JP2011080164A - Wound paper for newspaper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide wound paper for newspaper, which, in detail, markedly reduces peeling of fibers by adhesive material (pitch) in printing by offset printing, etc., has high printing opacity and is suitably useful for offset ink rotary printing, especially cold offset rotary printing of steel belt method. <P>SOLUTION: The wound paper for newspaper for cold offset printing comprises used paper pulp as a main raw material. The ash content of the wound paper for newspaper is ≥5 mass% and ≤15 mass%. The wound paper for newspaper contains at least white carbon, silica-containing particles except white carbon and talc. Fiber orientation is regulated so that a paper breaking rate is ≥343 cm/s when the surface of the wound paper for newspaper is tested by acceleration in the direction from end to start of winding of the wound paper in [paperboard-paper coming-off test method-acceleration printing method by an electric IGT tester] based on JIS P 8129. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a web for newspaper, and more specifically, to offset ink rotary printing with greatly reduced troubles that fibers are peeled off due to an adhesive (pitch) during printing by offset printing or the like, and having high printing opacity. The present invention relates to a suitably used newspaper web. More particularly, the present invention relates to a web for newspapers that reduces a peeling trouble in a steel belt type cold offset rotary printing press.

  In recent years, the use of waste paper has been promoted in consideration of environmental problems such as effective use of resources and conservation of forest resources, and deinked waste paper pulp (DIP) produced by removing ink from waste paper as a raw material for newsprint. ) Is used, and the blending ratio has reached 50% or more on average. In addition to newsprint paper, miscellaneous paper, books, and the like are used as general DIP raw materials used for such newsprint paper, and thus the manufactured DIP has a hot melt, an adhesive used for sealing, and the like. An adhesive substance (pitch) is mixed.

  On the other hand, an offset rotary press is used today for newspaper printing, and newspaper paper fed from a roll set in a paper feeding unit is supplied to the printing unit, printed by the printing unit, and the rail frame unit is used. Then, it is supplied to the folding part and processed into a state where it is delivered to the reader in the folding part. In this printing unit, since stable printing cannot be performed unless the tension applied to the newsprint is constant, the paper feeding unit is provided with a brake device for adjusting the paper feeding tension. There are shaft end brake system, steel belt system, etc. as this brake device, but when printing newspaper paper containing DIP as raw material on a steel belt type rotary press, adhesion of adhesive substances to the steel belt, or adhesive parts There is a problem in that a phenomenon occurs in which the fibers peel off, and further, a paper break occurs.

  Therefore, as a method for preventing such adhesion trouble, (a) a method of adding a predetermined polymer or a surfactant (see Japanese Patent Application Laid-Open No. 58-13795) at the stage of producing DIP, or (b) talc. A method of adding a pitch adsorbent such as clay and adsorbing to pitch particles to reduce the adhesiveness and adhesion of the pitch, and further incorporating this into paper as an inorganic filler (Japanese Patent Laid-Open No. 59-105842) Have been developed).

  However, according to the conventional method (a), the pitch can be dispersed by a surfactant or the like, but the surfactant tends to agglomerate with substances having different ionicity and the effect is lost, resulting in an increase in cost. It becomes a factor that obstructs the closure of water used in the papermaking process. In addition, according to the conventional method (b), pitch adsorbents such as talc are inexpensive, but pitch adsorptivity is not always sufficient, and pitch agglomeration and enlargement are not effectively suppressed. However, if a relatively large amount of pitch adsorbent is added to suppress the aggregation of pitch, the strength of the paper is reduced, and talc and the like have a low effect of improving printing opacity. There are problems such as inability to obtain transparency.

JP 58-13795 A JP 59-105842 A

  The present invention relates to a web for newspaper, and more specifically, to offset ink rotary printing with greatly reduced troubles that fibers are peeled off due to an adhesive (pitch) during printing by offset printing or the like, and having high printing opacity. An object of the present invention is to provide a suitably used web for newspaper. In particular, it is intended to provide a web for newspapers that can greatly reduce peeling troubles, particularly paper breakage, in a steel belt type cold offset rotary printing press.

  In the papermaking process, the present inventor not only studied the type of pitch adsorbent to be blended, the particle size, the blending amount, the blending ratio, etc., but also used steel belts to reduce peeling troubles in a rotary press equipped with a steel belt. It was assumed that the ease of peeling of pulp fibers on the contact surface of the newspaper web also had an influence. It contains white carbon and silica-containing particles other than white carbon and talc, and at the contact surface between the steel belt and the newspaper web, the end of the fiber on the contact surface is caused by the friction of the steel belt and is unlikely to peel off from the contact surface. In addition to the effect of adjusting the fiber orientation in the thickness direction of the paper to reduce the size of the adhesive (pitch) while maintaining high printing opacity, it can effectively suppress the enlargement due to pitch aggregation The present inventors have found that even when the steel belt comes into contact with the adhesive, the fibers are less likely to be caused by friction and the trouble of the fibers peeling off is reduced.

  The present invention relates to a newsprint web for cold offset printing using waste paper pulp as a main raw material, wherein the newsprint web has an ash content of 5% by mass or more and 15% by mass or less. In the “paperboard-paper peeling test method-accelerated printing method using an electric IGT tester” in accordance with JIS P 8129, which includes silica-containing particles other than carbon and white carbon, and talc, A newspaper web which is characterized in that the fiber orientation is adjusted so that the breaking speed of the paper tested so as to accelerate in the winding start direction from the winding edge is 343 cm / s or more.

  The newspaper web is mainly made of waste paper pulp, has an ash content of 5% by mass or more and 15% by mass or less, and contains white carbon, silica-containing particles other than white carbon and talc as fillers so as to achieve the ash content. The filler containing white carbon, silica-containing particles, and talc is effectively adsorbed to the sticky material, and the pitch dispersion can be reduced and the pitch can be prevented from becoming too large due to excessive aggregation. In addition, by providing silica-containing particles and white carbon having a high oil absorption property, an extremely high oil absorption property and high printing opacity can be obtained.

  In the “paperboard-paper peeling test method—accelerated printing method using an electric IGT tester” in accordance with JIS P 8129, the newspaper web is accelerated so as to accelerate the surface of the newspaper web from the winding edge to the winding start direction. Since the fiber orientation was adjusted so that the paper breaking speed was 343 cm / s or more, the contact surface was contacted by friction on the contact surface with the steel belt when printed as newspaper web on a rotary press equipped with a steel belt. The fiber viewed in the thickness direction of the paper is buried from the winding start direction of the paper take-up toward the winding edge so that the end of the fiber is not peeled off from the contact surface caused by the steel belt. Arranged. Therefore, when printing on a rotary press equipped with a steel belt as a newspaper web, even if the steel belt and the adhesive are in contact with each other, the fibers around the adhesive are not easily removed, and peeling troubles and paper breakage are less likely to occur. . Here, the “winding start direction” of the winding paper refers to the direction fixed to the paper tube at the winding center, and the “winding edge direction” refers to the outer peripheral edge at the end of winding. Further, the surface of the web means a surface that is visible from the outside on the surface of the web.

  The silica-containing particles may be silica composite regenerated particles in which silica is compounded on the surface of regenerated particles mainly made of deinking floss or papermaking sludge. Since the silica composite regenerated particles have a porous shape on the surface and the regenerated particles are cationic, the newspaper web has a pitch control effect and can exhibit an extremely high oil absorption function. Opacity can be further increased due to high light scattering properties. Further, the production cost can be reduced by using the regenerated particles whose main raw material is the deinking floss or papermaking sludge as the silica-containing particles.

  As the talc, a cation-treated talc whose surface is surface-treated with a cationizing agent may be used. Thus, by using a cation-treated talc surface-treated with a cationizing agent, the adsorptivity of talc to the pitch surface mixed in the raw material is further improved in the papermaking process, coupled with white carbon and silica-containing particles, The pitch can be dispersed and reduced in diameter, and the enlarging due to the aggregation of the pitch can be suppressed, and as a result, the pitch trouble can be further prevented in the printing process.

A surface sizing agent comprising starch and a styrenic polymer is preferably applied to at least the surface of the web for newspaper. The solid content coating amount of this surface sizing agent is 0.1 g / m ² or more to 1.0 g / m ² per side. m ² or less is preferable. Thus, by applying a surface sizing agent consisting of starch and a styrenic polymer on the surface in the above coating amount range, the surface smoothness of the newspaper web is improved, and the surface friction coefficient is reduced, As a result, coupled with the reduction in the pitch of the pitch, it is possible to prevent the offset printing apparatus from being caught on a steel belt or the like, and to further reduce peeling trouble due to the pitch.

Here, the “ash content rate” is a measured value based on “paper, paperboard and pulp-ash content test method—525 ° C. combustion method” described in JIS P 8251.
In addition, the “paper tearing speed” is based on “paperboard-paper peeling test method—accelerated printing method using an electric IGT tester” described in JIS P 8129, and is tested using standard ink with tack value 18. This is the printing speed when the printed newsprint tears.
The “particle diameter” of the filler is a volume average particle diameter measured by a laser analysis type particle size distribution apparatus “SALD-2200 type” (manufactured by Shimadzu Corporation).

  As described above, the web for newspaper of the present invention has a high printing opacity, can reduce the pitch in the paper making process, can effectively suppress the enlarging due to the aggregation of the pitch, and can further offset printing. Since the fiber orientation is adjusted so that the end of the fiber on the contact surface is not easily peeled off from the contact surface caused by friction on the contact surface with the steel belt, the pitch is removed in the offset printing process of newspapers. In particular, it is possible to suppress the problem of fiber peeling due to the steel belt, and it is possible to significantly reduce paper breakage.

1 is a schematic diagram of a production facility for regenerated particles or regenerated particle aggregates preferably used in the present invention. It is a schematic diagram of a 2nd combustion furnace, (a) is a longitudinal cross-sectional view, (b) is an expanded view of an inner surface.

  The web for newspaper according to the present invention is for cold offset printing, contains raw material pulp mainly composed of waste paper pulp and filler, and contains other optional components.

(Raw pulp)
The raw material pulp of the newspaper web includes main component waste paper pulp and optional component virgin pulp.

