JP2007092203A - Neutral newsprint paper for offset printing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain neutral newsprint paper for offset printing that has high ash yield in papermaking even in mixing of filler in a high ratio, has slight reduction in paper strength and stiffness regardless of high mixing ratio of filler and high bulkiness of paper, slight occurrence of breakage and edge dust during offset printing, excellent running nature, slight print through and excellent quality of the printing surface. <P>SOLUTION: The neutral newsprint paper for offset printing is obtained by adding a mixed slurry composed of inorganic particles having 0.1-30μm average particle diameter, a cationic compound and a starch glue liquid to paper stock, making base paper for newsprint paper having a filler ratio in paper of 5-40 solid content and coating the base paper with a surface treating agent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a neutral newspaper printing paper having a high filler yield at the time of papermaking, excellent in running properties with less paper breakage and paper dust trouble in offset printing, and having high opacity and excellent printing surface quality.

  In recent years, from the viewpoint of increasing awareness of environmental protection and reducing paper manufacturing costs, higher blending and bulking of fillers are progressing for the purpose of reducing the amount of pulp used. The same applies to newspaper printing paper. However, in the high-filler paper, the pulp content is reduced and the increase in the inhibition of the inter-fiber binding by the filler, and in the bulk paper, the inter-fiber binding of the pulp is weakened due to the lower density. The paper strength such as the tensile strength and interlayer strength of the paper and the stiffness such as bending stiffness and waist may be lowered, which may cause a problem in quality.

  In addition, the weight of newspaper printing paper, the speed of newspaper machines, double-sided dewatering, and high DIP blending, etc. overlap, and the yield of fillers during newspaper printing is very low.

  On the other hand, in terms of quality, it is most important to be able to withstand high-speed and large-scale printing, not to mention newspaper printing paper, and the demand for tensile strength related to paper break is extremely severe. In addition, since large-scale printing is performed in a short time, problems such as printing surface blur due to paper dust accumulation are also regarded as important. In recent years, in addition to the quality related to running performance, the demand for print quality has become stricter year by year due to the increase in color pages. In particular, the level of demand for the phenomenon in which characters and images printed during printing can be seen through from the opposite side, the so-called behind-the-scene, is increasing year by year.

  It is known that increasing the opacity and oil absorption of paper is the most effective way to reduce the penetration of newspaper printing paper. In order to increase the opacity, it is effective to mix titanium dioxide having a large specific scattering coefficient. However, titanium dioxide is expensive and it is not economical to mix a large amount. As a method for suppressing the slip-through of acidic newspaper printing paper, it is effective to blend a filler having a high oil absorption, and white carbon has been widely used.

  As a new technology related to recent newspaper printing paper, there is neutral papermaking of newspaper printing paper. Neutral newsprint containing 5-15% by weight of calcium carbonate as a filler for the purpose of providing neutral newsprint with strength, opacity, resin yield, and anti-offset printing plate wear resistance equivalent to or better than acid newsprint. And a manufacturing method thereof. However, no effective countermeasure is described for the reduction in paper strength due to the addition of calcium carbonate (see Patent Document 1).

  In addition, there is a trend toward high ash differentiation of newspaper printing paper. The present applicant has filed an application for newsprint for offset printing containing a filler (including calcium carbonate) as an ash content per paper weight at a content of 15 wt% or more and less than 40 wt%. However, there is no description of effective countermeasures regarding reduction in ash yield and reduction in paper strength due to filler addition (see Patent Document 2).

  Also, paper bulking agents have attracted attention as a technology for reducing the density of paper. Most of these bulking agents for paper are designed to reduce the density of the paper by interposing between the pulp fibers and inhibiting the interfiber bonding of the pulp. Although the use of paper can reduce the density of the paper, there is a problem in that the paper strength and rigidity are lowered.

  As a method of increasing the paper strength such as the tensile strength and interlayer strength of the newspaper printing paper and the rigidity such as bending stiffness and waist by the papermaking chemicals, a method of internally adding a paper strength enhancing agent such as polyacrylamide or starch is generally used. However, in order to obtain a sufficient paper strength and rigidity improvement effect, an addition amount more than usual is required, which tends to cause deterioration of the paper formation, and may reduce the paper strength and stiffness. In addition, it is considered that adding these chemicals having cohesiveness and adhesiveness to the papermaking process may cause unstable operation, and that adding chemicals is difficult from the viewpoint of cost.

  There is known a method for providing an effect obtained by adding and mixing chemicals to inorganic particles such as calcium carbonate, silica, titanium oxide, and clay. For example, a method of producing calcium carbonate that does not dissolve even in acidic papermaking by mixing fatty acid with calcium carbonate (see Patent Document 3), and calcium carbonate that does not dissolve in acidic papermaking by mixing oxalic acid or stearic acid with calcium carbonate. A method for producing (see Patent Document 4), a method for improving the sizing degree by mixing a cationic polymer as a sizing agent with calcium carbonate (see Patent Document 5), and 0.1% to 1% anionic property in an inorganic filler A method of improving sizing by mixing a substance and a cationic polymer that is a sizing agent of 0.1% to 10% (see Patent Document 6), and improving sizing by mixing fatty acid and starch in calcium carbonate A method (refer to Patent Document 7), a method for improving sizing by mixing a fatty acid with calcium carbonate or titanium oxide (refer to Patent Document 8), calcium carbonate A method of reducing the friction coefficient by mixing long chain aliphatic amines with pigments, silica, kaolin and the like (see Patent Document 9), and a method of improving sizing by mixing acrylonitrile copolymer with calcium carbonate ( Patent Document 10), and a method (see Patent Document 11) used as a drainage / retention aid by mixing polyvinylamine with calcium carbonate or bentonite. However, these methods are intended to stabilize calcium carbonate when acidic, improve size, and change the friction coefficient, and are not methods for improving paper strength and rigidity.

  On the other hand, as a technique for improving the paper strength by adding chemicals to inorganic particles, a method of mixing carboxymethyl cellulose or xanthan gum with calcium carbonate (see Patent Document 12), starch powder is mixed with inorganic particle slurry. Although a method of heating and gelling to make a composite (see Non-Patent Document 1) has been disclosed, it is still insufficient in terms of cost, effect, and practicality, and a more effective paper strength and stiffness improvement method is available. It has been demanded.

Japanese Patent No. 2889159 Japanese Patent Application No. 2003-083046 U.S. Patent No. 1839449 JP 59-228098 U.S. Pat.No. 5,147,507 Japanese National Patent Publication No. 10-505883 U.S. Pat.No. 5,541,212 Japanese National Patent Publication No. 08-507837 JP-T 09-504057 Special Table 2002-520504 Japanese Patent Laid-Open No. 08-188983 JP-T 09-5066397 Yulin Zhao et.al., Tappi Journal, 3,40 (2), 2005.

  As described above, even when a high amount of filler is blended, the yield of the filler during papermaking is high, and despite the high blending of filler and the bulk of the paper, there is little decrease in paper strength and stiffness, and there is no interruption during offset printing. There has been a demand for the development of neutral newsprint paper for offset printing that generates less paper and paper dust, has excellent runnability, and has high opacity and excellent printing surface quality.

