high bulk while having little decrease in tear strength and rigidity.

  The invention according to claim 2 will be described below. In the newspaper printing paper according to the first aspect of the present invention, the filler added to the stock includes at least one selected from heavy calcium carbonate, light calcium carbonate, and light calcium carbonate-silica composite, In addition, the papermaking method is a neutral papermaking method.

  The filler content in the paper of these calcium carbonate-based fillers is 3 to 30 solids by weight, preferably 7.5 to 30 solids, and more preferably 10 to 30 solids. If the solid content is less than 3% by weight, the improvement in optical quality such as whiteness, opacity, and opacity after printing is small, and if it exceeds 30% by weight, it becomes difficult to make paper.

  Other fillers added to the stock include clay, calcined kaolin, deramikaolin, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide, silicon oxide, amorphous silica, aluminum hydroxide, calcium hydroxide, magnesium hydroxide Inorganic fillers such as zinc hydroxide and recycled fillers, urea-formalin resins, polystyrene resins, phenol resins, organic fillers such as fine hollow particles, and the like can be used as appropriate. The recycled filler refers to a filler obtained by dehydrating, firing, and pulverizing paper sludge made of flotator floss and / or other waste water generated from the deinked pulp manufacturing process.

  Since the invention according to claim 2 is a neutral newspaper printing paper, the internally added sizing agent added as necessary needs to exhibit a sizing degree in a neutral pH region, for example, an alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA), neutral rosin sizing agent, alkenyl ketene dimer and the like.

  As the surface sizing agent, it is preferable to use a surface sizing agent which is applied to a neutral newspaper printing paper base and has a large sizing degree, and a cationic surface sizing agent and an alkyl ketene dimer sizing agent are suitable.

  In the invention described in claim 2, newspaper printing paper is obtained in the same manner as in the invention described in claim 1 except for the filler, internal sizing agent, and surface sizing agent.

  The invention according to claim 2 has an effect that a high-quality newspaper printing paper having higher whiteness than that of the newspaper printing paper according to claim 1 can be obtained.

  The invention according to claim 3 will be described below. In the pulp manufacturing process, the present applicant has already filed a method for beating the pulp to prepare the pulp to a desired freeness by generating cavitation in the pulp suspension (Japanese Patent Application 2005). -33668). The present invention is a newspaper printing paper blended with pulp adjusted by this beating method. In the case of raw material pulp used for newspaper printing, the desired freeness may be in the range of the freeness of raw pulp obtained by a conventional beating method using mechanical force, and is not particularly limited. The specific freeness range for each type of raw material pulp cannot be generally stated because there are differences in the raw material tree type and pulp manufacturing method, but in general, it is 50 to 300 ml for DIP and softwood mechanical pulp. About 50 to 300 ml, about 50 to 300 ml for hardwood mechanical pulp, about 400 to 700 ml for softwood kraft pulp, and about 300 to 600 ml for hardwood kraft pulp. By generating air bubbles by cavitation and treating it by bringing it into contact with the pulp suspension, the degree of drainage can be adjusted without impairing the bulk of the pulp fiber by the collapse impact force of the generated fine air bubbles. The newspaper printing paper of the present invention made using paper is less bulky while being bulky than newspaper printing paper made using pulp with adjusted freeness by beating using mechanical force. There is little effect and it has the effect that it is excellent in ink inking property. Further, if the paper thickness is constant, the basis weight can be reduced, and the weight of newspaper printing paper can be reduced.

  When making paper, not just newspaper printing paper, the pulp freeness is adjusted by beating the pulp with mechanical force before paper making in order to obtain the target quality of paper such as paper strength and surface smoothness. . In the present invention, the target pulp with which bubbles generated by cavitation are brought into contact can be the target pulp as long as it is conventionally used as a raw material pulp for newsprint paper. Specifically, chemical pulp (NBKP, NUKP, LBKP, LUKP, etc.), mechanical pulp (GP, RGP, TMP, CTMP, etc.), and pulp such as DIP are targeted. The mechanical pulp may be coniferous or hardwood. Further, the DIP according to claim 1 described above, wherein the bubbles generated by cavitation are brought into contact with the waste paper pulp suspension to remove contaminants adhering to pulp fibers and ash. It can be set as the subject pulp of the invention.

  In the case of chemical pulp and mechanical pulp, the place where the pulp is beaten by bubbles generated by cavitation may be any place in the pulping process and the preparation process, but when the fibrous material is defibrated to become pulp. It is preferable to apply. In the case of DIP, the place where the DIP is beaten by bubbles generated by cavitation is during the preparation process after the deinking process.

  In addition, by combining conventional beating by mechanical force and beating by cavitation, beating is performed by two different mechanisms, so that the beating characteristics of pulp fibers can be controlled and more desirable paper quality can be obtained. In this case, the order of beating by mechanical force and beating by cavitation does not matter.

  The newspaper printing paper of the present invention contains these raw pulp containing pulp prepared to have a desired freeness by bringing bubbles generated by cavitation into contact with at least one of these raw pulp suspensions. Newspaper printing paper. It is also possible to process all types of pulp to make paper.

  The blending ratio of pulp prepared to a desired freeness by bubbles generated by cavitation with respect to the total pulp is not particularly limited, but the higher the blending ratio, the higher the bulk, the less the decrease in rigidity, and the ink inking property. Provides excellent newspaper printing paper. From that viewpoint, 5 to 100% by solid weight is preferable, and 10 to 100% by solid weight is more preferable.

  The newspaper printing paper of the present invention is an acidic paper that is made in an acidic region, a pseudo neutral paper that is made in a pseudo neutral region, a neutral paper that is made in a neutral region, Any of alkaline papers produced in the alkaline region of papermaking pH may be used. Further, neutral paper in which an alkaline chemical is applied to the surface of an acidic base paper made in an acidic region is also possible.

  The newspaper printing paper of the present invention may be blended with or without a filler, but a filler is preferably blended from the viewpoint of increasing opacity, opacity after printing, and reducing back-through. When blending a filler, the filler generally used in acidic papermaking, neutral papermaking, or alkaline papermaking can be used, and is not particularly limited. For example, for pseudo neutral paper, neutral paper, alkaline paper, clay, calcined kaolin, deramikaolin, heavy calcium carbonate, light calcium carbonate, light calcium carbonate-silica composite, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide Inorganic fillers such as silicon oxide, amorphous silica, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, and zinc hydroxide, and organic fillers such as urea-formalin resin, polystyrene resin, phenol resin, and fine hollow particles alone Or two or more types are used in combination as appropriate. Further, in acidic papermaking, a filler obtained by removing acid-soluble ones from the filler used in the neutral papermaking is used, and these are used alone or in combination of two or more as appropriate. Incidentally, amorphous silica and titanium dioxide have been frequently used in acidic papermaking, and these fillers can be used in the newsprint paper of the present invention.

  In the production of the newspaper printing paper of the present invention, various internal additive sizing agents may be blended. Various nonionic, cationic or amphoteric yield improvers, freeness improvers, paper strength improvers, and the like used in the past are appropriately selected and used as required. Is done.

  Further, for example, sulfuric acid bands, aluminum chloride, sodium aluminate, basic aluminum compounds such as basic aluminum chloride and basic polyaluminum hydroxide, water-soluble aluminum compounds such as water-degradable alumina sol, sulfuric acid A polyvalent metal compound such as ferrous sulfate or ferric sulfate, silica sol, or the like may be internally added.

  Other starches for papermaking, various starches, polyacrylamide, urea resin, melamine resin, epoxy resin, polyamide resin, polyamide, polyamine resin, polyamine, polyethyleneimine, vegetable gum, polyvinyl alcohol, latex, polyethylene oxide, hydrophilic cross-linked polymer Various compounds such as particle dispersions and derivatives or modified products thereof can be used.