  Waste paper pulp, for example, tea waste paper, craft envelope waste paper, magazine waste paper, newspaper waste paper, flyer waste paper, office waste paper, corrugated waste paper, upper white waste paper, Kent waste paper, imitation waste paper, ground ticket waste paper, etc. Examples include disaggregation / deinked waste paper pulp (DIP) and disaggregation / deinking / bleached waste paper pulp.

  Among these waste paper pulp, newspaper waste paper pulp derived from newspaper waste paper, magazine waste paper pulp derived from magazine waste paper, and the like are preferable, and it is particularly preferable to use a mixture of newspaper waste paper pulp and magazine waste paper pulp. Such waste paper pulp and magazine waste paper pulp has a high recovery rate of waste paper, and the paper pulp types and fillers that make up news paper and magazine paper are similar in each paper maker, thus suppressing fluctuations in the raw material composition. It is suitable at the point which can do. In particular, wastepaper pulp is generally 50% or more of wastepaper pulp already contained in newsprint, and the content of virgin mechanical pulp and kraft pulp is low. Since it is paper-made and used paper pulp is formed by used paper processing, its properties are particularly preferable in that it has uniform properties and has almost constant properties.

Examples of virgin pulp include hardwood bleached kraft pulp (LBKP), softwood bleached kraft pulp (NBKP), hardwood unbleached kraft pulp (LUKP), conifer unbleached kraft pulp (NUKP), hardwood semi-bleached kraft pulp (LSBKP), conifer Chemical pulp such as semi-bleached kraft pulp (NSBKP), hardwood sulfite pulp, coniferous sulfite pulp;
Stone Grand Pulp (SGP), Pressurized Stone Grand Pulp (PGW), Refiner Grand Pulp (RGP), Thermo Grand Pulp (TGP), Chemi Grand Pulp (CGP), Ground Pulp (GP), Thermo Mechanical Pulp (TMP), etc. Of mechanical pulp;
Various known pulps such as pulps chemically or mechanically produced from non-wood fibers such as kenaf, hemp, and straw can be used.
Among these virgin pulps, mechanical pulp (MP) having an effect of complementing the reduction in bulk caused by using waste paper pulp in the production of newsprint is preferable, and thermomechanical pulp suitable for the adjustment of waste paper pulp obtained from waste paper (TMP) is preferred.

  The content of the used paper pulp in the raw material pulp is preferably 50% by mass or more, particularly preferably 70% by mass or more, and further preferably 80% by mass or more. By setting the content of the used paper pulp in the raw material pulp within the above range, environmental properties such as effective use of resources are improved, and offset printing suitability such as ink fillability is also improved. Conversely, the content of virgin pulp in the raw material pulp is preferably 20% by mass or more. When the content of virgin pulp is less than the above range, it is difficult to adjust the waste paper pulp obtained from the waste paper, and the newspaper paper does not become bulky and has a low waist, which may deteriorate the transportability and workability.

(Filler)
The newspaper web contains a filler so that the ash content falls within a predetermined range. Thus, the ash content based on JIS P 8251 of the entire newspaper web to be adjusted by containing a filler is set to 5% by mass to 15% by mass, and 6% by mass to 13% by mass. Is particularly preferred. If the content of the filler is small and the ash content of the entire newspaper web is smaller than the above range, the effect of suppressing the enlargement due to the aggregation of the pitch is small, and sufficient opacity is difficult to be obtained, which causes the show-through. There is a fear. Conversely, if the content of the filler is large and the ash content of the entire newspaper web exceeds the above range, the effect of suppressing the agglomeration and enlargement of the pitch is great, but the entanglement of the pulp fibers is inhibited, and the newspaper web There is a risk that the strength of.

  In addition, since the said newsprint uses the waste paper pulp as a main raw material, it necessarily contains the ash content from a waste paper. Although most of the ash derived from waste paper is discharged out of the system in the process of reclaiming waste paper pulp from waste paper, fine ash components that are physically or chemically fixed to the fiber remain in the waste paper pulp. It is obtained by being used as a papermaking raw material, and has a higher adhesiveness with raw material pulp than virgin filler, and therefore brings about a synergistic effect of improving ink fixing properties when performing offset printing.

  The newspaper web contains white carbon as a filler, silica-containing particles other than white carbon having an average particle size smaller than the average particle size of the white carbon, and talc.

  Examples of the white carbon used in the present invention include wet silica, calcium silicate, aluminum silicate and the like, which are generally used for papermaking as a highly oil-absorbing filler.

White carbon improves opacity due to the formed porous aggregate structure, but in particular, the apparent specific gravity is 0.10 to 0.25 g / ml, and the BET specific surface area is 100 to 250 m ² / g. The oil absorption according to JIS-K5101-13-1 is preferably 190 to 230 ml / 100 g.

  The average particle diameter of white carbon is 15 μm or more and 25 μm or less, preferably 18 μm or more and 22 μm or less. The primary particle diameter of white carbon is smaller than the above average particle diameter (for example, about 0.01 μm or more and 0.05 μm or less), but usually aggregates in a higher order to form secondary particles. The average particle diameter of white carbon in the present invention also refers to the average particle diameter of the aggregated secondary particles.

  If the average particle size of white carbon is smaller than the above lower limit, it becomes smaller than the mesh size of the mesh structure created by the pulp fibers, so the proportion of particles passing through this portion increases and the fixing rate decreases. . On the contrary, when the average particle diameter of the white carbon exceeds the above upper limit, it becomes larger than the mesh size of the mesh structure formed by the pulp fibers, so that it is difficult to enter and fix this portion.

  The average particle diameter of silica-containing particles other than white carbon used in the present invention is 1.7 μm or more and 12.5 μm or less, preferably 6.4 μm or more and 11.0 μm or less. When the silica-containing particles have an average particle size in the above range that is smaller than the average particle size of white carbon, they can enter and adhere to the voids formed by pulp fibers and white carbon particles. Therefore, according to the newspaper, high opacity can be provided. If the average particle size of the silica-containing particles exceeds the above upper limit, the particle size is too large for the voids, so that the particles cannot enter the voids, resulting in a decrease in stickiness and thus contributing to an improvement in opacity. do not do. In addition, it is drawn into the paper after adsorbing to the pitch, and the surface smoothness of the newspaper is reduced, resulting in pitch troubles during offset printing, especially paper breakage, and the drying process etc. In some cases, the newspaper may drop off and accumulate in the apparatus. Conversely, if the average particle size of the silica-containing particles is smaller than the above lower limit, the particle size is too small for the voids, so it is easy to pass through the voids, the stickiness is reduced, and it is not incorporated into the paper, It circulates in white water and remains in the papermaking system, causing soiling in the system. In addition, when the particle diameter is small in this way, the light scattering action is small even if the particle size is fixed, so that the contribution to the improvement of opacity is small. Furthermore, since the strength is weak and easy to fall even if it is fixed, the rate of dropout in the manufacturing process increases, and dirt in the machine system in the manufacturing process is generated, thereby reducing machine operability.

  The average particle diameter of talc is 2 μm or more and 12 μm or less, preferably 3 μm or more and 10 μm or less, and more preferably 4 μm or more and 8 μm or less. If the average particle size of talc is smaller than the above lower limit, talc adsorbing a small pitch will not be made into the paper, but will circulate in the white water and remain in the paper making system, causing stains in the system. On the other hand, if the average particle size of talc exceeds the above upper limit, the particle size after adsorbed on the pitch is increased and incorporated into the paper, resulting in a decrease in the surface smoothness of the newspaper web. Peeling troubles due to the pitch during printing, in particular, paper breakage, etc., may occur, and there is a risk of dropping from the newspaper and accumulating in the apparatus during the drying process.

  As a minimum of the addition amount of white carbon, 0.5 mass% is preferred to raw material pulp, and 1.0 mass% is especially preferred. On the other hand, the upper limit of the amount of white carbon added is preferably 3.0% by mass, particularly preferably 2.0% by mass. If the amount of white carbon added is less than the above lower limit, the generated voids are too large and too large, so that the voids cannot be filled with silica-containing particles, and the function of improving opacity is low. Conversely, if the amount of white carbon exceeds the above upper limit, the amount of white carbon is too large for the size of the voids formed between the pulp fibers, so that it cannot be reliably embedded between the voids. There is a risk that more filler will fall off during production and use. Moreover, when there is too much addition amount of white carbon, the strength between pulp fibers will fall and paper strength will fall.

  The lower limit of the amount of silica-containing particles added is preferably 0.5% by mass, particularly preferably 1.5% by mass, and more preferably 2% by mass with respect to the raw material pulp. Moreover, as an upper limit of the addition amount of a silica containing particle, 5 mass% is preferable, 4 mass% is especially preferable, and 3 mass% is more preferable. When the addition amount of the silica-containing particles is smaller than the lower limit, the generated voids cannot be filled, and the function of improving opacity cannot be sufficiently exhibited. On the contrary, when the addition amount of the silica-containing particles exceeds the above upper limit, the addition amount is too large with respect to the volume of the generated voids, so that the solid fixation cannot be performed and the filler is dropped off. Furthermore, the increase in filler weakens the adhesion between pulp fibers, and as a result, the strength of the newsprint decreases.

  As a minimum of the addition amount of talc, 0.5 mass% is preferable with respect to raw material pulp, and 0.8 mass% is more preferable. Moreover, as an upper limit of the addition amount of talc, 3.8 mass% is preferable and 2.4 mass% is more preferable. If the amount of talc added is smaller than the above lower limit, the pitch agglomeration effect will be insufficient. Conversely, if the amount of talc added exceeds the above upper limit, the pitch agglomeration effect will increase, but adhesion between pulp fibers will increase due to an increase in filler As a result, the strength of the newsprint is reduced. Further, although slipping tends to be improved, the slipping effect becomes excessive, it becomes difficult to stabilize the running property of the paper during printing, the paper meanders, and printing trouble is likely to occur.

  By adding the amount of talc, silica-containing particles, and white carbon in the above range, it effectively adheres to the periphery of the pitch while having high opacity, and effectively suppresses pitch agglomeration and enlargement. Can do.

