JP4854341B2 - Coated paper for printing - Google Patents

Description

  The present invention relates to a coated paper for printing which is free from troubles of paper dust and blisters (interlayer delamination) in printing with an offset printing machine, has excellent printing running properties, and has excellent printing surface quality.

The most important quality of the coated printing paper used in the offset printing machine is that it can withstand the use in the offset printing machine, and the requirements for the interlaminar strength and the surface strength related to troubles with blisters and paper dust are extremely severe. In addition, the strength of paper tends to decrease due to the recent increase in fillers and increased blending of waste paper pulp.
In order to improve the printing surface of the coated paper for printing, it is effective to raise the ash content in the paper. The increase in the ash content in the paper produces uniformity in the coating layer by improving the smoothness of the base paper. However, in coated printing paper, if the ash content in the base paper is increased, high ash differentiation will cause in the offset press. There is a problem that blister troubles increase in a heatset type offset rotary press that dries ink by drying due to heat due to an increase in paper dust accumulated on the blanket or a decrease in interlayer strength.

  As a technique for keeping a large amount of filler in the paper and suppressing a decrease in paper strength, there is the following technique for pre-aggregating the filler and adding the aggregate to the paper. For example, it is possible to efficiently increase the specific scattering coefficient using an inexpensive general white pigment with a fine particle size, and to provide a method for producing paper with good yield on the paper layer and less reduction in paper strength and stiffness. As a problem, paper production is characterized in that the basic particles of a pigment having a refractive index of 1.45 to 1.65 are aggregated to form a large number of internal voids, and the aggregated particles of the pigment are added to a pulp slurry to make a paper. Examples of the pigment include calcium carbonate, kaolin, anhydrous calcium sulfate, gypsum, calcium sulfite, calcium silicate, barium sulfate, talc, and diatomaceous earth. Examples of the aggregation method include pH adjustment with acid and base, aluminum sulfate, and the like. The addition of inorganic flocculants and organic polymer flocculants is shown.

  However, this technique adjusts so as to form a large number of internal voids having a pore diameter of 0.1 μm or more and a size as close as possible to 0.1 μm, and this adjustment is difficult (see Patent Document 1). Next, it is an object to provide a paper product with a filler and a method for producing the same, which uses inexpensive calcium carbonate, improves opacity efficiently, has a good yield on the paper layer, and has little decrease in paper strength and stiffness. , A paper product mainly composed of pulp and calcium carbonate, agglomerated the particles having a calcium carbonate particle diameter of 0.1 to 0.3 μm and containing the aggregated particles in an amount of 5 to 80% by weight based on the dry pulp, and a method for producing the same As an aggregating method, pH adjustment with an acid or base, addition of an inorganic aggregating agent such as aluminum sulfate, and an organic polymer aggregating agent are shown. However, this technique requires dehydration drying in order to stabilize the aggregated particle size, and is not practical (see Patent Document 2).

  An object of the present invention is to provide a papermaking method that significantly improves wire wear of a paper machine that occurs when heavy calcium carbonate is used as a papermaking filler. Has been disclosed in which a papermaking method is previously added to a paper stock after being mixed with a cationically modified starch aqueous solution (see Patent Document 3). In the method of producing paper mainly composed of pulp and calcium carbonate filler, the filler is agglomerated using cationized starch and cationized guar gum as aggregating agent, or an inorganic aggregating agent such as aluminum sulfate or polyaluminum chloride is used. Then, after the filler is agglomerated, it is further agglomerated using cationized starch and cationized guar gum, and a method for producing a filler-added paper is disclosed in which the aggregated particles are added in an amount of 1 to 50% by weight in the paper. However, since a single ionic agent is used, the charge balance of the treatment system is determined only by the amount of the treatment agent, and the range of the optimum conditions for treatment becomes narrow in terms of charge balance. There is a problem that the adsorption efficiency to the filler becomes worse (see Patent Document 4).

In addition, a paper manufacturing method is disclosed in which a pre-aggregation filler is added to a finished paper material (particularly a finished paper material for newsprint paper) containing 30% or more of low grade pulp such as groundwood pulp and recycled pulp. Examples of fillers include clay, china clay, lithopone, sulfate filler, titanium pigment, titanium dioxide, satin white, talc, calcium carbonate, barium sulfate, gypsum, chalk, and the like. Examples thereof include gum, aluminum sulfate, mannogalactan, anionic starch derivatives, and cationic starch derivatives. However, there is no description of means for sufficiently satisfying the strength of paper and effective means for reducing the surface strength due to filler aggregation (see Patent Document 5).
Also, chemicals such as starch strength enhancers such as starch and polyacrylamide (hereinafter abbreviated as PAM) are used to suppress the decrease in paper strength due to the increase in filler. However, it is necessary to increase the amount of chemicals added, which causes problems such as contamination.

JP 54-50605 Japanese Patent Laid-Open No. 54-116405 JP-A-60-119299 Japanese Patent Laid-Open No. 10-60794 Japanese Unexamined Patent Publication No. 2000-129589

  The problem to be solved by the present invention is to provide a coated paper for printing which is excellent in print quality because it generates less blisters and paper dust during offset printing and has high smoothness.