  Furthermore, paper additives such as dyes, fluorescent brighteners, pH adjusters, antifoaming agents, pitch control agents, slime control agents and the like can be appropriately added depending on the intended use.

  The type of the paper machine is not particularly limited, and the paper machine can be made with a public paper machine such as a long net paper machine, a gap former, or a hybrid former (on-top former). The press line pressure is used within the normal operating range. The surface treatment agent may or may not be applied. When applying a surface treatment agent, there are no particular limitations on the components of the surface treatment agent, and there is no restriction on the type of size press, and the size of the liquid film transfer system such as a 2-roll size press, gate roll size press, or shim sizer. A press or the like can be used as appropriate. The calender is used at a linear pressure within the normal operating range. From the viewpoint of increasing the bulk of newspaper printing paper, a low linear pressure or a bypass is preferable as long as the smoothness of the paper can be maintained. A soft calendar is preferred.

  The surface treatment agent is not particularly limited. For example, raw starch, oxidized starch, esterified starch, cationized starch, enzyme-modified starch, aldehyde-modified starch, etherified starch (wet low molecular weight hydroxyethylated starch, dry low starch) Modified starch such as molecularized hydroxyethylated starch), cellulose derivatives such as carboxymethylcellulose, hydroxyethylcellulose, methylcellulose, modified alcohols such as polyvinyl alcohol, carboxyl modified polyvinyl alcohol, styrene butadiene copolymer, polyvinyl acetate, vinyl chloride A vinyl acetate copolymer, polyvinyl chloride, polyvinylidene chloride, polyacrylic acid ester, polyacrylamide and the like can be used alone or in combination. Among them, the application of hydroxyethylated starch, which is excellent in the effect of improving the surface strength, is most preferable. In addition to the aforementioned agents, surface sizing agents such as styrene acrylic acid, styrene maleic acid, olefinic compounds, cationic sizing agents, and alkyl ketene dimer sizing agents can be applied to the surface treating agent.

  The invention according to claim 4 will be described below. The newspaper printing paper according to the present invention is a newspaper printing paper containing only the pulp after deinking (DIP), which is beaten by bubbles generated by cavitation. The DIP is a DIP manufactured by a conventional DIP manufacturing method, which includes an ink peeling process with mechanical force and an ink removing process. The waste paper used for the deinked pulp is the same as the waste paper used in the invention of claim 1.

  Further, the DIP according to the first aspect of the present invention may be a DIP in which air bubbles generated by cavitation are brought into contact with the waste paper pulp suspension and the contaminants adhering to the pulp fibers and ash are peeled off.

  The mixing ratio of DIP beaten by bubbles generated by cavitation to the total pulp is not particularly limited. The ratio of DIP in conventional newspaper printing paper is 40 to 100% solids by weight, and it is preferably used within this range. The characteristics of the paper quality, which is bulky but has little decrease in stiffness, high smoothness, and excellent ink inking properties, change according to the blending ratio of DIP beaten by bubbles generated by cavitation, blending ratio The higher the value, the more prominent. From this point of view, it is desirable that the blending be as high as possible within the range of the blending ratio.

  The DIP according to claim 1 of the present invention is a target pulp to be beaten by bubbles generated by cavitation, and the effect of using this beaten pulp as a raw pulp is low in rigidity and low in smoothness. In addition to being excellent in ink depositability, there is also an effect that the whiteness is high with less impurities.

  Other raw pulps include chemical pulp (NBKP, NUKP, LBKP, LUKP, etc.), mechanical pulp (GP, RGP, TMP, CTMP, etc.), and non-wood fibers as appropriate according to the required quality of newspaper printing paper. Can be blended. The mechanical pulp may be hardwood or conifer.

  A newspaper printing paper is obtained in the same manner as in the invention of claim 3 except for the above-mentioned pulp raw material composition.

  The invention according to claim 5 will be described below. The newspaper printing paper of the present invention is a newspaper printing paper containing a kraft pulp limited to the type of pulp beaten by bubbles generated by cavitation. The kraft pulp may be softwood or hardwood, and the degree of bleaching is not limited. That is, any of unbleached kraft pulp, semi-bleached kraft pulp, and bleached kraft pulp may be used.

  The blending ratio of kraft pulp beaten by bubbles generated by cavitation to the total pulp is not particularly limited, but the blending ratio of kraft pulp in conventional newspaper printing paper is 2 to 20% solids by weight. It is preferable to use within the range.

  In the newsprint paper of the present invention, the characteristic of the paper quality that it is bulky but has little decrease in rigidity and excellent ink inking property changes according to the mixing ratio of kraft pulp beaten by bubbles generated by cavitation, The higher the blending ratio, the more prominent.

  As other raw material pulp, mechanical pulp (GP, RGP, TMP, CTMP, etc.), DIP, and non-wood fiber can be appropriately blended according to the required quality of newspaper printing paper. The mechanical pulp may be hardwood or conifer.

  A newspaper printing paper is obtained in the same manner as in the invention of claim 3 except for the above-mentioned pulp raw material composition.

  The invention according to claim 6 will be described below. The newsprint paper of the present invention is a newsprint paper containing a pulp that is limited to mechanical pulp, and the type of pulp beaten by bubbles generated by cavitation. The type of mechanical pulp is not limited, and GP, RGP, TMP, CTMP, etc. can be used. The mechanical pulp may be coniferous or hardwood.

  Since mechanical pulp is produced by mechanically grinding wood logs or wood chips, the produced pulp contains a lot of binding fibers called shives. For this reason, mechanical pulp is processed using a shape separation type dust remover such as a slit screen in a fine selection process, and after removing large-sized bundling fibers, it is sent to the papermaking process, and other raw pulp and filler, After being mixed with internal chemicals and the like, it is made by a paper machine to produce newsprint paper. However, since there is a limit to the selection, the small shape of the squib passes through the dust removing device and is mixed into the finished mechanical pulp. When newspaper printing paper is made from such a papermaking material blended with mechanical pulp, shives are incorporated into the paper layer of the newspaper printing paper, which causes paper breaks in the papermaking process, There is a problem. In addition, when printing newspaper printing paper, it may cause a paper break in the printing machine, and the shive part may be out of print and the print quality may be reduced. In addition, there is a problem that the appearance quality of newspaper is deteriorated due to the presence of a foreign matter called shive.

  By bringing the bubbles generated by cavitation into contact with the suspension of mechanical pulp, the already defibrated pulp can be prepared to the desired freeness, but at the same time it is contained in the mechanical pulp. The inventors have found that the shive is efficiently defibrated. Therefore, the newspaper printing paper according to the sixth aspect has an effect that the number of shives is small in addition to being less bulky and having less decrease in stiffness and excellent ink deposition.

  The blending ratio of mechanical pulp beaten by bubbles generated by cavitation to the total pulp is not particularly limited, but the blending ratio of mechanical pulp in conventional newspaper printing paper is 5 to 40% solids by weight. It is preferable to use within the range.

  In the newsprint paper of the present invention, the paper quality features that it is bulky but has little decrease in stiffness, excellent ink deposition, and a small number of shave are the blending ratio of mechanical pulp beaten by bubbles generated by cavitation. It changes depending on the condition, and becomes more noticeable as the blending ratio is higher.

  As other raw material pulp, chemical pulp (NBKP, NUKP, LBKP, LUKP, etc.), DIP, and non-wood fiber can be appropriately blended according to the required quality of newspaper printing paper.

  A newspaper printing paper is obtained in the same manner as in the invention of claim 3 except for the above-mentioned pulp raw material composition.