(Regenerated particles)
Next, composite particles composed of silica having excellent opacity and inorganic particles other than silica that are suitably used as silica-containing particles will be described. As the inorganic particles other than silica, it is preferable to use regenerated particles or regenerated particle aggregates because newspapers with higher opacity can be obtained. Composite particles consisting of silica and recycled particles or aggregates of recycled particles are different from the commonly used calcium carbonate, talc, and clay in their constituent components and shape, and have excellent opacity. The amount of filler used can be reduced while maintaining opacity. Furthermore, since the surface of the silica-containing particles has a porous shape, the silica-containing particles can have extremely high oil absorption performance and have a pitch control effect.

(Production process of regenerated particles and regenerated particle aggregates)
Recycled particles are deinked floss separated from pulp fibers in the deinking process of waste paper processing equipment that produces waste paper pulp, and paper sludge separated from paper mill wastewater as the main raw material, and the main raw material is dehydrated and dried. It is obtained through a combustion and pulverization process. For example, the manufacturing method described in Japanese Patent No. 3869455 can be used as the manufacturing method. When used as an internal filler, it is preferable to adjust the particle size by pulverizing the particle size to 1.0 to 10.0 μm by a known pulverization method. If the particle diameter is smaller than 1.0 μm, the yield is poor and it is not preferable because it easily becomes a foreign substance in the paper machine system. This is not preferable because there is a possibility.
Here, the particle diameter of the regenerated particles is a volume average particle diameter measured by a laser analysis type particle size distribution measuring apparatus “SALD-2200 type” manufactured by Shimadzu Corporation.

  The regenerated particles produced by the above method form a regenerated particle aggregate in which several individual particles are aggregated, and have an irregular shape such as a lump-like mass. Due to this irregularity, the thickness of the paper tends to be increased when it is contained in newsprint, and the printing opacity of the newsprint can be increased because of the highly opaque particles.

  These regenerated particles preferably contain calcium, silica, and aluminum in a mass ratio of 30 to 82: 5 to 40:13 to 30 in terms of oxides, and more preferably 40 to 60:25 to 40:18 to 25. It is a mass ratio. By including calcium, silica, and aluminum in a mass ratio of 30 to 82: 5 to 40:13 to 30 in terms of oxide, the specific gravity is light and excessive aqueous solution absorption is suppressed, so that the dehydration property in the dehydration process is good. It is.

  As a method for adjusting the calcium, silica, and aluminum oxide conversion ratio of regenerated particles or regenerated particle aggregates in the firing step, the main component is to adjust the raw material composition in the deinking floss, but drying and classification In the process and the baking process, it is possible to adjust the coating floss and the adjustment process floss with a clear origin by means of including in the process by spraying or by means of containing the incinerator scrubber lime.

  For example, neutral papermaking wastewater sludge and wastewater sludge from the coated paper manufacturing process are used to adjust calcium in recycled particles and inorganic particle aggregates, and white carbon as an opacity improver is used to adjust silicon. Wastewater sludge from newsprint manufacturing systems that contain a large amount of additives, papermaking drainage sludge that uses sulfuric acid bands such as acidic papermaking to adjust aluminum, and wastewater from high-quality papermaking processes that often use talc. Sludge can be used as appropriate.

[Attached process]
In order to obtain more stable quality in production facilities, it is preferable to classify the particle size of regenerated particles and regenerated particle aggregates uniformly in each step, and feed back coarse and fine particles to the previous step. In this way, quality can be further stabilized.

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

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

[Silica composite regenerated particles, silica composite regenerated particles aggregate]
In the present invention, fillers generally used for papermaking, that is, silica composite inorganic particles in which calcium carbonate (heavy and light), clay, talc and the like are combined with silica are used. Preferably, the use of silica composite regenerated particles or silica composite regenerated particle aggregates in which the surfaces of the regenerated particles or regenerated particle aggregates are combined with silica results in higher bulkiness and higher opacity. The newsprint that you have can be obtained.

  As a suitable measure for precipitating silica on the regenerated particles or regenerated particle aggregates, the method described in Japanese Patent No. 3907688 or Japanese Patent No. 393596 can be used. However, it is preferable to carry out as follows because silica composite regenerated particles or silica composite regenerated particle aggregates having better opacity can be obtained.

<Silica composite particles>
Next, the silica composite particles of the present invention will be described in more detail while taking the silica composite regenerated particles as an example and showing the production method.

(Silica composite treatment process)
As described above, regenerated particles mainly made of paper sludge and deinking floss are added to and dispersed in an alkali silicate aqueous solution, and a mineral acid is added in a temperature range of 50 ° C. to 100 ° C. while stirring. . More preferably, it is added in at least two stages to carry out a silica composite reaction.

  The particle size suitable for the filler use etc. of the regenerated particle of this form is 1.0 μm to 10.0 μm. The particle diameter of the regenerated particles after the pulverization step is a volume average particle diameter measured by a laser analysis type particle size distribution measuring apparatus “SALD-2200 type” manufactured by Shimadzu Corporation.

  If the particle size of the regenerated particles is excessively smaller than 1.0 μm, a sufficient particle size may not be obtained at the time of silica composite, and there is a possibility of clogging into a glass shape when silica is composited. Within the scope of the present invention, the silica composite reaction can be sufficiently promoted. On the other hand, if the particle size is excessively large, excessively regenerated silica composite particles are likely to be produced, and the opacity may be lowered.

  Silica composite is a reaction operation for generating silica sol particles having a particle diameter of 10 to 20 nm (measured particle diameter by a scanning electron microscope) on the surface of regenerated particles. The particle size of the silica sol particles can be controlled by the stirring conditions during the reaction, the addition conditions of the mineral acid, and the like.

  The present inventors have surpassed the knowledge that the pore volume of all fine pores of the internally added fine particles has been regarded as an index of oil absorption and opacity, and the actual oil absorption is only the pore volume of inorganic fine particles. In addition, the silica composite regenerated particles that can be suitably used in the present invention have been found to have a high contribution of the ability to retain oil between the particles of inorganic fine particles. It has been found that pores of 1,000 angstroms or less greatly contribute to the substantial oil absorption.

  The pore volume of the silica composite regenerated particles obtained in the present invention is a measured value using a mercury intrusion porosimeter (“PASCAL 140/240” manufactured by Terumo), and the pore volume in a region of 10,000 mm or less is 0.00. 5 to 1.5 cc / g, preferably 0.68 to 1.45 cc / g, more preferably 0.70 to 1.35 cc / g.

  When the pore volume of the pores in the region of 10,000 mm or less is less than 0.5 cc / g, sufficient oil absorption cannot be expressed, and when it exceeds 1.5 cc / g, the oil absorption is improved. Decrease in opacity is likely to occur.

  In a preferred embodiment of the present invention, the particle diameter of the obtained silica composite regenerated particles is set in the range of 1.7 to 12.5 μm, and the ratio of silica in terms of oxide contained in the silica composite regenerated particles is set. By setting it as 10.0-50.0 mass%, the high oil absorption and the opacity improvement effect can be acquired. Moreover, it can adsorb | suck with a pitch and can disperse | distribute in paper effectively.

Although it does not specifically limit regarding alkali silicate aqueous solution, A sodium silicate solution (No. 3 water glass) is desirable at the point which is easy to acquire. The concentration of the alkali silicate solution is preferably 3 to 10% by mass in terms of the silicic acid content in the aqueous solution (in terms of SiO ₂ ). The composite of the regenerated particles and silica formed when the amount exceeds 10% by mass is not an inorganic fine particle / silica composite aggregate, but the regenerated particles are coated with white carbon, and the porosity of the regenerated particles in the core part, There is a risk that the optical properties may not be exhibited. On the other hand, if the amount is less than 3% by mass, the silica component in the composite particles is lowered, so that it is difficult to form regenerated particles coated with silica.

  The slurry concentration in the case where a regenerated particle or regenerated particle aggregate is added to and dispersed in an alkali silicate aqueous solution to prepare a slurry is preferably 8 to 14% by mass. By adjusting the slurry concentration, the particle size of the silica composite regenerated particles of the regenerated particles to be formed is controlled, and at the same time, the composition ratio of the regenerated particles and silica is adjusted. Mineral acids used in the present invention include dilute sulfuric acid, dilute hydrochloric acid, dilute nitric acid and other mineral acids, and dilute sulfuric acid is the most desirable in terms of price and handling. Furthermore, when using dilute sulfuric acid, it is preferable to add the mineral acid at a concentration of about 4 to 10 N in terms of production efficiency and composite silica homogeneity. If it is less than 4N, the reaction is slow, and if it exceeds 10N, a local reaction occurs, and there may be a problem that amorphous composite particles that are unevenly distributed are likely to be generated. Moreover, since silica precipitates in a short time, so that there is much mineral acid addition amount, it is desirable to adjust an addition rate according to those conditions. Addition within 5 minutes makes the structure of the uniform reaction system insufficient.

  Since the regenerated particles or regenerated particle aggregates preferably used in the present invention contain calcium, aluminum, and silica as constituent elements, addition of an excessive concentration of mineral acid may cause alteration of the regenerated particles.

  As described above, the present invention adds and disperses an aqueous solution of alkali silicate to a regenerated particle or regenerated particle aggregate at a solid content ratio of 100: 5 to 100: 20 to form a slurry, while stirring. In the temperature range of 50 to 100 ° C., the mineral acid is added in at least two stages to perform a silica composite reaction.

  When the ratio of the alkali silicate aqueous solution to the regenerated particles or the regenerated particle aggregate is less than 100: 5 in terms of solid content, the silica composite effect of the obtained silica composite regenerated particles is low, and the effect of improving opacity is difficult to obtain. If the ratio exceeds 20, the amount of oil absorption increases and the ink absorbency is high, so that the ink sinks, so-called poor color developability may occur.

  In the step of adding the regenerated particles to the alkali silicate aqueous solution, the temperature of the alkali silicate aqueous solution can be heated to a temperature of 50 ° C. or higher, and then heated. When the porous regenerated particles are added in a state where the temperature of the aqueous alkali silicate solution is heated to 50 ° C. or higher in advance, the fluidity by heating is improved, so that the slurry can be easily homogenized. A homogeneous mixed slurry of alkali silicate and regenerated particles can be obtained.