Average obtained by treating the filler with a composite acrylamide copolymer comprising (A) an anionic polysaccharide and (B) a cationic and / or amphoteric acrylamide copolymer. A coated paper for printing is obtained by providing a coating layer mainly composed of a pigment and an adhesive on a base paper containing a pre-aggregated filler having a particle size of 10 to 80 μm as a ash content in the paper of 3 to 40 solids by weight. be able to.
It is preferable that the weight ratio of the component (A) and the component (B) in the composite acrylamide copolymer is A / B = 2/98 to 45/55. It is preferable that the addition amount of the composite acrylamide-type copolymer which consists of a component (A) and a component (B) is 0.1-3.0 solid content weight% with respect to a filler. The density of the coated paper is preferably 0.4 to 1.3 g / cm ³ .

  Laser diffraction method obtained by treating a filler with a composite acrylamide copolymer comprising (A) an anionic polysaccharide and (B) a cationic and / or amphoteric acrylamide copolymer A pre-aggregation filler having an average particle diameter of 10 to 80 μm is added, and a coating layer containing a pigment and an adhesive is provided on a base paper containing 3 to 40% by weight of ash in the paper. When printing is performed using an offset printing machine using a coated paper for printing, it is possible to provide a coated paper for printing with less blistering or paper dust during printing, higher smoothness and good print quality.

  The pulp raw material of the coated paper for printing produced in the present invention is not particularly limited, and it is hardwood kraft pulp (LKP), softwood kraft pulp (NKP), deinked pulp (DIP), ground pulp (GP ), Thermomechanical pulp (TMP), chemithermomechanical pulp (CTMP), etc., as long as they are generally used as a papermaking raw material for coated printing paper.

As a result of studying the combination of a filler and a flocculant, the inventors of the present invention have (A) an anionic polysaccharide and (B) a cationic and / or amphoteric acrylamide copolymer. We have found that a complex acrylamide copolymer is optimal.
The reason why the composite acrylamide copolymer is most suitable is that the composite PAM is composed of (A) an anionic polysaccharide having different characteristics in terms of ionicity and polymer structure, and (B) a cationic or amphoteric PAM. In order to form a polyion complex having both characteristics due to the anionic and high molecular weight spreading structure of the polysaccharide and the cationic and hydrophilic characteristics of PAM, a moderate aggregation effect on filler particles such as calcium carbonate and It is considered that this is because the high affinity to the pulp slurry can be exhibited. Further, since the filler is aggregated in advance by adding the pre-aggregated filler to the paper, it is hardly affected by the anionic substance in the paper, and the yield of the filler is greatly improved.

In addition, when adding internal additives such as cationized starch and PAM paper strength enhancer to pulp slurry containing filler treated with composite PAM, it is synergistic without inhibiting the effects of filler and chemical. Therefore, a large paper strength improvement effect can be obtained with a smaller amount of chemicals.
That is, a coated filler obtained by treating a filler such as calcium carbonate with a composite PAM in which two specific components having different charge characteristics are combined has an appropriate agglomeration effect, and has an excellent affinity with the pulp slurry. Since the compatibility with the internally added chemicals is good, it is possible to exert a large paper strength enhancing effect with a small amount of chemicals even in highly filled paper.

The pre-agglomerated filler is preferably produced by adding a composite PAM solution prepared in advance using the component (A) and the component (B) to the filler slurry, but the two components of the component (A) and the component (B). Can be added separately to the filler slurry.
As the filler for pre-aggregation, known ones can be optionally used. For example, light calcium carbonate, heavy calcium carbonate, clay, calcined clay, diatomaceous earth, talc, kaolin, calcined kaolin, deramikaolin, magnesium carbonate, barium carbonate. , Titanium dioxide, zinc oxide, silicon oxide, amorphous silica, aluminum hydroxide, calcium hydroxide, magnesium hydroxide, zinc hydroxide and other inorganic fillers, urea-formalin resin, polystyrene resin, phenol resin, or micro hollow particles Can be used, preferably calcium carbonate, more preferably light calcium carbonate.

  Furthermore, the shape of the light calcium carbonate is preferably a rosetta type, a spindle type or a columnar type. The average particle size of the filler is preferably from 0.1 to 20 μm, and the specific surface area is preferably from 3 to 20 m 2. The average particle size of the pre-agglomerated filler particularly affects the strength of the paper and the amount of paper dust. A suitable average particle diameter is 10 to 80 μm. When the degree of aggregation is weak and the average particle diameter is less than 10 μm, the strength of the paper is low. Conversely, when the degree of aggregation is strong and the average particle diameter exceeds 80 μm, the paper strength is not a problem, but the whiteness decreases. Or the amount of paper dust increases.

The complex PAM of the present invention comprises (A) an anionic polysaccharide and (B) a cationic and / or amphoteric PAM. In this case, anionic PAM is excluded from component (B).
As the anionic polysaccharide (A), derivatives such as starches, alginic acids, celluloses, and gums into which carboxyl groups, sulfate groups, or sulfonate groups are introduced can be used singly or in combination as acid substituents. .
As a specific method for producing an anionic polysaccharide, a polysaccharide having a carboxyl group can be produced by allowing an anionic agent such as chloroacetic acid to act on various polysaccharides. Commercially available anionic polysaccharides include carboxymethyl celluloses (carboxymethyl cellulose and salts thereof; hereinafter referred to as CMC), alginic acids (alginic acid and salts thereof), xanthan gum, carboxymethyl guar gum, phosphorylated guar gum, carboxymethyl starch or phosphorus Examples include acid starch. In the present invention, the anionic polysaccharide is preferably CMC or alginic acid.