  The invention according to claim 7 will be described below. The present invention includes at least one filler selected from heavy calcium carbonate, light calcium carbonate, and light calcium carbonate-silica composite as a filler to be added to the stock in the newsprint paper according to claims 3 to 6. And the papermaking method is a neutral papermaking method.

  The filler content in the paper of these calcium carbonate-based fillers is 3 to 30 solids by weight, preferably 7.5 to 30 solids, and more preferably 10 to 30 solids. If the solid content is less than 3% by weight, the improvement in optical quality such as whiteness, opacity, and opacity after printing is small, and if it exceeds 30% by weight, it becomes difficult to make paper.

  Other fillers added to the stock include clay, calcined kaolin, deramikaolin, magnesium carbonate, barium carbonate, titanium dioxide, zinc oxide, silicon oxide, amorphous silica, aluminum hydroxide, calcium hydroxide, magnesium hydroxide Inorganic fillers such as zinc hydroxide and recycled fillers, urea-formalin resins, polystyrene resins, phenol resins, organic fillers such as fine hollow particles, and the like can be used as appropriate. The recycled filler refers to a filler obtained by dehydrating, firing, and pulverizing paper sludge made of flotator floss and / or other waste water generated from the deinked pulp manufacturing process.

  Since the invention according to claim 7 is a neutral newspaper printing paper, the internally added sizing agent to be added as necessary needs to express a sizing degree in a neutral pH region, for example, an alkyl ketene dimer (AKD), alkenyl succinic anhydride (ASA), neutral rosin sizing agent, alkenyl ketene dimer and the like.

  As the surface sizing agent, it is preferable to use a surface sizing agent which is applied to a neutral newspaper printing paper base and has a large sizing degree, and a cationic surface sizing agent and an alkyl ketene dimer sizing agent are suitable.

  In the invention of claim 7, newspaper printing paper is obtained in the same manner as in the invention of claims 3 to 6 except for the filler, the internal sizing agent and the surface sizing agent.

  The invention according to claim 7 has an effect that a high-quality newspaper printing paper having higher whiteness than that of the newspaper printing paper according to claims 3 to 6 can be obtained.

  The present invention will be described more specifically with reference to the following examples, but the present invention is not limited to such examples. In addition, all% in an example shows solid content weight%.

The adjustment method and pulp quality of DIP, kraft pulp (KP), and mechanical pulp (MP) used in Examples and Comparative Examples are shown below. Each test method and measurement method are as follows.
-Water retention: According to J.TAPPI No.26.
-Screening test: According to JIS P 8207: 1967.
-Canadian standard freeness (hereinafter referred to as CSF): in accordance with JIS P 8121: 1955.
-Thickness: According to JIS P 8118: 1998.
-Basis weight: According to JIS P 8124: 1988 (ISO536: 1995).
-Density and bulk: Calculated from the measured values of the thickness and basis weight of the handsheet.
-Breaking length and elongation: in accordance with JIS P 8113: 1998.
-Tear strength and specific tear strength: in accordance with JIS P 8116: 2000.
-Specific burst strength: in accordance with JIS P 8112: 1994.
Whiteness: Measured with a color difference meter (Murakami Color Co., Ltd.) according to JIS P 8148.
-Opacity: According to JIS P 8149: 2000.
Specific scattering coefficient, specific absorption coefficient: Measured with a color difference meter (Murakami Color Co., Ltd.) according to TAPPI T425om-91.
<Adjustment of cavitation treated pulp>
In FIG. 1, a pulp suspension (concentration 1.1%) (not shown) is accommodated in a sample tank 1, and a temperature sensor 12 and a mixer 13 are inserted into the sample tank 1. The pulp suspension in the sample tank 1 is introduced as a jet liquid into the cavitation jet cell 3 through a predetermined pipe via the plunger pump 4. A nozzle 2 is provided below the cavitation jet cell 3, and more specifically, a pulp suspension in the sample tank 1 is jetted from the nozzle 2 into the jet cell 3. Further, a water supply valve 9 and a circulation valve 10 are provided in a pipe from the side of the sample tank 1 toward the jet cell 3, and the pulp suspension in the sample tank 1 is supplied into the jet cell 3 as an injection liquid. An upstream pressure control valve 5 is interposed in another pipe from the side of the sample tank 1 toward the nozzle 2. On the other hand, a downstream pressure control valve 6 is interposed in another pipe from the upper part of the jet cell 3 to the sample tank 1, and the pulp suspension is injected into the nozzle 2 by adjusting the valves 5 and 6. The pressure can be adjusted. An upstream pressure gauge 7 is provided on the inlet side of the nozzle 2, and a downstream pressure gauge 8 is provided on the upper part of the jet cell 3. A drain valve 11 is provided at the bottom of the jet cell 3.

[DIP1 for Example]
As a sample for deinking, old newspapers that had passed over a year and a half after printing were shredded into 2cm x 2cm. Sodium hydroxide 1.0% by weight was added to 660 g of waste paper absolutely dried, and the pulp concentration was adjusted to 15% by weight with water, and then pulped for 6 minutes at 40 ° C. to obtain a disaggregation raw material A. Water was added to the disaggregated sample to dilute the waste paper concentration to 1.1% by weight, and 1.1% by weight of the pulp suspension was sprayed on the diluted pulp suspension using a cavitation jet cleaning device. In the cavitation jet cleaning apparatus, the pressure (downstream pressure) of the container to be ejected was 0.1 Mpa, the pressure of the spray liquid (upstream pressure) was 3 Mpa, and the treatment was performed for 5 minutes. The obtained fraction was measured for CSF, and the treated pulp was thoroughly washed on a 150 mesh wire. Based on JIS P 8222: 1998, five 60 g / m ² hand-sheets were prepared for the washed pulp. The whiteness and hue of handsheets were measured. Furthermore, in order to measure the residual ink, the fine ink was measured as an ERIC (effective residual ink density) value using a residual ink measuring device (Color Touch: manufactured by Technidyne). For coarse inks, a dirt measuring device (Spec Scan 2000: manufactured by Apology Technology) was used to measure 0.05 mm ² or more of dirt on five different hand-made sheets by image processing, and the average value The unpeeled ink area was measured. The pulp quality is shown in Table 1.

[DIP2 for Example]
In the cavitation jet cleaning apparatus, the pressure (downstream pressure) of the container to be ejected was set to 0.1 MPa, the pressure of the spray liquid (upstream pressure) was set to 5 MPa, and the treatment was performed for 5 minutes. Except this, it was carried out in the same manner as the preparation of DIP1 for Examples. The pulp quality is shown in Table 1.

[DIP3 for Example]
In a cavitation jet cleaning apparatus, the pressure (downstream pressure) of the container to be ejected was 0.1 Mpa, the pressure of the spray liquid (upstream pressure) was 7 Mpa, and the treatment was performed for 5 minutes. Except this, it was carried out in the same manner as the preparation of DIP1 for Examples. The pulp quality is shown in Table 1.

[DIP4 for Example]
In a cavitation jet cleaning apparatus, the pressure (downstream pressure) of the container to be ejected was 0.1 Mpa, the pressure of the spray liquid (upstream pressure) was 9 Mpa, and the treatment was performed for 5 minutes. Except this, it was carried out in the same manner as the preparation of DIP1 for Examples. The pulp quality is shown in Table 1.

[DIP1 for comparative example]
The disaggregation raw material A was sufficiently washed with a 150 mesh wire. About the pulp after washing | cleaning, the handsheet was created by operation similar to DIP for an Example. The same items as the DIP for Example were measured for the handsheets. The pulp quality is shown in Table 1.

[DIP2 for comparative example]
The disaggregation raw material A was diluted with water and beaten 3,000 counts with a clearance of 0.2 mm using a PFI mill. The obtained beaten pulp was thoroughly washed with 150 mesh wire. About the pulp after washing | cleaning, the handsheet was created by operation similar to DIP for an Example. The same items as the DIP for Example were measured for the handsheets. The pulp quality is shown in Table 1.