  The problem to be solved by the present invention is that even if the filler is highly blended, the yield of the filler during papermaking is high, and despite the high blending of the filler and the bulk of the paper, there is little decrease in paper strength and stiffness, An object of the present invention is to provide a neutral newsprint for offset printing, which generates less paper and paper dust during offset printing, has excellent runnability, and has high opacity and excellent printing surface quality.

  A mixed slurry consisting of inorganic particles having an average particle size of 0.1 to 30 μm, a cationic compound, and starch paste is added to the paper, and a newsprint base paper having a paper content of 5 to 40% solids by weight is made. The surface treatment agent is applied to the base paper to obtain neutral newsprint for offset printing.

In general, an interaction such as hydrogen bonding does not work between the inorganic particles and the pulp fibers, and the inorganic particles interposed between the pulp fibers inhibit the hydrogen bonding between the pulp fibers. For this reason, the greater the amount of inorganic particles internally added to the paper, the lower the paper strength and stiffness. However, in the present invention, the following remarkable effects can be obtained by adding a mixed slurry composed of inorganic particles, a cationic compound, and starch paste into paper stock and making neutral newsprint for offset printing. It is done.
(1) By mixing inorganic particles, a cationic compound, and starch paste liquid, a composite in which these inorganic particles are used as a core and the surface thereof is coated with a complex of a cationic compound and starch can be obtained. When this paper is added internally, the filler is easily fixed to the pulp fiber by the action of the complex of the cationic compound and starch, so that the yield of the filler on the wire is improved.
(2) In addition, the amount of cationic compounds and starch in the paper increases, and inorganic particles coated with the complex of cationic compounds and starch can be bonded to pulp fibers, thereby increasing the blending of fillers. In addition, there is little decrease in paper strength and stiffness despite the increase in bulk of newsprint due to the internal use of a bulking agent for paper, for example. The neutral newsprint for offset printing containing inorganic particles coated with the complex of the cationic compound and starch of the present invention is a paper made by adding inorganic particles, a cationic compound and starch paste separately to pulp. However, paper strength and stiffness are remarkably improved.
(3) This paper strength improvement reduces the amount of paper breaks and paper dust generated during offset printing.
(4) It is possible to increase the filler content in the paper while suppressing the decrease in paper strength and rigidity by adding a high composite of inorganic particles as the core and the surface coated with a complex of a cationic compound and starch. Thus, the opacity is improved.

  In the present invention, a newsprint printing paper in which a mixed slurry comprising inorganic particles having an average particle size of 0.1 to 30 μm, a cationic compound, and a starch paste is added to the paper, and the filler content in the paper is 5 to 40% by solid weight A base paper is made, and a surface treatment agent is applied to the base paper to obtain a neutral newsprint for offset printing.

  Inorganic particles having an average particle size of 0.1 to 30 μm used in the present invention are clay, calcined kaolin, deramikaolin, titanium dioxide, zinc oxide, silicon oxide, amorphous silica, heavy calcium carbonate, light calcium carbonate, carbonic acid. There is no limitation as long as it is conventionally used as a filler for paper or a pigment for coated paper, such as magnesium, barium carbonate, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide, etc. Two or more types can be used in combination. Among these, heavy calcium carbonate and light calcium carbonate are preferable. That is, the neutral papermaking method is suitable as the papermaking method. When the inorganic particles are acidic particles, it is preferably adjusted to neutral to weakly alkaline by adding an alkaline liquid such as sodium hydroxide to the paper stock.

  The cationic compound used in the present invention includes cationized starch, polyamine epichlorohydrin, polyamide epichlorohydrin, polyvinylamine, a homopolymer of diallyldimethylammonium chloride, a copolymer of diallyldimethylammonium chloride and acrylamide, polyethyleneimine , Selected from the group of polyaluminum chloride and sulfuric acid band. These are used in the form of aqueous solutions or emulsions. These 1 type, or 2 or more types of mixed liquids can be used. The raw material of the cationized starch is not limited, and raw material starches such as corn, waxy maize, tapioca, sweet potato, potato, wheat and rice can be used. The cationic group may be a tertiary amine group or a quaternary ammonium group, and the degree of substitution (D.S.) is not limited.

  The starch paste used in the present invention is selected from the group of oxidized starch, urea-phosphorylated starch, hydroxyethylated starch, amphoteric starch, acetylated starch, and raw starch, and one or more of these are selected. A mixed paste can be used. The raw materials for these starches are not limited, and starches such as corn, waxy maize, tapioca, sweet potato, potato, wheat, rice, etc. can be used. Further, there is no limitation on the degree of substitution of these ether groups and ester groups.

In the present invention, an inorganic particle having an average particle size of 0.1 μm to 30 μm, a cationic compound, and a starch paste are mixed with stirring to prepare a mixed slurry. The order of addition of the inorganic particles, the cationic compound, and the starch paste at the time of mixing is not particularly limited, and for example, the following various addition orders can be employed.
(1) Add 1) the slurry of inorganic particles in the order of 2) an aqueous solution or emulsion of a cationic compound, and 3) starch paste.
(2) 1) Add to the slurry of inorganic particles in the order of 2) starch paste and 3) cationic compound.
(3) 1) Add to aqueous solution or emulsion of cationic compound in order of 2) slurry or powder of inorganic particles, 3) starch paste.
(4) Add 1) an aqueous solution or emulsion of a cationic compound in the following order: 2) starch paste, 3) slurry or powder of inorganic particles.
(5) Add 1) a slurry or powder of inorganic particles and 3) an aqueous solution or emulsion of a cationic compound to the starch paste solution in this order.
(6) To 1) the inorganic particle slurry, 2) an aqueous solution or emulsion of a cationic compound and a starch paste solution mixed in advance.
(7) Add 1) slurry or powder of inorganic particles in the order of 1) an aqueous solution or emulsion of a cationic compound and a starch paste solution.

  The mixing ratio of the inorganic particles, the cationic compound, and the starch paste is a solid weight ratio, and is in the range of inorganic particles / cationic compound / starch = 100 / 0.1 / 0.1 to 100/100/100, preferably 100 / 0.1 /0.1 to 100/50/100, more preferably 100 / 0.1 / 1 to 100/10/50. When the addition amount of the cationic compound and / or starch is less than 0.1% by weight, the effect of improving the yield of the filler is small, and further, the effect of improving the paper strength and the rigidity cannot be obtained. Since the effect reaches its peak, it is uneconomical.

  The apparatus for mixing the inorganic particles, the cationic compound, and the starch paste is not particularly limited as long as the apparatus can sufficiently stir and mix them. Mixing is between several minutes to several tens of minutes. The solid content concentration of the slurry at the time of mixing is not particularly limited, but is preferably 80% by weight or less, more preferably 70% by weight or less. The mixing temperature is preferably room temperature to 50 ° C.

  The mixed slurry of the inorganic particles, the cationic compound, and the starch paste solution may be temporarily stored and then added to the paper stock, or may be added continuously immediately after mixing. The addition place should just be a place where the filler is normally added, and it adds between a mixer and a head box.