On the other hand, after preparing a homogenized alkali silicate and regenerated particle slurry, the mixture can be heated and stirred. As a heat source in this case, a known heat source can be used. For example, by blowing live steam (for example, 13 kg / m ² , 120 ° C.) in the factory, the temperature raising time can be shortened, and the regenerated particle slurry can be used. It is possible to prevent the temperature from being reduced when added, and to rapidly increase the temperature and the reaction, thereby improving the production efficiency.

  Regarding the reaction temperature during the production of the silica composite regenerated particles in the present invention, a slurry temperature range of 50 to 100 ° C., particularly a slurry temperature range of 50 to 98 ° C. is desirable. As a result of intensive studies by the present inventors, the reaction temperature with the regenerated particles used in the present invention affects the formation of silica, the crystal growth rate, and the mechanical strength of the formed silica composite regenerated particles. When the reaction temperature is less than 50 ° C., the rate of silica formation / growth does not occur or is slow, the silica composite regenerated particles have poor silica composite properties, are difficult to combine sufficiently, and the composite is formed by the shearing force applied during the making of the filler-added paper. Fragile. If it exceeds 100 ° C., the reaction process becomes complicated because an autoclave must be used because it is an aqueous reaction. In addition, the reaction proceeds excessively to form a dense silica composite regenerated particle form, and the opacity of the resulting silica composite regenerated particle is lowered, making it difficult to achieve the intended purpose.

  In the present invention, it is desirable to add at least two stages of mineral acid and to control the temperature at that time. That is, the slurry temperature at the time of adding the mineral acid in the first stage is 50 to 75 ° C., and the slurry temperature at the time of adding the mineral acid after the second stage is at least 10 ° C. higher than that at the first stage. Is desirable. Specifically, the desirable temperature conditions are that the liquid temperature in the first stage is 50 to 75 ° C., the temperature in the second stage is 70 to 100 ° C. in accordance with the number of mineral acid addition stages, and 90 in the final stage of the reaction. The temperature is set to a temperature of not lower than 98 ° C. and not higher than 98 ° C. Under these temperature conditions, more uniform silica composite regenerated particles can be obtained.

  The pH of the final reaction solution is preferably 8.0 to 11.0, more preferably 8.3 to 10.0, and most preferably 8.5 to 9.0.

  In the production of white carbon obtained by reacting a conventional alkali silicate and mineral acid, in order to complete the reaction between the alkali silicate and the mineral acid, the mineral acid is added to the alkali silicate until the pH is 5.5 to 7.0. However, when mineral acid is added until the pH reaches 7.0 or less, the calcium component contained in the regenerated particles is easily changed to calcium hydroxide, and the resulting silica composite regenerated particles are obtained. This is not preferable because the particle diameter of the toner is excessively reduced, the shape becomes inhomogeneous, the yield on paper is reduced, the generation of paper dust, and sufficient opacity are difficult to obtain. When the pH exceeds 11.0, the reaction between the alkali silicate and the mineral acid becomes dull, and it becomes difficult for silica to be combined with the surface of the regenerated particles, so that it is difficult to obtain sufficient opacity.

  When the mineral acid is added in one stage, it is preferable to set the addition amount of the mineral acid so that it takes 40 minutes or more for the pH to decrease by one.

  In the present invention, as described above, the mineral acid is preferably added in two or more stages. In this case, it is preferable to uniformly add the mineral acid in each stage in order to obtain a homogeneous silica composite. In addition, after one stage of addition (addition until the mineral acid has a neutralization rate of 20 to 50% with respect to the aqueous alkali silicate solution), a holding time of about 5 minutes to 20 minutes is made, so that the silica complex reaction is performed. A holding state is provided, silica is uniformly combined on the surface of the regenerated particles, and the addition of the mineral acid in the second stage can further promote the layered composite of silica, so that the surface of the regenerated particles is more uniformly distributed. Silica can be composited.

  The addition amount of the mineral acid for one stage is preferably set so that it takes 10 minutes to 45 minutes in order to uniformly combine silica on the surface of the regenerated particles. Even when the mineral acid is added in two or more stages, it is homogeneous to set the addition amount so that it takes about 10 to 120 minutes for the pH of the mineral acid to decrease by 1 in the fluctuation of the pH. Preferred for silica composites.

  In the agitation in this reaction step, for example, an unreacted zone is not formed. Therefore, it is preferable to employ an agitation means such as generating a turbulent flow by reversing the agitation blade or providing a baffle plate in the agitation tank.

  The particle diameter of the resulting silica composite regenerated particles is 1.7 to 12.5 μm, more preferably 6.4 to 11.0 μm. When the particle diameter of the silica composite regenerated particles is less than 1.7 μm, the effect of silica composite cannot be sufficiently exhibited, and it is difficult to obtain the effect of improving the oil absorption and opacity. When the particle diameter of the silica composite regenerated particles exceeds 12.5 μm, in the present invention, it becomes close to the average particle diameter of white carbon, can not enter the voids formed by white carbon and pulp fibers, the fixing property is reduced, As a result, the opacity is hardly improved.

  The silica composite regenerated particles preferably contain calcium, silica and aluminum in a mass% ratio of 30 to 80:10 to 50: 7 to 20 in terms of oxide. This component analysis is a value obtained by performing elemental analysis at an acceleration voltage (15 KV) using an X-ray microanalyzer manufactured by Horiba, Ltd., and converting the component to oxide.

  The ratio of the silica component is preferably 41.0 to 49.0% by mass, and more preferably 42.0 to 48.0% by mass. If the silica component ratio is less than 10.0% by mass, the silica composite is not sufficiently formed, so that the oil absorption and opacity cannot be improved. If the silica component ratio exceeds 50.0% by mass, the silica component is fine. There may be a problem that the silica particles are excessively filled, resulting in a decrease in oil absorption and opacity.

  As an incidental effect of the silica composite, the whiteness is improved by the silica composite. Although white paper opacity tends to decrease due to whiteness improvement, by using silica composite regenerated particles with high oil absorption, absorption dry printing ink for newspaper printing can be held and dried on the paper surface, making it a lightweight newspaper The printing opacity of the paper can be further improved.

  By combining the silica with the regenerated particles, the interfiber bonding is moderately inhibited by the cationic property of the regenerated particles and the anionic property of the silica, and the bulkiness is exhibited.

(Use or application)
The silica composite regenerated particles of the present invention have a large specific surface area because the surface of the porous regenerated particles are originally composited with silica, and when this is used as a filler for internal addition, whiteness and opacity are high. You can also get paper.

  Furthermore, the oil absorption amount of the silica composite regenerated particles is preferably in the range of 50 to 180 ml / 100 g. This is because when the silica composite regenerated particles in this range are used as an internal filler, the silica composite regenerated particles in the paper layer absorb the ink, the organic solvent, etc. impregnated in the paper layer. This is because a decrease in printing opacity is suppressed, and the effect of preventing ink drying and blurring becomes conspicuous by absorbing the ink and the organic solvent. On the other hand, when the oil absorption is less than 50 ml / 100 g, the above effect is not sufficient, and the silica composite regenerated particles may tend to inhibit the ink absorption and drying properties. On the other hand, when the oil absorption exceeds 180 ml / 100 g, there is a case where the ink sinks and the so-called color developability is inferior due to high ink absorbability.

  The oil absorption amount of the silica composite particles can be adjusted by adjusting the reaction temperature, the addition time, the holding time, the pH, the viscosity, the combustion means of the regenerated particles used, the particle diameter, etc. in the silica composite reaction step. When the pore volume of 1,000 Å or less is adjusted to 0.5 to 1.5 cc / g, silica composite regenerated particles that exhibit high oil absorption and can improve paper opacity can be obtained. High opacity can be obtained in the silica composite regenerated particle-containing paper containing regenerated particles.

As mentioned above, the production method of the silica composite regenerated particles has been described in detail by taking regenerated particles as an example. Recycled particle aggregates instead of regenerated particles, and calcium carbonate conventionally used as a filler for papermaking applications (heavy and light) Silica composite inorganic particles can be produced using talc, clay or the like and internally added to newsprint.
Thus, the particle | grains which combined the silica can make a wire wear degree low, since the particle | grain surface is compounded with the silica, and can be used suitably as a filler. Inorganic particles added internally to paper, if the particles are hard, the wire (net part) of the paper machine is liable to be damaged, and the life of the wire is shortened. However, as in the present invention, the life of the wire can be extended by using inorganic particles composited with silica, preferably silica composite regenerated particles or silica composite regenerated particle aggregates, which are soft inorganic particles that do not easily damage the wire.

  The degree of wire wear can be evaluated by a Filcon type wire wear degree test. When regenerated particle aggregates having an abrasion degree of about 80 mg are used as inorganic particles to be combined with silica, particles having a wear degree of about 20 to 70 mg can be lowered by the silica combination, and particles that can be sufficiently used as an internal filler. Can be obtained. In addition, the wire wear degree of heavy calcium carbonate is 100 mg or more, light calcium carbonate is about 50 mg, and white carbon is about 15 mg. If it is about 70 mg or less, it can be used as an internal filler.

  As described above, when composite particles composed of silica and inorganic particles other than silica, preferably silica composite regenerated particle aggregates are used as fillers, pitch is effectively dispersed, pitch trouble is reduced, and high opacity is achieved. It is preferable because it is possible to obtain newspapers having the same.

  As the filler contained in the newspaper web, silica-containing particles and white carbon and talc are essential. In addition, inorganic fillers such as clay, kaolin, titanium oxide, calcium carbonate, vinyl chloride resin, polystyrene resin, Organic fillers such as urea formalin resin, melamine resin, and styrene-butadiene copolymer resin can be used.

  As the talc, a cation-treated talc whose surface is treated with a cationizing agent may be used. Thus, by using a cation-treated talc surface-treated with a cationizing agent, the pitch mixed in the raw material generally has an anionic property. Further improved, coupled with the adsorption of white carbon, it is possible to further suppress the enlargement due to the aggregation of the pitch, and as a result, it is possible to further prevent the pitch trouble in the printing process.