Among the components (B), the amphoteric acrylamide copolymer (referred to as amphoteric PAM for convenience) is composed of (a) (meth) acrylamide, (b) a cationic monomer, and (c) an anionic monomer as constituent components. To do.
Examples of the (meth) acrylamide (a) include acrylamide (abbreviated as AM) and / or methacrylamide.
The cationic monomer (b) comprises a primary to tertiary amino group-containing (meth) acrylamide, a primary to tertiary amino group-containing (meth) acrylate, a quaternary ammonium base-containing (meth) acrylamide, and a quaternary ammonium base (meta). ) Acrylate, diallyldialkylammonium halide and the like, and one or more cationic groups in the molecule. For example, in a quaternary ammonium base-containing monomer, the compound represented by the following general formula (1) is This is a representative example.

[CH ₂ = C (R ₁ ) −CO−A−R ₂ −N ⁺ (R ₃ ) (R ₄ ) (R ₅ )] X ⁻ (1)
(In the formula (1), R ₁ is H or CH _3; R ₂ is C ₁ -C ₃ alkylene _{group; R 3, R 4, R} 5 is H, C ₁ -C ₃ alkyl group, a benzyl group, CH ₂ CH (OH) CH ₂ N ⁺ (CH ₃ ) ₃ X ⁻ , which may be the same or different; A is O or NH; X is an anion such as halogen or alkyl sulfate)

As this cationic monomer (b), primary to tertiary amino group-containing (meth) acrylamide, primary to tertiary amino group-containing (meth) acrylate, quaternary ammonium base-containing (meth) acrylamide, quaternary ammonium base-containing ( (Meth) acrylate is preferred.
The primary or secondary amino group-containing (meth) acrylamide is a primary amino group-containing (meth) acrylamide such as aminoethyl (meth) acrylamide, or methylaminoethyl (meth) acrylamide, ethylaminoethyl (meth) acrylamide or Secondary amino group-containing (meth) acrylamides such as t-butylaminoethyl (meth) acrylamide. The tertiary amino group-containing (meth) acrylamide is dimethylaminoethyl (meth) acrylamide, dimethylaminopropyl (meth) acrylamide (dimethylaminopropyl acrylamide is abbreviated as DMAPAA), diethylaminoethyl (meth) acrylamide or diethylaminopropyl ( A representative example is dialkylaminoalkyl (meth) acrylamide such as (meth) acrylamide.

The primary or secondary amino group-containing (meth) acrylate is a primary amino group-containing (meth) acrylate such as aminoethyl (meth) acrylate, methylaminoethyl (meth) acrylate, ethylaminoethyl (meth) acrylate, or t- Secondary amino group-containing (meth) acrylates such as butylaminoethyl (meth) acrylate. The tertiary amino group-containing (meth) acrylate is dimethylaminoethyl (meth) acrylate (dimethylaminoethyl methacrylate is abbreviated as DM), dimethylaminopropyl (meth) acrylate, diethylaminoethyl (meth) acrylate or diethylaminopropyl ( A representative example is a dialkylaminoalkyl (meth) acrylate such as (meth) acrylate.
The quaternary ammonium base-containing (meth) acrylamide or quaternary ammonium base-containing (meth) acrylate is obtained by converting tertiary ammonium base-containing (meth) acrylamide or tertiary ammonium base-containing (meth) acrylate to methyl chloride, benzyl chloride, sulfuric acid. Mono-quaternary base-containing monomers using quaternizing agents such as methyl and epichlorohydrin, such as acrylamidopropylbenzyldimethylammonium chloride, methacryloyloxyethyldimethylbenzilammonium chloride (DMBQ), acryloyloxyethyldimethylbenzyl Ammonium chloride, (meth) acryloylaminoethyltrimethylammonium chloride, (meth) acryloylaminoethyltriethylammonium chloride, (meth) acryloyloxyethyl trime Examples include tylammonium chloride and (meth) acryloyloxyethyl triethylammonium chloride.

As the cationic monomer, a bis-quaternary base-containing monomer having two quaternary ammonium bases in the molecule can be used from the viewpoint of increasing the molecular weight. Specific examples include bis-quaternary base-containing (meth) acrylamide having two quaternary ammonium bases, or bis-quaternary base-containing (meth) acrylate. Examples of bis quaternary base-containing (meth) acrylamide include bis quaternary base-containing (meth) acrylamide (DMAPAA-Q2) obtained by reacting dimethylaminopropylacrylamide with 1-chloro-2hydroxypropyltrimethylammonium chloride. (Abbreviated). This DMAPAA-Q2 is represented by the following general formula (1) of the cationic monomer: R ₁ = H, R _{2 =} propylene group, A = NH, R ₃ and R ₄ are each methyl group, R ₅ = CH ₂ CH ( OH) CH ₂ N ⁺ (CH ₃ ) ₃ C ⁻ , X = a compound corresponding to chlorine.

On the other hand, the diallyldialkylammonium halide belonging to the quaternary ammonium base-containing cationic monomer is, for example, diallyldimethylammonium chloride.
The anionic monomer (c) which is a structural unit of the amphoteric PAM is an α, β-unsaturated carboxylic acid or an α, β-unsaturated sulfonic acid.
The unsaturated carboxylic acids are (meth) acrylic acid (acrylic acid is abbreviated as AA), (anhydrous) maleic acid, fumaric acid, itaconic acid (abbreviated as IA), (anhydrous) citraconic acid, its sodium, potassium and ammonium salts Etc.
Examples of the unsaturated sulfonic acids include vinyl sulfonic acid, (meth) allyl sulfonic acid, styrene sulfonic acid, sulfopropyl (meth) acrylate, 2- (meth) acrylamide-2-methylpropane sulfonic acid, and salts thereof.