[DIP3 for comparative example]
Beating 5,000 counts with a clearance of 0.2mm using a PFI mill. Except this, the same procedure as in Comparative Example DIP2 was performed. The pulp quality is shown in Table 1.

[DIP4 for comparative example]
Beating 7,000 counts with a clearance of 0.2mm using a PFI mill. Except this, the same procedure as in Comparative Example DIP2 was performed. The pulp quality is shown in Table 1.

[DIP5 for Example]
Newspaper-based DIP manufactured in the factory (DIP whose used paper is newspaper used paper) was used as the raw material B-1. After adjusting the concentration of the raw material B-1 to 1.1% by weight, using a cavitation jet cleaning device (nozzle diameter 1.5 mm), the pressure of the jet liquid (upstream pressure) is 7 Mpa (jet flow rate 70 m / sec) The inner pressure (downstream pressure) was set to 0.3 Mpa, and the treatment was performed for 2 minutes. In addition, a pulp suspension having a concentration of 1.1% by weight was used as a propellant, and the pulp suspension in the container was subjected to cavitation treatment. After treatment, CSF and curl were measured. Based on the Tappi standard method, 5 hand-sheets of 60 g / m ² were prepared using the treated pulp. The density, tear length, specific burst strength, Oken smoothness, and air resistance of the handsheet were measured. For the remaining ink of 100 μm or more (visible) and 250 μm or more of coarse ink, use a contaminant measurement device (Spec Scan 2000: manufactured by Apology Technology Co., Ltd.) to perform image processing on the darts on five different hand-sheets. The unpeeled ink area per unit area was measured from the average value. The pulp quality is shown in Table 3.

[DIP6 for Example]
The procedure was the same as Example DIP5 except that the treatment time with a cavitation jet cleaning device (nozzle diameter 1.5 mm) was set to 6 minutes. The pulp quality is shown in Table 3.

[DIP7 for Example]
The same procedure as in DIP5 for Example was performed except that the treatment time with a cavitation jet cleaning device (nozzle diameter 1.5 mm) was 12 minutes. The pulp quality is shown in Table 3.

[DIP8 for Example]
High-quality DIP (DIP whose raw paper is high-quality waste paper) manufactured at the factory was used as the raw material B-2. After adjusting the concentration of the raw material B-2 to 1.1% by weight, using a cavitation jet cleaning device (nozzle diameter 1.5mm), the pressure of the jet liquid (upstream pressure) is 7Mpa (jet flow rate 70m / sec) The inner pressure (downstream pressure) was set to 0.3 Mpa, and the treatment was performed for 2 minutes. In addition, a pulp suspension having a concentration of 1.1% by weight was used as a propellant, and the pulp suspension in the container was subjected to cavitation treatment. After treatment, CSF and curl were measured. Using the treated pulp, 5 hand-sheets of 60 g / m ² were prepared based on JIS P 8222: 1998. The density, tear length, specific burst strength, Oken smoothness, and air resistance of the handsheet were measured. For the remaining ink of 100 μm or more (visible) and 250 μm or more of coarse ink, use a contaminant measurement device (Spec Scan 2000: manufactured by Apology Technology Co., Ltd.) to perform image processing on the darts on five different hand-sheets. The unpeeled ink area per unit area was measured from the average value. The pulp quality is shown in Table 3.

[DIP9 for Example]
The same procedure as in Example DIP8 was carried out except that the treatment time with a cavitation jet cleaning device (nozzle diameter 1.5 mm) was set to 6 minutes. The pulp quality is shown in Table 3.

[DIP10 for Example]
Except that the treatment time with a cavitation jet cleaning device (nozzle diameter 1.5 mm) was 12 minutes, the same procedure as in DIP8 for Example was performed. The pulp quality is shown in Table 3.

[DIP5 for comparative example]
A handsheet was prepared in the same manner as the DIP 5 for Example from the raw material B-1 which was not treated with the cavitation jet cleaning device, and the same items were measured. The pulp quality is shown in Table 3.

[DIP6 for comparative example]
The raw material B-1 was beaten to 1,000 counts using a PFI mill at a concentration of 10% and a clearance of 0.2 mm. The same items as above were measured for the pulp after beating. The pulp quality is shown in Table 3.

[DIP7 for comparative example]
The raw material B-1 was beaten up to 3,000 counts using a PFI mill at a concentration of 10% and a clearance of 0.2 mm. The same items as above were measured for the pulp after beating. The pulp quality is shown in Table 3.

[DIP8 for comparative example]
The raw material B-1 was beaten to 5,000 counts using a PFI mill at a concentration of 10% and a clearance of 0.2 mm. The same items as above were measured for the pulp after beating. The pulp quality is shown in Table 3.

[DIP9 for comparative example]
A handsheet was prepared in the same manner as in Example DIP8 from the raw material B-2 that was not treated with the cavitation jet cleaning apparatus, and the same items were measured. The pulp quality is shown in Table 3.

[DIP10 for comparative example]
The raw material B-2 was beaten up to 1,000 counts using a PFI mill at a concentration of 10% and a clearance of 0.2 mm. The same items as above were measured for the pulp after beating. The pulp quality is shown in Table 3.

[DIP11 for comparative example]
The raw material B-2 was beaten up to 3,000 counts using a PFI mill at a concentration of 10% and a clearance of 0.2 mm. The same items as above were measured for the pulp after beating. The pulp quality is shown in Table 3.

[DIP12 for comparative example]
The raw material B-2 was beaten up to 5,000 counts using a PFI mill at a concentration of 10% and a clearance of 0.2 mm. The same items as above were measured for the pulp after beating. The pulp quality is shown in Table 3.

[Example KP1]
Commercial LBKP was disaggregated with a low-concentration pulper to obtain raw material C (CSF = 666 ml). After adjusting the concentration of raw material C to 1.1% by weight, using a cavitation jet cleaning device (nozzle diameter 1.5mm), the pressure of the jet liquid (upstream pressure) was 7Mpa (jet flow rate 70m / sec), The pressure (downstream pressure) was set at 0.3 Mpa for 2 minutes. In addition, a pulp suspension having a concentration of 1.1% by weight was used as a propellant, and the pulp suspension in the container was subjected to cavitation treatment. The pulp quality is shown in Table 3.

  Furthermore, five hand-sheets were produced from the treated pulp according to JIS P 8222: 1998. The thickness and basis weight of the handsheet were measured, and the density and bulk were calculated based on this. Further, the fracture length, specific tear strength, specific burst strength, whiteness, opacity, specific scattering coefficient, and absorption coefficient were measured and calculated. The results are shown in Table 4.

[Example KP2]
The same procedure as in Example KP1 was carried out except that the treatment time with a cavitation jet cleaning device (nozzle diameter: 1.5 mm) was 5 minutes. The results are shown in Tables 3 and 4.

[Example KP3]
The same procedure as in Example KP1 was carried out except that the treatment time with a cavitation jet cleaning device (nozzle diameter 1.5 mm) was 10 minutes. The results are shown in Tables 3 and 4.

[Example KP4]
The same procedure as in Example KP1 was carried out except that the treatment time with a cavitation jet cleaning device (nozzle diameter 1.5 mm) was 15 minutes. The results are shown in Tables 3 and 4.

[KP1 for comparative example]
The water retention, sieving test and Canadian standard freeness (CSF) of raw material C were measured. The results are shown in Table 3. Further, for the hand-sheet of the raw material C, the same items as those of the example KP1 were measured. The results are shown in Table 4.