  In paper machines, white water dehydrated in wire parts is being collected and reused in paper machines with the aim of saving water and heat energy. If present, the slime will propagate using this as a nutrient source, the slime layer adhering to the white water wall surface will fall off and be incorporated into the paper, resulting in paper defects such as foreign matter, and this may cause paper breaks during paper making May cause problems. In the present invention, since a large amount of starch is used for the treatment of inorganic particles, it is also considered that a problem of slime reproduction occurs. In order to avoid this, it is desirable to remove as much as possible the cationic compound and starch paste that are not firmly adsorbed on the inorganic particles, and the prepared mixed slurry comprising the inorganic particles, the cationic compound, and the starch paste may be filtered or filtered. The separated water can be separated by centrifugation, and the separated water can be drained out of the paper machine system, and the resulting dewatered cake can be redispersed in water, and then this dispersed slurry can be added to the paper stock.

  The content of the inorganic particles mixed with the cationic compound and starch in the paper is in the range of 5 to 40 solids by weight, preferably 5 to 30 solids by weight, more preferably 5 to 20 solids by weight, More preferred is 10-20% solids by weight. When the solid content is less than 5% by weight, the amount of inorganic particles that hinder hydrogen bonding between pulp fibers is small, so that paper having high paper strength and rigidity can be obtained without coating treatment as in the present invention. Therefore, even if the mixed slurry comprising the inorganic particles, the cationic compound, and the starch paste of the present invention is added as a filler, the effect of improving the paper strength and rigidity of the present invention is small. On the other hand, if it exceeds 40% by weight, the effects of improving the paper strength, rigidity and opacity of the present invention can be obtained, but there is a problem that papermaking itself becomes difficult.

  The inorganic particles treated with the cationic compound and starch paste are added to the paper stock and incorporated into the paper to obtain a newsprint base paper. The composition ratio of the inorganic particles present in the paper is: Cationic compound / starch = 100 / 0.05 / 0.05 to 100/90/90, and its presence can be easily confirmed by analyzing the composition of inorganic particles in the paper. As a method of separating the inorganic particle / cationic compound / starch composition from the paper, for example, the paper is disaggregated in a solvent that does not dissolve the cationic compound and starch, and then the pulp and the inorganic particles are separated by specific gravity. The method of separating based on the above can be mentioned. The inorganic particles separated from the paper by such a method adsorb cationic compounds and starch. By quantifying the amount of inorganic particles, cationic compounds, and starch in the separated inorganic particles, the inorganic particles / The composition ratio of the cationic compound / starch can be determined. The method for quantifying the inorganic particles, the cationic compound, or the starch may be any method that allows quantification with high accuracy, and a known quantification method may be employed.

  The raw material pulp used in the present invention is not particularly limited as long as it is a pulp usually used in newspaper printing paper, and is not limited to chemical pulp (CP), groundwood pulp (GP), chemiground pulp (CGP), refiner ground. Pulp (RGP), Thermomechanical pulp (TMP), Chemi-thermomechanical pulp (CTMP), Semi-chemical pulp (SCP), etc., and various softwood, hardwood pulp, bleached, unbleached pulp, Further, it is a pulp in which deinked pulp (DIP) or the like is appropriately blended according to the type of paper.

  If necessary, known internal sizing agents such as alkyl ketene dimer (AKD) sizing agents, alkenyl succinic anhydride (ASA) sizing agents, and neutral rosin sizing agents can be used.

  When making newspaper printing paper, various conventionally used nonionic and cationic retention agents, freeness improvers, paper strength improvers, and other internal paper additives are selected as needed. Used. Further, for example, sulfuric acid bands, aluminum chloride, sodium aluminate, basic aluminum compounds such as basic aluminum chloride and basic polyaluminum hydroxide, water-soluble aluminum compounds such as water-degradable alumina sol, sulfuric acid A polyvalent metal compound such as ferrous sulfate or ferric sulfate, silica sol, or the like may be internally added. Other starches for papermaking, various starches, polyacrylamide, urea resin, melamine resin, epoxy resin, polyamide resin, polyamide, polyamine resin, polyamine, polyethyleneimine, vegetable gum, polyvinyl alcohol, latex, polyethylene oxide, hydrophilic cross-linked polymer Various compounds such as particle dispersions and derivatives or modified products thereof can be used. Furthermore, internal additives for papermaking such as dyes, fluorescent brighteners, pH adjusters, antifoaming agents, pitch control agents, slime control agents and the like can be appropriately added depending on the intended use.

  In recent years, a technology for increasing the bulk (lowering density) of paper by adding a bulking agent for paper has been developed. Most of these bulking agents lower the paper strength and stiffness of paper. When the present invention is applied to bulky newspaper printing paper containing such a bulking agent and having reduced paper strength and stiffness, paper strength is increased. And the effect of giving rigidity is great.

  A bulky newspaper printing paper containing a bulking agent for paper will be described. The bulking agent is internally added to the stock. Specific examples of this bulking agent include oil-based nonionic surfactants, sugar alcohol-based nonionic surfactants, sugar-based nonionic surfactants, polyhydric alcohol-type nonionic surfactants, polyhydric alcohols and Fatty acid ester compound, higher alcohol or polyoxyalkylene adduct of higher fatty acid, polyoxyalkylene adduct of higher fatty acid ester, polyoxyalkylene adduct of polyhydric alcohol and fatty acid ester compound, fatty acid polyamidoamine, linear fatty acid Examples include monoamides and unsaturated fatty acid diamidoamines.

  This bulking agent is exemplified in the patent literature as follows. Paper bulking agent described in Japanese Patent No. 3128248, paper bulking agent described in Japanese Patent No. 3453505, paper bulking agent described in Japanese Patent No. 3482336, paper bulking agent described in Japanese Patent No. 3576962, Patent No. No. 3482337, a paper bulking agent described in Japanese Patent No. 2971447, a paper making paper quality improving agent described in Japanese Patent No. 3283248, a drying efficiency improving agent described in Japanese Patent No. 3338333, and a Japanese Patent No. 3387036. Smoothness and air permeability improver described in Japanese Patent No. 3517200, additive for papermaking described in Japanese Patent No. 3517200, paper quality improver described in Japanese Patent Laid-Open No. 2001-248100, and paper quality improvement described in Japanese Patent Laid-Open No. 2003-336196 Agent, paper quality improver described in JP 2004-52216 A, paper quality improver described in JP 2004-107865 A, paper quality improver described in JP 2004-91950 A, JP 2005-60921 A The powdery papermaking composition described in the above, the papermaking drug particles described in JP2005-68633, and the paper non-use paper described in JP2000-273792A. A clarifying agent, an additive for recycling used paper described in JP-A-2002-129497, an additive for recycling used paper described in JP-A-2002-275786, an additive for recycling used paper described in JP-A-2002-294586, A bulking agent described in JP-A-2002-294594, a bulking agent for paper described in JP-A-2003-96692, a bulking agent described in JP-A-2003-96693, and an additive for recycling used paper described in JP-A-2003-96694 Used paper recycling additive described in JP-A-2003-96695, paper thickness improving agent described in JP-A-2003-171897, bulking agent for paper described in JP-A-2003-247197, JP-A-2003-253588 Paper bulking agent described in JP-A-2003-253589, paper bulking agent described in JP-A-2003-253590, paper bulking agent disclosed in JP-A-2003-253590, paper density-increasing agent described in JP-A-2003-328297 Paper densifying agents described in JP-A-2003-313799, paper-making additives described in JP-A-2004-11058, paper-density reducing agents described in JP-A-2004-27401, JP-A 2004 -115935 for paper Agent, paper bulking agent described in JP-A-2004-76244, paper modifier described in JP-A-2004-176213, paper additive described in JP-A-2004-308095, JP-A-2005- No. 42278, a bulking agent described in JP-A-2005-42279, a bulking agent for papermaking described in JP-A-2005-60891, a paper softening agent described in Japanese Patent No. 3521422, JP-A-2002 -275792, bulky sizing agent described in JP 2002-275792, paper bulk sizing agent described in JP 2003-286692, paper manufacture described in JP 2004-270074 Bulking agent composition for paper, Bulking agent for papermaking described in JP-A-2004-285490, Bulking agent for paper described in JP-A-2004-339629, Bulking agent described in JP-A-2005-54330, JP-A-2005- A bulking agent described in Japanese Patent No. 68592.