In amphoteric PAM, the above components (a) to (c) are further used with a crosslinkable monomer (d) and / or a chain transfer agent (e) to give the copolymer a branched crosslink structure. Can do.
The cross-linking monomer (d) contributes to increase the molecular weight of the copolymer and increase the active site for yielding ash, and bis (methylene bisacrylamide (abbreviated as MBAM), ethylene bis (meth) acrylamide, etc. Di (meth) acrylates such as (meth) acrylamides, ethylene glycol di (meth) acrylate and diethylene glycol di (meth) acrylate, dimethylacrylamide (abbreviated as DMAM), methacrylonitrile, and the like can be used.

The chain transfer agent suppresses the increase in the viscosity of the copolymer, acts to adjust the molecular weight by increasing the branched structure, isopropyl alcohol (abbreviated as IPA), sodium methallylsulfonate (abbreviated as SMS), allyl Known chain transfer agents such as sodium sulfonate (abbreviated as SAS), mercaptans such as n-dodecyl mercaptan, mercaptoethanol or thioglycolic acid can be used.
Further, in the amphoteric PAM, if necessary, nonionic monomers such as acrylonitrile may be used as other monomers.

The components (a) to (c) of amphoteric PAM (A) can be used alone or in combination.
The content of the components (a) to (c) in the amphoteric PAM (A) is arbitrary and is not particularly limited, but the content of (meth) acrylamide (a) relative to the copolymer is 65 to 98.8 mol%. The cationic monomer (b) is preferably 1 to 20 mol%, and the anionic monomer (c) is preferably 0.2 to 15 mol%.
On the other hand, the cationic acrylamide copolymer (referred to as cationic PAM for convenience) among the components (B) comprises (meth) acrylamide (a) and a cationic monomer (b) as constituent components.
Needless to say, these (meth) acrylamide (a) and the cationic monomer (b) can use the corresponding components listed as constituent monomer components of the amphoteric PAM.

Also in the cationic PAM, the above components (a) and (b) are further branched to the copolymer using the crosslinkable monomer (d) and / or the chain transfer agent (e). You may make it give a structure. Furthermore, in this cationic PAM, if necessary, a nonionic monomer such as acrylonitrile may be used as another monomer.
Further, the components (a) and (b) of the cationic PAM can be used alone or in combination, respectively, as in the case of the amphoteric PAM.

The contents of the components (a) and (b) in the cationic PAM are arbitrary and are not particularly limited. However, the content of (meth) acrylamide in the copolymer is 85 to 99 mol%, the cationic monomer ( b) is preferably 1 to 15 mol%.
The composite PAM is prepared by mixing components (A) and (B), or is produced by polymerizing the constituent monomer of component (B) in the presence of component (A).
The combinations of the components in the above mixing method are as follows (1) to (3).
(1) Anionic polysaccharide and amphoteric PAM
(2) Anionic polysaccharide and cationic PAM
(3) Anionic polysaccharide, amphoteric PAM and cationic PAM

By mixing the component (A) and the component (B), a polyion complex having both the anionic and high molecular weight spreading structure of the polysaccharide and the cationic and hydrophilic characteristics of the acrylamide copolymer is obtained. It is formed.
On the other hand, when the component (B) is produced by copolymerizing the constituent monomers as in the above polymerization method, the composite PAM can be produced by coexisting the component (A).
That is, the constituent monomers for producing amphoteric or cationic PAM are (a) acrylamide, (b) cationic monomers, and (c) anionic monomers as described above. When a copolymerization reaction is carried out in the presence of saccharide, an anionic polysaccharide is mixed in the generated amphoteric or cationic PAM, and both form a polyion complex.
In other words, when the composite PAM of the present invention is produced by copolymerizing a cationic or amphoteric PAM, the anionic polysaccharide (A) may be added before the copolymerization reaction, It may be added later, and a polyion complex may be formed between components (A) and (B).

In producing the composite PAM of the present invention, the mixing ratio (weight ratio) of the component (A) and the component (B) is preferably A / B = 2/98 to 45/55, and 4/96 to 30/70. Is more preferable.
If the anionic polysaccharide (A) is more than 45% by weight, the anion becomes excessive, the adsorption rate to the filler decreases, the particle system of the coated filler does not increase properly, and the yield may decrease. is there.
Since two types of composites having different charge characteristics are a feature of the present invention, the effect of the composite is reduced when the anionic polysaccharide (A) is less than 2% by weight.

The amount of the processing agent is 0.1 to 3.0% by weight based on the filler to be agglomerated so that the particle size of the agglomerated filler can be easily adjusted to 10 to 80 μm. It is hard to break and easy to maintain its shape. When the amount of the flocculant is 0.1% by weight or less of the filler, the average particle diameter of the flocculant filler tends to be smaller than 10 μm, and the paper strength improvement effect cannot be obtained.
On the other hand, even if 3.0% by weight or more is added, no further improvement in paper strength can be obtained, and only the cost of using the chemicals is increased, which is not practical.
The preliminary agglomerates are added to the mixed pulp raw material of the coated paper for printing. In the paper making process, it is preferably added after the mixer in which various pulps are mixed and before the head box. It is optimal to add it to the headbox.

  The pre-agglomerated filler ratio of the coated paper for printing of the present invention is 3 to 40 solids by weight. Preferably it is 5-30 solid weight%, More preferably, it is 7-25 solid weight%. If the solid content is less than 3% by weight, the yield of the filler is good and there is no problem of blisters or paper dust in an offset printing machine, but there is a problem that the printing surface is not excellent because of low smoothness. If the solid content exceeds 40% by weight, the pulp fiber content is low, so the yield of the filler is lowered, and the amount of paper powder is also a problem.