  This cation-treated talc is generally obtained by reacting talc with a cationizing agent such as an organic cationic compound having an organic cationic group, and at least the talc surface is cationically charged. Examples of the cationizing agent include polyethyleneimine, polyvinyl pyridine, polyamine sulfone, polydialkylaminoethyl methacrylate, polydialkylaminoethyl acrylate, polydialkylaminoethyl methacrylamide, polydialkylaminoethyl acrylamide, polyepoxyamine, polyamidoamine, dicyandiamide. -Formalin condensate, dicyandiamide polyalkyl-polyalkylene polyamine condensate, compounds such as polyvinylamine, polyallylamine and their hydrochlorides, and further polydimethyldiallylammonium chloride and its acrylamide copolymer, polydiallylmethylamine hydrochloride And polymethacrylic acid ester methyl chloride quaternary salt.

(Other internal additives)
The newspaper web is not particularly limited. However, in order to develop physical properties such as tensile strength, tear strength, and elongation, paper strength enhancers, freeness / yield improvers, internal sizing agents, auxiliaries, etc. are necessary. It may contain.

(Fiber orientation)
In the present invention, the newspaper web is viewed in the thickness direction of the paper so that when printed on a rotary press equipped with a steel belt, fibers are caused by friction on the contact surface with the steel belt and are not easily separated. The fibers are arranged so that the fibers are buried from the winding start direction toward the winding bottom. In general, newsprint is dehydrated and dried through a press part and a dryer part after pulp slurry ejected to a wire part is wound around a spool roll by a reel part and processed into a wound paper by a winder. Newspaper paper wound up with a spool roll has a surface that is visible on the front side of the roll as the back surface of the paper (for example, the surface that contacts the bottom wire of the wire part in the gap former). Even after the spool roll is finished with a winder, the side visible from the outside is the back side of the paper. In addition, the wound paper is wound on a spool roll and rewound with a winder, so that the wound paper is wound in the direction opposite to the paper discharge direction (direction from the wire part to the reel part). In the case of printing on a printing press, the paper is unwound in the paper extruding direction. Adjustment of the fiber orientation in the thickness direction of the web for newspaper is to change the ratio of the jetting speed of the raw material (jet speed) to the wire speed (J / W ratio) and the degree of the landing point of the jet in the newsprint manufacturing process. Can be adjusted. The fibers on the contact surface between the steel belt and web of the rotary press are buried from the winding start direction of the web toward the bottom of the web so that the fiber ends are not easily peeled off by the steel belt during printing. In order to arrange the fibers in the fiber part, that is, it is only necessary to embed the fibers in the thickness direction of the paper from the wire part to the reel part. Just do it.

  Further, in the present invention, as a result of examining the fiber orientation index in the thickness direction of the paper, in the “paperboard-paper peeling test method—accelerated printing method using an electric IGT tester” in accordance with JIS P 8129, The surface was tested so as to accelerate in the winding start direction from the winding edge of the web, and it was found that there was a correlation between the speed at which paper breakage occurred and peeling troubles in a rotary press or paper breaks due to peeling. “Paperboard-paper peeling test method—accelerated printing method using an electric IGT tester” is a method of originally testing the peeling of paper and paperboard used for lithographic printing or letterpress printing. Evaluation is based on the printing speed when paper peeling starts on the surface, but in the present invention, in order to obtain a correlation with pitch breakage in a rotary press equipped with a steel belt, the fiber is completely broken using an ink with tack value 18 The printing speed was evaluated. The newspaper web was tested by accelerating from the winding edge of the web in the winding start direction in the “paperboard-paper peeling test method-accelerated printing method using an electric IGT tester” in accordance with JIS P 8129, and the paper was broken. The fiber orientation is preferably adjusted so that the speed is 343 cm / s or more. By adjusting the fiber orientation in this way, even when the pitch is taken by the steel belt, it is difficult to cause a fiber peeling trouble. When paper breakage occurs at 343 cm / s or less, the fiber viewed in the thickness direction of the paper is buried in the winding start direction from the winding tail of the web, or is buried to the winding tail from the winding start direction. For this reason, when printing as a newspaper web on a rotary press equipped with a steel belt, fibers are caused by friction on the contact surface with the steel belt, and a peeling trouble is likely to occur.

  In the present invention, the J / W ratio is preferably 1.025 to 1.050, more preferably 1.030 to 1.045. If the J / W ratio is smaller than the above lower limit, the degree of press formation is low or pulling formation occurs, and the fibers viewed in the thickness direction of the paper are buried in the winding start direction from the winding tail or winding Since the degree of burial from the starting direction toward the winding edge is low, when printing as a newspaper web on a rotary press equipped with a steel belt, there is a problem that the fibers are caused by friction on the contact surface with the steel belt, causing separation and tearing. Cheap. On the other hand, if the J / W ratio is higher than 1.050, dehydration at the wire part is deteriorated, which causes a reduction in paper making speed. In addition, when finishing the winding paper from the beginning of winding so that the winding edge direction is the same as the paper discharging direction (direction from the wire part to the reel part) by rewinding or the like, the fiber will be pulled. In addition, the ratio of the raw material ejection speed (jet speed) to the wire speed (J / W ratio) and the degree of the landing point of the jet are adjusted.

(surface treatment)
A surface sizing agent may be applied to at least the surface of the newspaper web. By applying the surface sizing agent, the surface smoothness of the newspaper web is improved, and the friction coefficient of the surface is reduced. It is possible to further prevent the trouble of peeling due to the pitch.

  Examples of the surface sizing agent include oxidized starch, etherified starch, esterified starch, enzyme-modified starch, cationized starch, carboxymethyl cellulose, hydroxyethyl cellulose, methyl cellulose, polyvinyl alcohol (PVA), styrene / acrylic acid copolymer, styrene / (Meth) acrylic acid copolymer (in addition, (meth) acrylic acid means “acrylic acid and / or methacrylic acid”), styrene / (meth) acrylic acid / (meth) acrylic acid ester copolymer Polymers, styrene / maleic acid copolymers, styrene / maleic acid half ester copolymers, styrene / maleic acid ester copolymers, water-soluble polymers such as polyacrylamide, alkyd resins such as rosin, tall oil and phthalic acid Anionic low content such as saponified products, saponified products of petroleum resin and rosin Compounds, such as cationic polymers, such as Isojianeto polymers and the like, which may be used alone or simultaneously. As a result, the vehicle of cold-set offset ink is quickly absorbed, and even if the amount of printing ink increases due to the speedup of a rotary press or the use of a tower press for double-sided color, sufficient absorption and drying properties are exhibited. Since the filler is securely fixed to the fiber, it is possible to prevent the filler from falling off and to ensure excellent printing opacity, printability and the like.

  Among these surface sizing agents, water-soluble polymers are preferable, and starch is particularly preferable. According to such a water-soluble polymer, while maintaining the bulkiness of the newsprint paper, the fibers and fibril fibers protruding from the newsprint paper surface are flattened. As a result, the steel belt of the offset printing apparatus is prevented from being caught, and depending on the pitch. Peeling trouble can be further reduced.

  In addition, as the oxidized starch used in the present invention, conventionally used modified starch is preferably exemplified, for example, by oxidation reaction with sodium hypochlorite or the like, low molecular weight, carboxyl group in the molecule, Examples include those introduced with an aldehyde group, a carbonyl group, and the like.

  In addition, as an average molecular weight of starch, 600,000-3 million are preferable and 800,000-2,800,000 are especially preferable. The starch having such an average molecular weight improves the absorption and drying properties by incorporating the solvent component into the paper while keeping the ink component on the paper surface, in addition to the coverage of the paper surface. Further, the viscosity (10%) of the starch is preferably 30 × 10 −3 Pa · s or less, particularly preferably 15 × 10 −3 to 25 × 10 −3 Pa · s. The starch having such a viscosity is reduced in penetration into the paper and can remain on the paper surface, thereby improving the surface smoothness of the newspaper web and reducing the catch on the steel belt.

Moreover, it is preferable to use a styrenic polymer together with starch from the viewpoint of further improving the size, compatibility with ink in offset rotary printing, and the effect of preventing the filler from falling off.
When oxidized starch and styrene-based polymer are used as the surface sizing agent, starch can be applied uniformly, and pitch peeling troubles on the steel belt are reduced due to the effect of improving the surface strength and preventing the filler from falling off. The blending ratio of oxidized starch and styrene-based sizing agent is preferably 10-15 parts of styrene-based sizing agent with respect to 100 parts of oxidized starch as solid content. If the styrenic size is less than 10 parts, it is difficult to sufficiently improve the size and surface strength of the paper, and if it exceeds 15 parts, the cost may increase and the opacity and ink drying may be reduced. is there.

  Examples of the styrenic polymer include a styrene / acrylic acid copolymer and a styrene / (meth) acrylic acid copolymer (wherein (meth) acrylic acid means “acrylic acid and / or methacrylic acid”). Examples include styrene / (meth) acrylic acid / (meth) acrylic acid ester copolymers, styrene / maleic acid copolymers, styrene / maleic acid half ester copolymers, styrene / maleic acid ester copolymers, and the like.

The solid content coating amount of the surface sizing agent of the newspaper web is preferably 0.1 g / m ² or more and 1.0 g / m ² or less per side, and 0.2 g / m ² or more and 0.75 g / m ² or less. Is particularly preferred. When the coating amount of the surface sizing agent is smaller than the above range, sufficient film property cannot be obtained, the surface smoothness is lowered, and the pitch and filler are easily taken by friction with the steel belt. On the other hand, if the coating amount of the surface sizing agent exceeds the above range, a large amount of mist of the coating liquid containing the surface sizing agent will be generated around the coating equipment, fouling the peripheral equipment, and paper breakage due to dirt There is a risk of paper defects. Therefore, by setting the coating amount of the surface sizing agent in the above range, the surface smoothness of the newspaper web is improved and the friction coefficient of the surface is reduced. As a result, white carbon, silica-containing particles, talc, etc. Combined with the dispersion and small diameter of the pitch due to the addition of, it is possible to reduce the catching of the offset printing apparatus on the steel belt and further reduce the peeling trouble due to the pitch.