  The bulking agent for paper referred to in the present invention is a general term for compounds having both a hydrophobic group and a hydrophilic group in a molecule, which can reduce the density of paper when paper is added internally to the stock. . In addition to the bulking agent as described in the above-mentioned patent document, the papermaking paper quality improver, drying efficiency improver, smoothness and air permeability improver, papermaking additive, paper quality improver, paper opacifier, waste paper recycling Additives, paper thickness improvers, paper densifying agents, paper modifiers, paper softening agents, bulky softening agents, papermaking bulky sizing agents, and the like.

  The bulking agent is usually added in the range of 0.2 to 20% by solid weight with respect to the raw material pulp. If the solid content is less than 0.2% by weight, the effect of reducing the density is small, and even if added in excess of 20% by solid weight, the bulky effect reaches its peak, so there is no meaning and the cost cannot be put into practical use.

  The bulking agent is preferably added after the raw material mixer and before the addition of the mixed slurry composed of the inorganic particles of the present invention, the cationic compound, and the starch paste, and other fillers.

When making newsprint paper with improved paper strength and stiffness according to the present invention, surface coating may be applied for the purpose of improving surface strength, imparting water resistance, and improving ink deposition. There are no particular restrictions on the type of surface treatment agent. For example, raw starch, modified starch such as oxidized starch, esterified starch, cationized starch, enzyme-modified starch, aldehyde-modified starch, and hydroxyethylated starch, carboxy Cellulose derivatives such as methylcellulose, hydroxyethylcellulose, methylcellulose, modified alcohols such as polyvinyl alcohol and carboxyl-modified polyvinyl alcohol, styrene butadiene copolymers, polyvinyl acetate, vinyl chloride-vinyl acetate copolymers, polyvinyl chloride, polyvinylidene chloride, Polyacrylic acid ester, polyacrylamide and the like can be used alone or in combination. Among them, it is preferable to apply hydroxyethylated starch which is excellent in surface strength improvement effect. Among hydroxyethylated starches, after hydroxyethylation reaction of starch, in a solid state with a moisture content of 5 to 17%, hydrogen chloride gas, More preferred is a dry low molecular weight hydroxyethylated starch which has been reduced in molecular weight by acid treatment with hydrochloric acid, sulfuric acid or the like, or oxidation treatment with ammonium persulfate, hydrogen peroxide, chlorine gas or the like. In addition to the above-mentioned agents, surface sizing agents such as styrene acrylic acid, styrene maleic acid, olefinic compounds, and cationic sizing agents can be applied to the surface treatment agent. When applying a surface treating agent, the coating amount per both surfaces is 0.05-2.0 g / m < ² > by solid content weight.

  The type of the paper machine for making the base paper is not particularly limited, and can be appropriately made with a long net paper machine, a twin wire machine, a Yankee paper machine, or the like. The press line pressure is used within the normal operating range. The calendar may be bypassed or processed within the normal operating range.

  The apparatus for applying the surface coating agent to the neutral newsprint base paper for offset printing is not particularly limited as long as it is a public one, and a gate roll size press is generally preferable in a newspaper paper machine.

The basis weight of the obtained neutral newsprint for offset printing may be in the range of 37 to 52 g / m ² , and may be a level having a smoothness, a coefficient of friction, etc. comparable to those of ordinary newsprint for offset printing.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. However, the present invention is not limited to these examples. In addition, all% in an example shows solid content weight%.

In the following examples and comparative examples, physical properties, paper Clark stiffness, and pure bending stiffness were measured by the following methods.
(1) Average particle diameter: After treating the average particle diameter of surface-treated calcium carbonate and untreated calcium carbonate with an ultrasonic disperser for 5 minutes, a laser scattering particle size measuring device Master Sizer 2000 (manufactured by MARVERN) was used. Measured.
(2) Zeta potential: Zeta potential of surface-treated calcium carbonate and untreated calcium carbonate,
Measurement was performed using ZETASIZER3000HAS (manufactured by MALVERN).
(3) Breaking length: Conforms to JIS P 8113
(4) Pure bending stiffness: The initial pure bending stiffness of handmade paper was measured using a pure bending stiffness measuring apparatus (manufactured by Suga Test Instruments Co., Ltd.). The pure bending stiffness is not a stiffness measurement method stipulated by JIS, but shows a measured value close to the feel when the paper is actually bent by hand.
(5) ISO whiteness: Conforms to JIS P8148
(6) ISO opacity: Conforms to JIS P8149
(7) Filler yield: The amount of filler in the paper was calculated from the basis weight and ash content of the paper, and was calculated from the ratio to the charged amount of filler.
(8) Starch yield: The amount of starch in paper was measured using Biosensor BF-2 (manufactured by KS Systems) and calculated from the ratio to the amount of starch charged.
(9) Amount of paper dust: Using a TOSHIBA offset rotary press, printing with black ink at a printing speed of 900 rpm, scraping the paper dust accumulated on the blanket after printing 60,000 copies, measuring its weight, and measuring 100 cm ² Expressed by weight per unit. The film thickness of the fountain solution was 0.9 μm.

[Example 1]
While stirring 100 g of a 20% solid slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles at room temperature, polyvinylamine (trade name: Catiofast, 2% as a cationic compound) (VFH, manufactured by BASF) Add 10 g of aqueous solution, and further add 100 g of unprocessed corn starch (manufactured by Nippon Food Processing Co., Ltd.) with a concentration of 2% as starch paste, and stir at room temperature for 10 minutes to obtain a mixed composition It was. To pulp slurry containing 10% NBKP as raw material pulp, 20% TMP and 70% NDIP, a sulfuric acid band was added to 0.8% per pulp weight, and the mixed composition was added as a filler to 15% by weight per paper weight.
(1) The slurry was weighed so that the basis weight of the sheet after paper making would be 44 g / m ² and paper was made with a 150 mesh wire (area 200 cm ² ) using a round TAPPI paper machine. Next, it was press-dehydrated with a press machine at 4.18 kgf / cm ² for 5 minutes and further at 4.18 kgf / cm ² for 2 minutes, and tension-dried at 110 ° C. for 2 hours to prepare a hand-made paper. The obtained handmade paper was conditioned at 23 ° C. and 50% humidity for 1 day. The results are shown in Table 1.
(2) With this formulation, a newspaper base paper for offset printing with a basis weight of 44 g / m ² was made using a test paper machine, and a dry low molecular weight hydroxy was produced at a coating speed of 1,200 m / min using a gate roll coater. Ethylated starch (trade name: ETHYLEX2025, manufactured by Staley) was applied to both sides. The coating amount was adjusted to 1.0 g / m ² on both sides. The amount of paper dust generated from this newsprint for offset printing was measured and shown in Table 1.