  In the present invention, as internal chemicals other than pulp and filler, dry paper strength agents such as polyacrylamide and cationized starch, and wet strength materials such as polyamidoamine epichlorohydrin can be added. In order to further increase the yield of the filler, a known inorganic flocculant (sulfuric acid band or the like) or an organic polymer flocculant can be added, and a known high-yield system (for example, a hydrocoal system, a compositor system). Etc.) can be used in combination.

  In the coated paper for printing of the present invention, in addition to the aforementioned internal chemicals, a bulking agent for paper can be internally added and contained in the paper. Specific examples of the bulking agent for paper include oil-based nonionic surfactants, sugar alcohol-based nonionic surfactants, sugar-based nonionic surfactants, polyhydric alcohol-type nonionic surfactants, polyvalent alcohols Ester compound of alcohol and fatty acid, polyoxyalkylene adduct of higher alcohol or higher fatty acid, polyoxyalkylene adduct of higher fatty acid ester, polyoxyalkylene adduct of polyhydric alcohol and fatty acid ester compound, fatty acid polyamidoamine, straight chain And fatty acid monoamide, unsaturated fatty acid monoamide, unsaturated fatty acid diamideamine and the like.

  This paper 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, an opacifier for paper described in JP-A-2000-273792, an additive for recycling used paper described in JP-A-2002-129497, an additive for recycling used paper described in JP-A-2002-275786, and JP-A-2002 -294586 additive for recycling used paper, bulking agent described in JP-A-2002-294594, paper described in JP-A-2003-96692 Bulking agent for use, bulking agent described in JP-A-2003-96693, additive for recycling used paper described in JP-A-2003-96694, additive for recycling used paper described in JP-A-2003-96695, JP-A-2003-171897 Paper thickness improver described in JP-A-2003-247197, paper bulking agent described in JP-A-2003-253588, paper bulking agent described in JP-A-2003-253589 , A paper bulking agent disclosed in JP-A-2003-253590, a paper density-reducing agent described in JP-A-2003-328297, a paper density-reducing agent described in JP-A-2003-313799, and Paper making additive described in Japanese Patent No. 11058, paper density reducing agent described in Japanese Patent Application Laid-Open No. 2004-27401, paper density reducing agent described in Japanese Patent Application Laid-Open No. 2004-115935, Japanese Patent Application Laid-Open No. 2004-76244 Paper bulking agent, paper modifying agent described in JP-A-2004-176213, paper softening agent described in Japanese Patent No. 3521422, bulky softening agent described in JP-A-2002-275792, JP 2003-286692 publication paper bulking agent, special Papermaking bulking agent composition described in JP 2004-270074, bulking agents papermaking 2004-285490 JP Patent.

The paper machine used for making the coated paper for printing of the present invention is preferably an on-top former, a gap former or the like having a double-side dewatering mechanism in order to suppress the two-sided nature of the paper. However, the present invention is not limited to this. The press, calendar, etc. may be processed under conditions within the normal operating range.
Moreover, in this invention, before providing a coating layer on a base paper, in order to suppress permeation to the base paper of a coating layer, you may apply a surface treating agent.

  Drugs applied in the present invention are raw starch, oxidized starch, esterified starch, cationized starch, heat-modified starch, enzyme-modified starch, aldehyde-modified starch, modified starch such as hydroxyethylated starch, carboxymethylcellulose, hydroxyethylcellulose, Cellulose derivatives such as 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, polyacrylates, Use polyacrylamide alone or in combination. Of these, the application of hydroxyethylated starch, which is excellent in surface strength improvement effect, is most preferable.

In addition to the above chemicals, the surface coating agent can be applied in combination with common surface sizing agents such as styrene acrylic acid, styrene maleic acid, and olefinic compounds. It has been found that a very good surface strength can be obtained by being cationic. The reason is that since the pre-aggregated filler in the present invention is cationic, the cationic surface sizing agent is applied with the sizing agent remaining on the surface, and the paper size is improved. If the size property is improved, the penetration of the coating layer into the base paper is further suppressed.
When a surface coating agent comprising a surface paper strength agent and a surface sizing agent is applied to the base paper, the mixing ratio of the surface paper strength agent and the surface sizing agent may be within a known range, and is not particularly limited.
The apparatus for applying the surface coating agent to the coating base paper is not particularly limited as long as it is a publicly available device such as a blade coater, a gate roll coater, or a size press coater.

  In the present invention, a coating layer mainly composed of a pigment and an adhesive is provided on the base paper obtained by the above method. As the pigment used in the coating layer, those conventionally used as coating pigments for paper can be used. The types of these pigments include inorganic pigments such as clay, kaolin, heavy calcium carbonate, light calcium carbonate, talc, titanium dioxide, barium sulfate, calcium sulfate, zinc oxide, silicic acid, silicate, colloidal silica, and satin white. Or organic pigments, such as a plastic pigment, are mentioned. These pigments can be used alone or in combination of two or more as required.