[KP2 for comparative example]
The raw material C was beaten up to 3,000 counts using a PFI mill at a concentration of 10% and a clearance of 0.2 mm. The same items as above were measured for the pulp after beating. The results are shown in Tables 3 and 4.

[KP3 for comparative example]
The test was performed in the same manner as KP2 for Comparative Example except that the beating time by the PFI mill was set to 5,000 counts. The results are shown in Tables 3 and 4.

[KP4 for comparative example]
The test was performed in the same manner as KP2 for the comparative example except that the beating time by the PFI mill was set to 7,000 counts. The results are shown in Tables 3 and 4.

[KP5 for comparative example]
The test was performed in the same manner as KP2 for Comparative Example except that the beating time by the PFI mill was set to 10,000 counts. The results are shown in Tables 3 and 4.

[MP1 for Example]
Radiatapine TMP (CSF = 288 ml) after secondary refining of the actual plant was used as raw material D. After adjusting the concentration of raw material D to 1.1% by weight, using a cavitation jet cleaning device (nozzle diameter 1.5mm), the pressure of the jet liquid (upstream pressure) was 7MPa (jet flow rate 70m / sec), The pressure (downstream pressure) was set to 0.3 MPa and the treatment was performed for 2 minutes. In addition, a pulp suspension having a concentration of 1.1% by weight was used as a propellant, and the pulp suspension in the container was subjected to cavitation treatment. The treated pulp was measured for water retention, sieving test, and CSF. For the treated pulp, five hand-sheets were prepared based on JIS P 8222: 1998. The thickness, basis weight, density, bulk, tear length, specific tear strength, specific burst strength, whiteness, opacity, specific scattering coefficient, and absorption coefficient of the handsheet were measured and calculated. The results are shown in Tables 5 and 6.

[MP2 for Example]
The same procedure as in Example MP1 was carried out except that the treatment time with a cavitation jet cleaning device (nozzle diameter: 1.5 mm) was 5 minutes. The results are shown in Tables 5 and 6.

[MP3 for example]
The same procedure as in Example MP1 was carried out except that the treatment time with a cavitation jet cleaning device (nozzle diameter 1.5 mm) was 10 minutes. The results are shown in Tables 5 and 6.

[MP4 for Example]
The same procedure as in Example MP1 was carried out except that the treatment time with a cavitation jet cleaning device (nozzle diameter 1.5 mm) was 15 minutes. The results are shown in Tables 5 and 6.

[MP1 for comparative example]
The raw material D was measured for water retention, sieving test and Canadian standard freeness (CSF). The results are shown in Table 5. In addition, thickness, basis weight, density, bulk, tear length, specific tear strength, specific burst strength, whiteness, opacity, specific scattering coefficient, and absorption coefficient are measured for hand-made sheet of raw material D. Calculated. The results are shown in Tables 5 and 6.

[MP2 for comparative example]
Raw material D was beaten up to 1,000 counts using a PFI mill at a concentration of 10% and a clearance of 0.2 mm. The same items as above were measured for the pulp after beating. The results are shown in Tables 5 and 6.

[MP3 for comparative example]
Raw material D was beaten up to 2,000 counts using a PFI mill at a concentration of 10% and a clearance of 0.2 mm. The same items as above were measured for the pulp after beating. The results are shown in Tables 5 and 6.

[MP4 for comparative example]
Raw material D was beaten up to 3,000 counts using a PFI mill at a concentration of 10% and a clearance of 0.2 mm. The same items as above were measured for the pulp after beating. The results are shown in Tables 5 and 6.

[MP5 for comparative example]
Raw material D was beaten up to 5,000 counts using a PFI mill at a concentration of 10% and a clearance of 0.2 mm. The same items as above were measured for the pulp after beating. The results are shown in Tables 5 and 6.

The method for measuring the quality of newspaper printing paper manufactured in the following examples and comparative examples is as follows.
・ Initial pure bending stiffness: After adjusting the humidity at 23 ° C and 50% RH, the MD of the test piece cut into MD100mm and CD100mm was tested with a pure bending stiffness tester (trade name: JTC-1, manufactured by Nippon Seiki Seisakusho Co., Ltd.) Then, bending was performed at a deformation rate of 0.2 cm ^-1 / sec, the curvature and torque were measured, and the initial pure bending stiffness was calculated from the gradient of the obtained bending moment-curvature curve.
-Beck smoothness: measured according to JIS P 8119.
-Ink fillability: The produced newspaper printing paper was printed with an offset printing machine, and the ink printing unevenness of the printed newspaper was evaluated. Evaluation was made into four grades of ◎ (excellent), ○ (good), △ (normal), and × (defective).

[Example 1]
Example DIP1 / Radiatapine TMP (CSF = 100 ml, whiteness 45.0%, opacity 95.0%) / NKP (CSF = 200 ml, whiteness 83.0%, opacity 65.0%) = 75/18/7 (solid content (Weight ratio) mixed pulp slurry, 1.5% sulfuric acid band to pulp and 2% white carbon to pulp were added, using a twin wire type test paper machine, jet / wire ratio 101%, paper making speed 1,200 m / min The base paper was made with Hydroxyethylated starch (ETHYLEX2025, manufactured by Staley) / surface sizing agent (KN-520, manufactured by Harima Chemicals Co., Ltd.) = 5/1 (solid content weight ratio) surface treatment agent on both sides of the base paper 1.2 g / m ² ( After applying to solid weight and drying, acid newsprint paper with basis weight of 43g / m ² was manufactured by high temperature soft nip calendering at 120 ° C and linear pressure of 20kgf / cm. It was shown to.

[Example 2]
Acid newsprint paper was produced in the same manner as in Example 1 except that Example DIP2 was used instead of Example DIP1. The paper quality results are shown in Table 7.

[Example 3]
Acid newsprint paper was produced in the same manner as in Example 1 except that Example DIP3 was used instead of Example DIP1. The paper quality results are shown in Table 7.

[Example 4]
An acid newsprint paper was produced in the same manner as in Example 1 except that Example Deinking DIP4 was used instead of Example DIP1. The paper quality results are shown in Table 7.

[Comparative Example 1]
Acid newsprint paper was produced in the same manner as in Example 1, except that DIP 1 for Comparative Example was used instead of DIP 1 for Example. The paper quality results are shown in Table 7.

[Comparative Example 2]
Acid newsprint paper was produced in the same manner as in Example 1 except that DIP 2 for Comparative Example was used instead of DIP 1 for Example. The paper quality results are shown in Table 7.

[Comparative Example 3]
Acid newsprint paper was produced in the same manner as in Example 1 except that DIP 3 for Comparative Example was used instead of DIP 1 for Example. The paper quality results are shown in Table 7.

[Comparative Example 4]
Acid newsprint paper was produced in the same manner as in Example 1 except that DIP 4 for Comparative Example was used instead of DIP 1 for Example. The paper quality results are shown in Table 7.

[Example 5]
Example DIP1 / Radiatapine TMP (CSF = 100 ml, whiteness 45.0%, opacity 95.0%) / NKP (CSF = 200 ml, whiteness 83.0%, opacity 65.0%) = 75/18/7 (solid content (Weight ratio) mixed pulp slurry was added 10% light calcium carbonate to pulp, and paper was made using a twin wire type test paper machine at a jet / wire ratio of 101% and a paper making speed of 1,200 m / min. Hydroxyethylated starch (ETHYLEX2025, manufactured by Staley) / surface sizing agent (LC123L, manufactured by Harima Chemicals Co., Ltd.) = 5/1 (solid weight ratio) surface treatment agent 1.2 g / m ² (solid content on both sides of the base paper) After applying to the weight and drying, neutral newspaper printing paper with a basis weight of 43g / m ² was manufactured by high-temperature soft nip calendering at 120 ° C and linear pressure of 20kgf / cm. Indicated.