[Example 2]
While stirring 100 g of a 20% solid slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles at room temperature, polyvinylamine (trade name: Catiofast, 2% as a cationic compound) (VFH, manufactured by BASF) Add 10 g of aqueous solution, and then add 100 g of unprocessed potato starch (manufactured by Nippon Food Processing Co., Ltd.) with a concentration of 2% as starch paste, and stir at room temperature for 10 minutes to obtain a mixed composition It was. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 3]
While stirring 100 g of a 20% solid slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles at room temperature, polyvinylamine (trade name: Catiofast, 2% as a cationic compound) (VFH, manufactured by BASF) 10 g of aqueous solution was added, and then 100 g of urea phosphorylated starch (trade name: Splet # 250, manufactured by Nippon Food Processing Co., Ltd.) with a concentration of 2% was added as a starch paste solution and stirred at room temperature for 10 minutes. Thus, a mixed composition was obtained. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 4]
While stirring 100 g of a 20% solid slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles at room temperature, polyvinylamine (trade name: Catiofast, 2% as a cationic compound) VFH, manufactured by BASF) 10 g of aqueous solution was added, and further 100 g of amphoteric starch (trade name: CATO3210, manufactured by NSC Japan) was added as a starch paste, and the mixture was mixed at room temperature for 10 minutes. I got a thing. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 5]
While stirring 100g slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles with a solid content concentration of 20% at room temperature, polyamine epichlorohydrin with 2% concentration as a cationic compound (trade name) : AC7300, manufactured by Seiko PMC Co., Ltd.) Add 10 g of aqueous solution, and then add 100 g of non-processed corn starch (manufactured by Nippon Food Processing Co., Ltd.) with a concentration of 2% as starch paste, and stir at room temperature for 10 minutes to mix Got. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 6]
While stirring 100g slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles with a solid content concentration of 20% at room temperature, polyamine epichlorohydrin with 2% concentration as a cationic compound (trade name) : AC7300, manufactured by Seiko PMC) Add 10 g of aqueous solution, and add 100 g of amphoteric starch (trade name: CATO315, manufactured by NSC Japan) as a starch paste solution and stir at room temperature for 10 minutes. A mixed composition was obtained. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 7]
While stirring 100g slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles with a solid content concentration of 20% at room temperature, cationized starch with 2% concentration as a cationic compound (trade name: CATO304) , Nippon NSC Co., Ltd.) Obtained. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 8]
While stirring 100 g of a 20% solid slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles at room temperature, 2% cationized starch (trade name: CATO302) as a cationic compound , Nippon NSC Co., Ltd.) 10 g of paste solution is added, and then 100 g of starch starch solution (product name: SK-20, manufactured by Nippon Corn Starch Co., Ltd.) with a concentration of 2% is added as starch paste solution and stirred at room temperature for 10 minutes. A mixed composition was obtained. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 9]
2% cationized starch as a cationic compound (trade name: CATO304, manufactured by NSC Japan) 10g of starch paste, 2% oxidized starch as a starch paste (trade name: MS-3800, manufactured by Nippon Food Processing Co., Ltd.) ) 100 g of paste solution was added and stirred at room temperature for 10 minutes. This mixture was added as inorganic particles to 100 g of a slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) having a solid content concentration of 20% and stirred at room temperature for 10 minutes to obtain a mixed composition. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 10]
While stirring 100g slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles with a solid content concentration of 20% at room temperature, cationized starch with 2% concentration as a cationic compound (trade name: CATO304) (Manufactured by NSC, Japan) Add 10g of paste solution, and then add 100g of hydroxyethylated starch (trade name: ETHYLEX2025, manufactured by Stayley) as a starch paste solution and stir at room temperature for 10 minutes to mix A composition was obtained. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 11]
While stirring 100g slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles with a solid content concentration of 20% at room temperature, cationized starch with 2% concentration as a cationic compound (trade name: CATO304) (Manufactured by NSC, Japan) Add 10g of paste, and then add 100g of acetylated starch (trade name: Z-300, manufactured by Nissho Chemical Co.) with a concentration of 2% as starch paste and stir at room temperature for 10 minutes. Thus, a mixed composition was obtained. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 12]
While stirring 100g slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles with a solid content concentration of 20% at room temperature, polyamide epichlorohydrin with 2% concentration as a cationic compound (trade name) : WS4020, manufactured by Seiko PMC Co., Ltd.) Add 10 g of aqueous solution, and then add 100 g of raw corn starch (manufactured by Nippon Food Processing Co., Ltd.) with a concentration of 2% as starch paste, and stir at room temperature for 10 minutes to mix the composition. Got. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 13]
While stirring 100 g of a 20% solid slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles at room temperature, diallyldimethylammonium chloride having a concentration of 2% as a cationic compound (in Table 1) Add 10 g of aqueous solution of homopolymer (trade name: AC7304, manufactured by Seiko PMC), and add 100 g of 2% unprocessed corn starch (manufactured by Nippon Food Processing Co., Ltd.) as a starch paste. The mixture was stirred at room temperature for 10 minutes to obtain a mixed composition. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 14]
While stirring 100 g of a 20% solid slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles at room temperature, diallyldimethylammonium chloride having a concentration of 2% as a cationic compound (in Table 1) 10% aqueous solution of corn starch (product name: N7527, manufactured by OndeoNalco) and 100g of unprocessed corn starch (manufactured by Nippon Food Processing Co., Ltd.) with a concentration of 2%. The mixture was added and stirred at room temperature for 10 minutes to obtain a mixed composition. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 15]
While stirring 100g slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles with a solid content concentration of 20% at room temperature, polyethyleneimine (trade name: Catiofast) with a concentration of 2% as a cationic compound SF, manufactured by Seiko PMC Co., Ltd.) 10 g of aqueous solution was added. Obtained. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 16]
While stirring 100g slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles with a solid concentration of 20% at room temperature, polyaluminum chloride with 2% concentration as a cationic compound (trade name: PAC (Manufactured by Nippon Light Metal Co., Ltd.) 10 g of an aqueous solution was added. It was. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 17]
While stirring 100 g of a slurry of 20% solid concentration of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles at room temperature, 10 g of a 2% concentration sulfuric acid band aqueous solution was added as a cationic compound. Further, 100 g of raw corn starch (manufactured by Nippon Food Processing Co., Ltd.) with a concentration of 2% as starch paste was added and stirred at room temperature for 10 minutes to obtain a mixed composition. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 18]
While stirring 100 g of a 20% solid slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles at room temperature, polyvinylamine (trade name: Catiofast, 2% as a cationic compound) (VFH, manufactured by BASF) Add 10 g of aqueous solution, and further add 100 g of unprocessed corn starch (manufactured by Nippon Food Processing Co., Ltd.) with a concentration of 2% as starch paste, and stir at room temperature for 10 minutes to obtain a mixed composition It was. A pulp slurry containing 10% NBKP, 20% TMP, and 70% NDIP as raw material pulp, 0.8% sulfuric acid band per pulp weight, 1.0% paper bulking agent (trade name: KB-110, manufactured by Kao Corporation) per pulp weight, The mixed composition was added as a filler so as to be 15% by weight based on the paper weight. (1) The slurry was weighed so that the basis weight of the sheet after paper making would be 44 g / m ² and paper was made with a 150 mesh wire (area 200 cm ² ) using a round TAPPI paper machine. Next, it was press-dehydrated with a press machine at 4.18 kgf / cm ² for 5 minutes and further at 4.18 kgf / cm ² for 2 minutes, and tension-dried at 110 ° C. for 2 hours to prepare a hand-made paper. The obtained handmade paper was conditioned at 23 ° C. and 50% humidity for 1 day. The results are shown in Table 1.
(2) With this formulation, a newspaper base paper for offset printing with a basis weight of 44 g / m ² was made using a test paper machine, and a dry low molecular weight hydroxy was produced at a coating speed of 1,200 m / min using a gate roll coater. Ethylated starch (trade name: ETHYLEX2025, manufactured by Staley) was applied to both sides. The coating amount was adjusted to 1.0 g / m ² on both sides. The amount of paper dust generated from this newsprint for offset printing was measured and shown in Table 1.