  The means for applying the surface sizing agent is not particularly limited, and for example, a transfer roll coater, an air doctor coater, a blade coater, a rod coater or the like is used. Among these coaters, a transfer roll coater type coating apparatus is preferable, and a gate roll coater is particularly preferable. Unlike other coating methods, coating by the film transfer method, particularly gate roll, is suitable for forming a highly coatable layer on the surface of the newspaper web even with a low coating amount. Since no rapid shearing force is applied to the liquid, the coating liquid used for circulation is excellent in stability, and a uniform film can be obtained at high speed. As a result, when multicolor offset rotary printing is performed using, for example, a cold set type ink, it is excellent in printability such as ink density, ink setting property, and ink setting property.

  Further, the newspaper web can be flattened by a calendar facility such as a super calendar, a gloss calendar, or a soft calendar. By performing the flattening process using such a calendar facility, it is possible to further improve the printability of the newspaper web. The calender equipment is not particularly limited, but the newspaper web having a high proportion of waste paper pulp has the same tension at a low nip pressure, and has a high smoothness and consequently a light weight and excellent color printability. Is particularly preferred.

(The newspaper web)
A newspaper web for cold offset printing using waste paper pulp as a main material, wherein the newspaper web has an ash content of 5% by mass to 15% by mass, and the newspaper web has at least white carbon and white carbon. In addition to the silica-containing particles and talc, the filler and pitch containing talc, silica-containing particles, and white carbon are effectively adsorbed, the pitch is dispersed and reduced in size, and enlarging due to pitch aggregation is effectively suppressed. Furthermore, in the “paperboard-paper peeling test method—accelerated printing method using an electric IGT tester” in accordance with JIS P 8129, the surface of the newspaper web is tested so as to accelerate from the winding edge of the web in the winding start direction. By adjusting the fiber orientation so that the broken paper breaking speed is 343 cm / s or more, the peeling trouble due to the pitch in the offset rotary press equipped with the steel belt is remarkably reduced. Furthermore, it has high printing opacity by containing silica-containing particles other than white carbon and white carbon.

The basis weight of the newspaper web is measured in accordance with the “basis weight measuring method” described in JIS P 8124 from the viewpoint of weight reduction, for example, ensuring the paper quality strength in high-speed rotary printing and ensuring the printing opacity. , 38 g / m ² or more, more preferably 40 g / m ² or more, and from the viewpoint of weight reduction, the basis weight is preferably 48 g / m ² or less, more preferably 46 g / m ² or less. . If the basis weight is less than the above lower limit, for example, it is difficult to ensure the strength in a high-speed offset rotary printing press.

  The whiteness of the newspaper web is in accordance with “Method for measuring paper, paperboard and pulp-ISO whiteness (diffuse blue light reflectance)” described in JIS P 8148 so as not to cause eye strain of subscribers. Therefore, it is preferably from 52% to 57%, particularly preferably from 53% to 56%.

  The blank paper opacity of the newspaper web is required to have high opacity because it is difficult to see through during printing, but in accordance with “Paper Opacity Test Method” described in JIS P 8138. The measured lower limit is preferably 90%, particularly preferably 92%. The upper limit of the white paper opacity is preferably 95%, particularly preferably 94%. If the blank paper opacity is less than the above lower limit, the back-through tends to occur. On the other hand, when the blank paper opacity exceeds the above upper limit, the necessary filler is increased. As a result, the adhesion between the pulp fibers is lowered, and the strength of the newspaper web is lowered.

  The printing opacity of the newspaper web is required to have high printing opacity from the viewpoint that it is difficult for the print-through to occur during printing, but the lower limit measured in accordance with the printing opacity test method described later is 90%. Is preferred, with 91% being particularly preferred. Further, the upper limit of the printing opacity is preferably 95%, particularly preferably 94%. If the printing opacity is less than the above lower limit, show-through tends to occur. On the contrary, if the printing opacity exceeds the above upper limit, the necessary filler increases, resulting in a decrease in the adhesion between the pulp fibers, the strength of the newspaper web, or the loss of the filler from the paper surface. Not only the paper dust at the time of printing increases, but also dirt in the machine system in the manufacturing process increases and the operability deteriorates.

  The newspaper web is accelerated in the direction of winding from the winding edge of the web with respect to the surface of the paper web in the “paperboard-paper tear test method—accelerated printing method using an electric IGT tester” in accordance with JIS P 8129. In this way, the fiber orientation is adjusted so that the paper breaking speed tested is 343 cm / s or more, and coupled with the dispersion and diameter reduction of the pitch, there is a peeling trouble due to the pitch in an offset rotary press equipped with a steel belt. Remarkably reduced.

In addition, the density of the web for newspaper is measured in accordance with JIS P 8118 “Testing method for thickness and density” described in JIS P 8118 from the viewpoint of maintaining the strength associated with the recent weight reduction and weight reduction. It is preferably 0.50 to 0.80 g / cm ³ , more preferably 0.55 to 0.75 g / cm ³ .

In addition, the stiffness in the MD direction of the paper is measured in accordance with “a stiffness test method using a paper Clark stiffness tester” described in JIS P 8143, for example, in order to give a waist suitable for high-speed rotary printing. It is preferable that it is 30-55 cm < ³ > / 100, Furthermore, it is 32-50 cm < ³ > / 100.

(Method for manufacturing the web for newspaper)
In the following, a method for producing the newspaper web will be described. First, the raw material pulp is sent to the receiving chest in a slurry state and then sent to the blending chest. Next, the blended raw material of the blended chest is supplied to the machine chest and then guided to the seed box. The blended raw material adjusted here is supplied to the paper machine via the first fan pump, the cleaner, the screen, the second fan pump, and the head box. In addition, silica-containing particles and white carbon are added before being supplied to the second fan pump.

  Various additives are added at any stage from the raw pulp blending adjustment stage (receiving chest, blending chest and machine chest) to being supplied to the paper machine, preferably talc in the receiving chest and cation in the blending chest. After adding the ionic coagulant to stabilize the ionicity of the raw material pulp, the internal sizing agent is added in the seed box in the subsequent process, and then the cationic flocculant is added.

  By adding talc in the receiving chest, the pitch contained in the raw material pulp can be dispersed and reduced in diameter, and the increase in pitch due to aggregation can be effectively suppressed. The solid content of talc is preferably 5 to 38 kg / Pt, particularly preferably 8 to 24 kg / Pt, from the viewpoint of effectively suppressing the increase in pitch due to aggregation. Here, "kg / Pt" means the mass in terms of solid content kg per ton of raw pulp absolutely dry.

  By adding a cationic organic polymer coagulant in the compounding chest, the pitch can be effectively adsorbed on the talc to prevent the pitch from becoming too large and the ionicity can be easily adjusted in the subsequent process. Thus, the yield of filler can be improved.

  Examples of the cationic organic polymer-based coagulant include cationic polyacrylamide, polyvinylamine, polydiallyldimethylammonium chloride, polyethyleneimine, polyamine having a molecular weight of 50000 or more, polyamine modified by grafting of ethyleneimine, polyetheramide, Polyvinyl imidazole, polyvinyl pyrrolidine, polyvinyl imidazoline, polyvinyl tetrahydropyrine, poly (dialkylaminoalkyl vinyl ether), protonated or quaternized forms of poly (dialkylaminoalkyl (meth) acrylate) and adipic acid and polyalkylene polyamines, acrylamide or Copolymers of methacrylamide and dialkylaminoethyl acrylate or dialkylaminoethyl methacrylate (for example, Acrylamide and copolymers in the form quaternized with form or methyl chloride salt with hydrochloric acid and dimethylaminoethyl acrylate) and the like.

  Among these, as the cationic organic polymer-based coagulant, one or more amines selected from ammonia, primary amines, secondary amines and tertiary amines, a polycationic substance, and a molecular weight of 10,000 to 70,000. A polyalkyleneimine modified product obtained by reacting a polyalkyleneimine is preferred.

The solid content of the cationic organic polymer-based coagulant is preferably 0.1 to 1.0 kg / Pt (pulpton), particularly preferably 0.15 to 0.60 kg / Pt. If the amount of the cationic organic polymer-based coagulant is smaller than the above range, sufficient anion trash coagulation or ionic neutralization effect is not observed, and the effect of adding a sizing agent in the subsequent process is difficult to occur. Problems develop.
Conversely, if the amount of the cationic organic polymer-based coagulant exceeds the above range, the ionicity in the raw material pulp system becomes excessively cationic, causing unevenness in unnecessary coagulation and size effects, and excessive addition. However, there is a problem in that the yield of filler is deteriorated, and further, a poor texture is developed.
Further, in addition to the cationic organic polymer-based coagulant, an inorganic coagulant such as a sulfuric acid band can be added. The solid content of the inorganic coagulant is preferably 0.3 to 14 kg / Pt (pulpton), more preferably 0.5 to 8 kg / Pt, and particularly preferably 1.0 to 5 kg / Pt.

  The internal additive sizing agent can be added in any papermaking process as long as it is after the raw material pulp blending adjustment stage, but is most preferably added in a seed box. By adding the internal sizing agent in the seed box, uniform mixing with the raw material pulp is promoted, and uniform size can be obtained.

  Examples of the internally added sizing agent include rosin sizing agents, synthetic sizing agents, petroleum resin sizing agents, and neutral sizing agents. Among these, a neutral sizing agent is preferably used from the viewpoint of running properties in the printing apparatus and paper storage stability after printing.

  The addition amount of the solid content of the internally added sizing agent is preferably 0.12 to 0.45 kg / Pt, particularly preferably 0.24 to 0.30 kg / Pt. When the addition amount of the internal sizing agent is smaller than the above range, the paper as a whole cannot exhibit sufficient sizing properties even when the surface sizing agent is applied. On the other hand, if the amount of the solid content of the internally added sizing agent exceeds the above range, the sizing property also reaches a saturated state, and there is a possibility that defects due to reaction with other chemicals and dirt on each part of the paper machine during operation may occur. is there.