[Example 6]
Neutral newsprint paper was produced in the same manner as in Example 5 except that Example DIP2 was used instead of Example DIP1. The paper quality results are shown in Table 7.

[Example 7]
Neutral newsprint paper was produced in the same manner as in Example 5 except that Example DIP3 was used instead of Example DIP1. The paper quality results are shown in Table 7.

[Example 8]
Neutral newsprint paper was produced in the same manner as in Example 5 except that Example DIP4 was used instead of Example DIP1. The paper quality results are shown in Table 7.

[Comparative Example 5]
Neutral newsprint paper was produced in the same manner as in Example 5 except that DIP 1 for Comparative Example was used instead of DIP 1 for Example. The paper quality results are shown in Table 7.

[Comparative Example 6]
A neutral newsprint paper was produced in the same manner as in Example 5 except that DIP 2 for Comparative Example was used instead of DIP 1 for Example. The paper quality results are shown in Table 7.

[Comparative Example 7]
Neutral newsprint paper was produced in the same manner as in Example 5 except that DIP 3 for Comparative Example was used instead of DIP 1 for Example. The paper quality results are shown in Table 7.

[Comparative Example 8]
Neutral newsprint paper was produced in the same manner as in Example 5, except that DIP 4 for Comparative Example was used instead of DIP 1 for Example. The paper quality results are shown in Table 7.

In acid newspaper printing paper, Examples 1 to 4 containing DIP from which pollutants were peeled off by bubbles generated by cavitation were used in Comparative Example 1 containing DIP that was disaggregated and washed, and to remove pollutants by mechanical force. Compared with the washed Comparative Examples 2 to 4, the following can be understood.
(1) The fine ink displayed by ERIC value is greatly reduced and the whiteness tends to be high.
(2) Low density and high bulk, high tear strength, high initial pure bending stiffness and excellent rigidity.
(3) The smoothness is high and the ink inking property is excellent.
These tendencies are clearer when comparing Example 3 and Comparative Example 2 in which DIP containing almost the same CSF is blended.
Even in neutral newspaper printing paper, Examples 5 to 8 clearly show the above (1), (2), and (3) as compared with Comparative Examples 5 to 8. In addition, it turns out that Examples 5-8 which are neutral newspaper printing paper have whiteness higher than Examples 1-4 which are acidic newspaper printing paper.

[Example 9]
Example DIP5 / TMP (CSF = 100 ml, whiteness 45.0%, opacity 95.0%) / NKP (CSF = 200 ml, whiteness 83.0%, opacity 65.0%) = 75/18/7 (solid content weight ratio) Add 1.5% sulfuric acid band to pulp and 2% white carbon to pulp to the mixed pulp slurry, and use a twin wire type test paper machine to create a base paper at a jet / wire ratio of 101% and a papermaking speed of 1,200 m / min. Made paper. Hydroxyethylated starch (ETHYLEX2025, manufactured by Staley) / surface sizing agent (KN-520, manufactured by Harima Chemicals Co., Ltd.) = 5/1 (solid content weight ratio) surface treatment agent on both sides of the base paper 1.2 g / m ² ( After applying to solid weight and drying, acid newsprint paper with basis weight of 43g / m ² was manufactured by high-temperature soft nip calendering at 120 ° C and linear pressure of 20kgf / cm. It was shown to.

[Example 10]
Acid newsprint paper was produced in the same manner as in Example 9, except that Example DIP6 was used instead of Example DIP5. The paper quality results are shown in Table 8.

[Example 11]
An acid newsprint paper was produced in the same manner as in Example 9, except that Example Deinking DIP7 was used instead of Example DIP5. The paper quality results are shown in Table 8.

[Example 12]
Acid newsprint paper was produced in the same manner as in Example 9, except that Example DIP8 was used instead of Example DIP5. The paper quality results are shown in Table 8.

[Example 13]
Acid newsprint paper was produced in the same manner as in Example 9, except that Example DIP9 was used instead of Example DIP5. The paper quality results are shown in Table 8.

[Example 14]
Acid newsprint paper was produced in the same manner as in Example 9, except that Example DIP10 was used instead of Example DIP5. The paper quality results are shown in Table 8.

[Comparative Example 9]
Acid newsprint paper was produced in the same manner as in Example 9, except that DIP 5 for Comparative Example was used instead of DIP 5 for Example. The paper quality results are shown in Table 8.

[Comparative Example 10]
Acid newsprint paper was produced in the same manner as in Example 9, except that Comparative Example DIP6 was used instead of Example DIP5. The paper quality results are shown in Table 8.

[Comparative Example 11]
Acid newsprint paper was produced in the same manner as in Example 9 except that DIP 7 for Comparative Example was used instead of DIP 5 for Example. The paper quality results are shown in Table 8.

[Comparative Example 12]
Acid newsprint paper was produced in the same manner as in Example 9 except that DIP 8 for Comparative Example was used instead of DIP 5 for Example. The paper quality results are shown in Table 8.

[Comparative Example 13]
Acid newsprint paper was produced in the same manner as in Example 9 except that DIP 9 for Comparative Example was used instead of DIP 5 for Example. The paper quality results are shown in Table 8.

[Comparative Example 14]
Acid newsprint paper was produced in the same manner as in Example 9 except that DIP 10 for Comparative Example was used instead of DIP 5 for Example. The paper quality results are shown in Table 8.

[Comparative Example 15]
Acid newsprint paper was produced in the same manner as in Example 9 except that DIP11 for Comparative Example was used instead of DIP5 for Example. The paper quality results are shown in Table 8.

[Comparative Example 16]
Acid newsprint paper was produced in the same manner as in Example 9 except that DIP 12 for Comparative Example was used instead of DIP 5 for Example. The paper quality results are shown in Table 8.

[Example 15]
Example DIP5 / Radiatapine TMP (CSF 100ml, whiteness 45.0%, opacity 95.0%) / NKP (CSF200ml, whiteness 83.0%, opacity 65.0%) = 75/18/7 (solid content weight ratio) To the mixed pulp slurry, 10% of light calcium carbonate was added to the pulp, and the base paper was made using a twin wire type test paper machine at a jet / wire ratio of 101% and a paper making speed of 1,200 m / min. Hydroxyethylated starch (ETHYLEX2025, manufactured by Staley) / surface sizing agent (LC123L, manufactured by Harima Chemicals Co., Ltd.) = 5/1 (solid weight ratio) surface treatment agent 1.2 g / m ² (solid content on both sides of the base paper) After applying to weight and drying, neutral newspaper printing paper with a basis weight of 43g / m ² was manufactured by high-temperature soft nip calendering at 120 ° C and linear pressure of 20kgf / cm. Indicated.

[Example 16]
Neutral newsprint paper was produced in the same manner as in Example 15 except that Example DIP6 was used instead of Example DIP5. The paper quality results are shown in Table 8.

[Example 17]
Neutral newsprint paper was produced in the same manner as in Example 15 except that Example DIP7 was used instead of Example DIP5. The paper quality results are shown in Table 8.

[Example 18]
Neutral newsprint paper was produced in the same manner as in Example 15 except that Example DIP8 was used instead of Example DIP5. The paper quality results are shown in Table 8.

[Example 19]
Neutral newsprint paper was produced in the same manner as in Example 15 except that Example DIP9 was used instead of Example DIP5. The paper quality results are shown in Table 8.

[Example 20]
Neutral newsprint paper was produced in the same manner as in Example 15 except that Example DIP10 was used instead of Example DIP5. The paper quality results are shown in Table 8.

[Comparative Example 17]
Neutral newsprint paper was produced in the same manner as in Example 15 except that Comparative Example DIP5 was used instead of Example DIP5. The paper quality results are shown in Table 8.