[Example 19]
While stirring 100 g of a 20% solid slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles at room temperature, 2% cationized starch (trade name: CATO302) as a cationic compound , Nippon NSC Co., Ltd.) Obtained. A pulp slurry containing NBKP 10%, TMP 20%, and NDIP 70% as a raw material pulp, a sulfuric acid band 0.8% per pulp weight, a paper bulking agent (trade name: KB-110, manufactured by Kao Corporation) 1.0% per pulp weight, The mixed composition was added as a filler so as to be 15% by weight based on the paper weight.
(1) The slurry was weighed so that the basis weight of the sheet after paper making would be 44 g / m ² and paper was made with a 150 mesh wire (area 200 cm ² ) using a round TAPPI paper machine. Next, it was press-dehydrated with a press machine at 4.18 kgf / cm ² for 5 minutes and further at 4.18 kgf / cm ² for 2 minutes, and tension-dried at 110 ° C. for 2 hours to prepare a hand-made paper. The obtained handmade paper was conditioned at 23 ° C. and 50% humidity for 1 day. The results are shown in Table 1.
(2) With this formulation, a newspaper base paper for offset printing with a basis weight of 44 g / m ² was made using a test paper machine, and a dry low molecular weight hydroxy was produced at a coating speed of 1,200 m / min using a gate roll coater. Ethylated starch (trade name: ETHYLEX2025, manufactured by Staley) was applied to both sides. The coating amount was adjusted to 1.0 g / m ² on both sides. The amount of paper dust generated from this newsprint for offset printing was measured and shown in Table 1.

[Example 20]
While stirring 100 g of a 20% solid slurry of heavy calcium carbonate (trade name: Super # 2000, manufactured by Maruo Calcium Co., Ltd.) as inorganic particles at room temperature, 2% polyvinylamine (trade name) as a cationic compound : Catiofast VFH (manufactured by BASF) Add 10 g of aqueous solution, and then add 100 g of unprocessed corn starch (manufactured by Nippon Food Processing Co., Ltd.) with a concentration of 2% as starch paste, and mix for 10 minutes at room temperature. I got a thing. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 21]
While stirring 100 g of a 20% solid content slurry of talc (trade name: NTL, manufactured by Nippon Talc Co., Ltd.) as inorganic particles at room temperature, polyvinylamine (trade name: Catifast VFH; 10 g of an aqueous solution (BASF) was added, and 100 g of unprocessed corn starch (manufactured by Nippon Food Processing Co., Ltd.) with a concentration of 2% was added as a starch paste solution and stirred at room temperature for 10 minutes to obtain a mixed composition. To pulp slurry containing 10% NBKP as raw material pulp, 20% TMP and 70% NDIP, a sulfuric acid band was added to 0.8% per pulp weight, and the mixed composition was added as a filler to 15% by weight per paper weight. A sodium hydroxide aqueous solution was added to the stock to adjust the pH of the stock to 8.3.
(1) The slurry was weighed so that the basis weight of the sheet after paper making would be 44 g / m ² and paper was made with a 150 mesh wire (area 200 cm ² ) using a round TAPPI paper machine. Next, it was press-dehydrated with a press machine at 4.18 kgf / cm ² for 5 minutes and further at 4.18 kgf / cm ² for 2 minutes, and tension-dried at 110 ° C. for 2 hours to prepare a hand-made paper. The obtained handmade paper was conditioned at 23 ° C. and 50% humidity for 1 day. The results are shown in Table 1.
(2) With this formulation, a newspaper base paper for offset printing with a basis weight of 44 g / m ² was made using a test paper machine, and a dry low molecular weight hydroxy was produced at a coating speed of 1,200 m / min using a gate roll coater. Ethylated starch (trade name: ETHYLEX2025, manufactured by Staley) was applied to both sides. The coating amount was adjusted to 1.0 g / m ² on both sides. The amount of paper dust generated from this newsprint for offset printing was measured and shown in Table 1.

[Example 22]
While stirring 100 g of a 20% solid slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles at room temperature, polyvinylamine (trade name: Catiofast, 2% as a cationic compound) (VFH, manufactured by BASF) 25 g of aqueous solution was added, and 250 g of raw corn starch (manufactured by Nippon Food Processing Co., Ltd.) with a concentration of 2% as starch paste was added and stirred at room temperature for 10 minutes to obtain a mixed composition It was. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 23]
While stirring 100 g of a 20% solid slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles at room temperature, polyvinylamine (trade name: Catiofast, 2% as a cationic compound) (VFH, manufactured by BASF) 50 g of aqueous solution was added, and then 500 g of raw corn starch (manufactured by Nippon Food Processing Co., Ltd.) with a concentration of 2% as starch paste solution was added and stirred at room temperature for 10 minutes to obtain a mixed composition It was. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Example 24]
While stirring 100 g of a 20% solid slurry of light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as inorganic particles at room temperature, polyvinylamine (trade name: Catiofast, 2% as a cationic compound) (VFH, manufactured by BASF) Add 100 g of aqueous solution, and further add 1000 g of raw corn starch (manufactured by Nippon Food Processing Co., Ltd.) with a concentration of 2% as starch paste, and stir at room temperature for 10 minutes to obtain a mixed composition It was. The same procedure as in Example 1 was performed except that this mixed composition was used in place of the mixed composition of Example 1. The results are shown in Table 1.