  By adding the cationic flocculant after the internal sizing agent is added, the fixing of the sizing agent to the pulp fiber can be promoted, and as a result, the size can be improved. The cationic flocculant is preferably added after the sizing agent, just after the first fan pump, the cleaner and the second fan pump through the screen.

  Specific examples of the cationic flocculant include a cationic polyamine resin, a cationic polyamine polyamide resin, a cationic polyacrylamide, a cationic modified starch, a styrene acrylic resin, and a cationic thermosetting resin. .

  The addition amount of the cationic flocculant is preferably 50 to 400 ppm, particularly preferably 80 to 200 ppm in terms of pure content. When the addition amount of the cationic flocculant is smaller than the above range, it becomes difficult to obtain the effect of improving the yield of talc, white carbon, silica-containing particles, and conversely, when the addition amount of the cationic flocculant exceeds the above range. , There is a risk that the texture will deteriorate. As such a cationic flocculant, for example, the average molecular weight is 8 million to 12 million, more preferably 8.5 million to 11 million, and the proportion of the cationic monomer is 5 to 100 mol%, preferably 10 to 100 mol. % Cationic water-soluble polymer or copolymer can be used. Typical examples of such cationic flocculants include PAM. If the average molecular weight of the cationic flocculant is less than 8 million, the effect using the cationic flocculant may not be sufficiently exhibited. On the other hand, if the average molecular weight is larger than 12 million, the desired effect cannot be improved much. There is a risk of high costs.

  The newspaper web is preferably coated with a surface sizing agent on both sides as described above after the paper making process. In addition, the newspaper web is a paperboard-paper peeling test method-accelerated printing method using an electric IGT tester according to JIS P 8129. The fiber orientation may be adjusted so that the paper breaking speed tested to accelerate is 343 cm / s or more. The fiber orientation can be adjusted by changing the ratio of the raw material ejection speed (jet speed) to the wire speed (J / W ratio), the landing point of the jet, and the like in the newsprint manufacturing process.

EXAMPLES Hereinafter, although this invention is explained in full detail based on an Example, this invention is not interpreted limitedly based on description of this Example.

Example 1
80% by mass of disaggregated / deinked waste paper pulp (DIP) and 20% by mass of thermomechanical pulp (TMP), and 120 mL freeness with a refiner. S. A pulp slurry adjusted to F (based on JIS P 8121) was obtained. After adding 15 kg / pulpton of cation-treated talc (average particle size 6 μm) to this pulp slurry and adjusting the pH to 6-7 with a sulfuric acid band, a cationic organic polymer coagulant (Himo Co., Ltd.) ) Made Himax SC924) was added at 0.4 kg / pulp ton in solid content. After adding 0.3 kg / pulp ton (solid content) of alkyl ketene dimer sizing agent (product name: AD-1624, manufactured by Nippon PMC Co., Ltd.) to 1 t of pulp solid content, this silica composite regenerated as silica-containing particles Particles (average particle size 8.5 μm) were added at 30 kg / pulpton, and white carbon (manufactured by Elle Paper Chemical Co., Ltd., average particle size 20 μm) was added at 15 kg / pulpton. Next, 110 ppm of a flocculant (Himo Rock ND270 manufactured by Hymo Co., Ltd.) was added to the absolutely dried pulp, and a base paper having a basis weight of about 42.5 g / m ² was obtained using a twin wire paper machine. Furthermore, as a surface sizing agent, oxidized starch and styrene polymer (SS2712 manufactured by Starlight PMC Co., Ltd.) were mixed with 100 parts of oxidized starch so that the styrene polymer was 30 parts, and the concentration was adjusted by adding water. A liquid was prepared and coated with 1.0 g / m ² per side in terms of dry mass to obtain newsprint. Next, the obtained newsprint was finished with a winder to obtain the newsprint web of Example 1. The web is wound in the direction opposite to the paper discharge direction, and the rotary press is unwound in the discharge direction. In addition, the silica composite reproduction | regeneration particle | grains used in Example 1 were manufactured according to the below-mentioned manufacture example, and the manufacture example 1-1 of Table 3 was used. Further, papermaking was performed at a ratio of the raw material ejection speed (jet speed) and the wire speed (J / W ratio) of 1.035.

[Production of regenerated particles]
As the material to be processed (raw material), papermaking sludge or deinking floss is used in advance, and after the dehydration process, the manufacturing equipment shown in FIGS. 1 and 2 performs the organic component heat treatment process under the conditions shown in Table 1. A wet pulverization process was performed sequentially using the 1st combustion process and the 2nd combustion process as appropriate to obtain regenerated particles. The internal heat kiln used in the heat treatment process of the organic components in Production Examples 2 and 3 and Production Examples 6 and 7 is an internal heat kiln furnace in which the main body is placed horizontally and rotates around the central axis. The paper flow sludge was supplied from the raw material supply port and hot air was blown into it.

  The internal heat kiln used in the first combustion process is an internal heat kiln furnace in which the main body is placed horizontally and rotates around the central axis. Furthermore, the external heat kiln furnace used in the second combustion process is an external heat kiln furnace in which the main body is placed horizontally and rotates around the central axis, and as this external heat kiln furnace, an external heat having a parallel lifter in particular is provided. An electric kiln furnace was adopted. The wet pulverization process was performed using a ceramic ball mill. The deinking floss in Production Example 4 was used by separating it before the high-grade used paper deinking floss was mixed in the papermaking sludge.

  As the primary combustion temperature, the primary combustion furnace outlet temperature was measured. The secondary combustion temperature was measured at the secondary combustion furnace outlet temperature. As for the oxygen concentration, the primary combustion furnace outlet oxygen concentration and the secondary combustion furnace outlet oxygen concentration were measured.

[Production of silica composite regenerated particles]
Under the conditions shown in Table 2, 38% concentration of sodium silicate solution (No. 3 water glass) and 20% concentration of regenerated particle slurry were mixed as an aqueous solution of alkali silicate, diluted water was added, and it was composed of alkali silicate and regenerated particles as shown in Table 2. After adjusting the slurry to a predetermined reaction initiation concentration and reaction initiation pH, sulfuric acid having a prescribed degree was added as a mineral acid and stirred to produce silica composite regenerated particles. A known mixer is used for stirring the slurry. The pH of the slurry was measured with a pH meter manufactured by Horiba, and the reaction temperature was measured with a known thermometer. In the primary reaction step, the mineral acid was added so that the neutralization rate between the alkali silicate aqueous solution and the mineral acid was as shown in Table 2.

  The holding time refers to the time from the completion of the addition of the mineral acid performed in the primary reaction step to the re-addition of the mineral acid in the secondary reaction step.

  In the secondary reaction step, the same mineral acid as in the primary reaction step was added over a predetermined time so that the reaction completion pH was reached. As shown in Table 2, the 10% concentration slurry viscosity of the finished raw material is a B-type viscometer obtained by subjecting the silica composite regenerated particle slurry that has undergone the reaction through the secondary reaction step to dehydration filtration and adjusting the solid content concentration to 10%. (Measurement temperature 25 ° C.).

[Measurement of regenerated particles and silica composite regenerated particles]
Tables 1 and 3 show the component analysis results of the regenerated particles and the silica composite regenerated particles. The inorganic constituents in each step were subjected to elemental analysis at an acceleration voltage (15 KV) using an X-ray microanalyzer manufactured by Horiba, Ltd., and converted into oxides from the constituents.

  The specific surface area and pore volume were measured using a mercury intrusion porosimeter (“PASCAL 140/240” manufactured by Terumo Corporation) after filtration of the sample and vacuum drying.

The amount of oil absorption is based on the kneading method described in JIS K 5101-13-2. That is, 2 g to 5 g of a sample dried at 105 ° C. to 110 ° C. for 2 hours is taken on a glass plate, and refined linseed oil (oxidized 4 or less) is dropped from the buret little by little to the center of the sample and kneaded with a spatula each time. The dripping and kneading operations are repeated, and the amount of refined linseed oil dripped is determined with the end point when the whole is first assembled into a single rod shape, and the oil absorption is calculated by the following equation.
Oil absorption amount = [linseed oil amount (ml) × 100] / sample (g)

  The particle size is measured when the particle size distribution is measured with a laser particle size distribution measuring device (laser analysis type particle size distribution measuring device “SALD-2200 type” manufactured by Shimadzu Corporation), and the cumulative volume with respect to the volume of all particles is 50%. It is determined as the particle diameter (d50). For the preparation of the measurement sample, silica composite regenerated particles were added to a 0.1% sodium hexametaphosphate aqueous solution and dispersed with an ultrasonic wave for 1 minute.

  An X-ray diffraction apparatus (Rigaku Denki, RAD2X) was used for the measurement of the hard substance. Measurement conditions: Cu-Kα-curved monochromator 40 KV-40 mA, diverging slit 1 mm SS 1 mm RS 0.3 mm, scanning speed 0.8 ° / min, scanning range 2 theta = 7 to 85 degrees, sampling 0.02 degrees.

  The productivity shown in Table 3 indicates that the yield of the silica composite reaction converted from the amount of unreacted chemical contained in the filtrate of the obtained silica composite regenerated particles is ◎, the yield is 95% or more, and 80% or more and less than 95%. 70% or more and less than 80% was evaluated as Δ, and less than 70% was evaluated as ×.

(Example 2)
A newspaper web for Example 2 was obtained in the same manner as Example 1 except that the silica composite regenerated particles had an average particle size of 1.5 μm (Production Example 8 shown in Table 3).

(Example 3)
A newspaper web for Example 3 was obtained in the same manner as Example 1 except that the average particle diameter of the silica composite regenerated particles was 1.7 μm (Production Example 4 shown in Table 3).

Example 4
A newspaper web for Example 4 was obtained in the same manner as Example 1 except that the average particle size of the silica composite regenerated particles was 5.5 μm (Production Example 1-2 shown in Table 3).

(Example 5)
A newspaper web for Example 5 was obtained in the same manner as Example 1 except that the silica composite regenerated particles had an average particle size of 12.5 μm (Production Example 1-3 shown in Table 3).