[Comparative Example 18]
Neutral newsprint paper was produced in the same manner as in Example 15 except that DIP 6 for comparative example was used instead of DIP 5 for example. The paper quality results are shown in Table 8.

[Comparative Example 19]
Neutral newsprint paper was produced in the same manner as in Example 15 except that DIP 7 for Comparative Example was used instead of DIP 5 for Example. The paper quality results are shown in Table 8.

[Comparative Example 20]
Neutral newsprint paper was produced in the same manner as in Example 15 except that DIP 8 for Comparative Example was used instead of DIP 5 for Example. The paper quality results are shown in Table 8.

[Comparative Example 21]
Neutral newsprint paper was produced in the same manner as in Example 15 except that Comparative Example DIP9 was used instead of Example DIP5. The paper quality results are shown in Table 8.

[Comparative Example 22]
Neutral newsprint paper was produced in the same manner as in Example 15 except that DIP 10 for comparative example was used instead of DIP 5 for example. The paper quality results are shown in Table 8.

[Comparative Example 23]
Neutral newsprint paper was produced in the same manner as in Example 15 except that DIP11 for comparative example was used instead of DIP5 for Example. The paper quality results are shown in Table 8.

[Comparative Example 24]
Neutral newsprint paper was produced in the same manner as Example 15 except that DIP 12 for Comparative Example was used instead of DIP 5 for Example. The paper quality results are shown in Table 8.

In acid newspaper printing paper (Examples 9 to 11 and Comparative Examples 9 to 12) using newspaper-based waste paper as a raw material for DIP, Example 9 containing DIP prepared to a desired freeness by bubbles generated by cavitation ˜11 shows the following compared to Comparative Example 9 containing unbeaten DIP and Comparative Examples 10 to 12 containing DIP beaten by mechanical force.
(1) Low density and bulky, high initial pure bending stiffness and excellent rigidity.
(2) High smoothness and excellent ink fillability.
These tendencies are clear from the comparison between Example 9 and Comparative Example 10, the comparison between Example 10 and Comparative Example 11, and the comparison between Example 11 and Comparative Example 12, in which CSF is blended with DIP that is almost identical. It is.
In acid newspaper printing paper (Examples 12 to 14, Comparative Examples 13 to 16) made from high-quality waste paper, Examples 12 to 14 containing DIP adjusted to a desired freeness by bubbles generated by cavitation Compared to Comparative Example 13 containing unbeaten DIP and Comparative Examples 14 to 16 containing DIP beaten by mechanical force, the above (1) and (2) can be said similarly. These tendencies are clear from the comparison between Example 12 and Comparative Example 14 in which DIP having almost the same CSF was blended.
Even in neutral newspaper printing paper (Examples 15 to 17 and Comparative Examples 17 to 20) using newspaper-based waste paper as a raw material for DIP, Examples 15 to 17 are similar to the above (1) in comparison with Comparative Examples 17 to 20. ) And (2) are clear. In addition, it turns out that Examples 15-17 which are neutral newspaper printing paper have whiteness higher than Examples 9-11 which are acidic newspaper printing paper.
Even in neutral newspaper printing paper (Examples 18 to 20, Comparative Examples 21 to 24) using high-quality waste paper as a DIP raw material, Examples 18 to 20 are similar to the above (1 ) And (2) are clear. In addition, it turns out that Examples 18-20 which are neutral newspaper printing paper have whiteness higher than Examples 12-14 which are acidic newspaper printing paper.

[Example 21]
Wastepaper DIP (CSF = 90ml, whiteness 60.2%, opacity 83.0%) / Radiatapine TMP (CSF = 100ml, whiteness 45.0%, opacity 95.0%) / Example KP1 = 75/10/15 To the mixed pulp slurry of (solid weight ratio), sulfuric acid band 1.5% to pulp and white carbon 2% to pulp were added, using a twin wire type test paper machine, jet / wire ratio 101%, paper making speed 1,200 Paper was made at m / min. Hydroxyethylated starch (ETHYLEX2025, manufactured by Staley) / surface sizing agent (KN-520, manufactured by Harima Chemicals Co., Ltd.) = 5/1 (solid content weight ratio) surface treatment agent on both sides of the base paper 1.2 g / m ² ( After applying to solid weight and drying, acidic newsprint paper with a basis weight of 43g / m ² was manufactured by high-temperature soft nip calendering at 120 ° C and linear pressure of 20kgf / cm. It was shown to.

[Example 22]
Acid newsprint paper was produced in the same manner as in Example 21 except that Example KP2 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Example 23]
Acid newsprint paper was produced in the same manner as in Example 21, except that Example KP3 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Example 24]
Acid newsprint paper was produced in the same manner as in Example 21, except that Example KP4 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Comparative Example 25]
Acid newsprint paper was produced in the same manner as in Example 21 except that Comparative Example KP1 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Comparative Example 26]
Acid newsprint paper was produced in the same manner as in Example 21 except that Comparative Example KP2 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Comparative Example 27]
Acid newsprint paper was produced in the same manner as in Example 21, except that Comparative Example KP3 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Comparative Example 28]
Acid newsprint paper was produced in the same manner as in Example 21, except that KP4 for Comparative Example was used instead of KP1 for Example. The paper quality results are shown in Table 9.

[Comparative Example 29]
Acid newsprint paper was produced in the same manner as in Example 21, except that Comparative Example KP5 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Example 25]
Wastepaper DIP (CSF 90ml, whiteness 60.2%, opacity 83.0%) / Radiatapine TMP (CSF 100ml, whiteness 45.0%, opacity 95.0%) / Example KP1 = 75/10/15 (solid weight) Ratio) was added to 10% light calcium carbonate, and paper was made using a twin wire type test paper machine at a jet / wire ratio of 101% and a paper making speed of 1,200 m / min. Hydroxyethylated starch (ETHYLEX2025, manufactured by Staley) / surface sizing agent (LC123L, manufactured by Harima Chemicals Co., Ltd.) = 5/1 (solid weight ratio) surface treatment agent 1.2 g / m ² (solid content on both sides of the base paper) After applying to weight and drying, neutral newspaper printing paper with a basis weight of 43g / m ² was manufactured by high-temperature soft nip calendering at 120 ° C and linear pressure of 20kgf / cm. Indicated.

[Example 26]
Neutral newsprint paper was produced in the same manner as in Example 25 except that Example KP2 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Example 27]
Neutral newsprint paper was produced in the same manner as in Example 25 except that Example KP3 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Example 28]
Neutral newsprint paper was produced in the same manner as in Example 25 except that Example KP4 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Comparative Example 30]
Neutral newsprint paper was produced in the same manner as in Example 25 except that Comparative Example KP1 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Comparative Example 31]
Neutral newsprint paper was produced in the same manner as in Example 25 except that Comparative Example KP2 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Comparative Example 32]
Neutral newsprint paper was produced in the same manner as in Example 25 except that Comparative Example KP3 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Comparative Example 33]
Neutral newsprint paper was produced in the same manner as in Example 25 except that Comparative Example KP4 was used instead of Example KP1. The paper quality results are shown in Table 9.

[Comparative Example 34]
Neutral newsprint paper was produced in the same manner as in Example 25 except that Comparative Example KP5 was used instead of Example KP1. The paper quality results are shown in Table 9.

In the acid newspaper printing paper, Examples 21 to 24 containing KP adjusted to a desired freeness by bubbles generated by cavitation are used in Comparative Example 25 containing unbeaten KP and KP beaten by mechanical force. Compared to Comparative Examples 26 to 29 containing, the following is understood.
(1) Low density and bulky, high initial pure bending stiffness and excellent rigidity.
(2) The smoothness is high and the ink deposition property is excellent.
These trends are clearer when comparing Example 24 and Comparative Examples 26 and 27, in which KP contains almost the same KP.
In the case of neutral newspaper printing paper, the above-mentioned (1) and (2) are also apparent in Examples 25-28 as compared with Comparative Examples 30-34. In addition, it turns out that Examples 25-28 which are neutral newspaper printing paper have whiteness higher than Examples 21-24 which are acidic newspaper printing paper.