[Comparative Example 1]
Pulp slurry containing 10% NBKP as raw material pulp, 20% TMP and 70% NDIP, sulfuric acid band 0.8% per pulp weight, and light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as filler 30 per paper weight It added so that it might become weight%. Furthermore, polyvinylamine (trade name: Cassiofast VFH, manufactured by BASF) is added to 1% by weight per filler weight, and raw corn starch (manufactured by Nippon Food Processing Co., Ltd.) paste liquid becomes 10% by weight per filler weight. Were added.
(1) The slurry was weighed so that the basis weight of the sheet after paper making would be 44 g / m ² and paper was made with a 150 mesh wire (area 200 cm ² ) using a round TAPPI paper machine. Next, it was press-dehydrated with a press machine at 4.18 kgf / cm ² for 5 minutes and further at 4.18 kgf / cm ² for 2 minutes, and tension-dried at 110 ° C. for 2 hours to prepare a hand-made paper. The obtained handmade paper was conditioned at 23 ° C. and 50% humidity for 1 day. The results are shown in Table 1.
(2) With this formulation, a newspaper base paper for offset printing with a basis weight of 44 g / m ² was made using a test paper machine, and a dry low molecular weight hydroxy was produced at a coating speed of 1,200 m / min using a gate roll coater. Ethylated starch (trade name: ETHYLEX2025, manufactured by Staley) was applied to both sides. The coating amount was adjusted to 1.0 g / m ² on both sides. The amount of paper dust generated from this newsprint for offset printing was measured and shown in Table 1.

[Comparative Example 2]
Pulp slurry containing 10% NBKP as raw material pulp, 20% TMP and 70% NDIP, sulfuric acid band 0.8% per pulp weight, and light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as filler 30 per paper weight It added so that it might become weight%. Furthermore, add 10g aqueous solution of polyamine epichlorohydrin (trade name: AC7300, manufactured by Seiko PMC) at a concentration of 2% to 1% by weight of filler, and paste raw corn starch (manufactured by Nippon Food Processing Co., Ltd.) It added so that it might become 10 weight% per filler weight.
(1) The slurry was weighed so that the basis weight of the sheet after paper making would be 44 g / m ² and paper was made with a 150 mesh wire (area 200 cm ² ) using a round TAPPI paper machine. Next, it was press-dehydrated with a press machine at 4.18 kgf / cm ² for 5 minutes and further at 4.18 kgf / cm ² for 2 minutes, and tension-dried at 110 ° C. for 2 hours to prepare a hand-made paper. The obtained handmade paper was conditioned at 23 ° C. and 50% humidity for 1 day. The results are shown in Table 1.
(2) With this formulation, a newspaper base paper for offset printing with a basis weight of 44 g / m ² was made using a test paper machine, and a dry low molecular weight hydroxy was produced at a coating speed of 1,200 m / min using a gate roll coater. Ethylated starch (trade name: ETHYLEX2025, manufactured by Staley) was applied to both sides. The coating amount was adjusted to 1.0 g / m ² on both sides. The amount of paper dust generated from this newsprint for offset printing was measured and shown in Table 1.

[Comparative Example 3]
Pulp slurry containing 10% NBKP as raw material pulp, 20% TMP and 70% NDIP, sulfuric acid band 0.8% per pulp weight, and light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) as filler 30 per paper weight It added so that it might become weight%. Furthermore, 10g of cationized starch (trade name: CATO304, manufactured by NSC Japan) with a concentration of 2% was added to 1% by weight of the filler weight, and raw corn starch (manufactured by Nippon Food Processing Co., Ltd.) paste solution was added. It added so that it might become 10 weight% per weight.
(1) The slurry was weighed so that the basis weight of the sheet after paper making would be 44 g / m ² and paper was made with a 150 mesh wire (area 200 cm ² ) using a round TAPPI paper machine. Next, it was press-dehydrated with a press machine at 4.18 kgf / cm ² for 5 minutes and further at 4.18 kgf / cm ² for 2 minutes, and tension-dried at 110 ° C. for 2 hours to prepare a hand-made paper. The obtained handmade paper was conditioned at 23 ° C. and 50% humidity for 1 day. The results are shown in Table 1.
(2) With this formulation, a newspaper base paper for offset printing with a basis weight of 44 g / m ² was made using a test paper machine, and a dry low molecular weight hydroxy was produced at a coating speed of 1,200 m / min using a gate roll coater. Ethylated starch (trade name: ETHYLEX2025, manufactured by Staley) was applied to both sides. The coating amount was adjusted to 1.0 g / m ² on both sides. The amount of paper dust generated from this newsprint for offset printing was measured and shown in Table 1.

[Comparative Example 4]
A pulp slurry containing 10% NBKP, 20% TMP, and 70% NDIP as raw material pulp, 0.8% sulfuric acid band per pulp weight, and 1.0% per pulp weight of bulking agent for paper (trade name: KB-110, manufactured by Kao Corporation) Then, light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) was added as a filler so as to be 30% by weight per paper weight. Furthermore, polyvinylamine (trade name: Cassiofast VFH, manufactured by BASF) is added to 1% by weight per filler weight, and raw corn starch (manufactured by Nippon Food Processing Co., Ltd.) paste liquid becomes 10% by weight per filler weight. Were added.
(1) The slurry was weighed so that the basis weight of the sheet after paper making would be 44 g / m ² and paper was made with a 150 mesh wire (area 200 cm ² ) using a round TAPPI paper machine. Next, it was press-dehydrated with a press machine at 4.18 kgf / cm ² for 5 minutes and further at 4.18 kgf / cm ² for 2 minutes, and tension-dried at 110 ° C. for 2 hours to prepare a hand-made paper. The obtained handmade paper was conditioned at 23 ° C. and 50% humidity for 1 day. The results are shown in Table 1.
(2) With this formulation, a newspaper base paper for offset printing with a basis weight of 44 g / m ² was made using a test paper machine, and a dry low molecular weight hydroxy was produced at a coating speed of 1,200 m / min using a gate roll coater. Ethylated starch (trade name: ETHYLEX2025, manufactured by Staley) was applied to both sides. The coating amount was adjusted to 1.0 g / m ² on both sides. The amount of paper dust generated from this newsprint for offset printing was measured and shown in Table 1.

[Comparative Example 5]
A pulp slurry containing 10% NBKP, 20% TMP, and 70% NDIP as raw material pulp, 0.8% sulfuric acid band per pulp weight, and 1.0% per pulp weight of bulking agent for paper (trade name: KB-110, manufactured by Kao Corporation) Then, light calcium carbonate (trade name: PCX, manufactured by Shiraishi Calcium Co., Ltd.) was added as a filler so as to be 30% by weight per paper weight. Furthermore, cationized starch (trade name: CATO302, manufactured by NSC Japan) paste liquid is added to 1% by weight of filler, and raw corn starch (manufactured by Nippon Food Processing Co., Ltd.) paste liquid is 10% by weight of filler. It added so that it might become.
(1) The slurry was weighed so that the basis weight of the sheet after paper making would be 44 g / m ² and paper was made with a 150 mesh wire (area 200 cm ² ) using a round TAPPI paper machine. Next, it was press-dehydrated with a press machine at 4.18 kgf / cm ² for 5 minutes and further at 4.18 kgf / cm ² for 2 minutes, and tension-dried at 110 ° C. for 2 hours to prepare a hand-made paper. The obtained handmade paper was conditioned at 23 ° C. and 50% humidity for 1 day. The results are shown in Table 1.
(2) With this formulation, a newspaper base paper for offset printing with a basis weight of 44 g / m ² was made using a test paper machine, and a dry low molecular weight hydroxy was produced at a coating speed of 1,200 m / min using a gate roll coater. Ethylated starch (trade name: ETHYLEX2025, manufactured by Staley) was applied to both sides. The coating amount was adjusted to 1.0 g / m ² on both sides. The amount of paper dust generated from this newsprint for offset printing was measured and shown in Table 1.