(Example 6)
A newspaper web for Example 6 was obtained in the same manner as Example 1 except that the average particle size of the cation-treated talc was 2 μm.

(Example 7)
A newspaper web for Example 7 was obtained in the same manner as Example 1 except that the average particle size of the cation-treated talc was 10 μm.

(Example 8)
A newspaper web for Example 8 was obtained in the same manner as Example 1 except that the average particle size of the cation-treated talc was 12 μm.

Example 9
A newspaper web for Example 9 was obtained in the same manner as Example 1 except that the amount of the silica composite regenerated particles added was 10 kg / pulpton.

(Example 10)
A newspaper web for Example 10 was obtained in the same manner as Example 1 except that the average particle size of white carbon was 15 μm.

(Example 11)
A newspaper web for Example 11 was obtained in the same manner as Example 1 except that the average particle size of white carbon was 24 μm.

(Example 12)
A newspaper web for Example 12 was obtained in the same manner as in Example 1 except that the amount of white carbon added was 5 kg / pulpton.

(Example 13)
A newspaper web for Example 13 was obtained in the same manner as in Example 1 except that the amount of the silica composite regenerated particles added was 5 kg / pulpton.

(Example 14)
A newspaper web for Example 14 was obtained in the same manner as Example 1 except that the amount of the silica composite regenerated particles added was 15 kg / pulpton.

(Example 15)
A newspaper web for Example 15 was obtained in the same manner as Example 1 except that the amount of the silica composite regenerated particles added was 50 kg / pulpton.

(Example 16)
Example 1 except that the amount of white carbon added is 10 kg / pulpton, the amount of silica composite regenerated particles added is 10 kg / pulpton, and the amount of cation-treated talc added is 10 kg / pulpton. The paper web for newspaper of Example 16 was obtained.

(Example 17)
Example 1 except that the amount of white carbon added is 25 kg / pulp ton, the amount of silica composite regenerated particles added is 25 kg / pulp ton, and the amount of cation-treated talc added is 25 kg / pulp ton. The paper web for newspaper of Example 17 was obtained.

(Example 18)
Example 1 except that the amount of white carbon added is 30 kg / pulpton, the amount of silica composite regenerated particles added is 40 kg / pulpton, and the amount of cation-treated talc added is 30 kg / pulpton. The paper web for newspaper of Example 18 was obtained.

(Example 19)
Example 1 except that the amount of white carbon added is 30 kg / pulp ton, the amount of silica composite regenerated particles added is 50 kg / pulp ton, and the amount of cation-treated talc added is 38 kg / pulp ton. The paper web for newspaper of Example 19 was obtained.

(Example 20)
A newspaper web for Example 20 was obtained in the same manner as Example 1 except that the J / W ratio was 1.030.

(Example 21)
A newspaper web for Example 21 was obtained in the same manner as Example 1 except that the J / W ratio was 1.025.

(Example 22)
A newspaper web for Example 22 was obtained in the same manner as Example 1 except that talc (average particle size 6 μm) that was not cation-treated was added instead of cation-treated talc (average particle size 6 μm).

(Example 23)
A newspaper web for Example 23 was obtained in the same manner as Example 1 except that the coating amount of the surface sizing agent was 0.2 g / m ² .

(Example 24)
A newspaper web for Example 24 was obtained in the same manner as Example 1 except that the coating amount of the surface sizing agent was 1.5 g / m ² .

(Example 25)
A newspaper web for Example 25 was obtained in the same manner as Example 1 except that the coating amount of the surface sizing agent was 2.0 g / m ² .

(Example 26)
A newspaper web for Example 26 was obtained in the same manner as Example 1 except that silica composite calcium carbonate (average particle diameter 8.5 μm) was added as silica-containing particles instead of silica composite regenerated particles.

(Comparative Example 1)
A newspaper web for Comparative Example 1 was obtained in the same manner as in Example 1 except that the cation-treated talc was not added.

(Comparative Example 2)
A newspaper web for Comparative Example 2 was obtained in the same manner as Example 1 except that the silica composite regenerated particles were not added.

(Comparative Example 3)
A newspaper web for Comparative Example 3 was obtained in the same manner as in Example 1 except that the J / W ratio was 0.998.

Each physical property of the obtained newspaper web was measured by the following method. These results are shown in Table 4.

(A) Basis weight It measured based on the "basis weight measuring method" as described in JISP8124.

(B) Ash content Measured according to “Paper, paperboard and pulp-ash content test method—525 ° C. combustion method” described in JIS P 8251.

(C) Whiteness Measured according to “Pulp—Diffusion Blue Light Reflectance (ISO Whiteness) Measurement Method” described in JIS P 8212.

(D) Blank paper opacity It was measured according to “Paper and paperboard—Opacity test method (paper backing)” described in JIS P 8149.

(E) Printing Opacity Offset web offset printing press (model: RI-2, manufactured by Ishikawajima Industrial Machinery Co., Ltd.), web offset web printing ink (trade name: News Zet Naturalis (black), Dainippon Ink & Chemicals, Inc. The ratio of the back-surface reflectance after printing to the back-surface reflectance before printing when the amount of ink is 9% and the printing surface reflectance is 9%.
(Back side reflectance after printing / Back side reflectance before printing) × 100 (%)
Asked. A spectral whiteness colorimeter (manufactured by Suga Test Instruments Co., Ltd.) was used for measuring the reflectance.

(F) Paper tearing speed In the “paperboard-paper peeling test method-accelerated printing method using an electric IGT tester” in accordance with JIS P 8129, the surface of the web for newspaper is accelerated from the winding edge of the web to the start of winding. And the printing speed when the fiber was completely broken was evaluated using an ink having a tack value of 18.

[Characteristic evaluation]
Next, the following characteristics were examined using the newspapers of Examples 1 to 26 and Comparative Examples 1 to 3. The results are shown in Table 4.

(G) Printing operability (peeling trouble)
Using a web offset press (model number: Metroliner, manufactured by Gos Graphic Systems Japan Co., Ltd.) equipped with a steel belt, printing was performed on 55 consecutive rolls (Volume A) of newsprint. The steel belt was examined for occurrence of peeling trouble and evaluated based on the following evaluation criteria.

(Evaluation criteria)
A: No paper breakage / peeling trouble occurred.
○: A peeling trouble occurred once or twice with 50 windings.
Δ: Peeling trouble occurred 3 times with 50 windings.
X: The peeling trouble occurred 4 times or more with 50 windings.

(H) Blanket paper dust piling Using an offset rotary printing press (model number: Metroliner, manufactured by Gossluffic Systems Japan), printing was performed on 55 continuous newspapers. The presence or absence of paper dust generation / deposition in the blanket non-image area was visually observed and evaluated based on the following evaluation criteria.
(Evaluation criteria)
(Double-circle): Generation | occurrence | production of paper dust is not recognized at all.
○: Slight generation of paper dust is observed, but no accumulation on the blanket is observed.
(Triangle | delta): Generation | occurrence | production of paper dust is recognized and it has accumulated on the blanket.
X: Accumulation of paper dust on the blanket is remarkable.

  Each of the newspaper webs of Examples 1 to 26 contains waste paper pulp as the pulp constituting the base paper, and contains talc, silica-containing particles, white carbon as fillers, and an ash content of 5% by mass or more and 15% by mass. % Or less. In the “paperboard-paper peeling test method-accelerated printing method using an electric IGT tester” in accordance with JIS P 8129, the aggregation of the pitch has not progressed. The fiber orientation is adjusted so that the paper breaking speed tested so as to accelerate to 343 cm / s or more, and the peeling trouble due to the pitch in the offset rotary press equipped with the steel belt is remarkably reduced. Moreover, it turns out that it has very high printing opacity by having the silica containing particle | grains and white carbon with high oil absorption.

  On the other hand, the newsprint of Comparative Example 1 does not contain talc, and the agglomeration of the pitch progresses, causing a peeling trouble due to the pitch. The newsprint paper of Comparative Example 3 is a paperboard-paper tear test method-accelerated printing method using an electric IGT test machine in accordance with JIS P 8129. Since the paper tearing speed tested to accelerate is less than 343 cm / s, it can be seen that a peeling trouble due to the pitch is likely to occur in an offset rotary press equipped with a steel belt. Since the newsprint of Comparative Example 2 does not contain silica-containing particles, printing opacity is low, and peeling trouble due to pitch is likely to occur.

  The newspaper web of the present invention has high printing opacity, and can be suitably used without a peeling trouble due to pitch in a cold offset rotary printing press equipped with a steel belt.

DESCRIPTION OF SYMBOLS 10 ... Raw material, 12 ... Storage tank, 14 ... 1st combustion furnace (internal heat kiln furnace), 20 ... Hot-air generating furnace, 22 ... Recombustion chamber, 26 ... Heat exchanger, 28 ... Induction fan, 30 ... Chimney, 31 ... External heat jacket, 32 ... second combustion furnace (external heat kiln furnace), 34 ... cooler, 36 ... particle size sorter, 42 ... heat treatment furnace (internal heat kiln furnace), 43 ... hot air generating furnace.
Y2 raw material

Claims (4)

  A newspaper web for cold offset printing using waste paper pulp as a main material, wherein the newspaper web has an ash content of 5% by mass to 15% by mass, and the newspaper web has at least white carbon and white carbon. In the “paperboard-paper peeling test method—accelerated printing method using an electric IGT tester” in accordance with JIS P 8129, the surface of the newspaper web is wound from the winding edge of the web. A newspaper web, wherein the fiber orientation is adjusted so that the paper breaking speed tested so as to accelerate in the starting direction is 343 cm / s or more.   The paper for newspaper according to claim 1, wherein the silica-containing particles are composite particles composed of regenerated particles mainly made of paper sludge and silica.   The newspaper wrapping paper according to claim 1 or 2, wherein the talc is a cation-treated talc whose surface is surface-treated with a cationizing agent. A surface sizing agent comprising starch and a styrenic polymer is coated on at least the surface of the web for newspaper, and the solid content coating amount of the surface sizing agent is 0.1 g / m ² or more to 1.0 g / m per side. The newspaper web according to any one of claims 1 to 3, wherein the newspaper web is ² or less.

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