The adhesive used in the present invention is conventionally used for coated paper, such as styrene / butadiene, styrene / acrylic, ethylene / vinyl acetate, butadiene / methyl methacrylate, vinyl acetate / butyl acrylate, and the like. Synthetic adhesives such as various copolymers, or polyvinyl alcohol, maleic anhydride copolymer, acrylic acid / methyl methacrylate copolymer, casein, soy protein, synthetic protein and other proteins, oxidized starch, cationized starch, One or more kinds of starches such as urea phosphate esterified starch or hydroxyethyl etherified starch, cellulose derivatives such as carboxymethyl cellulose, hydroxymethyl cellulose or hydroxyethyl cellulose can be appropriately selected and used.
These adhesives are preferably used in the range of 5 to 35 parts by weight with respect to 100 parts by weight of the pigment. When the amount exceeds 35 parts by weight, the viscosity of the coating becomes high, and disadvantages such as the problem of operability such as difficulty in passing through the piping and the screen occur, which is not preferable. Moreover, when it is less than 5 parts by weight, a sufficient surface strength cannot be obtained, which is not preferable.
In the coating liquid of the present invention, various commonly used auxiliaries such as dispersants, thickeners, water retention agents, antifoaming agents, water resistance agents, dyes and fluorescent dyes can be used as auxiliaries.

In the present invention, the method for applying the adjusted coating solution to the base paper is not particularly limited, and a known coating apparatus can be used. Examples thereof include a blade coater, a bar coater, a roll coater, an air knife coater, a reverse roll coater, a curtain coater size press coater, and a gate roll coater. Using these, one or more layers are coated on one or both sides of the base paper. The coating amount per side is preferably 3 g / m 2 to 25 g / m 2, more preferably 5 g / m 2 to 15 g / m 2. When the coating amount per side is less than 3 g / m 2, sufficient base paper coverage cannot be obtained, resulting in poor ink depositability.
As a method for drying the wet coating layer, for example, a normal method such as a steam heater, a gas heater, an infrared heater, an electric heater, a hot air heater, a microwave or a cylinder dryer is used.

After drying, the coated paper for printing in the present invention can be given smoothness by a finishing process such as super calendering or high temperature soft calendering, which is post-processing, as necessary.
The density of the obtained coated paper for printing may be in the range of 0.4 to 1.3 g / cm ³ , and may be a level having a friction coefficient of ordinary coated printing paper.

EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, naturally this invention is not limited to these.
In the examples and comparative examples, “%” represents “% by weight” unless otherwise specified.

(1) Pre-aggregation filler adjustment method The pre-aggregation filler was obtained by mixing the treating agent and the filler using a static mixer.
The average particle size of the filler and the pre-agglomerated filler was measured with a master sizer 2000 manufactured by Malvern Instruments. The measurement principle is laser diffraction.
Hereinafter, synthesis examples of amphoteric or cationic acrylamide copolymers (PAM-1, PAM-2) and anionic acrylamide copolymers (PAM-3) as raw materials for the composite PAM of the present invention will be described.

[PAM-1]
670 parts of water, 262 parts of 50% aqueous acrylamide solution, 18.6 parts of 60% methacryloyloxyethyldimethylbenzylammonium chloride, 9.2 parts of dimethylaminopropylacrylamide, 3.9 parts of itaconic acid, 0.1 part of methylenebisacrylamide, A mixture of 0.5 parts of sodium allyl sulfonate was adjusted to pH 3 with 10% sulfuric acid.
Next, the temperature was raised to 60 ° C., 16 parts of 2% aqueous ammonium persulfate solution and 4 parts of 2% aqueous sodium sulfite solution were added, and the mixture was reacted at a temperature of 60 to 85 ° C. for 3 hours to obtain PAM-1.

[PAM-2]
670 parts of water, 262 parts of 50% acrylamide aqueous solution, 40.5 parts of 60% methacryloyloxyethyldimethylbenzylammonium chloride, 18.9 parts of dimethylaminoethyl methacrylate, 6.2 parts of 98% acrylic acid, sodium methallylsulfonate 0 .5 parts of the mixture was adjusted to pH 3 with 10% sulfuric acid.
Next, the temperature was raised to 60 ° C., 16 parts of 2% aqueous ammonium persulfate solution and 4 parts of 2% aqueous sodium sulfite solution were added, and the mixture was reacted at a temperature of 60 to 85 ° C. for 3 hours to obtain PAM-2.

[PAM-3]
A mixture of 670 parts of water, 262 parts of 50% aqueous acrylamide solution, 33.2 parts of 98% acrylic acid and 0.5 parts of sodium allyl sulfonate was adjusted to pH 3 with 10% sulfuric acid.
Next, the temperature was raised to 60 ° C., 16 parts of 2% aqueous ammonium persulfate solution and 4 parts of 2% aqueous sodium sulfite solution were added, and the mixture was reacted at a temperature of 60 to 85 ° C. for 3 hours to obtain PAM-3.
Next, an example in which PAM-1 obtained in Synthesis Examples 1 and 2 and an anionic polysaccharide (CMC) are mixed and adjusted to produce complex PAM-C1 will be described.
In addition, an example in which PAM-2 (amphoteric PAM) and PAM-3 (anionic PAM) obtained in Synthesis Example 3 above are mixed and adjusted to produce complex PAM-C2 without using an anionic polysaccharide. To state.

[Composite PAM1 (PAM-C1)]
CMC (anionic polysaccharide: component A) and PAM-1 (component B) were each mixed as a 1% solution at a weight ratio of A / B = 15/85 to obtain PAM-C1 (complexed PAM).
[Composite PAM2 (PAM-C2)]
Without using an anionic polysaccharide (CMC), the amphoteric PAM (PAM-2: B component) and anionic PAM (PAM-3: B component) weight ratio of PAM-2 / PAM-3 = 85/15 To obtain PAM-C2.