[Example 29]
Wastepaper DIP (CSF = 90ml, whiteness 60.2%, opacity 83.0%) / MP1 / NKP for example (CSF = 200ml, whiteness 83.0%, opacity 65.0%) = 75/18/7 (solid content (Weight ratio) mixed pulp slurry, 1.5% sulfuric acid band to pulp and 2% white carbon to pulp were added, using a twin wire type test paper machine, jet / wire ratio 101%, paper making speed 1,200 m / min The base paper was made with Hydroxyethylated starch (ETHYLEX2025, manufactured by Staley) / surface sizing agent (KN-520, manufactured by Harima Chemicals Co., Ltd.) = 5/1 (solid content weight ratio) surface treatment agent on both sides of the base paper 1.2 g / m ² ( After applying to solid weight and drying, high temperature soft nip calendering was performed at 120 ° C. with a linear pressure of 20 kgf / cm to produce acid newsprint paper with a basis weight of 43 g / m ² . It was shown to.

[Example 30]
Acid newsprint paper was produced in the same manner as in Example 29 except that Example MP2 was used instead of Example MP1. The paper quality results are shown in Table 10.

[Example 31]
Acid newsprint paper was produced in the same manner as in Example 29, except that Example MP3 was used instead of Example MP1. The paper quality results are shown in Table 10.

[Example 32]
Acid newsprint paper was produced in the same manner as in Example 29, except that Example MP4 was used instead of Example MP1. The paper quality results are shown in Table 10.

[Comparative Example 35]
An acidic newsprint paper was produced in the same manner as in Example 29 except that Comparative Example MP1 was used instead of Example MP1. The paper quality results are shown in Table 10.

[Comparative Example 36]
Acidic newsprint paper was produced in the same manner as in Example 29 except that Comparative Example MP2 was used instead of Example MP1. The paper quality results are shown in Table 10.

[Comparative Example 37]
Acid newsprint paper was produced in the same manner as in Example 29, except that MP3 for Comparative Example was used instead of MP1 for Example. The paper quality results are shown in Table 10.

[Comparative Example 38]
Acid newsprint paper was produced in the same manner as in Example 29, except that MP4 for Comparative Example was used instead of MP1 for Example. The paper quality results are shown in Table 10.

[Comparative Example 39]
Acidic newsprint paper was produced in the same manner as in Example 29 except that Comparative Example MP5 was used instead of Example MP1. The paper quality results are shown in Table 10.

[Example 33]
Wastepaper DIP (CSF90ml, whiteness 60.2%, opacity 83.0%) / Example MP1 / NKP (CSF200ml, whiteness 83.0%, opacity 65.0%) = 75/18/7 (solid weight ratio) 10% light calcium carbonate was added to the mixed pulp slurry, and paper was made using a twin wire type test paper machine at a jet / wire ratio of 101% and a paper making speed of 1,200 m / min. Hydroxyethylated starch (ETHYLEX2025, manufactured by Staley) / surface sizing agent (LC123L, manufactured by Harima Chemicals Co., Ltd.) = 5/1 (solid content weight ratio) surface treatment agent on both sides of the base paper 1.2 g / m ² (solid content After applying to weight and drying, neutral newspaper printing paper with a basis weight of 43g / m ² was manufactured by high-temperature soft nip calendering at 120 ° C and linear pressure of 20kgf / cm. Indicated.

[Example 34]
Neutral newsprint paper was produced in the same manner as in Example 33, except that Example MP2 was used instead of Example MP1. The paper quality results are shown in Table 10.

[Example 35]
Neutral newsprint paper was produced in the same manner as in Example 33, except that Example MP3 was used instead of Example MP1. The paper quality results are shown in Table 10.

[Example 36]
Neutral newsprint paper was produced in the same manner as in Example 33, except that Example MP4 was used instead of Example MP1. The paper quality results are shown in Table 10.

[Comparative Example 40]
Neutral newsprint paper was produced in the same manner as in Example 33 except that Comparative Example MP1 was used instead of Example MP1. The paper quality results are shown in Table 10.

[Comparative Example 41]
Neutral newsprint paper was produced in the same manner as in Example 33 except that Comparative Example MP2 was used instead of Example MP1. The paper quality results are shown in Table 10.

[Comparative Example 42]
Neutral newsprint paper was produced in the same manner as in Example 33 except that Comparative Example MP3 was used instead of Example MP1. The paper quality results are shown in Table 10.

[Comparative Example 43]
Neutral newsprint paper was produced in the same manner as in Example 33 except that Comparative Example MP4 was used instead of Example MP1. The paper quality results are shown in Table 10.

[Comparative Example 44]
Neutral newsprint paper was produced in the same manner as in Example 33 except that Comparative Example MP5 was used instead of Example MP1. The paper quality results are shown in Table 10.

In acid newspaper printing paper, comparison between Example 29 and Comparative Example 36 containing substantially the same CSF MP, comparison between Example 30 and Comparative Example 37, comparison between Example 31 and Comparative Example 38, Example From the comparison between No. 32 and Comparative Example 39, the following can be understood.
(1) Low density and bulky, high initial pure bending stiffness and excellent rigidity.
(2) The smoothness is high and the ink deposition property is excellent.
Even for neutral newspaper printing paper, comparison between Example 33 and Comparative Example 40, comparison between Example 34 and Comparative Example 41, comparison between Example 35 and Comparative Example 42, comparison between Example 36 and Comparative Example 43 From the above, the above (1) and (2) are apparent. In addition, it turns out that Examples 33-36 which are neutral newspaper printing paper have whiteness higher than Examples 29-32 which are acidic newspaper printing paper.

It is the schematic of the cavitation jet type washing | cleaning apparatus used in the Example.

Explanation of symbols

1: Sample tank 2: Nozzle 3: Cavitation jet cell 4: Plunger pump 5: Upstream pressure control valve 6: Downstream pressure control valve 7: Upstream pressure gauge 8: Downstream pressure gauge 9: Water supply valve 10: Circulation valve 11: Drain valve 12: Temperature sensor 13: Mixer

Claims (7)

  In the step of recycling used paper, it contains deinked pulp in which bubbles generated by cavitation are brought into contact with the used paper pulp suspension to remove contaminants adhering to pulp fibers and ash. Newspaper printing paper.   The filler added to the paper stock includes at least one selected from heavy calcium carbonate, light calcium carbonate, and a light calcium carbonate-silica composite, and is made by a neutral papermaking method. Newspaper printing paper.   A newspaper-printed paper containing pulp prepared by bringing bubbles generated by cavitation into contact with a pulp suspension to a desired freeness.   4. The newsprint paper according to claim 3, wherein the pulp suspension prepared by bringing bubbles generated by cavitation into contact with the pulp suspension to a desired freeness is a deinked pulp suspension. .   4. The newsprint paper according to claim 3, wherein the pulp suspension prepared by bringing bubbles generated by cavitation into contact with the pulp suspension to a desired freeness is a kraft pulp suspension.   The newsprint paper according to claim 3, wherein the pulp suspension prepared by bringing bubbles generated by cavitation into contact with the pulp suspension to a desired freeness is a mechanical pulp suspension. The filler to be added to the paper stock contains at least one selected from heavy calcium carbonate, light calcium carbonate, and a light calcium carbonate-silica composite, and is made by a neutral papermaking method. The newspaper printing paper according to any one of 6.

Images