[Comparative Example 6]
Pulp slurry containing 10% NBKP as raw material pulp, 20% TMP, 70% NDIP, 0.8% sulfuric acid band per pulp weight, and heavy calcium carbonate (trade name: Super # 2000, manufactured by Maruo Calcium Co., Ltd.) as a filler It added so that it might become 30 weight% per weight. Furthermore, polyvinylamine (trade name: Cassiofast VFH, manufactured by BASF) is added to 1% by weight per filler weight, and raw corn starch (manufactured by Nippon Food Processing Co., Ltd.) paste liquid becomes 10% by weight per filler weight. Were added.
(1) The slurry was weighed so that the basis weight of the sheet after paper making would be 44 g / m ² and paper was made with a 150 mesh wire (area 200 cm ² ) using a round TAPPI paper machine. Next, it was press-dehydrated with a press machine at 4.18 kgf / cm ² for 5 minutes and further at 4.18 kgf / cm ² for 2 minutes, and tension-dried at 110 ° C. for 2 hours to prepare a hand-made paper. The obtained handmade paper was conditioned at 23 ° C. and 50% humidity for 1 day. The results are shown in Table 1.
(2) With this formulation, a newspaper base paper for offset printing with a basis weight of 44 g / m ² was made using a test paper machine, and a dry low molecular weight hydroxy was produced at a coating speed of 1,200 m / min using a gate roll coater. Ethylated starch (trade name: ETHYLEX2025, manufactured by Staley) was applied to both sides. The coating amount was adjusted to 1.0 g / m ² on both sides. The amount of paper dust generated from this newsprint for offset printing was measured and shown in Table 1.

[Comparative Example 7]
Pulp slurry containing 10% NBKP as raw material pulp, 20% TMP, 70% NDIP, sulfuric acid band 0.8% per pulp weight, and filler talc (trade name: NTL, manufactured by Nippon Talc Co., Ltd.) 30% by weight paper weight It added so that it might become. Furthermore, polyvinylamine (trade name: Cassiofast VFH, manufactured by BASF) is added to 1% by weight per filler weight, and raw corn starch (manufactured by Nippon Food Processing Co., Ltd.) paste liquid becomes 10% by weight per filler weight. Were added. A sodium hydroxide aqueous solution was added to the stock to adjust the pH of the stock to 8.3.
(1) The slurry was weighed so that the basis weight of the sheet after paper making would be 44 g / m ² and paper was made with a 150 mesh wire (area 200 cm ² ) using a round TAPPI paper machine. Next, it was press-dehydrated with a press machine at 4.18 kgf / cm ² for 5 minutes and further at 4.18 kgf / cm ² for 2 minutes, and tension-dried at 110 ° C. for 2 hours to prepare a hand-made paper. The obtained handmade paper was conditioned at 23 ° C. and 50% humidity for 1 day. The results are shown in Table 1.
(2) With this formulation, a newspaper base paper for offset printing with a basis weight of 44 g / m ² was made using a test paper machine, and a dry low molecular weight hydroxy was produced at a coating speed of 1,200 m / min using a gate roll coater. Ethylated starch (trade name: ETHYLEX2025, manufactured by Staley) was applied to both sides. The coating amount was adjusted to 1.0 g / m ² on both sides. The amount of paper dust generated from this newsprint for offset printing was measured and shown in Table 1.

Examples 1-8, 10-17 using a mixed slurry prepared by adding a cationic compound and starch paste to light calcium carbonate and mixing them, and previously mixing the cationic compound and starch paste, Example 9 using a mixed slurry prepared by mixing in addition to calcium was more powerful than Comparative Examples 1 to 3 in which light calcium carbonate, a cationic compound, and starch paste were separately added to the pulp. Length), stiffness, filler yield, and starch yield were significantly improved. Moreover, since the average particle diameter of the prepared mixed slurry did not become excessively large, almost no decrease in whiteness or opacity was observed. Furthermore, the amount of paper dust was greatly reduced. On the other hand, the same applies to a system in which a bulking agent for paper is blended, and Examples 18 to 19 using a mixed slurry prepared by adding a cationic compound and starch paste to light calcium carbonate and mixing them are light calcium carbonate. Compared with Comparative Examples 4 to 5 to which a cationic compound and starch paste were added, paper strength (breaking length), rigidity, filler yield, and starch yield were significantly improved. In addition, the amount of paper dust decreased significantly. Example 22 in which the amount of raw material corn starch, which is a cationic compound added to light calcium carbonate, which is an inorganic filler, is 2.5 times the amount of Example 1, and which is 5 times the amount of Example 1, It can be seen that the paper strength and filler yield were further improved in Example 24 in which the amount was 23 or 10 times that in Example 1. Furthermore, in the mixed slurry prepared by adding and mixing the cationic compound and starch paste to the inorganic filler, Example 20 using heavy calcium carbonate as the inorganic filler and Example 21 using talc are respectively applied to the pulp. Compared with Comparative Examples 6 and 7 in which the inorganic filler, the cationic compound, and the starch paste solution were separately added, the paper strength and rigidity, the filler yield, and the starch yield were greatly improved. In addition, the amount of paper dust decreased significantly.

Claims (7)

  A mixed slurry consisting of inorganic particles having an average particle size of 0.1 to 30 μm, a cationic compound, and starch paste is added to the paper, and the resulting paper is made into a paper with a filler content of 5 to 40 solids by weight%. Neutral newsprint for offset printing, characterized in that a surface treatment agent is applied to a newsprint base paper.   The cationic compound is cationized starch, polyamine epichlorohydrin, polyamide epichlorohydrin, polyvinylamine, a homopolymer of diallyldimethylammonium chloride, a copolymer of diallyldimethylammonium chloride and acrylamide, polyethyleneimine, polyaluminum chloride, The neutral newsprint for offset printing according to claim 1, wherein the neutral newsprint is at least one selected from the group consisting of a sulfate band and a crosslinked cationized starch.   The starch paste mixed with inorganic particles is at least one paste selected from the group consisting of oxidized starch, urea-phosphorylated starch, hydroxyethylated starch, amphoteric starch, acetylated starch, and raw starch. The neutral newsprint for offset printing according to claim 1 or 2.   The inorganic particles are clay, calcined kaolin, deramikaolin, titanium dioxide, zinc oxide, silicon oxide, amorphous silica, heavy calcium carbonate, light calcium carbonate, magnesium carbonate, barium carbonate, aluminum hydroxide, calcium hydroxide, The neutral newsprint for offset printing according to any one of claims 1 to 3, wherein the neutral newsprint is at least one selected from the group consisting of magnesium hydroxide and zinc hydroxide.   The mixing ratio of the inorganic particles, the cationic compound, and the starch paste is inorganic particles / cationic compound / starch = 100 / 0.1 / 0.1 to 100/100/100 in terms of solid content weight ratio. The neutral newsprint paper for offset printing of any one of -4.   6. An inorganic particle composition having a composition ratio of inorganic particles / cationic compound / starch = 100 / 0.05 / 0.05 to 100/90/90 in solid weight is present in paper. Item 12. Neutral newsprint for offset printing according to any one of Items. The neutral newsprint paper for offset printing according to any one of claims 1 to 6, wherein a bulking agent for paper is internally added to the stock and contained in the paper.