Next, the preparation method of the pre-aggregation filler which mixed composite PAM and the filler is shown.
[Pre-flocculated filler 1]
Heavy calcium carbonate (average particle size 1.5μm) as filler and composite PAM-C1 as pretreatment, pre-aggregation at a mixing ratio of heavy calcium carbonate / PAM-C1 = 100 / 0.7, and reserve with average particle size 27μm An agglomerated filler was obtained.

[Pre-flocculated filler 2]
Filler is light calcium carbonate (Rosetta type, average particle size 3μm), treatment agent is combined PAM-C1, pre-aggregated at a mixing ratio of heavy calcium carbonate / PAM-C1 = 100 / 0.7, average particle size 38μm A pre-agglomerated filler was obtained.

[Pre-flocculated filler 3]
Filler is light calcium carbonate (Rosetta type, average particle size 3μm), treatment agent is composite PAM-C1, pre-aggregation with light calcium carbonate / PAM-C1 = 100 / 0.2 mixing ratio, and reserve with average particle size 14μm An agglomerated filler was obtained.

[Pre-flocculated filler 4]
Filler is light calcium carbonate (Rosetta type, average particle size 3μm), treatment agent is combined PAM-C1, and pre-aggregation with light calcium carbonate / PAM-C1 = 100 / 2.5 mixing ratio. An agglomerated filler was obtained.

[Pre-flocculated filler 5]
Filler is light calcium carbonate (Rosetta type, average particle size 3μm), treatment agent is composite PAM-C1, pre-aggregation with light calcium carbonate / PAM-C1 = 100 / 0.05 mixing ratio, and reserve with average particle size 8μm An agglomerated filler was obtained.

[Pre-flocculated filler 6]
Filler is light calcium carbonate (Rosetta type, average particle size 3μm), treatment agent is composite PAM-C2, pre-aggregation with light calcium carbonate / PAM-C2 = 100 / 0.7 mixing ratio, and reserve with average particle size 8μm An agglomerated filler was obtained.

[Pre-flocculated filler 7]
The filler was light calcium carbonate (Rosetta type, average particle size 3 μm), the treating agent was CMC, and pre-aggregated at a light calcium carbonate / CMC = 100 / 0.7 mixing ratio to obtain a pre-agglomerated filler having an average particle size of 5 μm.

  Pre-flocculated filler is added to the raw pulp slurry (LKP / NKP / DIP = 75/15/10, cation requirement 14μeq / l), and the basis weight is 50.0g at a paper making speed of 1,000m / min. / m2 coated paper, coated with 6g / m2 of coating liquid 1 on both sides with an on-machine gate roll coater, dried, and then coated with coating liquid 2 on both sides of 16g / m2 with an off-machine blade coater. Coated and dried to obtain a coated paper for printing. Examples 1-5, Comparative Examples 1-6. About this coated paper for printing, the frequency | count of delamination and the amount of paper dust were measured by the printing test by the offset printing machine.

(1) Evaluation method for delamination, paper dust amount, and printing surface feeling Using an offset rotary press (Toshiba B2T-600), 880mm wide winding is performed at double speed color printing at 600rpm. 20,000 copies were printed and the number of blisters per 100 copies was measured. In addition, the amount of paper dust collected per 10 cm × 10 cm square of the blanket deposited paper powder after printing was measured. Furthermore, the printing surface feeling was evaluated visually (excellent: ◎, good: ◯, slightly inferior: Δ, x: inferior). The evaluation results are shown in Table 1.

(Coating fluid 1)
After adding 25 parts of hydroxyethyl etherified starch (PG295 manufactured by Penford) to a pigment slurry consisting of 100 parts of fine heavy calcium carbonate (Fimatech FMT-90), water was added to add 50% solids. A coating liquid 1 was obtained.

(Coating fluid 2)
To 100 parts of a pigment composed of 40 parts of fine kaolin (Japangloss, manufactured by JMHuber) and 60 parts of fine heavy calcium carbonate (FMT-90, manufactured by Phimatech), sodium polyacrylate was added as a dispersant (for inorganic pigments 0 .2 parts) Dispersed with a serie mixer to prepare a pigment slurry having a solid content of 70%. 10 parts of styrene / butadiene copolymer latex (glass transition temperature 20 ° C., gel content 85%) and 6 parts of hydroxyethyl etherified starch (PG295 manufactured by Penford) are added to the pigment slurry thus obtained. After that, water was further added to obtain a coating liquid 1 having a solid concentration of 60%.

[Example 1]
Paper stock obtained by adding the above-mentioned pre-flocculated filler 2 to the raw pulp slurry with a head box was made to obtain a coated base paper having an ash content of 15%. The coating liquid 1 is coated on the base paper with a gate roll coater so that the double-sided coating amount is 6 g / m2, and then dried, and then the coating liquid 2 is bladed so that the double-sided coating amount is 16 g / m2. Coated and dried with a coater to obtain a coated paper for printing.

[Example 2]
Paper stock obtained by adding the above-mentioned pre-flocculated filler 2 to the raw pulp slurry with a head box was made to obtain a coated base paper having an ash content of 30%. The coating liquid 1 is coated on the base paper with a gate roll coater so that the double-sided coating amount is 6 g / m2, and then dried, and then the coating liquid 2 is bladed so that the double-sided coating amount is 16 g / m2. Coated and dried with a coater to obtain a coated paper for printing.

[Example 3]
Paper stock obtained by adding the above-mentioned pre-flocculated filler 1 to the raw pulp slurry with a head box was made to obtain a coated base paper having a filler content in the paper of 15%. The coating liquid 1 is coated on the base paper with a gate roll coater so that the double-sided coating amount is 6 g / m2, and then dried, and then the coating liquid 2 is bladed so that the double-sided coating amount is 16 g / m2. Coated and dried with a coater to obtain a coated paper for printing.

[Example 4]
Paper stock obtained by adding the above-mentioned pre-flocculated filler 4 to the raw pulp slurry with a head box was made to obtain a coated base paper having an ash content of 15%. The coating liquid 1 is coated on the base paper with a gate roll coater so that the double-sided coating amount is 6 g / m2, and then dried, and then the coating liquid 2 is bladed so that the double-sided coating amount is 16 g / m2. Coated and dried with a coater to obtain a coated paper for printing.

[Example 5]
A paper stock obtained by adding the above-mentioned pre-aggregated filler 3 to the raw pulp slurry with a head box was made to obtain a coated base paper having an ash content of 15%. The coating liquid 1 is coated on the base paper with a gate roll coater so that the double-sided coating amount is 6 g / m2, and then dried, and then the coating liquid 2 is bladed so that the double-sided coating amount is 16 g / m2. Coated and dried with a coater to obtain a coated paper for printing.

[Comparative Example 1]
Paper stock obtained by separately adding the light calcium carbonate for the pre-flocculated filler 2 and the composite PAM in the head box to the slurry of the raw pulp was made to obtain a coated base paper having an ash content of 15%. The coating liquid 1 is coated on the base paper with a gate roll coater so that the double-sided coating amount is 6 g / m2, and then dried, and then the coating liquid 2 is bladed so that the double-sided coating amount is 16 g / m2. Coated and dried with a coater to obtain a coated paper for printing. The ratio of light calcium carbonate and composite PAM was the same as the ratio of pre-aggregated filler 2.

[Comparative Example 2]
Paper stock obtained by adding the above-mentioned pre-flocculated filler 2 to the raw pulp slurry with a head box was made to obtain a coated base paper having an ash content of 2%. The coating liquid 1 is coated on the base paper with a gate roll coater so that the double-sided coating amount is 6 g / m2, and then dried, and then the coating liquid 2 is bladed so that the double-sided coating amount is 16 g / m2. Coated and dried with a coater to obtain a coated paper for printing.

[Comparative Example 3]
Paper stock obtained by adding the above-mentioned pre-flocculated filler 2 to the raw pulp slurry with a head box was made to obtain a coated base paper having an ash content of 50%. The coating liquid 1 is coated on the base paper with a gate roll coater so that the double-sided coating amount is 6 g / m2, and then dried, and then the coating liquid 2 is bladed so that the double-sided coating amount is 16 g / m2. Coated and dried with a coater to obtain a coated paper for printing.

[Comparative Example 4]
Paper stock obtained by adding the above-mentioned pre-flocculated filler 6 to the raw pulp slurry with a head box was made to obtain a coated base paper having an ash content of 15%. The coating liquid 1 is coated on the base paper with a gate roll coater so that the double-sided coating amount is 6 g / m2, and then dried, and then the coating liquid 2 is bladed so that the double-sided coating amount is 16 g / m2. Coated and dried with a coater to obtain a coated paper for printing.

[Comparative Example 5]
Paper stock obtained by adding the above-mentioned pre-aggregated filler 7 to the raw pulp slurry with a head box was made to obtain a coated base paper having an ash content of 15%. The coating liquid 1 is applied to the base paper for printing with a gate roll coater so that the double-sided coating amount is 6 g / m2, and dried, and then the coating liquid 2 is bladed so that the double-sided coating amount is 16 g / m2. Coated and dried with a coater to obtain a coated paper for printing.

  From the results of Examples and Comparative Examples, it can be seen that in Examples 1 to 5, the number of delaminations, paper dust, and printing surface feeling are all good. From the comparison between Example 1 and Comparative Example 1, it can be seen that the strength and blister resistance of the paper are improved when the agglomerated filler is added than when the filler and the aggregating agent are added separately. From comparison between Examples 1 and 2 and Comparative Examples 2 and 3, if the ash content in the coated paper for printing is less than 3%, the see-through is large and the smoothness is low, so the printed surface is not excellent, and the ash content in the paper When it exceeds 40%, the amount of paper dust is large, and it can be seen that neither is practical. From the results of Comparative Examples 4 and 5, it can be seen that by adjusting the composite PAM only with the component (A) or the component (B), the effect of improving the strength is small and both are inferior in printability.

Claims (4)

A printing paper comprising a base paper provided with a coating layer containing a pigment and an adhesive, a composite comprising (A) an anionic polysaccharide and (B) a cationic and / or amphoteric acrylamide copolymer. A base paper containing a pre-aggregated filler having an average particle size of 10 to 80 μm by laser diffraction method, obtained by treating a filler with a fluorinated acrylamide copolymer, as 3 to 40 solids by weight as ash in the paper. Ah is, the weight ratio of the components (a) and component (B), coated printing paper, which is a a / B = 2 / 98~45 / 55.   2. The addition amount of the composite acrylamide copolymer composed of the component (A) and the component (B) is 0.1 to 3.0 solids weight% with respect to the filler. Coated paper for printing. The coated paper for printing according to claim 1 or 2 , wherein the filler is calcium carbonate. The coated paper for printing according to any one of claims 1 to 3 , wherein the density of the coated paper is 0.4 to 1.3 g / cm ³ or less.